2,621 research outputs found
Swift Observations of the Be/X-ray Transient System 1A 1118-615
We report results of Swift observations for the high mass Be/X-ray binary
system 1A 1118-615, during an outburst stage in January, 2009 and at a flaring
stage in March, 2009. Using the epoch-folding method, we successfully detected
a pulsed period of 407.69(2) sec in the outburst of January and of 407.26(1)
sec after the flare detection in March. We find that the spectral detection for
the source during outburst can be described by a blackbody model with a high
temperature (kT ~ 1-3 keV) and a small radius (R ~ 1 km), indicating that the
emission results from the polar cap of the neutron star. On the other hand, the
spectra obtained after the outburst can further be described by adding an
additional component with a lower temperature (kT ~ 0.1-0.2 keV) and a larger
emission radius (R ~ 10-500 km), which indicates the emission from around the
inner region of an accretion disk. We find that the thermal emission from the
hot spot of the accreting neutron star dominates the radiation in outburst; the
existence of both this X-ray contribution and the additional soft component
suggest that the polar cap and the accretion disk emission might co-exist after
the outburst. Because the two-blackbody signature at the flaring stage is a
unique feature of 1A 1118-615, our spectral results may provide a new insight
to interpret the X-ray emission for the accreting neutron star. The time
separation between the three main outbursts of this system is ~17 years and it
might be related to the orbital period. We derive and discuss the associated
physical properties by assuming the elongated orbit for this specific Be/X-ray
transient.Comment: 9 pages, 3 figures and 4 tables; accepted by MNRA
Development of a Piezoelectric Vacuum Sensing Component for a Wide Pressure Range
In this study, we develop a clamped-clamped beam-type piezoelectric vacuum pressure sensing element. The clamped-clamped piezoelectric beam is composed of a PZT layer and a copper substrate. A pair of electrodes is set near each end. An input voltage is applied to a pair of electrodes to vibrate the piezoelectric beam, and the output voltage is measured at the other pair. Because the viscous forces on the piezoelectric beam vary at different air pressures, the vibration of the beam depends on the vacuum pressure. The developed pressure sensor can sense a wide range of pressure, from 6.5 × 10(-6) to 760 Torr. The experimental results showed that the output voltage is inversely proportional to the gas damping ratio, and thus, the vacuum pressure was estimated from the output voltage
Mean-variance model with fuzzy random data
This paper recommends discourse feeling acknowledgment from discourse signal dependent on highlights examination and PNN-classifier. The arrangement of acknowledgment incorporates discovery of discourse feelings, extraction and determination of highlights, lastly characterization. These highlights are valued to segregate the greatest number of tests precisely and the PNN classifier dependent on discriminant investigation is utilized to characterize the six distinctive articulations. The reproduced outcomes will be indicated that the channel occupied component extortion with utilized distribution presents much better exactness with less algorithmic unpredictability than other discourse feeling articulation acknowledgment draws near
Influence of migration policy risk on international market segmentation: analysis of housing and rental markets in the euro area
This paper aims to discuss the influence of migration policy risk
on market segmentation of housing and rental markets in the
Euro Area. Policy risk is represented by the Migration Policy
Uncertainty Index (MPUI) and Migration Fear Index (MFI) of
Germany and the United Kingdom; in this study, whether these
indexes influence the interaction between the housing and rental
markets of the two countries and euro-area countries was examined.
The empirical results showed that the influence of the
United Kingdom’s migration policy risk on the euro-area countries
is higher than that of Germany. The United Kingdom’s MPUI and
MFI significantly contribute to the influence of the United
Kingdom’s housing market on other markets except for Belgium
and Spain. Compared with housing market connectedness, the
rental market connectedness is less influenced by migration policy
risk and migration fear. This may be because variables related
to short-term residence policies influence the rental market. The
high policy risk is more likely to influence decisions related to
long-term house purchase, but not those related to short-term
residence. Finally, this study found that the higher the uncertainty
of the migration policies of the United Kingdom and Germany is,
the higher the house market segmentation is
The X-ray Properties of the Energetic Pulsar PSR J1838-0655
We present and interpret several new X-ray features of the X-ray pulsar PSR
J1838-0655. The X-ray data are obtained from the archival data of CHANDRA,
RXTE}, and SUZAKU. We combine all these X-ray data and fit the spectra with
different models. We find that the joint spectra are difficult to fit with a
single power law; a broken power-law model with a break at around 6.5 keV can
improve the fit significantly. The photon index changes from = 1.0
(below 6.5 keV) to = 1.5 (above 6.5 keV); this indicates a softer
spectral behaviour at hard X-rays. The X-ray flux at 2-20 keV is found to be
1.6x10^{-11} ergs cm^{-2} s^{-1}. The conversion efficiency from the spin-down
luminosity is ~ 0.9% at 0.8-10 keV, which is much higher than that (~ 10^{-3}%
- 10^{-4}%) of the pulsars that show similar timing properties. We discuss
non-thermal radiation mechanisms for the observed high X-ray conversion
efficiency and find that emission from the magnetosphere of a greatly inclined
rotator is the most favorable interpretation for the conversion rate and the
pulse profiles at X-ray bands. A line feature close to 6.65 keV is also
detected in the spectra of SUZAKU/XIS; it might be the K emission of
highly ionised Fe surrounding the pulsar.Comment: 8 pages, 6 figures and 1 tabl
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