Search Publications
Probing the solar transition region: current status and future perspectives
Tian, Hui
The solar transition region (TR) is the temperature regime from roughly 0.02 MK to 0.8 MK in the solar atmosphere. It is the transition layer from the collisional and partially ionized chromosphere to the collisionless and fully ionized corona. The TR plays an important role in the mass and energy transport in both the quiet solar atmosphere and s…
Powerful CMD: a tool for color-magnitude diagram studies
Fan, Zhou; Chen, Li; Li, Zhong-Mu +5 more
We present a new tool for color-magnitude diagram (CMD) studies, Powerful CMD. This tool is built based on the advanced stellar population synthesis (ASPS) model, in which single stars, binary stars, rotating stars and star formation history have been taken into account. Via Powerful CMD, the distance modulus, color excess, metallicity, age, binar…
Surface thermophysical properties on the potentially hazardous asteroid (99942) Apophis
Ip, Wing-Huen; Yu, Liang-Liang; Ji, Jianghui
We investigate the surface thermophysical properties (thermal emissivity, thermal inertia, roughness fraction and geometric albedo) of asteroid (99942) Apophis, using the currently available mid-infrared observations from CanariCam on Gran Telescopio CANARIAS and far-infrared data from PACS on Herschel, based on the Advanced Thermophysical Model. …
Searching for initial stage of massive star formation around the H II region G18.2-0.3
Zhang, Chuan-Peng; Wang, Jun-Jie; Yuan, Jing-Hua +6 more
Sometimes, early star formation can be found in cold and dense molecular clouds, such as an infrared dark cloud. Considering that star formation often occurs in clusters, H II regions may be triggering a new generation of star formation, so we can search for the initial stage of massive star formation around H II regions. Based on the above, this …
How to co-add images? I. A new iterative method for image reconstruction of dithered observations
Wang, Lei; Li, Guo-Liang
By employing the previous Voronoi approach and replacing its nearest neighbor approximation with Drizzle in iterative signal extraction, we develop a fast iterative Drizzle algorithm, named fiDrizzle, to reconstruct the underlying band-limited image from undersampled dithered frames. Compared with the existing iDrizzle, the new algorithm improves …
Updating the orbital ephemeris of the dipping source XB 1254-690 and the distance to the source
Pintore, Fabio; Sanna, Andrea; Gambino, Angelo F. +5 more
XB 1254-690 is a dipping low mass X-ray binary system hosting a neutron star and showing type I X-ray bursts. We aim at obtaining a more accurate orbital ephemeris and at constraining the orbital period derivative of the system for the first time. In addition, we want to better constrain the distance to the source in order to locate the system in …
Joint fit of Warm Absorbers in COS and HETG spectra of NGC 3783
Sun, Wei; Ji, Li; Fu, Xiao-Dan +2 more
Warm Absorbers (WAs), as an important form of AGN outflows, show absorption in both the UV and X-ray bands. Using XSTAR generated photoionization models, for the first time we present a joint fit to the simultaneous observations of HST/COS and Chandra/HETG on NGC 3783. A total of five WAs explain well all absorption features from the AGN outflows,…
Quasars in the Galactic Anti-Center Area from LAMOST DR3
Zhang, Yong; Yuan, Hai-Bo; Huang, Yang +11 more
We present a sample of quasars discovered in an area near the Galactic Anti-Center covering 150^\circ ≤ l≤ 210^\circ and | b| ≤ 30^\circ , based on LAMOST Data Release 3 (DR3). This sample contains 151 spectroscopically confirmed quasars. Among them 80 are newly discovered with LAMOST. All these quasars are very bright, with i magnitudes peaking a…
An application of the KNND method for detecting nearby open clusters based on Gaia-DR1
Gao, Xin-Hua
This paper presents a preliminary test of the k-th nearest neighbor distance (KNND) method for detecting nearby open clusters based on Gaia-DR1. We select 38 386 nearby stars (< 100 {pc}) from the Gaia-DR1 catalog, and then use the KNND method to detect overdense regions in three-dimensional space. We find two overdense regions (the Hyades and …
Peak flux of flares associated with coronal mass ejections
Suryanarayana, Gadikere Sheshagiriyappa; Balakrishna, Kagalagodu Manjunathayya
Features of flares that occur in association with coronal mass ejections (CMEs) have often displayed variations compared to flares with no associated CMEs. A comparative estimation of peak flux values of flares associated with CMEs and those without CMEs is made. Peak flux values of flares associated with CMEs show distinctly higher values in comp…