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Browsing by Author "Subramaniam, A"

Browsing by Author "Subramaniam, A"

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  • Field blue straggler stars: discovery of white dwarf companions to blue metal-poor stars using UVIT/AstroSat 
    Panthi, Anju; Subramaniam, A; Vaidya, Kaushar; Jadhav, Vikrant V; Sharmila Rani; Sivarani, T; Pandey, Sindhu (Oxford University Press on behalf of Royal Astronomical Society, 2023-10)
    Blue metal-poor (BMP) stars are the main-sequence stars that appear bluer and more luminous than normal turn-off stars of metal-poor globular clusters. They are believed to be either field blue straggler stars (FBSS) formed ...
  • The First Extensive Exploration of UV-bright Stars in the Globular Cluster NGC 2808 
    Deepthi, S. Prabhu; Subramaniam, A; Snehalata Sahu (IOP Publishing, 2021-02-10)
    In this study, we identified and characterized the hot and luminous UV-bright stars in the globular cluster NGC 2808. We combined data from the Ultra Violet Imaging Telescope (UVIT) on board the Indian space satellite AstroSat ...
  • First Results from the NOAO Survey of the Outer Limits of the Magellanic Clouds 
    Saha, A; Olszewski, E. W; Brondel, B; Olsen, K; Knezek, P; Harris, J; Smith, C; Subramaniam, A; Claver, J; Rest, A; Seitzer, P; Cook, K. H; Minniti, D; Suntzeff, N. B (IOP Publishing, 2010-12)
    We describe the first results from the Outer Limits Survey, an NOAO survey designed to detect, map, and characterize the extended structure of the Large and Small Magellanic Clouds (LMC and SMC). The survey consists of ...
  • Fundamental parameters of six neglected old open clusters 
    Carraro, G; Subramaniam, A; Janes, K. A (Royal Astronomical Society, 2006-09)
    In this paper, we present the first BV I CCD photometry of six overlooked old open clusters (Berkeley 44, NGC 6827, Berkeley 52, Berkeley 56, Skiff 1 and Berkeley 5) and derive estimates of their fundamental parameters by ...
  • GASP XVIII: star formation quenching due to AGN feedback in the central region of a jellyfish galaxy 
    George, K; Poggianti, B. M; Bellhouse, C; Radovich, M; Fritz, J; Paladino, R; Bettoni, R D; Jaff, Y; Moretti, A; Gullieuszik, M; Vulcani, B; Fasano, G; Stalin, C. S; Subramaniam, A; Tandon, S. N (Oxford University Press on behalf of the Royal Astronomical Society, 2019-08)
    We report evidence for star formation quenching in the central 8.6 kpc region of the jellyfish galaxy JO201 that hosts an active galactic nucleus (AGN), while undergoing strong ram-pressure stripping. The ultraviolet imaging ...
  • Generation of a Near Infra-Red Guide Star Catalog for Thirty-Meter Telescope Observations 
    Subramanian, S; Subramaniam, A; Simard, L; Gillies, K; Ramaprakash, A. N; Anupama, G. C; Stalin, C. S; Ravindranath, S; Reddy, B. E (Indian Academy of Sciences, 2013-06)
    The requirements for the production of a near Infra-Red Guide Star Catalog (IRGSC) for Thirty Meter Telescope (TMT) observations are identified and presented. A methodology to compute the expected J band magnitude of stellar ...
  • Globular cluster systems in giant elliptical galaxies : a probe for the galaxy formation and evolution 
    Subramaniam, A; Sagar, R (Astronomical Society of India, 2000)
    Most of the globular clusters in the universe reside in gaint elliptical galaxies. The number of GCs present in them is about a few thousands. Due to their large distances (> 10 Mpc), it is impossible to observe their ...
  • Globular Cluster UVIT Legacy Survey (GlobULeS) – I. FUV–optical colour–magnitude diagrams for eight globular clusters 
    Sahu, Snehalata; Subramaniam, A; Singh, Gaurav; Yadav, Ramakant; Valcarce, Aldo R; Choudhury, Samyaday; Sharmila Rani; Deepthi, S. Prabhu; Chung, Chul; Cote, Patrick; Leigh, Nathan; Geller, Aaron M; Chatterjee, Sourav; Kameswara Rao, N; Bandyopadhyay, Avrajit; Shara, Michael; Dalessandro, Emanuele; Pandey, G; Postma, Joesph E; Hutchings, John; Simunovic, Mirko; Stetson, Peter B; Sivarani, T; Puzia, Thomas; Sohn, Young-Jong (Oxford University Press on behalf of the Royal Astronomical Society, 2022-07)
    We present the first results of eight globular clusters (GCs) from the AstroSat/UVIT Legacy Survey programme GlobULeS based on the observations carried out in two far-ultraviolet (FUV) filters (F148W and F169M). The ...
  • Globular Cluster UVIT Legacy Survey (GlobULeS) – II. Evolutionary status of hot stars in M3 and M13 
    Kumar, Ranjan; Pradhan, Ananta C; Sahu, Snehalata; Subramaniam, A; Piridi, Sonika; Cassisi, Santi; Ojha, Devendra K (Oxford University Press on behalf of Royal Astronomical Society, 2023-06)
    We present a far-ultraviolet (FUV) study of hot stellar populations in the second parameter pair globular clusters (GCs) M3 and M13, as a part of the GC UVIT Legacy Survey programme (GlobULeS). We use observations made ...
  • Globular Cluster UVIT Legacy Survey (GlobULeS). III. Omega Centauri in Far-ultraviolet 
    Deepthi, S. Prabhu; Subramaniam, A; Sahu, Snehalata; Chung, Chul; Leigh, Nathan W. C; Dalessandro, Emanuele; Chatterjee, Sourav; Kameswara Rao, N; Shara, Michael; Cote, Patrick; Choudhury, Samyaday; Pandey, G; Valcarce, Aldo A. R; Singh, G; Postma, Joesph E; Sharmila Rani; Bandyopadhyay, Avrajit; Geller, Aaron M; Hutchings, John; Puzia, Thomas; Simunovic, Mirko; Sohn, Young-Jong; Sivarani, T; Yadav, Ramakant Singh (American Astronomical Society, 2022-11-10)
    We present the first comprehensive study of the most massive globular cluster, Omega Centauri, in the farultraviolet (FUV), extending from the center to ∼28% of the tidal radius using the Ultraviolet Imaging Telescope on ...
  • GlobULeS – V. UVIT/AstroSat studies of stellar populations in NGC 362: detection of blue lurkers in a globular cluster 
    Dattatrey, Arvind K; Yadav, R. K. S; Kumawat, Gourav; Sharmila Rani; Singh, Gaurav; Subramaniam, A; Singh, Ravi S (Oxford University Press on behalf of Royal Astronomical Society, 2023-07)
    We report the discovery of four blue lurkers with low- and extremely low mass white dwarf (ELM WD) companions in the Galactic globular cluster NGC 362 using AstroSat’s Ultra Violet Imaging Telescope (UVIT). We analysed ...
  • GlobULeS. IV. UVIT/AstroSat Detection of Extremely Low Mass White Dwarf Companions to Blue Straggler Stars in NGC 362 
    Dattatrey, Arvind K; Yadav, R. K. S; Sharmila Rani; Subramaniam, A; Singh, Gaurav; Sahu, Snehalata; Singh, Ravi S (American Astronomical Society, 2023-02-01)
    We report the discovery of extremely low mass white dwarfs (ELM WDs) as a companion of blue straggler stars (BSSs) in the Galactic globular cluster NGC 362 using images from AstroSatʼs Ultra Violet Imaging Telescope (UVIT). ...
  • High Mass-Ratio Binary Population in Open Clusters: Segregation of Early Type Binaries and an Increasing Binary Fraction with Mass 
    Jadhav, V. V; Roy, Kaustubh; Joshi, Naman; Subramaniam, A (IOP Publishing, 2021-12-01)
    Binary stars play a vital role in astrophysical research, as a good fraction of stars are in binaries. Binary fraction (BF) is known to change with stellar mass in the Galactic field, but such studies in clusters require ...
  • The horizontal branch morphology of the globular cluster NGC 1261 using AstroSat 
    Sharmila Rani; Pandey, G; Subramaniam, A; Sahu, S; Kameswara Rao, N (Indian Academy of Sciences, 2020-12)
    We present the results obtained from the UV photometry of the globular cluster NGC 1261 using far-UV (FUV) and near-UV (NUV) images acquired with the Ultraviolet Imaging Telescope (UVIT) on-board the AstroSat satellite. ...
  • The Horizontal Branch Population of NGC 1851 as Revealed by the Ultraviolet Imaging Telescope (UVIT) 
    Subramaniam, A; Snehalata Sahu; Postma, J; Cote, Patrick; Hutchings, J. B; Darukhanawalla, N; Chung, Chul; Tandon, S. N; Kameswara Rao, N; George, K; Ghosh, S. K; Girish, V; Murthy, J; Mohan, Rekhesh; Murthy, J; Pati, A. K; Sankarasubramanian, K; Stalin, C. S; Choudhury, S (IOP Publishing, 2017-12)
    The Horizontal Branch Population of NGC 1851 as Revealed by the Ultraviolet Imaging Telescope ( UVIT ) Annapurni Subramaniam 1 , Snehalata Sahu 1 , Joseph E. Postma 2 , Patrick Côté 3 , J. B. Hutchings 3 , ...
  • A hot companion to a blue straggler in NGC 188 as revealed by the ultra-violet imaging telescope (UVIT) on ASTROSAT 
    Subramaniam, A; Sindhu, N; Tandon, S. N; Kameswara Rao, N; Postma, J; Cote, Patrick; Hutchings, J. B; Ghosh, S. K; George, K; Girish, V (IOP Publishing, 2016-12-20)
    We present early results from the Ultra-Violet Imaging Telescope (UVIT) on board the ASTROSAT observatory. We report the discovery of a hot companion associated with one of the blue straggler stars (BSSs) in the old open ...
  • H I kinematics of the Large Magellanic Cloud revisited: Evidence of possible infall and outflow 
    Indu, G; Subramaniam, A (EDP Sciences, 2015-01)
    Aims. The neutral atomic Hydrogen (H I) kinematics of the Large Magellanic Cloud (LMC) is revisited in light of two new proper motion estimates. Methods. We analysed the intensity weighted H I velocity maps of the Australia ...
  • In-orbit Calibrations of the Ultraviolet Imaging Telescope 
    Tandon, S. N; Subramaniam, A; Girish, V; Postma, J; Sankarasubramanian, K; Sriram, S; Stalin, C. S; Mondal, Chayan; Sahu, S; Joseph, P; Hutchings, J; Ghosh, S. K; Barve, Indrajit V; George, K; Kamath, P. U; Kathiravan, S; Kumar, A; Lancelot, J. P; Leahy, D; Mahesh, P. K; Mohan, Rekhesh; Nagabhushana, S; Pati, A. K; Kameswara Rao, N; Sreedhar, Yuvraj Harsha; Sreekumar, P (IOP Publishing, 2017-09)
    The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT, the first Indian Space Observatory. The UVIT instrument has two 375 mm telescopes: one for the far-ultraviolet (FUV) channel (1300–1800 Å), ...
  • In-orbit performance of UVIT and first results 
    Tandon, S. N; Hutchings, J. B; Ghosh, S. K; Subramaniam, A; George, K|; Girish, V; Kamath, P. U; Kathiravan, S; Kumar, A; Lancelot, J.P; Mahesh, P. K; Mohan, Rekhesh; Murthy, J; Nagabhushana, S; Pati, A. K; Postma, J; Kameswara Rao, N; Sankarasubramanian, K; Sreekumar, P; Sriram, S; Stalin, C. S; Sutaria, F. K; Sreedhar, Yuvraj Harsha; Barve, Indrajit V; Mondal, Chayan; Snehalata Sahu (Indian Academy of Sciences, 2017-06)
    The performance of the ultraviolet telescope (UVIT) on-board AstroSat is reported. The performance in orbit is also compared with estimates made from the calibrations done on the ground. The sensitivity is found to be ...
  • In-orbit performance of UVIT on ASTROSAT 
    Subramaniam, A; Tandon, S. N; Hutchings, J; Ghosh, S. K; George, K; Girish, V; Kamath, P. U; Kathiravan, S; Kumar, Amit; Lancelot, J. P; Mahesh, P (SPIE--The International Society for Optical Engineering, 2016-07)
    We present the in-orbit performance and the first results from the ultra-violet Imaging telescope (UVIT) on ASTROSAT. UVIT consists of two identical 38cm coaligned telescopes, one for the FUV channel (130-180nm) and the ...

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