Science with the Hubble Space Telescope -- II
Book Editors: P. Benvenuti, F. D. Macchetto, and E. J. Schreier
Electronic Editor: H. Payne

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HST Observations of the Luminous IRAS Source FSC10214+4724: A Gravitationally Lensed Infrared Quasar

Peter R. Eisenhardt
MS 169-327, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109

Lee Armus, David W. Hogg, B. T. Soifer, G. Neugebauer
Division of Physics, Math, & Astronomy, California Institute of Technology, Pasadena, CA 91125

Michael W. Werner
MS 169-327, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109

Abstract:

With a redshift of 2.3, the IRAS source FSC 10214+4724 is apparently one of the most luminous objects known in the Universe. We present an image of FSC10214+4724 at m obtained with the Hubble Space Telescope WFPC2 Planetary Camera. The source appears as an unresolved () arc long, with significant substructure along its length. The center of curvature of the arc is located near an elliptical galaxy to the north. An unresolved component 100 times fainter than the arc is clearly detected on the opposite side of this galaxy. The most straightforward interpretation is that FSC 10214+4724 is gravitationally lensed by the foreground elliptical galaxy, with the faint component a counterimage of the IRAS source. The brightness of the arc in the HST image is then magnified by and the intrinsic source diameter is pc) at m rest wavelength. The bolometric luminosity is probably amplified by a smaller factor (), due to the larger extent expected for the source in the far-infrared. A detailed lensing model is presented which reproduces the observed morphology and relative flux of the arc and counterimage, and correctly predicts the position angle of the lensing galaxy. The model also predicts reasonable values for the velocity dispersion, mass, and mass-to-light ratio of the lensing galaxy for a wide range of galaxy redshifts. A redshift for the lensing galaxy of is consistent with the measured surface brightness profile from the image, as well as with the galaxy's spectral energy distribution. The background lensed source has an intrinsic luminosity , and remains a highly luminous quasar with an extremely large ratio of infrared to optical/ultraviolet luminosity.

This work is fully described in Eisenhardt et al. (1996), Ap.J. Vol. 461, in press.

Acknowledgments:

This research was supported by NASA through a grant awarded by STScI, which is operated by AURA, Inc. under NASA contract NAS5-26555. Portions of the research described in this paper were carried out by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.

 
Figure: Lucy-Richardson deconvolution of WFPC2 Planetary Camera F814W image of IRAS FSC10214+4724. The field of view is approximately 10 arcseconds, and north is rotated 37 degrees counterclockwise from vertical, with east 90 degrees counterclockwise from north.