WorldWideScience

Sample records for spitzer galactic legacy

  1. Spitzer Digs Up Galactic Fossil

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Figure 1 [figure removed for brevity, see original site] Figure 2 This false-color image taken by NASA's Spitzer Space Telescope shows a globular cluster previously hidden in the dusty plane of our Milky Way galaxy. Globular clusters are compact bundles of old stars that date back to the birth of our galaxy, 13 or so billion years ago. Astronomers use these galactic 'fossils' as tools for studying the age and formation of the Milky Way. Most clusters orbit around the center of the galaxy well above its dust-enshrouded disc, or plane, while making brief, repeated passes through the plane that each last about a million years. Spitzer, with infrared eyes that can see into the dusty galactic plane, first spotted the newfound cluster during its current pass. A visible-light image (inset of Figure 1) shows only a dark patch of sky. The red streak behind the core of the cluster is a dust cloud, which may indicate the cluster's interaction with the Milky Way. Alternatively, this cloud may lie coincidentally along Spitzer's line of sight. Follow-up observations with the University of Wyoming Infrared Observatory helped set the distance of the new cluster at about 9,000 light-years from Earth - closer than most clusters - and set the mass at the equivalent of 300,000 Suns. The cluster's apparent size, as viewed from Earth, is comparable to a grain of rice held at arm's length. It is located in the constellation Aquila. Astronomers believe that this cluster may be one of the last in our galaxy to be uncovered. This image composite was taken on April 21, 2004, by Spitzer's infrared array camera. It is composed of images obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). Galactic Fossil Found Behind Curtain of Dust In Figure 2, the image mosaic shows the same patch of sky in various wavelengths of light. While the visible-light image (left) shows a dark sky speckled

  2. PLANETARY NEBULAE DETECTED IN THE SPITZER SPACE TELESCOPE GLIMPSE II LEGACY SURVEY

    International Nuclear Information System (INIS)

    Zhang Yong; Sun Kwok

    2009-01-01

    We report the result of a search for the infrared counterparts of 37 planetary nebulae (PNs) and PN candidates in the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire II (GLIMPSE II) survey. The photometry and images of these PNs at 3.6, 4.5, 5.8, 8.0, and 24 μm, taken through the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer for Spitzer (MIPS), are presented. Most of these nebulae are very red and compact in the IRAC bands, and are found to be bright and extended in the 24 μm band. The infrared morphology of these objects are compared with Hα images of the Macquarie-AAO-Strasbourg (MASH) and MASH II PNs. The implications for morphological difference in different wavelengths are discussed. The IRAC data allow us to differentiate between PNs and H II regions and be able to reject non-PNs from the optical catalog (e.g., PNG 352.1 - 00.0). Spectral energy distributions are constructed by combing the IRAC and MIPS data with existing near-, mid-, and far-IR photometry measurements. The anomalous colors of some objects allow us to infer the presence of aromatic emission bands. These multi-wavelength data provide useful insights into the nature of different nebular components contributing to the infrared emission of PNs.

  3. SPITZER PARALLAX OF OGLE-2015-BLG-0966: A COLD NEPTUNE IN THE GALACTIC DISK

    Energy Technology Data Exchange (ETDEWEB)

    Street, R. A.; Bachelet, E. [LCOGT, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Novati, S. Calchi [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Hundertmark, M. P. G.; Jørgensen, U. G. [Niels Bohr Institute and Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350—Copenhagen K (Denmark); Zhu, W.; Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Yee, J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Tsapras, Y. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), D-69120 Heidelberg (Germany); Bennett, D. P. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Dominik, M. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Andersen, M. I. [Niels Bohr Institute and Dark Cosmology Centre, University of Copenhagen, Juliane Mariesvej 30, DK-2100—Copenhagen Ø (Denmark); Bozza, V. [Dipartimento di Fisica “E.R. Caianiello,” Università di Salerno, Via Giovanni Paolo II 132, I-84084, Fisciano (Italy); Bramich, D. M. [Qatar Environment and Energy Research Institute, Qatar Foundation, P.O. Box 5825, Doha (Qatar); Collaboration: RoboNet Project and MiNDSTEp Consortium; OGLE Project; Spitzer Team; MOA Collaboration; KMTNet Modeling Team; and others

    2016-03-10

    We report the detection of a cold Neptune m{sub planet} = 21 ± 2 M{sub ⊕} orbiting a 0.38 M{sub ⊙} M dwarf lying 2.5–3.3 kpc toward the Galactic center as part of a campaign combining ground-based and Spitzer observations to measure the Galactic distribution of planets. This is the first time that the complex real-time protocols described by Yee et al., which aim to maximize planet sensitivity while maintaining sample integrity, have been carried out in practice. Multiple survey and follow up teams successfully combined their efforts within the framework of these protocols to detect this planet. This is the second planet in the Spitzer Galactic distribution sample. Both are in the near to mid-disk and are clearly not in the Galactic bulge.

  4. GALACTIC CEPHEIDS WITH SPITZER. II. SEARCH FOR EXTENDED INFRARED EMISSION

    International Nuclear Information System (INIS)

    Barmby, P.; Marengo, M.; Evans, N. R.; Huelsman, D.; Fazio, G. G.; Bono, G.; Su, K. Y. L.; Welch, D. L.

    2011-01-01

    A deep and detailed examination of 29 classical Cepheids with the Spitzer Space Telescope has revealed three stars with strong nearby extended emission detected in multiple bands which appears to be physically associated with the stars. RS Pup was already known to possess extended infrared emission, while the extended emission around the other two stars (S Mus and δ Cep) is newly discovered in our observations. Four other stars (GH Lup, l Car, T Mon, and X Cyg) show tentative evidence for extended infrared emission. An unusual elongated extended object next to SZ Tau appears to be a background or foreground object in a chance alignment with the Cepheid. The inferred mass-loss rate upper limits for S Mus and δ Cep are in the range from 10 -9 to 10 -8 M sun yr -1 , with the upper limit for RS Pup as high as 10 -6 M sun yr -1 . Mass loss during post-main-sequence evolution has been proposed as a resolution to the discrepancy between pulsational and dynamical masses of Cepheid variable stars: dust in the lost material would make itself known by the presence of an infrared bright nebula or unresolved infrared excess. The observed frequency of infrared circumstellar emission (<24%) and the mass-loss rate we estimate for our sources show that dusty mass loss can only account for part of the Cepheid mass-loss discrepancy. Nevertheless, our direct evidence that mass loss is active during the Cepheid phase is an important confirmation that these processes need to be included in evolutionary and pulsation models of these stars and should be taken into account in the calibration of the Cepheid distance scale.

  5. The X-ray properties of five galactic supernova remnants detected by the Spitzer glimpse survey

    International Nuclear Information System (INIS)

    Pannuti, Thomas G.; Moffitt, William P.; Rho, Jeonghee; Heinke, Craig O.

    2014-01-01

    We present a study of the X-ray properties of five Galactic supernova remnants (SNRs)—Kes 17 (G304.6+0.1), G311.5–0.3, G346.6–0.2, CTB 37A (G348.5+0.1), and G348.5–0.0—that were detected in the infrared by Reach et al. in an analysis of data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) that was conducted by the Spitzer Space Telescope. We present and analyze archival ASCA observations of Kes 17, G311.5–0.3, and G346.6–0.2, archival XMM-Newton observations of Kes 17, CTB 37A, and G348.5–0.0, and an archival Chandra observation of CTB 37A. All of the SNRs are clearly detected in the X-ray except possibly G348.5–0.0. Our study reveals that the four detected SNRs all feature center-filled X-ray morphologies and that the observed emission from these sources is thermal in all cases. We argue that these SNRs should be classified as mixed-morphology SNRs (MM SNRs); our study strengthens the correlation between MM SNRs and SNRs interacting with molecular clouds and suggests that the origin of MM SNRs may be due to the interactions between these SNRs and adjacent clouds. Our ASCA analysis of G311.5–0.3 reveals for the first time X-ray emission from this SNR: the X-ray emission is center-filled within the radio and infrared shells and thermal in nature (kT ∼ 0.98 keV), thus motivating its classification as an MM SNR. We find considerable spectral variations in the properties associated with the plasmas of the other X-ray-detected SNRs, such as a possible overabundance of magnesium in the plasma of Kes 17. Our new results also include the first detailed spatially resolved spectroscopic study of CTB 37A using Chandra as well as a spectroscopic study of the discrete X-ray source CXOU J171428.5–383601, which may be a neutron star associated with CTB 37A. Finally, we also estimate such properties as electron density n e , radiative age t rad and swept-up mass M X for each of the four X-ray-detected SNRs. Each of these values

  6. THE LUMINOSITIES OF PROTOSTARS IN THE SPITZER c2d AND GOULD BELT LEGACY CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, Michael M.; Arce, Hector G. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Allen, Lori E. [National Optical Astronomy Observatories, Tucson, AZ (United States); Evans II, Neal J.; Harvey, Paul M. [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Broekhoven-Fiene, Hannah; Matthews, Brenda C. [Herzberg Institute, National Research Council of Canada, 5071 W. Saanich Road, Victoria, BC V9E 2E7 (Canada); Chapman, Nicholas L. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Department of Physics and Astronomy, 2145 Sheridan Road, Evanston, IL 60208 (United States); Cieza, Lucas A. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Gutermuth, Robert A. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Hatchell, Jennifer [Astrophysics Group, Physics, University of Exeter, Exeter EX4 4QL (United Kingdom); Huard, Tracy L.; Miller, Jennifer F. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Kirk, Jason M. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Merin, Bruno [Herschel Science Centre, ESAC-ESA, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Peterson, Dawn E. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Spezzi, Loredana, E-mail: michael.dunham@yale.edu [European Southern Observatory (ESO), Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Muenchen (Germany)

    2013-04-15

    Motivated by the long-standing 'luminosity problem' in low-mass star formation whereby protostars are underluminous compared to theoretical expectations, we identify 230 protostars in 18 molecular clouds observed by two Spitzer Space Telescope Legacy surveys of nearby star-forming regions. We compile complete spectral energy distributions, calculate L{sub bol} for each source, and study the protostellar luminosity distribution. This distribution extends over three orders of magnitude, from 0.01 L{sub Sun} to 69 L{sub Sun }, and has a mean and median of 4.3 L{sub Sun} and 1.3 L{sub Sun }, respectively. The distributions are very similar for Class 0 and Class I sources except for an excess of low luminosity (L{sub bol} {approx}< 0.5 L{sub Sun }) Class I sources compared to Class 0. 100 out of the 230 protostars (43%) lack any available data in the far-infrared and submillimeter (70 {mu}m <{lambda} < 850 {mu}m) and have L{sub bol} underestimated by factors of 2.5 on average, and up to factors of 8-10 in extreme cases. Correcting these underestimates for each source individually once additional data becomes available will likely increase both the mean and median of the sample by 35%-40%. We discuss and compare our results to several recent theoretical studies of protostellar luminosities and show that our new results do not invalidate the conclusions of any of these studies. As these studies demonstrate that there is more than one plausible accretion scenario that can match observations, future attention is clearly needed. The better statistics provided by our increased data set should aid such future work.

  7. Enhancing the Legacy of Spitzer and Herschel with the MOSFIRE Deep Evolution Field Survey

    Science.gov (United States)

    Reddy, Naveen

    The next frontier for comprehensive galaxy surveys is the epoch at z~1.5-3.5, the peak of star formation and black hole activity. Despite the new windows that Spitzer and Herschel have opened up into the stellar and dust emission of distant galaxies and AGN during this key epoch, these studies have been limited by the lack of spectroscopic redshifts and the unknown physical conditions (e.g., metallicities, ionization) within the targeted galaxies. To realize the full potential of Spitzer and Herschel, we require a large spectroscopic survey that will: (a) efficiently assemble spectroscopic redshifts for large samples of galaxies at z=1.4-3.8; (b) yield the physical conditions, including the ionization and metallicities of these galaxies; and (c) easily obtain spectroscopic redshifts even for very dusty/confused galaxies. To this end, our team has been allocated a large program of 47 Keck nights with the multi-object near-IR spectrograph MOSFIRE to carry out the MOSFIRE Deep Evolution Field Survey (MOSDEF) in three of the Hubble CANDELS fields. MOSDEF will obtain rest-optical spectra of ~1500 galaxies at redshifts z=1.4-3.8, targeting many of the optical nebular emission lines and continuum features (e.g., [OII], [OIII], H-beta, H-alpha, [NII], [SII], 4000 Angstrom break, Ca H and K, and Mbg) that until now have been inaccessible for large samples of distant galaxies, but which are routinely used to measure the SFRs, dust attenuation, metal and gas content, and ionization and dynamical properties in nearby galaxies. MOSDEF spectroscopy provides a critical supporting role for the analysis of Spitzer and Herschel observations of distant galaxies. With this transformative dataset, we will perform the following analyses. First, we will use Spitzer and Herschel imaging, aided with spectroscopic redshifts from MOSDEF, to construct individual and mean dust SEDs for galaxies at redshifts 1.4formation and destruction processes. Our study will greatly enhance the scientific

  8. Spitzer Infrared Spectrograph Observations of the Galactic Center: Quantifying the Extreme Ultraviolet/Soft X-ray Fluxes

    Science.gov (United States)

    Simpson, Janet P.

    2018-04-01

    It has long been shown that the extreme ultraviolet spectrum of the ionizing stars of H II regions can be estimated by comparing the observed line emission to detailed models. In the Galactic Center (GC), however, previous observations have shown that the ionizing spectral energy distribution (SED) of the local photon field is strange, producing both very low excitation ionized gas (indicative of ionization by late O stars) and also widespread diffuse emission from atoms too highly ionized to be found in normal H II regions. This paper describes the analysis of all GC spectra taken by Spitzer's Infrared Spectrograph and downloaded from the Spitzer Heritage Archive. In it, H II region densities and abundances are described, and serendipitously discovered candidate planetary nebulae, compact shocks, and candidate young stellar objects are tabulated. Models were computed with Cloudy, using SEDs from Starburst99 plus additional X-rays, and compared to the observed mid-infrared forbidden and recombination lines. The ages inferred from the model fits do not agree with recent proposed star formation sequences (star formation in the GC occurring along streams of gas with density enhancements caused by close encounters with the black hole, Sgr A*), with Sgr B1, Sgr C, and the Arches Cluster being all about the same age, around 4.5 Myr old, with similar X-ray requirements. The fits for the Quintuplet Cluster appear to give a younger age, but that could be caused by higher-energy photons from shocks from stellar winds or from a supernova.

  9. LUMINOUS BURIED ACTIVE GALACTIC NUCLEI AS A FUNCTION OF GALAXY INFRARED LUMINOSITY REVEALED THROUGH SPITZER LOW-RESOLUTION INFRARED SPECTROSCOPY

    International Nuclear Information System (INIS)

    Imanishi, Masatoshi

    2009-01-01

    We present the results of Spitzer Infrared Spectrograph 5-35 μm low-resolution spectroscopic energy diagnostics of ultraluminous infrared galaxies (ULIRGs) at z> 0.15, classified optically as non-Seyferts. Based on the equivalent widths of polycyclic aromatic hydrocarbon emission and the optical depths of silicate dust absorption features, we searched for signatures of intrinsically luminous, but optically elusive, buried active galactic nuclei (AGNs) in these optically non-Seyfert ULIRGs. We then combined the results with those of non-Seyfert ULIRGs at z IR 12 L sun . We found that the energetic importance of buried AGNs clearly increases with galaxy infrared luminosity, becoming suddenly discernible in ULIRGs with L IR > 10 12 L sun . For ULIRGs with buried AGN signatures, a significant fraction of infrared luminosities can be accounted for by the detected buried AGN and modestly obscured (A V < 20 mag) starburst activity. The implied masses of spheroidal stellar components in galaxies for which buried AGNs become important roughly correspond to the value separating red massive and blue less-massive galaxies in the local universe. Our results may support the widely proposed AGN-feedback scenario as the origin of galaxy downsizing phenomena, where galaxies with currently larger stellar masses previously had higher AGN energetic contributions and star formation originating infrared luminosities, and have finished their major star formation more quickly, due to stronger AGN feedback.

  10. The SAGE-Spec Spitzer Legacy program: the life-cycle of dust and gas in the Large Magellanic Cloud. Point source classification - III

    Science.gov (United States)

    Jones, O. C.; Woods, P. M.; Kemper, F.; Kraemer, K. E.; Sloan, G. C.; Srinivasan, S.; Oliveira, J. M.; van Loon, J. Th.; Boyer, M. L.; Sargent, B. A.; McDonald, I.; Meixner, M.; Zijlstra, A. A.; Ruffle, P. M. E.; Lagadec, E.; Pauly, T.; Sewiło, M.; Clayton, G. C.; Volk, K.

    2017-09-01

    The Infrared Spectrograph (IRS) on the Spitzer Space Telescope observed nearly 800 point sources in the Large Magellanic Cloud (LMC), taking over 1000 spectra. 197 of these targets were observed as part of the SAGE-Spec Spitzer Legacy program; the remainder are from a variety of different calibration, guaranteed time and open time projects. We classify these point sources into types according to their infrared spectral features, continuum and spectral energy distribution shape, bolometric luminosity, cluster membership and variability information, using a decision-tree classification method. We then refine the classification using supplementary information from the astrophysical literature. We find that our IRS sample is comprised substantially of YSO and H II regions, post-main-sequence low-mass stars: (post-)asymptotic giant branch stars and planetary nebulae and massive stars including several rare evolutionary types. Two supernova remnants, a nova and several background galaxies were also observed. We use these classifications to improve our understanding of the stellar populations in the LMC, study the composition and characteristics of dust species in a variety of LMC objects, and to verify the photometric classification methods used by mid-IR surveys. We discover that some widely used catalogues of objects contain considerable contamination and others are missing sources in our sample.

  11. Black Hole Masses for Type I Active Galactic Nuclei in the Chandra Cosmos Legacy Survey

    Science.gov (United States)

    Nagaraj, Gautam; Fornasini, Francesca; Civano, Francesca Maria

    2018-01-01

    Tight local relations between SMBH masses and galaxy properties have established the fundamental connection between SMBHs and their host galaxies. However, in order to better understand the coevolution of SMBHs and their host galaxies over cosmic time, we need measurements of black hole masses, AGN luminosities, and galaxy stellar masses from sizable samples of AGN covering lower luminosities than the brightest quasars spanning a wide redshift range. In this study, we report masses of the SMBHs of 224 Type I AGNs from the Chandra COSMOS Legacy Survey as determined by the line widths of Mg II 2798, Hb 4862, and Ha 6564 via scaling relations derived from reverberation mapping. Preliminary comparison with host galaxy luminosities and stellar masses suggests an increase in Eddington ratio with redshift, consistent with previous studies. In addition, our derived SMBH masses fall above the local AGN MBH--M* (galactic stellar mass) relation from Reines & Volonteri (2015), but it is still not clear whether this results from redshift evolution of the MBH--M* relation or from the incompleteness of the spectroscopic surveys available. The SAO REU program is funded by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant AST-1659473, and by the Smithsonian Institution.

  12. THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS. VIII. PRELIMINARY PUBLIC CATALOG RELEASE

    Energy Technology Data Exchange (ETDEWEB)

    Soto, M.; Bellini, A.; Anderson, J.; Van der Marel, R. P.; Brown, T. M. [Space Telescope Science Institute, San Martin Drive 3700, Baltimore, MD 21218 (United States); Piotto, G.; Granata, V.; Ortolani, S.; Nardiello, D. [Dipartimento di Fisica e Astronomia Galileo Galilei, Università di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova (Italy); Bedin, L. R. [INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Milone, A. P. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT, 2611 (Australia); Cool, A. M. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); King, I. R. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Sarajedini, A. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Cassisi, S. [Osservatorio Astronomico di Teramo, Via Mentore Maggini s.n.c., I-64100 Teramo (Italy); Aparicio, A.; Hidalgo, S., E-mail: mario.soto@uda.cl [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Canary Islands (Spain)

    2017-01-01

    The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GO-13297) has been specifically designed to complement the existing F606W and F814W observations of the Advanced Camera for Surveys (ACS) Globular Cluster Survey (GO-10775) by observing the most accessible 47 of the previous survey’s 65 clusters in three WFC3/UVIS filters F275W, F336W, and F438W. The new survey also adds super-solar metallicity open cluster NGC 6791 to increase the metallicity diversity. The combined survey provides a homogeneous 5-band data set that can be used to pursue a broad range of scientific investigations. In particular, the chosen UV filters allow the identification of multiple stellar populations by targeting the regions of the spectrum that are sensitive to abundance variations in C, N, and O. In order to provide the community with uniform preliminary catalogs, we have devised an automated procedure that performs high-quality photometry on the new UV observations (along with similar observations of seven other programs in the archive). This procedure finds and measures the potential sources on each individual exposure using library point-spread functions and cross-correlates these observations with the original ACS-Survey catalog. The catalog of 57 clusters we publish here will be useful to identify stars in the different stellar populations, in particular for spectroscopic follow-up. Eventually, we will construct a more sophisticated catalog and artificial-star tests based on an optimal reduction of the UV survey data, but the catalogs presented here give the community the chance to make early use of this HST Treasury survey.

  13. Legacy ExtraGalactic UV Survey with The Hubble Space Telescope: Stellar Cluster Catalogs and First Insights Into Cluster Formation and Evolution in NGC 628

    NARCIS (Netherlands)

    Adamo, A.; Ryon, J.E.; Messa, M.; Kim, H.; Grasha, K.; Cook, D.O.; Calzetti, D.; Lee, J.C.; Whitmore, B.C.; Elmegreen, B.G.; Ubeda, L.; Smith, L.J.; Bright, S.N.; Runnholm, A.; Andrews, J.E.; Fumagalli, M.; Gouliermis, D.A.; Kahre, L.; Nair, P.; Thilker, D.; Walterbos, R.; Wofford, A.; Aloisi, A.; Ashworth, G.; Brown, T.M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G.C.; Dale, D.A.; de Mink, S.E.; Dobbs, C.; Elmegreen, D.M.; Evans, A.S.; Gallagher III, J.S.; Grebel, E.K.; Herrero, A.; Hunter, D.A.; Johnson, K.E.; Kennicutt, R.C.; Krumholz, M.R.; Lennon, D.; Levay, K.; Martin, C.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M.W.; Sabbi, E.; Sacchi, E.; Schaerer, D.; Schiminovich, D.; Shabani, F.; Tosi, M.; Van Dyk, S.D.; Zackrisson, E.

    2017-01-01

    We report the large effort that is producing comprehensive high-level young star cluster (YSC) catalogs for a significant fraction of galaxies observed with the Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. We present the methodology developed to extract cluster positions, verify

  14. A 24 μm point source catalog of the galactic plane from Spitzer/MIPSGAL

    International Nuclear Information System (INIS)

    Gutermuth, Robert A.; Heyer, Mark

    2015-01-01

    In this contribution, we describe the applied methods to construct a 24 μm based point source catalog derived from the image data of the MIPSGAL 24 μm Galactic Plane Survey and the corresponding data products. The high quality catalog product contains 933,818 sources, with a total of 1,353,228 in the full archive catalog. The source tables include positional and photometric information derived from the 24 μm images, source quality and confusion flags, and counterpart photometry from matched 2MASS, GLIMPSE, and WISE point sources. Completeness decay data cubes are constructed at 1′ angular resolution that describe the varying background levels over the MIPSGAL field and the ability to extract sources of a given magnitude from this background. The completeness decay cubes are included in the set of data products. We present the results of our efforts to verify the astrometric and photometric calibration of the catalog, and present several analyses of minor anomalies in these measurements to justify adopted mitigation strategies.

  15. A 24 μm Point Source Catalog of the Galactic Plane from Spitzer/MIPSGAL

    Science.gov (United States)

    Gutermuth, Robert A.; Heyer, Mark

    2015-02-01

    In this contribution, we describe the applied methods to construct a 24 μm based point source catalog derived from the image data of the MIPSGAL 24 μm Galactic Plane Survey and the corresponding data products. The high quality catalog product contains 933,818 sources, with a total of 1,353,228 in the full archive catalog. The source tables include positional and photometric information derived from the 24 μm images, source quality and confusion flags, and counterpart photometry from matched 2MASS, GLIMPSE, and WISE point sources. Completeness decay data cubes are constructed at 1‧ angular resolution that describe the varying background levels over the MIPSGAL field and the ability to extract sources of a given magnitude from this background. The completeness decay cubes are included in the set of data products. We present the results of our efforts to verify the astrometric and photometric calibration of the catalog, and present several analyses of minor anomalies in these measurements to justify adopted mitigation strategies.

  16. Evidence for Infrared-faint Radio Sources as z > 1 Radio-loud Active Galactic Nuclei

    Science.gov (United States)

    Huynh, Minh T.; Norris, Ray P.; Siana, Brian; Middelberg, Enno

    2010-02-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6-70 μm) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the spectral energy distribution of these objects shows that they are consistent with high-redshift (z >~ 1) active galactic nuclei.

  17. The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters - XII. The RGB bumps of multiple stellar populations

    Science.gov (United States)

    Lagioia, E. P.; Milone, A. P.; Marino, A. F.; Cassisi, S.; Aparicio, A. J.; Piotto, G.; Anderson, J.; Barbuy, B.; Bedin, L. R.; Bellini, A.; Brown, T.; D'Antona, F.; Nardiello, D.; Ortolani, S.; Pietrinferni, A.; Renzini, A.; Salaris, M.; Sarajedini, A.; van der Marel, R.; Vesperini, E.

    2018-04-01

    The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters is providing a major breakthrough in our knowledge of globular clusters (GCs) and their stellar populations. Among the main results, we discovered that all the studied GCs host two main discrete groups consisting of first generation (1G) and second generation (2G) stars. We exploit the multiwavelength photometry from this project to investigate, for the first time, the Red Giant Branch Bump (RGBB) of the two generations in a large sample of GCs. We identified, with high statistical significance, the RGBB of 1G and 2G stars in 26 GCs and found that their magnitude separation as a function of the filter wavelength follows comparable trends. The comparison of observations to synthetic spectra reveals that the RGBB luminosity depends on the stellar chemical composition and that the 2G RGBB is consistent with stars enhanced in He and N and depleted in C and O with respect to 1G stars. For metal-poor GCs the 1G and 2G RGBB relative luminosity in optical bands mostly depends on helium content, Y. We used the RGBB observations in F606W and F814W bands to infer the relative helium abundance of 1G and 2G stars in 18 GCs, finding an average helium enhancement ΔY = 0.011 ± 0.002 of 2G stars with respect to 1G stars. This is the first determination of the average difference in helium abundance of multiple populations in a large number of clusters and provides a lower limit to the maximum internal variation of helium in GCs.

  18. Spitzer Parallax of OGLE-2015-BLG-0966

    DEFF Research Database (Denmark)

    Street, R. A.; Udalski, A.; Calchi Novati, S.

    2016-01-01

    We report the detection of a cold Neptune mplanet = 21 ± 2 M⊕ orbiting a 0.38 M⊙ M dwarf lying 2.5-3.3 kpc toward the Galactic center as part of a campaign combining ground-based and Spitzer observations to measure the Galactic distribution of planets. This is the first time that the complex real...

  19. Spitzer Spies Spectacular Sombrero

    Science.gov (United States)

    2005-01-01

    camera. The survey is one of the six Spitzer Legacy Science projects, designed to reveal how stars are formed in different types of galaxies, and to provide an atlas of galaxy images and spectra for future archival investigations. The Sombrero is one of 75 galaxies being observed by the survey team. In this image, blue-cyan corresponds to the Hubble visible-light view, while the Spitzer 3.6-4.5 micron light is green and 8.0 micron light is red. Starlight in this Spitzer image (measured at 3.6 microns) has been subtracted from the 8-micron image to enhance the visibility of the dust features. In figure 3, NASA's Hubble Space Telescope has trained its sharp eye on one of the universe's most stately and photogenic galaxies, Messier 104. The galaxy's hallmark is a brilliant white, bulbous core encircled by the thick dust lanes comprising the spiral structure of the galaxy. As seen from Earth, the galaxy is tilted nearly edge-on. We view it from just six degrees north of its equatorial plane. This brilliant galaxy was named the Sombrero because in visible light it resembles a broad rimmed and high-topped Mexican hat. M104 is just beyond the limit of the naked eye, but is easily seen through small telescopes. It lies at the southern edge of the rich Virgo cluster of galaxies. It is one of the most massive objects in that group, equivalent to 800 billion suns. The galaxy is 50,000 light-years across and is located 28 million light-years from Earth. Hubble easily resolves M104's rich system of 2,000 globular clusters-believed to be 10 times as many as orbit our Milky Way galaxy. The ages of the clusters are similar to those of the clusters in the Milky Way, ranging from 10-13 billion years. A smaller disk is embedded in the bright core of M104, and is tilted relative to the large disk. X-ray emission hints that there is material falling into the compact core, where a black hole as massive as 1 billion suns resides. The Hubble Heritage Team took these observations in May

  20. THE SPITZER MID-INFRARED ACTIVE GALACTIC NUCLEUS SURVEY. I. OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF OBSCURED CANDIDATES AND NORMAL ACTIVE GALACTIC NUCLEI SELECTED IN THE MID-INFRARED

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Ridgway, S. E. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Gates, E. L. [UCO/Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Nielsen, D. M. [Department of Astronomy, University of Wisconsin, 475 N. Charter Street, Madison, WI 53706 (United States); Petric, A. O. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Sajina, A. [Department of Physics and Astronomy, Tuffs University, 212 College Avenue, Medford, MA 02155 (United States); Urrutia, T. [Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Cox Drews, S. [946 Mangrove Avenue 102, Sunnyvale, CA 94086 (United States); Harrison, C. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Seymour, N. [CSIRO, P.O. Box 76, Epping, NSW 1710 (Australia); Storrie-Lombardi, L. J. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2013-10-01

    We present the results of a program of optical and near-infrared spectroscopic follow-up of candidate active galactic nuclei (AGNs) selected in the mid-infrared. This survey selects both normal and obscured AGNs closely matched in luminosity across a wide range, from Seyfert galaxies with bolometric luminosities L {sub bol} ∼ 10{sup 10} L {sub ☉} to highly luminous quasars (L {sub bol} ∼ 10{sup 14} L {sub ☉}), all with redshifts ranging from 0 to 4.3. Samples of candidate AGNs were selected with mid-infrared color cuts at several different 24 μm flux density limits to ensure a range of luminosities at a given redshift. The survey consists of 786 candidate AGNs and quasars, of which 672 have spectroscopic redshifts and classifications. Of these, 137 (20%) are type 1 AGNs with blue continua, 294 (44%) are type 2 objects with extinctions A{sub V} ∼> 5 toward their AGNs, 96 (14%) are AGNs with lower extinctions (A{sub V} ∼ 1), and 145 (22%) have redshifts, but no clear signs of AGN activity in their spectra. Of the survey objects 50% have L {sub bol} > 10{sup 12} L {sub ☉}, in the quasar regime. We present composite spectra for type 2 quasars and objects with no signs of AGN activity in their spectra. We also discuss the mid-infrared—emission-line luminosity correlation and present the results of cross correlations with serendipitous X-ray and radio sources. The results show that: (1) obscured objects dominate the overall AGN population, (2) mid-infrared selected AGN candidates exist which lack AGN signatures in their optical spectra but have AGN-like X-ray or radio counterparts, and (3) X-ray and optical classifications of obscured and unobscured AGNs often differ.

  1. Legacy ExtraGalactic UV Survey with The Hubble Space Telescope: Stellar Cluster Catalogs and First Insights Into Cluster Formation and Evolution in NGC 628

    Science.gov (United States)

    Adamo, A.; Ryon, J. E.; Messa, M.; Kim, H.; Grasha, K.; Cook, D. O.; Calzetti, D.; Lee, J. C.; Whitmore, B. C.; Elmegreen, B. G.; Ubeda, L.; Smith, L. J.; Bright, S. N.; Runnholm, A.; Andrews, J. E.; Fumagalli, M.; Gouliermis, D. A.; Kahre, L.; Nair, P.; Thilker, D.; Walterbos, R.; Wofford, A.; Aloisi, A.; Ashworth, G.; Brown, T. M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G. C.; Dale, D. A.; de Mink, S. E.; Dobbs, C.; Elmegreen, D. M.; Evans, A. S.; Gallagher, J. S., III; Grebel, E. K.; Herrero, A.; Hunter, D. A.; Johnson, K. E.; Kennicutt, R. C.; Krumholz, M. R.; Lennon, D.; Levay, K.; Martin, C.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M. W.; Sabbi, E.; Sacchi, E.; Schaerer, D.; Schiminovich, D.; Shabani, F.; Tosi, M.; Van Dyk, S. D.; Zackrisson, E.

    2017-06-01

    We report the large effort that is producing comprehensive high-level young star cluster (YSC) catalogs for a significant fraction of galaxies observed with the Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. We present the methodology developed to extract cluster positions, verify their genuine nature, produce multiband photometry (from NUV to NIR), and derive their physical properties via spectral energy distribution fitting analyses. We use the nearby spiral galaxy NGC 628 as a test case for demonstrating the impact that LEGUS will have on our understanding of the formation and evolution of YSCs and compact stellar associations within their host galaxy. Our analysis of the cluster luminosity function from the UV to the NIR finds a steepening at the bright end and at all wavelengths suggesting a dearth of luminous clusters. The cluster mass function of NGC 628 is consistent with a power-law distribution of slopes ˜ -2 and a truncation of a few times 105 {M}⊙ . After their formation, YSCs and compact associations follow different evolutionary paths. YSCs survive for a longer time frame, confirming their being potentially bound systems. Associations disappear on timescales comparable to hierarchically organized star-forming regions, suggesting that they are expanding systems. We find mass-independent cluster disruption in the inner region of NGC 628, while in the outer part of the galaxy there is little or no disruption. We observe faster disruption rates for low mass (≤104 {M}⊙ ) clusters, suggesting that a mass-dependent component is necessary to fully describe the YSC disruption process in NGC 628. Based on observations obtained 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.

  2. Applications of machine-learning algorithms for infrared colour selection of Galactic Wolf-Rayet stars

    Science.gov (United States)

    Morello, Giuseppe; Morris, P. W.; Van Dyk, S. D.; Marston, A. P.; Mauerhan, J. C.

    2018-01-01

    We have investigated and applied machine-learning algorithms for infrared colour selection of Galactic Wolf-Rayet (WR) candidates. Objects taken from the Spitzer Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE) catalogue of the infrared objects in the Galactic plane can be classified into different stellar populations based on the colours inferred from their broad-band photometric magnitudes [J, H and Ks from 2 Micron All Sky Survey (2MASS), and the four Spitzer/IRAC bands]. The algorithms tested in this pilot study are variants of the k-nearest neighbours approach, which is ideal for exploratory studies of classification problems where interrelations between variables and classes are complicated. The aims of this study are (1) to provide an automated tool to select reliable WR candidates and potentially other classes of objects, (2) to measure the efficiency of infrared colour selection at performing these tasks and (3) to lay the groundwork for statistically inferring the total number of WR stars in our Galaxy. We report the performance results obtained over a set of known objects and selected candidates for which we have carried out follow-up spectroscopic observations, and confirm the discovery of four new WR stars.

  3. NEWLY IDENTIFIED EXTENDED GREEN OBJECTS (EGOs) FROM THE SPITZER GLIMPSE II SURVEY. I. CATALOG

    International Nuclear Information System (INIS)

    Chen, Xi; Gan, Cong-Gui; Shen, Zhi-Qiang; Ellingsen, Simon P.; Titmarsh, Anita; He, Jin-Hua

    2013-01-01

    We have produced a catalog containing 98 newly identified massive young stellar object (MYSO) candidates associated with ongoing outflows (known as extended green objects, or EGOs). These have been identified from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) II data set and our new identifications increase the number of known EGOs to ∼400 in our Galaxy, adding to the ∼300 previously identified EGOs reported by Cyganowski et al. from the GLIMPSE I survey. The high detection rate (∼70%) of 95 GHz class I methanol masers achieved in a survey toward 57 of these new EGOs with the Mopra 22 m radio telescope demonstrates that the new EGOs are associated with outflows. Investigations of the mid-infrared properties and physical associations with other star formation tracers (e.g., infrared dark clouds, class I and II methanol masers, and millimeter Bolocam Galactic Plane Survey sources) reveal that the newly identified EGOs are very similar in nature to those in the sample of Cyganowski et al. All of the observational evidence supports the hypothesis that EGOs correspond to MYSOs at the earliest evolutionary stage, with ongoing outflow activity, and active rapid accretion.

  4. Spitzer Telemetry Processing System

    Science.gov (United States)

    Stanboli, Alice; Martinez, Elmain M.; McAuley, James M.

    2013-01-01

    The Spitzer Telemetry Processing System (SirtfTlmProc) was designed to address objectives of JPL's Multi-mission Image Processing Lab (MIPL) in processing spacecraft telemetry and distributing the resulting data to the science community. To minimize costs and maximize operability, the software design focused on automated error recovery, performance, and information management. The system processes telemetry from the Spitzer spacecraft and delivers Level 0 products to the Spitzer Science Center. SirtfTlmProc is a unique system with automated error notification and recovery, with a real-time continuous service that can go quiescent after periods of inactivity. The software can process 2 GB of telemetry and deliver Level 0 science products to the end user in four hours. It provides analysis tools so the operator can manage the system and troubleshoot problems. It automates telemetry processing in order to reduce staffing costs.

  5. IPHAS A-TYPE STARS WITH MID-INFRARED EXCESSES IN SPITZER SURVEYS

    International Nuclear Information System (INIS)

    Hales, Antonio S.; Barlow, Michael J.; Drew, Janet E.; Unruh, Yvonne C.; Greimel, Robert; Irwin, Michael J.; Gonzalez-Solares, Eduardo

    2009-01-01

    We have identified 17 A-type stars in the Galactic Plane that have mid-infrared (mid-IR) excesses at 8 μm. From observed colors in the (r' - Hα) - (r' - i') plane, we first identified 23,050 early A-type main-sequence (MS) star candidates in the Isaac Newton Photometric H-Alpha Survey (IPHAS) point source database that are located in Spitzer Galactic Legacy Mid-Plane Survey Extraordinaire Galactic plane fields. Imposing the requirement that they be detected in all seven Two Micron All Sky Survey and Infrared Astronomical Satellite bands led to a sample of 2692 candidate A-type stars with fully sampled 0.6 to 8 μm spectral energy distributions (SEDs). Optical classification spectra of 18 of the IPHAS candidate A-type MS stars showed that all but one could be well fitted using MS A-type templates, with the other being an A-type supergiant. Out of the 2692 A-type candidates 17 (0.6%) were found to have 8 μm excesses above the expected photospheric values. Taking into account non-A-Type contamination estimates, the 8 μm excess fraction is adjusted to ∼0.7%. The distances to these sources range from 0.7 to 2.5 kpc. Only 10 out of the 17 excess stars had been covered by Spitzer MIPSGAL survey fields, of which five had detectable excesses at 24 μm. For sources with excesses detected in at least two mid-IR wavelength bands, blackbody fits to the excess SEDs yielded temperatures ranging from 270 to 650 K, and bolometric luminosity ratios L IR /L * from 2.2 x 10 -3 - 1.9 x 10 -2 , with a mean value of 7.9 x 10 -3 (these bolometric luminosities are lower limits as cold dust is not detectable by this survey). Both the presence of mid-IR excesses and the derived bolometric luminosity ratios are consistent with many of these systems being in the planet-building transition phase between the early protoplanetary disk phase and the later debris disk phase.

  6. THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS. VII. IMPLICATIONS FROM THE NEARLY UNIVERSAL NATURE OF HORIZONTAL BRANCH DISCONTINUITIES

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T. M.; Bellini, A.; Anderson, J. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Cassisi, S.; Pietrinferni, A. [INAF-Osservatorio Astronomico di Teramo, Via Mentore Maggini s.n.c., I-64100 Teramo (Italy); D’Antona, F. [INAF-Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monteporzio Catone, Roma (Italy); Salaris, M. [Astrophysics Research Institute,Liverpool John Moores University, Liverpool Science Park, IC2 Building, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Milone, A. P. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT, 2611 (Australia); Dalessandro, E. [Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Viale Berti Pichat 6/2, I-40127 Bologna (Italy); Piotto, G.; Ortolani, S.; Nardiello, D. [Dipartimento di Fisica e Astronomia “Galileo Galilei,”Università di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova (Italy); Renzini, A.; Bedin, L. R. [INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Sweigart, A. V. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sarajedini, A. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Aparicio, A., E-mail: tbrown@stsci.edu, E-mail: jayander@stsci, E-mail: bellini@stsci.edu, E-mail: cassisi@oa-teramo.inaf.it, E-mail: pietrinferni@oa-teramo.inaf.it, E-mail: dantona@oa-roma.inaf.it, E-mail: M.Salaris@ljmu.ac.uk, E-mail: milone@mso.anu.edu.au [Instituto de Astrofísica de Canarias. Calle Vía Láctea s/n. E38200 — La Laguna, Tenerife, Canary Islands (Spain)

    2016-05-01

    The UV-initiative Hubble Space Telescope Treasury survey of Galactic globular clusters provides a new window into the phenomena that shape the morphological features of the horizontal branch (HB). Using this large and homogeneous catalog of UV and blue photometry, we demonstrate that the HB exhibits discontinuities that are remarkably consistent in color (effective temperature). This consistency is apparent even among some of the most massive clusters hosting multiple distinct sub-populations (such as NGC 2808, ω Cen, and NGC 6715), demonstrating that these phenomena are primarily driven by atmospheric physics that is independent of the underlying population properties. However, inconsistencies arise in the metal-rich clusters NGC 6388 and NGC 6441, where the discontinuity within the blue HB (BHB) distribution shifts ∼1000–2000 K hotter. We demonstrate that this shift is likely due to a large helium enhancement in the BHB stars of these clusters, which in turn affects the surface convection and evolution of such stars. Our survey also increases the number of Galactic globular clusters known to host blue-hook stars (also known as late hot flashers) from 6 to 23 clusters. These clusters are biased toward the bright end of the globular cluster luminosity function, confirming that blue-hook stars tend to form in the most massive clusters with significant self-enrichment.

  7. Scheduling Spitzer: The SIRPASS Story

    Science.gov (United States)

    Mittman, David S.; Hawkins, Robert

    2013-01-01

    NASA's Spitzer Space Telescope was launched on August 25, 2003 from Florida's Cape Canaveral Air Force Base. Drifting in a unique Earth-trailing orbit around the Sun, Spitzer sees an optically invisible universe dominated by dust and stars. Since 1997, the Spitzer Integrated Resource Planning and Scheduling System (SIRPASS) has helped produce spacecraft activity plans for the Spitzer Space Telescope. SIRPASS is used by members of the Observatory Planning and Scheduling Team to plan, schedule and sequence the Telescope from data made available to them from the science and engineering community. Because of the volume of data that needs to be scheduled, SIRPASS offers a variety of automated assistants to aid in this task. This paper will describe the functional elements of the SIRPASS software system -- emphasizing the role that automation plays in the system -- and will highlight lessons learned for the software developer from a decade of Spitzer Space Telescope operations experience.

  8. The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters - XIV. Multiple stellar populations within M 15 and their radial distribution.

    Science.gov (United States)

    Nardiello, D.; Milone, A. P.; Piotto, G.; Anderson, J.; Bedin, L. R.; Bellini, A.; Cassisi, S.; Libralato, M.; Marino, A. F.

    2018-03-01

    In the context of the Hubble Space Telescope UV Survey of Galactic Globular Clusters (GCs), we derived high-precision, multi-band photometry to investigate the multiple stellar populations in the massive and metal-poor GC M 15. By creating for red-giant branch (RGB) stars of the cluster a `chromosome map', which is a pseudo two-colour diagram made with appropriate combination of F275W, F336W, F438W, and F814W magnitudes, we revealed colour spreads around two of the three already known stellar populations. These spreads cannot be produced by photometric errors alone and could hide the existence of (two) additional populations. This discovery increases the complexity of the multiple-population phenomenon in M 15. Our analysis shows that M 15 exhibits a faint sub-giant branch (SGB), which is also detected in colour-magnitude diagrams (CMDs) made with optical magnitudes only. This poorly-populated SGB includes about 5% of the total number of SGB stars and evolves into a red RGB in the mF336W vs. mF336W - mF814W CMD, suggesting that M 15 belongs to the class of Type II GCs. We measured the relative number of stars in each population at various radial distances from the cluster centre, showing that all of these populations share the same radial distribution within statistic uncertainties. These new findings are discussed in the context of the formation and evolution scenarios of the multiple populations.

  9. INTERSTELLAR EXTINCTION LAW TOWARD THE GALACTIC CENTER III: J, H, KS BANDS IN THE 2MASS AND THE MKO SYSTEMS, AND 3.6, 4.5, 5.8, 8.0 μm IN THE SPITZER/IRAC SYSTEM

    International Nuclear Information System (INIS)

    Nishiyama, Shogo; Nagata, Tetsuya; Tamura, Motohide; Hatano, Hirofumi; Kato, Daisuke; Tanabe, Toshihiko; Sugitani, Koji

    2009-01-01

    We have determined interstellar extinction law toward the Galactic center (GC) at the wavelength from 1.2 to 8.0 μm, using point sources detected in the IRSF/SIRIUS near-infrared (NIR) survey and those in the Two Micron All Sky Survey (2MASS) and Spitzer/IRAC/GLIMPSE II catalogs. The central region |l | ∼ 0 0 and |b | ∼ 0 0 has been surveyed in the J, H, and K S bands with the IRSF telescope and the SIRIUS camera whose filters are similar to the Mauna Kea Observatories (MKO) NIR photometric system. Combined with the GLIMPSE II point source catalog, we made K S versus K S - λ color-magnitude diagrams (CMDs) where λ=3.6, 4.5, 5.8, and 8.0 μm. The K S magnitudes of bulge red clump stars and the K S - λ colors of red giant branches are used as a tracer of the reddening vector in the CMDs. From these magnitudes and colors, we have obtained the ratios of total-to-selective extinction A K S /E K S -λ for the four IRAC bands. Combined with A λ /A K S for the J and H bands derived by Nishiyama et al., we obtain A J :A H :A K S :A [3.6] :A [4.5] :A [5.8] :A [8.0] = 3.02:1.73:1:0.50:0.39:0.36:0.43 for the line of sight toward the GC. This confirms the flattening of the extinction curve at λ ∼> 3 μm from a simple extrapolation of the power-law extinction at shorter wavelengths, in accordance with recent studies. The extinction law in the 2MASS J, H, and K S bands has also been calculated, and good agreement with that in the MKO system is found. Thus, it is established that the extinction in the wavelength range of J, H, and K S is well fitted by a power law of steep decrease A λ ∝ λ -2.0 toward the GC. In nearby molecular clouds and diffuse interstellar medium, the lack of reliable measurements of the total-to-selective extinction ratios hampers unambiguous determination of the extinction law; however, observational results toward these lines of sight cannot be reconciled with a single extinction law.

  10. Legacy question

    International Nuclear Information System (INIS)

    Healy, J.W.

    1977-01-01

    The legacy question discussed refers to the definition of appropriate actions in this generation to provide a world that will allow future generations to use the earth without excessive limitations caused by our use and disposal of potentially hazardous materials

  11. c2d Spitzer IRS spectra of embedded low-mass young stars : gas-phase emission lines

    NARCIS (Netherlands)

    Lahuis, F.; van Dishoeck, E. F.; Jorgensen, J. K.; Blake, G. A.; Evans, N. J.

    Context. A survey of mid-infrared gas-phase emission lines of H(2), H(2)O and various atoms toward a sample of 43 embedded low-mass young stars in nearby star-forming regions is presented. The sources are selected from the Spitzer "Cores to Disks" (c2d) legacy program. Aims. The environment of

  12. Spitzer Reveals Stellar 'Family Tree'

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] High resolution poster version Generations of stars can be seen in this new infrared portrait from NASA's Spitzer Space Telescope. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Younger stars line the rims of the cavities, and some can be seen as pink dots at the tips of the elephant-trunk-like pillars. The white knotty areas are where the youngest stars are forming. Red shows heated dust that pervades the region's cavities, while green highlights dense clouds. W5 spans an area of sky equivalent to four full moons and is about 6,500 light-years away in the constellation Cassiopeia. The Spitzer picture was taken over a period of 24 hours. Like other massive star-forming regions, such as Orion and Carina, W5 contains large cavities that were carved out by radiation and winds from the region's most massive stars. According to the theory of triggered star-formation, the carving out of these cavities pushes gas together, causing it to ignite into successive generations of new stars. This image contains some of the best evidence yet for the triggered star-formation theory. Scientists analyzing the photo have been able to show that the ages of the stars become progressively and systematically younger with distance from the center of the cavities. This is a three-color composite showing infrared observations from two Spitzer instruments. Blue represents 3.6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer.

  13. Where Galactic Snakes Live

    Science.gov (United States)

    2006-01-01

    This infrared image from NASA's Spitzer Space Telescope shows what astronomers are referring to as a 'snake' (upper left) and its surrounding stormy environment. The sinuous object is actually the core of a thick, sooty cloud large enough to swallow dozens of solar systems. In fact, astronomers say the 'snake's belly' may be harboring beastly stars in the process of forming. The galactic creepy crawler to the right of the snake is another thick cloud core, in which additional burgeoning massive stars might be lurking. The colorful regions below the two cloud cores are less dense cloud material, in which dust has been heated by starlight and glows with infrared light. Yellow and orange dots throughout the image are monstrous developing stars; the red star on the 'belly' of the snake is 20 to 50 times as massive as our sun. The blue dots are foreground stars. The red ball at the bottom left is a 'supernova remnant,' the remains of massive star that died in a fiery blast. Astronomers speculate that radiation and winds from the star before it died, in addition to a shock wave created when it exploded, might have played a role in creating the snake. Spitzer was able to spot the two black cloud cores using its heat-seeking infrared vision. The objects are hiding in the dusty plane of our Milky Way galaxy, invisible to optical telescopes. Because their heat, or infrared light, can sneak through the dust, they first showed up in infrared images from past missions. The cloud cores are so thick with dust that if you were to somehow transport yourself into the middle of them, you would see nothing but black, not even a star in the sky. Now, that's spooky! Spitzer's new view of the region provides the best look yet at the massive embryonic stars hiding inside the snake. Astronomers say these observations will ultimately help them better understand how massive stars form. By studying the clustering and range of masses of the stellar embryos, they hope to determine if the stars

  14. Pathway to the galactic distribution of planets

    DEFF Research Database (Denmark)

    Novati, S. Calchi; Gould, A.; Udalski, A.

    2015-01-01

    distance estimates for each lens, with error bars that are small compared to the Sun's Galactocentric distance. The ensemble therefore yields a well-defined cumulative distribution of lens distances. In principle it is possible to compare this distribution against a set of planets detected in the same...... experiment in order to measure the Galactic distribution of planets. Since these Spitzer observations yielded only one planet, this is not yet possible in practice. However, it will become possible as larger samples are accumulated....

  15. Exoplanet Characterization With Spitzer Eclipses

    Science.gov (United States)

    Harrington, Joseph

    We will analyze our existing Spitzer eclipse data for 11 exoplanets (GJ 436b, WASP-8b, WASP-29b, WASP-11b, TrES-1, WASP-34b, WASP-43b, HD 209458b, HAT-P-30b, HAT-P-13b, and WASP-12b) along with all other Spitzer eclipse and transit data for these systems (723 hours of total data). In combination with transit results, these measurements reveal the surface fluxes emitted by the planets' atmospheres in the six Spitzer bandpasses (3.6, 4.5, 5.8, 8.0, 16, and 24 1-4m), as well as orbital eccentricity and in a few cases possibly even precession rate. The fluxes, in turn, can constrain atmospheric composition and thermal profiles. We propose here to analyze data for these planets using Monte Carlo-driven, radiative-transfer, model-fitting codes; to conduct aggregate analyses; and to develop and share statistical modeling tools. Secondary eclipses provide us with a unique way to characterize exoplanetary atmospheres. Since other techniques like spectroscopy divide the planetary signal into many channels, they require very high signal-to-noise ratio (S/N) and are only possible for a few planets. Broadband eclipse photometry is thus the only technique that can measure dozens of atmospheres and identify the mechanisms that cause planets at a given irradiation level to behave so differently from one another. Until JWST becomes available, the broad variety of Spitzer data that we already have in hand, along with observations from the Hubble Space Telescope and possibly SOFIA, are our best way to understand the wide diversity of exoplanetary atmospheres. Since 2010, the team has produced six papers from a new, highly modular pipeline that implements optimal methods for analysis of Spitzer photometric time series, and our efficiency is increasing. The sensitivity needed for these measurements is up to 100 times better than Spitzer's design criteria, so careful treatment of systematic error is critically important and first-order approximations rarely work. The new pipeline

  16. Galactic structure

    International Nuclear Information System (INIS)

    1989-01-01

    The occurrence of hot, apparently normal, massive stars far from the galactic plane has been a major puzzle in an understanding of galactic structure and evolution. Such stars have been discovered and studied at the South African Astronomical Observatory (SAAO) over a number of years. During 1989 further evidence has been obtained indicating that these stars are normal, massive objects. Other studies of galactic structure conducted by the SAAO have included research on: the central bulge region of our galaxy; populations of M giants in the galaxy; a faint blue object survey; a survey of the galactic plane for distant Cepheid variables; interstellar reddening, and K-type dwarfs as tracers for the gravitational force perpendicular to the galactic plane. 1 fig

  17. Galactic dynamics

    CERN Document Server

    Binney, James

    2008-01-01

    Since it was first published in 1987, Galactic Dynamics has become the most widely used advanced textbook on the structure and dynamics of galaxies and one of the most cited references in astrophysics. Now, in this extensively revised and updated edition, James Binney and Scott Tremaine describe the dramatic recent advances in this subject, making Galactic Dynamics the most authoritative introduction to galactic astrophysics available to advanced undergraduate students, graduate students, and researchers. Every part of the book has been thoroughly overhauled, and many section

  18. SPITZER OBSERVATIONS OF YOUNG RED QUASARS

    International Nuclear Information System (INIS)

    Urrutia, Tanya; Lacy, Mark; Spoon, Henrik; Glikman, Eilat; Petric, Andreea; Schulz, Bernhard

    2012-01-01

    We present mid-infrared spectra and photometry of 13 redshift 0.4 < z < 1 dust reddened quasars obtained with Spitzer IRS and MIPS. We compare properties derived from their infrared spectral energy distributions (intrinsic active galactic nucleus (AGN) luminosity and far-infrared luminosity from star formation) to the host luminosities and morphologies from Hubble Space Telescope imaging, and black hole masses estimated from optical and/or near-infrared spectroscopy. Our results are broadly consistent with models in which most dust reddened quasars are an intermediate phase between a merger-driven starburst triggering a completely obscured AGN, and a normal, unreddened quasar. We find that many of our objects have high accretion rates, close to the Eddington limit. These objects tend to fall below the black hole mass-bulge luminosity relation as defined by local galaxies, whereas most of our low accretion rate objects are slightly above the local relation, as typical for normal quasars at these redshifts. Our observations are therefore most readily interpreted in a scenario in which galaxy stellar mass growth occurs first by about a factor of three in each merger/starburst event, followed sometime later by black hole growth by a similar amount. We do not, however, see any direct evidence for quasar feedback affecting star formation in our objects, for example, in the form of a relationship between accretion rate and star formation. Five of our objects, however, do show evidence for outflows in the [O III]5007 Å emission line profile, suggesting that the quasar activity is driving thermal winds in at least some members of our sample.

  19. Spitzer - Hot & Colorful Student Activities

    Science.gov (United States)

    McDonald, D.; Rebull, L. M.; DeWolf, C.; Guastella, P.; Johnson, C. H.; Schaefers, J.; Spuck, T.; McDonald, J. G., III; DeWolf, T.; Brock, S.; Boerma, J.; Bemis, G.; Paulsen, K.; Yueh, N.; Peter, A.; Wassmer, W.; Haber, R.; Scaramucci, A.; Butchart, J.; Holcomb, A.; Karns, B.; Kennedy, S.; Siegel, R.; Weiser, S.

    2009-01-01

    In this poster, we present the results of several activities developed for the general science student to explore infrared light. The first activity involved measuring infrared radiation using an updated version of Newton's experiment of splitting white light and finding IR radiation. The second used Leslie's cube to allow students to observe different radiators, while the third used a modern infrared thermometer to measure and identify IR sources in an enclosed box. The last activity involved students making false-color images from narrow-band filter images from data sets from Spitzer Space Telescope, STScI Digitized Sky Survey and other sources. Using computer programs like Adobe Photoshop and free software such as ds9, Spot and Leopard, poster-like images were created by the students. This research is funded by the Spitzer Science Center (SSC) and the National Optical Astronomy Observatory (NOAO). Please see our companion poster, Johnson et al., on the science aspect of this program, and another poster on the educational aspects, Guastella et al.

  20. Spitzer Science Center within an Enterprise Architecture

    Science.gov (United States)

    Handley, T.

    2007-10-01

    The Spitzer Science Center's (SSC) evolutionary development approach, coupled with a flexible, scaleable hardware and software architecture has been key in Spitzer's ability to handle an explosion of data products, evolving data definitions, and changing data quality requirements. Spitzer is generating (depending on the campaign and instrument) about 10 TB of pre-archive data every 14 to 20 days. This generally reduces to between 3 TB and 6 TB of standard products, again depending on the campaign and instrument. This paper will discuss (1) the Spitzer Science Center's responses to evolving data, quality, and processing requirements and (2) how robust or not was the original architecture to allow Spitzer to accommodate on-going change.

  1. Hunting Elusive SPRITEs with Spitzer

    Science.gov (United States)

    Kohler, Susanna

    2017-05-01

    In recent years, astronomers have developed many wide-field imaging surveys in which the same targets are observed again and again. This new form of observing has allowed us to discover optical and radio transients explosive or irregular events with durations ranging from seconds to years. The dynamic infrared sky, however, has remained largely unexplored until now.Infrared ExplorationExample of a transient: SPIRITS 14ajc was visible when imaged by SPIRITS in 2014 (left) but it wasnt there during previous imaging between 2004 and 2008 (right). The bottom frame shows the difference between the two images. [Adapted from Kasliwal et al. 2017]Why hunt for infrared transients? Optical wavelengths dont allow us to observe events that are obscured, such that their own structure or their surroundings hide them from our view. Both supernovae and luminous red novae (associated with stellar mergers) are discoverable as infrared transients, and there may well be new types of transients in infrared that we havent seen before!To explore this uncharted territory, a team of scientists developed SPIRITS, the Spitzer Infrared Intensive Transients Survey. Begun in 2014, SPIRITS is a five-year long survey that uses the Spitzer Space Telescope to conduct a systematic search for mid-infrared transients in nearby galaxies.In a recent publication led by Mansi Kasliwal (Caltech and the Carnegie Institution for Science), the SPIRITS team has now detailed how their survey works and what theyve discovered in its first year.The light curves of SPRITEs (red stars) lie in the mid-infared luminosity gap between novae (orange) and supernovae (blue). [Kasliwal et al. 2017]Mystery TransientsKasliwal and collaborators used Spitzer to monitor 190 nearby galaxies. In SPIRITS first year, they found over 1958 variable stars and 43 infrared transient sources. Of these 43 transients, 21 were known supernovae, 4 were in the luminosity range of novae, and 4 had optical counterparts. The remaining 14 events

  2. Galactic models

    International Nuclear Information System (INIS)

    Buchler, J.R.; Gottesman, S.T.; Hunter, J.H. Jr.

    1990-01-01

    Various papers on galactic models are presented. Individual topics addressed include: observations relating to galactic mass distributions; the structure of the Galaxy; mass distribution in spiral galaxies; rotation curves of spiral galaxies in clusters; grand design, multiple arm, and flocculent spiral galaxies; observations of barred spirals; ringed galaxies; elliptical galaxies; the modal approach to models of galaxies; self-consistent models of spiral galaxies; dynamical models of spiral galaxies; N-body models. Also discussed are: two-component models of galaxies; simulations of cloudy, gaseous galactic disks; numerical experiments on the stability of hot stellar systems; instabilities of slowly rotating galaxies; spiral structure as a recurrent instability; model gas flows in selected barred spiral galaxies; bar shapes and orbital stochasticity; three-dimensional models; polar ring galaxies; dynamical models of polar rings

  3. THE SPITZER -HETDEX EXPLORATORY LARGE-AREA SURVEY

    International Nuclear Information System (INIS)

    Papovich, C.; Shipley, H. V.; Mehrtens, N.; Lanham, C.; DePoy, D. L.; Kawinwanichakij, L.; Lacy, M.; Ciardullo, R.; Gronwall, C.; Finkelstein, S. L.; Drory, N.; Gebhardt, K.; Hill, G. J.; Jogee, S.; Bassett, R.; Behroozi, P.; Blanc, G. A.; Jong, R. S. de; Gawiser, E.; Hopp, U.

    2016-01-01

    We present post-cryogenic Spitzer imaging at 3.6 and 4.5 μ m with the Infrared Array Camera (IRAC) of the Spitzer /HETDEX Exploratory Large-Area (SHELA) survey. SHELA covers ≈24 deg 2 of the Sloan Digital Sky Survey “Stripe 82” region, and falls within the footprints of the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) and the Dark Energy Survey. The HETDEX blind R ∼ 800 spectroscopy will produce ∼200,000 redshifts from the Ly α emission for galaxies in the range 1.9 <  z  < 3.5, and an additional ∼200,000 redshifts from the [O ii] emission for galaxies at z  < 0.5. When combined with deep ugriz images from the Dark Energy Camera, K -band images from NEWFIRM, and other ancillary data, the IRAC photometry from Spitzer will enable a broad range of scientific studies of the relationship between structure formation, galaxy stellar mass, halo mass, the presence of active galactic nuclei, and environment over a co-moving volume of ∼0.5 Gpc 3 at 1.9 <  z  < 3.5. Here, we discuss the properties of the SHELA IRAC data set, including the data acquisition, reduction, validation, and source catalogs. Our tests show that the images and catalogs are 80% (50%) complete to limiting magnitudes of 22.0 (22.6) AB mag in the detection image, which is constructed from the weighted sum of the IRAC 3.6 and 4.5 μ m images. The catalogs reach limiting sensitivities of 1.1  μ Jy at both 3.6 and 4.5 μ m (1 σ , for R = 2″ circular apertures). As a demonstration of the science, we present IRAC number counts, examples of highly temporally variable sources, and galaxy surface density profiles of rich galaxy clusters. In the spirit of the Spitzer Exploratory programs, we provide all of the images and catalogs as part of the publication.

  4. THE TAURUS SPITZER SURVEY: NEW CANDIDATE TAURUS MEMBERS SELECTED USING SENSITIVE MID-INFRARED PHOTOMETRY

    International Nuclear Information System (INIS)

    Rebull, L. M.; Padgett, D. L.; McCabe, C.-E.; Noriega-Crespo, A.; Carey, S. J.; Brooke, T.; Hillenbrand, L. A.; Stapelfeldt, K. R.; Angione, J. R.; Huard, T.; Terebey, S.; Audard, M.; Baldovin-Saavedra, C.; Monin, J.-L.; Menard, F.; Bouvier, J.; Fukagawa, M.; Guedel, M.; Knapp, G. R.; Allen, L. E.

    2010-01-01

    We report on the properties of pre-main-sequence objects in the Taurus molecular clouds as observed in seven mid- and far-infrared bands with the Spitzer Space Telescope. There are 215 previously identified members of the Taurus star-forming region in our ∼44 deg 2 map; these members exhibit a range of Spitzer colors that we take to define young stars still surrounded by circumstellar dust (noting that ∼20% of the bona fide Taurus members exhibit no detectable dust excesses). We looked for new objects in the survey field with similar Spitzer properties, aided by extensive optical, X-ray, and ultraviolet imaging, and found 148 new candidate members of Taurus. We have obtained follow-up spectroscopy for about half the candidate sample, thus far confirming 34 new members, three probable new members, and 10 possible new members, an increase of 15%-20% in Taurus members. Of the objects for which we have spectroscopy, seven are now confirmed extragalactic objects, and one is a background Be star. The remaining 93 candidate objects await additional analysis and/or data to be confirmed or rejected as Taurus members. Most of the new members are Class II M stars and are located along the same cloud filaments as the previously identified Taurus members. Among non-members with Spitzer colors similar to young, dusty stars are evolved Be stars, planetary nebulae, carbon stars, galaxies, and active galactic nuclei.

  5. THE ORIGIN OF THE INFRARED EMISSION IN RADIO GALAXIES. II. ANALYSIS OF MID- TO FAR-INFRARED SPITZER OBSERVATIONS OF THE 2JY SAMPLE

    NARCIS (Netherlands)

    Dicken, D.; Tadhunter, C.; Axon, D.; Morganti, R.; Inskip, K. J.; Holt, J.; Delgado, R. Gonzalez; Groves, B.

    2009-01-01

    We present an analysis of deep mid- to far-infrared (MFIR) Spitzer photometric observations of the southern 2Jy sample of powerful radio sources (0.05 galactic nucleus (AGN), starburst activity and MFIR

  6. The Java Legacy Interface

    DEFF Research Database (Denmark)

    Korsholm, Stephan

    2007-01-01

    The Java Legacy Interface is designed to use Java for encapsulating native legacy code on small embedded platforms. We discuss why existing technologies for encapsulating legacy code (JNI) is not sufficient for an important range of small embedded platforms, and we show how the Java Legacy...... Interface offers this previously missing functionality. We describe an implementation of the Java Legacy Interface for a particular virtual machine, and how we have used this virtual machine to integrate Java with an existing, commercial, soft real-time, C/C++ legacy platform....

  7. Legacy Extragalactic UV Survey (LEGUS) With the Hubble Space Telescope. I. Survey Description

    NARCIS (Netherlands)

    Calzetti, D.; Lee, J.C.; Sabbi, E.; Adamo, A.; Smith, L.J.; Andrews, J.E.; Ubeda, L.; Bright, S.N.; Thilker, D.; Aloisi, A.; Brown, T.M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G.C.; da Silva, R.; de Mink, S.E.; Dobbs, C.; Elmegreen, B.G.; Elmegreen, D.M.; Evans, A.S.; Fumagalli, M.; Gallagher III, J.S.; Gouliermis, D.A.; Grebel, E.K.; Herrero, A.; Hunter, D.A.; Johnson, K.E.; Kennicutt, R.C.; Kim, H.; Krumholz, M.R.; Lennon, D.; Levay, K.; Martin, C.; Nair, P.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M.W.; Ryon, J.E.; Schaerer, D.; Schiminovich, D.; Tosi, M.; Van Dyk, S.D.; Walterbos, R.; Whitmore, B.C.; Wofford, A.

    2015-01-01

    The Legacy ExtraGalactic UV Survey (LEGUS) is a Cycle 21 Treasury program on the Hubble Space Telescope aimed at the investigation of star formation and its relation with galactic environment in nearby galaxies, from the scales of individual stars to those of ~kiloparsec-size clustered structures.

  8. Dynamics and evolution of galactic nuclei (princeton series in astrophysics)

    CERN Document Server

    Merritt, David

    2013-01-01

    Deep within galaxies like the Milky Way, astronomers have found a fascinating legacy of Einstein's general theory of relativity: supermassive black holes. Connected to the evolution of the galaxies that contain these black holes, galactic nuclei are the sites of uniquely energetic events, including quasars, stellar tidal disruptions, and the generation of gravitational waves. This textbook is the first comprehensive introduction to dynamical processes occurring in the vicinity of supermassive black holes in their galactic environment. Filling a critical gap, it is an authoritative resource for astrophysics and physics graduate students, and researchers focusing on galactic nuclei, the astrophysics of massive black holes, galactic dynamics, and gravitational wave detection. It is an ideal text for an advanced graduate-level course on galactic nuclei and as supplementary reading in graduate-level courses on high-energy astrophysics and galactic dynamics. David Merritt summarizes the theoretical work of the las...

  9. Spitzer 3.6 and 5.8 micron Monitoring of the Seyfert 1 NGC 4051

    Science.gov (United States)

    Gorjian, Varoujan; Adkins, J.; Borders, K.; Kelly, S.; Martin, C.; Mendez, B.; Paradis, J.; Perreira, V.; Pittman, P.; Sepulveda, B.; NGC 4051 Monitoring Group

    2009-01-01

    We used the Spitzer Space Telescope Infrared Array Camera (IRAC) to monitor the Seyfert 1 active galactic nucleus NGC 4051. We took data at 3.6 and 5.8 microns every day for 10 days in June 2008. We also observed in the optical at B, V, and R bands starting a month before the IRAC observations with various ground based observatories, though we were unable to achieve daily coverage. We will present the IR and optical light curves and will search for correlated variability that may be evidence of dust reverberation. For the education and public outreach component of this program please see Sepulveda et al.

  10. Spitzer identification of potentially active Near-Earth Asteroids

    Science.gov (United States)

    Mommert, Michael; Trilling, David; Hora, Joseph; Smith, Howard; Chesley, Steve; Emery, Josh; Farnocchia, Davide; Fazio, Giovanni; Harris, Alan; Mueller, Migo

    2017-04-01

    The separation between asteroids and comets has become less clear with the discovery of a small group of asteroids that display comet-like activity. While the activity is attributed to different mechanisms, some objects seem to activate close to the Sun. Near-Earth Asteroids (NEAs) come close to the Earth and the Sun, constituting a natural laboratory for the study of thermally induced activity. Two NEA sub-populations are especially suspected of being potentially active: dormant comets and near-Sun asteroids. We propose 12.4 hrs of Spitzer IRAC observations of 3 near-Sun asteroids and one dormant comet (3552) Don Quixote, about which we have already published. Our goals are (1) to search for activity in Don Quixote, which showed CO/CO2 activity during its previous apparition and (2) to search for activity and measure the diameters and albedos of the near-Sun asteroids. In combination with a funded ground-based observing program, our results will provide significant legacy value to the investigation of activity in near-Earth asteroids.

  11. Chemical abundances and dust in planetary nebulae in the Galactic bulge

    NARCIS (Netherlands)

    Gutenkunst, S.; Bernard-Salas, J.; Pottasch, S. R.; Sloan, G. C.; Houck, J. R.

    2008-01-01

    We present mid-infrared Spitzer spectra of 11 planetary nebulae in the Galactic bulge. We derive argon, neon, sulfur, and oxygen abundances for them using mainly infrared line fluxes combined with some optical line fluxes from the literature. Due to the high extinction toward the bulge, the infrared

  12. Lyman Spitzer: Life, Times, and Science

    Indian Academy of Sciences (India)

    Lyman Spitzer was one of the major figures of twentieth centurytheoretical astrophysics. Over more than fifty years,he kept up sustained research of his own, on problems concerningthe interstellar medium, star formation, and galaxies.In addition he was a major influence on observationalprogrammes, and created a thriving ...

  13. Lyman Spitzer: Life, Times, and Science

    Indian Academy of Sciences (India)

    College, Cambridge, in the academic year 1935–36. It was com- mon in those days for promising students from the United States to spend some time in England or Europe – the precise opposite of the situation today! Cambridge exposed Spitzer to the most distinguished astrophysi- cist of that time – Arthur Eddington.

  14. Galactic bulges

    CERN Document Server

    Peletier, Reynier; Gadotti, Dimitri

    2016-01-01

    This book consists of invited reviews on Galactic Bulges written by experts in the field. A central point of the book is that, while in the standard picture of galaxy formation a significant amount of the baryonic mass is expected to reside in classical bulges, the question what is the fraction of galaxies with no classical bulges in the local Universe has remained open. The most spectacular example of a galaxy with no significant classical bulge is the Milky Way. The reviews of this book attempt to clarify the role of the various types of bulges during the mass build-up of galaxies, based on morphology, kinematics, and stellar populations, and connecting their properties at low and high redshifts. The observed properties are compared with the predictions of the theoretical models, accounting for the many physical processes leading to the central mass concentration and their destruction in galaxies. This book serves as an entry point for PhD students and non-specialists and as a reference work for researchers...

  15. Planck, Herschel & Spitzer unveil overdense z>2 regions

    Science.gov (United States)

    Dole, Herve; Chary, Ranga-Ram; Chary, Ranga; Frye, Brenda; Martinache, Clement; Guery, David; Le Floc'h, Emeric; Altieri, Bruno; Flores-Cacho, Ines; Giard, Martin; Hurier, Guillaume; Lagache, Guilaine; Montier, Ludovic; Nesvadba, Nicole; Omont, Alain; Pointecouteau, Etienne; Pierini, Daniele; Puget, Jean-Loup; Scott, Douglas; Soucail, Genevieve

    2014-12-01

    At which cosmic epoch did massive galaxy clusters assemble their baryons? How does star formation occur in the most massive, most rapidly collapsing dark-matter-dense environments in the early Universe? To answer these questions, we take the completely novel approach to select the most extreme z>~2 star-forming overdensities seen over the entire sky. This selection nicely complements the other existing selections for high redshift clusters (i.e., by stellar mass, or by total mass like Sunyaev-Zeldovish (SZ) or X-ray selection). We make use of the Planck all-sky submillimetre survey to systematically identify the rarest, most luminous high-redshift sub-mm sources on the sky, either strongly gravitationally lensed galaxies, or the joint FIR/sub-mm emission from multiple intense starbursts. We observed 228 Planck sources with Herschel/SPIRE and discovered that most of them are overdensities of red galaxies with extremely high star formation rates (typically 7.e3 Msun/yr for a structure). Only Spitzer data can allow a better understanding of these promising Planck+Herschel selected sources, as is shown on a first set of IRAC data on 40 targets in GO9: (i) the good angular resolution and sensitivity of IRAC allows a proper determination of the clustered nature of each Herschel/SPIRE source; (ii) IRAC photometry (often associated with J, K) allows a good estimate of the colors and approximate photometric redshift. Note spectroscopic redshifts are available for two cluster candidates, at z=1.7 and z=2.3, confirming their high redshift nature. The successful GO9 observation of 40 fields showed that about half to be >7sigma overdensities of red IRAC sources. These observations were targeting the whole range of Herschel overdensities and significances. We need to go deeper into the Spitzer sample and acquire complete coverage of the most extreme Herschel overdensities (54 new fields). Such a unique sample has legacy value, and this is the last opportunity prior to JWST

  16. Spitzer secondary eclipses of Qatar-1b

    Science.gov (United States)

    Garhart, Emily; Deming, Drake; Mandell, Avi; Knutson, Heather; Fortney, Jonathan J.

    2018-02-01

    Aims: Previous secondary eclipse observations of the hot Jupiter Qatar-1b in the Ks band suggest that it may have an unusually high day side temperature, indicative of minimal heat redistribution. There have also been indications that the orbit may be slightly eccentric, possibly forced by another planet in the system. We investigate the day side temperature and orbital eccentricity using secondary eclipse observations with Spitzer. Methods: We observed the secondary eclipse with Spitzer/IRAC in subarray mode, in both 3.6 and 4.5 μm wavelengths. We used pixel-level decorrelation to correct for Spitzer's intra-pixel sensitivity variations and thereby obtain accurate eclipse depths and central phases. Results: Our 3.6 μm eclipse depth is 0.149 ± 0.051% and the 4.5 μm depth is 0.273 ± 0.049%. Fitting a blackbody planet to our data and two recent Ks band eclipse depths indicates a brightness temperature of 1506 ± 71 K. Comparison to model atmospheres for the planet indicates that its degree of longitudinal heat redistribution is intermediate between fully uniform and day-side only. The day side temperature of the planet is unlikely to be as high (1885 K) as indicated by the ground-based eclipses in the Ks band, unless the planet's emergent spectrum deviates strongly from model atmosphere predictions. The average central phase for our Spitzer eclipses is 0.4984 ± 0.0017, yielding e cos ω = -0.0028 ± 0.0027. Our results are consistent with a circular orbit, and we constrain e cos ω much more strongly than has been possible with previous observations. Tables of the lightcurve data are 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/610/A55

  17. Efficient Mosaicking of Spitzer Space Telescope Images

    Science.gov (United States)

    Jacob, Joseph; Makovoz, David; Eisenhardt, Peter

    2007-01-01

    A parallel version of the MOPEX software, which generates mosaics of infrared astronomical images acquired by the Spitzer Space Telescope, extends the capabilities of the prior serial version. In the parallel version, both the input image space and the output mosaic space are divided among the available parallel processors. This is the only software that performs the point-source detection and the rejection of spurious imaging effects of cosmic rays required by Spitzer scientists. This software includes components that implement outlier-detection algorithms that can be fine-tuned for a particular set of image data by use of a number of adjustable parameters. This software has been used to construct a mosaic of the Spitzer Infrared Array Camera Shallow Survey, which comprises more than 17,000 exposures in four wavelength bands from 3.6 to 8 m and spans a solid angle of about 9 square degrees. When this software was executed on 32 nodes of the 1,024-processor Cosmos cluster computer at NASA s Jet Propulsion Laboratory, a speedup of 8.3 was achieved over the serial version of MOPEX. The performance is expected to improve dramatically once a true parallel file system is installed on Cosmos.

  18. VizieR Online Data Catalog: Spitzer observations of Taurus members (Luhman+, 2010)

    Science.gov (United States)

    Luhman, K. L.; Allen, P. R.; Espaillat, C.; Hartmann, L.; Calvet, N.

    2016-03-01

    For our census of the disk population in Taurus, we use images at 3.6, 4.5, 5.8, and 8.0um obtained with Spitzer's Infrared Array Camera (IRAC) and images at 24um obtained with the Multiband Imaging Photometer for Spitzer (MIPS). The cameras produced images with FWHM=1.6"-1.9" from 3.6 to 8.0um and FWHM=5.9" at 24um. The available data were obtained through Guaranteed Time Observations for PID = 6, 36, 37 (G. Fazio), 53 (G. Rieke), 94 (C. Lawrence), 30540 (G. Fazio, J. Houck), and 40302 (J. Houck), Director's Discretionary Time for PID = 462 (L. Rebull), Legacy programs for PID = 139, 173 (N. Evans), and 30816 (D. Padgett), and General Observer programs for PID = 3584 (D. Padgett), 20302 (P. Andre), 20386 (P. Myers), 20762 (J. Swift), 30384 (T. Bourke), 40844 (C. McCabe), and 50584 (D. Padgett). The IRAC and MIPS observations were performed through 180 and 137 Astronomical Observation Requests (AORs), respectively. The characteristics of the resulting images are summarized in Tables 1 and 2. (6 data files).

  19. Galactic radio astronomy

    CERN Document Server

    Sofue, Yoshiaki

    2017-01-01

    This book is a concise primer on galactic radio astronomy for undergraduate and graduate students, and provides wide coverage of galactic astronomy and astrophysics such as the physics of interstellar matter and the dynamics and structure of the Milky Way Galaxy and galaxies. Radio astronomy and its technological development have led to significant progress in galactic astronomy and contributed to understanding interstellar matter and galactic structures. The book begins with the fundamental physics of radio-wave radiation, i.e., black body radiation, thermal emission, synchrotron radiation, and HI and molecular line emissions. The author then gives overviews of ingredients of galactic physics, including interstellar matter such as the neutral (HI), molecular hydrogen, and ionized gases, as well as magnetic fields in galaxies. In addition, more advanced topics relevant to the Galaxy and galaxies are also contained here: star formation, supernova remnants, the Galactic Center and black holes, galactic dynamics...

  20. SPIRITS: Uncovering Unusual Infrared Transients with Spitzer

    Energy Technology Data Exchange (ETDEWEB)

    Kasliwal, Mansi M.; Jencson, Jacob E.; Tinyanont, Samaporn; Cao, Yi; Cook, David [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Bally, John [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Masci, Frank; Armus, Lee [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Cody, Ann Marie [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Bond, Howard E. [Dept. of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Contreras, Carlos [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Dykhoff, Devin A.; Amodeo, Samuel; Carlon, Robert L.; Cass, Alexander C.; Corgan, David T.; Faella, Joseph [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S. E., University of Minnesota, Minneapolis, MN 55455 (United States); Boyer, Martha [NASA Goddard Space Flight Center, MC 665, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Cantiello, Matteo [Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, NY 10010 (United States); Fox, Ori D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2017-04-20

    We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS—SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer /IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. We discovered over 1958 variables and 43 transients. Here, we describe the survey design and highlight 14 unusual infrared transients with no optical counterparts to deep limits, which we refer to as SPRITEs (eSPecially Red Intermediate-luminosity Transient Events). SPRITEs are in the infrared luminosity gap between novae and supernovae, with [4.5] absolute magnitudes between −11 and −14 (Vega-mag) and [3.6]–[4.5] colors between 0.3 mag and 1.6 mag. The photometric evolution of SPRITEs is diverse, ranging from <0.1 mag yr{sup −1} to >7 mag yr{sup −1}. SPRITEs occur in star-forming galaxies. We present an in-depth study of one of them, SPIRITS 14ajc in Messier 83, which shows shock-excited molecular hydrogen emission. This shock may have been triggered by the dynamic decay of a non-hierarchical system of massive stars that led to either the formation of a binary or a protostellar merger.

  1. SPITZER SECONDARY ECLIPSES OF WASP-18b

    International Nuclear Information System (INIS)

    Nymeyer, Sarah; Harrington, Joseph; Hardy, Ryan A.; Stevenson, Kevin B.; Campo, Christopher J.; Blecic, Jasmina; Bowman, William C.; Britt, Christopher B. T.; Cubillos, Patricio; Madhusudhan, Nikku; Collier-Cameron, Andrew; Maxted, Pierre F. L.; Loredo, Thomas J.; Hellier, Coel; Anderson, David R.; Gillon, Michael; Hebb, Leslie; Wheatley, Peter J.; Pollacco, Don

    2011-01-01

    The transiting exoplanet WASP-18b was discovered in 2008 by the Wide Angle Search for Planets project. The Spitzer Exoplanet Target of Opportunity Program observed secondary eclipses of WASP-18b using Spitzer's Infrared Array Camera in the 3.6 μm and 5.8 μm bands on 2008 December 20, and in the 4.5 μm and 8.0 μm bands on 2008 December 24. We report eclipse depths of 0.30% ± 0.02%, 0.39% ± 0.02%, 0.37% ± 0.03%, 0.41% ± 0.02%, and brightness temperatures of 3100 ± 90, 3310 ± 130, 3080 ± 140, and 3120 ± 110 K in order of increasing wavelength. WASP-18b is one of the hottest planets yet discovered—as hot as an M-class star. The planet's pressure-temperature profile most likely features a thermal inversion. The observations also require WASP-18b to have near-zero albedo and almost no redistribution of energy from the day side to the night side of the planet.

  2. SPITZER MICROLENS MEASUREMENT OF A MASSIVE REMNANT IN A WELL-SEPARATED BINARY

    Energy Technology Data Exchange (ETDEWEB)

    Shvartzvald, Y.; Bryden, G.; Henderson, C. B. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Gould, A.; Fausnaugh, M.; Gaudi, B. S.; Pogge, R. W.; Wibking, B.; Zhu, W. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Han, C. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Bozza, V.; Novati, S. Calchi [Dipartimento di Fisica “E. R. Caianiello,” Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano (Italy); Friedmann, M. [School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Hundertmark, M. [Niels Bohr Institute and Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen K (Denmark); Beichman, C. [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Carey, S. [Spitzer, Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Kerr, T.; Varricatt, W. [UKIRT, 660 N. Aohoku Place, University Park, Hilo, HI 96720 (United States); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Collaboration: and; Spitzer team; OGLE group; KMTNet group; Wise group; RoboNet; MiNDSTEp; and others

    2015-12-01

    We report the detection and mass measurement of a binary lens OGLE-2015-BLG-1285La,b, with the more massive component having M{sub 1} > 1.35 M{sub ⊙} (80% probability). A main-sequence star in this mass range is ruled out by limits on blue light, meaning that a primary in this mass range must be a neutron star (NS) or black hole (BH). The system has a projected separation r{sub ⊥} = 6.1 ± 0.4 AU and lies in the Galactic bulge. These measurements are based on the “microlens parallax” effect, i.e., comparing the microlensing light curve as seen from Spitzer, which lay at 1.25 AU projected from Earth, to the light curves from four ground-based surveys, three in the optical and one in the near-infrared. Future adaptive optics imaging of the companion by 30 m class telescopes will yield a much more accurate measurement of the primary mass. This discovery both opens the path and defines the challenges to detecting and characterizing BHs and NSs in wide binaries, with either dark or luminous companions. In particular, we discuss lessons that can be applied to future Spitzer and Kepler K2 microlensing parallax observations.

  3. Galactic Bulge Giants: Probing Stellar and Galactic Evolution. 1. Catalogue of Spitzer IRAC and MIPS Sources (PREPRINT)

    Science.gov (United States)

    2010-12-29

    Athens, Greece 4 Dipartimento di Fisica Generale ”A. Avogadro ”, Universita degli Studi di Torino, Via Pietro Giuria 1, 10125 Torino, Italy 5...and the data quality. ar X iv :1 00 2. 50 15 v1 [ as tr o- ph . S R ] 2 6 Fe b 20 10 Report Documentation Page Form ApprovedOMB No. 0704-0188...should be aware that notwithstanding any other provision of law , no person shall be subject to a penalty for failing to comply with a collection of

  4. Serendipity Observations of Far Infrared Cirrus Emission in the Spitzer Infrared Nearby Galaxies Survey: Analysis of Far-Infrared Correlations

    Science.gov (United States)

    Bot, Caroline; Helou, George; Boulanger, François; Lagache, Guilaine; Miville-Deschenes, Marc-Antoine; Draine, Bruce; Martin, Peter

    2009-04-01

    We present an analysis of far-infrared (FIR) dust emission from diffuse cirrus clouds. This study is based on serendipitous observations at 160 μm at high-galactic latitude with the Multiband Imaging Photometer onboard the Spitzer Space Telescope by the Spitzer Infrared Nearby Galaxies Survey. These observations are complemented with IRIS data at 100 and 60 μm and constitute one of the most sensitive and unbiased samples of FIR observations at a small scale of diffuse interstellar clouds. Outside regions dominated by the cosmic infrared background fluctuations, we observe a substantial scatter in the 160/100 colors from cirrus emission. We compared the 160/100 color variations to 60/100 colors in the same fields and find a trend of decreasing 60/100 with increasing 160/100. This trend cannot be accounted for by current dust models by changing solely the interstellar radiation field. It requires a significant change of dust properties such as grain size distribution or emissivity or a mixing of clouds in different physical conditions along the line of sight. These variations are important as a potential confusing foreground for extragalactic studies. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.

  5. CANDELS : THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY

    NARCIS (Netherlands)

    Grogin, Norman A.; Kocevski, Dale D.; Faber, S. M.; Ferguson, Henry C.; Koekemoer, Anton M.; Riess, Adam G.; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Casertano, Stefano; Cassata, Paolo; Castellano, Marco; Challis, Peter; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J.; Cooray, Asantha Roshan; Croton, Darren J.; Daddi, Emanuele; Dahlen, Tomas; Dave, Romeel; de Mello, Duilia F.; Dekel, Avishai; Dickinson, Mark; Dolch, Timothy; Donley, Jennifer L.; Dunlop, James S.; Dutton, Aaron A.; Elbaz, David; Fazio, Giovanni G.; Filippenko, Alexei V.; Finkelstein, Steven L.; Fontana, Adriano; Gardner, Jonathan P.; Garnavich, Peter M.; Gawiser, Eric; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P.; Haeussler, Boris; Hopkins, Philip F.; Huang, Jia-Sheng; Huang, Kuang-Han; Jha, Saurabh W.; Kartaltepe, Jeyhan S.; Kirshner, Robert P.; Koo, David C.; Lai, Kamson; Lee, Kyoung-Soo; Li, Weidong; Lotz, Jennifer M.; Lucas, Ray A.; Madau, Piero; McCarthy, Patrick J.; McGrath, Elizabeth J.; McIntosh, Daniel H.; McLure, Ross J.; Mobasher, Bahram; Moustakas, Leonidas A.; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A.; Niemi, Sami-Matias; Noeske, Kai G.; Papovich, Casey J.; Pentericci, Laura; Pope, Alexandra; Primack, Joel R.; Rajan, Abhijith; Ravindranath, Swara; Reddy, Naveen A.; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R.; Rodney, Steven A.; Rosario, David J.; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Somerville, Rachel S.; Spinrad, Hyron; Straughn, Amber N.; Strolger, Louis-Gregory; Telford, Olivia; Teplitz, Harry I.; Trump, Jonathan R.; van der Wel, Arjen; Villforth, Carolin; Wechsler, Risa H.; Weiner, Benjamin J.; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yan, Hao-Jing; Yun, Min S.

    2011-01-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8-1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the

  6. Understanding legacy liabilities

    Energy Technology Data Exchange (ETDEWEB)

    Ossi, G.J. [Venable, LLP (United States)

    2005-08-01

    Among the most immediate issues facing operations with a workforce represented by the United Mine Workers of America (UMWA) are the so-called 'legacy liabilities'. Legacy liabilities fall under two categories: retiree health care and pension. The retiree health benefit obligations fall into two categories; statutory - those created under the Coal Industry Retiree Health Benefit Act of 1992 and contractual - the 1993 Employer Benefit Plan and the Individual Employer Plans. The pension liabilities are more straightforward; there are three different retirement plans in the NBCWA; the UMWA 1950 Pension Plan, the UMWA 1974 Pension Plan and the UMWA Cash Deferred Savings Plan of 1988.

  7. Altmetrics, Legacy Scholarship, and Scholarly Legacy

    Directory of Open Access Journals (Sweden)

    Lauren B. Collister

    2017-10-01

    Full Text Available When using alternative metrics (altmetrics to investigate the impact of a scholar’s work, researchers and librarians are typically cautioned that altmetrics will be less useful for older works of scholarship. This is because it is difficult to collect social media and other attention retroactively, and the numbers will be lower if the work was published before social media marketing and promotion were widely accepted in a field. In this article, we argue that altmetrics can provide useful information about older works in the form of documenting renewed attention to past scholarship as part of a scholar’s legacy. Using the altmetrics profile of the late Dr. Thomas E. Starzl, often referred to as “the father of modern transplantation”, we describe two cases where altmetrics provided information about renewed interest in his works: a controversy about race and genetics that shows the ongoing impact of a particular work, and posthumous remembrances by colleagues which reveal his scholarly legacy.

  8. Creating legacy through evaluation

    DEFF Research Database (Denmark)

    Degn, Hans-Peter; Lynghøj, Hanne; Hansen, Louise Ejgod

    is how to stimulate cultural legacy in certain directions through the emphasis of specific values in the strategic objectives and evaluation criteria. Another perspective is how, to whom and for what purpose evaluation results are reported and implemented, and thus how evaluation may affect design, aims...

  9. Analysis of Spitzer-IRS spectra of hyperluminous infrared galaxies

    Science.gov (United States)

    Ruiz, A.; Risaliti, G.; Nardini, E.; Panessa, F.; Carrera, F. J.

    2013-01-01

    Context. Hyperluminous infrared galaxies (HLIRG) are the most luminous persistent objects in the Universe. They exhibit extremely high star formation rates, and most of them seem to harbour an active galactic nucleus (AGN). They are unique laboratories for investigating the most extreme star formation and its connection to super-massive black hole growth. Aims: The relative AGN and starburst (SB) contributions to the total output in these objects is still debated. Our aim is to disentangle the AGN and SB emission of a sample of thirteen HLIRG. Methods: We studied the MIR low-resolution spectra of a sample of thirteen HLIRG obtained with the Infrared Spectrograph on board Spitzer. The 5-8 μm range is an optimal window for detecting AGN activity even in a heavily obscured environment. We performed an SB/AGN decomposition of the continuum using templates, which has been successfully applied for ULIRG in previous works. Results: The MIR spectra of all sources is largely dominated by AGN emission. By converting the 6 μm luminosity into IR luminosity, we found that ~80% of the sample shows an IR output dominated by the AGN emission. However, the SB activity is significant in all sources (mean SB contribution ~30%), showing star formation rates ~300-3000 M⊙ yr-1. With X-ray and MIR data we estimated the dust covering factor (CF) of these HLIRG, finding that a significant fraction presents a CF consistent with unity. Along with the high X-ray absorption shown by these sources, this suggests that large amounts of dust and gas enshroud the nucleus of these HLIRG, as also observed in ULIRG. Conclusions: Our results agree with previous studies of the IR SED of HLIRG using radiative transfer models, and we find strong evidence that all HLIRG harbour an AGN. Moreover, this work provides further support for the idea that AGN and SB are both crucial to understanding the properties of HLIRG. Our study of the CF supports the hypothesis that HLIRG can be divided into two

  10. Spitzer IRS Observations of FU Orionis Objects

    Science.gov (United States)

    Green, J. D.; Hartmann, L.; Calvet, N.; Watson, D. M.; Ibrahimov, M.; Furlan, E.; Sargent, B.; Forrest, W. J.

    2006-09-01

    We present 5-35 μm spectra, taken with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope, of five FU Orionis objects: FU Ori, V1515 Cyg, V1057 Cyg, BBW 76, and V346 Nor. All but V346 Nor reveal amorphous silicate grains in emission at 10 and 20 μm, and show water-vapor absorption bands at 5.8 and 6.8 μm and SiO or possibly methane absorption at 8 μm. These absorption features closely match these bands in model stellar photospheres-signs of the gaseous photospheres of the inner regions of these objects' accretion disks. The continuum emission at 5-8 μm is also consistent with such disks, and, for FU Orionis and BBW 76, longer wavelength emission may be fit by a model that includes moderate disk flaring. V1057 Cyg and V1515 Cyg have much more emission at longer wavelengths than the others, perhaps evidence of a substantial remnant of their natal, infalling envelopes.

  11. SHARC-II Mapping of Spitzer c2d Small Clouds and Cores

    Science.gov (United States)

    Wu, Jingwen; Dunham, Michael M.; Evans, Neal J., II; Bourke, Tyler L.; Young, Chadwick H.

    2007-04-01

    We present the results of a submillimeter survey of 53 low-mass dense cores with the Submillimeter High Angular Resolution Camera II (SHARC-II). The survey is a follow-up project to the Spitzer Legacy Program "From Molecular Cores to Planet-Forming Disks," with the purpose of creating a complete data set of nearby low-mass dense cores from the infrared to the millimeter. We present maps of 52 cores at 350 μm and three cores at 450 μm, two of which were observed at both wavelengths. Of these 52 cores, 41 were detected by SHARC-II; 32 contained one submillimeter source, while 9 contained multiple sources. For each submillimeter source detected, we report various source properties including source position, fluxes in various apertures, size, aspect ratio, and position angle. For the 12 cores that were not detected we present upper limits. The sources detected by SHARC-II have, on average, smaller sizes at the 2 σ contours than those derived from longer wavelength bolometer observations. We conclude that this is not caused by a failure to integrate long enough to detect the full extent of the core; instead it arises primarily from the fact that the observations presented in this survey are insensitive to smoothly varying extended emission. We find that SHARC-II observations of low-mass cores are much better suited to distinguishing between starless and protostellar cores than observations at longer wavelengths. Very low luminosity objects, a new class of objects being discovered by the Spitzer Space Telescope in cores previously classified as starless, look very similar at 350 μm to other cores with more luminous protostars.

  12. THE SPITZER INFRARED SPECTROGRAPH DEBRIS DISK CATALOG. I. CONTINUUM ANALYSIS OF UNRESOLVED TARGETS

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Christine H. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Mittal, Tushar [Department of Earth and Planetary Science, University of California Berkeley, Berkeley, CA 94720-4767 (United States); Kuchner, Marc [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Code 667, Greenbelt, MD 20771 (United States); Forrest, William J.; Watson, Dan M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Lisse, Carey M. [Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Manoj, P. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India); Sargent, Benjamin A., E-mail: cchen@stsci.edu [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2014-04-01

    During the Spitzer Space Telescope cryogenic mission, Guaranteed Time Observers, Legacy Teams, and General Observers obtained Infrared Spectrograph (IRS) observations of hundreds of debris disk candidates. We calibrated the spectra of 571 candidates, including 64 new IRAS and Multiband Imaging Photometer for Spitzer (MIPS) debris disks candidates, modeled their stellar photospheres, and produced a catalog of excess spectra for unresolved debris disks. For 499 targets with IRS excess but without strong spectral features (and a subset of 420 targets with additional MIPS 70 μm observations), we modeled the IRS (and MIPS data) assuming that the dust thermal emission was well-described using either a one- or two-temperature blackbody model. We calculated the probability for each model and computed the average probability to select among models. We found that the spectral energy distributions for the majority of objects (∼66%) were better described using a two-temperature model with warm (T {sub gr} ∼ 100-500 K) and cold (T {sub gr} ∼ 50-150 K) dust populations analogous to zodiacal and Kuiper Belt dust, suggesting that planetary systems are common in debris disks and zodiacal dust is common around host stars with ages up to ∼1 Gyr. We found that younger stars generally have disks with larger fractional infrared luminosities and higher grain temperatures and that higher-mass stars have disks with higher grain temperatures. We show that the increasing distance of dust around debris disks is inconsistent with self-stirred disk models, expected if these systems possess planets at 30-150 AU. Finally, we illustrate how observations of debris disks may be used to constrain the radial dependence of material in the minimum mass solar nebula.

  13. COLORS OF ELLIPTICALS FROM GALEX TO SPITZER

    International Nuclear Information System (INIS)

    Schombert, James M.

    2016-01-01

    Multi-color photometry is presented for a large sample of local ellipticals selected by morphology and isolation. The sample uses data from the Galaxy Evolution Explorer ( GALEX ), Sloan Digital Sky Survey (SDSS), Two Micron All-Sky Survey (2MASS), and Spitzer to cover the filters NUV , ugri , JHK and 3.6 μ m. Various two-color diagrams, using the half-light aperture defined in the 2MASS J filter, are very coherent from color to color, meaning that galaxies defined to be red in one color are always red in other colors. Comparison to globular cluster colors demonstrates that ellipticals are not composed of a single age, single metallicity (e.g., [Fe/H]) stellar population, but require a multi-metallicity model using a chemical enrichment scenario. Such a model is sufficient to explain two-color diagrams and the color–magnitude relations for all colors using only metallicity as a variable on a solely 12 Gyr stellar population with no evidence of stars younger than 10 Gyr. The [Fe/H] values that match galaxy colors range from −0.5 to +0.4, much higher (and older) than population characteristics deduced from Lick/IDS line-strength system studies, indicating an inconsistency between galaxy colors and line indices values for reasons unknown. The NUV colors have unusual behavior, signaling the rise and fall of the UV upturn with elliptical luminosity. Models with blue horizontal branch tracks can reproduce this behavior, indicating the UV upturn is strictly a metallicity effect.

  14. COLORS OF ELLIPTICALS FROM GALEX TO SPITZER

    Energy Technology Data Exchange (ETDEWEB)

    Schombert, James M., E-mail: jschombe@uoregon.edu [Department of Physics, University of Oregon, Eugene, OR 97403 (United States)

    2016-12-01

    Multi-color photometry is presented for a large sample of local ellipticals selected by morphology and isolation. The sample uses data from the Galaxy Evolution Explorer ( GALEX ), Sloan Digital Sky Survey (SDSS), Two Micron All-Sky Survey (2MASS), and Spitzer to cover the filters NUV , ugri , JHK and 3.6 μ m. Various two-color diagrams, using the half-light aperture defined in the 2MASS J filter, are very coherent from color to color, meaning that galaxies defined to be red in one color are always red in other colors. Comparison to globular cluster colors demonstrates that ellipticals are not composed of a single age, single metallicity (e.g., [Fe/H]) stellar population, but require a multi-metallicity model using a chemical enrichment scenario. Such a model is sufficient to explain two-color diagrams and the color–magnitude relations for all colors using only metallicity as a variable on a solely 12 Gyr stellar population with no evidence of stars younger than 10 Gyr. The [Fe/H] values that match galaxy colors range from −0.5 to +0.4, much higher (and older) than population characteristics deduced from Lick/IDS line-strength system studies, indicating an inconsistency between galaxy colors and line indices values for reasons unknown. The NUV colors have unusual behavior, signaling the rise and fall of the UV upturn with elliptical luminosity. Models with blue horizontal branch tracks can reproduce this behavior, indicating the UV upturn is strictly a metallicity effect.

  15. Polycyclic Aromatic Hydrocarbon Emission Toward the Galactic Bulge

    Science.gov (United States)

    Shannon, M. J.; Peeters, E.; Cami, J.; Blommaert, J. A. D. L.

    2018-03-01

    We examine polycyclic aromatic hydrocarbon (PAH), dust, and atomic/molecular emission toward the Galactic bulge using Spitzer Space Telescope observations of four fields: C32, C35, OGLE, and NGC 6522. These fields are approximately centered on (l, b) = (0.°0, 1.°0), (0.°0, ‑1.°0), (0.°4, ‑2.°4), and (1.°0, ‑3.°8), respectively. Far-infrared photometric observations complement the Spitzer/IRS spectroscopic data and are used to construct spectral energy distributions. We find that the dust and PAH emission are exceptionally similar between C32 and C35 overall, in part explained due to their locations—they reside on or near boundaries of a 7 Myr old Galactic outflow event and are partly shock-heated. Within the C32 and C35 fields, we identify a region of elevated Hα emission that is coincident with elevated fine-structure and [O IV] line emission and weak PAH feature strengths. We are likely tracing a transition zone of the outflow into the nascent environment. PAH abundances in these fields are slightly depressed relative to typical ISM values. In the OGLE and NGC 6522 fields, we observe weak features on a continuum dominated by zodiacal dust. SED fitting indicates that thermal dust grains in C32 and C35 have temperatures comparable to those of diffuse, high-latitude cirrus clouds. Little variability is detected in the PAH properties between C32 and C35, indicating that a stable population of PAHs dominates the overall spectral appearance. In fact, their PAH features are exceptionally similar to that of the M82 superwind, emphasizing that we are probing a local Galactic wind environment.

  16. A MID-INFRARED IMAGING SURVEY OF SUBMILLIMETER-SELECTED GALAXIES WITH THE SPITZER SPACE TELESCOPE

    International Nuclear Information System (INIS)

    Hainline, Laura J.; Blain, A. W.; Smail, Ian; Frayer, D. T.; Chapman, S. C.; Ivison, R. J.; Alexander, D. M.

    2009-01-01

    We present Spitzer-IRAC and MIPS mid-IR observations of a sample of 73 radio-detected submillimeter-selected galaxies (SMGs) with spectroscopic redshifts, the largest such sample published to date. From our data, we find that IRAC colors of SMGs are much more uniform as compared with rest-frame UV and optical colors, and z>1.5 SMGs tend to be redder in their mid-IR colors than both field galaxies and lower-z SMGs. However, the IRAC colors of the SMGs overlap those of field galaxies sufficiently that color-magnitude and color-color selection criteria suggested in the literature to identify SMG counterparts produce ambiguous counterparts within an 8'' radius in 20%-35% of cases. We use a rest-frame J-H versus H-K color-color diagram and a S 24 /S 8.0 versus S 8.0 /S 4.5 color-color diagram to determine that 13%-19% of our sample are likely to contain active galactic nuclei which dominate their mid-IR emission. We observe in the rest-frame JHK colors of our sample that the rest-frame near-IR emission of SMGs does not resemble that of the compact nuclear starburst observed in local ultraluminous IR galaxies and is consistent with more widely distributed star formation. We take advantage of the fact that many high-z galaxy populations selected at different wavelengths are detected by Spitzer to carry out a brief comparison of mid-IR properties of SMGs to UV-selected high-z galaxies, 24 μm-selected galaxies, and high-z radio galaxies, and find that SMGs have mid-IR fluxes and colors which are consistent with being more massive and more reddened than UV-selected galaxies, while the IRAC colors of SMGs are most similar to powerful high-z radio galaxies.

  17. SPATIAL VARIATIONS OF PAH PROPERTIES IN M17SW REVEALED BY SPITZER /IRS SPECTRAL MAPPING

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, M. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Chuo-ku, Sagamihara 252-5210 (Japan); Kaneda, H.; Ishihara, D.; Oyabu, S.; Suzuki, T.; Nishimura, A.; Kohno, M. [Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Onaka, T.; Ohashi, S. [Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nagayama, T.; Matsuo, M. [Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan); Umemoto, T.; Minamidani, T.; Fujita, S. [Nobeyama Radio Observatory, National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS), 462-2, Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Tsuda, Y., E-mail: yamagish@ir.isas.jaxa.jp [Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-0042 (Japan)

    2016-12-20

    We present Spitzer /IRS mid-infrared spectral maps of the Galactic star-forming region M17 as well as IRSF/SIRIUS Br γ and Nobeyama 45 m/FOREST {sup 13}CO ( J = 1–0) maps. The spectra show prominent features due to polycyclic aromatic hydrocarbons (PAHs) at wavelengths of 6.2, 7.7, 8.6, 11.3, 12.0, 12.7, 13.5, and 14.2  μ m. We find that the PAH emission features are bright in the region between the H ii region traced by Br γ and the molecular cloud traced by {sup 13}CO, supporting that the PAH emission originates mostly from photo-dissociation regions. Based on the spatially resolved Spitzer /IRS maps, we examine spatial variations of the PAH properties in detail. As a result, we find that the interband ratio of PAH 7.7  μ m/PAH 11.3  μ m varies locally near M17SW, but rather independently of the distance from the OB stars in M17, suggesting that the degree of PAH ionization is mainly controlled by local conditions rather than the global UV environments determined by the OB stars in M17. We also find that the interband ratios of the PAH 12.0  μ m, 12.7  μ m, 13.5  μ m, and 14.2  μ m features to the PAH 11.3  μ m feature are high near the M17 center, which suggests structural changes of PAHs through processing due to intense UV radiation, producing abundant edgy irregular PAHs near the M17 center.

  18. Simulated Galactic methanol maser distribution to constrain Milky Way parameters

    Science.gov (United States)

    Quiroga-Nuñez, L. H.; van Langevelde, H. J.; Reid, M. J.; Green, J. A.

    2017-08-01

    Context. Using trigonometric parallaxes and proper motions of masers associated with massive young stars, the Bar and Spiral Structure Legacy (BeSSeL) survey has reported the most accurate values of the Galactic parameters so far. The determination of these parameters with high accuracy has a widespread impact on Galactic and extragalactic measurements. Aims: This research is aimed at establishing the confidence with which such parameters can be determined. This is relevant for the data published in the context of the BeSSeL survey collaboration, but also for future observations, in particular from the southern hemisphere. In addition, some astrophysical properties of the masers can be constrained, notably the luminosity function. Methods: We have simulated the population of maser-bearing young stars associated with Galactic spiral structure, generating several samples and comparing them with the observed samples used in the BeSSeL survey. Consequently, we checked the determination of Galactic parameters for observational biases introduced by the sample selection. Results: Galactic parameters obtained by the BeSSeL survey do not seem to be biased by the sample selection used. In fact, the published error estimates appear to be conservative for most of the parameters. We show that future BeSSeL data and future observations with southern arrays will improve the Galactic parameters estimates and smoothly reduce their mutual correlation. Moreover, by modeling future parallax data with larger distance values and, thus, greater relative uncertainties for a larger numbers of sources, we found that parallax-distance biasing is an important issue. Hence, using fractional parallax uncertainty in the weighting of the motion data is imperative. Finally, the luminosity function for 6.7 GHz methanol masers was determined, allowing us to estimate the number of Galactic methanol masers.

  19. Investigating Space Weather Events Impacting the Spitzer Space Telescope

    Science.gov (United States)

    Cheng, Leo Y.; Hunt, Joseph C. Jr.; Stowers, Kennis; Lowrance, Patrick; Stewart, Andrzej; Travis, Paul

    2014-01-01

    Our understanding of the dynamical process in the space environment has increased dramatically. A relatively new field of study called "Space Weather" has emerged in the last few decades. Fundamental to the study of space weather is an understanding of how space weather events such as solar flares and coronal mass ejections impact spacecraft in varying orbits and distances around the Sun. Specialized space weather satellite monitoring systems operated by the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) allow scientists to predict space weather events affecting critical systems on and orbiting the Earth. However, the Spitzer Space Telescope is in an orbit far outside the areas covered by those space weather monitoring systems. This poses a challenge for the Spitzer's Mission Operations Team in determining whether space weather events affect Spitzer.

  20. SPITZER IRAC PHOTOMETRY FOR TIME SERIES IN CROWDED FIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Novati, S. Calchi; Beichman, C. [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Gould, A.; Fausnaugh, M.; Gaudi, B. S.; Pogge, R. W.; Wibking, B.; Zhu, W.; Poleski, R. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Bryden, G.; Henderson, C. B.; Shvartzvald, Y. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Carey, S. [Spitzer, Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Udalski, A.; Pawlak, M.; Szymański, M. K.; Skowron, J.; Mróz, P.; Kozłowski, S. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Collaboration: Spitzer team; OGLE group; and others

    2015-12-01

    We develop a new photometry algorithm that is optimized for the Infrared Array Camera (IRAC) Spitzer time series in crowded fields and that is particularly adapted to faint or heavily blended targets. We apply this to the 170 targets from the 2015 Spitzer microlensing campaign and present the results of three variants of this algorithm in an online catalog. We present detailed accounts of the application of this algorithm to two difficult cases, one very faint and the other very crowded. Several of Spitzer's instrumental characteristics that drive the specific features of this algorithm are shared by Kepler and WFIRST, implying that these features may prove to be a useful starting point for algorithms designed for microlensing campaigns by these other missions.

  1. Revisiting Legacy Software System Modernization

    NARCIS (Netherlands)

    Khadka, R.

    2016-01-01

    Legacy software systems are those that significantly resist modification and evolution while still being valuable to its stakeholders to the extent that their failure has a detrimental impact on business. Despite several drawbacks of legacy software systems, they are still being extensively used in

  2. Diffuse galactic annihilation radiation

    Science.gov (United States)

    Ramaty, R.; Lingenfelter, R. E.

    1993-01-01

    The study reports observations of positron annihilation radiation from the inner region of the Galaxy which show that there are two components of the radiation: a steady, diffuse Galactic component and a variable component from discrete, presumably compact sources. The existence of the variable component is supported by the ensemble of all narrow FOV 511 keV line observations, including recent detections with OSSE. The fit of this ensemble to a time-independent source distribution can be excluded at the approximately 3-sigma level. The same ensemble, combined with the broad FOV SMM observations of Galactic 511 keV line emission, sets constraints on the Galactic distribution of the diffuse component.

  3. Distant galactic open clusters

    International Nuclear Information System (INIS)

    Christian, C.A.

    1980-01-01

    The motivation for studying distant open clusters primarily arose out of a desire to gain some understanding of star formation processes in the general context of galactic structure. Of specific interest are faint open clusters near the galactic anticenter which are part of a larger survey of objects which may be located in the 'periphery' of the Galaxy. A sample of results from broad-band photometric studies for clusters near lsup(II)=180 0 , bsup(II)=0 0 is presented. (Auth.)

  4. LEGACY MANAGEMENT REQUIRES INFORMATION

    International Nuclear Information System (INIS)

    CONNELL, C.W.; HILDEBRAND, R.D.

    2006-01-01

    ''Legacy Management Requires Information'' describes the goal(s) of the US Department of Energy's Office of Legacy Management (LM) relative to maintaining critical records and the way those goals are being addressed at Hanford. The paper discusses the current practices for document control, as well as the use of modern databases for both storing and accessing the data to support cleanup decisions. In addition to the information goals of LM, the Hanford Federal Facility Agreement and Consent Order, known as the ''Tri-Party Agreement'' (TPA) is one of the main drivers in documentation and data management. The TPA, which specifies discrete milestones for cleaning up the Hanford Site, is a legally binding agreement among the US Department of Energy (DOE), the Washington State Department of Ecology (Ecology), and the US Environmental Protection Agency (EPA). The TPA requires that DOE provide the lead regulatory agency with the results of analytical laboratory and non-laboratory tests/readings to help guide them in making decisions. The Agreement also calls for each signatory to preserve--for at least ten years after the Agreement has ended--all of the records in its or its contractors, possession related to sampling, analysis, investigations, and monitoring conducted. The tools used at Hanford to meet TPA requirements are also the tools that can satisfy the needs of LM

  5. LEGACY MANAGEMENT REQUIRES INFORMATION

    Energy Technology Data Exchange (ETDEWEB)

    CONNELL, C.W.; HILDEBRAND, R.D.

    2006-12-14

    ''Legacy Management Requires Information'' describes the goal(s) of the US Department of Energy's Office of Legacy Management (LM) relative to maintaining critical records and the way those goals are being addressed at Hanford. The paper discusses the current practices for document control, as well as the use of modern databases for both storing and accessing the data to support cleanup decisions. In addition to the information goals of LM, the Hanford Federal Facility Agreement and Consent Order, known as the ''Tri-Party Agreement'' (TPA) is one of the main drivers in documentation and data management. The TPA, which specifies discrete milestones for cleaning up the Hanford Site, is a legally binding agreement among the US Department of Energy (DOE), the Washington State Department of Ecology (Ecology), and the US Environmental Protection Agency (EPA). The TPA requires that DOE provide the lead regulatory agency with the results of analytical laboratory and non-laboratory tests/readings to help guide them in making decisions. The Agreement also calls for each signatory to preserve--for at least ten years after the Agreement has ended--all of the records in its or its contractors, possession related to sampling, analysis, investigations, and monitoring conducted. The tools used at Hanford to meet TPA requirements are also the tools that can satisfy the needs of LM.

  6. SERENDIPITY OBSERVATIONS OF FAR INFRARED CIRRUS EMISSION IN THE SPITZER INFRARED NEARBY GALAXIES SURVEY: ANALYSIS OF FAR-INFRARED CORRELATIONS

    International Nuclear Information System (INIS)

    Bot, Caroline; Helou, George; Boulanger, Francois; Lagache, Guilaine; Miville-Deschenes, Marc-Antoine; Draine, Bruce; Martin, Peter

    2009-01-01

    We present an analysis of far-infrared (FIR) dust emission from diffuse cirrus clouds. This study is based on serendipitous observations at 160 μm at high-galactic latitude with the Multiband Imaging Photometer onboard the Spitzer Space Telescope by the Spitzer Infrared Nearby Galaxies Survey. These observations are complemented with IRIS data at 100 and 60 μm and constitute one of the most sensitive and unbiased samples of FIR observations at a small scale of diffuse interstellar clouds. Outside regions dominated by the cosmic infrared background fluctuations, we observe a substantial scatter in the 160/100 colors from cirrus emission. We compared the 160/100 color variations to 60/100 colors in the same fields and find a trend of decreasing 60/100 with increasing 160/100. This trend cannot be accounted for by current dust models by changing solely the interstellar radiation field. It requires a significant change of dust properties such as grain size distribution or emissivity or a mixing of clouds in different physical conditions along the line of sight. These variations are important as a potential confusing foreground for extragalactic studies.

  7. Continuing galactic formation

    International Nuclear Information System (INIS)

    McCanney, J.M.

    1981-01-01

    A new theory for galactic arm formation shows the arms to be continually eminating from the galactic nucleus due to a continual influx of cosmic dust. In the neighborhood of the nucleus the problem is treated as a fluid flow and a simple solution is given using conservation of momentum. When rotational dynamics are included the spinning arm system is the result. This solution resolves the problem of the missing mass, accounts for warped disk galaxies and gives a probable source for the gravity waves measured by Weber which eminate from our galactic center. Reversal of arm direction is demonstrated and examples of such reversals are cited. An approximate theoretical estimate of the age of our Sun is found to be in good agreement with radio isotope dating. A general result shows why twin star systems are in such great abundance in a galaxy. It gives a model of galactic evolution which begins with only a single massive nucleus with the collapsing gas clouds forming the arms. (orig.)

  8. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-01-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of

  9. ExploreNEOs: The Warm Spitzer Near Earth Object Survey

    NARCIS (Netherlands)

    Trilling, D. E.; Hora, J. L.; Mueller, M.; Thomas, C. A.; Harris, A. W.; Hagen, A. R.; Mommert, M.; Benner, L.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Delbo, M.; Emery, J. P.; Fazio, G.; Kistler, J. L.; Mainzer, A.; Morbidelli, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.

    2012-01-01

    We have observed some 600 near Earth objects (NEOs) at 3.6 and 4.5 microns with the Warm Spitzer Space Telescope. We derive the albedo and diameter for each NEO to characterize global properties of the NEO population, among other goals.

  10. Robert Spitzer and psychiatric classification: technical challenges and ethical dilemmas.

    Science.gov (United States)

    Jacob, K S

    2016-01-01

    Dr Robert Leopold Spitzer (May 22, 1932-December 25, 2015), the architect of modern psychiatric diagnostic criteria and classification, died recently at the age of 83 in Seattle. Under his leadership, the American Psychiatric Association's (APA) Diagnostic and Statistical Manuals (DSM) became the international standard.

  11. SPITZER OBSERVATIONS OF EXTENDED LYMAN-α CLOUDS IN THE SSA22 FIELD

    International Nuclear Information System (INIS)

    Webb, T. M. A.; Gonzalez, M.; Yamada, T.; Huang, J.-S.; Ashby, M. L. N; Matsuda, Y.; Egami, E.; Hayashimo, T.

    2009-01-01

    We present the results of a Spitzer IRAC and MIPS 24 μm study of extended Lyman-α clouds (or Lyman-α Blobs, LABs) within the SSA22 filamentary structure at z = 3.09. We detect 6/26 LABs in all IRAC filters, four of which are also detected at 24 μm, and find good correspondence with the 850 μm measurements of Geach et al. An analysis of the rest-frame ultraviolet, optical, near- and mid-infrared colors reveals that these six systems exhibit signs of nuclear activity (active galactic nucleus (AGN)) and/or extreme star formation. Notably, they have properties that bridge galaxies dominated by star formation (Lyman-break galaxies (LBGs)) and those with AGNs (LBGs classified as QSOs). The LAB systems not detected in all four IRAC bands, on the other hand, are, as a group, consistent with pure star-forming systems, similar to the majority of the LBGs within the filament. These results indicate that the galaxies within LABs do not comprise a homogeneous population, though they are also consistent with scenarios in which the gas halos are ionized through a common mechanism such as galaxy-scale winds driven by the galaxies within them, or gravitational heating of the collapsing cloud itself.

  12. Till Moritz Karbach, Scientific Legacy

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassi, Guido; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; d'Argent, Philippe; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Bellee, Violaine; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Birnkraut, Alex; Bizzeti, Andrea; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Demmer, Moritz; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Di Ruscio, Francesco; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fohl, Klaus; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gastaldi, Ugo; Gauld, Rhorry; Gavardi, Laura; Gazzoni, Giulio; Geraci, Angelo; Gerick, David; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Girard, Olivier Göran; Giubega, Lavinia-Helena; Gligorov, Vladimir; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graverini, Elena; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadavizadeh, Thomas; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Humair, Thibaud; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Kenzie, Matthew; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozeiha, Mohamad; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kuonen, Axel Kevin; Kurek, Krzysztof; Kvaratskheliya, Tengiz; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Liu, Xuesong; Loh, David; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lowdon, Peter; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Maciuc, Florin; Maev, Oleg; Maguire, Kevin; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Manning, Peter Michael; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martin, Morgan; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathad, Abhijit; Mathe, Zoltan; Matteuzzi, Clara; Mauri, Andrea; Maurin, Brice; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; Meadows, Brian; Meier, Frank; Meissner, Marco; Melnychuk, Dmytro; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Mitzel, Dominik Stefan; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Janine; Müller, Katharina; Müller, Vanessa; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nandi, Anita; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Ninci, Daniele; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Osorio Rodrigues, Bruno; Otalora Goicochea, Juan Martin; Otto, Adam; Owen, Patrick; Oyanguren, Maria Aranzazu; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Pappenheimer, Cheryl; Parkes, Christopher; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pearce, Alex; Pellegrino, Antonio; Penso, Gianni; Pepe Altarelli, Monica; Perazzini, Stefano; Perret, Pascal; Pescatore, Luca; Petridis, Konstantinos; Petrolini, Alessandro; Petruzzo, Marco; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Piucci, Alessio; Playfer, Stephen; Plo Casasus, Maximo; Poikela, Tuomas; Polci, Francesco; Poluektov, Anton; Polyakov, Ivan; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Quagliani, Renato; Rachwal, Bartolomiej; Rademacker, Jonas; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Lopez, Jairo Alexis; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Ronayne, John William; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santimaria, Marco; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmelzer, Timon; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schubiger, Maxime; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Semennikov, Alexander; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skillicorn, Ian; Skwarnicki, Tomasz; Smith, Edmund; Smith, Eluned; Smith, Iwan Thomas; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Sterpka, Christopher Francis; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szumlak, Tomasz; T'Jampens, Stephane; Tekampe, Tobias; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Todd, Jacob; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Trabelsi, Karim; Tran, Minh Tâm; Tresch, Marco; Trisovic, Ana; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Weiden, Andreas; Whitehead, Mark; Wiedner, Dirk; Wilkinson, Guy; Wilkinson, Michael; Williams, Mark Richard James; Williams, Matthew; Williams, Mike; Williams, Timothy; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xu, Zhirui; Yang, Zhenwei; Yu, Jiesheng; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang

    2015-01-01

    We are deeply touched by the sudden loss of our dear friend and colleague Till Moritz Karbach. With this memorial book we wish to commemorate Moritz’ scientific legacy, and what Moritz meant to us as a friend.

  13. Modeling galactic extinction

    OpenAIRE

    Cecchi-Pestellini, C.; Mulas, G.; Casu, S.; Iatì, M. A.; Saija, R.; Cacciola, A.; Borghese, F.; Denti, P.

    2011-01-01

    We present a model for interstellar extinction dust, in which we assume a bimodal distribution of extinction carriers, a dispersion of core-mantle grains, supplemented by a collection of PAHs in free molecular form. We use state-of-the-art methods to calculate the extinction due to macroscopic dust particles, and the absorption cross-sections of PAHs in four different charge states. While successfull for most of observed Galactic extinction curves, in few cases the model cannot provide reliab...

  14. Transition from galactic to extra-galactic cosmic rays

    International Nuclear Information System (INIS)

    Aloisio, Roberto

    2006-01-01

    In this paper we review the main features of the observed Cosmic Rays spectrum in the energy range 10 17 eV to 10 20 eV. We present a theoretical model that explains the main observed features of the spectrum, namely the second Knee and Dip, and implies a transition from Galactic to Extra-Galactic cosmic rays at energy E ≅ 10 18 eV, with a proton dominated Extra-Galactic spectrum

  15. Early 2017 observations of TRAPPIST-1 with Spitzer

    Science.gov (United States)

    Delrez, L.; Gillon, M.; Triaud, A. H. M. J.; Demory, B.-O.; de Wit, J.; Ingalls, J. G.; Agol, E.; Bolmont, E.; Burdanov, A.; Burgasser, A. J.; Carey, S. J.; Jehin, E.; Leconte, J.; Lederer, S.; Queloz, D.; Selsis, F.; Van Grootel, V.

    2018-04-01

    The recently detected TRAPPIST-1 planetary system, with its seven planets transiting a nearby ultracool dwarf star, offers the first opportunity to perform comparative exoplanetology of temperate Earth-sized worlds. To further advance our understanding of these planets' compositions, energy budgets, and dynamics, we are carrying out an intensive photometric monitoring campaign of their transits with the Spitzer Space Telescope. In this context, we present 60 new transits of the TRAPPIST-1 planets observed with Spitzer/Infrared Array Camera (IRAC) in 2017 February and March. We combine these observations with previously published Spitzer transit photometry and perform a global analysis of the resulting extensive data set. This analysis refines the transit parameters and provides revised values for the planets' physical parameters, notably their radii, using updated properties for the star. As part of our study, we also measure precise transit timings that will be used in a companion paper to refine the planets' masses and compositions using the transit timing variations method. TRAPPIST-1 shows a very low level of low-frequency variability in the IRAC 4.5-μm band, with a photometric RMS of only 0.11 per cent at a 123-s cadence. We do not detect any evidence of a (quasi-)periodic signal related to stellar rotation. We also analyse the transit light curves individually, to search for possible variations in the transit parameters of each planet due to stellar variability, and find that the Spitzer transits of the planets are mostly immune to the effects of stellar variations. These results are encouraging for forthcoming transmission spectroscopy observations of the TRAPPIST-1 planets with the James Webb Space Telescope.

  16. SPITZER SPACE TELESCOPE MID-IR LIGHT CURVES OF NEPTUNE

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, John; Rebull, Luisa; Carey, Sean J.; Krick, Jessica; Ingalls, James G.; Lowrance, Patrick; Glaccum, William [Spitzer Science Center (SSC), California Institute of Technology, Pasadena, CA 91125 (United States); Marley, Mark S. [NASA Ames Research Center, Space Sciences and Astrobiology Division, MS245-3, Moffett Field, CA 94035 (United States); Gizis, John E. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Kirkpatrick, J. Davy [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Simon, Amy A. [NASA Goddard Space Flight Center, Solar System Exploration Division (690.0), 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Wong, Michael H. [University of California, Department of Astronomy, Berkeley CA 94720-3411 (United States)

    2016-11-01

    We have used the Spitzer Space Telescope in 2016 February to obtain high cadence, high signal-to-noise, 17 hr duration light curves of Neptune at 3.6 and 4.5 μ m. The light curve duration was chosen to correspond to the rotation period of Neptune. Both light curves are slowly varying with time, with full amplitudes of 1.1 mag at 3.6 μ m and 0.6 mag at 4.5 μ m. We have also extracted sparsely sampled 18 hr light curves of Neptune at W1 (3.4 μ m) and W2 (4.6 μ m) from the Wide-feld Infrared Survey Explorer ( WISE )/ NEOWISE archive at six epochs in 2010–2015. These light curves all show similar shapes and amplitudes compared to the Spitzer light curves but with considerable variation from epoch to epoch. These amplitudes are much larger than those observed with Kepler / K 2 in the visible (amplitude ∼0.02 mag) or at 845 nm with the Hubble Space Telescope ( HST ) in 2015 and at 763 nm in 2016 (amplitude ∼0.2 mag). We interpret the Spitzer and WISE light curves as arising entirely from reflected solar photons, from higher levels in Neptune’s atmosphere than for K 2. Methane gas is the dominant opacity source in Neptune’s atmosphere, and methane absorption bands are present in the HST 763 and 845 nm, WISE W1, and Spitzer 3.6 μ m filters.

  17. The Galactic metallicity gradient

    Science.gov (United States)

    Rolleston, W. R. J.; Smartt, S. J.; Dufton, P. L.; Ryans, R. S. I.

    2000-11-01

    We have previously published intermediate to high resolution spectroscopic observations of approximately 80 early B-type main-sequence stars situated in 19 Galactic open clusters/associations with Galactocentric distances distributed over 6Twarog et al. \\cite{twa97}). However, there is no evidence to suggest that our data would be better fitted with a two-zone model. Moreover, we observe a N/O gradient of -0.04+/-0.02 dex kpc-1 which is consistent with that found for other spiral galaxies (Vila-Costas & Edmunds \\cite{vil93}).

  18. Active galactic nuclei

    CERN Document Server

    Blandford, RD; Woltjer, L

    1990-01-01

    Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory

  19. THE SPITZER SURVEY OF INTERSTELLAR CLOUDS IN THE GOULD BELT. IV. LUPUS V AND VI OBSERVED WITH IRAC AND MIPS

    International Nuclear Information System (INIS)

    Spezzi, Loredana; Vernazza, Pierre; Merin, Bruno; Allen, Lori E.; Evans, Neal J. II; Harvey, Paul M.; Joergensen, Jes K.; Bourke, Tyler L.; Peterson, Dawn; Cieza, Lucas A.; Dunham, Michael M.; Huard, Tracy L.; Tothill, Nick F. H.

    2011-01-01

    We present Gould's Belt (GB) Spitzer IRAC and MIPS observations of the Lupus V and VI clouds and discuss them in combination with near-infrared (2MASS) data. Our observations complement those obtained for other Lupus clouds within the frame of the Spitzer C ore to Disk(c2d) Legacy Survey. We found 43 young stellar object (YSO) candidates in Lupus V and 45 in Lupus VI, including two transition disks, using the standard c2d/GB selection method. None of these sources was classified as a pre-main-sequence star from previous optical, near-IR, and X-ray surveys. A large majority of these YSO candidates appear to be surrounded by thin disks (Class III; ∼79% in Lupus V and ∼87% in Lupus VI). These Class III abundances differ significantly from those observed for the other Lupus clouds and c2d/GB surveyed star-forming regions, where objects with optically thick disks (Class II) dominate the young population. We investigate various scenarios that can explain this discrepancy. In particular, we show that disk photoevaporation due to nearby OB stars is not responsible for the high fraction of Class III objects. The gas surface densities measured for Lupus V and VI lie below the star formation threshold (A V ∼ 8.6 mag), while this is not the case for other Lupus clouds. Thus, few Myr older age for the YSOs in Lupus V and VI with respect to other Lupus clouds is the most likely explanation of the high fraction of Class III objects in these clouds, while a higher characteristic stellar mass might be a contributing factor. Better constraints on the age and binary fraction of the Lupus clouds might solve the puzzle but require further observations.

  20. The Chandra Galactic Bulge Survey

    NARCIS (Netherlands)

    Hynes, Robert I.; Jonker, P.G.; Bassa, C. G.; Dieball, A.; Greiss, S.; Maccarone, T. J.; Nelemans, G.; Steeghs, D.; Torres, M. A. P.; Britt, C. T.; Clem, J. L.; Gossen, L.; Grindlay, J. E.; Groot, P.J.; Kuiper, L.; Kuulkers, E.; Mendez, M.; Mikles, V. J.; Ratti, E. M.; Rea, N.; van Haaften, L.; Wijnands, R.; in't Zand, J. J. M.

    The Chandra Galactic Bulge Survey (CGBS) is a shallow but wide survey of two approximately 6x1 degree strips of the Galactic Bulge about a degree above and below the plane. The survey by design targets regions where extinction and crowding are manageable and optical counterparts are accessible to

  1. The Chandra Galactic Bulge Survey

    NARCIS (Netherlands)

    Hynes, Robert I.; Jonker, P. G.; Bassa, C. G.; Nelemans, G.; Steeghs, D.; Torres, M. A. P.; Maccarone, T. J.; Greiss, S.; Clem, J.; Dieball, A.; Mikles, V. J.; Britt, C. T.; Gossen, L.; Collazzi, A. C.; Wijnands, R.; In't Zand, J. J. M.; Mendez, M.; Rea, N.; Kuulkers, E.; Ratti, E. M.; van Haaften, L. M.; Heinke, C.; Ozel, F.; Groot, P. J.; Verbunt, F.

    2012-01-01

    The Chandra Galactic Bulge Survey (GBS) is a shallow but wide survey of two approximately 6x1 degree strips of the Galactic Bulge about a degree above and below the plane. The survey by design targets regions where extinction and crowding are manageable and optical counterparts are accessible to

  2. The Chandra Galactic Bulge Survey

    NARCIS (Netherlands)

    Hynes, Robert I.; Jonker, P. G.; Bassa, C. G.; Nelemans, G.; Steeghs, D.; Torres, M. A. P.; Maccarone, T. J.; Greiss, S.; Clem, J.; Dieball, A.; Mikles, V. J.; Britt, C. T.; Gossen, L.; Collazzi, A. C.; Wijnands, R.; In't Zand, J. J. M.; Mendez, M.; Rea, N.; Kuulkers, E.; Ratti, E. M.; van Haaften, L. M.; Heinke, C.; Ozel, F.; Groot, P. J.; Verbunt, F.

    The Chandra Galactic Bulge Survey (GBS) is a shallow but wide survey of two approximately 6x1 degree strips of the Galactic Bulge about a degree above and below the plane. The survey by design targets regions where extinction and crowding are manageable and optical counterparts are accessible to

  3. The Legacy of Nikola Tesla

    Indian Academy of Sciences (India)

    Srimath

    and problems of rural power situation in India. Writing books of science for children is his major preoccupation now. The Legacy of Nikola Tesla. 2. AC Power System and its Growth in India. D P Sen Gupta. Electrical power supply has grown enormously during this century. In 1950 the total capacity of generators producing.

  4. Exploring legacy systems using types

    NARCIS (Netherlands)

    A. van Deursen (Arie); L.M.F. Moonen (Leon)

    2000-01-01

    textabstractWe show how hypertext-based program understanding tools can achieve new levels of abstraction by using inferred type information for cases where the subject software system is written in a weakly typed language. We propose TypeExplorer, a tool for browsing COBOL legacy systems based on

  5. The Olympic legacy: feeding London

    NARCIS (Netherlands)

    Janssens, F.

    2012-01-01

    Over the last decades, the Olympic Games have increasingly claimed to deliver a social and economic ‘legacy’ to the host city. The 2012 Olympic Games in London have set out to deliver a legacy of better food for east London, an area perceived as ‘deprived’, with higher than average rates of obesity

  6. Einstein's Legacy, at the Globe

    CERN Multimedia

    2005-01-01

    One-hundred years on, Albert Einstein's theories continue to fuel the daily work of physicists. From research into gravity waves to the quest for grand unification in physics, today's researchers have not finished with the legacy of the most famous and iconic physicist of the 20th Century.

  7. The Legacy of Nikola Tesla

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 4. The Legacy of Nikola Tesla - AC Power System and its Growth in India. D P Sen Gupta. General Article Volume 12 Issue 4 April 2007 pp 69-79. Fulltext. Click here to view fulltext PDF. Permanent link:

  8. Understanding Legacy Features with Featureous

    DEFF Research Database (Denmark)

    Olszak, Andrzej; Jørgensen, Bo Nørregaard

    2011-01-01

    Feature-centric comprehension of source code is essential during software evolution. However, such comprehension is oftentimes difficult to achieve due the discrepancies between structural and functional units of object-oriented programs. We present a tool for feature-centric analysis of legacy...

  9. The Legacy of Nikola Tesla

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 3. The Legacy of Nikola Tesla - The AC System that he Helped to Usher in. D P Sen Gupta. General Article Volume 12 Issue 3 March 2007 pp 54-69. Fulltext. Click here to view fulltext PDF. Permanent link:

  10. The Legacy of S Chandrasekhar

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 4. The Legacy of S. Chandrasekhar Remembering a Giant of Our Times. Kameshwar C Wali. General Article Volume 2 Issue 4 April 1997 pp 19-24. Fulltext. Click here to view fulltext PDF. Permanent link:

  11. From Event Planning to Legacy Planning

    OpenAIRE

    Elo, Lauri

    2016-01-01

    The importance of legacy and legacy planning is increasing in the event industry. Mega-events are becoming so expensive to host that the opportunity costs decreases the amount of potential future hosts. The events aim to surpass the costs by creating positive legacies, impacts that last longer than the event itself. Small-events can also have legacies and the positive affects can be even more significant than with the mega-events. Event planning must change to legacy planning in the future, b...

  12. Dust Processing in Supernova Remnants: Spitzer MIPS SED and IRS Observations

    Science.gov (United States)

    Hewitt, John W.; Petre, Robert; Katsuda Satoru; Andersen, M.; Rho, J.; Reach, W. T.; Bernard, J. P.

    2011-01-01

    We present Spitzer MIPS SED and IRS observations of 14 Galactic Supernova Remnants previously identified in the GLIMPSE survey. We find evidence for SNR/molecular cloud interaction through detection of [OI] emission, ionic lines, and emission from molecular hydrogen. Through black-body fitting of the MIPS SEDs we find the large grains to be warm, 29-66 K. The dust emission is modeled using the DUSTEM code and a three component dust model composed of populations of big grains, very small grains, and polycyclic aromatic hydrocarbons. We find the dust to be moderately heated, typically by 30-100 times the interstellar radiation field. The source of the radiation is likely hydrogen recombination, where the excitation of hydrogen occurred in the shock front. The ratio of very small grains to big grains is found for most of the molecular interacting SNRs to be higher than that found in the plane of the Milky Way, typically by a factor of 2--3. We suggest that dust shattering is responsible for the relative over-abundance of small grains, in agreement with prediction from dust destruction models. However, two of the SNRs are best fit with a very low abundance of carbon grains to silicate grains and with a very high radiation field. A likely reason for the low abundance of small carbon grains is sputtering. We find evidence for silicate emission at 20 $\\mu$m in their SEDs, indicating that they are young SNRs based on the strong radiation field necessary to reproduce the observed SEDs.

  13. Measurement of the Transverse Spitzer Resistivity during Collisional Magnetic Reconnection

    International Nuclear Information System (INIS)

    Trintchouk, F.; Yamada, M.; Ji, H.; Kulsrud, R.M.; Carter, T.A.

    2000-01-01

    Measurement of the transverse resistivity was carried out in a reconnecting current sheet where the mean free path for the Coulomb collision is smaller than the thickness of the sheet. In a collisional neutral sheet without a guide field, the transverse resistivity is directly related to the reconnection rate. A remarkable agreement is found between the measured resistivity and the classical value derived by L. Spitzer. In his calculation the transverse resistivity for the electrons is higher than the parallel resistivity by a factor of 1.96. The measured values have verified this theory to within 30% errors

  14. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    Science.gov (United States)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-09-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of archived MIPS observations of Phoebe reproduces Cassini results very accurately, thereby validating our method. For all targets, the geometric albedo is found to be low, probably below 10% and clearly below 15%. Irregular satellites are much darker than the large regular satellites. Their albedo is, however, quite similar to that of small bodies in the outer Solar System (such as cometary nuclei, Jupiter Trojans, or TNOs). This is consistent with color measurements as well as dynamical considerations which suggest a common origin of the said populations. There appear to be significant object-to-object albedo differences. Similar albedos found for some members of dynamical clusters support the idea that they may have originated in the breakup of a parent body. For three satellites, thermal data at two wavelengths are available, enabling us to constrain their thermal properties. Sub-solar temperatures are similar to that found from Cassini's Phoebe fly-by. This suggests a rather low thermal inertia, as expected for regolith-covered objects. This work is based on observations made with the Spitzer Space Telescope, which is operated by JPL under a contract with NASA. Support for this work was provided by NASA.

  15. Albedo and Diameter Distributions of Asteroid Families Using the Spitzer Asteroid Catalog

    NARCIS (Netherlands)

    Enga, Marie-Therese; Trilling, D.; Mueller, M.; Wasserman, L.; Sykes, M.; Blaylock, M.; Stansberry, J.; Bhattacharya, B.; Spahr, T.

    2009-01-01

    The Spitzer Asteroid Catalog contains flux measurements of asteroidsserendipitously observed in publicly available Spitzer data. At present,this catalog contains some 10,000 measurements at 24 microns only, andwill ultimately contain 100,000 measurements or more. These measurements, along with with

  16. Multiple asteroid systems : Dimensions and thermal properties from Spitzer Space Telescope and ground-based observations

    NARCIS (Netherlands)

    Marchis, F.; Enriquez, J. E.; Emery, J. P.; Mueller, M.; Baek, M.; Pollock, J.; Assafin, M.; Vieira Martins, R.; Berthier, J.; Vachier, F.; Cruikshank, D. P.; Lim, L. F.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; LaCluyze, A. P.

    2012-01-01

    We collected mid-IR spectra from 5.2 to 38 μm using the Spitzer Space Telescope Infrared Spectrograph of 28 asteroids representative of all established types of binary groups. Photometric lightcurves were also obtained for 14 of them during the Spitzer observations to provide the context of the

  17. MALT 90: The Millimeter Astronomy Legacy Team 90 GHz Survey

    Science.gov (United States)

    Jackson, James M.; Foster, J.; Brooks, K.; Rathborne, J.; Longmore, S.

    2011-05-01

    We present the first season results of the Millimeter Astronomy Legacy Team 90 GHz Survey (MALT90), which will image 3 mm molecular line emission from 3,000 dense star-forming cores. MALT90 exploits the capability of the ATNF Mopra 22 m telescope for fast mapping and simultaneous imaging of 16 molecular lines near 90 GHz. These molecular lines will probe the cores’ physical, chemical, and evolutionary state. The target cores are selected from the 870 micron ATLASGAL survey to host the early stages of high-mass star formation and to span the complete range of evolutionary states from pre-stellar cores, to protostellar cores, and on to H II regions. Each core will be mapped at excellent angular (40'') and spectral (0.1 km/s) resolution. We present preliminary results for four key science projects: (1) determining the kinematic distances and Galactic distribution of dense cores, (2) establishing the distribution and evolution of angular momentum in a large sample of high-mass cores, (3) investigating the chemical evolution of dense cores, and (4) comparing the extragalactic molecular line-infrared luminosity correlations with those in Galactic cores. MALT90 will provide the definitive source list of high-mass dense cores for ALMA.

  18. On the mid-infrared variability of candidate eruptive variables (exors): A comparison between Spitzer and WISE data

    Energy Technology Data Exchange (ETDEWEB)

    Antoniucci, S.; Giannini, T.; Li Causi, G.; Lorenzetti, D., E-mail: simone.antoniucci@oa-roma.inaf.it, E-mail: teresa.giannini@oa-roma.inaf.it, E-mail: gianluca.licausi@oa-roma.inaf.it, E-mail: dario.lorenzetti@oa-roma.inaf.it [INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monte Porzio (Italy)

    2014-02-10

    Aiming to statistically study the variability in the mid-IR of young stellar objects, we have compared the 3.6, 4.5, and 24 μm Spitzer fluxes of 1478 sources belonging to the C2D (Cores to Disks) legacy program with the WISE fluxes at 3.4, 4.6, and 22 μm. From this comparison, we have selected a robust sample of 34 variable sources. Their variations were classified per spectral Class (according to the widely accepted scheme of Class I/flat/II/III protostars), and per star forming region. On average, the number of variable sources decreases with increasing Class and is definitely higher in Perseus and Ophiuchus than in Chamaeleon and Lupus. According to the paradigm Class ≡ Evolution, the photometric variability can be considered to be a feature more pronounced in less evolved protostars, and, as such, related to accretion processes. Moreover, our statistical findings agree with the current knowledge of star formation activity in different regions. The 34 selected variables were further investigated for similarities with known young eruptive variables, namely the EXors. In particular, we analyzed (1) the shape of the spectral energy distribution, (2) the IR excess over the stellar photosphere, (3) magnitude versus color variations, and (4) output parameters of model fitting. This first systematic search for EXors ends up with 11 bona fide candidates that can be considered as suitable targets for monitoring or future investigations.

  19. Book Review: Galactic Encounters

    Energy Technology Data Exchange (ETDEWEB)

    Balasis, Georgios, E-mail: gbalasis@noa.gr [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Athens (Greece)

    2016-05-23

    Galactic Encounters” by Sheehan and Conselice provides a view of galaxies telling the story of how astronomers have pieced together what is known about the modern view of the Universe. The book helps the reader to understand “why” we know what we do, not simply “what,” starting with the development of the telescope that coincides with the modern picture of the Universe. William Sheehan is a noted historian of astronomy but also a Doctor of Medicine, specializing in psychiatry. In this perspective, he has a unique insight into the personalities of the pioneering figures of the history of science. Christopher Conselice is a Professor of Astrophysics at the University of Nottingham, who studies the formation of galaxies, addressing the issue of “how” rather than “when” galaxies form. Reading the book, amateur astronomers would have been able to feel what actually drives them: “it is the desire to participate in this vast universe, in their own small way,…and not let the experts do everything for them.” I have to admit that I have also quite enjoyed the author's remark pertinent to the history and philosophy of science about the distinction, nowadays, between “polymaths” and “monomaths.”.

  20. Book Review: Galactic Encounters

    International Nuclear Information System (INIS)

    Balasis, Georgios

    2016-01-01

    Galactic Encounters” by Sheehan and Conselice provides a view of galaxies telling the story of how astronomers have pieced together what is known about the modern view of the Universe. The book helps the reader to understand “why” we know what we do, not simply “what,” starting with the development of the telescope that coincides with the modern picture of the Universe. William Sheehan is a noted historian of astronomy but also a Doctor of Medicine, specializing in psychiatry. In this perspective, he has a unique insight into the personalities of the pioneering figures of the history of science. Christopher Conselice is a Professor of Astrophysics at the University of Nottingham, who studies the formation of galaxies, addressing the issue of “how” rather than “when” galaxies form. Reading the book, amateur astronomers would have been able to feel what actually drives them: “it is the desire to participate in this vast universe, in their own small way,…and not let the experts do everything for them.” I have to admit that I have also quite enjoyed the author's remark pertinent to the history and philosophy of science about the distinction, nowadays, between “polymaths” and “monomaths.”

  1. Galactic planetary science.

    Science.gov (United States)

    Tinetti, Giovanna

    2014-04-28

    Planetary science beyond the boundaries of our Solar System is today in its infancy. Until a couple of decades ago, the detailed investigation of the planetary properties was restricted to objects orbiting inside the Kuiper Belt. Today, we cannot ignore that the number of known planets has increased by two orders of magnitude nor that these planets resemble anything but the objects present in our own Solar System. Whether this fact is the result of a selection bias induced by the kind of techniques used to discover new planets--mainly radial velocity and transit--or simply the proof that the Solar System is a rarity in the Milky Way, we do not know yet. What is clear, though, is that the Solar System has failed to be the paradigm not only in our Galaxy but even 'just' in the solar neighbourhood. This finding, although unsettling, forces us to reconsider our knowledge of planets under a different light and perhaps question a few of the theoretical pillars on which we base our current 'understanding'. The next decade will be critical to advance in what we should perhaps call Galactic planetary science. In this paper, I review highlights and pitfalls of our current knowledge of this topic and elaborate on how this knowledge might arguably evolve in the next decade. More critically, I identify what should be the mandatory scientific and technical steps to be taken in this fascinating journey of remote exploration of planets in our Galaxy.

  2. Legacies of the Manhattan Project

    Science.gov (United States)

    Kevles, Daniel

    2017-01-01

    The Manhattan Project of World War II mobilized thousands of people, including many of the nation's leading physicists, and extensive material resources to design, develop, and manufacture the world's first nuclear weapons. It also established sprawling new facilities for the production of fissionable fuels - notably at Oak Ridge, Tennessee, and Hanford, Washington. It left a set of powerful legacies in the context of the Cold War - endowing scientists with conscience-taxing responsibilities in the nuclear arms race; promoting enormous patronage of academic research by defense and defense-related federal agencies, notably the Office of Naval Research and the Atomic Energy Commission; and turning its wartime facilities into major national laboratories that advanced the fields of high-energy and nuclear physics and stimulated local industrial economies but that in some cases, notably at Hanford, severely polluted the surrounding environment with radioactive waste and disrupted the livelihoods of native peoples. ``Legacies of the Manhattan Project''

  3. Unusual Slowly Rotating Brown Dwarfs Discovered through Precision Spitzer Photometry

    Science.gov (United States)

    Heinze, Aren; Metchev, S.

    2014-01-01

    Many brown dwarfs exhibit low-amplitude rotationally modulated variability due to photospheric inhomogeneities caused by condensate clouds in their atmospheres. The Spitzer Space Telescope 'Weather on Other Worlds' (WoW) project has monitored 44 brown dwarfs at unprecedented photometric precision from space. We present one of several important new results from WoW: the discovery of brown dwarfs with unexpectedly slow rotation periods. While most brown dwarfs have periods of 2-12 hours, we have identified two with well-constrained periods of 13±1 and >20 hours, respectively, and 2 others that show more tentative evidence of longer than 20-hour periods. By serving as almost non-rotating standards, these objects will allow more accurate calibration of spectroscopic measurements of brown dwarfs' projected rotational velocities. The existence of such slowly-rotating objects also constrains models of brown dwarf formation and angular momentum evolution.

  4. Polycyclic Aromatic Hydrocarbons and Infrared Astrophysics with Spitzer

    Science.gov (United States)

    Hudgins, Douglas M.; Allamandola, L. J.

    2004-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role that carbon-rich plays in the interstellar medium (ISM). Twenty years ago, the possible existence of an abundant population of large, carbon-rich molecules in the ISM was unthinkable. Today, the unmistakable spectroscopic signatures of polycyclic aromatic hydrocarbons (PAHs) - shockingly large molecules by the standards of traditional interstellar chemistry -are recognized throughout the Universe. In this presentation, we will examine the current state of the interstellar PAH model and explore how this data, in conjunction with the unparalleled observational data provided by the Spitzer Space Telescope, can be used to draw ever-deeper insights into the physical and chemical natures of a wide range of astrophysical environments.

  5. Repurposing legacy data innovative case studies

    CERN Document Server

    Berman, Jules J

    2015-01-01

    Repurposing Legacy Data: Innovative Case Studies takes a look at how data scientists have re-purposed legacy data, whether their own, or legacy data that has been donated to the public domain. Most of the data stored worldwide is legacy data-data created some time in the past, for a particular purpose, and left in obsolete formats. As with keepsakes in an attic, we retain this information thinking it may have value in the future, though we have no current use for it. The case studies in this book, from such diverse fields as cosmology, quantum physics, high-energy physics, microbiology,

  6. Dust and Gas in Different Galactic Environments

    Science.gov (United States)

    Goncalves, Daniela Catarina Pinheiro

    2014-01-01

    This thesis encompasses the study of the mid-infrared (IR) dust properties in diffuse high latitude cirrus and in the dense environments of supernova remnants (SNRs) in the plane of our Galaxy. Unlike the well known emission properties of dust grains in the diffuse ISM in the far-IR and submillimeter, the mid-IR spectrum is still relatively unconstrained. We extend the correlation of dust emission with H I column densities to mid-IR wavelengths and look for evidence of variations in the emissivity of dust associated with local and halo gas. This is accomplished by spatially correlating the IR maps from the IRIS/IRAS survey at 12, 25, 60 and 100 μm with H I column density maps inferred from 21-cm line emission observations obtained with the GBT (at a 9' resolution). We find that IVCs (halo clouds thought to be part of the Galactic fountain) show color ratios consistent with a dust evolution scenario in which large dust grains are shattered into smaller ones (VSGs). The low 12 μm emission found suggests a reduced abundance of PAHs in IVCs. We also address the IR extragalactic emission seen in our residual maps and quantify its power spectrum behaviour. Continuing with the mid-IR theme, we conducted a comprehensive study of the morphology and energetics of SNRs in the plane of our Galaxy. We make use of the Spitzer MIPSGAL (at 24 and 70 μm) and GLIMPSE (at 8 μm) surveys to detected infrared counterparts to SNR candidates in Green's catalog. We find that a third of the sample shows IR emission and calculate the corresponding fluxes. We explore the relation between IR colors to place constraints on the different IR SNRs emission mechanisms. Aided by archival radio data, we find that most candidates detected show IR-to-radio ratios consistent with SNRs with a few exceptions displaying ratios seen in H II regions. Finally, we explore the connection between the IR and the high-energy X-ray emission of SNRs and find a good morphological association between the 24

  7. Young Stars in the Camelopardalis Dust and Molecular Clouds. VI. YSOs Verified by Spitzer and Akari Infrared Photometry

    Directory of Open Access Journals (Sweden)

    Straižys V.

    2010-06-01

    Full Text Available Using photometric data of infrared surveys, young stellar object (YSO status is verified for 141 objects selected in our previous papers in the Cassiopeia and Camelopardalis segment of the Milky Way bounded by Galactic coordinates (l, b = (132-158°, ±12°. The area includes the known star- forming regions in the emission nebulae W3, W4 and W5 and the massive YSO AFGL490. Spectral energy distribution (SED curves between 700 nm and 160 μm, constructed from the GSC 2, 2MASS, IRAS, MSX, Spitzer and AKARI data, are used to estimate the evolutionary stages of these stars. We confirm the YSO status for most of the objects. If all of the investigated objects were YSOs, 45% of them should belong to Class I, 41% to class II and 14% to Class III. However, SEDs of some of these objects can be affected by nearby extended infrared sources, like compact H II regions, infrared clusters or dusty galaxies.

  8. Observing the Next Galactic Supernova

    Science.gov (United States)

    Adams, Scott M.; Kochanek, C. S.; Beacom, John F.; Vagins, Mark R.; Stanek, K. Z.

    2013-12-01

    No supernova (SN) in the Milky Way has been observed since the invention of the optical telescope, instruments for other wavelengths, neutrino detectors, or gravitational wave observatories. It would be a tragedy to miss the opportunity to fully characterize the next one. To aid preparations for its observations, we model the distance, extinction, and magnitude probability distributions of a successful Galactic core-collapse supernova (ccSN), its shock breakout radiation, and its massive star progenitor. We find, at very high probability (sime 100%), that the next Galactic SN will easily be detectable in the near-IR and that near-IR photometry of the progenitor star very likely (sime 92%) already exists in the Two Micron All Sky Survey. Most ccSNe (98%) will be easily observed in the optical, but a significant fraction (43%) will lack observations of the progenitor due to a combination of survey sensitivity and confusion. If neutrino detection experiments can quickly disseminate a likely position (~3°), we show that a modestly priced IR camera system can probably detect the shock breakout radiation pulse even in daytime (64% for the cheapest design). Neutrino experiments should seriously consider adding such systems, both for their scientific return and as an added and internal layer of protection against false triggers. We find that shock breakouts from failed ccSNe of red supergiants may be more observable than those of successful SNe due to their lower radiation temperatures. We review the process by which neutrinos from a Galactic ccSN would be detected and announced. We provide new information on the EGADS system and its potential for providing instant neutrino alerts. We also discuss the distance, extinction, and magnitude probability distributions for the next Galactic Type Ia supernova (SN Ia). Based on our modeled observability, we find a Galactic ccSN rate of 3.2^{+7.3}_{-2.6} per century and a Galactic SN Ia rate of 1.4^{+1.4}_{-0.8} per century for a

  9. An Approach to Peabody's Gifts and Legacies.

    Science.gov (United States)

    Parker, Franklin

    1994-01-01

    One in a collection of papers on self-made millionaire and educational philanthropist George Peabody offers a listing of his gifts and legacies, which fall into the categories of libraries, lyceums, athenaeum, art, music; science; model housing; education; exploration; patriotic causes; historical societies; hospitals; churches; legacies; and…

  10. Types and concept analysis for legacy systems

    NARCIS (Netherlands)

    T. Kuipers (Tobias); L.M.F. Moonen (Leon)

    2000-01-01

    textabstractWe combine type inference and concept analysis in order to gain insight into legacy software systems. Type inference for Cobol yields the types for variables and program parameters. These types are used to perform mathematical concept analysis on legacy systems. We have developed

  11. Northeastern Area Forest Legacy Program Yearbook 2008

    Science.gov (United States)

    US Forest Service, Northeastern Area, State and Private Forestry

    2009-01-01

    The purpose of the Forest Legacy Program (FLP) is to protect environmentally important forest areas that are threatened by conversion to nonforest uses. The Forest Legacy Program is a partnership between participating States and the Forest Service, U.S. Department of Agriculture. These two entities work together to identify important forest lands and...

  12. A validatable legacy database migration using ORM

    NARCIS (Netherlands)

    Moes, T.H.; Wijbenga, J.P.; Balsters, H.; Huitema, G.B.

    2012-01-01

    This paper describes a method used in a real-life case of a legacy database migration. The difficulty of the case lies in the fact that the legacy application to be replaced has to remain fully available during the migration process while at the same time data from the old system is to be integrated

  13. DUST IN ACTIVE GALACTIC NUCLEI: ANOMALOUS SILICATE TO OPTICAL EXTINCTION RATIOS?

    Energy Technology Data Exchange (ETDEWEB)

    Lyu, Jianwei; Hao, Lei [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Li, Aigen, E-mail: haol@shao.ac.cn [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States)

    2014-09-01

    Dust plays a central role in the unification theory of active galactic nuclei (AGNs). However, little is known about the nature (e.g., size, composition) of the dust that forms a torus around the AGN. In this Letter, we report a systematic exploration of the optical extinction (A{sub V} ) and the silicate absorption optical depth (Δτ{sub 9.7}) of 110 type 2 AGNs. We derive A{sub V} from the Balmer decrement based on the Sloan Digital Sky Survey data, and Δτ{sub 9.7} from the Spitzer/InfraRed Spectrograph data. We find that with a mean ratio of (A{sub V} /Δτ{sub 9.7}) ≲ 5.5, the optical-to-silicate extinction ratios of these AGNs are substantially lower than that of the Galactic diffuse interstellar medium (ISM) for which A{sub V} /Δτ{sub 9.7} ≈ 18.5. We argue that the anomalously low A{sub V} /Δτ{sub 9.7} ratio could be due to the predominance of larger grains in the AGN torus compared to that in the Galactic diffuse ISM.

  14. Implications of the Diffuse Galactic Continuum

    National Research Council Canada - National Science Library

    Skibo, J. G; Ramaty, R; Purcell, W. R

    1996-01-01

    .... This exceeds by an order of magnitude the total power provided by Galactic supernovae. We suggest that this power might be derived form the gravitational potential released on the passage of the ISM through Galactic spiral arm compressions...

  15. VizieR Online Data Catalog: Spitzer photometric time series of HD 97658 (Van Grootel+, 2014)

    Science.gov (United States)

    Van Grootel, V.; Gillon, M.; Valencia, D.; Madhusudhan, N.; Dragomir, D.; Howe, A. R.; Burrows, A. S.; Demory, B.-O.; Deming, D.; Ehrenreich, D.; Lovis, C.; Mayor, M.; Pepe, F.; Queloz, D.; Scuflaire, R.; Seager, S.; Segransan, D.; Udry, S.

    2017-07-01

    We monitored HD 97658 with Spitzer's IRAC camera on 2013 August 10 from 13:01:00 to 18:27:00 UT, corresponding to a transit window as computed from the MOST transit ephemeris (Dragomir et al. 2013, J/ApJ/772/L2). These Spitzer data were acquired in the context of the Cycle 9 program 90072 (PI: M. Gillon) dedicated to the search for the transits of RV-detected low-mass planets. They consist of 2320 sets of 64 individual subarray images obtained at 4.5 μm with an integration time of 0.08 s. They are available on the Spitzer Heritage Archive database under the form of 2320 Basic Calibrated Data files calibrated by the standard Spitzer reduction pipeline (version S19.1.0). (1 data file).

  16. Utrecht and Galactic Radio Astronomy

    NARCIS (Netherlands)

    van Woerden, H.

    Important roles in early Dutch Galactic radio astronomy were played by several Utrecht astronomers: Van de Hulst, Minnaert and Houtgast. The poster announcing the conference contained a number of pictures referring to scientific achievements of the Astronomical Institute Utrecht. One of these

  17. Abundances in the Galactic bulge

    Energy Technology Data Exchange (ETDEWEB)

    Barbuy, B; Alves-Brito, A [Universidade de Sao Paulo, IAG, Rua do Matao 1226, Sao Paulo 05508-900 (Brazil); Ortolani, S; Zoccali, M [Dipartimento di Astronomia, Universita di Padova, Vicolo dell' Osservatorio 2, I-35122 Padova (Italy); Hill, V; Gomez, A [Observatoire de Paris-Meudon, 92195 Meudon Cedex (France); Melendez, J [Centro de AstrofIsica da Universidade de Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Asplund, M [Max Planck Institute for Astrophysics, Postfach 1317, 85741 Garching (Germany); Bica, E [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, CP 15051, Porto Alegre 91501-970 (Brazil); Renzini, A [Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Minniti, D [Department of Astronomy and Astrophysics, Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)], E-mail: barbuy@astro.iag.usp.br

    2008-12-15

    The metallicity distribution and abundance ratios of the Galactic bulge are reviewed. Issues raised by recent work of different groups, in particular the high metallicity end, the overabundance of {alpha}-elements in the bulge relative to the thick disc and the measurement of giants versus dwarfs, are discussed. Abundances in the old moderately metal-poor bulge globular clusters are described.

  18. Mapping Dust in 3D with DECam: A Pilot Galactic Plane Survey

    Science.gov (United States)

    Finkbeiner, Douglas P.; Schlafly, Edward F.; Burke, David L.; Bechtol, Keith; Kelly, Patrick

    2014-02-01

    We propose to survey the southern Galactic plane in order to determine the three-dimensional distribution of stars, gas, and especially dust in the Milky Way. While the total column of dust through the Galaxy can be estimated by emission-based methods (e.g. Schlegel, Finkbeiner and Davis 1998), the 3D distribution of dust must be determined by measurements of the reddening and distance to stars embedded in the dust. We propose a 3-dither strategy with sufficient exposure to see main-sequence turnoff stars at 10 kpc through a dust column of E(B - V)=1.5 mag. Our preliminary study with PanSTARRS-1 demonstrates that grizy photometry is satisfactory to create accurate three-dimensional dust maps in the Galactic plane. The proposed survey would extend these maps over area inaccessible from the north, and go deeper than PanSTARRS. Moreover, the survey would be a valuable legacy data set for studies of Galactic structure and stellar populations, providing, together with PanSTARRS-1, five-band imaging of the entire Galactic plane. The survey is a pilot project for an eventual survey of a larger part of the (delta) < -30 sky.

  19. The legacy of fossil fuels.

    Science.gov (United States)

    Armaroli, Nicola; Balzani, Vincenzo

    2011-03-01

    Currently, over 80% of the energy used by mankind comes from fossil fuels. Harnessing coal, oil and gas, the energy resources contained in the store of our spaceship, Earth, has prompted a dramatic expansion in energy use and a substantial improvement in the quality of life of billions of individuals in some regions of the world. Powering our civilization with fossil fuels has been very convenient, but now we know that it entails severe consequences. We treat fossil fuels as a resource that anyone anywhere can extract and use in any fashion, and Earth's atmosphere, soil and oceans as a dump for their waste products, including more than 30 Gt/y of carbon dioxide. At present, environmental legacy rather than consistence of exploitable reserves, is the most dramatic problem posed by the relentless increase of fossil fuel global demand. Harmful effects on the environment and human health, usually not incorporated into the pricing of fossil fuels, include immediate and short-term impacts related to their discovery, extraction, transportation, distribution, and burning as well as climate change that are spread over time to future generations or over space to the entire planet. In this essay, several aspects of the fossil fuel legacy are discussed, such as alteration of the carbon cycle, carbon dioxide rise and its measurement, greenhouse effect, anthropogenic climate change, air pollution and human health, geoengineering proposals, land and water degradation, economic problems, indirect effects on the society, and the urgent need of regulatory efforts and related actions to promote a gradual transition out of the fossil fuel era. While manufacturing sustainable solar fuels appears to be a longer-time perspective, alternatives energy sources already exist that have the potential to replace fossil fuels as feedstocks for electricity production. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Exploring the Dust Content of Galactic Winds with Herschel. II. Nearby Dwarf Galaxies*

    Science.gov (United States)

    McCormick, Alexander; Veilleux, Sylvain; Meléndez, Marcio; Martin, Crystal L.; Bland-Hawthorn, Joss; Cecil, Gerald; Heitsch, Fabian; Müller, Thomas; Rupke, David S. N.; Engelbracht, Chad

    2018-03-01

    We present results from analysis of deep Herschel Space Observatory observations of six nearby dwarf galaxies known to host galactic-scale winds. The superior far-infrared sensitivity and angular resolution of Herschel have allowed detection of cold circumgalactic dust features beyond the stellar components of the host galaxies traced by Spitzer 4.5 μm images. Comparisons of these cold dust features with ancillary data reveal an imperfect spatial correlation with the ionized gas and warm dust wind components. We find that typically ˜10-20% of the total dust mass in these galaxies resides outside of their stellar disks, but this fraction reaches ˜60% in the case of NGC 1569. This galaxy also has the largest metallicity (O/H) deficit in our sample for its stellar mass. Overall, the small number of objects in our sample precludes drawing strong conclusions on the origin of the circumgalactic dust. We detect no statistically significant trends with star formation properties of the host galaxies, as might be expected if the dust were lifted above the disk by energy inputs from on-going star formation activity. Although a case for dust entrained in a galactic wind is seen in NGC 1569, in all cases, we cannot rule out the possibility that some of the circumgalactic dust might be associated instead with gas accreted or removed from the disk by recent galaxy interaction events, or that it is part of the outer gas-rich portion of the disk that lies below the sensitivity limit of the Spitzer 4.5 μm data.

  1. Reanalysis of galactic primary nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Twarog, B.A.; Wheeler, J.C.

    1987-05-01

    Primary nucleosynthesis in the Galactic disk is reexamined in light of improved observational data for Mg in field stars and improved theoretical data in the form of stellar elemental yields and a higher C-12(alpha, gamma)O-16 reaction rate. It is concluded that the data for O, C, Fe, and Mg are consistent with a constant relative production rate for these elements over the lifetime of the disk in a standard infall model. The yield distribution is nonsolar. Additionally, any continuous mass function in which all stars over 12 solar masses explode both fails to meet the observational constraints on elemental production ratios and overproduces significant amounts of O for the most plausible mass function. Consideration of the probable uncertainties indicates that the discrepancy is real and casts doubt on the capability of current stellar nucleosynthesis theory to provide reliable constraints on stellar evolution, the history of the mass function, or models of galactic chemical evolution. 32 references.

  2. Kinematics of galactic planetary nebulae

    International Nuclear Information System (INIS)

    Kiosa, M.I.; Khromov, G.S.

    1979-01-01

    The classical method of determining the components of the solar motion relative to the centroid of the system of planetary nebulae with known radial velocities is investigated. It is shown that this method is insensitive to random errors in the radial velocities and that low accuracy in determining the coordinates of the solar apex and motion results from the insufficient number of planetaries with measured radial velocities. The planetary nebulae are found not to satisfy well the law of differential galactic rotation with circular orbits. This is attributed to the elongation of their galactic orbits. A method for obtaining the statistical parallax of planetary nebulae is considered, and the parallax calculated from the tau components of their proper motion is shown to be the most reliable

  3. Spitzer Observations of Massive, Red Galaxies at High Redshift

    Science.gov (United States)

    Papovich, C.; Moustakas, L. A.; Dickinson, M.; Le Floc'h, E.; Rieke, G. H.; Daddi, E.; Alexander, D. M.; Bauer, F.; Brandt, W. N.; Dahlen, T.; Egami, E.; Eisenhardt, P.; Elbaz, D.; Ferguson, H. C.; Giavalisco, M.; Lucas, R. A.; Mobasher, B.; Pérez-González, P. G.; Stutz, A.; Rieke, M. J.; Yan, H.

    2006-03-01

    We study massive galaxies at z~1-3.5 using HST optical imaging, ground-based near-IR imaging, and Spitzer observations at 3-24 μm. From Ks-selected galaxies in the ~=130 arcmin2 GOODS-S field, we identify 153 distant red galaxies (DRGs) with (J-Ks)Vega>=2.3. This sample is approximately complete in stellar mass for passively evolving galaxies above 1011 Msolar and z~4-6 mag) starbursts (at zmed~1.7). Very few DRGs (=1011 Msolar have specific star formation rates (SFRs per unit mass) including the reradiated far-IR emission that range from 0.2 to 10 Gyr-1. Based on the X-ray luminosities and rest-frame near-IR colors, roughly one-quarter of the DRGs contain AGNs, implying that the growth of supermassive black holes coincides with the formation of massive galaxies. At 1.5=1011 Msolar have an integrated specific SFR comparable to the global value of all galaxies. In contrast, galaxies at z~0.3-0.75 with M>=1011 Msolar have an integrated specific SFR less than the global value and more than an order of magnitude lower than that for massive DRGs. At zcontract 1407; on observations taken with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555 and on observations collected at the Kitt Peak National Observatory (KPNO), National Optical Astronomical Observatory (NOAO), which is operated by AURA, Inc., under cooperative agreement with the National Science Foundation. Observations have also been carried out using the Very Large Telescope at the ESO Paranal Observatory under program ID LP168.A-0485.

  4. FAR-INFRARED PROPERTIES OF SPITZER-SELECTED LUMINOUS STARBURSTS

    International Nuclear Information System (INIS)

    Kovacs, A.; Omont, A.; Fiolet, N.; Beelen, A.; Dole, H.; Lagache, G.; Lonsdale, C.; Polletta, M.; Greve, T. R.; Borys, C.; Dowell, C. D.; Bell, T. A.; Cox, P.; De Breuck, C.; Farrah, D.; Menten, K. M.; Owen, F.

    2010-01-01

    We present SHARC-2 350 μm data on 20 luminous z ∼ 2 starbursts with S 1.2 m m > 2 mJy from the Spitzer-selected samples of Lonsdale et al. and Fiolet et al. All the sources were detected, with S 350 μ m > 25 mJy for 18 of them. With the data, we determine precise dust temperatures and luminosities for these galaxies using both single-temperature fits and models with power-law mass-temperature distributions. We derive appropriate formulae to use when optical depths are non-negligible. Our models provide an excellent fit to the 6 μm-2 mm measurements of local starbursts. We find characteristic single-component temperatures T 1 ≅ 35.5 ± 2.2 K and integrated infrared (IR) luminosities around 10 12.9±0.1 L sun for the SWIRE-selected sources. Molecular gas masses are estimated at ≅4 x 10 10 M sun , assuming κ 850 μ m = 0.15 m 2 kg -1 and a submillimeter-selected galaxy (SMG)-like gas-to-dust mass ratio. The best-fit models imply ∼>2 kpc emission scales. We also note a tight correlation between rest-frame 1.4 GHz radio and IR luminosities confirming star formation as the predominant power source. The far-IR properties of our sample are indistinguishable from the purely submillimeter-selected populations from current surveys. We therefore conclude that our original selection criteria, based on mid-IR colors and 24 μm flux densities, provides an effective means for the study of SMGs at z ∼ 1.5-2.5.

  5. NEOs in the mid-infrared: from Spitzer to JWST

    Science.gov (United States)

    Mueller, Michael; Thomas, Cristina A.

    2016-10-01

    Near-Earth Objects (NEOs) account for a surprisingly large fraction of the Spitzer observing time devoted to Solar System science. As a community, we should think of ways to repeat that success with JWST. JWST is planning an open Early Release Science Program, with the expected deadline for letters of intent in early 2017. We can't wait for next year's DPS to develop ideas. The time is now!In order to stir up the discussion, we will present ideas for NEO observing programs that are well adapted to JWST's capabilities and limitations, based on our recent PASP paper (Thomas et al., 2016). Obvious measurement objectives would include* size and albedo from thermal continuum (MIRI photometry)* thermal inertia for objects with well-known shape and spin state (MIRI)* taxonomy through reflection spectroscopy and emission spectroscopy in the NIR and MIR; NIR colors for faint objects.In all cases, JWST's sensitivity will allow us to go deeper than currently possible by at least an order of magnitude. Meter-sized NEOs similar to 2009 BD or 2011 MD are easy targets for MIRI spectrophotometry!The following limitations must be kept in mind, however: JWST's large size makes it slow to move. Most problematic for NEOs is probably the resulting 'speed limit': non-sidereal tracking is supported up to a rate of 30 mas/s, NEOs can easily move faster than that (ways to relax this constraint are under discussion). The average slew to a new target is budgeted to take 30 min, effectively ruling out programs many-target programs like ExploreNEOs or NEOSurvey (see D. Trilling's paper). Additionally, JWST will only observe close to quadrature, translating to large solar phase angles for NEO observations; this is familiar from other space-based IR facilities.

  6. Galactic Structures from Gravitational Radii

    Directory of Open Access Journals (Sweden)

    Salvatore Capozziello

    2018-02-01

    Full Text Available We demonstrate that the existence of a Noether symmetry in f ( R theories of gravity gives rise to an additional gravitational radius, besides the standard Schwarzschild one, determining the dynamics at galactic scales. By this feature, it is possible to explain the baryonic Tully-Fisher relation and the rotation curve of gas-rich galaxies without the dark matter hypothesis. Furthermore, under the same standard, the Fundamental Plane of elliptical galaxies can be addressed.

  7. Millimetre Astronomy Legacy Team 90 GHz Survey (MALT 90)

    Science.gov (United States)

    Jackson, James; Lo, Nadia; Rathborne, Jill; Jones, Paul; Muller, Erik; Cunningham, Maria; Brooks, Kate; Fuller, Gary; Barnes, Peter; Menten, Karl; Schilke, Peter; Garay, Guido; Mardones, Diego; Minier, Vincent; Longmore, Steven; Wyrowski, Friedrich; Herpin, Fabrice; Hill, Tracey; Bronfman, Leonardo; Deharveng, Lise; Schuller, Frederic; Motte, Frédérique; Peretto, Nicolas; Bontemps, Sylvain; Wienen, Marion; Contreras, Yanett; Lenfestey, Clare; Foster, Jonathan; Sanhueza, Patricio; Claysmith, Christopher; Hoq, Sadia

    2012-04-01

    We request Mopra time to complete MALT90, a large, volume-complete survey of high-mass star-forming cores. MALT90 is unique and exploits Mopra's capability for OTF mapping and simultaneous imaging of 16 molecular lines near 90GHz. These molecular lines probe the cores' physical, chemical, and evolutionary state. The target cores are selected from the 870um ATLASGAL survey to host the early stages of high-mass star formation and to span their complete range in evolution. Each core will be mapped at excellent angular (40'') and spectral (0.1km/s) resolution. As in the previous years, fully reduced data products will be made available to the community through the ATOA. In order for MALT90 to be volume-complete, we require 1397 hours to map 942 remaining cores. This time allocation is necessary so that MALT90 is complete to all high-mass cores out to 7kpc: a carefully chosen distance limit to adequate sample a range of Galactic environments and to include all high-mass regions for which individual cores can be resolved with ALMA. When complete, MALT90 will provide an important legacy database for the community and supply the definitive source list of high-mass cores for ALMA.

  8. NEW MEASUREMENTS OF THE COSMIC INFRARED BACKGROUND FLUCTUATIONS IN DEEP SPITZER/IRAC SURVEY DATA AND THEIR COSMOLOGICAL IMPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kashlinsky, A. [SSAI, Lanham MD 20706 (United States); Arendt, R. G.; Mather, J.; Moseley, S. H. [Observational Cosmology Laboratory, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ashby, M. L. N.; Fazio, G. G., E-mail: alexander.kashlinsky@nasa.gov [Center for Astrophysics, Cambridge, MA 02138 (United States)

    2012-07-01

    We extend previous measurements of cosmic infrared background (CIB) fluctuations to {approx}< 1 Degree-Sign using new data from the Spitzer Extended Deep Survey. Two fields with depths of {approx_equal} 12 hr pixel{sup -1} over three epochs are analyzed at 3.6 and 4.5 {mu}m. Maps of the fields were assembled using a self-calibration method uniquely suitable for probing faint diffuse backgrounds. Resolved sources were removed from the maps to a magnitude limit of mag{sub AB} {approx_equal} 25, as indicated by the level of the remaining shot noise. The maps were then Fourier transformed and their power spectra were evaluated. Instrumental noise was estimated from the time-differenced data, and subtracting this isolates the spatial fluctuations of the actual sky. The power spectra of the source-subtracted fields remain identical (within the observational uncertainties) for the three epochs indicating that zodiacal light contributes negligibly to the fluctuations. Comparing to 8 {mu}m power spectra shows that Galactic cirrus cannot account for the fluctuations. The signal appears isotropically distributed on the sky as required for an extragalactic origin. The CIB fluctuations continue to diverge to >10 times those of known galaxy populations on angular scales out to {approx}< 1 Degree-Sign . The low shot-noise levels remaining in the diffuse maps indicate that the large-scale fluctuations arise from the spatial clustering of faint sources well below the confusion noise. The spatial spectrum of these fluctuations is in reasonable agreement with an origin in populations clustered according to the standard cosmological model ({Lambda}CDM) at epochs coinciding with the first stars era.

  9. The physics of galactic winds driven by active galactic nuclei

    Science.gov (United States)

    Faucher-Giguère, Claude-André; Quataert, Eliot

    2012-09-01

    Active galactic nuclei (AGN) drive fast winds in the interstellar medium of their host galaxies. It is commonly assumed that the high ambient densities and intense radiation fields in galactic nuclei imply short cooling times, thus making the outflows momentum conserving. We show that cooling of high-velocity shocked winds in AGN is in fact inefficient in a wide range of circumstances, including conditions relevant to ultraluminous infrared galaxies (ULIRGs), resulting in energy-conserving outflows. We further show that fast energy-conserving outflows can tolerate a large amount of mixing with cooler gas before radiative losses become important. For winds with initial velocity vin ≳ 10 000 km s-1, as observed in ultraviolet and X-ray absorption, the shocked wind develops a two-temperature structure. While most of the thermal pressure support is provided by the protons, the cooling processes operate directly only on the electrons. This significantly slows down inverse Compton cooling, while free-free cooling is negligible. Slower winds with vin ˜ 1000 km s-1, such as may be driven by radiation pressure on dust, can also experience energy-conserving phases but under more restrictive conditions. During the energy-conserving phase, the momentum flux of an outflow is boosted by a factor ˜vin/2vs by work done by the hot post-shock gas, where vs is the velocity of the swept-up material. Energy-conserving outflows driven by fast AGN winds (vin ˜ 0.1c) may therefore explain the momentum fluxes Ṗ≫LAGN/c of galaxy-scale outflows recently measured in luminous quasars and ULIRGs. Shocked wind bubbles expanding normal to galactic discs may also explain the large-scale bipolar structures observed in some systems, including around the Galactic Centre, and can produce significant radio, X-ray and γ-ray emission. The analytic solutions presented here will inform implementations of AGN feedback in numerical simulations, which typically do not include all the important

  10. Assisted Emulation for Legacy Executables

    Directory of Open Access Journals (Sweden)

    Kam Woods

    2010-07-01

    Full Text Available Emulation is frequently discussed as a failsafe preservation strategy for born-digital documents that depend on contemporaneous software for access (Rothenberg, 2000. Yet little has been written about the contextual knowledge required to successfully use such software. The approach we advocate is to preserve necessary contextual information through scripts designed to control the legacy environment, and created during the preservation workflow. We describe software designed to minimize dependence on this knowledge by offering automated configuration and execution of emulated environments. We demonstrate that even simple scripts can reduce impediments to casual use of the digital objects being preserved. We describe tools to automate the remote use of preserved objects on local emulation environments.  This can help eliminate both a dependence on physical reference workstations at preservation institutions, and provide users accessing materials over the web with simplified, easy-to-use environments. Our implementation is applied to examples from an existing collection of over 4,000 virtual CD-ROM images containing thousands of custom binary executables.

  11. Structure and content of the galaxy and galactic gamma rays

    International Nuclear Information System (INIS)

    1976-01-01

    The conference included papers on γ-ray pulsars, galactic diffuse flux and surveys, radio surveys of external galaxies, galactic distribution of pulsars, and galactic gamma emission. Galactic structure drawing on all branches of galactic astronomy is discussed. New and unpublished material is included

  12. Structure and content of the galaxy and galactic gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    The conference included papers on ..gamma..-ray pulsars, galactic diffuse flux and surveys, radio surveys of external galaxies, galactic distribution of pulsars, and galactic gamma emission. Galactic structure drawing on all branches of galactic astronomy is discussed. New and unpublished material is included. (JFP)

  13. Parallel MOPEX: Computing Mosaics of Large-Area Spitzer Surveys on a Cluster Computer

    Directory of Open Access Journals (Sweden)

    Joseph C. Jacob

    2007-01-01

    Full Text Available The Spitzer Science Center's MOPEX software is a part of the Spitzer Space Telescope's operational pipeline that enables detection of cosmic ray collisions with the detector array, masking of the corrupted pixels due to these collisions, subsequent mosaicking of image fields, and extraction of point sources to create catalogs of celestial objects. This paper reports on our experiences in parallelizing the parts of MOPEX related to cosmic ray rejection and mosaicking on a 1,024-processor cluster computer at NASA's Jet Propulsion Laboratory. The architecture and performance of the new Parallel MOPEX software are described. This work was done in order to rapidly mosaic the IRAC shallow survey data, covering a region of the sky observed with one of Spitzer's infrared instruments for the study of galaxy clusters, large-scale structure, and brown dwarfs.

  14. The Role of Environment on Active Galactic Nuclei Triggering

    Science.gov (United States)

    Mo, Wenli; MaDCoWS Collaboration

    2018-01-01

    Active galactic nuclei (AGN) play a role in regulating galactic star formation and transitioning a galaxy from star forming to passive. However, the mechanisms triggering AGN are still debated and can depend on both environmental and secular processes. The dense, rich environment of galaxy clusters provides a unique regime in which to study the impact of large-scale environmental factors on AGN triggering. We present analysis of AGN in 2300 galaxy clusters from the Massive and Distant Clusters of WISE Survey (MaDCoWS) at redshift z~1. With MaDCoWS, we significantly improve the statistical precision of cluster AGN studies during an epoch of major assembly of the cluster and intracluster medium. We use literature catalogs of AGN selected via optical+infrared (OIR), mid-infrared (MIR), and radio data to isolate populations of majority unobscured, dust-obscured, and radio-loud AGN, respectively, and crossmatch with Spitzer images of MaDCoWS clusters. The fraction of cluster galaxies that host OIR- and MIR-selected AGN is comparable to that of the field at all cluster radii. We find no statistically significant dependence of the OIR- and MIR-selected AGN fraction upon cluster mass, implying that environment is at most a second order factor for OIR and MIR AGN triggering. In contrast, the radio-selected AGN fraction is ~2 times that of the field in cluster cores. While the total overdensity of radio-selected AGN increases with cluster mass, we also find that the fraction of cluster galaxies hosting radio-selected AGN is greatest in low mass clusters. Our results are consistent with a picture in which environmental factors do play a role in influencing the fueling of radio-mode AGN. We also conduct a study of radio sources in MaDCoWS clusters to investigate the properties of these radio sources and how they impact their surrounding environment. We find that clusters with central radio source have more central OIR- and MIR-selected AGN than radio-inactive clusters

  15. Legacy material work-off project

    International Nuclear Information System (INIS)

    Sloan, T.J.; Baker, D.H. IV

    1999-01-01

    Los Alamos National Laboratory (LANL) and its subcontractors recently completed a nine-month legacy material clean-up effort. Legacy materials were defined as chemicals, hazardous, non-hazardous, and both hazardous and radioactive (mixed), that no longer served a programmatic use and had no identified individual owner within the Laboratory. Once personnel identified the legacy materials, the items were transferred to Solid Waste Operation's (EM-SWO) control. Upon completing this process, the responsible division-level manager was required to certify that all non-radioactive hazardous and non-hazardous materials and acceptable mixed legacy materials had been identified and transferred to EM-SWO for proper handling or disposal. The major expense in this project was the cost of actual chemical and radiological analysis. This expense was the result of items not having an identified individual owner. The major benefit of this project is that LANL is now in an excellent position to implement its Integrated Safety Management (ISM) Plan, which requires the implementation of safe work practices, including requirements for removing unused items when vacating workspaces. Effective implementation of ISM will go a long way toward ensuring that legacy materials are no longer an issue at the Laboratory

  16. The Spitzer survey of interstellar clouds in the gould belt. VI. The Auriga-California molecular cloud observed with IRAC and MIPS

    Energy Technology Data Exchange (ETDEWEB)

    Broekhoven-Fiene, Hannah; Matthews, Brenda C. [Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8W 3P6 (Canada); Harvey, Paul M. [Astronomy Department, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Gutermuth, Robert A. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Huard, Tracy L.; Miller, Jennifer F. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Tothill, Nicholas F. H. [School of Computing, Engineering and Mathematics, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751 (Australia); Nutter, David [School of Physics and Astronomy, Cardiff University, Queen' s Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); DiFrancesco, James [National Research Council Herzberg Astronomy and Astrophysics, Victoria, BC, V9E 2E7 (Canada); Jørgensen, Jes K. [Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-DK-2100 Copenhagen Ø. (Denmark); Allen, Lori E. [National Optical Astronomy Observatories, Tucson, AZ (United States); Chapman, Nicholas L. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Dunham, Michael M. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Merín, Bruno [Herschel Science Centre, ESAC-ESA, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Terebey, Susan [Department of Physics and Astronomy PS315, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Peterson, Dawn E. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); and others

    2014-05-01

    We present observations of the Auriga-California Molecular Cloud (AMC) at 3.6, 4.5, 5.8, 8.0, 24, 70, and 160 μm observed with the IRAC and MIPS detectors as part of the Spitzer Gould Belt Legacy Survey. The total mapped areas are 2.5 deg{sup 2} with IRAC and 10.47 deg{sup 2} with MIPS. This giant molecular cloud is one of two in the nearby Gould Belt of star-forming regions, the other being the Orion A Molecular Cloud (OMC). We compare source counts, colors, and magnitudes in our observed region to a subset of the SWIRE data that was processed through our pipeline. Using color-magnitude and color-color diagrams, we find evidence for a substantial population of 166 young stellar objects (YSOs) in the cloud, many of which were previously unknown. Most of this population is concentrated around the LkHα 101 cluster and the filament extending from it. We present a quantitative description of the degree of clustering and discuss the relative fraction of YSOs in earlier (Class I and F) and later (Class II) classes compared to other clouds. We perform simple SED modeling of the YSOs with disks to compare the mid-IR properties to disks in other clouds and identify 14 classical transition disk candidates. Although the AMC is similar in mass, size, and distance to the OMC, it is forming about 15-20 times fewer stars.

  17. The Spitzer Survey of Interstellar Clouds in the Gould Belt. VI. The Auriga-California Molecular Cloud Observed with IRAC and MIPS

    Science.gov (United States)

    Broekhoven-Fiene, Hannah; Matthews, Brenda C.; Harvey, Paul M.; Gutermuth, Robert A.; Huard, Tracy L.; Tothill, Nicholas F. H.; Nutter, David; Bourke, Tyler L.; DiFrancesco, James; Jorgensen, Jes K.; hide

    2014-01-01

    We present observations of the Auriga-California Molecular Cloud (AMC) at 3.6, 4.5, 5.8, 8.0, 24, 70 and 160 micrometers observed with the IRAC and MIPS detectors as part of the Spitzer Gould Belt Legacy Survey. The total mapped areas are 2.5 deg(exp 2) with IRAC and 10.47 deg2 with MIPS. This giant molecular cloud is one of two in the nearby Gould Belt of star-forming regions, the other being the Orion A Molecular Cloud (OMC). We compare source counts, colors and magnitudes in our observed region to a subset of the SWIRE data that was processed through our pipeline. Using color-magnitude and color-color diagrams, we find evidence for a substantial population of 166 young stellar objects (YSOs) in the cloud, many of which were previously unknown. Most of this population is concentrated around the LkH(alpha) 101 cluster and the filament extending from it. We present a quantitative description of the degree of clustering and discuss the fraction of YSOs in the region with disks relative to an estimate of the diskless YSO population. Although the AMC is similar in mass, size and distance to the OMC, it is forming about 15 - 20 times fewer stars.

  18. Galactic Diffuse Polarized Emission Ettore Carretti

    Indian Academy of Sciences (India)

    to decouple from the spiral arms taking a ring-like shape. The big picture is thus starting to take shape, but essential points are still under debate, like number and position of reversals or the field pattern in the outer galaxy. The situation in the galactic halo is far less clear, essentially because of lack of data at high galactic ...

  19. A synoptic view of galactic processes

    Science.gov (United States)

    Stecker, F. W.

    1981-01-01

    The power of using synoptic galactic surveys in many wavelength bands in order to obtain a more complete picture and a better understanding of the dynamics of the interstellar medium and to study galactic structure and evolution on a large scale is discussed. The implications of the picture presented by mm wave CO, far infrared and X ray surveys of the Galaxy are emphasized.

  20. Dust properties in the Galactic bulge

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.

    Context. It has been suggested that the ratio of total-to-selective extinction R-V in dust in the interstellar medium differs in the Galactic bulge from its value in the local neighborhood. Aims. We attempt to test this suggestion. Methods. The mid-infrared hydrogen lines in 16 Galactic bulge PNe

  1. Very High Energy -rays from Galactic Sources

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The field of Very High Energy (VHE) gamma ray astronomy using the Atmospheric Cerenkov Technique has entered an interesting phase with detection of various galactic and extragalactic sources. Among galactic sources, only the Crab nebula has been established as a standard candle.

  2. Age and leadership : The moderating role of legacy beliefs

    NARCIS (Netherlands)

    Zacher, Hannes; Rosing, Kathrin; Frese, Michael

    Age and age-related motivations have been neglected in leadership research. This study examined the moderating influence of legacy beliefs on the relationships between age and transformational, transactional, and passive-avoidant leadership behaviors. Legacy beliefs involve individuals' convictions

  3. Physical Properties of Asteroid (10302) 1989 ML, a Potential Spacecraft Target, from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Harris, A. W.

    2006-01-01

    We report on results from recent Spitzer observations of near-Earth asteroid (10302) 1989 ML, which is among the lowest-ranking objects in terms of the specific momentum Δv required to reach it from Earth. It was originally considered as a target for Hayabusa and is now under consideration as a

  4. The Accuracy of the Warm Spitzer Near-Earth Object Survey

    NARCIS (Netherlands)

    Harris, Alan W.; Mommert, M.; Hora, J. L.; Mueller, M.; Trilling, D. E.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Delbo', M.; Emery, J. P.; Fazio, G. G.; Mainzer, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2010-01-01

    We report on observations of near-Earth objects (NEOs) performed with IRAC as part of our on-going (2009-2011) Warm Spitzer NEO survey ("ExploreNEOs"), the primary aim of which is to provide sizes and albedos of some 700 NEOs. The emphasis of the work described here is an assessment of the overall

  5. Spitzer Observations of OGLE-2015-BLG-1212 Reveal a New Path toward Breaking Strong Microlens Degeneracies

    DEFF Research Database (Denmark)

    Bozza, V.; Shvartzvald, Y.; Udalski, A.

    2016-01-01

    Spitzer microlensing parallax observations of OGLE-2015-BLG-1212 decisively break a degeneracy between planetary and binary solutions that is somewhat ambiguous when only ground-based data are considered. Only eight viable models survive out of an initial set of 32 local minima in the parameter s...

  6. HST and Spitzer point source and dust lane detection in powerful narrow-line radio galaxies

    Science.gov (United States)

    Ramírez, E. A.; Tadhunter, C. N.; Dicken, D.; Rose, M.; Axon, D. J.; Sparks, W.

    2014-10-01

    We present the analysis of infrared HST and Spitzer data for a sample of 13 FRII powerful radio galaxies at 0.03 scale toroidal structure when this is viewed edge-on (Barthel 1989, Antonucci 1993). Our high resolution infrared observations provide new information about the optical extinction, orientation, and direct AGN detection of the inner kpc-scale region of the AGN.

  7. Random walks, Brownian motion, and interacting particle systems: a festschrift in honor of Frank Spitzer

    National Research Council Canada - National Science Library

    Durrett, Richard; Kesten, Harry; Spitzer, Frank

    1991-01-01

    ..., made the transparency used in the printing process. STUDENTS OF FRANK SPITZERSTUDENTS OF FRANK SPITZER 1957 J. W. Lamperti, On the asymptotic behavior of recurrent and almostrecurrent events. 1964 W. W. Whitman, Some strong laws for random walks and Brownian motion. 1965 J. C. Mineka, The existence and uniqueness of positive solutions to the Wien...

  8. Thermal properties of Trans-Neptunian objects and Centaurs from combined Herschel and Spitzer observations

    NARCIS (Netherlands)

    Santos-Sanz, P.; Lellouch, E.; Mommert, M.; Fornasier, S.; Stansberry, J.; Mueller, Th.; Kiss, C.; Vilenius, E.; Mueller, M.; Harris, A. W.; Delsanti, A.; Groussin, O.

    2012-01-01

    We present a study of the thermal properties of about 70 trans-Neptunian objects (TNOs) and Centaurs observed with Herschel Space Observatory [8] (either PACS or PACS and SPIRE) and Spitzer Space Telescope [12] (MIPS). We apply radiometric modeling techniques (NEATM [2]) to the measured fluxes to

  9. Thermal Properties Of Trans-neptunian Objects And Centaurs From Combined Herschel And Spitzer Observations

    NARCIS (Netherlands)

    Lellouch, Emmanuel; Santos-Sanz, P.; Mommert, M.; Fornasier, S.; Stansberry, J.; Müller, T.; Duffard, R.; Ortiz, J.; Kiss, C.; Vilenius, E.; Mueller, M.; Lacerda, P.; Harris, A.; TNOs are Cool Team, [No Value

    2012-01-01

    We present a study of the thermal properties of about 70 trans-Neptunian objects (TNOs) and Centaurs observed with Herschel Space Observatory (either PACS or PACS/SPIRE) and Spitzer (MIPS). The combined wavelength range is 24-160 μm and additionally up to 500 μm for a few targets. We apply

  10. Dust evolution in protoplanetary disks around Herbig Ae/Be stars—the Spitzer view

    NARCIS (Netherlands)

    Juhász, A.; Bouwman, J.; Henning, T.; Acke, B.; van den Ancker, M.E.; Meeus, G.; Dominik, C.; Min, M.; Tielens, A.G.G.M.; Waters, L.B.F.M.

    2010-01-01

    In this paper, we present mid-infrared spectra of a comprehensive set of Herbig Ae/Be stars observed with the Spitzer Space Telescope. The signal-to-noise ratio of these spectra is very high, ranging between about a hundred and several hundreds. During the analysis of these data we tested the

  11. Waters, dust evolution in protoplanetary disks around herbig ae/be stars—the spitzer view

    NARCIS (Netherlands)

    Juhász, A.; Bouwman, J.; Henning, Th.; Acke, B.; Van Den Ancker, M.; Meeus, G.; Dominik, C.; Min, M.|info:eu-repo/dai/nl/277318416; Tielens, A. G. G. M.; Waters, L.B.F.M.

    2010-01-01

    In this paper, we present mid-infrared spectra of a comprehensive set of Herbig Ae/Be stars observed with the Spitzer Space Telescope. The signal-to-noise ratio of these spectra is very high, ranging between about a hundred and several hundreds. During the analysis of these data we tested the

  12. Dust Evolution in Protoplanetary Disks Around Herbig Ae/Be Stars—the Spitzer View

    NARCIS (Netherlands)

    Juhasz, A.; Bouwman, J.; Henning, Th.; Acke, B.; van den Ancker, M. E.; Meeus, G.; Dominik, C.; Min, M.; Tielens, A. G. G. M.; Waters, L. B. F. M.

    2010-01-01

    In this paper, we present mid-infrared spectra of a comprehensive set of Herbig Ae/Be stars observed with the Spitzer Space Telescope. The signal-to-noise ratio of these spectra is very high, ranging between about a hundred and several hundreds. During the analysis of these data we tested the

  13. The Spitzer IRS infrared spectrum and abundances of the planetary nebula IC 2448

    NARCIS (Netherlands)

    Guiles, S.; Bernard-Salas, J.; Pottasch, S. R.; Roellig, T. L.

    2007-01-01

    We present the mid-infrared spectrum of the planetary nebula IC 2448. In order to determine the chemical composition of the nebula, we use the infrared line fluxes from the Spitzer spectrum along with optical line fluxes from the literature and ultraviolet line fluxes from archival IUE spectra. We

  14. Visible photometry of NEOs in support of a Warm Spitzer program

    Science.gov (United States)

    Trilling, David E.; Jones, Sarah; Penprase, Bryan; Emery, Josh; Harris, Alan; Spahr, Tim; Delbo, Marco

    2009-08-01

    Near Earth Objects (NEOs) may act as dynamical and compositional tracers of the history of near-Earth space. However, despite their scientific importance, key characteristics of the NEO population -- such as the size distribution, mix of albedos and mineralogies, and contributions from so-called dead or dormant comets -- remain largely unexplored; some 99% of all presently known NEOs are essentially uncharacterized. We have been awarded 500 hours of Warm Spitzer time to study some 700 NEOs. The Spitzer data will allow us to measure thermal fluxes and, in combination with optical data, derive albedos and diameters for a large fraction of all known NEOs. Remarkably, the primary uncertainty in our Spitzer results will derive from a lack of good optical photometry for our targets. Fortunately, our targets are generally bright, and obtaining good V band measurements of them requires only a modest amount of time on modest aperture telescopes. We propose here for 36 hours of SMARTS 1.3-m time or 54 hours of SMARTS 0.9-m time to obtain visible photometry of the 72 southern moderately bright ``B'' semester targets in our Warm Spitzer program. These program is ideal for queue/service observing because each observation requires only ~30 minutes and our targets are all over the sky.

  15. Bulk Densities of Binary Asteroids from the Warm Spitzer NEO Survey

    NARCIS (Netherlands)

    Kistler, John; Trilling, D. E.; Mueller, M.; Hora, J. L.; Harris, A. W.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Emery, J. P.; Fazo, G.; Mainzer, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2010-01-01

    The Warm Spitzer NEO survey, ExploreNEOs, will observe approximately 700 Near Earth Asteroids. Several of these objects are known to be binary asteroid systems. Binary systems are interesting due to the unique opportunity they present for determining the masses and densities of their constituent

  16. The radiation legacy of Russia

    International Nuclear Information System (INIS)

    Lebedev, V.A.

    2002-01-01

    Nuclear weapons making and testing, operation of enterprises of the nuclear industry, of military and civilian nuclear fleet, as well as peaceful nuclear explosions -- all that led in the USSR to release of radioactive products into the environment. In some parts of the FSU radioactive contamination exceeded permissible levels. The necessity of remediation of such territories became evident. The most part of the contamination resulted from major radiation accidents in Kyshtym (19570 and Chernobyl (1986). Today those objects, as well as some sites of radwaste storage and disposal, written-off nuclear submarines with non-unloaded spent nuclear fuel, some floating and on-shore repositories of nuclear fleet's radwaste and spent nuclear fuel, pose a potential hazard to the biosphere. Appropriate measures aimed at decreasing their impact on the population and environment are needed. Such measures should include both restoration of contaminated lands and social support programs for the population affected by radiation. The main task of the rehabilitation is reduction of consequences of internal and external exposure of the people, creation of necessary conditions for efficient and safe economical activities. Concrete objectives should be determined, as well as principles and standards to ensure radiation safety when conducting remediation works, and also -- specifications for evaluation of the lands condition prior to their remediation, criteria of decision making, rehabilitation planning, techniques of the lands' restoration and recommendations for their future uses. The Russian Federal special program 'Radioactive Waste and Spent Nuclear Materials Management, Utilization and Disposal for 1996-2005' envisages studies on Russia's radiation legacy's assessment on the basis of up-to-date information technologies of computer-based systems for data collection, storage and processing for accounting and analysis of information on availability, origin, physical and chemical

  17. Resolving Star Formation, Multiphase ISM Structure, and Wind Driving with MHD and RHD Models of Galactic Disks

    Science.gov (United States)

    Ostriker, Eve

    potentials and galactic rotation rates. Our simulations follow all thermal phases of the gas, the driving of turbulence, and the expulsion of material in high-velocity galactic winds as well as the circulation of lowervelocity material in galactic ``fountains.'' We resolve gravitational collapse and apply stellar population modeling to determine radiation emitted by star cluster particles, and both in situ and runaway O-star SN events. With time-dependent chemistry, we will be able to follow C+/C/CO transitions and assess the relationship between the observed molecular component and self-gravitating or diffuse clouds in varying galactic environments, also determining how cloud properties (e.g. distributions of mass, size, virial parameter, internal/external pressure, magnetization) and lifetimes depend on environment. We will also investigate the dependence on local galactic environment of: * mass and volume fractions, and turbulent and magnetic state, of each thermal and chemical ISM phase * star formation rate, and galactic wind mass loss rate in each ISM phase * metrics of ISM energy gain/loss, large-scale force balance, wind acceleration * roles of SN and radiation feedback in setting cloud SFEs, overall SFRs, and wind massloss rates Our models will be valuable for interpreting a wide range of observations with Chandra, Hubble, Spitzer, Herschel, Planck, and ground-based telescopes. Obtaining self-consistent solutions for the dynamical, thermal, magnetic, chemical, and radiative state of the star-forming ISM is a long-sought goal of galactic theory. Understanding why ISM and star formation properties vary among and within galaxies is essential for interpreting new multiwavelength extragalactic surveys. Connecting galactic winds to star formation via resolved physical mechanisms will provide a missing link in contemporary galaxy formation models. With our planned research program, we are in a position to achieve all of these advances.

  18. Spitzer Photometry of WISE-selected Brown Dwarf and Hyper-luminous Infrared Galaxy Candidates

    Science.gov (United States)

    Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; Donoso, Emilio; Jarrett, Thomas H.; Lonsdale, Carol; Mace, Gregory; Mainzer, A.; Marsh, Ken; Padgett, Deborah; Petty, Sara; Ressler, Michael E.; Skrutskie, Michael F.; Stanford, Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen; Yan, Lin

    2012-11-01

    We present Spitzer 3.6 and 4.5 μm photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 μm ~ 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (>20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of ~7.33 × 105 objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 μm photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

  19. Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Lumninous Infrared Galaxy Candidates

    Science.gov (United States)

    Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; hide

    2012-01-01

    We present Spitzer 3.6 and 4.5 micrometer photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 m to approximately 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (greater than 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of 7.33 x 10(exp 5) objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 m photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

  20. Galactic Astronomy in the Ultraviolet

    Science.gov (United States)

    Rastorguev, A. S.; Sachkov, M. E.; Zabolotskikh, M. V.

    2017-12-01

    We propose a number of prospective observational programs for the ultraviolet space observatory WSO-UV, which seem to be of great importance to modern galactic astronomy. The programs include the search for binary Cepheids; the search and detailed photometric study and the analysis of radial distribution of UV-bright stars in globular clusters ("blue stragglers", blue horizontal-branch stars, RR Lyrae variables, white dwarfs, and stars with UV excesses); the investigation of stellar content and kinematics of young open clusters and associations; the study of spectral energy distribution in hot stars, including calculation of the extinction curves in the UV, optical and NIR; and accurate definition of the relations between the UV-colors and effective temperature. The high angular resolution of the observatory allows accurate astrometric measurements of stellar proper motions and their kinematic analysis.

  1. The galactic model of GRBs

    Energy Technology Data Exchange (ETDEWEB)

    Colgate, S.A.; Li, H.

    1997-09-01

    The galactic model of gamma ray bursts (GRBs) is based upon the observed production of soft gamma ray repeaters (SGRs) in the galaxy and the consequences of a reasonable model to explain them. In this view GRBs are the long term result of the burn-out conditions of the SGRs in this and in other galaxies. A delay of {approximately} 30 million years before GRBs are being actively produced can be understood as the time required for the ejected matter during the SGR phase to cool, condense, and form planetesimals that are eventually captured by the central neutron star. The amount of disk matter and the interaction between each GRB and the disk determine the rate of burst production and turn-off time of GRBs. The x-ray afterglow as well as optical emission is derived from x-ray fluorescence and ionization of previously ablated matter.

  2. New Results from Spitzer's Journey Through The Earth's Resonant Ring: 2004-2006

    Science.gov (United States)

    Jayaraman, Sumita; Grogan, K.; Bhattacharya, B.; Reach, W. T.

    2006-09-01

    The Spitzer Space Telescope, in its solar orbit, has been drifting away from the Earth - enabling it to trace a path through the Earth's Resonant Ring, specifically, traverse through the resonant dust cloud that follows the Earth. The dust cloud causes the mid-infrared flux in the sky to be higher in the trailing direction when viewed from the Earth. After launch, Spitzer has slowly entered into the dust cloud and has crossed over the peak dust density of the trailing dust cloud. This causes a change in the trailing/leading asymmetry in the background flux. Eventually the leading flux will be higher as Spitzer views the cloud from the opposite side at the end of the mission. We have designed a zodiacal background monitoring program for the ecliptic and north and south ecliptic poles to obtain absolutely calibrated data in the MIPS total power mode. This program includes observations from 2004 to 2006 and will continue into the next observation cycle. We present new results measuring the change in the zodiacal background radiation at 24 microns in combination with science calibration observation observations from IRAC during this period. Further comparison of the multi-wavelength measurements to models shows the detailed ring structure and the provide estimates of the ring dust density in the Resonant Ring. We would like to thank NASA/JPL for funding this program through the Spitzer GO Cycle. We would also like to thank the Spitzer Science Center for helping us to schedule the individual solar system observations after the MIPS campaign dates are fixed and contributing the IRAC calibration observations.

  3. RESOLVING THE ACTIVE GALACTIC NUCLEUS AND HOST EMISSION IN THE MID-INFRARED USING A MODEL-INDEPENDENT SPECTRAL DECOMPOSITION

    Energy Technology Data Exchange (ETDEWEB)

    Hernán-Caballero, Antonio; Alonso-Herrero, Almudena [Instituto de Física de Cantabria, CSIC-UC, Avenida de los Castros s/n, E-39005, Santander (Spain); Hatziminaoglou, Evanthia [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Spoon, Henrik W. W. [Cornell University, CRSR, Space Sciences Building, Ithaca, NY 14853 (United States); Almeida, Cristina Ramos [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Santos, Tanio Díaz [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Hönig, Sebastian F. [School of Physics and Astronomy, University of Southampton, Southampton SO18 1BJ (United Kingdom); González-Martín, Omaira [Centro de Radioastronomía y Astrofísica (CRyA-UNAM), 3-72 (Xangari), 8701, Morelia (Mexico); Esquej, Pilar, E-mail: ahernan@ifca.unican.es [Departamento de Astrofísica, Facultad de CC. Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

    2015-04-20

    We present results on the spectral decomposition of 118 Spitzer Infrared Spectrograph (IRS) spectra from local active galactic nuclei (AGNs) using a large set of Spitzer/IRS spectra as templates. The templates are themselves IRS spectra from extreme cases where a single physical component (stellar, interstellar, or AGN) completely dominates the integrated mid-infrared emission. We show that a linear combination of one template for each physical component reproduces the observed IRS spectra of AGN hosts with unprecedented fidelity for a template fitting method with no need to model extinction separately. We use full probability distribution functions to estimate expectation values and uncertainties for observables, and find that the decomposition results are robust against degeneracies. Furthermore, we compare the AGN spectra derived from the spectral decomposition with sub-arcsecond resolution nuclear photometry and spectroscopy from ground-based observations. We find that the AGN component derived from the decomposition closely matches the nuclear spectrum with a 1σ dispersion of 0.12 dex in luminosity and typical uncertainties of ∼0.19 in the spectral index and ∼0.1 in the silicate strength. We conclude that the emission from the host galaxy can be reliably removed from the IRS spectra of AGNs. This allows for unbiased studies of the AGN emission in intermediate- and high-redshift galaxies—currently inaccesible to ground-based observations—with archival Spitzer/IRS data and in the future with the Mid-InfraRed Instrument of the James Webb Space Telescope. The decomposition code and templates are available at http://denebola.org/ahc/deblendIRS.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  5. The First Simultaneous Microlensing Observations by Two Space Telescopes: Spitzer and Swift Reveal a Brown Dwarf in Event OGLE-2015-BLG-1319

    Science.gov (United States)

    Shvartzvald, Y.; Li, Z.; Udalski, A.; Gould, A.; Sumi, T.; Street, R. A.; Calchi Novati, S.; Hundertmark, M.; Bozza, V.; Beichman, C.; hide

    2016-01-01

    Simultaneous observations of microlensing events from multiple locations allow for the breaking of degeneracies between the physical properties of the lensing system, specifically by exploring different regions of the lens plane and by directly measuring the "microlens parallax". We report the discovery of a 30-65M J brown dwarf orbiting a K dwarf in the microlensing event OGLE-2015-BLG-1319. The system is located at a distance of approximately 5 kpc toward the Galactic Bulge. The event was observed by several ground-based groups as well as by Spitzer and Swift, allowing a measurement of the physical properties. However, the event is still subject to an eight-fold degeneracy, in particular the well-known close-wide degeneracy, and thus the projected separation between the two lens components is either approximately 0.25 au or approximately 45 au. This is the first microlensing event observed by Swift, with the UVOT camera. We study the region of microlensing parameter space to which Swift is sensitive, finding that though Swift could not measure the microlens parallax with respect to ground-based observations for this event, it can be important for other events. Specifically, it is important for detecting nearby brown dwarfs and free-floating planets in high magnification events.

  6. OPEN CLUSTERS IN THE MILKY WAY OUTER DISK: NEWLY DISCOVERED AND UNSTUDIED CLUSTERS IN THE SPITZER GLIMPSE-360, CYG-X, AND SMOG SURVEYS

    International Nuclear Information System (INIS)

    Zasowski, G.; Beaton, R. L.; Hamm, K. K.; Majewski, S. R.; Patterson, R. J.; Babler, B.; Churchwell, E.; Meade, M.; Whitney, B. A.; Benjamin, R. A.; Watson, C.

    2013-01-01

    Open stellar clusters are extremely valuable probes of Galactic structure, star formation, kinematics, and chemical abundance patterns. Near-infrared (NIR) data have enabled the detection of hundreds of clusters hidden from optical surveys, and mid-infrared (MIR) data are poised to offer an even clearer view into the most heavily obscured parts of the Milky Way. We use new MIR images from the Spitzer GLIMPSE-360, Cyg-X, and SMOG surveys to visually identify a large number of open cluster candidates in the outer disk of the Milky Way (65° < l < 265°). Using NIR color-magnitude diagrams, stellar isochrones, and stellar reddening estimates, we derive cluster parameters (metallicity, distance, reddening) for those objects without previous identification and/or parameters in the literature. In total, we present coordinates and sizes of 20 previously unknown open cluster candidates; for 7 of these we also present metallicity, distance, and reddening values. In addition, we provide the first estimates of these values for nine clusters that had been previously cataloged. We compare our cluster sizes and other derived parameters to those in the open cluster catalog of Dias et al. and find strong similarities except for a higher mean reddening for our objects, which signifies our increased detection sensitivity in regions of high extinction. The results of this cluster search and analysis demonstrate the ability of MIR imaging and photometry to augment significantly the current census of open clusters in the Galaxy

  7. The Timeless Legacy of Robert Koch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 9. The Timeless Legacy of Robert Koch - Founder of Medical Microbiology. Jaya S Tyagi. General Article Volume 11 Issue 9 September 2006 pp 20-28. Fulltext. Click here to view fulltext PDF. Permanent link:

  8. The Legacy of 1789: Part 2.

    Science.gov (United States)

    Kirkaldy, James

    1990-01-01

    Honoring the French Revolution's bicentennial, examines its legacy for modern France. Contends that 1789's imprint appears in France's centralized bureaucracy, strong political divisions (conservative-liberal-socialist), church-state separation, and tendency for government to argue ends justify means. Maintains the Revolution also spawned…

  9. George Peabody's (1795-1869) Educational Legacy.

    Science.gov (United States)

    Parker, Franklin; Parker, Betty J.

    During his career, George Peabody financially supported educational endeavors and went beyond the accumulation of money to leave for one's children. His support began in the mid-1800s and his educational legacy remains. He established: (1) a $2 million Peabody Education Fund to promote public schools and teacher training in 12 civil war devastated…

  10. Christian Social Justice Advocate: Contradiction or Legacy?

    Science.gov (United States)

    Edwards, Cher N.

    2012-01-01

    In this article, the relationship between Christian religiosity and the principles of social justice is explored, including the sociopolitical aspects of faith and advocacy. A particular emphasis is placed on the historical legacy and theological relationships between Christianity and social justice. The author concludes with a call for…

  11. Asutosh Mukhopadhyay and his Mathematical Legacy

    Indian Academy of Sciences (India)

    IAS Admin

    In this article, we describe the life and career of the versatile genius, Asutosh Mukhopadhyay. The article offers a few glimpses of his mathe- matical talent and contributions to mathemat- ics, and of his efforts to propagate and foster the study of and research in mathematics. 1. Introduction. The legacy of Asutosh ...

  12. Fundamental Considerations for Biobank Legacy Planning

    Science.gov (United States)

    Fombonne, Benjamin; Watson, Peter Hamilton; Moore, Helen Marie

    2016-01-01

    Biobanking in its various forms is an activity involving the collection of biospecimens and associated data and their storage for differing lengths of time before use. In some cases, biospecimens are immediately used, but in others, they are stored typically for the term of a specified project or in perpetuity until the materials are used up or declared to be of little scientific value. Legacy planning involves preparing for the phase that follows either biobank closure or a significant change at an operational level. In the case of a classical finite collection, this may be brought about by the completion of the initial scientific goals of a project, a loss of funding, or loss of or change in leadership. Ultimately, this may require making a decision about when and where to transfer materials or whether to destroy them. Because biobanking in its entirety is a complex endeavour, legacy planning touches on biobank operations as well as ethical, legal, financial, and governance parameters. Given the expense and time that goes into setting up and maintaining biobanks, coupled with the ethical imperative to appropriately utilize precious resources donated to research, legacy planning is an activity that every biobanking entity should think about. This article describes some of the fundamental considerations for preparing and executing a legacy plan, and we envisage that this article will facilitate dialogue to help inform best practices and policy development in the future. PMID:26890981

  13. LIFTING THE DUSTY VEIL WITH NEAR- AND MID-INFRARED PHOTOMETRY. II. A LARGE-SCALE STUDY OF THE GALACTIC INFRARED EXTINCTION LAW

    International Nuclear Information System (INIS)

    Zasowski, G.; Majewski, S. R.; Indebetouw, R.

    2009-01-01

    We combine near-infrared (Two Micron All Sky Survey) and mid-infrared (Spitzer-IRAC) photometry to characterize the IR extinction law (1.2-8 μm) over nearly 150 deg. of contiguous Milky Way midplane longitude. The relative extinctions in five passbands across these wavelength and longitude ranges are derived by calculating color excess ratios for G and K giant red clump stars in contiguous midplane regions and deriving the wavelength dependence of extinction in each one. Strong, monotonic variations in the extinction law shape are found as a function of angle from the Galactic center, symmetric on either side of it. These longitudinal variations persist even when dense interstellar regions, known a priori to have a shallower extinction curve, are removed. The increasingly steep extinction curves toward the outer Galaxy indicate a steady decrease in the absolute-to-selective extinction ratio (R V ) and in the mean dust grain size at greater Galactocentric angles. We note an increasing strength of the 8 μm extinction inflection at high Galactocentric angles and, using theoretical dust models, show that this behavior is consistent with the trend in R V . Along several lines of sight where the solution is most feasible, A λ /A K s as a function of Galactic radius (R GC ) is estimated and shown to have a Galactic radial dependence. Our analyses suggest that the observed relationship between extinction curve shape and Galactic longitude is due to an intrinsic dependence of the extinction law on Galactocentric radius.

  14. Sustainable legacies for the 2012 Olympic Games.

    Science.gov (United States)

    Shipway, Richard

    2007-05-01

    The London 2012 Olympic and Paralympic Games have the unique potential to deliver sustainable sporting, social, cultural, economic and environmental legacies, not just for London as the host city, but for the whole of Britain. This article focuses primarily on the first three of these potential Olympics legacies. The first area explored is the social legacy as it impacts on host communities; second, the potential educational and cultural legacy of the 2012 Games are examined; and finally, there follows an overview of the health benefits that could result from a sustained increase in mass participation in sport, physical activity and exercise. This appraisal is undertaken through a review of existing Olympic literature and examples are drawn from previous summer and winter Games. This preliminary exploration is followed by the identification of some key challenges to be overcome if the opportunities available to a wide and diverse range of stakeholders are to be fully optimized. The article suggests that the 2012 Games can act as a catalyst for sports development throughout Britain, while also assisting with government cross-cutting agendas such as tackling crime, antisocial behaviour, developing healthy and active communities, improving educational attainment, and combating barriers to participation. In doing so, this article argues that priority should be placed at supporting grassroots sport through greater access to sport in the community, and not solely elite level sports development. The article concludes by suggesting that the 2012 Games provide opportunities to deliver real and tangible changes and most importantly, to afford a higher priority to sport, along with the obvious associated health benefits for Britain as a whole. The underlying challenge as we move towards 2012 is to achieve a positive step change in the attitudes towards sport and physical activity in British society. Achieving this would possibly be the greatest legacy of the 2012 Olympic and

  15. Galactic bulge preferred over dark matter for the Galactic centre gamma-ray excess

    Science.gov (United States)

    Macias, Oscar; Gordon, Chris; Crocker, Roland M.; Coleman, Brendan; Paterson, Dylan; Horiuchi, Shunsaku; Pohl, Martin

    2018-03-01

    An anomalous gamma-ray excess emission has been found in the Fermi Large Area Telescope data1 covering the centre of the Galaxy2,3. Several theories have been proposed for this `Galactic centre excess'. They include self-annihilation of dark-matter particles4, an unresolved population of millisecond pulsars5, an unresolved population of young pulsars6, or a series of burst events7. Here, we report on an analysis that exploits hydrodynamical modelling to register the position of interstellar gas associated with diffuse Galactic gamma-ray emission. We find evidence that the Galactic centre excess gamma rays are statistically better described by the stellar over-density in the Galactic bulge and the nuclear stellar bulge, rather than a spherical excess. Given its non-spherical nature, we argue that the Galactic centre excess is not a dark-matter phenomenon but rather associated with the stellar population of the Galactic bulge and the nuclear bulge.

  16. Galactic Dark Matter and Terrestrial Periodicities

    National Research Council Canada - National Science Library

    Clube, S

    1998-01-01

    .... The Earth may thus be regarded as a probe of the disc environment; and to account for the periodicity, the Galactic disc is required to have a substantial dark matter component ( approx .15 molar mass/cu pc...

  17. White Dwarfs Cosmological and Galactic Probes

    CERN Document Server

    Sion, Edward M; Vennes, Stéphane

    2005-01-01

    The emphasis on white dwarf stars and cosmology arises from the most recent advances in cosmological and galactic structure research in which white dwarf stars are playing a very prominent role. Examples are Type Ia supernovae (i.e. white dwarf supernovae), the origin and evolution of the universe, the age of the galactic disk, cosmochronology using white dwarfs in globular clusters and galactic clusters, and the physics of accretion onto compact (very dense) stars. As an assisting guide to the reader, we have included, by invitation, comprehensive review articles in each of the four major areas of the book, white dwarf supernovae, cosmology, accretion physics and galactic structure. The reviews include introductory material that they build upon. The book is suitable and most useful to advanced undergraduates, graduate students and scientific professionals (e.g. astronomers, astrophysicists, cosmologists, physicists).

  18. Verification and the safeguards legacy

    International Nuclear Information System (INIS)

    Perricos, Demetrius

    2001-01-01

    of Iraq was a case of late detection of undeclared activities, the case of DPRK was a case of prompt detection of discrepancies in the initial declaration through implementation of modem detection techniques, such as environmental sampling, and access to information. Access to the Security Council became important in view of the protracted process of non-compliance. The Model Additional Protocol (INFCIRC 540) agreed in 1997 incorporates the results of the efforts to strengthen the safeguards system and as such provides the possibility for more transparency by the States and more access to locations by the inspectors on the basis of information. It does not provide the broad and intrusive access rights as in the case of Iraq, since such rights are unprecedented and the result of a cease-fire arrangement involving the Security Council. But the expectations are that the broad implementation of the Additional Protocol will result in an effective and efficient safeguards verification system for the future. The on-site verification systems on a national, regional or multinational basis that have been put into operation in the past or are being discussed by States for the implementation of disarmament and non-proliferation conventions related to weapons of mass destruction whether nuclear, chemical or biological, have benefited and will benefit in the future from the guiding experience - both from the strengths and weaknesses -of the IAEA verification system. This is hopefully a legacy for the future of verification

  19. Radioactivity in the galactic plane

    Science.gov (United States)

    Walraven, G. D.; Haymes, R. C.

    1976-01-01

    The paper reports the detection of a large concentration of interstellar radioactivity during balloon-altitude measurements of gamma-ray energy spectra in the band between 0.02 and 12.27 MeV from galactic and extragalactic sources. Enhanced counting rates were observed in three directions towards the plane of the Galaxy; a power-law energy spectrum is computed for one of these directions (designated B 10). A large statistical deviation from the power law in a 1.0-FWHM interval centered near 1.16 MeV is discussed, and the existence of a nuclear gamma-ray line at 1.15 MeV in B 10 is postulated. It is suggested that Ca-44, which emits gamma radiation at 1.156 MeV following the decay of radioactive Sc-44, is a likely candidate for this line, noting that Sc-44 arises from Ti-44 according to explosive models of supernova nucleosynthesis. The 1.16-MeV line flux inferred from the present data is shown to equal the predicted flux for a supernova at a distance of approximately 3 kpc and an age not exceeding about 100 years.

  20. Issues Associated with Tritium Legacy Materials

    International Nuclear Information System (INIS)

    Mills, Michael

    2008-01-01

    This paper highlights some of the issues associated with the treatment of legacy materials linked to research into tritium over many years and also of materials used to contain or store tritium. The aim of the work is to recover tritium where practicable, and to leave the residual materials passively safe, either for disposal or for continued storage. A number of materials are currently stored at AWE which either contain tritium or have been used in tritium processing. It is essential that these materials are characterised such that a strategy may be developed for their safe stewardship, and ultimately for their treatment and disposal. Treatment processes for such materials are determined by the application of best practicable means (BPM) studies in accordance with the requirements of the Environment Agency of England and Wales. Clearly, it is necessary to understand the objectives of legacy material treatment / processing and the technical options available before a definitive BPM study is implemented. The majority of tritium legacy materials with which we are concerned originate from the decommissioning of a facility that was operational from the late 1950's through to the late 1990's when, on post-operative clear-out (POCO), the entire removable and transportable tritium inventory was moved to new, purpose built facilities. One of the principle tasks to be undertaken in the new facilities is the treatment of the legacy materials to recover tritium wherever practicable, and render the residual materials passively safe for disposal or continued storage. Where tritium recovery was not reasonably or technically feasible, then a means to assure continued safe storage was to be devised and implemented. The legacy materials are in the following forms: - Uranium beds which may or may not contain adsorbed tritium gas; - Tritium gas stored in containers; - Tritide targets for neutron generation; - Tritides of a broad spectrum of metals manufactured for research / long

  1. The Zwicky Transient Facility Galactic Plane Survey

    Science.gov (United States)

    Prince, Thomas; Zwicky Transient Facility (ZTF) Project Team

    2018-01-01

    The Zwicky Transient Faciility (ZTF) is a new survey camera mounted on the 1.2m Oschin Schmidt Telescope on Mount Palomar. The camera has a 47 square degree field of view and is expected to start public survey observations in early 2018. The public surveys are undertaken with support provided by the NSF MSIP program. One of the two public surveys is a twice nightly scan of the central Galactic Plane visible from Mount Palomar, one scan in r-band and one in g-band. Publicly accessible data from the survey will be one of two types: (1) prompt alerts of variable activity of Galactic Plane sources using image difference source identification, and (2) photometric light curves of Galactic Plane sources extracted from calibrated images. Data will be made accessible through the Caltech Image Processing and Analysis Center (IPAC). The ZTF Galactic Plane Survey, combined with Gaia and PanSTARRS data, will be an exciting new resource for time domain astronomy observations of Galactic sources.We will describe the details of the ZTF Galactic Plane survey, including estimated coverage of the plane and light curve sampling. We will also describe plans for public access to the data, as well as comment on some of the important science that will be possible using the survey data.

  2. MID-INFRARED SELECTION OF ACTIVE GALACTIC NUCLEI WITH THE WIDE-FIELD INFRARED SURVEY EXPLORER. I. CHARACTERIZING WISE-SELECTED ACTIVE GALACTIC NUCLEI IN COSMOS

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Daniel; Assef, Roberto J.; Eisenhardt, Peter [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-221, Pasadena, CA 91109 (United States); Benford, Dominic J. [NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Blain, Andrew [Department of Physics and Astronomy, University of Leicester, LE1 7RH Leicester (United Kingdom); Cutri, Roc; Griffith, Roger L.; Jarrett, T. H.; Masci, Frank; Tsai, Chao-Wei; Yan, Lin [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Dey, Arjun [National Optical Astronomical Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 (United States); Lake, Sean; Petty, Sara; Wright, E. L. [Physics and Astronomy Department, University of California, Los Angeles, CA 90095 (United States); Stanford, S. A. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Harrison, Fiona; Madsen, Kristin, E-mail: daniel.k.stern@jpl.nasa.gov [Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-07-01

    The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1 - W2 {>=} 0.8 (i.e., [3.4]-[4.6] {>=}0.8, Vega), which identifies 61.9 {+-} 5.4 active galactic nucleus (AGN) candidates per deg{sup 2} to a depth of W2 {approx} 15.0. This implies a much larger census of luminous AGNs than found by typical wide-area surveys, attributable to the fact that mid-infrared selection identifies both unobscured (type 1) and obscured (type 2) AGNs. Optical and soft X-ray surveys alone are highly biased toward only unobscured AGNs, while this simple WISE selection likely identifies even heavily obscured, Compton-thick AGNs. Using deep, public data in the COSMOS field, we explore the properties of WISE-selected AGN candidates. At the mid-infrared depth considered, 160 {mu}Jy at 4.6 {mu}m, this simple criterion identifies 78% of Spitzer mid-infrared AGN candidates according to the criteria of Stern et al. and the reliability is 95%. We explore the demographics, multiwavelength properties and redshift distribution of WISE-selected AGN candidates in the COSMOS field.

  3. New Software for Ensemble Creation in the Spitzer-Space-Telescope Operations Database

    Science.gov (United States)

    Laher, Russ; Rector, John

    2004-01-01

    Some of the computer pipelines used to process digital astronomical images from NASA's Spitzer Space Telescope require multiple input images, in order to generate high-level science and calibration products. The images are grouped into ensembles according to well documented ensemble-creation rules by making explicit associations in the operations Informix database at the Spitzer Science Center (SSC). The advantage of this approach is that a simple database query can retrieve the required ensemble of pipeline input images. New and improved software for ensemble creation has been developed. The new software is much faster than the existing software because it uses pre-compiled database stored-procedures written in Informix SPL (SQL programming language). The new software is also more flexible because the ensemble creation rules are now stored in and read from newly defined database tables. This table-driven approach was implemented so that ensemble rules can be inserted, updated, or deleted without modifying software.

  4. The ATLAS Trigger Simulation with Legacy Software

    CERN Document Server

    Bernius, Catrin; The ATLAS collaboration

    2017-01-01

    Physics analyses at the LHC require accurate simulations of the detector response and the event selection processes, generally done with the most recent software releases. The trigger response simulation is crucial for determination of overall selection efficiencies and signal sensitivities and should be done with the same software release with which data were recorded. This requires potentially running with software dating many years back, the so-called legacy software. Therefore having a strategy for running legacy software in a modern environment becomes essential when data simulated for past years start to present a sizeable fraction of the total. The requirements and possibilities for such a simulation scheme within the ATLAS software framework were examined and a proof-of-concept simulation chain has been successfully implemented. One of the greatest challenges was the choice of a data format which promises long term compatibility with old and new software releases. Over the time periods envisaged, data...

  5. The ATLAS Trigger Simulation with Legacy Software

    CERN Document Server

    Bernius, Catrin; The ATLAS collaboration

    2017-01-01

    Physics analyses at the LHC which search for rare physics processes or measure Standard Model parameters with high precision require accurate simulations of the detector response and the event selection processes. The accurate simulation of the trigger response is crucial for determination of overall selection efficiencies and signal sensitivities. For the generation and the reconstruction of simulated event data, generally the most recent software releases are used to ensure the best agreement between simulated data and real data. For the simulation of the trigger selection process, however, the same software release with which real data were taken should be ideally used. This requires potentially running with software dating many years back, the so-called legacy software. Therefore having a strategy for running legacy software in a modern environment becomes essential when data simulated for past years start to present a sizeable fraction of the total. The requirements and possibilities for such a simulatio...

  6. SPITZER INFRARED SPECTROMETER 16 μm OBSERVATIONS OF THE GOODS FIELDS

    International Nuclear Information System (INIS)

    Teplitz, Harry I.; Chary, Ranga; Elbaz, David; Le Floc'h, Emeric; Dickinson, Mark; Bridge, Carrie; Howell, Justin H.; Siana, Brian; Colbert, James; Scarlata, Claudia; Frayer, David T.; Koo, David C.; Phillips, Andrew; Papovich, Casey; Spinrad, Hyron; Stern, Daniel

    2011-01-01

    We present Spitzer 16 μm imaging of the Great Observatories Origins Deep Survey (GOODS) fields. We survey 150 arcmin 2 in each of the two GOODS fields (North and South), to an average 3σ depth of 40 and 65 μJy, respectively. We detect ∼1300 sources in both fields combined. We validate the photometry using the 3-24 μm spectral energy distribution of stars in the fields compared to Spitzer spectroscopic templates. Comparison with ISOCAM and AKARI observations in the same fields shows reasonable agreement, though the uncertainties are large. We provide a catalog of photometry, with sources cross-correlated with available Spitzer, Chandra, and Hubble Space Telescope data. Galaxy number counts show good agreement with previous results from ISOCAM and AKARI with improved uncertainties. We examine the 16-24 μm flux ratio and find that for most sources it lies within the expected locus for starbursts and infrared luminous galaxies. A color cut of S 16 /S 24 >1.4 selects mostly sources which lie at 1.1 -2 sr -1 .

  7. Physical Properties of Asteroid (10302) 1989 ML, a Potential Spacecraft Target, from Spitzer Observations

    Science.gov (United States)

    Mueller, Michael; Harris, A. W.

    2006-09-01

    We report on results from recent Spitzer observations of near-Earth asteroid (10302) 1989 ML, which is among the lowest-ranking objects in terms of the specific momentum Δv required to reach it from Earth. It was originally considered as a target for Hayabusa and is now under consideration as a target of the planned ESA mission Don Quijote. Unfortunately, little is known about the physical properties of 1989 ML, in particular its size and albedo are unknown. Its exhibits an X type reflection spectrum, so depending on its albedo, 1989 ML may be an E, M, or P type asteroid. Provisional results from thermal-infrared observations carried out with Spitzer indicate that the albedo of 1989 ML is compatible with an M- or E-type classification. We will discuss our results and their implications for the physical properties and the rotation period of 1989 ML, and its importance as a potential spacecraft target. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

  8. MEASURING ORGANIC MOLECULAR EMISSION IN DISKS WITH LOW-RESOLUTION SPITZER SPECTROSCOPY

    International Nuclear Information System (INIS)

    Teske, Johanna K.; Najita, Joan R.; Carr, John S.; Pascucci, Ilaria; Apai, Daniel; Henning, Thomas

    2011-01-01

    We explore the extent to which Spitzer Infrared Spectrograph (IRS) spectra taken at low spectral resolution can be used in quantitative studies of organic molecular emission from disks surrounding low-mass young stars. We use Spitzer IRS spectra taken in both the high- and low-resolution modules for the same sources to investigate whether it is possible to define line indices that can measure trends in the strength of the molecular features in low-resolution data. We find that trends in the HCN emission strength seen in the high-resolution data can be recovered in low-resolution data. In examining the factors that influence the HCN emission strength, we find that the low-resolution HCN flux is modestly correlated with stellar accretion rate and X-ray luminosity. Correlations of this kind are perhaps expected based on recent observational and theoretical studies of inner disk atmospheres. Our results demonstrate the potential of using the large number of low-resolution disk spectra that reside in the Spitzer archive to study the factors that influence the strength of molecular emission from disks. Such studies would complement results for the much smaller number of circumstellar disks that have been observed at high resolution with IRS.

  9. Spitzer and Variable Young Stars: Shining a Spotlight on Circumstellar Disks

    Science.gov (United States)

    Cody, Ann Marie; CSI 2264 Team

    2014-01-01

    Since its launch in 2003, the Spitzer Space Telescope has helped to uncover hundreds of disk bearing young stars in clusters by detecting their infrared excesses. Study of the spectral energy distributions of these objects has shed light on disk evolution, dispersal, and the relationship to planet formation. With the start of the Warm Spitzer Mission, mid-infrared time series observations have opened up a new window into the dynamic nature of these systems. Not only are young stellar objects (YSOs) highly variable, but so are their disks! I will review recent findings on mid-infrared variability in young stars, highlighting the Young Stellar Object Variability project and the joint Spitzer/CoRoT Coordinated Synoptic Investigation of NGC 2264. These efforts have resulted in a comprehensive census and categorization of YSO flux behavior at 0.5 through 4.5 microns, on timescales from hours to months. We now have evidence for multiple simultaneous variability mechanisms, supporting the picture of a highly dynamic star-disk system.

  10. SPITZER IRS SPECTRA OF DEBRIS DISKS IN THE SCORPIUS–CENTAURUS OB ASSOCIATION

    Energy Technology Data Exchange (ETDEWEB)

    Jang-Condell, Hannah [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Chen, Christine H.; Mittal, Tushar; Lisse, Carey M. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Manoj, P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Rd., Mumbai 400005 (India); Watson, Dan [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Nesvold, Erika; Kuchner, Marc [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    2015-08-01

    We analyze spectra obtained with the Spitzer Infrared Spectrograph (IRS) of 110 B-, A-, F-, and G-type stars with optically thin infrared excess in the Scorpius–Centaurus OB association. The ages of these stars range from 11 to 17 Myr. We fit the infrared excesses observed in these sources by Spitzer IRS and the Multiband Imaging Photometer for Spitzer (MIPS) to simple dust models according to Mie theory. We find that nearly all of the objects in our study can be fit by one or two belts of dust. Dust around lower mass stars appears to be closer in than around higher mass stars, particularly for the warm dust component in the two-belt systems, suggesting a mass-dependent evolution of debris disks around young stars. For those objects with stellar companions, all dust distances are consistent with truncation of the debris disk by the binary companion. The gaps between several of the two-belt systems can place limits on the planets that might lie between the belts, potentially constraining the mass and locations of planets that may be forming around these stars.

  11. Olympics Legacy: the London Olympics 2012

    OpenAIRE

    Gulsen, Guler; Holden, Robert

    2010-01-01

    The reasons for proposing a London 2012 bid are outlined in the light of London city planning over the past sixty years. The processes influencing the bid for the London 2012 Olympics are investigated in respect of the lessons from Barcelona and Sydney. The role of environmental\\ud and landscape improvement is examined and the importance of legacy is described and analysed. The cost of Olympiads since Sydney 2000 are described and compared. Then progress of the London 2012 Olympics developmen...

  12. The mycological legacy of Elias Magnus Fries

    OpenAIRE

    Petersen, Ronald H.; Knudsen, Henning

    2015-01-01

    The taxonomic concepts which originated with or were accepted by Elias Magnus Fries were presented during his lifetime in the printed word, illustrative depiction, and in collections of dried specimens. This body of work was welcomed by the mycological and botanical communities of his time: students and associates aided Fries and after his passing carried forward his taxonomic ideas. His legacy spawned a line of Swedish and Danish mycologists intent on perpetuating the Fries tradition: Hampus...

  13. Requalification of Legacy Radioactive Waste in Germany

    International Nuclear Information System (INIS)

    Bandt, Gabriele; Hoffmann, Paulina; Spicher, Gottfried; Filss, Martin; Schauer, Claudia

    2016-01-01

    Conclusion: • Large stocks of legacy radioactive waste exist, which do not comply with the requirements of the Konrad repository. • Requalification campaigns with thousands of waste packages have successfully been carried out. • Quality assurance plans contain all necessary steps of specific (requalification) campaigns and optimize the procedures for each campaign in advance. • When sophisticated measurement equipment was needed an iterative procedure was adopted. Repeated evaluations of the nondestructive res. destructive measurements limited the measures to the necessary limit.

  14. Migration Performance for Legacy Data Access

    Directory of Open Access Journals (Sweden)

    Kam Woods

    2008-12-01

    Full Text Available We present performance data relating to the use of migration in a system we are creating to provide web access to heterogeneous document collections in legacy formats. Our goal is to enable sustained access to collections such as these when faced with increasing obsolescence of the necessary supporting applications and operating systems. Our system allows searching and browsing of the original files within their original contexts utilizing binary images of the original media. The system uses static and dynamic file migration to enhance collection browsing, and emulation to support both the use of legacy programs to access data and long-term preservation of the migration software. While we provide an overview of the architectural issues in building such a system, the focus of this paper is an in-depth analysis of file migration using data gathered from testing our software on 1,885 CD-ROMs and DVDs. These media are among the thousands of collections of social and scientific data distributed by the United States Government Printing Office (GPO on legacy media (CD-ROM, DVD, floppy disk under the Federal Depository Library Program (FDLP over the past 20 years.

  15. A legacy building model for holistic nursing.

    Science.gov (United States)

    Lange, Bernadette; Zahourek, Rothlyn P; Mariano, Carla

    2014-06-01

    This pilot project was an effort to record the historical roots, development, and legacy of holistic nursing through the visionary spirit of four older American Holistic Nurses Association (AHNA) members. The aim was twofold: (a) to capture the holistic nursing career experiences of elder AHNA members and (b) to begin to create a Legacy Building Model for Holistic Nursing. The narratives will help initiate an ongoing, systematic method for the collection of historical data and serve as a perpetual archive of knowledge and inspiration for present and future holistic nurses. An aesthetic inquiry approach was used to conduct in-depth interviews with four older AHNA members who have made significant contributions to holistic nursing. The narratives provide a rich description of their personal and professional evolution as holistic nurses. The narratives are presented in an aesthetic format of the art forms of snapshot, pastiche, and collage rather than traditional presentations of research findings. A synopsis of the narratives is a dialogue between the three authors and provides insight for how a Legacy Model can guide our future. Considerations for practice, education, and research are discussed based on the words of wisdom from the four older holistic nurses.

  16. The Political Legacy of School Accountability Systems

    Directory of Open Access Journals (Sweden)

    Sherman Dorn

    1998-01-01

    Full Text Available The recent battle reported from Washington about proposed national testing program does not tell the most important political story about high stakes tests. Politically popular school accountability systems in many states already revolve around statistical results of testing with high-stakes environments. The future of high stakes tests thus does not depend on what happens on Capitol Hill. Rather, the existence of tests depends largely on the political culture of published test results. Most critics of high-stakes testing do not talk about that culture, however. They typically focus on the practice legacy of testing, the ways in which testing creates perverse incentives against good teaching. More important may be the political legacy, or how testing defines legitimate discussion about school politics. The consequence of statistical accountability systems will be the narrowing of purpose for schools, impatience with reform, and the continuing erosion of political support for publicly funded schools. Dissent from the high-stakes accountability regime that has developed around standardized testing, including proposals for professionalism and performance assessment, commonly fails to consider these political legacies. Alternatives to standardized testing which do not also connect schooling with the public at large will not be politically viable.

  17. Stellar Feedback from Galactic Bulges

    Science.gov (United States)

    Tang, Shikui; Wang, D. Q.

    2009-01-01

    We demonstrate that feedback from galactic bulges can play an essential role in the halo gas dynamics and the evolution of their host galaxies by conducting a series of 1-D and 3-D simulations. In our 1-D models we approximately divide the the bulge stellar feedback into two phases: 1) a starbusrt-induced blastwave from the formation of bulge built up through frequent major mergers at high redshift and 2) a gradual feedback in forms of stellar wind and Type Ia SNe from low mass stars. Our simulations show that the combination of the two-phase feedback can heat the surrounding gas beyond the virial radius and stop further gas accretion, which naturally produces a baryon deficit around MW-like galaxies and explains the lack of large-scale X-ray halos, consistent with observations. The hot gas dynamics depends sensitively on the environment and bulge formation history. This dependency may account for the large dispersion in the X-ray luminosities of the galaxies with similar L_B. In the 3-D simulations, we examine the spatial, thermal, and chemical substructures and their effects on X-ray measurements. The sporadic SN explosion creates wealth of filamentary and shell-like structures in the hot gas and produces a broad lognormal-like emission-measure distribution, which enhances the X-ray emission at a low and high temperatures. The luminosity at 0.3-2.0 keV band is nearly tripled due to the gas structures. We find that the SN Ia ejecta are not well-mixed with the ambient medium within the bulge scale, and the X-ray emission is primarily from shocked stellar wind materials which in general has low metallicity.

  18. Legacy sample disposition project. Volume 2: Final report

    International Nuclear Information System (INIS)

    Gurley, R.N.; Shifty, K.L.

    1998-02-01

    This report describes the legacy sample disposition project at the Idaho Engineering and Environmental Laboratory (INEEL), which assessed Site-wide facilities/areas to locate legacy samples and owner organizations and then characterized and dispositioned these samples. This project resulted from an Idaho Department of Environmental Quality inspection of selected areas of the INEEL in January 1996, which identified some samples at the Test Reactor Area and Idaho Chemical Processing Plant that had not been characterized and dispositioned according to Resource Conservation and Recovery Act (RCRA) requirements. The objective of the project was to manage legacy samples in accordance with all applicable environmental and safety requirements. A systems engineering approach was used throughout the project, which included collecting the legacy sample information and developing a system for amending and retrieving the information. All legacy samples were dispositioned by the end of 1997. Closure of the legacy sample issue was achieved through these actions

  19. Galactic Habitable Zone and Astrobiological Complexity

    Science.gov (United States)

    Vukotic, B.

    2012-12-01

    This is a short thesis description and for the sake of brevity most things are left out. For more details, those interested are further directed to the thesis related papers in this article reference list. Thesis itself is available at the University of Belgrade library "Svetozar Markovic" (Serbian version only). In this thesis we study the astrobiological history of the Galactic habitable zone through the means of numerical modeling. First group of simulations are unidimensional (time-axis) toy models examine the influence of global regulation mechanisms (gamma-ray bursts and supernovae) on temporal evolution of Galactic astrobiological complexity. It is shown that under the assumption of global regulation classical anti SETI arguments can be undermined. Second group of simulations are more complex bidimensional probabilistic cellular automata models of the Galactic thin disk. They confirm the findings of the toy models and give some insights into the spatial clustering of astrobiological complexity. As a new emerging multidisciplinary science the basic concepts of astrobiology are poorly understood and although all the simulations present here do not include some basic physics (such as Galactic kinematics and dynamics), the input parameters are somewhat arbitrary and could use a future refinement (such as the boundaries of the Galactic habitable zone). This is the cause for low weight and high uncertainty in the output results of the simulations. However, the probabilistic cellular automata has shown as a highly adaptable modeling platform that can simulate various class of astrobiological models with great ease.

  20. Quantitative evaluation of legacy phosphorus and its spatial distribution.

    Science.gov (United States)

    Lou, Hezhen; Zhao, Changsen; Yang, Shengtian; Shi, Liuhua; Wang, Yue; Ren, Xiaoyu; Bai, Juan

    2018-04-01

    A phosphorus resource crisis threatens the security of global crop production, especially in developing countries like China and Brazil. Legacy phosphorus (legacy-P), which is left behind in agricultural soil by over-fertilization, can help address this issue as a new resource in the soil phosphorus pool. However, issues involved with calculating and defining the spatial distribution of legacy-P hinder its future utilization. To resolve these issues, this study applied remote sensing and ecohydrological modeling to precisely quantify legacy-P and define its spatial distribution in China's Sanjiang Plain from 2000 to 2014. The total legacy-P in the study area was calculated as 579,090 t with an annual average of 38,600 t; this comprises 51.83% of the phosphorus fertilizer applied annually. From 2000 to 2014, the annual amount of legacy-P increased by more than 3.42-fold, equivalent to a 2460-ton increase each year. The spatial distribution of legacy-P showed heterogeneity and agglomeration in this area, with peaks in cultivated land experiencing long-term agricultural development. This study supplies a new approach to finding legacy-P in soil as a precondition for future utilization. Once its spatial distribution is known, legacy-P can be better utilized in agriculture to help alleviate the phosphorus resource crisis. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Transforming Cobol Legacy Software to a Generic Imperative Model

    National Research Council Canada - National Science Library

    Moraes, DinaL

    1999-01-01

    .... This research develops a transformation system to convert COBOL code into a generic imperative model, recapturing the initial design and deciphering the requirements implemented by the legacy code...

  2. The IAC stripe82 legacy project

    Science.gov (United States)

    Román, Javier; Fliri, Juergen; Trujillo, Ignacio

    2017-03-01

    We present new deep co-adds of data taken within Stripe 82 of the Sloan Digital Sky Survey (SDSS), especially stacked to reach the faintest surface brightness limits of this data set. Our reduction puts special emphasis on preserving the characteristics of the background (sky + diffuse light) in the input images using a non-aggressive sky subtraction strategy, resulting in an exquisite quality on extremely faint structures. The IAC Stripe 82 co-adds offer a rather unique possibility to study the low surface brightness Universe like stellar haloes and disc truncations, low surface brightness, tidal galactic interactions, extremely faint dwarf galaxies, intra-cluster light or diffuse light from galactic dust. The imaging data is publicly available at http://www.iac.es/proyecto/stripe82/.

  3. ARGOS - II. The Galactic bulge survey

    Science.gov (United States)

    Freeman, K.; Ness, M.; Wylie-de-Boer, E.; Athanassoula, E.; Bland-Hawthorn, J.; Asplund, M.; Lewis, G.; Yong, D.; Lane, R.; Kiss, L.; Ibata, R.

    2013-02-01

    We describe the motivation, field locations and stellar selection for the Abundances and Radial velocity Galactic Origins Survey (ARGOS) spectroscopic survey of 28 000 stars in the bulge and inner disc of the Milky Way galaxy across latitudes of b = -5° to -10°. The primary goal of this survey is to constrain the formation processes of the bulge and establish whether it is predominantly a merger or instability remnant. From the spectra (R = 11 000), we have measured radial velocities and determined stellar parameters, including metallicities and [α/Fe] ratios. Distances were estimated from the derived stellar parameters and about 14 000 stars are red giants within 3.5 kpc of the Galactic Centre. In this paper, we present the observations and analysis methods. Subsequent papers (III and IV) will discuss the stellar metallicity distribution and kinematics of the Galactic bulge and inner disc, and the implications for the formation of the bulge.

  4. Pilot observations for MALT-45: a Galactic plane survey at 7 mm

    Science.gov (United States)

    Jordan, C. H.; Walsh, A. J.; Lowe, V.; Lo, N.; Purcell, C. R.; Voronkov, M. A.; Longmore, S. N.

    2013-02-01

    We introduce the Millimetre Astronomer's Legacy Team - 45 GHz (MALT-45) Galactic plane survey and describe pilot survey results with the Australia Telescope Compact Array (ATCA). The pilot survey was conducted to test the instrumentation and observational technique of MALT-45, before commencing the full survey. We mapped two half-square degree regions within the southern Galactic plane around the G333 giant molecular cloud, using fast mosaic mapping. Using the new Compact Array Broad-band Backend on the ATCA, we were able to observe two 2048 MHz spectral windows, centred on frequencies 43.2 and 48.2 GHz. Although only a coarse spectral resolution of around 7 km s-1 was available to us, we detect widespread, extended emission in the CS (1-0) ground state transition. We also detect eight Class I CH3OH masers at 44 GHz and three SiO masers in vibrationally excited (1-0) transitions. We also detect the H53α radio recombination line, non-vibrationally excited SiO (1-0) and emission in the CH3OH 11-00 A+ line.

  5. X-raying galaxies: a Chandra legacy.

    Science.gov (United States)

    Wang, Q Daniel

    2010-04-20

    This presentation reviews Chandra's major contribution to the understanding of nearby galaxies. After a brief summary on significant advances in characterizing various types of discrete x-ray sources, the presentation focuses on the global hot gas in and around galaxies, especially normal ones like our own. The hot gas is a product of stellar and active galactic nuclear feedback--the least understood part in theories of galaxy formation and evolution. Chandra observations have led to the first characterization of the spatial, thermal, chemical, and kinetic properties of the gas in our galaxy. The gas is concentrated around the galactic bulge and disk on scales of a few kiloparsec. The column density of chemically enriched hot gas on larger scales is at least an order magnitude smaller, indicating that it may not account for the bulk of the missing baryon matter predicted for the galactic halo according to the standard cosmology. Similar results have also been obtained for other nearby galaxies. The x-ray emission from hot gas is well correlated with the star formation rate and stellar mass, indicating that the heating is primarily due to the stellar feedback. However, the observed x-ray luminosity of the gas is typically less than a few percent of the feedback energy. Thus the bulk of the feedback (including injected heavy elements) is likely lost in galaxy-wide outflows. The results are compared with simulations of the feedback to infer its dynamics and interplay with the circumgalactic medium, hence the evolution of galaxies.

  6. The case for a primordial galactic field

    International Nuclear Information System (INIS)

    Kulsrud, R.

    1989-01-01

    Two possible theories of the origin of the galactic magnetic field are discussed. It is shown that the first theory, of its generation by a fast magnetic dynamo, is limited by the properties of the interstellar medium which suppress the small scale motions in the turbulence, and thus inhibit the generation of the field from a small seed field. The second theory that the galactic field is a relic of a general cosmic magnetic field existing prior to formation of our galaxy is discussed. It is pointed out that such a field would evolve to a field very similiar to that which we see today. (author). 4 refs

  7. Dynamics of black holes in galactic centres.

    Science.gov (United States)

    Hemsendorf, M.

    The dynamics of a massive binary system in a galactic nucleus are presented. These are the first results from simulations applying a hybrid "self consistent field" (SCF) and direct Aarseth N-body integrator (NBODY6), which synthesises the advantages of the direct force calculation with the efficiency of the field method. The code is aimed for use on parallel architectures and is therefore applicable for collisional N-body integrations with extraordinarily large particle numbers (>105). It opens the perspective to simulate the dynamics of globular clusters with realistic collisional relaxation, as well as stellar systems surrounding a supermassive black hole in galactic nuclei.

  8. The Legacy of Utah's Country Schools, 1847-1896. Country School Legacy: Humanities on the Frontier.

    Science.gov (United States)

    Birkinshaw, Scott B.

    This section of the Country School Legacy: Humanities on the Frontier Project, funded by the National Endowment for the Humanities and sponsored by the Mountain Plains Library Association, traces the development of schools in Utah during the Territorial Period (1847-1896). Following a discussion of the influence of the Church of Jesus Christ of…

  9. Portuguese Cistercian Churches - An acoustic legacy

    Science.gov (United States)

    Rodrigues, Fabiel G.; Lanzinha, João C. G.; Martins, Ana M. T.

    2017-10-01

    The Cistercian Order (11th century) stands out as an apologist of the simplicity and austerity of the space. According to the Order of Cîteaux, only with an austere space, without any distractions, the true spiritual contemplation is achieved. This Order was an aggregator and consolidator pole during the Christian Reconquest. Thus, as it happens with other Religious Orders, Cîteaux has a vast heritage legacy. This heritage is witness, not only of the historical, but also social, political, and spiritual evolution. This legacy resumes the key principles to an austere liturgy, which requirements, in the beginning, are based on the simplicity of worship and of the connection between man and God. Later, these requirements allowed the development of the liturgy itself and its relation with the believers. Consequently, it can be concisely established an empirical approach between the Cistercian churches and the acoustics conditioning of these spaces. This outcome is fundamental in order to understand the connection between liturgy and the conception of the Cistercian churches as well as the constructed space and its history. So, an analysis of these principles is essential to establish the relation between acoustic and religious buildings design throughout history. It is also a mean of understanding the knowledge of acoustics principles that the Cistercian Order bequeathed to Portugal. This paper presents an empirical approach on Cistercian monastic churches acoustics. These spaces are the place where the greatest acoustic efforts are concentrated and it is also the space where the liturgy reaches greater importance. On the other hand, Portugal is a country which has an important Cistercian legacy over several periods of history. Consequently, the Portuguese Cistercian monastic churches are representative of the development of the liturgy, the design of spaces and of the acoustic requirements of their churches since the 12th century until the 21st century and it is of

  10. Legacy Risk Measure for Environmental Waste

    International Nuclear Information System (INIS)

    Eide, S. A.; Nitschke, R. L.

    2002-01-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) is investigating the development of a comprehensive and quantitative risk model framework for environmental management activities at the site. Included are waste management programs (high-level waste, transuranic waste, low-level waste, mixed low-level waste, spent nuclear fuel, and special nuclear materials), major environmental restoration efforts, major decontamination and decommissioning projects, and planned long-term stewardship activities. Two basic types of risk estimates are included: risks from environmental management activities, and long-term legacy risks from wastes/materials. Both types of risks are estimated using the Environment, Safety, and Health Risk Assessment Program (ESHRAP) developed at the INEEL. Given these two types of risk calculations, the following evaluations can be performed: risk evaluation of an entire program (covering waste/material as it now exists through disposal or other e nd states); risk comparisons of alternative programs or activities; comparisons of risk benefit versus risk cost for activities or entire programs; ranking of programs or activities by risk; ranking of wastes/materials by risk; evaluation of site risk changes with time as activities progress; and integrated performance measurement using indicators such as injury/death and exposure rates. This paper discusses the definition and calculation of legacy risk measures and associated issues. The legacy risk measure is needed to support three of the seven types of evaluations listed above: comparisons of risk benefit versus risk cost, ranking of wastes/materials by risk, and evaluation of site risk changes with time

  11. Legacy Nitrate Impacts on Groundwater and Streams

    Science.gov (United States)

    Tesoriero, A. J.; Juckem, P. F.; Miller, M. P.

    2017-12-01

    Decades of recharge of high-nitrate groundwater have created a legacy—a mass of high-nitrate groundwater—that has implications for future nitrate concentrations in groundwater and in streams. In the United States, inorganic nitrogen fertilizer applications to the land surface have increased ten-fold since 1950, resulting in sharp increases in nitrate concentrations in recharging groundwater, which pose a risk to deeper groundwater and streams. This study assesses the factors that control time lags and eventual concentrations of legacy nitrate in groundwater and streams. Results from the USGS National Water-Quality Assessment Project are presented which elucidate nitrate trends in recharging groundwater, delineate redox zones and assess groundwater and stream vulnerability to legacy nitrate sources on a regional scale. This study evaluated trends and transformations of agricultural chemicals based on groundwater age and water chemistry data along flow paths from recharge areas to streams at 20 study sites across the United States. Median nitrate recharge concentrations in these agricultural areas have increased markedly over the last 50 years, from 4 to 7.5 mg N/L. The effect that nitrate accumulation in shallow aquifers will have on drinking water quality and stream ecosystems is dependent on the redox zones encountered along flow paths and on the age distribution of nitrate discharging to supply wells and streams. Delineating redox zones on a regional scale is complicated by the spatial variability of reaction rates. To overcome this limitation, we applied logistic regression and machine learning techniques to predict the probability of a specific redox condition in groundwater in the Chesapeake Bay watershed and the Fox-Wolf-Peshtigo study area in Wisconsin. By relating redox-active constituent concentrations in groundwater samples to indicators of residence time and/or electron donor availability, we were able to delineate redox zones on a regional scale

  12. Radioactive legacies from medicine and industry

    International Nuclear Information System (INIS)

    Linder, R.; Rodriguez, J.

    2005-01-01

    Due to the unintended disposal of radioactive legacies (waste from medicine, industry or private persons) radioactive material occasionally enters the disposal ways of conventional waste. The Swiss Federal Office of Public Health (SFOPH) and the Swiss accident Insurance Fund (Swiss) are the licensing authorities and regulatory agencies of the handling with radioactive materials for non-nuclear use. The aim is to avoid such incidents with concrete measures and so to preserve men and environment from the negative effect of not correctly disposed radioactive waste. (orig.)

  13. Eventscapes and the creation of event legacies

    OpenAIRE

    Brown, G.; Lee, I.S.; King, Katherine; Shipway, Richard

    2015-01-01

    Attention is directed to the difference in event legacies created by mega-events which often cause dramatic physical changes in urban environments and those which accompany events which leave very little imprint on the landscape where they are held. The Tour Down Under cycle race, which is held annually in South Australia, is examined as an example of the latter. The spatial pattern of the event and the range of settings which support it are presented as an eventscape by drawing on concepts s...

  14. Integrating commercial and legacy systems with EPICS

    International Nuclear Information System (INIS)

    Hill, J.O.; Kasemir, K.U.

    1997-01-01

    The Experimental Physics and Industrial Control System (EPICS) is a software toolkit, developed by a worldwide collaboration, which significantly reduces the level of effort required to implement a new control system. Recent developments now also significantly reduce the level of effort required to integrate commercial, legacy and/or site-authored control systems with EPICS. This paper will illustrate with an example both the level and type of effort required to use EPICS with other control system components as well as the benefits that may arise

  15. THE CHANDRA COSMOS-LEGACY SURVEY: THE z > 3 SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, S.; Civano, F.; Urry, C. M. [Yale Center for Astronomy and Astrophysics, 260 Whitney Avenue, New Haven, CT 06520 (United States); Salvato, M. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching bei München (Germany); Shankar, F. [Department of Physics and Astronomy, University of Southampton, Highfield, SO17 1BJ (United Kingdom); Comastri, A.; Lanzuisi, G.; Vignali, C.; Zamorani, G.; Brusa, M.; Gilli, R. [INAF–Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna (Italy); Elvis, M. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Trakhtenbrot, B.; Schawinski, K. [Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Allevato, V. [Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-00014 Helsinki (Finland); Fiore, F. [INAF–Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monte Porzio Catone (Italy); Griffiths, R. [Physics and Astronomy Department, Natural Sciences Division, University of Hawaii at Hilo, 200 W. Kawili Street, Hilo, HI 96720 (United States); Hasinger, G. [Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822 (United States); Miyaji, T. [Instituto de Astronomía sede Ensenada, Universidad Nacional Autónoma de México, Km. 103, Carret. Tijunana-Ensenada, Ensenada, BC (Mexico); Treister, E. [Universidad de Concepción, Departamento de Astronomía, Casilla 160-C, Concepción (Chile)

    2016-08-20

    We present the largest high-redshift (3 < z < 6.85) sample of X-ray-selected active galactic nuclei (AGNs) on a contiguous field, using sources detected in the Chandra COSMOS-Legacy survey. The sample contains 174 sources, 87 with spectroscopic redshift and the other 87 with photometric redshift (z {sub phot}). In this work, we treat z {sub phot} as a probability-weighted sum of contributions, adding to our sample the contribution of sources with z {sub phot} < 3 but z {sub phot} probability distribution >0 at z > 3. We compute the number counts in the observed 0.5–2 keV band, finding a decline in the number of sources at z > 3 and constraining phenomenological models of the X-ray background. We compute the AGN space density at z > 3 in two different luminosity bins. At higher luminosities (log L (2–10 keV) > 44.1 erg s{sup −1}), the space density declines exponentially, dropping by a factor of ∼20 from z ∼ 3 to z ∼ 6. The observed decline is ∼80% steeper at lower luminosities (43.55 erg s{sup −1} < logL(2–10 keV) < 44.1 erg s{sup −1}) from z ∼ 3 to z ∼ 4.5. We study the space density evolution dividing our sample into optically classified Type 1 and Type 2 AGNs. At log L (2–10 keV) > 44.1 erg s{sup −1}, unobscured and obscured objects may have different evolution with redshift, with the obscured component being three times higher at z ∼ 5. Finally, we compare our space density with predictions of quasar activation merger models, whose calibration is based on optically luminous AGNs. These models significantly overpredict the number of expected AGNs at log L (2–10 keV) > 44.1 erg s{sup −1} with respect to our data.

  16. First results from the INTEGRAL galactic plane scans

    DEFF Research Database (Denmark)

    Winkler, C.; Gehrels, N.; Schonfelder, V.

    2003-01-01

    Scans of the Galactic plane performed at regular intervals constitute a key element of the guaranteed time observations of the INTEGRAL observing programme. These scans are done for two reasons: frequent monitoring of the Galactic plane in order to detect transient sources, and time resolved...... mapping of the Galactic plane in continuum and diffuse line emission. This paper describes first results obtained from the Galactic plane scans executed so far during the early phase (Dec. 2002-May 2003) of the nominal mission....

  17. SPITZER TRANSITS OF THE SUPER-EARTH GJ1214b AND IMPLICATIONS FOR ITS ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Fraine, Jonathan D.; Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Gillon, Michaeel; Jehin, Emmanueel [Institute d' Astrophysique et de Geophysique, Universite de Liege, Liege (Belgium); Demory, Brice-Olivier; Benneke, Bjoern; Seager, Sara [Department of Earth, Atmospheric and Planetary Sciences, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Lewis, Nikole K. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Knutson, Heather [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Desert, Jean-Michel, E-mail: jfraine@astro.umd.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)

    2013-03-10

    We observed the transiting super-Earth exoplanet GJ1214b using warm Spitzer at 4.5 {mu}m wavelength during a 20 day quasi-continuous sequence in 2011 May. The goals of our long observation were to accurately define the infrared transit radius of this nearby super-Earth, to search for the secondary eclipse, and to search for other transiting planets in the habitable zone of GJ1214. We here report results from the transit monitoring of GJ1214b, including a reanalysis of previous transit observations by Desert et al. In total, we analyze 14 transits of GJ1214b at 4.5 {mu}m, 3 transits at 3.6 {mu}m, and 7 new ground-based transits in the I+z band. Our new Spitzer data by themselves eliminate cloudless solar composition atmospheres for GJ1214b, and methane-rich models from Howe and Burrows. Using our new Spitzer measurements to anchor the observed transit radii of GJ1214b at long wavelengths, and adding new measurements in I+z, we evaluate models from Benneke and Seager and Howe and Burrows using a {chi}{sup 2} analysis. We find that the best-fit model exhibits an increase in transit radius at short wavelengths due to Rayleigh scattering. Pure water atmospheres are also possible. However, a flat line (no atmosphere detected) remains among the best of the statistically acceptable models, and better than pure water atmospheres. We explore the effect of systematic differences among results from different observational groups, and we find that the Howe and Burrows tholin-haze model remains the best fit, even when systematic differences among observers are considered.

  18. Spitzer/IRS Observations Of Multiple Main-Belt And Binary Near-Earth Asteroids

    Science.gov (United States)

    Enriquez, J. Emilio; Marchis, F.; Emery, J. P.; Im, S.

    2010-10-01

    Since the discovery of Ida's companion in 1993, 195 companions of asteroids have been discovered. To understand the formation process of these interesting bodies, their physical properties such as their bulk density, size, shape, and surface roughness need to be determined. During the Spitzer Cycle-4, we obtained IRS thermal emission spectra (5-42 um) of 23 known binary systems. The majority of asteroids are from the main-belt (16), while the rest are NEOs (7). After extracting the thermal spectra, we used a modified Standard Thermal Model (STM) to calculate their equivalent diameter (from 0.8 km to 237 km), their albedo (from 0.04 for C-type to 0.394 for a V-type) and their beaming factor related to the surface roughness and thermal inertia. We derive their emissivity spectra, which is useful to detect silicate features. Combining these measurements with 3D-models of these multiple asteroid systems obtained by lightcurve inversion, we should be able to derive an accurate estimate of their bulk-density and contrast them with their taxonomic classes. Preliminary studies by Marchis et al. (2008)1, suggested a relationship between bulk density and the taxonomic class of asteroids, which varies from 0.9 g/cc for C-complex to 2.4 g/cc for S-complex asteroids. The National Science Foundation supported this research under award number AAG-0807468. It was conducted with the Spitzer space telescope, which is operated by JPL under a contract with NASA. 1 Marchis et al. , 2008, "Mid-infrared Spectra of Binary Asteroids With Spitzer/IRS", 40th DPS Meeting, Bulletin of the American Astronomical Society, 40, 508

  19. Multiple Asteroid Systems: Dimensions and Thermal Properties from Spitzer Space Telescope and Ground-based Observations

    Science.gov (United States)

    Marchis, F.; Enriquez, J. E.; Emery, J. P.; Mueller, M.; Baek, M.; Pollock, J.; Assafin, M.; Matins, R. Vieira; Berthier, J.; Vachier, F.; hide

    2012-01-01

    We collected mid-IR spectra from 5.2 to 38 microns using the Spitzer Space Telescope Infrared Spectrograph of 28 asteroids representative of all established types of binary groups. Photometric light curves were also obtained for 14 of them during the Spitzer observations to provide the context of the observations and reliable estimates of their absolute magnitudes. The extracted mid-IR spectra were analyzed using a modified standard thermal model (STM) and a thermophysical model (TPM) that takes into account the shape and geometry of the large primary at the time of the Spitzer observation. We derived a reliable estimate of the size, albedo, and beaming factor for each of these asteroids, representing three main taxonomic groups: C, S, and X. For large (volume-equivalent system diameter Deq > 130 km) binary asteroids, the TPM analysis indicates a low thermal inertia (Lambda thermally insulating regolith. The smaller (surface-equivalent system diameter Deff < 17 km) asteroids also show some emission lines of minerals, but they are significantly weaker, consistent with regoliths with coarser grains, than those of the large binary asteroids. The average bulk densities of these multiple asteroids vary from 0.7-1.7 g/cu cm (P-, C-type) to approx. 2 g/cu cm (S-type). The highest density is estimated for the M-type (22) Kalliope (3.2 +/- 0.9 g/cu cm). The spectral energy distributions (SEDs) and emissivity spectra, made available as a supplement document, could help to constrain the surface compositions of these asteroids.

  20. Biological field stations: research legacies and sites for serendipity

    Science.gov (United States)

    William K. Michener; Keith L. Bildstein; Arthur McKee; Robert R. Parmenter; William W. Hargrove; Deedra McClearn; Mark Stromberg

    2009-01-01

    Biological field stations are distributed throughout North America, capturing much of the ecological variability present at the continental scale and encompassing many unique habitats. In addition to their role in supporting research and education, field stations offer legacies of data, specimens, and accumulated knowledge. Such legacies often provide the only...

  1. Jack Wescott and Donald F. Smith. The Legacy Project

    Science.gov (United States)

    Moye, Johnny J.; Wescott, Jack W.; Smith, Donald F.

    2017-01-01

    This is the tenth in a series of articles entitled "The Legacy Project." The Legacy Project focuses on the lives and actions of leaders who have forged our profession into what it is today. Members of the profession owe a debt of gratitude to these leaders. One simple way to demonstrate that gratitude is to recognize these leaders and…

  2. Combining Spitzer Parallax and Keck II Adaptive Optics Imaging to Measure the Mass of a Solar-like Star Orbited by a Cold Gaseous Planet Discovered by Microlensing

    Science.gov (United States)

    Beaulieu, J.-P.; Batista, V.; Bennett, D. P.; Marquette, J.-B.; Blackman, J. W.; Cole, A. A.; Coutures, C.; Danielski, C.; Dominis Prester, D.; Donatowicz, J.; Fukui, A.; Koshimoto, N.; Lončarić, K.; Morales, J. C.; Sumi, T.; Suzuki, D.; Henderson, C.; Shvartzvald, Y.; Beichman, C.

    2018-02-01

    To obtain accurate mass measurements for cold planets discovered by microlensing, it is usually necessary to combine light curve modeling with at least two lens mass–distance relations. The physical parameters of the planetary system OGLE-2014-BLG-0124L have been constrained thanks to accurate parallax effect between ground-based and simultaneous space-based Spitzer observations. Here, we resolved the source+lens star from sub-arcsecond blends in H-band using adaptive optics (AO) observations with NIRC2 mounted on Keck II telescope. We identify additional flux, coincident with the source to within 160 mas. We estimate the potential contributions to this blended light (chance-aligned star, additional companion to the lens or to the source) and find that 85% of the NIR flux is due to the lens star at H L = 16.63 ± 0.06 and K L = 16.44 ± 0.06. We combined the parallax constraint and the AO constraint to derive the physical parameters of the system. The lensing system is composed of a mid-late type G main sequence star of M L = 0.9 ± 0.05 M ⊙ located at D L = 3.5 ± 0.2 kpc in the Galactic disk. Taking the mass ratio and projected separation from the original study leads to a planet of M p = 0.65 ± 0.044 M Jupiter at 3.48 ± 0.22 au. Excellent parallax measurements from simultaneous ground-space observations have been obtained on the microlensing event OGLE-2014-BLG-0124, but it is only when they are combined with ∼30 minutes of Keck II AO observations that the physical parameters of the host star are well measured.

  3. SPITZER ULTRA FAINT SURVEY PROGRAM (SURFS UP). II. IRAC-DETECTED LYMAN-BREAK GALAXIES AT 6 ≲ z ≲ 10 BEHIND STRONG-LENSING CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Kuang-Han; Bradač, Maruša; Hoag, Austin; Cain, Benjamin; Lubin, L. M.; Knight, Robert I. [University of California Davis, 1 Shields Avenue, Davis, CA 95616 (United States); Lemaux, Brian C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Ryan, R. E. Jr.; Brammer, Gabriel B. [Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Castellano, Marco; Amorin, Ricardo; Fontana, Adriano; Merlin, Emiliano [INAF—Osservatorio Astronomico di Roma Via Frascati 33, I-00040 Monte Porzio Catone (Italy); Schmidt, Kasper B. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Schrabback, Tim [Argelander-Institut für Astronomie, Auf Dem Hügel 71, D-53121 Bonn (Germany); Treu, Tommaso [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095 (United States); Gonzalez, Anthony H. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Linden, Anja von der, E-mail: khhuang@ucdavis.edu, E-mail: astrokuang@gmail.com [Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305 (United States)

    2016-01-20

    We study the stellar population properties of the IRAC-detected 6 ≲ z ≲ 10 galaxy candidates from the Spitzer UltRa Faint SUrvey Program. Using the Lyman Break selection technique, we find a total of 17 galaxy candidates at 6 ≲ z ≲ 10 from Hubble Space Telescope images (including the full-depth images from the Hubble Frontier Fields program for MACS 1149 and MACS 0717) that have detections at signal-to-noise ratios  ≥ 3 in at least one of the IRAC 3.6 and 4.5 μm channels. According to the best mass models available for the surveyed galaxy clusters, these IRAC-detected galaxy candidates are magnified by factors of ∼1.2–5.5. Due to the magnification of the foreground galaxy clusters, the rest-frame UV absolute magnitudes M{sub 1600} are between −21.2 and −18.9 mag, while their intrinsic stellar masses are between 2 × 10{sup 8}M{sub ⊙} and 2.9 × 10{sup 9}M{sub ⊙}. We identify two Lyα emitters in our sample from the Keck DEIMOS spectra, one at z{sub Lyα} = 6.76 (in RXJ 1347) and one at z{sub Lyα} = 6.32 (in MACS 0454). We find that 4 out of 17 z ≳ 6 galaxy candidates are favored by z ≲ 1 solutions when IRAC fluxes are included in photometric redshift fitting. We also show that IRAC [3.6]–[4.5] color, when combined with photometric redshift, can be used to identify galaxies which likely have strong nebular emission lines or obscured active galactic nucleus contributions within certain redshift windows.

  4. Observations of V592 Cassiopeiae with the Spitzer Space Telescope - Dust in the Mid-Infrared

    OpenAIRE

    Hoard, D. W.; Kafka, Stella; Wachter, Stefanie; Howell, Steve B.; Brinkworth, Carolyn S.; Ciardi, David R.; Szkody, Paula; Belle, Kunegunda; Froning, Cynthia; van Belle, Gerard

    2008-01-01

    We present the ultraviolet-optical-infrared spectral energy distribution of the low inclination novalike cataclysmic variable (CV) V592 Cassiopeiae, including new mid-infrared observations from 3.5 to 24 μm obtained with the Spitzer Space Telescope. At wavelengths shortward of 8 μm, the spectral energy distribution of V592 Cas is dominated by the steady state accretion disk, but there is flux density in excess of the summed stellar components and accretion disk at longer wavelengths. Reproduc...

  5. REPEATABILITY OF SPITZER/IRAC EXOPLANETARY ECLIPSES WITH INDEPENDENT COMPONENT ANALYSIS

    International Nuclear Information System (INIS)

    Morello, G.; Waldmann, I. P.; Tinetti, G.

    2016-01-01

    The research of effective and reliable detrending methods for Spitzer data is of paramount importance for the characterization of exoplanetary atmospheres. To date, the totality of exoplanetary observations in the mid- and far-infrared, at wavelengths >3 μm, have been taken with Spitzer. In some cases, in past years, repeated observations and multiple reanalyses of the same data sets led to discrepant results, raising questions about the accuracy and reproducibility of such measurements. Morello et al. (2014, 2015) proposed a blind-source separation method based on the Independent Component Analysis of pixel time series (pixel-ICA) to analyze InfraRed Array Camera (IRAC) data, obtaining coherent results when applied to repeated transit observations previously debated in the literature. Here we introduce a variant to the pixel-ICA through the use of wavelet transform, wavelet pixel-ICA, which extends its applicability to low-signal-to-noise-ratio cases. We describe the method and discuss the results obtained over 12 eclipses of the exoplanet XO3b observed during the “Warm Spitzer” era in the 4.5 μm band. The final results are reported, in part, also in Ingalls et al. (2016), together with results obtained with other detrending methods, and over 10 synthetic eclipses that were analyzed for the “IRAC Data Challenge 2015.” Our results are consistent within 1σ with the ones reported in Wong et al. (2014) and with most of the results reported in Ingalls et al. (2016), which appeared on arXiv while this paper was under review. Based on many statistical tests discussed in Ingalls et al. (2016), the wavelet pixel-ICA method performs as well as or better than other state-of-art methods recently developed by other teams to analyze Spitzer/IRAC data, and, in particular, it appears to be the most repeatable and the most reliable, while reaching the photon noise limit, at least for the particular data set analyzed. Another strength of the ICA approach is its highest

  6. Legacy management: An old challenge with a new focus

    International Nuclear Information System (INIS)

    Gillogly, Mari; ); Sneve, Malgorzata; Smith, Graham

    2017-01-01

    The NEA Expert Group on Legacy Management (EGLM) aims to promote a practical and optimised approach for the regulatory supervision of nuclear legacy sites and installations. NEA member countries share their experiences and approaches on legacy management and have submitted case studies to the EGLM that illustrate the common challenges and approaches of many countries. The first report of the expert group will be based on these case studies and will be released in late 2017. A new, broader focus on decommissioning and legacy management issues within the NEA is expected to take shape in early 2018, carrying forward the mission to develop and promote a practical and optimised approach for the regulatory supervision of nuclear legacy sites and installations

  7. Galactic winds and the hubble sequence

    International Nuclear Information System (INIS)

    Bregman, J.N.

    1978-01-01

    The conditions for maintenance of supernova-driven galactic winds have been investigated to assess their role in the morphology of disk-bulge galaxies. A fluid mechanical model with gas and stars which includes galactic rotation has been used to investigate several classes of winds. It is found that many galaxies, once their initial gas is depleted, can maintain a wind throughout the entire galaxy, a conditon most easily satisfied by systems with a small bulge-to-disk ratio. If the ratio of supernova heating to total mass loss falls below a critical value that depends on galaxy type and mass, only a partial wind exterior to a critical surface can exist, with infall occurring at interior points. Galaxies in which only the bulge was depleted of gas may support a bulge wind that does not interact with the colder and denser gas in the disk.These results indicate that if SO galaxies are a transition class between elliptical and spiral galaxies, it is probably because early galactic winds, which may initially deplete a galaxy of gas, are more prevalent in SO than in spiral galaxies. However, if SO's form a parallel sequence with spirals, the initial gas-depletion mechanism must be independent of bulge-to-disk ratio. These results are not strongly influenced by altering the galactic mass model, including electron conduction in the flow equations, or adding massive halos

  8. Evolved stars in Galactic Plane surveys

    Science.gov (United States)

    Verbeek, Kars

    2013-09-01

    For the first time in history the entire Galactic Plane is digitally mapped from La Palma and Chile by the European Galactic Plane surveys EGAPS (UVEX, IPHAS and VPHAS+, see http://www.uvexsurvey.org http://www.iphas.org and http://www.vphasplus.org). The complete Galactic plane (3600 square degrees) is imaged in optical colours (U,g,r,i, H-alpha and HeI 5875) down to 21st magnitude using the INT and VST telescopes. This will eventually result into a multi-colour mosaic and a catalogue with more than a billion of stars. In this thesis the populations of evolved stars (white dwarfs, compact binaries and other UV-excess sources) in the data of the "UV-Excess Survey of the Northern Galactic Plane (UVEX)" are studied. From the first 211 square degrees of UVEX data, the bluest stars are automatically selected as UV-excess sources, spectroscopic follow-up of UV-excess objects is obtained, a DA white dwarfs space number density and birth rate is derived, and UV-excess sources with an infrared-excess are investigated. (see also Verbeek et al., 2012; Verbeek et al., 2013; Groot et al., 2009).

  9. Direct evidence for a massive galactic halo

    International Nuclear Information System (INIS)

    Hawkins, M.R.S.

    1983-01-01

    The discovery of a very distant galactic RR Lyrae star, R15 is reported. Spectroscopic observations of the object show that it has a high negative radial velocity, implying a lower limit to the mass of the galaxy of 1.4 x 10 12 Msun. (author)

  10. MODIFIED GRAVITY SPINS UP GALACTIC HALOS

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jounghun [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of); Zhao, Gong-Bo [National Astronomy Observatories, Chinese Academy of Science, Beijing 100012 (China); Li, Baojiu [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Koyama, Kazuya, E-mail: jounghun@astro.snu.ac.kr [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom)

    2013-01-20

    We investigate the effect of modified gravity on the specific angular momentum of galactic halos by analyzing the halo catalogs at z = 0 from high-resolution N-body simulations for a f(R) gravity model that meets the solar-system constraint. It is shown that the galactic halos in the f(R) gravity model tend to acquire significantly higher specific angular momentum than those in the standard {Lambda}CDM model. The largest difference in the specific angular momentum distribution between these two models occurs for the case of isolated galactic halos with mass less than 10{sup 11} h {sup -1} M {sub Sun }, which are likely least shielded by the chameleon screening mechanism. As the specific angular momentum of galactic halos is rather insensitive to other cosmological parameters, it can in principle be an independent discriminator of modified gravity. We speculate a possibility of using the relative abundance of low surface brightness galaxies (LSBGs) as a test of general relativity given that the formation of the LSBGs occurs in fast spinning dark halos.

  11. Star formation inside a galactic outflow.

    Science.gov (United States)

    Maiolino, R; Russell, H R; Fabian, A C; Carniani, S; Gallagher, R; Cazzoli, S; Arribas, S; Belfiore, F; Bellocchi, E; Colina, L; Cresci, G; Ishibashi, W; Marconi, A; Mannucci, F; Oliva, E; Sturm, E

    2017-04-13

    Recent observations have revealed massive galactic molecular outflows that may have the physical conditions (high gas densities) required to form stars. Indeed, several recent models predict that such massive outflows may ignite star formation within the outflow itself. This star-formation mode, in which stars form with high radial velocities, could contribute to the morphological evolution of galaxies, to the evolution in size and velocity dispersion of the spheroidal component of galaxies, and would contribute to the population of high-velocity stars, which could even escape the galaxy. Such star formation could provide in situ chemical enrichment of the circumgalactic and intergalactic medium (through supernova explosions of young stars on large orbits), and some models also predict it to contribute substantially to the star-formation rate observed in distant galaxies. Although there exists observational evidence for star formation triggered by outflows or jets into their host galaxy, as a consequence of gas compression, evidence for star formation occurring within galactic outflows is still missing. Here we report spectroscopic observations that unambiguously reveal star formation occurring in a galactic outflow at a redshift of 0.0448. The inferred star-formation rate in the outflow is larger than 15 solar masses per year. Star formation may also be occurring in other galactic outflows, but may have been missed by previous observations owing to the lack of adequate diagnostics.

  12. Scale Length of the Galactic Thin Disk

    Indian Academy of Sciences (India)

    tribpo

    the new value of hR. The model fit with data is not, however, completely satisfactory in J-KS, which might be improved by a slight change of SFR history in the model. One expects that the Galactic evolution parameters will be better known after the analysis of the Hipparcos and Tycho catalogues. The Besancon model is in a.

  13. Vulnerability of streams to legacy nitrate sources

    Science.gov (United States)

    Tesoriero, Anthony J.; Duff, John H.; Saad, David A.; Spahr, Norman E.; Wolock, David M.

    2013-01-01

    The influence of hydrogeologic setting on the susceptibility of streams to legacy nitrate was examined at seven study sites having a wide range of base flow index (BFI) values. BFI is the ratio of base flow to total streamflow volume. The portion of annual stream nitrate loads from base flow was strongly correlated with BFI. Furthermore, dissolved oxygen concentrations in streambed pore water were significantly higher in high BFI watersheds than in low BFI watersheds suggesting that geochemical conditions favor nitrate transport through the bed when BFI is high. Results from a groundwater-surface water interaction study at a high BFI watershed indicate that decades old nitrate-laden water is discharging to this stream. These findings indicate that high nitrate levels in this stream may be sustained for decades to come regardless of current practices. It is hypothesized that a first approximation of stream vulnerability to legacy nutrients may be made by geospatial analysis of watersheds with high nitrogen inputs and a strong connection to groundwater (e.g., high BFI).

  14. Legacy and Emerging Perfluoroalkyl Substances Are ...

    Science.gov (United States)

    Long-chain per- and polyfluoroalkyl substances (PFASs) are being replaced by short-chain PFASs and fluorinated alternatives. For ten legacy PFASs and seven recently discovered perfluoroalkyl ether carboxylic acids (PFECAs), we report (1) their occurrence in the Cape Fear River (CFR) watershed, (2) their fate in water treatment processes, and (3) their adsorbability on powdered activated carbon (PAC). In the headwater region of the CFR basin, PFECAs were not detected in raw water of a drinking water treatment plant (DWTP), but concentrations of legacy PFASs were high. The U.S. Environmental Protection Agency’s lifetime health advisory level (70 ng/L) for perfluorooctanesulfonic acid and perfluorooctanoic acid (PFOA) was exceeded on 57 of 127 sampling days. In raw water of a DWTP downstream of a PFAS manufacturer, the mean concentration of perfluoro-2-propoxypropanoic acid (PFPrOPrA), a replacement for PFOA, was 631 ng/L (n = 37). Six other PFECAs were detected, with three exhibiting chromatographic peak areas up to 15 times that of PFPrOPrA. At this DWTP, PFECA removal by coagulation, ozonation, biofiltration, and disinfection was negligible. The adsorbability of PFASs on PAC increased with increasing chain length. Replacing one CF2 group with an ether oxygen decreased the affinity of PFASs for PAC, while replacing additional CF2 groups did not lead to further affinity changes. The USEPA’s recently completed Unregulated Contaminant Monitoring Rule 3 (UCMR3) p

  15. The mycological legacy of Elias Magnus Fries.

    Science.gov (United States)

    Petersen, Ronald H; Knudsen, Henning

    2015-06-01

    The taxonomic concepts which originated with or were accepted by Elias Magnus Fries were presented during his lifetime in the printed word, illustrative depiction, and in collections of dried specimens. This body of work was welcomed by the mycological and botanical communities of his time: students and associates aided Fries and after his passing carried forward his taxonomic ideas. His legacy spawned a line of Swedish and Danish mycologists intent on perpetuating the Fries tradition: Hampus von Post, Lars Romell, Seth Lundell and John Axel Nannfeldt in Sweden; Emil Rostrup, Severin Petersen and Jakob Lange in Denmark. Volumes of color paintings and several exsiccati, most notably one edited by Lundell and Nannfeldt attached fungal portraits and preserved specimens (and often photographs) to Fries names. The result is a massive resource from which to harvest the name-concept relationship with clarity. In the 20th century, nomenclatural commissions legislated Fries's Systema and Elenchus as the "starting point" for names of most fungi, giving these books special recognition. The present paper attempts to trace Fries's legacy from his lifetime to the recent past.

  16. The impact of endorsing Spitzer's proposed criteria for PTSD in the forthcoming DSM-V on male and female Veterans.

    Science.gov (United States)

    Miller, Lyndsey N; Chard, Kathleen M; Schumm, Jeremiah A; O'Brien, Carol

    2011-06-01

    This study explored differences between Spitzer's proposed model of posttraumatic stress disorder (PTSD) and the current DSM-IV diagnostic classification scheme in 353 Veterans. The majority of Veterans (89%) diagnosed with PTSD as specified in the DSM-IV also met Spitzer's proposed criteria. Veterans who met both DSM-IV and Spitzer's proposed criteria had significantly higher Clinician Administered PTSD Scale severity scores than Veterans only meeting DSM-IV criteria. Logistic regression indicated that being African American and having no comorbid diagnosis of major depressive disorder or history of a substance use disorder were found to predict those Veterans who met current, but not proposed criteria. These findings have important implications regarding proposed changes to the diagnostic classification criteria for PTSD in the forthcoming DSM-V. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey. I. Sample Selection and Redshift Distribution

    Science.gov (United States)

    Perley, D. A.; Kruhler, T.; Schulze, S.; Postigo, A. De Ugarte; Hjorth, J.; Berger, E.; Cenko, S. B.; Chary, R.; Cucchiara, A.; Ellis, R.; hide

    2016-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey (SHOALS), a multi-observatory high redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst (GRB) hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host galaxy observational program, consisting of deep Spitzer/IRAC imaging of every field supplemented by similarly deep, multicolor optical/near-IR photometry, plus spectroscopy of events without preexisting redshifts. Our optimized selection cuts combined with host galaxy follow-up have so far enabled redshift measurements for 110 targets (92%) and placed upper limits on all but one of the remainder. About 20% of GRBs in the sample are heavily dust obscured, and at most 2% originate from z > 5.5. Using this sample, we estimate the redshift-dependent GRB rate density, showing it to peak at z approx. 2.5 and fall by at least an order of magnitude toward low (z = 0) redshift, while declining more gradually toward high (z approx. 7) redshift. This behavior is consistent with a progenitor whose formation efficiency varies modestly over cosmic history. Our survey will permit the most detailed examination to date of the connection between the GRB host population and general star-forming galaxies, directly measure evolution in the host population over cosmic time and discern its causes, and provide new constraints on the fraction of cosmic star formation occurring in undetectable galaxies at all redshifts.

  18. Albedo Corrections for High Albedo Near Earth Objects Observed With Spitzer

    Science.gov (United States)

    Gustafsson, Annika; Trilling, David E.; Mommert, Michael; Hora, Joseph L.

    2017-10-01

    Thermal infrared observations are the most effective way to measure asteroid diameter and albedo. Major surveys like NEOWISE and NEOSurvey return a small fraction of objects with albedo values higher than that believed to exist in the near-Earth object (NEO) population. About 10% of Spitzer-observed NEOs have nominal albedo solutions greater than 0.5. There are many possible causes for these unrealistically high albedos, including thermal lightcurves (leading to a mis-estimate of asteroid diameter) or inaccurate absolute visual magnitudes (either from poor photometry or lightcurve effects). We present here the results of a ground-based optical photometric study of 36 high albedo NEOs from NEOSurvey (Trilling et al. 2016) using measurements from the Discovery Channel Telescope. Our findings indicate that uncertainty in the diameter has the most impact on the derived albedo of our targets, while the uncertainty in the H-magnitude and slope parameter have smaller effects. We supply corrected albedos for our target list, as well as a systematic offset dependent on the solar phase angle of the object (Mommert el al. 2017). These corrected albedo values will help constrain the albedo range in the population to better reflect its physical characteristics. This work is based in part on the observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech.

  19. Spitzer IRAC mid-infrared photometry of 500-750 brown dwarf

    Energy Technology Data Exchange (ETDEWEB)

    Saumon, Didier [Los Alamos National Laboratory; Leggett, Sandy K [GEMINI OBSERVATORY; Albert, Loic [CFH TELESCOPE; Artigau, Etienne [U OF MONTREAL; Burningham, Ben [HERTFORDSHIRE U; Delfosse, Xavier [OBS. GRENOBLE; Delorme, Philippe [ST. ANDREWS U.; Forveille, Thierry [OBS. GRENOBLE; Lucas, Philip W [HERTFORDSHIRE U; Marley, Mark S [NASA AMES; Pinfield, David J [HERTFORDSHIRE U.; Reyle, Celine [OBS. BESANCON; Smart, Richard L [OSS. ASTRON, TORINO; Warren, Stephen J [IMPERIAL COLLEGE LONDON

    2010-10-26

    Mid-infrared data, including Spitzer warm-IRAC [3.6] and [4.5] photometry, is critical for understanding the cold population of brown dwarfs now being found, objects which have more in common with planets than stars. As effective temperature (T{sub eff}) drops from 800K to 400K, the fraction of flux emitted beyond 3 {mu}m increases rapidly, from about 40% to > 75%. This rapid increase makes a color like H-[4.5] a very sensitive temperature indicator, and it can be combined with a gravity- and metallicity-sensitive color like H-K to constrain all three of these fundamental properties, which in turn gives us mass and age for these slowly cooling objects. Determination of mid-infrared color trends also allows better exploitation of the WISE mission by the community. We use new Spitzer Cycle 6 IRAC photometry, together with published data, to present trends of color with type for L0 to T10 dwarfs. We also use the atmospheric and evolutionary models of Saumon and Marley to investigate the masses and ages of 13 very late-type T dwarfs, which have H-[4.5] > 3.2 and T{sub eff} {approx} 500K to 750K.

  20. Spitzer Observations of Dust Destruction in the Puppis A Supernova Remnant

    Science.gov (United States)

    Arendt, Richard G.; Dweek, Eli; Blair, William P.; Ghavamian, Parviz; Hwang, Una; Long, Knox X.; Petre, Robert; Rho, Jeonghee; Winkler, P. Frank

    2010-01-01

    The interaction of the Puppis A supernova remnant (SNR) with a neighboring molecular cloud provides a unique opportunity to measure the amount of grain destruction in an SNR shock. Spitzer Space Telescope MIPS imaging of the entire SNR at 24, 70, and 160 micrometers shows an extremely good correlation with X-ray emission, indicating that the SNR's IR radiation is dominated by the thermal emission of swept-up interstellar dust, collisionally heated by the hot shocked gas. Spitzer IRS spectral observations targeted both the Bright Eastern Knot (BEK) of the SNR where a small cloud has been engulfed by the supernova blast wave and outlying portions of the associated molecular cloud that are yet to be hit by the shock front. Modeling the spectra from both regions reveals the composition and the grain size distribution of the interstellar dust, both in front of and behind the SNR shock front. The comparison shows that the ubiquitous polycyclic aromatic hydrocarbons of the interstellar medium are destroyed within the BEK, along with nearly 25% of the mass of graphite and silicate dust grains.

  1. DUST EVOLUTION IN PROTOPLANETARY DISKS AROUND HERBIG Ae/Be STARS-THE SPITZER VIEW

    International Nuclear Information System (INIS)

    Juhasz, A.; Bouwman, J.; Henning, Th.; Acke, B.; Waters, L. B. F. M.; Van den Ancker, M. E.; Meeus, G.; Min, M.; Dominik, C.; Tielens, A. G. G. M.

    2010-01-01

    In this paper, we present mid-infrared spectra of a comprehensive set of Herbig Ae/Be stars observed with the Spitzer Space Telescope. The signal-to-noise ratio of these spectra is very high, ranging between about a hundred and several hundreds. During the analysis of these data we tested the validity of standardized protoplanetary dust models and studied grain growth and crystal formation. On the basis of the analyzed spectra, the major constituents of protoplanetary dust around Herbig Ae/Be stars are amorphous silicates with olivine and pyroxene stoichiometry, crystalline forsterite, and enstatite and silica. No other solid-state features, indicating other abundant dust species, are present in the Spitzer spectra. Deviations of the synthetic spectra from the observations are most likely related to grain shape effects and uncertainties in the iron content of the dust grains. Our analysis revealed that larger grains are more abundant in the disk atmosphere of flatter disks than in that of flared disks, indicating that grain growth and sedimentation decrease the disk flaring. We did not find, however, correlations between the value of crystallinity and any of the investigated system parameters. Our analysis shows that enstatite is more concentrated toward the warm inner disk than forsterite, in contrast to predictions of equilibrium condensation models. None of the three crystal formation mechanisms proposed so far can alone explain all our findings. It is very likely that all three play at least some role in the formation of crystalline silicates.

  2. A Spitzer Infrared Radius for the Transiting Extrasolar Planet HD 209458 b

    Science.gov (United States)

    Richardson, L. Jeremy; Harrington, Joseph; Seager, Sara; Deming, Drake

    2007-01-01

    We have measured the infrared transit of the extrasolar planet HD 209458 b using the Spitzer Space Telescope. We observed two primary eclipse events (one partial and one complete transit) using the 24 micrometer array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10-second integrations) of the planetary system, recorded before, during, and after transit. We perform optimal photometry on the images and use the local zodiacal light as a short-term flux reference. At this long wavelength, the transit curve has a simple box-like shape, allowing robust solutions for the stellar and planetary radii independent of stellar limb darkening, which is negligible at 24 micrometers. We derive a stellar radius of R(sub *) = 1.06 plus or minus 0.07 solar radius, a planetary radius of R(sub p) = 1.26 plus or minus 0.08 R(sub J), and a stellar mass of 1.17 solar mass. Within the errors, our results agree with the measurements at visible wavelengths. The 24 micrometer radius of the planet therefore does not differ significantly compared to the visible result. We point out the potential for deriving extrasolar transiting planet radii to high accuracy using transit photometry at slightly shorter IR wavelengths where greater photometric precision is possible.

  3. SPITZER OBSERVATIONS OF DUST DESTRUCTION IN THE PUPPIS A SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    Arendt, Richard G.; Dwek, Eli; Blair, William P.; Hwang, Una; Ghavamian, Parviz; Long, Knox S.; Petre, Robert; Rho, Jeonghee; Winkler, P. Frank

    2010-01-01

    The interaction of the Puppis A supernova remnant (SNR) with a neighboring molecular cloud provides a unique opportunity to measure the amount of grain destruction in an SNR shock. Spitzer Space Telescope MIPS imaging of the entire SNR at 24, 70, and 160 μm shows an extremely good correlation with X-ray emission, indicating that the SNR's IR radiation is dominated by the thermal emission of swept-up interstellar dust, collisionally heated by the hot shocked gas. Spitzer IRS spectral observations targeted both the Bright Eastern Knot (BEK) of the SNR where a small cloud has been engulfed by the supernova blast wave and outlying portions of the associated molecular cloud that are yet to be hit by the shock front. Modeling the spectra from both regions reveals the composition and the grain size distribution of the interstellar dust, both in front of and behind the SNR shock front. The comparison shows that the ubiquitous polycyclic aromatic hydrocarbons of the interstellar medium are destroyed within the BEK, along with nearly 25% of the mass of graphite and silicate dust grains.

  4. Sensitive Spitzer Photometry of Supermassive Black Holes at the Final Stage of Adolescence

    Science.gov (United States)

    Shemmer, Ohad; Netzer, Hagai; Mor, Rivay; Trakhtenbrot, Benny

    2011-05-01

    We propose to obtain sensitive Spitzer snapshot observations of a unique sample of 35 Sloan Digital Sky Survey quasars at redshift 4.8 for which we obtained reliable, Mg II-based determinations of the supermassive black hole (SMBH) mass and normalized accretion rate (L/L_Edd). These quasars appear to mark the final stage of SMBH `adolescence' in the history of the Universe as their SMBHs are significantly less massive and their L/L_Edd values are significantly higher with respect to their counterparts at lower redshifts. Our observations will provide both 1) deep coverage of the fields around these quasars which will be utilized as crucial priors for our approved Herschel/SPIRE observations of these sources, and 2) coverage of the rest-frame optical SEDs of these fast accreting quasars. The results will maximize our ability to measure the star-formation rate in the host galaxies of these quasars using Herschel. We will thus be able to investigate correlations between SMBH growth and star-forming activity in the early Universe. The Spitzer photometry will also provide invaluable information about the shape of the rest-frame optical continuum in these quasars which will be used to search for extreme disk properties that may be signatures of the remarkably high accretion rates in these sources.

  5. Olympic Health Legacy; Essentials for Lasting Development of Host City.

    Science.gov (United States)

    Lee, Young-Hee; Kim, Jung Moon

    2013-03-01

    The purpose of the Olympic Games should be to contribute to the social development by leaving behind economic, cultural and environmental legacies to the hosting region. While tangible examples such as venues are often recognized as representative legacies of the Olympics, intangible aspects such as the environment, culture, policy and human resources have been gaining in importance. The Olympic Games, at its most fundamental level, is a sporting event. Sports not only is closely related to the physical health, but is also instrumental to fostering mental health through inspiration. One of the most important sports legacies was the general change in the population's perception on sports and physical activities; due to such change, people were able to enjoy sports as part of healthy and active everyday life and benefit physically. However, compared to tangible legacies such as the facilities, social legacies such as the general health and their planning, execution and achievements are hard to monitor. Therefore, for the Olympics to leave behind socio-cultural legacies that contribute to the development of the hosting region, there must be a thorough business plan that takes into account region-specific purpose, and is divided into stages such as before, during and after the Games. Should the 2018 Winter Olympic Games hope to create continuing contribution to its hosting region, it must leave behind 'Health Legacies' that will enhance the happiness of the hosting region's population. To this end, establishment of region-specific purpose and systematic promotion of business via detailed analysis of precedents are a must. This article aim to review the health legacy endeavors of past host cities and suggest the appropriate forms of health legacy of 2018 Pyeongchang Winter Olympic and Paralympic Games.

  6. Cassini: The Journey and the Legacy

    KAUST Repository

    Porco, Carolyn

    2018-01-15

    An international mission to explore, in depth, the Saturnian system ヨthe planet Saturn and its magnetosphere, glorious rings, and many moons- begun over 27 years ago. After seven years of development, the Cassini spacecraft was launched in 1997, spent seven years trekking to Saturn, and finally entered Saturn orbit in the summer of 2004. In the course of its 13 years orbiting this ring world, Cassini returned over 450 thousand images, 635GB of data, and invaluable insights on the solar systemメs most splendid and scientifically rich planetary system. In this lecture, Carolyn Porco, the leader of the imaging science team on NASA\\'s Cassini mission, will delight her audience with a retrospective look at what has been learned from this profoundly successful mission and what its final legacy is likely to be.

  7. Peter Waterman and his scientific legacy

    Science.gov (United States)

    Mishchenko, Michael I.; Kahnert, Michael; Mackowski, Daniel W.; Wriedt, Thomas

    2013-01-01

    Peter C. Waterman, a giant figure in the theory of electromagnetic, acoustic, and elastic wave scattering, passed away on 3 June, 2012. In view of his fundamental contributions, which to a large degree have guided the progress of these disciplines over the past five decades and affected profoundly the multifaceted research published in the Journal of Quantitative Spectroscopy and Radiative Transfer (JQSRT), we felt that it would be appropriate to solicit papers for a special issue of JQSRT commemorating Peter Waterman's scientific legacy. This initiative was endorsed by the JQSRT management and has resulted in a representative collection of high-quality papers which have undergone the same peer scrutiny as any paper submitted to JQSRT.

  8. The Phenomenal Legacy of Rabindranath Tagore

    Directory of Open Access Journals (Sweden)

    Ketaki Kushari Dyson

    2010-12-01

    Full Text Available Belonging to a generation of Bengalis who received Tagore as an acknowledged classic of their tradition, I grew up reading his books, listening to his music, watching his dance-dramas, and writing poetry under the inspiration of his words. This youthful appreciation of Tagore eventually led to a deeper understanding of his stature as an artist and thinker, but it was only when I entered Tagore studies in a more formal manner that I realized how truly spectacular his achievements were from an international perspective. Tagore was fortunate in that his time, place, and circumstances allowed him to give a good run to the natural versatility and fecundity of his genius. He has thereby secured a rich and diverse legacy for us, which tends to mean different things to different groups of people.

  9. Could Freemium Models Work for Legacy Newspapers?

    DEFF Research Database (Denmark)

    Holm, Anna B.

    2016-01-01

    The newspaper industry has long been looking for sustainable business models for their digital editions. One of their popular choices is the freemium business model based on free and premium content with a paywall. However, freemium has not yet lived up to the expectation of the industry and has ...... not secured the revenues that industry players hoped for. This article discusses a number of the main principles of the freemium strategy and tactics, and highlights the critical points for legacy newspaper organisations.......The newspaper industry has long been looking for sustainable business models for their digital editions. One of their popular choices is the freemium business model based on free and premium content with a paywall. However, freemium has not yet lived up to the expectation of the industry and has...

  10. Managing a project's legacy: implications for organizations and project management

    Science.gov (United States)

    Cooper, Lynne P.; Hecht, Michael H.; Majchrzak, Ann

    2003-01-01

    Organizations that rely on projects to implement their products must find effective mechanisms for propagating lessons learned on one project throughout the organization. A broad view of what constitutes a project's 'legacy' is presented that includes not just the design products and leftover parts, but new processes, relationships, technology, skills, planning data, and performance metrics. Based on research evaluating knowledge reuse in innovative contexts, this paper presents an approach to project legacy management that focuses on collecting and using legacy knowledge to promote organizational learning and effective reuse, while addressing factors of post-project responsibility, information obsolescence, and the importance of ancillary contextual information. .

  11. The galactic X-ray sources

    International Nuclear Information System (INIS)

    Gursky, H.; Schreier, E.

    1975-01-01

    The current observational evidence on galactic X-ray sources is presented both from an astrophysical and astronomical point of view. The distributional properties of the sources, where they appear in the Galaxy, and certain average characteristics are discussed. In this way, certain properties of the X-ray sources can be deduced which are not apparent in the study of single objects. The properties of individual X-ray sources are then described. The hope is that more can be learnt about neutron stars and black holes, their physical properties, their origin and evolution, and their influence on other galactic phenomena. Thus attention is paid to those elements of data which appear to have the most bearing on these questions. (Auth.)

  12. Does the Galactic Bulge Have Fewer Planets?

    Science.gov (United States)

    Kohler, Susanna

    2016-12-01

    The Milky Ways dense central bulge is a very different environment than the surrounding galactic disk in which we live. Do the differences affect the ability of planets to form in the bulge?Exploring Galactic PlanetsSchematic illustrating how gravitational microlensing by an extrasolar planet works. [NASA]Planet formation is a complex process with many aspects that we dont yet understand. Do environmental properties like host star metallicity, the density of nearby stars, or the intensity of the ambient radiation field affect the ability of planets to form? To answer these questions, we will ultimately need to search for planets around stars in a large variety of different environments in our galaxy.One way to detect recently formed, distant planets is by gravitational microlensing. In this process, light from a distant source star is bent by a lens star that is briefly located between us and the source. As the Earth moves, this momentary alignment causes a blip in the sources light curve that we can detect and planets hosted by the lens star can cause an additional observable bump.Artists impression of the Milky Way galaxy. The central bulge is much denserthan the surroundingdisk. [ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt]Relative AbundancesMost source stars reside in the galactic bulge, so microlensing events can probe planetary systems at any distance between the Earth and the galactic bulge. This means that planet detections from microlensing could potentially be used to measure the relative abundances of exoplanets in different parts of our galaxy.A team of scientists led by Matthew Penny, a Sagan postdoctoral fellow at Ohio State University, set out to do just that. The group considered a sample of 31 exoplanetary systems detected by microlensing and asked the following question: are the planet abundances in the galactic bulge and the galactic disk the same?A Paucity of PlanetsTo answer this question, Penny and collaborators derived the expected

  13. Galactic signatures of decaying dark matter

    International Nuclear Information System (INIS)

    Zhang, Le; Sigl, Guenter

    2009-05-01

    If dark matter decays into electrons and positrons, it can affect Galactic radio emissions and the local cosmic ray fluxes. We propose a new, more general analysis of constraints on dark matter. The constraints can be obtained for any decaying dark matter model by convolving the specific dark matter decay spectrum with a response function. We derive this response function from full-sky radio surveys at 408 MHz, 1.42 GHz and 23 GHz, as well as from the positron flux recently reported by PAMELA. We discuss the influence of astrophysical uncertainties on the response function, such as from propagation and from the profiles of the dark matter and the Galactic magnetic field. As an application, we find that some widely used dark matter decay scenarios can be ruled out under modest assumptions. (orig.)

  14. Stability of BEC galactic dark matter halos

    Energy Technology Data Exchange (ETDEWEB)

    Guzmán, F.S.; Lora-Clavijo, F.D.; González-Avilés, J.J.; Rivera-Paleo, F.J., E-mail: guzman@ifm.umich.mx, E-mail: fadulora@ifm.umich.mx, E-mail: javiles@ifm.umich.mx, E-mail: friverap@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Cd. Universitaria, 58040 Morelia, Michoacán (Mexico)

    2013-09-01

    In this paper we show that spherically symmetric BEC dark matter halos, with the sin r/r density profile, that accurately fit galactic rotation curves and represent a potential solution to the cusp-core problem are unstable. We do this by introducing back the density profiles into the fully time-dependent Gross-Pitaevskii-Poisson system of equations. Using numerical methods to track the evolution of the system, we found that these galactic halos lose mass at an approximate rate of half of its mass in a time scale of dozens of Myr. We consider this time scale is enough as to consider these halos are unstable and unlikely to be formed. We provide some arguments to show that this behavior is general and discuss some other drawbacks of the model that restrict its viability.

  15. Brown dwarfs as dark galactic halos

    International Nuclear Information System (INIS)

    Adams, F.C.; Walker, T.P.

    1990-01-01

    The possibility that the dark matter in galactic halos can consist of brown dwarf stars is considered. The radiative signature for such halos consisting solely of brown dwarfs is calculated, and the allowed range of brown dwarf masses, the initial mass function (IMF), the stellar properties, and the density distribution of the galactic halo are discussed. The prediction emission from the halo is compared with existing observations. It is found that, for any IMF of brown dwarfs below the deuterium burning limit, brown dwarf halos are consistent with observations. Brown dwarf halos cannot, however, explain the recently observed near-IR background. It is shown that future satellite missions will either detect brown dwarf halos or place tight constraints on the allowed range of the IMF. 30 refs

  16. Gala: A Python package for galactic dynamics

    Science.gov (United States)

    Price-Whelan, Adrian M.

    2017-10-01

    Gala is an Astropy-affiliated Python package for galactic dynamics. Python enables wrapping low-level languages (e.g., C) for speed without losing flexibility or ease-of-use in the user-interface. The API for Gala was designed to provide a class-based and user-friendly interface to fast (C or Cython-optimized) implementations of common operations such as gravitational potential and force evaluation, orbit integration, dynamical transformations, and chaos indicators for nonlinear dynamics. Gala also relies heavily on and interfaces well with the implementations of physical units and astronomical coordinate systems in the Astropy package (astropy.units and astropy.coordinates). Gala was designed to be used by both astronomical researchers and by students in courses on gravitational dynamics or astronomy. It has already been used in a number of scientific publications and has also been used in graduate courses on Galactic dynamics to, e.g., provide interactive visualizations of textbook material.

  17. Does electromagnetic radiation accelerate galactic cosmic rays

    Science.gov (United States)

    Eichler, D.

    1977-01-01

    The 'reactor' theories of Tsytovich and collaborators (1973) of cosmic-ray acceleration by electromagnetic radiation are examined in the context of galactic cosmic rays. It is shown that any isotropic synchrotron or Compton reactors with reasonable astrophysical parameters can yield particles with a maximum relativistic factor of only about 10,000. If they are to produce particles with higher relativistic factors, the losses due to inverse Compton scattering of the electromagnetic radiation in them outweigh the acceleration, and this violates the assumptions of the theory. This is a critical restriction in the context of galactic cosmic rays, which have a power-law spectrum extending up to a relativistic factor of 1 million.

  18. Galactic signatures of decaying dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Le; Sigl, Guenter [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Redondo, Javier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-05-15

    If dark matter decays into electrons and positrons, it can affect Galactic radio emissions and the local cosmic ray fluxes. We propose a new, more general analysis of constraints on dark matter. The constraints can be obtained for any decaying dark matter model by convolving the specific dark matter decay spectrum with a response function. We derive this response function from full-sky radio surveys at 408 MHz, 1.42 GHz and 23 GHz, as well as from the positron flux recently reported by PAMELA. We discuss the influence of astrophysical uncertainties on the response function, such as from propagation and from the profiles of the dark matter and the Galactic magnetic field. As an application, we find that some widely used dark matter decay scenarios can be ruled out under modest assumptions. (orig.)

  19. Kinematics of HI near the galactic center

    International Nuclear Information System (INIS)

    Sinha, R.P.

    1979-01-01

    The results of a survey of 21-cm line emission in the Milky Way Galaxy from 338. 0 5 through 360 0 to 11 0 longitude and from -2 0 to +2 0 latitude are presented. The latitude coverage is complete over this range for a given longitude. Points are observed at an interval of 15 arcmin (0.7 beamwidth). The longitude coverage is complete between 1 = 357 0 and 1 = 3 0 . Outside this range points have been observed at intervals of 0. 0 5 in longitude. The symmetry properties of the distribution of HI in the region around the galactic center have been explored. Inside a radius of 1 kpc the HI appears to be distributed in the shape of an elongated non-circular slowly rotating disk which is inclined to the galactic equator. This disk is separate from the general galactic disk of HI. In the central disk the density of HI decreases steeply as the distance from the center increases. The density of HI in the annular space between the central disk and the general galactic disk is very low. The velocity dispersion of the HI distribution in the central elongated disk is of the order of 100 km/s. The isovelocity contours on the longitude-latitude plane of the HI associated with this elongated central disk have the characteristic shape such that the angle between the minor axis and the zero-Doppler velocity contour is different than zero. Such a phenomenon has been observed in the central regions of elliptical galaxies and has been attributed to the triaxial nature of the mass distribution

  20. The GOODS UV Legacy Fields: A Full Census of Faint Star-Forming Galaxies at z~0.5-2

    Science.gov (United States)

    Oesch, Pascal

    2014-10-01

    Deep HST imaging has shown that the overall star formation density and UV light density at z>3 is dominated by faint, blue galaxies. Remarkably, very little is known about the equivalent galaxy population at lower redshifts. Understanding how these galaxies evolve across the epoch of peak cosmic star-formation is key to a complete picture of galaxy evolution. While we and others have been making every effort to use existing UV imaging data, a large fraction of the prior data were taken without post-flash and are not photometric. We now propose to obtain a robust legacy dataset for a complete census of faint star-forming galaxies at z~0.5-2, akin to what is achieved at z>3, using the unique capabilities of the WFC3/UVIS camera to obtain very deep UV imaging to 27.5-28.0 mag over the CANDELS Deep fields in GOODS North and South. We directly sample the FUV at z>~0.5 and we make these prime legacy fields for JWST with unique and essential UV/blue HST coverage. Together with the exquisite ancillary multi-wavelength data at high spatial resolution from ACS and WFC3/IR our program will result in accurate photometric redshifts for very faint sources and will enable a wealth of research by the community. This includes tracing the evolution of the FUV luminosity function over the peak of the star formation rate density from z~3 down to z~0.5, measuring the physical properties of sub-L* galaxies, and characterizing resolved stellar populations to decipher the build-up of the Hubble sequence from sub-galactic clumps. The lack of a future UV space telescope makes the acquisition of such legacy data imperative for the JWST era and beyond.

  1. The Galactic Club or Galactic Cliques? Exploring the limits of interstellar hegemony and the Zoo Hypothesis

    Science.gov (United States)

    Forgan, Duncan H.

    2017-10-01

    The Zoo solution to Fermi's Paradox proposes that extraterrestrial intelligences (ETIs) have agreed to not contact the Earth. The strength of this solution depends on the ability for ETIs to come to agreement, and establish/police treaties as part of a so-called `Galactic Club'. These activities are principally limited by the causal connectivity of a civilization to its neighbours at its inception, i.e. whether it comes to prominence being aware of other ETIs and any treaties or agreements in place. If even one civilization is not causally connected to the other members of a treaty, then they are free to operate beyond it and contact the Earth if wished, which makes the Zoo solution `soft'. We should therefore consider how likely this scenario is, as this will give us a sense of the Zoo solution's softness, or general validity. We implement a simple toy model of ETIs arising in a Galactic Habitable Zone, and calculate the properties of the groups of culturally connected civilizations established therein. We show that for most choices of civilization parameters, the number of culturally connected groups is >1, meaning that the Galaxy is composed of multiple Galactic Cliques rather than a single Galactic Club. We find in our models for a single Galactic Club to establish interstellar hegemony, the number of civilizations must be relatively large, the mean civilization lifetime must be several millions of years, and the inter-arrival time between civilizations must be a few million years or less.

  2. Legacy Interventions With Patients with Co-Occurring Disorders: Legacy Definitions, Life Satisfaction, and Self-Efficacy.

    Science.gov (United States)

    Franklin, Felina C; Cheung, Monit

    2017-12-06

    Individuals with co-occurring disorders tend to avoid interaction with others. To instill hope, legacy intervention aims to highlight past experiences while managing life stressors for a positive outlook. Participants take part in legacy activities-crafting tangible projects and recording one's life events-in order to actualize a personal sense of legacy. This pre-posttest research tested whether legacy intervention in a partial hospital program (PHP) on reframing past experiences through creative activities could increase life satisfaction and self-efficacy among adults with co-occurring substance misuse and mental health symptoms. Eighty consented patients with co-occurring disorders were randomly assigned to two groups with 62 participants continuing: 37 in legacy intervention (LI) and 25 in partial hospital program only (PHP-only). LI participants were engaged in both PHP and legacy activities. Ten group sessions were held over the course of five weeks for cohorts of 10-15 adult patients in each intervention. Sense of legacy was measured to ensure that LI patients received the appropriate legacy dosage. With RANOVA analyses between and among three time points, life satisfaction was significantly higher in the LI group with group interaction effect over time. In terms of self-efficacy, both groups showed positive changes but no significant difference could be found between the two groups over time and the interaction (time X group) effect was not significant. The legacy definitions gathered from the LI group were consistent with existing literature and showed three additional themes: children's involvement, concreteness, and life continuation after death.

  3. Galactic civilizations - Population dynamics and interstellar diffusion

    Science.gov (United States)

    Newman, W. I.; Sagan, C.

    1981-01-01

    A model is developed of the interstellar diffusion of galactic civilizations which takes into account the population dynamics of such civilizations. The problem is formulated in terms of potential theory, with a family of nonlinear partial differential and difference equations specifying population growth and diffusion for an organism with advantageous genes that undergoes random dispersal while increasing in population locally, and a population at zero population growth. In the case of nonlinear diffusion with growth and saturation, it is found that the colonization wavefront from the nearest independently arisen galactic civilization can have reached the earth only if its lifetime exceeds 2.6 million years, or 20 million years if discretization can be neglected. For zero population growth, the corresponding lifetime is 13 billion years. It is concluded that the earth is uncolonized not because interstellar spacefaring civilizations are rare, but because there are too many worlds to be colonized in the plausible colonization lifetime of nearby civilizations, and that there exist no very old galactic civilizations with a consistent policy of the conquest of inhabited worlds.

  4. The galactic population of white dwarfs

    International Nuclear Information System (INIS)

    Napiwotzki, Ralf

    2009-01-01

    The contribution of white dwarfs of the different Galactic populations to the stellar content of our Galaxy is only poorly known. Some authors claim a vast population of halo white dwarfs, which would be in accordance with some investigations of the early phases of Galaxy formation claiming a top-heavy initial- mass- function. Here, I present a model of the population of white dwarfs in the Milky Way based on observations of the local white dwarf sample and a standard model of Galactic structure. This model will be used to estimate the space densities of thin disc, thick disc and halo white dwarfs and their contribution to the baryonic mass budget of the Milky Way. One result of this investigation is that white dwarfs of the halo population contribute a large fraction of the Galactic white dwarf number count, but they are not responsible for the lion's share of stellar mass in the Milky Way. Another important result is the substantial contribution of the - often neglected - population of thick disc white dwarfs. Misclassification of thick disc white dwarfs is responsible for overestimates of the halo population in previous investigations.

  5. Active galactic nucleus outflows in galaxy discs

    Science.gov (United States)

    Hartwig, Tilman; Volonteri, Marta; Dashyan, Gohar

    2018-05-01

    Galactic outflows, driven by active galactic nuclei (AGNs), play a crucial role in galaxy formation and in the self-regulated growth of supermassive black holes (BHs). AGN feedback couples to and affects gas, rather than stars, and in many, if not most, gas-rich galaxies cold gas is rotationally supported and settles in a disc. We present a 2D analytical model for AGN-driven outflows in a gaseous disc and demonstrate the main improvements, compared to existing 1D solutions. We find significant differences for the outflow dynamics and wind efficiency. The outflow is energy-driven due to inefficient cooling up to a certain AGN luminosity (˜1043 erg s-1 in our fiducial model), above which the outflow remains momentum-driven in the disc up to galactic scales. We reproduce results of 3D simulations that gas is preferentially ejected perpendicular to the disc and find that the fraction of ejected interstellar medium is lower than in 1D models. The recovery time of gas in the disc, defined as the free-fall time from the radius to which the AGN pushes the ISM at most, is remarkably short, of the order 1 Myr. This indicates that AGN-driven winds cannot suppress BH growth for long. Without the inclusion of supernova feedback, we find a scaling of the BH mass with the halo velocity dispersion of MBH ∝ σ4.8.

  6. A SPITZER SURVEY OF PROTOPLANETARY DISK DUST IN THE YOUNG SERPENS CLOUD : HOW DO DUST CHARACTERISTICS EVOLVE WITH TIME?

    NARCIS (Netherlands)

    Oliveira, Isa; Pontoppidan, Klaus M.; Merin, Bruno; van Dishoeck, Ewine F.; Lahuis, Fred; Geers, Vincent C.; Jorgensen, Jes K.; Olofsson, Johan; Augereau, Jean-Charles; Brown, Joanna M.

    2010-01-01

    We present Spitzer InfraRed Spectrograph (IRS) mid-infrared (5-35 mu m) spectra of a complete flux-limited sample (>= 3 mJy at 8 mu m) of young stellar object (YSO) candidates selected on the basis of their infrared colors in the Serpens Molecular Cloud. Spectra of 147 sources are presented and

  7. Investigating the Evolution of the Mass-Metallicity-SFR Relation at z<1.6 with Deep GALEX and Spitzer Imaging

    Science.gov (United States)

    Rigby, Jane

    UV and infrared imaging data are critical for determining stellar masses and the amount of star formation that is obscured by dust. We also plan to use a subsample of our galaxies, that have "gold standard" gas-phase metallicity measurements determined using the [OIII]4363 emission line, to test and improve existing "strong-line" metallicity calibrations. These calibrations were designed for galaxies in the local universe, and must be corrected for higher redshift since galaxies at this epoch have been shown to have different ISM's physical conditions (e.g., ionization parameter, density, abundance ratios). This effort will have a significant impact for future NASA's missions, such as JWST and WFIRST, as emission-line galaxies will be their primary galaxy sample. To select our sample of emission-line galaxies, we have used narrow-band imaging, which is highly effective (>80%) and benefits from several observational advantages. The deepest imaging, which enables studying low-mass galaxies, in the most number of NB filters, is in the Subaru Deep Field. Finally, we will publicly release our high-level science products, such as the UV-to-infrared spectral energy distribution and derived physical properties, to enable science beyond the scope of this proposal. The increase in accessibility will extend the legacy of deep GALEX and Spitzer imaging in the Subaru Deep Field.

  8. Methods for Finding Legacy Wells in Residential and Commercial Areas

    Energy Technology Data Exchange (ETDEWEB)

    Hammack, Richard [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Veloski, Garret [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2016-06-06

    The objective of this study was to locate legacy wells in Versailles Borough so that the Pennsylvania Department of Environmental Protection could mitigate dangerous CH4 concentrations in the community by venting or plugging leaking wells.

  9. Sport and exercise medicine and the Olympic health legacy

    Directory of Open Access Journals (Sweden)

    Tew Garry A

    2012-07-01

    Full Text Available Abstract London 2012 is the first Olympic and Paralympic Games to explicitly try and develop socioeconomic legacies for which success indicators are specified - the highest profile of which was to deliver a health legacy by getting two million more people more active by 2012. This editorial highlights how specialists in Sport and Exercise Medicine can contribute towards increasing physical activity participation in the UK, as well as how the National Centre for Sport and Exercise Medicine might be a useful vehicle for delivering an Olympic health legacy. Key challenges are also discussed such as acquisition of funding to support new physical activity initiatives, appropriate allocation of resources, and how to assess the impact of legacy initiatives.

  10. An assessment of mine legacies and how to prevent them

    DEFF Research Database (Denmark)

    Pacheco Cueva, Vladimir

    of AMD is felt well beyond the mining district and the costs of prevention and remediation were found to be significant. Apart from environmental legacies, the mine also left a number of socio-economic legacies including: limited access to non-polluted water that results in San Sebastian residents...... devoting a high proportion of their income in obtaining water, lost opportunities due to the cessation of mining, uncertain land tenure situation and increasing growth of ASGM activities that exacerbate already existing environmental pollution due to use of mercury. The study also found that the state......The study seeks to enrich the growing literature on mine legacies by examining a case study of a small abandoned mine in Latin America. Using a combination of Rapid Rural Appraisal and secondary source analysis, this study assessed some of the most damaging legacies of the San Sebastian mine...

  11. Legacy System Wrapping for Department of Defense Information System Modernization

    National Research Council Canada - National Science Library

    Jordan, Kathleen

    1995-01-01

    This document explains the activities, benefits, problems, and issues in using the object-oriented technique of software wrapping to support the migration from legacy information systems to modernized systems...

  12. SPITZER OBSERVATIONS OF WHITE DWARFS: THE MISSING PLANETARY DEBRIS AROUND DZ STARS

    International Nuclear Information System (INIS)

    Xu, S.; Jura, M.

    2012-01-01

    We report a Spitzer/Infrared Array Camera search for infrared excesses around white dwarfs, including 14 newly observed targets and 16 unpublished archived stars. We find a substantial infrared excess around two warm white dwarfs—J220934.84+122336.5 and WD 0843+516, the latter apparently being the hottest white dwarf known to display a close-in dust disk. Extending previous studies, we find that the fraction of white dwarfs with dust disks increases as the star's temperature increases; for stars cooler than 10,000 K, even the most heavily polluted ones do not have ∼1000 K dust. There is tentative evidence that the dust disk occurrence is correlated with the volatility of the accreted material. In the Appendix, we modify a previous analysis to clarify how Poynting-Robertson drag might play an important role in transferring materials from a dust disk into a white dwarf's atmosphere.

  13. Discovery of hyperluminous infrared galaxies using Spitzer and SHARC-II

    Science.gov (United States)

    Borys, C.; Barnard, V.; Bian, C.; Blain, A. W.; Brown, M. J. I.; Dey, A.; Dowell, C. D.; Frayer, D. T.; Higdon, J.; Higdon, S.; Jannuzi, B.; Le Floch, E.; Soifer, B. T.; Phillips, T. G.

    2005-01-01

    We have used observations taken as part of the Bootes Spitzer GTO program to pre-select high redshift luminous star-forming galaxy candidates. Subsequent ground-based sub-millimeter imaging with SHARC-II at the Caltech Submillimeter Observatory detected several objects, including one particularly exotic one: An extremely bright infrared galaxy with an apparent luminosity in excess of 1013.5Lsolar. It has a spectral energy distribution similar to that of Arp 220, though appears to be at a much higher redshift. Although lensing is one possible explanation, this object has helped refine the selection method, and hints at a way to pre-select similar objects using mid-IR silicate absorption features.

  14. Observations of Hot-Jupiter occultations combining Spitzer and Kepler photometry

    Directory of Open Access Journals (Sweden)

    Knutson H.

    2011-02-01

    Full Text Available We present the status of an ongoing program which aim at measuring occultations by their parent stars of transiting hot giant exoplanets discovered recently by Kepler. The observations are obtained in the near infrared with WarmSpitzer Space Telescope and at optical wavelengths by combining more than a year of Kepler photometry. The investigation consists of measuring the mid-occultation times and the relative occultation depths in each band-passes. Our measurements of occultations depths in the Kepler bandpass is turned into the determination of the optical geometric albedo Ag in this wavelength domain. The brightness temperatures of these planets are deduced from the infrared observations. We combine the optical and near infrared planetary emergent fluxes to obtain broad band emergent spectra of individual planet. We finally compare these spectra to hot Jupiter atmospheric models in order broadly distinguishing these atmospheres between different classes of models.

  15. Spitzer ’s View of the Candidate Cluster and Protocluster Catalog (CCPC)

    Energy Technology Data Exchange (ETDEWEB)

    Franck, J. R.; McGaugh, S. S. [Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106 (United States)

    2017-02-10

    The Candidate Cluster and Protocluster Catalog contains 218 galaxy overdensities composed of more than 2000 galaxies with spectroscopic redshifts spanning the first few Gyr after the Big Bang (2.0 ≤ z < 6.6). We use Spitzer archival data to track the underlying stellar mass of these overdense regions in various temporal cross sections by building rest-frame near-infrared luminosity functions (LFs) across the span of redshifts. This exercise maps the stellar growth of protocluster galaxies, as halos in the densest environments should be the most massive from hierarchical accretion. The characteristic apparent magnitude, m *( z ), is relatively flat from 2.0 ≤ z < 6.6, consistent with a passive evolution of an old stellar population. This trend maps smoothly to lower redshift results of cluster galaxies from other works. We find no difference in the LFs of galaxies in the field versus protoclusters at a given redshift apart from their density.

  16. Spitzer/JWST Cross Calibration: IRAC Observations of Potential Calibrators for JWST

    Science.gov (United States)

    Carey, Sean J.; Gordon, Karl D.; Lowrance, Patrick; Ingalls, James G.; Glaccum, William J.; Grillmair, Carl J.; E Krick, Jessica; Laine, Seppo J.; Fazio, Giovanni G.; Hora, Joseph L.; Bohlin, Ralph

    2017-06-01

    We present observations at 3.6 and 4.5 microns using IRAC on the Spitzer Space Telescope of a set of main sequence A stars and white dwarfs that are potential calibrators across the JWST instrument suite. The stars range from brightnesses of 4.4 to 15 mag in K band. The calibration observations use a similar redundancy to the observing strategy for the IRAC primary calibrators (Reach et al. 2005) and the photometry is obtained using identical methods and instrumental photometric corrections as those applied to the IRAC primary calibrators (Carey et al. 2009). The resulting photometry is then compared to the predictions based on spectra from the CALSPEC Calibration Database (http://www.stsci.edu/hst/observatory/crds/calspec.html) and the IRAC bandpasses. These observations are part of an ongoing collaboration between IPAC and STScI investigating absolute calibration in the infrared.

  17. Spitzer spectral line mapping of the HH211 outflow

    DEFF Research Database (Denmark)

    Dionatos, Odyssefs; Nisini, Brunella; Cabrit, Sylvie

    2010-01-01

    of emission line diagnostics and an existing grid of molecular shock models. The physical properties of the warm gas are compared against other molecular jet tracers and to the results of a similar study towards the L1448-C outflow. Results: We have detected and mapped the v=0-0 S(0) - S(7) H2 lines and fine...... compared to solar abundances by a factor ~10-50. Conclusions: Spitzer spectral mapping observations reveal for the first time a cool H$_2$ component towards the CO jet of HH211 consistent with the CO material being fully molecular and warm at ~ 300 K. The maps also reveal for the first time the existence...... uncertainties on jet speed and shock conditions are too large for a definite conclusion....

  18. Olympic Health Legacy; Essentials for Lasting Development of Host City

    Science.gov (United States)

    Lee, Young-Hee; Kim, Jung Moon

    2013-01-01

    The purpose of the Olympic Games should be to contribute to the social development by leaving behind economic, cultural and environmental legacies to the hosting region. While tangible examples such as venues are often recognized as representative legacies of the Olympics, intangible aspects such as the environment, culture, policy and human resources have been gaining in importance. The Olympic Games, at its most fundamental level, is a sporting event. Sports not only is closely related to the physical health, but is also instrumental to fostering mental health through inspiration. One of the most important sports legacies was the general change in the population’s perception on sports and physical activities; due to such change, people were able to enjoy sports as part of healthy and active everyday life and benefit physically. However, compared to tangible legacies such as the facilities, social legacies such as the general health and their planning, execution and achievements are hard to monitor. Therefore, for the Olympics to leave behind socio-cultural legacies that contribute to the development of the hosting region, there must be a thorough business plan that takes into account region-specific purpose, and is divided into stages such as before, during and after the Games. Should the 2018 Winter Olympic Games hope to create continuing contribution to its hosting region, it must leave behind ‘Health Legacies’ that will enhance the happiness of the hosting region’s population. To this end, establishment of region-specific purpose and systematic promotion of business via detailed analysis of precedents are a must. This article aim to review the health legacy endeavors of past host cities and suggest the appropriate forms of health legacy of 2018 Pyeongchang Winter Olympic and Paralympic Games. PMID:26064832

  19. A Spitzer five-band analysis of the Jupiter-sized planet TrES-1

    Energy Technology Data Exchange (ETDEWEB)

    Cubillos, Patricio; Harrington, Joseph; Foster, Andrew S. D.; Lust, Nate B.; Hardy, Ryan A.; Bowman, M. Oliver [Planetary Sciences Group, Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States); Madhusudhan, Nikku, E-mail: pcubillos@fulbrightmail.org [Department of Physics and Department of Astronomy, Yale University, New Haven, CT 06511 (United States)

    2014-12-10

    With an equilibrium temperature of 1200 K, TrES-1 is one of the coolest hot Jupiters observed by Spitzer. It was also the first planet discovered by any transit survey and one of the first exoplanets from which thermal emission was directly observed. We analyzed all Spitzer eclipse and transit data for TrES-1 and obtained its eclipse depths and brightness temperatures in the 3.6 μm (0.083% ± 0.024%, 1270 ± 110 K), 4.5 μm (0.094% ± 0.024%, 1126 ± 90 K), 5.8 μm (0.162% ± 0.042%, 1205 ± 130 K), 8.0 μm (0.213% ± 0.042%, 1190 ± 130 K), and 16 μm (0.33% ± 0.12%, 1270 ± 310 K) bands. The eclipse depths can be explained, within 1σ errors, by a standard atmospheric model with solar abundance composition in chemical equilibrium, with or without a thermal inversion. The combined analysis of the transit, eclipse, and radial-velocity ephemerides gives an eccentricity of e=0.033{sub −0.031}{sup +0.015}, consistent with a circular orbit. Since TrES-1's eclipses have low signal-to-noise ratios, we implemented optimal photometry and differential-evolution Markov Chain Monte Carlo (MCMC) algorithms in our Photometry for Orbits, Eclipses, and Transits pipeline. Benefits include higher photometric precision and ∼10 times faster MCMC convergence, with better exploration of the phase space and no manual parameter tuning.

  20. Brown dwarf distances and atmospheres: Spitzer Parallaxes and the Keck/NIRSPEC upgrade

    Science.gov (United States)

    Martin, Emily C.

    2018-01-01

    Advances in infrared technology have been essential towards improving our understanding of the solar neighborhood, revealing a large population of brown dwarfs, which span the mass regime between planets and stars. My thesis combines near-infrared (NIR) spectroscopic and astrometric analysis of nearby low-mass stars and brown dwarfs with instrumentation work to upgrade the NIRSPEC instrument for the Keck II Telescope. I will present results from a program using Spitzer/IRAC data to measure precise locations and distances to 22 of the coldest and closest brown dwarfs. These distances allow us to constrain absolute physical properties, such as mass, radius, and age, of free-floating planetary-mass objects through comparison to atmospheric and evolutionary models. NIR spectroscopy combined with the Spitzer photometry reveals a detailed look into the atmospheres of brown dwarfs and gaseous extrasolar planets. Additionally, I will discuss the improvements we are making to the NIRSPEC instrument at Keck. NIRSPEC is a NIR echelle spectrograph, capable of R~2000 and R~25,000 observations in the 1-5 μm range. As part of the upgrade, I performed detector characterization, optical design of a new slit-viewing camera, mechanical testing, and electronics design. NIRSPEC’s increased efficiency will allow us to obtain moderate- and high-resolution NIR spectra of objects up to a magnitude fainter than the current NIRSPEC design. Finally, I will demonstrate the utility of a NIR laser frequency comb as a high-resolution calibrator. This new technology will revolutionize precision radial velocity measurements in the coming decade.

  1. Spitzer and Chandra Observations of the Deep Impact Encounter with Comet 9P/Tempel 1

    Science.gov (United States)

    Lisse, C. M.; A'Hearn, M. F.; Belton, M. J. S.; Bodewits, D.; Christian, D. J.; VanCleve, J.; Combi, M.; Dennerl, K.; Farnham, T. L.; Fernandez, Y. R.; Groussin, O.; Hoekstra, R.; Makinen, T.; McFadden, L. A.; Meech, K. J.; Schultz, P.; Weaver, H.; Wolk, S.

    2005-12-01

    On July 4, 2005 NASA's discovery mission Deep Impact (hereafter DI) sent a 375 kg impactor into the nucleus of comet 9P/Tempel 1 at 10.2 km/s relative velocity (A'Hearn et al. 2005). In the IR, Spitzer observed the comet in the unique 5-38 μm spectral range provided by the IRS instrument, allowing direct determination of silicaceous dust, PAHs, carbonates, and aluminum and iron oxides/sulfides in the subsurface material. The Spitzer observations contrasted well with the 1-5 μm spectra obtained by the DI High Resolution Instrument's IR spectrometer and ground based measurements at 1-5 um from the Keck and IRTF observatories (Meech et al. 2005), enabling us to obtain full coverage of the comet's IR spectrum from 1.0 to 38 μm. In the x-ray, the DI experiment allowed for a controlled test of the charge exchange (CXE) emission mechanism that drives cometary x-ray emission (Lisse et al. 2001, Kharchenko and Dalgarno 2001, Krasnopolsky et al. 2002) using observations with the Chandra ACIS-S CCD. The Chandra spectra show a fresh amount of neutral material was injected into a finite volume of the extended atmosphere, or coma, of the comet. In the matter of minutes, this new material directly increased the emission measure for the comet by 30 production from other measurements. Additional contemporaneous measurements by the XMM and SWIFT low energy x-ray imagers provided complimentary lightcurve data points, providing a good long term estimate of the comet's gas emission before, during, and after the Deep Impact encounter. Over the longer term, the combined lightcurves showed evidence of multiple natural outbursts of neutral gas emission from the comet.

  2. Spitzer Observations of MAMBO Galaxies: Weeding Out Active Nuclei in Starbursting Protoellipticals

    Science.gov (United States)

    Ivison, R. J.; Greve, T. R.; Serjeant, S.; Bertoldi, F.; Egami, E.; Mortier, A. M. J.; Alonso-Herrero, A.; Barmby, P.; Bei, L.; Dole, H.; Engelbracht, C. W.; Fazio, G. G.; Frayer, D. T.; Gordon, K. D.; Hines, D. C.; Huang, J.-S.; Le Floc'h, E.; Misselt, K. A.; Miyazaki, S.; Morrison, J. E.; Papovich, C.; Pérez-González, P. G.; Rieke, M. J.; Rieke, G. H.; Rigby, J.; Rigopoulou, D.; Smail, I.; Wilson, G.; Willner, S. P.

    2004-09-01

    We present 3.6-24 μm Spitzer observations of an unbiased sample of nine luminous, dusty galaxies selected at 1200 μm by MAMBO on the IRAM 30 m telescope, a population akin to the well-known submillimeter or SCUBA galaxies (hereafter SMGs). Owing to the coarse resolution of submillimeter/millimeter cameras, SMGs have traditionally been difficult to identify at other wavelengths. We compare our multiwavelength catalogs to show that the overlap between 24 and 1200 μm must be close to complete at these flux levels. We find that all (4/4) of the most secure >=4 σ SMGs have >=4 σ counterparts at 1.4 GHz, while the fraction drops to 7/9 using all >=3 σ SMGs. We show that combining mid-infrared (MIR) and marginal (>=3 σ) radio detections provides plausible identifications in the remaining cases, enabling us to identify the complete sample. Accretion onto an obscured central engine is betrayed by the shape of the MIR continuum emission for several sources, confirming Spitzer's potential to weed out active galaxies. We demonstrate the power of an S24μm/S8μm versus S8μm/S4.5μm color-color plot as a diagnostic for this purpose. However, we conclude that the majority (~75%) of SMGs have rest-frame mid/far-IR spectral energy distributions commensurate with obscured starbursts. Sensitive 24 μm observations are clearly a useful route to identify and characterize reliable counterparts to high-redshift far-IR-bright galaxies, complementing what is possible via deep radio imaging.

  3. THE SPITZER INFRARED SPECTROGRAPH DEBRIS DISK CATALOG. II. SILICATE FEATURE ANALYSIS OF UNRESOLVED TARGETS

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Tushar [Department of Earth and Planetary Science, University of California Berkeley, Berkeley, CA 94720-4767 (United States); Chen, Christine H. [Space Telescope Science Institute, 3700 San Martin Drive Baltimore, MD 21218 (United States); Jang-Condell, Hannah [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Manoj, P. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India); Sargent, Benjamin A. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Watson, Dan M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Lisse, Carey M., E-mail: cchen@stsci.edu [Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States)

    2015-01-10

    During the Spitzer Space Telescope cryogenic mission, astronomers obtained Infrared Spectrograph (IRS) observations of hundreds of debris disk candidates that have been compiled in the Spitzer IRS Debris Disk Catalog. We have discovered 10 and/or 20 μm silicate emission features toward 120 targets in the catalog and modeled the IRS spectra of these sources, consistent with MIPS 70 μm observations, assuming that the grains are composed of silicates (olivine, pyroxene, forsterite, and enstatite) and are located either in a continuous disk with power-law size and surface density distributions or thin rings that are well-characterized using two separate dust grain temperatures. For systems better fit by the continuous disk model, we find that (1) the dust size distribution power-law index is consistent with that expected from a collisional cascade, q = 3.5-4.0, with a large number of values outside this range, and (2) the minimum grain size, a {sub min}, increases with stellar luminosity, L {sub *}, but the dependence of a {sub min} on L {sub *} is weaker than expected from radiation pressure alone. In addition, we also find that (3) the crystalline fraction of dust in debris disks evolves as a function of time with a large dispersion in crystalline fractions for stars of any particular stellar age or mass, (4) the disk inner edge is correlated with host star mass, and (5) there exists substantial variation in the properties of coeval disks in Sco-Cen, indicating that the observed variation is probably due to stochasticity and diversity in planet formation.

  4. FINDING η CAR ANALOGS IN NEARBY GALAXIES USING SPITZER. I. CANDIDATE SELECTION

    International Nuclear Information System (INIS)

    Khan, Rubab; Stanek, K. Z.; Kochanek, C. S.

    2013-01-01

    The late-stage evolution of the most massive stars such as η Carinae is controlled by the effects of mass loss, which may be dominated by poorly understood eruptive mass ejections. Understanding this population is challenging because no true analogs of η Car have been clearly identified in the Milky Way or other galaxies. We utilize Spitzer IRAC images of seven nearby (∼ 10 5 L ☉ in the IRAC bands (3.6 to 8.0 μm) and are not known to be background sources. Based on our estimates for the expected number of background sources, we expect that follow-up observations will show that most of these candidates are not dust enshrouded massive stars, with an expectation of only 6 ± 6 surviving candidates. Since we would detect true analogs of η Car for roughly 200 years post-eruption, this implies that the rate of eruptions like η Car is less than the core-collapse supernova rate. It is possible, however, that every M > 40 M ☉ star undergoes such eruptions given our initial results. In Paper II we will characterize the candidates through further analysis and follow-up observations, and there is no barrier to increasing the galaxy sample by an order of magnitude. The primary limitation of the present search is that Spitzer's resolution limits us to the shorter wavelength IRAC bands. With the James Webb Space Telescope, such surveys can be carried out at the far more optimal wavelengths of 10-30 μm, allowing identification of η Car analogs for millennia rather than centuries post-eruption.

  5. A deep Spitzer survey of circumstellar disks in the young double cluster, h and χ Persei

    Energy Technology Data Exchange (ETDEWEB)

    Cloutier, Ryan; Currie, Thayne; Jayawardhana, Ray [University of Toronto, 50 St. George Street, Toronto, ON, M5S 2J7 (Canada); Rieke, George H. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Kenyon, Scott J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02140 (United States); Balog, Zoltan, E-mail: cloutier@cita.utoronto.ca, E-mail: currie@astro.utoronto.ca, E-mail: grieke@as.arizona.edu, E-mail: skenyon@cfa.harvard.edu [Max Planck Institute for Astrophysics, Königstuhl 17, D-69117 Heidelberg (Germany)

    2014-12-01

    We analyze very deep Infrared Array Camera and Multiband Imaging Photometer for Spitzer (MIPS) photometry of ∼12, 500 members of the 14 Myr old Double Cluster, h and χ Persei, building upon our earlier, shallower Spitzer Cycle 1 studies. Numerous likely members show infrared (IR) excesses at 8 μm and 24 μm, indicative of circumstellar dust. The frequency of stars with 8 μm excess is at least 2% for our entire sample, slightly lower (higher) for B/A stars (later type, lower mass stars). Optical spectroscopy also identifies gas in about 2% of systems, but with no clear trend between the presence of dust and gas. Spectral energy distribution modeling of 18 sources with detections at optical wavelengths through MIPS 24 μm reveals a diverse set of disk evolutionary states, including a high fraction of transitional disks, though similar data for all disk-bearing members would provide constraints. Using Monte Carlo simulations, we combine our results with those for other young clusters to study the global evolution of dust/gas disks. For nominal cluster ages, the e-folding times (τ{sub 0}) for the frequency of warm dust and gas are 2.75 Myr and 1.75 Myr, respectively. Assuming a revised set of ages for some clusters, these timescales increase to 5.75 and 3.75 Myr, respectively, implying a significantly longer typical protoplanetary disk lifetime than previously thought. In both cases, the transitional disk duration, averaged over multiple evolutionary pathways, is ≈1 Myr. Finally, 24 μm excess frequencies for 4-6 M {sub ☉} stars appear lower than for 1-2.5 M {sub ☉} stars in other 10-30 Myr old clusters.

  6. Extragalactic and galactic sources: New evidence, new challenges, new opportunities

    Directory of Open Access Journals (Sweden)

    Kusenko Alexander

    2013-06-01

    Full Text Available Recent data bring in sharper focus the issue of relative contributions of galactic and extragalactic sources of ultrahigh-energy cosmic rays. On the one hand, there is some new evidence, from gamma-ray observations of blazars, that cosmic rays are, indeed, accelerated in AGNs. On the other hand, recent measurements of composition reported by Pierre Auger Observatory can be explained by a contribution of transient galactic sources, such as past GRBs and hypernovae, if nuclei accelerated in such events get trapped in the turbulent galactic magnetic fields. The likely contamination of UHECR data by the nuclei from past galactic stellar explosions creates new challenges for cosmic-ray astronomy. At the same time, it creates new opportunities for reconstructing galactic magnetic fields, understanding the history of transient galactic phenomena, and for using gamma rays to identify astrophysical nuclear accelerators outside Milky Way.

  7. Possible existence of wormholes in the galactic halo region

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, Farook [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); Kuhfittig, P.K.F. [Milwaukee School of Engineering, Department of Mathematics, Milwaukee, WI (United States); Ray, Saibal [Government College of Engineering and Ceramic Technology, Department of Physics, Kolkata, West Bengal (India); Islam, Nasarul [Danga High Madrasah, Department of Mathematics, Kolkata, West Bengal (India)

    2014-02-15

    Two observational results, the density profile from simulations performed in the ΛCDM scenario and the observed flat galactic rotation curves, are taken as input with the aim of showing that the galactic halo possesses some of the characteristics needed to support traversable wormholes. This result should be sufficient to provide an incentive for scientists to seek observational evidence for wormholes in the galactic halo region. (orig.)

  8. Unusual Metals in Galactic Center Stars

    Science.gov (United States)

    Hensley, Kerry

    2018-03-01

    Far from the galactic suburbs where the Sun resides, a cluster of stars in the nucleus of the Milky Way orbits a supermassive black hole. Can chemical abundance measurements help us understand the formation history of the galactic center nuclear star cluster?Studying Stellar PopulationsMetallicity distributions for stars in the inner two degrees of the Milky Way (blue) and the central parsec (orange). [Do et al. 2018]While many galaxies host nuclear star clusters, most are too distant for us to study in detail; only in the Milky Way can we resolve individual stars within one parsec of a supermassive black hole. The nucleus of our galaxy is an exotic and dangerous place, and its not yet clear how these stars came to be where they are were they siphoned off from other parts of the galaxy, or did they form in place, in an environment rocked by tidal forces?Studying the chemical abundances of stars provides a way to separate distinct stellar populations and discern when and where these stars formed. Previous studies using medium-resolution spectroscopy have revealed that many stars within the central parsec of our galaxy have very high metallicities possibly higher than any other region of the Milky Way. Can high-resolution spectroscopy tell us more about this unusual population of stars?Spectral Lines on DisplayTuan Do (University of California, Los Angeles, Galactic Center Group) and collaborators performed high-resolution spectroscopic observations of two late-type giant starslocated half a parsec from the Milky Ways supermassive black hole.Comparison of the observed spectra of the two galactic center stars (black) with synthetic spectra with low (blue) and high (orange) [Sc/Fe] values. Click to enlarge. [Do et al. 2018]In order to constrain the metallicities of these stars, Do and collaborators compared the observed spectra to a grid of synthetic spectra and used a spectral synthesis technique to determine the abundances of individual elements. They found that

  9. John Napier life, logarithms, and legacy

    CERN Document Server

    Havil, Julian

    2014-01-01

    John Napier (1550–1617) is celebrated today as the man who invented logarithms—an enormous intellectual achievement that would soon lead to the development of their mechanical equivalent in the slide rule: the two would serve humanity as the principal means of calculation until the mid-1970s. Yet, despite Napier’s pioneering efforts, his life and work have not attracted detailed modern scrutiny. John Napier is the first contemporary biography to take an in-depth look at the multiple facets of Napier’s story: his privileged position as the eighth Laird of Merchiston and the son of influential Scottish landowners; his reputation as a magician who dabbled in alchemy; his interest in agriculture; his involvement with a notorious outlaw; his staunch anti-Catholic beliefs; his interactions with such peers as Henry Briggs, Johannes Kepler, and Tycho Brahe; and, most notably, his estimable mathematical legacy. Julian Havil explores Napier’s original development of logarithms, the motivations for his approa...

  10. Latin America: Essays Interpretating Colonial Legacy

    Directory of Open Access Journals (Sweden)

    María Pia López

    2013-12-01

    Full Text Available A large part of the Latin–American literature of the 19th and 20th century tried to deal with the national question intertwining different dimensions: the weight of colonial legacy, the cultural peculiarity of the nation and the inner relations between social classes and ethnic groups. Thinking the nation implied, in any case, to think the difference and the conflict with others, as well as the inner conflict and the logic of local colonialism. Analyzing some of these essays that played a central role in such process of recasting the origin of the nation, the author moves around three main axes: the formulation of dualist writings (colonial/national; white /indigenous; civilization/wilderness, the issue of language (the language inherited from the colonial experience versus the multilingual nature of indigenous Latin American societies, and the hypothesis about the birth of the nation – appointed to different groups – and its normal functioning as legitimization of the order sprung from independences.

  11. Electrical distribution grids: from legacy to innovation

    International Nuclear Information System (INIS)

    Hadjsaid, N.; Sabonnadiere, J.C.; Angelier, J.P.

    2010-01-01

    The electrical distribution networks in general and distributed generation in particular are undergoing tremendous technological, economic and conceptual changes. Indeed, with the establishment of Distribution System Operators (DSOs), the environmental concerns of our modern societies, the needs of security and quality of supply and the emergence of new services related to the 'active energy customer' character have particularly highlighted the potential for innovation and development of distribution networks. Distribution networks are of particular importance because of their close link with the end user, their interface with distributed generation and their ability to facilitate and integrate new applications and services such as plug-in electric and hybrid vehicles or smart meters. On the other hand, they represent a large infrastructure that has become complex to manage with the emergence of this new energy paradigm. However, this strategic legacy is aging and the quality of supply, after years of improvement, begins to deteriorate again. It is therefore essential to increase investment in these assets at all levels whether in innovation, expansion or renovation to prepare the smarter grid of the future. (authors)

  12. Russian Planetary Exploration History, Development, Legacy, Prospects

    CERN Document Server

    Harvey, Brian

    2007-01-01

    Russia’s accomplishments in planetary space exploration were not achieved easily. Formerly, the USSR experienced frustration in trying to tame unreliable Molniya and Proton upper stages and in tracking spacecraft over long distances. This book will assess the scientific haul of data from the Venus and Mars missions and look at the engineering approaches. The USSR developed several generations of planetary probes: from MV and Zond to the Phobos type. The engineering techniques used and the science packages are examined, as well as the nature of the difficulties encountered which ruined several missions. The programme’s scientific and engineering legacy is also addressed, as well as its role within the Soviet space programme as a whole. Brian Harvey concludes by looking forward to future Russian planetary exploration (e.g Phobos Grunt sample return mission). Several plans have been considered and may, with a restoration of funding, come to fruition. Soviet studies of deep space and Mars missions (e.g. TMK, ...

  13. The History and Legacy of BATSE

    Science.gov (United States)

    Fishman, Gerald J.

    2012-01-01

    The BATSE experiment on the Compton Gamma-ray Observatory was the first large detector system specifically designed for the study of gamma-ray bursts. The eight large-area detectors allowed full-sky coverage and were optimized to operate in the energy region of the peak emission of most GRBs. BATSE provided detailed observations of the temporal and spectral characteristics of large samples of GRBs, and it was the first experiment to provide rapid notifications of the coarse location of many them. It also provided strong evidence for the cosmological distances to GRBs through the observation of the sky distribution and intensity distribution of numerous GRBs. The large number of GRBs observed with the high- sensitivity BATSE detectors continues to provide a database of GRB spectral and temporal properties in the primary energy range of GRB emission that will likely not be exceeded for at least another decade. The origin and development of the BATSE experiment, some highlights from the mission and its continuing legacy are described in this paper.

  14. The intangible legacy of the Indonesian Bajo

    Directory of Open Access Journals (Sweden)

    Chandra Nuraini

    2016-05-01

    Full Text Available The Sama-Bajau, or Bajo diaspora, extends from the southern Philippines and Sabah (Malaysian Borneo to the eastern part of Indonesia. The Indonesian Bajo, now scattered along the coasts of Sulawesi (Celebes and East Kalimantan, the Eastern Lesser Sunda Islands and Maluku, were once mostly nomadic fishermen of the sea or ocean freight carriers. Today, the Bajo are almost all fishermen and settled. Their former and present ways of life made them favour intangible forms of culture: it is impossible to transport bulky artefacts when moving frequently by boat, or when living in stilt houses, very close to the sea or on a reef. It is therefore an intangible legacy that is the essence of the Bajo’s culture. Sandro healers have a vast range of expertise that allows them to protect and heal people when they suffer from natural or supernatural diseases. On the other hand, music and especially oral literature are very rich. In addition to song and the pantun poetry contests, the most prestigious genre is the iko-iko, long epic songs that the Bajo consider to be historical rather than fictional narratives. The Bajo’s intangible heritage is fragile, since it is based on oral transmission. In this article, I give a description of this heritage, dividing it into two areas: the knowledge that allows them to “protect and heal” on the one hand, and to “distract and relax”, on the other.

  15. Hubble Legacy Archive And The Public

    Science.gov (United States)

    Harris, Jessica; Whitmore, B.; Eisenhamer, B.; Bishop, M.; Knisely, L.

    2012-01-01

    The Hubble Legacy Archive (HLA) at the Space Telescope Science Institute (STScI) hosts the Image of the Month (IOTM) Series. The HLA is a joint project of STScI, the Space Telescope European Coordinating Facility (ST-ECF), and the Canadian Astronomy Data Centre (CADC). The HLA is designed optimize science from the Hubble Space Telescope by providing online enhanced Hubble products and advanced browsing capabilities. The IOTM's are created for astronomers and the public to highlight various features within HLA, such as the "Interactive Display", "Footprint” and "Inventory” features to name a few. We have been working with the Office of Public Outreach (OPO) to create a standards based educational module for middle school to high school students of the IOTM: Rings and the Moons of Uranus. The set of Uranus activities are highlighted by a movie that displays the orbit of five of Uranus’ largest satellites. We made the movie based on eight visits of Uranus from 2000-06-16 to 2000-06-18, using the PC chip on the Wide Field Planetary Camera 2 (WFPC2) and filter F850LP (proposal ID: 8680). Students will be engaged in activities that will allow them to "discover” the rings and satellites around Uranus, calculate the orbit of the satellites, and introduces students to analyze real data from Hubble.

  16. Corruption in Mexico: A Historical Legacy

    Directory of Open Access Journals (Sweden)

    Nubia Nieto

    2014-06-01

    Full Text Available Among the many consequences of colonialism that are still present in postcolonial societies are corruption and the lack of strong institutions to fight against this phenomenon. What used to be unequal power relations between the colonizers and the colonies have been replaced by the dominance of the local elites over ordinary citizens, who have practically given the former a lot of leeway to commit acts of corruption with a sense of impunity and without regard for accountability. One case in point is Mexico which, in recent times, has made international news headlines because of incidences of drug trafficking, violence, and corruption in the country. This article delineates the historical relationship between corruption and colonialism, and how these forces have shaped Mexican culture. The discussion tackles the presence of corruption since the colonial times to the present. Specif ically, it starts with an analysis of the role of colonialism in the incidence of corruption. Secondly, it describes the discrepancy between the law and its application, from the arrival of the Spanish colonizers to the present. Finally, it examines the cultural, educational, and social challenges that should be addressed in order to surmount the colonial legacies that breed corruption.

  17. Millisecond Pulsars and the Galactic Center Excess

    Science.gov (United States)

    Gonthier, Peter L.; Koh, Yew-Meng; Kust Harding, Alice; Ferrara, Elizabeth C.

    2017-08-01

    Various groups including the Fermi team have confirmed the spectrum of the gamma- ray excess in the Galactic Center (GCE). While some authors interpret the GCE as evidence for the annihilation of dark matter (DM), others have pointed out that the GCE spectrum is nearly identical to the average spectrum of Fermi millisecond pul- sars (MSP). Assuming the Galactic Center (GC) is populated by a yet unobserved source of MSPs that has similar properties to that of MSPs in the Galactic Disk (GD), we present results of a population synthesis of MSPs from the GC. We establish parameters of various models implemented in the simulation code by matching characteristics of 54 detected Fermi MSPs in the first point source catalog and 92 detected radio MSPs in a select group of thirteen radio surveys and targeting a birth rate of 45 MSPs per mega-year. As a check of our simulation, we find excellent agreement with the estimated numbers of MSPs in eight globular clusters. In order to reproduce the gamma-ray spectrum of the GCE, we need to populate the GC with 10,000 MSPs having a Navarro-Frenk-White distribution suggested by the halo density of DM. It may be possible for Fermi to detect some of these MSPs in the near future; the simulation also predicts that many GC MSPs have radio fluxes S1400above 10 �μJy observable by future pointed radio observations. We express our gratitude for the generous support of the National Science Foundation (RUI: AST-1009731), Fermi Guest Investigator Program and the NASA Astrophysics Theory and Fundamental Program (NNX09AQ71G).

  18. Study of galactic light, extragalactic light, and galactic structure using pioneer 10 observations of background starlight

    International Nuclear Information System (INIS)

    Toller, G.N.

    1981-01-01

    An observational and theoretical study of the diffuse astronomical background sky brightness (background starlight) is carried out. The brightness is determined over 95% of the sky using Pioneer 10 photometric measurements in sky regions where the zodiacal light is negligible (heliocentric distances approx. greater than or equal to 3. A.U.). Brightness levels are presented at blue (3950 to 4850 A) and red (5900 to 6800 A) wavelengths. The B-R color index distribution is established over the celestial sphere. Pioneer 10 results are compared with previous star count and ground based photometric studies to separate background starlight into its constituent parts: integrated starlight, diffuse galactic light (DGL), and cosmic light. Significant errors are found in published star count results at low galactic latitudes. The galactic latitude (b'') and longitude (1'') dependences of integrated starlight and the variation of DGL with b'' are determined. An upper limit of 3.9 S 10 (V)/sub G2V/ at the 90% confidence level is deduced for the cosmic light brightness at blue wavelengths near the galactic poles. The integrated light from discrete galaxies adequately explains this component of the background starlight

  19. THE SWIFT GRB HOST GALAXY LEGACY SURVEY. II. REST-FRAME NEAR-IR LUMINOSITY DISTRIBUTION AND EVIDENCE FOR A NEAR-SOLAR METALLICITY THRESHOLD

    Energy Technology Data Exchange (ETDEWEB)

    Perley, D. A. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd., Pasadena, CA 91125 (United States); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Hjorth, J.; Fynbo, J. P. U.; Krühler, T. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 København Ø (Denmark); Laskar, T.; Berger, E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chary, R. [US Planck Data Center, MS220-6, Pasadena, CA 91125 (United States); Postigo, A. de Ugarte [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Levan, A. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Michałowski, M. J. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Schulze, S., E-mail: dperley@dark-cosmology.dk [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, 7820436 Macul, Santiago 22 (Chile)

    2016-01-20

    We present rest-frame near-IR (NIR) luminosities and stellar masses for a large and uniformly selected population of gamma-ray burst (GRB) host galaxies using deep Spitzer Space Telescope imaging of 119 targets from the Swift GRB Host Galaxy Legacy Survey spanning 0.03 < z < 6.3, and we determine the effects of galaxy evolution and chemical enrichment on the mass distribution of the GRB host population across cosmic history. We find a rapid increase in the characteristic NIR host luminosity between z ∼ 0.5 and z ∼ 1.5, but little variation between z ∼ 1.5 and z ∼ 5. Dust-obscured GRBs dominate the massive host population but are only rarely seen associated with low-mass hosts, indicating that massive star-forming galaxies are universally and (to some extent) homogeneously dusty at high redshift while low-mass star-forming galaxies retain little dust in their interstellar medium. Comparing our luminosity distributions with field surveys and measurements of the high-z mass–metallicity relation, our results have good consistency with a model in which the GRB rate per unit star formation is constant in galaxies with gas-phase metallicity below approximately the solar value but heavily suppressed in more metal-rich environments. This model also naturally explains the previously reported “excess” in the GRB rate beyond z ≳ 2; metals stifle GRB production in most galaxies at z < 1.5 but have only minor impact at higher redshifts. The metallicity threshold we infer is much higher than predicted by single-star models and favors a binary progenitor. Our observations also constrain the fraction of cosmic star formation in low-mass galaxies undetectable to Spitzer to be small at z < 4.

  20. THE MERGER HISTORY, ACTIVE GALACTIC NUCLEUS, AND DWARF GALAXIES OF HICKSON COMPACT GROUP 59

    Energy Technology Data Exchange (ETDEWEB)

    Konstantopoulos, I. S.; Charlton, J. C.; Brandt, W. N.; Eracleous, M.; Gronwall, C. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Gallagher, S. C.; Fedotov, K.; Hill, A. R. [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada); Durrell, P. R. [Department of Physics and Astronomy, Youngstown State University, Youngstown, OH 44555 (United States); Tzanavaris, P.; Hornschemeier, A. E. [Laboratory for X-ray Astrophysics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Zabludoff, A. I. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Maier, M. L. [Gemini Observatory, Casilla 603, Colina el Pino S/N, La Serena (Chile); Elmegreen, D. M. [Department of Physics and Astronomy, Vassar College, Poughkeepsie, NY 12604 (United States); Johnson, K. E.; Walker, L. M. [Department of Astronomy, University of Virginia, P. O. Box 400325, Charlottesville, VA 22904 (United States); Maybhate, A. [Space Telescope Science Institute, Baltimore, MD (United States); English, J. [University of Manitoba, Winnipeg, MN (Canada); Mulchaey, J. S., E-mail: iraklis@astro.psu.edu [Carnegie Observatories, Pasadena, CA 91101 (United States)

    2012-01-20

    Compact group galaxies often appear unaffected by their unusually dense environment. Closer examination can, however, reveal the subtle, cumulative effects of multiple galaxy interactions. Hickson Compact Group (HCG) 59 is an excellent example of this situation. We present a photometric study of this group in the optical (Hubble Space Telescope), infrared (Spitzer), and X-ray (Chandra) regimes aimed at characterizing the star formation and nuclear activity in its constituent galaxies and intra-group medium. We associate five dwarf galaxies with the group and update the velocity dispersion, leading to an increase in the dynamical mass of the group of up to a factor of 10 (to 2.8 Multiplication-Sign 10{sup 13} M{sub Sun }), and a subsequent revision of its evolutionary stage. Star formation is proceeding at a level consistent with the morphological types of the four main galaxies, of which two are star-forming and the other are two quiescent. Unlike in some other compact groups, star-forming complexes across HCG 59 closely follow mass-radius scaling relations typical of nearby galaxies. In contrast, the ancient globular cluster populations in galaxies HCG 59A and B show intriguing irregularities, and two extragalactic H II regions are found just west of B. We age-date a faint stellar stream in the intra-group medium at {approx}1 Gyr to examine recent interactions. We detect a likely low-luminosity active galactic nucleus in HCG 59A by its {approx}10{sup 40} erg s{sup -1} X-ray emission; the active nucleus rather than star formation can account for the UV+IR spectral energy distribution. We discuss the implications of our findings in the context of galaxy evolution in dense environments.

  1. Galactic orbital motions of star clusters: static versus semicosmological time-dependent Galactic potentials

    Science.gov (United States)

    Haghi, Hosein; Zonoozi, Akram Hasani; Taghavi, Saeed

    2015-07-01

    In order to understand the orbital history of Galactic halo objects, such as globular clusters, authors usually assume a static potential for our Galaxy with parameters that appear at the present day. According to the standard paradigm of galaxy formation, galaxies grow through a continuous accretion of fresh gas and a hierarchical merging with smaller galaxies from high redshift to the present day. This implies that the mass and size of disc, bulge, and halo change with time. We investigate the effect of assuming a live Galactic potential on the orbital history of halo objects and its consequences on their internal evolution. We numerically integrate backwards the equations of motion of different test objects located in different Galactocentric distances in both static and time-dependent Galactic potentials in order to see if it is possible to discriminate between them. We show that in a live potential, the birth of the objects, 13 Gyr ago, would have occurred at significantly larger Galactocentric distances, compared to the objects orbiting in a static potential. Based on the direct N-body calculations of star clusters carried out with collisional N-body code, NBODY6, we also discuss the consequences of the time-dependence of a Galactic potential on the early- and long-term evolution of star clusters in a simple way, by comparing the evolution of two star clusters embedded in galactic models, which represent the galaxy at present and 12 Gyr ago, respectively. We show that assuming a static potential over a Hubble time for our Galaxy as it is often done, leads to an enhancement of mass-loss, an overestimation of the dissolution rates of globular clusters, an underestimation of the final size of star clusters, and a shallower stellar mass function.

  2. Planck 2013 results. XIII. Galactic CO emission

    CERN Document Server

    Ade, P.A.R.; Alves, M.I.R.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Battaner, E.; Benabed, K.; Benoit, A.; Benoit-Levy, A.; Bernard, J. -P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J.J.; Bonaldi, A.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R.C.; Cardoso, J. -F.; Catalano, A.; Chamballu, A.; Chary, R. -R.; Chen, X.; Chiang, L. -Y; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J. -M.; Dempsey, J.T.; Desert, F. -X.; Dickinson, C.; Diego, J.M.; Dole, H.; Donzelli, S.; Dore, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enblin, T.A.; Eriksen, H.K.; Falgarone, E.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Fukui, Y.; Galeotta, S.; Ganga, K.; Giard, M.; Giraud-Heraud, Y.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Handa, T.; Hansen, F.K.; Hanson, D.; Harrison, D.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hily-Blant, P.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Hurier, G.; Jaffe, T.R.; Jaffe, A.H.; Jewell, J.; Jones, W.C.; Juvela, M.; Keihanen, E.; Keskitalo, R.; Kisner, T.S.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lahteenmaki, A.; Lamarre, J. -M.; Lasenby, A.; Laureijs, R.J.; Lawrence, C.R.; Leonardi, R.; Leon-Tavares, J.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Maffei, B.; Mandolesi, N.; Maris, M.; Marshall, D.J.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McGehee, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschenes, M. -A.; Moneti, A.; Montier, L.; Moore, T.J.T.; Morgante, G.; Morino, J.; Mortlock, D.; Munshi, D.; Nakajima, T.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Okuda, T.; Osborne, S.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G.W.; Preezeau, G.; Prunet, S.; Puget, J. -L.; Rachen, J.P.; Reach, W.T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rubino-Martin, J.A.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Spencer, L.D.; Starck, J. -L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sureau, F.; Sutton, D.; Suur-Uski, A. -S.; Sygnet, J. -F.; Tauber, J.A.; Tavagnacco, D.; Terenzi, L.; Thomas, H.S.; Toffolatti, L.; Tomasi, M.; Torii, K.; Tristram, M.; Tucci, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L.A.; Wandelt, B.D.; Wehus, I.K.; Yoda, H. Yamamoto T.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-10-29

    Rotational transition lines of CO play a major role in molecular radio astronomy and in particular in the study of star formation and the Galactic structure. Although a wealth of data exists in the Galactic plane and some well-known molecular clouds, there is no available CO high sensitivity all-sky survey to date. Such all-sky surveys can be constructed using the \\Planck\\ HFI data because the three lowest CO rotational transition lines at 115, 230 and 345 GHz significantly contribute to the signal of the 100, 217 and 353 GHz HFI channels respectively. Two different component separation methods are used to extract the CO maps from Planck HFI data. The maps obtained are then compared to one another and to existing external CO surveys. From these quality checks the best CO maps in terms of signal to noise and/or residual foreground contamination are selected. Three sets of velocity-integrated CO emission maps are produced: Type 1 maps of the CO (1-0), (2-1), and (3-2) rotational transitions with low foreground ...

  3. STELLAR TRANSITS IN ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Béky, Bence; Kocsis, Bence

    2013-01-01

    Supermassive black holes (SMBHs) are typically surrounded by a dense stellar population in galactic nuclei. Stars crossing the line of site in active galactic nuclei (AGNs) produce a characteristic transit light curve, just like extrasolar planets do when they transit their host star. We examine the possibility of finding such AGN transits in deep optical, UV, and X-ray surveys. We calculate transit light curves using the Novikov-Thorne thin accretion disk model, including general relativistic effects. Based on the expected properties of stellar cusps, we find that around 10 6 solar mass SMBHs, transits of red giants are most common for stars on close orbits with transit durations of a few weeks and orbital periods of a few years. We find that detecting AGN transits requires repeated observations of thousands of low-mass AGNs to 1% photometric accuracy in optical, or ∼10% in UV bands or soft X-ray. It may be possible to identify stellar transits in the Pan-STARRS and LSST optical and the eROSITA X-ray surveys. Such observations could be used to constrain black hole mass, spin, inclination, and accretion rate. Transit rates and durations could give valuable information on the circumnuclear stellar clusters as well. Transit light curves could be used to image accretion disks with unprecedented resolution, allowing us to resolve the SMBH silhouette in distant AGNs.

  4. Wolf-Rayet stars and galactic structure

    International Nuclear Information System (INIS)

    Stenholm, B.

    1975-01-01

    A 15 0 wide strip along the galactic equator between longitudes 250 0 and 360 0 has been searched for Wolf-Rayet stars. Six new WR stars and four new planetary nebulae have been found. Seven stars earlier listed as WR stars have been rejected as such. The new WR stars in the 'Luminous Stars in the Southern Milky Way' are discussed. A sample of 154 WR stars has been treated statistically. For the distribution in longitude, comparisons are made with OB stars and classical cepheids. The differences in distribution are thought to be an age effect. An effort to explain the empty interval towards the anticentre is made. The distribution in latitude is compared with young clusters and long-period cepheids. The physical plane formed by these objects is tilted about one degree to the galactic plane and the tilt is upwards in the Cygnus direction. This result is also received by a least squares solution of the objects when given in rectangular coordinates. The WR star sample is regarded as fairly complete up to a distance of 5 kpc. (orig.) [de

  5. Is dark matter visible by galactic gamma rays?

    Indian Academy of Sciences (India)

    Abstract. The EGRET excess in the diffuse galactic gamma ray data above 1 GeV shows all features expected from dark matter WIMP annihilation: (a) It is present and has the same spectrum in all sky directions, not just in the galactic plane. (b) The intensity of the excess shows the 1/r2 profile expected for a flat rotation ...

  6. Is dark matter visible by galactic gamma rays?

    Indian Academy of Sciences (India)

    The EGRET excess in the diffuse galactic gamma ray data above 1 GeV shows all features expected from dark matter WIMP annihilation: (a) It is present and has the same spectrum in all sky directions, not just in the galactic plane. (b) The intensity of the excess shows the 1/2 profile expected for a flat rotation curve outside ...

  7. Very High Energy γ- rays from Galactic Sources

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. The field of Very High Energy (VHE) gamma ray astron- omy using the Atmospheric Cerenkov Technique has entered an interesting phase with detection of various galactic and extragalactic sources. Among galactic sources, only the Crab nebula has been established as a standard candle. Most observations on ...

  8. The scientific legacy of Howard Vincent Malmstadt

    International Nuclear Information System (INIS)

    Horlick, Gary

    2006-01-01

    Howard Malmstadt was a true giant of Analytical Chemistry and clearly one of the most influential analytical chemists of the last 50 years. Howard, through his own work and that of his students (first generation) and their students (second generation) and their students' students (third generation) changed the course of Analytical Chemistry. His research interests were broad and ranged from analytical solution chemistry (titrimetry and reaction rates) and electrochemistry to atomic and molecular spectroscopy, chemical instrumentation, clinical chemistry and automation. Howard was also one of the most innovative and influential educators of our time. He changed forever the analytical curriculum through his many books on Electronics for Scientists, most written in conjunction with Chris Enke and Stan Crouch. Their texts and short courses went from pioneering the application of tube-based analog electronics (servo systems and operational amplifiers) in scientific measurements to the impact that integrated circuits and digital electronics would have on laboratory measurements. He strongly believed in the importance of 'hands-on' in education. To this end, he expended considerable personal effort and time to see not only the development and commercialization of an effective laboratory infrastructure to support education in analog and digital electronics, but also oversaw the development of modular instrumentation for spectroscopy. Over the years he received many awards from the Analytical Chemistry community for his outstanding efforts and contributions to teaching and research. Many of Howard's students went on into academia. They and their students now represent the ongoing legacy for analytical chemistry that evolved from Howard's laboratory at Illinois. A remarkable diversity of research programs are underway in their laboratories. Topics range from atomic, laser, mass, and Raman spectroscopy to detection technology, analytical education, micro

  9. The Environmental Legacy of Modern Tropical Deforestation.

    Science.gov (United States)

    Rosa, Isabel M D; Smith, Matthew J; Wearn, Oliver R; Purves, Drew; Ewers, Robert M

    2016-08-22

    Tropical deforestation has caused a significant share of carbon emissions and species losses, but historical patterns have rarely been explicitly considered when estimating these impacts [1]. A deforestation event today leads to a time-delayed future release of carbon, from the eventual decay either of forest products or of slash left at the site [2]. Similarly, deforestation often does not result in the immediate loss of species, and communities may exhibit a process of "relaxation" to their new equilibrium over time [3]. We used a spatially explicit land cover change model [4] to reconstruct the annual rates and spatial patterns of tropical deforestation that occurred between 1950 and 2009 in the Amazon, in the Congo Basin, and across Southeast Asia. Using these patterns, we estimated the resulting gross vegetation carbon emissions [2, 5] and species losses over time [6]. Importantly, we accounted for the time lags inherent in both the release of carbon and the extinction of species. We show that even if deforestation had completely halted in 2010, time lags ensured there would still be a carbon emissions debt of at least 8.6 petagrams, equivalent to 5-10 years of global deforestation, and an extinction debt of more than 140 bird, mammal, and amphibian forest-specific species, which if paid, would increase the number of 20(th)-century extinctions in these groups by 120%. Given the magnitude of these debts, commitments to reduce emissions and biodiversity loss are unlikely to be realized without specific actions that directly address this damaging environmental legacy. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Astronomy Legacy Project - Pisgah Astronomical Research Institute

    Science.gov (United States)

    Barker, Thurburn; Castelaz, Michael W.; Rottler, Lee; Cline, J. Donald

    2016-01-01

    Pisgah Astronomical Research Institute (PARI) is a not-for-profit public foundation in North Carolina dedicated to providing hands-on educational and research opportunities for a broad cross-section of users in science, technology, engineering and math (STEM) disciplines. In November 2007 a Workshop on a National Plan for Preserving Astronomical Photographic Data (2009ASPC,410,33O, Osborn, W. & Robbins, L) was held at PARI. The result was the establishment of the Astronomical Photographic Data Archive (APDA) at PARI. In late 2013 PARI began ALP (Astronomy Legacy Project). ALP's purpose is to digitize an extensive set of twentieth century photographic astronomical data housed in APDA. Because of the wide range of types of plates, plate dimensions and emulsions found among the 40+ collections, plate digitization will require a versatile set of scanners and digitizing instruments. Internet crowdfunding was used to assist in the purchase of additional digitization equipment that were described at AstroPlate2014 Plate Preservation Workshop (www.astroplate.cz) held in Prague, CZ, March, 2014. Equipment purchased included an Epson Expression 11000XL scanner and two Nikon D800E cameras. These digital instruments will compliment a STScI GAMMA scanner now located in APDA. GAMMA will be adapted to use an electroluminescence light source and a digital camera with a telecentric lens to achieve high-speed high-resolution scanning. The 1μm precision XY stage of GAMMA will allow very precise positioning of the plate stage. Multiple overlapping CCD images of small sections of each plate, tiles, will be combined using a photo-mosaic process similar to one used in Harvard's DASCH project. Implementation of a software pipeline for the creation of a SQL database containing plate images and metadata will be based upon APPLAUSE as described by Tuvikene at AstroPlate2014 (www.astroplate.cz/programs/).

  11. The climate of HD 189733b from fourteen transits and eclipses measured by Spitzer

    Energy Technology Data Exchange (ETDEWEB)

    Agol, E.; /Washington U., Seattle, Astron. Dept. /Santa Barbara, KITP /UC, Santa Barbara; Cowan, Nicolas B.; /Washington U., Seattle, Astron. Dept.; Knutson, Heather A.; /UC, Berkeley, Astron. Dept.; Deming, Drake; /NASA, Goddard; Steffen, Jason H.; /Fermilab; Henry, Gregory W.; /Tennessee State U.; Charbonneau, David; /Harvard-Smithsonian Ctr. Astrophys.

    2010-07-01

    We present observations of six transits and six eclipses of the transiting planet system HD 189733 taken with the Spitzer Space Telescope IRAC camera at 8 microns, as well as a re-analysis of previously published data. We use several novel techniques in our data analysis, the most important of which is a new correction for the detector 'ramp' variation with a double-exponential function which performs better and is a better physical model for this detector variation. Our main scientific findings are: (1) an upper limit on the variability of the day-side planet flux of 2.7% (68% confidence); (2) the most precise set of transit times measured for a transiting planet, with an average accuracy of 3 seconds; (3) a lack of transit-timing variations, excluding the presence of second planets in this system above 20% of the mass of Mars in low-order mean-motion resonance at 95% confidence; (4) a confirmation of the planet's phase variation, finding the night side is 64% as bright as the day side, as well as an upper limit on the night-side variability of 17% (68% confidence); (5) a better correction for stellar variability at 8 micron causing the phase function to peak 3.5 hours before secondary eclipse, confirming that the advection and radiation timescales are comparable at the 8 micron photosphere; (6) variation in the depth of transit, which possibly implies variations in the surface brightness of the portion of the star occulted by the planet, posing a fundamental limit on non-simultaneous multi-wavelength transit absorption measurements of planet atmospheres; (7) a measurement of the infrared limb-darkening of the star, which is in good agreement with stellar atmosphere models; (8) an offset in the times of secondary eclipse of 69 seconds, which is mostly accounted for by a 31 second light travel time delay and 33 second delay due to the shift of ingress and egress by the planet hot spot; this confirms that the phase variation is due to an offset hot

  12. LUMINOSITY FUNCTIONS OF SPITZER-IDENTIFIED PROTOSTARS IN NINE NEARBY MOLECULAR CLOUDS

    International Nuclear Information System (INIS)

    Kryukova, E.; Megeath, S. T.; Allen, T. S.; Gutermuth, R. A.; Pipher, J.; Allen, L. E.; Myers, P. C.; Muzerolle, J.

    2012-01-01

    We identify protostars in Spitzer surveys of nine star-forming (SF) molecular clouds within 1 kpc: Serpens, Perseus, Ophiuchus, Chamaeleon, Lupus, Taurus, Orion, Cep OB3, and Mon R2, which combined host over 700 protostar candidates. These clouds encompass a variety of SF environments, including both low-mass and high-mass SF regions, as well as dense clusters and regions of sparsely distributed star formation. Our diverse cloud sample allows us to compare protostar luminosity functions in these varied environments. We combine near- and mid-infrared photometry from the Two Micron All Sky Survey and Spitzer to create 1-24 μm spectral energy distributions (SEDs). Using protostars from the c2d survey with well-determined bolometric luminosities, we derive a relationship between bolometric luminosity, mid-IR luminosity (integrated from 1-24 μm), and SED slope. Estimations of the bolometric luminosities for protostar candidates are combined to create luminosity functions for each cloud. Contamination due to edge-on disks, reddened Class II sources, and galaxies is estimated and removed from the luminosity functions. We find that luminosity functions for high-mass SF clouds (Orion, Mon R2, and Cep OB3) peak near 1 L ☉ and show a tail extending toward luminosities above 100 L ☉ . The luminosity functions of the low-mass SF clouds (Serpens, Perseus, Ophiuchus, Taurus, Lupus, and Chamaeleon) do not exhibit a common peak, however the combined luminosity function of these regions peaks below 1 L ☉ . Finally, we examine the luminosity functions as a function of the local surface density of young stellar objects. In the Orion molecular clouds, we find a significant difference between the luminosity functions of protostars in regions of high and low stellar density, the former of which is biased toward more luminous sources. This may be the result of primordial mass segregation, although this interpretation is not unique. We compare our luminosity functions to those

  13. LUMINOSITY FUNCTIONS OF SPITZER-IDENTIFIED PROTOSTARS IN NINE NEARBY MOLECULAR CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Kryukova, E.; Megeath, S. T.; Allen, T. S. [Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States); Gutermuth, R. A. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Pipher, J. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Allen, L. E. [National Optical Astronomy Observatories, Tucson, AZ (United States); Myers, P. C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Muzerolle, J. [Space Telescope Science Institute, Baltimore, MD (United States)

    2012-08-15

    We identify protostars in Spitzer surveys of nine star-forming (SF) molecular clouds within 1 kpc: Serpens, Perseus, Ophiuchus, Chamaeleon, Lupus, Taurus, Orion, Cep OB3, and Mon R2, which combined host over 700 protostar candidates. These clouds encompass a variety of SF environments, including both low-mass and high-mass SF regions, as well as dense clusters and regions of sparsely distributed star formation. Our diverse cloud sample allows us to compare protostar luminosity functions in these varied environments. We combine near- and mid-infrared photometry from the Two Micron All Sky Survey and Spitzer to create 1-24 {mu}m spectral energy distributions (SEDs). Using protostars from the c2d survey with well-determined bolometric luminosities, we derive a relationship between bolometric luminosity, mid-IR luminosity (integrated from 1-24 {mu}m), and SED slope. Estimations of the bolometric luminosities for protostar candidates are combined to create luminosity functions for each cloud. Contamination due to edge-on disks, reddened Class II sources, and galaxies is estimated and removed from the luminosity functions. We find that luminosity functions for high-mass SF clouds (Orion, Mon R2, and Cep OB3) peak near 1 L{sub Sun} and show a tail extending toward luminosities above 100 L{sub Sun }. The luminosity functions of the low-mass SF clouds (Serpens, Perseus, Ophiuchus, Taurus, Lupus, and Chamaeleon) do not exhibit a common peak, however the combined luminosity function of these regions peaks below 1 L{sub Sun }. Finally, we examine the luminosity functions as a function of the local surface density of young stellar objects. In the Orion molecular clouds, we find a significant difference between the luminosity functions of protostars in regions of high and low stellar density, the former of which is biased toward more luminous sources. This may be the result of primordial mass segregation, although this interpretation is not unique. We compare our luminosity

  14. Revisiting the Phase Curves of WASP-43b: Confronting Re-analyzed Spitzer Data with Cloudy Atmospheres

    DEFF Research Database (Denmark)

    Mendonça, João M.; Malik, Matej; Demory, Brice-Olivier

    2018-01-01

    and have a finite cloud-top pressure. The multi-wavelength phase curves are naturally consistent with our cloudy atmospheres, except for the 4.5 μm phase curve, which requires the presence of enhanced carbon dioxide in the atmosphere of WASP-43b. Multi-phase emission spectra at higher spectral resolution......Recently acquired Hubble and Spitzer phase curves of the short-period hot Jupiter WASP-43b make it an ideal target for confronting theory with data. On the observational front, we re-analyze the 3.6 and 4.5 μm Spitzer phase curves and demonstrate that our improved analysis better removes residual...

  15. CRYSTALLINE SILICATES IN EVOLVED STARS. I. SPITZER/INFRARED SPECTROGRAPH SPECTROSCOPY OF IRAS 16456-3542, 18354-0638, AND 23239+5754

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, B. W.; Zhang, Ke [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Li, Aigen [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States); Lisse, C. M., E-mail: bjiang@bnu.edu.cn, E-mail: kzhang@caltech.edu, E-mail: lia@missouri.edu, E-mail: carey.lisse@jhuapl.edu [Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States)

    2013-03-01

    We report the Spitzer Infrared Spectrograph (IRS) observations of three evolved stars: IRAS 16456-3542, 18354-0638, and 23239+5754. The 9.9-37.2 {mu}m Spitzer/IRS high-resolution spectra of these three sources exhibit rich sets of enstatite-dominated crystalline silicate emission features. IRAS 16456-3542 is extremely rich in crystalline silicates, with >90% of its silicate mass in crystalline form, the highest to date ever reported for crystalline silicate sources.

  16. Empirical sigma - d relations and main galactic radio loops

    Directory of Open Access Journals (Sweden)

    Urošević Dejan V.

    2002-01-01

    Full Text Available This paper represents a review of the empirical Galactic and extragalactic sigma - D relations (relations between the surface brightness sigma and the diameter D for supernova remnants (SNRs, with checking the connection of the main Galactic radio loops (Loop I, II, III and IV with these relations. We present results which suggest, in another way, that the radio loops may have an SNR origin. The updated relations have been measured to have slopes beta = 2 in log-log space. The best sigma - D relations for M31 and M33 galaxies were derived and these relations are shown to be flatter (beta < 2 than those for Galactic SNRs alone. This result confirms that selection effects play an important role in data-sets made up of Galactic SNRs. A sigma - D relation with 157 reliable calibrators (both Galactic and extragalactic is derived. This relation also has a slope beta = 2.07 ± 13.

  17. Constraints on Galactic populations from the unidentified EGRET sources

    International Nuclear Information System (INIS)

    Siegal-Gaskins, Jennifer M.; Pavlidou, Vasiliki; Brown, Carolyn; Olinto, Angela V.; Fields, Brian D.

    2007-01-01

    A significant fraction of the sources in the third EGRET catalog have not yet been identified with a low-energy counterpart. We evaluate the plausibility of a Galactic population accounting for some or all of the unidentified EGRET sources by making the simple assumption that galaxies similar to the Milky Way host comparable populations of gamma-ray emitters. Rather than focusing on the properties of a specific candidate emitter, we constrain the abundance and spatial distribution of proposed Galactic populations. We find that it is highly improbable that the unidentified EGRET sources contain more than a handful of members of a Galactic halo population, but that current observations are consistent with all of these sources being Galactic objects if they reside entirely in the disk and bulge. We discuss the additional constraints and new insights into the nature of Galactic gamma-ray emitting populations that GLAST is expected to provide

  18. Positron annihilation radiation from the Galactic center region

    Science.gov (United States)

    Ramaty, R.; Lingenfelter, R. E.

    1991-01-01

    Observations show that there are two components of positron annihilation radiation from the region of the Galactic center: a variable component resulting from one or just a few compact sources at or near the Galactic center and a steady, diffuse component resulting from positron annihilation in the Galactic disk. The diffuse component is modeled using the observed longitude distributions of 70-150 MeV gamma rays, CO, and hot plasma revealed by Fe line emission. Recent results on positron annihilation in the interstellar medium are reviewed and the implications of the annihilation processes on the fraction of positrons annihilating via positronium and on the shape of the 511 keV annihilation line are discussed. The sources of diffuse Galactic positrons are also reviewed and the nature of the compact source of annihilation radiation near the Galactic center is discussed.

  19. SPITZER IRS SPECTRA OF LUMINOUS 8 μm SOURCES IN THE LARGE MAGELLANIC CLOUD: TESTING COLOR-BASED CLASSIFICATIONS

    International Nuclear Information System (INIS)

    Buchanan, Catherine L.; Kastner, Joel H.; Hrivnak, Bruce J.; Sahai, Raghvendra

    2009-01-01

    We present archival Spitzer Infrared Spectrograph (IRS) spectra of 19 luminous 8 μm selected sources in the Large Magellanic Cloud (LMC). The object classes derived from these spectra and from an additional 24 spectra in the literature are compared with classifications based on Two Micron All Sky Survey (2MASS)/MSX (J, H, K, and 8 μm) colors in order to test the 'JHK8' (Kastner et al.) classification scheme. The IRS spectra confirm the classifications of 22 of the 31 sources that can be classified under the JHK8 system. The spectroscopic classification of 12 objects that were unclassifiable in the JHK8 scheme allow us to characterize regions of the color-color diagrams that previously lacked spectroscopic verification, enabling refinements to the JHK8 classification system. The results of these new classifications are consistent with previous results concerning the identification of the most infrared-luminous objects in the LMC. In particular, while the IRS spectra reveal several new examples of asymptotic giant branch (AGB) stars with O-rich envelopes, such objects are still far outnumbered by carbon stars (C-rich AGB stars). We show that Spitzer IRAC/MIPS color-color diagrams provide improved discrimination between red supergiants and oxygen-rich and carbon-rich AGB stars relative to those based on 2MASS/MSX colors. These diagrams will enable the most luminous IR sources in Local Group galaxies to be classified with high confidence based on their Spitzer colors. Such characterizations of stellar populations will continue to be possible during Spitzer's warm mission through the use of IRAC [3.6]-[4.5] and 2MASS colors.

  20. The impact of Spitzer infrared data on stellar mass estimates - and a revised galaxy stellar mass function at 0 < z < 5

    Science.gov (United States)

    Elsner, F.; Feulner, G.; Hopp, U.

    2008-01-01

    Aims:We estimate stellar masses of galaxies in the high redshift universe with the intention of determining the influence of newly available Spitzer/IRAC infrared data on the analysis. Based on the results, we probe the mass assembly history of the universe. Methods: We use the GOODS-MUSIC catalog, which provides multiband photometry from the U-filter to the 8 μm Spitzer band for almost 15 000 galaxies with either spectroscopic (for ≈7% of the sample) or photometric redshifts, and apply a standard model fitting technique to estimate stellar masses. We than repeat our calculations with fixed photometric redshifts excluding Spitzer photometry and directly compare the outcomes to look for systematic deviations. Finally we use our results to compute stellar mass functions and mass densities up to redshift z = 5. Results: We find that stellar masses tend to be overestimated on average if further constraining Spitzer data are not included into the analysis. Whilst this trend is small up to intermediate redshifts z ⪉ 2.5 and falls within the typical error in mass, the deviation increases strongly for higher redshifts and reaches a maximum of a factor of three at redshift z ≈ 3.5. Thus, up to intermediate redshifts, results for stellar mass density are in good agreement with values taken from literature calculated without additional Spitzer photometry. At higher redshifts, however, we find a systematic trend towards lower mass densities if Spitzer/IRAC data are included.

  1. Surveys Of The Galactic Plane For Pulsars

    Science.gov (United States)

    Bates, S. D.

    2011-03-01

    Since their discovery in 1968, the known population of radio pulsars has grown to ~2000, and comprises several different groups which display markedly different behaviour from one another. Despite the large number of known sources, there are several scientific justifications for new wide-area searches for pulsars. These are outlined in this work, but include population studies, the evolutionary history of pulsars, and the possible detection of gravitational waves through high-precision timing.Previous pulsar surveys have been limited by (a) the hardware used to record the survey data; and, (b) the computational power that has been available to process this data. This has resulted in an observational bias which made the discovery of distant, highly dispersed pulsars, very difficult. Particularly affected by this are the most rapidly-rotating pulsars --- the millisecond pulsars --- which are known to rotate with spin periods as short as 1.4 ms. Since these are also some of the most interesting sources, with the greatest potential for high-precision timing, it is important to perform searches both deep into the Galactic plane and covering the whole sky, with sufficient time resolution to discover more millisecond pulsars. This thesis describes two such pulsar surveys, in which several discoveries have been made.The first is a survey of the Galactic plane at an observing frequency of 6.5 GHz, motivated by the need to discover pulsars at the Galactic centre. This survey resulted in the discovery of three pulsars, all of which are at distances > 9.5 kpc.The second is the ongoing High Time Resolution Universe pulsar survey using the 64-metre telescope at Parkes. This survey will make observations of the whole of the Southern sky using extremely high time resolution and narrow frequency channels. Preliminary results from the survey are presented here, including the discovery of 5 millisecond pulsars at relatively large distances, including one for which regular eclipses

  2. Climate legacies drive global soil carbon stocks in terrestrial ecosystems.

    Science.gov (United States)

    Delgado-Baquerizo, Manuel; Eldridge, David J; Maestre, Fernando T; Karunaratne, Senani B; Trivedi, Pankaj; Reich, Peter B; Singh, Brajesh K

    2017-04-01

    Climatic conditions shift gradually over millennia, altering the rates at which carbon (C) is fixed from the atmosphere and stored in the soil. However, legacy impacts of past climates on current soil C stocks are poorly understood. We used data from more than 5000 terrestrial sites from three global and regional data sets to identify the relative importance of current and past (Last Glacial Maximum and mid-Holocene) climatic conditions in regulating soil C stocks in natural and agricultural areas. Paleoclimate always explained a greater amount of the variance in soil C stocks than current climate at regional and global scales. Our results indicate that climatic legacies help determine global soil C stocks in terrestrial ecosystems where agriculture is highly dependent on current climatic conditions. Our findings emphasize the importance of considering how climate legacies influence soil C content, allowing us to improve quantitative predictions of global C stocks under different climatic scenarios.

  3. Developing a TTCN-3 Test Harness for Legacy Software

    DEFF Research Database (Denmark)

    Okika, Joseph C.; Ravn, Anders Peter; Siddalingaiah, Lokesh

    2006-01-01

    challenge in developing the test harness is to interface a generic test driver to the legacy software and provide a suitable interface for test engineers. The main contribution of this paper is a demonstration of a suitable design for such a test harness. It includes: a TTCN-3 test driver in C++, the legacy...... control software in C, a Graphical User Interface (GUI) and the connectors in Java. Our experience shows that it is feasible to use TTCN-3 in developing a test harness for a legacy software for an embedded system, even when it involves different heterogeneous components.......We describe a prototype test harness for an embedded system which is the control software for a modern marine diesel engine. The operations of such control software requires complete certification. We adopt Testing and Test Control Notation (TTCN-3) to define test cases for this purpose. The main...

  4. Developing a TTCN-3 Test Harness for Legacy Software

    DEFF Research Database (Denmark)

    Okika, Joseph C.; Ravn, Anders Peter; Siddalingaiah, Lokesh

    2006-01-01

    We describe a prototype test harness for an embedded system which is the control software for a modern marine diesel engine. The operations of such control software requires complete certification. We adopt Testing and Test Control Notation (TTCN-3) to define test cases for this purpose. The main...... challenge in developing the test harness is to interface a generic test driver to the legacy software and provide a suitable interface for test engineers. The main contribution of this paper is a demonstration of a suitable design for such a test harness. It includes: a TTCN-3 test driver in C++, the legacy...... control software in C, a Graphical User Interface (GUI) and the connectors in Java. Our experience shows that it is feasible to use TTCN-3 in developing a test harness for a legacy software for an embedded system, even when it involves different heterogeneous components....

  5. U.S. Spacesuit Legacy: Maintaining it for the Future

    Science.gov (United States)

    Chullen, Cinda; McMann, Joe; Thomas, Ken; Kosmo, Joe; Lewis, Cathleen; Wright, Rebecca; Bitterly, Rose; Olivia, Vladenka Rose

    2013-01-01

    The history of U.S. spacesuit development and its use are rich with information on lessons learned, and constitutes a valuable legacy to those designing spacesuits for the future, as well as to educators, students, and the general public. The genesis of lessons learned is best understood by studying the evolution of past spacesuit programs - how the challenges and pressures of the times influenced the direction of the various spacesuit programs. This paper shows how the legacy of various spacesuit-related programs evolved in response to these forces. Important aspects of how this U.S. spacesuit legacy is being preserved today is described, including the archiving of spacesuit hardware, important documents, videos, oral history, and the rapidly expanding U.S. Spacesuit Knowledge Capture program.

  6. Legacy to Industry 4.0: A Profibus Sniffer

    Science.gov (United States)

    Tsegaye Mamo, Fesseha; Sikora, Axel; Rathfelder, Christoph

    2017-07-01

    Legacy industrial communication protocols are proved robust and functional. During the last decades, the industry has invented completely new or advanced versions of the legacy communication solutions. However, even with the high adoption rate of these new solutions, still the majority industry applications run on legacy, mostly fieldbus related technologies. Profibus is one of those technologies that still keep on growing in the market, albeit a slow in market growth in recent years. A retrofit technology that would enable these technologies to connect to the Internet of Things, utilize the ever growing potential of data analysis, predictive maintenance or cloud-based application, while at the same time not changing a running system is fundamental.

  7. Properties of the Irregular Satellite System around Uranus Inferred from K2 , Herschel , and Spitzer Observations

    Energy Technology Data Exchange (ETDEWEB)

    Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; Sárneczky, K.; Szabó, R.; Marton, G.; Szakáts, R.; Kiss, L. L. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklós út 15-17, H-1121 Budapest (Hungary); Mommert, M. [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States); Müller, T., E-mail: farkas.aniko@csfk.mta.hu [Max-Plank-Institut für extraterrestrsiche Pyhsik, Garching (Germany)

    2017-09-01

    In this paper, we present visible-range light curves of the irregular Uranian satellites Sycorax, Caliban, Prospero, Ferdinand, and Setebos taken with the Kepler Space Telescope over the course of the K2 mission. Thermal emission measurements obtained with the Herschel /PACS and Spitzer /MIPS instruments of Sycorax and Caliban were also analyzed and used to determine size, albedo, and surface characteristics of these bodies. We compare these properties with the rotational and surface characteristics of irregular satellites in other giant planet systems and also with those of main belt and Trojan asteroids and trans-Neptunian objects. Our results indicate that the Uranian irregular satellite system likely went through a more intense collisional evolution than the irregular satellites of Jupiter and Saturn. Surface characteristics of Uranian irregular satellites seem to resemble the Centaurs and trans-Neptunian objects more than irregular satellites around other giant planets, suggesting the existence of a compositional discontinuity in the young solar system inside the orbit of Uranus.

  8. SPITZER OBSERVATIONS OF LONG-TERM INFRARED VARIABILITY AMONG YOUNG STELLAR OBJECTS IN CHAMAELEON I

    Energy Technology Data Exchange (ETDEWEB)

    Flaherty, Kevin M.; Herbst, William [Van Vleck Observatory, Astronomy Department, Wesleyan University, 96 Foss Hill Drive, Middletown, CT 06459 (United States); DeMarchi, Lindsay [Department of Physics and Astronomy, Colgate University, 13 Oak Drive, Hamilton, NY 13346 (United States); Muzerolle, James [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Balog, Zoltan [Max-Planck-Institut fur Astronomie, Konigstuhl 17, D-69117 Heidelberg (Germany); Megeath, S. Thomas [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Furlan, Elise [Infrared Processing and Analysis Center, California Institute of Technology, 770 S. Wilson Avenue, Pasadena, CA 91125 (United States); Gutermuth, Robert [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2016-12-10

    Infrared variability is common among young stellar objects, with surveys finding daily to weekly fluctuations of a few tenths of a magnitude. Space-based observations can produce highly sampled infrared light curves, but are often limited to total baselines of about 1 month due to the orientation of the spacecraft. Here we present observations of the Chameleon I cluster, whose low declination makes it observable by the Spitzer Space Telescope over a 200-day period. We observe 30 young stellar objects with a daily cadence to better sample variability on timescales of months. We find that such variability is common, occurring in ∼80% of the detected cluster members. The change in [3.6]–[4.5] color over 200 days for many of the sources falls between that expected for extinction and fluctuations in disk emission. With our high cadence and long baseline we can derive power spectral density curves covering two orders of magnitude in frequency and find significant power at low frequencies, up to the boundaries of our 200-day survey. Such long timescales are difficult to explain with variations driven by the interaction between the disk and stellar magnetic field, which has a dynamical timescale of days to weeks. The most likely explanation is either structural or temperature fluctuations spread throughout the inner ∼0.5 au of the disk, suggesting that the intrinsic dust structure is highly dynamic.

  9. Stellar mass estimation based on IRAC photometry for Spitzer SWIRE-field galaxies

    International Nuclear Information System (INIS)

    Zhu Yinan; Wu Hong; Li Haining; Cao Chen

    2010-01-01

    We analyze the feasibility of estimating the stellar mass of galaxies by mid-infrared luminosities based on a large sample of galaxies cross-identified from Spitzer SWIRE fields and the SDSS spectrographic survey. We derived the formulae to calculate the stellar mass by using IRAC 3.6 μm and 4.5 μm luminosities. The mass-to-luminosity ratios of IRAC 3.6 μm and 4.5 μm luminosities are more sensitive to the star formation history of galaxies than to other factors, such as the intrinsic extinction, metallicity and star formation rate. To remove the effect of star formation history, we used g - r color to recalibrate the formulae and obtain a better result. Researchers must be more careful when estimating the stellar mass of low metallicity galaxies using our formulae. Due to the emission from dust heated by the hottest young stars, luminous infrared galaxies present higher IRAC 4.5 μm luminosities compared to IRAC 3.6 μm luminosities. For most of type-II AGNs, the nuclear activity cannot enhance 3.6 μm and 4.5 μm luminosities compared with normal galaxies. Star formation in our AGN-hosting galaxies is also very weak, almost all of which are early-type galaxies.

  10. VizieR Online Data Catalog: Spitzer h and {chi} Persei candidate members (Cloutier+, 2014)

    Science.gov (United States)

    Cloutier, R.; Currie, T.; Rieke, G. H.; Kenyon, S. J.; Balog, Z.; Jayawardhana, R.

    2017-08-01

    The IRAC (Fazio et al. 2004ApJS..154...39F) observed h and {chi} Persei on October 30, 2008 (AOR IDs 2182740, 21828608, 21828096, 21828864, 21828352, and 2182912). Solar activity was normal to below average. Zodical emission ranged between ~0.02 and 2 MJy/sr from 3.6 um to 8 um. Image processing and photometry were performed separately for the short-exposure and long-exposure frames. The MIPS (Rieke et al. 2004ApJS..154...25R) imaged h and {chi} Persei on 2008 March 15-16, 2008 October 25-26, and 2009 March 26 and 29 as a part of General Observation Programs 40690 and 50664 (PI: Scott Kenyon). To identify and characterize disks surrounding h and {chi} Persei stars, we combine Spitzer data with optical/near-IR data for likely cluster members, updating the list from Currie et al. (2010, J/ApJS/186/191) with a more accurate one of 13956 stars (Table 1). (3 data files).

  11. Dark matter superfluidity and galactic dynamics

    Directory of Open Access Journals (Sweden)

    Lasha Berezhiani

    2016-02-01

    Full Text Available We propose a unified framework that reconciles the stunning success of MOND on galactic scales with the triumph of the ΛCDM model on cosmological scales. This is achieved through the physics of superfluidity. Dark matter consists of self-interacting axion-like particles that thermalize and condense to form a superfluid in galaxies, with ∼mK critical temperature. The superfluid phonons mediate a MOND acceleration on baryonic matter. Our framework naturally distinguishes between galaxies (where MOND is successful and galaxy clusters (where MOND is not: dark matter has a higher temperature in clusters, and hence is in a mixture of superfluid and normal phase. The rich and well-studied physics of superfluidity leads to a number of striking observational signatures.

  12. Gamma-Rays from Galactic Compact Sources

    Science.gov (United States)

    Kaaret, Philip

    2007-04-01

    Recent discoveries have revealed many sources of TeV photons in our Mikly Way galaxy powered by compact objects, either neutron stars or black holes. These objects must be powerful particle accelerators, some with peak energies of at least 100 TeV, and may be neutrino, as well as photon, sources. Future TeV observations will enable us to address key questions concerning particle acceleration by compact objects including the fraction of energy which accreting black holes channel into relativstic jet production, whether the compact object jets are leptonic or hadronic, and the mechanism by which pulsar winds accelerate relativistic particles. We report on work done related to compact Galactic objects in preparation of a White Paper on the status and future of ground-based gamma-ray astronomy requested by the Division of Astrophysics of the American Physical Society.

  13. SYNCHROTRON EMISSION FROM THE GALACTIC HI LAYER

    Directory of Open Access Journals (Sweden)

    Yonggi Kim

    2007-03-01

    Full Text Available The relationship between the Galactic magnetic field strength and the gas density has been revisited. A synchrotron continuum emission data at 408 MHz and HI column density provide a good data for such study. But it is difficult to separate the synchrotron emission from the observed 408MHz radio emission, because the 408MHz radio emission has the component from the HI layer, as well as many components from other origins. We have tried to substract the component which is probably not related with HI layer, and present the results. We show that the method presented here is a more refined method than that of Brown & Chang (1983, hearafter BC83 to find the above mentioned relationship, and discuss the existence of such relationship in our Galaxy.

  14. The propagation of galactic cosmic rays

    International Nuclear Information System (INIS)

    Hall, A.N.

    1981-01-01

    Large scale (approximately 15 pc) turbulence in the interstellar medium (ISM) causes the firehose and mirror instabilities to occur. These produce small scale (approximately 10 -7 pc) magnetic irregularities, which scatter cosmic rays. We use pulsar scintillation data, and a model of the origin of these scintillations, to construct a slab model of the turbulent ISM. Then we find the amplitudes and wavelengths of the magnetic irregularities that arise, and we calculate the coefficients for the diffusion of cosmic rays along the interstellar magnetic fields. We incorporate this diffusion into our model of the turbulent ISM, and show that it can account naturally for both the lifetime of low energy cosmic rays, and the variation of their mean pathlength with energy. Our model has no galactic halo, and contains no scattering by Alfven waves. (author)

  15. Galactic TeV observations with HAWC

    Science.gov (United States)

    Hui, Chiumun Michelle

    2014-08-01

    The High Altitude Water Cherenkov (HAWC) Observatory is a gamma-ray and cosmic-ray detector currently under construction at the Sierra Negra volcano in the state of Puebla, Mexico. The full array will consist of 300 water Cherenkov detectors, which contain 1200 photomultiplier tubes and cover an area of 22,000m^2. It has an instantaneous field of view of 2sr, a duty cycle >90%, and is sensitive to energies between 100 GeV and 100 TeV. Data taking began in Summer 2013 with a partial array. I will present the results of HAWC observations of the Galactic plane, which include the complex Cygnus region, and other extended TeV objects with unidentified source associations.

  16. Optical Variability of Active Galactic Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kozłowski, Szymon, E-mail: simkoz@astrouw.edu.pl [Astronomical Observatory, University of Warsaw, Warsaw (Poland)

    2017-09-21

    Variability studies of active galactic nuclei (AGNs) typically use either power spectral density (PSD) and structure function (SF) analyses or direct modeling of light curves with the damped random walk (DRW) and the continuous autoregressive moving average (CARMA) models. A fair fraction of research publications on the subject are flawed, and simply report incorrect results, because they lack a deep understanding of where these methods originate from and what their limitations are. For example, SF analyses typically lack or use a wrong noise subtraction procedure, leading to flat SFs. DRW, on the other hand, can only be used if the experiment length is sufficient, at least ten times the signal decorrelation time scale τ, and if the data show the power-law SF slope of γ ≡ 0.5.

  17. Galactic civilizations: Population dynamics and interstellar diffusion

    Science.gov (United States)

    Newman, W. I.; Sagan, C.

    1978-01-01

    The interstellar diffusion of galactic civilizations is reexamined by potential theory; both numerical and analytical solutions are derived for the nonlinear partial differential equations which specify a range of relevant models, drawn from blast wave physics, soil science, and, especially, population biology. An essential feature of these models is that, for all civilizations, population growth must be limited by the carrying capacity of the environment. Dispersal is fundamentally a diffusion process; a density-dependent diffusivity describes interstellar emigration. Two models are considered: the first describing zero population growth (ZPG), and the second which also includes local growth and saturation of a planetary population, and for which an asymptotic traveling wave solution is found.

  18. Primary nucleosynthesis in the galactic disk

    Energy Technology Data Exchange (ETDEWEB)

    Twarog, B.A.; Wheeler, J.C.

    1982-10-15

    New data on the history of production of C, O, Mg, and Fe are used to reexamine the production of heavy elements in the galactic disk. A standard infall model is used to show that a constant rate of production of heavy elements is consistent with the data and to derive net absolute amounts for several elements. Various models for nucleosynthesis by massive stars are considered. Current models are inconsistent with the simplest picture in which all stars above some limit approx.12 M/sub sun/ explode. Adopting a finite upper or lower mass cutoff to the massive stars which contribute to nucleosynthesis provides a better agreement. Any conclusions that massive stars in a particular mass range explode seem premature, especially when consideration is given to potentially significant contributions to C, O, and Fe production from Type I supernovae.

  19. SHARC II Observations of the Galactic Center

    Science.gov (United States)

    Staguhn, J. G.; Benford, D. J.; Dowell, C. D.

    2003-05-01

    We present the first images of the Galactic Center region obtained with the new Caltech Submillimeter Observatory facility camera SHARC II. Most of the observations show the 350μ m dust continuum emission from this region. The observing mode we used is similar to fast scanning. This mode does not require on- and off-source observations, since the emission from the sky and detector noise can be derived from the on source observations alone. This is possible because the fast scanning on the sky provides spatial correlations between bolometer pixels due to atmospheric emission and temporal correlations between pixels due to celestial emission. This difference of correlations permits the separation of the atmosphere from the celestial source. The observations therefore do not suffer from possible contamination from emission in an off position used for sky subtraction.

  20. HE neutrino sensitivity to galactic sources

    Energy Technology Data Exchange (ETDEWEB)

    Sestayo, Yolanda; Gross, Andreas; Resconi, Elisa; Schulz, Olaf [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    2008-07-01

    Predictions on a possible emission of high energy neutrinos from galactic sources can be extracted from the measurements of VHE gamma-rays under the assumption that proton-proton is the dominant interaction channel in such astrophysical environments. We report in this talk the conditions required to produce the observed gamma-ray flux through pp interactions as well as an estimation of the expected neutrino spectrum for sources transparent and non transparent to gamma-rays. The IceCube sensitivity to such predictions for the current configuration of IceCube (22 strings and AMANDA) and for the complete IceCube with its 80 strings is presented as well as the time required for IceCube to observe the predicted neutrino flux from each of the selected sources.

  1. A galactic microquasar mimicking winged radio galaxies.

    Science.gov (United States)

    Martí, Josep; Luque-Escamilla, Pedro L; Bosch-Ramon, Valentí; Paredes, Josep M

    2017-11-24

    A subclass of extragalactic radio sources known as winged radio galaxies has puzzled astronomers for many years. The wing features are detected at radio wavelengths as low-surface-brightness radio lobes that are clearly misaligned with respect to the main lobe axis. Different models compete to account for these peculiar structures. Here, we report observational evidence that the parsec-scale radio jets in the Galactic microquasar GRS 1758-258 give rise to a Z-shaped radio emission strongly reminiscent of the X and Z-shaped morphologies found in winged radio galaxies. This is the first time that such extended emission features are observed in a microquasar, providing a new analogy for its extragalactic relatives. From our observations, we can clearly favour the hydrodynamic backflow interpretation against other possible wing formation scenarios. Assuming that physical processes are similar, we can extrapolate this conclusion and suggest that this mechanism could also be at work in many extragalactic cases.

  2. Particle Acceleration in Active Galactic Nuclei

    Science.gov (United States)

    Miller, James A.

    1997-01-01

    The high efficiency of energy generation inferred from radio observations of quasars and X-ray observations of Seyfert active galactic nuclei (AGNs) is apparently achieved only by the gravitational conversion of the rest mass energy of accreting matter onto supermassive black holes. Evidence for the acceleration of particles to high energies by a central engine is also inferred from observations of apparent superluminal motion in flat spectrum, core-dominated radio sources. This phenomenon is widely attributed to the ejection of relativistic bulk plasma from the nuclei of active galaxies, and accounts for the existence of large scale radio jets and lobes at large distances from the central regions of radio galaxies. Reports of radio jets and superluminal motion from galactic black hole candidate X-ray sources indicate that similar processes are operating in these sources. Observations of luminous, rapidly variable high-energy radiation from active galactic nuclei (AGNs) with the Compton Gamma Ray Observatory show directly that particles are accelerated to high energies in a compact environment. The mechanisms which transform the gravitational potential energy of the infalling matter into nonthermal particle energy in galactic black hole candidates and AGNs are not conclusively identified, although several have been proposed. These include direct acceleration by static electric fields (resulting from, for example, magnetic reconnection), shock acceleration, and energy extraction from the rotational energy of Kerr black holes. The dominant acceleration mechanism(s) operating in the black hole environment can only be determined, of course, by a comparison of model predictions with observations. The purpose of the work proposed for this grant was to investigate stochastic particle acceleration through resonant interactions with plasma waves that populate the magnetosphere surrounding an accreting black hole. Stochastic acceleration has been successfully applied to the

  3. Monitoring and Mapping the Galactic Bulge

    Science.gov (United States)

    Markwardt, Craig

    Both neutron star and black hole binary transients are providing some of the most exciting RXTE science, and fortunately many are concentrated in the galactic bulge region. We propose to continue our twice weekly PCA scans of the region, which cover about 500 sq deg. The observations will be sensitive to new sources at the ~1 mCrab level (a factor of 10-60 more sensitive than the ASM in the region). We have had success finding new sources and new types of variability, including three millisecond pulsars, and new increased solid angle will improve the chances of finding more in the final RXTE years. We will continue efforts to search for variability in new and known sources. Companion follow-up proposals would be triggered by the results.

  4. New Media, Legacy Media and Misperceptions Regarding Sourcing

    Directory of Open Access Journals (Sweden)

    Stan Diel

    2017-07-01

    Full Text Available Resource dependence theory and related theories of management suggest online-only news media may displace legacy news media, but until that happens the two systems are likely to be dependent on the same resource: news. This quantitative content analysis finds that the systems exist as parallel but distinctly separate entities. Websites associated with legacy news media such as newspapers publish mostly hard news or news analysis in the form of original work. New, online-only news media publish mostly unoriginal features, but the origins of much of the content published by onlineonly media are unclear.

  5. Traceability of Software Safety Requirements in Legacy Safety Critical Systems

    Science.gov (United States)

    Hill, Janice L.

    2007-01-01

    How can traceability of software safety requirements be created for legacy safety critical systems? Requirements in safety standards are imposed most times during contract negotiations. On the other hand, there are instances where safety standards are levied on legacy safety critical systems, some of which may be considered for reuse for new applications. Safety standards often specify that software development documentation include process-oriented and technical safety requirements, and also require that system and software safety analyses are performed supporting technical safety requirements implementation. So what can be done if the requisite documents for establishing and maintaining safety requirements traceability are not available?

  6. Galactic distribution and evolution of pulsars

    International Nuclear Information System (INIS)

    Taylor, J.H.; Manchester, R.N.

    1977-01-01

    The distribution of pulsars with respect to period, z-distance, luminosity, and galactocentric radius has been investigated using data from three extensive pulsar surveys. It is shown that selection effects only slightly modify the observed period and z-distributions but strongly affect the observed luminosity function and galactic distribution. These latter two distributions are computed from the Jodrell Bank and Arecibo data, using an iterative procedure. The largest uncertainties in our results are the result of uncertainty in the adopted distance scale. Therefore, where relevant, separate calculations have been made for two values of the average interstellar electron density, , 0.02 cm -3 and 0.03 cm -3 .The derived luminosity function is closely represented by a power law with index (for logarithmic luminosity intervals) close to -1. For =0.03 cm -3 , the density of potentially observable pulsars is about 90 kpc -2 in the local region and increases with decreasing galactocentric radius. These distributions imply that the total number of pulsars in the Galaxy is about 10 5 . If only a fraction of all pulsars are observable because of beaming effects, then the total number in the Galaxy is correspondingly greater.Recent observations of pulsar proper motions show that pulsars are generally high-velocity objects. The observed z-distribution of pulsars implies that the mean age of observable pulsars does not exceed 2 x 10 6 years. With this mean age the pulsar birthrate required to maintain the observed galactic distribution is 10 -4 yr -1 kpc -2 in the local region and one pulsar birth every 6 years in the Galaxy as a whole. For =0.02 cm -3 , the corresponding rate is one birth every 40 years. These rates exceed most estimates of supernova occurrence rates and may require that all stars with mass greater than approx.2.5 Msun form pulsars at the end of their evolutionary life

  7. galpy: A python LIBRARY FOR GALACTIC DYNAMICS

    International Nuclear Information System (INIS)

    Bovy, Jo

    2015-01-01

    I describe the design, implementation, and usage of galpy, a python package for galactic-dynamics calculations. At its core, galpy consists of a general framework for representing galactic potentials both in python and in C (for accelerated computations); galpy functions, objects, and methods can generally take arbitrary combinations of these as arguments. Numerical orbit integration is supported with a variety of Runge-Kutta-type and symplectic integrators. For planar orbits, integration of the phase-space volume is also possible. galpy supports the calculation of action-angle coordinates and orbital frequencies for a given phase-space point for general spherical potentials, using state-of-the-art numerical approximations for axisymmetric potentials, and making use of a recent general approximation for any static potential. A number of different distribution functions (DFs) are also included in the current release; currently, these consist of two-dimensional axisymmetric and non-axisymmetric disk DFs, a three-dimensional disk DF, and a DF framework for tidal streams. I provide several examples to illustrate the use of the code. I present a simple model for the Milky Way's gravitational potential consistent with the latest observations. I also numerically calculate the Oort functions for different tracer populations of stars and compare them to a new analytical approximation. Additionally, I characterize the response of a kinematically warm disk to an elliptical m = 2 perturbation in detail. Overall, galpy consists of about 54,000 lines, including 23,000 lines of code in the module, 11,000 lines of test code, and about 20,000 lines of documentation. The test suite covers 99.6% of the code. galpy is available at http://github.com/jobovy/galpy with extensive documentation available at http://galpy.readthedocs.org/en/latest

  8. Galactic Building Blocks Seen Swarming Around Andromeda

    Science.gov (United States)

    2004-02-01

    Green Bank, WV - A team of astronomers using the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) has made the first conclusive detection of what appear to be the leftover building blocks of galaxy formation -- neutral hydrogen clouds -- swarming around the Andromeda Galaxy, the nearest large spiral galaxy to the Milky Way. This discovery may help scientists understand the structure and evolution of the Milky Way and all spiral galaxies. It also may help explain why certain young stars in mature galaxies are surprisingly bereft of the heavy elements that their contemporaries contain. Andromeda Galaxy This image depicts several long-sought galactic "building blocks" in orbit of the Andromeda Galaxy (M31). The newfound hydrogen clouds are depicted in a shade of orange (GBT), while gas that comprises the massive hydrogen disk of Andromeda is shown at high-resolution in blue (Westerbork Sythesis Radio Telescope). CREDIT: NRAO/AUI/NSF, WSRT (Click on Image for Larger Version) "Giant galaxies, like Andromeda and our own Milky Way, are thought to form through repeated mergers with smaller galaxies and through the accretion of vast numbers of even lower mass 'clouds' -- dark objects that lack stars and even are too small to call galaxies," said David A. Thilker of the Johns Hopkins University in Baltimore, Maryland. "Theoretical studies predict that this process of galactic growth continues today, but astronomers have been unable to detect the expected low mass 'building blocks' falling into nearby galaxies, until now." Thilker's research is published in the Astrophysical Journal Letters. Other contributors include: Robert Braun of the Netherlands Foundation for Research in Astronomy; Rene A.M. Walterbos of New Mexico State University; Edvige Corbelli of the Osservatorio Astrofisico di Arcetri in Italy; Felix J. Lockman and Ronald Maddalena of the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia; and Edward Murphy of the

  9. After the Fall: The RHESSI Legacy Archive

    Science.gov (United States)

    Schwartz, Richard A.; Zarro, Dominic M.; Tolbert, Anne K.

    2017-08-01

    Launched in 2002 the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) continues to observe the Sun with a nearly 50% duty cycle. During that time the instrument has recorded ~100,000 solar flares in energies from 4 keV to over 10 MeV.with durations of 10s to 1000s of seconds. However, for the reasons of the decline of the solar cycle, possible failure of the instrument, or the absence of funding, our operational phase will end someday. We describe here our plans to continue to serve this dataset in raw, processed, and analyzed forms to the worldwide solar community to continue our legacy of a stream of rich scientific results.We have and are providing a stream of quicklook lightcurves, spectra, and images that we mainly serve through a web interface as well as the data in raw form to be fully analyzed within our own branch of Solar Software written in IDL. We are in the process of creating higher quality images for flares in multiple energy bands on relevant timescales for those whose needs can be met without further processing. For users with IDL licenses we expect this software to be available far into the unknowable future. Together with a database of AIA cutouts during all SDO-era flares, along with software to recover saturated images by using the AIA diffraction fringes, these will be a highly used resource.We also are developing additional tools and databases that will increase the utility of RHESSI data to members of the community with and without either IDL licenses or full access to the RHESSI database. We will provide a database of RHESSI x-ray visibilities obtained during flares at a >4 second cadence over a broad range of detectable energies. With our IDL software those can be rendered as images for times and energies of nearly the analysts's choosing. And going beyond that we are converting our imaging procedures to the Python language to eliminate the need for an IDL license. We are also developing methods to allow the customization of these

  10. Nuclear legacy: Students of two atomic cities

    International Nuclear Information System (INIS)

    Petersen, Gary

    2002-01-01

    Full text: Battelle Memorial Institute operates the Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy. Within PNNL is the International Nuclear Safety Program (INSP) assigned to work on improving the safe operations of 67 Soviet-designed nuclear reactors in nine countries. One major mission of this program has been Chernobyl NPP activities, both for the operating plant, and for the Chernobyl Shelter. In conjunction with the activities at Chernobyl, several Battelle staff members have been living in Slavutych (the city closest to Chernobyl) for periods of up to two years. Through these personal relationships, Battelle began to take personal interest in students in Slavutych. In 1999 Battelle used private funding to support 20 students from Slavutych, Ukraine; and 20 students from Richland, Washington, U.S.A., in authoring a book called Nuclear Legacy: Students of Two Atomic Cities. This hard-bound book was researched, and written, entirely by these 40 13-to-15-year-old students. It is an amazing book, which describes the past, the present, and the future of two nuclear cities - Slavutych near Chernobyl, and Richland, near Hanford. It was written in two languages, with every article translated into both English and Ukrainian. It was published in June, 2000, and has now sold more than 2,600 copies in 14 countries. The book is primarily an educational publication designed to teach students how to write and publish a book on a sensitive subject - nuclear. It is not a political statement. However, the student researched and written articles do discuss politically sensitive nuclear topics in straightforward detail. The moving first hand accounts through the eyes of these young people of the 1986 Chernobyl nuclear accident, and interviews with scientists and engineers who worked on the 1940's Manhattan Project in the United States, make the book a unique collaboration on two nuclear cultures. What started as a one-semester project took a full

  11. Local meanings of a sport mega-event's legacies : Stories from a South African urban neighbourhood

    NARCIS (Netherlands)

    Waardenburg, Maikel; van den Bergh, Marjolein; van Eekeren, Frank

    2015-01-01

    Studies on sport mega-events and their legacies often seem only loosely connected to local experiences. Stories on sport mega-event legacy appear as a setting-the-scene or function as a reference to illustrate specific types of legacy. However, stories themselves are never the primary focus in these

  12. 31 CFR 357.20 - Securities account in Legacy Treasury Direct ®.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Securities account in Legacy Treasury Direct ®. 357.20 Section 357.20 Money and Finance: Treasury Regulations Relating to Money and Finance... Securities System (Legacy Treasury Direct) § 357.20 Securities account in Legacy Treasury Direct ®. (a...

  13. High-precision abundances of elements in Kepler LEGACY stars. Verification of trends with stellar age

    Science.gov (United States)

    Nissen, P. E.; Silva Aguirre, V.; Christensen-Dalsgaard, J.; Collet, R.; Grundahl, F.; Slumstrup, D.

    2017-12-01

    Context. A previous study of solar twin stars has revealed the existence of correlations between some abundance ratios and stellar age providing new knowledge about nucleosynthesis and Galactic chemical evolution. Aims: High-precision abundances of elements are determined for stars with asteroseismic ages in order to test the solar twin relations. Methods: HARPS-N spectra with signal-to-noise ratios S/N ≳ 250 and MARCS model atmospheres were used to derive abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, and Y in ten stars from the Kepler LEGACY sample (including the binary pair 16 Cyg A and B) selected to have metallicities in the range - 0.15 LTE iron abundances derived from Fe I and Fe II lines. Available non-LTE corrections were also applied when deriving abundances of the other elements. Results: The abundances of the Kepler stars support the [X/Fe]-age relations previously found for solar twins. [Mg/Fe], [Al/Fe], and [Zn/Fe] decrease by 0.1 dex over the lifetime of the Galactic thin disk due to delayed contribution of iron from Type Ia supernovae relative to prompt production of Mg, Al, and Zn in Type II supernovae. [Y/Mg] and [Y/Al], on the other hand, increase by 0.3 dex, which can be explained by an increasing contribution of s-process elements from low-mass AGB stars as time goes on. The trends of [C/Fe] and [O/Fe] are more complicated due to variations of the ratio between refractory and volatile elements among stars of similar age. Two stars with about the same age as the Sun show very different trends of [X/H] as a function of elemental condensation temperature Tc and for 16 Cyg, the two components have an abundance difference, which increases with Tc. These anomalies may be connected to planet-star interactions. Based on spectra obtained with HARPS-N@TNG under programme A33TAC_1.Tables 1 and 2 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc

  14. Celebrating the Life and Legacy of Rosa Parks

    Science.gov (United States)

    Stewart, Loraine

    2006-01-01

    In this article, the author presents the life and legacy of Rosa Parks. The author highlights four children's books that accurately portray Parks as an activist and acknowledge the broader context of her life's story--and the years of struggle of the black community against Jim Crow laws. The four children's books share Rosa Park's story in ways…

  15. Soil and Groundwater Characteristics of a Legacy Spill Site | Adoki ...

    African Journals Online (AJOL)

    The soil and groundwater of a legacy spill site in Eleme Local Government Authority Area of Rivers Stae were investigated. The general land use of the area within 1500m radius of the spill site is devoted to farming, fishing and hunting. The main crops grown include yams, cassava, maize, sugarcane, plantain, banana, ...

  16. Soil and Groundwater Characteristics of a Legacy Spill Site AKURO ...

    African Journals Online (AJOL)

    MICHAEL HORSFALL

    ABSTACT: The soil and groundwater of a legacy spill site in Eleme Local Government Authority Area of. Rivers Stae were investigated. The general land use of the area within 1500m radius of the spill site is devoted to farming, fishing and hunting. The main crops grown include yams, cassava, maize, sugarcane, plantain,.

  17. Legacy, resource mobilisation and the olympic movement | Girginov ...

    African Journals Online (AJOL)

    There has been a growing interest in legacies of the Olympic Games focusing on external tangible outcomes, such as the number of sport competitions, participants and jobs created. Little is still known about the equally valuable internal benefits to individuals and organisational capacities of national sport systems.

  18. Leaving a Legacy: Passing Montessori to the Next Generation

    Science.gov (United States)

    Loveless, Sylvia

    2012-01-01

    For each of the past 19 years, the American Montessori Society has chosen to recognize one Montessorian as an AMS Living Legacy. Recipients are honored at the AMS annual conference for their salient work or volunteerism in the Montessori field and their dedication and leadership that has made an impact on the AMS community. It seems fitting that…

  19. The impact of colonial legacies and globalization processes on ...

    African Journals Online (AJOL)

    In this paper, I postulate that forced migration in modern Africa is largely explained by factors deeply rooted in colonial legacies and the globalization process. For example, among the colonial historical factors someone may identify land alienation that still fuels conflicts in Zimbabwe, the colonial military doctrine based on ...

  20. The Troublesome Legacy of "Brown v. Board of Education"

    Science.gov (United States)

    López, Gerardo R.; Burciaga, Rebeca

    2014-01-01

    Purpose: This article reflects on the 60th anniversary of the "Brown v. Board of Education" Supreme Court decision while discussing the significant lessons learned from this and subsequent court decisions. Argument: In this article, we posit that a fundamentally different conversation surrounding the legacy of Brown is needed if we are…

  1. Bridging the gap between legacy services and Web Services

    DEFF Research Database (Denmark)

    Bissyandé, Tegawendé; Réveillère, Laurent; Bromberg, Yérom-David

    2010-01-01

    itself. In this paper, we introduce a generative language based approach for constructing wrappers to facilitate the migration of legacy service functionalities to Web Services. To this end, we have designed the Janus domain-specific language, which provides developers with a high-level way to describe...

  2. Forging Links between the Web and Legacy Systems.

    Science.gov (United States)

    Chapman, Noleen

    1998-01-01

    Discusses why information technology managers are exploring the economic and strategic advantages of Web technology and finding that legacy systems still have an important role. Presents benefits: centralized management, reduced cost of ownership, wide user access; models of Web-to-host access; the Citrix thin client model; and future of…

  3. BOKO HARAM IN NORTHERN NIGERIA: A MAUDUDIAN LEGACY ...

    African Journals Online (AJOL)

    Dean SPGS NAU

    colonialism and slavery” (2010, 168). Without question, colonial legacy contributed to the ... is the nature and mode of Shari'a implementation that is the issue. (2003, 144). This alludes to the influence of .... Syria, Iraq, Indonesia, Malaysia, Sri Lanka, Bangladesh, Nigeria,. South Africa, Kenya as well as elsewhere (2003, 533 ...

  4. Securing South Africa during the 2010 FIFA World Cup: Legacy ...

    African Journals Online (AJOL)

    Securing South Africa during the 2010 FIFA World Cup: Legacy implications for post-event safety and security. EC Perry, A Chunderduth, C Potgieter. Abstract. The trepidation over crime and safety concerns emerged as one of the main issues in relation to South Africa's hosting of the 2010 FIFA World Cup, prominent in the ...

  5. Paralympics 2012 Legacy: Accessible Housing and Disability Equality or Inequality?

    Science.gov (United States)

    Ahmed, Nadia

    2013-01-01

    The golden summer of sport is now over, but what is the legacy of London 2012 for disabled people? Nadia Ahmed, a disabled student, discusses the difficulties she has faced in finding accessible accommodation in London. She argues that while the Games are over, the United Kingdom still has lots of hurdles to leap when it comes to disability. The…

  6. Albert Schweitzer's Legacy for Education: Reverence for Life

    Science.gov (United States)

    Rud, A. G.

    2010-01-01

    "Albert Schweitzer's Legacy for Education" is the first book devoted to the study of the thought and deeds of Albert Schweitzer in relation to education. Schweitzer's life and work offer both inspiration and timely insights for educational thought and practice in the twenty-first century. Focusing on Schweitzer's central thought,…

  7. The Kemper History Project: From Historical Narrative to Institutional Legacy

    Science.gov (United States)

    Hunzicker, Jana

    2017-01-01

    An "institutional legacy" can be understood as knowledge, values, and shared experiences transmitted by or received from a college or university for the benefit of all who have taught, served, researched, and/or learned there. This article describes a year-long, collaborative writing project carried out by one university to chronicle two…

  8. An object-oriented framework for managing cooperating legacy databases

    NARCIS (Netherlands)

    Balsters, H; de Brock, EO

    2003-01-01

    We describe a general semantic framework for precise specification of so-called database federations. A database federation provides for tight coupling of a collection of heterogeneous legacy databases into a global integrated system. Our approach to database federation is based on the UML/OCL data

  9. Celebrating the Life and Legacy of Dr. John Hope Franklin

    Science.gov (United States)

    Harris, Robert L., Jr.; Levering-Lewis, David; French, John D.; Wharton, Clifton R., Jr.

    2009-01-01

    Dr. John Hope Franklin chronicled the experiences of African-Americans like no one before him, forcing America to recognize Black history as American history. His contributions were innumerable and his impact was abiding. In celebration of his life and legacy, the authors profile the celebrated scholar and activist, Dr. John Hope Franklin.

  10. SPITZER SAGE-SMC INFRARED PHOTOMETRY OF MASSIVE STARS IN THE SMALL MAGELLANIC CLOUD

    International Nuclear Information System (INIS)

    Bonanos, A. Z.; Lennon, D. J.; Massa, D. L.

    2010-01-01

    We present a catalog of 5324 massive stars in the Small Magellanic Cloud (SMC), with accurate spectral types compiled from the literature, and a photometric catalog for a subset of 3654 of these stars, with the goal of exploring their infrared properties. The photometric catalog consists of stars with infrared counterparts in the Spitzer SAGE-SMC survey database, for which we present uniform photometry from 0.3to24 μm in the UBVIJHK s +IRAC+MIPS24 bands. We compare the color-magnitude diagrams and color-color diagrams to those of stars in the Large Magellanic Cloud (LMC), finding that the brightest infrared sources in the SMC are also the red supergiants, supergiant B[e] (sgB[e]) stars, luminous blue variables, and Wolf-Rayet stars, with the latter exhibiting less infrared excess, the red supergiants being less dusty and the sgB[e] stars being on average less luminous. Among the objects detected at 24 μm in the SMC are a few very luminous hypergiants, four B-type stars with peculiar, flat spectral energy distributions, and all three known luminous blue variables. We detect a distinct Be star sequence, displaced to the red, and suggest a novel method of confirming Be star candidates photometrically. We find a higher fraction of Oe and Be stars among O and early-B stars in our SMC catalog, respectively, when compared to the LMC catalog, and that the SMC Be stars occur at higher luminosities. We estimate mass-loss rates for the red supergiants, confirming the correlation with luminosity even at the metallicity of the SMC. Finally, we confirm the new class of stars displaying composite A and F type spectra, the sgB[e] nature of 2dFS1804 and find the F0 supergiant 2dFS3528 to be a candidate luminous blue variable with cold dust.

  11. THE SPITZER INFRARED SPECTROGRAPH SURVEY OF PROTOPLANETARY DISKS IN ORION A. I. DISK PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. H. [Korea Astronomy and Space Science Institute (KASI), 776, Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Watson, Dan M.; Manoj, P.; Forrest, W. J. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Furlan, Elise [Infrared Processing and Analysis Center, Caltech, 770 S. Wilson Avenue, Pasadena, CA 91125 (United States); Najita, Joan [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Sargent, Benjamin [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Dr., Rochester, NY 14623 (United States); Hernández, Jesús [Centro de Investigaciones de Astronomía, Apdo. Postal 264, Mérida 5101-A (Venezuela, Bolivarian Republic of); Calvet, Nuria [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Adame, Lucía [Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, Av. Universidad S/N, San Nicolás de los Garza, Nuevo León, C.P. 66451, México (Mexico); Espaillat, Catherine [Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Megeath, S. T. [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft St., Toledo, OH 43606 (United States); Muzerolle, James, E-mail: quarkosmos@kasi.re.kr [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2016-09-01

    We present our investigation of 319 Class II objects in Orion A observed by Spitzer /IRS. We also present the follow-up observations of 120 of these Class II objects in Orion A from the Infrared Telescope Facility/SpeX. We measure continuum spectral indices, equivalent widths, and integrated fluxes that pertain to disk structure and dust composition from IRS spectra of Class II objects in Orion A. We estimate mass accretion rates using hydrogen recombination lines in the SpeX spectra of our targets. Utilizing these properties, we compare the distributions of the disk and dust properties of Orion A disks with those of Taurus disks with respect to position within Orion A (Orion Nebular Cluster [ONC] and L1641) and with the subgroups by the inferred radial structures, such as transitional disks (TDs) versus radially continuous full disks (FDs). Our main findings are as follows. (1) Inner disks evolve faster than the outer disks. (2) The mass accretion rates of TDs and those of radially continuous FDs are statistically significantly displaced from each other. The median mass accretion rate of radially continuous disks in the ONC and L1641 is not very different from that in Taurus. (3) Less grain processing has occurred in the disks in the ONC compared to those in Taurus, based on analysis of the shape index of the 10 μ m silicate feature ( F {sub 11.3}/ F {sub 9.8}). (4) The 20–31 μ m continuum spectral index tracks the projected distance from the most luminous Trapezium star, θ {sup 1} Ori C. A possible explanation is UV ablation of the outer parts of disks.

  12. THE SPITZER INFRARED SPECTROGRAPH SURVEY OF T TAURI STARS IN TAURUS

    International Nuclear Information System (INIS)

    Furlan, E.; Luhman, K. L.; Espaillat, C.

    2011-01-01

    We present 161 Spitzer Infrared Spectrograph (IRS) spectra of T Tauri stars and young brown dwarfs in the Taurus star-forming region. All of the targets were selected based on their infrared excess and are therefore surrounded by protoplanetary disks; they form the complete sample of all available IRS spectra of T Tauri stars with infrared excesses in Taurus. We also present the IRS spectra of seven Class 0/I objects in Taurus to complete the sample of available IRS spectra of protostars in Taurus. We use spectral indices that are not significantly affected by extinction to distinguish between envelope- and disk-dominated objects. Together with data from the literature, we construct spectral energy distributions for all objects in our sample. With spectral indices derived from the IRS spectra we infer disk properties such as dust settling and the presence of inner disk holes and gaps. We find a transitional disk frequency, which is based on objects with unusually large 13-31 μm spectral indices indicative of a wall surrounding an inner disk hole, of about 3%, and a frequency of about 20% for objects with unusually large 10 μm features, which could indicate disk gaps. The shape and strength of the 10 μm silicate emission feature suggests weaker 10 μm emission and more processed dust for very low mass objects and brown dwarfs (spectral types M6-M9). These objects also display weaker infrared excess emission from their disks, but do not appear to have more settled disks than their higher-mass counterparts. We find no difference for the spectral indices and properties of the dust between single and multiple systems.

  13. MODELS OF THE η CORVI DEBRIS DISK FROM THE KECK INTERFEROMETER, SPITZER, AND HERSCHEL

    Energy Technology Data Exchange (ETDEWEB)

    Lebreton, J.; Beichman, C.; Millan-Gabet, R. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Bryden, G.; Mennesson, B. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91107 (United States); Defrère, D. [Department of Astronomy, University of Arizona, 993 N. Cherry Avenue, Tucson, AZ, 85721 (United States); Boccaletti, A., E-mail: lebretoj@gmail.com [LESIA, Observatoire de Paris, CNRS, University Pierre et Marie Curie Paris 6 and University Denis Diderot Paris 7, 5 place Jules Janssen, F-92195 Meudon (France)

    2016-02-01

    Debris disks are signposts of analogs to small-body populations of the solar system, often, however, with much higher masses and dust production rates. The disk associated with the nearby star η Crv is especially striking, as it shows strong mid- and far-infrared excesses despite an age of ∼1.4 Gyr. We undertake constructing a consistent model of the system that can explain a diverse collection of spatial and spectral data. We analyze Keck Interferometer Nuller measurements and revisit Spitzer and additional spectrophotometric data, as well as resolved Herschel images, to determine the dust spatial distribution in the inner exozodi and in the outer belt. We model in detail the two-component disk and the dust properties from the sub-AU scale to the outermost regions by fitting simultaneously all measurements against a large parameter space. The properties of the cold belt are consistent with a collisional cascade in a reservoir of ice-free planetesimals at 133 AU. It shows marginal evidence for asymmetries along the major axis. KIN enables us to establish that the warm dust consists of a ring that peaks between 0.2 and 0.8 AU. To reconcile this location with the ∼400 K dust temperature, very high albedo dust must be invoked, and a distribution of forsterite grains starting from micron sizes satisfies this criterion, while providing an excellent fit to the spectrum. We discuss additional constraints from the LBTI and near-infrared spectra, and we present predictions of what James Webb Space Telescope can unveil about this unusual object and whether it can detect unseen planets.

  14. DEEP JHKs AND SPITZER IMAGING OF FOUR ISOLATED MOLECULAR CLOUD CORES

    International Nuclear Information System (INIS)

    Chapman, Nicholas L.; Mundy, Lee G.

    2009-01-01

    We present observations in eight wavebands from 1.25 to 24 μm of four dense cores: L204C-2, L1152, L1155C-2, and L1228. Our goals are to study the young stellar object (YSO) population of these cores and to measure the mid-infrared extinction law. With our combined near-infrared and Spitzer photometry, we classify each source in the cores as, among other things, background stars, galaxies, or embedded YSOs. L1152 contains three YSOs and L1228 has seven, but neither L204C-2 nor L1155C-2 appear to contain any YSOs. We estimate an upper limit of 7 x 10 -5 to 5 x 10 -4 L sun for any undiscovered YSOs in our cores. We also compute the line-of-sight extinction law toward each background star. These measurements are averaged spatially, to create χ 2 maps of the changes in the mid-infrared extinction law throughout our cores, and also in different ranges of extinction. From the χ 2 maps, we identify two small regions in L1152 and L1228 where the outflows in those cores appear to be destroying the larger dust grains, thus altering the extinction law in those regions. On average, however, our extinction law is relatively flat from 3.6 to 24 μm for all ranges of extinction and in all four cores. From 3.6 to 8 μm, this law is consistent with a dust model that includes larger dust grains than the diffuse interstellar medium, which suggests grain growth has occurred in our cores. At 24 μm, our extinction law is two to four times higher than predicted by dust models. However, it is similar to other empirical measurements.

  15. Dust in a Type Ia Supernova Progenitor: Spitzer Spectroscopy of Kepler's Supernova Remnant

    Science.gov (United States)

    Williams, Brian J.; Borkowski, Kazimierz; Reynolds, Stephen P.; Ghavamian, Parviz; Blair, William P.; Long, Knox S.; Sankrit, Ravi

    2012-01-01

    Characterization of the relatively poorly-understood progenitor systems of Type Ia supernovae is of great importance in astrophysics, particularly given the important cosmological role that these supernovae play. Kepler's Supernova Remnant, the result of a Type Ia supernova, shows evidence for an interaction with a dense circumstellar medium (CSM), suggesting a single-degenerate progenitor system. We present 7.5-38 micron IR spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 micron, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the AGB stage of evolution, and imply an oxygen-rich chemistry. In addition to silicate dust, a second component, possibly carbonaceous dust, is necessary to account for the short-wavelength IRS and IRAC data. This could imply a mixed chemistry in the atmosphere of the progenitor system. However, non-spherical metallic iron inclusions within silicate grains provide an alternative solution. Models of collisionally-heated dust emission from fast shocks (> 1000 km/s) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are approx 80-100 K, but fail to account for the highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km/s) into moderate density material (n(sub o) approx 50-100 / cubic cm) are the only viable source of heating for this hottest dust. We confirm the finding of an overall density gradient, with densities in the north being an order of magnitude greater than those in the south.

  16. A new look at Spitzer primary transit observations of the exoplanet HD 189733b

    Energy Technology Data Exchange (ETDEWEB)

    Morello, G.; Waldmann, I. P.; Tinetti, G.; Howarth, I. D. [Department of Physics and Astronomy, University College London, Gower Street, WC1E6BT (United Kingdom); Peres, G. [Dipartimento di Fisica, Università degli Studi di Palermo, via Archirafi I-90123, Italy. (Italy); Micela, G., E-mail: giuseppe.morello.11@ucl.ac.uk [Dipartimento di Fisica e Chimica (previously Dipartimento di Fisica), Specola Universitaria, Università degli Studi di Palermo, Piazza del Parlamento 1 I-90123 (Italy)

    2014-05-01

    Blind source separation techniques are used to reanalyze two exoplanetary transit light curves of the exoplanet HD 189733b recorded with the IR camera IRAC on board the Spitzer Space Telescope at 3.6 μm during the 'cold' era. These observations, together with observations at other IR wavelengths, are crucial to characterize the atmosphere of the planet HD 189733b. Previous analyses of the same data sets reported discrepant results, hence the necessity of the reanalyses. The method we used here is based on the Independent Component Analysis (ICA) statistical technique, which ensures a high degree of objectivity. The use of ICA to detrend single photometric observations in a self-consistent way is novel in the literature. The advantage of our reanalyses over previous work is that we do not have to make any assumptions on the structure of the unknown instrumental systematics. Such 'admission of ignorance' may result in larger error bars than reported in the literature, up to a factor 1.6. This is a worthwhile tradeoff for much higher objectivity, necessary for trustworthy claims. Our main results are (1) improved and robust values of orbital and stellar parameters, (2) new measurements of the transit depths at 3.6 μm, (3) consistency between the parameters estimated from the two observations, (4) repeatability of the measurement within the photometric level of ∼2 × 10{sup –4} in the IR, and (5) no evidence of stellar variability at the same photometric level within one year.

  17. SEDS: THE SPITZER EXTENDED DEEP SURVEY. SURVEY DESIGN, PHOTOMETRY, AND DEEP IRAC SOURCE COUNTS

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, M. L. N.; Willner, S. P.; Fazio, G. G.; Huang, J.-S.; Hernquist, L.; Hora, J. L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Arendt, R. [Observational Cosmology Laboratory, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Barmby, P. [University of Western Ontario, London, ON N6A 3K7 (Canada); Barro, G.; Faber, S.; Guhathakurta, P. [University of California Observatories/Lick Observatory and Department of Astronomy and Astrophysics University of California Santa Cruz, 1156 High St., Santa Cruz, CA 95064 (United States); Bell, E. F. [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States); Bouwens, R. [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Cattaneo, A. [Aix Marseille Universite, CNRS, Laboratoire d' Astrophysique de Marseille, UMR 7326, F-13388, Marseille (France); Croton, D. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218 Hawthorn, VIC 3122 (Australia); Dave, R. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Dunlop, J. S. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Egami, E. [Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States); Finlator, K. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, CK-2100 Copenhagen O (Denmark); Grogin, N. A., E-mail: mashby@cfa.harvard.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2013-05-20

    The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg{sup 2} to a depth of 26 AB mag (3{sigma}) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 {mu}m. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 {+-} 1.0 and 4.4 {+-} 0.8 nW m{sup -2} sr{sup -1} at 3.6 and 4.5 {mu}m to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component.

  18. A Spitzer search for transits of radial velocity detected super-Earths

    International Nuclear Information System (INIS)

    Kammer, J. A.; Knutson, H. A.; Desert, J.-M.; Howard, A. W.; Laughlin, G. P.; Fortney, J. J.; Deming, D.; Todorov, K. O.; Agol, E.; Burrows, A.; Showman, A. P.; Lewis, N. K.

    2014-01-01

    Unlike hot Jupiters or other gas giants, super-Earths are expected to have a wide variety of compositions, ranging from terrestrial bodies like our own to more gaseous planets like Neptune. Observations of transiting systems, which allow us to directly measure planet masses and radii and constrain atmospheric properties, are key to understanding the compositional diversity of the planets in this mass range. Although Kepler has discovered hundreds of transiting super-Earth candidates over the past 4 yr, the majority of these planets orbit stars that are too far away and too faint to allow for detailed atmospheric characterization and reliable mass estimates. Ground-based transit surveys focus on much brighter stars, but most lack the sensitivity to detect planets in this size range. One way to get around the difficulty of finding these smaller planets in transit is to start by choosing targets that are already known to host super-Earth sized bodies detected using the radial velocity (RV) technique. Here we present results from a Spitzer program to observe six of the most favorable RV-detected super-Earth systems, including HD 1461, HD 7924, HD 156668, HIP 57274, and GJ 876. We find no evidence for transits in any of their 4.5 μm flux light curves, and place limits on the allowed transit depths and corresponding planet radii that rule out even the most dense and iron-rich compositions for these objects. We also observed HD 97658, but the observation window was based on a possible ground-based transit detection that was later ruled out; thus the window did not include the predicted time for the transit detection recently made by the Microvariability and Oscillations of Stars space telescope.

  19. Detection of Planetary Emission from the Exoplanet TrES-2 Using Spitzer/IRAC

    Science.gov (United States)

    Donovan, Francis T.; Charbonneau, David; Harrington, Joseph; Madhusudhan, N.; Seager, Sara; Deming, Drake; Knutson, Heather A.

    2010-01-01

    We present here the results of our observations of TrES-2 using the Infrared Array Camera on Spitzer. We monitored this transiting system during two secondary eclipses, when the planetary emission is blocked by the star. The resulting decrease in flux is 0.127% +/- 0.021%, 0.230% +/- 0.024%, 0.199% +/- 0.054%, and 0.359% +/- 0.060% at 3.6 microns, 4.5 microns, 5.8 microns, and 8.0 microns, respectively. We show that three of these flux contrasts are well fit by a blackbody spectrum with T(sub eff) = 1500 K, as well as by a more detailed model spectrum of a planetary atmosphere. The observed planet-to-star flux ratios in all four lRAC channels can be explained by models with and without a thermal inversion in the atmosphere of TrES-2, although with different atmospheric chemistry. Based on the assumption of thermochemical equilibrium, the chemical composition of the inversion model seems more plausible, making it a more favorable scenario. TrES-2 also falls in the category of highly irradiated planets which have been theoretically predicted to exhibit thermal inversions. However, more observations at infrared and visible wavelengths would be needed to confirm a thermal inversion in this system. Furthermore, we find that the times of the secondary eclipses are consistent with previously published times of transit and the expectation from a circular orbit. This implies that TrES-2 most likely has a circular orbit, and thus does not obtain additional thermal energy from tidal dissipation of a non-zero orbital eccentricity, a proposed explanation for the large radius of this planet. Key words: eclipses - infrared: stars - planetary systems - stars: individual (OSC 03549-02811) - techniques: photometric

  20. PHOTOMETRIC MONITORING OF THE COLDEST KNOWN BROWN DWARF WITH THE SPITZER SPACE TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Esplin, T. L.; Luhman, K. L. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Cushing, M. C.; Hardegree-Ullman, K. K.; Trucks, J. L.; Schneider, A. C. [Department of Physics and Astronomy, The University of Toledo, OH 43606 (United States); Burgasser, A. J., E-mail: taran.esplin@psu.edu [Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States)

    2016-11-20

    Because WISE J085510.83-071442.5 (hereafter WISE 0855-0714) is the coldest known brown dwarf (∼250 K) and one of the Sun’s closest neighbors (2.2 pc), it offers a unique opportunity to study a planet-like atmosphere in an unexplored regime of temperature. To detect and characterize inhomogeneities in its atmosphere (e.g., patchy clouds, hot spots), we have performed time-series photometric monitoring of WISE 0855-0714 at 3.6 and 4.5 μ m with the Spitzer Space Telescope during two 23 hr periods that were separated by several months. For both bands, we have detected variability with peak-to-peak amplitudes of 4%–5% and 3%–4% in the first and second epochs, respectively. The light curves are semiperiodic in the first epoch for both bands, but they are more irregular in the second epoch. Models of patchy clouds have predicted a large increase in mid-infrared (mid-IR) variability amplitudes (for a given cloud covering fraction) with the appearance of water ice clouds at T {sub eff} < 375 K, so if such clouds are responsible for the variability of WISE 0855-0714, then its small amplitudes of variability indicate a very small deviation in cloud coverage between hemispheres. Alternatively, the similarity in mid-IR variability amplitudes between WISE 0855-0714 and somewhat warmer T and Y dwarfs may suggest that they share a common origin for their variability (i.e., not water clouds). In addition to our variability data, we have examined other constraints on the presence of water ice clouds in the atmosphere of WISE 0855-0714, including the recent mid-IR spectrum from Skemer et al. (2016). We find that robust evidence of such clouds is not yet available.

  1. Asteroid (16) Psyche: Evidence for a silicate regolith from spitzer space telescope spectroscopy

    Science.gov (United States)

    Landsman, Zoe A.; Emery, Joshua P.; Campins, Humberto; Hanuš, Josef; Lim, Lucy F.; Cruikshank, Dale P.

    2018-04-01

    Asteroid (16) Psyche is a unique, metal-rich object belonging to the "M" taxonomic class. It may be a remnant protoplanet that has been stripped of most silicates by a hit-and-run collision. Because Psyche offers insight into the planetary formation process, it is the target of NASA's Psyche mission, set to launch in 2023. In order to constrain Psyche's surface properties, we have carried out a mid-infrared (5-14 μm) spectroscopic study using data collected with the Spitzer Space Telescope's Infrared Spectrograph. Our study includes two observations covering different rotational phases. Using thermophysical modeling, we find that Psyche's surface is smooth and likely has a thermal inertia Γ = 5-25 J/m2/K/s1/2 and bolometric emissivity ɛ = 0.9, although a scenario with ɛ = 0.7 and thermal inertia up to 95 J/m2/K/s1/2 is possible if Psyche is somewhat larger than previously determined. The smooth surface is consistent with the presence of a metallic bedrock, which would be more ductile than silicate bedrock, and thus may not readily form boulders upon impact events. From comparisons with laboratory spectra of silicate and meteorite powders, Psyche's 7-14 μm emissivity spectrum is consistent with the presence of fine-grained (< 75 μm) silicates on Psyche's surface. We conclude that Psyche is likely covered in a fine silicate regolith, which may also contain iron grains, overlying an iron-rich bedrock.

  2. Radio Telescopes Reveal Unseen Galactic Cannibalism

    Science.gov (United States)

    2008-06-01

    Radio-telescope images have revealed previously-unseen galactic cannibalism -- a triggering event that leads to feeding frenzies by gigantic black holes at the cores of galaxies. Astronomers have long suspected that the extra-bright cores of spiral galaxies called Seyfert galaxies are powered by supermassive black holes consuming material. However, they could not see how the material is started on its journey toward the black hole. Optical/Radio Comparison Visible-light (left) and radio (right) image of galaxy pair: Radio image shows gas streaming between galaxies. CREDIT: Kuo et al., NRAO/AUI/NSF Click on image for more graphics. One leading theory said that Seyfert galaxies have been disturbed by close encounters with neighboring galaxies, thus stirring up their gas and bringing more of it within the gravitational reach of the black hole. However, when astronomers looked at Seyferts with visible-light telescopes, only a small fraction showed any evidence of such an encounter. Now, new images of hydrogen gas in Seyferts made using the National Science Foundation's Very Large Array (VLA) radio telescope show the majority of them are, in fact, disturbed by ongoing encounters with neighbor galaxies. "The VLA lifted the veil on what's really happening with these galaxies," said Cheng-Yu Kuo, a graduate student at the University of Virginia. "Looking at the gas in these galaxies clearly showed that they are snacking on their neighbors. This is a dramatic contrast with their appearance in visible starlight," he added. The effect of the galactic encounters is to send gas and dust toward the black hole and produce energy as the material ultimately is consumed. Black holes, concentrations of matter so dense that not even light can escape their gravitational pull, reside at the cores of many galaxies. Depending on how rapidly the black hole is eating, the galaxy can show a wide range of energetic activity. Seyfert galaxies have the mildest version of this activity, while

  3. CANDELS: The Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey

    Science.gov (United States)

    Grogin, Norman A.; Koekemoer, anton M.; Faber, S. M.; Ferguson, Henry C.; Kocevski, Dale D.; Riess, Adam G.; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; hide

    2011-01-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, from z approx. 8 - 1.5. It will image > 250,000 distant galaxies using three separate cameras on the Hubble Space Tele8cope, from the mid-UV to near-IR, and will find and measure Type Ia supernovae beyond z > 1.5 to test their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10(exp 9) solar mass to z approx. 2, reaching the knee of the UV luminosity function of galaxies to z approx. 8. The survey covers approximately 800 square arc minutes and is divided into two parts. The CANDELS/Deep survey (5(sigma) point-source limit H =27.7mag) covers approx. 125 square arcminutes within GOODS-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (EGS, COSMOS, and UDS) and covers the full area to a 50(sigma) point-source limit of H ? or approx. = 27.0 mag. Together with the Hubble Ultradeep Fields, the strategy creates a three-tiered "wedding cake" approach that has proven efficient for extragalactic surveys. Data from the survey are non-proprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design.

  4. CANDELS: THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Grogin, Norman A.; Ferguson, Henry C.; Koekemoer, Anton M.; Brown, Thomas M.; Casertano, Stefano [Space Telescope Science Institute, Baltimore, MD (United States); Kocevski, Dale D.; Faber, S. M. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States); Riess, Adam G. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD (United States); Acquaviva, Viviana [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ (United States); Alexander, David M. [Department of Physics, Durham University, Durham (United Kingdom); Almaini, Omar [The School of Physics and Astronomy, University of Nottingham, Nottingham (United Kingdom); Ashby, Matthew L. N. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Barden, Marco [Institute of Astro- and Particle Physics, University of Innsbruck, Innsbruck (Austria); Bell, Eric F. [Department of Astronomy, University of Michigan, Ann Arbor, MI (United States); Bournaud, Frederic [CEA-Saclay/DSM/DAPNIA/Service d' Astrophysique, Gif-sur-Yvette (France); Caputi, Karina I. [Institute for Astronomy, University of Edinburgh, Edinburgh (United Kingdom); Cassata, Paolo [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Castellano, Marco [INAF, Osservatorio Astronomico di Roma, Rome (Italy); Challis, Peter [Harvard College Observatory, Cambridge, MA (United States); Chary, Ranga-Ram [U.S. Planck Data Center, California Institute of Technology, Pasadena, CA (United States); and others

    2011-12-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8-1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the mid-ultraviolet to the near-infrared, and will find and measure Type Ia supernovae at z > 1.5 to test their accuracy as standardizable candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10{sup 9} M{sub Sun} to z Almost-Equal-To 2, reaching the knee of the ultraviolet luminosity function of galaxies to z Almost-Equal-To 8. The survey covers approximately 800 arcmin{sup 2} and is divided into two parts. The CANDELS/Deep survey (5{sigma} point-source limit H = 27.7 mag) covers {approx}125 arcmin{sup 2} within Great Observatories Origins Deep Survey (GOODS)-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (Extended Groth Strip, COSMOS, and Ultra-deep Survey) and covers the full area to a 5{sigma} point-source limit of H {approx}> 27.0 mag. Together with the Hubble Ultra Deep Fields, the strategy creates a three-tiered 'wedding-cake' approach that has proven efficient for extragalactic surveys. Data from the survey are nonproprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design. The Hubble data processing and products are described in a companion paper.

  5. Scale and legacy controls on catchment nutrient export regimes

    Science.gov (United States)

    Howden, N. J. K.; Burt, T.; Worrall, F.

    2017-12-01

    Nutrient dynamics in river catchments are complex: water and chemical fluxes are highly variable in low-order streams, but this variability declines as fluxes move through higher-order reaches. This poses a major challenge for process understanding as much effort is focussed on long-term monitoring of the main river channel (a high-order reach), and therefore the data available to support process understanding are predominantly derived from sites where much of the transient response of nutrient export is masked by the effect of averaging over both space and time. This may be further exacerbated at all scales by the accumulation of legacy nutrient sources in soils, aquifers and pore waters, where historical activities have led to nutrient accumulation where the catchment system is transport limited. Therefore it is of particular interest to investigate how the variability of nutrient export changes both with catchment scale (from low to high-order catchment streams) and with the presence of legacy sources, such that the context of infrequent monitoring on high-order streams can be better understood. This is not only a question of characterising nutrient export regimes per se, but also developing a more thorough understanding of how the concepts of scale and legacy may modify the statistical characteristics of observed responses across scales in both space and time. In this paper, we use synthetic data series and develop a model approach to consider how space and timescales combine with impacts of legacy sources to influence observed variability in catchment export. We find that: increasing space and timescales tend to reduce the observed variance in nutrient exports, due to an increase in travel times and greater mixing, and therefore averaging, of sources; increasing the influence of legacy sources inflates the variance, with the level of inflation dictated by the residence time of the respective sources.

  6. The MopraCO Galactic Survey

    Science.gov (United States)

    Romano, Domenico; Burton, Michael; Braiding, Catherine; Molinari, Sergio; Ashley, Michael

    2017-11-01

    The MopraCO project (see also Burton et al., 2013, Braiding et al., 2015, Rebolledo et al., 2016) is a CO J=1-0 line survey across the 4th Quadrant of the Milky Way, performed using the 22 m diameter single dish Mopra telescope in Australia. It includes the three main CO molecule isotopologues (12CO , 13CO and C18O) and more than 100 square degrees have been surveyed, spanning from l=265deg to +10deg and b= ± 0.5deg, covering also the Carina complex and the Central Molecular Zone, and extending beyond b= ± 0.5o in several regions. The final plan is to cover from l=265deg to +10deg and b= ± 1deg. The use of the 8 GHz-wide UNSW-MOPS spectrometer and the fast mode of on-the-fly mapping, developed for the Mopra telescope, permits us to reduce the cycle time to 1/4 of a second. Compared with the previous Dame et al. 2001 CO survey of the Southern Galactic plane the MopraCO spectral and angular resolution of 0.1 km/s and 0.6' are an order of magnitude better. This permits us to improve the model of our Galaxy, showing the spirals structures with unprecedented details, in particular in the inner regions where the tracers of spiral arm tangents show an offset from the mid-arms that is matched by maser data, while the real structure of the innermost region remains difficult to define. Furthermore, the 12CO/13CO line ratios are found to be higher in the diffuse gas outside the GMC complexes than inside them, opening new hypothesis on the Xco factor used to estimate the masses of the molecular clouds. Providing a detailed large scale third dimension, across the Southern Galaxy in the wide range of velocity (-500 to 450 km/s), the combination of this survey with the other ones will help to investigate the "dark" gas fraction not traced by the CO, better characterise the evolution of the molecular clouds and of the dense core inside them, giving more insights on the early stages of massive star formation. In particular, in the direction toward the galactic longitude 332 at a

  7. Manganese abundances in Galactic bulge red giants

    Science.gov (United States)

    Barbuy, B.; Hill, V.; Zoccali, M.; Minniti, D.; Renzini, A.; Ortolani, S.; Gómez, A.; Trevisan, M.; Dutra, N.

    2013-11-01

    Context. Manganese is mainly produced in type II SNe during explosive silicon burning, in incomplete Si-burning regions, and depends on several nucleosynthesis environment conditions, such as mass cut between the matter ejected and falling back onto the remnant, electron and neutron excesses, mixing fallback, and explosion energy. Manganese is also produced in type Ia SNe. Aims: The aim of this work is the study of abundances of the iron-peak element Mn in 56 bulge giants, among which 13 are red clump stars. Four bulge fields along the minor axis are inspected. The study of abundances of Mn-over-Fe as a function of metallicity in the Galactic bulge may shed light on its production mechanisms. Methods: High-resolution spectra were obtained using the FLAMES+UVES spectrograph on the Very Large Telescope. The spectra were obtained within a program to observe 800 stars using the GIRAFFE spectrograph, together with the present UVES spectra. Results: We aim at identifying the chemical evolution of manganese, as a function of metallicity, in the Galactic bulge. We find [Mn/Fe] ~ -0.7 at [Fe/H] ~ -1.3, increasing to a solar value at metallicities close to solar, and showing a spread around - 0.7 ≲ [Fe/H] ≲ -0.2, in good agreement with other work on Mn in bulge stars. There is also good agreement with chemical evolution models. We find no clear difference in the behaviour of the four bulge fields. Whereas [Mn/Fe] vs. [Fe/H] could be identified with the behaviour of the thick disc stars, [Mn/O] vs. [O/H] has a behaviour running parallel, at higher metallicities, compared to thick disc stars, indicating that the bulge enrichment might have proceeded differently from that of the thick disc. Observations collected at the European Southern Observatory, Paranal, Chile (ESO programmes 71.B-0617A, 73.B0074A, and GTO 71.B-0196).Tables 1-6 and Figs. 1-6 are available in electronic form at http://www.aanda.org

  8. Environmental properties related to active galactic nuclei

    Science.gov (United States)

    Manzer, Lianne H.

    There continues to be significant controversy regarding the mechanisms responsible for the initiation of activity in galactic nuclei. It is well understood that the non-thermal energy produced by an AGN is due to accretion onto a supermassive black hole. It has not yet been determined, however, what leads particular galaxies to become active. An accurate exploration into what triggers an AGN demands an analysis of a large sample of galaxies across a diverse set of environments. In this work, we investigate possible environmental influences by carrying out a statistical investigation of galaxy groups. Using the catalogue of Yang et al. (2007), in which groups of galaxies containing between 2 and 20 members with redshifts between 0.01 -- 0.20 were taken from the Sloan Digital Sky Survey, we investigate the fraction of active galactic nuclei (AGN) within these groups and compare it to the sample of isolated galaxies also obtained from Yang et al. (2007). After correcting our spectroscopic data for extinction and underlying stellar absorption, we classify the galaxy sample using relevant emission-line ratios. We propose an alternate method for classifying emission-line galaxies, including AGN, which builds upon standard diagnostic utilities used for optical classification and includes uncertainties. Such classification probabilities offer a more robust and consistent method of investigating the effect of group environments with galaxy type. We find our sample to be a fair representation of the local universe by comparing the luminosity function of our entire data set to that of Blanton et al. (2001), Blanton et al. (2003b), and Montero-Dorta & Prada (2009). The evidence also suggests that the luminosity function of galaxies differs between isolated galaxies and galaxies in groups. We find a significant increase in the fraction of AGNs identified in grouped environments. On the other hand, we find a higher fraction of starforming galaxies within isolated systems. We

  9. The dynamics of dense galactic nuclei

    Science.gov (United States)

    Lee, Man Hoi

    In this thesis, two topics on the dynamics of dense galactic nuclei are studied. They are relevant to the formation of massive black holes and the observations of several nearby galactic nuclei. An overview of the observations is given in Chapter 1. In Chapter 2, the dynamical evolution of dense clusters of compact stars is studied. The formation of binaries and their subsequent merging by gravitational radiation emission is important to the evolution of such clusters. Aarseth's NBODY5 N-body simulation code, which is modified to include these processes, is used to simulate small N clusters with different initial velocity dispersions. The initial evolution is similar to previous results from Fokker-Planck simulations and shows orderly formation of heavy objects. However, the late evolution shows runaway growth for the most massive object in the cluster. We present arguments to show that merger by gravitational radiation (and possibly hydrodynamic merger of normal stars) is expected to be unstable to runaway growth. These results suggest that a seed massive black hole can be formed by runaway growth in a dense cluster of compact stars. In Chapter 3, the effects of stellar encounters on rotating stellar systems with central massive black holes are studied. For axisymmetric stellar systems with distribution functions that depend only on the energy E and the angular momentum about one axis Jx, the steady-state stellar distribution is found by directly integrating the Fokker-Planck equation in E, J subx) space. Two sets of models with simple assumptions about the loss cone in phase space (due to loss of stars to the central black hole) are presented: the loss cone in the Jx direction is either ignored or completely empty. We find that the depletion of stars due to an empty loss cone is significant. Density and kinematic profiles are also presented. The ratio of rotation velocity to velocity dispersion, V/sigma at small radii is higher than that of the background

  10. Interplay between Dark Matter and Galactic Structure in Disk and ...

    Indian Academy of Sciences (India)

    2016-01-27

    ) of an axially symmetric time-independent galactic model with a spherical central nucleus, and a flat biaxial oblate dark matter halo component. In particular, we try to reveal the influence of the fractional portion of dark matter ...

  11. Relations between the galactic evolution and the stellar evolution

    International Nuclear Information System (INIS)

    Audouze, J.

    1984-01-01

    After a quick definition of the galactic evolution and a summary of the basic ingredients (namely the abundances of the chemical elements observed in different astrophysical sites), the parameters directly related to the stellar evolution which govern the galactic evolution are outlined. They are the rates of star formation, the initial mass functions and the various nucleosynthetic yields. The 'classical' models of chemical evolution of galaxies are then briefly recalled. Finally, attention is drawn to three recent contributions concerning both the galactic evolution and the stellar evolution. They are (i) some prediction of the rate of star formation for low mass stars made from the planetary nebula abundance distribution (ii) the chemical evolution of C, O and Fe and (iii) the chemical evolution of the galactic interstellar medium. (Auth.)

  12. Galactic Black Hole Binaries: High-Energy Radiation

    National Research Council Canada - National Science Library

    Grove, J. E; Grindlay, J. E; Harmon, B. A; Hua, X. -M; Kazanas, D; McConnell, M

    1997-01-01

    Observations of galactic black hole candidates made by the instruments aboard the Compton GRO in the hard X-ray and gamma-ray bands have significantly enhanced our knowledge of the emission properties of these objects...

  13. PHYSICAL PROPERTIES, STAR FORMATION, AND ACTIVE GALACTIC NUCLEUS ACTIVITY IN BALMER BREAK GALAXIES AT 0 < z < 1

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Tello, J.; Donzelli, C. [IATE, Observatorio Astronomico de Cordoba, Universidad Nacional de Cordoba (Argentina); Padilla, N. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile (Chile); Fujishiro, N.; Yoshikawa, T. [Koyama Astronomical Observatory, Kyoto Sangyo University (Japan); Hanami, H. [Physics Section, Iwate University (Japan); Hatsukade, B., E-mail: jdiazt@oac.uncor.edu [Department of Astronomy, Kyoto University (Japan)

    2013-07-01

    We present a spectroscopic study with the derivation of the physical properties of 37 Balmer break galaxies, which have the necessary lines to locate them in star-forming-active galactic nuclei (AGNs) diagnostic diagrams. These galaxies span a redshift range from 0.045 to 0.93 and are somewhat less massive than similar samples of previous works. The studied sample has multiwavelength photometric data coverage from the ultraviolet to mid-infrared (MIR) Spitzer bands. We investigate the connection between star formation and AGN activity via optical, mass-excitation (MEx), and MIR diagnostic diagrams. Through optical diagrams, 31 (84%) star-forming galaxies, two (5%) composite galaxies, and three (8%) AGNs were classified, whereas from the MEx diagram only one galaxy was classified as AGN. A total of 19 galaxies have photometry available in all the IRAC/Spitzer bands. Of these, three AGN candidates were not classified as AGN in the optical diagrams, suggesting they are dusty/obscured AGNs, or that nuclear star formation has diluted their contributions. By fitting the spectral energy distribution of the galaxies, we derived the stellar masses, dust reddening E(B - V), ages, and UV star formation rates (SFRs). Furthermore, the relationship between SFR surface density ({Sigma}{sub SFR}) and stellar mass surface density per time unit ({Sigma}{sub M{sub */{tau}}}) as a function of redshift was investigated using the [O II] {lambda}3727, 3729, H{alpha} {lambda}6563 luminosities, which revealed that both quantities are larger for higher redshift galaxies. We also studied the SFR and specific SFR (SSFR) versus stellar mass and color relations, with the more massive galaxies having higher SFR values but lower SSFR values than less massive galaxies. These results are consistent with previous ones showing that, at a given mass, high-redshift galaxies have on average larger SFR and SSFR values than low-redshift galaxies. Finally, bluer galaxies have larger SSFR values than redder

  14. The Dusty Galactic Center as Seen by SCUBA-2

    Science.gov (United States)

    Parsons, H.; Dempsey, J. T.; Thomas, H. S.; Berry, D.; Currie, M. J.; Friberg, P.; Wouterloot, J. G. A.; Chrysostomou, A.; Graves, S.; Tilanus, R. P. J.; Bell, G. S.; Rawlings, M. G.

    2018-02-01

    We present new JCMT SCUBA-2 observations of the Galactic Center region from 355^\\circ column density, mass, and concentration. No trends were seen in the data despite the recognition of three contributors to CO contamination: opacity, shocks, and temperature, which would be expected to relate to physical conditions. These SCUBA-2 Galactic Center data and catalog are available via https://doi.org/10.11570/17.0009.

  15. Astrophysics of gaseous nebulae and active galactic nuclei

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1989-01-01

    A graduate-level text and reference book on gaseous nebulae and the emission regions in Seyfert galaxies, quasars, and other types of active galactic nuclei (AGN) is presented. The topics discussed include: photoionization equilibrium, thermal equilibrium, calculation of emitted spectrum, comparison of theory with observations, internal dynamics of gaseous nebulae, interstellar dust, regions in the galactic context, planetary nebulae, nova and supernova remnants, diagnostics and physics of AGN, observational results on AGN

  16. GALACTIC AND EXTRAGALACTIC SUPERNOVA REMNANTS AS SITES OF PARTICLE ACCELERATION

    Directory of Open Access Journals (Sweden)

    Manami Sasaki

    2013-12-01

    Full Text Available Supernova remnants, owing to their strong shock waves, are likely sources of Galactic cosmic rays. Studies of supernova remnants in X-rays and gamma rays provide us with new insights into the acceleration of particles to high energies. This paper reviews the basic physics of supernova remnant shocks and associated particle acceleration and radiation processes. In addition, the study of supernova remnant populations in nearby galaxies and the implications for Galactic cosmic ray distribution are discussed.

  17. Broadband properties of active galactic nuclei

    Science.gov (United States)

    Edelson, Richard Allen

    The broadband radio-infrared-optical-ultraviolet properties of active galactic nuclei are used to investigate the nature of the central engine and the surrounding environment. Optically selected quasars and Seyfert 1 galaxies tend to have relatively flat infrared spectra and low reddenings, while most Seyfert 2 galaxies and other dusty objects have steep infrared spectra and larger reddenings. The infrared spectra of most luminous radio-quiet active galaxies turn over near approx. 80 micron. It appears that the infrared spectra of most quasars and luminous Seyfert 1 galaxies are dominated by unreprocessed radiation from a synchrotron self-absorbed source of order a light day across, about the size of the hypothesized accretion disk. Seyfert 2 galaxies and other reddened objects have infrared spectra which appear to be dominated by thermal emission from warm dust, probably in the disk of the underlying galaxy. A broad emission feature, centered near 5 micron, is present in many luminous quasars and Seyfert 1 galaxies. Highly polarized objects (blazars) can be strongly variable at far infrared wavelengths over time scales of months. Seyfert galaxies tend to have steep radio spectra.

  18. TESTING TESTS ON ACTIVE GALACTIC NUCLEI MICROVARIABILITY

    International Nuclear Information System (INIS)

    De Diego, Jose A.

    2010-01-01

    Literature on optical and infrared microvariability in active galactic nuclei (AGNs) reflects a diversity of statistical tests and strategies to detect tiny variations in the light curves of these sources. Comparison between the results obtained using different methodologies is difficult, and the pros and cons of each statistical method are often badly understood or even ignored. Even worse, improperly tested methodologies are becoming more and more common, and biased results may be misleading with regard to the origin of the AGN microvariability. This paper intends to point future research on AGN microvariability toward the use of powerful and well-tested statistical methodologies, providing a reference for choosing the best strategy to obtain unbiased results. Light curves monitoring has been simulated for quasars and for reference and comparison stars. Changes for the quasar light curves include both Gaussian fluctuations and linear variations. Simulated light curves have been analyzed using χ 2 tests, F tests for variances, one-way analyses of variance and C-statistics. Statistical Type I and Type II errors, which indicate the robustness and the power of the tests, have been obtained in each case. One-way analyses of variance and χ 2 prove to be powerful and robust estimators for microvariations, while the C-statistic is not a reliable methodology and its use should be avoided.

  19. Dissecting the large-scale galactic conformity

    Science.gov (United States)

    Seo, Seongu

    2018-01-01

    Galactic conformity is an observed phenomenon that galaxies located in the same region have similar properties such as star formation rate, color, gas fraction, and so on. The conformity was first observed among galaxies within in the same halos (“one-halo conformity”). The one-halo conformity can be readily explained by mutual interactions among galaxies within a halo. Recent observations however further witnessed a puzzling connection among galaxies with no direct interaction. In particular, galaxies located within a sphere of ~5 Mpc radius tend to show similarities, even though the galaxies do not share common halos with each other ("two-halo conformity" or “large-scale conformity”). Using a cosmological hydrodynamic simulation, Illustris, we investigate the physical origin of the two-halo conformity and put forward two scenarios. First, back-splash galaxies are likely responsible for the large-scale conformity. They have evolved into red galaxies due to ram-pressure stripping in a given galaxy cluster and happen to reside now within a ~5 Mpc sphere. Second, galaxies in strong tidal field induced by large-scale structure also seem to give rise to the large-scale conformity. The strong tides suppress star formation in the galaxies. We discuss the importance of the large-scale conformity in the context of galaxy evolution.

  20. ULTRAVIOLET EXTINCTION AT HIGH GALACTIC LATITUDES

    Energy Technology Data Exchange (ETDEWEB)

    Peek, J. E. G.; Schiminovich, David, E-mail: jegpeek@gmail.com [Department of Astronomy, Columbia University, New York, NY (United States)

    2013-07-01

    In order to study the properties and effects of high Galactic latitude dust, we present an analysis of 373,303 galaxies selected from the Galaxy Evolution Explorer All-Sky Survey and Wide-field Infrared Explorer All-Sky Data Release. By examining the variation in aggregate ultraviolet colors and number density of these galaxies, we measure the extinction curve at high latitude. We additionally consider a population of spectroscopically selected galaxies from the Sloan Digital Sky Survey to measure extinction in the optical. We find that dust at high latitude is neither quantitatively nor qualitatively consistent with standard reddening laws. Extinction in the FUV and NUV is {approx}10% and {approx}35% higher than expected, with significant variation across the sky. We find that no single R{sub V} parameter fits both the optical and ultraviolet extinction at high latitude, and that while both show detectable variation across the sky, these variations are not related. We propose that the overall trends we detect likely stem from an increase in very small silicate grains in the interstellar medium.

  1. ULTRAVIOLET EXTINCTION AT HIGH GALACTIC LATITUDES

    International Nuclear Information System (INIS)

    Peek, J. E. G.; Schiminovich, David

    2013-01-01

    In order to study the properties and effects of high Galactic latitude dust, we present an analysis of 373,303 galaxies selected from the Galaxy Evolution Explorer All-Sky Survey and Wide-field Infrared Explorer All-Sky Data Release. By examining the variation in aggregate ultraviolet colors and number density of these galaxies, we measure the extinction curve at high latitude. We additionally consider a population of spectroscopically selected galaxies from the Sloan Digital Sky Survey to measure extinction in the optical. We find that dust at high latitude is neither quantitatively nor qualitatively consistent with standard reddening laws. Extinction in the FUV and NUV is ∼10% and ∼35% higher than expected, with significant variation across the sky. We find that no single R V parameter fits both the optical and ultraviolet extinction at high latitude, and that while both show detectable variation across the sky, these variations are not related. We propose that the overall trends we detect likely stem from an increase in very small silicate grains in the interstellar medium.

  2. Detecting pulsars in the Galactic Centre

    Science.gov (United States)

    Rajwade, K. M.; Lorimer, D. R.; Anderson, L. D.

    2017-10-01

    Although high-sensitivity surveys have revealed a number of highly dispersed pulsars in the inner Galaxy, none have so far been found in the Galactic Centre (GC) region, which we define to be within a projected distance of 1 pc from Sgr A*. This null result is surprising given that several independent lines of evidence predict a sizable population of neutron stars in the region. Here, we present a detailed analysis of both the canonical and millisecond pulsar populations in the GC and consider free-free absorption and multipath scattering to be the two main sources of flux density mitigation. We demonstrate that the sensitivity limits of previous surveys are not sufficient to detect GC pulsar population, and investigate the optimum observing frequency for future surveys. Depending on the degree of scattering and free-free absorption in the GC, current surveys constrain the size of the potentially observable population (I.e. those beaming towards us) to be up to 52 canonical pulsars and 10 000 millisecond pulsars. We find that the optimum frequency for future surveys is in the range of 9-13 GHz. We also predict that future deeper surveys with the Square Kilometre array will probe a significant portion of the existing radio pulsar population in the GC.

  3. UBVJHK synthetic photometry of Galactic O stars

    Science.gov (United States)

    Martins, F.; Plez, B.

    2006-10-01

    Aims.The development of powerful infrared observational techniques enables the study of very extincted objects and young embedded star-forming regions. This is especially interesting in the context of massive stars that form and spend a non negligible fraction of their life still enshrouded in their parental molecular cloud. Spectrophotometric calibrations are thus necessary to constrain the physical properties of heavily extincted objects. Methods: Here, we derive UBVJHK magnitudes and bolometric corrections from a grid of atmosphere models for O stars. Bessel passbands are used. Bolometric corrections (BC) are derived as a function of Teff and are subsequently used to derive BC -spectral type (ST) and absolute magnitudes- ST relations. Results: Infrared magnitudes and, for the first time, bolometric corrections are given for the full range of spectral types and luminosity classes. Infrared colors are essentially constant, and (H-K)0 is 0.05 mag bluer than previously proposed. Optical calibrations are also provided and are similar to previous work, except for (B-V)0 which is found to be at minimum -0.28 for standard O stars, slightly higher (0.04 mag) than commonly accepted. Conclusions: We present a consistent set of photometric calibrations of optical and infrared magnitudes and bolometric corrections for Galactic O stars as a function of Teff and spectral type based on non-LTE atmosphere models including winds and line-blanketing.

  4. Dual Active Galactic Nuclei in Nearby Galaxies

    Science.gov (United States)

    Das, Mousumi; Rubinur, Khatun; Karb, Preeti; Varghese, Ashlin; Novakkuni, Navyasree; James, Atul

    2018-04-01

    Galaxy mergers play a crucial role in the formation of massive galaxies and the buildup of their bulges. An important aspect of the merging process is the in-spiral of the supermassive black-holes (SMBHs) to the centre of the merger remnant and the eventual formation of a SMBH binary. If both the SMBHs are accreting they will form a dual or binary active galactic nucleus (DAGN). The final merger remnant is usually very bright and shows enhanced star formation. In this paper we summarise the current sample of DAGN from previous studies and describe methods that can be used to identify strong DAGN candidates from optical and spectroscopic surveys. These methods depend on the Doppler separation of the double peaked AGN emission lines, the nuclear velocity dispersion of the galaxies and their optical/UV colours. We describe two high resolution, radio observations of DAGN candidates that have been selected based on their double peaked optical emission lines (DPAGN). We also examine whether DAGN host galaxies have higher star formation rates (SFRs) compared to merging galaxies that do not appear to have DAGN. We find that the SFR is not higher for DAGN host galaxies. This suggests that the SFRs in DAGN host galaxies is due to the merging process itself and not related to the presence of two AGN in the system.

  5. Unrecognized Astrometric Confusion in the Galactic Centre

    Science.gov (United States)

    Plewa, P. M.; Sari, R.

    2018-02-01

    The Galactic Centre is a highly crowded stellar field and frequent unrecognized events of source confusion, which involve undetected faint stars, are expected to introduce astrometric noise on a sub-mas level. This confusion noise is the main non-instrumental effect limiting the astrometric accuracy and precision of current near-infrared imaging observations and the long-term monitoring of individual stellar orbits in the vicinity of the central supermassive black hole. We self-consistently simulate the motions of the known and the yet unidentified stars to characterize this noise component and show that a likely consequence of source confusion is a bias in estimates of the stellar orbital elements, as well as the inferred mass and distance of the black hole, in particular if stars are being observed at small projected separations from it, such as the star S2 during pericentre passage. Furthermore, we investigate modeling the effect of source confusion as an additional noise component that is time-correlated, demonstrating a need for improved noise models to obtain trustworthy estimates of the parameters of interest (and their uncertainties) in future astrometric studies.

  6. Searching for dual active galactic nuclei

    Science.gov (United States)

    Rubinur, K.; Das, M.; Kharb, P.

    2018-02-01

    Binary or dual active galactic nuclei (DAGN) are expected from galaxy formation theories. However, confirmed DAGN are rare and finding these systems has proved to be challenging. Recent systematic searches for DAGN using double-peaked emission lines have yielded several new detections, as have the studies of samples of merging galaxies. In this paper, we present an updated list of DAGN compiled from published data. We also present preliminary results from our ongoing Expanded Very Large Array (EVLA) radio study of eight double-peaked emission-line AGN (DPAGN). One of the sample galaxy shows an S-shaped radio jet. Using new and archival data, we have successfully fitted a precessing jet model to this radio source. We find that the jet precession could be due to a binary AGN with a super-massive black-hole (SMBH) separation of ˜ 0.02 pc or a single AGN with a tilted accretion disk. We have found that another sample galaxy, which is undergoing a merger, has two radio cores with a projected separation of 5.6 kpc. We discuss the preliminary results from our radio study.

  7. Virgin galactic the first ten years

    CERN Document Server

    Seedhouse, Erik

    2015-01-01

    Thirty years ago when Sir Richard Branson called up Boeing and asked if they had a spare 747, few would have predicted the brash entrepreneur would so radically transform the placid business of air travel. But today, Branson flies airlines on six continents, employs hundreds of jets and, in 2014, was predicting that his spaceship company – Virgin Galactic – would soon open the space frontier to commercial astronauts, payload specialists, scientists and space tourists. With more than 600 seats sold at $250,000 each, what started off as a dream to send people just for the excitement to look back and marvel at Earth, was on the cusp of finally being turned into a business. Then, on October 21, 2014, tragedy struck. SpaceShipTwo was on its most ambitious test flight to date. Seconds after firing its engine, Virgin Galactic’s spaceship was breaking through the sound barrier. In just the three seconds that it took for the vehicle to climb from Mach 0.94 to Mach 1.02, co-pilot Mike Alsbury made what many close...

  8. Catchment legacies and time lags: a parsimonious watershed model to predict the effects of legacy storage on nitrogen export.

    Directory of Open Access Journals (Sweden)

    Kimberly J Van Meter

    Full Text Available Nutrient legacies in anthropogenic landscapes, accumulated over decades of fertilizer application, lead to time lags between implementation of conservation measures and improvements in water quality. Quantification of such time lags has remained difficult, however, due to an incomplete understanding of controls on nutrient depletion trajectories after changes in land-use or management practices. In this study, we have developed a parsimonious watershed model for quantifying catchment-scale time lags based on both soil nutrient accumulations (biogeochemical legacy and groundwater travel time distributions (hydrologic legacy. The model accurately predicted the time lags observed in an Iowa watershed that had undergone a 41% conversion of area from row crop to native prairie. We explored the time scales of change for stream nutrient concentrations as a function of both natural and anthropogenic controls, from topography to spatial patterns of land-use change. Our results demonstrate that the existence of biogeochemical nutrient legacies increases time lags beyond those due to hydrologic legacy alone. In addition, we show that the maximum concentration reduction benefits vary according to the spatial pattern of intervention, with preferential conversion of land parcels having the shortest catchment-scale travel times providing proportionally greater concentration reductions as well as faster response times. In contrast, a random pattern of conversion results in a 1:1 relationship between percent land conversion and percent concentration reduction, irrespective of denitrification rates within the landscape. Our modeling framework allows for the quantification of tradeoffs between costs associated with implementation of conservation measures and the time needed to see the desired concentration reductions, making it of great value to decision makers regarding optimal implementation of watershed conservation measures.

  9. How to restore the fiduciary relationship. An interview with Eliot Spitzer. Interview by Louise O'Brien.

    Science.gov (United States)

    Spitzer, Eliot

    2004-05-01

    Eliot Spitzer's investigations into the mutual fund and investment-banking industries have made the New York State attorney general the de facto flag bearer of corporate reform. His exposure of conflicts of interest between investment bankers and research analyst in Wall Street firms led to the $1.4 billion global settlement between regulators and banking houses in 2003. In this interview, Spitzer describes the challenge of protecting public markets from conflicts of interest, paying particular attention to how such conflicts get institutionalized in an industry. "The cases that have gotten me and my fellow regulators most upset are the ones where we've seen senior management being tolerant of rank abuses," he says. "Because then you know that the entire structure is rotten." He also points the finger squarely at boards, maintaining that board members are drawn from pools of company and industry insiders. He cites "a void in values in a lot of boardrooms," holding up executive compensation as a powerful example. "Board compensation committees ... are self-selected and interwoven--it's a rigged marketplace." He continues, "It would be interesting to see what the world would look like if CEO pay packages had to be submitted to shareholder votes." Spitzer suggests that what's really needed is for all business leaders to reinstill throughout their organizations the critical notion of a fiduciary duty--whether it is to the shareholder or to the customer. Using the mutual fund industry as an example, he also contrasts the value of enforcement with that of regulation and articulates an important--and surprisingly limited--role for government in protecting free markets.

  10. The Demographics and Properties of Wide-Orbit, Planetary-Mass Companions from PSF Fitting of Spitzer/IRAC Images

    Science.gov (United States)

    Martinez, Raquel; Kraus, Adam L.

    2017-06-01

    Over the past decade, a growing population of planetary-mass companions ( 100 AU) from their host stars, challenging existing models of both star and planet formation. It is unclear whether these systems represent the low-mass extreme of stellar binary formation or the high-mass and wide-orbit extreme of planet formation theories, as various proposed formation pathways inadequately explain the physical and orbital aspects of these systems. Even so, determining which scenario best reproduces the observed characteristics of the PMCs will come once a statistically robust sample of directly-imaged PMCs are found and studied.We are developing an automated pipeline to search for wide-orbit PMCs to young stars in Spitzer/IRAC images. A Markov Chain Monte Carlo (MCMC) algorithm is the backbone of our novel point spread function (PSF) subtraction routine that efficiently creates and subtracts χ2-minimizing instrumental PSFs, simultaneously measuring astrometry and infrared photometry of these systems across the four IRAC channels (3.6 μm, 4.5 μm, 5.8 μm, and 8 μm). In this work, we present the results of a Spitzer/IRAC archival imaging study of 11 young, low-mass (0.044-0.88 M⊙ K3.5-M7.5) stars known to have faint, low-mass companions in 3 nearby star-forming regions (Chameleon, Taurus, and Upper Scorpius). We characterize the systems found to have low-mass companions with non-zero [I1] - [I4] colors, potentially signifying the presence of a circum(sub?)stellar disk. Plans for future pipeline improvements and paths forward will also be discussed. Once this computational foundation is optimized, the stage is set to quickly scour the nearby star-forming regions already imaged by Spitzer, identify potential candidates for further characterization with ground- or space-based telescopes, and increase the number of widely-separated PMCs known.

  11. Spitzer Observations of Comet 9P/Tempel 1 During Deep Impact : Water and Dust Production and Spatial Distribution

    Science.gov (United States)

    Gicquel, Adeline; Bockelée-Morvan, D.; Kelley, M. S.; Woodward, C. E.

    2009-09-01

    The Deep Impact (DI) spacecraft encountered comet 9P/Tempel 1 on July 4th, 2005 (rh = 1.506 AU). Spectral maps covering 20'' x 67'' (1.85''/pixel) were acquired with the IRS instrument on the Spitzer Space Telescope (ΔSpitzer = 0.72 AU) at different times around the Deep Impact event: twice before impact (TI-41.3hrs and TI-22.9hrs) and twelve times after impact (between TI+0.67hrs and TI+1027hrs). These IRS observations (Lisse et al 2006, Sciences 313, 635) were taken from the Spitzer data archive. We present the interpretation of 5.2-7.6 µm spectra obtained in the second order of the short-wavelength module (SL2). To reduce the contribution of artifacts in the spectra, 5x5 pixel extraction apertures (9.25''x9.25'') were used. On the first stage we studied the water ν2 vibrational band emission at 6.4µm, which is present in most spectra. The water production rate before impact is deduced ( 4.25e27 molecules/sec). In order to study both the amount and origin of the water molecules released after impact, we used extractions centered on the nucleus and along the length of the slit. We analyzed the spatial distribution of water and its time evolution with a time-dependent model which describes the evolution of the water cloud after impact. The underlying continuum in the spectra provides information on the evolution and color temperature of the dust ejecta. The dust mass and dust/gas ratio in the ejecta cloud are derived and compared with other values published in the literature.

  12. The Spitzer search for the transits of HARPS low-mass planets. II. Null results for 19 planets

    Science.gov (United States)

    Gillon, M.; Demory, B.-O.; Lovis, C.; Deming, D.; Ehrenreich, D.; Lo Curto, G.; Mayor, M.; Pepe, F.; Queloz, D.; Seager, S.; Ségransan, D.; Udry, S.

    2017-05-01

    Short-period super-Earths and Neptunes are now known to be very frequent around solar-type stars. Improving our understanding of these mysterious planets requires the detection of a significant sample of objects suitable for detailed characterization. Searching for the transits of the low-mass planets detected by Doppler surveys is a straightforward way to achieve this goal. Indeed, Doppler surveys target the most nearby main-sequence stars, they regularly detect close-in low-mass planets with significant transit probability, and their radial velocity data constrain strongly the ephemeris of possible transits. In this context, we initiated in 2010 an ambitious Spitzer multi-Cycle transit search project that targeted 25 low-mass planets detected by radial velocity, focusing mainly on the shortest-period planets detected by the HARPS spectrograph. We report here null results for 19 targets of the project. For 16 planets out of 19, a transiting configuration is strongly disfavored or firmly rejected by our data for most planetary compositions. We derive a posterior probability of 83% that none of the probed 19 planets transits (for a prior probability of 22%), which still leaves a significant probability of 17% that at least one of them does transit. Globally, our Spitzer project revealed or confirmed transits for three of its 25 targeted planets, and discarded or disfavored the transiting nature of 20 of them. Our light curves demonstrate for Warm Spitzer excellent photometric precisions: for 14 targets out of 19, we were able to reach standard deviations that were better than 50 ppm per 30 min intervals. Combined with its Earth-trailing orbit, which makes it capable of pointing any star in the sky and to monitor it continuously for days, this work confirms Spitzer as an optimal instrument to detect sub-mmag-deep transits on the bright nearby stars targeted by Doppler surveys. The photometric and radial velocity time series used in this work are only available at the

  13. The Spitzer survey of interstellar clouds in the Gould Belt. III. A multi-wavelength view of Corona Australis

    DEFF Research Database (Denmark)

    Peterson, Dawn E.; Caratti o Garatti, Alessio; Bourke, Tyler L.

    2011-01-01

    retrieved from the literature are also added to the list, and a total of 116 candidate YSOs in CrA are compiled. Based on these YSO candidates, the star formation rate is computed to be 12 M sun Myr-1, similar to that of the Lupus clouds. A clustering analysis was also performed, finding that the main....... Using the Spitzer data, we identify 51 young stellar objects (YSOs) in CrA which include sources in the well-studied Coronet cluster as well as sources distributed throughout the molecular cloud. Twelve of the YSOs discussed are new candidates, one of which is located in the Coronet. Known YSOs...

  14. LOW FALSE POSITIVE RATE OF KEPLER CANDIDATES ESTIMATED FROM A COMBINATION OF SPITZER AND FOLLOW-UP OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Désert, Jean-Michel; Brown, Timothy M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Charbonneau, David; Torres, Guillermo; Fressin, François; Ballard, Sarah; Latham, David W. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bryson, Stephen T.; Borucki, William J. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Batalha, Natalie M. [San Jose State University, San Jose, CA 95192 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Ford, Eric B. [University of Florida, Gainesville, FL 32611 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Gilliland, Ronald L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Seager, Sara, E-mail: desert@colorado.edu [Massachusetts Institute of Technology, Cambridge, MA 02159 (United States)

    2015-05-01

    NASA’s Kepler mission has provided several thousand transiting planet candidates during the 4 yr of its nominal mission, yet only a small subset of these candidates have been confirmed as true planets. Therefore, the most fundamental question about these candidates is the fraction of bona fide planets. Estimating the rate of false positives of the overall Kepler sample is necessary to derive the planet occurrence rate. We present the results from two large observational campaigns that were conducted with the Spitzer Space Telescope during the the Kepler mission. These observations are dedicated to estimating the false positive rate (FPR) among the Kepler candidates. We select a sub-sample of 51 candidates, spanning wide ranges in stellar, orbital, and planetary parameter space, and we observe their transits with Spitzer at 4.5 μm. We use these observations to measures the candidate’s transit depths and infrared magnitudes. An authentic planet produces an achromatic transit depth (neglecting the modest effect of limb darkening). Conversely a bandpass-dependent depth alerts us to the potential presence of a blending star that could be the source of the observed eclipse: a false positive scenario. For most of the candidates (85%), the transit depths measured with Kepler are consistent with the transit depths measured with Spitzer as expected for planetary objects, while we find that the most discrepant measurements are due to the presence of unresolved stars that dilute the photometry. The Spitzer constraints on their own yield FPRs between 5% and depending on the Kepler Objects of Interest. By considering the population of the Kepler field stars, and by combining follow-up observations (imaging) when available, we find that the overall FPR of our sample is low. The measured upper limit on the FPR of our sample is 8.8% at a confidence level of 3σ. This observational result, which uses the achromatic property of planetary transit signals that is not investigated

  15. THE LAST GASP OF GAS GIANT PLANET FORMATION: A SPITZER STUDY OF THE 5 Myr OLD CLUSTER NGC 2362

    International Nuclear Information System (INIS)

    Currie, Thayne; Lada, Charles J.; Robitaille, Thomas P.; Irwin, Jonathan; Kenyon, Scott J.; Plavchan, Peter

    2009-01-01

    Expanding upon the Infrared Array Camera (IRAC) survey from Dahm and Hillenbrand, we describe Spitzer IRAC and Multiband Imaging Photometer for Spitzer observations of the populous, 5 Myr old open cluster NGC 2362. We analyze the mid-IR colors of cluster members and compared their spectral energy distributions (SEDs) to star+circumstellar disk models to constrain the disk morphologies and evolutionary states. Early/intermediate-type confirmed/candidate cluster members either have photospheric mid-IR emission or weak, optically thin IR excess emission at λ ≥ 24 μm consistent with debris disks. Few late-type, solar/subsolar-mass stars have primordial disks. The disk population around late-type stars is dominated by disks with inner holes (canonical 'transition disks') and 'homologously depleted' disks. Both types of disks represent an intermediate stage between primordial disks and debris disks. Thus, in agreement with previous results, we find that multiple paths for the primordial-to-debris disk transition exist. Because these 'evolved primordial disks' greatly outnumber primordial disks, our results undermine standard arguments in favor of a ∼ 5 yr timescale for the transition based on data from Taurus-Auriga. Because the typical transition timescale is far longer than 10 5 yr, these data also appear to rule out standard ultraviolet photoevaporation scenarios as the primary mechanism to explain the transition. Combining our data with other Spitzer surveys, we investigate the evolution of debris disks around high/intermediate-mass stars and investigate timescales for giant planet formation. Consistent with Currie et al., the luminosity of 24 μm emission in debris disks due to planet formation peaks at ∼10-20 Myr. If the gas and dust in disks evolve on similar timescales, the formation timescale for gas giant planets surrounding early-type, high/intermediate-mass (∼>1.4 M sun ) stars is likely 1-5 Myr. Most solar/subsolar-mass stars detected by Spitzer

  16. The Near-infrared Optimal Distances Method Applied to Galactic Classical Cepheids Tightly Constrains Mid-infrared Period–Luminosity Relations

    Science.gov (United States)

    Wang, Shu; Chen, Xiaodian; de Grijs, Richard; Deng, Licai

    2018-01-01

    Classical Cepheids are well-known and widely used distance indicators. As distance and extinction are usually degenerate, it is important to develop suitable methods to robustly anchor the distance scale. Here, we introduce a near-infrared optimal distance method to determine both the extinction values of and distances to a large sample of 288 Galactic classical Cepheids. The overall uncertainty in the derived distances is less than 4.9%. We compare our newly determined distances to the Cepheids in our sample with previously published distances to the same Cepheids with Hubble Space Telescope parallax measurements and distances based on the IR surface brightness method, Wesenheit functions, and the main-sequence fitting method. The systematic deviations in the distances determined here with respect to those of previous publications is less than 1%–2%. Hence, we constructed Galactic mid-IR period–luminosity (PL) relations for classical Cepheids in the four Wide-Field Infrared Survey Explorer (WISE) bands (W1, W2, W3, and W4) and the four Spitzer Space Telescope bands ([3.6], [4.5], [5.8], and [8.0]). Based on our sample of hundreds of Cepheids, the WISE PL relations have been determined for the first time; their dispersion is approximately 0.10 mag. Using the currently most complete sample, our Spitzer PL relations represent a significant improvement in accuracy, especially in the [3.6] band which has the smallest dispersion (0.066 mag). In addition, the average mid-IR extinction curve for Cepheids has been obtained: {A}W1/{A}{K{{s}}}≈ 0.560, {A}W2/{A}{K{{s}}}≈ 0.479, {A}W3/{A}{K{{s}}}≈ 0.507, {A}W4/{A}{K{{s}}}≈ 0.406, {A}[3.6]/{A}{K{{s}}}≈ 0.481, {A}[4.5]/{A}{K{{s}}}≈ 0.469, {A}[5.8]/{A}{K{{s}}}≈ 0.427, and {A}[8.0]/{A}{K{{s}}}≈ 0.427 {mag}.

  17. Legacy model integration for enhancing hydrologic interdisciplinary research

    Science.gov (United States)

    Dozier, A.; Arabi, M.; David, O.

    2013-12-01

    Many challenges are introduced to interdisciplinary research in and around the hydrologic science community due to advances in computing technology and modeling capabilities in different programming languages, across different platforms and frameworks by researchers in a variety of fields with a variety of experience in computer programming. Many new hydrologic models as well as optimization, parameter estimation, and uncertainty characterization techniques are developed in scripting languages such as Matlab, R, Python, or in newer languages such as Java and the .Net languages, whereas many legacy models have been written in FORTRAN and C, which complicates inter-model communication for two-way feedbacks. However, most hydrologic researchers and industry personnel have little knowledge of the computing technologies that are available to address the model integration process. Therefore, the goal of this study is to address these new challenges by utilizing a novel approach based on a publish-subscribe-type system to enhance modeling capabilities of legacy socio-economic, hydrologic, and ecologic software. Enhancements include massive parallelization of executions and access to legacy model variables at any point during the simulation process by another program without having to compile all the models together into an inseparable 'super-model'. Thus, this study provides two-way feedback mechanisms between multiple different process models that can be written in various programming languages and can run on different machines and operating systems. Additionally, a level of abstraction is given to the model integration process that allows researchers and other technical personnel to perform more detailed and interactive modeling, visualization, optimization, calibration, and uncertainty analysis without requiring deep understanding of inter-process communication. To be compatible, a program must be written in a programming language with bindings to a common

  18. (Resurveying Mediterranean Rural Landscapes: GIS and Legacy Survey Data

    Directory of Open Access Journals (Sweden)

    Robert Witcher

    2008-07-01

    Full Text Available Legacy data have always been important for Mediterranean archaeologists. Over the past decade, one specific category of legacy data, that deriving from regional survey, has become particularly important. Not only has the scale of research questions become larger (requiring greater reliance on others' data, but the surface archaeological record is deteriorating (diminishing the ability to recover good data. The legacy data from many individual surveys have now been subject to digitisation and GIS analysis, successfully redeploying data collected for one purpose within new theoretical and interpretive frameworks. However, a key research focus is now comparative survey - using the results of many different Mediterranean surveys side-by-side to identify regional variability in settlement organisation, economy and demography. In order to overcome the significant methodological differences between these surveys, attention has focused on the documentation of metadata. Yet, many legacy data lack vital information about their creation and hence how they might be (reinterpreted and compared. GIS has been advanced as an environment in which to contain, order and analyse the data necessary for comparative survey. However, there is a danger that the technology will facilitate inappropriate use of these datasets in a way that fails to acknowledge and understand the very real differences between them. Here, emphasis is placed upon the use of GIS as a space for exploratory data analysis: a process that encompasses and emphasises the integral processes of digitisation, visualisation and simple analysis for the characterisation of datasets in order to derive an alternative form of metadata. Particular emphasis is placed upon the interaction of past human behaviour (e.g. in the Roman period and archaeological recovery (i.e. the behaviour of archaeologists in the present, or recent past; these two sets of 'social action' combine to create distinctive archaeological

  19. Two tales of legacy effects on stream nutrient behaviour

    Science.gov (United States)

    Bieroza, M.; Heathwaite, A. L.

    2017-12-01

    Intensive agriculture has led to large-scale land use conversion, shortening of flow pathways and increased loads of nutrients in streams. This legacy results in gradual build-up of nutrients in agricultural catchments: in soil for phosphorus (biogeochemical legacy) and in the unsaturated zone for nitrate (hydrologic legacy), controlling the water quality in the long-term. Here we investigate these effects on phosphorus and nitrate stream concentrations using high-frequency (10-5 - 100 Hz) sampling with in situ wet-chemistry analysers and optical sensors. Based on our 5 year study, we observe that storm flow responses differ for both nutrients: phosphorus shows rapid increases (up to 3 orders of magnitude) in concentrations with stream flow, whereas nitrate shows both dilution and concentration effects with increasing flow. However, the range of nitrate concentrations change is narrow (up to 2 times the mean) and reflects chemostatic behaviour. We link these nutrient responses with their dominant sources and flow pathways in the catchment. Nitrate from agriculture (with the peak loading in 1983) is stored in the unsaturated zone of the Penrith Sandstone, which can reach up to 70 m depth. Thus nitrate legacy is related to a hydrologic time lag with long travel times in the unsaturated zone. Phosphorus is mainly sorbed to soil particles, therefore it is mobilised rapidly during rainfall events (biogeochemical legacy). The phosphorus stream response will however depend on how well connected is the stream to the catchment sources (driven by soil moisture distribution) and biogeochemical activity (driven by temperature), leading to both chemostatic and non-chemostatic responses, alternating on a storm-to-storm and seasonal basis. Our results also show that transient within-channel storage is playing an important role in delivery of phosphorus, providing an additional time lag component. These results show, that consistent agricultural legacy in the catchment (high

  20. The galactic disk surface mass density and the Galactic force K(z) at z = 1.1 kiloparsecs

    International Nuclear Information System (INIS)

    Kuijken, K.; Gilmore, G.

    1991-01-01

    A set of distance and velocity data previously obtained and analyzed is rediscussed to determine the surface mass density of the Galactic disk. These data reliably determine the integral surface mass density of all (disk + halo) Galactic components within 1.1 kpc from the Galactic plane near the sun to be 71 + or 6 solar masses/sq pc, independent of the disk/halo ratio. Determination of the fraction of this total mass which is distributed in the Galactic disk and the fraction which is associated with an extended halo remains highly model-dependent. The best available estimate of the relative contributions of disk mass and halo mass to the local integral surface density, obtained from modeling of the Galactic rotation curve, yields a surface mass density of 48 + or - 9 solar masses/sq pc for mass associated with the Galactic disk near the sun. The corresponding mass of identified disk matter is 48 + or - 8 solar masses/sq pc. 7 refs

  1. Galactic Data Viewer, Version 2.08 (by Galactic Industries Corporation)

    Science.gov (United States)

    Goldsmith, Jack G.

    1998-09-01

    Salem, NH, 1997. Free via download from www.galactic.com. The modern practice of chemistry depends heavily upon instrumentation and the interpretation of the data it provides. At a time when chemical instrumentation is increasing in power, complexity, and cost, the instrumentation budgets of most institutions do not provide the resources necessary to take advantage of any new and improved capability. The result is that discussion of instrumentation not already on hand becomes more an exercise in the abstract and less a chance for students to get direct experience with the data these other methods and techniques provide. Confining lectures, dry-labs, and homework assignments to spectra or chromatograms photocopied from textbooks and journal articles will go only so far when trying to convey a sense of what can be gained from other instrumental methods and what it is to have access to "real" data. Even when instrumentation is available, time constraints may prevent access or utilization for educationally meaningful applications, leaving students in a position to simply accept generalizations as true. A freeware product from Galactic Industries Corp. (Salem, NH), however, provides a means to share actual data from a wide variety of instruments among interested parties, increase student involvement with data, and help overcome the limitations mentioned earlier.

  2. SPARC: MASS MODELS FOR 175 DISK GALAXIES WITH SPITZER PHOTOMETRY AND ACCURATE ROTATION CURVES

    Energy Technology Data Exchange (ETDEWEB)

    Lelli, Federico; McGaugh, Stacy S. [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106 (United States); Schombert, James M., E-mail: federico.lelli@case.edu [Department of Physics, University of Oregon, Eugene, OR 97403 (United States)

    2016-12-01

    We introduce SPARC ( Spitzer Photometry and Accurate Rotation Curves): a sample of 175 nearby galaxies with new surface photometry at 3.6  μ m and high-quality rotation curves from previous H i/H α studies. SPARC spans a broad range of morphologies (S0 to Irr), luminosities (∼5 dex), and surface brightnesses (∼4 dex). We derive [3.6] surface photometry and study structural relations of stellar and gas disks. We find that both the stellar mass–H i mass relation and the stellar radius–H i radius relation have significant intrinsic scatter, while the H i   mass–radius relation is extremely tight. We build detailed mass models and quantify the ratio of baryonic to observed velocity ( V {sub bar}/ V {sub obs}) for different characteristic radii and values of the stellar mass-to-light ratio (ϒ{sub ⋆}) at [3.6]. Assuming ϒ{sub ⋆} ≃ 0.5 M {sub ⊙}/ L {sub ⊙} (as suggested by stellar population models), we find that (i) the gas fraction linearly correlates with total luminosity; (ii) the transition from star-dominated to gas-dominated galaxies roughly corresponds to the transition from spiral galaxies to dwarf irregulars, in line with density wave theory; and (iii)  V {sub bar}/ V {sub obs} varies with luminosity and surface brightness: high-mass, high-surface-brightness galaxies are nearly maximal, while low-mass, low-surface-brightness galaxies are submaximal. These basic properties are lost for low values of ϒ{sub ⋆} ≃ 0.2 M {sub ⊙}/ L {sub ⊙} as suggested by the DiskMass survey. The mean maximum-disk limit in bright galaxies is ϒ{sub ⋆} ≃ 0.7 M {sub ⊙}/ L {sub ⊙} at [3.6]. The SPARC data are publicly available and represent an ideal test bed for models of galaxy formation.

  3. COSMIC INFRARED BACKGROUND FLUCTUATIONS IN DEEP SPITZER INFRARED ARRAY CAMERA IMAGES: DATA PROCESSING AND ANALYSIS

    International Nuclear Information System (INIS)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

    2010-01-01

    This paper provides a detailed description of the data reduction and analysis procedures that have been employed in our previous studies of spatial fluctuation of the cosmic infrared background (CIB) using deep Spitzer Infrared Array Camera observations. The self-calibration we apply removes a strong instrumental signal from the fluctuations that would otherwise corrupt the results. The procedures and results for masking bright sources and modeling faint sources down to levels set by the instrumental noise are presented. Various tests are performed to demonstrate that the resulting power spectra of these fields are not dominated by instrumental or procedural effects. These tests indicate that the large-scale (∼>30') fluctuations that remain in the deepest fields are not directly related to the galaxies that are bright enough to be individually detected. We provide the parameterization of these power spectra in terms of separate instrument noise, shot noise, and power-law components. We discuss the relationship between fluctuations measured at different wavelengths and depths, and the relations between constraints on the mean intensity of the CIB and its fluctuation spectrum. Consistent with growing evidence that the ∼1-5 μm mean intensity of the CIB may not be as far above the integrated emission of resolved galaxies as has been reported in some analyses of DIRBE and IRTS observations, our measurements of spatial fluctuations of the CIB intensity indicate the mean emission from the objects producing the fluctuations is quite low (∼>1 nW m -2 sr -1 at 3-5 μm), and thus consistent with current γ-ray absorption constraints. The source of the fluctuations may be high-z Population III objects, or a more local component of very low luminosity objects with clustering properties that differ from the resolved galaxies. Finally, we discuss the prospects of the upcoming space-based surveys to directly measure the epochs inhabited by the populations producing these

  4. INFRARED SPECTROSCOPY OF COMET 73P/SCHWASSMANN-WACHMANN 3 USING THE SPITZER SPACE TELESCOPE

    International Nuclear Information System (INIS)

    Sitko, Michael L.; Whitney, Barbara A.; Wolff, Michael J.; Lisse, Carey M.; Kelley, Michael S.; Polomski, Elisha F.; Lynch, David K.; Russell, Ray W.; Kimes, Robin L.; Harker, David E.

    2011-01-01

    We have used the Spitzer Space Telescope Infrared Spectrograph (IRS) to observe the 5-37 μm thermal emission of comet 73P/Schwassmann-Wachmann 3 (SW3), components B and C. We obtained low spectral resolution (R ∼ 100) data over the entire wavelength interval, along with images at 16 and 22 μm. These observations provided an unprecedented opportunity to study nearly pristine material from the surface and what was until recently the interior of an ecliptic comet-the cometary surface having experienced only two prior perihelion passages, and including material that was totally fresh. The spectra were modeled using a variety of mineral types including both amorphous and crystalline components. We find that the degree of silicate crystallinity, ∼35%, is somewhat lower than most other comets with strong emission features, while its abundance of amorphous carbon is higher. Both suggest that SW3 is among the most chemically primitive solar system objects yet studied in detail, and that it formed earlier or farther from the Sun than the bulk of the comets studied so far. The similar dust compositions of the two fragments suggest that these are not mineralogically heterogeneous, but rather uniform throughout their volumes. The best-fit particle size distribution for SW3B has a form dn/da ∼ a -3.5 , close to that expected for dust in collisional equilibrium, while that for SW3C has dn/da ∼ a -4.0 , as seen mostly in active comets with strong directed jets, such as C/1995 O1 Hale-Bopp. The total mass of dust in the comae plus nearby tail, extrapolated from the field of view of the IRS peak-up image arrays, is (3-5) x 10 8 kg for B and (7-9) x 10 8 kg for C. Atomic abundances derived from the spectral models indicate a depletion of O compared to solar photospheric values, despite the inclusion of water ice and gas in the models. Atomic C may be solar or slightly sub-solar, but its abundance is complicated by the potential contribution of spectrally featureless mineral

  5. SPITZER SPECTROSCOPY OF CIRCUMSTELLAR DISKS IN THE 5 Myr OLD UPPER SCORPIUS OB ASSOCIATION

    International Nuclear Information System (INIS)

    Dahm, S. E.; Carpenter, John M.

    2009-01-01

    We present mid-infrared spectra between 5.2 and 38 μm for 26 disk-bearing members of the ∼5 Myr old Upper Scorpius OB association obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. We find clear evidence for changes in the spectral characteristics of dust emission between the early-type (B+A) and late-type (K+M) infrared excess stars. The early-type members exhibit featureless continuum excesses that become apparent redward of ∼8 μm. In contrast, 10 and 20 μm silicate features or polycyclic aromatic hydrocarbon emission are present in all but one of the late-type excess members of Upper Scorpius. The strength of silicate emission among late-type Upper Scorpius members is spectral-type dependent, with the most prominent features being associated with K5-M2-type stars. By fitting the spectral energy distributions (SED) of a representative sample of low-mass stars with accretion disk models, we find that the SEDs are consistent with models having inner disk radii ranging from ∼0.2 to 1.2 AU. Complementary high-resolution (R ∼ 33, 000) optical (λλ4800-9200) spectra for the Upper Scorpius excess stars were examined for signatures of gaseous accretion. Of the 35 infrared excess stars identified in Upper Scorpius, only seven (all late-type) exhibit definitive signatures of accretion. Mass-accretion rates for these stars were estimated to range from 10 -11 to 10 -8.9 M sun yr -1 . Compared to Class II sources in Taurus-Auriga, the disk population in Upper Scorpius exhibits reduced levels of near- and mid-infrared excess emission and an order of magnitude lower mass-accretion rates. These results suggest that the disk structure has changed significantly over the 2-4 Myr in age separating these two stellar populations. The ubiquity of depleted inner disks in the Upper Scorpius excess sample implies that such disks are a common evolutionary pathway that persists for some time.

  6. Electron Energy Distribution in Hotspots of Cygnus A:Filling the Gap with Spitzer Space Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Stawarz, L.; Cheung, C.C.; Harris, D.E.; Ostrowski, M.

    2007-03-06

    Here we present Spitzer Space Telescope imaging of Cyg A with the Infrared Array Camera at 4.5 {micro}m and 8.0 {micro}m, resulting in the detection of the high-energy tails or cut-offs in the synchrotron spectra for all four hotspots of this archetype radio galaxy. When combined with the other data collected (and re-analyzed) from the literature, our observations allow for detailed modeling of the broad-band (radio-to-X-ray) emission for the brightest spots A and D. We confirm that the X-ray flux detected previously from these features is consistent with the synchrotron self-Compton radiation for the magnetic field intensity B {approx} 170 {micro}G in spot A, and B {approx} 270 {micro}G in spot D. We also find that the energy density of the emitting electrons is most likely larger by a factor of a few than the energy density of the hotspots magnetic field. We construct energy spectra of the radiating ultrarelativistic electrons. We find that for both hotspots A and D these spectra are consistent with a broken power-law extending from at least 100MeV up to {approx} 100GeV, and that the spectral break corresponds almost exactly to the proton rest energy of {approx} 1GeV. We argue that the shape of the electron continuum most likely reflects two different regimes of the electron acceleration process taking place at mildly relativistic shocks, rather than resulting from radiative cooling and/or absorption e.ects. In this picture the protons inertia defines the critical energy for the hotspot electrons above which Fermi-type acceleration processes may play a major role, but below which the operating acceleration mechanism has to be of a different type. At energies {approx}> 100 GeV, the electron spectra cut-off/steepen again, most likely as a result of spectral aging due to radiative loss effects. We discuss several implications of the presented analysis for the physics of extragalactic jets.

  7. Electron Energy Distribution in Hotspots of Cygnus A:Filling the Gap with Spitzer Space Telescope

    International Nuclear Information System (INIS)

    Stawarz, L.; Cheung, C.C.; Harris, D.E.; Ostrowski, M.

    2007-01-01

    Here we present Spitzer Space Telescope imaging of Cyg A with the Infrared Array Camera at 4.5 (micro)m and 8.0 (micro)m, resulting in the detection of the high-energy tails or cut-offs in the synchrotron spectra for all four hotspots of this archetype radio galaxy. When combined with the other data collected (and re-analyzed) from the literature, our observations allow for detailed modeling of the broad-band (radio-to-X-ray) emission for the brightest spots A and D. We confirm that the X-ray flux detected previously from these features is consistent with the synchrotron self-Compton radiation for the magnetic field intensity B ∼ 170 (micro)G in spot A, and B ∼ 270 (micro)G in spot D. We also find that the energy density of the emitting electrons is most likely larger by a factor of a few than the energy density of the hotspots magnetic field. We construct energy spectra of the radiating ultrarelativistic electrons. We find that for both hotspots A and D these spectra are consistent with a broken power-law extending from at least 100MeV up to ∼ 100GeV, and that the spectral break corresponds almost exactly to the proton rest energy of ∼ 1GeV. We argue that the shape of the electron continuum most likely reflects two different regimes of the electron acceleration process taking place at mildly relativistic shocks, rather than resulting from radiative cooling and/or absorption e.ects. In this picture the protons inertia defines the critical energy for the hotspot electrons above which Fermi-type acceleration processes may play a major role, but below which the operating acceleration mechanism has to be of a different type. At energies ∼> 100 GeV, the electron spectra cut-off/steepen again, most likely as a result of spectral aging due to radiative loss effects. We discuss several implications of the presented analysis for the physics of extragalactic jets

  8. Physical Characterization of Warm Spitzer-observed Near-Earth Objects

    Science.gov (United States)

    Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delbo, Marco; Hora, Joseph L.; Mueller, Michael

    2014-01-01

    Near-infrared spectroscopy of Near-Earth Objects (NEOs) connects diagnostic spectral features to specific surface mineralogies. The combination of spectroscopy with albedos and diameters derived from thermal infrared observations can increase the scientific return beyond that of the individual datasets. For instance, some taxonomic classes can be separated into distinct compositional groupings with albedo and different mineralogies with similar albedos can be distinguished with spectroscopy. To that end, we have completed a spectroscopic observing campaign to complement the ExploreNEOs Warm Spitzer program that obtained albedos and diameters of nearly 600 NEOs (Trilling et al., 2010). The spectroscopy campaign included visible and near-infrared observations of ExploreNEOs targets from various observatories. Here we present the results of observations using the low-resolution prism mode (approx. 0.7-2.5 microns) of the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). We also include near-infrared observations of Explore-NEOs targets from the MIT-UH-IRTF Joint Campaign for Spectral Reconnaissance. Our dataset includes near-infrared spectra of 187 ExploreNEOs targets (125 observations of 92 objects from our survey and 213 observations of 154 objects from the MIT survey). We identify a taxonomic class for each spectrum and use band parameter analysis to investigate the mineralogies for the S-, Q-, and V-complex objects. Our analysis suggests that for spectra that contain near-infrared data but lack the visible wavelength region, the Bus-DeMeo system misidentifies some S-types as Q-types. We find no correlation between spectral band parameters and ExploreNEOs albedos and diameters. We investigate the correlations of phase angle with band area ratio and near-infrared spectral slope. We find slightly negative Band Area Ratio (BAR) correlations with phase angle for Eros and Ivar, but a positive BAR correlation with phase angle for Ganymed.The results of our

  9. Cosmic Infrared Background Fluctuations in Deep Spitzer Infrared Array Camera Images: Data Processing and Analysis

    Science.gov (United States)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

    2010-01-01

    This paper provides a detailed description of the data reduction and analysis procedures that have been employed in our previous studies of spatial fluctuation of the cosmic infrared background (CIB) using deep Spitzer Infrared Array Camera observations. The self-calibration we apply removes a strong instrumental signal from the fluctuations that would otherwise corrupt the results. The procedures and results for masking bright sources and modeling faint sources down to levels set by the instrumental noise are presented. Various tests are performed to demonstrate that the resulting power spectra of these fields are not dominated by instrumental or procedural effects. These tests indicate that the large-scale (gsim30') fluctuations that remain in the deepest fields are not directly related to the galaxies that are bright enough to be individually detected. We provide the parameterization of these power spectra in terms of separate instrument noise, shot noise, and power-law components. We discuss the relationship between fluctuations measured at different wavelengths and depths, and the relations between constraints on the mean intensity of the CIB and its fluctuation spectrum. Consistent with growing evidence that the ~1-5 μm mean intensity of the CIB may not be as far above the integrated emission of resolved galaxies as has been reported in some analyses of DIRBE and IRTS observations, our measurements of spatial fluctuations of the CIB intensity indicate the mean emission from the objects producing the fluctuations is quite low (gsim1 nW m-2 sr-1 at 3-5 μm), and thus consistent with current γ-ray absorption constraints. The source of the fluctuations may be high-z Population III objects, or a more local component of very low luminosity objects with clustering properties that differ from the resolved galaxies. Finally, we discuss the prospects of the upcoming space-based surveys to directly measure the epochs inhabited by the populations producing these source

  10. RESONANT CLUMPING AND SUBSTRUCTURE IN GALACTIC DISKS

    International Nuclear Information System (INIS)

    Molloy, Matthew; Smith, Martin C.; Shen, Juntai; Evans, N. Wyn

    2015-01-01

    We describe a method to extract resonant orbits from N-body simulations, exploiting the fact that they close in frames rotating with a constant pattern speed. Our method is applied to the N-body simulation of the Milky Way by Shen et al. This simulation hosts a massive bar, which drives strong resonances and persistent angular momentum exchange. Resonant orbits are found throughout the disk, both close to the bar and out to the very edges of the disk. Using Fourier spectrograms, we demonstrate that the bar is driving kinematic substructure even in the very outer parts of the disk. We identify two major orbit families in the outskirts of the disk, one of which makes significant contributions to the kinematic landscape, namely, the m:l = 3:−2 family, resonating with the bar. A mechanism is described that produces bimodal distributions of Galactocentric radial velocities at selected azimuths in the outer disk. It occurs as a result of the temporal coherence of particles on the 3:−2 resonant orbits, which causes them to arrive simultaneously at pericenter or apocenter. This resonant clumping, due to the in-phase motion of the particles through their epicycle, leads to both inward and outward moving groups that belong to the same orbital family and consequently produce bimodal radial velocity distributions. This is a possible explanation of the bimodal velocity distributions observed toward the Galactic anticenter by Liu et al. Another consequence is that transient overdensities appear and dissipate (in a symmetric fashion), resulting in a periodic pulsing of the disk’s surface density

  11. Assessment of galactic cosmic ray models

    Science.gov (United States)

    Mrigakshi, Alankrita Isha; Matthiä, Daniel; Berger, Thomas; Reitz, Günther; Wimmer-Schweingruber, Robert F.

    2012-08-01

    Among several factors involved in the development of a manned space mission concept, the astronauts' health is a major concern that needs to be considered carefully. Galactic cosmic rays (GCRs), which mainly consist of high-energetic nuclei ranging from hydrogen to iron and beyond, pose a major radiation health risk in long-term space missions. It is therefore required to assess the radiation exposure of astronauts in order to estimate their radiation risks. This can be done either by performing direct measurements or by making computer based simulations from which the dose can be derived. A necessary prerequisite for an accurate estimation of the exposure using simulations is a reliable description of the GCR spectra. The aim of this work is to compare GCR models and to test their applicability for the exposure assessment of astronauts. To achieve this, commonly used models capable of describing both light and heavy GCR particle spectra were evaluated by investigating the model spectra for various particles over several decades. The updated Badhwar-O'Neill model published in the year 2010, CREME2009 which uses the International Standard model for GCR, CREME96 and the Burger-Usoskin model were examined. Hydrogen, helium, oxygen and iron nuclei spectra calculated by the different models are compared with measurements from various high-altitude balloon and space-borne experiments. During certain epochs in the last decade, there are large discrepancies between the GCR energy spectra described by the models and the measurements. All the models exhibit weaknesses in describing the increased GCR flux that was observed in 2009-2010.

  12. FROM GALACTIC TO EXTRAGALACTIC JETS: A REVIEW

    Directory of Open Access Journals (Sweden)

    James H. Beall

    2013-12-01

    Full Text Available An analysis of the data that have recently become available from observing campaigns, including VLA, VLBA, and satellite instruments, shows some remarkable similarities and significant differences in the data from some epochs of galactic microquasars, including GRS 1915+105, the concurrent radio and X-ray data [3] on Centaurus A (NGC 5128, 3C120 [35], and 3C454.3 as reported by Bonning et al. [16], which showed the first results from the Fermi Space Telescope for the concurrent variability at optical, UV, IR, and g-ray variability of that source. In combination with observations from microquasars and quasars from the MOJAVE Collaboration [32], these data provide time-dependent evolutions of radio data at mas (i.e., parsec for AGNs, and Astronomical Unit scales for microquasars. These sources all show a remarkable richness of patterns of variability for astrophysical jets across the entire electromagnetic spectrum. It is likely that these patterns of variability arise from the complex structures through which the jets propagate, but it is also possible that the jets constitution, initial energy, and collimation have significant observational consequences. On the other hand, Ulrich et al. [42] suggest that this picture is complicated for radio-quiet AGN by the presence of significant emission from accretion disks in those sources. Consistent with the jet-ambient-medium hypothesis, the observed concurrent radio and X-ray variability of Centaurus A [3] could have been caused by the launch of a jet element from Cen A’s central source and that jet’s interaction with the interstellar medium in the core region of that galaxy.

  13. ON THE FORMATION OF GALACTIC THICK DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Minchev, I.; Streich, D.; Scannapieco, C.; De Jong, R. S.; Steinmetz, M. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Martig, M. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)

    2015-05-01

    Recent spectroscopic observations in the Milky Way suggest that the chemically defined thick disk (stars that have high [α/Fe] ratios and are thus old) has a significantly smaller scale-length than the thin disk. This is in apparent contradiction with observations of external edge-on galaxies, where the thin and thick components have comparable scale-lengths. Moreover, while observed disks do not flare (scale-height does not increase with radius), numerical simulations suggest that disk flaring is unavoidable, resulting from both environmental effects and secular evolution. Here we address these problems by studying two different suites of simulated galactic disks formed in the cosmological context. We show that the scale-heights of coeval populations always increase with radius. However, the total population can be decomposed morphologically into thin and thick disks, which do not flare. We relate this to the disk inside-out formation, where younger populations have increasingly larger scale-lengths and flare at progressively larger radii. In this new picture, thick disks are composed of the imbedded flares of mono-age stellar populations. Assuming that disks form inside out, we predict that morphologically defined thick disks must show a decrease in age (or [α/Fe] ratios) with radius and that coeval populations should always flare. This also explains the observed inversion in the metallicity and [α/Fe] gradients for stars away from the disk midplane in the Milky Way. The results of this work are directly linked to, and can be seen as evidence of, inside-out disk growth.

  14. Deciphering Galactic Hydrogen with 21-SPONGE

    Science.gov (United States)

    Murray, Claire; Stanimirovic, Snezana; Goss, Miller; Heiles, Carl E.; Miller Dickey, John; Lindner, Robert; Babler, Brian L.

    2017-01-01

    Neutral hydrogen (HI) in the interstellar medium (ISM) is crucial to the life cycles of galaxies. The balance between disparate phases of HI -- including the cold neutral (CNM) and warm neutral (WNM) medium -- governs the formation of dense, star-forming material, and reflects the nature of feedback in galaxies. To probe the multi-phase structure of HI, we present results from 21-SPONGE: the largest and most sensitive survey for Galactic HI absorption ever at the Karl G. Jansky Very Large Array (VLA). Complemented by HI emission from the Arecibo Observatory, 21-SPONGE is uniquely sensitive to CNM and WNM temperatures from 10-104 K and column densities from 1018-1022 cm-2. Despite our unprecedented sensitivity, the maximum temperature we detect for individual spectral lines is Ts~1500 K, although stacking analysis of 21-SPONGE absorption lines indicates the presence of pervasive, high-Ts WNM population with Ts~7000 K. To understand the physics underlying these results, we developed Autonomous Gaussian Decomposition (AGD), a Python-based tool for efficiently and objectively analyzing spectral lines. By applying AGD to 21-SPONGE and 1000s of synthetic HI spectra from 3D numerical simulations, we correct our measurements for completeness and observational biases. We further prove that we can successfully recover the temperatures and densities of real clouds along simulated lines of sight. In addition, we show that absorption line shapes are sensitive to the strength and topology of the Lyman alpha radiation field and its role in HI excitation, which are poorly-constrained yet important for understanding the energy balance of the ISM. Our results are among the first to statistically quantify the success of observational methods at reproducing true HI properties, and represent crucial steps towards understanding the role of HI in star formation.

  15. Dark Matter Annihilation at the Galactic Center

    Energy Technology Data Exchange (ETDEWEB)

    Linden, Timothy Ryan [Univ. of California, Santa Cruz, CA (United States)

    2013-06-01

    Observations by the WMAP and PLANCK satellites have provided extraordinarily accurate observations on the densities of baryonic matter, dark matter, and dark energy in the universe. These observations indicate that our universe is composed of approximately ve times as much dark matter as baryonic matter. However, e orts to detect a particle responsible for the energy density of dark matter have been unsuccessful. Theoretical models have indicated that a leading candidate for the dark matter is the lightest supersymmetric particle, which may be stable due to a conserved R-parity. This dark matter particle would still be capable of interacting with baryons via weak-force interactions in the early universe, a process which was found to naturally explain the observed relic abundance of dark matter today. These residual annihilations can persist, albeit at a much lower rate, in the present universe, providing a detectable signal from dark matter annihilation events which occur throughout the universe. Simulations calculating the distribution of dark matter in our galaxy almost universally predict the galactic center of the Milky Way Galaxy (GC) to provide the brightest signal from dark matter annihilation due to its relative proximity and large simulated dark matter density. Recent advances in telescope technology have allowed for the rst multiwavelength analysis of the GC, with suitable e ective exposure, angular resolution, and energy resolution in order to detect dark matter particles with properties similar to those predicted by the WIMP miracle. In this work, I describe ongoing e orts which have successfully detected an excess in -ray emission from the region immediately surrounding the GC, which is di cult to describe in terms of standard di use emission predicted in the GC region. While the jury is still out on any dark matter interpretation of this excess, I describe several related observations which may indicate a dark matter origin. Finally, I discuss the

  16. Evolution of the Oort Cloud under Galactic Perturbations

    Science.gov (United States)

    Higuchi, A.; Kokubo, E.; Mukai, T.

    2005-08-01

    The Oort cloud is a spherical comet reservoir surrounding the solar system. There is general agreement that the Oort cloud comets are the residual planetesimals of planet formation. The standard scenario of the Oort cloud formation consists of two dynamical stages: (1) giant planets raise the aphelia of planetesimals to the outer region of the solar system and (2) the galactic tide, passing stars, and giant molecular clouds pull up their perihelia out of the planetary region and randomize their inclinations. Here we show the orbital evolution of planetesimals due to the galactic tide. Planetesimals with large aphelion distances change their perihelion distances toward the outside of the planetary region by the galactic tide and become members of the Oort cloud. We consider only the vertical component of the galactic tide because it is dominant compared to other components. Then, under such an axi-symmetric assumption, some planetesimals may show the librations around ω (argument of perihelion)=π /2 or 3π /2 (the Kozai mechanism). The alternate increases of eccentricity and inclination of the Kozai mechanism are effective to form the Oort cloud. Using the secular perturbation theory, we can understand the motion of the planetesimals analytically. We applied the Kozai mechanism to the galactic tide and found that the galactic tide raise perihelia and randomize inclinations of planetesimals with semimajor axes larger than ˜ 103 AU in 5Gyr. We take into account time evolution of the local galactic density, which is thought to be denser in the early stage of the sun than the current one. This work was supported by the 21st Century COE Program Origin and Evolution of Planetary Systems of the Ministry of Education, Culture, Sports, Science, and Technology, Japan, and JSPS Research Fellowship for Young Scientists.

  17. OSSE observations of galactic 511 keV annihilation radiation

    Science.gov (United States)

    Purcell, W. R.; Grabelsky, D. A.; Johnson, W. N.; Jung, G. V.; Kinzer, R. L.; Kurfess, J. D.; Strickman, M. S.; Ulmer, M. P.

    1992-01-01

    The Oriented Scintillation Spectrometer Experiment (OSSE) on the Compton Gamma-Ray Observatory has performed several observations of the galactic plane and galactic center region to measure the distribution of galactic 511 keV positron annihilation radiation. Preliminary analysis of data collected during the observation of the galactic center region over the period 13-24 Jun. 1991, indicates the presence of a 511 keV line and positronium continuum superimposed on a power-law continuum. The line of flux was found to be (2.7 +/- 0.5) x 10(exp -4) gamma/sq cm sec, with a positronium fraction of (0.9 +/- 0.2). The 3(sigma) upper limit to daily variations in the 511 keV line flux from the mean during the observation interval is 3 x 10(exp -4) gamma/sq cm sec. If all of the observed annihilation radiation is assumed to originate from the x-ray source 1E 1740.7-2942, the corresponding 511 keV line flux would be (3.0 +/- 0.6) x 10(exp -4) gamma/sq cm sec. The 3(sigma) upper limit for 511 keV line emission from the x-ray binary GX1+4 is 6 x 10(exp -4) gamma/sq cm sec. Results from the galactic plane observations at galactic longitudes of 25 degrees (16-21 Aug. 1991) and 339 degrees (6-11 Sep. 1991) suggest that the emission is concentrated near the galactic center. The observations and the preliminary results are described.

  18. Geometry, mechanics, and dynamics the legacy of Jerry Marsden

    CERN Document Server

    Holm, Darryl; Patrick, George; Ratiu, Tudor

    2015-01-01

    This book illustrates the broad range of Jerry Marsden’s mathematical legacy in areas of geometry, mechanics, and dynamics, from very pure mathematics to very applied, but always with a geometric perspective. Each contribution develops its material from the viewpoint of geometric mechanics beginning at the very foundations, introducing readers to modern issues via illustrations in a wide range of topics. The twenty refereed papers contained in this volume are based on lectures and research performed during the month of July 2012 at the Fields Institute for Research in Mathematical Sciences, in a program in honor of Marsden's legacy. The unified treatment of the wide breadth of topics treated in this book will be of interest to both experts and novices in geometric mechanics. Experts will recognize applications of their own familiar concepts and methods in a wide variety of fields, some of which they may never have approached from a geometric viewpoint. Novices may choose topics that interest them among the ...

  19. THE NUCLEAR INFRARED EMISSION OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Mason, R. E. [Gemini Observatory, Northern Operations Center, 670 N. A' ohoku Place, Hilo, HI 96720 (United States); Lopez-Rodriguez, E.; Packham, C. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, P.O. Box 112055, Gainesville, FL 32611 (United States); Alonso-Herrero, A. [Instituto de Fisica de Cantabria, CSIC-UC, Avenida de los Castros s/n, 39005 Santander (Spain); Levenson, N. A.; Radomski, J. [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Ramos Almeida, C. [Instituto de Astrofisica de Canarias, C/Via Lactea, s/n, E-38205, La Laguna, Tenerife (Spain); Colina, L. [Departamento de Astrofisica, Centro de Astrobiologia (CSIC/INTA), Instituto Nacional de Tecnica Aeroespacial, Crta de Torrejon a Ajalvir, km 4, 28850 Torrejon de Ardoz, Madrid (Spain); Elitzur, M. [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Aretxaga, I. [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla (Mexico); Roche, P. F. [Astrophysics, Department of Physics, University of Oxford, DWB, Keble Road, Oxford OX1 3RH (United Kingdom); Oi, N. [Department of Astronomy, School of Science, Graduate University for Advanced Studies (SOKENDAI), Mitaka, Tokyo 181-8588 (Japan)

    2012-07-15

    We present high-resolution mid-infrared (MIR) imaging, nuclear spectral energy distributions (SEDs), and archival Spitzer spectra for 22 low-luminosity active galactic nuclei (LLAGNs; L{sub bol} {approx}< 10{sup 42} erg s{sup -1}). Infrared (IR) observations may advance our understanding of the accretion flows in LLAGNs, the fate of the obscuring torus at low accretion rates, and, perhaps, the star formation histories of these objects. However, while comprehensively studied in higher-luminosity Seyferts and quasars, the nuclear IR properties of LLAGNs have not yet been well determined. We separate the present LLAGN sample into three categories depending on their Eddington ratio and radio emission, finding different IR characteristics for each class. (1) At the low-luminosity, low-Eddington-ratio (log L{sub bol}/L{sub Edd} < -4.6) end of the sample, we identify 'host-dominated' galaxies with strong polycyclic aromatic hydrocarbon bands that may indicate active (circum-)nuclear star formation. (2) Some very radio-loud objects are also present at these low Eddington ratios. The IR emission in these nuclei is dominated by synchrotron radiation, and some are likely to be unobscured type 2 AGNs that genuinely lack a broad-line region. (3) At higher Eddington ratios, strong, compact nuclear sources are visible in the MIR images. The nuclear SEDs of these galaxies are diverse; some resemble typical Seyfert nuclei, while others lack a well-defined MIR 'dust bump'. Strong silicate emission is present in many of these objects. We speculate that this, together with high ratios of silicate strength to hydrogen column density, could suggest optically thin dust and low dust-to-gas ratios, in accordance with model predictions that LLAGNs do not host a Seyfert-like obscuring torus. We anticipate that detailed modeling of the new data and SEDs in terms of accretion disk, jet, radiatively inefficient accretion flow, and torus components will provide further

  20. Georges Lema\\^itre: Life, Science and Legacy

    OpenAIRE

    Mitton, Simon

    2016-01-01

    This paper celebrates the remarkable life, science and legacy of Abb\\'e Georges Lema\\^itre, the Belgian cleric and professor of physics; he was the architect of the fireworks model for the origin of the universe. He died half a century ago, three days after learning that Arno Penzias and Robert Wilson had discovered the cosmic microwave background. Despite being gravely ill from leukaemia, Lema\\^itre lucidly praised this news, which confirmed the explosive genesis of our universe.

  1. Legacy Radioactive Waste Management Program in the Netherlands: An Overview

    International Nuclear Information System (INIS)

    Ménard, Gaël

    2016-01-01

    Petten site legacy waste: • sorted on waste streams, from the less to the more heterogeneous; • footprint reduction by sorting according to activity; • first two waste streams: limited number of material; • characterized using gamma measurements and computational nuclide vectors. •Waste acceptance criteria: modus vivendi with the storage facility and third parties (based on characterization results); • More heterogeneous waste: more complex by definition → optimization, development and adaptation of the characterization

  2. The Legacy of the High Reliability Organizations Project

    OpenAIRE

    Bourrier, Mathilde

    2011-01-01

    This article looks back over two decades of work pioneered by Todd LaPorte and colleagues, under the banner of High Reliability Theory (HRT). The article revisits the American roots of the Berkeley-based group and comments on its early and decisive fieldwork choices. It revisits some of the elements that emerged through the controversy around findings and implications of HRT. It discusses the legacy of HRT and the ethnographical impetus given to "normal operations" studies. The use of ethnogr...

  3. From Boston to the Balkans: Olmsted’s Emerald Legacy

    Directory of Open Access Journals (Sweden)

    Christina Luke

    2013-01-01

    Full Text Available This article explores the legacy of landscape architect Fredrick Law Olmsted on modern cultural tourism policies. The author explains the involvement of Olmsted in the founding of Yosemite National Park, and describes the influence of this experience on his later work on the Emerald Necklace parks project in Boston. This became a model for natural and cultural corridors worldwide, including those in the Balkans and Turkey.

  4. Paralympic Games: History and Legacy of a Global Movement.

    Science.gov (United States)

    Legg, David

    2018-05-01

    The Paralympic Games have an interesting history that began after World War II. The Games and movement have been impacted by and have had an impact on society and the larger able-bodied sport system. The future of the Games and movement is also further impacted by larger cultural shifts, and the Games themselves have potentially left lasting legacies for the host cities and persons with impairment worldwide. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. The influence of marketing scholarship's legacy on nonprofit marketing

    OpenAIRE

    Wymer, Walter

    2013-01-01

    This inquiry contributes to the literature on the development of “nonprofit marketing thought” by describing how the field’s early period established a legacy effect on nonprofit marketing scholarship to the present day. This qualitative work uses a wide variety of sources from a protracted historical period in order to more fully inform a perspective on the relevant issues that have influenced the development of nonprofit marketing scholarship. The investigation suggests that, although the d...

  6. The Roman Empire legacy of Galen (129-200 AD).

    Science.gov (United States)

    Shoja, Mohammadali M; Tubbs, R Shane; Ghabili, Kamyar; Griessenauer, Christoph J; Balch, Margaret Wood; Cuceu, Mariana

    2015-01-01

    Galen of Pergamum was the physician of Roman Emperors and contributed to our early understanding of medicine and anatomy. Herein, we present a short biography of Galen and review his multiple contributions to medicine and anatomy. Although it has been almost 2,000 years since Galen walked the streets of the Roman Empire, his legacy continues via multiple eponyms that bare his name.

  7. Probing Large-scale Coherence between Spitzer IR and Chandra X-Ray Source-subtracted Cosmic Backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Cappelluti, N.; Urry, M. [Yale Center for Astronomy and Astrophysics, P.O. Box 208120, New Haven, CT 06520 (United States); Arendt, R. [University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Kashlinsky, A. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Li, Y.; Hasinger, G. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Helgason, K. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Natarajan, P. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Finoguenov, A. [Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, D-85741, Garching bei München (Germany)

    2017-09-20

    We present new measurements of the large-scale clustering component of the cross-power spectra of the source-subtracted Spitzer -IRAC cosmic infrared background and Chandra -ACIS cosmic X-ray background surface brightness fluctuations Our investigation uses data from the Chandra Deep Field South, Hubble Deep Field North, Extended Groth Strip/AEGIS field, and UDS/SXDF surveys, comprising 1160 Spitzer hours and ∼12 Ms of Chandra data collected over a total area of 0.3 deg{sup 2}. We report the first (>5 σ ) detection of a cross-power signal on large angular scales >20″ between [0.5–2] keV and the 3.6 and 4.5 μ m bands, at ∼5 σ and 6.3 σ significance, respectively. The correlation with harder X-ray bands is marginally significant. Comparing the new observations with existing models for the contribution of the known unmasked source population at z < 7, we find an excess of about an order of magnitude at 5 σ confidence. We discuss possible interpretations for the origin of this excess in terms of the contribution from accreting early black holes (BHs), including both direct collapse BHs and primordial BHs, as well as from scattering in the interstellar medium and intra-halo light.

  8. OBSERVATIONAL 5-20 μm INTERSTELLAR EXTINCTION CURVES TOWARD STAR-FORMING REGIONS DERIVED FROM SPITZER IRS SPECTRA

    International Nuclear Information System (INIS)

    McClure, M.

    2009-01-01

    Using Spitzer Infrared Spectrograph observations of G0-M4 III stars behind dark clouds, I construct 5-20 μm empirical extinction curves for 0.3 ≤ A K V between ∼3 and 50. For A K K > 1, the curve exhibits lower contrast between the silicate and absorption continuum, develops ice absorption, and lies closer to the Weingartner and Draine R V = 5.5 Case B curve, a result which is consistent with that of Flaherty et al. and Chiar et al. Recently, work using Spitzer Infrared Array Camera data by Chapman et al. independently reaches a similar conclusion that the shape of the extinction curve changes as a function of increasing A K . By calculating the optical depths of the 9.7 μm silicate and 6.0, 6.8, and 15.2 μm ice features, I determine that a process involving ice is responsible for the changing shape of the extinction curve and speculate that this process is a coagulation of ice-mantled grains rather than ice-mantled grains alone.

  9. Revisiting the Phase Curves of WASP-43b: Confronting Re-analyzed Spitzer Data with Cloudy Atmospheres

    Science.gov (United States)

    Mendonça, João M.; Malik, Matej; Demory, Brice-Olivier; Heng, Kevin

    2018-04-01

    Recently acquired Hubble and Spitzer phase curves of the short-period hot Jupiter WASP-43b make it an ideal target for confronting theory with data. On the observational front, we re-analyze the 3.6 and 4.5 μm Spitzer phase curves and demonstrate that our improved analysis better removes residual red noise due to intra-pixel sensitivity, which leads to greater fluxes emanating from the nightside of WASP-43b, thus reducing the tension between theory and data. On the theoretical front, we construct cloud-free and cloudy atmospheres of WASP-43b using our Global Circulation Model (GCM), THOR, which solves the non-hydrostatic Euler equations (compared to GCMs that typically solve the hydrostatic primitive equations). The cloud-free atmosphere produces a reasonable fit to the dayside emission spectrum. The multi-phase emission spectra constrain the cloud deck to be confined to the nightside and have a finite cloud-top pressure. The multi-wavelength phase curves are naturally consistent with our cloudy atmospheres, except for the 4.5 μm phase curve, which requires the presence of enhanced carbon dioxide in the atmosphere of WASP-43b. Multi-phase emission spectra at higher spectral resolution, as may be obtained using the James Webb Space Telescope, and a reflected-light phase curve at visible wavelengths would further constrain the properties of clouds in WASP-43b.

  10. Probing Large-scale Coherence between Spitzer IR and Chandra X-Ray Source-subtracted Cosmic Backgrounds

    Science.gov (United States)

    Cappelluti, N.; Arendt, R.; Kashlinsky, A.; Li, Y.; Hasinger, G.; Helgason, K.; Urry, M.; Natarajan, P.; Finoguenov, A.

    2017-09-01

    We present new measurements of the large-scale clustering component of the cross-power spectra of the source-subtracted Spitzer-IRAC cosmic infrared background and Chandra-ACIS cosmic X-ray background surface brightness fluctuations Our investigation uses data from the Chandra Deep Field South, Hubble Deep Field North, Extended Groth Strip/AEGIS field, and UDS/SXDF surveys, comprising 1160 Spitzer hours and ˜12 Ms of Chandra data collected over a total area of 0.3 deg2. We report the first (>5σ) detection of a cross-power signal on large angular scales >20″ between [0.5-2] keV and the 3.6 and 4.5 μm bands, at ˜5σ and 6.3σ significance, respectively. The correlation with harder X-ray bands is marginally significant. Comparing the new observations with existing models for the contribution of the known unmasked source population at z < 7, we find an excess of about an order of magnitude at 5σ confidence. We discuss possible interpretations for the origin of this excess in terms of the contribution from accreting early black holes (BHs), including both direct collapse BHs and primordial BHs, as well as from scattering in the interstellar medium and intra-halo light.

  11. SPITZER AS A MICROLENS PARALLAX SATELLITE: MASS MEASUREMENT FOR THE OGLE-2014-BLG-0124L PLANET AND ITS HOST STAR

    Energy Technology Data Exchange (ETDEWEB)

    Udalski, A.; Skowron, J.; Kozłowski, S.; Poleski, R.; Pietrukowicz, P.; Pietrzyński, G.; Szymański, M. K.; Mróz, P.; Soszyński, I.; Ulaczyk, K.; Wyrzykowski, Ł. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Gould, A.; Zhu, W.; Pogge, R. W. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Carey, S. [Spitzer Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Han, C. [Department of Physics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Calchi Novati, S. [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States)

    2015-02-01

    We combine Spitzer and ground-based observations to measure the microlens parallax vector π{sub E}, and thus the mass and distance of OGLE-2014-BLG-0124L, making it the first microlensing planetary system with a space-based parallax measurement. The planet and star have masses of m ∼ 0.5 M {sub jup} and M ∼ 0.7 M {sub ☉} and are separated by a ∼ 3.1 AU in projection. The main source of uncertainty in all of these numbers (approximately 30%, 30%, and 20%) is the relatively poor measurement of the Einstein radius θ{sub E}, rather than uncertainty in π{sub E}, which is measured with 2.5% precision. This compares to 22% based on OGLE data alone, implying that the Spitzer data provide not only a substantial improvement in the precision of the π{sub E} measurement, but also the first independent test of a ground-based π{sub E} measurement.

  12. Spitzer IRS (8-30 micron) Spectra of Basaltic Asteroids 1459 Magnya and 956 Elisa: Mineralogy and Thermal Properties

    Science.gov (United States)

    Lim, Lucy F.; Emery, J. P.; Moskovitz, N. A.

    2009-01-01

    We report preliminary results from Spitzer IRS (Infrared Spectrograph) spectroscopy of 956 Elisa, 1459 Magnya, and other small basaltic asteroids with the Spitzer IRS. Program targets include members of the dynamical family of the unique large differentiated asteroid 4 Vesta ("Vestoids"), several outer-main-belt basaltic asteroids whose orbits exclude them from originating on 4 Vesta, and the basaltic near-Earth asteroid 4055 Magellan. The preliminary thermal model (STM) fit to the 5--35 micron spectrum of 956 Elisa gives a radius of 5.4 +/- 0.3 km and a subsolar- point temperature of 282.2 +/- 0.5 K. This temperature corresponds to eta approximately equals 1.06 +/- 0.02, which is substantially higher than the eta approximately equals 0.756 characteristic of large main-belt asteroids. Unlike 4 Vesta and other large asteroids, therefore, 956 Elisa has significant thermal inertia in its surface layer. The wavelength of the Christiansen feature (emissivity maximum near 9 micron), the positions and shapes of the narrow maxima (10 micron, 11 micron) within the broad 9--14 micron silicate band, and the 19--20 micron minimum are consistent with features found in the laboratory spectra of diogenites and of low-Ca pyroxenes of similar composition (Wo<5, En50-En75).

  13. A Search to Uncover the Infrared Excess (IRXS) Sources in the Spitzer Enhanced Imaging Products (SEIP) Catalog

    Science.gov (United States)

    Rowe, Jamie Lynn; Duranko, Gary; Gorjian, Varoujan; Lineberger, Howard; Orr, Laura; Adewole, Ayomikun; Bradford, Eric; Douglas, Alea; Kohl, Steven; Larson, Lillia; Lascola, Gus; Orr, Quinton; Scott, Mekai; Walston, Joseph; Wang, Xian

    2018-01-01

    The Spitzer Enhanced Imaging Products catalog (SEIP) is a collection of nearly 42 million point sources obtained by the Spitzer Space Telescope during its 5+ year cryogenic mission. Strasburger et al (2014) isolated sources with a signal-to-noise ratio (SNR) >10 in five infrared (IR) wavelength channels (3.6, 4.5, 5.8, 8 and 24 microns) to begin a search for sources with infrared excess (IRXS). They found 76 objects that were never catalogued before. Based on this success, we intend to dig deeper into the catalog in an attempt to find more IRXS sources, specifically by lowering the SNR on the 3.6, 4.5, and 24 micron channels. The ultimate goal is to use this large sample to seek rare astrophysical sources that are transitional in nature and evolutionarily very important.Our filtering of the database at SNR > 5 yielded 461,000 sources. This was further evaluated and reduced to only the most interesting based on source location on a [3.6]-[4.5] vs [4.5]-[24] color-color diagram. We chose a sample of 985 extreme IRXS sources for further inspection. All of these candidate sources were visually inspected and cross-referenced against known sources in existing databases, resulting in a list of highly reliable IRXS sources.These sources will prove important in the study of galaxy and stellar evolution, and will serve as a starting point for further investigation.

  14. APOGEE-2: The Second Phase of the Apache Point Observatory Galactic Evolution Experiment in SDSS-IV

    Science.gov (United States)

    Sobeck, Jennifer; Majewski, S.; Hearty, F.; Schiavon, R. P.; Holtzman, J. A.; Johnson, J.; Frinchaboy, P. M.; Skrutskie, M. F.; Munoz, R.; Pinsonneault, M. H.; Nidever, D. L.; Zasowski, G.; Garcia Perez, A.; Fabbian, D.; Meza Cofre, A.; Cunha, K. M.; Smith, V. V.; Chiappini, C.; Beers, T. C.; Steinmetz, M.; Anders, F.; Bizyaev, D.; Roman, A.; Fleming, S. W.; Crane, J. D.; SDSS-IV/APOGEE-2 Collaboration

    2014-01-01

    The second phase of the Apache Point Observatory Galactic Evolution Experiment (APOGEE-2), a part of the Sloan Digital Sky Survey IV (SDSS-IV), will commence operations in 2014. APOGEE-2 represents a significant expansion over APOGEE-1, not only in the size of the stellar sample, but also in the coverage of the sky through observations in both the Northern and Southern Hemispheres. Observations on the 2.5m Sloan Foundation Telescope of the Apache Point Observatory (APOGEE-2N) will continue immediately after the conclusion of APOGEE-1, to be followed by observations with the 2.5m du Pont Telescope of the Las Campanas Observatory (APOGEE-2S) within three years. Over the six-year lifetime of the project, high resolution (R˜22,500), high signal-to-noise (≥100) spectroscopic data in the H-band wavelength regime (1.51-1.69 μm) will be obtained for several hundred thousand stars, more than tripling the total APOGEE-1 sample. Accurate radial velocities and detailed chemical compositions will be generated for target stars in the main Galactic components (bulge, disk, and halo), open/globular clusters, and satellite dwarf galaxies. The spectroscopic follow-up program of Kepler targets with the APOGEE-2N instrument will be continued and expanded. APOGEE-2 will significantly extend and enhance the APOGEE-1 legacy of scientific contributions to understanding the origin and evolution of the elements, the assembly and formation history of galaxies like the Milky Way, and fundamental stellar astrophysics.

  15. Modeling X-ray Emission of Galactic Winds

    Science.gov (United States)

    Tomesh, Teague; Gould Zweibel, Ellen; Bustard, Chad

    2017-06-01

    Despite galaxies being the main players on the cosmological scene, and our living inside of one, the processes of evolution which create these structures are still a mystery. Galactic winds are an important component of galaxy evolution and the mechanisms which drive these outflows have yet to be explained. We have incorporated x-ray production into a preexisting model of galactic outflows in order to generate predictions of x-ray luminosity to test current wind theories against observations. Specifically, the model is a representation of thermally driven winds. First, we incorporated the equations for x-ray luminosity into the wind model and tested its effects over a wide range of parameter space. We then created models to match the parameters of several cool galactic outflows previously studied. Finally, we searched the relevant literature for observations of these galaxies that we could use to compare with our predicted luminosities. Our models consistently predicted luminosities within a factor of two of the observed values. This led to the conclusion that if the hot and cool gas are coupled then thermal energy may play a role in the driving of these winds. Unraveling this mystery will be key to understanding galactic outflows and galactic evolution overall.

  16. TESTING GALACTIC MAGNETIC FIELD MODELS USING NEAR-INFRARED POLARIMETRY

    International Nuclear Information System (INIS)

    Pavel, Michael D.; Clemens, D. P.; Pinnick, A. F.

    2012-01-01

    This work combines new observations of NIR starlight linear polarimetry with previously simulated observations in order to constrain dynamo models of the Galactic magnetic field. Polarimetric observations were obtained with the Mimir instrument on the Perkins Telescope in Flagstaff, AZ, along a line of constant Galactic longitude (l = 150°) with 17 pointings of the 10' × 10' field of view between –75° < b < 10°, with more frequent pointings toward the Galactic midplane. A total of 10,962 stars were photometrically measured and 1116 had usable polarizations. The observed distribution of polarization position angles with Galactic latitude and the cumulative distribution function of the measured polarizations are compared to predicted values. While the predictions lack the effects of turbulence and are therefore idealized, this comparison allows significant rejection of A0-type magnetic field models. S0 and disk-even halo-odd magnetic field geometries are also rejected by the observations, but at lower significance. New predictions of spiral-type, axisymmetric magnetic fields, when combined with these new NIR observations, constrain the Galactic magnetic field spiral pitch angle to –6° ± 2°.

  17. Architecture-driven Migration of Legacy Systems to Cloud-enabled Software

    DEFF Research Database (Denmark)

    Ahmad, Aakash; Babar, Muhammad Ali

    2014-01-01

    With the widespread adoption of cloud computing, an increasing number of organizations view it as an important business strategy to evolve their legacy applications to cloud-enabled infrastructures. We present a framework, named Legacy-to-Cloud Migration Horseshoe, for supporting the migration...... of legacy systems to cloud computing. The framework leverages the software reengineering concepts that aim to recover the architecture from legacy source code. Then the framework exploits the software evolution concepts to support architecture-driven migration of legacy systems to cloud-based architectures....... The Legacy-to-Cloud Migration Horseshoe comprises of four processes: (i) architecture migration planning, (ii) architecture recovery and consistency, (iii) architecture transformation and (iv) architecture-based development of cloud-enabled software. We aim to discover, document and apply the migration...

  18. Sport mega-events: can legacies and development be equitable and sustainable?

    Directory of Open Access Journals (Sweden)

    Jay Coakley

    2013-09-01

    Full Text Available Sport mega-events (SMEs involve struggles to determine the definition of legacy and the outcome priorities that guide legacy planning, funding, and implementation processes. History shows that legacies reflect the interests of capital, and legacy benefits are enjoyed primarily, if not exclusively, by powerful business interests, a few political leaders, and organizations that govern high performance sports. This paper addresses challenges faced by cities and countries that host SMEs, and shows that fair and equitable legacies and developmental outcomes are achieved only when the voices and interests of the general population are taken into account and given priority during the process of planning, funding and implementation. It also explains how full representation in the process of defining and achieving legacies and developmental outcomes may be undermined by populist beliefs about the power of sport.

  19. The Structure of Active Galactic Nuclei

    Science.gov (United States)

    Kriss, Gerard A.

    1997-06-01

    We are continuing our systematic investigation of the nuclear structure of nearby active galactic nuclei (AGN). Upon completion, our study will characterize hypothetical constructs such as narrow-line clouds, obscuring tori, nuclear gas disks. and central black holes with physical measurements for a complete sample of nearby AGN. The major scientific goals of our program are: (1) the morphology of the NLR; (2) the physical conditions and dynamics of individual clouds in the NLR; (3) the structure and physical conditions of the warm reflecting gas; (4) the structure of the obscuring torus; (5) the population and morphology of nuclear disks/tori in AGN; (6) the physical conditions in nuclear disks; and (7) the masses of central black holes in AGN. We will use the Hubble Space Telescope (HST) to obtain high-resolution images and spatially resolved spectra. Far-UV spectroscopy of emission and absorption in the nuclear regions using HST/FOS and the Hopkins Ultraviolet Telescope (HUT) will help establish physical conditions in the absorbing and emitting gas. By correlating the dynamics and physical conditions of the gas with the morphology revealed through our imaging program, we will be able to examine mechanisms for fueling the central engine and transporting angular momentum. The kinematics of the nuclear gas disks may enable us to measure the mass of the central black hole. Contemporaneous X-ray observations using ASCA will further constrain the ionization structure of any absorbing material. Monitoring of variability in the UV and X-ray absorption will be used to determine the location of the absorbing gas, possibly in the outflowing warm reflecting gas, or the broad-line region, or the atmosphere of the obscuring torus. Supporting ground-based observations in the optical, near-IR, imaging polarimetry, and the radio will complete our picture of the nuclear structures. With a comprehensive survey of these characteristics in a complete sample of nearby AGN, our

  20. Overview of galactic results obtained by MAGIC

    Energy Technology Data Exchange (ETDEWEB)

    Zanin, Roberta

    2013-06-15

    MAGIC is a system of two atmospheric Cherenkov telescopes which explores the very-high-energy sky, from some tens of GeV up to tens of TeV. Located in the Canary island of La Palma, MAGIC has the lowest energy threshold among the instruments of its kind, well suited to study the still poorly explored energy band below 100 GeV. Although the space-borne gamma-ray telescope Fermi/LAT is sensitive up to 300 GeV, gamma-ray rates drop fast with increasing energy, so γ-ray collection areas larger than 10{sup 4}m{sup 2}, as those provided by grounds-based instruments, are crucial above a few GeV. The combination of MAGIC and Fermi/LAT observations have provided the first astrophysical spectra sampled in the inverse Compton peak region, resulting in a complete coverage from MeV up to TeV energies, as well as the discovery of a pulsed emission in the very-high-energy band. This paper focuses on the latest results on Galactic sources obtained by MAGIC which are highlighted by the detection of the pulsed gamma-ray emission from the Crab pulsar up to 400 GeV. In addition, we will present the morphological study on the W51 complex which allowed to pinpoint the location of the majority of the emission around the interaction point between the supernova remnant W51C and the star forming region W51B, but also to find a possible contribution from the associated pulsar wind nebula. Other important scientific achievements involve the Crab Nebula with an unprecedented spectrum covering three decades in energy starting from 50 GeV and a morphological study of the unidentified source HESS J1857+026 which supports the pulsar wind nebula scenario. Finally we will report on the searches of very-high-energy signals from gamma-ray binaries, mainly LS I 303+ and HESS J0632+057.

  1. Gravitational Theories near the Galactic Center

    Science.gov (United States)

    Kalita, Sanjeev

    2018-03-01

    Upcoming Extremely Large Telescopes (ELTs) are promising probes of gravity in or near the galactic center (GC). Effects of alternative theories of gravity, namely the Brans–Dicke theory (BDT) and f(R) gravity, are studied near the GC black hole by calculating departure from general relativity (GR) in periastron advance of the S stars and light deflection. For these estimations, black hole spin and quadrupole moments are taken in the ranges χ = 0.1–2.0 and {J}2={10}-6{--}2.0, respectively. Periastron advance ({\\dot{θ }}prec}) has been calculated for hypothetical S stars with orbital period one-fifth of S0-2 and eccentricity e = 0.8. The difference between BDT and GR ({{{Δ }}}th}{\\dot{θ }}prec}) lies in the range 10‑3–2.3 μas yr‑1, even for a large departure from GR. The difference between quadrupoles {J}2={10}-6 and J 2 = 2.0 lies in the range {{{Δ }}}{J2}{\\dot{θ }}prec}=0.268{--}0.281 μ {as} {yr}}-1. These ranges are not only outside the astrometric capability of the ELTs, but are also contaminated by stellar perturbations. Parameter degeneracy among χ, J 2, and {ω }BD} is discussed. For black hole–S-star distances, D LS = 100 and 50 au, the difference in light deflection between BDT and GR lies in the range d{(δ φ )}defl}={10}-5{--}{10}-1 μ {as}, making it difficult to distinguish them. From the relation between scalaron mass, {M}\\psi in f(R) gravity, and calculated d{(δ φ )}defl}, it is found that {M}\\psi ={10}-18{--}{10}-17 {eV} can form a stable “dark cloud” near the black hole. Scalarons with {10}-21 {eV} are found to bring d{(δ φ )}defl} close to the astrometric range of the ELTs. Prospects for these scalarons in the tests of gravity are discussed.

  2. Microwave spectral lines in galactic dust globules

    International Nuclear Information System (INIS)

    Martin, R.N.; Barrett, A.H.

    1978-01-01

    In order to better understand galactic dust globules, a program of mapping several molecular transitions in these clouds has been undertaken. The results of observations of the J=1→0 rotational transitions of CO, 13 CO, C 18 O, and CS, the J=2→1rotational transitions of CS and C 34 S, the J, K=1, 1 and J, K=2, 2 inversion transitions of NH 3 , the J/sub KKprime/=1 11 →1 10 and J/sub KKprime/=2 12 →2 11 transitions of H 2 CO, and the OH 2 Pi/sub 3/2/F=2→2 and F=1→1 transitions are reported here. Twelve globules have been selected for observation; seven of these were studied in detail and the remainder observed only sparsely. A strong positive correlation appears to exist between the spatial extent of the molecular emission (or absorption) and the optical features of the globule. Even the main isotope of CO shows this correlation between dust extinction and molecular emission. Close examination of the Palomar prints reveals dust wherever CO is observed, and CO is probably a good tracer of dust extinction.The simultaneous observation of many molecular transitions has proven useful in obtaining reliable physical parameters for the dust globules. For example, CO and NH 3 are reliable thermometers of the kinetic temperature, and CS and NH 3 are indicators of the total gas density. The kinetic temperatures of the globules are almost always approx.10 K, and the derived H 2 densities are 10/sup 3.4/-10/sup 4.5/ cm -3 . The density in the core of the globules could well be larger than these value, which represent an average for the entire cloud. The kinetic temperature appears uniform across each cloud (within a few kelvins), in agreement with theoretical predictions. All of the globules studied in detail appear to be gravitationally bound and collapsing objects. Rotation has been observed in at least two globules (B163 and B163 SW). The projected axis of rotation is in a direction opposite to that of the Galaxy

  3. TWO-COMPONENT GALACTIC BULGE PROBED WITH RENEWED GALACTIC CHEMICAL EVOLUTION MODEL

    International Nuclear Information System (INIS)

    Tsujimoto, Takuji; Bekki, Kenji

    2012-01-01

    Results of recent observations of the Galactic bulge demand that we discard a simple picture of its formation, suggesting the presence of two stellar populations represented by two peaks of stellar metallicity distribution (MDF) in the bulge. To assess this issue, we construct Galactic chemical evolution models that have been updated in two respects: first, the delay time distribution of Type Ia supernovae (SNe Ia) recently revealed by extensive SN Ia surveys is incorporated into the models. Second, the nucleosynthesis clock, the s-processing in asymptotic giant branch stars, is carefully considered in this study. This novel model first shows that the Galaxy feature tagged by the key elements, Mg, Fe, and Ba, for the bulge as well as thin and thick disks is compatible with a short-delay SN Ia. We present a successful modeling of a two-component bulge including the MDF and the evolutions of [Mg/Fe] and [Ba/Mg], and reveal its origin as follows. A metal-poor component (([Fe/H]) ∼ –0.5) is formed with a relatively short timescale of ∼1 Gyr. These properties are identical to the thick disk's characteristics in the solar vicinity. Subsequently from its remaining gas mixed with a gas flow from the disk outside the bulge, a metal-rich component (([Fe/H]) ∼ +0.3) is formed with a longer timescale (∼4 Gyr) together with a top-heavy initial mass function that might be identified with the thin disk component within the bulge.

  4. Ram pressure effects in the galactic plane and galactic dynamos in the no-z approximation

    Science.gov (United States)

    Moss, D.; Sokoloff, D.; Beck, R.

    2012-08-01

    Context. The magnetic field of galaxies is believed to be produced by internal dynamo action, but can be affected by motion of the galaxy through the surrounding medium. Observations of polarized radio emission of galaxies located in galaxy clusters have revealed noticeable features of large-scale magnetic configurations, including displacements of the magnetic structures from the optical images and tails, which are possible imprints of ram pressure effects arising from motion of the galaxies through the intracluster medium. Aims: We present a quantitative dynamo model, which attempts to describe the above effects. In contrast, to the traditional problem of a wind affecting a body with a prescribed magnetic field, we investigate how a non-magnetized wind flow affects a magnetic field that is being self-excited by galactic dynamo action. Methods: To isolate the leading physical effects, we exploit a simple dynamo model that can describe relevant effects. In particular, we use what is known as the "no-z" approximation for the mean-field dynamo equations. Results: In a suitable parametric range we obtain displacements of the large-scale magnetic field, as well as magnetic tails. However, the specific details of their locations are quite counterintuitive. The direction of displacement is perpendicular to, rather than parallel to, the wind direction. The point at which the tail emerges from the galaxy depends on details of the model. The tail is eventually directed downstream. In the simplest case the magnetic tail begins in the region where the wind decreases the total gas velocity. Any wind that penetrates the galaxy modifies the intrinsic dynamo action. These features are different from those found in ram-pressure models. Conclusions: Any determination of galactic motion through the cluster medium from observational data needs to take the effects of dynamo action into account.

  5. An Observational Study of Blended Young Stellar Clusters in the Galactic Plane - Do Massive Stars form First?

    Science.gov (United States)

    Martínez-Galarza, Rafael; Protopapas, Pavlos; Smith, Howard A.; Morales, Esteban

    2018-01-01

    From an observational point of view, the early life of massive stars is difficult to understand partly because star formation occurs in crowded clusters where individual stars often appear blended together in the beams of infrared telescopes. This renders the characterization of the physical properties of young embedded clusters via spectral energy distribution (SED) fitting a challenging task. Of particular relevance for the testing of star formation models is the question of whether the claimed universality of the IMF (references) is reflected in an equally universal integrated galactic initial mass function (IGIMF) of stars. In other words, is the set of all stellar masses in the galaxy sampled from a single universal IMF, or does the distribution of masses depend on the environment, making the IGIMF different from the canonical IMF? If the latter is true, how different are the two? We present a infrared SED analysis of ~70 Spitzer-selected, low mass ($algorithm incorporates a combined probabilistic model of the blended SEDs and the unresolved images in the long-wavelength end. We find that our results are compatible with competitive accretion in the central regions of young clusters, with the most massive stars forming early on in the process and less massive stars forming about 1Myr later. We also find evidence for a relationship between the total stellar mass of the cluster and the mass of the most massive member that favors optimal sampling in the cluster and disfavors random sampling for the canonical IMF, implying that star formation is self-regulated, and that the mass of the most massive star in a cluster depends on the available resources. The method presented here is easily adapted to future observations of clustered regions of star formation with JWST and other high resolution facilities.

  6. Stationary orbits of comets perturbed by Galactic tides

    Science.gov (United States)

    Breiter, S.; Fouchard, M.; Ratajczak, R.

    2008-01-01

    Using the first-order normalized equations describing the heliocentric cometary motion perturbed by the Galactic tides, we identify `stationary solutions' with constant values of the eccentricity, inclination, argument of perihelion and longitude of the ascending node in the reference frame rotating with the Galaxy. The families found involve circular orbits, orbits in the Galactic equatorial plane, rectilinear orbits normal to the equatorial plane, elliptic orbits symmetric with respect to the direction to the Galactic Centre or to its perpendicular, and asymmetrically oriented elliptic orbits. Linear stability of the stationary solution is studied analytically and confirmed by numerical experiments. Most, but not all, of the unstable solutions prove chaotic with the Lyapunov times at least 100Myr.

  7. Evidence for accreted component in the Galactic disks

    Science.gov (United States)

    Xing, Q. F.; Zhao, G.

    2018-02-01

    We analyze the distribution of [Mg/Fe] abundance in the Galactic disks with F- and G-type dwarf stars selected from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) archive. The sample stars are assigned into different stellar populations by using kinematic criteria. Our analysis reveals the chemical inhomogeneities in the Galactic thick disk. A few of metal-poor stars in the thick disk exhibit relatively low [Mg/Fe] abundance in respect to the standard thick-disk sample. The orbital eccentricities and maximum Galactocentric radii of low-α metal-poor stars are apparently greater than that of high-α thick-disk stars. The orbital parameters and chemical components of low-α stars in the thick disk suggests that they may have been formed in regions with low star formation rate that were located at large distances from the Galactic center, such as infalling dwarf spheroidal galaxies.

  8. COBE diffuse infrared background experiment observations of the galactic bulge

    Science.gov (United States)

    Weiland, J. L.; Arendt, R. G.; Berriman, G. B.; Dwek, E.; Freudenreich, H. T.; Hauser, M. G.; Kelsall, T.; Lisse, C. M.; Mitra, M.; Moseley, S. H.

    1994-01-01

    Low angular resolution maps of the Galactic bulge at 1.25, 2.2, 3.5, and 4.9 micrometers obtained by the Diffuse Infrared Background Experiment (DIRBE) onboard NASA's Cosmic Background Explorer (COBE) are presented. After correction for extinction and subtraction of an empirical model for the Galactic disk, the surface brightness distribution of the bulge resembles a flattened ellipse with a minor-to-major axis ratio of approximately 0.6. The bulge minor axis scale height is found to be 2.1 deg +/- 0.2 deg for all four near-infrared wavelengths. Asymmetries in the longitudinal distribution of bulge brightness contours are qualitatively consistent with those expected for a triaxial bar with its near end in the first Galactic quadrant (0 deg less than l less than 90 deg). There is no evidence for an out-of-plane tilt of such a bar.

  9. Some observational aspects of compact galactic X-ray sources

    International Nuclear Information System (INIS)

    Heise, J.

    1982-01-01

    This thesis contains the following observations of compact galactic X-ray sources: i) the X-ray experiments onboard the Astronomical Netherlands Satellite ANS, ii) a rocket-borne ultra soft X-ray experiment and iii) the Objective Grating Spectrometer onboard the EINSTEIN observatory. In Chapter I the various types of compact galactic X-ray sources are reviewed and put into the perspective of earlier and following observations. In Chapter II the author presents some of the observations of high luminosity X-ray sources, made with ANS, including the detection of soft X-rays from the compact X-ray binary Hercules X-1 and the ''return to the high state'' of the black hole candidate Cygnus X-1. Chapter III deals with transient X-ray phenomena. Results on low luminosity galactic X-ray sources are collected in Chapter IV. (Auth.)

  10. Neutrino fluxes from the Galactic plane and the ANTARES limit

    Directory of Open Access Journals (Sweden)

    Fusco Luigi Antonio

    2016-01-01

    Full Text Available The existence of cosmic neutrinos has been reported by the IceCube Collaboration. Though this measurement is consistent with an isotropic neutrino flux, a sub-dominant galactic component coming from extended regions such as the Galactic Plane cannot be excluded. The ANTARES detector, located in the Mediterranean Sea, is currently the largest and longest operated under-water neutrino telescope; its effective area and good exposure to the Southern Sky allow to constrain an enhanced muon neutrino emission from extended sources such as the Galactic Plane. ANTARES data from 2007 to 2013 have been analysed and upper limits on the neutrino production from the central region of our galaxy have been set.

  11. Interpretation of astrophysical neutrinos observed by IceCube experiment by setting Galactic and extra-Galactic spectral components

    Directory of Open Access Journals (Sweden)

    Marinelli Antonio

    2016-01-01

    Full Text Available The last IceCube catalog of High Energy Starting Events (HESE obtained with a livetime of 1347 days comprises 54 neutrino events equally-distributed between the three families with energies between 25 TeV and few PeVs. Considering the homogeneous flavors distribution (1:1:1 and the spectral features of these neutrinos the IceCube collaboration claims the astrophysical origin of these events with more than 5σ. The spatial distribution of cited events does not show a clear correlation with known astrophysical accelerators leaving opened both the Galactic and the extra-Galactic origin interpretations. Here, we compute the neutrino diffuse emission of our Galaxy on the basis of a recently proposed phenomenological model characterized by radially-dependent cosmic-ray (CR transport properties. We show that the astrophysical spectrum measured by IceCube experiment can be well explained adding to the diffuse Galactic neutrino flux (obtained with this new model a extra-Galactic component derived from the astrophysical muonic neutrinos reconstructed in the Northern hemisphere. A good agreement between the expected astrophysical neutrino flux and the IceCube data is found for the full sky as well as for the Galactic plane region.

  12. Creating a career legacy map to help assure meaningful work in nursing.

    Science.gov (United States)

    Hinds, Pamela S; Britton, Dorienda R; Coleman, Lael; Engh, Eileen; Humbel, Tina Kunze; Keller, Susan; Kelly, Katherine Patterson; Menard, Johanna; Lee, Marlene A; Roberts-Turner, Renee; Walczak, Dory

    2015-01-01

    When nurses declare a professional legacy (or what they intend to be better in health care because of their efforts), they are likely to maintain a focus on achieving their legacy and to experience meaning in the process. We depict the legacy and involved steps in creating a legacy map, which is a concrete guide forward to intended career outcomes. Informed by the "meaningful work" literature, we describe a legacy map, its function, the process to create one, and the application of a legacy map to guide careers. We also describe an administrative benefit of the legacy map-the map can be used by team leaders and members to secure needed resources and opportunities to support the desired legacy of team members. Legacy mapping can be a self-use career guidance tool for nurses and other health care professionals or a tool that links the career efforts of a team member with the career support efforts of a team leader. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. WORLD CUP LEGACY AND PERTAINING IMPACTS ON SÃO PAULO CITY´S FUTURE

    Directory of Open Access Journals (Sweden)

    Marcos Vinicius Cardoso

    2013-08-01

    Full Text Available Legacies – structures that are built for events and which remain after the same - are one of the major positive aspects paraded by mega sporting events organizers. This study´s purpose is to analyze the current situation of legacies promised by the many governmental instances for the city of São Paulo - host city of Fifa´s 2014 World Cup – and prospect which legacies will become effective in the city. Preliminary assessments may raise construction concerns, alert the public to keep an eye on undertaken obligations and encourage official actions (Mangan, 2008, p. 1,871. Data was obtained from National Audit Court (TCU reports, Ministry and United Nations documents, in addition to testimonials and information gathered from some of Brazil´s major press media. Data analysis was conducted by classifying legacies according to tangible and intangible legacy concepts (Kaplanidou and Karadakis, 2010 followed by an analysis of promised legacies versus current status during the period of analysis. Finally, discussions as to most probable to come about legacies were presented. Results indicate that a portion of promised legacies stand a fair chance of achievement. On the other hand, other projects lag behind schedule or have been cancelled. Preliminary surveys suggest full completion of promised legacies is not possible, there has been an overuse of public resources as opposed to that planned, and provide indicatives as to the investment´s high opportunity cost.

  14. Orbital Evolution of Planetesimals by the Galactic Tide

    Science.gov (United States)

    Higuchi, A.; Kokubo, E.; Mukai, T.

    2005-05-01

    The Oort cloud is a spherical comet reservoir surrounding the solar system. There is general agreement that the Oort cloud comets are the residual planetesimals of planet formation. The standard scenario of the Oort cloud formation consists of two dynamical stages: (1) giant planets raise the aphelia of planetesimals to the outer region of the solar system and (2) the galactic tide, passing stars, and giant molecular clouds pull up their perihelia out of the planetary region. Here we show the orbital evolution of planetesimals by the galactic tide. Planetesimals with large aphelion distances change their perihelion distances toward the outside of the planetary region by the galactic tide and become members of the Oort cloud. The effect of the galactic tide on the planetesimals with semimajor axes of ˜ 104AU is about 10-3 of the solar gravity. The timescale of the orbital evolution is ˜ 108 years. We consider only the vertical component of the galactic tide. Under the axisymmetric potential, some planetesimals may show the librations around ω (argument of perihelion)=π /2 and 3π /2 (the Kozai mechanism). The alternate increases of eccentricity and inclination of the Kozai mechanism are effective to form the Oort cloud. The secular perturbation theory demonstrates the Kozai mechanism and we can understand the motion of the planetesimals analytically. We apply the Kozai mechanism to the galactic tide and discuss the property of the Oort cloud formed by the Kozai mechanizm. This work was supported by the 21st Century COE Program Origin and Evolution of Planetary Systems of the Ministry of Education, Culture, Sports, Science, and Technology, Japan, and JSPS Research Fellowship for Young Scientists.

  15. GLOBAL SIMULATIONS OF GALACTIC WINDS INCLUDING COSMIC-RAY STREAMING

    Energy Technology Data Exchange (ETDEWEB)

    Ruszkowski, Mateusz [Department of Astronomy, University of Michigan, 1085 S University Avenue, 311 West Hall, Ann Arbor, MI 48109 (United States); Yang, H.-Y. Karen [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Zweibel, Ellen, E-mail: mateuszr@umich.edu, E-mail: hsyang@astro.umd.edu, E-mail: zweibel@astro.wisc.edu [Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706 (United States)

    2017-01-10

    Galactic outflows play an important role in galactic evolution. Despite their importance, a detailed understanding of the physical mechanisms responsible for the driving of these winds is lacking. In an effort to gain more insight into the nature of these flows, we perform global three-dimensional magnetohydrodynamical simulations of an isolated Milky Way-size starburst galaxy. We focus on the dynamical role of cosmic rays (CRs) injected by supernovae, and specifically on the impact of the streaming and anisotropic diffusion of CRs along the magnetic fields. We find that these microphysical effects can have a significant effect on the wind launching and mass loading factors, depending on the details of the plasma physics. Due to the CR streaming instability, CRs propagating in the interstellar medium scatter on self-excited Alfvén waves and couple to the gas. When the wave growth due to the streaming instability is inhibited by some damping process, such as turbulent damping, the coupling of CRs to the gas is weaker and their effective propagation speed faster than the Alfvén speed. Alternatively, CRs could scatter from “extrinsic turbulence” that is driven by another mechanism. We demonstrate that the presence of moderately super-Alfvénic CR streaming enhances the efficiency of galactic wind driving. Cosmic rays stream away from denser regions near the galactic disk along partially ordered magnetic fields and in the process accelerate more tenuous gas away from the galaxy. For CR acceleration efficiencies broadly consistent with the observational constraints, CRs reduce the galactic star formation rates and significantly aid in launching galactic winds.

  16. Global Simulations of Galactic Winds Including Cosmic-ray Streaming

    Science.gov (United States)

    Ruszkowski, Mateusz; Yang, H.-Y. Karen; Zweibel, Ellen

    2017-01-01

    Galactic outflows play an important role in galactic evolution. Despite their importance, a detailed understanding of the physical mechanisms responsible for the driving of these winds is lacking. In an effort to gain more insight into the nature of these flows, we perform global three-dimensional magnetohydrodynamical simulations of an isolated Milky Way-size starburst galaxy. We focus on the dynamical role of cosmic rays (CRs) injected by supernovae, and specifically on the impact of the streaming and anisotropic diffusion of CRs along the magnetic fields. We find that these microphysical effects can have a significant effect on the wind launching and mass loading factors, depending on the details of the plasma physics. Due to the CR streaming instability, CRs propagating in the interstellar medium scatter on self-excited Alfvén waves and couple to the gas. When the wave growth due to the streaming instability is inhibited by some damping process, such as turbulent damping, the coupling of CRs to the gas is weaker and their effective propagation speed faster than the Alfvén speed. Alternatively, CRs could scatter from “extrinsic turbulence” that is driven by another mechanism. We demonstrate that the presence of moderately super-Alfvénic CR streaming enhances the efficiency of galactic wind driving. Cosmic rays stream away from denser regions near the galactic disk along partially ordered magnetic fields and in the process accelerate more tenuous gas away from the galaxy. For CR acceleration efficiencies broadly consistent with the observational constraints, CRs reduce the galactic star formation rates and significantly aid in launching galactic winds.

  17. Chemical evolution coefficients for the study of galactic evolution

    International Nuclear Information System (INIS)

    Mallik, D.C.V.

    1980-01-01

    A new evaluation of chemical evolution coefficients has been made using recent stellar evolution and nucleosynthesis data. The role of the low and intermediate mass stars in galactic nuclosynthesis has been emphasized. A significant amount of 4 He, 12 C and neutron-rich species is found to be contributed by these stars. Comparison with observed abundances suggests a primary origin of 14 N. The simple model of galactic evolution with the new coefficients has been used to derive the ratio of helium to heavy element enrichment in the Galaxy. The new stellar evolution data do not explain the large value of this ratio that has been determined observationally. (orig.)

  18. Crystallography of rare galactic honeycomb structure near supernova 1987a

    Science.gov (United States)

    Noever, David A.

    1994-01-01

    Near supernova 1987a, the rare honeycomb structure of 20-30 galactic bubbles measures 30 x 90 light years. Its remarkable regularity in bubble size suggests a single-event origin which may correlate with the nearby supernova. To test the honeycomb's regularity in shape and size, the formalism of statistical crystallography is developed here for bubble sideness. The standard size-shape relations (Lewis's law, Desch's law, and Aboav-Weaire's law) govern area, perimeter and nearest neighbor shapes. Taken together, they predict a highly non-equilibrium structure for the galactic honeycomb which evolves as a bimodal shape distribution without dominant bubble perimeter energy.

  19. A radio search for planetary nebulae near the galactic center

    International Nuclear Information System (INIS)

    Isaacman, R.B.

    1980-01-01

    Because of galactic center is a hostile environment, and because planetaries are weak radio emitters, it is not clear a priori that one expects to detect any planetary nebulae at all in the nuclear region of the Galaxy. Therefore the expected lifetime and flux density distribution of galactic center nebulae is considered. The principal observational results from the Westerbork data, and the results of some pilot observations with the Very Large Array, which were intended to distinguish planetaries from other radio sources on an individual basis are given. (Auth.)

  20. LOCAL BENCHMARKS FOR THE EVOLUTION OF MAJOR-MERGER GALAXIES-SPITZER OBSERVATIONS OF A K-BAND SELECTED SAMPLE

    International Nuclear Information System (INIS)

    Xu, C. Kevin; Cheng Yiwen; Lu Nanyao; Mazzarella, Joseph M.; Cutri, Roc; Domingue, Donovan; Huang Jiasheng; Gao Yu; Sun, W.-H.; Surace, Jason

    2010-01-01

    We present Spitzer observations for a sample of close major-merger galaxy pairs (KPAIR sample) selected from cross-matches between the Two Micron All Sky Survey and Sloan Digital Sky Survey Data Release 3. The goals are to study the star formation activity in these galaxies and to set a local bench mark for the cosmic evolution of close major mergers. The Spitzer KPAIR sample (27 pairs, 54 galaxies) includes all spectroscopically confirmed spiral-spiral (S+S) and spiral-elliptical (S+E) pairs in a parent sample that is complete for primaries brighter than K = 12.5 mag, projected separations of 5 h -1 kpc ≤ s ≤ 20 h -1 kpc, and mass ratios ≤2.5. The Spitzer data, consisting of images in seven bands (3.6, 4.5, 5.8, 8, 24, 70, 160 μm), show very diversified IR emission properties. Compared to single spiral galaxies in a control sample, only spiral galaxies in S+S pairs show significantly enhanced specific star formation rate (sSFR = SFR/M), whereas spiral galaxies in S+E pairs do not. Furthermore, the SFR enhancement of spiral galaxies in S+S pairs is highly mass-dependent. Only those with M ∼> 10 10.5 M sun show significant enhancement. Relatively low-mass (M ∼ 10 10 M sun ) spirals in S+S pairs have about the same SFR/M compared to their counterparts in the control sample, while those with 10 11 M sun have on average a ∼3 times higher SFR/M than single spirals. There is evidence for a correlation between the global star formation activities (but not the nuclear activities) of the component galaxies in massive S+S major-merger pairs (the H olmberg effect ) . There is no significant difference in the SFR/M between the primaries and the secondaries, nor between spirals of SEP KPAIR =2.54 x 10 -4 (M sun yr -1 Mpc -3 ).