1. RRI Digital Repository
  2. 04. Astronomy and Astrophysics
  3. Research Papers (A&A)
Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/2750
Full metadata record
DC FieldValueLanguage
dc.contributor.authorWalker, R.C.-
dc.contributor.authorAnantharamaiah, K.R.-
dc.date.accessioned2007-06-12T06:08:11Z-
dc.date.available2007-06-12T06:08:11Z-
dc.date.issued2003-04-
dc.identifier.citationAstronomical Journal, 2003, Vol.125, p1756-1761en
dc.identifier.issn0004-6256-
dc.identifier.issn1538-3881 (online)-
dc.identifier.urihttp://hdl.handle.net/2289/2750-
dc.descriptionOpen Accessen
dc.description.abstractThe radio source 3C 84 in NGC 1275 has a two-sided structure on parsec scales. The northern feature, presumed to be associated with a jet moving away from Earth, shows strong evidence for free-free absorption. The ionized gas responsible for that absorption would be a source of detectable stimulated recombination line emission for a wide range of physical conditions. The VLBA has been used to search for the H65α hydrogen recombination line. The line is expected to be seen only against the northern feature, which contains a small fraction of the total radio flux density. This spatial discrimination significantly aids the search for a weak line. No line was seen, with upper limits of roughly 15% of the continuum over a velocity range of 1486 km s-1 with resolutions up to 6.6 km s-1. In the absence of a strong radiation field, this would imply that the free-free absorbing gas has a wide velocity width, is moving rapidly relative to the systemic velocity, or is concentrated in a thin high-density structure. All these possibilities are reasonably likely close to an active galactic nucleus (AGN). However, in the intense radiation environment of the AGN, even considering only the radiation we actually observe passing through the free-free absorbing gas, the nondetection is probably ensured by a combination of saturation and radiation damping.en
dc.format.extent656656 bytes-
dc.format.mimetypeapplication/pdf-
dc.language.isoenen
dc.publisherThe University of Chicago Press for the American Astronomical Societyen
dc.relation.urihttp://adsabs.harvard.edu/cgi-bin/bib_query?2003AJ....125.1756Wen
dc.relation.urihttp://arxiv.org/abs/astro-ph/0212430en
dc.relation.urihttp://dx.doi.org/10.1086/368145en
dc.rights2003 American Astronomical Societyen
dc.subjectGalaxies: Activeen
dc.subjectGalaxies: Individual: NGC Number: NGC 1275en
dc.subjectGalaxies: Jetsen
dc.subjectRadio Emission Linesen
dc.subjectTechniques: Image Processingen
dc.titleA VLBA Search for a Stimulated Recombination Line from the Accretion Region in NGC 1275en
dc.typeArticleen
Appears in Collections:Research Papers (A&A)

Files in This Item:
File Description SizeFormat 
2003 AJ V125 p1756.pdfOpen Access641.27 kBAdobe PDFView/Open
Show simple item record


Items in RRI Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.