WorldWideScience

Sample records for sdss early-type galaxies

  1. Testing the Presence of Multiple Photometric Components in Nearby Early-type Galaxies Using SDSS

    Oh, Semyeong; Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Lackner, Claire N., E-mail: semyeong@astro.princeton.edu [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa (Japan)

    2017-02-10

    We investigate two-dimensional image decomposition of nearby, morphologically selected early-type galaxies (ETGs). We are motivated by recent observational evidence of significant size growth of quiescent galaxies and theoretical development advocating a two-phase formation scenario for ETGs. We find that a significant fraction of nearby ETGs show changes in isophotal shape that require multi-component models. The characteristic sizes of the inner and outer component are ∼3 and ∼15 kpc. The inner component lies on the mass–size relation of ETGs at z ∼ 0.25–0.75, while the outer component tends to be more elliptical and hints at a stochastic buildup process. We find real physical differences between single- and double-component ETGs, with double-component galaxies being younger and more metal-rich. The fraction of double-component ETGs increases with increasing σ and decreases in denser environments. We hypothesize that double-component systems were able to accrete gas and small galaxies until later times, boosting their central densities, building up their outer parts, and lowering their typical central ages. In contrast, the oldest galaxies, perhaps due to residing in richer environments, have no remaining hints of their last accretion episode.

  2. SDSS-IV MaNGA: a distinct mass distribution explored in slow-rotating early-type galaxies

    Rong, Yu; Li, Hongyu; Wang, Jie; Gao, Liang; Li, Ran; Ge, Junqiang; Jing, Yingjie; Pan, Jun; Fernández-Trincado, J. G.; Valenzuela, Octavio; Ortíz, Erik Aquino

    2018-06-01

    We study the radial acceleration relation (RAR) for early-type galaxies (ETGs) in the SDSS MaNGA MPL5 data set. The complete ETG sample show a slightly offset RAR from the relation reported by McGaugh et al. (2016) at the low-acceleration end; we find that the deviation is due to the fact that the slow rotators show a systematically higher acceleration relation than the McGaugh's RAR, while the fast rotators show a consistent acceleration relation to McGaugh's RAR. There is a 1σ significant difference between the acceleration relations of the fast and slow rotators, suggesting that the acceleration relation correlates with the galactic spins, and that the slow rotators may have a different mass distribution compared with fast rotators and late-type galaxies. We suspect that the acceleration relation deviation of slow rotators may be attributed to more galaxy merger events, which would disrupt the original spins and correlated distributions of baryons and dark matter orbits in galaxies.

  3. SDSS-IV MaNGA: Uncovering the Angular Momentum Content of Central and Satellite Early-type Galaxies

    Greene, J. E.; Leauthaud, A.; Emsellem, E.; Ge, J.; Aragón-Salamanca, A.; Greco, J.; Lin, Y.-T.; Mao, S.; Masters, K.; Merrifield, M.; More, S.; Okabe, N.; Schneider, D. P.; Thomas, D.; Wake, D. A.; Pan, K.; Bizyaev, D.; Oravetz, D.; Simmons, A.; Yan, R.; van den Bosch, F.

    2018-01-01

    We study 379 central and 159 satellite early-type galaxies with two-dimensional kinematics from the integral-field survey Mapping Nearby Galaxies at APO (MaNGA) to determine how their angular momentum content depends on stellar and halo mass. Using the Yang et al. group catalog, we identify central and satellite galaxies in groups with halo masses in the range {10}12.5 {h}-1 {M}ȯ {10}11 {h}-2 {M}ȯ tend to have very little rotation, while nearly all galaxies at lower mass show some net rotation. The ∼30% of high-mass galaxies that have significant rotation do not stand out in other galaxy properties, except for a higher incidence of ionized gas emission. Our data are consistent with recent simulation results suggesting that major merging and gas accretion have more impact on the rotational support of lower-mass galaxies. When carefully matching the stellar mass distributions, we find no residual differences in angular momentum content between satellite and central galaxies at the 20% level. Similarly, at fixed mass, galaxies have consistent rotation properties across a wide range of halo mass. However, we find that errors in classification of central and satellite galaxies with group finders systematically lower differences between satellite and central galaxies at a level that is comparable to current measurement uncertainties. To improve constraints, the impact of group-finding methods will have to be forward-modeled via mock catalogs.

  4. SDSS-IV MaNGA: Variation of the Stellar Initial Mass Function in Spiral and Early-type Galaxies

    Li, Hongyu; Ge, Junqiang; Mao, Shude; Cappellari, Michele; Long, R. J.; Li, Ran; Emsellem, Eric; Dutton, Aaron A.; Li, Cheng; Bundy, Kevin; Thomas, Daniel; Drory, Niv; Lopes, Alexandre Roman

    2017-04-01

    We perform Jeans anisotropic modeling (JAM) on elliptical and spiral galaxies from the MaNGA DR13 sample. By comparing the stellar mass-to-light ratios estimated from stellar population synthesis and from JAM, we find a systematic variation of the initial mass function (IMF) similar to that in the earlier {{ATLAS}}3{{D}} results. Early-type galaxies (elliptical and lenticular) with lower velocity dispersions within one effective radius are consistent with a Chabrier-like IMF, while galaxies with higher velocity dispersions are consistent with a more bottom-heavy IMF such as the Salpeter IMF. Spiral galaxies have similar systematic IMF variations, but with slightly different slopes and larger scatters, due to the uncertainties caused by the higher gas fractions and extinctions for these galaxies. Furthermore, we examine the effects of stellar mass-to-light ratio gradients on our JAM modeling, and we find that the trends become stronger after considering the gradients.

  5. SDSS-IV MaNGA: The Spatially Resolved Stellar Initial Mass Function in ˜400 Early-Type Galaxies

    Parikh, Taniya; Thomas, Daniel; Maraston, Claudia; Westfall, Kyle B.; Goddard, Daniel; Lian, Jianhui; Meneses-Goytia, Sofia; Jones, Amy; Vaughan, Sam; Andrews, Brett H.; Bershady, Matthew; Bizyaev, Dmitry; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Drory, Niv; Emsellem, Eric; Law, David R.; Newman, Jeffrey A.; Roman-Lopes, Alexandre; Wake, David; Yan, Renbin; Zheng, Zheng

    2018-03-01

    MaNGA provides the opportunity to make precise spatially resolved measurements of the IMF slope in galaxies owing to its unique combination of spatial resolution, wavelength coverage and sample size. We derive radial gradients in age, element abundances and IMF slope analysing optical and near-infrared absorption features from stacked spectra out to the half-light radius of 366 early-type galaxies with masses 9.9 - 10.8 log M/M⊙. We find flat gradients in age and [α/Fe] ratio, as well as negative gradients in metallicity, consistent with the literature. We further derive significant negative gradients in the [Na/Fe] ratio with galaxy centres being well enhanced in Na abundance by up to 0.5 dex. Finally, we find a gradient in IMF slope with a bottom-heavy IMF in the centre (typical mass excess factor of 1.5) and a Milky Way-type IMF at the half-light radius. This pattern is mass-dependent with the lowest mass galaxies in our sample featuring only a shallow gradient around a Milky Way IMF. Our results imply the local IMF-σ relation within galaxies to be even steeper than the global relation and hint towards the local metallicity being the dominating factor behind the IMF variations. We also employ different stellar population models in our analysis and show that a radial IMF gradient is found independently of the stellar population model used. A similar analysis of the Wing-Ford band provides inconsistent results and further evidence of the difficulty in measuring and modelling this particular feature.

  6. SDSS-IV MaNGA: Probing the Kinematic Morphology–Density Relation of Early-type Galaxies with MaNGA

    Greene, J. E.; Leauthaud, A.; Emsellem, E.; Goddard, D.; Ge, J.; Andrews, B. H.; Brinkman, J.; Brownstein, J. R.; Greco, J.; Law, D.; Lin, Y.-T.; Masters, K. L.; Merrifield, M.; More, S.; Okabe, N.; Schneider, D. P.; Thomas, D.; Wake, D. A.; Yan, R.; Drory, N.

    2017-12-01

    The “kinematic” morphology–density relation for early-type galaxies posits that those galaxies with low angular momentum are preferentially found in the highest-density regions of the universe. We use a large sample of galaxy groups with halo masses {10}12.5MaNGA) survey to examine whether there is a correlation between local environment and rotational support that is independent of stellar mass. We find no compelling evidence for a relationship between the angular momentum content of early-type galaxies and either local overdensity or radial position within the group at fixed stellar mass.

  7. SDSS-IV MaNGA: global stellar population and gradients for about 2000 early-type and spiral galaxies on the mass-size plane

    Li, Hongyu; Mao, Shude; Cappellari, Michele; Ge, Junqiang; Long, R. J.; Li, Ran; Mo, H. J.; Li, Cheng; Zheng, Zheng; Bundy, Kevin; Thomas, Daniel; Brownstein, Joel R.; Roman Lopes, Alexandre; Law, David R.; Drory, Niv

    2018-05-01

    We perform full spectrum fitting stellar population analysis and Jeans Anisotropic modelling of the stellar kinematics for about 2000 early-type galaxies (ETGs) and spiral galaxies from the MaNGA DR14 sample. Galaxies with different morphologies are found to be located on a remarkably tight mass plane which is close to the prediction of the virial theorem, extending previous results for ETGs. By examining an inclined projection (`the mass-size' plane), we find that spiral and early-type galaxies occupy different regions on the plane, and their stellar population properties (i.e. age, metallicity, and stellar mass-to-light ratio) vary systematically along roughly the direction of velocity dispersion, which is a proxy for the bulge fraction. Galaxies with higher velocity dispersions have typically older ages, larger stellar mass-to-light ratios and are more metal rich, which indicates that galaxies increase their bulge fractions as their stellar populations age and become enriched chemically. The age and stellar mass-to-light ratio gradients for low-mass galaxies in our sample tend to be positive (centre Spiral galaxies with large mass and size have the steepest gradients, while the most massive ETGs, especially above the critical mass Mcrit ≳ 2 × 1011 M⊙, where slow rotator ETGs start dominating, have much flatter gradients. This may be due to differences in their evolution histories, e.g. mergers.

  8. Photometric properties of galaxies in the SDSS

    Hogg, D. W.; Blanton, M.; SDSS Collaboration

    2001-12-01

    We analyze the number density distribution of galaxy properties in a sample of 8x 104 galaxies from the Sloan Digital Sky Survey, in the redshift range 0.02calculated for each galaxy. The photometry is of excellent quality; every galaxy has CCD imaging with signal-to-noise for the flux well above 100. The distribution of galaxies in the (six-dimensional) space spanned by four colors, central surface-brightness, and radial concentration is described and analyzed, with the following results: \\textsl{(1)} The galaxies occupy only a small part of the six-dimensional space. \\textsl{(2)} The distribution of galaxy number density in the space is a strong function of intrinsic galaxy luminosity. \\textsl{(3)} Elliptical (or early type) and spiral (or late type) galaxies are clearly separated in the space. The ratio of early-type to late-type galaxy contributions to the luminosity density of the Universe is computed, as a function of wavelength. At 1 {μm }, early-type galaxies dominate the luminosity density. \\textsl{(4)} Outliers in color tend to be lower surface-brightness galaxies. Funding for the SDSS has been provided by the Alfred P. Sloan Foundation, the SDSS member institutions, NASA, NSF, DOE, the Japanese Monbukagakusho, and the Max Planck Society. This research has been supported by the NYU Faculty of Arts and Sciences.

  9. Chandra Early Type Galaxy Atals

    Kim, Dong-Woo; Anderson, Craig; Burke, Douglas J.; Fabbiano, Giuseppina; Fruscione, Antonella; Lauer, Jennifer; McCollough, Michael; Morgan, Douglas; Mossman, Amy; O'Sullivan, Ewan; Paggi, Alessandro; Vrtilek, Saeqa Dil; Trinchieri, Ginevra

    2017-08-01

    The hot gas in early type galaxies (ETGs) plays a crucial role in understanding their formation and evolution. As the hot gas is often extended to the outskirts beyond the optical size, the large scale structural features identified by Chandra (including jets, cavities, cold fronts, filaments and tails) point to key evolutionary mechanisms, e.g., AGN feedback, merging history, accretion, stripping and star formation and its quenching. We have systematically analyzed the archival Chandra data of ~100 ETGs to study the hot ISM. We produce the uniformly derived data products with spatially resolved spectral information and will make them accessible via a public web site. With 2D spectral infomation, we further discuss gas morphology, scaling relations, X-ray based mass profiles and their implications related to various physical mechanisms (e.g., stellar and AGN feedback).

  10. STAR FORMATION SIGNATURES IN OPTICALLY QUIESCENT EARLY-TYPE GALAXIES

    Salim, Samir; Rich, R. Michael

    2010-01-01

    In recent years, an argument has been made that a high fraction of early-type galaxies (ETGs) in the local universe experience low levels (∼ sun yr -1 ) of star formation (SF) that causes strong excess in UV flux, yet leaves the optical colors red. Many of these studies were based on Galaxy Evolution Explorer imaging of Sloan Digital Sky Survey (SDSS) galaxies (z ∼ 0.1), and were thus limited by its 5'' FWHM. Poor UV resolution left other possibilities for UV excess open, such as the old populations or an active galactic nucleus (AGN). Here, we study high-resolution far-ultraviolet HST/ACS images of optically quiescent early-type galaxies with strong UV excess. The new images show that three-quarters of these moderately massive (∼5 x 10 10 M sun ) ETGs shows clear evidence of extended SF, usually in form of wide or concentric UV rings, and in some cases, striking spiral arms. SDSS spectra probably miss these features due to small fiber size. UV-excess ETGs have on average less dust and larger UV sizes (D > 40 kpc) than other green-valley galaxies, which argues for an external origin for the gas that is driving the SF. Thus, most of these galaxies appear 'rejuvenated' (e.g., through minor gas-rich mergers or intergalactic medium accretion). For a smaller subset of the sample, the declining SF (from the original internal gas) cannot be ruled out. SF is rare in very massive early-types (M * > 10 11 M sun ), a possible consequence of AGN feedback. In addition to extended UV emission, many galaxies show a compact central source, which may be a weak, optically inconspicuous AGN.

  11. THE SLACS SURVEY. VIII. THE RELATION BETWEEN ENVIRONMENT AND INTERNAL STRUCTURE OF EARLY-TYPE GALAXIES

    Treu, Tommaso; Gavazzi, Raphael; Gorecki, Alexia; Marshall, Philip J.; Koopmans, Leon V. E.; Bolton, Adam S.; Moustakas, Leonidas A.; Burles, Scott

    2009-01-01

    We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens-the projected

  12. The Sizes of Early-Type Galaxies

    Janz, Joachim; Lisker, Thorsten

    2008-01-01

    In this letter we present a study of the size luminosity relation of 475 early-type galaxies in the Virgo Cluster with Sloan Digital Sky Survey imaging data. The analysis of our homogeneous, model-independent data set reveals that giant and dwarf early-type galaxies do not form one common sequence in this relation. The dwarfs seem to show weak or no dependence on luminosity, and do not fall on the extension of the rather steep relation of the giants. Under the assumption that the light profile shape varies continuously with magnitude, a curved relation of size and magnitude would be expected. While the galaxies do roughly follow this trend overall, we find that the dwarf galaxies are significantly larger and the low-luminosity giants are significantly smaller than what is predicted. We come to the conclusion that in this scaling relation there is not one common sequence from dwarfs to giants, but a dichotomy that cannot be resolved by varying profile shapes. The comparison of our data to a semianalytic model supports the idea of a physical origin for this dichotomy.

  13. Early-type galaxy core phase densities

    Carlberg, R. G.; Hartwick, F. D. A.

    2014-01-01

    Early-type galaxies have projected central density brightness profile logarithmic slopes, γ', ranging from about 0 to 1. We show that γ' is strongly correlated, r = 0.83, with the coarse grain phase density of the galaxy core, Q 0 ≡ ρ/σ 3 . The luminosity-γ' correlation is much weaker, r = –0.51. Q 0 also serves to separate the distribution of steep core profiles, γ' > 0.5, from shallow profiles, γ' < 0.3, although there are many galaxies of intermediate slope, at intermediate Q 0 , in a volume-limited sample. The transition phase density separating the two profile types is approximately 0.003 M ☉ pc –3 km –3 s 3 , which is also where the relation between Q 0 and core mass shows a change in slope, the rotation rate of the central part of the galaxy increases, and the ratio of the black hole to core mass increases. These relations are considered relative to the globular cluster inspiral core buildup and binary black hole core scouring mechanisms for core creation and evolution. Mass-enhanced globular cluster inspiral models have quantitative predictions that are supported by data, but no single model yet completely explains the correlations.

  14. ON THE SIZE AND COMOVING MASS DENSITY EVOLUTION OF EARLY-TYPE GALAXIES

    Van der Wel, Arjen; Bell, Eric F.; Van den Bosch, Frank C.; Gallazzi, Anna; Rix, Hans-Walter

    2009-01-01

    We present a simple, empirically motivated model that simultaneously predicts the evolution of the mean size and the comoving mass density of massive (>10 11 M sun ) early-type galaxies from z = 2 to the present. First, we demonstrate that some size evolution of the population can be expected simply due to the continuous emergence of early-type galaxies. The Sloan Digital Sky Survey (SDSS) data reveal that in the present-day universe more compact early-type galaxies with a given dynamical mass have older stellar populations. This implies that with increasing look-back time, the more extended galaxies will be more and more absent from the population. In contrast, at a given stellar velocity dispersion, SDSS data show that there is no relation between size and age, which implies that the velocity dispersion can be used to estimate the epoch at which galaxies stopped forming stars, turning into early-type galaxies. Based on this, we define an empirically motivated, redshift-dependent velocity dispersion threshold above which galaxies do not form stars at a significant rate, which we associate with the transformation into early-type galaxies. Applying this 'formation' criterion to a large sample of nearby early-type galaxies, we predict the redshift evolution in the size distribution and the comoving mass density. The resulting evolution in the mean size is roughly half of the observed evolution. Then we include a prescription for the merger histories of galaxies between the 'formation' redshift and the present, based on cosmological simulations of the assembly of dark matter halos. Such mergers after the transformation into an early-type galaxy are presumably dissipationless ('dry'), where the increase in size is expected to be approximately proportional to the increase in mass. This model successfully reproduces the observed evolution since z ∼ 2 in the mean size and in the comoving mass density of early-type galaxies with mass M > 10 11 M sun . We conclude that

  15. Herschel Spectroscopy of Early-type Galaxies

    Lapham, Ryen Carl; Young, Lisa M. [Physics Department, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 (United States); Crocker, Alison, E-mail: ryen.lapham@student.nmt.edu, E-mail: lyoung@physics.nmt.edu, E-mail: crockera@reed.edu [Physics Department, Reed College, Portland, OR 97202 (United States)

    2017-05-01

    We present Herschel spectroscopy of atomic lines arising in photodissociation regions as well as ionization regions of nearby early-type galaxies (ETGs), focusing on the volume-limited Atlas3D sample. Our data include the [C ii], [O i], and [N ii] 122 and 205 μ m lines, along with ancillary data including CO and H i maps. We find that ETGs have [C ii]/FIR ratios slightly lower than spiral galaxies in the KINGFISH sample, and several ETGs have unusually large [N ii] 122/[C ii] ratios. The [N ii] 122/[C ii] ratio is correlated with UV colors and there is a strong anti-correlation of [C ii]/FIR with NUV-K seen in both spirals and ETGs, likely due to a softer radiation field with fewer photons available to ionize carbon and heat the gas. The correlation thus makes a [C ii] deficit in galaxies with redder stellar populations. The high [N ii] 122/[C ii] (and low [C ii]/FIR) line ratios could also be affected by the removal of much of the diffuse, low-density gas, which is consistent with the low H i/H{sub 2} ratios. [C ii] is now being used as a star-formation indicator, and we find that it is just as good for ETGs as in spirals. The [C ii]/CO ratios found are also similar to those found in spiral galaxies. Through the use of the [N ii] 205 μ m line, estimates of the percentage of [C ii] emission arising from ionized gas indicate that a significant portion could arise in ionized regions.

  16. The influence of galaxy environment on the stellar initial mass function of early-type galaxies

    Rosani, Giulio; Pasquali, Anna; La Barbera, Francesco; Ferreras, Ignacio; Vazdekis, Alexandre

    2018-06-01

    In this paper, we investigate whether the stellar initial mass function (IMF) of early-type galaxies depends on their host environment. To this purpose, we have selected a sample of early-type galaxies from the SPIDER catalogue, characterized their environment through the group catalogue of Wang et al., and used their optical Sloan Digital Sky Survey (SDSS) spectra to constrain the IMF slope, through the analysis of IMF-sensitive spectral indices. To reach a high enough signal-to-noise ratio, we have stacked spectra in velocity dispersion (σ0) bins, on top of separating the sample by galaxy hierarchy and host halo mass, as proxies for galaxy environment. In order to constrain the IMF, we have compared observed line strengths and predictions of MIUSCAT/EMILES synthetic stellar population models, with varying age, metallicity, and `bimodal' (low-mass tapered) IMF slope (Γ _b). Consistent with previous studies, we find that Γ _b increases with σ0, becoming bottom-heavy (i.e. an excess of low-mass stars with respect to the Milky Way like IMF) at high σ0. We find that this result is robust against the set of isochrones used in the stellar population models, as well as the way the effect of elemental abundance ratios is taken into account. We thus conclude that it is possible to use currently state-of-the-art stellar population models and intermediate resolution spectra to consistently probe IMF variations. For the first time, we show that there is no dependence of Γb on environment or galaxy hierarchy, as measured within the 3 arcsec SDSS fibre, thus leaving the IMF as an intrinsic galaxy property, possibly set already at high redshift.

  17. Early-Type Galaxy Star Formation Histories in Different Environments

    Fitzpatrick, Patrick; Graves, G.

    2014-01-01

    We use very high-S/N stacked spectra of ˜29,000 nearby quiescent early-type galaxies (ETGs) from the Sloan Digital Sky Survey (SDSS) to investigate variations in their star formation histories (SFHs) with environment at fixed position along and perpendicular to the Fundamental Plane (FP). We separate galaxies in the three-dimensional FP space defined by galaxy effective radius Re, central stellar velocity dispersion σ, and surface brightness residual from the FP, ΔIe. We use the SDSS group catalogue of Yang et al. to further separate galaxies into three categories by their “identities” within their respective dark matter halos: central “Brightest Group Galaxies” (BGGs); Satellites; and Isolateds (those which are “most massive” in a dark matter halo with no Satellites). Within each category, we construct high-S/N mean stacked spectra to determine mean singleburst ages, [Fe/H], and [Mg/Fe] based on the stellar population synthesis models of R. Schiavon. This allows us to study variations in the stellar population properties (SPPs) with local group environment at fixed structure (i.e., fixed position in FP-space). We find that the SFHs of quiescent ETGs are almost entirely determined by their structural parameters σ and ΔIe. Any variation with local group environment at fixed structure is only slight: Satellites have the oldest stellar populations, 0.02 dex older than BGGs and 0.04 dex older than Isolateds; BGGs have the highest Fe-enrichments, 0.01 dex higher than Isolateds and 0.02 dex higher than Satellites; there are no differences in Mg-enhancement between BGGs, Isolateds, and Satellites. Our observation that, to zeroth-order, the SFHs of quiescent ETGs are fully captured by their structures places important qualitative constraints on the degree to which late-time evolutionary processes (those which occur after a galaxy’s initial formation and main star-forming lifetime) can alter their SFHs/structures.

  18. TIDAL INTERACTION AS THE ORIGIN OF EARLY-TYPE DWARF GALAXIES IN GROUP ENVIRONMENTS

    Paudel, Sanjaya; Ree, Chang H.

    2014-01-01

    We present a sample of dwarf galaxies that suffer ongoing disruption by the tidal forces of nearby massive galaxies. By analyzing structural and stellar population properties using the archival imaging and spectroscopic data from the Sloan Digital Sky Survey (SDSS), we find that they are likely a ''smoking gun'' example of the formation through tidal stirring of early-type dwarf galaxies (dEs) in the galaxy group environment. The inner cores of these galaxies are fairly intact and the observed light profiles are well fit by the Sérsic functions while the tidally stretched stellar halos are prominent in the outer parts. They are all located within a sky-projected distance of 50 kpc from the centers of the host galaxies and no dwarf galaxies have relative line-of-sight velocities larger than 205 km s –1 to their hosts. We derive the Composite Stellar Population properties of these galaxies by fitting the SDSS optical spectra to a multiple-burst composite stellar population model. We find that these galaxies accumulate a significant fraction of stellar mass within the last 1 Gyr and contain a majority stellar population with an intermediate age of 2 to 4 Gyr. Based on this evidence, we argue that tidal stirring, particularly through the galaxy-galaxy interaction, might have an important role in the formation and evolution of dEs in the group environment where the influence of other gas stripping mechanism might be limited

  19. The Intrinsic Shape of Galaxies in SDSS/Galaxy Zoo

    Rodríguez, Silvio; Padilla, Nelson D.

    2013-01-01

    By modelling the axis ratio distribution of SDSS DR8 galaxies we find the intrinsic 3D shapes of spirals and ellipticals. We use morphological information from the Galaxy Zoo project and assume a non-parametric distribution intrinsic of shapes, while taking into account dust extinction. We measure the dust extinction of the full sample of spiral galaxies and find a smaller value than previous estimations, with an edge-on extinction of $E_0 = 0.284^{+0.015}_{-0.026}$ in the SDSS r band. We als...

  20. CORES AND THE KINEMATICS OF EARLY-TYPE GALAXIES

    Lauer, Tod R.

    2012-01-01

    I have combined the Emsellem et al. ATLAS 3D rotation measures of a large sample of early-type galaxies with Hubble Space Telescope based classifications of their central structure to characterize the rotation velocities of galaxies with cores. 'Core galaxies' rotate slowly, while 'power-law galaxies' (galaxies that lack cores) rotate rapidly, confirming the analysis of Faber et al. Significantly, the amplitude of rotation sharply discriminates between the two types in the –19 > M V > –22 domain over which the two types coexist. The slow rotation in the small set of core galaxies with M V > –20, in particular, brings them into concordance with the more massive core galaxies. The ATLAS 3D 'fast-rotating' and 'slow-rotating' early-type galaxies are essentially the same as power-law and core galaxies, respectively, or the Kormendy and Bender two families of elliptical galaxies based on rotation, isophote shape, and central structure. The ATLAS 3D fast rotators do include roughly half of the core galaxies, but their rotation amplitudes are always at the lower boundary of that subset. Essentially, all core galaxies have ATLAS 3D rotation amplitudes λ R e /2 ≤0.25, while all galaxies with λ R e /2 >0.25 and figure eccentricity >0.2 lack cores. Both figure rotation and the central structure of early-type galaxies should be used together to separate systems that appear to have formed from 'wet' versus 'dry' mergers.

  1. The sloan lens acs survey. II. Stellar populations and internal structure of early-type lens galaxies

    Treu, Tommaso; Koopmans, Léon V.; Bolton, Adam S.; Burles, Scott; Moustakas, Leonidas A.

    2006-01-01

    We use HST images to derive effective radii and effective surface brightnesses of 15 early-type (E+S0) lens galaxies identified by the SLACS Survey. Our measurements are combined with stellar velocity dispersions from the SDSS database to investigate for the first time the distribution of lens

  2. Demise of faint satellites around isolated early-type galaxies

    Park, Changbom; Hwang, Ho Seong; Park, Hyunbae; Lee, Jong Chul

    2018-02-01

    The hierarchical galaxy formation scenario in the Cold Dark Matter cosmology with a non-vanishing cosmological constant Λ and geometrically flat space (ΛCDM) has been very successful in explaining the large-scale distribution of galaxies. However, there have been claims that ΛCDM over-predicts the number of satellite galaxies associated with massive galaxies compared with observations—the missing satellite galaxy problem1-3. Isolated groups of galaxies hosted by passively evolving massive early-type galaxies are ideal laboratories for identifying the missing physics in the current theory4-11. Here, we report—based on a deep spectroscopic survey—that isolated massive and passive early-type galaxies without any signs of recent wet mergers or accretion episodes have almost no satellite galaxies fainter than the r-band absolute magnitude of about Mr = -14. If only early-type satellites are used, the cutoff is at the somewhat brighter magnitude of about Mr = -15. Such a cutoff has not been found in other nearby satellite galaxy systems hosted by late-type galaxies or those with merger features. Various physical properties of satellites depend strongly on the host-centric distance. Our observations indicate that the satellite galaxy luminosity function is largely determined by the interaction of satellites with the environment provided by their host.

  3. The evolution of early-type galaxies in distant clusters

    Stanford, S.A.; Eisenhardt, P.R.; Dickinson, M.

    1998-01-01

    We present results from an optical-infrared photometric study of early-type (E+S0) galaxies in 19 galaxy clusters out to z=0.9. The galaxy sample is selected on the basis of morphologies determined from Hubble Space Telescope (HST) WFPC2 images and is photometrically defined in the K band in order to minimize redshift-dependent selection biases. Using new ground-based photometry in five optical and infrared bands for each cluster, we examine the evolution of the color-magnitude relation for early-type cluster galaxies, considering its slope, intercept, and color scatter around the mean relation. New multiwavelength photometry of galaxies in the Coma Cluster is used to provide a baseline sample at z∼0 with which to compare the distant clusters. The optical - IR colors of the early-type cluster galaxies become bluer with increasing redshift in a manner consistent with the passive evolution of an old stellar population formed at an early cosmic epoch. The degree of color evolution is similar for clusters at similar redshift and does not depend strongly on the optical richness or X-ray luminosity of the cluster, which suggests that the history of early-type galaxies is relatively insensitive to environment, at least above a certain density threshold. The slope of the color-magnitude relationship shows no significant change out to z=0.9, which provides evidence that it arises from a correlation between galaxy mass and metallicity, not age. Finally, the intrinsic scatter in the optical - IR colors of the galaxies is small and nearly constant with redshift, which indicates that the majority of giant, early-type galaxies in clusters share a common star formation history, with little perturbation due to uncorrelated episodes of later star formation. Taken together, our results are consistent with models in which most early-type galaxies in rich clusters are old, formed the majority of their stars at high redshift in a well-synchronized fashion, and evolved quiescently

  4. HOT GAS HALOS IN EARLY-TYPE FIELD GALAXIES

    Mulchaey, John S.; Jeltema, Tesla E.

    2010-01-01

    We use Chandra and XMM-Newton to study the hot gas content in a sample of field early-type galaxies. We find that the L X -L K relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. The low hot gas content of field galaxies with L K ∼ * suggests that internal processes such as supernovae-driven winds or active galactic nucleus feedback expel hot gas from low-mass galaxies. Such mechanisms may be less effective in groups and clusters where the presence of an intragroup or intracluster medium can confine outflowing material. In addition, galaxies in groups and clusters may be able to accrete gas from the ambient medium. While there is a population of L K ∼ * galaxies in groups and clusters that retain hot gas halos, some galaxies in these rich environments, including brighter galaxies, are largely devoid of hot gas. In these cases, the hot gas halos have likely been removed via ram pressure stripping. This suggests a very complex interplay between the intragroup/intracluster medium and hot gas halos of galaxies in rich environments, with the ambient medium helping to confine or even enhance the halos in some cases and acting to remove gas in others. In contrast, the hot gas content of more isolated galaxies is largely a function of the mass of the galaxy, with more massive galaxies able to maintain their halos, while in lower mass systems the hot gas escapes in outflowing winds.

  5. The intrinsic shape of galaxies in SDSS/Galaxy Zoo

    Rodríguez, Silvio; Padilla, Nelson D.

    2013-09-01

    By modelling the axis ratio distribution of Sloan Digital Sky Survey (SDSS) Data Release 8 galaxies, we find the intrinsic 3D shapes of spirals and ellipticals. We use morphological information from the Galaxy Zoo project and assume a non-parametric distribution intrinsic of shapes, while taking into account dust extinction. We measure the dust extinction of the full sample of spiral galaxies and find a smaller value than previous estimations, with an edge-on extinction of E_0 = 0.284^{+0.015}_{-0.026} in the SDSS r band. We also find that the distribution of minor to major axis ratio has a mean value of 0.267 ± 0.009, slightly larger than previous estimates mainly due to the lower extinction used; the same affects the circularity of galactic discs, which are found to be less round in shape than in previous studies, with a mean ellipticity of 0.215 ± 0.013. For elliptical galaxies, we find that the minor to major axis ratio, with a mean value of 0.584 ± 0.006, is larger than previous estimations due to the removal of spiral interlopers present in samples with morphological information from photometric profiles. These interlopers are removed when selecting ellipticals using Galaxy Zoo data. We find that the intrinsic shapes of galaxies and their dust extinction vary with absolute magnitude, colour and physical size. We find that bright elliptical galaxies are more spherical than faint ones, a trend that is also present with galaxy size, and that there is no dependence of elliptical galaxy shape with colour. For spiral galaxies, we find that the reddest ones have higher dust extinction as expected, due to the fact that this reddening is mainly due to dust. We also find that the thickness of discs increases with luminosity and size, and that brighter, smaller and redder galaxies have less round discs.

  6. Extended, regular HI structures around early-type galaxies

    Oosterloo, T.; Morganti, R.; Sadler, E. M. Van der; Hulst, J. M. van der; Serra, P.

    Abstract: We discuss the morphology and kinematics of the HI of a sample of 30 southern gas-rich early-type galaxies selected from the HI Parkes All-Sky Survey (HIPASS). This is the largest collection of high-resolution HI data of a homogeneously selected sample. Given the sensitivity of HIPASS,

  7. Dark matter distributions in early-type galaxies from strong gravitational lensing

    Eichner, Thomas Martin

    2013-01-01

    Dark matter constitutes a large fraction of the mass of early-type galaxies. However, the exact amount and spatial distribution of the dark matter, especially in the galaxies' center is still unclear. Furthermore, galaxies in dense environments such as the centers of galaxy clusters shrink in size, since parts of their outer dark matter halo is stripped away. The aim of this thesis is to measure the dark matter content in the centers and outskirts of elliptical galaxies by analyzing the strong gravitational lensing effect they produce. Gravitational lensing is well-suited for investigating dark matter, since it is sensitive to all forms of matter, regardless of its dynamical or evolutionary state. We present gravitational lensing studies of the exceptional strong lensing systems SDSS J1538+5817 and SDSS J1430+4105, identified by the Sloan Lens ACS survey. The lenses are elliptical galaxies at z l =0.143 and z l =0.285, respectively. For SDSS J1538+5817 we show that both multiple imaged sources are located at the same redshift z s =0.531. Its multiple images span a range from 1 to 4 kpc in the plane of the lens. For SDSS J1430+4105, the source at redshift z s =0.575 is imaged into a broad Einstein ring, covering radii from 4 kpc to 10 kpc in the plane of the lens. In both cases, the lensed images can be accurately and consistently reproduced with different modeling approaches. We get projected total masses of 8.11 +0.27 -0.59 x 10 10 M s un within the Einstein radius of 2.5 kpc for SDSS J1538+5817 and 5.37±0.06 x 10 11 M s un within 6.5 kpc for SDSS J1430+4105. The luminous and dark matter were traced separately, resulting in dark matter fractions within the Einstein radius of 0.1 +0.2 -0.1 and 0.40 +0.14 -0.10 for SDSS J1538+5817 and SDSS J1430+4105, respectively. We assume a de Vaucouleurs profile to trace the light distribution of both galaxies. From the stellar mass associated with this light, we can explicitly derive a stellar mass-to-light ratio of (M de

  8. Peculiar early-type galaxies with central star formation

    Ge Chong; Gu Qiusheng

    2012-01-01

    Early-type galaxies (ETGs) are very important for understanding the formation and evolution of galaxies. Recent observations suggest that ETGs are not simply old stellar spheroids as we previously thought. Widespread recent star formation, cool gas and dust have been detected in a substantial fraction of ETGs. We make use of the radial profiles of g — r color and the concentration index from the Sloan Digital Sky Survey database to pick out 31 peculiar ETGs with central blue cores. By analyzing the photometric and spectroscopic data, we suggest that the blue cores are caused by star formation activities rather than the central weak active galactic nucleus. From the results of stellar population synthesis, we find that the stellar population of the blue cores is relatively young, spreading from several Myr to less than one Gyr. In 14 galaxies with H I observations, we find that the average gas fraction of these galaxies is about 0.55. The bluer galaxies show a higher gas fraction, and the total star formation rate (SFR) correlates very well with the H I gas mass. The star formation history of these ETGs is affected by the environment, e.g. in the denser environment the H I gas is less and the total SFR is lower. We also discuss the origin of the central star formation of these early-type galaxies.

  9. SDSS IV MaNGA - Properties of AGN Host Galaxies

    Sánchez, S. F.; Avila-Reese, V.; Hernandez-Toledo, H.; Cortes-Suárez, E.; Rodríguez-Puebla, A.; Ibarra-Medel, H.; Cano-Díaz, M.; Barrera-Ballesteros, J. K.; Negrete, C. A.; Calette, A. R.; de Lorenzo-Cáceres, A.; Ortega-Minakata, R. A.; Aquino, E.; Valenzuela, O.; Clemente, J. C.; Storchi-Bergmann, T.; Riffel, R.; Schimoia, J.; Riffel, R. A.; Rembold, S. B.; Brownstein, J. R.; Pan, K.; Yates, R.; Mallmann, N.; Bitsakis, T.

    2018-04-01

    We present the characterization of the main properties of a sample of 98 AGN host galaxies, both type-II and type-I, in comparison with those of ≍2700 non-active galaxies observed by the MaNGA survey. We found that AGN hosts are morphologically early-type or early-spirals. AGN hosts are, on average, more massive, more compact, more centrally peaked and more pressure-supported systems. They are located in the intermediate/transition region between starforming and non-star-forming galaxies (i.e., the so-called green valley). We consider that they are in the process of halting/quenching the star formation. The analysis of the radial distributions of different properties shows that the quenching happens from inside-out involving both a decrease of the effciency of the star formation and a deficit of molecular gas. The data-products of the current analysis are distributed as a Value Added Catalog within the SDSS-DR14.

  10. Galaxy Clustering in Early SDSS Redshift Data

    Zehavi, I.; Frieman, Joshua A.; Weinberg, David H.; Mo, Houjun J.; Anderson, Scott F.; Strauss, Michael A.; Annis, James; Bahcall, Neta A.; Bernardi, Mariangela; Briggs, John W.; Brinkmann, Jon; Burles, Scott; Carey, Larry; Castander, Francisco J.; Connolly, J.; Csabai, Istvan; Dalcanton, Julianne J.; Dodelson,Scott; Doi,Mamoru; Eisenstein, Daniel; Evans, Michael L.; Finkbeiner, Douglas P.; Friedman, Scott; Fukugita, Masataka; Gunn, James E.; Hennessy, Greg S.; Hindsley, Robert B.; Ivezic, Zeljko; Kent,Stephen; Knapp, Gillian R.; Kron, Richard; Kunszt, Peter; Lamb, Donald; French Leger, R.; Long, Daniel C.; Loveday, Jon.; Lupton, Robert H.; McKay, Timothy; Meiksin, Avery; Merrelli, Aronne; Munn, Jeffrey A.; Narayanan, Vijay; Newcomb, Matt; Nichol, Robert C.; Owen, Russell; Peoples, John; Pope, Adrian; Rockosi, Constance M.; Schlegel, David; Schneider, Donald P.; Scoccimarro, Roman; Sheth, Ravi K.; Siegmund, Walter; Smee, Stephen; Snir, Yehuda; Stebbins, Albert; Stoughton, Christopher; SubbaRao, Mark; Szalay, Alexander S.; Szapudi, Istvan; Tegmark, Max; Tucker, Douglas L.; Uomoto, Alan; Vanden Berk, Dan; Vogeley, Michael S.; Waddell,Patrick; Yanny, Brian; York, Donald G.; Zehavi, Idit; Blanton, Michael R.; Frieman, Joshua A.; Weinberg, David H.; Mo, Houjun J.; Strauss, Michael A.

    2002-01-01

    We present the first measurements of clustering in the Sloan Digital Sky Survey (SDSS) galaxy redshift survey. Our sample consists of 29,300 galaxies with redshifts 5,700 km/s < cz < 39,000 km/s, distributed in several long but narrow (2.5-5 degree) segments, covering 690 square degrees. For the full, flux-limited sample, the redshift-space correlation length is approximately 8 Mpc/h. The two-dimensional correlation function \\xi(r_p,\\pi) shows clear signatures of both the small-scale, ``fingers-of-God'' distortion caused by velocity dispersions in collapsed objects and the large-scale compression caused by coherent flows, though the latter cannot be measured with high precision in the present sample. The inferred real-space correlation function is well described by a power law, \\xi(r)=(r/6.1+/-0.2 Mpc/h)^{-1.75+/-0.03}, for 0.1 Mpc/h < r < 16 Mpc/h. The galaxy pairwise velocity dispersion is \\sigma_{12} ~ 600+/-100 km/s for projected separations 0.15 Mpc/h < r_p < 5 Mpc/h. When we divide the...

  11. Constraints on early-type galaxy structure from spectroscopically selected gravitational lenses

    Bolton, Adam Stallard

    2005-11-01

    This thesis describes all aspects of a unique spectroscopic survey for strong galaxy-galaxy gravitational lenses: motivation, candidate selection, ground- based spectroscopic follow-up, Hubble Space Telescope imaging, data analysis, and results on the radial density profile of the lens galaxies. The lens candidates are selected from within the spectroscopic database of the Sloan Digital Sky Survey (SDSS) based on the appearance of two significantly different redshifts along the same line of sight, and lenses are confirmed within the candidate sample by follow-up imaging and spectroscopy. The sample of [approximate]20 early-type lenses presented in this thesis represents the largest single strong-lens galaxy sample discovered and published to date. These lenses probe the mass of the lens galaxies on scales roughly equal to one-half effective radius. We find a dynamical normalization between isothermal lens-model velocity dispersions and aperture-corrected SDSS stellar velocity dispersions of f = s lens /s stars = 0.95 +/- 0.03. By combining lens-model Einstein radii and de Vaucouleurs effective radii with stellar velocity dispersions through the Jeans equation, we find that the logarithmic slope [Special characters omitted.] of the density profile in our lens galaxies (r 0 ( [Special characters omitted.] ) is on average slightly steeper than isothermal ([Special characters omitted.] = 2) with a modest intrinsic scatter. Parameterizing the intrinsic distribution in [Special characters omitted.] as Gaussian, we find a maximum-likelihood mean of [Special characters omitted. ] and standard deviation of s[Special characters omitted.] = [Special characters omitted.] (68% confidence, for isotropic velocity-dispersion models). Our results rule out a single universal logarithmic density slope at >99.995% confidence. The success of this spectroscopic lens survey suggests that similar projects should be considered as an explicit science goal of future redshift surveys. (Copies

  12. MOLECULAR DISK PROPERTIES IN EARLY-TYPE GALAXIES

    Xu, X.; Walker, C.; Narayanan, D.

    2010-01-01

    We study the simulated CO emission from elliptical galaxies formed in the mergers of gas-rich disk galaxies. The cold gas not consumed in the merger-driven starburst quickly resettles into a disk-like configuration. By analyzing a variety of arbitrary merger orbits that produce a range of fast- to slow-rotating remnants, we find that molecular disk formation is a fairly common consequence of gas-rich galaxy mergers. Hence, if a molecular disk is observed in an early-type merger remnant, it is likely the result of a 'wet merger' rather than a 'dry merger'. We compare the physical properties from our simulated disks (e.g., size and mass) and find reasonably good agreement with recent observations. Finally, we discuss the detectability of these disks as an aid to future observations.

  13. Environmental Effects on the Metallicities of Early-Type Galaxies

    Jones, Christine; Oliversen, Ronald (Technical Monitor)

    2004-01-01

    We completed and published two papers in the Astrophysical Journal based on research from grant. In the first paper we analyzed nine X-ray-bright Virgo early-type galaxies observed by both ASCA and ROSAT. Through spatially resolved spectroscopy, we determined the radial temperature profiles and abundances of Mg, Si, and Fe for six galaxies. The temperature profiles are consistent with isothermal temperatures outside of cooler regions at the galaxies' centers. We present new evidence for iron abundance gradients in NGC 4472 and NGC 4649 and confirm the previous results on NGC 4636. Mg and Si abundance gradients on average are flatter than those of iron and correspond to an underabundance of α-process elements at high Fe values, while at low iron the element ratios favor enrichment by Type II supernovae (SNe). We explain the observed trend using the metallicity dependence of SN Ia metal production and present constraints on the available theoretical modeling for low-metallicity inhibition of SNe Ia. In the second paper We analyzed nine X-ray-bright Virgo early-type galaxies observed by both ASCA and ROSAT. Through spatially resolved spectroscopy, we determined the radial temperature profiles and abundances of Mg, Si, and Fe for six galaxies. The temperature profiles are consistent with isothermal temperatures outside of cooler regions at the galaxies' centers. We present new evidence for iron abundance gradients in NGC 4472 and NGC 4649 and confirm the previous results on NGC 4636. Mg and Si abundance gradients on average are flatter than those of iron and correspond to an underabundance of α-process elements at high Fe values, while at low iron the element ratios favor enrichment by Type I1 supernovae (SNe). We explain the observed trend using the metallicity dependence of SN Ia metal production and present constraints on the available theoretical modeling for low-metallicity inhibition of SNe Ia.

  14. Evolution of the clustering of photometrically selected SDSS galaxies

    Ross, Ashley; Percival, Will; Brunner, R.

    2010-01-01

    We measure the angular auto-correlation functions, ω(θ), of Sloan Digital Sky Survey (SDSS) galaxies selected to have photometric redshifts 0.1 < z < 0.4 and absolute r-band magnitudes Mr < −21.2. We split these galaxies into five overlapping redshift shells of width 0.1 and measure ω(θ) in each subsample in order to investigate the evolution of SDSS galaxies. We find that the bias increases substantially with redshift – much more so than one would expect for a passively evolving sample. We u...

  15. Redshift evolution of the dynamical properties of massive galaxies from SDSS-III/BOSS

    Beifiori, Alessandra; Saglia, Roberto P.; Bender, Ralf; Senger, Robert [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany); Thomas, Daniel; Maraston, Claudia; Steele, Oliver; Masters, Karen L.; Pforr, Janine; Tojeiro, Rita; Johansson, Jonas; Nichol, Robert C. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom); Chen, Yan-Mei; Wake, David [Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706 (United States); Bolton, Adam; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Leauthaud, Alexie [Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Chiba 277-8582 (Japan); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Skibba, Ramin [Department of Physics, Center for Astrophysics and Space Sciences, University of California, 9500 Gilman Drive, San Diego, CA 92093 (United States); Pan, Kaike, E-mail: beifiori@mpe.mpg.de [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); and others

    2014-07-10

    We study the redshift evolution of the dynamical properties of ∼180, 000 massive galaxies from SDSS-III/BOSS combined with a local early-type galaxy sample from SDSS-II in the redshift range 0.1 ≤ z ≤ 0.6. The typical stellar mass of this sample is M{sub *} ∼2 × 10{sup 11} M{sub ☉}. We analyze the evolution of the galaxy parameters effective radius, stellar velocity dispersion, and the dynamical to stellar mass ratio with redshift. As the effective radii of BOSS galaxies at these redshifts are not well resolved in the Sloan Digital Sky Survey (SDSS) imaging we calibrate the SDSS size measurements with Hubble Space Telescope/COSMOS photometry for a sub-sample of galaxies. We further apply a correction for progenitor bias to build a sample which consists of a coeval, passively evolving population. Systematic errors due to size correction and the calculation of dynamical mass are assessed through Monte Carlo simulations. At fixed stellar or dynamical mass, we find moderate evolution in galaxy size and stellar velocity dispersion, in agreement with previous studies. We show that this results in a decrease of the dynamical to stellar mass ratio with redshift at >2σ significance. By combining our sample with high-redshift literature data, we find that this evolution of the dynamical to stellar mass ratio continues beyond z ∼ 0.7 up to z > 2 as M{sub dyn}/M{sub *} ∼(1 + z){sup –0.30±0.12}, further strengthening the evidence for an increase of M{sub dyn}/M{sub *} with cosmic time. This result is in line with recent predictions from galaxy formation simulations based on minor merger driven mass growth, in which the dark matter fraction within the half-light radius increases with cosmic time.

  16. Redshift evolution of the dynamical properties of massive galaxies from SDSS-III/BOSS

    Beifiori, Alessandra; Saglia, Roberto P.; Bender, Ralf; Senger, Robert; Thomas, Daniel; Maraston, Claudia; Steele, Oliver; Masters, Karen L.; Pforr, Janine; Tojeiro, Rita; Johansson, Jonas; Nichol, Robert C.; Chen, Yan-Mei; Wake, David; Bolton, Adam; Brownstein, Joel R.; Leauthaud, Alexie; Schneider, Donald P.; Skibba, Ramin; Pan, Kaike

    2014-01-01

    We study the redshift evolution of the dynamical properties of ∼180, 000 massive galaxies from SDSS-III/BOSS combined with a local early-type galaxy sample from SDSS-II in the redshift range 0.1 ≤ z ≤ 0.6. The typical stellar mass of this sample is M * ∼2 × 10 11 M ☉ . We analyze the evolution of the galaxy parameters effective radius, stellar velocity dispersion, and the dynamical to stellar mass ratio with redshift. As the effective radii of BOSS galaxies at these redshifts are not well resolved in the Sloan Digital Sky Survey (SDSS) imaging we calibrate the SDSS size measurements with Hubble Space Telescope/COSMOS photometry for a sub-sample of galaxies. We further apply a correction for progenitor bias to build a sample which consists of a coeval, passively evolving population. Systematic errors due to size correction and the calculation of dynamical mass are assessed through Monte Carlo simulations. At fixed stellar or dynamical mass, we find moderate evolution in galaxy size and stellar velocity dispersion, in agreement with previous studies. We show that this results in a decrease of the dynamical to stellar mass ratio with redshift at >2σ significance. By combining our sample with high-redshift literature data, we find that this evolution of the dynamical to stellar mass ratio continues beyond z ∼ 0.7 up to z > 2 as M dyn /M * ∼(1 + z) –0.30±0.12 , further strengthening the evidence for an increase of M dyn /M * with cosmic time. This result is in line with recent predictions from galaxy formation simulations based on minor merger driven mass growth, in which the dark matter fraction within the half-light radius increases with cosmic time.

  17. LUMINOUS SATELLITES OF EARLY-TYPE GALAXIES. I. SPATIAL DISTRIBUTION

    Nierenberg, A. M.; Auger, M. W.; Treu, T.; Marshall, P. J.; Fassnacht, C. D.

    2011-01-01

    We study the spatial distribution of faint satellites of intermediate redshift (0.1 s = 1.7 +0.9 -0.8 ) that is comparable to the number of Milky Way satellites with similar host-satellite contrast. The average projected radial profile of the satellite distribution is isothermal (γ p = -1.0 +0.3 -0.4 ), which is consistent with the observed central mass density profile of massive early-type galaxies. Furthermore, the satellite distribution is highly anisotropic (isotropy is ruled out at a >99.99% confidence level). Defining φ to be the offset between the major axis of the satellite spatial distribution and the major axis of the host light profile, we find a maximum posterior probability of φ = 0 and |φ| less than 42 0 at the 68% confidence level. The alignment of the satellite distribution with the light of the host is consistent with simulations, assuming that light traces mass for the host galaxy as observed for lens galaxies. The anisotropy of the satellite population enhances its ability to produce the flux ratio anomalies observed in gravitationally lensed quasars.

  18. The SDSS Coadd: A Galaxy Photometric Redshift Catalog

    Reis, Ribamar R.R.; /Fermilab /Rio de Janeiro Federal U.; Soares-Santos, Marcelle; /Fermilab /Inst. Geo. Astron., Havana /Sao Paulo U.; Annis, James; /Fermilab; Dodelson, Scott; /Fermilab /Chicago U. /Chicago U., KICP; Hao, Jiangang; /Fermilab; Johnston, David; /Fermilab; Kubo, Jeffrey; /Fermilab; Lin, Huan; /Fermilab; Seo, Hee-Jong; /UC, Berkeley; Simet, Melanie; /Chicago U.

    2011-11-01

    We present and describe a catalog of galaxy photometric redshifts (photo-z's) for the Sloan Digital Sky Survey (SDSS) Coadd Data. We use the Artificial Neural Network (ANN) technique to calculate photo-z's and the Nearest Neighbor Error (NNE) method to estimate photo-z errors for {approx} 13 million objects classified as galaxies in the coadd with r < 24.5. The photo-z and photo-z error estimators are trained and validated on a sample of {approx} 89, 000 galaxies that have SDSS photometry and spectroscopic redshifts measured by the SDSS Data Release 7 (DR7), the Canadian Network for Observational Cosmology Field Galaxy Survey (CNOC2), the Deep Extragalactic Evolutionary Probe Data Release 3(DEEP2 DR3), the SDSS-III's Baryon Oscillation Spectroscopic Survey (BOSS), the Visible imaging Multi-Object Spectrograph - Very Large Telescope Deep Survey (VVDS) and the WiggleZ Dark Energy Survey. For the best ANN methods we have tried, we find that 68% of the galaxies in the validation set have a photo-z error smaller than {sigma}{sub 68} = 0.036. After presenting our results and quality tests, we provide a short guide for users accessing the public data.

  19. X-Ray Scaling Relations of Early-type Galaxies

    Babyk, Iu. V.; McNamara, B. R.; Nulsen, P. E. J.; Hogan, M. T.; Vantyghem, A. N.; Russell, H. R.; Pulido, F. A.; Edge, A. C.

    2018-04-01

    X-ray luminosity, temperature, gas mass, total mass, and their scaling relations are derived for 94 early-type galaxies (ETGs) using archival Chandra X-ray Observatory observations. Consistent with earlier studies, the scaling relations, L X ∝ T 4.5±0.2, M ∝ T 2.4±0.2, and L X ∝ M 2.8±0.3, are significantly steeper than expected from self-similarity. This steepening indicates that their atmospheres are heated above the level expected from gravitational infall alone. Energetic feedback from nuclear black holes and supernova explosions are likely heating agents. The tight L X –T correlation for low-luminosity systems (i.e., below 1040 erg s‑1) are at variance with hydrodynamical simulations, which generally predict higher temperatures for low-luminosity galaxies. We also investigate the relationship between total mass and pressure, Y X = M g × T, finding M\\propto {Y}X0.45+/- 0.04. We explore the gas mass to total mass fraction in ETGs and find a range of 0.1%–1.0%. We find no correlation between the gas-to-total mass fraction with temperature or total mass. Higher stellar velocity dispersions and higher metallicities are found in hotter, brighter, and more massive atmospheres. X-ray core radii derived from β-model fitting are used to characterize the degree of core and cuspiness of hot atmospheres.

  20. SDSS-IV MaNGA: stellar population gradients as a function of galaxy environment

    Goddard, D.; Thomas, D.; Maraston, C.; Westfall, K.; Etherington, J.; Riffel, R.; Mallmann, N. D.; Zheng, Z.; Argudo-Fernández, M.; Bershady, M.; Bundy, K.; Drory, N.; Law, D.; Yan, R.; Wake, D.; Weijmans, A.; Bizyaev, D.; Brownstein, J.; Lane, R. R.; Maiolino, R.; Masters, K.; Merrifield, M.; Nitschelm, C.; Pan, K.; Roman-Lopes, A.; Storchi-Bergmann, T.

    2017-02-01

    We study the internal radial gradients of stellar population properties within 1.5 Re and analyse the impact of galaxy environment. We use a representative sample of 721 galaxies with masses ranging between 109 M⊙ and 1011.5 M⊙ from the SDSS-IV survey MaNGA. We split this sample by morphology into early-type and late-type galaxies. Using the full spectral fitting code FIREFLY, we derive the light and mass-weighted stellar population properties, age and metallicity, and calculate the gradients of these properties. We use three independent methods to quantify galaxy environment, namely the Nth nearest neighbour, the tidal strength parameter Q and distinguish between central and satellite galaxies. In our analysis, we find that early-type galaxies generally exhibit shallow light-weighted age gradients in agreement with the literature and mass-weighted median age gradients tend to be slightly positive. Late-type galaxies, instead, have negative light-weighted age gradients. We detect negative metallicity gradients in both early- and late-type galaxies that correlate with galaxy mass, with the gradients being steeper and the correlation with mass being stronger in late-types. We find, however, that stellar population gradients, for both morphological classifications, have no significant correlation with galaxy environment for all three characterizations of environment. Our results suggest that galaxy mass is the main driver of stellar population gradients in both early and late-type galaxies, and any environmental dependence, if present at all, must be very subtle.

  1. The outer disks of early-type galaxies. I. Surface-brightness profiles of barred galaxies

    Erwin, Peter; Pohlen, Michael; Beckman, John E.

    We present a study of 66 barred, early-type (S0-Sb) disk galaxies, focused on the disk surface brightness profile outside the bar region, with the aim of throwing light on the nature of Freeman type I and II profiles, their origins, and their possible relation to disk truncations. This paper

  2. Kinematic properties and dark matter fraction of Virgo dwarf early-type galaxies

    Toloba, E.; Boselli, A.; Peletier, R.; Gorgas, J.

    2012-01-01

    What happens to dwarf galaxies as they enter the cluster potential well is one of the main unknowns in studies of galaxy evolution. Several evidence suggests that late-type galaxies enter the cluster and are transformed to dwarf early-type galaxies (dEs). We study the Virgo cluster to understand

  3. Young stellar populations in early-type galaxies in the Sloan Digital Sky Survey

    Nolan, Louisa A.; Raychaudhury, Somak; Kabán, Ata

    2007-02-01

    We use a purely data-driven rectified factor analysis to identify early-type galaxies with recent star formation in Data Release 4 of the Sloan Digital Sky Survey Spectroscopic Catalogue. We compare the spectra and environment of these galaxies with those of `normal' early-type galaxies, and a sample of independently selected E+A galaxies. We calculate the projected local galaxy surface density from the nearest five and 10 neighbours (Σ5 and Σ10) for each galaxy in our sample, and find that the dependence on projected local density, of the properties of E+A galaxies, is not significantly different from that of early-type galaxies with young stellar populations, dropping off rapidly towards denser environments, and flattening off at densities ~10 per cent of the stellar mass in these galaxies. This, together with the similarity of the environments in which this `E+F' population and the E+A galaxy sample are found, suggests that E+F galaxies used to be E+A galaxies, but have evolved by a further ~ one to a few Gyr. Our rectified factor analysis is sensitive enough to identify this hidden population, which allows us to study the global and intrinsic properties of early-type galaxies created in major mergers or interactions, and compare them with those early-types which have had the bulk of their stars in place since a much earlier epoch.

  4. COLOR-MAGNITUDE RELATIONS OF EARLY-TYPE DWARF GALAXIES IN THE VIRGO CLUSTER: AN ULTRAVIOLET PERSPECTIVE

    Kim, Suk; Rey, Soo-Chang; Lisker, Thorsten; Sohn, Sangmo Tony

    2010-01-01

    We present ultraviolet (UV) color-magnitude relations (CMRs) of early-type dwarf galaxies in the Virgo cluster, based on Galaxy Evolution Explorer (GALEX) UV and Sloan Digital Sky Survey (SDSS) optical imaging data. We find that dwarf lenticular galaxies (dS0s), including peculiar dwarf elliptical galaxies (dEs) with disk substructures and blue centers, show a surprisingly distinct and tight locus separated from that of ordinary dEs, which is not clearly seen in previous CMRs. The dS0s in UV CMRs follow a steeper sequence than dEs and show bluer UV-optical color at a given magnitude. We also find that the UV CMRs of dEs in the outer cluster region are slightly steeper than that of their counterparts in the inner region, due to the existence of faint, blue dEs in the outer region. We explore the observed CMRs with population models of a luminosity-dependent delayed exponential star formation history. We confirm that the feature of delayed star formation of early-type dwarf galaxies in the Virgo cluster is strongly correlated with their morphology and environment. The observed CMR of dS0s is well matched by models with relatively long delayed star formation. Our results suggest that dS0s are most likely transitional objects at the stage of subsequent transformation of late-type progenitors to ordinary red dEs in the cluster environment. In any case, UV photometry provides a powerful tool to disentangle the diverse subpopulations of early-type dwarf galaxies and uncover their evolutionary histories.

  5. The hELENa project - I. Stellar populations of early-type galaxies linked with local environment and galaxy mass

    Sybilska, A.; Lisker, T.; Kuntschner, H.; Vazdekis, A.; van de Ven, G.; Peletier, R.; Falcón-Barroso, J.; Vijayaraghavan, R.; Janz, J.

    2017-01-01

    We present the first in a series of papers in The role of Environment in shaping Low-mass Early-type Nearby galaxies (hELENa) project. In this paper, we combine our sample of 20 low-mass early types (dEs) with 258 massive early types (ETGs) from the ATLAS3D survey - all observed with the SAURON

  6. On the fairness of the main galaxy sample of SDSS

    Meng Kelai; Pan Jun; Feng Longlong; Ma Bin

    2011-01-01

    Flux-limited and volume-limited galaxy samples are constructed from the Sloan Digital Sky Survey (SDSS) data releases DR4, DR6 and DR7 for statistical analysis. The two-point correlation functions ξ(s), monopole of three-point correlation functions ζ 0 , projected two-point correlation function w p and pairwise velocity dispersion σ 12 are measured to test if galaxy samples are fair for these statistics. We find that with the increment of sky coverage of subsequent data releases in SDSS, ξ(s) of the flux-limited sample is extremely robust and insensitive to local structures at low redshift. However, for volume-limited samples fainter than L* at large scales s > or approx. 10 h -1 Mpc, the deviation of ξ(s) from different SDSS data releases (DR7, DR6 and DR4) increases with the increment of absolute magnitude. The case of ζ 0 (s) is similar to that of ξ(s). In the weakly nonlinear regime, there is no agreement between ζ 0 of different data releases in all luminosity bins. Furthermore, w p of volume-limited samples of DR7 in luminosity bins fainter than -M r,0.1 = [18.5, 19.5] are significantly larger and σ 12 of the two faintest volume-limited samples of DR7 display a very different scale dependence than results from DR4 and DR6. Our findings call for caution in understanding clustering analysis results of SDSS faint galaxy samples and higher order statistics of SDSS volume-limited samples in the weakly nonlinear regime. The first zero-crossing points of ξ(s) from volume-limited samples are also investigated and discussed. (research papers)

  7. THE UBIQUITOUS RADIO CONTINUUM EMISSION FROM THE MOST MASSIVE EARLY-TYPE GALAXIES

    Brown, Michael J. I.; Jannuzi, Buell T.; Floyd, David J. E.; Mould, Jeremy R.

    2011-01-01

    We have measured the radio continuum emission of 396 early-type galaxies brighter than K = 9, using 1.4 GHz imagery from the NRAO Very Large Array Sky Survey, Green Bank 300 ft Telescope, and 64 m Parkes Radio Telescope. For M K K < -25.5 early-type galaxies are greater than zero in all cases. It is thus highly likely that the most massive galaxies always host an active galactic nucleus or have recently undergone star formation.

  8. THE ENVIRONMENTAL DEPENDENCE OF THE FRACTION OF 'UNCONVENTIONAL' GALAXIES: RED LATE TYPES AND BLUE EARLY TYPES

    Deng Xinfa; He Jizhou; Wu Ping; Ding Yingping

    2009-01-01

    From the Main galaxy sample of the Sloan Digital Sky Survey Data Release 6, we construct two volume-limited samples with the luminosity -20.0 ≤ M r ≤ -18.5 and -22.40 ≤ M r ≤ -20.16, respectively, to explore the environmental dependence of the fraction of 'unconventional' galaxies: red late types and blue early types. We use the density estimator within the distance to the fifth nearest neighbor, and construct two samples at both extremes of density and perform comparative studies between them for each volume-limited sample. Results of two volume-limited samples show the same conclusions: the fraction of red late-type galaxies rises considerably with increasing local density, and that one of the blue early-type galaxies declines substantially with increasing local density. In addition, we note that bluer galaxies preferentially are late types, but the red galaxies are not dominated by early types.

  9. Powerful warm infrared sources in early-type galaxies

    Dressel, L.L.

    1988-01-01

    IRAS far-infrared sources have been identified with 129 S0, Sa, Sb, and Sc galaxies in a statistically complete sample of 738 galaxies brighter than 14.5 mag and smaller than 4.0 arcmin. In most cases, the far-IR colors and the ratios of far-IR flux to radio flux density are those of normal galactic disks and/or starbursts. The most powerful far-IR sources in S0 and Sa galaxies are just as powerful as the strongest far-IR sources in Sb and Sc galaxies. Bright-IR sources in S0 and Sa galaxies are warm; those in Sc galaxies are cool. Sb galaxies have both warm and cool IR sources. Bright warm IR sources occur much more frequently in barred galaxies than in galaxies without bars for types S0, Sa, and Sb. Bright, cool IR sources are found with increasing frequency along the Hubble sequence, regardless of the presence or absence of a bar. At least some S0 galaxies with warm, bright IR sources have peculiar morphologies and ambiguous classifications. 22 references

  10. Photometric redshifts of galaxies from SDSS and 2MASS

    Wang Tao; Gu Qiusheng; Huang Jiasheng

    2009-01-01

    In order to find the physical parameters which determine the accuracy of photometric redshifts, we compare the spectroscopic and photometric redshifts (photo-z's) for a large sample of ∼ 80000 SDSS-2MASS galaxies. Photo-z's in this paper are estimated by using the artificial neural network photometric redshift method (ANNz). For a subset of ∼40000 randomly selected galaxies, we find that the photometric redshift recovers the spectroscopic redshift distribution very well with rms of 0.016. Our main results are as follows: (1) Using magnitudes directly as input parameters produces more accurate photo-z's than using colors; (2) The inclusion of 2MASS (J, H, K s ) bands does not improve photo-z's significantly, which indicates that near infrared data might not be important for the low-redshift sample; (3) Adding the concentration index (essentially the steepness of the galaxy brightness profile) as an extra input can improve the photo-z's estimation up to ∼ 10 percent; (4) Dividing the sample into early- and late-type galaxies by using the concentration index, normal and abnormal galaxies by using the emission line flux ratios, and red and blue galaxies by using color index (g - r), we can improve the accuracy of photo-z's significantly; (5) Our analysis shows that the outliers (where there is a big difference between the spectroscopic and photometric redshifts) are mainly correlated with galaxy types, e.g., most outliers are late-type (blue) galaxies.

  11. ULTRAVIOLET COLOR-COLOR RELATION OF EARLY-TYPE GALAXIES AT 0.05 < z < 0.12

    Ree, Chang H.; Jeong, Hyunjin; Lee, Joon Hyeop; Kim, Sang Chul; Kyeong, Jaemann; Oh, Kyuseok; Chung, Chul

    2012-01-01

    We present the ultraviolet (UV) color-color relation of early-type galaxies (ETGs) in the nearby universe (0.05 < z < 0.12) to investigate the properties of hot stellar populations responsible for the UV excess (UVX). The initial sample of ETGs is selected by the spectroscopic redshift and the morphology parameter from the Sloan Digital Sky Survey (SDSS) Data Release 7, and then cross-matched with the Galaxy Evolution Explorer (GALEX) far-UV (FUV) and near-UV (NUV) GR6 data. The cross-matched ETG sample is further classified by their emission line characteristics in the optical spectra into quiescent, star-forming, and active galactic nucleus categories. Contaminations from early-type spiral galaxies, mergers, and morphologically disturbed galaxies are removed by visual inspection. By drawing the FUV-NUV (as a measure of UV spectral shape) versus FUV – r (as a measure of UVX strength) diagram for the final sample of ∼3700 quiescent ETGs, we find that the 'old and dead' ETGs consist of a well-defined sequence in UV colors, the 'UV red sequence', so that the stronger UVX galaxies should have a harder UV spectral shape systematically. However, the observed UV spectral slope is too steep to be reproduced by the canonical stellar population models in which the UV flux is mainly controlled by age or metallicity parameters. Moreover, 2 mag of color spreads both in FUV-NUV and FUV – r appear to be ubiquitous among any subsets in distance or luminosity. This implies that the UVX in ETGs could be driven by yet another parameter which might be even more influential than age or metallicity.

  12. Formation and evolution of dwarf early-type galaxies in the Virgo cluster I. Internal kinematics

    Toloba, E.; Boselli, A.; Cenarro, A. J.; Peletier, R. F.; Gorgas, J.; Gil de Paz, A.; Munoz-Mateos, J. C.

    We present new medium resolution kinematic data for a sample of 21 dwarf early-type galaxies (dEs) mainly in the Virgo cluster, obtained with the WHT and INT telescopes at the Roque de los Muchachos Observatory (La Palma, Spain). These data are used to study the origin of the dwarf elliptical galaxy

  13. Galactic chemical evolution in hierarchical formation models - I. Early-type galaxies in the local Universe

    Arrigoni, Matías; Trager, Scott C.; Somerville, Rachel S.; Gibson, Brad K.

    We study the metallicities and abundance ratios of early-type galaxies in cosmological semi-analytic models (SAMs) within the hierarchical galaxy formation paradigm. To achieve this we implemented a detailed galactic chemical evolution model and can now predict abundances of individual elements for

  14. Galactic chemical evolution in hierarchical formation models : I. Early-type galaxies in the local Universe

    Arrigoni, Matias; Trager, Scott C.; Somerville, Rachel S.; Gibson, Brad K.

    2010-01-01

    We study the metallicities and abundance ratios of early-type galaxies in cosmological semi-analytic models (SAMs) within the hierarchical galaxy formation paradigm. To achieve this we implemented a detailed galactic chemical evolution model and can now predict abundances of individual elements for

  15. Enviromental Effects on Internal Color Gradients of Early-Type Galaxies

    La Barbera, F.; de Carvalho, R. R.; Gal, R. R.; Busarello, G.; Haines, C. P.; Mercurio, A.; Merluzzi, P.; Capaccioli, M.; Djorgovski, S. G.

    2007-05-01

    One of the most debated issues of observational and theoretical cosmology is that of how the environment affects the formation and evolution of galaxies. To gain new insight into this subject, we have derived surface photometry for a sample of 3,000 early-type galaxies belonging to 163 clusters with different richness, spanning a redshift range of 0.05 to 0.25. This large data-set is used to analyze how the color distribution inside galaxies depends on several parameters, such as cluster richness, local galaxy density, galaxy luminosity and redshift. We find that the internal color profile of galaxies strongly depends on the environment where galaxies reside. Galaxies in poor and rich clusters are found to follow two distinct trends in the color gradient vs. redshift diagram, with color gradients beeing less steep in rich rather than in poor clusters. No dependence of color gradients on galaxy luminosity is detected both for poor and rich clusters. We find that color gradients strongly depend on local galaxy density, with more shallow gradients in high density regions. Interestingly, this result holds only for low richness clusters, with color gradients of galaxies in rich clusters showing no dependence on local galaxy density. Our results support a reasonable picture whereby young early-type galaxies form in a dissipative collapse process, and then undergo increased (either major or minor) merging activity in richer rather than in poor clusters.

  16. THE SLOW DEATH (OR REBIRTH?) OF EXTENDED STAR FORMATION IN z ∼ 0.1 GREEN VALLEY EARLY-TYPE GALAXIES

    Fang, Jerome J.; Faber, S. M.; Salim, Samir; Graves, Genevieve J.; Rich, R. Michael

    2012-01-01

    UV observations in the local universe have uncovered a population of early-type galaxies with UV flux consistent with low-level recent or ongoing star formation. Understanding the origin of such star formation remains an open issue. We present resolved UV-optical photometry of a sample of 19 Sloan Digital Sky Survey (SDSS) early-type galaxies at z ∼ 0.1 drawn from the sample originally selected by Salim and Rich to lie in the bluer part of the green valley in the UV-optical color-magnitude diagram as measured by the Galaxy Evolution Explorer (GALEX). Utilizing high-resolution Hubble Space Telescope (HST) far-UV imaging provides unique insight into the distribution of UV light in these galaxies, which we call ''extended star-forming early-type galaxies'' (ESF-ETGs) because of extended UV emission that is indicative of recent star formation. The UV-optical color profiles of all ESF-ETGs show red centers and blue outer parts. Their outer colors require the existence of a significant underlying population of older stars in the UV-bright regions. An analysis of stacked SDSS spectra reveals weak LINER-like emission in their centers. Using a cross-matched SDSS DR7/GALEX GR6 catalog, we search for other green valley galaxies with similar properties to these ESF-ETGs and estimate that ≈13% of dust-corrected green valley galaxies of similar stellar mass and UV-optical color are likely ESF-candidates, i.e., ESF-ETGs are not rare. Our results are consistent with star formation that is gradually declining in existing disks, i.e., the ESF-ETGs are evolving onto the red sequence for the first time, or with rejuvenated star formation due to accreted gas in older disks provided that the gas does not disrupt the structure of the galaxy and the resulting star formation is not too recent and bursty. ESF-ETGs may typify an important subpopulation of galaxies that can linger in the green valley for up to several Gyrs, based on their resemblance to nearby gas-rich green valley

  17. Initial mass function for early-type stars in starburst galaxies

    Sekiguchi, K.; Anderson, K.S.

    1987-01-01

    The IMF slope of early-type stars in starburst galaxies is investigated using IUE observations and a technique that utilizes mass-linewidth relations for early-type stars. Fourteen low-resolution IUE spectra of eight starburst galaxies and three H II region galaxies are used to obtain line-strength ratios Si IV(1400 A)/C IV(1550 A). These are compared to model line ratios, and indicate that the average IMF slope for OB stars in these intense star-formation regions is appreciably flatter than that of the solar neighborhood. 46 references

  18. The hot and cold interstellar matter of early type galaxies and their radio emission

    Kim, Dongwoo; Fabbiano, G.

    1990-01-01

    Over the last few years, the knowledge of the interstellar matter (ISM) of early type galaxies has increased dramatically. Many early type galaxies are now known to have ISM in three different phases: cold (neutral hydrogen (HI), dust and molecular material), warm (ionized) and hot (S-ray emitting) gas. Early type galaxies have smaller masses of cold ISM (10 to the 7th power - 10 to the 8th power solar mass; Jura et al. 1987) than later type spiral galaxies, while they have far more hot gas (10 to the 9th power - 10 to the tenth power solar mass; Forman et al. 1985, Canizares et al. 1987). In order to understand the relationship between the different phases of the ISM and the role of the ISM in fueling radio continuum sources and star formation, researchers compared observational data from a wide range of wavelengths

  19. The hELENa project - I. Stellar populations of early-type galaxies linked with local environment and galaxy mass

    Sybilska, A.; Lisker, T.; Kuntschner, H.; Vazdekis, A.; van de Ven, G.; Peletier, R.; Falcón-Barroso, J.; Vijayaraghavan, R.; Janz, J.

    2017-01-01

    We present the first in a series of papers in T$h$e role of $E$nvironment in shaping $L$ow-mass $E$arly-type $N$earby g$a$laxies (hELENa) project. In this paper we combine our sample of 20 low-mass early types (dEs) with 258 massive early types (ETGs) from the ATLAS$^{\\mathrm{3D}}$ survey - all observed with the SAURON integral field unit (IFU) - to investigate early-type galaxies' stellar population scaling relations and the dependence of the population properties on local environment, exten...

  20. Isolated Early-type Galaxies in the 2dFGRS

    Fuse, Christopher R.; Lamir, C.

    2014-01-01

    Isolated galaxies are systems that have experienced limited external perturbations, thus the properties of these galaxies are largely due to internal processes. The features of isolated early-type galaxies (IEGs) provide a baseline from which to compare early-type systems residing in higher-density environments. We use the Two-Degree Field Galaxy Redshift Survey (2dFGRS) and the NASA Extragalactic Database (NED) to identify IEGs in the nearby universe. Search criteria in the 2dFGRS were chosen to insure that the IEGs have remained separated from neighboring galaxies for the majority of their lifetimes. Isolated galaxies are chosen utilizing a minimum projected physical separation of 1 Mpc from any neighboring non-dwarf galaxy brighter than Mb = -16.5 mags. A minimum redshift separation of 350 km/s between a candidate galaxy and a neighboring was imposed to further insure the candidate’s isolation. Early results of the search for isolated early-type galaxies in the southern sky are presented.

  1. Cosmological parameter constraints from galaxy-galaxy lensing and galaxy clustering with the SDSS DR7

    Mandelbaum, Rachel; Slosar, Anže; Baldauf, Tobias; Seljak, Uroš; Hirata, Christopher M.; Nakajima, Reiko; Reyes, Reinabelle; Smith, Robert E.

    2013-06-01

    Recent studies have shown that the cross-correlation coefficient between galaxies and dark matter is very close to unity on scales outside a few virial radii of galaxy haloes, independent of the details of how galaxies populate dark matter haloes. This finding makes it possible to determine the dark matter clustering from measurements of galaxy-galaxy weak lensing and galaxy clustering. We present new cosmological parameter constraints based on large-scale measurements of spectroscopic galaxy samples from the Sloan Digital Sky Survey (SDSS) data release 7. We generalize the approach of Baldauf et al. to remove small-scale information (below 2 and 4 h-1 Mpc for lensing and clustering measurements, respectively), where the cross-correlation coefficient differs from unity. We derive constraints for three galaxy samples covering 7131 deg2, containing 69 150, 62 150 and 35 088 galaxies with mean redshifts of 0.11, 0.28 and 0.40. We clearly detect scale-dependent galaxy bias for the more luminous galaxy samples, at a level consistent with theoretical expectations. When we vary both σ8 and Ωm (and marginalize over non-linear galaxy bias) in a flat Λ cold dark matter model, the best-constrained quantity is σ8(Ωm/0.25)0.57 = 0.80 ± 0.05 (1σ, stat. + sys.), where statistical and systematic errors (photometric redshift and shear calibration) have comparable contributions, and we have fixed ns = 0.96 and h = 0.7. These strong constraints on the matter clustering suggest that this method is competitive with cosmic shear in current data, while having very complementary and in some ways less serious systematics. We therefore expect that this method will play a prominent role in future weak lensing surveys. When we combine these data with Wilkinson Microwave Anisotropy Probe 7-year (WMAP7) cosmic microwave background (CMB) data, constraints on σ8, Ωm, H0, wde and ∑mν become 30-80 per cent tighter than with CMB data alone, since our data break several parameter

  2. The Halo Boundary of Galaxy Clusters in the SDSS

    Baxter, Eric; Jain, Bhuvnesh; Sheth, Ravi K. [Center for Particle Cosmology, Department of Physics, University of Pennsylvania, Philadelphia, PA 19104 (United States); Chang, Chihway; Kravtsov, Andrey [Kavli Institute for Cosmological Physics, The University of Chicago, Chicago, IL 60637 (United States); Adhikari, Susmita; Dalal, Neal [Department of Astronomy, University of Illinois at Urbana-Champaign, Champaign, IL 61801 (United States); More, Surhud [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Tokyo Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8583 (Japan); Rozo, Eduardo [Department of Physics, University of Arizona, Tucson, AZ 85721 (United States); Rykoff, Eli, E-mail: ebax@sas.upenn.edu [Kavli Institute for Particle Astrophysics and Cosmology, P.O. Box 2450, Stanford University, Stanford, CA 94305 (United States)

    2017-05-20

    Analytical models and simulations predict a rapid decline in the halo density profile associated with the transition from the “infalling” regime outside the halo to the “collapsed” regime within the halo. Using data from SDSS, we explore evidence for such a feature in the density profiles of galaxy clusters using several different approaches. We first estimate the steepening of the outer galaxy density profile around clusters, finding evidence for truncation of the halo profile. Next, we measure the galaxy density profile around clusters using two sets of galaxies selected on color. We find evidence of an abrupt change in galaxy colors that coincides with the location of the steepening of the density profile. Since galaxies that have completed orbits within the cluster are more likely to be quenched of star formation and thus appear redder, this abrupt change in galaxy color can be associated with the transition from single-stream to multi-stream regimes. We also use a standard model comparison approach to measure evidence for a “splashback”-like feature, but find that this approach is very sensitive to modeling assumptions. Finally, we perform measurements using an independent cluster catalog to test for potential systematic errors associated with cluster selection. We identify several avenues for future work: improved understanding of the small-scale galaxy profile, lensing measurements, identification of proxies for the halo accretion rate, and other tests. With upcoming data from the DES, KiDS, and HSC surveys, we can expect significant improvements in the study of halo boundaries.

  3. The Halo Boundary of Galaxy Clusters in the SDSS

    Baxter, Eric; Jain, Bhuvnesh; Sheth, Ravi K.; Chang, Chihway; Kravtsov, Andrey; Adhikari, Susmita; Dalal, Neal; More, Surhud; Rozo, Eduardo; Rykoff, Eli

    2017-01-01

    Analytical models and simulations predict a rapid decline in the halo density profile associated with the transition from the “infalling” regime outside the halo to the “collapsed” regime within the halo. Using data from SDSS, we explore evidence for such a feature in the density profiles of galaxy clusters using several different approaches. We first estimate the steepening of the outer galaxy density profile around clusters, finding evidence for truncation of the halo profile. Next, we measure the galaxy density profile around clusters using two sets of galaxies selected on color. We find evidence of an abrupt change in galaxy colors that coincides with the location of the steepening of the density profile. Since galaxies that have completed orbits within the cluster are more likely to be quenched of star formation and thus appear redder, this abrupt change in galaxy color can be associated with the transition from single-stream to multi-stream regimes. We also use a standard model comparison approach to measure evidence for a “splashback”-like feature, but find that this approach is very sensitive to modeling assumptions. Finally, we perform measurements using an independent cluster catalog to test for potential systematic errors associated with cluster selection. We identify several avenues for future work: improved understanding of the small-scale galaxy profile, lensing measurements, identification of proxies for the halo accretion rate, and other tests. With upcoming data from the DES, KiDS, and HSC surveys, we can expect significant improvements in the study of halo boundaries.

  4. MASSIVE GALAXIES ARE LARGER IN DENSE ENVIRONMENTS: ENVIRONMENTAL DEPENDENCE OF MASS–SIZE RELATION OF EARLY-TYPE GALAXIES

    Yoon, Yongmin; Im, Myungshin; Kim, Jae-Woo, E-mail: yymx2@astro.snu.ac.kr, E-mail: mim@astro.snu.ac.kr [Center for the Exploration of the Origin of the Universe (CEOU), Astronomy Program, Department of Physics and Astronomy, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 151-742 (Korea, Republic of)

    2017-01-01

    Under the Λ cold dark matter (ΛCDM) cosmological models, massive galaxies are expected to be larger in denser environments through frequent hierarchical mergers with other galaxies. Yet, observational studies of low-redshift early-type galaxies have shown no such trend, standing as a puzzle to solve during the past decade. We analyzed 73,116 early-type galaxies at 0.1 ≤  z  < 0.15, adopting a robust nonparametric size measurement technique and extending the analysis to many massive galaxies. We find for the first time that local early-type galaxies heavier than 10{sup 11.2} M {sub ⊙} show a clear environmental dependence in mass–size relation, in such a way that galaxies are as much as 20%–40% larger in the densest environments than in underdense environments. Splitting the sample into the brightest cluster galaxies (BCGs) and non-BCGs does not affect the result. This result agrees with the ΛCDM cosmological simulations and suggests that mergers played a significant role in the growth of massive galaxies in dense environments as expected in theory.

  5. The dark side of galaxy colour: evidence from new SDSS measurements of galaxy clustering and lensing

    Hearin, Andrew P.; Watson, Douglas F.; Becker, Matthew R.; Reyes, Reinabelle; Berlind, Andreas A.; Zentner, Andrew R.

    2014-10-01

    The age-matching model has recently been shown to predict correctly the luminosity L and g - r colour of galaxies residing within dark matter haloes. The central tenet of the model is intuitive: older haloes tend to host galaxies with older stellar populations. In this paper, we demonstrate that age matching also correctly predicts the g - r colour trends exhibited in a wide variety of statistics of the galaxy distribution for stellar mass M* threshold samples. In particular, we present new Sloan Digital Sky Survey (SDSS) measurements of galaxy clustering and the galaxy-galaxy lensing signal ΔΣ as a function of M* and g - r colour, and show that age matching exhibits remarkable agreement with these and other statistics of low-redshift galaxies. In so doing, we also demonstrate good agreement between the galaxy-galaxy lensing observed by SDSS and the ΔΣ signal predicted by abundance matching, a new success of this model. We describe how age matching is a specific example of a larger class of conditional abundance matching models (CAM), a theoretical framework we introduce here for the first time. CAM provides a general formalism to study correlations at fixed mass between any galaxy property and any halo property. The striking success of our simple implementation of CAM suggests that this technique has the potential to describe the same set of data as alternative models, but with a dramatic reduction in the required number of parameters. CAM achieves this reduction by exploiting the capability of contemporary N-body simulations to determine dark matter halo properties other than mass alone, which distinguishes our model from conventional approaches to the galaxy-halo connection.

  6. Kinematics and stellar populations of 17 dwarf early-type galaxies

    Thomas, D.; Bender, R.; Hopp, U.; Maraston, C.; Greggio, L.

    2002-01-01

    We present kinematics and stellar population properties of 17 dwarf early-type galaxies in the luminosity range -14> M_B> -19. Our sample fills the gap between the intensively studied giant elliptical and Local Group dwarf spheroidal galaxies. The dwarf ellipticals of the present sample have constant velocity dispersion profiles within their effective radii and do not show significant rotation, hence are clearly anisotropic. The dwarf lenticulars, instead, rotate faster and are, at least part...

  7. GLOBULAR CLUSTER POPULATIONS: FIRST RESULTS FROM S{sup 4}G EARLY-TYPE GALAXIES

    Zaritsky, Dennis [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Aravena, Manuel [Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Avenida Ejército 441, Santiago (Chile); Athanassoula, E.; Bosma, Albert [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Comerón, Sébastien; Laine, Jarkko; Laurikainen, Eija; Salo, Heikki [Astronomy Division, Department of Physics, P.O. Box 3000, FI-90014 University of Oulu (Finland); Elmegreen, Bruce G. [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Erroz-Ferrer, Santiago; Knapen, Johan H. [Instituto de Astrofísica de Canarias, Vía Lácteas, E-38205 La Laguna (Spain); Gadotti, Dimitri A.; Muñoz-Mateos, Juan Carlos [European Southern Observatory, Casilla 19001, Santiago 19 (Chile); Hinz, Joannah L. [MMT Observatory, P.O. Box 210065, Tucson, AZ 85721 (United States); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Holwerda, Benne [Leiden Observatory, University of Leiden, Niels Bohrweg 4, NL-2333 Leiden (Netherlands); Sheth, Kartik, E-mail: dennis.zaritsky@gmail.com [National Radio Astronomy Observatory/NAASC, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

    2015-02-01

    Using 3.6 μm images of 97 early-type galaxies, we develop and verify methodology to measure globular cluster populations from the S{sup 4}G survey images. We find that (1) the ratio, T {sub N}, of the number of clusters, N {sub CL}, to parent galaxy stellar mass, M {sub *}, rises weakly with M {sub *} for early-type galaxies with M {sub *} > 10{sup 10} M {sub ☉} when we calculate galaxy masses using a universal stellar initial mass function (IMF) but that the dependence of T {sub N} on M {sub *} is removed entirely once we correct for the recently uncovered systematic variation of IMF with M {sub *}; and (2) for M {sub *} < 10{sup 10} M {sub ☉}, there is no trend between N {sub CL} and M {sub *}, the scatter in T {sub N} is significantly larger (approaching two orders of magnitude), and there is evidence to support a previous, independent suggestion of two families of galaxies. The behavior of N {sub CL} in the lower-mass systems is more difficult to measure because these systems are inherently cluster-poor, but our results may add to previous evidence that large variations in cluster formation and destruction efficiencies are to be found among low-mass galaxies. The average fraction of stellar mass in clusters is ∼0.0014 for M {sub *} > 10{sup 10} M {sub ☉} and can be as large as ∼0.02 for less massive galaxies. These are the first results from the S{sup 4}G sample of galaxies and will be enhanced by the sample of early-type galaxies now being added to S{sup 4}G and complemented by the study of later-type galaxies within S{sup 4}G.

  8. Dark-Matter Content of Early-Type Galaxies with Planetary Nebulae

    Napolitano, N.R.; Romanowsky, A.J.; Coccato, L; Capaccioli, M.; Douglas, N.G.; Noordermeer, E.; Merrifield, M.R.; Kuijken, K.; Arnaboldi, M.; Gerhard, O.; Freeman, K.C.; De Lorenzi, F.; Das, P.

    2007-01-01

    Abstract. We examine the dark matter properties of nearby early-type galaxies using plane- tary nebulae (PNe) as mass probes. We have designed a specialised instrument, the Planetary Nebula Spectrograph (PN.S) operating at the William Herschel telescope, with the purpose of measuring PN velocities

  9. The kinematic properties of dwarf early-type galaxies in the Virgo cluster

    Toloba, E.; Boselli, A.; Peletier, R. F.; Gorgas, J.; Zapatero Osorio, M.R.; Gorgas, J.; Maíz Apellániz, J.; Pardo, J.R.; Gil de Paz, A.

    We present new medium resolution kinematic data for a sample of 21 dwarf early-type galaxies (dEs) mainly in the Virgo cluster. These data are used to study the origin of dEs inhabiting clusters. Within them we detect two populations: half of the sample (52%) are rotationally supported and the other

  10. The star-formation histories of early-type galaxies from ATLAS3D

    McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Cappellari, Michele; Crocker, Alison F.; Davies, Roger L.; Davis, Tim A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Rafaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nic; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    We present an exploration of the integrated stellar populations of early-type galaxies (ETGs) from the ATLAS3D survey. We use two approaches: firstly the application of line-indices interpreted through single stellar population (SSP) models, which provide a single value of age, metallicity and

  11. The kinematic properties of dwarf early-type galaxies in the Virgo cluster

    Toloba, E.; Boselli, A.; Peletier, R. F.; Gorgas, J.; Zapatero Osorio, M.R.; Gorgas, J.; Maíz Apellániz, J.; Pardo, J.R.; Gil de Paz, A.

    2011-01-01

    We present new medium resolution kinematic data for a sample of 21 dwarf early-type galaxies (dEs) mainly in the Virgo cluster. These data are used to study the origin of dEs inhabiting clusters. Within them we detect two populations: half of the sample (52%) are rotationally supported and the other

  12. STRUCTURAL EVOLUTION OF EARLY-TYPE GALAXIES TO z = 2.5 IN CANDELS

    Chang, Yu-Yen; Van der Wel, Arjen; Rix, Hans-Walter; Holden, Bradford; Faber, S. M.; Mozena, Mark; Guo Yicheng; Kocevski, Dale D.; Bell, Eric F.; McGrath, Elizabeth J.; Wuyts, Stijn; Häussler, Boris; Barden, Marco; Ferguson, Henry C.; Grogin, Norman A.; Koekemoer, Anton M.; Huang, Kuang-Han; Galametz, Audrey; Dekel, Avishai; Hathi, Nimish P.

    2013-01-01

    Projected axis ratio measurements of 880 early-type galaxies at redshifts 1 1 early-type galaxies show a variety of intrinsic shapes; even at a fixed mass, the projected axis ratio distributions cannot be explained by the random projection of a set of galaxies with very similar intrinsic shapes. However, a two-population model for the intrinsic shapes, consisting of a triaxial, fairly round population, combined with a flat (c/a ∼ 0.3) oblate population, adequately describes the projected axis ratio distributions of both present-day and z > 1 early-type galaxies. We find that the proportion of oblate versus triaxial galaxies depends both on the galaxies' stellar mass, and—at a given mass—on redshift. For present-day and z 1, this trend is much weaker over the mass range explored here (10 10 * /M ☉ 11 ), because the oblate fraction among massive (M * ∼ 10 11 M ☉ ) was much higher in the past: 0.59 ± 0.10 at z > 1, compared to 0.20 ± 0.02 at z ∼ 0.1. When combined with previous findings that the number density and sizes of early-type galaxies substantially increase over the same redshift range, this can be explained by the gradual emergence of merger-produced elliptical galaxies, at the expense of the destruction of pre-existing disks that were common among their high-redshift progenitors. In contrast, the oblate fraction among low-mass early-type galaxies (log (M * /M ☉ ) 1 to 0.72 ± 0.06 at z = 0. We speculate that this lower incidence of disks at early cosmic times can be attributed to two factors: low-mass, star-forming progenitors at z > 1 were not settled into stable disks to the same degree as at later cosmic times, and the stripping of gas from star-forming disk galaxies in dense environments is an increasingly important process at lower redshifts

  13. SDSS-IV MaNGA: Spatially resolved star formation histories in galaxies as a function of galaxy mass and type

    Goddard, D.; Thomas, D.; Maraston, C.; Westfall, K.; Etherington, J.; Riffel, R.; Mallmann, N. D.; Zheng, Z.; Argudo-Fernández, M.; Lian, J.; Bershady, M.; Bundy, K.; Drory, N.; Law, D.; Yan, R.; Wake, D.; Weijmans, A.; Bizyaev, D.; Brownstein, J.; Lane, R. R.; Maiolino, R.; Masters, K.; Merrifield, M.; Nitschelm, C.; Pan, K.; Roman-Lopes, A.; Storchi-Bergmann, T.; Schneider, D. P.

    2017-04-01

    We study the internal gradients of stellar population properties within 1.5 Re for a representative sample of 721 galaxies, with stellar masses ranging between 109 M⊙ and 1011.5 M⊙ from the SDSS-IV MaNGA Integral-Field-Unit survey. Through the use of our full spectral fitting code firefly, we derive light- and mass-weighted stellar population properties and their radial gradients, as well as full star formation and metal enrichment histories. We also quantify the impact that different stellar population models and full spectral fitting routines have on the derived stellar population properties and the radial gradient measurements. In our analysis, we find that age gradients tend to be shallow for both early-type and late-type galaxies. Mass-weighted age gradients of early-types arepositive (˜0.09 dex/Re) pointing to 'outside-in' progression of star formation, while late-type galaxies have negative light-weighted age gradients (˜-0.11 dex/Re), suggesting an 'inside-out' formation of discs. We detect negative metallicity gradients in both early- and late-type galaxies, but these are significantly steeper in late-types, suggesting that the radial dependence of chemical enrichment processes and the effect of gas inflow and metal transport are far more pronounced in discs. Metallicity gradients of both morphological classes correlate with galaxy mass, with negative metallicity gradients becoming steeper with increasing galaxy mass. The correlation with mass is stronger for late-type galaxies, with a slope of d(∇[Z/H])/d(log M) ˜ -0.2 ± 0.05 , compared to d(∇[Z/H])/d(log M) ˜ -0.05 ± 0.05 for early-types. This result suggests that the merger history plays a relatively small role in shaping metallicity gradients of galaxies.

  14. THE ROLE OF MERGERS IN EARLY-TYPE GALAXY EVOLUTION AND BLACK HOLE GROWTH

    Schawinski, Kevin; Dowlin, Nathan; Urry, C. Megan; Thomas, Daniel; Edmondson, Edward

    2010-01-01

    Models of galaxy formation invoke the major merger of gas-rich progenitor galaxies as the trigger for significant phases of black hole growth and the associated feedback that suppresses star formation to create red spheroidal remnants. However, the observational evidence for the connection between mergers and active galactic nucleus (AGN) phases is not clear. We analyze a sample of low-mass early-type galaxies known to be in the process of migrating from the blue cloud to the red sequence via an AGN phase in the green valley. Using deeper imaging from Sloan Digital Sky Survey Stripe 82, we show that the fraction of objects with major morphological disturbances is high during the early starburst phase, but declines rapidly to the background level seen in quiescent early-type galaxies by the time of substantial AGN radiation several hundred Myr after the starburst. This observation empirically links the AGN activity in low-redshift early-type galaxies to a significant merger event in the recent past. The large time delay between the merger-driven starburst and the peak of AGN activity allows for the merger features to decay to the background and hence may explain the weak link between merger features and AGN activity in the literature.

  15. STRUCTURAL EVOLUTION OF EARLY-TYPE GALAXIES TO z = 2.5 IN CANDELS

    Chang, Yu-Yen; Van der Wel, Arjen; Rix, Hans-Walter [Max-Planck Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Holden, Bradford; Faber, S. M.; Mozena, Mark; Guo Yicheng; Kocevski, Dale D. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); McGrath, Elizabeth J. [Department of Physics and Astronomy, Colby College, Waterville, ME 04901 (United States); Wuyts, Stijn [Max-Planck-Institut fuer Extraterrestrische Physik, Postfach 1312, Giessenbachstr., D-85741 Garching (Germany); Haeussler, Boris [Schools of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Barden, Marco [Institute of Astro- and Particle Physics, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria); Ferguson, Henry C.; Grogin, Norman A.; Koekemoer, Anton M.; Huang, Kuang-Han [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Galametz, Audrey [INAF-Osservatorio di Roma, Via Frascati 33, I-00040 Monteporzio (Italy); Dekel, Avishai [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Hathi, Nimish P., E-mail: chang@mpia.de [Observatories of the Carnegie Institution for Science, Pasadena, CA (United States); and others

    2013-08-20

    Projected axis ratio measurements of 880 early-type galaxies at redshifts 1 < z < 2.5 selected from CANDELS are used to reconstruct and model their intrinsic shapes. The sample is selected on the basis of multiple rest-frame colors to reflect low star-formation activity. We demonstrate that these galaxies as an ensemble are dust-poor and transparent and therefore likely have smooth light profiles, similar to visually classified early-type galaxies. Similar to their present-day counterparts, the z > 1 early-type galaxies show a variety of intrinsic shapes; even at a fixed mass, the projected axis ratio distributions cannot be explained by the random projection of a set of galaxies with very similar intrinsic shapes. However, a two-population model for the intrinsic shapes, consisting of a triaxial, fairly round population, combined with a flat (c/a {approx} 0.3) oblate population, adequately describes the projected axis ratio distributions of both present-day and z > 1 early-type galaxies. We find that the proportion of oblate versus triaxial galaxies depends both on the galaxies' stellar mass, and-at a given mass-on redshift. For present-day and z < 1 early-type galaxies the oblate fraction strongly depends on galaxy mass. At z > 1, this trend is much weaker over the mass range explored here (10{sup 10} < M{sub *}/M{sub Sun} < 10{sup 11}), because the oblate fraction among massive (M{sub *} {approx} 10{sup 11} M{sub Sun }) was much higher in the past: 0.59 {+-} 0.10 at z > 1, compared to 0.20 {+-} 0.02 at z {approx} 0.1. When combined with previous findings that the number density and sizes of early-type galaxies substantially increase over the same redshift range, this can be explained by the gradual emergence of merger-produced elliptical galaxies, at the expense of the destruction of pre-existing disks that were common among their high-redshift progenitors. In contrast, the oblate fraction among low-mass early-type galaxies (log (M{sub *}/M{sub Sun }) < 10

  16. The X-Shooter Lens Survey - I. Dark matter domination and a Salpeter-type initial mass function in a massive early-type galaxy

    Spiniello, C.; Koopmans, L. V. E.; Trager, S. C.; Czoske, O.; Treu, T.

    2011-11-01

    We present the first results from the X-Shooter Lens Survey: an analysis of the massive early-type galaxy SDSS J1148+1930 at redshift z= 0.444. We combine its extended kinematic profile - derived from spectra obtained with X-Shooter on the European Southern Observatory Very Large Telescope - with strong gravitational lensing and multicolour information derived from Sloan Digital Sky Survey (SDSS) images. Our main results are as follows. (i) The luminosity-weighted stellar velocity dispersion is (≲Reff) = 352 ± 10 ± 16 km s-1, extracted from a rectangular aperture of 1.8 × 1.6 arcsec2 centred on the galaxy, more accurate and considerably lower than a previously published value of ˜450 km s-1. (ii) A single-component (stellar plus dark) mass model of the lens galaxy yields a logarithmic total-density slope of γ'= 1.72+0.05- 0.06 (68 per cent confidence level, CL; ?) within a projected radius of ˜2.16 arcsec. (iii) The projected stellar mass fraction, derived solely from the lensing and dynamical data, is f*(Salp(90 per cent CL and in some cases violate the total lensing-derived mass limit. We conclude that this very massive early-type galaxy is dark-matter-dominated inside one effective radius, consistent with the trend recently found from massive Sloan Lens ACS (SLACS) galaxies, with a total density slope shallower than isothermal and an IMF normalization consistent with Salpeter.

  17. Gas-rich dwarfs and accretion phenomena in early-type galaxies

    Silk, J.; Norman, C.

    1979-01-01

    Recent constraints on intergalactic H I clouds suggest that allowable accretion rates by several luminous early-type galaxies are too low to account for their observed H I content. We have therefore developed an alternative model, wherein gas-rich dwarf galaxies are accreted into galactic halos. This process is significant in groups of galaxies only when a sufficiently high density of gas-rich dwarfs (approx.30 Mpc -3 ) is present. The dwarf galaxy gas content plays a crucial role in enabling the galaxy to be trapped in the halo by interaction with a galactic wind or extensive gaseous corona. Gas stripping occurs, resulting in the formation of dwarf spheroidal systems that populate the outer halos of massive galaxies and in the injection of a system of clouds into the halo. If the clouds are initially confined by the pressure of the ambient halo medium, dissipation and continuing infall enable the clouds to accrete into the central regions of galaxies before becoming gravitationally unstable and presumably forming stars. Consequences of this scenario include the production of a radial abundance gradient and infall of adequate amounts of neutral gas to account for the observations of H I in early-type galaxies. This gas accretion rate is also sufficient to feed active nuclei and radio sources. An important cosmological implication of our model is that, because the characteristic time scale of a gas-rich dwarf galaxy to be accreted and lose its gas is comparable to a Hubble time, there many have been a far more extensive primordial distribution of such systems at earlier epochs. This implies that accretion rates were greatly enhanced at relatively recent epochs (z> or approx. =0.5) and could account both for the rapid cosmological evolution inferred for radio galaxies and quasars, and for the observed frequency of occurrence of quasar absorption-line systems

  18. The hELENa project - I. Stellar populations of early-type galaxies linked with local environment and galaxy mass

    Sybilska, A.; Lisker, T.; Kuntschner, H.; Vazdekis, A.; van de Ven, G.; Peletier, R.; Falcón-Barroso, J.; Vijayaraghavan, R.; Janz, J.

    2017-09-01

    We present the first in a series of papers in The role of Environment in shaping Low-mass Early-type Nearby galaxies (hELENa) project. In this paper, we combine our sample of 20 low-mass early types (dEs) with 258 massive early types (ETGs) from the ATLAS3D survey - all observed with the SAURON integral field unit - to investigate early-type galaxies' stellar population scaling relations and the dependence of the population properties on local environment, extended to the low-σ regime of dEs. The ages in our sample show more scatter at lower σ values, indicative of less massive galaxies being affected by the environment to a higher degree. The shape of the age-σ relations for cluster versus non-cluster galaxies suggests that cluster environment speeds up the placing of galaxies on the red sequence. While the scaling relations are tighter for cluster than for the field/group objects, we find no evidence for a difference in average population characteristics of the two samples. We investigate the properties of our sample in the Virgo cluster as a function of number density (rather than simple clustrocentric distance) and find that dE ages correlate with the local density such that galaxies in regions of lower density are younger, likely because they are later arrivals to the cluster or have experienced less pre-processing in groups, and consequently used up their gas reservoir more recently. Overall, dE properties correlate more strongly with density than those of massive ETGs, which was expected as less massive galaxies are more susceptible to external influences.

  19. The Sloan Lens ACS Survey. I. A large spectroscopically selected sample of massive early-type lens galaxies

    Bolton, AS; Burles, S; Koopmans, LVE; Treu, T; Moustakas, LA

    2006-01-01

    The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple

  20. Snapshot Survey of the Globular Cluster Populations of Isolated Early Type Galaxies

    Gregg, Michael

    2017-08-01

    We propose WFC3/UVIS snapshot observations of a sample of 75 isolated early type galaxiesresiding in cosmic voids or extremely low density regions. The primary aim is to usetheir globular cluster populations to reconstruct their evolutionary history, revealingif, how, and why void ellipticals differ from cluster ellipticals. The galaxies span arange of luminosities, providing a varied sample for comparison with the well-documentedglobular cluster populations in denser environments. This proposed WFC3 study of isolatedearly type galaxies breaks new ground by targeting a sample which has thus far receivedlittle attention, and, significantly, this will be the first such study with HST.Characterizing early type galaxies in voids and their GC systems promises to increase ourunderstanding of galaxy formation and evolution of galaxies in general because isolatedobjects are the best approximation to a control sample that we have for understanding theinfluence of environment on formation and evolution. Whether these isolated objects turnout to be identical to or distinct from counterparts in other regions of the Universe,they will supply insight into the formation and evolution of all galaxies. Parallel ACSimaging will help to characterize the near field environments of the sample.

  1. CONSTRAINTS ON FEEDBACK PROCESSES DURING THE FORMATION OF EARLY-TYPE GALAXIES

    Trevisan, M. [Departamento de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo/IAG, Sao Paulo (Brazil); Ferreras, I. [MSSL, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom); De La Rosa, I. G. [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); La Barbera, F. [INAF-Osservatorio Astronomico di Capodimonte, Napoli (Italy); De Carvalho, R. R., E-mail: trevisan@astro.iag.usp.br [Instituto Nacional de Pesquisas Espaciais/MCT, S. J. dos Campos (Brazil)

    2012-06-20

    Galaxies are found to obey scaling relations between a number of observables. These relations follow different trends at the low- and high-mass ends. The processes driving the curvature of scaling relations remain uncertain. In this Letter, we focus on the specific family of early-type galaxies, deriving the star formation histories of a complete sample of visually classified galaxies from Sloan Digital Sky Survey DR7 over the redshift range 0.01 < z < 0.025, covering a stellar mass interval from 10{sup 9} to 3 Multiplication-Sign 10{sup 11} M{sub Sun }. Our sample features the characteristic 'knee' in the surface brightness versus mass distribution at M{sub *} {approx} 3 Multiplication-Sign 10{sup 10} M{sub Sun} . We find a clear difference between the age and metallicity distributions of the stellar populations above and beyond this knee, which suggests a sudden transition from a constant, highly efficient mode of star formation in high-mass galaxies, gradually decreasing toward the low-mass end of the sample. At fixed mass, our early-type sample is more efficient in building up the stellar content at early times in comparison to the general population of galaxies, with half of the stars already in place by redshift z {approx} 2 for all masses. The metallicity-age trend in low-mass galaxies is not compatible with infall of metal-poor gas, suggesting instead an outflow-driven relation.

  2. Understanding the faint red galaxy population using large-scale clustering measurements from SDSS DR7

    Ross, Ashley; Tojeiro, Rita; Percival, Will

    2011-01-01

    We use data from the SDSS to investigate the evolution of the large-scale galaxy bias as a function of luminosity for red galaxies. We carefully consider correlation functions of galaxies selected from both photometric and spectroscopic data, and cross-correlations between them, to obtain multiple measurements of the large-scale bias. We find, for our most robust analyses, a strong increase in bias with luminosity for the most luminous galaxies, an intermediate regime where bias does not evol...

  3. The dark side of galaxy colour: evidence from new SDSS measurements of galaxy clustering and lensing

    Hearin, Andrew P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States). Fermilab Center for Particle Astrophysics; Watson, Douglas F. [Univ. of Chicago, IL (United States). Kavli Inst. for Cosmological Physics (KICP); Becker, Matthew R. [Univ. of Chicago, IL (United States). Kavli Inst. for Cosmological Physics (KICP); KICP, Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Reyes, Reinabelle [Univ. of Chicago, IL (United States). Kavli Inst. for Cosmological Physics (KICP); Berlind, Andreas A. [Vanderbilt Univ., Nashville, TN (United States). Dept. of Physics and Astronomy; Zentner, Andrew R. [Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT PACC), PA (United States)

    2014-08-12

    The age matching model has recently been shown to predict correctly the luminosity L and g-r color of galaxies residing within dark matter halos. The central tenet of the model is intuitive: older halos tend to host galaxies with older stellar populations. In this paper, we demonstrate that age matching also correctly predicts the g-r color trends exhibited in a wide variety of statistics of the galaxy distribution for stellar mass M* threshold samples. In particular, we present new measurements of the galaxy two-point correlation function and the galaxy-galaxy lensing signal as a function of M* and g-r color from the Sloan Digital Sky Survey, and show that age matching exhibits remarkable agreement with these and other statistics of low-redshift galaxies. In so doing, we also demonstrate good agreement between the galaxy-galaxy lensing observed by SDSS and the signal predicted by abundance matching, a new success of this model. We describe how age matching is a specific example of a larger class of Conditional Abundance Matching models (CAM), a theoretical framework we introduce here for the first time. CAM provides a general formalism to study correlations at fixed mass between any galaxy property and any halo property. The striking success of our simple implementation of CAM provides compelling evidence that this technique has the potential to describe the same set of data as alternative models, but with a dramatic reduction in the required number of parameters. CAM achieves this reduction by exploiting the capability of contemporary N-body simulations to determine dark matter halo properties other than mass alone, which distinguishes our model from conventional approaches to the galaxy-halo connection.

  4. HOMOGENEOUS UGRIZ PHOTOMETRY FOR ACS VIRGO CLUSTER SURVEY GALAXIES: A NON-PARAMETRIC ANALYSIS FROM SDSS IMAGING

    Chen, Chin-Wei; Cote, Patrick; Ferrarese, Laura; West, Andrew A.; Peng, Eric W.

    2010-01-01

    We present photometric and structural parameters for 100 ACS Virgo Cluster Survey (ACSVCS) galaxies based on homogeneous, multi-wavelength (ugriz), wide-field SDSS (DR5) imaging. These early-type galaxies, which trace out the red sequence in the Virgo Cluster, span a factor of nearly ∼10 3 in g-band luminosity. We describe an automated pipeline that generates background-subtracted mosaic images, masks field sources and measures mean shapes, total magnitudes, effective radii, and effective surface brightnesses using a model-independent approach. A parametric analysis of the surface brightness profiles is also carried out to obtain Sersic-based structural parameters and mean galaxy colors. We compare the galaxy parameters to those in the literature, including those from the ACSVCS, finding good agreement in most cases, although the sizes of the brightest, and most extended, galaxies are found to be most uncertain and model dependent. Our photometry provides an external measurement of the random errors on total magnitudes from the widely used Virgo Cluster Catalog, which we estimate to be σ(B T )∼ 0.13 mag for the brightest galaxies, rising to ∼ 0.3 mag for galaxies at the faint end of our sample (B T ∼ 16). The distribution of axial ratios of low-mass ( d warf ) galaxies bears a strong resemblance to the one observed for the higher-mass ( g iant ) galaxies. The global structural parameters for the full galaxy sample-profile shape, effective radius, and mean surface brightness-are found to vary smoothly and systematically as a function of luminosity, with unmistakable evidence for changes in structural homology along the red sequence. As noted in previous studies, the ugriz galaxy colors show a nonlinear but smooth variation over a ∼7 mag range in absolute magnitude, with an enhanced scatter for the faintest systems that is likely the signature of their more diverse star formation histories.

  5. Spectrophotometric Properties of E+A Galaxies in SDSS-IV MaNGA

    Marinelli, Mariarosa; Dudley, Raymond; Edwards, Kay; Gonzalez, Andrea; Johnson, Amalya; Kerrison, Nicole; Melchert, Nancy; Ojanen, Winonah; Weaver, Olivia; Liu, Charles; SDSS-IV MaNGA

    2018-01-01

    Quenched post-starburst galaxies, or E+A galaxies, represent a unique and informative phase in the evolution of galaxies. We used a qualitative rubric-based methodology, informed by the literature, to manually select galaxies from the SDSS-IV IFU survey Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) using the single-fiber spectra from the Sloan Digital Sky Survey Data Release 8. Of the 2,812 galaxies observed so far in MaNGA, we found 39 galaxies meeting our criteria for E+A classification. Spectral energy distributions of these 39 galaxies from the far-UV to the mid-infrared demonstrate a heterogeneity in our sample emerging in the infrared, indicating many distinct paths to visually similar optical spectra. We used SDSS-IV MaNGA Pipe3D data products to analyze stellar population ages, and found that 34 galaxies exhibited stellar populations that were older at 1 effective radius than at the center of the galaxy. Given that our sample was manually chosen based on E+A markers in the single-fiber spectra aimed at the center of each galaxy, our E+A galaxies may have only experienced their significant starbursts in the central region, with a disk of quenched or quenching material further outward. This work was supported by grants AST-1460860 from the National Science Foundation and SDSS FAST/SSP-483 from the Alfred P. Sloan Foundation to the CUNY College of Staten Island.

  6. SPIDER. IV. OPTICAL AND NEAR-INFRARED COLOR GRADIENTS IN EARLY-TYPE GALAXIES: NEW INSIGHT INTO CORRELATIONS WITH GALAXY PROPERTIES

    La Barbera, F.; De Carvalho, R. R.; De La Rosa, I. G.; Gal, R. R.; Swindle, R.; Lopes, P. A. A.

    2010-01-01

    We present an analysis of stellar population gradients in 4546 early-type galaxies (ETGs) with photometry in grizYHJK along with optical spectroscopy. ETGs were selected as bulge-dominated systems, displaying passive spectra within the SDSS fibers. A new approach is described which utilizes color information to constrain age and metallicity gradients. Defining an effective color gradient, ∇ * , which incorporates all of the available color indices, we investigate how ∇ * varies with galaxy mass proxies, i.e., velocity dispersion, stellar (M * ) and dynamical (M dyn ) masses, as well as age, metallicity, and [α/Fe]. ETGs with M dyn larger than 8.5 x 10 10 M sun have increasing age gradients and decreasing metallicity gradients with respect to mass, metallicity, and enhancement. We find that velocity dispersion and [α/Fe] are the main drivers of these correlations. ETGs with 2.5 x 10 10 M sun ≤ M dyn ≤ 8.5 x 10 10 M sun show no correlation of age, metallicity, and color gradients with respect to mass, although color gradients still correlate with stellar population parameters, and these correlations are independent of each other. In both mass regimes, the striking anti-correlation between color gradient and α-enhancement is significant at ∼5σ and results from the fact that metallicity gradient decreases with [α/Fe]. This anti-correlation may reflect the fact that star formation and metallicity enrichment are regulated by the interplay between the energy input from supernovae, and the temperature and pressure of the hot X-ray gas in ETGs. For all mass ranges, positive age gradients are associated with old galaxies (>5-7 Gyr). For galaxies younger than ∼5 Gyr, mostly at low mass, the age gradient tends to be anti-correlated with the Age parameter, with more positive gradients at younger ages.

  7. The TESIS Project: Revealing Massive Early-Type Galaxies at z > 1

    Saracco, P.; Longhetti, M.; Severgnini, P.; Della Ceca, R.; Braito, V.; Bender, R.; Drory, N.; Feulner, G.; Hopp, U.; Mannucci, F.; Maraston, C.

    How and when present-day massive early-type galaxies built up and what type of evolution has characterized their growth (star formation and/or merging) still remain open issues. The different competing scenarios of galaxy formation predict much different properties of early-type galaxies at z > 1. The "monolithic" collapse predicts that massive spheroids formed at high redshift (z > 2.5-3) and that their comoving density is constant at z 1, their comoving density decreases from z = 0 to z ~ 1.5 and they should experience their last burst of star formation at z 1 can be probed observationally once a well defined sample of massive early-types at z > 1 is available. We are constructing such a sample through a dedicated near-IR very low resolution (λ/Δλ≃50) spectroscopic survey (TNG EROs Spectroscopic Identification Survey, TESIS, [6]) of a complete sample of 30 bright (K < 18.5) Extremely Red Objects (EROs).

  8. THE EFFECT OF DRY MERGERS ON THE COLOR-MAGNITUDE RELATION OF EARLY-TYPE GALAXIES

    Skelton, Rosalind E.; Bell, Eric F.; Somerville, Rachel S.

    2009-01-01

    We investigate the effect of dry merging on the color-magnitude relation (CMR) of galaxies and find that the amount of merging predicted by a hierarchical model results in a red sequence that compares well with the observed low-redshift relation. A sample of ∼ 29,000 early-type galaxies selected from the Sloan Digital Sky Survey Data Release 6 shows that the bright end of the CMR has a shallower slope and smaller scatter than the faint end. This magnitude dependence is predicted by a simple toy model in which gas-rich mergers move galaxies onto a 'creation red sequence' (CRS) by quenching their star formation, and subsequent mergers between red, gas-poor galaxies (so-called 'dry' mergers) move galaxies along the relation. We use galaxy merger trees from a semianalytic model of galaxy formation to test the amplitude of this effect and find a change in slope at the bright end that brackets the observations, using gas fraction thresholds of 10%-30% to separate wet and dry mergers. A more realistic model that includes scatter in the CRS shows that dry merging decreases the scatter at the bright end. Contrary to previous claims, the small scatter in the observed CMR thus cannot be used to constrain the amount of dry merging.

  9. Host Galaxy Spectra and Consequences for SN Typing from the SDSS SN Survey

    Olmstead, Matthew D.; Brown, Peter J.; Sako, Masao; Bassett, Bruce; Bizyaev, Dmitry; Brinkmann, J.; Brownstein, Joel R.; Brewington, Howard; Campbell, Heather; D’Andrea, Chris B.; Dawson, Kyle S.; Ebelke, Garrett L.; Frieman, Joshua A.; Galbany, Lluís; Garnavich, Peter; Gupta, Ravi R.; Hlozek, Renee; Jha, Saurabh W.; Kunz, Martin; Lampeitl, Hubert; Malanushenko, Elena; Malanushenko, Viktor; Marriner, John; Miquel, Ramon; Montero-Dorta, Antonio D.; Nichol, Robert C.; Oravetz, Daniel J.; Pan, Kaike; Schneider, Donald P.; Simmons, Audrey E.; Smith, Mathew; Snedden, Stephanie A.

    2014-03-06

    We present the spectroscopy from 5254 galaxies that hosted supernovae (SNe) or other transient events in the Sloan Digital Sky Survey II (SDSS-II). Obtained during SDSS-I, SDSS-II, and the Baryon Oscillation Spectroscopic Survey (BOSS), this sample represents the largest systematic, unbiased, magnitude limited spectroscopic survey of supernova (SN) host galaxies. Using the host galaxy redshifts, we test the impact of photometric SN classification based on SDSS imaging data with and without using spectroscopic redshifts of the host galaxies. Following our suggested scheme, there are a total of 1166 photometrically classified SNe Ia when using a flat redshift prior and 1126 SNe Ia when the host spectroscopic redshift is assumed. For 1024 (87.8%) candidates classified as likely SNe Ia without redshift information, we find that the classification is unchanged when adding the host galaxy redshift. Using photometry from SDSS imaging data and the host galaxy spectra, we also report host galaxy properties for use in future nalysis of SN astrophysics. Finally, we investigate the differences in the interpretation of the light curve properties with and without knowledge of the redshift. When using the SALT2 light curve fitter, we find a 21% increase in the number of fits that converge when using the spectroscopic redshift. Without host galaxy redshifts, we find that SALT2 light curve fits are systematically biased towards lower photometric redshift estimates and redder colors in the limit of low signal-to-noise data. The general improvements in performance of the light curve fitter and the increased diversity of the host galaxy sample highlights the importance of host galaxy spectroscopy for current photometric SN surveys such as the Dark Energy Survey and future surveys such as the Large Synoptic Survey Telescope.

  10. Host galaxy spectra and consequences for supernova typing from the SDSS SN survey

    Olmstead, Matthew D.; Brown, Peter J.; Brownstein, Joel R.; Dawson, Kyle S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Sako, Masao; Gupta, Ravi R. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Bassett, Bruce; Kunz, Martin [African Institute for Mathematical Sciences, 6 Melrose Road, Muizenberg, 7945 (South Africa); Bizyaev, Dmitry; Brinkmann, J.; Brewington, Howard; Ebelke, Garrett L. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Campbell, Heather [Institute of Astronomy, Madingley Road, Cambridge CB4 0HA (United Kingdom); D' Andrea, Chris B.; Lampeitl, Hubert [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Frieman, Joshua A. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Galbany, Lluís [Institut de Física d' Altes Energies, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona) (Spain); Garnavich, Peter [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Hlozek, Renee [Department of Astrophysics, Peyton Hall, 4 Ivy Lane, Princeton, NJ 08544 (United States); Jha, Saurabh W., E-mail: olmstead@physics.utah.edu [Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); and others

    2014-04-01

    We present the spectroscopy from 5254 galaxies that hosted supernovae (SNe) or other transient events in the Sloan Digital Sky Survey II (SDSS-II). Obtained during SDSS-I, SDSS-II, and the Baryon Oscillation Spectroscopic Survey, this sample represents the largest systematic, unbiased, magnitude limited spectroscopic survey of SN host galaxies. Using the host galaxy redshifts, we test the impact of photometric SN classification based on SDSS imaging data with and without using spectroscopic redshifts of the host galaxies. Following our suggested scheme, there are a total of 1166 photometrically classified SNe Ia when using a flat redshift prior and 1126 SNe Ia when the host spectroscopic redshift is assumed. For 1024 (87.8%) candidates classified as likely SNe Ia without redshift information, we find that the classification is unchanged when adding the host galaxy redshift. Using photometry from SDSS imaging data and the host galaxy spectra, we also report host galaxy properties for use in future analysis of SN astrophysics. Finally, we investigate the differences in the interpretation of the light curve properties with and without knowledge of the redshift. Without host galaxy redshifts, we find that SALT2 light curve fits are systematically biased toward lower photometric redshift estimates and redder colors in the limit of low signal-to-noise data. The general improvements in performance of the light curve fitter and the increased diversity of the host galaxy sample highlights the importance of host galaxy spectroscopy for current photometric SN surveys such as the Dark Energy Survey and future surveys such as the Large Synoptic Survey Telescope.

  11. The SDSS Discovery of a Strongly Lensed Post-Starburst Galaxy at z=0.766

    Shin, Min-Su; Strauss, Michael A.; Oguri, Masamune; Inada, Naohisa; Falco, Emilio E.; Broadhurst, Tom; Gunn, James E.

    2008-09-30

    We present the first result of a survey for strong galaxy-galaxy lenses in Sloan Digital Sky Survey (SDSS) images. SDSS J082728.70+223256.4 was selected as a lensing candidate using selection criteria based on the color and positions of objects in the SDSS photometric catalog. Follow-up imaging and spectroscopy showed this object to be a lensing system. The lensing galaxy is an elliptical at z = 0.349 in a galaxy cluster. The lensed galaxy has the spectrum of a post-starburst galaxy at z = 0.766. The lensing galaxy has an estimated mass of {approx} 1.2 x 10{sup 12} M{sub {circle_dot}} and the corresponding mass to light ratio in the B-band is {approx} 26 M{sub {circle_dot}}/L{sub {circle_dot}} inside 1.1 effective radii of the lensing galaxy. Our study shows how catalogs drawn from multi-band surveys can be used to find strong galaxy-galaxy lenses having multiple lens images. Our strong lensing candidate selection based on photometry-only catalogs will be useful in future multi-band imaging surveys such as SNAP and LSST.

  12. Low dark matter content of the nearby early-type galaxy NGC 821

    Samurović S.

    2014-01-01

    Full Text Available In this paper we analyze the kinematics and dynamics of the nearby early-type galaxy NGC 821 based on its globular clusters (GCs and planetary nebulae (PNe. We use PNe and GCs to extract the kinematics of NGC 821 which is then used for the dynamical modelling based on the Jeans equation. We apply the Jeans equation using the Newtonian mass-follows-light approach assuming constant mass-to-light ratio and find that using such an approach we can successfully fit the kinematic data. The inferred constant mass-to-light ratio, 4:2 < M=LB < 12:4 present throughout the whole galaxy, implies the lack of significant amount of dark matter. We also used three different MOND approaches and found that we can fit the kinematic data without the need for additional, dark, component. [Projekat Ministarstva nauke Republike Srbije, br. 176021: Visible and invisible matter in nearby galaxies: theory and observations

  13. A GMBCG galaxy cluster catalog of 55,880 rich clusters from SDSS DR7

    Hao, Jiangang; McKay, Timothy A.; Koester, Benjamin P.; Rykoff, Eli S.; Rozo, Eduardo; Annis, James; Wechsler, Risa H.; Evrard, August; Siegel, Seth R.; Becker, Matthew; Busha, Michael; /Fermilab /Michigan U. /Chicago U., Astron. Astrophys. Ctr. /UC, Santa Barbara /KICP, Chicago /KIPAC, Menlo Park /SLAC /Caltech /Brookhaven

    2010-08-01

    We present a large catalog of optically selected galaxy clusters from the application of a new Gaussian Mixture Brightest Cluster Galaxy (GMBCG) algorithm to SDSS Data Release 7 data. The algorithm detects clusters by identifying the red sequence plus Brightest Cluster Galaxy (BCG) feature, which is unique for galaxy clusters and does not exist among field galaxies. Red sequence clustering in color space is detected using an Error Corrected Gaussian Mixture Model. We run GMBCG on 8240 square degrees of photometric data from SDSS DR7 to assemble the largest ever optical galaxy cluster catalog, consisting of over 55,000 rich clusters across the redshift range from 0.1 < z < 0.55. We present Monte Carlo tests of completeness and purity and perform cross-matching with X-ray clusters and with the maxBCG sample at low redshift. These tests indicate high completeness and purity across the full redshift range for clusters with 15 or more members.

  14. UV SEDs of early-type cluster galaxies: a new look at the UV upturn

    Ali, S. S.; Bremer, M. N.; Phillipps, S.; De Propris, R.

    2018-05-01

    Using GALEX, Ultraviolet Optical Telescope (UVOT), and optical photometry, we explore the prevalence and strength of the Ultraviolet (UV) upturn in the spectra of quiescent early-type galaxies in several nearby clusters. Even for galaxies with completely passive optical colours, there is a large spread in vacuum UV colour consistent with almost all having some UV upturn component. Combining GALEX and UVOT data below 3000 Å, we generate for the first time comparatively detailed UV spectral energy distributions for Coma cluster galaxies. Fitting the UV upturn component with a blackbody, 26 of these show a range of characteristic temperatures (10 000-21 000K) for the UV upturn population. Assuming a single temperature to explain GALEX-optical colours could underestimate the fraction of galaxies with UV upturns and mis-classify some as systems with residual star formation. The UV upturn phenomenon is not an exclusive feature found only in giant galaxies; we identify galaxies with similar (or even bluer) FUV - V colours to the giants with upturns over a range of fainter luminosities. The temperature and strength of the UV upturn are correlated with galaxy mass. Under the plausible hypothesis that the sources of the UV upturn are blue horizontal branch stars, the most likely mechanism for this is the presence of a substantial (between 4 per cent and 20 per cent) Helium-rich (Y > 0.3) population of stars in these galaxies, potentially formed at z ˜ 4 and certainly at z > 2; this plausibly sets a lower limit of {˜ } {0.3- 0.8} × 10^{10} M⊙ to the in situ stellar mass of ˜L* galaxies at this redshift.

  15. CENTRAL DARK MATTER TRENDS IN EARLY-TYPE GALAXIES FROM STRONG LENSING, DYNAMICS, AND STELLAR POPULATIONS

    Tortora, C.; Jetzer, P.; Napolitano, N. R.; Romanowsky, A. J.

    2010-01-01

    We analyze the correlations between central dark matter (DM) content of early-type galaxies and their sizes and ages, using a sample of intermediate-redshift (z ∼ 0.2) gravitational lenses from the SLACS survey, and by comparing them to a larger sample of z ∼ 0 galaxies. We decompose the deprojected galaxy masses into DM and stellar components using combinations of strong lensing, stellar dynamics, and stellar populations modeling. For a given stellar mass, we find that for galaxies with larger sizes, the DM fraction increases and the mean DM density decreases, consistently with the cuspy halos expected in cosmological formation scenarios. The DM fraction also decreases with stellar age, which can be partially explained by the inverse correlation between size and age. The residual trend may point to systematic dependencies on formation epoch of halo contraction or stellar initial mass functions. These results are in agreement with recent findings based on local galaxies by Napolitano et al. and suggest negligible evidence of galaxy evolution over the last ∼2.5 Gyr other than passive stellar aging.

  16. VizieR Online Data Catalog: Clusters of galaxies in SDSS-III (Wen+, 2012)

    Wen, Z. L.; Han, J. L.; Liu, F. S.

    2012-06-01

    Wen et al. (2009, Cat. J/ApJS/183/197) identified 39668 galaxy clusters from the SDSS DR6 by the discrimination of member galaxies of clusters using photometric redshifts of galaxies. Wen & Han (2011ApJ...734...68W) improved the method and successfully identified the high-redshift clusters from the deep fields of the Canada-France-Hawaii Telescope (CFHT) Wide survey, the CHFT Deep survey, the Cosmic Evolution Survey, and the Spitzer Wide-area InfraRed Extragalactic survey. Here, we follow and improve the algorithm to identify clusters from SDSS-III (SDSS Data Release 8; Aihara et al. 2011ApJS..193...29A, see Cat. II/306). (1 data file).

  17. Stellar Kinematics and Structural Properties of Virgo Cluster Dwarf Early-Type Galaxies from the SMAKCED Project

    Toloba, Elisa; Guhathakurta, Puragra; Peletier, Reynier; Boselli, Alessandro; Lisker, Thorsten; Emsellem, Eric; Simon, Joshua D.; van de Ven, Glenn; Smakced Collaboration, [Unknown

    2015-01-01

    We analyze the stellar kinematics of 39 dwarf early-type galaxies (dEs) in the Virgo cluster. This is the largest survey conducted so far on spatially resolved kinematics of dEs. This sample is representative of the early-type population in the absolute magnitude range -19.0

  18. The ATLAS3D project - X. On the origin of the molecular and ionized gas in early-type galaxies

    Davis, Timothy A.; Alatalo, Katherine; Sarzi, Marc; Bureau, Martin; Young, Lisa M.; Blitz, Leo; Serra, Paolo; Crocker, Alison F.; Krajnović, Davor; McDermid, Richard M.; Bois, Maxime; Bournaud, Frédéric; Cappellari, Michele; Davies, Roger L.; Duc, Pierre-Alain; de Zeeuw, P. Tim; Emsellem, Eric; Khochfar, Sadegh; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Scott, Nicholas; Weijmans, Anne-Marie

    2011-01-01

    We make use of interferometric CO and H I observations, and optical integral-field spectroscopy from the ATLAS3D survey, to probe the origin of the molecular and ionized interstellar medium (ISM) in local early-type galaxies. We find that 36 ± 5 per cent of our sample of fast-rotating early-type

  19. The ATLAS3D project : X. On the origin of the molecular and ionized gas in early-type galaxies

    Davis, Timothy A.; Alatalo, Katherine; Sarzi, Marc; Bureau, Martin; Young, Lisa M.; Blitz, Leo; Serra, Paolo; Crocker, Alison F.; Krajnovic, Davor; McDermid, Richard M.; Bois, Maxime; Bournaud, Frederic; Cappellari, Michele; Davies, Roger L.; Duc, Pierre-Alain; de Zeeuw, P. Tim; Emsellem, Eric; Khochfar, Sadegh; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Scott, Nicholas; Weijmans, Anne-Marie

    2011-01-01

    We make use of interferometric CO and H i observations, and optical integral-field spectroscopy from the ATLAS3D survey, to probe the origin of the molecular and ionized interstellar medium (ISM) in local early-type galaxies. We find that 36 +/- 5 per cent of our sample of fast-rotating early-type

  20. Timing the formation and assembly of early-type galaxies via spatially resolved stellar populations analysis

    Martín-Navarro, Ignacio; Vazdekis, Alexandre; Falcón-Barroso, Jesús; La Barbera, Francesco; Yıldırım, Akın; van de Ven, Glenn

    2018-04-01

    To investigate star formation and assembly processes of massive galaxies, we present here a spatially resolved stellar population analysis of a sample of 45 elliptical galaxies (Es) selected from the Calar Alto Legacy Integral Field Area survey. We find rather flat age and [Mg/Fe] radial gradients, weakly dependent on the effective velocity dispersion of the galaxy within half-light radius. However, our analysis shows that metallicity gradients become steeper with increasing galaxy velocity dispersion. In addition, we have homogeneously compared the stellar population gradients of our sample of Es to a sample of nearby relic galaxies, i.e. local remnants of the high-z population of red nuggets. This comparison indicates that, first, the cores of present-day massive galaxies were likely formed in gas-rich, rapid star formation events at high redshift (z ≳ 2). This led to radial metallicity variations steeper than observed in the local Universe, and positive [Mg/Fe] gradients. Secondly, our analysis also suggests that a later sequence of minor dry mergers, populating the outskirts of early-type galaxies (ETGs), flattened the pristine [Mg/Fe] and metallicity gradients. Finally, we find a tight age-[Mg/Fe] relation, supporting that the duration of the star formation is the main driver of the [Mg/Fe] enhancement in massive ETGs. However, the star formation time-scale alone is not able to fully explain our [Mg/Fe] measurements. Interestingly, our results match the expected effect that a variable stellar initial mass function would have on the [Mg/Fe] ratio.

  1. The SLUGGS survey: wide-field stellar kinematics of early-type galaxies

    Arnold, Jacob A. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Romanowsky, Aaron J.; Brodie, Jean P.; Woodley, Kristin A. [University of California Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States); Forbes, Duncan A.; Blom, Christina; Kartha, Sreeja S.; Pastorello, Nicola; Pota, Vincenzo; Usher, Christopher [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Strader, Jay [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Spitler, Lee R. [Department of Physics and Astronomy, Faculty of Sciences, Macquarie University, Sydney, NSW 2109 (Australia); Foster, Caroline, E-mail: romanow@ucolick.org [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW (Australia)

    2014-08-20

    We present stellar kinematics of 22 nearby early-type galaxies (ETGs), based on two-dimensional (2D) absorption line stellar spectroscopy out to ∼2-4 R {sub e} (effective radii), as part of the ongoing SLUGGS Survey. The galaxies span a factor of 20 in intrinsic luminosity, as well as a full range of environment and ETG morphology. Our data consist of good velocity resolution (σ{sub inst} ∼ 25 km s{sup –1}) integrated stellar-light spectra extracted from the individual slitlets of custom made Keck/DEIMOS slitmasks. We extract stellar kinematics measurements (V, σ, h {sub 3}, and h {sub 4}) for each galaxy. Combining with literature values from smaller radii, we present 2D spatially resolved maps of the large-scale kinematic structure in each galaxy. We find that the kinematic homogeneity found inside 1 R {sub e} often breaks down at larger radii, where a variety of kinematic behaviors are observed. While central slow rotators remain slowly rotating in their halos, central fast rotators show more diversity, ranging from rapidly increasing to rapidly declining specific angular momentum profiles in the outer regions. There are indications that the outer trends depend on morphological type, raising questions about the proposed unification of the elliptical and lenticular (S0) galaxy families in the ATLAS{sup 3D} survey. Several galaxies in our sample show multiple lines of evidence for distinct disk components embedded in more slowly rotating spheroids, and we suggest a joint photometric-kinematic approach for robust bulge-disk decomposition. Our observational results appear generally consistent with a picture of two-phase (in-situ plus accretion) galaxy formation.

  2. The Total Mass of the Early-Type Galaxy NGC 4649 (M60

    Ćirković, M. M.

    2008-12-01

    Full Text Available In this paper the problem of the total mass and the total mass-to-light ratio of the early-type galaxy NGC~4649 (M60 is analyzed. Use is made of two independent techniques: the X-ray methodology which is based on the temperature of the X-ray halo of NGC~4649 and the tracer mass estimator (TME which uses globular clusters (GCs observed in this galaxy. The mass is calculated in Newtonian and MOdified Newtonian Dynamics (MOND approaches and it is found that inside 3 effective radii ($R_e$ there is no need for large amounts of dark matter. Beyond $3R_e$ the dark matter starts to play important dynamical role. The possible reasons for the discrepancy between the estimates of the total mass based on X-rays and TME in the outer regions of NGC~4649 are also discussed.

  3. Abundance patterns in the interstellar medium of early-type galaxies observed with Suzaku

    Konami, Saori; Matsushita, Kyoko; Tamagawa, Toru; Nagino, Ryo

    2014-01-01

    We have analyzed 17 early-type galaxies, 13 ellipticals and 4 S0 galaxies, observed with Suzaku, and investigated metal abundances (O, Mg, Si, and Fe) and abundance ratios (O/Fe, Mg/Fe, and Si/Fe) in the interstellar medium (ISM). The emission from each on-source region, which is four times the effective radius, r e , is reproduced with one-temperature (1T) or two-temperature (2T) thermal plasma models as well as a multi-temperature model, using APEC plasma code version 2.0.1. The multi-temperature model gave almost the same abundances and abundance ratios with the 1T or 2T models. The weighted averages of the O, Mg, Si, and Fe abundances of all the sample galaxies derived from the multi-temperature model fits are 0.83 ± 0.04, 0.93 ± 0.03, 0.80 ± 0.02, and 0.80 ± 0.02 solar, respectively, in solar units according to the solar abundance table by Lodders in 2003. These abundances show no significant dependence on the morphology and environment. The systematic differences in the derived metal abundances between versions 2.0.1 and 1.3.1 of the APEC plasma codes were investigated. The derived O and Mg abundances in the ISM agree with the stellar metallicity within an aperture with a radius of one r e derived from optical spectroscopy. From these results, we discuss the past and present Type Ia supernova rates and star formation histories in early-type galaxies.

  4. Gas-rich dwarfs and accretion phenomena in early-type galaxies

    Silk, J.; Norman, C.

    1979-01-01

    An analysis is presented of the combined effects of cloud accretion and galactic winds and coronae. An accretion model is developed wherein gas-rich dwarf galaxies are accreted into galactic halos, which provides an adequate source of H I to account for observations of neutral gas in early-type galaxies. Accretion is found to fuel the wind, thereby regulating the accretion flow and yielding a time-dependent model for star formation, enrichment, and nuclear activity. The permissible parameter range for intergalactic gas clouds and galaxy groups is discussed, along with the frequency of gas-rich dwarfs and their large ratios of gas mass to luminosity. Also considered is the occurrence of gas stripping and the consequent formation of dwarf spheroidal systems that remain in the halo, and gas clouds that dissipate and suffer further infall. A cosmological implication of the model is that, because the characteristic time scale of a gas-rich dwarf galaxy to be accreted and lose its gas is comparable to a Hubble time, there may have been a far more extensive primordial distribution of such systems at earlier epochs.

  5. UNDERSTANDING THE STRUCTURE OF THE HOT INTERSTELLAR MEDIUM IN NORMAL EARLY-TYPE GALAXIES.

    Traynor, Liam; Kim, Dong-Woo; Chandra Galaxy Atlas

    2018-01-01

    The hot interstellar medium (ISM) of early-type galaxies (ETG's) provides crucial insight into the understanding of their formation and evolution. Mechanisms such as type Ia supernovae heating, AGN feedback, deepening potential depth through dark matter assembly and ramp-pressure stripping are known to affect the structure of the ISM. By using temperature maps and radial temperature profiles of the hot ISM from ~70 ETG's with archival Chandra data, it is possible to classify the galaxy's ISM into common structural types. This is extended by using 3D fitting of the radial temperature profile in order to provide models that further constrain the structural types. Five structural types are present, negative (temperature decreases with radii), positive (temperature increases with radii), hybrid-dip (temperature decreases at small radii and increases at large radii), hybrid-bump (inverse of hybrid-dip) and quasi-isothermal (temperature is constant at all radii). This work will be continued by 1) determining which mechanisms are present in which galaxies and 2) analysing the model parameters between galaxies within each structural type to determine whether each type can be described by a single set of model parameters, indicating that the same physical processes are responsible for creating that structural type.

  6. OXYGEN METALLICITY DETERMINATIONS FROM OPTICAL EMISSION LINES IN EARLY-TYPE GALAXIES

    Athey, Alex E.; Bregman, Joel N.

    2009-01-01

    We measured the oxygen abundances of the warm (T ∼ 10 4 K) phase of gas in seven early-type galaxies through long-slit observations. A template spectra was constructed from galaxies void of warm gas and subtracted from the emission-line galaxies, allowing for a clean measurement of the nebular lines. The ratios of the emission lines are consistent with photoionization, which likely originates from the ultraviolet flux of postasymototic giant branch stars. We employ H II region photoionization models to determine a mean oxygen metallicity of 1.01 ± 0.50 solar for the warm interstellar medium (ISM) in this sample. This warm ISM 0.5-1.5 solar metallicity is consistent with modern determinations of the metallicity in the hot (T ∼ 10 6 -10 7 K) ISM and the upper range of this warm ISM metallicity is consistent with stellar population metallicity determinations. A solar metallicity of the warm ISM favors an internal origin for the warm ISM such as asymptotic giant branch mass loss within the galaxy.

  7. The HST/ACS Coma Cluster Survey : VI. Colour gradients in giant and dwarf early-type galaxies

    den Brok, M.; Peletier, R. F.; Valentijn, E. A.; Balcells, Marc; Carter, D.; Erwin, P.; Ferguson, H. C.; Goudfrooij, P.; Graham, A. W.; Hammer, D.; Lucey, J. R.; Trentham, N.; Guzman, R.; Hoyos, C.; Kleijn, G. Verdoes; Jogee, S.; Karick, A. M.; Marinova, I.; Mouhcine, M.; Weinzirl, T.

    Using deep, high-spatial-resolution imaging from the Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) Coma Cluster Treasury Survey, we determine colour profiles of early-type galaxies in the Coma cluster. From 176 galaxies brighter than M-F814W(AB) = -15 mag that are either

  8. Early-type galaxies in the Antlia cluster: catalogue and isophotal analysis

    Calderón, Juan P.; Bassino, Lilia P.; Cellone, Sergio A.; Gómez, Matías

    2018-06-01

    We present a statistical isophotal analysis of 138 early-type galaxies in the Antlia cluster, located at a distance of ˜ 35 Mpc. The observational material consists of CCD images of four 36 × 36 arcmin2 fields obtained with the MOSAIC II camera at the Blanco 4-m telescope at Cerro Tololo Interamerican Observatory. Our present work supersedes previous Antlia studies in the sense that the covered area is four times larger, the limiting magnitude is MB ˜ -9.6 mag, and the surface photometry parameters of each galaxy are derived from Sérsic model fits extrapolated to infinity. In a companion previous study we focused on the scaling relations obtained by means of surface photometry, and now we present the data, on which the previous paper is based, the parameters of the isophotal fits as well as an isophotal analysis. For each galaxy, we derive isophotal shape parameters along the semimajor axis and search for correlations within different radial bins. Through extensive statistical tests, we also analyse the behaviour of these values against photometric and global parameters of the galaxies themselves. While some galaxies do display radial gradients in their ellipticity (ɛ) and/or their Fourier coefficients, differences in mean values between adjacent regions are not statistically significant. Regarding Fourier coefficients, dwarf galaxies usually display gradients between all adjacent regions, while non-dwarfs tend to show this behaviour just between the two outermost regions. Globally, there is no obvious correlation between Fourier coefficients and luminosity for the whole magnitude range (-12 ≳ MV ≳ -22); however, dwarfs display much higher dispersions at all radii.

  9. Early-type galaxies in the Antlia Cluster: Catalogue and isophotal analysis

    Calderón, Juan P.; Bassino, Lilia P.; Cellone, Sergio A.; Gómez, Matías

    2018-03-01

    We present a statistical isophotal analysis of 138 early-type galaxies in the Antlia cluster, located at a distance of ˜ 35 Mpc. The observational material consists of CCD images of four 36 arcmin × 36 arcmin fields obtained with the MOSAIC II camera at the Blanco 4-m telescope at CTIO. Our present work supersedes previous Antlia studies in the sense that the covered area is four times larger, the limiting magnitude is MB ˜ -9.6 mag, and the surface photometry parameters of each galaxy are derived from Sérsic model fits extrapolated to infinity. In a companion previous study we focused on the scaling relations obtained by means of surface photometry, and now we present the data, on which the previous paper is based, the parameters of the isophotal fits as well as an isophotal analysis. For each galaxy, we derive isophotal shape parameters along the semi-major axis and search for correlations within different radial bins. Through extensive statistical tests, we also analyse the behaviour of these values against photometric and global parameters of the galaxies themselves. While some galaxies do display radial gradients in their ellipticity (ɛ) and/or their Fourier coefficients, differences in mean values between adjacent regions are not statistically significant. Regarding Fourier coefficients, dwarf galaxies usually display gradients between all adjacent regions, while non-dwarfs tend to show this behaviour just between the two outermost regions. Globally, there is no obvious correlation between Fourier coefficients and luminosity for the whole magnitude range (-12 ≳ MV ≳ -22); however, dwarfs display much higher dispersions at all radii.

  10. EARLY-TYPE GALAXIES WITH TIDAL DEBRIS AND THEIR SCALING RELATIONS IN THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S4G)

    Kim, Taehyun; Sheth, Kartik; Muñoz-Mateos, Juan-Carlos; Hinz, Joannah L.; Zaritsky, Dennis; Lee, Myung Gyoon; Gadotti, Dimitri A.; Knapen, Johan H.; Schinnerer, Eva; Ho, Luis C.; Madore, Barry F.; Laurikainen, Eija; Salo, Heikki; Athanassoula, E.; Bosma, Albert; De Swardt, Bonita; Comerón, Sébastien; Regan, Michael W.; Menéndez-Delmestre, Karín; De Paz, Armando Gil

    2012-01-01

    Tidal debris around galaxies can yield important clues on their evolution. We have identified tidal debris in 11 early-type galaxies (T ≤ 0) from a sample of 65 early types drawn from the Spitzer Survey of Stellar Structure in Galaxies (S 4 G). The tidal debris includes features such as shells, ripples, and tidal tails. A variety of techniques, including two-dimensional decomposition of galactic structures, were used to quantify the residual tidal features. The tidal debris contributes ∼3%-10% to the total 3.6 μm luminosity of the host galaxy. Structural parameters of the galaxies were estimated using two-dimensional profile fitting. We investigate the locations of galaxies with tidal debris in the fundamental plane and Kormendy relation. We find that galaxies with tidal debris lie within the scatter of early-type galaxies without tidal features. Assuming that the tidal debris is indicative of recent gravitational interaction or merger, this suggests that these galaxies have either undergone minor merging events so that the overall structural properties of the galaxies are not significantly altered, or they have undergone a major merging events but already have experienced sufficient relaxation and phase mixing so that their structural properties become similar to those of the non-interacting early-type galaxies.

  11. SPITZER OBSERVATIONS OF PASSIVE AND STAR-FORMING EARLY-TYPE GALAXIES: AN INFRARED COLOR-COLOR SEQUENCE

    Temi, Pasquale; Brighenti, Fabrizio; Mathews, William G.

    2009-01-01

    We describe the infrared properties of a large sample of early-type galaxies, comparing data from the Spitzer archive with Ks-band emission from the Two Micron All Sky Survey. While most representations of this data result in correlations with large scatter, we find a remarkably tight relation among colors formed by ratios of luminosities in Spitzer-Multiband Imaging Photometer bands (24, 70, and 160 μm) and the Ks band. Remarkably, this correlation among E and S0 galaxies follows that of nearby normal galaxies of all morphological types. In particular, the tight infrared color-color correlation for S0 galaxies alone follows that of the entire Hubble sequence of normal galaxies, roughly in order of galaxy type from ellipticals to spirals to irregulars. The specific star formation rate (SFR) of S0 galaxies estimated from the 24 μm luminosity increases with decreasing K-band luminosity (or stellar mass) from essentially zero, as with most massive ellipticals, to rates typical of irregular galaxies. Moreover, the luminosities of the many infrared-luminous S0 galaxies can significantly exceed those of the most luminous (presumably post-merger) E galaxies. SFRs in the most infrared-luminous S0 galaxies approach 1-10 solar masses per year. Consistently, with this picture we find that while most early-type galaxies populate an infrared red sequence, about 24% of the objects (mostly S0s) are in an infrared blue cloud together with late-type galaxies. For those early-type galaxies also observed at radio frequencies, we find that the far-infrared luminosities correlate with the mass of neutral and molecular hydrogen, but the scatter is large. This scatter suggests that the star formation may be intermittent or that similar S0 galaxies with cold gaseous disks of nearly equal mass can have varying radial column density distributions that alter the local and global SFRs.

  12. Evidence for a constant IMF in early-type galaxies based on their X-ray binary populations

    Peacock, Mark B.; Zepf, Stephen E.; Maccarone, Thomas J.; Kundu, Arunav; Gonzalez, Anthony H.; Lehmer, Bret D.; Maraston, Claudia

    2014-01-01

    A number of recent studies have proposed that the stellar initial mass function (IMF) of early type galaxies varies systematically as a function of galaxy mass, with higher mass galaxies having bottom heavy IMFs. These bottom heavy IMFs have more low-mass stars relative to the number of high mass stars, and therefore naturally result in proportionally fewer neutron stars and black holes. In this paper, we specifically predict the variation in the number of black holes and neutron stars based ...

  13. A Comparison of Galaxy Bulge+Disk Decomposition Between Pan-STARRS and SDSS

    Lokken, Martine Elena; McPartland, Conor; Sanders, David B.

    2018-01-01

    Measurements of the size and shape of bulges in galaxies provide key constraints for models of galaxy evolution. A comprehensive catalog of bulge measurements for Sloan Digital Sky Survey (SDSS) DR7 galaxies is currently available to the public. However, the Pan-STARRS1 (PS1) 3π survey now covers the same region with ~1-2 mag deeper photometry, a ~10-30% smaller PSF, and additional coverage in y-band. To test how much improvement in galaxy parameter measurements (e.g. bulge + disk) can be achieved using the new PS1 data, we make use of ultra-deep imaging data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP). We fit bulge+disk models to images of 372 bright (mi SSP images shows a tighter correlation between PS1 and SSP measurements for both bulge and disk parameters. Bulge parameters, such as bulge-to-total fraction and bulge radius, show the strongest improvement. However, measurements of all parameters degrade for galaxies with total r-band magnitude below the SDSS spectroscopic limit, mr = 17.7. We plan to use the PS1 3π survey data to produce an updated catalog of bulge+disk decomposition measurements for the entire SDSS DR7 spectroscopic galaxy sample.

  14. The diversity of atomic hydrogen in slow rotator early-type galaxies

    Young, Lisa M.; Serra, Paolo; Krajnović, Davor; Duc, Pierre-Alain

    2018-06-01

    We present interferometric observations of H I in nine slow rotator early-type galaxies of the Atlas3D sample. With these data, we now have sensitive H I searches in 34 of the 36 slow rotators. The aggregate detection rate is 32 per cent ± 8 per cent, consistent with the previous work; however, we find two detections with extremely high H I masses, whose gas kinematics are substantially different from what was previously known about H I in slow rotators. These two cases (NGC 1222 and NGC 4191) broaden the known diversity of H I properties in slow rotators. NGC 1222 is a merger remnant with prolate-like rotation and, if it is indeed prolate in shape, an equatorial gas disc; NGC 4191 has two counter-rotating stellar discs and an unusually large H I disc. We comment on the implications of this disc for the formation of 2σ galaxies. In general, the H I detection rate, the incidence of relaxed H I discs, and the H I/stellar mass ratios of slow rotators are indistinguishable from those of fast rotators. These broad similarities suggest that the H I we are detecting now is unrelated to the galaxies' formation processes and was often acquired after their stars were mostly in place. We also discuss the H I non-detections; some of these galaxies that are undetected in H I or CO are detected in other tracers (e.g. FIR fine structure lines and dust). The question of whether there is cold gas in massive galaxies' scoured nuclear cores still needs work. Finally, we discuss an unusual isolated H I cloud with a surprisingly faint (undetected) optical counterpart.

  15. The Diversity of Atomic Hydrogen in Slow Rotator Early-type Galaxies

    Young, Lisa M.; Serra, Paolo; Krajnović, Davor; Duc, Pierre-Alain

    2018-02-01

    We present interferometric observations of H I in nine slow rotator early-type galaxies of the ATLAS3D sample. With these data, we now have sensitive H I searches in 34 of the 36 slow rotators. The aggregate detection rate is 32% ± 8%, consistent with previous work; however, we find two detections with extremely high H I masses, whose gas kinematics are substantially different from what was previously known about H I in slow rotators. These two cases (NGC 1222 and NGC 4191) broaden the known diversity of H I properties in slow rotators. NGC 1222 is a merger remnant with prolate-like rotation and, if it is indeed prolate in shape, an equatorial gas disc; NGC 4191 has two counterrotating stellar discs and an unusually large H I disc. We comment on the implications of this disc for the formation of 2σ galaxies. In general, the H I detection rate, the incidence of relaxed H I discs, and the H I/stellar mass ratios of slow rotators are indistinguishable from those of fast rotators. These broad similarities suggest that the H I we are detecting now is unrelated to the galaxies' formation processes and was often acquired after their stars were mostly in place. We also discuss the H I nondetections; some of these galaxies that are undetected in H I or CO are detected in other tracers (e.g. FIR fine structure lines and dust). The question of whether there is cold gas in massive galaxies' scoured nuclear cores still needs work. Finally, we discuss an unusual isolated H I cloud with a surprisingly faint (undetected) optical counterpart.

  16. COSMIC EVOLUTION OF SIZE AND VELOCITY DISPERSION FOR EARLY-TYPE GALAXIES

    Fan, L.; Lapi, A.; Bressan, A.; De Zotti, G.; Danese, L.; Bernardi, M.

    2010-01-01

    Massive (stellar mass M * ∼> 3 x 10 10 M sun ), passively evolving galaxies at redshifts z ∼> 1 exhibit on average physical sizes smaller, by factors ∼3, than local early-type galaxies (ETGs) endowed with the same stellar mass. Small sizes are in fact expected on theoretical grounds, if dissipative collapse occurs. Recent results show that the size evolution at z ∼ 1, where both compact and already extended galaxies are observed and the scatter in size is remarkably larger than it is locally. The presence at high redshift of a significant number of ETGs with the same size as their local counterparts, as well as ETGs with quite small size (∼ H (z). We demonstrate that the projected mass of compact, high-redshift galaxies and that of local ETGs within the same physical radius, the nominal half-luminosity radius of high-redshift ETGs, differ substantially in that the high-redshift ETGs are on average significantly denser. This result suggests that the physical mechanism responsible for the size increase should also remove mass from central galaxy regions (r ∼ 1, we predict the local velocity dispersion distribution function. On comparing it to the observed one, we show that velocity dispersion evolution of massive ETGs is fully compatible with the observed average evolution in size at constant stellar mass. Less massive ETGs (with stellar masses M * ∼ 10 M sun ) are expected to evolve less both in size and in velocity dispersion, because their evolution is essentially determined by supernova feedback, which cannot yield winds as powerful as those triggered by quasars. The differential evolution is expected to leave imprints in the size versus luminosity/mass, velocity dispersion versus luminosity/mass, and central black hole mass versus velocity dispersion relationships, as observed in local ETGs.

  17. Differential population synthesis of early-type galaxies. III. Synthesis results

    Pickles, A.J.

    1985-01-01

    Synthesis results are presented for 12 elliptical and five lenticular galaxies which cover nearly a 6 mag range of absolute magnitude in the Fornax cluster (V = 1430 km s -1 ). The results of age, metallicity, and mass-to-light ratio (M/L) determinations are presented differentially as functions of galactic luminosity and morphology. Bright elliptical galaxies are well represented by main-sequence turnoff colors of (V-R)/sub c/roughly-equal0.37 and B-Vroughly-equal0.70, in good agreement with O'Connell's results for bright Virgo ellipticals. The relatively young main-sequence turnoff ages, of 6-10 Gyr for ellipticals of all luminosities, indicate that substantial star formation activity occurred in these galaxies for a period of 6dagger10 Gyr after the epoch of globular cluster formation. There is strong evidence for small amounts of current star formation in at least the brightest ellipticals of all luminosities, indicate that substantial star formation in at least the brightest ellipticals, variation in the amount of which may account for significant dispersion in the cluster U-V versus V color-magnitude relation. A metallicity gradient in [Fe/H] of at least 0.16 dex per absolute magnitude is derived, with the brightest ellipticals being 2 to 3 times more metal-rich than solar. The mean metallicities and turnoff ages of the faintest ellipticals are probably dependent on environment. Distance-independent upper limits to galaxy M/L ratios derived from the syntheses conform well with M/L ratios derived from velocity dispersion measurements and give no evidence for unseen mass in the nuclei of early type galaxies of any luminosity

  18. The progenitors of the compact early-type galaxies at high redshift

    Williams, Christina C.; Giavalisco, Mauro; Lee, Bomee; Cassata, Paolo; Tundo, Elena; Conselice, Christopher J.; Wiklind, Tommy; Guo, Yicheng; Barro, Guillermo; Faber, Sandra M.; Koo, David C.; Wuyts, Stijn; Bell, Eric F.; Dekel, Avishai; Ferguson, Henry C.; Grogin, Norman; Koekemoer, Anton; Hathi, Nimish; Huang, Kuang-Han; Kocevski, Dale

    2014-01-01

    We use GOODS and CANDELS images to identify progenitors of massive (M > 10 10 M ☉ ) compact early-type galaxies (ETGs) at z ∼ 1.6. Because merging and accretion increase the size of the stellar component of galaxies, if the progenitors are among known star-forming galaxies, these must be compact themselves. We select candidate progenitors among compact Lyman-break galaxies at z ∼ 3 on the basis of their mass, star-formation rate (SFR), and central stellar density, and we find that these account for a large fraction of, and possibly all, compact ETGs at z ∼ 1.6. We find that the average far-UV spectral energy distribution (SED) of the candidates is redder than that of the non-candidates, but the optical and mid-IR SED are the same, implying that the redder UV of the candidates is inconsistent with larger dust obscuration and consistent with more evolved (aging) star formation. This is in line with other evidence suggesting that compactness is a sensitive predictor of passivity among high-redshift massive galaxies. We also find that the light distribution of both the compact ETGs and their candidate progenitors does not show any extended 'halos' surrounding the compact 'core,' both in individual images and in stacks. We argue that this is generally inconsistent with the morphology of merger remnants, even if gas rich, as predicted by N-body simulations. This suggests that the compact ETGs formed via highly dissipative, mostly gaseous accretion of units whose stellar components are very small and undetected in the Hubble Space Telescope images, with their stellar mass assembling in situ, and that they have not experienced any major merging until the epoch of observations at z ∼ 1.6.

  19. The progenitors of the compact early-type galaxies at high redshift

    Williams, Christina C.; Giavalisco, Mauro; Lee, Bomee [Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Cassata, Paolo [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Tundo, Elena; Conselice, Christopher J. [The School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Wiklind, Tommy [Joint ALMA Observatory, ESO, Santiago (Chile); Guo, Yicheng; Barro, Guillermo; Faber, Sandra M.; Koo, David C. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Wuyts, Stijn [Max-Planck-Institut für Extraterrestrische Physik (MPE), Postfach 1312, D-85741 Garching (Germany); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Dekel, Avishai [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Ferguson, Henry C.; Grogin, Norman; Koekemoer, Anton [Space Telescope Science Institute, 3700 San Martin Boulevard, Baltimore, MD 21218 (United States); Hathi, Nimish [Carnegie Observatories, Pasadena, CA 91101 (United States); Huang, Kuang-Han [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Kocevski, Dale, E-mail: ccwillia@astro.umass.edu [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); and others

    2014-01-01

    We use GOODS and CANDELS images to identify progenitors of massive (M > 10{sup 10} M {sub ☉}) compact early-type galaxies (ETGs) at z ∼ 1.6. Because merging and accretion increase the size of the stellar component of galaxies, if the progenitors are among known star-forming galaxies, these must be compact themselves. We select candidate progenitors among compact Lyman-break galaxies at z ∼ 3 on the basis of their mass, star-formation rate (SFR), and central stellar density, and we find that these account for a large fraction of, and possibly all, compact ETGs at z ∼ 1.6. We find that the average far-UV spectral energy distribution (SED) of the candidates is redder than that of the non-candidates, but the optical and mid-IR SED are the same, implying that the redder UV of the candidates is inconsistent with larger dust obscuration and consistent with more evolved (aging) star formation. This is in line with other evidence suggesting that compactness is a sensitive predictor of passivity among high-redshift massive galaxies. We also find that the light distribution of both the compact ETGs and their candidate progenitors does not show any extended 'halos' surrounding the compact 'core,' both in individual images and in stacks. We argue that this is generally inconsistent with the morphology of merger remnants, even if gas rich, as predicted by N-body simulations. This suggests that the compact ETGs formed via highly dissipative, mostly gaseous accretion of units whose stellar components are very small and undetected in the Hubble Space Telescope images, with their stellar mass assembling in situ, and that they have not experienced any major merging until the epoch of observations at z ∼ 1.6.

  20. Wide-field kinematic structure of early-type galaxy halos

    Arnold, Jacob Antony

    2013-12-01

    The stellar halos of nearby galaxies bare the signatures of the mass-assembly processes that have driven galaxy evolution over the last ˜10 Gyr. Finding and interpreting these relict clues in galaxies within and beyond the local group offers one of the most promising avenues for understanding how galaxies accumulate their stars over time. To tackle this problem we have performed a systematic study of the wide-field kinematic structure of nearby (Dspectroscopy out to several effective radii (˜3 R e). The 22 galaxies presented here span a range of environments (field, group, and cluster), intrinsic luminosities (-22.4 infrared Calcium II triplet. For each spectrum, we parameterize the line-of-sight velocity distribution (LOSVD) as a truncated Gauss-Hermite series convolved with an optimally weighted combination of stellar templates. These kinematic measurements (V, sigma, h3, and h4) are combined with literature values to construct spatially resolved maps of large-scale kinematic structure. A variety of kinematic behaviors are observed beyond ~1 Re, potentially reflecting the stochastic and chaotic assembly of stellar bulges and halos in early-type galaxies. Next, we describe a global analysis (out to 5 Re) of kinematics and metallicity in the nearest S0 galaxy, NGC 3115, along with implications for its assembly history. The data include high-quality wide-field imaging and multi-slit spectra of the field stars and globular clusters (GCs). Within two effective radii, the bulge (as traced by the stars and metal-rich GCs) is flattened and rotates rapidly. At larger radii, the rotation declines dramatically, while the characteristic GC metallicities also decrease with radius. We argue that this pattern is not naturally explained by a binary major merger, but instead by a two-phase assembly process where the inner regions have formed in an early violent, dissipative phase, followed by the protracted growth of the outer parts via minor mergers. To test this hypothesis

  1. Early-type Galaxy Spin Evolution in the Horizon-AGN Simulation

    Choi, Hoseung; Yi, Sukyoung K.; Dubois, Yohan; Kimm, Taysun; Devriendt, Julien. E. G.; Pichon, Christophe

    2018-04-01

    Using the Horizon-AGN simulation data, we study the relative role of mergers and environmental effects in shaping the spin of early-type galaxies (ETGs) after z ≃ 1. We follow the spin evolution of 10,037 color-selected ETGs more massive than {10}10 {M}ȯ that are divided into four groups: cluster centrals (3%), cluster satellites (33%), group centrals (5%), and field ETGs (59%). We find a strong mass dependence of the slow rotator fraction, f SR, and the mean spin of massive ETGs. Although we do not find a clear environmental dependence of f SR, a weak trend is seen in the mean value of the spin parameter driven by the satellite ETGs as they gradually lose their spin as their environment becomes denser. Galaxy mergers appear to be the main cause of total spin changes in 94% of the central ETGs of halos with {M}vir}> {10}12.5 {M}ȯ , but only 22% of satellite and field ETGs. We find that non-merger-induced tidal perturbations better correlate with the galaxy spin down in satellite ETGs than in mergers. Given that the majority of ETGs are not central in dense environments, we conclude that non-merger tidal perturbation effects played a key role in the spin evolution of ETGs observed in the local (z < 1) universe.

  2. NOT DEAD YET: COOL CIRCUMGALACTIC GAS IN THE HALOS OF EARLY-TYPE GALAXIES

    Thom, Christopher; Tumlinson, Jason; Sembach, Kenneth R.; Werk, Jessica K.; Xavier Prochaska, J.; Oppenheimer, Benjamin D.; Peeples, Molly S.; Tripp, Todd M.; Katz, Neal S.; O'Meara, John M.; Ford, Amanda Brady; Davé, Romeel; Weinberg, David H.

    2012-01-01

    We report new observations of circumgalactic gas in the halos of early-type galaxies (ETGs) obtained by the COS-Halos Survey with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. We find that detections of H I surrounding ETGs are typically as common and strong as around star-forming galaxies, implying that the total mass of circumgalactic material is comparable in the two populations. For ETGs, the covering fraction for H I absorption above 10 16 cm –2 is ∼40%-50% within ∼150 kpc. Line widths and kinematics of the detected material show it to be cold (T ∼ 5 K) in comparison to the virial temperature of the host halos. The implied masses of cool, photoionized circumgalactic medium baryons may be up to 10 9 -10 11 M ☉ . Contrary to some theoretical expectations, strong halo H I absorbers do not disappear as part of the quenching of star formation. Even passive galaxies retain significant reservoirs of halo baryons that could replenish the interstellar gas reservoir and eventually form stars. This halo gas may feed the diffuse and molecular gas that is frequently observed inside ETGs.

  3. MORPHOLOGICAL QUENCHING OF STAR FORMATION: MAKING EARLY-TYPE GALAXIES RED

    Martig, Marie; Bournaud, Frederic; Teyssier, Romain; Dekel, Avishai

    2009-01-01

    We point out a natural mechanism for quenching of star formation in early-type galaxies (ETGs). It automatically links the color of a galaxy with its morphology and does not require gas consumption, removal or termination of gas supply. Given that star formation takes place in gravitationally unstable gas disks, it can be quenched when a disk becomes stable against fragmentation to bound clumps. This can result from the growth of a stellar spheroid, for instance by mergers. We present the concept of morphological quenching (MQ) using standard disk instability analysis, and demonstrate its natural occurrence in a cosmological simulation using an efficient zoom-in technique. We show that the transition from a stellar disk to a spheroid can be sufficient to stabilize the gas disk, quench star formation, and turn an ETG red and dead while gas accretion continues. The turbulence necessary for disk stability can be stirred up by sheared perturbations within the disk in the absence of bound star-forming clumps. While other quenching mechanisms, such as gas stripping, active galactic nucleus feedback, virial shock heating, and gravitational heating are limited to massive halos, MQ can explain the appearance of red ETGs also in halos less massive than ∼10 12 M sun . The dense gas disks observed in some of today's red ellipticals may be the relics of this mechanism, whereas red galaxies with quenched gas disks could be more frequent at high redshift.

  4. The hELENa project - II. Abundance distribution trends of early-type galaxies: from dwarfs to giants

    Sybilska, A.; Kuntschner, H.; van de Ven, G.; Vazdekis, A.; Falcón-Barroso, J.; Peletier, R. F.; Lisker, T.

    2018-06-01

    In this second paper of The role of Environment in shaping Low-mass Early-type Nearby galaxies (hELENa) series we study [Mg/Fe] abundance distribution trends of early-type galaxies (ETGs) observed with the Spectrographic Areal Unit for Research on Optical Nebulae integral field unit, spanning a wide range in mass and local environment densities: 20 low-mass early types (dEs) of Sybilska et al. and 258 massive early types (ETGs) of the ATLAS3D project, all homogeneously reduced and analysed. We show that the [Mg/Fe] ratios scale with velocity dispersion (σ) at fixed [Fe/H] and that they evolve with [Fe/H] along similar paths for all early types, grouped in bins of increasing local and global σ, as well as the second velocity moment Vrms, indicating a common inside-out formation pattern. We then place our dEs on the [Mg/Fe] versus [Fe/H] diagram of Local Group galaxies and show that dEs occupy the same region and show a similar trend line slope in the diagram as the high-metallicity stars of the Milky Way and the Large Magellanic Cloud. This finding extends the similar trend found for dwarf spheroidal versus dwarf irregular galaxies and supports the notion that dEs have evolved from late-type galaxies that have lost their gas at a point of their evolution, which likely coincided with them entering denser environments.

  5. THE SDSS-IV EXTENDED BARYON OSCILLATION SPECTROSCOPIC SURVEY: LUMINOUS RED GALAXY TARGET SELECTION

    Prakash, Abhishek; Licquia, Timothy C.; Newman, Jeffrey A.; Rao, Sandhya M. [PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Ross, Ashley J. [Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Dawson, Kyle S.; Bautista, Julian E.; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Kneib, Jean-Paul [Laboratoire d’Astrophysique, Ecole Polytechnique Fédérale de Lausanne Observatoire de Sauverny, 1290 Versoix (Switzerland); Percival, Will J. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Comparat, Johan [Instituto de Física Teórica, (UAM/CSIC), Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Tinker, Jeremy L. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Schlegel, David J. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States); Tojeiro, Rita [School of Physics and Astronomy, St Andrews, KY16 9SS (United Kingdom); Ho, Shirley; Lang, Dustin [Bruce and Astrid McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); McBride, Cameron K. [Harvard-Smithsonian Center for Astrophysics, Harvard University, 60 Garden Street, Cambridge, MA 02138 (United States); Zhu, Guangtun Ben, E-mail: abp15@pitt.edu [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); and others

    2016-06-01

    We describe the algorithm used to select the luminous red galaxy (LRG) sample for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV) using photometric data from both the SDSS and the Wide-field Infrared Survey Explorer . LRG targets are required to meet a set of color selection criteria and have z -band and i -band MODEL magnitudes z < 19.95 and 19.9 < i < 21.8, respectively. Our algorithm selects roughly 50 LRG targets per square degree, the great majority of which lie in the redshift range 0.6 < z < 1.0 (median redshift 0.71). We demonstrate that our methods are highly effective at eliminating stellar contamination and lower-redshift galaxies. We perform a number of tests using spectroscopic data from SDSS-III/BOSS ancillary programs to determine the redshift reliability of our target selection and its ability to meet the science requirements of eBOSS. The SDSS spectra are of high enough signal-to-noise ratio that at least ∼89% of the target sample yields secure redshift measurements. We also present tests of the uniformity and homogeneity of the sample, demonstrating that it should be clean enough for studies of the large-scale structure of the universe at higher redshifts than SDSS-III/BOSS LRGs reached.

  6. Alignments of galaxies within cosmic filaments from SDSS DR7

    Zhang, Youcai; Yang, Xiaohu; Wang, Huiyuan; Wang, Lei; Mo, H. J.; Van den Bosch, Frank C.

    2013-01-01

    Using a sample of galaxy groups selected from the Sloan Digital Sky Survey Data Release 7, we examine the alignment between the orientation of galaxies and their surrounding large-scale structure in the context of the cosmic web. The latter is quantified using the large-scale tidal field, reconstructed from the data using galaxy groups above a certain mass threshold. We find that the major axes of galaxies in filaments tend to be preferentially aligned with the directions of the filaments, while galaxies in sheets have their major axes preferentially aligned parallel to the plane of the sheets. The strength of this alignment signal is strongest for red, central galaxies, and in good agreement with that of dark matter halos in N-body simulations. This suggests that red, central galaxies are well aligned with their host halos, in quantitative agreement with previous studies based on the spatial distribution of satellite galaxies. There is a luminosity and mass dependence that brighter and more massive galaxies in filaments and sheets have stronger alignment signals. We also find that the orientation of galaxies is aligned with the eigenvector associated with the smallest eigenvalue of the tidal tensor. These observational results indicate that galaxy formation is affected by large-scale environments and strongly suggest that galaxies are aligned with each other over scales comparable to those of sheets and filaments in the cosmic web.

  7. Alignments of galaxies within cosmic filaments from SDSS DR7

    Zhang, Youcai; Yang, Xiaohu [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Nandan Road 80, Shanghai 200030 (China); Wang, Huiyuan [Key Laboratory for Research in Galaxies and Cosmology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang, Lei [Purple Mountain Observatory, the Partner Group of MPI für Astronomie, 2 West Beijing Road, Nanjing 210008 (China); Mo, H. J. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States); Van den Bosch, Frank C., E-mail: yczhang@shao.ac.cn, E-mail: xyang@sjtu.edu.cn [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)

    2013-12-20

    Using a sample of galaxy groups selected from the Sloan Digital Sky Survey Data Release 7, we examine the alignment between the orientation of galaxies and their surrounding large-scale structure in the context of the cosmic web. The latter is quantified using the large-scale tidal field, reconstructed from the data using galaxy groups above a certain mass threshold. We find that the major axes of galaxies in filaments tend to be preferentially aligned with the directions of the filaments, while galaxies in sheets have their major axes preferentially aligned parallel to the plane of the sheets. The strength of this alignment signal is strongest for red, central galaxies, and in good agreement with that of dark matter halos in N-body simulations. This suggests that red, central galaxies are well aligned with their host halos, in quantitative agreement with previous studies based on the spatial distribution of satellite galaxies. There is a luminosity and mass dependence that brighter and more massive galaxies in filaments and sheets have stronger alignment signals. We also find that the orientation of galaxies is aligned with the eigenvector associated with the smallest eigenvalue of the tidal tensor. These observational results indicate that galaxy formation is affected by large-scale environments and strongly suggest that galaxies are aligned with each other over scales comparable to those of sheets and filaments in the cosmic web.

  8. A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey

    Dilday, Benjamin; /Rutgers U., Piscataway /Chicago U. /KICP, Chicago; Bassett, Bruce; /Cape Town U., Dept. Math. /South African Astron. Observ.; Becker, Andrew; /Washington U., Seattle, Astron. Dept.; Bender, Ralf; /Munich, Tech. U. /Munich U. Observ.; Castander, Francisco; /Barcelona, IEEC; Cinabro, David; /Wayne State U.; Frieman, Joshua A.; /Chicago U. /Fermilab; Galbany, Lluis; /Barcelona, IFAE; Garnavich, Peter; /Notre Dame U.; Goobar, Ariel; /Stockholm U., OKC /Stockholm U.; Hopp, Ulrich; /Munich, Tech. U. /Munich U. Observ. /Tokyo U.

    2010-03-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z {le} 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 {le} z {le} 0.3. We find values for the cluster SN Ia rate of (0.37{sub -0.12-0.01}{sup +0.17+0.01}) SNur h{sup 2} and (0.55{sub -0.11-0.01}{sup +0.13+0.02}) SNur h{sup 2} (SNux = 10{sup -12}L{sub x{circle_dot}}{sup -1} yr{sup -1}) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31{sub -0.12-0.01}{sup +0.18+0.01}) SNur h{sup 2} and (0.49{sub -0.11-0.01}{sup +0.15+0.02}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04{sub -1.11-0.04}{sup +1.99+0.07}) SNur h{sup 2} and (0.36{sub -0.30-0.01}{sup +0.84+0.01}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94{sub -0.91-0.015}{sup +1.31+0.043} and 3.02{sub -1.03-0.048}{sup +1.31+0.062}, for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r{sub L} = [(0.49{sub -0.14}{sup +0.15}) + (0.91{sub -0.81}{sup +0.85}) x z] SNuB h{sup 2}. A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most 3 hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe that are

  9. A MEASUREMENT OF THE RATE OF TYPE Ia SUPERNOVAE IN GALAXY CLUSTERS FROM THE SDSS-II SUPERNOVA SURVEY

    Dilday, Benjamin; Jha, Saurabh W.; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Hopp, Ulrich; Castander, Francisco; Cinabro, David; Frieman, Joshua A.; Galbany, LluIs; Miquel, Ramon; Garnavich, Peter; Goobar, Ariel; Ihara, Yutaka; Kessler, Richard; Lampeitl, Hubert; Nichol, Robert C.; Marriner, John; Molla, Mercedes

    2010-01-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z ≤ 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 ≤ z ≤ 0.3. We find values for the cluster SN Ia rate of (0.37 +0.17+0.01 -0.12-0.01 ) SNur h 2 and (0.55 +0.13+0.02 -0.11-0.01 ) SNur h 2 (SNux = 10 -12 L -1 xsun yr -1 ) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31 +0.18+0.01 -0.12-0.01 ) SNur h 2 and (0.49 +0.15+0.02 -0.11-0.01 ) SNur h 2 in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04 +1.99+0.07 -1.11-0.04 ) SNur h 2 and (0.36 +0.84+0.01 -0.30-0.01 ) SNur h 2 in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94 +1.31+0.043 -0.91-0.015 and 3.02 +1.31+0.062 -1.03-0.048 , for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r L = [(0.49 +0.15 -0.14 )+(0.91 +0.85 -0.81 ) x z] SNuB h 2 . A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most three hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe that are hostless to be (9.4 +8.3 -5.1 )%.

  10. ABOUT THE LINEARITY OF THE COLOR-MAGNITUDE RELATION OF EARLY-TYPE GALAXIES IN THE VIRGO CLUSTER

    Smith Castelli, Analia V.; Faifer, Favio R. [Instituto de Astrofisica de La Plata (CCT-La Plata, CONICET-UNLP), Paseo del Bosque s/n, B1900FWA, La Plata (Argentina); Gonzalez, Nelida M. [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, La Plata, B1900FWA (Argentina); Forte, Juan Carlos, E-mail: asmith@fcaglp.unlp.edu.ar, E-mail: ngonzalez@fcaglp.unlp.edu.ar, E-mail: favio@fcaglp.unlp.edu.ar, E-mail: forte@fcaglp.unlp.edu.ar [CONICET-Planetario de la Ciudad de Buenos Aires ' ' Galileo Galilei' ' , Av. Sarmiento y B. Roldan, Ciudad Autonoma de Buenos Aires (Argentina)

    2013-07-20

    We revisit the color-magnitude relation of Virgo Cluster early-type galaxies in order to explore its alleged nonlinearity. To this aim, we reanalyze the relation already published from data obtained within the ACS Virgo Cluster Survey of the Hubble Space Telescope and perform our own photometry and analysis of the images of 100 early-type galaxies observed as part of this survey. In addition, we compare our results with those reported in the literature from data of the Sloan Digital Sky Survey. We have found that when the brightest galaxies and untypical systems are excluded from the sample, a linear relation arises in agreement with what is observed in other groups and clusters. The central regions of the brightest galaxies also follow this relation. In addition, we notice that Virgo contains at least four compact elliptical galaxies besides the well-known object VCC 1297 (NGC 4486B). Their locations in the ({mu}{sub eff})-luminosity diagram define a trend different from that followed by normal early-type dwarf galaxies, setting an upper limit in effective surface brightness and a lower limit in the effective radius for their luminosities. Based on the distribution of different galaxy sub-samples in the color-magnitude and ({mu}{sub eff})-luminosity diagrams, we draw some conclusions on their formation and the history of their evolution.

  11. ABOUT THE LINEARITY OF THE COLOR-MAGNITUDE RELATION OF EARLY-TYPE GALAXIES IN THE VIRGO CLUSTER

    Smith Castelli, Analía V.; Faifer, Favio R.; González, Nélida M.; Forte, Juan Carlos

    2013-01-01

    We revisit the color-magnitude relation of Virgo Cluster early-type galaxies in order to explore its alleged nonlinearity. To this aim, we reanalyze the relation already published from data obtained within the ACS Virgo Cluster Survey of the Hubble Space Telescope and perform our own photometry and analysis of the images of 100 early-type galaxies observed as part of this survey. In addition, we compare our results with those reported in the literature from data of the Sloan Digital Sky Survey. We have found that when the brightest galaxies and untypical systems are excluded from the sample, a linear relation arises in agreement with what is observed in other groups and clusters. The central regions of the brightest galaxies also follow this relation. In addition, we notice that Virgo contains at least four compact elliptical galaxies besides the well-known object VCC 1297 (NGC 4486B). Their locations in the (μ eff )-luminosity diagram define a trend different from that followed by normal early-type dwarf galaxies, setting an upper limit in effective surface brightness and a lower limit in the effective radius for their luminosities. Based on the distribution of different galaxy sub-samples in the color-magnitude and (μ eff )-luminosity diagrams, we draw some conclusions on their formation and the history of their evolution

  12. A near-infrared census of the multicomponent stellar structure of early-type dwarf galaxies in the Virgo cluster

    Janz, J.; Laurikainen, E.; Salo, H.; Lisker, T.; Hansson, K. S. A.; Meyer, H. T.; Paudel, S.; Peletier, R. F.; Den Brok, M.; Niemi, S.-M.; Toloba, E.; Hensler, G.; Falcón-Barroso, J.; Ryś, A.; Boselli, A.

    2014-01-01

    The fraction of star-forming to quiescent dwarf galaxies varies from almost infinity in the field to zero in the centers of rich galaxy clusters. What is causing this pronounced morphology-density relation? What do quiescent dwarf galaxies look like when studied in detail, and what conclusions can be drawn about their formation mechanism? Here we study a nearly magnitude-complete sample (–19 < M r < –16 mag) of 121 Virgo cluster early types with deep near-infrared images from the SMAKCED project. We fit two-dimensional models with optional inner and outer components, as well as bar and lens components (in ∼15% of the galaxies), to the galaxy images. While a single Sérsic function may approximate the overall galaxy structure, it does not entirely capture the light distribution of two-thirds of our galaxies, for which multicomponent models provide a better fit. This fraction of complex galaxies shows a strong dependence on luminosity, being larger for brighter objects. We analyze the global and component-specific photometric scaling relations of early-type dwarf galaxies and discuss similarities with bright early and late types. The dwarfs' global galaxy parameters show scaling relations that are similar to those of bright disk galaxies. The inner components are mostly fitted with Sérsic n values close to 1. At a given magnitude, they are systematically larger than the bulges of spirals, suggesting that they are not ordinary bulges. We argue that the multicomponent structures in early-type dwarfs are mostly a phenomenon inherent to the disks and may indeed stem from environmental processing.

  13. Dependence of the clustering properties of galaxies on stellar velocity dispersion in the Main galaxy sample of SDSS DR10

    Deng, Xin-Fa; Song, Jun; Chen, Yi-Qing; Jiang, Peng; Ding, Ying-Ping

    2014-08-01

    Using two volume-limited Main galaxy samples of the Sloan Digital Sky Survey Data Release 10 (SDSS DR10), we investigate the dependence of the clustering properties of galaxies on stellar velocity dispersion by cluster analysis. It is found that in the luminous volume-limited Main galaxy sample, except at r=1.2, richer and larger systems can be more easily formed in the large stellar velocity dispersion subsample, while in the faint volume-limited Main galaxy sample, at r≥0.9, an opposite trend is observed. According to statistical analyses of the multiplicity functions, we conclude in two volume-limited Main galaxy samples: small stellar velocity dispersion galaxies preferentially form isolated galaxies, close pairs and small group, while large stellar velocity dispersion galaxies preferentially inhabit the dense groups and clusters. However, we note the difference between two volume-limited Main galaxy samples: in the faint volume-limited Main galaxy sample, at r≥0.9, the small stellar velocity dispersion subsample has a higher proportion of galaxies in superclusters ( n≥200) than the large stellar velocity dispersion subsample.

  14. Hα imaging observations of early-type galaxies from the ATLAS3D survey

    Gavazzi, G.; Consolandi, G.; Pedraglio, S.; Fossati, M.; Fumagalli, M.; Boselli, A.

    2018-03-01

    Context. The traditional knowledge of the mechanisms that brought to the formation and evolution of early type galaxies (ETG) in a hierarchical Universe was challenged by the unexpected finding by ATLAS3D that 86% ETGs show signs of a fast rotating disk at their interior, implying an origin common to most spiral galaxies, followed by a quenching phase, while only a minority of the most massive systems are slow rotators and were likely to be the products of merger events. Aims: Our aim is to improve our knowledge on the content and distribution of ionised hydrogen and their usage to form stars in a representative sample of ETGs for which the kinematics and detailed morphological classification were known from ATLAS3D. Methods: Using narrow-band filters centered on the redshifted Hα line along with a broad-band (r-Gunn) filter to recover the stellar continuum, we observed or collected existing imaging observations for 147 ETG (including members of the Virgo cluster), representative of the whole ATLAS3D survey. Results: 55 ETGs (37%) were detected in the Hα line above our detection threshold (HαEW ≤ -1 Å) and 21 harbour a strong source (HαEW ≤ -5 Å) . Conclusions: The strong Hα emitters appear associated with mostly low-mass (M* 1010 M⊙) S0 galaxies which contain conspicuous stellar and gaseous disks, harbouring significant star formation at their interior, including their nuclei. The weak Hα emitters are almost one order of magnitude more massive, contain gas-poor disks and harbour an AGN at their centers. Their emissivity is dominated by [NII] and does not imply star formation. The 92 undetected ETGs constitute the majority in our sample and are gas-free systems which lack a disk and exhibit passive spectra even in their nuclei. These pieces of evidence reinforce the conclusion of Cappellari (2016, ARA&A, 54, 597) that the evolution of ETGs followed the secular channel for the less massive systems and the dry merging channel for the most massive

  15. The Dramatic Size and Kinematic Evolution of Massive Early-type Galaxies

    Lapi, A.; Pantoni, L.; Zanisi, L.; Shi, J.; Mancuso, C.; Massardi, M.; Shankar, F.; Bressan, A.; Danese, L.

    2018-04-01

    We aim to provide a holistic view on the typical size and kinematic evolution of massive early-type galaxies (ETGs) that encompasses their high-z star-forming progenitors, their high-z quiescent counterparts, and their configurations in the local Universe. Our investigation covers the main processes playing a relevant role in the cosmic evolution of ETGs. Specifically, their early fast evolution comprises biased collapse of the low angular momentum gaseous baryons located in the inner regions of the host dark matter halo; cooling, fragmentation, and infall of the gas down to the radius set by the centrifugal barrier; further rapid compaction via clump/gas migration toward the galaxy center, where strong heavily dust-enshrouded star formation takes place and most of the stellar mass is accumulated; and ejection of substantial gas amount from the inner regions by feedback processes, which causes a dramatic puffing-up of the stellar component. In the late slow evolution, passive aging of stellar populations and mass additions by dry merger events occur. We describe these processes relying on prescriptions inspired by basic physical arguments and by numerical simulations to derive new analytical estimates of the relevant sizes, timescales, and kinematic properties for individual galaxies along their evolution. Then we obtain quantitative results as a function of galaxy mass and redshift, and compare them to recent observational constraints on half-light size R e , on the ratio v/σ between rotation velocity and velocity dispersion (for gas and stars) and on the specific angular momentum j ⋆ of the stellar component; we find good consistency with the available multiband data in average values and dispersion, both for local ETGs and for their z ∼ 1–2 star-forming and quiescent progenitors. The outcomes of our analysis can provide hints to gauge sub-grid recipes implemented in simulations, to tune numerical experiments focused on specific processes, and to plan

  16. The SAMI Galaxy Survey: Gravitational Potential and Surface Density Drive Stellar Populations. I. Early-type Galaxies

    Barone, Tania M.; D’Eugenio, Francesco; Colless, Matthew; Scott, Nicholas; van de Sande, Jesse; Bland-Hawthorn, Joss; Brough, Sarah; Bryant, Julia J.; Cortese, Luca; Croom, Scott M.; Foster, Caroline; Goodwin, Michael; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; Lorente, Nuria P. F.; Medling, Anne M.; Owers, Matt S.; Richards, Samuel N.

    2018-03-01

    The well-established correlations between the mass of a galaxy and the properties of its stars are considered to be evidence for mass driving the evolution of the stellar population (SP). However, for early-type galaxies (ETGs), we find that g ‑ i color and stellar metallicity [Z/H] correlate more strongly with gravitational potential Φ than with mass M, whereas SP age correlates best with surface density Σ. Specifically, for our sample of 625 ETGs with integral-field spectroscopy from the Sydney-AAO Multi-object Integral-field Galaxy Survey, compared to correlations with mass, the color–Φ, [Z/H]–Φ, and age–Σ relations show both a smaller scatter and a lower residual trend with galaxy size. For the star formation duration proxy [α/Fe], we find comparable results for trends with Φ and Σ, with both being significantly stronger than the [α/Fe]–M relation. In determining the strength of a trend, we analyze both the overall scatter, and the observational uncertainty on the parameters, in order to compare the intrinsic scatter in each correlation. These results lead us to the following inferences and interpretations: (1) the color–Φ diagram is a more precise tool for determining the developmental stage of the SP than the conventional color–mass diagram; and (2) gravitational potential is the primary regulator of global stellar metallicity, via its relation to the gas escape velocity. Furthermore, we propose the following two mechanisms for the age and [α/Fe] relations with Σ: (a) the age–Σ and [α/Fe]–Σ correlations arise as results of compactness-driven quenching mechanisms; and/or (b) as fossil records of the {{{Σ }}}SFR}\\propto {{{Σ }}}gas} relation in their disk-dominated progenitors.

  17. Galaxy–Galaxy Weak-lensing Measurements from SDSS. I. Image Processing and Lensing Signals

    Luo, Wentao [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Nandan Road 80, Shanghai 200030 (China); Yang, Xiaohu; Zhang, Jun; Tweed, Dylan [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Fu, Liping; Shu, Chenggang [Shanghai Key Lab for Astrophysics, Shanghai Normal University, 100 Guilin Road, 200234, Shanghai (China); Mo, H. J. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States); Bosch, Frank C. van den [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Li, Ran [Key Laboratory for Computational Astrophysics, Partner Group of the Max Planck Institute for Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China); Li, Nan [Department of Astronomy and Astrophysics, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Liu, Xiangkun; Pan, Chuzhong [Department of Astronomy, Peking University, Beijing 100871 (China); Wang, Yiran [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States); Radovich, Mario, E-mail: walt@shao.ac.cn, E-mail: xyang@sjtu.edu.cn [INAF-Osservatorio Astronomico di Napoli, via Moiariello 16, I-80131 Napoli (Italy)

    2017-02-10

    We present our image processing pipeline that corrects the systematics introduced by the point-spread function (PSF). Using this pipeline, we processed Sloan Digital Sky Survey (SDSS) DR7 imaging data in r band and generated a galaxy catalog containing the shape information. Based on our shape measurements of the galaxy images from SDSS DR7, we extract the galaxy–galaxy (GG) lensing signals around foreground spectroscopic galaxies binned in different luminosities and stellar masses. We estimated the systematics, e.g., selection bias, PSF reconstruction bias, PSF dilution bias, shear responsivity bias, and noise rectification bias, which in total is between −9.1% and 20.8% at 2 σ levels. The overall GG lensing signals we measured are in good agreement with Mandelbaum et al. The reduced χ {sup 2} between the two measurements in different luminosity bins are from 0.43 to 0.83. Larger reduced χ {sup 2} from 0.60 to 1.87 are seen for different stellar mass bins, which is mainly caused by the different stellar mass estimator. The results in this paper with higher signal-to-noise ratio are due to the larger survey area than SDSS DR4, confirming that more luminous/massive galaxies bear stronger GG lensing signals. We divide the foreground galaxies into red/blue and star-forming/quenched subsamples and measure their GG lensing signals. We find that, at a specific stellar mass/luminosity, the red/quenched galaxies have stronger GG lensing signals than their counterparts, especially at large radii. These GG lensing signals can be used to probe the galaxy–halo mass relations and their environmental dependences in the halo occupation or conditional luminosity function framework.

  18. Fossil evidence for spin alignment of SDSS galaxies in filaments

    Jones, Bernard J.T.; Weygaert, Rien van de; Arag´on-Calvo, Miguel A.

    2010-01-01

    We search for and find fossil evidence that the distribution of the spin axes of galaxies in cosmic web filaments relative to their host filaments are not randomly distributed. This would indicate that the action of large scale tidal torques effected the alignments of galaxies located in cosmic

  19. E+A galaxies in the SDSS. Stellar population and morphology

    Leiva, R.; Galaz, G.

    2014-10-01

    Galaxies with E+A spectrum have deep Balmer absorption and no H_{α} and [OII] emission. This suggest recent star formation and the lack of ongoing star formation. With an E+A sample from the SDSS DR 7 (Aihara et al. 2011) we study the morphology with Galaxy Zoo 1 data and the star formation history fitting models from Bruzual & Charlot (2003). We found an underpopulation of spiral and disk like galaxies and an overpopulation of interacting galaxies, the last seems consistent with the scenario where, at low z, the interaction mechanism is responsible for at least part of the E+A galaxies. The star formation history (SFH) fits most of the spectra indicating an increased star formation around 2 Gyr in the past. Additional parameters like dust internal extinction need to be included to improve the fitting.

  20. A GMBCG GALAXY CLUSTER CATALOG OF 55,424 RICH CLUSTERS FROM SDSS DR7

    Hao Jiangang; Annis, James; Johnston, David E.; McKay, Timothy A.; Evrard, August; Siegel, Seth R.; Gerdes, David; Koester, Benjamin P.; Rykoff, Eli S.; Rozo, Eduardo; Wechsler, Risa H.; Busha, Michael; Becker, Matthew; Sheldon, Erin

    2010-01-01

    We present a large catalog of optically selected galaxy clusters from the application of a new Gaussian Mixture Brightest Cluster Galaxy (GMBCG) algorithm to SDSS Data Release 7 data. The algorithm detects clusters by identifying the red-sequence plus brightest cluster galaxy (BCG) feature, which is unique for galaxy clusters and does not exist among field galaxies. Red-sequence clustering in color space is detected using an Error Corrected Gaussian Mixture Model. We run GMBCG on 8240 deg 2 of photometric data from SDSS DR7 to assemble the largest ever optical galaxy cluster catalog, consisting of over 55,000 rich clusters across the redshift range from 0.1 < z < 0.55. We present Monte Carlo tests of completeness and purity and perform cross-matching with X-ray clusters and with the maxBCG sample at low redshift. These tests indicate high completeness and purity across the full redshift range for clusters with 15 or more members.

  1. A Study of E+A Galaxies Through SDSS-MaNGA Integral Field Spectroscopy

    Wally, Muhammad; Weaver, Olivia A.; Anderson, Miguel Ricardo; Liu, Allen; Falcone, Julia; Wallack, Nicole Lisa; James, Olivia; Liu, Charles

    2017-01-01

    We outline the selection process and analysis of sixteen E+A galaxies observed by the Mapping Nearby Galaxies at the Apache Point Observatory (MaNGA) survey as a part of the fourth generation of the Sloan Digital Sky Survey (SDSS-IV). We present their Integral field spectroscopy and analyze their spatial distribution of stellar ages, metallicities and other stellar population properties. We can potentially study the variation in these properties as a function of redshift. This work was supported by the Alfred P. Sloan Foundation via the SDSS-IV Faculty and Student Team (FAST) initiative, ARC Agreement #SSP483 to the CUNY College of Staten Island. This work was also supported by grants to The American Museum of Natural History, and the CUNY College of Staten Island through The National Science Foundation.

  2. The ATLAS(3D) project : XIX. The hot gas content of early-type galaxies: fast versus slow rotators

    Sarzi, Marc; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frederic; Bureau, Martin; Cappellari, Michele; Crocker, Alison; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnovic, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Scott, Nicholas; Serra, Paolo; Young, Lisa M.; Weijmans, Anne-Marie

    2013-01-01

    For early-type galaxies, the ability to sustain a corona of hot, X-ray-emitting gas could have played a key role in quenching their star formation history. A halo of hot gas may act as an effective shield against the acquisition of cold gas and can quickly absorb stellar mass loss material. Yet,

  3. The ATLAS3D project - XIX. The hot gas content of early-type galaxies: fast versus slow rotators

    Sarzi, Marc; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Cappellari, Michele; Crocker, Alison; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Scott, Nicholas; Serra, Paolo; Young, Lisa M.; Weijmans, Anne-Marie

    For early-type galaxies, the ability to sustain a corona of hot, X-ray-emitting gas could have played a key role in quenching their star formation history. A halo of hot gas may act as an effective shield against the acquisition of cold gas and can quickly absorb stellar mass loss material. Yet,

  4. The ATLAS3D Project - XXX. Star formation histories and stellar population scaling relations of early-type galaxies

    McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bournaud, Frédéric; Bureau, Martin; Cappellari, Michele; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    We present the stellar population content of early-type galaxies from the ATLAS3D survey. Using spectra integrated within apertures covering up to one effective radius, we apply two methods: one based on measuring line-strength indices and applying single stellar population (SSP) models to derive

  5. Strong gravitational lensing and the stellar IMF of early-type galaxies

    Leier, Dominik; Ferreras, Ignacio; Saha, Prasenjit; Charlot, Stéphane; Bruzual, Gustavo; La Barbera, Francesco

    2016-07-01

    Systematic variations of the initial mass function (IMF) in early-type galaxies, and their connection with possible drivers such as velocity dispersion or metallicity, have been much debated in recent years. Strong lensing over galaxy scales combined with photometric and spectroscopic data provides a powerful method to constrain the stellar mass-to-light ratio and hence the functional form of the IMF. We combine photometric and spectroscopic constraints from the latest set of population synthesis models of Charlot & Bruzual, including a varying IMF, with a non-parametric analysis of the lens masses of 18 ETGs from the SLACS survey, with velocity dispersions in the range 200-300 km s-1. We find that very bottom-heavy IMFs are excluded. However, the upper limit to the bimodal IMF slope (μ ≲ 2.2, accounting for a dark matter fraction of 20-30 per cent, where μ = 1.3 corresponds to a Kroupa-like IMF) is compatible at the 1σ level with constraints imposed by gravity-sensitive line strengths. A two-segment power-law parametrization of the IMF (Salpeter-like for high masses) is more constrained (Γ ≲ 1.5, where Γ is the power index at low masses) but requires a dark matter contribution of ≳25 per cent to reconcile the results with a Salpeter IMF. For a standard Milky Way-like IMF to be applicable, a significant dark matter contribution is required within 1Re. Our results reveal a large range of allowed IMF slopes, which, when interpreted as intrinsic scatter in the IMF properties of ETGs, could explain the recent results of Smith et al., who find Milky Way-like IMF normalizations in a few massive lensing ETGs.

  6. The 3D Power Spectrum from Angular Clustering of Galaxies in Early SDSS Data

    Dodelson, Scott; Tegmark, Max; Scranton, Ryan; Budavari, Tamas; Connolly, Andrew; Csabai, Istvan; Eisenstein, Daniel; Frieman, Joshua A.; Gunn, James E.; Hui, Lam; Jain, Bhuvnesh; Johnston, David; Kent, Stephen M.; Loveday, Jon; Nichol, Robert C.; O'Connell, Liam; Scoccimarro, Roman; Sheth, Ravi K.; Stebbins, Albert; Strauss, Michael A.; Szalay, Alexander S.; Szapudi, Istvan; Vogeley, Michael S.; Zehavi, Idit; Annis, James; Bahcall, Neta A.; Brinkman, Jon; Doi, Mamoru; Fukugita, Masataka; Hennessy, Greg; Ivezic, Zeljko; Knapp, Gillian R.; Kunszt, Peter; Lamb, Don Q.; Lee, Brian C.; Lupton, Robert H.; Munn, Jeffrey A.; Peoples, John; Pier, Jeffrey R.; Rockosi, Constance; Schlegel, David; Stoughton, Christopher; Tucker, Douglas L.; Yanny, Brian; York, Donald G.; Dodelson, Scott; Narayanan, Vijay K.; Tegmark, Max; Scranton, Ryan; Budavari, Tamas; Connolly, Andrew; Csabai, Istvan; Eisenstein, Daniel; Frieman, Joshua A.; Gunn, James E.; Hui, Lam; Jain, Bhuvnesh; Johnston, David; Kent, Stephen; Loveday, Jon; Nichol, Robert C.; Connell, Liam O'; Scoccimarro, Roman; Sheth, Ravi K.; Stebbins, Albert; Strauss, Michael A.; Szalay, Alexander S.; Szapudi, Istv\\'an; Vogeley, Michael S.; Zehavi, Idit

    2001-01-01

    Early photometric data from the Sloan Digital Sky Survey (SDSS) contain angular positions for 1.5 million galaxies. In companion papers, the angular correlation function $w(\\theta)$ and 2D power spectrum $C_l$ of these galaxies are presented. Here we invert Limber's equation to extract the 3D power spectrum from the angular results. We accomplish this using an estimate of $dn/dz$, the redshift distribution of galaxies in four different magnitude slices in the SDSS photometric catalog. The resulting 3D power spectrum estimates from $w(\\theta)$ and $C_l$ agree with each other and with previous estimates over a range in wavenumbers $0.03 < k/{\\rm h Mpc}^{-1} < 1$. The galaxies in the faintest magnitude bin ($21 < \\rstar < 22$, which have median redshift $z_m=0.43$) are less clustered than the galaxies in the brightest magnitude bin ($18 < \\rstar < 19$ with $z_m=0.17$), especially on scales where nonlinearities are important. The derived power spectrum agrees with that of Szalay et al. (2001) wh...

  7. Evolution of Late-type Galaxies in a Cluster Environment: Effects of High-speed Multiple Encounters with Early-type Galaxies

    Hwang, Jeong-Sun; Park, Changbom; Banerjee, Arunima; Hwang, Ho Seong

    2018-04-01

    Late-type galaxies falling into a cluster would evolve being influenced by the interactions with both the cluster and the nearby cluster member galaxies. Most numerical studies, however, tend to focus on the effects of the former with little work done on those of the latter. We thus perform a numerical study on the evolution of a late-type galaxy interacting with neighboring early-type galaxies at high speed using hydrodynamic simulations. Based on the information obtained from the Coma cluster, we set up the simulations for the case where a Milky Way–like late-type galaxy experiences six consecutive collisions with twice as massive early-type galaxies having hot gas in their halos at the closest approach distances of 15–65 h ‑1 kpc at the relative velocities of 1500–1600 km s‑1. Our simulations show that the evolution of the late-type galaxy can be significantly affected by the accumulated effects of the high-speed multiple collisions with the early-type galaxies, such as on cold gas content and star formation activity of the late-type galaxy, particularly through the hydrodynamic interactions between cold disk and hot gas halos. We find that the late-type galaxy can lose most of its cold gas after the six collisions and have more star formation activity during the collisions. By comparing our simulation results with those of galaxy–cluster interactions, we claim that the role of the galaxy–galaxy interactions on the evolution of late-type galaxies in clusters could be comparable with that of the galaxy–cluster interactions, depending on the dynamical history.

  8. Probing evolutionary population synthesis models in the near infrared with early-type galaxies

    Dahmer-Hahn, Luis Gabriel; Riffel, Rogério; Rodríguez-Ardila, Alberto; Martins, Lucimara P.; Kehrig, Carolina; Heckman, Timothy M.; Pastoriza, Miriani G.; Dametto, Natacha Z.

    2018-06-01

    We performed a near-infrared (NIR; ˜1.0 -2.4 μm) stellar population study in a sample of early-type galaxies. The synthesis was performed using five different evolutionary population synthesis libraries of models. Our main results can be summarized as follows: low-spectral-resolution libraries are not able to produce reliable results when applied to the NIR alone, with each library finding a different dominant population. The two newest higher resolution models, on the other hand, perform considerably better, finding consistent results to each other and to literature values. We also found that optical results are consistent with each other even for lower resolution models. We also compared optical and NIR results and found out that lower resolution models tend to disagree in the optical and in the NIR, with higher fraction of young populations in the NIR and dust extinction ˜1 mag higher than optical values. For higher resolution models, optical and NIR results tend to agree much better, suggesting that a higher spectral resolution is fundamental to improve the quality of the results.

  9. THE ORIGIN OF DUST IN EARLY-TYPE GALAXIES AND IMPLICATIONS FOR ACCRETION ONTO SUPERMASSIVE BLACK HOLES

    Martini, Paul [Department of Astronomy and Center for Cosmology and Astroparticle Physics, The Ohio State University, Columbus, OH 43210 (United States); Dicken, Daniel [Institut de Astrophysique Spatiale, Paris (France); Storchi-Bergmann, Thaisa [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Caixa Postal 15051, 91501-970 Porto Alegre, RS (Brazil)

    2013-04-01

    We have conducted an archival Spitzer study of 38 early-type galaxies in order to determine the origin of the dust in approximately half of this population. Our sample galaxies generally have good wavelength coverage from 3.6 {mu}m to 160 {mu}m, as well as visible-wavelength Hubble Space Telescope (HST) images. We use the Spitzer data to estimate dust masses, or establish upper limits, and find that all of the early-type galaxies with dust lanes in the HST data are detected in all of the Spitzer bands and have dust masses of {approx}10{sup 5}-10{sup 6.5} M{sub Sun }, while galaxies without dust lanes are not detected at 70 {mu}m and 160 {mu}m and typically have <10{sup 5} M{sub Sun} of dust. The apparently dust-free galaxies do have 24 {mu}m emission that scales with the shorter-wavelength flux, yet substantially exceeds the expectations of photospheric emission by approximately a factor of three. We conclude this emission is dominated by hot, circumstellar dust around evolved stars that does not survive to form a substantial interstellar component. The order-of-magnitude variations in dust masses between galaxies with similar stellar populations rule out a substantial contribution from continual, internal production in spite of the clear evidence for circumstellar dust. We demonstrate that the interstellar dust is not due to purely external accretion, unless the product of the merger rate of dusty satellites and the dust lifetime is at least an order of magnitude higher than expected. We propose that dust in early-type galaxies is seeded by external accretion, yet the accreted dust is maintained by continued growth in externally accreted cold gas beyond the nominal lifetime of individual grains. The several Gyr depletion time of the cold gas is long enough to reconcile the fraction of dusty early-type galaxies with the merger rate of gas-rich satellites. As the majority of dusty early-type galaxies are also low-luminosity active galactic nuclei and likely fueled

  10. Multiple populations within globular clusters in Early-type galaxies Exploring their effect on stellar initial mass function estimates

    Chantereau, W.; Usher, C.; Bastian, N.

    2018-05-01

    It is now well-established that most (if not all) ancient globular clusters host multiple populations, that are characterised by distinct chemical features such as helium abundance variations along with N-C and Na-O anti-correlations, at fixed [Fe/H]. These very distinct chemical features are similar to what is found in the centres of the massive early-type galaxies and may influence measurements of the global properties of the galaxies. Additionally, recent results have suggested that M/L variations found in the centres of massive early-type galaxies might be due to a bottom-heavy stellar initial mass function. We present an analysis of the effects of globular cluster-like multiple populations on the integrated properties of early-type galaxies. In particular, we focus on spectral features in the integrated optical spectrum and the global mass-to-light ratio that have been used to infer variations in the stellar initial mass function. To achieve this we develop appropriate stellar population synthesis models and take into account, for the first time, an initial-final mass relation which takes into consideration a varying He abundance. We conclude that while the multiple populations may be present in massive early-type galaxies, they are likely not responsible for the observed variations in the mass-to-light ratio and IMF sensitive line strengths. Finally, we estimate the fraction of stars with multiple populations chemistry that come from disrupted globular clusters within massive ellipticals and find that they may explain some of the observed chemical patterns in the centres of these galaxies.

  11. VizieR Online Data Catalog: Tully-Fisher relation for SDSS galaxies (Reyes+, 2011)

    Reyes, R.; Mandelbaum, R.; Gunn, J. E.; Pizagno, J.; Lackner, C. N.

    2012-05-01

    In this paper, we derive scaling relations between photometric observable quantities and disc galaxy rotation velocity Vrot or Tully-Fisher relations (TFRs). Our methodology is dictated by our purpose of obtaining purely photometric, minimal-scatter estimators of Vrot applicable to large galaxy samples from imaging surveys. To achieve this goal, we have constructed a sample of 189 disc galaxies at redshifts z<0.1 with long-slit Hα spectroscopy from Pizagno et al. (2007, Cat. J/AJ/134/945) and new observations. By construction, this sample is a fair subsample of a large, well-defined parent disc sample of ~170000 galaxies selected from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). (4 data files).

  12. Galaxy pairs in the SDSS - XIII. The connection between enhanced star formation and molecular gas properties in galaxy mergers

    Violino, Giulio; Ellison, Sara L.; Sargent, Mark; Coppin, Kristen E. K.; Scudder, Jillian M.; Mendel, Trevor J.; Saintonge, Amelie

    2018-05-01

    We investigate the connection between star formation and molecular gas properties in galaxy mergers at low redshift (z ≤ 0.06). The study we present is based on IRAM 30-m CO(1-0) observations of 11 galaxies with a close companion selected from the Sloan Digital Sky Survey (SDSS). The pairs have mass ratios ≤4, projected separations rp ≤ 30 kpc and velocity separations ΔV ≤ 300 km s-1, and have been selected to exhibit enhanced specific star formation rates (sSFRs). We calculate molecular gas (H2) masses, assigning to each galaxy a physically motivated conversion factor αCO, and we derive molecular gas fractions and depletion times. We compare these quantities with those of isolated galaxies from the extended CO Legacy Data base for the GALEX Arecibo SDSS Survey sample (xCOLDGASS; Saintonge et al.) with gas quantities computed in an identical way. Ours is the first study which directly compares the gas properties of galaxy pairs and those of a control sample of normal galaxies with rigorous control procedures and for which SFR and H2 masses have been estimated using the same method. We find that the galaxy pairs have shorter depletion times and an average molecular gas fraction enhancement of 0.4 dex compared to the mass matched control sample drawn from xCOLDGASS. However, the gas masses (and fractions) in galaxy pairs and their depletion times are consistent with those of non-mergers whose SFRs are similarly elevated. We conclude that both external interactions and internal processes may lead to molecular gas enhancement and decreased depletion times.

  13. THE POTENTIAL IMPORTANCE OF BINARY EVOLUTION IN ULTRAVIOLET-OPTICAL SPECTRAL FITTING OF EARLY-TYPE GALAXIES

    Li, Zhongmu; Mao, Caiyan; Chen, Li; Zhang, Qian; Li, Maocai

    2013-01-01

    Most galaxies possibly contain some binaries, and more than half of Galactic hot subdwarf stars, which are thought to be a possible origin of the UV-upturn of old stellar populations, are found in binaries. However, the effect of binary evolution has not been taken into account in most works on the spectral fitting of galaxies. This paper studies the role of binary evolution in the spectral fitting of early-type galaxies, via a stellar population synthesis model including both single and binary star populations. Spectra from ultraviolet to optical bands are fitted to determine a few galaxy parameters. The results show that the inclusion of binaries in stellar population models may lead to obvious change in the determination of some parameters of early-type galaxies and therefore it is potentially important for spectral studies. In particular, the ages of young components of composite stellar populations become much older when using binary star population models instead of single star population models. This implies that binary star population models will measure significantly different star formation histories for early-type galaxies compared to single star population models. In addition, stellar population models with binary interactions on average measure larger dust extinctions than single star population models. This suggests that when binary star population models are used, negative extinctions are possibly no longer necessary in the spectral fitting of galaxies (see previous works, e.g., Cid Fernandes et al. for comparison). Furthermore, it is shown that optical spectra have strong constraints on stellar age while UV spectra have strong constraints on binary fraction. Finally, our results suggest that binary star population models can provide new insight into the stellar properties of globular clusters

  14. THE REDSHIFT EVOLUTION OF OXYGEN AND NITROGEN ABUNDANCES IN EMISSION-LINE SDSS GALAXIES

    Thuan, Trinh X.; Pilyugin, Leonid S.; Zinchenko, Igor A.

    2010-01-01

    The oxygen and nitrogen abundance evolutions with redshift and galaxy stellar mass in emission-line galaxies from the Sloan Digital Sky Survey (SDSS) are investigated. This is the first such study for nitrogen abundances, and it provides an additional constraint for the study of the chemical evolution of galaxies. We have devised a criterion to recognize and exclude from consideration active galactic nuclei and star-forming galaxies with large errors in the line flux measurements. To select star-forming galaxies with accurate line fluxes measurements, we require that, for each galaxy, the nitrogen abundances derived with various calibrations based on different emission lines agree. Using this selection criterion, subsamples of star-forming SDSS galaxies have been extracted from catalogs of the Max-Planck-Institute for Astrophysics/Johns Hopkins University group. We found that the galaxies of highest masses, those with masses ∼>10 11.2 M sun , have not been enriched in both oxygen and nitrogen over the last ∼3 Gyr: they have formed their stars in the so distant past that these have returned their nucleosynthesis products to the interstellar medium before z = 0.25. The galaxies in the mass range from ∼10 11.0 M sun to ∼10 11.2 M sun do not show an appreciable enrichment in oxygen, but do show some enrichment in nitrogen: they also formed their stars before z = 0.25 but later in comparison to the galaxies of highest masses; these stars have not returned nitrogen to the interstellar medium before z = 0.25 because they have not had enough time to evolve. This suggests that stars with lifetimes of 2-3 Gyr, in the 1.5-2 M sun mass range, contribute to the nitrogen production. Finally, galaxies with masses ∼ 11 M sun show enrichment in both oxygen and nitrogen during the last 3 Gyr: they have undergone appreciable star formation and have converted up to ∼20% of their mass into stars over this period. Both oxygen and nitrogen enrichments increase with decreasing

  15. Evidence for a constant initial mass function in early-type galaxies based on their X-ray binary populations

    Peacock, Mark B.; Zepf, Stephen E. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Maccarone, Thomas J. [Texas Tech University, Physics Department, Box 41051, Lubbock, TX 79409 (United States); Kundu, Arunav [Eureka Scientific, Inc., 2452 Delmer Street, Suite 100 Oakland, CA 94602 (United States); Gonzalez, Anthony H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Lehmer, Bret D. [The Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States); Maraston, Claudia, E-mail: mpeacock@msu.edu [Institute of Cosmology and Gravitation, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom)

    2014-04-01

    A number of recent studies have proposed that the stellar initial mass function (IMF) of early type galaxies varies systematically as a function of galaxy mass, with higher mass galaxies having bottom-heavy IMFs. These bottom-heavy IMFs have more low-mass stars relative to the number of high mass stars, and therefore naturally result in proportionally fewer neutron stars (NSs) and black holes (BHs). In this paper, we specifically predict the variation in the number of BHs and NSs based on the power-law IMF variation required to reproduce the observed mass-to-light ratio trends with galaxy mass. We then test whether such variations are observed by studying the field low-mass X-ray binary (LMXB) populations of nearby early-type galaxies. In these binaries, an NS or BH accretes matter from a low-mass donor star. Their number is therefore expected to scale with the number of BHs and NSs present in a galaxy. We find that the number of LMXBs per K-band light is similar among the galaxies in our sample. These data therefore demonstrate the uniformity of the slope of the IMF from massive stars down to those now dominating the K-band light and are consistent with an invariant IMF. Our results are inconsistent with an IMF which varies from a Kroupa/Chabrier like IMF for low-mass galaxies to a steep power-law IMF (with slope x = 2.8) for high mass galaxies. We discuss how these observations constrain the possible forms of the IMF variations and how future Chandra observations can enable sharper tests of the IMF.

  16. Evidence for a constant initial mass function in early-type galaxies based on their X-ray binary populations

    Peacock, Mark B.; Zepf, Stephen E.; Maccarone, Thomas J.; Kundu, Arunav; Gonzalez, Anthony H.; Lehmer, Bret D.; Maraston, Claudia

    2014-01-01

    A number of recent studies have proposed that the stellar initial mass function (IMF) of early type galaxies varies systematically as a function of galaxy mass, with higher mass galaxies having bottom-heavy IMFs. These bottom-heavy IMFs have more low-mass stars relative to the number of high mass stars, and therefore naturally result in proportionally fewer neutron stars (NSs) and black holes (BHs). In this paper, we specifically predict the variation in the number of BHs and NSs based on the power-law IMF variation required to reproduce the observed mass-to-light ratio trends with galaxy mass. We then test whether such variations are observed by studying the field low-mass X-ray binary (LMXB) populations of nearby early-type galaxies. In these binaries, an NS or BH accretes matter from a low-mass donor star. Their number is therefore expected to scale with the number of BHs and NSs present in a galaxy. We find that the number of LMXBs per K-band light is similar among the galaxies in our sample. These data therefore demonstrate the uniformity of the slope of the IMF from massive stars down to those now dominating the K-band light and are consistent with an invariant IMF. Our results are inconsistent with an IMF which varies from a Kroupa/Chabrier like IMF for low-mass galaxies to a steep power-law IMF (with slope x = 2.8) for high mass galaxies. We discuss how these observations constrain the possible forms of the IMF variations and how future Chandra observations can enable sharper tests of the IMF.

  17. Flying across Galaxy Clusters with Google Earth: additional imagery from SDSS co-added data

    Hao, Jiangang; Annis, James; /Fermilab

    2010-10-01

    Galaxy clusters are spectacular. We provide a Google Earth compatible imagery for the deep co-added images from the Sloan Digital Sky Survey and make it a tool for examing galaxy clusters. Google Earth (in sky mode) provides a highly interactive environment for visualizing the sky. By encoding the galaxy cluster information into a kml/kmz file, one can use Google Earth as a tool for examining galaxy clusters and fly across them freely. However, the resolution of the images provided by Google Earth is not very high. This is partially because the major imagery google earth used is from Sloan Digital Sky Survey (SDSS) (SDSS collaboration 2000) and the resolutions have been reduced to speed up the web transferring. To have higher resolution images, you need to add your own images in a way that Google Earth can understand. The SDSS co-added data are the co-addition of {approx}100 scans of images from SDSS stripe 82 (Annis et al. 2010). It provides the deepest images based on SDSS and reach as deep as about redshift 1.0. Based on the co-added images, we created color images in a way as described by Lupton et al. (2004) and convert the color images to Google Earth compatible images using wcs2kml (Brewer et al. 2007). The images are stored at a public server at Fermi National Accelerator Laboratory and can be accessed by the public. To view those images in Google Earth, you need to download a kmz file, which contains the links to the color images, and then open the kmz file with your Google Earth. To meet different needs for resolutions, we provide three kmz files corresponding to low, medium and high resolution images. We recommend the high resolution one as long as you have a broadband Internet connection, though you should choose to download any of them, depending on your own needs and Internet speed. After you open the downloaded kmz file with Google Earth (in sky mode), it takes about 5 minutes (depending on your Internet connection and the resolution of images you

  18. Flying across Galaxy Clusters with Google Earth: additional imagery from SDSS co-added data

    Hao, Jiangang; Annis, James

    2010-01-01

    Galaxy clusters are spectacular. We provide a Google Earth compatible imagery for the deep co-added images from the Sloan Digital Sky Survey and make it a tool for examing galaxy clusters. Google Earth (in sky mode) provides a highly interactive environment for visualizing the sky. By encoding the galaxy cluster information into a kml/kmz file, one can use Google Earth as a tool for examining galaxy clusters and fly across them freely. However, the resolution of the images provided by Google Earth is not very high. This is partially because the major imagery google earth used is from Sloan Digital Sky Survey (SDSS) (SDSS collaboration 2000) and the resolutions have been reduced to speed up the web transferring. To have higher resolution images, you need to add your own images in a way that Google Earth can understand. The SDSS co-added data are the co-addition of ∼100 scans of images from SDSS stripe 82 (Annis et al. 2010). It provides the deepest images based on SDSS and reach as deep as about redshift 1.0. Based on the co-added images, we created color images in a way as described by Lupton et al. (2004) and convert the color images to Google Earth compatible images using wcs2kml (Brewer et al. 2007). The images are stored at a public server at Fermi National Accelerator Laboratory and can be accessed by the public. To view those images in Google Earth, you need to download a kmz file, which contains the links to the color images, and then open the kmz file with your Google Earth. To meet different needs for resolutions, we provide three kmz files corresponding to low, medium and high resolution images. We recommend the high resolution one as long as you have a broadband Internet connection, though you should choose to download any of them, depending on your own needs and Internet speed. After you open the downloaded kmz file with Google Earth (in sky mode), it takes about 5 minutes (depending on your Internet connection and the resolution of images you want

  19. ULTRALUMINOUS INFRARED GALAXIES IN THE WISE AND SDSS SURVEYS

    Su, Shanshan; Kong, Xu; Li, Jinrong; Fang, Guanwen

    2013-01-01

    In this paper, we present a large catalog of 419 Ultraluminous infrared galaxies (ULIRGs), carefully selected from the Wide-field Infrared Survey Explorer mid-infrared data and the Sloan Digital Sky Survey eighth data release, and classify them into three subsamples, based on their emission line properties: H II-like ULIRGs, Seyfert 2 ULIRGs, and composite ULIRGs. We apply our new efficient spectral synthesis technique, which is based on mean field approach to Bayesian independent component analysis (MF-ICA) method, to the galaxy integrated spectra. We also analyze the stellar population properties, including percentage contribution, stellar age, and stellar mass, for these three types of ULIRGs, and explore the evolution among them. We find no significant difference between the properties of stellar populations in ULIRGs with or without active galactic nucleus components. Our results suggest that there is no evolutionary link among these three type ULIRGs

  20. Improving galaxy morphologies for SDSS with Deep Learning

    Domínguez Sánchez, H.; Huertas-Company, M.; Bernardi, M.; Tuccillo, D.; Fischer, J. L.

    2018-05-01

    We present a morphological catalogue for ˜670 000 galaxies in the Sloan Digital Sky Survey in two flavours: T-type, related to the Hubble sequence, and Galaxy Zoo 2 (GZ2 hereafter) classification scheme. By combining accurate existing visual classification catalogues with machine learning, we provide the largest and most accurate morphological catalogue up to date. The classifications are obtained with Deep Learning algorithms using Convolutional Neural Networks (CNNs). We use two visual classification catalogues, GZ2 and Nair & Abraham (2010), for training CNNs with colour images in order to obtain T-types and a series of GZ2 type questions (disc/features, edge-on galaxies, bar signature, bulge prominence, roundness, and mergers). We also provide an additional probability enabling a separation between pure elliptical (E) from S0, where the T-type model is not so efficient. For the T-type, our results show smaller offset and scatter than previous models trained with support vector machines. For the GZ2 type questions, our models have large accuracy (>97 per cent), precision and recall values (>90 per cent), when applied to a test sample with the same characteristics as the one used for training. The catalogue is publicly released with the paper.

  1. DISSECTING THE RED SEQUENCE. II. STAR FORMATION HISTORIES OF EARLY-TYPE GALAXIES THROUGHOUT THE FUNDAMENTAL PLANE

    Graves, Genevieve J.; Faber, S. M.; Schiavon, Ricardo P.

    2009-01-01

    This analysis uses spectra of ∼16,000 nearby Sloan Digital Sky Survey quiescent galaxies to track variations in galaxy star formation histories (SFHs) along and perpendicular to the fundamental plane (FP). We sort galaxies by their FP properties (σ, R e , and I e ) and construct high signal-to-noise ratio mean galaxy spectra that span the breadth and thickness of the FP. From these spectra, we determine mean luminosity-weighted ages, [Fe/H], [Mg/H], and [Mg/Fe] based on single stellar population models using the method described in Graves and Schiavon. In agreement with previous work, the SFHs of early-type galaxies are found to form a two-parameter family. The major trend is that mean age, [Fe/H], [Mg/H], and [Mg/Fe] all increase with σ. However, no stellar population property shows any dependence on R e at fixed σ, suggesting that σ and not dynamical mass (M dyn ∝ σ 2 R e ) is the better predictor of past SFH. In addition to the main trend with σ, galaxies also show a range of population properties at fixed σ that are strongly correlated with surface brightness residuals from the FP (Δlog I e ), such that higher surface brightness galaxies have younger mean ages, higher [Fe/H], higher [Mg/H], and lower [Mg/Fe] than lower surface brightness galaxies. These latter trends are a major new constraint on SFHs.

  2. E+A Galaxy Properties and Post-Starburst Galaxy Evolution Data through SDSS-IV MaNGA and Illustris: A Co-Analysis

    Ojanen, Winonah; Dudley, Raymond; Edwards, Kay; Gonzalez, Andrea; Johnson, Amalya; Kerrison, Nicole; Marinelli, Mariarosa; Melchert, Nancy; Liu, Charles; Sloan Collaboration, SDSS-IV MaNGA

    2018-01-01

    E+A galaxies (Elliptical + A-type stars) are post-starburst galaxies that have experienced a sudden quenching phase. Using previous research methods, 39 candidates out of 2,812 galaxies observed, or 1.4%, were selected from the SDSS-IV MaNGA survey. We then identified morphological characteristics of the 39 galaxies including stellar kinematics, Gini coefficient, gas density and distribution and stellar ages. To study the origin of how E+A galaxies evolved to their present state, galaxy simulation data from the Illustris simulation was utilized to identify similar quenched post-starburst candidates. Seven post-starburst candidates were identified through star formation rate histories of Illustris simulated galaxies. The evolution of these galaxies is studied from 0 to 13.8 billion years ago to identify what caused the starburst and quenching of the Illustris candidates. Similar morphological characteristics of Illustris post-starburst candidates are pulled from before, during, and post-starburst and compared to the same morphological characteristics of the E+A galaxies from SDSS-IV MaNGA. The characteristics and properties of the Illustris galaxies are used to identify the possible evolutionary histories of the observed E+A galaxies. This work was supported by grants AST-1460860 from the National Science Foundation and SDSS FAST/SSP-483 from the Alfred P. Sloan Foundation to the CUNY College of Staten Island.

  3. The Stellar Kinematics of E+A Galaxies in SDSS IV-MaNGA

    Johnson, Amalya; Dudley, Raymond; Edwards, Kay; Gonzalez, Andrea; Kerrison, Nicole; Marinelli, Mariarosa; Melchert, Nancy; Ojanen, Winonah; Liu, Charles; SDSS-IV MaNGA

    2018-01-01

    E+A galaxies, hypothesized to be “transition” galaxies between the blue cloud and the red sequence, are valuable sources for studying the evolution of galaxies. Using data from the Sloan Digital Sky Survey Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, a large scale integral field spectroscopic survey of nearby galaxies from 3600 to 10300 Å, we identifed galaxies that exhibitted E+A characteristics within their optical spectra. We analyzed the 2,812 galaxies thus far observed by MaNGA to identify those that showed evidence of a starburst about 1 billion years ago, followed by cessation of star formation and quenching of the galaxy. Through this process we identifed 39 E+A galaxies by directly looking at the optical spectra and ensuring they exhibited the necessary properties of an E+A spectra, including a strong break at the 4000 Å mark, little to no Hα emission and absorption through the Balmer series, and a blue slope of the continuum past ~5000 Å as the flux decreases. We analyzed the stellar kinematics of these galaxies to determine whether or not they were fast or slow rotators, a proposed indicator of a major merger in their recent past. Using Voronoi binned graphs from the MaNGA Marvin database, we measured their stellar rotation curves in order to more clearly show the range of velocities within the galaxies. Among our 39 E+A candidates, all but two exhibited significant, orderly rotation across the galaxy, and 29 out of 39 of our galaxies show rotation faster than 30 km/s. With the caveat that our selection process was biased toward galaxies with orderly rotation, this prevalence of rotation challenges the belief that all E+A galaxies are created from major mergers. This work was supported by grants AST-1460860 from the National Science Foundation and SDSS FAST/SSP-483 from the Alfred P. Sloan Foundation to the CUNY College of Staten Island.

  4. PHOTOMETRIC REDSHIFT PROBABILITY DISTRIBUTIONS FOR GALAXIES IN THE SDSS DR8

    Sheldon, Erin S.; Cunha, Carlos E.; Mandelbaum, Rachel; Brinkmann, J.; Weaver, Benjamin A.

    2012-01-01

    We present redshift probability distributions for galaxies in the Sloan Digital Sky Survey (SDSS) Data Release 8 imaging data. We used the nearest-neighbor weighting algorithm to derive the ensemble redshift distribution N(z), and individual redshift probability distributions P(z) for galaxies with r < 21.8 and u < 29.0. As part of this technique, we calculated weights for a set of training galaxies with known redshifts such that their density distribution in five-dimensional color-magnitude space was proportional to that of the photometry-only sample, producing a nearly fair sample in that space. We estimated the ensemble N(z) of the photometric sample by constructing a weighted histogram of the training-set redshifts. We derived P(z)'s for individual objects by using training-set objects from the local color-magnitude space around each photometric object. Using the P(z) for each galaxy can reduce the statistical error in measurements that depend on the redshifts of individual galaxies. The spectroscopic training sample is substantially larger than that used for the DR7 release. The newly added PRIMUS catalog is now the most important training set used in this analysis by a wide margin. We expect the primary sources of error in the N(z) reconstruction to be sample variance and spectroscopic failures: The training sets are drawn from relatively small volumes of space, and some samples have large incompleteness. Using simulations we estimated the uncertainty in N(z) due to sample variance at a given redshift to be ∼10%-15%. The uncertainty on calculations incorporating N(z) or P(z) depends on how they are used; we discuss the case of weak lensing measurements. The P(z) catalog is publicly available from the SDSS Web site.

  5. The catalog of edge-on disk galaxies from SDSS. I. The catalog and the structural parameters of stellar disks

    Bizyaev, D. V. [Apache Point Observatory and New Mexico State University, Sunspot, NM, 88349 (United States); Kautsch, S. J. [Nova Southeastern University, Fort Lauderdale, FL 33314 (United States); Mosenkov, A. V. [Central Astronomical Observatory of RAS (Russian Federation); Reshetnikov, V. P.; Sotnikova, N. Ya.; Yablokova, N. V. [St. Petersburg State University (Russian Federation); Hillyer, R. W. [Christopher Newport University, Newport News, VA 23606 (United States)

    2014-05-20

    We present a catalog of true edge-on disk galaxies automatically selected from the Seventh Data Release of the Sloan Digital Sky Survey (SDSS). A visual inspection of the g, r, and i images of about 15,000 galaxies allowed us to split the initial sample of edge-on galaxy candidates into 4768 (31.8% of the initial sample) genuine edge-on galaxies, 8350 (55.7%) non-edge-on galaxies, and 1865 (12.5%) edge-on galaxies not suitable for simple automatic analysis because these objects either show signs of interaction and warps, or nearby bright stars project on it. We added more candidate galaxies from RFGC, EFIGI, RC3, and Galaxy Zoo catalogs found in the SDSS footprints. Our final sample consists of 5747 genuine edge-on galaxies. We estimate the structural parameters of the stellar disks (the stellar disk thickness, radial scale length, and central surface brightness) in the galaxies by analyzing photometric profiles in each of the g, r, and i images. We also perform simplified three-dimensional modeling of the light distribution in the stellar disks of edge-on galaxies from our sample. Our large sample is intended to be used for studying scaling relations in the stellar disks and bulges and for estimating parameters of the thick disks in different types of galaxies via the image stacking. In this paper, we present the sample selection procedure and general description of the sample.

  6. SDSS-IV MaNGA: Stellar angular momentum of about 2300 galaxies: unveiling the bimodality of massive galaxy properties

    Graham, Mark T.; Cappellari, Michele; Li, Hongyu; Mao, Shude; Bershady, Matthew; Bizyaev, Dmitry; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Drory, Niv; Law, David R.; Pan, Kaike; Thomas, Daniel; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.; Yan, Renbin

    2018-03-01

    We measure λ _{R_e}, a proxy for galaxy specific stellar angular momentum within one effective radius, and the ellipticity, ɛ, for about 2300 galaxies of all morphological types observed with integral field spectroscopy as part of the MaNGA survey, the largest such sample to date. We use the (λ _{R_e}, ɛ ) diagram to separate early-type galaxies into fast and slow rotators. We also visually classify each galaxy according to its optical morphology and two-dimensional stellar velocity field. Comparing these classifications to quantitative λ _{R_e} measurements reveals tight relationships between angular momentum and galaxy structure. In order to account for atmospheric seeing, we use realistic models of galaxy kinematics to derive a general approximate analytic correction for λ _{R_e}. Thanks to the size of the sample and the large number of massive galaxies, we unambiguously detect a clear bimodality in the (λ _{R_e}, ɛ ) diagram which may result from fundamental differences in galaxy assembly history. There is a sharp secondary density peak inside the region of the diagram with low λ _{R_e} and ɛ their distribution of the misalignments between the photometric and kinematic position angles. We confirm that genuine slow rotators start appearing above M ≥ 2 × 1011M⊙ where a significant number of high-mass fast rotators also exist.

  7. THE OPTICAL AFTERGLOW AND z = 0.92 EARLY-TYPE HOST GALAXY OF THE SHORT GRB 100117A

    Fong, W.; Berger, E.; Chornock, R.; Tanvir, N. R.; Levan, A. J.; Fruchter, A. S.; Graham, J. F.; Cucchiara, A.; Fox, D. B.

    2011-01-01

    We present the discovery of the optical afterglow and early-type host galaxy of the short-duration GRB 100117A. The faint afterglow is detected 8.3 hr after the burst with r AB = 25.46 ± 0.20 mag. Follow-up optical and near-infrared observations uncover a coincident compact red galaxy, identified as an early-type galaxy at a spectroscopic redshift of z ∼ 0.915 with a mass of ∼3 x 10 10 M sun , an age of ∼1 Gyr, and a luminosity of L B ≅ 0.5 L * . From a possible weak detection of [O II]λ3727 emission at z = 0.915 we infer an upper bound on the star formation rate of ∼0.1 M sun yr -1 , leading to a specific star formation rate of ∼ -1 . Thus, GRB 100117A is only the second short burst to date with a secure early-type host (the other being GRB 050724 at z = 0.257) and it has one of the highest short gamma-ray burst (GRB) redshifts. The offset between the host center and the burst position, 470 ± 310 pc, is the smallest to date. Combined with the old stellar population age, this indicates that the burst likely originated from a progenitor with no significant kick velocity. However, from the brightness of the optical afterglow we infer a relatively low density of n ∼ 3 x 10 -4 ε -3 e,-1 ε -1.75 B,-1 cm -3 . The combination of an optically faint afterglow and host suggests that previous such events may have been missed, thereby potentially biasing the known short GRB host population against z ∼> 1 early-type hosts.

  8. The ATLAS3D Project - XXX. Star formation histories and stellar population scaling relations of early-type galaxies

    McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bournaud, Frédéric; Bureau, Martin; Cappellari, Michele; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2015-04-01

    We present the stellar population content of early-type galaxies from the ATLAS3D survey. Using spectra integrated within apertures covering up to one effective radius, we apply two methods: one based on measuring line-strength indices and applying single stellar population (SSP) models to derive SSP-equivalent values of stellar age, metallicity, and alpha enhancement; and one based on spectral fitting to derive non-parametric star formation histories, mass-weighted average values of age, metallicity, and half-mass formation time-scales. Using homogeneously derived effective radii and dynamically determined galaxy masses, we present the distribution of stellar population parameters on the Mass Plane (MJAM, σe, R^maj_e), showing that at fixed mass, compact early-type galaxies are on average older, more metal-rich, and more alpha-enhanced than their larger counterparts. From non-parametric star formation histories, we find that the duration of star formation is systematically more extended in lower mass objects. Assuming that our sample represents most of the stellar content of today's local Universe, approximately 50 per cent of all stars formed within the first 2 Gyr following the big bang. Most of these stars reside today in the most massive galaxies (>1010.5 M⊙), which themselves formed 90 per cent of their stars by z ˜ 2. The lower mass objects, in contrast, have formed barely half their stars in this time interval. Stellar population properties are independent of environment over two orders of magnitude in local density, varying only with galaxy mass. In the highest density regions of our volume (dominated by the Virgo cluster), galaxies are older, alpha-enhanced, and have shorter star formation histories with respect to lower density regions.

  9. The Stellar Initial Mass Function in Early-type Galaxies from Absorption Line Spectroscopy. I. Data and Empirical Trends

    van Dokkum, Pieter G.; Conroy, Charlie

    2012-11-01

    The strength of gravity-sensitive absorption lines in the integrated light of old stellar populations is one of the few direct probes of the stellar initial mass function (IMF) outside of the Milky Way. Owing to the advent of fully depleted CCDs with little or no fringing it has recently become possible to obtain accurate measurements of these features. Here, we present spectra covering the wavelength ranges 0.35-0.55 μm and 0.72-1.03 μm for the bulge of M31 and 34 early-type galaxies from the SAURON sample, obtained with the Low Resolution Imaging Spectrometer on Keck. The signal-to-noise ratio is >~ 200 Å-1 out to 1 μm, which is sufficient to measure gravity-sensitive features for individual galaxies and to determine how they depend on other properties of the galaxies. Combining the new data with previously obtained spectra for globular clusters in M31 and the most massive elliptical galaxies in the Virgo cluster, we find that the dwarf-sensitive Na I λ8183, 8195 doublet and the FeH λ9916 Wing-Ford band increase systematically with velocity dispersion, while the giant-sensitive Ca II λ8498, 8542, 8662 triplet decreases with dispersion. These trends are consistent with a varying IMF, such that galaxies with deeper potential wells have more dwarf-enriched mass functions. In a companion paper, we use a comprehensive stellar population synthesis model to demonstrate that IMF effects can be separated from age and abundance variations and quantify the IMF variation among early-type galaxies.

  10. THE STELLAR INITIAL MASS FUNCTION IN EARLY-TYPE GALAXIES FROM ABSORPTION LINE SPECTROSCOPY. I. DATA AND EMPIRICAL TRENDS

    Van Dokkum, Pieter G.; Conroy, Charlie

    2012-01-01

    The strength of gravity-sensitive absorption lines in the integrated light of old stellar populations is one of the few direct probes of the stellar initial mass function (IMF) outside of the Milky Way. Owing to the advent of fully depleted CCDs with little or no fringing it has recently become possible to obtain accurate measurements of these features. Here, we present spectra covering the wavelength ranges 0.35-0.55 μm and 0.72-1.03 μm for the bulge of M31 and 34 early-type galaxies from the SAURON sample, obtained with the Low Resolution Imaging Spectrometer on Keck. The signal-to-noise ratio is ∼> 200 Å –1 out to 1 μm, which is sufficient to measure gravity-sensitive features for individual galaxies and to determine how they depend on other properties of the galaxies. Combining the new data with previously obtained spectra for globular clusters in M31 and the most massive elliptical galaxies in the Virgo cluster, we find that the dwarf-sensitive Na I λ8183, 8195 doublet and the FeH λ9916 Wing-Ford band increase systematically with velocity dispersion, while the giant-sensitive Ca II λ8498, 8542, 8662 triplet decreases with dispersion. These trends are consistent with a varying IMF, such that galaxies with deeper potential wells have more dwarf-enriched mass functions. In a companion paper, we use a comprehensive stellar population synthesis model to demonstrate that IMF effects can be separated from age and abundance variations and quantify the IMF variation among early-type galaxies.

  11. SDSS IV MaNGA: the global and local stellar mass assemby histories of galaxies

    Ibarra-Medel, Héctor J.; Sánchez, Sebastián F.; Avila-Reese, Vladimir; Hernández-Toledo, Héctor M.; González, J. Jesús; Drory, Niv; Bundy, Kevin; Bizyaev, Dmitry; Cano-Díaz, Mariana; Malanushenko, Elena; Pan, Kaike; Roman-Lopes, Alexandre; Thomas, Daniel

    2016-12-01

    Using the fossil record method implemented through Pipe3D, we reconstruct the global and radial stellar mass growth histories (MGHs) of a large sample of galaxies, ranging from dwarf to giant objects, from the Mapping Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. We confirm that the main driver of the global MGHs is mass, with more massive galaxies assembling earlier (downsizing), though for a given mass, the global MGHs segregate by colour, specific star formation rate and morphological type. From the inferred radial mean MGHs, we find that at fractions of assembled mass larger than ˜80 per cent, the innermost regions formed stars, on average, in the inside-out mode. At earlier epochs, when the age estimation of the method becomes poor, the MGHs seem to be spatially homogeneous or even in the outside-in mode, especially for the red/quiescent/early-type galaxies. The innermost MGHs are, in general, less scattered around the mean than the outermost MGHs. For dwarf and low-mass galaxies, we do not find evidence of an outside-in formation mode; instead, their radial MGHs are very diverse most of the time, with periods of outside-in and inside-out modes (or strong radial migration), suggesting this is an episodic star formation history. Blue/star-forming/late-type galaxies present, on average, a significantly more pronounced inside-out formation mode than red/quiescent/early-type galaxies, independently of mass. We discuss our results in the light of the processes of galaxy formation, quenching and radial migration. We also discuss the uncertainties and biases of the fossil record method and how these could affect our results.

  12. ORIGIN OF 12 μm EMISSION ACROSS GALAXY POPULATIONS FROM WISE AND SDSS SURVEYS

    Donoso, E.; Yan Lin; Tsai, C.; Eisenhardt, P.; Stern, D.; Assef, R. J.; Leisawitz, D.; Jarrett, T. H.; Stanford, S. A.

    2012-01-01

    We cross-matched Wide-field Infrared Survey Explorer sources brighter than 1 mJy at 12 μm with the Sloan Digital Sky Survey galaxy spectroscopic catalog to produce a sample of ∼10 5 galaxies at (z) = 0.08, the largest of its kind. This sample is dominated (70%) by star-forming (SF) galaxies from the blue sequence, with total IR luminosities in the range ∼10 8 -10 12 L ☉ . We identify which stellar populations are responsible for most of the 12 μm emission. We find that most (∼80%) of the 12 μm emission in SF galaxies is produced by stellar populations younger than 0.6 Gyr. In contrast, the 12 μm emission in weak active galactic nuclei (AGNs; L [Oiii] 7 L . ) is produced by older stars, with ages of ∼1-3 Gyr. We find that L 12μm linearly correlates with stellar mass for SF galaxies. At fixed 12 μm luminosity, weak AGNs deviate toward higher masses since they tend to be hosted by massive, early-type galaxies with older stellar populations. SF galaxies and weak AGNs follow different L 12μm -SFR (star formation rate) relations, with weak AGNs showing excess 12 μm emission at low SFR (0.02-1 M ☉ yr –1 ). This is likely due to dust grains heated by older stars. While the specific star formation rate (SSFR) of SF galaxies is nearly constant, the SSFR of weak AGNs decreases by ∼3 orders of magnitude, reflecting the very different star formation efficiencies between SF galaxies and massive, early-type galaxies. Stronger type II AGNs in our sample (L[ Oiii] > 10 7 L . ), act as an extension of massive SF galaxies, connecting the SF and weak AGN sequences. This suggests a picture where galaxies form stars normally until an AGN (possibly after a starburst episode) starts to gradually quench the SF activity. We also find that 4.6-12 μm color is a useful first-order indicator of SF activity in a galaxy when no other data are available.

  13. THE EFFECT OF HOST GALAXIES ON TYPE Ia SUPERNOVAE IN THE SDSS-II SUPERNOVA SURVEY

    Lampeitl, Hubert; Smith, Mathew; Nichol, Robert C.; Bassett, Bruce; Cinabro, David; Dilday, Benjamin; Jha, Saurabh W.; Foley, Ryan J.; Frieman, Joshua A.; Garnavich, Peter M.; Goobar, Ariel; Nordin, Jakob; Im, Myungshin; Marriner, John; Miquel, Ramon; Oestman, Linda; Riess, Adam G.; Sako, Masao; Schneider, Donald P.; Sollerman, Jesper

    2010-01-01

    We present an analysis of the host galaxy dependences of Type Ia Supernovae (SNe Ia) from the full three year sample of the SDSS-II Supernova Survey. We re-discover, to high significance, the strong correlation between host galaxy type and the width of the observed SN light curve, i.e., fainter, quickly declining SNe Ia favor passive host galaxies, while brighter, slowly declining Ia's favor star-forming galaxies. We also find evidence (at between 2σ and 3σ) that SNe Ia are ≅0.1 ± 0.04 mag brighter in passive host galaxies than in star-forming hosts, after the SN Ia light curves have been standardized using the light-curve shape and color variations. This difference in brightness is present in both the SALT2 and MCLS2k2 light-curve fitting methodologies. We see evidence for differences in the SN Ia color relationship between passive and star-forming host galaxies, e.g., for the MLCS2k2 technique, we see that SNe Ia in passive hosts favor a dust law of R V = 1.0 ± 0.2, while SNe Ia in star-forming hosts require R V = 1.8 +0.2 -0.4 . The significance of these trends depends on the range of SN colors considered. We demonstrate that these effects can be parameterized using the stellar mass of the host galaxy (with a confidence of >4σ) and including this extra parameter provides a better statistical fit to our data. Our results suggest that future cosmological analyses of SN Ia samples should include host galaxy information.

  14. Star formation history of the galaxy merger Mrk848 with SDSS-IV MaNGA

    Yuan, Fang-Ting; Shen, Shiyin; Hao, Lei; Fernandez, Maria Argudo

    2017-03-01

    With the 3D data of SDSS-IV MaNGA (Bundy et al. 2015) spectra and multi-wavelength SED modeling, we expect to have a better understanding of the distribution of dust, gas and star formation of galaxy mergers. For a case study of the merging galaxy Mrk848, we use both UV-to-IR broadband SED and the MaNGA integral field spectroscopy to obtain its star formation histories at the tail and core regions. From the SED fitting and full spectral fitting, we find that the star formation in the tail regions are affected by the interaction earlier than the core regions. The core regions show apparently two times of star formation and a strong burst within 500Myr, indicating the recent star formation is triggered by the interaction. The star formation histories derived from these two methods are basically consistent.

  15. GALAXIES IN FILAMENTS HAVE MORE SATELLITES: THE INFLUENCE OF THE COSMIC WEB ON THE SATELLITE LUMINOSITY FUNCTION IN THE SDSS

    Guo, Quan; Libeskind, N. I. [Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Tempel, E., E-mail: qguo@aip.de [Tartu Observatory, Observatooriumi 1, 61602 Tõravere (Estonia)

    2015-02-20

    We investigate whether the satellite luminosity function (LF) of primary galaxies identified in the Sloan Digital Sky Survey (SDSS) depends on whether the host galaxy is in a filament or not. Isolated primary galaxies are identified in the SDSS spectroscopic sample, and potential satellites (that are up to four magnitudes fainter than their hosts) are searched for in the much deeper photometric sample. Filaments are constructed from the galaxy distribution by the Bisous process. Isolated primary galaxies are divided into two subsamples: those in filaments and those not in filaments. We examine the stacked mean satellite LF of both the filament and nonfilament samples and find that, on average, the satellite LF of galaxies in filaments is significantly higher than those of galaxies not in filaments. The filamentary environment can increase the abundance of the brightest satellites (M {sub sat.} < M {sub prim.} + 2.0) by a factor of ∼2 compared with nonfilament isolated galaxies. This result is independent of the primary galaxy magnitude, although the satellite LF of galaxies in the faintest magnitude bin is too noisy to determine if such a dependence exists. Because our filaments are extracted from a spectroscopic flux-limited sample, we consider the possibility that the difference in satellite LF is due to a redshift, color, or environmental bias, finding these to be insufficient to explain our result. The dependence of the satellite LF on the cosmic web suggests that the filamentary environment may have a strong effect on the efficiency of galaxy formation.

  16. GALAXIES IN FILAMENTS HAVE MORE SATELLITES: THE INFLUENCE OF THE COSMIC WEB ON THE SATELLITE LUMINOSITY FUNCTION IN THE SDSS

    Guo, Quan; Libeskind, N. I.; Tempel, E.

    2015-01-01

    We investigate whether the satellite luminosity function (LF) of primary galaxies identified in the Sloan Digital Sky Survey (SDSS) depends on whether the host galaxy is in a filament or not. Isolated primary galaxies are identified in the SDSS spectroscopic sample, and potential satellites (that are up to four magnitudes fainter than their hosts) are searched for in the much deeper photometric sample. Filaments are constructed from the galaxy distribution by the Bisous process. Isolated primary galaxies are divided into two subsamples: those in filaments and those not in filaments. We examine the stacked mean satellite LF of both the filament and nonfilament samples and find that, on average, the satellite LF of galaxies in filaments is significantly higher than those of galaxies not in filaments. The filamentary environment can increase the abundance of the brightest satellites (M sat. < M prim. + 2.0) by a factor of ∼2 compared with nonfilament isolated galaxies. This result is independent of the primary galaxy magnitude, although the satellite LF of galaxies in the faintest magnitude bin is too noisy to determine if such a dependence exists. Because our filaments are extracted from a spectroscopic flux-limited sample, we consider the possibility that the difference in satellite LF is due to a redshift, color, or environmental bias, finding these to be insufficient to explain our result. The dependence of the satellite LF on the cosmic web suggests that the filamentary environment may have a strong effect on the efficiency of galaxy formation

  17. The population of early-type galaxies: how it evolves with time and how it differs from passive and late-type galaxies

    Tamburri, S.; Saracco, P.; Longhetti, M.; Gargiulo, A.; Lonoce, I.; Ciocca, F.

    2014-10-01

    Aims: There are two aims to our analysis. On the one hand we are interested in addressing whether a sample of morphologically selected early-type galaxies (ETGs) differs from a sample of passive galaxies in terms of galaxy statistics. On the other hand we study how the relative abundance of galaxies, the number density, and, the stellar mass density for different morphological types change over the redshift range 0.6 ≤ z ≤ 2.5. Methods: From the 1302 galaxies brighter than Ks(AB) = 22 selected from the GOODS-MUSIC catalogue, we classified the ETGs, i.e. elliptical (E) and spheroidal galaxies (E/S0), on the basis of their morphology and the passive galaxies on the basis of their specific star formation rate (sSFR ≤ 10-11 yr-1). Since the definition of a passive galaxy depends on the model parameters assumed to fit the spectral energy distribution of the galaxy, in addition to the assumed sSFR threshold, we probed the dependence of this definition and selection on the stellar initial mass function (IMF). Results: We find that spheroidal galaxies cannot be distinguished from the other morphological classes on the basis of their low star formation rate, irrespective of the IMF adopted in the models. In particular, we find that a large fraction of passive galaxies (>30%) are disc-shaped objects and that the passive selection misses a significant fraction (~26%) of morphologically classified ETGs. Using the sample of 1302 galaxies morphologically classified into spheroidal galaxies (ETGs) and non-spheroidal galaxies (LTGs), we find that the fraction of these two morphological classes is constant over the redshift range 0.6 ≤ z ≤ 2.5, being 20-30% the fraction of ETGs and 70-80% the fraction of LTGs. However, at z mass density of the whole population of massive galaxies increase by almost a factor of ~10 between 0.6 ≤ z ≤ 2.5, with a faster increase of these densities for the ETGs than for the LTGs. Finally, we find that the number density of the highest

  18. THE DATA REDUCTION PIPELINE FOR THE SDSS-IV MaNGA IFU GALAXY SURVEY

    Law, David R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Cherinka, Brian [Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Yan, Renbin [Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055 (United States); Andrews, Brett H. [Department of Physics and Astronomy and PITT PACC, University of Pittsburgh, 3941 O’Hara Street, Pittsburgh, PA 15260 (United States); Bershady, Matthew A. [Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706 (United States); Bizyaev, Dmitry [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Blanc, Guillermo A. [Departamento de Astronomía, Universidad de Chile, Camino del Observatorio 1515, Las Condes, Santiago (Chile); Blanton, Michael R. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Bolton, Adam S.; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Salt Lake City, UT 84112 (United States); Bundy, Kevin [Kavli Institute for the Physics and Mathematics of the universe, Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa, 277-8583 (Kavli IPMU, WPI) (Japan); Chen, Yanmei [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Drory, Niv [McDonald Observatory, Department of Astronomy, University of Texas at Austin, 1 University Station, Austin, TX 78712-0259 (United States); D’Souza, Richard; Jones, Amy; Kauffmann, Guinevere [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Fu, Hai, E-mail: dlaw@stsci.edu [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); and others

    2016-10-01

    Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622–10354 Å and an average footprint of ∼500 arcsec{sup 2} per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low-redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ∼100 million raw-frame spectra and ∼10 million reduced galaxy spectra over the six-year lifetime of the survey. In this contribution, we describe the MaNGA Data Reduction Pipeline algorithms and centralized metadata framework that produce sky-subtracted spectrophotometrically calibrated spectra and rectified three-dimensional data cubes that combine individual dithered observations. For the 1390 galaxy data cubes released in Summer 2016 as part of SDSS-IV Data Release 13, we demonstrate that the MaNGA data have nearly Poisson-limited sky subtraction shortward of ∼8500 Å and reach a typical 10 σ limiting continuum surface brightness μ  = 23.5 AB arcsec{sup −2} in a five-arcsecond-diameter aperture in the g -band. The wavelength calibration of the MaNGA data is accurate to 5 km s{sup −1} rms, with a median spatial resolution of 2.54 arcsec FWHM (1.8 kpc at the median redshift of 0.037) and a median spectral resolution of σ  = 72 km s{sup −1}.

  19. The Data Reduction Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey

    Law, David R.; Cherinka, Brian; Yan, Renbin; Andrews, Brett H.; Bershady, Matthew A.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Bolton, Adam S.; Brownstein, Joel R.; Bundy, Kevin; Chen, Yanmei; Drory, Niv; D'Souza, Richard; Fu, Hai; Jones, Amy; Kauffmann, Guinevere; MacDonald, Nicholas; Masters, Karen L.; Newman, Jeffrey A.; Parejko, John K.; Sánchez-Gallego, José R.; Sánchez, Sebastian F.; Schlegel, David J.; Thomas, Daniel; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.; Zhang, Kai

    2016-10-01

    Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622-10354 Å and an average footprint of ˜500 arcsec2 per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low-redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ˜100 million raw-frame spectra and ˜10 million reduced galaxy spectra over the six-year lifetime of the survey. In this contribution, we describe the MaNGA Data Reduction Pipeline algorithms and centralized metadata framework that produce sky-subtracted spectrophotometrically calibrated spectra and rectified three-dimensional data cubes that combine individual dithered observations. For the 1390 galaxy data cubes released in Summer 2016 as part of SDSS-IV Data Release 13, we demonstrate that the MaNGA data have nearly Poisson-limited sky subtraction shortward of ˜8500 Å and reach a typical 10σ limiting continuum surface brightness μ = 23.5 AB arcsec-2 in a five-arcsecond-diameter aperture in the g-band. The wavelength calibration of the MaNGA data is accurate to 5 km s-1 rms, with a median spatial resolution of 2.54 arcsec FWHM (1.8 kpc at the median redshift of 0.037) and a median spectral resolution of σ = 72 km s-1.

  20. THE DATA REDUCTION PIPELINE FOR THE SDSS-IV MaNGA IFU GALAXY SURVEY

    Law, David R.; Cherinka, Brian; Yan, Renbin; Andrews, Brett H.; Bershady, Matthew A.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Bolton, Adam S.; Brownstein, Joel R.; Bundy, Kevin; Chen, Yanmei; Drory, Niv; D’Souza, Richard; Jones, Amy; Kauffmann, Guinevere; Fu, Hai

    2016-01-01

    Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622–10354 Å and an average footprint of ∼500 arcsec 2 per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low-redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ∼100 million raw-frame spectra and ∼10 million reduced galaxy spectra over the six-year lifetime of the survey. In this contribution, we describe the MaNGA Data Reduction Pipeline algorithms and centralized metadata framework that produce sky-subtracted spectrophotometrically calibrated spectra and rectified three-dimensional data cubes that combine individual dithered observations. For the 1390 galaxy data cubes released in Summer 2016 as part of SDSS-IV Data Release 13, we demonstrate that the MaNGA data have nearly Poisson-limited sky subtraction shortward of ∼8500 Å and reach a typical 10 σ limiting continuum surface brightness μ  = 23.5 AB arcsec −2 in a five-arcsecond-diameter aperture in the g -band. The wavelength calibration of the MaNGA data is accurate to 5 km s −1 rms, with a median spatial resolution of 2.54 arcsec FWHM (1.8 kpc at the median redshift of 0.037) and a median spectral resolution of σ  = 72 km s −1 .

  1. Spectral Analysis, Synthesis, & Energy Distributions of Nearby E+A Galaxies Using SDSS-IV MaNGA

    Weaver, Olivia A.; Anderson, Miguel Ricardo; Wally, Muhammad; James, Olivia; Falcone, Julia; Liu, Allen; Wallack, Nicole; Liu, Charles; SDSS Collaboration

    2017-01-01

    Utilizing data from the Mapping Nearby Galaxies at APO (MaNGA) Survey (MaNGA Product Launch-4, or MPL-4), of the latest generation of the Sloan Digital Sky Survey (SDSS-IV), we identified nine post-starburst (E+A) systems that lie within the Green Valley transition zone. We identify the E+A galaxies by their SDSS single fiber spectrum and u-r color, then confirmed their classification as post-starburst by coding/plotting methods and spectral synthesis codes (FIREFLY and PIPE3D), as well as with their Spectral Energy Distributions (SEDs) from 0.15 µm to 22 µm, using GALEX, SDSS, 2MASS, and WISE data. We produced maps of gaussian-fitted fluxes, equivalent widths, stellar velocities, metallicities and age. We also produced spectral line ratio diagrams to classify regions of stellar populations of the galaxies. We found that our sample of E+As retain their post-starburst properties across the entire galaxy, not just at their center. We detected matching a trend line in the ultraviolet and optical bands, consistent with the expected SEDs for an E+A galaxy, and also through the J, H and Ks bands, except for one object. We classified one of the nine galaxies as a luminous infrared galaxy, unusual for a post-starburst object. Our group seeks to further study stellar population properties, spectral energy distributions and quenching properties in E+A galaxies, and investigate their role in galaxy evolution as a whole. This work was supported by the Alfred P. Sloan Foundation via the SDSS-IV Faculty and Student Team (FAST) initiative, ARC Agreement #SSP483 to the CUNY College of Staten Island. This work was also supported by grants to The American Museum of Natural History, and the CUNY College of Staten Island through from National Science Foundation.

  2. Eight luminous early-type galaxies in nearby pairs and sparse groups. I. Stellar populations spatially analysed

    Rosa, D. A.; Milone, A. C.; Krabbe, A. C.; Rodrigues, I.

    2018-06-01

    We present a detailed spatial analysis of stellar populations based on long-slit optical spectra in a sample of eight luminous early-type galaxies selected from nearby sparse groups and pairs, three of them may have interaction with another galaxy of similar mass. We have spatially measured luminosity-weighted averages of age, [M/H], [Fe/H], and [α /Fe] in the sample galaxies to add empirical data relative to the influence of galaxy mass, environment, interaction, and AGN feedback in their formation and evolution. The stellar population of the individual galaxies were determined through the well-established stellar population synthesis code starlight using semi-empirical simple stellar population models. Radial variations of luminosity- weighted means of age, [M/H], [Fe/H], and [α /Fe] were quantified up to half of the effective radius of each galaxy. We found trends between representative values of age, [M/H], [α /Fe], and the nuclear stellar velocity dispersion. There are also relations between the metallicity/age gradients and the velocity dispersion. Contributions of 1-4 Gyr old stellar populations were quantified in IC 5328 and NGC 6758 as well as 4-8 Gyr old ones in NGC 5812. Extended gas is present in IC 5328, NGC 1052, NGC 1209, and NGC 6758, and the presence of a LINER is identified in all these galaxies. The regions up to one effective radius of all galaxies are basically dominated by α -enhanced metal-rich old stellar populations likely due to rapid star formation episodes that induced efficient chemical enrichment. On average, the age and [α /Fe] gradients are null and the [M/H] gradients are negative, although discordant cases were found. We found no correlation between the stellar population properties and the LINER presence as well as between the stellar properties and environment or gravitational interaction, suggesting that the influence of progenitor mass cannot be discarded in the formation and evolution of early-type galaxies.

  3. Central Structural Parameters of Early-Type Galaxies as Viewed with Nicmos on the Hubble Space Telescope

    Ravindranath, Swara; Ho, Luis C.; Peng, Chien Y.; Filippenko, Alexei V.; Sargent, Wallace L. W.

    2001-08-01

    We present surface photometry for the central regions of a sample of 33 early-type (E, S0, and S0/a) galaxies observed at 1.6 μm (H band) using the Hubble Space Telescope. Dust absorption has less of an impact on the galaxy morphologies in the near-infrared than found in previous work based on observations at optical wavelengths. When present, dust seems to be most commonly associated with optical line emission. We employ a new technique of two-dimensional fitting to extract quantitative parameters for the bulge light distribution and nuclear point sources, taking into consideration the effects of the point-spread function. By parameterizing the bulge profile with a Nuker law, we confirm that the central surface brightness distributions largely fall into two categories, each of which correlates with the global properties of the galaxies. ``Core'' galaxies tend to be luminous elliptical galaxies with boxy or pure elliptical isophotes, whereas ``power-law'' galaxies are preferentially lower luminosity systems with disky isophotes. The infrared surface brightness profiles are very similar to those in the optical, with notable exceptions being very dusty objects. Similar to the study of Faber et al., based on optical data, we find that galaxy cores obey a set of fundamental plane relations wherein more luminous galaxies with higher central stellar velocity dispersions generally possess larger cores with lower surface brightnesses. Unlike most previous studies, however, we do not find a clear gap in the distribution of inner cusp slopes; several objects have inner cusp slopes (0.3law galaxies. The nature of these intermediate objects is unclear. We draw attention to two objects in the sample that appear to be promising cases of galaxies with isothermal cores that are not the brightest members of a cluster. Unresolved nuclear point sources are found in ~50% of the sample galaxies, roughly independent of profile type, with magnitudes in the range mnucH=12.8 to 17.4 mag

  4. Galaxy clusters in the SDSS Stripe 82 based on photometric redshifts

    Durret, F.; Adami, C.; Bertin, E.; Hao, J.; Márquez, I.

    2015-01-01

    Based on a recent photometric redshift galaxy catalogue, we have searched for galaxy clusters in the Stripe ~82 region of the Sloan Digital Sky Survey by applying the Adami & MAzure Cluster FInder (AMACFI). Extensive tests were made to fine-tune the AMACFI parameters and make the cluster detection as reliable as possible. The same method was applied to the Millennium simulation to estimate our detection efficiency and the approximate masses of the detected clusters. Considering all the cluster galaxies (i.e. within a 1 Mpc radius of the cluster to which they belong and with a photoz differing by less than 0.05 from that of the cluster), we stacked clusters in various redshift bins to derive colour-magnitude diagrams and galaxy luminosity functions (GLFs). For each galaxy with absolute magnitude brighter than -19.0 in the r band, we computed the disk and spheroid components by applying SExtractor, and by stacking clusters we determined how the disk-to-spheroid flux ratio varies with cluster redshift and mass. We also detected 3663 clusters in the redshift range 0.15< z<0.70, with estimated mean masses between 10"1"3 and a few 10"1"4 solar masses. Furthermore, by stacking the cluster galaxies in various redshift bins, we find a clear red sequence in the (g'-r') versus r' colour-magnitude diagrams, and the GLFs are typical of clusters, though with a possible contamination from field galaxies. The morphological analysis of the cluster galaxies shows that the fraction of late-type to early-type galaxies shows an increase with redshift (particularly in high mass clusters) and a decrease with detection level, i.e. cluster mass. From the properties of the cluster galaxies, the majority of the candidate clusters detected here seem to be real clusters with typical cluster properties.

  5. Overview of the SDSS-IV MaNGA Survey: Mapping nearby Galaxies at Apache Point Observatory

    Bundy, Kevin; Bershady, Matthew A.; Law, David R.; Yan, Renbin; Drory, Niv; MacDonald, Nicholas; Wake, David A.; Cherinka, Brian; Sánchez-Gallego, José R.; Weijmans, Anne-Marie; Thomas, Daniel; Tremonti, Christy; Masters, Karen; Coccato, Lodovico; Diamond-Stanic, Aleksandar M.; Aragón-Salamanca, Alfonso; Avila-Reese, Vladimir; Badenes, Carles; Falcón-Barroso, Jésus; Belfiore, Francesco; Bizyaev, Dmitry; Blanc, Guillermo A.; Bland-Hawthorn, Joss; Blanton, Michael R.; Brownstein, Joel R.; Byler, Nell; Cappellari, Michele; Conroy, Charlie; Dutton, Aaron A.; Emsellem, Eric; Etherington, James; Frinchaboy, Peter M.; Fu, Hai; Gunn, James E.; Harding, Paul; Johnston, Evelyn J.; Kauffmann, Guinevere; Kinemuchi, Karen; Klaene, Mark A.; Knapen, Johan H.; Leauthaud, Alexie; Li, Cheng; Lin, Lihwai; Maiolino, Roberto; Malanushenko, Viktor; Malanushenko, Elena; Mao, Shude; Maraston, Claudia; McDermid, Richard M.; Merrifield, Michael R.; Nichol, Robert C.; Oravetz, Daniel; Pan, Kaike; Parejko, John K.; Sanchez, Sebastian F.; Schlegel, David; Simmons, Audrey; Steele, Oliver; Steinmetz, Matthias; Thanjavur, Karun; Thompson, Benjamin A.; Tinker, Jeremy L.; van den Bosch, Remco C. E.; Westfall, Kyle B.; Wilkinson, David; Wright, Shelley; Xiao, Ting; Zhang, Kai

    We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. MaNGA will investigate the internal kinematic

  6. THE SL2S GALAXY-SCALE LENS SAMPLE. V. DARK MATTER HALOS AND STELLAR IMF OF MASSIVE EARLY-TYPE GALAXIES OUT TO REDSHIFT 0.8

    Sonnenfeld, Alessandro; Treu, Tommaso [Physics Department, University of California, Santa Barbara, CA 93106 (United States); Marshall, Philip J. [Kavli Institute for Particle Astrophysics and Cosmology, P.O. Box 20450, MS29, Stanford, CA 94309 (United States); Suyu, Sherry H. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Gavazzi, Raphaël [Institut d' Astrophysique de Paris, UMR7095 CNRS-Université Pierre et Marie Curie, 98bis bd Arago, F-75014 Paris (France); Auger, Matthew W. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Nipoti, Carlo, E-mail: sonnen@physics.ucsb.edu [Department of Physics and Astronomy, Bologna University, viale Berti-Pichat 6/2, I-40127 Bologna (Italy)

    2015-02-20

    We investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference method to measure the distribution of dark matter mass and stellar initial mass function (IMF) across the population of massive early-type galaxies. Lensing selection effects are taken into account. We find that the dark matter mass projected within the inner 5 kpc increases for increasing redshift, decreases for increasing stellar mass density, but is roughly constant along the evolutionary tracks of early-type galaxies. The average dark matter slope is consistent with that of a Navarro-Frenk-White profile, but is not well constrained. The stellar IMF normalization is close to a Salpeter IMF at log M {sub *} = 11.5 and scales strongly with increasing stellar mass. No dependence of the IMF on redshift or stellar mass density is detected. The anti-correlation between dark matter mass and stellar mass density supports the idea of mergers being more frequent in more massive dark matter halos.

  7. A multi-wavelength study of the evolution of early-type galaxies in groups: the ultraviolet view

    Rampazzo, R.; Mazzei, P.; Marino, A.; Bianchi, L.; Plana, H.; Trinchieri, G.; Uslenghi, M.; Wolter, A.

    2018-04-01

    The ultraviolet-optical colour magnitude diagram of rich galaxy groups is characterised by a well developed Red Sequence, a Blue Cloud and the so-called Green Valley. Loose, less evolved groups of galaxies which are probably not virialised yet may lack a well defined Red Sequence. This is actually explained in the framework of galaxy evolution. We are focussing on understanding galaxy migration towards the Red Sequence, checking for signatures of such a transition in their photometric and morphological properties. We report on the ultraviolet properties of a sample of early-type (ellipticals+S0s) galaxies inhabiting the Red Sequence. The analysis of their structures, as derived by fitting a Sérsic law to their ultraviolet luminosity profiles, suggests the presence of an underlying disk. This is the hallmark of dissipation processes that still must have a role to play in the evolution of this class of galaxies. Smooth particle hydrodynamic simulations with chemo-photometric implementations able to match the global properties of our targets are used to derive their evolutionary paths through ultraviolet-optical colour magnitude diagrams, providing some fundamental information such as the crossing time through the Green Valley, which depends on their luminosity. The transition from the Blue Cloud to the Red Sequence takes several Gyrs, being about 3-5 Gyr for the brightest galaxies and longer for fainter ones, if occurring. The photometric study of nearby galaxy structures in the ultraviolet is seriously hampered by either the limited field of view of the cameras (e.g., in Hubble Space Telescope) or by the low spatial resolution of the images (e.g., in the Galaxy Evolution Explorer). Current missions equipped with telescopes and cameras sensitive to ultraviolet wavelengths, such as Swift- UVOT and Astrosat-UVIT, provide a relatively large field of view and a better resolution than the Galaxy Evolution Explorer. More powerful ultraviolet instruments (size, resolution

  8. ACOUSTIC SCALE FROM THE ANGULAR POWER SPECTRA OF SDSS-III DR8 PHOTOMETRIC LUMINOUS GALAXIES

    Seo, Hee-Jong [Berkeley Center for Cosmological Physics, LBL and Department of Physics, University of California, Berkeley, CA 94720 (United States); Ho, Shirley; White, Martin; Reid, Beth; Schlegel, David J. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Cuesta, Antonio J.; Padmanabhan, Nikhil [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States); Ross, Ashley J.; Percival, Will J.; Nichol, Robert C. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Saito, Shun [Department of Astronomy, 601 Campbell Hall, University of California at Berkeley, Berkeley, CA 94720 (United States); De Putter, Roland [Instituto de Fisica Corpuscular, Valencia (Spain); Eisenstein, Daniel J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Xu Xiaoying; Skibba, Ramin [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Schneider, Donald P. [Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802 (United States); Verde, Licia [Institucio Catalana de Recerca i Estudis Avancats, Barcelona (Spain); Bizyaev, Dmitry; Brewington, Howard; Brinkmann, J. [Apache Point Observatory, 2001 Apache Point Road, Sunspot, NM 88349 (United States); and others

    2012-12-10

    We measure the acoustic scale from the angular power spectra of the Sloan Digital Sky Survey III (SDSS-III) Data Release 8 imaging catalog that includes 872, 921 galaxies over {approx}10,000 deg{sup 2} between 0.45 < z < 0.65. The extensive spectroscopic training set of the Baryon Oscillation Spectroscopic Survey luminous galaxies allows precise estimates of the true redshift distributions of galaxies in our imaging catalog. Utilizing the redshift distribution information, we build templates and fit to the power spectra of the data, which are measured in our companion paper, to derive the location of Baryon acoustic oscillations (BAOs) while marginalizing over many free parameters to exclude nearly all of the non-BAO signal. We derive the ratio of the angular diameter distance to the sound horizon scale D{sub A} (z)/r{sub s} = 9.212{sup +0.416}{sub -{sub 0.404}} at z = 0.54, and therefore D{sub A} (z) = 1411 {+-} 65 Mpc at z = 0.54; the result is fairly independent of assumptions on the underlying cosmology. Our measurement of angular diameter distance D{sub A} (z) is 1.4{sigma} higher than what is expected for the concordance {Lambda}CDM, in accordance to the trend of other spectroscopic BAO measurements for z {approx}> 0.35. We report constraints on cosmological parameters from our measurement in combination with the WMAP7 data and the previous spectroscopic BAO measurements of SDSS and WiggleZ. We refer to our companion papers (Ho et al.; de Putter et al.) for investigations on information of the full power spectrum.

  9. Infrared photometry of the nuclei of early-type radio galaxies

    Sparks, W.B.; Bailey, J.

    1986-01-01

    J,H,K,L' two-aperture photometry and single-aperture 10-μm(N) photometry of the nuclei of 44 nearby radio elliptical and SO galaxies are presented. Clear infrared excesses are found from the galaxies with broad emission-lines, the BL Lac objects, and two other galaxies, one of which appears to have an extended infrared excess. In addition, the sample as a whole appears to have positive 10-μm emission which is believed to be largely due to starlight. The near-infrared colours in general are characteristic of normal starlight, with only the strongest 10-μm emitters showing a significant near-infrared excess. These latter galaxies have blue optical colours. (author)

  10. A multiparametric analysis of the Einstein sample of early-type galaxies. 1: Luminosity and ISM parameters

    Eskridge, Paul B.; Fabbiano, Giuseppina; Kim, Dong-Woo

    1995-01-01

    We have conducted bivariate and multivariate statistical analysis of data measuring the luminosity and interstellar medium of the Einstein sample of early-type galaxies (presented by Fabbiano, Kim, & Trinchieri 1992). We find a strong nonlinear correlation between L(sub B) and L(sub X), with a power-law slope of 1.8 +/- 0.1, steepening to 2.0 +/- if we do not consider the Local Group dwarf galaxies M32 and NGC 205. Considering only galaxies with log L(sub X) less than or equal to 40.5, we instead find a slope of 1.0 +/- 0.2 (with or without the Local Group dwarfs). Although E and S0 galaxies have consistent slopes for their L(sub B)-L(sub X) relationships, the mean values of the distribution functions of both L(sub X) and L(sub X)/L(sub B) for the S0 galaxies are lower than those for the E galaxies at the 2.8 sigma and 3.5 sigma levels, respectively. We find clear evidence for a correlation between L(sub X) and the X-ray color C(sub 21), defined by Kim, Fabbiano, & Trinchieri (1992b), which indicates that X-ray luminosity is correlated with the spectral shape below 1 keV in the sense that low-L(sub X) systems have relatively large contributions from a soft component compared with high-L(sub X) systems. We find evidence from our analysis of the 12 micron IRAS data for our sample that our S0 sample has excess 12 micron emission compared with the E sample, scaled by their optical luminosities. This may be due to emission from dust heated in star-forming regions in S0 disks. This interpretation is reinforced by the existence of a strong L(sub 12)-L(sub 100) correlation for our S0 sample that is not found for the E galaxies, and by an analysis of optical-IR colors. We find steep slopes for power-law relationships between radio luminosity and optical, X-ray, and far-IR (FIR) properties. This last point argues that the presence of an FIR-emitting interstellar medium (ISM) in early-type galaxies is coupled to their ability to generate nonthermal radio continuum, as

  11. TWO LENSED z ≅ 3 LYMAN BREAK GALAXIES DISCOVERED IN THE SDSS GIANT ARCS SURVEY

    Koester, Benjamin P.; Gladders, Michael D.; Sharon, Keren; Wuyts, Eva; Bayliss, Matthew B.; Hennawi, Joseph F.; Rigby, J. R.; Dahle, Hakon

    2010-01-01

    We report the discovery of two strongly lensed z ∼ 3 Lyman break galaxies (LBGs) discovered as u-band dropouts as part of the SDSS Giant Arcs Survey (SGAS). The first, SGAS J122651.3+215220 at z = 2.9233, is lensed by one of several sub-clusters, SDSS J1226+2152, in a complex massive cluster at z = 0.43. Its (g, r, i) magnitudes are (21.14, 20.60, 20.51) which translate to surface brightnesses, μ g,r,i , of (23.78, 23.11, 22.81). The second, SGAS J152745.1+065219, is an LBG at z = 2.7593 lensed by the foreground SDSS J1527+0652 at z = 0.39, with (g, r, z) = (20.90, 20.52, 20.58) and μ g,r,z = (25.15, 24.52, 24.12). Moderate resolution spectroscopy confirms the redshifts suggested by photometric breaks and shows both absorption and emission features typical of LBGs. Lens mass models derived from combined imaging and spectroscopy reveal that SGAS J122651.3+215220 is a highly magnified source (M ≅ 40), while SGAS J152745.1+065219 is magnified by no more than M ≅ 15. Compared with LBG survey results, the luminosities and lensing-corrected magnitudes suggest that SGAS J122651.3+215220 is among the faintest ≅20% of LBGs in that sample. SGAS J152745.1+065219, on the other hand, has an unlensed r-band apparent magnitude similar to that of the 'Cosmic Eye', which places it near the mean of LBG survey results over similar redshifts.

  12. ON THE AVERAGE DENSITY PROFILE OF DARK-MATTER HALOS IN THE INNER REGIONS OF MASSIVE EARLY-TYPE GALAXIES

    Grillo, C.

    2012-01-01

    We study a sample of 39 massive early-type lens galaxies at redshift z ∼< 0.3 to determine the slope of the average dark-matter density profile in the innermost regions. We keep the strong-lensing and stellar population synthesis modeling as simple as possible to measure the galaxy total and luminous masses. By rescaling the values of the Einstein radius and dark-matter projected mass with the values of the luminous effective radius and mass, we combine all the data of the galaxies in the sample. We find that between 0.3 and 0.9 times the value of the effective radius the average logarithmic slope of the dark-matter projected density profile is –1.0 ± 0.2 (i.e., approximately isothermal) or –0.7 ± 0.5 (i.e., shallower than isothermal), if, respectively, a constant Chabrier or heavier, Salpeter-like stellar initial mass function is adopted. These results provide positive evidence of the influence of the baryonic component on the contraction of the galaxy dark-matter halos, compared to the predictions of dark-matter-only cosmological simulations, and open a new way to test models of structure formation and evolution within the standard ΛCDM cosmological scenario.

  13. An ALMA view of star formation efficiency suppression in early-type galaxies after gas-rich minor mergers

    van de Voort, Freeke; Davis, Timothy A.; Matsushita, Satoki; Rowlands, Kate; Shabala, Stanislav S.; Allison, James R.; Ting, Yuan-Sen; Sansom, Anne E.; van der Werf, Paul P.

    2018-05-01

    Gas-rich minor mergers contribute significantly to the gas reservoir of early-type galaxies (ETGs) at low redshift, yet the star formation efficiency (SFE; the star formation rate divided by the molecular gas mass) appears to be strongly suppressed following some of these events, in contrast to the more well-known merger-driven starbursts. We present observations with the Atacama Large Millimeter/submillimeter Array (ALMA) of six ETGs, which have each recently undergone a gas-rich minor merger, as evidenced by their disturbed stellar morphologies. These galaxies were selected because they exhibit extremely low SFEs. We use the resolving power of ALMA to study the morphology and kinematics of the molecular gas. The majority of our galaxies exhibit spatial and kinematical irregularities, such as detached gas clouds, warps, and other asymmetries. These asymmetries support the interpretation that the suppression of the SFE is caused by dynamical effects stabilizing the gas against gravitational collapse. Through kinematic modelling we derive high velocity dispersions and Toomre Q stability parameters for the gas, but caution that such measurements in edge-on galaxies suffer from degeneracies. We estimate merger ages to be about 100 Myr based on the observed disturbances in the gas distribution. Furthermore, we determine that these galaxies lie, on average, two orders of magnitude below the Kennicutt-Schmidt relation for star-forming galaxies as well as below the relation for relaxed ETGs. We discuss potential dynamical processes responsible for this strong suppression of star formation surface density at fixed molecular gas surface density.

  14. Large Binocular Telescope/LUCIFER spectroscopy: kinematics of a compact early-type galaxy at z ≃ 1.4

    Longhetti, M.; Saracco, P.; Gargiulo, A.; Tamburri, S.; Lonoce, I.

    2014-04-01

    We present a high signal-to-noise ratio (S/N > 10) medium-resolution (R = 2000) Large Binocular Telescope/LUCIFER spectrum of the early-type galaxy (ETG) S2F1-142 at z ≃ 1.4. By means of the CaT line at 8662 Å, we measured its redshift z = 1.386 ± 0.001 and we estimated its velocity dispersion σ v=340^{-60}_{+120} km s-1. Its corresponding virial mass is 3.9 × 1011 M⊙, compatible with the stellar mass estimates obtained assuming initial mass functions (IMFs) less dwarf rich than the Salpeter one. S2F1-142 is a compact galaxy with Re = 3.1 ± 0.2 kpc, i.e. an effective radius more than three times smaller than the average Re of ETGs with the same mass in the local Universe. At the same time, we found local and high-redshift galaxies with a similar mass content and similar effective radius confirming that it is fully consistent with the already available measures of Re and σv both in the local and in the distant Universe. Considering the distribution of Re and σv as a function of the stellar mass content of ETGs, both in the local and in the distant Universe, we noticed that the measured velocity dispersions of the more compact galaxies are on average slightly lower than expected on the basis of their compactness and the virial theorem, suggesting that (i) their dark matter content is lower than in the more diffuse galaxies and/or (ii) their luminosity profiles are steeper than in the more diffuse galaxies and/or (iii) their larger compactness is an apparent effect caused by the overestimate of their stellar mass content (due to bottom lighter IMF and/or systematic affecting the stellar mass estimates).

  15. Identification of old tidal dwarfs near early-type galaxies from deep imaging and H I observations

    Duc, Pierre-Alain; Paudel, Sanjaya; McDermid, Richard M.; Cuillandre, Jean-Charles; Serra, Paolo; Bournaud, Frédéric; Cappellari, Michele; Emsellem, Eric

    2014-05-01

    It has recently been proposed that the dwarf spheroidal galaxies located in the Local Group discs of satellites (DoSs) may be tidal dwarf galaxies (TDGs) born in a major merger at least 5 Gyr ago. Whether TDGs can live that long is still poorly constrained by observations. As part of deep optical and H I surveys with the Canada-France-Hawaii Telescope (CFHT) MegaCam camera and Westerbork Synthesis Radio Telescope made within the ATLAS3D project, and follow-up spectroscopic observations with the Gemini-North telescope, we have discovered old TDG candidates around several early-type galaxies. At least one of them has an oxygen abundance close to solar, as expected for a tidal origin. This confirmed pre-enriched object is located within the gigantic, but very low surface brightness, tidal tail that emanates from the elliptical galaxy, NGC 5557. An age of 4 Gyr estimated from its SED fitting makes it the oldest securely identified TDG ever found so far. We investigated the structural and gaseous properties of the TDG and of a companion located in the same collisional debris, and thus most likely of tidal origin as well. Despite several Gyr of evolution close to their parent galaxies, they kept a large gas reservoir. Their central surface brightness is low and their effective radius much larger than that of typical dwarf galaxies of the same mass. This possibly provides us with criteria to identify tidal objects which can be more easily checked than the traditional ones requiring deep spectroscopic observations. In view of the above, we discuss the survival time of TDGs and question the tidal origin of the DoSs.

  16. EARLY-TYPE GALAXIES AT z ∼ 1.3. II. MASSES AND AGES OF EARLY-TYPE GALAXIES IN DIFFERENT ENVIRONMENTS AND THEIR DEPENDENCE ON STELLAR POPULATION MODEL ASSUMPTIONS

    Raichoor, A.; Mei, S.; Huertas-Company, M.; Nakata, F.; Kodama, T.; Stanford, S. A.; Rettura, A.; Jee, M. J.; Holden, B. P.; Illingworth, G.; Postman, M.; White, R. L.; Rosati, P.; Blakeslee, J. P.; Demarco, R.; Eisenhardt, P.; Tanaka, M.

    2011-01-01

    We have derived masses and ages for 79 early-type galaxies (ETGs) in different environments at z ∼ 1.3 in the Lynx supercluster and in the GOODS/CDF-S field using multi-wavelength (0.6-4.5 μm; KPNO, Palomar, Keck, Hubble Space Telescope, Spitzer) data sets. At this redshift the contribution of the thermally pulsing asymptotic giant branch (TP-AGB) phase is important for ETGs, and the mass and age estimates depend on the choice of the stellar population model used in the spectral energy distribution fits. We describe in detail the differences among model predictions for a large range of galaxy ages, showing the dependence of these differences on age. Current models still yield large uncertainties. While recent models from Maraston and Charlot and Bruzual offer better modeling of the TP-AGB phase with respect to less recent Bruzual and Charlot models, their predictions do not often match. The modeling of this TP-AGB phase has a significant impact on the derived parameters for galaxies observed at high redshift. Some of our results do not depend on the choice of the model: for all models, the most massive galaxies are the oldest ones, independent of the environment. When using the Maraston and Charlot and Bruzual models, the mass distribution is similar in the clusters and in the groups, whereas in our field sample there is a deficit of massive (M ∼> 10 11 M sun ) ETGs. According to those last models, ETGs belonging to the cluster environment host on average older stars with respect to group and field populations. This difference is less significant than the age difference in galaxies of different masses.

  17. ACOUSTIC SCALE FROM THE ANGULAR POWER SPECTRA OF SDSS-III DR8 PHOTOMETRIC LUMINOUS GALAXIES

    Seo, Hee-Jong; Ho, Shirley; White, Martin; Reid, Beth; Schlegel, David J.; Cuesta, Antonio J.; Padmanabhan, Nikhil; Ross, Ashley J.; Percival, Will J.; Nichol, Robert C.; Saito, Shun; De Putter, Roland; Eisenstein, Daniel J.; Xu Xiaoying; Skibba, Ramin; Schneider, Donald P.; Verde, Licia; Bizyaev, Dmitry; Brewington, Howard; Brinkmann, J.

    2012-01-01

    We measure the acoustic scale from the angular power spectra of the Sloan Digital Sky Survey III (SDSS-III) Data Release 8 imaging catalog that includes 872, 921 galaxies over ∼10,000 deg 2 between 0.45 A (z)/r s = 9.212 +0.416 – 0 .404 at z = 0.54, and therefore D A (z) = 1411 ± 65 Mpc at z = 0.54; the result is fairly independent of assumptions on the underlying cosmology. Our measurement of angular diameter distance D A (z) is 1.4σ higher than what is expected for the concordance ΛCDM, in accordance to the trend of other spectroscopic BAO measurements for z ∼> 0.35. We report constraints on cosmological parameters from our measurement in combination with the WMAP7 data and the previous spectroscopic BAO measurements of SDSS and WiggleZ. We refer to our companion papers (Ho et al.; de Putter et al.) for investigations on information of the full power spectrum.

  18. THE ACS FORNAX CLUSTER SURVEY. X. COLOR GRADIENTS OF GLOBULAR CLUSTER SYSTEMS IN EARLY-TYPE GALAXIES

    Liu Chengze; Peng, Eric W.; Jordan, Andres; Ferrarese, Laura; Blakeslee, John P.; Cote, Patrick; Mei, Simona

    2011-01-01

    We use the largest homogeneous sample of globular clusters (GCs), drawn from the ACS Virgo Cluster Survey (ACSVCS) and ACS Fornax Cluster Survey (ACSFCS), to investigate the color gradients of GC systems in 76 early-type galaxies. We find that most GC systems possess an obvious negative gradient in (g-z) color with radius (bluer outward), which is consistent with previous work. For GC systems displaying color bimodality, both metal-rich and metal-poor GC subpopulations present shallower but significant color gradients on average, and the mean color gradients of these two subpopulations are of roughly equal strength. The field of view of ACS mainly restricts us to measuring the inner gradients of the studied GC systems. These gradients, however, can introduce an aperture bias when measuring the mean colors of GC subpopulations from relatively narrow central pointings. Inferred corrections to previous work imply a reduced significance for the relation between the mean color of metal-poor GCs and their host galaxy luminosity. The GC color gradients also show a dependence with host galaxy mass where the gradients are weakest at the ends of the mass spectrum-in massive galaxies and dwarf galaxies-and strongest in galaxies of intermediate mass, around a stellar mass of M * ∼10 10 M sun . We also measure color gradients for field stars in the host galaxies. We find that GC color gradients are systematically steeper than field star color gradients, but the shape of the gradient-mass relation is the same for both. If gradients are caused by rapid dissipational collapse and weakened by merging, these color gradients support a picture where the inner GC systems of most intermediate-mass and massive galaxies formed early and rapidly with the most massive galaxies having experienced greater merging. The lack of strong gradients in the GC systems of dwarfs, which probably have not experienced many recent major mergers, suggests that low-mass halos were inefficient at retaining

  19. SDSS-IV MaNGA: the spectroscopic discovery of strongly lensed galaxies

    Talbot, Michael S.; Brownstein, Joel R.; Bolton, Adam S.; Bundy, Kevin; Andrews, Brett H.; Cherinka, Brian; Collett, Thomas E.; More, Anupreeta; More, Surhud; Sonnenfeld, Alessandro; Vegetti, Simona; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.

    2018-06-01

    We present a catalogue of 38 spectroscopically detected strong galaxy-galaxy gravitational lens candidates identified in the Sloan Digital Sky Survey IV (SDSS-IV). We were able to simulate narrow-band images for eight of them demonstrating evidence of multiple images. Two of our systems are compound lens candidates, each with two background source-planes. One of these compound systems shows clear lensing features in the narrow-band image. Our sample is based on 2812 galaxies observed by the Mapping Nearby Galaxies at APO (MaNGA) integral field unit (IFU). This Spectroscopic Identification of Lensing Objects (SILO) survey extends the methodology of the Sloan Lens ACS Survey (SLACS) and BOSS Emission-Line Survey (BELLS) to lower redshift and multiple IFU spectra. We searched ˜1.5 million spectra, of which 3065 contained multiple high signal-to-noise ratio background emission-lines or a resolved [O II] doublet, that are included in this catalogue. Upon manual inspection, we discovered regions with multiple spectra containing background emission-lines at the same redshift, providing evidence of a common source-plane geometry which was not possible in previous SLACS and BELLS discovery programs. We estimate more than half of our candidates have an Einstein radius ≳ 1.7 arcsec, which is significantly greater than seen in SLACS and BELLS. These larger Einstein radii produce more extended images of the background galaxy increasing the probability that a background emission-line will enter one of the IFU spectroscopic fibres, making detection more likely.

  20. Bayesian analysis of the dynamic cosmic web in the SDSS galaxy survey

    Leclercq, Florent; Wandelt, Benjamin; Jasche, Jens

    2015-01-01

    Recent application of the Bayesian algorithm \\textsc(borg) to the Sloan Digital Sky Survey (SDSS) main sample galaxies resulted in the physical inference of the formation history of the observed large-scale structure from its origin to the present epoch. In this work, we use these inferences as inputs for a detailed probabilistic cosmic web-type analysis. To do so, we generate a large set of data-constrained realizations of the large-scale structure using a fast, fully non-linear gravitational model. We then perform a dynamic classification of the cosmic web into four distinct components (voids, sheets, filaments, and clusters) on the basis of the tidal field. Our inference framework automatically and self-consistently propagates typical observational uncertainties to web-type classification. As a result, this study produces accurate cosmographic classification of large-scale structure elements in the SDSS volume. By also providing the history of these structure maps, the approach allows an analysis of the origin and growth of the early traces of the cosmic web present in the initial density field and of the evolution of global quantities such as the volume and mass filling fractions of different structures. For the problem of web-type classification, the results described in this work constitute the first connection between theory and observations at non-linear scales including a physical model of structure formation and the demonstrated capability of uncertainty quantification. A connection between cosmology and information theory using real data also naturally emerges from our probabilistic approach. Our results constitute quantitative chrono-cosmography of the complex web-like patterns underlying the observed galaxy distribution

  1. Evidence for merger remnants in early-type host galaxies of low-redshift QSOs

    Bennert, N.; Canalizo, G.; Jungwiert, Bruno; Stockton, A.; Schweizer, F.; Peng, Ch.; Lacy, M.

    2008-01-01

    Roč. 677, č. 2 (2008), s. 846-857 ISSN 0004-637X R&D Projects: GA MŠk(CZ) LC06014 Institutional research plan: CEZ:AV0Z10030501 Keywords : galaxy mergers * quasars * photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 6.331, year: 2008

  2. Investigating the Merger Origin of Early-type Galaxies using Ultra-deep Optical Images

    Duc, P.-A.; Cuillandre, J.-C.; Alatalo, K.; Blitz, L.; Bois, M.; Bournaud, F.; Bureau, M.; Cappellari, M.; Côté, P.; Davies, R. L.; Davis, T. A.; de Zeeuw, P. T.; Emsellem, E.; Ferrarese, L.; Ferriere, E.; Gwyn, S.; Khochfar, S.; Krajnovic, D.; Kuntschner, H.; Lablanche, P.-Y.; MacArthur, L.; McDermid, R. M.; Michel-Dansac, L.; Morganti, R.; Naab, T.; Oosterloo, T.; Sarzi, M.; Scott, N.; Serra, P.; Weijmans, A.; Young, L. M.

    2011-01-01

    The mass assembly of galaxies leaves various imprints on their surroundings, such as shells, streams and tidal tails. The frequency and properties of these fine structures depend on the mechanism driving the mass assembly: e.g. a monolithic collapse, rapid cold-gas accretion followed by violent disk

  3. A General Precipitation-limited L X–T–R Relation among Early-type Galaxies

    Voit, G. Mark; Ma, C. P.; Greene, J.; Goulding, A.; Pandya, V.; Donahue, M.; Sun, M.

    2018-01-01

    The relation between X-ray luminosity (L X) and ambient gas temperature (T) among massive galactic systems is an important cornerstone of both observational cosmology and galaxy-evolution modeling. In the most massive galaxy clusters, the relation is determined primarily by cosmological structure formation. In less massive systems, it primarily reflects the feedback response to radiative cooling of circumgalactic gas. Here we present a simple but powerful model for the L X–T relation as a function of physical aperture R within which those measurements are made. The model is based on the precipitation framework for AGN feedback and assumes that the circumgalactic medium is precipitation-regulated at small radii and limited by cosmological structure formation at large radii. We compare this model with many different data sets and show that it successfully reproduces the slope and upper envelope of the L X–T–R relation over the temperature range from ∼0.2 keV through ≳ 10 {keV}. Our findings strongly suggest that the feedback mechanisms responsible for regulating star formation in individual massive galaxies have much in common with the precipitation-triggered feedback that appears to regulate galaxy-cluster cores.

  4. The SAURON project : XVIII. The integrated UV-line-strength relations of early-type galaxies

    Bureau, Martin; Jeong, Hyunjin; Yi, Sukyoung K.; Schawinski, Kevin; Houghton, Ryan C. W.; Davies, Roger L.; Bacon, Roland; Cappellari, Michele; de Zeeuw, P. Tim; Emsellem, Eric; Falcon-Barroso, Jesus; Krajnovic, Davor; Kuntschner, Harald; McDermid, Richard M.; Peletier, Reynier F.; Sarzi, Marc; Sohn, Young-Jong; Thomas, Daniel; van den Bosch, Remco C. E.; van de Ven, Glenn

    Using far-ultraviolet (FUV) and near-ultraviolet (NUV) photometry from guest investigator programmes on the Galaxy Evolution Explorer (GALEX) satellite, optical photometry from the MDM Observatory and optical integral-field spectroscopy from SAURON, we explore the UV-line-strength relations of the

  5. SDSS-II SUPERNOVA SURVEY: AN ANALYSIS OF THE LARGEST SAMPLE OF TYPE IA SUPERNOVAE AND CORRELATIONS WITH HOST-GALAXY SPECTRAL PROPERTIES

    Wolf, Rachel C.; Gupta, Ravi R.; Sako, Masao; Fischer, John A.; March, Marisa C.; Fischer, Johanna-Laina; D’Andrea, Chris B.; Smith, Mathew; Kessler, Rick; Scolnic, Daniel M.; Jha, Saurabh W.; Campbell, Heather; Nichol, Robert C.; Olmstead, Matthew D.; Richmond, Michael; Schneider, Donald P.

    2016-01-01

    Using the largest single-survey sample of Type Ia supernovae (SNe Ia) to date, we study the relationship between properties of SNe Ia and those of their host galaxies, focusing primarily on correlations with Hubble residuals (HRs). Our sample consists of 345 photometrically classified or spectroscopically confirmed SNe Ia discovered as part of the SDSS-II Supernova Survey (SDSS-SNS). This analysis utilizes host-galaxy spectroscopy obtained during the SDSS-I/II spectroscopic survey and from an ancillary program on the SDSS-III Baryon Oscillation Spectroscopic Survey that obtained spectra for nearly all host galaxies of SDSS-II SN candidates. In addition, we use photometric host-galaxy properties from the SDSS-SNS data release such as host stellar mass and star formation rate. We confirm the well-known relation between HR and host-galaxy mass and find a 3.6 σ significance of a nonzero linear slope. We also recover correlations between HR and host-galaxy gas-phase metallicity and specific star formation rate as they are reported in the literature. With our large data set, we examine correlations between HR and multiple host-galaxy properties simultaneously and find no evidence of a significant correlation. We also independently analyze our spectroscopically confirmed and photometrically classified SNe Ia and comment on the significance of similar combined data sets for future surveys.

  6. The Masses and Stellar Content of Nuclei in Early-Type Galaxies from Multi-Band Photometry and Spectroscopy

    Spengler, Chelsea; Côté, Patrick; Roediger, Joel; Ferrarese, Laura; Sánchez-Janssen, Rubén; Toloba, Elisa; Liu, Yiqing; Guhathakurta, Puragra; Cuillandre, Jean-Charles; Gwyn, Stephen; Zirm, Andrew; Muñoz, Roberto; Puzia, Thomas; Lançon, Ariane; Peng, Eric; Mei, Simona; Powalka, Mathieu

    2018-01-01

    It is now established that most, if not all, massive galaxies host central supermassive black holes (SMBHs), and that these SMBHs are linked to the growth their host galaxies as shown by several scaling relations. Within the last couple of decades, it has become apparent that most lower-mass galaxies without obvious SMBHs nevertheless contain some sort of central massive object in the form of compact stellar nuclei that also follow identical (or similar) scaling relations. These nuclei are challenging to study given their small sizes and relatively faint magnitudes, but understanding their origins and relationship to their hosts is critical to gaining a more complete picture of galaxy evolution. To that end, we highlight selected results from an analysis of 39 nuclei and their early-type hosts in the Virgo Cluster using ten broadband filters: F300W, F475W, F850LP, F160W, u*griz, and Ks. We estimate masses, metallicities and ages using simple stellar population (SSP) models. For 19 nuclei, we compare to SSP parameters derived from Keck and Gemini spectra and find reasonable agreement between the photometric and spectroscopic metallicity: the RMS scatter is 0.3 dex. We reproduce the nucleus-galaxy mass fraction of 0.33 ± 0.08% for galaxy stellar masses 108.4-1010.3 M⊙ with a typical precision of ~35% for the nuclei masses. Based on available model predictions, there is no single preferred formation scenario for nuclei, suggesting that nuclei are formed stochastically through a mix of processes. Nuclei metallicities are statistically identical to those of their hosts, appearing 0.07 ± 0.3 dex more metal-rich on average — although, omitting galaxies with unusual origins (i.e., compact ellipticals), nuclei are 0.20 ± 0.28 dex more metal-rich. We find no clear age difference between nuclei and their galaxies, with nuclei displaying a broad range of ages. Interestingly, we find that the most massive nuclei may be flatter and more closely aligned with the semi

  7. The Dark Side of Galaxy Color: evidence from new SDSS measurements of galaxy clustering and lensing

    Hearin, Andrew P.; Watson, Douglas F.; Becker, Matthew R.; Reyes, Reinabelle; Berlind, Andreas A.; Zentner, Andrew R.

    2013-01-01

    The age matching model has recently been shown to predict correctly the luminosity L and g-r color of galaxies residing within dark matter halos. The central tenet of the model is intuitive: older halos tend to host galaxies with older stellar populations. In this paper, we demonstrate that age matching also correctly predicts the g-r color trends exhibited in a wide variety of statistics of the galaxy distribution for stellar mass M* threshold samples. In particular, we present new measureme...

  8. Panchromatic properties of 99 000 galaxies detected by SDSS, and (some by) ROSAT, GALEX, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS surveys

    Obric, M.; Ivezic, Z.; Best, P. N.; Lupton, R. H.; Tremonti, C.; Brinchmann, J.; Agueeros, M. A.; Knapp, G. R.; Gunn, J. E.; Rockosi, C. M.; Schlegel, D.; Finkbeiner, D.; Gacesa, M.; Smolcic, V.; Anderson, S. F.; Voges, W.; Juric, M.; Siverd, R. J.; Steinhardt, W.; Jagoda, A. S.; Blanton, M. R.; Schneider, D. P.

    2006-01-01

    We discuss the panchromatic properties of 99 088 galaxies selected from the Sloan Digital Sky Survey (SDSS) Data Release 1 'main' spectroscopic sample ( a flux-limited sample for 1360 deg(2)). These galaxies are positionally matched to sources detected by ROSAT, Galaxy Evolution Explorer (GALEX),

  9. Probing Minor-merger-driven Star Formation In Early-type Galaxies Using Spatially-resolved Spectro-photometric Studies

    Kaviraj, Sugata; Crockett, M.; Silk, J.; O'Connell, R. W.; Whitmore, B.; Windhorst, R.; Cappellari, M.; Bureau, M.; Davies, R.

    2012-01-01

    Recent studies that leverage the rest-frame ultraviolet (UV) spectrum have revealed widespread recent star formation in early-type galaxies (ETGs), traditionally considered to be old, passively-evolving systems. This recent star formation builds 20% of the ETG stellar mass after z 1, driven by repeated minor mergers between ETGs and small, gas-rich satellites. We demonstrate how spatially-resolved studies, using a combination of high-resolution UV-optical imaging and integral-field spectroscopy (IFS), is a powerful tool to quantify the assembly history of individual ETGs and elucidate the poorly-understood minor-merger process. Using a combination of WFC3 UV-optical (2500-8200 angstroms) imaging and IFS from the SAURON project of the ETG NGC 4150, we show that this galaxy experienced a merger with mass ratio 1:15 around 0.9 Gyr ago, which formed 3% of its stellar mass and a young kinematically-decoupled core. A UV-optical analysis of its globular cluster system shows that the bulk of the stars locked up in these clusters likely formed 6-7 Gyrs in the past. We introduce a new HST-WFC3 programme, approved in Cycle 19, which will leverage similar UV-optical imaging of a representative sample of nearby ETGs from SAURON to study the recent star formation and its drivers in unprecedented detail and put definitive constraints on minor-merger-driven star formation in massive galaxies at late epochs.

  10. Active Galactic Nuclei Feedback and the Origin and Fate of the Hot Gas in Early-type Galaxies

    Pellegrini, Silvia; Ciotti, Luca; Negri, Andrea; Ostriker, Jeremiah P.

    2018-04-01

    A recent determination of the relationships between the X-ray luminosity of the ISM (L X) and the stellar and total mass for a sample of nearby early-type galaxies (ETGs) is used to investigate the origin of the hot gas, via a comparison with the results of hydrodynamical simulations of the ISM evolution for a large set of isolated ETGs. After the epoch of major galaxy formation (after z ≃ 2), the ISM is replenished by stellar mass losses and SN ejecta, at the rate predicted by stellar evolution, and is depleted by star formation; it is heated by the thermalization of stellar motions, SNe explosions, and the mechanical (from winds) and radiative AGN feedback. The models agree well with the observed relations, even for the largely different L X values at the same mass, thanks to the sensitivity of the gas flow to many galaxy properties; this holds for models including AGN feedback, and those without. Therefore, the mass input from the stellar population is able to account for a major part of the observed L X; and AGN feedback, while very important to maintain massive ETGs in a time-averaged quasi-steady state, keeping low star formation and the black hole mass, does not dramatically alter the gas content originating in stellar recycled material. These conclusions are based on theoretical predictions for the stellar population contributions in mass and energy, and on a self-consistent modeling of AGN feedback.

  11. SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems

    Eisenstein, Daniel J.; Weinberg, David H.; Agol, Eric; Aihara, Hiroaki; Prieto, Carlos Allende; Anderson, Scott F.; Arns, James A.; Aubourg, Eric; Bailey, Stephen; Balbinot, Eduardo; Barkhouser, Robert

    2011-01-01

    Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of the Milky Way, and the population of giant planets around other stars. The Baryon Oscillation Spectroscopic Survey (BOSS) will measure redshifts of 1.5 million massive galaxies and Lyα forest spectra of 150,000 quasars, using the baryon acoustic oscillation (BAO) feature of large scale structure to obtain percent-level determinations of the distance scale and Hubble expansion rate at z 5 evolved, late-type stars, measuring separate abundances for ∼ 15 elements per star and creating the first high-precision spectroscopic survey of all Galactic stellar populations (bulge, bar, disks, halo) with a uniform set of stellar tracers and spectral diagnostics. The Multi-object APO Radial Velocity Large-area Survey (MARVELS) will monitor radial velocities of more than 8000 FGK stars with the sensitivity and cadence (10-40 m s -1 , ∼ 24 visits per star) needed to detect giant planets with periods up to two years, providing an unprecedented data set for understanding the formation and dynamical evolution of giant planet systems. As of January 2011, SDSS-III has obtained spectra of more than 240,000 galaxies, 29,000 z (ge) 2.2 quasars, and 140,000 stars, including 74,000 velocity measurements of 2580 stars for MARVELS. In keeping with SDSS tradition, SDSS-III will provide regular public releases of all its data, beginning with SDSS Data Release 8 (DR8) in January 2011.

  12. SDSS-IV MaNGA: faint quenched galaxies - I. Sample selection and evidence for environmental quenching

    Penny, Samantha J.; Masters, Karen L.; Weijmans, Anne-Marie; Westfall, Kyle B.; Bershady, Matthew A.; Bundy, Kevin; Drory, Niv; Falcón-Barroso, Jesús; Law, David; Nichol, Robert C.; Thomas, Daniel; Bizyaev, Dmitry; Brownstein, Joel R.; Freischlad, Gordon; Gaulme, Patrick; Grabowski, Katie; Kinemuchi, Karen; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Roman-Lopes, Alexandre; Pan, Kaike; Simmons, Audrey; Wake, David A.

    2016-11-01

    Using kinematic maps from the Sloan Digital Sky Survey (SDSS) Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we reveal that the majority of low-mass quenched galaxies exhibit coherent rotation in their stellar kinematics. Our sample includes all 39 quenched low-mass galaxies observed in the first year of MaNGA. The galaxies are selected with Mr > -19.1, stellar masses 109 M⊙ 1.9. They lie on the size-magnitude and σ-luminosity relations for previously studied dwarf galaxies. Just six (15 ± 5.7 per cent) are found to have rotation speeds ve, rot 5 × 1010 M⊙), supporting the hypothesis that galaxy-galaxy or galaxy-group interactions quench star formation in low-mass galaxies. The local bright galaxy density for our sample is ρproj = 8.2 ± 2.0 Mpc-2, compared to ρproj = 2.1 ± 0.4 Mpc-2 for a star-forming comparison sample, confirming that the quenched low-mass galaxies are preferentially found in higher density environments.

  13. Early-type galaxies: mass-size relation at z ˜ 1.3 for different environments

    Raichoor, A.; Mei, S.; Stanford, S. A.; Holden, B. P.; Nakata, F.; Rosati, P.; Shankar, F.; Tanaka, M.; Ford, H.; Huertas-Company, M.; Illingworth, G.; Kodama, T.; Postman, M.; Rettura, A.; Blakeslee, J. P.; Demarco, R.; Jee, M. J.; White, R. L.

    2011-12-01

    We combine multi-wavelength data of the Lynx superstructure and GOODS/CDF-S to build a sample of 75 visually selected early-type galaxies (ETGs), spanning different environments (cluster/group/field) at z ˜ 1.3. By estimating their mass, age (SED fitting, with a careful attention to the stellar population model used) and size, we are able to probe the dependence on the environment of the mass-size relation. We find that, for ETGs with 10^{10} < M / M_⊙ < 10^{11.5}, (1) the mass-size relation in the field did not evolve overall from z ˜ 1.3 to present; (2) the mass-size relation in cluster/group environments at z ˜ 1.3 lies at smaller sizes than the local mass-size relation (R_{e,z ˜ 1.3}/R_{e,z = 0} ˜ 0.6-0.8).

  14. Detection of Enhanced Central Mass-to-light Ratios in Low-mass Early-type Galaxies: Evidence for Black Holes?

    Pechetti, Renuka; Seth, Anil; Cappellari, Michele; McDermid, Richard; den Brok, Mark; Mieske, Steffen; Strader, Jay

    2017-11-01

    We present dynamical measurements of the central mass-to-light ratio (M/L) of a sample of 27 low-mass early-type {{ATLAS}}3{{D}} galaxies. We consider all {{ATLAS}}3{{D}} galaxies with 9.7 text{}}M/L{{s}} are higher than dynamical {\\text{}}M/L{{s}} derived at larger radii and stellar population estimates of the galaxy centers in ˜80% of galaxies, with a median enhancement of ˜14% and a statistical significance of 3.3σ. We show that the enhancement in the central M/L is best described either by the presence of black holes in these galaxies or by radial initial mass function variations. Assuming a black hole model, we derive black hole masses for the sample of galaxies. In two galaxies, NGC 4458 and NGC 4660, the data suggest significantly overmassive black holes, while in most others only upper limits are obtained. We also show that the level of M/L enhancements we see in these early-type galaxy nuclei are consistent with the larger enhancements seen in ultracompact dwarf galaxies (UCDs), supporting the scenario where massive UCDs are created by stripping galaxies of these masses.

  15. SDSS-IV MaNGA: evidence of the importance of AGN feedback in low-mass galaxies

    Penny, Samantha J.; Masters, Karen L.; Smethurst, Rebecca; Nichol, Robert C.; Krawczyk, Coleman M.; Bizyaev, Dmitry; Greene, Olivia; Liu, Charles; Marinelli, Mariarosa; Rembold, Sandro B.; Riffel, Rogemar A.; Ilha, Gabriele da Silva; Wylezalek, Dominika; Andrews, Brett H.; Bundy, Kevin; Drory, Niv; Oravetz, Daniel; Pan, Kaike

    2018-05-01

    We present new evidence for AGN feedback in a subset of 69 quenched low-mass galaxies (M⋆ ≲ 5 × 109 M⊙, Mr > -19) selected from the first 2 yr of the Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at APO (SDSS-IV MaNGA) survey. The majority (85 per cent) of these quenched galaxies appear to reside in a group environment. We find six galaxies in our sample that appear to have an active AGN that is preventing on-going star formation; this is the first time such a feedback mechanism has been observed in this mass range. Interestingly, five of these six galaxies have an ionized gas component that is kinematically offset from their stellar component, suggesting the gas is either recently accreted or outflowing. We hypothesize these six galaxies are low-mass equivalents to the `red geysers' observed in more massive galaxies. Of the other 63 galaxies in the sample, we find 8 do appear for have some low level, residual star formation, or emission from hot, evolved stars. The remaining galaxies in our sample have no detectable ionized gas emission throughout their structures, consistent with them being quenched. This work shows the potential for understanding the detailed physical properties of dwarf galaxies through spatially resolved spectroscopy.

  16. Modelling dust rings in early-type galaxies through a sequence of radiative transfer simulations and 2D image fitting

    Bonfini, P.; González-Martín, O.; Fritz, J.; Bitsakis, T.; Bruzual, G.; Sodi, B. Cervantes

    2018-05-01

    A large fraction of early-type galaxies (ETGs) host prominent dust features, and central dust rings are arguably the most interesting among them. We present here `Lord Of The Rings' (LOTR), a new methodology which allows to integrate the extinction by dust rings in a 2D fitting modelling of the surface brightness distribution. Our pipeline acts in two steps, first using the surface fitting software GALFIT to determine the unabsorbed stellar emission, and then adopting the radiative transfer code SKIRT to apply dust extinction. We apply our technique to NGC 4552 and NGC 4494, two nearby ETGs. We show that the extinction by a dust ring can mimic, in a surface brightness profile, a central point source (e.g. an unresolved nuclear stellar cluster or an active galactic nucleus; AGN) superimposed to a `core' (i.e. a central flattening of the stellar light commonly observed in massive ETGs). We discuss how properly accounting for dust features is of paramount importance to derive correct fluxes especially for low luminosity AGNs (LLAGNs). We suggest that the geometries of dust features are strictly connected with how relaxed is the gravitational potential, i.e. with the evolutionary stage of the host galaxy. Additionally, we find hints that the dust mass contained in the ring relates to the AGN activity.

  17. Dark matter contraction and stellar-mass-to-light ratio gradients in massive early-type galaxies

    Oldham, Lindsay J.; Auger, Matthew W.

    2018-05-01

    We present models for the dark and luminous mass structure of 12 strong lensing early-type galaxies. We combine pixel-based modelling of multiband Hubble Space Telescope imaging with Jeans modelling of kinematics obtained from Keck/ESI spectra to disentangle the dark and luminous contributions to the mass. Assuming a generalised NFW (gNFW) profile for the dark matter halo and a spatially constant stellar-mass-to-light ratio ϒ⋆ for the baryonic mass, we infer distributions for ϒ⋆ consistent with initial mass functions (IMFs) that are heavier than the Milky Way's (with a global mean mismatch parameter relative to a Chabrier IMF μαc = 1.80 ± 0.14) and halo inner density slopes that span a large range but are generally cuspier than the dark-matter-only prediction (μ _{γ ^' }} = 2.01_{-0.22}^{+0.19}). We investigate possible reasons for overestimating the halo slope, including the neglect of spatially varying stellar-mass-to-light ratios and/or stellar orbital anisotropy, and find that a quarter of the systems prefer radially declining stellar-mass-to-light ratio gradients, but that the overall effect on our inference on the halo slope is small. We suggest a coherent explanation of these results in the context of inside-out galaxy growth, and that the relative importance of different baryonic processes in shaping the dark halo may depend on halo environment.

  18. THE CLUSTERING OF GALAXIES IN THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY: LUMINOSITY AND COLOR DEPENDENCE AND REDSHIFT EVOLUTION

    Guo Hong; Zehavi, Idit [Department of Astronomy, Case Western Reserve University, OH 44106 (United States); Zheng Zheng [Department of Physics and Astronomy, University of Utah, UT 84112 (United States); Weinberg, David H. [Department of Astronomy and CCAPP, Ohio State University, Columbus, OH 43210 (United States); Berlind, Andreas A. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Blanton, Michael [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States); Chen Yanmei [Department of Astronomy, Nanjing University, Nanjing 210093 (China); Eisenstein, Daniel J.; McBride, Cameron K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Ho, Shirley; Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Kazin, Eyal [Center for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122 (Australia); Manera, Marc; Maraston, Claudia; Percival, Will J.; Ross, Ashley J.; Samushia, Lado [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Nuza, Sebastian E. [Leibniz-Institut fuer Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Padmanabhan, Nikhil; Parejko, John K. [Department of Physics, Yale University, 260 Whitney Ave, New Haven, CT 06520 (United States); and others

    2013-04-20

    We measure the luminosity and color dependence and the redshift evolution of galaxy clustering in the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey Ninth Data Release. We focus on the projected two-point correlation function (2PCF) of subsets of its CMASS sample, which includes about 260,000 galaxies over {approx}3300 deg{sup 2} in the redshift range 0.43 < z < 0.7. To minimize the selection effect on galaxy clustering, we construct well-defined luminosity and color subsamples by carefully accounting for the CMASS galaxy selection cuts. The 2PCF of the whole CMASS sample, if approximated by a power-law, has a correlation length of r{sub 0} = 7.93 {+-} 0.06 h {sup -1} Mpc and an index of {gamma} = 1.85 {+-} 0.01. Clear dependences on galaxy luminosity and color are found for the projected 2PCF in all redshift bins, with more luminous and redder galaxies generally exhibiting stronger clustering and steeper 2PCF. The color dependence is also clearly seen for galaxies within the red sequence, consistent with the behavior of SDSS-II main sample galaxies at lower redshifts. At a given luminosity (k + e corrected), no significant evolution of the projected 2PCFs with redshift is detected for red sequence galaxies. We also construct galaxy samples of fixed number density at different redshifts, using redshift-dependent magnitude thresholds. The clustering of these galaxies in the CMASS redshift range is found to be consistent with that predicted by passive evolution. Our measurements of the luminosity and color dependence and redshift evolution of galaxy clustering will allow for detailed modeling of the relation between galaxies and dark matter halos and new constraints on galaxy formation and evolution.

  19. The SLUGGS survey: a comparison of total-mass profiles of early-type galaxies from observations and cosmological simulations, to ˜4 effective radii

    Bellstedt, Sabine; Forbes, Duncan A.; Romanowsky, Aaron J.; Remus, Rhea-Silvia; Stevens, Adam R. H.; Brodie, Jean P.; Poci, Adriano; McDermid, Richard; Alabi, Adebusola; Chevalier, Leonie; Adams, Caitlin; Ferré-Mateu, Anna; Wasserman, Asher; Pandya, Viraj

    2018-06-01

    We apply the Jeans Anisotropic Multi-Gaussian Expansion dynamical modelling method to SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey data of early-type galaxies in the stellar mass range 1010 physical processes shaping the mass distributions of galaxies in cosmological simulations are still incomplete. For galaxies with M* > 1010.7 M⊙ in the Magneticum simulations, we identify a significant anticorrelation between total-mass density profile slopes and the fraction of stellar mass formed ex situ (i.e. accreted), whereas this anticorrelation is weaker for lower stellar masses, implying that the measured total-mass density slopes for low-mass galaxies are less likely to be determined by merger activity.

  20. The ATLAS3D project - VIII. Modelling the formation and evolution of fast and slow rotator early-type galaxies within ΛCDM

    Khochfar, Sadegh; Emsellem, Eric; Serra, Paolo; Bois, Maxime; Alatalo, Katherine; Bacon, R.; Blitz, Leo; Bournaud, Frédéric; Bureau, M.; Cappellari, Michele; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Krajnović, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Weijmans, Anne-Marie; Young, Lisa M.

    2011-01-01

    We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical Λcold dark matter (ΛCDM) scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed via λR. Within

  1. The ATLAS3D project - XXI. Correlations between gradients of local escape velocity and stellar populations in early-type galaxies

    Scott, Nicholas; Cappellari, Michele; Davies, Roger L.; Kleijn, Gijs Verdoes; Bois, Maxime; Alatalo, Katherine; Blitz, Leo; Bournaud, Frédéric; Bureau, Martin; Crocker, Alison; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    We explore the connection between the local escape velocity, Vesc, and the stellar population properties in the ATLAS3D survey, a complete, volume-limited sample of nearby early-type galaxies. We make use of ugriz photometry to construct Multi-Gaussian Expansion models of the surface brightnesses of

  2. The ATLAS(3D) project : XXI. Correlations between gradients of local escape velocity and stellar populations in early-type galaxies

    Scott, Nicholas; Cappellari, Michele; Davies, Roger L.; Kleijn, Gijs Verdoes; Bois, Maxime; Alatalo, Katherine; Blitz, Leo; Bournaud, Frederic; Bureau, Martin; Crocker, Alison; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnovic, Davor; Kuntschner, Harald; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2013-01-01

    We explore the connection between the local escape velocity, V-esc, and the stellar population properties in the ATLAS(3D) survey, a complete, volume-limited sample of nearby early-type galaxies. We make use of ugriz photometry to construct Multi-Gaussian Expansion models of the surface brightnesses

  3. The ATLAS(3D) project : VIII. Modelling the formation and evolution of fast and slow rotator early-type galaxies within lambda CDM

    Khochfar, Sadegh; Emsellem, Eric; Serra, Paolo; Bois, Maxime; Alatalo, Katherine; Bacon, R.; Blitz, Leo; Bournaud, Frederic; Bureau, M.; Cappellari, Michele; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Krajnovic, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Weijmans, Anne-Marie; Young, Lisa M.

    2011-01-01

    We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical Lambda cold dark matter (Lambda CDM) scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed

  4. THE CONVERSION OF LATE-TYPE INTO EARLY-TYPE DWARF GALAXIES BY RAM-PRESSURE STRIPPING IN THE FORNAX CLUSTER

    De Rijcke, S.; Van Hese, E.; Buyle, P.

    2010-01-01

    We put to the test the hypothesis that the Fornax cluster dwarf galaxies are mostly a relatively recently acquired population, of which the star-forming, late-type members are converted into quiescent, early-type ones by ram-pressure stripping while being on orbits that plunge inside the inner few hundred kiloparsecs of the cluster. We construct dynamical models with different anisotropy profiles for the dwarf galaxy population and show that only extremely radially anisotropic orbital distributions are in agreement with the available morphological, positional, and kinematical data, especially with the radially increasing late-to-early-type ratio. This corroborates the idea that the Fornax cluster dwarfs are an infall population and that environmental factors, in this case ram-pressure stripping, play a prominent role in converting late-type dwarfs into early-type ones.

  5. Early-type galaxies at intermediate redshift observed with Hubble space telescope WFC3: perspectives on recent star formation

    Rutkowski, Michael J. [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Jeong, Hyunjin; Yi, Sukyoung K. [Department of Astronomy, Yonsei University 134, Shinchon-dong, Sudaemun-gu, Seoul 120-179 (Korea, Republic of); Cohen, Seth H.; Windhorst, Rogier A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Kaviraj, Sugata [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Ryan, Russell E. Jr.; Koekemoer, Anton [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Hathi, Nimish P. [Aix Marseille Université, CNRS, LAM, UMR 7326, F-13388, Marseille (France); Dopita, Michael A. [Research School of Physics and Astronomy, The Australian National University, Canberra, ACT 2611 (Australia)

    2014-12-01

    We present an analysis of the stellar populations of 102 visually selected early-type galaxies (ETGs) with spectroscopic redshifts (0.35 ≲ z ≲ 1.5) from observations in the Early Release Science program with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). We fit one- and two-component synthetic stellar models to the ETGs UV-optical-near-IR spectral energy distributions and find that a large fraction (∼40%) are likely to have experienced a minor (f{sub YC} ≲ 10% of stellar mass) burst of recent (t{sub YC} ≲ 1 Gyr) star formation. The measured age and mass fraction of the young stellar populations do not strongly trend with measurements of galaxy morphology. We note that massive (M > 10{sup 10.5} M {sub ☉}) recent star-forming ETGs appear to have larger sizes. Furthermore, high-mass, quiescent ETGs identified with likely companions populate a distinct region in the size-mass parameter space, in comparison with the distribution of massive ETGs with evidence of recent star formation (RSF). We conclude that both mechanisms of quenching star formation in disk-like ETGs and (gas-rich, minor) merger activity contribute to the formation of young stars and the size-mass evolution of intermediate redshift ETGs. The number of ETGs for which we have both HST WFC3 panchromatic (especially UV) imaging and spectroscopically confirmed redshifts is relatively small, therefore, a conclusion about the relative roles of both of these mechanisms remains an open question.

  6. THE NEXT GENERATION VIRGO CLUSTER SURVEY XVI: THE ANGULAR MOMENTUM OF DWARF EARLY-TYPE GALAXIES FROM GLOBULAR CLUSTER SATELLITES

    Toloba, Elisa; Guhathakurta, Puragra [UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Li, Biao; Peng, Eric W.; Zhang, Hongxin [Department of Astronomy, Peking University, Beijing 100871 (China); Ferrarese, Laura; Côté, Patrick; Gwyn, Stephen [National Research Council of Canada, Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Emsellem, Eric [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748, Garching (Germany); Boselli, Alessandro [Laboratoire d’Astrophysique de Marseille-LAM, Université d’Aix-Marseille and CNRS, UMR 7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Cuillandre, Jean-Charles [CEA/IRFU/SAP, Laboratoire AIM Paris-Saclay, CNRS/INSU, Université Paris Diderot, Observatoire de Paris, PSL Research University, F-91191 Gif-sur-Yvette Cedex (France); Jordan, Andres [Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Vicuna Mackenna 4860, 7820436 Macul, Santiago (Chile); Liu, Chengze, E-mail: toloba@ucolick.org [Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2016-05-01

    We analyze the kinematics of six Virgo cluster dwarf early-type galaxies (dEs) from their globular cluster (GC) systems. We present new Keck/DEIMOS spectroscopy for three of them and re-analyze the data found in the literature for the remaining three. We use two independent methods to estimate the rotation amplitude ( V {sub rot}) and velocity dispersion ( σ {sub GC}) of the GC systems and evaluate their statistical significance by simulating non-rotating GC systems with the same number of GC satellites and velocity uncertainties. Our measured kinematics agree with the published values for the three galaxies from the literature and, in all cases, some rotation is measured. However, our simulations show that the null hypothesis of being non-rotating GC systems cannot be ruled out. In the case of VCC 1861, the measured V {sub rot} and the simulations indicate that it is not rotating. In the case of VCC 1528, the null hypothesis can be marginally ruled out, and thus it might be rotating although further confirmation is needed. In our analysis, we find that, in general, the measured V {sub rot} tends to be overestimated and the measured σ {sub GC} tends to be underestimated by amounts that depend on the intrinsic V {sub rot}/ σ {sub GC}, the number of observed GCs ( N {sub GC}), and the velocity uncertainties. The bias is negligible when N {sub GC} ≳ 20. In those cases where a large N {sub GC} is not available, it is imperative to obtain data with small velocity uncertainties. For instance, errors of ≤2 km s{sup −1} lead to V {sub rot} < 10 km s{sup −1} for a system that is intrinsically not rotating.

  7. Polar ring galaxies in the Galaxy Zoo

    Finkelman, Ido; Funes, José G.; Brosch, Noah

    2012-05-01

    We report observations of 16 candidate polar-ring galaxies (PRGs) identified by the Galaxy Zoo project in the Sloan Digital Sky Survey (SDSS) data base. Deep images of five galaxies are available in the SDSS Stripe82 data base, while to reach similar depth we observed the remaining galaxies with the 1.8-m Vatican Advanced Technology Telescope. We derive integrated magnitudes and u-r colours for the host and ring components and show continuum-subtracted Hα+[N II] images for seven objects. We present a basic morphological and environmental analysis of the galaxies and discuss their properties in comparison with other types of early-type galaxies. Follow-up photometric and spectroscopic observations will allow a kinematic confirmation of the nature of these systems and a more detailed analysis of their stellar populations.

  8. DARK MATTER CONTRACTION AND THE STELLAR CONTENT OF MASSIVE EARLY-TYPE GALAXIES: DISFAVORING 'LIGHT' INITIAL MASS FUNCTIONS

    Auger, M. W.; Treu, T.; Gavazzi, R.; Bolton, A. S.; Koopmans, L. V. E.; Marshall, P. J.

    2010-01-01

    We use stellar dynamics, strong lensing, stellar population synthesis models, and weak lensing shear measurements to constrain the dark matter (DM) profile and stellar mass in a sample of 53 massive early-type galaxies. We explore three DM halo models (unperturbed Navarro, Frenk, and White (NFW) halos and the adiabatic contraction models of Blumenthal and Gnedin) and impose a model for the relationship between the stellar and virial mass (i.e., a relationship for the star formation efficiency as a function of halo mass). We show that, given our model assumptions, the data clearly prefer a Salpeter-like initial mass function (IMF) over a lighter IMF (e.g., Chabrier or Kroupa), irrespective of the choice of DM halo. In addition, we find that the data prefer at most a moderate amount of adiabatic contraction (Blumenthal adiabatic contraction is strongly disfavored) and are only consistent with no adiabatic contraction (i.e., an NFW halo) if a mass-dependent IMF is assumed, in the sense of a more massive normalization of the IMF for more massive halos.

  9. SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems

    Eisenstein, Daniel J.; /Arizona U., Astron. Dept. - Steward Observ. /Harvard U., Phys. Dept.; Weinberg, David H.; /Ohio State U.; Agol, Eric; /Washington U., Seattle, Astron. Dept.; Aihara, Hiroaki; /Tokyo U.; Prieto, Carlos Allende; /Laguna U., Tenerife; Anderson, Scott F.; /Washington U., Seattle, Astron. Dept.; Arns, James A.; /Michigan U.; Aubourg, Eric; /APC, Paris /DAPNIA, Saclay; Bailey, Stephen; /LBL, Berkeley; Balbinot, Eduardo; /Rio Grande do Sul U. /Rio de Janeiro Observ.; Barkhouser, Robert; /Johns Hopkins U. /Michigan State U.

    2011-01-01

    Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of the Milky Way, and the population of giant planets around other stars. The Baryon Oscillation Spectroscopic Survey (BOSS) will measure redshifts of 1.5 million massive galaxies and Ly{alpha} forest spectra of 150,000 quasars, using the baryon acoustic oscillation (BAO) feature of large scale structure to obtain percent-level determinations of the distance scale and Hubble expansion rate at z < 0.7 and at z {approx} 2.5. SEGUE-2, a now-completed continuation of the Sloan Extension for Galactic Understanding and Exploration, measured medium-resolution (R = {lambda}/{Delta}{lambda} 1800) optical spectra of 118,000 stars in a variety of target categories, probing chemical evolution, stellar kinematics and substructure, and the mass profile of the dark matter halo from the solar neighborhood to distances of 100 kpc. APOGEE, the Apache Point Observatory Galactic Evolution Experiment, will obtain high-resolution (R {approx} 30,000), high signal-to-noise ratio (S/N {ge} 100 per resolution element), H-band (1.51 {micro}m < {lambda} < 1.70 {micro}m) spectra of 10{sup 5} evolved, late-type stars, measuring separate abundances for {approx} 15 elements per star and creating the first high-precision spectroscopic survey of all Galactic stellar populations (bulge, bar, disks, halo) with a uniform set of stellar tracers and spectral diagnostics. The Multi-object APO Radial Velocity Large-area Survey (MARVELS) will monitor radial velocities of more than 8000 FGK stars with the sensitivity and cadence (10-40 m s{sup -1}, {approx} 24 visits per star) needed to detect giant planets with periods up to two years, providing an unprecedented data set for understanding the formation and dynamical evolution of giant planet systems. As of January 2011, SDSS-III has obtained

  10. The Slogan Great Wall from the SDSS Data Release 4

    Deng Xin-Fa; He Ji-Zhou; Luo Cheng-Hong; Wu Ping; Tang Xiao-Xun; He Cong-Gen

    2007-01-01

    Using the MAIN galaxy data from the SDSS Data Release 4 (SDSS4), we further study the Sloan Great Wall by three-dimensional cluster analysis. Because the basic properties of Main galaxies change with redshift, we select 50942 Main galaxies having the same redshift region (0.07 ≤ z ≤ 0.09) as the Sloan Great Wall from the Main galaxy sample, and construct our SubMain sample. From the SubMain sample, 2013 isolated galaxies are identified at dimensionless radius r = 1.4. We perform the comparative studies of galaxy properties among the Sloan Great Wall, isolated galaxies and the SubMain sample in different redshift bins. It turns out that the statistical properties of luminosities and sizes of galaxies for the Sloan Great Wall, isolated galaxies and the SubMain sample are almost the same, the proportion of early-type isolated galaxies is relatively low. We also d that mean color of member galaxies of the Sloan Great Wall is redder than that of isolated galaxies. These results indicate that some properties of galaxies may be closely correlated with the environment or clustering. (author)

  11. THE SL2S GALAXY-SCALE LENS SAMPLE. II. COSMIC EVOLUTION OF DARK AND LUMINOUS MASS IN EARLY-TYPE GALAXIES

    Ruff, Andrea J.; Marshall, Philip J.; Treu, Tommaso; Auger, Matthew W.; Gavazzi, Raphael; Brault, Florence

    2011-01-01

    We present a joint gravitational lensing and stellar-dynamical analysis of 11 early-type galaxies (median deflector redshift z d = 0.5) from Strong Lenses in the Legacy Survey (SL2S). Using newly measured redshifts and stellar velocity dispersions from Keck spectroscopy with lens models from Paper I, we derive the total mass-density slope inside the Einstein radius for each of the 11 lenses. The average total density slope is found to be (γ') = 2.16 +0.09 -0.09 (ρ tot ∝r -γ ' ), with an intrinsic scatter of 0.25 +0.10 -0.07 . We also determine the dark matter fraction for each lens within half the effective radius, R eff /2, and find the average-projected dark matter mass fraction to be 0.42 +0.08 -0.08 with a scatter of 0.20 +0.09 -0.07 for a Salpeter initial mass function. By combining the SL2S results with those from the Sloan Lens ACS Survey (median z d = 0.2) and the Lenses Structure and Dynamics Survey (median z d = 0.8), we investigate cosmic evolution of γ' and find a mild trend ∂(γ')/∂z d = -0.25 +0.10 -0.12 . This suggests that the total density profile of massive galaxies has become slightly steeper over cosmic time. If this result is confirmed by larger samples, it would indicate that dissipative processes played some role in the growth of massive galaxies since z ∼ 1.

  12. STELLAR POPULATIONS AND EVOLUTION OF EARLY-TYPE CLUSTER GALAXIES: CONSTRAINTS FROM OPTICAL IMAGING AND SPECTROSCOPY OF z = 0.5–0.9 GALAXY CLUSTERS

    Jørgensen, Inger; Chiboucas, Kristin

    2013-01-01

    has a mean metallicity [M/H] approximately 0.2 dex below that of the other clusters and our low-redshift sample. We confirm our previous result that RXJ0152.7–1357 has a mean abundance ratio [α/Fe] approximately 0.3 dex higher than that of the other clusters. The differences in [M/H] and [α/Fe] between the high-redshift clusters and the low-redshift sample are inconsistent with a passive evolution scenario for early-type cluster galaxies over the redshift interval studied. Low-level star formation may be able to bring the metallicity of MS0451.6–0305 in agreement with the low-redshift sample, while we speculate whether galaxy mergers can lead to sufficiently large changes in the abundance ratios for the RXJ0152.7–1357 galaxies to allow them to reach the low-redshift sample values in the time available.

  13. Comparison of some properties of star forming galaxies and active galactic nuclei between two BOSS galaxy samples from SDSS DR9

    Deng Xin-Fa

    2014-01-01

    Using the LOWZ and CMASS samples of the ninth data release (DR9) from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), I investigate properties of star forming galaxies and active galactic nuclei (AGNs). The CMASS sample seriously suffers from the radial selection effect, even within the redshift 0.44 ≤ z ≤ 0.6, which will likely lead to statistical conclusions in the CMASS sample being less robust. In the LOWZ sample, the fraction of star-forming galaxies is nearly constant from the least dense regime to the densest regime; the AGN fraction is also insensitive to the local environment. In addition, I note that in the LOWZ sample, the distributions of stellar mass and stellar velocity dispersion for star forming galaxies and AGNs are nearly the same

  14. The X-Ray Luminosity Functions of Field Low-Mass X-Ray Binaries in Early-Type Galaxies: Evidence for a Stellar Age Dependence

    Lehmer, B. D.; Berkeley, M.; Zezas, A.; Alexander, D. M.; Basu-Zych, A.; Bauer, F. E.; Brandt, W. N.; Fragos, T.; Hornschemeier, A. E.; Kalogera, V.; hide

    2014-01-01

    We present direct constraints on how the formation of low-mass X-ray binary (LMXB) populations in galactic fields depends on stellar age. In this pilot study, we utilize Chandra and Hubble Space Telescope (HST) data to detect and characterize the X-ray point source populations of three nearby early-type galaxies: NGC 3115, 3379, and 3384. The luminosity-weighted stellar ages of our sample span approximately equal to 3-10 Gyr. X-ray binary population synthesis models predict that the field LMXBs associated with younger stellar populations should be more numerous and luminous per unit stellar mass than older populations due to the evolution of LMXB donor star masses. Crucially, the combination of deep Chandra and HST observations allows us to test directly this prediction by identifying and removing counterparts to X-ray point sources that are unrelated to the field LMXB populations, including LMXBs that are formed dynamically in globular clusters, Galactic stars, and background AGN/galaxies. We find that the "young" early-type galaxy NGC 3384 (approximately equals 2-5 Gyr) has an excess of luminous field LMXBs (L(sub x) approximately greater than (5-10) × 10(exp 37) erg s(exp -1)) per unit K-band luminosity (L(sub K); a proxy for stellar mass) than the "old" early-type galaxies NGC 3115 and 3379 (approximately equals 8-10 Gyr), which results in a factor of 2-3 excess of L(sub X)/L(sub K) for NGC 3384. This result is consistent with the X-ray binary population synthesis model predictions; however, our small galaxy sample size does not allow us to draw definitive conclusions on the evolution field LMXBs in general. We discuss how future surveys of larger galaxy samples that combine deep Chandra and HST data could provide a powerful new benchmark for calibrating X-ray binary population synthesis models.

  15. The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

    Albareti, Franco D.; Allende Prieto, Carlos; Almeida, Andres; Anders, Friedrich; Anderson, Scott; Andrews, Brett H.; Aragón-Salamanca, Alfonso; Argudo-Fernández, Maria; Armengaud, Eric; Aubourg, Eric; Avila-Reese, Vladimir; Badenes, Carles; Bailey, Stephen; Barbuy, Beatriz; Barger, Kat; Barrera-Ballesteros, Jorge; Bartosz, Curtis; Basu, Sarbani; Bates, Dominic; Battaglia, Giuseppina; Baumgarten, Falk; Baur, Julien; Bautista, Julian; Beers, Timothy C.; Belfiore, Francesco; Bershady, Matthew; Bertran de Lis, Sara; Bird, Jonathan C.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael; Blomqvist, Michael; Bolton, Adam S.; Borissova, J.; Bovy, Jo; Nielsen Brandt, William; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Burtin, Etienne; Busca, Nicolás G.; Orlando Camacho Chavez, Hugo; Cano Díaz, M.; Cappellari, Michele; Carrera, Ricardo; Chen, Yanping; Cherinka, Brian; Cheung, Edmond; Chiappini, Cristina; Chojnowski, Drew; Chuang, Chia-Hsun; Chung, Haeun; Cirolini, Rafael Fernando; Clerc, Nicolas; Cohen, Roger E.; Comerford, Julia M.; Comparat, Johan; Correa do Nascimento, Janaina; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D.; Croft, Rupert; Cunha, Katia; Darling, Jeremy; Davidson, James W., Jr.; Dawson, Kyle; Da Costa, Luiz; Da Silva Ilha, Gabriele; Deconto Machado, Alice; Delubac, Timothée; De Lee, Nathan; De la Macorra, Axel; De la Torre, Sylvain; Diamond-Stanic, Aleksandar M.; Donor, John; Downes, Juan Jose; Drory, Niv; Du, Cheng; Du Mas des Bourboux, Hélion; Dwelly, Tom; Ebelke, Garrett; Eigenbrot, Arthur; Eisenstein, Daniel J.; Elsworth, Yvonne P.; Emsellem, Eric; Eracleous, Michael; Escoffier, Stephanie; Evans, Michael L.; Falcón-Barroso, Jesús; Fan, Xiaohui; Favole, Ginevra; Fernandez-Alvar, Emma; Fernandez-Trincado, J. G.; Feuillet, Diane; Fleming, Scott W.; Font-Ribera, Andreu; Freischlad, Gordon; Frinchaboy, Peter; Fu, Hai; Gao, Yang; Garcia, Rafael A.; Garcia-Dias, R.; Garcia-Hernández, D. A.; Garcia Pérez, Ana E.; Gaulme, Patrick; Ge, Junqiang; Geisler, Douglas; Gillespie, Bruce; Gil Marin, Hector; Girardi, Léo; Goddard, Daniel; Gomez Maqueo Chew, Yilen; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Green, Paul; Grier, Catherine J.; Grier, Thomas; Guo, Hong; Guy, Julien; Hagen, Alex; Hall, Matt; Harding, Paul; Harley, R. E.; Hasselquist, Sten; Hawley, Suzanne; Hayes, Christian R.; Hearty, Fred; Hekker, Saskia; Hernandez Toledo, Hector; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Holzer, Parker H.; Hu, Jian; Huber, Daniel; Hutchinson, Timothy Alan; Hwang, Ho Seong; Ibarra-Medel, Héctor J.; Ivans, Inese I.; Ivory, KeShawn; Jaehnig, Kurt; Jensen, Trey W.; Johnson, Jennifer A.; Jones, Amy; Jullo, Eric; Kallinger, T.; Kinemuchi, Karen; Kirkby, David; Klaene, Mark; Kneib, Jean-Paul; Kollmeier, Juna A.; Lacerna, Ivan; Lane, Richard R.; Lang, Dustin; Laurent, Pierre; Law, David R.; Leauthaud, Alexie; Le Goff, Jean-Marc; Li, Chen; Li, Cheng; Li, Niu; Li, Ran; Liang, Fu-Heng; Liang, Yu; Lima, Marcos; Lin, Lihwai; Lin, Lin; Lin, Yen-Ting; Liu, Chao; Long, Dan; Lucatello, Sara; MacDonald, Nicholas; MacLeod, Chelsea L.; Mackereth, J. Ted; Mahadevan, Suvrath; Geimba Maia, Marcio Antonio; Maiolino, Roberto; Majewski, Steven R.; Malanushenko, Olena; Malanushenko, Viktor; Dullius Mallmann, Nícolas; Manchado, Arturo; Maraston, Claudia; Marques-Chaves, Rui; Martinez Valpuesta, Inma; Masters, Karen L.; Mathur, Savita; McGreer, Ian D.; Merloni, Andrea; Merrifield, Michael R.; Meszáros, Szabolcs; Meza, Andres; Miglio, Andrea; Minchev, Ivan; Molaverdikhani, Karan; Montero-Dorta, Antonio D.; Mosser, Benoit; Muna, Demitri; Myers, Adam; Nair, Preethi; Nandra, Kirpal; Ness, Melissa; Newman, Jeffrey A.; Nichol, Robert C.; Nidever, David L.; Nitschelm, Christian; O’Connell, Julia; Oravetz, Audrey; Oravetz, Daniel J.; Pace, Zachary; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John; Paris, Isabelle; Park, Changbom; Peacock, John A.; Peirani, Sebastien; Pellejero-Ibanez, Marcos; Penny, Samantha; Percival, Will J.; Percival, Jeffrey W.; Perez-Fournon, Ismael; Petitjean, Patrick; Pieri, Matthew; Pinsonneault, Marc H.; Pisani, Alice; Prada, Francisco; Prakash, Abhishek; Price-Jones, Natalie; Raddick, M. Jordan; Rahman, Mubdi; Raichoor, Anand; Barboza Rembold, Sandro; Reyna, A. M.; Rich, James; Richstein, Hannah; Ridl, Jethro; Riffel, Rogemar A.; Riffel, Rogério; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodríguez-Torres, Sergio; Rodrigues, Thaíse S.; Roe, Natalie; Lopes, A. Roman; Román-Zúñiga, Carlos; Ross, Ashley J.; Rossi, Graziano; Ruan, John; Ruggeri, Rossana; Runnoe, Jessie C.; Salazar-Albornoz, Salvador; Salvato, Mara; Sanchez, Sebastian F.; Sanchez, Ariel G.; Sanchez-Gallego, José R.; Santiago, Basílio Xavier; Schiavon, Ricardo; Schimoia, Jaderson S.; Schlafly, Eddie; Schlegel, David J.; Schneider, Donald P.; Schönrich, Ralph; Schultheis, Mathias; Schwope, Axel; Seo, Hee-Jong; Serenelli, Aldo; Sesar, Branimir; Shao, Zhengyi; Shetrone, Matthew; Shull, Michael; Silva Aguirre, Victor; Skrutskie, M. F.; Slosar, Anže; Smith, Michael; Smith, Verne V.; Sobeck, Jennifer; Somers, Garrett; Souto, Diogo; Stark, David V.; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Storchi Bergmann, Thaisa; Strauss, Michael A.; Streblyanska, Alina; Stringfellow, Guy S.; Suarez, Genaro; Sun, Jing; Taghizadeh-Popp, Manuchehr; Tang, Baitian; Tao, Charling; Tayar, Jamie; Tembe, Mita; Thomas, Daniel; Tinker, Jeremy; Tojeiro, Rita; Tremonti, Christy; Troup, Nicholas; Trump, Jonathan R.; Unda-Sanzana, Eduardo; Valenzuela, O.; Van den Bosch, Remco; Vargas-Magaña, Mariana; Vazquez, Jose Alberto; Villanova, Sandro; Vivek, M.; Vogt, Nicole; Wake, David; Walterbos, Rene; Wang, Yuting; Wang, Enci; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Weinberg, David H.; Westfall, Kyle B.; Whelan, David G.; Wilcots, Eric; Wild, Vivienne; Williams, Rob A.; Wilson, John; Wood-Vasey, W. M.; Wylezalek, Dominika; Xiao, Ting; Yan, Renbin; Yang, Meng; Ybarra, Jason E.; Yeche, Christophe; Yuan, Fang-Ting; Zakamska, Nadia; Zamora, Olga; Zasowski, Gail; Zhang, Kai; Zhao, Cheng; Zhao, Gong-Bo; Zheng, Zheng; Zheng, Zheng; Zhou, Zhi-Min; Zhu, Guangtun; Zinn, Joel C.; Zou, Hu

    2017-12-01

    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in 2014 July. It pursues three core programs: the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), Mapping Nearby Galaxies at APO (MaNGA), and the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). As well as its core program, eBOSS contains two major subprograms: the Time Domain Spectroscopic Survey (TDSS) and the SPectroscopic IDentification of ERosita Sources (SPIDERS). This paper describes the first data release from SDSS-IV, Data Release 13 (DR13). DR13 makes publicly available the first 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA. It includes new observations from eBOSS, completing the Sloan Extended QUasar, Emission-line galaxy, Luminous red galaxy Survey (SEQUELS), which also targeted variability-selected objects and X-ray-selected objects. DR13 includes new reductions of the SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification, and new reductions of the SDSS-III APOGEE-1 data, improving stellar parameters for dwarf stars and cooler stars. DR13 provides more robust and precise photometric calibrations. Value-added target catalogs relevant for eBOSS, TDSS, and SPIDERS and an updated red-clump catalog for APOGEE are also available. This paper describes the location and format of the data and provides references to important technical papers. The SDSS web site, http://www.sdss.org, provides links to the data, tutorials, examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned ∼6 yr operations of SDSS-IV.

  16. The MASSIVE survey. I. A volume-limited integral-field spectroscopic study of the most massive early-type galaxies within 108 Mpc

    Ma, Chung-Pei [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Greene, Jenny E.; Murphy, Jeremy D. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); McConnell, Nicholas [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Janish, Ryan [Department of Physics, University of California, Berkeley, CA 94720 (United States); Blakeslee, John P. [Dominion Astrophysical Observatory, NRC Herzberg Institute of Astrophysics, Victoria, BC V9E 2E7 (Canada); Thomas, Jens, E-mail: cpma@berkeley.edu [Max Planck-Institute for Extraterrestrial Physics, Giessenbachstr. 1, D-85741 Garching (Germany)

    2014-11-10

    Massive early-type galaxies represent the modern day remnants of the earliest major star formation episodes in the history of the universe. These galaxies are central to our understanding of the evolution of cosmic structure, stellar populations, and supermassive black holes, but the details of their complex formation histories remain uncertain. To address this situation, we have initiated the MASSIVE Survey, a volume-limited, multi-wavelength, integral-field spectroscopic (IFS) and photometric survey of the structure and dynamics of the ∼100 most massive early-type galaxies within a distance of 108 Mpc. This survey probes a stellar mass range M* ≳ 10{sup 11.5} M {sub ☉} and diverse galaxy environments that have not been systematically studied to date. Our wide-field IFS data cover about two effective radii of individual galaxies, and for a subset of them, we are acquiring additional IFS observations on sub-arcsecond scales with adaptive optics. We are also acquiring deep K-band imaging to trace the extended halos of the galaxies and measure accurate total magnitudes. Dynamical orbit modeling of the combined data will allow us to simultaneously determine the stellar, black hole, and dark matter halo masses. The primary goals of the project are to constrain the black hole scaling relations at high masses, investigate systematically the stellar initial mass function and dark matter distribution in massive galaxies, and probe the late-time assembly of ellipticals through stellar population and kinematical gradients. In this paper, we describe the MASSIVE sample selection, discuss the distinct demographics and structural and environmental properties of the selected galaxies, and provide an overview of our basic observational program, science goals and early survey results.

  17. SDSS IV MaNGA: Dependence of Global and Spatially Resolved SFR–M ∗ Relations on Galaxy Properties

    Pan, Hsi-An; Lin, Lihwai; Hsieh, Bau-Ching; Sánchez, Sebastián F.; Ibarra-Medel, Héctor; Boquien, Médéric; Lacerna, Ivan; Argudo-Fernández, Maria; Bizyaev, Dmitry; Cano-Díaz, Mariana; Drory, Niv; Gao, Yang; Masters, Karen; Pan, Kaike; Tabor, Martha; Tissera, Patricia; Xiao, Ting

    2018-02-01

    The galaxy integrated Hα star formation rate–stellar mass relation, or SFR(global)–M *(global) relation, is crucial for understanding star formation history and evolution of galaxies. However, many studies have dealt with SFR using unresolved measurements, which makes it difficult to separate out the contamination from other ionizing sources, such as active galactic nuclei and evolved stars. Using the integral field spectroscopic observations from SDSS-IV MaNGA, we spatially disentangle the contribution from different Hα powering sources for ∼1000 galaxies. We find that, when including regions dominated by all ionizing sources in galaxies, the spatially resolved relation between Hα surface density (ΣHα (all)) and stellar mass surface density (Σ*(all)) progressively turns over at the high Σ*(all) end for increasing M *(global) and/or bulge dominance (bulge-to-total light ratio, B/T). This in turn leads to the flattening of the integrated Hα(global)–M *(global) relation in the literature. By contrast, there is no noticeable flattening in both integrated Hα(H II)–M *(H II) and spatially resolved ΣHα (H II)–Σ*(H II) relations when only regions where star formation dominates the ionization are considered. In other words, the flattening can be attributed to the increasing regions powered by non-star-formation sources, which generally have lower ionizing ability than star formation. An analysis of the fractional contribution of non-star-formation sources to total Hα luminosity of a galaxy suggests a decreasing role of star formation as an ionizing source toward high-mass, high-B/T galaxies and bulge regions. This result indicates that the appearance of the galaxy integrated SFR–M * relation critically depends on their global properties (M *(global) and B/T) and relative abundances of various ionizing sources within the galaxies.

  18. Test of Gravity on Large Scales with Weak Gravitational Lensing and Clustering Measurements of SDSS Luminous Red Galaxies

    Reyes, Reinabelle; Mandelbaum, R.; Seljak, U.; Gunn, J.; Lombriser, L.

    2009-01-01

    We perform a test of gravity on large scales (5-50 Mpc/h) using 70,000 luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS) DR7 with redshifts 0.16galaxy peculiar velocities, and galaxy clustering-- that can discriminate between different theories of gravity and is largely independent of galaxy bias and sigma_8. In particular, E_G is sensitive to the relation between the spatial and temporal scalar perturbations in the space-time metric. While these two potentials are equivalent in concordance cosmology (GR+LCDM) in the absence of anisotropic stress, they are not equivalent in alternative theories of gravity in general, so that different models make different predictions for E_G. We find E_G=0.37±0.05 averaged over scales 5galaxy surveys such as LSST, for which a very high signal-to-noise measurement will be possible.

  19. OVERVIEW OF THE SDSS-IV MaNGA SURVEY: MAPPING NEARBY GALAXIES AT APACHE POINT OBSERVATORY

    Bundy, Kevin [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa 277-8583 (Japan); Bershady, Matthew A.; Wake, David A.; Tremonti, Christy; Diamond-Stanic, Aleksandar M. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Law, David R.; Cherinka, Brian [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Yan, Renbin; Sánchez-Gallego, José R. [Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055 (United States); Drory, Niv [McDonald Observatory, Department of Astronomy, University of Texas at Austin, 1 University Station, Austin, TX 78712-0259 (United States); MacDonald, Nicholas [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Weijmans, Anne-Marie [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Thomas, Daniel; Masters, Karen; Coccato, Lodovico [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth (United Kingdom); Aragón-Salamanca, Alfonso [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Avila-Reese, Vladimir [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, A.P. 70-264, 04510 Mexico D.F. (Mexico); Badenes, Carles [Department of Physics and Astronomy and Pittsburgh Particle Physics, Astrophysics and Cosmology Center (PITT PACC), University of Pittsburgh, 3941 OHara St, Pittsburgh, PA 15260 (United States); Falcón-Barroso, Jésus [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Belfiore, Francesco [Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); and others

    2015-01-01

    We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. MaNGA will investigate the internal kinematic structure and composition of gas and stars in an unprecedented sample of 10,000 nearby galaxies. We summarize essential characteristics of the instrument and survey design in the context of MaNGA's key science goals and present prototype observations to demonstrate MaNGA's scientific potential. MaNGA employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12'' (19 fibers) to 32'' (127 fibers). Two dual-channel spectrographs provide simultaneous wavelength coverage over 3600-10300 Å at R ∼ 2000. With a typical integration time of 3 hr, MaNGA reaches a target r-band signal-to-noise ratio of 4-8 (Å{sup –1} per 2'' fiber) at 23 AB mag arcsec{sup –2}, which is typical for the outskirts of MaNGA galaxies. Targets are selected with M {sub *} ≳ 10{sup 9} M {sub ☉} using SDSS-I redshifts and i-band luminosity to achieve uniform radial coverage in terms of the effective radius, an approximately flat distribution in stellar mass, and a sample spanning a wide range of environments. Analysis of our prototype observations demonstrates MaNGA's ability to probe gas ionization, shed light on recent star formation and quenching, enable dynamical modeling, decompose constituent components, and map the composition of stellar populations. MaNGA's spatially resolved spectra will enable an unprecedented study of the astrophysics of nearby galaxies in the coming 6 yr.

  20. OVERVIEW OF THE SDSS-IV MaNGA SURVEY: MAPPING NEARBY GALAXIES AT APACHE POINT OBSERVATORY

    Bundy, Kevin; Bershady, Matthew A.; Wake, David A.; Tremonti, Christy; Diamond-Stanic, Aleksandar M.; Law, David R.; Cherinka, Brian; Yan, Renbin; Sánchez-Gallego, José R.; Drory, Niv; MacDonald, Nicholas; Weijmans, Anne-Marie; Thomas, Daniel; Masters, Karen; Coccato, Lodovico; Aragón-Salamanca, Alfonso; Avila-Reese, Vladimir; Badenes, Carles; Falcón-Barroso, Jésus; Belfiore, Francesco

    2015-01-01

    We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. MaNGA will investigate the internal kinematic structure and composition of gas and stars in an unprecedented sample of 10,000 nearby galaxies. We summarize essential characteristics of the instrument and survey design in the context of MaNGA's key science goals and present prototype observations to demonstrate MaNGA's scientific potential. MaNGA employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12'' (19 fibers) to 32'' (127 fibers). Two dual-channel spectrographs provide simultaneous wavelength coverage over 3600-10300 Å at R ∼ 2000. With a typical integration time of 3 hr, MaNGA reaches a target r-band signal-to-noise ratio of 4-8 (Å –1 per 2'' fiber) at 23 AB mag arcsec –2 , which is typical for the outskirts of MaNGA galaxies. Targets are selected with M * ≳ 10 9 M ☉ using SDSS-I redshifts and i-band luminosity to achieve uniform radial coverage in terms of the effective radius, an approximately flat distribution in stellar mass, and a sample spanning a wide range of environments. Analysis of our prototype observations demonstrates MaNGA's ability to probe gas ionization, shed light on recent star formation and quenching, enable dynamical modeling, decompose constituent components, and map the composition of stellar populations. MaNGA's spatially resolved spectra will enable an unprecedented study of the astrophysics of nearby galaxies in the coming 6 yr

  1. SDSS IV MaNGA - sSFR profiles and the slow quenching of discs in green valley galaxies

    Belfiore, Francesco; Maiolino, Roberto; Bundy, Kevin; Masters, Karen; Bershady, Matthew; Oyarzún, Grecco; Lin, Lihwai; Cano-Diaz, Mariana; Wake, David; Spindler, Ashley; Thomas, Daniel; Brownstein, Joel R.; Drory, Niv; Yan, Renbin

    2018-03-01

    We study radial profiles in Hα equivalent width and specific star formation rate (sSFR) derived from spatially-resolved SDSS-IV MaNGA spectroscopy to gain insight on the physical mechanisms that suppress star formation and determine a galaxy's location in the SFR-M_\\star diagram. Even within the star-forming `main sequence', the measured sSFR decreases with stellar mass, both in an integrated and spatially-resolved sense. Flat sSFR radial profiles are observed for log(M_\\star / M_⊙ ) history. Our primary focus is the green valley, constituted by galaxies lying below the star formation main sequence, but not fully passive. In the green valley we find sSFR profiles that are suppressed with respect to star-forming galaxies of the same mass at all galactocentric distances out to 2 effective radii. The responsible quenching mechanism therefore appears to affect the entire galaxy, not simply an expanding central region. The majority of green valley galaxies of log(M_\\star / M_⊙ ) > 10.0 are classified spectroscopically as central low-ionisation emission-line regions (cLIERs). Despite displaying a higher central stellar mass concentration, the sSFR suppression observed in cLIER galaxies is not simply due to the larger mass of the bulge. Drawing a comparison sample of star forming galaxies with the same M_\\star and Σ _{1 kpc} (the mass surface density within 1 kpc), we show that a high Σ _{1 kpc} is not a sufficient condition for determining central quiescence.

  2. Do galaxy global relationships emerge from local ones? The SDSS IV MaNGA surface mass density-metallicity relation

    Barrera-Ballesteros, Jorge K.; Heckman, Timothy M.; Zhu, Guangtun B.; Zakamska, Nadia L.; Sánchez, Sebastian F.; Law, David; Wake, David; Green, Jenny E.; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey; Malanushenko, Elena; Pan, Kaike; Roman Lopes, Alexandre; Lane, Richard R.

    2016-12-01

    We present the stellar surface mass density versus gas metallicity (Σ*-Z) relation for more than 500 000 spatially resolved star-forming resolution elements (spaxels) from a sample of 653 disc galaxies included in the SDSS IV MaNGA survey. We find a tight relation between these local properties, with higher metallicities as the surface density increases. This relation extends over three orders of magnitude in the surface mass density and a factor of 4 in metallicity. We show that this local relationship can simultaneously reproduce two well-known properties of disc galaxies: their global mass-metallicity relationship and their radial metallicity gradients. We also find that the Σ*-Z relation is largely independent of the galaxy's total stellar mass and specific star formation rate (sSFR), except at low stellar mass and high sSFR. These results suggest that in the present-day universe local properties play a key role in determining the gas-phase metallicity in typical disc galaxies.

  3. MASS AND ENVIRONMENT AS DRIVERS OF GALAXY EVOLUTION IN SDSS AND zCOSMOS AND THE ORIGIN OF THE SCHECHTER FUNCTION

    Peng, Ying-Jie; Lilly, Simon J.; Kovac, Katarina; Bolzonella, Micol; Pozzetti, Lucia; Renzini, Alvio; Zamorani, Gianni; Ilbert, Olivier; Knobel, Christian; Iovino, Angela; Maier, Christian; Cucciati, Olga; Tasca, Lidia; Carollo, C. Marcella; Silverman, John; Kampczyk, Pawel; De Ravel, Loic; Sanders, David; Scoville, Nicholas; Contini, Thierry; Mainieri, Vincenzo; Scodeggio, Marco; Kneib, Jean-Paul; Le Fevre, Olivier; Bardelli, Sandro; Bongiorno, Angela; Caputi, Karina; Coppa, Graziano; de la Torre, Sylvain; Franzetti, Paolo; Garilli, Bianca; Lamareille, Fabrice; Le Borgne, Jean-Francois; Le Brun, Vincent; Mignoli, Marco; Montero, Enrique Perez; Pello, Roser; Ricciardelli, Elena; Tanaka, Masayuki; Tresse, Laurence; Vergani, Daniela; Welikala, Niraj; Zucca, Elena; Oesch, Pascal; Abbas, Ummi; Barnes, Luke; Bordoloi, Rongmon; Bottini, Dario; Cappi, Alberto; Cassata, Paolo; Cimatti, Andrea; Fumana, Marco; Hasinger, Gunther; Koekemoer, Anton; Leauthaud, Alexei; Maccagni, Dario; Marinoni, Christian; McCracken, Henry; Memeo, Pierdomenico; Meneux, Baptiste; Nair, Preethi; Porciani, Cristiano; Presotto, Valentina; Scaramella, Roberto

    2010-01-01

    We explore the simple inter-relationships between mass, star formation rate, and environment in the SDSS, zCOSMOS, and other deep surveys. We take a purely empirical approach in identifying those features of galaxy evolution that are demanded by the data and then explore the analytic consequences of

  4. The Cluster Lens SDSS 1004+4112: Constraining World Models With its Multiply-Imaged Quasar and Galaxies

    Kochanek, C.

    2005-07-01

    We will use deep ACS imaging of the giant {15 arcsec} four-image z_s=1.734 lensed quasar SDSS 1004+4112, and its z_l=0.68 lensing galaxy cluster, to identify many additional multiply-imaged background galaxies. Combining the existing single orbit ACS I-band image with ground based data, we have definitely identified two multiply imaged galaxies with estimated redshifts of 2.6 and 4.3, about 15 probable images of background galaxies, and a point source in the core of the central cD galaxy, which is likely to be the faint, fifth image of the quasar. The new data will provide accurate photometric redshifts, confirm that the candidate fifth image has the same spectral energy distribution as the other quasar images, allow secure identification of additional multiply-lensed galaxies for improving the mass model, and permit identification of faint cluster members. Due to the high lens redshift and the broad redshift distribution of the lensed background sources, we should be able to use the source-redshift scaling of the Einstein radius that depends on {d_ls/d_os}, to derive a direct, geometric estimate of Omega_Lambda. The deeper images will also allow a weak lensing analysis to extend the mass distribution to larger radii. Unlike any other cluster lenses, the time delay between the lensed quasar images {already measured for the A-B images, and measurable for the others over the next few years}, breaks the so-called kappa-degeneracies that complicate weak-lensing analyses.

  5. The MASSIVE Survey - V. Spatially resolved stellar angular momentum, velocity dispersion, and higher moments of the 41 most massive local early-type galaxies

    Veale, Melanie; Ma, Chung-Pei; Thomas, Jens; Greene, Jenny E.; McConnell, Nicholas J.; Walsh, Jonelle; Ito, Jennifer; Blakeslee, John P.; Janish, Ryan

    2017-01-01

    We present spatially resolved two-dimensional stellar kinematics for the 41 most massive early-type galaxies (ETGs; MK ≲ -25.7 mag, stellar mass M* ≳ 1011.8 M⊙) of the volume-limited (D McDonald Observatory, covering a 107 arcsec × 107 arcsec field of view (often reaching 2 to 3 effective radii). We measure the 2D spatial distribution of each galaxy's angular momentum (λ and fast or slow rotator status), velocity dispersion (σ), and higher order non-Gaussian velocity features (Gauss-Hermite moments h3 to h6). Our sample contains a high fraction (˜80 per cent) of slow and non-rotators with λ ≲ 0.2. When combined with the lower mass ETGs in the ATLAS3D survey, we find the fraction of slow rotators to increase dramatically with galaxy mass, reaching ˜50 per cent at MK ˜ -25.5 mag and ˜90 per cent at MK ≲ -26 mag. All of our fast rotators show a clear anticorrelation between h3 and V/σ, and the slope of the anticorrelation is steeper in more round galaxies. The radial profiles of σ show a clear luminosity and environmental dependence: the 12 most luminous galaxies in our sample (MK ≲ -26 mag) are all brightest cluster/group galaxies (except NGC 4874) and all have rising or nearly flat σ profiles, whereas five of the seven `isolated' galaxies are all fainter than MK = -25.8 mag and have falling σ. All of our galaxies have positive average h4; the most luminous galaxies have average h4 ˜ 0.05, while less luminous galaxies have a range of values between 0 and 0.05. Most of our galaxies show positive radial gradients in h4, and those galaxies also tend to have rising σ profiles. We discuss the implications for the relationship among dynamical mass, σ, h4, and velocity anisotropy for these massive galaxies.

  6. The stellar initial mass function of early-type galaxies from low to high stellar velocity dispersion: homogeneous analysis of ATLAS3D and Sloan Lens ACS galaxies

    Posacki, Silvia; Cappellari, Michele; Treu, Tommaso; Pellegrini, Silvia; Ciotti, Luca

    2015-01-01

    We present an investigation about the shape of the initial mass function (IMF) of early-type galaxies (ETGs), based on a joint lensing and dynamical analysis, and on stellar population synthesis models, for a sample of 55 lens ETGs identified by the Sloan Lens Advanced Camera for Surveys (SLACS). We construct axisymmetric dynamical models based on the Jeans equations which allow for orbital anisotropy and include a dark matter halo. The models reproduce in detail the observed Hubble Space Telescope photometry and are constrained by the total projected mass within the Einstein radius and the stellar velocity dispersion (σ) within the Sloan Digital Sky Survey fibres. Comparing the dynamically-derived stellar mass-to-light ratios (M*/L)dyn, obtained for an assumed halo slope ρh ∝ r-1, to the stellar population ones (M*/L)Salp, derived from full-spectrum fitting and assuming a Salpeter IMF, we infer the mass normalization of the IMF. Our results confirm the previous analysis by the SLACS team that the mass normalization of the IMF of high-σ galaxies is consistent on average with a Salpeter slope. Our study allows for a fully consistent study of the trend between IMF and σ for both the SLACS and atlas3D samples, which explore quite different σ ranges. The two samples are highly complementary, the first being essentially σ selected, and the latter volume-limited and nearly mass selected. We find that the two samples merge smoothly into a single trend of the form log α = (0.38 ± 0.04) × log (σe/200 km s-1) + ( - 0.06 ± 0.01), where α = (M*/L)dyn/(M*/L)Salp and σe is the luminosity averaged σ within one effective radius Re. This is consistent with a systematic variation of the IMF normalization from Kroupa to Salpeter in the interval σe ≈ 90-270 km s-1.

  7. EARLY-TYPE GALAXIES AT z = 1.3. I. THE LYNX SUPERCLUSTER: CLUSTER AND GROUPS AT z = 1.3. MORPHOLOGY AND COLOR-MAGNITUDE RELATION

    Mei, Simona; Raichoor, Anand; Huertas-Company, Marc; Adam Stanford, S.; Rettura, Alessandro; Jee, Myungkook J.; Holden, Brad P.; Illingworth, Garth D.; Postman, Marc; Nakata, Fumiaki; Kodama, Tadayuki; Finoguenov, Alexis; Ford, Holland C.; Rosati, Piero; Tanaka, Masayuki; Koyama, Yusei; Shankar, Francesco; Carrasco, Eleazar R.; Demarco, Ricardo; Eisenhardt, Peter

    2012-01-01

    We confirm the detection of three groups in the Lynx supercluster, at z ≈ 1.3, through spectroscopic follow-up and X-ray imaging, and we give estimates for their redshifts and masses. We study the properties of the group galaxies compared to the two central clusters, RX J0849+4452 and RX J0848+4453. Using spectroscopic follow-up and multi-wavelength photometric redshifts, we select 89 galaxies in the clusters, of which 41 are spectroscopically confirmed, and 74 galaxies in the groups, of which 25 are spectroscopically confirmed. We morphologically classify galaxies by visual inspection, noting that our early-type galaxy (ETG) sample would have been contaminated at the 30%-40% level by simple automated classification methods (e.g., based on Sérsic index). In luminosity-selected samples, both clusters and groups show high fractions of bulge-dominated galaxies with a diffuse component that we visually identified as a disk and which we classified as bulge-dominated spirals, e.g., Sas. The ETG fractions never rise above ≈50% in the clusters, which is low compared to the fractions observed in other massive clusters at z ≈ 1. In the groups, ETG fractions never exceed ≈25%. However, overall bulge-dominated galaxy fractions (ETG plus Sas) are similar to those observed for ETGs in clusters at z ∼ 1. Bulge-dominated galaxies visually classified as spirals might also be ETGs with tidal features or merger remnants. They are mainly red and passive, and span a large range in luminosity. Their star formation seems to have been quenched before experiencing a morphological transformation. Because their fraction is smaller at lower redshifts, they might be the spiral population that evolves into ETGs. For mass-selected samples of galaxies with masses M > 10 10.6 M ☉ within Σ > 500 Mpc –2 , the ETG and overall bulge-dominated galaxy fractions show no significant evolution with respect to local clusters, suggesting that morphological transformations might occur at lower

  8. Galaxy Zoo: dust in spiral galaxies star

    Masters, Karen L.; Nichol, Robert; Bamford, Steven; Mosleh, Moein; Lintott, Chris J.; Andreescu, Dan; Edmondson, Edward M.; Keel, William C.; Murray, Phil; Raddick, M. Jordan; Schawinski, Kevin; Slosar, Anze; Szalay, Alexander S.; Thomas, Daniel; Vandenberg, Jan

    2010-01-01

    We investigate the effect of dust on spiral galaxies by measuring the inclination dependence of optical colours for 24 276 well-resolved Sloan Digital Sky Survey (SDSS) galaxies visually classified via the Galaxy Zoo project. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4 mag for the ugri passbands (estimating 0.3 mag of extinction in z band). We split the sample into ‘bulgy’ (early-type) and ‘discy’ (late-typ...

  9. A TALE OF A RICH CLUSTER AT z ∼ 0.8 AS SEEN BY THE STAR FORMATION HISTORIES OF ITS EARLY-TYPE GALAXIES

    Ferré-Mateu, Anna [Subaru Telescope, Hilo, HI 96720 (United States); Sánchez-Blázquez, Patricia [Departamento de Física Teórica, Universidad Autónoma de Madrid, E-28049 Cantoblanco, Madrid (Spain); Vazdekis, Alexandre; De la Rosa, Ignacio G., E-mail: aferre@naoj.org [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)

    2014-12-20

    We present a detailed stellar population analysis for a sample of 24 early-type galaxies (ETGs) belonging to the rich cluster RX J0152.7-1357 at z = 0.83. We have derived the age, metallicity, abundance pattern, and star formation history (SFH) for each galaxy individually to further characterize this intermediate-z reference cluster. We then study how these stellar population parameters depend on the local environment. This provides a better understanding on the formation timescales and subsequent evolution of the substructures in this cluster. We have also explored the evolutionary link between z ∼ 0.8 ETGs and those in the local universe by comparing the trends that the stellar population parameters followed with galaxy velocity dispersion at each epoch. We find that the ETGs in Coma are consistent with being the (passively evolving) descendants of the ETG population in RX J10152.7-1357. Furthermore, our results favor a downsizing picture, where the subclumps centers were formed first. These central parts contain the most massive galaxies, which formed the bulk of their stars in a short, burst-like event at high z. On the contrary, the cluster outskirts are populated with less-massive, smaller galaxies that show a wider variety of SFHs. In general, they present extended star formation episodes over cosmic time, which seems to be related to their posterior incorporation into the cluster around 4 Gyr after the initial event of formation.

  10. Distant clusters of galaxies in the 2XMM/SDSS footprint: follow-up observations with the LBT

    Rabitz, A.; Lamer, G.; Schwope, A.; Takey, A.

    2017-11-01

    Context. Galaxy clusters at high redshift are important to test cosmological models and models for the growth of structure. They are difficult to find in wide-angle optical surveys, however, leaving dedicated follow-up of X-ray selected candidates as one promising identification route. Aims: We aim to increase the number of galaxy clusters beyond the SDSS-limit, z 0.75. Methods: We compiled a list of extended X-ray sources from the 2XMMp catalogue within the footprint of the Sloan Digital Sky Survey. Fields without optical counterpart were selected for further investigation. Deep optical imaging and follow-up spectroscopy were obtained with the Large Binocular Telescope, Arizona (LBT), of those candidates not known to the literature. Results: From initially 19 candidates, selected by visually screening X-ray images of 478 XMM-Newton observations and the corresponding SDSS images, 6 clusters were found in the literature. Imaging data through r,z filters were obtained for the remaining candidates, and 7 were chosen for multi-object (MOS) spectroscopy. Spectroscopic redshifts, optical magnitudes, and X-ray parameters (flux, temperature, and luminosity) are presented for the clusters with spectroscopic redshifts. The distant clusters studied here constitute one additional redshift bin for studies of the LX-T relation, which does not seem to evolve from high to low redshifts. Conclusions: The selection method of distant galaxy clusters presented here was highly successful. It is based solely on archival optical (SDSS) and X-ray (XMM-Newton) data. Out of 19 selected candidates, 6 of the 7 candidates selected for spectroscopic follow-up were verified as distant clusters, a further candidate is most likely a group of galaxies at z 1.21. Out of the remaining 12 candidates, 6 were known previously as galaxy clusters, one object is a likely X-ray emission from an AGN radio jet, and for 5 we see no clear evidence for them to be high-redshift galaxy clusters. Based on

  11. A Uniformly Selected Sample of Low-mass Black Holes in Seyfert 1 Galaxies. II. The SDSS DR7 Sample

    Liu, He-Yang; Yuan, Weimin; Dong, Xiao-Bo; Zhou, Hongyan; Liu, Wen-Juan

    2018-04-01

    A new sample of 204 low-mass black holes (LMBHs) in active galactic nuclei (AGNs) is presented with black hole masses in the range of (1–20) × 105 M ⊙. The AGNs are selected through a systematic search among galaxies in the Seventh Data Release (DR7) of the Sloan Digital Sky Survey (SDSS), and careful analyses of their optical spectra and precise measurement of spectral parameters. Combining them with our previous sample selected from SDSS DR4 makes it the largest LMBH sample so far, totaling over 500 objects. Some of the statistical properties of the combined LMBH AGN sample are briefly discussed in the context of exploring the low-mass end of the AGN population. Their X-ray luminosities follow the extension of the previously known correlation with the [O III] luminosity. The effective optical-to-X-ray spectral indices α OX, albeit with a large scatter, are broadly consistent with the extension of the relation with the near-UV luminosity L 2500 Å. Interestingly, a correlation of α OX with black hole mass is also found, with α OX being statistically flatter (stronger X-ray relative to optical) for lower black hole masses. Only 26 objects, mostly radio loud, were detected in radio at 20 cm in the FIRST survey, giving a radio-loud fraction of 4%. The host galaxies of LMBHs have stellar masses in the range of 108.8–1012.4 M ⊙ and optical colors typical of Sbc spirals. They are dominated by young stellar populations that seem to have undergone continuous star formation history.

  12. The ALHAMBRA survey: 2D analysis of the stellar populations in massive early-type galaxies at z < 0.3

    San Roman, I.; Cenarro, A. J.; Díaz-García, L. A.; López-Sanjuan, C.; Varela, J.; González Delgado, R. M.; Sánchez-Blázquez, P.; Alfaro, E. J.; Ascaso, B.; Bonoli, S.; Borlaff, A.; Castander, F. J.; Cerviño, M.; Fernández-Soto, A.; Márquez, I.; Masegosa, J.; Muniesa, D.; Pović, M.; Viironen, K.; Aguerri, J. A. L.; Benítez, N.; Broadhurst, T.; Cabrera-Caño, J.; Cepa, J.; Cristóbal-Hornillos, D.; Infante, L.; Martínez, V. J.; Moles, M.; del Olmo, A.; Perea, J.; Prada, F.; Quintana, J. M.

    2018-01-01

    We present a technique that permits the analysis of stellar population gradients in a relatively low-cost way compared to integral field unit (IFU) surveys. We developed a technique to analyze unresolved stellar populations of spatially resolved galaxies based on photometric multi-filter surveys. This technique allows the analysis of vastly larger samples and out to larger galactic radii. We derived spatially resolved stellar population properties and radial gradients by applying a centroidal Voronoi tessellation and performing a multicolor photometry spectral energy distribution fitting. This technique has been successfully applied to a sample of 29 massive (M⋆ > 1010.5M⊙) early-type galaxies at z Max-Planck-Institut für Astronomie (MPIA) at Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC).

  13. GEOMETRY OF STAR-FORMING GALAXIES FROM SDSS, 3D-HST, AND CANDELS

    Van der Wel, A.; Chang, Yu-Yen; Rix, H.-W.; Martig, M.; Bell, E. F.; Holden, B. P.; Koo, D. C.; Mozena, M.; Faber, S. M.; Ferguson, H. C.; Brammer, G.; Kassin, S. A.; Giavalisco, M.; Skelton, R.; Whitaker, K.; Momcheva, I.; Van Dokkum, P. G.; Dekel, A.; Ceverino, D.; Franx, M.

    2014-01-01

    We determine the intrinsic, three-dimensional shape distribution of star-forming galaxies at 0 < z < 2.5, as inferred from their observed projected axis ratios. In the present-day universe, star-forming galaxies of all masses 10 9 -10 11 M ☉ are predominantly thin, nearly oblate disks, in line with previous studies. We now extend this to higher redshifts, and find that among massive galaxies (M * > 10 10 M ☉ ) disks are the most common geometric shape at all z ≲ 2. Lower-mass galaxies at z > 1 possess a broad range of geometric shapes: the fraction of elongated (prolate) galaxies increases toward higher redshifts and lower masses. Galaxies with stellar mass 10 9 M ☉ (10 10 M ☉ ) are a mix of roughly equal numbers of elongated and disk galaxies at z ∼ 1 (z ∼ 2). This suggests that galaxies in this mass range do not yet have disks that are sustained over many orbital periods, implying that galaxies with present-day stellar mass comparable to that of the Milky Way typically first formed such sustained stellar disks at redshift z ∼ 1.5-2. Combined with constraints on the evolution of the star formation rate density and the distribution of star formation over galaxies with different masses, our findings imply that, averaged over cosmic time, the majority of stars formed in disks

  14. THE SL2S GALAXY-SCALE LENS SAMPLE. IV. THE DEPENDENCE OF THE TOTAL MASS DENSITY PROFILE OF EARLY-TYPE GALAXIES ON REDSHIFT, STELLAR MASS, AND SIZE

    Sonnenfeld, Alessandro; Treu, Tommaso; Suyu, Sherry H.; Gavazzi, Raphaël; Marshall, Philip J.; Auger, Matthew W.; Nipoti, Carlo

    2013-01-01

    We present optical and near-infrared spectroscopy obtained at Keck, Very Large Telescope, and Gemini for a sample of 36 secure strong gravitational lens systems and 17 candidates identified as part of the Strong Lensing Legacy Survey. The deflectors are massive early-type galaxies in the redshift range z d = 0.2-0.8, while the lensed sources are at z s = 1-3.5. We combine these data with photometric and lensing measurements presented in the companion paper III and with lenses from the Sloan Lens Advanced Camera for Surveys and Lènses Structure and Dynamics surveys to investigate the cosmic evolution of the internal structure of massive early-type galaxies over half the age of the universe. We study the dependence of the slope of the total mass density profile, γ' (ρ(r)∝r -γ ' ), on stellar mass, size, and redshift. We find that two parameters are sufficient to determine γ' with less than 6% residual scatter. At fixed redshift, γ' depends solely on the surface stellar mass density ∂γ'/∂Σ * = 0.38 ± 0.07, i.e., galaxies with denser stars also have steeper slopes. At fixed M * and R eff , γ' depends on redshift, in the sense that galaxies at a lower redshift have steeper slopes (∂γ'/∂z = –0.31 ± 0.10). However, the mean redshift evolution of γ' for an individual galaxy is consistent with zero dγ'/dz = –0.10 ± 0.12. This result is obtained by combining our measured dependencies of γ' on z, M * ,R eff with the evolution of the R eff -M * taken from the literature, and is broadly consistent with current models of the formation and evolution of massive early-type galaxies. Detailed quantitative comparisons of our results with theory will provide qualitatively new information on the detailed physical processes at work

  15. SDSS J211852.96-073227.5: a new γ-ray flaring narrow-line Seyfert 1 galaxy

    Yang, Hui; Yuan, Weimin; Yao, Su; Li, Ye; Zhang, Jin; Zhou, Hongyan; Komossa, S.; Liu, He-Yang; Jin, Chichuan

    2018-04-01

    We report on the identification of a new γ-ray-emitting narrow-line Seyfert 1 (NLS1) galaxy, SDSS J211852.96-073227.5 (hereafter J2118-0732). The galaxy, at a redshift of 0.26, is associated with a radio source of flat/inverted spectrum at high radio frequencies. The analysis of its optical spectrum obtained in the Sloan Digital Sky Survey revealed a small linewidth of the broad component of the Hβ line (FWHM = 1585 km s-1), making it a radio-loud NLS1 galaxy - an intriguing class of active galactic nuclei with exceptional multi-wavelength properties. A new γ-ray source centred at J2118-0732 was sporadically detected during 2009-2013 in form of flares by the Fermi-LAT. Our XMM-Newton observations revealed a flat X-ray spectrum described by a simple power law, and a flux variation by a factor of ˜2.5 in 5 months. The source also shows intraday variability in the infrared band. Its broad-band spectral energy distribution can be modelled by emission from a simple one-zone leptonic jet model, and the flux drop from infrared to X-rays in five months can be explained by changes of the jet parameters, though the exact values may be subject to relatively large uncertainties. With the NLS1-blazar composite nucleus, the clear detection of the host galaxy and the synchronous variations in the multi-wavelength fluxes, J2118-0732 provides a new perspective on the formation and evolution of relativistic jets under the regime of relatively small black hole masses and high accretion rates.

  16. Spectral properties of the narrow-line region in Seyfert galaxies selected from the SDSS-DR7

    Vaona, L.; Ciroi, S.; Di Mille, F.; Cracco, V.; La Mura, G.; Rafanelli, P.

    2012-12-01

    Although the properties of the narrow-line region (NLR) of active galactic nuclei (AGN) have been deeply studied by many authors in the past three decades, many questions are still open. The main goal of this work is to explore the NLR of Seyfert galaxies by collecting a large statistical spectroscopic sample of Seyfert 2 and Intermediate-type Seyfert galaxies having a high signal-to-noise ratio in order to take advantage of a high number of emission lines to be accurately measured. 2153 Seyfert 2 and 521 Intermediate-type Seyfert spectra were selected from Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) with a diagnostic diagram based on the oxygen emission-line ratios. All the emission lines, broad components included, were measured by means of a self-developed code, after the subtraction of the stellar component. Physical parameters, such as internal reddening, ionization parameter, temperature, density, gas and stellar velocity dispersion were determined for each object. Furthermore, we estimated mass and radius of the NLR, kinetic energy of the ionized gas and black hole accretion rate. From the emission-line analysis and the estimated physical properties, it appears that the NLR is similar in Seyfert 2 and Intermediate-Seyfert galaxies. The only differences, lower extinction, gas kinematics in general not dominated by the host galaxy gravitational potential and higher percentage of [O III]λ5007 blue asymmetries in Intermediate-Seyfert, can be ascribed to an effect of inclination of our line of sight with respect to the torus axis.

  17. SDSS IV MaNGA: Discovery of an Hα Blob Associated with a Dry Galaxy Pair—Ejected Gas or a “Dark” Galaxy Candidate?

    Lin, Lihwai; Lin, Jing-Hua; Hsu, Chin-Hao; Fu, Hai; Huang, Song; Sánchez, Sebastián F.; Gwyn, Stephen; Gelfand, Joseph D.; Cheung, Edmond; Masters, Karen; Peirani, Sébastien; Rujopakarn, Wiphu; Stark, David V.; Belfiore, Francesco; Bothwell, M. S.; Bundy, Kevin; Hagen, Alex; Hao, Lei; Huang, Shan; Law, David; Li, Cheng; Lintott, Chris; Maiolino, Roberto; Roman-Lopes, Alexandre; Wang, Wei-Hao; Xiao, Ting; Yuan, Fangting; Bizyaev, Dmitry; Malanushenko, Elena; Drory, Niv; Fernández-Trincado, J. G.; Pace, Zach; Pan, Kaike; Thomas, Daniel

    2017-03-01

    We report the discovery of a mysterious giant Hα blob that is ˜8 kpc away from the main MaNGA target 1-24145, one component of a dry galaxy merger, and has been identified in the first-year SDSS-IV MaNGA data. The size of the Hα blob is ˜3-4 kpc in radius, and the Hα distribution is centrally concentrated. However, there is no optical continuum counterpart in the deep broadband images reaching ˜26.9 mag arcsec-2 in surface brightness. We estimate that the masses of the ionized and cold gases are 3.3× {10}5 {M}⊙ and MaNGA 1-24145 to the Hα blob, suggesting that the primary ionizing source may come from MaNGA 1-24145, likely a low-activity AGN. Possible explanations for this Hα blob include the AGN outflow, the gas remnant being tidally or ram-pressure stripped from MaNGA 1-24145, or an extremely low surface brightness galaxy. However, the stripping scenario is less favored according to galaxy merger simulations and the morphology of the Hα blob. With the current data, we cannot distinguish whether this Hα blob is ejected gas due to a past AGN outburst, or a special category of “ultra-diffuse galaxy” interacting with MaNGA 1-24145 that further induces the gas inflow to fuel the AGN in MaNGA 1-24145.

  18. Stellar kinematics and structural properties of virgo cluster dwarf early-type galaxies from the SMAKCED project. I. Kinematically decoupled cores and implications for infallen groups in clusters

    Toloba, E.; Guhathakurta, P. [UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Van de Ven, G. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Boissier, S.; Boselli, A. [Laboratoire d' Astrophysique de Marseille-LAM, Université d' Aix-Marseille and CNRS, UMR 7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Den Brok, M. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Falcón-Barroso, J.; Ryś, A. [Instituto de Astrofísica de Canarias, Vía Láctea s/n, La Laguna, Tenerife (Spain); Hensler, G. [Department of Astrophysics, University of Vienna, Türkenschanzstraße 17, 1180 Vienna (Austria); Janz, J.; Lisker, T. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg (Germany); Laurikainen, E.; Salo, H. [Division of Astronomy, Department of Physics, University of Oulu, P.O. Box 3000, FI-90014 Oulu (Finland); Paudel, S. [Laboratoire AIM Paris-Saclay, CNRS/INSU, Université Paris Diderot, CEA/IRFU/SAp, F-91191 Gif-sur-Yvette Cedex (France); Peletier, R. F., E-mail: toloba@ucolick.org [Kapteyn Astronomical Institute, Postbus 800, 9700 AV Groningen (Netherlands)

    2014-03-10

    We present evidence for kinematically decoupled cores (KDCs) in two dwarf early-type (dE) galaxies in the Virgo cluster, VCC 1183 and VCC 1453, studied as part of the SMAKCED stellar absorption-line spectroscopy and imaging survey. These KDCs have radii of 1.''8 (0.14 kpc) and 4.''2 (0.33 kpc), respectively. Each of these KDCs is distinct from the main body of its host galaxy in two ways: (1) inverted sense of rotation and (2) younger (and possibly more metal-rich) stellar population. The observed stellar population differences are probably associated with the KDC, although we cannot rule out the possibility of intrinsic radial gradients in the host galaxy. We describe a statistical analysis method to detect, quantify the significance of, and characterize KDCs in long-slit rotation curve data. We apply this method to the two dE galaxies presented in this paper and to five other dEs for which KDCs have been reported in the literature. Among these seven dEs, there are four significant KDC detections, two marginal KDC detections, and one dE with an unusual central kinematic anomaly that may be an asymmetric KDC. The frequency of occurrence of KDCs and their properties provide important constraints on the formation history of their host galaxies. We discuss different formation scenarios for these KDCs in cluster environments and find that dwarf-dwarf wet mergers or gas accretion can explain the properties of these KDCs. Both of these mechanisms require that the progenitor had a close companion with a low relative velocity. This suggests that KDCs were formed in galaxy pairs residing in a poor group environment or in isolation whose subsequent infall into the cluster quenched star formation.

  19. Evidence of a Bottom-heavy Initial Mass Function in Massive Early-type Galaxies from Near-infrared Metal Lines

    Lagattuta, David J.; Mould, Jeremy R.; Forbes, Duncan A.; Monson, Andrew J.; Pastorello, Nicola; Persson, S. Eric

    2017-09-01

    We present new evidence for a variable stellar initial mass function (IMF) in massive early-type galaxies, using high-resolution, near-infrared spectroscopy from the Folded-port InfraRed Echellette spectrograph (FIRE) on the Magellan Baade Telescope at Las Campanas Observatory. In this pilot study, we observe several gravity-sensitive metal lines between 1.1 and 1.3 μm in eight highly luminous (L˜ 10{L}* ) nearby galaxies. Thanks to the broad wavelength coverage of FIRE, we are also able to observe the Ca II triplet feature, which helps with our analysis. After measuring the equivalent widths (EWs) of these lines, we notice mild to moderate trends between EW and central velocity dispersion (σ), with some species (K I, Na I, Mn I) showing a positive EW-σ correlation and others (Mg I, Ca II, Fe I) a negative one. To minimize the effects of metallicity, we measure the ratio R = [EW(K I)/EW(Mg I)], finding a significant systematic increase in this ratio with respect to σ. We then probe for variations in the IMF by comparing the measured line ratios to the values expected in several IMF models. Overall, we find that low-mass galaxies (σ ˜ 100 km s-1) favor a Chabrier IMF, while high-mass galaxies (σ ˜ 350 km s-1) are better described with a steeper (dwarf-rich) IMF slope. While we note that our galaxy sample is small and may suffer from selection effects, these initial results are still promising. A larger sample of galaxies will therefore provide an even clearer picture of IMF trends in this regime. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  20. Astrophysics. Multiple images of a highly magnified supernova formed by an early-type cluster galaxy lens.

    Kelly, Patrick L; Rodney, Steven A; Treu, Tommaso; Foley, Ryan J; Brammer, Gabriel; Schmidt, Kasper B; Zitrin, Adi; Sonnenfeld, Alessandro; Strolger, Louis-Gregory; Graur, Or; Filippenko, Alexei V; Jha, Saurabh W; Riess, Adam G; Bradac, Marusa; Weiner, Benjamin J; Scolnic, Daniel; Malkan, Matthew A; von der Linden, Anja; Trenti, Michele; Hjorth, Jens; Gavazzi, Raphael; Fontana, Adriano; Merten, Julian C; McCully, Curtis; Jones, Tucker; Postman, Marc; Dressler, Alan; Patel, Brandon; Cenko, S Bradley; Graham, Melissa L; Tucker, Bradley E

    2015-03-06

    In 1964, Refsdal hypothesized that a supernova whose light traversed multiple paths around a strong gravitational lens could be used to measure the rate of cosmic expansion. We report the discovery of such a system. In Hubble Space Telescope imaging, we have found four images of a single supernova forming an Einstein cross configuration around a redshift z = 0.54 elliptical galaxy in the MACS J1149.6+2223 cluster. The cluster's gravitational potential also creates multiple images of the z = 1.49 spiral supernova host galaxy, and a future appearance of the supernova elsewhere in the cluster field is expected. The magnifications and staggered arrivals of the supernova images probe the cosmic expansion rate, as well as the distribution of matter in the galaxy and cluster lenses. Copyright © 2015, American Association for the Advancement of Science.

  1. VizieR Online Data Catalog: Tully-Fisher relation for SDSS galaxies (Reyes+, 2011)

    Reyes, R.; Mandelbaum, R.; Gunn, J. E.; Pizagno, J.; Lackner, C. N.

    In this paper, we derive scaling relations between photometric observable quantities and disc galaxy rotation velocity Vrot or Tully-Fisher relations (TFRs). Our methodology is dictated by our purpose of obtaining purely photometric, minimal-scatter estimators of Vrot applicable to large galaxy

  2. SDSS-IV MaNGA: properties of galaxies with kinematically decoupled stellar and gaseous components

    Jin, Yifei; Chen, Yanmei; Shi, Yong; Tremonti, C. A.; Bershady, M. A.; Merrifield, M.; Emsellem, E.; Fu, Hai; Wake, D.; Bundy, K.; Lin, Lihwai; Argudo-Fernandez, M.; Huang, Song; Stark, D. V.; Storchi-Bergmann, T.; Bizyaev, D.; Brownstein, J.; Chisholm, J.; Guo, Qi; Hao, Lei; Hu, Jian; Li, Cheng; Li, Ran; Masters, K. L.; Malanushenko, E.; Pan, Kaike; Riffel, R. A.; Roman-Lopes, A.; Simmons, A.; Thomas, D.; Wang, Lan; Westfall, K.; Yan, Renbin

    2016-11-01

    We study the properties of 66 galaxies with kinematically misaligned gas and stars from MaNGA survey. The fraction of kinematically misaligned galaxies varies with galaxy physical parameters, I.e. M*, SFR and sSFR. According to their sSFR, we further classify these 66 galaxies into three categories, 10 star-forming, 26 `Green Valley' and 30 quiescent ones. The properties of different types of kinematically misaligned galaxies are different in that the star-forming ones have positive gradient in Dn4000 and higher gas-phase metallicity, while the green valley/quiescent ones have negative Dn4000 gradients and lower gas-phase metallicity on average. There is evidence that all types of the kinematically misaligned galaxies tend to live in more isolated environment. Based on all these observational results, we propose a scenario for the formation of star-forming galaxies with kinematically misaligned gas and stars - the progenitor accretes misaligned gas from a gas-rich dwarf or cosmic web, the cancellation of angular momentum from gas-gas collisions between the pre-existing gas and the accreted gas largely accelerates gas inflow, leading to fast centrally concentrated star formation. The higher metallicity is due to enrichment from this star formation. For the kinematically misaligned green valley and quiescent galaxies, they might be formed through gas-poor progenitors accreting kinematically misaligned gas from satellites which are smaller in mass.

  3. SDSS IV MaNGA - spatially resolved diagnostic diagrams: a proof that many galaxies are LIERs

    Belfiore, Francesco; Maiolino, Roberto; Maraston, Claudia; Emsellem, Eric; Bershady, Matthew A.; Masters, Karen L.; Yan, Renbin; Bizyaev, Dmitry; Boquien, Médéric; Brownstein, Joel R.; Bundy, Kevin; Drory, Niv; Heckman, Timothy M.; Law, David R.; Roman-Lopes, Alexandre; Pan, Kaike; Stanghellini, Letizia; Thomas, Daniel; Weijmans, Anne-Marie; Westfall, Kyle B.

    2016-09-01

    We study the spatially resolved excitation properties of the ionized gas in a sample of 646 galaxies using integral field spectroscopy data from the Sloan Digital Sky Survey IV Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) programme. Making use of Baldwin-Philips-Terlevich diagnostic diagrams we demonstrate the ubiquitous presence of extended (kpc scale) low-ionization emission-line regions (LIERs) in both star-forming and quiescent galaxies. In star-forming galaxies LIER emission can be associated with diffuse ionized gas, most evident as extraplanar emission in edge-on systems. In addition, we identify two main classes of galaxies displaying LIER emission: `central LIER' (cLIER) galaxies, where central LIER emission is spatially extended, but accompanied by star formation at larger galactocentric distances, and `extended LIER' (eLIER) galaxies, where LIER emission is extended throughout the whole galaxy. In eLIER and cLIER galaxies, LIER emission is associated with radially flat, low H α equivalent width of line emission (<3 Å) and stellar population indices demonstrating the lack of young stellar populations, implying that line emission follows tightly the continuum due to the underlying old stellar population. The H α surface brightness radial profiles are always shallower than 1/r2 and the line ratio [O III] λ5007/[O II] λλ3727,29 (a tracer of the ionization parameter of the gas) shows a flat gradient. This combined evidence strongly supports the scenario in which LIER emission is not due to a central point source but to diffuse stellar sources, the most likely candidates being hot, evolved (post-asymptotic giant branch) stars. Shocks are observed to play a significant role in the ionization of the gas only in rare merging and interacting systems.

  4. A 30 kpc CHAIN OF ''BEADS ON A STRING'' STAR FORMATION BETWEEN TWO MERGING EARLY TYPE GALAXIES IN THE CORE OF A STRONG-LENSING GALAXY CLUSTER

    Tremblay, Grant R.; Davis, Timothy A. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Gladders, Michael D.; Florian, Michael [Department of Astronomy and Astrophysics and Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Baum, Stefi A.; O' Dea, Christopher P.; Cooke, Kevin C. [Chester F. Carlson Center for Imaging Science and School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States); Bayliss, Matthew B. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Dahle, Håkon [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, N-0315 Oslo (Norway); Rigby, Jane R. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Sharon, Keren [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Soto, Emmaris [Department of Physics, The Catholic University of America, 200 Hannan Hall, Washington, DC 20064 (United States); Wuyts, Eva, E-mail: grant.tremblay@eso.org [Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstr., D-85741 Garching bei München (Germany)

    2014-08-01

    New Hubble Space Telescope ultraviolet and optical imaging of the strong-lensing galaxy cluster SDSS J1531+3414 (z = 0.335) reveals two centrally dominant elliptical galaxies participating in an ongoing major merger. The interaction is at least somewhat rich in cool gas, as the merger is associated with a complex network of 19 massive superclusters of young stars (or small tidal dwarf galaxies) separated by ∼1 kpc in projection from one another, combining to an estimated total star formation rate of ∼5 M {sub ☉} yr{sup –1}. The resolved young stellar superclusters are threaded by narrow Hα, [O II], and blue excess filaments arranged in a network spanning ∼27 kpc across the two merging galaxies. This morphology is strongly reminiscent of the well-known ''beads on a string'' mode of star formation observed on kiloparsec scales in the arms of spiral galaxies, resonance rings, and in tidal tails between interacting galaxies. Nevertheless, the arrangement of this star formation relative to the nuclei of the two galaxies is difficult to interpret in a dynamical sense, as no known ''beads on a string'' systems associated with kiloparsec-scale tidal interactions exhibit such lopsided morphology relative to the merger participants. In this Letter, we present the images and follow-up spectroscopy and discuss possible physical interpretations for the unique arrangement of the young stellar clusters. While we suggest that this morphology is likely to be dynamically short-lived, a more quantitative understanding awaits necessary multiwavelength follow-up, including optical integral field spectroscopy, ALMA submillimeter interferometry, and Chandra X-ray imaging.

  5. THE EFFECT OF SECOND-GENERATION POPULATIONS ON THE INTEGRATED COLORS OF METAL-RICH GLOBULAR CLUSTERS IN EARLY-TYPE GALAXIES

    Chung, Chul; Lee, Sang-Yoon; Yoon, Suk-Jin; Lee, Young-Wook

    2013-01-01

    The mean color of globular clusters (GCs) in early-type galaxies is in general bluer than the integrated color of halo field stars in host galaxies. Metal-rich GCs often appear more associated with field stars than metal-poor GCs, yet show bluer colors than their host galaxy light. Motivated by the discovery of multiple stellar populations in Milky Way GCs, we present a new scenario in which the presence of second-generation (SG) stars in GCs is responsible for the color discrepancy between metal-rich GCs and field stars. The model assumes that the SG populations have an enhanced helium abundance as evidenced by observations, and it gives a good explanation of the bluer optical colors of metal-rich GCs than field stars as well as strong Balmer lines and blue UV colors of metal-rich GCs. Ours may be complementary to the recent scenario suggesting the difference in stellar mass functions (MFs) as an origin for the GC-to-star color offset. A quantitative comparison is given between the SG and MF models.

  6. SDSS-IV MaNGA: constraints on the conditions for star formation in galaxy discs

    Stark, David V.; Bundy, Kevin A.; Orr, Matthew E.; Hopkins, Philip F.; Westfall, Kyle; Bershady, Matthew; Li, Cheng; Bizyaev, Dmitry; Masters, Karen L.; Weijmans, Anne-Marie; Lacerna, Ivan; Thomas, Daniel; Drory, Niv; Yan, Renbin; Zhang, Kai

    2018-02-01

    Regions of disc galaxies with widespread star formation tend to be both gravitationally unstable and self-shielded against ionizing radiation, whereas extended outer discs with little or no star formation tend to be stable and unshielded on average. We explore what drives the transition between these two regimes, specifically whether discs first meet the conditions for self-shielding (parametrized by dust optical depth, τ) or gravitational instability (parametrized by a modified version of Toomre's instability parameters, Qthermal, which quantifies the stability of a gas disc that is thermally supported at T = 104 K). We first introduce a new metric formed by the product of these quantities, Qthermalτ, which indicates whether the conditions for disc instability or self-shielding are easier to meet in a given region of a galaxy, and we discuss how Qthermalτ can be constrained even in the absence of direct gas information. We then analyse a sample of 13 galaxies with resolved gas measurements and find that on average galaxies will reach the threshold for disc instabilities (Qthermal 1). Using integral field spectroscopic observations of a sample of 236 galaxies from the Mapping Nearby Galaxies at APO (MaNGA) survey, we find that the value of Qthermalτ in star-forming discs is consistent with similar behaviour. These results support a scenario where disc fragmentation and collapse occurs before self-shielding, suggesting that gravitational instabilities are the primary condition for widespread star formation in galaxy discs. Our results support similar conclusions based on recent galaxy simulations.

  7. Optical colours of AGN in the Extended Chandra Deep Field South: Obscured black holes in early type galaxies

    Rovilos, E.; Georgantopoulos, I.

    2007-01-01

    We investigate the optical colours of X-ray sources from the Extended Chandra Deep Field South (ECDFS) using photometry from the COMBO-17 survey, aiming to explore AGN - galaxy feedback models. The X-ray sources populate both the ``blue'' and the ``red sequence'' on the colour-magnitude diagram. However, sources in the ``red sequence'' appear systematically more obscured. HST imaging from the GEMS survey demonstrates that the nucleus does not affect significantly the observed colours, and the...

  8. DEEP CHANDRA OBSERVATIONS OF NGC 1404: CLUSTER PLASMA PHYSICS REVEALED BY AN INFALLING EARLY-TYPE GALAXY

    Su, Yuanyuan; Kraft, Ralph P.; Nulsen, Paul; Forman, William R.; Randall, Scott W.; Jones, Christine; Machacek, Marie E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Roediger, Elke [E.A. Milne Centre for Astrophysics, Department of Physics and Mathematics, University of Hull, Hull, HU6 7RX (United Kingdom); Churazov, Eugene, E-mail: yuanyuan.su@cfa.harvard.edu [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741, Garching (Germany)

    2017-01-01

    The intracluster medium (ICM), as a magnetized and highly ionized fluid, provides an ideal laboratory to study plasma physics under extreme conditions that cannot be achieved on Earth. NGC 1404 is a bright elliptical galaxy that is being gas stripped as it falls through the ICM of the Fornax Cluster. We use the new Chandra X-ray observations of NGC 1404 to study ICM microphysics. The interstellar medium of NGC 1404 is characterized by a sharp leading edge, 8 kpc from the Galaxy center, and a short downstream gaseous tail. Contact discontinuities are resolved on unprecedented spatial scales (0.″5 = 45 pc) due to the combination of the proximity of NGC 1404, the superb spatial resolution of Chandra , and the very deep (670 ks) exposure. At the leading edge, we observe sub-kiloparsec-scale eddies generated by Kelvin–Helmholtz instability (KHI) and put an upper limit of 5% Spitzer on the isotropic viscosity of the hot cluster plasma. We also observe mixing between the hot cluster gas and the cooler galaxy gas in the downstream stripped tail, which provides further evidence of a low viscosity plasma. The assumed ordered magnetic fields in the ICM ought to be smaller than 5 μ G to allow KHI to develop. The lack of an evident magnetic draping layer just outside the contact edge is consistent with such an upper limit.

  9. The ATLAS3D project - I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria

    Cappellari, Michele; Emsellem, Eric; Krajnović, Davor; McDermid, Richard M.; Scott, Nicholas; Verdoes Kleijn, G. A.; Young, Lisa M.; Alatalo, Katherine; Bacon, R.; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, M.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Khochfar, Sadegh; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Serra, Paolo; Weijmans, Anne-Marie

    2011-05-01

    The ATLAS3D project is a multiwavelength survey combined with a theoretical modelling effort. The observations span from the radio to the millimetre and optical, and provide multicolour imaging, two-dimensional kinematics of the atomic (H I), molecular (CO) and ionized gas (Hβ, [O III] and [N I]), together with the kinematics and population of the stars (Hβ, Fe5015 and Mg b), for a carefully selected, volume-limited (1.16 × 105 Mpc3) sample of 260 early-type (elliptical E and lenticular S0) galaxies (ETGs). The models include semi-analytic, N-body binary mergers and cosmological simulations of galaxy formation. Here we present the science goals for the project and introduce the galaxy sample and the selection criteria. The sample consists of nearby (D 15°) morphologically selected ETGs extracted from a parent sample of 871 galaxies (8 per cent E, 22 per cent S0 and 70 per cent spirals) brighter than MK statistically representative of the nearby galaxy population. We present the size-luminosity relation for the spirals and ETGs and show that the ETGs in the ATLAS3D sample define a tight red sequence in a colour-magnitude diagram, with few objects in the transition from the blue cloud. We describe the strategy of the SAURON integral field observations and the extraction of the stellar kinematics with the pPXF method. We find typical 1σ errors of ΔV≈ 6 km s-1, Δσ≈ 7 km s-1, Δh3≈Δh4≈ 0.03 in the mean velocity, the velocity dispersion and Gauss-Hermite (GH) moments for galaxies with effective dispersion σe≳ 120 km s-1. For galaxies with lower σe (≈40 per cent of the sample) the GH moments are gradually penalized by pPXF towards zero to suppress the noise produced by the spectral undersampling and only V and σ can be measured. We give an overview of the characteristics of the other main data sets already available for our sample and of the ongoing modelling projects.

  10. SDSS-IV MaNGA: Galaxy Pair Fraction and Correlated Active Galactic Nuclei

    Fu, Hai; Steffen, Joshua L.; Gross, Arran C.; Dai, Y. Sophia; Isbell, Jacob W.; Lin, Lihwai; Wake, David; Xue, Rui; Bizyaev, Dmitry; Pan, Kaike

    2018-04-01

    We have identified 105 galaxy pairs at z ∼ 0.04 with the MaNGA integral-field spectroscopic data. The pairs have projected separations between 1 and 30 kpc, and are selected to have radial velocity offsets less than 600 km s‑1 and stellar mass ratio between 0.1 and 1. The pair fraction increases with both the physical size of the integral-field unit and the stellar mass, consistent with theoretical expectations. We provide the best-fit analytical function of the pair fraction and find that ∼3% of M* galaxies are in close pairs. For both isolated galaxies and paired galaxies, active galactic nuclei (AGNs) are selected using emission-line ratios and Hα equivalent widths measured inside apertures at a fixed physical size. We find AGNs in ∼24% of the paired galaxies and binary AGNs in ∼13% of the pairs. To account for the selection biases in both the pair sample and the MaNGA sample, we compare the AGN comoving volume densities with those expected from the mass- and redshift-dependent AGN fractions. We find a strong (∼5×) excess of binary AGNs over random pairing and a mild (∼20%) deficit of single AGNs. The binary AGN excess increases from ∼2× to ∼6× as the projected separation decreases from 10–30 to 1–10 kpc. Our results indicate that the pairing of galaxies preserves the AGN duty cycle in individual galaxies but increases the population of binary AGNs through correlated activities. We suggest tidally induced galactic-scale shocks and AGN cross-ionization as two plausible channels to produce low-luminosity narrow-line-selected binary AGNs.

  11. Dissolved Massive Metal-rich Globular Clusters Can Cause the Range of UV Upturn Strengths Found among Early-type Galaxies

    Goudfrooij, Paul

    2018-04-01

    I discuss a scenario in which the ultraviolet (UV) upturn of giant early-type galaxies (ETGs) is primarily due to helium-rich stellar populations that formed in massive metal-rich globular clusters (GCs), which subsequently dissolved in the strong tidal field in the central regions of the massive host galaxy. These massive GCs are assumed to show UV upturns similar to those observed recently in M87, the central giant elliptical galaxy in the Virgo cluster of galaxies. Data taken from the literature reveal a strong correlation between the strength of the UV upturn and the specific frequency of metal-rich GCs in ETGs. Adopting a Schechter function parameterization of GC mass functions, simulations of long-term dynamical evolution of GC systems show that the observed correlation between UV upturn strength and GC specific frequency can be explained by variations in the characteristic truncation mass {{ \\mathcal M }}{{c}} such that {{ \\mathcal M }}{{c}} increases with ETG luminosity in a way that is consistent with observed GC luminosity functions in ETGs. These findings suggest that the nature of the UV upturn in ETGs and the variation of its strength among ETGs are causally related to that of helium-rich populations in massive GCs, rather than intrinsic properties of field stars in massive galactic spheroids. With this in mind, I predict that future studies will find that [N/Fe] decreases with increasing galactocentric radius in massive ETGs, and that such gradients have the largest amplitudes in ETGs with the strongest UV upturns.

  12. Understanding the formation and evolution of early-type galaxies based on newly developed single-burst stellar population synthesis models in the infrared

    Roeck, Benjamin

    2015-12-01

    whole optical and infrared wavelength range between 3500 and 50000Å which are almost completely based on spectra of observed stars (apart from two gaps which were fitted with theoretical stellar spectra) . We analyze the behaviour of the near-infrared (J - K) and the Spitzer ([3.6]-[4.5]) colour calculated from our models. For ages older than 3 Gyr, both colours depend only slightly on age and metallicity. However, for younger ages, both colours become redder which is caused by the asymptotic giant branch stars contributing significantly to the light in the infrared at ages between 0.1 and 3 Gyr. Furthermore, we find a satisfactory agreement between the optical and near-infrared colours measured from our models and the colours observed from various samples of globular clusters and early-type x galaxies. However, our model predictions are only able to reproduce correctly the Spitzer ([3.6]-[4.5]) colours of older, more massive galaxies that resemble a single-burst population. Younger, less massive and more metal-poor galaxies show redder colours than our models. This mismatch can be explained by a more extended star formation history of these galaxies which includes a metal-poor or/and young population. The Spitzer ([3.6]-[4.5]) colours derived from our models also agree very well with those from most other models available in this wavelength range as long as they also correctly take into account a strong CO absorption band situated at 4.5 μm. The model predictions for colours in the near-infrared, such as (J - K), differ more between the different sets of models, depending on the underlying prescriptions for the asymptotic giant branch stellar evolutionary phase. Compared to other authors, we adopt only a moderate contribution of asymptotic giant branch stars to our models. Our stellar population models allow us also to determine mass-to-light ratios in different infrared bands. Consequently, we can confirm that the massto- light ratio determined in the Spitzer [3

  13. SDSS IV MaNGA - metallicity and nitrogen abundance gradients in local galaxies

    Belfiore, Francesco; Maiolino, Roberto; Tremonti, Christy; Sánchez, Sebastian F.; Bundy, Kevin; Bershady, Matthew; Westfall, Kyle; Lin, Lihwai; Drory, Niv; Boquien, Médéric; Thomas, Daniel; Brinkmann, Jonathan

    2017-07-01

    We study the gas phase metallicity (O/H) and nitrogen abundance gradients traced by star-forming regions in a representative sample of 550 nearby galaxies in the stellar mass range 109-1011.5 M⊙ with resolved spectroscopic data from the Sloan Digital Sky Survey IV Mapping Nearby Galaxies at Apache Point Observatory survey. Using strong-line ratio diagnostics (R23 and O3N2 for metallicity and N2O2 for N/O) and referencing to the effective (half-light) radius (Re), we find that the metallicity gradient steepens with stellar mass, lying roughly flat among galaxies with log (M⋆/M⊙) = 9.0 but exhibiting slopes as steep as -0.14 dex R_e^{-1} at log (M⋆/M⊙) = 10.5 (using R23, but equivalent results are obtained using O3N2). At higher masses, these slopes remain typical in the outer regions of our sample (R > 1.5Re), but a flattening is observed in the central regions (R 2.0Re), we detect a mild flattening of the metallicity gradient in stacked profiles, although with low significance. The N/O ratio gradient provides complementary constraints on the average chemical enrichment history. Unlike the oxygen abundance, the average N/O profiles do not flatten out in the central regions of massive galaxies. The metallicity and N/O profiles both depart significantly from an exponential form, suggesting a disconnect between chemical enrichment and stellar mass surface density on local scales. In the context of inside-out growth of discs, our findings suggest that central regions of massive galaxies today have evolved to an equilibrium metallicity, while the nitrogen abundance continues to increase as a consequence of delayed secondary nucleosynthetic production.

  14. THE SL2S GALAXY-SCALE LENS SAMPLE. IV. THE DEPENDENCE OF THE TOTAL MASS DENSITY PROFILE OF EARLY-TYPE GALAXIES ON REDSHIFT, STELLAR MASS, AND SIZE

    Sonnenfeld, Alessandro; Treu, Tommaso; Suyu, Sherry H. [Physics Department, University of California, Santa Barbara, CA 93106 (United States); Gavazzi, Raphaël [Institut d' Astrophysique de Paris, UMR7095 CNRS-Université Pierre et Marie Curie, 98bis bd Arago, F-75014 Paris (France); Marshall, Philip J. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305 (United States); Auger, Matthew W. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Nipoti, Carlo, E-mail: sonnen@physics.ucsb.edu [Astronomy Department, University of Bologna, via Ranzani 1, I-40127 Bologna (Italy)

    2013-11-10

    We present optical and near-infrared spectroscopy obtained at Keck, Very Large Telescope, and Gemini for a sample of 36 secure strong gravitational lens systems and 17 candidates identified as part of the Strong Lensing Legacy Survey. The deflectors are massive early-type galaxies in the redshift range z{sub d} = 0.2-0.8, while the lensed sources are at z{sub s} = 1-3.5. We combine these data with photometric and lensing measurements presented in the companion paper III and with lenses from the Sloan Lens Advanced Camera for Surveys and Lènses Structure and Dynamics surveys to investigate the cosmic evolution of the internal structure of massive early-type galaxies over half the age of the universe. We study the dependence of the slope of the total mass density profile, γ' (ρ(r)∝r{sup -γ{sup '}}), on stellar mass, size, and redshift. We find that two parameters are sufficient to determine γ' with less than 6% residual scatter. At fixed redshift, γ' depends solely on the surface stellar mass density ∂γ'/∂Σ{sub *} = 0.38 ± 0.07, i.e., galaxies with denser stars also have steeper slopes. At fixed M{sub *} and R{sub eff}, γ' depends on redshift, in the sense that galaxies at a lower redshift have steeper slopes (∂γ'/∂z = –0.31 ± 0.10). However, the mean redshift evolution of γ' for an individual galaxy is consistent with zero dγ'/dz = –0.10 ± 0.12. This result is obtained by combining our measured dependencies of γ' on z, M{sub *},R{sub eff} with the evolution of the R{sub eff}-M{sub *} taken from the literature, and is broadly consistent with current models of the formation and evolution of massive early-type galaxies. Detailed quantitative comparisons of our results with theory will provide qualitatively new information on the detailed physical processes at work.

  15. A PANCHROMATIC CATALOG OF EARLY-TYPE GALAXIES AT INTERMEDIATE REDSHIFT IN THE HUBBLE SPACE TELESCOPE WIDE FIELD CAMERA 3 EARLY RELEASE SCIENCE FIELD

    Rutkowski, M. J.; Cohen, S. H.; Windhorst, R. A.; Kaviraj, S.; Crockett, R. M.; Silk, J.; O'Connell, R. W.; Hathi, N. P.; McCarthy, P. J.; Ryan, R. E. Jr.; Koekemoer, A.; Bond, H. E.; Yan, H.; Kimble, R. A.; Balick, B.; Calzetti, D.; Disney, M. J.; Dopita, M. A.; Frogel, J. A.; Hall, D. N. B.

    2012-01-01

    In the first of a series of forthcoming publications, we present a panchromatic catalog of 102 visually selected early-type galaxies (ETGs) from observations in the Early Release Science (ERS) program with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) of the Great Observatories Origins Deep Survey-South (GOODS-S) field. Our ETGs span a large redshift range, 0.35 ∼ 11 * [M ☉ ] 12 . By transforming the observed photometry into the Galaxy Evolution Explorer FUV and NUV, Johnson V, and Sloan Digital Sky Survey g' and r' bandpasses we identify a noteworthy diversity in the rest-frame UV-optical colors and find the mean rest-frame (FUV–V) = 3.5 and (NUV–V) = 3.3, with 1σ standard deviations ≅1.0. The blue rest-frame UV-optical colors observed for most of the ETGs are evidence for star formation during the preceding gigayear, but no systems exhibit UV-optical photometry consistent with major recent (∼<50 Myr) starbursts. Future publications which address the diversity of stellar populations likely to be present in these ETGs, and the potential mechanisms by which recent star formation episodes are activated, are discussed.

  16. DISCOVERY OF DRAMATIC OPTICAL VARIABILITY IN SDSS J1100+4421: A PECULIAR RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXY?

    Tanaka, Masaomi [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Morokuma, Tomoki; Doi, Mamoru; Kikuchi, Yuki [Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo 181-0015 (Japan); Itoh, Ryosuke [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Akitaya, Hiroshi; Tanaka, Yasuyuki T.; Kawabata, Koji S. [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Tominaga, Nozomu [Department of Physics, Faculty of Science and Engineering, Konan University, Kobe, Hyogo 658-8501 (Japan); Saito, Yoshihiko; Kawai, Nobuyuki [Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Stawarz, Łukasz [Institute of Space and Astronautical Science, JAXA, Sagamihara, Kanagawa 252-5210 (Japan); Gandhi, Poshak [Department of Physics, Durham University, Durham DH1-3LE (United Kingdom); Ali, Gamal; Essam, Ahmad; Hamed, Gamal [National Research Institute of Astronomy and Geophysics, Helwan, Cairo (Egypt); Aoki, Tsutomu [Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, Kiso, Nagano 397-0101 (Japan); Contreras, Carlos; Hsiao, Eric Y. [Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Iwata, Ikuru, E-mail: masaomi.tanaka@nao.ac.jp [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); and others

    2014-10-01

    We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z = 0.840, however, with unusually strong narrow emission lines. The estimated black hole mass of ∼10{sup 7} M {sub ☉} implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R ≅ 4 × 10{sup 2}-3 × 10{sup 3}, which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and γ-ray-loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxies.

  17. Nature vs. nurture in the low-density environment: structure and evolution of early-type dwarf galaxies in poor groups

    Annibali, F.; Grützbauch, R.; Rampazzo, R.; Bressan, A.; Zeilinger, W. W.

    2011-04-01

    We present the stellar population properties of 13 dwarf galaxies residing in poor groups (low-density environment, LDE) observed with VIMOS at VLT. Ages, metallicities, and [α/Fe] ratios were derived within an r < re/2 aperture from the Lick indices Hβ, Mgb, Fe5270, and Fe5335 through comparison with our simple stellar population (SSP) models that account for variable [α/Fe] ratios. For a fiducial subsample of 10 early-type dwarfs, we derived median values and scatters around the medians of 5.7 ± 4.4 Gyr, -0.26 ± 0.28, and -0.04 ± 0.33 for age, log Z/Z⊙, and [α/Fe] , respectively. For a selection of bright early-type galaxies (ETGs) from an earlier sample residing in a comparable environment, we derive median values of 9.8 ± 4.1 Gyr, 0.06 ± 0.16, and 0.18 ± 0.13 for the same stellar population parameters. It follows that dwarfs are on average younger, less metal rich, and less enhanced in the α-elements than giants, in agreement with the extrapolation to the low-mass regime of the scaling relations derived for giant ETGs. From the total (dwarf + giant) sample, we find that age ∝ σ0.39 ± 0.22, Z ∝ σ0.80 ± 0.16, and α/Fe ∝ σ0.42 ± 0.22. We also find correlations with morphology, in the sense that the metallicity and the [α/Fe] ratio increase with the Sersic index n or with the bulge-to-total light fraction B/T. The presence of a strong morphology-[α/Fe] relation appears to contradict the possible evolution along the Hubble sequence from low B/T (low n) to high B/T (high n) galaxies. We also investigate the role played by environment by comparing the properties of our LDE dwarfs with those of Coma red passive dwarfs from the literature. We find possible evidence that LDE dwarfs experienced more prolonged star formations than Coma dwarfs, however larger data samples are needed to draw firmer conclusions. Based on observations obtained at the European Southern Observatory, La Silla, Chile.

  18. The ATLAS3D project - IX. The merger origin of a fast- and a slow-rotating early-type galaxy revealed with deep optical imaging: first results

    Duc, Pierre-Alain; Cuillandre, Jean-Charles; Serra, Paolo; Michel-Dansac, Leo; Ferriere, Etienne; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Cappellari, Michele; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Weijmans, Anne-Marie; Young, Lisa M.

    2011-10-01

    The mass assembly of galaxies leaves imprints in their outskirts, such as shells and tidal tails. The frequency and properties of such fine structures depend on the main acting mechanisms - secular evolution, minor or major mergers - and on the age of the last substantial accretion event. We use this to constrain the mass assembly history of two apparently relaxed nearby early-type galaxies (ETGs) selected from the ATLAS3D sample, NGC 680 and 5557. Our ultra-deep optical images obtained with MegaCam on the Canada-France-Hawaii Telescope reach 29 mag arcsec-2 in the g band. They reveal very low surface brightness (LSB) filamentary structures around these ellipticals. Among them, a gigantic 160 kpc long, narrow, tail east of NGC 5557 hosts three gas-rich star-forming objects, previously detected in H I with the Westerbork Synthesis Radio Telescope and in UV with GALEX. NGC 680 exhibits two major diffuse plumes apparently connected to extended H I tails, as well as a series of arcs and shells. Comparing the outer stellar and gaseous morphology of the two ellipticals with that predicted from models of colliding galaxies, we argue that the LSB features are tidal debris and that each of these two ETGs was assembled during a relatively recent, major wet merger, which most likely occurred after the redshift z ≃ 0.5 epoch. Had these mergers been older, the tidal features should have already fallen back or be destroyed by more recent accretion events. However, the absence of molecular gas and of a prominent young stellar population in the core region of the galaxies indicates that the merger is at least 1-2 Gyr old: the memory of any merger-triggered nuclear starburst has indeed been lost. The star-forming objects found towards the collisional debris of NGC 5557 are then likely tidal dwarf galaxies. Such recycled galaxies here appear to be long-lived and continue to form stars while any star formation activity has stopped in their parent galaxy. The inner kinematics of NGC

  19. MAPPING THE SIMILARITIES OF SPECTRA: GLOBAL AND LOCALLY-BIASED APPROACHES TO SDSS GALAXIES

    Lawlor, David [Statistical and Applied Mathematical Sciences Institute (United States); Budavári, Tamás [Dept. of Applied Mathematics and Statistics, The Johns Hopkins University (United States); Mahoney, Michael W. [International Computer Science Institute (United States)

    2016-12-10

    We present a novel approach to studying the diversity of galaxies. It is based on a novel spectral graph technique, that of locally-biased semi-supervised eigenvectors . Our method introduces new coordinates that summarize an entire spectrum, similar to but going well beyond the widely used Principal Component Analysis (PCA). Unlike PCA, however, this technique does not assume that the Euclidean distance between galaxy spectra is a good global measure of similarity. Instead, we relax that condition to only the most similar spectra, and we show that doing so yields more reliable results for many astronomical questions of interest. The global variant of our approach can identify very finely numerous astronomical phenomena of interest. The locally-biased variants of our basic approach enable us to explore subtle trends around a set of chosen objects. The power of the method is demonstrated in the Sloan Digital Sky Survey Main Galaxy Sample, by illustrating that the derived spectral coordinates carry an unprecedented amount of information.

  20. Mapping the Similarities of Spectra: Global and Locally-biased Approaches to SDSS Galaxies

    Lawlor, David; Budavári, Tamás; Mahoney, Michael W.

    2016-12-01

    We present a novel approach to studying the diversity of galaxies. It is based on a novel spectral graph technique, that of locally-biased semi-supervised eigenvectors. Our method introduces new coordinates that summarize an entire spectrum, similar to but going well beyond the widely used Principal Component Analysis (PCA). Unlike PCA, however, this technique does not assume that the Euclidean distance between galaxy spectra is a good global measure of similarity. Instead, we relax that condition to only the most similar spectra, and we show that doing so yields more reliable results for many astronomical questions of interest. The global variant of our approach can identify very finely numerous astronomical phenomena of interest. The locally-biased variants of our basic approach enable us to explore subtle trends around a set of chosen objects. The power of the method is demonstrated in the Sloan Digital Sky Survey Main Galaxy Sample, by illustrating that the derived spectral coordinates carry an unprecedented amount of information.

  1. MAPPING THE SIMILARITIES OF SPECTRA: GLOBAL AND LOCALLY-BIASED APPROACHES TO SDSS GALAXIES

    Lawlor, David; Budavári, Tamás; Mahoney, Michael W.

    2016-01-01

    We present a novel approach to studying the diversity of galaxies. It is based on a novel spectral graph technique, that of locally-biased semi-supervised eigenvectors . Our method introduces new coordinates that summarize an entire spectrum, similar to but going well beyond the widely used Principal Component Analysis (PCA). Unlike PCA, however, this technique does not assume that the Euclidean distance between galaxy spectra is a good global measure of similarity. Instead, we relax that condition to only the most similar spectra, and we show that doing so yields more reliable results for many astronomical questions of interest. The global variant of our approach can identify very finely numerous astronomical phenomena of interest. The locally-biased variants of our basic approach enable us to explore subtle trends around a set of chosen objects. The power of the method is demonstrated in the Sloan Digital Sky Survey Main Galaxy Sample, by illustrating that the derived spectral coordinates carry an unprecedented amount of information.

  2. Globular clusters and planetary nebulae kinematics and X-ray emission in the early-type galaxy NGC 5128

    Samurović S.

    2006-01-01

    Full Text Available The estimates of the mass of the galaxy NGC 5128 based on the different mass tracers, globular clusters (GCs and planetary nebulae (PNe, are presented. These estimates are compared with the estimate based on the X-ray methodology and it is found that the results for the mass (and mass-to-light ratio for all three approaches are in very good agreement interior to 25 arcmin; beyond 25 arcmin the X-rays predict the mass which is too high with respect to the one found using GCs and PNe. Some possible explanations for this discrepancy were discussed. The Jeans equation is also solved and its predictions for the velocity dispersion are then compared with the observed values, which extend to ~8 effective radii in the case of the GCs and ~15 effective radii in the case of the PNe. It is found that interior to ~25 arcmin (~5 effective radii dark matter does not dominate because the total mass-to-light ratio in the B band in solar units is less than 10. Based on the GCs and PNe beyond ~25 arcmin the total mass-to-light ratio increases to ~14 (at ~80 arcmin which indicates the existence of dark matter in the outer regions of NGC 5128.

  3. NEW NEUTRINO MASS BOUNDS FROM SDSS-III DATA RELEASE 8 PHOTOMETRIC LUMINOUS GALAXIES

    De Putter, Roland [ICC, University of Barcelona (IEEC-UB), Marti i Franques 1, E-08028 Barcelona (Spain); Mena, Olga; Giusarma, Elena [Instituto de Fisica Corpuscular, University of Valencia-CSIC (Spain); Ho, Shirley; Seo, Hee-Jong; White, Martin; Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Cuesta, Antonio [Yale University, New Haven, CT (United States); Ross, Ashley J.; Percival, Will J. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Bizyaev, Dmitry; Brewington, Howard; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Pan, Kaike; Shelden, Alaina; Simmons, Audrey [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Kirkby, David [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); and others

    2012-12-10

    We present neutrino mass bounds using 900,000 luminous galaxies with photometric redshifts measured from Sloan Digital Sky Survey III Data Release 8. The galaxies have photometric redshifts between z = 0.45 and z = 0.65 and cover 10,000 deg{sup 2}, thus probing a volume of 3 h {sup -3} Gpc{sup 3} and enabling tight constraints to be derived on the amount of dark matter in the form of massive neutrinos. A new bound on the sum of neutrino masses {Sigma}m{sub {nu}} < 0.27 eV, at the 95% confidence level (CL), is obtained after combining our sample of galaxies, which we call ''CMASS'', with Wilkinson Microwave Anisotropy Probe (WMAP) seven-year cosmic microwave background data and the most recent measurement of the Hubble parameter from the Hubble Space Telescope (HST). This constraint is obtained with a conservative multipole range of 30 < l < 200 in order to minimize nonlinearities, and a free bias parameter in each of the four redshift bins. We study the impact of assuming this linear galaxy bias model using mock catalogs and find that this model causes a small ({approx}1{sigma}-1.5{sigma}) bias in {Omega}{sub DM} h {sup 2}. For this reason, we also quote neutrino bounds based on a conservative galaxy bias model containing additional, shot-noise-like free parameters. In this conservative case, the bounds are significantly weakened, e.g., {Sigma}m{sub {nu}} < 0.38 eV (95% CL) for WMAP+HST+CMASS (l{sub max} = 200). We also study the dependence of the neutrino bound on the multipole range (l{sub max} = 150 versus l{sub max} = 200) and on which combination of data sets is included as a prior. The addition of supernova and/or baryon acoustic oscillation data does not significantly improve the neutrino mass bound once the HST prior is included. A companion paper describes the construction of the angular power spectra in detail and derives constraints on a general cosmological model, including the dark energy equation of state w and the spatial

  4. THE MASS-METALLICITY RELATION WITH THE DIRECT METHOD ON STACKED SPECTRA OF SDSS GALAXIES

    Andrews, Brett H.; Martini, Paul, E-mail: andrews@astronomy.ohio-state.edu [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

    2013-03-10

    The relation between galaxy stellar mass and gas-phase metallicity is a sensitive diagnostic of the main processes that drive galaxy evolution, namely cosmological gas inflow, metal production in stars, and gas outflow via galactic winds. We employed the direct method to measure the metallicities of {approx}200,000 star-forming galaxies from the Sloan Digital Sky Survey that were stacked in bins of (1) stellar mass and (2) both stellar mass and star formation rate (SFR) to significantly enhance the signal-to-noise ratio of the weak [O III] {lambda}4363 and [O II] {lambda}{lambda}7320, 7330 auroral lines required to apply the direct method. These metallicity measurements span three decades in stellar mass from log(M{sub *}/M{sub Sun }) = 7.4-10.5, which allows the direct method mass-metallicity relation to simultaneously capture the high-mass turnover and extend a full decade lower in mass than previous studies that employed more uncertain strong line methods. The direct method mass-metallicity relation rises steeply at low mass (O/H {proportional_to} M{sub *} {sup 1/2}) until it turns over at log(M{sub *}/M{sub Sun }) = 8.9 and asymptotes to 12 + log(O/H) = 8.8 at high mass. The direct method mass-metallicity relation has a steeper slope, a lower turnover mass, and a factor of two to three greater dependence on SFR than strong line mass-metallicity relations. Furthermore, the SFR-dependence appears monotonic with stellar mass, unlike strong line mass-metallicity relations. We also measure the N/O abundance ratio, an important tracer of star formation history, and find the clear signature of primary and secondary nitrogen enrichment. N/O correlates tightly with oxygen abundance, and even more so with stellar mass.

  5. SDSS IV MaNGA—Rotation Velocity Lags in the Extraplanar Ionized Gas from MaNGA Observations of Edge-on Galaxies

    Bizyaev, D.; Pan, K.; Brinkmann, J. [Apache Point Observatory and New Mexico State University, Sunspot, NM 88349 (United States); Walterbos, R. A. M. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Yoachim, P. [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Riffel, R. A. [Departamento de Física, CCNE, Universidade Federal de Santa Maria, Av. Roraima, 1000-97105-900, Santa Maria, RS (Brazil); Fernández-Trincado, J. G. [Institut Utinam, CNRS UMR 6213, Université de Franche-Comté, OSU THETA Franche-Comté-Bourgogne, Observatoire de Besançon, BP 1615, F-25010 Besançon Cedex (France); Diamond-Stanic, A. M. [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States); Jones, A. [Max-Planck Institute for Astrophysics, Karl-Schwarzschild-Str 1, Garching, D-85748 (Germany); Thomas, D. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth PO1 3FX (United Kingdom); Cleary, J. [Department of Physics and Astronomy, Johns Hopkins University, Bloomberg Center, 3400 North Charles Street, Baltimore, MD 21218 (United States)

    2017-04-20

    We present a study of the kinematics of the extraplanar ionized gas around several dozen galaxies observed by the Mapping of Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. We considered a sample of 67 edge-on galaxies out of more than 1400 extragalactic targets observed by MaNGA, in which we found 25 galaxies (or 37%) with regular lagging of the rotation curve at large distances from the galactic midplane. We model the observed H α emission velocity fields in the galaxies, taking projection effects and a simple model for the dust extinction into account. We show that the vertical lag of the rotation curve is necessary in the modeling, and estimate the lag amplitude in the galaxies. We find no correlation between the lag and the star formation rate in the galaxies. At the same time, we report a correlation between the lag and the galactic stellar mass, central stellar velocity dispersion, and axial ratio of the light distribution. These correlations suggest a possible higher ratio of infalling-to-local gas in early-type disk galaxies or a connection between lags and the possible presence of hot gaseous halos, which may be more prevalent in more massive galaxies. These results again demonstrate that observations of extraplanar gas can serve as a potential probe for accretion of gas.

  6. SDSS IV MaNGA—Rotation Velocity Lags in the Extraplanar Ionized Gas from MaNGA Observations of Edge-on Galaxies

    Bizyaev, D.; Pan, K.; Brinkmann, J.; Walterbos, R. A. M.; Yoachim, P.; Riffel, R. A.; Fernández-Trincado, J. G.; Diamond-Stanic, A. M.; Jones, A.; Thomas, D.; Cleary, J.

    2017-01-01

    We present a study of the kinematics of the extraplanar ionized gas around several dozen galaxies observed by the Mapping of Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. We considered a sample of 67 edge-on galaxies out of more than 1400 extragalactic targets observed by MaNGA, in which we found 25 galaxies (or 37%) with regular lagging of the rotation curve at large distances from the galactic midplane. We model the observed H α emission velocity fields in the galaxies, taking projection effects and a simple model for the dust extinction into account. We show that the vertical lag of the rotation curve is necessary in the modeling, and estimate the lag amplitude in the galaxies. We find no correlation between the lag and the star formation rate in the galaxies. At the same time, we report a correlation between the lag and the galactic stellar mass, central stellar velocity dispersion, and axial ratio of the light distribution. These correlations suggest a possible higher ratio of infalling-to-local gas in early-type disk galaxies or a connection between lags and the possible presence of hot gaseous halos, which may be more prevalent in more massive galaxies. These results again demonstrate that observations of extraplanar gas can serve as a potential probe for accretion of gas.

  7. SDSS IV MaNGA—Rotation Velocity Lags in the Extraplanar Ionized Gas from MaNGA Observations of Edge-on Galaxies

    Bizyaev, D.; Walterbos, R. A. M.; Yoachim, P.; Riffel, R. A.; Fernández-Trincado, J. G.; Pan, K.; Diamond-Stanic, A. M.; Jones, A.; Thomas, D.; Cleary, J.; Brinkmann, J.

    2017-04-01

    We present a study of the kinematics of the extraplanar ionized gas around several dozen galaxies observed by the Mapping of Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. We considered a sample of 67 edge-on galaxies out of more than 1400 extragalactic targets observed by MaNGA, in which we found 25 galaxies (or 37%) with regular lagging of the rotation curve at large distances from the galactic midplane. We model the observed Hα emission velocity fields in the galaxies, taking projection effects and a simple model for the dust extinction into account. We show that the vertical lag of the rotation curve is necessary in the modeling, and estimate the lag amplitude in the galaxies. We find no correlation between the lag and the star formation rate in the galaxies. At the same time, we report a correlation between the lag and the galactic stellar mass, central stellar velocity dispersion, and axial ratio of the light distribution. These correlations suggest a possible higher ratio of infalling-to-local gas in early-type disk galaxies or a connection between lags and the possible presence of hot gaseous halos, which may be more prevalent in more massive galaxies. These results again demonstrate that observations of extraplanar gas can serve as a potential probe for accretion of gas.

  8. CROSS-CORRELATION WEAK LENSING OF SDSS GALAXY CLUSTERS. I. MEASUREMENTS

    Sheldon, Erin S.; Johnston, David E.; Scranton, Ryan; Koester, Benjamin P.; Oyaizu, Hiroaki; Cunha, Carlos; Lima, Marcos; Frieman, Joshua A.; McKay, Timothy A.; Lin Huan; Annis, James; Wechsler, Risa H.; Mandelbaum, Rachel; Bahcall, Neta A.; Fukugita, Masataka

    2009-01-01

    This is the first in a series of papers on the weak lensing effect caused by clusters of galaxies in Sloan Digital Sky Survey. The photometrically selected cluster sample, known as MaxBCG, includes ∼130,000 objects between redshift 0.1 and 0.3, ranging in size from small groups to massive clusters. We split the clusters into bins of richness and luminosity and stack the surface density contrast to produce mean radial profiles. The mean profiles are detected over a range of scales, from the inner halo (25 kpc h -1 ) well into the surrounding large-scale structure (30 Mpc h -1 ), with a significance of 15 to 20 in each bin. The signal over this large range of scales is best interpreted in terms of the cluster-mass cross-correlation function. We pay careful attention to sources of systematic error, correcting for them where possible. The resulting signals are calibrated to the ∼10% level, with the dominant remaining uncertainty being the redshift distribution of the background sources. We find that the profiles scale strongly with richness and luminosity. We find that the signal within a given richness bin depends upon luminosity, suggesting that luminosity is more closely correlated with mass than galaxy counts. We split the samples by redshift but detect no significant evolution. The profiles are not well described by power laws. In a subsequent series of papers, we invert the profiles to three-dimensional mass profiles, show that they are well fit by a halo model description, measure mass-to-light ratios, and provide a cosmological interpretation.

  9. Inferring the star-formation histories of the most massive and passive early-type galaxies at z < 0.3

    Citro, Annalisa; Pozzetti, Lucia; Moresco, Michele; Cimatti, Andrea

    2016-07-01

    Context. In the Λ cold dark matter (ΛCDM) cosmological framework, massive galaxies are the end-points of the hierarchical evolution and are therefore key probes for understanding how the baryonic matter evolves within the dark matter halos. Aims: The aim of this work is to use the archaeological approach in order to infer the stellar population properties and star formation histories of the most massive (M > 1010.75 M⊙) and passive early-type galaxies (ETGs) at 0 tests have been performed to assess the reliability of STARLIGHT to retrieve the evolutionary properties of the ETG stellar populations such as the age, metallicity and star formation history. The results indicate that these properties can be derived with accuracy better than 10% at S/N ≳ 10-20, and also that the procedure of stacking galaxy spectra does not introduce significant biases into their retrieval. Results: Based on our spectral analysis, we found that the ETGs of our sample are very old systems - the most massive ones are almost as old as the Universe. The stellar metallicities are slightly supersolar, with a mean of Z ~ 0.027 ± 0.002 and Z ~ 0.029 ± 0.0015 (depending on the spectral synthesis models used for the fit) and do not depend on redshift. Dust extinction is very low, with a mean of AV ~ 0.08 ± 0.030 mag and AV ~ 0.16 ± 0.048 mag. The ETGs show an anti-hierarchical evolution (downsizing) where more massive galaxies are older. The SFHs can be approximated with a parametric function of the form SFR(t) ∝ τ- (c + 1)tc exp(-t/τ), with typical short e-folding times of τ ~ 0.6-0.8 Gyr (with a dispersion of ±0.1 Gyr) and c ~ 0.1 (with a dispersion of ±0.05). Based on the reconstructed SFHs, most of the stellar mass (≳75%) was assembled by z ~ 5 and ≲4% of it can be ascribed to stellar populations younger than ~1 Gyr. The inferred SFHs are also used to place constraints on the properties and evolution of the ETG progenitors. In particular, the ETGs of our samples should have

  10. CROSS-CORRELATION WEAK LENSING OF SDSS GALAXY CLUSTERS. III. MASS-TO-LIGHT RATIOS

    Sheldon, Erin S.; Johnston, David E.; Masjedi, Morad; Blanton, Michael R.; McKay, Timothy A.; Scranton, Ryan; Wechsler, Risa H.; Koester, Benjamin P.; Hansen, Sarah M.; Frieman, Joshua A.; Annis, James

    2009-01-01

    We present measurements of the excess mass-to-light ratio (M/L) measured around MaxBCG galaxy clusters observed in the Sloan Digital Sky Survey. This red-sequence cluster sample includes objects from small groups with M 200 ∼ 5 x 10 12 h -1 M sun to clusters with M 200 ∼ 10 15 h -1 M sun . Using cross-correlation weak lensing, we measure the excess mass density profile above the universal mean Δρ(r)=ρ(r)-ρ-bar for clusters in bins of richness and optical luminosity. We also measure the excess luminosity density Δl(r)=l(r)-l-bar measured in the z = 0.25 i band. For both mass and light, we de-project the profiles to produce three-dimensional mass and light profiles over scales from 25 h -1 kpc to 22 h -1 Mpc. From these profiles we calculate the cumulative excess mass ΔM(r) and excess light ΔL(r) as a function of separation from the BCG. On small scales, where ρ(r)>>ρ-bar, the integrated mass-to-light profile (ΔM/ΔL)(r) may be interpreted as the cluster M/L. We find the (ΔM/ΔL) 200 , the M/L within r 200 , scales with cluster mass as a power law with index 0.33 ± 0.02. On large scales, where ρ(r)∼ρ-bar, the ΔM/ΔL approaches an asymptotic value independent of cluster richness. For small groups, the mean (ΔM/ΔL) 200 is much smaller than the asymptotic value, while for large clusters (ΔM/ΔL) 200 is consistent with the asymptotic value. This asymptotic value should be proportional to the mean M/L of the universe (M/L). We find (M/L)b -2 M/L = 362 ± 54h (statistical). There is additional uncertainty in the overall calibration at the ∼10% level. The parameter b 2 M/L is primarily a function of the bias of the L ∼ * galaxies used as light tracers, and should be of order unity. Multiplying by the luminosity density in the same bandpass we find Ω m b -2 M/L = 0.20 ± 0.03, independent of the Hubble parameter.

  11. A PANCHROMATIC CATALOG OF EARLY-TYPE GALAXIES AT INTERMEDIATE REDSHIFT IN THE HUBBLE SPACE TELESCOPE WIDE FIELD CAMERA 3 EARLY RELEASE SCIENCE FIELD

    Rutkowski, M. J.; Cohen, S. H.; Windhorst, R. A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Kaviraj, S.; Crockett, R. M.; Silk, J. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); O' Connell, R. W. [Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903 (United States); Hathi, N. P.; McCarthy, P. J. [Observatories of the Carnegie Institute of Washington, Pasadena, CA 91101 (United States); Ryan, R. E. Jr.; Koekemoer, A.; Bond, H. E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Yan, H. [Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Kimble, R. A. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Disney, M. J. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Dopita, M. A. [Research School of Physics and Astronomy, The Australian National University, ACT 2611 (Australia); Frogel, J. A. [Astronomy Department, King Abdulaziz University, P.O. Box 80203, Jeddah (Saudi Arabia); Hall, D. N. B. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); and others

    2012-03-01

    In the first of a series of forthcoming publications, we present a panchromatic catalog of 102 visually selected early-type galaxies (ETGs) from observations in the Early Release Science (ERS) program with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) of the Great Observatories Origins Deep Survey-South (GOODS-S) field. Our ETGs span a large redshift range, 0.35 {approx}< z {approx}< 1.5, with each redshift spectroscopically confirmed by previous published surveys of the ERS field. We combine our measured WFC3 ERS and Advanced Camera for Surveys (ACS) GOODS-S photometry to gain continuous sensitivity from the rest-frame far-UV to near-IR emission for each ETG. The superior spatial resolution of the HST over this panchromatic baseline allows us to classify the ETGs by their small-scale internal structures, as well as their local environment. By fitting stellar population spectral templates to the broadband photometry of the ETGs, we determine that the average masses of the ETGs are comparable to the characteristic stellar mass of massive galaxies, 10{sup 11} < M{sub *}[M{sub Sun }]<10{sup 12}. By transforming the observed photometry into the Galaxy Evolution Explorer FUV and NUV, Johnson V, and Sloan Digital Sky Survey g' and r' bandpasses we identify a noteworthy diversity in the rest-frame UV-optical colors and find the mean rest-frame (FUV-V) = 3.5 and (NUV-V) = 3.3, with 1{sigma} standard deviations {approx_equal}1.0. The blue rest-frame UV-optical colors observed for most of the ETGs are evidence for star formation during the preceding gigayear, but no systems exhibit UV-optical photometry consistent with major recent ({approx}<50 Myr) starbursts. Future publications which address the diversity of stellar populations likely to be present in these ETGs, and the potential mechanisms by which recent star formation episodes are activated, are discussed.

  12. A Detection of the Baryon Acoustic Oscillation Features in the SDSS BOSS DR12 Galaxy Bispectrum

    Pearson, David W.; Samushia, Lado

    2018-05-01

    We present the first high significance detection (4.1σ) of the Baryon Acoustic Oscillations (BAO) feature in the galaxy bispectrum of the twelfth data release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS sample (0.43 ≤ z ≤ 0.7). We measured the scale dilation parameter, α, using the power spectrum, bispectrum, and both simultaneously for DR12, plus 2048 MultiDark-PATCHY mocks in the North and South Galactic Caps (NGC and SGC, respectively), and the volume weighted averages of those two samples (N+SGC). The fitting to the mocks validated our analysis pipeline, yielding values consistent with the mock cosmology. By fitting to the power spectrum and bispectrum separately, we tested the robustness of our results, finding consistent values from the NGC, SGC and N+SGC in all cases. We found DV = 2032 ± 24(stat.) ± 15(sys.) Mpc, DV = 2038 ± 55(stat.) ± 15(sys.) Mpc, and DV = 2031 ± 22(stat.) ± 10(sys.) Mpc from the N+SGC power spectrum, bispectrum and simultaneous fitting, respectively. Our bispectrum measurement precision was mainly limited by the size of the covariance matrix. Based on the fits to the mocks, we showed that if a less noisy estimator of the covariance were available, from either a theoretical computation or a larger suite of mocks, the constraints from the bispectrum and simultaneous fits would improve to 1.1 per cent (1.3 per cent with systematics) and 0.7 per cent (0.9 per cent with systematics), respectively, with the latter being slightly more precise than the power spectrum only constraints from the reconstructed field.

  13. Cosmological parameter analysis including SDSS Lyα forest and galaxy bias: Constraints on the primordial spectrum of fluctuations, neutrino mass, and dark energy

    Seljak, Uros; Makarov, Alexey; McDonald, Patrick; Anderson, Scott F.; Bahcall, Neta A.; Cen, Renyue; Gunn, James E.; Lupton, Robert H.; Schlegel, David J.; Brinkmann, J.; Burles, Scott; Doi, Mamoru; Ivezic, Zeljko; Kent, Stephen; Loveday, Jon; Munn, Jeffrey A.; Nichol, Robert C.; Ostriker, Jeremiah P.; Schneider, Donald P.; Berk, Daniel E. Vanden

    2005-01-01

    We combine the constraints from the recent Lyα forest analysis of the Sloan Digital Sky Survey (SDSS) and the SDSS galaxy bias analysis with previous constraints from SDSS galaxy clustering, the latest supernovae, and 1st year WMAP cosmic microwave background anisotropies. We find significant improvements on all of the cosmological parameters compared to previous constraints, which highlights the importance of combining Lyα forest constraints with other probes. Combining WMAP and the Lyα forest we find for the primordial slope n s =0.98±0.02. We see no evidence of running, dn/dlnk=-0.003±0.010, a factor of 3 improvement over previous constraints. We also find no evidence of tensors, r 2 model is within the 2-sigma contour, V∝φ 4 is outside the 3-sigma contour. For the amplitude we find σ 8 =0.90±0.03 from the Lyα forest and WMAP alone. We find no evidence of neutrino mass: for the case of 3 massive neutrino families with an inflationary prior, eV and the mass of lightest neutrino is m 1 ν λ =0.72±0.02, w(z=0.3)=-0.98 -0.12 +0.10 , the latter changing to w(z=0.3)=-0.92 -0.10 +0.09 if tensors are allowed. We find no evidence for variation of the equation of state with redshift, w(z=1)=-1.03 -0.28 +0.21 . These results rely on the current understanding of the Lyα forest and other probes, which need to be explored further both observationally and theoretically, but extensive tests reveal no evidence of inconsistency among different data sets used here

  14. FORMATION EPOCHS, STAR FORMATION HISTORIES, AND SIZES OF MASSIVE EARLY-TYPE GALAXIES IN CLUSTER AND FIELD ENVIRONMENTS AT z = 1.2: INSIGHTS FROM THE REST-FRAME ULTRAVIOLET

    Rettura, Alessandro; Demarco, R.; Ford, H. C.; Rosati, P.; Gobat, R.; Nonino, M.; Fosbury, R. A. E.; Menci, N.; Strazzullo, V.; Mei, S.

    2010-01-01

    We derive stellar masses, ages, and star formation histories (SFHs) of massive early-type galaxies in the z = 1.237 RDCS1252.9-2927 cluster and compare them with those measured in a similarly mass-selected sample of field contemporaries drawn from the Great Observatories Origin Deep Survey South Field. Robust estimates of these parameters are obtained by comparing a large grid of composite stellar population models with 8-9 band photometry in the rest-frame near-ultraviolet, optical, and IR, thus sampling the entire relevant domain of emission of the different stellar populations. Additionally, we present new, deep U-band photometry of both fields, giving access to the critical far-ultraviolet rest frame, in order to empirically constrain the dependence of the most recent star formation processes on the environment. We also analyze the morphological properties of both samples to examine the dependence of their scaling relations on their mass and environment. We find that early-type galaxies, both in the cluster and in the field, show analogous optical morphologies, follow comparable mass versus size relation, have congruent average surface stellar mass densities, and lie on the same Kormendy relation. We also show that a fraction of early-type galaxies in the field employ longer timescales, τ, to assemble their mass than their cluster contemporaries. Hence, we conclude that while the formation epoch of early-type galaxies only depends on their mass, the environment does regulate the timescales of their SFHs. Our deep U-band imaging strongly supports this conclusion. We show that cluster galaxies are at least 0.5 mag fainter than their field contemporaries of similar mass and optical-to-infrared colors, implying that the last episode of star formation must have happened more recently in the field than in the cluster.

  15. SDSS IV MaNGA: Deep observations of extra-planar, diffuse ionized gas around late-type galaxies from stacked IFU spectra

    Jones, A.; Kauffmann, G.; D'Souza, R.; Bizyaev, D.; Law, D.; Haffner, L.; Bahé, Y.; Andrews, B.; Bershady, M.; Brownstein, J.; Bundy, K.; Cherinka, B.; Diamond-Stanic, A.; Drory, N.; Riffel, R. A.; Sánchez, S. F.; Thomas, D.; Wake, D.; Yan, R.; Zhang, K.

    2017-03-01

    We have conducted a study of extra-planar diffuse ionized gas using the first year data from the MaNGA IFU survey. We have stacked spectra from 49 edge-on, late-type galaxies as a function of distance from the midplane of the galaxy. With this technique we can detect the bright emission lines Hα, Hβ, [O II]λλ3726, 3729, [O III]λ5007, [N II]λλ6549, 6584, and [S II]λλ6717, 6731 out to about 4 kpc above the midplane. With 16 galaxies we can extend this analysis out to about 9 kpc, I.e. a distance of 2Re, vertically from the midplane. In the halo, the surface brightnesses of the [O II] and Hα emission lines are comparable, unlike in the disk where Hα dominates. When we split the sample by specific star-formation rate, concentration index, and stellar mass, each subsample's emission line surface brightness profiles and ratios differ, indicating that extra-planar gas properties can vary. The emission line surface brightnesses of the gas around high specific star-formation rate galaxies are higher at all distances, and the line ratios are closer to ratios characteristic of H II regions compared with low specific star-formation rate galaxies. The less concentrated and lower stellar mass samples exhibit line ratios that are more like H II regions at larger distances than their more concentrated and higher stellar mass counterparts. The largest difference between different subsamples occurs when the galaxies are split by stellar mass. We additionally infer that gas far from the midplane in more massive galaxies has the highest temperatures and steepest radial temperature gradients based on their [N II]/Hα and [O II]/Hα ratios between the disk and the halo. SDSS IV.

  16. THE ACS FORNAX CLUSTER SURVEY. IV. DEPROJECTION OF THE SURFACE BRIGHTNESS PROFILES OF EARLY-TYPE GALAXIES IN THE VIRGO AND FORNAX CLUSTERS: INVESTIGATING THE 'CORE/POWER-LAW DICHOTOMY'

    Glass, Lisa; Ferrarese, Laura; Cote, Patrick; Blakeslee, John P.; Chen, Chin-Wei; Jordan, Andres; Infante, Leopoldo; Peng, Eric; Mei, Simona; Tonry, John L.; West, Michael J.

    2011-01-01

    Although early observations with the Hubble Space Telescope (HST) pointed to a sharp dichotomy among early-type galaxies in terms of the logarithmic slope γ' of their central surface brightness profiles, several studies in the past few years have called this finding into question. In particular, recent imaging surveys of 143 early-type galaxies belonging to the Virgo and Fornax Clusters using the Advanced Camera for Surveys (ACS) on board HST have not found a dichotomy in γ', but instead a systematic progression from central luminosity deficit to excess relative to the inward extrapolation of the best-fitting global Sersic model. Given that earlier studies also found that the dichotomy persisted when analyzing the deprojected density profile slopes, we investigate the distribution of the three-dimensional luminosity density profiles of the ACS Virgo and Fornax Cluster Survey galaxies. Having fitted the surface brightness profiles with modified Sersic models, we then deproject the galaxies using an Abel integral and measure the inner slopes γ 3D of the resulting luminosity density profiles at various fractions of the effective radius R e . We find no evidence of a dichotomy, but rather, a continuous variation in the central luminosity profiles as a function of galaxy magnitude. We introduce a parameter, Δ 3D , that measures the central deviation of the deprojected luminosity profiles from the global Sersic fit, showing that this parameter varies smoothly and systematically along the luminosity function.

  17. Type Ia Supernova Properties as a Function of the Distance to the Host Galaxy in the SDSS-II SN Survey

    Galbany, Lluis [Institut de Fisica d' Altes Energies (IFAE), Barcelona (Spain); et al.

    2012-08-20

    We use type-Ia supernovae (SNe Ia) discovered by the SDSS-II SN Survey to search for dependencies between SN Ia properties and the projected distance to the host galaxy center, using the distance as a proxy for local galaxy properties (local star-formation rate, local metallicity, etc.). The sample consists of almost 200 spectroscopically or photometrically confirmed SNe Ia at redshifts below 0.25. The sample is split into two groups depending on the morphology of the host galaxy. We fit light-curves using both MLCS2k2 and SALT2, and determine color (AV, c) and light-curve shape (delta, x1) parameters for each SN Ia, as well as its residual in the Hubble diagram. We then correlate these parameters with both the physical and the normalized distances to the center of the host galaxy and look for trends in the mean values and scatters of these parameters with increasing distance. The most significant (at the 4-sigma level) finding is that the average fitted AV from MLCS2k2 and c from SALT2 decrease with the projected distance for SNe Ia in spiral galaxies. We also find indications that SNe in elliptical galaxies tend to have narrower light-curves if they explode at larger distances, although this may be due to selection effects in our sample. We do not find strong correlations between the residuals of the distance moduli with respect to the Hubble flow and the galactocentric distances, which indicates a limited correlation between SN magnitudes after standardization and local host metallicity.

  18. Star Formation at z = 2.481 in the Lensed Galaxy SDSS J1110 = 6459. I. Lens Modeling and Source Reconstruction

    Johnson, Traci L.; Sharon, Keren; Gladders, Michael D.; Rigby, Jane R.; Bayliss, Matthew B.; Wuyts, Eva; Whitaker, Katherine E.; Florian, Michael; Murray, Katherine T.

    2017-07-01

    Using the combined resolving power of the Hubble Space Telescope and gravitational lensing, we resolve star-forming structures in a z˜ 2.5 galaxy on scales much smaller than the usual kiloparsec diffraction limit of HST. SGAS J111020.0+645950.8 is a clumpy, star-forming galaxy lensed by the galaxy cluster SDSS J1110+6459 at z=0.659, with a total magnification ˜ 30× across the entire arc. We use a hybrid parametric/non-parametric strong lensing mass model to compute the deflection and magnification of this giant arc, reconstruct the light distribution of the lensed galaxy in the source plane, and resolve the star formation into two dozen clumps. We develop a forward-modeling technique to model each clump in the source plane. We ray-trace the model to the image plane, convolve with the instrumental point-spread function (PSF), and compare with the GALFIT model of the clumps in the image plane, which decomposes clump structure from more extended emission. This technique has the advantage, over ray-tracing, of accounting for the asymmetric lensing shear of the galaxy in the image plane and the instrument PSF. At this resolution, we can begin to study star formation on a clump-by-clump basis, toward the goal of understanding feedback mechanisms and the buildup of exponential disks at high redshift. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program # 13003.

  19. X-RAY PROPERTIES OF YOUNG EARLY-TYPE GALAXIES. I. X-RAY LUMINOSITY FUNCTION OF LOW-MASS X-RAY BINARIES

    Kim, Dong-Woo; Fabbiano, Giuseppina

    2010-01-01

    We have compared the combined X-ray luminosity function (XLF) of low-mass X-ray binaries (LMXBs) detected in Chandra observations of young, post-merger elliptical galaxies with that of typical old elliptical galaxies. We find that the XLF of the 'young' sample does not present the prominent high-luminosity break at L X > 5 x 10 38 erg s -1 found in the old elliptical galaxy XLF. The 'young' and 'old' XLFs differ with a 3σ statistical significance (with a probability less than 0.2% that they derive from the same underlying parent distribution). Young elliptical galaxies host a larger fraction of luminous LMXBs (L X > 5 x 10 38 erg s -1 ) than old elliptical galaxies and the XLF of the young galaxy sample is intermediate between that of typical old elliptical galaxies and that of star-forming galaxies. This observational evidence may be related to the last major/minor mergers and the associated star formation.

  20. Hidden Imprints of Minor Merging in Early-Type Galaxies: Inner Polar Rings and Inclined Large-Scale Gaseous Disks In S0s

    Olga Sil’chenko

    2015-12-01

    Full Text Available I discuss my latest observational data and ideas about decoupled gaseous subsystems in nearby lenticular galaxies. As an extreme case of inclined gaseous disks, I demonstrate a sample of inner polar disks, derive their incidence, about 10% among the volume-limited nearby S0 galaxies, and discuss their origin. However, large-scale decoupled gaseous disks at intermediate inclinations are also a rather common phenomenon among the field S0 galaxies. I suggest that the geometry of outer gas accretion and the final morphology of the galaxy may be tightly related: inclined gas infall may prevent star formation in the accreted disk and force the disk galaxy to be a lenticular.

  1. Exploring the Nature of Galaxies with Abundance Gradient Anomalies in the SDSS-IV/MaNGA Survey

    Keith, Celeste; Tremonti, Christy; Pace, Zach; Schaefer, Adam

    2018-01-01

    Disk galaxies are known to have radial oxygen abundance gradients with their centers being more chemically enriched than their outskirts. The steepness of the abundance gradient has recently been shown to correlate with galaxy stellar mass, on average. However, individual galaxies sometimes show pronounced deviations from the expected trends, such as flatter or steeper slopes than expected for their mass, abrupt changes in slope, or azimuthal asymmetries. Here we report on a systematic search for galaxies with abundance gradient anomalies using 2-D spectroscopy from the Sloan Digital Sky Survey IV MaNGA. We construct nebular oxygen and nitrogen abundance maps for 300 moderately inclined non-interacting disk galaxies and use visual inspection to identify the most interesting cases. We use this training set to develop an automated pipeline to flag galaxies with abundance anomalies from the larger MaNGA dataset for visual inspection. We combine the metallicity maps with kinematic data and measurements of the galaxies' local environments to better understand the processes that shape the radial abundance gradients of disk galaxies.

  2. Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

    Barrera-Ballesteros, J. K.; Heckman, T. [Department of Physics and Astronomy, Johns Hopkins University, Bloomberg Center, 3400 N. Charles St., Baltimore, MD 21218 (United States); Sánchez, S. F. [Instituto de Astronomía, Universidad Nacional Autónoma de México, A.P. 70-264, 04510 México, D.F., México (Mexico); Blanc, G. A., E-mail: jbarrer3@jhu.edu [Observatories of the Carnegie Institution for Science, 813 Santa Barbara St, Pasadena, CA 91101 (United States); Collaboration: MaNGA Team

    2017-07-20

    We present the integrated stellar mass–metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R {sub eff}) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

  3. Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

    Barrera-Ballesteros, J. K.; Heckman, T.; Sánchez, S. F.; Blanc, G. A.

    2017-01-01

    We present the integrated stellar mass–metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R eff ) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

  4. Separate Ways: The Mass-Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

    Barrera-Ballesteros, J. K.; Sánchez, S. F.; Heckman, T.; Blanc, G. A.; The MaNGA Team

    2017-07-01

    We present the integrated stellar mass-metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R eff) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

  5. Changing ionization conditions in SDSS galaxies with active galactic nuclei as a function of environment from pairs to clusters

    Khabiboulline, Emil T.; Steinhardt, Charles L.; Silverman, John D.; Ellison, Sara L.; Mendel, J. Trevor; Patton, David R.

    2014-01-01

    We study how active galactic nucleus (AGN) activity changes across environments from galaxy pairs to clusters using 143,843 galaxies with z < 0.2 from the Sloan Digital Sky Survey. Using a refined technique, we apply a continuous measure of AGN activity, characteristic of the ionization state of the narrow-line emitting gas. Changes in key emission-line ratios ([N II] λ6548/Hα, [O III] λ5007/Hβ) between different samples allow us to disentangle different environmental effects while removing contamination. We confirm that galaxy interactions enhance AGN activity. However, conditions in the central regions of clusters are inhospitable for AGN activity even if galaxies are in pairs. These results can be explained through models of gas dynamics in which pair interactions stimulate the transfer of gas to the nucleus and clusters suppress gas availability for accretion onto the central black hole.

  6. Changing ionization conditions in SDSS galaxies with active galactic nuclei as a function of environment from pairs to clusters

    Khabiboulline, Emil T.; Steinhardt, Charles L. [California Institute of Technology, 1200 East-California Boulevard, Pasadena, CA 91125 (United States); Silverman, John D. [Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-Shi, Chiba 277-8583 (Japan); Ellison, Sara L. [Department of Physics and Astronomy, University of Victoria, Finnerty Road, Victoria, British Columbia, V8P 1A1 (Canada); Mendel, J. Trevor [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, D-85748 Garching (Germany); Patton, David R., E-mail: ekhabibo@caltech.edu [Department of Physics and Astronomy, Trent University, 1600 West Bank Drive, Peterborough, Ontario, K9J 7B8 (Canada)

    2014-11-01

    We study how active galactic nucleus (AGN) activity changes across environments from galaxy pairs to clusters using 143,843 galaxies with z < 0.2 from the Sloan Digital Sky Survey. Using a refined technique, we apply a continuous measure of AGN activity, characteristic of the ionization state of the narrow-line emitting gas. Changes in key emission-line ratios ([N II] λ6548/Hα, [O III] λ5007/Hβ) between different samples allow us to disentangle different environmental effects while removing contamination. We confirm that galaxy interactions enhance AGN activity. However, conditions in the central regions of clusters are inhospitable for AGN activity even if galaxies are in pairs. These results can be explained through models of gas dynamics in which pair interactions stimulate the transfer of gas to the nucleus and clusters suppress gas availability for accretion onto the central black hole.

  7. Chandra-SDSS Normal and Star-Forming Galaxies. I. X-Ray Source Properties of Galaxies Detected by the Chandra X-Ray Observatory in SDSS DR2

    Hornschemeier, A. E.; Heckman, T. M.; Ptak, A. F.; Tremonti, C. A.; Colbert, E. J. M.

    2005-01-01

    We have cross-correlated X-ray catalogs derived from archival Chandra X-Ray Observatory ACIS observations with a Sloan Digital Sky Survey Data Release 2 (DR2) galaxy catalog to form a sample of 42 serendipitously X-ray-detected galaxies over the redshift interval 0.03galaxies and those in the deepest X-ray surveys. Our chief purpose is to compare optical spectroscopic diagnostics of activity (both star formation and accretion) with X-ray properties of galaxies. Our work supports a normalization value of the X-ray-star formation rate correlation consistent with the lower values published in the literature. The difference is in the allocation of X-ray emission to high-mass X-ray binaries relative to other components, such as hot gas, low-mass X-ray binaries, and/or active galactic nuclei (AGNs). We are able to quantify a few pitfalls in the use of lower resolution, lower signal-to-noise ratio optical spectroscopy to identify X-ray sources (as has necessarily been employed for many X-ray surveys). Notably, we find a few AGNs that likely would have been misidentified as non-AGN sources in higher redshift studies. However, we do not find any X-ray-hard, highly X-ray-luminous galaxies lacking optical spectroscopic diagnostics of AGN activity. Such sources are members of the ``X-ray-bright, optically normal galaxy'' (XBONG) class of AGNs.

  8. CHARACTERIZING THE MID-INFRARED EXTRAGALACTIC SKY WITH WISE AND SDSS

    Yan Lin; Donoso, E.; Tsai, Chao-Wei; Cutri, R.; Jarrett, T.; Stern, D.; Assef, R. J.; Eisenhardt, P.; Blain, A. W.; Stanford, S. A.; Wright, E.; Bridge, C.; Riechers, D. A.

    2013-01-01

    The Wide-field Infrared Survey Explorer (WISE) has completed its all-sky survey in four channels at 3.4-22 μm, detecting hundreds of millions of objects. We merge the WISE mid-infrared data with optical data from the Sloan Digital Sky Survey (SDSS) and provide a phenomenological characterization of WISE extragalactic sources. WISE is most sensitive at 3.4 μm (W1) and least sensitive at 22 μm (W4). The W1 band probes massive early-type galaxies out to z ∼> 1. This is more distant than SDSS identified early-type galaxies, consistent with the fact that 28% of 3.4 μm sources have faint or no r-band counterparts (r > 22.2). In contrast, 92%-95% of 12 μm and 22 μm sources have SDSS optical counterparts with r ≤ 22.2. WISE 3.4 μm detects 89.8% of the entire SDSS QSO catalog at S/N W1 >7σ, but only 18.9% at 22 μm with S/N W4 > 5σ. We show that WISE colors alone are effective in isolating stars (or local early-type galaxies), star-forming galaxies, and strong active galactic nuclei (AGNs)/QSOs at z ∼ 0.8 and W2 –2 . (2) Selection of dust-obscured, type-2 AGN/QSO candidates. We show that WISE W1 – W2 > 0.8, W2 6 (Vega) colors can be used to identify type-2 AGN candidates. The fraction of these type-2 AGN candidates is one-third of all WISE color-selected AGNs. (3) Selection of ultraluminous infrared galaxies (ULIRGs) at z ∼ 2 with extremely red colors, r – W4 > 14 or well-detected 22 μm sources lacking detections in the 3.4 and 4.6 μm bands. The surface density of z ∼ 2 ULIRG candidates selected with r – W4 > 14 is 0.9 ± 0.07 deg –2 at S/N W4 ≥ 5 (the corresponding, lowest flux density of 2.5 mJy), which is consistent with that inferred from smaller area Spitzer surveys. Optical spectroscopy of a small number of these high-redshift ULIRG candidates confirms our selection, and reveals a possible trend that optically fainter or r – W4 redder candidates are at higher redshifts.

  9. Gas flow and dark matter in the inner parts of early-type barred galaxies - I. SPH simulations and comparison with the observed kinematics

    Perez, [No Value; Fux, R; Freeman, K

    This paper presents the dynamical simulations run in the potential derived from the light distribution of 5 late-type barred spiral galaxies (IC 5186, NGC 5728, NGC 7267, NGC 7483 and NGC 5505). The aim is to determine whether the mass distribution together with the hydrodynamical simulations can

  10. SDSS-IV MaNGA: environmental dependence of stellar age and metallicity gradients in nearby galaxies

    Zheng, Zheng; Wang, Huiyuan; Ge, Junqiang; Mao, Shude; Li, Cheng; Li, Ran; Mo, Houjun; Goddard, Daniel; Bundy, Kevin; Li, Hongyu; Nair, Preethi; Lin, Lihwai; Long, R. J.; Riffel, Rogério; Thomas, Daniel; Masters, Karen; Bizyaev, Dmitry; Brownstein, Joel R.; Zhang, Kai; Law, David R.; Drory, Niv; Roman Lopes, Alexandre; Malanushenko, Olena

    2017-03-01

    We present a study on the stellar age and metallicity distributions for 1105 galaxies using the STARLIGHT software on MaNGA (Mapping Nearby Galaxies at APO) integral field spectra. We derive age and metallicity gradients by fitting straight lines to the radial profiles, and explore their correlations with total stellar mass M*, NUV - r colour and environments, as identified by both the large-scale structure (LSS) type and the local density. We find that the mean age and metallicity gradients are close to zero but slightly negative, which is consistent with the inside-out formation scenario. Within our sample, we find that both the age and metallicity gradients show weak or no correlation with either the LSS type or local density environment. In addition, we also study the environmental dependence of age and metallicity values at the effective radii. The age and metallicity values are highly correlated with M* and NUV - r and are also dependent on LSS type as well as local density. Low-mass galaxies tend to be younger and have lower metallicity in low-density environments while high-mass galaxies are less affected by environment.

  11. Alignment between Satellite and Central Galaxies in the SDSS DR7: Dependence on Large-scale Environment

    Wang, Peng; Luo, Yu; Kang, Xi; Libeskind, Noam I.; Wang, Lei; Zhang, Youcai; Tempel, Elmo; Guo, Quan

    2018-06-01

    The alignment between satellites and central galaxies has been studied in detail both in observational and theoretical works. The widely accepted fact is that satellites preferentially reside along the major axis of their central galaxy. However, the origin and large-scale environmental dependence of this alignment are still unknown. In an attempt to determine these variables, we use data constructed from Sloan Digital Sky Survey DR7 to investigate the large-scale environmental dependence of this alignment with emphasis on examining the alignment’s dependence on the color of the central galaxy. We find a very strong large-scale environmental dependence of the satellite–central alignment (SCA) in groups with blue centrals. Satellites of blue centrals in knots are preferentially located perpendicular to the major axes of the centrals, and the alignment angle decreases with environment, namely, when going from knots to voids. The alignment angle strongly depends on the {}0.1(g-r) color of centrals. We suggest that the SCA is the result of a competition between satellite accretion within large-scale structure (LSS) and galaxy evolution inside host halos. For groups containing red central galaxies, the SCA is mainly determined by the evolution effect, while for blue central dominated groups, the effect of the LSS plays a more important role, especially in knots. Our results provide an explanation for how the SCA forms within different large-scale environments. The perpendicular case in groups and knots with blue centrals may also provide insight into understanding similar polar arrangements, such as the formation of the Milky Way and Centaurus A’s satellite system.

  12. The Stellar Initial Mass Function in Early-type Galaxies from Absorption Line Spectroscopy. IV. A Super-Salpeter IMF in the Center of NGC 1407 from Non-parametric Models

    Conroy, Charlie [Department of Astronomy, Harvard University, Cambridge, MA, 02138 (United States); Van Dokkum, Pieter G. [Department of Astronomy, Yale University, New Haven, CT, 06511 (United States); Villaume, Alexa [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2017-03-10

    It is now well-established that the stellar initial mass function (IMF) can be determined from the absorption line spectra of old stellar systems, and this has been used to measure the IMF and its variation across the early-type galaxy population. Previous work focused on measuring the slope of the IMF over one or more stellar mass intervals, implicitly assuming that this is a good description of the IMF and that the IMF has a universal low-mass cutoff. In this work we consider more flexible IMFs, including two-component power laws with a variable low-mass cutoff and a general non-parametric model. We demonstrate with mock spectra that the detailed shape of the IMF can be accurately recovered as long as the data quality is high (S/N ≳ 300 Å{sup −1}) and cover a wide wavelength range (0.4–1.0 μ m). We apply these flexible IMF models to a high S/N spectrum of the center of the massive elliptical galaxy NGC 1407. Fitting the spectrum with non-parametric IMFs, we find that the IMF in the center shows a continuous rise extending toward the hydrogen-burning limit, with a behavior that is well-approximated by a power law with an index of −2.7. These results provide strong evidence for the existence of extreme (super-Salpeter) IMFs in the cores of massive galaxies.

  13. ORBITAL DEPENDENCE OF GALAXY PROPERTIES IN SATELLITE SYSTEMS OF GALAXIES

    Hwang, Ho Seong; Park, Changbom

    2010-01-01

    We study the dependence of satellite galaxy properties on the distance to the host galaxy and the orbital motion (prograde and retrograde orbits) using the Sloan Digital Sky Survey (SDSS) data. From SDSS Data Release 7, we find 3515 isolated satellite systems of galaxies at z -1 . It is found that the radial distribution of early-type satellites in prograde orbit is strongly concentrated toward the host while that of retrograde ones shows much less concentration. We also find the orbital speed of late-type satellites in prograde orbit increases as the projected distance to the host (R) decreases while the speed decreases for those in retrograde orbit. At R less than 0.1 times the host virial radius (R vir,host ), the orbital speed decreases in both prograde and retrograde orbit cases. Prograde satellites are on average fainter than retrograde satellites for both early and late morphological types. The u - r color becomes redder as R decreases for both prograde and retrograde orbit late-type satellites. The differences between prograde and retrograde orbit satellite galaxies may be attributed to their different origin or the different strength of physical processes that they have experienced through hydrodynamic interactions with their host galaxies.

  14. SDSS-IV MaNGA IFS GALAXY SURVEY—SURVEY DESIGN, EXECUTION, AND INITIAL DATA QUALITY

    Yan, Renbin; Zhang, Kai; Bundy, Kevin; Law, David R.; Bershady, Matthew A.; Diamond-Stanic, Aleksandar M.; Andrews, Brett; Cherinka, Brian; Drory, Niv; MacDonald, Nicholas; Sánchez-Gallego, José R.; Thomas, Daniel; Westfall, Kyle B.; Wake, David A.; Weijmans, Anne-Marie; Aragón-Salamanca, Alfonso; Belfiore, Francesco

    2016-01-01

    The MaNGA Survey (Mapping Nearby Galaxies at Apache Point Observatory) is one of three core programs in the Sloan Digital Sky Survey IV. It is obtaining integral field spectroscopy for 10,000 nearby galaxies at a spectral resolution of R  ∼ 2000 from 3622 to 10354 Å. The design of the survey is driven by a set of science requirements on the precision of estimates of the following properties: star formation rate surface density, gas metallicity, stellar population age, metallicity, and abundance ratio, and their gradients; stellar and gas kinematics; and enclosed gravitational mass as a function of radius. We describe how these science requirements set the depth of the observations and dictate sample selection. The majority of targeted galaxies are selected to ensure uniform spatial coverage in units of effective radius (R e ) while maximizing spatial resolution. About two-thirds of the sample is covered out to 1.5 R e (Primary sample), and one-third of the sample is covered to 2.5 R e (Secondary sample). We describe the survey execution with details that would be useful in the design of similar future surveys. We also present statistics on the achieved data quality, specifically the point-spread function, sampling uniformity, spectral resolution, sky subtraction, and flux calibration. For our Primary sample, the median r -band signal-to-noise ratio is ∼70 per 1.4 Å pixel for spectra stacked between 1 R e and 1.5 R e . Measurements of various galaxy properties from the first-year data show that we are meeting or exceeding the defined requirements for the majority of our science goals.

  15. SDSS-IV MaNGA IFS GALAXY SURVEY—SURVEY DESIGN, EXECUTION, AND INITIAL DATA QUALITY

    Yan, Renbin; Zhang, Kai [Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0057 (United States); Bundy, Kevin [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Law, David R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bershady, Matthew A.; Diamond-Stanic, Aleksandar M. [Department of Astronomy, University of Winsconsin-Madison, 475 N. Charter Street, Madison, WI 53706-1582 (United States); Andrews, Brett [Department of Physics and Astronomy and Pittsburgh Particle Physics, Astrophysics and Cosmology Center (PITT PACC), University of Pittsburgh, 3941 OHara Street, Pittsburgh, PA 15260 (United States); Cherinka, Brian [Department of Physics and Astronomy, Johns Hopkins University, Bloomberg Center, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Drory, Niv [McDonald Observatory, University of Texas at Austin, 1 University Station, Austin, TX 78712-0259 (United States); MacDonald, Nicholas; Sánchez-Gallego, José R. [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Thomas, Daniel; Westfall, Kyle B. [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth (United Kingdom); Wake, David A. [Department of Physical Sciences, The Open University, Milton Keynes, MK7 6AA (United Kingdom); Weijmans, Anne-Marie [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Aragón-Salamanca, Alfonso [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Belfiore, Francesco, E-mail: yanrenbin@uky.edu [Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); and others

    2016-12-01

    The MaNGA Survey (Mapping Nearby Galaxies at Apache Point Observatory) is one of three core programs in the Sloan Digital Sky Survey IV. It is obtaining integral field spectroscopy for 10,000 nearby galaxies at a spectral resolution of R  ∼ 2000 from 3622 to 10354 Å. The design of the survey is driven by a set of science requirements on the precision of estimates of the following properties: star formation rate surface density, gas metallicity, stellar population age, metallicity, and abundance ratio, and their gradients; stellar and gas kinematics; and enclosed gravitational mass as a function of radius. We describe how these science requirements set the depth of the observations and dictate sample selection. The majority of targeted galaxies are selected to ensure uniform spatial coverage in units of effective radius (R{sub e}) while maximizing spatial resolution. About two-thirds of the sample is covered out to 1.5 R{sub e} (Primary sample), and one-third of the sample is covered to 2.5 R{sub e} (Secondary sample). We describe the survey execution with details that would be useful in the design of similar future surveys. We also present statistics on the achieved data quality, specifically the point-spread function, sampling uniformity, spectral resolution, sky subtraction, and flux calibration. For our Primary sample, the median r -band signal-to-noise ratio is ∼70 per 1.4 Å pixel for spectra stacked between 1 R{sub e} and 1.5 R{sub e}. Measurements of various galaxy properties from the first-year data show that we are meeting or exceeding the defined requirements for the majority of our science goals.

  16. SDSS-IV MaNGA IFS Galaxy Survey—Survey Design, Execution, and Initial Data Quality

    Yan, Renbin; Bundy, Kevin; Law, David R.; Bershady, Matthew A.; Andrews, Brett; Cherinka, Brian; Diamond-Stanic, Aleksandar M.; Drory, Niv; MacDonald, Nicholas; Sánchez-Gallego, José R.; Thomas, Daniel; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.; Zhang, Kai; Aragón-Salamanca, Alfonso; Belfiore, Francesco; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Brownstein, Joel; Cappellari, Michele; D'Souza, Richard; Emsellem, Eric; Fu, Hai; Gaulme, Patrick; Graham, Mark T.; Goddard, Daniel; Gunn, James E.; Harding, Paul; Jones, Amy; Kinemuchi, Karen; Li, Cheng; Li, Hongyu; Maiolino, Roberto; Mao, Shude; Maraston, Claudia; Masters, Karen; Merrifield, Michael R.; Oravetz, Daniel; Pan, Kaike; Parejko, John K.; Sanchez, Sebastian F.; Schlegel, David; Simmons, Audrey; Thanjavur, Karun; Tinker, Jeremy; Tremonti, Christy; van den Bosch, Remco; Zheng, Zheng

    2016-12-01

    The MaNGA Survey (Mapping Nearby Galaxies at Apache Point Observatory) is one of three core programs in the Sloan Digital Sky Survey IV. It is obtaining integral field spectroscopy for 10,000 nearby galaxies at a spectral resolution of R ˜ 2000 from 3622 to 10354 Å. The design of the survey is driven by a set of science requirements on the precision of estimates of the following properties: star formation rate surface density, gas metallicity, stellar population age, metallicity, and abundance ratio, and their gradients; stellar and gas kinematics; and enclosed gravitational mass as a function of radius. We describe how these science requirements set the depth of the observations and dictate sample selection. The majority of targeted galaxies are selected to ensure uniform spatial coverage in units of effective radius (R e ) while maximizing spatial resolution. About two-thirds of the sample is covered out to 1.5R e (Primary sample), and one-third of the sample is covered to 2.5R e (Secondary sample). We describe the survey execution with details that would be useful in the design of similar future surveys. We also present statistics on the achieved data quality, specifically the point-spread function, sampling uniformity, spectral resolution, sky subtraction, and flux calibration. For our Primary sample, the median r-band signal-to-noise ratio is ˜70 per 1.4 Å pixel for spectra stacked between 1R e and 1.5R e . Measurements of various galaxy properties from the first-year data show that we are meeting or exceeding the defined requirements for the majority of our science goals.

  17. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmic flows and cosmic web from luminous red galaxies

    Ata, Metin; Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Rodríguez-Torres, Sergio; Angulo, Raul E.; Ferraro, Simone; Gil-Marín, Hector; McDonald, Patrick; Hernández Monteagudo, Carlos; Müller, Volker; Yepes, Gustavo; Autefage, Mathieu; Baumgarten, Falk; Beutler, Florian; Brownstein, Joel R.; Burden, Angela; Eisenstein, Daniel J.; Guo, Hong; Ho, Shirley; McBride, Cameron; Neyrinck, Mark; Olmstead, Matthew D.; Padmanabhan, Nikhil; Percival, Will J.; Prada, Francisco; Rossi, Graziano; Sánchez, Ariel G.; Schlegel, David; Schneider, Donald P.; Seo, Hee-Jong; Streblyanska, Alina; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana

    2017-06-01

    We present a Bayesian phase-space reconstruction of the cosmic large-scale matter density and velocity fields from the Sloan Digital Sky Survey-III Baryon Oscillations Spectroscopic Survey Data Release 12 CMASS galaxy clustering catalogue. We rely on a given Λ cold dark matter cosmology, a mesh resolution in the range of 6-10 h-1 Mpc, and a lognormal-Poisson model with a redshift-dependent non-linear bias. The bias parameters are derived from the data and a general renormalized perturbation theory approach. We use combined Gibbs and Hamiltonian sampling, implemented in the argo code, to iteratively reconstruct the dark matter density field and the coherent peculiar velocities of individual galaxies, correcting hereby for coherent redshift space distortions. Our tests relying on accurate N-body-based mock galaxy catalogues show unbiased real space power spectra of the non-linear density field up to k ˜ 0.2 h Mpc-1, and vanishing quadrupoles down to r ˜ 20 h-1 Mpc. We also demonstrate that the non-linear cosmic web can be obtained from the tidal field tensor based on the Gaussian component of the reconstructed density field. We find that the reconstructed velocities have a statistical correlation coefficient compared to the true velocities of each individual light-cone mock galaxy of r ˜ 0.68 including about 10 per cent of satellite galaxies with virial motions (about r = 0.75 without satellites). The power spectra of the velocity divergence agree well with theoretical predictions up to k ˜ 0.2 h Mpc-1. This work will be especially useful to improve, for example, baryon acoustic oscillation reconstructions, kinematic Sunyaev-Zeldovich, integrated Sachs-Wolfe measurements or environmental studies.

  18. SDSS-IV MaNGA - the spatially resolved transition from star formation to quiescence

    Belfiore, Francesco; Maiolino, Roberto; Maraston, Claudia; Emsellem, Eric; Bershady, Matthew A.; Masters, Karen L.; Bizyaev, Dmitry; Boquien, Médéric; Brownstein, Joel R.; Bundy, Kevin; Diamond-Stanic, Aleksandar M.; Drory, Niv; Heckman, Timothy M.; Law, David R.; Malanushenko, Olena; Oravetz, Audrey; Pan, Kaike; Roman-Lopes, Alexandre; Thomas, Daniel; Weijmans, Anne-Marie; Westfall, Kyle B.; Yan, Renbin

    2017-04-01

    Using spatially resolved spectroscopy from SDSS-IV MaNGA we have demonstrated that low ionization emission-line regions (LIERs) in local galaxies result from photoionization by hot evolved stars, not active galactic nuclei, hence tracing galactic region hosting old stellar population where, despite the presence of ionized gas, star formation is no longer occurring. LIERs are ubiquitous in both quiescent galaxies and in the central regions of galaxies where star formation takes place at larger radii. We refer to these two classes of galaxies as extended LIER (eLIER) and central LIER (cLIER) galaxies, respectively. cLIERs are late-type galaxies primarily spread across the green valley, in the transition region between the star formation main sequence and quiescent galaxies. These galaxies display regular disc rotation in both stars and gas, although featuring a higher central stellar velocity dispersion than star-forming galaxies of the same mass. cLIERs are consistent with being slowly quenched inside-out; the transformation is associated with massive bulges, pointing towards the importance of bulge growth via secular evolution. eLIERs are morphologically early types and are indistinguishable from passive galaxies devoid of line emission in terms of their stellar populations, morphology and central stellar velocity dispersion. Ionized gas in eLIERs shows both disturbed and disc-like kinematics. When a large-scale flow/rotation is observed in the gas, it is often misaligned relative to the stellar component. These features indicate that eLIERs are passive galaxies harbouring a residual cold gas component, acquired mostly via external accretion. Importantly, quiescent galaxies devoid of line emission reside in denser environments and have significantly higher satellite fraction than eLIERs. Environmental effects thus represent the likely cause for the existence of line-less galaxies on the red sequence.

  19. An Unusual Transient in the Extremely Metal-Poor Galaxy SDSS J094332.35+332657.6 (Leoncino Dwarf)

    Filho, Mercedes E.; Sánchez Almeida, J.

    2018-05-01

    We have serendipitously discovered that Leoncino Dwarf, an ultra-faint, low-metallicity record-holder dwarf galaxy, may have hosted a transient source, and possibly exhibited a change in morphology, a shift in the center of brightness, and peak variability of the main (host) source in images taken approximately 40 yr apart; it is highly likely that these phenomena are related. Scenarios involving a Solar System object, a stellar cluster, dust enshrouding, and accretion variability have been considered, and discarded, as the origin of the transient. Although a combination of time-varying strong and weak lensing effects, induced by an intermediate mass black hole (104 - 5 × 105 M⊙) moving within the Milky Way halo (0.1 - 4 kpc), can conceivably explain all of the observed variable galaxy properties, it is statistically highly unlikely according to current theoretical predictions, and, therefore, also discarded. A cataclysmic event such as a supernova/hypernova could have occurred, as long as the event was observed towards the later/late-stage descent of the light curve, but this scenario fails to explain the absence of a post-explosion source and/or host HII region in recent optical images. An episode related to the giant eruption of a luminous blue variable star, a stellar merger or a nova, observed at, or near, peak magnitude may explain the transient source and possibly the change in morphology/center of brightness, but can not justify the main source peak variability, unless stellar variability is evoked.

  20. KL Estimation of the Power Spectrum Parameters from the Angular Distribution of Galaxies in Early SDSS Data

    Szalay, Alexander S.; Matsubara, Takahiko; Scranton, Ryan; Vogeley, Michael S.; Connolly, Andrew; Dodelson, Scott; Eisenstein, Daniel; Frieman, Joshua A.; Gunn, James E.; Hui, Lam; Johnston, David; Kent, Stephen M.; Kerscher, Martin; Loveday, Jon; Meiksin, Avery; Narayanan, Vijay; Nichol, Robert C.; O'Connell, Liam; Pope, Adrian; Scoccimarro, Roman; Sheth, Ravi K.; Stebbins, Albert; Strauss, Michael A.; Szapudi, Istvan; Tegmark, Max; Zehavi, Idit; Annis, James; Bahcall, Neta A.; Brinkmann, Jon; Csabai, Istvan; Fukugita, Masataka; Hennessy, Greg; Hogg, David W.; Ivezic, Zeljko; Knapp, Gillian R.; Kunszt, Peter Z.; Lamb, Don Q.; Lee, Brian C.; Lupton, Robert H.; Munn, Jeffrey R.; Peoples, John; Pier, Jeffrey R.; Rockosi, Constance; Schlegel, David; Stoughton, Christopher; Tucker, Douglas L.; Yanny, Brian; York, Donald G.; Szalay, Alexander S.; Jain, Bhuvnesh; Matsubara, Takahiko; Scranton, Ryan; Vogeley, Michael S.; Connolly, Andrew; Dodelson, Scott; Eisenstein, Daniel; Frieman, Joshua A.; Gunn, James E.; Hui, Lam; Johnston, David; Kent, Stephen; Kerscher, Martin; Loveday, Jon; Meiksin, Avery; Narayanan, Vijay; Nichol, Robert C.; Connell, Liam O'; Pope, Adrian; Scoccimarro, Roman; Sheth, Ravi K.; Stebbins, Albert; Strauss, Michael A.; Szapudi, Istvan; Tegmark, Max; Zehavi, Idit

    2002-01-01

    We present measurements of parameters of the 3-dimensional power spectrum of galaxy clustering from 222 square degrees of early imaging data in the Sloan Digital Sky Survey. The projected galaxy distribution on the sky is expanded over a set of Karhunen-Loeve eigenfunctions, which optimize the signal-to-noise ratio in our analysis. A maximum likelihood analysis is used to estimate parameters that set the shape and amplitude of the 3-dimensional power spectrum. Our best estimates are Gamma=0.188 +/- 0.04 and sigma_8L = 0.915 +/- 0.06 (statistical errors only), for a flat Universe with a cosmological constant. We demonstrate that our measurements contain signal from scales at or beyond the peak of the 3D power spectrum. We discuss how the results scale with systematic uncertainties, like the radial selection function. We find that the central values satisfy the analytically estimated scaling relation. We have also explored the effects of evolutionary corrections, various truncations of the KL basis, seeing, sam...

  1. Galaxy Zoo: dust in spiral galaxies

    Masters, Karen L.; Nichol, Robert; Bamford, Steven; Mosleh, Moein; Lintott, Chris J.; Andreescu, Dan; Edmondson, Edward M.; Keel, William C.; Murray, Phil; Raddick, M. Jordan; Schawinski, Kevin; Slosar, Anže; Szalay, Alexander S.; Thomas, Daniel; Vandenberg, Jan

    2010-05-01

    We investigate the effect of dust on spiral galaxies by measuring the inclination dependence of optical colours for 24276 well-resolved Sloan Digital Sky Survey (SDSS) galaxies visually classified via the Galaxy Zoo project. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4mag for the ugri passbands (estimating 0.3mag of extinction in z band). We split the sample into `bulgy' (early-type) and `discy' (late-type) spirals using the SDSS fracdeV (or fDeV) parameter and show that the average face-on colour of `bulgy' spirals is redder than the average edge-on colour of `discy' spirals. This shows that the observed optical colour of a spiral galaxy is determined almost equally by the spiral type (via the bulge-disc ratio and stellar populations), and reddening due to dust. We find that both luminosity and spiral type affect the total amount of extinction, with discy spirals at Mr ~ -21.5mag having the most reddening - more than twice as much as both the lowest luminosity and most massive, bulge-dominated spirals. An increase in dust content is well known for more luminous galaxies, but the decrease of the trend for the most luminous has not been observed before and may be related to their lower levels of recent star formation. We compare our results with the latest dust attenuation models of Tuffs et al. We find that the model reproduces the observed trends reasonably well but overpredicts the amount of u-band attenuation in edge-on galaxies. This could be an inadequacy in the Milky Way extinction law (when applied to external galaxies), but more likely indicates the need for a wider range of dust-star geometries. We end by discussing the effects of dust on large galaxy surveys and emphasize that these effects will become important as we push to higher precision measurements of galaxy properties and their clustering. This publication has been made possible by the participation of more than

  2. Imaging of SDSS z > 6 Quasar Fields: Gravitational Lensing, Companion Galaxies, and the Host Dark Matter Halos

    Willott, Chris J.; Percival, Will J.; McLure, Ross J.; Crampton, David; Hutchings, John B.; Jarvis, Matt J.; Sawicki, Marcin; Simard, Luc

    2005-06-01

    We have undertaken deep optical imaging observations of three 6.2dropouts is consistent with that found in random fields. We consider the expected dark matter halo masses that host these quasars under the assumption that a correlation between black hole mass and dark matter halo mass exists. We show that the steepness of the high-mass tail of the halo mass function at this redshift, combined with realistic amounts of scatter in this correlation, leads to expected halo masses substantially lower than previously believed. This analysis can explain the lack of companion galaxies found here and the low dynamical mass recently published for one of the quasars. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation (NSF) on behalf of the Gemini partnership: the NSF (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).

  3. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample

    Alam, Shadab; Ata, Metin; Bailey, Stephen; Beutler, Florian; Bizyaev, Dmitry; Blazek, Jonathan A.; Bolton, Adam S.; Brownstein, Joel R.; Burden, Angela; Chuang, Chia-Hsun; Comparat, Johan; Cuesta, Antonio J.; Dawson, Kyle S.; Eisenstein, Daniel J.; Escoffier, Stephanie; Gil-Marín, Héctor; Grieb, Jan Niklas; Hand, Nick; Ho, Shirley; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco; Malanushenko, Elena; Malanushenko, Viktor; Maraston, Claudia; McBride, Cameron K.; Nichol, Robert C.; Olmstead, Matthew D.; Oravetz, Daniel; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Pellejero-Ibanez, Marcos; Percival, Will J.; Petitjean, Patrick; Prada, Francisco; Price-Whelan, Adrian M.; Reid, Beth A.; Rodríguez-Torres, Sergio A.; Roe, Natalie A.; Ross, Ashley J.; Ross, Nicholas P.; Rossi, Graziano; Rubiño-Martín, Jose Alberto; Saito, Shun; Salazar-Albornoz, Salvador; Samushia, Lado; Sánchez, Ariel G.; Satpathy, Siddharth; Schlegel, David J.; Schneider, Donald P.; Scóccola, Claudia G.; Seo, Hee-Jong; Sheldon, Erin S.; Simmons, Audrey; Slosar, Anže; Strauss, Michael A.; Swanson, Molly E. C.; Thomas, Daniel; Tinker, Jeremy L.; Tojeiro, Rita; Magaña, Mariana Vargas; Vazquez, Jose Alberto; Verde, Licia; Wake, David A.; Wang, Yuting; Weinberg, David H.; White, Martin; Wood-Vasey, W. Michael; Yèche, Christophe; Zehavi, Idit; Zhai, Zhongxu; Zhao, Gong-Bo

    2017-09-01

    We present cosmological results from the final galaxy clustering data set of the Baryon Oscillation Spectroscopic Survey, part of the Sloan Digital Sky Survey III. Our combined galaxy sample comprises 1.2 million massive galaxies over an effective area of 9329 deg2 and volume of 18.7 Gpc3, divided into three partially overlapping redshift slices centred at effective redshifts 0.38, 0.51 and 0.61. We measure the angular diameter distance DM and Hubble parameter H from the baryon acoustic oscillation (BAO) method, in combination with a cosmic microwave background prior on the sound horizon scale, after applying reconstruction to reduce non-linear effects on the BAO feature. Using the anisotropic clustering of the pre-reconstruction density field, we measure the product DMH from the Alcock-Paczynski (AP) effect and the growth of structure, quantified by fσ8(z), from redshift-space distortions (RSD). We combine individual measurements presented in seven companion papers into a set of consensus values and likelihoods, obtaining constraints that are tighter and more robust than those from any one method; in particular, the AP measurement from sub-BAO scales sharpens constraints from post-reconstruction BAOs by breaking degeneracy between DM and H. Combined with Planck 2016 cosmic microwave background measurements, our distance scale measurements simultaneously imply curvature ΩK = 0.0003 ± 0.0026 and a dark energy equation-of-state parameter w = -1.01 ± 0.06, in strong affirmation of the spatially flat cold dark matter (CDM) model with a cosmological constant (ΛCDM). Our RSD measurements of fσ8, at 6 per cent precision, are similarly consistent with this model. When combined with supernova Ia data, we find H0 = 67.3 ± 1.0 km s-1 Mpc-1 even for our most general dark energy model, in tension with some direct measurements. Adding extra relativistic species as a degree of freedom loosens the constraint only slightly, to H0 = 67.8 ± 1.2 km s-1 Mpc-1. Assuming flat

  4. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: theoretical systematics and Baryon Acoustic Oscillations in the galaxy correlation function

    Vargas-Magaña, Mariana; Ho, Shirley; Cuesta, Antonio J.; O'Connell, Ross; Ross, Ashley J.; Eisenstein, Daniel J.; Percival, Will J.; Grieb, Jan Niklas; Sánchez, Ariel G.; Tinker, Jeremy L.; Tojeiro, Rita; Beutler, Florian; Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Prada, Francisco; Rodríguez-Torres, Sergio A.; Rossi, Graziano; Seo, Hee-Jong; Brownstein, Joel R.; Olmstead, Matthew; Thomas, Daniel

    2018-06-01

    We investigate the potential sources of theoretical systematics in the anisotropic Baryon Acoustic Oscillation (BAO) distance scale measurements from the clustering of galaxies in configuration space using the final Data Release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS). We perform a detailed study of the impact on BAO measurements from choices in the methodology such as fiducial cosmology, clustering estimators, random catalogues, fitting templates, and covariance matrices. The theoretical systematic uncertainties in BAO parameters are found to be 0.002 in the isotropic dilation α and 0.003 in the quadrupolar dilation ɛ. The leading source of systematic uncertainty is related to the reconstruction techniques. Theoretical uncertainties are sub-dominant compared with the statistical uncertainties for BOSS survey, accounting 0.2σstat for α and 0.25σstat for ɛ (σα, stat ˜ 0.010 and σɛ, stat ˜ 0.012, respectively). We also present BAO-only distance scale constraints from the anisotropic analysis of the correlation function. Our constraints on the angular diameter distance DA(z) and the Hubble parameter H(z), including both statistical and theoretical systematic uncertainties, are 1.5 per cent and 2.8 per cent at zeff = 0.38, 1.4 per cent and 2.4 per cent at zeff = 0.51, and 1.7 per cent and 2.6 per cent at zeff = 0.61. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are cross-checked with other BAO analysis in Alam et al. The systematic error budget concerning the methodology on post-reconstruction BAO analysis presented here is used in Alam et al. to produce the final cosmological constraints from BOSS.

  5. Interactions of galaxies outside clusters and massive groups

    Yadav, Jaswant K.; Chen, Xuelei

    2018-06-01

    We investigate the dependence of physical properties of galaxies on small- and large-scale density environment. The galaxy population consists of mainly passively evolving galaxies in comparatively low-density regions of Sloan Digital Sky Survey (SDSS). We adopt (i) local density, ρ _{20}, derived using adaptive smoothing kernel, (ii) projected distance, r_p, to the nearest neighbor galaxy and (iii) the morphology of the nearest neighbor galaxy as various definitions of environment parameters of every galaxy in our sample. In order to detect long-range interaction effects, we group galaxy interactions into four cases depending on morphology of the target and neighbor galaxies. This study builds upon an earlier study by Park and Choi (2009) by including improved definitions of target and neighbor galaxies, thus enabling us to better understand the effect of "the nearest neighbor" interaction on the galaxy. We report that the impact of interaction on galaxy properties is detectable at least up to the pair separation corresponding to the virial radius of (the neighbor) galaxies. This turns out to be mostly between 210 and 360 h^{-1}kpc for galaxies included in our study. We report that early type fraction for isolated galaxies with r_p > r_{vir,nei} is almost ignorant of the background density and has a very weak density dependence for closed pairs. Star formation activity of a galaxy is found to be crucially dependent on neighbor galaxy morphology. We find star formation activity parameters and structure parameters of galaxies to be independent of the large-scale background density. We also exhibit that changing the absolute magnitude of the neighbor galaxies does not affect significantly the star formation activity of those target galaxies whose morphology and luminosities are fixed.

  6. The ATLAS3D project - XX. Mass-size and mass-σ distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function

    Cappellari, Michele; McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, M.; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2013-07-01

    In the companion Paper XV of this series, we derive accurate total mass-to-light ratios (M/L)_JAM≈ (M/L)({r}= {R_e}) within a sphere of radius r= {R_e} centred on the galaxy, as well as stellar (M/L)stars (with the dark matter removed) for the volume-limited and nearly mass-selected (stellar mass M_star ≳ 6× 10^9 { M_{⊙}}) ATLAS3D sample of 260 early-type galaxies (ETGs, ellipticals Es and lenticulars S0s). Here, we use those parameters to study the two orthogonal projections ({M_JAM}, {σ _e}) and ({M_JAM}, {R_e^maj}) of the thin Mass Plane (MP) ({M_JAM}, {σ _e}, {R_e^maj}) which describes the distribution of the galaxy population, where {M_JAM}≡ L× (M/L)_JAM≈ M_star. The distribution of galaxy properties on both projections of the MP is characterized by: (i) the same zone of exclusion (ZOE), which can be transformed from one projection to the other using the scalar virial equation. The ZOE is roughly described by two power laws, joined by a break at a characteristic mass {M_JAM}≈ 3× 10^{10} { M_{⊙}}, which corresponds to the minimum Re and maximum stellar density. This results in a break in the mean {M_JAM}-{σ _e} relation with trends {M_JAM}∝ σ _e^{2.3} and {M_JAM}∝ σ _e^{4.7} at small and large σe, respectively; (ii) a characteristic mass {M_JAM}≈ 2× 10^{11} { M_{⊙}} which separates a population dominated by flat fast rotator with discs and spiral galaxies at lower masses, from one dominated by quite round slow rotators at larger masses; (iii) below that mass the distribution of ETGs' properties on the two projections of the MP tends to be constant along lines of roughly constant σe, or equivalently along lines with {R_e^maj}∝ {M_JAM}, respectively (or even better parallel to the ZOE: {R_e^maj}∝ M_JAM^{0.75}); (iv) it forms a continuous and parallel sequence with the distribution of spiral galaxies; (v) at even lower masses, the distribution of fast-rotator ETGs and late spirals naturally extends to that of dwarf ETGs (Sph

  7. Study of GRBs Hosts Galaxies Vicinity Properties

    Bernal, S.; Vasquez, N.; Hoyle, F.

    2017-07-01

    The study of GRBs host galaxies and its vicinity could provide constrains on the progenitor and an opportunity to use these violent explosions to characterize the nature of the highredshift universe. Studies of GRB host galaxies reveal a population of starforming galaxies with great diversity, spanning a wide range of masses, star formation rate, and redshifts. In order to study the galactic ambient of GRBs we used the S. Savaglio catalog from 2015 where 245 GRBs are listed with RA-Dec position and z. We choose 22 GRBs Hosts galaxies from Savaglio catalog and SDSS DR12, with z range 0population characteristics. We calculate the volumetric density populatation of glalaxies around the GRB Hosts within a volume of an sphere whit radius of 10 h-1 Mpc and find a low density compared with a typical group of galaxies. In order to know the galaxies stellar formation state, in regions where GRBs are formed, we made an analysis of color index using SDSS data of μ [λ 3543], r[λ 6231] and calculate the indexes μ-r. We find a value μ-r=2.63, it means that the galactic ambient of GRBs Host regions are statistically redder than void and wall regions on a indirect way (Voids:μ-r=2.043; Walls:μ-r=2.162). Futhermore, we used a inverse concentration index analysis, ICI=R50/R90 and find that galaxies in GRBs Hosts vicinity are also of slightly early type than void and wall galaxies. With this work we provide characteristics on the regions for future works related with highredsift universe that using the GRBs.

  8. Galaxies

    1981-01-01

    Normal galaxies, radio galaxies, and Seyfert galaxies are considered. The large magellanic cloud and the great galaxy in Andromedia are highlighted. Quasars and BL lacertae objects are also discussed and a review of the spectral observations of all of these galaxies and celestial objects is presented

  9. Stellar Initial Mass Function: Trends With Galaxy Mass And Radius

    Parikh, Taniya

    2017-06-01

    There is currently no consensus about the exact shape and, in particular, the universality of the stellar initial mass function (IMF). For massive galaxies, it has been found that near-infrared (NIR) absorption features, which are sensitive to the ratio of dwarf to giant stars, deviate from a Milky Way-like IMF; their modelling seems to require a larger fraction of low mass stars. There are now increasing results looking at whether the IMF varies not only with galaxy mass, but also radially within galaxies. The SDSS-IV/MaNGA integral-field survey will provide spatially resolved spectroscopy for 10,000 galaxies at R 2000 from 360-1000nm. Spectra of early-type galaxies were stacked to achieve high S/N which is particularly important for features in the NIR. Trends with galaxy radius and mass were compared to stellar population models for a range of absorption features in order to separate degeneracies due to changes in stellar population parameters, such as age, metallicity and element abundances, with potential changes in the IMF. Results for 611 galaxies show that we do not require an IMF steeper than Kroupa as a function of galaxy mass or radius based on the NaI index. The Wing-Ford band hints towards a steeper IMF at large radii however we do not have reliable measurements for the most massive galaxies.

  10. SDSS-IV MaNGA: Star Formation Cessation in Low-redshift Galaxies. I. Dependence on Stellar Mass and Structural Properties

    Wang, Enci; Li, Cheng; Xiao, Ting; Lin, Lin; Bershady, Matthew; Law, David R.; Merrifield, Michael; Sanchez, Sebastian F.; Riffel, Rogemar A.; Riffel, Rogerio; Yan, Renbin

    2018-04-01

    We investigate radial gradients in the recent star formation history (SFH) of 1917 galaxies with 0.01 < z < 0.14 from the Mapping Nearby Galaxies at Apache Point Observatory project. For each galaxy, we obtain two-dimensional maps and radial profiles for three spectroscopically measured parameters that are sensitive to the recent SFH: D n (4000) (the 4000 Å break), EW(Hδ A ), and EW(Hα) (the equivalent width of the Hδ absorption and the Hα emission line). The majority of the spaxels are consistent with models of a continuously declining star formation rate, indicating that starbursts occur rarely in local galaxies with regular morphologies. We classify the galaxies into three classes: fully star-forming (SF), partly quenched (PQ), and totally quenched (TQ). The galaxies that are less massive than 1010 M ⊙ present at most weak radial gradients in the diagnostic parameters. In contrast, massive galaxies with a stellar mass above 1010 M ⊙ present significant gradients in the three diagnostic parameters if they are classified as SF or PQ but show weak gradients in D n (4000) and EW(Hδ A ) and no gradients in EW(Hα) if they are in the TQ class. This implies the existence of a critical stellar mass (∼1010 M ⊙) above which the star formation in a galaxy is shut down from the inside out. Galaxies tend to evolve synchronously from the inner to the outer regions before their mass reaches the critical value. We have further divided the sample at a fixed mass by both bulge-to-total luminosity ratio and morphological type, finding that our conclusions hold regardless of these factors; it appears that the presence of a central dense object is not a driving parameter but rather a by-product of the star formation cessation process.

  11. WISE PHOTOMETRY FOR 400 MILLION SDSS SOURCES

    Lang, Dustin; Hogg, David W.; Schlegel, David J.

    2016-01-01

    We present photometry of images from the Wide-Field Infrared Survey Explorer (WISE) of over 400 million sources detected by the Sloan Digital Sky Survey (SDSS). We use a “forced photometry” technique, using measured SDSS source positions, star–galaxy classification, and galaxy profiles to define the sources whose fluxes are to be measured in the WISE images. We perform photometry with The Tractor image modeling code, working on our “unWISE” coaddds and taking account of the WISE point-spread function and a noise model. The result is a measurement of the flux of each SDSS source in each WISE band. Many sources have little flux in the WISE bands, so often the measurements we report are consistent with zero given our uncertainties. However, for many sources we get 3σ or 4σ measurements; these sources would not be reported by the “official” WISE pipeline and will not appear in the WISE catalog, yet they can be highly informative for some scientific questions. In addition, these small-signal measurements can be used in stacking analyses at the catalog level. The forced photometry approach has the advantage that we measure a consistent set of sources between SDSS and WISE, taking advantage of the resolution and depth of the SDSS images to interpret the WISE images; objects that are resolved in SDSS but blended together in WISE still have accurate measurements in our photometry. Our results, and the code used to produce them, are publicly available at http://unwise.me

  12. STAR FORMATION AT Z = 2.481 IN THE LENSED GALAXY SDSS J1110+6459: STAR FORMATION DOWN TO 30 PARSEC SCALES.

    Johnson, Traci L; Rigby, Jane R; Sharon, Keren; Gladders, Michael D; Florian, Michael; Bayliss, Matthew B; Wuyts, Eva; Whitaker, Katherine E; Livermore, Rachael; Murray, Katherine T

    2017-07-10

    We present measurements of the surface density of star formation, the star-forming clump luminosity function, and the clump size distribution function, for the lensed galaxy SGAS J111020.0+645950.8 at a redshift of z =2.481. The physical size scales that we probe, radii r = 30-50 pc, are considerably smaller scales than have yet been studied at these redshifts. The star formation surface density we find within these small clumps is consistent with surface densities measured previously for other lensed galaxies at similar redshift. Twenty-two percent of the rest-frame ultraviolet light in this lensed galaxy arises from small clumps, with r star-forming regions smaller than 100 pc-physical scales not usually resolved at these redshifts by current telescopes-are important locations of star formation in the distant universe. If this galaxy is representative, this may contradict the theoretical picture in which the critical size scale for star formation in the distant universe is of order 1 kiloparsec. Instead, our results suggest that current telescopes have not yet resolved the critical size scales of star-forming activity in galaxies over most of cosmic time.

  13. Galaxies

    1989-01-01

    In studies of the large scale structure of the universe there is a continuing need for extensive galaxy redshift determinations. Optically selected redshift surveys are of particular importance, since flux-limited samples record much higher space densities of galaxies than samples of similar size selected in other wavebands. A considerable amount of the South African Astronomical Observatory (SAAO) observing time is currently being devoted to carrying out a large southern galaxy redshift survey. A recently completed study, the Durham-SAAO redshift survey suggests that the mean density of matter is well below the critical limit for a closed universe and also that the universe may be homogenous at very large scales. Other research conducted by the SAAO include studies on: the distribution of galaxies; Seyfert galaxies; starburst and IRAS galaxies; interacting and compact galaxies; a re-evaluation of the Cepheid distance to NGC 300, and a search for quasars behind galaxies. 1 fig

  14. Galaxies

    1987-01-01

    The size and nature of any large-scale anisotropy in the three-dimensional distribution of galaxies is still little understood. Recent studies have indicated that large fluctuations in the matter distribution on a scale from tens up to several hundreds of megaparsecs may exist. Work at the South African Astronomical Observatory (SAAO) in recent years has made major contributions to studies of the large scale distribution of galaxies, as well as to solving the problems of the galactic and extragalactic distance scale. Other studies of galaxies undertaken at SAAO include: quasars in the fields of nearby galaxies; dwarf irregular galaxies; IRAS galaxies; Seyfert galaxies; 'hot spot' galaxies; supernovae in NGC 5128 and NGC 1559 and superclusters. 4 figs

  15. SDSS-IV MaNGA-resolved Star Formation and Molecular Gas Properties of Green Valley Galaxies: A First Look with ALMA and MaNGA

    Lin, Lihwai; Belfiore, Francesco; Pan, Hsi-An; Bothwell, M. S.; Hsieh, Pei-Ying; Huang, Shan; Xiao, Ting; Sánchez, Sebastián F.; Hsieh, Bau-Ching; Masters, Karen; Ramya, S.; Lin, Jing-Hua; Hsu, Chin-Hao; Li, Cheng; Maiolino, Roberto; Bundy, Kevin; Bizyaev, Dmitry; Drory, Niv; Ibarra-Medel, Héctor; Lacerna, Ivan; Haines, Tim; Smethurst, Rebecca; Stark, David V.; Thomas, Daniel

    2017-12-01

    We study the role of cold gas in quenching star formation in the green valley by analyzing ALMA 12CO (1-0) observations of three galaxies with resolved optical spectroscopy from the MaNGA survey. We present resolution-matched maps of the star formation rate and molecular gas mass. These data are used to calculate the star formation efficiency (SFE) and gas fraction ({f}{gas}) for these galaxies separately in the central “bulge” regions and outer disks. We find that, for the two galaxies whose global specific star formation rate (sSFR) deviates most from the star formation main sequence, the gas fraction in the bulges is significantly lower than that in their disks, supporting an “inside-out” model of galaxy quenching. For the two galaxies where SFE can be reliably determined in the central regions, the bulges and disks share similar SFEs. This suggests that a decline in {f}{gas} is the main driver of lowered sSFR in bulges compared to disks in green valley galaxies. Within the disks, there exist common correlations between the sSFR and SFE and between sSFR and {f}{gas} on kiloparsec scales—the local SFE or {f}{gas} in the disks declines with local sSFR. Our results support a picture in which the sSFR in bulges is primarily controlled by {f}{gas}, whereas both SFE and {f}{gas} play a role in lowering the sSFR in disks. A larger sample is required to confirm if the trend established in this work is representative of the green valley as a whole.

  16. Dense Cores in Galaxies Out to z = 2.5 in SDSS, UltraVISTA, and the Five 3D-HST/CANDELS Fields

    van Dokkum, Pieter G.; Bezanson, Rachel; van der Wel, Arjen; Nelson, Erica June; Momcheva, Ivelina; Skelton, Rosalind E.; Whitaker, Katherine E.; Brammer, Gabriel; Conroy, Charlie; Förster Schreiber, Natascha M.; Fumagalli, Mattia; Kriek, Mariska; Labbé, Ivo; Leja, Joel; Marchesini, Danilo; Muzzin, Adam; Oesch, Pascal; Wuyts, Stijn

    2014-08-01

    The dense interiors of massive galaxies are among the most intriguing environments in the universe. In this paper,we ask when these dense cores were formed and determine how galaxies gradually assembled around them. We select galaxies that have a stellar mass >3 × 1010 M ⊙ inside r = 1 kpc out to z = 2.5, using the 3D-HST survey and data at low redshift. Remarkably, the number density of galaxies with dense cores appears to have decreased from z = 2.5 to the present. This decrease is probably mostly due to stellar mass loss and the resulting adiabatic expansion, with some contribution from merging. We infer that dense cores were mostly formed at z > 2.5, consistent with their largely quiescent stellar populations. While the cores appear to form early, the galaxies in which they reside show strong evolution: their total masses increase by a factor of 2-3 from z = 2.5 to z = 0 and their effective radii increase by a factor of 5-6. As a result, the contribution of dense cores to the total mass of the galaxies in which they reside decreases from ~50% at z = 2.5 to ~15% at z = 0. Because of their early formation, the contribution of dense cores to the total stellar mass budget of the universe is a strong function of redshift. The stars in cores with M 1 kpc > 3 × 1010 M ⊙ make up ~0.1% of the stellar mass density of the universe today but 10%-20% at z ~ 2, depending on their initial mass function. The formation of these cores required the conversion of ~1011 M ⊙ of gas into stars within ~1 kpc, while preventing significant star formation at larger radii.

  17. Analysis of the star formation histories of galaxies in different environments: from low to high density

    Ortega-Minakata, René A.

    2015-11-01

    formation histories of galaxies in our catalogue were found to be strongly dependent on their morphology, and consequently on their emission-line activity. Star-forming galaxies are late types that have the youngest populations; Sy2-dominated galaxies show a mixture of young and old populations, while LINER-likes have older populations; and passive, early-type galaxies have the oldest populations and have no current star formation. This is consistent with the idea that the processes that fix or change the morphology of galaxies are more internal and modulated by their mass, and are tightly related to how much gas is available to stimulate or stop star formation or AGN activity. In contrast, the star formation histories of galaxies were found to be only weakly dependent on their environmental density, with isolated galaxies showing somewhat younger populations than galaxies in high-density environments. This is consistent with the weak morphology-density relation found for the general population of galaxies, and supports the idea that morphology and formation history are tightly related and, while the processes that change the morphology are more common in the cluster environment, the environmental density itself does not directly affect much the formation history of galaxies. The stellar mass of galaxies seems to modulate their activity and morphology: massive galaxies formed more rapidly in the past, efficiently converting their gas into stars, leaving little or no gas to form stars or fuel AGN activity later on, thus making them low-intensity active galaxies or passive galaxies. The formation of these massive galaxies would then only depend on the local density of protogalaxies, so a high merger rate in environments similar to compact groups of galaxies in the past would result in an early-type galaxy, effectively explaining the relation between mass, activity, morphology, stellar mean age and velocity dispersion of galaxies. The catalogue presented here is useful and

  18. Cosmological parameters from SDSS and WMAP

    Tegmark, Max; Strauss, Michael A.; Bahcall, Neta A.; Schlegel, David; Finkbeiner, Douglas; Gunn, James E.; Ostriker, Jeremiah P.; Seljak, Uros; Ivezic, Zeljko; Knapp, Gillian R.; Lupton, Robert H.; Blanton, Michael R.; Scoccimarro, Roman; Hogg, David W.; Abazajian, Kevork; Xu Yongzhong; Dodelson, Scott; Sandvik, Havard; Wang Xiaomin; Jain, Bhuvnesh

    2004-01-01

    We measure cosmological parameters using the three-dimensional power spectrum P(k) from over 200 000 galaxies in the Sloan Digital Sky Survey (SDSS) in combination with Wilkinson Microwave Anisotropy Probe (WMAP) and other data. Our results are consistent with a 'vanilla' flat adiabatic cold dark matter model with a cosmological constant without tilt (n s =1), running tilt, tensor modes, or massive neutrinos. Adding SDSS information more than halves the WMAP-only error bars on some parameters, tightening 1σ constraints on the Hubble parameter from h≅0.74 -0.07 +0.18 to h≅0.70 -0.03 +0.04 , on the matter density from Ω m ≅0.25±0.10 to Ω m ≅0.30±0.04 (1σ) and on neutrino masses from 0 ≅16.3 -1.8 +2.3 Gyr to t 0 ≅14.1 -0.9 +1.0 Gyr by adding SDSS and SN Ia data. Including tensors, running tilt, neutrino mass and equation of state in the list of free parameters, many constraints are still quite weak, but future cosmological measurements from SDSS and other sources should allow these to be substantially tightened

  19. Cross-calibration of CO- vs dust-based gas masses and assessment of the dynamical mass budget in Herschel-SDSS Stripe82 galaxies

    Bertemes, Caroline; Wuyts, Stijn; Lutz, Dieter; Förster Schreiber, Natascha M.; Genzel, Reinhard; Minchin, Robert F.; Mundell, Carole G.; Rosario, David; Saintonge, Amélie; Tacconi, Linda

    2018-05-01

    We present a cross-calibration of CO- and dust-based molecular gas masses at z ≤ 0.2. Our results are based on a survey with the IRAM 30-m telescope collecting CO(1-0) measurements of 78 massive (log M⋆/M⊙ > 10) galaxies with known gas-phase metallicities, and with IR photometric coverage from WISE (22 μ ) and Herschel SPIRE (250, 350, 500μ). We find a tight relation (˜0.17 dex scatter) between the gas masses inferred from CO and dust continuum emission, with a minor systematic offset of 0.05 dex. The two methods can be brought into agreement by applying a metallicity-dependent adjustment factor (˜0.13 dex scatter). We illustrate that the observed offset is consistent with a scenario in which dust traces not only molecular gas, but also part of the H I reservoir, residing in the H2 -dominated region of the galaxy. Observations of the CO(2-1) to CO(1-0) line ratio for two thirds of the sample indicate a narrow range in excitation properties, with a median ratio of luminosities ⟨R21⟩ ˜ 0.64. Finally, we find dynamical mass constraints from spectral line profile fitting to agree well with the anticipated mass budget enclosed within an effective radius, once all mass components (stars, gas and dark matter) are accounted for.

  20. Predicting Galaxy Star Formation Rates via the Co-evolution of Galaxies and Halos

    Watson, Douglas F.; Hearin, Andrew P.; Berlind, Andreas A.; Becker, Matthew R.; Behroozi, Peter S.; Skibba, Ramin A.; Reyes, Reinabelle; Zentner, Andrew R.; Bosch, Frank C. van den

    2014-01-01

    In this paper, we test the age matching hypothesis that the star formation rate (SFR) of a galaxy of fixed stellar mass is determined by its dark matter halo formation history, and as such, that more quiescent galaxies reside in older halos. This simple model has been remarkably successful at predicting color-based galaxy statistics at low redshift as measured in the Sloan Digital Sky Survey (SDSS). To further test this method with observations, we present new SDSS measurements of the galaxy ...

  1. Understanding the nature of luminous red galaxies (LRGs): connecting LRGs to central and satellite subhaloes

    Masaki, Shogo; Hikage, Chiaki; Takada, Masahiro; Spergel, David N.; Sugiyama, Naoshi

    2013-08-01

    We develop a novel abundance matching method to construct a mock catalogue of luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS), using catalogues of haloes and subhaloes in N-body simulations for a Λ-dominated cold dark matter model. Motivated by observations suggesting that LRGs are passively evolving, massive early-type galaxies with a typical age ≳5 Gyr, we assume that simulated haloes at z = 2 (z2-halo) are progenitors for LRG-host subhaloes observed today, and we label the most tightly bound particles in each progenitor z2-halo as LRG `stars'. We then identify the subhaloes containing these stars to z = 0.3 (SDSS redshift) in descending order of the masses of z2-haloes until the comoving number density of the matched subhaloes becomes comparable to the measured number density of SDSS LRGs, bar{n}_LRG=10^{-4} h^3 Mpc^{-3}. Once the above prescription is determined, our only free parameter is the number density of haloes identified at z = 2 and this parameter is fixed to match the observed number density at z = 0.3. By tracing subsequent merging and assembly histories of each progenitor z2-halo, we can directly compute, from the mock catalogue, the distributions of central and satellite LRGs and their internal motions in each host halo at z = 0.3. While the SDSS LRGs are galaxies selected by the magnitude and colour cuts from the SDSS images and are not necessarily a stellar-mass-selected sample, our mock catalogue reproduces a host of SDSS measurements: the halo occupation distribution for central and satellite LRGs, the projected autocorrelation function of LRGs, the cross-correlation of LRGs with shapes of background galaxies (LRG-galaxy weak lensing) and the non-linear redshift-space distortion effect, the Finger-of-God effect, in the angle-averaged redshift-space power spectrum. The mock catalogue generated based on our method can be used for removing or calibrating systematic errors in the cosmological interpretation of LRG clustering

  2. GALEX-SDSS CATALOGS FOR STATISTICAL STUDIES

    Budavari, Tamas; Heinis, Sebastien; Szalay, Alexander S.; Nieto-Santisteban, Maria; Bianchi, Luciana; Gupchup, Jayant; Shiao, Bernie; Smith, Myron; Chang Ruixiang; Kauffmann, Guinevere; Morrissey, Patrick; Wyder, Ted K.; Martin, D. Christopher; Barlow, Tom A.; Forster, Karl; Friedman, Peter G.; Schiminovich, David; Milliard, Bruno; Donas, Jose; Seibert, Mark

    2009-01-01

    We present a detailed study of the Galaxy Evolution Explorer's (GALEX) photometric catalogs with special focus on the statistical properties of the All-sky and Medium Imaging Surveys. We introduce the concept of primaries to resolve the issue of multiple detections and follow a geometric approach to define clean catalogs with well understood selection functions. We cross-identify the GALEX sources (GR2+3) with Sloan Digital Sky Survey (SDSS; DR6) observations, which indirectly provides an invaluable insight into the astrometric model of the UV sources and allows us to revise the band merging strategy. We derive the formal description of the GALEX footprints as well as their intersections with the SDSS coverage along with analytic calculations of their areal coverage. The crossmatch catalogs are made available for the public. We conclude by illustrating the implementation of typical selection criteria in SQL for catalog subsets geared toward statistical analyses, e.g., correlation and luminosity function studies.

  3. The ATLAS(3D) project - XX. Mass-size and mass-Sigma distributions of early-type galaxies : bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function

    Cappellari, Michele; McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frederic; Bureau, M.; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnovic, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2013-01-01

    In the companion Paper XV of this series, we derive accurate total mass-to-light ratios (M/L)(JAM) approximate to (M/L)(r = R-e) within a sphere of radius r = R-e centred on the galaxy, as well as stellar (M/L)(stars) (with the dark matter removed) for the volume-limited and nearly mass-selected

  4. Cross-correlation of SDSS DR7 quasars and DR10 BOSS galaxies: The weak luminosity dependence of quasar clustering at z ∼ 0.5

    Shen, Yue; McBride, Cameron K.; Swanson, Molly E. C.; White, Martin; Kirkpatrick, Jessica A.; Ross, Nicholas P.; Schlegel, David J.; Zheng, Zheng; Myers, Adam D.; Guo, Hong; Zehavi, Idit; Padmanabhan, Nikhil; Parejko, John K.; Schneider, Donald P.; Streblyanska, Alina; Pan, Kaike; Bizyaev, Dmitry; Brewington, Howard; Ebelke, Garrett; Malanushenko, Viktor

    2013-01-01

    We present the measurement of the two-point cross-correlation function (CCF) of 8198 Sloan Digital Sky Survey Data Release 7 quasars and 349,608 Data Release 10 CMASS galaxies from the Baryonic Oscillation Spectroscopic Survey at 0.3 < z < 0.9. The CCF can be reasonably well fit by a power-law model ξ QG (r) = (r/r 0 ) –γ on projected scales of r p = 2-25 h –1 Mpc with r 0 = 6.61 ± 0.25 h –1 Mpc and γ = 1.69 ± 0.07. We estimate a quasar linear bias of b Q = 1.38 ± 0.10 at (z) = 0.53 from the CCF measurements, which corresponds to a characteristic host halo mass of ∼4 × 10 12 h –1 M ☉ , compared with a ∼10 13 h –1 M ☉ characteristic host halo mass for CMASS galaxies. Based on the clustering measurements, most quasars at z-bar ∼0.5 are not the descendants of their higher luminosity counterparts at higher redshift, which would have evolved into more massive and more biased systems at low redshift. We divide the quasar sample in luminosity and constrain the luminosity dependence of quasar bias to be db Q /dlog L = 0.20 ± 0.34 or 0.11 ± 0.32 (depending on different luminosity divisions) for quasar luminosities –23.5 > M i (z = 2) > –25.5, implying a weak luminosity dependence of clustering for luminous quasars at z-bar ∼0.5. We compare our measurements with theoretical predictions, halo occupation distribution (HOD) models, and mock catalogs. These comparisons suggest that quasars reside in a broad range of host halos. The host halo mass distributions significantly overlap with each other for quasars at different luminosities, implying a poor correlation between halo mass and instantaneous quasar luminosity. We also find that the quasar HOD parameterization is largely degenerate such that different HODs can reproduce the CCF equally well, but with different satellite fractions and host halo mass distributions. These results highlight the limitations and ambiguities in modeling the distribution of quasars with the standard HOD approach.

  5. Dark Galaxies and Lost Baryons (IAU S244)

    Davies, Jonathan I.; Disney, Michael J.

    2008-05-01

    ; Numerical simulation of the dwarf companions of giant galaxies A. Nelson and P. Williams; Delayed galaxies C. Struck, M. Hancock, B. Smith, P. Appleton, V. Charmandaris and M. Giroux; Probe of dark galaxies via disturbed/lopsided isolated galaxies I. Karachentsev, V. Karachentseva, W. Huchtmeier, D. Makarov and S. Kaisin; Star formation thresholds J. Schaye; Scaling relations of dwarf galaxies without supernova-driven winds K. Tassis, A. Kravtsov and N. Gnedin; Star formation in massive low surface brightness galaxies K. O'Neil; Linking clustering properties and the evolution of low surface brightness galaxies D. Bomans and S. Rosenbaum; Too small to form a galaxy: how the UV background determines the baryon fraction M. Hoeft, G. Yepes and S. Gottlober; Star formation in damped Lyman selected galaxies L. Christensen; Dark-matter content of early-type galaxies with planetary nebulae N. Napolitano et al.; Hunting for ghosts: low surface brightnesses from pixels R. Scaramella and S. Sabatini; Baryonic properties of the darkest galaxies E. Grebel; The dwarf low surface brightness population in different environments of the local universe S. Sabatini, J. Davies, S. Roberts and R. Scaramella; Mass modelling of dwarf spheroidal galaxies J. Klimentowski et al.; Evolution of dwarf galaxies in the Centaurus A Group L. Makarova and D. Makarov; A flat faint end of the Fornax cluster galaxy luminosity function S. Mieske, M. Hilker, L. Infante and C. Mendes de Oliveira; Can massive dark halos destroy the discs of dwarf galaxies? B. Fuchs and O. Esquivel; 'Dark galaxies' and local very metal-poor gas-rich galaxies: possible interrelations S. Pustilnik; Morphology and environment of dwarf galaxies in the local universe H. Ann; Arecibo survey of HI emission from disk galaxies at redshift z 0.2 B. Catinella, M. Haynes, J. Gardner, A. Connolly and R. Giovanelli; AGES observations of

  6. Stellar mass estimation based on IRAC photometry for Spitzer SWIRE-field galaxies

    Zhu Yinan; Wu Hong; Li Haining; Cao Chen

    2010-01-01

    We analyze the feasibility of estimating the stellar mass of galaxies by mid-infrared luminosities based on a large sample of galaxies cross-identified from Spitzer SWIRE fields and the SDSS spectrographic survey. We derived the formulae to calculate the stellar mass by using IRAC 3.6 μm and 4.5 μm luminosities. The mass-to-luminosity ratios of IRAC 3.6 μm and 4.5 μm luminosities are more sensitive to the star formation history of galaxies than to other factors, such as the intrinsic extinction, metallicity and star formation rate. To remove the effect of star formation history, we used g - r color to recalibrate the formulae and obtain a better result. Researchers must be more careful when estimating the stellar mass of low metallicity galaxies using our formulae. Due to the emission from dust heated by the hottest young stars, luminous infrared galaxies present higher IRAC 4.5 μm luminosities compared to IRAC 3.6 μm luminosities. For most of type-II AGNs, the nuclear activity cannot enhance 3.6 μm and 4.5 μm luminosities compared with normal galaxies. Star formation in our AGN-hosting galaxies is also very weak, almost all of which are early-type galaxies.

  7. Detection of baryon acoustic oscillation features in the large-scale three-point correlation function of SDSS BOSS DR12 CMASS galaxies

    Slepian, Zachary; Eisenstein, Daniel J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Gil-Marín, Héctor; Ho, Shirley; Kitaura, Francisco-Shu; Percival, Will J.; Ross, Ashley J.; Rossi, Graziano; Seo, Hee-Jong; Slosar, Anže; Vargas-Magaña, Mariana

    2017-08-01

    We present the large-scale three-point correlation function (3PCF) of the Sloan Digital Sky Survey DR12 Constant stellar Mass (CMASS) sample of 777 202 Luminous Red Galaxies, the largest-ever sample used for a 3PCF or bispectrum measurement. We make the first high-significance (4.5σ) detection of baryon acoustic oscillations (BAO) in the 3PCF. Using these acoustic features in the 3PCF as a standard ruler, we measure the distance to z = 0.57 to 1.7 per cent precision (statistical plus systematic). We find DV = 2024 ± 29 Mpc (stat) ± 20 Mpc (sys) for our fiducial cosmology (consistent with Planck 2015) and bias model. This measurement extends the use of the BAO technique from the two-point correlation function (2PCF) and power spectrum to the 3PCF and opens an avenue for deriving additional cosmological distance information from future large-scale structure redshift surveys such as DESI. Our measured distance scale from the 3PCF is fairly independent from that derived from the pre-reconstruction 2PCF and is equivalent to increasing the length of BOSS by roughly 10 per cent; reconstruction appears to lower the independence of the distance measurements. Fitting a model including tidal tensor bias yields a moderate-significance (2.6σ) detection of this bias with a value in agreement with the prediction from local Lagrangian biasing.

  8. SDSS-IV MaNGA: What Shapes the Distribution of Metals in Galaxies? Exploring the Roles of the Local Gas Fraction and Escape Velocity

    Barrera-Ballesteros, J. K.; Heckman, T.; Sánchez, S. F.; Zakamska, N. L.; Cleary, J.; Zhu, G.; Brinkmann, J.; Drory, N.; THE MaNGA TEAM

    2018-01-01

    We determine the local metallicity of the ionized gas for more than 9.2 × 105 star-forming regions (spaxels) located in 1023 nearby galaxies included in the Sloan Digital Sky Survey-IV MaNGA integral field spectroscopy unit survey. We use the dust extinction derived from the Balmer decrement and the stellar template fitting in each spaxel to estimate the local gas and stellar mass densities, respectively. We also use the measured rotation curves to determine the local escape velocity (V esc). We then analyze the relationships between the local metallicity and both the local gas fraction (μ) and V esc. We find that metallicity decreases with both increasing μ and decreasing V esc. By examining the residuals in these relations we show that the gas fraction plays a more primary role in the local chemical enrichment than does V esc. We show that the gas-regulator model of chemical evolution provides a reasonable explanation of the metallicity on local scales. The best-fit parameters for this model are consistent with the metal loss caused by momentum-driven galactic outflows. We also argue that both the gas fraction and the local escape velocity are connected to the local stellar surface density, which in turn is a tracer of the epoch at which the dominant local stellar population formed.

  9. Discovery of four gravitational lensing systems by clusters in the SDSS DR6

    Wen Zhonglue; Han Jinlin; Xu Xiangyang; Jiang Yunying; Guo Zhiqing; Wang Pengfei; Liu Fengshan

    2009-01-01

    We report the discovery of 4 strong gravitational lensing systems by visual inspections of the Sloan Digital Sky Survey images of galaxy clusters in Data Release 6 (SDSS DR6). Two of the four systems show Einstein rings while the others show tangential giant arcs. These arcs or rings have large angular separations (> 8) from the bright central galaxies and show bluer color compared with the red cluster galaxies. In addition, we found 5 probable and 4 possible lenses by galaxy clusters. (letters)

  10. Selections from 2017: Mapping the Universe with SDSS-IV

    Kohler, Susanna

    2017-12-01

    Editors note:In these last two weeks of 2017, well be looking at a few selections that we havent yet discussed on AAS Nova from among the most-downloaded paperspublished in AAS journals this year. The usual posting schedule will resume in January.Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant UniversePublished June2017Main takeaway:The incredibly prolific Sloan Digital Sky Survey has provided photometric observations of around 500 million objects and spectra for more than 3 million objects. The survey has now entered its fourth iteration, SDSS-IV, with the first public data release made in June 2016. A publication led by Michael Blanton (New York University) describes the facilities used for SDSS-IV, its science goals, and itsthree coreprograms.Why its interesting:Since data collection began in 2000, SDSS has been one of the premier surveysproviding imaging and spectroscopy for objects in both the near and distant universe.SDSS has measured spectra not only for the stars in our own Milky Way, but also for galaxies that lie more than 7 billion light-years distant making itan extremelyuseful and powerful tool for mapping our universe.What SDSS-IV is looking for:SDSS image of an example MaNGA target galaxy (left), with some of the many things we can learn about it shown in the right and bottom panels: stellar velocity dispersion, stellar mean velocity, stellar population age, metallicity, etc. [Blanton et al. 2017]SDSS-IV containsthree core programs:Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2)provides high-resolution near-infrared spectra of hundreds of thousands of Milky-Way stars with the goal ofimproving our understanding of the history of the Milky Way and of stellar astrophysics.Mapping Nearby Galaxies at Apache Point Observatory (MaNGA)obtains spatially resolved spectra for thousands of nearby galaxiesto better understand the evolutionary histories of galaxies and what regulates their star formation

  11. Uv-bright Nearby Early-type Galaxies Observed in the Mid-infrared: Eidence for a Multi-stage Formation History by Way of WISE and GALEX Imaging

    Petty, S. M.; Neill, J. D.; Jarrett, T. H.; Blain, A. W.; Farrah, D. G.; Rich, R. M.; Tsai, C.-W.; Benford, D. J.; Bridge, C. R.; Lake, S. E.; hide

    2013-01-01

    In the local universe, 10% of massive elliptical galaxies are observed to exhibit a peculiar property: a substantial excess of ultraviolet emission than what is expected from their old, red stellar populations. Several origins for this ultraviolet excess (UVX) have been proposed including a population of hot young stars and a population of old, blue horizontal branch or extended horizontal branch (BHB or EHB) stars that have undergone substantial mass loss from their outer atmospheres. We explore the radial distribution of UVX in a selection of 49 nearby E/S0-type galaxies by measuring their extended photometry in the UV through mid-infrared (mid-IR) with the Galaxy Evolution Explorer (GALEX), the Sloan Digital Sky Survey, and the Wide-field Infrared Survey Explorer (WISE). We compare UV/optical and UV/mid-IR colors with the Flexible Stellar Population Synthesis models, which allow for the inclusion of EHB stars. We find that combined WISE mid-IR and GALEX UV colors are more effective in distinguishing models than optical colors, and that the UV/mid-IR combination is sensitive to the EHB fraction. There are strong color gradients, with the outer radii bluer than the inner half-light radii by approx.1 mag. This color difference is easily accounted for with an increase in the BHB fraction of 0.25 with radius. We estimated that the average ages for the inner and outer radii are 7.0 +/- 0.3 Gyr, and 6.2 +/- 0.2 Gyr, respectively, with the implication that the outer regions are likely to have formed approx. 1 Gyr after the inner regions. Additionally, we find that metallicity gradients are likely not a significant factor in the color difference. The separation of color between the inner and outer regions, which agrees with a specific stellar population difference (e.g., higher EHB populations), and the approx. 0.5-2 Gyr age difference suggests multi-stage formation. Our results are best explained by inside-out formation: rapid star formation within the core at early

  12. UV-BRIGHT NEARBY EARLY-TYPE GALAXIES OBSERVED IN THE MID-INFRARED: EVIDENCE FOR A MULTI-STAGE FORMATION HISTORY BY WAY OF WISE AND GALEX IMAGING

    Petty, S. M.; Farrah, D. G.; Neill, J. D.; Bridge, C. R.; Jarrett, T. H.; Tsai, C.-W.; Blain, A. W.; Rich, R. M.; Lake, S. E.; Wright, E. L.; Benford, D. J.; Masci, F. J.

    2013-01-01

    In the local universe, 10% of massive elliptical galaxies are observed to exhibit a peculiar property: a substantial excess of ultraviolet emission than what is expected from their old, red stellar populations. Several origins for this ultraviolet excess (UVX) have been proposed including a population of hot young stars and a population of old, blue horizontal branch or extended horizontal branch (BHB or EHB) stars that have undergone substantial mass loss from their outer atmospheres. We explore the radial distribution of UVX in a selection of 49 nearby E/S0-type galaxies by measuring their extended photometry in the UV through mid-infrared (mid-IR) with the Galaxy Evolution Explorer (GALEX), the Sloan Digital Sky Survey, and the Wide-field Infrared Survey Explorer (WISE). We compare UV/optical and UV/mid-IR colors with the Flexible Stellar Population Synthesis models, which allow for the inclusion of EHB stars. We find that combined WISE mid-IR and GALEX UV colors are more effective in distinguishing models than optical colors, and that the UV/mid-IR combination is sensitive to the EHB fraction. There are strong color gradients, with the outer radii bluer than the inner half-light radii by ∼1 mag. This color difference is easily accounted for with an increase in the BHB fraction of 0.25 with radius. We estimated that the average ages for the inner and outer radii are 7.0 ± 0.3 Gyr, and 6.2 ± 0.2 Gyr, respectively, with the implication that the outer regions are likely to have formed ∼1 Gyr after the inner regions. Additionally, we find that metallicity gradients are likely not a significant factor in the color difference. The separation of color between the inner and outer regions, which agrees with a specific stellar population difference (e.g., higher EHB populations), and the ∼0.5-2 Gyr age difference suggests multi-stage formation. Our results are best explained by inside-out formation: rapid star formation within the core at early epochs (>4 Gyr ago

  13. UV-BRIGHT NEARBY EARLY-TYPE GALAXIES OBSERVED IN THE MID-INFRARED: EVIDENCE FOR A MULTI-STAGE FORMATION HISTORY BY WAY OF WISE AND GALEX IMAGING

    Petty, S. M.; Farrah, D. G. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Neill, J. D.; Bridge, C. R. [Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Jarrett, T. H.; Tsai, C.-W. [Astronomy Department, University of Cape Town, Rondebosch 7701 (South Africa); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Rich, R. M.; Lake, S. E.; Wright, E. L. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Benford, D. J. [NASA, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Masci, F. J. [IPAC, California Institute of Technology, Pasadena, CA 91125 (United States)

    2013-10-01

    In the local universe, 10% of massive elliptical galaxies are observed to exhibit a peculiar property: a substantial excess of ultraviolet emission than what is expected from their old, red stellar populations. Several origins for this ultraviolet excess (UVX) have been proposed including a population of hot young stars and a population of old, blue horizontal branch or extended horizontal branch (BHB or EHB) stars that have undergone substantial mass loss from their outer atmospheres. We explore the radial distribution of UVX in a selection of 49 nearby E/S0-type galaxies by measuring their extended photometry in the UV through mid-infrared (mid-IR) with the Galaxy Evolution Explorer (GALEX), the Sloan Digital Sky Survey, and the Wide-field Infrared Survey Explorer (WISE). We compare UV/optical and UV/mid-IR colors with the Flexible Stellar Population Synthesis models, which allow for the inclusion of EHB stars. We find that combined WISE mid-IR and GALEX UV colors are more effective in distinguishing models than optical colors, and that the UV/mid-IR combination is sensitive to the EHB fraction. There are strong color gradients, with the outer radii bluer than the inner half-light radii by {approx}1 mag. This color difference is easily accounted for with an increase in the BHB fraction of 0.25 with radius. We estimated that the average ages for the inner and outer radii are 7.0 {+-} 0.3 Gyr, and 6.2 {+-} 0.2 Gyr, respectively, with the implication that the outer regions are likely to have formed {approx}1 Gyr after the inner regions. Additionally, we find that metallicity gradients are likely not a significant factor in the color difference. The separation of color between the inner and outer regions, which agrees with a specific stellar population difference (e.g., higher EHB populations), and the {approx}0.5-2 Gyr age difference suggests multi-stage formation. Our results are best explained by inside-out formation: rapid star formation within the core at early

  14. DEEP GALEX OBSERVATIONS OF THE COMA CLUSTER: SOURCE CATALOG AND GALAXY COUNTS

    Hammer, D.; Hornschemeier, A. E.; Miller, N.; Jenkins, L.; Mobasher, B.; Smith, R.; Arnouts, S.; Milliard, B.

    2010-01-01

    We present a source catalog from a deep 26 ks Galaxy Evolution Explorer (GALEX) observation of the Coma cluster in the far-UV (FUV; 1530 A) and near-UV (NUV; 2310 A) wavebands. The observed field is centered ∼0. 0 9 (1.6 Mpc) southwest of the Coma core in a well-studied region of the cluster known as 'Coma-3'. The entire field is located within the apparent virial radius of the Coma cluster, and has optical photometric coverage with Sloan Digital Sky Survey (SDSS) and deep spectroscopic coverage to r ∼ 21. We detect GALEX sources to NUV = 24.5 and FUV = 25.0, which corresponds to a star formation rate of ∼10 -3 M sun yr -1 for galaxies at the distance of Coma. We have assembled a catalog of 9700 galaxies with GALEX and SDSS photometry, including 242 spectroscopically confirmed Coma member galaxies that span a large range of galaxy types from giant spirals and elliptical galaxies to dwarf irregular and early-type galaxies. The full multi-wavelength catalog (cluster plus background galaxies) is ∼80% complete to NUV = 23 and FUV = 23.5. The GALEX images presented here are very deep and include detections of many resolved cluster members superposed on a dense field of unresolved background galaxies. This required a two-fold approach to generating a source catalog: we used a Bayesian deblending algorithm to measure faint and compact sources (using SDSS coordinates as position prior), and used the GALEX pipeline catalog for bright and/or extended objects. We performed simulations to assess the importance of systematic effects (e.g., object blends, source confusion, Eddington Bias) that influence the source detection and photometry when using both methods. The Bayesian deblending method roughly doubles the number of source detections and provides reliable photometry to a few magnitudes deeper than the GALEX pipeline catalog. This method is free from source confusion over the UV magnitude range studied here; we estimate that the GALEX pipeline catalogs are

  15. Joint XMM-Newton and Chandra observations of the NGC 1407/1400 complex: A tail of an early-type galaxy and a tale of a nearby merging group

    Su, Yuanyuan [Department of Physics and Astronomy, University of California at Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States); Gu, Liyi [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan); White III, Raymond E.; Irwin, Jimmy, E-mail: yuanyuas@uci.edu [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States)

    2014-05-10

    The nearby group centered on its bright central galaxy NGC 1407 has been suggested by previous kinematic studies to be an unusually dark system. It is also known for hosting a bright galaxy, NGC 1400, with a large radial velocity (1200 km s{sup –1}) with respect to the group center. Previous ROSAT X-ray observations revealed an extended region of enhanced surface brightness just eastward of NGC 1400. We investigate the NGC 1407/1400 complex with XMM-Newton and Chandra observations. We find that the temperature and metallicity of the enhanced region are different (cooler and more metal rich) than those of the surrounding group gas but are consistent with those of the interstellar medium (ISM) in NGC 1400. The relative velocity of NGC 1400 is large enough that much of its ISM could have been ram pressure stripped while plunging through the group atmosphere. We conclude that the enhanced region is likely to be hot gas stripped from the ISM of NGC 1400. We constrain the motion of NGC 1400 using the pressure jump at its associated stagnation front and the total mass profile of the NGC 1407 group. We conclude that NGC 1400 is moving within ∼30° of the line of sight with Mach number M≲3. We do not detect any obvious shock features in this complex, perhaps because of the high line-of-sight motion of NGC 1400. With an XMM-Newton pointing on the relatively relaxed eastern side of NGC 1407, we derive a hydrostatic mass for this group of ∼1 × 10{sup 13} M {sub ☉} within 100 kpc. The total mass extrapolated to the virial radius (681 kpc) is 3.8 × 10{sup 13} M {sub ☉}, which puts an upper limit of ∼300 M{sub ⊙}/L{sub B{sub ⊙}} on the mass-to-light ratio of this group. This suggests that the NGC 1407 group is not an unusually dark group.

  16. Quasar feedback in the early Universe : The case of SDSS J1148+5251

    Valiante, Rosa; Schneider, Raffaella; Maiolino, Roberto; Salvadori, Stefania; Bianchi, Simone

    2012-01-01

    Galaxy-scale gas outflows triggered by active galactic nuclei have been proposed as a key physical process to regulate the co-evolution of nuclear black holes and their host galaxies. The recent detection of a massive gas outflow in one of the most distant quasars, SDSS J1148+5251 at z = 6.4,

  17. Quasar feedback in the early Universe: the case of SDSS J1148+5251

    Valiante, Rosa; Schneider, Raffaella; Maiolino, Roberto; Salvadori, Stefania; Bianchi, Simone

    2012-01-01

    Galaxy-scale gas outflows triggered by active galactic nuclei have been proposed as a key physical process to regulate the co-evolution of nuclear black holes and their host galaxies. The recent detection of a massive gas outflow in one of the most distant quasars, SDSS J1148+5251 at z= 6.4,

  18. Effects of the environment on galaxies in the Catalogue of Isolated Galaxies: physical satellites and large scale structure

    Argudo-Fernández, M.; Verley, S.; Bergond, G.; Sulentic, J.; Sabater, J.; Fernández Lorenzo, M.; Espada, D.; Leon, S.; Sánchez-Expósito, S.; Santander-Vela, J. D.; Verdes-Montenegro, L.

    2014-04-01

    Context. We present a study of the 3D environment for a sample of 386 galaxies in the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973) using the Ninth Data Release of the Sloan Digital Sky Survey (SDSS-DR9). Aims: We aim to identify and quantify the effects of the satellite distribution around a sample of galaxies in the CIG, as well as the effects of the large-scale structure (LSS). Methods: To recover the physically bound galaxies we first focused on the satellites that are within the escape speed of each CIG galaxy. We also propose a more conservative method using the stacked Gaussian distribution of the velocity difference of the neighbours. The tidal strengths affecting the primary galaxy were estimated to quantify the effects of the local and LSS environments. We also defined the projected number density parameter at the fifth nearest neighbour to characterise the LSS around the CIG galaxies. Results: Out of the 386 CIG galaxies considered in this study, at least 340 (88% of the sample) have no physically linked satellite. Following the more conservative Gaussian distribution of physical satellites around the CIG galaxies leads to upper limits. Out of the 386 CIG galaxies, 327 (85% of the sample) have no physical companion within a projected distance of 0.3 Mpc. The CIG galaxies are distributed following the LSS of the local Universe, although presenting a large heterogeneity in their degree of connection with it. When present around a CIG galaxy, the effect of physically bound galaxies largely dominates (typically by more than 90%) the tidal strengths generated by the LSS. Conclusions: The CIG samples a variety of environments, from galaxies with physical satellites to galaxies without neighbours within 3 Mpc. A clear segregation appears between early-type CIG galaxies with companions and isolated late-type CIG galaxies. Isolated galaxies are in general bluer, with probably younger stellar populations and very high star formation compared with older

  19. After SDSS-IV: Pioneering Panoptic Spectroscopy

    Kollmeier, Juna; AS4 Collaboration

    2018-01-01

    I will describe the current plans for a next generation sky survey that will begin After SDSS-IV --- AS4. AS4 will be an unprecedented all-sky spectroscopic survey of over six million objects. It is designed to decode the history of the Milky Way galaxy, trace the emergence of the chemical elements, reveal the inner workings of stars, the growth of black holes, and investigate the origin of planets. It will provide the most comprehensive all-sky spectroscopy to multiply the science from the Gaia, TESS and eROSITA missions. AS4 will also create a contiguous spectroscopic map of the interstellar gas in the Milky Way and nearby galaxies that is 1,000 times larger than the state of the art, uncovering the self-regulation mechanisms of Galactic ecosystems. It will pioneer systematic, spectroscopic monitoring across the whole sky, revealing changes on timescales from 20 minutes to 20 years. The project is now developing new hardware to build on the SDSS-IV infrastructure, designing the detailed survey strategy, and actively seeking to complete its consortium of institutional and individual members.

  20. The different star formation histories of blue and red spiral and elliptical galaxies

    Tojeiro, Rita; Masters, Karen L.; Richards, Joshua; Percival, Will J.; Bamford, Steven P.; Maraston, Claudia; Nichol, Robert C.; Skibba, Ramin; Thomas, Daniel

    2013-06-01

    We study the spectral properties of intermediate mass galaxies (M* ˜ 1010.7 M⊙) as a function of colour and morphology. We use Galaxy Zoo to define three morphological classes of galaxies, namely early types (ellipticals), late-type (disc-dominated) face-on spirals and early-type (bulge-dominated) face-on spirals. We classify these galaxies as blue or red according to their Sloan Digital Sky Survey (SDSS) g - r colour and use the spectral fitting code Versatile Spectral Analyses to calculate time-resolved star formation histories, metallicity and total starlight dust extinction from their SDSS fibre spectra. We find that red late-type spirals show less star formation in the last 500 Myr than blue late-type spirals by up to a factor of 3, but share similar star formation histories at earlier times. This decline in recent star formation explains their redder colour: their chemical and dust content are the same. We postulate that red late-type spirals are recent descendants of blue late-type spirals, with their star formation curtailed in the last 500 Myr. The red late-type spirals are however still forming stars ≃17 times faster than red ellipticals over the same period. Red early-type spirals lie between red late-type spirals and red ellipticals in terms of recent-to-intermediate star formation and dust content. Therefore, it is plausible that these galaxies represent an evolutionary link between these two populations. They are more likely to evolve directly into red ellipticals than red late-type spirals, which show star formation histories and dust content closer to blue late-type spirals. Blue ellipticals show similar star formation histories as blue spirals (regardless of type), except that they have formed less stars in the last 100 Myr. However, blue ellipticals have different dust content, which peaks at lower extinction values than all spiral galaxies. Therefore, many blue ellipticals are unlikely to be descendants of blue spirals, suggesting there may

  1. Deep Galex Observations of the Coma Cluster: Source Catalog and Galaxy Counts

    Hammer, D.; Hornschemeier, A. E.; Mobasher, B.; Miller, N.; Smith, R.; Arnouts, S.; Milliard, B.; Jenkins, L.

    2010-01-01

    We present a source catalog from deep 26 ks GALEX observations of the Coma cluster in the far-UV (FUV; 1530 Angstroms) and near-UV (NUV; 2310 Angstroms) wavebands. The observed field is centered 0.9 deg. (1.6 Mpc) south-west of the Coma core, and has full optical photometric coverage by SDSS and spectroscopic coverage to r-21. The catalog consists of 9700 galaxies with GALEX and SDSS photometry, including 242 spectroscopically-confirmed Coma member galaxies that range from giant spirals and elliptical galaxies to dwarf irregular and early-type galaxies. The full multi-wavelength catalog (cluster plus background galaxies) is 80% complete to NUV=23 and FUV=23.5, and has a limiting depth at NUV=24.5 and FUV=25.0 which corresponds to a star formation rate of 10(exp -3) solar mass yr(sup -1) at the distance of Coma. The GALEX images presented here are very deep and include detections of many resolved cluster members superposed on a dense field of unresolved background galaxies. This required a two-fold approach to generating a source catalog: we used a Bayesian deblending algorithm to measure faint and compact sources (using SDSS coordinates as a position prior), and used the GALEX pipeline catalog for bright and/or extended objects. We performed simulations to assess the importance of systematic effects (e.g. object blends, source confusion, Eddington Bias) that influence source detection and photometry when using both methods. The Bayesian deblending method roughly doubles the number of source detections and provides reliable photometry to a few magnitudes deeper than the GALEX pipeline catalog. This method is also free from source confusion over the UV magnitude range studied here: conversely, we estimate that the GALEX pipeline catalogs are confusion limited at NUV approximately 23 and FUV approximately 24. We have measured the total UV galaxy counts using our catalog and report a 50% excess of counts across FUV=22-23.5 and NUV=21.5-23 relative to previous GALEX

  2. A multiwavelength survey of H I-excess galaxies with surprisingly inefficient star formation

    Geréb, K.; Janowiecki, S.; Catinella, B.; Cortese, L.; Kilborn, V.

    2018-05-01

    We present the results of a multiwavelength survey of H I-excess galaxies, an intriguing population with large H I reservoirs associated with little current star formation. These galaxies have stellar masses M⋆ > 1010 M⊙, and were identified as outliers in the gas fraction versus NUV-r colour and stellar mass surface density scaling relations based on the GALEX Arecibo SDSS Survey (GASS). We obtained H I interferometry with the Giant Metrewave Radio Telescope, Keck optical long-slit spectroscopy, and deep optical imaging (where available) for four galaxies. Our analysis reveals multiple possible reasons for the H I excess in these systems. One galaxy, AGC 10111, shows an H I disc that is counter-rotating with respect to the stellar bulge, a clear indication of external origin of the gas. Another galaxy appears to host a Malin 1-type disc, where a large specific angular momentum has to be invoked to explain the extreme M_{H I}/M⋆ ratio of 166 per cent. The other two galaxies have early-type morphology with very high gas fractions. The lack of merger signatures (unsettled gas, stellar shells, and streams) in these systems suggests that these gas-rich discs have been built several Gyr ago, but it remains unclear how the gas reservoirs were assembled. Numerical simulations of large cosmological volumes are needed to gain insight into the formation of these rare and interesting systems.

  3. The SAURON project - XI. Stellar populations from absorption-line strength maps of 24 early-type spirals

    Peletier, Reynier F.; Falcon-Barroso, Jesus; Bacon, Roland; Cappellari, Michele; Davies, Roger L.; de Zeeuw, P. T.; Emsellem, Eric; Ganda, Katia; Krajnovic, Davor; Kuntschner, Harald; McDermid, Richard M.; Sarzi, Marc; van de Ven, Glenn

    2007-01-01

    We present absorption-line strength maps of a sample of 24 representative early-type spiral galaxies, mostly of type Sa, obtained as part of the SAURON (Spectrographic Areal Unit for Research on Optical Nebulae) survey of nearby galaxies using our custom-built integral-field spectrograph. Using

  4. The optical, infrared and radio properties of extragalactic sources observed by SDSS, 2mass and first surveys

    Z. Ivezic et al.

    2002-01-01

    We positionally match sources observed by the Sloan Digital Sky Survey (SDSS), the Two Micron All Sky Survey (2MASS), and the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey. Practically all 2MASS sources are matched to an SDSS source within 2 arcsec; ∼ 11% of them are optically resolved galaxies and the rest are dominated by stars. About 1/3 of FIRST sources are matched to an SDSS source within 2 arcsec; ∼ 80% of these are galaxies and the rest are dominated by quasars. Based on these results, we project that by the completion of these surveys the matched samples will include about 10 7 and 10 6 galaxies observed by both SDSS and 2MASS, and about 250,000 galaxies and 50,000 quasars observed by both SDSS and FIRST. Here we present a preliminary analysis of the optical, infrared and radio properties for the extragalactic sources from the matched samples. In particular, we find that the fraction of quasars with stellar colors missed by the SDSS spectroscopic survey is probably not larger than ∼ 10%, and that the optical colors of radio-loud quasars are ∼ 0.05 mag. redder (with 4σ significance) than the colors of radio-quiet quasars

  5. Creating lenticular galaxies with mergers

    Querejeta, Miguel; Eliche-Moral, M. Carmen; Tapia, Trinidad; Borlaff, Alejandro; van de Ven, Glenn; Lyubenova, Mariya; Martig, Marie; Falcón-Barroso, Jesús; Méndez-Abreu, Jairo; Zamorano, Jaime; Gallego, Jesús

    Lenticular galaxies (S0s) represent the majority of early-type galaxies in the local Universe, but their formation channels are still poorly understood. While galaxy mergers are obvious pathways to suppress star formation and increase bulge sizes, the marked parallelism between spiral and lenticular

  6. QUENCHING DEPENDS ON MORPHOLOGIES: IMPLICATIONS FROM THE ULTRAVIOLET-OPTICAL RADIAL COLOR DISTRIBUTIONS IN GREEN VALLEY GALAXIES

    Pan, Zhizheng; Lin, Weipeng [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Science, 80 Nandan Road, Shanghai 200030 (China); Li, Jinrong; Kong, Xu [Center of Astrophysics, University of Science and Technology of China, Jinzhai Road 96, Hefei 230026 (China); Wang, Jing, E-mail: panzz@shao.ac.cn, E-mail: linwp@shao.ac.cn [CSIRO Astronomy and Space Science, Australia Telescope National Facility, PO Box 76, Epping, NSW 1710 (Australia)

    2014-09-01

    In this Letter, we analyze the radial ultraviolet-optical color distributions in a sample of low redshift green valley galaxies, with the Galaxy Evolution Explorer (GALEX)+Sloan Digital Sky Survey (SDSS) images, to investigate how the residual recent star formation is distributed in these galaxies. We find that the dust-corrected u – r colors of early-type galaxies (ETGs) are flat out to R {sub 90}, while the colors monotonously turn blue when r > 0.5 R {sub 50} for late-type galaxies (LTGs). More than half of the ETGs are blue-cored and have remarkable positive NUV – r color gradients, suggesting that their star formations are centrally concentrated. The rest have flat color distributions out to R {sub 90}. The centrally concentrated star formation activity in a large portion of ETGs is confirmed by the SDSS spectroscopy, showing that ∼50% of the ETGs have EW(Hα) >6.0 Å. Of the LTGs, 95% show uniform radial color profiles, which can be interpreted as a red bulge plus an extended blue disk. The links between the two kinds of ETGs, e.g., those objects having remarkable ''blue-cores'' and those having flat color gradients, are less known and require future investigations. It is suggested that the LTGs follow a general model by which quenching first occurs in the core regions, and then finally extend to the rest of the galaxy. Our results can be re-examined and have important implications for the IFU surveys, such as MaNGA and SAMI.

  7. QUENCHING DEPENDS ON MORPHOLOGIES: IMPLICATIONS FROM THE ULTRAVIOLET-OPTICAL RADIAL COLOR DISTRIBUTIONS IN GREEN VALLEY GALAXIES

    Pan, Zhizheng; Lin, Weipeng; Li, Jinrong; Kong, Xu; Wang, Jing

    2014-01-01

    In this Letter, we analyze the radial ultraviolet-optical color distributions in a sample of low redshift green valley galaxies, with the Galaxy Evolution Explorer (GALEX)+Sloan Digital Sky Survey (SDSS) images, to investigate how the residual recent star formation is distributed in these galaxies. We find that the dust-corrected u – r colors of early-type galaxies (ETGs) are flat out to R 90 , while the colors monotonously turn blue when r > 0.5 R 50 for late-type galaxies (LTGs). More than half of the ETGs are blue-cored and have remarkable positive NUV – r color gradients, suggesting that their star formations are centrally concentrated. The rest have flat color distributions out to R 90 . The centrally concentrated star formation activity in a large portion of ETGs is confirmed by the SDSS spectroscopy, showing that ∼50% of the ETGs have EW(Hα) >6.0 Å. Of the LTGs, 95% show uniform radial color profiles, which can be interpreted as a red bulge plus an extended blue disk. The links between the two kinds of ETGs, e.g., those objects having remarkable ''blue-cores'' and those having flat color gradients, are less known and require future investigations. It is suggested that the LTGs follow a general model by which quenching first occurs in the core regions, and then finally extend to the rest of the galaxy. Our results can be re-examined and have important implications for the IFU surveys, such as MaNGA and SAMI

  8. BVRI SURFACE PHOTOMETRY OF ISOLATED GALAXY TRIPLETS

    Hernandez-Toledo, H. M.; Mendez-Hernandez, H.; Aceves, H.; OlguIn, L.

    2011-01-01

    Optical broadband BVRI observations of 54 galaxies selected from the Catalog of Isolated Triplets of Galaxies in the Northern Hemisphere have been carried out at San Pedro Martir National Observatory to evaluate their photometric and morphological properties. We complement our analysis with Two-Micron All Sky Survey (2MASS) and Sloan Digital Sky Survey (SDSS) images and look for signatures likely related to interactions/mergers. We report apparent/absolute BVRI magnitudes and colors for the 54 galaxies. The membership of these galaxies is re-evaluated by imposing a reasonable condition of concordant redshifts upon the original selection criteria, rendering a final sample of 34 galaxies in 13 triplets, 12 galaxies in close pairs, and 8 galaxy outliers. The triplets are spiral-dominated systems in different dynamical stages from loosely interacting to almost merged objects. The incidence fraction of features likely associated with interactions is ∼56%, similar to those found in northern and southern compact groups. The average fraction of bars is 35% with a mean value of maximum bar ellipticity ε max ∼ 0.4. Bars are hosted in the late-type triplet spirals, almost twice more than in early-type spirals. The global fraction of rings is 20%, all in the late-type components. The overdensity of triplets with respect to the background and their current dynamical status, as devised from our estimate of their dynamical parameters, namely the harmonic radius R H , velocity dispersion σ, dimensionless crossing time H 0 τ c , and virial mass M V , appear to be sufficient to favor galaxy transformations similar to those seen in dense groups and clusters. By contrast, the lower fraction of bonafide ellipticals and the relatively higher fraction of late-type spirals make these triplets essentially different from the Hickson Compact Groups and more representative of the field. A modest 1.6 enhancement factor in the optical luminosity of the late-type triplet components

  9. SDSS-III: MASSIVE SPECTROSCOPIC SURVEYS OF THE DISTANT UNIVERSE, THE MILKY WAY, AND EXTRA-SOLAR PLANETARY SYSTEMS

    Eisenstein, Daniel J.; Weinberg, David H.; Agol, Eric; Anderson, Scott F.; Aihara, Hiroaki; Allende Prieto, Carlos; Arns, James A.; Aubourg, Eric; Bailey, Stephen; Balbinot, Eduardo; Barkhouser, Robert; Beers, Timothy C.; Berlind, Andreas A.; Bickerton, Steven J.; Bizyaev, Dmitry; Blanton, Michael R.; Bochanski, John J.; Bolton, Adam S.

    2011-01-01

    Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of the Milky Way, and the population of giant planets around other stars. In keeping with SDSS tradition, SDSS-III will provide regular public releases of all its data, beginning with SDSS Data Release 8 (DR8), which was made public in 2011 January and includes SDSS-I and SDSS-II images and spectra reprocessed with the latest pipelines and calibrations produced for the SDSS-III investigations. This paper presents an overview of the four surveys that comprise SDSS-III. The Baryon Oscillation Spectroscopic Survey will measure redshifts of 1.5 million massive galaxies and Lyα forest spectra of 150,000 quasars, using the baryon acoustic oscillation feature of large-scale structure to obtain percent-level determinations of the distance scale and Hubble expansion rate at z 5 evolved, late-type stars, measuring separate abundances for ∼15 elements per star and creating the first high-precision spectroscopic survey of all Galactic stellar populations (bulge, bar, disks, halo) with a uniform set of stellar tracers and spectral diagnostics. The Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS) will monitor radial velocities of more than 8000 FGK stars with the sensitivity and cadence (10-40 m s -1 , ∼24 visits per star) needed to detect giant planets with periods up to two years, providing an unprecedented data set for understanding the formation and dynamical evolution of giant planet systems. As of 2011 January, SDSS-III has obtained spectra of more than 240,000 galaxies, 29,000 z ≥ 2.2 quasars, and 140,000 stars, including 74,000 velocity measurements of 2580 stars for MARVELS.

  10. SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way, and Extra-Solar Planetary Systems

    Eisenstein, Daniel J.; Weinberg, David H.; Agol, Eric; Aihara, Hiroaki; Allende Prieto, Carlos; Anderson, Scott F.; Arns, James A.; Aubourg, Éric; Bailey, Stephen; Balbinot, Eduardo; Barkhouser, Robert; Beers, Timothy C.; Berlind, Andreas A.; Bickerton, Steven J.; Bizyaev, Dmitry; Blanton, Michael R.; Bochanski, John J.; Bolton, Adam S.; Bosman, Casey T.; Bovy, Jo; Brandt, W. N.; Breslauer, Ben; Brewington, Howard J.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Burger, Dan; Busca, Nicolas G.; Campbell, Heather; Cargile, Phillip A.; Carithers, William C.; Carlberg, Joleen K.; Carr, Michael A.; Chang, Liang; Chen, Yanmei; Chiappini, Cristina; Comparat, Johan; Connolly, Natalia; Cortes, Marina; Croft, Rupert A. C.; Cunha, Katia; da Costa, Luiz N.; Davenport, James R. A.; Dawson, Kyle; De Lee, Nathan; Porto de Mello, Gustavo F.; de Simoni, Fernando; Dean, Janice; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eiting, Jacob M.; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Femenía Castellá, Bruno; Dutra Ferreira, Leticia; Fitzgerald, Greg; Fleming, Scott W.; Font-Ribera, Andreu; Ford, Eric B.; Frinchaboy, Peter M.; García Pérez, Ana Elia; Gaudi, B. Scott; Ge, Jian; Ghezzi, Luan; Gillespie, Bruce A.; Gilmore, G.; Girardi, Léo; Gott, J. Richard; Gould, Andrew; Grebel, Eva K.; Gunn, James E.; Hamilton, Jean-Christophe; Harding, Paul; Harris, David W.; Hawley, Suzanne L.; Hearty, Frederick R.; Hennawi, Joseph F.; González Hernández, Jonay I.; Ho, Shirley; Hogg, David W.; Holtzman, Jon A.; Honscheid, Klaus; Inada, Naohisa; Ivans, Inese I.; Jiang, Linhua; Jiang, Peng; Johnson, Jennifer A.; Jordan, Cathy; Jordan, Wendell P.; Kauffmann, Guinevere; Kazin, Eyal; Kirkby, David; Klaene, Mark A.; Knapp, G. R.; Kneib, Jean-Paul; Kochanek, C. S.; Koesterke, Lars; Kollmeier, Juna A.; Kron, Richard G.; Lampeitl, Hubert; Lang, Dustin; Lawler, James E.; Le Goff, Jean-Marc; Lee, Brian L.; Lee, Young Sun; Leisenring, Jarron M.; Lin, Yen-Ting; Liu, Jian; Long, Daniel C.; Loomis, Craig P.; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; Ma, Bo; Ma, Zhibo; MacDonald, Nicholas; Mack, Claude; Mahadevan, Suvrath; Maia, Marcio A. G.; Majewski, Steven R.; Makler, Martin; Malanushenko, Elena; Malanushenko, Viktor; Mandelbaum, Rachel; Maraston, Claudia; Margala, Daniel; Maseman, Paul; Masters, Karen L.; McBride, Cameron K.; McDonald, Patrick; McGreer, Ian D.; McMahon, Richard G.; Mena Requejo, Olga; Ménard, Brice; Miralda-Escudé, Jordi; Morrison, Heather L.; Mullally, Fergal; Muna, Demitri; Murayama, Hitoshi; Myers, Adam D.; Naugle, Tracy; Neto, Angelo Fausti; Nguyen, Duy Cuong; Nichol, Robert C.; Nidever, David L.; O'Connell, Robert W.; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Daniel J.; Padmanabhan, Nikhil; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, Kaike; Pandey, Parul; Parejko, John K.; Pâris, Isabelle; Pellegrini, Paulo; Pepper, Joshua; Percival, Will J.; Petitjean, Patrick; Pfaffenberger, Robert; Pforr, Janine; Phleps, Stefanie; Pichon, Christophe; Pieri, Matthew M.; Prada, Francisco; Price-Whelan, Adrian M.; Raddick, M. Jordan; Ramos, Beatriz H. F.; Reid, I. Neill; Reyle, Celine; Rich, James; Richards, Gordon T.; Rieke, George H.; Rieke, Marcia J.; Rix, Hans-Walter; Robin, Annie C.; Rocha-Pinto, Helio J.; Rockosi, Constance M.; Roe, Natalie A.; Rollinde, Emmanuel; Ross, Ashley J.; Ross, Nicholas P.; Rossetto, Bruno; Sánchez, Ariel G.; Santiago, Basilio; Sayres, Conor; Schiavon, Ricardo; Schlegel, David J.; Schlesinger, Katharine J.; Schmidt, Sarah J.; Schneider, Donald P.; Sellgren, Kris; Shelden, Alaina; Sheldon, Erin; Shetrone, Matthew; Shu, Yiping; Silverman, John D.; Simmerer, Jennifer; Simmons, Audrey E.; Sivarani, Thirupathi; Skrutskie, M. F.; Slosar, Anže; Smee, Stephen; Smith, Verne V.; Snedden, Stephanie A.; Stassun, Keivan G.; Steele, Oliver; Steinmetz, Matthias; Stockett, Mark H.; Stollberg, Todd; Strauss, Michael A.; Szalay, Alexander S.; Tanaka, Masayuki; Thakar, Aniruddha R.; Thomas, Daniel; Tinker, Jeremy L.; Tofflemire, Benjamin M.; Tojeiro, Rita; Tremonti, Christy A.; Vargas Magaña, Mariana; Verde, Licia; Vogt, Nicole P.; Wake, David A.; Wan, Xiaoke; Wang, Ji; Weaver, Benjamin A.; White, Martin; White, Simon D. M.; Wilson, John C.; Wisniewski, John P.; Wood-Vasey, W. Michael; Yanny, Brian; Yasuda, Naoki; Yèche, Christophe; York, Donald G.; Young, Erick; Zasowski, Gail; Zehavi, Idit; Zhao, Bo

    2011-09-01

    Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of the Milky Way, and the population of giant planets around other stars. In keeping with SDSS tradition, SDSS-III will provide regular public releases of all its data, beginning with SDSS Data Release 8 (DR8), which was made public in 2011 January and includes SDSS-I and SDSS-II images and spectra reprocessed with the latest pipelines and calibrations produced for the SDSS-III investigations. This paper presents an overview of the four surveys that comprise SDSS-III. The Baryon Oscillation Spectroscopic Survey will measure redshifts of 1.5 million massive galaxies and Lyα forest spectra of 150,000 quasars, using the baryon acoustic oscillation feature of large-scale structure to obtain percent-level determinations of the distance scale and Hubble expansion rate at z R = λ/Δλ ≈ 1800) optical spectra of 118,000 stars in a variety of target categories, probing chemical evolution, stellar kinematics and substructure, and the mass profile of the dark matter halo from the solar neighborhood to distances of 100 kpc. APOGEE, the Apache Point Observatory Galactic Evolution Experiment, will obtain high-resolution (R ≈ 30,000), high signal-to-noise ratio (S/N >= 100 per resolution element), H-band (1.51 μm data set for understanding the formation and dynamical evolution of giant planet systems. As of 2011 January, SDSS-III has obtained spectra of more than 240,000 galaxies, 29,000 z >= 2.2 quasars, and 140,000 stars, including 74,000 velocity measurements of 2580 stars for MARVELS.

  11. Golden gravitational lensing systems from the Sloan Lens ACS Survey - II. SDSS J1430+4105: a precise inner total mass profile from lensing alone

    Eichner, Thomas; Seitz, Stella; Bauer, Anne

    2012-12-01

    We study the Sloan Lens ACS (SLACS) survey strong-lensing system SDSS J1430+4105 at zl = 0.285. The lensed source (zs = 0.575) of this system has a complex morphology with several subcomponents. Its subcomponents span a radial range from 4 to 10 kpc in the plane of the lens. Therefore, we can constrain the slope of the total projected mass profile around the Einstein radius from lensing alone. We measure a density profile that is slightly but not significantly shallower than isothermal at the Einstein radius. We decompose the mass of the lensing galaxy into a de Vaucouleurs component to trace the stars and an additional dark component. The spread of multiple-image components over a large radial range also allows us to determine the amplitude of the de Vaucouleurs and dark matter components separately. We get a mass-to-light ratio of M de Vauc LB ≈ (5.5±1.5) M⊙L⊙,B and a dark matter fraction within the Einstein radius of ≈20 to 40 per cent. Modelling the star formation history assuming composite stellar populations at solar metallicity to the galaxy's photometry yields a mass-to-light ratio of M, salp LB ≈ 4.0-1.3+0.6 M⊙L⊙,B and M, chab LB ≈ 2.3-0.8+0.3 M⊙L⊙,B for Salpeter and Chabrier initial mass functions, respectively. Hence, the mass-to-light ratio derived from lensing is more Salpeter like, in agreement with results for massive Coma galaxies and other nearby massive early-type galaxies. We examine the consequences of the galaxy group in which the lensing galaxy is embedded, showing that it has little influence on the mass-to-light ratio obtained for the de Vaucouleurs component of the lensing galaxy. Finally, we decompose the projected, azimuthally averaged 2D density distribution of the de Vaucouleurs and dark matter components of the lensing signal into spherically averaged 3D density profiles. We can show that the 3D dark and luminous matter density within the Einstein radius (REin ≈ 0.6 Reff) of this SLACS galaxy is similar to the

  12. Early-type semidetached system LY Aurigae

    Li, Y.F.; Leung, K.C.

    1985-01-01

    In an effort to resolve a controversy regarding the configuration, mass ratio, and evolutionary status of the early-type close binary system LY Aur, the six bandpass OAO 2 observations of Heap and the ground-based observations combined by Eaton were analyzed. The Wilson and Devinney approach was used. The system is found to be semidetached, with the cooler and less massive component filling its Roche lobe, while the hotter component is close to its Roche surface. The system is not an early-type zero-age contact, as was suspected earlier. 20 references

  13. Detecting active comets with SDSS

    Solontoi, Michael; Ivezic, Zeljko; /Washington U., Seattle, Astron. Dept.; West, Andrew A.; /MIT, MKI; Claire, Mark; /Washington U., Seattle, Astron. Dept.; Juric, Mario; /Princeton U. Observ.; Becker, Andrew; Jones, Lynne; /Washington U., Seattle, Astron. Dept.; Hall, Patrick B.; /York U., Canada; Kent, Steve; /Fermilab; Lupton, Robert H.; /Princeton U. Observ.; Quinn, Tom; /Washington U., Seattle, Astron. Dept. /Princeton U. Observ.

    2010-12-01

    Using a sample of serendipitously discovered active comets in the Sloan Digital Sky Survey (SDSS), we develop well-controlled selection criteria for greatly increasing the efficiency of comet identification in the SDSS catalogs. After follow-up visual inspection of images to reject remaining false positives, the total sample of SDSS comets presented here contains 19 objects, roughly one comet per 10 million other SDSS objects. The good understanding of selection effects allows a study of the population statistics, and we estimate the apparent magnitude distribution to r {approx} 18, the ecliptic latitude distribution, and the comet distribution in SDSS color space. The most surprising results are the extremely narrow range of colors for comets in our sample (e.g. root-mean-square scatter of only {approx}0.06 mag for the g-r color), and the similarity of comet colors to those of jovian Trojans. We discuss the relevance of our results for upcoming deep multi-epoch optical surveys such as the Dark Energy Survey, Pan-STARRS, and the Large Synoptic Survey Telescope (LSST), and estimate that LSST may produce a sample of about 10,000 comets over its 10-year lifetime.

  14. VizieR Online Data Catalog: Inner/outer HII regions: galaxy sample (Rodriguez-Baras+, 2018)

    Rodriguez-Baras, M.; Diaz, A. I.; Rosales-Ortega, F. F.; Sanchez, S. F.

    2017-11-01

    Physical properties for 263 isolated spiral galaxies, observed by the CALIFA survey, are presented. These galaxies compose this work galaxy sample. For each galaxy redshift, morphological type, inclination, distance, effective radius, g and r SDSS magnitudes, absolute B magnitude and total number of HII regions extracted in the galaxy are given. (1 data file).

  15. THE SWIFT AGN AND CLUSTER SURVEY. II. CLUSTER CONFIRMATION WITH SDSS DATA

    Griffin, Rhiannon D.; Dai, Xinyu; Kochanek, Christopher S.; Bregman, Joel N.

    2016-01-01

    We study 203 (of 442) Swift AGN and Cluster Survey extended X-ray sources located in the SDSS DR8 footprint to search for galaxy over-densities in three-dimensional space using SDSS galaxy photometric redshifts and positions near the Swift cluster candidates. We find 104 Swift clusters with a >3σ galaxy over-density. The remaining targets are potentially located at higher redshifts and require deeper optical follow-up observations for confirmation as galaxy clusters. We present a series of cluster properties including the redshift, brightest cluster galaxy (BCG) magnitude, BCG-to-X-ray center offset, optical richness, and X-ray luminosity. We also detect red sequences in ∼85% of the 104 confirmed clusters. The X-ray luminosity and optical richness for the SDSS confirmed Swift clusters are correlated and follow previously established relations. The distribution of the separations between the X-ray centroids and the most likely BCG is also consistent with expectation. We compare the observed redshift distribution of the sample with a theoretical model, and find that our sample is complete for z ≲ 0.3 and is still 80% complete up to z ≃ 0.4, consistent with the SDSS survey depth. These analysis results suggest that our Swift cluster selection algorithm has yielded a statistically well-defined cluster sample for further study of cluster evolution and cosmology. We also match our SDSS confirmed Swift clusters to existing cluster catalogs, and find 42, 23, and 1 matches in optical, X-ray, and Sunyaev–Zel’dovich catalogs, respectively, and so the majority of these clusters are new detections

  16. Low-ionization galaxies and evolution in a pilot survey up to z = 1

    Giraud, Edmond; Gu Qiusheng; Melnick, Jorge; Selman, Fernando; Quintana, Hernan; Toledo, Ignacio; Zelaya, Paula

    2011-01-01

    We present galactic spectroscopic data from a pencil beam of 10.75' x 7.5' centered on the X-ray cluster RXJ0054.0-2823 at z = 0.29. We study the spectral evolution of galaxies from z = 1 down to the cluster redshift in a magnitude-limited sample at R ≤ 23, for which the statistical properties of the sample are well understood. We divide emission-line galaxies into star-forming galaxies, Low Ionization Nuclear Emission line Regions (LINERs), and Seyferts by using emission-line ratios of [OII], Hβ, and [OIII], and derive stellar fractions from population synthesis models. We focus our analysis on absorption and low-ionization galaxies. For absorption-line galaxies, we recover the well-known result that these galaxies have had no detectable evolution since z ∼ 0.6 - 0.7, but we also find that in the range z = 0.65 - 1, at least 50% of the stars in bright absorption systems are younger than 2.5 Gyr Faint absorption-line galaxies in the cluster at z = 0.29 also had significant star formation during the previous 2 - 3 Gyr, but their brighter counterparts seem to be only composed of old stars. At z ∼ 0.8, our dynamically young cluster had a truncated red-sequence. This result seems to be consistent with a scenario where the final assembly of E/S0 took place at z < 1. In the volume-limited range 0.35 ≤ z ≤ 0.65, we find that 23% of the early-type galaxies have LINER-like spectra with Hβ in absorption and have a significant component of A stars. The vast majority of LINERs in our sample have significant populations of young and intermediate-aged stars and are thus not related to AGNs, but to the population of 'retired galaxies' recently identified by Cid Fernandes et al. in the Sloan Digital Sky Survey (SDSS). Early-type LINERs with various fractions of A stars and E+A galaxies appear to play an important role in the formation of the red sequence.

  17. THE HALO OCCUPATION DISTRIBUTION OF SDSS QUASARS

    Richardson, Jonathan; Chatterjee, Suchetana; Nagai, Daisuke; Zheng Zheng; Shen Yue

    2012-01-01

    We present an estimate of the projected two-point correlation function (2PCF) of quasars in the Sloan Digital Sky Survey (SDSS) over the full range of one- and two-halo scales, 0.02 h –1 Mpc p –1 Mpc. This was achieved by combining data from SDSS DR7 on large scales and Hennawi et al. (with appropriate statistical corrections) on small scales. Our combined clustering sample is the largest spectroscopic quasar clustering sample to date, containing ∼48, 000 quasars in the redshift range 0.4 ∼ sat = (7.4 ± 1.4) × 10 –4 , be satellites in dark matter halos. At z ∼ 1.4, the median masses of the host halos of central and satellite quasars are constrained to be M cen = 4.1 +0.3 –0.4 × 10 12 h –1 M ☉ and M sat = 3.6 +0.8 –1.0 × 10 14 h –1 M ☉ , respectively. To investigate the redshift evolution of the quasar-halo relationship, we also perform HOD modeling of the projected 2PCF measured by Shen et al. for SDSS quasars with median redshift 3.2. We find tentative evidence for an increase in the mass scale of quasar host halos—the inferred median mass of halos hosting central quasars at z ∼ 3.2 is M cen = 14.1 +5.8 –6.9 × 10 12 h –1 M ☉ . The cutoff profiles of the mean occupation functions of central quasars reveal that quasar luminosity is more tightly correlated with halo mass at higher redshifts. The average quasar duty cycle around the median host halo mass is inferred to be f q = 7.3 +0.6 –1.5 × 10 –4 at z ∼ 1.4 and f q = 8.6 +20.4 –7.2 × 10 –2 at z ∼ 3.2. We discuss the implications of our results for quasar evolution and quasar-galaxy co-evolution.

  18. Red Geyser: A New Class of Galaxy with Large-scale AGN-driven Winds

    Roy, Namrata; Bundy, Kevin; Cheung, Edmond; MaNGA Team

    2018-01-01

    A new class of quiescent (non-star-forming) galaxies harboring possible AGN-driven winds have been discovered using the spatially resolved optical spectroscopy from the ongoing SDSS-IV MaNGA (Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at Apache Point Observatory) survey. These galaxies named "red geysers" constitute 5%-10% of the local quiescent galaxy population and are characterized by narrow bisymmetric ionized gas emission patterns. These enhanced patterns are seen in equivalent width maps of Hα, [OIII] and other strong emission lines. They are co-aligned with the ionized gas velocity gradients but significantly misaligned with stellar velocity gradients. They also show very high gas velocity dispersions (~200 km/s). Considering these observations in light of models of the gravitational potential, Cheung et al. argued that red geysers host large-scale AGN-driven winds of ionized gas that may play a role in suppressing star formation at late times. In this work, we test the hypothesis that AGN activity is ultimately responsible for the red geyser phenomenon. We compare the nuclear radio activity of the red geysers to a matched control sample of galaxies of similar stellar mass, redshift, rest frame NUV–r color and axis ratio. and additionally, control for the presence of ionized gas. We have used 1.4 GHz radio continuum data from the VLA FIRST Survey to stack the radio flux from the red geyser sample and control sample. We find that the red geysers have a higher average radio flux than the control galaxies at > 3σ significance. Our sample is restricted to rest-frame NUV–r color > 5, thus ruling out possible radio emission due to star formation activity. We conclude that red geysers are associated with more active AGN, supporting a feedback picture in which episodic AGN activity drives large-scale but relatively weak ionized winds in many in many early-type galaxies.

  19. LUMINOSITY FUNCTIONS OF TYPE Ia SUPERNOVAE AND THEIR HOST GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY

    Yasuda, Naoki; Fukugita, Masataka

    2010-01-01

    The sample of 137 low-redshift type Ia supernovae (SNe Ia) with 0.05 ≤ z ≤ 0.3 obtained from the Sloan Digital Sky Survey (SDSS)-II supernova survey for the southern equatorial stripe of 300 deg 2 is used to derive the luminosity functions (LFs) of SNe Ia and of their host galaxies in the g, r, i passbands. We show that the LF of SNe Ia host galaxies matches well with that of galaxies in the general field, suggesting that the occurrence of SNe Ia does not favor a particular type of galaxy but is predominantly proportional to the luminosity of galaxies. The evidence is weak that the SNe rate varies with the color of host galaxies. The only evidence that points to possible correlation between the SN rate and star formation activity is that the SN rate in late-type galaxies is higher than that in early-type galaxies by 31% ± 35%. In our low-redshift sample, the component of type Ia SN rate that is proportional to star formation activity is not evident in the integrated SN rate, while our observation is compatible with the current two-component models. The sample contains eight SNe Ia whose host galaxies were not identified, but it is shown that their occurrence is consistent with them occurring in low-luminous galaxies beyond the survey. The LF of SNe Ia is approximately Gaussian with the full width at half-maximum being a factor of σ = 0.24 mag or 1.67 in luminosity. The Gaussian distribution becomes tighter if the ratio of extinction to reddening, R V , is lower than the characteristic value for the Milky Way and if luminosity is corrected for the light-curve shape. The average color excess is ∼0.07 mag, which is significantly smaller than reddening expected for field galaxies. This color excess does not vary with the distance of the SNe from the center of the host galaxy to 15 kpc. This suggests that the major part of the color excess appears to be either intrinsic or reddening that arises in the immediate environment of SNe, rather than interstellar

  20. SDSS J1254+0846: A BINARY QUASAR CAUGHT IN THE ACT OF MERGING

    Green, Paul J.; Cox, Thomas J.; Aldcroft, Thomas L.; Myers, Adam D.; Barkhouse, Wayne A.; Mulchaey, John S.; Bennert, Vardha N.

    2010-01-01

    We present the first luminous, spatially resolved binary quasar that clearly inhabits an ongoing galaxy merger. SDSS J125455.09+084653.9 and SDSS J125454.87+084652.1 (SDSS J1254+0846 hereafter) are two luminous z = 0.44 radio-quiet quasars, with a radial velocity difference of just 215 km s -1 , separated on the sky by 21 kpc in a disturbed host galaxy merger showing obvious tidal tails. The pair was targeted as part of a complete sample of binary quasar candidates with small transverse separations drawn from SDSS DR6 photometry. We present follow-up optical imaging which shows broad, symmetrical tidal arm features spanning some 75 kpc at the quasars' redshift. Previously, the triggering of two quasars during a merger had only been hypothesized but our observations provide strong evidence of such an event. SDSS J1254+0846, as a face-on, pre-coalescence merger hosting two luminous quasars separated by a few dozen kpc, provides a unique opportunity to probe quasar activity in an ongoing gas-rich merger. Numerical modeling suggests that the system consists of two massive disk galaxies prograde to their mutual orbit, caught during the first passage of an active merger. This demonstrates rapid black hole growth during the early stages of a merger between galaxies with pre-existing bulges. Neither of the two luminous nuclei show significant intrinsic absorption by gas or dust in our optical or X-ray observations, illustrating that not all merging quasars will be in an obscured, ultraluminous phase. We find that the Eddington ratio for the fainter component B is rather normal, while for the A component L/L Edd is quite (>3σ) high compared to quasars of similar luminosity and redshift, possibly evidence for strong merger-triggered accretion. More such mergers should be identifiable at higher redshifts using binary quasars as tracers.

  1. GALAXIES IN ΛCDM WITH HALO ABUNDANCE MATCHING: LUMINOSITY-VELOCITY RELATION, BARYONIC MASS-VELOCITY RELATION, VELOCITY FUNCTION, AND CLUSTERING

    Trujillo-Gomez, Sebastian; Klypin, Anatoly; Primack, Joel; Romanowsky, Aaron J.

    2011-01-01

    .e., stars and cold gas) of galaxies as a function of circular velocity with the available observations, again finding a very good agreement. The predicted circular velocity function (VF) is also in agreement with the galaxy VF from 80 to 400 km s –1 , using the HIPASS survey for late-type galaxies and Sloan Digital Sky Survey (SDSS) for early-type galaxies. However, in accord with other recent results, we find that the DM halos with V circ –1 are much more abundant than observed galaxies with the same V circ . Finally, we find that the two-point correlation function of bright galaxies in our model matches very well the results from the final data release of the SDSS, especially when a small amount of scatter is included in the HAM prescription.

  2. Millijansky radio variability in SDSS stripe 82

    Hodge, J. A.; Becker, R. H. [University of California, 1 Shields Avenue, Davis, CA 95616 (United States); White, R. L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Richards, G. T., E-mail: hodge@mpia.de [Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States)

    2013-06-01

    We report on a blind survey for extragalactic radio variability that was carried out by comparing two epochs of data from the Faint Images of the Radio Sky at Twenty centimeters survey with a third epoch from a new 1.4 GHz survey of SDSS Stripe 82. The three epochs are spaced seven years apart and have an overlapping area of 60 deg{sup 2}. We uncover 89 variable sources down to the millijansky level, 75 of which are newly identified, and we find no evidence for transient phenomena. This new sample of variable sources allows us to infer an upper limit to the mean characteristic timescale of active galactic nucleus radio variability of 14 yr. We find that only 1% of extragalactic sources have fractional variability f {sub var} > 3, while 44% of Galactic sources vary by this much. The variable sample contains a larger fraction of quasars than a comparable non-variable control sample, though the majority of the variable sources appear to be extended galaxies in the optical. This implies that either quasars are not the dominant contributor to the variability of the sample, or that the deep optical data allow us to detect the host galaxies of some low-z quasars. We use the new, higher resolution data to report on the morphology of the variable sources. Finally, we show that the fraction of sources that are variable remains constant or increases at low flux densities. This may imply that next generation radio surveys with telescopes like Australian Square Kilometer Array Pathfinder and MeerKAT will see a constant or even increasing fraction of variable sources down into the sub-millijansky regime.

  3. MaNGA: Mapping Nearby Galaxies at Apache Point Observatory

    Weijmans, A.-M.; MaNGA Team

    2016-10-01

    MaNGA (Mapping Nearby Galaxies at APO) is a galaxy integral-field spectroscopic survey within the fourth generation Sloan Digital Sky Survey (SDSS-IV). It will be mapping the composition and kinematics of gas and stars in 10,000 nearby galaxies, using 17 differently sized fiber bundles. MaNGA's goal is to provide new insights in galaxy formation and evolution, and to deliver a local benchmark for current and future high-redshift studies.

  4. The distributed development environment for SDSS software

    Berman, E.; Gurbani, V.; Mackinnon, B.; Newberg, H. Nicinski, T.; Petravick, D.; Pordes, R.; Sergey, G.; Stoughton, C.; Lupton, R.

    1994-04-01

    The authors present an integrated science software development environment, code maintenance and support system for the Sloan Digital Sky Survey (SDSS) now being actively used throughout the collaboration

  5. Galaxy Zoo: A Catalog of Overlapping Galaxy Pairs for Dust Studies

    Keel, William C.; Manning, Anna; Holwerda, Benne W.; Mezzoprete, Massimo; Lintott, Chris J.; Schawinski, Kevin; Gay, Pamela; Masters, Karen L.

    2012-01-01

    Analysis of galaxies with overlapping images offers a direct way to probe the distribution of dust extinction and its effects on the background light. We present a catalog of 1990 such galaxy pairs selected from the Sloan Digital Sky Survey (SDSS) by volunteers of the Galaxy Zoo project. We highlight subsamples which are particularly useful for retrieving such properties of the dust distribution as UV extinction, the extent perpendicular to the disk plane, and extinction in the inner parts of...

  6. The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III

    Aihara, Hiroaki; /Tokyo U.; Prieto, Carlos Allende; /Laguna U., Tenerife; An, Deokkeun; /Ewha Women' s U., Seoul; Anderson, Scott F.; /Washington U., Seattle, Astron. Dept.; Aubourg, Eric; /APC, Paris /DAPNIA, Saclay; Balbinot, Eduardo; /Rio Grande do Sul U. /Rio de Janeiro Observ.; Beers, Timothy C.; /Michigan State U.; Berlind, Andreas A.; /Vanderbilt U.; Bickerton, Steven J.; /Princeton U.; Bizyaev, Dmitry; /Apache Point Observ.; Blanton, Michael R.; /New York U., CCPP /Penn State U.

    2011-01-01

    The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Ly{alpha} forest, and a radial velocity search for planets around {approx}8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes 5-band imaging of roughly 5200 deg{sup 2} in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg{sup 2}, or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galactic latitudes. All the more than half a million stellar spectra obtained with the SDSS spectrograph have been reprocessed through an improved stellar parameters pipeline, which has better determination of metallicity for high metallicity stars.

  7. Properties of optically selected BL Lacertae candidates from the SDSS

    Kügler, S. D.; Nilsson, K.; Heidt, J.; Esser, J.; Schultz, T.

    2014-09-01

    Context. Deep optical surveys open the avenue for finding large numbers of BL Lac objects that are hard to identify because they lack the unique properties classifying them as such. While radio or X-ray surveys typically reveal dozens of sources, recent compilations based on optical criteria alone have increased the number of BL Lac candidates considerably. However, these compilations are subject to biases and may contain a substantial number of contaminating sources. Aims: In this paper we extend our analysis of 182 optically selected BL Lac object candidates from the SDSS with respect to an earlier study. The main goal is to determine the number of bona fide BL Lac objects in this sample. Methods: We examine their variability characteristics, determine their broad-band radio-UV spectral energy distributions (SEDs), and search for the presence of a host galaxy. In addition we present new optical spectra for 27 targets with improved signal-to-noise ratio with respect to the SDSS spectra. Results: At least 59% of our targets have shown variability between SDSS DR2 and our observations by more than 0.1-0.27 mag depending on the telescope used. A host galaxy was detected in 36% of our targets. The host galaxy type and luminosities are consistent with earlier studies of BL Lac host galaxies. Simple fits to broad-band SEDs for 104 targets of our sample derived synchrotron peak frequencies between 13.5 ≤ log 10(νpeak) ≤ 16 with a peak at log 10 ~ 14.5. Our new optical spectra do not reveal any new redshift for any of our objects. Thus the sample contains a large number of bona fide BL Lac objects and seems to contain a substantial fraction of intermediate-frequency peaked BL Lacs. Based on observations collected with the NTT on La Silla (Chile) operated by the European Southern Observatory under proposal 082.B-0133.Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA), operated jointly by the Max-Planck-Institut für Astronomie and the

  8. Blueberry Galaxies: The Lowest Mass Young Starbursts

    Yang, Huan; Malhotra, Sangeeta; Rhoads, James E.; Wang, Junxian

    2017-09-01

    Searching for extreme emission line galaxies allows us to find low-mass metal-poor galaxies that are good analogs of high redshift Lyα emitting galaxies. These low-mass extreme emission line galaxies are also potential Lyman-continuum leakers. Finding them at very low redshifts (z≲ 0.05) allows us to be sensitive to even lower stellar masses and metallicities. We report on a sample of extreme emission line galaxies at z≲ 0.05 (blueberry galaxies). We selected them from SDSS broadband images on the basis of their broadband colors and studied their properties with MMT spectroscopy. From the entire SDSS DR12 photometric catalog, we found 51 photometric candidates. We spectroscopically confirm 40 as blueberry galaxies. (An additional seven candidates are contaminants, and four remain without spectra.) These blueberries are dwarf starburst galaxies with very small sizes (<1 kpc) and very high ionization ([O III]/[O II] ˜ 10-60). They also have some of the lowest stellar masses ({log}(M/{M}⊙ )˜ 6.5{--}7.5) and lowest metallicities (7.1< 12+{log}({{O}}/{{H}})< 7.8) of starburst galaxies. Thus, they are small counterparts to green pea galaxies and high redshift Lyα emitting galaxies.

  9. Evidence for a Multiphase ISM in Early Type Galaxies and Elliptical Galaxies with Strong Radio Continuum

    Kim, Dong Woo

    1997-01-01

    We have observed NGC 1316 (Fornax A) with the ROSAT HRI. In this paper, we present the results of these observations and we complement them with the spectral analysis of the archival PSPC data. The spectral properties suggest the presence of a significant component of thermal X-ray emission (greater than 60%), amounting to approx. 10(exp 9) solar mass of hot ISM. Within 3 feet from the nucleus of NGC 1316, the HRI X-ray surface brightness falls as r(exp -2) following the stellar light. In the inner approx. 30 inch., however, the X-ray surface brightness is significantly elongated, contrary to the distribution of stellar light, which is significantly rounder within 10 inch. This again argues for a non-stellar origin of the X-ray emission. This flattened X-ray feature is suggestive of either the disk-like geometry of a rotating cooling flow and/or the presence of extended, elongated dark matter. By comparing the morphology of the X-ray emission with the distribution of optical dust patches, we find that the X-ray emission is significantly reduced at the locations where the dust patches are more pronounced, indicating that at least some of the X-ray photons are absorbed by the cold ISM. We also compare the distribution of the hot and cold ISM with that of the ionized gas, using recently obtained H(sub alpha) CCD data. We find that the ionized gas is distributed roughly along the dust patches and follows the large scale X-ray distribution at r greater than 1 foot from the nucleus. However, there is no one-to-one correspondence between ionized gas and hot gas. Both morphological relations and kinematics suggest different origins for hot and cold ISM. The radio jets in projection appear to pass perpendicularly through the central X-ray ellipsoid. Comparison of thermal and radio pressures suggests that the radio jets are confined by the surrounding hot gaseous medium.

  10. H I-SELECTED GALAXIES IN THE SLOAN DIGITAL SKY SURVEY. I. OPTICAL DATA

    West, Andrew A.; Garcia-Appadoo, Diego A.; Dalcanton, Julianne J.; Ivezic, Zeljko; Bentz, Misty C.; Disney, Mike J.; Rockosi, Constance M.; Brinkmann, J.

    2010-01-01

    We present the optical data for 195 H I-selected galaxies that fall within both the Sloan Digital Sky Survey (SDSS) and the Parkes Equatorial Survey (ES). The photometric quantities have been independently recomputed for our sample using a new photometric pipeline optimized for large galaxies, thus correcting for SDSS's limited reliability for automatic photometry of angularly large or low surface brightness (LSB) galaxies. We outline the magnitude of the uncertainty in the SDSS catalog-level photometry and derive a quantitative method for correcting the over-sky subtraction in the SDSS photometric pipeline. The main thrust of this paper is to present the ES/SDSS sample and discuss the methods behind the improved photometry, which will be used in future scientific analysis. We present the overall optical properties of the sample and briefly compare to a volume-limited, optically selected sample. Compared to the optically selected SDSS sample (in the similar volume), H I-selected galaxies are bluer and more luminous (fewer dwarf ellipticals and more star formation). However, compared to typical SDSS galaxy studies, which have their own selection effect, our sample is bluer, fainter, and less massive.

  11. Dark Energy Survey Year 1 Results: Calibration of redMaGiC Redshift Distributions in DES and SDSS from Cross-Correlations

    Cawthon, R.; et al.

    2017-12-19

    We present calibrations of the redshift distributions of redMaGiC galaxies in the Dark Energy Survey Year 1 (DES Y1) and Sloan Digital Sky Survey (SDSS) DR8 data. These results determine the priors of the redshift distribution of redMaGiC galaxies, which were used for galaxy clustering measurements and as lenses for galaxy-galaxy lensing measurements in DES Y1 cosmological analyses. We empirically determine the bias in redMaGiC photometric redshift estimates using angular cross-correlations with Baryon Oscillation Spectroscopic Survey (BOSS) galaxies. For DES, we calibrate a single parameter redshift bias in three photometric redshift bins: $z \\in[0.15,0.3]$, [0.3,0.45], and [0.45,0.6]. Our best fit results in each bin give photometric redshift biases of $|\\Delta z|<0.01$. To further test the redMaGiC algorithm, we apply our calibration procedure to SDSS redMaGiC galaxies, where the statistical precision of the cross-correlation measurement is much higher due to a greater overlap with BOSS galaxies. For SDSS, we also find best fit results of $|\\Delta z|<0.01$. We compare our results to other analyses of redMaGiC photometric redshifts.

  12. Mass Models and Environment of the New Quadruply Lensed Quasar SDSS J1330+1810

    Oguri, Masamune; Inada, Naohisa; Blackburne, Jeffrey A.; Shin, Min-Su; Kayo, Issha; Strauss, Michael A.; Schneider, Donald P.; York, Donald G.

    2008-09-09

    We present the discovery of a new quadruply lensed quasar. The lens system, SDSS J1330+1810 at z{sub s} = 1.393, was identified as a lens candidate from the spectroscopic sample of the Sloan Digital Sky Survey. Optical and near-infrared images clearly show four quasar images with a maximum image separation of 1.76 inch, as well as a bright lensing galaxy. We measure a redshift of the lensing galaxy of z{sub 1} = 0.373 from absorption features in the spectrum. We find a foreground group of galaxies at z = 0.31 centred {approx} 120 inch southwest of the lens system. Simple mass models fit the data quite well, including the flux ratios between images, although the lens galaxy appears to be {approx} 1 mag brighter than expected by the Faber-Jackson relation. Our mass modeling suggests that shear from nearby structure is affecting the lens potential.

  13. Photometric redshift requirements for lens galaxies in galaxy-galaxy lensing analyses

    Nakajima, R.; Mandelbaum, R.; Seljak, U.; Cohn, J. D.; Reyes, R.; Cool, R.

    2012-03-01

    Weak gravitational lensing is a valuable probe of galaxy formation and cosmology. Here we quantify the effects of using photometric redshifts (photo-z) in galaxy-galaxy lensing, for both sources and lenses, both for the immediate goal of using galaxies with photo-z as lenses in the Sloan Digital Sky Survey (SDSS) and as a demonstration of methodology for large, upcoming weak lensing surveys that will by necessity be dominated by lens samples with photo-z. We calculate the bias in the lensing mass calibration as well as consequences for absolute magnitude (i.e. k-corrections) and stellar mass estimates for a large sample of SDSS Data Release 8 (DR8) galaxies. The redshifts are obtained with the template-based photo-z code ZEBRA on the SDSS DR8 ugriz photometry. We assemble and characterize the calibration samples (˜9000 spectroscopic redshifts from four surveys) to obtain photometric redshift errors and lensing biases corresponding to our full SDSS DR8 lens and source catalogues. Our tests of the calibration sample also highlight the impact of observing conditions in the imaging survey when the spectroscopic calibration covers a small fraction of its footprint; atypical imaging conditions in calibration fields can lead to incorrect conclusions regarding the photo-z of the full survey. For the SDSS DR8 catalogue, we find σΔz/(1+z)= 0.096 and 0.113 for the lens and source catalogues, with flux limits of r= 21 and 21.8, respectively. The photo-z bias and scatter is a function of photo-z and template types, which we exploit to apply photo-z quality cuts. By using photo-z rather than spectroscopy for lenses, dim blue galaxies and L* galaxies up to z˜ 0.4 can be used as lenses, thus expanding into unexplored areas of parameter space. We also explore the systematic uncertainty in the lensing signal calibration when using source photo-z, and both lens and source photo-z; given the size of existing training samples, we can constrain the lensing signal calibration (and

  14. Angular momentum-large-scale structure alignments in ΛCDM models and the SDSS

    Paz, Dante J.; Stasyszyn, Federico; Padilla, Nelson D.

    2008-09-01

    We study the alignments between the angular momentum of individual objects and the large-scale structure in cosmological numerical simulations and real data from the Sloan Digital Sky Survey, Data Release 6 (SDSS-DR6). To this end, we measure anisotropies in the two point cross-correlation function around simulated haloes and observed galaxies, studying separately the one- and two-halo regimes. The alignment of the angular momentum of dark-matter haloes in Λ cold dark matter (ΛCDM) simulations is found to be dependent on scale and halo mass. At large distances (two-halo regime), the spins of high-mass haloes are preferentially oriented in the direction perpendicular to the distribution of matter; lower mass systems show a weaker trend that may even reverse to show an angular momentum in the plane of the matter distribution. In the one-halo term regime, the angular momentum is aligned in the direction perpendicular to the matter distribution; the effect is stronger than for the one-halo term and increases for higher mass systems. On the observational side, we focus our study on galaxies in the SDSS-DR6 with elongated apparent shapes, and study alignments with respect to the major semi-axis. We study five samples of edge-on galaxies; the full SDSS-DR6 edge-on sample, bright galaxies, faint galaxies, red galaxies and blue galaxies (the latter two consisting mainly of ellipticals and spirals, respectively). Using the two-halo term of the projected correlation function, we find an excess of structure in the direction of the major semi-axis for all samples; the red sample shows the highest alignment (2.7 +/- 0.8per cent) and indicates that the angular momentum of flattened spheroidals tends to be perpendicular to the large-scale structure. These results are in qualitative agreement with the numerical simulation results indicating that the angular momentum of galaxies could be built up as in the Tidal Torque scenario. The one-halo term only shows a significant alignment

  15. Exploring the SDSS Data Set with Linked Scatter Plots. I. EMP, CEMP, and CV Stars

    Carbon, Duane F.; Henze, Christopher; Nelson, Bron C., E-mail: Duane.F.Carbon@nasa.gov [NASA Ames Research Center, NASA Advanced Supercomputing Facility, Moffett Field, CA, 94035-1000 (United States)

    2017-02-01

    We present the results of a search for extremely metal-poor (EMP), carbon-enhanced metal-poor (CEMP), and cataclysmic variable (CV) stars using a new exploration tool based on linked scatter plots (LSPs). Our approach is especially designed to work with very large spectrum data sets such as the SDSS, LAMOST, RAVE, and Gaia data sets, and it can be applied to stellar, galaxy, and quasar spectra. As a demonstration, we conduct our search using the SDSS DR10 data set. We first created a 3326-dimensional phase space containing nearly 2 billion measures of the strengths of over 1600 spectral features in 569,738 SDSS stars. These measures capture essentially all the stellar atomic and molecular species visible at the resolution of SDSS spectra. We show how LSPs can be used to quickly isolate and examine interesting portions of this phase space. To illustrate, we use LSPs coupled with cuts in selected portions of phase space to extract EMP stars, CEMP stars, and CV stars. We present identifications for 59 previously unrecognized candidate EMP stars and 11 previously unrecognized candidate CEMP stars. We also call attention to 2 candidate He ii emission CV stars found by the LSP approach that have not yet been discussed in the literature.

  16. Kinematically Decoupled Cores in Dwarf (Elliptical) Galaxies

    Toloba, E.; Peletier, R. F.; Guhathakurta, P.; van de Ven, G.; Boissier, S.; Boselli, A.; Brok, M. d.; Falcón-Barroso, J.; Hensler, G.; Janz, J.; Laurikainen, E.; Lisker, T.; Paudel, S.; Ryś, A.; Salo, H.

    An overview is given of what we know about the frequency of kinematically decoupled cores in dwarf elliptical galaxies. New observations show that kinematically decoupled cores happen just as often in dwarf elliptical as in ordinary early-type galaxies. This has important consequences for the

  17. Colours and morphology of spiral galaxies

    Wyse, R.F.G.

    1981-01-01

    Tinsley has proposed that late-type spirals have relatively more non-luminous material than early-type spirals. A re-examination of the data indicates that this proposal is equally consistent with dark matter being more dominant in barred galaxies than in unbarred galaxies. Neither conclusion can be firm, since the dataset is far from ideal. (author)

  18. THE ELEVENTH AND TWELFTH DATA RELEASES OF THE SLOAN DIGITAL SKY SURVEY: FINAL DATA FROM SDSS-III

    Alam, Shadab; Albareti, Franco D.; Prieto, Carlos Allende; Anders, F.; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Armengaud, Eric; Aubourg, Éric; Bautista, Julian E.; Bailey, Stephen; Basu, Sarbani; Beaton, Rachael L.; Beers, Timothy C.

    2015-01-01

    The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg 2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg 2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg 2 ; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra

  19. The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III

    Alam, Shadab; Albareti, Franco D.; Allende Prieto, Carlos; Anders, F.; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Armengaud, Eric; Aubourg, Éric; Bailey, Stephen; Basu, Sarbani; Bautista, Julian E.; Beaton, Rachael L.; Beers, Timothy C.; Bender, Chad F.; Berlind, Andreas A.; Beutler, Florian; Bhardwaj, Vaishali; Bird, Jonathan C.; Bizyaev, Dmitry; Blake, Cullen H.; Blanton, Michael R.; Blomqvist, Michael; Bochanski, John J.; Bolton, Adam S.; Bovy, Jo; Shelden Bradley, A.; Brandt, W. N.; Brauer, D. E.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Burden, Angela; Burtin, Etienne; Busca, Nicolás G.; Cai, Zheng; Capozzi, Diego; Carnero Rosell, Aurelio; Carr, Michael A.; Carrera, Ricardo; Chambers, K. C.; Chaplin, William James; Chen, Yen-Chi; Chiappini, Cristina; Chojnowski, S. Drew; Chuang, Chia-Hsun; Clerc, Nicolas; Comparat, Johan; Covey, Kevin; Croft, Rupert A. C.; Cuesta, Antonio J.; Cunha, Katia; da Costa, Luiz N.; Da Rio, Nicola; Davenport, James R. A.; Dawson, Kyle S.; De Lee, Nathan; Delubac, Timothée; Deshpande, Rohit; Dhital, Saurav; Dutra-Ferreira, Letícia; Dwelly, Tom; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Ellsworth, Tristan; Elsworth, Yvonne; Epstein, Courtney R.; Eracleous, Michael; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Fernández-Alvar, Emma; Feuillet, Diane; Filiz Ak, Nurten; Finley, Hayley; Finoguenov, Alexis; Flaherty, Kevin; Fleming, Scott W.; Font-Ribera, Andreu; Foster, Jonathan; Frinchaboy, Peter M.; Galbraith-Frew, J. G.; García, Rafael A.; García-Hernández, D. A.; García Pérez, Ana E.; Gaulme, Patrick; Ge, Jian; Génova-Santos, R.; Georgakakis, A.; Ghezzi, Luan; Gillespie, Bruce A.; Girardi, Léo; Goddard, Daniel; Gontcho, Satya Gontcho A.; González Hernández, Jonay I.; Grebel, Eva K.; Green, Paul J.; Grieb, Jan Niklas; Grieves, Nolan; Gunn, James E.; Guo, Hong; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne L.; Hayden, Michael; Hearty, Fred R.; Hekker, Saskia; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Honscheid, Klaus; Huber, Daniel; Huehnerhoff, Joseph; Ivans, Inese I.; Jiang, Linhua; Johnson, Jennifer A.; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco; Klaene, Mark A.; Knapp, Gillian R.; Kneib, Jean-Paul; Koenig, Xavier P.; Lam, Charles R.; Lan, Ting-Wen; Lang, Dustin; Laurent, Pierre; Le Goff, Jean-Marc; Leauthaud, Alexie; Lee, Khee-Gan; Lee, Young Sun; Licquia, Timothy C.; Liu, Jian; Long, Daniel C.; López-Corredoira, Martín; Lorenzo-Oliveira, Diego; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; Mack, Claude E., III; Mahadevan, Suvrath; Maia, Marcio A. G.; Majewski, Steven R.; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A.; Manera, Marc; Mao, Qingqing; Maraston, Claudia; Marchwinski, Robert C.; Margala, Daniel; Martell, Sarah L.; Martig, Marie; Masters, Karen L.; Mathur, Savita; McBride, Cameron K.; McGehee, Peregrine M.; McGreer, Ian D.; McMahon, Richard G.; Ménard, Brice; Menzel, Marie-Luise; Merloni, Andrea; Mészáros, Szabolcs; Miller, Adam A.; Miralda-Escudé, Jordi; Miyatake, Hironao; Montero-Dorta, Antonio D.; More, Surhud; Morganson, Eric; Morice-Atkinson, Xan; Morrison, Heather L.; Mosser, Benôit; Muna, Demitri; Myers, Adam D.; Nandra, Kirpal; Newman, Jeffrey A.; Neyrinck, Mark; Nguyen, Duy Cuong; Nichol, Robert C.; Nidever, David L.; Noterdaeme, Pasquier; Nuza, Sebastián E.; O'Connell, Julia E.; O'Connell, Robert W.; O'Connell, Ross; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Audrey E.; Oravetz, Daniel J.; Osumi, Keisuke; Owen, Russell; Padgett, Deborah L.; Padmanabhan, Nikhil; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K.; Pâris, Isabelle; Park, Changbom; Pattarakijwanich, Petchara; Pellejero-Ibanez, M.; Pepper, Joshua; Percival, Will J.; Pérez-Fournon, Ismael; P´rez-Ra`fols, Ignasi; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc H.; Porto de Mello, Gustavo F.; Prada, Francisco; Prakash, Abhishek; Price-Whelan, Adrian M.; Protopapas, Pavlos; Raddick, M. Jordan; Rahman, Mubdi; Reid, Beth A.; Rich, James; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodrigues, Thaíse S.; Rodríguez-Torres, Sergio; Roe, Natalie A.; Ross, Ashley J.; Ross, Nicholas P.; Rossi, Graziano; Ruan, John J.; Rubiño-Martín, J. A.; Rykoff, Eli S.; Salazar-Albornoz, Salvador; Salvato, Mara; Samushia, Lado; Sánchez, Ariel G.; Santiago, Basílio; Sayres, Conor; Schiavon, Ricardo P.; Schlegel, David J.; Schmidt, Sarah J.; Schneider, Donald P.; Schultheis, Mathias; Schwope, Axel D.; Scóccola, C. G.; Scott, Caroline; Sellgren, Kris; Seo, Hee-Jong; Serenelli, Aldo; Shane, Neville; Shen, Yue; Shetrone, Matthew; Shu, Yiping; Silva Aguirre, V.; Sivarani, Thirupathi; Skrutskie, M. F.; Slosar, Anže; Smith, Verne V.; Sobreira, Flávia; Souto, Diogo; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Strauss, Michael A.; Streblyanska, Alina; Suzuki, Nao; Swanson, Molly E. C.; Tan, Jonathan C.; Tayar, Jamie; Terrien, Ryan C.; Thakar, Aniruddha R.; Thomas, Daniel; Thomas, Neil; Thompson, Benjamin A.; Tinker, Jeremy L.; Tojeiro, Rita; Troup, Nicholas W.; Vargas-Magaña, Mariana; Vazquez, Jose A.; Verde, Licia; Viel, Matteo; Vogt, Nicole P.; Wake, David A.; Wang, Ji; Weaver, Benjamin A.; Weinberg, David H.; Weiner, Benjamin J.; White, Martin; Wilson, John C.; Wisniewski, John P.; Wood-Vasey, W. M.; Ye`che, Christophe; York, Donald G.; Zakamska, Nadia L.; Zamora, O.; Zasowski, Gail; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng; Zhou, Xu; Zhou, Zhimin; Zou, Hu; Zhu, Guangtun

    2015-07-01

    The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg2; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra.

  20. The eleventh and twelfth data release of the Sloan Digital Sky Survey: Final data from SDSS-III

    Alam, Shadab; Albareti, Franco D.; Prieto, Carlos Allende; Anders, F.; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Armengaud, Eric; Aubourg, Éric; Bailey, Stephen; Basu, Sarbani; Bautista, Julian E.; Beaton, Rachael L.; Beers, Timothy C.; Bender, Chad F.; Berlind, Andreas A.; Beutler, Florian; Bhardwaj, Vaishali; Bird, Jonathan C.; Bizyaev, Dmitry; Blake, Cullen H.; Blanton, Michael R.; Blomqvist, Michael; Bochanski, John J.; Bolton, Adam S.; Bovy, Jo; Bradley, A. Shelden; Brandt, W. N.; Brauer, D. E.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Burden, Angela; Burtin, Etienne; Busca, Nicolás G.; Cai, Zheng; Capozzi, Diego; Rosell, Aurelio Carnero; Carr, Michael A.; Carrera, Ricardo; Chambers, K. C.; Chaplin, William James; Chen, Yen-Chi; Chiappini, Cristina; Chojnowski, S. Drew; Chuang, Chia-Hsun; Clerc, Nicolas; Comparat, Johan; Covey, Kevin; Croft, Rupert A. C.; Cuesta, Antonio J.; Cunha, Katia; Costa, Luiz N. da; Rio, Nicola Da; Davenport, James R. A.; Dawson, Kyle S.; Lee, Nathan De; Delubac, Timothée; Deshpande, Rohit; Dhital, Saurav; Dutra-Ferreira, Letícia; Dwelly, Tom; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Ellsworth, Tristan; Elsworth, Yvonne; Epstein, Courtney R.; Eracleous, Michael; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Fernández-Alvar, Emma; Feuillet, Diane; Ak, Nurten Filiz; Finley, Hayley; Finoguenov, Alexis; Flaherty, Kevin; Fleming, Scott W.; Font-Ribera, Andreu; Foster, Jonathan; Frinchaboy, Peter M.; Galbraith-Frew, J. G.; García, Rafael A.; García-Hernández, D. A.; Pérez, Ana E. García; Gaulme, Patrick; Ge, Jian; Génova-Santos, R.; Georgakakis, A.; Ghezzi, Luan; Gillespie, Bruce A.; Girardi, Léo; Goddard, Daniel; Gontcho, Satya Gontcho A.; Hernández, Jonay I. González; Grebel, Eva K.; Green, Paul J.; Grieb, Jan Niklas; Grieves, Nolan; Gunn, James E.; Guo, Hong; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne L.; Hayden, Michael; Hearty, Fred R.; Hekker, Saskia; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Honscheid, Klaus; Huber, Daniel; Huehnerhoff, Joseph; Ivans, Inese I.; Jiang, Linhua; Johnson, Jennifer A.; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco; Klaene, Mark A.; Knapp, Gillian R.; Kneib, Jean-Paul; Koenig, Xavier P.; Lam, Charles R.; Lan, Ting-Wen; Lang, Dustin; Laurent, Pierre; Goff, Jean-Marc Le; Leauthaud, Alexie; Lee, Khee-Gan; Lee, Young Sun; Licquia, Timothy C.; Liu, Jian; Long, Daniel C.; López-Corredoira, Martín; Lorenzo-Oliveira, Diego; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; III, Claude E. Mack; Mahadevan, Suvrath; Maia, Marcio A. G.; Majewski, Steven R.; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A.; Manera, Marc; Mao, Qingqing; Maraston, Claudia; Marchwinski, Robert C.; Margala, Daniel; Martell, Sarah L.; Martig, Marie; Masters, Karen L.; Mathur, Savita; McBride, Cameron K.; McGehee, Peregrine M.; McGreer, Ian D.; McMahon, Richard G.; Ménard, Brice; Menzel, Marie-Luise; Merloni, Andrea; Mészáros, Szabolcs; Miller, Adam A.; Miralda-Escudé, Jordi; Miyatake, Hironao; Montero-Dorta, Antonio D.; More, Surhud; Morganson, Eric; Morice-Atkinson, Xan; Morrison, Heather L.; Mosser, Benôit; Muna, Demitri; Myers, Adam D.; Nandra, Kirpal; Newman, Jeffrey A.; Neyrinck, Mark; Nguyen, Duy Cuong; Nichol, Robert C.; Nidever, David L.; Noterdaeme, Pasquier; Nuza, Sebastián E.; O’Connell, Julia E.; O’Connell, Robert W.; O’Connell, Ross; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Audrey E.; Oravetz, Daniel J.; Osumi, Keisuke; Owen, Russell; Padgett, Deborah L.; Padmanabhan, Nikhil; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K.; Pâris, Isabelle; Park, Changbom; Pattarakijwanich, Petchara; Pellejero-Ibanez, M.; Pepper, Joshua; Percival, Will J.; Pérez-Fournon, Ismael; Pe´rez-Ra`fols, Ignasi; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc H.; Mello, Gustavo F. Porto de; Prada, Francisco; Prakash, Abhishek; Price-Whelan, Adrian M.; Protopapas, Pavlos; Raddick, M. Jordan; Rahman, Mubdi; Reid, Beth A.; Rich, James; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodrigues, Thaíse S.; Rodríguez-Torres, Sergio; Roe, Natalie A.; Ross, Ashley J.; Ross, Nicholas P.; Rossi, Graziano; Ruan, John J.; Rubiño-Martín, J. A.; Rykoff, Eli S.; Salazar-Albornoz, Salvador; Salvato, Mara; Samushia, Lado; Sánchez, Ariel G.; Santiago, Basílio; Sayres, Conor; Schiavon, Ricardo P.; Schlegel, David J.; Schmidt, Sarah J.; Schneider, Donald P.; Schultheis, Mathias; Schwope, Axel D.; Scóccola, C. G.; Scott, Caroline; Sellgren, Kris; Seo, Hee-Jong; Serenelli, Aldo; Shane, Neville; Shen, Yue; Shetrone, Matthew; Shu, Yiping; Aguirre, V. Silva; Sivarani, Thirupathi; Skrutskie, M. F.; Slosar, Anže; Smith, Verne V.; Sobreira, Flávia; Souto, Diogo; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Strauss, Michael A.; Streblyanska, Alina; Suzuki, Nao; Swanson, Molly E. C.; Tan, Jonathan C.; Tayar, Jamie; Terrien, Ryan C.; Thakar, Aniruddha R.; Thomas, Daniel; Thomas, Neil; Thompson, Benjamin A.; Tinker, Jeremy L.; Tojeiro, Rita; Troup, Nicholas W.; Vargas-Magaña, Mariana; Vazquez, Jose A.; Verde, Licia; Viel, Matteo; Vogt, Nicole P.; Wake, David A.; Wang, Ji; Weaver, Benjamin A.; Weinberg, David H.; Weiner, Benjamin J.; White, Martin; Wilson, John C.; Wisniewski, John P.; Wood-Vasey, W. M.; Ye`che, Christophe; York, Donald G.; Zakamska, Nadia L.; Zamora, O.; Zasowski, Gail; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng; Zhou (周旭), Xu; Zhou (周志民), Zhimin; Zou (邹虎), Hu; Zhu, Guangtun

    2015-07-20

    The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg2; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra.

  1. INTERACTIONS OF GALAXIES IN THE GALAXY CLUSTER ENVIRONMENT

    Park, Changbom; Hwang, Ho Seong

    2009-01-01

    We study the dependence of galaxy properties on the clustercentric radius and the environment attributed to the nearest neighbor galaxy using the Sloan Digital Sky Survey galaxies associated with the Abell galaxy clusters. We find that there exists a characteristic scale where the properties of galaxies suddenly start to depend on the clustercentric radius at fixed neighbor environment. The characteristic scale is 1-3 times the cluster virial radius depending on galaxy luminosity. Existence of the characteristic scale means that the local galaxy number density is not directly responsible for the morphology-density relation in clusters because the local density varies smoothly with the clustercentric radius and has no discontinuity in general. What is really working in clusters is the morphology-clustercentric radius-neighbor environment relation, where the neighbor environment means both neighbor morphology and the local mass density attributed to the neighbor. The morphology-density relation appears working only because of the statistical correlation between the nearest neighbor distance and the local galaxy number density. We find strong evidence that the hydrodynamic interactions with nearby early-type galaxies is the main drive to quenching star formation activity of late-type galaxies in clusters. The hot cluster gas seems to play at most a minor role down to one tenth of the cluster virial radius. We also find that the viable mechanisms which can account for the clustercentric radius dependence of the structural and internal kinematics parameters are harassment and interaction of galaxies with the cluster potential. The morphology transformation of the late-type galaxies in clusters seems to have taken place through both galaxy-galaxy hydrodynamic interactions and galaxy-cluster/galaxy-galaxy gravitational interactions.

  2. INTERACTIONS OF GALAXIES IN THE GALAXY CLUSTER ENVIRONMENT

    Park, Changbom; Hwang, Ho Seong [School of Physics, Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of)], E-mail: cbp@kias.re.kr, E-mail: hshwang@kias.re.kr

    2009-07-10

    We study the dependence of galaxy properties on the clustercentric radius and the environment attributed to the nearest neighbor galaxy using the Sloan Digital Sky Survey galaxies associated with the Abell galaxy clusters. We find that there exists a characteristic scale where the properties of galaxies suddenly start to depend on the clustercentric radius at fixed neighbor environment. The characteristic scale is 1-3 times the cluster virial radius depending on galaxy luminosity. Existence of the characteristic scale means that the local galaxy number density is not directly responsible for the morphology-density relation in clusters because the local density varies smoothly with the clustercentric radius and has no discontinuity in general. What is really working in clusters is the morphology-clustercentric radius-neighbor environment relation, where the neighbor environment means both neighbor morphology and the local mass density attributed to the neighbor. The morphology-density relation appears working only because of the statistical correlation between the nearest neighbor distance and the local galaxy number density. We find strong evidence that the hydrodynamic interactions with nearby early-type galaxies is the main drive to quenching star formation activity of late-type galaxies in clusters. The hot cluster gas seems to play at most a minor role down to one tenth of the cluster virial radius. We also find that the viable mechanisms which can account for the clustercentric radius dependence of the structural and internal kinematics parameters are harassment and interaction of galaxies with the cluster potential. The morphology transformation of the late-type galaxies in clusters seems to have taken place through both galaxy-galaxy hydrodynamic interactions and galaxy-cluster/galaxy-galaxy gravitational interactions.

  3. Interpretation of galaxy counts

    Tinsely, B.M.

    1980-01-01

    New models are presented for the interpretation of recent counts of galaxies to 24th magnitude, and predictions are shown to 28th magnitude for future comparison with data from the Space Telescope. The results supersede earlier, more schematic models by the author. Tyson and Jarvis found in their counts a ''local'' density enhancement at 17th magnitude, on comparison with the earlier models; the excess is no longer significant when a more realistic mixture of galaxy colors is used. Bruzual and Kron's conclusion that Kron's counts show evidence for evolution at faint magnitudes is confirmed, and it is predicted that some 23d magnitude galaxies have redshifts greater than unity. These may include spheroidal systems, elliptical galaxies, and the bulges of early-type spirals and S0's, seen during their primeval rapid star formation

  4. Separating intrinsic alignment and galaxy-galaxy lensing

    Blazek, Jonathan; Seljak, Uroš; Mandelbaum, Rachel; Nakajima, Reiko

    2012-01-01

    The coherent physical alignment of galaxies is an important systematic for gravitational lensing studies as well as a probe of the physical mechanisms involved in galaxy formation and evolution. We develop a formalism for treating this intrinsic alignment (IA) in the context of galaxy-galaxy lensing and present an improved method for measuring IA contamination, which can arise when sources physically associated with the lens are placed behind the lens due to photometric redshift scatter. We apply the technique to recent Sloan Digital Sky Survey (SDSS) measurements of Luminous Red Galaxy lenses and typical ( ∼ L * ) source galaxies with photometric redshifts selected from the SDSS imaging data. Compared to previous measurements, this method has the advantage of being fully self-consistent in its treatment of the IA and lensing signals, solving for the two simultaneously. We find an IA signal consistent with zero, placing tight constraints on both the magnitude of the IA effect and its potential contamination to the lensing signal. While these constraints depend on source selection and redshift quality, the method can be applied to any measurement that uses photometric redshifts. We obtain a model-independent upper-limit of roughly 10% IA contamination for projected separations of r p ≈ 0.1–10 h −1 Mpc. With more stringent photo-z cuts and reasonable assumptions about the physics of intrinsic alignments, this upper limit is reduced to 1–2%. These limits are well below the statistical error of the current lensing measurements. Our results suggest that IA will not present intractable challenges to the next generation of galaxy-galaxy lensing experiments, and the methods presented here should continue to aid in our understanding of alignment processes and in the removal of IA from the lensing signal

  5. COMPARING H{alpha} AND H I SURVEYS AS MEANS TO A COMPLETE LOCAL GALAXY CATALOG IN THE ADVANCED LIGO/VIRGO ERA

    Metzger, Brian D. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08542 (United States); Kaplan, David L. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211 (United States); Berger, Edo, E-mail: bmetzger@astro.princeton.edu, E-mail: kaplan@uwm.edu, E-mail: eberger@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-02-20

    Identifying the electromagnetic counterparts of gravitational wave (GW) sources detected by upcoming networks of advanced ground-based interferometers will be challenging, due in part to the large number of unrelated astrophysical transients within the {approx}10-100 deg{sup 2} sky localizations. A potential way to greatly reduce the number of such false positives is to limit detailed follow-up to only those candidates near galaxies within the GW sensitivity range of {approx}200 Mpc for binary neutron star mergers. Such a strategy is currently hindered by the fact that galaxy catalogs are grossly incomplete within this volume. Here, we compare two methods for completing the local galaxy catalog: (1) a narrowband H{alpha} imaging survey and (2) an H I emission line radio survey. Using H{alpha} fluxes, stellar masses (M {sub *}), and star formation rates (SFRs) from galaxies in the Sloan Digital Sky Survey (SDSS), combined with H I data from the GALEX Arecibo SDSS Survey and the Herschel Reference Survey, we estimate that an H{alpha} survey with a luminosity sensitivity of L {sub H{alpha}} = 10{sup 40} erg s{sup -1} at 200 Mpc could achieve a completeness of f {sup H{alpha}} {sub SFR} Almost-Equal-To 75% with respect to total SFR, but only f{sub M* Star-Operator }{sup H{alpha}} approx. 33% with respect to M {sub *} (due to lack of sensitivity to early-type galaxies). These numbers are significantly lower than those achieved by an idealized spectroscopic survey due to the loss of H{alpha} flux resulting from resolving out nearby galaxies and the inability to correct for the underlying stellar continuum. An H I survey with sensitivity similar to the proposed WALLABY survey on ASKAP could achieve f{sub SFR}{sup H{sub I}} Almost-Equal-To 80% and f{sub M Star-Operator }{sup H{sub I}} Almost-Equal-To 50%, somewhat higher than that of the H{alpha} survey. Finally, both H{alpha} and H I surveys should achieve {approx}> 50% completeness with respect to the host galaxies of

  6. Elliptical and lenticular galaxies evolution

    Vigroux, L.

    1981-01-01

    Different evolutionnary models for elliptical and lenticular galaxies are discussed. In the first part, we show that, at least some peculiar early types galaxies exhibit some activity. Then we describe the observationnal constraints: the color-magnitude diagram, the color gradient and the high metallicity of intraclusters gas. Among the different models, only the dissipation collapse followed by a hot wind driven by supernovae explosion explain in a natural way these constraints. Finally, the origin of SO is briefly discussed [fr

  7. SPATIAL ANISOTROPY OF GALAXY KINEMATICS IN SLOAN DIGITAL SKY SURVEY GALAXY CLUSTERS

    Skielboe, Andreas; Wojtak, Radosław; Pedersen, Kristian; Rozo, Eduardo; Rykoff, Eli S.

    2012-01-01

    Measurements of galaxy cluster kinematics are important in understanding the dynamical state and evolution of clusters of galaxies, as well as constraining cosmological models. While it is well established that clusters exhibit non-spherical geometries, evident in the distribution of galaxies on the sky, azimuthal variations of galaxy kinematics within clusters have yet to be observed. Here we measure the azimuthal dependence of the line-of-sight velocity dispersion profile in a stacked sample of 1743 galaxy clusters from the Sloan Digital Sky Survey (SDSS). The clusters are drawn from the SDSS DR8 redMaPPer catalog. We find that the line-of-sight velocity dispersion of galaxies lying along the major axis of the central galaxy is larger than those that lie along the minor axis. This is the first observational detection of anisotropic kinematics of galaxies in clusters. We show that the result is consistent with predictions from numerical simulations. Furthermore, we find that the degree of projected anisotropy is strongly dependent on the line-of-sight orientation of the galaxy cluster, opening new possibilities for assessing systematics in optical cluster finding.

  8. Luminosity-Environment Relation in the Lowz Sample of the SDSS-III

    Deng Xin-Fa

    2016-06-01

    Full Text Available In this work, we examine the environmental dependence of the u-, g-, r-, i- and z-band luminosities in the LOWZ sample of the Sloan Digital Sky Survey Data Release 10 (SDSS DR10. To decrease the radial selection effect, we divide the LOWZ sample into subsamples with a redshift bin size of Δz = 0.01 and analyze the environmental dependence of luminosities for these subsamples in each redshift bin. It is found that all five band luminosities of the LOWZ galaxy sample in the redshift region z=0.16–0.23 show substantial correlation with the local environment, especially in the redshift bins 0.19–0.20 and 0.20–0.21. The environmental dependence of all five band luminosities in the LOWZ galaxy sample becomes weak with increasing redshift, like the one in the apparent-magnitude limited Main galaxy sample.

  9. Searching for modified gravity with baryon oscillations: From SDSS to wide field multiobject spectroscopy (WFMOS)

    Yamamoto, Kazuhiro; Bassett, Bruce A.; Nichol, Robert C.; Suto, Yasushi; Yahata, Kazuhiro

    2006-01-01

    We discuss how the baryon acoustic oscillation (BAO) signatures in the galaxy power spectrum can distinguish between modified gravity and the cosmological constant as the source of cosmic acceleration. To this end we consider a model characterized by a parameter n, which corresponds to the Dvali-Gabadadze-Porrati (DGP) model if n=2 and reduces to the standard spatially flat cosmological constant concordance model for n equal to infinity. We find that the different expansion histories of the modified gravity models systematically shifts the peak positions of BAO. A preliminary analysis using the current SDSS luminous red galaxy (LRG) sample indicates that the original DGP model is disfavored unless the matter density parameter exceeds 0.3. The constraints will be strongly tightened with future spectroscopic samples of galaxies at high redshifts. We demonstrate that WFMOS, in collaboration with other surveys such as Planck, will powerfully constrain modified gravity alternatives to dark energy as the explanation of cosmic acceleration

  10. Spectral evolution of galaxies: current views

    Bruzual, A.G.

    1985-01-01

    A summary of current views on the interpretation of the various evolutionary tests aimed at detecting spectral evolution in galaxies is presented. It is concluded that the evolution taking place in known galaxy samples is a slow process (perhaps consistent with no evolution at all), and that the early phases of rapid spectral evolution in early-type galaxies have not yet been detected. (author)

  11. Supernova rates, galaxy emission, and Hubble type

    Van Den Bergh, S.

    1991-01-01

    Supernova discovery frequency is found to correlate with emission-line (H-alpha + forbidden N II line) equivalent width, except for the most active galaxies in which some supernovae might be hidden by dust. SNII occur preferentially in active galaxies with emission-line EW not less than 20 A, whereas SNIa favor less active galaxies with EW less than 20 A. The intrinsic frequency of supernovae is found to be an order of magnitude higher in Sc galaxies than it is in early type spirals. The relatively high frequency of SNIa in late-type galaxies suggests that not all such objects have old progenitors. 13 refs

  12. Strong chromatic microlensing in HE0047–1756 and SDSS1155+6346

    Rojas, K.; Motta, V. [Instituto de Física y Astronomía, Universidad de Valparaíso, Avda. Gran Bretaña 1111, Playa Ancha, Valparaíso 2360102 (Chile); Mediavilla, E. [Instituto de Astrofísica de Canarias, Avda. Vía Lactea s/n, La Laguna, E-38200 Tenerife (Spain); Falco, E. [Whipple Observatory, Smithsonian Institution, 670 Mt. Hopkins Road, PO Box 6369, Amado, AZ 85645 (United States); Jiménez-Vicente, J. [Departamento de Física Teórica y del Cosmos, Universidad de Granada, Campus de Fuentenueva, E-18071 Granada (Spain); Muñoz, J. A., E-mail: karina.rojas@uv.cl, E-mail: veronica.motta@uv.cl, E-mail: emg@iac.es, E-mail: falco@cfa.harvard.edu, E-mail: jjimenez@ugr.es, E-mail: jmunoz@uv.es [Departamento de Astronomía y Astrofísica, Universidad de Valencia, Burjassot, E-46100 Valencia (Spain)

    2014-12-10

    We use spectra of the double-lensed quasars HE0047–1756 and SDSS1155+6346 to study their unresolved structure through the impact of microlensing. There is no significant evidence of microlensing in the emission line profiles except for the Lyα line of SDSS1155+6346, which shows strong differences in the shapes for images A and B. However, the continuum of the B image spectrum in SDSS1155+6346 is strongly contaminated by the lens galaxy, and these differences should be considered with caution. Using the flux ratios of the emission lines for image pairs as a baseline to remove macro-magnification and extinction, we have detected strong chromatic microlensing in the continuum measured by CASTLES (www.cfa.harvard.edu/castles/) in both lens systems, with amplitudes 0.09(λ16000) ≲ |Δm| ≲ 0.8(λ5439) for HE0047–1756, and 0.2(λ16000) ≲ |Δm| ≲ 0.8(λ5439) for SDSS1155+6346. Using magnification maps to simulate microlensing and modeling the accretion disk as a Gaussian source (I ∝ exp(–R {sup 2}/2r {sub s}{sup 2})) of size r {sub s} ∝ λ {sup p}, we find r {sub s} = 2.5{sub −1.4}{sup +3.0} √(M/0.3M{sub ⊙}) lt-day and p = 2.3 ± 0.8 at the rest frame for λ = 2045 for HE0047–1756 (log prior) and r {sub s} = 5.5{sub −3.3}{sup +8.2} √(M/0.3M{sub ⊙}) lt-day and p = 1.5 ± 0.6 at the rest frame of λ = 1398 for SDSS1155+6346 (log prior). Contrary to other studied lens systems, the chromaticity detected in HE0047–1756 and SDSS1155+6346 is large enough to fulfill the thin disk prediction. The inferred sizes, however, are very large compared to the predictions of this model, especially in the case of SDSS1155+6346.

  13. A direct measurement of the baryonic mass function of galaxies & implications for the galactic baryon fraction

    Papastergis, Emmanouil; Cattaneo, Andrea; Huang, Shan; Giovanelli, Riccardo; Haynes, Martha P.

    2012-01-01

    We use both an HI-selected and an optically-selected galaxy sample to directly measure the abundance of galaxies as a function of their "baryonic" mass (stars + atomic gas). Stellar masses are calculated based on optical data from the Sloan Digital Sky Survey (SDSS) and atomic gas masses are

  14. THE METALLICITIES OF LOW STELLAR MASS GALAXIES AND THE SCATTER IN THE MASS-METALLICITY RELATION

    Zahid, H. J.; Bresolin, F.; Kewley, L. J.; Coil, A. L.; Davé, R.

    2012-01-01

    In this investigation, we quantify the metallicities of low-mass galaxies by constructing the most comprehensive census to date. We use galaxies from the Sloan Digital Sky Survey (SDSS) and DEEP2 survey and estimate metallicities from their optical emission lines. We also use two smaller samples from the literature that have metallicities determined by the direct method using the temperature sensitive [O III]λ4363 line. We examine the scatter in the local mass-metallicity (MZ) relation determined from ∼20,000 star-forming galaxies in the SDSS and show that it is larger at lower stellar masses, consistent with the theoretical scatter in the MZ relation determined from hydrodynamical simulations. We determine a lower limit for the scatter in metallicities of galaxies down to stellar masses of ∼10 7 M ☉ which is only slightly smaller than the expected scatter inferred from the SDSS MZ relation and significantly larger than what has been previously established in the literature. The average metallicity of star-forming galaxies increases with stellar mass. By examining the scatter in the SDSS MZ relation, we show that this is mostly due to the lowest metallicity galaxies. The population of low-mass, metal-rich galaxies have properties that are consistent with previously identified galaxies that may be transitional objects between gas-rich dwarf irregulars and gas-poor dwarf spheroidals and ellipticals.

  15. The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey

    Ahn, Christopher P.; Alexandroff, Rachael; Allende Prieto, Carlos; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Aubourg, Éric; Bailey, Stephen; Balbinot, Eduardo; Barnes, Rory; Bautista, Julian; Beers, Timothy C.; Beifiori, Alessandra; Berlind, Andreas A.; Bhardwaj, Vaishali; Bizyaev, Dmitry; Blake, Cullen H.; Blanton, Michael R.; Blomqvist, Michael; Bochanski, John J.; Bolton, Adam S.; Borde, Arnaud; Bovy, Jo; Brandt, W. N.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Bundy, Kevin; Busca, N. G.; Carithers, William; Carnero, Aurelio R.; Carr, Michael A.; Casetti-Dinescu, Dana I.; Chen, Yanmei; Chiappini, Cristina; Comparat, Johan; Connolly, Natalia; Crepp, Justin R.; Cristiani, Stefano; Croft, Rupert A. C.; Cuesta, Antonio J.; da Costa, Luiz N.; Davenport, James R. A.; Dawson, Kyle S.; de Putter, Roland; De Lee, Nathan; Delubac, Timothée; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Escoffier, S.; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Femenía Castellá, Bruno; Fernández Alvar, Emma; Ferreira, Leticia D.; Filiz Ak, N.; Finley, Hayley; Fleming, Scott W.; Font-Ribera, Andreu; Frinchaboy, Peter M.; García-Hernández, D. A.; Pérez, A. E. García; Ge, Jian; Génova-Santos, R.; Gillespie, Bruce A.; Girardi, Léo; González Hernández, Jonay I.; Grebel, Eva K.; Gunn, James E.; Guo, Hong; Haggard, Daryl; Hamilton, Jean-Christophe; Harris, David W.; Hawley, Suzanne L.; Hearty, Frederick R.; Ho, Shirley; Hogg, David W.; Holtzman, Jon A.; Honscheid,