IIA Institutional Repository: Recent submissions

  • Some glimpses of the plasma processes involved in power spectra of radio pulsars 
    Roy, Tridib (Oxford University Press on behalf of the Royal Astronomical Society, 2021-07)
    Although more than a half-century since pulsar discovery, the field of pulsar astronomy has attained an unprecedented level of success and has opened several windows in astronomy, very few theories have been put forwarded ...
  • Jet properties of XTE J1752−223 during its 2009–2010 outburst 
    Debnath, Dipak; Chatterjee, Kaushik; Chatterjee, Debjit; Jana, Arghajit; Chakrabarti, S. K (Oxford University Press on behalf of the Royal Astronomical Society, 2021-07)
    Galactic short orbital period black hole candidate (BHC) XTE J1752−223 was discovered on 2009 October 21 by the Rossi X-ray Timing Explorer (RXTE). We study the spectral properties of this outburst using transonic flow ...
  • Appearance versus disappearance of broad absorption line troughs in quasars 
    Mishra, Sapna; Vivek, M; Chand, Hum; Joshi, Ravi (Oxford University Press on behalf of the Royal Astronomical Society, 2021-07)
    We present a new set of 84 broad absorption line (BAL) quasars (1.7 < zem < 4.4) exhibiting an appearance of C IV BAL troughs over 0.3–4.8 rest-frame years by comparing the Sloan Digital Sky Survey Data Release (SDSSDR)-7, ...
  • Galaxy flybys: evolution of the bulge, disc, and spiral arms 
    Ankit Kumar; Mousumi Das; Kataria, Sandeep Kumar (Oxford University Press on behalf of the Royal Astronomical Society, 2021-09)
    Galaxy flybys are as common as mergers in low-redshift Universe and are important for galaxy evolution as they involve the exchange of significant amounts of mass and energy. In this study, we investigate the effect of ...
  • Evolution of primordial dark matter planets in the early Universe 
    Kiren, O. V; Arun, K; Sivarani, C (Elsevier B. V, 2021-08-15)
    In a recent paper we had discussed possibility of DM at high redshifts forming primordial planets composed entirely of DM to be oneof the reasons for not detecting DM (as the flux of ambient DM particles would be consequently ...
  • In-orbit performance of UVIT over the past 5 years 
    Ghosh, S. K; Joseph, P; Kumar, A; Postma, J; Stalin, C. S; Subramaniam, A; Tandon, S. N; Barve, Indrajit V; Devaraj, A; George, K; Girish, V; Hutchings, J. B; Kamath, P. U; Kathiravan, S; Lancelot, J. P; Leahy, D; Mahesh, P. K; Mohan, R; Nagabhushana, S; Pati, A. K; Kameswara Rao, N; Sankarasubramanian, K; Sreekumar, P; Sriram, S (Indian Academy of Sciences, 2021-10)
    Over the last 5 years, UVIT has completed observations of more than 500 proposals with ∼800 unique pointings. In addition, regular planned monitoring observations have been made and from their analysis various key parameters ...
  • Is the binding energy of galaxies related to their core black hole mass? 
    Sivaram, C; Arun, K (Indian Academy of Sciences, 2021-10)
    Most of the large galaxies host a supermassive black hole, but their origin is still not well understood. In this paper, we look at a possible connection between the gravitational binding energies of large galaxies, etc., ...
  • Multiband transit follow-up observations of five hot Jupiters with critical noise treatments: improved physical properties 
    Saha, Suman; Chakrabarty, Aritra; Sengupta, S (IOP Publishing, 2021-07-01)
    The most challenging limitation in transit photometry arises from the noises in the photometric signal. In particular, the ground-based telescopes are heavily affected by the noise due to perturbation in the Earth’s ...
  • Stellar substructures in the periphery of the Magellanic Clouds with the VISTA hemisphere survey from the red clump and other tracers 
    El Youssouf, Dalal; Cioni, Maria-Rosa L; Bell, C. P. M; de Grijs, Richard; Groenewegen, M. A. T; Ivanov, Valentin D; Matijevic, Gal; Niederhofer, Florian; Oliveira, Joana M; Ripepi, Vincenzo; Schmidt, Thomas; Subramanian, S; Sun, Ning-Chen; van Loon, Jacco Th (Oxford University Press on behalf of the Royal Astronomical Society, 2021-08)
    We study the morphology of the stellar periphery of the Magellanic Clouds in search of substructure using near-infrared imaging data from the Visible and Infrared Survey Telescope for Astronomy Hemisphere Survey. Based on ...
  • Non-sinusoidal transit timing variations for the exoplanet HAT-P-12b 
    Sariya, Devesh P; Jiang, I.- G; Su, Li-Hsin; Yeh, Li-Chin; Chang, Tze-En; Moskvin, V. V; Shlyapnikov, A. A; Ignatov, V; Mkrtichian, David; Griv, Evgeny; Mannaday, Vineet Kumar; Thakur, Parijat; Sahu, D. K; Chand, Swadesh; Bisht, D; Sun, Zhao; Ji, Jianghui (IOP Publishing, 2021-04)
    Considering the importance of investigating the transit timing variations (TTVs) of transiting exoplanets, we present a follow-up study of HAT-P-12b. We include six new light curves observed between 2011 and 2015 from three ...
  • Multiwavelength monitoring of NGC 1275 over a decade: evidence of a shift in synchrotron peak frequency and long-term multiband flux increase 
    Gulati, Sanna; Bhattacharya, Debbijoy; Bhattacharyya, Subir; Bhatt, N; Stalin, C. S; Agrawal, V. K (Oxford University Press on behalf of the Royal Astronomical Society, 2021-05)
    We carried out a detailed study of the temporal and broad-band spectral behaviour of one of the brightest misaligned active galaxies in γ-rays, NGC 1275, utilizing 11 years of Fermi data and the available Swift and AstroSat ...
  • UOCS – III. UVIT catalogue of open clusters with machine learning-based membership using Gaia EDR3 astrometry 
    Jadhav, Vikrant K; Pennock, C. M; Subramaniam, A; Sagar, R; Prasanta Kumar Nayak (Oxford University Press on behalf of the Royal Astronomical Society, 2021-05)
    We present a study of six open clusters (Berkeley 67, King 2, NGC 2420, NGC 2477, NGC 2682, and NGC 6940), using the Ultra Violet Imaging Telescope (UVIT) aboard ASTROSAT and Gaia EDR3. We used combinations of astrometric, ...
  • Prospects of constraining reionization model parameters using Minkowski tensors and Betti numbers 
    Akanksha, K; Pravabati, C; Ghara, Raghunath; Appleby, Stephen; Choudhury, T. R (IOP Publishing, 2021-05)
    We explore the possibility of constraining model parameters of the Epoch of Reionization (EoR) from 21cm brightness temperature maps, using a combination of morphological descriptors constructed from the eigenvalues of ...
  • Tracking the evolution of Lithium in giants using asteroseismology: super-Li-rich stars are almost exclusively young red-clump stars 
    Raghubar Singh; Reddy, B. E; Campbell, S. W; Bharat Kumar, Y; Vrard, Mathieu (IOP Publishing, 2021-05-20)
    We report novel observational evidence on the evolutionary status of lithium-rich giant stars by combining asteroseismic and lithium abundance data. Comparing observations and models of the asteroseismic gravity-mode period ...
  • Chemical Analysis of Two Extremely Metal-poor Stars HE 2148-2039 and HE 2155-2043 
    Meenakshi, P; Goswami, A (IOP Publishing, 2021-05-01)
    We present elemental abundance results for HE 2148−2039 and HE 2155−2043 based on a detailed high-resolution spectroscopic analysis. The high-resolution Subaru/High Dispersion Spectrograph (HDS) spectra used for our analysis ...
  • Spectroscopic study of CEMP-(s & r/s) stars: Revisiting classification criteria and formation scenarios, highlighting i-process nucleosynthesis 
    Goswami, P. P; Rathour, R. S; Goswami, A (EDP Sciences, 2021-05)
    Context. The origin of the enhanced abundances of both s- and r-process elements observed in a subclass of carbon-enhanced metal-poor (CEMP) stars, denoted CEMP-r/s stars, still remains poorly understood. The i-process ...
  • A geometric method to locate Neptune 
    Bhatnagar, S; Vyasanakere, J. P; Murthy, J (American Association of Physics Teachers, 2021-05)
    We develop a direct geometric method to determine the orbital parameters and mass of a planet, and we then apply the method to Neptune using high-precision data for the other planets in the solar system. The method is ...
  • Planetary nebulae with UVIT: A progress report 
    Kameswara Rao, N; Sutaria, F; Murthy, J; Ray, A; Pandey, G (Indian Academy of Sciences, 2021-10)
    The spectral region between 1250–3000 A contains important spectral lines to understand the ˚ morphological structures and evolution of planetary nebulae. This is the region sampled by UVIT through various filter bands ...
  • The central region of the enigmatic Malin 1 
    Saha, Kanak; Dhiwar, Suraj; Barway, Sudhanshu; Narayan, Chaitra; Tandon, Shyam (Indian Academy of Sciences, 2021-10)
    Malin 1, being a class of giant low surface galaxies, continues to surprise us even today. The HST/F814W observation has shown that the central region of Malin 1 is more like a normal SB0/a galaxy, while the rest of the ...
  • UVIT observation of Milky Way satellite galaxy Reticulum II 
    Divakar, D. K; Sivarani, T; Doddamani, V. H (Indian Academy of Sciences, 2021-10)
    We present the UV photometry of one of the Ultra-Faint Dwarf (UFD) Milky Way (MW) satellite galaxies, Reticulum II, using images acquired with the Ultra-Violet Imaging Telescope (UVIT) onboard AstroSat. Reticulum II is ...

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