A Caltech Library Service

Cosmic Evolution of Star Formation in Type-1 Quasar Hosts Since z = 1

Shi, Yong and Rieke, George H. and Ogle, Patrick and Jiang, Linhua and Diamond-Stanic, Aleksandar M. (2009) Cosmic Evolution of Star Formation in Type-1 Quasar Hosts Since z = 1. Astrophysical Journal, 703 (1). pp. 1107-1122. ISSN 0004-637X.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


We present Spitzer Infrared Spectrograph observations of a complete sample of 57 Sloan Digital Sky Survey type-1 quasars at z ~ 1. Aromatic features at 6.2 and/or 7.7 μm are detected in about half of the sample and show profiles similar to those seen in normal galaxies at both low and high redshift, indicating a star formation origin for the features. Based on the ratio of aromatic to star formation infrared (SFIR) luminosities for normal star-forming galaxies at z ~ 1, we have constructed the SFIR luminosity function (LF) of z ~ 1 quasars. As we found earlier for low-redshift Palomar-Green (PG) quasars, these z ~ 1 quasars show a flatter SFIR LF than do z ~ 1 field galaxies, implying the quasar host galaxy population has on average a higher star formation rate (SFR) than the field galaxies do. As measured from their SFIR LF, individual quasar hosts have on average LIRG-level SFRs, which mainly arise in the circumnuclear regions. By comparing with similar measurements of low-redshift PG quasars, we find that the comoving SFIR luminosity density in quasar hosts shows a much larger increase with redshift than that in field galaxies. The behavior is consistent with pure density evolution since the average SFR and the average SFR/BH accretion rate in quasar hosts show little evolution with redshift. For individual quasars, we have found a correlation between the aromatic-based SFR and the luminosity of the nuclear radiation, consistent with predictions of some theoretical models. We propose that type-1 quasars reside in a distinct galaxy population that shows elliptical morphology but that harbors a significant fraction of intermediate-age stars and is experiencing intense circumnuclear star formation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Shi, Yong0000-0002-8614-6275
Rieke, George H.0000-0003-2303-6519
Ogle, Patrick0000-0002-3471-981X
Jiang, Linhua0000-0003-4176-6486
Additional Information:© 2009 American Astronomical Society. Print publication: Issue 1 (2009 September 20); received 2009 May 4; accepted for publication 2009 August 6; published 2009 September 4. We thank the anonymous referee for the detailed and constructive comments. We also thank Jane Rigby and Dean Hines for careful reading and comments. Support for this work was provided by NASA through contract 1255094 issued by JPL/ California Institute of Technology.
Funding AgencyGrant Number
Subject Keywords:galaxies: active; galaxies: nuclei; galaxies: starburst
Issue or Number:1
Record Number:CaltechAUTHORS:20090929-110848426
Persistent URL:
Official Citation:Cosmic Evolution of Star Formation in Type-1 Quasar Hosts Since z = 1 Yong Shi, George H. Rieke, Patrick Ogle, Linhua Jiang, and Aleksandar M. Diamond-Stanic 2009 ApJ 703 1107-1122 doi: 10.1088/0004-637X/703/1/1107
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16110
Deposited By: Jason Perez
Deposited On:02 Oct 2009 21:51
Last Modified:09 Mar 2020 13:19

Repository Staff Only: item control page