A Caltech Library Service

Gas and Dust in Ultraluminous Galactic Nuclei

Scoville, N. Z. and Yun, M. S. (1999) Gas and Dust in Ultraluminous Galactic Nuclei. In: Galaxy Interactions at Low and High Redshift. International Astronomical Union Symposium (IAUS). No.186. Springer , Dordrecht, pp. 265-272. ISBN 978-0-7923-5833-6.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


Millimeter-wave interferometry has clearly shown the existence of enormous masses (10^9 – 10^(10) M⨀) of molecular gas concentrated in the nuclear regions (R < 500 pc) of many luminous and ultraluminous infrared galaxies. In these systems, molecular gas is an obvious source of fuel for nuclear starbursts and active galactic nuclei (AGN). In several ultraluminous systems (e.g., Arp 220 and Mrk 231), there now exists CO (2-1) interferometry at < 1″ resolution which reveals for the first time extremely dense, gaseous accretion disks on the scale 50–300 pc. Based on the low velocity dispersion of the molecular gas in the nuclear disks, we believe them to be extremely thin (10–50 pc). In addition, high brightness temperatures in the CO lines (10–20 K) imply that these disks are nearly uniformly filled with a continuous gas distribution, rather than being relatively isolated, self-gravitating GMCs. Although the gas is ‘uniformly’ distributed, the gas densities must be high, > 10^4 cm^(-3). When viewed near the plane of the disk, the central AGNs, if they exist, will be totally obscured at optical and near infrared wavelengths. In Mrk 231, our line of sight is probably within 60° of the disk axis, but in Arp 220 the disk is closer to edge-on. In fact, recent near infrared imaging of Arp 220 with the NICMOS camera on the HST reveals totally opaque dust disks embedded within the central star clusters of both nuclei.

Item Type:Book Section
Related URLs:
URLURL TypeDescription ReadCube access
Scoville, N. Z.0000-0002-0438-3323
Yun, M. S.0000-0001-7095-7543
Additional Information:© 1999 Springer Science+Business Media Dordrecht. This research is supported in part by NSF Grant AST96-13717 and the Norris Planetary Origins Project. We thank Nanci Candelin for help in preparation of this manuscript.
Funding AgencyGrant Number
NSFAST 96-13717
Norris Planetary Origins ProjectUNSPECIFIED
Subject Keywords:Brightness Temperature; Active Galactic Nucleus; High Brightness Temperature; Double Nucleus; Nuclear Disk
Series Name:International Astronomical Union Symposium (IAUS)
Issue or Number:186
Record Number:CaltechAUTHORS:20190605-160848889
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96176
Deposited By: Tony Diaz
Deposited On:06 Jun 2019 03:05
Last Modified:16 Nov 2021 17:18

Repository Staff Only: item control page