Статья

PG 1115+080: variations of the A2/A1 flux ratio and new values of the time delays

V. S. TsvetkovaInstitute of Radio Astronomy of Nat.Ac.Sci. of Ukraine, Krasnoznamennaya 4, 61002 Kharkov, UkraineV. G. VakulikInstitute of Radio Astronomy of Nat.Ac.Sci. of Ukraine, Krasnoznamennaya 4, 61002 Kharkov, UkraineV. M. ShulgaInstitute of Radio Astronomy of Nat.Ac.Sci. of Ukraine, Krasnoznamennaya 4, 61002 Kharkov, UkraineRudolph E. SchildCenter for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USAВ. Н. ДудиновInstitute of Astronomy of Kharkov National University, Sumskaya 35, 61022 Kharkov, UkraineА. А. МинаковInstitute of Radio Astronomy of Nat.Ac.Sci. of Ukraine, Krasnoznamennaya 4, 61002 Kharkov, UkraineС. Н. НуритдиновAstronomical Institute of Ac.Sci.of Uzbekistan, Astronomicheskaya 33, 100052 Tashkent, UzbekistanБ. П. АртамоновA. Ye. KochetovInstitute of Astronomy of Kharkov National University, Sumskaya 35, 61022 Kharkov, UkraineGeorgi SmirnovA. V. SergeyevInstitute of Radio Astronomy of Nat.Ac.Sci. of Ukraine, Krasnoznamennaya 4, 61002 Kharkov, UkraineV. V. KonichekI. Ye. SinelnikovAlexander ZheleznyakВ. В. БруевичR. GaisinAstronomical Institute of Ac.Sci.of Uzbekistan, Astronomicheskaya 33, 100052 Tashkent, UzbekistanTalat AkhunovAstronomical Institute of Ac.Sci.of Uzbekistan, Astronomicheskaya 33, 100052 Tashkent, UzbekistanО. БурхоновAstronomical Institute of Ac.Sci.of Uzbekistan, Astronomicheskaya 33, 100052 Tashkent, Uzbekistan

Monthly Notices of the Royal Astronomical Societyjournal2010en

ABI

Аннотация

We report the results of our multicolour observations of PG 1115+080 with the 1.5-m telescope of the Maidanak Observatory (Uzbekistan, Central Asia) in 2001–2006. Monitoring data in filter <it>R</it> spanning the 2004, 2005 and 2006 seasons (76 data points) demonstrate distinct brightness variations of the source quasar with the total amplitude of almost 0.4 mag. Our <it>R</it> light curves have shown image C leading B by 16.4 d and image (A1+A2) by 12 d that is inconsistent with the previous estimates obtained by <cross-ref type="bib" refid="b52">Schechter et al. in 1997</cross-ref>– 24.7 d between B and C and 9.4 d between (A1+A2) and C. The new values of time delays in PG 1115+080 must result in larger values for the Hubble constant, thus reducing difference between its estimates taken from the gravitational lenses and with other methods. Furthermore, we analysed variability of the A2/A1 flux ratio, as well as colour changes in the archetypal ‘fold’ lens PG 1115+080. We found the A1/A2 flux ratio to grow during 2001–2006 and to be larger at longer wavelengths. In particular, the A2/A1 flux ratio reached 0.85 in filter <it>I</it> in 2006. We also present evidence that both the A1 and A2 images might have undergone microlensing during 2001–2006, with the descending phase for A1 and initial phase for A2. We find that the A2/A1 flux ratio anomaly in PG 1115+080 can be well explained both by microlensing and by finite distance of the source quasar from the caustic fold.

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Темы

Galaxies: Formation, Evolution, Phenomena Astrophysical Phenomena and Observations Gamma-ray bursts and supernovae

Идентификаторы

DOI: 10.1111/j.1365-2966.2010.16882.x

Цитирования и источники

Цитирований: 2 Использованных источников: 73

Показатели — AkademScholar