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    • Fulltext

       

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/joaa/002/04/0349-0363

    • Keywords

       

      stellar dynamics; galaxy collisions; tidal interaction

    • Abstract

       

      Head-on collisions of two identical spherical galaxies are studied for two initial velocities (1) nearly equal to and (2) greater than the capture velocity. Orbits of about 500 representative stars are computed taking into account the effects of dynamical friction in the motion of the galaxies. From the computer studies the changes in the structure of the galaxies are deduced. The galaxies contract at closest approach and expand as they recede from each other. When the initial velocity is nearly equal to the capture velocity, the mean radius expands to almost double its size and the galaxies have a prolate structure until the closest approach with the longer axis in the direction of motion. The prolate structure is destroyed as the galaxies recede. For larger collision velocity (V ∼ 1.5 Vcap), the mean radius expands by 50 per cent and the galaxies are prolate until the closest approach and distinctly oblate after the collision. The fractional increase in the binding energy is 0.46 in the first case and 0.30 in the second case.

    • Author Affiliations

       

      Farooq Ahmed1 2 3 Saleh Mohammed Alladin2

      1. Indian Institute of Astrophysics, Bangalore - 560034
      2. Centre of Advanced Study in Astronomy, Osmania University, Hyderabad - 500007
      3. Department of Physics, Kashmir University, Srinagar - 190006

    • Dates

       
      Published
      December 1981
      Manuscript received
      9 March 1981
      Accepted
      11 October 1981

  • Journal of Astrophysics and Astronomy | News

    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

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