LAST optical observations of the blazar PKS 0446+11 located inside the IceCube-240105A error region

ATel #16407; S. Garrappa (WIS), E. O. Ofek (WIS), S. Ben-Ami (WIS), R. Konno (WIS), D. Polishook (WIS), Y. M. Shani (WIS), E. Segre (WIS), N. L. Strotjohann (WIS)
on 15 Jan 2024; 18:08 UT
Credential Certification: Simone Garrappa (simone.garrappa@gmail.com)

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We report the observations of the flat-spectrum radio quasar PKS 0446+11 at redshift z = 2.15 (Shaw et al. 2012, ApJ, 748, 49) with the Large Array Survey Telescope (LAST, Ofek et al. 2023; Ben-Ami et al. 2023). The source was recently reported to be coincident with the high-energy neutrino event IC240105A (GCN 35498) and showed flaring activity in gamma-rays (ATel#16398), X-rays (ATel#16397) and Radio (ATel#16399).

We observed the source with no filter (clear) in multiple visits during the night of 8 January 2024. The reported magnitudes are in the LAST native AB system, calibrated relative to the GAIA-DR3 Bp band (i.e., color term was fitted and the source color was assumed to be Bp-Rp=1 mag).

From a preliminary analysis of the night of January 8, we measure the following average fluxes in each visit:

MJD = 60317.754 M = 18.48 +/- 0.06

MJD = 60317.775 M = 18.61 +/- 0.07

MJD = 60317.802 M = 18.51 +/- 0.06

MJD = 60317.829 M = 18.51 +/- 0.06

MJD = 60317.851 M = 18.48 +/- 0.07

MJD = 60317.871 M = 18.43 +/- 0.07

Average color term for the observations is -0.58. All errors include statistical and calibration errors (of about 0.015 mag). The source shows small amplitude variations throughout the observations, consistent with the behavior observed on 10 January 2024 in ATel#16402.