Search Publications
GRB 231115A—a Magnetar Giant Flare in the M82 Galaxy
Minaev, P. Yu.; Pozanenko, A. S.; Grebenev, S. A. +5 more
The results of a study of the short gamma-ray burst GRB 231115A in the X-ray and gamma-ray ranges are presented, based on data from the INTEGRAL and Fermi space observatories. The source of the burst is localized by the IBIS/ISGRI telescope of INTEGRAL observatory with an accuracy of ${≤}1.\!\!^'5$, it is located in the Cigar Galaxy (M 82). Early …
Deep Hard X-ray Survey of the M81 Field Based on INTEGRAL1 Data
Sazonov, S. Yu.; Mereminskiy, I. A.; Krivonos, R. A.
We have carried out a deep survey of the M81 field in the 25-60 keV energy band based on long-term (2003-2023) INTEGRAL observations. A record sensitivity of 0.16 mCrab at a detection significance of $4σ$ has been achieved in the central part of the field owing to the long accumulated exposure (19.2 Ms). The total area of the survey is 1004 deg${}…
Search for AGNs in Dwarf Galaxies in the the M81 Field with INTEGRAL Data
Sazonov, S. Yu.; Karachentsev, I. D.; Mereminskiy, I. A. +1 more
Using long-term INTEGRAL hard X-ray observations, we have put upper limits on the bolometric luminosity ($L_{\textrm{bol}}\lesssim 10^{41}$ erg s${}^{-1}$) of the nuclei of 72 nearby dwarf galaxies located in the M81 field. This has allowed us to constrain the fraction of galaxies in which the central black hole accretes matter at a rate above 0.1…
SRG/ART-XC Galactic Plane Survey near Galactic Longitude L 20°: Catalog of Sources
Sazonov, S. Yu.; Lutovinov, A. A.; Karasev, D. I. +11 more
We present a catalog of sources detected by the Mikhail Pavlinsky ART-XC telescope onboard the SRG space observatory during the observations of the Galactic plane region near a longitude l~20° (L20 field) in October 2019. The L20 field was observed four times in the scanning mode, which provided a uniform coverage of the sky region with a total ar…
Chromatic Afterglow of GRB 200829A
Minaev, P. Yu.; Pozanenko, A. S.; Volnova, A. A. +16 more
We present the results of our analysis of multiwavelength observations for the long gamma-ray burst GRB 200829A. The burst redshift $z≈ 1.29± 0.04$ has been determined photometrically at the afterglow phase. In gamma rays the event is one of the brightest (in isotropic equivalent), $E_{\textrm{iso}}\gtrsim 10^{54}$ erg. The multicolor light curve …
Search for Evolutionary Changes in the Periods of the Cepheids CEa Cas and CEb Cas
Berdnikov, L. N.; Pastukhova, E. N.; Ikonnikova, N. P. +4 more
For two classical Cepheids, CEa Cas and CEb Cas, members of the open cluster NGC 7790, we have constructed $O-C$ diagrams spanning a time interval of 125 years. The $O-C$ diagrams have the shape of parabolas, which has allowed us for the first time to determine the quadratic light elements and to calculate the rates of evolutionary changes in thei…
Observation of the Second LIGO/Virgo Event Connected with a Binary Neutron Star Merger S190425z in the Gamma-Ray Range
Minaev, P. Yu.; Pozanenko, A. S.; Grebenev, S. A. +1 more
The results of observations of the gravitational-wave (GW) event S190425z recorded by the LIGO/Virgo detectors with the anti-coincidence shield (ACS) of the SPI gamma-ray spectrometer onboard the INTEGRAL observatory are presented. With a high probability (>99%) it was associated with a neutron star (NS) merger in a close binary system. This is…
The {}(\mathbf{7}) Be Abundance in Nova V5668 Sgr Is Consistent with the Theory
Chugai, N. N.; Kudryashov, A. D.
By now the resonance lines of the isotope ${}7$Be have been detected in five novae. The known estimates of the relative abundance of this isotope from the equivalent widths of ${}7$Be II and Ca II lines lead to the conclusion that the ${}7$Be abundance is considerably higher than the predictions of thermonuclear bu…
Changes in the Period of the Population II Cepheid CC Lyr
Berdnikov, L. N.; Pastukhova, E. N.; Yacob, A. M.
The reduction of all the available photometry for the Cepheid CC Lyr has allowed its $O-C$ diagram spanning a time interval of 124 years to be constructed. The data obtained provide evidence for the existence of large random fluctuations in the period ($\varepsilon/P≈ 0.046$). A formal fitting of the $O-C$ residuals has made it possible to estimat…
Search for Evolutionary Changes in the Period the Cepheid ET Vul
Berdnikov, L. N.; Pastukhova, E. N.
The reduction of all the available photometry for the Cepheid ET Vul has allowed its $O-C$ diagram spanning a time interval of 130 years to be constructed. This has made it possible to calculate for the first time the rate of evolutionary decrease in the period, $dP/dt=-426.5(±{29.7})$ s yr${}^{-1}$, in agreement with the results of model calculat…