Centiarcsecond Structure of Low Frequency Variable Extragalactic Sources

Details Centiarcsecond Structure of Low Frequency Variable Extragalactic Sources Centiarcsecond Structure of Low Frequency Variable Extragalactic Sources

Dec 1992

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992aas...181.4110t&link_type=abstract

American Astronomical Society, 181st AAS Meeting, #41.10; Bulletin of the American Astronomical Society, Vol. 24, p.1185

Astronomy and Astrophysics

Astronomy

Scientific paper

The distinction between an intrinsic nature of the variability of extragalactic sources and propagation phenomena remains problematic. The low frequency variability monitoring program has been underway at Arecibo Observatory since 1980. In this program 33 extragalactic sources taken from complete samples searched for variability at 318 MHz were monitored at bi--monthly intervals at five frequencies (1400, 880, 606, 430, and 318 MHz). Sixteen of the most active sources from the Arecibo low frequency monitoring program were selected for VLBI observations at 327 MHz to search for the structure on the scale of tens of milliarcseconds. The observations were carried out with the Global VLBI network stretching from Crimea (USSR) to Owens Valley (California) in March 1986. The resolution lost comparably to higher frequencies is counterbalanced by the typically larger angular size of structure patterns at lower frequencies. Propagation effects are also more noticeable at longer wavelengths, as the degree of scattering of radiation in an ionized medium is proportional to the square of the wavelength. As a general statement we note, that the data show clear evidences of significant scattering at baselines 2 -- 6 Mlambda and longer. We present here VLBI maps at 327 MHz of 9 sources: 0116+319 (4C31.04), 0235+164, 0333+321 (NRAO 140), 0735+178, 1055+018, 1117+146 (4C14.41), 1611+343 (DA406), 1633+382 (4C38.41), 1901+319 (3C395). These maps are utilized both for search of intrinsic properties of sources (in particular, comparing with VLBI maps at higher frequencies) and for investigations of propagation phenomena. We acknowledge, with thanks, NSF and REU Summer Student program support, and the support of the European and US VLBI networks. NAIC is operated by Cornell University under Contract with the National Science Foundation.

Affiliated with

Also associated with

No associations

Rating

Centiarcsecond Structure of Low Frequency Variable Extragalactic Sources does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Centiarcsecond Structure of Low Frequency Variable Extragalactic Sources, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Centiarcsecond Structure of Low Frequency Variable Extragalactic Sources will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1110826