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IGM Heating in Fossil Galaxy Groups

Miraghaei Jafari, Halimehossadat | 2014

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 47011 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Khosroshahi, Habib; Rahvar, Sohrab
  7. Abstract:
  8. Fossil galaxy groups, famed to have undisturbed inter-galactic gas due to lack of recent group scale mergers, are energetically and morphologically ideal environments to study the IGM heating. In this article, we study the role of active galactic nuclei in heating the IGM in a sample of five fossil galaxy groups by employing their GMRT observations at 610 MHz and 1.4 GHz. We find that only two of the dominant galaxies in fossil groups are associated with the radio lobes. We evaluate the PdV work of the radio lobes and their corresponding heating power and compare to the X-ray emission loss within cooling radius. Our results show that the power due to mechanical heating is not sufficiently high to suppress the cooling. We also considered shock and vortex heating and conduction as alternative heating sources. The 1.4 GHz and 610 MHz radio luminosities of fossil groups are compared to a sample of normal galaxy groups for the same BGGs stellar mass and total group stellar mass quantified using the K-band luminosity. It appears that the fossil BGGs are under luminous at 1.4 GHz and 610 MHz for a given BGG stellar mass, luminosity, in comparison to a general population of the groups. We also explore how the bolometric radio luminosity of fossil sample depends on clusters and groups characteristics. We find that fossil groups follow the strong cool core clusters, from HILFUGCS sample, as far as the large scale characteristics of the groups are taken into account, consistent with the relaxed and virialised nature of fossil galaxy groups
  9. Keywords:
  10. Radio Astronomy ; Active Galaxies ; Fossil Galaxy Groups ; Intergalactic Medium ; Radio Continuum

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