[ Previous | Next | ADS ]

Fermi/LAT search for counterpart to the IceCube event 67093193 (run 127853)

ATel #9008; G. Vianello (Stanford), J. D. Magill (UMD/GSFC), N. Omodei (Stanford), D. Kocevski (NASA/Goddard), M. Ajello (Clemson), S. Buson (NASA/GSFC), F. Krauss (ECAP/FAU), J. Chiang (SLAC/Kipac)
on 28 Apr 2016; 22:34 UT
Credential Certification: Giacomo Vianello (giacomov@slac.stanford.edu)

Subjects: Gamma Ray, >GeV, Neutrinos, AGN, Transient

on behalf of the Fermi-LAT team:

We have searched the Fermi Large Area Telescope data for a high-energy gamma-ray counterpart for the IceCube High Energy Starting Event (HESE) 67093193, detected in run 127853 on 2016-04-27 05:52:32.00 UT (AMON GCN notice rev. 2, http://gcn.gsfc.nasa.gov/notices_amon/67093193_127853.amon . See http://gcn.gsfc.nasa.gov/doc/Public_Doc_AMON_IceCube_GCN_Alerts_v2.pdf for a description of HESE events and related GCN notices).

The localization region was outside the LAT field of view at the time of the detection by IceCube (T0). It entered the LAT FoV at ~T0 + 6140 s and exited again at ~T0 + 8420 s. We ran the standard GRB search (Vianello et al. 2015) plus an ad-hoc search for a counterpart in this time interval and in 10 h intervals before and after the event. We found no significant transient candidate associated with the neutrino event.

The Automated Science Processing search, which looks for variation in flux from known sources and for new transients on different time scales (Chiang 2012), did not detect any transient or flaring source consistent with the IceCube event position during the six-hour intervals before and after the neutrino detection time, nor during the day before and after the event.

The Fermi All-Sky Variability Analysis (FAVA), a photometric analysis currently designed to detect variable sources on one-week timescales, did not find any excess emission consistent with the most current localization. Likewise, an examination of previous weeks analyzed by this technique reveals no long timecale flaring sources compatible with the localization region.

The 90% containment provided by IceCube, which is ~36 arcmin wide, contains no LAT source from the Fermi Point Source catalog (3FGL, Acero et al. 2015). The 5 closest sources are all blazars:

Source nameDistanceAssociationBlazar Type
3FGL J1603.7+1106108'MG1 J160340+1106BL Lac
3FGL J1608.6+1029117'4C +10.45FSRQ
3FGL J1555.7+1111147'PG 1553+113BL Lac
3FGL J1552.1+0852153'TXS 1549+089BL Lac
3FGL J1546.0+0818249'1RXS J154604.6+081912BL Lac

We note in particular that PG 1553+113 has been detected in high state on 2016-04-27 in the 0.3-10 keV band by the Swift X-ray Telescope (B. Kapanadze, ATel #8998), although we do not detect any significant change in flux above 100 MeV.

The Fermi-LAT points of contact for this event are Giacomo Vianello (Burst Advocate, giacomov@stanford.edu) and Jeffrey D Magill (Flare Advocate, jmagill@umd.edu).

The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.