A5056402031- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Neutrino Physics Research
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Particle Accelerators and Free-Electron Lasers
- Astronomical Observations and Instrumentation
- Gyrotron and Vacuum Electronics Research
- Molecular Spectroscopy and Structure
- Streptococcal Infections and Treatments
- Cosmology and Gravitation Theories
- Antenna Design and Optimization
- Astro and Planetary Science
- Superconducting and THz Device Technology
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- Relativity and Gravitational Theory
- Energy Harvesting in Wireless Networks
- Particle Detector Development and Performance
Konkoly Observatory
2016-2025
Research Centre for Astronomy and Earth Sciences
2016-2025
Eötvös Loránd University
2017-2025
Nicolaus Copernicus University
2025
Chinese Academy of Sciences
2008-2023
University of Oxford
2023
Czech Academy of Sciences, Institute of Physics
2023
Joint Institute for VLBI ERIC
2015-2022
Max Planck Institute for Astronomy
2022
South African Radio Astronomy Observatory
2022
We present the results of a series radio, optical, X-ray and gamma-ray observations BL Lac object S50716+714 carried out between April 2007 January 2011. The multi-frequency were obtained using several ground space based facilities. intense optical monitoring source reveals faster repetitive variations superimposed on long-term variability trend at time scale ~350 days. Episodes fast recur scales ~ 60-70 simultaneous activity frequencies favors SSC mechanism for production high-energy...
We report results from a 1 week multi-wavelength campaign to monitor the BL Lac object S5 0716+714 (on December 9-16, 2009). In radio bands source shows rapid (~ (0.5-1.5) day) intra-day variability with peak amplitudes of up ~ 10 %. The at 2.8 cm leads by about day 6 and 11 cm. This time lag more variations suggests an intrinsic contribution source's intraday cm, while interstellar scintillation (ISS) seems predominate. Large quasi-sinusoidal 0.8 mag were detected in V, R I-bands. X-ray...
Very long baseline interferometry (VLBI) allows for high-resolution and high-sensitivity observations of relativistic jets, that can reveal periodicities several years in their structure. We perform an analysis long-term VLBI data the quasar S5 1928+738 terms a geometric model helical structure projected onto plane sky. monitor direction jet axis through its inclination position angles. decompose variation inner 2 mas into periodic term with amplitude ∼0| $_{.}^{\circ}$|89 linear decreasing...
High-redshift radio-loud quasars are used to, among other things, test the predictions of cosmological models, set constraints on black hole growth in early Universe and understand galaxy evolution. Prior to this paper, 20 extragalactic radio sources at redshifts above 4.5 have been imaged with very long baseline interferometry (VLBI). Here, we report observations an additional ten z > 1.7 5 GHz European VLBI Network, thereby increasing number by 50 per cent. Combining our newly observed...
Aims. The BL Lac object S5 0716+71 was observed in a global multi-frequency campaign to search for rapid and correlated flux density variability signatures of an inverse-Compton (IC) catastrophe during the states extreme apparent brightness temperatures.
Abstract Many massive early-type galaxies host central radio sources and hot X-ray atmospheres indicating the presence of radio-mechanical active galactic nucleus (AGN) feedback. The duty cycle detailed physics radio-mode AGN feedback is still a matter debate. To address these questions, we present 1–2 GHz Karl G. Jansky Very Large Array observations sample 42 nearest optically brightest galaxies. We detect emission in 41/42 However, galaxy without source, NGC 499, has recently been detected...
ABSTRACT We present rest-frame optical JWST Near-infrared Spectrograph (NIRSpec) integral field unit (IFU) spectroscopy of TN J1338−1942 at z = 4.1, one the most luminous galaxies in early universe with powerful extended radio jets. Previous observations showed evidence for strong, large-scale outflows based on its large (∼150 kpc) halo detected Ly α, and high-velocity [O ii] emission features ground-based spectroscopy. Our NIRSpec/IFU spatially resolve line properties across host galaxy....
Context.Some intra-day variable, compact extra-galactic radio sources show brightness temperatures severely exceeding 1012 K, the limit set by catastrophic inverse-Compton (IC) cooling in of incoherent synchrotron radiation. The violation IC limit, actually possible under non-stationary conditions, would lead to avalanches soft-γ-ray energy band during transient periods.
Context: There are about 60 quasars known at redshifts z>5.7 to date. Only three of them detected in the radio above 1 mJy flux density 1.4 GHz frequency. Among them, J1429+5447 (z=6.21) is highest-redshift quasar present. These rare, distant, and powerful objects provide important insight into activity supermassive black holes Universe early cosmological epochs, on physical conditions their environment. Aims: We studied compact structure milli-arcsecond (mas) angular scale, order compare...
There is growing evidence of relativistic jets in radio-loud narrow-line Seyfert 1 (RL-NLS1) galaxies. We constrain the observational properties radio emission first RL-NLS1 galaxy ever detected gamma-rays, PMN J0948+0022, i.e., its flux density and structure total intensity polarization, compactness, variability. performed three real-time e-VLBI observations J0948+0022 at 22 GHz, using a global array including telescopes Europe, East Asia, Australia. These are science carried out with...
Context. Protoplanetary disks show large diversity regarding their morphology and dust composition. With mid-infrared interferometry the thermal emission of can be spatially resolved, distribution properties within studied. Aims. Our aim is to perform a statistical analysis on sample 82 around low- intermediate-mass young stars, based interferometric observations. We intend study disk sizes, variability, silicate mineralogy. Methods. Archival data from MIDI instrument VLTI are homogeneously...
Abstract High-redshift radio sources provide plentiful opportunities for studying the formation and evolution of early galaxies supermassive black holes. However, number known radio-loud active galactic nuclei (AGN) above redshift 4 is rather limited. At high redshifts, it appears that blazars, with relativistically beamed jets pointing toward observer, are in majority compared to misaligned respect line sight. To find more these AGN, milliarcsecond-scale imaging studies carried out very...
Abstract We report observations of a powerful ionized gas outflow in the z = 4.1 luminous radio galaxy TNJ1338-1942 hosting an obscured quasar using Near Infrared Spectrograph (NIRSpec) on board JWST. spatially resolve large-scale (∼15 kpc) and measure rates. The outflowing shows velocities exceeding 900 km s −1 broad line profiles with widths 1200 located at ∼10 kpc projected distance from central nucleus. nebula overlaps brightest lobe, indicating that jets are responsible for kinematics....
Circumstellar disks around stars older than 10 Myr are expected to be gas-poor. There are, however, two examples of old (30-40 Myr) debris-like containing a detectable amount cold CO gas. Here we present ALMA and Herschel Space Observatory observations one these disks, HD 21997, study the distribution origin dust its connection Our continuum images at 886um clearly resolve broad ring emission within diameter ~4.5 arcsec, adding 21997 dozen debris resolved (sub)millimeter wavelengths....
We investigate the pc-scale kinematics and kpc-scale radio morphology of quasar PG 1302-102, which may harbour a sub-pc separation supermassive binary black hole system at its centre as inferred from optical variability. High-resolution interferometric measurements obtained with Very Long Baseline Array (VLBA) in Monitoring Of Jets Active galactic nuclei VLBA Experiments (MOJAVE) programme 15 GHz 20 epochs spanning 17 years were analysed to structure. Archival observations Large (VLA) 1.4 5...
The radio source J0028+0035 is a recently discovered double–double galaxy at redshift z=0.398. Its relic outer lobes are separated by about 3′ in the sky, corresponding to ∼1 Mpc projected linear size. Inside this large-scale structure, inner pair of collinear span 100 kpc. In arcsec-resolution images J0028+0035, there central feature that offers intriguing possibility being resolved into pc-scale, third innermost lobes. This would make rare triple–double where traces three distinct episodes...
The radio source J0028+0035 is a recently discovered double--double galaxy at redshift z=0.398. Its relic outer lobes are separated by about 3' in the sky, corresponding to ~1 Mpc projected linear size. Inside this large-scale structure, inner pair of collinear span 100 kpc. In arcsec-resolution images J0028+0035, there central feature that offers intriguing possibility being resolved into pc-scale, third innermost lobes. This would make rare triple-double where traces three distinct...
Radio-loud active galactic nuclei (AGN) with their jets pointed close to our line of sight constitute the majority extragalactic $\gamma$-ray sources and significantly contribute radiation observed in even higher energy regime. The upcoming Cherenkov Telescope Array (CTA) is expected detect fainter TeV objects, leading an anticipated increase proportion non-blazar high-energy sources. Here we present results dual-frequency (1.7 5~GHz) European VLBI Network (EVN) enhanced Multi Element...
Compact radio sources, radio-emitting active galactic nuclei, are scarce objects, yet important as reference points for astrometric, astrophysical, and spacecraft navigation applications. We present over 3900 potential new compact sources derived from a cross- match between the Very Large Array Sky Survey (VLASS) catalogue recently published Quaia quasar catalogue. The VLASS provides list of individual identified at 3 GHz with flux densities ~ 1 mJy, while is Gaia optical astrometric by...
The dominant fraction of the extragalactic γ-ray sources are blazars, active galactic nuclei with jets inclined ata small angle to line sight. Apart from a few dozen narrow-line Seyfert 1 galaxies (NLS1) and number radio associated sources. identification requires multiwavelength follow-up observations since several candidates could reside within relatively large localisation area. source 4FGL 0959.6+4606 was originally galaxy. However, work suggested nearby NLS1 as more probable origin...
Areas of massive star formation are strongly influenced by stellar winds and supernovae, therefore, enhanced turbulent flows expected. We analyse high-quality Karl G. Jansky Very Large Array observations the neutral hydrogen gas content DDO43, a relatively nearby irregular dwarf galaxy. The line wings spectral lines, which provide insights into local velocity dispersion, investigated together with far-ultraviolet data, tracing emissions from star-forming regions. find very weak correlations...