Optical follow-up of GB6 J0742+5444

ATel #17632; Roberto Nesci (INAF/IAPS)
on 27 Jan 2026; 08:30 UT
Credential Certification: Roberto Nesci (roberto.nesci@inaf.it)

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Following the notice of a strong Gamma ray activity of the FSRQ GB6 J0742+5444 (Atel #17628) I observed the source on 2026-01-26 around UT 18:30 with the 30 cm telescope of the Foligno Observatory (MPC K56) equipped with a CMOS ZWO294M camera and Bessell B, V, Rc, Ic filters. Comparison stars were taken from the APASS9 catalog and aperture photometry was made with IRAF/apphot. The following magnitudes were derived B=16.26+-0.05; V=15.65+-0.05; Rc=15.28+-0.05; Ic=14.66+-0.07. The FERMI-LAT light curve of GB6 J0742+5444 shows enhanced Gamma ray luminosity around MJD 60032 and 55671. The ATLAS optical light curve, available since MJD=57778, shows that the quiescent optical luminosity is around "o"=18.5, while it was peaked at "o"=14.95 during the Gamma ray outburst of MJD 60032, and is at 14.7 during the present, longer, outburst. Our measure is in good agreement with the ATLAS one. The very good correlation between Gamma ray and optical luminosities is common in most LFP Blazars. A linear fit in the plane Log(nu) - Log(Flux) of our B,V,Rc,Ic magnitudes gives a slope -1.6+-0.1, a typical value for Blazars (see e.g. Nesci et al. 2003, MemSAIt 74, 169). Further multiwavelength observations are encouraged to check if the spectral slope changes when the source returns to its quiescent level.