A5071991900- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Atmospheric Ozone and Climate
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Scientific Research and Discoveries
- Advanced Chemical Physics Studies
- Geophysics and Gravity Measurements
- Electromagnetic Compatibility and Noise Suppression
- Superconducting and THz Device Technology
- GNSS positioning and interference
- Ionosphere and magnetosphere dynamics
- Spacecraft and Cryogenic Technologies
- Influenza Virus Research Studies
- Streptococcal Infections and Treatments
- Cold Fusion and Nuclear Reactions
- Medical Imaging Techniques and Applications
Osservatorio Astronomico di Cagliari
2009-2024
Institute for Space Astrophysics and Planetology
2023
Center for Astrophysics Harvard & Smithsonian
2023
National Radio Astronomy Observatory
2023
National Institute for Astrophysics
2021-2022
Joint Institute for VLBI ERIC
2011-2019
Radboud University Nijmegen
2015-2019
Leiden University
2011-2019
Arcetri Astrophysical Observatory
2019
Chalmers University of Technology
2015-2019
Very long baseline interferometric (VLBI) localisations of repeating fast radio bursts (FRBs) have demonstrated a diversity local environments: from nearby star-forming regions to globular clusters. Here we report the VLBI localisation FRB 20201124A using an ad-hoc array dishes that also participate in European Network (EVN). In our campaign, detected 18 total at two separate epochs. By combining visibilities both observing epochs, were able localise with 1-$\sigma$ error 4.5 milliarcseconds...
Class II methanol masers are signs of massive young stellar objects (MYSOs). Recent findings show that MYSO accretion bursts cause flares these masers. Thus, maser monitoring can be used to identify such bursts. Burst-induced SED changes provide valuable information on a very intense phase high-mass star formation. In mid-January 2019, flare the G358.93-0.03 was reported. ALMA and SMA imaging resolved core forming region proved association with brightest continuum source MM1. However, no...
We present polarization observations of the 6.7-GHz methanol masers around massive protostar Cepheus A HW2 and its associated disc. The data were taken with Multi-Element Radio Linked Interferometer Network. maser is used to determine full three-dimensional magnetic field structure HW2. suggest that probe large-scale not isolated pockets a compressed field. find predominantly aligned along protostellar outflow perpendicular molecular dust From orientation measurements strength line sight, we...
Abstract We present (sub)millimeter imaging at 0.″5 resolution of the massive star-forming region G358.93−0.03 acquired in multiple epochs 2 and 3 months following recent flaring its 6.7 GHz CH OH maser emission. Using Submillimeter Array Atacama Large Millimeter/submillimeter Array, we have discovered 14 new Class II lines ranging frequency from 199 to 361 GHz, which originate mostly = 1 torsionally excited transitions include one transition. The latter detection provides first...
A debated topic in star formation theory is the role of magnetic fields during protostellar phase high-mass stars. It still unclear how influence and dynamics massive disks outflows. Most current information on close to protostars comes from polarized maser emissions, which allows us investigate field small scales by using very long-baseline interferometry. The star-forming region W75N contains three radio continuum sources (VLA1, VLA2, VLA3), at different evolutionary stages, associated...
The current paradigm of star formation through accretion disks, and magnetohydrodynamically driven gas ejections, predicts the development collimated outflows, rather than expansion without any preferential direction. We present radio continuum observations massive protostar W75N(B)-VLA 2, showing that it is a thermal, ionized wind has evolved in 18 years from compact source into an elongated one. This consistent with evolution associated expanding water-vapor maser shell, which changed...
NGC7538 is a complex massive star-forming region. The region composed of several radio continuum sources, one which IRS1, high-mass protostar, from 0.3 pc molecular bipolar outflow was detected. Several maser species have been detected around IRS1. CH3OH masers suggested to trace Keplerian-disk, while the H2O are almost aligned outflow. More recent results that hosts torus and potentially disk, but with different inclination than Keplerian-disk supposed be traced by masers. Tracing magnetic...
We want to study the velocity and magnetic field morphology in vicinity (<1000 AU) of a massive young stellar object (YSO), at very high spatial resolution (10-100 AU). performed milli-arcsecond polarimetric observations strong CH3OH maser emission observed an O-type YSO, G023.01-00.41. have combined this information with masing gas previously measured same angular resolution. analyse fields reference system defined by direction molecular outflow equatorial plane hot core its base, as...
Context. Polarized emission from masers is an excellent tool to study magnetic fields in maser sources. The linear polarization of the majority understood as interplay saturation and anisotropic pumping. However, for latter mechanism, no quantitative modeling has been presented yet. Aims. We aim construct a comprehensive model polarization, including both pumping effects on masers. Methods. extended regular (isotropic) excitation with dimension that describes molecular population alignments,...
Multiscale studies of the morphology and strength magnetic field are crucial to properly unveil its role relative importance in high-mass star cluster formation. G31.41+0.31 (G31) is a hub-filament system that hosts protocluster embedded hot molecular core (HMC). G31 one few sources showing clear hourglass on scales between 1000,au 100 au previous interferometric observations. This strongly suggests field-regulated collapse. To complete study properties this star-forming region, we carried...
The role of magnetic fields in the formation high-mass stars is still under debate, and recent measurements their orientation strength by using polarized maser emissions are contributing new insights. Masers polarization, particular 6.7-GHz methanol masers, one best probes field morphologies around massive protostars. Determining morphology an increasing number protostars at milliarcsecond resolution observing masers crucial to better understand star formation.The First EVN Group consists 4...
Aims: In order to test the nature of an (accretion) disk in vicinity Cepheus A HW2, we measured three-dimensional velocity field CH3OH maser spots, which are projected within 1000au HW2 object, with accuracy 0.1km/s. Methods: We made use European VLBI Network (EVN) image 6.7GHz emission towards 4.5 milli-arcsecond resolution (3au). observed at three epochs spaced by one year between 2013 and 2015. During last epoch, on mid-march 2015, benefited from new deployed Sardinia Radio Telescope....
<i>Context. <i/>The role of magnetic fields during the protostellar phase high-mass star-formation is a debated topic. In particular, it still unclear how influence formation and dynamic disks outflows. Most current information on close to protostars comes from H<sub>2<sub/>O OH maser observations. Recently, first 6.7 GHz methanol polarization observations were made, they reveal strong ordered fields.<i>Aims. morphology field needs be investigated small scales, which can only done using very...
Context. Very luminous extragalactic water masers, the megamasers, are associated with active galactic nuclei (AGN) in galaxies characterized by accretion disks, radio jets, and nuclear outflows. Weaker kilomasers, seem to be related mostly star formation activity, although possibility exists that some of these sources may belong weak tail AGN maser distribution.
Context. W75N(B) is a massive star-forming region that contains three radio continuum sources (VLA 1, VLA 2, and 3), which are thought to be young stellar objects at different evolutionary stages. 1 the most evolved 2 least source. The 22 GHz H2O masers associated with have been mapped several epochs over eight years. While in show persistent linear distribution along jet, those distributed around an expanding shell. Furthermore, maser polarimetric measurements revealed magnetic fields...
We report full polarimetric VLBA observations of water masers towards the Turner-Welch Object in W3(OH) high-mass star forming complex. This object drives a synchrotron jet, which is quite exceptional for protostar, and associated with strongly polarized maser source, W3(H$_2$O), making it an optimal target to investigate role magnetic fields on innermost scales protostellar disk-jet systems. The linearly emission from provides clues orientation local field, while measurement Zeeman...
Several radio sources have been detected in the HMSFR W75N(B), among them massive YSOs VLA1 and VLA2 are of great interest. These thought to be different evolutionary stages. In particular, is at early stage photoionization it driving a thermal jet, while thermal, collimated ionized wind surrounded by dusty disk or envelope. both 22 GHz water masers past. Those around show persistent distribution along jet those instead traced evolution from non-collimated outflow over period 20 years. By...
Context. Magnetic fields have only recently been included in theoretical simulations of high-mass star formation. The show that magnetic play an important role the formation and dynamics molecular outflows. Masers, particular 6.7-GHz CH3OH masers, are best probes field morphologies around massive young stellar objects on smallest scales 10–100 AU.