8 results on '"Pandey, Shashi Bhushan"'
Search Results
2. Core-collapse supernova from a possible progenitor star of 100 M⊙
- Author
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ARYAN, AMAR, PANDEY, SHASHI BHUSHAN, YADAV, ABHAY PRATAP, KUMAR, AMIT, GUPTA, RAHUL, and TIWARI, SUGRIVA NATH
- Published
- 2022
- Full Text
- View/download PDF
3. Evolution of rotating 25 M⊙ Population III star: physical properties and resulting supernovae.
- Author
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Aryan, Amar, Pandey, Shashi Bhushan, Gupta, Rahul, and Ror, Amit Kumar
- Subjects
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SUPERNOVAE , *STELLAR winds , *STELLAR populations , *STELLAR rotation , *FLAMMABLE limits - Abstract
In this letter, we report the outcomes of 1D modelling of a rotating 25 M⊙ zero-age main sequence Population III (Pop III) star up to the stage of the onset of core collapse. Rapidly rotating models display violent and sporadic mass-losses after the main-sequence stage. In comparison to the solar metallicity model, Pop III models show very small pre-supernova radii. Further, with models at the stage of the onset of core collapse, we simulate the hydrodynamic simulations of resulting supernovae. Depending upon the mass-losses due to corresponding rotations and stellar winds, the resulting supernovae span a class from weak Type II to Type Ib/c. We find that the absolute magnitudes of the core-collapse supernovae resulting from Pop III stars are much fainter than that resulting from a solar metallicity star. From our simulation results, we also conclude that within the considered limits of explosion energies and nickel masses, these transient events are very faint, making it difficult for them to be detected at high-redshifts. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Supernovae study: Context of the 4-m International Liquid Mirror Telescope
- Author
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Surdej, Jean, Kumar, Brajesh, Pandey, Shashi Bhushan, Pandey, Kanhaiya Lal, and Anupama, Gadiyara Chakrapani
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instrumentation ,Physics ,Multidisciplinary ,astrophysics ,observatoires ,supernovae ,observatories ,Liquid mirror telescope ,Astronomy ,Context (language use) ,astronomy ,Supernova ,astronomie ,Instrumentation (computer programming) ,astrophysique - Abstract
The upcoming 4-m International Liquid Mirror Telescope (ILMT) facility will perform deep imaging (in single scan g’~22 mag) of a narrow strip of sky each clear night in the Time Delayed Integration mode. A cadence of one day observation will provide unique opportunities to discover different types of supernovae (SNe) along with many other types of variable sources. We present the approach to discover SNe with the 4-m ILMT and discuss the follow-up strategy in the context of other existing observational facilities. The advantages of liquid mirror telescope observations over the traditional glass mirror telescopes are also discussed.
- Published
- 2018
- Full Text
- View/download PDF
5. A Peculiar Subclass of Type Ia Supernovae a.k.a. Type Iax
- Author
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Kumar, Brajesh, Kumar, Brijesh, Pandey, Shashi Bhushan, Misra, Kuntal, Anupama, Gadiyara Chakrapani, Sahu, Devendra Kumar, Chakradhari, Nand Kumar, Singh, Mridweeka, Dastidar, Raya, Gangopadhyay, Anjasha, Bose, Subhash, and Srivastav, Shubham
- Subjects
Physics ,spectroscopy ,Multidisciplinary ,astrophysics ,photometry ,supernovae ,Astrophysics ,extragalactique ,spectroscopie ,Subclass ,astronomy ,Photometry (optics) ,Supernova ,photométrie ,astronomie ,Spectroscopy ,astrophysique ,extragalactic - Abstract
We present optical photometric (upto 410 days since Bmax) and spectroscopic (upto 235 days since Bmax) observations of a type Iax supernova SN 2014dt located in M61. The broad band light curves follow a linear decline upto 100 days after which a significant flattening is seen in the late-time (beyond 150 days) light curves of SN 2014dt. SN 2014dt best matches the light curve evolution of SN 2005hk and reaches a peak magnitude of MB -18.12±0.04 with m15 1.35±0.06 mag. The earliest spectrum at 23 days is dominated by FeII and CoII lines with the absence of the Si II 6150 Å line. Using the peak bolometric luminosity we estimate a 56Ni mass of 0.14 M in the case of SN 2005hk and the striking similarity between SN 2014dt and SN 2005hk implies that a comparable amount of 56Ni would have been synthesized in the explosion of SN 2014dt. There are several explosion scenarios proposed for these peculiar events. Being one of the brightest and closest SN, SN 2014dt is an ideal candidate for long term monitoring. Late phase observations are very essential to understand the progenitor system and the actual explosion scenario for these events.
- Published
- 2018
- Full Text
- View/download PDF
6. Light Curve and Spectral Evolution of Type IIb Supernovae
- Author
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Kumar, Brijesh, Pandey, Shashi Bhushan, Misra, Kuntal, Anupama, Gadiyara Chakrapani, Sahu, Devendra Kumar, Singh, Mridweeka, Dastidar, Raya, Gangopadhyay, Anjasha, and Pastorello, Andrea
- Subjects
Physics ,Multidisciplinary ,astrophysics ,photometry ,supernovae ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,extragalactique ,Light curve ,astronomy ,Supernova ,Photometry (astronomy) ,Type iib ,Spectral evolution ,photométrie ,Astrophysics::Solar and Stellar Astrophysics ,astronomie ,Astrophysics::Earth and Planetary Astrophysics ,astrophysique ,extragalactic ,Astrophysics::Galaxy Astrophysics - Abstract
Stripped-Envelope Supernovae constitute the sub-class of core-collapse supernovae that strip off their outer hydrogen envelope due to high stellar winds or due to interaction with a binary companion where mass transfer occurs as a result of Roche lobe overflow. We present here the photometric and spectroscopic analysis of a member of this class : SN 2015as classified as a type IIb supernova. Light curve features are similar to those of SN 2011fu while spectroscopic features are quite similar to those of SN 2008ax and SN 2011dh. Early epoch spectra have been modelled with SYN++ which indicates a photospheric velocity of 8500 km sec-1 and temperature of 6500K. Spectroscopic lines show transitioning from H to He features confirming it to be a type IIb supernova. Prominent oxygen and calcium emission features are indicative of the asymmetry of the ejecta. We also estimate the signal to noise ratio of the 3.6m telescope data. This telescope is located at ARIES, Devasthal, Nainital at an altitude of 2450m. We also show the comparison plots of spectra taken with a 2m and 4m class telescopes to enlighten the importance of spectral features displayed by bigger diameter telescopes.
- Published
- 2018
7. Core-collapse SNe of type IIP and their progenitors: The case study of PNV J01315945+3328458
- Author
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Kumar, Brijesh, Pandey, Shashi Bhushan, Misra, Kuntal, Anupama, Gadiyara Chakrapani, Sahu, Devendra Kumar, Singh, Mridweeka, Dastidar, Raya, and Gangopadhyay, Anjasha
- Subjects
Physics ,Multidisciplinary ,astrophysics ,photometry ,supernovae ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,extragalactique ,astronomy ,Supernova ,photométrie ,Astrophysics::Solar and Stellar Astrophysics ,astronomie ,Astrophysics::Galaxy Astrophysics ,astrophysique ,extragalactic - Abstract
The type II supernovae (SNe) are hydrogen-rich cosmic explosions resulting from the collapse of massive stars. The impetus of studying individual events arises from its cosmological importance and the diverse understanding of the evolution and explosion mechanism of such events. In this work, we present the preliminary photometric and spectroscopic analysis of a recent type IIP explosion, PNV J01315945+3328458 in the galaxy NGC 582. While the initial phases of these energetic events are bright enough to be observed with the 1-2m class telescopes, the supernovae fade below the detection limit of these telescopes in the nebular phase. In addition, the class of sub-luminous events with Mv -15 or the events occurring at higher redshift, fade below the detection limit of these telescopes very early in their evolution. Large aperture telescopes like the newly installed 3.6m Devasthal Optical Telescope (DOT) will ensure a longer coverage of such events and also to probe deeper into the Universe. With the 3.6m telescope installed in Devasthal (DOT), we plan to study the progenitor environment of CCSNe to infer the metallicity at the explosion site.
- Published
- 2018
- Full Text
- View/download PDF
8. Photometric and spectroscopic evolution of the peculiar Type IIn SN 2012ab.
- Author
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Gangopadhyay, Anjasha, Turatto, Massimo, Benetti, Stefano, Misra, Kuntal, Kumar, Brajesh, Cappellaro, Enrico, Pastorello, Andrea, Tomasella, Lina, Vanni, Sabrina, Fiore, Achille, Morales-Garoffolo, A, Elias-Rosa, Nancy, Singh, Mridweeka, Dastidar, Raya, Ochner, Paolo, Tartaglia, Leonardo, Kumar, Brijesh, and Pandey, Shashi Bhushan
- Subjects
LIGHT curves ,SEYFERT galaxies ,SUPERNOVAE ,SPECIAL effects in lighting - Abstract
We present an extensive (∼1200 d) photometric and spectroscopic monitoring of the Type IIn supernova (SN) 2012ab. After a rapid initial rise leading to a bright maximum (M
R = −19.39 mag), the light curves show a plateau lasting about 2 months followed by a steep decline up to about 100 d. Only in the U band, the decline is constant in the same interval. At later phases, the light curves remain flatter than the56 Co decline, suggesting the increasing contribution of the interaction between SN ejecta with circumstellar material (CSM). Although heavily contaminated by emission lines of the host galaxy, the early spectral sequence (until 32 d) shows persistent narrow emissions, indicative of slow unshocked CSM, and the emergence of broad Balmer lines of hydrogen with P-Cygni profiles over a blue continuum, arising from a fast expanding SN ejecta. From about 2 months to ∼1200 d, the P-Cygni profiles are overcome by intermediate width emissions [full width at half-maximum (FWHM) ∼6000 km s−1 ], produced in the shocked region due to interaction. On the red wing, a red bump appears after 76 d, likely a signature of the onset of interaction of the receding ejecta with the CSM. The presence of fast material both approaching and then receding is suggestive that we are observing the SN along the axis of a jet-like ejection in a cavity devoid of or uninterrupted by CSM in the innermost regions. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
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