A5049735588- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Superconducting and THz Device Technology
- Gamma-ray bursts and supernovae
- Scientific Research and Discoveries
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Antenna Design and Optimization
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- History and Developments in Astronomy
- Geomagnetism and Paleomagnetism Studies
- Computational Physics and Python Applications
- GNSS positioning and interference
- Advanced Frequency and Time Standards
- Cosmology and Gravitation Theories
- Advanced Thermodynamic Systems and Engines
- Magnetic Field Sensors Techniques
- Characterization and Applications of Magnetic Nanoparticles
Osservatorio Astronomico di Cagliari
2015-2024
National Institute for Astrophysics
2008-2023
Istituto di Radioastronomia di Bologna
2000-2021
Arcetri Astrophysical Observatory
2021
Institute of Astrophysics and Space Sciences
2021
Osservatorio Astrofisico di Catania
2021
Agenzia Spaziale Italiana
2021
Trieste Astronomical Observatory
2021
University of Bologna
2001-2016
Universität Hamburg
2016
The existence of magnetic fields associated with the intracluster medium in clusters galaxies is now well established through different methods analysis. Magnetic are investigated radio band from studies rotation measure polarized and synchrotron emission cluster-wide diffuse sources. Other techniques include X-ray inverse Compton cold fronts magneto hydrodynamic simulations. We review main issues that have led to our knowledge on galaxies. Observations show cluster at μG level, values up...
Clusters of galaxies, as the largest virialized systems in Universe, are ideal laboratories to study formation and evolution cosmic structures...(abridged)... Most detailed knowledge galaxy clusters has been obtained recent years from ICM through X-ray Astronomy. At same time, radio observations have proved that is mixed with non-thermal components, i.e. highly relativistic particles large-scale magnetic fields, detected their synchrotron emission. The properties these components increased...
The aim of the present work is to constrain Coma cluster magnetic field strength, its radial profile and power spectrum by comparing Faraday Rotation Measure (RM) images with numerical simulations field. We have analyzed polarization data for seven radio sources in observed Very Large Array at 3.6, 6 20 cm, derived Measures kiloparsec scale resolution. Random three dimensional models been simulated various values central intensity B_0 power-law slope eta, where eta indicates how scales...
Chandra observations of the merging galaxy cluster A520 reveal a prominent bow shock with M = 2.1. This is only second clear example substantially supersonic merger front in clusters. Comparison X-ray image that previously known radio halo reveals coincidence leading edge shock, offering an interesting experimental setup for determining role shocks generation. The apparently consists two spatially distinct parts, main turbulence-driven component and cap-like forward structure related to...
We present a numerical approach to investigate the relationship between magnetic fields and Faraday rotation effects in clusters of galaxies. can infer structure strength intra-cluster by comparing our simulations with observed polarization properties extended cluster radio sources such as galaxies halos. find observations require field which fluctuates over wide range spatial scales (at least one order magnitude). If several polarized are located at different projected positions galaxy...
Clusters of galaxies may contain cluster-wide, centrally located, diffuse radio sources, called halos. They have been found to show morphologies similar those the X-ray emission. To quantify this qualitative statement we performed a point-to-point comparison and emission for four clusters containing halos: Coma, Abell 2255, 2319, 2744. Our study leads linear relation between surface brightness in two clusters, namely 2255 In Coma A2319 brightnesses seem be related with sub-linear power law....
We present the study of five `dying' nearby radio galaxies belonging to WENSS minisurvey and B2 bright catalogs: WNB1734+6407, WNB1829+6911, WNB1851+5707, 0120+33, 1610+29. These sources have been selected on basis their extremely steep broad-band spectra. The modeling integrated spectra deep spectral index images obtained with VLA confirmed that in these central engine has ceased be active for a significant fraction lifetime although extended lobes not yet completely faded away. found...
The MeerKAT Fornax Survey maps the distribution and kinematics of atomic neutral hydrogen gas (HI) in nearby galaxy cluster using telescope. 12 deg^2 survey footprint covers central region out to ~ Rvir stretches 2 towards south west include NGC 1316 group. HI column density sensitivity (3 sigma over 25 km/s) ranges from 5e+19/cm^2 at a resolution 10" (~ 1 kpc 20 Mpc distance Fornax) down 1e+18/cm^2 1' 6 kpc), slightly below this level lowest 100" 10 kpc). mass 50 is 6e+5 Msun. velocity 1.4...
Deep Very Large Array radio observations confirm the presence of halo and relic sources in six clusters galaxies (A115, A520, A773, A1664, A2254, A2744) where a wide diffuse emission was previously found NRAO VLA Sky Survey. New images at 1.4 GHz these are presented X-ray data obtained from ROSAT archive analyzed. The properties hosting halos relics analyzed discussed. A correlation between power cluster gravitational mass is presented.
New radio data is presented for the rich cluster Abell 2163. The emission characterized by presence of a halo, which one most powerful and extended halos known so far. In NE peripheral region, we also detect diffuse elongated emission, classify as relic. A2163 very hot luminous in X-ray. Its central region probably highly non relaxed state, suggesting that this likely to be recent merger. existence halo confirms are associated with massive clusters, connection between merger processes....
We analyze Chandra temperature maps for a sample of clusters with high-quality radio halo data to study the origin halos. The includes A520, A665, A754, A773, A1914, A2163, A2218, A2319, and 1E 0657-56. present new all but two them (A520 A754). All these exhibit distorted X-ray morphology strong gas variations indicating ongoing mergers. Some clusters, e.g., 0657-56, previously reported spatial correlation between brightness hot regions. However, it is not general feature. While most mergers...
New radio data are presented for the clusters A401, A545, A754, A1914, A2219 and A2390, where presence of diffuse emission was suggested from images NRAO VLA Sky Survey. Sensitive these clusters, obtained with Very Large Array (VLA)at 20 cm confirm existence sources allow us to derive their fluxes intrinsic parameters.The correlation between halo power cluster X-ray luminosity is derived a large sample briefly discussed.
The goal of this work is to constrain the strength and structure magnetic field in nearby cluster galaxies A2255. At radio wavelengths A2255 characterized by presence a polarized halo at center, relic source periphery, several embedded galaxies. emission from all these sources modified Faraday rotation as it traverses magnetized intra-cluster medium. distribution can be used probe topology cluster. For purpose, we performed Very Large Array observations 3.6 6 cm four A2255, obtaining...
<i>Aims. <i/>We recently performed a study of sample relaxed, cooling core galaxy clusters with deep Very Large Array observations at 1.4 GHz. We find that in the central regions A1835, A2029, and Ophiuchus dominant radio is surrounded by diffuse low-brightness emission takes form mini-halo. Here we present results analysis extended these mini-halos. <i>Methods. <i/>In order to investigate morphological properties galaxies propose fit their azimuthally averaged brightness profile an...
A deep radio observation of the A2255 cluster galaxies has been carried out at 1.4 GHz with Very Large Array synthesis telescope. Thanks to excellent (u, v) coverage and sensitivity achieved by our observation, low brightness diffuse extended sources in (radio halo relic) have imaged unprecedented resolution dynamic range. We find that filamentary structures are strongly polarized. The fractional linear polarization reaches levels 20–40% magnetic fields appear ordered on scales ~400 kpc....
Aims. To study at multiple frequencies the radio emission arising from massive galaxy cluster MACS J0717.5+3745 (z=0.55). Known to be an extremely complex merger, system is uniquely suited for investigation of phenomena work in intra-cluster medium (ICM) during collisions. Methods. We use multi-frequency and multi-resolution data obtained with Very Large Array telescope, X-ray features revealed by Chandra, probe non-thermal thermal components ICM, their relations interactions. Results. The...
The Intra-Cluster Medium is characterized by thermal emission, and the presence of large scale magnetic fields. In some clusters galaxies a diffuse non-thermal emission also present, located at cluster center named radio halo. These sources indicate existence relativistic particles fields in volume. this paper we collect data on all known nearby halos (z < 0.4), to discuss their statistical properties investigate origin. We searched for published reduced new archive VLA increase number...
<i>Aims. <i/>The aim of the present work is to study radio properties double relics in Abell 1240 and 2345 framework relic formation models.<i>Methods. <i/>We new Very Large Array observations at 20 90 cm for these two clusters. We performed spectral index polarization analysis compared our results with expectations from theoretical models.<i>Results. presence cluster confirmed by observations. Double show morphology, index, values agreement “outgoing merger shocks” models. One shows a...
The goal of this work is to put constraints on the strength and structure magnetic field in cluster galaxies A2382. We investigate relationship between Faraday rotation effects cluster, using numerical simulations as a reference for observed polarization properties. For purpose we present Very Large Array observations at 20 cm 6 two polarized radio sources embedded A2382, obtained detailed measure images both them. simulated random three-dimensional models with different power spectra thus...
The aim of this work is to probe the magnetic field properties in relics and infall regions galaxy clusters using Faraday Rotation Measures. We present Very Large Array multi-frequency observations seven sources region South-West Coma cluster, where infalling group NGC4839 relic 1253+275 are located. Measure maps for observed derived analysed study Coma. discuss how interpret data by comparing mock rotation measures that produced simulating different 3-dimensional models. model gives best...
We study the intra-cluster magnetic field in poor galaxy cluster Abell 194 by complementing radio data, at different frequencies, with data optical and X-ray bands. analyze new total intensity polarization observations of obtained Sardinia Radio Telescope (SRT). use SRT combination archival Very Large Array to derive both spectral aging Rotation Measure (RM) images galaxies 3C40A 3C40B embedded 194. The analysis indicates that does not show a major recent merger, but rather agrees scenario...
[Abridged] The Sardinia Radio Telescope (SRT) is the new 64-m dish operated by INAF (Italy). Its active surface will allow us to observe at frequencies of up 116 GHz. At moment, three receivers, one per focal position, have been installed and tested. SRT was officially opened in October 2013, upon completion its technical commissioning phase. In this paper, we provide an overview main science drivers for SRT, describe outcomes from scientific telescope, discuss a set observations...
The Square Kilometre Array (SKA) will answer fundamental questions about the origin, evolution, properties, and influence of magnetic fields throughout Universe. Magnetic can illuminate phenomena as diverse star formation, galactic dynamics, fast radio bursts, active nuclei, large-scale structure, dark matter annihilation. Preparations for SKA are swiftly continuing worldwide, community is making tremendous observational progress in field cosmic magnetism using data from a powerful...