Constraints on Dark Energy from the CSST Galaxy Clusters

We study the potential of the galaxy cluster sample expected from the Chinese Space Station Telescope(CSST)survey to constrain dark energy properties.By modeling the distribution of observed cluster mass for a given true mass to be log-normal and adopting a selection threshold in the observed mass M_200m≥0.836×10¹⁴ h^-1 M_⊙,we find about 4.1×10⁵ clusters in the redshift range 0≤z≤1.5 can be detected by the CSST.We construct the Fisher matrix fo...     

Orbital period correction and light curve modeling of the W-subtype shallow contact binary OW Leo

Orbital period and multi-color light curves’investigation of OW Leo are presented for the first time.The orbital period of OW Leo is corrected from P=0.325545 days to P=0.32554052 days in our work,and the observational data from the All-Sky Automated Survey for Super Novae(ASAS-SN)are used to test the newly determined orbital period.Then,the phased light curves are calculated with the new period and the Wilson-Devinney program is applied to model the light curves,which reveal that OW Leo is a W-subtype shallow contact binary system(q=3.05,f=12.8%).The absolute physical parameters of the two component stars are estimated to be M₁=0.31(1)M_⊙,M₂=0.95(3)M_⊙,R₁=0.63(1)R⊙,R₂=1.04(1)R_⊙,L₁=0.43(1)L_⊙and L₂=1.01(2)L_⊙.The evolutionary status shows that the more massive star is less evolved than the less massive star.OW Leo has very low metal abundance,which means its formation and evolution are hardly influenced by any additional component.It is formed from an initially detached binary system through nuclear evolution and angular momentum loss via magnetic braking,and has passed a very long time of main sequence evolution.     

GRS 1915+105的X射线能谱分析及黑洞自旋测量

GRS 1915+105是银河系内的低质量黑洞X射线双星,其能谱和黑洞自旋已经得到了广泛的研究.自2018年6月开始,其X射线流量下降到了低流量水平,其间偶尔会产生多波段的耀发.利用Insight-HXMT(Insight-Hard X-ray Modulation Telescope,简称为慧眼)卫星在2020年8月30日到2020年10月13日之间对GRS1915+105的观测数据,研究了其能谱特性,发现在此次爆发过程中, X射线能谱可以用一个康普顿化的多温黑体谱很好地拟合.整个爆发的硬度强度图(Hardness-Intensity Diagram, HID)一直处于软态.采用GRS1915+105的最新动力学参数M=12.4_-1.8^+2.0M⊙, i=60°±5°, D=8.6_-1.6^+2.0kpc (M、M⊙、i和D分别表示黑洞质量、太阳质量、盘倾角和距离),得到其无量纲黑洞自旋a*的一个下限a*> 0.9990,确认了GRS 1915+105是一个具有极端自旋的黑洞.考虑本地吸收体的...     

The Unusual AGN Host NGC 1266: Evidence for Shocks in a Molecular Gas Rich S0 Galaxy with a Low Luminosity Nucleus

NGC 1266 is a lenticular galaxy(S0) hosting an active galactic nucleus(AGN), and known to contain a large amount of shocked gas. We compare the luminosity ratio of mid-J CO lines to IR continuum with star-forming galaxies(SFGs), and then model the CO spectral line energy distribution(SLED). We confirm that in the mid-and high-J regions(J_up= 4–13), the C-type shock(v_s= 25 km s^-1, n_H= 5 × 10⁴cm^-3) can reproduce the CO observations w...     

耀变体亮温度与黑洞喷流能量的相关性讨论

耀变体(Blazars)的亮温度与黑洞喷流能量和吸积率有重要关系.搜集了53个耀变体源样本,包括22个蝎虎天体(BL Lacs)和31个平谱射电类星体(Flat Spectrum Radio Quasars,FSRQs),研究了耀变体亮温度与黑洞喷流能量的分布,并对子类中亮温度与黑洞喷流能量的相关性进行了讨论.研究结果...     

Fermi耀变体的辐射特性和演化研究

搜集和计算了734个Fermi耀变体样本,包括322个蝎虎天体(其中148个高峰频蝎虎天体、73个中峰频蝎虎天体以及101个低峰频蝎虎天体)和412个平谱射电类星体(其中18个高峰频平谱射电类星体、45个中峰频平谱射电类星体以及349个低峰频平谱射电类星体)。研究了每个子类的红移分布、黑洞质量分布以及γ射线光度的分布,并对其红移、黑洞质量、γ射线光度以及同步峰值频率的相关性进行了分析,结果表明:(1)根据红移与γ射线光度分别从高到低的排序,得到Fermi耀变体的演化序列遵循平谱射电类星体→蝎虎天体,且高同步峰频耀变体→中同步峰频耀变体→低同步峰频耀变体,但根据黑洞质量从高到低得到的演化序列不同,这可能是黑洞质量的估计误差以及黑洞质量样本数量较少造成的;(2)Fermi耀变体每个子类的红移与黑洞质量、黑洞质量与γ射线光度之间正相关;(3)Fermi耀变体每个子类的红移、γ射线光度分别与同步峰频之间反相关,黑洞质量与同步峰频之间不存在相关性。     

观测证据对小质量AGB星13C中子源的约束

¹³C(α,n)¹⁶O反应是小质量渐近巨星分支(asymptotic giant branch,AGB)星(M/M_⊙≤3,M和M_⊙分别表示AGB星的质量和太阳质量)内s过程(慢中子俘获过程)的主要中子源。在对流热脉冲间隔期间,一个储层(即所谓的“¹³C袋”)内的¹³C在辐射条件下(约8 keV)燃烧并释放中子。到目前为止,¹³C袋的物理形成过程仍远未被充分理解,因此¹³C袋的结构也一直无法被完全确定。在后处理核合成计算中,¹³C袋通常是利用观测数据通过自由的参数化来约束。从基本原理、主要效果及局限性等方面综述了不同观测证据对¹³C袋的约束作用,最后展望了¹³C中子源约束问题未来可能的研究方向。     

国家授时中心40米射电望远镜Crab脉冲星周期跃变监测

脉冲星周期跃变是一种罕见的现象,是研究其内部结构的探针。针对2019年2月~12月国家授时中心昊平观测站40 m射电望远镜在脉冲星计时观测中监测Crab脉冲星的数据,采用脉冲星计时方法,用TEMPO2拟合程序进行分析。结果表明,Crab脉冲星在2019年7月23日(MJD 58687)附近发生了一次周期跃变现象,该跃变自转增量为Δv_g=5.33(4)×10^-7Hz,自转变化量为Δv_g/v=17.9(1)×10^-9,并伴随着恢复系数Q~0.88的指数恢复过程。此次Crab脉冲星周期跃变的监测及处理,证实了40 m射电望远镜对脉冲星的监测性能,同时为研究周期跃变的产生机理积累了样本。     

Photometric Investigation of Contact Binary DY Cet Based on TESS Data

We present a photometric analysis of the Transiting Exoplanet Survey Satellite(TESS) light curve of contact binary system DY Cet and the behavior of its orbital period variation.The light curve and published radial velocity data analysis was performed using the Wilson-Devinney code.As a result of simultaneous analysis of the light curve with radial velocity data,the masses and radii of the system’s components were determined as M₁=1.55±0.02 M_⊙,M₂=0.55 ± 0.01 M_⊙ and R_...     

A Machine Learning Made Catalog of FR-Ⅱ Radio Galaxies from the FIRST Survey

We present an independent catalog (FRIIRGcat) of 45,241 Fanaroff–Riley Type Ⅱ (FR-Ⅱ) radio galaxies compiled from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey and employed the deep learning method.Among them,optical and/or infrared counterparts are identified for 41,425 FR-Ⅱs.This catalog spans luminosities 2.63×10²²≤L_rad≤6.76×10²⁹W Hz^-1and redshifts up to z=5.01.The spectroscopic classification indicates that...     

长周期彗星动力学特性统计研究

基于JPL (Jet Propulsion Laboratory)和MPC (Minor Planet Center)的彗星观测数据, 对长周期彗星(Long Period Comet, LPC)的轨道进行逆向演化, 得到其原始轨道, 并分析了LPC的观测轨道和原始轨道的动力学特性. 研究表明: LPC观测轨道半长轴倒数(1/a)_obs和原始轨道半长轴倒数(1/a)_ori分布存在显著差异, 峰值分别位于(1/a)_obs～ 2 × 10^-5au^-1和(1/a)_ori～ 6 × 10^-5au^-1; 大近日点LPC(近日点距离q > 3.1 au)和小近日点LPC (近日点距离q 3.1 au)的原始轨道(1/a)_ori峰值位置相同, 均位于1 × 10^-4au^-1; JPL和MPC数据中LPC的原始轨道(1/a)_obs峰...     

The Study of the Physical Properties and Energy Sources of Five Luminous Type Ibc Supernovae

In this paper,we study five luminous supernovae(LSNe) Ibc(SN 2009ca,ASASSN-15mj,SN 2019omd,SN 2002ued,and SN 2021bmf) whose peak absolute magnitudes M_peak are ≈-19.5 to-21 mag by fitting their multi-band light curves(LCs) with different energy source models.We find that SN 2009ca might be powered by the ⁵⁶Ni model since the required ⁵⁶Ni mass(0.56 M_⊙) is comparable to those of energetic SNe Ic,while the rest four SNe cannot be accounted for the ^56...     

GRB 130310A: very high peak energy and thermal emission

The special GRB 130310 A was observed by Fermi Gamma-Ray Burst Monitor and Large Area Telescope,with T90~2.4 s.With a combination of a Band function and a blackbody(BB)function,the time-resolved spectral analysis of GRB 130310 A confirmed that there is a sub-dominate thermal component in the early period(e.g.,slice T0+[4.03-4.14]s)spectrum with BB temperature(kT)being~7~5 keV,which can be interpreted as photosphere emission.The precursor of GRB 130310 A can be fitted well with a BB component with kT~45 keV,which is higher than that of the main burst.It suggests that the radiation of GRB 130310 A is in transition from thermal to non-thermal.Such a transition is an indication of the change in jet composition from a fireball to a Poynting-flux-dominated jet.A very high peak energy is obtained in the first time bin,with the peak energy E_p of the Band component for Band+BB and Band model being~8.5~5.2 MeV and~11.1~7.4 MeV,respectively.Afterwards,the E_p drops to~1 MeV.The E_p evolution patterns with respect to the pulses in the GRB 130310 A light curves show a hard-to-soft evolution.The interpretation of the high peak energy E_p within the photosphere and internal shock model is difficult.It also suggests that at least for some bursts,the Band component must invoke a non-thermal origin in the optically thin region of a GRB outflow.Assuming the redshift is z~0.1~8,the radius of the jet base r₀~10⁹ cm to allow(1+σ₁₅)>1 in line with the calculation results of the magnetization parameter at~1015 cm(σ₁₅).However,the value of(1+σ₁₅)is■1 in the zone z around 3 for r₀~10⁹ cm,suggesting the non-excluded possibility that the origin is from ICMART with a low value.The photosphere-internal shock seems capable of interpreting the high peak energy,which requires electron Lorentz factorγe~60 andεe~0.06.     

球状星团中大质量黑洞附近的密度分布

(一)前言 近年来,实测和理论工作都转向了探索大质量的黑洞(10~M⊙～10~9M⊙),众所周知的NGC6624和M87的观测表明,在它们中心可能存在一个大质量的黑洞,为了定量地解释这些观测事实,必须首先求出它们核心附近星的密度分布Peebles和J.N.Bahcall等人从牛顿力学出发,并假定分布函数为f=CE~2的情况下分别得出了n(r)～(r/r_a)~(-9/4)(对应α=3/4)和n(r)～(r/y_a)~(-7/4)(对应α=1/4),他们的工作有两点不     

蝎虎天体PKS 0735+178的光变特性分析

在收集大量数据的基础上,用时间补偿离散傅里叶变换法、Jurkevich方法和离散相关分析法分析了PKS 0735+178的B波段和V波段光变周期,发现该天体具有(4.33±0.41)年的光变周期,其中心黑洞质量的下限为0.22×10~6M_⊙。     

天秤座EH光变周期变化新探

我们于1980年5月18、19日及6月15日和1981年1月15日四夜,用高速光电光度计观测了天秤座EHLib,获得6个光度极大时刻。与前人的观测资料综合分析,得出该星的观测极大时刻与计算极大时刻间的差值(O—C)随周期数E的变化,可以定性地表示为其中T_o=H.J.D.2433438.6088,P_o=0.0884132445天,β6.0×10~(-13)天/周-2.4×10~(-9)天/年-2.8×10~(-8)/年,A0.0015天,E_o70700P_o6250天17.1年。假如用双星系统的光时效应来解释其中的正弦项,则双星系统轨道的半长径α近似为0.28天文单位,轨道视向速度峰值投影K=(2παsini)/(E_o)0.45km/s,质量函数f(m)6×10~(-5)M_☉。     

平谱射电类星体3C 454.3中长周期有效谱指数特性研究

耀变体是一种非常活跃的活动星系核,研究它的有效谱指数是认识其内部结构和辐射机制的有效方法。文中数据来源于目前已公布的SMARTS(Small and Medium Aperture Research Telescope System)数据库,共682组具有B, V, R, J和K波段的准同时性的观测数据,用LSP(LombScargle Periodogram)方法研究了其有效谱指数的特性,研究结果表明,3C 454.3光学和红外波段光变之间呈正相关;光学和红外波段光变存在两个主导周期,分别约为1.2年和4.5年;双黑洞结构模型中双黑洞质量比约为2∶1。     

New photometric investigation of the low-mass-ratio contact binary star V1853 Orionis

Four-color charge-coupled device(CCD) light curves in the B, V, Rc and I c bands of the totaleclipsing binary system V1853 Orionis(V1853 Ori) are presented. By comparing our light curves with those published by previous investigators, it is determined that the O'Connell effect on the light curves has disappeared. By analyzing those multi-color light curves with the Wilson-Devinney code(W-D code),it is discovered that V1853 Ori is an A-type intermediate-contact binary with a degree of contact factor of f = 33.3%(3.7%) and a mass ratio of q = 0.1896(0.0013). Combining our 10 newly determined times of light minima together with others published in the literature, the period changes of the system are investigated. We found that the general trend of the observed minus calculated(O-C) curve shows a downward parabolic variation that corresponds to a long-term decrease in the orbital period with a rate of d P/dt =-1.96(0.46)×10^-7 d yr^-1. The long-term period decrease could be explained by mass transfer from the more-massive component to the less-massive one. By combining our photometric solutions with data from Gaia DR_2, absolute parameters were derived as M_1 = 1.20 M⊙, M_2 = 0.23 M⊙, R_1 = 1.36 R⊙and R_2 = 0.66 R⊙. The long-term period decrease and intermediate-contact configuration suggest that V1853 Ori will evolve into a high fill-out overcontact binary.     

A broad absorption line outflow associated with the broad emission line region in the quasar SDSS J075133.35+134548.3

We report on the discovery of unusual broad absorption lines(BALs)in the bright quasar SDSS J075133.35+134548.3 at z~1,using archival and newly obtained optical and NIR spectroscopic data.The BALs are detected reliably in HeⅠ*λ3889,HeⅠ*λ10830 and tentatively in AlⅢ,MgⅡ.These BALs show complex velocity structures consisting of two major components:a high-velocity component(HV),with a blueshifted velocity range ofΔv_HV~9300--3500 km s^-1,which can be reliably detected in HeⅠ*λ10830,and tentatively in AlⅢand MgⅡ,whereas it is undetectable in HeⅠ*λ3889;and a low-velocity component(LV),withΔv_LV~3500--1800 km s^-1,is only detected in HeⅠ*λ3889 and HeⅠ*λ10830.With the BALs from different ions,the HV outflowing gas can be constrained to have a density of nH~10^10.3-10^11.4 cm^-3,a column density of NH~10²¹ cm^-2and an ionization parameter of U~10^-1.83-10^-1.72;inferring a distance of RHV~0.5 pc from the central continuum source with a monochromatic luminosityλLλ(5100)=7.0×10⁴⁵erg s^-1at 5100 A.This distance is remarkably similar to that of the normal broad line region(BLR)estimated from reverberation experiments,suggesting association of the BLR and the HV BAL outflowing gas.Interestingly,a blueshifted component is also detected in AlⅢand MgⅡbroad emission lines(BELs),and the AlⅢ/MgⅡof such a BEL component can be reproduced by the physical parameters inferred from the HV BAL gas.The LV BAL gas likely has a larger column density,a higher ionization level and hence a smaller distance than the HV BAL gas.Further spectroscopy with a high S/N ratio and broader wavelength coverage is needed to confirm this to shed new light on the possible connection between BALs and BELs.     

The conformity of HI galaxies in ALFALFA-SDSS sample

The conformity effect,indicating the evolution of galaxies is related to its surrounding neighbor galaxies as far as a few Mpc,is an interesting phenomenon in the modeling of galaxy and evolution.Here we study the conformity effect of HI galaxies in a matched galaxy sample between SDSS DR7 and ALFALFA surveys.By checking the probability difference for the detected H i galaxies as a function of distance around a normal or an H i galaxy,we find that this effect is significant out to 5 Mpc.It also shows a dependence on the stellar mass of galaxies,with the strength the strongest in the stellar mass range of 10¹⁰*/M_⊙<10^10.5.However,when the sample is confined to central galaxies in groups with virial radii smaller than 1 Mpc,the 1-halo conformity signal is still evident,while the 2-halo conformity signal is reduced to a very weak amplitude.Our results confirm the previous study in the optical band that the 2-halo term is possibly caused by the bias effect in the sample selection.Furthermore,we confirm the existence of the 1-halo conformity discovered in the optical and radio band in previous investigations.Our results provide another viewpoint on the conformity effect and hope to shed light on the co-evolution of the galaxies and their neighbors in the current galaxy formation models.