Two years ago, we initiated a multi-year program (AO-16 and AO-17) aimed at creation of an ultra-deep extragalactic field in the direction centered on galaxy M81. We now request new INTEGRAL observations in order to continue our program. This ultra-deep field will become INTEGRALs legacy for studies of the AGN population at hard X-ray fluxes as low as fewx10^-12 erg s^-1 cm^-2, and shall provide a ground for unique synergy of INTEGRAL with the all-sky X-ray surveys by the eROSITA and ART-XC telescopes on board the SRG observatory, which began in December 2019. We ask for additional 5 Ms of INTEGRAL observations, 2.5 Ms in AO18 (2021) and 2.5 Ms in AO19 (2022), to reach a sensitivity of 2x10^-12 erg cm^-2 s^-1 in the 17-60 keV energy band by the midtime of the SRG 4-year all-sky survey.
The INTEGRAL (International Gamma-Ray Astrophysics Laboratory) mission, launched by the European Space Agency (ESA) on October 17, 2002, was designed to study high-energy phenomena in the universe. INTEGRAL was operating until february 2025 and it was equipped with three high-energy instruments: the Imager on Board the INTEGRAL Satellite (IBIS), the Spectrometer on INTEGRAL (SPI), and the JEM-X (Joint European Monitor for X-rays). Its Optical Monitoring Camera (OMC) provided optical V-band magnitude measurements, complementing the high-energy observations.
European Space Agency, Mereminskiy, 2025, 'M81 deep field: searching for obscured AGNs with INTEGRAL and SRG', 1.0, European Space Agency, https://doi.org/10.57780/esa-i5k59fc
