318 research outputs found
A search for cyclotron resonance features with INTEGRAL
We present an INTEGRAL observation of the Cen-Crux region in order to search
the electron cyclotron resonance scattering features from the X-ray binary
pulsars. During the AO1 200ks observation, we clearly detected 4 bright X-ray
binaries, 1 Seyfert Galaxy, and 4 new sources in the field of view. Especially
from GX301-2, the cyclotron resonance feature is detected at about 37 keV, and
width of 3--4 keV. In addition, the depth of the resonance feature strongly
depends on the X-ray luminosity. This is the first detection of luminosity
dependence of the resonance depth. The cyclotron resonance feature is
marginally detected from 1E1145.1-6141. Cen X-3 was very dim during the
observation and poor statistics disable us to detect the resonance
features.These are first INTEGRAL results of searching for the cyclotron
resonance feature.Comment: 4pages, 8figures, To be published in the Proceedings of the 5th
INTEGRAL Workshop: "The INTEGRAL Universe", February 16-20, 2004, Munic
Relações entre a intensidade e duração das atividades em partida de basquetebol com as capacidades aeróbica e anaeróbica: estudo pelo lactato sangüíneo
Os esportes com bola se caracterizam pela alternância de períodos de atividades de curta duração e alta intensidade intercalados com períodos de recuperação. Neste tipo de exercício, o metabolismo anaeróbico é considerado predominante, porém, o seu grau de solicitação depende da distribuição dessas atividades ao longo da partida. Com o propósito de caracterizar o perfil da atividade e a relação com o metabolismo predominante em partida, jogadores de uma equipe de basquetebol foram submetidos a teste de campo para avaliação do condicionamento anaeróbico (5 x 30 m em velocidade máxima com 1 minuto de pausa) e aeróbico (limiar de lactato, 4 mM em 3 x 1200 m progressivos). Em três partidas foram determinados o lactato sangüíneo, e através de videotape, a distribuição da duração de atividades de alta e baixa intensidade. Durante as partidas o lactato sangüíneo atingiu valores de 2,68 — 1,30 mM, e foi significativamente correlacionado (p < 0,05) com a duração das atividades de baixa intensidade e longa duração (superior a 3") (63,4 — 3,5 %, r = -0,451), alta intensidade e curta duração (inferior a 3”) (11,2 - 1,4 %, r = 0,477) e alta intensidade e longa duração (10,4 —1,1 %, r = 0,900). Houve correlação significativa também entre o lactato médio em partida com o tempo médio (4,28 — 0,24 s, r = -0,758) e lactato (5,15 - 1,42 mM, r = 0,645) nos tiros de 30 m. Esses resultados indicam que durante a partida de basquetebol há predominância do metabolismo anaeróbico alático e que nos períodos de interrupção do jogo, há possibilidade de remoção do lactato circulanteThe ball games represent intermittent work with frequent interchange of short bursts of physcial effort interspaced with pauses. For this reason they are generally considered anaerobic type activities. However, the extent of anaerobic yield is highly correlated with the effort:relief ratio pattern. The present study was designed in order to investigate the metabolic profile of basketball game, particullary the extent of the anaerobic metabolism, and its relation with the intensity of the activities during a game and the aerobic and anaerobic condition of the player. Basketball players (n =14) were evaluated in a set of field test consisted with: a) anaerobic capacity, 5 x 30 m at maximal running speed, with 1 min rest and b) aerobic capacity expressed as a anaerobic threshold (blood lactate = 4 mM 3 x 1200 m graded field test). Three games were videotaped and the duration of high and low intensity activities were determined. Additionally blood samples were obtained at the end of the game for lactate analysis (YSL 2300, Yellow Spring Co, USA). The blood lactate during the games (2.68 — 1.30 mM) was significantly correlated with the duration of the long term (more than 3 s) low intensity activities (63.4 - 3.5 %, r = - 0.451), the short term (less than 3 s) high intensity activities (11.2 — 1.4 %, r = 0.477) and long term high intensity activities (10.4 — 1.1 %, r = 0.900). Significant correlations were also found between the game blood lactate and the mean running time (4.28 -1 0.24 s, r = - 0.758) and blood lactate (5.15 — 1.42 mM, r = 0.645) in the 30 m dashes. These findings showed that the anaerobic alatacid metabolism is the main energy source for the basketball game. Additionally, the blood lactate are removed during the light activities which interspace the high intensity bursts of effort
XMM-Newton and Suzaku detection of an X-ray emitting shell around the pulsar wind nebula G54.1+0.3
Recent X-ray observations have proved to be very effective in detecting
previously unknown supernova remnant shells around pulsar wind nebulae (PWNe),
and in these cases the characteristics of the shell provide further clues on
the evolutionary stage of the embedded PWN. However, it is not clear why some
PWNe are still "naked". We carried out an X-ray observational campaign targeted
at the PWN G54.1+0.3, the "close cousin" of the Crab, with the aim to detect
the associated SNR shell. We analyzed an XMM-Newton and Suzaku observations of
G54.1+0.3 and we model out the contribution of dust scattering halo. We
detected an intrinsic faint diffuse X-ray emission surrounding a hard spectrum,
which can be modeled either with a power-law (gamma= 2.9) or with a thermal
plasma model (kT=2.0 keV.). If the shell is thermal, we derive an explosion
energy E=0.5-1.6x10^51 erg, a pre-shock ISM density of 0.2 cm^-3 and an age of
about 2000 yr. Using these results in the MHD model of PWN-SNR evolution, we
obtain an excellent agreement between the predicted and observed location of
the shell and PWN shock.Comment: Accepted for publication in A&A, 8 pages, 5 figures, full-res version
at http://www.astropa.inaf.it/Library/OAPA_preprints/h14298.pd
Resonant Inelastic X-Ray Scattering at the K Edge of Ge
We study the resonant inelastic x-ray scattering (RIXS) at the edge of
Ge. We measure RIXS spectra with systematically varying momenta in the final
state. The spectra are a measure of exciting an electron-hole pair. We find a
single peak structure (except the elastic peak) as a function of photon energy,
which is nearly independent of final-state momenta. We analyze the experimental
data by means of the band structure calculation. The calculation reproduces
well the experimental shape, clarifying the implication of the spectral shape.Comment: 17 pages,9 figures, Please also see our related paper:
cond-mat/040500
Suzaku Observation of Two Ultraluminous X-Ray Sources in NGC 1313
Two ultraluminous X-ray sources (ULXs) in the nearby Sb galaxy NGC 1313,
named X-1 and X-2, were observed with Suzaku on 2005 September 15. During the
observation for a net exposure of 28~ks (but over a gross time span of 90~ks),
both objects varied in intensity by about 50~%. The 0.4--10 keV X-ray
luminosity of X-1 and X-2 was measured as
and , respectively, with the former the
highest ever reported for this ULX. The spectrum of X-1 can be explained by a
sum of a strong and variable power-law component with a high energy cutoff, and
a stable multicolor blackbody with an innermost disk temperature of
keV. These results suggest that X-1 was in a ``very high'' state, where the
disk emission is strongly Comptonized. The absorber within NGC 1313 toward X-1
is suggested to have a subsolar oxygen abundance. The spectrum of X-2 is best
represented, in its fainter phase, by a multicolor blackbody model with the
innermost disk temperature of 1.2--1.3 keV, and becomes flatter as the source
becomes brighter. Hence X-2 is interpreted to be in a slim-disk state. These
results suggest that the two ULXs have black hole masses of a few tens to a few
hundreds solar masses.Comment: accepted for publication in PAS
Suzaku Observations of Ejecta-Dominated Galactic Supernova Remnant G346.6-0.2
We present here the results of the X-ray analysis of Galactic supernova
remnant G346.6-0.2 observed with {\it Suzaku}. K-shell emission lines of Mg,
Si, S, Ca and Fe are detected clearly for the first time. Strong emission lines
of Si and S imply that X-ray emission nature of G346.6-0.2 is ejecta-dominated.
The ejecta-dominated emission is well fitted with a combined model consisting
of thermal plasma in non-equilibrium ionization and a non-thermal component,
which can be regarded as synchrotron emission with a photon index of
. Absorbing column density of is obtained from the best-fitting implying a high-density medium,
high electron temperature of keV, and ionization timescale
of indicating that this
remnant may be far from full ionization equilibrium. The relative abundances
from the ejecta show that the remnant originates from a Type Ia supernova
explosion.Comment: 7 pages, 4 figur
Prospect of Studying Hard X- and Gamma-Rays from Type Ia Supernovae
We perform multi-dimensional, time-dependent radiation transfer simulations
for hard X-ray and gamma-ray emissions, following radioactive decays of 56Ni
and 56Co, for two-dimensional delayed detonation models of Type Ia supernovae
(SNe Ia). The synthetic spectra and light curves are compared with the
sensitivities of current and future observatories for an exposure time of 10^6
seconds. The non-detection of the gamma-ray signal from SN 2011fe at 6.4 Mpc by
SPI on board INTEGRAL places an upper limit for the mass of 56Ni of \lesssim
1.0 Msun, independently from observations in any other wavelengths. Signals
from the newly formed radioactive species have not been convincingly measured
yet from any SN Ia, but the future X-ray and gamma-ray missions are expected to
deepen the observable horizon to provide the high energy emission data for a
significant SN Ia sample. We predict that the hard X-ray detectors on board
NuStar (launched in 2012) or ASTRO-H (scheduled for launch in 2014) will reach
to SNe Ia at \sim15 Mpc, i.e., one SN every few years. Furthermore, according
to the present results, the soft gamma-ray detector on board ASTRO-H will be
able to detect the 158 keV line emission up to \sim25 Mpc, i.e., a few SNe Ia
per year. Proposed next generation gamma-ray missions, e.g., GRIPS, could reach
to SNe Ia at \sim20 - 35 Mpc by MeV observations. Those would provide new
diagnostics and strong constraints on explosion models, detecting rather
directly the main energy source of supernova light.Comment: 14 pages, 7 figures, 1 table, accepted for publication in Ap
The Suzaku view of 3C 382
We present a long Suzaku observation of 3C 382. A Swift BAT spectrum from the
58-month survey is also analyzed, together with an archival XMM-Newton EPIC
exposure. Our main result is the finding with Suzaku of a broad FeK line with a
relativistic profile consistent with emission from an accretion disk at tens of
gravitational radii from the central black hole. The XIS data indicate emission
from highly ionized iron and allow us to set tight, albeit model-dependent,
constraints on the inner and outer radii of the disk reflecting region,
r_in~10r_g and r_out~20r_g, respectively, and on the disk inclination, i~30deg.
Two ionized reflection components are possibly observed, with similar
contributions of ~10% to the total continuum. A highly ionized one, with
log_xi~3, which successfully models the relativistic line and a mildly ionized
one, with log_xi~1.5, which models the narrow Fe K line and high energy hump.
When both these components are included, there is no further requirement for an
additional black body soft excess below 2keV. The Suzaku data confirm the
presence of a warm absorber previously known from grating studies. After
accounting for all the spectral features, the intrinsic photon index of the
X-ray continuum is ~1.8 with a cutoff energy at ~200keV, consistent with
Comptonization models and excluding jet-related emission up to these energies.
Comparison of the X-ray properties of 3C 382 and other BLRGs to Seyferts
confirms the idea that the distinction between radio-loud and radio-quiet AGN
at X-rays is blurred.Comment: Accepted for publication in Ap
Construction of Special Solutions for Nonintegrable Systems
The Painleve test is very useful to construct not only the Laurent series
solutions of systems of nonlinear ordinary differential equations but also the
elliptic and trigonometric ones. The standard methods for constructing the
elliptic solutions consist of two independent steps: transformation of a
nonlinear polynomial differential equation into a nonlinear algebraic system
and a search for solutions of the obtained system. It has been demonstrated by
the example of the generalized Henon-Heiles system that the use of the Laurent
series solutions of the initial differential equation assists to solve the
obtained algebraic system. This procedure has been automatized and generalized
on some type of multivalued solutions. To find solutions of the initial
differential equation in the form of the Laurent or Puiseux series we use the
Painleve test. This test can also assist to solve the inverse problem: to find
the form of a polynomial potential, which corresponds to the required type of
solutions. We consider the five-dimensional gravitational model with a scalar
field to demonstrate this.Comment: LaTeX, 14 pages, the paper has been published in the Journal of
Nonlinear Mathematical Physics (http://www.sm.luth.se/math/JNMP/
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