TITLE: GCN CIRCULAR NUMBER: 32691 SUBJECT: GRB221009A: INTEGRAL detection of Hard X-ray emission up to 38 hours after trigger DATE: 22/10/11 16:05:23 GMT FROM: Volodymyr Savchenko at ISDC,U of Geneve Volodymyr Savchenko (UNIGE, EPFL), Carlo Ferrigno, Enrico Bozzo (UNIGE), D. Gotz (CEA Paris Saclay), S. Mereghetti (INAF/IASF Milano),  Antonio Martin Carrillo, Lorraine Hanlon (UCD), Elisabeth Jourdain, Jean-Pierre Roques (IRAP), Thomas Siegert (University of Würzburg), Erik Kuulkers, Celia Sanchez (ESA) Following the detection of the record-breaking GRB221009A by Swift/BAT (GCN #32632,#32635), Fermi/GBM (GCN #32636), INTEGRAL/SPI-ACS (GCN #32660), we have performed INTEGRAL pointed observations of the GRB221009A location. INTEGRAL pointed observation lasted from 2022-10-10T14:31:40 (T0 + 25.2 hours, where T0 is 2022-10-09T13:17:00) to 2022-10-11T03:18:20 (T0 + 38.0 hours) with a total exposure time of 30.2 ks (for ISGRI). In the complete observation, the source is clearly detected in JEM-X1, JEM-X2 (3-30 keV), and ISGRI (28 - 80 keV), with S/N of 27.8, 27.3, 15.0 respectively. The joint JEM-X and ISGRI spectra can be satisfactorily modeled between 3 and 80 keV with a single powerlaw of slope 2.15 +/- -0.07 (90% confidence) with a flux of 4.4e-10 +/- -2.1e-11 erg/cm2/s (3 - 80 keV). This might indicate a single spectral component spanning from from hard X-ray to Fermi/LAT (GCN #32658). Combination of bright Hard X-ray afterglow with gamma-ray emission was also found in GRB120711A (Martin-Carrillo et al. 2014 A&A 567, 84) and GRB130427A (Kouveliotou et al. 2013 ApJ 779L, 1K) - in fact GRB221009A appears rather similar to GRB120711A, but at 10 times smaller distance. Within the relatively short JEM-X not ISGRI lightcurves, we do not observe any evidence for flux decrease. Further INTEGRAL observations are scheduled between 2022-10-11 13:52:21 and 2022-10-13 00:58:26. These observations will overlap with the planned observation of IXPE (GCN #32690). We are grateful to the INTEGRAL Ground Segment team for quickly scheduling the observations. Images and reduced data related to this publication can be found here: https://zenodo.org/record/7186289