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Journal of Astrophysics and Astronomy

, Volume 23, Issue 1–2, pp 165–171 | Cite as

Tracking the shadows through GMRT

  • D. Narasimha
  • N. Kanekar
  • J. N. Chengalur
Article
  • 25 Downloads

Abstract

The structures of faint high redshift galaxies cannot be observed directly. But if a luminous quasar is located farther along their line of sight, high resolution absorption lines offer a valuable and reliable probe to their structure. GMRT is suited to monitor the absorption spectra, if the redshifted neutral hydrogen or OH doublet fall in one of the windows of the telescope. We present the OH doublet absorption spectra for the system B0218+357, taken at GMRT this year at resolution of approx. 9.5 km/sec with an rms noise of the order of 1 mJy. Based on our study of the OH doublet and 21cm neutral hydrogen line we infer that, in the lensing spiral galaxy of B0218 + 357, neutral hydrogen and OH coexist in tenous clouds and there is possibly a hole in the central part of the galaxy. In contrast, the gas is seen in high density clouds in the lens in an otherwise similar system PKS1830-211.

Key words

Gravitational lens, molecular absorption lines, quasar B0218 + 357 

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References

  1. Chengalur, J., de Bruyn, A. G., Narasimha, D. 1999,A&A,343, L79.ADSGoogle Scholar
  2. Patnaik, A. R.et al 1993,MNRAS,261, 435.ADSGoogle Scholar
  3. Wiklind, T., Combes, F. 1995,A&A,299, 382.ADSGoogle Scholar

Copyright information

© Indian Academy of Sciences 2002

Authors and Affiliations

  • D. Narasimha
    • 1
  • N. Kanekar
    • 2
  • J. N. Chengalur
    • 2
  1. 1.Tata Institute of Fundamental ResearchMumbai
  2. 2.Tata Institute of Fundamental ResearchNCRAPune

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