[vsnet-grb-info 23531] LIGO/Virgo S190901ap: Upper limits from AGILE-GRID observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25630
SUBJECT: LIGO/Virgo S190901ap: Upper limits from AGILE-GRID observations
DATE:    19/09/03 14:32:13 GMT
FROM:    Martina Cardillo at INAF-IAPS  <martina.cardillo at inaf.it>

M. Cardillo (INAF/IAPS), F. Verrecchia (SSDC,and INAF/OAR), F. Longo 
(Univ. Trieste,
and INFN Trieste),C. Pittori, F. Lucarelli (SSDC, and INAF/OAR), M. 
Tavani (INAF/IAPS
and Univ. Roma Tor Vergata),C. Casentini, G. Piano, A. Ursi 
(INAF/IAPS),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 S190901ap at T0 = 2019-09-01 
23:31:01.838
UTC a preliminary analysis of the AGILE exposure at T0 shows that the 
Gamma-Ray
Imaging Detector (GRID) exposure covered about 20% of the 90% c.l. 
localization
region (LR) (13% of 90% c.l. localization region (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 S190901ap 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 3.00e-07 to 9.32e-06 erg cm^-2 s^-1, with exposure of about 16% of 
the LR over
the time interval ( T0s ; T0 + 10s );
from 3.59e-08 to 6.91e-06 erg cm^-2 s^-1, with exposure of about 26% 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.