Recent gamma-ray and anti-proton analyses suggest that dark matter with mass $m=48-67$ GeV annihilating via $b\bar{b}$ channel can explain the Galactic center GeV gamma-ray excess and the anti-proton excess as measured by AMS-02 simultaneously. In this article, by differentiating the contributions of dark matter annihilation and normal diffuse cosmic rays, we show that dark matter with mass $m=40-50$ GeV annihilating via $b\bar{b}$ channel with the thermal relic annihilation cross section can best explain the radio continuum spectrum of the central radio halo of the Ophiuchus cluster. This mass range, annihilation cross section, and the annihilation channel is completely consistent with the dark matter interpretations of the GeV gamma-ray excess and the anti-proton excess.
MAXI J1305-704 is a transient X-ray binary with a black hole primary. It was discovered on April 9, 2012, during its only known outburst. MAXI J1305-704 is also a high inclination low-mass X-ray binary with prominent dip features in its light curves, so we check the full catalog of 92 \emph{Swift}/XRT continuous observations of MAXI J1305-704, focusing only on the stable spectra. We select 13 ``gold" spectra for which the root mean square RMS <0.075 and the coronal scattered fraction $f_{\mathrm{sc}} \lesssim 25 \%$. These ``gold" data are optimal thermal-state observations for continuum-fitti…
The iron line and the continuum-fitting methods are currently the two leading techniques for measuring black hole spins with electromagnetic radiation. They can be naturally extended for probing the spacetime geometry around black holes and testing general relativity in the strong field regime. In the past couple of years, there has been significant work to use the iron line method to test the nature of black holes. In this Letter, we use the continuum-fitting method and we show its capability of constraining the spacetime geometry around black holes by analyzing 17 RXTE data of the X-ray bina…
The continuum-fitting and the iron line methods are currently the two leading techniques for probing the strong gravity region around accreting black holes. In the present work, we test the Kerr black hole hypothesis with the stellar-mass black hole in GRS 1915+105 by analyzing five disk-dominated RXTE spectra and one reflection-dominated Suzaku spectrum. The combination of the constraints from the continuum-fitting and the iron line methods has the potential to provide more stringent tests of the Kerr metric. Our constraint on the Johannsen deformation parameter $α_{13}$ is $-0.15 < α_{13} < …
As a transient X-ray binary, MAXI J1659-152 contains a black hole candidate as its compact star. MAXI J1659-152 was discovered on 2010 September 25 during its only known outburst. Previously-published studies of this outburst indicate that MAXI J1659-152 may have an extreme retrograde spin, which, if confirmed, would provide an important clue as to the origin of black hole spin. In this paper, utilizing updated dynamical binary-system parameters (i.e. the black hole mass, the orbital inclination and the source distance) provided by \cite{Torres2021}, we analyze 65 spectra of MAXI J1659-152 fro…
The continuum-fitting method is the analysis of the thermal spectrum of the geometrically thin and optically thick accretion disk around stellar-mass black holes. A parametrization aiming to test the Kerr nature of astrophysical black holes was proposed in Ghasemi-Nodehi and Bambi in EPJC 76: 290, 2016. The metric contains 11 parameters in addition to the mass and spin parameters. One can recover the Kerr case by setting all parameters to one. In this paper, I study the continuum-fitting method in Ghasemi-Nodehi-Bambi background. I show the impact of each of the parameters on the spectra. I th…
The continuum-fitting and the iron-line methods are currently the two leading techniques for measuring the spins of accreting black holes. In the past few years, these two methods have been developed for testing fundamental physics. In the present work, we employ state-of-the-art models to test black holes through the continuum-fitting and the iron-line methods and we analyze three NuSTAR observations of the black hole binary GRS 1716-249 during its outburst in 2016-2017. In these three observations, the source was in a hard-intermediate state and the spectra show both a strong thermal compone…
Spin Constraints on 4U 1630-47 via combined Continuum Fitting and Reflection methods: a comparative study using Frequentist and Bayesian statistics
Fudan University（复旦大学）；Eberhard-Karls Universität Tübingen（蒂宾根大学）；University of Oxford（牛津大学）；New Uzbekistan University（新乌兹别克斯坦大学）；University of Warwick（华威大学）；Max Planck Institute for Extraterrestrial Physics（马克斯·普朗克地外物理学研究所）
Testing the Kerr-nature of stellar-mass black hole candidates by combining the continuum-fitting method and the power estimate of transient ballistic jets
The two established techniques for measuring black hole spin in X-ray binaries often yield conflicting results, which must be resolved before either method may be deemed robust. In practice, black hole spin measurements based on fitting the accretion disc continuum effectively do not marginalize over the colour correction factor $f_{\mathrm{col}}$. This factor parametrizes spectral hardening of the disc continuum by the disc atmosphere, whose true properties are poorly constrained. We incorporate reasonable systematic uncertainties in $f_{\mathrm{col}}$ into the eight (non-maximal) black hole …
The spins of ten stellar black holes have been measured using the continuum-fitting method. These black holes are located in two distinct classes of X-ray binary systems, one that is persistently X-ray bright and another that is transient. Both the persistent and transient black holes remain for long periods in a state where their spectra are dominated by a thermal accretion disk component. The spin of a black hole of known mass and distance can be measured by fitting this thermal continuum spectrum to the thin-disk model of Novikov and Thorne; the key fit parameter is the radius of the inner …
We develop a new model for X-ray emission from tidal disruption events (TDEs), applying stationary general relativistic ``slim disk'' accretion solutions to supermassive black holes (SMBHs) and then ray-tracing the photon trajectories from the image plane to the disk surface, including gravitational redshift, Doppler, and lensing effects self-consistently. We simultaneously and successfully fit the multi-epoch XMM-Newton X-ray spectra for two TDEs: ASASSN-14li and ASASSN-15oi. We test explanations for the observed, unexpectedly slow X-ray brightening of ASASSN-15oi, including delayed disk form…
Confirmation Via the Continuum-Fitting Method that the Spin of the Black Hole in Cygnus X-1 is Extreme
在Gou et al.（2011）中，我们报道了X射线双星天鹅座X-1中的主要黑洞是一个自旋参数a*>0.95（3σ）的近极端克尔黑洞。我们确认了这一结果，同时设定了一个新的更严格的限度：在3σ（99.7%）置信水平下，a*>0.983。早期的工作是基于对所有三个可用光谱的分析，可能是由于这些光谱中存在相对较强的康普顿幂律成分而产生的偏差：散射到幂律中的热种子光子的比例为f_s=23- 31%，而连续拟合方法可靠应用的上限是f_s<25%。随后，我们又获得了天鹅座X-1的六个适合于测量自旋的光谱。其中五个光谱具有高质量，f_s在10%至19%的范围内，连续拟合方法已被证明可以提供可靠的结果。单独地，六个光谱给出了自旋参数的下限，范围从a*>0.95到a*>0.98，使我们能够保守地得出结论，黑洞的自旋是a*>0.983（3σ）。
Probing the space-time geometry around black hole candidates with the resonance models for high-frequency QPOs and comparison with the continuum-fitting method
The splash beneath the largest radio bubble in a cluster core
School of Physics & Astronomy, University of Nottingham（诺丁汉大学物理与天文学学院）；ICRAR, University of Western Australia（西澳大利亚大学ICRAR）；Waterloo Centre for Astrophysics, University of Waterloo（滑铁卢大学天体物理中心）；Max-Planck-Institut für extraterrestrische Physik（马普地外物理研究所）；Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University（马萨里克大学理学院理论物理与天体物理学系）
Weak emission line quasar SDSS J101353.45+492758.1 I. Continuum fitting
University of Białystok（比亚韦斯托克大学）；Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences（波兰科学院尼古拉·哥白尼天文学中心）；National Centre for Nuclear Research（国家核研究中心）
