TY - JOUR
T1 - Average spectra of massive galaxies in the Sloan Digital Sky Survey
AU - Eisenstein, Daniel J.
AU - Hogg, David W.
AU - Fukugita, Masataka
AU - Nakamura, Osamu
AU - Bernardi, Mariangela
AU - Finkbeiner, Douglas P.
AU - Schlegel, David J.
AU - Brinkmann, J.
AU - Connolly, Andrew J.
AU - Csabai, István
AU - Gunn, James E.
AU - Ivezić, Željko
AU - Lamb, Don Q.
AU - Loveday, Jon
AU - Munn, Jeffrey A.
AU - Nicol, Robert C.
AU - Schneider, Donald P.
AU - Strauss, Michael A.
AU - Szalay, Alex
AU - York, Don G.
PY - 2003/3/10
Y1 - 2003/3/10
N2 - We combine Sloan Digital Sky Survey spectra of 22,000 luminous, red, bulge-dominated galaxies to get high signal-to-noise ratio average spectra in the rest-frame optical and ultraviolet (2600-7000 A). The average spectra of these massive, quiescent galaxies are early type with weak emission lines and with absorption lines indicating an apparent excess of α-elements over solar abundance ratios. We make average spectra of subsamples selected by luminosity, environment, and redshift. The average spectra are remarkable in their similarity. What variations do exist in the average spectra as a function of luminosity and environment are found to form a nearly one-parameter family in spectrum space. We present a high signal-to-noise ratio spectrum of the variation. We measure the properties of the variation with a modified version of the Lick index system and compare to model spectra from stellar population syntheses. The variation may be a combination of age and chemical abundance differences, but the conservative conclusion is that the quality of the data considerably exceeds the current state of the models.
AB - We combine Sloan Digital Sky Survey spectra of 22,000 luminous, red, bulge-dominated galaxies to get high signal-to-noise ratio average spectra in the rest-frame optical and ultraviolet (2600-7000 A). The average spectra of these massive, quiescent galaxies are early type with weak emission lines and with absorption lines indicating an apparent excess of α-elements over solar abundance ratios. We make average spectra of subsamples selected by luminosity, environment, and redshift. The average spectra are remarkable in their similarity. What variations do exist in the average spectra as a function of luminosity and environment are found to form a nearly one-parameter family in spectrum space. We present a high signal-to-noise ratio spectrum of the variation. We measure the properties of the variation with a modified version of the Lick index system and compare to model spectra from stellar population syntheses. The variation may be a combination of age and chemical abundance differences, but the conservative conclusion is that the quality of the data considerably exceeds the current state of the models.
KW - Cosmology: observations
KW - Galaxies: abundances
KW - Galaxies: clusters: general
KW - Galaxies: elliptical and lenticular, cD
KW - Galaxies: evolution
KW - Methods: statistical
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U2 - 10.1086/346233
DO - 10.1086/346233
M3 - Review article
AN - SCOPUS:0041761667
SN - 0004-637X
VL - 585
SP - 694
EP - 713
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2 I
ER -