Search Publications
Classification of X-Ray Sources in the XMM-Newton Serendipitous Source Catalog: Objects of Special Interest
Lin, Dacheng; Webb, Natalie A.; Barret, Didier
We analyze 18 sources that showed interesting properties of periodicity, very soft spectra, and/or large long-term variability in X-rays in our project of classification of sources from the 2XMMi-DR3 catalog, but were poorly studied in the literature, in order to investigate their nature. Two hard sources show X-ray periodicities of ~1.62 hr (2XMM…
Evolution from protoplanetary to debris discs: the transition disc around HD 166191
Ménard, F.; Sitko, M. L.; Wyatt, M. C. +12 more
HD 166191 has been identified by several studies as hosting a rare and extremely bright warm debris disc with an additional outer cool disc component. However, an alternative interpretation is that the star hosts a disc that is currently in transition between a full gas disc and a largely gas-free debris disc. With the help of new optical to mid-i…
A Far-IR View of the Starburst-driven Superwind in NGC 2146
Murphy, E. J.; Armus, L.; Hunt, L. K. +19 more
NGC 2146, a nearby luminous infrared galaxy, presents evidence for outflows along the disk minor axis in all gas phases (ionized, neutral atomic, and molecular). We present an analysis of the multi-phase, starburst-driven superwind in the central 5 kpc as traced in spatially resolved spectral line observations, using far-IR Herschel PACS spectrosc…
On the shape and motion of the Earth's bow shock
Meziane, K.; Hamza, A. M.; Alrefay, T. Y.
Multipoint-measurements by the magnetic field Cluster-FGM (Flux Gate Magnetometer) are used to determine the local shock normal, and in turn allow the study of shock location shape and the velocity of the Earth's bow shock. The shock crossings cover orbits in which the spacecraft separation is of the order of ~600 km or less. A data selection of 1…
Stellar content and distances to the isolated spiral galaxies NGC 6503 and NGC 6946
Tikhonov, N. A.
Based on archival Hubble Space Telescope images, we have performed stellar photometry of several fields in the isolated spiral galaxies NGC 6503 and NGC 6946 with high peculiar velocities. Based on the TRGB method, we have determined the distances to the galaxies: D = 6.30 ± 0.10 Mpc for NGC 6503 and D = 6.72 ± 0.15 Mpc for NGC 6946. The current s…
The tension on the cosmological parameters from different observational data
Gao, Qing; Gong, Yungui
Planck measurements of the cosmic microwave background power spectra find a lower value of the Hubble constant H0 and a higher value of the fractional matter energy density Ωm0 for the concordance ΛCDM model, and these results are in tension with other measurements. The Planck group argued that the tension came either from so…
The EUV spectrum of the Sun: SOHO CDS NIS radiances during solar cycle 23
Andretta, V.; Del Zanna, G.
For the first time, we present and discuss EUV radiances of the solar transition region (TR) and corona obtained during a solar cycle. The measurements were obtained with the SOHO/coronal diagnostic spectrometer (CDS) during the period from 1996 to 2010. We find that limb-brightening significantly affects any characterisation of the solar radiance…
Application of the new comprehensive X-ray spectral model to the two brightest intermediate polars EX Hydrae and V1223 Sagittarii
Ishida, Manabu; Hayashi, Takayuki
We applied the new comprehensive X-ray spectral model for the post-shock accretion column (PSAC) of the intermediate polars (IPs) constructed by Hayashi and Ishida to the Suzaku data of the two brightest IPs EX Hydrae and V1223 Sagittarii. The white dwarf (WD) mass and the specific accretion rate of EX Hya are estimated to be M_WD= 0.63_{-0.14}^{+…
High-energy Emission of the First Millisecond Pulsar
Cheng, K. S.; Takata, J.; Ng, C. -Y. +2 more
We report on X-ray and gamma-ray observations of the millisecond pulsar (MSP) B1937+21 taken with the Chandra X-ray Observatory, XMM-Newton, and the Fermi Large Area Telescope. The pulsar X-ray emission shows a purely non-thermal spectrum with a hard photon index of 0.9 ± 0.1, and is nearly 100% pulsed. We found no evidence of varying pulse profil…
Constraining the Disk Masses of the Class I Binary Protostar GV Tau
Sheehan, Patrick D.; Eisner, Josh A.
We present new spatially resolved 1.3 mm imaging with CARMA of the GV Tau system. GV Tau is a Class I binary protostar system in the Taurus Molecular Cloud, the components of which are separated by 1.''2. Each protostar is surrounded by a protoplanetary disk, and the pair may be surrounded by a circumbinary envelope. We analyze the data using deta…