Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Reads History
·
· Translate This Page
Title:
Filtering AGNs from Starbursts in Deep VLBA+GBT Fields
Authors:
Wrobel, J. M.; Garrett, M. A.; Morganti, R.
Affiliation:
AA(NRAO), AB(JIVE), AC(ASTRON)
Publication:
American Astronomical Society, 201st AAS Meeting, #78.12; Bulletin of the American Astronomical Society, Vol. 34, p.1233
Publication Date:
12/2002
Origin:
AAS
Bibliographic Code:
2002AAS...201.7812W

Abstract

For starbursts, free-free absorption limits the total brightness temperature Tb of the coextensive thermal and nonthermal radio emission to a few times the electron temperature of about 104 K (Condon, 1992, ARAA, 30, 575). For active galactic nuclei (AGNs), higher brightness temperatures are reached. Sky patches can be filtered for AGN with Tb > 2 x 105 K through deep observations at a frequency ν = 1.4 GHz with the NRAO VLBA and GBT. Such filtering observations were recently made, within a patch of the NDWFS Boötes field known from WSRT images to be densely populated with faint radio sources (de Vries et al. 2002, AJ, 123, 1784; Morganti & Garrett, 2002, ASTRON Newsletter, No. 17). Any WSRT source that is also detected with the VLBA+GBT cannot be energized by just a starburst. Analysis of the VLBA+GBT data is in progress. Phase referencing to the in-beam calibrator WSRT J142910+352945 yields an rms sensitivity of 9 μ Jy beam-1 and, so far, two clear detections. One is of a 400-μ Jy source coincident with WSRT J142934+352858. This AGN is hosted by a candidate high-redshift galaxy, as inferred from the host's apparent drop-out in the BW band of the NDWFS. The other detection locates the 300-μ Jy AGN embedded in WSRT J142923+352851. Both detections are astrometrically anchored to the ICRF. This work made use of images provided by the NDWFS (Jannuzi & Dey, 1999, ASP Conference Series, 191, 111), which is supported by NOAO. NOAO is operated by AURA, Inc., under a cooperative agreement with the NSF. NRAO is a facility of the NSF operated under cooperative agreement by AUI.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints