Swift observations of blazars and blazar candidates in and around the error regions of the gold neutrinos IC201114A and IC201115A

ATel #14225; P. Giommi (IAS-TUM), P. Padovani (ESO), T. Glauch (TUM)
on 26 Nov 2020; 14:44 UT
Credential Certification: Paolo Giommi (giommipaolo@gmail.com)

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As part of a program to observe known blazars and sources with blazar-like SEDs inside or close to IceCube astrophysical neutrinos shortly after the neutrino arrival, we have triggered short Swift ToO observations for six sources in the vicinity of IC201114A and IC201115A. The following is a summary of the results of our spectral and photometric analysis.

IC201114A
4FGLJ0658.6+0636= 3HSPJ065845.0+063711. This is a HBL blazar with synchrotron peak frequency of 5E17 Hz. Our (photometric) flux estimation gives an unabsorbed flux of (1.7+/-0.2)E-12 erg/cm2/s (0.3-10keV), photon index of 2.29+/- 0.25 (see also Atel. #14178, #14201 and #14202). The flux during our ToO is about a factor of 2 lower than that observed by SRG/eROSITA about one month before the neutrino arrival (Atel #14199), and is twice as large as in archival 2012 XRT observations No significant spectral changes have been detected compared to previous observations.
VOUJ104.13900+5.65641=WISEAJ065633.43+053922.7 is blazar candidate (based on the VOU_Blazar tool, Chang et al. 2020, Astr. and Computing, 30,100350). The observed unabsorbed (0.3-10 keV) flux is (1.2+/-0.2)E-12 erg/cm2/s, somewhat lower than that derived from archival Rosat observations.
VOUJ104.82000+5.88131 = SDSSJ065916.73+055252.4 is a blazar candidate based on the VOU_Blazar tool. This source was not detected. The 3 sigma upper limit of 6.E-13 erg/cm2/s (0.3-10keV) is consistent with the flux observed in 2013.

IC201115A
4FGL J1250.6+0217=5BZB J1250+0216: The Swift-XRT ToO observation detected this source with low signal to noise ratio with a (0.3-10keV) flux of (2.1+/-0.9)E-13 erg/cm2/s. No previous X-ray observations are available. The X-ray flux is consistent with a SED typical of LBL blazars
4FGL J1311.0+0034=3HSPJ131106.5+003510 is a HBL blazar that we detected with a (0.3-10keV) flux of (1.1+/-0.3)E-12 erg/cm2/s, an intermediate state between previous Rosat and Swift observations, and with a spectral index of 2.1+/0.2
4FGL J1253.8+0327=3HSPJ125347.0+032630 is an HBL blazar detected with a (0.3-10keV) flux of (2.6+/- 0.3)E-12 erg/cm2/s and a photon index of 2.5+/-0.2, somewhat fainter and steeper than previous XRT observations