Search Publications
A Chandra X-Ray Study of the Interacting Binaries in the Old Open Cluster NGC 6791
Verbunt, Frank; Bedin, Luigi R.; Belloni, Tomaso +3 more
We present the first X-ray study of NGC 6791, one of the oldest open clusters known (8 Gyr). Our Chandra observation is aimed at uncovering the population of close interacting binaries down to L X ≈ 1 × 1030 erg s-1 (0.3-7 keV). We detect 86 sources within 8' of the cluster center, including 59 inside the half-mass…
Galactic kinematics from a sample of young massive stars
Bobylev, V. V.; Bajkova, A. T.
Based on published sources, we have created a kinematic database on 220 massive (> 10 M ⊙) young Galactic star systems located within ≤3 kpc of the Sun. Out of them, ≈100 objects are spectroscopic binary and multiple star systems whose components are massive OB stars; the remaining objects are massive Hipparcos B stars with parallax …
Gradients of Stellar Population Properties and Evolution Clues in a Nearby Galaxy M101
Kong, Xu; Zou, Hu; Lin, Lin +5 more
Multiband photometric images from ultraviolet and optical to infrared are collected to derive spatially resolved properties of the nearby Scd-type galaxy M101. With evolutionary stellar population synthesis models, two-dimensional distributions and radial profiles of age, metallicity, dust attenuation, and star formation timescale in the form of t…
CO rotational line emission from a dense knot in Cassiopeia A. Evidence for active post-reverse-shock chemistry
Rho, Jeonghee; Black, John H.; Berné, Olivier +6 more
We report a Herschel detection of high-J rotational CO lines from a dense knot in the supernova remnant Cas A. Based on a combined analysis of these rotational lines and previously observed ro-vibrational CO lines, we find the gas to be warm (two components at ~400 and 2000 K) and dense (106-7 cm-3), with a CO column density …
Fundamental parameters of bright Ap stars from wide-range energy distributions and advanced atmospheric models
Shulyak, D.; Ryabchikova, T.; Kochukhov, O.
Aims: As a well-established procedure for the vast majority of normal main-sequence stars, determination of atmospheric and stellar parameters turns to be a challenging process in case of magnetic chemically peculiar stars. Inhomogeneous distribution of chemical elements and strong magnetic fields make most of the standard photometric and spe…
Merger shocks in Abell 3667 and the Cygnus A cluster
Finoguenov, A.; Wik, D. R.; Sarazin, C. L.
We present new XMM-Newton observations of the northwest (NW) radio relic region in the cluster Abell 3667. We detect a jump in the X-ray surface brightness and X-ray temperature at the sharp outer edge of the radio relic which indicate that this is the location of a merger shock with a Mach number of about 2. Comparing the radio emission to the sh…
The XMM-Newton/EPIC X-Ray Light Curve Analysis of WR 6
Hamann, W. -R.; Oskinova, L. M.; Ignace, R. +4 more
We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the w…
Unusual Filaments inside the Umbra
Sainz Dalda, A.; Kleint, L.
We analyze several unusual filamentary structures which appeared in the umbra of one of the sunspots in AR 11302. They do not resemble typical light bridges in morphology or in evolution. We analyze data from SDO/HMI to investigate their temporal evolution, Hinode/SP for photospheric inversions, IBIS for chromospheric imaging, and SDO/AIA for the …
X-ray source variability study of the M 31 central field using Chandra HRC-I
Della Valle, M.; Pietsch, W.; Haberl, F. +5 more
Context. The central field of the Andromeda galaxy (M 31) was monitored from 2006 to 2012 using the Chandra HRC-I detector (about 0.1-10 keV energy range) with the main aim of detecting X-rays from optical novae. We present a systematic analysis of all X-ray sources found in the 41 nova monitoring observations, along with 23 M 31 central field HRC…
The Origin of the 3.4 µm Feature in Wild 2 Cometary Particles and in Ultracarbonaceous Interplanetary Dust Particles
Matrajt, G.; Flynn, G.; Brownlee, D. +2 more
We analyzed two ultracarbonaceous interplanetary dust particles (IDPs) and two cometary Wild 2 particles with infrared spectroscopy. We characterized the carrier of the 3.4 µm band in these samples and compared its profile and the CH2/CH3 ratios to the 3.4 µm band in the diffuse interstellar medium (DISM), in the …