A5063226126- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- SAS software applications and methods
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Algebraic Geometry and Number Theory
- CCD and CMOS Imaging Sensors
- Redox biology and oxidative stress
- Homotopy and Cohomology in Algebraic Topology
- Particle Accelerators and Free-Electron Lasers
- Microbial metabolism and enzyme function
- Quantum Mechanics and Non-Hermitian Physics
- Catalysts for Methane Reforming
- Biofuel production and bioconversion
- Nuclear Physics and Applications
- Electron Spin Resonance Studies
- Dark Matter and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Advanced Differential Equations and Dynamical Systems
- Neutrino Physics Research
- Global Public Health Policies and Epidemiology
Goddard Space Flight Center
2024-2025
Deleted Institution
2025
Aryabhatta Research Institute of Observational Sciences
2019-2024
Deen Dayal Upadhyaya Gorakhpur University
2020-2024
Artificial Intelligence in Medicine (Canada)
2022
National Institute of Technology Hamirpur
2022
Konkuk University
2019-2021
Benchmark Research (United States)
2018
Noida International University
2018
Institute of Genomics and Integrative Biology
2017
Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions. Bursts long (>2 s) duration produced by the core-collapse massive stars, those short (< 2 merger two neutron stars (NSs). A third class events with hybrid properties was identified, but never conclusively linked to a stellar progenitor. The lack bright supernovae rules out typical explosions, their distance scales prevent sensitive searches for direct signatures progenitor system. Only...
Aims. GRB 190829A (z = 0.0785), detected by Fermi and Swift with two emission episodes separated a quiescent gap of ~40 s, was also observed the H.E.S.S. telescopes at Very-High Energy (VHE). We present 10.4m GTC observations afterglow underlying supernova compare it against similar 180728A discuss implications on physical mechanisms producing these GRBs. Methods. multi-band photometric data along spectroscopic follow-up taken telescope. Together from prompt emission, are used to understand...
Cadmium Zinc Telluride Imager (CZTI) aboard AstroSat has been regularly detecting Gamma-Ray Bursts (GRBs) since its launch in 2015. Its sensitivity to polarization measurements at energies above 100 keV allows CZTI attempt spectro-polarimetric studies of GRBs. Here, we present the first catalog GRB made by during five years operation. This presents time integrated prompt emission 20 GRBs energy range 100-600 keV. The sample includes bright which were detected within an angle 0-60 degree and...
We present the results of a detailed investigation prompt and afterglow emission in HESS detected GRB 190829A. Swift Fermi observations phase this reveal two isolated sub-bursts or episodes, separated by quiescent phase. The energetic spectral properties first episode are stark contrast to second. episode, which has higher peak $\sim 120\:\text{keV}$ low isotropic energy 10^{50}\:\text{erg}$ is an outlier Amati correlation marginally satisfies Yonetoku correlation. However, energetically...
We present radio and optical afterglow observations of the TeV-bright long Gamma Ray Burst (GRB) 190114C at a redshift $z=0.425$, which was detected by MAGIC telescope. Our with ALMA, ATCA, uGMRT were obtained our low frequency observing campaign range from $\sim1$ to $\sim140$ days after burst done three telescopes spanning up $\sim25$ burst. Long term radio/mm reveal complex nature afterglow, does not follow spectral temporal closure relations expected standard model. find that...
Abstract We present a timing study of the gamma and X-ray observations analysis sample bright gamma-ray bursts (GRBs; i.e. GRB 180720B, 181222B, 211211A 220910A), including very long (a.k.a. kilonova candidate). They have been detected observed by Atmosphere-Space Interactions Monitor (ASIM) installed on International Space Station (ISS) Gamma-ray Burst (GBM) on-board Fermi mission. The early (T − T0 ≈ s) high-energy (0.3-20 MeV) ASIM High Energy Detector (HED) (150 keV-30 (BGO) light curves...
The article presents a comprehensive analysis of distributed data architectures in the AdTech industry, focusing on Druid and Redshift. It examines unique capabilities, performance characteristics, optimal use cases for each platform. explores how these handle challenges real-time analytics, batch processing, scalability requirements modern advertising technology environments. Through detailed comparative evaluation, provides insights into selecting appropriate architecture based specific...
ABSTRACT Optical, near-infrared (NIR) photometric and spectroscopic studies, along with the optical imaging polarimetric results for SN 2012au, are presented in this article to constrain nature of progenitor other properties. Well-calibrated multiband data (from –0.2 +413 d since B-band maximum) were used compute bolometric light curve perform semi-analytical light-curve modelling using minim code. A spin-down millisecond magnetar-powered model explains observed evolution 2012au reasonably....
Abstract Multi-pulsed GRB 190530A, detected by the GBM and LAT onboard Fermi, is sixth most fluent burst so far. This paper presents timing, spectral, polarimetric analysis of prompt emission observed using AstroSat Fermi to provide insight into radiation mechanisms. The time-integrated spectrum shows conclusive proof two breaks due peak energy a second lower break. Time-integrated (55.43 ± 21.30 %) as well time-resolved polarization measurements, made Cadmium Zinc Telluride Imager (CZTI)...
We present a detailed prompt emission and early optical afterglow analysis of the two very high energy (VHE) detected bursts GRB 201015A 201216C, their comparison with subset similar bursts. Time-resolved spectral multi-structured 201216C using Bayesian binning algorithm revealed that during entire duration burst, low index ($\alpha_{\rm pt}$) remained below limit synchrotron line death. However, statistically some bins supported additional thermal component. Additionally, evolution...
Abstract The brightest gamma-ray burst (GRB) ever, GRB 221009A, displays ultralong (ULGRB) characteristics, with a prompt emission duration exceeding 1000 s. To constrain the origin and central engine of this unique burst, we analyze its afterglow characteristics compare them to established set similar GRBs. achieve this, statistically examine nearly complete sample Swift-detected GRBs measured redshifts. We categorize bronze, silver, gold by fitting Gaussian function log-normal T 90...
Abstract We investigate the prompt emission and afterglow properties of short-duration gamma-ray burst (sGRB) 130603B another eight sGRB events during 2012–2015, observed by several multiwavelength facilities including Gran Canarias Telescope 10.4 m telescope. Prompt high energy data were obtained INTEGRAL-SPI-ACS, Swift-BAT, Fermi-GBM satellites. The INTEGRAL in range 0.1–10 MeV for 130603B, 140606A, 140930B, 141212A, 151228A do not show any signature extended or precursor activity their...
We present results from extensive broadband follow-up of GRB 210204A over the period thirty days. detect optical flares in afterglow at 7.6 x 10^5 s and 1.1 10^6 after burst: most delayed flaring ever detected a afterglow. At source redshift 0.876, rest-frame delay is 5.8 (6.71 d). investigate possible causes for this conclude that likely cause refreshed shock jet. The prompt emission within range typical long bursts: it shows three disjoint episodes, which all follow correlations. This...
Context. Dark gamma-ray bursts (GRBs) constitute a significant fraction of the GRB population. In this paper, we present multi-wavelength analysis (both prompt emission and afterglow) an intense (3.98 × 10 −5 erg cm −2 using Fermi -Gamma-Ray Burst Monitor) two-episodic 150309A observed early on until ∼114 days post burst. Despite strong emission, no optical afterglow was detected for However, discovered near-infrared (NIR) ( K S -band), ∼5.2 h burst, with CIRCE instrument mounted at 10.4 m...
ABSTRACT We report the discovery of Swift J221951−484240 (hereafter: J221951), a luminous slow-evolving blue transient that was detected by Neil Gehrels Observatory Ultraviolet/Optical Telescope (Swift/UVOT) during follow-up gravitational wave alert S190930t, to which it is unrelated. Swift/UVOT photometry shows UV spectral energy distribution be well modelled slowly shrinking blackbody with an approximately constant temperature T ∼ 2.5 × 104 K. At redshift z = 0.5205, J221951 had peak...
India has been actively involved in the follow-up observations of optical afterglows gamma-ray bursts (GRBs) for more than two decades, using country’s meter-class facilities such as 1.04m Sampurnanand Telescope, 1.3m Devasthal Fast Optical 2.01 m Himalayan Chandra Telescope along with many others country, utilizing longitudinal advantage place. However, since 2016, Indian astronomers have embarked on a new era exploration by largest telescope, 3.6-m (DOT) at Observatory ARIES Nainital. This...
Abstract This paper presents data and analysis of SN 2010kd, a low-redshift ( z = 0.101) H-deficient superluminous supernova (SLSN), based on ultraviolet/optical photometry optical spectroscopy spanning between −28 +194 days relative to B -band maximum light. The light-curve comparison 2010kd with subset well-studied SLSNe I at comparable redshifts indicates that it is slow-decaying PTF12dam-like SLSN. Analytical modeling using the Minim code suggests bolometric light curve favors...
We present and perform a detailed analysis of multi-wavelength observations GRB 140102A, an optical bright with observed reverse shock (RS) signature.Observations this were acquired the BOOTES-4 robotic telescope, Fermi, Swift missions.Time-resolved spectroscopy prompt emission shows that changes to peak energy ( p ) tracks intensity low-energy spectral index seems follow for first episode, whereas tracking behavior is less clear during second episode.The fit afterglow light curves early can...
We investigate the observational properties of a hydrogen-deficient superluminous supernova (SLSN) SN 2020ank (at z = 0.2485), with help early phase observations carried out between $-$21 and +52 d since $g$-band maximum. Photometrically, is one brightest SLSN ($M_{g,peak}$ $\sim$ $-$21.84 $\pm$ 0.10 mag), having fast pre-peak rising post-peak decaying rates. The bolometric light curve exhibits higher peak luminosity ($L_{max}$) $\sim$(3.9 0.7) $\times$ 10$^{44}$ erg s$^{-1}$ appears to be...