EDP Sciences
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Volume 365, Number 3, January III 2001
Page(s) 409 - 416
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20000508

A&A 365, 409-416 (2001)
DOI: 10.1051/0004-6361:20000508

ISO continuum observations of quasars at z=1-4

I. Spectral energy distributions of quasars from the UV to far-infrared
S. Oyabu1, K. Kawara1, Y. Tsuzuki1, Y. Sofue1, Y. Sato1, H. Okuda2, 3, Y. Taniguchi4, H. Shibai5, C. Gabriel6, T. Hasegawa3 and E. Nishihara3

1  Institute of Astronomy, The University of Tokyo, 2-21-1 Osawa Mitaka, Tokyo 181-0015, Japan
2  Institute of Space and Astronautical Science (ISAS), 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan
3  Gunma Astronomical Observatory, 6860-86 Nakayama, Takayama, Agatsuma, Gunma 371-0702, Japan
4  Astronomical Institute, Tohoku University, Aoba, Sendai 980-8578, Japan
5  Department of Astrophysics, School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
6  ISO Data Centre, Astrophysics Division of ESA, Villafranca, 28080 Madrid, Spain

(Received 10 August 2000 / Accepted 24 October 2000 )

Eight luminous quasars with -30 < MB < -27 at z = 1.4-3.7 have been observed in the mid- and far-infrared using ISO. All the quasars have been detected in the mid-infrared bands of ISOCAM, while no far-infrared detections have been made with ISOPHOT. SEDs (Spectral Energy Distributions) from the UV to far-infrared have been obtained while supplementing ISO observations with photometry in the optical and near-infrared made from the ground within 17 months. The SEDs are compared with the MED (Mean spectral Energy Distributions) of low-redshift quasars with -27 < MB < -22. It is shown that our far-infrared observations were limited by confusion noise due to crowded sources.

Key words: infrared: galaxies -- infrared: ISM: continuum -- quasars: general -- galaxies: photometry

Offprint request: S. Oyabu, shinki@mtk.ioa.s.u-tokyo.ac.jp

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