Slow NIR Flare and Historical NIR light maximum of the FSRQ PKS 1725+123
ATel #17415; L. Carrasco, G. Escobedo, A. Porras, E. Recillas, L. Felix;(INAOE, Mexico)
on 23 Sep 2025; 17:20 UT
Credential Certification: LUIS CARRASCO (carrasco@inaoep.mx)
Subjects: Radio, Infra-Red, Gamma Ray, TeV, AGN, Blazar, Quasar
Following Fermi-LAT detection of gamma-ray activity of FSRQ PKS 1725+123 (ATel#17370) recently reported. On September 15th, 2025 (JD 2460933.6460) we found the Flat Spectrum Radio Quasar PKS 1725+123, also known as 4FGL J1728.0+1216, in an historically bright NIR flare in a lapse over 15 years of observations. And this maximum was slowly reached after a period of time of approximately 100 days. The NIR fluxes in the JHK bands were: J=12.840+/-0.032, H=12.103+/-0.034 and Ks=11.402+/-0.050. These fluxes have almost doubled our previous report of them, (ATel#17127). While the NIR fluxes in the JHK band on JD2460830.9470 it were J=15.003+/-0.030, H=14.181+/-0.044 and Ks=13.224+/-0.030. Hence, the object has undergone an increase in JHK band fluxes of a factor larger than 5 in every band in almost a hundred days. Our observations are carried out with 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). We encourage further multiwavelength observations.
