We report the results of Swift/XRT observations (2008-2015) of a hyper-luminous X-ray source, ESO 243-49 HLX-1. We found a strong observational evidence that ESO 243-49 HLX-1 underwent spectral transitions from the low/hard state to the high/soft state during these observations. The spectra of ESO 243-49 HLX-1 are well fitted by the so-{called} bulk motion Comptonization model for all spectral states. We have established the photon index Gamma saturation level, Gamma_{sat}$=3.0+/-0.1, in the correlation of Gamma versus mass accretion rate dot M. This Gamma-dot M correlation allows us to estimate the black hole (BH) mass in ESO 243-49 HLX-1 to be M_{BH}~ 7x 10^4 solar masses, assuming the distance to ESO 243-49 of 95 Mpc. For the BH mass estimate we used the scaling method, taking Galactic BHs XTE~J1550-564, H~1743-322 and 4U~1630-472, and an extragalactic BH source, M101 ULX-1 as reference sources. The Gamma-dot M correlation revealed in ESO 243-49 HLX-1 is similar to those in a number of Galactic and extragalactic BHs and it clearly shows the correlation along with the strong Gamma saturation at ~ 3. This is a reliable observational evidence of a BH in ESO 243-49 HLX-1. We also found that the seed (disk) photon temperatures are quite low, of order of 50-140 eV which are consistent with a high BH mass in ESO 243-49 HLX-1.
The long-term Swift monitoring of ESO 243-49 HLX-1 provides an opportunity to investigate the detailed timing and spectral behaviour of this hyper-luminous X-ray source. Swift has detected 7 outbursts since 2009 mid-August. Using different dynamical timing algorithms, we confirm an increasing trend for the time intervals between outbursts, which is manifest in the delays between the latest outbursts. The X-ray spectra of HLX-1 in quiescence can be described with a single power-law model while the thermal component dominates the X-ray emission during outburst. There is only marginal evidence fo…
On the radio properties of the intermediate-mass black hole candidate ESO 243-49 HLX-1
我们使用澳大利亚望远镜紧凑阵列（ATCA）和卡尔G。Jansky甚大阵列（VLA）我们报告了使用ATCA在硬X射线状态期间在HLX-1位置检测到无线电发射的情况。假设“基本面”的吸积黑洞是适用的，我们提供了一个独立的估计黑洞质量的$M_{\rm{BH}}\leq2.8^{+7.5}_{-2.1} \times 10^{6}$ M $_{\odot}$在90%的置信度。然而，我们认为，检测到的无线电发射很可能是多普勒增强，我们的质量估计是一个上限。我们讨论了其他可能的无线电发射的起源，如由于射电星云，恒星形成，或后来的耀斑与大尺度环境的相互作用。这些都被认为是不够的。VLA观测是在X射线爆发期间进行的。然而，没有发现新的射电耀斑，可能是由于稀疏的时间采样。最深的组合VLA数据表明存在可变射电源，我们简要讨论了之前检测到的耀斑的特性，并将其与微类星体和活动星系核进行比较。
Simulations of the tidal interaction and mass transfer of a star in an eccentric orbit around an intermediate-mass black hole: the case of HLX-1
螺旋星系ESO 243-49附近的X射线源HLX-1是目前最好的中等质量黑洞候选者。它的最大热辐射光度为$10^{42}$ erg s $^{-1}$，这意味着它的质量流入率为$\sim10^{-4}$ MSun yr $^{-1}$，但这个质量的来源尚不清楚。有人提出，有一颗恒星在围绕黑洞的偏心轨道上，在近心点转移质量。为了研究这个系统的轨道演化，我们进行恒星演化模拟使用台面和SPH模拟的恒星轨道周围的一个中等质量的黑洞使用FI。我们使用amuse框架运行并耦合这些模拟。我们发现，质量损失通过第一和第二拉格朗日点，有一个延迟的近心点通道和峰值质量损失事件之间的时间长达10天。我们在模拟中发现的轨道演化时间尺度比分析模型预测的要大，但这些模型落在我们结果的误差范围内。尽管轨道演化很快，但我们无法重现观测到的爆发期变化。我们的结论是，在恒星轨道的变化与系统参数的研究在这里是无法解释所有观察到的功能HLX-1。
3XMM J031820.8-663034, first detected by ROSAT in NGC 1313, is one of a few known transient ultraluminous X-ray sources (ULXs). In this paper, we present decades of X-ray data of this source from ROSAT, XMM-Newton, Chandra and the Neil Gehrels Swift Observatory. We find that its X-ray emission experienced four outbursts since 1992, with a typical recurrent time $\sim$ 1800 days, an outburst duration $\sim 240-300$ days, and a nearly constant peak X-ray luminosity $\sim 1.5 \times 10^{39}$ erg/s. The upper limit of X-ray luminosity at the quiescent state is $\sim 5.6 \times 10^{36}$ erg/s, and …
Intermediate-mass black holes (IMBHs) by definition have masses of $M_{\rm IMBH} \sim 10^{2-5}~M_\odot$, a range with few observational constraints. Finding IMBHs in globular star clusters (GCs) would validate a formation channel for massive black-hole seeds in the early universe. Here, we simulate a 60-hour observation with the next-generation Very Large Array (ngVLA) of 728 GC candidates in the Virgo Cluster galaxy NGC\,4472. Interpreting the radio detection thresholds as signatures of accretion onto IMBHs, we benchmark IMBH mass thresholds in three scenarios and find the following: (1) Radi…
It is now widely accepted that most ultraluminous X-ray sources (ULXs) are binary systems whose large (above $10^{39}$ erg s$^{-1}$) apparent luminosities are explained by super-Eddington accretion onto a stellar-mass compact object. Many of the ULXs, especially those containing magnetized neutron stars, are highly variable; some exhibit transient behaviour. Large luminosities might imply large accretion discs that could be therefore prone to the thermal-viscous instability known to drive outbursts of dwarf novae and low-mass X-ray binary transient sources. The aim of this paper is to extend a…
We present the discovery of correlations between the X-ray spectral (photon) index and mass accretion rate observed in active galactic nuclei (AGNs) 3C~454.3 and M87. We analyzed spectral transition episodes observed in these AGNs using Chandra, Swift, Suzaku, BeppoSAX, ASCA and RXTE data. We applied a scaling technique for a black hole (BH) mass evaluation which uses a correlation between the photon index (Gamma) and normalization of the seed component which is proportional to a disk mass accretion rate Mdot. We developed an analytical model that shows that Gamma of the BH emergent spectrum u…
X-ray spectral scaling of black hole mass in quasi-periodic eruptive source RX J1301.9+2747
INAF-IAPS（意大利国家天体物理研究所）；Lomonosov Moscow State University/Sternberg Astronomical Institute（莫斯科罗蒙诺索夫国立大学/斯登伯格天文研究所）；Space Research Institute of the Russian Academy of Sciences（俄罗斯科学院空间研究所）；Lomonosov Moscow State University Branch in the City of Sarov（莫斯科罗蒙诺索夫国立大学萨罗夫分校）；University of Chicago（芝加哥大学）
