Chandra Observations of Microlensing of the Accretion Disk of the Radio-Loud Quasar MG 0414+0534.

G. Chartas, M. Eracleous (PSU), E. Agol (Caltech), G. Garmire (PSU), M. W. Bautz , P. L. Schechter , N. D. Morgan (MIT)

[Contributed talk, 15min.]


We present results from Chandra monitoring of the lensed quasar MG 0414+0534. Our analysis of the spectra and light-curves of the lensed images suggest strongly that microlensing events are present in two of the lensed images. The Chandra light-curve of MG 0414+0534 indicates significant fluctuations for the faintest image C and not in the other images. The double-peaked light-curve of image C is suggestive of a double-caustic crossing. Constraints on the geometry of the continuum source based on fits of microlensing models to the light-curve of image C will be discussed. During the last two observations of our monitoring program a strong Fe K$\alpha$ line with an equivalent width of $\sim$ 640 eV was detected in image B and not in the brighter image A, whereas image C is too faint for detection of the line. We propose that the sudden increase in the line strength in only one of the images can be explained with a caustic crossing that selectively enhances a strip of the reprocessing region of the accretion disk. We present microlensing models that predict the observed magnification of the iron-line without any corresponding enhancement of the continuum. The prospects of constraining the geometry of the accretion disk of distant quasars with microlensing of reprocessed Fe K$\alpha$ lines is discussed.

This research was support by NASA grant NAS 8-38252.



Himel Ghosh