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251. A z = 1.82 Analog of Local Ultra-massive Elliptical Galaxies

Author

S. J. Lilly, Michele Cappellari, Yoshihiko Yamada, Olivier Ilbert, David B. Sanders, Kentaro Motohara, Raphael Gobat, Mauro Giavalisco, Alvio Renzini, Alessandro Cimatti, Kouji Ohta, H. J. McCracken, Y. Taniguchi, Xu Kong, Peter Capak, M. Carollo, Naoyuki Tamura, C. Mancini, Masato Onodera, N. Z. Scoville, Nobuo Arimoto, Emanuele Daddi, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Sub-department of Astrophysics [Oxford], Department of Physics [Oxford], University of Oxford [Oxford]-University of Oxford [Oxford], National Astronomical Observatory of Japan (NAOJ), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Spitzer Science Center, California Institute of Technology (CALTECH), Institute for Astronomy [Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Dipartimento di Astronomia, Università di Bologna [Bologna] (UNIBO), Department of Astronomy [Amherst], University of Massachusetts [Amherst] (UMass Amherst), University of Massachusetts System (UMASS)-University of Massachusetts System (UMASS), 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), Center for Astrophysics [Hefei], University of Science and Technology of China [Hefei] (USTC), Institute of Astronomy, The University of Tokyo, Department of Astronomy, Kyoto University [Kyoto], Institute for Astronomy [Honolulu], University of Hawai‘i [Mānoa] (UHM), Research Center for Space and Cosmic Evolution (RCSCE), Ehime University [Matsuyama], UPGAL, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), The University of Tokyo (UTokyo), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Oxford-University of Oxford, 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), Kyoto University, Ehime University [Matsuyama, Japon], M. Onodera, E. Daddi, R. Gobat, M. Cappellari, N. Arimoto, A. Renzini, Y. Yamada, H. J. McCracken, C. Mancini, P. Capak, M. Carollo, A. Cimatti, M. Giavalisco, O. Ilbert, X. Kong, S. Lilly, K. Motohara, K. Ohta, D. B. Sander, N. Scoville, N. Tamura, and Y. Taniguchi

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Stellar population, Stellar mass, media_common.quotation_subject, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, media_common, Physics, 010308 nuclear & particles physics, Velocity dispersion, Astronomy and Astrophysics, Virial mass, Galaxy, Redshift, Universe, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Space and Planetary Science, Elliptical galaxy, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present observations of a very massive galaxy at z=1.82 which show that its morphology, size, velocity dispersion and stellar population properties that are fully consistent with those expected for passively evolving progenitors of today's giant ellipticals. These findings are based on a deep optical rest-frame spectrum obtained with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru telescope of a high-z passive galaxy candidate (pBzK) from the COSMOS field, for which we accurately measure its redshift of z=1.8230 and obtain an upper limit on its velocity dispersion sigma_star, ApJ Letters in press; 9 pages; 4 figures; 1 table; emulateapj.cls

Published
2010
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252. Redshift-space distortions as a probe of dark energy

Author

Guzzo L., Pierleoni M., Meneux B., Le Fevre O., Marinoni C., Garilli B., Blaizot J., De Lucia G., Pollo A., McCracken H. J., Bottini D., Le Brun V., Maccagni D., Picat J. P., Scaramella R., Scodeggio M., Tresse L., Vettolani G., Zanichelli A., Adami C., Arnouts S., Bardelli S., Bolzonella M., Bongiorno A., Cappi A., Charlot S., Ciliegi P., Contini T., Cucciati O., De la Torre S., Foucaud S., Franzetti P., Gavignaud I., Ilbert O., Iovino A., Lamareille F., Marano B., Mazure A., Memeo P., Mellier Y., Merighi R., Moscardini L., Paltani S., Pello R., Pozzetti L., Radovich M., Vergani D., Zamorani G., Zucca E., BRANCHINI, ENZO FRANCO, L. Guzzo, M. Pierleoni, B. Meneux, E. Branchini, O. . Fevre, C. Marinoni, B. Garilli, J. Blaizot, G. . Lucia, A. Pollo, H. J. McCracken, D. Bottini, V. . Brun, D. Maccagni, J. P. Picat, R. Scaramella, M. Scodeggio, L. Tresse, G. Vettolani, A. Zanichelli, C. Adami, S. Arnout, S. Bardelli, M. Bolzonella, A. Bongiorno, A. Cappi, S. Charlot, P. Ciliegi, T. Contini, O. Cucciati, S. . La, S. Foucaud, P. Franzetti, I. Gavignaud, O. Ilbert, A. Iovino, F. Lamareille, B. Marano, A. Mazure, P. Memeo, Y. Mellier, R. Merighi, L. Moscardini, S. Paltani, R. Pello, L. Pozzetti, M. Radovich, D. Vergani, G. Zamorani, E. Zucca, Guzzo, L., Pierleoni, M., Meneux, B., Branchini, ENZO FRANCO, Le Fevre, O., Marinoni, C., Garilli, B., Blaizot, J., De Lucia, G., Pollo, A., Mccracken, H. J., Bottini, D., Le Brun, V., Maccagni, D., Picat, J. P., Scaramella, R., Scodeggio, M., Tresse, L., Vettolani, G., Zanichelli, A., Adami, C., Arnouts, S., Bardelli, S., Bolzonella, M., Bongiorno, A., Cappi, A., Charlot, S., Ciliegi, P., Contini, T., Cucciati, O., De la Torre, S., Foucaud, S., Franzetti, P., Gavignaud, I., Ilbert, O., Iovino, A., Lamareille, F., Marano, B., Mazure, A., Memeo, P., Mellier, Y., Merighi, R., Moscardini, L., Paltani, S., Pello, R., Pozzetti, L., Radovich, M., Vergani, D., Zamorani, G., and Zucca, E.

Subjects
pancake, etc.) – Origin and formation of the Universe, great wall, Astrophysics::Cosmology and Extragalactic Astrophysics, Dark energy. – Superclusters, large-scale structure of the Universe (including void
Abstract

Measurements of the growth rate of structure f at different redshifts can discriminate the origin of cosmic acceleration. Coupled to estimates of the expansion rate H(z) as provided by Type-la supernovae or Baryonic Acoustic Oscillations, accurate measurements of f(z) are able to distinguish "dark energy" models from theories with modified gravity, as, e.g., braneworld models. These two classes are degenerate when considering the expansion history alone. We have recently shown (Nature, 451 (2008) 541) that redshift-space distortions in the clustering pattern of galaxies measured from large redshift surveys represent an extremely promising technique to trace f (z) back in time. We have measured the distortion parameter beta at z similar to 0.8 using the currently largest field of the VVDS-Wide survey, that includes more than 10000 galaxy redshifts to I(AB) = 22.5 over 4 deg(2). We obtain 0 - 0.70 +/- 0.26, corresponding to a growth rate f = 0.91 +/- 0.36, consistent with the simplest cosmological-constant scenario. Error bars are still large compared with the difference among models. However, next-generation deep surveys with N > 100000 redshifts over similar to 100deg(2) or larger, will be able to use this test as an accurate probe of the origin of cosmic acceleration.

Published
2007

253. The VIRMOS-VLT Deep Survey: the last 10 billion years of evolution of galaxy clustering

Author

Pollo, A., Guzzo, L., Le Fèvre, O., Meneux, B., Cappi, A., Mccracken, H. J., Iovino, A., Marinoni, C., Bottini, D., Garilli, B., Le Brun, V. L., Maccagni, D., Picat, J. P., Scaramella, R., Marco Scodeggio, Tresse, L., Vettolani, G., Zanichelli, A., Adami, C., Arnouts, S., Bardelli, S., Bolzonella, M., Charlot, S., Ciliegi, P., Contini, T., Foucaud, S., Franzetti, P., Gavignaud, I., Ilbert, O., Marano, B., Mazure, A., Merighi, R., Paltani, S., Pellò, R., Pozzetti, L., Radovich, M., Zamorani, G., Zucca, E., Bondi, M., Bongiorno, A., Brinchmann, J., Cucciati, O., La Torre, S., Lamareille, F., Mellier, Y., Merluzzi, P., Temporin, S., Vergani, D., Walcher, C. J., INAF - Osservatorio Astronomico di Brera (OAB), Istituto Nazionale di Astrofisica (INAF), 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), A. Pollo, L. Guzzo, O. Le Fevre, B. Meneux, A. Cappi, H. J. McCracken, A. Iovino, C. Marinoni, D. Bottini, B. Garilli, V. L. Le, D. Maccagni, J. P. Picat, R. Scaramella, M. Scodeggio, L. Tresse, G. Vettolani, A. Zanichelli, C. Adami, S. Arnout, S. Bardelli, M. Bolzonella, S. Charlot, P. Ciliegi, T. Contini, S. Foucaud, P. Franzetti, I. Gavignaud, O. Ilbert, B. Marano, A. Mazure, R. Merighi, S. Paltani, R. Pello, L. Pozzetti, M. Radovich, G. Zamorani, E. Zucca, M. Bondi, A. Bongiorno, J. Brinchmann, O. Cucciati, S. . la, F. Lamareille, Y. Mellier, P. Merluzzi, S. Temporin, D. Vergani, C. J. Walcher, 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
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], SPECTRAL TYPE, VIMOS, LUMINOSITY, DEPENDENCE, Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We discuss the evolution of clustering of galaxies in the Universe from the present epoch back to z ~ 2, using the first-epoch data from the VIMOS-VLT Deep Survey (VVDS). We present the evolution of the projected two-point correlation function of galaxies for the global galaxy population, as well as its dependence on galaxy intrinsic luminosities and spectral types. While we do not find strong variations of the correlation function parameters with redshift for the global galaxy population, the clustering of objects with different intrinsic luminosities evolved significantly during last 8-10 billion years. Our findings indicate that bright galaxies in the past traced higher density peaks than they do now and that the shape of the correlation function of most luminous galaxies is different from observed for their local counterparts, which is a supporting evidence of a non-trivial evolution of the galaxy vs. dark matter bias., Comment: 4 pages, 4 figures, to appear in the proceedings of the conference 'At the Edge of the Universe' (9-13 October 2006, Sintra, Portugal)

Published
2006

254. THE BULK OF THE BLACK HOLE GROWTH SINCEz∼ 1 OCCURS IN A SECULAR UNIVERSE: NO MAJOR MERGER-AGN CONNECTION

Author

Yoshi Taniguchi, Anton M. Koekemoer, Kartik Sheth, Mara Salvato, Takamitsu Miyaji, Mauricio Cisternas, Thorsten Lisker, Marcella Brusa, Knud Jahnke, Francesca Civano, Aday R. Robaina, Nick Scoville, Alexie Leauthaud, Elisabeta Lusso, Simon J. Lilly, Rene Andrae, Jonathan R. Trump, Katherine J. Inskip, Olivier Ilbert, Nico Cappelluti, Chris Impey, Jeyhan S. Kartaltepe, Peter Capak, Marco Scodeggio, M. Cisterna, K. Jahnke, K. J. Inskip, J. Kartaltepe, A. M. Koekemoer, T. Lisker, A. R. Robaina, M. Scodeggio, K. Sheth, J. R. Trump, R. Andrae, T. Miyaji, E. Lusso, M. Brusa, P. Capak, N. Cappelluti, F. Civano, O. Ilbert, C. D. Impey, A. Leauthaud, S. J. Lilly, M. Salvato, N. Z. Scoville, Y. Taniguchi, Laboratoire d'Astrophysique de Marseille (LAM), 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
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Active galactic nucleus, Direct evidence, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, galaxies: active, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy merger, 01 natural sciences, quasars: general, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, media_common, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Significant difference, Astronomy and Astrophysics, Accretion (astrophysics), Galaxy, Universe, Black hole, Space and Planetary Science, galaxies: interaction, Astrophysics::Earth and Planetary Astrophysics, galaxies: evolution, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

What is the relevance of major mergers and interactions as triggering mechanisms for active galactic nuclei (AGN) activity? To answer this longstanding question, we analyze 140 XMM-selected AGN host galaxies and a matched control sample of 1264 inactive galaxies over z~0.3-1.0 and log(M_*/M_sun)85%) of the AGN host galaxies do not show strong distortions, and (2) there is no significant difference in the distortion fractions between active and inactive galaxies. Our findings provide the best direct evidence that, since z~1, the bulk of black hole accretion has not been triggered by major galaxy mergers, therefore arguing that the alternative mechanisms, i.e., secular processes and minor interactions, are the leading triggers for the episodes of major black hole growth. We also exclude an alternative interpretation of our results: a significant time lag between merging and the observability of the AGN phase could wash out the most significant merging signatures, explaining the lack of enhancement of strong distortions on the AGN hosts. We show that this alternative scenario is unlikely due to: (1) recent major mergers being ruled out for the majority of sources due to the high fraction of disk-hosted AGN, (2) the lack of a significant X-ray signal in merging inactive galaxies as a signature of a potential buried AGN, and (3) the low levels of soft X-ray obscuration for AGN hosted by interacting galaxies, in contrast to model predictions., 15 pages, 9 figures, accepted for publication in ApJ

Published
2010
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255. The VVDS-Deep Survey: the growth of bright galaxies by minor mergers since z = 1

Author

Carlos López-Sanjuan, Le Fèvre, O., Ravel, L., Cucciati, O., Ilbert, O., Tresse, L., Bardelli, S., Bolzonella, M., Contini, T., Garilli, B., Guzzo, L., Maccagni, D., Mccracken, H. J., Mellier, Y., Pollo, A., Vergani, D., Zucca, E., M. R. Zapatero Osorio, J. Gorgas, J. Maíz Apellániz, J. R. Pardo, and A. Gil de Paz., C. Lopez-Sanjuan, O. . Fevre, L. . Ravel, O. Cucciati, O. Ilbert, L. Tresse, S. Bardelli, M. Bolzonella, T. Contini, B. Garilli, L. Guzzo, D. Maccagni, H. J. McCracken, Y. Mellier, A. Pollo, D. Vergani, and E. Zucca

Subjects
galaxies: interaction, galaxies: formation, Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies: evolution, Astrophysics::Galaxy Astrophysics, galaxies: statistics
Abstract

In this work we measure the merger fraction, f_m, of L_B >= L^*_B galaxies in the VVDS-Deep spectroscopic Survey. We define kinematical close pairs as those galaxies with a separation in the sky plane 5h^{-1} kpc < r_p = 1/4 and 1/10 = L^*_B galaxies has grown ˜ 25% since z ˜ 1 because of minor and major mergers. The relative contribution of the mass growth by merging is ˜ 25% due to minor mergers and ˜ 75% due to major ones. The relative effect of merging is more important for red galaxies, with those subject to 0.6 minor and 0.7 major mergers since z ˜ 1, which leads to a mass growth of ˜ 40% and a size increase by a factor of 2. These results show that minor merging is a significant but not dominant mechanism driving the mass growth of galaxies in the last ˜ 8 Gyr.

256. The VIMOS VLT deep survey: Clustering and the role of environment in galaxy evolution

Author

Le Fevre, O., Cucciati, O., Guzzo, L., Olivier Ilbert, Lovino, A., Marinoni, C., Meneux, B., Paltani, S., Pollo, A., Bottini, D., Garilli, B., Le Brun, V., Maccagni, D., Picat, J. P., Scaramella, R., Scodeggio, M., Tresse, L., Vettolani, G., Zanichelli, A., Adami, C., Arnaboldi, M., Arnouts, S., Bardelli, S., Bolzonella, M., Cappi, A., Charlot, S., Ciliegi, P., Contini, T., Foucaud, S., Franzetti, P., Gavignaud, I., Mccracken, H. J., Marano, B., Mazure, A., Merighi, R., Pello, R., Pozzetti, L., Radovich, M., Zamorani, G., Zucca, E., Bondi, M., Bongiorno, A., Busarello, G., La Torre, S., Gregorini, L., Lamareille, F., Mathez, G., Mellier, Y., Merluzzi, P., Ripepi, V., Rizzo, D., O. Le Fevre, O. Cucciati, L. Guzzo, O. Ilbert, A. Iovino, C. Marinoni, B. Meneux, S. Paltani, A. Pollo, D. Bottini, B. Garilli, V. . Brun, D. Maccagni, J. P. Picat, R. Scaramella, M. Scodeggio, L. Tresse, G. Vettolani, A. Zanichelli, C. Adami, M. Arnaboldi, S. Arnout, S. Bardelli, M. Bolzonella, A. Cappi, S. Charlot, P. Ciliegi, T. Contini, S. Foucaud, P. Franzetti, I. Gavignaud, H. J. McCracken, B. Marano, A. Mazure, R. Merighi, R. Pello, L. Pozzetti, M. Radovich, G. Zamorani, E. Zucca, M. Bondi, A. Bongiorno, G. Busarello, S. . La, L. Gregorini, F. Lamareille, G. Mathez, Y. Mellier, P. Merluzzi, V. Ripepi, and D. Rizzo

Subjects
LUMINOSITY, DEPENDENCE, DENSITY

257. Galaxies at redshifts 5 to 6 with systematically low dust content and high [C II] emission.

Author

Capak PL, Carilli C, Jones G, Casey CM, Riechers D, Sheth K, Carollo CM, Ilbert O, Karim A, LeFevre O, Lilly S, Scoville N, Smolcic V, and Yan L

Abstract

The rest-frame ultraviolet properties of galaxies during the first three billion years of cosmic time (redshift z > 4) indicate a rapid evolution in the dust obscuration of such galaxies. This evolution implies a change in the average properties of the interstellar medium, but the measurements are systematically uncertain owing to untested assumptions and the inability to detect heavily obscured regions of the galaxies. Previous attempts to measure the interstellar medium directly in normal galaxies at these redshifts have failed for a number of reasons, with two notable exceptions. Here we report measurements of the forbidden C ii emission (that is, [C II]) from gas, and the far-infrared emission from dust, in nine typical star-forming galaxies about one billion years after the Big Bang (z ≈ 5-6). We find that these galaxies have thermal emission that is less than 1/12 that of similar systems about two billion years later, and enhanced [C II] emission relative to the far-infrared continuum, confirming a strong evolution in the properties of the interstellar medium in the early Universe. The gas is distributed over scales of one to eight kiloparsecs, and shows diverse dynamics within the sample. These results are consistent with early galaxies having significantly less dust than typical galaxies seen at z < 3 and being comparable in dust content to local low-metallicity systems.

Published
2015
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258. A test of the nature of cosmic acceleration using galaxy redshift distortions.

Author

Guzzo L, Pierleoni M, Meneux B, Branchini E, Le Fèvre O, Marinoni C, Garilli B, Blaizot J, De Lucia G, Pollo A, McCracken HJ, Bottini D, Le Brun V, Maccagni D, Picat JP, Scaramella R, Scodeggio M, Tresse L, Vettolani G, Zanichelli A, Adami C, Arnouts S, Bardelli S, Bolzonella M, Bongiorno A, Cappi A, Charlot S, Ciliegi P, Contini T, Cucciati O, de la Torre S, Dolag K, Foucaud S, Franzetti P, Gavignaud I, Ilbert O, Iovino A, Lamareille F, Marano B, Mazure A, Memeo P, Merighi R, Moscardini L, Paltani S, Pellò R, Perez-Montero E, Pozzetti L, Radovich M, Vergani D, Zamorani G, and Zucca E

Abstract

Observations of distant supernovae indicate that the Universe is now in a phase of accelerated expansion the physical cause of which is a mystery. Formally, this requires the inclusion of a term acting as a negative pressure in the equations of cosmic expansion, accounting for about 75 per cent of the total energy density in the Universe. The simplest option for this 'dark energy' corresponds to a 'cosmological constant', perhaps related to the quantum vacuum energy. Physically viable alternatives invoke either the presence of a scalar field with an evolving equation of state, or extensions of general relativity involving higher-order curvature terms or extra dimensions. Although they produce similar expansion rates, different models predict measurable differences in the growth rate of large-scale structure with cosmic time. A fingerprint of this growth is provided by coherent galaxy motions, which introduce a radial anisotropy in the clustering pattern reconstructed by galaxy redshift surveys. Here we report a measurement of this effect at a redshift of 0.8. Using a new survey of more than 10,000 faint galaxies, we measure the anisotropy parameter beta = 0.70 +/- 0.26, which corresponds to a growth rate of structure at that time of f = 0.91 +/- 0.36. This is consistent with the standard cosmological-constant model with low matter density and flat geometry, although the error bars are still too large to distinguish among alternative origins for the accelerated expansion. The correct origin could be determined with a further factor-of-ten increase in the sampled volume at similar redshift.

Published
2008
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259. A large population of galaxies 9 to 12 billion years back in the history of the Universe.

Author

Le Fèvre O, Paltani S, Arnouts S, Charlot S, Foucaud S, Ilbert O, McCracken HJ, Zamorani G, Bottini D, Garilli B, Le Brun V, Maccagni D, Picat JP, Scaramella R, Scodeggio M, Tresse L, Vettolani G, Zanichelli A, Adami C, Bardelli S, Bolzonella M, Cappi A, Ciliegi P, Contini T, Franzetti P, Gavignaud I, Guzzo L, Iovino A, Marano B, Marinoni C, Mazure A, Meneux B, Merighi R, Pellò R, Pollo A, Pozzetti L, Radovich M, Zucca E, Arnaboldi M, Bondi M, Bongiorno A, Busarello G, Gregorini L, Lamareille F, Mathez G, Mellier Y, Merluzzi P, Ripepi V, and Rizzo D

Abstract

To understand the evolution of galaxies, we need to know as accurately as possible how many galaxies were present in the Universe at different epochs. Galaxies in the young Universe have hitherto mainly been identified using their expected optical colours, but this leaves open the possibility that a significant population remains undetected because their colours are the result of a complex mix of stars, gas, dust or active galactic nuclei. Here we report the results of a flux-limited I-band survey of galaxies at look-back times of 9 to 12 billion years. We find 970 galaxies with spectroscopic redshifts between 1.4 and 5. This population is 1.6 to 6.2 times larger than previous estimates, with the difference increasing towards brighter magnitudes. Strong ultraviolet continua (in the rest frame of the galaxies) indicate vigorous star formation rates of more than 10-100 solar masses per year. As a consequence, the cosmic star formation rate representing the volume-averaged production of stars is higher than previously measured at redshifts of 3 to 4.

Published
2005
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