Sign on

SAO/NASA ADS Astronomy Abstract Service


· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (30) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (1)
· NED Objects (1)
· Reads History
·
· Translate This Page
Title:
Radiative excitation of molecules near powerful compact radio sources
Authors:
Maloney, Philip R.; Begelman, Mitchell C.; Rees, Martin J.
Affiliation:
AA(University of Colorado, Boulder, CO, US), AB(University of Colorado, Boulder, CO, US), AC(Institute of Astronomy, Cambridge, UK)
Publication:
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 432, no. 2, p. 606-611 (ApJ Homepage)
Publication Date:
09/1994
Category:
Astrophysics
Origin:
STI
NASA/STI Keywords:
Active Galactic Nuclei, Emission Spectra, Gas Heating, Interstellar Matter, Molecular Excitation, Radio Emission, Radio Galaxies, Brightness Temperature, Carbon Monoxide, Rotational States, Toruses
DOI:
10.1086/174599
Bibliographic Code:
1994ApJ...432..606M

Abstract

In a recent paper, Barvainis & Antonucci searched for and failed to detect CO J = 1 goes to 0 absorption from the obscuring torus in the nearby powerful radio galaxy Cygnus A. We show that a plausible explanation for the lack of absorption (assuming that the ionization parameter within the torus is low enough for the gas to be molecular) is that radiative excitation of the CO molecules by the nonthermal radio continuum increases the excitation temperature of the lower rotational levels substantially, reducing the optical depths. The excitation temperature may approach the brightness temperature of the radio source at high enough flux-to-density ratios. Heating of the gas by the nonthermal excitation may also be important. We discuss the region of parameter space in which this excitation mechanism will be important and the implications for observations of obscuring tori.

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences



More Article Retrieval Options

HELP for Article Retrieval


Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

  New!

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints