31 research outputs found
INTEGRAL observations of V0332+53 in outburst
We present the analysis of a 100ksec Integral(3-100kev) observation of the
transient X-ray pulsar V0332+53 inoutburst. The source is pulsating at
P=4.3751+/-0.0002s with a clear double pulse from 6 kev to 60 kev. The average
flux was ~550mCrab between 20 kev and 60 kev. We modeled the broad band
continuum from 5 kev to 100 kev with a power-law modified by an exponential cut
off. We observe three cyclotron lines: the fundamental line at 24.9+/-0.1 kev,
the first harmonic at 50.5+/-0.1 kev as well as the second harmonic
at71.7+/-0.8 kev, thus confirming the discovery of the harmonic lines by Coburn
et al. (2005) in RXTE data.Comment: 4 pages, 3 figures. Accepted for publication in A&A Letter
Alpha-decay properties of superheavy elements in the relativistic mean-field theory with vector self-coupling of meson
We have investigated properties of -decay chains of recently produced
superheavy elements Z=115 and Z=113 using the new Lagrangian model NL-SV1 with
inclusion of the vector self-coupling of meson in the framework of the
relativistic mean-field theory. It is shown that the experimentally observed
alpha-decay energies and half-lives are reproduced well by this Lagrangian
model. Further calculations for the heavier elements with Z=117-125 show that
these nuclei are superdeformed with a prolate shape in the ground state. A
superdeformed shell-closure at Z=118 lends an additional binding and an extra
stability to nuclei in this region. Consequently, it is predicted that the
corresponding values provide -decay half-lives for heavier
superheavy nuclei within the experimentally feasible conditions. The results
are compared with those of macroscopic-microscopic approaches. A perspective of
the difference in shell effects amongst various approaches is presented and its
consequences on superheavy nuclei are discussed.Comment: Revised version, 14 pages, 12 eps figures. To appear in PRC.
Discussion on shell effects is shortened in the revised version. However,
commonality of the role of shell effects in extreme superheavy regions and in
the regions near the r-process path is maintained. Existence of a secondary
superdeformed minimum for Z=113 is verified with another Lagrangian se
An active state of the BL Lac Object Markarian 421 detected by INTEGRAL in April 2013
Multiwavelength variability of blazars offers indirect insight into their
powerful engines and on the mechanisms through which energy is propagated from
the centre down the jet. The BL Lac object Mkn 421 is a TeV emitter, a bright
blazar at all wavelengths, and therefore an excellent target for variability
studies. Mkn 421 was observed by INTEGRAL and Fermi-LAT in an active state on
16-21 April 2013. Well sampled optical, soft, and hard X-ray light curves show
the presence of two flares. The average flux in the 20-100 keV range is 9.1e-11
erg/s/cm2 (~4.5 mCrab) and the nuclear average apparent magnitude, corrected
for Galactic extinction, is V ~12.2. In the time-resolved X-ray spectra (3.5-60
keV), which are described by broken power laws and, marginally better, by
log-parabolic laws, we see a hardening that correlates with flux increase, as
expected in refreshed energy injections in a population of electrons that later
cool via synchrotron radiation. The hardness ratios between the JEM-X fluxes in
two different bands and between the JEM-X and IBIS/ISGRI fluxes confirm this
trend. During the observation, the variability level increases monotonically
from the optical to the hard X-rays, while the large LAT errors do not allow a
significant assessment of the MeV-GeV variability. The cross-correlation
analysis during the onset of the most prominent flare suggests a monotonically
increasing delay of the lower frequency emission with respect to that at higher
frequency, with a maximum time-lag of about 70 minutes, that is however not
well constrained. The spectral energy distributions from the optical to the TeV
domain are satisfactorily described by homogeneous models of blazar emission
based on synchrotron radiation and synchrotron self-Compton scattering, except
in the state corresponding to the LAT softest spectrum and highest flux.Comment: 11 pages, 6 figures, in press in A&
INTEGRAL and Swift/XRT observations on IGR J18179-1621
IGR J18179-1621 is a hard X-ray binary transient discovered recently by
INTEGRAL. Here we report on detailed timing and spectral analysis on IGR
J18179-1621 in X-rays based on available INTEGRAL and Swift data. From the
INTEGRAL analysis, IGR J18179-1621 is detected with a significance of 21.6
sigma in the 18-40 keV band by ISGRI and 15.3 sigma in the 3-25 keV band by
JEM-X, between 2012-02-29 and 2012-03-01. We analyze two quasisimultaneous
Swift ToO observations. A clear 11.82 seconds pulsation is detected above the
white noise at a confidence level larger than 99.99%. The pulse fraction is
estimated as 22+/-8% in 0.2-10 keV. No sign of pulsation is detected by
INTEGRAL/ISGRI in the 18-40 keV band. With Swift and INTEGRAL spectra combined
in soft and hard X-rays, IGR J18179-1621 could be fitted by an absorbed power
law with a high energy cutoff plus a Gaussian absorption line centered at 21.5
keV. An additional absorption intrinsic to the source is found, while the
absorption line is evidence for most probably originated from cyclotron
resonant scattering and suggests a magnetic field in the emitting region of
\sim 2.4 \times 10^12 Gauss.Comment: 5 pages, 3 figures, 1 table; accepted to MNRAS Letter
INTEGRAL/IBIS nine-year Galactic Hard X-Ray Survey
Context. The INTEGRAL observatory operating in a hard X-ray/gamma domain has
gathered a large observational data set over nine years starting in 2003. Most
of the observing time was dedicated to the Galactic source population study,
making possible the deepest Galactic survey in hard X-rays ever compiled. Aims.
We aim to perform a Galactic survey that can be used as the basis of Galactic
source population studies, and perform mapping of the Milky Way in hard X-rays
over the maximum exposure available at |b|<17.5 deg. Methods. We used sky
reconstruction algorithms especially developed for the high quality imaging of
INTEGRAL/IBIS data. Results. We present sky images, sensitivity maps, and
catalogs of detected sources in the three energy bands 17-60, 17-35, and 35-80
keV in the Galactic plane at |b|<17.5 deg. The total number of sources in the
reference 17-60 keV band includes 402 objects exceeding a 4.7 sigma detection
threshold on the nine-year time-averaged map. Among the identified sources with
known and tentatively identified natures, 253 are Galactic objects (108
low-mass X-ray binaries, 82 high-mass X-ray binaries, 36 cataclysmic variables,
and 27 are of other types), and 115 are extragalactic objects, including 112
active galactic nuclei (AGNs) and 3 galaxy clusters. The sample of Galactic
sources with S/N>4.7 sigma has an identification completeness of ~92%, which is
valuable for population studies. Since the survey is based on the nine-year sky
maps, it is optimized for persistent sources and may be biased against finding
transients.Comment: 18 pages, 7 figures, long table, Astronomy and Astrophysics 545, A2
Fusion reaction 48Ca+249Bk leading to formation of the element Ts (Z=117)
The heaviest currently known nuclei, which have up to 118 protons, have been produced in 48Ca induced reactions with actinide targets. Among them, the element tennessine (Ts), which has 117 protons, has been synthesized by fusing 48Ca with the radioactive target 249Bk, which has a half-life of 327 d. The experiment was performed at the gas-filled recoil separator TASCA. Two long and two short α decay chains were observed. The long chains were attributed to the decay of 294Ts. The possible origin of the short-decay chains is discussed in comparison with the known experimental data. They are found to fit with the decay chain patterns attributed to 293Ts. The present experimental results confirm the previous findings at the Dubna Gas-Filled Recoil Separator on the decay chains originating from the nuclei assigned to Ts
Pharmacological inhibition of p38MAPK in macrophages ameliorates ischemia reperfusion injury after small bowel transplantation (SBTx)
Major Esophageal Dilation After Laparoscopic Adjustable Gastric Banding in Symptomatic Patients : Does It Prevent Effective Weight Loss and How Should It be Treated?
Operations and Data Processing for the Planck Low-Frequency Instrument: Design Strategies and Practical Experience
23Planck is an ESA mission launched in May 2009, which is mapping the microwave sky in nine frequencies and accurately measuring the anisotropies of the Cosmic Microwave Background (CMB) with its complement of two instruments (HFI and LFI), covering respectively the far infrared and the radio domains. The operations and data processing of the Planck instruments are carried out by Data Processing Centers, one for each instrument. The DPCs need to support both a day-by-day quasi-real-time calibration workflow and high-throughput pipelines for a high-volume data flow. The LFI DPC has been designed to be a centralized facility built by geographically distributed institutions, in a funding scenario based on multiple funding agencies and, in most cases, on a fixed budget in the presence of launch delays. A strategy for managing effectively the distributed and collaborative software development and maintenance has been developed, based on the use of open source and off-the-shelf software, and on the reuse of systems developed ad-hoc for other missions. Product and quality assurance has been supported throughout development, integration and testing. The effectiveness of the design choices has been proven by the readiness of the system at launch time and by the extremely smooth operations phase.Planck is an ESA mission launched in May 2009, which is mapping the microwave sky in nine frequencies and accurately measuring the anisotropies of the Cosmic Microwave Background (CMB) with its complement of two instruments (HFI and LFI), covering respectively the far infrared and the radio domains. The operations and data processing of the Planck instruments are carried out by Data Processing Centers, one for each instrument. The DPCs need to support both a day-by-day quasi-real-time calibration workflow and high-throughput pipelines for a high-volume data flow.nonemixedPasian, F.; Zacchei, A.; Frailis, M.; Galeotta, S.; Maris, M.; Tavagnacco, D.; Vuerli, C.; Tuerler, M.; Rohlfs, R.; Morisset, N.; Meharga, M.; Ensslin, T. A.; Knoche, J.; Gregorio, A.; Maino, D.; Mennella, A.; Tomasi, M.; Cuttaia, F.; Morgante, G.; Terenzi, L.; Maggio, G.; Gasparo, F.; Franceschi, E.Pasian, F.; Zacchei, A.; Frailis, M.; Galeotta, S.; Maris, M.; Tavagnacco, Daniele; Vuerli, C.; Tuerler, M.; Rohlfs, R.; Morisset, N.; Meharga, M.; Ensslin, T. A.; Knoche, J.; Gregorio, Anna; Maino, D.; Mennella, A.; Tomasi, M.; Cuttaia, F.; Morgante, G.; Terenzi, L.; Maggio, G.; Gasparo, F.; Franceschi, E