TITLE:   GCN CIRCULAR
NUMBER:  26005
SUBJECT: ANTARES 191011A: AMON + ANTARES Identification of a High-Energy Neutrino + Fermi LAT Coincidence
DATE:    19/10/14 13:52:26 GMT
FROM:    Derek B. Fox at Penn State  <dbf11@psu.edu>

C. F. Turley and D. B. Fox (for AMON https://www.amon.psu.edu/),
M. Ageron (CNRS/CPPM), A.Coleiro (Univ. de Paris/APC), D. Dornic
(CNRS/CPPM), & A. Kouchner (Univ. de Paris/APC ) (for ANTARES) report:

"During operations of the AMON ANTARES + Fermi LAT neutrino +
gamma-ray multimessenger alerts, at 2019 October 11 at 15:54:32 UT, we
identified a coincidence between a single ANTARES neutrino and a Fermi
LAT photon (false alarm rate of 1.21 per year). An alert was
automatically generated and, after human review, distributed to AMON
partner facilities at 2019 October 14 at 13:23:22 UT. We are now
reporting this alert publicly. Alert details are as follows:

    Date:  11 October 2019
    Time:  15:54:32 UT
    R.A.:  03:19:51.8 (J2000)
    Dec.:  18:48:27 (J2000)
    r_90:  0.40 deg (90%-containment)
    FAR:   1.212 yr-1

ANTARES 191011A is a high-energy neutrino-induced muon event detected
by ANTARES (Ageron et al. 2011) with coordinates R.A. 51.02,
Dec. +19.12 (J2000) at 15:57:34 UT, and a p-value based on the number
of hits used for the reconstruction of 0.542, which relates to the
deposited energy.

The minimum false alarm rate coincidence from our analysis associates
this neutrino with one Fermi LAT photon. The photon is detected at
15:51:30 UT with coordinates R.A. 49.9403, Dec. 18.7982 and energy 8.6
GeV.  The best-fit localization and uncertainty for a point source
yielding the ANTARES 191011A neutrino and the photon is as quoted
above. The false alarm rate for ANTARES neutrino + Fermi LAT gamma-ray
coincidences of this quality or better is 1 per 0.83 years.

Details of the ANTARES + Fermi LAT coincidence search procedures are
provided in Ayala Solares et al. (AMON + ANTARES) 2019 (ApJ accepted,
ArXiv:1904.06420). False alarm rates are established from 73,000 years
of simulated observation and take into account the point spread
functions of the associated neutrino + photons, the known backgrounds
at this sky position, the energy of the neutrino, and the energies of
the Fermi LAT photons (within broad ranges).

This transient is near the Fermi source 3FGL J0319.8+1847, a blazar
also known as RBS0413.

The AMON alert for this coincidence is provided in GCN Alert format
below."

//////////////////////////////////////////////////////////////////////
TITLE: GCN/AMON NOTICE
NOTICE_DATE: Fri 11 October 2019 15:54:32.38 UT
NOTICE_TYPE: Fermi-LAT ANTARES coincidence
AMON_NUM: 1436255238
SRC_RA: 49.9659d {+03:19:51.8} (J2000),
49.2533d {+03:17:00.8} (1950)
SRC_DEC: +18.8074d {+18:48:27} (J2000),
+18.6271d {+18:37:38} (1950)

SRC_ERROR90: 0.40 [deg, stat, 90% containment]
DISCOVERY_DATE: 18753 TJD;  284 DOY; 19/10/11 (yy/mm/dd)
DISCOVERY_TIME: 57272 SOD {15:54:32.38} UT
REVISION: 0
DELTA_T: 363.24 [sec]
SIGMA_T: 181.62 [sec]
FAR: 1.21 [yr^-1]
SUN_POSTN: 197.5417d {+13h 10m 10s} -7.4458d {-07d 26’ 45"}
SUN_DIST: 146.52 [deg] Sun_angle= 9.768 [hr]
MOON_POSTN: 9.6792d {+00h 38m 43s} -1.2442d {-01d 14’ 39"}
MOON_DIST: 44.36 [deg]
GAL_COORDS: 165.0713, -31.6601 [deg] galactic lon,lat of the event
COMMENTS: ALERT FROM FERMI-LAT ANTARES COINCIDENCE STREAM