Search Publications
Evolution of isolated G-band bright points: size, intensity and velocity
Feng, Song; Wang, Feng; Deng, Hui +3 more
We study the evolution pattern of isolated G-band bright points (GBPs) in terms of their size, intensity and velocity. Using a high resolution image sequence taken with the Hinode/Solar Optical Telescope (SOT), we detect GBPs in each image by the Laplacian and Morphological Dilation algorithm, and track their evolutions by a 26-adjacent method in …
Observations of counter-propagating Alfvénic and compressive fluctuations in the chromosphere
He, Jian-Sen; Liu, Zi-Xu; Yan, Li-Mei
Recent observations have found that chromospheric spicules behave like Alfvénic fluctuations. Low-frequency Alfvén waves are predicted to partially reflect in the transition region that has a gradient in the Alfvén speed, thereby producing inward Alfvén waves, which may interact nonlinearly with outward Alfvén waves to generate Alfvénic turbulence…
Hard X-ray emission cutoff in the anomalous X-ray pulsar 4U 0142+61 detected by INTEGRAL
Wang, Wei; Guo, Yan-Jun; Tong, Hao
The anomalous X-ray pulsar 4U 0142+61 has been studied with observations from INTEGRAL. The hard X-ray spectrum in the range 18-500 keV for 4U 0142+61 was derived using nearly nine years of INTEGRAL/IBIS data. We obtained the average hard X-ray spectrum of 4U 0142+61 with all available data. The spectrum of 4U 0142+61 can be fitted with a power la…
Photometric investigation of the K-type extremely shallow contact binary V1799 Orion
Qian, Sheng-Bang; Liao, Wen-Ping; He, Jia-Jia +3 more
New multi-color light curves of the very short period K-type eclipsing binary V1799 Ori were obtained and analyzed with the Wilson-Devinney code. The photometric solutions reveal that the system is a W-type shallow-contact binary with a mass ratio of q = 1.335(±0.005) and a degree of contact of about f = 3.5(±1.1)%. In general, the results are in …
Temporal variations and spectral properties of the Be/X-ray pulsar GRO J1008—57 studied by INTEGRAL
Wang, Wei
The spin period variations and hard X-ray spectral properties of the Be/X-ray pulsar GRO J1008—57 are studied with INTEGRAL observations during two outbursts in 2004 June and 2009 March. The pulsation periods of ~ 93.66 s in 2004 and ~ 93.73 s in 2009 are determined. Pulse profiles of GRO J1008—57 during outbursts are strongly energy dependent wit…
Association of CMEs with solar surface activity during the rise and maximum phases of solar cycles 23 and 24
Li, Ting; Zhang, Jun; Gao, Peng-Xin
The cyclical behaviors of sunspots, flares and coronal mass ejections (CMEs) for 54 months from 2008 November to 2013 April after the onset of Solar Cycle (SC) 24 are compared, for the first time, with those of SC 23 from 1996 November to 2001 April. The results are summarized below. (i) During the maximum phase, the number of sunspots in SC 24 is…
On the line profile changes observed during the X2.2 class flare in the active region NOAA 11158
Raja Bayanna, Ankala; Kumar, Brajesh; Venkatakrishnan, Parameswaran +4 more
The solar active region NOAA 11158 produced a series of flares during its passage through the solar disk. The first major flare (of class X2.2) of the current solar cycle occurred in this active region on 2011 February 15 around 01:50 UT. We have analyzed the Dopplergrams and magnetograms obtained by the Helioseismic and Magnetic Imager (HMI) inst…
Identification of emission sources of umbral flashes using phase congruency
Feng, Song; Ji, Kai-Fan; Yang, Yun-Fei +1 more
The emission sources of umbral flashes (UFs) are believed to be closely related to running umbral and penumbral waves, and are concluded to be associated with umbral dots in the solar photosphere. Accurate identification of emission sources of UFs is crucial for investigating these physical phenomena and their inherent relationships. A relatively …
Spacecraft Doppler tracking with possible violations of LLI and LPI: preliminary bounds on LLI from Mars Express
Xie, Yi; Huang, Yong; Zhang, Yu-Fei +2 more
Three-way spacecraft Doppler tracking is currently widely used and it plays an important role in the control and navigation of deep space missions. Using the theory of three-way Doppler tracking, including possible violations of the local Lorentz invariance (LLI) and the local position invariance (LPI), we analyze the post-fit residuals of three-w…
The star formation history of redshift z ~ 2 galaxies: the role of the infrared prior
Nonino, Mario; Lapi, Andrea; De Zotti, Gianfranco +3 more
We build a sample of 298 spectroscopically-confirmed galaxies at redshift z ~ 2, selected in the z850-band from the GOODS-MUSIC catalog. By utilizing the rest frame 8 µm luminosity as a proxy of the star formation rate (SFR), we check the accuracy of the standard SED-fitting technique, finding it is not accurate enough to provide …