IIA Institutional Repository

Rapid optical variability of TeV blazars

Show simple item record

dc.contributor.author Gopal-Krishna
dc.contributor.author Goyal, A
dc.contributor.author Joshi, S
dc.contributor.author Karthick, C
dc.contributor.author Sagar, R
dc.contributor.author Wiita, P. J
dc.contributor.author Anupama, G. C
dc.contributor.author Sahu, D. K
dc.date.accessioned 2011-09-07T11:25:04Z
dc.date.available 2011-09-07T11:25:04Z
dc.date.issued 2011-09
dc.identifier.citation Monthly Notices of the Royal Astronomical Society, Vol. 416, No. 1, pp. 101–117 en
dc.identifier.uri http://hdl.handle.net/2248/5551
dc.description Restricted Access en
dc.description.abstract In this first systematic attempt to characterize the intranight optical variability (INOV) of TeV-detected blazars, we have monitored a well-defined set of nine TeV blazars on total 26 nights during 2004–10. In this R- or V-band-monitoring programme only one blazar was monitored per night and the minimum duration was close to 4 h, the average being 5.3 h per night. Using the CCD for strictly simultaneous photometry of the blazar and nearby reference stars (N-star photometry), an INOV detection threshold of ∼1–2 per cent was achieved in the densely sampled differential light curves derived from our data. We have further expanded the sample by including another 13 TeV blazars, taking advantage of the availability in the literature of INOV data, including those published earlier in our programme. The selection criteria for this set of 13 blazars conform to the basic criteria we had adopted for the first set of nine blazars we have monitored presently. This enlarged, well-defined representative sample of 22 TeV blazars, monitored on a total of 116 nights (including 55 nights newly reported here), has enabled us to arrive at the first estimate of the INOV duty cycle (DC) of TeV-detected blazars. Applying the conservative, but commonly employed, C-test, the INOV DC is found to be 59 per cent, which decreases to 47 per cent if only INOV fractional amplitudes (ψ) above 3 per cent are considered. These observations also permit, for the first time, a comparison of the INOV characteristics of the two major subclasses of TeV-detected BL Lac objects, namely low-peaked BL Lac objects (LBLs) and high-peaked BL Lac objects (HBLs), for which we find the INOV DCs to be ∼63 and 38 per cent, respectively. This demonstrates that the previously recognized INOV differential between LBLs and HBLs persists even when only their TeV-detected subsets are considered. Despite dense sampling, the intranight light curves of the 22 TeV blazars have not revealed even a single feature on time-scale substantially shorter than 1 h, even though the inner jets of TeV blazars are believed to have exceptionally large bulk Lorentz factors (and correspondingly stronger time compression). An intriguing feature, clearly detected in the light curve of the HBL J1555+1111, is a 4 per cent ‘dip’ on a 1 h time-scale. This unique feature could have arisen from absorption in a dusty gas cloud, occulting a superluminally moving optical knot in the parsec-scale jet of this relatively luminous BL Lac object. en
dc.language.iso en en
dc.publisher Wiley-Blackwell en
dc.relation.uri http://dx.doi.org/10.1111/j.1365-2966.2011.19014.x en
dc.rights © Wiley-Blackwell en
dc.subject Galaxies: active en
dc.subject BL Lacertae objects: general en
dc.subject Galaxies: jets en
dc.subject Galaxies: photometry en
dc.title Rapid optical variability of TeV blazars en
dc.type Article en


Files in this item

This item appears in the following Collection(s)

Show simple item record

Search DSpace


Browse

My Account