A5027552244- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Mechanics and Biomechanics Studies
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- High-pressure geophysics and materials
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Heat Transfer Mechanisms
- Relativity and Gravitational Theory
- Scientific Measurement and Uncertainty Evaluation
- Geophysics and Sensor Technology
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- SAS software applications and methods
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Semiconductor Detectors and Materials
- Spacecraft and Cryogenic Technologies
- Experimental and Theoretical Physics Studies
- Magnetic confinement fusion research
- Electron and X-Ray Spectroscopy Techniques
Lomonosov Moscow State University
2013-2024
Université Savoie Mont Blanc
2018-2020
Centre National de la Recherche Scientifique
2018-2020
Laboratoire d'Annecy-le-Vieux de Physique Théorique
2017-2020
All Russian Institute for Scientific and Technical Information
2019-2020
Moscow State University
2010
Results of simultaneous INTEGRAL and optical observations the galactic microquasar SS433 in May 2003 /RXTE March 2004 are presented. Persistent precessional variability with a maximum to minimum uneclipsed hard X-ray flux ratio ∼4 is discovered. The 18–60 keV eclipse found be phase near infrared eclipses. orbital observed by at least two times deeper apparently wider than soft band. broadband 2–100 spectrum simultaneously detected RXTE/INTEGRAL can explained bremsstrahlung emission from...
We present the results of a comprehensive investigation on evolution spectral and timing properties Galactic black hole candidate 4U 1630–47 during its transitions. In particular, we show how scaling correlation photon index Comptonized component Γ with low-frequency quasi-periodic oscillations (QPOs), νL, mass accretion rate, , can be applied to inclination angle estimates. analyze transition episodes observed Rossi X-Ray Timing Explorer BeppoSAX satellites. find that broadband X-ray energy...
We present an analysis of the spectral and timing properties X-ray emission from Z-source Sco~X-1 during its evolution between Horizontal (HB) Flaring(FB) branches observed with RXTE 1996 -- 2002 period. find that broad-band (3 - 250 keV) energy spectra all states can be adequately reproduced by a model, consisting two Comptonized components iron-line. suggest seed photons kT_s1~0.7 keV coming disk temperature kT_s2~1.8 neutron star (NS) are each upscattered hot electrons "Compton cloud"...
We present a study of the correlations between spectral, timing properties and mass accretion rate observed in X-rays from Galactic Black Hole (BH) binary GRS 1915+105 during transition hard soft states. analyze all episodes this source with RXTE, coordinated Ryle Radio Telescope (RT) observations. show that broad-band energy spectra these spectral states can be adequately presented by two Bulk Motion Comptonization (BMC) components: component (BMC1, photon index Gamma_1=1.7-3.0) turnover at...
We present an analysis of the spectral properties observed in X-rays from Neutron Star X-ray binary 4U~1728-34 during transitions between low and high luminosity states when electron temperature kT_e Compton cloud monotonically decreases 15 to 2.5 keV. analyze transition episodes this source with BeppoSAX RXTE. find that broad-band energy spectra all can be modeled by a combination thermal (black body-like) component, Comptonized component (which we herein denote COMPTB) Gaussian component....
We present an analysis of the spectral and timing properties observed in X-rays from neutron star binary GX~3+1. analyze all observations this source obtained with RXTE BeppoSAX satellites. find that X-ray broad-band energy spectra during these transitions can be adequately reproduced by a composition low-temperature blackbody component, Comptonized component (COMPTB) Gaussian component. argue electron temperature kT_e Compton cloud monotonically increases 2.3 keV to 4.5 keV, when GX~3+1...
We present an analysis of the X-ray spectral properties observed from black hole candidate (BHC) binary SS~433. have analyzed RXTE data this source, coordinated with Green Bank Interferometer/RATAN-600. show that SS~433 undergoes a transition low hard state (LHS) to intermediate (IS). broad-band energy spectra during all states are well fit by sum so called ``Bulk Motion Comptonization (BMC) component'' and two (broad narrow) Gaussians for continuum line emissions respectively. In addition...
We show an analysis of the spectral and timing properties X-ray radiation from Z-source GX 340+0 during its evolution when electron temperature transition layer (TL) kTe monotonically decreases 21 to 3 keV. analyze episodes observed with BeppoSAX RXTE. reveal that broadband energy spectra all states can be reproduced by a physical model composed soft Blackbody component two Comptonized components (both due presence TL upscatters both seed photons Ts1 ≲ 1 keV coming disk (first Comptb1), Ts2...
We report the results of Swift and Chandra observations an ultra-luminous X-ray source, ULX-1 in M101. show strong observational evidence that M101 undergoes spectral transitions from low/hard state to high/soft during these observations. The spectra are well fitted by so-called bulk motion Comptonization (BMC) model for all states. have established photon index (\Gamma) saturation level, \Gamma_{sat}=2.8 +/- 0.1, \Gamma vs. mass accretion rate (\dot M) correlation. This \Gamma-\dot M...
We present a study of outburst activity in the BL Lacertae source OJ 287, which has been observed extensively with X-ray telescope (XRT) on board Neil Gehrels Swift Observatory. demonstrate that results our analysis flaring using /XRT data allow for key characteristics 287 secondary to be refined (its nature and mass). discover energy spectra all spectral states can fitted XSPEC bulk motion Comptonization (BMC) model. As result we find photon index BMC model, Γ, correlates mass accretion...
We analyze the X-ray spectra and their timing properties of compact binary 4U~1820-30. establish a number spectral transitions in this source seen with BeppoSAX RXTE. During RXTE observations (1996 -- 2009), were approximately 75% its time soft state making lower banana upper combined long-term low-high transitions. reveal that all 4U~1820-30 are fit by composition thermal (blackbody) component, Comptonization component (COMPTB) Gaussian-line component. Thus using analysis we find photon...
We present an analysis of the spectral properties observed in X-rays from active galactic nucleus BL Lacertae using RXTE, Suzaku, ASCA, BeppoSAX, and Swift observations. The total time covered by these observations is approximately 20 yr. show strong observational evidence that this source undergoes X-ray transitions low hard state (LHS) through intermediate (IS) to high soft (HSS) during During RXTE (1997–2001, 180 ks, for a 145 datasets), was ~75%, ~20% only ~5% IS, LHS, HSS, respectively....
We analyze the X-ray spectra of atoll 4U 1705–44 when source undergoes island−banana state transition. use RXTE and BeppoSAX observations for this analysis. demonstrate that broadband energy spectral distributions all evolutinary states can be fitted by a model consisting two Comptonized components. One arises from seed photons coming neutron star (NS) atmosphere at temperature keV (herein Comptb1), second results 1.1–1.3 disk Comptb2). found we needed to add low-temperature blackbody an...
ABSTRACT We present an X-ray spectral analysis of the high-mass binary 4U 1700-37 during its hard-soft state evolution. use Beppo SAX, Suzaku , and Rossi Timing Explorer observations for this investigation. argue that broadband spectra all states can be adequately reproduced by a model consisting low-temperature blackbody component, two Comptonized components which are both due to presence Compton cloud (CC) up-scatters seed photons T s 1 ≲ 1.4 keV 2 < keV, iron-line component. Using...
We present our analysis of the extensive monitoring SS433 by RXTE observatory collected over period 1996–2005. The difference between energy spectra taken at different precessional and orbital phases shows presence strong photoabsorption ( cm-2) near optical star, probably due to its powerful, dense wind. Therefore size secondary deduced from X-ray eclipses might be significantly larger than Roche lobe size, which must into account when evaluating mass ratio eclipses. Assuming that a...
A tidal disruption event (TDE) is an astronomical phenomenon in which a previously dormant black hole (BH) destroys star passing too close to its central part. We analyzed the flaring episode detected from TDE sources, Swift~J1644+57 and Swift J2058+05 using RXTE, Suzaku data. The spectra are well fitted by so called Bulk Motion Comptonization model for best-fit photon index Gamma varies 1.1 1.8. have firmly established saturation of versus mass accretion rate at Gamma_{sat} about 1.7 --...
Precise measurements of black hole (BH) masses are necessary to understand the coevolution these sources and their host galaxies. Sometimes in center a galaxy, there is not one but two BHs. The BH duality quasar nucleus SDSS J075217.84 + 193542.2 (herein referred as J0752) was recently proposed based on observed strict periodicity optical emission from source. We tested this assumption using X-ray observations obtained Swift/XRT (2008–2010). fitted J075217 spectrum Comptonization model...
We present our analysis of X-ray spectral properties observed from the Seyfrert 1 galactic nucleus NGC~7469 using RXTE and ASCA observations. demonstrate strong observational evidence that undergoes transitions low hard state (LHS) to intermediate (IS) during these The observations (1996--2009) show source was in IS ~ 75 % time only, 25 LHS. spectra are well fitted by so-called bulk motion Comptonization (BMC) model for all states. have established photon index saturation level,...
Observations of SS433 by INTEGRAL carried out in March -- May 2003 are presented. is evidently detected on the images corresponding sky region energy bands 25-50 and 50-100 keV. The precessional variability hard X-ray flux clearly seen. eclipse caused binary orbital motion also detected. A possible origin continuum briefly discussed.
We present the discovery of correlations between X-ray spectral (photon) index and mass accretion rate observed in active galactic nuclei (AGNs) 3C 454.3 M 87. analyzed transition episodes these AGNs using Chandra , Swift Suzaku Beppo SAX, ASCA RXTE data. applied a scaling technique for black hole (BH) evaluation which uses correlation photon normalization seed (disk) component is proportional to rate. developed an analytical model that shows BH emergent spectrum undergoes evolution from...
We report the results of Swift/XRT observations (2008-2015) a hyper-luminous X-ray source, ESO 243-49 HLX-1. found strong observational evidence that HLX-1 underwent spectral transitions from low/hard state to high/soft during these observations. The spectra are well fitted by so-{called} bulk motion Comptonization model for all states. have established photon index Gamma saturation level, Gamma_{sat}$=3.0+/-0.1, in correlation versus mass accretion rate dot M. This Gamma-dot M allows us...
The multi-wavelength outburst activity in the recently discovered X-ray binary transient MAXI J1348–630 has sparked a great deal of controversy about characteristics this and questions around whether source contains black hole (BH). Here, we present results our analysis using Swift /XRT data. We find that energy spectra all spectral states can be modeled combination Comptonization Gaussian iron-line components. In addition, show photon index, Γ, is correlated with mass accretion rate, Ṁ . Γ...
We present a discovery of the correlation between X-ray spectral (photon) index and mass accretion rate observed in AGN NGC 4051. analyzed transition episodes 4051 using XMM/Newton, Suzaku RXTE. applied scaling technique for black hole (BH) evaluation which uses photon normalization seed (disk) component, is proportional to rate. developed an analytical model that shows BH emergent spectrum undergoes evolution from lower higher values depending on disk. considered Cygnus X-1 GRO~J1550-564 as...
We present a study of the correlations between spectral, timing properties and mass accretion rate observed in X‐rays from eight Galactic Black Hole (BH) binaries during transition hard soft states. analyze all episodes X‐ray sources with Rossi Timing Explorer (RXTE). show that broad‐band energy spectra these spectral states can be adequately presented by Bulk Motion Comptonization (BMC) model. also observable index normalization disk "seed" component. The use normalization, which is...