Issue |
A&A
Volume 410, Number 1, October IV 2003
|
|
---|---|---|
Page(s) | 75 - 82 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20031201 | |
Published online | 17 November 2003 |
The near-IR properties and continuum shapes of high redshift quasars from the Sloan Digital Sky Survey
1
Max-Planck-Institut fur Astronomie, Konigstuhl 17, 69117, Heidelberg, Germany
2
Instituto de Astrofisica de Canarias, 38205 La Laguna, Tenerife, Spain
3
Steward Observatory, The University of Arizona 933 N. Cherry Ave, Tucson, AZ 85721-0065 Arizona, USA
4
Princeton University Observatory, Princeton 08544, USA
5
Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
6
Apache Point Observatory PO Box 59, Sunspot, NM 88349-0059, USA
Corresponding author: L. Pentericci, laura@mpia.de
Received:
22
January
2003
Accepted:
4
July
2003
We present photometry for a sample of 45 high redshift
quasars found by the Sloan Digital Sky Survey.
The sample was originally selected on the basis of optical
colors and spans a redshift range from 3.6 to 5.03. Our photometry reflects the rest-frame SED longward of Lyα for all redshifts.
The results show that the near-IR colors
of high redshift quasars are quite uniform.
We have modelled the continuum shape of the quasars (from just
beyond to ~4000 Å) with a power law of the form
, and find
with a scatter of 0.33. This value is similar to what is
found for lower redshift quasars over the same restframe
wavelength range, and we conclude that there is hardly any
evolution in the continuum properties of optically selected
quasars up to redshift 5. The spectral indices found by combining
near-IR with optical photometry are in general consistent but
slightly flatter than what is found for the same quasars using
the optical spectra and photometry alone, showing that the
continuum region used to determine the spectral indices can
somewhat influence the results.
Key words: galaxies: active / quasars: general / infrared: general / cosmology: observations
© ESO, 2003
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