IIA Institutional Repository: Recent submissions

  • Characterizing the companion AGBs using surface chemical composition of barium stars 
    Shejeelammal, J; Goswami, A; Goswami, P. P; Rathour, R. S; Masseron, T (Oxford University Press on behalf of the Royal Astronomical Society, 2020-10)
    Barium stars are one of the important probes to understand the o rigin and evolution of slow neutron-capture process elements in the Galaxy. These are e xtrinsic stars, where the observed s-process element abundances ...
  • VHE gamma-ray observation of Crab Nebula with HAGAR telescope array 
    Singh, B. B; Britto, R. J; Chitnis, V. R; Shukla, A; Saha, L; Sinha, A; Acharya, B. S; Vishwanath, P. R; Anupama, G. C; Bhattacharjee, P; Gothe, K .S; Nagesh, B. K; Prabhu, T. P; Rao, S. K; Srinivasan, R; Upadhya, S. S (Springer, 2019-12)
    HAGAR is a system of seven Non-imaging Atmospheric Cherenkov Telescopes located at Hanle in the Ladakh region of the Indian Himalay as at an altitude of 4270 meters amsl . Since 2008, we have observed the Crab Nebula to ...
  • On observations of the Great Comet of 1807 (C/1807 R1) from India 
    Kapoor, R. C (National Astronomical Research Institute of Thailand, 2019-04)
    Captain John Warren, the Acting Astronomer at Madras Observatory between 1805 and 1811, observed the Great Comet of 1807 (now C/1807 R1) and computed its orbit. He wrote up his observations in a paper titled ―An account ...
  • John Warren's unpublished observations of the Great Comet of 1811 from India 
    Kapoor, R. C (National Astronomical Research Institute of Thailand, 2019-04)
    Captain John Warren was the Acting Astronomer of Madras Observatory during the years 1805‒1811 when the Astronomer John Goldingham went to England on leave. At Madras, Warren observed the Great Comet of 1807 (C/1807 R1), ...
  • On two seventeenth century Persian paintings depicting comets or fireballs 
    Kapoor, R. C (National Astronomical Research Institute of Thailand, 2019-08)
    In the Theodore M. Davis Collection of the Metropolitan Museum of Art in New York there are two seventeenth century Persian paintings by Muhammad Zaman and Ali Quli Jubbahdar that depict comets or fireballs. From the ...
  • High-resolution Infrared Spectrograph for Exoplanet Characterization with the Keck and Thirty Meter Telescopes 
    Mawet, Dimitri; Fitzgerald, Michael; Konopacky, Quinn; Beichman, Charles; Jovanovic, Nemanja; Dekany, Richard; Hover, David; Chisholm, Eric; Ciardi, David; Artigau, Etienne; Banyal, Ravinder; Beatty, Thomas; Benneke, Bjorn; Blake, Geoffrey A; Burgasser, Adam; Canalizo, Gabriela; Chen, Guo; Do, Tuan; Doppmann, Greg; Doyon, Rene; Dressing, Courtney; Fang, Min; Greene, Thomas; Hillenbrand, Lynne; Howard, Andrew; Kane, Stephen; Kataria, Tiffany; Kempton, Eliza; Knutson, Heather; Kotani, Takayuki; Lafreniere, David; Liu, Chao; Nishiyama, Shogo; Pandey, G; Plavchan, Peter; Prato, Lisa; Rajaguru, S. P; Robertson, Paul; Salyk, Colette; Sato, Bun’ei; Schlawin, Everett; Sengupta, S; Sivarani, T; Skidmore, Warren; Tamura, Motohide; Terada, Hiroshi; Vasisht, Gautam; Wang, Ji; Zhang, Hui (American Astronomical Society, 2019-09)
    HISPEC (High-resolution Infrared Spectrograph for Exoplanet Characterization) is a proposed diffractionlimited spectrograph for the W.M. Keck Observatory, and a pathfinder for the MODHIS facility project (Multi-Object ...
  • Automated detection of solar radio bursts using a statistical method 
    Singh, D; Raja, K. S; Subramanian, P; Ramesh, R; Monstein, Christian (Springer, 2019-11)
    Radio bursts from the solar corona can provide clues to forecast space-weather hazards. After recent technology advancements, regular monitoring of radio bursts has increased and large observational datasets are produced. ...
  • Decaying turbulence and magnetic fields in galaxy clusters 
    Sur, Sharanya (Oxford University Press on behalf of the Royal Astronomical Society, 2019-12)
    We explore the decay of turbulence and magnetic fields generated by fluctuation dynamo action in the context of galaxy clusters where such a decaying phase can occur in the aftermath of a major merger event. ...
  • Periodic and Quasi-Periodic Variations in the Ca K Index During the 20th Century Using Kodaikanal Data 
    Priyal, Muthu; Singh, J; Ravindra, B; Chandar Shekar, B (Springer, 2019-09)
    We have digitized the Ca K images obtained at Kodaikanal Observatory with a pixel resolution of 0.86 arcsec and 16-bit readout to achieve better spatial and photometric accuracy. In addition to the general photometric ...
  • Observational studies of hydrogen-deficient stars for investigating their evolutionary connections 
    Hema, B. P (Indian Institute of Astrophysics, 2014-04)
    The group of hydrogen-deficient (H-deficient) and carbon rich supergiants spanning a range in their effective temperatures are: hydrogen deficient carbon (HdC) stars, R Coronae Borealis (RCB) stars, and extreme helium ...
  • Decaying turbulence and magnetic fields in galaxy clusters 
    Sur, Sharanya (Oxford University Press on behalf of the Royal Astronomical Society, 2019-09)
    We explore the decay of turbulence and magnetic fields generated by fluctuation dynamo action in the context of galaxy clusters where such a decaying phase can occur in the aftermath of a major merger event. Using idealized ...
  • Automated Detection of Solar Radio Bursts Using a Statistical Method 
    Singh, Dayal; Sasikumar Raja, K; Subramanian, Prasad; Ramesh, R; Monstein, Christian (Springer, 2019-08)
    adio bursts from the solar corona can provide clues to forecast space-weather hazards. After recent technology advancements, regular monitoring of radio bursts has increased and large observational datasets are produced. ...
  • Multiband optical variability of 3C 279 on diverse time scales 
    Aditi Agarwal; Cellone, Sergio A; Andruchow, I; Mammana, Luis; Singh, Mridweeka; Anupama, G. C; Mihov, B; Raj, A; eva-Mihova, L; Ozdonmez, Aykut; Ege, Ergun (Oxford University Press on behalf of the Royal Astronomical Society, 2019-09)
    We have monitored the flat spectrum radio quasar, 3C 279, in the optical B, V, R, and I passbands from 2018 February to 2018 July for 24 nights, with a total of 716 frames, to study flux, colour, and spectral variability ...
  • Are narrow-line seyfert 1 galaxies powered by low-mass black holes? 
    Viswanath, G; Stalin, C. S; Rakshit, S; Kurian, K. S; Ujjwal, K.; Gudennavar, S. B; Kartha, S. S (IOP Publishing, 2020-03)
    Are Narrow-line Seyfert 1 Galaxies Powered by Low-mass Black Holes? Gayathri Viswanath 1 , C. S. Stalin 2 , Suvendu Rakshit 3 , Kshama S. Kurian 2 , K. Ujjwal 1 , Shivappa B. Gudennavar 1 , and Sreeja S. ...
  • Binarity among objects with the Be and B[e] phenomena 
    Miroshnichenko, A. S; Zharikov, S.V; Korcakova, D; Manset, N; Mennickent, R; Khokhlov, S. A; Danford, S; Raj, A; Zakhozhay, O.V (Astronomical Institute of the Slovak Academy of Sciences, 2020-03)
    Many B-type stars exhibit two phenomena that are symbolized Be and B[e]. The former refers to presence of a circumstellar gaseous disk without significant circumstellar dust, while the latter have dust. Although neither ...
  • Hα full line spectropolarimetry as diagnostics of chromospheric magnetic field 
    Nagaraju, K; Sankarasubramanian, K; Rangarajan, K. E (Indian Academy of Sciences, 2020-12)
    Analysis of spectropolarimetric observations of two circular sunspots located close to disk centre in Hα (6562.8 Å) and Fe i (6569.22 Å) is presented in this paper. The corresponding active region numbers areNOAA 10940 and ...
  • MOND, MONG, MORG as alternatives to dark matter and dark energy, and consequences for cosmic structures 
    Sivaram, C; Arun, Kenath; Rebecca, Louise (Indian Academy of Sciences, 2020-02)
    In view of the negative results from various dark matter detection experiments, we propose alternate models by postulating a minimal field strength (minimal curvature) and also a minimal acceleration. These postulates ...
  • High-Frequency Dynamics of Active Region Moss as Observed by IRIS 
    Narang, Nancy; Pant, V; Banerjee, D; Doorsselaere, Tom Van (Frontiers, 2019-05-16)
    The high temporal, spatial and spectral resolution of Interface Region Imaging Spectrograph (IRIS) has provided new insights into the understanding of different small-scale processes occurring at the chromospheric and ...
  • From the margins to the mainstream: Nobel celebrates exoplanets! 
    Puravankara, Manoj; Banyal, R. K; Narang, Mayank (Indian Physics Association, 2019-12)
    This year’s Physics Nobel Prize was jointly awarded to three scientists. Phillip James Peebles from Princeton University, USA, received one half of the prize for his seminal work on physical cosmology, and other half was ...
  • Distance, Luminosity and evolutionary status of epsilon Aurigae (F0Iaep) from Gaia DR2 parallax 
    Parthasarathy, M; Muneer, S (Konkoly Observatory, 2019-01)
    From Gaia DR2 parallax of ǫ Aurigae the distance, Mv, Mbol, and log(L∗/L⊙sun) are found to be 445 parsecs, −6.5 mag, −6.5 mag, and 4.5 respectively. These results clearly indicate that ǫ Aurigae (F0Iae) is post-AGB star. ...

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