Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 14190

GRB 130206A: Fermi LAT Observations
2013-02-07T23:11:00Z (11 years ago)
Judith Racusin at GSFC <>
J. L. Racusin (NASA/GSFC), G. Vianello (Stanford), N. Omodei (Stanford), and D. Kocevski (NASA/GSFC), report on behalf of the Fermi-LAT team:

The Fermi Large Area Telescope (LAT) observed GRB 130206A, detected by Fermi-GBM (Goldstein et al., GCN 14189) and Swift-BAT (De Pasquale et al., GCN 14181).

The burst location was within the LAT field of view at an angle of ~19.4 degrees to the LAT boresight, and had a zenith angle of 69 degrees. No significant excess is seen using standard analysis procedures.  The burst exited the nominal LAT field of view roughly ~600 s after the GBM trigger.  

We estimate the 95% confidence upper limits in the energy range of 100 MeV - 10 GeV, assuming spectral index of -2.1, over the time interval 0-40 s:
F(100MeV-10GeV)  < 3.7e-05 (ph/cm^2/s)
                                    <1.5e-02  (MeV/cm^2/s)
                                    <2.4e-08 (erg/cm^2/s)

Using the non-standard LAT Low Energy (LLE) data selection, >60 counts above background were observed in a single FRED like pulse, peaking ~15 s after the GBM trigger.  This corresponds to a significance of 2.9 sigma without taking into account trial factors, and therefore does not constitute a clear detection. On the other hand, the putative signal shows good correlation with the low-energy (GBM) light curve. Such faint signal is constituted by low energy gamma-rays, below 75 MeV, and therefore has insufficient spatial resolution to provide a reliable LAT localization. Indeed, no events were observed above 75 MeV using the standard analysis classes.

The Fermi LAT point of contact for this burst is Judith Racusin (

The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
Looking for U.S. government information and services? Visit