Multiwavelength flaring activity of PKS 1510-089

Abstract

Aims. In this work, we analyse the multiwavelength brightness variations and flaring activity of FSRQ PKS1510-089, aiming to constrain the position of the emission sources. Methods. We report 7 mm (43 GHz) radio and R-band polarimetric observations of PKS1510-089. The radio observations were performed at the Itapetinga Radio Observatory, while the polarimetric data were obtained at the Pico dos Dias Observatory. The 7 mm observations cover the period between 2011 and 2013, while the optical polarimetric observations were made between 2009 and 2012.Results. At 7 mm, we detected a correlation between four radio and γ-ray flares with a delay of about 54 days between them; the higher frequency counterpart occurred first. Using optical polarimetry, we detected a large variation in polarization angle (PA) within two days associated with the beginning of a γ-ray flare. Complementing our data with other data obtained in the literature, we show that PA presented rotations associated with the occurrence of flares. Conclusions. Our results can be explained by a shock-in-jet model, in which a new component is formed in the compact core producing an optical and/or γ-ray flare, propagates along the jet, and after some time becomes optically thin and is detected as a flare at radio frequencies. The variability in the polarimetric parameters can also be reproduced; we can explain large variation in both PA and polarization degree (PD), in only one of them, or in neither, depending on the differences in PA and PD between the jet and the new component.

Optical Polarimetry and Radio Observations of PKS1510-089 between 2009 and 2013

“…In this communication we discussed the monitoring campaign reported by Beaklini et al [13]. At radio wavelengths, We reported a delay between the radio and the γ-ray emission, with the high energy flux density coming first.…”

“…In Figure 2 we show the aligned γ-ray and 7 mm radio light curves, the latter was shifted by 54 days, which resulted in a good match between the maxima in both light curves. Although the different variability timescales makes it difficult to use a statistical test to confirm this delay, an analysis of the epochs of occurrence of the flares at both wavelengths by Beaklini et al [13] indicated a time delay of 54 days. The existence of delays between flares at high energies and radio wavelengths is already known in AGNs [14].…”

“…The 2009 long term PA rotation event was monitored by different authors [9][10][11]13,18]. We could minimize the gaps between the observation and assume that the angle rotated by the smallest difference, as we shown in a schematic view in Figure 3.…”

“…Using this criterion we detected other 7 events besides our detection which are indicated by dashed line in the figure. Beaklini et al [13] showed that if the optical and/or gamma-ray flares are associate with the formation of a new jet component, depending on its polarimetric properties, it is possible to obtain different amount of variation in PA, including no variation at all. In Figure 4, one can see two of these rapid PA variation exactly coincident with the flares, although they were also detected without a corresponding flare.…”

“…In this report, we discuss some details of our radio and optical polarimetric monitoring program of PKS1510-089, which resulted in several publications [7,12,13]. We compared our polarimetric data with others available in the literature in a attempt to minimize the gaps between the observations and in order to obtain a better understanding of the emission variability.…”