AAS 201st Meeting, January, 2003
Session 11. Seyfert Galaxies and AGNs
Poster, Monday, January 6, 2003, 9:20am-6:30pm, Exhibit Hall AB

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[11.04] Color Variations of Two Blazars: BL Lac and PKS 0736+017

S. D. Clements (Florida Tech, SARA)

Multi-night campaigns to monitor sources for microvariability were undertaken in the summer of 1997 for BL Lac and in early 2002 for PKS 0736+017. BL Lac was observed at Rosemary Hill Observatory in Bronson, Florida and PKS 0736+017 was observed with the SARA telescope on Kitt Peak in Arizona. Both sources underwent dramatic flares and exhibited substantial microvariability. During each campaign, the source was observed alternately through V and R filters so that color variations could be monitored as well. The most commonly reported behavior for such objects is that they become redder when fainter. This is observed in the BL Lac data. These data do not indicate that the point source varies in color however. Instead, they support the notion that the underlying host galaxy contributes a larger fraction of the total flux when the source is faint than when it is bright. More unusual was the observation that PKS 0736+017 was observed to be redder when brighter. The data support the notion that the observed color variation may be related more to the nature of the variation (flaring, subsiding, or quiescent) than to the flux level.

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

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