2010 (IPP)

Permanent URI for this collectionhttp://localhost:4000/handle/11007/152

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Author: search.filters.author.Wadadekar, YogeshSubject: search.filters.subject.Galaxies

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    Quantitative measure of evolution of bright cluster galaxies at moderate redshifts
    (2010-01-01) Vikram, Vinu; et al.; Wadadekar, Yogesh; Kembhavi, A.K.
    Using archival data from the Hubble Space Telescope, we study the quantitative morphological evolution of spectroscopically confirmed bright galaxies in the core regions of nine clusters ranging in redshift from z = 0.31 to z = 0.84. We use morphological parameters derived from two dimensional bulge-disk decomposition to study the evolution. We find an increase in the mean bulge-to-total luminosity ratio B/T as the Universe evolves. We also find a corresponding increase in the fraction of early type galaxies and in the mean S´ersic index. We discuss these results and their implications to physical mechanisms for evolution of galaxy morphology.
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    PyMorph: Automated galaxy structural parameter rstimation using python
    (2010-07-20) Vikram, Vinu; et al.; Wadadekar, Yogesh; Kembhavi, A.K.
    We present a new software pipeline – PyMorph – for automated estimation of structural parameters of galaxies. Both parametric fits through a two dimensional bulge disk decomposition as well as structural parameter measurements like concentration, asymmetry etc. are supported. The pipeline is designed to be easy to use yet flexible; individual software modules can be replaced with ease. A find-and-fit mode is available so that all galaxies in a image can be measured with a simple command. A parallel version of the Pymorph pipeline runs on computer clusters and a Virtual Observatory compatible web enabled interface is under development.
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    Bar fraction in lenticular galaxies: Dependence on luminosity and environment
    (2010-10-15) Barway, Sudhanshu; Wadadekar, Yogesh; Kembhavi, A.K.
    We present a study of bars in lenticular galaxies based on a sample of 371 galaxies from the SDSS-DR 7 and 2MASS in optical and near-infrared bands, respectively. We found a bar in 15% of the lenticular galaxies in our sample, which is consistent with recent stud- ies. The barred galaxy fraction shows a luminosity dependence, with faint lenticular galaxies (MK > −24.5, total absolute magnitude in K band) having a larger fraction of bars than bright lenticular galaxies (MK < −24.5). A similar trend is seen when Mr = −21.5, the total absolute magnitude in SDSS r band is used to divide the sample into faint and bright lenticular galaxies.We find that faint galaxies in clusters show a higher bar fraction than their counterparts in the field. This suggests that the formation of bars in lenticular galaxies not only depends on the total luminosity of galaxy but also on the environment of the host galaxy.