A5086966855- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Cosmology and Gravitation Theories
- Adaptive optics and wavefront sensing
- Radio Astronomy Observations and Technology
- History and Developments in Astronomy
- Solar and Space Plasma Dynamics
- Phase Equilibria and Thermodynamics
- Pulsars and Gravitational Waves Research
- Scientific Research and Discoveries
- Plant Water Relations and Carbon Dynamics
- Fluid Dynamics and Turbulent Flows
- Dark Matter and Cosmic Phenomena
- Astro and Planetary Science
- Statistical and numerical algorithms
- Meteorological Phenomena and Simulations
- Superconducting and THz Device Technology
- Spacecraft and Cryogenic Technologies
- Experimental and Theoretical Physics Studies
University of Groningen
2016-2025
Astronomical Institute of the Slovak Academy of Sciences
2004-2025
University of Bologna
2010-2019
Rijksmuseum
2019
University of Salerno
2010-2018
Leiden University
2017
GNA University
2000-2016
Netherlands Institute for Radio Astronomy
2003-2015
Astronomy and Space
2004-2015
University of Cape Town
2015
Evidence for the accretion of cold gas in galaxies has been rapidly accumulating past years. HI observations and their environment have brought to light new facts phenomena which are evidence ongoing or recent accretion: 1) A large number accompanied by gas-rich dwarfs surrounded cloud complexes, tails filaments. It may be regarded as direct local universe. is probably same kind phenomenon material infall stellar streams observed halos our galaxy M31. 2) Considerable amounts extra-planar...
We present |$^{3\small {D}}$|barolo,† a new code that derives rotation curves of galaxies from emission-line observations. This software fits 3D tilted-ring models to spectroscopic data cubes and can be used with variety observations: H i molecular lines optical/IR recombination lines. describe the structure main algorithm show it performs much better than standard 2D approach on velocity fields. A number successful applications, high very low spatial resolution are presented discussed....
We fit the rotation curves of isolated dwarf galaxies to directly measure stellar mass-halo mass relation ($M_*-M_{200}$) over range $5 \times 10^5 < M_{*}/{\rm M}_\odot 10^{8}$. By accounting for cusp-core transformations due feedback, we find a monotonic with little scatter. Such monotonicity implies that abundance matching should yield similar $M_*-M_{200}$ if cosmological model is correct. Using 'field galaxy' function from Sloan Digital Sky Survey (SDSS) and halo $Λ$ Cold Dark Matter...
The shape and diversity of dwarf galaxy rotation curves is at apparent odds with dark matter halos in a Λ Cold Dark Matter (ΛCDM) cosmology. We use mock data from isolated simulations to show that this owes three main effects. Firstly, stellar feedback heats matter, leading `coreNFW' density profile slowly rising curve. Secondly, if close recent starburst, large H i bubbles push the curve out equilibrium, deforming shape. Thirdly, when galaxies are viewed near face-on, their best fit...
We present H I observations of the edge-on galaxy NGC 891. These are among deepest ever performed on an external galaxy. They reveal a huge gaseous halo, much more extended than seen previously and containing almost 30% I. This halo shows structures various scales. On one side, there is filament extending (in projection) up to 22 kpc vertically from disk. Small (M ≳ 106 M⊙) clouds, some with forbidden (apparently counterrotating) velocities, also detected. The overall kinematics gas...
We present evidence for cosmological gas accretion on to spiral galaxies in the local universe. The is seen through its effects dynamics of extraplanar neutral gas. rates that we estimate two nearby are order their star formation rates. Our model shows most produced by supernova feedback (galactic fountain) and only 10–20 per cent comes from accretion. accreting material must have low specific angular momentum about disc's spin axis, although magnitude vector can be higher. also explore a...
High-sensitivity H I observations of the nearby spiral galaxy NGC 2403 obtained with VLA are presented and discussed. The properties extended, differentially rotating layer its holes, structure, outer warp described. In addition, these new data reveal presence a faint, kinematically anomalous component. This shows up in line profiles as extended wings emission toward systemic velocity. central regions very broad (up to 150 km s-1) indicate large deviations from circular motion. We have...
We introduce a new, very deep neutral hydrogen (HI) survey being performed with the Westerbork Synthesis Radio Telescope (WSRT). The Hydrogen Accretion in LOcal GAlaxieS (HALOGAS) Survey is producing an archive of some most sensitive HI observations available, on angular scales which are useful for studying faint, diffuse gas and around nearby galaxies. data used to perform careful modeling galaxies, characterizing their content, morphology, kinematics, primary goal revealing global...
We present a study of the distribution and kinematics neutral gas in low-inclination Scd galaxy NGC 6946. The has been observed for 192 h at 21-cm with Westerbork Synthesis Radio Telescope. These are among deepest observations ever obtained nearby galaxy. detect widespread high-velocity H I (up to about 100 km s-1) find 121 holes, most which located inner regions where density star formation rate higher. Much appears be related be, some cases, associated holes. overall is characterized by...
Observational evidence shows that low-redshift galaxies are surrounded by extended haloes of multiphase gas, the so-called 'circumgalactic medium' (CGM). To study survival relatively cool gas (T < 10^5 K) in CGM, we performed a set hydrodynamical simulations cold = 10^4 neutral clouds travelling through hot 2x10^6 and low-density (n 10^-4 cm^-3) coronal medium, typical Milky Way-like at large galactocentric distances (~ 50-150 kpc). We explored effects different initial values relative...
It is argued that galaxies like ours sustain their star formation by transferring gas from an extensive corona to the star-forming disc. The transfer effected galactic fountain – cool clouds are shot up plane kiloparsec heights above plane. Kelvin–Helmholtz instability strips these clouds. If pressure and metallicity of high enough, stripped causes a similar mass coronal condense in cloud's wake. Hydrodynamical simulations cloud–corona interaction presented. These confirm existence critical...
The spatial segregation between dSphs and dIrrs in the Local Group has long been regarded as evidence of an interaction with their host galaxies. In this paper, we assume that ram-pressure stripping is dominant mechanism removed gas from use to derive a lower bound on density corona Milky Way at large distances (50-90 kpc) Galactic centre. At same time, upper by demanding interstellar medium pressure equilibrium hot corona. We consider two dwarfs (Sextans Carina) well-determined orbits star...
We present the discovery of stellar tidal tails around Large and Small Magellanic Clouds in Gaia DR1 data. In between Clouds, their arms are stretched towards each other to form an almost continuous bridge. Our analysis relies on exquisite quality Gaia's photometric catalogue build detailed star-count maps Clouds. demonstrate that data can be used detect variable stars across whole sky, particular, RR Lyrae LMC SMC. Additionally, we use a combination Gale follow distribution Young Main...
We study the gas kinematics traced by 21-cm emission of a sample six HI$-$rich low surface brightness galaxies classified as ultra-diffuse (UDGs). Using 3D kinematic modelling code $\mathrm{^{3D}}$Barolo we derive robust circular velocities, revealing startling feature: UDGs are clear outliers from baryonic Tully-Fisher relation, with velocities much lower than similar mass. Notably, baryon fraction our UDG is consistent cosmological value: these compatible having no "missing baryons" within...
In star-forming galaxies, stellar feedback can have a dual effect on the circumgalactic medium both suppressing and stimulating gas accretion. The trigger of accretion be caused by disc material ejected into halo in form fountain clouds its interaction with surrounding hot corona. Indeed, at disc–corona interface, mixing between cold/metal-rich (T ≲ 104 K) coronal ≳ 106 dramatically reduce cooling time portion corona produce condensation We studied different galactic environments through...
We investigate the dynamics of starbursting dwarf galaxies, using both new and archival H I observations. consider 18 nearby galaxies that have been resolved into single stars by HST observations, providing their star formation history total stellar mass. find 9 objects a regularly rotating disk, 7 kinematically disturbed 2 show unsettled distributions. Two (NGC 5253 UGC 6456) velocity gradient along minor axis which we interpret as strong radial motions. For with disk derive rotation...
Dwarf Irregular galaxies (dIrrs) are the smallest stellar systems with extended HI discs. The study of kinematics such discs is a powerful tool to estimate total matter distribution at these very small scales. In this work, we 17 extracted from `Local Irregulars That Trace Luminosity Extremes, Nearby Galaxy Survey' (LITTLE THINGS). Our approach differs significantly previous studies in that directly fit 3D models (two spatial dimensions plus one spectral dimension) using software...
There is a large consensus that gas in high-$z$ galaxies highly turbulent, because of combination stellar feedback processes and gravitational instabilities driven by mergers accretion. In this paper, we present the analysis sample five Dusty Star Forming Galaxies (DSFGs) at $4 \lesssim z\lesssim 5$. Taking advantage magnifying power strong lensing, quantified their kinematic dynamical properties from ALMA observations [CII] emission line. We combined measurements obtained for these with...
Early assembly of a galaxy disk and bulge Galaxy formation in the early Universe is thought to have been chaotic process, producing disturbed asymmetric morphologies. Over billions years, galaxies dynamically relaxed form stable morphological features. Lelli et al. observed distant at redshift when was 1.2 billion years old (see Perspective by Wardlow). They used gas dust emission measure its kinematics, then modeled mass distribution within galaxy. The authors found that contains massive...
It is commonly believed that galaxies use, throughout the Hubble time, a very small fraction of baryons associated to their dark matter halos form stars. This so-called low "star formation efficiency" $f_\star\equiv M_\star/f_{\rm b} M_{\rm halo}$, where $f_{\rm b}\equiv\Omega_{\rm b}/\Omega_{\rm c}$ cosmological baryon fraction, expected reach its peak at nearly $L^\ast$ (at efficiency $\approx 20\%$) and decline steeply lower higher masses. We have tested this using sample nearby...
We imaged with ALMA and ARGOS/LUCI the molecular gas dust stellar continuum in XID2028, an obscured QSO at z=1.593, where presence of a massive outflow ionized component traced by [O III]5007 emission has been resolved up to 10 kpc. This target represents unique test case study 'feedback action' peak epoch AGN-galaxy coevolution. The detected CO(5-4) transition 1.3mm continuum, ~30 ~20 {\sigma} significance respectively, both emissions confined central (<4 kpc) radius area. Our analysis...
ABSTRACT We study the gas kinematics of a sample six isolated gas-rich low surface brightness galaxies, class called ultra-diffuse galaxies (UDGs). These have recently been shown to be outliers from baryonic Tully–Fisher relation (BTFR), as they rotate much slower than expected given their mass, and baryon fraction similar cosmological mean. By means 3D kinematic modelling fitting technique, we show that H i in our UDGs is distributed ‘thin’ regularly rotating discs determine rotation...
ABSTRACT We present new H i interferometric observations of the gas-rich ultra-diffuse galaxy AGC 114905, which previous work, based on low-resolution data, identified as an outlier baryonic Tully–Fisher relation. The observations, at a spatial resolution ∼2.5 times higher than before, reveal regular disc rotating about 23 km s−1. Our kinematic parameters, recovered with robust 3D modelling fitting technique, show that flat part rotation curve is reached. Intriguingly, can be explained...
The discovery of galaxies with regularly rotating discs at redshifts $\geq$ has been a puzzling challenge to galaxy formation models that tend predict chaotic gas kinematics in the early Universe as consequence accretion, mergers and efficient feedback. In this work, we investigated five highly resolved z $\sim$ 4.5 observed ALMA [CII] 158 $\mu$m emission line. sample is diverse: AzTEC1 (starburst galaxy), BRI1335-0417 quasar host J081740 (normal star-forming galaxy) SGP38326 (two starburst...