HST imaging of four gravitationally lensed quasars
| Autor: | Kathleen Labrie, A. L. King, Rachel L. Webster, D. M. Neri-Larios, Suk Yee Yong, Matthew O'Dowd, Robert Barone-Nugent, Nicholas F. Bate, G. Vernardos, David J. E. Floyd |
|---|---|
| Přispěvatelé: | Astronomy |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
SUBSTRUCTURE
Dark matter FOS: Physical sciences quasars: individual: B 1422+231 Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics gravitational lensing: micro Lambda Gravitational microlensing 01 natural sciences LINE REGION quasars: individual: RXJ 0911+0551 accretion quasars: individual: MG 0414+0534 0103 physical sciences DARK-MATTER Chromatic scale Q2237+0305 010303 astronomy & astrophysics B1422+231 Astrophysics::Galaxy Astrophysics Physics QSO 2237+0305 quasars: individual: WFIJ2026-4536 Accretion (meteorology) 010308 nuclear & particles physics Astronomy and Astrophysics Quasar Radius Astrophysics - Astrophysics of Galaxies accretion discs Wavelength SIZE Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) ACCRETION DISK accretion accretion discs Astrophysics::Earth and Planetary Astrophysics SKY SURVEY MG 0414+0534 |
| Zdroj: | Monthly Notices of the Royal Astronomical Society, 479(4), 4796-4814. Oxford University Press |
| ISSN: | 0035-8711 |
| Popis: | We present new HST WFPC3 imaging of four gravitationally lensed quasars: MG 0414+0534; RXJ 0911+0551; B 1422+231; WFI J2026-4536. In three of these systems we detect wavelength-dependent microlensing, which we use to place constraints on the sizes and temperature profiles of the accretion discs in each quasar. Accretion disc radius is assumed to vary with wavelength according to the power-law relationship $r\propto \lambda^p$, equivalent to a radial temperature profile of $T\propto r^{-1/p}$. The goal of this work is to search for deviations from standard thin disc theory, which predicts that radius goes as wavelength to the power $p=4/3$. We find a wide range of power-law indices, from $p=1.4^{+0.5}_{-0.4}$ in B 1422+231 to $p=2.3^{+0.5}_{-0.4}$ in WFI J2026-4536. The measured value of $p$ appears to correlate with the strength of the wavelength-dependent microlensing. We explore this issue with mock simulations using a fixed accretion disc with $p=1.5$, and find that cases where wavelength-dependent microlensing is small tend to under-estimate the value of $p$. This casts doubt on previous ensemble single-epoch measurements which have favoured low values using samples of lensed quasars that display only moderate chromatic effects. Using only our systems with strong chromatic microlensing we prefer $p>4/3$, corresponding to shallower temperature profiles than expected from standard thin disc theory. Comment: 20 pages, 11 figures, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|