54 citations · 208 across the 21 of their papers we have counts for
21 papers
Two Peas in a Pod: The First Confirmed Dual Active Galactic Nucleus within a Green Pea Galaxy System
Konstantinos Kouroumpatzakis, Peter G. Boorman, Jiří Svoboda +5
The growth of galaxies in the early Universe is thought to be dominated by compact, intensely star-forming systems, yet the corresponding growth of supermassive black holes (SMBHs)…
Blueberry and Green Pea galaxies live in low density environments
Maitrayee Gupta, Jiří Svoboda, Konstantinos Kouroumpatzakis +3
Little is currently known about the large-scale environments of Green Pea (GP) and Blueberry (BB) galaxies, which are low-mass, compact systems with extreme specific star-formation…
HECATEv2: An all-sky galaxy catalogue for multimessenger astrophysics
E. Kyritsis, A. Zezas, K. Kovlakas +4
We present HECATEv2, the second release of the Heraklion Extragalactic Catalogue (HECATE), an all-sky, value-added galaxy catalogue comprising 204733 galaxies from the HyperLEDA da…
An automated activity classification tool for optical galaxy spectra
C. Daoutis, A. Zezas, E. Kyritsis +2
Reliable, versatile galaxy activity diagnostics are essential for understanding galaxy evolution. Traditional methods frequently necessitate extensive preprocessing, such as starli…
XMM-Newton Conclusively Identifies an Active Galactic Nucleus in a Green Pea Galaxy
Peter G. Boorman, Jiří Svoboda, Daniel Stern +23
Green Pea galaxies are a class of compact, low-mass, low-metallicity star-forming galaxies in the relatively local universe. They are believed to be analogues of high-redshift gala…
Gas excitation in galaxies and active galactic nuclei with He IIλ4686 and X-ray emission
K. Kouroumpatzakis, J. Svoboda
The origin of He II emission in galaxies remains a debated topic, requiring ionizing photons with energies exceeding 54 eV. While massive stars, such as Wolf-Rayet stars, have been…
From seagull to hummingbird: New diagnostic methods for resolving galaxy activity
C. Daoutis, A. Zezas, E. Kyritsis +2
Context. A major challenge in astrophysics is classifying galaxies by their activity. Current methods often require multiple diagnostics to capture the full range of galactic activ…
X-ray observations of Blueberry galaxies
B. Adamcová, J. Svoboda, E. Kyritsis +7
Compact star-forming galaxies were dominant galaxy types in the early Universe. Blueberry galaxies (BBs) represent their local analogues being very compact and having intensive sta…
Blueberry galaxies up to 200 Mpc and their optical and infrared properties
K. Kouroumpatzakis, J. Svoboda, A. Zezas +6
Dwarf highly star-forming galaxies (SFGs) dominated the early Universe and are considered the main driver of its reionization. However, direct observations of these distant galaxie…
Radio properties of Green Pea galaxies
Abhijeet Borkar, Romana Grossová, Jiří Svoboda +6
Green Peas (GPs) are young, compact, star-forming dwarf galaxies, and local (z~0.3) analogues of the early galaxies (z>6) considered to be mainly responsible for the reionisation o…
The extreme coronal line emitter AT 2022fpx: Varying optical polarization properties and late-time X-ray flare
Karri I. I. Koljonen, Ioannis Liodakis, Elina Lindfors +8
Supermassive black holes disrupt passing stars, producing outbursts called tidal disruption events (TDEs). TDEs have recently gained attention due to their unique dynamics and emis…
A versatile classification tool for galactic activity using optical and infrared colors
Charalampos Daoutis, Elias Kyritsis, Konstantinos Kouroumpatzakis +1
(abridged) The overwhelming majority of diagnostic tools for galactic activity are focused on active galaxies. Passive or dormant galaxies are often excluded from these diagnostics…
A versatile classification tool for galactic activity using optical and infrared colors
Elias Kyritsis, Charalampos Daoutis, Andreas Zezas +1
We use the Random Forest (RF) algorithm to develop a tool for automated activity classification of galaxies into 5 different classes: Star-forming (SF), AGN, LINER, Composite, and…
Star-formation rate and stellar mass calibrations based on infrared photometry and their dependence on stellar population age and extinction
Konstantinos Kouroumpatzakis, Andreas Zezas, Elias Kyritsis +2
The stellar mass () and the star-formation rate (SFR) are among the most important features that characterize galaxies. Measuring these fundamental properties accurately i…
Optical polarization from colliding stellar stream shocks in a tidal disruption event
I. Liodakis, K. I. I. Koljonen, D. Blinov +9
A tidal disruption event (TDE) occurs when a supermassive black hole rips apart a passing star. Part of the stellar material falls toward the black hole, forming an accretion disk…
The Star Formation Reference Survey-V: the effect of extinction, stellar mass, metallicity, and nuclear activity on star-formation rates based on H emission
Konstantinos Kouroumpatzakis, Andreas Zezas, Alexandros Maragkoudakis +5
We present new H photometry for the Star-Formation Reference Survey (SFRS), a representative sample of star-forming galaxies in the local Universe. Combining these data with the…
The Star Formation Reference Survey. IV. Stellar mass distribution of local star-forming galaxies
Paolo Bonfini, Andreas Zezas, Matthew L. N. Ashby +5
We constrain the mass distribution in nearby, star-forming galaxies with the Star Formation Reference Survey (SFRS), a galaxy sample constructed to be representative of all known c…
The Heraklion Extragalactic Catalogue (HECATE): a value-added galaxy catalogue for multi-messenger astrophysics
Konstantinos Kovlakas, Andreas Zezas, Jeff J. Andrews +6
We present the Heraklion Extragalactic Catalogue, or HECATE, an all-sky value-added galaxy catalogue, aiming to facilitate present and future multi-wavelength and multi-messenger s…
Metallicity and X-ray luminosity variations in NGC 922
Konstantinos Kouroumpatzakis, Andreas Zezas, Anna Wolter +3
We present a systematic study of the metallicity variations within the collisional ring galaxy NGC 922 based on long-slit optical spectroscopic observations. We find a metallicity…
Sub-galactic scaling relations between X-ray luminosity, star-formation rate, and stellar mass
Konstantinos Kouroumpatzakis, Andreas Zezas, Paul Sell +6
X-ray luminosity () originating from high-mass X-ray binaries (HMXBs) is tightly correlated with the host galaxy's star-formation rate (SFR). We explore this connection at sub…
Search for AGN counterparts of unidentified Fermi-LAT sources with optical polarimetry: Demonstration of the technique
N. Mandarakas, D. Blinov, I. Liodakis +12
The third Fermi-LAT catalog (3FGL) presented the data of the first four years of observations from the Fermi Gamma-ray Space Telescope mission. There are 3034 sources, 1010 of whic…