We present the third MAXI/GSC catalog in the high Galactic-latitude sky (\(|b| > 10^\circ\)) based on the 7-year data from 2009 August 13 to 2016 July 31, complementary to that in the low ...Galactic-latitude sky (\(|b| < 10^\circ\); Hori et al. 2018). We compile 682 sources detected at significances of \(s_{\rm D,4-10~keV} \geq 6.5\) in the 4--10 keV band. A two-dimensional image fit based on the Poisson likelihood algorithm (\(C\)-statistics) is adopted for the detections and constraints on their fluxes and positions. The 4--10 keV sensitivity reaches \(\approx 0.48\) mCrab, or \(\approx 5.9 \times 10^{-12}\) erg cm\(^{-2}\) s\(^{-1}\), over the half of the survey area. Compared with the 37-month catalog (Hiroi et al. 2013), which adopted a threshold of \(s_{\rm D,4-10~keV} \geq 7\), the source number increases by a factor of \(\sim\)1.4. The fluxes in the 3--4 keV and 10--20 keV bands are further estimated, and hardness ratios (HRs) are calculated using the 3--4 keV, 4--10 keV, 3--10 keV, and 10--20 keV band fluxes. We also make the 4--10 keV lightcurves in one year bins for all the sources and characterize their variabilities with an index based on a likelihood function and the excess variance. Possible counterparts are found from five major X-ray survey catalogs by Swift, Uhuru, RXTE, XMM-Newton, and ROSAT, and an X-ray galaxy-cluster catalog (MCXC). Our catalog provides the fluxes, positions, detection significances, HRs, one-year bin lightcurves, variability indices, and counterpart candidates.
Multi-wavelength observations of the black-widow binary system 2FGL J2339.6-0532 are reported. The Fermi gamma-ray source 2FGL J2339.6-0532 was recently categorized as a black widow in which a ...recycled millisecond pulsar (MSP) is evaporating up the companion star with its powerful pulsar wind. Our optical observations show clear sinusoidal light curves due to the asymmetric temperature distribution of the companion star. Assuming a simple geometry, we constrained the range of the inclination angle of the binary system to 52\(^{\circ}\) < i < 59\(^{\circ}\), which enables us to discuss the interaction between the pulsar wind and the companion in detail. The X-ray spectrum consists of two components: a soft, steady component that seems to originate from the surface of the MSP, and a hard variable component from the wind-termination shock near the companion star. The measured X-ray luminosity is comparable to the bolometric luminosity of the companion, meaning that the heating efficiency is less than 0.5. In the companion orbit, 10\(^{11}\) cm from the pulsar, the pulsar wind is already in particle dominant-stage, with a magnetization parameter of \(\sigma\) < 0.1. In addition, we precisely investigated the time variations of the X-ray periodograms and detected a weakening of orbital modulation. The observed phenomenon may be related to an unstable pulsar-wind activity or a weak mass accretion, both of which can result in the temporal extinction of radio-pulse.
Monitor of all-sky image (MAXI) Gas Slit Camera (GSC) detects gamma-ray bursts (GRBs) including the bursts with soft spectra, such as X-ray flashes (XRFs). MAXI/GSC is sensitive to the energy range ...from 2 to 30 keV. This energy range is lower than other currently operating instruments which is capable of detecting GRBs. Since the beginning of the MAXI operation on August 15, 2009, GSC observed 35 GRBs up to the middle of 2013. One third of them are also observed by other satellites. The rest of them show a trend to have soft spectra and low fluxes. Because of the contribution of those XRFs, the MAXI GRB rate is about three times higher than those expected from the BATSE log N - log P distribution. When we compare it to the observational results of the Wide-field X-ray Monitor on the High Energy Transient Explorer 2, which covers the the same energy range to that of MAXI/GSC, we find a possibility that many of MAXI bursts are XRFs with Epeak lower than 20 keV. We discuss the source of soft GRBs observed only by MAXI. The MAXI log N - log S distribution suggests that the MAXI XRFs distribute in closer distance than hard GRBs. Since the distributions of the hardness of galactic stellar flares and X-ray bursts overlap with those of MAXI GRBs, we discuss a possibility of a confusion of those galactic transients with the MAXI GRB samples.
The Kiso Supernova Survey (KISS) is a high-cadence optical wide-field supernova (SN) survey. The primary goal of the survey is to catch the very early light of a SN, during the shock breakout phase. ...Detection of SN shock breakouts combined with multi-band photometry obtained with other facilities would provide detailed physical information on the progenitor stars of SNe. The survey is performed using a 2.2x2.2 deg field-of-view instrument on the 1.05-m Kiso Schmidt telescope, the Kiso Wide Field Camera (KWFC). We take a three-minute exposure in g-band once every hour in our survey, reaching magnitude g~20-21. About 100 nights of telescope time per year have been spent on the survey since April 2012. The number of the shock breakout detections is estimated to be of order of 1 during our 3-year project. This paper summarizes the KISS project including the KWFC observing setup, the survey strategy, the data reduction system, and CBET-reported SNe discovered so far by KISS.
We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey (KISS). The source brightened in the optical by at least a factor of ...three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z=0.840, however with unusually strong narrow emission lines. The estimated black hole mass of ~ 10^7 Msun implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R ~ 4 x 10^2 - 3 x 10^3, which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and gamma-ray loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxies.
A total of 905 enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates that were recovered from experimentally infected cattle, in addition to the inoculated strain, were analyzed by pulsed-field ...gel electrophoresis (PFGE). Twelve PFGE profiles other than that of the inoculated strain were observed. We successfully identified five distinct chromosomal deletions that affected the PFGE profiles using whole-genome PCR scanning and DNA sequencing analysis. The changes in PFGE profiles of EHEC O157:H7 isolates after passage through the intestinal tract of cattle were partially generated by deletion of chromosomal regions.
Therapeutic efficacy and the treatment days for cure of imipenem/cilastatin sodium (IPM/CS) in treatmentof pulmonary infections were prospectively determined in comparison with those of β-lactams ...other thancarbapenems mainly ceftazidime (CAZ) or sulbactam/cefoperazone (SBT/CPZ). The overall response rate was 84.9% (62/73) in the IPM/CS group and 74.7% (56/75) in the β-lactam group, the difference not being significant. In the subjects having underlying respiratory diseases, the response rate was91.1% (41/45) and 73.9% (34/46) in the IPM/CS and β-lactam groups, respectively. In patients with infectionssecondary to chronic respiratory disease, the rate was 91.2% (31/34) in the former group and 66.7% (24/36) inthe latter group, respectively. The differences were significant for both stratified analyses.The treatment days for cure judged by the attending physician were 12.9±0.6 days in the IPM/CS group, and 14.5±0.7 days in the β-lactam group. The difference was not, however, significant. In patients with mild tomoderate infections, the treatment days for cure was 12.0±0.6 days (n=64) in the IPM/CS group and 14.3±0.7days (n=70) in the β-lactam group. In patients with underlying respiratory disease, the treatment days for curewere 11.8±0.7 days (n=45) and 14.7±0.9 days (n=46) in the IPM/CS and β-lactam groups, respectively. In patientswith infections secondary to chronic respiratory disease, the days were 11.1±0.7 days (n=34) and14.7±1.1 days (n=36), respectively. Thus, IPM/CS therapy significantly reduced the number of treatment daysuntil cure. There was, however, no significant difference between the two therapy groups in treatment of the patientswith severe infections, those without underlying respiratory disease, or those with pneumonia and/or lungabscess. The treatment days for cure were also assessed by the members of review committee taking into considerationof body temperature, leukocyte count, and C-reactive protein. As the result, it was 6.9±0.5 days in the IPM/CS and 10.3±0.7 days in the β-lactam groups, respectively, and the difference was significant. Time (days) untilcure was also compared between the two groups using survival time analysis, confirming a more rapid responsein the IPM/CS group. Although IPM/CS therapy was associated with a shorter response time as assessed by boththe attending physicians and the review committee, there were considerable differences between the results ofthese judgements. Thus, the duration of treatment with injectable antibiotics requires reevaluation in the future. No significant differences were observed between the groups with respect to parameters indicating side effectsand laboratory abnormalities. There were no severe symptoms or laboratory findings, and symptoms andchanges in laboratory values, if any resolved during the course of therapy or after the withdrawal of treatment. In conclusion, IPM/CS seems to be very useful as first-line therapy for respiratory tract infections and for shortening the duration of treatment.
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