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Session 59 - Relativistic Astrophysics.
Oral session, Thursday, January 08
The extremely luminous, redshift 2.3 IRAS source F10214+4724 has a narrow arc morphology and is thought to be highly magnified by a foreground gravitational lens. This magnification permits studies of the source at an effective angular resolution far higher than would be possible without the lens.
Imaging polarimetry of the source has been obtained with HST's Faint Object Camera in the F437M filter, which is free of strong emission lines. Preliminary analysis shows that the polarization angle varies significantly across the arc, indicating that different parts of the reflection region are imaged onto different parts of the arc. This places constraints on the source geometry which are unobtainable from intensity information alone. The total polarization of 28% agrees well with ground-based results.
In total flux, the diffraction limited blue image shows the arc to counterimage ratio is significantly greater than in redder passbands (F814W and K), implying greater magnification in the present data. The arc is unresolved in the radial direction at the 0.05 arcsec level, and is shorter than at the red wavelengths.
Upcoming C IV emission-line images using WFPC2 will probe the lensing characteristics of the narrow-line region, providing information complementary to that provided by the pure continuum reflection images taken with FOC.
Program listing for Thursday