GCN Circular 32290
Subject
Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
Date
2022-06-29T07:33:35Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester) and J.A. Kennea (PSU) report on behalf of the
Swift-XRT team:
Swift-XRT observed the blazar WISEA J145820.77+412101.9 for 4.9 ks,
starting at 15:07 UT on 2022 June 28. This blazar was posited by the
Fermi team (GCN Circ. 32285, ATEL #15478) to be the potential
counterpart to a new gamma-ray source, Fermi J1458.0+4119, itself a
possible counterpart to the high energy neutrino IceCube 220624A (GCN
Circ. 32260).
The Swift observations show an approximately constant count-rate of
9+/-2- x 10^-3 ct/sec. A spectrum created from the 26 photons detected
can be fitted with a power-law with a photon index of 3.0 (+1.8, -1.1)
absorbed by a column NH = 1.0 (+2.8, -1.0) x 10^21 cm^-2; the large
uncertainties arising due to the low number of counts. This corresponds
to a 0.3-10 keV flux of 1.72 (+1.14, -0.60) x 10^-13 erg cm^-2 s^-1.
The HEASARC X-ray Master catalogue reports several ROSAT fluxes for this
source, ranging from 3--10 x 10^-13 erg cm^2 s^-1. Converting our
spectrum to the ROSAT PSPC energy band (0.1-2.4 keV), we find a flux of
1.5 (+3.3, -0.4) x 10^-13 erg cm^2 s^-1. Thus, presuming that the
catalogued fluxes correspond to quiscence (which is not guaranteed), we
find no evidence for an X-ray outburst from WISEA J145820.77+412101.9.