AAS 197, January 2001
Session 39. Polarimetry and Variability in AGN
Display, Tuesday, January 9, 2001, 9:30am-7:00pm, Exhibit Hall

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[39.06] Parsec-Scale Cores in Seyfert Galaxies

T.A. Ostrowski-Fukuda (University of Denver), J.S. Ulvestad (NRAO)

A study was conducted on 21 Seyfert galaxies, part of a complete sample of 75 galaxies selected by 60-micrometer emission (de Grijp et al. 1992). Observations were made with the Very Long Baseline Array (VLBA) at 1.6 GHz in November and December 1999. Due to trouble with low-frequency phase referencing during the day near solar maximum, only 9 out of 21 galaxies were imaged. Out of 6 resolved galaxies, MCG 8-11-11 was the only one found to have curvature or warping on parsec-scales compared to VLA-scales (40 - 100 pc). There were not enough statistics to compare the different Seyfert types. The ratio of VLBA flux density to that in the VLA core was measured for the 9 galaxies that were imaged, and ranged from 2 to 40 percent. Much of the loss in flux density might be attributed to the problematic phase referencing, although long solution intervals were used in self-cal. It also seems highly likely that there is considerable flux on scales between 20 and 100 mas. Comparison to IRAS fluxes is planned to see if the "missing" flux obeys the radio-far infrared correlation and might be associated with nuclear starbursts. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

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

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