GRB 200216A

The Fermi GBM team reports the detection of a likely LONG GRB

At 09:07:25 UT on 16 Feb 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200216A (trigger 603536850.030844 / 200216380).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 318.7, Dec = 6.5 (J2000 degrees, equivalent to J2000 21h 14m, 6d 30'), with a statistical uncertainty of 11.4 degrees.

The angle from the Fermi LAT boresight is 68.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200216380/quicklook/glg_skymap_all_bn200216380.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200216380/quicklook/glg_healpix_all_bn200216380.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200216380/quicklook/glg_lc_medres34_bn200216380.gif

James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), and Jamie Kennea (PSU) report:

Swift/BAT did not trigger on GRB 200216A.

The Fermi/GBM Flight-Position notice, distributed at T0+24 seconds, from 
the Fermi/GBM detected GRB 200216A (GCN. 27096) triggered the Swift 
Mission Operations Center operated Gamma-ray Urgent Archiver for Novel 
Opportunities (GUANO; Tohuvavohu et al. 2020, in prep).

The GUANO is a fully autonomous, extremely low latency, spacecraft 
commanding pipeline designed for targeted recovery of BAT event mode data 
around the times of compelling astrophysical events to enable more 
sensitive GRB searches.

Upon trigger by the Fermi notice, GUANO sent a command to the Swift Burst 
Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from 
[-50,+150] seconds around the time of GRB 200216A.

All the requested event mode data was delivered to the ground.

In a ground analysis of the data, using the normal BAT imaging technique, 
we detect GRB 200216A with a SNR of 7.5.

With a more sophisticated maximum likelihood analysis (DeLaunay et al., 
2020 in prep.) on the event-mode data we detect GRB 200216A more 
confidently, with a square root of the test statistic (sqrt(TS)) of 15.4. 
The sqrt(TS) behaves similarly to SNR.

The BAT ground-calculated position is
RA, Dec = 311.4378, -11.6580 deg which is
   RA(J2000)  = 311d 26' 16.08"
   Dec(J2000) = -11d 39' 28.8"
with an uncertainty of 3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 40%.

This arcminute location is consistent with the localization region 
distributed by the Fermi/GBM team (GCN. 27096).

No XRT or UVOT follow-up will take place due to the source's proximity to 
the sun (1.2 hours). We encourage follow-up from instruments capable of 
observing near the sun.

S. Lesage, B. Mailyan, S. Poolakkil, and C. Meegan (all UAH)
report on behalf of the Fermi GBM Team:

"At 09:07:25.03 UT on 16 February 2020, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 200216A (trigger 603536850 / 200216380)
which was also detected via Swift ground analysis (DeLaunay et al. 2020,
GCN 27107
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 )
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 68
degrees.

The GBM light curve consists of a single bright pulse followed by
some extended emission with a duration (T90) of about 8.0 s (10-1000 keV).
The time-averaged spectrum from T0-5.0 s to T0+2.5 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is 0.9 +/- 0.9 and
the cutoff energy, parameterized as Epeak, is 180.0 +/- 34.0 keV

The event fluence (10-1000 keV) in this time interval is
(4.4 +/- 0.9)E-07 erg/cm^2.
The 1-sec peak photon flux measured starting from T0-4.16 s
in the 10-1000 keV band is 0.92 +/- 0.1 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/"