“X射线天文学60周年及中国X射线天文研究”研讨会：时域与多信使天文学时代的X射线天文研究

15 Jun 2022, 08:00 → 19 Jun 2022, 18:00 Asia/Shanghai

张澍

        1962年6月18日，贾科尼等人利用探空火箭搭载的X射线探测器第一次看到了太阳系外的X射线源——天蝎座X-1，标志着X射线天文学的诞生。1970年12月，人类第一颗X射线天文卫星Uhuru上天，迄今已经发射近百个X射线天文卫星或空间探测器，革新了人类对宇宙的认识。我国自1970年代末开始利用高空气球进行空间硬X射线观测；2001年，“神舟二号”搭载太阳和宇宙天体高能辐射监测仪在轨运行半年，标志着我国在轨空间X射线天文观测“零”的突破；2016年，空间实验室“天宫二号”上的伽马射线暴偏振探测器POLAR在轨运行；2017年6月15日，我国自主研制的首颗X射线天文卫星“慧眼”HXMT成功发射，开启了黑洞、中子星X射线双星的硬X射线快速光变和能谱研究的新窗口，取得了一系列重要的科学成果；2020年12月，“怀柔一号”（GECAM）卫星上天。爱因斯坦探针（EP）卫星、空间变源监视器（SVOM）卫星将在今后1-2年上天，中欧合作旗舰级X射线天文卫星——增强型X射线时变与偏振（eXTP）空间天文台以及几个其他类型的X射线天文卫星正在预研之中。我国的X射线天文学正处于大发展的时期。

        值此X射线天文学60年之际，中国天文学会空间天文和高能天体物理专业委员会和中国空间科学学会空间天文学专业委员会计划于2022年6月15-18日在“中国高等科学技术中心”（位于北京中关村）召开“X射线天文学60周年及中国X射线天文研究”研讨会：时域与多信使天文学时代的X射线天文研究（The 60th Anniversary of X-Ray Astronomy: X-ray Astronomy in the Time-domain & Multi-messenger Era）。该研讨会由中科院粒子天体物理重点实验室和空间天文与技术重点实验室联合承办，采取“线上-线下相结合”的方式召开。

      会议主题：

1. X射线双星
2. 非吸积脉冲星、磁星和快速射电暴
3. 高能爆发现象
4. 活动星系核与超大质量黑洞
5. 多信使天文学与多波段联合观测
6. 探测设备与技术

Wednesday, 15 June

Session I

Convener: Chair: 张双南

1 致辞

2 中国X射线天文和空间天文的一些情况

中国X射线天文和空间天文的一些情况

Speaker: 顾逸东

3 慧眼研究进展

Speaker: 张澍

Slides 慧眼研究进展

4 极目和慧眼极端暴发观测研究

Speaker: 熊少林 (高能所)

10:40 Break

Session II

Convener: Chair: 崔伟

5 Highlights of MAXI

Speaker: Tatehiro Mihara

Slides MAXI Highlights

6 “极光”的偏振观测结果

Speaker: 冯骅

Slides PolarLight and Science results

7 SVOM status update

Speaker: 魏建彦

8 Einstein Probe: Exploring the ever-changing X-ray Universe

The Einstein Probe (EP) is a small satellite dedicated to time-domain astronomy to monitor the sky in the soft X-ray band. It is a mission led by the Chinese Academy of Sciences and developed in its space science programme with international collaboration. Its wide-field imaging capability is achieved by using established technology of the micro-pore lobster-eye X-ray focusing optics. Complementary to this is deep X-ray follow-up capability enabled by a Wolter-I type X-ray telescope. EP is also capable of fast transient alerts triggering and downlink, aiming at multi-wavelength follow-up observations by the world-wide community. EP will enable systematic survey and characterisation of high-energy transients at unprecedented sensitivity, spatial resolution, grasp and monitoring cadence. Its scientific goals are mainly concerned with discovering new or rare types of transients, including tidal disruption events, supernova shock breakouts, high-redshift GRBs, and of particular interest, electromagnetic sources of gravitational wave events. The mission is scheduled for launch by the end of 2023.

Speaker: 刘元 (中国科学院国家天文台)

Slides Einstein Probe: Exploring the ever-changing X-ray Universe

12:40 Lunch

Session III

Convener: Chair: 张澍

9 Jets, winds, and flares from black hole accretion flows

The hard and quiescent states of black hole X-ray binaries and most supermassive black holes in the nearby universe are powered by hot accretion flows. In this talk, I will review wind and jet launched from this type of accretion flow, including both their theoretical studies and observaitonal evidences. For winds, we will introduce their launching mechanism and main properties such as mass flux and velocity. For jets, in addition to the continuous jets, we will focus more on the formation mechanism of epsodic jets and the associated flares.

Speaker: 袁峰 (Shanghai Astronomical Observatory)

Slides Wind, jet, and flares from black hole accretion flows

10 伽马射线双星LS I +61 303的多波段观测研究

伽马射线射线双星是X射线双星的一个特殊子类，它们在各个波段都有很强的辐射，适合多波段观测研究。 LS I +61 303是伽马射线双星中最为特殊的一个源，受到国内外众多学者的关注、研究，是国内多个（不同波段）望远镜的重要观测对象。最近，我们利用FAST在LS I +61 303方向首次探测到脉冲信号，说明系统中很可能存在一个年轻的强磁场中子星。在此基础上，我们利用FAST和慧眼卫星对其进行长期监测，希望进一步深入了解该系统。

Speaker: 翁山杉 (NJNU)

Slides 伽马射线双星LS I +61 303的多波段观测研究

11 The puzzling low luminosity accretion in black hole X-ray binaries

It has been well known for a long time that a black hole X-ray binary stays in the hard state when the luminosity is low (below around one percent of LEdd). The X-ray spectrum is dominated by the inverse Compton emission from a hot corona, which is very different from the thermal dominated spectrum from Shakura-Sunyaev disk at higher luminosity. In recent years, however, some observational results challenge the current understanding of low luminosity accretion. One is that the transition between the hard (Compton dominated) and soft (thermal dominated) state is discovered in the mini-outbursts of some black hole X-ray binaries with the luminosity range 10-5-10-3 LEdd and even lower, which detected above 1% LEdd before. The other one is that the electron temperature of the hot corona is positively correlated with the X-ray luminosity at the low luminosity regime, which contradicts with the expectation of current models. Therefore, our recent observational results make the low luminosity accretion still puzzling.

Speaker: 闫震 (Shanghai Astronomical Observatory)

Slides The puzzling low luminosity accretion in black hole X-ray binaries

12 Towards Precision Measurements of Accreting Black Holes Using X-Ray Reflection Spectroscopy

Speaker: Cosimo Bambi

Slides Towards Precision Measurements of Accreting Black Holes Using X-Ray Reflection Spectroscopy

13 Rapidly alternating flux states of GX 339–4 during its 2021 outburst captured by Insight–HXMT

The low mass X-ray binariy GX 339-4 entered a new outburst in 2021. At the end of the hard to soft transition of this outburst, Insight-HXMT found that the source rapidly alternated between low flux and high flux states on a timescale of hours. Two high flux states lasted only for a period comparable to the orbital period of the observatory. Time-resolved spectral analysis shows that the sudden changes of flux are confined in the hard X-ray band (> 4 keV). The variable non-thermal emission, including the power-law continuum from the corona and the reflected emission from the inner accretion disk, is responsible for the observed variability. The strength of the disk thermal emission and the inner radius of the accretion disk are consistent between the two flux states. Assuming the lamppost geometry, our best-fit disk reflection models suggest a very low corona height (within 3 Rg) and there is no evidence of significant variation in the corona geometry either. The observed rapidly alternating flux states suggest that the intrinsic power of the corona must change during the state transition.

Speaker: 刘鸿辉 (Fudan University)

Slides Rapidly alternating flux states of GX 339–4 during its 2021 outburst

14 Applications of the Insight-HXMT data

The main methods applied to study X-ray binaries are timing and spectral analysis. Compared to other instruments, Insight-HXMT covers a broad energy band from 1 to 250 keV with a high time resolution and a moderate spectral resolution. Moreover, Insight-HXMT does not suffer from strong pileup effects and instrumental dead time. We have taken these advantages of Insight-HXMT to study two black hole transients, MAXI J1820+070 and EXO 1846-031. In the former case, we found that the hard lags, with a timescale of tens of milliseconds, are significantly correlated to the photon index, suggesting the lags originate from Comptonization in a jet. In the latter case, together with the NuSTAR data, we observed a variable ionized disk wind, appearing in the hard-intermediate state and disappearing in the soft state. More details will be present in the talk.

Speaker: 王亚楠 (University of Sounthampton)

Slides Applications of the Insight-HXMT data

15:40 Break

Session IV

Convener: Chair: 王伟

15 爆发极冠区吸积物理和回旋吸收线

Speaker: Andrea Santangelo

16 Progress and Future to Stellar BH Spin Measurement

Speaker: 苟利军 (National Astronomical Observatory of China)

Slides Progress and Future to Stellar BH Spin Measurement

17 MAXI J1631-479爆发演化

Speaker: 卜庆翠 (Eberhard Karls University Tübingen Physikalisches Institut)

Slides On the inclination dependence of QPO properties

18 The wavelet technique and QPO properties probed with Insight-HXMT observation

The wavelet analysis is used to study spectral-timing properties of MAXI J1535-571 observed by Insight-HXMT. The low-frequency quasi-periodic oscillations (QPOs) are detected in nine observations. Based on wavelet analysis, the time intervals with QPO and non-QPO are isolated separately, and the corresponding spectra with QPO and non-QPO are analyzed. We find that the spectra with QPO (hereafter QPO spectra) are softer than those without QPO (hereafter non-QPO spectra) in the hard intermediate state (HIMS). While in the soft intermediate state (SIMS), the QPO spectra are slightly harder. The disk temperature of QPO regime is slightly lower during HIMS, but becomes higher during SIMS. The cutoff energies of QPO spectra and non-QPO spectra do not show significant differences. The flux ratio of the disk to total flux is higher for the time intervals with non-QPO than that of QPO regime. We propose that these differences in the spectral properties between QPO and non-QPO regimes could be explained in the scenario of Lense-Thirring precession, and the reversal of the QPO/non-QPO behavior between HIMS and SIMS may be associated with appearance/disappearance of a type-B QPO which might origin from the precession of the jet.

Speaker: 陈骁 (Wuhan University)

Slides The wavelet technique and QPO properties probed with Insight-HXMT observation

19 X-ray search for intermediate-mass black holes

Two distinct environments are the best searching ground for active (X-ray bright) intermediate mass black holes (IMBHs): the nuclei of late-type disk galaxies and the outskirts of spheroidal or elliptical galaxies. i) In late-type spirals, the identification of candidate IMBH host galaxies is based on scaling relations (M-sigma relation, M_{star}-M_{BH} relation, pitch angle), and point-like X-ray detections confirm or at least suggest the presence of a compact object in the galactic nucleus. I give an example of such candidates we have identified in the Virgo Cluster. ii) Off-nuclear IMBHs may be the result of satellite accretion during the assembly of a galactic halo. Focusing the X-ray search on elliptical/spheroidal galaxies reduces the possibility of confusion with stellar-mass super-Eddington sources (ultraluminous X-ray sources), which are more often associated with young stellar populations. Here, the identification of candidate IMBHs is based on their soft, thermal (disk-blackbody) X-ray spectrum with peak temperatures T_{in} ~ 0.2-0.4 keV at a luminosity L_X ~ 1E41-1E42 erg/s. I will give an example of the two best candidates identified so far through this method.

Speaker: Roberto Soria (U)

Slides X-ray searches of intermediate mass BHs

Thursday, 16 June

Session I

Convener: Chair: 李向东

20 X-ray view of galaxies near and far

I'll give a brief personal overview of X-ray source populations seen in nearby and very distant galaxies.

Speaker: Daniel Wang (U)

Slides X-ray view of galaxies near and far

21 The outflowing corona in MAXI J1820+070

A black hole X-ray binary (BHXRB) produces hard X-ray radiation from its corona and disk when the accreted matter heats up. During an outburst, the disk and corona co-evolves with each other. However, such an evolution is still unclear in both its geometry and dynamics. Here we report the unusual decrease of the reflection fraction in MAXI J1820+070, which is the ratio of the coronal intensity illuminating the disk to the coronal intensity reaching the observer, as the corona is observed to contract during the decay phase. In the scenario of outflowing corona, the decrease of the reflection fraction is a signature of the corona’s bulk velocity. Our findings suggest that as the corona is observed to get closer to the black hole, the coronal material might be outflowing faster.

Speaker: 游贝 (Wuhan University)

Slides The outflowing corona in MAXI J1820+070

22 MAXIJ1820+070爆发的高能QPO和进动喷流

Speaker: 马想 (IHEP)

Slides MAXIJ1820+070爆发的高能QPO和进动喷流

23 黑洞吸积盘的辐射磁流体力学数值模拟

黑洞X射线双星的吸积过程涉及复杂的磁流体过程，需要借助数值模拟来理解其物理本质。我们进行了一个围绕7倍太阳质量黑洞周围吸积盘的三维辐射磁流体数值模拟，吸积率范围是从1%到接近临界值。在所有的模拟中，由磁旋转不稳定性导致的湍流造成了角动量的转移，最终形成了稳定的吸积盘结构。模拟在10 rg处的没有显示出明显的热不稳定性。我们发现吸积盘的纵向结构都由磁压梯度支撑，并且磁压的模拟值和磁压主导吸积盘模型的理论值相符。在近临界吸积模拟中，旋转轴附近的漏斗形区域内产生了速度为0.1倍光速左右的外流，这与X射线双星观测到的高速外流一致；外流速度的峰值出现在旋转轴附近，但外流携带质量流的峰值则出现在漏斗状区域的边缘处。

Speaker: 黄佳辉 (æ)

Slides 黑洞吸积盘的辐射磁流体力学数值模拟

24 A particular stellar-mass black hole GRS 1915+105: 15 years of X-ray and radio monitoring

GRS 1915+105 is a particular stellar-mass black hole in a binary system. This source has been active since its discovery in 1992, and shows complex timing and spectral properties that are quite different from other black hole binaries. We collected 15 years of data from RXTE (X-ray) and Ryle (radio) telescope to reveal a strong correlation between (i) the radio flux that comes from the jet and the flux of the iron emission line that comes from the disk and (ii) the temperature of the hard X-ray corona and the amplitude of a high-frequency variability component that comes from the innermost part of the accretion flow. Our findings show that the energy that powers this black hole system can be directed in different proportions either mainly to the X-ray corona or to the jet. These facts, plus our modelling of the variability in this source, suggest that in GRS 1915+105 the X-ray corona turns into the jet.

Speaker: 张亮 (Ihep)

Slides A particular stellar-mass black hole GRS 1915+105: 15 years of X-ray and radio monitoring

25 Low Frequency Quasi-periodic Oscillations in MAXI J1820+070: Evidence for both Comptonization and Reflection contributions

Low Frequency (LF) quasi-periodic oscillations (QPOs) of black hole X-ray binaries, especially the C-type LF QPOs seen in many black hole transients during outbursts, are representative timing signals of black hole low/hard state and intermediate state. The most popular model for the C-type LF QPOs is the Lense-Thirring precession model, which attributes the QPO as due to the precession of a torus of the hot flow in the vicinity of the black hole. Here we report our analysis of one of the Insight-HXMT observations of the black hole transient MAXI J1820+070 in which the source X-ray count rate was among the highest while the C-type LF QPO was strong and at a relatively low frequency. We applied a disk reflection spectral model to fit the energy spectra corresponding to the high flux and the low flux phase of the C-type low frequency QPOs, respectively. With the hard X-ray energy band coverage of the Insight-HXMT, we found the modulation of the extended to 150 keV energy spectrum components. Detailed analysis indicates that in the hard band (about > 60 keV) LF QPO modulation appears primarily in the Comptonization spectral component if not alone while in the soft band the modulation is seen in both components.

Speaker: 高晨旭 (Shanghai Astronomical Observatory)

10:40 Break

Session II

Convener: Chair: 余文飞

26 Disk-jet coupling in Galactic Black Hole transients in the era of SKA

Galactic Black Hole (BH) transients show coupling between the generation of jets and the processes of accreting (i.e., disk-jet coupling) around the central engines. During their hard and quiescent states the radio emission from the compact jets are non-linearly correlated to the X-ray emission from the inner accretion flow, which as an observational tool plays an unparalleled role in supporting and understanding disk-jet coupling. In this talk, I will be firstly showing you the general picture of such coupling for these transients mainly in observation, and some associated physical attempts invoked. Then, I will give case studies for a few BH transients based on our MeerKAT (a SKA precursor telescope) radio and coordinated X-ray observations under the MeerKAT Large Survey Project—ThunderKAT, highlighting how MeerKAT and near-future radio arrays (e.g., SKA and ngVLA) are trying to pin down some unanswered questions, such as: (1). The underlying physical mechanism of disk-jet coupling and jet production; (2). Why are the ‘radio-quiet’ branch BHs producing less powerful jets under the same accretion conditions as others; (3). Why some neutron stars behave like BHs in the fundamental plane while others not.

Speaker: 张先 (Shanghai Astronomical Observatory)

27 Insight-HXMT discovery of the highest energy CRSF from the first Galactic ultra-luminous X-ray pulsar Swift~J0243.6+6124

Measuring the cyclotron resonance scattering feature (CRSF) is the only way to measure directly and reliably the magnetic field near the surface of a neutron star (NS). With the broad energy coverage and large hard X-ray collection area of Insight-HXMT, we have discovered so far the highest energy CRSF up to about 146 keV during the 2017 outburst of the first galactic ultra-luminous X-ray (ULX) pulsar Swift J0243.6+6124. In comparison, the two previous records of highest energy detection of CRSF with more than 5 sigma significance were also both set by Insight-HXMT: the 90 keV fundamental CRSF from GRO J1008-57 and the 100 keV first harmonic of CRSF from 1A 0535+262. During the outburst of Swift J0243.6+6124, the CRSF was significantly detected when the outburst peaked at luminosity 2*10^39 erg/s. The CRSF was seen in a spin phase region of the main peak, and its centroid energy evolves with phase from 120 to 146 keV, which we identify as the fundamental CRSF since no spectral feature exists at 60-70 keV. This is the first unambiguous detection of electron CRSF from ULXs, and a surface magnetic field 1.6*10^13 G is estimated for Swift J0243.6+6124. Such a strong dipole magnetic field prevents the spherization by radiation pressure in its accretion disk even during its outburst peak, which has been speculated as the source of outflows in NS ULX systems. Without outflows, the observed high luminosity should be intrinsic and not particularly beamed in a small solid angle as proposed previously.

Speaker: 孔令达 (IHEP)

Slides Insight-HXMT discovery of the highest energy CRSF from the first Galactic ultra-luminous X-ray pulsar Swift~J0243.6+6124

28 Insight-HXMT observations on type-I & type-II X-ray bursts

Since the midyead of 2017, Insight-HXMT has observed tens NS X-ray binaries. Among them, hundreds X-ray bursts, including type-I and typ-II bursts, are detected. In a type-I X-ray burst of 4U 1636--536, a shortage at hard X-ray burst is obsersed, which is the first detection in single burst since the privious results are obtined by stacking tens of hundreds bursts of RXTE/INTEGRAL. Also, among tens type-I bursts and hundreds type-II bursts are detected by Insight-HXMT, several interesting results will be given in this talk.

Speaker: 陈玉鹏 (IHEP)

Slides Insight-HXMT observations on type-I & type-II X-ray bursts

29 On the origin of pulsating ultraluminous X-ray pulsars

Ultraluminous X-ray sources (ULXs) are off-nucleus objects whose apparent X-ray luminosity exceeds 10^39 erg/s, the Eddington limit of a typical stellar mass black hole (∼10 Msun). Recent studies revealed that some of them are accreting neutron stars (NSs), called pulsating ULXs (PULXs), the luminosity of which is usually more than ∼ 2-3 orders of magnitude higher than most Galactic and nearby accreting X-ray pulsars. It has been suggested that the NSs in PULXs have very high surface magnetic fields, higher than that of the regular accreting NSs (∼ 10^12 G), or even comparable to that of magnetars (∼ 10^14 G), in order to explain their extremely high luminosity. Some other models of PULXs include strongly collimated radiation such that the intrinsic luminosity is much lower than that directly inferred from the observed X-ray flux. Here, we report the detection of pulsed X-ray emission from 1 keV to above 130 keV from the PULX RX J0209.6−7427 in the SMC using insight-HXMT data, which is the highest energy emission detected from any PULXs. We demonstrate that its main pulsed X-ray emission is not strongly collimated, the same conclusion can also be extended reliably to other ultraluminous accreting X-ray pulsars. We find that, RX J0209.6-7427, together with the other two similar Galactic and nearby PULXs, Swift J0243.6+6124 and SMC X-3, they have experienced large luminosity changes from well below their Eddington limit to super-Eddington and their maximum luminosity fills the luminosity gap between Galactic pulsars and extragalactic PULXs. We also find that all these pulsars share the same range of inferred surface magnetic fields (∼10^12-13 G). Our results suggest that all these sources belong to the same class of accreting pulsars, and the high luminosity of extragalactic PULXs only samples the very rare bright accreting X-ray pulsars in those galaxies.

Speaker: 侯贤 (云南天文台)

30 Accretion in X-ray binaries: The geometry and the spectra

X射线双星是恒星级致密天体（恒星级黑洞和中子星）的重要载体，对X射线双星吸积过程的研究对探索恒星级黑洞和中子星周围强引力场中物质的运动规律具有非常重要的意义。在本报告中，我们将在吸积盘蒸发/冕凝聚模型的框架下讨论X射线双星表现出的一些基本观测特征，例如，吸积盘的截断、光谱态转变，以及与光谱态密切相关的相对论喷流的形成与消失等的物理机制。同时,由于中子星存在一个硬的物质表面，而黑洞存在一个视界面，我们将讨论中子星X射线双星由于硬表面的存在而表现出的一些和黑洞X射线双星显著不同的观测现象背后的基本物理过程。最后，我们将简单分析Insight-HXMT时代一些有待进一步探索的关于X射线双星吸积物理的研究内容，以及未来EP和eXTP等对致密天体吸积物理研究的意义。

Speaker: 乔二林 (NAOC)

Slides Accretion in X-ray binaries: The geometry and the spectra

31 GX 301-2中子星的辐射与内部结构--从回旋吸收线到磁倾角测量

我将报告使用慧眼HXMT对大质量X射线双星GX 301-2进行的一系列观测研究。GX 301-2系统中的中子星在$40-60\,\rm keV$有复杂的回旋吸收结构，其可以被两个高斯吸收描述。我们的研究发现，两个高斯吸收峰的位置会随中子星X射线光度的增加而演化，低光度时正相关，而高光度时反相关，这可以用亚临界和超临界吸积的转变来描述；我们由此测得了临界光度并获得了中子星磁场的估计值。除此之外，我们发现这两个高斯吸收峰的中心能量比值趋于定值，这意味着回旋吸收线的谱型随着光度和双星系统的轨道相位没有显著的变化。我们说明，这种谱型可以用过去已经发表的吸积柱模型很好地再现。定比值现象的来源是中子星的视倾角和磁倾角以及相对论效应的联合，这些效应导致观测者只能看到特定出射角的辐射，进而产生了特定的观测谱型。我们提出，在合理假设下，利用回旋线的谱型以及脉冲轮廓，可以有效限制中子星的磁倾角。通过这一方法，我们成功将中子星的X射线辐射与其内部物理结构联系了起来。

Speaker: 丁远泽 (Wuhan University)

Slides GX 301-2中子星的辐射与内部结构--从回旋吸收线到磁倾角测量

12:30 Lunch

Session III

Convener: Chair: 冯骅

32 KHz QPOs & millisecond X-ray pulsars in LMXBs

The kilohertz quasi-periodic oscillations (kHz QPOs) and spin frequwncies have been found in neutron stars low mass X-ray binaries (NS-LMXBs), which present the millisecond timing phenomena close to the surface of the compact objects. We summarize the following contents: (1). The correlations and distributions of twin kHz QPOs; (2). The relations of high-low frequency QPOs; (3). The QPO properties of NS Atoll and Z sources; (4). Relations between NS spins and QPOs; (5). The mechanisms of kHz QPOs; (6). The implications of kHZ QPOs, e.g., NS mass and radius, disk thickness and magnetic field of Atoll and Z source.

Speaker: 张承民

Slides KHz QPOs & millisecond X-ray pulsars in LMXBs

33 Sco X-1中kHz QPO观测性质研究

慧眼卫星首次在最高能段（>20 keV）探测到了kHz QPO信号，这对kHz QPO起源于吸积盘内边缘的理论模型提出挑战。利用慧眼和RXTE卫星数据，确认了6 keV以下不存在kHz QPO信号，说明它不会直接来源于吸积盘或中子星表面；通过能谱和rms谱的联合拟合，将kHz QPO的起源定位于转换层内侧，进而提出一个新的kHz QPO模型。

Speaker: 贾淑梅 (IHEP)

Slides Insight-HXMT & RXTE Sco X-1中kHz QPO观测性质研究

34 Cyclotron Resonant Scattering Feature in Be X-ray pulsar GRO J1008-57

回旋吸收线是直接测量中子星表面超强磁场的唯一手段，也是研究中子星吸积物理及辐射性质的重要工具。GRO J1008-57是一个Be X-ray pulsar的暂现源，中子星自转周期93秒。慧眼X射线卫星在该天体2017年的II型X射线爆发中观测到能量达90 keV的回旋吸收线，暗示其表面磁场强度超过10^13 G，是目前测量的最高磁场强度。中子星的回旋吸收线能量是不断演化，随X射线光度有一定相关性；GRO J1008-57的回旋吸收线能量与X射线光度呈现一个复杂的演化，小于5e37 erg/s时回旋吸收线能量与光度是反相关，大于该光度时则是正相关。该演化关系与现有吸积柱模型不吻合，我们认为吸积柱几何变化可以导致谱线能量的位移。

Speaker: 王伟 (WHU)

Slides Cyclotron Resonant Scattering Feature in Be X-ray pulsar GRO J1008-57

35 回旋吸收线及其演化

回旋吸收线来自于强磁场下的电子共振散射。它们在强磁场中子星能谱上呈现出吸收结构，是用来测量中子星磁场大小的最直接手段。回旋线的中心能量不是一成不变的，通常会随着光度、脉冲星自转相位而变化，这反映出了主要辐射区磁场的变化。此外，在某些源中回旋线能量还受到超轨周期调制，或表现出更长时标的演化。在本报告中，我将汇报回旋线研究的近期进展，并展望未来的研究方向。

Speaker: 纪龙 (SYSU)

Slides The evolution of cyclotron resonant scattering features

36 Study on the accretion and radiation process in 1A 0535+26 during the 2020 giant outburst

Through the brightest giant outburst ever of accreting X-ray pulsar 1A 0535+262 in November/December 2020 was observed by Insight-HXMT. We use a method to decompose the pulse profile into the sum of the contribution of the two magnetic poles, constrain the geometry of the pulsar, derive the radiation beam, and study the various characteristics of the radiation beam pattern during the outburst. The beam patterns obtained from the analysis can be interpreted as a combination of the accretion column with halo emission and scattering in the upper accretion stream. The calculation results show that from the beginning to the end of the outburst, the radiation beam patterns will gradually switch from the pencil-beam corresponding to low accretion rate to the fan-beam corresponding to high accretion rate, and back to the pencil-beam pattern at finally, it indicates that the accretion rate changes from low to high and back to low. There are distinct differences in the radiation beam pattern between the rising and fading phases although they have similar luminosity, we suggest that it may be caused by the changes in the position of the accretion disk concerning the pulsar during the outburst process, such as a tilt or shaking.

Speaker: 胡永峰 (Sun Yat-Sen University)

15:15 Break

Session IV

Convener: Chair: 张力

37 eROSITA on SRG: Mapping the Hot Universe

Speaker: A. Merloni

Slides eROSITA on SRG: Mapping the Hot Universe

38 慧眼HXMT对脉冲星的观测进展

慧眼HXMT成功在轨运行5年，已经针对大量致密天体进行了详细观测，在黑洞双星、中子星双星、磁星暴发等方面取得了一系列成果。慧眼也针对三颗年轻脉冲星进行了详细观测，并取得一系列的观测成果，如周期跃变、高精度宽波段的相位分解能谱、制动指数测量等。另外，慧眼高能望远镜的CsI观测数据中也探测到三颗脉冲星的MeV脉冲信号。

Speaker: 葛明玉 (高能所)

Slides 慧眼HXMT脉冲星研究进展

39 Precession of magnetars: dynamical evolutions and modulations on polarized electromagnetic waves

Magnetars are conceived to be highly magnetized neutron stars (NSs). Strong internal magnetic field and elasticity in the crust may deform the star, which lead to the precession of magnetars. We first study the free precession of triaxially-deformed NSs and give the fully analytical solutions. Then we consider the forced precession endowed with electromagnetic torques. The dynamical evolutions of the wobble angle and the magnetic inclination angle are obtained. We apply previous results to study the polarized radio and X-ray emissions that are modulated by precession. For radio signals, we give the timing residuals, the change of pulse width, and the evolutions of the position angle. For X-ray coming from the surface of magnetars, we present the evolution of the Stokes parameters and the spectrum. Our results are ready to be used to search the precession of magnetars with radio and X-ray observations. Observating of precessing magnetars will definitely give us valuable information on the geometry and the strength of the strong magnetic fields, as well as the EoS of NSs.

Speaker: 高勇 (Peking University)

40 Circular Polarization of FRB: Bunching Coherent Curvature Radiation

Coherent curvature radiation as the radiation mechanism for fast radio bursts (FRBs) has been discussed since FRBs were discovered. We study the polarization properties of FRBs. Emitted waves are highly linear polarized and polarization angles are flat across the burst envelopes, if the line of sight is confined to the beam within an angle of 1/γ, while a circular polarization fraction becomes strong for off-beam cases. Different kinds of evolutionary trajectories are found on the Poincaré sphere for the bunch-coherent polarization, and this behavior could be tested through future observations.

Speaker: 王维扬 (PKU)

Slides Circularly Polarized FRB: Bunching Curvature Radiation

41 同步加速辐射的偏振：以GRB 170114A为例

同步加速辐射是高能天体物理研究领域中一种重要的辐射机制。一般认为，同步加速辐射是高线偏振的，如果电子能谱是幂律谱，那么，偏振度仅和电子能谱的谱指数相关。我们深入分析了同步加速辐射的线偏振特性。我们发现，对于不同的电子能谱分布，同步加速辐射的偏振度不仅和电子能谱分布相关，也和辐射频率以及磁场相关。这样，处于不同物理状态的高能天体的同步加速辐射偏振度存在很大的差异。这一理论可以普遍应用于伽马射线暴、X射线双星和耀变体等高能天体的偏振研究中。我们应用这一理论研究详细计算了伽马射线暴瞬时辐射的偏振特性，能够合理解释高能偏振卫星PAOLA对伽马射线暴GRB170114A的偏振观测结果，进一步揭示伽马射线暴中粒子加速和粒子冷却的物理过程。同步加速辐射偏振的理论研究对IXPE、PAOLA2和eXTP等高能偏振卫星的观测也具有重要意义。

Speaker: 毛基荣 (中国科学院云南天文台)

42 Multimessenger signals from transients in AGN accretion disks

In this talk, I will introduce our recent works on the predictions of the multimessenger signals from transients in AGN accretion disks.

Speaker: 朱锦平 (北京大学)

Slides 活动星系核吸积盘中暂现源的多信使辐射

Friday, 17 June

Session I

Convener: Chair: 梁恩维

43 FRB 和引力波电磁对应体

Speaker: 张冰

44 GRB 和磁星

Speaker: 戴子高

45 GRB origins and mechanism

Speaker: 张彬彬

46 Plateau phase in X-ray afterglows of GRBs and application in cosmology

部分伽玛暴的X射线余辉中存在一个缓慢衰减的平台阶段，通常持续数千秒。我们深入研究了平台期的特征物理量之间的相关性，发现发现伽玛暴的各向同性能量Eiso、平台期结束时的X射线辐射光度Lx，以及平台期的结束时间Ta之间存在一个比较紧密的相关关系，称为L-T-E关系。此外，我们进一步还发现谱的峰值能量Ep同Lx、Ta之间也存在一个比较紧密的相关关系，称为L-T-Ep关系。后者在进行红移演化的改正后可作为宇宙学的标准烛光。我们利用该标准烛光限制了Lambda-CDM 和wCDM 宇宙模型中的参数，如暗能量占比和重子物质占比等。我们的研究可为宇宙学研究提供一种新的探针。

Speaker: 黄永锋 (南京大学)

Slides Plateau phase in X-ray afterglows of GRBs and application in cosmology

47 Cosmological probes: standard candles (GRBs) and standard sirens (GWs)

In this talk, I will present recent progress on GRB cosmology firstly. Then, the cosmological applications of GWs with EM counterparts are discussed.

Speaker: 王发印 (Nanjing University)

10:30 Break

Session II

Convener: Chair: 徐仁新

48 Results from the Gamma-Ray Bursts polarimeter POLAR and future prospects with the POLAR-2 mission

Since the discovery of Gamma-Ray Bursts (GRBs), these violent transient events in the Universe are among the hottest astronomy topics, followed by many outstanding observations and theoretical interpretations. However, many open questions remain or are even newly raised about their nature, especially the physical mechanisms during their prompt emission phase, although more than half a century has past. The polarization properties have long been thought to be a powerful probe for investigating the radiation mechanisms of the prompt emission, as well as the geometrical structure and magnetic field configurations of the radiation region. Fortunately, newly developed polarimeters in recent years have overcome the space technical difficulties on polarization measurements, which opens a new window for space hard X-ray/Gamma-ray polarimetry. The Gamma-Ray Burst polarimeter POLAR, which has been launched onboard the China’s space lab “Tiangong-2” in September 2016, is a space mission dedicated for the GRB prompt emission polarization measurements in the 50-500 keV energy range, under the collaboration between Chinese and European scientists. During about 6 months of space observation, POLAR detected 55 confirmed GRBs jointly with other missions and some potential individual GRBs by itself. A polarization catalog of 14 GRBs in total has been published from POLAR in-orbit data, which is the best GRB polarization measurement results so far thanks to the high sensitivity and large field of view of the instrument, as well as the precisely calibrated systematic errors for polarization measurements. The results show that the detected GRBs are at most modestly polarized. Another new finding of the evolution of the intrapulse polarization angle provides us with a new insight into the GRB physics. POLAR results raised large interests as well as several critical scientific questions regarding GRB physics. Furthermore, the scientific potentials of POLAR have been extended during the flight which enabled the instrument to detect the Crab pulsar for navigation test studies, phase-resolved spectrometry and even polarization measurements. Currently, the POLAR data analysis is still ongoing for several research interests. The POLAR-2 mission, which is the successor of POLAR, has been accepted to be installed onboard the China Space Station experimental module dedicated to answering the questions raised by POLAR results under an enlarged China-Europe collaboration. With an improved instrument design, POLAR-2 will be able to provide a much larger sample of GRB polarization measurements with high quality and detailed polarization measurements specified as time-resolved and energy-resolved polarization analysis, thanks to the large and efficient polarimeters, and also the spectrometers which are planned to be equipped. Besides, several pulsars are expected to be seen by POLAR-2 and more stringent constraints are foreseen on the Crab pulsar polarization measurements. Currently, the POLAR-2 instruments are under development with the aim of launching date around 2025. In this talk we will mainly present an overview of the POLAR results and the prospects and progress of the POLAR-2 mission.

Speaker: 孙建超 (Institute of High Energy Physics, Chinese Academy of Sciences)

49 FRB观测和证认研究

Speaker: 林琳

50 SGR/FRB 射电和X射线辐射区限制

Speaker: 张镇

11:45 Lunch

Session III

Convener: Chair: 方陶陶

51 活动星系核的X射线冕区辐射

活动星系核的强X射线辐射据信来自于核区的高温冕区，虽然经历几十年的观测，人们仍然对AGN的冕区缺乏清晰的认识。NuSTAR X射线卫星在3-78 keV能段直接成像观测，可以准确测量活动星系核的冕区温度。利用NuSTAR的高质量光谱， 我们在非Blazar射电躁AGN的NuSTAR光谱中普遍探测到了高能截断特征，表征了其X射线辐射与射电宁静AGN类似，都来源于高温冕区。进一步，我们惊讶地发现，与常规猜测相反，AGN冕区温度与X射线光谱指数呈正相关。同样令人惊讶的是，因为射电躁AGN具有更平的X射线光谱，其冕区温度比射电宁静AGN更低。我们在AGN个源中也发现了随着光谱变陡冕区温度升高的趋势（这一关系可能在谱指数大于2时反转）。这些发现对理解冕区物理提供了全新的线索。

Speaker: 王俊贤 (USTC)

Slides 活动星系核的X射线冕区辐射

52 X-ray high-energy astrophysics: an overview of personal research

In this talk, I will present a brief overview of my research on X-ray high-energy astrophysics, including X-ray binaries, AGNs, X-ray surveys, X-ray transients, etc., to pay a tribute to the 60th anniversary of X-ray astronomy.

Speaker: 薛永泉 (University of Science and Technology of China)

Slides X射线高能天体物理的观测研究：个人研究回顾

53 X-ray spectral and timing study of super-Eddington AGN

AGN exhibit the most powerful accretion and radiation processes in the Universe. Super-Eddington Narrow-line Seyfert 1 Galaxies (NLS1s) are phenomenal because of their small black hole masses and very high mass accretion rates. In this talk, I will first talk about the general properties of super-Eddington NLS1s, mainly focusing on the X-ray spectral-timing properties and broadband SED. These observational results can help us to constrain the super-Eddington disc structure, which contains a standard outer disc, a puffed-up inner disc with strong disc wind and advection, an extended soft X-ray corona, and a compact hard X-ray corona. We can also obtain reliable measurements of the global radiation efficiency. In the second part, I will present latest results about an enigmatic, extreme super-Eddington NLS1 RX J0134.2-4258, and compare it with super-Eddington quasars at high redshifts.

Speaker: 金驰川 (NAOC)

54 The diffuse X-ray emission in M51

Speaker: 纪丽

Slides The Diffuse X-ray Emission in M51

55 Discovery and Follow-ups of an Unprecedented SMBH Binary Candidate Predicted to Merge within Three Years

We have recently discovered the first ever SMBH binary candidate approaching final coalescence in a nearby Seyfert 1 galaxy at redshift 0.08. The discovery was made by its unprecedented chirping flares, which predicts a merger time within three years according to our trajectory model (Jiang et al. 2022, arxiv:2201.11633). Since its discovery, extensive multi-wavelength follow-up observations have been conducted, including massive X-ray observations by Swift, XMM-Newton, NuSTAR, Chandra and NICER. We will introduce the discovery and latest observational progresses on the unique system.

Speaker: 蒋凝 (USTC)

Slides Discovery and Follow-ups of a SMBH binary candidate predicted to merge within three years

15:25 Break

Session IV

Convener: Chair: 袁为民

56 Recent developments in tidal disruption events theory

A tidal disruption event happens when a star wanders too close to the massive black hole in the center of a galaxy and gets tidally disrupted. The collision and accretion of the stellar debris powers a bright, transient flare. Tidal disruption events provide a unique opportunity to probe quiescent massive black holes and stellar dynamics in centers of distant galaxies, as well as to study the physics of black hole accretion and ejection.  In this talk, I will review our current theoretical understanding of tidal disruption events, and pose some outstanding questions when comparing theory to observations. I will also discuss the prospect of using tidal disruption events to probe the demographics of massive black holes in the coming years, as various surveys such as the Vera Rubin Observatory and Einstein Probe Telescope will allow us to obtain a large sample of such events.

Speaker: Lixin Dai (The University of Hong Kong)

Slides Recent Developments in Tidal Disruption Events Theory (and Observations)

57 The accretion disk and X-ray radiation in TDE

Speaker: 刘富坤

58 Two tales of X-ray QPEs and the discovery of a Compton echo in TDE

X-ray quasi-periodic eruptions (QPEs) are a recently discovered phenomenon associated with supermassive black holes at the centers of galaxies. They are high-amplitude soft X-ray flares that recur on timescales of hours, but what causes these flares remains uncertain. In this talk, I will review the history in discovering the QPE phenomenon and its possible origins, especially the difference between QPEs claimed in literature. In addition, I will report the discovery of a long-lasting Compton echo in a TDE candidate, which allows for constraining the distribution and physical conditions of circumnuclear gas, such as those in torus.

Speaker: 舒新文 (Anhui Normal University)

Slides Two tales of X-ray QPEs

59 Highly Variable X-ray Sources and Tidal Disruption Events in the XMM-Newton SLew survey

By comparing with the fluxes (and upper limits) given in RASS, we have constructed a highly variable source sample, comprising 265 sources (2.5 per cent) selected from the XMMSL2 clean catalogue. These source displayed X-ray variability of a factor of more than 10 in 0.2--2\,keV compared to the RASS. Of the sample sources, 94.3 per cent are identified. The identification procedure follows a series of cross-matches with astronomical data bases and multiwavelength catalogues to refine the source position and identify counterparts to the X-ray sources. Assignment of source type utilizes a combination of indicators including counterparts offset, parallax measurement, spectral colours, X-ray luminosity, and light-curve behaviour. We identified 40 per cent of the variables with stars, 10 per cent with accreting binaries, and at least 30.4 per cent with active galactic nuclei. The rest of the variables are identified as galaxies. It is found that the mean effective temperatures of the highly variable stars are lower than those of less variable stars. Our sample of highly variable AGN tend to have lower black hole masses, redshifts, and marginally lower soft X-ray luminosities compared to the less variable ones, while no difference was found in the Eddington ratio distributions. Five flaring events are tidal disruption events published previously. This study has significantly increased the number of variable sources in XMMSL2 with identifications and provides greater insight on the nature of many of the sources, enabling further studies of highly variable X-ray sources. We have also found several special variable sources, including highly variable AGNs and TDE candidate, and have conducted a detailed analysis for one of TDE candidate(XMMSL1\,J1319+2259). Multiwavelength analysis shows that this TDE belongs to a rare sample with contemporaneous bright emission detected in the X-ray, UV, and optical, which are later echoed by dust-reprocessed light in the mid-infrared. The black hole has a mass of ~5$\times 10^7 M_{\odot}$ residing in a galaxy that is dominated by a middle-aged stellar population of 2.5\,Gyr. The XMMSL2 variable source sample have been published in MNRAS, and the TDE paper has been published in ApJ.

Speaker: 李东悦 (NAOC)

Slides Highly Variable X-ray Sources and Tidal Disruption Events in the XMM-Newton SLew survey (XMMSL)

60 Discovery of ATLAS17jrp as an Optical, X-ray and Infrared Bright TDE in a Star-forming Galaxy

We hereby report the discovery of ATLAS17jrp as an extraordinary TDE in star-forming galaxy SDSSJ162034.99+240726.5 in our recent sample of mid-infrared outbursts in nearby galaxies. Its optical/UV light curves rise to a peak luminosity $\sim1.06\times10^{44}\rm\,erg\,s^{-1}$ in about a month and then decay as $\rm t^{-5/3}$ with a roughly constant temperature around 19000~K, and the optical spectra show a blue continuum and very broad Balmer lines with FWHM$\sim$15000 km/s which gradually narrowed to 1400 km/s within 4 years, all agreeing well with other optical TDEs. A delayed and rapidly rising X-ray flare with a peak luminosity $\rm \sim 1.27\times10^{43}\,erg\,s^{-1}$ was detected at $\rm \sim$ 170 days after the optical peak. The high MIR luminosity of ATLAS17jrp ($\sim2\times10^{43} \rm\,erg\,s^{-1}$) has revealed a distinctive dusty environment with covering factor as high as $\sim0.2$, that is comparable with that of torus in active galactic nuclei but at least one order of magnitude higher than normal optical TDEs. Therefore, ATLAS17jrp turns out to be one of the rare unambiguous TDE found in star-forming galaxies and its high dust covering factor implies that the dust extinction could play an important role in the absence of optical TDEs in star-forming galaxies.

Speaker: 王义博 (USTC)

Slides Discovery of ATLAS17jrp as an optical, infrared, and X-ray bright TDE

61 Searching for Quasi-periodic Oscillations in Active Galactic Nuclei of the Chandra Deep Field South

Recent X-ray observations have revealed growing evidence of quasi-periodic oscillation (QPO) in the light curve of active galactic nuclei (AGNs), which may serve as a useful probe of black hole physics. In this work, we present a systematic search for X-ray QPOs among $\sim$ 1000 AGNs of the Chandra Deep Field South (CDF-S) in a homogeneous fashion. Dividing the 7-Ms Chandra observations into four epochs, we search for periodic signals that are persistent throughout any of these epochs, using two independent methods: Lomb-Scargle periodogram and Gregory-Loredo Algorithm. No statistically significant periodic signal is found with either method on any of the four epochs. Our extensive simulations of source light curves suggest that this non-detection is primarily due to a moderate sensitivity of the CDF-S data in QPO detection. Using the simulation-predicted detection efficiency, we are able to provide a meaningful constraint on the intrinsic occurrence rate of persistent QPOs, $ < (15-20)\%$, provided that they share a similar power spectral density with a handful of currently known AGN QPOs. The true intrinsic occurrence rate might be significantly below this upper limit, however, given the non-detection among the CDF-S sources. Our additional search for short-lived QPOs that are only detected over a small subset of all observations results in two candidates, one in source XID 643 at a period of $\sim$ 13273 s and the other in source XID 876 at a period of $\sim$ 7065 s.

Speaker: 鲍通 (Nanjing University)

Slides Searching for Quasi-periodic Oscillations in Active Galactic Nuclei of the Chandra Deep Field South

Saturday, 18 June

Session I

Convener: Chair: 熊少林

62 深度探索极端宇宙：eXTP, HERD & POLAR-2

Speaker: 张双南

63 国内X射线Wolter-I聚焦望远镜研制进展

Speaker: 陈勇

Slides X射线Wolter-I 聚焦望远镜研制进展研制进展

64 The Lobster Eye Optics for WXT on board EP mission

Speaker: 张臣

65 科学级CMOS探测器研究进展

近年来随着半导体工业的高速进步，科学级CMOS图像传感器性能有了巨大的提升。实验室自2015年开始对科学级CMOS探测器的性能开展了研究，并对空间X射线天文应用进行了实验验证。在读出速度，制冷温度，抗辐照性能和成本方面CMOS探测器比传统的CCD型探测器有着明显的优势。2019年定制开发了6cm×6cm大面阵CMOS探测器并获得成功流片。性能达到读出帧频20Hz，能量分辨率210eV@5.9keV。自研的读出相机已经可实现在-30度下20Hz图像的实时输出和X射线事例提取。

Speaker: 凌志兴 (NAOC)

66 国内X射线天文探测器的发展现状

随着我国X射线天文学研究进入时域与多信使天文学时代，我国的空间X射线天文探测项目正处于大发展时期。与此同时，我国的X射线探测器发展也取得了显著的成就。本报告将针对国内X射线探测器在空间X射线探测项目中的成功应用进行总结，对国内X射线探测器在若干方向上的最新发展和潜在的应用方向进行介绍和简单的评述。

Speaker: 姜维春 (高能所)

10:30 Break

Session II

Convener: Chair: 徐玉朋

67 “全变源追踪猎人星座”计划（CATCH）介绍及最新进展

时域天文学是现代天文学的一个重大前沿方向，针对时域天文学领域后随观测能力的严重不足，中科院高能物理研究所于2019年在国际上创新性地提出了一个空间探测计划，“全变源追踪猎人星座”计划（Chasing All Transients Constellation Hunters，简称CATCH）。CATCH将由4种类型的百颗微型卫星组成X射线观测星座，其核心科学目标为“刻画极端宇宙多维动态全景”。每颗卫星上都将配置我国自主研发的、具有聚焦成像能力的紧凑型轻量化X射线望远镜。不同卫星将通过智能化控制系统实现最优化协同配合，对海量变源天体开展全天区、多目标、多维度（时间维度—时变、空间维度—成像、能量维度—能谱、磁场几何维度—偏振）同时后随观测。CATCH具有前所未有的科学能力，将带来重要的科学发现，是一个变革性的空间探测计划。在此报告中，我将介绍CATCH的整体规划和最新研制进展。

Speaker: 陶炼 (高能所)

68 脉冲星导航进展及未来发展的思考

本报告将梳理脉冲星导航近年来在理论研究、探测技术及在轨验证等方面的进展情况，提出其未来发展的一些思考。

Speaker: 郑世界 (高能所)

Slides 脉冲星应用进展与未来发展的思考

69 X射线暂现源大视场偏振巡天探测器技术和POLAR2/LPD研制进展

Speaker: 刘宏邦

Slides X射线暂现源大视场偏振巡天探测器技术和POLAR2/LPD研制进展

70 IXPE卫星对脉冲星风云的偏振观测

Speaker: 谢斐

71 中国下一代空间高能多波段观测天文台

2017年6月15日发射的慧眼卫星，揭开了我国空间宽谱段X/γ射线探测的序幕，本项目将覆盖近红外至紫外（0.16~2.2μm）波段、3keV~3GeV能段，通过先进的宽谱段能谱、成像以及偏振等综合观测，来综合研究处于致密天体附近极端物理条件下的极端物理规律、宇宙线的加速机制以及极端宇宙环境中元素核合成过程等科学问题。

Speaker: 张龙 (å)

12:05 Lunch

Session III

Convener: Chair: 吴雪峰

72 Transient Science with FAST

Speaker: 李菂

Slides Transient Science with FAST

73 LHAASO

Speaker: 曹臻

Slides LHAASO——开启超高能γ-天文学及后续发展

74 Neutrino astronomy: status and prospects

Speaker: 徐东莲

75 X-ray Astronomy and beyond: research milestones and recent progress of SHAO/OHEA group

Based on research experience in observatinal high energy astrophsyics achieved in IHEP since ~ 30 years ago, SHAO/OHEA group has made significant progress in observational X-ray astronomy and relativistic astrophysics, and has developed strong expertise in multi-wavelength observations largely competent in time-domain astronomy. Here I will give a brief overview of the milestones of our achievements in the past decade, and present recent achievements in ground observations (radio/optical astronomy) and space observations (optical/UV/X-ray/hard X-ray), including both wide field-of-view monitoring and dedicated multi-wavelength follow-up observations of diverse relativistic transients of importance in the ero of time-domain astronomy (such as black hole transients, tidal disruption events, and fast radio bursts, etc.).

Speaker: 余文飞 (Shanghai Astronomical Observatory)

76 Prospects of detecting supernova shock breakouts, TDE and GW EM counterparts with the Einstein Probe

The Einstein Probe (EP) is a small mission dedicated to time-domain astronomy in the soft X-ray band. Its primary scientific goals are concerned with discovering transients of particular interest, including tidal disruption events (TDEs), supernova shock breakouts (SN SBOs), and electromagnetic counterparts of gravitational wave (GW) events. In this report, on behalf of the EP team, I will give an introduction on the prospects of detecting these transients with the EP, including observation strategies and forecast of the detection rate.

Speaker: 刘禾阳 (国家天文台)

Slides Prospects of detecting supernova shock breakouts, TDE, and GW EM counterparts with the Einstein Probe

77 Searching for astrophysical neutrino counterparts

Pinpointing the neutrino sources is crucial to unveil the mystery of high-energy cosmic rays. The possible association of the neutrino alert IceCube-170922A with the flaring blazar TXS0506+056 marks the new era of neutrino astronomy. Tracking the sources close to the IceCube high-energy alerts is an efficient way to search for neutrino-source candidates. We have been following up on the neutrino alerts with the insight-HXMT twice. The upper limits from potential neutrino sources are obtained. Additionally, we have performed several analyses to search for potential neutrino emissions from multi-frequency catalogs and various blazar samples, investigating possible correlations with IceCube alerts and 10-year track-like events. No significant neutrino emissions were found in our analyses. Our results indicate an interesting trend showing the infrared flaring stages of WISE blazars might be correlated with the arrival times of the neutrino alerts. Possible overflow of neutrinos associated with two of our blazar sub-samples are also illustrated. One is characterized by a significant flaring lag in infrared with respect to gamma-rays, as seen for TXS0506+056, and highly simultaneous infrared and gamma-ray flares characterize the other. These phenomena suggest the need to improve current multi-frequency light-curve catalogs to pair with the advent of more sensitive neutrino observatories.

Speaker: 张淯翎 (TDLI)

Discussion

讨论：X射线望远镜如何更加有效地与其他多波段、多信使观测设备开展高效的天地联合观测，共同研究X射线双星、磁星、脉冲星、引力波暴、伽马射线暴、快速射电暴等动态天文事件，全面打开“动态宇宙的新窗口”？
X射线天文学在时域与多信使天文学时代要迎接哪些挑战？如何进一步推进并且拓展我国提出并主导的“探索极端宇宙”国际大科学计划？如何通过X射线以及相关的多信使天文观测检验并且发展基本物理规律？

Convener: Chair: 卢方军

78 总结