Jingzhi Yan

DISCRETE MASS EJECTIONS FROM THE Be/X-RAY BINARY A0535+26/HD 245770

We present long-term optical spectroscopic observations on the Be/X-ray binary A0535+26 from 1992 to 2010. Combined with the public V-band photometric data, we find that each giant X-ray outburst occurred in a fading phase of the optical brightness. The anti-correlation between the optical brightness and the H alpha intensity during our 2009 observations indicates a mass ejection event had taken place before the 2009 giant X-ray outburst, which might cause the formation of a low-density region in the inner part of the disk. The similar anti-correlation observed around 1996 September indicates the occurrence of the mass ejection, which might trigger the subsequent disk loss event in A0535+26.

Multi-wavelength Study of the Be/X-Ray Binary MXB 0656–072

We present and analyze the optical photometric and spectroscopic data of the Be/X-ray binary MXB 0656-072 from 2006 to 2009. A 101.2 day orbital period is found, for the first time, from the present public X-ray data (Swift/BAT and RXTE/ASM). The anti-correlation between the Ha emission and the UBV brightness of MXB 0656-072 during our 2007 observations indicates that a mass ejection event took place in the system. After the mass ejection, a low-density region might develop around the Oe star. With the outward motion of the circumstellar disk, the outer part of the disk interacted with the neutron star around its periastron passage and a series of X-ray outbursts were triggered between MJD 54350 and MJD 54850. The Proportional Counter Array-HEXTE spectra during the 2007-2008 X-ray outbursts could be well fitted by a cutoff power law with low-energy absorption, together with an iron line around 6.4 keV, and a broad cyclotron resonance feature around 30 keV. The same variability of the soft and hard X-ray colors in 2.3-21 keV indicated that there were no overall changes in the spectral shape during the X-ray outbursts, which might only be connected with the changes of the mass accretion rate onto the neutron star.

Optical spectroscopic observations of Cyg X-1=HDE 226868

We present the results of the spectroscopic observations of HDE 226868, the optical counterpart to the black hole X-ray binary Cyg X-1, from 2001 to 2006. We analyze the variabilities of the two components in the complex Hα line: one P-Cygni shaped component which follows the motion of the supergiant and another emission component moving with an antiphase orbital motion relative to the supergiant, which is attributed to a focused stellar wind. The results of KOREL disentangling of our spectra indicate that the focused stellar wind is responsible for the major part of the variability of the Hα emission line. The emission of the supergiant component had a small difference between the low/hard and high/soft states, while the focused-wind component became strong in the low/hard state and weak in the high/soft state. The wind is nearly undisturbed by the X-ray photoionization during the low/hard state. However, during the high/soft state, the X-rays from the compact object could decelerate the line-driven wind and result in a high-mass accretion rate, due to the effect of the X-ray photoionization. The X-ray illuminating could also change the temperature profile of the stellar wind and increase its temperature, and thus decrease the Hα emissivity of the wind, which could explain the Hα variabilities of Cyg X-1 during different X-ray states.

Optical Spectroscopic Observations of CI Camelopardalis

We present the results of optical spectroscopic observations of CI Cam. Double- peaked profiles were simultaneously observed for the first time in the hydrogen Balmer, He I lambda 6678, and Fe II lines during an observational run in 2001 September. An intermediate viewing angle of the circumstellar disk around the B[e] star is consistent with our data. A significant decrease in the intensity of the H alpha and He I lines in our 2004 September observations might have been the precursor of a line outburst at the end of 2004. The remarkable increase in the intensity of all lines and the decrease in visual brightness in 2005 might be due to the environment filling with new material ejected during the outburst. The environment of CI Cam is influenced by mass loss from the B[e] star and the outburst of its compact companion.

Two transient X-ray Quasi-Periodic Oscillations separated by an intermediate state in 1H 0707-495

In the narrow-line Seyfert 1 galaxy 1H 0707-495, recently a transient quasi-periodic oscillation (QPO) signal has been detected at a high statistical significance. Here, we reanalyze the same set of XMM-Newton data measured on 2008 February 4 with the Weighted-Wavelet Z-transform (WWZ) method. In addition to confirm the previous finding we find the other QPO signal in a separated X-ray emission phase at a confidence level of

An X-Ray Periodicity of ∼1.8 hr in Narrow-line Seyfert 1 Galaxy Mrk 766

\sim 4.1\sigma

LONG-TERM OPTICAL OBSERVATIONS OF THE Be/X-RAY BINARY X PER

. The frequency ratio between these two signals is

Gamma-ray emission from globular clusters 2MS-GC01, IC 1257, FSR 1735, NGC 5904 and 6656

\sim 2:1

Detection of gamma-ray emission from globular clusters M15, NGC 6397, 5904, 6218 and 6139 with Fermi-LAT

. These two signals also appeared, though at lower significance levels, in XMM-Newton measurements on 2007 May 14 and 2010 September 17, individually. This is the first time to observe two separated transient X-ray QPOs in active galactic nuclei (AGNs), which sheds new light on the physics of accreting supermassive black holes.

LONG-TERM OPTICAL STUDIES OF THE BE/X-RAY BINARY RX J0440.9+4431/LS V+44 17

In the narrow-line Seyfert 1 galaxy Mrk 766, a Quasi-Periodic Oscillation (QPO) signal with a period of