2016ApJ...831...43V -
Astrophys. J., 831, 43-43 (2016/November-1)
Observations of the lensed quasar Q2237+0305 with CanariCam at GTC.
VIVES-ARIAS H., MUNOZ J.A., KOCHANEK C.S., MEDIAVILLA E. and JIMENEZ-VICENTE J.
Abstract (from CDS):
We present new mid-IR observations of the quadruply lensed quasar Q2237+0305 taken with CanariCam on the Gran Telescopio Canarias. Mid-IR emission by hot dust, unlike the optical and near-IR emission from the accretion disk, is unaffected by the interstellar medium (extinction/scattering) or stellar microlensing. We compare these "true" ratios to the (stellar) microlensed flux ratios observed in the optical/near-IR to constrain the structure of the quasar accretion disk. We find a half-light radius of R1/2=3.4–2.1+5.3sqrt(\langleM)>/0.3M☉ lt-day at λrest=1736 \mathringA and an exponent for the temperature profile R∝λp of p=0.79±0.55, where p=4/3 for a standard thin-disk model. If we assume that the differences in the mid-IR flux ratios measured over the years are due to microlensing variability, we find a lower limit for the size of the mid-IR-emitting region of R1/2>rsim200 sqrt(\langleM)>/0.3M☉ lt-day. We also test for the presence of substructure/satellites by comparing the observed mid-IR flux ratios with those predicted from smooth lens models. We can explain the differences if the surface density fraction in satellites near the lensed images is α=0.033–0.019+0.046 for a singular isothermal ellipsoid plus external shear mass model or α=0.013–0.008+0.019 for a mass model combining ellipsoidal NFW and de Vaucouleurs profiles in an external shear.
Abstract Copyright:
© 2016. The American Astronomical Society. All rights reserved.
Journal keyword(s):
accretion, accretion disks - dark matter - gravitational lensing: micro - quasars: individual: Q2237+0305 - quasars: individual: Q2237+0305
Simbad objects:
4
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