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Title: QUANTIFYING THE ANISOTROPY IN THE INFRARED EMISSION OF POWERFUL ACTIVE GALACTIC NUCLEI

Abstract

We use rest-frame near- and mid-IR data of an isotropically selected sample of quasars and radio galaxies at 1.0 {<=} z {<=} 1.4, which have been published previously by Leipski et al., to study the wavelength-dependent anisotropy of the IR emission. For that we build average spectral energy distributions of the quasar subsample (= type 1 AGNs) and radio galaxies (= type 2 AGNs) from {approx}1 to 17 {mu}m and plot the ratio of both average samples. From 2 to 8 {mu}m rest-frame wavelengths the ratio gradually decreases from 20 to 2 with values around 3 in the 10 {mu}m silicate feature. Longward of 12 {mu}m, the ratio decreases further and shows some high degree of isotropy at 15 {mu}m (ratio {approx}1.4). The results are consistent with upper limits derived from the X-ray/mid-IR correlation of local Seyfert galaxies. We find that the anisotropy in our high-luminosity radio-loud sample is smaller than in radio-quiet lower-luminosity active galactic nuclei (AGNs) which may be interpreted in the framework of a receding torus model with luminosity-dependent obscuration properties. It is also shown that the relatively small degree of anisotropy is consistent with clumpy torus models.

Authors:
;  [1];  [2];  [3]
  1. Department of Physics, University of California in Santa Barbara, Broida Hall, Santa Barbara, CA 93109 (United States)
  2. Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany)
  3. Astronomisches Institut RuhrUniversitaet Bochum, Universitaetsstr. 150, 44801 Bochum (Germany)
Publication Date:
OSTI Identifier:
21578344
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 736; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/736/1/26; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; EMISSION; ENERGY SPECTRA; GALAXY NUCLEI; INFRARED RADIATION; QUASARS; RADIO GALAXIES; SEYFERT GALAXIES; WAVELENGTHS; COSMIC RADIO SOURCES; ELECTROMAGNETIC RADIATION; GALAXIES; RADIATIONS; SPECTRA

Citation Formats

Hoenig, S. F., Antonucci, R., Leipski, C., and Haas, M., E-mail: shoenig@physics.ucsb.edu. QUANTIFYING THE ANISOTROPY IN THE INFRARED EMISSION OF POWERFUL ACTIVE GALACTIC NUCLEI. United States: N. p., 2011. Web. doi:10.1088/0004-637X/736/1/26.
Hoenig, S. F., Antonucci, R., Leipski, C., & Haas, M., E-mail: shoenig@physics.ucsb.edu. QUANTIFYING THE ANISOTROPY IN THE INFRARED EMISSION OF POWERFUL ACTIVE GALACTIC NUCLEI. United States. doi:10.1088/0004-637X/736/1/26.
Hoenig, S. F., Antonucci, R., Leipski, C., and Haas, M., E-mail: shoenig@physics.ucsb.edu. Wed . "QUANTIFYING THE ANISOTROPY IN THE INFRARED EMISSION OF POWERFUL ACTIVE GALACTIC NUCLEI". United States. doi:10.1088/0004-637X/736/1/26.
@article{osti_21578344,
title = {QUANTIFYING THE ANISOTROPY IN THE INFRARED EMISSION OF POWERFUL ACTIVE GALACTIC NUCLEI},
author = {Hoenig, S. F. and Antonucci, R. and Leipski, C. and Haas, M., E-mail: shoenig@physics.ucsb.edu},
abstractNote = {We use rest-frame near- and mid-IR data of an isotropically selected sample of quasars and radio galaxies at 1.0 {<=} z {<=} 1.4, which have been published previously by Leipski et al., to study the wavelength-dependent anisotropy of the IR emission. For that we build average spectral energy distributions of the quasar subsample (= type 1 AGNs) and radio galaxies (= type 2 AGNs) from {approx}1 to 17 {mu}m and plot the ratio of both average samples. From 2 to 8 {mu}m rest-frame wavelengths the ratio gradually decreases from 20 to 2 with values around 3 in the 10 {mu}m silicate feature. Longward of 12 {mu}m, the ratio decreases further and shows some high degree of isotropy at 15 {mu}m (ratio {approx}1.4). The results are consistent with upper limits derived from the X-ray/mid-IR correlation of local Seyfert galaxies. We find that the anisotropy in our high-luminosity radio-loud sample is smaller than in radio-quiet lower-luminosity active galactic nuclei (AGNs) which may be interpreted in the framework of a receding torus model with luminosity-dependent obscuration properties. It is also shown that the relatively small degree of anisotropy is consistent with clumpy torus models.},
doi = {10.1088/0004-637X/736/1/26},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 736,
place = {United States},
year = {2011},
month = {7}
}