A possible outburst of B3 1029+415 serendipitously detected by Swift

ATel #1180; Luigi Foschini (INAF/IASF-Bologna), Fabrizio Tavecchio (INAF/OA Brera, Milano), Gabriele Ghisellini (INAF/OA Brera, Milano), Rita M. Sambruna (NASA/GSFC)
on 14 Aug 2007; 05:55 UT
Credential Certification: Luigi Foschini (foschini@bo.iasf.cnr.it)

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We report about the serendipitous discovery of a possible outburst from a radio-loud AGN with the Swift satellite.

The radio source B3 1029+415, classified as galaxy by the Sloan Digital Sky Survey (SDSS), although with no redshift (see http://cas.sdss.org/astrodr6/en/tools/explore/obj.asp?ra=158.136667&dec=41.280444 ), was serendipitously detected in the field of view of Swift/XRT during the observation of the nearby blazar 1Jy 1030+415 (6' away) performed on June 30, 2006 (obsID 00035397002, exposure 8.9 ks). Although the low statistics prevents a detailed spectral analysis, it is possible to measure the photon index as 1.6 +/- 0.6 absorbed by the Galactic column (1E+20 cm^-2). The 2-10 keV flux is 2.4E-13 erg/cm2/s. B3 1029+415 appeared to be in an active state, since it was not detected in a previous observation performed on Feb 21, 2006 (obsID 00035397001, exp. 3.1 ks), with an upper limit (3 sigma) < 1E-13 erg/cm2/s in the 2-10 keV energy band.

An inspection of UVOT data gives the following observed magnitudes for the June 30, 2006 observation: UVW1 = 18.1 +/- 0.1, UVM2 = 18.3 +/- 0.2, UVW2 = 19.1 +/- 0.1. The optical filters exposures were severely affected by a nearby strong source, which did not allow to extract meaningful magnitudes. In the Feb 21, 2006 observation, the source was not detected with upper limits (3 sigma) of UVW1 < 19.3, UVM2 < 19.3, UVW2 < 19.6, confirming the suggestion that the source was active during the June 30 observation.

This is also the first X-ray detection of B3 1029+415, to our knowledge.

We acknowledge the use of public data from the Swift data archive.