52 research outputs found
Molecular Cloning and Rare Cleavage Mapping of Human 2P, 6Q, 8Q, 12Q, and 18Q Telomeres
Large terminal fragments of human chromosomes 2p, 6q, 8q, 12q, and 18q were cloned using yeast artificial chromosomes (YACs). RecA-assisted restriction endonuclease (RARE) cleavage analysis of genomic DNA samples from 11 unrelated individuals using YAC-derived probes confirmed the telomeric localizations of the half-YACs studied. The cloned Fragments provide telomeric closure of maps for the respective chromosome arms and will supply the reagents needed for analyzing and sequencing these distal subtelomeric regions
MAXI GSC observations of a spectral state transition in the black hole candidate XTE J1752-223
We present the first results on the black hole candidate XTE J1752-223 from
the Gas Slit Camera (GSC) on-board the Monitor of All-sky X-ray Image (MAXI) on
the International Space Station. Including the onset of the outburst reported
by the Proportional Counter Array on-board the Rossi X-ray Timing Explorer on
2009 October 23, the MAXI/GSC has been monitoring this source approximately 10
times per day with a high sensitivity in the 2-20 keV band. XTE J1752-223 was
initially in the low/hard state during the first 3 months. An anti-correlated
behavior between the 2-4 keV and 4-20 keV bands were observed around January
20, 2010, indicating that the source exhibited the spectral transition to the
high/soft state. A transient radio jet may have been ejected when the source
was in the intermediate state where the spectrum was roughly explained by a
power-law with a photon index of 2.5-3.0. The unusually long period in the
initial low/hard state implies a slow variation in the mass accretion rate, and
the dramatic soft X-ray increase may be explained by a sudden appearance of the
accretion disk component with a relatively low innermost temperature (0.4-0.7
keV). Such a low temperature might suggest that the maximum accretion rate was
just above the critical gas evaporation rate required for the state transition.Comment: Publication of Astronomical Society of Japan Vol.62, No.5 (2010) [in
print
The MAXI Mission on the ISS: Science and Instruments for Monitoring All Sky X-Ray Images
The MAXI (Monitor of All-sky X-ray Image) mission is the first astronomical
payload to be installed on the Japanese Experiment Module-Exposed Facility
(JEM-EF) on the ISS. It is scheduled for launch in the middle of 2009 to
monitor all-sky X-ray objects on every ISS orbit. MAXI will be more powerful
than any previous X-ray All Sky Monitor (ASM) payloads, being able to monitor
hundreds of AGN. MAXI will provide all sky images of X-ray sources of about 20
mCrab in the energy band of 2-30 keV from observation on one ISS orbit (90
min), about 4.5 mCrab for one day, and about 1 mCrab for one month. A final
detectability of MAXI could be 0.2 mCrab for 2 year observations.Comment: 12 pages, 11 figures, accepted for publication in Publications of the
Astronomical Society of Japa
A Spectral Study of the Black Hole Candidate XTE J1752-223 in the High/Soft State with MAXI, Suzaku and Swift
We report on the X-ray spectral analysis of the black hole candidate XTE\
J1752--223 in the 2009--2010 outburst, utilizing data obtained with the
MAXI/Gas Slit Camera (GSC), the Swift/XRT, and Suzaku, which work
complementarily. As already reported by Nakahira et al. (2010) MAXI monitored
the source continuously throughout the entire outburst for about eight months.
All the MAXI/GSC energy spectra in the high/soft state lasting for 2 months are
well represented by a multi-color disk plus power-law model. The innermost disk
temperature changed from 0.7 keV to 0.4 keV and the disk flux
decreased by an order of magnitude. Nevertheless, the innermost radius is
constant at 41 km, where is the
source distance in units of 3.5 kpc and the inclination. The multi-color
disk parameters obtained with the MAXI/GSC are consistent with those with the
Swift/XRT and Suzaku. The Suzaku data also suggests a possibility that the disk
emission is slightly Comptonized, which could account for broad iron-K features
reported previously. Assuming that the obtained innermost radius represents the
innermost stable circular orbit for a non-rotating black hole, we estimate the
mass of the black hole to be 5.510.28 , where the correction for the stress-free inner boundary condition
and color hardening factor of 1.7 are taken into account. If the inclination is
less than 49 as suggested from the radio monitoring of transient jets
and the soft-to-hard transition in 2010 April occurred at 1--4% of Eddignton
luminosity, the fitting of the Suzaku spectra with a relativistic
accretion-disk model derives constraints on the mass and the distance to be
3.1--55 and 2.3--22 {\rm kpc}, respectively. This confirms that the
compact object in XTE J1752--223 is a black hole.Comment: 12 pages including 7 figures and 4 tables, accepted for publication
in PAS
A Large X-ray Flare from a Single Weak-lined T Tauri Star TWA-7 Detected with MAXI GSC
We present a large X-ray flare from a nearby weak-lined T Tauri star TWA-7
detected with the Gas Slit Camera (GSC) on the Monitor of All-sky X-ray Image
(MAXI). The GSC captured X-ray flaring from TWA-7 with a flux of
ergs cm s in 2--20 keV band during the scan
transit starting at UT 2010-09-07 18:24:30.The estimated X-ray luminosity at
the scan in the energy band is 3 ergs s,indicating that
the event is among the largest X-ray flares fromT Tauri stars.Since MAXI GSC
monitors a target only during a scan transit of about a minute per 92 min
orbital cycle, the luminosity at the flare peak might have been higher than
that detected. At the scan transit, we observed a high X-ray-to-bolometric
luminosity ratio, log = ; i.e., the
X-ray luminosity is comparable to the bolometric luminosity. Since TWA-7 has
neither an accreting disk nor a binary companion, the observed event implies
that none of those are essential to generate such big flares in T Tauri stars.Comment: 4 pages, 2 figures, 1 table accepted for publication in PAS
Topical Treatment for Orbital Capillary Hemangioma in an Adult Using a β-Blocker Solution
Purpose: To report a case of orbital capillary hemangioma in an adult who was successfully treated with topical timolol maleate 0.5% solution. Methods: Case report. Results: A 43-year-old female presented both superficial and deep orbital capillary hemangioma. Topical timolol maleate was applied twice daily. The superficial lesions have nearly disappeared after 1 year of treatment. The deeper lesions have also been reduced in size according to MRI. Conclusion: We report an adult patient with a relatively large orbital capillary hemangioma who was successfully treated with a topical β-blocker solution. This treatment might be applicable for orbital capillary hemangiomas, regardless of the patient's age, because of its effectiveness and safety
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