A5034366398- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Real-time simulation and control systems
- Particle Detector Development and Performance
- Neutrino Physics Research
- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Calibration and Measurement Techniques
- Particle physics theoretical and experimental studies
- Geophysics and Gravity Measurements
- Electromagnetic Fields and Biological Effects
- Seismic Waves and Analysis
- Particle Accelerators and Free-Electron Lasers
- Metallurgical Processes and Thermodynamics
- Atmospheric and Environmental Gas Dynamics
- Scientific Research and Discoveries
- Solar and Space Plasma Dynamics
Max Planck Institute for Astronomy
2023-2025
Osservatorio di Astrofisica e Scienza dello Spazio
2023-2025
Brera Astronomical Observatory
2018-2023
University of Insubria
2018-2023
We present the discovery of PSO J030947.49+271757.31, radio brightest (23.7 mJy at 1.4 GHz) active galactic nucleus (AGN) z>6.0. It was selected by cross-matching NRAO VLA Sky Survey and Panoramic Telescope Rapid Response System PS1 databases its high-z nature confirmed a dedicated spectroscopic observation Large Binocular Telescope. A pointed Neil Gehrels $Swift$ Observatory XRT allowed us to measure flux $\sim$3.4$\times$10$^{-14}$ erg s$^{-1}$ cm$^{-2}$ in [0.5-10] keV energy band, which...
The Euclid ERO showcase Euclid's capabilities in advance of its main mission by targeting 17 astronomical objects, including galaxy clusters, nearby galaxies, globular and star-forming regions. A total 24 hours observing time was allocated the early months operation, scientific community engaged through an public data release. We describe development pipeline to create visually compelling images while simultaneously meeting demands within launch leveraging a pragmatic data-driven strategy....
We report on the direct observation of an extended X-ray jet in z = 6.1 radio-loud active galactic nucleus PSO J030947.49+271757.31 from a deep Chandra (128 ksec). This detection represents most distant kiloparsec-scale off-nuclear emission resolved X-rays to date. The angular distance is ∼4″ (corresponding ∼20 kpc at 6.1), along same direction observed parsec scales previous VLBA high-resolution radio observations. Moreover, 0.5–7.0 keV isophotes coincide with as imaged by VLA Sky Survey 3...
Abstract Blazars are radio-loud active galactic nuclei whose jets have a very small angle to our line of sight. Observationally, the radio emissions mostly compact or compact-core with one-sided jet. With 2.″5 resolution at 3 GHz, Very Large Array Sky Survey (VLASS) enables us resolve structure some blazar candidates in sky north decl. −40°. We introduce an algorithm classify sources as either blazar-like non-blazar-like based on their morphology VLASS images. apply three existing catalogs,...
High redshift blazars are an important class of Active Galactic Nuclei (AGN) that can provide independent estimate the supermassive black-hole mass function in high radio-loud AGN without bias due to absorption along line-of-sight. Using Cosmic Lens All Sky Survey (CLASS) we built a complete radio flux-limited sample (z>4) suitable for statistical studies. By combining dedicated optical observations and SDSS spectroscopic database, obtained 26 blazar candidates with above 4. On basis their...
We present the X-ray analysis of largest flux-limited complete sample blazar candidates at z>4 selected from Cosmic Lens All Sky Survey (CLASS). After obtaining a nearly (24/25) coverage (from Swift-XRT, XMM-Newton and Chandra), we analysed spectra in order to identify bona-fide blazars. classified sources based on shape their Spectral Energy Distributions (SEDs) and, particular, flatness emission its intensity compared optical one. then these high-z blazars with lower redshifts (z~1). found...
Abstract With enough X-ray flux to be detected in a 160 s scan by SRG/eROSITA, the z = 6.19 quasar CFHQS J142952+544717 is, far, most luminous source known at > 6. We present deep (245 ks) NuSTAR observations of this source; with ∼180 net counts combined observations, is distant object ever observed observatory. Fortuitously, was independently Chandra ∼110 days earlier, enabling identification two nearby (30″ and 45″ away), fainter sources. jointly fit both observations—self-consistently...
With enough X-ray flux to be detected in a 160s scan by SRG/eROSITA, the $z = 6.19$ quasar CFHQS J142952+544717 is, far, most luminous source known at > 6$. We present deep (245 ks) NuSTAR observations of this source; with $\sim180$ net counts combined observations, is distant object ever observed observatory. Fortuitously, was independently Chandra $\sim110$ days earlier, enabling identification two nearby (30'' and 45'' away), fainter sources. jointly fit both...
X-ray observations of the optically selected $z=6.025$ QSO CFHQS J164121+375520 (hereafter J1641) revealed that its flux dropped by a factor $\gtrsim7$ from 2018, when it was bright and soft source, to 2021. Such strong variability amplitude has not been observed before among $z>6$ QSOs, underlying physical mechanism unclear. We carried out new rest-frame UV monitoring campaign J1641 over 2022-2024. detected with Chandra in 2-7 keV band, while no significant emission is at softer energies,...
X-ray observations of the optically selected z=6.025 quasi-stellar object (QSO) CFHQS J164121+375520 (hereafter J1641) revealed that its flux dropped by a factor ≳7 between 2018, when it was bright and soft source, 2021. Such strong variability amplitude has not been observed before among z>6 QSOs, underlying physical mechanism unclear. We carried out new rest-frame UV monitoring campaign J1641 over 2022--2024. detected with in 2--7 keV band, while no significant emission is at softer...
Abstract We present optical and near-infrared (NIR) spectroscopic observations for a sample of 45 quasars at 6.50 < z ≤ 7.64 with absolute magnitudes 1450 Åin the range −28.82 M1450 −24.13 their composite spectrum. The median redshift in are zmedian = 6.71 $M_{1450,\rm {median}} \simeq -26.1$, respectively. NIR spectra taken echelle spectrographs, complemented additional data from long slit instruments, then reduced consistently using open-source Python-based reduction pipeline...
<title>Abstract</title> The existence of abundant post-starburst/quiescent galaxies just ∼1–2 Gyrs after the Big Bang challenges our current paradigm galaxy evolution. Cosmological simulations suggest that quasar feedback is likely most promising mechanism responsible for such rapid quenching. Here we report a high detection rate (6/27) exceptionally fast and powerful galaxy-scale outflows traced by [O III] emission in z ∼ 5–6 luminous quasars as revealed James Webb Space Telescope (JWST),...
ABSTRACT We present the selection of high-redshift (z ≳ 5.7) radio-loud (RL) quasi-stellar object (QSO) candidates from combination radio Rapid ASKAP Continuum Survey (RACS; at 888 MHz) and optical/near-infrared Dark Energy (DES). In particular, we selected six brighter than $S_{\rm 888\, MHz}\gt 1$ mJy beam−1 mag(zDES) &lt; 21.3 using dropout technique (in i-band). From this sample, were able to confirm high-z nature ∼ 6.1) two sources, which are now among highest redshift RL QSOs...
The recent detection of the quasi-stellar object (QSO) VIKING J231818.3$-$311346 (hereafter VIK J2318$-$3113) at redshift $z=6.44$ in Rapid ASKAP Continuum Survey (RACS) uncovered its radio-loud nature, making it one most distant known to date this class. By using data from several radio surveys Galaxy and Mass Assembly 23$^\mathrm{h}$ field dedicated follow-up, we were able constrain spectrum J2318$-$3113 observed range $\sim$0.1--10 GHz. At high frequencies (0.888--5.5 GHz frame) QSO...
Context. Obscuration in high-redshift quasi-stellar objects (QSOs) has a profound impact on our understanding of the evolution supermassive black holes across cosmic time. An accurate quantification its relevance is therefore mandatory. Aims. We present study aimed at evaluating importance obscuration jetted QSOs, that is, active nuclei characterised by presence powerful relativistic jets. Methods. compared observed number radio-detected QSOs different radio flux density limits with value...
The Spektrum-Roentgen-Gamma (SRG)/extended Roentgen Survey with an Imaging Telescope Array (eROSITA) All-Sky (eRASS) is expected to contain $ quasars that emitted their light when the universe was less than a billion years old, is, at $z>5.6$. By selection, these populate bright end of active galactic nuclei (AGN) X-ray luminosity function, and space density offers powerful demographic diagnostic parent super-massive black hole (SMBH) population. Of 400$ have been discovered $z>5.6$...
We report on a LUCI/Large Binocular Telescope near-infrared (NIR) spectrum of PSO J030947.49+271757.31 (hereafter J0309+27), the highest redshift blazar known to date (z$\sim$6.1). From C$\rm IV$$\lambda$1549 broad emission line we found that J0309+27 is powered by 1.45$^{+1.89}_{-0.85}$$\times$10$^9$M$_{\odot}$ supermassive black hole (SMBH) with bolometric luminosity $\sim$8$\times$10$^{46}$ erg s$^{-1}$ and an Eddington ratio equal 0.44$^{+0.78}_{-0.35}$. also obtained new photometric...
Context. The determination of the relative frequency active galactic nuclei (AGN) versus other spectral classes, for example, HII region-like (HII), transition objects (TRAN), passive (PAS), and retired (RET), in a complete set galaxies local Universe is primary importance to discriminate source ionization nuclear region galaxies. Aims. Here we aim provide spectroscopic characterization belonging Herschel Reference Survey (HRS), volume magnitude limited sample representative Universe, which...
We present the discovery and properties of DESJ014132.4-542749.9 (DES0141-54), a new powerful radio-loud active galactic nucleus (AGN) in early Universe (z=5.0). It was discovered by cross-matching first data release Dark Energy Survey (DES DR1) with Sidney University Molonglo (SUMSS) radio catalog at 0.843 GHz. This object is AGN high redshift DES. The DES0141-54, namely its very large radio-loudness (R>10$^{4}$), luminosity (L$_{0.8 GHz}$=1.73$\times$10$^{28}$ W Hz$^{-1}$), flatness...
We present Director’s Discretionary Time multi-frequency observations obtained with the Jansky Very Large Array and Long Baseline (VLBA) of blazar PSO J030947.49+271757.31 (hereafter J0309+27) at z = 6.10 ± 0.03. The milliarcsecond angular resolution our VLBA 1.5, 5, 8.4 GHz unveils a bright one-sided jet extended for ∼500 parsecs in projection. This high- radio-loud active galactic nucleus is resolved into multiple compact sub-components that are embedded more diffuse faint radio emission...
Different works have recently found an increase of the average X-ray-to-radio luminosity ratio with redshift in blazar population. We evaluate here whether inverse Compton interaction between relativistic electrons within jet and photons Cosmic Microwave Background (IC/CMB) can explain this trend. Moreover, we test IC/CMB model also be at origin different space density evolutions X-ray radio selected samples. By considering best statistically complete samples blazars or band covering a large...
Relativistic jets are thought to play a crucial role in the formation of massive galaxies and supermassive black holes. Here we report multi-wavelength multi-epoch observations quasar VLASSJ0410-0139 at redshift z=7, powered by 7e8 solar-mass hole. Its radio variability, X-ray properties, compact emission on parsec scales reveal that J0410-0139 is blazar with relativistic jet aligned our line sight. This blazar's existence implies many more similar (unaligned) jetted sources must exist z=7....
Abstract Relativistic jets are thought to play a crucial role in the formation and evolution of massive galaxies supermassive black holes. Blazars, which quasars with aligned along our line sight, provide insights into jetted population have been observed up redshifts z = 6.1. Here, we report discovery multi-wavelength characterization blazar VLASS J041009.05−013919.88 at 7 (age Universe ~750 Myr), is powered by ~7 × 10 8 M ⊙ hole. The presence this high-redshift implies large similar but...
Abstract Active galactic nuclei (AGN) have been observed as far redshift $z \sim 7$ . They are crucial in investigating the early Universe well growth of supermassive black holes at their centres. Radio-loud AGN with jets seen a small viewing angle called blazars and show relativistic boosting emission. Thus, apparently brighter easier to detect high-redshift Universe. DES J014132.4–542749.9 is radio-luminous but X-ray weak blazar candidate = 5$ We conducted high-resolution radio...
We present the low-frequency radio spectra of nine high-redshift quasars at 5.6 ≤ z 6.6 using Giant Metre Radio Telescope band-3, -4, and -5 observations (∼300−1200 MHz), archival Low Frequency Array (LOFAR; 144 Very Large (VLA; 1.4 3 GHz) data. Five in our sample have been discovered recently, representing some highest redshift bright known low frequencies. model their to study emission mechanism age jets by constraining spectral turnover caused synchrotron self-absorption (SSA) or...