983 research outputs found
Contribución al conocimiento de la flora de Andalucía: citas novedosas e interesantes de la provincia de Almería
Contribution to the knowledge about Andalusian flora: new and interesting cites of the Almería province.Palabras clave. Corología, Isla de Alborán, sureste ibérico, xenófitas.Key words. Corology, Alborán Island, South-Eastern Iberian Peninsula, xenophytes
Nueva citas para la flora de la provincia de Almería (Sureste Ibérico, España)
Three new floristic records are presented in this work including one new species for Andalucia (Tamarix dalmatica), one new species for the province of Almería (Filago hispanica) and a confirmation for this province (Orobanche ballotae).Se presentan tres citas florísticas que suponen, una novedad para Andalucía (Tamarix dalmatica), una novedad la provincia de Almería (Filago hispanica) y una confirmación para dicha provincia (Orobanche ballotae)
Global and Regional IUCN Red List Assessments: 3
In this contribution, the conservation status assessment of four vascular plants are presented according to IUCN categories and criteria. It includes the assessment at global level of Crepis lacera Ten subsp. titani (Pamp.) Roma-Marzio, G.Astuti & Peruzzi and Anthyllis hermanniae L. subsp. sicula Brullo & Giusso and the regional assessment of Commicarpus plumbagineus (Cav.) Standl. (Spain and Europe) and Ambrosia maritima L. (Italy)
The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab Nebula
MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in
the Canary island of La Palma, Spain. During summer 2011 and 2012 it underwent
a series of upgrades, involving the exchange of the MAGIC-I camera and its
trigger system, as well as the upgrade of the readout system of both
telescopes. We use observations of the Crab Nebula taken at low and medium
zenith angles to assess the key performance parameters of the MAGIC stereo
system. For low zenith angle observations, the standard trigger threshold of
the MAGIC telescopes is ~50GeV. The integral sensitivity for point-like sources
with Crab Nebula-like spectrum above 220GeV is (0.66+/-0.03)% of Crab Nebula
flux in 50 h of observations. The angular resolution, defined as the sigma of a
2-dimensional Gaussian distribution, at those energies is < 0.07 degree, while
the energy resolution is 16%. We also re-evaluate the effect of the systematic
uncertainty on the data taken with the MAGIC telescopes after the upgrade. We
estimate that the systematic uncertainties can be divided in the following
components: < 15% in energy scale, 11-18% in flux normalization and +/-0.15 for
the energy spectrum power-law slope.Comment: 21 pages, 25 figures, accepted for publication in Astroparticle
Physic
Limits to dark matter annihilation cross-section from a combined analysis of MAGIC and Fermi-LAT observations of dwarf satellite galaxies
We present the first joint analysis of gamma-ray data from the MAGIC
Cherenkov telescopes and the Fermi Large Area Telescope (LAT) to search for
gamma-ray signals from dark matter annihilation in dwarf satellite galaxies. We
combine 158 hours of Segue 1 observations with MAGIC with 6-year observations
of 15 dwarf satellite galaxies by the Fermi-LAT. We obtain limits on the
annihilation cross-section for dark matter particle masses between 10 GeV and
100 TeV - the widest mass range ever explored by a single gamma-ray analysis.
These limits improve on previously published Fermi-LAT and MAGIC results by up
to a factor of two at certain masses. Our new inclusive analysis approach is
completely generic and can be used to perform a global, sensitivity-optimized
dark matter search by combining data from present and future gamma-ray and
neutrino detectors.Comment: 19 pages, 3 figures. V2: Few typos corrected and references added.
Matches published version JCAP 02 (2016) 03
MAGIC observations of MWC 656, the only known Be/BH system
Context: MWC 656 has recently been established as the first observationally
detected high-mass X-ray binary system containing a Be star and a black hole
(BH). The system has been associated with a gamma-ray flaring event detected by
the AGILE satellite in July 2010. Aims: Our aim is to evaluate if the MWC 656
gamma-ray emission extends to very high energy (VHE > 100 GeV) gamma rays.
Methods. We have observed MWC 656 with the MAGIC telescopes for 23 hours
during two observation periods: between May and June 2012 and June 2013. During
the last period, observations were performed contemporaneously with X-ray
(XMM-Newton) and optical (STELLA) instruments. Results: We have not detected
the MWC 656 binary system at TeV energies with the MAGIC Telescopes in either
of the two campaigns carried out. Upper limits (ULs) to the integral flux above
300 GeV have been set, as well as differential ULs at a level of 5% of
the Crab Nebula flux. The results obtained from the MAGIC observations do not
support persistent emission of very high energy gamma rays from this system at
a level of 2.4% the Crab flux.Comment: Accepted for publication in A&A. 5 pages, 2 figures, 2 table
Multi-Wavelength Observations of the Blazar 1ES 1011+496 in Spring 2008
The BL Lac object 1ES 1011+496 was discovered at Very High Energy gamma-rays
by MAGIC in spring 2007. Before that the source was little studied in different
wavelengths. Therefore a multi-wavelength (MWL) campaign was organized in
spring 2008. Along MAGIC, the MWL campaign included the Metsahovi radio
observatory, Bell and KVA optical telescopes and the Swift and AGILE
satellites. MAGIC observations span from March to May, 2008 for a total of 27.9
hours, of which 19.4 hours remained after quality cuts. The light curve showed
no significant variability. The differential VHE spectrum could be described
with a power-law function. Both results were similar to those obtained during
the discovery. Swift XRT observations revealed an X-ray flare, characterized by
a harder when brighter trend, as is typical for high synchrotron peak BL Lac
objects (HBL). Strong optical variability was found during the campaign, but no
conclusion on the connection between the optical and VHE gamma-ray bands could
be drawn. The contemporaneous SED shows a synchrotron dominated source, unlike
concluded in previous work based on nonsimultaneous data, and is well described
by a standard one zone synchrotron self Compton model. We also performed a
study on the source classification. While the optical and X-ray data taken
during our campaign show typical characteristics of an HBL, we suggest, based
on archival data, that 1ES 1011+496 is actually a borderline case between
intermediate and high synchrotron peak frequency BL Lac objects.Comment: 13 pages, accepted for publication in MNRA
Detection of very high energy gamma-ray emission from the gravitationally-lensed blazar QSO B0218+357 with the MAGIC telescopes
Context. QSO B0218+357 is a gravitationally lensed blazar located at a
redshift of 0.944. The gravitational lensing splits the emitted radiation into
two components, spatially indistinguishable by gamma-ray instruments, but
separated by a 10-12 day delay. In July 2014, QSO B0218+357 experienced a
violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes.
Aims. The spectral energy distribution of QSO B0218+357 can give information on
the energetics of z ~ 1 very high energy gamma- ray sources. Moreover the
gamma-ray emission can also be used as a probe of the extragalactic background
light at z ~ 1. Methods. MAGIC performed observations of QSO B0218+357 during
the expected arrival time of the delayed component of the emission. The MAGIC
and Fermi-LAT observations were accompanied by quasi-simultaneous optical data
from the KVA telescope and X-ray observations by Swift-XRT. We construct a
multiwavelength spectral energy distribution of QSO B0218+357 and use it to
model the source. The GeV and sub-TeV data, obtained by Fermi-LAT and MAGIC,
are used to set constraints on the extragalactic background light. Results.
Very high energy gamma-ray emission was detected from the direction of QSO
B0218+357 by the MAGIC telescopes during the expected time of arrival of the
trailing component of the flare, making it the farthest very high energy
gamma-ray sources detected to date. The observed emission spans the energy
range from 65 to 175 GeV. The combined MAGIC and Fermi-LAT spectral energy
distribution of QSO B0218+357 is consistent with current extragalactic
background light models. The broad band emission can be modeled in the
framework of a two zone external Compton scenario, where the GeV emission comes
from an emission region in the jet, located outside the broad line region.Comment: 11 pages, 6 figures, accepted for publication in A&
Investigating the peculiar emission from the new VHE gamma-ray source H1722+119
The MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes observed
the BL Lac object H1722+119 (redshift unknown) for six consecutive nights
between 2013 May 17 and 22, for a total of 12.5 h. The observations were
triggered by high activity in the optical band measured by the KVA (Kungliga
Vetenskapsakademien) telescope. The source was for the first time detected in
the very high energy (VHE, GeV) -ray band with a statistical
significance of 5.9 . The integral flux above 150 GeV is estimated to
be per cent of the Crab Nebula flux. We used contemporaneous
high energy (HE, 100 MeV GeV) -ray observations from
Fermi-LAT (Large Area Telescope) to estimate the redshift of the source. Within
the framework of the current extragalactic background light models, we estimate
the redshift to be . Additionally, we used contemporaneous
X-ray to radio data collected by the instruments on board the Swift satellite,
the KVA, and the OVRO (Owens Valley Radio Observatory) telescope to study
multifrequency characteristics of the source. We found no significant temporal
variability of the flux in the HE and VHE bands. The flux in the optical and
radio wavebands, on the other hand, did vary with different patterns. The
spectral energy distribution (SED) of H1722+119 shows surprising behaviour in
the Hz frequency range. It can be modelled
using an inhomogeneous helical jet synchrotron self-Compton model.Comment: 12 pages, 5 figures, 2 table
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