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1. Legacy ExtraGalactic UV Survey with The Hubble Space Telescope. Stellar cluster catalogues and first insights into cluster formation and evolution in NGC 628

Author

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., Ostlin, G., Pellerin, A., Prieto, J., Regan, M. W., Sabbi, E., Sacchi, E., Schaerer, D., Shabani, D. Schiminovich F., Tosi, M., Van Dyk, S. D., and Zackrisson, E.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We report the large effort which is producing comprehensive high-level young star cluster (YSC) catalogues 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 NGC628 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 NGC628 is consistent with a power-law distribution of slopes $\sim -2$ and a truncation of a few times $10^5$ M$_\odot$. After their formation YSCs and compact associations follow different evolutionary paths. YSCs survive for a longer timeframe, confirming their being potentially bound systems. Associations disappear on time scales comparable to hierarchically organized star-forming regions, suggesting that they are expanding systems. We find mass-independent cluster disruption in the inner region of NGC628, while in the outer part of the galaxy there is little or no disruption. We observe faster disruption rates for low mass ($\leq$ $10^4$ M$_\odot$) clusters suggesting that a mass-dependent component is necessary to fully describe the YSC disruption process in NGC628., Comment: accepted for publication in ApJ; 27 pages; complete stellar cluster catalogues will be released in June 2017 at https://legus.stsci.edu

Published
2017
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2. Star cluster catalogues for the LEGUS dwarf galaxies

Author

D O Cook, J C Lee, A Adamo, H Kim, R Chandar, B C Whitmore, A Mok, J E Ryon, D A Dale, D Calzetti, J E Andrews, A Aloisi, G Ashworth, S N Bright, T M Brown, C Christian, M Cignoni, G C Clayton, R da Silva, S E de Mink, C L Dobbs, B G Elmegreen, D M Elmegreen, A S Evans, M Fumagalli, J S Gallagher, D A Gouliermis, K Grasha, E K Grebel, A Herrero, D A Hunter, E I Jensen, K E Johnson, L Kahre, R C Kennicutt, M R Krumholz, N J Lee, D Lennon, S Linden, C Martin, M Messa, P Nair, A Nota, G Östlin, R C Parziale, A Pellerin, M W Regan, E Sabbi, E Sacchi, D Schaerer, D Schiminovich, F Shabani, F A Slane, J Small, C L Smith, L J Smith, S Taibi, D A Thilker, I C de la Torre, M Tosi, J A Turner, L Ubeda, S D Van Dyk, R AM Walterbos, and A Wofford

Published
2019
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3. The Resolved Stellar Populations in the LEGUS Galaxies1

Author

D. M. Elmegreen, Elena Sabbi, A. Dolphin, Geoffrey C. Clayton, Eva K. Grebel, Linda J. Smith, T. M. Brown, G. Ashworth, R. Walterbos, Matteo Messa, Lauren Kahre, J. Prieto, Alessandra Aloisi, Rupali Chandar, C. D. Martin, Mark R. Krumholz, M. W. Regan, Daniel A. Dale, Bruce G. Elmegreen, Hwihyun Kim, Kathryn Grasha, Elena Sacchi, F. Shabani, A. Herrero, R. C. Kennicutt, David O. Cook, J. E. Ryon, A. Nota, B. C. Whitmore, L. Ubeda, D. Schaerer, D. Schiminovich, Jennifer E. Andrews, J. C. Lee, Stacey N. Bright, Dimitrios A. Gouliermis, John S. Gallagher, D. J. Lennon, Michele Fumagalli, Daniela Calzetti, Kelsey E. Johnson, Michele Cignoni, S. D. Van Dyk, C. Christian, P. Nair, Clare Dobbs, Aaron S. Evans, Monica Tosi, G. Ostlin, Anne Pellerin, Deidre A. Hunter, David A. Thilker, Angela Adamo, S. E. de Mink, Aida Wofford, Sabbi, E, Calzetti, D, Ubeda, L, Adamo, A, Cignoni, M, Thilker, D, Aloisi, A, Elmegreen, B, Elmegreen, D, Gouliermis, D, Grebel, E, Messa, M, Smith, L, Tosi, M, Dolphin, A, Andrews, J, Ashworth, G, Bright, S, Brown, T, Chandar, R, Christian, C, Clayton, G, Cook, D, Dale, D, De Mink, S, Dobbs, C, Evans, A, Fumagalli, M, Gallagher, J, Grasha, K, Herrero, A, Hunter, D, Johnson, K, Kahre, L, Kennicutt, R, Kim, H, Krumholz, M, Lee, J, Lennon, D, Martin, C, Nair, P, Nota, A, Ostlin, G, Pellerin, A, Prieto, J, Regan, M, Ryon, J, Sacchi, E, Schaerer, D, Schiminovich, D, Shabani, F, Van Dyk, S, Walterbos, R, Whitmore, B, Wofford, A, Sabbi, E [0000-0003-2954-7643], Calzetti, D [0000-0002-5189-8004], Adamo, A [0000-0002-8192-8091], Cignoni, M [0000-0001-6291-6813], Thilker, D [0000-0002-8528-7340], Aloisi, A [0000-0003-4137-882X], Elmegreen, BG [0000-0002-1723-6330], Elmegreen, DM [0000-0002-1392-3520], Gouliermis, DA [0000-0002-2763-0075], Grebel, EK [0000-0002-1891-3794], Smith, LJ [0000-0002-0806-168X], Tosi, M [0000-0002-0986-4759], Dolphin, A [0000-0001-8416-4093], Chandar, R [0000-0003-0085-4623], Clayton, GC [0000-0002-0141-7436], Dale, DA [0000-0002-5782-9093], Grasha, K [0000-0002-3247-5321], Hunter, DA [0000-0002-3322-9798], Johnson, KE [0000-0001-8348-2671], Kahre, L [0000-0002-2037-3096], Pellerin, A [0000-0003-1887-1966], Prieto, J [0000-0003-0943-0026], Sacchi, E [0000-0001-5618-0109], Schaerer, D [0000-0001-7144-7182], Shabani, F [0000-0002-5266-1260], Walterbos, R [0000-0002-0782-3064], Apollo - University of Cambridge Repository, and Low Energy Astrophysics (API, FNWI)

Subjects
Hertzsprung–Russell diagram, Russell and C-M diagram, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Advanced Camera for Surveys, symbols.namesake, galaxies: star clusters: general, galaxies: star formation, galaxies: stellar content, Hertzsprung, Russell and C-M diagrams, stars: formation, Astronomy and Astrophysics, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, Star formation, Galaxy, Red-giant branch, Stars, Star cluster, symbols, Hertzsprung-Russell and C-M diagrams, Astrophysics::Earth and Planetary Astrophysics, Wide Field Camera 3
Abstract

The Legacy ExtraGalactic UV Survey (LEGUS) is a multiwavelength Cycle 21 Treasury program on the Hubble Space Telescope. It studied 50 nearby star-forming galaxies in 5 bands from the near-UV to the I-band, combining new Wide Field Camera 3 observations with archival Advanced Camera for Surveys data. LEGUS was designed to investigate how star formation occurs and develops on both small and large scales, and how it relates to the galactic environments. In this paper we present the photometric catalogs for all the apparently single stars identified in the 50 LEGUS galaxies. Photometric catalogs and mosaicked images for all filters are available for download. We present optical and near-UV color-magnitude diagrams for all the galaxies. For each galaxy we derived the distance from the tip of the red giant branch. We then used the NUV color-magnitude diagrams to identify stars more massive than 14 M ☉, and compared their number with the number of massive stars expected from the GALEX FUV luminosity. Our analysis shows that the fraction of massive stars forming in star clusters and stellar associations is about constant with the star formation rate. This lack of a relation suggests that the timescale for evaporation of unbound structures is comparable or longer than 10 Myr. At low star formation rates this translates to an excess of mass in clustered environments as compared to model predictions of cluster evolution, suggesting that a significant fraction of stars form in unbound systems. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA Inc., under NASA contract NAS 5-26555.

Published
2018

4. Legacy extraGalactic UV survey with the Hubble space telescope : stellar cluster catalogs and first insights into cluster formation and evolution in NGC 628

Author

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

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Photometry (optics), galaxies: individual (NGC 628, M74), Hubble space telescope, 0103 physical sciences, Cluster (physics), Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Luminosity function (astronomy), Physics, Spiral galaxy, stars: formation, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, galaxies: star clusters: general, galaxies: star formation, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), galaxies: individual (NGC 628, Spectral energy distribution, Low Mass, M74)
Abstract

We report the large effort which is producing comprehensive high-level young star cluster (YSC) catalogues 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 NGC628 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 NGC628 is consistent with a power-law distribution of slopes $\sim -2$ and a truncation of a few times $10^5$ M$_\odot$. After their formation YSCs and compact associations follow different evolutionary paths. YSCs survive for a longer timeframe, confirming their being potentially bound systems. Associations disappear on time scales comparable to hierarchically organized star-forming regions, suggesting that they are expanding systems. We find mass-independent cluster disruption in the inner region of NGC628, while in the outer part of the galaxy there is little or no disruption. We observe faster disruption rates for low mass ($\leq$ $10^4$ M$_\odot$) clusters suggesting that a mass-dependent component is necessary to fully describe the YSC disruption process in NGC628., accepted for publication in ApJ; 27 pages; complete stellar cluster catalogues will be released in June 2017 at https://legus.stsci.edu

Published
2017

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

Author

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

Subjects
Astrofísica, Galaxies: Interactions, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy merger, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Galaxies: Evolution, 0103 physical sciences, Galaxies: Individual: NGC Number: NGC 7771, Astrophysics::Solar and Stellar Astrophysics, Angstrom, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Dwarf galaxy, Physics, 010308 nuclear & particles physics, Star formation, Galaxies: Individual: NGC Number: NGC 520, Astrophysics (astro-ph), Galaxies: Individual: NGC Number: NGC 5719, Astronomy and Astrophysics, Galaxy, Astronomía, Stars, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Galaxies: Individual: Name: Arp 295
Abstract

New GALEX observations have detected significant FUV (1530 Angstroms) and NUV (2310 Angstroms) emission from stellar substructures within the tidal tails of four ongoing galaxy mergers. The UV-bright regions are optically faint and are coincident with HI density enhancements. FUV emission is detected at any location where the HI surface density exceeds ~2 M_sun pc^{-2}, and is often detected in the absence of visible wavelength emission. UV luminosities of the brighter regions of the tidal tails imply masses of 10^6 M_sun to ~10^9 M_sun in young stars in the tails, and HI luminosities imply similar HI masses. UV-optical colors of the tidal tails indicate stellar populations as young as a few Myr, and in all cases ages < 400Myr. Most of the young stars in the tails formed in single bursts rather than resulting from continuous star formation, and they formed *in situ* as the tails evolved. Star formation appears to be older near the parent galaxies and younger at increasing distances from the parent galaxy. This could be because the star formation occurs progressively along the tails, or because the star formation has been inhibited near the galaxy/tail interface. The youngest stellar concentrations, usually near the ends of long tidal tails, have masses comparable to confirmed tidal dwarf galaxies and may be newly forming galaxies undergoing their first burst of star formation., 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

Published
2005
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6. 'Cosmic Windows' Sky Surveys

Author

Huub Röttgering, T. M. Heckman, C. J. Lonsdale, J. J. Condon, Q. F. Yin, Seb Oliver, Helen Smith, C. D. Martin, D. Schiminovich, and W. D. Cotton

Subjects
Physics, COSMIC cancer database, media_common.quotation_subject, Astronomy, Astrophysics, Spectral line, Redshift, Galaxy, law.invention, Telescope, Interstellar medium, law, Sky, Cirrus, media_common
Abstract

Far-infrared (FIR), ultraviolet (UV), and soft X-ray observations are easily degraded by dust and gas between the source and the telescope. They must be made from space, where they are still affected by the interstellar medium (ISM) of our Galaxy. Fortunately the ISM is quite patchy, with several “cosmic windows” covering ∼ 100 deg2 of sky having exceptionally low interstellar extinction and cirrus emission. Since the universe is nearly isotropic, these windows contain representative samples of cosmologically distant sources and will be the targets of deep multiwavelength studies including SWIRE, GALEX/DIS, and XMM-LSS. Overlapping optical and radio surveys provide essential source identifications, redshifts, morphologies, and continuum spectra. The prototype VLA survey (see http://www.cv.nrao.edu/sirtf_fls/) covers the 5 deg2 SIRTF First-Look Survey (FLS) and is being used to identify the expected FIR sources in advance. Most will be star-forming galaxies obeying the very tight far-infrared/radio correlation and thus continuum radio sources stronger than S ≈ 100 μJy at 1.4 GHz. Proposed VLA surveys covering the remaining “cosmic windows” will be useful for studying the evolution of obscured AGNs, clusters, and other uncommon objects.

Published
2005
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7. A new noise source in superconducting tunnel junction photon detectors

Author

Kenneth Segall, Christopher Wilson, Liang Li, D. Schiminovich, Benjamin A. Mazin, Christopher Martin, Luigi Frunzio, Daniel E. Prober, and R. Vasquez

Subjects
Physics, Photon, Condensed matter physics, business.industry, Shot noise, Photodetector, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Condensed Matter Physics, Noise (electronics), Electronic, Optical and Magnetic Materials, Condensed Matter::Superconductivity, Quasiparticle, Optoelectronics, Superconducting tunnel junction, Quantum efficiency, Electrical and Electronic Engineering, business, Quantum tunnelling
Abstract

We report on the development of an "all-in-one" detector that provides spectroscopy, imaging, photon timing, and high quantum efficiency with single photon sensitivity: the optical/UV single-photon imaging spectrometer using superconducting tunnel junctions. Our devices utilize a lateral trapping geometry. Photons are absorbed in a Ta thin film, creating excess quasiparticles. Quasiparticles diffuse and are trapped by Al/AlO/sub x//Al tunnel junctions located on the sides of the absorber. Imaging devices have tunnel junctions on two opposite sides of the absorber. Position information is obtained from the fraction of the total charge collected by each junction. We have measured the single photon response of our devices. For photon energies between 2 eV and 5 eV we measure an energy resolution between 0.47 eV and 0.40 eV respectively on a selected region of the absorber. We see evidence that thermodynamic fluctuations of the number of thermal quasiparticles in the junction electrodes leads to current noise that far exceeds the expected shot noise of the dc bias current. We believe that this may limit the resolution of our present generation of detectors at the operating temperature of 0.22 K.

Published
2001
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8. The First Release COSMOS Optical and Near-IR Data and Catalog

Author

P. Capak, H. Aussel, M. Ajiki, H. J. McCracken, B. Mobasher, N. Scoville, P. Shopbell, Y. Taniguchi, D. Thompson, S. Tribiano, S. Sasaki, A. W. Blain, M. Brusa, C. Carilli, A. Comastri, C. M. Carollo, P. Cassata, J. Colbert, R. S. Ellis, M. Elvis, M. Giavalisco, W. Green, L. Guzzo, G. Hasinger, O. Ilbert, C. Impey, K. Jahnke, J. Kartaltepe, J.‐P. Kneib, J. Koda, A. Koekemoer, Y. Komiyama, A. Leauthaud, O. Lefevre, S. Lilly, C. Liu, R. Massey, S. Miyazaki, T. Murayama, T. Nagao, J. A. Peacock, A. Pickles, C. Porciani, A. Renzini, J. Rhodes, M. Rich, M. Salvato, D. B. Sanders, C. Scarlata, D. Schiminovich, E. Schinnerer, M. Scodeggio, K. Sheth, Y. Shioya, L. A. M. Tasca, J. E. Taylor, L. Yan, G. Zamorani, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), P. Capak, H. Aussel, M. Ajiki, H. J. McCracken, B. Mobasher, N. Scoville, P. Shopbell, Y. Taniguchi, D. Thompson, S. Tribiano, S. Sasaki, A. W. Blain, M. Brusa, C. Carilli, A. Comastri, C. M. Carollo, P. Cassata, J. Colbert, R. S. Elli, M. Elvi, M. Giavalisco, W. Green, L. Guzzo, G. Hasinger, O. Ilbert, C. Impey, K. Jahnke, J. Kartaltepe, J. Kneib, J. Koda, A. Koekemoer, Y. Komiyama, A. Leauthaud, O. L. Fevre, S. Lilly, C. Liu, R. Massey, S. Miyazaki, T. Murayama, T. Nagao, J. A. Peacock, A. Pickle, C. Porciani, A. Renzini, J. Rhode, M. Rich, M. Salvato, D. B. Sander, C. Scarlata, D. Schiminovich, E. Schinnerer, M. Scodeggio, K. Sheth, Y. Shioya, L. A. M., J. E. Taylor, L. Yan, and G. Zamorani

Subjects
Population, Large-scale structure of universe, FOS: Physical sciences, Field of view, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Surveys, 01 natural sciences, Imaging data, Cosmology: Observations, Spectral line, law.invention, Photometry (optics), Telescope, law, 0103 physical sciences, Galaxies: Evolution, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, education.field_of_study, 010308 nuclear & particles physics, Astrophysics (astro-ph), Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Galaxy, Panchromatic film, Cosmology: Large-Scale Structure of Universe, Cosmology: Observation, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Cosmology: observations, Galaxies: evolution, Astrophysics::Earth and Planetary Astrophysics
Abstract

We present imaging data and photometry for the COSMOS survey in 15 photometric bands between 0.3um and 2.4um. These include data taken on the Subaru 8.3m telescope, the KPNO and CTIO 4m telescopes, and the CFHT 3.6m telescope. Special techniques are used to ensure that the relative photometric calibration is better than 1% across the field of view. The absolute photometric accuracy from standard star measurements is found to be 6%. The absolute calibration is corrected using galaxy spectra, providing colors accurate to 2% or better. Stellar and galaxy colors and counts agree well with the expected values. Finally, as the first step in the scientific analysis of these data we construct panchromatic number counts which confirm that both the geometry of the universe and the galaxy population are evolving., Comment: 19 pages, 13 figures, 14 tables, Accepted to ApJS for COSMOS speciall issue

Published
2007
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9. The Optical Spectra of 24 ?m Galaxies in the COSMOS Field. I. Spitzer MIPS Bright Sources in the zCOSMOS-Bright 10k Catalog

Author

K. I. Caputi, S. J. Lilly, H. Aussel, D. Sanders, D. Frayer, O. Le Fèvre, A. Renzini, G. Zamorani, M. Scodeggio, T. Contini, N. Scoville, C. M. Carollo, G. Hasinger, A. Iovino, V. Le Brun, E. Le Floc’h, C. Maier, V. Mainieri, M. Mignoli, M. Salvato, D. Schiminovich, J. Silverman, J. Surace, L. Tasca, U. Abbas, S. Bardelli, M. Bolzonella, A. Bongiorno, D. Bottini, P. Capak, A. Cappi, P. Cassata, A. Cimatti, O. Cucciati, S. de la Torre, L. de Ravel, P. Franzetti, M. Fumana, B. Garilli, C. Halliday, O. Ilbert, P. Kampczyk, J. Kartaltepe, J.‐P. Kneib, C. Knobel, K. Kovac, F. Lamareille, A. Leauthaud, J. F. Le Borgne, D. Maccagni, C. Marinoni, H. McCracken, B. Meneux, P. Oesch, R. Pellò, E. Pérez‐Montero, C. Porciani, E. Ricciardelli, R. Scaramella, C. Scarlata, L. Tresse, D. Vergani, J. Walcher, M. Zamojski, E. Zucca, 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), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH), AUTRES, Università di Bologna, Dipartimento di Astronomia, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), INAF - Osservatorio Astronomico di Bologna (OABO), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Brera (OAB), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institute of Liver Studies, King's College Hospital (KCH), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Active galactic nucleus, Field (physics), Metallicity, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Galaxies: Abundances, 0103 physical sciences, Galaxies: Evolution, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, Star formation, Astrophysics (astro-ph), Spectral properties, Astronomy and Astrophysics, Galaxies: Active, Redshift, Optical spectra, Galaxy, Infrared: Galaxies, Space and Planetary Science, Galaxies: abundances, Galaxies: active, Galaxies: evolution, Infrared: galaxies
Abstract

We study zCOSMOS-bright optical spectra for 609 Spitzer/MIPS 24 micron-selected galaxies with S(24um)> 0.30 mJy and I10^11 Lsun galaxies at 0.6, Comment: Accepted for publication at the ApJ. 35 pages including 24 figures. Updated to match version in press

Published
2008
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10. zCOSMOS: A Large VLT/VIMOS redshift survey covering 0 < z < 3 in the COSMOS field

Author

S. J. Lilly, O. Le Fevre, A. Renzini, G. Zamorani, M. Scodeggio, T. Contini, C. M. Carollo, G. Hasinger, J.‐P. Kneib, A. Iovino, V. Le Brun, C. Maier, V. Mainieri, M. Mignoli, J. Silverman, L. A. M. Tasca, M. Bolzonella, A. Bongiorno, D. Bottini, P. Capak, K. Caputi, A. Cimatti, O. Cucciati, E. Daddi, R. Feldmann, P. Franzetti, B. Garilli, L. Guzzo, O. Ilbert, P. Kampczyk, K, Kovac, F. Lamareille, A. Leauthaud, J.‐F. Le Borgne, H. J. McCracken, C. Marinoni, R. Pello, E. Ricciardelli, C. Scarlata, D. Vergani, D. B. Sanders, E. Schinnerer, N. Scoville, Y. Taniguchi, S. Arnouts, H. Aussel, S. Bardelli, M. Brusa, A. Cappi, P. Ciliegi, A. Finoguenov, S. Foucaud, R. Franceschini, C. Halliday, C. Impey, C. Knobel, A. Koekemoer, J. Kurk, D. Maccagni, S. Maddox, B. Marano, G. Marconi, B. Meneux, B. Mobasher, C. Moreau, J. A. Peacock, C. Porciani, L. Pozzetti, R. Scaramella, D. Schiminovich, P. Shopbell, I. Smail, D. Thompson, L. Tresse, G. Vettolani, A. Zanichelli, E. Zucca, 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), 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), Institute for Astronomy, Department of Physics, ETH Zürich, Università degli Studi di Padova = University of Padua (Unipd), INAF-Osservatorio Astronomico di Bologna (OABO), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Milano), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Extraterrestriche Physik (MPE), INAF-Osservatorio Astronomico di Brera, Cahill Center for Astronomy and Astrophysics, California Institute of Technology, INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA), National Optical Astronomy Observatory, Tucson (NOAO), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Institute for Astronomy, University of Hawaii, Max-Planck-Institut für Astronomie (MPIA), Tohoku University, Nottingham University, University of Arizona (UoA), Space Telescope Science Institute (STScI), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), European Southern Observatory (ESO), University of Edinburgh, Istituto Nazionale di Astrofisica (INAF), Columbia University, New York, Institute for Computational Cosmology, Department of Physics, Durham University, Durham (ICC), IRA-INAF, Bologna, Beaussier, Catherine, Lilly S. J., Le Fèvre O., Renzini A., Zamorani G., Scodeggio M., Contini T., Carollo C. M., Hasinger G., Kneib J.-P., Iovino A., Le Brun V., Maier C., Mainieri V., Mignoli M., Silverman J., Tasca L. A. M., Bolzonella M., Bongiorno A., Bottini D., Capak P., Caputi K., Cimatti A., Cucciati O., Daddi E., Feldmann R., Franzetti P., Garilli B., Guzzo L., Ilbert O., Kampczyk P., Kovac K., Lamareille F., Leauthaud A., Borgne J.-F. Le, McCracken H. J., Marinoni C., Pello R., Ricciardelli E., Scarlata C., Vergani D., Sanders D. B., Schinnerer E., Scoville N., Taniguchi Y., Arnouts S., Aussel H., Bardelli S., Brusa M., Cappi A., Ciliegi P., Finoguenov A., Foucaud S., Franceschini R., Halliday C., Impey C., Knobel C., Koekemoer A., Kurk J., Maccagni D., Maddox S., Marano B., Marconi G., Meneux B., Mobasher B., Moreau C., Peacock J. A., Porciani C., Pozzetti L., Scaramella R., Schiminovich D., Shopbell P., Smail I., Thompson D., Tresse L., Vettolani G., Zanichelli A., and Zucca E.

Subjects
Physics, Active galactic nucleus, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics, Redshift survey, 01 natural sciences, Redshift, Spectral line, Galaxy, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Space and Planetary Science, Galaxy group, 0103 physical sciences, Emission spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Spectrograph
Abstract

zCOSMOS is a large redshift survey that is being undertaken in the COSMOS field using 600 hours of observation with the VIMOS spectrograph on the 8-m VLT. The survey is designed to characterise the environments of COSMOS galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCOSMOS survey consists of two parts: (a) zCOSMOS-bright, a magnitude-limited I-band IAB < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg2 COSMOS ACS field and designed to mimic the parameters of the 2dfGRS; and (b) zCOSMOS-deep, a survey of approximately 10,000 galaxies selected through colour-selection criteria to have 1.4 < z < 3.0, within the central 1 deg2. This paper describes the survey design and the construction of the target catalogues, and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCOSMOS-bright targets and of 977 zCOSMOS-deep targets have been obtained. These are briefly analysed to demonstrate the characteristics that may be expected from zCOSMOS, and particularly zCOSMOS-bright, when it is finally completed between 2008-2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. Our zCOSMOS-deep spectra demonstrate the effectiveness of our selection techniques to isolate high redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines., Comment: 24 pages plus 16 figures. Accepted, to appear in the ApJ Supplement COSMOS Special Issue

Published
2006
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11. Star formation in the nearby universe: the ultraviolet and infrared points of view

Author

J. Iglesias‐Paramo, V. Buat, T. T. Takeuchi, K. Xu, S. Boissier, A. Boselli, D. Burgarella, B. F. Madore, A. Gil de Paz, L. Bianchi, T. A. Barlow, Y.‐I. Byun, J. Donas, K. Forster, P. G. Friedman, T. M. Heckman, P. N. Jelinski, Y.‐W. Lee, R. F. Malina, D. C. Martin, B. Milliard, P. F. Morrissey, S. G. Neff, R. M. Rich, D. Schiminovich, M. Seibert, O. H. W. Siegmund, T. Small, A. S. Szalay, B. Y. Welsh, T. K. Wyder, 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 Beaussier, Catherine

Subjects
Astrofísica, 010504 meteorology & atmospheric sciences, Infrared, FOS: Physical sciences, Astrophysics, Lambda, medicine.disease_cause, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, medicine, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, COSMIC cancer database, Star formation, Astrophysics (astro-ph), Estimator, Astronomy and Astrophysics, Galaxy, Astronomía, Wavelength, 13. Climate action, Space and Planetary Science, [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Ultraviolet
Abstract

This work presents the main ultraviolet (UV) and far-infrared (FIR) properties of two samples of nearby galaxies selected from the GALEX ($\lambda = 2315$\AA, hereafter NUV) and IRAS ($\lambda = 60\mu$m) surveys respectively. They are built in order to get detection at both wavelengths for most of the galaxies. Star formation rate (SFR) estimators based on the UV and FIR emissions are compared. Systematic differences are found between the SFR estimators for individual galaxies based on the NUV fluxes corrected for dust attenuation and on the total IR luminosity. A combined estimator based on NUV and IR luminosities seems to be the best proxy over the whole range of values of SFR. Although both samples present similar average values of the birthrate parameter b, their star-formation-related properties are substantially different: NUV-selected galaxies tend to show larger values of $b$ for lower masses, SFRs and dust attenuations, supporting previous scenarios for the star formation history (SFH). Conversely, about 20% of the FIR-selected galaxies show high values of $b$, SFR and NUV attenuation. These galaxies, most of them being LIRGs and ULIRGs, break down the downsizing picture for the SFH, however their relative contribution per unit volume is small in the local Universe. Finally, the cosmic SFR density of the local Universe is estimated in a consistent way from the NUV and IR luminosities., Comment: 43 pages, 13 figures, accepted for publication in Astrophysical Journal Supplement Series

Published
2006

12. COSMOS : Hubble Space Telescope Observations

Author

N. Scoville, R. G. Abraham, H. Aussel, J. E. Barnes, A. Benson, A. W. Blain, D. Calzetti, A. Comastri, P. Capak, C. Carilli, J. E. Carlstrom, C. M. Carollo, J. Colbert, E. Daddi, R. S. Ellis, M. Elvis, S. P. Ewald, M. Fall, A. Franceschini, M. Giavalisco, W. Green, R. E. Griffiths, L. Guzzo, G. Hasinger, C. Impey, J.‐P. Kneib, J. Koda, A. Koekemoer, O. Lefevre, S. Lilly, C. T. Liu, H. J. McCracken, R. Massey, Y. Mellier, S. Miyazaki, B. Mobasher, J. Mould, C. Norman, A. Refregier, A. Renzini, J. Rhodes, M. Rich, D. B. Sanders, D. Schiminovich, E. Schinnerer, M. Scodeggio, K. Sheth, P. L. Shopbell, Y. Taniguchi, N. D. Tyson, C. M. Urry, L. Van Waerbeke, P. Vettolani, S. D. M. White, L. Yan, 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), Institut d'Astrophysique de Paris (IAP), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Dark matter, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Surveys, Cosmology: Observations, 7. Clean energy, 01 natural sciences, Advanced Camera for Surveys, Physical cosmology, Hubble space telescope, Galaxies: Evolution, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Weak gravitational lensing, Physics, Pixel, 010308 nuclear & particles physics, Cosmology: Dark Matter, Galaxies: Formation, Astrophysics (astro-ph), Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Galaxy, Cosmology: Large-Scale Structure of Universe, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Limiting magnitude, Astrophysics::Earth and Planetary Astrophysics
Abstract

The Cosmic Evolution Survey (COSMOS) was initiated with an extensive allocation (590 orbits in Cycles 12-13) using the Hubble Space Telescope (HST) for high resolution imaging. Here we review the characteristics of the HST imaging with the Advanced Camera for Surveys (ACS) and parallel observations with NICMOS and WFPC2. A square field (1.8$\sq$\deg) has been imaged with single-orbit ACS I-F814W exposures with 50% completeness for sources 0.5\arcsec in diameter at I$_{AB} $ = 26.0 mag. The ACS imaging is a key part of the COSMOS survey, providing very high sensitivity and high resolution (0.09\arcsec FWHM, 0.05\arcsec pixels) imaging and detecting 1.2 million objects to a limiting magnitude of 26.5 (AB). These images yield resolved morphologies for several hundred thousand galaxies. The small HST PSF also provides greatly enhanced sensitivity for weak lensing investigations of the dark matter distribution., Comment: 21 pages, 6 figures -- to appear in COSMOS ApJ Suppl. special issue

Published
2006
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13. The GALEX VIMOS-VLT Deep Survey Measurement of the Evolution of the 1500 Å Luminosity Function

Author

S. Arnouts, D. Schiminovich, O. Ilbert, L. Tresse, B. Milliard, M. Treyer, S. Bardelli, T. Budavari, T. K. Wyder, E. Zucca, O. Le Fèvre, D. C. Martin, G. Vettolani, C. Adami, M. Arnaboldi, T. Barlow, L. Bianchi, M. Bolzonella, D. Bottini, Y.-I. Byun, A. Cappi, S. Charlot, T. Contini, J. Donas, K. Forster, S. Foucaud, P. Franzetti, P. G. Friedman, B. Garilli, I. Gavignaud, L. Guzzo, T. M. Heckman, C. Hoopes, A. Iovino, P. Jelinsky, V. Le Brun, Y.-W. Lee, D. Maccagni, B. F. Madore, R. Malina, B. Marano, C. Marinoni, H. J. McCracken, A. Mazure, B. Meneux, R. Merighi, P. Morrissey, S. Neff, S. Paltani, R. Pellò, J. P. Picat, A. Pollo, L. Pozzetti, M. Radovich, R. M. Rich, R. Scaramella, M. Scodeggio, M. Seibert, O. Siegmund, T. Small, A. S. Szalay, B. Welsh, C. K. Xu, G. Zamorani, A. Zanichelli, 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), Schiminovich D., Ilbert O., Arnouts S., Milliard B., Tresse L., Le Fèvre O., Treyer M., Wyder T. K., Budavári T., Zucca E., Zamorani G., Martin D. C., Adami C., Arnaboldi M., Bardelli S., Barlow T., Bianchi L., Bolzonella M., Bottini D., Byun Y.I., Cappi A., Contini T., Charlot S., Donas J., Forster K., Foucaud S., Franzetti P., Friedman P. G., Garilli B., Gavignaud I., Guzzo L., Heckman T. M., Hoopes C., Iovino A., Jelinsky P., Le Brun V., Lee Y.W., Maccagni D., Madore B. F., Malina R., Marano B., Marinoni C., McCracken H. J., Mazure A., Meneux B., Morrissey P., Neff S., Paltani S., Pellò R., Picat J. P., Pollo A., Pozzetti L., Radovich M., Rich R. M., Scaramella R., Scodeggio M., Seibert M., Siegmund O., Small T., Szalay A. S., Vettolani G., Welsh B., Xu C. K., Zanichelli A., 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
Physics, GALAXIES: MASS FUNCTION, Number density, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Star formation, media_common.quotation_subject, Galaxies: Luminosity Function, Astronomy and Astrophysics, Astrophysics, Ultraviolet: Galaxies, 01 natural sciences, Cosmology: Observations, Redshift, Universe, Galaxy, Luminosity, Mass Function, Space and Planetary Science, 0103 physical sciences, Galaxies: Evolution, 010303 astronomy & astrophysics, Luminosity function (astronomy), media_common
Abstract

We present the first measurement of the galaxy luminosity function (LF) at 1500 Å in the range 0.2=alpha>=-1.65, with a marginally significant hint of increase at higher z. (3) We split the sample in three rest-frame (B-I) intervals, providing an approximate spectral type classification: Sb-Sd, Sd-Irr, and unobscured starbursts. We find that the bluest class evolves less strongly in luminosity than the two other classes. On the other hand, their number density increases sharply with z (~15% in the local universe to ~55% at z~1), while that of the reddest classes decreases.

Published
2005
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14. The GALEX-VVDS Measurement of the Evolution of the Far-Ultraviolet Luminosity Density and the Cosmic Star Formation Rate

Author

D. Schiminovich, O. Ilbert, S. Arnouts, B. Milliard, L. Tresse, O. Le Fèvre, M. Treyer, T. K. Wyder, T. Budavári, E. Zucca, G. Zamorani, D. C. Martin, C. Adami, M. Arnaboldi, S. Bardelli, T. Barlow, L. Bianchi, M. Bolzonella, D. Bottini, Y.-I. Byun, A. Cappi, T. Contini, S. Charlot, J. Donas, K. Forster, S. Foucaud, P. Franzetti, P. G. Friedman, B. Garilli, I. Gavignaud, L. Guzzo, T. M. Heckman, C. Hoopes, A. Iovino, P. Jelinsky, V. Le Brun, Y.-W. Lee, D. Maccagni, B. F. Madore, R. Malina, B. Marano, C. Marinoni, H. J. McCracken, A. Mazure, B. Meneux, P. Morrissey, S. Neff, S. Paltani, R. Pellò, J. P. Picat, A. Pollo, L. Pozzetti, M. Radovich, R. M. Rich, R. Scaramella, M. Scodeggio, M. Seibert, O. Siegmund, T. Small, A. S. Szalay, G. Vettolani, B. Welsh, C. K. Xu, A. Zanichelli, 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), Schiminovich D., Ilbert O., Arnouts S., Milliard B., Tresse L., Le Fèvre O., Treyer M., Wyder T. K., Budavári T., Zucca E., Zamorani G., Martin D. C., Adami C., Arnaboldi M., Bardelli S., Barlow T., Bianchi L., Bolzonella M., Bottini D., Byun Y.I., Cappi A., Contini T., Charlot S., Donas J., Forster K., Foucaud S., Franzetti P., Friedman P. G., Garilli B., Gavignaud I., Guzzo L., Heckman T. M., Hoopes C., Iovino A., Jelinsky P., Le Brun V., Lee Y.W., Maccagni D., Madore B. F., Malina R., Marano B., Marinoni C., McCracken H. J., Mazure A., Meneux B., Morrissey P., Neff S., Paltani S., Pellò R., Picat J. P., Pollo A., Pozzetti L., Radovich M., Rich R. M., Scaramella R., Scodeggio M., Seibert M., Siegmund O., Small T., Szalay A. S., Vettolani G., Welsh B., Xu C. K., Zanichelli A., 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: MASS FUNCTION, Galaxies: Luminosity Function, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Ultraviolet: Galaxies, medicine.disease_cause, 01 natural sciences, Cosmology: Observations, Luminosity, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Galaxies: Evolution, medicine, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Luminosity function (astronomy), Physics, COSMIC cancer database, 010308 nuclear & particles physics, Star formation, Attenuation, Astrophysics (astro-ph), Astronomy and Astrophysics, Redshift, Galaxy, Mass Function, Space and Planetary Science, Ultraviolet
Abstract

In a companion paper (Arnouts et al. 2004) we presented new measurements of the galaxy luminosity function at 1500 Angstroms out to z~1 using GALEX-VVDS observations (1039 galaxies with NUV0.2) and at higher z using existing data sets. In this paper we use the same sample to study evolution of the FUV luminosity density. We detect evolution consistent with a (1+z)^{2.5+/-0.7} rise to z~1 and (1+z)^{0.5+/-0.4} for z>1. The luminosity density from the most UV-luminous galaxies (UVLG) is undergoing dramatic evolution (x30) between 025%) of the total FUV luminosity density at z, Comment: 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

Published
2005
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15. Neutral hydrogen associated with shells and other fine structure in NGC 2865: A dynamically young elliptical?

Author

Jm Vanderhulst, D Schiminovich, Df Malin, and Jh Vangorkom

Subjects
Physics, Solar mass, Mass distribution, Centaurus A, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Interstellar medium, Dark matter halo, Stars, Space and Planetary Science, Elliptical galaxy, Astrophysics::Galaxy Astrophysics
Abstract

We report the discovery of neutral hydrogen in a second elliptical galaxy with shells, NGC 2865. Very Large Array (VLA) images reveal an association between the neutral hydrogen (H I) and the fine structure (shells, tails, and loops) in the galaxy. Similar to what we previously observed in NGC 5128 (Centaurus A), most of the 6 x 10(exp 8)/h(exp 2) solar mass of cold gas is found in a broken ring in the outer regions of NGC 2865 (beyond 0.5D(sub 25)) and is displaced to the outside of the shells and loops. The measured velocities cover a range of 500 km/s around the systematic velocity. The velocity field of the outer H I has the same sense and magnitude (and line of nodes) as that of the stars in the elliptical body. Although NGC 2865 appears to be a relaxed elliptical galaxy, deep images, photometry, and spectroscopy suggest that the galaxy might be the recent (less than 7 Gyr) product of a major disk-disk merger -- a 'dynamically young elliptical.' Our H I data support this hypothesis. Nevertheless, the association between gas and stellar fine structure, with gas displaced outward from the stars in projected position, implies gas motions not predicted by any of the current merger scenarios. Using the H I ring and assuming nearly circular motion, we measure M/L(sub B) at large radii (4 x 0.5D(sub 25)). We find M/L(sub B) = 33 +/- 4 h, a factor of 5 greater than the value of M/L(sub B) found for the central regions, indicating the presence of a dark halo.

Published
1995
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16. Discovery of Neutral Hydrogen Associated with the Diffuse Shells of NGC 5128 (Centaurus A)

Author

Jm Vanderhulst, Jh Vangorkom, D Schiminovich, S Kasow, and Kapteyn Astronomical Institute

Subjects
DYNAMICS, GALAXIES, ELLIPTIC AND LENTICULAR, CD, Hydrogen, Radio galaxy, Centaurus A, POTENTIALS, chemistry.chemical_element, RADIO GALAXIES, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, CORONAE, Curvature, ELLIPTICAL GALAXIES, FILAMENTS, Ionization, STELLAR SHELLS, GALAXIES, INDIVIDUAL (NGC 5128), GALAXIES, JETS, Astrophysics::Galaxy Astrophysics, NGC-5128, Physics, GALAXIES, STRUCTURE, GALAXIES, INTERACTIONS, Astronomy, Astronomy and Astrophysics, Galaxy, Dust lane, CONTINUUM, chemistry, Space and Planetary Science, Elliptical galaxy
Abstract

In this Letter, we present for the first time images and kinematics of neutral hydrogen, which is unambiguously associated with the optical shells of an E/SO galaxy, NGC 5128. Using the VLA, we have mapped diffuse H I (21 cm) emission out to approximately 15 kpc (15') from the nucleus of the galaxy to a limiting column density of 10(20) cm-2. These observations reveal the presence of 1.5 x 10(8) M. of H I, 10'-15' NE, N, and SW of the galaxy. The H I distribution follows the curvature of the outermost ''diffuse'' shells, and is slightly displaced, shifted 1' to the outside of the shells. The H I shows a smooth gradient in velocity over approximately 450 km s-1, nearly the same line-of-sight velocity range observed in the dust lane. Our results suggest that the H I might be a partial ring, rotating with the same sense as the main body of the galaxy. We discuss merger, accretion, and internal shell formation models and describe how the observed properties of the H I challenge existing theories of shell formation. We also find a morphological and kinematical connection between the NE cloud of H I and the outer optical filaments of Cen A, identifying the H I as the source of gas being ionized. Finally, we discuss the implications of these results on the study of high-z radio galaxies with extended emission-line regions.

Published
1994
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17. GALEX DETECTION OF SHOCK BREAKOUT IN TYPE IIP SUPERNOVA PS1-13arp: IMPLICATIONS FOR THE PROGENITOR STAR WIND.

Author

S. Gezari, D. O. Jones, N. E. Sanders, A. M. Soderberg, T. Hung, S. Heinis, S. J. Smartt, A. Rest, D. Scolnic, R. Chornock, E. Berger, R. J. Foley, M. E. Huber, P. Price, C. W. Stubbs, A. G. Riess, R. P. Kirshner, K. Smith, W. M. Wood-Vasey, and D. Schiminovich

Subjects
SUPERNOVAE, STARBURSTS, STARS, STELLAR luminosity function, LUMINOSITY
Abstract

We present the GALEX detection of a UV burst at the time of explosion of an optically normal supernova (SN) IIP (PS1-13arp) from the Pan-STARRS1 survey at z = 0.1665. The temperature and luminosity of the UV burst match the theoretical predictions for shock breakout in a red supergiant (RSG), but with a duration a factor of ∼50 longer than expected. We compare the NUV light curve of PS1-13arp to previous GALEX detections of SNe IIP and find clear distinctions that indicate that the UV emission is powered by shock breakout, and not by the subsequent cooling envelope emission previously detected in these systems. We interpret the ∼1 day duration of the UV signal with a shock breakout in the wind of an RSG with a pre-explosion mass-loss rate of yr−1. This mass-loss rate is enough to prolong the duration of the shock breakout signal, but not enough to produce an excess in the optical plateau light curve or narrow emission lines powered by circumstellar interaction. This detection of non-standard, potentially episodic high mass loss in an RSG SN progenitor has favorable consequences for the prospects of future wide-field UV surveys to detect shock breakout directly in these systems, and provide a sensitive probe of the pre-explosion conditions of SN progenitors. [ABSTRACT FROM AUTHOR]

Published
2015
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18. Photometric redshift and classification for the XMM-COSMOS sources

Author

M. Mignoli, J. Silvermann, Jeyhan S. Kartaltepe, A. Rau, A. Buongiorno, Mara Salvato, M. Bolzonella, David Schiminovich, Roberto Gilli, H. J. McCracken, Knud Jahnke, G. Zamorani, Patrick J. McCarthy, R. Cook, Y. Shioya, Stephane Arnouts, Nico Cappelluti, Yoshiaki Taniguchi, Karina Caputi, M. Zamojski, Peter Capak, D. B. Sanders, Jonathan R. Trump, Chris Impey, E. Le Floc'h, G. Hasinger, Vernesa Smolčić, T. Murayama, Nick Scoville, F. Lamareille, S. J. Lilly, Francesca Civano, O. Ilbert, Jason Surace, Bahram Mobasher, Martin Elvis, David R. Thompson, Meg Urry, Marcella Brusa, H. Aussel, S. S. Sasaki, Patrick L. Shopbell, Vincenzo Mainieri, 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), M. Salvato, G. Hasinger, O. Ilbert, G. Zamorani, M. Brusa, N. Z. Scoville, A. Rau, P. Capak, S. Arnout, H. Aussel, M. Bolzonella, A. Buongiorno, N. Cappelluti, K. Caputi, F. Civano, R. Cook, M. Elvi, R. Gilli, K. Jahnke, J. S. Kartaltepe, C. D. Impey, F. Lamareille, E. L. Floc'h, S. Lilly, V. Mainieri, P. McCarthy, H. McCracken, M. Mignoli, B. Mobasher, T. Murayama, S. Sasaki, D. B. Sander, D. Schiminovich, Y. Shioya, P. Shopbell, J. Silverman, V. Smolčić, J. Surace, Y. Taniguchi, D. Thompson, J. R. Trump, M. Urry, M. Zamojski, and Beaussier, Catherine

Subjects
QSOS, catalog, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Photometry (optics), [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], catalogs, methods: miscellaneous, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Photometric redshift, Physics, 010308 nuclear & particles physics, Astrophysics (astro-ph), Astrophysics::Instrumentation and Methods for Astrophysics, Sigma, Astronomy and Astrophysics, Galaxy, Redshift, Stars, [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Space and Planetary Science, Spectral energy distribution, Astrophysics::Earth and Planetary Astrophysics
Abstract

We present photometric redshifts and spectral energy distribution (SED) classifications for a sample of 1542 optically identified sources detected with XMM in the COSMOS field. Our template fitting classifies 46 sources as stars and 464 as non-active galaxies, while the remaining 1032 require templates with an AGN contribution. High accuracy in the derived photometric redshifts was accomplished as the result of 1) photometry in up to 30 bands with high significance detections, 2) a new set of SED templates including 18 hybrids covering the far-UV to mid-infrared, which have been constructed by the combination of AGN and non-active galaxies templates, and 3) multi-epoch observations that have been used to correct for variability (most important for type 1 AGN). The reliability of the photometric redshifts is evaluated using the sub-sample of 442 sources with measured spectroscopic redshifts. We achieved an accuracy of $\sigma_{\Delta z/(1+z_{spec})} = 0.014$ for i$_{AB}^*, Comment: Accepted for publication in ApJ

Published
2008

19. Relativistic boost as the cause of periodicity in a massive black-hole binary candidate.

Author

D'Orazio DJ, Haiman Z, and Schiminovich D

Abstract

Because most large galaxies contain a central black hole, and galaxies often merge, black-hole binaries are expected to be common in galactic nuclei. Although they cannot be imaged, periodicities in the light curves of quasars have been interpreted as evidence for binaries, most recently in PG 1302-102, which has a short rest-frame optical period of four years (ref. 6). If the orbital period of the black-hole binary matches this value, then for the range of estimated black-hole masses, the components would be separated by 0.007-0.017 parsecs, implying relativistic orbital speeds. There has been much debate over whether black-hole orbits could be smaller than one parsec (ref. 7). Here we report that the amplitude and the sinusoid-like shape of the variability of the light curve of PG 1302-102 can be fitted by relativistic Doppler boosting of emission from a compact, steadily accreting, unequal-mass binary. We predict that brightness variations in the ultraviolet light curve track those in the optical, but with a two to three times larger amplitude. This prediction is relatively insensitive to the details of the emission process, and is consistent with archival ultraviolet data. Follow-up ultraviolet and optical observations in the next few years can further test this prediction and confirm the existence of a binary black hole in the relativistic regime.

Published
2015
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20. Delta-doped electron-multiplied CCD with absolute quantum efficiency over 50% in the near to far ultraviolet range for single photon counting applications.

Author

Nikzad S, Hoenk ME, Greer F, Jacquot B, Monacos S, Jones TJ, Blacksberg J, Hamden E, Schiminovich D, Martin C, and Morrissey P

Subjects
Electrons, Equipment Design, Photons, Silicon chemistry, Optical Devices, Quantum Theory, Radiometry instrumentation, Ultraviolet Rays
Abstract

We have used molecular beam epitaxy (MBE) based delta-doping technology to demonstrate nearly 100% internal quantum efficiency (QE) on silicon electron-multiplied charge-coupled devices (EMCCDs) for single photon counting detection applications. We used atomic layer deposition (ALD) for antireflection (AR) coatings and achieved atomic-scale control over the interfaces and thin film materials parameters. By combining the precision control of MBE and ALD, we have demonstrated more than 50% external QE in the far and near ultraviolet in megapixel arrays. We have demonstrated that other important device performance parameters such as dark current are unchanged after these processes. In this paper, we briefly review ultraviolet detection, report on these results, and briefly discuss the techniques and processes employed., (© 2012 Optical Society of America)

Published
2012
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21. Ultraviolet antireflection coatings for use in silicon detector design.

Author

Hamden ET, Greer F, Hoenk ME, Blacksberg J, Dickie MR, Nikzad S, Martin DC, and Schiminovich D

Abstract

We report on the development of coatings for a charged-coupled device (CCD) detector optimized for use in a fixed dispersion UV spectrograph. Because of the rapidly changing index of refraction of Si, single layer broadband antireflection (AR) coatings are not suitable to increase quantum efficiency at all wavelengths of interest. Instead, we describe a creative solution that provides excellent performance over UV wavelengths. We describe progress in the development of a coated CCD detector with theoretical quantum efficiencies (QEs) of greater than 60% at wavelengths from 120 to 300 nm. This high efficiency may be reached by coating a backside-illuminated, thinned, delta-doped CCD with a series of thin film AR coatings. The materials tested include MgF(2) (optimized for highest performance from 120-150 nm), SiO(2) (150-180 nm), Al(2)O(3) (180-240 nm), MgO (200-250 nm), and HfO(2) (240-300 nm). A variety of deposition techniques were tested and a selection of coatings that minimized reflectance on a Si test wafer were applied to functional devices. We also discuss future uses and improvements, including graded and multilayer coatings., (© 2011 Optical Society of America)

Published
2011
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22. Massive star formation within the Leo 'primordial' ring.

Author

Thilker DA, Donovan J, Schiminovich D, Bianchi L, Boissier S, de Paz AG, Madore BF, Martin DC, and Seibert M

Abstract

Few intergalactic, plausibly primordial clouds of neutral atomic hydrogen (H(i)) have been found in the local Universe, suggesting that such structures have either dispersed, become ionized or produced a stellar population on gigayear timescales. The Leo ring, a massive (M(H(i)) approximately 1.8 x 10(9)M[symbol: see text], M[symbol: see text] denoting the solar mass), 200-kpc-wide structure orbiting the galaxies M105 and NGC 3384 with a 4-Gyr period, is a candidate primordial cloud. Despite repeated atttempts, it has previously been seen only from H i emission, suggesting the absence of a stellar population. Here we report the detection of ultraviolet light from gaseous substructures of the Leo ring, which we attribute to recent massive star formation. The ultraviolet colour of the detected complexes is blue, implying the onset of a burst of star formation or continuous star formation of moderate (approximately 10(8)-yr) duration. Measured ultraviolet-visible photometry favours models with low metallicity (Z approximately Z[symbol: see text]/50-Z[symbol: see text]/5, Z[symbol: see text] denoting the solar metallicity), that is, a low proportion of elements heavier than helium, although spectroscopic confirmation is needed. We speculate that the complexes are dwarf galaxies observed during their formation, but distinguished by their lack of a dark matter component. In this regard, they resemble tidal dwarf galaxies, although without the enrichment preceding tidal stripping. If structures like the Leo ring were common in the early Universe, they may have produced a large, yet undetected, population of faint, metal-poor, halo-lacking dwarf galaxies.

Published
2009
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23. A turbulent wake as a tracer of 30,000 years of Mira's mass loss history.

Author

Martin DC, Seibert M, Neill JD, Schiminovich D, Forster K, Rich RM, Welsh BY, Madore BF, Wheatley JM, Morrissey P, and Barlow TA

Abstract

Mira is one of the first variable stars ever discovered and it is the prototype (and also the nearest example) of a class of low-to-intermediate-mass stars in the late stages of stellar evolution. These stars are relatively common and they return a large fraction of their original mass to the interstellar medium (ISM) (ref. 2) through a processed, dusty, molecular wind. Thus stars in Mira's stage of evolution have a direct impact on subsequent star and planet formation in their host galaxy. Previously, the only direct observation of the interaction between Mira-type stellar winds and the ISM was in the infrared. Here we report the discovery of an ultraviolet-emitting bow shock and turbulent wake extending over 2 degrees on the sky, arising from Mira's large space velocity and the interaction between its wind and the ISM. The wake is visible only in the far ultraviolet and is consistent with an unusual emission mechanism whereby molecular hydrogen is excited by turbulent mixing of cool molecular gas and shock-heated gas. This wind wake is a tracer of the past 30,000 years of Mira's mass-loss history and provides an excellent laboratory for studying turbulent stellar wind-ISM interactions.

Published
2007
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24. An ancient nova shell around the dwarf nova Z Camelopardalis.

Author

Shara MM, Martin CD, Seibert M, Rich RM, Salim S, Reitzel D, Schiminovich D, Deliyannis CP, Sarrazine AR, Kulkarni SR, Ofek EO, Brosch N, Lépine S, Zurek D, De Marco O, and Jacoby G

Abstract

Cataclysmic variables (classical novae and dwarf novae) are binary star systems in which a red dwarf transfers hydrogen-rich matter, by way of an accretion disk, to its white dwarf companion. In dwarf novae, an instability is believed to episodically dump much of the accretion disk onto the white dwarf. The liberation of gravitational potential energy then brightens these systems by up to 100-fold every few weeks or months. Thermonuclear-powered eruptions thousands of times more luminous occur in classical novae, accompanied by significant mass ejection and formation of clearly visible shells from the ejected material. Theory predicts that the white dwarfs in all dwarf novae must eventually accrete enough mass to undergo classical nova eruptions. Here we report a shell, an order of magnitude more extended than those detected around many classical novae, surrounding the prototypical dwarf nova Z Camelopardalis. The derived shell mass matches that of classical novae, and is inconsistent with the mass expected from a dwarf nova wind or a planetary nebula. The shell observationally links the prototypical dwarf nova Z Camelopardalis with an ancient nova eruption and the classical nova process.

Published
2007
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25. Suppression of star formation in early-type galaxies by feedback from supermassive black holes.

Author

Schawinski K, Khochfar S, Kaviraj S, Yi SK, Boselli A, Barlow T, Conrow T, Forster K, Friedman PG, Martin DC, Morrissey P, Neff S, Schiminovich D, Seibert M, Small T, Wyder TK, Bianchi L, Donas J, Heckman T, Lee YW, Madore B, Milliard B, Rich RM, and Szalay A

Abstract

Detailed high-resolution observations of the innermost regions of nearby galaxies have revealed the presence of supermassive black holes. These black holes may interact with their host galaxies by means of 'feedback' in the form of energy and material jets; this feedback affects the evolution of the host and gives rise to observed relations between the black hole and the host. Here we report observations of the ultraviolet emissions of massive early-type galaxies. We derive an empirical relation for a critical black-hole mass (as a function of velocity dispersion) above which the outflows from these black holes suppress star formation in their hosts by heating and expelling all available cold gas. Supermassive black holes are negligible in mass compared to their hosts but nevertheless seem to play a critical role in the star formation history of galaxies.

Published
2006
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26. Distributed aspects of the response to siphon touch in Aplysia: spread of stimulus information and cross-correlation analysis.

Author

Tsau Y, Wu JY, Höpp HP, Cohen LB, Schiminovich D, and Falk CX

Subjects
Animals, Ganglia, Invertebrate physiology, Time Factors, Aplysia physiology, Central Nervous System physiology, Sensation physiology, Touch physiology
Abstract

We examined two aspects of the response to siphon stimulation in an attempt to test the hypothesis that the Aplysia CNS functions as a distributed system. First, we estimated the number of central neurons that respond to a light touch to the siphon skin. We made voltage-sensitive dye recordings from the abdominal, pleural, pedal, and cerebral ganglia. From these recordings we estimated that 220 abdominal neurons, 110 pleural neurons, and 650 pedal neurons were affected by the light touch. Thus, the information about this mild and localized stimulus is very widely distributed within the Aplysia CNS. This result allows the possibility that the Aplysia CNS functions as a distributed system. If only a small number of neurons had responded to the touch, it would have supported the conclusion that the gill-withdrawal reflex could be generated by a small, dedicated circuit. Second, we searched for correlations between the spike times of the individual abdominal ganglion neurons. Two time scales were examined: a millisecond time scale corresponding to the duration of a fast synaptic potential and a seconds time scale corresponding to the duration of the gill-withdrawal movement. Neuron pairs with highly correlated spike activity on a millisecond time scale must be connected by (or have a common input that uses) relatively powerful, fast, excitatory synapses. We expected that this kind of synaptic interaction would be relatively rare in nervous systems that functioned in a distributed manner. Indeed, only 0.3% of the neuron pairs had correlation coefficients of 0.15 or greater. These correlations accounted for approximately 2% of the action potentials generated in response to siphon stimulation. Thus, large, fast excitatory synaptic interactions appear to be relatively unimportant. This result is consistent with the hypothesis that the abdominal ganglion functions as a distributed system. When the longer time scale was used for the cross-correlograms, a large fraction of the cell pairs had correlated activity because many neurons are activated by the stimulus. It was not possible to interpret the slow correlations in terms of actual synaptic interactions between individual neurons. Our results are consistent with the possibility that the abdominal ganglion functions in a distributed manner. However, this evaluation is indirect and thus only tentative conclusions can be drawn. Evidence from several sources suggests that the neuronal interactions for generating the Aplysia gill-withdrawal reflex are complex.

Published
1994

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