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Published June 1, 2000 | Published + Accepted Version
Journal Article Open

APM 08279+5255: Keck Near‐ and Mid‐Infrared High‐Resolution Imaging


We present Keck high-resolution near-IR (2.2 μm; FWHM ~ 0."15) and mid-IR (12.5 μm; FWHM ~ 0."4) images of APM 08279+5255, a z = 3.91 IR-luminous broad absorption line quasi-stellar object with a prodigious apparent bolometric luminosity of 5 × 10^(15) L_☉, the largest known in the universe. The K-band image shows that this system consists of three components, all of which are likely to be the gravitationally lensed images of the same background object, and the 12.5 μm image shows a morphology consistent with such an image configuration. Our lens model suggests that the magnification factor is ~100 from the rest-frame UV to mid-IR, where most of the luminosity is released. The intrinsic bolometric luminosity and IR luminosity of APM 08279+5255 are estimated to be 5 × 10^(13) L_☉ and 1 × 10^(13) L_☉, respectively. This indicates that APM 08279+5255 is intrinsically luminous, but it is not the most luminous object known. As for its dust contents, little can be determined with the currently available data because of the uncertainties associated with the dust emissivity and the possible effect of differential magnification. We also suggest that the lensing galaxy is likely to be a massive galaxy at z ~ 3.

Additional Information

© 2000 American Astronomical Society. Received 1999 June 10. Accepted 2000 January 20. We thank R. A. Ibata and G. F. Lewis for communicating to us their results prior to the submission of their paper. E. E. thanks Chris Fassnacht and Andrew Blain for helpful discussions. The W. M. Keck Observatory is operated as a scientific partnership between the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. It was made possible by the generous financial support of the W. M. Keck Foundation. Infrared astronomy at Caltech is supported by grants from the NSF and NASA. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

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Published - Egami_2000_ApJ_535_561.pdf

Accepted Version - 0001200.pdf


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