132 research outputs found
Descobreixen un nou sistema binari de raigs-gamma a la nostra galàxia
No full textL'equip de col∙laboració del telescopi espacial Fermi-LAT, integrat entre altres pels científics de l'Institut de Ciències de l'Espai (CSIC-IEEC), amb seu a la UAB, Andrea Caliandro, Daniela Hadasch i Diego Torres, ha descobert un nou sistema binari de raigs gamma en els voltants del centre Galàctic. El descobriment ha merescut la publicació de l'estudi a la prestigiosa revista Science ja que a dia d'avui, només es coneixen uns quants sistemes que emeten en raigs gamma.El equipo de colaboración del telescopio espacial Fermi-LAT, integrado entre otros por los científicos del Instituto de Ciencias del Espacio (CSIC-IEEC), ubicado en el campus de la UAB, Andrea Caliandro, Daniela Hadasch y Diego Torres, han descubierto un nuevo sistema binario de rayos gamma en los inmediaciones del Centro Galáctico tal descubrimiento ha merecido la publicación del estudio en la prestigiosa revista Science ya que a día de hoy, solo se conocen un puñado de sistemas que emiten en rayos gamma
LS I +61 303 and LS5039 behavior in the high energy regime during two years of Fermi monitoring
No full textGamma-ray emission of young stellar objects and discovery of superorbital variability at high energies
No full textSe puede dividir mi tesis en tres partes: 1. Estudios de la emisi.n gamma de los sistemas binarios LS I +61 303 y LS 5039 a altas energ.as con el Fermi Large Area Telescope (LAT) y el primer descubrimiento de variabilidad superorbital a altas energ.as de la fuente LS I +61 303 Los sistemas binarios de rayos gamma son sistemas estelares cuyo espectro tiene su máximo a altas energías (sin tener en cuenta su emisión térmica). Ha sido detectada desde radio hasta rayos gamma (TeV), el sistema binario LS I +61 303 es muy variable en todas las frecuencias. Una característica de la variabilidad de este sistema es la modulación de su emisión a 26.496 días que coincide con su período orbital. En esta tesis mostramos por primera vez que la emisión gamma de LS I +61 303 presenta también una variabilidad superorbital con un período de 1667 días. Esta modulación es más presente en fases orbitales alrededor de apastro, aunque no introduce un cambio visible cerca de periastro. Además, se observa una aparición y desaparición de la variabilidad orbital en el espectro de potencias de los datos. Este comportamiento se puede explicar por una evolución cuasi-°©‐cíclica del disco ecuatorial de la estrella acompañante (estrella Be) cuyas características influyen en las condiciones para generar rayos gamma. Estos descubrimientos abren por primera vez la posibilidad de usar observaciones de rayos gamma para estudiar los discos de estrellas masivas en sistemas binarios excéntricos. 2. Estudios de la emisi.n gamma de magnetares a altas y muy altas energ.as con el LAT y con los telescopios Cherenkov MAGIC Los magnetares son una clase particular de estrellas de neutrones que muestran emisión desde radio hasta unos centenares de keV. Se pueden caracterizar por sus explosiones de rayos X y por sus perdidas de energía, las cuales son demasiado pequeñas para justificar su luminosidad en rayos X. Por esta razón, la teoría más aceptada es que la emisión X de la estrella de neutrones está suministrada por el decaimiento y las inestabilidades de sus altos campos magnéticos. En esta tesis, estos objetos han sido estudiados por primera vez a altas y a muy altas energías con el LAT y con los telescopios MAGIC. Hemos impuesto las primeras cotas a la posible emisión gamma de estos objetos. Además, este fuerte diagnóstico observacional fuerza una revisión del espacio de parámetros aplicable a la visibilidad del modelo de “outer gap” de Cheng & Zhang (2001) and Zhang & Cheng (2002) para cada magnetar. 3. Predicciones para la astronom.a Cherenkov con los telescopios CTA La siguiente generación de telescopios Cherenkov será CTA. Este experimento está ahora en la fase de diseño. En esta tesis, evaluamos las capacidades de CTA para estudiar la física no-°©‐térmica de sistemas binarios de rayos gamma. Eso requiere la observación de fenómenos a altas energías a tiempos y a escalas espaciales diferentes. Para hacer eso, hemos estudiado los sistemas binarios de rayos gamma en el contexto de la física conocida o esperada de estas fuentes. CTA será capaz de demostrar los procesos físicos detrás de la emisión gamma en sistemas binarios con una resolución espectral, temporal y espacial alta. Además crecerá el número de fuentes detectadas significativamente. Hemos observado que la sensibilidad de CTA conseguirá un muestreo de curvas de luz y espectros a escalas de tiempo muy cortas de alta calidad. Además, se podrá monitorear fuentes a tiempo largo usando una parte de los telescopios que todavía alcanzará una sensibilidad 2 o 3 veces mayor que cualquier instrumento actual operando a muy altas energías. En particular, es notable que CTA reducirá la indeterminación de los flujos e índices espectrales en unos cuantos factores.My
thesis
can
be
divided
into
three
parts:
1. Study
of
the
gamma-ray
emission
of
the
binary
systems
LS
I
+61
303
and
LS
5039
at
high
energies
with
the
Fermi
Large
Area
Telescope
(LAT)
and
the
first
discovery
of
superorbital
variability
at
high
energies
from
the
source
LS
I
+61
303.
Gamma-‐ray
binaries
are
stellar
systems
for
which
the
spectral
energy
distribution
(discounting
the
thermal
stellar
emission)
peaks
at
high
energies.
Detected
from
radio
to
TeV
gamma
rays,
the
gamma-‐ray
binary
LS
I
+61
303
is
highly
variable
across
all
frequencies.
One
aspect
of
this
system's
variability
is
the
modulation
of
its
emission
with
the
timescale
set
by
the
26.496-‐day
orbital
period.
In
this
thesis
we
show
for
the
first
time
that
the
gamma-‐ray
emission
of
LS
I
+61
303
also
presents
a
sinusoidal
variability
at
the
known
superorbital
period
of
1667
days.
This
modulation
is
more
prominently
seen
at
orbital
phases
around
apastron,
whereas
it
does
not
introduce
a
visible
change
close
to
periastron.
It
is
also
found
in
the
appearance
and
disappearance
of
variability
at
the
orbital
period
in
the
power
spectrum
of
the
data.
This
behavior
could
be
explained
by
a
quasi-‐cyclical
evolution
of
the
equatorial
outflow
of
the
Be
companion
star,
whose
features
influence
the
conditions
for
generating
gamma
rays.
These
findings
open
for
the
first
time
the
possibility
to
use
gamma-‐ray
observations
to
study
the
outflows
of
massive
stars
in
eccentric
binary
systems.
2. Study
of
the
gamma-ray
emission
of
magnetars
at
high
and
very
high
energies
with
the
LAT
and
the
MAGIC
Cherenkov
telescopes.
Magnetars
are
a
peculiar
class
of
neutron
stars
showing
emission
from
radio
up
to
some
hundreds
of
keV.
They
can
be
characterized
through
their
bursting
behavior
and
through
an
energy
loss
rate,
which
is
too
small
to
power
their
X-‐ray
luminosity.
Therefore,
it
is
believed
that
the
X-‐ray
emission
of
the
neutron
star
is
powered
by
the
decay
and
the
instabilities
of
their
strong
magnetic
field.
In
this
thesis,
these
objects
are
studied
for
the
first
time
at
high
and
very
high
energies
with
the
LAT
and
the
MAGIC
telescopes.
We
put
the
first
constraints
on
their
emission
in
this
high
energy
regime.
Furthermore,
this
strong
observational
diagnostic
forces
a
revision
of
the
parameter
space
applicable
for
the
viability
of
the
outer
gap
model
of
Cheng
&
Zhang
(2001)
and
Zhang
&
Cheng
(2002)
to
each
magnetar.
3. Prospects
for
the
Cherenkov
astronomy
with
the
future
Cherenkov
Telescope
Array
(CTA).
The
next
generation
of
Imaging
Air
Cherenkov
Telescopes
will
be
CTA.
This
experiment
is
nowadays
in
the
design
phase.
In
this
thesis
we
evaluate
the
potentialities
of
CTA
to
study
the
non-‐thermal
physics
of
gamma-‐ray
binaries,
which
requires
the
observation
of
high-‐energy
phenomena
at
different
time
and
spatial
scales.
To
do
so
we
study
gamma-‐ray
binaries
in
the
context
of
the
known
or
expected
physics
of
these
sources.
CTA
will
be
able
to
probe
with
high
spectral,
temporal
and
spatial
resolution
the
physical
processes
behind
the
gamma-‐ray
emission
in
binaries,
significantly
increasing
as
well
the
number
of
known
sources.
We
found
that
the
sensitivity
of
CTA
will
lead
to
a
very
good
sampling
of
light
curves
and
spectra
on
very
short
timescales.
It
will
allow
as
well
long
source
monitoring
using
subarrays,
still
with
a
sensitivity
2–3
times
better
than
any
previous
instrument
operating
at
VHE
energies.
In
particular,
it
is
noteworthy
that
CTA
will
reduce
by
a
factor
of
a
few
the
errors
in
the
determination
of
fluxes
and
spectral
indexes
On the binary nature of the γ-ray sources AGL J2241+4454 (= MWC 656) and HESS J0632+057 (= MWC 148)
No full textWe present optical spectroscopy of MWC 656 and MWC 148, the proposed optical counterparts of the gamma-ray sources AGL J2241+4454 and HESS J0632+0 57, respectively. The main parameters of the Halpha emission line (EW, FWHM and centroid velocity) in these stars are modulated on the proposed orbital periods of 60.37 and 321 days, respectively. These modulations are likely produced by the resonant interaction of the Be discs with compact stars in eccentric orbits. We also present radial velocity curves of the optical stars folded on the above periods and obtain the first orbital elements of the two gamma-ray sources thus confirming their binary nature. Our orbital solution support eccentricities e~0.4 and 0.83+-0.08 for MWC 656 and MWC 148, respectively. Further, our orbital elements imply that the X-ray outbursts in HESS J0632+057/MWC 148 are delayed ~0.3 orbital phases after periastron passage, similarly to the case of LS I +61 303. In addition, the optical photometric light curve maxima in AGL J2241+4454/MWC 656 occur ~0.25 phases passed periastron, similar to what is seen in LS I +61 303. We also find that the orbital eccentricity is correlated with orbital period for the known gamma-ray binaries. This is explained by the fact that small stellar separations are required for the efficient triggering of VHE radiation. Another correlation between the EW of Halpha and orbital period is also observed, similarly to the case of Be/X-ray binaries. These correlations are useful to provide estimates of the key orbital parameters Porb and e from the Halpha line in future Be gamma-ray binary candidates
Trobat l'accelerador de partícules en la radiogalàxia Messier 87
No full textUn equip internacional d'investigadors, dirigit per l'Institut de Física d'Altes Energies (IFAE), adscrit a la UAB, i de l'Institut Max Planck, ha descobert la localització exacta de la regió d'acceleració de partícules en la veïna radiogalàxia gegant Messier 87.Un equipo internacional de investigadores, dirigido por el Instituto de Física de Altas Energías (IFAE), adscrito a la UAB y del Instituto Max Planck, ha descubierto la localización exacta de la región de aceleración de partículas en la vecina radiogaláxia gigante Messier 87, un núcleo galáctico activo situado a unos 55 millones de años luz de la Tierra
Discovery of very high energy gamma-ray emission from the blazar 1ES 1727+502 with the MAGIC Telescopes
No full textAleksic, J. et al.-- Full list of authors: Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Backes, M.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnefoy, S.; Bonnoli, G.; Borla Tridon, D.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Carreto Fidalgo, D.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Caneva, G.; de Lotto, B.; Delgado Mendez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Eisenacher, D.; Elsaesser, D.; Farina, E.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giavitto, G.; Godinović, N.; González Muñoz, A.; Gozzini, S. R.; Hadamek, A.; Hadasch, D.; Häfner, D.; Herrero, A.; Hose, J.; Hrupec, D.; Idec, W.; Jankowski, F.; Kadenius, V.; Klepser, S.; Knoetig, M. L.; Krähenbühl, T.; Krause, J.; Kushida, J.; La Barbera, A.; Lelas, D.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Masbou, J.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Nakajima, D.; Niedzwiecki, A.; Nilsson, K.; Nowak, N.; Orito, R.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Partini, S.; Persic, M.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamatescu, V.; Stamerra, A.; Steinke, B.; Storz, J.; Sun, S.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zandanel, F.; Zanin, R.; MAGIC CollaborationMotivated by the prediction of a high TeV luminosity we investigated whether the blazar 1ES 1727+502 (z = 0.055) is emitting very high energy (VHE, E > 100 GeV) γ rays. We observed the BL Lac object 1ES 1727+502 in stereoscopic mode with the two MAGIC telescopes for 14 nights between May 6th and June 10th 2011, for a total effective observing time of 12.6 h. To study the multiwavelength spectral energy distribution (SED), we used simultaneous optical R-band data from the KVA telescope, archival UV/optical and X-ray observations from instruments UVOT and XRT on board of the Swift satellite, and high energy (HE, 0.1 GeV–100 GeV) γ-ray data from the Fermi-LAT instrument. We detected, for the first time, VHE γ-ray emission from 1ES 1727+502 at a statistical significance of 5.5σ. The integral flux above 150 GeV is estimated to be (2.1 ± 0.4)% of the Crab nebula flux and the de-absorbed VHE spectrum has a photon index of (2.7 ± 0.5). No significant short-term variability was found in any of the wavebands presented here. We model the SED using a one-zone synchrotron self-Compton model obtaining parameters typical for this class of sources. © ESO 2014We would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is gratefully acknowledged. This work was also supported by the CPAN CSD2007-00042 and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, by grant DO02-353 of the Bulgarian NSF, by grant 127740 of the Academy of Finland, by the DFG Cluster of Excellence “Origin and Structure of the Universe”, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, and by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0. The Fermi-LAT Collaboration acknowledges support from a number of agencies and institutes for both development and the operation of the LAT as well as scientific data analysis. These include NASA and DOE in the United States, CEA/Irfu and IN2P3/CNRS in France, ASI and INFN in Italy, MEXT, KEK, and JAXA in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the National Space Board in Sweden. Additional support from INAF in Italy and CNES in France for science analysis during the operations phase is also gratefully acknowledged.Peer reviewe
Search for very high energy gamma-rays from the z = 0.896 quasar 4C +55.17 with the MAGIC telescopes
No full textAleksic, J. et al.-- Full list of authors: Aleksić, J.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Carreto Fidalgo, D.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Lotto, B.; Delgado Mendez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher, D.; Elsaesser, D.; Farina, E.; Ferenc, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giavitto, G.; Godinović, N.; González Muñoz, A.; Gozzini, S. R.; Hadasch, D.; Hayashida, M.; Herrero, A.; Hildebrand, D.; Hose, J.; Hrupec, D.; Idec, W.; Kadenius, V.; Kellermann, H.; Knoetig, M. L.; Kodani, K.; Konno, Y.; Krause, J.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Munar-Adrover, P.; Nakajima, D.; Niedzwiecki, A.; Nilsson, K.; Nishijima, K.; Nowak, N.; Orito, R.; Overkemping, A.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Partini, S.; Persic, M.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Preziuso, S.; Puljak, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Garcia, J. Rodriguez; Rügamer, S.; Saggion, A.; Saito, T.; Saito, K.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Stamatescu, V.; Stamerra, A.; Steinbring, T.; Storz, J.; Sun, S.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Vogler, P.; Wagner, R. M.; Zandanel, F.; Zanin, R.The bright gamma-ray quasar 4C +55.17 is a distant source (z = 0.896) with a hard spectrum at GeV energies as observed by the Large Area Telescope (LAT) on board the Fermi satellite. This source is identified as a good source candidate for very high energy (VHE; >30 GeV) gamma-rays. In general, VHE gamma-rays from distant sources provide a unique opportunity to study the extragalactic background light (EBL) and underlying astrophysics. The flux intensity of this source in the VHE range is investigated. Then, constraints on the EBL are derived from the attenuation of gamma-ray photons coming from the distant blazar. We searched for a gamma-ray signal from this object using the 35 h observations taken by the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes between 2010 November and 2011 January. No significant VHE gamma-ray signal was detected. We computed the upper limits of the integrated gamma-ray flux at the 95 per cent confidence level of 9.4 × 10-12 and 2.5 × 10-12 cm-2 s-1 above 100 and 200 GeV, respectively. The differential upper limits in four energy bins in the range from 80 to 500 GeV are also derived. The upper limits are consistent with the attenuation predicted by low-flux EBL models on the assumption of a simple power-law spectrum extrapolated from LAT data. © 2014 The AuthorsWe would like to thank the Instituto de Astrof´ısica de Canarias for
the excellent working conditions at the Observatorio del Roque de
los Muchachos in La Palma. The support of the German BMBF
and MPG, the Italian INFN, the Swiss National Fund SNF and the
Spanish MICINN is gratefully acknowledged. This work was also
supported by the CPAN CSD2007-00042 and MultiDark CSD2009-
00064 projects of the Spanish Consolider-Ingenio 2010 programme,
by grant 127740 of the Academy of Finland, by the DFG Cluster
of Excellence ‘Origin and Structure of the Universe’, by the DFG
Collaborative Research Centers SFB823/C4 and SFB876/C3, and
by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0.Peer reviewe
Observations of the magnetars 4U0142+61 and 1E2259+586 with the MAGIC telescopes:(Research Note)
No full textFull list of authors: Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; Bretz, T.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Cea del Pozo, E.; De Lotto, B.; Delgado Mendez, C.; Diago Ortega, A.; Doert, M.; Dominis Prester, D.; Dorner, D.; Doro, M.; Eisenacher, D.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giavitto, G.; Godinović, N.; González Muñoz, A.; Gozzini, S. R.; Hadamek, A.; Hadasch, D.; Häfner, D.; Herrero, A.; Hose, J.; Hrupec, D.; Huber, B.; Jankowski, F.; Jogler, T.; Kadenius, V.; Klepser, S.; Knoetig, M. L.; Krähenbühl, T.; Krause, J.; Kushida, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Niedzwiecki, A.; Nieto, D.; Nilsson, K.; Nowak, N.; Orito, R.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Partini, S.; Persic, M.; Pilia, M.; Pochon, J.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamatescu, V.; Stamerra, A.; Steinke, B.; Storz, J.; Sun, S.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.; Rea, N.; Backes, MContext. Magnetars are an extreme, highly magnetized class of isolated neutron stars whose large X-ray luminosity is believed to be driven by their high magnetic field. Aims. We study for the first time the possible very high energy γ-ray emission above 100GeV from magnetars, observing the sources 4U0142+61 and 1E2259+586. Methods. We observed the two sources with atmospheric Cherenkov telescopes in the very high energy range (E> 100GeV). 4U0142+61 was observed with the MAGICA I telescope in 2008 for about 25h and 1E2259+586 was observed with the MAGIC stereoscopic system in 2010 for about 14h. The data were analyzed with the standard MAGIC analysis software. Results. Neither magnetar was detected. Upper limits to the differential and integral flux above 200GeV were computed using the Rolke algorithm. We obtain integral upper limits to the flux of 1.52 × 10-12cm-2s-1 and 2.7 × 10-12 cm-2s-1 with a confidence level of 95% for 4U0142+61 and 1E2259+586, respectively. The resulting differential upper limits are presented together with X-ray data and upper limits in the GeV energy range. © 2012 ESO.We would like to thank the Instituto de Astrofísica de
Canarias for the excellent working conditions at the Observatorio del Roque
de los Muchachos in La Palma. The support of the German BMBF and MPG,
the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is
gratefully acknowledged. This work was also supported by the CPAN CSD2007-
00042 and MultiDark CSD2009-00064 projects of the Spanish Consolider-
Ingenio 2010 programme, by grant DO02-353 of the Bulgarian NSF, by grant
127740 of the Academy of Finland, by the DFG Cluster of Excellence “Origin
and Structure of the Universe”, by the DFG Collaborative Research Centers
SFB823/C4 and SFB876/C3, and by the Polish MNiSzW grant 745/N-HESS-
MAGIC/2010/0.Peer reviewe
Contemporaneous observations of the radio galaxy NGC 1275 from radio to very high energy γ-rays
No full textAleksic, J. et al.-- Full list of authors: Aleksić, J.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Carreto Fidalgo, D.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Lotto, B.; Delgado Mendez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher, D.; Elsaesser, D.; Farina, E.; Ferenc, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giavitto, G.; Godinović, N.; González Muñoz, A.; Gozzini, S. R.; Hadamek, A.; Hadasch, D.; Herrero, A.; Hildebrand, D.; Hose, J.; Hrupec, D.; Idec, W.; Kadenius, V.; Kellermann, H.; Knoetig, M. L.; Krause, J.; Kushida, J.; La Barbera, A.; Lelas, D.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Munar-Adrover, P.; Nakajima, D.; Niedzwiecki, A.; Nilsson, K.; Nowak, N.; Orito, R.; Overkemping, A.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Partini, S.; Persic, M.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Preziuso, S.; Puljak, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rodriguez Garcia, J.; Rügamer, S.; Saggion, A.; Saito, T.; Saito, K.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Stamatescu, V.; Stamerra, A.; Steinbring, T.; Storz, J.; Sun, S.; Surić, T.; Takalo, L.; Tavecchio, F.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Zandanel, F.; Zanin, R.; MAGIC Collaboration; Balmaverde, B.; Kataoka, J.; Rekola, R.; Takahashi, Y.Aims. The radio galaxy NGC 1275, recently identified as a very high energy (VHE, >100 GeV) γ-ray emitter by MAGIC, is one of the few non-blazar active galactic nuclei detected in the VHE regime. The purpose of this work is to better understand the origin of the γ-ray emission and locate it within the galaxy.Methods. We studied contemporaneous multifrequency observations of NGC 1275 and modeled the overall spectral energy distribution. We analyzed unpublished MAGIC observations carried out between October 2009 and February 2010, and the previously published observations taken between August 2010 and February 2011. We studied the multiband variability and correlations by analyzing data of Fermi-LAT in the 100 MeV–100 GeV energy band, as well as Chandra (X-ray), KVA (optical), and MOJAVE (radio) data taken during the same period.Results. Using customized Monte Carlo simulations corresponding to early MAGIC stereoscopic data, we detect NGC 1275 also in the earlier MAGIC campaign. The flux level and energy spectra are similar to the results of the second campaign. The monthly light curve above 100 GeV shows a hint of variability at the 3.6σ level. In the Fermi-LAT band, both flux and spectral shape variabilities are reported. The optical light curve is also variable and shows a clear correlation with the γ-ray flux above 100 MeV. In radio, three compact components are resolved in the innermost part of the jet. One of these components shows a similar trend as the Fermi-LAT and KVA light curves. The γ-ray spectra measured simultaneously with MAGIC and Fermi-LAT from 100 MeV to 650 GeV can be well fitted either by a log-parabola or by a power-law with a subexponential cutoff for the two observation campaigns. A single-zone synchrotron-self-Compton model, with an electron spectrum following a power-law with an exponential cutoff, can explain the broadband spectral energy distribution and the multifrequency behavior of the source. However, this model suggests an untypical low bulk-Lorentz factor or a velocity alignment closer to the line of sight than the parsec-scale radio jet. © ESO 2014The MAGIC collaboration would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is gratefully acknowledged. This work was also supported by the CPAN CSD2007-00042 and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, by grant DO02-353 of the Bulgarian NSF, by grant 127740 of the Academy of Finland, by the DFG Cluster of Excellence “Origin and Structure of the Universe”, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, and by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0. The Fermi-LAT Collaboration acknowledges ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Énergie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This research has made use of data from the MOJAVE database that is maintained by the MOJAVE team (Lister et al. 2009).Peer reviewe
MAGIC upper limits on the GRB 090102 afterglow
No full textAleksic, J. et al.-- Full list of authors: Aleksić, J.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Carreto Fidalgo, D.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Lotto, B.; Delgado Mendez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Eisenacher, D.; Elsaesser, D.; Farina, E.; Ferenc, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giavitto, G.; Godinović, N.; González Munoz, A.; Gozzini, S. R.; Hadamek, A.; Hadasch, D.; Herrero, A.; Hose, J.; Hrupec, D.; Idec, W.; Kadenius, V.; Knoetig, M. L.; Krähenbühl, T.; Krause, J.; Kushida, J.; La Barbera, A.; Lelas, D.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López-Coto, R.; López, M.; López-Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Masbou, J.; Mazin, D.; Menzel, U.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Nakajima, D.; Niedzwiecki, A.; Nilsson, K.; Nowak, N.; Orito, R.; Overkemping, A.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Partini, S.; Persic, M.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Preziuso, S.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Garcia, J. Rodriguez; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Stamatescu, V.; Stamerra, A.; Storz, J.; Sun, S.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zandanel, F.; Zanin, R.; Bouvier, A.; Hayashida, M.; Tajima, H.; Longo, F.Indications of a GeV component in the emission from gamma-ray bursts (GRBs) are known since the Energetic Gamma-Ray Experiment Telescope observations during the 1990s and they have been confirmed by the data of the Fermi satellite. These results have, however, shown that our understanding of GRB physics is still unsatisfactory. The new generation of Cherenkov observatories and in particular the MAGIC telescope, allow for the first time the possibility to extend the measurement of GRBs from several tens up to hundreds of GeV energy range. Both leptonic and hadronic processes have been suggested to explain the possible GeV/TeV counterpart of GRBs. Observations with ground-based telescopes of very high energy (VHE) photons (E > 30 GeV) from these sources are going to play a key role in discriminating among the different proposed emission mechanisms, which are barely distinguishable at lower energies. MAGIC telescope observations of the GRB 090102 (z = 1.547) field and Fermi Large Area Telescope data in the same time interval are analysed to derive upper limits of the GeV/TeV emission. We compare these results to the expected emissions evaluated for different processes in the framework of a relativistic blastwave model for the afterglow. Simultaneous upper limits with Fermi and a Cherenkov telescope have been derived for this GRB observation. The results we obtained are compatible with the expected emission although the difficulties in predicting the HE and VHE emission for the afterglow of this event makes it difficult to draw firmer conclusions. Nonetheless, MAGIC sensitivity in the energy range of overlap with space-based instruments (above about 40 GeV) is about one order of magnitude better with respect to Fermi. This makes evident the constraining power of ground-based observations and shows that the MAGIC telescope has reached the required performance to make possible GRB multiwavelength studies in the VHE range. © 2013 The AuthorsWe acknowledge an anonymous referee for useful comments.
We would like to thank the Instituto de Astrof´ısica de Canarias
for the excellent working conditions at the Observatorio del Roque
de los Muchachos in La Palma. The support of the German BMBF
and MPG, the Italian INFN, the Swiss National Fund SNF and the
Spanish MICINN is gratefully acknowledged. This work was also
supported by the CPAN CSD2007-00042 and MultiDark CSD2009-
00064 projects of the Spanish Consolider-Ingenio 2010 programme,
by grant DO02-353 of the Bulgarian NSF, by grant 127740 of the
Academy of Finland, by the DFG Cluster of Excellence ‘Origin
and Structure of the Universe’, by the DFG Collaborative Research
Centers SFB823/C4 and SFB876/C3 and by the Polish MNiSzW
grant 745/N-HESS-MAGIC/2010/0.
The Fermi-LAT Collaboration acknowledges support from a
number of agencies and institutes for both development and the operation of the LAT as well as scientific data analysis. These include
NASA and DOE in the United States; CEA/Irfu and IN2P3/CNRS
in France; ASI and INFN in Italy; MEXT, KEK and JAXA in Japan;
and the K. A. Wallenberg Foundation, the Swedish Research Council and the National Space Board in Sweden. Additional support
from INAF in Italy and CNES in France for science analysis during
the operations phase is also gratefully acknowledged. This research
is partially supported by NASA through the Fermi Guest Investigator Grants NNX09AT92G and NNX10AP22G. This work made
use of data supplied by the UK Swift Science Data Centre at the
University of Leicester.Peer reviewe
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