Observations of radio sources J0258+2030 and J0245+2405, possible counterparts to IceCube-211125A, with the Zwicky Transient Facility
ATel #15080; Simeon Reusch (DESY), Robert Stein (Caltech)
on 30 Nov 2021; 21:33 UT
Credential Certification: Robert Stein (rdstein@caltech.edu)
Subjects: Radio, Optical, Neutrinos, AGN, Blazar
We report optical observations of two compact radio sources identified as possible counterparts (ATel #15076) to high-energy neutrino IceCube-211125A (GCN #31126).
The Zwicky Transient Facility (ZTF) has observed the region repeatedly as part of routine survey operations, most recently on 2021-11-24.27 UT. All images were processed through the ZTF reduction and image subtraction pipelines at IPAC (Masci et al. 2019).
J0245+2405 has a catalogued redshift of z=2.2. No flaring activity has been seen in recent weeks, with the most recent detection at r=19.86+/-0.10 for J0245+2405 on 2021-09-02.47 UT. The full lightcurve for J0245+2405 is given here .
J0258+2030 is a BL Lac, and was coincident with both IC191231A and IC211125A. Near the time of the first neutrino detection on 2019-12-31.46 UT, there are no indications of short-term flaring activity. The flux in the r-band does appear to be above the historical average in our data, but not significantly so. No flaring activity was seen in recent weeks coincident with the detection of the second neutrino, with the source instead appearing to be in a low optical state. The most recent detection was r=20.60+/-0.17, also on 2021-09-02.47 UT. The full lightcurve for J0258+2030 is given here .
ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; DESY, Germany; TANGO, Taiwan; UW Milwaukee, USA; LANL, USA; TCD, Ireland; IN2P3, France.
