Multiband variability in the blazar 3C 273 with XMM–Newton

Abstract

We have undertaken a nearly simultaneous optical/UV and X-ray variability study of the flat spectrum radio quasar, 3C 273 using data available from the XMM−Newton satellite mission from June 2000 to July 2012. Here we focus on the multi-wavelength flux variability on both intra-day and long time scales of this very well known radio-loud source. We found high flux variability over long time scales in all bands for which observations were made. The optical/UV variability amplitude was more than twice than that in the X-ray bands. There is some frequency dependence of the variability in optical/UV bands in the sense that the variability amplitude increases with increasing frequency; however, the X-ray emissions disagree with this trend as the variability amplitude decreases from soft to hard X-ray bands. On intraday time scales 3C 273 showed small amplitude variability in X-ray bands. A hardness ratio analysis in the X-ray regime indicates that the particle acceleration mechanism dominates the cooling mechanism during most of the ∼12 year span of these observations.

Multicolor Optical Monitoring of the Quasar 3C 273 from 2005 to 2016

“…Chidiac et al (2016) found that the variations at higher frequencies are leading the lower frequencies, which could be expected in the standard shock-in-jet model. Kalita et al (2015) found high flux variability over long time scales in optical, UV and X-ray bands, and that on intraday time scales 3C 273 shows small amplitude variability in X-ray bands. Madsen et al (2015) investigated the spectral variability in the NuSTAR band and found an inverse correlation between flux and photon index.…”

“…The IDV of blazars is the least well understood type of variations but it can shed light on the location, size, structure and dynamics of the emitting regions and radiation mechanism (e.g. Wagner & Witzel 1995;Ciprini et al 2003Ciprini et al , 2007Kalita et al 2015;Dai et al 2015). The discovery of a periodicity in the variability could have profound consequences in the global understanding of the sources, constituting a basic block for models (Sandrinelli et al 2016).…”

“…The flux and spectral variations of 3C 273 have been extensively studied over the entire electromagnetic spectrum (e.g. Xie et al 1999Xie et al , 2004aGhosh et al 2000;Mantovani et al 2000;Collmar et al 2000;Sambruna et al 2001;Greve et al 2002;Kataoka et al 2002;Courvoisier et al 2003;Jester et al 2005;Attridge et al 2005;Savolainen et al 2006;McHardy et al 2007;Soldi et al 2008;Espaillat et al 2008;Pacciani et al 2009;Dai et al 2009;Fan et al 2009Fan et al , 2014Abdo et al 2010;Ikejiri et al 2011;Rani et al 2011;Vol'vach et al 2013;Beaklini & Abraham 2014;Kalita et al 2015;Esposito et al 2015;Madsen et al 2015;Chidiac et al 2016). Soldi et al (2008) studied the multiwavelength variability of 3C 273.…”

Multi-Wavelength Intra-Day Variability and Quasi-Periodic Oscillation in Blazars

“…Percentage amplitude variation in the time series data was introduced by [18] and used in several papers (e.g., [23,27,30,38]; and the references therein). Another method called excess variance and fractional rms variability amplitude were introduced by [51,52] and extensively used for getting the variability in AGN LCs (e.g., [37,42,53,54]; and the references therein).…”

Origin of X-rays in the low state of the FSRQ 3C 273: evidence of inverse Compton emission

“…They proposed the presence of two X-ray emitting components, where they argued that the hard X-ray emission is not related to the acceleration of electrons by the shocks in the jet, but rather is associated with the long term optical variation and emitted through inverse Compton emission (synchrotron self Compton -SSC and/or external Compton -EC). A multi-wavelength variability study of the source using 12 years of XMM-Newton observations (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012), found that the source was highly variable in all bands from optical to X-rays on long time scales but that there was no evidence for intraday variability in the individual light curves in X-rays (Kalita et al 2015). We also noticed that the amount of X-ray variability disagreed with the frequency dependent variability that is generally found in blazars.…”