A5035594789- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Adaptive optics and wavefront sensing
- Genomics and Rare Diseases
- Obstructive Sleep Apnea Research
- Sleep and related disorders
- Sleep and Wakefulness Research
- Genetic Syndromes and Imprinting
- GNSS positioning and interference
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
Leiden University
2019-2024
California Institute of Technology
2024
Klinik Barmelweid
2022
Stichting Epilepsie Instellingen Nederland
2022
Leiden University Medical Center
2022
Recent studies fueled doubts as to whether all currently defined central disorders of hypersomnolence are stable entities, especially narcolepsy type 2 and idiopathic hypersomnia. New reliable biomarkers needed, the question arises current diagnostic criteria should be reassessed. The main aim this data-driven observational study was see algorithms would segregate 1 identify more subgrouping individuals without cataplexy with new clinical biomarkers.We used agglomerative hierarchical...
We discover what is in projection the largest known structure of galactic origin: a giant radio galaxy with projected proper length $4.99 \pm 0.04\ \mathrm{Mpc}$. The source, named Alcyoneus, was first identified low-resolution LOFAR Two-metre Sky Survey images from which angularly compact sources had been removed. Being an extreme example its class, Alcyoneus could shed light on main mechanisms that drive growth. find - beyond geometry and host appear suspiciously ordinary: total...
Context. The Low Frequency Array (LOFAR) is the only existing radio interferometer able to observe at ultra-low frequencies (<100 MHz) with high resolution (<15") and sensitivity (<1 mJy beam −1 ). To exploit these capabilities, LOFAR Surveys Key Science Project using Band Antenna (LBA) carry out a sensitive wide-area survey 41–66 MHz named LBA Sky Survey (LoLSS). Aims. LoLSS covering whole northern sky above declination 24° of 15" 1–2 (1 σ ) depending on declination, field...
Large-scale sky surveys at low frequencies, like the LOFAR Two-metre Sky Survey (LoTSS), allow for detection and characterisation of unprecedented numbers giant radio galaxies (GRGs, or 'giants'). In this work, by automating creation radio--optical catalogues, we aim to significantly expand census known giants. We then combine sample with a forward model constrain GRG properties cosmological interest. particular, automate source component association through machine learning optical host...
To test the hypothesis that megaparsec-scale giant radio galaxies (GRGs) experience multiple epochs of recurrent activity leading to their sizes and understand nature double-double (DDRGs), we have built largest sample DDRGs from LOFAR Two Metre Sky Survey (LoTSS) data release 2. This comprises 111 sources, including 76 newly identified DDRGs, with redshifts ranging 0.06 1.6 projected between 0.7 Mpc 3.3 Mpc. We conducted a detailed analysis characterise properties, arm-length ratios, flux...
Radio galaxies are luminous structures created by the jets of supermassive black holes, and consist atomic nuclei, relativistic electrons, magnetic fields. In exceptional cases, radio attain cosmological, megaparsec extents - thus turn into giants. Giants embody most extreme known mechanism through which can impact Cosmic Web around them. The triggers giant growth remain a mystery. Excitingly, new sensitive low-frequency sky surveys hold promise to change this situation. work, we perform...
Giant radio galaxies (GRGs, giant RGs, or giants) are megaparsec-scale, jet-driven outflows from accretion disks of supermassive black holes, and represent the most extreme pathway by which can impact Cosmic Web around them. A long-standing but unresolved question is why giants so much larger than other galaxies. It has been proposed that, in addition to having higher jet powers might live especially low-density environments. In this work, we aim test hypothesis pinpointing Local Universe...
The Low Frequency Array (LOFAR) is the only existing radio interferometer able to observe at ultra-low frequencies (<100 MHz) with high resolution (<15") and sensitivity (<1 mJy/beam). To exploit these capabilities, LOFAR Surveys Key Science Project using Band Antenna (LBA) carry out a sensitive wide-area survey 41-66 MHz named LBA Sky Survey (LoLSS). LoLSS covering whole northern sky above declination 24 deg of 15" 1-2 mJy/beam (1 sigma) depending on declination, field properties,...
<title>Abstract</title> Jets launched by supermassive black holes transport relativistic leptons, magnetic fields, and atomic nuclei from the centres of galaxies to their outskirts beyond. These outflows embody most energetic pathway which respond Cosmic Web environment. Studying hole feedback is an astrophysical frontier, providing insights on star formation, galaxy cluster stability, origin cosmic rays, magnetism, heavy elements throughout Universe. This feedback’s cosmological importance...
Calibrating for direction-dependent ionospheric distortions in visibility data is one of the main technical challenges that must be overcome to advance low-frequency radio astronomy. In this paper, we propose a novel probabilistic, tomographic approach utilises Gaussian processes calibrate phase interferometric data. We suggest free electron density can modelled good approximation by process restricted thick single layer, and show under assumption differential total content also process....
Context. The detection of synchrotron radiation from the intergalactic medium (IGM) that pervades filaments Cosmic Web constitutes an upcoming frontier to test physical models astrophysical shocks and their mechanisms, trace missing baryons, constrain magnetogenesis – origin evolution extragalactic magnetic fields. Aims. first detections IGM within have recently been claimed. Now is time develop a rigorous statistical framework predict sky regions with strongest signal move mere inference,...
The warm-hot intergalactic medium (warm-hot IGM, or WHIM) pervades the filaments of Cosmic Web and harbours half Universe's baryons. WHIM's thermodynamic properties are notoriously hard to measure. Here we estimate a galaxy group - WHIM boundary temperature using new method. In particular, use radio image giant (giant RG, GRG) created by NGC 6185, massive nearby spiral. We analyse this extraordinary object with Bayesian 3D lobe model deduce an equipartition pressure $P_\mathrm{eq} = 6 \cdot...