LATEST NEWS

Thick-disc model to explain the spectral state transition in NGC 247

Abstract: We propose the thick-disc model of Gu et al. 2016 to interpret the transition between soft ultraluminous state (SUL) and supersoft ultraluminous state (SSUL) in NGC247. As accretion rate increases, the inner disc will puff up and act as shield to block the innermost X-ray emission regions and absorb both soft and hard X-ray photons. The absorbed X-ray emission will be re-radiated as a...

A method to search for black hole candidates with giant companions by LAMOST

Recently, by using the LAMOST spectra, Prof. Wei-Min Gu and his collaborators have published a paper in ApJ Letters (ApJL, 872, L20) on a new method to search for stellar-mass black hole candidates. Based on the stellar spectra of LAMOST Data Release 6, a sample of seven giants in binaries is obtained with large radial velocity variation (> 80 km/s). With the effective temperature, surface grav...

Quark mean-field model for nuclear matter with or without bag

Authors: Zhen-Yu Zhu, Ang Li*, Jin-Niu Hu, Hong Shen​ | Abstract: We propose the new quark mean-field bag (QMFB) model by incorporating the bag confinement mechanism in the original quark mean-field model. ..

Spectral Energy Distribution of the inner accretion flow around Sgr A* -- Clue for a weak outflow in the innermost region

Sgr A* represents a unique laboratory for the detailed study of accretion processes around a low-luminosity supermassive black hole (SMBH). Recent X-ray observations have allowed for spatially resolved modeling of the emission from the accretion flow around the SMBH, placing tight constraints on the flux and spectral shape of the accretion from the inner region with $r<10^3~r_g$, where $r_g$ is...

Neutron star equation of state from the quark level in the light of GW170817

Matter state inside neutron stars is an exciting problem in astrophysics, nuclear physics and particle physics. The equation of state (EOS) of neutron stars plays a crucial role in the present multimessenger astronomy, especially after the event of GW170817. We propose a new neutron star EOS ``QMF18'' from the quark level, which describes well robust observational constraints from free-space ...

A lower occurrence rate of bright X-ray flares in SN-GRBs than z<1 GRBs: evidence of energy partitions?

Authors: Hui-Jun Mu, Wei-Min Gu, Jirong Mao, Tong Liu, Shu-Jin Hou, Da-Bin Lin, Junfeng Wang, Taotao Fang, En-Wei Liang Abstract: The occurrence rates of bright X-ray flares in z < 1 gamma-ray bursts (GRBs) with or without observed supernovae (SNe) association were compared. Our Sample I: the z < 1 long GRBs (LGRBs) with SNe association (SN-GRBs) and with early Swift/X- Ray Telescope (XRT) observations, consists of 18 GRBs, among which only two GRBs have bright X-ray flares. Our Sample II: for comparison, all the z < 1 LGRBs without observed SNe association and with early Swift/XRT observations, consists of 45 GRBs, among which 16 GRBs present bright X-ray flares...

more news...