[vsnet-grb-info 17768] IPN Triangulation of GRB 160310A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19209
SUBJECT: IPN Triangulation of GRB 160310A
DATE:    16/03/19 21:42:04 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin at mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa,
and A. Goldstein, on behalf of the Fermi GBM team, and

S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT team, report:

The long-duration GRB 160310A was detected by Konus-Wind (Frederiks et 
al., GCN Circ. 19167), Fermi (LAT: Vianello et al., GCN Circ. 19158  and 
GBM: Toelge & Hui GCN Circ. 19167), and Swift (BAT), at about 1378 s UT 
(00:22:58). The burst was outside the coded field of view of the BAT.

We have triangulated it to a Konus-GBM annulus centered at 
RA(2000)=178.455 deg (11h 53m 49s)  Dec(2000)=-2.131 deg (-2d 07' 52"), 
whose radius is 76.571 +/- 0.876 deg (3 sigma) and to a Konus-BAT 
annulus centered at RA(2000)=178.592 deg (11h 54m 22s)  Dec(2000)=-2.265 
deg (-2d 15' 53"), whose radius is 76.187 +/- 1.716 deg (3 sigma).

While the GBM position is in a good agreement with both the Konus-GBM 
and the Konus-BAT annuli, the LAT position reported in GCN 19158 is 2.9 
deg (~10 sigma) from the Konus-GBM annulus center line. So we encourage 
further investigation of the LAT position.

Using the method suggested by Pal'shin, et al., ApJS 207, 38, 2013 (sec. 
4.2.1) and assuming a LAT error radius of 6 deg, we obtain the following 
joint LAT/IPN error box:
--------------------------------
  RA(2000), deg    Dec(2000), deg
--------------------------------
Center:
    101.726         -7.1445
Corners:
    100.850         -13.082
    102.648         -13.076
    102.726         -1.228
    100.975         -1.191
---------------------------------
The error box area is 21 sq. deg, and its maximum
dimension is 12 deg (the minimum one is 1.8 deg).

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB160310_T01391/IPN/