A5017401488- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Photocathodes and Microchannel Plates
- Astrophysics and Star Formation Studies
- Remote Sensing in Agriculture
- Calibration and Measurement Techniques
- Stellar, planetary, and galactic studies
- Remote Sensing and LiDAR Applications
- Advanced Vision and Imaging
- Scientific Research and Discoveries
- Mass Spectrometry Techniques and Applications
- History and Developments in Astronomy
- vaccines and immunoinformatics approaches
- Pulsars and Gravitational Waves Research
- Cosmology and Gravitation Theories
- Spectroscopy and Laser Applications
The University of Texas at Austin
2023-2025
Netherlands Institute for Radio Astronomy
2018-2023
University of Groningen
2018-2023
Astronomy and Space
2022
University of Zagreb
2016-2018
ABSTRACT Feedback from radio jets associated with active galactic nuclei (AGNs) plays a profound role in the evolution of galaxies. Kinetic power these appears to show temporal variation, but mechanism(s) responsible for this process are not yet clear. Recently, LOw Frequency ARray (LOFAR) has uncovered large populations active, remnant, and restarted jet populations. By focusing on LOFAR data Lockman Hole, work we use Radio AGNs Semi-Analytic Environments (RAiSE) dynamical model present...
We study the environment of 23 submillimetre galaxies (SMGs) drawn from JCMT/AzTEC 1.1mm S/N-limited sample in COSMOS field, as well 4 SMGs at z_spec>4.5, and 1 z_spec=2.49, yielding a 28 SMGs. search for overdensities using photometric redshifts based on over 30 UV-NIR bands, reaching an accuracy sigma(Delta z/(1+z))=0.0067 (0.0155) z<3.5 (>3.5). To identify we apply Voronoi tessellation analysis, estimate overdensity estimator delta_g function distance SMG and/or center. test validate our...
Abstract We present indirect constraints on the absolute escape fraction of ionizing photons ($f_{\rm esc}^{\rm LyC}$) system GN 42912 which comprises two luminous (MUV magnitudes −20.89 and −20.37) galaxies at z ∼ 7.5, 42912-NE 42912-SW, to determine their contribution photon budget Epoch Reionization (EoR). The high-resolution James Webb Space Telescope (JWST) NIRSpec NIRCam observations reveal they are separated by only $\sim 0{_{.}^{\prime\prime}}1$ (0.5 kpc) sky have a 358 km s−1...
Double-double radio galaxies (DDRGs) represent a short but unique phase in the life-cycle of some most powerful radio-loud active galactic nuclei (RLAGN). These display large-scale remnant plasma intergalactic medium left behind by past episode (AGN) activity, and meanwhile, jets have restarted new episode. The knowledge what causes to switch off restart is crucial our understanding galaxy evolution, while it important know if DDRGs form host dichotomy relative RLAGN. We utilised LOFAR...
Remnant radio galaxies represent an important phase in the life-cycle of active galactic nuclei. It is suggested that this phase, jets have switched off and extended emission fading rapidly. This not well-studied due to lack statistical samples observed at both low high frequencies. In work, we study a sample 23 candidate remnant previously selected using Low Frequency Array 150 MHz Lockman Hole field. We examine their morphologies spectral properties confirm nature revise morphological...
Abstract Active galactic nuclei (AGNs) can launch powerful jets that affect the gas properties in their host galaxies and influence star formation activity. Depending on powers lifetimes of surrounding medium, these remain confined within or close to galaxy at kiloparsec scales, grow giant radio megaparsec scales. We measure projected angular extents a complete sample 2,110 sources (z &lt; 2.5; S144MHz &gt; 600μJy) using νobs = 144 MHz images over 6.6 deg2 area Lockman Hole field...
Supermassive black holes at the centres of galaxies can cycle through periods activity and quiescence. Characterising duty active galactic nuclei is crucial for understanding impact energy they release on host galaxy. For radio AGN, this be done by identifying dying (remnant) restarted from their spectral properties. Using combination images 1400 MHz produced Apertif, new phased-array feed receiver installed Westerbork Synthesis Radio Telescope, 150 provided LOFAR, we have derived resolved...
Active galactic nuclei (AGN) at the centres of galaxies can cycle between periods activity and quiescence. Characterising duty-cycle AGN is crucial for understanding their impact on evolution host galaxy. For radio AGN, evolutionary stage be identified from a combination morphological spectral properties. We summarise results we have obtained in last few years by studying various phases lives, such as remnant restarted sources. used information derived LOw Frequency ARray (LOFAR) images 150...
Abstract Observations of low-ionization state metal lines provide crucial insights into the interstellar medium (ISM) galaxies, yet, disentangling physical processes responsible for emerging line profiles is difficult. This work investigates how mock spectra generated using a single galaxy in radiation-hydrodynamical simulation can help us interpret observations real galaxy. We create 22,500 C ii and Si from virtual at different times through multiple sight compare them with 45 low-redshift...
Radio galaxies are known to go through cycles of activity, where phases apparent quiescence can be followed by repeated activity the central supermassive black hole. A better understanding this cycle is crucial for ascertaining energetic impact that jets have on host galaxy, but little about it. We used deep LOFAR images at 150 MHz Lockman Hole extragalactic field select a sample 158 radio sources with sizes $> 60^{\prime\prime}$ in different their jet life cycle. Using variety criteria...
Remnant radio galaxies represent the dying phase of radio-loud active galactic nuclei (AGN). Large samples remnant are important for quantifying galaxy life cycle. The remnants AGN can be identified in sky surveys based on their spectral index, or, complementary, through visual inspection morphology. However, this is extremely time-consuming when applied to new large and sensitive surveys. Here we aim reduce amount required find morphology, supervised machine learning trained an existing...
The classification of the host galaxies radio sources in 25 deg$^2$ ultimate XMM extragalactic survey south field (XXL-S) is presented. XXL-S was surveyed at 2.1 GHz with Australia Telescope Compact Array (ATCA) and thus far largest area conducted down to rms flux densities $\sigma \sim 41$ $\mu$Jy beam$^{-1}$. Of 6287 XXL-S, 4758 (75.7%) were cross-matched an optical counterpart using likelihood ratio technique. There are 1110 spectroscopic redshifts 3648 photometric available for...
In this paper we present the optical, near-infrared (NIR) and X-ray identifications of 6287 radio sources detected in 2.1 GHz deep survey down to a median rms ~ 41microJy/beam obtained with Australia Telescope Compact Array (ATCA) XXL-S field. The goal is provide multi wavelength catalogue counterparts be used further studies. For optical NIR identification sources, likelihood ratio (LR) technique, slightly modified order take into account presence large number relatively bright close...
Context. Radio galaxies dominate the sky at radio wavelengths and represent an essential piece in galaxy evolution puzzle. High-resolution studies focussed on statistical samples of are expected to shed light triggering mechanisms active galactic nucleus their centre, alternating between phases activity quiescence. Aims. For this work, we zoomed sub-arcsec structures central regions 35 area covering 6.6 deg 2 Lockman Hole region. The sources studied here were previously classified as active,...
We study the space density evolution of active galactic nuclei (AGN) using 610 MHz radio survey XXL-North field, performed with Giant Metrewave Radio Telescope. The covers an area 30.4 deg 2 , a beamsize 6.5 arcsec. is divided into two parts, one covering 11.9 1 σ rms noise 200 μ Jy beam −1 and other spanning 18.5 45 . extracted catalog components above 7 was cross-matched multi-wavelength field (covering about 80% field) likelihood ratio method, which determines counterparts based on their...
The Low Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS) is a low-frequency radio continuum survey of the Northern sky at an unparalleled resolution and sensitivity. In order to fully exploit this huge dataset those produced by Square Kilometre in next decade, automated methods machine learning data-mining will be increasingly essential both for morphological classifications identifying optical counterparts sources. Using self-organising maps (SOMs), form unsupervised learning, we...
Recurrent phases of dormancy and activity occur in the supermassive black holes active galactic nuclei. Characterizing duty cycles this process is crucial understanding impact energy released on host galaxies, their evolution. However, it challenging to identify sources quiescent restarted phases. Our goal characterize a substantial sample radio galaxies phase explore idea core prominence as signature activity. We expand our prior study identifying from $30\ deg^2 $ area Lockman Hole larger...
(abridged) Characterizing duty cycles of recurrent phases dormancy and activity in supermassive black holes active galactic nuclei is crucial understanding impact energy released on host galaxies their evolution. However, identifying sources quiescent restarted challenging. Our goal to identify characterize a substantial sample radio phase explore core prominence as signature this activity. We expand our prior study from $30\,\mathrm{deg^2}$ area Lockman Hole larger $424\,\mathrm{deg^2}$...
We present indirect constraints on the absolute escape fraction of ionizing photons ($f_{\rm esc}^{\rm LyC}$) system GN 42912 which comprises two luminous galaxies ($M_{\rm UV}$ magnitudes -20.89 and -20.37) at $z\sim7.5$, 42912-NE 42912-SW, to determine their contribution photon budget Epoch Reionization (EoR). The high-resolution James Webb Space Telescope NIRSpec NIRCam observations reveal are separated by only ~0.1$"$ (0.5 kpc) sky have a 358 km s$^{-1}$ velocity separation. 42912-SW...
Radio galaxies are known to undergo phases of activity, where the stage after jets have switched off is referred as remnant phase. This state can be followed by a restarted phase when activity reignites. Remnant and radio sources important for testing models evolution active galactic nuclei (AGN) understanding impact recurrent jet has on their host galaxies. Although we now statistical samples in various stages life cycle, how this intermittent reflected optical properties sample not yet...
Observations of low-ionization state (LIS) metal lines provide crucial insights into the interstellar medium galaxies, yet, disentangling physical processes responsible for emerging line profiles is difficult. This work investigates how mock spectra generated using a single galaxy in radiation-hydrodynamical simulation can help us interpret observations real galaxy. We create 22,500 C II and Si from virtual at different times through multiple sight compare them with 45 low-redshift...
We combine the power of blind integral field spectroscopy from Hobby-Eberly Telescope (HET) Dark Energy Experiment (HETDEX) with sources detected by Low Frequency Array (LOFAR) to construct HETDEX-LOFAR Spectroscopic Redshift Catalog. Starting first data release LOFAR Two-metre Sky Survey (LoTSS), including a value-added catalog photometric redshifts, we extracted 28,705 HETDEX spectra. Using an automatic classifying algorithm, assigned each object star, galaxy, or quasar label along...
Abstract We combine the power of blind integral field spectroscopy from Hobby–Eberly Telescope (HET) Dark Energy Experiment (HETDEX) with sources detected by Low Frequency Array (LOFAR) to construct HETDEX-LOFAR Spectroscopic Redshift Catalog. Starting first data release LOFAR Two-metre Sky Survey, including a value-added catalog photometric redshifts, we extracted 28,705 HETDEX spectra. Using an automatic classifying algorithm, assigned each object star, galaxy, or quasar label along...
Remnant radio galaxies represent the dying phase of radio-loud active galactic nuclei (AGN). Large samples remnant are important for quantifying galaxy life cycle. The remnants AGN can be identified in sky surveys based on their spectral index, or, complementary, through visual inspection morphology. However, this is extremely time-consuming when applied to new large and sensitive surveys. Here we aim reduce amount required find morphology, supervised machine learning trained an existing...
Radio galaxies dominate the radio sky and are essential to galaxy evolution puzzle. High-resolution studies of statistical samples expected shed light on triggering mechanisms AGN, alternating between phases activity quiescence. In this work, we focus sub-arcsec structures in central regions 35 over 6.6 $deg^2$ Lockman Hole region. These sources were previously classified as active, remnant, candidate restarted using 150 MHz LOFAR observations. We examine morphologies study spectral...