Search Publications
Broad-band spectroscopy of the transient X-ray binary pulsar KS 1947+300 during 2013 giant outburst: Detection of pulsating soft X-ray excess component
Naik, Sachindra; Jaisawal, Gaurava K.; Epili, Prahlad
We present the results obtained from detailed timing and spectral studies of the Be/X-ray binary pulsar KS 1947+300 during its 2013 giant outburst. We used data from Suzaku observations of the pulsar at two epochs, i.e. on 2013 October 22 (close to the peak of the outburst) and 2013 November 22. X-ray pulsations at ∼18.81 s were clearly detected i…
Smoothing methods comparison for CMB E- and B-mode separation
Wang, Yi-Fan; Wang, Kai; Zhao, Wen
The anisotropies of the B-mode polarization in the cosmic microwave background radiation play a crucial role in the study of the very early Universe. However, in real observations, a mixture of the E-mode and B-mode can be caused by partial sky surveys, which must be separated before being applied to a cosmological explanation. The separation meth…
NUV Star Catalog from the Lunar-based Ultraviolet Telescope Survey: First Release
Wang, Jing; Meng, Xian-Min; Wei, Jian-Yan +7 more
We present a star catalog extracted from the Lunar-based Ultraviolet Telescope (LUT) survey program. LUT's observable sky area is a circular belt around the Moon's north pole, and the survey program covers a preferred area of about 2400 deg2 which includes a region of the Galactic plane. The data are processed with an automatic pipeline…
Probing the Lambda-DGP Braneworld model
Ravanpak, Arvin; Farajollahi, Hossein; Fadakar, Golnaz
We study cosmic dynamics in the context of the normal branch of the DGP braneworld model. Using current Planck data, we find the best fitting model and associated cosmological parameters in non-flat ΛDGP. With the transition redshift as a basic variable and statefinder parameters, our result shows that the Universe starts its accelerated expansion…
A fast Stokes inversion technique based on quadratic regression
Teng, Fei; Deng, Yuan-Yong
Stokes inversion calculation is a key process in resolving polarization information on radiation from the Sun and obtaining the associated vector magnetic fields. Even in the cases of simple local thermodynamic equilibrium (LTE) and where the Milne-Eddington approximation is valid, the inversion problem may not be easy to solve. The initial values…
The orbital phase resolved spectroscopy of X-ray binary 4U 1822-371 with Suzaku
Ji, Li; Nowak, Michael A.; Schulz, Norbert S. +3 more
4U 1822-371 is a typical edge-on eclipsing low mass X-ray binary and the prototype of accretion disk coronal sources. We report on the results of a spectral analysis over the energy range 0.5-45 keV observed by Suzaku in 2006. We extract spectra from five orbital phases. The spectra can be equally well described by various previously proposed mode…
On the reality of broad iron L lines from the narrow line Seyfert 1 galaxies 1H 0707-495 and IRAS 13224-3809.
Misra, R.; Dewangan, G. C.; Pawar, P. K. +2 more
We performed time resolved spectroscopy of 1H0707-495 and IRAS 13224-3809 using long XMM-Newton observations. These are strongly variable narrow line Seyfert 1 galaxies and show broad features around 1 keV that has been interpreted as relativistically broad Fe L$\alpha$ lines. Such features are not clearly observed in other AGN despite sometimes h…
Kinematic properties of the dual AGN system J0038+4128 based on long-slit spectroscopy
Huang, Yang; Liu, Xiao-Wei; Bai, Jin-Ming +2 more
The study of kiloparsec-scale dual active galactic nuclei (AGN) provides important clues for understanding the co-evolution between host galaxies and their central supermassive black holes undergoing a merging process. We present long-slit spectroscopy of J0038+4128, a kiloparsec-scale dual AGN candidate, discovered recently by Huang et al., using…
UV and X-ray variability of the narrow-line Seyfert 1 galaxy Ark 564
Dewangan, Gulab C.; Kembhavi, Ajit K.; Misra, Ranjeev +3 more
We analyze eight XMM-Newton observations of the bright Narrow Line Seyfert 1 galaxy Arakelian 564 (Ark 564). These observations, separated by ∼ 6 days, allow us to look for correlations between the simultaneous ultraviolet (UV) emission (from the Optical Monitor) with not only the X-ray flux but also with different X-ray spectral parameters. The X…
Sharp Chandra View of ROSAT All-Sky Survey Bright Sources — I. Improvement of Positional Accuracy
Wang, Song; Liu, Ji-Feng; Gao, Shuang
The ROSAT All-Sky Survey (RASS) represents one of the most complete and sensitive soft X-ray all-sky surveys to date. However, the deficient positional accuracy of the RASS Bright Source Catalog (BSC) and subsequent lack of firm optical identifications affect multi-wavelength studies of X-ray sources. The widely used positional errors σpos