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Browsing IIAP Publications by Title

Browsing IIAP Publications by Title

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  • Ultrahigh energy cosmic rays from topological defects-cosmic strings, monopoles, necklaces, and all that 
    Bhattacharjee, P (American Institute of Physics, 1998-06)
    The topological defect scenario of origin of the observed highest energy cosmic rays is reviewed. Under a variety of circumstances, topological defects formed in the early Universe can be sources of very massive particles ...
  • Ultraviolet astronomy with small space telescopes 
    Brosch, N; Gomez De Castro, Ana; Murthy, J; Ribak, E; Behar, E; Balabanov, V (Astronomical Institute of the Slovak Academy of Sciences, 2017-08)
    After describing the present situation with astronomy in the ultraviolet (UV), reviewing a few past and proposed future missions, we present options to develop space missions that have been realized for modest costs. In ...
  • The ultraviolet band systems of Bal molecule 
    Rao, M. L. P; Rao, D. V. K; Rao, P. T; Murthy, P. S (1977)
    The emission spectrum of the Bal molecule is excited in a R.F. discharge and photographed in the first order (reciprocal dispersion: 1.25 Å/mm) of a 21 ft. concave grating spectrograph. A comprehensive new vibrational ...
  • An ultraviolet imager to study bright UV sources 
    Mathew, J; Prakash, A; Mayuresh, Sarpotdar; Sreejith, A. G; Safonova, M; Murthy, J (SPIE-The International Society for Optical Engineering, 2016-07)
    We have designed and developed a compact ultraviolet imaging payload to y on a range of possible platforms such as high altitude balloon experiments, cubesats, space missions, etc. The primary science goals are to study ...
  • Ultraviolet imaging observations of three jellyfish galaxies: star formation suppression in the centre and ongoing star formation in stripped tails 
    George, K; Poggianti, B. M; Tomicic, N; Postma, J; Cote, P; Fritz, J; Ghosh, S. K; Gullieuszik, M; Hutchings, J. B; Moretti, A; Omizzolo, A; Radovich, M; Sreekumar, P; Subramaniam, A; Tandon, S. N; Vulcani, B (Oxford University Press on behalf of Royal Astronomical Society, 2023-02)
    Spiral galaxies undergo strong ram-pressure effects when they fall into the galaxy cluster potential. As a consequence, their gas is stripped to form extended tails within which star formation can happen, giving them the ...
  • Ultraviolet Imaging Telescope (UVIT) observation of the Galactic globular cluster NGC 7492 
    Kumar, R; Pradhan, A. C; Mohapatra, Abhisek; Moharana, Ayush; Ojha, D. K; Parthasarathy, M; Murthy, J (Oxford University Press on behalf of the Royal Astronomical Society, 2021-03)
    We present detailed photometric observations of the Galactic globular cluster NGC 7492 using the data obtained with two far-ultraviolet (FUV; 1300–1800 Å) and three near-ultraviolet (NUV; 2000–3000 Å) filters of Ultraviolet ...
  • Ultraviolet Imaging Telescope on AstroSat 
    Tandon, S. N; Ghosh, S. K; Hutchings, J; Stalin, C. S; Subramaniam, A (Current Science Association, 2017-08)
    The AstroSat satellite is designed for multiwavelength astronomy for observations covering a spectral range from soft and hard X-rays to the ultraviolet. The Ultraviolet Imaging Telescope (UVIT) is the only non-X-ray ...
  • Ultraviolet Imaging Telescope on AstroSat 
    Tandon, S. N; Ghosh, S. K; Hutchings, J; Stalin, C. S; Subramaniam, A (Current Science Association, 2017-04)
    Solar coronagraph mimics total solar eclipse by blocking the solar disk and enabling the observation of extended coronal atmosphere of the Sun. Visible Emission Line Coronagraph (VELC), on-board Aditya-L1 space mission, ...
  • Ultraviolet Imaging Telescope View of Dwarf Irregular Galaxy IC 2574: Is the Star Formation Triggered Due to Expanding H I Shells? 
    Chayan Mondal; Subramaniam, A; Koshy George (IOP Publishing, 2019-11)
    Star-forming dwarf galaxies in the local volume are diverse and ideal test beds to understand the details of star formation in a variety of environments. Here we present a deep far-UV ( FUV ) imaging study of the ...
  • Ultraviolet observations of the hydrogen-deficient variable star MV Sagittarii 
    Kameswara Rao, N; Nandy, K (Indian Academy of Sciences, 1982)
    IUE observations of the hydrogen-deficient irregular variable star MV Sgr obtained in June-October 1980 and November 1979 are discussed. The observations reveal a prominent 2200 A absorption feature. A value of E(B - V) = ...
  • The ultraviolet spectrum of the hydrogen-poor binary HD 30353 
    Parthasarathy, M; Hack, M; Tektunali, G (The European Southern Observatory, 1990-04)
    An analysis is made of the high- and low-resolution UV spectra of the hydrogen-poor star HD 30353. The stellar wind profiles of the resonance lines of N V, C V, and Si IV are found to be similar to those observed in Upsilon ...
  • Ultraviolet stellar population of the old open cluster M67 (NGC 2682) 
    Sindhu, N; Subramaniam, A; Anu Radha, C (Oxford University Press on behalf of the Royal Astronomical Society, 2018-11)
    We present the results of ultraviolet (UV) photometry of the old open cluster M67 obtained using Galaxy Evolution Explorer in far-ultraviolet (FUV) and near-ultraviolet (NUV) bands. UV detections of 18 blue straggler stars ...
  • Ultraviolet variability of HD 62001 - The central star of the missing nebula V-V 1-7 
    Kameswara Rao, N; Gilra, D. P (Indian Academy of Sciences, 1983-03)
    IUE observations of HD 62001 do not confirm the ultraviolet variability of 0.15 mag seen from the ANS observations. These intriguing variations in ANS observations seem to be caused by a nearby (∼ 70 arcsec away) B star ...
  • The ultraviolet variations of the post-AGB star HD 89353 
    Monier, R; Parthasarathy, M (The European Southern Observatory, 1999-01)
    Based on an analysis of all low resolution spectra of HD 89353 (HR 4049) obtained with the International Ultraviolet Explorer (IUE) over several years and uniformly reprocessed, we report on large ultraviolet variations ...
  • Uncertainty principle limits on the cosmological constant 
    Sivaram, C (Springer, 1986-08)
    The identification of the cosmological constant term with the energy density of the vacuum enables lower and upper limits to be placed on its value. The upper limit arises from the constraint that the total zero-point ...
  • Understanding AGB Nucleosynthesis from Chemical Composition Studies of CH Stars 
    Drisya, K; Goswami, A (Astronomical Society of the Pacific, 2015-08)
    CH stars are known to show enhanced abundances of carbon and heavy s-process elements. They are metal-deficient population II objects. Their luminosities indicate that they are mostly giants; hence, the observed enhanced ...
  • Understanding galaxy mergers and AGN feedback with UVIT 
    Rubinur, K; Mousumi Das; Kharb, Preeti; Rahne, P. T (Cambridge University Press, 2021-01)
    Simulations expect an enhanced star-formation and active galactic nuclei (AGN) activity during galaxy mergers, which can lead to formation of binary/dual AGN. AGN feedback can enhance or suppress star-formation. We have ...
  • Understanding ghost interference 
    Qureshi, T; Pravabati, C; Shafaq, S (World Scientific Publishing Company, 2016-09)
    The ghost interference observed for entangled photons is theoretically analyzed using wave-packet dynamics. It is shown that ghost interference is a combined effect of virtual double-slit creation due to entanglement, and ...
  • Understanding jets from sources straddling the Fanaroff-Riley divide 
    Kharb, P; Stanley, E; Lister, M; Marshall, H; O'Dea, C; Baum, S (Cambridge University Press, 2015-03)
    Results from Chandra-HST-VLA observations of 13 hybrid sources are presented. Data from ten sources in the literature are analysed along with new data from three hybrid blazars belonging to the MOJAVE sample. Studies of ...
  • Understanding Li enhancement in K giants and role of accurate parallaxes 
    Raghubar Singh; Reddy, B. E (Cambridge University Press, 2018-07)
    Our recent studies based on a large sample of K giants with Hipparcos parallaxes and spectroscopic analysis resulted more than a dozen new Li-rich K giants including few super Lirich ones. Most of the Li-rich K giants ...

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