Further brightening and spectral energy changes of the Blazar BZBJ0958+6533
ATel #17672; L. Carrasco, A. Porras, L. Felix, G. Escobedo, E. Recillas;(INAOE, Mexico)
on 12 Feb 2026; 00:30 UT
Distributed as an Instant Email Notice Transients
Credential Certification: LUIS CARRASCO (carrasco@inaoep.mx)
Subjects: Radio, Infra-Red, Optical, Gamma Ray, AGN, Blazar, Quasar
Here, we report a further light increase of the NIR flare of the intermediate redshift blazar BZBJ0958+6533 (z=0.368), cross identified with the radio source FSQR S40954+658 and the gamma ray source 4FGLJ0958.7+6534. On February 9th, 2026 (JD2461080.8972), our determination of the NIR fluxes in the JHKs bands were: J=12.48+/-0.04, H=11.58+/-0.02 and Ks=10.94+/-0.02 respectively. Hence, we found the object continuing its recent NIR outburst previously reported (see ATel#17623). The NIR fluxes in the JHK bands on JD 2461060.9072 were then, J=13.212+/-0.05, H=12.365+/-0.02 and Ks=11.489+/-0.05. Thus, in this lapse of 20 days, the object has doubled its luminosity in the JH bands while in Ks has undergone an increase by a factor 1.7. The present day increments in flux with respect to our previous determination on JD2460844.6486 are about a factor of 9 in the J and H bands, while in Ks the flux increase has been only a factor of 4. This fact implies that an important change of the NIR spectral energy distribution (SED) is taking place in this object. This kind of SED changes
are not common, given that a simple increase of a synchrotron component would not change the color of the source, contrary to what its been observed. Our observations are carried out using CANICA instrument at the 2.1m telescope of the Guillermo Haro Observatory, which is operated by the National Institute for Astrophysics, Optics and Electronics (INAOE, Mexico).
