IIA Institutional Repository: Recent submissions

  • Present status of hard X-ray astronomy 
    Rao, A. R (Astronomical Society of India, 1993)
    The recent observational results obtained in the energy range of 15-150 keV from balloon and satellite borne instruments are reviewed. The detection of cyclotron line features in several X-ray binaries, hard X-ray spectra ...
  • X-ray structure of clusters of galaxies with ROSAT 
    Singh, K. P (Astronomical Society of India, 1993)
    X-ray emission from clusters of galaxies is due to thermal Bremsstrahlung from a hot thin gas in the intergalactic medium. The gas is generally considered to be smoothly distributed with a size of approximately 3 Mpc. X-ray ...
  • High resolution mapping in the far-infrared band 
    Rengarajan, T. N (Astronomical Society of India, 1993)
    The earth's atmosphere is opaque to the far-infrared (far-IR) radiation) and hence observations have to be carried out at altitudes above 12 km using telescopes transported by aircraft, balloon or satellite. The restriction ...
  • Imaging studies in the near infrared region 
    Anandarao, B. G (Astronomical Society of India, 1993)
    The advent of array detectors has given a tremendous boost to the detection capabilities in the near infrared region over the last 5 years. A variety of instrumentation has been and is being built around these panoramic ...
  • Stellar astronomy with VBT 
    Kameswara Rao, N (Astronomical Society of India, 1993)
    The 2.34 meter Vainu Bappu Telescope (VBT) has been operating as a national facility for the last 3-4 years. Some of the current observational programs with VBT regarding the galactic astronomy are reviewed
  • Spectroscopy of novae and supernovae 
    Prabhu, T. P (Astronomical Society of India, 1993)
    Many novae have been studied spectroscopically since 1975 and many supernovae since 1980 using the telescopes at Vainu Bappu Observatory (VBO). The program on novae has intensified since 1985, and that on supernovae has ...
  • Recent development in optical and IR polarimetry 
    Joshi, U. C (Astronomical Society of India, 1993)
    Polarimetry in recent years has matured and high precision measurements, from radio to UV wavelength, are possible in various modes: photo polarimetry, spectropolarimetry or imaging polarimetry. Within the country polarization ...
  • Starburst galaxies -- AGN connection: Theoretical scenario 
    Jog, Chanda J (Astronomical Society of India, 1993)
    Starburst galaxies are characterized by a very high central infrared luminosity of about 10/sup10/ - 10/sup12/ solar luminosity. This luminosity is attributed to a burst of formation of massive stars. The stellar radiation ...
  • Cosmic gamma ray bursts -- recent developments 
    Vahia, M. N (Astronomical Society of India, 1993)
    The Gamma Ray Bursts (GRB) have been observed for the last 20 years by a large number of satellites. However, till recently, comprehensive analysis was difficult in view of varying techniques used by different satellites. ...
  • A double-pass spectrograph for solar research 
    Kariyappa, R; Jayarajan, A. P; Raheem, K. C. A; Sivaraman, K. R (Astronomical Society of India, 1993-06)
    We have described the double-pass spectrograph built at the Indian Institute of Astrophysics. Measurements of the scattered light within the spectrograph using the photoelectric scans of the NaI D-lines show that this is ...
  • Isolated pairs of spiral galaxies--a statistical study of far infrared and microwave characteristics 
    Venugopal, V. R; Narasimhan, K. S. V. S (Astronomical Society of India, 1993-06)
    A statistical study of the far infrared and microwave (lambda 6.3 cm ) lumnosities of a sample of isolated pairs of spiral galaxies and a comparison sample on non-interacting galaxies selected from the lists given by ...
  • Mass extinction due to oscillation of Sun about the mid-galactic plane 
    Das, C; Rana, N. C (Astronomical Society of India, 1993-06)
    Apparent periodicity was observed in the mass extinction event for the past few hundred million years. Previous investigations suggested the observed period to be somewhat lower than the calculated period of oscillation ...
  • Halpha, microwave and hard X-ray observations of the two-ribbon flare of 1980 April 3 
    Jain, R (Astronomical Society of India, 1993-06)
    The Halpha observations of a class 2B two ribbon flare, associated with exceptional hard X-ray and microwave emissions, are presented and discussed. The observational relationship suggests that the gradient of the magnetic ...
  • On the electric circuit approach of coronal heating: a review 
    Narain, U; Kumar, S (Astronomical Society of India, 1993-06)
    It is now widely believed that the photosphere of the Sun and its outer atmosphere (chromosphere and corona) are electrodynamically coupled through interconnecting magnetic fields. A similar situation may exist in other ...
  • Astronomical orientations of the megalithic stone circles of Brahmagiri 
    Kameswara Rao, N (Astronomical Society of India, 1993-03)
    The megalithic stone circles at Brahmagiri which have been dated as 900 BC show clear astronomical orientations. The site lines from the center of a circle to an outer tangent of another circle points out to the directions ...
  • A note on the spectra of epsilon Aurigae 
    Subrahmanyam, P. V; Raghavender Rao, C; Sreedhar Rao, S (Astronomical Society of India, 1993-03)
    Spectroscopic observations of the long period variable epsilon Aurigae were made during its 1982-84 eclipse. It is found that the Ca II H and K lines show variation in their equivalent widths. The equivalent widths of these ...
  • Dwarf cepheid AD CMi -- revisited 
    Kilambi, G. C; Rahman, A (Astronomical Society of India, 1993-03)
    An analysis of UBVR light variations of AD Canis Minoris (CMi) is presented. The mean effective temperature derived from the intrinsic (B - V) index is estimated to be 7400 K +/- 100 K whereas that of the (V - R) index ...
  • CCD photometry of galactic open star clusters -- 2: NGC 7419 
    Bhatt, B. C; Pandey, A. K; Mohan, V; Mahra, H. S; Paliwal, D. C (Astronomical Society of India, 1993-03)
    CCD photometric observations of open cluster NGC 7419 in UBVRI passbands have been made down to V = 19.5 mag. Reddening across the cluster region is found to be variable. The mean visual absorption of 5.30 mag and a distance ...
  • Temperature and brightness distribution in the components of binary systems 
    Barman, S. K (Astronomical Society of India, 1993-03)
    From the theoretical model of a binary system for gravity darkening (Barman 1991), the temperature and brightness distributions along the surface of the components have been calculated using the third and fourth orders of ...
  • N-body problem 
    Bhatnagar, K. B; Saha, L. M (Astronomical Society of India, 1993-03)
    This is a review article on the N-body problem. The development of the qualitative methods regarding the various topics of Celestial Mechanics are presented in a systematic way starting from the early researches of the ...

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