作者
Daniel E Vanden Berk, Gordon T Richards, Amanda Bauer, Michael A Strauss, Donald P Schneider, Timothy M Heckman, Donald G York, Patrick B Hall, Xiaohui Fan, GR Knapp, Scott F Anderson, James Annis, Neta A Bahcall, Mariangela Bernardi, John W Briggs, J Brinkmann, Robert Brunner, Scott Burles, Larry Carey, Francisco J Castander, AJ Connolly, JH Crocker, Istvan Csabai, Mamoru Doi, Douglas Finkbeiner, Scott Friedman, Joshua A Frieman, Masataka Fukugita, James E Gunn, GS Hennessy, Željko Ivezić, Stephen Kent, Peter Z Kunszt, DQ Lamb, R French Leger, Daniel C Long, Jon Loveday, Robert H Lupton, Avery Meiksin, Aronne Merelli, Jeffrey A Munn, Heidi Jo Newberg, Matt Newcomb, RC Nichol, Russell Owen, Jeffrey R Pier, Adrian Pope, Constance M Rockosi, David J Schlegel, Walter A Siegmund, Stephen Smee, Yehuda Snir, Chris Stoughton, Christopher Stubbs, Mark SubbaRao, Alexander S Szalay, Gyula P Szokoly, Christy Tremonti, Alan Uomoto, Patrick Waddell, Brian Yanny, Wei Zheng
发表日期
2001/8/1
期刊
The Astronomical Journal
卷号
122
期号
2
页码范围
549
出版商
IOP Publishing
简介
We have created a variety of composite quasar spectra using a homogeneous data set of over 2200 spectra from the Sloan Digital Sky Survey (SDSS). The quasar sample spans a redshift range of 0.044≤ z≤ 4.789 and an absolute r′ magnitude range of-18.0 to-26.5. The input spectra cover an observed wavelength range of 3800–9200 Å at a resolution of 1800. The median composite covers a rest-wavelength range from 800 to 8555 Å and reaches a peak signal-to-noise ratio of over 300 per 1 Å resolution element in the rest frame. We have identified over 80 emission-line features in the spectrum. Emission-line shifts relative to nominal laboratory wavelengths are seen for many of the ionic species. Peak shifts of the broad permitted and semiforbidden lines are strongly correlated with ionization energy, as previously suggested, but we find that the narrow forbidden lines are also shifted by amounts that are …
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DEV Berk, GT Richards, A Bauer, MA Strauss… - The Astronomical Journal, 2001