GCN Circular 24794

C. Malacaria (NASA-MSFC/USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 22:47:49.34 UT on the 11th of June 2019, 
the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 190611B (trigger 581986074 / 190611950).

The on-ground calculated location, using the GBM trigger
data, is RA =  88.9, DEC =  53.1 (J2000 degrees,
equivalent to 05 h 56 m, 53 d 07 '), with a statistical uncertainty
of 1.0 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, 
with 90% of GRBs having a 3.7 deg error and a small tail suffering a 
larger than 10 deg systematic error 
[Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight 
at the GBM trigger time is 117.0 degrees.

The GBM light curve consists of two broad pulses
with a duration (T90) of about 100.6 s (50-300 keV).
The time-averaged spectrum from T0-0.0 s to T0+18.2 s is
best fit by a Band function with Epeak = 210.3 +/- 18.9  keV,
alpha = -1.00 +/- 0.04, and beta = -1.98 +/- 0.05

The event fluence (10-1000 keV) in this time interval is
(2.43 +/- 0.40)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+71.8 s in the 10-1000 keV band
is 32.4 +/- 0.6 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, 
please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"

[GCN OPS NOTE(16jun19), Per author's request, the "190611A"
in the first sentence was corrected to "190611B".]