Optical follow-up of TXS 0403-132
ATel #15147; Roberto Nesci (INAF/IAPS)
on 29 Dec 2021; 23:51 UT
Credential Certification: Roberto Nesci (roberto.nesci@inaf.it)
Subjects: Optical, AGN, Blazar
Following the announcement of a very high Gamma-ray flare of the blazar TXS 0403-132 (ATel #15146), I observed it with the 30cm telescope of the Foligno Observatory (MPC K56) and the R(Cousins) filter on 2021-12-29T20:53 UT: bad weather prevented observations closer to the Gamma-ray flare (December 25). Aperture photometry was performed with IRAF/apall, using as comparisons the surrounding stars of the GSC2.3 catalog. The source was detected at Fmag=16.78 +/-0.11, formally equal to the value reported in the catalog. For further check we measured the magnitude of the source using the stars of the PanSTARRS DR1 catalog obtaining rmag=16.91+/-0.09, similar to the catalog value (rmag=16.76). We remark that the two catalogs report magnitudes of the source taken at several years distance, which are rather similar: the offset between the GSC2.3 and the PanSTARRS DR1 magnitudes of the stars in the field of TXS 0403-132 is just 0.17 mag, GSC2.3 being brighter. Apparently therefore the Gamma-ray flare of the blazar TXS 0403-132 produced no corresponding enhancement in the optical band.
