TITLE: GCN CIRCULAR NUMBER: 32288 SUBJECT: GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB DATE: 22/06/28 20:22:56 GMT FROM: Oliver J Roberts at USRA/NASA O.J. Roberts (USRA/NASA), B. Hristov (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 21:21:00.09 UT on 27 June 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220627A (trigger 678057665/220627890) which was also detected by the LAT (N. Di Lalla, et al. 2022, GCN 32283) and observed by Swift-BAT-GUANO (G. Raman, et al. 2022, GCN 32287). The Fermi GBM Final Real-time Localization (GCN 32278) is consistent with the LAT position. The angle from the Fermi LAT boresight is 27 degrees. The GBM light curve shows multiple bursts over a duration (T90) of about 138 s (10-1000 keV). The time-averaged spectrum for the this burst from T0-5 s to T0+289 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.83 +/- 0.02 and the cutoff energy, parameterized as Epeak, is 410 +/- 16 keV. The event fluence (10-1000 keV) in this time interval is (7.88 +/- 0.13)E-05 erg/cm^2. A Band function fits the spectrum equally well with Epeak= 390 +/- 20 keV, alpha = -0.81 +/- 0.03 and beta = -2.68 +/- 0.31. The 1-sec peak photon flux measured starting from T0+171.1 s in the 10-1000 keV band is 5.1 +/- 0.2 ph/s/cm^2. Separately, about 1000 s later at 21:36:56.39 UT, GBM triggered on 678058621/220627901, which localized to a similar location of RA: 207.02 deg. Dec: -28.48 deg. (J2000 degrees, equivalent to J2000 13h 48m, +/- 28d 28'), with a statistical uncertainty of 1.2 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] ). We find the T90 of this multiple pulsed burst of similar shape, to be 127 s (10-1000 keV). The time-averaged spectrum for the this burst from T0-47 s to T0+122 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.12 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 227 +/- 15 keV. The event fluence (10-1000 keV) in this time interval is (2.47 +/- 0.08)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+113.2 s in the 10-1000 keV band is 3.5 +/- 0.2 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/"