Search Publications
Pulsations and period variations of the δ Scuti star AN Lyncis in a possible three-body system
Li, Gang; Su, Jie; Fu, Jianning +5 more
Observations for the δ Scuti star AN Lyn have been made between 2008 and 2016 with the 85-cm telescope at Xinglong station of National Astronomical Observatories of China, the 84-cm telescope at SPM Observatory of Mexico and the Nanshan One metre Wide field Telescope of Xinjiang Observatory of China. Data in V in 50 nights and in R in 34 nights ar…
An ultraviolet study of B[e] stars: evidence for pulsations, luminous blue variable type variations and processes in envelopes
Krtička, J.; Krtičková, I.
Stars that exhibit a B[e] phenomenon comprise a very diverse group of objects in a different evolutionary status. These objects show common spectral characteristics, including the presence of Balmer lines in emission, forbidden lines and strong infrared excess due to dust. Observations of emission lines indicate illumination by an ultraviolet ioni…
A Suzaku X-ray study of the mixed-morphology supernova remnant Kes 69 and searching for its gamma-ray counterpart
Sezer, A.; Yamazaki, R.; Ergin, T. +2 more
Kes 69 is a mixed-morphology (MM) supernova remnant (SNR) that is known to be interacting with molecular clouds based on 1720 MHz hydroxyl (OH) maser emission observations in the northeastern and southeastern regions. We present an investigation of Kes 69 using ∼67 ks Suzaku observation. The X-ray spectrum of the whole SNR is well fitted by a non-…
SMHASH: a new mid-infrared RR Lyrae distance determination for the Local Group dwarf spheroidal galaxy Sculptor
Majewski, Steven R.; Madore, Barry F.; Freedman, Wendy L. +12 more
We present a new distance estimation for the Milky Way dwarf spheroidal satellite Sculptor obtained from multi-epoch mid-infrared observations of RR Lyrae stars (RRLs). The 3.6 µm observations have been acquired with the Infrared Array Camera onboard the Spitzer Space Telescope as part of the SMHASH program. Mid-infrared light curves for 42 …
Probing the dynamical state, baryon content, and multiphase nature of galaxy clusters with bright background QSOs
Tripp, Todd M.; Burchett, Joseph N.; Wang, Q. Daniel +5 more
We have initiated a programme to study the physical/dynamical state of gas in galaxy clusters and the impact of the cluster environment on gaseous haloes of individual galaxies using X-ray imaging and UV absorption line spectroscopy of background QSOs. Here, we report results from the analysis Chandra and XMM-Newton archival data of five galaxy cl…
Changes in the pulse phase dependence of X-ray emission lines in 4U 1626-67 with a torque reversal
Paul, Biswajit; Beri, Aru; Dewangan, Gulab C.
We report results from an observation with the XMM-Newton observatory of a unique X-ray pulsar 4U 1626-67. European Photon Imaging Camera-pn data during the current spin-up phase of 4U 1626-67 have been used to study pulse phase dependence of low-energy emission lines. We found strong variability of low-energy emission line at 0.915 keV with the p…
3D mapping of the neutral X-ray absorption in the local interstellar medium: the Gaia and XMM-Newton synergy
Wilms, J.; García, Javier A.; Kallman, Timothy R. +4 more
We present a three-dimensional map of the hydrogen density distribution in the Galactic interstellar medium. The hydrogen-equivalent column densities were obtained from the Exploring the X-ray Transient and variable Sky project (EXTRAS) which provides equivalent NH values from X-ray spectral fits of observations within the XMM-Newton Da…
Intermittency spectra of current helicity in solar active regions
Zhang, Hongqi; Abramenko, V. I.; Kuzanyan, K. M. +2 more
We analyse the spatial distribution of current helicity in solar active regions. A comparison of current helicity maps derived from three different instruments (Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, SDO/HMI, Spectro-Polarimeter on board the Hinode, and Solar Magnetic Field Telescope at the Huairou Solar Observin…
Polarimetric and spectroscopic study of radio-quiet weak emission line quasars
Stalin, C. S.; Petitjean, P.; Srianand, R. +3 more
A small subset of optically selected radio-quiet quasars showing weak or no emission lines may turn out to be the elusive radio-quiet BL Lac objects, or simply be radio-quiet QSOs with a still-forming/shielded broad line region (BLR). High polarization (p > 3-4 per cent), a hallmark of BL Lacs, can be used to test whether some optically selecte…
Thermophysical modelling for high-resolution digital terrain models
Pelivan, I.
A method is presented for efficiently calculating surface temperatures for highly resolved celestial body shapes. A thorough investigation of the necessary conditions leading to reach model convergence shows that the speed of surface temperature convergence depends on factors such as the quality of initial boundary conditions, thermal inertia, ill…