[vsnet-grb-info 15822] GRB 141121A: SPI-ACS/INTEGRAL observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17110
SUBJECT: GRB 141121A: SPI-ACS/INTEGRAL observations
DATE:    14/11/28 18:10:04 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

A. Pozanenko (IKI), P. Minaev (IKI),  V. Vybornov (IKI), A. Volnova 
(IKI), E. Mazaeva (IKI)  report:

We inspected the SPI-ACS data  of INTEGRAL observatory covering trigger 
time of the Swift GRB 141121A (Lien et al., GCN 17075) and MAXI/GSC 
(Honda et al., GCN 17077). At the BAT/Swift trigger time of the GRB 
141121A (UT) T0=03:50:43 we do not found any significant emission above 
background in SPI-ACS data in different time scales (0.05 s, 5 s, and 50 
s).  We also do not find any activity at the second BAT episode (T0+550 
s to T0+675 s).

At the time of about T0-800 s we found in SPI-ACS data the activity 
corresponding to the first Konus-Wind episode (Golenetskii et al., GCN 
17108). The duration of the activity is about 200 s and clearly visible 
in SPI-ACS light curve. The start time of the maximal count rate of 
SPI-ACS light curve (binning with 50 s bin duration) is T0-725 s. In 
both cases TO and T0-725 s the boresight of SPI-ACS is the same and 
equal to 119 degrees. If this episode is related to the GRB 141121A and 
taking into account SPI-ACS energy threshold (>~ 80 keV) one can suggest 
the this episode of GRB 141121A is harder than main activity detected by 
BAT/Swift.

We do not detect any significant activity at the time of the MAXI/GSC 
detection (Honda et al., GCN 17077).

The SPI-ACS light curves can be found at

http://grb.rssi.ru/GRB141121A/grb141121_spi-acs_50sec.png
http://grb.rssi.ru/GRB141121A/grb141121_spi-acs_5sec.png