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Detection of an optical outburst from blazar S4 1030+61

ATEL # 2623; P. S. Smith and G. J. Bechetti (Steward Observatory, University of Arizona)
on 17 May 2010; 9:25 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: Paul S. Smith (

Subjects: Optical, Gamma Ray, >GeV, AGN, Quasars
Referred to by ATEL #: 2625, 2628

Optical observations of S4 1030+61 (TXS 1030+611, RA=158.46429 deg, Dec=60.85203 deg, J2000.0) with the SPOL spectropolarimeter and the 2.3m Bok Telescope on Kitt Peak, AZ have found this blazar to be in outburst and highly polarized. These observations were prompted by ATEL #2622. On May 17, 2010 we estimate V=15.7 from spectrophotometry and the object shows a featureless, power-law continuum. For comparison, S4 1030+61 was found to be at g=18.88 and r=18.46 in the third data release of the Sloan Digital Sky Survey (Abazajian et al. 2005, AJ, 129, 1755). In addition, its linear polarization was measured to be P=12.5+/-0.1%, with a polarization position angle of 171.1+/-0.1 deg. The optical activity in S4 1030+61 suggests that it is the optical counterpart to the gamma-ray source 1FGL J1033.8+6048 (Abdo et al. 2010; arXiv:1002.2280), which is currently undergoing increased gamma-ray activity as observed by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope (ATEL #2622). Ciprini et al. (ATEL #2622) indicate that 1FGL J1033.8+6048 may also be associated with another flat-spectrum radio quasar, GB6 J1032+60511 (87GB 102932.2+610651, RA=158.22483 deg, Dec=60.85767 deg, J2000.0), however, visual inspection using the CCD guiding system of the Bok Telescope failed to detect this source down to a limiting magnitude of about 22 on May 17. Further observations are encouraged during this period of gamma-ray activity to confirm the resolution of the counterpart association to 1FGL J1033.8+6048.

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