Conveners
Extragalactic astrophysics and cosmology
- Olena Torbaniuk
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Ms Aikaterini Niovi Triantafyllaki (Tartu Observatory, Tõravere, 61602 Tartu maakond, Estonia)27/04/2023, 12:10
Large concentrations of mass are now understood to be the products of a Hubble time’s worth of merging and accretion. This history is preserved in the outer regions of galaxies' halos, where the dynamical scales are longer. This makes it possible to preserve fossil records of these events in the form of longlasting substructures imprinted in the physical properties of their stellar...
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Mr Mateusz Rałowski (Jagiellonian University, Kraków, Poland)27/04/2023, 12:25
Recent studies have reported on a possible evolution of the covering factor (CF) with redshift. The goal of the presentation is to answer the question if this evolution is real or whether selection effects play an important role. The presented analysis was based on cross-matched multiwavelength photometrical data from the five major surveys (SDSS, GALEX, UKIDSS, WISE, Spitzer). A sample of...
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Dr Olga Avsajanishvili (E. Kharadze Georgian National Astrophysical Observatory, Tbilisi, Georgia)27/04/2023, 12:40
Cosmological models beyond the standard Lambda Cold Dark Matter (ΛCDM) scenario, namely the scalar field 𝝓CDM models are considered in this talk. The dynamics of the universe and the large-scale structure growth rate in these models in comparison with the standard spatially-flat ΛCDM model are investigated. Constraints on model parameters of 𝝓CDM models from various data sets are presented.
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Ms Subhrata Dey (Astronomical observatory of Jagiellonian University, Kraków , Poland)27/04/2023, 12:55
We present the detailed analysis of (U)LIRGs from ultraviolet through far-infrared to radio ($\sim$70\, MHz to $\sim$15\,GHz) bands. We derive the astrophysical properties through spectral energy distribution (SED) modeling using the Code Investigating GALaxy Emission (CIGALE) and UltraNest codes. The radio SEDs include our new observations at 325 and 610\,MHz from the GMRT and the...
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Ms Precious Sejake (University of Pretoria, Hatfield, Gauteng, South Africa)27/04/2023, 13:10
The GLEAM 4-Jy (G4Jy) Sample, formed from the GLEAM survey, comprises 1,863 of the brightest extragalactic radio-sources in the southern sky, the vast majority of which are active galactic nuclei with powerful radio jets. However, 140 of these sources have uncharacterised/ambiguous host galaxies due to the inadequate resolution (of 25 to 45-arcsec) of existing radio images. In this talk, I...
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Ms Arpita Misra (Astronomical Observatory of the Jagiellonian University, Kraków, Poland)27/04/2023, 13:40
The morphological evolution of winged radio galaxies are explained using several theoretical models, including galaxy mergers. However, such a direct link between a perturbed radio morphology and a galaxy merger remains observationally sparse. Here we investigate a unique X-shaped radio galaxy J1159+5820, whose host displays the optical signature of a post merger system. Multifrequency radio...
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Mr Keegan Trehaeven (Rhodes University, Makhanda 6140, Eastern Cape, South Africa)27/04/2023, 13:55
Radio mini-halos are clouds of diffuse, low surface brightness synchrotron emission that surround the Brightest Cluster Galaxy (BCG) in massive cool-core galaxy clusters. In this paper, we use third generation calibration (3GC), also called direction-dependent (DD) calibration, and point source subtraction on MeerKAT extragalactic continuum data. We calibrate and image archival MeerKAT L-band...
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Mr Mykola Hradov (Faculty of Physics, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine)27/04/2023, 14:10
In our project we investigate the long term relaxation processes in the initially equilibrium self gravitating stellar systems. As an initial condition for our model star cluster we use the well described and well studied Plummer mass distribution (Plummer, 1911, MNRAS, 71, 460). We try to cover a wide range of observable stellar clusters in our Galaxy, so we generate the models starting from...
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Mr Luis Suelves (National Center for Nuclear Research, Poland)27/04/2023, 14:25
On our research we attempt to identify galaxy mergers in modern galaxy surveys. The main results we want to show in this presentation is how we used Machine Learning (ML) to learn a previously unknown photometric property of galaxy mergers.
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We built a Neural Network that we trained on photometric measurements from SDSS, using a class-balanced dataset composed by mergers from Darg et al.... -
Ms Mosima Portia Masipa27/04/2023, 14:40
Semi-numerical simulations are the leading candidates for evolving reionization on cosmological scales. These semi-numerical models are efficient in generating large-scale maps of the 21cm signal, but they are too slow to enable inference at the field level. We present different strategies to train machine learning models to accelerate these simulations. We derive the ionization field directly...
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Dr Artem Poliszczuk (Stanford University, USA)27/04/2023, 14:55
"The aim of this presentation is to show how machine learning techniques can be used
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for the task of object selection in multiwavelength photometric data. Here, I present a model for automatic active galactic nuclei (AGN) selection in the combined optical and near-IR photometric catalog based on the data from the deep sky survey in the AKARI NEP-Wide field. Specific construction of the...