A5023573888- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Astronomical Observations and Instrumentation
- Solar Radiation and Photovoltaics
- Stellar, planetary, and galactic studies
- Radiation Therapy and Dosimetry
- Geomagnetism and Paleomagnetism Studies
- Mechanics and Biomechanics Studies
- Particle accelerators and beam dynamics
- High-pressure geophysics and materials
- Astrophysics and Star Formation Studies
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
Raman Research Institute
2024
Indian Institute of Science Education and Research, Bhopal
2024
Max Planck Institute for Radio Astronomy
2017-2022
ABSTRACT The stellar binary system LS I +61°303, composed of a compact object in an eccentric orbit around B0 Ve star, emits from radio up to γ-ray energies. orbital modulation spectral index, X-ray, and GeV data suggests the presence two peaks. This two-peaked profile is line with accretion theory predicting accretion–ejection events for +61°303 along 26.5 d orbit. However, existing multiwavelength are not simultaneous. In this paper, we report results campaign covering radio, observations...
Abstract LS I +61°303 is a γ-ray emitting X-ray binary with periodic radio outbursts time-scales of one month. Previous observations have revealed microflares superimposed on these large periods ranging from few minutes to hours. This makes +61°303, along Cyg X-1, the only TeV exhibiting microflares. To further investigate this microflaring activity in we observed source 100-m Effelsberg telescope at 4.85, 8.35 and 10.45 GHz, performed timing analysis obtained data. Radio oscillations 15 h...
LS I +61$^{\circ}$303 is an X-ray binary with a radio outburst every ~27 days. Previous studies of the stellar system revealed microflares superimposed on large outburst. We present here new observations at 2.2 GHz Westerbork Synthesis Radio Telescope (WSRT). Using various timing analysis methods we find significant Quasi-Periodic Oscillations (QPOs) 55 minutes stable over duration 4 also use archival data obtained from Suzaku satellite wavelengths. report for first time QPOs about 2 hours...
Observations of the X-ray binary system Her X-1 by AstroSat Soft Telescope 1 (SXT) were carried out in 2020 through 2023 with goals measuring spectrum changes 35-day disk rotation phase and eclipses at different phases. The four multi-day long observations scheduled during: turn-on to Main High (MH) MH rise; state; Short (SH) Low State (LS). was determined using monitoring Swift Burst Alert (BAT). Nine observed a range phases, least one eclipse during each observation. Data dips separated...
Observations of the X-ray binary system Her X-1 by AstroSat Soft Telescope (SXT) were carried out in 2020 through 2023 with goals measuring spectrum changes 35-day disk precession phase and eclipses at different phases. exhibits a regular flux modulation period ≃35 days intensity levels various phases (called “states”). The four multi-day long observations scheduled to cover most these states. Each was determined using monitoring Swift Burst Alert (BAT). Nine observed range phases, least one...
Abstract A new giant outburst of the Be X-ray binary RX J0520.5-6932 was detected and subsequently observed with several space-borne ground-based instruments. This study presents a comprehensive analysis optical data, focusing on spectral timing characteristics selected observations. joint fit spectra from simultaneous observations performed by telescope (XRT) Neil Gehrels Swift Observatory (Swift) Nuclear Spectroscopic Telescope ARray (NuSTAR) provides broadband parameter constraints,...
The high-mass X-ray binary LS I +61°303 exhibits variability in its radio and emissions, ranging from minute to hour time-scales. At such short time-scales, not much is known about the possible correlations between these two emissions this source, which might offer hints their origin. Here, we study relationship using simultaneous monitoring. We present new observations Arcminute Microkelvin Imager Large Array telescope at frequency bands, 13-15.5 15.5-18 GHz. also describe performed...
There is theoretical and observational evidence that the jet core position changes with frequency. However, for a given frequency may vary time in case of flares or precessing jet. In this work, we want to explore as function frequency, magnetic field alignment, relativistic electron density, inclination angle. We use physical model synchrotron-emitting Two cases are analysed, namely parallel perpendicular axis. The evolution related spectrum monitored over radio band. find smaller angle...
The high-mass X-ray binary LS I +61°303 is detected from radio up to very high energy γ-rays. source consists of a Be star and compact object in an eccentric orbit. Observations have shown evidence for microflares superimposed on larger outbursts. We observed the decaying phase one large outburst with 100-m telescope Effelsberg at 5, 8, 10 GHz. microflaring activity periodicities 9.5 14.9 hours. discuss possible physical processes behind these quasi-periodic oscillations.