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365 results on '"Thilker D."'

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

Author

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

Published
2017
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102. Effective Radii of Young, Massive Star Clusters in Two LEGUS Galaxies

Author

Ryon, J. E., primary, Gallagher, J. S., additional, Smith, L. J., additional, Adamo, A., additional, Calzetti, D., additional, Bright, S. N., additional, Cignoni, M., additional, Cook, D. O., additional, Dale, D. A., additional, Elmegreen, B. E., additional, Fumagalli, M., additional, Gouliermis, D. A., additional, Grasha, K., additional, Grebel, E. K., additional, Kim, H., additional, Messa, M., additional, Thilker, D., additional, and Ubeda, L., additional

Published
2017
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103. The Hierarchical Distribution of the Young Stellar Clusters in Six Local Star-forming Galaxies

Author

Grasha, K., primary, Calzetti, D., additional, Adamo, A., additional, Kim, H., additional, Elmegreen, B. G., additional, Gouliermis, D. A., additional, Dale, D. A., additional, Fumagalli, M., additional, Grebel, E. K., additional, Johnson, K. E., additional, Kahre, L., additional, Kennicutt, R. C., additional, Messa, M., additional, Pellerin, A., additional, Ryon, J. E., additional, Smith, L. J., additional, Shabani, F., additional, Thilker, D., additional, and Ubeda, L., additional

Published
2017
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104. The properties, origin and evolution of stellar clusters in galaxy simulations and observations

Author

Dobbs, C. L., primary, Adamo, A., additional, Few, C. G., additional, Calzetti, D., additional, Dale, D. A., additional, Elmegreen, B. G., additional, Evans, A. S., additional, Gouliermis, D. A., additional, Grasha, K., additional, Grebel, E. K., additional, Johnson, K. E., additional, Kim, H., additional, Lee, J. C., additional, Messa, M., additional, Ryon, J. E., additional, Smith, L. J., additional, Thilker, D., additional, Ubeda, L., additional, and Whitmore, B., additional

Published
2016
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106. LEGACY EXTRAGALACTIC UV SURVEY (LEGUS) WITH THE HUBBLE SPACE TELESCOPE. I. SURVEY DESCRIPTION

Author

Calzetti, D., Lee, J. C., Sabbi, E., Adamo, Angela, 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, J. S. , I I I, 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, Göran, 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., Calzetti, D., Lee, J. C., Sabbi, E., Adamo, Angela, 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, J. S. , I I I, 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, Göran, 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., and Wofford, A.

Abstract

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 similar to kiloparsec-size clustered structures. Five-band imaging from the nearultraviolet to the I band with the Wide-Field Camera 3 (WFC3), plus parallel optical imaging with the Advanced Camera for Surveys (ACS), is being collected for selected pointings of 50 galaxies within the local 12 Mpc. The filters used for the observations with the WFC3 are F275W(lambda 2704 angstrom), F336W(lambda 3355 angstrom), F438W(lambda 4325 angstrom), F555W(lambda 5308 angstrom), and F814W(lambda 8024 angstrom); the parallel observations with the ACS use the filters F435W (lambda 4328 angstrom), F606W(lambda 5921 angstrom), and F814W(lambda 8057 angstrom). The multiband images are yielding accurate recent (less than or similar to 50 Myr) star formation histories from resolved massive stars and the extinction-corrected ages and masses of star clusters and associations. The extensive inventories of massive stars and clustered systems will be used to investigate the spatial and temporal evolution of star formation within galaxies. This will, in turn, inform theories of galaxy evolution and improve the understanding of the physical underpinning of the gas-star formation relation and the nature of star formation at high redshift. This paper describes the survey, its goals and observational strategy, and the initial scientific results. Because LEGUS will provide a reference survey and a foundation for future observations with the James Webb Space Telescope and with ALMA, a large number of data products are planned for delivery to the community., AuthorCount:48

Published
2015
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107. STAR CLUSTER PROPERTIES in TWO LEGUS GALAXIES COMPUTED with STOCHASTIC STELLAR POPULATION SYNTHESIS MODELS

Author

Krumholz, M, Adamo, A, Fumagalli, M, Wofford, A, Calzetti, D, Lee, J, Whitmore, B, Bright, S, Grasha, K, Gouliermis, D, Kim, H, Nair, P, Ryon, J, Smith, L, Thilker, D, Ubeda, L, Zackrisson, E, Mark R. Krumholz, Angela Adamo, Michele Fumagalli, Aida Wofford, Daniela Calzetti, Janice C. Lee, Bradley C. Whitmore, Stacey N. Bright, Kathryn Grasha, Dimitrios A. Gouliermis, Hwihyun Kim, Preethi Nair, Jenna E. Ryon, Linda J. Smith, David Thilker, Leonardo Ubeda, Erik Zackrisson, Krumholz, M, Adamo, A, Fumagalli, M, Wofford, A, Calzetti, D, Lee, J, Whitmore, B, Bright, S, Grasha, K, Gouliermis, D, Kim, H, Nair, P, Ryon, J, Smith, L, Thilker, D, Ubeda, L, Zackrisson, E, Mark R. Krumholz, Angela Adamo, Michele Fumagalli, Aida Wofford, Daniela Calzetti, Janice C. Lee, Bradley C. Whitmore, Stacey N. Bright, Kathryn Grasha, Dimitrios A. Gouliermis, Hwihyun Kim, Preethi Nair, Jenna E. Ryon, Linda J. Smith, David Thilker, Leonardo Ubeda, and Erik Zackrisson

Abstract

We investigate a novel Bayesian analysis method, based on the Stochastically Lighting Up Galaxies (slug) code, to derive the masses, ages, and extinctions of star clusters from integrated light photometry. Unlike many analysis methods, slug correctly accounts for incomplete initial mass function (IMF) sampling, and returns full posterior probability distributions rather than simply probability maxima. We apply our technique to 621 visually confirmed clusters in two nearby galaxies, NGC 628 and NGC 7793, that are part of the Legacy Extragalactic UV Survey (LEGUS). LEGUS provides Hubble Space Telescope photometry in the NUV, U, B, V, and I bands. We analyze the sensitivity of the derived cluster properties to choices of prior probability distribution, evolutionary tracks, IMF, metallicity, treatment of nebular emission, and extinction curve. We find that slug's results for individual clusters are insensitive to most of these choices, but that the posterior probability distributions we derive are often quite broad, and sometimes multi-peaked and quite sensitive to the choice of priors. In contrast, the properties of the cluster population as a whole are relatively robust against all of these choices. We also compare our results from slug to those derived with a conventional non-stochastic fitting code, Yggdrasil. We show that slug's stochastic models are generally a better fit to the observations than the deterministic ones used by Yggdrasil. However, the overall properties of the cluster populations recovered by both codes are qualitatively similar.

Published
2015

108. THE SPATIAL DISTRIBUTION OF THE YOUNG STELLAR CLUSTERS IN THE STAR-FORMING GALAXY NGC 628

Author

Grasha, K., primary, Calzetti, D., additional, Adamo, A., additional, Kim, H., additional, Elmegreen, B. G., additional, Gouliermis, D. A., additional, Aloisi, A., additional, Bright, S. N., additional, Christian, C., additional, Cignoni, M., additional, Dale, D. A., additional, Dobbs, C., additional, Elmegreen, D. M., additional, Fumagalli, M., additional, III, J. S. Gallagher, additional, Grebel, E. K., additional, Johnson, K. E., additional, Lee, J. C., additional, Messa, M., additional, Smith, L. J., additional, Ryon, J. E., additional, Thilker, D., additional, Ubeda, L., additional, and Wofford, A., additional

Published
2015
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109. The young star cluster population of M51 with LEGUS - I. A comprehensive study of cluster formation and evolution.

Author

Messa, M., Adamo, A., Östlin, G., Calzetti, D., Grasha, K., Grebel, E. K., Shabani, F., Chandar, R., Dale, D. A., Dobbs, C. L., Elmegreen, B. G., Fumagalli, M., Gouliermis, D. A., Kim, H., Smith, L. J., Thilker, D. A., Tosi, M., Ubeda, L., Walterbos, R., and Whitmore, B. C.

Subjects
STAR clusters, STELLAR populations, STELLAR evolution, STAR formation, STELLAR luminosity function, MONTE Carlo method
Abstract

Recently acquired WFC3 UV (F275W and F336W) imaging mosaics under the Legacy Extragalactic UV Survey (LEGUS), combined with archival ACS data of M51, are used to study the young star cluster (YSC) population of this interacting system. Our newly extracted source catalogue contains 2834 cluster candidates, morphologically classified to be compact and uniform in colour, for which ages, masses and extinction are derived. In this first work we study the main properties of the YSC population of the whole galaxy, considering a mass-limited sample. Both luminosity and mass functions follow a power-law shape with slope -2, but at high luminosities and masses a dearth of sources is observed. The analysis of the mass function suggests that it is best fitted by a Schechter function with slope -2 and a truncation mass at 1.00 ± 0.12 × 105 M☉. Through Monte Carlo simulations, we confirm this result and link the shape of the luminosity function to the presence of a truncation in the mass function. A mass limited age function analysis, between 10 and 200 Myr, suggests that the cluster population is undergoing only moderate disruption. We observe little variation in the shape of the mass function at masses above 1 × 104 M☉ over this age range. The fraction of star formation happening in the form of bound clusters in M51 is ~20 per cent in the age range 10-100 Myr and little variation is observed over the whole range from 1 to 200 Myr. [ABSTRACT FROM AUTHOR]

Published
2018
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110. THE BRIGHTEST YOUNG STAR CLUSTERS IN NGC 5253

Author

Calzetti, D., primary, Johnson, K. E., additional, Adamo, A., additional, Gallagher III, J. S., additional, Andrews, J. E., additional, Smith, L. J., additional, Clayton, G. C., additional, Lee, J. C., additional, Sabbi, E., additional, Ubeda, L., additional, Kim, H., additional, Ryon, J. E., additional, Thilker, D., additional, Bright, S. N., additional, Zackrisson, E., additional, Kennicutt, R. C., additional, Mink, S. E. de, additional, Whitmore, B. C., additional, Aloisi, A., additional, Chandar, R., additional, Cignoni, M., additional, Cook, D., additional, Dale, D. A., additional, Elmegreen, B. G., additional, Elmegreen, D. M., additional, Evans, A. S., additional, Fumagalli, M., additional, Gouliermis, D. A., additional, Grasha, K., additional, Grebel, E. K., additional, Krumholz, M. R., additional, Walterbos, R., additional, Wofford, A., additional, Brown, T. M., additional, Christian, C., additional, Dobbs, C., additional, Herrero, A., additional, Kahre, L., additional, Messa, M., additional, Nair, P., additional, Nota, A., additional, Östlin, G., additional, Pellerin, A., additional, Sacchi, E., additional, Schaerer, D., additional, and Tosi, M., additional

Published
2015
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111. LEGACY EXTRAGALACTIC UV SURVEY (LEGUS) WITH THEHUBBLE SPACE TELESCOPE. I. SURVEY DESCRIPTION

Author

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

Published
2015
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112. An Ultraviolet-to-Radio Broadband Spectral Atlas of Nearby Galaxies

Author

Dale, D. A., Gil de Paz, A., Gordon, K. D., Hanson, H. M., Armus, L., Bendo, G. J., Bianchi, L., Block, M., Boissier, S., Boselli, A., Buckalew, B. A., Buat, V., Burgarella, D., Calzetti, D., Cannon, J. M., Engelbracht, C. W., Helou, G., Hollenbach, D. J., Jarrett, T. H., Kennicutt, R. C., Leitherer, C., Li, A., Madore, B. F., Martin, D. C., Meyer, M. J., Murphy, E. J., Regan, M. W., Roussel, H., Smith, J. D. T., Sosey, M. L., Thilker, D. A., and Walter, F.

Subjects
Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

The ultraviolet-to-radio continuum spectral energy distributions are presented for all 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). A principal component analysis of the sample shows that most of the sample's spectral variations stem from two underlying components, one representative of a galaxy with a low infrared-to-ultraviolet ratio and one representative of a galaxy with a high infrared-to-ultraviolet ratio. The influence of several parameters on the infrared-to-ultraviolet ratio is studied (e.g., optical morphology, disk inclination, far-infrared color, ultraviolet spectral slope, and star formation history). Consistent with our understanding of normal star-forming galaxies, the SINGS sample of galaxies in comparison to more actively star-forming galaxies exhibits a larger dispersion in the infrared-to-ultraviolet versus ultraviolet spectral slope correlation. Early-type galaxies, exhibiting low star formation rates and high optical surface brightnesses, have the most discrepant infrared-to-ultraviolet correlation. These results suggest that the star formation history may be the dominant regulator of the broadband spectral variations between galaxies. Finally, a new discovery shows that the 24 μm morphology can be a useful tool for parameterizing the global dust temperature and ultraviolet extinction in nearby galaxies. The dust emission in dwarf/irregular galaxies is clumpy and warm accompanied by low ultraviolet extinction, while in spiral galaxies there is typically a much larger diffuse component of cooler dust and average ultraviolet extinction. For galaxies with nuclear 24 μm emission, the dust temperature and ultraviolet extinction are relatively high compared to disk galaxies.

Published
2007

113. GALEX Ultraviolet photometry of NGC 2420: searching for WDs

Author

Martino, C., Luciana Bianchi, Pagano, I., Herald, J., and Thilker, D.

Subjects
Astrophysics (astro-ph), Astrophysics::Solar and Stellar Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We present color-magnitude diagrams of the open cluster NGC 2420, obtained from Galaxy Evolution Explorer (GALEX) ultraviolet images in FUV and NUV bands and Sloan Digital Sky Survey (SDSS) u,g,r,i,z photometry. Our goal is to search for and characterize hot evolved stars and peculiar objects in this open cluster, as part of a larger project aimed to study a number of open clusters in the Milky Way with GALEX and ground-based data.

Published
2007
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114. NGC 922 - a new drop-through ring galaxy

Author

Wong, O. I., Meurer, G. R., Bekki, K., Hanish, D. J., Kennicutt, R. C., Bland-Hawthorn, J., Ryan-Weber, E. V., Koribalski, B., Kilborn, V. A., Putman, M. E., Heiner, J. S., Webster, R. L., Allen, R. J., Dopita, M. A., Doyle, M. T., Drinkwater, M. J., Ferguson, H. C., Freeman, K. C., Heckman, T. M., Hoopes, C., Knezek, P. M., Meyer, M. J., Oey, M. S., Seibert, M., Smith, R. C., Staveley-Smith, L., Thilker, D., Werk, J., Zwaan, M.A., and Kapteyn Astronomical Institute

Subjects
ULTRAVIOLET, STARBURST GALAXIES, LUMINOSITY, UNIVERSE, Astrophysics::Solar and Stellar Astrophysics, Galaxy : structure, Astrophysics::Cosmology and Extragalactic Astrophysics, DISK GALAXIES, galaxies : individual : NGC 922, CATALOG, LAW, Astrophysics::Galaxy Astrophysics, STAR-FORMATION
Abstract

We have found the peculiar galaxy NGC 922 to be a new drop-through ring galaxy using multiwavelength (ultraviolet-radio) imaging and spectroscopic observations. Its 'C'-shaped morphology and tidal plume indicate a recent strong interaction with its companion which was identified with these observations. Using numerical simulations we demonstrate that the main properties of the system can be generated by a high-speed off-axis drop-through collision of a small galaxy with a larger disc system, thus making NGC 922 one of the nearest known collisional ring galaxies. While these systems are rare in the local Universe, recent deep Hubble Space Telescope images suggest they were more common in the early Universe.

Published
2006

115. UV Morphology and Star Formation in the Tidal Tails of NGC 4038/39

Author

Hibbard, J. E., Bianchi, L., Thilker, D. A., Rich, Robert Michael, Team, The GALEX Science, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)

Subjects
Galaxies: Interactions, Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Ultraviolet: Galaxies, Astrophysics, Galaxies: Intergalactic Medium, Galaxies: Starburst, Galaxies: Individual: NGC Number: NGC 4038, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Galaxies: Individual: NGC Number: NGC 4039, Galaxies: ISM, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We present GALEX FUV (1530 A) and NUV (2310 A) observations of the archetypal merging system NGC 4038/39, ``The Antennae". Both tails are relatively bright in the UV, especially in the vicinity of the Tidal Dwarf Galaxy candidates at the end of the southern tail. The UV light generally falls within the optically delineated tails, although the UV light is considerably more structured, with a remarkably similar morphology to the tidal HI. The UV colors suggest that there has been continuing star formation within the tidal tails, even outside the previously studied Tidal Dwarf regions. Within the inner disk regions, there are interesting UV features which appear to be related to the extended soft X-ray loops and halo recently discovered by CHANDRA., Comment: Uses apjl.cls, emulateapj.sty. 4pgs, 2 figures, 1 table. This paper will be published as part of the Galaxy Evolution Explorer (GALEX) Astrophysical Journal Letters Special Issue. Links to the full set of papers will be available at http:/www.galex.caltech.edu/PUBLICATIONS/ after November 22, 2004. Version with full resolution figures available at http://www.nrao.edu/~jhibbard/n4038/GALEX/

Published
2005

116. Recent star formation in nearby galaxies from GALEX imaging:M101 and M51

Author

Bianchi, Luciana, Thilker, D., Burgarella, D., Friedman, P., Hoopes, C., Boissier, S., de Paz, A. Gil, Barlow, T., Byun, Y. -I., Donas, J., Forster, K., Heckman, T., Jelinsky, P., Lee, Y-W, Madore, B., Malina, R., Martin, C., Milliard, B., Morrissey, P., Neff, S., Rich, M., Schiminovich, D., Siegmund, O., Small, T., Szalay, A., Welsh, B., Wyder, T., Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), California Institute of Technology (CALTECH), Observatories [Carnegie Institution], Carnegie Institution for Science [Washington], Center for Space Astrophysics [Seoul], Yonsei University, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Department of Physics and Astronomy [UCLA Los Angeles], University of California [Los Angeles] (UCLA), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Carnegie Institution for Science, University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)

Subjects
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], galaxies: star clusters, Astrophysics (astro-ph), ultraviolet: galaxies, FOS: Physical sciences, M101), galaxies: individual (M51, Astrophysics
Abstract

The GALEX (Galaxy Evolution Explorer) Nearby Galaxies Survey is providing deep far-UV and near-UV imaging for a representative sample of galaxies in the local universe. We present early results for M51 and M101, from GALEX UV imaging and SDSS optical data in five bands. The multi-band photometry of compact stellar complexes in M101 is compared to population synthesis models, to derive ages, reddening, reddening-corrected luminosities and current/initial masses. The GALEX UV photometry provides a complete census of young compact complexes on a approximately 160pc scale. A galactocentric gradient of the far-UV - near-UV color indicates younger stellar populations towards the outer parts of the galaxy disks, the effect being more pronounced in M101 than in M51., Comment: This paper will be published as part of the Galaxy Evolution Explorer (GALEX) Astrophysical Journal Letters Special Issue. Full paper available from http://dolomiti.pha.jhu.edu . Links to full set of papers will be available at http://www.galex.caltech.edu/PUBLICATIONS/ after November 22, 2004

Published
2005

117. Properties of Extended UV Disk (XUV-disk) Galaxies Discovered by GALEX

Author

A. Thilker, D., Bianchi, L., Meurer, G., Gil de Paz, A., Madore, B., Boissier, Samuel, Ferguson, A., Hameed, S., Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Beaussier, Catherine

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract

2005, AAS, 207, 20202; We have examined a sample of nearby spiral galaxies observed in the UV by GALEX for which Halpha imaging is also available. Our study focused on the radial variation of star formation rate and surface covering factor of UV-bright complexes in the outer galactic disk, in the regime where star formation threshold mechanisms are vitally important. We suggest a classification scheme for identifying extended UV disks (XUV-disks, eg. Thilker et al. and Gil de paz et al.) in our sample, and use this method to constrain salient ensemble characteristics of this galaxy population. Approximately 20-30% of the galaxies in our sample exhibit XUV-disk emission, most frequently in mid-to-early type giant spirals and dwarf Magellanic type galaxies. Some of the XUV disks in our sample appear to have similarly extended Halpha emission originating from sparsely distributed HII regions. We suggest that optically-identified, anti-truncated S0-Sb galaxies may represent the evolved (or presently quiescent) counterparts of the massive XUV-disk population. Finally, we utilize multiwavelength optical imaging in conjunction with our GALEX data for a few XUV-disk galaxies to constrain the stellar mass, bolometric luminosity, and age of individual stellar complexes in the outer disk environment.

Published
2005

118. SYSTEMATIC UNCERTAINTIES ASSOCIATED WITH THE COSMOLOGICAL ANALYSIS OF THE FIRST PAN-STARRS1 TYPE Ia SUPERNOVA SAMPLE

Author

Scolnic, D., primary, Rest, A., additional, Riess, A., additional, Huber, M. E., additional, Foley, R. J., additional, Brout, D., additional, Chornock, R., additional, Narayan, G., additional, Tonry, J. L., additional, Berger, E., additional, Soderberg, A. M., additional, Stubbs, C. W., additional, Kirshner, R. P., additional, Rodney, S., additional, Smartt, S. J., additional, Schlafly, E., additional, Botticella, M. T., additional, Challis, P., additional, Czekala, I., additional, Drout, M., additional, Hudson, M. J., additional, Kotak, R., additional, Leibler, C., additional, Lunnan, R., additional, Marion, G. H., additional, McCrum, M., additional, Milisavljevic, D., additional, Pastorello, A., additional, Sanders, N. E., additional, Smith, K., additional, Stafford, E., additional, Thilker, D., additional, Valenti, S., additional, Wood-Vasey, W. M., additional, Zheng, Z., additional, Burgett, W. S., additional, Chambers, K. C., additional, Denneau, L., additional, Draper, P. W., additional, Flewelling, H., additional, Hodapp, K. W., additional, Kaiser, N., additional, Kudritzki, R.-P., additional, Magnier, E. A., additional, Metcalfe, N., additional, Price, P. A., additional, Sweeney, W., additional, Wainscoat, R., additional, and Waters, C., additional

Published
2014
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119. COSMOLOGICAL CONSTRAINTS FROM MEASUREMENTS OF TYPE Ia SUPERNOVAE DISCOVERED DURING THE FIRST 1.5 yr OF THE Pan-STARRS1 SURVEY

Author

Rest, A., primary, Scolnic, D., additional, Foley, R. J., additional, Huber, M. E., additional, Chornock, R., additional, Narayan, G., additional, Tonry, J. L., additional, Berger, E., additional, Soderberg, A. M., additional, Stubbs, C. W., additional, Riess, A., additional, Kirshner, R. P., additional, Smartt, S. J., additional, Schlafly, E., additional, Rodney, S., additional, Botticella, M. T., additional, Brout, D., additional, Challis, P., additional, Czekala, I., additional, Drout, M., additional, Hudson, M. J., additional, Kotak, R., additional, Leibler, C., additional, Lunnan, R., additional, Marion, G. H., additional, McCrum, M., additional, Milisavljevic, D., additional, Pastorello, A., additional, Sanders, N. E., additional, Smith, K., additional, Stafford, E., additional, Thilker, D., additional, Valenti, S., additional, Wood-Vasey, W. M., additional, Zheng, Z., additional, Burgett, W. S., additional, Chambers, K. C., additional, Denneau, L., additional, Draper, P. W., additional, Flewelling, H., additional, Hodapp, K. W., additional, Kaiser, N., additional, Kudritzki, R.-P., additional, Magnier, E. A., additional, Metcalfe, N., additional, Price, P. A., additional, Sweeney, W., additional, Wainscoat, R., additional, and Waters, C., additional

Published
2014
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120. TheHerschelExploitation of Local Galaxy Andromeda (HELGA)

Author

Viaene, S., primary, Fritz, J., additional, Baes, M., additional, Bendo, G. J., additional, Blommaert, J. A. D. L., additional, Boquien, M., additional, Boselli, A., additional, Ciesla, L., additional, Cortese, L., additional, De Looze, I., additional, Gear, W. K., additional, Gentile, G., additional, Hughes, T. M., additional, Jarrett, T., additional, Karczewski, O. Ł., additional, Smith, M. W. L., additional, Spinoglio, L., additional, Tamm, A., additional, Tempel, E., additional, Thilker, D., additional, and Verstappen, J., additional

Published
2014
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121. The metal-enriched outer disk of NGC2915

Author

Werk, J, Putman, Mary E, Meurer, Gerhardt, Thilker, D. A., Allen, R J, Bland-Hawthorn, Joss, Kravtsov, A, Freeman, Kenneth, Werk, J, Putman, Mary E, Meurer, Gerhardt, Thilker, D. A., Allen, R J, Bland-Hawthorn, Joss, Kravtsov, A, and Freeman, Kenneth

Abstract

We present optical emission-line spectra for outlying H II regions in the extended neutral gas disk surrounding the blue compact dwarf galaxy NGC2915. Using a combination of strong-line R23 and direct oxygen abundance measurements, we report a flat, possibly increasing, metallicity gradient out to 1.2 times the Holmberg radius. We find the outer disk of NGC2915 to be enriched to a metallicity of 0.4 Z. An analysis of the metal yields shows that the outer disk of NGC2915 is overabundant for its gas fraction, while the central star-forming core is similarly underabundant for its gas fraction. Star formation rates derived from very deep 14 ks GALEX FUV exposures indicate that the low level of star formation observed at large radii is not sufficient to have produced the measured oxygen abundances at these galactocentric distances. We consider three plausible mechanisms that may explain the metal-enriched outer gaseous disk of NGC2915: radial redistribution of centrally generated metals, strong galactic winds with subsequent fallback, and galaxy accretion. Our results have implications for the physical origin of the mass-metallicity relation for gas-rich dwarf galaxies.

Published
2010

122. Resolved stellar populations constituting extended UV disks (XUV-disks) in nearby galaxies

Author

Funes, José G., Corsini, Enrico Maria, Thilker, D. A., Bianchi, L., Meurer, G., Gil de Paz, Armando, Boissier, S., Madore, B. F., Ferguson, A., Hameed, S., Neff, S., Martin, C. D., Rich, R. M., Schiminovich, D., Seibert, M.;, M., Wyder, T., Funes, José G., Corsini, Enrico Maria, Thilker, D. A., Bianchi, L., Meurer, G., Gil de Paz, Armando, Boissier, S., Madore, B. F., Ferguson, A., Hameed, S., Neff, S., Martin, C. D., Rich, R. M., Schiminovich, D., Seibert, M.;, M., and Wyder, T.

Abstract

We describe HST imaging of recent star formation complexes located in the extended UV disk (XUV-disk) component of NGC 5236 (M 83), NGC 5055 (M 63), and NGC 2090. Photometry in four FUV-visible bands permits us to constrain the type of resolved stars and effective age of clusters, in addition to extinction. The preliminary results given herein focus on CMD analysis and clustering properties in this unique star-forming environment.

Published
2008

123. TheHerschelExploitation of Local Galaxy Andromeda (HELGA)

Author

Fritz, J., primary, Gentile, G., additional, Smith, M. W. L., additional, Gear, W. K., additional, Braun, R., additional, Roman Duval, J., additional, Bendo, G. J., additional, Baes, M., additional, Eales, S. A., additional, Verstappen, J., additional, Blommaert, J. A. D. L., additional, Boquien, M., additional, Boselli, A., additional, Clements, D., additional, Cooray, A. R., additional, Cortese, L., additional, De Looze, I., additional, Ford, G. P., additional, Galliano, F., additional, Gomez, H. L., additional, Gordon, K. D., additional, Lebouteiller, V., additional, O’Halloran, B., additional, Kirk, J., additional, Madden, S. C., additional, Page, M. J., additional, Remy, A., additional, Roussel, H., additional, Spinoglio, L., additional, Thilker, D., additional, Vaccari, M., additional, Wilson, C. D., additional, and Waelkens, C., additional

Published
2012
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124. THEHERSCHELEXPLOITATION OF LOCAL GALAXY ANDROMEDA (HELGA). II. DUST AND GAS IN ANDROMEDA

Author

Smith, M. W. L., primary, Eales, S. A., additional, Gomez, H. L., additional, Roman-Duval, J., additional, Fritz, J., additional, Braun, R., additional, Baes, M., additional, Bendo, G. J., additional, Blommaert, J. A. D. L., additional, Boquien, M., additional, Boselli, A., additional, Clements, D. L., additional, Cooray, A. R., additional, Cortese, L., additional, de Looze, I., additional, Ford, G. P., additional, Gear, W. K., additional, Gentile, G., additional, Gordon, K. D., additional, Kirk, J., additional, Lebouteiller, V., additional, Madden, S., additional, Mentuch, E., additional, O’Halloran, B., additional, Page, M. J., additional, Schulz, B., additional, Spinoglio, L., additional, Verstappen, J., additional, Wilson, C. D., additional, and Thilker, D. A., additional

Published
2012
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126. THE METAL-ENRICHED OUTER DISK OF NGC 2915

Author

Werk, J. K., primary, Putman, M. E., additional, Meurer, G. R., additional, Thilker, D. A., additional, Allen, R. J., additional, Bland-Hawthorn, J., additional, Kravtsov, A., additional, and Freeman, K., additional

Published
2010
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128. OUTLYING H II REGIONS IN H I-SELECTED GALAXIES

Author

Werk, J. K., primary, Putman, M. E., additional, Meurer, G. R., additional, Ryan-Weber, E. V., additional, Kehrig, C., additional, Thilker, D. A., additional, Bland-Hawthorn, J., additional, Drinkwater, M. J., additional, Kennicutt, R. C., additional, Wong, O. I., additional, Freeman, K. C., additional, Oey, M. S., additional, Dopita, M. A., additional, Doyle, M. T., additional, Ferguson, H. C., additional, Hanish, D. J., additional, Heckman, T. M., additional, Kilborn, V. A., additional, Kim, J. H., additional, Knezek, P. M., additional, Koribalski, B., additional, Meyer, M., additional, Smith, R. C., additional, and Zwaan, M. A., additional

Published
2009
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130. EVIDENCE FOR A NONUNIFORM INITIAL MASS FUNCTION IN THE LOCAL UNIVERSE

Author

Meurer, Gerhardt R., primary, Wong, O. I., additional, Kim, J. H., additional, Hanish, D. J., additional, Heckman, T. M., additional, Werk, J., additional, Bland-Hawthorn, J., additional, Dopita, M. A., additional, Zwaan, M. A., additional, Koribalski, B., additional, Seibert, M., additional, Thilker, D. A., additional, Ferguson, H. C., additional, Webster, R. L., additional, Putman, M. E., additional, Knezek, P. M., additional, Doyle, M. T., additional, Drinkwater, M. J., additional, Hoopes, C. G., additional, Kilborn, V. A., additional, Meyer, M., additional, Ryan-Weber, E. V., additional, Smith, R. C., additional, and Staveley-Smith, L., additional

Published
2009
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132. Erratum: “An Ultraviolet‐to‐Radio Broadband Spectral Atlas of Nearby Galaxies” (ApJ, 655, 863 [2007])

Author

Dale, D. A., primary, Gil de Paz, A., additional, Gordon, K. D., additional, Hanson, H. M., additional, Armus, L., additional, Bendo, G. J., additional, Bianchi, L., additional, Block, M., additional, Boissier, S., additional, Boselli, A., additional, Buckalew, B. A., additional, Buat, V., additional, Burgarella, D., additional, Calzetti, D., additional, Cannon, J. M., additional, Engelbracht, C. W., additional, Helou, G., additional, Hollenbach, D. J., additional, Jarrett, T. H., additional, Kennicutt, R. C., additional, Leitherer, C., additional, Li, A., additional, Madore, B. F., additional, Meyer, M. J., additional, Murphy, E. J., additional, Regan, M. W., additional, Roussel, H., additional, Smith, J. D. T., additional, Sosey, M. L., additional, Thilker, D. A., additional, and Walter, F., additional

Published
2008
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133. The Survey for Ionization in Neutral Gas Galaxies. III. Diffuse, Warm Ionized Medium and Escape of Ionizing Radiation

Author

Oey, M. S., primary, Meurer, G. R., additional, Yelda, S., additional, Furst, E. J., additional, Caballero‐Nieves, S. M., additional, Hanish, D. J., additional, Levesque, E. M., additional, Thilker, D. A., additional, Walth, G. L., additional, Bland‐Hawthorn, J., additional, Dopita, M. A., additional, Ferguson, H. C., additional, Heckman, T. M., additional, Doyle, M. T., additional, Drinkwater, M. J., additional, Freeman, K. C., additional, Kennicutt, Jr., R. C., additional, Kilborn, V. A., additional, Knezek, P. M., additional, Koribalski, B., additional, Meyer, M., additional, Putman, M. E., additional, Ryan‐Weber, E. V., additional, Smith, R. C., additional, Staveley‐Smith, L., additional, Webster, R. L., additional, Werk, J., additional, and Zwaan, M. A., additional

Published
2007
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134. An Ultraviolet‐to‐Radio Broadband Spectral Atlas of Nearby Galaxies

Author

Dale, D. A., primary, de Paz, A. Gil, additional, Gordon, K. D., additional, Hanson, H. M., additional, Armus, L., additional, Bendo, G. J., additional, Bianchi, L., additional, Block, M., additional, Boissier, S., additional, Boselli, A., additional, Buckalew, B. A., additional, Buat, V., additional, Burgarella, D., additional, Calzetti, D., additional, Cannon, J. M., additional, Engelbracht, C. W., additional, Helou, G., additional, Hollenbach, D. J., additional, Jarrett, T. H., additional, Kennicutt, R. C., additional, Leitherer, C., additional, Li, A., additional, Madore, B. F., additional, Martin, D. C., additional, Meyer, M. J., additional, Murphy, E. J., additional, Regan, M. W., additional, Roussel, H., additional, Smith, J. D. T., additional, Sosey, M. L., additional, Thilker, D. A., additional, and Walter, F., additional

Published
2007
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135. Erratum: "Dusty Waves on a Starry Sea: The Mid-Infrared View of M31" ([URL ADDRESS="/cgi-bin/resolve?2006ApJ...650L..45B" STATUS="OKAY"]ApJ 650, L45 [2006][/URL])

Author

Barmby, P., primary, Ashby, M. L. N., additional, Bianchi, L., additional, Engelbracht, C. W., additional, Gehrz, R. D., additional, Gordon, K. D., additional, Hinz, J. L., additional, Huchra, J. P., additional, Humphreys, R. M., additional, Pahre, M. A., additional, Pérez-González, P. G., additional, Polomski, E. F., additional, Rieke, G. H., additional, Thilker, D. A., additional, Willner, S. P., additional, and Woodward, C. E., additional

Published
2007
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136. Dusty Waves on a Starry Sea: The Mid-Infrared View of M31

Author

Barmby, P., primary, Ashby, M. L. N., additional, Bianchi, L., additional, Engelbracht, C. W., additional, Gehrz, R. D., additional, Gordon, K. D., additional, Hinz, J. L., additional, Huchra, J. P., additional, Humphreys, R. M., additional, Pahre, M. A., additional, Pérez-González, P. G., additional, Polomski, E. F., additional, Rieke, G. H., additional, Thilker, D. A., additional, Willner, S. P., additional, and Woodward, C. E., additional

Published
2006
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137. Sp i t zer MIPS Infrared Imaging of M31: Further Evidence for a Spiral-Ring Composite Structure

Author

Gordon, K. D., primary, Bailin, J., additional, Engelbracht, C. W., additional, Rieke, G. H., additional, Misselt, K. A., additional, Latter, W. B., additional, Young, E. T., additional, Ashby, M. L. N., additional, Barmby, P., additional, Gibson, B. K., additional, Hines, D. C., additional, Hinz, J., additional, Krause, O., additional, Levine, D. A., additional, Marleau, F. R., additional, Noriega-Crespo, A., additional, Stolovy, S., additional, Thilker, D. A., additional, and Werner, M. W., additional

Published
2006
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138. Star Formation in NGC 5194 (M51a): The Panchromatic View fromGALEXtoSpitzer

Author

Calzetti, D., primary, Kennicutt, Jr., R. C., additional, Bianchi, L., additional, Thilker, D. A., additional, Dale, D. A., additional, Engelbracht, C. W., additional, Leitherer, C., additional, Meyer, M. J., additional, Sosey, M. L., additional, Mutchler, M., additional, Regan, M. W., additional, Thornley, M. D., additional, Armus, L., additional, Bendo, G. J., additional, Boissier, S., additional, Boselli, A., additional, Draine, B. T., additional, Gordon, K. D., additional, Helou, G., additional, Hollenbach, D. J., additional, Kewley, L., additional, Madore, B. F., additional, Martin, D. C., additional, Murphy, E. J., additional, Rieke, G. H., additional, Rieke, M. J., additional, Roussel, H., additional, Sheth, K., additional, Smith, J. D., additional, Walter, F., additional, White, B. A., additional, Yi, S., additional, Scoville, N. Z., additional, Polletta, M., additional, and Lindler, D., additional

Published
2005
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141. Ultraviolet Emission from Stellar Populations within Tidal Tails: Catching the Youngest Galaxies in Formation?

Author

Neff, S. G., primary, Thilker, D. A., additional, Seibert, M., additional, de Paz, A. Gil, additional, Bianchi, L., additional, Schiminovich, D., additional, Martin, D. C., additional, Madore, B. F., additional, Rich, R. M., additional, Barlow, T. A., additional, Byun, Y.-I., additional, Donas, J., additional, Forster, K., additional, Friedman, P. G., additional, Heckman, T. M., additional, Jelinsky, P. N., additional, Lee, Y.-W., additional, Malina, R. F., additional, Milliard, B., additional, Morrissey, P., additional, Siegmund, O. H. W., additional, Small, T., additional, Szalay, A. S., additional, Welsh, B. Y., additional, and Wyder, T. K., additional

Published
2005
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144. Westerbork H I observations of high-velocity clouds near M 31and M 33

Author

Westmeier, T., Braun, R., Thilker, D., Westmeier, T., Braun, R., and Thilker, D.

Abstract

We have undertaken high-resolution follow-up of a sample of high velocity $\ion{H}{i}$clouds apparently associated with M 31. Our sample was chosen from the population of high-velocity clouds (HVCs) detected out to 50 kpc projected radius of the Andromeda Galaxy by Thilker et al. (2004, ApJ, 601, L39) with the Green Bank Telescope. Nine pointings were observed with the Westerbork Synthesis Radio Telescope to determine the physical parameters of these objects and to find clues to their origin. One additional pointing was directed at a similar object near M 33.
At $2'$resolution we detect 16 individual HVCs around M 31and 1 HVC near M 33with typical $\ion{H}{i}$masses of a few times $10^5 \, M_{\odot}$and sizes of the order of 1 kpc. Estimates of the dynamical and virial masses of some of the HVCs indicate that they are likely gravitationally dominated by additional mass components such as dark matter or ionised gas. Twelve of the clouds are concentrated in an area of only $1^{\circ} \times 1^{\circ}$at a projected separation of less than 15 kpc from the disk of M 31. This HVC complex has a rather complicated morphological and kinematical structure and partly overlaps with the giant stellar stream of M 31, suggesting a tidal origin. Another detected feature is in close proximity, in both position and velocity, with NGC 205, perhaps also indicative of tidal processes. Other HVCs in our survey are isolated and might represent primordial, dark-matter dominated clouds.

Published
2005
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147. Cosmological Constraints from Measurements of Type Ia Supernovae Discovered during the First 1.5 yr of the Pan-STARRS1 Survey

Author

Rest, Armin Wolfgang, Scolnic, D., Foley, R. J., Huber, M. E., Chornock, R., Narayan, Gautham Siddharth, Tonry, J. L., Berger, Edo, Soderberg, Alicia M., Stubbs, Christopher William, Riess, A., Kirshner, Robert P., Smartt, S. J., Schlafly, E., Rodney, S., Botticella, M. T., Brout, D., Challis, P., Czekala, Ian Philip, Drout, Maria Rebecca, Hudson, M. J., Kotak, R., Leibler, C., Lunnan, Ragnhild, Marion, G. H., McCrum, M., Milisavljevic, D., Pastorello, A., Sanders, Nathan Edward, Smith, K., Stafford, E., Thilker, D., Valenti, S., Wood-Vasey, W. M., Zheng, Z., Burgett, W. S., Chambers, K. C., Denneau, L., Draper, P. W., Flewelling, H., Hodapp, K. W., Kaiser, N., Kudritzki, R.-P., Magnier, E. A., Metcalfe, N., Price, P. A., Sweeney, W., Wainscoat, R., and Waters, C.

Subjects
cosmological parameters, cosmology: observations, dark energy, supernovae: general
Abstract

We present griz P1 light curves of 146 spectroscopically confirmed Type Ia supernovae (SNe Ia; 0.03 < z < 0.65) discovered during the first 1.5 yr of the Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is determined by a combination of on-site measurements of the instrument response function and observations of spectrophotometric standard stars. We find that the systematic uncertainties in the photometric system are currently 1.2% without accounting for the uncertainty in the Hubble Space Telescope Calspec definition of the AB system. A Hubble diagram is constructed with a subset of 113 out of 146 SNe Ia that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113 PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only supernovae (SNe) and assuming a constant dark energy equation of state and flatness, yields $w=-1.120^{+0.360}_{-0.206}\hbox{(Stat)} ^{+0.269}_{-0.291}\hbox{(Sys)}$. When combined with BAO+CMB(Planck)+H 0, the analysis yields $\Omega _{\rm M}=0.280^{+0.013}_{-0.012}$ and $w=-1.166^{+0.072}_{-0.069}$ including all identified systematics. The value of w is inconsistent with the cosmological constant value of –1 at the 2.3σ level. Tension endures after removing either the baryon acoustic oscillation (BAO) or the H 0 constraint, though it is strongest when including the H 0 constraint. If we include WMAP9 cosmic microwave background (CMB) constraints instead of those from Planck, we find $w=-1.124^{+0.083}_{-0.065}$, which diminishes the discord to <2σ. We cannot conclude whether the tension with flat ΛCDM is a feature of dark energy, new physics, or a combination of chance and systematic errors. The full Pan-STARRS1 SN sample with ~three times as many SNe should provide more conclusive results., Astronomy

Published
2014
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148. Systematic Uncertainties Associated with the Cosmological Analysis of the First Pan-STARRS1 Type Ia Supernova Sample

Author

Scolnic, D., Rest, A., Riess, A., Huber, M. E., Foley, R. J., Brout, D., Chornock, R., Narayan, G., Tonry, J. L., Berger, Edo, Soderberg, Alicia M., Stubbs, Christopher William, Kirshner, Robert P., Rodney, S., Smartt, S. J., Schlafly, E., Botticella, M. T., Challis, P., Czekala, I., Drout, M., Hudson, M. J., Kotak, R., Leibler, C., Lunnan, R., Marion, G. H., McCrum, M., Milisavljevic, Danny, Pastorello, A., Sanders, Nathan Edward, Smith, K., Stafford, E., Thilker, D., Valenti, S., Wood-Vasey, W. M., Zheng, Z., Burgett, W. S., Chambers, K. C., Denneau, L., Draper, P. W., Flewelling, H., Hodapp, K. W., Kaiser, N., Kudritzki, R.-P., Magnier, E. A., Metcalfe, N., Price, P. A., Sweeney, W., Wainscoat, R., and Waters, C.

Subjects
supernova general, cosmology observations, cosmological parameters
Abstract

We probe the systematic uncertainties from the 113 Type Ia supernovae (SN Ia) in the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of low-redshift surveys. The companion paper by Rest et al. (2013) describes the photometric measurements and cosmological inferences from the PS1 sample. The largest systematic uncertainty stems from the photometric calibration of the PS1 and low-z samples. We increase the sample of observed Calspec standards from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II calibration systems are compared and discrepancies up to ∼ 0.02 mag are recovered. We find uncertainties in the proper way to treat intrinsic colors and reddening produce differences in the recovered value of w up to 3%. We estimate masses of host galaxies of PS1 supernovae and detect an insignificant difference in distance residuals of the full sample of 0.037±0.031 mag for host galaxies with high and low masses. Assuming flatness and including systematic uncertainties in our analysis of only SNe measurements, we find w =−1.120+0.360 −0.206(Stat)+0.269 −0.291(Sys). With additional constraints from BAO, CMB (Planck) and H0 measurements, we find w = −1.166+0.072 −0.069 and Ωm = 0.280+0.013 −0.012 (statistical and systematic errors added in quadrature). Significance of the inconsistency with w = −1 depends on whether we use Planck or WMAP measurements of the CMB: wBAO+H0+SN+WMAP = −1.124+0.083−0.065., Astronomy

Published
2014
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149. Discovery, photometry, and astrometry of 49?classical nova candidates in M?81?galaxy

Author

Hornoch, K., Scheirich, P., Garnavich, P., Hameed, S., and Thilker, D.

Abstract

Aims. This paper reports on a search for new classical nova candidates in the M?81 galaxy based on archival, as well as recent, new images.Methods. We used images from 1999?2007 to search for optical transients in M?81. The positions of the identified classical nova candidates were used to study their spatial distribution. Kolmogorov-Smirnov test (KS) and bottom-to-top (BTR) ratio diagnostic were used to analyze the nova candidate distribution and differentiate between the disk and the bulge populations.Results. In total, 49?classical nova candidates were discovered. In this study, we present the precise positions and photometry of these objects, plus the photometry of an additional 9?classical nova candidates found by Neill & Shara (2004, AJ, 127, 816). With our large sample, we find a different spatial distribution of classical nova candidates when compared to the results of earlier studies. Also, an extraordinarily bright nova was found and studied in detail.

Published
2008

150. Mid-infrared Observations Of M31

Author

Pauline Barmby, Ashby, M. L., Pahre, M. A., Willner, S. P., Huchra, J. P., Gehrz, R. D., Polomski, E. F., Woodward, C. E., Humphreys, R. M., Gordon, K. D., Hinz, J. L., Engelbracht, C. W., Perez-Gonzalez, P. G., Rieke, G. H., Bianchi, L., and Thilker, D. H.

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