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Browsing by Author "Girish, V"

Browsing by Author "Girish, V"

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  • Characterization of the HD 219134 multi-planet system I. Observations of stellar magnetism, wind, and high-energy flux 
    Folsom, C. P; Fossati, L; Wood, B. E; Sreejith, A. G; Cubillos, P. E; Vidotto, A. A; Alecian, E; Girish, V; Lichtenegger, H; Murthy, J; Petit, P; Valyavin, G (Oxford University Press on behalf of the Royal Astronomical Society, 2018-12)
    HD 219134 hosts several planets, with seven candidates reported, and the two shortest period planets are rocky (4–5 M⊕) and transit the star. Here, we present contemporaneous multiwavelength observations of the star ...
  • Discovery of pulsations in HD 98851 
    Joshi, S; Girish, V; Martinez, P; Sagar, R; Ashoka, B. N; Gupta, S. K; Seetha, S; Chaubey, U. S; Kurtz, D. W (Astronomical Society of India, 2001)
    Using the UPSO 1-m Sampurnanand reflector telescope equipped with a fast photometer, we observed the chemically peculiar (CP) star HD 98851 for a total of around 30 hours on 5 different nights between January to April 2000. ...
  • HD 12098 a new far-northern roAp star 
    Girish, V; Joshi, S; Seetha, S; Ashoka, B. N; Martinez, P; Chaubey, U. S; Gupta, S. K; Kurtz, D. W; Sagar, R (Astronomical Society of India, 2001)
    The rapidly oscillating Ap (roAp) stars are cool, magnetic, chemically peculiar stars which pulsate in non-radial p-modes in the period range 4-16 min and have Johnson B amplitudes less than 8 mmag. "The NainiTal-Cape ...
  • 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 ...
  • 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 ...
  • 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 ...
  • Mapping distortion of detectors in UVIT onboard astroSat observatory 
    Girish, V; Tandon, S. N; Sriram, S; Amit Kumar; Postma, J (Springer, 2017-02)
    Ultraviolet Imaging Telescope (UVIT) is one of the payloads onboard AstroSat, India’s first multi-wavelength Astronomy mission. UVIT is primarily designed to make high resolution images in wide field, in three wavelength ...
  • Naini Tal-Cape survey for pulsating chemically peculiar stars - A status report 
    Seetha, S; Chaubey, U. S; Girish, V; Joshi, S; Ashoka, B. N; Gupta, S. K; Kurtz, D. W; Martinez, P; Sagar, R (Astronomical Society of India, 2001)
    The "Naini Tal-Cape survey for rapidly oscillating Ap stars", to search the northern hemi-sphere sky for pulsating stars was initiated in 1997. This is a collaboration between India and South Africa. So far about 70 stars ...
  • New pulsating variables discovered from the Naini Tal-Cape survey 
    Seetha, S; Ashoka, B. N; Joshi, S; Girish, V; Sagar, R; Chaubey, U. S; Gupta, S. K (Astronomical Society of India, 2002-09)
    The Naini Tal-Cape survey has been initiated to search for pulsations in chemically peculiar A and F type stars. Many of the magnetic A peculiar type stars exhibit rapid oscillations with periods ranging from 4-16 minutes. ...
  • Noise modeling and analysis of an IMU-based attitude sensor: improvement of performance by filtering and sensor fusion 
    Subramaniam, A; Sindhu, N; Tandon, S. N; Kameswara Rao, N; Postma, J; Cote, Patrick; Hutchings, J. B; Ghosh, S. K; George, K; Girish, V; Mohan, Rekhesh; Murthy, J; Sankarasubramanian, K; Stalin, C. S; Sutaria, F. K; Mondal, Chayan; Snehalata Sahu (SPIE-The International Society for Optical Engineering, 2016-07)
    We describe the characterization and removal of noises present in the Inertial Measurement Unit (IMU) MPU- 6050, which was initially used in an attitude sensor, and later used in the development of a pointing system for ...
  • UPSO three channel fast photometer 
    Gupta, S. K; Sagar, R; Joshi, S; Ashoka, B. N; Babu, V. C; Seetha, S; Girish, V (Astronomical Society of India, 2001)
    The design and performance of a modular portable three channel fast photometer is described. It can be disassembled as single individual channels such that the system can also be used as a single channel photometer. The ...
  • X - ray spectrometers on - board Aditya - L1 for solar flare studies 
    Sankarasubramanian, K; Sudhakar, M||Nandi, Anuj; Ramadevi, M. C; Adoni, A. A; Kushwaha, A; Agarwal, Anil; Dey, A; Joshi, B; Singh, Brajpal; Girish, V; Tomar, I; Majhi, K. K; Kumar; Olekar, Manjunath; Bug, M; Pala, Manohar; Thakur, Mukund Kumar; Badagandi, Rajeev R; Ravishankar, B. T; Garg, Sarthak|; Sitaramamurthy, N; Sridhara, N; Umapathy, C. N; Gupta, Vinod Kumar; Agrawal, Vivek Kumar; Yougandar, B (Current Science Association, 2017-08)
    Aditya-L1 mission will carry two high-spectral resolution X-ray spectrometers to study solar flares. The soft X-ray spectrometer will cover the energy range from 1 to 30 keV, while the hard X-ray spectrometer will cover ...

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