The detection of silicate emission from quasars at 10 and 18 microns

L Hao; HWW Spoon; GC Sloan; JA Marshall; L Armus; A. G. G. M. Tielens; B Sargent; IM van Bemmel; V. Charmandaris; DW Weedman; J. R. Houck

doi:10.1086/431227

The detection of silicate emission from quasars at 10 and 18 microns

L Hao^*, HWW Spoon, GC Sloan, JA Marshall, L Armus, A. G. G. M. Tielens, B Sargent, IM van Bemmel, V. Charmandaris, DW Weedman, J. R. Houck

^*Corresponding author for this work

Research output: Contribution to journal › Article › Academic › peer-review

163 Citations (Scopus)

Abstract

We report the spectroscopic detection of silicate emission at 10 and 18 mm in five PG quasars, the first detection of these two features in galaxies outside the Local Group. This finding is consistent with the unification model for active galactic nuclei (AGNs), which predicts that an AGN torus seen pole-on should show a silicate emission feature in the mid-infrared. The strengths of the detected silicate emission features range from 0.12 to 1.25 times the continuum at 10 mu m and from 0.20 to 0.79 times the continuum at 18 mu m. The silicate grain temperatures inferred from the ratio of 18 mu m to 10 mm silicate features under the assumption of optically thin emission range from 140 to 220 K.

Original language	English
Pages (from-to)	L75-L78
Number of pages	4
Journal	Astrophysical Journal
Volume	625
Issue number	2
DOIs	https://doi.org/10.1086/431227
Publication status	Published - 1-Jun-2005

Keywords

galaxies : active
galaxies : ISM
infrared : galaxies
quasars : emission lines
ACTIVE GALACTIC NUCLEI
SPITZER-SPACE-TELESCOPE
ULTRALUMINOUS INFRARED GALAXIES
OBSCURING DUST TORI
SPECTROGRAPH IRS
DISTRIBUTIONS
CONTINUUM
SPECTRA
SPECTROSCOPY
EXTINCTION

Access to Document

10.1086/431227

Handle.net

Persistent link

Embargoed Document

The detection of silicate emission from quasars at 10 and 18 microns
Final publisher's version, 493 KB
Request copy

Cite this

@article{bac758f99d8b43228609e437492c92e6,

title = "The detection of silicate emission from quasars at 10 and 18 microns",

abstract = "We report the spectroscopic detection of silicate emission at 10 and 18 mm in five PG quasars, the first detection of these two features in galaxies outside the Local Group. This finding is consistent with the unification model for active galactic nuclei (AGNs), which predicts that an AGN torus seen pole-on should show a silicate emission feature in the mid-infrared. The strengths of the detected silicate emission features range from 0.12 to 1.25 times the continuum at 10 mu m and from 0.20 to 0.79 times the continuum at 18 mu m. The silicate grain temperatures inferred from the ratio of 18 mu m to 10 mm silicate features under the assumption of optically thin emission range from 140 to 220 K.",

keywords = "galaxies : active, galaxies : ISM, infrared : galaxies, quasars : emission lines, ACTIVE GALACTIC NUCLEI, SPITZER-SPACE-TELESCOPE, ULTRALUMINOUS INFRARED GALAXIES, OBSCURING DUST TORI, SPECTROGRAPH IRS, DISTRIBUTIONS, CONTINUUM, SPECTRA, SPECTROSCOPY, EXTINCTION",

author = "L Hao and HWW Spoon and GC Sloan and JA Marshall and L Armus and Tielens, {A. G. G. M.} and B Sargent and {van Bemmel}, IM and V. Charmandaris and DW Weedman and Houck, {J. R.}",

year = "2005",

month = jun,

day = "1",

doi = "10.1086/431227",

language = "English",

volume = "625",

pages = "L75--L78",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "IoP Publishing",

number = "2",

}

TY - JOUR

T1 - The detection of silicate emission from quasars at 10 and 18 microns

AU - Hao, L

AU - Spoon, HWW

AU - Sloan, GC

AU - Marshall, JA

AU - Armus, L

AU - Tielens, A. G. G. M.

AU - Sargent, B

AU - van Bemmel, IM

AU - Charmandaris, V.

AU - Weedman, DW

AU - Houck, J. R.

PY - 2005/6/1

Y1 - 2005/6/1

N2 - We report the spectroscopic detection of silicate emission at 10 and 18 mm in five PG quasars, the first detection of these two features in galaxies outside the Local Group. This finding is consistent with the unification model for active galactic nuclei (AGNs), which predicts that an AGN torus seen pole-on should show a silicate emission feature in the mid-infrared. The strengths of the detected silicate emission features range from 0.12 to 1.25 times the continuum at 10 mu m and from 0.20 to 0.79 times the continuum at 18 mu m. The silicate grain temperatures inferred from the ratio of 18 mu m to 10 mm silicate features under the assumption of optically thin emission range from 140 to 220 K.

AB - We report the spectroscopic detection of silicate emission at 10 and 18 mm in five PG quasars, the first detection of these two features in galaxies outside the Local Group. This finding is consistent with the unification model for active galactic nuclei (AGNs), which predicts that an AGN torus seen pole-on should show a silicate emission feature in the mid-infrared. The strengths of the detected silicate emission features range from 0.12 to 1.25 times the continuum at 10 mu m and from 0.20 to 0.79 times the continuum at 18 mu m. The silicate grain temperatures inferred from the ratio of 18 mu m to 10 mm silicate features under the assumption of optically thin emission range from 140 to 220 K.

KW - galaxies : active

KW - galaxies : ISM

KW - infrared : galaxies

KW - quasars : emission lines

KW - ACTIVE GALACTIC NUCLEI

KW - SPITZER-SPACE-TELESCOPE

KW - ULTRALUMINOUS INFRARED GALAXIES

KW - OBSCURING DUST TORI

KW - SPECTROGRAPH IRS

KW - DISTRIBUTIONS

KW - CONTINUUM

KW - SPECTRA

KW - SPECTROSCOPY

KW - EXTINCTION

U2 - 10.1086/431227

DO - 10.1086/431227

M3 - Article

SN - 0004-637X

VL - 625

SP - L75-L78

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

ER -

The detection of silicate emission from quasars at 10 and 18 microns

Abstract

Keywords

Access to Document

Handle.net

Embargoed Document

Fingerprint

Cite this