[vsnet-grb-info 24956] LIGO/Virgo S200213t: upper limits from AGILE/GRID observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27055
SUBJECT: LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
DATE:    20/02/13 09:27:53 GMT
FROM:    Francesco Longo at U of Trieste,INFN Trieste  <franzlongo1969 at gmail.com>

F. Longo (Univ. Trieste, and INFN Trieste), G. Piano, C. Casentini
(INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata),
M. Cardillo, A. Ursi (INAF/IAPS), F. Lucarelli, C. Pittori, F. Verrecchia
(SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani
(INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), report on behalf of
the AGILE Team:

In response to the LIGO-Virgo GW event S200213t at T0 = 2020-02-13
04:10:40.328 (UTC) a preliminary analysis of the AGILE exposure at T0
shows that the Gamma-Ray Imaging Detector (GRID) exposure covered
the 32% of the 90% c.l. localization region (LR) (4% of 90% c.l. LR is
occulted by Earth).

We performed an analysis of the GRID data in the energy range
50 MeV - 10 GeV on T0, where good exposure of the S200213t 90%
c.l. LR was available.

No candidate gamma-ray transient was detected.

The following preliminary GRID values of 3-sigma upper limit (UL) are
obtained:

from 8.7e-07 to 7.2e-06 erg cm^-2 s^-1, with exposure of about 32% of
the LR over the time interval ( T0 -2s ; T0 + 2s );
from 3.3e-07 to 6.4e-06 erg cm^-2 s^-1, with exposure of about 38% of
the LR over the time interval ( T0s ; T0 + 10s );
from 3e-08 to 1.5e-06 erg cm^-2 s^-1, with exposure of about 48% of
the LR over the time interval ( T0s ; T0 + 100s );

These measurements were obtained with AGILE observing a large portion of
the sky in spinning mode. Additional analysis of AGILE data is in progress.