Microlensing in the double quasar SBS 1520+530

Abstract

Abstract. We present the results of a monitoring campaign of the double quasar SBS 1520+530 at Maidanak observatory from April 2003 to August 2004. We obtained light curves in V and R filters that show small-amplitude ∆m ≈ 0.1 mag intrinsic variations of the quasar on time scales of about 100 days. The data set is consistent with the previously determined time delay of ∆t = (130 ± 3) days by Burud et al. (2002, A&A, 391, 481). We find that the time delay corrected magnitude difference between the quasar images is now larger by (0.14±0.03) mag than during the observations by Burud et al. (2002). This confirms the presence of gravitational microlensing variations in this system.

Adaptive PSF fitting – a highly performing photometric method and light curves of the GLS H1413+117: time delays and micro-lensing effects

“…The micro-lensing rate measured for the A, B, C components, on average, corresponds to the characteristic rate of micro-lensing 10 −4 mag d −1 reported for other known gravitationally lensed quasars (Gaynullina et al 2005;Vakulik et al 2006;Goicoechea & Shalyapin 2010;Tsvetkova et al 2010;Ricci et al 2011). …”

“…The long-term light curves indicate the presence of micro-lensing effects, sometimes displaying a large amplitude with respect to by micro-lensing with induced variability at the level of 10 −4 mag d −1 (Gaynullina et al 2005;Vakulik et al 2006;Goicoechea & Shalyapin 2010;Tsvetkova et al 2010). But here we found out one of the fastest micro-lensing effects with a rate of 10 −3 mag d The flux slope of the B component in 2003 is smaller than those of the other components.…”

“…A wide variety of algorithms have been developed for the determination of time delays in gravitational lens systems. The methods presented here are based on the chi-squared χ 2 (Gaynullina et al 2005;Ullán et al 2006) and dispersion D 2 (Pelt et al 1996) minimizations. In general, all the techniques proceed in a similar way -they try to find how to match at best two given light curves.…”

“…We want to compare the results provided by the two approaches when applied to a moderately sampled data set like ours. The chi-squared χ 2 method that we used is well described in Gaynullina et al (2005). But in our case, we considered three values of the maximum gap (δ = 20, 25 and 30 d), within which linear interpolation was allowed.…”

A 5.5-year robotic optical monitoring of Q0957+561: substructure in a non-local cD galaxy

“…2. Although slow microlensing was detected in light curves of several lensed quasars (e.g., Gaynullina et al 2005;Fohlmeister et al 2007;Shalyapin et al 2009;Eulaers & Magain 2011), typical gradients are too small to play a role in brightness records over relatively short time segments. For example, Hainline et al (2012) used LQLM I data and more recent measurements from the United States Naval Observatory (USNO) to study the r-band flux ratio of Q0957+561.…”