Raya Dastidar
A5010216241- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Nuclear Physics and Applications
- Neutrino Physics Research
- Color Science and Applications
- Astro and Planetary Science
- Calibration and Measurement Techniques
- Adolescent and Pediatric Healthcare
- Radiative Heat Transfer Studies
- Galaxies: Formation, Evolution, Phenomena
- Particle physics theoretical and experimental studies
- NMR spectroscopy and applications
- Astrophysics and Star Formation Studies
- Seismic Imaging and Inversion Techniques
- Anomaly Detection Techniques and Applications
- Spectroscopy and Laser Applications
- International Science and Diplomacy
- Image Processing Techniques and Applications
- High-Energy Particle Collisions Research
- Hydrocarbon exploration and reservoir analysis
- Spacecraft and Cryogenic Technologies
- Paleopathology and ancient diseases
Universidad Andrés Bello
2022-2025
Millennium Institute of Astrophysics
2022-2025
Indian Institute of Astrophysics
2024
University of Turku
2024
Aryabhatta Research Institute of Observational Sciences
2017-2021
University of Delhi
2017-2021
University of Oklahoma
2006
Abstract Red supergiants may lose significant mass during the final 100–1000 years before core collapse, shaping their circumstellar environment. The supernova (SN) shockwave propagating through this environment forms a shock-swept dense shell that interacts with surrounding material (CSM), generating secondary shocks energise ejecta and power SN nebular phase. In present work, we investigate spectrum of 2023ixf, observed one-year post-explosion (at +363 d) recently commissioned WEAVE...
ABSTRACT We present the semi-analytical light curve modelling of 13 supernovae associated with gamma-ray bursts (GRB-SNe) along two relativistic broad-lined (Ic-BL) SNe without GRB association (SNe 2009bb and 2012ap), considering millisecond magnetars as central-engine-based power sources for these events. The bolometric curves all 15 in our sample are well-regenerated utilizing a χ2-minimization code, MINIM, numerous parameters constrained. median values ejecta mass (Mej), magnetar’s...
Abstract We present the long-term photometric and spectroscopic analysis of a transitioning SN IIn/Ibn from −10.8 d to 150.7 post V-band maximum. 2021foa shows prominent He i lines comparable in strength Hα line around peak, placing between IIn Ibn populations. The spectral comparison that it resembles population at pre-maximum, becomes intermediate SNe post-maximum matches with 1996al. evolution precursor −50 light curve shoulder 17d. peak luminosity color are consistent most our sample....
We investigate the spectroscopic characteristics of intermediate-luminosity Red Transients (ILRTs), a class elusive objects with peak luminosity between that classical novae and standard supernovae. Our goal is to provide stepping stone in path unveiling physical origin these events based on analysis collected datasets. present extensive optical near-infrared (NIR) monitoring four ILRTs, namely NGC 300 2008OT-1, AT 2019abn, 2019ahd 2019udc. First we focus evolution most prominent spectral...
We investigate the photometric characteristics of a sample intermediate-luminosity red transients (ILRTs), class elusive objects with peak luminosity between that classical novae and standard supernovae. Our goal is to provide stepping stone in path reveal physical origin such events, thanks analysis datasets collected. present multi-wavelength follow-up four ILRTs, namely NGC 300 2008OT-1, AT 2019abn, 2019ahd, 2019udc. Through modelling their spectral energy distribution bolometric light...
We conducted a search for luminous outbursts prior to the explosion of Type IIn supernovae (SNe IIn). built sample 27 objects spectroscopically classified as SNe and all located at z < 0.015. Using deep archival SN fields images – taken up nearly 20 yr explosions themselves from transient surveys (PTF, ZTF, DES CHASE) major astronomical observatories (European Southern Observatory, ESO National Optical Astronomy NOAO), we found least one outburst years months before seven IIn, with...
We present the discovery and high-cadence follow-up observations of SN 2018ivc, an unusual Type II supernova that exploded in NGC 1068 (D=10.1 Mpc). The light curve 2018ivc declines piecewise-linearly, changing slope frequently, with four clear changes first 30 days evolution. This rapidly indicates interaction between circumstellar material ejecta plays a significant role Circumstellar is further supported by strong X-ray detection. spectra are evolving dominated hydrogen, helium, calcium...
We present photometric and spectroscopic observations of the type Ibn supernova (SN) 2019uo, second ever SN with flash ionization (He II, C III, N III) features in its early spectra. 2019uo displays a rapid post-peak luminosity decline 0.1 mag d$^{-1}$ similar to most SNe Ibn, but is fainter ($M^V_{max} = -18.30 \pm 0.24$ mag) than typical shows color evolution that places it between Ib extreme Ibn. P-cygni He I spectra which gradually evolves becomes emission dominated post peak. It also...
Abstract We present deep Chandra X-ray observations of two nearby Type Ia supernovae, SN 2017cbv and 2020nlb, which reveal no emission down to a luminosity L X ≲ 5.3 × 10 37 5.4 erg s −1 (0.3–10 keV), respectively, at ∼16–18 days after the explosion. With these limits, we constrain pre-explosion mass-loss rate progenitor system be <?CDATA $\dot{M}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow>...
We present an observational study of the luminous red nova (LRN) AT\,2021biy in nearby galaxy NGC\,4631. The field object was routinely imaged during pre-eruptive stage by synoptic surveys, but transient detected only at a few epochs from $\sim 231$\,days before maximum brightness. LRN outburst monitored with unprecedented cadence both photometrically and spectroscopically. shows short-duration blue peak, bolometric luminosity 1.6 \times 10^{41}$\,erg\,s$^{-1}$, followed longest plateau...
We present optical observations and analysis of a bright type Iax SN~2020udy hosted by NGC 0812. The light curve evolution is similar to other SNe. Analytical modeling the quasi bolometric curves SN 2020udy suggests that 0.08$\pm$0.01 M$_{\odot}$ $^{56}$Ni would have been synthesized during explosion. Spectral features are members class showing weak Si {\sc II} line. late-time spectral sequence mostly dominated Iron Group Elements (IGEs) with broad emission lines. Abundance tomography time...
We present multi-band photometry and spectroscopy of SN 2018cuf, a Type IIP ("P" for plateau) supernova (SN) discovered by the Distance Less Than 40 Mpc survey (DLT40) within 24 hours explosion. 2018cuf appears to be typical SN, with an absolute $V$-band magnitude $-$16.73 $\pm$ 0.32 at maximum decline rate 0.21 0.05 mag/50d during plateau phase. The distance object is constrained 41.8 5.7 using expanding photosphere method. use spectroscopic photometric observations from first year after...
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...
Abstract Astronomical broker systems, such as Automatic Learning for the Rapid Classification of Events (ALeRCE), are currently analyzing hundreds thousands alerts per night, opening up an opportunity to automatically detect anomalous unknown sources. In this work, we present ALeRCE anomaly detector, composed three outlier detection algorithms that aim find transient, periodic, and stochastic sources within Zwicky Transient Facility data stream. Our experimental framework consists...
We present optical photometry and spectroscopy from about a week after explosion to $\sim$272 d of an atypical Type IIP supernova, SN 2015ba, which exploded in the edge-on galaxy IC 1029. 2015ba is luminous event with absolute V-band magnitude -17.1$\pm$0.2 mag at 50 since has long plateau lasting for $\sim$123 d. The distance estimated be 34.8$\pm$0.7 Mpc using expanding photosphere standard candle methods. High-velocity H-Balmer components constant time are observed late-plateau phase...
Abstract We present DELIGHT, or Deep Learning Identification of Galaxy Hosts Transients, a new algorithm designed to automatically and in real time identify the host galaxies extragalactic transients. The proposed receives as input compact, multiresolution images centered at position transient candidate outputs two-dimensional offset vectors that connect with center its predicted host. consists set same number pixels, but progressively larger pixel sizes fields view. A sample 16,791 visually...
We present optical photometric (upto $\sim$410 days since $B$$_{max}$) and spectroscopic $\sim$157 observations of a Type Iax supernova (SN) 2014dt located in M61. SN is one the brightest closest (D $\sim$ 20 Mpc) discovered SN. best matches light curve evolution 2005hk reaches peak magnitude $M$$_B$ $\sim$-18.13$\pm$0.04 mag with $\Delta m_{15}$ $\sim$1.35$\pm 0.06$ mag. The early spectra are similar to other SNe, whereas nebular spectrum at 157 dominated by narrow emission features less...
We present high-cadence ultraviolet (UV), optical, and near-infrared (NIR) data on the luminous Type II-P supernova SN 2017gmr from hours after discovery through first 180 days. does not show signs of narrow, high-ionization emission lines in early optical spectra, yet lightcurve evolution suggests that an extra energy source circumstellar medium (CSM) interaction must be for at least 2 days explosion. Modeling indicates a ~500R$_{\odot}$ progenitor radius, consistent with rather compact red...
We present high-cadence photometric and spectroscopic observations of SN~2020jfo in ultraviolet optical/near-infrared bands starting from $\sim 3$ to 434$ days after the explosion, including earliest data with 10.4\,m GTC. is a hydrogen-rich Type II SN relatively short plateau duration ($67.0 \pm 0.6$ days). When compared other supernovae (SNe) similar or shorter lengths, exhibits fainter peak absolute $V$-band magnitude ($M_V = -16.90 0.34$ mag). shows significant H$\alpha$ absorption phase...
We present an optical photometric and spectroscopic analysis of the fast-declining hydrogen-rich Type II supernova (SN) 2019nyk. The light curve properties SN 2019nyk align well with those other SNe, such as SNe 2013by 2014G. exhibits a peak absolute magnitude −18.09 ± 0.17 mag in V band, followed by rapid decline at 2.84 0.03 (100 d) −1 during recombination phase. early spectra exhibit high-ionisation emission features narrow H Balmer lines, persisting until 4.1 d since explosion,...
We present the semi-analytical light curve modelling of 13 supernovae associated with gamma-ray bursts (GRB-SNe) along two relativistic broad-lined (Ic-BL) SNe without GRBs association (SNe 2009bb and 2012ap), considering millisecond magnetars as central-engine-based power sources for these events. The bolometric curves all 15 in our sample are well-regenerated utilising a $\chi^2-$minimisation code, $\texttt{MINIM}$, numerous parameters constrained. median values ejecta mass...
Abstract We present optical observations and analysis of the bright type Iax supernova SN 2020udy hosted by NGC 0812. The evolution light curve is similar to that other SNe. Analytical modeling quasi-bolometric curves suggests 0.08 ± 0.01 M ⊙ 56 Ni would have been synthesized during explosion. spectral features are those members class, showing a weak Si ii line. late-time sequence mostly dominated iron group elements with broad emission lines. Abundance tomography time series using TARDIS...
We present an analysis of the photometric and spectroscopic dataset type II supernova (SN) 2018ivc in nearby (10 Mpc) galaxy Messier 77. Thanks to our high-cadence data, we observed SN rising very rapidly by nearly three magnitudes five hours (or 18 mag d −1 ). The r -band light curve presents four distinct phases: maximum light, which was reached just one day, followed a first, rapid linear decline short-duration plateau. Finally, long, slower lasted for year. ensuing radio re-brightening,...
We present results of the photometric (from 3 to 509 days past explosion) and spectroscopic (up 230 monitoring campaign He-rich Type IIb supernova (SN) 2015as. The {\it (B-V)} colour evolution SN 2015as closely resemble those 2008ax, suggesting that belongs subgroup does not show early, short-duration peak. light curve reaches $B$-band maximum about 22 after explosion, at an absolute magnitude -16.82 $\pm$ 0.18 mag. At $\sim$ 75 its spectrum transitions from a II Ib. P~Cygni features due He...
We present an extensive ($\sim$ 1200 d) photometric and spectroscopic monitoring of the Type IIn supernova (SN) 2012ab. After a rapid initial rise leading to bright maximum (M$_{R}$ = $-$19.39 mag), light curves show plateau lasting about 2 months followed by steep decline up 100 d. Only in $U$ band is constant same interval. At later phases, remain flatter than $^{56}$Co suggesting increasing contribution interaction between SN ejecta with circumstellar material (CSM). Although heavily...