• Central regions of Sérsic-Pastoriza galaxies: A photographic study

    • Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/joaa/001/02/0129-0154

    • Keywords

       

      galaxies—central regions—bursts of star formation—surface photometry

    • Abstract

       

      A classification scheme is proposed for the central regions of Sérsic-Pastoriza galaxies based on high resolution photographs of 50 objects in the integrated light (4000 Å-8700 Å). Structures of two different linear scales are recognized: (1) nucleus(≲1 kpc) and (2) perinuclear formation (∼l.5 kpc). The perinuclear formation is weak in classκ while the nucleus is too faint to detect in class ι. In the intermediate classesε andσ both the components are bright. Classε has an elliptical perinuclear formation with little gas while the classσ consists of bright H II complexes and dust. Observations of a few galaxies in the infrared and the blue ends of the image tube response show that the nucleus is generally redder than its surroundings. Equal intensity contours and the luminosity profiles are presented for the central regions of 27 galaxies. A comparison of their axial ratios with those of the parent galaxies indicates that the perinuclear formations are prolate or barlike. The dependence of the peak surface brightness of the central formation on the size of the bar is investigated as also the dependence of the central surface brightness of the bar on the size of the bar. The following major conclusions are drawn:

      1. The peak central surface brightness of the perinuclear formation varies as the square of the bar length. This relation implies that the bar induces the infall of gas from the bar-disk region.

      2. The formations of classσ move towards classε as star formation ceases and the massive stars die.

      3. The classι differs from classσ in the intensity of the burst of star formation. Low luminosity of the parent galaxies in classι implies less infall of gas and higher domination of the bar potential on the perinuclear formation. Thus the classι structures are more prolate than those of classσ.

      4. The central brightness of the bars varies directly as the length of the bar.

    • Author Affiliations

       

      T. P. Prabhu1

      1. Indian Institute of Astrophysics, Bangalore - 560034
    • Dates

       
  • 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

© 2017-2019 Indian Academy of Sciences, Bengaluru.