Publications of Astronomical Society of India: Recent submissions

  • Lunar Occulations with Infrared Arrays 
    Chandrasekhar, T; Shah, R; Mondal, S (Astronomical Society of India, 2003)
    Recently we have successfully observed the lunar occulation of a carbon star IRC+20120 and a M5 star IRC+10241 with the NICMOS sub array at the 1.2m Gurushikhar telescope. The integration times were respectively 5 millisec ...
  • Infrared L'band (lambda-cen- ~3.9 mu-m) observations with TIFR near-infrared camera (TIRCAM). 
    Ojha, D. K; Ghosh, S. K; Verma, R. P; Anandarao, B. G (Astronomical Society of India, 2003)
    TIRCAM is based on the SBRC InSb Focal Plane Array (58 x 62 pixels) sensitive between 1- 5 μm. TIRCAM system is described in Ojha et al. (2002). TIRCAM had its first light observations during March-April 2001 from Gurusikhar ...
  • Near Infrared PICNIC Imager (NIPI) - A Progress Report 
    Deep, A; Ramaprakash, A. N; Tandon, S. N; Gupta, R; Burse, M. P; Chordia, P. A; Das, H. K; Engineer, S; Kohok, A. A; Mestry, V. B (Astronomical Society of India, 2003)
    In the ASI 2002 meeting we presented a preliminary design of Near Infrared PICNIC Imager (Deep et al, 2002). In this paper we will show the progress that has been made since then.
  • On the Resolving Power of an Echelle Grating in the Presence of a Corrugated Wavefront of Incidence 
    Chatterjee, S; Banyal, R. K; Prasad, B. R; Chandrasekharan, K (Astronomical Society of India, 2003)
  • Model of planetary motion in the works of Kerala astronomers 
    Ramasubramanian, K (Astronomical Society of India, 1998)
    In this report, we discuss the significant advances in planetary theory made by the Kerala astronomers during 14th to 18th centuries. A geometrical picture of planetary motion, where the five planets Mercury, Venus, Mars, ...
  • An Extended Matched Filtering Method to Detect Periodicities in a Rough Grating for Extremely Large Roughness 
    Vani, V. C; Chatterjee, S (Astronomical Society of India, 2003)
    Matched filtering algorithm has beenshown by us to be an effective method to detect hidden periodicities in a rough grating, extending detectability to regimes of higher roughness than was hitherto known. The above matched ...
  • Performance Evaluation of Adaptive Optics Systems 
    Sridharan, R; Raja Bayanna, A; Srivastava, N; Kumar, B; Ravindra, B; Gupta, S. K; Jain, N; Ambastha, A; Venkatakrishnan, P (Astronomical Society of India, 2003)
    Adaptive Optics (AO) systems improve the resolution of ground based telescopes and allow for long exposure images. Their performance depends on the seeing conditions at the time of observations. In this paper, we evaluate ...
  • Night Sky Extinction Measurements at the Indian Astronomical Observatory, Hanle 
    Parihar, P. S; Sahu, D. K; Bhatt, B. C; Subramaniam, A; Anupama, G. C; Prabhu, T. P (Astronomical Society of India, 2003)
    We present the estimates of the night sky extinction at the Indian Astronomical Observatory. Also presented are the estimates of the night sky brightness. The extinction in the U band at IAO is found to be lower than the ...
  • The pancasiddhantika of Varahamihira : A puzzling problem is its presently available text 
    Sarma, K. V (Astronomical Society of India, 1998)
    It is pointed out that Pancasiddhantika of Varahamihira lacks lacks the sequential and logical arrangement of topics as found in his other works like Brhajjataka. It is concluded that the presently available version might ...
  • Search for HI Reionization Epoch in the Early Universe 
    Swarup, G (Astronomical Society of India, 2003)
    One of the most challenging problems in astronomy today is to search for reionization of the neutral hydrogen (HI), which is expected to occur somewhere between redshifts of about 6 to 20. The reionization is likely to ...
  • Dissipative Collapse of a Spherical Cluster of Gas Clouds 
    Indulekha, K; Vijayagovindan, G. V; Ramadurai, S (Astronomical Society of India, 2003)
    We investigate the time scale for the dissipative collapse of a spherical cluster of gas clouds by supplementing the scalar virial equation with an evolution equation for the energy. We find that collapse times are more ...
  • A Statistical Study of 3EG Source Characteristics 
    Sharma, M; Kaul, R. K (Astronomical Society of India, 2003)
    A detailed statistical study of 3EG source characteristics and their variation as a function of galactic latitude shows that a majority of Unidentified sources at mid galactic latutudes are so-far undetected AGN.
  • Polarization Asymmetry in CSS Sources 
    Saikia, D. J; Gupta, N (Astronomical Society of India, 2003)
    We show that the compact steep spectrum sources are more asymmetric in the polarization of the outer lobes compared with the more extended ones. This could be due to interaction of the jets with infalling material, which ...
  • An Expanding Plasma Model for the X-ray/radio knots in KPC-scale Jets of Active Galactic Nuclei 
    Sahayanathan, S; Misra, R; Kembhavi, A. K; Kaul, C. L (Astronomical Society of India, 2003)
    We model the observed X-ray/radio knots in Active Galactic Nuclei (AGN) as isotropically expanding spherical plasma clouds fed continously by non-thermal electrons. The time-dependent electron distribution and the emitted ...
  • Spectroscopic survey of field stars : A search for metal-poor stars 
    Giridhar, S; Goswami, A (Astronomical Society of India, 2002)
    We have undertaken a spectroscopic survey of field stars to fine metal-poor objects among them. Though the main objective of the survey is to find new metal-poor stars, stellar parameterization is carried out for all the ...
  • A Study of Giant Radio Galaxies 
    Konar, C; Saikia, D. J; Ishwara-Chandra, C. H; Kulkarni, V. K (Astronomical Society of India, 2003)
    Multi-frequency radio observations have been made of a sample of 17 giant radio galaxies, many of whose structures were not well determined earlier. These sources were observed with the VLA D- and B/C arrays at C and L ...
  • Magnetic Field Geometry of 3C111 on pc-scales 
    Kharb, P; Gabuzda, D; Shastri, P (Astronomical Society of India, 2003)
    Multi-epoch Very Long Baseline Polarimetric observations of the Broad Line Radio galaxy 3C111 performed at 8 and 43 GHz after a large millimetre outburst, reveal rapidly evolving parsec-scale radioo structure and the ...
  • IR observations of Am stars 
    Shylaja, B. S; Ashok, N. M (Astronomical Society of India, 2002)
    The IR observations of chemically peculiar stars are carried out and compared with the previous data in IR and far IR from IRAS. The flux redistribution appears to be a common phenomenon in all the stars of this class. The ...
  • Spectroscopy of Seyferts in the Far-UV 
    Shastri, P; Murthy, J; Hutchings, J (Astronomical Society of India, 2003)
    We present our preliminary far-ultraviolet spectra of the Seyfert Mrk 533 obtained with FUSE. These are among the first FUV spectra of a purportedly edge-on Seyfert, and show narrow OVI emission as well as some evidence ...
  • Low Frequency Observations of a Head-Tail Radio Source 
    Vir Lal, D; Pramesh Rao, A (Astronomical Society of India, 2003)
    We have mapped the head-tail radio galaxy, 3C 129 at 240 and 610 MHz using the GMRT and studied the detailed morphology and spectral index variations in this object. This is the first attempt to observe a sample of head-tail ...

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