WorldWideScience

Sample records for high-redshift protogalaxy canidates

  1. Radio-loud high-redshift protogalaxy canidates in Bootes

    Energy Technology Data Exchange (ETDEWEB)

    Croft, S; van Breugel, W; Brown, M J; de Vries, W; Dey, A; Eisenhardt, P; Jannuzi, B; Rottgering, H; Stanford, S A; Stern, D; Willner, S P

    2007-07-20

    We used the Near Infrared Camera (NIRC) on Keck I to obtain K{sub s}-band images of four candidate high-redshift radio galaxies selected using optical and radio data in the NOAO Deep Wide-Field Survey in Bootes. Our targets have 1.4 GHz radio flux densities greater than 1 mJy, but are undetected in the optical. Spectral energy distribution fitting suggests that three of these objects are at z > 3, with radio luminosities near the FR-I/FR-II break. The other has photometric redshift z{sub phot} = 1.2, but may in fact be at higher redshift. Two of the four objects exhibit diffuse morphologies in K{sub s}-band, suggesting that they are still in the process of forming.

  2. High Redshift GRBs

    Science.gov (United States)

    Gehrels, Neil; Cannizzo, John K.

    2012-01-01

    The Swift mission has opened a new, high redshift window on the universe. In this review we provide an overview of gamma-ray burst (GRB) science, describe the Swift mission, discuss high-z GRBs and tools for high-z studies, and look forward at future capabilities. A new mission concept - Lobster - is described that would monitor the X-ray sky at order of magnitude higher sensitivity than current missions.

  3. High-redshift cosmography

    Science.gov (United States)

    Vitagliano, Vincenzo; Xia, Jun-Qing; Liberati, Stefano; Viel, Matteo

    2010-03-01

    We constrain the parameters describing the kinematical state of the universe using a cosmographic approach, which is fundamental in that it requires a very minimal set of assumptions (namely to specify a metric) and does not rely on the dynamical equations for gravity. On the data side, we consider the most recent compilations of Supernovae and Gamma Ray Bursts catalogues. This allows to further extend the cosmographic fit up to z = 6.6, i.e. up to redshift for which one could start to resolve the low z degeneracy among competing cosmological models. In order to reliably control the cosmographic approach at high redshifts, we adopt the expansion in the improved parameter y = z/(1+z). This series has the great advantage to hold also for z > 1 and hence it is the appropriate tool for handling data including non-nearby distance indicators. We find that Gamma Ray Bursts, probing higher redshifts than Supernovae, have constraining power and do require (and statistically allow) a cosmographic expansion at higher order than Supernovae alone. Exploiting the set of data from Union and GRBs catalogues, we show (for the first time in a purely cosmographic approach parametrized by deceleration q0, jerk j0, snap s0) a definitively negative deceleration parameter q0 up to the 3σ confidence level. We present also forecasts for realistic data sets that are likely to be obtained in the next few years.

  4. High-redshift cosmography

    Energy Technology Data Exchange (ETDEWEB)

    Vitagliano, Vincenzo; Xia, Jun-Qing; Liberati, Stefano [SISSA, Via Beirut 2-4, 34151 Trieste (Italy); Viel, Matteo, E-mail: vitaglia@sissa.it, E-mail: xia@sissa.it, E-mail: liberati@sissa.it, E-mail: viel@oats.inaf.it [INFN sez. Trieste, Via Valerio 2, 34127 Trieste (Italy)

    2010-03-01

    We constrain the parameters describing the kinematical state of the universe using a cosmographic approach, which is fundamental in that it requires a very minimal set of assumptions (namely to specify a metric) and does not rely on the dynamical equations for gravity. On the data side, we consider the most recent compilations of Supernovae and Gamma Ray Bursts catalogues. This allows to further extend the cosmographic fit up to z = 6.6, i.e. up to redshift for which one could start to resolve the low z degeneracy among competing cosmological models. In order to reliably control the cosmographic approach at high redshifts, we adopt the expansion in the improved parameter y = z/(1+z). This series has the great advantage to hold also for z > 1 and hence it is the appropriate tool for handling data including non-nearby distance indicators. We find that Gamma Ray Bursts, probing higher redshifts than Supernovae, have constraining power and do require (and statistically allow) a cosmographic expansion at higher order than Supernovae alone. Exploiting the set of data from Union and GRBs catalogues, we show (for the first time in a purely cosmographic approach parametrized by deceleration q{sub 0}, jerk j{sub 0}, snap s{sub 0}) a definitively negative deceleration parameter q{sub 0} up to the 3σ confidence level. We present also forecasts for realistic data sets that are likely to be obtained in the next few years.

  5. Galaxies at High Redshift

    Science.gov (United States)

    Bauer, F. E.

    2014-10-01

    Recent years have seen tremendous progress in finding and charactering star-forming galaxies at high redshifts across the electromagnetic spectrum, giving us a more complete picture of how galaxies evolve, both in terms of their stellar and gas content, as well as the growth of their central supermassive black holes. A wealth of studies now demonstrate that star formation peaked at roughly half the age of the Universe and drops precariously as we look back to very early times, and that their central monsters apparently growth with them. At the highest-redshifts, we are pushing the boundaries via deep surveys at optical, X-ray, radio wavelengths, and more recently using gamma-ray bursts. I will review some of our accomplishments and failures. Telescope have enabled Lyman break galaxies to be robustly identified, but the UV luminosity function and star formation rate density of this population at z = 6 - 8 seems to be much lower than at z = 2 - 4. High escape fractions and a large contribution from faint galaxies below our current detection limits would be required for star-forming galaxies to reionize the Universe. We have also found that these galaxies have blue rest-frame UV colours, which might indicate lower dust extinction at z > 5. There has been some spectroscopic confirmation of these Lyman break galaxies through Lyman-α emission, but the fraction of galaxies where we see this line drops at z > 7, perhaps due to the onset of the Gunn-Peterson effect (where the IGM is opaque to Lyman-α).

  6. Magnetized Turbulent Dynamo in Protogalaxies

    Energy Technology Data Exchange (ETDEWEB)

    Leonid Malyshkin; Russell M. Kulsrud

    2002-01-28

    The prevailing theory for the origin of cosmic magnetic fields is that they have been amplified to their present values by the turbulent dynamo inductive action in the protogalactic and galactic medium. Up to now, in calculation of the turbulent dynamo, it has been customary to assume that there is no back reaction of the magnetic field on the turbulence, as long as the magnetic energy is less than the turbulent kinetic energy. This assumption leads to the kinematic dynamo theory. However, the applicability of this theory to protogalaxies is rather limited. The reason is that in protogalaxies the temperature is very high, and the viscosity is dominated by magnetized ions. As the magnetic field strength grows in time, the ion cyclotron time becomes shorter than the ion collision time, and the plasma becomes strongly magnetized. As a result, the ion viscosity becomes the Braginskii viscosity. Thus, in protogalaxies the back reaction sets in much earlier, at field strengths much lower than those which correspond to field-turbulence energy equipartition, and the turbulent dynamo becomes what we call the magnetized turbulent dynamo. In this paper we lay the theoretical groundwork for the magnetized turbulent dynamo. In particular, we predict that the magnetic energy growth rate in the magnetized dynamo theory is up to ten times larger than that in the kinematic dynamo theory. We also briefly discuss how the Braginskii viscosity can aid the development of the inverse cascade of magnetic energy after the energy equipartition is reached.

  7. The implications of dust for high-redshift protogalaxies and the formation of binary disks

    OpenAIRE

    Latif, M. A.; Schleicher, D. R. G.; Spaans, M.

    2012-01-01

    Numerical simulations suggest that the first galaxies are formed in protogalactic halos with virial temperatures ≥104 K. It is likely that such halos are polluted with trace amounts of metals produced by the first generation of stars. The presence of dust can significantly change the chemistry and dynamics of early galaxies. In this article, we aim to assess the role of dust on the thermal and dynamical evolution of the first galaxies in the presence of a background UV flux, and its ...

  8. Accurate Emission Line Diagnostics at High Redshift

    Science.gov (United States)

    Jones, Tucker

    2017-08-01

    How do the physical conditions of high redshift galaxies differ from those seen locally? Spectroscopic surveys have invested hundreds of nights of 8- and 10-meter telescope time as well as hundreds of Hubble orbits to study evolution in the galaxy population at redshifts z 0.5-4 using rest-frame optical strong emission line diagnostics. These surveys reveal evolution in the gas excitation with redshift but the physical cause is not yet understood. Consequently there are large systematic errors in derived quantities such as metallicity.We have used direct measurements of gas density, temperature, and metallicity in a unique sample at z=0.8 to determine reliable diagnostics for high redshift galaxies. Our measurements suggest that offsets in emission line ratios at high redshift are primarily caused by high N/O abundance ratios. However, our ground-based data cannot rule out other interpretations. Spatially resolved Hubble grism spectra are needed to distinguish between the remaining plausible causes such as active nuclei, shocks, diffuse ionized gas emission, and HII regions with escaping ionizing flux. Identifying the physical origin of evolving excitation will allow us to build the necessary foundation for accurate measurements of metallicity and other properties of high redshift galaxies. Only then can we expoit the wealth of data from current surveys and near-future JWST spectroscopy to understand how galaxies evolve over time.

  9. The high redshift universe and cosmology

    Science.gov (United States)

    Hook, Isobel

    2013-12-01

    The ELTs, assisted by adaptive optics, will revolutionise observations of the high redshift universe. Using examples taken primarily from the science case of the E-ELT, this talk will cover prospects and requirements for studying distant galaxies and point sources at cosmological distances including gamma ray bursts, quasars and supernovae. The impact these observations will have on cosmology and our understanding of the early universe will be discussed.

  10. Observations of GRBs at high redshift.

    Science.gov (United States)

    Tanvir, Nial R; Jakobsson, Páll

    2007-05-15

    The extreme luminosity of gamma-ray bursts and their afterglows means they are detectable, in principle, to very high redshifts. Although the redshift distribution of gamma-ray bursts (GRBs) is difficult to determine, due to incompleteness of present samples, we argue that for Swift-detected bursts, the median redshift is between 2.5 and 3, with a few per cent probably at z>6. Thus, GRBs are potentially powerful probes of the era of reionization and the sources responsible for it. Moreover, it seems probable that they can provide constraints on the star-formation history of the Universe and may also help in the determination of the cosmological parameters.

  11. Quasar Elemental Abundances at High Redshifts

    DEFF Research Database (Denmark)

    Dietrich, M.; Hamann, F.; Shields, J. C.

    2003-01-01

    We examine rest-frame ultraviolet spectra of 70 high redshift quasars (z>3.5) to study the chemical enrichment history of the gas closely related to the quasars, and thereby estimate the epoch of first star formation. The fluxes of several ultraviolet emission lines were investigated within...... scale of t_evol = 0.5 - 0.8 Gyrs for the chemical enrichment of the gas, the first major star formation for quasars with z>=4 should have started at a redshift of z_f = 6 - 8, corresponding to an age of the universe of several 10^8 yrs (H_o = 65 km/s/Mpc, Omega_M = 0.3, Omega_Lambda = 0.7). We note...

  12. Galaxy luminosity function: evolution at high redshift

    Science.gov (United States)

    Martinet, N.; Durret, F.; Guennou, L.; Adami, C.

    2014-12-01

    There are some disagreements about the abundance of faint galaxies in high redshift clusters. DAFT/FADA (Dark energy American French Team) is a medium redshift (0.4

  13. Highly Accreting Quasars at High Redshift

    Directory of Open Access Journals (Sweden)

    Mary L. Martínez-Aldama

    2018-01-01

    Full Text Available We present preliminary results of a spectroscopic analysis for a sample of type 1 highly accreting quasars (L/LEdd ~ 1.0 at high redshift, z ~2–3. The quasars were observed with the OSIRIS spectrograph on the GTC 10.4 m telescope located at the Observatorio del Roque de los Muchachos in La Palma. The highly accreting quasars were identified using the 4D Eigenvector 1 formalism, which is able to organize type 1 quasars over a broad range of redshift and luminosity. The kinematic and physical properties of the broad line region have been derived by fitting the profiles of strong UV emission lines such as Aliiiλ1860, Siiii]λ1892 and Ciii]λ1909. The majority of our sources show strong blueshifts in the high-ionization lines and high Eddington ratios which are related with the productions of outflows. The importance of highly accreting quasars goes beyond a detailed understanding of their physics: their extreme Eddington ratio makes them candidates standard candles for cosmological studies.

  14. Search for High Redshift Galaxy Clusters

    Science.gov (United States)

    Haarsma, D. B.; Butler, A. R.; Donahue, M. E.; Bruch, S. S.

    2005-12-01

    Distant galaxy clusters are key to understanding many current questions in cosmology, structure formation, and galaxy evolution, yet few z>1 clusters have been identified. The ROSAT Optical X-ray Survey (Donahue et al. 2002 ApJ 569, 689) searched for galaxy clusters using both optical and x-ray detection methods. While many clusters appeared in both wavebands, 10 targets which showed extended x-ray emission (a unique signature of cluster gas) did not show significant I-band emission (expected from elliptical galaxies in the cluster). These targets may be galaxy clusters with redshift greater than 1, which would appear faint in I due to the 400 nm break in elliptical galaxy spectra. In J and K bands, such galaxies would be easier to detect, and in April 2005 we imaged the 10 fields in J and K with the FLAMINGOS camera on the NOAO 4m telescope. The infrared colors are useful in identifying clusters, because all elliptical galaxies in a cluster are expected to have similar colors (i.e. the red sequence). We report preliminary identifications of high redshift galaxy clusters in our sample.

  15. A High Redshift Survey of Lyman Limit Systems

    Science.gov (United States)

    Beltz, Hayley; Jorgenson, Regina A.; Rafelski, Marc

    2018-01-01

    Lyman Limit Systems (LLSs), a class of quasar absorption line system detected towards background quasars, are ubiquitous in quasar spectra and provide a crucial tool for understanding high redshift galaxy formation and evolution. At moderate neutral hydrogen (HI) column densities, 1017.5complement to these previous studies, we present a survey of LLSs in a sample of twenty-six, high redshift (z>5) quasars with VLT/X-Shooter spectra. These high redshift systems unlock information about the universe during its first few gigayears. We calculate the number of systems per unit redshift, l(X), at z >4.4, extending the redshift evolution of LLSs presented in Fumagalli et al. (2015). For those systems with associated metal line absorption, we provide an estimate of the LLSs metallicity. This project was supported in part by the NSF REU grant AST-1358980 and by the Nantucket Maria Mitchell Association.

  16. Probing the bias of radio sources at high redshift

    CSIR Research Space (South Africa)

    Passmoor, S

    2012-11-01

    Full Text Available The relationship between the clustering of dark matter and that of luminous matter is often described using the bias parameter. Here, we provide a new method to probe the bias of intermediate-to-high-redshift radio continuum sources for which...

  17. The intergalactic medium near high-redshift galaxies

    NARCIS (Netherlands)

    Rakic, Olivera

    2012-01-01

    Over the past 15 years, the field of extragalactic astronomy has pushed to high redshift and our knowledge of natal galaxies has grown dramatically. Galaxies are now routinely detected at redshifts z ! 6−7 (e.g. Bouwens et al. 2010; Labb´e et al. 2010; Oesch et al. 2010; Bouwens et al. 2011;

  18. Discerning dark energy models with high redshift standard candles

    Science.gov (United States)

    Andersen, P.; Hjorth, J.

    2017-12-01

    Following the success of type Ia supernovae in constraining cosmologies at lower redshift (z ≲ 2), effort has been spent determining if a similarly useful standardizable candle can be found at higher redshift. In this work, we determine the largest possible magnitude discrepancy between a constant dark energy ΛCDM cosmology and a cosmology in which the equation of state w(z) of dark energy is a function of redshift for high redshift standard candles (z ≳ 2). We discuss a number of popular parametrizations of w(z) with two free parameters, wzCDM cosmologies, including the Chevallier-Polarski-Linder and generalization thereof, nCPL, as well as the Jassal-Bagla-Padmanabhan parametrization. For each of these parametrizations, we calculate and find the extrema of Δμ, the difference between the distance modulus of a wzCDM cosmology and a fiducial ΛCDM cosmology as a function of redshift, given 68 per cent likelihood constraints on the parameters P = (Ωm, 0, w0, wa). The parameters are constrained using cosmic microwave background, baryon acoustic oscillations and type Ia supernovae data using CosmoMC. We find that none of the tested cosmologies can deviate more than 0.05 mag from the fiducial ΛCDM cosmology at high redshift, implying that high redshift standard candles will not aid in discerning between the wzCDM cosmology and the fiducial ΛCDM cosmology. Conversely, this implies that if high redshift standard candles are found to be in disagreement with ΛCDM at high redshift, then this is a problem not only for ΛCDM but for the entire family of wzCDM cosmologies.

  19. High-Redshift galaxies light from the early universe

    CERN Document Server

    Appenzeller, Immo

    2008-01-01

    This book provides a comprehensive account of the scientific results on high-redshift galaxies accumulated during the past ten years. Apart from summarizing and critically discussing the wealth of observational data, the observational methods which made it possible to study these very distant and extremely faint objects are described in detail. Moreover, the technical feasibilities and physical limitations for existing and for future ground-based and space-based telescopes are discussed. Thus, apart from summarizing the knowledge accumulated so far, the book is designed as a tool for planning future observational and instrumental programs and projects. In view of the potential importance of the observational results of the high-redshift universe for basic physics the book is written for astronomers as well as for physicists without prior astronomical knowledge. For this purpose it contains introductory chapters describing the basic concepts and notations used in modern astronomy and a brief overview of the pr...

  20. Detectability of Gravitational Waves from High-Redshift Binaries.

    Science.gov (United States)

    Rosado, Pablo A; Lasky, Paul D; Thrane, Eric; Zhu, Xingjiang; Mandel, Ilya; Sesana, Alberto

    2016-03-11

    Recent nondetection of gravitational-wave backgrounds from pulsar timing arrays casts further uncertainty on the evolution of supermassive black hole binaries. We study the capabilities of current gravitational-wave observatories to detect individual binaries and demonstrate that, contrary to conventional wisdom, some are, in principle, detectable throughout the Universe. In particular, a binary with rest-frame mass ≳10^{10}M_{⊙} can be detected by current timing arrays at arbitrarily high redshifts. The same claim will apply for less massive binaries with more sensitive future arrays. As a consequence, future searches for nanohertz gravitational waves could be expanded to target evolving high-redshift binaries. We calculate the maximum distance at which binaries can be observed with pulsar timing arrays and other detectors, properly accounting for redshift and using realistic binary waveforms.

  1. Photometry of High-Redshift Gravitationally Lensed Type Ia Supernovae

    Science.gov (United States)

    Haynie, Annastasia

    2018-01-01

    Out of more than 1100 well-identified Type Ia Supernovae, only roughly 10 of them are at z> 1.5. High redshift supernovae are hard to detect but this is made easier by taking advantage of the effects of gravitational lensing, which magnifies objects in the background field of massive galaxy clusters. Supernova Nebra (z= ~1.8), among others, was discovered during observations taken as part of the RELICS survey, which focused on fields of view that experience strong gravitational lensing effects. SN Nebra, which sits behind galaxy cluster Abell 1763, is magnified and therefore appears closer and easier to see than with HST alone. Studying high-redshift supernovae like SN Nebra is an important step towards creating cosmological models that accurately describe the behavior of dark energy in the early Universe. Recent efforts have been focused on improving photometry and the building and fitting of preliminary light curves.

  2. The high redshift Integrated Sachs-Wolfe effect

    Science.gov (United States)

    Xia, Jun-Qing; Viel, Matteo; Baccigalupi, Carlo; Matarrese, Sabino

    2009-09-01

    In this paper we rely on the quasar (QSO) catalog of the Sloan Digital Sky Survey Data Release Six (SDSS DR6) of about one million photometrically selected QSOs to compute the Integrated Sachs-Wolfe (ISW) effect at high redshift, aiming at constraining the behavior of the expansion rate and thus the behaviour of dark energy at those epochs. This unique sample significantly extends previous catalogs to higher redshifts while retaining high efficiency in the selection algorithm. We compute the auto-correlation function (ACF) of QSO number density from which we extract the bias and the stellar contamination. We then calculate the cross-correlation function (CCF) between QSO number density and Cosmic Microwave Background (CMB) temperature fluctuations in different subsamples: at high z > 1.5 and low z analysis. We find an overall evidence for a cross-correlation different from zero at the 2.7 σ level, while this evidence drops to 1.5 σ at z > 1.5. We focus on the capabilities of the ISW to constrain the behaviour of the dark energy component at high redshift both in the Λ CDM and Early Dark Energy cosmologies, when the dark energy is substantially unconstrained by observations. At present, the inclusion of the ISW data results in a poor improvement compared to the obtained constraints from other cosmological datasets. We study the capabilities of future high-redshift QSO survey and find that the ISW signal can improve the constraints on the most important cosmological parameters derived from Planck CMB data, including the high redshift dark energy abundance, by a factor ~ 1.5.

  3. High-redshift SDSS Quasars with Weak Emission Lines

    DEFF Research Database (Denmark)

    Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Brandt, W. N.

    2009-01-01

    We identify a sample of 74 high-redshift quasars (z > 3) with weak emission lines from the Fifth Data Release of the Sloan Digital Sky Survey and present infrared, optical, and radio observations of a subsample of four objects at z > 4. These weak emission-line quasars (WLQs) constitute a prominent...... rest-frame 0.1-5 µm spectral energy distributions that are quite similar to those of normal quasars. The variability, polarization, and radio properties of WLQs are also different from those of BL Lacs, making continuum boosting by a relativistic jet an unlikely physical interpretation. The most...

  4. Short-term optical variability of high-redshift QSO's

    OpenAIRE

    Bachev, R.; Strigachev, A.; Semkov, E.

    2004-01-01

    This paper presents results of a search for short-term variability in the optical band of selected high-luminosity, high-redshift radio-quiet quasars. Each quasar has been monitored typically for 2 - 4 hours with a time resolution of 2 - 5 minutes and a photometric accuracy of about 0.01 - 0.02 mag. Due to the significant redshift (z>2), the covered wavelength range falls into the UV region (typically 1500 - 2500A). We found no statistical evidence for any continuum variations larger than 0.0...

  5. Radiative Feedback in the Formation of the First Protogalaxies

    Science.gov (United States)

    Johnson, Jarrett L.; Greif, T. H.; Bromm, V.

    2007-12-01

    The first galaxies form under the influence of radiative feedback from the first generations of stars. This feedback acts to heat and ionize the gas within the H II regions surrounding the first stars, as well as to photodissociate hydrogen molecules within the larger Lyman-Werner (LW) bubbles that surround these sources. Using a ray-tracing method in three-dimensional cosmological simulations, we self-consistently track the formation of, and radiative feedback from, individual stars in the formation of a protogalaxy. We compute in detail the H II regions of each of these sources, as well as the regions affected by their molecule-dissociating radiation. We follow the thermal, chemical, and dynamical evolution of the primordial gas as it becomes incorporated into the protogalaxy. While the IGM is, in general, optically thick to LW photons only over physical distances of > 30 kpc at redshifts zfactor renders even the local IGM optically thick to LW photons over physical distances of a few kiloparsecs. We find that Population III relic black holes may begin accreting efficiently after 60 Myr from the time of their formation, when the photo-heated relic H II region gas can cool and recollapse into the 106 Msolar minihalo which hosts the black hole. Metal-free Population II.5 stars, postulated to have masses of the order of 10 Msolar, can also likely form from this recollapsing relic H II region gas. Overall, we find that the local radiative feedback from Population III stars suppresses the star formation rate only slightly.

  6. Local Radiative Feedback in the Formation of the First Protogalaxies

    Science.gov (United States)

    Johnson, Jarrett L.; Greif, Thomas H.; Bromm, Volker

    2007-08-01

    The first galaxies form under the influence of radiative feedback from the first generations of stars. This feedback acts to heat and ionize the gas within the H II regions surrounding the first stars, as well as to photodissociate hydrogen molecules within the larger Lyman-Werner (LW) bubbles that surround these sources. Using a ray-tracing method in three-dimensional cosmological simulations, we self-consistently track the formation of, and radiative feedback from, individual stars in the formation of a protogalaxy. We compute in detail the H II regions of each of these sources, as well as the regions affected by their molecule-dissociating radiation. We follow the thermal, chemical, and dynamical evolution of the primordial gas as it becomes incorporated into the protogalaxy. While the IGM is, in general, optically thick to LW photons only over physical distances of >~30 kpc at redshifts zfactor renders even the local IGM optically thick to LW photons over physical distances of a few kiloparsecs. We find that Population III relic black holes may begin accreting efficiently after ~60 Myr from the time of their formation, when the photo-heated relic H II region gas can cool and recollapse into the 106 Msolar minihalo which hosts the black hole. Population II.5 stars, postulated to have masses of the order of 10 Msolar, can also likely form from this recollapsing relic H II region gas. Overall, we find that the local radiative feedback from Population III stars suppresses the star formation rate only slightly.

  7. Estimating Luminosity Function Constraints from High-Redshift Galaxy Surveys

    Science.gov (United States)

    Robertson, Brant E.

    2010-04-01

    The installation of the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) will revolutionize the study of high-redshift galaxy populations. Initial observations of the HST Ultra Deep Field (UDF) have yielded multiple z >~ 7 dropout candidates. Supplemented by the GOODS Early Release Science (ERS) and further UDF pointings, these data will provide crucial information about the most distant known galaxies. However, achieving tight constraints on the z ~ 7 galaxy luminosity function (LF) will require even more ambitious photometric surveys. Using a Fisher matrix approach to fully account for Poisson and cosmic sample variance, as well as covariances in the data, we estimate the uncertainties on LF parameters achieved by surveys of a given area and depth. Applying this method to WFC3 z ~ 7 dropout galaxy samples, we forecast the LF parameter uncertainties for a variety of model surveys. We demonstrate that performing a wide area (~1 deg2) survey to H AB ~ 27 depth or increasing the UDF depth to H AB ~ 30 provides excellent constraints on the high-z LF when combined with the existing Ultradeep Field Guest Observation and GOODS ERS data. We also show that the shape of the matter power spectrum may limit the possible gain of splitting wide area (gsim0.5 deg2) high-redshift surveys into multiple fields to probe statistically independent regions; the increased rms density fluctuations in smaller volumes mostly offset the improved variance gained from independent samples.

  8. Dark matter annihilation in the circumgalactic medium at high redshifts

    Science.gov (United States)

    Schön, S.; Mack, K. J.; Wyithe, J. S. B.

    2018-03-01

    Annihilating dark matter (DM) models offer promising avenues for future DM detection, in particular via modification of astrophysical signals. However, when modelling such potential signals at high redshift, the emergence of both DM and baryonic structure, as well as the complexities of the energy transfer process, needs to be taken into account. In the following paper, we present a detailed energy deposition code and use this to examine the energy transfer efficiency of annihilating DM at high redshift, including the effects on baryonic structure. We employ the PYTHIA code to model neutralino-like DM candidates and their subsequent annihilation products for a range of masses and annihilation channels. We also compare different density profiles and mass-concentration relations for 105-107 M⊙ haloes at redshifts 20 and 40. For these DM halo and particle models, we show radially dependent ionization and heating curves and compare the deposited energy to the haloes' gravitational binding energy. We use the `filtered' annihilation spectra escaping the halo to calculate the heating of the circumgalactic medium and show that the mass of the minimal star-forming object is increased by a factor of 2-3 at redshift 20 and 4-5 at redshift 40 for some DM models.

  9. Probing the Circumgalactic Gas around High Redshift Galaxies with VUDS

    Science.gov (United States)

    Méndez-Hernández, Hugo; Cassata, Paolo; Ibar, Eduardo

    2017-07-01

    We probe the CGM of high redshift galaxies belonging to VIMOS Ultra Deep Survey. We used deep spectroscopy of different lines-of-sight around foreground galaxies to get useful information on the overall kinematics, chemical abundances, and (in some cases) estimates of the mass flux of cool material entrained in an in-outflow.We have selected a sample of 1244 close (0 150 kpc) galaxy pairs from the Vimos Ultra-Deep Survey (VUDS) to probe the circumgalactic medium (CGM) around galaxies at 2CIV, OISiII, CIV, AlII) out to galactocentric radii of ˜150 kpc on stacked spectra, and found that the CGM of galaxies at 2< z <5 are rich in metals even at ˜150 kpc away from the galaxies.

  10. Close companions to two high-redshift quasars

    Energy Technology Data Exchange (ETDEWEB)

    McGreer, Ian D.; Fan, Xiaohui; Bian, Fuyan [Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Strauss, Michael A. [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States); Haiman, Zoltàn [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Richards, Gordon T. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Jiang, Linhua [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Schneider, Donald P., E-mail: imcgreer@as.arizona.edu [Department of Astronomy and Astrophysics and the Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802 (United States)

    2014-10-01

    We report the serendipitous discoveries of companion galaxies to two high-redshift quasars. SDSS J025617.7+001904 is a z = 4.79 quasar included in our recent survey of faint quasars in the SDSS Stripe 82 region. The initial MMT slit spectroscopy shows excess Lyα emission extending well beyond the quasar's light profile. Further imaging and spectroscopy with LBT/MODS1 confirms the presence of a bright galaxy (i {sub AB} = 23.6) located 2'' (12 kpc projected) from the quasar with strong Lyα emission (EW{sub 0} ≈ 100 Å) at the redshift of the quasar, as well as faint continuum. The second quasar, CFHQS J005006.6+344522 (z = 6.25), is included in our recent HST SNAP survey of z ∼ 6 quasars searching for evidence of gravitational lensing. Deep imaging with ACS and WFC3 confirms an optical dropout ∼4.5 mag fainter than the quasar (Y {sub AB} = 25) at a separation of 0.''9. The red i {sub 775} – Y {sub 105} color of the galaxy and its proximity to the quasar (5 kpc projected if at the quasar redshift) strongly favor an association with the quasar. Although it is much fainter than the quasar, it is remarkably bright when compared to field galaxies at this redshift, while showing no evidence for lensing. Both systems may represent late-stage mergers of two massive galaxies, with the observed light for one dominated by powerful ongoing star formation and for the other by rapid black hole growth. Observations of close companions are rare; if major mergers are primarily responsible for high-redshift quasar fueling then the phase when progenitor galaxies can be observed as bright companions is relatively short.

  11. X-RAY ABSORPTION OF HIGH-REDSHIFT QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Eitan, Assaf; Behar, Ehud, E-mail: sassafe@tx.technion.ac.il, E-mail: behar@physics.technion.ac.il [Physics Department, Technion, Haifa 32000 (Israel)

    2013-09-01

    The soft X-ray photoelectric absorption of high-z quasars has been known for two decades, but has no unambiguous astrophysical context. We construct the largest sample to date of 58 high-redshift quasars (z > 0.45) selected from the XMM-Newton archive based on a high photon count criterion (>1800). We measure the optical depth {tau} at 0.5 keV and find that 43% of the quasars show significant absorption. We aim to find which physical parameters of the quasars, e.g., redshift, radio luminosity, radio loudness, or X-ray luminosity, drive their observed absorption. We compare the absorption behavior with redshift with the pattern expected if the diffuse intergalactic medium (IGM) is responsible for the observed absorption. We also compare the absorption with a comparison sample of gamma-ray burst (GRB) X-ray afterglows. Although the z > 2 quasar opacity is consistent with diffuse IGM absorption, many intermediate-z (0.45 < z < 2) quasars are not sufficiently absorbed for this scenario, and are appreciably less absorbed than GRBs. Only 10/37 quasars at z < 2 are absorbed, and only 5/30 radio-quiet quasars are absorbed. We find a weak correlation between {tau} and z, and an even weaker correlation between {tau} and radio luminosity. These findings lead to the conclusion that although a diffuse IGM origin for the quasar absorption is unlikely, the optical depth does seem to increase with redshift, roughly as (1 + z){sup 2.2{+-}0.6}, tending to {tau} Almost-Equal-To 0.4 at high redshifts, similar to the high-z GRBs. This result can be explained by an ionized and clumpy IGM at z < 2, and a cold, diffuse IGM at higher redshift. If, conversely, the absorption occurs at the quasar, and owing to the steep L{sub x} {proportional_to}(1 + z){sup 7.1{+-}0.5} correlation in the present sample, the host column density scales as N{sub H}{proportional_to}L{sub x}{sup 0.7{+-}0.1}.

  12. Tracing a high redshift cosmic web with quasar systems

    Science.gov (United States)

    Einasto, Maret; Tago, Erik; Lietzen, Heidi; Park, Changbom; Heinämäki, Pekka; Saar, Enn; Song, Hyunmi; Liivamägi, Lauri Juhan; Einasto, Jaan

    2014-08-01

    Context. To understand the formation, evolution, and present-day properties of the cosmic web we need to study it at low and high redshifts. Aims: We trace the cosmic web at redshifts that range from 1.0 ≤ z ≤ 1.8 by using the quasar (QSO) data from the SDSS DR7 QSO catalogue. Methods: We apply a friend-of-friend algorithm to the quasar and random catalogues to determine systems at a series of linking length and analyse richness and sizes of these systems. Results: At the linking lengths l ≤ 30 h-1 Mpc, the number of quasar systems is larger than the number of systems detected in random catalogues, and the systems themselves have smaller diameters than random systems. The diameters of quasar systems are comparable to the sizes of poor galaxy superclusters in the local Universe. The richest quasar systems have four members. The mean space density of quasar systems, ≈ 10-7 (h-1 Mpc)-3, is close to the mean space density of local rich superclusters. At intermediate linking lengths (40 ≤ l ≤ 70 h-1 Mpc), the richness and length of quasar systems are similar to those derived from random catalogues. Quasar system diameters are similar to the sizes of rich superclusters and supercluster chains in the local Universe. The percolating system, which penetrate the whole sample volume appears in a quasar sample at a smaller linking length than in random samples (85 h-1 Mpc). At the linking length 70 h-1 Mpc, the richest systems of quasars have diameters exceeding 500 h-1 Mpc. Quasar luminosities in systems are not correlated with the system richness. Conclusions: Quasar system catalogues in our web pages and at the Strasbourg Astronomical Data Center (CDS) serve as a database for searching superclusters of galaxies and for tracing the cosmic web at high redshifts. Appendix A is available in electronic form at http://www.aanda.orgThe catalogues are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc

  13. The formation and evolution of high-redshift dusty galaxies

    Science.gov (United States)

    Ma, Jingzhe; Gonzalez, Anthony H.; Ge, Jian; Vieira, Joaquin D.; Prochaska, Jason X.; Spilker, Justin; Strandet, Maria; Ashby, Matthew; Noterdaeme, Pasquier; Lundgren, Britt; Zhao, Yinan; Ji, Tuo; Zhang, Shaohua; Caucal, Paul; SPT SMG Collaboration

    2017-01-01

    Star formation and chemical evolution are among the biggest questions in galaxy formation and evolution. High-redshift dusty galaxies are the best sites to investigate mass assembly and growth, star formation rates, star formation history, chemical enrichment, and physical conditions. My thesis is based on two populations of high-redshift dusty galaxies, submillimeter galaxies (SMGs) and quasar 2175 Å dust absorbers, which are selected by dust emission and dust absorption, respectively.For the SMG sample, I have worked on the gravitationally lensed dusty, star-forming galaxies (DSFGs) at 2.8 thesis is focused on the stellar masses and star formation rates of these objects by means of multi-wavelength spectral energy distribution (SED) modelling. The data include HST/WFC3, Spitzer/IRAC, Herschel/PACS, Herschel/SPIRE, APEX/Laboca and SPT. Compared to the star-forming main sequence (MS), these DSFGs have specific SFRs that lie above the MS, suggesting that we are witnessing ongoing strong starburst events that may be driven by major mergers. SPT0346-52 at z = 5.7, the most extraordinary source in the SPT survey for which we obtained Chandra X-ray and ATCA radio data, was confirmed to have the highest star formation surface density of any known galaxy at high-z.The other half of my thesis is focused on a new population of quasar absorption line systems, 2175 Å dust absorbers, which are excellent probes of gas and dust properties, chemical evolution and physical conditions in the absorbing galaxies. This sample was selected from the SDSS and BOSS surveys and followed up with the Echelle Spectrographs and Imager on the Keck-II telescope, the Red & Blue Channel Spectrograph on the Multiple Mirror Telescope, and the Ultraviolet and Visible Echelle Spectrograph onboard the Very Large Telescope. We found a correlation between the presence of the 2175 Å bump and other ingredients including high metallicity, high depletion level, overall low ionization state of gas, neutral

  14. Constraints from high redshift supernovae upon scalar field cosmologies

    Energy Technology Data Exchange (ETDEWEB)

    Frieman, J.A. [NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois60510 (United States)]|[Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois60637 (United States); Waga, I. [Universidade Federal do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro, RJ, 21945-970 (Brazil)

    1998-04-01

    Recent observations of high-redshift type Ia supernovae have placed stringent constraints on the cosmological constant {Lambda}. We explore the implications of these SNe observations for cosmological models in which a classically evolving scalar field currently dominates the energy density of the Universe. Such models have been shown to share the advantages of {Lambda} models: compatibility with the spatial flatness predicted by inflation; a Universe older than the standard Einstein{endash}de Sitter model; and, combined with cold dark matter, predictions for large-scale structure formation in good agreement with data from galaxy surveys. Compared to the cosmological constant, these scalar field models are consistent with the SNe observations for a lower matter density, {Omega}{sub m0}{approximately}0.2, and a higher age, H{sub 0}t{sub 0}{approx_gt}1. Combined with the fact that scalar field models imprint a distinctive signature on the cosmic microwave background anisotropy, they remain currently viable and should be testable in the near future. {copyright} {ital 1998} {ital The American Physical Society}

  15. Angular Momentum Evolution Of Disk Galaxies At High Redshift

    Science.gov (United States)

    Okamura, Taku; Kazuhiro, Shimasaku; Ryota, Kawamata

    2017-06-01

    The stellar disk size of a galaxy depends on the fraction of the dark-halo mass settled as disk stars, m★= M★/Mdh, and the fraction of the dark-halo angular momentum transferred to the disk, j★ = J★/Jdh. Since j★ is also determined by various star-formation related mechanisms such as inflows and feedbacks, measuring j★ and m★ at high redshifts is needed to understand the formation history of disk galaxies. We use the 3D-HST GOODS-S, COSMOS, and AEGIS imaging data and photo-z catalogs to examine j★ and m★ for star-forming galaxies at z 2,3,4, when disks are actively forming. We find that the j★/m★ ratio is roughly constant at ≃ 0.8 for all three redshifts over the entire halo mass range examined. This high ratio is close to those of local disk galaxies but a factor of a few higher than predicted (at z 2) by galaxy formation models. We also find that a significant fraction of our galaxies appear to be unstable against bar formation.

  16. Magnetically Regulated Gas Accretion in High-Redshift Galactic Disks

    Science.gov (United States)

    Birnboim, Yuval

    2009-09-01

    Disk galaxies are in hydrostatic equilibrium along their vertical axis. The pressure allowing for this configuration consists of thermal, turbulent, magnetic, and cosmic-ray components. For the Milky Way the thermal pressure contributes ~10% of the total pressure near the plane, with this fraction dropping toward higher altitudes. Out of the rest, magnetic fields contribute ~1/3 of the pressure to distances of ~3 kpc above the disk plane. In this Letter, we attempt to extrapolate these local values to high-redshift, rapidly accreting, rapidly star-forming disk galaxies and study the effect of the extra pressure sources on the accretion of gas onto the galaxies. In particular, magnetic field tension may convert a smooth cold-flow accretion to clumpy, irregular star formation regions and rates. The infalling gas accumulates on the edge of the magnetic fields, supported by magnetic tension. When the mass of the infalling gas exceeds some threshold mass, its gravitational force cannot be balanced by magnetic tension anymore, and it falls toward the disk's plane, rapidly making stars. Simplified estimations of this threshold mass are consistent with clumpy star formation observed in SINS, UDF, GOODS, and GEMS surveys. We discuss the shortcomings of pure hydrodynamic codes in simulating the accretion of cold flows into galaxies, and emphasize the need for magnetohydrodynamic simulations.

  17. Galaxy Merger Candidates in High-redshift Cluster Environments

    Science.gov (United States)

    Delahaye, A. G.; Webb, T. M. A.; Nantais, J.; DeGroot, A.; Wilson, G.; Muzzin, A.; Yee, H. K. C.; Foltz, R.; Noble, A. G.; Demarco, R.; Tudorica, A.; Cooper, M. C.; Lidman, C.; Perlmutter, S.; Hayden, B.; Boone, K.; Surace, J.

    2017-07-01

    We compile a sample of spectroscopically and photometrically selected cluster galaxies from four high-redshift galaxy clusters (1.59Red-Sequence Cluster Survey (SpARCS), and a comparison field sample selected from the UKIDSS Deep Survey. Using near-infrared imaging from the Hubble Space Telescope, we classify potential mergers involving massive ({M}* ≥slant 3× {10}10 {M}⊙ ) cluster members by eye, based on morphological properties such as tidal distortions, double nuclei, and projected near neighbors within 20 kpc. With a catalog of 23 spectroscopic and 32 photometric massive cluster members across the four clusters and 65 spectroscopic and 26 photometric comparable field galaxies, we find that after taking into account contamination from interlopers, {11.0}-5.6+7.0 % of the cluster members are involved in potential mergers, compared to {24.7}-4.6+5.3 % of the field galaxies. We see no evidence of merger enhancement in the central cluster environment with respect to the field, suggesting that galaxy-galaxy merging is not a stronger source of galaxy evolution in cluster environments compared to the field at these redshifts.

  18. The infrared-dark dust content of high redshift galaxies

    Science.gov (United States)

    Ferrara, A.; Hirashita, H.; Ouchi, M.; Fujimoto, S.

    2017-11-01

    We present a theoretical model aimed at explaining the IRX-β relation for high redshift (z ≳ 5) galaxies. Recent observations have shown that early Lyman-Break Galaxies, although characterized by a large ultraviolet (UV) attenuation (e.g. flat UV β slopes), show a striking far-infrared (FIR) deficit, i.e. they are `infrared-dark'. This marked deviation from the local IRX-β relation can be explained by the larger molecular gas content of these systems. While dust in the diffuse interstellar medium attains relatively high temperatures (Td ≃ 45 K for typical size a = 0.1 μm; smaller grains can reach Td ≳ 60 K), a sizable fraction of the dust mass is embedded in dense gas, and therefore remains cold. If confirmed, the FIR deficit might represent a novel, powerful indicator of the molecular content of high-z galaxies which can be used to pre-select candidates for follow-up deep CO observations. Thus, high-z CO line searches with ALMA might be much more promising than currently thought.

  19. Large fluctuations in the high-redshift metagalactic ionizing background

    Science.gov (United States)

    D'Aloisio, Anson; McQuinn, Matthew; Davies, Frederick B.; Furlanetto, Steven R.

    2018-01-01

    Recent observations have shown that the scatter in opacities amongst coeval segments of the Ly α forest increases rapidly at z > 5. In this paper, we assess whether the large scatter can be explained by fluctuations in the ionizing background in the post-reionization intergalactic medium. We find that matching the observed scatter at z ≈ 5.5 requires a short spatially averaged mean free path of 〈λmfp912〉 ≲ 15 h- 1 comoving Mpc, a factor of ≳3 shorter than direct measurements at z = 5.2. We argue that such rapid evolution in the mean free path is difficult to reconcile with our measurements of the global H I photoionization rate, which stay approximately constant over the interval z ≈ 4.8-5.5. However, we also show that measurements of the mean free path at z > 5 are likely biased towards higher values by the quasar proximity effect. This bias can reconcile the short values of 〈λmfp912〉 that are required to explain the large scatter in opacities. We discuss the implications of this scenario for cosmological reionization. Finally, we investigate whether other statistics applied to the z > 5 Ly α forest can shed light on the origin of the scatter. Compared to a model with a uniform ionizing background, models that successfully account for the scatter lead to enhanced power in the line-of-sight flux power spectrum on scales k ≲0.1 h Mpc-1. We find tentative evidence for this enhancement in observations of the high-redshift Ly α forest.

  20. Identifying gamma-ray bursts at very high redshifts

    Science.gov (United States)

    Tanvir, Nial

    2017-08-01

    Gamma-ray bursts are bright enough to be seen to very great distances and their afterglows can provide redshifts and positions for their host galaxies, and in some cases details of the ISM and the IGM close to the burst, irrespective of the host magnitude itself. Thus GRBs, despite their small numbers, offer a unique and powerful tracer of early star formation and the galaxy populations in the era of reionization. Our efforts to identify high-z GRBs have been rewarded with the discoveries of GRB 090423 and GRB 120923A at spectroscopic redshifts of 8.2 and 7.8 respectively. However, it remains the case that some good candidate high-z GRBs cannot be followed up quickly or deeply enough with ground-based IR spectroscopy, and indeed for others the Ly-alpha break may fall in regions of the IR spectrum difficult to access from the ground. GRB 090429B is an example, which had a photo-z of 9.4, but for which spectroscopy was curtailed due to bad weather. WFC3/IR on HST can obtain redshifts based on the location of the Ly-alpha break via slitless grism spectroscopy to considerably deeper limits (and hence later times) than is possible from the ground, thus offering a solution to this problem. This proposal aims to continue to build the sample of z>7 GRBs by obtaining spectroscopy for up to two candidates for which photometry suggests a very high redshift, but where the redshift could not be secured from the ground. This will provide an important legacy of host galaxy targets with known redshifts for future studies with JWST. The low rate of z>7 GRBs leads us to request a long-term ToO program, spanning cycles 25 and 26.

  1. Probing the Intergalactic Medium with high-redshift quasars

    Science.gov (United States)

    Calverley, Alexander Peter

    2011-11-01

    Clues about the timing of reionization and the nature of the ionizing sources responsible are imprinted in the ionization and thermal state of the IGM. In this thesis, I use high-resolution quasar spectra in conjunction with state-of-the-art hydrodynamical simulations to probe the IGM at high redshift, focusing on the ionization and thermal state of the gas. After reionization, the ionization state of the IGM is set by the intensity of the ultraviolet background (UVB), quantified by the hydrogen photoionization rate, Γ_bkg. At high redshifts this has been estimated by measuring the mean flux in the Lyα forest, and scaling Γ_bkg in simulations such that the simulated mean flux matches the observed value. In Chapter 3 I investigate whether the precision of these estimates can be improved by using the entire flux probability distribution function (PDF) instead of only the mean flux. Although I find it cannot improve the precision directly, the flux PDF can potentially be used to constrain other sources of error in observational estimates of Γ_bkg, and so may increase the precision indirectly. The ionizing output of a quasar will locally dominate over the UVB, and this leads to enhanced transmission bluewards of the quasar Lyα line, known as the proximity effect. In Chapter 4 I present the first measurements of Γ_bkg at z > 5 from the proximity effect. The UVB intensity declines smoothly with redshift over 4.6 6.4. There is a drop in Γ_bkg by roughly a factor of five, which corresponds to a drop in the ionizing emissivity by about a factor of two. Such a redshift evolution in the emissivity cannot continue to much higher redshift without reionization failing to complete, which suggests that reionization cannot have ended much higher than z = 6.4. Estimates of Γ_bkg from the proximity effect and the mean flux are generally discrepant at z ∼ 2-4, with those from the proximity effect systematically higher. This is generally attributed to effects of the

  2. Quantitative comparison between Type Ia supernova spectra at low and high redshifts: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Supernova Cosmology Project; Nugent, Peter E; Garavini, G.; Folatelli, G.; Nobili, S.; Aldering, G.; Amanullah, R.; Antilogus, P.; Astier, P.; Blanc, G.; Bronder, J.; Burns, M.S.; Conley, A.; Deustua, S. E.; Doi, M.; Fabbro, S.; Fadeyev, V.; Gibbons, R.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hook, I.; Howell, D. A.; Kashikawa, N.; Kim, A. G.; Kowalski, M.; Kuznetsova, N.; Lee, B. C.; Lidman, C.; Mendez, J.; Morokuma, T.; Motohara, K.; Nugent, P. E.; Pain, R.; Perlmutter, S.; Quimby, R.; Raux, J.; Regnault, N.; Ruiz-Lapuente, P.; Sainton, G.; Schahmaneche, K.; Smith, E.; Spadafora, A. L.; Stanishev, V.; Thomas, R. C.; Walton, N. A.; Wang, L.; Wood-Vasey, W. M.; Yasuda, N.

    2008-03-24

    We develop a method to measure the strength of the absorption features in type Ia supernova (SN Ia) spectra and use it to make a quantitative comparisons between the spectra of type Ia supernovae at low and high redshifts. In this case study, we apply the method to 12 high-redshift (0.212 = z = 0.912) SNe Ia observed by the Supernova Cosmology Project. Through measurements of the strengths of these features and of the blueshift of theabsorption minimum in Ca ii H&K, we show that the spectra of the high-redshift SNe Ia are quantitatively similar to spectra of nearby SNe Ia (z< 0.15). One supernova in our high redshift sample, SN 2002fd at z = 0.279, is found to have spectral characteristics that are associated with peculiar SN 1991T/SN 1999aa-like supernovae.

  3. High-redshift gamma-ray bursts: observational signatures of superconducting cosmic strings?

    Science.gov (United States)

    Cheng, K S; Yu, Yun-Wei; Harko, T

    2010-06-18

    The high-redshift gamma-ray bursts (GRBs), GRBs 080913 and 090423, challenge the conventional GRB progenitor models by their short durations, typical for short GRBs, and their high energy releases, typical for long GRBs. Meanwhile, the GRB rate inferred from high-redshift GRBs also remarkably exceeds the prediction of the collapsar model, with an ordinary star formation history. We show that all these contradictions could be eliminated naturally, if we ascribe some high-redshift GRBs to electromagnetic bursts of superconducting cosmic strings. High-redshift GRBs could become a reasonable way to test the superconducting cosmic string model because the event rate of cosmic string bursts increases rapidly with increasing redshifts, whereas the collapsar rate decreases.

  4. Rapid formation of massive black holes in close proximity to embryonic protogalaxies

    Science.gov (United States)

    Regan, John A.; Visbal, Eli; Wise, John H.; Haiman, Zoltán; Johansson, Peter H.; Bryan, Greg L.

    2017-03-01

    The appearance of supermassive black holes at very early times1-3 in the Universe is a challenge to our understanding of star and black hole formation. The direct-collapse4,5 black hole scenario provides a potential solution. A prerequisite for forming a direct-collapse black hole is that the formation of (much less massive) population III stars be avoided6,7; this can be achieved by destroying H2 by means of Lyman-Werner radiation (photons of energy around 12.6 eV). Here we show that two conditions must be met in the protogalaxy that will host the direct-collapse black hole. First, prior star formation must be delayed; this can be achieved with a background Lyman-Werner flux of JBG ≳ 100J21 (J21 is the intensity of background radiation in units of 10-21 erg cm-2 s-1 Hz-1 sr-1). Second, an intense burst of Lyman-Werner radiation from a neighbouring star-bursting protogalaxy is required, just before the gas cloud undergoes gravitational collapse, to suppress star formation completely. Using high-resolution hydrodynamical simulations that include full radiative transfer, we find that these two conditions inevitably move the host protogalaxy onto the isothermal atomic cooling track, without the deleterious effects of either photo-evaporating the gas or polluting it with heavy elements. These atomically cooled, massive protogalaxies are expected ultimately to form a direct-collapse black hole of mass 104-105M⊙.

  5. The potential of INTEGRAL for the detection of high redshift GRBs

    DEFF Research Database (Denmark)

    Gorosabel, J.; Lund, Niels; Brandt, Søren Kristian

    2004-01-01

    We discuss INTEGRAL's ability to detect a high redshift population of Gamma-Ray Bursts (GRBs) in comparison to other high-energy missions. Emphasis is placed on the study of the relative capabilities of IBIS on board INTEGRAL with respect to SWIFT and HETE 2 in detecting a high redshift population...... of GRBs. We conclude that, if the GRB rate is proportional to the star formation rate, INTEGRAL's ability to study GRBs are complementary to the ones of missions like SWIFT and HETE 2, devoted to prompt localisations of GRBs. Whereas SWIFT and HETE 2 would detect a higher number of GRBs than INTEGRAL......, IBIS might be able to detect high redshift (z greater than or similar to 7) GRBs, unreachable by SWIFT and HETE 2. We discuss the relevance of performing near-infrared (NIR) observations of the INTEGRAL GRBs and the strategy that large-class telescopes might follow....

  6. Science from the Avo 1ST Light: the High Redshift Universe

    Science.gov (United States)

    Walton, Nicholas A.

    The Astrophysical Virtual Observatory science working group defined a number of key science drivers for which the AVO should develop capabilities. At the AVO's Jan 2003 'First Light' event the AVO prototype data access and manipulation tool was demonstrated. In particular its use in enabling discovery in deep multi wavelength data sets was highlighted. In this presentation I will describe how the AVO demonstrator has enabled investigation into the high redshift universe and in particular its use in discovering rare populations of high redshift galaxies from deep Hubble and ground based imaging data obtained through the Great Observatories Origins Deep Survey (GOODS) programme.

  7. Expanding the Gamma-ray Universe: High Redshift Fermi-LAT Blazars

    Science.gov (United States)

    Ojha, Roopesh; Paliya, Vaidehi; Gasparrini, Dario; Ajello, Marco; Cutini, Sara; Fermi-LAT Collaboration

    2017-01-01

    High-redshift blazars detected by the Fermi Large Area Telescope (LAT) are of great astrophysical import as they are extreme objects whose energetics remain a mystery. Such blazars are intrinsically interesting since they inform us about the evolution of gamma-ray blazars and are, by definition, some of the more luminous blazars in the Fermi-LAT sample. These blazars appear to host very massive black holes and could shed light on the origin and growth of black holes in the early Universe. We present the latest high redshift blazar detections in the LAT and discuss some of their implications.

  8. Constraining omega from X-ray properties of clusters of galaxies at high redshifts

    DEFF Research Database (Denmark)

    Sadat, R.; Blanchard, A.; Oukbir, J.

    1997-01-01

    Properties of high redshift clusters are a fundamental source of information for cosmology. It has been shown by Oukbir and Blanchard (1997) that the combined knowledge of the redshift distribution of X-ray clusters of galaxies and the luminosity-temperature correlation, L-X - T-X, provides a pow...

  9. High-redshift Ly alpha emitters : clues on the Milky Way infancy

    NARCIS (Netherlands)

    Salvadori, Stefania; Dayal, Pratika; Ferrara, Andrea

    With the aim of determining if Milky Way (MW) progenitors could be identified as high-redshift Lyman Alpha Emitters (LAEs), we have derived the intrinsic properties of z approximate to 5.7 MW progenitors, which are then used to compute their observed Ly alpha luminosity, L(alpha), and equivalent

  10. Planck intermediate results XXXIX. The Planck list of high-redshift source candidates

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Arnaud, M.

    2016-01-01

    The Planck mission, thanks to its large frequency range and all-sky coverage, has a unique potential for systematically detecting the brightest, and rarest, submillimetre sources on the sky, including distant objects in the high-redshift Universe traced by their dust emission. A novel method, bas...

  11. FeII/MgII Emission Line Ratio in High Redshift Quasars

    DEFF Research Database (Denmark)

    Dietrich, M.; Hamann, F.; Appenzeller, I.

    2003-01-01

    We present results of the analysis of near infrared spectroscopic observations of 6 high-redshift quasars (z > 4), emphasizing the measurement of the ultraviolet FeII/MgII emission line strength in order to estimate the beginning of intense star formation in the early universe. To investigate the...

  12. The rest-frame submillimeter spectrum of high-redshift, dusty, star-forming galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Spilker, J. S.; Marrone, D. P. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Aguirre, J. E. [University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Aravena, M. [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001 Vitacura Santiago (Chile); Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Béthermin, M. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CEA-Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Bradford, C. M. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Bothwell, M. S. [Cavendish Laboratory, University of Cambridge, JJ Thompson Ave, Cambridge CB3 0HA (United Kingdom); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Carlstrom, J. E.; Crawford, T. M. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Chapman, S. C. [Dalhousie University, Halifax, Nova Scotia (Canada); De Breuck, C.; Gullberg, B. [European Southern Observatory, Karl Schwarzschild Straße 2, D-85748 Garching (Germany); Fassnacht, C. D. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Gonzalez, A. H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Hezaveh, Y. [Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8 (Canada); Holzapfel, W. L., E-mail: jspilker@as.arizona.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); and others

    2014-04-20

    We present the average rest-frame spectrum of high-redshift dusty, star-forming galaxies from 250 to 770 GHz. This spectrum was constructed by stacking Atacama Large Millimeter/submillimeter Array (ALMA) 3 mm spectra of 22 such sources discovered by the South Pole Telescope and spanning z = 2.0-5.7. In addition to multiple bright spectral features of {sup 12}CO, [C I], and H{sub 2}O, we also detect several faint transitions of {sup 13}CO, HCN, HNC, HCO{sup +}, and CN, and use the observed line strengths to characterize the typical properties of the interstellar medium of these high-redshift starburst galaxies. We find that the {sup 13}CO brightness in these objects is comparable to that of the only other z > 2 star-forming galaxy in which {sup 13}CO has been observed. We show that the emission from the high-critical density molecules HCN, HNC, HCO{sup +}, and CN is consistent with a warm, dense medium with T {sub kin} ∼ 55 K and n{sub H{sub 2}}≳10{sup 5.5} cm{sup –3}. High molecular hydrogen densities are required to reproduce the observed line ratios, and we demonstrate that alternatives to purely collisional excitation are unlikely to be significant for the bulk of these systems. We quantify the average emission from several species with no individually detected transitions, and find emission from the hydride CH and the linear molecule CCH for the first time at high redshift, indicating that these molecules may be powerful probes of interstellar chemistry in high-redshift systems. These observations represent the first constraints on many molecular species with rest-frame transitions from 0.4 to 1.2 mm in star-forming systems at high redshift, and will be invaluable in making effective use of ALMA in full science operations.

  13. The High-Redshift Clusters Occupied by Bent Radio AGN (COBRA) Survey

    Science.gov (United States)

    Paterno-Mahler, Rachel; Blanton, Elizabeth L.; Wing, Joshua; Ashby, M. L. N.; Brodwin, Mark; Golden-Marx, Emmet

    The number of confirmed, high-redshift galaxy clusters is very low compared to the number of well-studied clusters nearby. Bent, double-lobed radio sources are frequently found in galaxy clusters, and thus can be used as tracers for efficiently locating high-redshift clusters. Using our Spitzer Snapshot Survey, we have identified approximately 300 potential new clusters with redshifts 0.7 COBRA) survey. We have created color-magnitude diagrams using infrared and optical data. Using the colors of the radio source host and the red sequence we can estimate redshifts for our clusters, as well as examine the evolution of the cluster galaxies over a large range of cosmic time.

  14. Detecting Massive, High-Redshift Galaxy Clusters Using the Thermal Sunyaev-Zel'dovich Effect

    Science.gov (United States)

    Adams, Carson; Steinhardt, Charles L.; Loeb, Abraham; Karim, Alexander; Staguhn, Johannes; Erler, Jens; Capak, Peter L.

    2017-01-01

    We develop the thermal Sunyaev-Zel'dovich (SZ) effect as a direct astrophysical measure of the mass distribution of dark matter halos. The SZ effect increases with cosmological distance, a unique astronomical property, and is highly sensitive to halo mass. We find that this presents a powerful methodology for distinguishing between competing models of the halo mass function distribution, particularly in the high-redshift domain just a few hundred million years after the Big Bang. Recent surveys designed to probe this epoch of initial galaxy formation such as CANDELS and SPLASH report an over-abundance of highly massive halos as inferred from stellar ultraviolet (UV) luminosities and the stellar mass to halo mass ratio estimated from nearby galaxies. If these UV luminosity to halo mass relations hold to high-redshift, observations estimate several orders of magnitude more highly massive halos than predicted by hierarchical merging and the standard cosmological paradigm. Strong constraints on the masses of these galaxy clusters are essential to resolving the current tension between observation and theory. We conclude that detections of thermal SZ sources are plausible at high-redshift only for the halo masses inferred from observation. Therefore, future SZ surveys will provide a robust determination between theoretical and observational predictions.

  15. Lyman Break Analogs: Constraints on the Formation of Extreme Starbursts at Low and High Redshift

    Science.gov (United States)

    Goncalves, Thiago S.; Overzier, Roderik; Basu-Zych, Antara; Martin, D. Christopher

    2011-01-01

    Lyman Break Analogs (LBAs), characterized by high far-UV luminosities and surface brightnesses as detected by GALEX, are intensely star-forming galaxies in the low-redshift universe (z approximately equal to 0.2), with star formation rates reaching up to 50 times that of the Milky Way. These objects present metallicities, morphologies and other physical properties similar to higher redshift Lyman Break Galaxies (LBGs), motivating the detailed study of LBAs as local laboratories of this high-redshift galaxy population. We present results from our recent integral-field spectroscopy survey of LBAs with Keck/OSIRIS, which shows that these galaxies have the same nebular gas kinematic properties as high-redshift LBGs. We argue that such kinematic studies alone are not an appropriate diagnostic to rule out merger events as the trigger for the observed starburst. Comparison between the kinematic analysis and morphological indices from HST imaging illustrates the difficulties of properly identifying (minor or major) merger events, with no clear correlation between the results using either of the two methods. Artificial redshifting of our data indicates that this problem becomes even worse at high redshift due to surface brightness dimming and resolution loss. Whether mergers could generate the observed kinematic properties is strongly dependent on gas fractions in these galaxies. We present preliminary results of a CARMA survey for LBAs and discuss the implications of the inferred molecular gas masses for formation models.

  16. Epizootiological-epidemiological importance of parasitic infections in wild canids

    Directory of Open Access Journals (Sweden)

    Ilić Tamara

    2012-01-01

    Full Text Available The family of wild canids belongs to the order Carnivora and comprises 16 genuses that are distributed in most countries all over the world. The most important endoparasitic diseases of wild canids are toxocariasis, uncinariasis, capillariasis, trichinellosis, echinococcosis, cestodiasis, opisthorchiasis, and alariasis. Ectoparasites that most often exist as parasites in wild canids are mites, fleas, ticks and scabies.Wild canids have a large epizootiological-epidemiological significance since they are hosts to parasites that cause certain vector diseases, the most important of which are leishmaniasis, ehrilichiosis, babesiasis, borreliosis, dirofilariasis, bartonellosis, and hepatozoonosis. The increased frequency of interaction between domestic and wild canids steps up the risk of the appearance, spread, and maintaining of the disease in domestic dog populations. Observed from the aspect of the biological and ecological risk, that can be caused by zoonotic infections, the knowledge of the etiology and epizootiology of parasistic infections of wild canids is of particular importance for the region of the Republic of Serbia. [Projekat Ministarstva nauke Republike Srbije, br. TR31084: Praćenje zdravstvenog stanja divljači i uvođenje novih biotehnoloških postupaka u detekciji zaraznih i zoonoznih agenasa - analiza rizika za zdravlje ljudi, domaćih i divljih životinja i kontaminaciju životne sredine i br. 173001: Primena EIIP/ISM bioinformatičke platforme u otkrivanju novih terapeutskih targeta i potencijalnih terapeutskih molekula

  17. Using r-process enhanced galaxies to estimate the neutron star merger rate at high redshift

    Science.gov (United States)

    Roederer, Ian

    2018-01-01

    The rapid neutron-capture process, or r-process, is one of the fundamental ways that stars produce heavy elements. I describe a new approach that uses the existence of r-process enhanced galaxies, like the recently discovered ultra-faint dwarf galaxy Reticulum II, to derive a rate for neutron star mergers at high redshift. This method relies on three assertions. First, several lines of reasoning point to neutron star mergers as a rare yet prolific producer of r-process elements, and one merger event is capable of enriching most of the stars in a low-mass dwarf galaxy. Second, the Local Group is cosmologically representative of the halo mass function at the mass scales of low-luminosity dwarf galaxies, and the volume that their progenitors spanned at high redshifts can be estimated from simulations. Third, many of these dwarf galaxies are extremely old, and the metals found in their stars today date from the earliest times at high redshift. These galaxies occupy a quantifiable volume of the Universe, from which the frequency of r-process enhanced galaxies can be estimated. This frequency may be interpreted as lower limit to the neutron star merger rate at a redshift (z ~ 5-10) that is much higher than is accessible to gravitational wave observatories. I will present a proof of concept demonstration using medium-resolution multi-object spectroscopy from the Michigan/Magellan Fiber System (M2FS) to recover the known r-process galaxy Reticulum II, and I will discuss future plans to apply this method to other Local Group dwarf galaxies.

  18. The fate of high redshift massive compact galaxies in dense environments

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Tobias; /Zurich, ETH; Mayer, Lucio; /Zurich U.; Carollo, Marcella; /Zurich, ETH; Feldmann, Robert; /Fermilab /Chicago U., KICP

    2012-01-01

    Massive compact galaxies seem to be more common at high redshift than in the local universe, especially in denser environments. To investigate the fate of such massive galaxies identified at z {approx} 2 we analyse the evolution of their properties in three cosmological hydrodynamical simulations that form virialized galaxy groups of mass {approx} 10{sup 13} M{sub {circle_dot}} hosting a central massive elliptical/S0 galaxy by redshift zero. We find that at redshift {approx} 2 the population of galaxies with M{sub *} > 2 x 10{sup 10} M{sub {circle_dot}} is diverse in terms of mass, velocity dispersion, star formation and effective radius, containing both very compact and relatively extended objects. In each simulation all the compact satellite galaxies have merged into the central galaxy by redshift 0 (with the exception of one simulation where one of such satellite galaxy survives). Satellites of similar mass at z = 0 are all less compact than their high redshift counterparts. They form later than the galaxies in the z = 2 sample and enter the group potential at z < 1, when dynamical friction times are longer than the Hubble time. Also, by z = 0 the central galaxies have increased substantially their characteristic radius via a combination of in situ star formation and mergers. Hence in a group environment descendants of compact galaxies either evolve towards larger sizes or they disappear before the present time as a result of the environment in which they evolve. Since the group-sized halos that we consider are representative of dense environments in the {Lambda}CDM cosmology, we conclude that the majority of high redshift compact massive galaxies do not survive until today as a result of the environment.

  19. Local Counterparts to High-Redshift Turbulent Galaxies: What are the Stellar Kinematics?

    Science.gov (United States)

    Bassett, Robert; Glazebrook, Karl; Fisher, David; Abraham, Roberto; Damjanov, Ivana

    2014-02-01

    We aim to measure the stellar kinematics of 4 low redshift turbulent, clumpy disks with the GMOS IFU. Recent observations of high redshift galaxies show that gaseous disks in high redshift (z 2) galaxies are turbulent. The source of this turbulence remains an open question. A possible scenario is that turbulent disks are fed by streams of cold gas, flowing along cosmic filaments, which drive the large H-alpha velocity dispersions and clumpy star formation observed (for example by the SINS survey). However, the recent discovery of low redshift disk galaxies with clumpy-high velocity dispersion disks shows that galaxies with similar properties to high-z clumpy disks can exists in absence of cold flows, therefore an alternate driver for turbulence seems likely to explain, at least these nearby galaxies. A contrasting scenario is that the turbulence is driven by feedback from extreme star formation originating from a thin stellar disk. These nearby star forming disks are very rare, yet they provide an oppurtunity to study clumpy disks with techniques which are impossible at high redshift (due to both resolution and surface brightness dimming). Here we propose one such study, to measure the stellar kinematics from Balmer absorption lines. If the stars and gas have similar velocity dispersion, this would favor externally driven turbulence by gas accretion (a rare thing in the low redshift Universe); conversely if the gas and stars have different dynamics then this would suggest that internally driven turbelence from feedback is a plausible scenario. We currently have GMOS IFU observations of two disk systems, and we propose here to extend our sample. To identify galaxies as disks we use lower resolution IFU emission line kinematics from AAO, surface photometry from UKIDSS and SDSS, and Halpha maps from Hubble Space Telescope.

  20. FINDING HIGH-REDSHIFT DARK STARS WITH THE JAMES WEBB SPACE TELESCOPE

    OpenAIRE

    Zackrisson, Erik; Scott, Pat; Rydberg, Claes-Erik; Iocco, Fabio; Edvardsson, Bengt; Ostlin, Goran; Sivertsson, Sofia; Zitrin, Adi; Broadhurst, Tom; Gondolo, Paolo

    2010-01-01

    The first stars in the history of the universe are likely to form in the dense central regions of similar to 10(5)-10(6) M-circle dot cold dark matter halos at z approximate to 10-50. The annihilation of dark matter particles in these environments may lead to the formation of so-called dark stars, which are predicted to be cooler, larger, more massive, and potentially more long-lived than conventional population III stars. Here, we investigate the prospects of detecting high-redshift dark sta...

  1. The Main Sequences of Star-forming Galaxies and Active Galactic Nuclei at High Redshift

    Science.gov (United States)

    Mancuso, C.; Lapi, A.; Shi, J.; Cai, Z.-Y.; Gonzalez-Nuevo, J.; Béthermin, M.; Danese, L.

    2016-12-01

    We provide a novel, unifying physical interpretation on the origin, average shape, scatter, and cosmic evolution for the main sequences of star-forming galaxies and active galactic nuclei (AGNs) at high redshift z≳ 1. We achieve this goal in a model-independent way by exploiting: (i) the redshift-dependent star formation rate functions based on the latest UV/far-IR data from HST/Herschel, and related statistics of strong gravitationally lensed sources; (ii) deterministic evolutionary tracks for the history of star formation and black hole accretion, gauged on a wealth of multiwavelength observations including the observed Eddington ratio distribution. We further validate these ingredients by showing their consistency with the observed galaxy stellar mass functions and AGN bolometric luminosity functions at different redshifts via the continuity equation approach. Our analysis of the main sequence for high-redshift galaxies and AGNs highlights that the present data are consistently interpreted in terms of an in situ coevolution scenario for star formation and black hole accretion, envisaging these as local, time-coordinated processes.

  2. Dust Formation, Evolution, and Obscuration Effects in the Very High-Redshift Universe

    Science.gov (United States)

    Dwek, Eli; Staguhn, Johannes; Arendt, Richard G.; Kovacs, Attila; Su, Ting; Benford, Dominic J.

    2014-01-01

    The evolution of dust at redshifts z > or approx. 9, and consequently the dust properties, differs greatly from that in the local universe. In contrast to the local universe, core collapse supernovae (CCSNe) are the only source of thermally-condensed dust. Because of the low initial dust-to-gas mass ratio, grain destruction rates are low, so that CCSNe are net producers of interstellar dust. Galaxies with large initial gas mass or high mass infall rate will therefore have a more rapid net rate of dust production comported to galaxies with lower gas mass, even at the same star formation rate. The dust composition is dominated by silicates, which exhibit a strong rise in the UV opacity near the Lyman break. This "silicate-UV break" may be confused with the Lyman break, resulting in a misidentification of a galaxies' photometric redshift. In this paper we demonstrate these effects by analyzing the spectral energy distribution (SED) of MACS1149-JD, a lensed galaxy at z = 9.6. A potential 2mm counterpart of MACS1149-JD has been identified with GISMO. While additional observations are required to corroborate this identification, we use this possible association to illustrate the physical processes and the observational effects of dust in the very high redshift universe. Subject headings: galaxies: high-redshift - galaxies: evolution - galaxies: individual (MACS1149- JD) - Interstellar medium (ISM), nebulae: dust, extinction - physical data and processes: nuclear reactions, nucleosynthesis, abundances.

  3. Highlights And Shadows Of High Redshift Starbursts: A Herschel­Fmos Joint Effort

    Science.gov (United States)

    Puglisi, Annagrazia

    2017-06-01

    Starburst galaxies represent a critical stage in galaxy evolution as they are the likely progenitors of passively evolving ellipticals. The properties of high-redshift starbursts are however still debated as it is not clear to which extent their vigorous star formation rate is caused by an enhanced gas fraction or an enhanced star formation efficiency, and what physical processes trigger such violent activity. Our study of the rest-frame optical spectra from the FMOS-COSMOS survey of twelve z 1.6 Herschel starbursts combined with a rich ancillary data-set from UV to ALMA, is shedding light on some of these questions. By measuring the nebular extinction from different indicators, we find that 90% of their extreme SFR arises from an heavily obscured component which is thick in the optical. We also measure their gas-phase metallicity, showing that starbursts are metal-rich outliers from the metallicity-SFR anticorrelation observed at fixed stellar mass for the main sequence population. Our findings are consistent with a major merger origin for the starburst event. I will present this study discussing its implications on our interpretation of the high-redshift starbursts physics. I will also briefly discuss possible extensions of this work with the future PFS survey and how we can take advantage of the IFU capabilities of JWST/NIRspec to unveil the complex structure of these elusive systems.

  4. Five New High-Redshift Quasar Lenses from the Sloan Digital Sky Survey

    Energy Technology Data Exchange (ETDEWEB)

    Inada, Naohisa; Oguri, Masamune; Shin, Min-Su; Kayo, Issha; Strauss, Michael A.; Morokuma, Tomoki; Schneider, Donald P.; Becker, Robert H.; Bahcall, Neta A.; York, Donald G.

    2008-09-08

    We report the discovery of five gravitationally lensed quasars from the Sloan Digital Sky Survey (SDSS). All five systems are selected as two-image lensed quasar candidates from a sample of high-redshift (z > 2.2) SDSS quasars. We confirmed their lensing nature with additional imaging and spectroscopic observations. The new systems are SDSS J0819+5356 (source redshift z{sub s} = 2.237, lens redshift z{sub l} = 0.294, and image separation {theta} = 4.04 inch), SDSS J1254+2235 (z{sub s} = 3.626, {theta} = 1.56 inch), SDSS J1258+1657 (z{sub s} = 2.702, {theta} = 1.28 inch), SDSS J1339+1310 (z{sub s} = 2.243, {theta} = 1.69 cin), and SDSS J1400+3134 (z{sub s} = 3.317, {theta} = 1.74 inch). We estimate the lens redshifts of the latter four systems to be z{sub l} = 0.4-0.6 from the colors and magnitudes of the lensing galaxies. We find that the image configurations of all systems are well reproduced by standard mass models. Although these lenses will not be included in our statistical sample of z{sub s} < 2.2 lenses, they expand the number of lensed quasars which can be used for high-redshift galaxy and quasar studies.

  5. Selection Effects in the Study of High-Redshift Galaxy Morphology

    Science.gov (United States)

    Elmegreen, Debra M.; Elmegreen, B.

    2010-05-01

    Selection effects from bandshifting, angular resolution limitations, surface brightness dimming, and intergalactic absorption skew our view of high redshift galaxies so that we primarily see those that are extremely bright, massive, and star-bursting. Bandshifting shows a galaxy in its restframe NUV or FUV at z>1, and also biases the determination of age from BViz colors to lower values. The rapid increase in resolvable physical size with redshift for zUDF) noise by redshift z 2. Intergalactic absorption further decreases the brightness of galaxies by factors of a few at this z. These effects combine to make the average star formation rate in an observable clump increase as (1+z)8 for z<1. None of these selection effects directly causes the clump mass to increase with redshift in clumpy galaxies, however. Clumps are well separated from each other and they show up over a wide range of wavelengths. The increase in clump mass with redshift is mostly from an increase in observable galaxy mass. This is because there is a nearly constant ratio of clump mass to galaxy luminosity and the primary selection effect is for bright galaxies, considering that the intrinsic surface brightness for anything observable increases sharply with z. Redshifted versions of local grand design, multiple arm, and flocculent spiral galaxies, along with dwarf irregulars and interacting galaxies, will be shown to indicate which features are observable at high redshift.

  6. The High-redshift Clusters Occupied by Bent Radio AGN (COBRA) Survey: The Spitzer Catalog

    Science.gov (United States)

    Paterno-Mahler, R.; Blanton, E. L.; Brodwin, M.; Ashby, M. L. N.; Golden-Marx, E.; Decker, B.; Wing, J. D.; Anand, G.

    2017-07-01

    We present 190 galaxy cluster candidates (most at high redshift) based on galaxy overdensity measurements in the Spitzer/IRAC imaging of the fields surrounding 646 bent, double-lobed radio sources drawn from the Clusters Occupied by Bent Radio AGN (COBRA) Survey. The COBRA sources were chosen as objects in the Very Large Array FIRST survey that lack optical counterparts in the Sloan Digital Sky Survey to a limit of m r = 22, making them likely to lie at high redshift. This is confirmed by our observations: the redshift distribution of COBRA sources with estimated redshifts peaks near z = 1 and extends out to z≈ 3. Cluster candidates were identified by comparing our target fields to a background field and searching for statistically significant (≥slant 2σ ) excesses in the galaxy number counts surrounding the radio sources; 190 fields satisfy the ≥slant 2σ limit. We find that 530 fields (82.0%) have a net positive excess of galaxies surrounding the radio source. Many of the fields with positive excesses but below the 2σ cutoff are likely to be galaxy groups. Forty-one COBRA sources are quasars with known spectroscopic redshifts, which may be tracers of some of the most distant clusters known.

  7. Feeding cosmic star formation: exploring high-redshift molecular gas with CO intensity mapping

    Science.gov (United States)

    Breysse, Patrick C.; Rahman, Mubdi

    2017-06-01

    The study of molecular gas is crucial for understanding star formation, feedback and the broader ecosystem of a galaxy as a whole. However, we have limited understanding of its physics and distribution in all but the nearest galaxies. We present a new technique for studying the composition and distribution of molecular gas in high-redshift galaxies inaccessible to existing methods. Our proposed approach is an extension of carbon monoxide intensity mapping methods, which have garnered significant experimental interest in recent years. These intensity mapping surveys target the 115 GHz 12CO (1-0) line, but also contain emission from the substantially fainter 110 GHz 13CO (1-0) transition. The method leverages the information contained in the 13CO line by cross-correlating pairs of frequency channels in an intensity mapping survey. Since 13CO is emitted from the same medium as the 12CO, but saturates at a much higher column density, this cross-correlation provides valuable information about both the gas density distribution and isotopologue ratio, inaccessible from the 12CO alone. Using a simple model of these molecular emission lines, we show that a future intensity mapping survey can constrain the abundance ratio of these two species and the fraction of emission from optically thick regions to order ˜30 per cent. These measurements cannot be made by traditional CO observations, and consequently the proposed method will provide unique insight into the physics of star formation, feedback and galactic ecology at high redshifts.

  8. Quantitative Morphology of High-Redshift Galaxies Using GALEX Ultraviolet Images of Nearby Galaxies

    Directory of Open Access Journals (Sweden)

    Bum-Suk Yeom

    2017-09-01

    Full Text Available We present simulations of the optical-band images of high-redshift galaxies utilizing 845 near-ultraviolet (NUV images of nearby galaxies obtained through the Galaxy Evolution Explorer (GALEX. We compute the concentration (C, asymmetry (A, Gini (G, and M20 parameters of the GALEX NUV/Sloan Digital Sky Survey r-band images at z ~ 0 and their artificially redshifted optical images at z = 0.9 and 1.6 in order to quantify the morphology of galaxies at local and high redshifts. The morphological properties of nearby galaxies in the NUV are presented using a combination of morphological parameters, in which earlytype galaxies are well separated from late-type galaxies in the G–M20, C–M20, A–C, and A–M20 planes. Based on the distribution of galaxies in the A–C and G–M20 planes, we examine the morphological K-correction (i.e., cosmological distance effect and bandshift effect. The cosmological distance effect on the quantitative morphological parameters is found to be significant for early-type galaxies, while late-type galaxies are more greatly affected by the bandshift effect. Knowledge of the morphological K-correction will set the foundation for forthcoming studies on understanding the quantitative assessment of galaxy evolution.

  9. AWAKENING OF THE HIGH-REDSHIFT BLAZAR CGRaBS J0809+5341

    Energy Technology Data Exchange (ETDEWEB)

    Paliya, Vaidehi S.; Stalin, C. S. [Indian Institute of Astrophysics, Block II, Koramangala, Bangalore 560034 (India); Parker, M. L.; Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Ramya, S. [Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai 200030 (China); Covino, S.; Tagliaferri, G. [INAF-Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate (Italy); Sahayanathan, S. [Astrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Ravikumar, C. D., E-mail: vaidehi@iiap.res.in [Department of Physics, University of Calicut, Malappuram 673635 (India)

    2015-04-20

    CGRaBS J0809+5341, a high-redshift blazar at z = 2.144, underwent a giant optical outburst on 2014 April 19 when it brightened by ∼5 mag and reached an unfiltered apparent magnitude of 15.7 mag. This implies an absolute magnitude of −30.5 mag, making it one of the brightest quasars in the universe. This optical flaring triggered us to carry out observations during the decaying part of the flare covering a wide energy range using the Nuclear Spectroscopic Telescope Array, Swift, and ground-based optical facilities. For the first time, the source is detected in γ-rays by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. A high optical polarization of ∼10% is also observed. Using the Sloan Digital Sky Survey spectrum, the accretion disk luminosity and black hole mass are estimated as 1.5 × 10{sup 45} erg s{sup −1} and 10{sup 8.4} M{sub ⊙}, respectively. Using a single zone leptonic emission model, we reproduce the spectral energy distribution of the source during the flaring activity. This analysis suggests that the emission region is probably located outside the broad-line region, and the jet becomes radiatively efficient. We also show that the overall properties of CGRaBS J0809+5341 seem to not be in agreement with the general properties observed in high-redshift blazars up to now.

  10. Awakening of The High-Redshift Blazar CGRaBS J0809+5341

    Science.gov (United States)

    Paliya, Vaidehi S.; Parker, M. L.; Stalin, C. S.; Fabian, A. C.; Ramya, S.; Covino, S.; Tagliaferri, G.; Sahayanathan, S.; Ravikumar, C. D.

    2015-04-01

    CGRaBS J0809+5341, a high-redshift blazar at z = 2.144, underwent a giant optical outburst on 2014 April 19 when it brightened by ˜5 mag and reached an unfiltered apparent magnitude of 15.7 mag. This implies an absolute magnitude of -30.5 mag, making it one of the brightest quasars in the universe. This optical flaring triggered us to carry out observations during the decaying part of the flare covering a wide energy range using the Nuclear Spectroscopic Telescope Array, Swift, and ground-based optical facilities. For the first time, the source is detected in γ-rays by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. A high optical polarization of ˜10% is also observed. Using the Sloan Digital Sky Survey spectrum, the accretion disk luminosity and black hole mass are estimated as 1.5 × 1045 erg s-1 and 108.4 M⊙, respectively. Using a single zone leptonic emission model, we reproduce the spectral energy distribution of the source during the flaring activity. This analysis suggests that the emission region is probably located outside the broad-line region, and the jet becomes radiatively efficient. We also show that the overall properties of CGRaBS J0809+5341 seem to not be in agreement with the general properties observed in high-redshift blazars up to now.

  11. Shocks and Cool Cores: An ALMA View of Massive Galaxy Cluster Formation at High Redshifts

    Science.gov (United States)

    Basu, Kaustuv

    2017-07-01

    These slides present some recent results on the Sunyaev-Zel'dovich (SZ) effect imaging of galaxy cluster substructures. The advantage of SZ imaging at high redshifts or in the low density cluster outskirts is already well-known. Now with ALMA a combination of superior angular resolution and high sensitivity is available. One example is the first ALMA measurement of a merger shock at z=0.9 in the famous El Gordo galaxy cluster. Here comparison between SZ, X-ray and radio data enabled us to put constraints on the shock Mach number and magnetic field strength for a high-z radio relic. Second example is the ALMA SZ imaging of the core region of z=1.4 galaxy cluster XMMU J2235.2-2557. Here ALMA data provide an accurate measurement of the thermal pressure near the cluster center, and from a joint SZ/X-ray analysis we find clear evidence for a reduced core temperature. This result indicate that a cool core establishes itself early enough in the cluster formation history while the gas accumulation is still continuing. The above two ALMA measurements are among several other recent SZ results that shed light on the formation process of massive clusters at high redshifts.

  12. VizieR Online Data Catalog: VANDELS High-Redshift Galaxy Evolution (McLure+, 2017)

    Science.gov (United States)

    McLure, R.; Pentericci, L.; Vandels Team

    2017-11-01

    This is the first data release (DR1) of the VANDELS survey, an ESO public spectroscopy survey targeting the high-redshift Universe. The VANDELS survey uses the VIMOS spectrograph on ESO's VLT to obtain ultra-deep, medium resolution, optical spectra of galaxies within the UKIDSS Ultra Deep Survey (UDS) and Chandra Deep Field South (CDFS) survey fields (0.2 sq. degree total area). Using robust photometric redshift pre-selection, VANDELS is targeting ~2100 galaxies in the redshift interval 1.0=3. In addition, VANDELS is targeting a substantial number of passive galaxies in the redshift interval 1.0survey is obtaining ultra-deep optical spectroscopy with the VIMOS MR grism and GG475 order-sorting filter, which covers the wavelength range 4800-10000Å at a dispersion of 2.5Å/pix and a spectral resolution of R~600. Each galaxy receives between a minimum of 20-hours and a maximum of 80-hours of on-source integration time. The fundamental aim of the survey is to provide the high signal-to-noise spectra necessary to measure key physical properties such as stellar population ages, metallicities and outflow velocities from detailed absorption-line studies. By targeting two extra-galactic survey fields with superb multi-wavelength imaging data, VANDELS is designed to produce a unique legacy dataset for exploring the physics underpinning high-redshift galaxy evolution. (2 data files).

  13. Near-Infrared Follow-up of High Redshift X-ray Clusters

    Science.gov (United States)

    Barkhouse, Wayne; Green, Paul; Vikhlinin, Alexey; Kim, Dong-Woo

    2005-08-01

    Clusters of galaxies provide an intimate view of galaxy evolution over a wide range in cosmic look-back time and environment. From a large Chandra/NOAO serendipitous survey, we have culled a high- confidence list of high redshift cluster candidates to facilitate the investigation of galaxy cluster evolution and provide strong constraints on cosmological parameters. We propose to use FLAMINGOS on the KPNO 4-m telescope to obtain deep near-IR imaging in the J- and K_s-band of 6 extended X-ray sources discovered serendipitously in Chandra images, but undetected in deep 4m/MOSAIC imaging. Our FLAMINGOS observations will measure cluster redshifts (out to z~ 1.5) using the location of the cluster red-sequence in the color-magnitude plane. Cluster attributes, such as the luminosity function, richness, color-magnitude relation, and correlations between near-IR and X-ray properties, will be measured and contrasted with our more local serendipitous sample. These observations promise to substantially increase the number of known high redshift galaxy clusters.

  14. Investigating The Kinematics of Canids and Felids

    Science.gov (United States)

    Sur, D.

    2016-12-01

    For all organisms, metabolic energy is critical for survival. While moving efficiently is a necessity for large carnivores, the influence of kinematics on energy demand remains poorly understood. We measured the kinematics of dogs, wolves, and pumas to detect any differences in their respective energy expenditures. Using 22 kinematic parameters measured on 78 videos, we used one-way ANOVAs and paired T-tests to compare 5 experimental treatments among gaits in dogs (n=11 in 3 breed groups), wolves (n=2), and pumas (n=2). Across the measured parameters, we found greater kinematic similarity than expected among dog breeds and no trend in any of the 22 parameters regarding the effect of steepness on locomotion mechanics. Similarly, treadmill kinematics were nearly identical to those measured during outdoor movement. However, in 3 inches of snow, we observed significant differences (pwolf. When comparing canids (wolves and dogs) to a felid (pumas), we found that pumas and dogs are the most kinematically distinct (differing in 13 of 22 parameters, compared with 5 of 22 for wolves and pumas). Lastly, compared with wolves, walking pumas had larger head angles (p=0.0025), forelimb excursion angles (p=0.0045), and hindlimb excursion angles (p=0.0327). After comparing the energetics of pumas and dogs with their respective kinematics, we noted that less dynamic kinematics result in energy savings. Through tracking the locations and gait behavior of large carnivores, novel sensor technology can reveal how indoor kinematics applies to wild animals and improve the conservation of these species.

  15. The impact of star formation and gamma-ray burst rates at high redshift on cosmic chemical evolution and reionization

    Science.gov (United States)

    Vangioni, Elisabeth; Olive, Keith A.; Prestegard, Tanner; Silk, Joseph; Petitjean, Patrick; Mandic, Vuk

    2015-03-01

    Recent observations in the total luminosity density have led to significant progress in establishing the star formation rate (SFR) at high redshift. Concurrently observed gamma-ray burst rates have also been used to extract the SFR at high redshift. The SFR in turn can be used to make a host of predictions concerning the ionization history of the Universe, the chemical abundances, and supernova rates. We compare the predictions made using a hierarchical model of cosmic chemical evolution based on three recently proposed SFRs: two based on extracting the SFR from the observed gamma-ray burst rate at high redshift, and one based on the observed galaxy luminosity function at high redshift. Using the WMAP/Planck data on the optical depth and epoch of reionization, we find that only the SFR inferred from gamma-ray burst data at high redshift suffices to allow a single mode (in the initial mass function - IMF) of star formation which extends from z = 0 to redshifts >10. For the case of the SFR based on the observed galaxy luminosity function, the reionization history of the Universe requires a bimodal IMF which includes at least a coeval high- (or intermediate-) mass mode of star formation at high redshift (z > 10). Therefore, we also consider here a more general bimodal case which includes an early-forming high-mass mode as a fourth model to test the chemical history of the Universe. We conclude that observational constraints on the global metallicity and optical depth at high redshift favour unseen faint but active star-forming galaxies as pointed out in many recent studies.

  16. Planck intermediate results. XXXIX. The Planck list of high-redshift source candidates

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Burigana, C.; Butler, R. C.; Calabrese, E.; Catalano, A.; Chiang, H. C.; Christensen, P. R.; Clements, D. L.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Dickinson, C.; Diego, J. M.; Dole, H.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Finelli, F.; Flores-Cacho, I.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Harrison, D. L.; Helou, G.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leonardi, R.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Melchiorri, A.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Nati, F.; Natoli, P.; Nesvadba, N. P. H.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Pagano, L.; Pajot, F.; Paoletti, D.; Partridge, B.; Pasian, F.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Pettorino, V.; Piacentini, F.; Piat, M.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Türler, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, F.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Welikala, N.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-12-01

    The Planck mission, thanks to its large frequency range and all-sky coverage, has a unique potential for systematically detecting the brightest, and rarest, submillimetre sources on the sky, including distant objects in the high-redshift Universe traced by their dust emission. A novel method, based on a component-separation procedure using a combination of Planck and IRAS data, has been validated and characterized on numerous simulations, and applied to select the most luminous cold submillimetre sources with spectral energy distributions peaking between 353 and 857 GHz at 5' resolution. A total of 2151 Planck high-z source candidates (the PHZ) have been detected in the cleanest 26% of the sky, with flux density at 545 GHz above 500 mJy. Embedded in the cosmic infrared background close to the confusion limit, these high-z candidates exhibit colder colours than their surroundings, consistent with redshifts z > 2, assuming a dust temperature of Txgal = 35 K and a spectral index of βxgal = 1.5. Exhibiting extremely high luminosities, larger than 1014L⊙, the PHZ objects may be made of multiple galaxies or clumps at high redshift, as suggested by a first statistical analysis based on a comparison with number count models. Furthermore, first follow-up observations obtained from optical to submillimetre wavelengths, which can be found in companion papers, have confirmed that this list consists of two distinct populations. A small fraction (around 3%) of the sources have been identified as strongly gravitationally lensed star-forming galaxies at redshift 2 to 4, while the vast majority of the PHZ sources appear as overdensities of dusty star-forming galaxies, having colours consistent with being at z > 2, and may be considered as proto-cluster candidates. The PHZ provides an original sample, which is complementary to the Planck Sunyaev-Zeldovich Catalogue (PSZ2); by extending the population of virialized massive galaxy clusters detected below z 1.5, the PHZ may contain

  17. High-Redshift Type Ia Supernova Rates in Galaxy Cluster and Field Environments

    Science.gov (United States)

    Barbary, Kyle Harris

    This thesis presents Type Ia supernova (SN Ia) rates from the Hubble Space Telescope (HST) Cluster Supernova Survey, a program designed to efficiently detect and observe high-redshift supernovae by targeting massive galaxy clusters at redshifts 0.9 z z > 0.9 SNe. The SN Ia rate is found to be 0.50+0.23-0.19 (stat) +0.10-0.09 (sys) h 702 SNuB (SNuB = 10-12 SNe Lsun,B-1 yr-1), or in units of stellar mass, 0.36+0.16-0.13 (stat) +0.07-0.06 (sys) h 702 SNuM (SNuM = 10-12 SNe M sun-1 yr-1). This represents a factor of approximately 5 +/- 2 increase over measurements of the cluster rate at z influence of younger stellar populations the rate is also calculated specifically in cluster red-sequence galaxies and in morphologically early-type galaxies, with results similar to the full cluster rate. Finally, the upper limit of one host-less cluster SN Ia detected in the survey implies that the fraction of stars in the intra-cluster medium is less than 0.47 (95% confidence), consistent with measurements at lower redshifts. The volumetric SN Ia rate can also be used to constrain the SN Ia delay time distribution. However, there have been discrepancies in recent analyses of both the high-redshift rate and its implications for the delay time distribution. Here, the volumetric SN Ia rate out to z ˜ 1.6 is measured, based on ˜12 SNe Ia in the foregrounds and backgrounds of the clusters targeted in the survey. The rate is measured in four broad redshift bins. The results are consistent with previous measurements at z > 1 and strengthen the case for a SN Ia rate that is greater than approximately 0.6 x 10-4 h70 3 yr-1 Mpc-3 at z ˜ 1 and flattening out at higher redshift. Assumptions about host-galaxy dust extinction used in different high-redshift rate measurements are examined. Different assumptions may account for some of the difference in published results for the z ˜ 1 rate.

  18. VizieR Online Data Catalog: KMOS AGN Survey at High redshift (KASHz) (Harrison+, 2016)

    Science.gov (United States)

    Harrison, C. M.; Alexander, D. M.; Mullaney, J. R.; Stott, J. P.; Swinbank, A. M.; Arumugam, V.; Bauer, F. E.; Bower, R. G.; Bunker, A. J.; Sharples, R. M.

    2016-08-01

    KASHz is designed to ultimately obtain spatially resolved emission-line kinematics of ~(100-200) high-redshift (z~0.6-3.6) AGN. For our target selection we make use of deep X-ray surveys performed in extragalactic fields (COSMOS, see Scoville et al., 2007, Cat. J/ApJS/171/1; CDF-S, see Giacconi et al. 2001ApJ...551..624G and Xue et al., 2011, Cat. J/ApJS/195/10 (CDFS); UDS, SXDS: see Furusawa et al. 2008, Cat. J/ApJS/176/1 (UDS) and SSA22, see Steidel et al. 1998ApJ...492..428S). (1 data file).

  19. Infrared-faint radio sources in the SERVS deep fields. Pinpointing AGNs at high redshift

    Science.gov (United States)

    Maini, A.; Prandoni, I.; Norris, R. P.; Spitler, L. R.; Mignano, A.; Lacy, M.; Morganti, R.

    2016-12-01

    Context. Infrared-faint radio sources (IFRS) represent an unexpected class of objects which are relatively bright at radio wavelength, but unusually faint at infrared (IR) and optical wavelengths. A recent and extensive campaign on the radio-brightest IFRSs (S1.4 GHz≳ 10 mJy) has provided evidence that most of them (if not all) contain an active galactic nuclei (AGN). Still uncertain is the nature of the radio-faintest IFRSs (S1.4 GHz≲ 1 mJy). Aims: The scope of this paper is to assess the nature of the radio-faintest IFRSs, testing their classification and improving the knowledge of their IR properties by making use of the most sensitive IR survey available so far: the Spitzer Extragalactic Representative Volume Survey (SERVS). We also explore how the criteria of IFRSs can be fine-tuned to pinpoint radio-loud AGNs at very high redshift (z > 4). Methods: We analysed a number of IFRS samples identified in SERVS fields, including a new sample (21 sources) extracted from the Lockman Hole. 3.6 and 4.5 μm IR counterparts of the 64 sources located in the SERVS fields were searched for and, when detected, their IR properties were studied. Results: We compared the radio/IR properties of the IR-detected IFRSs with those expected for a number of known classes of objects. We found that IR-detected IFRSs are mostly consistent with a mixture of high-redshift (z ≳ 3) radio-loud AGNs. The faintest ones (S1.4 GHz 100 μJy), however, could be also associated with nearer (z 2) dust-enshrouded star-burst galaxies. We also argue that, while IFRSs with radio-to-IR ratios >500 can very efficiently pinpoint radio-loud AGNs at redshift 2 < z < 4, lower radio-to-IR ratios ( 100-200) are expected for higher redshift radio-loud AGNs.

  20. A new method to search for high-redshift clusters using photometric redshifts

    Energy Technology Data Exchange (ETDEWEB)

    Castignani, G.; Celotti, A. [SISSA, Via Bonomea 265, I-34136 Trieste (Italy); Chiaberge, M.; Norman, C., E-mail: castigna@sissa.it [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2014-09-10

    We describe a new method (Poisson probability method, PPM) to search for high-redshift galaxy clusters and groups by using photometric redshift information and galaxy number counts. The method relies on Poisson statistics and is primarily introduced to search for megaparsec-scale environments around a specific beacon. The PPM is tailored to both the properties of the FR I radio galaxies in the Chiaberge et al. sample, which are selected within the COSMOS survey, and to the specific data set used. We test the efficiency of our method of searching for cluster candidates against simulations. Two different approaches are adopted. (1) We use two z ∼ 1 X-ray detected cluster candidates found in the COSMOS survey and we shift them to higher redshift up to z = 2. We find that the PPM detects the cluster candidates up to z = 1.5, and it correctly estimates both the redshift and size of the two clusters. (2) We simulate spherically symmetric clusters of different size and richness, and we locate them at different redshifts (i.e., z = 1.0, 1.5, and 2.0) in the COSMOS field. We find that the PPM detects the simulated clusters within the considered redshift range with a statistical 1σ redshift accuracy of ∼0.05. The PPM is an efficient alternative method for high-redshift cluster searches that may also be applied to both present and future wide field surveys such as SDSS Stripe 82, LSST, and Euclid. Accurate photometric redshifts and a survey depth similar or better than that of COSMOS (e.g., I < 25) are required.

  1. COSMIC RAYS CAN DRIVE STRONG OUTFLOWS FROM GAS-RICH HIGH-REDSHIFT DISK GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Hanasz, M.; Kowalik, K.; Wóltański, D. [Centre for Astronomy, Nicolaus Copernicus University, Faculty of Physics, Astronomy and Informatics, Grudziadzka 5, PL-87100 Toruń (Poland); Lesch, H. [Universitäts-Sternwarte München, Scheinerstr. 1, D-81679 München (Germany); Naab, T. [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85741 Garching bei München (Germany); Gawryszczak, A., E-mail: mhanasz@astri.uni.torun.pl [Poznań Supercomputing and Networking Centre, ul. Noskowskiego 10, PL-61-704 Poznań (Poland)

    2013-11-10

    We present simulations of the magnetized interstellar medium (ISM) in models of massive star-forming (40 M {sub ☉} yr{sup –1}) disk galaxies with high gas surface densities (Σ{sub gas} ∼ 100 M {sub ☉} pc{sup –2}) similar to observed star-forming high-redshift disks. We assume that type II supernovae deposit 10% of their energy into the ISM as cosmic rays (CRs) and neglect the additional deposition of thermal energy or momentum. With a typical Galactic diffusion coefficient for CRs (3 × 10{sup 28} cm{sup 2} s{sup –1}), we demonstrate that this process alone can trigger the local formation of a strong low-density galactic wind maintaining vertically open field lines. Driven by the additional pressure gradient of the relativistic fluid, the wind speed can exceed 10{sup 3} km s{sup –1}, much higher than the escape velocity of the galaxy. The global mass loading, i.e., the ratio of the gas mass leaving the galactic disk in a wind to the star formation rate, becomes of order unity once the system has settled into an equilibrium. We conclude that relativistic particles accelerated in supernova remnants alone provide a natural and efficient mechanism to trigger winds similar to observed mass-loaded galactic winds in high-redshift galaxies. These winds also help in explaining the low efficiencies for the conversion of gas into stars in galaxies, as well as the early enrichment of the intergalactic medium with metals. This mechanism may be at least of similar importance to the traditionally considered momentum feedback from massive stars and thermal and kinetic feedback from supernova explosions.

  2. Gemini Spectroscopy of Supernovae from the Supernova Legacy Survey: Improving High-Redshift Supernova Selection and Classification

    Science.gov (United States)

    Howell, D. A.; Sullivan, M.; Perrett, K.; Bronder, T. J.; Hook, I. M.; Astier, P.; Aubourg, E.; Balam, D.; Basa, S.; Carlberg, R. G.; Fabbro, S.; Fouchez, D.; Guy, J.; Lafoux, H.; Neill, J. D.; Pain, R.; Palanque-Delabrouille, N.; Pritchet, C. J.; Regnault, N.; Rich, J.; Taillet, R.; Knop, R.; McMahon, R. G.; Perlmutter, S.; Walton, N. A.

    2005-12-01

    We present new techniques for improving the efficiency of supernova (SN) classification at high redshift using 64 candidates observed at Gemini North and South during the first year of the Supernova Legacy Survey (SNLS). The SNLS is an ongoing 5 year project with the goal of measuring the equation of state of dark energy by discovering and following over 700 high-redshift SNe Ia using data from the Canada-France-Hawaii Telescope Legacy Survey. We achieve an improvement in the SN Ia spectroscopic confirmation rate: at Gemini 71% of candidates are now confirmed as SNe Ia, compared to 54% using the methods of previous surveys. This is despite the comparatively high redshift of this sample, in which the median SN Ia redshift is z=0.81 (0.155Berthelot, 75231 Paris Cedex 05, France. DSM/DAPNIA, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France.

  3. The [CII] 158 μm line emission in high-redshift galaxies

    Science.gov (United States)

    Lagache, G.; Cousin, M.; Chatzikos, M.

    2018-02-01

    Gas is a crucial component of galaxies, providing the fuel to form stars, and it is impossible to understand the evolution of galaxies without knowing their gas properties. The [CII] fine structure transition at 158 μm is the dominant cooling line of cool interstellar gas, and is the brightest of emission lines from star forming galaxies from FIR through metre wavelengths, almost unaffected by attenuation. With the advent of ALMA and NOEMA, capable of detecting [CII]-line emission in high-redshift galaxies, there has been a growing interest in using the [CII] line as a probe of the physical conditions of the gas in galaxies, and as a star formation rate (SFR) indicator at z ≥ 4. In this paper, we have used a semi-analytical model of galaxy evolution (G.A.S.) combined with the photoionisation code CLOUDY to predict the [CII] luminosity of a large number of galaxies (25 000 at z ≃ 5) at 4 ≤ z ≤ 8. We assumed that the [CII]-line emission originates from photo-dominated regions. At such high redshift, the CMB represents a strong background and we discuss its effects on the luminosity of the [CII] line. We studied the L[CII ]-SFR and L[ CII ]-Zg relations and show that they do not strongly evolve with redshift from z = 4 and to z = 8. Galaxies with higher [CII] luminosities tend to have higher metallicities and higher SFRs but the correlations are very broad, with a scatter of about 0.5 and 0.8 dex for L[ CII ]-SFR and L[ CII ]-Zg, respectively. Our model reproduces the L[ CII ]-SFR relations observed in high-redshift star-forming galaxies, with [CII] luminosities lower than expected from local L[ CII ]-SFR relations. Accordingly, the local observed L[ CII ]-SFR relation does not apply at high-z (z ≳ 5), even when CMB effects are ignored. Our model naturally produces the [CII] deficit (i.e. the decrease of L[ CII ]/LIR with LIR), which appears to be strongly correlated with the intensity of the radiation field in our simulated galaxies. We then predict the

  4. Investigating the Local and High Redshift Universe With Deep Survey Data and Ground-Based Spectroscopy

    Science.gov (United States)

    Masters, Daniel Charles

    Large multiwavelength surveys are now driving the frontiers of astronomical research. I describe results from my work using data from two large astronomical surveys: the Cosmic Evolution Survey (COSMOS), which has obtained deep photometric and spectroscopic data on two square degrees of the sky using many of the most powerful telescopes in the world, and the WFC3 Infrared Spectroscopic Parallels (WISP) Survey, which uses the highly sensitive slitless spectroscopic capability of the Hubble Space Telescope Wide Field Camera 3 to detect star-forming galaxies over most of the universe's history. First I describe my work on the evolution of the high-redshift quasar luminosity function, an important observational quantity constraining the growth of the supermassive black holes in the early universe. I show that the number density of faint quasars declines rapidly above z ˜ 3. This result is discussed in the context of cosmic reionization and the coevolution of galaxies and their central black holes. Next I present results of a multi-year campaign of near-infrared spectroscopy with FIRE, a world-class near-infrared spectrometer on the Magellan Baade 6.5 meter telescope in Chile, targeting emission-line galaxies at z ˜ 2 discovered with the Hubble Space Telescope. Our results showed that the typical emission-line galaxy at this redshift has low-metallicity, low dust obscuration, high ionization parameter, and little evidence for significant active galactic nucleus (AGN) contribution to the emission lines. We also find evidence that high redshift star-forming galaxies have enhanced nitrogen abundances. This result has interesting implications for the nature of the star formation in such galaxies -- in particular, it could mean that a large fraction of such galaxies harbor substantial populations of Wolf-Rayet stars, which are massive, evolved stars ejecting large amounts of enriched matter into the interstellar medium. Finally, I will discuss the discovery of three

  5. The Clustering of High-Redshift (2.9 < z < 5.4) Quasars in SDSS Stripe 82

    Science.gov (United States)

    Timlin, John; Ross, Nicolas; Richards, Gordon; Myers, Adam; Bauer, Franz Erik; Lacy, Mark; Schneider, Donald; Wollack, Edward; Zakamska, Nadia

    2018-01-01

    We present the data from the Spitzer IRAC Equatorial Survey (SpIES) along with our first high-redshift (2.9SpIES is a mid-infrared survey covering ~100 square degrees of the Sloan Digital Sky Survey (SDSS) Stripe 82 (S82) field. The SpIES field is optimally located to overlap with the optical data from SDSS and to complement the area of the pre-existing Spitzer data from the Spitzer-HETDEX Exploratory Large-area (SHELA) survey, which adds ~20 square degrees of infrared coverage on S82. SpIES probes magnitudes significantly fainter than WISE; depth that is crucial to detect faint, high-redshift quasars. Using the infrared data from SpIES and SHELA, and the deep optical data from SDSS, we employ multi-dimensional empirical selection algorithms to identify high-redshift quasar candidates in this field. We then combine these candidates with spectroscopically confirmed high-redshift quasars and measure the angular correlation function. Using these results, we compute the linear bias to try to constrain quasar feedback models akin to those in Hopkins et al. 2007.

  6. Overdensities of SMGs around WISE-selected, ultraluminous, high-redshift AGNs

    Science.gov (United States)

    Jones, Suzy F.; Blain, Andrew W.; Assef, Roberto J.; Eisenhardt, Peter; Lonsdale, Carol; Condon, James; Farrah, Duncan; Tsai, Chao-Wei; Bridge, Carrie; Wu, Jingwen; Wright, Edward L.; Jarrett, Tom

    2017-08-01

    We investigate extremely luminous dusty galaxies in the environments around Wide-field Infrared Survey Explorer (WISE)-selected hot dust-obscured galaxies (Hot DOGs) and WISE/radio-selected active galactic nuclei (AGNs) at average redshifts of z = 2.7 and 1.7, respectively. Previous observations have detected overdensities of companion submillimetre-selected sources around 10 Hot DOGs and 30 WISE/radio AGNs, with overdensities of ˜2-3 and ˜5-6, respectively. We find that the space densities in both samples to be overdense compared to normal star-forming galaxies and submillimetre galaxies (SMGs) in the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) Cosmology Legacy Survey (S2CLS). Both samples of companion sources have consistent mid-infrared (mid-IR) colours and mid-IR to submm ratios as SMGs. The brighter population around WISE/radio AGNs could be responsible for the higher overdensity reported. We also find that the star formation rate densities are higher than the field, but consistent with clusters of dusty galaxies. WISE-selected AGNs appear to be good signposts for protoclusters at high redshift on arcmin scales. The results reported here provide an upper limit to the strength of angular clustering using the two-point correlation function. Monte Carlo simulations show no angular correlation, which could indicate protoclusters on scales larger than the SCUBA-2 1.5-arcmin scale maps.

  7. Dynamical dark energy simulations: high accuracy power spectra at high redshift

    Energy Technology Data Exchange (ETDEWEB)

    Casarini, Luciano; Bonometto, Silvio A. [Department of Physics G. Occhialini-Milano-Bicocca University, Piazza della Scienza 3, 20126 Milano (Italy); Maccio, Andrea V., E-mail: luciano.casarini@mib.infn.it, E-mail: maccio@mpia.de, E-mail: silvio.bonometto@mib.infn.it [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany)

    2009-03-15

    Accurate predictions on non-linear power spectra, at various redshift z, will be a basic tool to interpret cosmological data from next generation mass probes, so obtaining key information on Dark Energy nature. This calls for high precision simulations, covering the whole functional space of w(z) state equations and taking also into account the admitted ranges of other cosmological parameters; surely a difficult task. A procedure was however suggested, able to match the spectra at z = 0, up to k {approx} 3 hMpc{sup -1}, in cosmologies with an (almost) arbitrary w(z), by making recourse to the results of N-body simulations with w = const. In this paper we extend such procedure to high redshift and test our approach through a series of N-body gravitational simulations of various models, including a model closely fitting WMAP5 and complementary data. Our approach detects w = const. models, whose spectra meet the requirement within 1% at z = 0 and perform even better at higher redshift, where they are close to a permil precision. Available Halofit expressions, extended to (constant) w{ne}-1 are unfortunately unsuitable to fit the spectra of the physical models considered here. Their extension to cover the desired range should be however feasible, and this will enable us to match spectra from any DE state equation.

  8. Physical conditions of the interstellar medium in high-redshift submillimetre bright galaxies

    Science.gov (United States)

    Yang, Chentao

    2017-12-01

    The discovery of a population of high- redshift dust-obscured submillimeter galaxies (SMGs) from ground-based submm cameras has revolutionised our understanding of galaxy evolution and star formation in extreme conditions. They are the strongest starbursts in the Universe approaching the Eddington limit and are believed to be the progenitors of the most massive galaxies today. However, theoretical models of galaxy evolution have even been challenged by a large number of detections of high-redshift SMGs. A very few among them are gravitationally lensed by an intervening galaxy. Recent wide-area extragalactic surveys have discovered hundreds of such strongly lensed SMGs, opening new exciting opportunities for observing the interstellar medium in these exceptional objects. We have thus carefully selected a sample of strongly gravitational lensed SMGs based on the submillimeter flux limit from the Herschel-ATLAS sample. Using IRAM telescopes, we have built a rich H2O-line-detected sample of 16 SMGs. We found a close-to-linear tight correlation between the H2O line and total infrared luminosity. This indicates the importance of far-IR pumping to the excitation of the H2O lines. Using a far-IR pumping model, we have derived the physical properties of the H2O gas and the dust. We showed that H2O lines trace a warm dense gas that may be closely related to the active star formation. Along with the H2O lines, several H2O+ lines have also been detected in three of our SMGs. We also find a tight correlation between the luminosity of the lines of H2O and H2O+ from local ULIRGs to high-redshift SMGs. The flux ratio between H2O+ and H2O suggests that cosmic rays from strong star forming activities are possibly driving the related oxygen chemistry. Another important common molecular gas tracer is the CO line. We have observed multiple transitions of the CO lines in each of our SMGs with IRAM 30m telescope. By analysing the CO line profile, we discovered a significant differential

  9. Spectroscopic confirmation of high-redshift supernovae with the ESO VLT

    Energy Technology Data Exchange (ETDEWEB)

    Lidman, C.; Howell, D.A.; Folatelli, G.; Garavini, G.; Nobili, S.; Aldering, G.; Amanullah, R.; Antilogus, P.; Astier, P.; Blanc, G.; Burns, M.S.; Conley, A.; Deustua, S.E.; Doi, M.; Ellis, R.; Fabbro, S.; Fadeyev, V.; Gibbons, R.; Goldhaber, G.; Goobar, A.; Groom, D.E.; Hook, I.; Kashikawa, N.; Kim, A.G.; Knop, R.A.; Lee, B.C.; Mendez, J.; Morokuma, T.; Motohara, K.; Nugent, P.E.; Pain, R.; Perlmutter, S.; Prasad, V.; Quimby, R.; Raux, J.; Regnault, N.; Ruiz-Lapuente, P.; Sainton, G.; Schaefer, B.E.; Schahmaneche, K.; Smith, E.; Spadafora, A.L.; Stanishev, V.; Walton, N.A.; Wang, L.; Wood-Vasey, W.M.; Yasuda,

    2004-10-04

    We present VLT FORS1 and FORS2 spectra of 39 candidate high-redshift supernovae that were discovered as part of a cosmological study using type Ia supernovae (SNe Ia) over a wide range of redshifts. From the spectra alone, 20 candidates are spectrally classified as SNe Ia with redshifts ranging from z = 0.212 to z = 1.181. Of the remaining 19 candidates, 1 might be a type II supernova and 11 exhibit broad supernova-like spectral features and/or have supernova-like light curves. The candidates were discovered in 8 separate ground-based searches. In those searches in which SNe Ia at z {approx} 0.5 were targeted, over 80 percent of the observed candidates were spectrally classified as SNe Ia. In those searches in which SNe Ia with z > 1 were targeted, 4 candidates with z > 1 were spectrally classified as SNe Ia and later followed with ground and space based observatories. We present the spectra of all candidates, including those that could not be spectrally classified as supernova.

  10. Local analogues of high-redshift star-forming galaxies: integral field spectroscopy of green peas

    Science.gov (United States)

    Lofthouse, E. K.; Houghton, R. C. W.; Kaviraj, S.

    2017-10-01

    We use integral field spectroscopy, from the SWIFT and PALM3K instruments, to perform a spatially resolved spectroscopic analysis of four nearby highly star-forming 'green pea' (GP) galaxies, that are likely analogues of high-redshift star-forming systems. By studying emission-line maps in H α, [N II] λλ6548,6584 and [S II] λλ6716,6731, we explore the kinematic morphology of these systems and constrain properties such as gas-phase metallicities, electron densities and gas-ionization mechanisms. Two of our GPs are rotationally supported while the others are dispersion-dominated systems. The rotationally supported galaxies both show evidence for recent or ongoing mergers. However, given that these systems have intact discs, these interactions are likely to have low-mass ratios (I.e. minor mergers), suggesting that the minor-merger process may be partly responsible for the high star formation rates seen in these GPs. Nevertheless, the fact that the other two GPs appear morphologically undisturbed suggests that mergers (including minor mergers) are not necessary for driving the high star formation rates in such galaxies. We show that the GPs are metal-poor systems (25-40 per cent of solar) and that the gas ionization is not driven by active galactic nuclei (AGN) in any of our systems, indicating that the AGN activity is not coeval with star formation in these starbursting galaxies.

  11. The Origin and Evolution of Interstellar Dust in the Local and High-redshift Universe

    Science.gov (United States)

    Dwek, Eliahu

    2012-01-01

    In this talk I will begin by reviewing our current state of knowledge regarding the origin and evolution of dust in the local solar neighborhood. using chemical evolution models, I will discuss their many different input parameters and their uncertainties. An important consequence of these models is the delayed injection of dust from AGB stars, compared to supernova-condensed dust, into the interstellar medium. I will show that these stellar evolutionary effects on dust composition are manifested in the infrared spectra of local galaxies. The delayed production of dust in AGB stars has also important consequences for the origin of the large amount of dust detected in high-redshift galaxies, when the universe was less that approx. 1 Gyr old. Supernovae may have been the only viable dust sources in those galaxies. Recent observations of sN1987a show a significant mass of dust in the ejecta of this SN. Is that production rate high enough to account for the observed dust mass in these galaxies? If not, what are the alternative viable sources of dust, and how do they depend on the nature of the galaxy (starburst or AGN) and its star formation history .

  12. A new method to obtain the broad line region size of high redshift quasars

    Energy Technology Data Exchange (ETDEWEB)

    Negrete, C. Alenka [Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico); Dultzin, Deborah [Instituto de Astronomía, Universidad Nacional Autónoma de México (Mexico); Marziani, Paola [INAF, Astronomical Observatory of Padova (Italy); Sulentic, Jack W., E-mail: cnegrete@inaoep.mx, E-mail: deborah@astro.unam.mx, E-mail: paola.marziani@oapd.inaf.it, E-mail: sulentic@iaa.es [Instituto de Astrofísica de Andalucía (Spain)

    2014-10-10

    We present high signal-to-noise ratio UV spectra for eight quasars at z ∼ 3 obtained with Very Large Telescope/FORS. The spectra enable us to analyze in detail the strong and weak emission features in the rest frame range 1300-2000 Å of each source (C III] λ1909, Si III] λ1892, Al III λ1860, Si II λ1814, C IV λ1549 and blended Si IV λ1397+O IV] λ1402). The flux ratios Al III λ1860/Si III] λ1892, C IV λ1549/Al III λ1860, Si IV λ1397+O IV] λ1402/Si III] λ1892 and Si IV λ1397+O IV] λ1402/C IV λ1549 strongly constrain ionizing photon flux and metallicity through the use of diagnostic maps built from CLOUDY simulations. The radius of the broad line region is then derived from the ionizing photon flux applying the definition of the ionization parameter. The r {sub BLR} estimate and the width of a virial component isolated in prominent UV lines yields an estimate of black hole mass. We compare our results with previous estimates obtained from the r {sub BLR}-luminosity correlation customarily employed to estimate the black hole masses of high redshift quasars.

  13. Can planet formation resolve the dust budget crisis in high-redshift galaxies?

    Science.gov (United States)

    Forgan, D. H.; Rowlands, K.; Gomez, H. L.; Gomez, E. L.; Schofield, S. P.; Dunne, L.; Maddox, S.

    2017-12-01

    The process of planet formation offers a rich source of dust production via grain growth in protostellar discs, and via grinding of larger bodies in debris disc systems. Chemical evolution models, designed to follow the build up of metals and dust in galaxies, do not currently account for planet formation. We consider the possibility that the apparent underprediction of dust mass in high-redshift galaxies by chemical evolution models could be in part, due to these models neglecting this process, specifically due to their assumption that a large fraction of the dust mass is removed from the interstellar medium during star formation (so-called astration). By adding a planet formation phase into galaxy chemical evolution, we demonstrate that the dust budget crisis can be partially ameliorated by a factor of 1.3-1.5 only if (I) circumstellar discs prevent a large fraction of the dust mass entering the star during its birth, and (II) that dust mass is preferentially liberated via jets, winds and outflows rather than accreted into planetary-mass bodies.

  14. Precessing Jet in the High-Redshift Blazar J0017+8135

    Directory of Open Access Journals (Sweden)

    Kristóf Rozgonyi

    2016-08-01

    Full Text Available The prominent flat-spectrum radio quasar J0017+8135 (S5 0014+81 at z = 3.366 is one of the most luminous active galactic nuclei (AGN known. Its milliarcsecond-scale radio jet structure has been studied with very long baseline interferometry (VLBI since the 1980s. The quasar was selected as one of the original defining objects of the International Celestial Reference Frame, but left out from its current second realization (ICRF2 because of systematic long-term positional variations. Here we analyse archival 8.6- and 2.3-GHz VLBI imaging data collected at nearly 100 different epochs during more than 20 years, to obtain information about the kinematics of jet components. Because of the cosmological time dilation, extensive VLBI monitoring data are essential to reveal changes in the jet structure of high-redshift AGN. In the case of J0017+8135, the data can be described with a simple kinematic model of jet precession with a 12-year periodicity in the observer’s frame.

  15. The impact of coupled dark energy cosmologies on the high-redshift intergalactic medium

    Science.gov (United States)

    Baldi, M.; Viel, M.

    2010-11-01

    We present an analysis of high-resolution hydrodynamical N-body simulations of coupled dark energy cosmologies which focuses on the statistical properties of the transmitted Lyman α flux in the high-redshift intergalactic medium (IGM). In these models the growth of the diffuse cosmic web differs from the standard ΛCDM case: the density distribution is skewed towards underdense regions and the matter power spectra are typically larger (in a scale-dependent way). These differences are also appreciable in the Lyman α flux and are larger than 5 per cent (10 per cent) at z = 2-4 in the flux probability distribution function (pdf) for high-transmissivity regions and for values of the coupling parameter β = 0.08 (β = 0.2). The flux power spectrum is also affected at the ~2 per cent (~5-10 per cent) level for β = 0.08 (β = 0.2) in a redshift-dependent way. We infer the behaviour of flux pdf and flux power for a reasonable range of couplings and present constraints using present high- and low-resolution data sets. We find an upper limit β <~ 0.15 (at 2σ confidence level), which is obtained using only IGM data and is competitive with those inferred from other large-scale structure probes.

  16. Mass and metallicity scaling relations of high-redshift star-forming galaxies selected by GRBs

    Science.gov (United States)

    Arabsalmani, M.; Møller, P.; Perley, D. A.; Freudling, W.; Fynbo, J. P. U.; Le Floc'h, E.; Zwaan, M. A.; Schulze, S.; Tanvir, N. R.; Christensen, L.; Levan, A. J.; Jakobsson, P.; Malesani, D.; Cano, Z.; Covino, S.; D'Elia, V.; Goldoni, P.; Gomboc, A.; Heintz, K. E.; Sparre, M.; de Ugarte Postigo, A.; Vergani, S. D.

    2018-01-01

    We present a comprehensive study of the relations between gas kinematics, metallicity and stellar mass in a sample of 82 gamma-ray burst (GRB)-selected galaxies using absorption and emission methods. We find the velocity widths of both emission and absorption profiles to be a proxy of stellar mass. We also investigate the velocity-metallicity correlation and its evolution with redshift. Using 33 GRB hosts with measured stellar mass and metallicity, we study the mass-metallicity relation for GRB host galaxies in a stellar mass range of 108.2-1011.1 M⊙ and a redshift range of z ∼ 0.3-3.4. The GRB-selected galaxies appear to track the mass-metallicity relation of star-forming galaxies but with an offset of 0.15 towards lower metallicities. This offset is comparable with the average error bar on the metallicity measurements of the GRB sample and also the scatter on the mass-metallicity relation of the general population. It is hard to decide whether this relatively small offset is due to systematic effects or the intrinsic nature of GRB hosts. We also investigate the possibility of using absorption-line metallicity measurements of GRB hosts to study the mass-metallicity relation at high redshifts. Our analysis shows that the metallicity measurements from absorption methods can significantly differ from emission metallicities and assuming identical measurements from the two methods may result in erroneous conclusions.

  17. Luminous compact blue galaxies in the local Universe: A key reference for high-redshift studies

    Science.gov (United States)

    Pérez Gallego, J.; Guzmán, R.; Castander, F. J.; Garland, C. A.; Pisano, D. J.

    2005-05-01

    Luminous Compact Blue Galaxies (LCBGs) are high surface brightness starburst galaxies, bluer than a typical Sbc and brighter than ˜0.25Lstar. LCBGs have evolved more than any other galaxy class in the last ˜8 Gyr, and are a major contributor to the observed enhancement of the UV luminosity density of the Universe at z≤1. Despite the key role LCBGs may play in galaxy evolution, their statistical properties are still largely unknown. We have selected a complete sample of ˜25 LCBGs within 100 Mpc, after investigating over 106 nearby galaxies from the DR1 of the SDSS database. This sample, although small, provides an excellent reference for comparison with current and future surveys of similar galaxies at high redshift, including the population of Lyman-break galaxies. We present preliminary results of this study using 3D spectroscopic observations obtained over a very wide range in wavelength, using WIYN/DENSEPAK in the optical, FISICA in the infrared, and the VLA at cm wavelengths.

  18. Herschel And Alma Observations Of The Ism In Massive High-Redshift Galaxy Clusters

    Science.gov (United States)

    Wu, John F.; Aguirre, Paula; Baker, Andrew J.; Devlin, Mark J.; Hilton, Matt; Hughes, John P.; Infante, Leopoldo; Lindner, Robert R.; Sifón, Cristóbal

    2017-06-01

    The Sunyaev-Zel'dovich effect (SZE) can be used to select samples of galaxy clusters that are essentially mass-limited out to arbitrarily high redshifts. I will present results from an investigation of the star formation properties of galaxies in four massive clusters, extending to z 1, which were selected on the basis of their SZE decrements in the Atacama Cosmology Telescope (ACT) survey. All four clusters have been imaged with Herschel/PACS (tracing star formation rate) and two with ALMA (tracing dust and cold gas mass); newly discovered ALMA CO(4-3) and [CI] line detections expand an already large sample of spectroscopically confirmed cluster members. Star formation rate appears to anti-correlate with environmental density, but this trend vanishes after controlling for stellar mass. Elevated star formation and higher CO excitation are seen in "El Gordo," a violent cluster merger, relative to a virialized cluster at a similar high (z 1) redshift. Also exploiting ATCA 2.1 GHz observations to identify radio-loud active galactic nuclei (AGN) in our sample, I will use these data to develop a coherent picture of how environment influences galaxies' ISM properties and evolution in the most massive clusters at early cosmic times.

  19. DUST FORMATION, EVOLUTION, AND OBSCURATION EFFECTS IN THE VERY HIGH-REDSHIFT UNIVERSE

    Energy Technology Data Exchange (ETDEWEB)

    Dwek, Eli; Benford, Dominic J. [Observational Cosmology Lab., Code 665, NASA at Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Staguhn, Johannes; Su, Ting [Also at Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA. (United States); Arendt, Richard G. [Also at CRESST, University of Maryland Baltimore County, Baltimore, MD 21250, USA. (United States); Kovacks, Attila, E-mail: eli.dwek@nasa.gov [Also at Astronomy Department, CalTech, Pasadena, CA 90025, USA. (United States)

    2014-06-20

    The evolution of dust at redshifts z ≳ 9, and consequently the dust properties, differs greatly from that in the local universe. In contrast to the local universe, core collapse supernovae (CCSNe) are the only source of thermally condensed dust. Because of the low initial dust-to-gas mass ratio, grain destruction rates are low, so that CCSNe are net producers of interstellar dust. Galaxies with large initial gas mass or high mass infall rate will therefore have a more rapid net rate of dust production compared to galaxies with lower gas mass, even at the same star formation rate. The dust composition is dominated by silicates, which exhibit a strong rise in the UV opacity near the Lyman break. This ''silicate-UV break'' may be confused with the Lyman break, resulting in a misidentification of a galaxy's photometric redshift. In this Letter we demonstrate these effects by analyzing the spectral energy distribution of MACS1149-JD, a lensed galaxy at z = 9.6. A potential 2 mm counterpart of MACS1149-JD has been identified with GISMO. While additional observations are required to corroborate this identification, we use this possible association to illustrate the physical processes and the observational effects of dust in the very high-redshift universe.

  20. The discovery of high-redshift supernovae and their cosmological implications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Alex G. [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-09-01

    In this thesis the author discusses the methodology for doing photometry from procedure of extracting supernova counts from images that contain combined supernova plus galaxy flux, to standard star calibration, to additional instrumental corrections that arise due to the multiple telescopes used for observations. He discusses the different sources of photometric error and their correlations, and the construction of the covariance matrix for all the points in the light curve. He then describes the K corrections which account for the redshifting of spectra that are necessary to compare the photometry of the high-redshift data with those from nearby (z < 0.1) supernovae. Finally, he uses the first seven of the supernovae to test the hypothesis that they live in an under-dense bubble where the locally measured Hubble constant differs significantly from the true Hubble constant. He also uses the data to place limits on the value of the Hubble constant. Discussions of several other important aspects of the data analysis are or will be included in other papers. These topics include a description of how the covariance matrix is used to generate light-curve fits, a discussion of non-photometric systematic errors that also effect the measurements, and a discussion of the application of the supernovae to address other scientific/cosmological problems.

  1. The XMM-Newton Very Large Program on Cosmology with High-Redshift Quasars

    Science.gov (United States)

    Risaliti, G.

    2017-10-01

    The non-linear relation between the X-ray and UV emission in quasars can be used to estimate the distance of quasars with a precision of 0.2 dex. Based on this property, we built a Hubble Diagram of quasars up to z˜6. This provides a new way to test the cosmological model at high redshift, and to measure the cosmological parameters. So far, we filled the Hubble Diagram with SDSS quasars with serendipitous XMM observation. This is an efficient method up to z˜2-2.5, but at higher redshifts pointed observations are needed in order to constrain the cosmological models. XMM-Newton will observe 30 optically bright quasars at z 3, allowing to measure the expansion rate of the Universe at z=3 with a 8% precision. This will provide a tight test of the standard LCDM model, and an improvement of the constraints on the possible evolution of the equation of state of the dark energy.

  2. Abolition of peroxiredoxin-5 mitochondrial targeting during canid evolution.

    Directory of Open Access Journals (Sweden)

    Valérie Van der Eecken

    Full Text Available In human, the subcellular targeting of peroxiredoxin-5 (PRDX5, a thioredoxin peroxidase, is dependent on the use of multiple alternative transcription start sites and two alternative in-frame translation initiation sites, which determine whether or not the region encoding a mitochondrial targeting sequence (MTS is translated. In the present study, the abolition of PRDX5 mitochondrial targeting in dog is highlighted and the molecular mechanism underlying the loss of mitochondrial PRDX5 during evolution is examined. Here, we show that the absence of mitochondrial PRDX5 is generalized among the extant canids and that the first events leading to PRDX5 MTS abolition in canids involve a mutation in the more 5' translation initiation codon as well as the appearance of a STOP codon. Furthermore, we found that PRDX5 MTS functionality is maintained in giant panda and northern elephant seal, which are phylogenetically closely related to canids. Also, the functional consequences of the restoration of mitochondrial PRDX5 in dog Madin-Darby canine kidney (MDCK cells were investigated. The restoration of PRDX5 mitochondrial targeting in MDCK cells, instead of protecting, provokes deleterious effects following peroxide exposure independently of its peroxidase activity, indicating that mitochondrial PRDX5 gains cytotoxic properties under acute oxidative stress in MDCK cells. Altogether our results show that, although mitochondrial PRDX5 cytoprotective function against oxidative stress has been clearly demonstrated in human and rodents, PRDX5 targeting to mitochondria has been evolutionary lost in canids. Moreover, restoration of mitochondrial PRDX5 in dog MDCK cells, instead of conferring protection against peroxide exposure, makes them more vulnerable.

  3. Clustering of High Redshift (z>2.9) Quasars from the Sloan Digital Sky Survey

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yue; Strauss, Michael A.; Oguri, Masamune; Hennawi, Joseph F.; Fan, Xiaohui; Richards, Gordon T.; Hall, Patrick B.; Schneider, Donald P.; Szalay, Alexander S.; Thakar, Anirudda R.; Berk, Daniel E.Vanden; Anderson, Scott F.; Bahcall, Neta A.; /KIPAC, Menlo Park

    2006-11-30

    We study the two-point correlation function of a uniformly selected sample of 4,428 optically selected luminous quasars with redshift 2.9 {le} z {le} 5.4 selected over 4041 deg{sup 2} from the Fifth Data Release of the Sloan Digital Sky Survey. We fit a power-law to the projected correlation function w{sub p}(r{sub p}) to marginalize over redshift space distortions and redshift errors. For a real-space correlation function of the form {zeta}(r) = (r/r{sub 0}){sup -{gamma}}, the fitted parameters in comoving coordinates are r{sub 0} = 15.2 {+-} 2.7 h{sup -1} Mpc and {gamma} = 2.0 {+-} 0.3, over a scale range 4 {le} r{sub p} {le} 150 h{sup -1} Mpc. Thus high-redshift quasars are appreciably more strongly clustered than their z {approx} 1.5 counterparts, which have a comoving clustering length r{sub 0} {approx} 6.5 h{sup -1} Mpc. Dividing our sample into two redshift bins: 2.9 {le} z {le} 3.5 and z {ge} 3.5, and assuming a power-law index {gamma} = 2.0, we find a correlation length of r{sub 0} = 16.9 {+-} 1.7 h{sup -1} Mpc for the former, and r{sub 0} = 24.3 {+-} 2.4 h{sup -1} Mpc for the latter. Strong clustering at high redshift indicates that quasars are found in very massive, and therefore highly biased, halos. Following Martini & Weinberg, we relate the clustering strength and quasar number density to the quasar lifetimes and duty cycle. Using the Sheth & Tormen halo mass function, the quasar lifetime is estimated to lie in the range 4 {approx} 50 Myr for quasars with 2.9 {le} z {le} 3.5; and 30 {approx} 600 Myr for quasars with z {ge} 3.5. The corresponding duty cycles are 0.004 {approx} 0.05 for the lower redshift bin and 0.03 {approx} 0.6 for the higher redshift bin. The minimum mass of halos in which these quasars reside is 2-3 x 10{sup 12} h{sup -1} M{sub {circle_dot}} for quasars with 2.9 {le} z {le} 3.5 and 4-6 x 10{sup 12} h{sup -1} M{sub {circle_dot}} for quasars with z {ge} 3.5; the effective bias factor b{sub eff} increases with redshift, e.g., b

  4. First light: exploring the spectra of high-redshift galaxies in the Renaissance Simulations

    Science.gov (United States)

    Barrow, Kirk S. S.; Wise, John H.; Norman, Michael L.; O'Shea, Brian W.; Xu, Hao

    2017-08-01

    We present synthetic observations for the first generations of galaxies in the Universe and make predictions for future deep field observations for redshifts greater than 6. Due to the strong impact of nebular emission lines and the relatively compact scale of H II regions, high-resolution cosmological simulations and a robust suite of analysis tools are required to properly simulate spectra. We created a software pipeline consisting of fsps, hyperion, cloudy and our own tools to generate synthetic IR observations from a fully three-dimensional arrangement of gas, dust, and stars. Our prescription allows us to include emission lines for a complete chemical network and tackle the effect of dust extinction and scattering in the various lines of sight. We provide spectra, 2D binned photon imagery for both HST and JWST IR filters, luminosity relationships, and emission-line strengths for a large sample of high-redshift galaxies in the Renaissance Simulations. Our resulting synthetic spectra show high variability between galactic haloes with a strong dependence on stellar mass, metallicity, gas mass fraction, and formation history. Haloes with the lowest stellar mass have the greatest variability in [O III]/Hβ, [O III], and C III], while haloes with higher masses are seen to show consistency in their spectra and [O III] equivalent widths between 1 and 10 Å. Viewing angle accounted for threefold difference in flux due to the presence of ionized gas channels in a halo. Furthermore, JWST colour plots show a discernible relationship between redshift, colour, and mean stellar age.

  5. A search for faint high-redshift radio galaxy candidates at 150 MHz

    Science.gov (United States)

    Saxena, A.; Jagannathan, P.; Röttgering, H. J. A.; Best, P. N.; Intema, H. T.; Zhang, M.; Duncan, K. J.; Carilli, C. L.; Miley, G. K.

    2018-01-01

    Ultra-steep spectrum (USS) radio sources are good tracers of powerful radio galaxies at z > 2. Identification of even a single bright radio galaxy at z > 6 can be used to detect redshifted 21cm absorption due to neutral hydrogen in the intervening IGM. Here we describe a new sample of high-redshift radio galaxy (HzRG) candidates constructed from the TGSS ADR1 survey at 150 MHz. We employ USS selection (α ≤ -1.3) in ˜10000 square degrees, in combination with strict size selection and non-detections in all-sky optical and infrared surveys. We apply flux density cuts that probe a unique parameter space in flux density (50 < S150 < 200 mJy) to build a sample of 32 HzRG candidates. Follow-up Karl G. Jansky Very Large Array (VLA) observations at 1.4 GHz with an average beam size of 1.3 arcseconds (″) revealed ˜48% of sources to have a single radio component. P-band (370 MHz) imaging of 17 of these sources revealed a flattening radio SED for ten sources at low frequencies, which is expected from compact HzRGs. Two of our sources lie in fields where deeper multi-wavelength photometry and ancillary radio data are available and for one of these we find a best-fit photo-z of 4.8 ± 2.0. The other source has zphot = 1.4 ± 0.1 and a small angular size (3.7″), which could be associated with an obscured star forming galaxy or with a `dead' elliptical. One USS radio source not part of the HzRG sample but observed with the VLA nonetheless is revealed to be a candidate giant radio galaxy with a host galaxy photo-z of 1.8 ± 0.5, indicating a size of 875 kpc.

  6. Massive Clumps in Local Galaxies: Comparisons with High-redshift Clumps

    Science.gov (United States)

    Elmegreen, Bruce G.; Elmegreen, Debra Meloy; Sánchez Almeida, J.; Muñoz-Tuñón, C.; Dewberry, J.; Putko, J.; Teich, Y.; Popinchalk, M.

    2013-09-01

    Local UV-bright galaxies in the Kiso survey include clumpy systems with kiloparsec-size star complexes that resemble clumpy young galaxies in surveys at high redshift. We compare clump masses and underlying disks in several dozen galaxies from each of these surveys to the star complexes and disks of normal spirals. Photometry and spectroscopy for the Kiso and spiral sample come from the Sloan Digital Sky Survey. We find that the largest Kiso clumpy galaxies resemble Ultra Deep Field (UDF) clumpies in terms of the star formation rates, clump masses, and clump surface densities. Clump masses and surface densities in normal spirals are smaller. If the clump masses are proportional to the turbulent Jeans mass in the interstellar medium, then for the most luminous galaxies in the sequence of normal:Kiso:UDF, the turbulent speeds and surface densities increase in the proportions 1.0:4.7:5.0 and 1.0:4.0:5.1, respectively, for fixed restframe B-band absolute magnitude. For the least luminous galaxies in the overlapping magnitude range, the turbulent speed and surface density trends are 1.0:2.7:7.4 and 1.0:1.4:3.0, respectively. We also find that while all three types have radially decreasing disk intensities when measured with ellipse-fit azimuthal averages, the average profiles are more irregular for UDF clumpies (which are viewed in their restframe UV) than for Kiso galaxies (viewed at g-band), and major axis intensity scans are even more irregular for the UDF than Kiso galaxies. Local clumpy galaxies in the Kiso survey appear to be intermediate between UDF clumpies and normal spirals.

  7. MASSIVE CLUMPS IN LOCAL GALAXIES: COMPARISONS WITH HIGH-REDSHIFT CLUMPS

    Energy Technology Data Exchange (ETDEWEB)

    Elmegreen, Bruce G. [IBM Research Division, T. J. Watson Research Center, Yorktown Hts., NY 10598 (United States); Elmegreen, Debra Meloy; Dewberry, J.; Putko, J.; Teich, Y.; Popinchalk, M. [Vassar College, Dept. of Physics and Astronomy, Poughkeepsie, NY 12604 (United States); Sanchez Almeida, J.; Munoz-Tunon, C. [Instituto de Astrof' sica de Canarias, C/via Lactea, s/n, E-38205, La Laguna, Tenerife (Spain)

    2013-09-01

    Local UV-bright galaxies in the Kiso survey include clumpy systems with kiloparsec-size star complexes that resemble clumpy young galaxies in surveys at high redshift. We compare clump masses and underlying disks in several dozen galaxies from each of these surveys to the star complexes and disks of normal spirals. Photometry and spectroscopy for the Kiso and spiral sample come from the Sloan Digital Sky Survey. We find that the largest Kiso clumpy galaxies resemble Ultra Deep Field (UDF) clumpies in terms of the star formation rates, clump masses, and clump surface densities. Clump masses and surface densities in normal spirals are smaller. If the clump masses are proportional to the turbulent Jeans mass in the interstellar medium, then for the most luminous galaxies in the sequence of normal:Kiso:UDF, the turbulent speeds and surface densities increase in the proportions 1.0:4.7:5.0 and 1.0:4.0:5.1, respectively, for fixed restframe B-band absolute magnitude. For the least luminous galaxies in the overlapping magnitude range, the turbulent speed and surface density trends are 1.0:2.7:7.4 and 1.0:1.4:3.0, respectively. We also find that while all three types have radially decreasing disk intensities when measured with ellipse-fit azimuthal averages, the average profiles are more irregular for UDF clumpies (which are viewed in their restframe UV) than for Kiso galaxies (viewed at g-band), and major axis intensity scans are even more irregular for the UDF than Kiso galaxies. Local clumpy galaxies in the Kiso survey appear to be intermediate between UDF clumpies and normal spirals.

  8. Probing Primordial Magnetic Fields with 21-cm Line Observations of the High-redshift Intergalactic Medium

    Science.gov (United States)

    Oklopcic, Antonija; Gluscevic, V.; Hirata, C. M.; Mishra, A.; Venumadhav, T. N.

    2014-01-01

    Coherent magnetic fields with strengths of the order of 10^(-5) G are observed on scales of individual galaxies, including the Milky Way. They are thought to be organized and maintained by a dynamo mechanism. However, the nature and origin of the seed magnetic field, required for the dynamo effect to take place, are still unknown. Here, we propose a method of probing the magnetic field in the intergalactic medium before the Epoch of Reionization through observations of redshifted 21-cm radiation of neutral hydrogen. The 21-cm line is created during the spin-flip transition between the hyperfine levels of the hydrogen ground state. The upper hyperfine level is a triplet consisting of atomic states with three different projections of the total angular momentum vector. Anisotropic 21-cm radiation, resulting from perturbations in the high-redshift IGM, unevenly populates triplet sublevels. If an atom is located in an external magnetic field, it precesses between the three states; this causes an additional anisotropy in the 21-cm radiation, which could be imprinted in the 21-cm power spectrum. In order to evaluate the effect of the magnetic field, we need to consider in full detail all mechanisms that affect the distribution of atoms in hyperfine sublevels, such as the interaction of hydrogen atoms with the 21-cm radiation, optical pumping by Lyman-alpha photons, and spin-exchange in hydrogen-hydrogen collisions. Preliminary calculations suggest that this method could be sensitive to extremely weak magnetic fields, of the order of 10^(-17) G.

  9. Lyα excess in high-redshift radio galaxies: a signature of star formation

    Science.gov (United States)

    Villar-Martín, M.; Humphrey, A.; De Breuck, C.; Fosbury, R.; Binette, L.; Vernet, J.

    2007-03-01

    About 54 per cent of radio galaxies at z >= 3 and 8 per cent of radio galaxies at 2 ~ 2) radio galaxies. These Lyα-excess objects (LAEs) show Lyα/HeII values consistent with or above standard photoionization model predictions. We reject with confidence several scenarios to explain the unusual strength of Lyα in these objects: shocks, low nebular metallicities, high gas densities and absorption/scattering effects. We show that the most successful explanation is the presence of a young stellar population which provides the extra supply of ionizing photons required to explain the Lyα excess in at least the most extreme LAEs (probably in all of them). This interpretation is strongly supported by the tentative trend found by other authors for z >= 3 radio galaxies to show lower ultraviolet rest-frame polarization levels, or the dramatic increase in the detection rate at submm wavelengths of z > 2.5 radio galaxies. The enhanced star formation activity in LAEs could be a consequence of a recent merger which has triggered both the star formation and the active galactic nucleus/radio activities. The measurement of unusually high Lyα ratios in the extended gas of some high-redshift radio galaxies suggests that star formation activity occurs in spatial scales of tens of kpc. We argue that, although the fraction of LAEs may be incompletely determined, both at 2 = 3, the much larger fraction of LAEs found at z >= 3 is a genuine redshift evolution and not due to selection effects. Therefore, our results suggest that the radio galaxy phenomenon is more often associated with a massive starburst at z > 3 than at z < 3. Unpublished results are presented in this paper for the radio galaxy 1338-1941, based on observations carried out at the European Southern Observatory, Paranal (Chile) for the ESO project 69.B-0078(B). E-mail: montse@iaa.es

  10. From nearby low-mass protostars to high redshift starbursts: protostellar outflows tracing the IMF

    Science.gov (United States)

    Kristensen, Lars E.; Bergin, Edwin

    2015-08-01

    Embedded low-mass protostars are notoriously difficult to observe even in the nearest Galactic high-mass clusters where they outnumber the high-mass protostars by orders of magnitude. Thus, without a good tracer of the low-mass population, we do not have a good handle on the shape of the initial (core) mass function, leaving little hope for extrapolating to extragalactic regions where we will never have neither the sensitivity nor the resolution to directly observe this population. A good tracer of the low-mass population is needed.One such physical tracer is outflows. Outflow emission is directly proportional to envelope mass, and outflows are predominantly active during the deeply embedded phases of star formation. What is required for this method to work is species and transitions tracing outflows uniquely such that any signal is not diluted by the surrounding cloud, such as certain methanol transitions, water, high-J CO (J > 10).I will present a statistical model of a forming high-mass cluster. The model includes what we currently know about Galactic high-mass clusters and incorporates outflow emission from low-mass protostars. The latter component is obtained from observations of tens of nearby embedded low-mass protostellar outflows in the above-mentioned tracers. The model is benchmarked against ALMA and Herschel-HIFI observations of Galactic clusters proving the concept, and preliminary extrapolations to the extragalactic regime are presented. With this new probe, and traditional probes of the distant star formation which predominantly trace high mass stars, we will be able to explore the IMF in starburst galaxies from low to high redshift.

  11. Gas clump formation via thermal instability in high-redshift dwarf galaxy mergers

    Science.gov (United States)

    Arata, Shohei; Yajima, Hidenobu; Nagamine, Kentaro

    2018-01-01

    Star formation in high-redshift dwarf galaxies is a key to understand early galaxy evolution in the early Universe. Using the three-dimensional hydrodynamics code GIZMO, we study the formation mechanism of cold, high-density gas clouds in interacting dwarf galaxies with halo masses of ˜3 × 107 M⊙, which are likely to be the formation sites of early star clusters. Our simulations can resolve both the structure of interstellar medium on small scales of ≲ 0.1 pc and the galactic disk simultaneously. We find that the cold gas clouds form in the post-shock region via thermal instability due to metal-line cooling, when the cooling time is shorter than the galactic dynamical time. The mass function of cold clouds shows almost a power-law initially with an upper limit of thermally unstable scale. We find that some clouds merge into more massive ones with ≳ 104 M⊙ within ˜ 2 Myr. Only the massive cold clouds with ≳ 103 M⊙ can keep collapsing due to gravitational instability, resulting in the formation of star clusters. We find that the clump formation is more efficient in the prograde-prograde merger than the prograde-retrograde case due to the difference in the degree of shear flow. In addition, we investigate the dependence of cloud mass function on metallicity and {H2} abundance, and show that the cases with low metallicities (≲ 10-2 Z⊙) or high {H2} abundance (≳ 10-3) cannot form massive cold clouds with ≳ 103 M⊙.

  12. Low Masses and High Redshifts: The Evolution of the Mass-Metallicity Relation

    Science.gov (United States)

    Henry, Alaina; Scarlata, Claudia; Dominguez, Alberto; Malkan, Matthew; Martin, Crystal L.; Siana, Brian; Atek, Hakim; Bedregal, Alejandro G.; Colbert, James W.; Rafelski, Marc; hide

    2013-01-01

    We present the first robust measurement of the high redshift mass-metallicity (MZ) relation at 10(exp 8) grism spectroscopy with the Hubble Space Telescope Wide Field Camera 3 is sensitive to the R23 metallicity diagnostic: ([O II] (lambda)(lambda)3726, 3729 + [OIII] (lambda)(lambda)4959, 5007)/H(beta). Using spectra stacked in four mass quartiles, we find a MZ relation that declines significantly with decreasing mass, extending from 12+log(O/H) = 8.8 at M = 10(exp 9.8) Stellar Mass to 12+log(O/H)= 8.2 at M = 10(exp 8.2) Stellar Mass. After correcting for systematic offsets between metallicity indicators, we compare our MZ relation to measurements from the stacked spectra of galaxies with M > or approx. 10(exp 9.5) Stellar Mass and z approx. 2.3. Within the statistical uncertainties, our MZ relation agrees with the z approx. 2.3 result, particularly since our somewhat higher metallicities (by around 0.1 dex) are qualitatively consistent with the lower mean redshift (z = 1.76) of our sample. For the masses probed by our data, the MZ relation shows a steep slope which is suggestive of feedback from energy-driven winds, and a cosmological downsizing evolution where high mass galaxies reach the local MZ relation at earlier times. In addition, we show that our sample falls on an extrapolation of the star-forming main sequence (the SFR-M* relation) at this redshift. This result indicates that grism emission-line selected samples do not have preferentially high star formation rates (SFRs). Finally, we report no evidence for evolution of the mass-metallicity-SFR plane; our stack-averaged measurements show excellent agreement with the local relation.

  13. Jetted tidal disruptions of stars as a flag of intermediate mass black holes at high redshifts

    Science.gov (United States)

    Fialkov, Anastasia; Loeb, Abraham

    2017-11-01

    Tidal disruption events (TDEs) of stars by single or binary supermassive black holes (SMBHs) brighten galactic nuclei and reveal a population of otherwise dormant black holes. Adopting event rates from the literature, we aim to establish general trends in the redshift evolution of the TDE number counts and their observable signals. We pay particular attention to (I) jetted TDEs whose luminosity is boosted by relativistic beaming and (II) TDEs around binary black holes. We show that the brightest (jetted) TDEs are expected to be produced by massive black hole binaries if the occupancy of intermediate mass black holes (IMBHs) in low-mass galaxies is high. The same binary population will also provide gravitational wave sources for the evolved Laser Interferometer Space Antenna. In addition, we find that the shape of the X-ray luminosity function of TDEs strongly depends on the occupancy of IMBHs and could be used to constrain scenarios of SMBH formation. Finally, we make predictions for the expected number of TDEs observed by future X-ray telescopes finding that a 50 times more sensitive instrument than the Burst Alert Telescope (BAT) on board the Swift satellite is expected to trigger ˜10 times more events than BAT, while 6-20 TDEs are expected in each deep field observed by a telescope 50 times more sensitive than the Chandra X-ray Observatory if the occupation fraction of IMBHs is high. Because of their long decay times, high-redshift TDEs can be mistaken for fixed point sources in deep field surveys and targeted observations of the same deep field with year-long intervals could reveal TDEs.

  14. Exploring the Chemical Link Between Local Ellipticals and Their High-Redshift Progenitors

    Science.gov (United States)

    Leja, Joel; Van Dokkum, Pieter G.; Momcheva, Ivelina; Brammer, Gabriel; Skelton, Rosalind E.; Whitaker, Katherine E.; Andrews, Brett H.; Franx, Marijn; Kriek, Mariska; Van Der Wel, Arjen; hide

    2013-01-01

    We present Keck/MOSFIRE K-band spectroscopy of the first mass-selected sample of galaxies at z approximately 2.3. Targets are selected from the 3D-Hubble Space Telescope Treasury survey. The six detected galaxies have a mean [N II]lambda6584/H-alpha ratio of 0.27 +/- 0.01, with a small standard deviation of 0.05. This mean value is similar to that of UV-selected galaxies of the same mass. The mean gas-phase oxygen abundance inferred from the [N II]/Halpha ratios depends on the calibration method, and ranges from 12+log(O/H)(sub gas) = 8.57 for the Pettini & Pagel calibration to 12+log(O/H)(sub gas) = 8.87 for the Maiolino et al. calibration. Measurements of the stellar oxygen abundance in nearby quiescent galaxies with the same number density indicate 12+log(O/H)(sub stars) = 8.95, similar to the gas-phase abundances of the z approximately 2.3 galaxies if the Maiolino et al. calibration is used. This suggests that these high-redshift star forming galaxies may be progenitors of today's massive early-type galaxies. The main uncertainties are the absolute calibration of the gas-phase oxygen abundance and the incompleteness of the z approximately 2.3 sample: the galaxies with detected Ha tend to be larger and have higher star formation rates than the galaxies without detected H-alpha, and we may still be missing the most dust-obscured progenitors.

  15. Kin encounter rate and inbreeding avoidance in canids

    Science.gov (United States)

    Geffen, Eli; Kam, Michael; Hefner, Reuven; Hersteinsson, Pall; Angerbjorn, Anders; Dalen, Love; Fuglei, Eva; Noren, Karin; Adams, Jennifer R.; Vicetich, John; Meier, Thomas J.; Mech, L.D.; VonHoldt, Bridgett M.; Stahler, Daniel R.; Wayne, Robert K.

    2011-01-01

    Mating with close kin can lead to inbreeding depression through the expression of recessive deleterious alleles and loss of heterozygosity. Mate selection may be affected by kin encounter rate, and inbreeding avoidance may not be uniform but associated with age and social system. Specifically, selection for kin recognition and inbreeding avoidance may be more developed in species that live in family groups or breed cooperatively. To test this hypothesis, we compared kin encounter rate and the proportion of related breeding pairs in noninbred and highly inbred canid populations. The chance of randomly encountering a full sib ranged between 1–8% and 20–22% in noninbred and inbred canid populations, respectively. We show that regardless of encounter rate, outside natal groups mates were selected independent of relatedness. Within natal groups, there was a significant avoidance of mating with a relative. Lack of discrimination against mating with close relatives outside packs suggests that the rate of inbreeding in canids is related to the proximity of close relatives, which could explain the high degree of inbreeding depression observed in some populations. The idea that kin encounter rate and social organization can explain the lack of inbreeding avoidance in some species is intriguing and may have implications for the management of populations at risk.

  16. The Impact of Foregrounds on Redshift Space Distortion Measurements With the Highly-Redshifted 21 cm Line

    OpenAIRE

    Pober, Jonathan C.

    2014-01-01

    The highly redshifted 21 cm line of neutral hydrogen has become recognized as a unique probe of cosmology from relatively low redshifts (z ~ 1) up through the Epoch of Reionization (z ~ 8) and even beyond. To date, most work has focused on recovering the spherically averaged power spectrum of the 21 cm signal, since this approach maximizes the signal-to-noise in the initial measurement. However, like galaxy surveys, the 21 cm signal is affected by redshift space distortions, and is inherently...

  17. The Cycle of Dust in the Milky Ways: Clues from the High-Redshift and the Local Universe

    Science.gov (United States)

    Dwek, Eli

    2008-01-01

    Massive amount of dust has been observed at high-redshifts when the universe was a mere 900 Myr old. The formation and evolution of dust is there dominated by massive stars and interstellar processes. In contrast, in the local universe lower mass stars, predominantly 2-5 Msun AGB stars, play the dominant role in the production of interstellar dust. These two extreme environments offer fascinating clues about the evolution of dust in the Milky Way galaxy

  18. High Redshift Intergalactic C IV Abundance Measurements from the Near-Infrared Spectra of Two z~6 QSOs

    OpenAIRE

    Simcoe, Robert A.

    2006-01-01

    New measurements of the z~6 intergalactic CIV abundance are presented, using moderate resolution IR spectra of two QSOs taken with GNIRS on Gemini South. These data were systematically searched for high redshift CIV absorption lines, using objective selection criteria. Comprehensive tests were performed to quantify sample incompleteness, as well as the rate of false positive CIV identifications. The trend of constant $\\Omega_{CIV}(z)$ observed at z~2-5 appears to continue to z~6, the highest ...

  19. Probing Pre-Galactic Metal Enrichment with High-Redshift Gamma-Ray Bursts

    Science.gov (United States)

    Wang, F. Y.; Bromm, Volker; Greif, Thomas H.; Stacy, Athena; Dai, Z. G.; Loeb, Abraham; Cheng, K. S.

    2012-01-01

    We explore high-redshift gamma-ray bursts (GRBs) as promising tools to probe pre-galactic metal enrichment. We utilize the bright afterglow of a Population III (Pop III) GRB exploding in a primordial dwarf galaxy as a luminous background source, and calculate the strength of metal absorption lines that are imprinted by the first heavy elements in the intergalactic medium (IGM). To derive the GRB absorption line diagnostics, we use an existing highly resolved simulation of the formation of a first galaxy which is characterized by the onset of atomic hydrogen cooling in a halo with virial temperature approximately greater than10(exp 4) K.We explore the unusual circumburst environment inside the systems that hosted Pop III stars, modeling the density evolution with the self-similar solution for a champagne flow. For minihalos close to the cooling threshold, the circumburst density is roughly proportional to (1 + z) with values of about a few cm(exp -3). In more massive halos, corresponding to the first galaxies, the density may be larger, n approximately greater than100 cm(exp -3). The resulting afterglow fluxes are weakly dependent on redshift at a fixed observed time, and may be detectable with the James Webb Space Telescope and Very Large Array in the near-IR and radio wavebands, respectively, out to redshift z approximately greater than 20. We predict that the maximum of the afterglow emission shifts from near-IR to millimeter bands with peak fluxes from mJy to Jy at different observed times. The metal absorption line signature is expected to be detectable in the near future. GRBs are ideal tools for probing the metal enrichment in the early IGM, due to their high luminosities and featureless power-law spectra. The metals in the first galaxies produced by the first supernova (SN) explosions are likely to reside in low-ionization stages (C II, O I, Si II and Fe II). We show that, if the afterglow can be observed sufficiently early, analysis of the metal lines may

  20. GALAXY EVOLUTION AT HIGH REDSHIFT: OBSCURED STAR FORMATION, GRB RATES, COSMIC REIONIZATION, AND MISSING SATELLITES

    Energy Technology Data Exchange (ETDEWEB)

    Lapi, A.; Mancuso, C.; Celotti, A.; Danese, L. [SISSA, Via Bonomea 265, I-34136 Trieste (Italy)

    2017-01-20

    We provide a holistic view of galaxy evolution at high redshifts z ≳ 4, which incorporates the constraints from various astrophysical/cosmological probes, including the estimate of the cosmic star formation rate (SFR) density from UV/IR surveys and long gamma-ray burst (GRBs) rates, the cosmic reionization history following the latest Planck measurements, and the missing satellites issue. We achieve this goal in a model-independent way by exploiting the SFR functions derived by Mancuso et al. on the basis of an educated extrapolation of the latest UV/far-IR data from HST / Herschel , and already tested against a number of independent observables. Our SFR functions integrated down to a UV magnitude limit M {sub UV} ≲ −13 (or SFR limit around 10{sup −2} M {sub ⊙} yr{sup −1}) produce a cosmic SFR density in excellent agreement with recent determinations from IR surveys and, taking into account a metallicity ceiling Z ≲ Z {sub ⊙}/2, with the estimates from long GRB rates. They also yield a cosmic reionization history consistent with that implied by the recent measurements of the Planck mission of the electron scattering optical depth τ {sub es} ≈ 0.058; remarkably, this result is obtained under a conceivable assumption regarding the average value f {sub esc} ≈ 0.1 of the escape fraction for ionizing photons. We demonstrate via the abundance-matching technique that the above constraints concurrently imply galaxy formation becoming inefficient within dark matter halos of mass below a few 10{sup 8} M {sub ⊙}; pleasingly, such a limit is also required so as not to run into the missing satellites issue. Finally, we predict a downturn of the Galaxy luminosity function faintward of M {sub UV} ≲ −12, and stress that its detailed shape, to be plausibly probed in the near future by the JWST , will be extremely informative on the astrophysics of galaxy formation in small halos, or even on the microscopic nature of the dark matter.

  1. LOW MASSES AND HIGH REDSHIFTS: THE EVOLUTION OF THE MASS-METALLICITY RELATION

    Energy Technology Data Exchange (ETDEWEB)

    Henry, Alaina; Straughn, Amber [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Scarlata, Claudia; Bedregal, Alejandro G. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Domínguez, Alberto; Siana, Brian; Masters, Daniel [Department of Physics and Astronomy, University of California, Riverside, Riverside, CA 92521 (United States); Malkan, Matthew; Ross, Nathaniel [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095 (United States); Martin, Crystal L. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Atek, Hakim [Laboratoire d' astrophysique, École Polytechniuqe Fédérale de Lausanne, Observatoire de Sauverny, 1290 Versoix (Switzerland); Colbert, James W.; Rafelski, Marc [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Teplitz, Harry [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States); Bunker, Andrew J. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, OX1 3RH (United Kingdom); Dressler, Alan; Hathi, Nimish; McCarthy, Patrick, E-mail: alaina.henry@nasa.gov [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States)

    2013-10-20

    We present the first robust measurement of the high redshift mass-metallicity (MZ) relation at 10{sup 8} ∼< M/M {sub ☉} ∼< 10{sup 10}, obtained by stacking spectra of 83 emission-line galaxies with secure redshifts between 1.3 ∼< z ∼< 2.3. For these redshifts, infrared grism spectroscopy with the Hubble Space Telescope Wide Field Camera 3 is sensitive to the R {sub 23} metallicity diagnostic: ([O II] λλ3726, 3729 + [O III] λλ4959, 5007)/Hβ. Using spectra stacked in four mass quartiles, we find a MZ relation that declines significantly with decreasing mass, extending from 12+log(O/H) = 8.8 at M = 10{sup 9.8} M {sub ☉}, to 12+log(O/H) = 8.2 at M = 10{sup 8.2} M {sub ☉}. After correcting for systematic offsets between metallicity indicators, we compare our MZ relation to measurements from the stacked spectra of galaxies with M ∼> 10{sup 9.5} M {sub ☉} and z ∼ 2.3. Within the statistical uncertainties, our MZ relation agrees with the z ∼ 2.3 result, particularly since our somewhat higher metallicities (by around 0.1 dex) are qualitatively consistent with the lower mean redshift (z = 1.76) of our sample. For the masses probed by our data, the MZ relation shows a steep slope which is suggestive of feedback from energy-driven winds, and a cosmological downsizing evolution where high mass galaxies reach the local MZ relation at earlier times. In addition, we show that our sample falls on an extrapolation of the star-forming main sequence (the SFR-M {sub *} relation) at this redshift. This result indicates that grism emission-line selected samples do not have preferentially high star formation rates (SFRs). Finally, we report no evidence for evolution of the mass-metallicity-SFR plane; our stack-averaged measurements show excellent agreement with the local relation.

  2. Ultraviolet spectropolarimetry of high-redshift quasars with the Hubble Space Telescope

    Science.gov (United States)

    Impey, C. D.; Malkan, Matthew A.; Webb, Wayne; Petry, C. E.

    1995-01-01

    Ultraviolet spectropolarimetry of three bright high-redshift low-polarization quasars (LPQs) was obtained with the Faint Object Spectrograph of the Hubble Space Telescope (HST). Two of the quasars, PG 1634+706 and PG 2302+029, had polarizations p approximately = 0.5%-1.0% throughout the ultraviolet, and showed no significant variation of polarization amplitude or position angle with wavelength. PG 2302+029 was also marginally (2.4 sigma) circularly polarized in the optical continuum. For the highest redshift quasar, PG 1222+228 (Ton 1530), the polarization was measured down to rest wavelengths below 800 A. Although the continuum of PG 1222+228 was weakened by Lyman limit absorption from an intergalactic gas cloud, the polarization increased sharply from 1% to about 4.5%, a change of 4 sigma significance. This abrupt rise in polarization does not appear attributable to any known instrumental artifact. These UV polarizations were only slightly less than those previously observed for these same objects in the optical. The polarization spectra were flat with a typical slope of the polarized flux pF(sub nu) proportional to nu(exp -0.8 +/- 0.5). Unlike the case of several high luminosity Seyfert 1 nuclei studied previously, polarization caused by scattering from dust grains does not provide the best fit to the polarization spectra of these luminous quasars. These observed spectra are consistent with a wavelength-independent polarization proportional to the total nonstellar light or, possibly, to the contribution of the blue thermal component. The polarization spectra have insufficient signal-to-noise to locate the scatterers with respect to the continuum source and the much larger broad line region. A decrease in amplitude and rotation of the position angle of the polarization vector at the shortest wavelengths, which could result from general relativistic effects near a spinning black hole, was not observed. In fact, in PG 1222+228, the polarization was observed to

  3. High-redshift Post-starburst Galaxies from the Sloan Digital Sky Survey

    Science.gov (United States)

    Pattarakijwanich, Petchara

    in the same object. Given that AGN feedback is thought to be a likely mechanism responsible for quenching star-formation, post-starburst quasars provide ideal laboratory for studying this link. We explored various ways to identify post-starburst quasars, and construct our sample with more than 600 objects at high-redshift. This is the largest sample of post-starburst quasars available in the literature, and will be useful for AGN feedback studies. Finally, we studied the clustering properties of post-starburst galaxies through cross-correlation with CMASS galaxies. The real-space cross correlation function is a power-law with correlation length r0 ˜ 9.2 Mpc, and power-law index gamma ˜ 1.8. We also measure the linear bias of post-starburst galaxies to be bPSG ˜ 1.74 at redshift z = 0.62, corresponding to a dark matter halo mass of Mhalo ˜ 1.5 x 1013 M [special characters removed]. We found no evidence for redshift evolution in clustering properties for post-starburst galaxies.

  4. The long lives of giant clumps and the birth of outflows in gas-rich galaxies at high redshift

    Energy Technology Data Exchange (ETDEWEB)

    Bournaud, Frédéric; Renaud, Florent; Daddi, Emanuele; Duc, Pierre-Alain; Elbaz, David; Gabor, Jared M.; Juneau, Stéphanie; Kraljic, Katarina; Le Floch' , Emeric [CEA, IRFU/SAp, F-91191 Gif-Sur-Yvette (France); Perret, Valentin; Amram, Philippe; Epinat, Benoit [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille), F-13388 Marseille (France); Dekel, Avishai [Center for Astrophysics and Planetary Science, Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Elmegreen, Bruce G. [IBM Research Division, T.J. Watson Research Center, Yorktown Heights, NY 10598 (United States); Elmegreen, Debra M. [Department of Physics and Astronomy, Vassar College, Poughkeepsie, NY 12604 (United States); Teyssier, Romain [Institute for Theoretical Physics, University of Zurich, CH-8057 Zurich (Switzerland)

    2014-01-01

    Star-forming disk galaxies at high redshift are often subject to violent disk instability, characterized by giant clumps whose fate is yet to be understood. The main question is whether the clumps disrupt within their dynamical timescale (≤50 Myr), like the molecular clouds in today's galaxies, or whether they survive stellar feedback for more than a disk orbital time (≈300 Myr) in which case they can migrate inward and help building the central bulge. We present 3.5-7 pc resolution adaptive mesh refinement simulations of high-redshift disks including photoionization, radiation pressure, and supernovae feedback. Our modeling of radiation pressure determines the mass loading and initial velocity of winds from basic physical principles. We find that the giant clumps produce steady outflow rates comparable to and sometimes somewhat larger than their star formation rate, with velocities largely sufficient to escape the galaxy. The clumps also lose mass, especially old stars, by tidal stripping, and the stellar populations contained in the clumps hence remain relatively young (≤200 Myr), as observed. The clumps survive gaseous outflows and stellar loss, because they are wandering in gas-rich turbulent disks from which they can reaccrete gas at high rates compensating for outflows and tidal stripping, overall keeping realistic and self-regulated gaseous and stellar masses. The outflow and accretion rates have specific timescales of a few 10{sup 8} yr, as opposed to rapid and repeated dispersion and reformation of clumps. Our simulations produce gaseous outflows with velocities, densities, and mass loading consistent with observations, and at the same time suggest that the giant clumps survive for hundreds of Myr and complete their migration to the center of high-redshift galaxies. These long-lived clumps are gas-dominated and contain a moderate mass fraction of stars; they drive inside-out disk evolution, thickening, spheroid growth, and fueling of the central

  5. A unified model for the maximum mass scales of molecular clouds, stellar clusters and high-redshift clumps

    Science.gov (United States)

    Reina-Campos, Marta; Kruijssen, J. M. Diederik

    2017-08-01

    We present a simple, self-consistent model to predict the maximum masses of giant molecular clouds (GMCs), stellar clusters and high-redshift clumps as a function of the galactic environment. Recent works have proposed that these maximum masses are set by shearing motions and centrifugal forces, but we show that this idea is inconsistent with the low masses observed across an important range of local-Universe environments, such as low-surface density galaxies and galaxy outskirts. Instead, we propose that feedback from young stars can disrupt clouds before the global collapse of the shear-limited area is completed. We develop a shear-feedback hybrid model that depends on three observable quantities: the gas surface density, the epicylic frequency and the Toomre parameter. The model is tested in four galactic environments: the Milky Way, the Local Group galaxy M31, the spiral galaxy M83 and the high-redshift galaxy zC406690. We demonstrate that our model simultaneously reproduces the observed maximum masses of GMCs, clumps and clusters in each of these environments. We find that clouds and clusters in M31 and in the Milky Way are feedback-limited beyond radii of 8.4 and 4 kpc, respectively, whereas the masses in M83 and zC406690 are shear-limited at all radii. In zC406690, the maximum cluster masses decrease further due to their inspiral by dynamical friction. These results illustrate that the maximum masses change from being shear-limited to being feedback-limited as galaxies become less gas rich and evolve towards low shear. This explains why high-redshift clumps are more massive than GMCs in the local Universe.

  6. Star-forming galactic contrails as a source of metal enrichment and ionizing radiation at high redshift

    Science.gov (United States)

    Rauch, Michael; Becker, George D.; Haehnelt, Martin G.; Gauthier, Jean-Rene

    2014-06-01

    A spectroscopically detected Lyman α emitting halo at redshift 3.216 in the GOODS-N field is found to reside at the convergence of several line-emitting filaments. Spatially extended emission apparently by He II 1640 Å and several metal transitions is seen within several arcseconds from the position of the central galaxy. The V = 24.9 galaxy mainly responsible for the continuum emission at the centre of the halo has broad-band colours and spectral features consistent with a z = 3.216 star-forming galaxy. Hubble Space Telescope images show that some of the filaments coincide, in projection, with several, mostly blue galaxies, with pronounced head-tail structures partly aligned with each other. These objects, for which we cannot rule that they are foreground, chance projections in front of the high-redshift halo, are seen over an area with a linear extent of at least 12 arcsec. The broad-band images of some galaxies suggest the presence of ram-pressure stripping, including possible evidence for recent star formation in the stripped contrails. Spatial gradients in the appearance of several galaxies may represent a stream of galaxies passing from a colder to a hotter intergalactic medium. The release of the enriched interstellar medium from galaxies and the occurrence of star formation and stellar feedback in the galactic contrails suggest a mechanism for the metal enrichment of the high-redshift intergalactic medium that does not require long-range galactic winds. If these galaxies are at the same redshift as the Lyα halo, their very blue colours may be a consequence of the stripping of gas. A stripped stellar population and star formation in galactic contrails suggest promising sites for the escape of ionizing radiation from high-redshift galaxies.

  7. Imaging Cold Gas to 1 kpc scales in high-redshift galaxies with the ngVLA

    Science.gov (United States)

    Casey, Caitlin; Narayanan, Desika; Dave, Romeel; Hung, Chao-Ling; Champagne, Jaclyn; Carilli, Chris Luke; Decarli, Roberto; Murphy, Eric J.; Popping, Gergo; Riechers, Dominik; Somerville, Rachel S.; Walter, Fabian

    2017-01-01

    The next generation Very Large Array (ngVLA) will revolutionize our understanding of the distant Universe via the detection of cold molecular gas in the first galaxies. Its impact on studies of galaxy characterization via detailed gas dynamics will provide crucial insight on dominant physical drivers for star-formation in high redshift galaxies, including the exchange of gas from scales of the circumgalactic medium down to resolved clouds on mass scales of ~10^5 M_sun. In this study, we employ a series of high-resolution, cosmological, hydrodynamic zoom simulations from the MUFASA simulation suite and a CASA simulator to generate mock ngVLA observations. Based on a direct comparison between the inferred results from our mock observations and the cosmological simulations, we investigate the capabilities of ngVLA to constrain the mode of star formation, dynamical mass, and molecular gas kinematics in individual high-redshift galaxies using cold gas tracers like CO(1-0) and CO(2-1). Using the Despotic radiative transfer code that encompasses simultaneous thermal and statistical equilibrium in calculating the molecular and atomic level populations, we generate parallel mock observations of high-J transitions of CO and C+ from ALMA for comparison. The factor of 100 times improvement in mapping speed for the ngVLA beyond the Jansky VLA and the proposed ALMA Band 1 will make these detailed, high-resolution imaging and kinematic studies routine at z=2 and beyond.

  8. A LINK TO THE PAST: USING MARKOV CHAIN MONTE CARLO FITTING TO CONSTRAIN FUNDAMENTAL PARAMETERS OF HIGH-REDSHIFT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Pirzkal, N.; Rothberg, B.; Koekemoer, Anton [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Nilsson, Kim K. [ST-ECF, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Muenchen (Germany); Finkelstein, S. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Malhotra, Sangeeta; Rhoads, James, E-mail: npirzkal@stsci.edu [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States)

    2012-04-01

    We have developed a new method for fitting spectral energy distributions (SEDs) to identify and constrain the physical properties of high-redshift (4 < z < 8) galaxies. Our approach uses an implementation of Bayesian based Markov Chain Monte Carlo that we have dubbed '{pi}MC{sup 2}'. It allows us to compare observations to arbitrarily complex models and to compute 95% credible intervals that provide robust constraints for the model parameters. The work is presented in two sections. In the first, we test {pi}MC{sup 2} using simulated SEDs to not only confirm the recovery of the known inputs but to assess the limitations of the method and identify potential hazards of SED fitting when applied specifically to high-redshift (z > 4) galaxies. In the second part of the paper we apply {pi}MC{sup 2} to thirty-three 4 < z < 8 objects, including the spectroscopically confirmed Grism ACS Program for Extragalactic Science Ly{alpha} sample (4 < z < 6), supplemented by newly obtained Hubble Space Telescope/WFC3 near-IR observations, and several recently reported broadband selected z > 6 galaxies. Using {pi}MC{sup 2}, we are able to constrain the stellar mass of these objects and in some cases their stellar age and find no evidence that any of these sources formed at a redshift larger than z = 8, a time when the universe was Almost-Equal-To 0.6 Gyr old.

  9. A shared system of representation governing quantity discrimination in canids

    Directory of Open Access Journals (Sweden)

    Joseph M Baker

    2012-10-01

    Full Text Available One way to investigate the evolution of cognition is to compare the abilities of phylogenetically related species. The domestic dog (Canis lupus familiaris, for example, still shares cognitive abilities with the coyote (C. latrans. Both of these canids possess the ability to make psychophysical less/more discriminations of food based on quantity. Like many other species including humans, this ability is mediated by Weber’s Law: discrimination of continuous quantities is dependent on the ratio between the two quantities. As two simultaneously presented quantities of food become more similar, choice of the large or small option becomes random in both dogs and coyotes. It remains unknown, however, whether these closely related species within the same family—one domesticated, and one wild—make such quantitative comparisons with comparable accuracy. Has domestication honed or diminished this quantitative ability? Might different selective and ecological pressures facing coyotes drive them to be more or less able to accurately represent and discriminate food quantity than domesticated dogs? This study is an effort to elucidate this question concerning the evolution of non-verbal quantitative cognition.Here, we tested the quantitative discrimination ability of 16 domesticated dogs. Each animal was given 9 trials in which two different quantities of food were simultaneously displayed to them. The domesticated dogs’ performance on this task was then compared directly to the data from 16 coyotes’ performance on this same task reported by Baker and colleagues (2011.The quantitative discrimination abilities between the two species were strikingly similar. Domesticated dogs demonstrated similar quantitative sensitivity as coyotes, suggesting that domestication may not have significantly altered the psychophysical discrimination abilities of canids. Instead, this study provides further evidence for similar nonverbal quantitative abilities across

  10. A Shared System of Representation Governing Quantity Discrimination in Canids

    Science.gov (United States)

    Baker, Joseph M.; Morath, Justice; Rodzon, Katrina S.; Jordan, Kerry E.

    2012-01-01

    One way to investigate the evolution of cognition is to compare the abilities of phylogenetically related species. The domestic dog (Canis lupus familiaris), for example, still shares cognitive abilities with the coyote (Canis latrans). Both of these canids possess the ability to make psychophysical “less/more” discriminations of food based on quantity. Like many other species including humans, this ability is mediated by Weber’s Law: discrimination of continuous quantities is dependent on the ratio between the two quantities. As two simultaneously presented quantities of food become more similar, choice of the large or small option becomes random in both dogs and coyotes. It remains unknown, however, whether these closely related species within the same family – one domesticated, and one wild – make such quantitative comparisons with comparable accuracy. Has domestication honed or diminished this quantitative ability? Might different selective and ecological pressures facing coyotes drive them to be more or less able to accurately represent and discriminate food quantity than domesticated dogs? This study is an effort to elucidate this question concerning the evolution of non-verbal quantitative cognition. Here, we tested the quantitative discrimination ability of 16 domesticated dogs. Each animal was given nine trials in which two different quantities of food were simultaneously displayed to them. The domesticated dogs’ performance on this task was then compared directly to the data from 16 coyotes’ performance on this same task reported by Baker et al. (2011). The quantitative discrimination abilities between the two species were strikingly similar. Domesticated dogs demonstrated similar quantitative sensitivity as coyotes, suggesting that domestication may not have significantly altered the psychophysical discrimination abilities of canids. Instead, this study provides further evidence for similar non-verbal quantitative abilities across multiple

  11. A robust morphological classification of high-redshift galaxies using support vector machines on seeing limited images. I. Method description

    Science.gov (United States)

    Huertas-Company, M.; Rouan, D.; Tasca, L.; Soucail, G.; Le Fèvre, O.

    2008-02-01

    Context: Morphology is the most accessible tracer of the physical structure of galaxies, but its interpretation in the framework of galaxy evolution still remains a problem. Its dependence on wavelength renders the comparison between local and high redshift populations difficult. Furthermore, the quality of the measured morphology being strongly dependent on the image resolution, the comparison between different surveys is also a problem. Aims: We present a new non-parametric method to quantify morphologies of galaxies based on a particular family of learning machines called support vector machines. The method, which can be seen as a generalization of the classical C/A classification but with an unlimited number of dimensions and non-linear boundaries between decision regions, is fully automated and thus particularly well adapted to large cosmological surveys. The source code is available for download at http://www.lesia.obspm.fr/~huertas/galsvm.html Methods: To test the method, we use a seeing limited near-infrared (Ks band, 2,16 μm) sample observed with WIRCam at CFHT at a median redshift of z ~ 0.8. The machine is trained with a simulated sample built from a local visually classified sample from the SDSS, chosen in the high-redshift sample's rest-frame (i band, 0.77 μm) and artificially redshifted to match the observing conditions. We use a 12-dimensional volume, including 5 morphological parameters, and other characteristics of galaxies such as luminosity and redshift. A fraction of the simulated sample is used to test the machine and assess its accuracy. Results: We show that a qualitative separation in two main morphological types (late type and early type) can be obtained with an error lower than 20% up to the completeness limit of the sample (KAB ~ 22), which is more than 2 times better that what would be obtained with a classical C/A classification on the same sample and indeed comparable to space data. The method is optimized to solve a specific problem

  12. The variance of dispersion measure of high-redshift transient objects as a probe of ionized bubble size during reionization

    Science.gov (United States)

    Yoshiura, Shintaro; Takahashi, Keitaro

    2018-01-01

    The dispersion measure (DM) of high-redshift (z ≳ 6) transient objects such as fast radio bursts can be a powerful tool to probe the intergalactic medium during the Epoch of Reionization. In this paper, we study the variance of the DMs of objects with the same redshift as a potential probe of the size distribution of ionized bubbles. We calculate the DM variance with a simple model with randomly distributed spherical bubbles. It is found that the DM variance reflects the characteristics of the probability distribution of the bubble size. We find that the variance can be measured precisely enough to obtain the information on the typical size with a few hundred sources at a single redshift.

  13. The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Molecular Gas Reservoirs in High-redshift Galaxies

    Science.gov (United States)

    Decarli, Roberto; Walter, Fabian; Aravena, Manuel; Carilli, Chris; Bouwens, Rychard; da Cunha, Elisabete; Daddi, Emanuele; Elbaz, David; Riechers, Dominik; Smail, Ian; Swinbank, Mark; Weiss, Axel; Bacon, Roland; Bauer, Franz; Bell, Eric F.; Bertoldi, Frank; Chapman, Scott; Colina, Luis; Cortes, Paulo C.; Cox, Pierre; Gónzalez-López, Jorge; Inami, Hanae; Ivison, Rob; Hodge, Jacqueline; Karim, Alex; Magnelli, Benjamin; Ota, Kazuaki; Popping, Gergö; Rix, Hans-Walter; Sargent, Mark; van der Wel, Arjen; van der Werf, Paul

    2016-12-01

    We study the molecular gas properties of high-z galaxies observed in the ALMA Spectroscopic Survey (ASPECS) that targets an ˜1 arcmin2 region in the Hubble Ultra Deep Field (UDF), a blind survey of CO emission (tracing molecular gas) in the 3 and 1 mm bands. Of a total of 1302 galaxies in the field, 56 have spectroscopic redshifts and correspondingly well-defined physical properties. Among these, 11 have infrared luminosities {L}{IR}\\gt {10}11 {L}⊙ , i.e., a detection in CO emission was expected. Out of these, 7 are detected at various significance in CO, and 4 are undetected in CO emission. In the CO-detected sources, we find CO excitation conditions that are lower than those typically found in starburst/sub-mm galaxy/QSO environments. We use the CO luminosities (including limits for non-detections) to derive molecular gas masses. We discuss our findings in the context of previous molecular gas observations at high redshift (star formation law, gas depletion times, gas fractions): the CO-detected galaxies in the UDF tend to reside on the low-{L}{IR} envelope of the scatter in the {L}{IR}{--}{L}{CO}\\prime relation, but exceptions exist. For the CO-detected sources, we find an average depletion time of ˜1 Gyr, with significant scatter. The average molecular-to-stellar mass ratio ({M}{{H}2}/M *) is consistent with earlier measurements of main-sequence galaxies at these redshifts, and again shows large variations among sources. In some cases, we also measure dust continuum emission. On average, the dust-based estimates of the molecular gas are a factor ˜2-5× smaller than those based on CO. When we account for detections as well as non-detections, we find large diversity in the molecular gas properties of the high-redshift galaxies covered by ASPECS.

  14. THERMAL AND RADIATIVE ACTIVE GALACTIC NUCLEUS FEEDBACK HAVE A LIMITED IMPACT ON STAR FORMATION IN HIGH-REDSHIFT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Roos, Orianne; Juneau, Stéphanie; Bournaud, Frédéric; Gabor, Jared M., E-mail: orianne.roos@cea.fr [CEA-Saclay, F-91190 Gif-sur-Yvette (France)

    2015-02-10

    The effects of active galactic nuclei (AGNs) on their host galaxies depend on the coupling between the injected energy and the interstellar medium (ISM). Here, we model and quantify the impact of long-range AGN ionizing radiation—in addition to the often considered small-scale energy deposition—on the physical state of the multi-phase ISM of the host galaxy and on its total star formation rate (SFR). We formulate an AGN spectral energy distribution matched with observations, which we use with the radiative transfer (RT) code Cloudy to compute AGN ionization in a simulated high-redshift disk galaxy. We use a high-resolution (∼6 pc) simulation including standard thermal AGN feedback and calculate RT in post-processing. Surprisingly, while these models produce significant AGN-driven outflows, we find that AGN ionizing radiation and heating reduce the SFR by a few percent at most for a quasar luminosity (L {sub bol} = 10{sup 46.5} erg s{sup –1}). Although the circumgalactic gaseous halo can be kept almost entirely ionized by the AGN, most star-forming clouds (n ≳ 10{sup 2} {sup –} {sup 3} cm{sup –3}) and even the reservoirs of cool atomic gas (n ∼ 0.3-10 cm{sup –3})—which are the sites of future star formation (SF; 100-200 Myr), are generally too dense to be significantly affected. Our analysis ignores any absorption from a putative torus, making our results upper limits on the effects of ionizing radiation. Therefore, while the AGN-driven outflows can remove substantial amounts of gas in the long term, the impact of AGN feedback on the SF efficiency in the interstellar gas in high-redshift galaxies is marginal, even when long-range radiative effects are accounted for.

  15. Infectious diseases in Yellowstone’s canid community

    Science.gov (United States)

    Almberg, Emily S.; Cross, Paul C.; Mech, L. David; Smith, Doug W.; Sheldon, Jennifer W.; Crabtree, Robert L.

    2011-01-01

    Each summer Yellowstone Wolf Project staff visit den sites to monitor the success of wolf reproduction and pup rearing behavior. For the purposes of wolf monitoring, Yellowstone National Park (YNP) is divided into two study areas, the northern range and the interior, each distinguished by their ecological and physiographical differences. The 1,000 square kilometer northern range, characterized by lower elevations (1,500–2,200 m), serves as prime winter habitat for ungulates and supports a higher density of wolves than the interior (20–99 wolves/1,000 km2 versus 2–11 wolves/1,000 km2). The interior of the park encompasses 7,991 square kilometers, is higher in elevation, receives higher annual snowfall, and generally supports lower densities of wolves and ungulates. During the Yellowstone Wolf Project’s 2005 observations on the northern range, researchers noticed that some wolf pups were disappearing and those that remained were unusually listless. The Slough Creek pups, at first numbering 18, dwindled to three survivors. Similar findings were mirrored at other den sites across the northern range. When annual den surveys were conducted in late July, all that remained were scattered piles of bones and fur. Coyotes suffered similar setbacks in 2005, with many of the survivors exhibiting neurological shakes and tremors. The park’s canids had been affected by something, but what? Prompted by what seemed to be a disease outbreak, the Yellowstone Wolf Project, the Yellowstone Ecological Research Center (YERC), and the University of Minnesota decided to take several collaborative approaches toward improving our understanding of the presence and role of infectious disease in Yellowstone’s canid community. Several serological studies have been conducted in the past among the park’s coyotes (Gese et al. 1997) and cougars (Biek 2006), providing a helpful foundation on which to build and compare. A serological survey was conducted, using serum samples collected

  16. THE RADIO PROPERTIES OF HIGH-REDSHIFT QUASARS .1. DUAL-FREQUENCY OBSERVATIONS OF 79 STEEP-SPECTRUM QUASARS AT Z-GREATER-THAN-1.5

    NARCIS (Netherlands)

    LONSDALE, CJ; BARTHEL, PD; MILEY, GK

    We have made sensitive VLA observations of virtually all known high-redshift (z > 1.5) radio-loud QSOs with extended radio morphologies. The resulting images (at 6 and 2 cm wavelength, including linear polarization) have angular resolutions of typically 0.''4 and 0.''15 and are compiled here. This

  17. Dark-ages reionization and galaxy formation simulation-XI. Clustering and halo masses of high redshift galaxies

    Science.gov (United States)

    Park, Jaehong; Kim, Han-Seek; Liu, Chuanwu; Trenti, Michele; Duffy, Alan R.; Geil, Paul M.; Mutch, Simon J.; Poole, Gregory B.; Mesinger, Andrei; Wyithe, J. Stuart B.

    2017-12-01

    We investigate the clustering properties of Lyman-break galaxies (LBGs) at z ∼ 6 - 8. Using the semi-analytical model MERAXES constructed as part of the dark-ages reionization and galaxy-formation observables from numerical simulation (DRAGONS) project, we predict the angular correlation function (ACF) of LBGs at z ∼ 6 - 8. Overall, we find that the predicted ACFs are in good agreement with recent measurements at z ∼ 6 and z ∼ 7.2 from observations consisting of the Hubble eXtreme Deep Field, the Hubble Ultra Deep Field and cosmic sssembly near-infrared deep extragalactic legacy survey field. We confirm the dependence of clustering on luminosity, with more massive dark matter haloes hosting brighter galaxies, remains valid at high redshift. The predicted galaxy bias at fixed luminosity is found to increase with redshift, in agreement with observations. We find that LBGs of magnitude MAB(1600) < -19.4 at 6 ≲ z ≲ 8 reside in dark matter haloes of mean mass ∼1011.0-1011.5 M⊙, and this dark matter halo mass does not evolve significantly during reionisation.

  18. Fluctuating feedback-regulated escape fraction of ionizing radiation in low-mass, high-redshift galaxies

    Science.gov (United States)

    Trebitsch, Maxime; Blaizot, Jérémy; Rosdahl, Joakim; Devriendt, Julien; Slyz, Adrianne

    2017-09-01

    Low-mass galaxies are thought to provide the bulk of the ionizing radiation necessary to reionize the Universe. The amount of photons escaping the galaxies is poorly constrained theoretically, and difficult to measure observationally. Yet it is an essential parameter of reionization models. We study in detail how ionizing radiation can leak from high-redshift galaxies. For this purpose, we use a series of high-resolution radiation hydrodynamics simulations, zooming on three dwarf galaxies in a cosmological context. We find that the energy and momentum input from the supernova explosions has a pivotal role in regulating the escape fraction by disrupting dense star-forming clumps, and clearing sightlines in the halo. In the absence of supernovae, photons are absorbed very locally, within the birth clouds of massive stars. We follow the time evolution of the escape fraction and find that it can vary by more than six orders of magnitude. This explains the large scatter in the value of the escape fraction found by previous studies. This fast variability also impacts the observability of the sources of reionization: a survey even as deep as M1500 = -14 would miss about half of the underlying population of Lyman-continuum emitters.

  19. Efficient cold outflows driven by cosmic rays in high redshift galaxies and their global effects on the IGM

    Science.gov (United States)

    Samui, Saumyadip; Subramanian, Kandaswamy; Srianand, Raghunathan

    2018-02-01

    We present semi-analytical models of galactic outflows in high redshift galaxies driven by both hot thermal gas and non-thermal cosmic rays. Thermal pressure alone may not sustain a large scale outflow in low mass galaxies (i.e M ˜ 108 M⊙), in the presence of supernovae (SNe) feedback with large mass loading. We show that inclusion of cosmic ray pressure allows outflow solutions even in these galaxies. In massive galaxies for the same energy efficiency, cosmic ray driven winds can propagate to larger distances compared to pure thermally driven winds. On an average gas in the cosmic ray driven winds has a lower temperature which could aid detecting it through absorption lines in the spectra of background sources. Using our constrained semi-analytical models of galaxy formation (that explains the observed UV luminosity functions of galaxies) we study the influence of cosmic ray driven winds on the properties of the intergalactic medium (IGM) at different redshifts. In particular, we study the volume filling factor, average metallicity, cosmic ray and magnetic field energy densities for models invoking atomic cooled and molecular cooled halos. We show that the cosmic rays in the IGM could have enough energy that can be transferred to the thermal gas in presence of magnetic fields to influence the thermal history of the intergalactic medium. The significant volume filling and resulting strength of IGM magnetic fields can also account for recent γ-ray observations of blazars.

  20. Newborn spheroids at high redshift: when and how did the dominant, old stars in today's massive galaxies form?

    Science.gov (United States)

    Kaviraj, S.; Cohen, S.; Ellis, R. S.; Peirani, S.; Windhorst, R. A.; O'Connell, R. W.; Silk, J.; Whitmore, B. C.; Hathi, N. P.; Ryan, R. E.; Dopita, M. A.; Frogel, J. A.; Dekel, A.

    2013-01-01

    We study ˜330 massive (M* > 109.5 M⊙), newborn spheroidal galaxies (SGs) around the epoch of peak star formation (1 explore the high-redshift origin of SGs and gain insight into when and how the old stellar populations that dominate today's Universe formed. The sample is drawn from the Hubble Space Telescope (HST)/WFC3 Early-Release Science programme, which provides deep 10-filter (0.2-1.7 μm) HST imaging over one-third of the GOODS-South field. We find that the star formation episodes that built our SGs likely peaked in the redshift range 2 values ( 1010.5 M⊙, and an age trend becomes evident in this mass regime: SGs with M* > 1011.5 M⊙ are ˜2 Gyr older than their counterparts with M* violent disc instability driven by cold streams and/or minor mergers) likely play a dominant role in building SGs, and creating a significant fraction of the old stellar populations that dominate today's Universe.

  1. Comparing Low-Redshift Compact Dwarf Starbursts in the RESOLVE Survey with High-Redshift Blue Nuggets

    Science.gov (United States)

    Palumbo, Michael Louis; Kannappan, Sheila; Snyder, Elaine; Eckert, Kathleen; Norman, Dara; Fraga, Luciano; Quint, Bruno; Amram, Philippe; Mendes de Oliveira, Claudia; RESOLVE Team

    2018-01-01

    We identify and characterize a population of compact dwarf starburst galaxies in the RESOLVE survey, a volume-limited census of galaxies in the local universe, to probe the possibility that these galaxies are related to “blue nuggets,” a class of intensely star-forming and compact galaxies previously identified at high redshift. Blue nuggets are thought to form as the result of intense compaction events that drive fresh gas to their centers. They are expected to display prolate morphology and rotation along their minor axes. We report IFU observations of three of our compact dwarf starburst galaxies, from which we construct high-resolution velocity fields, examining the evidence for minor axis or otherwise misaligned rotation. We find multiple cases of double nuclei in our sample, which may be indicative of a merger origin as in some blue nugget formation scenarios. We compare the masses, radii, gas-to-stellar mass ratios, star formation rates, stellar surface mass densities, and environmental contexts of our sample to expectations for blue nuggets.

  2. The combined effect of AGN and supernovae feedback in launching massive molecular outflows in high-redshift galaxies

    Science.gov (United States)

    Biernacki, Pawel; Teyssier, Romain

    2018-01-01

    We have recently improved our model of active galactic nucleus (AGN) by attaching the supermassive black hole (SMBH) to a massive nuclear star cluster (NSC). Here we study the effects of this new model in massive, gas-rich galaxies with several simulations of different feedback recipes with the hydrodynamics code RAMSES. These simulations are compared to a reference simulation without any feedback, in which the cooling halo gas is quickly consumed in a burst of star formation. In the presence of strong supernovae (SN) feedback, we observe the formation of a galactic fountain that regulates star formation over a longer period, but without halting it. If only AGN feedback is considered, as soon as the SMBH reaches a critical mass, strong outflows of hot gas are launched and prevent the cooling halo gas from reaching the disk, thus efficiently halting star formation, leading to the so-called "quenching". If both feedback mechanisms act in tandem, we observe a non-linear coupling, in the sense that the dense gas in the supernovae-powered galactic fountain is propelled by the hot outflow powered by the AGN at much larger radii than without AGN. We argue that these particular outflows are able to unbind dense gas from the galactic halo, thanks to the combined effect of SN and AGN feedback. We speculate that this mechanism occurs at the end of the fast growing phase of SMBH, and is at the origin of the dense molecular outflows observed in many massive high-redshift galaxies.

  3. Dark-ages reionization and galaxy-formation simulation - VII. The sizes of high-redshift galaxies

    Science.gov (United States)

    Liu, Chuanwu; Mutch, Simon J.; Poole, Gregory B.; Angel, P. W.; Duffy, Alan R.; Geil, Paul M.; Mesinger, Andrei; Wyithe, J. Stuart B.

    2017-03-01

    We investigate high-redshift galaxy sizes using a semi-analytic model constructed for the Dark-ages Reionization And Galaxy-formation Observables from Numerical Simulation project. Our fiducial model, including strong feedback from supernovae and photoionization background, accurately reproduces the evolution of the stellar mass function and ultraviolet (UV) luminosity function. Using this model, we study the size-luminosity relation of galaxies and find that the effective radius scales with UV luminosity as Re ∝ L0.25 at z ∼ 5-9. We show that recently discovered very luminous galaxies at z ∼ 7 and 11 lie on our predicted size-luminosity relations. We find that a significant fraction of galaxies at z > 8 will not be resolved by James Webb Space Telescope, but Giant Magellan Telescope will have the ability to resolve all galaxies in haloes above the atomic cooling limit. We show that our fiducial model successfully reproduces the redshift evolution of average galaxy sizes at z > 5. We also explore galaxy sizes in models without supernova feedback. The no-supernova feedback models produce galaxy sizes that are smaller than observations. We therefore confirm that supernova feedback plays an important role in determining the size-luminosity relation of galaxies and its redshift evolution during reionization.

  4. Are High-redshift Galaxies Hot? Temperature of z > 5 Galaxies and Implications for Their Dust Properties

    Science.gov (United States)

    Faisst, Andreas L.; Capak, Peter L.; Yan, Lin; Pavesi, Riccardo; Riechers, Dominik A.; Barišić, Ivana; Cooke, Kevin C.; Kartaltepe, Jeyhan S.; Masters, Daniel C.

    2017-09-01

    Recent studies have found a significant evolution and scatter in the relationship between the UV spectral slope (β UV) and the infrared excess (IRX; L IR/L UV) at z > 4, suggesting different dust properties of these galaxies. The total far-infrared (FIR) luminosity is key for this analysis, but it is poorly constrained in normal (main-sequence) star-forming z > 5 galaxies, where often only one single FIR point is available. To better inform estimates of the FIR luminosity, we construct a sample of local galaxies and three low-redshift analogues of z > 5 systems. The trends in this sample suggest that normal high-redshift galaxies have a warmer infrared (IR) spectral energy distribution (SED) compared to average z total FIR luminosities, which removes some tension between the dust attenuation models and observations of the IRX-β relation at z > 5. Despite this, some galaxies still fall below the minimum IRX-β relation derived with standard dust cloud models. We propose that radiation pressure in these highly star-forming galaxies causes a spatial offset between dust clouds and young star-forming regions within the lifetime of O/B stars. These offsets change the radiation balance and create viewing-angle effects that can change UV colors at fixed IRX. We provide a modified model that can explain the location of these galaxies on the IRX-β diagram.

  5. Phylogenetic analysis of rabies virus isolated from canids in North and Northeast Brazil.

    Science.gov (United States)

    de Souza, Débora Nunes; Carnieli, Pedro; Macedo, Carla Isabel; de Novaes Oliveira, Rafael; de Carvalho Ruthner Batista, Helena Beatriz; Rodrigues, Adriana Candido; Pereira, Patricia Mariano Cruz; Achkar, Samira Maria; Vieira, Luiz Fernando Pereira; Kawai, Juliana Galera Castilho

    2017-01-01

    Cases of canine rabies continue to occur in North and Northeast Brazil, and the number of notifications of rabies cases in wild canids has increased as a result of the expansion of urban areas at the expense of areas with native vegetation. In light of this, we performed molecular characterization of rabies virus isolates from dogs and Cerdocyon thous from various states in North and Northeast Brazil. In all, 102 samples from dogs (n = 56) and Cerdocyon thous (n = 46) collected between 2006 and 2012 were used. The nucleotide sequences obtained for the N gene of rabies virus were analyzed, and phylogenetic analysis revealed the presence of two distinct genetic lineages, one associated with canids and one with bats, and, within the canid cluster, two distinct sublineages circulating among dogs and Cerdocyon thous. In addition, phylogenetic groups associated with geographic region and fourteen cases of interspecific infection were observed among the isolates from canids. Our findings show that analysis of rabies virus lineages isolated from reservoirs such as canids must be constantly evaluated because the mutation rate is high.

  6. Complete mitochondrial genomes of ancient canids suggest a European origin of domestic dogs.

    Science.gov (United States)

    Thalmann, O; Shapiro, B; Cui, P; Schuenemann, V J; Sawyer, S K; Greenfield, D L; Germonpré, M B; Sablin, M V; López-Giráldez, F; Domingo-Roura, X; Napierala, H; Uerpmann, H-P; Loponte, D M; Acosta, A A; Giemsch, L; Schmitz, R W; Worthington, B; Buikstra, J E; Druzhkova, A; Graphodatsky, A S; Ovodov, N D; Wahlberg, N; Freedman, A H; Schweizer, R M; Koepfli, K-P; Leonard, J A; Meyer, M; Krause, J; Pääbo, S; Green, R E; Wayne, R K

    2013-11-15

    The geographic and temporal origins of the domestic dog remain controversial, as genetic data suggest a domestication process in East Asia beginning 15,000 years ago, whereas the oldest doglike fossils are found in Europe and Siberia and date to >30,000 years ago. We analyzed the mitochondrial genomes of 18 prehistoric canids from Eurasia and the New World, along with a comprehensive panel of modern dogs and wolves. The mitochondrial genomes of all modern dogs are phylogenetically most closely related to either ancient or modern canids of Europe. Molecular dating suggests an onset of domestication there 18,800 to 32,100 years ago. These findings imply that domestic dogs are the culmination of a process that initiated with European hunter-gatherers and the canids with whom they interacted.

  7. UV Continuum Slope and Dust Obscuration from z ~ 6 to z ~ 2: The Star Formation Rate Density at High Redshift

    Science.gov (United States)

    Bouwens, R. J.; Illingworth, G. D.; Franx, M.; Chary, R.-R.; Meurer, G. R.; Conselice, C. J.; Ford, H.; Giavalisco, M.; van Dokkum, P.

    2009-11-01

    We provide a systematic measurement of the rest-frame UV continuum slope β over a wide range in redshift (z ~ 2-6) and rest-frame UV luminosity (0.1 L* z = 3 to 2 L* z = 3) to improve estimates of the star formation rate (SFR) density at high redshift. We utilize the deep optical and infrared data (Advanced Camera for Surveys/NICMOS) over the Chandra Deep Field-South and Hubble Deep Field-North Great Observatories Origins Deep Survey fields, as well as the UDF for our primary UBVi "dropout" Lyman Break Galaxy sample. We also use strong lensing clusters to identify a population of very low luminosity, high-redshift dropout galaxies. We correct the observed distributions for both selection biases and photometric scatter. We find that the UV-continuum slope of the most luminous galaxies is substantially redder at z ~ 2-4 than it is at z ~ 5-6 (from ~-2.4 at z ~ 6 to ~-1.5 at z ~ 2). Lower luminosity galaxies are also found to be bluer than higher luminosity galaxies at z ~ 2.5 and z ~ 4. We do not find a large number of galaxies with β's as red as -1 in our dropout selections at z ~ 4, and particularly at z gsim 5, even though such sources could be readily selected from our data (and also from Balmer Break Galaxy searches at z ~ 4). This suggests that star-forming galaxies at z gsim 5 almost universally have very blue UV-continuum slopes, and that there are not likely to be a substantial number of dust-obscured galaxies at z gsim 5 that are missed in "dropout" searches. Using the same relation between UV-continuum slope and dust extinction as has been found to be appropriate at both z ~ 0 and z ~ 2, we estimate the average dust extinction of galaxies as a function of redshift and UV luminosity in a consistent way. As expected, we find that the estimated dust extinction increases substantially with cosmic time for the most UV luminous galaxies, but remains small (lsim2 times) at all times for lower luminosity galaxies. Because these same lower luminosity galaxies

  8. GRB 120521C at z ∼ 6 and the properties of high-redshift γ-ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Laskar, Tanmoy; Berger, Edo; Zauderer, B. Ashley; Margutti, Raffaella; Fong, Wen-fai [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Tanvir, Nial; Wiersema, Klaas [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Levan, Andrew [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Perley, Daniel [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Menten, Karl [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Hrudkova, Marie [Isaac Newton Group of Telescopes, Apartado de Correos 321, E-387 00 Santa Cruz de la Palma, Canary Islands (Spain)

    2014-01-20

    We present optical, near-infrared, and radio observations of the afterglow of GRB 120521C. By modeling the multi-wavelength data set, we derive a photometric redshift of z ≈ 6.0, which we confirm with a low signal-to-noise ratio spectrum of the afterglow. We find that a model with a constant-density environment provides a good fit to the afterglow data, with an inferred density of n ≲ 0.05 cm{sup –3}. The radio observations reveal the presence of a jet break at t {sub jet} ≈ 7 d, corresponding to a jet opening angle of θ{sub jet} ≈ 3°. The beaming-corrected γ-ray and kinetic energies are E {sub γ} ≈ E{sub K} ≈ 3 × 10{sup 50} erg. We quantify the uncertainties in our results using a detailed Markov Chain Monte Carlo analysis, which allows us to uncover degeneracies between the physical parameters of the explosion. To compare GRB 120521C to other high-redshift bursts in a uniform manner we re-fit all available afterglow data for the two other bursts at z ≳ 6 with radio detections (GRBs 050904 and 090423). We find a jet break at t {sub jet} ≈ 15 d for GRB 090423, in contrast to previous work. Based on these three events, we find that γ-ray bursts (GRBs) at z ≳ 6 appear to explode in constant-density environments, and exhibit a wide range of energies and densities that span the range inferred for lower redshift bursts. On the other hand, we find a hint for narrower jets in the z ≳ 6 bursts, potentially indicating a larger true event rate at these redshifts. Overall, our results indicate that long GRBs share a common progenitor population at least to z ∼ 8.

  9. Investigating the properties of gamma ray bursts and gravitational wave standard sirens as high redshift distance indicators

    Science.gov (United States)

    Speirits, Fiona Claire

    In a discipline commonly faulted for ad hoc assumptions and models with very little discriminating observational evidence, cosmologists are continually trying, and in many cases succeeding, to improve both the data and models. However, the desire to support currently favoured models often dominates research and may lead to a systematic bias being introduced in favour of a model before a strong body of supporting evidence has been accumulated. This is perhaps most evident in literature supporting the viability of Gamma Ray Bursts as cosmological distance indicators, where aside from subjective data-selection, the basic statistical methods are at best questionable and at worst incorrect. To this end, we construct a simple cosmology-independent illustration of the effect that the application of these methods has on parameter estimation and discuss the correct method to apply to current data. We also investigate the constraints potential future Gamma Ray Burst data may place on alternatives to the status quo Concordance Model in the shape of Conformal Gravity and Unified Dark Matter through a widely applicable and transferable Bayesian model comparison technique and the development of a representative mock data set. Finally, we investigate gravitational wave standard sirens as an alternative high-redshift distance indicator. We first illustrate their strong diagnostic potential through a Bayesian model comparison between the standard Unified Dark Matter model and a variant in which the dark component is redshift dependent. By drawing mock data from a known cosmological model, thus fixing the expected values of the model parameters, we find that while 182 Type 1a Supernovae are readily confused between constant and evolving models, just 2 standard sirens are able to successfully identify the correct model. Having established standard sirens as an effective tool in cosmological model comparison, we then address the potential confusion of models with dynamical dark energy

  10. Properties of z ~ 3-6 Lyman break galaxies. II. Impact of nebular emission at high redshift

    Science.gov (United States)

    de Barros, S.; Schaerer, D.; Stark, D. P.

    2014-03-01

    Context. To gain insight on the mass assembly and place constraints on the star formation history (SFH) of Lyman break galaxies (LBGs), it is important to accurately determine their properties. Aims: We estimate how nebular emission and different SFHs affect parameter estimation of LBGs. Methods: We present a homogeneous, detailed analysis of the spectral energy distribution (SED) of ~1700 LBGs from the GOODS-MUSIC catalogue with deep multi-wavelength photometry from the U band to 8 μm to determine stellar mass, age, dust attenuation, and star formation rate. Using our SED fitting tool, which takes into account nebular emission, we explore a wide parameter space. We also explore a set of different star formation histories. Results: Nebular emission is found to significantly affect the determination of the physical parameters for the majority of z ~ 3-6 LBGs. We identify two populations of galaxies by determining the importance of the contribution of emission lines to broadband fluxes. We find that ~65% of LBGs show detectable signs of emission lines, whereas ~35% show weak or no emission lines. This distribution is found over the entire redshift range. We interpret these groups as actively star-forming and more quiescent LBGs, respectively. We find that it is necessary to considerer SED fits with very young ages (affected by strong emission lines. Other arguments favouring episodic star formation and relatively short star formation timescales are also discussed. Considering nebular emission generally leads to a younger age, lower stellar mass, higher dust attenuation, higher star formation rate, and a large scatter in the SFR-M⋆ relation. Our analysis yields a trend of increasing specific star formation rate with redshift, as predicted by recent galaxy evolution models. Conclusions: The physical parameters of approximately two thirds of high redshift galaxies are significantly modified when we account for nebular emission. The SED models, which include nebular

  11. High-redshift AGN in the Chandra Deep Fields: the obscured fraction and space density of the sub-L* population

    Science.gov (United States)

    Vito, F.; Brandt, W. N.; Yang, G.; Gilli, R.; Luo, B.; Vignali, C.; Xue, Y. Q.; Comastri, A.; Koekemoer, A. M.; Lehmer, B. D.; Liu, T.; Paolillo, M.; Ranalli, P.; Schneider, D. P.; Shemmer, O.; Volonteri, M.; Wang, J.

    2018-01-01

    We investigate the population of high-redshift (3 ≤ z Deep Field-South and 2 Ms Chandra Deep Field-North. Their outstanding sensitivity and spectral characterization of faint sources allow us to focus on the sub-L* regime (logLX ≲ 44), poorly sampled by previous works using shallower data, and the obscured population. Taking fully into account the individual photometric-redshift probability distribution functions, the final sample consists of ≈102 X-ray-selected AGN at 3 ≤ z 23 is ∼0.6-0.8, once incompleteness effects are taken into account, with no strong dependence on redshift or luminosity. We derived the high-redshift AGN number counts down to F0.5-2 keV = 7 × 10-18 erg cm-2 s-1, extending previous results to fainter fluxes, especially at z > 4. We put the tightest constraints to date on the low-luminosity end of AGN luminosity function at high redshift. The space density, in particular, declines at z > 3 at all luminosities, with only a marginally steeper slope for low-luminosity AGN. By comparing the evolution of the AGN and galaxy densities, we suggest that such a decline at high luminosities is mainly driven by the underlying galaxy population, while at low luminosities there are hints of an intrinsic evolution of the parameters driving nuclear activity. Also, the black hole accretion rate density and star formation rate density, which are usually found to evolve similarly at z ≲ 3, appear to diverge at higher redshifts.

  12. Ancient DNA analysis affirms the canid from Altai as a primitive dog.

    Directory of Open Access Journals (Sweden)

    Anna S Druzhkova

    Full Text Available The origin of domestic dogs remains controversial, with genetic data indicating a separation between modern dogs and wolves in the Late Pleistocene. However, only a few dog-like fossils are found prior to the Last Glacial Maximum, and it is widely accepted that the dog domestication predates the beginning of agriculture about 10,000 years ago. In order to evaluate the genetic relationship of one of the oldest dogs, we have isolated ancient DNA from the recently described putative 33,000-year old Pleistocene dog from Altai and analysed 413 nucleotides of the mitochondrial control region. Our analyses reveal that the unique haplotype of the Altai dog is more closely related to modern dogs and prehistoric New World canids than it is to contemporary wolves. Further genetic analyses of ancient canids may reveal a more exact date and centre of domestication.

  13. The origin of the lower fourth molar in canids, inferred by individual variation

    Directory of Open Access Journals (Sweden)

    Masakazu Asahara

    2016-11-01

    Full Text Available Background An increase in tooth number is an exception during mammalian evolution. The acquisition of the lower fourth molar in the bat-eared fox (Otocyon megalotis, Canidae, Carnivora, Mammalia is one example; however, its developmental origin is not clear. In some canids (Canidae, individual variation exist as supernumerary molar M4. This study focuses on the acquisition of the lower fourth molar in canids and proposes that the inhibitory cascade model can explain its origin. Methods Occlusal view projected area of lower molars was determined from 740 mandibles obtained from Canis latrans, Nyctereutes procyonoides, and Urocyon cinereoargenteus museum specimens. For each molar, relative sizes of molars (M2/M1 and M3/M1 scores affected by inhibition/activation dynamics during development, were compared between individuals with and without supernumerary molar (M4. Results Possession of a supernumerary molar was associated with significantly larger M2/M1 score in Canis latrans, M3/M1 score in Nyctereutes procyonoides, and M2/M1 and M3/M1 scores in Urocyon cinereoargenteus compared to individuals of these species that lacked supernumerary molars. Discussion We propose that, in canids, the supernumerary fourth molar is attributable to reduced inhibition and greater activation during molar development. In the bat-eared fox, altered inhibition and activation dynamics of dental development during omnivorous-insectivorous adaptation may be a contributing factor in the origin of the lower fourth molar.

  14. Epidemiological study of gastrointestinal helminthes of canids in chaharmahal and bakhtiari province of iran.

    Directory of Open Access Journals (Sweden)

    Reza Nabavi

    2014-06-01

    Full Text Available The present study was carried out to describe the epidemiological aspects of gastrointestinal helminthic infections of canids in Chaharmahal and Bakhtiari Province, the central western part of Iran.Forty nine canid species including, dogs, jackals, foxes and wolves were included in this study. The contents of their alimentary canal were inspected in order to isolate and identify the parasitic helminthes of this system. To identify the worms, the Soulsbey and Anderson identification key and light microscopy were used.Based on necropsy findings, 35 (71.4% of examined animals were infected with at least one helminth. The prevalence of identified worms was as follows: Mesocestoides lineatus (55.1%, Joyeuxiella echinorinchoides (26.5%, Taenia hydatigena (12.2%, T. multiceps (8.2%, T. ovis (2%, Dipylidium caninum (2% and Spirura spp. (2%. No significant difference was noticed between the sampling areas, age and helminth infection. Only a significant difference was observed for prevalence of T. multiceps in wolf (25%, dog (21.4%, jackal and fox (0%, respectively (P < 0.05.The canids in Chaharmahal and Bakhtiari harbor several parasites that some kind of them have zoonotic importance and may pose a threat to community health specially in rural areas.

  15. X-Ray Temperatures for the Extended Medium-Sensitivity Survey High-Redshift Cluster Sample: Constraints on Cosmology and the Dark Energy Equation of State

    Science.gov (United States)

    Henry, J. Patrick

    2004-07-01

    We measure the X-ray temperature (and luminosity) with ASCA of all but one cluster in the Einstein Extended Medium-Sensitivity Survey (EMSS) high-redshift (z>=0.3) sample. We compare these data to a complete sample of low-redshift clusters that also has temperature measurements, thereby providing cosmological constraints. Improvements over our previous work include (1) an enlarged high-redshift sample; (2) temperatures for the low-redshift comparison sample that come from the same instrument as the high-redshift sample; (3) the elimination of three EMSS clusters with the same redshift as the target (i.e., not truly serendipitous) and a fourth with an ASCA flux well below the completeness limit; (4) using a theoretical cluster mass function that more closely matches N-body simulations (the Sheth-Torman function); (5) using a cold dark matter power spectrum instead of a power law; (6) using a general cosmology with arbitrary matter density and cosmological constant; (7) using a cosmology that generalizes the cosmological constant to quintessence; (8) including the effects of temperature measurement errors and scatter in the cluster luminosity-temperature relation; and (9) marginalizing over the poorly known normalization of the mass-temperature relation. We find an allowed band in the Ωm0-ΩΛ0 plane of different orientation to the band of constraints provided by the supernovae Ia Hubble diagram and the cosmic microwave background fluctuations. All three bands intersect at the same place: Ωm0~0.3, ΩΛ0~0.7. We measure the quintessence equation-of-state parameter to be w=-(0.42+/-0.21) (68% confidence for one interesting parameter), consistent with previously determined upper limits. We measure the normalization of the mass fluctuation power spectrum to be σ8=0.66+/-0.16 (68% confidence for three interesting parameters). Systematic errors are larger than the statistical errors only for σ8 with our sample; thus the errors for it depend on the details of the

  16. Ancient DNA analysis of the oldest canid species from the Siberian Arctic and genetic contribution to the domestic dog.

    Directory of Open Access Journals (Sweden)

    Esther J Lee

    Full Text Available Modern Arctic Siberia provides a wealth of resources for archaeological, geological, and paleontological research to investigate the population dynamics of faunal communities from the Pleistocene, particularly as the faunal material coming from permafrost has proven suitable for genetic studies. In order to examine the history of the Canid species in the Siberian Arctic, we carried out genetic analysis of fourteen canid remains from various sites, including the well-documented Upper Paleolithic Yana RHS and Early Holocene Zhokhov Island sites. Estimated age of samples range from as recent as 1,700 years before present (YBP to at least 360,000 YBP for the remains of the extinct wolf, Canis cf. variabilis. In order to examine the genetic affinities of ancient Siberian canids species to the domestic dog and modern wolves, we obtained mitochondrial DNA control region sequences and compared them to published ancient and modern canid sequences. The older canid specimens illustrate affinities with pre-domestic dog/wolf lineages while others appear in the major phylogenetic clades of domestic dogs. Our results suggest a European origin of domestic dog may not be conclusive and illustrates an emerging complexity of genetic contribution of regional wolf breeds to the modern Canis gene pool.

  17. High-redshift Galaxies and Black Holes Detectable with the JWST: A Population Synthesis Model from Infrared to X-Rays

    Science.gov (United States)

    Volonteri, Marta; Reines, Amy E.; Atek, Hakim; Stark, Daniel P.; Trebitsch, Maxime

    2017-11-01

    The first billion years of the Universe has been a pivotal time: stars, black holes (BHs), and galaxies formed and assembled, sowing the seeds of galaxies as we know them today. Detecting, identifying, and understanding the first galaxies and BHs is one of the current observational and theoretical challenges in galaxy formation. In this paper we present a population synthesis model aimed at galaxies, BHs, and active galactic nuclei (AGNs) at high redshift. The model builds a population based on empirical relations. The spectral energy distribution of galaxies is determined by age and metallicity, and that of AGNs by BH mass and accretion rate. We validate the model against observations, and predict properties of galaxies and AGN in other wavelength and/or luminosity ranges, estimating the contamination of stellar populations (normal stars and high-mass X-ray binaries) for AGN searches from the infrared to X-rays, and vice versa for galaxy searches. For high-redshift galaxies with stellar ages < 1 {Gyr}, we find that disentangling stellar and AGN emission is challenging at restframe UV/optical wavelengths, while high-mass X-ray binaries become more important sources of confusion in X-rays. We propose a color–color selection in the James Webb Space Telescope bands to separate AGN versus star-dominated galaxies in photometric observations. We also estimate the AGN contribution, with respect to massive, hot, and metal-poor stars, at driving high-ionization lines, such as C iv and He ii. Finally, we test the influence of the minimum BH mass and occupation fraction of BHs in low-mass galaxies on the restframe UV/near-IR and X-ray AGN luminosity function.

  18. Candidatus Bartonella merieuxii, a potential new zoonotic Bartonella species in canids from Iraq.

    Directory of Open Access Journals (Sweden)

    Bruno B Chomel

    Full Text Available Bartonellae are emerging vector-borne pathogens infecting erythrocytes and endothelial cells of various domestic and wild mammals. Blood samples were collected from domestic and wild canids in Iraq under the United States Army zoonotic disease surveillance program. Serology was performed using an indirect immunofluorescent antibody test for B. henselae, B. clarridgeiae, B. vinsonii subsp. berkhoffii and B. bovis. Overall seroprevalence was 47.4% in dogs (n = 97, 40.4% in jackals (n = 57 and 12.8% in red foxes (n = 39. Bartonella species DNA was amplified from whole blood and representative strains were sequenced. DNA of a new Bartonella species similar to but distinct from B. bovis, was amplified from 37.1% of the dogs and 12.3% of the jackals. B. vinsonii subsp. berkhoffii was also amplified from one jackal and no Bartonella DNA was amplified from foxes. Adjusting for age, the odds of dogs being Bartonella PCR positive were 11.94 times higher than for wild canids (95% CI: 4.55-31.35, suggesting their role as reservoir for this new Bartonella species. This study reports on the prevalence of Bartonella species in domestic and wild canids of Iraq and provides the first detection of Bartonella in jackals. We propose Candidatus Bartonella merieuxii for this new Bartonella species. Most of the Bartonella species identified in sick dogs are also pathogenic for humans. Therefore, seroprevalence in Iraqi dog owners and bacteremia in Iraqi people with unexplained fever or culture negative endocarditis requires further investigation as well as in United States military personnel who were stationed in Iraq. Finally, it will also be essential to test any dog brought back from Iraq to the USA for presence of Bartonella bacteremia to prevent any accidental introduction of a new Bartonella species to the New World.

  19. Unraveling the key to the resistance of canids to prion diseases.

    Directory of Open Access Journals (Sweden)

    Natalia Fernández-Borges

    2017-11-01

    Full Text Available One of the characteristics of prions is their ability to infect some species but not others and prion resistant species have been of special interest because of their potential in deciphering the determinants for susceptibility. Previously, we developed different in vitro and in vivo models to assess the susceptibility of species that were erroneously considered resistant to prion infection, such as members of the Leporidae and Equidae families. Here we undertake in vitro and in vivo approaches to understand the unresolved low prion susceptibility of canids. Studies based on the amino acid sequence of the canine prion protein (PrP, together with a structural analysis in silico, identified unique key amino acids whose characteristics could orchestrate its high resistance to prion disease. Cell- and brain-based PMCA studies were performed highlighting the relevance of the D163 amino acid in proneness to protein misfolding. This was also investigated by the generation of a novel transgenic mouse model carrying this substitution and these mice showed complete resistance to disease despite intracerebral challenge with three different mouse prion strains (RML, 22L and 301C known to cause disease in wild-type mice. These findings suggest that dog D163 amino acid is primarily, if not totally, responsible for the prion resistance of canids.

  20. A genome-wide perspective on the evolutionary history of enigmatic wolf-like canids

    Science.gov (United States)

    vonHoldt, Bridgett M.; Pollinger, John P.; Earl, Dent A.; Knowles, James C.; Boyko, Adam R.; Parker, Heidi; Geffen, Eli; Pilot, Malgorzata; Jedrzejewski, Wlodzimierz; Jedrzejewska, Bogumila; Sidorovich, Vadim; Greco, Claudia; Randi, Ettore; Musiani, Marco; Kays, Roland; Bustamante, Carlos D.; Ostrander, Elaine A.; Novembre, John; Wayne, Robert K.

    2011-01-01

    High-throughput genotyping technologies developed for model species can potentially increase the resolution of demographic history and ancestry in wild relatives. We use a SNP genotyping microarray developed for the domestic dog to assay variation in over 48K loci in wolf-like species worldwide. Despite the high mobility of these large carnivores, we find distinct hierarchical population units within gray wolves and coyotes that correspond with geographic and ecologic differences among populations. Further, we test controversial theories about the ancestry of the Great Lakes wolf and red wolf using an analysis of haplotype blocks across all 38 canid autosomes. We find that these enigmatic canids are highly admixed varieties derived from gray wolves and coyotes, respectively. This divergent genomic history suggests that they do not have a shared recent ancestry as proposed by previous researchers. Interspecific hybridization, as well as the process of evolutionary divergence, may be responsible for the observed phenotypic distinction of both forms. Such admixture complicates decisions regarding endangered species restoration and protection. PMID:21566151

  1. A Pathological Late Pleistocene canid from San Sidero (Italy): implications for social- and feeding-behaviour

    Science.gov (United States)

    Iurino, Dawid Adam; Fico, Rosario; Petrucci, Mauro; Sardella, Raffaele

    2013-03-01

    Evidence of diseases on vertebrate fossil bones can provide detailed information on many aspects of extinct animals. This study focused on pathological craniodental remains (left maxilla and dentary) referred to the canid Cuon alpinus unearthed from a Late Pleistocene karst filling deposit at San Sidero (Apulia, southern Italy). These fossils show clear evidence of a chronic periodontitis that caused the animal's death. Clinical diagnosis of the disease and the timing of its development have been defined on the basis of a veterinary odontostomatology approach, in addition to radiographic and tomographic techniques. From the initiation of the infection until death, a time span of at least 6 months occurred, and three main steps have been defined: (1) the bacterial infections of the buccal cavity turning into severe periodontitis, (2) the fracture of the lower carnassial and (3) the loss of teeth due to the worsening infection that deformed and/or eroded maxillary and mandibular bones and enlarged alveoli. The analysis of the palaeopathology also provides information about the biomechanics of the bite, on the feeding behaviour and on the relationships of injured members in a pack of Late Pleistocene canids.

  2. GOODS-HERSCHEL MEASUREMENTS OF THE DUST ATTENUATION OF TYPICAL STAR-FORMING GALAXIES AT HIGH REDSHIFT: OBSERVATIONS OF ULTRAVIOLET-SELECTED GALAXIES AT z {approx} 2

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, N.; Dickinson, M.; Kartaltepe, J. [National Optical Astronomy Observatory, 950 N Cherry Ave, Tucson, AZ 85719 (United States); Elbaz, D.; Daddi, E.; Magdis, G.; Aussel, H.; Dannerbauer, H.; Dasyra, K.; Hwang, H. S. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Universite Paris Diderot, CE-Saclay, F-91191, Gif-sur-Yvette (France); Morrison, G. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Giavalisco, M. [Astronomy Department, University of Massachusetts, Amherst, Amherst, MA 01003 (United States); Ivison, R. [UK Astronomy Technology Centre, Science and Technology Facilities Council, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Papovich, C. [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77845 (United States); Scott, D. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Buat, V.; Burgarella, D. [Laboratoire d' Astrophysique de Marseille, OAMP, Universite Aix-Marseille, CNRS, 38 Rue Frederic Joliot-Curie, 13388 Marseille Cedex 13 (France); Charmandaris, V. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003, Heraklion (Greece); Murphy, E. [Spitzer Science Center, MC 314-6, California Institute of Technology, Pasadena, CA 91125 (United States); Altieri, B. [Herschel Science Centre, European Space Astronomy Centre, Villanueva de la Canada, 28691 Madrid (Spain); and others

    2012-01-10

    We take advantage of the sensitivity and resolution of the Herschel Space Observatory at 100 and 160 {mu}m to directly image the thermal dust emission and investigate the infrared luminosities (L{sub IR}) and dust obscuration of typical star-forming (L*) galaxies at high redshift. Our sample consists of 146 UV-selected galaxies with spectroscopic redshifts 1.5 {<=} z{sub spec} < 2.6 in the GOODS-North field. Supplemented with deep Very Large Array and Spitzer imaging, we construct median stacks at the positions of these galaxies at 24, 100, and 160 {mu}m, and 1.4 GHz. The comparison between these stacked fluxes and a variety of dust templates and calibrations implies that typical star-forming galaxies with UV luminosities L{sub UV} {approx}> 10{sup 10} L{sub Sun} at z {approx} 2 are luminous infrared galaxies with a median L{sub IR} = (2.2 {+-} 0.3) Multiplication-Sign 10{sup 11} L{sub Sun }. Their median ratio of L{sub IR} to rest-frame 8 {mu}m luminosity (L{sub 8}) is L{sub IR}/L{sub 8} = 8.9 {+-} 1.3 and is Almost-Equal-To 80% larger than that found for most star-forming galaxies at z {approx}< 2. This apparent redshift evolution in the L{sub IR}/L{sub 8} ratio may be tied to the trend of larger infrared luminosity surface density for z {approx}> 2 galaxies relative to those at lower redshift. Typical galaxies at 1.5 {<=} z < 2.6 have a median dust obscuration L{sub IR}/L{sub UV} = 7.1 {+-} 1.1, which corresponds to a dust correction factor, required to recover the bolometric star formation rate (SFR) from the unobscured UV SFR, of 5.2 {+-} 0.6. This result is similar to that inferred from previous investigations of the UV, H{alpha}, 24 {mu}m, radio, and X-ray properties of the same galaxies studied here. Stacking in bins of UV slope ({beta}) implies that L* galaxies with redder spectral slopes are also dustier and that the correlation between {beta} and dustiness is similar to that found for local starburst galaxies. Hence, the rest-frame {approx_equal} 30 and

  3. Infrared-faint radio sources are at high redshifts. Spectroscopic redshift determination of infrared-faint radio sources using the Very Large Telescope

    Science.gov (United States)

    Herzog, A.; Middelberg, E.; Norris, R. P.; Sharp, R.; Spitler, L. R.; Parker, Q. A.

    2014-07-01

    Context. Infrared-faint radio sources (IFRS) are characterised by relatively high radio flux densities and associated faint or even absent infrared and optical counterparts. The resulting extremely high radio-to-infrared flux density ratios up to several thousands were previously known only for high-redshift radio galaxies (HzRGs), suggesting a link between the two classes of object. However, the optical and infrared faintness of IFRS makes their study difficult. Prior to this work, no redshift was known for any IFRS in the Australia Telescope Large Area Survey (ATLAS) fields which would help to put IFRS in the context of other classes of object, especially of HzRGs. Aims: This work aims at measuring the first redshifts of IFRS in the ATLAS fields. Furthermore, we test the hypothesis that IFRS are similar to HzRGs, that they are higher-redshift or dust-obscured versions of these massive galaxies. Methods: A sample of IFRS was spectroscopically observed using the Focal Reducer and Low Dispersion Spectrograph 2 (FORS2) at the Very Large Telescope (VLT). The data were calibrated based on the Image Reduction and Analysis Facility (IRAF) and redshifts extracted from the final spectra, where possible. This information was then used to calculate rest-frame luminosities, and to perform the first spectral energy distribution modelling of IFRS based on redshifts. Results: We found redshifts of 1.84, 2.13, and 2.76, for three IFRS, confirming the suggested high-redshift character of this class of object. These redshifts and the resulting luminosities show IFRS to be similar to HzRGs, supporting our hypothesis. We found further evidence that fainter IFRS are at even higher redshifts. Conclusions: Considering the similarities between IFRS and HzRGs substantiated in this work, the detection of IFRS, which have a significantly higher sky density than HzRGs, increases the number of active galactic nuclei in the early universe and adds to the problems of explaining the formation of

  4. Effect of primordial non-Gaussianities on the far-UV luminosity function of high-redshift galaxies: implications for cosmic reionization

    Science.gov (United States)

    Chevallard, Jacopo; Silk, Joseph; Nishimichi, Takahiro; Habouzit, Melanie; Mamon, Gary A.; Peirani, Sébastien

    2015-01-01

    Understanding how the intergalactic medium (IGM) was reionized at z ≳ 6 is one of the big challenges of current high-redshift astronomy. It requires modelling the collapse of the first astrophysical objects (Pop III stars, first galaxies) and their interaction with the IGM, while at the same time pushing current observational facilities to their limits. The observational and theoretical progress of the last few years have led to the emergence of a coherent picture in which the budget of hydrogen-ionizing photons is dominated by low-mass star-forming galaxies, with little contribution from Pop III stars and quasars. The reionization history of the Universe therefore critically depends on the number density of low-mass galaxies at high redshift. In this work, we explore how changes in the cosmological model, and in particular in the statistical properties of initial density fluctuations, affect the formation of early galaxies. Following Habouzit et al. (2014), we run five different N-body simulations with Gaussian and (scale-dependent) non-Gaussian initial conditions, all consistent with Planck constraints. By appealing to a phenomenological galaxy formation model and to a population synthesis code, we compute the far-UV galaxy luminosity function down to MFUV = -14 at redshift 7 ≤ z ≤ 15. We find that models with strong primordial non-Gaussianities on ≲ Mpc scales show a far-UV luminosity function significantly enhanced (up to a factor of 3 at z = 14) in low-mass galaxies. We adopt a reionization model calibrated from state-of-the-art hydrodynamical simulations and show that such scale-dependent non-Gaussianities leave a clear imprint on the Universe reionization history and electron Thomson scattering optical depth τe. Although current uncertainties in the physics of reionization and on the determination of τe still dominate the signatures of non-Gaussianities, our results suggest that τe could ultimately be used to constrain the statistical properties

  5. Planck intermediate results XXVII. High-redshift infrared galaxy overdensity candidates and lensed sources discovered by Planck and confirmed by Herschel-SPIRE⋆

    DEFF Research Database (Denmark)

    Aghanim, N.; Altieri, B.; Arnaud, M.

    2015-01-01

    We have used the Planck all-sky submillimetre and millimetre maps to search for rare sources distinguished by extreme brightness, a few hundred millijanskies, and their potential for being situated at high redshift. These "cold" Planck sources, selected using the High Frequency Instrument (HFI) d...

  6. Swift multi-wavelength observations of the high-redshift Blazar S5 0836+710 (4C 71.07)

    Science.gov (United States)

    Vercellone, Stefano; Romano, Patrizia; Raiteri, Claudia Maria; Acosta Pulido, Jose; Villata, Massimo; Carnerero Martin, Maria Isabel

    2016-04-01

    We present the preliminary results of a year-long Swift monitoring campaign of the high-redshift (z=2.172) flat-spectrum radio quasar (FSRQ) S5 0836+710 (4C 71.07). The campaign, based on one observation per month, 5 ks each observation, for 12 months, allowed us to investigate the synchrotron and nuclear emission contributions to the optical-UV frequency range of its spectral energy distribution and the X-ray spectral variations along a baseline of a year. We obtained a high-accuracy determination of UVOT magnitudes, an X-ray photon index with an uncertainty of the order of 5%, and well-sampled light curves both in the optical-UV and X-ray energy bands to study their possible modulations and correlations. Our study allowed us to exploit the unique Swift capabilities in terms of both simultaneous energy coverage and schedule flexibility. The Swift monitoring campaign was supported by observations by the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT) Collaboration, which provided radio, near-infrared, and optical photometric data as well as optical polarimetry. Moreover, a spectroscopic monitoring was obtained at the William Herschel Telescope (WHT) and the Nordic Optical Telescope (NOT). All these observations will allow us to obtain a comprehensive picture of the jet as well as of the nuclear source emission.

  7. Dark-ages reionization and galaxy formation simulation - XIII. AGN quenching of high-redshift star formation in ZF-COSMOS-20115

    Science.gov (United States)

    Qin, Yuxiang; Mutch, Simon J.; Duffy, Alan R.; Geil, Paul M.; Poole, Gregory B.; Mesinger, Andrei; Wyithe, J. Stuart B.

    2017-11-01

    Massive quiescent galaxies (MQGs) are thought to have formed stars rapidly at early times followed by a long period of quiescence. The recent discovery of a MQG, ZF-COSMOS-20115 at z ˜ 4, only 1.5 Gyr after the big bang, places new constraints on galaxy growth and the role of feedback in early star formation. Spectroscopic follow-up confirmed ZF-COSMOS-20115 as a MQG at z = 3.717 with an estimated stellar mass of ˜1011 M⊙, showing no evidence of recent star formation. We use the Meraxes semi-analytic model to investigate how ZF-COSMOS-20115 analogues build stellar mass, and why they become quiescent. We identify three analogue galaxies with similar properties to ZF-COSMOS-20115. We find that ZF-COSMOS-20115 is likely hosted by a massive halo with virial mass of ˜1013 M⊙, having been through significant mergers at early times. These merger events drove intense growth of the nucleus, which later prevented cooling and quenched star formation. Therefore, ZF-COSMOS-20115 is unlikely to have experienced strong or extended star formation events at z black holes in our simulation and were luminous quasars at z ˜ 5, indicating that ZF-COSMOS-20115 and other MQGs may be the descendants of high-redshift quasars. In addition, the model suggests that ZF-COSMOS-20115 formed in a region of intergalactic medium that was reionized early.

  8. Red galaxies at high redshift

    NARCIS (Netherlands)

    Wuyts, Stijn Elisabeth Raphaël

    2007-01-01

    From its origin at the center of a star to the edge, through the surrounding gas and dust in the distant galaxy, through the intergalactic medium, traveling billions of light years only to be reflected by a mirror and captured by a detector; the little amount of light observed from galaxies in the

  9. Lessons from a non-domestic canid: joint disease in captive raccoon dogs (Nyctereutes procyonoides).

    Science.gov (United States)

    Lawler, Dennis F; Evans, Richard H; Nieminen, Petteri; Mustonen, Anne-Mari; Smith, Gail K

    2012-01-01

    The purpose of this study was to describe pathological changes of the shoulder, elbow, hip and stifle joints of 16 museum skeletons of the raccoon dog (Nyctereutes procyonoides). The subjects had been held in long-term captivity and were probably used for fur farming or research, thus allowing sufficient longevity for joint disease to become recognisable. The prevalence of disorders that include osteochondrosis, osteoarthritis and changes compatible with hip dysplasia, was surprisingly high. Other changes that reflect near-normal or mild pathological conditions, including prominent articular margins and mild bony periarticular rim, were also prevalent. Our data form a basis for comparing joint pathology of captive raccoon dogs with other mammals and also suggest that contributing roles of captivity and genetic predisposition should be explored further in non-domestic canids.

  10. Lessons from a non-domestic canid: joint disease in captive raccoon dogs (Nyctereutes procyonoides

    Directory of Open Access Journals (Sweden)

    Dennis F. Lawler

    2012-12-01

    Full Text Available The purpose of this study was to describe pathological changes of the shoulder, elbow, hip and stifle joints of 16 museum skeletons of the raccoon dog (Nyctereutes procyonoides. The subjects had been held in long-term captivity and were probably used for fur farming or research, thus allowing sufficient longevity for joint disease to become recognisable. The prevalence of disorders that include osteochondrosis, osteoarthritis and changes compatible with hip dysplasia, was surprisingly high. Other changes that reflect near-normal or mild pathological conditions, including prominent articular margins and mild bony periarticular rim, were also prevalent. Our data form a basis for comparing joint pathology of captive raccoon dogs with other mammals and also suggest that contributing roles of captivity and genetic predisposition should be explored further in non-domestic canids.

  11. Molecular characterization of Hepatozoon spp. infection in endangered Indian wild felids and canids.

    Science.gov (United States)

    Pawar, Rahul Mohanchandra; Poornachandar, Anantula; Srinivas, Pasham; Rao, Kancharapu Ramachandra; Lakshmikantan, Uthandaraman; Shivaji, Sisinthy

    2012-05-25

    Hepatozoon species are parasites that infect a wide variety of domestic and wild animals. The objective of this study was to perform the molecular detection and characterization of Hepatozoon spp. in Asiatic lion, Indian tiger, Indian leopard, Indian wild dog, Indian domestic dog and cat based on partial 18S rRNA gene sequences from Hepatozoon spp. in the naturally infected animals. Hepatozoon spp. could be detected in blood samples of 5 out of 9 Asiatic lions, 2 out of 5 Indian tigers, 2 out of 4 Indian leopards and 2 out of 2 Indian wild dogs and, 2 out of 4 domestic cats and 2 out of 3 domestic dog samples by PCR. Sequencing of PCR amplicon and BLAST analysis of partial 18S rRNA gene sequences indicated that the Hepatozoon spp. in Asiatic lion, Bengal tiger, Indian leopard and domestic cat was Hepatozoon felis (98-99% similarity) and in the Indian wild and domestic dog the phylogenetic neighbour was Hepatozoon canis (97-100% similarity). Presence of H. felis and H. canis in both domestic and wild animals suggested that they are not host specific and the same parasite causes infection in domestic and wild felids and canids in India and from different parts of the world. To our knowledge, this is the first report on detection and molecular characterization of H. felis infection in Asiatic lions, Indian tigers, Indian leopards and H. canis in Indian wild dog. Hepatozoon spp. may be a potential pathogen and an opportunistic parasite in immuno-compromised animals and could thus represent a threat to endangered Indian wild felids and canids. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. RadioAstron space VLBI imaging of polarized radio emission in the high-redshift quasar 0642+449 at 1.6 GHz

    Science.gov (United States)

    Lobanov, A. P.; Gómez, J. L.; Bruni, G.; Kovalev, Y. Y.; Anderson, J.; Bach, U.; Kraus, A.; Zensus, J. A.; Lisakov, M. M.; Sokolovsky, K. V.; Voytsik, P. A.

    2015-11-01

    Context. Polarization of radio emission in extragalactic jets at a sub-milliarcsecond angular resolution holds important clues for understanding the structure of the magnetic field in the inner regions of the jets and in close vicinity of the supermassive black holes in the centers of active galaxies. Aims: Space VLBI observations provide a unique tool for polarimetric imaging at a sub-milliarcsecond angular resolution and studying the properties of magnetic field in active galactic nuclei on scales of less than 104 gravitational radii. Methods: A space VLBI observation of high-redshift quasar TXS 0642+449 (OH 471), made at a wavelength of 18 cm (frequency of 1.6 GHz) as part of the early science programme (ESP) of the RadioAstron mission, is used here to test the polarimetric performance of the orbiting Space Radio Telescope (SRT) employed by the mission, to establish a methodology for making full Stokes polarimetry with space VLBI at 1.6 GHz, and to study the polarized emission in the target object on sub-milliarcsecond scales. Results: Polarization leakage of the SRT at 18 cm is found to be within 9% in amplitude, demonstrating the feasibility of high fidelity polarization imaging with RadioAstron at this wavelength. A polarimetric image of 0642+449 with a resolution of 0.8 mas (signifying an ~4 times improvement over ground VLBI observations at the same wavelength) is obtained. The image shows a compact core-jet structure with low (≈2%) polarization and predominantly transverse magnetic field in the nuclear region. The VLBI data also uncover a complex structure of the nuclear region, with two prominent features possibly corresponding to the jet base and a strong recollimation shock. The maximum brightness temperature at the jet base can be as high as 4 × 1013 K.

  13. Cluster Mass Calibration at High Redshift: HST Weak Lensing Analysis of 13 Distant Galaxy Clusters from the South Pole Telescope Sunyaev-Zel'dovich Survey

    Energy Technology Data Exchange (ETDEWEB)

    Schrabback, T.; et al.

    2016-11-11

    We present an HST/ACS weak gravitational lensing analysis of 13 massive high-redshift (z_median=0.88) galaxy clusters discovered in the South Pole Telescope (SPT) Sunyaev-Zel'dovich Survey. This study is part of a larger campaign that aims to robustly calibrate mass-observable scaling relations over a wide range in redshift to enable improved cosmological constraints from the SPT cluster sample. We introduce new strategies to ensure that systematics in the lensing analysis do not degrade constraints on cluster scaling relations significantly. First, we efficiently remove cluster members from the source sample by selecting very blue galaxies in V-I colour. Our estimate of the source redshift distribution is based on CANDELS data, where we carefully mimic the source selection criteria of the cluster fields. We apply a statistical correction for systematic photometric redshift errors as derived from Hubble Ultra Deep Field data and verified through spatial cross-correlations. We account for the impact of lensing magnification on the source redshift distribution, finding that this is particularly relevant for shallower surveys. Finally, we account for biases in the mass modelling caused by miscentring and uncertainties in the mass-concentration relation using simulations. In combination with temperature estimates from Chandra we constrain the normalisation of the mass-temperature scaling relation ln(E(z) M_500c/10^14 M_sun)=A+1.5 ln(kT/7.2keV) to A=1.81^{+0.24}_{-0.14}(stat.) +/- 0.09(sys.), consistent with self-similar redshift evolution when compared to lower redshift samples. Additionally, the lensing data constrain the average concentration of the clusters to c_200c=5.6^{+3.7}_{-1.8}.

  14. Serologic evidence of Leishmania infection in free-ranging wild and domestic canids around a Brazilian National Park.

    Science.gov (United States)

    Curi, Nelson Henrique de Almeida; Miranda, Ildikó; Talamoni, Sônia A

    2006-02-01

    Transmission of disease between wildlife, domestic animals, and humans is of great concern to conservation issues and public health. Here we report on the prevalence of anti-Leishmania sp. antibodies in 21 wild canids (7 Chrysocyon brachyurus, 12 Cerdocyon thous, and 2 Lycalopex vetulus) and 74 free domestic dogs (Canis familiaris) sampled around the Serra do Cipó National Park. In dogs, the apparent prevalence was 8.1% and in wild canids it was 19% (2 crab-eating foxes, C. thous, and 2 maned wolves, C. brachyurus). Management of the domestic dog population with evaluation of incidence changes in humans and wildlife, and enlightenment on the role of wild reservoirs are essential issues for future action and research.

  15. Serologic evidence of Leishmania infection in free-ranging wild and domestic canids around a Brazilian National Park

    Directory of Open Access Journals (Sweden)

    Nelson Henrique de Almeida Curi

    2006-02-01

    Full Text Available Transmission of disease between wildlife, domestic animals, and humans is of great concern to conservation issues and public health. Here we report on the prevalence of anti-Leishmania sp. antibodies in 21 wild canids (7 Chrysocyon brachyurus, 12 Cerdocyon thous, and 2 Lycalopex vetulus and 74 free domestic dogs (Canis familiaris sampled around the Serra do Cipó National Park. In dogs, the apparent prevalence was 8.1% and in wild canids it was 19% (2 crab-eating foxes, C. thous, and 2 maned wolves, C. brachyurus. Management of the domestic dog population with evaluation of incidence changes in humans and wildlife, and enlightenment on the role of wild reservoirs are essential issues for future action and research.

  16. Natural Infection of Wild Canids (Cerdocyon thous and Lycalopex gymnocercus) with the Intraendothelial Piroplasm Rangelia vitalii in Southern Brazil.

    Science.gov (United States)

    Fredo, Gabriela; Bianchi, Matheus V; De Andrade, Caroline P; De Souza, Suyene O; Leite-Filho, Ronaldo V; Bandinelli, Marcele B; Amorim, Derek B; Driemeier, David; Sonne, Luciana

    2015-10-01

    Rangelia vitalii is a piroplasm that infects canines, causing lesions typical of a hemolytic disorder. Two wild canids, a crab-eating fox (Cerdocyon thous) and a Pampas fox (Lycalopex gymnocercus), were presented for necropsy in Setor de Patologia Veterinária at the Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. On gross examination, both animals had pale mucosae and moderate tick infestation (Amblyomma aureolatum). There was severe splenomegaly, and the liver had a diffusely orange-reddish lobular pattern. The mesenteric lymph nodes were brownish and slightly enlarged. Structures compatible with R. vitalii were observed in the cytoplasm of endothelial cells in the liver, stomach, heart, kidney, lungs, lymph nodes, and bladder. The agent was characterized by PCR and genetic sequencing of liver samples and ticks. We show that parasitism with R. vitalii follows an epidemiologic cycle in which wild canids act as reservoirs.

  17. THE STAR FORMATION HISTORY OF BCGs TO z = 1.8 FROM THE SpARCS/SWIRE SURVEY: EVIDENCE FOR SIGNIFICANT IN SITU STAR FORMATION AT HIGH REDSHIFT

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Tracy M. A.; Bonaventura, Nina [McGill University, 3600 rue University, Montreal, QC H3A 2T8 (Canada); Muzzin, Adam [Leiden Observatory, University of Leiden, P.O. Box 9514, 2300 RA Leiden (Netherlands); Noble, Allison; Yee, H. K. C. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Geach, James [Centre for Astrophysics Research, University of Hertfordshire, Hatfield, Hertfordshire AL109AB (United Kingdom); Hezevah, Yashar [Kavli Institue for Particle Physics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305-4085 (United States); Lidman, Chris [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Wilson, Gillian [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Surace, Jason [Spitzer Science Center, California Institute of Technology, M/S 314-6, Pasadena, CA 91125 (United States); Shupe, David [NASA Herschel Science Center, IPAC, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)

    2015-12-01

    We present the results of an MIPS-24 μm study of the brightest cluster galaxies (BCGs) of 535 high-redshift galaxy clusters. The clusters are drawn from the Spitzer Adaptation of the Red-Sequence Cluster Survey, which effectively provides a sample selected on total stellar mass, over 0.2 < z < 1.8 within the Spitzer Wide-Area Infrared Extragalactic (SWIRE) Survey fields. Twenty percent, or 106 clusters, have spectroscopically confirmed redshifts, and the rest have redshifts estimated from the color of their red sequence. A comparison with the public SWIRE images detects 125 individual BCGs at 24 μm ≳ 100 μJy, or 23%. The luminosity-limited detection rate of BCGs in similar richness clusters (N{sub gal} > 12) increases rapidly with redshift. Above z ∼ 1, an average of ∼20% of the sample have 24 μm inferred infrared luminosities of L{sub IR} > 10{sup 12} L{sub ⊙}, while the fraction below z ∼ 1 exhibiting such luminosities is <1%. The Spitzer-IRAC colors indicate the bulk of the 24 μm detected population is predominantly powered by star formation, with only 7/125 galaxies lying within the color region inhabited by active galactic nuclei (AGNs). Simple arguments limit the star formation activity to several hundred million years and this may therefore be indicative of the timescale for AGN feedback to halt the star formation. Below redshift z ∼ 1, there is not enough star formation to significantly contribute to the overall stellar mass of the BCG population, and therefore BCG growth is likely dominated by dry mergers. Above z ∼ 1, however, the inferred star formation would double the stellar mass of the BCGs and is comparable to the mass assembly predicted by simulations through dry mergers. We cannot yet constrain the process driving the star formation for the overall sample, though a single object studied in detail is consistent with a gas-rich merger.

  18. Planck intermediate results. XXVII. High-redshift infrared galaxy overdensity candidates and lensed sources discovered by Planck and confirmed by Herschel-SPIRE

    Science.gov (United States)

    Planck Collaboration; Aghanim, N.; Altieri, B.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Battaner, E.; Beelen, A.; Benabed, K.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bethermin, M.; Bielewicz, P.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Burigana, C.; Calabrese, E.; Canameras, R.; Cardoso, J.-F.; Catalano, A.; Chamballu, A.; Chary, R.-R.; Chiang, H. C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Couchot, F.; Crill, B. P.; Curto, A.; Danese, L.; Dassas, K.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Falgarone, E.; Flores-Cacho, I.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Frye, B.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Guéry, D.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Helou, G.; Hernández-Monteagudo, C.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Le Floc'h, E.; Leonardi, R.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; MacKenzie, T.; Maffei, B.; Mandolesi, N.; Maris, M.; Martin, P. G.; Martinache, C.; Martínez-González, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; Melchiorri, A.; Mennella, A.; Migliaccio, M.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Natoli, P.; Negrello, M.; Nesvadba, N. P. H.; Novikov, D.; Novikov, I.; Omont, A.; Pagano, L.; Pajot, F.; Pasian, F.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Popa, L.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ristorcelli, I.; Rocha, G.; Roudier, G.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Spencer, L. D.; Stolyarov, V.; Sunyaev, R.; Sutton, D.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Valtchanov, I.; Van Tent, B.; Vieira, J. D.; Vielva, P.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Welikala, N.; Zacchei, A.; Zonca, A.

    2015-10-01

    We have used the Planck all-sky submillimetre and millimetre maps to search for rare sources distinguished by extreme brightness, a few hundred millijanskies, and their potential for being situated at high redshift. These "cold" Planck sources, selected using the High Frequency Instrument (HFI) directly from the maps and from the Planck Catalogue of Compact Sources (PCCS), all satisfy the criterion of having their rest-frame far-infrared peak redshifted to the frequency range 353-857 GHz. This colour-selection favours galaxies in the redshift range z = 2-4, which we consider as cold peaks in the cosmic infrared background. With a 4.´5 beam at the four highest frequencies, our sample is expected to include overdensities of galaxies in groups or clusters, lensed galaxies, and chance line-of-sight projections. We perform a dedicated Herschel-SPIRE follow-up of 234 such Planck targets, finding a significant excess of red 350 and 500μm sources, in comparison to reference SPIRE fields. About 94% of the SPIRE sources in the Planck fields are consistent with being overdensities of galaxies peaking at 350μm, with 3% peaking at 500μm, and none peaking at 250μm. About 3% are candidate lensed systems, all 12 of which have secure spectroscopic confirmations, placing them at redshifts z> 2.2. Only four targets are Galactic cirrus, yielding a success rate in our search strategy for identifying extragalactic sources within the Planck beam of better than 98%. The galaxy overdensities are detected with high significance, half of the sample showing statistical significance above 10σ. The SPIRE photometric redshifts of galaxies in overdensities suggest a peak at z ≃ 2, assuming a single common dust temperature for the sources of Td = 35 K. Under this assumption, we derive an infrared (IR) luminosity for each SPIRE source of about 4 × 1012L⊙, yielding star formation rates of typically 700 M⊙ yr-1. If the observed overdensities are actual gravitationally-bound structures

  19. An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS). IV. Discovery of High-redshift AGB Analogs

    Science.gov (United States)

    Boyer, M. L.; McQuinn, K. B. W.; Groenewegen, M. A. T.; Zijlstra, A. A.; Whitelock, P. A.; van Loon, J. Th.; Sonneborn, G.; Sloan, G. C.; Skillman, E. D.; Meixner, M.; McDonald, I.; Jones, O. C.; Javadi, A.; Gehrz, R. D.; Britavskiy, N.; Bonanos, A. Z.

    2017-12-01

    The survey for DUST in Nearby Galaxies with Spitzer (DUSTiNGS) identified several candidate Asymptotic Giant Branch (AGB) stars in nearby dwarf galaxies and showed that dust can form even in very metal-poor systems ({\\boldsymbol{Z}}∼ 0.008 {Z}ȯ ). Here, we present a follow-up survey with WFC3/IR on the Hubble Space Telescope (HST), using filters that are capable of distinguishing carbon-rich (C-type) stars from oxygen-rich (M-type) stars: F127M, F139M, and F153M. We include six star-forming DUSTiNGS galaxies (NGC 147, IC 10, Pegasus dIrr, Sextans B, Sextans A, and Sag DIG), all more metal-poor than the Magellanic Clouds and spanning 1 dex in metallicity. We double the number of dusty AGB stars known in these galaxies and find that most are carbon rich. We also find 26 dusty M-type stars, mostly in IC 10. Given the large dust excess and tight spatial distribution of these M-type stars, they are most likely on the upper end of the AGB mass range (stars undergoing Hot Bottom Burning). Theoretical models do not predict significant dust production in metal-poor M-type stars, but we see evidence for dust excess around M-type stars even in the most metal-poor galaxies in our sample (12+{log}({{O}}/{{H}})=7.26{--}7.50). The low metallicities and inferred high stellar masses (up to ∼10 {M}ȯ ) suggest that AGB stars can produce dust very early in the evolution of galaxies (∼30 Myr after they form), and may contribute significantly to the dust reservoirs seen in high-redshift galaxies. Based on observations made with the NASA/ESA Hubble Space Telescope 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 GO-14073.

  20. Quantity discrimination in canids: Dogs (Canis familiaris) and wolves (Canis lupus) compared.

    Science.gov (United States)

    Miletto Petrazzini, Maria Elena; Wynne, Clive D L

    2017-11-01

    Accumulating evidence indicates that animals are able to discriminate between quantities. Recent studies have shown that dogs' and coyotes' ability to discriminate between quantities of food items decreases with increasing numerical ratio. Conversely, wolves' performance is not affected by numerical ratio. Cross-species comparisons are difficult because of differences in the methodologies employed, and hence it is still unclear whether domestication altered quantitative abilities in canids. Here we used the same procedure to compare pet dogs and wolves in a spontaneous food choice task. Subjects were presented with two quantities of food items and allowed to choose only one option. Four numerical contrasts of increasing difficulty (range 1-4) were used to assess the influence of numerical ratio on the performance of the two species. Dogs' accuracy was affected by numerical ratio, while no ratio effect was observed in wolves. These results align with previous findings and reinforce the idea of different quantitative competences in dogs and wolves. Although we cannot exclude that other variables might have played a role in shaping quantitative abilities in these two species, our results might suggest that the interspecific differences here reported may have arisen as a result of domestication. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Complete Mitochondrial Genome of the Red Fox (Vuples vuples) and Phylogenetic Analysis with Other Canid Species.

    Science.gov (United States)

    Zhong, Hua-Ming; Zhang, Hong-Hai; Sha, Wei-Lai; Zhang, Cheng-De; Chen, Yu-Cai

    2010-04-01

    The whole mitochondrial genome sequence of red fox (Vuples vuples) was determined. It had a total length of 16 723 bp. As in most mammal mitochondrial genome, it contained 13 protein coding genes, two ribosome RNA genes, 22 transfer RNA genes and one control region. The base composition was 31.3% A, 26.1% C, 14.8% G and 27.8% T, respectively. The codon usage of red fox, arctic fox, gray wolf, domestic dog and coyote followed the same pattern except for an unusual ATT start codon, which initiates the NADH dehydrogenase subunit 3 gene in the red fox. A long tandem repeat rich in AC was found between conserved sequence block 1 and 2 in the control region. In order to confirm the phylogenetic relationships of red fox to other canids, phylogenetic trees were reconstructed by neighbor-joining and maximum parsimony methods using 12 concatenated heavy-strand protein-coding genes. The result indicated that arctic fox was the sister group of red fox and they both belong to the red fox-like clade in family Canidae, while gray wolf, domestic dog and coyote belong to wolf-like clade. The result was in accordance with existing phylogenetic results.

  2. Evidence of coat color variation sheds new light on ancient canids.

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    Morgane Ollivier

    Full Text Available We have used a paleogenetics approach to investigate the genetic landscape of coat color variation in ancient Eurasian dog and wolf populations. We amplified DNA fragments of two genes controlling coat color, Mc1r (Melanocortin 1 Receptor and CBD103 (canine-β-defensin, in respectively 15 and 19 ancient canids (dogs and wolf morphotypes from 14 different archeological sites, throughout Asia and Europe spanning from ca. 12 000 B.P. (end of Upper Palaeolithic to ca. 4000 B.P. (Bronze Age. We provide evidence of a new variant (R301C of the Melanocortin 1 receptor (Mc1r and highlight the presence of the beta-defensin melanistic mutation (CDB103-K locus on ancient DNA from dog-and wolf-morphotype specimens. We show that the dominant K(B allele (CBD103, which causes melanism, and R301C (Mc1r, the variant that may cause light hair color, are present as early as the beginning of the Holocene, over 10,000 years ago. These results underline the genetic diversity of prehistoric dogs. This diversity may have partly stemmed not only from the wolf gene pool captured by domestication but also from mutations very likely linked to the relaxation of natural selection pressure occurring in-line with this process.

  3. Outbreaks of canid herpesvirus 1 disease in puppies in southern Brazil

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    Juliana F. Cargnelutti

    2015-06-01

    Full Text Available Abstract: Canid herpesvirus 1 (CHV-1 is a widespread pathogen of dogs and produces infertility, abortions and severe systemic disease in young puppies. Clinical data indicate the circulation of CHV-1 among Brazilian dogs yet definitive diagnosis has rarely been accomplished. This article describes the clinicopathological findings of four independent cases/outbreaks of neonatal disease by CHV-1 in Bulldog puppies followed by virus identification and genetic characterization. Three events occurred in a kennel holding dogs of different breeds at reproductive age (March 2013, October 2013 and April 2014. Puppies from three French or English Bulldog litters, aging 9 to 30 days were affected, presenting dyspnea, agonic breathing, pale mucous, abdominal pain and tension, evolving to death within about 24 hours. At necropsy, the puppies presented necrohemorrhagic hepatitis, multifocal and moderate necrohemorrhagic nephritis and fibrinonecrotic interstitial pneumonia. Virus isolation was positive in clinical specimens from one litter and CHV-1 DNA was detected by PCR in tissues from all four cases. Virus-neutralizing assays with samples of the affected kennel revealed 9/12 adult animals with high antibody titers to CHV-1. Nucleotide sequencing of glycoprotein B, C and D genes revealed 99-100% of identity among the viruses and with CHV-1 sequences available in GenBank. Phylogenetic analyses of gC sequences showed a segregation of the samples, even among three isolates from the same kennel. These findings support CHV-1 infection as the cause of disease and death in these dog litters, reinforcing the need for correct etiologic diagnosis, prevention and immunization against CHV-1 in dogs from Southern Brazil.

  4. Major histocompatibility complex (MHC) variation in the endangered Mexican wolf and related canids.

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    Hedrick, P W; Lee, R N; Parker, K M

    2000-12-01

    We have examined in Mexican wolves and related canids the amount of genetic variation for a class II gene in the major histocompatibility complex (MHC), thought to be part of the most important genetic basis for pathogen resistance in vertebrates. In Mexican wolves, descended from only seven founders over three lineages, there were five different alleles. These were in three phylogenetic groups, only one of which was shared between lineages. Using single stand conformation polymorphism (SSCP), we found that in samples of animals from the two polymorphic lineages, the observed heterozygosity was 0.74 and the genotypes were not different statistically from Hardy-Weinberg proportions. The Ghost Ranch lineage of Mexican wolves was monomorphic for the locus, consistent with the lower level of variation found previously for microsatellite loci and predicted from pedigree analysis. Samples of grey wolves, red wolves, and coyotes had 16 additional alleles. One Mexican wolf allele was also found in grey wolves and another allele was shared between grey and red wolves. Most of the nucleotide variation resulted in amino acid variation and there were five different amino acids found at two different positions. Only two of the 21 variable amino acid positions had solely synonymous nucleotide variation. The average heterozygosity for eight individual amino acid positions in the Mexican wolves was greater than 0.4. The estimated rate of nonsynonymous substitution was 2.5 times higher than that for synonymous substitution for the putative antigen binding site positions, indicative of positive selection acting on these positions. Examination of the known dog sequences for this locus showed that one of the Mexican wolf alleles was found in dogs and that the allele found in both grey and red wolves is also found in dogs.

  5. Meerkats (Suricata suricatta), a new definitive host of the canid nematodeAngiostrongylus vasorum.

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    Gillis-Germitsch, Nina; Manser, Marta B; Hilbe, Monika; Schnyder, Manuela

    2017-12-01

    Angiostronglyus vasorum is a cardiopulmonary nematode infecting mainly canids such as dogs ( Canis familiaris ) and foxes ( Vulpes vulpes ). Natural infections have also been reported in mustelids and red pandas ( Ailurus fulgens fulgens ). We report the occurrence of natural A. vasorum infections in a group of captive meerkats ( Suricata suricatta ), housed at a university facility in Switzerland. A. vasorum first-stage larvae (L1) were initially identified in a pooled faecal sample. Individual samples, investigated with the Baermann-Wetzel technique, revealed that 41% (7/17) of the meerkats were infected, with ranges of 2-125 L1/g faeces. PCR and sequencing of part of the ITS-2 region resulted in 100% identity with A. vasorum . Infected animals did not show clinical signs. One meerkat died two days after diagnosis. Upon necropsy one adult specimen was recovered; histological examination of the lung revealed granulomatous pneumonia caused by A. vasorum larvae and eggs as well as intima and media hyperplasia and isolated arteriosclerosis of larger lung vessels. However, the cause of death was a spleen rupture with associated blood loss. All meerkats were topically treated with 10 mg imidacloprid/2.5 mg moxidectin per animal, after which they became negative in all follow up faecal examinations. Potential intermediate (gastropods) and paratenic hosts (birds) were collected from within or outside the meerkats enclosure. Gastropods were examined by PCR and bird samples by digestion. Four out of 193 (2.1%) gastropod samples were positive for A. vasorum , whereas none of the bird samples were positive. Meerkats, belonging to the Herpestidae, therefore are suitable definitive hosts for A. vasorum, with production and excretion of live L1. Meerkats kept in captivity in areas where A. vasorum is endemic and with potential contact to intermediate hosts are at risk of infection. Regular faecal examinations including Baermann-Wetzel technique should be considered.

  6. A thyroid peroxidase (TPO) mutation in dogs reveals a canid-specific gene structure.

    Science.gov (United States)

    Fyfe, John C; Lynch, Mary; Olsen, Jayme; Louёr, Eric

    2013-04-01

    Congenital hypothyroidism with goiter (CHG) occurring as an autosomal recessive disorder is typically due to a defect of thyroid hormone synthesis (aka dyshormonogenesis). Thyroid peroxidase (TPO) is a multifunctional, heme-containing enzyme whose activity is required, and several inactivating TPO mutations causing CHG in humans and dogs have been described. Recently, two half-sib Spanish water dog (SWD) pups were diagnosed with CHG based on clinical signs, endocrine testing, and thyroid histology. TPO enzyme activity was absent, and immuno-cross-reactive TPO was undetectable in affected-dog thyroid tissue. A single guanosine insertion was observed in the first exon of the affected-dog TPO cDNA at a site not previously thought to be within the coding sequence. The insertion allele segregated with the deduced disease allele in the SWD breed and was not observed in unrelated dogs of various breeds. Comparison of the insertion site (an 8-nt poly-G tract) with the orthologous sequences of other mammalian reference genomes revealed that the octa-G tract obliterated the intron 1 splice acceptor site and the exon 2 translation initiation codon found at that position in other species. An in-frame ATG in strong Kozak consensus context was observed in the normal dog sequence 12 codons 5' of the usual mammalian start site, suggesting that dogs have lost the noncoding exon 1 demonstrated in human and mouse. A survey of TPO sequences in other carnivore species indicates that the poly-G tract necessitating an alternative translation initiation site is a canid-specific feature.

  7. Latest Early Pleistocene wolf-like canids from the Iberian Peninsula

    Science.gov (United States)

    Bartolini Lucenti, Saverio; Alba, David M.; Rook, Lorenzo; Moyà-Solà, Salvador; Madurell-Malapeira, Joan

    2017-04-01

    Several species of the genus Canis (Carnivora: Canidae) have been recorded from the European Early Pleistocene, but the phylogenetic relationships among them and in relation to extant members of this genus are still unclear. This is particularly true for the medium-sized and wolf-like extinct species Canis mosbachensis. It has been considered by many researchers as a descendant of the larger Canis etruscus and as a likely putative ancestor of extant wolves (Canis lupus). Other scholars, in contrast, have advocated instead for a closer relationship between C. mosbachensis and the extinct Canis arnensis, and even a close relationship between C. mosbachensis and C. lupus has been questioned. Here we describe the previously unpublished medium-sized Canis remains from the late Early Pleistocene site of Vallparadís Estació, along with additional new Canis material from the roughly coeval site of Cueva Victoria (both in the Iberian Peninsula), and compare them qualitatively and morphometrically with both extant and extinct species of this genus. The described material most closely resembles in craniodental size and shape the remains from Central and Southern Europe that have been previously assigned to C. mosbachensis, to which they are hence formally attributed. The excellent preservation of the newly described specimens (which include the most complete skull of this taxon) enables the description of features previously unknown for this species, which further support a close phylogenetic link with living wolves. Based on the described material, we review the role played by C. mosbachensis in the evolutionary history of European fossil canids, and conclude that this extinct species is most closely related to C. lupus and other closely-allied species, such as Canis anthus and Canis latrans.

  8. Factors associated with uterine endometrial hyperplasia and pyometra in wild canids: implications for fertility.

    Science.gov (United States)

    Asa, Cheryl S; Bauman, Karen L; Devery, Sarah; Zordan, Martín; Camilo, Gerardo R; Boutelle, Sally; Moresco, Anneke

    2014-01-01

    The ability to safely and effectively manage reproduction is central to the success of AZA captive-breeding programs. Although the AZA Wildlife Contraception Center routinely monitors contraceptive safety, there have been no studies that compare the effects of contraceptive use to separation of males from females, the other option for preventing reproduction. We used retrospective medical records and pathology reports submitted by AZA and related facilities for the seven AZA-managed canid species to assess rates of uterine pathology relative to female reproductive life histories. Our results showed that the prevalence of both pyometra and endometrial hyperplasia (EH) was associated not only with treatment with the two most common contraceptives (Suprelorin® and MGA implants) but also with the number of years barren (i.e., not producing a litter and not contracepted). Rates of pyometra and EH were especially high in African painted dogs and red wolves, but lowest in swift and fennec foxes. The number of years producing a litter had a low association, suggesting it could be protective against uterine pathology. A more recently developed Suprelorin® protocol using Ovaban® to prevent the initial stimulation phase, followed by implant removal when reversal is desired, may be a safer contraceptive option. These results concerning the relationship between reproductive management and uterine health have important implications for AZA-managed programs, since the unsustainability of many captive populations may be due at least in part to infertility. Managing a female's reproductive lifespan to optimize or maintain fertility will require a reconsideration of how breeding recommendations are formulated. © 2013 Wiley Periodicals, Inc.

  9. Prevalence of canid herpesvirus-1 infection in stillborn and dead neonatal puppies in Denmark.

    Science.gov (United States)

    Larsen, Rikke W; Kiupel, Matti; Balzer, Hans-Jörg; Agerholm, Jørgen S

    2015-01-08

    Canid herpesvirus-1 (CaHV-1) infection in puppies less than three weeks of age is often reported to be associated with a lethal generalized necrotizing inflammation and since the discovery of the virus in 1965 several reports of neonatal infections have been published. However, the significance of CaHV-1 for peri- and neonatal mortality in puppies remains unclear. Therefore, we examined stillborn and dead neonatal puppies in Denmark to determine the prevalence of infection and further to correlate infection levels with necropsy findings to assess the possible significance of the infection. From a cross-sectional study of 57 dead puppies, 22.8% (n = 13) were confirmed positive for CaHV-1 by real-time polymerase chain reaction (PCR) of tissue pools of lung/liver and/or spleen/kidney. Specimens from PCR positive cases were further investigated by histology and in situ hybridization (ISH). High levels of CaHV-1 DNA were present in only one case in which lesions and ISH staining consistent with CaHV-1 infection were found as well. CaHV-1 concentrations in the other cases were low and a range of lesions not consistent with CaHV-1 were found. Similar, ISH staining was mostly negative in these except for one case with a few positive cells. CaHV-1 infection in stillborn and dead neonatal puppies in Denmark seems to be common, but the direct significance for puppy mortality remains unclear as only one of 13 PCR positive puppies (7.7%) had pathognomonic lesions.

  10. An evaluation of the PCR-RFLP technique to aid molecular-based monitoring of felids and canids in India

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    Home Chandrima

    2010-06-01

    Full Text Available Abstract Background The order Carnivora is well represented in India, with 58 of the 250 species found globally, occurring here. However, small carnivores figure very poorly in research and conservation policies in India. This is mainly due to the dearth of tested and standardized techniques that are both cost effective and conducive to small carnivore studies in the field. In this paper we present a non-invasive genetic technique standardized for the study of Indian felids and canids with the use of PCR amplification and restriction enzyme digestion of scat collected in the field. Findings Using existing sequences of felids and canids from GenBank, we designed primers from the 16S rRNA region of the mitochondrial genome and tested these on ten species of felids and five canids. We selected restriction enzymes that would cut the selected region differentially for various species within each family. We produced a restriction digestion profile for the potential differentiation of species based on fragment patterns. To test our technique, we used felid PCR primers on scats collected from various habitats in India, representing varied environmental conditions. Amplification success with field collected scats was 52%, while 86% of the products used for restriction digestion could be accurately assigned to species. We verified this through sequencing. A comparison of costs across the various techniques currently used for scat assignment showed that this technique was the most practical and cost effective. Conclusions The species-specific key developed in this paper provides a means for detailed investigations in the future that focus on elusive carnivores in India and this approach provides a model for other studies in areas of Asia where many small carnivores co-occur.

  11. A comparison of facial color pattern and gazing behavior in canid species suggests gaze communication in gray wolves (Canis lupus.

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    Sayoko Ueda

    Full Text Available As facial color pattern around the eyes has been suggested to serve various adaptive functions related to the gaze signal, we compared the patterns among 25 canid species, focusing on the gaze signal, to estimate the function of facial color pattern in these species. The facial color patterns of the studied species could be categorized into the following three types based on contrast indices relating to the gaze signal: A-type (both pupil position in the eye outline and eye position in the face are clear, B-type (only the eye position is clear, and C-type (both the pupil and eye position are unclear. A-type faces with light-colored irises were observed in most studied species of the wolf-like clade and some of the red fox-like clade. A-type faces tended to be observed in species living in family groups all year-round, whereas B-type faces tended to be seen in solo/pair-living species. The duration of gazing behavior during which the facial gaze-signal is displayed to the other individual was longest in gray wolves with typical A-type faces, of intermediate length in fennec foxes with typical B-type faces, and shortest in bush dogs with typical C-type faces. These results suggest that the facial color pattern of canid species is related to their gaze communication and that canids with A-type faces, especially gray wolves, use the gaze signal in conspecific communication.

  12. A comparison of facial color pattern and gazing behavior in canid species suggests gaze communication in gray wolves (Canis lupus).

    Science.gov (United States)

    Ueda, Sayoko; Kumagai, Gaku; Otaki, Yusuke; Yamaguchi, Shinya; Kohshima, Shiro

    2014-01-01

    As facial color pattern around the eyes has been suggested to serve various adaptive functions related to the gaze signal, we compared the patterns among 25 canid species, focusing on the gaze signal, to estimate the function of facial color pattern in these species. The facial color patterns of the studied species could be categorized into the following three types based on contrast indices relating to the gaze signal: A-type (both pupil position in the eye outline and eye position in the face are clear), B-type (only the eye position is clear), and C-type (both the pupil and eye position are unclear). A-type faces with light-colored irises were observed in most studied species of the wolf-like clade and some of the red fox-like clade. A-type faces tended to be observed in species living in family groups all year-round, whereas B-type faces tended to be seen in solo/pair-living species. The duration of gazing behavior during which the facial gaze-signal is displayed to the other individual was longest in gray wolves with typical A-type faces, of intermediate length in fennec foxes with typical B-type faces, and shortest in bush dogs with typical C-type faces. These results suggest that the facial color pattern of canid species is related to their gaze communication and that canids with A-type faces, especially gray wolves, use the gaze signal in conspecific communication.

  13. Water developments and canids in two North American deserts: a test of the indirect effect of water hypothesis.

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    Lucas K Hall

    Full Text Available Anthropogenic modifications to landscapes intended to benefit wildlife may negatively influence wildlife communities. Anthropogenic provisioning of free water (water developments to enhance abundance and distribution of wildlife is a common management practice in arid regions where water is limiting. Despite the long-term and widespread use of water developments, little is known about how they influence native species. Water developments may negatively influence arid-adapted species (e.g., kit fox, Vulpes macrotis by enabling water-dependent competitors (e.g., coyote, Canis latrans to expand distribution in arid landscapes (i.e., indirect effect of water hypothesis. We tested the two predictions of the indirect effect of water hypothesis (i.e., coyotes will visit areas with free water more frequently and kit foxes will spatially and temporally avoid coyotes and evaluated relative use of free water by canids in the Great Basin and Mojave Deserts from 2010 to 2012. We established scent stations in areas with (wet and without (dry free water and monitored visitation by canids to these sites and visitation to water sources using infrared-triggered cameras. There was no difference in the proportions of visits to scent stations in wet or dry areas by coyotes or kit foxes at either study area. We did not detect spatial (no negative correlation between visits to scent stations or temporal (no difference between times when stations were visited segregation between coyotes and kit foxes. Visitation to water sources was not different for coyotes between study areas, but kit foxes visited water sources more in Mojave than Great Basin. Our results did not support the indirect effect of water hypothesis in the Great Basin or Mojave Deserts for these two canids.

  14. Water Developments and Canids in Two North American Deserts: A Test of the Indirect Effect of Water Hypothesis

    Science.gov (United States)

    Hall, Lucas K.; Larsen, Randy T.; Knight, Robert N.; Bunnell, Kevin D.; McMillan, Brock R.

    2013-01-01

    Anthropogenic modifications to landscapes intended to benefit wildlife may negatively influence wildlife communities. Anthropogenic provisioning of free water (water developments) to enhance abundance and distribution of wildlife is a common management practice in arid regions where water is limiting. Despite the long-term and widespread use of water developments, little is known about how they influence native species. Water developments may negatively influence arid-adapted species (e.g., kit fox, Vulpes macrotis) by enabling water-dependent competitors (e.g., coyote, Canis latrans) to expand distribution in arid landscapes (i.e., indirect effect of water hypothesis). We tested the two predictions of the indirect effect of water hypothesis (i.e., coyotes will visit areas with free water more frequently and kit foxes will spatially and temporally avoid coyotes) and evaluated relative use of free water by canids in the Great Basin and Mojave Deserts from 2010 to 2012. We established scent stations in areas with (wet) and without (dry) free water and monitored visitation by canids to these sites and visitation to water sources using infrared-triggered cameras. There was no difference in the proportions of visits to scent stations in wet or dry areas by coyotes or kit foxes at either study area. We did not detect spatial (no negative correlation between visits to scent stations) or temporal (no difference between times when stations were visited) segregation between coyotes and kit foxes. Visitation to water sources was not different for coyotes between study areas, but kit foxes visited water sources more in Mojave than Great Basin. Our results did not support the indirect effect of water hypothesis in the Great Basin or Mojave Deserts for these two canids. PMID:23844097

  15. Meerkats (Suricata suricatta, a new definitive host of the canid nematode Angiostrongylus vasorum

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    Nina Gillis-Germitsch

    2017-12-01

    Full Text Available Angiostronglyus vasorum is a cardiopulmonary nematode infecting mainly canids such as dogs (Canis familiaris and foxes (Vulpes vulpes. Natural infections have also been reported in mustelids and red pandas (Ailurus fulgens fulgens. We report the occurrence of natural A. vasorum infections in a group of captive meerkats (Suricata suricatta, housed at a university facility in Switzerland. A. vasorum first-stage larvae (L1 were initially identified in a pooled faecal sample. Individual samples, investigated with the Baermann-Wetzel technique, revealed that 41% (7/17 of the meerkats were infected, with ranges of 2–125 L1/g faeces. PCR and sequencing of part of the ITS-2 region resulted in 100% identity with A. vasorum. Infected animals did not show clinical signs. One meerkat died two days after diagnosis. Upon necropsy one adult specimen was recovered; histological examination of the lung revealed granulomatous pneumonia caused by A. vasorum larvae and eggs as well as intima and media hyperplasia and isolated arteriosclerosis of larger lung vessels. However, the cause of death was a spleen rupture with associated blood loss. All meerkats were topically treated with 10 mg imidacloprid/2.5 mg moxidectin per animal, after which they became negative in all follow up faecal examinations. Potential intermediate (gastropods and paratenic hosts (birds were collected from within or outside the meerkats enclosure. Gastropods were examined by PCR and bird samples by digestion. Four out of 193 (2.1% gastropod samples were positive for A. vasorum, whereas none of the bird samples were positive. Meerkats, belonging to the Herpestidae, therefore are suitable definitive hosts for A. vasorum, with production and excretion of live L1. Meerkats kept in captivity in areas where A. vasorum is endemic and with potential contact to intermediate hosts are at risk of infection. Regular faecal examinations including Baermann-Wetzel technique should be considered

  16. A serological survey of infectious disease in Yellowstone National Park's canid community.

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    Emily S Almberg

    Full Text Available BACKGROUND: Gray wolves (Canis lupus were reintroduced into Yellowstone National Park (YNP after a >70 year absence, and as part of recovery efforts, the population has been closely monitored. In 1999 and 2005, pup survival was significantly reduced, suggestive of disease outbreaks. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed sympatric wolf, coyote (Canis latrans, and red fox (Vulpes vulpes serologic data from YNP, spanning 1991-2007, to identify long-term patterns of pathogen exposure, identify associated risk factors, and examine evidence for disease-induced mortality among wolves for which there were survival data. We found high, constant exposure to canine parvovirus (wolf seroprevalence: 100%; coyote: 94%, canine adenovirus-1 (wolf pups [0.5-0.9 yr]: 91%, adults [>or=1 yr]: 96%; coyote juveniles [0.5-1.5 yrs]: 18%, adults [>or=1.6 yrs]: 83%, and canine herpesvirus (wolf: 87%; coyote juveniles: 23%, young adults [1.6-4.9 yrs]: 51%, old adults [>or=5 yrs]: 87% suggesting that these pathogens were enzootic within YNP wolves and coyotes. An average of 50% of wolves exhibited exposure to the protozoan parasite, Neospora caninum, although individuals' odds of exposure tended to increase with age and was temporally variable. Wolf, coyote, and fox exposure to canine distemper virus (CDV was temporally variable, with evidence for distinct multi-host outbreaks in 1999 and 2005, and perhaps a smaller, isolated outbreak among wolves in the interior of YNP in 2002. The years of high wolf-pup mortality in 1999 and 2005 in the northern region of the park were correlated with peaks in CDV seroprevalence, suggesting that CDV contributed to the observed mortality. CONCLUSIONS/SIGNIFICANCE: Of the pathogens we examined, none appear to jeopardize the long-term population of canids in YNP. However, CDV appears capable of causing short-term population declines. Additional information on how and where CDV is maintained and the frequency with which future

  17. A serological survey of infectious disease in Yellowstone National Park's canid community

    Science.gov (United States)

    Almberg, E.S.; Mech, L.D.; Smith, D.W.; Sheldon, J.W.; Crabtree, R.L.

    2009-01-01

    Background: Gray wolves (Canis lupus) were reintroduced into Yellowstone National Park (YNP) after a >70 year absence, and as part of recovery efforts, the population has been closely monitored. In 1999 and 2005, pup survival was significantly reduced, suggestive of disease outbreaks. Methodology/Principal Findings: We analyzed sympatric wolf, coyote (Canis latrans), and red fox (Vulpes vulpes) serologic data from YNP, spanning 1991–2007, to identify long-term patterns of pathogen exposure, identify associated risk factors, and examine evidence for disease-induced mortality among wolves for which there were survival data. We found high, constant exposure to canine parvovirus (wolf seroprevalence: 100%; coyote: 94%), canine adenovirus-1 (wolf pups [0.5–0.9 yr]: 91%, adults [≥1 yr]: 96%; coyote juveniles [0.5–1.5 yrs]: 18%, adults [≥1.6 yrs]: 83%), and canine herpesvirus (wolf: 87%; coyote juveniles: 23%, young adults [1.6–4.9 yrs]: 51%, old adults [≥5 yrs]: 87%) suggesting that these pathogens were enzootic within YNP wolves and coyotes. An average of 50% of wolves exhibited exposure to the protozoan parasite, Neospora caninum, although individuals’ odds of exposure tended to increase with age and was temporally variable. Wolf, coyote, and fox exposure to canine distemper virus (CDV) was temporally variable, with evidence for distinct multi-host outbreaks in 1999 and 2005, and perhaps a smaller, isolated outbreak among wolves in the interior of YNP in 2002. The years of high wolf-pup mortality in 1999 and 2005 in the northern region of the park were correlated with peaks in CDV seroprevalence, suggesting that CDV contributed to the observed mortality. Conclusions/Significance: Of the pathogens we examined, none appear to jeopardize the long-term population of canids in YNP. However, CDV appears capable of causing short-term population declines. Additional information on how and where CDV is maintained and the frequency with which future epizootics

  18. A Serological Survey of Infectious Disease in Yellowstone National Park’s Canid Community

    Science.gov (United States)

    Almberg, Emily S.; Mech, L. David; Smith, Douglas W.; Sheldon, Jennifer W.; Crabtree, Robert L.

    2009-01-01

    Background Gray wolves (Canis lupus) were reintroduced into Yellowstone National Park (YNP) after a >70 year absence, and as part of recovery efforts, the population has been closely monitored. In 1999 and 2005, pup survival was significantly reduced, suggestive of disease outbreaks. Methodology/Principal Findings We analyzed sympatric wolf, coyote (Canis latrans), and red fox (Vulpes vulpes) serologic data from YNP, spanning 1991–2007, to identify long-term patterns of pathogen exposure, identify associated risk factors, and examine evidence for disease-induced mortality among wolves for which there were survival data. We found high, constant exposure to canine parvovirus (wolf seroprevalence: 100%; coyote: 94%), canine adenovirus-1 (wolf pups [0.5–0.9 yr]: 91%, adults [≥1 yr]: 96%; coyote juveniles [0.5–1.5 yrs]: 18%, adults [≥1.6 yrs]: 83%), and canine herpesvirus (wolf: 87%; coyote juveniles: 23%, young adults [1.6–4.9 yrs]: 51%, old adults [≥5 yrs]: 87%) suggesting that these pathogens were enzootic within YNP wolves and coyotes. An average of 50% of wolves exhibited exposure to the protozoan parasite, Neospora caninum, although individuals’ odds of exposure tended to increase with age and was temporally variable. Wolf, coyote, and fox exposure to canine distemper virus (CDV) was temporally variable, with evidence for distinct multi-host outbreaks in 1999 and 2005, and perhaps a smaller, isolated outbreak among wolves in the interior of YNP in 2002. The years of high wolf-pup mortality in 1999 and 2005 in the northern region of the park were correlated with peaks in CDV seroprevalence, suggesting that CDV contributed to the observed mortality. Conclusions/Significance Of the pathogens we examined, none appear to jeopardize the long-term population of canids in YNP. However, CDV appears capable of causing short-term population declines. Additional information on how and where CDV is maintained and the frequency with which future epizootics might

  19. Occurrence of tongue worm, Linguatula cf. serrata (Pentastomida: Linguatulidae in wild canids and livestock in south-eastern Australia

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    Shokoofeh Shamsi

    2017-12-01

    Full Text Available Pentastomids are obligate zoonotic arthropod parasites utilising canids and vulpids as their definitive hosts and several herbivorous species as their intermediate hosts. Reported only 10 times in Australia over the last 150 years as incidental findings, adult Pentastomids referred to as Linguatula serrata have been encountered in nasal cavities of domestic and wild dogs, and foxes. Nymphs have been reported in cattle and rabbits. In the present study, a number of potential definitive hosts, including red foxes (Vulpes vulpes, wild dogs (Canis lupus dingo and C.l. dingo x C. familiaris and feral cats (Felis catus, and intermediate hosts cattle (Bos taurus, sheep (Ovis aries, feral pigs (Sus scrofa, rabbits (Oryctolagus cuniculus, goats (Capra hircus and a European hare (Lepus europaeus, from the highlands of south-eastern Australia were examined. Of the animals examined 67.6% of wild dogs (n = 37, 14.5% of red foxes (n = 55 and 4.3% of cattle (n = 164 were found to be infected with Pentastomids, herein identified as Linguatula cf. serrata. The common occurrence of the parasite in wild dogs and less frequently in foxes suggests these wild canids have potential to act as a reservoir for infection of livestock, wildlife, domestic dogs and possibly humans. The unexpected high frequency of the parasite in wild dogs and foxes in south-eastern Australia suggests the parasite is more common than previously realised. Of the potential intermediate hosts in the region, only 4.3% of cattle were found to be infected with pentastomid nymphs which suggest the search for the host(s acting as the main intermediate host in the region should continue. Future studies should investigate transmission patterns, health impacts on hosts and whether the parasite has zoonotic significance in Australia. Keywords: Tongue worm, Australia, Linguatulidae, Pentastomida

  20. Occurrence of tongue worm, Linguatula cf. serrata (Pentastomida: Linguatulidae) in wild canids and livestock in south-eastern Australia.

    Science.gov (United States)

    Shamsi, Shokoofeh; McSpadden, Kate; Baker, Sara; Jenkins, David J

    2017-12-01

    Pentastomids are obligate zoonotic arthropod parasites utilising canids and vulpids as their definitive hosts and several herbivorous species as their intermediate hosts. Reported only 10 times in Australia over the last 150 years as incidental findings, adult Pentastomids referred to as Linguatula serrata have been encountered in nasal cavities of domestic and wild dogs, and foxes. Nymphs have been reported in cattle and rabbits. In the present study, a number of potential definitive hosts, including red foxes (Vulpes vulpes), wild dogs (Canis lupus dingo and C.l. dingo x C. familiaris) and feral cats (Felis catus), and intermediate hosts cattle (Bos taurus), sheep (Ovis aries), feral pigs (Sus scrofa), rabbits (Oryctolagus cuniculus), goats (Capra hircus) and a European hare (Lepus europaeus), from the highlands of south-eastern Australia were examined. Of the animals examined 67.6% of wild dogs (n = 37), 14.5% of red foxes (n = 55) and 4.3% of cattle (n = 164) were found to be infected with Pentastomids, herein identified as Linguatula cf. serrata. The common occurrence of the parasite in wild dogs and less frequently in foxes suggests these wild canids have potential to act as a reservoir for infection of livestock, wildlife, domestic dogs and possibly humans. The unexpected high frequency of the parasite in wild dogs and foxes in south-eastern Australia suggests the parasite is more common than previously realised. Of the potential intermediate hosts in the region, only 4.3% of cattle were found to be infected with pentastomid nymphs which suggest the search for the host(s) acting as the main intermediate host in the region should continue. Future studies should investigate transmission patterns, health impacts on hosts and whether the parasite has zoonotic significance in Australia.

  1. A review on the Late Villafranchian medium-sized canid Canis arnensis based on the evidence from Poggio Rosso (Tuscany, Italy)

    Science.gov (United States)

    Bartolini Lucenti, Saverio; Rook, Lorenzo

    2016-11-01

    The fossil canid material recovered from the Early Pleistocene site of Poggio Rosso offers the opportunity to revise the taxonomical status of the Arno River dog, Canis arnensis. To date, the identification of this species is still a matter of debate due, on the one hand, to the poor state of preservation of the type specimens, and on the other hand to the lack of homogeneous descriptions and a clear diagnosis. The fossils recovered from Poggio Rosso show a good state of preservation with little (if any) plastic deformation, allowing re-evaluation of the dental and cranial characters typical of this species, as well as the proposal, for the first time, of a precise and specific diagnosis. The anatomical and morphometric features of C. arnensis exclude a close taxonomical relationship with the coeval Canis etruscus, suggesting instead a closer affinity to modern canids. The C. arnensis arrived in Italy around 1.9 Ma as the result of a dispersal event, and Poggio Rosso is the first Italian site recording the occurrence of this species. The dispersal of C. arnensis represents the arrival of the first modern canids in Europe and is therefore a significantly important biochronological event in European faunal assemblages.

  2. The physiology of cooperative breeding in a rare social canid; sex, suppression and pseudopregnancy in female Ethiopian wolves.

    Science.gov (United States)

    van Kesteren, Freya; Paris, Monique; Macdonald, David W; Millar, Robert; Argaw, Kifle; Johnson, Paul J; Farstad, Wenche; Sillero-Zubiri, Claudio

    2013-10-02

    Ethiopian wolves, Canis simensis, differ from other cooperatively breeding canids in that they combine intense sociality with solitary foraging, making them a suitable species in which to study the physiology of cooperative breeding. The reproductive physiology of twenty wild female Ethiopian wolves (eleven dominant and nine subordinate) in Ethiopia's Bale Mountains National Park was studied non-invasively through the extraction and assaying of estradiol, progesterone and glucocorticoids in collected fecal samples using enzyme and radioimmunoassays. All dominant females showed increased estradiol concentrations and/or mating behavior during the annual mating season. In contrast, none of the subordinate females showed increased estradiol concentrations or mating behavior during the mating season. However, two subordinate females came into estrus outside of the mating season. Both dominant and subordinate females had higher average progesterone concentrations during the dominant female's pregnancy than at other times of the year, and two subordinate females allosuckled the dominant female's pups. No statistically significant differences in glucocorticoid concentrations were found between dominant and subordinate females. These results suggest that subordinate females are reproductively suppressed during the annual mating season, but may ovulate outside of the mating season and become pseudopregnant. No evidence was found to suggest that reproductive suppression in subordinate females was regulated through aggressive behaviors, and no relationship was found between fecal glucocorticoids and dominance status. © 2013 Elsevier Inc. All rights reserved.

  3. Complete sequence of the Tibetan Mastiff mitochondrial genome and its phylogenetic relationship with other Canids ( Canis, Canidae).

    Science.gov (United States)

    Li, Yinxia; Li, Qifa; Zhao, Xingbo; Xie, Zhuang; Xu, Yinxue

    2011-01-01

    In this study, the complete sequence of the Tibetan Mastiff mitochondrial genome (mtDNA) was determined, and the phylogenetic relationships between the Tibetan Mastiff and other species of Canidae were analyzed using the coyote (Canis latrans) as an outgroup. The complete nucleotide sequence of the Tibetan Mastiff mtDNA was 16 710 bp, and included 22 tRNA genes, 2S rRNA gene, 13 protein-coding genes and one non-coding region (D-loop region), which is similar to other mammalian mitochondrial genomes. The characteristics of the protein-coding genes, non-coding region, tRNA and rRNA genes among Canidae were analyzed in detail. Neighbor-joining and maximum-parsimony trees of Canids constructed using 12 mitochondrial protein-coding genes showed that as the coyotes and Tibetan wolves clustered together, so too did the gray wolves and domestic dogs, suggesting that the Tibetan Mastiff originated from the gray wolf as did other domestic dogs. Domestic dogs clustered into four clades, implying at least four maternal origins (A to D). The Tibetan Mastiff, which belongs to clade A, appears to be closely related to the Saint Bernard and the Old English Sheepdog.

  4. Demography of High-Redshift AGN

    Directory of Open Access Journals (Sweden)

    Fabrizio Fiore

    2012-01-01

    Universe during its infancy. We review the latest searches for high-z AGN in the deepest X-ray field so far, the Chandra Deep Field South (CDFS 4 Msecond exposure. We do not confirm the positive detection of a signal in the stacked Chandra images at the position of z~6 galaxies recently reported by Treister and collaborators (2011. We present z>3 X-ray sources number counts in the 0.5–2 keV band, obtained joining CDFS faint detections (see Fiore et al. (2011, with Chandra-COSMOS and XMM-COSMOS detections. We use these number counts to make predictions for surveys with three mission concepts: Athena, WFXT, and a Super-Chandra.

  5. Studying the high redshift Universe with Athena

    Science.gov (United States)

    O'Brien, P. T.

    2016-04-01

    Athena is the second large mission selected in the ESA Cosmic Vision plan. With its large collecting area, high spectral-energy resolution (X-IFU instrument) and impressive grasp (WFI instrument), Athena will truly revolutionise X-ray astronomy. The most prodigious sources of high-energy photons are often transitory in nature. Athena will provide the sensitivity and spectral resolution coupled with rapid response to enable the study of the dynamic sky. Potential sources include: distant Gamma-Ray Bursts to probe the reionisation epoch and find ‘missing’ baryons in the cosmic web; tidal disruption events to reveal dormant supermassive and intermediate-mass black holes; and supernova explosions to understand progenitors and their environments.Using detailed simulations, we illustrate Athena’s extraordinary capabilities for transients out to the highest redshifts and show how it will be able to constrain the nature of explosive transients including gas metallicity and dynamics, constraining environments and progenitors.

  6. High Redshift Lyman-α Hunt

    DEFF Research Database (Denmark)

    Kochiashvili, Ia

    .85.I used the near-infrared data from NB1060, Y and J filters to perform colour-colourand colour-magnitude selections. With the broad-band data from CANDELS catalogue,I performed SED fitting and derived photometric redshifts and other physical propertiesfor the candidate emission-line galaxies....... Significant differences between the two selectionmethods have been found. The colour-colour selection method, tends to pick galaxieswith high colour excess and can leave some strong emission-line candidates with relativelylower colour excess out of the sample. The populations of selected galaxies can also...... bevery biased. The colour-magnitude selection method picks not only “normal” galaxies,but also starburst ones.I investigated the physical properties and colour indices for the selected galaxies,obtaining the following results. I) Stellar masses for narrow-band selected galaxies arefound...

  7. Protogalaxies. [with early disk and spheroid systems

    Science.gov (United States)

    Cowie, Lennox L.

    1988-01-01

    It is argued that the observed sample of flat-spectrum galaxies seen in recent deep surveys must contain both early disk systems and early spheroid systems in order to match observed number counts if q sub 0 = 0.5. The low average density of neutral hydrogen in damped L-alpha systems at z = 2 - 3 separates the disk formation at z less than about 2 from spheroid formation at z greater than about 3. Based on color arguments, the period of spheroid formation is assigned to z = 4.

  8. A robust morphological classification of high-redshift galaxies using support vector machines on seeing limited images. II. Quantifying morphological k-correction in the COSMOS field at 1 < z < 2: Ks band vs. I band

    Science.gov (United States)

    Huertas-Company, M.; Tasca, L.; Rouan, D.; Pelat, D.; Kneib, J. P.; Le Fèvre, O.; Capak, P.; Kartaltepe, J.; Koekemoer, A.; McCracken, H. J.; Salvato, M.; Sanders, D. B.; Willott, C.

    2009-04-01

    Context: Morphology is the most accessible tracer of galaxies physical structure, but its interpretation in the framework of galaxy evolution still remains problematic. Its quantification at high redshift requires deep high-angular resolution imaging, which is why space data (HST) are usually employed. At z > 1, the HST visible cameras however probe the UV flux, which is dominated by the emission of young stars, which could bias the estimated morphologies towards late-type systems. Aims: In this paper we quantify the effects of this morphological k-correction at 1 Methods: In Paper I we presented a new non-parametric method of quantifying morphologies of galaxies on seeing-limited images based on support vector machines. Here we use this method to classify ~50 000 Ks selected galaxies in the COSMOS area observed with WIRCam at CFHT. We use a 10-dimensional volume, including 5 morphological parameters, and other characteristics of galaxies such as luminosity and redshift. The obtained classification is used to investigate the redshift distributions and number counts per morphological type up to z ~ 2 and to compare them to the results obtained with HST/ACS in the I-band on the same objects. We associate to every galaxy with Ks find less early-type galaxies than the Ks-band one by a factor ~1.5, which might be a consequence of morphological k-correction effects. Conclusions: We argue therefore that studies based on I-band HST/ACS classifications at z > 1 could be underestimating the elliptical population. Using our method in a Ks ≤ 21.5 magnitude-limited sample, we observe that the fraction of the early-type population is (21.9% ± 8%) at z ~ 1.5-2 and (32.0% ± 5%) at the present time. We will discuss the evolution of the fraction of galaxies in types from volume-limited samples in a forthcoming paper. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des

  9. The role of wild canids and felids in spreading parasites to dogs and cats in Europe. Part I: Protozoa and tick-borne agents.

    Science.gov (United States)

    Otranto, Domenico; Cantacessi, Cinzia; Pfeffer, Martin; Dantas-Torres, Filipe; Brianti, Emanuele; Deplazes, Peter; Genchi, Claudio; Guberti, Vittorio; Capelli, Gioia

    2015-09-30

    Over the last few decades, the world has witnessed radical changes in climate, landscape, and ecosystems. These events, together with other factors such as increasing illegal wildlife trade and changing human behaviour towards wildlife, are resulting into thinning boundaries between wild canids and felids and their domestic counterparts. As a consequence, the epidemiology of diseases caused by a number of infectious agents is undergoing profound readjustements, as pathogens adapt to new hosts and environments. Therefore, there is a risk for diseases of wildlife to spread to domestic carnivores and vice versa, and for zoonotic agents to emerge or re-emerge in human populations. Hence, the identification of the hazards arising from the co-habitation of these species is critical in order to plan and develop adequate control strategies against these pathogens. In the first of this two-part article, we review the role that wild canids and felids may play in the transmission of protozoa and arthropod-borne agents to dogs and cats in Europe, and provide an account of how current and future progress in our understanding of the ecology and epidemiology of parasites, as well as of host-parasite interactions, can assist efforts aimed at controlling parasite transmission. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Cloning and comparative analysis of zinc-finger protein gene on Y-chromosome (ZFY between Thai Bangkaew dog and other Thai canids

    Directory of Open Access Journals (Sweden)

    Ukadej Boonyaprakob

    2017-06-01

    Full Text Available The Thai Bangkaew dog is a Spitz-type dog that originated in Thailand. Legend has it that the dog is descended from hybrids between a native female dog and a male wild canid. To examine the mysterious story about the ancestry of the Thai Bangkaew dog's paternal lineage, sequence variation was examined for the last intron of the Y-chromosome-specific zinc-finger gene, ZFY, and its X homolog for male Thai Bangkaew dogs and other male Thai canids, including the Thai ridgeback and mixed breed dogs, Asiatic jackals (Canis aureus and a dhole (Cuon alpinus. A 1075-bp ZFY segment from DNA samples of Thai Bangkaew dogs was found to be 100% identical to the domestic dog ZFY and (if gaps are allowed showed 81% and 92% identity to jackal ZFY and dhole ZFY, respectively. However, if gaps were treated as missing data, the 1045-bp ZFY sequence for the Thai Bangkaew dogs was 100% identical to domestic dog ZFY and 99.5% to jackal ZFY and dhole ZFY, respectively. In addition, the 959-bp Thai Bangkaew ZFX fragments were identical and showed 100% identity to domestic dog ZFX. These genetic data suggest that the Thai Bangkaew dogs still present today share a common male ancestor with modern dogs, rather than being the descendants of dhole or jackal/dog hybrids.

  11. Patterns of MHC-DRB1 polymorphism in a post-glacial island canid, the Newfoundland red fox (Vulpes vulpes deletrix), suggest balancing selection at species and population timescales.

    Science.gov (United States)

    Marshall, H Dawn; Langille, Barbara L; Hann, Crystal A; Whitney, Hugh G

    2016-05-01

    As the only native insular Newfoundland canid between the extinction of the wolf in the 1930s and the recent arrival of coyotes, the red fox (Vulpes vulpes deletrix Bangs 1898) poses interesting questions about genetic distinctiveness and the post-glacial colonization history of the island's depauperate mammalian fauna. Here, we characterized genetic variability at the major histocompatibility complex (MHC) class II DR β1 domain (DRB1) locus in 28 red foxes from six sampling localities island-wide and compared it with mitochondrial control region (CR) diversity and DRB1 diversity in other canids. Our goals were to describe novel DRB1 alleles in a new canid population and to make inferences about the role of selection in maintaining their diversity. As in numerous studies of vertebrates, we found an order-of-magnitude higher nucleotide diversity at the DRB1 locus compared with the CR and significantly positive nonsynonymous-to-synonymous substitution ratios, indicative of selection in the distant past. Although the evidence is weaker, the Ewens-Watterson test of neutrality and the geographical distribution of variation compared with the CR suggest a role for selection over the evolutionary timescale of populations. We report the first genetic data from the DRB1 locus in the red fox and establish baseline information regarding immunogenetic variation in this island canid population which should inform continued investigations of population demography, adaptive genetic diversity, and wildlife disease in red foxes and related species.

  12. Tracking the origins and diet of an endemic island canid (Urocyon littoralis) across 7300 years of human cultural and environmental change

    Science.gov (United States)

    Hofman, Courtney A.; Rick, Torben C.; Maldonado, Jesús E.; Collins, Paul W.; Erlandson, Jon M.; Fleischer, Robert C.; Smith, Chelsea; Sillett, T. Scott; Ralls, Katherine; Teeter, Wendy; Vellanoweth, René L.; Newsome, Seth D.

    2016-08-01

    Understanding how human activities have influenced the foraging ecology of wildlife is important as our planet faces ongoing and impending habitat and climatic change. We review the canine surrogacy approach (CSA)-a tool for comparing human, dog, and other canid diets in the past-and apply CSA to investigate possible ancient human resource provisioning in an endangered canid, the California Channel Islands fox (Urocyon littoralis). We conducted stable isotope analysis of bone collagen samples from ancient and modern island foxes (n = 214) and mainland gray foxes (Urocyon cinereoargenteus, n = 24). We compare these data to isotope values of ancient humans and dogs, and synthesize 29 Accelerator Mass Spectrometry (AMS) radiocarbon dates that fine-tune the chronology of island foxes. AMS dates confirm that island foxes likely arrived during the early Holocene (>7300 cal BP) on the northern islands in the archipelago and during the middle Holocene (>5500 cal BP) on the southern islands. We found no evidence that island foxes were consistently using anthropogenic resources (e.g., food obtained by scavenging around human habitation sites or direct provisioning by Native Americans), except for a few individuals on San Nicolas Island and possibly on San Clemente and Santa Rosa islands. Decreases in U. littoralis carbon and nitrogen isotope values between prehistoric times and the 19th century on San Nicolas Island suggest that changes in human land use from Native American hunter-gatherer occupations to historical ranching had a strong influence on fox diet. Island foxes exhibit considerable dietary variation through time and between islands and have adapted to a wide variety of climatic and cultural changes over the last 7300 years. This generalist foraging strategy suggests that endemic island foxes may be resilient to future changes in resource availability.

  13. The role of wild canids and felids in spreading parasites to dogs and cats in Europe. Part II: Helminths and arthropods.

    Science.gov (United States)

    Otranto, Domenico; Cantacessi, Cinzia; Dantas-Torres, Filipe; Brianti, Emanuele; Pfeffer, Martin; Genchi, Claudio; Guberti, Vittorio; Capelli, Gioia; Deplazes, Peter

    2015-09-30

    Over the last few decades, ecological factors, combined with everchanging landscapes mainly linked to human activities (e.g. encroachment and tourism) have contributed to modifications in the transmission of parasitic diseases from domestic to wildlife carnivores and vice versa. In the first of this two-part review article, we have provided an account of diseases caused by protozoan parasites characterised by a two-way transmission route between domestic and wild carnivore species. In this second and final part, we focus our attention on parasitic diseases caused by helminth and arthropod parasites shared between domestic and wild canids and felids in Europe. While a complete understanding of the biology, ecology and epidemiology of these parasites is particularly challenging to achieve, especially given the complexity of the environments in which these diseases perpetuate, advancements in current knowledge of transmission routes is crucial to provide policy-makers with clear indications on strategies to reduce the impact of these diseases on changing ecosystems. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Association of MC3R gene polymorphisms with body weight in the red fox and comparative gene organization in four canids.

    Science.gov (United States)

    Skorczyk, A; Flisikowski, K; Szydlowski, M; Cieslak, J; Fries, R; Switonski, M

    2011-02-01

    There are five genes encoding melanocortin receptors. Among canids, the genes have mainly been studied in the dog (MC1R, MC2R and MC4R). The MC4R gene has also been analysed in the red fox. In this report, we present a study of chromosome localization, comparative sequence analysis and polymorphism of the MC3R gene in the dog, red fox, arctic fox and Chinese raccoon dog. The gene was localized by FISH to the following chromosome: 24q24-25 in the dog, 14p16 in the red fox, 18q13 in the arctic fox and NPP4p15 in the Chinese raccoon dog. A high identity level of the MC3R gene sequences was observed among the species, ranging from 96.0% (red fox--Chinese raccoon dog) to 99.5% (red fox--arctic fox). Altogether, eight polymorphic sites were found in the red fox, six in the Chinese raccoon dog and two in the dog, while the arctic fox appeared to be monomorphic. In addition, association of several polymorphisms with body weight was analysed in red foxes (the number of genotyped animals ranged from 319 to 379). Two polymorphisms in the red fox, i.e. a silent substitution c.957A>C and c.*185C>T in the 3'-flanking sequence, showed a significant association (P < 0.01) with body weight. © 2010 The Authors, Animal Genetics © 2010 Stichting International Foundation for Animal Genetics.

  15. Mitochondrial Analysis of the Most Basal Canid Reveals Deep Divergence between Eastern and Western North American Gray Foxes (Urocyon spp. and Ancient Roots in Pleistocene California.

    Directory of Open Access Journals (Sweden)

    Natalie S Goddard

    Full Text Available Pleistocene aridification in central North America caused many temperate forest-associated vertebrates to split into eastern and western lineages. Such divisions can be cryptic when Holocene expansions have closed the gaps between once-disjunct ranges or when local morphological variation obscures deeper regional divergences. We investigated such cryptic divergence in the gray fox (Urocyon cinereoargenteus, the most basal extant canid in the world. We also investigated the phylogeography of this species and its diminutive relative, the island fox (U. littoralis, in California. The California Floristic Province was a significant source of Pleistocene diversification for a wide range of taxa and, we hypothesized, for the gray fox as well. Alternatively, gray foxes in California potentially reflected a recent Holocene expansion from further south. We sequenced mitochondrial DNA from 169 gray foxes from the southeastern and southwestern United States and 11 island foxes from three of the Channel Islands. We estimated a 1.3% sequence divergence in the cytochrome b gene between eastern and western foxes and used coalescent simulations to date the divergence to approximately 500,000 years before present (YBP, which is comparable to that between recognized sister species within the Canidae. Gray fox samples collected from throughout California exhibited high haplotype diversity, phylogeographic structure, and genetic signatures of a late-Holocene population decline. Bayesian skyline analysis also indicated an earlier population increase dating to the early Wisconsin glaciation (~70,000 YBP and a root height extending back to the previous interglacial (~100,000 YBP. Together these findings support California's role as a long-term Pleistocene refugium for western Urocyon. Lastly, based both on our results and re-interpretation of those of another study, we conclude that island foxes of the Channel Islands trace their origins to at least 3 distinct female

  16. Strong magnetic fields in normal galaxies at high redshift

    Science.gov (United States)

    Bernet, Martin L.; Miniati, Francesco; Lilly, Simon J.; Kronberg, Philipp P.; Dessauges-Zavadsky, Miroslava

    2008-07-01

    The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few constraints on the timescale. It was recently demonstrated that field strengths as traced by rotation measures of distant (and hence ancient) quasars are comparable to those seen today, but it was unclear whether the high fields were in the unusual environments of the quasars themselves or distributed along the lines of sight. Here we report high-resolution spectra that demonstrate that the quasars with strong MgII absorption lines are unambiguously associated with larger rotation measures. Because MgII absorption occurs in the haloes of normal galaxies along the sightlines to the quasars, this association requires that organized fields of surprisingly high strengths are associated with normal galaxies when the Universe was only about one-third of its present age.

  17. Nature of the Background Ultraviolet Radiation Field at High Redshifts

    Indian Academy of Sciences (India)

    tribpo

    thus necessary for the understanding of the early universe. AGNs are believed to be the major ... This ratio is insensitive to the particle density and the abundance of carbon, but is very sensitive to the ..... assuming the rest of the required flux to be of local, galactic origin, very high galactic flux is required. For most of the ...

  18. From Nearby Low Luminosity AGN to High Redshift Radio Galaxies ...

    Indian Academy of Sciences (India)

    Amity Institute of Applied Sciences, Amity University Uttar Pradesh, Sector-125, Noida, India. Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380 009, India. Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560 080, India. Centre de Recherche Astrophysique de ...

  19. Predicting the High Redshift Galaxy Population for JWST

    Science.gov (United States)

    Flynn, Zoey; Benson, Andrew

    2017-01-01

    The James Webb Space Telescope will be launched in Oct 2018 with the goal of observing galaxies in the redshift range of z = 10 - 15. As redshift increases, the age of the Universe decreases, allowing us to study objects formed only a few hundred million years after the Big Bang. This will provide a valuable opportunity to test and improve current galaxy formation theory by comparing predictions for mass, luminosity, and number density to the observed data. We have made testable predictions with the semi-analytical galaxy formation model Galacticus. The code uses Markov Chain Monte Carlo methods to determine viable sets of model parameters that match current astronomical data. The resulting constrained model was then set to match the specifications of the JWST Ultra Deep Field Imaging Survey. Predictions utilizing up to 100 viable parameter sets were calculated, allowing us to assess the uncertainty in current theoretical expectations. We predict that the planned UDF will be able to observe a significant number of objects past redshift z > 9 but nothing at redshift z > 11. In order to detect these faint objects at redshifts z = 11-15 we need to increase exposure time by at least a factor of 1.66.

  20. Spitzer's View of Galaxies in the High-Redshift Universe

    Science.gov (United States)

    Fazio, Giovanni G.

    One of the most important observations made by the Spitzer Space Telescope has been the detection of luminous galaxies back to the era of reionization (z ~ 8), when the universe was less than 700 million years old. The key advance made by Spitzer imaging isthe ability, for the first time, to sample the redshifted rest-frame visible light of these galaxies. When combined with broadband multi-wavelength data, Spitzer observations can be fit to stellar population synthesis models to determine the spectral energy distribution of these galaxies and to constrain their stellar masses and ages and their star formation histories. As a result, there is evidence that most of the stellar mass of these galaxies formed at even higher redshifts (z > 10 to 12) and that asignificant number of galaxies should exist in this region.Searches for galaxies at z ~ 9 to 10 continue. Spitzer observations of massive lensing clusters have also played a pivotal role in this study. The first IRAC detection of a z >6 galaxy came from such observations. Since most of these results were obtained with Spitzer/IRAC 3.6/4.5 μm bands, the Spitzer Warm Mission, when combined with future HST/WFC3 observations, will provide a unique opportunity to obtain the first complete census of the assembly of stellar mass as a function of cosmic time back to the era of reionization, yielding unique information on galaxy formation in the early universe.

  1. Are high-redshift quasars hidden by dusty galaxies?

    Science.gov (United States)

    Wright, Edward L.

    1990-04-01

    A Monte Carlo technique has been developed to compute the joint probability distribution for the reddening and extinction of quasars by galaxies along the line of sight with a realistic dust extinction curve including the 220 nm feature. Galaxies are treated as disks with random inclinations, having exponential or modified Gaussian radial profiles. This technique is used to find the distribution of the reddened quasars on multicolor diagrams such as the (U-J, J-F) plots used by Koo and Kron (1982) to find faint quasars. The multicolor search technique is not a simple UV excess approach, and the resulting color selection does not add significantly to the flux selection discussed by Wright (1981), Ostriker and Heisler (1984), and Heisler and Ostriker (1988). The quasar reddening trend observed by Wright and Malkan (1987) is about 0.35 + or - 0.50 times the mean reddening of the selected sample predicted by the Heisler and Ostriker model.

  2. Selection and Physical Properties of High-redshift Galaxies

    Science.gov (United States)

    Fang, G. W.

    2014-09-01

    Extremely Red Objects (EROs) and BzKs continue to attract considerable interest. It has been suggested that they may be the direct progenitors of present-day massive E/S0 galaxies, and can provide crucial constraints on the current galaxy formation and evolution models. Therefore, the key question is to measure the relative fraction of OGs (old galaxies) and DGs (young, and dusty starburst galaxies) in the sample of EROs. Many groups have been currently investigating the fractions of these two ERO populations using a variety of observational approaches, but the fraction of OGs and DGs from different surveys is different. In the meantime, a number of observations suggest that the epoch of z˜2 also plays an important role in galaxy formation and evolution for various reasons: the cosmic star formation rate density (SFRD) begins to drop at z˜2 from a flat plateau at higher redshifts; the morphological type mix of field galaxies changes remarkably at z˜2; the number density of QSOs has a peak at z˜2; and about 50% to 70% of the stellar mass assembly of galaxies took place in the redshift range 1UDF and COSMOS field, (2) a study on physical properties of passive and star-forming galaxies at z˜2 in the AEGIS field, and (3) the mid-infrared spectroscopy and multi-wavelength study of ultraluminous infrared galaxies (ULIRGs) at z˜2 in the AEGIS field. Chapter 1 gives a brief review on the research progresses of EROs at z˜1, BzKs at z˜2, and ULIRGs at z˜2, respectively. In Chapter 2 we present a quantitative study of the classification of EROs in the UDF and COSMOS field. Our sample includes 5264 (COSMOS, K_{Vega} ≤19.2) and 24 EROs (UDF, K_{Vega}≤22.0) with (i-K)_{AB}≥2.45. Using the fitting method of spectral energy distribution (SED), [3.6]-[8.0] color, and the nonparametric measures of galaxy morphology, we classify EROs into two classes: DGs and OGs. We find that the fraction of OGs and DGs in our sample (COSMOS) is similar, about 52% of them are DGs, and the other 48% are OGs. For 24 EROs in the UDF, 16 fall into DGs, while 8 are OGs. To reduce the redundancy of these three different classification methods, we perform a principal component analysis on the measurements of EROs, and find that the nonparametric measures and SEDs are efficient in segregating DGs and OGs. We investigate the dependence of the fraction of EROs on their observational properties, and the results suggest that DGs become increasingly important toward fainter magnitudes, redder colors, and higher redshifts. Moreover, we find that the clustering of EROs is much stronger than that of full K-limited samples of galaxies; and the clustering amplitude of OGs is a factor of ˜2 larger than DGs. In Chapter 3, we pick out 1609 star-forming galaxies (sgzKs: gzK=(z-K)_{AB}-1.4(g-z)_{AB}≥ 0.2) and 422 passively evolving galaxies (pgzKs: gzK2.7) at z˜2 in the AEGIS field (K_{AB} 10^{11} M_{⊙} and 410 M_⊙\\cdot yr^{-1}< SFR <1022 M_⊙\\cdot yr^{-1}, respectively. Their rest-frame optical morphologies are very diversified including string-like, extended/diffused, and even early type spiral morphologies, implying that there are different formation processes for these galaxies. We also search for active galactic nucleus (AGN) signature in our sample using X-ray, radio, and mid-infrared (MIR) observations. EGS22, EGS25, EGS27, and EGS34 are detected in the X-ray imaging. The X-ray luminosities for EGS22 and EGS34 can be accounted for by their intensive star formation. EGS25 and EGS27 have higher L_{2-10 keV}, indicating that they harbor AGNs. About 14% to 29% of the sample show signatures of AGNs in X-ray, MIR or radio. Finally, the summary of the whole thesis and outlook are presented in Chapter 5.

  3. On the Number of Galaxies at High Redshift

    Directory of Open Access Journals (Sweden)

    Lorenzo Zaninetti

    2015-09-01

    Full Text Available The number of galaxies at a given flux as a function of the redshift, z, is derived when the z-distance relation is non-standard. In order to compare different models, the same formalism is also applied to the standard cosmology. The observed luminosity function for galaxies of the zCOSMOS catalog at different redshifts is modeled by a new luminosity function for galaxies, which is derived by the truncated beta probability density function. Three astronomical tests, which are the photometric maximum as a function of the redshift for a fixed flux, the mean value of the redshift for a fixed flux, and the luminosity function for galaxies as a function of the redshift, compare the theoretical values of the standard and non-standard model with the observed value. The tests are performed on the FORS Deep Field (FDF catalog up to redshift z = 1.5 and on the zCOSMOS catalog extending beyond z = 4. These three tests show minimal differences between the standard and the non-standard models.

  4. Stellar Population Maps of High-Redshift Galaxies

    Science.gov (United States)

    Fetherolf, Tara; Reddy, Naveen; MOSDEF

    2016-06-01

    A comprehensive study of resolved galaxy structure can shed light on the formation and evolution of galactic properties, such as the distribution of stars and interstellar dust that obscures starlight. This requires high-resolution, multi-waveband photometry and spectroscopy to completely characterize the galaxies. Previous studies lacked key spectroscopic information, were comprised of small samples, or focused on the local universe. We use HST ACS/WFC3 high-resolution, multi-waveband imaging from the CANDELS project in parallel with moderate-resolution Keck I MOSFIRE spectra from the MOSFIRE Deep Evolution Field (MOSDEF) survey to produce resolved stellar population and dust maps of ~500 galaxies at redshifts 1.4 < z < 2.6—covering the key epoch when galaxies accreted most of their mass. For data preparation and analysis we develop an automated Python program to process our large, comprehensive dataset. From the multi-waveband imaging and spectroscopic redshifts, we model the spectral energy distribution for every resolution element within each galaxy and compare these results to the spectroscopically measured global properties. From our stellar population and dust maps we identify resolved structures within these galaxies. We also investigate if spectroscopically measured galaxy properties are biased when compared with that of localized sub-galactic structures.

  5. Stellar populations a guide from low to high redshift

    CERN Document Server

    Renzini, Alvio

    2011-01-01

    This up-to-date reference on stellar populations and development models includes coverage of distant galaxies, chemical evolution and supernovae. Written by highly acclaimed authorities in the field, the book makes use of specific problems to reveal the ""kitchen secrets.""

  6. High-Redshift Radio Galaxies from Deep Fields

    Indian Academy of Sciences (India)

    2016-01-27

    2. National Centre for Radio Astrophysics, Post Bag No. 3, Ganeshkind, Pune 411 007, India. International Centre for Radio Astronomical Research, University of Western Australia, Perth, Western Australia, Australia.

  7. Calan Tololo Survey: Bright Quasars at High Redshifts

    Science.gov (United States)

    Maza, Jose; Ruiz, Maria Teresa; Gonzalez, Luis E.; Wischnjewsky, Marina

    An objective prism survey has been started at Cerro Tololo Inter-American Observatory using the thin UV prism (1,360 Å/mm at Hγ and 1,740 Å/mm at Hβ) on the Curtis Schmidt telescope. Unfiltered baked IIIaJ plates exposed 90 minutes have been obtained for 163 fields. Unwiden spectra taken in good seeing reach B ≅ 19. This survey is an extension of the original Tololo survey (Smith 1975; Smith, Aguirre and Zemelman 1986).

  8. Radio imaging of core-dominated high redshift quasars

    NARCIS (Netherlands)

    Barthel, PD; Vestergaard, M; Lonsdale, CJ

    VLA imaging at kiloparsec-scale resolution of sixteen core-dominated radio-loud QSOs is presented. Many;objects appear to display variable radio emission and their radio morphologies are significantly smaller than those of steep-spectrum quasars, consistent with these objects being observed at sight

  9. Simulating the [CII] emission of high redshift galaxies

    DEFF Research Database (Denmark)

    Olsen, Karen Pardos; Greve, Thomas Rodriguez; Narayanan, Desika

    2016-01-01

    and radiative transfer, the photoionization code CLOUDY isimplemented. I will show results for z=2 star-forming galaxies yet to beobserved, as well as preliminary results for galaxies at z~6-7 whereobservations have presented contradictory detections and non-detectionsof star-forming galaxies.......he fine structure line of [CII] at 158 microns can arise throughout theinterstellar medium (ISM) and has been proposed as a tracer of starformation rate (SFR). But the origin of [CII] and how it depends on e.g.metallicity and radiation field of a galaxy remain uncertain.Simulating[CII] can be done...... by combining the output from galaxy simulations withprescriptions for the subgrid physics, as has now been demonstrated byseveral groups. However, these models are either built on analyticaldiscs or contain other simplifying assumptions. SÍGAME (Simulatorof GAlaxy Millimeter/submillimeter emission) avoids...

  10. Simulating the [CII] emission of high redshift galaxies

    DEFF Research Database (Denmark)

    Pardos Olsen, Karen; Greve, Thomas Rodriguez; Narayanan, Desika

    2016-01-01

    The fine structure line of [CII] at 158 microns can arise throughout the interstellar medium (ISM) and has been proposed as a tracer of star formation rate (SFR). But the origin of [CII] and how it depends on e.g. metallicity and radiation field of a galaxy remain uncertain.Simulating [CII] can...... be done by combining the output from galaxy simulations with prescriptions for the subgrid physics, as has now been demonstrated by several groups. However, these models are either built on analytical discs or contain other simplifying assumptions. SÍGAME (Simulator of GAlaxy Millimeter....../submillimeter emission) avoids these issues by using cosmological simulations and calculates [CII] emission reliably on resolved scales within each galaxy. The local metallicity is that of the simulation, whereas the far-ultraviolet radiation field and cosmic ray intensity are both scaled with local star formation rate...

  11. From Nearby Low Luminosity AGN to High Redshift Radio Galaxies ...

    Indian Academy of Sciences (India)

    'radio-quiet' AGN (Croton et al. 2006; Best & Heckman 2012). There is also evidence to suggest that galaxy mergers influence the radio-loudness of sources (Heckman et al. 1986; Deane et al. 2014). We know that galaxy mergers are an important phase of galaxy evolution (Schweizer 1982; Mihos & Hernquist. 1996; Cox et ...

  12. Kinematics of a high-redshift galaxy: A case study

    Directory of Open Access Journals (Sweden)

    Ćirković M.M.

    2000-01-01

    Full Text Available A kinematics of a z = 2.81 galaxy toward bright QSO 0528-250, as inferred from the absorption spectroscopy is discussed. There are sufficient arguments for a far-reaching conclusion that we are observing an older, uninvolved version of the local Galactic interstellar medium.

  13. A spectroscopic study of the high-redshift Universe

    NARCIS (Netherlands)

    Karman, Wouter

    2016-01-01

    Galaxies are systems in which stars are formed out of gas and dust. In each galaxy, millions to hundreds of billions of stars reside and evolve as time moves on. The first galaxies were probably formed as early as 200 million years after the Big Bang, in other words, 13.6 billion years ago. Young

  14. Was Star-Formation Suppressed in High-Redshift Minihalos?

    OpenAIRE

    Haiman, Zoltan; Bryan, Greg L.

    2006-01-01

    The primordial gas in the earliest dark matter halos, collapsing at redshifts around z=20, with masses M_halo=10^6 M_sun, and virial temperatures T_vir 10^4K). This conclusion is insensitive to assumptions about the efficiency of ionizing photon production in the large halos, as long as reionization ends by z=6, as required by the spectra of bright quasars at z

  15. Host galaxies of high-redshift quasars with extreme outflows

    Science.gov (United States)

    Zakamska, Nadia

    2016-10-01

    Feedback from accreting supermassive black holes is now a standard ingredient in galaxy formation models. It has long been speculated that powerful quasars, triggered in major gas-rich mergers, had a profound impact on galaxy formation via quasar-driven winds. This process must have been at its peak during the epoch of most active galaxy formation and quasar activity at z=2-3, yet there is not yet any direct observational support for this long-hypothesized process. We have discovered a population of extremely luminous (L>1e47 erg/s) red quasars with peculiar line properties at z=2-3 which show unprecedented signatures of powerful v>2000 km/s outflows in their [OIII]5007A lines. We propose to image eleven of these objects with the HST in two filters, one probing rest-frame UV and one probing the rest-frame optical. The rest-frame optical observations will directly probe the dynamical state and extent of the hosts of luminous obscured quasars and search for companions and merger signatures. We will determine the masses of the stellar component to determine if the bulges of the quasar hosts have already become apparent in this epoch. Using the rest-frame UV observations, we will probe the distribution of the gas in quasar hosts by observing the morphology of ongoing star formation and scattered light from the central engine. Our targets are the best candidates to probe the long-speculated merger-driven scenario for quasar activity, and our proposed HST observations will definitively determine whether this process drives the evolution of massive galaxies.

  16. Pair creation supernovae at low and high redshift

    NARCIS (Netherlands)

    Langer, N.|info:eu-repo/dai/nl/304829498; Norman, C.A.; de Koter, A.; Vink, J.|info:eu-repo/dai/nl/182880559; Cantiello, M.|info:eu-repo/dai/nl/304840866; Yoon, S.C.|info:eu-repo/dai/nl/266576753

    2007-01-01

    Aims:Pair creation supernovae (PCSN) are thought to be produced from very massive low metallicity stars. The spectacularly bright SN 2006gy does show several signatures expected from PCSNe. Here, we investigate the metallicity threshold below which PCSN can form and estimate their occurrence rate.

  17. Pair creation supernovae at low and high redshift

    NARCIS (Netherlands)

    Langer, N.; Norman, C.A.; de Koter, A.; Vink, J.S.; Cantiello, M.; Yoon, S.C.

    2007-01-01

    Aims.Pair creation supernovae (PCSN) are thought to be produced from very massive low metallicity stars. The spectacularly bright SN 2006gy does show several signatures expected from PCSNe. Here, we investigate the metallicity threshold below which PCSN can form and estimate their occurrence rate.

  18. FROM NEARBY LOW LUMINOSITY AGN TO HIGH REDSHIFT ...

    Indian Academy of Sciences (India)

    44

    galaxies exhibited primarily two radio morphologies: the. Fanaroff-Riley (FR) type I galaxies had broad jets that flared into diffuse radio plumes / lobes, while the FR type II galaxies had collimated jets that terminated in regions of high surface brightness called “hot spots” with the back-flowing plasma or the plasma left behind ...

  19. Opening the low frequency window to the high redshift Universe

    NARCIS (Netherlands)

    Vedantham, Harish

    2015-01-01

    The epoch of formation of the first luminous structures (stars and galaxies) called the Comic Dawn, is one of the last unexplored periods in the history of the Universe. A new generation of radio telescopes such as LOFAR aim to revolutionize our understanding of structure formation in the early

  20. Mining the Infrared Sky for High-Redshift Quasars

    Science.gov (United States)

    Richards, Gordon

    The Spitzer and WISE satellites have opened up new avenues for the study of active galactic nuclei (AGN) by peering through the dust shrouding half (or more) of AGNs. However, despite being more sensitive to shrouded AGNs, current selection methods being used in the mid-IR are still largely blind to the highest redshift quasars-both those that are shrouded and those that are not (and should therefore be easy to find). We describe projects to identify both unobscured (at z>3) and obscured quasars (at z>2) that have heretofore been missed in significant numbers. Finding the high-z obscured quasars in large numbers is crucial for fulfilling the legacy of NASA missions in the IR and X-ray. With these quasars we will be able to perform clustering analyses that break the degeneracy of models describing how black holes can ``feed back" energy to the large-scale host galaxy, significantly influencing its evolution. We will further trace the luminosity function of galaxies undergoing active accretion from low-luminosity AGNs to luminous quasars—probing the growth of the supermassive black holes that we see today in the local universe. Our new insights come about from leveraging new Spitzer data, primarily from the PI's SpitzerIRAC Equatorial Survey (SpIES). The Spitzer data are 2.5 magnitudes deeper than the "AllWISE" survey in a 125 square degree, multiwavelength-rich, equatorial region known as SDSS "Stripe 82". These data are crucial for extending mid-IR investigations to higher redshifts, both for unobscured and obscured sources. The PI's team are among the world's experts in using the proposed machine learning techniques to find both unobscured (type-1) and obscured (type- 2) quasars and in using quasar clustering and luminosity functions to do cutting-edge science. The luminosity function and clustering algorithms are already in place, allowing for timely completion of this project once the multi-wavelength NASA data have been incorporated. This project is directly relevant to our understanding of the evolution of galaxies and to NASA's goal of better understanding the Universe. Moreover, NASA's data archive is crucial to the project: it is only by using data from Spitzer and WISE that will allow us to more fully understand the physics of quasars—by probing them at epochs where they are both most difficult to find, but also the most influential.

  1. Radio imaging of core-dominated high redshift quasars

    DEFF Research Database (Denmark)

    Barthel, Peter D.; Vestergaard, Marianne; Lonsdale, Colin J.

    1999-01-01

    VLA imaging at kiloparsec-scale resolution of sixteen core-dominated radio-loud QSOs is presented. Many objects appear to display variable radio emission and their radio morphologies are significantly smaller than those of steep-spectrum quasars, consistent with these objects being observed...... at sight lines close to their (relativistic, $\\gamma \\approx$ 4-7) jet axes. The usefulness of the radio source orientation indicator R_V, being defined as ratio of radio core and rest frame optical V-band luminosity, is confirmed....

  2. High-Redshift Compton Thick AGN with EXIST

    Science.gov (United States)

    Treister, Ezequiel; Urry, C.; Coppi, P.; Virani, S.

    2009-01-01

    It has been suspected for many years that a large number of heavily obscured, Compton Thick, Active Galactic Nuclei (AGN) should exist at all redshifts, but the exact number of them is still highly uncertain. Recent all-sky surveys with INTEGRAL and Swift are starting to constrain the number of Compton Thick AGN in the local Universe, zEXIST observations. We expect to find a total of 120 Compton Thick AGN at 0.5

  3. Leishmania (Leishmania infantum chagasi em canídeos silvestres mantidos em cativeiro, no Estado de Mato Grosso Leishmania (Leishmania infantum chagasi in wild canids kept in captivity in the State of Mato Grosso

    Directory of Open Access Journals (Sweden)

    Nely Pinheiro Souza

    2010-06-01

    Full Text Available INTRODUÇÃO: Leishmaniose visceral é uma zoonose que acomete diversos mamíferos tendo os canídeos domésticos como principais reservatórios em ambiente urbano. A presente nota descreve a infecção de canídeos silvestres por Leishmania (Leishmania infantum chagasi mantidos em cativeiro no Estado de Mato Grosso, Brasil. MÉTODOS: De seis raposas (Cerdocyon thous e um cachorro vinagre (Spheotos venaticus, foram coletadas amostras de pele, medula óssea e linfonodo para detecção e caracterização de Leishmania sp pela técnica de PCR-RFLP. RESULTADOS: Todos as animais pesquisados apresentaram-se positivos para Leishmania (L. infantum chagasi. CONCLUSÕES: Destaca-se a importância de monitoramento adequado dos mesmos, além do maior controle desta enfermidade já que estes animais estão em ambientes de recreação pública.INTRODUCTION: Visceral leishmaniasis is a zoonosis that affects many mammals, and domestic canids are the main reservoirs in urban environments. This note describes infection by Leishmania (Leishmania infantum chagasi among wild canids kept in captivity in the State of Mato Grosso, Brazil. METHODS: Skin, bone marrow and lymph node samples were collected from six crab-eating foxes (Cerdocyon thous and one bush dog (Spheotos venaticus, in order to detect and characterize Leishmania using the PCR-RFLP technique. RESULTS: All the animals studied were positive for Leishmania (L. infantum chagasi. CONCLUSIONS: This study highlights the importance of adequate monitoring of these animals, as well as greater control of this disease, given that these animals are in a public recreation environment.

  4. Teste de ELISA indireto para diagnóstico sorológico de leishmaniose visceral em canídeos silvestres Indirect ELISA for the serological diagnosis of visceral leishmaniasis in wild canids

    Directory of Open Access Journals (Sweden)

    Paulo R.B. Ferreira

    2013-04-01

    Full Text Available Na América do Sul, alguns canídeos silvestres são considerados reservatórios naturais da Leishmania chagasi. A resposta imunológica desses animais à Leishmania é pouco conhecida, havendo a necessidade de métodos diagnósticos adequados para esse fim. No presente estudo, é descrita a padronização do ensaio imunoenzimático indireto (ELISA para o diagnóstico sorológico de leishmaniose visceral em canídeos silvestres brasileiros. Foram estudadas amostras de soro e plasma de 12 canídeos cativos: sete lobos-guará (Chrysocyon brachyurus, três raposinhas (Lycalopex vetulus e dois cachorros-do-mato (Cerdocyon thous. As amostras de um C. brachyurus e uma L. vetulus, cativos em área endêmica para LV, que apresentavam doença clínica e positividade em testes de Imunofluorescência Indireta e Reação em Cadeia de Polimerase, foram utilizadas como controles positivos. Foram comparados os conjugados anti-IgG de cão e proteína A, ambos ligados a peroxidase, cujos testes detectaram quatro (04/12 e três (03/12 C. brachyurus soropositivos para anticorpos anti-Leishmania sp., respectivamente. As médias das densidades ópticas (DOs das amostras negativas foram nitidamente mais baixas do que as médias das DOs dos positivos tanto no ELISA com anti-IgG de cão (4,8 vezes como com proteína A (15,5 vezes. Os soros de três C. brachyurus positivos no ELISA indireto foram avaliados por Western blotting e identificaram 22 bandas, sendo imunodominantes as de peso molecular de 19, 22, 24, 45 e 66 kDa. Os testes ELISA com a proteína A e o conjugado anti-IgG de cão apresentaram respectivamente concordância excelente (Kappa = 1; pIn South America, some wild canids are considered natural reservoirs of Leishmania chagasi. The immunological response of wild canids to Leishmania is not well understood, and the development of diagnostic methods is necessary for such purpose. In the present study, the standardization of an enzyme-linked immunosorbent

  5. Absorption lines of High Redshift GRB 130606A observed by Subaru FOCAS

    Science.gov (United States)

    Kurita, Shin; Kawai, Nobuyuki; Saito, Yoshihiko; Aoki, Kentaro; Kosugi, George; Hattori, Takashi; Totani, Tomonori

    We observed the optical afterglow of a Swift GRB 130606A using Subaru FOCAS. GRB 130606A has a redshift 5.91, the 5th highest redshift among the GRBs observed so far. The observation started 10.3 hours after the burst for 13.3 hours. We obtained the optical spectrum with a high S/N and detected ~40 absorption lines. Especially, absorption lines which have large equivalent widths shows their velocity. In some lines with high statistics, we study their velocity structures.

  6. SU(2)$_{\\tiny\\mbox{CMB}}$ at high redshifts and the value of $H_0$

    CERN Document Server

    Hahn, Steffen

    2016-01-01

    We investigate a high-$z$ cosmological model to compute the co-moving sound horizon $r_s$ at baryon freeze-out following hydrogen recombination. This model assumes a replacement of the conventional CMB photon gas by SU(2) Yang-Mills thermodynamics, three flavors of massless neutrinos ($N_\

  7. SU(2)CMB at high redshifts and the value of H0

    Science.gov (United States)

    Hahn, Steffen; Hofmann, Ralf

    2017-07-01

    We investigate a high-z cosmological model to compute the comoving sound horizon rs at baryon-velocity freeze-out towards the end of hydrogen recombination. This model assumes a replacement of the conventional cosmic microwave background (CMB) photon gas by deconfining SU(2) Yang-Mills thermodynamics, three flavours of massless neutrinos (Nν = 3) and a purely baryonic matter sector [no cold dark-matter (CDM)]. The according SU(2) temperature-redshift relation of the CMB is contrasted with recent measurements appealing to the thermal Sunyaev-Zel'dovich effect and CMB-photon absorption by molecular rotation bands or atomic hyperfine levels. Relying on a realistic simulation of the ionization history throughout recombination, we obtain z* = 1693.55 ± 6.98 and zdrag = 1812.66 ± 7.01. Due to considerable widths of the visibility functions in the solutions to the associated Boltzmann hierarchy and Euler equation, we conclude that z* and zdrag overestimate the redshifts for the respective photon and baryon-velocity freeze-out. Realistic decoupling values turn out to be zlf,* = 1554.89 ± 5.18 and zlf, drag = 1659.30 ± 5.48. With rs(zlf, drag) = (137.19 ± 0.45) Mpc and the essentially model independent extraction of rsH0 = constant from low-z data in Bernal, Verde & Riess, we obtain a good match with the value H0 = (73.24 ± 1.74) km s-1 Mpc-1 extracted in Riess et al. by appealing to Cepheid-calibrated Type Ia supernovae, new parallax measurements, stronger constraints on the Hubble flow and a refined computation of distance to NGC 4258 from maser data. We briefly comment on a possible interpolation of our high-z model, invoking percolated and unpercolated U(1) topological solitons of a Planck-scale axion field, to the phenomenologically successful low-z ΛCDM cosmology.

  8. Efficient adiabatic hydrodynamical simulations of the high-redshift intergalactic medium

    Science.gov (United States)

    Gaikwad, Prakash; Choudhury, Tirthankar Roy; Srianand, Raghunathan; Khaire, Vikram

    2018-02-01

    We present a post-processing tool for GADGET-2 adiabatic simulations to model various observed properties of the Ly α forest at 2.5 ≤ z ≤ 4 that enables an efficient parameter estimation. In particular, we model the thermal and ionization histories that are not computed self-consistently by default in GADGET-2. We capture the effect of pressure smoothing by running GADGET-2 at an elevated temperature floor and using an appropriate smoothing kernel. We validate our procedure by comparing different statistics derived from our method with those derived using self-consistent simulations with GADGET-3. These statistics are: line-of-sight density field power spectrum, flux probability distribution function, flux power spectrum, wavelet statistics, curvature statistics, H I column density (N_{H I}) distribution function, linewidth (b) distribution and b versus log N_{H I} scatter. For the temperature floor of 104 K and typical signal-to-noise ratio of 25, the results agree well within 20 per cent of the self-consistent GADGET-3 simulation. However, this difference is smaller than the expected 1σ sample variance for an absorption path length of ˜5.35 at z = 3. Moreover for a given cosmology, we gain a factor of ˜N in computing time for modelling the intergalactic medium under N ≫ 1 different thermal histories. In addition, our method allows us to simulate the non-equilibrium evolution of thermal and ionization state of the gas and include heating due to non-standard sources like cosmic rays and high-energy γ-rays from Blazars.

  9. PKS 2123-463: A Confirmed Gamma-ray Blazar at High Redshift

    Science.gov (United States)

    DAmmando, F.; Rau, A.; Schady, P.; Finke, J.; Orienti, M.; Greiner, J.; Kann, D. A.; Ojha, R.; Foley, A. R.; Stevens, J.; hide

    2012-01-01

    The flat spectrum radio quasar (FSRQ) PKS 2123-463 was associated in the First Fermi-LAT source catalog with the gamma-ray source 1FGL J2126.1-4603, but when considering the full first two years of Fermi observations, no gamma-ray source at a position consistent with this FSRQ was detected, and thus PKS 2123-463 was not reported in the Second Fermi-LAT source catalog. On 2011 December 14 a gamma-ray source positionally consistent with PKS 2123-463 was detected in flaring activity by Fermi-LAT. This activity triggered radio-to-X-ray observations by the Swift, GROND, ATCA, Ceduna, and KAT-7 observatories. Results of the localization of the gamma-ray source over 41 months of Fermi-LAT operation are reported here in conjunction with the results of the analysis of radio, optical, UV and X-ray data collected soon after the gamma-ray flare. The strict spatial association with the lower energy counterpart together with a simultaneous increase of the activity in optical, UV, X-ray and gamma-ray bands led to a firm identification of the gamma-ray source with PKS 2123-463. A new photometric redshift has been estimated as z = 1.46 +/- 0.05 using GROND and Swift/UVOT observations, in rough agreement with the disputed spectroscopic redshift of z = 1.67. We fit the broadband spectral energy distribution with a synchrotron/external Compton model. We find that a thermal disk component is necessary to explain the optical/UV emis- sion detected by Swift/UVOT. This disk has a luminosity of 1.8x1046 erg s-1, and a fit to the disk emission assuming a Schwarzschild (i.e., nonrotating) black hole gives a mass of 2 x 109 M(solar mass). This is the first black hole mass estimate for this source.

  10. VizieR Online Data Catalog: SCUBA-2 high-redshift galaxies sample (Barger+, 2014)

    Science.gov (United States)

    Barger, A. J.; Cowie, L. L.; Chen, C.-C.; Owen, F. N.; Wang, W.-H.; Casey, C. M.; Lee, N.; Sanders, D. B.; Williams, J. P.

    2017-05-01

    We obtained 25.4 hr of observations on the CDF-N with SCUBA-2 on the JCMT during observing runs in 2012 and 2013. The data were obtained using a mixture of scanning modes and under a variety of weather conditions. Using the CV Daisy scanning mode (detailed information about the SCUBA-2 scan patterns can be found in Holland et al. 2013MNRAS.430.2513H), we obtained a 2.2 hr observation in band 1 weather (225 GHz opacity<0.05) and a 16.5 hr observation in band 2 weather (225 GHz opacity ~0.05-0.08). We also obtained a 6.7 hr observation in band 2 weather using the pong-900 scanning mode. While SCUBA-2 observes at both 450 um and 850 um simultaneously, there are too few sources directly detected at 450 um in our data to be interesting. Thus, we only use the 850 um data in our subsequent analysis. (1 data file).

  11. How Environment Affects Star Formation: Tracing Activity in High Redshift Galaxy Clusters

    Science.gov (United States)

    Alberts, Stacey; Pope, A.; Brodwin, M.; Atlee, D. W.; Lin, Y.; Chary, R.; Dey, A.; Eisenhardt, P. R.; Gettings, D.; Gonzalez, A. H.; Jannuzi, B.; Mancone, C.; Moustakas, J.; Snyder, G. F.; Stanford, S. A.; Stern, D.; Weiner, B. J.; Zeimann, G.

    2014-01-01

    The emerging picture of the evolution of cluster galaxies indicates that the epoch of z>1 is a crucial period of active star formation and mass assembly in clusters. In this dissertation, I leverage a uniformly-selected cluster sample from the IRAC Shallow Cluster Survey (ISCS) with Herschel imaging to analyse the star formation (SF) activity in cluster galaxies over the past ten billion years. This analysis is two-fold: 1) using 274 clusters across the 9 square degree Bootes field, I perform a stacking analysis of mass-limited samples of cluster and field galaxies using wide-field Herschel observations over a long redshift baseline, z=0.3-1.5. I find that the average SF activity in cluster galaxies is evolving faster than in the field, with field-like SF in the cluster cores and enhanced SF activity in the cluster outskirts at z>1.2. By further breaking down my analysis by galaxy mass and type, I determine which mechanisms are capable of driving this evolution. 2) I use unique, deep Herschel imaging of 11 spectroscopically-confirmed clusters from z=1.1-1.8 to study the properties of individual infrared bright cluster galaxies as a function of redshift and cluster-centric radius. Combined with ancillary data, I determine the star formation, dust, and AGN properties of the most active cluster galaxies and tie the evolution of these properties back to the environment by comparing to field populations. By combining these two approaches, I constrain cluster galaxy properties during a pivotal epoch of dust-obscured star formation activity and mass assembly in some of the most extreme structures in the Universe.

  12. A study of high-redshift AGN feedback in SZ cluster samples

    Science.gov (United States)

    Bîrzan, L.; Rafferty, D. A.; Brüggen, M.; Intema, H. T.

    2017-10-01

    We present a study of active galactic nucleus (AGN) feedback at higher redshifts (0.3 HERGs) in massive clusters at z > 0.6, implying a transition from HERG-mode accretion to lower power low-excitation radio galaxy (LERG)-mode accretion at intermediate redshifts. Additionally, we use local radio-to-jet power scaling relations to estimate feedback power and find that half of the CF systems in our sample probably have enough heating to balance cooling. However, we postulate that the local relations are likely not well suited to predict feedback power in high-luminosity HERGs, as they are derived from samples composed mainly of lower luminosity LERGs.

  13. Pieces to the puzzle of high-redshift galaxies falling into place

    DEFF Research Database (Denmark)

    Geier, Stefan Johannes

    mass models. Our findings indicate older ages for these galaxies than expected. Also, their remarkable compactness was corroborated. Further conclusions such as about the validity of the downsizing paradigm are not possible given the very small sample of just two such galaxies. Furthermore, we present...

  14. CLUES to the past: Local Group progenitors amongst high-redshift Lyman break galaxies

    Science.gov (United States)

    Dayal, Pratika; Libeskind, Noam I.; Dunlop, James S.

    2013-06-01

    We use state-of-the-art numerical simulations to explore the observability and the expected physical properties of the progenitors of the Local Group galaxies at z ≃ 6-8, within 1 billion years of the big bang. We find that the most massive progenitors of the Milky Way (MW) and Andromeda (M31) at z ≃ 6 and 7 are predicted to have absolute ultraviolet (UV) continuum magnitudes MUV ≃ -17 to -18, suggesting that their analogues lie close to the detection limits of the deepest near-infrared (IR) surveys conducted to date [i.e. Hubble Space Telescope Wide Field Camera 3/IR Ultra Deep Field (UDF)12]. This in turn confirms that the majority of currently known z ≃ 6-8 galaxies are expected to be the seeds of present-day galaxies which are more massive than L* spirals. We also discuss the properties of the Local Group progenitors at these early epochs, extending down to absolute magnitudes MUV ≃ -13. The most massive MW/M31 progenitors at z ≃ 7 have stellar masses M* ≃ 107.5-8 M⊙, stellar metallicities Z* ˜ 3-6 per cent Z⊙, and predicted observed UV continuum slopes β ≃ -2.4 to -2.5.

  15. Simulating the detection and classification of high-redshift supernovae with HARMONI on the ELT

    Science.gov (United States)

    Bounissou, S.; Thatte, N.; Zieleniewski, S.; Houghton, R. C. W.; Tecza, M.; Hook, I.; Neichel, B.; Fusco, T.

    2018-02-01

    We present detailed simulations of integral field spectroscopic observations of a supernova in a host galaxy at z ˜ 3, as observed by the HARMONI spectrograph on the Extremely Large Telescope, asssisted by laser tomographic adaptive optics. The goal of the simulations, using the HSIM simulation tool, is to determine whether HARMONI can discern the supernova Type from spectral features in the supernova spectrum. We find that in a 3 hour observation, covering the near-infrared H and K bands, at a spectral resolving power of ˜3000, and using the 20×20 mas spaxel scale, we can classify supernova Type Ia and their redshift robustly up to 80 days past maximum light (20 days in the supernova rest frame). We show that HARMONI will provide spectra at z ˜ 3 that are of comparable (or better) quality to the best spectra we can currently obtain at z ˜ 1, thus allowing studies of cosmic expansion rates to be pushed to substantially higher redshifts.

  16. PROBING HIGH-REDSHIFT GALAXY FORMATION AT THE HIGHEST LUMINOSITIES: NEW INSIGHTS FROM DEIMOS SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung-Soo [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Dey, Arjun [National Optical Astronomy Observatory, Tucson, AZ 85726 (United States); Cooper, Michael C. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Reddy, Naveen [Department of Physics and Astronomy, University of California, Riverside, 900 University Avenue, Riverside, CA 92521 (United States); Jannuzi, Buell T. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2013-07-01

    We present Keck DEIMOS spectroscopic observations of the most UV-luminous star-forming galaxies at redshifts 3.2 < z < 4.6. Our sample, selected in the Booetes field of the NOAO Deep Wide-Field Survey, contains galaxies with luminosities of L* {approx}< L{sub UV} {approx}< 7 L* and is one of the largest samples to date of the most UV-luminous galaxies at these redshifts. Our spectroscopic data confirm 41 candidates as star-forming galaxies at 3.2 < z < 4.6 and validate the relatively clean selection of the photometric candidates with a contamination rate of 11%-28%. We find that the fraction of Ly{alpha} emitting galaxies increases with decreasing UV luminosity. None of the 12 galaxies with M{sub UV} < -22 (i.e., L{sub UV} > 3 L*) exhibit strong Ly{alpha} emission. We find strong evidence of large-scale outflows, transporting the neutral/ionized gas in the interstellar medium away from the galaxy. Galaxies exhibiting both interstellar absorption and Ly{alpha} emission lines show a significant offset between the two features, with a relative velocity of 200-1150 km s{sup -1}. We find tentative evidence that this measure of the outflow velocity increases with UV luminosity and/or stellar mass. The luminosity- and mass-dependent outflow strengths suggest that the efficiency of feedback and enrichment of the surrounding medium depend on these galaxy parameters. We also stack the individual spectra to construct composite spectra of the absorption-line-only and Ly{alpha}-emitting subsets of the UV luminous galaxies at z {approx_equal} 3.7. The composite spectra are very similar to those of lower-redshift and lower-luminosity Lyman break galaxy (LBG) samples, but with some subtle differences. Analyses of the composite spectra suggest that the UV luminous LBGs at z {approx_equal} 3.7 may have a higher covering fraction of absorbing gas, and may be older (or have had more prolonged star formation histories) than their lower-redshift and lower-luminosity counterparts. In addition, we have discovered that five galaxies in the sample belong to a massive overdensity at z = 3.78. Finally, two galaxies each show two distinct sets of interstellar absorption features. The latter may be a sign of a final stage of major merger, or clumpy disk formation. These systems are not expected in our sample: their presence implies that the frequency of such sources among our luminous z {approx_equal} 3.7 LBGs may be an order of magnitude higher than in lower-redshift and lower-luminosity samples.

  17. Gamma-ray bursts from stellar remnants - Probing the universe at high redshift

    NARCIS (Netherlands)

    Wijers, R.A.M.J.; Bloom, J.S.; Bagla, J.S.; Natarajan, P.

    1998-01-01

    A gamma-ray burst (GRB) releases an amount of energy similar to that of a supernova explosion, which combined with its rapid variability suggests an origin related to neutron stars or black holes. Since these compact stellar remnants form from the most massive stars not long after their birth, GRBs

  18. Star formation at high redshift and the importance of dust obscuration

    DEFF Research Database (Denmark)

    Michalowski, Michal

    observing program targeting these galaxies at the radio wavelengths. The obtained data are analysed simultaneously together with the literature data by means of spectral energy distribution (SED) modelling. I use the radiative transfer code called GRASIL, which calculates the entire UV-to-radio SED...... by dust obscuration. My analysis is based on two samples of galaxies,which have been confirmed to be associated with recent star formation, namely gamma-ray burst (GRB) host galaxies and submillimeterselected galaxies (SMGs). For GRB hosts the long-wavelength data are scarce, so I have started a large...

  19. A break in the high-redshift stellar mass Tully-Fisher relation

    Science.gov (United States)

    Christensen, Lise; Hjorth, Jens

    2017-09-01

    We investigate the stellar-mass Tully-Fisher relation (TFR) between the stellar mass and the integrated gas velocity dispersion, quantified by the kinematic estimator S0.5 measured from strong emission lines in spectra of galaxies at 0 law slope and normalization of the TFR are independent of redshift out to z ∼ 3. The scatter in the TFR is 3, the scatter increases and the existence of a correlation is not obvious. The high-luminosity sample exhibits a flatter slope of 1.5 ± 0.2 at z natural consequence of galaxy models with a mass-dependent stellar-to-halo mass ratio.

  20. How Accurately Can We Measure Galaxy Environment at High Redshift Using Only Photometric Redshifts?

    Science.gov (United States)

    Florez, Jonathan; Jogee, Shardha; Sherman, Sydney; Papovich, Casey J.; Finkelstein, Steven L.; Stevans, Matthew L.; Kawinwanichakij, Lalitwadee; Ciardullo, Robin; Gronwall, Caryl; SHELA/HETDEX

    2017-06-01

    We use a powerful synergy of six deep photometric surveys (Herschel SPIRE, Spitzer IRAC, NEWFIRM K-band, DECam ugriz, and XMM X-ray) and a future optical spectroscopic survey (HETDEX) in the Stripe 82 field to study galaxy evolution during the 1.9 environment using only our photometric redshifts. We compare both local and large-scale measures of environment (e.g., projected two-point correlation function, projected nearest neighbor densities, and galaxy counts within some projected aperture) at different photometric redshifts to cosmological simulations in order to quantify the uncertainty in our estimates of environment. We also explore how robustly one can recover the variation of galaxy properties with environment, when using only photometric redshifts. In the era of large photometric surveys, this work has broad implications for studies addressing the impact of environment on galaxy evolution at early cosmic epochs. We acknowledge support from NSF grants AST-1614798, AST-1413652 and NSF GRFP grant DGE-1610403.

  1. Planck intermediate results: XXXIX. The Planck list of high-redshift source candidates

    National Research Council Canada - National Science Library

    ...; Ade, P. A. R; Aghanim, N; Arnaud, M; Aumont, J; Baccigalupi, C; Banday, A. J; Barreiro, R. B; Bartolo, N; Battaner, E; Benabed, K; Benoit-Lévy, A; Bernard, J.-P; Bersanelli, M; Bielewicz, P; Bonaldi, A; Bonavera, L; Bond, J. R; Borrill, J; Bouchet, F. R; Boulanger, F; Burigana, C; Butler, R. C; Calabrese, E; Catalano, A; Chiang, H. C; Christensen, P. R; Clements, D. L; Colombo, L. P. L; Couchot, F; Coulais, A; Crill, B. P; Curto, A; Cuttaia, F; Danese, L; Davies, R. D; Davis, R. J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Dickinson, C; Diego, J. M; Dole, H; Doré, O; Douspis, M; Ducout, A; Dupac, X; Elsner, F; Enßlin, T. A; Eriksen, H. K; Falgarone, E; Finelli, F; Flores-Cacho, I; Frailis, M; Fraisse, A. A; Franceschi, E; Galeotta, S; Galli, S; Ganga, K; Giard, M; Giraud-Héraud, Y; Gjerløw, E; González-Nuevo, J; Górski, K. M; Gregorio, A; Gruppuso, A; Gudmundsson, J. E; Hansen, F. K; Harrison, D. L; Helou, G; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S. R; Hivon, E; Hobson, M; Hornstrup, A; Hovest, W; Huffenberger, K. M; Hurier, G; Jaffe, A. H; Jaffe, T. R; Keihänen, E; Keskitalo, R; Kisner, T. S; Kneissl, R; Knoche, J; Kunz, M; Kurki-Suonio, H; Lagache, G; Lamarre, J.-M; Lasenby, A; Lattanzi, M; Lawrence, C. R; Leonardi, R; Levrier, F; Liguori, M; Lilje, P. B; Linden-Vørnle, M; López-Caniego, M; Lubin, P. M

    2016-01-01

    The Planck mission, thanks to its large frequency range and all-sky coverage, has a unique potential for systematically detecting the brightest, and rarest, submillimetre sources on the sky, including...

  2. Large turbulent reservoirs of cold molecular gas around high-redshift starburst galaxies

    Science.gov (United States)

    Falgarone, E.; Zwaan, M. A.; Godard, B.; Bergin, E.; Ivison, R. J.; Andreani, P. M.; Bournaud, F.; Bussmann, R. S.; Elbaz, D.; Omont, A.; Oteo, I.; Walter, F.

    2017-08-01

    Starburst galaxies at the peak of cosmic star formation are among the most extreme star-forming engines in the Universe, producing stars over about 100 million years (ref. 2). The star-formation rates of these galaxies, which exceed 100 solar masses per year, require large reservoirs of cold molecular gas to be delivered to their cores, despite strong feedback from stars or active galactic nuclei. Consequently, starburst galaxies are ideal for studying the interplay between this feedback and the growth of a galaxy. The methylidyne cation, CH+, is a most useful molecule for such studies because it cannot form in cold gas without suprathermal energy input, so its presence indicates dissipation of mechanical energy or strong ultraviolet irradiation. Here we report the detection of CH+ (J = 1-0) emission and absorption lines in the spectra of six lensed starburst galaxies at redshifts near 2.5. This line has such a high critical density for excitation that it is emitted only in very dense gas, and is absorbed in low-density gas. We find that the CH+ emission lines, which are broader than 1,000 kilometres per second, originate in dense shock waves powered by hot galactic winds. The CH+ absorption lines reveal highly turbulent reservoirs of cool (about 100 kelvin), low-density gas, extending far (more than 10 kiloparsecs) outside the starburst galaxies (which have radii of less than 1 kiloparsec). We show that the galactic winds sustain turbulence in the 10-kiloparsec-scale environments of the galaxies, processing these environments into multiphase, gravitationally bound reservoirs. However, the mass outflow rates are found to be insufficient to balance the star-formation rates. Another mass input is therefore required for these reservoirs, which could be provided by ongoing mergers or cold-stream accretion. Our results suggest that galactic feedback, coupled jointly to turbulence and gravity, extends the starburst phase of a galaxy instead of quenching it.

  3. TRACING THE EVOLUTION OF HIGH-REDSHIFT GALAXIES USING STELLAR ABUNDANCES

    Energy Technology Data Exchange (ETDEWEB)

    Crosby, Brian D.; O’Shea, Brian W. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Beers, Timothy C. [Department of Physics and JINA—Center for the Evolution of the Elements, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Tumlinson, Jason, E-mail: crosby.bd@gmail.com [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2016-03-20

    This paper presents the first results from a model for chemical evolution that can be applied to N-body cosmological simulations and quantitatively compared to measured stellar abundances from large astronomical surveys. This model convolves the chemical yield sets from a range of stellar nucleosynthesis calculations (including asymptotic giant branch stars, Type Ia and II supernovae, and stellar wind models) with a user-specified stellar initial mass function (IMF) and metallicity to calculate the time-dependent chemical evolution model for a “simple stellar population” (SSP) of uniform metallicity and formation time. These SSP models are combined with a semianalytic model for galaxy formation and evolution that uses merger trees from N-body cosmological simulations to track several α- and iron-peak elements for the stellar and multiphase interstellar medium components of several thousand galaxies in the early (z ≥ 6) universe. The simulated galaxy population is then quantitatively compared to two complementary data sets of abundances in the Milky Way stellar halo and is capable of reproducing many of the observed abundance trends. The observed abundance ratio distributions are best reproduced with a Chabrier IMF, a chemically enriched star formation efficiency of 0.2, and a redshift of reionization of 7. Many abundances are qualitatively well matched by our model, but our model consistently overpredicts the carbon-enhanced fraction of stars at low metallicities, likely owing to incomplete coverage of Population III stellar yields and supernova models and the lack of dust as a component of our model.

  4. High-Redshift Radio Galaxies from Deep Fields C. H. Ishwara ...

    Indian Academy of Sciences (India)

    2International Centre for Radio Astronomical Research, University of Western Australia,. Perth, Western Australia, Australia. ∗ e-mail: ishwar@ncra.tifr.res.in. Abstract. Most of the radio ... cating that the known HzRGs represent the tip of the ice-berg in luminosity. There are, potentially, a large number of HzRGs yet to be ...

  5. γ-Rays Radiation of High Redshift Fermi Blazars WG Liu1, SH Fu2 ...

    Indian Academy of Sciences (India)

    significant positive correlation between Fγ and FR, and a weak anticorre- lation between Fγ and FK in the average ... Studies of the samples are crucial for learning more evolution sequences of the jet (Ghisellini et al. 2013). ... the multiwavelenght flux densities, we can learn the origin of γ-ray emissions and their generation ...

  6. Submillimetre observations of WISE-selected high-redshift, luminous AGN and their surrounding overdense environments

    Science.gov (United States)

    Jones, Suzy F.

    2016-08-01

    We present JCMT SCUBA-2 850 μm submillimetre (submm) observations of 10 mid-infrared (mid-IR) luminous active galactic nuclei (AGNs), detected by the Wide-field Infrared Survey Explorer (WISE) all-sky IR survey and 30 that have also been detected by the NVSS/FIRST radio survey. These rare sources are selected by their extremely red mid-IR spectral energy distributions (SEDs). Further investigations show that they are highly obscured, have abundant warm AGN-heated dust and are thought to be experiencing intense AGN feedback. When comparing the number of submm galaxies detected serendipitously in the surrounding 1.5 arcmin to those in blank-field submm surveys, there is a very significant overdensity, of order 3-5, but no sign of radial clustering centred at our primary objects. The WISE-selected AGN thus reside in 10-Mpc-scale overdense environments that could be forming in pre-viralized clusters of galaxies. WISE-selected AGNs appear to be the strongest signposts of high-density regions of active, luminous and dusty galaxies. SCUBA-2 850 μm observations indicate that their submm fluxes are low compared to many popular AGN SED templates, hence the WISE/radio-selected AGNs have either less cold and/or more warm dust emission than normally assumed for typical AGN. Most of the targets have total IR luminosities ≥1013 L⊙, with known redshifts of 20 targets between z ˜ 0.44-4.6.

  7. COSMIC REIONIZATION ON COMPUTERS. ULTRAVIOLET CONTINUUM SLOPES AND DUST OPACITIES IN HIGH REDSHIFT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Khakhaleva-Li, Zimu [Department of Physics, The University of Chicago, Chicago, IL 60637 (United States); Gnedin, Nickolay Y., E-mail: zimu@uchicago.edu, E-mail: gnedin@fnal.gov [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

    2016-04-01

    We compare the properties of stellar populations of model galaxies from the Cosmic Reionization On Computers (CROC) project with the exiting ultraviolet (UV) and IR data. Since CROC simulations do not follow cosmic dust directly, we adopt two variants of the dust-follows-metals ansatz to populate model galaxies with dust. Using the dust radiative transfer code Hyperion, we compute synthetic stellar spectra, UV continuum slopes, and IR fluxes for simulated galaxies. We find that the simulation results generally match observational measurements, but, perhaps, not in full detail. The differences seem to indicate that our adopted dust-follows-metals ansatzes are not fully sufficient. While the discrepancies with the exiting data are marginal, the future James Webb Space Telescope (JWST) data will be of much higher precision, rendering highly significant any tentative difference between theory and observations. It is, therefore, likely, that in order to fully utilize the precision of JWST observations, fully dynamical modeling of dust formation, evolution, and destruction may be required.

  8. The Hy-Redshift Universe: Galaxy Formation and Evolution at High Redshift

    Energy Technology Data Exchange (ETDEWEB)

    Bunker, A.J.; van Breugel, W.J.M.

    1999-11-03

    Hyron Spinrad's career has spanned several decades, and has stretched from our neighboring planets to the most remote galaxies in the Universe, pausing in between to ''enrich'' our knowledge of the compositions of stars.

  9. The intrinsic far-UV spectrum of the high-redshift quasar B1422+231

    Science.gov (United States)

    O'Dowd, M.; Bate, N. F.; Webster, R. L.; Labrie, K.; King, A. L.; Yong, S.-. Y.

    2018-02-01

    We present new spectroscopy of the z = 3.62 gravitationally lensed quasar B1422+117 from the Gemini North GMOS integral field spectrograph. We observe significant differential magnifications between the broad emission lines and the continuum, as well as across the velocity structure of the Lyman-α line. We take advantage of this differential microlensing to algebraically decompose the quasar spectrum into the absorbed broad emission line and absorbed continuum components. We use the latter to derive the intrinsic Ly α forest absorption spectrum. The proximity effect is clearly detected, with a proximity zone edge of 8.6-17.3 Mpc from the quasar, implying (perhaps intermittent) activity over at least 28 Myr. The Ly α line profile exhibits a blue excess that is inconsistent with a symmetric fit to the unabsorbed red side. This has important implications for the use of this fitting technique in estimating the absorbed blue Ly α wings of Gunn-Peterson trough quasars.

  10. High-redshift quasars host galaxies: is there a stellar mass crisis?

    NARCIS (Netherlands)

    Valiante, Rosa; Schneider, Raffaella; Salvadori, Stefania; Gallerani, Simona

    2014-01-01

    We investigate the evolutionary properties of a sample of quasars (QSOs) at 5

  11. Early Growth and Efficient Accretion of Massive Black Holes at High Redshift

    DEFF Research Database (Denmark)

    Vestergaard, Marianne

    2003-01-01

    and the lack of similarly large black-hole masses in the nearby Universe does not rule out their existence at high-z. However, AGN host galaxies do not typically appear fully formed or evolved at these early epochs. This supports scenarios in which black holes build up mass very fast in a radiatively...... inefficient (or obscured) phase relative to the stars in their galaxies. Additionally, upper envelopes of black-hole mass of approximately 10^{10} solar masses and bolometric luminosity of ~ 10^{48} erg/s are observed at all redshifts....

  12. The Bright and Dark Sides of High-redshift Starburst Galaxies from Herschel and Subaru Observations

    Energy Technology Data Exchange (ETDEWEB)

    Puglisi, A.; Rodighiero, G.; Rodríguez-Muñoz, L.; Mancini, C.; Franceschini, A. [Dipartimento di Fisica e Astronomia, Università di Padova, vicolo dell’Osservatorio 2, I-35122 Padova (Italy); Daddi, E.; Valentino, F.; Calabrò, A.; Jin, S. [Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service d’Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Renzini, A. [INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio, 5, I-35122 Padova (Italy); Silverman, J. D. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for for Advanced Study, The University of Tokyo, Kashiwanoha, Kashiwa 277-8583 (Japan); Kashino, D. [Institute for Astronomy, Department of Physics, ETH Zürich, Wolfgang-Pauli-strasse 27, CH-8093 Zürich (Switzerland); Mainieri, V.; Man, A. [ESO, Karl-Schwarschild-Straße 2, D-85748 Garching bei München (Germany); Darvish, B. [Cahill Center for Astrophysics, California Institute of Technology, 1216 East California Boulevard, Pasadena, CA 91125 (United States); Maier, C. [University of Vienna, Department of Astrophysics, Tuerkenschanzstrasse 17, A-1180 Vienna (Austria); Kartaltepe, J. S. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Sanders, D. B. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2017-04-01

    We present rest-frame optical spectra from the FMOS-COSMOS survey of 12 z ∼ 1.6 Herschel starburst galaxies, with star formation rate (SFR) elevated by ×8, on average, above the star-forming main sequence (MS). Comparing the H α to IR luminosity ratio and the Balmer decrement, we find that the optically thin regions of the sources contain on average only ∼10% of the total SFR, whereas ∼90% come from an extremely obscured component that is revealed only by far-IR observations and is optically thick even in H α . We measure the [N ii]{sub 6583}/H α ratio, suggesting that the less obscured regions have a metal content similar to that of the MS population at the same stellar masses and redshifts. However, our objects appear to be metal-rich outliers from the metallicity–SFR anticorrelation observed at fixed stellar mass for the MS population. The [S ii]{sub 6732}/[S ii]{sub 6717} ratio from the average spectrum indicates an electron density n {sub e} ∼ 1100 cm{sup −3} , larger than what was estimated for MS galaxies but only at the 1.5 σ level. Our results provide supporting evidence that high- z MS outliers are analogous of local ULIRGs and are consistent with a major-merger origin for the starburst event.

  13. Infrared-faint radio sources in the SERVS deep fields. Pinpointing AGNs at high redshift

    NARCIS (Netherlands)

    Maini, A.; Prandoni, I.; Norris, R. P.; Spitler, L. R.; Mignano, A.; Lacy, M.; Morganti, R.

    2016-01-01

    Context. Infrared-faint radio sources (IFRS) represent an unexpected class of objects which are relatively bright at radio wavelength, but unusually faint at infrared (IR) and optical wavelengths. A recent and extensive campaign on the radio-brightest IFRSs (S1.4 GHz≳ 10 mJy) has provided evidence

  14. Comparing Local Starbursts to High-Redshift Galaxies: A Search for Lyman-Break Analogs

    Science.gov (United States)

    Petty, Sara M.; de Mello, Duila F.; Gallagher III, John S.; Gardner, Jonathan; Lotz, Jennifer M.; Mountain, C. Matt; Smith, Linda J.

    2008-01-01

    We compare the restframe far-ultraviolet (FUV) morphologies of 8 nearby interacting and starburst galaxies (Arp 269, M 82, Mrk 08, NGC 0520, NGC 1068, NGC 3079, NGC 3310, NGC 7673) with 54 galaxies at z approx.1.5 and 46 galaxies at z approx.4 in the Great Observatories Origins Deep Survey (GOODS) images taken with the Advanced Camera for Surveys onboard the Hubble Space Telescope. We calculate the Gini coefficient (G), the second order moment of 20% of the brightest pixels (M20), and the S ersic index (n). We find that 20% (11/54) of z approx.1.5 and 37% (17/46) of z approx.4 galaxies are bulge-like, using G and M20. We also find approx.70% of the z approx.1.5 and z approx.4 galaxies have exponential disks with n > 0.8. The 2D profile combined with the nonparametric methods provides more detail, concerning the nature of disturbed systems, such as merger and post-merger types. We also provide qualitative descriptions of each galaxy system and at each redshift. We conclude that Mrk 08, NGC 3079, and NGC 7673 have similar morphologies as the starburst FUV restframe galaxies and Lyman-break galaxies at z approx.1.5 and 4, and determine that they are Lyman-break analogs.

  15. High-Redshift Galaxy Surveys and the Reionization of the Universe

    OpenAIRE

    Bouwens, Rychard J.

    2015-01-01

    Star-forming galaxies in the early universe provide us with perhaps the most natural way of explaining the reionization of the universe. Current observational results are sufficiently comprehensive, as to allow us to approximately calculate how the ionizing radiation from galaxies varies as a function of cosmic time. Important uncertainties in modeling reionization by galaxies revolve around the escape fraction and its luminosity and redshift dependence, a possible truncation of the galaxy lu...

  16. High-Redshift Galaxy Surveys and the Reionization of the Universe

    Science.gov (United States)

    Bouwens, Rychard

    Star-forming galaxies in the early universe provide us with perhaps the most natural way of explaining the reionization of the universe. Current observational results are sufficiently comprehensive, as to allow us to approximately calculate how the ionizing radiation from galaxies varies as a function of cosmic time. Important uncertainties in modeling reionization by galaxies revolve around the escape fraction and its luminosity and redshift dependence, a possible truncation of the galaxy luminosity function at the faint end, and an evolution in the production efficiency of Lyman-continuum photons with cosmic time. Despite these uncertainties, plausible choices for these parameters naturally predict a cosmic ionizing emissivity at z ˜ 6 - 10 z ˜ 6-10 whose evolution and overall normalization is in excellent agreement with that derived from current observational constraints. This strongly suggests that galaxies provide the necessary photons to reionize the universe.

  17. Constraints on dark matter scenarios from measurements of the galaxy luminosity function at high redshifts

    Science.gov (United States)

    Corasaniti, P. S.; Agarwal, S.; Marsh, D. J. E.; Das, S.

    2017-04-01

    We use state-of-the-art measurements of the galaxy luminosity function (LF) at z =6 , 7, and 8 to derive constraints on warm dark matter (WDM), late-forming dark matter, and ultralight axion dark matter models alternative to the cold dark matter (CDM) paradigm. To this purpose, we have run a suite of high-resolution N -body simulations to accurately characterize the low-mass end of the halo mass function and derive dark matter (DM) model predictions of the high-z luminosity function. In order to convert halo masses into UV magnitudes, we introduce an empirical approach based on halo abundance matching, which allows us to model the LF in terms of the amplitude and scatter of the ensemble average star formation rate halo mass relation, ⟨SFR (Mh ,z )⟩, of each DM model. We find that, independent of the DM scenario, the average SFR at fixed halo mass increases from z =6 to 8, while the scatter remains constant. At halo mass Mh≳1012 M⊙ h-1 , the average SFR as a function of halo mass follows a double power law trend that is common to all models, while differences occur at smaller masses. In particular, we find that models with a suppressed low-mass halo abundance exhibit higher SFR compared to the CDM results. Thus, different DM models predict a different faint-end slope of the LF which causes the goodness of fit to vary within each DM scenario for different model parameters. Using deviance statistics, we obtain a lower limit on the WDM thermal relic particle mass, mWDM≳1.5 keV at 2 σ . In the case of LFDM models, the phase transition redshift parameter is bounded to zt≳8 ×105 at 2 σ . We find ultralight axion dark matter best-fit models with axion mass ma≳1.6 ×10-22 eV to be well within 2 σ of the deviance statistics. We remark that measurements at z =6 slightly favor a flattening of the LF at faint UV magnitudes. This tends to prefer some of the non-CDM models in our simulation suite, although not at a statistically significant level to distinguish them from CDM.

  18. The Interstellar Medium in High-redshift Submillimeter Galaxies as Probed by Infrared Spectroscopy*

    Science.gov (United States)

    Wardlow, Julie L.; Cooray, Asantha; Osage, Willow; Bourne, Nathan; Clements, David; Dannerbauer, Helmut; Dunne, Loretta; Dye, Simon; Eales, Steve; Farrah, Duncan; Furlanetto, Cristina; Ibar, Edo; Ivison, Rob; Maddox, Steve; Michałowski, Michał M.; Riechers, Dominik; Rigopoulou, Dimitra; Scott, Douglas; Smith, Matthew W. L.; Wang, Lingyu; van der Werf, Paul; Valiante, Elisabetta; Valtchanov, Ivan; Verma, Aprajita

    2017-03-01

    Submillimeter galaxies (SMGs) at z≳ 1 are luminous in the far-infrared, and have star formation rates, SFR, of hundreds to thousands of solar masses per year. However, it is unclear whether they are true analogs of local ULIRGs or whether the mode of their star formation is more similar to that in local disk galaxies. We target these questions by using Herschel-PACS to examine the conditions in the interstellar medium (ISM) in far-infrared luminous SMGs at z˜ 1-4. We present 70-160 μm photometry and spectroscopy of the [O IV]26 μm, [Fe II]26 μm, [S III]33 μm, [Si II]34 μm, [O III]52 μm, [N III]57 μm, and [O I]63 μm fine-structure lines and the S(0) and S(1) hydrogen rotational lines in 13 lensed SMGs identified by their brightness in early Herschel data. Most of the 13 targets are not individually spectroscopically detected; we instead focus on stacking these spectra with observations of an additional 32 SMGs from the Herschel archive—representing a complete compilation of PACS spectroscopy of SMGs. We detect [O I]63 μm, [Si II]34 μm, and [N III]57 μm at ≥slant 3σ in the stacked spectra, determining that the average strengths of these lines relative to the far-IR continuum are (0.36+/- 0.12)× {10}-3, (0.84+/- 0.17)× {10}-3, and (0.27+/- 0.10)× {10}-3, respectively. Using the [O III]52 μm/[N III]57 μm emission line ratio, we show that SMGs have average gas-phase metallicities ≳ {Z}⊙ . By using PDR modeling and combining the new spectral measurements with integrated far-infrared fluxes and existing [C II]158 μm data, we show that SMGs have average gas densities, n, of ˜ {10}1-3 {{cm}}-3 and FUV field strengths, {G}0˜ {10}2.2-4.5 (in Habing units: 1.6× {10}-3 {erg} {{cm}}-2 {{{s}}}-1), consistent with both local ULIRGs and lower luminosity star-forming galaxies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia, and important participation from NASA.

  19. The Final SDSS High-redshift Quasar Sample of 52 Quasars at z>5.7

    Science.gov (United States)

    Jiang, Linhua; McGreer, Ian D.; Fan, Xiaohui; Strauss, Michael A.; Bañados, Eduardo; Becker, Robert H.; Bian, Fuyan; Farnsworth, Kara; Shen, Yue; Wang, Feige; Wang, Ran; Wang, Shu; White, Richard L.; Wu, Jin; Wu, Xue-Bing; Yang, Jinyi; Yang, Qian

    2016-12-01

    We present the discovery of nine quasars at z˜ 6 identified in the Sloan Digital Sky Survey (SDSS) imaging data. This completes our survey of z˜ 6 quasars in the SDSS footprint. Our final sample consists of 52 quasars at 5.7\\lt z≤slant 6.4, including 29 quasars with {z}{AB}≤slant 20 mag selected from 11,240 deg2 of the SDSS single-epoch imaging survey (the main survey), 10 quasars with 20≤slant {z}{AB}≤slant 20.5 selected from 4223 deg2 of the SDSS overlap regions (regions with two or more imaging scans), and 13 quasars down to {z}{AB}≈ 22 mag from the 277 deg2 in Stripe 82. They span a wide luminosity range of -29.0≤slant {M}1450≤slant -24.5. This well-defined sample is used to derive the quasar luminosity function (QLF) at z˜ 6. After combining our SDSS sample with two faint ({M}1450≥slant -23 mag) quasars from the literature, we obtain the parameters for a double power-law fit to the QLF. The bright-end slope β of the QLF is well constrained to be β =-2.8+/- 0.2. Due to the small number of low-luminosity quasars, the faint-end slope α and the characteristic magnitude {M}1450* are less well constrained, with α =-{1.90}-0.44+0.58 and {M}* =-{25.2}-3.8+1.2 mag. The spatial density of luminous quasars, parametrized as ρ ({M}1450\\lt -26,z)=ρ (z=6){10}k(z-6), drops rapidly from z˜ 5 to 6, with k=-0.72+/- 0.11. Based on our fitted QLF and assuming an intergalactic medium (IGM) clumping factor of C = 3, we find that the observed quasar population cannot provide enough photons to ionize the z˜ 6 IGM at ˜90% confidence. Quasars may still provide a significant fraction of the required photons, although much larger samples of faint quasars are needed for more stringent constraints on the quasar contribution to reionization.

  20. Deep Grism Spectroscopy of High Redshift Galaxies with the HST GRAPES and PEARS Surveys

    Science.gov (United States)

    Rhoads, James E.; Malhotra, S.; Pirzkal, N.; GRAPES Team; PEARS Team

    2011-01-01

    We have obtained the deepest slitless spectroscopic samples ever using the Hubble Space Telescope's Advanced Camera for Surveys, in two related projects, the "Grism ACS Program for Extragalactic Science" (GRAPES) and "Probing Evolution and Reionization Spectroscopically" (PEARS). In combination, these two programs obtained deep public spectroscopy of about 100 square arcminutes in the GOODS north and south fields. We are using these data to study galaxy evolution over a wide range of cosmic history. We are able to spectroscopically confirm Lyman break galaxies from redshift 4 to 6.5, down to AB magnitudes fainter than i=27.5. We use these samples to study a range of galaxy properties, including spatial clustering, Lyman alpha emitter fraction, and spatial extent of Lyman alpha emission.

  1. Local Group Dwarf Galaxies and the Star Formation Law at High Redshift.

    Science.gov (United States)

    Gnedin

    2000-06-01

    I show how the existing observational data on Local Group dwarf galaxies can be used to estimate the average star formation law during the first 3 Gyr of the history of the universe. I find that the observational data are consistent with the orthodox Schmidt law with a star formation efficiency of about 4% if the star formation is continuous (during the first 3 Gyr). The efficiency is proportionally higher if most of the gas in the dwarfs was consumed (and never replenished) in a short time interval well before the universe turned 3 Gyr.

  2. Pieces to the puzzle of high-redshift galaxies falling into place

    DEFF Research Database (Denmark)

    Geier, Stefan Johannes

    Our Universe is filled with a mind-blowing diversity and different types and appearances of galaxies. Finding out about how they formed and evolved is one of the most challenging tasks in astronomy. When looking about 10 billion years back, to an epoch about 3 billion years after the big bang, we...... can see galaxies at earlier stages of their lives. In this thesis studies of different kinds of galaxies in the early universe are presented. Two examples of the very intriguing population of massive quiescent z~2 galaxies were analyzed in terms of their stellar populations and morphologies. Although...... during the past decade big steps forward have been made in the study of this particular population of galaxies, key questions about their formation and evolution remain unsolved and the observational sample is still small, especially for galaxies at the faint end of the luminosity function. To make...

  3. High Redshift Radio Galaxies: Laboratories for Massive Galaxy and Cluster Formation in the Early Universe

    Science.gov (United States)

    2010-01-01

    description of the major emitting components which provide important diagnostics about various physical constituents of the early Universe. A list of known...HzRG building blocks is given in Table 1, together with a summary of techniques used to study them. Also included are a list of the resultant...detection of supernovae in z ∼ 2 protoclusters will become possible. On a longer timescale, tracing the detailed history of the formation and evolution of

  4. GTC optical imaging of extremely red 5C radio galaxies at high redshift

    Science.gov (United States)

    Humphrey, A.; Villar-Martín, M.; Lagos, P.

    2016-01-01

    Aims: We investigate the nature of seven unusual radio galaxies from the 5C catalogue that were previously known to have extremely red R-K colours, and for which emission lines were previously found to be weak or absent in their optical spectra. Methods: We present and discuss u, g, or r images of these radio galaxies, obtained using the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at the Gran Telescopio Canarias (GTC). Results: We have detected all seven targets in our g-band imaging. Their optical emission is extended, and we tentatively detect a radio-optical alignment effect in this sample. A subset of our sample (three sources) shows broad-band spectral energy distributions that flatten out near the wavelength range of the g-band, implying a dominant contribution there due to young stars and/or scattered or reprocessed radiation from the active nucleus.

  5. Examining High Redshift Rotation Curves and Dark Matter Profiles Outside the Local Universe

    Science.gov (United States)

    Cutler, Sam Edward

    2018-01-01

    Examination of galactic rotation curves in the local universe has yielded evidence of both cusp and core type dark matter profiles. We present one of the first studies of a galactic rotation curve for a distant gravitationally-lensed massive, dusty star-forming galaxy, CL2244-1, with a spectroscopic redshift 1.77. Using VLT/XSHOOTER spectroscopy, we perform a 2D spectral analysis of the H-alpha emission. With this rotation curve, we fit a dark matter density profile and determine the functional form of the profile (cusp or core). Predictions from comparing the shape of the rotation curve of CL2244-1 to that of M33 and other galaxies in the local universe suggest that the dark matter profile of CL2244-1 is best represented by a cuspy profile. Though this cuspy profile supports the cold dark matter cosmological model, we cannot rule out self-interacting dark matter, whose interactions may not have had time to shift the density profile to a core at such early times.

  6. Approaching reionization from two directions: high-redshift Lyman-alpha emitters and local analogs

    Science.gov (United States)

    Bagley, Micaela

    2018-01-01

    The dark ages that followed the recombination of the universe ended with the appearance of metal-free stars and the subsequent formation of numerous low-mass, metal-poor galaxies. The collective ionizing background from these newly-forming galaxies is thought to be responsible for the reionization of the diffuse hydrogen in the intergalactic medium between redshifts 10 and 6.5. The progression of the reionization history depends on the nature of these first sources -- their number densities, luminosities, clustering, and production rates of ionizing photons -- which is currently the subject of considerable observational and theoretical efforts.I will present results of a two-pronged approach to studying the Epoch of Reionization: a systematic search for Lyman-alpha emitting galaxies at redshifts greater than 6, and an analysis of high S/N spectra of a sample of local galaxies that are potential analogs to those responsible for the reionization. Selected for their large [OIII]/[OII] ratios and high H-alpha equivalent widths, the local galaxies have very low masses and are consistent with photoionization by stars with effective temperatures of 10^5 K. Both the emission lines and continua of the spectra are spatially extended, allowing for an analysis of galaxy properties such as gas temperature, elemental abundance, and ionizing power at different radii.

  7. Food habits of two syntopic canids, the maned wolf (Chrysocyon brachyurus and the crab-eating fox (Cerdocyon thous, in southeastern Brazil Hábitos alimentarios de dos cánidos sintópicos, el aguara guazú (Chrysocyon brachyurus y el zorro del monte (Cerdocyon thous, en el sudeste de Brasil

    Directory of Open Access Journals (Sweden)

    ADRIANA DE ARRUDA BUENO

    2004-03-01

    Full Text Available The maned wolf (Chrysocyon brachyurus and the crab-eating fox (Cerdocyon thous are two South American canids with large overlap in their geographic distribution. However, there are few data on the comparative ecology of these species. The aim of this research was to quantify the diet of these two canids living in syntopy at three levels: frequency of occurrence, minimum number of individuals preyed and estimated biomass ingested. Additionally, seasonality in the consumption of major groups of food items and aspects of prey size distribution were assessed. The study took place in the Experimental Station of Itapetininga, São Paulo State, Brazil. General results showed that both canids are omnivorous in accordance with other studies. By occurrences, the wolves consumed vegetal and animal food in similar proportions, whereas the foxes consumed more animals, mainly insects. In contrast, both canids ingested mainly animal food if biomass is considered. The maned wolf consumed more wolf's fruit (Solanum lycocarpum and small mammals in the dry season, and miscellaneous fruits during the wet season. The crab-eating fox also ingested more miscellaneous fruits in the wet season, but the insects were mostly consumed during dry months. The crab-eating fox is more generalist than the maned wolf, but the wolf seems better able to handle distinct prey types. The distribution of prey sizes suggested separate food niches: while the maned wolf consumed a larger spectrum of prey sizes, especially small vertebrates between 10.1 and 100.0 g, the crab-eating fox consumed smaller prey, mainly insects between 0.01 and 0.1 gEl aguara guazú (Chrysocyon brachyurus y el zorro del monte (Cerdocyon thous son dos cánidos sudamericanos cuyas distribuciones geográficas se sobreponen extensamente. Sin embargo, hay pocos datos sobre la ecología comparativa de estas especies. El objetivo de esta investigación fue cuantificar la dieta de estos dos cánidos en sintopia en

  8. Feedback From the First Supernovae in Protogalaxies:The Fate of the Generated Metals

    OpenAIRE

    Wada, K.; Venkatesan, A.

    2003-01-01

    We investigate the chemo-dynamical effects of multiple supernova explosions in the central region of primordial galaxies using three-dimensional hydrodynamical simulations of the inhomogenous interstellar medium down to parsec-scales. We find that the final protogalactic structure and metal distribution depend strongly on the number of SNe. Specifically, 1) 1000 SNe after an instantaneous burst of star formation are sufficient to almost completely blow away the gas in these systems, whereas 2...

  9. Parasites of domestic and wild canids in the region of Serra do Cipó National Park, Brazil Parasitos de canídeos domésticos e silvestres na região do Parque Nacional da Serra do Cipó - Brasil

    Directory of Open Access Journals (Sweden)

    Juliana Lúcia Costa Santos

    2012-09-01

    Full Text Available Over recent decades, diseases have been shown to be important causes of extinctions among wild species. Greater emphasis has been given to diseases transmitted by domestic animals, which have been increasing in numbers in natural areas, along with human populations. This study had the aim of investigating the presence of intestinal helminths in wild canids (maned wolf, Chrysocyon brachyurus, and crab-eating fox, Cerdocyon thous in the Serra do Cipó National Park (43-44º W and 19-20º S and endo and ectoparasites of domestic dogs in the Morro da Pedreira Environmental Protection Area (an area surrounding the National Park. The Serra do Cipó is located in the state of Minas Gerais, Brazil. Among the enteroparasites found in domestic and wild canids, the following taxons were identified: Ancylostomidae, Trichuridae, Toxocara sp., Spirocerca sp., Physaloptera sp., Strongyloides sp., Cestoda, Dipylidium caninum, Diphyllobothriidae, Hymenolepidae, Anoplocephalidae, Trematoda, Acanthocephala and Isospora sp. Domestic dogs were positive for leishmaniasis and Babesia canis in serological tests. Among the ectoparasites, Rhipicephalus sanguineus, Amblyomma cajennense and Ctenocephalides felis felis were observed in domestic dogs. Variations in the chaetotaxy of the meta-episternum and posterior tibia were observed in some specimens of C. felis felis.Nas últimas décadas, as doenças têm sido apontadas como importantes causas de extinção de espécies silvestres. Maior ênfase tem sido dada às doenças transmitidas por animais domésticos que crescem em número, bem como as populações humanas, em áreas naturais. O presente estudo objetivou verificar a presença de helmintos intestinais de canídeos silvestres (lobo-guará - Chrysocyon brachyurus e cachorro-do-mato - Cerdocyon thous do Parque Nacional da Serra do Cipó (43-44º W e 19-20º S e endo e ectoparasitos de cães domésticos da Área de Proteção Ambiental Morro da Pedreira (entorno do

  10. Canid hybridization: contemporary evolution in human-modified landscapes.

    Science.gov (United States)

    Stronen, Astrid V; Tessier, Nathalie; Jolicoeur, Hélène; Paquet, Paul C; Hénault, Michel; Villemure, Mario; Patterson, Brent R; Sallows, Tim; Goulet, Gloria; Lapointe, François-Joseph

    2012-09-01

    Contemporary evolution through human-induced hybridization occurs throughout the taxonomic range. Formerly allopatric species appear especially susceptible to hybridization. Consequently, hybridization is expected to be more common in regions with recent sympatry owing to human activity than in areas of historical range overlap. Coyotes (Canis latrans) and gray wolves (C. lupus) are historically sympatric in western North America. Following European settlement gray wolf range contracted, whereas coyote range expanded to include eastern North America. Furthermore, wolves with New World (NW) mitochondrial DNA (mtDNA) haplotypes now extend from Manitoba to Québec in Canada and hybridize with gray wolves and coyotes. Using mtDNA and 12 microsatellite markers, we evaluated levels of wolf-coyote hybridization in regions where coyotes were present (the Canadian Prairies, n = 109 samples) and absent historically (Québec, n = 154). Wolves with NW mtDNA extended from central Saskatchewan (51°N, 69°W) to northeastern Québec (54°N, 108°W). On the Prairies, 6.3% of coyotes and 9.2% of wolves had genetic profiles suggesting wolf-coyote hybridization. In contrast, 12.6% of coyotes and 37.4% of wolves in Québec had profiles indicating hybrid origin. Wolves with NW and Old World (C. lupus) mtDNA appear to form integrated populations in both regions. Our results suggest that hybridization is more frequent in historically allopatric populations. Range shifts, now expected across taxa following climate change and other human influence on the environment, might therefore promote contemporary evolution by hybridization.

  11. Admixture mapping identifies introgressed genomic regions in North American canids.

    Science.gov (United States)

    vonHoldt, Bridgett M; Kays, Roland; Pollinger, John P; Wayne, Robert K

    2016-06-01

    Hybrid zones typically contain novel gene combinations that can be tested by natural selection in a unique genetic context. Parental haplotypes that increase fitness can introgress beyond the hybrid zone, into the range of parental species. We used the Affymetrix canine SNP genotyping array to identify genomic regions tagged by multiple ancestry informative markers that are more frequent in an admixed population than expected. We surveyed a hybrid zone formed in the last 100 years as coyotes expanded their range into eastern North America. Concomitant with expansion, coyotes hybridized with wolves and some populations became more wolflike, such that coyotes in the northeast have the largest body size of any coyote population. Using a set of 3102 ancestry informative markers, we identified 60 differentially introgressed regions in 44 canines across this admixture zone. These regions are characterized by an excess of exogenous ancestry and, in northeastern coyotes, are enriched for genes affecting body size and skeletal proportions. Further, introgressed wolf-derived alleles have penetrated into Southern US coyote populations. Because no wolves currently exist in this area, these alleles are unlikely to have originated from recent hybridization. Instead, they probably originated from intraspecific gene flow or ancient admixture. We show that grey wolf and coyote admixture has far-reaching effects and, in addition to phenotypically transforming admixed populations, allows for the differential movement of alleles from different parental species to be tested in new genomic backgrounds. © 2016 John Wiley & Sons Ltd.

  12. Canid hybridization: contemporary evolution in human-modified landscapes

    Science.gov (United States)

    Stronen, Astrid V; Tessier, Nathalie; Jolicoeur, Hélène; Paquet, Paul C; Hénault, Michel; Villemure, Mario; Patterson, Brent R; Sallows, Tim; Goulet, Gloria; Lapointe, François-Joseph

    2012-01-01

    Contemporary evolution through human-induced hybridization occurs throughout the taxonomic range. Formerly allopatric species appear especially susceptible to hybridization. Consequently, hybridization is expected to be more common in regions with recent sympatry owing to human activity than in areas of historical range overlap. Coyotes (Canis latrans) and gray wolves (C. lupus) are historically sympatric in western North America. Following European settlement gray wolf range contracted, whereas coyote range expanded to include eastern North America. Furthermore, wolves with New World (NW) mitochondrial DNA (mtDNA) haplotypes now extend from Manitoba to Québec in Canada and hybridize with gray wolves and coyotes. Using mtDNA and 12 microsatellite markers, we evaluated levels of wolf-coyote hybridization in regions where coyotes were present (the Canadian Prairies, n = 109 samples) and absent historically (Québec, n = 154). Wolves with NW mtDNA extended from central Saskatchewan (51°N, 69°W) to northeastern Québec (54°N, 108°W). On the Prairies, 6.3% of coyotes and 9.2% of wolves had genetic profiles suggesting wolf-coyote hybridization. In contrast, 12.6% of coyotes and 37.4% of wolves in Québec had profiles indicating hybrid origin. Wolves with NW and Old World (C. lupus) mtDNA appear to form integrated populations in both regions. Our results suggest that hybridization is more frequent in historically allopatric populations. Range shifts, now expected across taxa following climate change and other human influence on the environment, might therefore promote contemporary evolution by hybridization. PMID:23139873

  13. Cystine nephrolithiasis in an endangered canid, Chrysocyon brachyurus (Carnivora: Canidae

    Directory of Open Access Journals (Sweden)

    Norma B. Mussart

    1999-09-01

    Full Text Available Se halló cálculos de cistina en la pelvis renal de un ejemplar adulto de Chrysocyon brachyurus (aguará-guazú, cuya muerte había ocurrido en el zoológico de Sáenz Peña (Chaco. El diagnóstico fue realizado por el método colorimétrico del nitroprusiato. La presencia de cristales microscópicos hexagonales en el cálculo pulverizado confirmó la presunción de cistina. La cistinuria es una aminoaciduria hereditaria que a largo plazo produce nefrolitiasis. El aguará-guazú puede padecer esta metabolopatía, por lo que durante su cautiverio la orina de este animal debería ser investigada para detectar la presencia de cristales de cistina; un tratamiento oportuno puede salvarle la vida. En Argentina, el número de C. brachyurus no superaría los 1000 ejemplares, en peligro de extinción.

  14. Acoustic signalling in a small, socially monogamous canid

    DEFF Research Database (Denmark)

    Darden, Safi-Kirstine; Dabelsteen, Torben

    2008-01-01

    territoriality and the function of long-ranging barking sequences in a wild population of swift foxes, Vulpes velox. We monitored space use and barking behaviour and combined this with experimental acoustic playback during the mating season. Mated male foxes used barking sequences mainly inside or close...... to be partly overlapped by neighbouring home ranges and therefore we cannot arbitrarily define 50% home range cores as territories. Still, pair home ranges had areas that were exclusive to the mated pair and their primary and secondary daytime sleeping dens were usually located inside these areas....... These results suggest that the barking sequence is used in territorial defence and we conclude that at least male swift foxes are territorial in the mating season and they use a long-ranging acoustic signal in territory defence....

  15. The MUSE Hubble Ultra Deep Field Survey. II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies

    Science.gov (United States)

    Inami, H.; Bacon, R.; Brinchmann, J.; Richard, J.; Contini, T.; Conseil, S.; Hamer, S.; Akhlaghi, M.; Bouché, N.; Clément, B.; Desprez, G.; Drake, A. B.; Hashimoto, T.; Leclercq, F.; Maseda, M.; Michel-Dansac, L.; Paalvast, M.; Tresse, L.; Ventou, E.; Kollatschny, W.; Boogaard, L. A.; Finley, H.; Marino, R. A.; Schaye, J.; Wisotzki, L.

    2017-11-01

    We have conducted a two-layered spectroscopic survey (1' × 1' ultra deep and 3' × 3' deep regions) in the Hubble Ultra Deep Field (HUDF) with the Multi Unit Spectroscopic Explorer (MUSE). The combination of a large field of view, high sensitivity, and wide wavelength coverage provides an order of magnitude improvement in spectroscopically confirmed redshifts in the HUDF; i.e., 1206 secure spectroscopic redshifts for Hubble Space Telescope (HST) continuum selected objects, which corresponds to 15% of the total (7904). The redshift distribution extends well beyond z> 3 and to HST/F775W magnitudes as faint as ≈ 30 mag (AB, 1σ). In addition, 132 secure redshifts were obtained for sources with no HST counterparts that were discovered in the MUSE data cubes by a blind search for emission-line features. In total, we present 1338 high quality redshifts, which is a factor of eight increase compared with the previously known spectroscopic redshifts in the same field. We assessed redshifts mainly with the spectral features [O II] at zhttp://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/608/A2

  16. The Hubble Space Telescope Cluster Supernova Survey. II. The Type Ia Supernova Rate in High-redshift Galaxy Clusters

    Science.gov (United States)

    Barbary, K.; Aldering, G.; Amanullah, R.; Brodwin, M.; Connolly, N.; Dawson, K. S.; Doi, M.; Eisenhardt, P.; Faccioli, L.; Fadeyev, V.; Fakhouri, H. K.; Fruchter, A. S.; Gilbank, D. G.; Gladders, M. D.; Goldhaber, G.; Goobar, A.; Hattori, T.; Hsiao, E.; Huang, X.; Ihara, Y.; Kashikawa, N.; Koester, B.; Konishi, K.; Kowalski, M.; Lidman, C.; Lubin, L.; Meyers, J.; Morokuma, T.; Oda, T.; Panagia, N.; Perlmutter, S.; Postman, M.; Ripoche, P.; Rosati, P.; Rubin, D.; Schlegel, D. J.; Spadafora, A. L.; Stanford, S. A.; Strovink, M.; Suzuki, N.; Takanashi, N.; Tokita, K.; Yasuda, N.; Supernova Cosmology Project

    2012-01-01

    We report a measurement of the Type Ia supernova (SN Ia) rate in galaxy clusters at 0.9 z z > 0.9 SNe. Finding 8 ± 1 cluster SNe Ia, we determine an SN Ia rate of 0.50+0.23 -0.19 (stat) +0.10 -0.09 (sys) h 2 70 SNuB (SNuB ≡ 10-12 SNe L -1 ⊙, B yr-1). In units of stellar mass, this translates to 0.36+0.16 -0.13 (stat) +0.07 -0.06 (sys) h 2 70 SNuM (SNuM ≡ 10-12 SNe M -1 ⊙ yr-1). This represents a factor of ≈5 ± 2 increase over measurements of the cluster rate at z influence of younger stellar populations by calculating the rate specifically in cluster red-sequence galaxies and in morphologically early-type galaxies, finding results similar to the full cluster rate. Finally, the upper limit of one hostless cluster SN Ia detected in the survey implies that the fraction of stars in the intra-cluster medium is less than 0.47 (95% confidence), consistent with measurements at lower redshifts. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Institute. STScI is operated by the association of Universities for Research in Astronomy, Inc., under the NASA contract NAS 5-26555. The observations are associated with program GO-10496.

  17. A New Determination of the High Redshift Type Ia Supernova Rateswith the Hubble Space Telescope Advanced Camera for Surveys

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsova, N.; Barbary, K.; Connolly, B.; Kim, A.G.; Pain, R.; Roe, N.A.; Aldering, G.; Amanullah, R.; Dawson, K.; Doi, M.; Fadeyev, V.; Fruchter, A.S.; Gibbons, R.; Goldhaber, G.; Goober, A.; Gude, A.; Knop,R.A.; Kowalski, M.; Lidman, C.; Morokuma, T.; Meyers, J.; Perlmutter, S.; Rubin, D.; Schlegel, D.J.; Spadafora, A.L.; Stanishev, V.; Strovink, M.; Suzuki, N.; Wang, L.; Yasuda, N.

    2007-10-01

    We present a new measurement of the volumetric rate of Type Ia supernova up to a redshift of 1.7, using the Hubble Space Telescope (HST) GOODS data combined with an additional HST dataset covering the North GOODS field collected in 2004. We employ a novel technique that does not require spectroscopic data for identifying Type Ia supernovae (although spectroscopic measurements of redshifts are used for over half the sample); instead we employ a Bayesian approach using only photometric data to calculate the probability that an object is a Type Ia supernova. This Bayesian technique can easily be modified to incorporate improved priors on supernova properties, and it is well-suited for future high-statistics supernovae searches in which spectroscopic follow up of all candidates will be impractical. Here, the method is validated on both ground- and space-based supernova data having some spectroscopic follow up. We combine our volumetric rate measurements with low redshift supernova data, and fit to a number of possible models for the evolution of the Type Ia supernova rate as a function of redshift. The data do not distinguish between a flat rate at redshift > 0.5 and a previously proposed model, in which the Type Ia rate peaks at redshift {approx} 1 due to a significant delay from star-formation to the supernova explosion. Except for the highest redshifts, where the signal to noise ratio is generally too low to apply this technique, this approach yields smaller or comparable uncertainties than previous work.

  18. The bispectrum of galaxies from high-redshift galaxy surveys: Primordial non-Gaussianity and non-linear galaxy bias

    Energy Technology Data Exchange (ETDEWEB)

    Sefusatti, Emiliano; /Fermilab; Komatsu, Eiichiro; /Texas U., Astron. Dept.

    2007-05-01

    The greatest challenge in the interpretation of galaxy clustering data from any surveys is galaxy bias. Using a simple Fisher matrix analysis, we show that the bispectrum provides an excellent determination of linear and non-linear bias parameters of intermediate and high-z galaxies, when all measurable triangle configurations down to mildly non-linear scales, where perturbation theory is still valid, are included. The bispectrum is also a powerful probe of primordial non-Gaussianity. The planned galaxy surveys at z {approx}> 2 should yield constraints on non-Gaussian parameters, f{sub NL}{sup loc.} and f{sub NL}{sup eq.}, that are comparable to, or even better than, those from CMB experiments. We study how these constraints improve with volume, redshift range, as well as the number density of galaxies. Finally we show that a halo occupation distribution may be used to improve these constraints further by lifting degeneracies between gravity, bias, and primordial non-Gaussianity.

  19. TESTING THE UNIVERSALITY OF THE FUNDAMENTAL METALLICITY RELATION AT HIGH REDSHIFT USING LOW-MASS GRAVITATIONALLY LENSED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Belli, Sirio; Ellis, Richard S. [Department of Astronomy, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Jones, Tucker [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Richard, Johan [Centre de Recherche Astrophysique de Lyon, Universite Lyon 1, 9 Avenue Charles Andre, F-69561 Saint Genis Laval Cedex (France)

    2013-08-01

    We present rest-frame optical spectra for a sample of nine low-mass star-forming galaxies in the redshift range 1.5 < z < 3 which are gravitationally lensed by foreground clusters. We used Triplespec, an echelle spectrograph at the Palomar 200 inch telescope that is very effective for this purpose as it samples the entire near-infrared spectrum simultaneously. By measuring the flux of nebular emission lines, we derive gas-phase metallicities and star formation rates, and by fitting the optical to infrared spectral energy distributions we obtain stellar masses. Taking advantage of the high magnification due to strong lensing, we are able to probe the physical properties of galaxies with stellar masses in the range 7.8 < log M/M{sub Sun} < 9.4 whose star formation rates are similar to those of typical star-forming galaxies in the local universe. We compare our results with the locally determined relation between stellar mass, gas metallicity, and star formation rate. Our data are in excellent agreement with this relation, with an average offset ({Delta}log (O/H)) = 0.01 {+-} 0.08, suggesting a universal relationship. Remarkably, the scatter around the fundamental metallicity relation is only 0.24 dex, smaller than that observed locally at the same stellar masses, which may provide an important additional constraint for galaxy evolution models.

  20. Mapping the Dark Matter From UV Light at High Redshift: An Empirical Approach to Understand Galaxy Statistics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung-Soo; /Yale Ctr. Astron. Astrophys.; Giavalisco, Mauro; /Massachusetts U., Amherst; Conroy, Charlie; /Princeton U. Observ.; Wechsler, Risa H; /KIPAC, Menlo Park; Ferguson, Henry C.; Somerville, Rachel S.; /Baltimore, Space Telescope Sci.; Dickinson, Mark E.; /NOAO, Tucson; Urry, Claudia M.; /Yale Ctr. Astron. Astrophys.

    2009-08-03

    We present a simple formalism to interpret the observations of two galaxy statistics, the UV luminosity function (LF) and two-point correlation functions for star-forming galaxies at z {approx} 4, 5 and 6 in the context of {Lambda}CDM cosmology. Both statistics are the result of how star formation takes place in dark matter halos, and thus are used to constrain how UV light depends on halo properties, in particular halo mass. The two physical quantities we explore are the star formation duty cycle, and the range of UV luminosity that a halo of mass M can have (mean and variance). The former directly addresses the typical duration of star formation activity in halos while the latter addresses the averaged star formation history and regularity of gas inflow into these systems. In the context of this formalism, we explore various physical models consistent with all the available observational data, and find the following: (1) the typical duration of star formation observed in the data is {approx}< 0.4 Gyr (1{sigma}), (2) the inferred scaling law between the observed L{sub UV} and halo mass M from the observed faint-end slope of the luminosity functions is roughly linear out to M {approx} 10{sup 11.5} - 10{sup 12} h{sup -1} M{sub {circle_dot}} at all redshifts probed in this work, and (3) the observed L{sub UV} for a fixed halo mass M decreases with time, implying that the star formation efficiency (after dust extinction) is higher at earlier times. We explore several different physical scenarios relating star formation to halo mass, but find that these scenarios are indistinguishable due to the limited range of halo mass probed by our data. In order to discriminate between different scenarios, we discuss the possibility of using the bright-faint galaxy cross-correlation functions and more robust determination of luminosity-dependent galaxy bias for future surveys.

  1. THE COMPLEX PHYSICS OF DUSTY STAR-FORMING GALAXIES AT HIGH REDSHIFTS AS REVEALED BY HERSCHEL AND SPITZER

    Energy Technology Data Exchange (ETDEWEB)

    Lo Faro, B.; Franceschini, A.; Vaccari, M.; Rodighiero, G.; Feltre, A.; Marchetti, L. [Dipartimento di Fisica e Astronomia, Universita di Padova, vicolo Osservatorio, 3, I-35122 Padova (Italy); Silva, L. [INAF-OATs, Via Tiepolo 11, I-34131 Trieste (Italy); Berta, S.; Lutz, D.; Magnelli, B. [MPE, Postfach 1312, D-85741, Garching (Germany); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Burgarella, D.; Buat, V. [Laboratoire d' Astrophysique de Marseille, OAMP, Universite Aix-Marseille, CNRS, 38 rue Frederic Joliot-Curie, F-13388 Marseille Cedex 13 (France); Cava, A. [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Farrah, D.; Hurley, P. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Solares, E. A. Gonzalez [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Magdis, G., E-mail: barbara.lofaro@studenti.unipd.it [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); and others

    2013-01-10

    We combine far-infrared photometry from Herschel (PEP/HerMES) with deep mid-infrared spectroscopy from Spitzer to investigate the nature and the mass assembly history of a sample of 31 luminous and ultraluminous infrared galaxies ((U)LIRGs) at z {approx} 1 and 2 selected in GOODS-S with 24 {mu}m fluxes between 0.2 and 0.5 mJy. We model the data with a self-consistent physical model (GRASIL) which includes a state-of-the-art treatment of dust extinction and reprocessing. We find that all of our galaxies appear to require massive populations of old (>1 Gyr) stars and, at the same time, to host a moderate ongoing activity of star formation (SFR {<=} 100 M {sub Sun} yr{sup -1}). The bulk of the stars appear to have been formed a few Gyr before the observation in essentially all cases. Only five galaxies of the sample require a recent starburst superimposed on a quiescent star formation history. We also find discrepancies between our results and those based on optical-only spectral energy distribution (SED) fitting for the same objects; by fitting their observed SEDs with our physical model we find higher extinctions (by {Delta}A {sub V} {approx} 0.81 and 1.14) and higher stellar masses (by {Delta}log(M {sub *}) {approx} 0.16 and 0.36 dex) for z {approx} 1 and z {approx} 2 (U)LIRGs, respectively. The stellar mass difference is larger for the most dust-obscured objects. We also find lower SFRs than those computed from L {sub IR} using the Kennicutt relation due to the significant contribution to the dust heating by intermediate-age stellar populations through 'cirrus' emission ({approx}73% and {approx}66% of the total L {sub IR} for z {approx} 1 and z {approx} 2 (U)LIRGs, respectively).

  2. Impact of Massive Neutrinos and Dark Radiation on the High-redshift Cosmic Web. I. Lyα Forest Observables

    Science.gov (United States)

    Rossi, Graziano

    2017-11-01

    With upcoming high-quality data from surveys such as the Extended Baryon Oscillation Spectroscopic Survey or the Dark Energy Spectroscopic Instrument, improving the theoretical modeling and gaining a deeper understanding of the effects of neutrinos and dark radiation on structure formation at small scales are necessary, to obtain robust constraints free from systematic biases. Using a novel suite of hydrodynamical simulations that incorporate dark matter, baryons, massive neutrinos, and dark radiation, we present a detailed study of their impact on Lyα forest observables. In particular, we accurately measure the tomographic evolution of the shape and amplitude of the small-scale matter and flux power spectra and search for unique signatures along with preferred scales where a neutrino mass detection may be feasible. We then investigate the thermal state of the intergalactic medium (IGM) through the temperature-density relation. Our findings suggest that at k˜ 5 h {{Mpc}}-1 the suppression on the matter power spectrum induced by \\sum {m}ν =0.1 {eV} neutrinos can reach ˜ 4 % at z˜ 3 when compared to a massless neutrino cosmology, and ˜ 10 % if a massless sterile neutrino is included; surprisingly, we also find good agreement (˜ 2 % ) with some analytic predictions. For the 1D flux power spectrum {P}{ F }1{{D}}, the highest response to free-streaming effects is achieved at k˜ 0.005 {[{km}/{{s}}]}-1 when \\sum {m}ν =0.1 {eV}; this k-limit falls in the Lyα forest regime, making the small-scale {P}{ F }1{{D}} an excellent probe for detecting neutrino and dark radiation imprints. Our results indicate that the IGM at z˜ 3 provides the best sensitivity to active and sterile neutrinos.

  3. X-ray Investigations of Quasars with XMM-Newton: Outflow Energetics and High- Redshift Intrinsic Absorption

    Science.gov (United States)

    Brandt, William

    Active Galactic Nuclei (AGNs) are among the most extreme physical environments in the Universe, and it now appears that feedback from AGN winds and jets plays a critical role in the evolution of typical massive galaxies and larger-scale structures. This proposal requests funding to support work on two XMM-Newton guest investigator projects that have already won competitive observing time to study quasars, the most luminous examples of AGNs. The first project is an approved XMM-Newton Large Program that won 350 ks of priority A observation time in AO-9. This project involves an ambitious long-look observation that will obtain the first high-quality grating spectroscopy of a mini-Broad Absorption Line (mini-BAL) quasar, with the aim of assessing the kinetic luminosity of its outflow (the target is PG 1114+445). Grating spectroscopy of a small sample of local Seyfert galaxies has led to highly regarded accurate determinations of their wind properties. The planned extension of grating spectroscopy to the first mini-BAL quasar level AGN will determine if the outflow becomes as powerful as proposed in current AGN feedback scenarios. The 375,000 count EPIC CCD spectra from this long-look will enable unprecedented complementary studies of high-energy absorption features and iron K emission. The data for this project will be gathered over the coming year starting in 2010 May. The second project is an investigation of X-ray absorption in the most-distant radio-loud quasars. Here we are extending our systematic X-ray studies of the most-distant known quasars with XMM-Newton spectroscopy of typical radio-loud quasars (RLQs) at z ~ 4- 5. Our targets are more representative of the overall RLQ population than the small number of highly radio-loud blazars studied at these redshifts. We will search for X-ray absorption in the quasars' environments to determine if it is common among typical RLQs at the highest redshifts. We will also measure X-ray continuum shapes and search for variability and clustered AGNs. Two priority C targets from this project, SDSS J0011+1446 and PMN J0214-0518, were successfully observed as part of XMM-Newton AO-8 (with exposure times of 28 ks and 59 ks, respectively). This proposal is directly relevant to NASA strategic subgoal 3D. It will provide insight into phenomena near black holes (objective 3D.1), and it will address the formation and evolution of galaxies and cosmic structures (objective 3D.2).

  4. Constraints on cold dark matter theories from observations of massive x-ray-luminous clusters of galaxies at high redshift

    Science.gov (United States)

    Luppino, G. A.; Gioia, I. M.

    1995-01-01

    During the course of a gravitational lensing survey of distant, X-ray selected Einstein Observatory Extended Medium Sensitivity Survey (EMSS) clusters of galaxies, we have studied six X-ray-luminous (L(sub x) greater than 5 x 10(exp 44)(h(sub 50)(exp -2))ergs/sec) clusters at redshifts exceeding z = 0.5. All of these clusters are apparently massive. In addition to their high X-ray luminosity, two of the clusters at z approximately 0.6 exhibit gravitationally lensed arcs. Furthermore, the highest redshift cluster in our sample, MS 1054-0321 at z = 0.826, is both extremely X-ray luminous (L(sub 0.3-3.5keV)=9.3 x 10(exp 44)(h(sub 50)(exp -2))ergs/sec) and exceedingly rich with an optical richness comparable to an Abell Richness Class 4 cluster. In this Letter, we discuss the cosmological implications of the very existence of these clusters for hierarchical structure formation theories such as standard Omega = 1 CDM (cold dark matter), hybrid Omega = 1 C + HDM (hot dark matter), and flat, low-density Lambda + CDM models.

  5. NuSTAR AND MULTIFREQUENCY STUDY OF THE TWO HIGH-REDSHIFT BLAZARS S5 0836+710 AND PKS 2149–306

    Energy Technology Data Exchange (ETDEWEB)

    Tagliaferri, G.; Ghisellini, G.; Covino, S.; Sbarrato, T. [INAF—Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (Italy); Perri, M.; Giommi, P.; Puccetti, S. [ASI—Science Data Center, via del Politecnico, I-00133 Rome (Italy); Hayashida, M. [Institute for Cosmic Ray Research, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8582 (Japan); Balokovic, M.; Harrison, F. A. [Cahill Center for Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Madejski, G. M.; Chiang, J. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Boggs, S. E. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E.; Craig, W. W. [DTU Space—National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Zhang, W. W., E-mail: gianpiero.tagliaferri@brera.inaf.it [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2015-07-10

    Powerful blazars are flat-spectrum radio quasars whose emission is dominated by a Compton component peaking between a few hundred keV and a few hundred MeV. We observed two bright blazars, PKS 2149–306 at redshift z = 2.345 and S5 0836+710 at z = 2.172, in the hard X-ray band with the Nuclear Spectroscopic Telescope Array satellite. Simultaneous soft-X-rays and UV–optical observations were performed with the Swift satellite, while near-infrared (near-IR) data were obtained with the Rapid Eye Mount telescope. To study their variability, we repeated these observations for both sources on a timescale of a few months. While no fast variability was detected during a single observation, both sources were variable in the X-ray band, up to 50%, between the two observations, with larger variability at higher energies. No variability was detected in the optical/NIR band. These data, together with Fermi-Large Area Telescope, Wide-field Infrared Survey Explorer, and other literature data, are then used to study the overall spectral energy distributions (SEDs) of these blazars. Although the jet nonthermal emission dominates the SED, it leaves the UV band unhidden, allowing us to detect the thermal emission of the disk and to estimate the black hole mass. The nonthermal emission is well reproduced by a one-zone leptonic model by the synchrotron, self-Compton, and external Compton processes. Our data are better reproduced if we assume that the location of the dissipation region of the jet, R{sub diss}, is in between the torus and the broad-line region. The observed variability is explained by changing a minimum number of model parameters by a very small amount.

  6. Fast-Growing SMBHs in Fast-Growing Galaxies, at High Redshifts: The Role of Major Mergers As Revealed by ALMA

    Directory of Open Access Journals (Sweden)

    Benny Trakhtenbrot

    2017-11-01

    Full Text Available We present a long-term, multi-wavelength project to understand the epoch of fastest growth of the most massive black holes by using a sample of 40 luminous quasars at z ≃ 4.8. These quasars have rather uniform properties, with typical accretion rates and black hole masses of L/LEdd ≃ 0.7 and MBH ≃ 109M⊙. The sample consists of “FIR-bright” sources with a previous Herschel/SPIRE detection, suggesting SFR > 1,000 M⊙ yr−1, as well as of “FIR-faint” sources for which Herschel stacking analysis implies a typical SFR of ~400 M⊙ yr−1. Six of the quasars have been observed by ALMA in [C ii] λ157.74μm line emission and adjacent rest-frame 150μm continuum, to study the dusty cold ISM. ALMA detected companion, spectroscopically confirmed sub-mm galaxies (SMGs for three sources—one FIR-bright and two FIR-faint. The companions are separated by ~14–45 kpc from the quasar hosts, and we interpret them as major galaxy interactions. Our ALMA data therefore clearly support the idea that major mergers may be important drivers for rapid, early SMBH growth. However, the fact that not all high-SFR quasar hosts are accompanied by interacting SMGs, and their ordered gas kinematics observed by ALMA, suggest that other processes may be fueling these systems. Our analysis thus demonstrates the diversity of host galaxy properties and gas accretion mechanisms associated with early and rapid SMBH growth.

  7. POWERFUL ACTIVITY IN THE BRIGHT AGES. I. A VISIBLE/IR SURVEY OF HIGH REDSHIFT 3C RADIO GALAXIES AND QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Hilbert, B.; Chiaberge, M.; Kotyla, J. P.; Sparks, W. B.; Macchetto, F. D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Tremblay, G. R. [Yale University, Department of Astronomy, 260 Whitney Avenue, New Haven, CT 06511 (United States); Stanghellini, C. [INAF—Istituto di Radioastronomia, Via P. Gobetti, 101 I-40129 Bologna (Italy); Baum, S.; O’Dea, C. P. [University of Manitoba, Dept of Physics and Astronomy, 66 Chancellors Circle, Winnipeg, MB R3T 2N2 (Canada); Capetti, A. [Osservatorio Astronomico de Torino, Corso Savona, I-10024 Moncalieri TO (Italy); Miley, G. K. [Universiteit Leiden, Rapenburg 70, 2311 EZ Leiden (Netherlands); Perlman, E. S. [Florida Institute of Technology, 150 W University Boulevard, Melbourne, FL 32901 (United States); Quillen, A. [Rochester Institute of Technology, School of Physics and Astronomy, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2016-07-01

    We present new rest-frame UV and visible observations of 22 high- z (1 < z < 2.5) 3C radio galaxies and QSOs obtained with the Hubble Space Telescope ’s Wide Field Camera 3 instrument. Using a custom data reduction strategy in order to assure the removal of cosmic rays, persistence signal, and other data artifacts, we have produced high-quality science-ready images of the targets and their local environments. We observe targets with regions of UV emission suggestive of active star formation. In addition, several targets exhibit highly distorted host galaxy morphologies in the rest frame visible images. Photometric analyses reveal that brighter QSOs generally tend to be redder than their dimmer counterparts. Using emission line fluxes from the literature, we estimate that emission line contamination is relatively small in the rest frame UV images for the QSOs. Using archival VLA data, we have also created radio map overlays for each of our targets, allowing for analysis of the optical and radio axes alignment.

  8. The Galaxy-Halo Connection in High-redshift Universe: Details and Evolution of Stellar-to-halo Mass Ratios of Lyman Break Galaxies on CFHTLS Deep Fields

    Science.gov (United States)

    Ishikawa, Shogo; Kashikawa, Nobunari; Toshikawa, Jun; Tanaka, Masayuki; Hamana, Takashi; Niino, Yuu; Ichikawa, Kohei; Uchiyama, Hisakazu

    2017-05-01

    We present the results of clustering analyses of Lyman break galaxies (LBGs) at z˜ 3, 4, and 5 using the final data release of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). Deep- and wide-field images of the CFHTLS Deep Survey enable us to obtain sufficiently accurate two-point angular correlation functions to apply a halo occupation distribution analysis. The mean halo masses, calculated as ={10}11.7{--}{10}12.8 {h}-1 {M}⊙ , increase with the stellar-mass limit of LBGs. The threshold halo mass to have a central galaxy, {M}\\min , follows the same increasing trend as the low-z results, whereas the threshold halo mass to have a satellite galaxy, M 1, shows higher values at z=3{--}5 than z=0.5{--}1.5, over the entire stellar mass range. Satellite fractions of dropout galaxies, even at less massive halos, are found to drop sharply, from z = 2 down to less than 0.04, at z=3{--}5. These results suggest that satellite galaxies form inefficiently within dark halos at z=3{--}5, even for less massive satellites with {M}\\star pivot}, which is the halo mass at a peak in the star-formation efficiency, at 3 3. In addition, {M}{{h}}{pivot} and its normalization are found to be almost unchanged during 0< z< 5. Our study provides observational evidence that galaxy formation is ubiquitously most efficient near a halo mass of {M}{{h}}˜ {10}12 {M}⊙ over cosmic time.

  9. NuSTAR and multifrequency study of the two high-redshift blazars S5 0836+710 and PKS 2149-306

    DEFF Research Database (Denmark)

    Tagliaferri, G.; Ghisellini, G.; Perri, M.

    2015-01-01

    Powerful blazars are flat-spectrum radio quasars whose emission is dominated by a Compton component peakingbetween a few hundred keV and a few hundred MeV. We observed two bright blazars, PKS 2149–306 at redshift z = 2.345 and S5 0836+710 at z = 2.172, in the hard X-ray band with the Nuclear...

  10. HiZELS: a high-redshift survey of Hα emitters - I. The cosmic star formation rate and clustering at z = 2.23

    Science.gov (United States)

    Geach, J. E.; Smail, Ian; Best, P. N.; Kurk, J.; Casali, M.; Ivison, R. J.; Coppin, K.

    2008-08-01

    We present results from a near-infrared narrow-band survey of emission-line galaxies at z = 2.23, using the Wide Field Camera on the United Kingdom Infrared Telescope. The H2S1 narrow-band filter (λc = 2.121μm) we employ selects the Hα emission-line redshifted to z = 2.23, and is thus suitable for selecting `typical' star-forming galaxies and active galactic nuclei at this epoch. The pilot study was undertaken in the well-studied Cosmological Evolution Survey field (COSMOS) and is already the largest near-infrared narrow-band survey at this depth, with a line flux limit of FHα ~ 10-16ergs-1cm-2 over 0.60deg2, probing ~220 × 103Mpc3 (comoving) down to a limiting star formation rate of ~30Msolaryr-1 (3σ). In this paper, we present the results from our pilot survey and evaluate the Hα luminosity function and estimate the clustering properties of Hα emitters at z = 2.23 from 55 detected galaxies. The integrated luminosity function is used to estimate the volume-averaged star formation rate at z = 2.23: ρSFR = 0.17+0.16-0.09Msolaryr-1Mpc-3 for LHα > 1042ergs-1. For the first time, we use the Hα star formation tracer to reliably constrain ρSFR out to z = 2.23 demonstrating the rapid increase in ρSFR out to this redshift as well as confirming the flattening in ρSFR between z ~ 1 and 2. In addition to the luminosity distribution, we analyse the clustering properties of these galaxies. Using the two-point angular correlation function, ω(θ), we estimate a real-space correlation length of r0 = 4.2+0.4-0.2h-1Mpc. In comparison to models of clustering which take into account bias evolution, we estimate that these galaxies are hosted by dark matter haloes of mass Mhalo ~ 1012Msolar consistent with the progenitors of the Milky Way. Based on observations obtained with the Wide Field CAMera (WFCAM) on the United Kingdom Infrared Telescope (UKIRT). E-mail: j.e.geach@durham.ac.uk

  11. Fermi-LAT detection of a new gamma-ray source associated with the high-redshift FSRQ TXS 0552+398

    Science.gov (United States)

    Angioni, R.; Cheung, C. C.

    2018-01-01

    The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has observed enhanced gamma-ray emission from a source positionally consistent with the Flat-Spectrum Radio Quasar (FSRQ) TXS 0552+398, also known as B2 0552+39A, with coordinates R.A. = 88.8783567 deg, Decl.

  12. CO-dark molecular gas at high redshift: very large H2 content and high pressure in a low-metallicity damped Lyman alpha system

    Science.gov (United States)

    Balashev, S. A.; Noterdaeme, P.; Rahmani, H.; Klimenko, V. V.; Ledoux, C.; Petitjean, P.; Srianand, R.; Ivanchik, A. V.; Varshalovich, D. A.

    2017-09-01

    We present a detailed analysis of an H2-rich, extremely strong intervening damped Ly α absorption system (DLA) at zabs = 2.786 towards the quasar J 0843+0221, observed with the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. The total column density of molecular (resp. atomic) hydrogen is log N(H2) = 21.21 ± 0.02 (resp. log N(H I) = 21.82 ± 0.11), making it to be the first case in quasar absorption line studies with H2 column density as high as what is seen in 13CO-selected clouds in the Milky Way. We find that this system has one of the lowest metallicity detected among H2-bearing DLAs, with [Zn/H] = -1.52^{+0.08}_{-0.10}. This can be the reason for the marked differences compared to systems with similar H2 column densities in the local Universe: (I) the kinetic temperature, T ˜ 120 K, derived from the J = 0, 1 H2 rotational levels is at least twice higher than expected; (II) there is little dust extinction with AV 2 × 1023 cm-2/(km s-1 K), in the very low metallicity gas. Low CO and high H2 contents indicate that this system represents 'CO-dark/faint' gas. We investigate the physical conditions in the H2-bearing gas using the fine-structure levels of C I, C II, Si II and the rotational levels of HD and H2. We find the number density to be about n ˜ 260-380 cm-3, implying a high thermal pressure of 3-5 × 104 cm-3 K. We further identify a trend of increasing pressure with increasing total hydrogen column density. This independently supports the suggestion that extremely strong DLAs (with log N(H) ˜22) probe high-z galaxies at low impact parameters.

  13. Exploratory X-Ray Monitoring of Luminous Radio-quiet Quasars at High Redshift: No Evidence for Evolution in X-Ray Variability

    Science.gov (United States)

    Shemmer, Ohad; Brandt, W. N.; Paolillo, Maurizio; Kaspi, Shai; Vignali, Cristian; Lira, Paulina; Schneider, Donald P.

    2017-10-01

    We report on the second installment of an X-ray monitoring project of seven luminous radio-quiet quasars (RQQs). New Chandra observations of four of these, at 4.10≤slant z≤slant 4.35, yield a total of six X-ray epochs per source, with temporal baselines of ˜ 850{--}1600 days in the rest frame. These data provide the best X-ray light curves for RQQs at z> 4 to date, enabling qualitative investigations of the X-ray variability behavior of such sources for the first time. On average, these sources follow the trend of decreasing variability amplitude with increasing luminosity, and there is no evidence for X-ray variability increasing toward higher redshifts, in contrast with earlier predictions of potential evolutionary scenarios. An ensemble variability structure function reveals that their variability level remains relatively flat across ≈ 20{--}1000 days in the rest frame and it is generally lower than that of three similarly luminous RQQs at 1.33≤slant z≤slant 2.74 over the same temporal range. We discuss possible explanations for the increased variability of the lower-redshift subsample and, in particular, whether higher accretion rates play a leading role. Near-simultaneous optical monitoring of the sources at 4.10≤slant z≤slant 4.35 indicates that none is variable on ≈ 1 day timescales, although flux variations of up to ˜25% are observed on ≈ 100 day timescales, typical of RQQs at similar redshifts. Significant optical-X-ray spectral slope variations observed in two of these sources are consistent with the levels observed in luminous RQQs and are dominated by X-ray variations.

  14. Gas inflow and outflow in an interacting high-redshift galaxy. The remarkable host environment of GRB 080810 at z = 3.35

    Science.gov (United States)

    Wiseman, P.; Perley, D. A.; Schady, P.; Prochaska, J. X.; de Ugarte Postigo, A.; Krühler, T.; Yates, R. M.; Greiner, J.

    2017-11-01

    We reveal multiple components of an interacting galaxy system at z ≈ 3.35 through a detailed analysis of the exquisite high-resolution Keck/HIRES spectrum of the afterglow of a gamma-ray burst (GRB). Through Voigt-profile fitting of absorption lines from the Lyman series, we constrain the neutral hydrogen column density to NH I ≤ 1018.35 cm-2 for the densest of four distinct systems at the host redshift of GRB 080810, which is among the lowest NH I ever observed in a GRB host, even though the line of sight passes within a projected 5 kpc of the galaxy centres. By detailed analysis of the corresponding metal absorption lines, we derive chemical, ionic, and kinematic properties of the individual absorbing systems, and thus build a picture of the host as a whole. Striking differences between the systems imply that the line of sight passes through several phases of gas: the star-forming regions of the GRB host; enriched material in the form of a galactic outflow; the hot and ionised halo of a second interacting galaxy falling towards the host at a line-of-sight velocity of 700 km s-1; and a cool metal-poor cloud that may represent one of the best candidates yet for the inflow of metal-poor gas from the intergalactic medium. The reduced spectrum is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/607/A107

  15. Observing Star Formation on Sub-Kiloparsec Scales in the High-Redshift (z~1.8) Galaxy SDP.11 Using Gravitational Lensing

    Science.gov (United States)

    Lamarche, Cody James; Stacey, Gordon; Verma, Aprajita; Vishwas, Amit; Nikola, Thomas; Brisbin, Drew; Ferkinhoff, Carl; Hailey-Dunsheath, Steven

    2018-01-01

    Using the Atacama Large Millimeter/submillimeter Array (ALMA), we have recently conducted high-resolution (~ 0.2”) observations of the [CII] 158um line in SDP.11, a strongly lensed source at z ~ 1.8. Accounting for the lensing magnification of 10.9 (Bussmann et al. 2013), these observations are probing the interstellar medium (ISM) of SDP.11 at ~ 500pc scales! These observations are in agreement with our previous Redshift (z) and Early Universe Spectrometer (ZEUS-2) [CII] observations (Ferkinhoff et al. 2014), namely that the mean [CII]/FIR ratio (~0.08%) is consistent with SDP.11 hosting an intense starburst. We additionally see variations in the [CII]/FIR ratio from ~ 0.02 – 0.2% across the source, indicating that the intense star formation is also localized. We spectrally resolve the [CII] line into two velocity components, separated by ~ 320 km/s, which, interestingly, appear in the image plane as two spatially offset Einstein rings, with the dust continuum emission lying neatly between the two. A comparison of the observed 158um dust continuum with the previous lens model indicates that the model needs to be updated to capture the details seen in the higher resolution data.

  16. VERY STRONG EMISSION-LINE GALAXIES IN THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY AND IMPLICATIONS FOR HIGH-REDSHIFT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Atek, H.; Colbert, J.; Shim, H. [Spitzer Science Center, Caltech, Pasadena, CA 91125 (United States); Siana, B.; Bridge, C. [Department of Astronomy, Caltech, Pasadena, CA 91125 (United States); Scarlata, C. [Department of Astronomy, University of Minnesota-Twin Cities, Minneapolis, MN 55455 (United States); Malkan, M.; Ross, N. R. [Department of Physics and Astronomy, University of California, Los Angeles, CA (United States); McCarthy, P.; Dressler, A.; Hathi, N. P. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Teplitz, H. [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States); Henry, A.; Martin, C. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Bunker, A. J. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Fosbury, R. A. E. [Space Telescope-European Coordinating Facility, Garching bei Muenchen (Germany)

    2011-12-20

    The WFC3 Infrared Spectroscopic Parallel Survey uses the Hubble Space Telescope (HST) infrared grism capabilities to obtain slitless spectra of thousands of galaxies over a wide redshift range including the peak of star formation history of the universe. We select a population of very strong emission-line galaxies with rest-frame equivalent widths (EWs) higher than 200 A. A total of 176 objects are found over the redshift range 0.35 < z < 2.3 in the 180 arcmin{sup 2} area that we have analyzed so far. This population consists of young and low-mass starbursts with high specific star formation rates (sSFR). After spectroscopic follow-up of one of these galaxies with Keck/Low Resolution Imaging Spectrometer, we report the detection at z = 0.7 of an extremely metal-poor galaxy with 12 + log(O/H) =7.47 {+-} 0.11. After estimating the active galactic nucleus fraction in the sample, we show that the high-EW galaxies have higher sSFR than normal star-forming galaxies at any redshift. We find that the nebular emission lines can substantially affect the total broadband flux density with a median brightening of 0.3 mag, with some examples of line contamination producing brightening of up to 1 mag. We show that the presence of strong emission lines in low-z galaxies can mimic the color-selection criteria used in the z {approx} 8 dropout surveys. In order to effectively remove low-redshift interlopers, deep optical imaging is needed, at least 1 mag deeper than the bands in which the objects are detected. Without deep optical data, most of the interlopers cannot be ruled out in the wide shallow HST imaging surveys. Finally, we empirically demonstrate that strong nebular lines can lead to an overestimation of the mass and the age of galaxies derived from fitting of their spectral energy distribution (SED). Without removing emission lines, the age and the stellar mass estimates are overestimated by a factor of 2 on average and up to a factor of 10 for the high-EW galaxies. Therefore, the contribution of emission lines should be systematically taken into account in SED fitting of star-forming galaxies at all redshifts.

  17. Impacts of breeder loss on social structure, reproduction and population growth in a social canid.

    Science.gov (United States)

    Borg, Bridget L; Brainerd, Scott M; Meier, Thomas J; Prugh, Laura R

    2015-01-01

    The importance of individuals to the dynamics of populations may depend on reproductive status, especially for species with complex social structure. Loss of reproductive individuals in socially complex species could disproportionately affect population dynamics by destabilizing social structure and reducing population growth. Alternatively, compensatory mechanisms such as rapid replacement of breeders may result in little disruption. The impact of breeder loss on the population dynamics of social species remains poorly understood. We evaluated the effect of breeder loss on social stability, recruitment and population growth of grey wolves (Canis lupus) in Denali National Park and Preserve, Alaska using a 26-year dataset of 387 radiocollared wolves. Harvest of breeding wolves is a highly contentious conservation and management issue worldwide, with unknown population-level consequences. Breeder loss preceded 77% of cases (n = 53) of pack dissolution from 1986 to 2012. Packs were more likely to dissolve if a female or both breeders were lost and pack size was small. Harvest of breeders increased the probability of pack dissolution, likely because the timing of harvest coincided with the breeding season of wolves. Rates of denning and successful recruitment were uniformly high for packs that did not experience breeder loss; however, packs that lost breeders exhibited lower denning and recruitment rates. Breeder mortality and pack dissolution had no significant effects on immediate or longer term population dynamics. Our results indicate the importance of breeding individuals is context dependent. The impact of breeder loss on social group persistence, reproduction and population growth may be greatest when average group sizes are small and mortality occurs during the breeding season. This study highlights the importance of reproductive individuals in maintaining group cohesion in social species, but at the population level socially complex species may be resilient to disruption and harvest through strong compensatory mechanisms. Published 2014. This article is a US Government work and is in the public domain in the USA.

  18. Exploring the Evolutionary Origins of Overimitation: A Comparison across Domesticated and Non-Domesticated Canids

    Science.gov (United States)

    Johnston, Angie M.; Holden, Paul C.; Santos, Laurie R.

    2017-01-01

    When learning from others, human children tend to faithfully copy--or "overimitate"--the actions of a demonstrator, even when these actions are irrelevant for solving the task at hand. We investigate whether domesticated dogs ("Canis familiaris") and dingoes ("Canis dingo") share this tendency to overimitate in three…

  19. Lessons from a non-domestic canid: joint disease in captive raccoon dogs (Nyctereutes procyonoides)

    OpenAIRE

    Lawler, Dennis F.; Richard H. Evans; Petteri Nieminen; Anne-Mari Mustonen; Smith, Gail K.

    2012-01-01

    The purpose of this study was to describe pathological changes of the shoulder, elbow, hip and stifle joints of 16 museum skeletons of the raccoon dog (Nyctereutes procyonoides). The subjects had been held in long-term captivity and were probably used for fur farming or research, thus allowing sufficient longevity for joint disease to become recognisable. The prevalence of disorders that include osteochondrosis, osteoarthritis and changes compatible with hip dysplasia, was surprisingly high. ...

  20. Candidatus Bartonella merieuxii, a Potential New Zoonotic Bartonella Species in Canids from Iraq

    Science.gov (United States)

    2012-09-27

    to blood collection and humanely treated prior to euthanasia , in accordance with the rules of the ethic committee from the US Army feral animal...using an insect PLOS Neglected Tropical Diseases | www.plosntds.org 1 September 2012 | Volume 6 | Issue 9 | e1843 Report Documentation Page Form...Categorical age, sex, and location data was also collected with samples, when possible. Ethics statement All animals were chemically restrained prior

  1. Effects of Intraguild Predation: Evaluating Resource Competition between Two Canid Species with Apparent Niche Separation

    Directory of Open Access Journals (Sweden)

    Adam J. Kozlowski

    2012-01-01

    Full Text Available Many studies determine which habitat components are important to animals and the extent their use may overlap with competitive species. However, such studies are often undertaken after populations are in decline or under interspecific stress. Since habitat selection is not independent of interspecific stress, quantifying an animal's current landscape use could be misleading if the species distribution is suboptimal. We present an alternative approach by modeling the predicted distributions of two sympatric species on the landscape using dietary preferences and prey distribution. We compared the observed habitat use of kit foxes (Vulpes macrotis and coyotes (Canis latrans against their predicted distribution. Data included locations of kit foxes and coyotes, carnivore scat transects, and seasonal prey surveys. Although habitats demonstrated heterogeneity with respect to prey resources, only coyotes showed habitat use designed to maximize access to prey. In contrast, kit foxes used habitats which did not align closely with prey resources. Instead, habitat use by kit foxes represented spatial and behavioral strategies designed to minimize spatial overlap with coyotes while maximizing access to resources. Data on the distribution of prey, their dietary importance, and the species-specific disparities between predicted and observed habitat distributions supports a mechanism by which kit fox distribution is derived from intense competitive interactions with coyotes.

  2. Landscape effects on diets of two canids in Northwestern Texas: A multinomial modeling approach

    Science.gov (United States)

    Lemons, P.R.; Sedinger, J.S.; Herzog, M.P.; Gipson, P.S.; Gilliland, R.L.

    2010-01-01

    Analyses of feces, stomach contents, and regurgitated pellets are common techniques for assessing diets of vertebrates and typically contain more than 1 food item per sampling unit. When analyzed, these individual food items have traditionally been treated as independent, which represents pseudoreplication. When food types are recorded as present or absent, these samples can be treated as multinomial vectors of food items, with each vector representing 1 realization of a possible diet. We suggest such data have a similar structure to capture histories for closed-capture, capturemarkrecapture data. To assess the effects of landscapes and presence of a potential competitor, we used closed-capture models implemented in program MARK into analyze diet data generated from feces of swift foxes (Vulpes velox) and coyotes (Canis latrans) in northwestern Texas. The best models of diet contained season and location for both swift foxes and coyotes, but year accounted for less variation, suggesting that landscape type is an important predictor of diets of both species. Models containing the effect of coyote reduction were not competitive (??QAICc 53.6685), consistent with the hypothesis that presence of coyotes did not influence diet of swift foxes. Our findings suggest that landscape type may have important influences on diets of both species. We believe that multinomial models represent an effective approach to assess hypotheses when diet studies have a data structure similar to ours. ?? 2010 American Society of Mammalogists.

  3. New insights on the history of canids in Oceania based on mitochondrial and nuclear data.

    Science.gov (United States)

    Cairns, Kylie M; Wilton, Alan N

    2016-10-01

    How and when dingoes arrived in Oceania poses a fascinating question for scientists with interest in the historical movements of humans and dogs. The dingo holds a unique position as top terrestrial predator of Australia and exists in a wild state. In the first geographical survey of genetic diversity in the dingo using whole mitochondrial genomes, we analysed 16,428 bp in 25 individuals from five separate populations. We also investigated 13 nuclear loci to compare with the mitochondrial population history patterns. Phylogenetic analyses based upon mitochondrial DNA and nuclear DNA support the hypothesis that there are at least two distinct populations of dingo, one of which occurs in the northwest and the other in the southeast of the continent. Conservative molecular dating based upon mitochondrial DNA suggest that the lineages split approximately 8300 years before present, likely outside Australia but within Oceania. The close relationship between dingoes and New Guinea Singing Dogs suggests that plausibly dingoes spread into Australia via the land bridge between Papua New Guinea and Australia although seafaring introductions cannot be rejected. The geographical distribution of these divergent lineages suggests there were multiple independent dingo immigrations. Importantly, the observation of multiple dingo populations suggests the need for revision of existing conservation and management programs that treat dingoes as a single homogeneous population.

  4. Re-emergence of rabies virus maintained by canid populations in Paraguay.

    Science.gov (United States)

    Amarilla, A C F; Pompei, J C A; Araujo, D B; Vázquez, F A; Galeano, R R; Delgado, L M; Bogado, G; Colman, M; Sanabria, L; Iamamoto, K; Garcia, R; Assis, D; Recalde, R; Martorelli, L F; Quiñones, E; Cabello, A; Martini, M; Cosivi, O; Durigon, E L; Favoretto, S R

    2017-09-14

    Paraguay has registered no human cases of rabies since 2004, and the last case in dogs, reported in 2009, was due to a variant maintained in the common vampire bat "Desmodus rotundus". In 2014, a dog was diagnosed as positive for rabies with aggression towards a boy and all required measures of control were successfully adopted. Epidemiological investigation revealed that the dog was not vaccinated and had been attacked by a crab-eating fox, "zorro" (Cerdocyon thous). The sample was diagnosed by the Official Veterinary Service of the Country and sent to the Center on Rabies Research from the University of São Paulo, Brazil, for antigenic and genetic characterization. A second sample from a dog positive for rabies in the same region in 2015 and 11 samples from a rabies outbreak from Asuncion in 1996 were also characterized. The antigenic profile of the samples, AgV2, was compatible with one of the variants maintained by dogs in Latin America. In genetic characterization, the samples segregated in the canine (domestic and wild species)-related group in an independent subgroup that also included samples from Argentina. These results and the epidemiology of the case indicate that even with the control of rabies in domestic animals, the virus can still circulate in wildlife and may be transmitted to domestic animals and humans, demonstrating the importance of continuous and improved surveillance and control of rabies, including in wild species, to prevent outbreaks in controlled areas. © 2017 Blackwell Verlag GmbH.

  5. Differences in problem-solving between canid populations: Do domestication and lifetime experience affect persistence?

    Science.gov (United States)

    Brubaker, Lauren; Dasgupta, Sandipan; Bhattacharjee, Debottam; Bhadra, Anindita; Udell, Monique A R

    2017-07-01

    Past research has suggested that a variety of factors, phylogenetic and ontogenetic, play a role in how canines behave during problem-solving tasks and the degree to which the presence of a human influences their problem-solving behaviour. While comparisons between socialized wolves and domestic dogs have commonly been used to tease apart these predictive factors, in many cases a single dog population, often pets, have been used for these comparisons. Less is understood about how different populations of dogs may behave when compared with wolves, or with each other, during an independent problem-solving task. This experiment compared the independent persistence of four populations of canines (two groups of pet domestic dogs, a group of free-ranging domestic dogs, and human-socialized wolves) on an independent problem-solving task in the presence of an on looking human. Results showed that wolves persisted the most at the task while free-ranging dogs persisted the least. Free-ranging dogs gazed at the human experimenter for the longest durations during the task. While further research is needed to understand why these differences exist, this study demonstrates that dogs, even those living outside human homes as scavengers, show comparatively low levels of persistence when confronted with a solvable task in the presence of a human as well as significantly greater duration of human-directed gaze when compared with wolves.

  6. Genetic basis for systems of skeletal quantitative traits: Principal component analysis of the canid skeleton

    OpenAIRE

    Chase, Kevin; Carrier, David R.; Frederick R. Adler; Jarvik, Tyler; Ostrander, Elaine A.; Lorentzen, Travis D.; Lark, Karl G.

    2002-01-01

    Evolution of mammalian skeletal structure can be rapid and the changes profound, as illustrated by the morphological diversity of the domestic dog. Here we use principal component analysis of skeletal variation in a population of Portuguese Water Dogs to reveal systems of traits defining skeletal structures. This analysis classifies phenotypic variation into independent components that can be used to dissect genetic networks regulating complex biological systems. We show that unlinked quantit...

  7. VLA Observations of a Complete Sample of Radio Loud Quasars between redshifts 2.5 and 5.28: I. high-redshift sample summary and the radio images

    OpenAIRE

    Gobeille, Doug B.; Wardle, John F. C.; Cheung, C. C.

    2014-01-01

    We present high resolution (arcsecond or better) observations made with the Karl G. Jansky Very Large Array of 123 radio-loud quasars with redshifts in the range $2.5 \\leq z \\leq 5.28$ that form a complete flux limited sample ($\\geq 70$ mJy at 1.4 GHz or 5 GHz). Where possible, we used previous high resolution VLA observations (mainly A array at 1.4, 5 and 8 GHz) from the NRAO archive and re-imaged them (43 sources). For the remainder, new observations were made in the A array at 1.4 and 5 GH...

  8. The MOSDEF Survey: Metallicity Dependence of PAH Emission at High Redshift and Implications for 24 μm Inferred IR Luminosities and Star Formation Rates at z ˜ 2

    Science.gov (United States)

    Shivaei, Irene; Reddy, Naveen A.; Shapley, Alice E.; Siana, Brian; Kriek, Mariska; Mobasher, Bahram; Coil, Alison L.; Freeman, William R.; Sanders, Ryan L.; Price, Sedona H.; Azadi, Mojegan; Zick, Tom

    2017-03-01

    We present results on the variation of 7.7 μm polycyclic aromatic hydrocarbon (PAH) emission in galaxies spanning a wide range in metallicity at z ˜ 2. For this analysis, we use rest-frame optical spectra of 476 galaxies at 1.37 ≤ z ≤ 2.61 from the MOSFIRE Deep Evolution Field (MOSDEF) survey to infer metallicities and ionization states. Spitzer/MIPS 24 μm and Herschel/PACS 100 and 160 μm observations are used to derive rest-frame 7.7 μm luminosities ({L}7.7) and total IR luminosities ({L}{IR}), respectively. We find significant trends between the ratio of {L}7.7 to {L}{IR} (and to dust-corrected star formation rate [SFR]) and both metallicity and [O III]/[O II] ({{{O}}}32) emission line ratio. The latter is an empirical proxy for the ionization parameter. These trends indicate a paucity of PAH emission in low-metallicity environments with harder and more intense radiation fields. Additionally, {L}7.7/{L}{IR} is significantly lower in the youngest quartile of our sample (ages of ≲500 Myr) compared to older galaxies, which may be a result of the delayed production of PAHs by AGB stars. The relative strength of {L}7.7 to {L}{IR} is also lower by a factor of ˜2 for galaxies with masses {M}* {10}10 {M}⊙ , respectively. Based on the new scaling, the SFR-M * relation has a shallower slope than previously derived. Our results also suggest a higher IR luminosity density at z ˜ 2 than previously measured, corresponding to a ˜30% increase in the SFR density.

  9. Revealing the ISM in high redshift starburst galaxies: An analysis of Herschel PACS and SPIRE FTS spectroscopic observations of HerMES and H-ATLAS-selected lensed galaxies

    Science.gov (United States)

    Cooray, Asantha

    In the quest to develop a fundamental understanding of galaxy formation and evolution, observations of dusty star-forming galaxies (DSFGs) promise significant progress this decade. The importance of DSFGs is highlighted by the fact that half of the energy emitted by extragalactic sources emerges as dust-reprocessed light at infrared (IR) to sub millimeter wavelength. In the post-herschel\\ era, we are now at a unique position to tackle some of the key questions on galaxy formation and evolution because of the large area Herschel's Key Project surveys (HerMES and H-ATLAS). In particular those surveys have allowed us to identify a sample of 250 strongly gravitationally lensed DSFGs at z > 1. They give us a unique opportunity to dissect the detailed structures and kinematics of DSFGs. The Herschel Science Archive also contains individual follow up data on 44 and 25 of the brightest sources with SPIRE-FTS and PACS, respectively, in the spectroscopy mode, taking over 250 hours in four open-time programs. Only one of the 44 SPIRE FTS targets has yet to appear in the published literature. One of the four include an open-time 2 PACS spectroscopy program that was led at UCI by a former postdoc from the PI's group. That program was initially approved at Priority 2 in 2011, but was triggered in late 2012 and achieved 100% completion during the last two weeks of Herschel lifetime in May 2013. This archival analysis, interpretation, and modeling program involves two parts: (i) PACS spectroscopy in 50 to 200 microns of 25 lensed galaxies in the fine-structure emission lines [SiII]34, [SIII]33, [OIV]26, [OIII]52, [NIII]57 and [OI]63, and the molecular hydrogen H_2 S(0) and S(1). (ii) SPIRE FTS spectroscopy of 44 lensed galaxies, including above 25, over the wavelength range of 200 to 600 microns targeting [CII]158, [OIII]88, [OI]63/145, and [NI]122. The analysis will lead to a better understanding of the ISM of starbursting galaxies that span 1 z generation astrophysicists in the form of undergraduate students, graduate students, and postdoctoral fellows leading to experience and background in the analysis and interpretation of space-based astronomical data support the Goal 6 of the NASA 2011 Strategic Plan to share NASA with the public, educators, and students to provide opportunities to participate in our Mission, foster innovation, and contribute to a strong national economy. The PI's efforts to involve undergraduates in his research programs will specifically improve retention of students in STEM disciplines by providing opportunities and activities along the full length of the education pipeline (subgoal 6.1).

  10. One Health Interactions of Chagas Disease Vectors, Canid Hosts, and Human Residents along the Texas-Mexico Border.

    Directory of Open Access Journals (Sweden)

    Melissa N Garcia

    2016-11-01

    Full Text Available Chagas disease (Trypanosoma cruzi infection is the leading cause of non-ischemic dilated cardiomyopathy in Latin America. Texas, particularly the southern region, has compounding factors that could contribute to T. cruzi transmission; however, epidemiologic studies are lacking. The aim of this study was to ascertain the prevalence of T. cruzi in three different mammalian species (coyotes, stray domestic dogs, and humans and vectors (Triatoma species to understand the burden of Chagas disease among sylvatic, peridomestic, and domestic cycles.To determine prevalence of infection, we tested sera from coyotes, stray domestic dogs housed in public shelters, and residents participating in related research studies and found 8%, 3.8%, and 0.36% positive for T. cruzi, respectively. PCR was used to determine the prevalence of T. cruzi DNA in vectors collected in peridomestic locations in the region, with 56.5% testing positive for the parasite, further confirming risk of transmission in the region.Our findings contribute to the growing body of evidence for autochthonous Chagas disease transmission in south Texas. Considering this region has a population of 1.3 million, and up to 30% of T. cruzi infected individuals developing severe cardiac disease, it is imperative that we identify high risk groups for surveillance and treatment purposes.

  11. Molecular assessment of the phylogeny and biogeography of a recently diversified endemic group of South American canids (Mammalia: Carnivora: Canidae)

    National Research Council Canada - National Science Library

    Tchaicka, Ligia; Freitas, Thales Renato Ochotorena de; Bager, Alex; Vidal, Stela Luengos; Lucherini, Mauro; Iriarte, Agustín; Novaro, Andres; Geffen, Eli; Garcez, Fabricio Silva; Johnson, Warren E; Wayne, Robert K; Eizirik, Eduardo

    2016-01-01

    ... species of the genus Lycalopex. Phylogenetic and molecular dating analyses supported the inference that this genus has undergone a very recent and rapid radiation, stemming from a common ancestor that lived ca...

  12. One Health Interactions of Chagas Disease Vectors, Canid Hosts, and Human Residents along the Texas-Mexico Border.

    Science.gov (United States)

    Garcia, Melissa N; O'Day, Sarah; Fisher-Hoch, Susan; Gorchakov, Rodion; Patino, Ramiro; Feria Arroyo, Teresa P; Laing, Susan T; Lopez, Job E; Ingber, Alexandra; Jones, Kathryn M; Murray, Kristy O

    2016-11-01

    Chagas disease (Trypanosoma cruzi infection) is the leading cause of non-ischemic dilated cardiomyopathy in Latin America. Texas, particularly the southern region, has compounding factors that could contribute to T. cruzi transmission; however, epidemiologic studies are lacking. The aim of this study was to ascertain the prevalence of T. cruzi in three different mammalian species (coyotes, stray domestic dogs, and humans) and vectors (Triatoma species) to understand the burden of Chagas disease among sylvatic, peridomestic, and domestic cycles. To determine prevalence of infection, we tested sera from coyotes, stray domestic dogs housed in public shelters, and residents participating in related research studies and found 8%, 3.8%, and 0.36% positive for T. cruzi, respectively. PCR was used to determine the prevalence of T. cruzi DNA in vectors collected in peridomestic locations in the region, with 56.5% testing positive for the parasite, further confirming risk of transmission in the region. Our findings contribute to the growing body of evidence for autochthonous Chagas disease transmission in south Texas. Considering this region has a population of 1.3 million, and up to 30% of T. cruzi infected individuals developing severe cardiac disease, it is imperative that we identify high risk groups for surveillance and treatment purposes.

  13. Dog Days on the Plains : A Preliminary aDNA Analysis of Canid Bones from Southern Alberta and Saskatchewan

    NARCIS (Netherlands)

    Bartholdy, B.P.; Murchie, T.J.; Hacking, K.; Verwoerd, C.

    2017-01-01

    Dogs were an important component of lifeways on the Northern Plains until the reintroduction of the horse following European contact. There has been little investigation into the variability of domesticcanids on the Prairies and the potential of that variability as a proxy for identifying

  14. Molecular assessment of the phylogeny and biogeography of a recently diversified endemic group of South American canids (Mammalia: Carnivora: Canidae

    Directory of Open Access Journals (Sweden)

    Ligia Tchaicka

    Full Text Available Abstract To investigate the evolution and biogeography of an endemic group of South American foxes, we examined mitochondrial DNA control region sequences for 118 individuals belonging to all six extant species of the genus Lycalopex. Phylogenetic and molecular dating analyses supported the inference that this genus has undergone a very recent and rapid radiation, stemming from a common ancestor that lived ca. 1 million years ago. The Brazilian endemic L. vetulus was supported as the most basal species in this genus, whereas the most internal group is comprised by the recently diverged (ca. 350,000 years ago Andean/Patagonian species L. griseus and L. culpaeus. We discuss the inferred phylogenetic relationships and divergence times in the context of the current geographic distributions of these species, and the likely effects of Pleistocene climatic changes on the biogeography of this group. Furthermore, a remarkable finding was the identification of multiple individuals classified as L. gymnocercus bearing mtDNA haplotypes clearly belonging to L. griseus, sampled in regions where the latter is not known to occur. At a minimum, this result implies the need to clarify the present-day geographic distribution of each of these fox species, while it may also indicate an ongoing hybridization process between them. Future testing of this hypothesis with in-depth analyses of these populations is thus a priority for understanding the history, evolutionary dynamics and present-day composition of this endemic Neotropical genus.

  15. Variations in Canonical Star-Forming Laws at Low Metallicity

    Science.gov (United States)

    Monkiewicz, Jacqueline; Bowman, Judd D.; Scowen, Paul

    2018-01-01

    Empirically-determined star formation relations link observed galaxy luminosities to extrapolated star formation rates at almost every observable wavelength range. These laws are a cornerstone of extragalactic astronomy, and will be critically important for interpreting upcoming observations of early high-redshift protogalaxies with JWST and WFIRST. There are indications at a variety of wavelengths that these canonical relations may become unreliable at the lowest metallicities observed. This potentially complicates interpretation of the earliest protogalaxies, which are expected to be pristine and largely unenriched by stellar nucleosynthesis. Using a sample of 15 local dwarf galaxies with 12+[O/H] focus on two of these relations: the far-infrared/radio relation and the H-alpha/ultraviolet relation. The sample is chosen to have pre-existing far-IR and UV observations, and to span the full spread of the galaxy mass-metallicity relationship at low luminosity, so that luminosity and metallicity may be examined separately. Radio continuum observations of low metallicity dwarf galaxies 1 Zw 18 and SBS 0335-052E suggest that the far-IR/radio relation probably deviates at low metallicities, but the low luminosity end of the relation is not well sampled. The upgraded Jansky Very Large Array has the sensitivity to fill in this gap. I have obtained 45 hours of L- and C-band continuum data of my dwarf galaxy sample. I present radio continuum imaging of an initial sub-sample of Local Group dwarfs, some of which have never before been detected in radio continuum. The H-alpha/UV relationship is likewise known to become unreliable for dwarf galaxies, though this has been attributed to dwarf galaxy "bursty-ness" rather than metallicity effects. I have conducted a parallel survey of emission line imaging to study the underlying astrophysics of the H-alpha/UV relation. Using Balmer decrement imaging, I map out the pixel-to-pixel dust distribution and geometry within the nearest

  16. Monolithic View of Galaxy Formation and Evolution

    Directory of Open Access Journals (Sweden)

    Cesare Chiosi

    2014-07-01

    Full Text Available We review and critically discuss the current understanding of galaxy formation and evolution limited to Early Type Galaxies (ETGs as inferred from the observational data and briefly contrast the hierarchical and quasi-monolithic paradigms of formation and evolution. Since in Cold Dark Matter (CDM cosmogony small scale structures typically collapse early and form low-mass haloes that subsequently can merge to assembly larger haloes, galaxies formed in the gravitational potential well of a halo are also expected to merge thus assembling their mass hierarchically. Mergers should occur all over the Hubble time and large mass galaxies should be in place only recently. However, recent observations of high redshift galaxies tell a different story: massive ETGs are already in place at high redshift. To this aim, we propose here a revision of the quasi-monolithic scenario as an alternative to the hierarchical one, in which mass assembling should occur in early stages of a galaxy lifetime and present recent models of ETGs made of Dark and Baryonic Matter in a Λ-CDM Universe that obey the latter scheme. The galaxies are followed from the detachment from the linear regime and Hubble flow at z ≥ 20 down to the stage of nearly complete assembly of the stellar content (z ∼ 2 − 1 and beyond.  It is found that the total mass (Mh = MDM + MBM and/or initial over-density of the proto-galaxy drive the subsequent star formation histories (SFH. Massive galaxies (Mh ~ _1012M⊙ experience a single, intense burst of star formation (with rates ≥ 103M⊙/yr at early epochs, consistently with observations, with a weak dependence on the initial over-density; intermediate mass haloes (Mh~_ 1010 − 1011M⊙ have star formation histories that strongly depend on their initial over-density; finally, low mass haloes (Mh ~_ 109M⊙ always have erratic, burst-like star forming histories. The present-day properties (morphology, structure, chemistry and photometry of the

  17. Are the Formation and Abundances of Metal-poor Stars the Result of Dust Dynamics?

    Science.gov (United States)

    Hopkins, Philip F.; Conroy, Charlie

    2017-02-01

    Large dust grains can fluctuate dramatically in their local density, relative to the gas, in neutral turbulent disks. Small, high-redshift galaxies (before reionization) represent ideal environments for this process. We show via simple arguments and simulations that order-of-magnitude fluctuations are expected in local abundances of large grains (>100 Å) under these conditions. This can have important consequences for star formation and stellar metal abundances in extremely metal-poor stars. Low-mass stars can form in dust-enhanced regions almost immediately after some dust forms even if the galaxy-average metallicity is too low for fragmentation to occur. We argue that the metal abundances of these “promoted” stars may contain interesting signatures as the CNO abundances (concentrated in large carbonaceous grains and ices) and Mg and Si (in large silicate grains) can be enhanced and/or fluctuate almost independently. Remarkably, the otherwise puzzling abundance patterns of some metal-poor stars can be well fit by standard IMF-averaged core-collapse SNe yields if we allow for fluctuating local dust-to-gas ratios. We also show that the observed log-normal distribution of enhancements in these species agrees with our simulations. Moreover, we confirm that Mg and Si are correlated in these stars the abundance ratios are similar to those in local silicate grains. Meanwhile [Mg/Ca], predicted to be nearly invariant from pure SNe yields, shows very large enhancements and variations up to factors of ≳100 as expected in the dust-promoted model, preferentially in the [C/Fe]-enhanced metal-poor stars. Together, this suggests that (1) dust exists in second-generation star formation, (2) local dust-to-gas ratio fluctuations occur in protogalaxies and can be important for star formation, and (3) the light element abundances of these stars may be affected by the local chemistry of dust where they formed, rather than directly tracing nucleosynthesis from earlier

  18. First data on canids depredation on livestock in an area of recent recolonization by wolf in central Italy : considerations on conflict survey and prevention methods

    Directory of Open Access Journals (Sweden)

    Magrini Caterina

    2014-03-01

    Full Text Available Wolf and dog depredation on livestock in the province of Rieti, central Italy, in 2007-2008, was studied. The study area was characterized by a high degree of human disturbance, widespread presence of free ranging dogs and a recent wolf recolonization. Because of the ineffectiveness of compensation programmes, it was not possible to use the official statistics to investigate the extent of the conflict, but sample interviews and surveys of farmers were used. Also, the farming protection tecniques adopted for different livestock species were analysed; the most utilized husbandry method was stabling for cattle and pigs, annual fenced grazing for horses and sheeps, and annual open grazing only for goats. Although sheep farms were the most attacked because of their availability (33.6% of the whole farms, goat farms were the most selected by predators because of their accessibility (40% of farms kept goats in annual open grazing. Management implications to mitigate livestock depredation were discussed.

  19. Star formation rates and stellar masses in z ~ 1 gamma-ray burst hosts

    DEFF Research Database (Denmark)

    Castro Cerón, José María; Michalowski, Michal; Hjorth, J.

    2006-01-01

    Cosmology: Observations, ISM: Dust, Extinction, Galaxies: High-Redshift, Galaxies: ISM, Gamma Rays: Bursts, Infrared: Galaxies Udgivelsesdato: Dec. 4......Cosmology: Observations, ISM: Dust, Extinction, Galaxies: High-Redshift, Galaxies: ISM, Gamma Rays: Bursts, Infrared: Galaxies Udgivelsesdato: Dec. 4...

  20. Velocity-metallicity correlation for high-z DLA galaxies

    DEFF Research Database (Denmark)

    Ledoux, C.; Petitjean, P.; Fynbo, J.P.U.

    2006-01-01

    Galaxies: halos, galaxies: high-redshift, galaxies: ISM, quasars: absorption lines, cosmology: observations Udgivelsesdato: Oct.......Galaxies: halos, galaxies: high-redshift, galaxies: ISM, quasars: absorption lines, cosmology: observations Udgivelsesdato: Oct....

  1. Detection of Lyman/alpha emission from a DLA galaxy

    DEFF Research Database (Denmark)

    Moller, P.; Fynbo, Johan Peter Uldall; Fall, S.M

    2004-01-01

    HIGH-REDSHIFT; BREAK GALAXIES; STARFORMATION; DISK GALAXIES; METAL ENRICHMENT; HOST GALAXY; ABSORPTION; ABSORBER; SYSTEMS; SPECTROSCOPY......HIGH-REDSHIFT; BREAK GALAXIES; STARFORMATION; DISK GALAXIES; METAL ENRICHMENT; HOST GALAXY; ABSORPTION; ABSORBER; SYSTEMS; SPECTROSCOPY...

  2. The evolution of the brain in Canidae (Mammalia: Carnivora)

    NARCIS (Netherlands)

    Lyras, G.A.

    2009-01-01

    Canid brain evolution followed three independent, yet convergent paths. Each of the three canid subfamilies (Hesperocyoninae, Borophaginae and Caninae) started with a simple brain, which gradually became more complicated as the cerebral cortex became larger and more fissured, the cerebellar

  3. On the activity of two medium-sized canids: the Golden Jackal (Canis aureus and the Red Fox (Vulpes vulpes in the Natural Bark “Sinite Kamani” (Bulgaria revealed by camera traps

    Directory of Open Access Journals (Sweden)

    ALEXANDAR MECHEV

    2015-01-01

    Full Text Available Daylight activity in both species was often registered during the cold seasons. Foxes were registered to be active between 7-9h and 12-14h, while the jackals – during the whole day. Activity of both predators was rising during the night. The number of photographs increased from around 17h and activity was high until morning around 9-10h.

  4. Probing Magnetic Fields of Early Galaxies

    Science.gov (United States)

    Kohler, Susanna

    2017-06-01

    How do magnetic fields form and evolve in early galaxies? A new study has provided some clever observations to help us answer this question.The Puzzle of Growing FieldsDynamo theory is the primary model describing how magnetic fields develop in galaxies. In this picture, magnetic fields start out as weak seed fields that are small and unordered. These fields then become ordered and amplified by large-scale rotation and turbulence in galaxy disks and halos, eventually leading to the magnetic fields we observe in galaxies today.Schematic showinghow to indirectly measure protogalactic magnetic fields. The measured polarization of a background quasar is altered by the fields in a foreground protogalaxy. Click for a closer look! [Farnes et al. 2017/Adolf Schaller/STSCI/NRAO/AUI/NSF]To test this model, we need observations of the magnetic fields in young protogalaxies. Unfortunately, we dont have the sensitivity to be able to measure these fields directly but a team of scientists led by Jamie Farnes (Radboud University in the Netherlands) have come up with a creative alternative.The key is to find early protogalaxies that absorb the light of more distant background objects. If a protogalaxy lies between us and a distant quasar, then magnetic fields of the protogalaxy if present will affect the polarization measurements of the background quasar.Observing Galactic Building BlocksTop: Redshift distribution for the background quasars in the authors sample. Bottom: Redshift distribution for the foreground protogalaxies the authors are exploring. [Farnes et al. 2017]Farnes and collaborators examined two types of foreground protogalaxies: Damped Lyman-Alpha Absorbers (DLAs) and Lyman Limit Systems (LLSs). They obtained polarimetric data for a sample of 114 distant quasars with nothing in the foreground (the control sample), 19 quasars with DLAs in the foreground, and 27 quasars with LLSs in the foreground. They then used statistical analysis techniques to draw conclusions about

  5. Silicon depletion in damped Ly α systems. The S/Zn method

    NARCIS (Netherlands)

    Vladilo, G.; Abate, C.|info:eu-repo/dai/nl/328199362; Yin, J.; Cescutti, G.; Matteucci, F.

    2011-01-01

    Silicates are an important component of interstellar dust that has been poorly investigated in high redshift galaxies. As a preliminary step to studying silicates at high redshift, we survey silicon depletions in damped Ly α (DLA) systems. Silicon depletion is mild in the Galactic interstellar

  6. LOFAR VLBI studies at 55 MHz of 4C 43.15, a z = 2.4 radio galaxy

    NARCIS (Netherlands)

    Morabito, Leah K.; Deller, Adam T.; Röttgering, Huub; Miley, George; Varenius, Eskil; Shimwell, Timothy W.; Moldón, Javier; Jackson, Neal; Morganti, Raffaella; van Weeren, Reinout J.; Oonk, J. B. R.

    2016-01-01

    The correlation between radio spectral index and redshift has been exploited to discover high-redshift radio galaxies, but its underlying cause is unclear. It is crucial to characterize the particle acceleration and loss mechanisms in high-redshift radio galaxies to understand why their radio

  7. An X-Ray-selected Active Galactic Nucleus at z=4.6 Discovered by the CYDER Survey

    NARCIS (Netherlands)

    Treister, E.; Castander, F.J.; Maccarone, T.J.; Herrera, D.; Gawiser, E.; Maza, J.; Coppi, P.S.

    2004-01-01

    We present the discovery of a high-redshift, X-ray-selected active galactic nucleus (AGN) by the Calan-Yale Deep Extragalactic Research (CYDER) survey: CXOCY J033716.7-050153, located at z=4.61, the second high-redshift AGN discovered by this survey. Here we present its optical, near-IR, and X-ray

  8. Echinococcus multilocularis in Urban Coyotes, Alberta, Canada

    Science.gov (United States)

    Catalano, Stefano; Lejeune, Manigandan; Liccioli, Stefano; Verocai, Guilherme G.; Gesy, Karen M.; Jenkins, Emily J.; Kutz, Susan J.; Fuentealba, Carmen; Duignan, Padraig J.

    2012-01-01

    Echinococcus multilocularis is a zoonotic parasite in wild canids. We determined its frequency in urban coyotes (Canis latrans) in Alberta, Canada. We detected E. multilocularis in 23 of 91 coyotes in this region. This parasite is a public health concern throughout the Northern Hemisphere, partly because of increased urbanization of wild canids. PMID:23017505

  9. Dissipational galaxy formation - Confrontation with observations

    Science.gov (United States)

    Silk, J.; Norman, C.

    1981-01-01

    An exploration is presented of the hypothesis that a protogalaxy consists of an aggregate of interacting gas clouds which undergo mergers with neighboring systems, as envisaged by both the hierarchical clustering and fragmentation schemes of galaxy formation. Both gaseous dissipation and violet relaxation play fundamental roles in this galaxy formation model, in order to account for such diverse structural and dynamical properties of spheroidal galaxies as velocity anisotropy and metallicity gradients. Protogalaxy mergers during the initial stages of galaxy clustering can account for the observed spatial distribution of spiral, S0, and elliptical galaxies, and galaxy formation can occur slowly and at late epochs, since the time scale for disk formation is less than about 10 to the 10th years.

  10. Assessing the Observability of Hypernovae and Pair-Instability Supernovae in the Early Universe

    OpenAIRE

    Wiggins, Brandon K.; Smidt, Joseph M.; Whalen, Daniel J.; Even, Wesley P.; Migenes, Victor; Fryer, Chris L.

    2015-01-01

    The era of the universe's first (Population III) stars is essentially unconstrained by observation. Ultra-luminous and massive stars from this time altered the chemistry of the cosmos, provided the radiative scaffolding to support the formation of the first protogalaxies, and facilitated the creation and growth of now-supermassive black holes. Unfortunately, because these stars lie literally at the edge of the observable universe, they will remain beyond the reach of even the next generation ...

  11. Emission Line Astronomy - Coronagraphic Tunable Narrow Band Imaging and Integral Field Spectroscopy. Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to continue our program of emission line astronomy featuring three areas of emphasis: 1) The distribution and nature of high redshift emission line...

  12. Galaxy population properties of the massive X-ray luminous galaxy cluster XDCP J0044.0-2033 at z = 1.58. Red-sequence formation, massive galaxy assembly, and central star formation activity

    National Research Council Canada - National Science Library

    Fassbender, R; Nastasi, A; Santos, J. S; Lidman, C; Verdugo, M; Koyama, Y; Rosati, P; Pierini, D; Padilla, N; Romeo, A. D; Menci, N; Bongiorno, A; Castellano, M; Cerulo, P; Fontana, A; Galametz, A; Grazian, A; Lamastra, A; Pentericci, L; Sommariva, V; Strazzullo, V; Šuhada, R; Tozzi, P

    2014-01-01

    Context. Recent observational progress has enabled the detection of galaxy clusters and groups out to very high redshifts and for the first time allows detailed studies of galaxy population properties...

  13. Human cystic echinococcosis in South Africa

    NARCIS (Netherlands)

    Mogoye, Benjamin; Menezes, Colin N.; Grobusch, Martin P.; Wahlers, Kerstin; Frean, John

    2012-01-01

    Cystic echinococcosis (CE) is caused by the tapeworm, Echinococcus granulosus. The tapeworms resides in the small intestines of canids and the lifecycle involves both intermediate and definitive hosts. Humans are accidental intermediate hosts. Cystic echinococcosis is an economically important

  14. Records of the Bush Dog (Speothos venaticus) in Central Amazonia, Brazil

    National Research Council Canada - National Science Library

    Daniel Gomes da Rocha; Emiliano Esterci Ramalho; Guilherme Costa Alvarenga; Diogo Maia Gräbin; William Ernest Magnusson

    2015-01-01

    The bush dog (Speothos venaticus) is a small Neotropical canid. Although its distribution covers the entire Amazon basin, the occurrence of bush dogs in vast areas of the Amazon remains hypothetical...

  15. Bilateral fractures of the coronoid processes: differential diagnosis of intra-oral gunshot trauma and scavenging using a sheep crania model.

    Science.gov (United States)

    Puskas, Cathy M

    2003-11-01

    Approximately half of the skeleton of an adult male (minus the cranium) was found in a forested part of Greater Vancouver, Canada, in August 2000 by the Royal Canadian Mounted Police (RCMP). Authorities ruled the death as suicide. The only compelling signs of perimortem trauma were symmetrically fractured coronoid processes of the mandible, which can be attributed to a gunshot in the mouth. However, the remains had also been scavenged by canids, raising a problem in differential diagnosis. Could canid scavenging produce bilateral fracturing of the mandible indistinguishable from gunshot wounds to the mouth? We found that canid scavengers could not mimic the type of damage to the mandible caused by intra-oral gunshot wounding using a sheep model (n = 20). Bilateral fracturing of the coronoid processes was found to be characteristic of intra-oral gunshot wounding, while canid scavengers typically ignore this region of the mandible.

  16. On a Dhole Trail: Examining Ecological and Anthropogenic Correlates of Dhole Habitat Occupancy in the Western Ghats of India

    OpenAIRE

    Arjun Srivathsa; Karanth, Krithi K.; Devcharan Jathanna; N Samba Kumar; Ullas Karanth, K.

    2014-01-01

    Although they play a critical role in shaping ecological communities, many threatened predator species are data-deficient. The Dhole Cuon alpinus is one such rare canid with a global population thought to be

  17. Feedback from Clustered Sources During Reionization

    OpenAIRE

    Kramer, Roban Hultman; Haiman, Zoltan; Oh, S. Peng

    2006-01-01

    The reionization history of the intergalactic medium (IGM) at high redshift (z > 6) was likely strongly shaped by several global feedback processes. Because the earliest ionizing sources formed at the locations of the rare density peaks, their spatial distribution was strongly clustered. Here we demonstrate that this clustering significantly boosts the impact of feedback processes operating at high redshift. We build a semi-analytical model to include feedback and clustering simultaneously, a...

  18. Gravitational Wave Sirens as a Triple Probe of Dark Energy

    OpenAIRE

    Linder, Eric V.

    2007-01-01

    Gravitational wave standard sirens have been considered as precision distance indicators to high redshift; however, at high redshift standard sirens or standard candles such as supernovae suffer from lensing noise. We investigate lensing noise as a signal instead and show how measurements of the maximum demagnification (minimum convergence) probe cosmology in a highly complementary manner to the distance itself. Revisiting the original form for minimum convergence we quantify the bias arising...

  19. First evidence of hybridization between golden jackal (Canis aureus) and domestic dog (Canis familiaris) as revealed by genetic markers

    OpenAIRE

    Galov, Ana; Fabbri, Elena; Caniglia, Romolo; Arbanasi?, Haidi; Lapalombella, Silvana; Florijan?i?, Tihomir; Bo?kovi?, Ivica; Galaverni, Marco; Randi, Ettore

    2015-01-01

    Interspecific hybridization is relatively frequent in nature and numerous cases of hybridization between wild canids and domestic dogs have been recorded. However, hybrids between golden jackals (Canis aureus) and other canids have not been described before. In this study, we combined the use of biparental (15 autosomal microsatellites and three major histocompatibility complex (MHC) loci) and uniparental (mtDNA control region and a Y-linked Zfy intron) genetic markers to assess the admixed o...

  20. Transmission of Neospora caninum between wild and domestic animals

    Science.gov (United States)

    Gondim, L.F.P.; McAllister, M.M.; Mateus-Pinilla, N. E.; Pitt, W.; Mech, L.D.; Nelson, M.E.; Lenarz, M.S.

    2004-01-01

    Neospora caninum is a protozoan parasite that can cause abortions in cows. N. caninum antibody seroprevalence was detected in 64/164 (39%) free-ranging gray wolves from Minnesota, 30/150 (20%) white-tailed deer, and 8/61 (13%) moose. These data are consistent with a sylvatic transmission cycle of N. caninum between cervids and canids. Infection of canids increases the risk of transmitting the parasite to domestic livestock.

  1. Potential Sources of High Frequency and Biphonic Vocalization in the Dhole (Cuon alpinus.

    Directory of Open Access Journals (Sweden)

    Roland Frey

    Full Text Available Biphonation, i.e. two independent fundamental frequencies in a call spectrum, is a prominent feature of vocal activity in dog-like canids. Dog-like canids can produce a low (f0 and a high (g0 fundamental frequency simultaneously. In contrast, fox-like canids are only capable of producing the low fundamental frequency (f0. Using a comparative anatomical approach for revealing macroscopic structures potentially responsible for canid biphonation, we investigated the vocal anatomy for 4 (1 male, 3 female captive dholes (Cuon alpinus and for 2 (1 male, 1 female wild red fox (Vulpes vulpes. In addition, we analyzed the acoustic structure of vocalizations in the same dholes that served postmortem as specimens for the anatomical investigation. All study dholes produced both high-frequency and biphonic calls. The anatomical reconstructions revealed that the vocal morphologies of the dhole are very similar to those of the red fox. These results suggest that the high-frequency and biphonic calls in dog-like canids can be produced without specific anatomical adaptations of the sound-producing structures. We discuss possible production modes for the high-frequency and biphonic calls involving laryngeal and nasal structures.

  2. First evidence of hybridization between golden jackal (Canis aureus) and domestic dog (Canis familiaris) as revealed by genetic markers.

    Science.gov (United States)

    Galov, Ana; Fabbri, Elena; Caniglia, Romolo; Arbanasić, Haidi; Lapalombella, Silvana; Florijančić, Tihomir; Bošković, Ivica; Galaverni, Marco; Randi, Ettore

    2015-12-01

    Interspecific hybridization is relatively frequent in nature and numerous cases of hybridization between wild canids and domestic dogs have been recorded. However, hybrids between golden jackals (Canis aureus) and other canids have not been described before. In this study, we combined the use of biparental (15 autosomal microsatellites and three major histocompatibility complex (MHC) loci) and uniparental (mtDNA control region and a Y-linked Zfy intron) genetic markers to assess the admixed origin of three wild-living canids showing anomalous phenotypic traits. Results indicated that these canids were hybrids between golden jackals and domestic dogs. One of them was a backcross to jackal and another one was a backcross to dog, confirming that golden jackal-domestic dog hybrids are fertile. The uniparental markers showed that the direction of hybridization, namely females of the wild species hybridizing with male domestic dogs, was common to most cases of canid hybridization. A melanistic 3bp-deletion at the K locus (β-defensin CDB103 gene), that was absent in reference golden jackal samples, but was found in a backcross to jackal with anomalous black coat, suggested its introgression from dogs via hybridization. Moreover, we demonstrated that MHC sequences, although rarely used as markers of hybridization, can be also suitable for the identification of hybrids, as long as haplotypes are exclusive for the parental species.

  3. Potential Sources of High Frequency and Biphonic Vocalization in the Dhole (Cuon alpinus).

    Science.gov (United States)

    Frey, Roland; Volodin, Ilya A; Fritsch, Guido; Volodina, Elena V

    2016-01-01

    Biphonation, i.e. two independent fundamental frequencies in a call spectrum, is a prominent feature of vocal activity in dog-like canids. Dog-like canids can produce a low (f0) and a high (g0) fundamental frequency simultaneously. In contrast, fox-like canids are only capable of producing the low fundamental frequency (f0). Using a comparative anatomical approach for revealing macroscopic structures potentially responsible for canid biphonation, we investigated the vocal anatomy for 4 (1 male, 3 female) captive dholes (Cuon alpinus) and for 2 (1 male, 1 female) wild red fox (Vulpes vulpes). In addition, we analyzed the acoustic structure of vocalizations in the same dholes that served postmortem as specimens for the anatomical investigation. All study dholes produced both high-frequency and biphonic calls. The anatomical reconstructions revealed that the vocal morphologies of the dhole are very similar to those of the red fox. These results suggest that the high-frequency and biphonic calls in dog-like canids can be produced without specific anatomical adaptations of the sound-producing structures. We discuss possible production modes for the high-frequency and biphonic calls involving laryngeal and nasal structures.

  4. The cosmic web and microwave background fossilize the first turbulent combustion

    Science.gov (United States)

    Gibson, Carl H.; Keeler, R. Norris

    2016-10-01

    Collisional fluid mechanics theory predicts a turbulent hot big bang at Planck conditions from large, negative, turbulence stresses below the Fortov-Kerr limit (Big bang turbulence fossilized when quarks formed, extracting the mass energy of the universe by extreme negative viscous stresses of inflation, expanding to length scales larger than the horizon scale ct. Viscous-gravitational structure formation by fragmentation was triggered at big bang fossil vorticity turbulence vortex lines during the plasma epoch, as observed by the Planck space telescope. A cosmic web of protogalaxies, protogalaxyclusters, and protogalaxysuperclusters that formed in turbulent boundary layers of the spinning voids are hereby identified as expanding turbulence fossils that falsify CDMHC cosmology.

  5. Can Primordial Magnetic Fields Seeded by Electroweak Strings Cause an Alignment of Quasar Axes on Cosmological Scales?

    Science.gov (United States)

    Poltis, Robert; Stojkovic, Dejan

    2010-10-01

    The decay of nontopological electroweak strings may leave an observable imprint in the Universe today in the form of primordial magnetic fields. Protogalaxies preferentially tend to form with their axis of rotation parallel to an external magnetic field, and, moreover, an external magnetic field produces torque which tends to align the galaxy axis with the magnetic field. We demonstrate that the shape of a magnetic field left over from two looped electroweak strings can explain the observed nontrivial alignment of quasar polarization vectors and make predictions for future observations.

  6. XRED

    DEFF Research Database (Denmark)

    Krumpe, Mirko; Coffey, Deirdre; Egger, Georg

    2005-01-01

    redshifted GRBs, in order to probe the nature of the first generation of stars and hence the time of reionisation of the early Universe. We demonstrate that the gamma and x-ray luminosities of typical GRBs render them detectable up to extremely high redshifts (z ~ 10to30), but that current missions...... to detect high redshift gamma-rays, an x-ray focussing telescope to determine accurate coordinates and extract spectra, and an infrared spectrograph to observe the high redshift optical afterglow. The mission is expected to detect and identify for the first time GRBs with z > 10, thereby providing...... constraints on properties of the first generation of stars and the history of the early Universe....

  7. On inferring extinction laws in z ~ 6 quasars as signatures of supernova dust

    DEFF Research Database (Denmark)

    Hjorth, Jens; Vreeswijk, P.M.; Gall, C.

    2013-01-01

    Unusual extinction curves of high-redshift QSOs have been taken as evidence that dust is primarily produced by supernovae at high redshift. In particular, the 3000 Å Todini-Ferrara-Maiolino kink in the extinction curve of the z = 6.20 SDSS J1048+4637 has been attributed to supernova dust. Here we...... discuss the challenges in inferring robust extinction curves of high-redshift QSOs and critically assess previous claims of detection of supernova dust. In particular, we address the sensitivity to the choice of intrinsic QSO spectrum, the need for a long wavelength baseline, and the drawbacks in fitting...... theoretical extinction curves. In a sample of 21 QSOs at z ~ 6 we detect significant ultraviolet extinction using existing broadband optical, near-infrared, and Spitzer photometry. The median extinction curve is consistent with a Small Magellanic Cloud curve with A ~ 0.7 mag and does not exhibit any...

  8. On the Brightness of Supernova Ia

    CERN Document Server

    Zheng, Yijia

    2013-01-01

    Before 1998 the universe expansion was thought to be slowing down. After 1998 the universe expansion is thought to be accelerating up. The key evidence came from the observed brightness of high redshift supernovae Ia in 1998. Astronomers found that the observed brightness of high redshift supernovae Ia is fainter than expected. Astronomers believe this means that the universe expansion is accelerating up. In this paper it is argued that if the ionized gas in the universe space is taken into account, then the brightness of the high redshift supernova Ia should be fainter than expected. The universe expansion does not need to be accelerating up. The exotic form of energy (dark energy) does not need to be introduce

  9. RELATIVE EFFICACY OF HUMAN SOCIAL INTERACTION AND FOOD AS REINFORCERS FOR DOMESTIC DOGS AND HAND-REARED WOLVES

    Science.gov (United States)

    Feuerbacher, Erica N; Wynne, Clive D. L

    2012-01-01

    Despite the intimate relationship dogs share with humans in Western society, we know relatively little about the variables that produce and maintain dog social behavior towards humans. One possibility is that human social interaction is itself a reinforcer for dog behavior. As an initial assessment of the variables that might maintain dog social behavior, we compared the relative efficacy of brief human social interaction to a small piece of food as a reinforcer for an arbitrary response (nose touch). We investigated this in three populations of canids: shelter dogs, owned dogs, and hand-reared wolves. Across all three canid populations, brief social interaction was a relatively ineffective reinforcer compared to food for most canids, producing lower responding and longer latencies than food. PMID:22851794

  10. Optical study of the DAFT/FADA galaxy cluster survey

    Science.gov (United States)

    Martinet, N.; Durret, F.; Clowe, D.; Adami, C.

    2013-11-01

    DAFT/FADA (Dark energy American French Team) is a large survey of ˜90 high redshift (0.42×10^{14} M_{⊙}) clusters with HST weak lensing oriented data, plus BVRIZJ 4m ground based follow up to compute photometric redshifts. The main goals of this survey are to constrain dark energy parameters using weak lensing tomography and to study a large homogeneous sample of high redshift massive clusters. We will briefly review the latest results of this optical survey, focusing on two ongoing works: the calculation of galaxy luminosity functions from photometric redshift catalogs and the weak lensing analysis of ground based data.

  11. Determining Central Black Hole Masses in Distant Active Galaxies

    DEFF Research Database (Denmark)

    Vestergaard, Marianne

    2002-01-01

    An empirical relationship, of particular interest for studies of high redshift active galactic nuclei (AGNs) and quasars, between the masses of their central black-holes and rest-frame ultraviolet (UV) parameters measured in single-epoch AGN spectra is presented. This relationship is calibrated...... black-hole demographics at high redshift as well as to statistically study the fundamental properties of AGNs. The broad line region size - luminosity relationship is key to the calibrations presented here. The fact that its intrinsic scatter is also the main source of uncertainty in the calibrations...

  12. Reionization Science Projections with the EXIST High-z GRB Sample

    Science.gov (United States)

    McQuinn, Matthew; EXIST Science Team

    2010-01-01

    The first structures in the Universe formed at z>7, at higher redshift than all currently known galaxies. Since GRBs are brighter than other cosmological sources at high redshift and exhibit simple power-law afterglow spectra that is ideal for absorption studies, they serve as powerful tools for studying the early universe. New facilities, in particular the EXIST Mission, planned for the coming decade will be able to obtain a large sample of high-redshift GRBs. Such a sample would constrain the nature of the first stars, galaxies, and the reionization history of the Universe.

  13. Cosmic Magnetization: From Spontaneously Emitted Aperiodic Turbulent to Ordered Equipartition Fields

    Science.gov (United States)

    Schlickeiser, R.

    2012-12-01

    It is shown that an unmagnetized nonrelativistic thermal electron-proton plasma spontaneously emits aperiodic turbulent magnetic field fluctuations of strength |δB|=3.5βeg1/3We1/2G, where βe is the normalized thermal electron temperature, We the thermal plasma energy density, and g the plasma parameter. For the unmagnetized intergalactic medium, immediately after the reionization onset, the field strengths from this mechanism are about 2×10-16G in cosmic voids and 2×10-10G in protogalaxies, both too weak to affect the dynamics of the plasma. Accounting for simultaneous viscous damping reduces these estimates to 2×10-21G in cosmic voids and 2×10-12G in protogalaxies. The shear and/or compression of the intergalactic and protogalactic medium exerted by the first supernova explosions locally amplify these seed fields and make them anisotropic, until the magnetic restoring forces affect the gas dynamics at ordered plasma betas near unity.

  14. Falsification of Dark Energy by Fluid Mechanics

    Science.gov (United States)

    Gibson, Carl H.

    2012-03-01

    The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating super- novae dimness, suggesting a remarkable reversal in the expansion rate of the Universe from a decrease to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanics and Herschel- Planck-Spitzer-Hubble etc. space telescope observations falsify both the accelerating ex- pansion rate and dark energy concepts. Kinematic viscosity is neglected in models of self-gravitational structure formation. Large plasma photon viscosity predicts protosu- perclustervoid fragmentation early in the plasma epoch and protogalaxies at the end. At the plasma-gas transition, the gas protogalaxies fragment into Earth-mass rogue plan- ets in highly persistent, trillion-planet clumps (proto-globular-star-cluster PGCs). PGC planets freeze to form the dark matter of galaxies and merge to form their stars, giving the hydrogen triple-point (14 K) infrared emissions observed. Dark energy is a system- atic dimming error for Supernovae Ia caused by partially evaporated planets feeding hot white dwarf stars at the Chandrasekhar carbon limit. Planet atmospheres may or may not dim light from SNe-Ia events depending on the line of sight.

  15. Direct formation of supermassive black holes via multi-scale gas inflows in galaxy mergers.

    Science.gov (United States)

    Mayer, L; Kazantzidis, S; Escala, A; Callegari, S

    2010-08-26

    Observations of distant quasars indicate that supermassive black holes of billions of solar masses already existed less than a billion years after the Big Bang. Models in which the 'seeds' of such black holes form by the collapse of primordial metal-free stars cannot explain the rapid appearance of these supermassive black holes because gas accretion is not sufficiently efficient. Alternatively, these black holes may form by direct collapse of gas within isolated protogalaxies, but current models require idealized conditions, such as metal-free gas, to prevent cooling and star formation from consuming the gas reservoir. Here we report simulations showing that mergers between massive protogalaxies naturally produce the conditions for direct collapse into a supermassive black hole with no need to suppress cooling and star formation. Merger-driven gas inflows give rise to an unstable, massive nuclear gas disk of a few billion solar masses, which funnels more than 10(8) solar masses of gas to a sub-parsec-scale gas cloud in only 100,000 years. The cloud undergoes gravitational collapse, which eventually leads to the formation of a massive black hole. The black hole can subsequently grow to a billion solar masses on timescales of about 10(8) years by accreting gas from the surrounding disk.

  16. VizieR Online Data Catalog: LBDS-Lynx region GMRT 150-MHz obs. (Ishwara-Chandra+, 2010)

    Science.gov (United States)

    Ishwara-Chandra, C. H.; Sirothia, S. K.; Wadadekar, Y.; Pal, S.; Windhorst, R.

    2011-08-01

    It has been known for nearly three decades that high-redshift radio galaxies exhibit steep radio spectra, and hence ultrasteep spectrum radio sources provide candidates for high-redshift radio galaxies. Nearly all radio galaxies with z>3 have been found using this redshift-spectral index correlation. We have started a programme with the Giant Metrewave Radio Telescope (GMRT) to exploit this correlation at flux density levels about 10 to 100 times deeper than the known high-redshift radio galaxies which were identified primarily using the already available radio catalogues. In our programme, we have obtained deep, high-resolution radio observations at 150MHz with GMRT for several "deep" fields which are well studied at higher radio frequencies and in other bands of the electromagnetic spectrum, with an aim to detect candidate high-redshift radio galaxies. In this paper we present results from the deep 150-MHz observations of the LBDS-Lynx field (Leiden-Berkeley Deep Survey), which has been already imaged at 327, 610 and 1412MHz with the Westerbork Synthesis Radio Telescope and at 1400 and 4860MHz with the Very Large Array. (2 data files).

  17. Lyα Forest Tomography from Background Galaxies: The First Megaparsec-resolution Large-scale Structure Map at z > 2

    NARCIS (Netherlands)

    Lee, Khee-Gan; Hennawi, Joseph F.; Stark, Casey; Prochaska, J. Xavier; White, Martin; Schlegel, David J.; Eilers, Anna-Christina; Arinyo-i-Prats, Andreu; Suzuki, Nao; Croft, Rupert A. C.; Caputi, Karina I.; Cassata, Paolo; Ilbert, Olivier; Garilli, Bianca; Koekemoer, Anton M.; Le Brun, Vincent; Le Fèvre, Olivier; Maccagni, Dario; Nugent, Peter; Taniguchi, Yoshiaki; Tasca, Lidia A. M.; Tresse, Laurence; Zamorani, Gianni; Zucca, Elena

    2014-01-01

    We present the first observations of foreground Lyα forest absorption from high-redshift galaxies, targeting 24 star-forming galaxies (SFGs) with z ~ 2.3-2.8 within a 5' × 14' region of the COSMOS field. The transverse sightline separation is ~2 h -1 Mpc comoving, allowing us to create a tomographic

  18. A Strongly Lensed Massive Ultracompact Quiescent Galaxy at z ~ 2.4 in the COSMOS/UltraVISTA Field

    NARCIS (Netherlands)

    Muzzin, Adam; Labbe, Ivo; Franx, Marijn; van Dokkum, Pieter; Holt, J.; Szomoru, Daniel; van de Sande, Jesse; Brammer, Gabriel; Marchesini, Danilo; Stefanon, Mauro; Buitrago, F.; Caputi, K. I.; Dunlop, James; Fynbo, J. P. U.; Le Fevre, Olivier; McCracken, Henry J.; Milvang-Jensen, Bo

    2012-01-01

    We report the discovery of a massive ultracompact quiescent galaxy that has been strongly lensed into multiple images by a foreground galaxy at z = 0.960. This system was serendipitously discovered as a set of extremely K-s-bright high-redshift galaxies with red J - K-s colors using new data from

  19. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy. B. B. Nath. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 34 Review. From Nearby Low Luminosity AGN to High Redshift Radio Galaxies: Science Interests with Square Kilometre Array · P. Kharb D. V. Lal V. Singh J.

  20. Galaxy clusters as probes for cosmology and dark matter

    DEFF Research Database (Denmark)

    Battistelli, Elia S.; Burigana, Carlo; De Bernardis, Paolo

    2016-01-01

    In recent years, significant progress has been made in building new galaxy clusters samples, at low and high redshifts, from wide-area surveys, particularly exploiting the Sunyaev-Zel'dovich (SZ) effect. A large effort is underway to identify and characterize these new systems with optical/NIR an...

  1. EXTREMELY STRONG CARBON-MONOXIDE EMISSION FROM THE CLOVERLEAF QUASAR AT A REDSHIFT OF 2.5

    NARCIS (Netherlands)

    BARVAINIS, R; TACCONI, L; ANTONUCCI, R; ALLOIN, D; COLEMAN, P

    1994-01-01

    GALAXIES at high redshift are very faint and difficult to study at optical and near-infrared wavelengths, but detection of far-infrared emission(1) and molecular gas(2,3) in a galaxy at redshift z approximate to 2.3 has suggested that their early evolution may be investigated by these means instead.

  2. Lyman alpha emission from the first galaxies: implications of UV backgrounds and the formation of molecules : implications of UV backgrounds and the formation of molecules

    NARCIS (Netherlands)

    Latif, M. A.; Schleicher, D. R. G.; Spaans, M.; Zaroubi, S.

    The Lyman alpha line is a robust tracer of high redshift galaxies. We present estimates of Lyman alpha emission from a protogalactic halo illuminated by UV background radiation fields with various intensities. For this purpose, we performed cosmological hydrodynamics simulations with the adaptive

  3. Cosmological magnetic fields

    Indian Academy of Sciences (India)

    Magnetic fields are observed not only in stars, but in galaxies, clusters, and even high redshift Lyman- systems. In principle, these fields could play an important role in structure formation and also affect the anisotropies in the cosmic microwave background radiation (CMB). The study of cosmological magnetic fields aims ...

  4. The case for the cosmological constant

    Indian Academy of Sciences (India)

    I present a short overview of current observational results and theoretical models for a cosmological constant. The main motivation for invoking a small cosmological constant (or -term) at the present epoch has to do with observations of high redshift Type Ia supernovae which suggest an accelerating universe.

  5. Anisotropic Bianchi-I universe with phantom field and cosmological ...

    Indian Academy of Sciences (India)

    of the cosmological solutions. Keywords. Anisotropic cosmology; phantom field; accelerating universe. PACS Nos 04.20.Jb; 98.80.Cq. 1. Introduction. Recent astrophysical data obtained from high redshift surveys of Supernovae,. COBE to WMAP predict that the present universe is passing through an accel- erating phase of ...

  6. The case for the cosmological constant

    Indian Academy of Sciences (India)

    Abstract. I present a short overview of current observational results and theoretical models for a cosmological constant. The main motivation for invoking a small cosmological constant (orA-term) at the present epoch has to do with observations of high redshift Type Ia supernovae which suggest an accelerating universe.

  7. Role of primordial black holes in the direct collapse scenario of ...

    Indian Academy of Sciences (India)

    In this paper, we explore the possibility of accreting primordial black holes as the source of heating for the collapsing gas in the context of the direct collapse black hole scenario for the formation of super-massive black holes (SMBHs) at high redshifts, z ∼ 6 – 7 . One of the essential requirements for the direct collapse model ...

  8. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    High-Redshift Radio Galaxies from Deep Fields · C. H. Ishwara-Chandra S. K. Sirothia ... 4 December 2011 pp 613-614. Deep GMRT 150 MHz Observations of the DEEP2 Fields: Searching for High Red-Shift Radio Galaxies Revisited ... Articles are also visible in Web of Science immediately. All these have helped shorten ...

  9. Fueling the central engine of radio galaxies. II. The footprints of AGN feedback on the ISM of 3C 236

    NARCIS (Netherlands)

    Labiano, A.; Garcia-Burillo, S.; Combes, F.; Usero, A.; Soria-Ruiz, R.; Tremblay, G.; Neri, R.; Fuente, A.; Morganti, R.; Oosterloo, T.

    Context. There is growing observational evidence of active galactic nuclei (AGN) feedback on the interstellar medium (ISM) of radio-quiet and radio-loud galaxies. While AGN feedback is expected to be more common at high-redshift objects, studying local universe galaxies helps to better characterize

  10. The optical afterglow and host galaxy of GRB 000926

    DEFF Research Database (Denmark)

    Fynbo, J.U.; Gorosabel, J.; Dall, T.H.

    2002-01-01

    In this paper we illustrate with the case of GRB 000926 how Gamma Ray Bursts (GRBs) can be used as cosmological lighthouses to identify and study star forming galaxies at high redshifts. The optical afterglow of the burst was located with optical imaging at the Nordic Optical Telescope 20.7 hours...

  11. C IV LINE-WIDTH ANOMALIES

    DEFF Research Database (Denmark)

    Denney, Kelly Dianne; Pogge, R.W.; Assef, R.J.

    2013-01-01

    Comparison of six high-redshift quasar spectra obtained with the Large Binocular Telescope with previous observations from the Sloan Digital Sky Survey shows that failure to correctly identify absorption and other problems with accurate characterization of the CIV emission line profile in low S/N...

  12. Review FRB Event Rate Predictions for the Ooty Wide Field Array

    Indian Academy of Sciences (India)

    ing models, (b) the minimum total energy required to detect events, (c) the redshift distribution and (d) the detection rates of FRBs for the ... the scattering model I and remain flat and extend up to high redshifts (z ≲ 5) for the scattering model II. Keywords. ... FRBs often show ∼5−20 times excess DMs compared to what is ...

  13. Tracking the Shadows through GMRT

    Indian Academy of Sciences (India)

    The structures of faint high redshift galaxies cannot be observed directly. But if a luminous quasar is located farther along their line of sight, high resolution absorption lines offer a valuable and reliable probe to their structure. GMRT is suited to monitor the absorption spectra, if the redshifted neutral hydrogen or OH doublet ...

  14. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... 2011 pp 609-612. High-Redshift Radio Galaxies from Deep Fields ... Deep GMRT 150 MHz Observations of the DEEP2 Fields: Searching for High Red-Shift Radio Galaxies Revisited ... Articles are also visible in Web of Science immediately.

  15. How do galaxies Accrete Gas and Form Stars?

    NARCIS (Netherlands)

    Putman, M E; Henning, P; Bolatto, A; Keres, D; Pisano, D J; Rosenberg, J; Bigiel, F; Bryan, G; Calzetti, D; Carilli, C; et al., [No Value

    2009-01-01

    from their initial dark matter seeds to the complex structures we observe at z = 0. The role of mergers has been documented through both observations and simulations, numerous satellites that may represent these initial dark matter seeds have been discovered in the Local Group, high redshift

  16. A young star-forming galaxy at z = 3.5 with an extended Ly\\,$α$ halo seen with MUSE

    DEFF Research Database (Denmark)

    Patrício, Vera; Richard, Johan; Verhamme, Anne

    2016-01-01

    Spatially resolved studies of high redshift galaxies, an essential insight into galaxy formation processes, have been mostly limited to stacking or unusually bright objects. We present here the study of a typical (L$^{*}$, M$_\\star$ = 6 $\\times 10^9$ $M_\\odot$) young lensed galaxy at $z=3...

  17. Songlines from Direct Collapse Seed Black Holes

    NARCIS (Netherlands)

    Aykutalp, Aycin; Wise, John; Spaans, Marco; Meijerink, Rowin

    In the last decade, the growth of supermassive black holes (SMBHs) has been intricately linked to galaxy formation and evolution, and is a key ingredient in the assembly of galaxies. Observations of SMBHs with masses of 109 solar at high redshifts (z~7) poses challenges to the theory of seed black

  18. On the (Non-)Enhancement of the Lyα Equivalent Width by a Multiphase Interstellar Medium

    DEFF Research Database (Denmark)

    Laursen, Peter; Duval, F.; Östlin, G.

    2013-01-01

    It has been suggested that radiative transfer effects may explain the unusually high equivalent widths (EWs) of the Lya line, observed occasionally from starburst galaxies, especially at high redshifts. If the dust is locked up inside high-density clouds dispersed in an empty intercloud medium, t...

  19. Do Unification Models Explain the X-ray Properties of Radio Sources?

    NARCIS (Netherlands)

    Wilkes, Belinda J.; Kuraszkiewicz, J.; Haas, M.; Barthel, P.; Willner, S. P.; Leipski, C.; Worrall, D.; Birkinshaw, M.; Antonucci, R. R.; Ashby, M.; Chini, R.; Fazio, G. G.; Lawrence, C. R.; Ogle, P. M.; Schulz, B.

    Chandra observations of a complete, flux-limited sample of 38 high-redshift (1

  20. Feedback and the structure of simulated galaxies at redshift z=2

    NARCIS (Netherlands)

    Sales, Laura V.; Navarro, Julio F.; Schaye, Joop; Dalla Vecchia, Claudio; Springel, Volker; Booth, C. M.

    2010-01-01

    We study the properties of simulated high-redshift galaxies using cosmological N-body/gasdynamical runs from the OverWhelmingly Large Simulations (OWLS) project. The runs contrast several feedback implementations of varying effectiveness: from no feedback, to supernova-driven winds to powerful

  1. Phenomenology of a realistic accelerating universe using tracker fields

    Indian Academy of Sciences (India)

    pansion was understood to be slowing down; consequently the Einstein–de Sitter model was taken to be the standard model of the observable universe. However, recent studies undertaken by the Supernova Cosmology Project Team [1] and the High Redshift Search. Team [2] reveal that the distant supernovae are fainter ...

  2. Elemental Abundances in the Broad Emission Line Region of Quasars at Redshifts larger than 4

    DEFF Research Database (Denmark)

    Dietrich, M.; Appenzeller, I.; Hamann, F.

    2003-01-01

    We present observations of 11 high redshift quasars ($3.9 \\la z \\la 5.0$) observed with low spectral resolution in the restframe ultraviolet using FORS 1 at the VLT UT 1. The emission-line fluxes of strong permitted and intercombination ultraviolet emission lines are measured to estimate the chem...

  3. Simulating the 21 cm forest detectable with LOFAR and SKA in the spectra of high-z GRBs

    NARCIS (Netherlands)

    Ciardi, B.; Inoue, S.; Abdalla, F. B.; Asad, K.; Bernardi, G.; Bolton, J. S.; Brentjens, M.; de Bruyn, A. G.; Chapman, E.; Daiboo, S.; Fernandez, E. R.; Ghosh, A.; Graziani, L.; Harker, G. J. A.; Iliev, I. T.; Jelić, V.; Jensen, H.; Kazemi, S.; Koopmans, L. V. E.; Martinez, O.; Maselli, A.; Mellema, G.; Offringa, A. R.; Pandey, V. N.; Schaye, J.; Thomas, R.; Vedantham, H.; Yatawatta, S.; Zaroubi, S.

    2015-01-01

    We investigate the feasibility of detecting 21 cm absorption features in the afterglow spectra of high redshift long Gamma Ray Bursts (GRBs). This is done employing simulations of cosmic reionization, together with estimates of the GRB radio afterglow flux and the instrumental characteristics of the

  4. CI, [CII] and CO observations towards TNJ 1338–1942: Probing the ISM in a massive proto-cluster galaxy at z = 4.11

    DEFF Research Database (Denmark)

    König, S; Greve, T R; Seymour, N

    2012-01-01

    A number of studies have dealt with the link between distant powerful radio sources and the most massive galaxies in the early Universe. Despite major advances in our understanding of high redshift radio galaxies (HzRGs), we still only have a rudimentary picture of the physical conditions (i.e. gas...

  5. Is cold gas fuelling the radio galaxy NGC 315?

    NARCIS (Netherlands)

    Morganti, R.; Peck, A. B.; Oosterloo, T. A.; van Moorsel, G.; Capetti, A.; Fanti, R.; Parma, P.; Ruiter de, H.R.

    2009-01-01

    We present WSRT, VLA and VLBI observations of the Hi absorption in the radio galaxy NGC 315. The main result is that two Hi absorbing systems are detected against the central region. In addition to the known highly redshifted, very narrow component, we detect relatively broad (FWZI similar to 150 km

  6. Fulltext PDF

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    increases from Madau-type profiles to those with additional star formation at high redshifts, the numbers for the Peak-M profile being in best agreement with Bran01. Now, a most recent development in SFR research has been the study of star-formation histories of individual galaxies and various galaxy-types. SFR profiles of ...

  7. Three types of galaxy disks

    NARCIS (Netherlands)

    Pohlen, M.; Erwin, P.; Trujillo, I.; Beckman, J. E.; Knapen, JH; Mahoney, TJ; Vazdekis, A

    2008-01-01

    We present our new scheme for the classification of radial stellar surface brightness profiles for disk galaxies. We summarize the current theoretical attempts to understand their origin and give an example of an application by comparing local galaxies with their counterparts at high redshift (z

  8. CLASS B 1359 + 154: Modelling Lensing by a Group of Galaxies

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Both models call for, in addition to non-singular galaxy-type lenses, a larger scale mass component that resembles the extended dark matter distributions seen in relatively low-redshift galaxy groups. It is presently observationally impossible to study the extended X-ray emission from a group at such a high redshift, hence ...

  9. CLASS B 1359+ 154: Modelling Lensing by a Group of Galaxies

    Indian Academy of Sciences (India)

    Both models call for, in addition to non-singular galaxy-type lenses, a larger scale mass component that resembles the extended dark matter distributions seen in relatively low-redshift galaxy groups. It is presently observationally impossible to study the extended X-ray emission from a group at such a high redshift, hence ...

  10. The radio spectral energy distribution of infrared-faint radio sources

    NARCIS (Netherlands)

    Herzog, A.; Norris, R. P.; Middelberg, E.; Seymour, N.; Spitler, L. R.; Emonts, B. H. C.; Franzen, T. M. O.; Hunstead, R.; Intema, H. T.; Marvil, J.; Parker, Q. A.; Sirothia, S. K.; Hurley-Walker, N.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Callingham, J. R.; Deshpande, A. A.; Dwarakanath, K. S.; For, B. -Q; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hindson, L.; Johnston-Hollitt, M.; Kapińska, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Oberoi, D.; Offringa, A.; Ord, S. M.; Prabu, T.; Procopio, P.; Udaya Shankar, N.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q.; Bannister, K. W.; Chippendale, A. P.; Harvey-Smith, L.; Heywood, I.; Indermuehle, B.; Popping, A.; Sault, R. J.; Whiting, M. T.

    2016-01-01

    Context. Infrared-faint radio sources (IFRS) are a class of radio-loud (RL) active galactic nuclei (AGN) at high redshifts (z ≥ 1.7) that are characterised by their relative infrared faintness, resulting in enormous radio-to-infrared flux density ratios of up to several thousand. Aims: Because of

  11. Planck 2013 results. XVIII. The gravitational lensing-infrared background correlation

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.

    2013-01-01

    of these two unique probes allows us to measure directly the connection between dark and luminous matter in the high redshift (1 = 1. We measure directly the SFR density with around 2 sigma significance for three redshift bins between z = 1 and 7, thus opening a new window into the study of the formation...

  12. Lyman alpha emission from the first galaxies : Implications of UV backgrounds and the formation of molecules

    NARCIS (Netherlands)

    Latif, M. A.; Schleicher, D. R. G.; Spaans, Maarten; Zaroubi, S.

    The Lyman alpha line is a robust tracer of high redshift galaxies. We present estimates of Lyman alpha emission from a protogalactic halo illuminated by UV background radiation fields with various intensities. For this purpose, we performed cosmological hydrodynamics simulations with the adaptive

  13. Genome Sequence of Canine Adenovirus Type 1 Isolated from a Wolf (Canis lupus) in Southern Italy.

    Science.gov (United States)

    Pizzurro, Federica; Marcacci, Maurilia; Zaccaria, Guendalina; Orsini, Massimiliano; Cito, Francesca; Rosamilia, Alfonso; Di Renzo, Ludovica; Malatesta, Daniela; Di Sabatino, Daria; Lorusso, Alessio

    2017-04-20

    Canine adenovirus type 1 (CAdV-1), a DNA virus of the family Adenoviridae, causes infectious canine hepatitis, a highly contagious disease primarily affecting canids. In this report, we describe the isolation and whole-genome sequence of a CAdV-1 isolate from the liver of a free-ranging wolf (Canis lupus). Copyright © 2017 Pizzurro et al.

  14. Clinical, Laboratory Diagnosis and Treatment of Ehrlichial Infections ...

    African Journals Online (AJOL)

    Canine ehrlichiosis, a tick borne disease, is caused by an intracellular bacteria belonging to the genus Ehrlichia. It is one of the most important diseases in dogs and other canids in tropical and subtropical regions. The disease is transmitted transstadially, mainly, by the nymph and adult stages of the brown dog tick, ...

  15. Oslerus osleri (metastrongyloidea; filaroididae) in gray wolves (Canis lupus) from Banff National Park, Alberta, Canada.

    Science.gov (United States)

    Verocai, Guilherme G; Schock, Danna M; Lejeune, Manigandan; Warren, Amy L; Duignan, Pádraig J; Kutz, Susan J

    2013-04-01

    Oslerus osleri is a filaroid parasite of the respiratory tract of canids. In North America, it is most commonly reported from coyotes (Canis latrans) and domestic dogs (Canis lupus familiaris), but reports in gray wolves (Canis lupus) are infrequent. We report a new geographic record for O. osleri in four gray wolves from Banff National Park, Alberta, Canada. Adult nematodes found in nodules in the submucosa of the trachea and bronchi were identified as O. osleri based on morphometry of spicules of males. We sequenced two segments of the genome of adult nematodes: a 1,111-base pair (bp) segment of the 18S region that was 100% identical to the 18S region of O. osleri from a coyote in California and a 537-bp segment that included the ITS-2 region and partial 5.8S and 28S genes. Histopathologically, there were submucosal nodules of adult nematodes surrounded by fibrosis and lymphoplasmacytic inflammation. These findings are consistent with O. osleri infections in other canids. The importance of this parasite in wild canid populations is unknown, but prevalence may be underestimated because many studies have focused on gastrointestinal parasites or used routine fecal flotation that has low sensitivity for this parasite. The ecology and population genetics of this parasite where multiple species of canids are sympatric warrant closer investigation to determine potential for interspecies transmission.

  16. A phylogenetic analysis of basal metabolism, total evaporative water loss, and life-history among foxes from desert and mesic regions

    NARCIS (Netherlands)

    Williams, JB; Munoz-Garcia, A; Ostrowski, S; Tieleman, BI

    We measured basal metabolic rate (BMR) and total evaporative water loss (TEWL) of species of foxes that exist on the Arabian Peninsula, Blanford's fox (Vulpes cana) and two subspecies of Red fox (Vulpes vulpes). Combining these data with that on other canids from the literature, we searched for

  17. Abdominal Cysticercosis in a Red Fox ( Vulpes vulpes ).

    Science.gov (United States)

    Whipp, Christopher James; Daoust, Pierre-Yves; Conboy, Gary; Gelens, Hans

    2017-01-01

    A large abdominal mass containing numerous cysticerci identified as those of Taenia crassiceps (=Cysticercus longicollis) was found in the pelvic region of the abdominal cavity of a severely constipated and emaciated red fox ( Vulpes vulpes ) in Prince Edward Island, Canada. Cysticercosis has not previously been reported in a wild canid in North America.

  18. Differential effects of coyotes and red foxes on duck nest success

    Science.gov (United States)

    Sovada, Marsha A.; Sargeant, A.; Grier, J.W.

    1995-01-01

    Low recruitment rates prevail among ducks in the Prairie Pothole Region of North America, primarily because of high nest depredation rates. The red fox (Vulpes vulpes) is a major predator of duck eggs, but fox abundance is depressed by coyotes (Canis latrans). We tested the hypothesis that nest success of upland-nesting ducks is higher in areas with coyotes than in areas with red foxes. We conducted the study during 1990-92 in uplands of 36 areas managed for nesting ducks in North Dakota and South Dakota. Overall nest success averaged 32% (95% CI = 25-40) on 17 study areas where coyotes were the principal canid and 17% (CI = 11-25) on 13 study areas where red foxes were the principal canid (P = 0.01). Both canids were common on 6 other areas, where nest success averaged 25% (CI = 13-47). Habitat composition, predator communities with the exception of canids, and species composition of duck nests in coyote and red fox areas were similar overall. Upon examining only nests with greater than or equal to 6 eggs on the last visit prior to hatch or depredation, we determined nests with evidence characteristic of fox predation accounted for 4% of depredated nests in coyote areas and 27% in fox areas (P = 0.001). An expanding coyote population is contributing to higher overall nest success. Management of coyotes may be an effective method for increasing duck nest success.

  19. Regurgitative food transfer among wild wolves

    Science.gov (United States)

    L. David Mech; Paul C. Wolf; Jane M. Packard

    1999-01-01

    Few studies of monogamous canids have addressed regurgitation in the context of extended parental care and alloparental care within family groups. We studied food transfer by regurgitation in a pack of wolves on Ellesmere Island, North West Territories, Canada, during 6 summers from 1988 through 1996. All adult wolves, including yearlings and a post-reproductive female...

  20. Serological survey of diseases of free-ranging gray wolves (Canis lupus) in Minnesota

    Science.gov (United States)

    We tested serologic samples from 387 free-ranging wolves (Canis lupus) from 2007–2013 for exposure to 8 canid pathogens to establish baseline data on disease prevalence and spatial distribution in Minnesota’s wolf population. We found high exposure to canine adenovirus 1 and 2 (88% adults, 45% pups...

  1. Steel-Jawed Leghold Traps and Killing Neck Snares: Similar Injuries Command Change to Agreement on International Humane Trapping Standards.

    Science.gov (United States)

    Proulx, Gilbert; Rodtka, Dwight

    2017-01-01

    According to the Agreement on International Humane Trapping Standards (AIHTS), which was signed by the European Community, Canada, and Russia in 1997, killing devices used for the capture of canids and other fur-bearing nonhuman animals should render an animal irreversibly unconscious within 300 s. However, killing neck snares are not included in the agreement. In this commentary, a parallel is drawn between injuries caused by steel-jawed leghold traps, which have been banned by the AIHTS signatory countries, and killing neck snares to demonstrate that these snares should also be included in international humane trapping standards (i.e., AIHTS). Previous scientific investigations have shown that neither manual nor power-killing neck snares can consistently render canids unconscious rapidly. Animals caught in killing neck snares suffer injuries that are similar to or worse than those reported for leg-captured canids. The authors strongly recommend that AIHTS be modified to include killing neck snares and that such devices be subject to the criteria applied to other trapping devices. Alternative restraining trapping devices, which are effective and more humane, are available for capturing wild canids.

  2. Dominance in domestic dogs revisited: Useful habit and useful construct?

    NARCIS (Netherlands)

    Schilder, M.B.H.; Vinke, C.M.; Borg, van der J.A.M.

    2014-01-01

    In the last decade, the validity and relevance of the dominance model was regularly put into question regarding relationships between canids like dogs and wolves, and consequently, humanedog relationships as well. The concept underlying this model, scientifically defined as an intervening variable

  3. Seasonal food habits of the coyote in the South Carolina coastal plain

    Science.gov (United States)

    Joshua D. Schrecengost; John C. Kilgo; David Mallard; H. Scott Ray; Karl V. Miller

    2008-01-01

    Spatial and temporal plasticity in Canis latrans (coyote) diets require regional studies to understand the ecological role of this omnivorous canid. Because coyotes have recently become established in South Carolina, we investigated their food habits by collecting 415 coyote scats on the Savannah River Site in western South Carolina from May 2005?...

  4. Seroprevalence of Neospora caninum in feral swine (Sus scrofa) in the United States

    Science.gov (United States)

    The protozoon Neospora caninum is a major cause of abortion in cattle worldwide. Canids (Canis familiaris, Canis latrans, Canis lupus) are its definitive hosts whereas many other animal species, including pigs are intermediate hosts for the parasite. Feral swine may serve as sentinels for the parasi...

  5. Molecules and beyond: Assessing the distinctness of the Great Lakes wolf

    Science.gov (United States)

    Michael K. Schwartz; John A. Vucetich

    2009-01-01

    The dog family, Canidae, is a widely distributed group of species that have evolved and radiated relatively recently into 16 genera and 36 recognized species (Nowak 1999). Specific taxonomic designations for some canid taxa can be unclear due to frequent interspecific hybridization among species in both historical and contemporary times, and our imperfect...

  6. A specimen of Canis cf. C. etruscus (Mammalia, Carnivora) from the Middle Villafranchian of the Oosterschelde

    NARCIS (Netherlands)

    Reumer, J.W.F.; Piskoulis, P.

    A recent find of a Middle Villafranchian (c. 2.35–2.10 Ma) Canis cf. C. etruscus in the trawlings from the Oosterschelde concerns the oldest dog known from the Netherlands and is the first appearance record of this canid in the North Sea Basin. It shows that the tribe Canini was dispersed beyond

  7. All about neosporosis in Brazil

    Science.gov (United States)

    Neospora caninum is a protozoan parasite with canids as the definitive hosts and many warm blooded animals as intermediate hosts. Until late 1988, it was misdiagnosed as Toxoplasma gondii when it was named and distinguished from T. gondii. Although these parasites are structurally similar they are b...

  8. Neospora caninum surface antigen (p40) is a potential diagnostic marker for cattle neosporosis

    Science.gov (United States)

    Neospora caninum is an intracellular protozoan that infects domestic and wild canids as well as many warm-blooded animals as shown by the isolation of viable parasites. The effectiveness of diagnostic tests for detecting specific antibodies against N. caninum is hampered by potential cross-reaction ...

  9. Isolation of viable neospora caninum from brains of wild gray wolves (canis lupus)

    Science.gov (United States)

    Neospora caninum is a common cause of abortion in cattle worldwide. Canids, including the dog and the dingo (Canis familiaris), the coyote (Canis latrans), and the gray wolf (Canis lupus) are its definitive hosts, but also can act as intermediate hosts by harbor tissue stages of the parasite that ca...

  10. Intestinal rupture in a Mexican gray wolf (Canis lupus baileyi) in association with ingestion of a diazinon-impregnated cattle ear tag.

    Science.gov (United States)

    Kagan, Rebecca

    2013-01-01

    A free-ranging Mexican gray wolf (Canis lupus baileyi) suffered intestinal rupture following ingestion of an insecticidal cattle ear tag. Subsequent organophosphate toxicosis as a cause of the rupture was speculated. Insecticidal ear tags could represent a poisoning risk in canids and other wildlife scavengers.

  11. Hypersonic cruise aircraft propulsion integration study, volume 2

    Science.gov (United States)

    Morris, R. E.; Brewer, G. D.

    1979-01-01

    Conceptual vehicle configuration and propulsion approach for a Mach 6 transport aircraft capable of carring 200 passengers 9260 km was investigated. Wind tunnel test data for various hypersonic transport configurations were examined. Canidates for baseline reference vehicles were selected. An explanation of technical methods which were used and configuration details which were significant in the final vehicle concept are given.

  12. The first wolf found in the Netherlands in 150 years was the victim of a wildlife crime

    NARCIS (Netherlands)

    Gravendeel, B.; Groot, de G.A.; Kik, M.; Beentjes, K.; Bergman, H.; Caniglia, R.; Cremers, H.; Fabbri, E.; Groenenberg, D.; Grone, A.; Groot Bruinderink, G.W.T.A.; Font, I.; Hakhof, J.; Harms, V.; Jansman, H.A.H.; Janssen, R.; Lammertsma, D.R.; Laros, I.; Linnartz, L.; Marel, van der D.; Mulder, J.L.; Mije, van der S.; Nieman, A.M.; Nowak, C.; Randi, E.; Rijks, M.; Speksnijder, A.; Vonhof, H.B.

    2013-01-01

    On July 4th 2013 a dead subadult female wolf-like canid was found by the roadside between Luttelgeest and Marknesse in the Noordoostpolder in the central part of the Netherlands. As the last observations of wild wolves in the Netherlands date back to 1869 the discovery of this animal generated a lot

  13. Dwarf Galaxies from Deep Fields to the Near Field

    Science.gov (United States)

    Boylan-Kolchin, Michael

    2017-08-01

    We propose to use cosmological hydrodynamical simulations - both zoom-in and large-volume - to study the connections between the faintest observable galaxies in the high-redshift Universe and dwarf galaxies locally.Studies of the likely descendants of very faint HUDF / Frontier Field galaxies will provide a powerful complement to direct observations at z 8 for investigating the physical processes in the high-redshift Universe and, in connection with properties of low-mass galaxies in the nearby Universe, will produce strong constraints on reionization scenarios and dark matter models. Understanding the relationship between high-redshift and local galaxy populations through simulations requires an accurate knowledge of the links between galaxy populations at cosmic dawn and those locally. All existing results on this topic either suffer from poor statistics or are unable to resolve the hosts of Frontier Field galaxies, however. Our program will address this shortcoming by combining a series of zoom-in hydrodynamical simulations with the next generation of large-volume hydrodynamical simulations of the galaxy population from the Illustris project.HST has made unique and invaluable contributions to surveys of galaxies at high redshifts and to detailed, resolved-star studies of individual galaxies in the very nearby Universe. Our study will help cement links between these two HST legacies. We will quantify the relationships between faint populations at low and high redshifts, characterize the merger histories of dwarf galaxies (both forward and backward in time), and test the validity of various popular models such as abundance matching based on UV luminosity functions.

  14. A model for the origin of bursty star formation in galaxies

    Science.gov (United States)

    Faucher-Giguère, Claude-André

    2018-01-01

    We propose a simple analytic model to understand when star formation is time steady versus bursty in galaxies. Recent models explain the observed Kennicutt-Schmidt relation between star formation rate and gas surface densities in galaxies as resulting from a balance between stellar feedback and gravity. We argue that bursty star formation occurs when such an equilibrium cannot be stably sustained, and identify two regimes in which galaxy-scale star formation should be bursty: (i) at high redshift (z ≳ 1) for galaxies of all masses, and (ii) at low masses (depending on gas fraction) for galaxies at any redshift. At high redshift, characteristic galactic dynamical time-scales become too short for supernova feedback to effectively respond to gravitational collapse in galactic discs (an effect recently identified for galactic nuclei), whereas in dwarf galaxies star formation occurs in too few bright star-forming regions to effectively average out. Burstiness is also enhanced at high redshift owing to elevated gas fractions in the early Universe. Our model can thus explain the bursty star formation rates predicted in these regimes by recent high-resolution galaxy formation simulations, as well as the bursty star formation histories observationally inferred in both local dwarf and high-redshift galaxies. In our model, bursty star formation is associated with particularly strong spatiotemporal clustering of supernovae. Such clustering can promote the formation of galactic winds and our model may thus also explain the much higher wind mass loading factors inferred in high-redshift massive galaxies relative to their z ∼ 0 counterparts.

  15. Comparative molecular phylogeny and evolution of sex chromosome DNA sequences in the family Canidae (Mammalia: Carnivora).

    Science.gov (United States)

    Tsubouchi, Ayako; Fukui, Daisuke; Ueda, Miya; Tada, Kazumi; Toyoshima, Shouji; Takami, Kazutoshi; Tsujimoto, Tsunenori; Uraguchi, Kohji; Raichev, Evgeniy; Kaneko, Yayoi; Tsunoda, Hiroshi; Masuda, Ryuichi

    2012-03-01

    To investigate the molecular phylogeny and evolution of the family Canidae, nucleotide sequences of the zinc-finger-protein gene on the Y chromosome (ZFY, 924-1146 bp) and its homologous gene on the X chromosome (ZFX, 834-839 bp) for twelve canid species were determined. The phylogenetic relationships among species reconstructed by the paternal ZFY sequences closely agreed with those by mtDNA and autosomal DNA trees in previous reports, and strongly supported the phylogenetic affinity between the wolf-like canids clade and the South American canids clade. However, the branching order of some species differed between phylogenies of ZFY and ZFX genes: Cuon alpinus and Canis mesomelas were included in the wolf-like canid clades in the ZFY tree, whereas both species were clustered in a group of Chrysocyon brachyurus and Speothos venaticus in the ZFX tree. The topology difference between ZFY and ZFX trees may have resulted from the two-times higher substitution rate of the former than the latter, which was clarified in the present study. In addition, two types of transposable element sequence (SINE-I and SINE-II) were found to occur in the ZFY final intron of the twelve canid species examined. Because the SINE-I sequences were shared by all the species, they may have been inserted into the ZFY of the common ancestor before species radiation in Canidae. By contract, SINE-II found in only Canis aureus could have been inserted into ZFY independently after the speciation. The molecular diversity of SINE sequences of Canidae reflects evolutionary history of the species radiation.

  16. Falsification of dark energy by fluid mechanics

    CERN Document Server

    Gibson, Carl H

    2012-01-01

    The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating supernovae dimness, suggesting a remarkable change in the expansion rate of the Universe from a decrease since the big bang to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanical considerations falsify both the accelerating expansion and dark energy concepts. Kinematic viscosity is neglected in current standard models of self-gravitational structure formation, which rely on cold dark matter CDM condensations and clusterings that are also falsified by fluid mechanics. Weakly collisional CDM particles do not condense but diffuse away. Photon viscosity predicts superclustervoid fragmentation early in the plasma epoch and protogalaxies at the end. At the plasma-gas transition, the plasma fragments into Earth-mass gas planets in trillion planet clumps (proto-globular-star-cluster PGCs). The hydrogen planets freeze to form the dark matter of galaxies ...

  17. Fred Hoyle: contributions to the theory of galaxy formation

    Science.gov (United States)

    Efstathiou, George

    I review two fundamental contributions that Fred Hoyle made to the theory of galaxy formation. Hoyle was the first to propose that protogalaxies acquired their angular momentum via tidal torques from neighbouring perturbations during a period of gravitational instability. To my knowldege, he was also the first to suggest that the masses of galaxies could be explained by the requirement that primordial gas clouds cool radiatively on a suitable timescale. Tidal torques and cooling arguments play a central role in the modern theory of galaxy formation. It is a measure of Hoyle's breadth and inventiveness that he recognized the importance of these processes at such an early stage in the history of the subject.

  18. Magnetogenesis, spectator fields and CMB signatures

    Energy Technology Data Exchange (ETDEWEB)

    Giovannini, Massimo [Centro ' Enrico Fermi' , Compendio del Viminale, Via Panisperna 89/A, 00184 Rome (Italy); Department of Physics, Theory Division, CERN, 1211 Geneva 23 (Switzerland)], E-mail: massimo.giovannini@cern.ch

    2008-01-24

    A viable class of magnetogenesis models can be constructed by coupling the kinetic term of the hypercharge to a spectator field whose dynamics does not affect the inflationary evolution. The magnetic power spectrum is explicitly related to the power spectrum of (adiabatic) curvature inhomogeneities when the quasi-de Sitter stage of expansion is driven by a single scalar degree of freedom. Depending upon the value of the slow-roll parameters, the amplitude of smoothed magnetic fields over a (comoving) Mpc scale can be as large as 0.01-0.1 nG at the epoch of the gravitational collapse of the protogalaxy. The contributions of the magnetic fields to the Sachs-Wolfe plateau and to the temperature autocorrelations in the Doppler region compare favourably with the constraints imposed by galactic magnetogenesis. Stimulating lessons are drawn on the interplay between magnetogenesis models and their possible CMB signatures.

  19. Chemical evolution of star clusters.

    Science.gov (United States)

    van Loon, Jacco Th

    2010-02-28

    I discuss the chemical evolution of star clusters, with emphasis on old Galactic globular clusters (GCs), in relation to their formation histories. GCs are clearly formed in a complex fashion, under markedly different conditions from any younger clusters presently known. Those special conditions must be linked to the early formation epoch of the Galaxy and must not have occurred since. While a link to the formation of GCs in dwarf galaxies has been suggested, present-day dwarf galaxies are not representative of the gravitational potential wells within which the GCs formed. Instead, a formation deep within the proto-Galaxy or within dark-matter mini-haloes might be favoured. Not all GCs may have formed and evolved similarly. In particular, we may need to distinguish Galactic Halo from Galactic Bulge clusters.

  20. The Physical Origin of Galaxy Morphologies and Scaling Laws

    Science.gov (United States)

    Steinmetz, Matthias; Navarro, Julio F.

    2002-01-01

    We propose a numerical study designed to interpret the origin and evolution of galaxy properties revealed by space- and ground-based imaging and spectroscopical surveys. Our aim is to unravel the physical processes responsible for the development of different galaxy morphologies and for the establishment of scaling laws such as the Tully-Fisher relation for spirals and the Fundamental Plane of ellipticals. In particular, we plan to address the following major topics: (1) The morphology and observability of protogalaxies, and in particular the relationship between primordial galaxies and the z approximately 3 'Ly-break' systems identified in the Hubble Deep Field and in ground-based searches; (2) The origin of the disk and spheroidal components in galaxies, the timing and mode of their assembly, the corresponding evolution in galaxy morphologies and its sensitivity to cosmological parameters; (3) The origin and redshift evolution of the scaling laws that link the mass, luminosity size, stellar content, and metal abundances of galaxies of different morphological types. This investigation will use state-of-the-art N-body/gasdynamical codes to provide a spatially resolved description of the galaxy formation process in hierarchically clustering universes. Coupled with population synthesis techniques. our models can be used to provide synthetic 'observations' that can be compared directly with observations of galaxies both nearby and at cosmologically significant distances. This study will thus provide insight into the nature of protogalaxies and into the formation process of galaxies like our own Milky Way. It will also help us to assess the cosmological significance of these observations within the context of hierarchical theories of galaxy formation and will supply a theoretical context within which current and future observations can be interpreted.

  1. Serendipitous ALMA detections of faint submm galaxies in SERVS

    Science.gov (United States)

    Patil, Pallavi; Lacy, Mark; Nyland, Kristina

    2017-01-01

    We present a preliminary ALMA study of faint (piece of information is their morphologies at rest-frame optical wavelengths, which for high-redshift submm galaxies is only accessible through ALMA observations. The high sensitivity, spatial resolution, and positional accuracy of ALMA have enabled us to probe the nature of the sub-mJy population by resolving their spatial extents and improving constraints on their SEDS and photometric redshifts. We are building a catalog of sources by searching the ALMA archive for moderate to deep observations in the area covered by SERVS. This study will help us begin to understand the contribution of obscured star formation to the total star formation rate at high redshift and guide future wide-area surveys of submm galaxies with ALMA.

  2. Statistical issues in galaxy cluster cosmology

    DEFF Research Database (Denmark)

    Mantz, Adam; Allen, Steven W.; Rapetti Serra, David Angelo

    2013-01-01

    The number and growth of massive galaxy clusters is a sensitive probe of cosmological structure formation and dark energy. Surveys at various wavelengths can detect clusters to high redshift, but the fact that cluster mass is not directly observable complicates matters, requiring us to simultaneo......The number and growth of massive galaxy clusters is a sensitive probe of cosmological structure formation and dark energy. Surveys at various wavelengths can detect clusters to high redshift, but the fact that cluster mass is not directly observable complicates matters, requiring us...... to simultaneously constrain scaling relations of observable signals with mass. The problem can be cast in the form of a regression, in which the data set is truncated, the (cosmology-dependent) underlying population must be modeled, and strong, complex correlations between measurements often exist....

  3. The First Half Billion Years: Results from the Frontier Fields

    Science.gov (United States)

    Coe, Dan; Bradley, Larry; Zitrin, Adi

    2015-08-01

    The Frontier Fields program is transforming our understanding of galaxy evolution in the first 550 million years (z > 9). Where previous programs yielded perhaps a dozen z > 9 candidates, we estimate the Frontier Fields may yield up to ~70 (~6 per field). The first Frontier Fields images yielded strong z ~ 8 and 9 candidates, but fewer than expected at z > 9 (including one triply-imaged z ~ 10 candidate). By the time of this meeting, Hubble and Spitzer will have completed deep Frontier Fields imaging of the first four pairs of new "blank" fields and nearby fields strongly lensed by galaxy clusters. In this talk, I will present our latest high-redshift candidates, constraints on high-redshift luminosity functions, and implications for reionization. I will discuss whether the deficit of faint z > 9 galaxies persists (as also found in the UDF) and how incompleteness may be affecting our results.

  4. Extremes of the jet-accretion power relation of blazars, as explored by NuSTAR

    DEFF Research Database (Denmark)

    Sbarrato, T.; Ghisellini, G.; Tagliaferri, G.

    2016-01-01

    Hard X-ray observations are crucial to study the non-thermal jet emission from high-redshift, powerful blazars. We observed two bright z > 2 flat-spectrum radio quasars (FSRQs) in hard X-rays to explore the details of their relativistic jets and their possible variability. S5 0014+81 (at z = 3.......366) and B0222+185 (at z = 2.690) have been observed twice by the Nuclear Spectroscopic Telescope Array (NuSTAR) simultaneously with Swift/X-ray Telescope, showing different variability behaviours. We found that NuSTAR is instrumental to explore the variability of powerful high-redshift blazars, even when...

  5. Gravitational wave sirens as a triple probe of dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Linder, Eric V, E-mail: evlinder@lbl.gov [Berkeley Laboratory, University of California, Berkeley, CA 94720 (United States)

    2008-03-15

    Gravitational wave standard sirens have been considered as precision distance indicators of high redshift; however, at high redshift standard sirens or standard candles such as supernovae suffer from lensing noise. We investigate lensing noise as a signal instead and show how measurements of the maximum demagnification (minimum convergence) probe cosmology in a manner highly complementary to the distance itself. Revisiting the original form for minimum convergence we quantify the bias arising from the commonly used approximation. Furthermore, after presenting a new lensing probability function we discuss how the width of the lensed standard siren amplitude distribution also probes growth of structure. Thus standard sirens and candles can serve as triple probes of dark energy, measuring both the cosmic expansion history and growth history.

  6. Gravitational wave sirens as a triple probe of dark energy

    Science.gov (United States)

    Linder, Eric V.

    2008-03-01

    Gravitational wave standard sirens have been considered as precision distance indicators of high redshift; however, at high redshift standard sirens or standard candles such as supernovae suffer from lensing noise. We investigate lensing noise as a signal instead and show how measurements of the maximum demagnification (minimum convergence) probe cosmology in a manner highly complementary to the distance itself. Revisiting the original form for minimum convergence we quantify the bias arising from the commonly used approximation. Furthermore, after presenting a new lensing probability function we discuss how the width of the lensed standard siren amplitude distribution also probes growth of structure. Thus standard sirens and candles can serve as triple probes of dark energy, measuring both the cosmic expansion history and growth history.

  7. A Lyman Break Galaxy in the Epoch of Reionization from Hubble Space Telescope (HST) Grism Spectroscopy

    Science.gov (United States)

    Rhoads, James E.; Malhotra, Sangeeta; Stern, Daniel K.; Gardner, Jonathan P.; Dickinson, Mark; Pirzkal, Norbert; Spinrad, Hyron; Reddy, Naveen; Dey, Arjun; Hathi, Nimish; hide

    2013-01-01

    Slitless grism spectroscopy from space offers dramatic advantages for studying high redshift galaxies: high spatial resolution to match the compact sizes of the targets, a dark and uniform sky background, and simultaneous observation over fields ranging from five square arcminutes (HST) to over 1000 square arcminutes (Euclid). Here we present observations of a galaxy at z = 6.57 the end of the reioinization epoch identified using slitless HST grism spectra from the PEARS survey (Probing Evolution And Reionization Spectroscopically) and reconfirmed with Keck + DEIMOS. This high redshift identification is enabled by the depth of the PEARS survey. Substantially higher redshifts are precluded for PEARS data by the declining sensitivity of the ACS grism at greater than lambda 0.95 micrometers. Spectra of Lyman breaks at yet higher redshifts will be possible using comparably deep observations with IR-sensitive grisms.

  8. Implications for Primordial Non-Gaussianity ($f_{NL}$) from weak lensing masses of high-z galaxy clusters

    CERN Document Server

    Jimenez, Raul

    2009-01-01

    The recent weak lensing measurement of the dark matter mass of the high-redshift galaxy cluster XMMUJ2235.3-2557 of (8.5 +- 1.7) x 10^{14} Msun at z=1.4, indicates that, if the cluster is assumed to be the result of the collapse of dark matter in a primordial gaussian field in the standard LCDM model, then its abundance should be 3-10 if the non-Gaussianity parameter f^local_NL is in the range 150-200. This value is comparable to the limit for f_NL obtained by current constraints from the CMB. We conclude that mass determination of high-redshift, massive clusters can offer a complementary probe of primordial non-gaussianity.

  9. Diagnosis of Leishmania infantum infection by Polymerase Chain Reaction in wild mammals

    Directory of Open Access Journals (Sweden)

    Mayara C. Lombardi

    2014-12-01

    Full Text Available Visceral leishmaniasis is a chronic infectious disease caused by Leishmania infantum (synonym: Leishmania chagasi and transmitted by the sandfly Lutzomyia longipalpis in Brazil. It is an endemic zoonosis in several regions of the country, including Belo Horizonte (State of Minas Gerais. In urban areas, the domestic dog is susceptible and considered the most important animal reservoir. However, L. infantum has been previously diagnosed in other species, including captive primates and canids. This study aimed to evaluate the presence of the agent DNA in captive animals as well as some free ranging animals from the Zoo-Botanical Foundation of Belo Horizonte by Polymerase Chain Reaction. Eighty one blood samples from primates, carnivores, ruminants, edentates, marsupial, and a monogastric herbivore were analyzed. Three primates Alouatta guariba (brown howler monkey, and two canids Speothos venaticus (bush dog were positive, demonstrating the importance of leishmaniasis control in endemic areas for preservation of wildlife species in captivity.

  10. Human-wildlife interactions and zoonotic transmission of Echinococcus multilocularis.

    Science.gov (United States)

    Hegglin, Daniel; Bontadina, Fabio; Deplazes, Peter

    2015-05-01

    The life cycle of the zoonotic cestode Echinococcus multilocularis depends on canids (mainly red foxes) as definitive hosts and on their specific predation on rodent species (intermediate hosts). Host densities and predation rates are key drivers for infection with parasite eggs. We demonstrate that they strongly depend on multi-faceted human-wildlife interactions: vaccination against rabies, elimination of top predators, and changing attitude towards wildlife (feeding) contribute to high fox densities. The absence of large canids, low hunting pressure, and positive attitudes towards foxes modify their anti-predator response ('landscape of fear'), promoting their tameness, which in turn facilitates the colonization of residential areas and modifies parasite transmission. Such human factors should be considered in the assessment of any intervention and prevention strategy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. A Potential Tool for Swift Fox (Vulpes velox) Conservation: Individuality of Long-Range Barking Sequences

    DEFF Research Database (Denmark)

    Darden, Safi-Kirstine Klem; Dabelsteen, Torben; Pedersen, Simon Boel

    2003-01-01

    Vocal individuality has been found in a number canid species. This natural variation can have applications in several aspects of species conservation, from behavioral studies to estimating population density or abundance. The swift fox (Vulpes velox) is a North American canid listed as endangered...... context from 20 captive individuals (3 females and 17 males) housed in large, single-pair enclosures at a swift fox breeding facility. Using a discriminant function analysis with 7 temporal and spectral variables measured on barking sequences, we were able to correctly classify 99% of sequences...... to the correct individual. The most important discriminating variable was the mean spacing of barks in a barking sequence. Potential applications of such vocal individuality are discussed....

  12. DNA barcoding of three species (Canis aureus, Canis lupus and Vulpes vulpes) of Canidae.

    Science.gov (United States)

    Aksöyek, Eren; İbiş, Osman; Özcan, Servet; Moradi, Mohammad; Tez, Coşkun

    2017-09-01

    Sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene have been used for DNA barcoding and determining the genetic diversity of mammal species. In the current study, our intention was to test the validity of COI barcodes for detecting genetic divergence and to reveal whether or not there is a genetic variation at this marker within canids. Three species (Canis aureus, Canis lupus and Vulpes vulpes) from the family Canidae were selected for DNA barcoding using samples collected from Iran and Turkey. All three species had unique barcoding sequences and none of the sequences were shared among these species. The mean sequence divergences within and among the species were 0.61% and 12.32%, respectively, which fell into the mean divergence ranges found in some mammal groups. The genetic diversity of these three canid species was relatively higher than that found in previously reported studies.

  13. Isolation of viable Neospora caninum from brains of wild gray wolves (Canis lupus).

    Science.gov (United States)

    Dubey, J P; Jenkins, M C; Ferreira, L R; Choudhary, S; Verma, S K; Kwok, O C H; Fetterer, R; Butler, E; Carstensen, M

    2014-03-17

    Neospora caninum is a common cause of abortion in cattle worldwide. Canids, including the dog and the dingo (Canis familiaris), the coyote (Canis latrans), and the gray wolf (Canis lupus) are its definitive hosts that can excrete environmentally resistant oocysts in the environment, but also can act as intermediate hosts, harboring tissue stages of the parasite. In an attempt to isolate viable N. caninum from tissues of naturally infected wolves, brain and heart tissue from 109 wolves from Minnesota were bioassayed in mice. Viable N. caninum (NcWolfMn1, NcWolfMn2) was isolated from the brains of two wolves by bioassays in interferon gamma gene knockout mice. DNA obtained from culture-derived N. caninum tachyzoites of the two isolates were analyzed by N. caninum-specific Nc5 polymerase chain reaction and confirmed diagnosis. This is the first report of isolation of N. caninum from tissues of any wild canid host. Published by Elsevier B.V.

  14. Duration of immunity in red wolves (Canis rufus) following vaccination with a modified live parvovirus and canine distemper vaccine.

    Science.gov (United States)

    Anderson, Kadie; Case, Allison; Woodie, Kathleen; Waddell, William; Reed, Holly H

    2014-09-01

    There is growing information available regarding duration of immunity for core vaccines in both domestic and nondomestic species. Vaccination protocols in nondomestic canids have frequently followed guidelines developed for the domestic dog; however, these protocols can be inappropriate for nondomestic canids such as the African wild dog (Lycaon pictus), leaving some animals susceptible to infectious disease and others at risk for contracting vaccine-induced disease. In this study, red wolves (Canis rufus) were vaccinated against canine distemper virus (CDV) and canine parvovirus (CPV) and vaccination titers were followed annually for 3 yr. One hundred percent of wolves developed and maintained a positive titer to CDV for 3 yr and 96.9% of wolves developed and maintained a positive titer to CPV for 3 yr. Seroconversion for canine adenovirus was sporadic. The results of this study support decreasing the frequency of vaccine administration in the red wolf population to a triennial basis.

  15. An epigenetic aging clock for dogs and wolves.

    Science.gov (United States)

    Thompson, Michael J; vonHoldt, Bridgett; Horvath, Steve; Pellegrini, Matteo

    2017-03-28

    Several articles describe highly accurate age estimation methods based on human DNA-methylation data. It is not yet known whether similar epigenetic aging clocks can be developed based on blood methylation data from canids. Using Reduced Representation Bisulfite Sequencing, we assessed blood DNA-methylation data from 46 domesticated dogs ( Canis familiaris ) and 62 wild gray wolves ( C. lupus ). By regressing chronological dog age on the resulting CpGs, we defined highly accurate multivariate age estimators for dogs (based on 41 CpGs), wolves (67 CpGs), and both combined (115 CpGs). Age related DNA methylation changes in canids implicate similar gene ontology categories as those observed in humans suggesting an evolutionarily conserved mechanism underlying age-related DNA methylation in mammals.

  16. The wolf reference genome sequence (Canis lupus lupus) and its implications for Canis spp. population genomics

    DEFF Research Database (Denmark)

    Gopalakrishnan, Shyam; Samaniego Castruita, Jose Alfredo; Sinding, Mikkel Holger Strander

    2017-01-01

    Background An increasing number of studies are addressing the evolutionary genomics of dog domestication, principally through resequencing dog, wolf and related canid genomes. There is, however, only one de novo assembled canid genome currently available against which to map such data...... - that of a boxer dog (Canis lupus familiaris). We generated the first de novo wolf genome (Canis lupus lupus) as an additional choice of reference, and explored what implications may arise when previously published dog and wolf resequencing data are remapped to this reference. Results Reassuringly, we find......, then using the boxer reference genome is appropriate, but if the aim of the study is to look at the variation within wolves and their relationships to dogs, then there are clear benefits to using the de novo assembled wolf reference genome....

  17. Development of SED Camera for Quasars in Early Universe (SQUEAN)

    OpenAIRE

    Kim, Sanghyuk; Jeon, Yiseul; Lee, Hye-In; Park, Woojin; Ji, Tae-Geun; Hyun, Minhee; Choi, Changsu; Im, Myungshin; Pak, Soojong

    2016-01-01

    We describe the characteristics and performance of a camera system, Spectral energy distribution Camera for Quasars in Early Universe (SQUEAN). It was developed to measure SEDs of high redshift quasar candidates (z $\\gtrsim$ 5) and other targets, e.g., young stellar objects, supernovae, and gamma-ray bursts, and to trace the time variability of SEDs of objects such as active galactic nuclei (AGNs). SQUEAN consists of an on-axis focal plane camera module, an auto-guiding system, and mechanical...

  18. Photometric Redshifts Applied to WFPC2 and NICMOS HDF Data

    OpenAIRE

    Thompson, Rodger I.; Weymann, Ray J.; Storrie-Lombardi, Lisa J.

    1999-01-01

    A photometric redshift analysis of optical and infrared images of the Northern Hubble Deep Field indicate a constant star formation rate for redshifts between 1 and 6. The small size of the field and small number of high redshift objects limits this finding to just the area of the NICMOS image. The photometric redshift technique is a modified version of chi square fits to observed and calculated galaxy spectral energy distribution templates.

  19. Small Scale Perturbations in a General MDM Cosmology

    OpenAIRE

    Hu, Wayne; Eisenstein, Daniel J.

    1997-01-01

    For a universe with massive neutrinos, cold dark matter, and baryons, we solve the linear perturbation equations analytically in the small-scale limit and find agreement with numerical codes at the 1-2% level. The inclusion of baryons, a cosmological constant, or spatial curvature reduces the small-scale power and tightens limits on the neutrino density from observations of high redshift objects. Using the asymptotic solution, we investigate neutrino infall into potential wells and show that ...

  20. Dark Energy and Matter Evolution from Lensing Tomography

    OpenAIRE

    Hu, Wayne

    2002-01-01

    Reconstructed from lensing tomography, the evolution of the dark matter density field in the well-understood linear regime can provide model-independent constraints on the growth function of structure and the evolution of the dark energy density. We examine this potential in the context that high-redshift cosmology has in the future been fixed by CMB measurements. We construct sharp tests for the existence of multiple dark matter components or a dark energy component that is not a cosmologica...

  1. Structure Formation with Generalized Dark Matter

    OpenAIRE

    Hu, Wayne

    1998-01-01

    The next generation of cosmic microwave background (CMB) experiments, galaxy surveys, and high-redshift observations can potentially determine the nature of the dark matter observationally. With this in mind, we introduce a phenomenological model for a generalized dark matter (GDM) component and discuss its effect on large-scale structure and CMB anisotropies. Specifying the gravitational influence of the otherwise non-interacting GDM requires not merely a model for its equation of state but ...

  2. IMF of popIII stars.

    Science.gov (United States)

    Prieto, J. P.; Leopoldo, I.

    We performed a perturbation analisys of overdensity of a matter within high redshift halos in order to know the distribution in size of objects that can collapse in a first time. In order to see which objects can form stars we performed an analysis of the molecular cooling inside the first formed structures. This analysis give us a possible IMF for the first stars in the Univese.

  3. The Origin of Dust in High-z Galaxies

    Science.gov (United States)

    Dwek, Eli

    2010-01-01

    The discovery of massive amounts of dust in the high-redshift galaxy Jl148+5251, when the universe was merely'" 900 Myr old, presents a unique opportunity for studying the role of massive stars in the formation and destruction of dust grains, and the potential role of AGB as dust sources as well. In this talk I will review the different models for the presence of dust and the origin of the infrared emission in these galaxies.

  4. MaNGA: Mapping Nearby Galaxies at Apache Point Observatory

    Science.gov (United States)

    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.

  5. Are cold flows detectable with metal absorption lines?

    OpenAIRE

    Kimm, Taysun; Slyz, Adrianne; Devriendt, Julien; Pichon, Christophe

    2010-01-01

    [Abridged] Cold gas flowing within the "cosmic web" is believed to be an important source of fuel for star formation at high redshift. However, the presence of such filamentary gas has never been observationally confirmed. In this work, we investigate in detail whether such cold gas is detectable using low-ionisation metal absorption lines, such as CII \\lambda1334 as this technique has a proven observational record for detecting gaseous structures. Using a large statistical sample of galaxies...

  6. Associated HI Absorption in the = 3.4 Radio Galaxy B2 0902+ 343 ...

    Indian Academy of Sciences (India)

    We have made observations of the associated HI absorption of a high redshift radio galaxy 0902+34 at = 3.395 with the Giant Meterwave Radio Telescope in the 323+1 MHz band. We find a narrow absorption line with a flux density of 11.5 mJy at a redshift of 3.397 consistent with that observed by Uson et al. (1991) ...

  7. A HIGHER EFFICIENCY OF CONVERTING GAS TO STARS PUSHES GALAXIES AT z ∼ 1.6 WELL ABOVE THE STAR-FORMING MAIN SEQUENCE

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, J. D.; Rujopakarn, W. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Daddi, E.; Liu, D. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay (France); Rodighiero, G. [Dipartimento di Fisica e Astronomia, Universita di Padova, vicolo Osservatorio, 3, I-35122 Padova (Italy); Sargent, M. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Renzini, A. [Instituto Nazionale de Astrofisica, Osservatorio Astronomico di Padova, v.co dell’Osservatorio 5, I-35122 Padova (Italy); Feruglio, C. [IRAM—Institut de RadioAstronomie Millimétrique, 300 rue de la Piscine, F-38406 Saint Martin d’Hères (France); Kashino, D. [Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Nagoya 464-8602 (Japan); Sanders, D. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Kartaltepe, J. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Nagao, T. [Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan); Arimoto, N. [Subaru Telescope, 650 North A’ohoku Place, Hilo, HI-96720 (United States); Berta, S.; Lutz, D. [Max-Planck-Institut für extraterrestrische Physik, D-84571 Garching (Germany); Béthermin, M. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Koekemoer, A., E-mail: john.silverman@ipmu.jp [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218 (United States); and others

    2015-10-20

    Local starbursts have a higher efficiency of converting gas into stars, as compared to typical star-forming galaxies at a given stellar mass, possibly indicative of different modes of star formation. With the peak epoch of galaxy formation occurring at z > 1, it remains to be established whether such an efficient mode of star formation is occurring at high redshift. To address this issue, we measure the molecular gas content of seven high-redshift (z ∼ 1.6) starburst galaxies with the Atacama Large Millimeter/submillimeter Array and IRAM/Plateau de Bure Interferometer. Our targets are selected from the sample of Herschel far-infrared-detected galaxies having star formation rates (∼300–800 M{sub ⊙} yr{sup −1}) elevated (≳4×) above the star-forming main sequence (MS) and included in the FMOS-COSMOS near-infrared spectroscopic survey of star-forming galaxies at z ∼ 1.6 with Subaru. We detect CO emission in all cases at high levels of significance, indicative of high gas fractions (∼30%–50%). Even more compelling, we firmly establish with a clean and systematic selection that starbursts, identified as MS outliers, at high redshift generally have a lower ratio of CO to total infrared luminosity as compared to typical MS star-forming galaxies, although with a smaller offset than expected based on past studies of local starbursts. We put forward a hypothesis that there exists a continuous increase in star formation efficiency with elevation from the MS with galaxy mergers as a possible physical driver. Along with a heightened star formation efficiency, our high-redshift sample is similar in other respects to local starbursts, such as being metal rich and having a higher ionization state of the interstellar medium.

  8. La frontera a alto corrimiento al rojo: historia de la formacio'n de las galaxias

    OpenAIRE

    Miralda-Escude, Jordi

    1999-01-01

    This review presents a brief discussion of the theory of Cold Dark Matter of structure formation in the universe, describing the main processes determining the power spectrum, the non-linear gravitational collapse, the formation of galaxies and the evolution of the intergalactic medium. Recent advances in the observations of high redshift galaxies, and their interpretation in the context of this theory, are then summarized. Este art\\'\\i culo de revisi\\'on presenta una breve exposici\\'on de la...

  9. Cutoff in the Lyman-$\\alpha$ forest power spectrum: warm IGM or warm dark matter?

    OpenAIRE

    Garzilli, Antonella; Boyarsky, Alexey; Ruchayskiy, Oleg

    2015-01-01

    We re-analyse high redshift and high resolution Lyman-$\\alpha$ forest spectra considered in (Viel et al 2013), seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. We find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories...

  10. Cutoff in the Lyman- α forest power spectrum: Warm IGM or warm dark matter?

    OpenAIRE

    Garzilli, Antonella; Boyarsky, Alexey; Ruchayskiy, Oleg

    2017-01-01

    We re-analyse high redshift and high resolution Lyman- α forest spectra considered in [1] , seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. We find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories and underlying rei...

  11. Cutoff in the Lyman-α forest power spectrum: Warm IGM or warm dark matter?

    OpenAIRE

    Antonella Garzilli; Alexey Boyarsky; Oleg Ruchayskiy

    2017-01-01

    We re-analyse high redshift and high resolution Lyman-α forest spectra considered in [1], seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. We find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories and underlying reion...

  12. Dust in External Galaxies

    OpenAIRE

    Calzetti, Daniela

    2009-01-01

    Existing (Spitzer Space Telescope) and upcoming (Herschel Space Telescope) facilities are deepening our understanding of the role of dust in tracing the energy budget and chemical evolution of galaxies. The tools we are developing while exploring the local Universe will in turn become pivotal in the interpretation of the high redshift Universe when near--future facilities (the Atacama Large Millimeter Array [ALMA], the Sub--Millimeter Array [SMA], the Large Millimeter Telescope [LMT], the Jam...

  13. UV Properties of High-Z Supernovae Found In Archival CFHTLS Data

    Science.gov (United States)

    Pritchard, Tyler A.; Cooke, Jeff

    2016-01-01

    Using a novel technique to detect z≥1.7 archival supernovae in the CFHT Legacy Survey (CFHTLS) we discuss rest-frame UV comparisons between a local sample comprised of Swift (photometric) and HST (spectroscopic) data and a high redshift CFHTLS (photometric) + Keck/LRIS (spectroscopic); as well as observations on the horizon for z≥2.5 Superluminous supernovae (SLSN) found through the Search for Superluminous Supernovae using DECam (SUDSS) and it's u-band companion program necessary for this technique.

  14. Constraining Cosmic Evolution of Type Ia Supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Foley, Ryan J.; Filippenko, Alexei V.; Aguilera, C.; Becker, A.C.; Blondin, S.; Challis, P.; Clocchiatti, A.; Covarrubias, R.; Davis, T.M.; Garnavich, P.M.; Jha, S.; Kirshner, R.P.; Krisciunas, K.; Leibundgut, B.; Li, W.; Matheson, T.; Miceli, A.; Miknaitis, G.; Pignata, G.; Rest, A.; Riess, A.G.; /UC, Berkeley, Astron. Dept. /Cerro-Tololo InterAmerican Obs. /Washington U., Seattle, Astron. Dept. /Harvard-Smithsonian Ctr. Astrophys. /Chile U., Catolica /Bohr Inst. /Notre Dame U. /KIPAC, Menlo Park /Texas A-M /European Southern Observ. /NOAO, Tucson /Fermilab /Chile U., Santiago /Harvard U., Phys. Dept. /Baltimore, Space Telescope Sci. /Johns Hopkins U. /Res. Sch. Astron. Astrophys., Weston Creek /Stockholm U. /Hawaii U. /Illinois U., Urbana, Astron. Dept.

    2008-02-13

    We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 ultraviolet spectra obtained by HST/IUE. The low-redshift spectra act as a control sample when comparing to the ESSENCE spectra. In all instances, the ESSENCE and Lick composite spectra appear very similar. The addition of galaxy light to the Lick composite spectra allows a nearly perfect match of the overall spectral-energy distribution with the ESSENCE composite spectra, indicating that the high-redshift SNe are more contaminated with host-galaxy light than their low-redshift counterparts. This is caused by observing objects at all redshifts with similar slit widths, which corresponds to different projected distances. After correcting for the galaxy-light contamination, subtle differences in the spectra remain. We have estimated the systematic errors when using current spectral templates for K-corrections to be {approx}0.02 mag. The variance in the composite spectra give an estimate of the intrinsic variance in low-redshift maximum-light SN spectra of {approx}3% in the optical and growing toward the ultraviolet. The difference between the maximum-light low and high-redshift spectra constrain SN evolution between our samples to be < 10% in the rest-frame optical.

  15. The Spitzer/Swift Gamma-Ray Burst Host Galaxy Legacy Survey

    Science.gov (United States)

    Perley, Daniel; Berger, Edo; Butler, Nathaniel; Cenko, S. Bradley; Chary, Ranga-Ram; Cucchiara, Antonino; Ellis, Richard; Fong, Wen-fai; Fruchter, Andrew; Fynbo, Johan; Gehrels, Neil; Graham, John; Greiner, Jochen; Hjorth, Jens; Hunt, Leslie; Jakobsson, Pall; Kruehler, Thomas; Laskar, Tanmoy; Le Floc'h, Emerich; Levan, Andrew; Levesque, Emily; Littlejohns, Owen; Malesani, Daniele; Michalowski, Michal; Milvang-Jensen, Bo; Prochaska, J. Xavier; Salvaterra, Ruben; Schulze, Steve; Schady, Patricia; Tanvir, Nial; de Ugarte Postigo, Antonio; Vergani, Susanna; Watson, Darach

    2016-08-01

    Long-duration gamma-ray bursts act as beacons to the sites of star-formation in the distant universe. GRBs reveal galaxies too faint and star-forming regions too dusty to characterize in detail using any other method, and provide a powerful independent constraint on the evolution of the cosmic star-formation rate density at high-redshift. However, a full understanding of the GRB phenomenon and its relation to cosmic star-formation requires connecting the observations obtained from GRBs to the properties of the galaxies hosting them. The large majority of GRBs originate at moderate to high redshift (z>1) and Spitzer has proven crucial for understanding the host population, given its unique ability to observe the rest-frame NIR and its unrivaled sensitivity and efficiency. We propose to complete a comprehensive public legacy survey of the Swift GRB host population to build on our earlier successes and push beyond the statistical limits of previous, smaller efforts. Our survey will enable a diverse range of GRB and galaxy science including: (1) to quantitatively and robustly map the connection between GRBs and cosmic star-formation to constrain the GRB progenitor and calibrate GRB rate-based measurements of the high-z cosmic star-formation rate; (2) to constrain the luminosity function of star-forming galaxies at the faint end and at high redshift; (3) to understand how the ISM properties seen in absorption in high-redshift galaxies unveiled by GRBs - metallicity, dust column, dust properties - connect to global properties of the host galaxies such as mass and age. Building on a decade of experience at both observatories, our observations will create an enduring joint Swift-Spitzer legacy sample - providing the definitive resource with which to examine all aspects of the GRB/galaxy connection for years to come and setting the stage for intensive JWST follow-up of the most interesting sources from our sample.

  16. On Inferring Extinction Laws in Z -approximately 6 Quasars as Signatures of Supernova Dust

    Science.gov (United States)

    Hjorth, Jens; Vreeswijk, Paul M.; Gall, Christa; Watson, Darach

    2013-01-01

    Unusual extinction curves of high-redshift QSOs have been taken as evidence that dust is primarily produced by supernovae at high redshift. In particular, the 3000 °A Todini-Ferrara-Maiolino kink in the extinction curve of the z = 6.20 SDSS J1048+4637 has been attributed to supernova dust. Here we discuss the challenges in inferring robust extinction curves of high-redshift QSOs and critically assess previous claims of detection of supernova dust. In particular, we address the sensitivity to the choice of intrinsic QSO spectrum, the need for a long wavelength baseline, and the drawbacks in fitting theoretical extinction curves. In a sample of 21 QSOs at z 6 we detect significant ultraviolet extinction using existing broad-band optical, near-infrared, and Spitzer photometry. The median extinction curve is consistent with a Small Magellanic Cloud curve with A1450 0.7 mag and does not exhibit any conspicuous (restframe) 2175 °A or 3000 °A features. For two QSOs, SDSS J1044-0125 at z = 5.78 and SDSS J1030+0524 at z = 6.31, we further present X-shooter spectra covering the wavelength range 0.9-2.5 µm. The resulting non-parametric extinction curves do not exhibit the 3000 °A kink. Finally, in a re-analysis of literature spectra of SDSS J1048+4637, we do not find evidence for a conspicuous kink. We conclude that the existing evidence for a 3000 °A feature is weak and that the overall dust properties at high and low redshift show no significant differences. This, however, does not preclude supernovae from dominating the dust budget at high redshift.

  17. Searching for Star Formation Beyond Reionization

    OpenAIRE

    Barton, Elizabeth J.; Dav'e, Romeel; Smith, John-David T.; Papovich, Casey; Hernquist, Lars; Springel, Volker

    2003-01-01

    The goal of searching back in cosmic time to find star formation during the epoch of reionization will soon be within reach. We assess the detectability of high-redshift galaxies by combining cosmological hydrodynamic simulations of galaxy formation, stellar evolution models appropriate for the first generations of stars, and estimates of the efficiency for Lyman alpha to escape from forming galaxies into the intergalactic medium. Our simulated observations show that Lyman alpha emission at z...

  18. The PRIME Project: A Proposal for Fermilab to Join a NASA SMEX

    Energy Technology Data Exchange (ETDEWEB)

    Kent, Stephen [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Annis, Jim [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Kron, Rich [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lee, Brian [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lin, Huan [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Peoples, John [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Stoughton, Chris [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Tucker, Douglas [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Yanny, Brian [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); VandenBerk, Dan [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Petravick, Don [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Holmgren, Don [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States). et al.

    2001-10-08

    The Primordial Explorer (PRIME) is a proposed satellite designed to conduct an infrared imaging survey of 1/4 of the sky, with a principal science goal of probing the universe at redshifts greater than 1. We expect to use the data from PRIME to extend our Sloan Digital Sky Survey-based studies of the distribution of mass in the Universe to the high redshift frontier.

  19. Enhanced X-ray emission from Lyman Break Analogues and a Possible $L_{\\rm X}$--SFR--Metallicity Plane

    OpenAIRE

    Brorby, Matthew; Kaaret, Philip; Prestwich, Andrea; Mirabel, I. Felix

    2016-01-01

    The source of energetic photons that heated and reionized the early Universe remains uncertain. Early galaxies had low metallicity and recent population synthesis calculations suggest that the number and luminosity of high-mass X-ray binaries are enhanced in star-forming galaxies with low metallicity, offering a potentially important and previously overlooked source of heating and reionization. Lyman break analogue (LBA) galaxies are local galaxies that strongly resemble the high-redshift, st...

  20. The high-energy neutrino background - Limitations on models of deuterium production

    Science.gov (United States)

    Eichler, D.

    1979-01-01

    It is pointed out that Epstein's (1977) model for deuterium production via high-energy spallation reactions produces high-energy neutrinos in sufficient quantity to stand out above those that are produced by cosmic-ray interactions in earth's atmosphere. That the Reines experiment detected neutrinos of atmospheric origin without detecting any cosmic component restricts deuterium production by spallation reactions to very high redshifts (z at least about 300). Improved neutrino experiments may be able to push these limits back to recombination.

  1. Type Ia Supernova Distance Modulus Bias and Dispersion From K-correction Errors: A Direct Measurement Using Lightcurve Fits to Observed Spectral Time Series

    OpenAIRE

    C. Saunders; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A; Cellier-Holzem, F.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Feindt, U.

    2014-01-01

    We estimate systematic errors due to K-corrections in standard photometric analyses of high redshift Type Ia supernovae. Errors due to K-correction occur when the spectral template model underlying the lightcurve fitter poorly represents the actual supernova spectral energy distribution, meaning that the distance modulus cannot be recovered accurately. In order to quantify this effect, synthetic photometry is performed on artificially redshifted spectrophotometric data from 119 low-redshift s...

  2. The complete mitochondrial genome sequence of the Tibetan wolf (Canis lupus laniger).

    Science.gov (United States)

    Zhao, Chao; Zhang, Honghai; Zhang, Jin; Chen, Lei; Sha, Weilai; Yang, Xiufeng; Liu, Guangshuai

    2016-01-01

    In this study, the complete mitochondrial genome of the Tibetan wolf (Canis lupus laniger) was sequenced using blood samples obtained from a wild female Tibetan wolf captured from Lhasa in Tibet, China. Qinghai-Tibet Plateau, with an average elevation above 3500 m, is the highest plateau in the world. Sequence analysis showed that its structure is in accordance with other Canidae species, but GTG is used as the start codon in ND4L gene which is different from many canide animals.

  3. The predatory behaviour of the thylacine: Tasmanian tiger or marsupial wolf?

    OpenAIRE

    Figueirido, Borja; Janis, Christine M.

    2011-01-01

    The extinct thylacine (Thylacinus cynocephalus) and the extant grey wolf (Canis lupus) are textbook examples of convergence between marsupials and placentals. Craniodental studies confirm the thylacine's carnivorous diet, but little attention has been paid to its postcranial skeleton, which would confirm or refute rare eyewitness reports of a more ambushing predatory mode than the pack-hunting pursuit mode of wolves and other large canids. Here we show that thylacines had the elbow morphology...

  4. Morphological and molecular identification of Dirofilaria immitis from Jackal (Canis aureus) in North Khorasan, northeast Iran

    OpenAIRE

    Zahra Heidari; Eshrat B Kia; Kourosh Arzamani; Meysam Sharifdini; Iraj Mobedi; Zabihollah Zarei; Bahareh Kamranrashani

    2015-01-01

    Background & objectives: The heartworm Dirofilaria immitis is an important mosquito-borne zoonotic nematode of domestic and wild mammals throughout the world, causing cardiopulmonary dirofilariasis. This parasite has been reported from carnivores in some provinces of Iran. However, in the present study, the occurrence of this filarial nematode is reported for the first time in wild canids of the North Khorasan Province, located in northeast Iran, based on morphological and molecular character...

  5. Exposure to infectious agents in dogs in remote coastal British Columbia: Possible sentinels of diseases in wildlife and humans

    OpenAIRE

    Bryan, Heather M.; Darimont, Chris T.; Paquet, Paul C.; Ellis, John A.; Goji, Noriko; Gouix, Maëlle; Smits, Judit E.

    2011-01-01

    Ranked among the top threats to conservation worldwide, infectious disease is of particular concern for wild canids because domestic dogs (Canis familiaris) may serve as sources and reservoirs of infection. On British Columbia’s largely undeveloped but rapidly changing central and north coasts, little is known about diseases in wolves (Canis lupus) or other wildlife. However, several threats exist for transfer of diseases among unvaccinated dogs and wolves. To gain baseline data on infectious...

  6. Canine Visceral Leishmaniasis, United States and Canada, 2000–2003

    OpenAIRE

    Duprey, Zandra H.; Steurer, Francis J.; Rooney, Jane A.; Kirchhoff, Louis V.; Jackson, Joan E.; Rowton, Edgar D.; Peter M. Schantz

    2006-01-01

    Visceral leishmaniasis, caused by protozoa of the genus Leishmania donovani complex, is a vectorborne zoonotic infection that infects humans, dogs, and other mammals. In 2000, this infection was implicated as causing high rates of illness and death among foxhounds in a kennel in New York. A serosurvey of >12,000 foxhounds and other canids and 185 persons in 35 states and 4 Canadian provinces was performed to determine geographic extent, prevalence, host range, and modes of transmission within...

  7. Canine parvovirus effect on wolf population change and pup survival

    Science.gov (United States)

    Mech, L.D.; Goyal, S.M.

    1993-01-01

    Canine parvovirus infected wild canids more than a decade ago, but no population effect has been documented. In wild Minnesota wolves (Canis lupus) over a 12-yr period, the annual percent population increase and proportion of pups each were inversely related to the percentage of wolves serologically positive to the disease. Although these effects did not seem to retard this large extant population, similar relationships in more isolated wolf populations might hinder recovery of this endangered and threatened species.

  8. Genomic characterization of the italian wolf (Canis lupus): the genes involved in black coat colour determination and application of microarray technique for snps detection.

    OpenAIRE

    Greco, Claudia

    2009-01-01

    This study provides a comprehensive genetic overview on the endangered Italian wolf population. In particular, it focuses on two research lines. On one hand, we focalised on melanism in wolf in order to isolate a mutation related with black coat colour in canids. With several reported black individuals (an exception at European level), the Italian wolf population constituted a challenging research field posing many unanswered questions. As found in North American wolf, we re...

  9. Comparative Transcriptome Analysis of Raccoon Dog Skin to Determine Melanin Content in Hair and Melanin Distribution in Skin

    OpenAIRE

    Zhanyu Du; Kai Huang; Jiaping Zhao; Xingchao Song; Xiumei Xing; Qiong Wu; Linbo Zhang; Chao Xu

    2017-01-01

    The raccoon dog (Nyctereutes procyonoides) is an important canid fur-bearing animal species worldwide. Chinese raccoon dogs that present a white mutation, especially those with a white coat. Exploring melanin biosynthesis in the hair and skin of raccoon dogs is important for understanding the survival and evolutionary mechanisms of them. In this study, we measured the content of melanin in the hair of two types of raccoon dog and generated stained slices of skin tissue. The results indicated ...

  10. A protected area influences genotype-specific survival and the structure of a Canis hybrid zone.

    Science.gov (United States)

    Benson, John F; Patterson, Brent R; Mahoney, Peter J

    2014-02-01

    It is widely recognized that protected areas can strongly influence ecological systems and that hybridization is an important conservation issue. However, previous studies have not explicitly considered the influence of protected areas on hybridization dynamics. Eastern wolves are a species of special concern and their distribution is largely restricted to a protected population in Algonquin Provincial Park (APP), Ontario, Canada, where they are the numerically dominant canid. We studied intrinsic and extrinsic factors influencing survival and cause-specific mortality of hybrid and parental canids in the three-species hybrid zone between eastern wolves, eastern coyotes, and gray wolves in and adjacent to APP. Mortality risk for eastern wolves in areas adjacent to APP was significantly higher than for other sympatric Canis types outside of APP, and for eastern wolves and other canids within APP. Outside of APP, the annual mortality rate of all canids by harvest (24%) was higher than for other causes of death (4-7%). Furthermore, eastern wolves (hazard ratio = 3.5) and nonresidents (transients and dispersing animals, hazard ratio = 2.7) were more likely to die from harvest relative to other Canis types and residents, respectively. Thus, eastern wolves dispersing from APP were especially vulnerable to harvest mortality. For residents, eastern wolf survival was more negatively influenced by increased road density than for other Canis types, further highlighting the sensitivity of eastern wolves to human disturbance. A cycle of dispersal from APP followed by high rates of mortality and hybridization appears to maintain eastern wolves at low density adjacent to APP, limiting the potential for expansion beyond the protected area. However, high survival and numerical dominance of eastern wolves within APP suggest that protected areas can allow rare hybridizing species to persist even if their demographic performance is compromised and barriers to hybridization are largely

  11. Bilateral cataracts in a coyote (Canis latrans) pup from Saskatchewan, Canada.

    Science.gov (United States)

    Granson, Hilary; Grahn, Bruce; Parker, Dennilyn; Himsworth, Chelsea

    2010-06-01

    A free-ranging coyote (Canis latrans) pup was found in rural Saskatchewan and was subsequently presented to a veterinary teaching hospital by a wildlife rehabilitator. On physical examination, the pup was found to be blind as a result of bilateral, mature cataracts, which were confirmed on postmortem examination. No other significant intraocular or extraocular disease was detected, resulting in a presumptive diagnosis of congenital cataract. To the authors' knowledge, this is the first report of congenital cataract in any wild canid species.

  12. A 33,000-year-old incipient dog from the Altai Mountains of Siberia: evidence of the earliest domestication disrupted by the Last Glacial Maximum.

    Directory of Open Access Journals (Sweden)

    Nikolai D Ovodov

    Full Text Available BACKGROUND: Virtually all well-documented remains of early domestic dog (Canis familiaris come from the late Glacial and early Holocene periods (ca. 14,000-9000 calendar years ago, cal BP, with few putative dogs found prior to the Last Glacial Maximum (LGM, ca. 26,500-19,000 cal BP. The dearth of pre-LGM dog-like canids and incomplete state of their preservation has until now prevented an understanding of the morphological features of transitional forms between wild wolves and domesticated dogs in temporal perspective. METHODOLOGY/PRINCIPAL FINDING: We describe the well-preserved remains of a dog-like canid from the Razboinichya Cave (Altai Mountains of southern Siberia. Because of the extraordinary preservation of the material, including skull, mandibles (both sides and teeth, it was possible to conduct a complete morphological description and comparison with representative examples of pre-LGM wild wolves, modern wolves, prehistoric domesticated dogs, and early dog-like canids, using morphological criteria to distinguish between wolves and dogs. It was found that the Razboinichya Cave individual is most similar to fully domesticated dogs from Greenland (about 1000 years old, and unlike ancient and modern wolves, and putative dogs from Eliseevichi I site in central Russia. Direct AMS radiocarbon dating of the skull and mandible of the Razboinichya canid conducted in three independent laboratories resulted in highly compatible ages, with average value of ca. 33,000 cal BP. CONCLUSIONS/SIGNIFICANCE: The Razboinichya Cave specimen appears to be an incipient dog that did not give rise to late Glacial-early Holocene lineages and probably represents wolf domestication disrupted by the climatic and cultural changes associated with the LGM. The two earliest incipient dogs from Western Europe (Goyet, Belguim and Siberia (Razboinichya, separated by thousands of kilometers, show that dog domestication was multiregional, and thus had no single place of

  13. The Eurasian otter (Lutra lutra) as a potential host for rickettsial pathogens in southern Italy

    OpenAIRE

    Santoro, Mario; D?Alessio, Nicola; Cerrone, Anna; Lucibelli, Maria Gabriella; Borriello, Giorgia; Aloise,Gaetano; Auriemma, Clementina; Riccone, Nunzia; Galiero, Giorgio

    2017-01-01

    Canine monocytic ehrlichiosis and rickettsiosis are zoonotic tick-borne diseases of canids caused by the intracellular obligate bacteria Ehrlichia canis and Rickettsia species respectively. In this study, we investigated using standard and real-time PCR and sequencing, the occurrence and molecular characterization of E. canis and Rickettsia species in the Eurasian otter (Lutra lutra) from the southern Italian population. Samples were screened by using molecular assays also for Neospora caninu...

  14. Contribución al conocimiento de la fauna fósil de Torralba - Ambrona, Soria (España). Parte I

    OpenAIRE

    Fuentes Vidarte, C.

    1993-01-01

    [ES] Se estudia parte de la fauna fósil del yacimiento de Torralba-Ambrona de Soria, campañas 1961-63: aves, lagomorfos, primates y cánidos. Se describe una nueva subespecie de cánido, Canis lupus ambronensis. [EN] Estudied part of the fossil Fauna of the Torralba-Ambrona deposit, excavations 1961-63: birds, rabbits, primates and canines. Described a new canid, Canis lupus ambronensis.

  15. Prüfung von Baypamune® im Infektionsmodell der kaninen oralen Papillomatose am Hund

    OpenAIRE

    März, Maren

    2007-01-01

    Canine Oral Papillomavirus (COPV) induces warts on the oral mucosa in domestic dogs and other canids. The canine oral papillomatosis (COP) is a well established animal model of mucosal papillomatosis. While the regression of a current infection is mediated by cellular immunity, humoral immunity does prevent reinfection. Question of the present study was, if unspecific stimulation of the immune system with the inducer of paramunity Baypamune® during the period of growth would have an influence...

  16. Modelling disjunct carnivore distributions: the case of the wolf (Canis lupus) in the Iberian Peninsula

    OpenAIRE

    Barbosa, A.M.; Puerto, M.A.; Figueiredo, D.; Real, R.

    2012-01-01

    Book Description: In this book, the authors present current research in the conservation, species and management of carnivores. Topics discussed include the adaptation, impact and management of the raccoon dog in Europe; human perceptions of cougars in Canada and El Salvador; the impact on wildlife conservation of emerging protozoal tick-borne diseases of canids; mitigating conflict between humans and large carnivores in carnivore conservation; the management and conservation of wolves in the...

  17. Parasite species of the endangered Iberian wolf (Canis lupus signatus) and a sympatric widespread carnivore

    OpenAIRE

    Figueiredo, Ana; Oliveira, Lucia; Madeira de Carvalho, Lu?s; Fonseca, Carlos; Torres, Rita Tinoco

    2016-01-01

    Parasites have a profound impact on wildlife population dynamics. However, until some years ago, studies on the occurrence and prevalence of wildlife parasites were neglected comparatively with the studies on humans and domestic animals. In this study, we determined the parasite prevalence of two sympatric wild canids: the endangered Iberian wolf (Canis lupus signatus) and the widespread red fox (Vulpes vulpes), in central Portugal. From November 2014 to July 2015, fresh fecal samples from bo...

  18. Cranial functional morphology of fossil dogs and adaptation for durophagy in Borophagus and Epicyon (Carnivora, Mammalia).

    Science.gov (United States)

    Tseng, Zhijie Jack; Wang, Xiaoming

    2010-11-01

    Morphological specialization is a complex interplay of adaptation and constraint, as similarly specialized features often evolve convergently in unrelated species, indicating that there are universally adaptive aspects to these morphologies. The evolutionary history of carnivores offers outstanding examples of convergent specialization. Among larger predators, borophagine canids were highly abundant during the tertiary of North America and are regarded as the ecological vicars of Afro-Eurasian hyenas. Borophaginae is an extinct group of 60+ species, the largest forms evolving robust skulls with prominently domed foreheads, short snouts, and hypertrophied fourth premolars. These specializations have been speculated to enhance bone cracking. To test the extent that the skulls of derived borophagines were adapted for producing large bite forces and withstanding the mechanical stresses associated with bone cracking relative to their nonrobust sister clades, we manipulated muscle forces in models of six canid skulls and analyzed their mechanical response using 3D finite element analysis. Performance measures of bite force production efficiency and deformation minimization showed that skulls of derived borophagines Borophagus secundus and Epicyon haydeni are particularly strong in the frontal region; maximum stresses are lower and more evenly distributed over the skull than in other canids. Frontal strength is potentially coupled with a temporalis-driven bite to minimize cranial stress during biting in the two derived genera, as tensile stress incurred by contracting temporalis muscles is dissipated rostro-ventrally across the forehead and face. Comparison of estimated masticatory muscle cross section areas suggests that the temporalis-masseter ratio is not strongly associated with morphological adaptations for bone cracking in Borophagus and Epicyon; larger body size may explain relatively larger temporalis muscles in the latter. When compared with previous studies, the

  19. Species distribution modeling for the invasive raccoon dog (Nyctereutes procyonoides) in Austria and first range predictions for alpine environments

    OpenAIRE

    Duscher Tanja; Nopp-Mayr Ursula

    2017-01-01

    Species distribution models are important tools for wildlife management planning, particularly in the case of invasive species. We employed a recent framework for niche-based invasive species distribution modeling to predict the probability of presence for the invasive raccoon dog (Nyctereutes procyonoides) in Austria. The raccoon dog is an adaptive, mobile and highly reproductive Asiatic canid that has successfully invaded many parts of Europe. It is known...

  20. Psík mývalovitý (Nyctereutes procyonides) ve střední Evropě: historie šíření a stav znalostí

    OpenAIRE

    Pyšková, Klára

    2014-01-01

    The thesis is about the raccoon dog (Nyctereutes procyonoides), a canid invasive in a large part of Europe. It describes its distribution in native and invaded range, the history of colonisation, ecology and social behaviour, as well as its impact in the invaded range. Available knowledge is summarized, with main focus on central Europe. The native distribution range of the species is in eastern Asia. The animals were first brought to the European part of the former Soviet Union in the first ...