AAS 204th Meeting, June 2004
Session 60 Quasars
Poster, Wednesday, June 2, 2004, 10:00am-7:00pm, Ballroom

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[60.15] The Variable X-ray Absorber of the BAL Quasar UM 425

G. Chartas, W. N. Brandt (Penn State), S. C. Gallagher (UCLA)

We present results from an XMM-Newton observation of the broad absorption line (BAL) quasar UM 425. This is one of the few detected BAL quasars to date that is bright enough in the X-ray band, possibly due to the large lensing magnification, to allow complex spectral analysis. By modeling the spectrum of UM 425 we have obtained constraints on the column density and ionization state of the outflowing absorbing gas. A comparison between these constraints and those obtained from a previous Chandra observation of this object indicate significant variability in the properties of the absorber over a period of about 1.5years. We present several interpretations for this detected variability. We acknowledge financial support from NASA grant NAG5-13543.


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