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DISCOVERY OF AN X-RAY-EMITTING CONTACT BINARY SYSTEM 2MASS J11201034−2201340
Hu, Chin-Ping,Yang, Ting-Chang,Chou, Yi,Liu, L.,Qian, S.-B.,Hui, C. Y.,Kong, Albert K. H.,Lin, L. C. C.,Tam, P. H. T.,Li, K. L.,Ngeow, Chow-Choong,Chen, W. P.,Ip, Wing-Huen American Astronomical Society 2016 The Astronomical journal Vol.151 No.6
<P>We report the detection of orbital modulation, a model solution, and the X-ray properties of a newly discovered contact binary, Two Micron All Sky Survey (2MASS) J11201034-2201340. We serendipitously found this X-ray point source outside the error ellipse when searching for possible X-ray counterparts of 7-ray millisecond pulsars among the unidentified objects detected by the Fermi Gamma-ray Space Telescope. The optical counterpart of the X-ray source (unrelated to the 7-ray source) was then identified using archival databases. The long-term Catalina Real-Time Transient Survey detected a precise signal with a period of P = 0.28876208 (56) days. A follow-up observation made by the Super Light Telescope of Lulin Observatory revealed the binary nature of the object. Utilizing archived photometric data of multi-band surveys, we construct the spectral energy distribution (SED), which is well fit by a K2V spectral template. The fitting result of the orbital profile using the Wilson Devinney code suggests that 2MASS J11201034-2201340 is a short-period A-type contact binary and the more massive component has a cool spot. The X-ray emission was first noted in observations made by Swift, and then further confirmed and characterized by an XMM-Newton observation. The X-ray spectrum can be described by a power law or thermal Bremsstrahlung. Unfortunately, we could not observe significant X-ray orbital modulation. Finally, according to the SED, this system is estimated to be 690 pc from Earth with a calculated X-ray intensity of (0.7 - 1.5) x 10(30) erg s(-1), which is in the expected range of an X-ray emitting contact binary.</P>
APPLICATIONS OF THE HILBERT-HUANG TRANSFORM ON THE NON-STATIONARY ASTRONOMICAL TIME SERIES
HU, CHIN-PING,CHOU, YI,YANG, TING-CHANG,SU, YI-HAO,HSIEH, HUNG-EN,LIN, CHING-PING,CHUANG, PO-SHENG,LIAO, NAI-HUI The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2
The development of time-frequency analysis techniques allow astronomers to successfully deal with the non-stationary time series that originate from unstable physical mechanisms. We applied a recently developed time-frequency analysis method, the Hilbert-Huang transform (HHT), to two non-stationary phenomena: the superorbital modulation in the high-mass X-ray binary SMC X-1 and the quasi-periodic oscillation (QPO) of the AGN RE J1034+396. From the analysis of SMC X-1, we obtained a Hilbert spectrum that shows more detailed information in both the time and frequency domains. Then, a phase-resolved analysis of both the spectra and the orbital profiles was presented. From the spectral analysis, we noticed that the iron line production is dominated by different regions of this binary system in different superorbital phases. Furthermore, a pre-eclipse dip lying at orbital phase ~0:6-0:85 was discovered during the superorbital transition state. We further applied the HHT to analyze the QPO of RE J1034+396. From the Hilbert spectrum and the O-C analysis results, we suggest that it is better to divide the evolution of the QPO into three epochs according to their different periodicities. The correlations between the QPO periods and corresponding fluxes were also different in these three epochs. The change in periodicity and the relationships could be interpreted as the change in oscillation mode based on the diskoseismology model.
ON THE COMPLEX VARIABILITY OF THE SUPERORBITAL MODULATION PERIOD OF LMC X-4
HU, CHIN-PING,LIN, CHING-PING,CHOU, YI,YANG, TING-CHANG,SU, YI-HAO,HSIEH, HUNG-EN,CHUANG, PO-SHENG,LIAO, NAI-HUI The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2
LMC X-4 is an eclipsing high-mass X-ray binary exhibiting a superorbital modulation with a period of ~ 30:5 days. We present a detailed study of the variations of the superorbital modulation period with a time baseline of ~ 18 years. The period determined in the light curve collected by the Monitor of All-sky X-ray Image (MAXI) significantly deviates from that observed by the All Sky Monitor (ASM) onboard the Rossi X-ray Timing Explorer (RXTE). Using the data collected by RXTE/ASM, MAXI, and the Burst Alert Telescope (BAT) onboard Swift, we found a significant period derivative, $\dot{P}=(2.08{\pm}0.12){\times}10^{-5}$. Furthermore, the O{C residual shows complex short-term variations indicating that the superorbital modulation of LMC X-4 exhibits complicated unstable behaviors. In addition, we used archive data collected by the Proportional Counter Array (PCA) on RXTE to estimate the orbital and spin parameters. The detected pulse frequencies obtained in small time segments were fitted with a circular orbital Doppler shift model. In addition to orbital parameters and spin frequency for each observation, we found a spin frequency derivative of $\dot{v}=(6.482{\pm}0.011){\times}10^{-13}Hz{\cdot}s^{-1}$. More precise orbital and spin parameters will be evaluated by the pulse arrival time delay technique in the future.
Fa-Po Chung,Chin-Yu Lin,Yenn-Jiang Lin,Shih-Lin Chang,Li-Wei Lo,Yu-Feng Hu,Ta-Chuan Tuan,Tze-Fan Chao,Jo-Nan Liao,Ting-Yung Chang,Shih-Ann Chen 대한심장학회 2018 Korean Circulation Journal Vol.48 No.10
Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is predominantly an inherited cardiomyopathy with typical histopathological characteristics of fibro-fatty infiltration mainly involving the right ventricular (RV) inflow tract, RV outflow tract, and RV apex in the majority of patients. The above pathologic evolution frequently brings patients with ARVD/C to medical attention owing to the manifestation of syncope, sudden cardiac death (SCD), ventricular arrhythmogenesis, or heart failure. To prevent future or recurrent SCD, an implantable cardiac defibrillator (ICD) is highly desirable in patients with ARVD/C who had experienced unexplained syncope, hemodynamically intolerable ventricular tachycardia (VT), ventricular fibrillation, and/or aborted SCD. Notably, the management of frequent ventricular tachyarrhythmias in ARVD/C is challenging, and the use of antiarrhythmic drugs could be unsatisfactory or limited by the unfavorable side effects. Therefore, radiofrequency catheter ablation (RFCA) has been implemented to treat the drug-refractory VT in ARVD/C for decades. However, the initial understanding of the link between fibro-fatty pathogenesis and ventricular arrhythmogenesis in ARVD/C is scarce, the efficacy and prognosis of endocardial RFCA alone were limited and disappointing. The electrophysiologists had broken through this frontier after better illustration of epicardial substrates and broadly application of epicardial approaches in ARVD/C. In recent works of literature, the application of epicardial ablation also successfully results in higher procedural success and decreases VT recurrences in patients with ARVD/C who are refractory to the endocardial approach during long-term follow-up. In this article, we review the important evolution on the delineation of arrhythmogenic substrates, ablation strategies, and ablation outcome of VT in patients with ARVD/C.
Event-Triggered Media Stream Bandwidth Adjustment in IoT-Based Home Networks
Chao-Yu Hsu,Chin-Lin Hu,Kun-Sheng Huang,Yung-Hui Chen,Jiun-Long Huang 한국통신학회 2020 한국통신학회 APNOMS Vol.2020 No.09
As the coming maturity of Internet of Things, many home-networked devices with various sensors are deployed in residential environments. It is important to accommodate many devices that compete for bandwidth allocation to transmit data inwards and outwards through a certain home network domain. This paper proposes a novel mechanism which can adjust media stream qualities and transmission bandwidth allocations to different devices. This mechanism is agile against dynamic changes of data workload and finite network resources between inside and outside of a home network. Practical demonstration exhibits that the effects are able to maintain differentiated media transfer services in IoT-based home networks.
THE ORBITAL EPHEMERIS OF THE PARTIAL ECLIPSING X-ray BINARY X1822-371
HSIEH, HUNG-EN,CHOU, YI,HU, CHIN-PING,YANG, TING-CHANG,SU, YI-HAO,LIN, CHING-PING,CHUANG, PO-SHENG,LIAO, NAI-HUI The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2
X1822-371 is a low mass X-ray binary with an accretion disk corona exhibiting partial eclipses and pulsations in the X-ray band. We update its orbital ephemeris by combining new RXTE observations and historical records, with a total time span of 34 years. There were 11 RXTE observations in 2011 but the eclipsing profile can be seen in only 4 of them. The eclipsing center times were obtained by fitting the profile with the same model as previous studies. Combined with the eclipsing center times reported by Iaria et al. (2011), the O-C analysis was processed. A quadratic model was applied to fit the O-C results and produced a mean orbital period derivative of $\dot{P}_{orb}=1.339(25){\times}10^{-10}s/s$, which is slightly smaller than previous records. In addition to the orbital modulation from the orbital profile, we also present our preliminary results for measuring the orbital parameters using the orbital Doppler effect from the pulsation of the neutron star in X1822-371. The updated orbital parameters from eclipsing profiles will be further compared with the ones from pulsar timing.
THE UPDATED ORBITAL PERIOD OF LOW MASS X-ray BINARY 4U 1323-62
CHUANG, PO-SHENG,CHOU, YI,HU, CHIN-PING,YANG, TING-CHANG,SU, YI-HAO,LIAO, NAI-HUI,HSIEH, HUNG-EN,LIN, CHING-PING The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2
4U 1323-62, a low mass X-ray binary with an orbital period of 2.94 hr, exhibits periodic X-ray dips, which are due to absorption by the bulge of the outer accretion disk. The purpose of this study is to search for orbital period changes using archived X-ray data over a time span of 20 years. We present our preliminary results from analyzing light curves observed by RXTE, BeppoSAX, XMM-Newton and Suzaku. We used the method proposed by Hu et al. (2008) to estimate dip center time and adopted the Observed - Calculated method to measure changes in period. We obtained an orbital period of 2.941917(36) hr and a period derivative of $\dot{P}_{orb}/P_{orb}=(-9.9{\pm}3.5){\times}10^{-7}yr^{-1}$. The F-test result shows that the quadratic ephemeris is describes the evolution of the dip phases better than the linear ephemeris at a greater than 95% confidence level. More X-ray data collected from the early 80s will be included to further refine the orbital ephemeris.