YNAO OpenIR研究单元&专题: 中国科学院天体结构与演化重点实验室
http://ir.ynao.ac.cn:80/handle/114a53/7550
2024-03-28T13:36:46Z
2024-03-28T13:36:46Z
The Effect of Irradiation on the Spin of Millisecond Pulsars
Lan SY(兰顺义)
Meng XC(孟祥存)
http://ir.ynao.ac.cn:80/handle/114a53/26351
2023-11-06T08:38:18Z
2023-10-30T06:20:37Z
题名: The Effect of Irradiation on the Spin of Millisecond Pulsars
作者: Lan SY(兰顺义); Meng XC(孟祥存)
摘要: <p>A millisecond pulsar (MSP) is an old neutron star (NS) that has accreted material from its companion star, causing it to spin up, which is known as the recycling scenario. During the mass transfer phase, the system manifests itself as an X-ray binary. PSR J1402+13 is an MSP with a spin period of 5.89 ms and a spin period derivative of logPspin=-16.32 . These properties make it a notable object within the pulsar population, as MSPs typically exhibit low spin period derivatives. In this paper, we aim to explain how an MSP can possess a high spin period derivative by binary evolution. By utilizing the stellar evolution code MESA, we examine the effects of irradiation on the companion star and the propeller effect on the NS during binary evolution. We demonstrate that irradiation can modify the spin period and mass of an MSP, resulting in a higher spin period derivative. These results suggest that the irradiation effect may serve as a key factor in explaining MSPs with high spin period derivatives.</p>
2023-10-30T06:20:37Z
An Exposure Meter of Lijiang Fiber-fed High-Resolution Spectrograph
Yu XG(余晓光)
Ji KF(季凯帆)
Zhang XL(张西亮)
Chang L(常亮)
Cai YF(蔡云芳)
Tan Y(覃瑛)
Shang, Zhen-Hong
http://ir.ynao.ac.cn:80/handle/114a53/26349
2023-10-30T09:23:00Z
2023-10-30T06:20:28Z
题名: An Exposure Meter of Lijiang Fiber-fed High-Resolution Spectrograph
作者: Yu XG(余晓光); Ji KF(季凯帆); Zhang XL(张西亮); Chang L(常亮); Cai YF(蔡云芳); Tan Y(覃瑛); Shang, Zhen-Hong
摘要: <p>In 2016, an exposure meter was installed on the Lijiang Fiber-fed High-Resolution Spectrograph to monitor the coupling of starlight to the science fiber during observations. Based on it, we investigated a method to estimate the exposure flux of the CCD in real time by using the counts of the photomultiplier tubes (PMT) of the exposure meter, and developed a piece of software to optimize the control of the exposure time. First, by using flat -field lamp observations, we determined that there is a linear and proportional relationship between the total counts of the PMT and the exposure flux of the CCD. Second, using historical observations of different spectral types, the corresponding relational conversion factors were determined and obtained separately. Third, the method was validated using actual observation data, which showed that all values of the coefficient of determination were greater than 0.92. Finally, software was developed to display the counts of the PMT and the estimated exposure flux of the CCD in real-time during the observation, providing a visual reference for optimizing the exposure time control.</p>
2023-10-30T06:20:28Z
Grids of Wolf-Rayet Stars Using MESA with the k - ω Model: From 25 to 120 M ⊙ at Z=0.02
Li Z(李志)
Li Y(李焱)
http://ir.ynao.ac.cn:80/handle/114a53/26347
2023-10-30T09:21:43Z
2023-10-23T06:41:01Z
题名: Grids of Wolf-Rayet Stars Using MESA with the k - ω Model: From 25 to 120 M ⊙ at Z=0.02
作者: Li Z(李志); Li Y(李焱)
摘要: <p>To explore overshoot mixing and rotational mixing beyond the convective core during the core He-burning phase in massive stars, we computed a grid of stellar models, both rotating and nonrotating, with the k - omega model at Z = 0.02, covering a mass range of 25-120 M-circle dot. The rotating models start with a rotation rate of v(ini)/v(crit) = 0.4 at the zero-age main sequence, and the evolution is computed until the end of the central carbon-burning phase. Models with the k - omega model provide larger convective cores and a broadening of the main-sequence width. The diffusive-overshoot models with f(ov) = 0.027 are, on average, closer to the k - omega models for massive stars at Z = 0.02, particularly for the stars with masses greater than 40 M-circle dot. The final masses of the Wolf-Rayet (WR) stars range from 9.5-17.5 M-circle dot and 10-23 M-circle dot for the rotating and nonrotating models, respectively. In the rotating models, the C/N ratio decreases slowly below 0.1 outside the convective core, resulting in a flatter element transition region. In addition, the lifetimes of the WNC phase are 1-4 x 10(4) yr, which is about 1 order of magnitude longer than that in the nonrotating models. The masses of the WNC stars are dominated by internal mixing processes and the maximum masses of the He-burning convective cores during the core He-burning phase are in the range of 15-35 M-circle dot. The expected WNC/WR ratios are 0.059 and 0.004 for the rotating and nonrotating models, respectively</p>
2023-10-23T06:41:01Z
Back to Business: SLX 1746-331 after 13 Years of Silence
Peng, Jing-Qiang
Zhang, Shu
Wang, Peng-Ju
Zhang, Shuang-Nan
Kong, Ling-Da
Chen, Yu-Peng
Shui, Qing-Cang
Ji, Long
Qu, Jin-Lu
Tao, Lian
Ge, Ming-Yu
Ma, Rui-Can
Chang, Zhi
Li, Jian
Li, Zhao-sheng
Yu, Zhuo-Li
Yan Z(颜哲)
Zhang, Peng
Xiao, Yun-Xiang
Zhao, Shu-Jie
http://ir.ynao.ac.cn:80/handle/114a53/26344
2023-10-30T09:20:58Z
2023-10-23T06:40:58Z
题名: Back to Business: SLX 1746-331 after 13 Years of Silence
作者: Peng, Jing-Qiang; Zhang, Shu; Wang, Peng-Ju; Zhang, Shuang-Nan; Kong, Ling-Da; Chen, Yu-Peng; Shui, Qing-Cang; Ji, Long; Qu, Jin-Lu; Tao, Lian; Ge, Ming-Yu; Ma, Rui-Can; Chang, Zhi; Li, Jian; Li, Zhao-sheng; Yu, Zhuo-Li; Yan Z(颜哲); Zhang, Peng; Xiao, Yun-Xiang; Zhao, Shu-Jie
摘要: <p>The black hole candidate system SLX 1746-331 was back to business in 2023, after a long silence of roughly 13 years. An outburst was observed thoroughly by Insight-HXMT and NICER. The outburst is characterized by spectral dominance of the soft state, where the joint Insight-HXMT and NICER spectral analysis shows the temperature dependence of the disk flux follows Tin3.98 , and thus suggests that the inner disk reaches its innermost stable circular orbit during almost the entire outburst. By assuming 0.3 L Edd for the peak flux and an inclination angle of zero degrees, the lower limit of the compact object hosted in this system is estimated as 3.28 & PLUSMN; 2.14 M & ODOT;. We also look into the relation between the disk temperature and disk flux for a sample of black hole systems, and by taking the disk temperature derived in the outburst of SLX 1746-331, such a relation results in a mass estimation of 5.2 & PLUSMN; 4.5 M & ODOT;. Finally, the spin of the compact object is constrained to be larger than 0.8 with the spectral model KERRBB.</p>
2023-10-23T06:40:58Z
Study of Advective Energy Transport in the Inflow and Outflow of Super-Eddington Accretion Flows
Jiao CL(焦承亮)
http://ir.ynao.ac.cn:80/handle/114a53/26332
2023-10-30T06:34:30Z
2023-10-23T06:40:37Z
题名: Study of Advective Energy Transport in the Inflow and Outflow of Super-Eddington Accretion Flows
作者: Jiao CL(焦承亮)
摘要: <p>Photon trapping is believed to be an important mechanism in super-Eddington accretion, which greatly reduces the radiative efficiency as photons are swallowed by the central black hole before they can escape from the accretion flow. This effect is interpreted as the radial advection of energy in one-dimensional height-integrated models, such as the slim-disk model. However, when multidimensional effects are considered, the conventional understanding may no longer hold. In this paper, we study the advective energy transport in super-Eddington accretion based on a new two-dimensional inflow–outflow solution with radial self-similarity, in which the advective factor is calculated self-consistently by incorporating the calculation of radiative flux instead of being set as an input parameter. We found that radial advection is actually a heating mechanism in the inflow due to compression, and the energy balance in the inflow is maintained by cooling via radiation and vertical (θ-direction) advection, which transports entropy upward to be radiated closer to the surface or carried away by the outflow. As a result, fewer photons are advected inward, and more photons are released from the surface, so that the mean advective factor is smaller and the emergent flux is higher than the fluxes predicted by the slim-disk model. The radiative efficiency of super-Eddington accretion thus should be higher than that of the slim-disk model, which agrees with the results of some recent numerical simulations.</p>
2023-10-23T06:40:37Z
Fundamental parameters of 318 contact binaries from the TESS survey
Ding X(丁旭)
Ji KF(季凯帆)
Li, XuZhi
Xiong JP(熊建萍)
Cheng QY(程其原)
Wang JL(王锦良)
http://ir.ynao.ac.cn:80/handle/114a53/26327
2023-11-06T08:34:25Z
2023-10-23T02:46:24Z
题名: Fundamental parameters of 318 contact binaries from the TESS survey
作者: Ding X(丁旭); Ji KF(季凯帆); Li, XuZhi; Xiong JP(熊建萍); Cheng QY(程其原); Wang JL(王锦良)
摘要: <p>The TESS Survey has released a large number of high-precision light curves of contact binaries. However, using the Phoebe program and Markov chain Monte Carlo (MCMC) algorithm to obtain the posterior distribution of contact binary parameters is a time-consuming process. In order to obtain the contact binary parameters from the TESS survey, we build neural network (NN) models and combine them with the MCMC algorithm to obtain the contact binary parameters and parameter errors quickly. NN model is used in place of the physical model, which can generate a light curve with a precision of less than a millimagnitude. The NN model is capable of generating light curves at a speed that is four orders of magnitude faster than Phoebe running on the same computing platform. In this study, we have determined the parameters of 318 contact binary systems exhibiting relatively symmetric light curves. Subsequently, a statistical analysis was conducted on the derived parameters of these 318 targets. The coefficient of determination (R-2) for 318 contact binaries between the light curves generated by Phoebe using these parameters obtained by the NN model and MCMC as inputs and the original light curves is greater than 0.99. Additionally, the distribution and correlation of the parameters for these 318 contact binary systems have been presented.</p>
2023-10-23T02:46:24Z
Investigation into the reflection properties of the neutron star low-mass X-ray binary 4U 1636-53
Lyu, M.
Zhang GB(张国宝)
Wang, H. G.
García, F.
http://ir.ynao.ac.cn:80/handle/114a53/26326
2023-10-23T03:05:38Z
2023-10-23T02:46:23Z
题名: Investigation into the reflection properties of the neutron star low-mass X-ray binary 4U 1636-53
作者: Lyu, M.; Zhang GB(张国宝); Wang, H. G.; García, F.
摘要: <p>We present the spectroscopy of the neutron star low-mass X-ray binary 4U 1636-53 using six simultaneous XMM-Newton and Rossi X-ray Timing Explorer observations. We applied different self-consistent reflection models to explore the features when the disk is illuminated by either the corona or the neutron star surface. We found that the spectra could be well fitted by these two types of models, with the derived emissivity index below a typical value of 3. The relative low emissivity can be explained if the neutron star and the corona, working together as an extended illuminator, simultaneously illuminate and ionize the disk. Additionally, the derived ionization parameter in the lamppost geometry is larger than the theoretical prediction. This inconsistency likely suggests that the corona does not emit isotropically in a realistic context. Furthermore, we also found that there is a possible trend between the height of the corona and the normalization of the disk emission. This could be understood either as a variation in the reflected radiation pressure or in the context of a jet base. Finally, we found that the disk is less ionized if it is illuminated by the neutron star, indicating that the illuminating source has significant influence on the physical properties of the disk. © The Authors 2023.</p>
2023-10-23T02:46:23Z
An Initial Analysis of a Strongly Lensed QSO Candidate Identified by LAMOST
Chen, Y. H.
Tang, M. Y.
Shu, H.
Tu, H.
http://ir.ynao.ac.cn:80/handle/114a53/26325
2023-10-23T03:15:02Z
2023-10-23T02:43:51Z
题名: An Initial Analysis of a Strongly Lensed QSO Candidate Identified by LAMOST
作者: Chen, Y. H.; Tang, M. Y.; Shu, H.; Tu, H.
摘要: <p>From 2011 to 2021, LAMOST has released a total of 76,167 quasar data. We try to search for gravitationally lensed QSOs by limiting coordinate differences and redshift differences of these QSOs. The name, brightness, spectrum, photometry and other information of each QSO will be visually checked carefully. Special attention should be paid to check whether there are groups of galaxies, gravitationally lensed arcs, Einstein crosses, or Einstein rings near the QSOs. Through careful selection, we select LAMOST J160603.01+290050.8 (A) and LAMOST J160602.81+290048.7 (B) as a candidate and perform an initial analysis. Components A and B are 3.'' 36 apart and they display blue during photometric observations. The redshift values of components A and B are 0.2% different, their Gaia_g values are 1.3% different, and their ugriz values are 1.0% or less different. For the spectra covering from 3690 to 9100 & Aring;, the emission lines of C II, Mg, H gamma, O III, and H beta are present for both components A and B and the ratio of flux(B) to flux(A) from LAMOST is basically a constant, around 2.2. However, no galaxies have been found between components A and B. Inada et al. identified them as binary quasars. But we accidentally find a galaxy group near components A and B. If the center of dark matter in the galaxy group is at the center between components A and B, components A and B are probably gravitationally lensed QSOs. We estimate that the Einstein mass is 1.46 x 10(11) M (circle dot) and the total mass of the lens is 1.34 x 10(13) M (circle dot). The deflection angle is 1.'' 97 at positions A and B and the velocity dispersion is 261 km s(-1). Theoretically, this candidate could be a pair of fold images of a strong lensing system by a galaxy group, and we will investigate the possibility when the redshifts of nearby galaxies are available.</p>
2023-10-23T02:43:51Z
A Study of Ten Early-type Contact Binary Stars in the Small Magellanic Cloud
Wu CQ(吴楚齐)
Li FX(李福兴)
Qian SB(钱声帮)
Zhang J(张嘉)
Sarotsakulchai, Nopphadon
Zubairi, Ahmed Waqas
AZIZBEK MATEKOV
http://ir.ynao.ac.cn:80/handle/114a53/26324
2023-10-23T03:01:25Z
2023-10-23T02:43:49Z
题名: A Study of Ten Early-type Contact Binary Stars in the Small Magellanic Cloud
作者: Wu CQ(吴楚齐); Li FX(李福兴); Qian SB(钱声帮); Zhang J(张嘉); Sarotsakulchai, Nopphadon; Zubairi, Ahmed Waqas; AZIZBEK MATEKOV
摘要: <p>To study early-type binary systems in different evolutionary stages or environments, the Small Magellanic Cloud (SMC) is an ideal laboratory due to its low metallicity compared to that of the Milky Way. We conduct a study on the period changes of the close binary systems with B-type spectral classifications in the SMC using OGLE collections. Ten B-type binaries that show no significant periodic variations based on the current observational data were analyzed. Through O - C analysis, four of the ten early-type binaries show a long-term period decrease, one shows a long-term period increase, and the other five systems are ambiguous due to the limitations of the observational data. Among the period-decreasing systems, two may be mainly caused by mass transfer, while the rest may be caused by angular momentum loss. The Wilson-Devinney code (W-D method) is used to analyze their I-band photometric light curves. According to the W-D results, five early-type binaries are in the deep contact state, three are in the shallow contact state, while two are in the medium contact state, and the temperature ratios of these early-type binaries are all close to unity. The five deep contact binaries are highly unstable systems and therefore serve as important objects for the study of binary mergers. Finally, a discussion on the evolution of early-type binary stars is conducted by combining the analyses of the light curves and the periodic changes of ten early-type binaries, that implies that the majority of early-type binaries in the SMC may form contact binaries from a phase of rapid mass transfer.</p>
2023-10-23T02:43:49Z
Matter ejections behind the highs and lows of the transitional millisecond pulsar PSR J1023+0038
Baglio, M. C.
Coti Zelati, F.
Campana, S.
Busquet, G.
D' Avanzo, P.
Giarratana, S.
Giroletti, M.
Ambrosino, F.
Crespi, S.
Miraval Zanon, A.
Hou X(侯贤)
Li, D.
Li, J.
Wang, P.
Russell, D. M.
Torres, D. F.
Alabarta, K.
Casella, P.
Covino, S.
Bramich, D. M.
De Martino, D.
Méndez, M.
Motta, S. E.
Papitto, A.
Saikia, P.
Vincentelli, F.
http://ir.ynao.ac.cn:80/handle/114a53/26219
2023-10-23T03:12:14Z
2023-10-07T07:28:20Z
题名: Matter ejections behind the highs and lows of the transitional millisecond pulsar PSR J1023+0038
作者: Baglio, M. C.; Coti Zelati, F.; Campana, S.; Busquet, G.; D' Avanzo, P.; Giarratana, S.; Giroletti, M.; Ambrosino, F.; Crespi, S.; Miraval Zanon, A.; Hou X(侯贤); Li, D.; Li, J.; Wang, P.; Russell, D. M.; Torres, D. F.; Alabarta, K.; Casella, P.; Covino, S.; Bramich, D. M.; De Martino, D.; Méndez, M.; Motta, S. E.; Papitto, A.; Saikia, P.; Vincentelli, F.
摘要: <p>Transitional millisecond pulsars are an emerging class of sources that link low-mass X-ray binaries to millisecond radio pulsars in binary systems. These pulsars alternate between a radio pulsar state and an active low-luminosity X-ray disc state. During the active state, these sources exhibit two distinct emission modes (high and low) that alternate unpredictably, abruptly, and incessantly. X-ray to optical pulsations are observed only during the high mode. The root cause of this puzzling behaviour remains elusive. This paper presents the results of the most extensive multi-wavelength campaign ever conducted on the transitional pulsar prototype, PSR J1023 +0038, covering from the radio to X-rays. The campaign was carried out over two nights in June 2021 and involved 12 di fferent telescopes and instruments, including XMM-Newton, HST, VLT /FORS2 (in polarimetric mode), ALMA, VLA, and FAST. By modelling the broadband spectral energy distributions in both emission modes, we show that the mode switches are caused by changes in the innermost region of the accretion disc. These changes trigger the emission of discrete mass ejections, which occur on top of a compact jet, as testified by the detection of at least one short-duration millimetre flare with ALMA at the high-to-low mode switch. The pulsar is subsequently re-enshrouded, completing our picture of the mode switches.</p>
2023-10-07T07:28:20Z