GRS 1915+105 is a very well studied microquasar with a wide variety of temporal and spectral states. Multi-wavelength observations from radio to X-rays have uncovered clear relations between the variability in different bands. GRS 1915+105 is also well-known as a source of superluminal jets moving away from the core with true velocity <=0.9c. Non-thermal emission from the jets or their termination shock could extend to the VHE gamma-ray domain. GRS 1915+105 was observed with the H.E.S.S. telescope array between 2004 and 2008 for a total of 24 hours. We report on these observations and discuss our findings.
The microquasar GRS 1915+105 is known to exhibit a very variable X-ray emission on different time scales and patterns. We propose a system of two ordinary differential equations, adapted from the Hindmarsh-Rose model, with two dynamical variables x(t), y(t) and an input constant parameter J_0, to which we added a random white noise, whose solutions for the x(t) variable reproduce consistently the X-ray light curves of several variability classes as well as the development of low frequency Quasi-Periodic Oscillations (QPO). We show that changing only the value of J_0 the system moves from stabl…
Discovery of Unusual Jet Orientation Variations in the Microquasar GRS 1915+105
Xinjiang Astronomical Observatory, CAS（中国科学院新疆天文台）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences（孔科利天文台，匈牙利研究与教育网络天文学与地球科学研究中心）；Special Astrophysical Observatory of the Russian Academy of Sciences（俄罗斯科学院特别天体物理观测站）
射电星系和微类星体之间的家族联系由于一个新的共同现象而得到了强烈的加强：扩展的翅膀特征的存在。最近在《自然通讯》（http：//rdcu.be/zgX8）上报道的银河系微类星体中首次探测到这种结构，拓宽了两种外流源之间已知的相似性（Martí et al. 2017）。这一观测结果也有潜在的影响，影响黑洞合并的情况下，有助于引力波的背景。
The X-ray emission from the microquasar GRS 1515+105 shows, together with a very complex variability on different time scales, the presence of low-frequency quasi periodic oscillations (LFQPO) at frequencies lower than 30 Hz. In this paper, we demonstrate that these oscillations can be consistently and naturally obtained as solutions of a system of two ordinary differential equations that is able to reproduce almost all variability classes of GRS 1515+105. We modified the Hindmarsh-Rose model and obtained a system with two dynamical variables x(t), y(t), where the first one represents the X-ra…
The complex time evolution in the X-ray light curves of the peculiar black hole binary GRS 1915+105 can be obtained as solutions of a non-linear system of ordinary differential equations derived form the Hindmarsch-Rose model and modified introducing an input function depending on time. In the first paper,assuming a constant input with a superposed white noise, we reproduced light curves of the classes rho, chi, and delta. We use this mathematical model to reproduce light curves, including some interesting details, of other eight GRS 1915+105 variability classes either considering a variable i…
We present Atacama Large Millimeter/Sub-millimeter Array observations of the candidate jet-ISM interaction zones near the black hole X-ray binaries GRS 1758$-$258 and 1E 1740.7$-$2942. Using these data, we map the molecular line emission in the regions, detecting emission from the HCN [$J=1-0$], HCO$^+$ [$J=1-0$], SiO [$J=2-1$], CS [$J=2-1$], $^{13}$CO [$J=1-0$], C$^{18}$O [$J=1-0$], HNCO [$J=4_{0,4}-3_{0,3}$], HNCO [$J=5_{0,5}-4_{0,4}$], and CH$_3$OH [$J=2_{1,1}-1_{1,0}$] molecular transitions. Through examining the morphological, spectral, and kinematic properties of this emission, we identi…
A search for very high-energy flares from the microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr using contemporaneous H.E.S.S. and RXTE observations
微类星体是潜在的$γ$射线发射体。最近在至少两个系统中报告了$γ$射线发射的短暂发作迹象：Cyg X-1和Cyg X-3。为了更好地理解$γ$射线是如何在这些系统中产生的，需要识别额外的$γ$射线发射微类星体。理论模型已经预测了微类星体在短暂爆发期间会发射甚高能量（VHE）$γ$射线。本文报告的观测目的是观测$γ$射线和X射线波段的宽带耀斑事件。利用高能光谱系统（H.E.S.S.）对三颗微类星体GRS 1915+105、Circinus X-1和V4641 Sgr进行了同期观测。这是由Rossi X射线定时探测器（RXTE）卫星和望远镜阵列组成的。对每个微类星体进行了X射线分析，并从同时期的H.E.S.S. S获得了VHE $γ$射线上限。观察得出。在三个系统中均未检测到显著的$γ$射线信号。对于GRS 1915+105、Circinus X-1和V4641 Sgr，观测历元的积分$γ$射线光子通量分别被限制为$I(> 560 {\rm\ GeV}) < 7.3\times10^{-13}$ cm $^{-2}$ s $^{-1}$、$I(> 560 {\rm\ GeV}) < 1.2\times10^{-12}$ cm $^{-2}$ s $^{-1}$和$I(> 240 {\rm\ GeV}) < 4.5\times10^{-12}$ cm $^{-2}$ s $^{-1}$。…
The temporal behaviour of X-rays from some AGN and microquasars is thought to arise from the rapid collapse of the hot, inner parts of their accretion discs. The collapse can occur over the radial infall timescale of the inner accretion disc. However, estimates of this timescale are hindered by a lack of knowledge of the operative viscosity in the collisionless plasma comprising the inner disc. We use published simulation results for cosmic ray diffusion through turbulent magnetic fields to arrive at a viscosity prescription appropriate to hot accretion discs. We construct simplified disc mode…
A Multi-messenger Search for a Nearby Microquasar Contributor to the Cosmic Ray Knee
School of Physical Science and Technology, Southwest Jiaotong University（西南交通大学物理科学与技术学院）；State Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所粒子天体物理国家重点实验室）；University of Chinese Academy of Sciences（中国科学院大学）；TIANFU Cosmic Ray Research Center（天府宇宙线研究中心）
Microquasars with high-mass companion stars are promising very-high-energy (VHE; 0.1-100 TeV) gamma-ray emitters, but their behaviors above 10 TeV are poorly known. Using the High Altitude Water Cherenkov (HAWC) observatory, we search for excess gamma-ray emission coincident with the positions of known high-mass microquasars (HMMQs). No significant emission is observed for LS 5039, Cygnus X-1, Cygnus X-3, and SS 433 with 1,523 days of HAWC data. We set the most stringent limit above 10 TeV obtained to date on each individual source. Under the assumption that HMMQs produce gamma rays via a comm…
Aims. The prototypical microquasar GRS 1758-258 exhibits large-scale morphological changes in radio maps over time which have been attributed to the rise of instabilities. Here, we investigate whether these effects could be attributed to jet precession instead. Methods.We used new and archival radio maps to fit a kinematic jet precession model. The value of the parameters thus obtained were analysed in order to get constraints on the physical properties of the GRS 1758-258 system. Their consistency with different theories of the origins for the jet precession, such as Lense-Thirring effect and…
