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Register a new userGravitational Lensing Size Scales for Quasars
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G. Chartas
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We review results from our monitoring observations of several lensed quasars performed in the optical, UV, and X-ray bands. Modeling of the multi-wavelength light curves provides constraints on the extent of the optical, UV, and X-ray emission regions. One of the important results of our analysis is that the optical sizes as inferred from the microlensing analysis are significantly larger than those predicted by the theoretical-thin-disk estimate. In a few cases we also constrain the slope of the size-wavelength relation. Our size constraints of the soft and hard X-ray emission regions of quasars indicate that in some objects of our sample the hard X-ray emission region is more compact than the soft and in others the soft emission region is smaller. This difference may be the result of the relative strengths of the disk-reflected (harder and extended) versus corona-direct (softer and compact) components in the quasars of our sample. Finally, we present the analysis of several strong microlensing events where we detect an evolution of the relativistic Fe line profile as the magnification caustic traverses the accretion disk. These caustic crossings are used to provide constraints on the innermost stable circular orbit (ISCO) radius and the accretion disk inclination angle of the black hole in quasar RX J1131-1231.
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Observationally, there are a small fraction GRBs prompt emission observed by Fermi/GBM that are composed of two pulses. Occasionally, the cosmological distance of GRB may be lensed when a high mass astrophysical object reside in path between GRB source and observer. In this paper, we are lucky to find out GRB 200716C with two-pulse emission which duration is a few seconds. We present a Bayesian analysis identifying gravitational lensing in both temporal and spectral properties, and calculate the time decay ($Delta tsim 1.92$ s) and magnification ($gammasim 1.5$) between those two pulses based on the temporal fits. One can roughly estimate the lens mass is about $2.38times 10^{5}~M_{odot}$ in the rest frame. If the first pulse of this GRB near triggered time is indeed gravitationally echoed by a second pulse, GRB 200716C may be a short GRB candidate with extended emission.
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