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The AGN content of ultraluminous IR galaxies: High resolution VLA imaging of the IRAS 1 Jy ULIRG sample

Nagar, N. M. and Wilson, A. S. and Falcke, H. and Veilleux, S. and Maiolino, R. (2003) The AGN content of ultraluminous IR galaxies: High resolution VLA imaging of the IRAS 1 Jy ULIRG sample. Astronomy & Astrophysics, 409 (1). pp. 115-121. ISSN 0004-6361. doi:10.1051/0004-6361:20031069.

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This paper presents the results of a high resolution radio imaging survey of 83 of the 118 ultraluminous infrared galaxies (ULIRGs) in the IRAS 1 Jy ULIRG sample. We have observed these ULIRGs at 15 GHz with the Very Large Array (VLA). We find that ~75% of Seyferts (both type 1 and 2) and LINERs have radio nuclei which are compact at our 150 mas resolution. The detection rate of H II nuclei is significantly lower (32%); the detections among these are preferentially H II + LINER/Seyfert composite nuclei. Among ULIRGs with multiple optical or near-IR nuclei our observations detected only one (or no) nucleus; in these the radio detection is typically towards the brightest near-IR nucleus. The compactness of the radio sources, the higher detection rates in AGN-type nuclei than H II nuclei, the preferential detection of nuclei with unresolved point sources in the near-IR, the low soft X-ray to nuclear radio luminosity ratio (arguing against thermal emission powering the radio nuclei), and the lack of correlation between radio power and Hα luminosity, all support an origin of the detected radio nuclei in AGN related activity. This result is especially interesting for LINER ULIRGs for which signatures of AGNs have often been ambiguous in other wavebands. Such a high incidence of AGN would provide, for the first time, a large sample in which to study the interplay between AGN, starbursts, and galaxy mergers.

Item Type:Article
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URLURL TypeDescription Paper
Nagar, N. M.0000-0001-6920-662X
Veilleux, S.0000-0002-3158-6820
Additional Information:© 2003 ESO. Received: 17 April 2003. Accepted: 7 July 2003. This work was partially supported by the Italian Ministry for University and Research (MURST) under grant Cofin00-02-36 and the Italian Space Agency (ASI) under grant 1/R/27/00. This research was supported in part by NASA through grant NAG81755 to the University of Maryland. NN thanks the Raman Research Institute for hospitality during the writing of a part of this paper. SV thanks the California Institute of Technology and the Observatories of the Carnegie Institution for their hospitality.
Funding AgencyGrant Number
Ministero dell'università e della ricerca scientifica e tecnologica (MURST)Cofin00-02-36
Agenzia Spaziale Italiana (ASI)1/R/27/00
Subject Keywords:accretion, accretion disks - galaxies: active - galaxies: jets - radio continuum: galaxies - surveys
Issue or Number:1
Record Number:CaltechAUTHORS:20180306-131029238
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Official Citation:The AGN content of ultraluminous IR galaxies: High resolution VLA imaging of the IRAS 1 Jy ULIRG sample N. M. Nagar, A. S. Wilson, H. Falcke, S. Veilleux and R. Maiolino A&A, 409 1 (2003) 115-121 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85138
Deposited By: Ruth Sustaita
Deposited On:06 Mar 2018 21:56
Last Modified:15 Nov 2021 20:26

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