Zobrazeno 1 - 10
of 112
pro vyhledávání: '"Gulab C Dewangan"'
Autor:
Swadesh Chand, Gulab C. Dewangan, Andrzej A. Zdziarski, Dipankar Bhattacharya, N. P. S. Mithun, Santosh V. Vadawale
Publikováno v:
The Astrophysical Journal, Vol 972, Iss 1, p 20 (2024)
We perform broadband (0.7–100 keV) spectral analysis of five hard state observations of the low-mass black hole X-ray binary GX 339–4 taken by AstroSat during the rising phase of three outbursts from 2019 to 2022. We find that the outburst in 202
Externí odkaz:
https://doaj.org/article/17ae9cb4ecc645fb90ae84e1597f1aa1
Autor:
Srimanta Banerjee, Gulab C. Dewangan, Christian Knigge, Maria Georganti, Poshak Gandhi, N. P. S. Mithun, Payaswini Saikia, Dipankar Bhattacharya, David M. Russell, Fraser Lewis, Andrzej A. Zdziarski
Publikováno v:
The Astrophysical Journal, Vol 964, Iss 2, p 189 (2024)
We present a comprehensive multiwavelength spectral analysis of the black hole (BH) X-ray binary MAXI J1820+070 during its 2018 outburst, utilizing AstroSat far-UV, soft X-ray, and hard X-ray data, along with (quasi-)simultaneous optical and X-ray da
Externí odkaz:
https://doaj.org/article/92dfc355b4fc486aa80a0959da6de84c
Publikováno v:
Astronomische Nachrichten. 344
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::f619c0e2a7d6bf0677948d218a5c2382
https://doi.org/10.1002/asna.20230042
https://doi.org/10.1002/asna.20230042
Autor:
Max W J Beard, Ian M McHardy, Kavita Kumari, Gulab C Dewangan, Iossif Papadakis, Dipankar Bhattacharya, Kulinder Pal Singh, Daniel Kynoch, Mayukh Pahari
We present a 140ks observation of NGC 4593 with XMM-Newton providing simultaneous and continuous PN X-ray and OM UV (UVW1 2910\AA) lightcurves which sample short-timescale variations better than previous observations. These observations were simultan
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4799eb9a7e45d46f11c5aa6d3d370ffc
http://arxiv.org/abs/2211.10229
http://arxiv.org/abs/2211.10229
Autor:
Savithri H. Ezhikode, Amit Shukla, Gulab C. Dewangan, Pramod K. Pawar, Sushmita Agarwal, Blesson Mathew, Akhil Krishna R.
The $\gamma-$ray emission from flat-spectrum radio quasars (FSRQs) is thought to be dominated by the inverse Compton scattering of the external sources of photon fields, e.g., accretion disk, broad-line region (BLR), and torus. FSRQs show strong opti
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bd4704ea80dbf61b86cea23451137ea7
http://arxiv.org/abs/2209.13574
http://arxiv.org/abs/2209.13574
Autor:
Alex G Markowitz, Krzysztof Nalewajko, Gopal Bhatta, Gulab C Dewangan, Sunil Chandra, Daniela Dorner, Bernd Schleicher, Urszula Pajdosz-Śmierciak, Łukasz Stawarz, Staszek Zola, Michał Ostrowski, Daniele Carosati, Saikruba Krishnan, Rumen Bachev, Erika Benítez, Kosmas Gazeas, David Hiriart, Shao-Ming Hu, Valeri Larionov, Alessandro Marchini, Katsura Matsumoto, A A Nikiforova, Tapio Pursimo, Claudia M Raiteri, Daniel E Reichart, Diego Rodriguez, Evgeni Semkov, Anton Strigachev, Yuki Sugiura, Massimo Villata, James R Webb, Axel Arbet-Engels, Dominik Baack, Matteo Balbo, Adrian Biland, Thomas Bretz, Jens Buss, Laura Eisenberger, Dominik Elsaesser, Dorothee Hildebrand, Roman Iotov, Adelina Kalenski, Karl Mannheim, Alison Mitchell, Dominik Neise, Maximilian Noethe, Aleksander Paravac, Wolfgang Rhode, Vitalii Sliusar, Roland Walter
The study of short-term variability properties in AGN jets has the potential to shed light on their particle acceleration and emission mechanisms. We report results from a four-day coordinated multi-wavelength campaign on the highly-peaked blazar (HB
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::276b4fb77984a9025dafc14f4ea505ee
http://arxiv.org/abs/2206.03874
http://arxiv.org/abs/2206.03874
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 492:3041-3046
The hard X-ray spectral index of some AGN has been observed to steepen with the source flux. This has been interpreted in a Comptonization scenario, where an increase in the soft flux decreases the temperature of the corona, leading to steepening of
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::401f770fbf242f437e4357161cb5ce32
https://doi.org/10.1093/mnras/staa067
https://doi.org/10.1093/mnras/staa067
Autor:
Ritesh Ghosh, Sibasish Laha, Kunal Deshmukh, Varun Bhalerao, Gulab C. Dewangan, Ritaban Chatterjee
We have studied the nature and origin of the soft X-ray excess detected in the interesting changing-look AGN (CLAGN) Mrk~590 using two decades of multi-wavelength observations from \xmm{}, \suzaku{}, \swift{} and \nustar{}. In the light of vanishing
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bc6ebcb033e00cca2e17f263c88d70cc
Autor:
Gulab C. Dewangan, Rathin Sarma, V. Jithesh, Amit Pathak, Samuzal Barua, Biman J. Medhi, Ranjeev Misra
We report flux-resolved spectroscopic analysis of the active galactic nucleus (AGN) ESO 103--035 using \textit{NuSTAR} observations. Following an earlier work, we fit the spectra using a thermal Comptonization model with a relativistic reflection com
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::78981b1ab1ddb5b5e685d951b1f4284d
http://arxiv.org/abs/2108.04288
http://arxiv.org/abs/2108.04288
Autor:
Alok C. Gupta, Rathin Adhikari, H. Nandan, Oluwashina Adegoke, Gulab C. Dewangan, Main Pal, Sachindra Naik, Neeraj Kumari, Piyush Tripathi, Pankaj Kushwaha, K. P. Singh
Publikováno v:
Journal of Astrophysics and Astronomy. 42
We present a detailed timing and spectral study of an extremely variable narrow-line Seyfert 1 galaxy NGC 4748 using observations in the year 2017 and 2014 performed with AstroSat and XMM-Newton, respectively. Both observations show extremely variabl
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::3e962a225398d216dfac8539502927d7
https://doi.org/10.1007/s12036-021-09719-1
https://doi.org/10.1007/s12036-021-09719-1