103 research outputs found
Chandra Observation of the Anomalous X-ray Pulsar 1E 1841-045
We present the results from the {\it Chandra} ACIS CC mode observation of an
anomalous X-ray pulsar (AXP) 1E 1841-045. This is the first observation in
which the pulsar spectrum in wide energy range is spatially discriminated from
the surrounding SNR, Kes 73. Like other AXPs, the phase-integrated spectrum is
fitted well with power-law plus blackbody model. The spectral parameters are
, keV, and . This photon index is
significantly flatter than the other AXPs, and resemble to soft gamma-ray
repeaters (SGRs) in the quiescent state. The pulse profile is double-peaked,
and we found that the second peak has significantly hard spectrum. The spectra
of all phases are consistent with power-law plus blackbody model with constant
temperature and photon index. When fitted with two blackbody model, we obtained
similarly good fit. These results can be interpreted that there are two
emission regions with different energy spectra.Comment: 4 pages, 4 figures, accepted for publication in PASJ Letter
Pulse Profile Change Possibly Associated with a Glitch in an Anomalous X-Ray Pulsar 4U 0142+61
We report a glitch-like pulse frequency deviation from the simple spin-down
law in an anomalous X-ray pulsar (AXP) 4U 0142+61 detected by ASCA
observations. We also found a significant pulse profile change after the
putative glitch. The glitch parameters resemble those found in another AXP 1RXS
J170849.0400910, in the Vela pulsar, and in other radio pulsars. This
suggests that the radio pulsars and AXPs have the same internal structure and
glitch mechanism. It must be noted, however, that the pulse frequency anomaly
can also be explained by a gradual change of the spin-down rate ()
without invoking a glitch.Comment: 14 pages, 4 figures, accepted by Ap
重症足潰瘍に対する皮膚灌流圧による評価
広島大学(Hiroshima University)博士(医学)Doctor of Philosophy in Medical Sciencedoctora
Search for Near-Infrared Pulsation of the Anomalous X-ray Pulsar 4U 0142+61
We have searched for pulsation of the anomalous X-ray pulsar (AXP) 4U 0142+61
in the K' band ( m) using the fast-readout mode
of IRCS at the Subaru 8.2-m telescope. We found no significant signal at the
pulse frequency expected by the precise ephemeris obtained by the X-ray
monitoring observation with RXTE. Nonetheless, we obtained a best upper limit
of 17% (90% C.L.) for the root-mean-square pulse fraction in the K' band.
Combined with i' band pulsation (Dhillon et al. 2005), the slope of the pulsed
component () was constrained to (90%
C.L.) for an interstellar extinction of .Comment: 11 pages, 3 figures, Accepted for publication in PAS
Comportamento dos especuladores no boom e no crach do mercado de derivativos
Orientador: Fernando Nogueira da CostaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de EconomiaResumo: Não informadoAbstract: Not informed.MestradoMestre em Ciências Econômica
Suzaku Observation of the Anomalous X-ray Pulsar 1E 1841-045
We report the results of a Suzaku observation of the anomalous X-ray pulsar
(AXP) 1E 1841-045 at a center of the supernova remnant Kes 73. We confirmed
that the energy-dependent spectral models obtained by the previous separate
observations were also satisfied over a wide energy range from 0.4 to ~70 keV,
simultaneously. Here, the models below ~10 keV were a combination of blackbody
(BB) and power-law (PL) functions or of two BBs wit h different temperatures at
0.6 - 7.0 keV (Morii et al. 2003), and that above ~20 keV was a PL function
(Kuiper Hermsen Mendez 2004). The combination BB + PL + PL was found to best
represent the phase-averaged spectrum. Phase-resolved spectroscopy indicated
the existence of two emission regions, one with a thermal and the other with a
non-thermal nature. The combination BB + BB + PL was also found to represent
the phase-averaged spectrum well. However, we found that this model is
physically unacceptable due to an excessively large area of the emission region
of the blackbody. Nonetheless, we found that the temperatures and radii of the
two blackbody components showed moderate correlations in the phase-resolved
spectra. The fact that the same correlations have been observed between the
phase-averaged spectra of various magnetars (Nakagawa et al. 2009) suggests
that a self-similar function can approximate the intrinsic energy spectra of
magnetars below ~10 keV.Comment: Accepted for publication in the PAS
Direct Method for Determination of Valproic Acid in Serum by High Performance Liquid Chromatography.
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