8th HEAD Meeting, 8-11 September, 2004
Session 30 VERITAS Workshop
Oral, Friday, September 10, 2004, 4:00-6:00pm

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[30.03] Radio Observations of VERITAS Sources: Imaging the Parsec-Scale Jets

B.G. Piner (Whittier College)

VLBI observations currently provide the only means of producing images of the parsec-scale jets of extragalactic TeV gamma-ray sources on scales approaching the gamma-ray production scales. We will review radio observations of TeV gamma-ray sources, with an emphasis on VLBI observations from the NRAO Very Long Baseline Array (VLBA). We have used VLBA monitoring observations of Markarian 421, Markarian 501, 1ES 2344+514, PKS 2155-304, and 1ES 1959+650 to measure the apparent jet speeds for all of these sources. The apparent speeds of the parsec-scale jets of the TeV sources are considerably slower than typical gamma-ray blazar apparent speeds, suggestive of a rapid loss of bulk kinetic energy close to the core. Observations of limb brightening in the jet of Mkn 501 by Giroletti et al. imply that these jets may have velocity structures transverse to the jets as well. We will also present our dual-circular polarization VLBA observations of Mkn 421 made for one year following the gamma-ray high state of early 2001, along with more recent VLBA observations of Markarian 421, PKS 2155-304, 1ES 1959+650, and 1ES 1426+428 from 2003 and 2004. The expected capabilities of radio telescopes during the VERITAS epoch and technical/organizational issues regarding radio observations will also be discussed.

This material is based upon work supported by the National Science Foundation under Grant No. 0305475 and by a Cottrell College Science Award from Research Corporation.

If you would like more information about this abstract, please follow the link to web.whittier.edu/gpiner/research/index.htm. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: gpiner@whittier.edu

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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.