81 research outputs found
Editorial. Sport in the Context of Migration and Health Crises
Recent crises, from the economic and migratory to the recent COVID-19 pandemic, have dramatically affected all areas of individual and collective life – and sport and physical activity are no exception. The main aim of this special issue is to bring researchers interested in sports and physical activity to propose their works. The focus of this special issue lays in the new challenges that sociology of sports and physical activity have to face to understand these new complex scenarios, the main issues we had to face, the successes, the criticalities and the lessons learned
Global and Regional IUCN Red List Assessments: 16
In this contribution, the conservation status assessment of three vascular plants according to IUCN categories and criteria are presented. It includes the assessment of Aubrieta columnae subsp. sicula, Calligonum zakirovii and Santolina decumbens subsp. tisoniana at global level
Global and Regional IUCN Red List Assessments: 16
In this contribution, the conservation status assessment of three vascular plants according to IUCN categories and criteria are presented. It includes the assessment of Aubrieta columnae subsp. sicula, Calligonum zakirovii and Santolina decumbens subsp. tisoniana at global level
The flaring blazars of the first 1.5 years of the AGILE mission
We report the AGILE gamma-ray observations and the results of the
multiwavelength campaigns on seven flaring blazars detected by the mission:
During two multiwavelength campaigns, we observed gamma-ray activity from two
Flat Spectrum Radio Quasars of the Virgo region, e.g. 3C 279 and 3C 273 (the
latter being the first extragalactic source simultaneously observed with the
gamma-ray telescope and the hard X ray imager of the mission). Due to the large
FOV of the AGILE/GRID instrument, we achieved an almost continuous coverage of
the FSRQ 3C 454.3. The source showed flux above 10E-6 photons/cm2/s (E > 100
MeV) and showed day by day variability during all the AGILE observing periods.
In the EGRET era, the source was found in high gamma-ray activity only once. An
other blazar, PKS 1510-089 was frequently found in high gamma-ray activity. S5
0716+71, an intermediate BL Lac object, exhibited a very high gamma-ray
activity and fast gamma-ray variability during a period of intense optical
activity. We observed high gamma-ray activity from W Comae, a BL Lac object,
and Mrk 421, an high energy peaked BL Lac object. For this source, a
multiwavelength campaign from optical to TeV has been performed
Detection of Gamma-ray Emission from the Eta-Carinae Region
We present the results of extensive observations by the gamma-ray AGILE
satellite of the Galactic region hosting the Carina nebula and the remarkable
colliding wind binary Eta Carinae (Eta Car) during the period 2007 July to 2009
January. We detect a gamma-ray source (1AGL J1043-5931) consistent with the
position of Eta Car. If 1AGL J1043-5931 is associated with the Eta Car system
our data provide the long sought first detection above 100 MeV of a colliding
wind binary. The average gamma-ray flux above 100 MeV and integrated over the
pre-periastron period 2007 July to 2008 October is F = (37 +/- 5) x 10-8 ph
cm-2 s-1 corresponding to an average gamma-ray luminosity of L = 3.4 x 10^34
erg s-1 for a distance of 2.3 kpc. We also report a 2-day gamma-ray flaring
episode of 1AGL J1043-5931 on 2008 Oct. 11-13 possibly related to a transient
acceleration and radiation episode of the strongly variable shock in the
system.Comment: 5 pages, 4 figure, accepted for publication in ApJ Letter
First AGILE Catalog of High Confidence Gamma-Ray Sources
We present the first catalog of high-confidence gamma-ray sources detected by
the AGILE satellite during observations performed from July 9, 2007 to June 30,
2008. Catalogued sources are detected by merging all the available data over
the entire time period. AGILE, launched in April 2007, is an ASI mission
devoted to gamma-ray observations in the 30 MeV - 50 GeV energy range, with
simultaneous X-ray imaging capability in the 18-60 keV band. This catalog is
based on Gamma-Ray Imaging Detector (GRID) data for energies greater than 100
MeV. For the first AGILE catalog we adopted a conservative analysis, with a
high-quality event filter optimized to select gamma-ray events within the
central zone of the instrument Field of View (radius of 40 degrees). This is a
significance-limited (4 sigma) catalog, and it is not a complete flux-limited
sample due to the non-uniform first year AGILE sky coverage. The catalog
includes 47 sources, 21 of which are associated with confirmed or candidate
pulsars, 13 with Blazars (7 FSRQ, 4 BL Lacs, 2 unknown type), 2 with HMXRBs, 2
with SNRs, 1 with a colliding-wind binary system, 8 with unidentified sources.Comment: Revised version, 15 pages, 3 figures, 3 tables. To be published in
Astronomy and Astrophysics. Text improved and clarified. Refined analysis of
complex regions of the Galactic plane yields a new list of high-confidence
sources including 47 sources (compared with the 40 sources appearing in the
first version
Multiwavelength observations of 3C 454.3 II. The AGILE 2007 December campaign
We report on the second AGILE multiwavelength campaign of the blazar 3C 454.3
during the first half of December 2007. This campaign involved AGILE, Spitzer,
Swift,Suzaku,the WEBT consortium,the REM and MITSuME telescopes,offering a
broad band coverage that allowed for a simultaneous sampling of the synchrotron
and inverse Compton (IC) emissions.The 2-week AGILE monitoring was accompanied
by radio to optical monitoring by WEBT and REM and by sparse observations in
mid-Infrared and soft/hard X-ray energy bands performed by means of Target of
Opportunity observations by Spitzer, Swift and Suzaku, respectively.The source
was detected with an average flux of~250x10^{-8}ph cm^-2s^-1 above 100
MeV,typical of its flaring states.The simultaneous optical and gamma-ray
monitoring allowed us to study the time-lag associated with the variability in
the two energy bands, resulting in a possible ~1-day delay of the gamma-ray
emission with respect to the optical one. From the simultaneous optical and
gamma-ray fast flare detected on December 12, we can constrain the delay
between the gamma-ray and optical emissions within 12 hours. Moreover, we
obtain three Spectral Energy Distributions (SEDs) with simultaneous data for
2007 December 5, 13, 15, characterized by the widest multifrequency coverage.
We found that a model with an external Compton on seed photons by a standard
disk and reprocessed by the Broad Line Regions does not describe in a
satisfactory way the SEDs of 2007 December 5, 13 and 15. An additional
contribution, possibly from the hot corona with T=10^6 K surrounding the jet,
is required to account simultaneously for the softness of the synchrotron and
the hardness of the inverse Compton emissions during those epochs.Comment: 13 pages, 8 figures, 2 tables, Accepted for publication in Ap
AGILE detection of extreme gamma-ray activity from the blazar PKS 1510-089 during March 2009. Multifrequency analysis
We report on the extreme gamma-ray activity from the FSRQ PKS 1510-089
observed by AGILE in March 2009. In the same period a radio-to-optical
monitoring of the source was provided by the GASP-WEBT and REM. Moreover,
several Swift ToO observations were triggered, adding important information on
the source behaviour from optical/UV to hard X-rays. We paid particular
attention to the calibration of the Swift/UVOT data to make it suitable to the
blazars spectra. Simultaneous observations from radio to gamma rays allowed us
to study in detail the correlation among the emission variability at different
frequencies and to investigate the mechanisms at work. In the period 9-30 March
2009, AGILE detected an average gamma-ray flux of (311+/-21)x10^-8 ph cm^-2
s^-1 for E>100 MeV, and a peak level of (702+/-131)x10^-8 ph cm^-2 s^-1 on
daily integration. The gamma-ray activity occurred during a period of
increasing activity from near-IR to UV, with a flaring episode detected on
26-27 March 2009, suggesting that a single mechanism is responsible for the
flux enhancement observed from near-IR to UV. By contrast, Swift/XRT
observations seem to show no clear correlation of the X-ray fluxes with the
optical and gamma-ray ones. However, the X-ray observations show a harder
photon index (1.3-1.6) with respect to most FSRQs and a hint of
harder-when-brighter behaviour, indicating the possible presence of a second
emission component at soft X-ray energies. Moreover, the broad band spectrum
from radio-to-UV confirmed the evidence of thermal features in the optical/UV
spectrum of PKS 1510-089 also during high gamma-ray state. On the other hand,
during 25-26 March 2009 a flat spectrum in the optical/UV energy band was
observed, suggesting an important contribution of the synchrotron emission in
this part of the spectrum during the brightest gamma-ray flare, therefore a
significant shift of the synchrotron peak.Comment: 13 pages, 7 figures, 3 tables. Accepted for publication in Astronomy
and Astrophysic
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