Konstantinos Kolokythas
I am a radio-astronomer, currently a Postdoctoral Fellow at the Center for Space Research at North-West University (NWU) in Potchefstroom, South Africa. My work is related to the study of the evolution of galaxy groups and their Brightest Group Early-type members. Towards this effort I have analysed several legacy radio data from the Giant Metrewave Radio Telescope (GMRT) at 235/610 MHz and Very Large Array (VLA) 1.4 GHz data using AIPS and casa. My research involves the study of a complete volume-limited optically selected sample of groups of galaxies out to z=0.01 in order to characterize the radio-AGN population in groups, examine their impact on the intra-group gas and member galaxies and unveil the linking properties between jet energetics, feedback process and Active Galactic Nuclei in galaxy groups. Towards the new era, I am analyzing wide-band radio data from uGMRT and involved in the MeerKAT Galaxy Clusters L-Band Survey for the characterization of the diffuse radio emission in galaxy clusters.
'A historical journey in ancient Greek Astronomy and Philosophy'
Sky Theatre, Nehru Planetarium, Mumbai
08.09.2017
Previous Open Public Lecture
Upcoming events/talks
'AGN feedback and galaxy evolution in
nearby galaxy groups using CLoGS' ​​
​International Astronomical Union Symposia, IAUS 359: Galaxy Evolution and Feedback Across Different Environments
02-06 March 2020, Bento Goncalves, Brazil
LATEST NEWS
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May 2020
Evidence of AGN feedback and sloshing in the X-ray luminous NGC 1550 galaxy group
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Kolokythas K., O'Sullivan E., Simona Giacintucci, Diana M. Worrall, Mark Birkinshaw, Somak Raychaudhury, Cathy Horellou, Huib Intema and Ilani Loubser. et al., 2020 (Accepted for publication in MNRAS)
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My latest work is on NGC 1550 galaxy group and has been accepted for publication in MNRAS. It is a combined radio/Xray study of a previously considered 'relaxed group' that reveals evidence of sloshing motions and Active Galactic Nuclei (AGN) heating of the intragroup medium from a decaying asymetric jet radio source that we suggest is a result of a minor merger or infall of a galaxy about 33 Million years ago.
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July 2019
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The Complete Local Volume Groups Sample - III. Characteristics of group central radio galaxies in the Local Universe
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Kolokythas K., O'Sullivan E., Intema H. et al., 2019 (Published in MNRAS)
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This work follows up from paper II describing the radio properties of the dominant galaxies of the low-richness groups, and the sample as a whole. We find that 46 of the 53 Brightest Groups Early-type galaxies are detected in radio, of which 25% host radio jet sources and another 9% diffuse radio emission. We also find that there is a correlation between radio morphology and the evolutionary stage of the groups, with radio point sources being mainly found at the central galaxies of spiral-rich systemsand jet sources seen in central galaxies regardless of the group spiral fraction.
July 2018
The Complete Local Volume Groups Sample - II. A study of the Central Radio Galaxies in the High-Richness Sub-sample
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Kolokythas K., O'Sullivan E., Raychaudhury S. et al., 2018 (Accepted for publication in MNRAS)
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This work is a follow-up study of the radio properties of the dominant early-type galaxies in 26 galaxy groups in the Local Universe, of the high-richness subsample of the Complete Local-volume Groups Sample (CLoGS). It presents results from the combination of new 610 MHz and 235 MHz observations from the Giant Metrewave Radio Telescope (GMRT) and Very Large Array (VLA) survey data with X-rays from Chandra and XMM-Newton.
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February 2018
The origin of the X-ray, radio and HI structures in the NGC 5903 galaxy group
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O'Sullivan E., Kolokythas K., Kantharia N. et al., 2018 (Accepted for publication in MNRAS)
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This work is a study of NGC 5903 galaxy group, a nearby (~30 Mpc) system of ~30 members, dominated by the giant ellipticals NGC 5903 and NGC 5898 which contains two unusual structures: a ~110 kpc long H I filament crossing the NGC 5903 galaxy and a ~75 kpc wide diffuse, steep-spectrum radio source of unknown origin that overlaps NGC 5903 and appears to be partly enclosed by the H I filament. It is clear that galaxy interactions continue to play an important role in the development of this relatively highly evolved galaxy group where we discuss the origin of the correlated radio, X-ray and H I structures, either through an interaction-triggered active galactic nucleus (AGN) outburst with enthalpy 1.8x10^{57} erg, or via a high-velocity collision between a galaxy and the HI filament.
