AAS 197, January 2001
Session 40. REU: Instrumentation, Star Clusters and Galaxies
Display, Tuesday, January 9, 2001, 9:30am-7:00pm, Exhibit Hall

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[40.09] Free-Free Absorption on Parsec Scales in NGC 1052

T. Woodruff (Southwestern Univ.), M. Claussen, J. Ulvestad (NRAO)

Two groups of very luminous water maser emission have been detected toward the elliptical galaxy NGC 1052. An apparent gap in the continuum emission found near these water masers at a frequency of 22 GHz in a 1995 VLBI image (Claussen et al. 1998, ApJL, 500, 129) suggested the possibility of strong free-free absorption. Utilizing two epochs of VLBI data taken in conjunction with the VLBI Space Observatory Programme (VSOP) at 1.6 and 5 GHz in 1999, we confirm the presence of free-free absorption in a region near this gap. An analysis of the orientation of the galaxy with respect to the observer is also presented, along with calculations of the electron density of the obscuring medium. Earlier (1997) VLBA observations at 2.3 and 8.6 GHz of NGC 1052 taken under the USNO Radio Reference Frame program were also utilized to calculate jet component velocities and variability so that the 1995 22 GHz image could be better correlated with the 1999 VSOP observations.

The VSOP project is led by the Japanese Institute of Space and Astronautical Science. This research has made use of the United States Naval Observatory Radio Reference Frame Image Database. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

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