@article {28087,
	title = {Average Spectra of Massive Galaxies in the Sloan Digital Sky Survey},
	journal = {The Astrophysical Journal},
	volume = {585},
	year = {2003},
	note = {n/a},
	month = {March 1, 2003},
	pages = {694-713},
	abstract = {We combine Sloan Digital Sky Survey spectra of 22,000 luminous, red,bulge-dominated galaxies to get high signal-to-noise ratio averagespectra in the rest-frame optical and ultraviolet (2600-7000 {\r A}).The average spectra of these massive, quiescent galaxies are early typewith weak emission lines and with absorption lines indicating anapparent excess of α-elements over solar abundance ratios. We makeaverage spectra of subsamples selected by luminosity, environment, andredshift. The average spectra are remarkable in their similarity. Whatvariations do exist in the average spectra as a function of luminosityand environment are found to form a nearly one-parameter family inspectrum space. We present a high signal-to-noise ratio spectrum of thevariation. We measure the properties of the variation with a modifiedversion of the Lick index system and compare to model spectra fromstellar population syntheses. The variation may be a combination of ageand chemical abundance differences, but the conservative conclusion isthat the quality of the data considerably exceeds the current state ofthe models.
},
	url = {http://adsabs.harvard.edu/abs/2003ApJ...585..694E},
	author = {Eisenstein, Daniel J. and Hogg, David W. and Fukugita, Masataka and Nakamura, Osamu and Bernardi, Mariangela and Finkbeiner, Douglas P. and Schlegel, David J. and Brinkmann, J. and Connolly, Andrew J. and Csabai, Istv{\'a}n and Gunn, James E. and Ivezi{\'c}, {\v Z}eljko and Lamb, Don Q. and Loveday, Jon and Munn, Jeffrey A. and Nichol, Robert C. and Schneider, Donald P. and Strauss, Michael A. and Szalay, Alex and York, Don G.}
}
