C. S. Buemi
A5043347295- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Solar and Space Plasma Dynamics
- Neutrino Physics Research
- Astro and Planetary Science
- Dark Matter and Cosmic Phenomena
- GNSS positioning and interference
- Particle Accelerators and Free-Electron Lasers
- Geophysics and Gravity Measurements
- Computational Physics and Python Applications
- Adaptive optics and wavefront sensing
- Cosmology and Gravitation Theories
- Ionosphere and magnetosphere dynamics
- History and Developments in Astronomy
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Radio Wave Propagation Studies
- Molecular Spectroscopy and Structure
Osservatorio Astrofisico di Catania
2015-2024
National Institute for Astrophysics
2006-2018
Institute for Space Astrophysics and Planetology
2007-2015
Istituto di Radioastronomia di Bologna
1996-2005
We present time-resolved broad-band observations of the quasar 3C 279 obtained from multi-wavelength campaigns conducted during first two years Fermi Gamma-ray Space Telescope mission. While investigating previously reported gamma-ray/optical flare accompanied by a change in optical polarization, we found that emission appears delayed with respect to gamma-ray about 10 days. X-ray reveal pair `isolated' flares separated ~90 days, only weak counterparts. The spectral structure measured...
Hi-GAL is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 $\mu$m. We present band-merged catalogue spatially matched sources their properties derived from fits to spectral energy distributions (SEDs) heliocentric distances, based on photometric catalogs presented Molinari et al. (2016a), covering portion plane $-71.0^{\circ}< \ell < 67.0^{\circ}$. The contains 100922 regular SED, 24584 which show $\mu$m counterpart are...
The radio quasar 3C 454.3 underwent an exceptional optical outburst lasting more than 1 year and culminating in spring 2005. maximum brightness detected was R = 12.0, which represents the most luminous state thus far observed (M_B ~ -31.4). In order to follow emission behaviour of source detail, a large multiwavelength campaign organized by Whole Earth Blazar Telescope (WEBT). Continuous optical, near-IR monitoring performed several bands. ToO pointings Chandra INTEGRAL satellites provided...
Context. The quasar 3C 279 is among the most extreme blazars in terms of luminosity and variability flux at all wavebands. Its variations polarization are quite complex therefore require intensive monitoring observations multiple wavebands to characterise interpret observed changes.
Aims. Since the CGRO operation in 1991–2000, one of primary unresolved questions about blazar γ-ray emission has been its possible correlation with low-energy (in particular optical) emission. To help answer this problem, Whole Earth Blazar Telescope (WEBT) consortium organized GLAST-AGILE Support Program (GASP) to provide optical-to-radio monitoring data be compared detections by AGILE and GLAST satellites. This new WEBT project started early September 2007, just before a strong detection...
We report on the multi-wavelength observations of PKS 1510-089 (a flat spectrum radio quasar (FSRQ) at z = 0.361) during its high activity period between 2008 September and 2009 June. During this 11 month period, source was characterized by a complex variability optical, UV, γ-ray bands, timescales down to 6–12 hr. The brightest isotropic luminosity, recorded March 26, ≃2 × 1048 erg s−1. in Fermi Large Area Telescope energy range shows mild curvature described well log-parabolic law, can be...
We report on 18 months of multiwavelength observations the blazar 3C 454.3 (Crazy Diamond) carried out in July 2007-January 2009. show results AGILE campaigns which took place May-June 2008, July-August and October 2008-January During May 2009 period, source average flux was highly variable, from an gamma-ray F(E>100MeV) > 200E-8 ph/cm2/s to F(E>100MeV)~80E-8 The spectrum between 100 MeV 1 GeV can be fit by a simple power law (Gamma_GRID ~ 2.0 2.2). Only 3-sigma upper limits derived 20-60...
In this paper, we present the analysis of incoherent non-thermal radio emission from a sample hot magnetic stars, ranging early-B to early-A spectral type. Spanning wide range stellar parameters and wind properties, these stars display commonality in their which presents new challenges scenario as originally conceived. It was thought that relativistic electrons, responsible for emission, originate current sheets formed where opens field lines. However, true mass-loss rates cooler are too...
We present a catalogue of extended radio sources from the SARAO MeerKAT Galactic Plane Survey (SMGPS). Compiled 56 survey tiles and covering approximately 500 deg^2 across first, third, fourth quadrants, includes 16534 diffuse with areas larger than 5 synthesised beams. Of them, 3891 (24% total) are confidently associated known radio-emitting objects in literature, such as regions, supernova remnants, planetary nebulae, luminous blue variables, Wolf-Rayet stars. A significant fraction...
Aims. The Whole Earth Blazar Telescope (WEBT) consortium has been monitoring the blazar 3C 454.3 from radio to optical bands since 2004 study its emission variability properties.
The blazar 3C 454.3 underwent an unprecedented optical outburst in spring 2005. This was first followed by a mm and then cm radio outburst, which peaked February 2006. We report on follow-up observations the WEBT to study multiwavelength emission post-outburst phase. XMM-Newton July December 2006 added information X-ray UV fluxes. source faint state. flux at higher frequencies showed fast decreasing trend, represents tail of big outburst. It quiescent state, common all frequencies. In...
The GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT) monitored BL Lacertae in 2008-2009 at radio, near-IR, and optical frequencies. During this period, high-energy observations were performed by XMM-Newton, Swift, Fermi. We analyse these data with particular attention to calibration Swift UV data, apply a helical jet model interpret source broad-band variability. GASP-WEBT show an flare 2008 February-March, oscillations several tenths mag on few-day time scale...
<i>Context. <i/>Since 2001, the radio quasar 3C 454.3 has undergone a period of high optical activity, culminating in brightest state ever observed, during 2004-2005 outburst. The Whole Earth Blazar Telescope (WEBT) consortium carried out several multifrequency campaigns to follow source behaviour.<i>Aims. <i/>The GLAST-AGILE Support Program (GASP) was born from WEBT provide long-term continuous optical-to-radio monitoring sample <i>γ<i/>-loud blazars, operation AGILE and GLAST (now known as...
Since 1997, BL Lacertae has undergone a phase of high optical activity, with the occurrence several prominent outbursts. Starting from 1999, Whole Earth Blazar Telescope (WEBT) consortium organized various multifrequency campaigns on this blazar, collecting tens thousands data points. One main issues in study huge dataset been search for correlations between and radio flux variations, possible periodicities light curves. The analysis assembled during first four (comprising also archival to...
We present multiwavelength observations of 3C 454.3 from April 2008 to March 2010. The radio optical data are mostly the GASP-WEBT, UV and X-ray Swift, gamma-ray AGILE Fermi satellites. improved calibration optical-UV UVOT OM instruments estimated Lyalpha flux disentangle contributions different components in this spectral region. reveal prominent variability above 8 GHz. In band, amplitude decreases with increasing frequency due a steadier radiation both broad line region an accretion disc....
We report on the extreme gamma-ray activity from FSRQ PKS 1510-089 observed by AGILE in March 2009. In same period a radio-to-optical monitoring of source was provided GASP-WEBT and REM. Moreover, several Swift ToO observations were triggered, adding important information behaviour optical/UV to hard X-rays. paid particular attention calibration Swift/UVOT data make it suitable blazars spectra. Simultaneous radio gamma rays allowed us study detail correlation among emission variability at...
The quasar-type blazar 4C 38.41 (B3 1633+382) experienced a large outburst in 2011, which was detected throughout the entire electromagnetic spectrum. We present results of low-energy multifrequency monitoring by GASP project WEBT consortium and collaborators, as well those spectropolarimetric/spectrophotometric at Steward Observatory. also analyse high-energy observations Swift Fermi satellites. In optical-UV band, several indicate that there is contribution from QSO-like emission...
Context.In spring 2005 the blazar 3C 454.3 was observed in an unprecedented bright state from near-IR to hard X-ray frequencies. A mm outburst peaked June–July 2005, and it followed by a flux increase at high radio
The quasar 3C 279 was the target of an extensive multiwavelength monitoring campaign from 2006 January through April. An optical-IR-radio by Whole Earth Blazar Telescope (WEBT) collaboration organized around target-of-opportunity X-ray and soft γ-ray observations with Chandra INTEGRAL in mid-January, additional coverage RXTE Swift XRT. In this paper we focus on results WEBT campaign. source exhibited substantial variability optical flux spectral shape, a characteristic timescale few days....
<i>Context. <i/>BL Lacertae is the prototype of blazar subclass named after it. Yet, it has occasionally shown a peculiar behaviour that questioned simple interpretation its broad-band emission in terms synchrotron plus self-Compton (SSC) radiation.<i>Aims. <i/>In 2007–2008 observing season we carried out new multiwavelength campaign Whole Earth Blazar Telescope (WEBT) on BL Lacertae, involving three pointings by XMM-Newton satellite July and December 2007, January 2008, to study properties,...
A multifrequency campaign on the BL Lac object PG 1553+113 was organized by Whole Earth Blazar Telescope (WEBT) in 2013 April-August, involving 19 optical, two near-IR, and three radio telescopes. The aim to study source behaviour at low energies during around high-energy observations Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes April-July. We also analyse UV X-ray data acquired Swift XMM-Newton satellites same period. WEBT satellite allow us detail synchrotron emission...
Aims.A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by Whole Earth Blazar Telescope (WEBT) in 2003–2005 to study variability properties of source.