IMPROVED AND QUALITY-ASSESSED EMISSION AND ABSORPTION LINE MEASUREMENTS IN SLOAN DIGITAL SKY SURVEY GALAXIES

We present a new database of absorption and emission-line measurements based on the entire spectral atlas from the Sloan Digital Sky Survey (SDSS) 7th data release of galaxies within a redshift of 0.2. Our work makes use of the publicly available penalized pixel-fitting (pPXF) and gas and absorption line fitting (gandalf) IDL codes, aiming to improve the existing measurements for stellar kinematics, the strength of various absorption-line features, and the flux and width of the emissions from different species of ionized gas. Our fit to the stellar continuum uses both standard stellar population models and empirical templates obtained by combining a large number of stellar spectra in order to fit a subsample of high-quality SDSS spectra for quiescent galaxies. Furthermore, our fit to the nebular spectrum includes an exhaustive list of both recombination and forbidden lines. Foreground Galactic extinction is implicitly treated in our models, whereas reddening in the SDSS galaxies is included in the form of a simple dust screen component affecting the entire spectrum that is accompanied by a second reddening component affecting only the ionized gas emission. In order to check for systematic departures from the rather standard set of assumptions that enters our models, we providemore » a quality assessment for our fit to the SDSS spectra in our sample, for both the stellar continuum and the nebular emissions and across different wavelength regions. This quality assessment also allows the identification of objects with either problematic data or peculiar features. We hope to foster the discovery potential of our database; therefore, our spectral fit is available to the community. For example, based on the quality assessment around the H{alpha} and [N II] {lambda}6584 lines, approximately 1% of the SDSS spectra classified as 'galaxies' by the SDSS pipeline do in fact require additional broad lines to be matched, even though they do not show a strong continuum from an active nucleus, as do the SDSS objects classified as 'quasars'. Finally, we provide new spectral templates for galaxies of different Hubble types, obtained by combining the results of our spectral fit for a subsample of 452 morphologically selected objects.« less

[1]  K. Abazajian,et al.  THE SEVENTH DATA RELEASE OF THE SLOAN DIGITAL SKY SURVEY , 2008, 0812.0649.

[2]  D. Ottaviani,et al.  Hγ and Hδ Absorption Features in Stars and Stellar Populations , 1997 .

[3]  A. Szalay,et al.  Galaxy Luminosity Functions to z~1 from DEEP2 and COMBO-17: Implications for Red Galaxy Formation , 2005, astro-ph/0506044.

[4]  David Burstein,et al.  Old stellar populations. 5: Absorption feature indices for the complete LICK/IDS sample of stars , 1994 .

[5]  Sandra M. Faber,et al.  MG and Fe absorption features in elliptical galaxies , 1992 .

[6]  Michele Cappellari,et al.  Adaptive spatial binning of integral-field spectroscopic data using Voronoi tessellations , 2003, astro-ph/0302262.

[7]  J. Lotz,et al.  AEGIS: THE NATURE OF THE HOST GALAXIES OF LOW-IONIZATION OUTFLOWS AT z < 0.6 , 2008, 0804.4312.

[8]  Walter A. Siegmund,et al.  The 2.5 m Telescope of the Sloan Digital Sky Survey , 2006, astro-ph/0602326.

[9]  D. Schlegel,et al.  Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds , 1998 .

[10]  M. Fukugita,et al.  The Sloan Digital Sky Survey Photometric System , 1996 .

[11]  Donald E. Osterbrock,et al.  Spectral Classification of Emission-Line Galaxies , 1987 .

[12]  L. Sodré,et al.  Semi‐empirical analysis of Sloan Digital Sky Survey galaxies – I. Spectral synthesis method , 2005 .

[13]  D. Fisher,et al.  Line Strengths and Line-Strength Gradients in S0 Galaxies , 1996 .

[14]  K. Schawinski,et al.  The SAURON project - XVI. On the sources of ionization for the gas in elliptical and lenticular galaxies , 2009, 0912.0275.

[15]  Roger L. Davies,et al.  Line-Strength Gradients in Elliptical Galaxies , 1993 .

[16]  The stellar populations of early-type galaxies in the Fornax cluster , 2000 .

[17]  J. Baldwin,et al.  ERRATUM - CLASSIFICATION PARAMETERS FOR THE EMISSION-LINE SPECTRA OF EXTRAGALACTIC OBJECTS , 1981 .

[18]  Harald Kuntschner,et al.  Line-of-sight velocity distribution corrections for Lick/IDS indices of early-type galaxies , 2004, astro-ph/0407219.

[19]  et al,et al.  The Sloan Digital Sky Survey Photometric Camera , 1998, astro-ph/9809085.

[20]  R. Bender,et al.  The Epochs of Early-Type Galaxy Formation as a Function of Environment , 2004, astro-ph/0410209.

[21]  Eric Emsellem,et al.  Parametric Recovery of Line‐of‐Sight Velocity Distributions from Absorption‐Line Spectra of Galaxies via Penalized Likelihood , 2003, astro-ph/0312201.

[22]  K. Schawinski,et al.  Observational evidence for AGN feedback in early-type galaxies , 2007, 0709.3015.

[23]  Alexander S. Szalay,et al.  Sloan digital sky survey: Early data release , 2002 .

[24]  R. Lupton,et al.  Astrometric Calibration of the Sloan Digital Sky Survey , 2002, astro-ph/0211375.

[25]  L. Kewley,et al.  The host galaxies and classification of active galactic nuclei , 2006, astro-ph/0605681.

[26]  The Effect of Environment on the Ultraviolet Color-Magnitude Relation of Early-Type Galaxies , 2006, astro-ph/0601036.

[27]  J. Brinchmann,et al.  ABSORPTION-LINE PROBES OF THE PREVALENCE AND PROPERTIES OF OUTFLOWS IN PRESENT-DAY STAR-FORMING GALAXIES , 2010, 1003.5425.

[28]  A. Cimatti,et al.  A catalogue of the Chandra Deep Field South with multi-colour classification and photometric redshifts from COMBO-17 , 2004, astro-ph/0403666.

[29]  Timothy M. Heckman,et al.  The host galaxies of active galactic nuclei , 2003 .

[30]  Iap,et al.  Galaxies with Wolf-Rayet signatures in the low-redshift Universe. A survey using the Sloan Digital Sky Survey , 2008, 0805.1073.

[31]  E. Emsellem,et al.  The SAURON project - VI. Line strength maps of 48 elliptical and lenticular galaxies , 2006, astro-ph/0602192.

[32]  J. Brinkmann,et al.  The environmental dependence of the relations between stellar mass, structure, star formation and nuclear activity in galaxies , 2004, astro-ph/0402030.

[33]  D. Osterbrock,et al.  The spectra of narrow-line Seyfert 1 galaxies , 1985 .

[34]  Max Pettini,et al.  The Mass-Metallicity Relation at z≳2 , 2006, astro-ph/0602473.

[35]  C. Lintott,et al.  Galaxy Zoo Green Peas: discovery of a class of compact extremely star-forming galaxies , 2009, 0907.4155.

[36]  D. Fisher,et al.  Line Strength Gradients in Elliptical and Brightest Cluster Galaxies , 1995 .

[37]  Space Telescope Sceince Institute,et al.  A two-arm gaseous spiral in the inner 200 pc of the early-type galaxy NGC 2974: signature of an inner bar , 2003, astro-ph/0308146.

[38]  The Host Galaxies of AGN , 2003, astro-ph/0304239.

[39]  V. Narayanan,et al.  Color Separation of Galaxy Types in the Sloan Digital Sky Survey Imaging Data , 2001, astro-ph/0107201.

[40]  G. Mcvittie.  Problems of extra-galactic research , 1962 .

[41]  F. Miller Maley,et al.  An Efficient Algorithm for Positioning Tiles in the Sloan Digital Sky Survey , 2001 .

[42]  G. Efstathiou,et al.  Line-strengths in early-type galaxies , 1990, Monthly Notices of the Royal Astronomical Society.

[43]  A. J. Cenarro,et al.  Medium-resolution isaac newton telescope library of empirical spectra , 2006 .

[44]  D. Schlegel,et al.  Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds , 1997, astro-ph/9710327.

[45]  E and S0 galaxies in the central part of the Coma cluster: ages, metal abundances and dark matter , 1999, astro-ph/9902250.

[46]  S. Faber,et al.  Old Stellar Populations. IV. Empirical Fitting Functions for Features in the Spectra of G and K Stars , 1993 .

[47]  G. Bruzual,et al.  Stellar population synthesis at the resolution of 2003 , 2003, astro-ph/0309134.

[48]  M. SubbaRao,et al.  Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Quasar Sample , 2002, astro-ph/0202251.

[49]  The SAURON project—V. Integral-field emission-line kinematics of 48 elliptical and lenticular galaxies , 2004, astro-ph/0404034.

[50]  L. Kewley,et al.  Theoretical Modeling of Starburst Galaxies , 2001, astro-ph/0106324.

[51]  Six-Color Photometry of Stars. VI. The Colors of Extragalactic Nebulae. , 1948 .

[52]  Garching,et al.  Stellar population models of Lick indices with variable element abundance ratios , 2003 .

[53]  M. Fukugita,et al.  Statistical Properties of Bright Galaxies in the Sloan Digital Sky Survey Photometric System , 2001, astro-ph/0105401.

[54]  F. M. Maley,et al.  An Efficient Targeting Strategy for Multiobject Spectrograph Surveys: the Sloan Digital Sky Survey “Tiling” Algorithm , 2001, astro-ph/0105535.

[55]  V. Narayanan,et al.  Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Main Galaxy Sample , 2002, astro-ph/0206225.

[56]  V. Narayanan,et al.  Spectroscopic Target Selection for the Sloan Digital Sky Survey: The Luminous Red Galaxy Sample , 2001, astro-ph/0108153.

[57]  David Burstein,et al.  Old stellar populations. I. A spectroscopic comparison of galactic globular clusters, M 31 globular clusters, and elliptical galaxies. , 1984 .