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The unusual near-infrared morphology of the radio-loud quasar 4C + 09.17

Armus, L. and Neugebauer, G. and Lehnert, M. D. and Matthews, K. (1997) The unusual near-infrared morphology of the radio-loud quasar 4C + 09.17. Monthly Notices of the Royal Astronomical Society, 289 (3). pp. 621-628. ISSN 0035-8711. doi:10.1093/mnras/289.3.621.

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Near-infrared images of the luminous, high-redshift (z= 2.1108), radio-loud quasar 4C + 09.17 reveal a complex structure. The quasar (K= 15.76 mag) is surrounded by three ‘companion’ objects having 17.9 <K< 20.2 mag at radii of 1.7 < Δr< 2.9 arcsec, as well as bright, diffuse emission. The brightest companion has a redshift of z = 0.8384 (Lehnert & Becker), and its optical-infrared colours (Lehnert et al.) are consistent with a late-type spiral galaxy at this redshift with a luminosity of about 2L^⋆. This object is probably the galaxy responsible for the strongest MgII absorption-line system seen in the spectrum of 4C + 09.17 by Barthel et al. Redshifts are not available for the remaining two companions. The red colours of the second brightest companion appear most consistent with a high-redshift star-forming galaxy atz > 1.5. If this object is at the redshift of 4C + 09.17, it has a luminosity of about 7L^⋆. The faintest companion has colours which are unlike those expected from either a spiral or an E/S0 galaxy at any redshift associated with the 4C +09.17 system. Since this object lies along the same direction as the radio jet/lobe of 4C + 09.17, as well as the extended Lyα emission mapped by Heckman et al., we suggest that this component can be explained as a combination of strong line emission and scattered QSO light. The resolved, diffuse emission surrounding 4C + 09.17 is bright, K~ 17.0 mag, and about 1 mag redder inJ—K than the quasar. If this emission is starlight, a very luminous elliptical host galaxy is implied for 4C +09.17. Scattered and reddened AGN light, emission-line gas, and flux from absorbing galaxies along the line of sight may all contribute to this emission.

Item Type:Article
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URLURL TypeDescription Paper
Armus, L.0000-0003-3498-2973
Lehnert, M. D.0000-0003-1939-5885
Additional Information:© 1997 RAS. Accepted 1997 March 21. Received 1997 February 6; in original form 1996 October 7. This work was based on observations made with the W. M. Keck Observatory, which is operated as a scientific partnership between the California Institute of Technology and the University of California. We thank the entire Keck staff, especially Wendy Harrison and Al Conrad, for making these observations possible. We also thank Peter Barthel, Tim Heckman, David Hogg, Neill Reid, Tom Soifer and Chuck Steidel for helpful discussions. Finally, we thank Steve Warren, the referee, whose comments and suggestions helped to improve the final version of this paper. Infrared astrophysics at Caltech is supported by grants from NASA. This research has made use of the NASA/IPAC Extragalactic Database, which is operated by the Jet Propulsion Laboratory, Caltech, under contract with NASA.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:galaxies: photometry, quasars: general, quasars: individual: 4C + 09.17, infrared: galaxies
Issue or Number:3
Record Number:CaltechAUTHORS:20170210-142343859
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Official Citation:L. Annus, G. Neugebauer, M. D. Lehnert, K. Matthews; The unusual near-infrared morphology of the radio-loud quasar 4C + 09.17. Mon Not R Astron Soc 1997; 289 (3): 621-628. doi: 10.1093/mnras/289.3.621
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:74216
Deposited By: Ruth Sustaita
Deposited On:11 Feb 2017 01:23
Last Modified:11 Nov 2021 05:25

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