International Summer Student Internships (ISSI)

Projects proposed for the summer 2021

1. Against all odds: an investigation of the one-sided extended radio sources from the ROGUE I catalog
   

   The theory of the formation of classical (double-lobed) radio sources with sizes ranging from parsec to mega-parsec scales mandate the presence of radio lobes on both sides of the optical host galaxy. The Radio sources associated with Optical Galaxies and having Extended and Unresolved morphologies I (ROGUE I) catalog lists the optical and radio morphologies of 32,616 radio sources classified through visual identification. This catalog is the largest of its kind that uses the Sloan Digital Sky Survey (SDSS) optical maps, Faint Images of Radio Sky at Twenty cm (FIRST), and NRAO Sky Survey (NVSS) radio maps to ascertain the respective morphologies. In this study, approximately 2,500 sources are found to have extended radio morphologies and surprisingly about 500 of them are found to have extended radio-emitting lobe ONLY on one side of the optical host galaxy. This project aims to explore the nature of these sources.
   
   In this project, we will use more sensitive and better angular resolution LOFAR maps at 150 MHz and the recently released VLA Sky Survey (VLASS) maps at 3 GHz to confirm the single-sided lobe of these sources. In addition, we will use optical emission-line diagnostics to measure the black hole mass, disk luminosity, etc. Finally, a comparison of these quantities will be made with similar size classical double radio sources.
   
   Within the scope of this project, the student will learn:
   
   1. strengths and weaknesses of sky survey programs conducted at different wavebands and how to use them to our advantage.
   2. cross-matching techniques to identify sources from different survey catalogs.
   3. understanding of the basic physics of radio source formation and evolution.
   
   This project is intended for one or at most two students. Basic knowledge of programming is desired. Depending on the outcome of the project, there is a possibility of publishing the results in an international journal. More information about the ROGUE project is available at http://rogue.oa.uj.edu.pl/.

2. Multiwavelength analysis of the structure of relativistic AGN jets
   

   The aim of this project is to analyze the structure of AGN jets. Since different physical processes can be responsible for radiation in different wavelengths, to study the physics of AGN jets it’s important to use multiwavelength observational data. The main accent will be made on Chandra data analysis, which requires the usage of special dedicated software. This software enables the general data preparation, the simulation of point spread function (PSF), making spatial, temporal, and spectral analysis of Chandra data. To analyze the detailed structure of the jet morphology the different techniques for restoring the image will be used: various deconvolution methods and forward-fitting algorithm for modeling the jet structure.

3. Analysis of the ELF data
   

   The project is intended to the analysis of the data from the World ELF Radiolocation Array (WERA), which was developed, installed, and is maintained by the Krakow ELF group. It operates in the Extremely Low Frequency (ELF) range, which enables determining the locations and parameters of atmospheric discharges generating electromagnetic waves in the Earth ionosphere waveguide. The various physical events that happen in the ionosphere can be seen in ELF data in the time and frequency domain. Such events are Terrestrial Gamma-ray Flashes (TGF), Solar Proton Events (SPE), Sudden Ionospheric Disturbances (SID), etc. The goal of this project is to analyze the signatures of such events in ELF data.

4. Periodicity analysis in astronomy
   

   The aim of the project is to familiarize the student with various techniques of inferring meaningful periods of recurring oscillations that various astronomical sources exhibit, typically via light curves: rotation of asteroids, modes of stars, the solar cycle, X-ray binaries, active galactic nuclei. Advantages and disadvantages, restrictions and limitations of the methods: Fourier spectrum, Lomb-Scargle periodogram, phase dispersion minimization, wavelet scalogram, will be considered, critically discussed and applied.
   
   Requirements: general knowledge of astronomy; basic knowledge of statistics; programming skills in python, R, or Mathematica.

5. Everything you always wanted to know about compact galaxy groups (but were afraid to ask)
   

   Compact galaxy groups constitute a phenomena-abundant class of galaxy systems. Violent interactions, and tidal outflows caused by them suggest that there is a possibility that inergalactic magnetised structures can be formed. And it is indeed the case: entities of this type have already been detected, eg. in HCG 15, or HCG 92 - as well as in compact groups that are not referenced in the HCG catalogue. Recently we have published a catalogue of these objects at 144 MHz, finding that a non-negligible fraction - around 15% - contains sources of intergalactic radio emission. There are still many issues, or problems that are left unresolved - and this is what we want to do now. The ideas we can try to work on include (choose one):
   
   1) Searching for magnetised tidal dwarf galaxies (TDG). As for now, only three of such are known - and despite the fact that TDGs form mostly in galaxy pairs, all those three were found in galaxy groups. The task is to try finding additional ones: checking if systems known for hosting TDGs are also emitting at radio frequencies, and if there is any emission linked to those TDGs;
   
   2) We know that infrared properties of galaxies in groups are special - we see a dearth of "normal" galaxies inside the groups, when starburst and "dead" ones are abundant. As there exists a close link between the radio and far infrared luminosity - the radio-FIR correlation - it would be a good idea to investigate if this relation is the same for the galaxies in groups compared to the field ones, or different;
   
   3) It's always a good idea to broaden the existing database of groups that host radio emission - and this can only be done by searching through the archive data. Pick up a few promising systems, take a look inside the NRAO archive, or NRAO Archive Survey - try to find out if this is anything interesting.
   
   
   The project is intended for one, or - at most - two students. The chosen one(s) will work on a project that can be extended into a publication that will be submitted to one of the leading astronomical journals (ApJ, MNRAS, or A&A).