Shards: an optical spectro-photometric survey of distant galaxies



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Pérez González, Pablo Guillermo and Cava, Antonio and Barro, Guillermo and Villar, Victor and Cardiel López, Nicolás and Espino, Néstor and Gallego Maestro, Jesús and Zamorano Calvo, Jaime (2013) Shards: an optical spectro-photometric survey of distant galaxies. Astrophysical journal, 762 (1). ISSN 0004-637X

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We present the Survey for High-z Absorption Red and Dead Sources (SHARDS), an ESO/GTC Large Program carried out using the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC). SHARDS is an ultra-deep optical spectro-photometric survey of the GOODS-N field covering 130 arcmin(2) at wavelengths between 500 and 950 nm with 24 contiguous medium-band filters (providing a spectral resolution R similar to 50). The data reach an AB magnitude of 26.5 (at least at a 3 sigma level) with sub-arcsec seeing in all bands. SHARDS' main goal is to obtain accurate physical properties of intermediate-and high-z galaxies using well-sampled optical spectral energy distributions (SEDs) with sufficient spectral resolution to measure absorption and emission features, whose analysis will provide reliable stellar population and active galactic nucleus (AGN) parameters. Among the different populations of high-z galaxies, SHARDS' principal targets are massive quiescent galaxies at z > 1, whose existence is one of the major challenges facing current hierarchical models of galaxy formation. In this paper, we outline the observational strategy and include a detailed discussion of the special reduction and calibration procedures which should be applied to the GTC/OSIRIS data. An assessment of the SHARDS data quality is also performed. We present science demonstration results on the detection and study of emission-line galaxies (star-forming objects and AGNs) at z = 0-5. We also analyze the SEDs for a sample of 27 quiescent massive galaxies with spectroscopic redshifts in the range 1.0 < z less than or similar to 1.4. We discuss the improvements introduced by the SHARDS data set in the analysis of their star formation history and stellar properties. We discuss the systematics arising from the use of different stellar population libraries, typical in this kind of study. Averaging the results from the different libraries, we find that the UV-to-MIR SEDs of the massive quiescent galaxies at z = 1.0-1.4 are well described by an exponentially decaying star formation history with scale t = 100-200 Myr, age around 1.5-2.0 Gyr, solar or slightly sub-solar metallicity, and moderate extinction, A(V) similar to 0.5 mag. We also find that galaxies with masses above M* are typically older than lighter galaxies, as expected in a downsizing scenario of galaxy formation. This trend is, however, model dependent, i.e., it is significantly more evident in the results obtained with some stellar population synthesis libraries, and almost absent in others.

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©2013 The American Astronomical Society. We acknowledge support from the Spanish Programa Nacional de Astronomía y Astrofísica under grants AYA2009-07723-E and AYA2009-10368. SHARDS has been funded by the Spanish MICINN/MINECO under the Consolider-Ingenio 2010 Program grant CSD2006-00070: First Science with the GTC. O.G.-M., C.M.-T., J.M.R.-E., and J.R.-Z. wish to acknowledge support from grant AYA2010-21887-C04-04. A.A.-H. and A.H.-C. acknowledge financial support from the Universidad de Cantabria through the Augusto G. Linares Program. This work has made use of the Rainbow Cosmological Surveys Database, which is operated by the Universidad Complutense de Madrid (UCM). This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France. Based on observations made with the Gran Telescopio Canarias (GTC), installed at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, in the island of La Palma. We thank all the GTC Staff for their support and enthusiasm with the SHARDS project, and we especially acknowledge the help from Antonio Cabrera and René Rutten. The work is also based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck-Institut fur Astronomie and the Instituto de Astrofísica de Andalucia (CSIC). We thank the referee for her/his very useful and positive comments.

Uncontrolled Keywords:Star-forming galaxies; Subaru deep field; Alpha luminosity function; Similar-to 2; Old stellar populations; Dust-obscured galaxies; Formation rate density; Baryon acoustic-oscillations; Extragalactic legacy survey; Probe wmap observations
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
Sciences > Physics > Atmospheric physics
ID Code:27816
Deposited On:19 Dec 2014 10:33
Last Modified:10 Dec 2018 15:05

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