Ultracompact H II regions studies. II. Virtual Observatory Resource

Authors
  1. Walsh A.J.
  2. Burton M.G.
  3. Hyland A.R.
  4. Robinson G.
  5. Published by
    CDS
Abstract

High spatial resolution radio continuum and 6.67-GHz methanol spectral line data are presented for methanol masers previously detected by Walsh et al. (1997, Cat. <J/MNRAS/291/261>). Methanol maser and/or radio continuum emission is found in 364 cases towards IRAS-selected regions. For those sources with methanol maser emission, relative positions have been obtained to an accuracy of typically 0.05arcsec, with absolute positions accurate to around 1arcsec. Maps of selected sources are provided. The intensity of the maser emission does not seem to depend on the presence of a continuum source. The coincidence of water and methanol maser positions in some regions suggests there is overlap in the requirements for methanol and water maser emission to be observable. However, there is a striking difference between the general proximity of methanol and water masers to both cometary and irregularly shaped ultracompact (UC) HII regions, indicating that, in other cases, there must be differing environments conductive to stimulating their emission. We show that the methanol maser is most likely present before an observable UC HII region is formed around a massive star and is quickly destroyed as the UC HII region evolves. There are 36 out of 97 maser sites that are linearly extended. The hypothesis that the maser emission is found in a circumstellar disc is not inconsistent with these 36 maser sites, but is unlikely. It cannot, however, account for all other maser sites. An alternative model which uses shocks to create the masing spots can more readily reproduce the maser spot distributions.

Keywords
  1. h-ii-regions
  2. astrophysical-masers
  3. radio-astronomy
  4. radial-velocity
Bibliographic source Bibcode
1998MNRAS.301..640W
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/301/640
IVOA Identifier IVOID
ivo://CDS.VizieR/J/MNRAS/301/640
Document Object Identifer DOI
doi:10.26093/cds/vizier.73010640

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/301/640
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/301/640
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/301/640
IVOA Table Access TAP
http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
http://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/301/640/table2?
https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/301/640/table2?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/301/640/table2?

History

2000-02-21T21:47:44Z
Resource record created
2000-02-21T21:47:44Z
Created
2024-06-25T20:18:18Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr