Search Publications
Missions
Journals
Publication Years
XMM-Newton Observations of PSR B1706-44
Cropper, M.; McGowan, K. E.; Kennea, J. A. +5 more
We report on the XMM-Newton observations of the young 102 ms pulsar PSR B1706-44. We have found that both a blackbody plus power law and a magnetized atmospheric model plus power law provide an excellent fit to the European Photon Imaging Camera (EPIC) spectra. The two scenarios are therefore indistinguishable on a statistical basis, although we a…
An HST parallax of the distant cataclysmic variable V1223 Sgr, its system parameters, and accretion rate
Gänsicke, B. T.; Beuermann, K.; McArthur, B. E. +2 more
Using the Hubble space Telescope Fine Guidance Sensor, we have measured the trigonometric parallax of the bright cataclysmic variable 1223 Sgr. The absolute parallax is πabs= 1.96± 0.18 mas, making V1223 Sgr the most distant CV with a well-determined trigonometric parallax. This distance, a Lutz-Kelker correction, and the previously mea…
The soft X-ray absorption lines of the Seyfert 1 galaxy MCG-6-30-15
Vaughan, S.; Fabian, A. C.; Lee, J. C. +1 more
The absorption lines in the soft X-ray spectrum of MCG-6-30-15 are studied using the reflection grating spectrometer data from the 2001 XMM-Newton 320-ks observation. A line search of the full time-averaged spectrum reveals 51 absorption lines and one emission line. The equivalent widths of the lines are measured and the majority of the lines iden…
The Dynamical Distance to M15: Estimates of the Cluster's Age and Mass and of the Absolute Magnitude of Its RR Lyrae Stars
Baumgardt, H.; Harrison, T. E.; McNamara, B. J.
Newly determined high-precision relative proper motions determined from the Hubble Space Telescope Wide Field Planetary Camera 2 are used along with radial velocity measurements to determine the dynamical distance to the globular cluster M15. A comparison of the proper motion and radial velocity dispersions from a sample of 237 stars, located at a…
Non-LTE Radiative Transfer in Model Prominences. I. Integrated Intensities of He I Triplet Lines
Labrosse, N.; Gouttebroze, P.
In this work we use new results of radiative transfer calculations out of local thermodynamical equilibrium to study the triplet lines emitted by neutral helium in solar quiescent prominences. We compare two types of prominence atmospheres: isothermal and isobaric models versus nonisothermal and nonisobaric ones. We can thus investigate the effect…
Correlated Infrared and X-ray variability of the transient Anomalous X-ray Pulsar XTE J1810-197
Covino, S.; Campana, S.; Tiengo, A. +10 more
We report on observations aimed at searching for flux variations from the proposed IR counterpart of the Anomalous X-ray Pulsar (AXP) XTE J1810-197. These data, obtained in March 2004 with the adaptive optics camera NAOS-CONICA at the ESO VLT, show that the candidate proposed by Israel et al. (\cite{Israel04}, ApJ, 603, L97) was fainter by Δ H=0.7…
Age Constraints for an M31 Globular Cluster from Main-Sequence Photometry
Ferguson, Henry C.; Brown, Thomas M.; Rich, R. Michael +5 more
We present a color-magnitude diagram (CMD) of the globular cluster SKHB 312 in the Andromeda galaxy (M31), obtained with the Advanced Camera for Surveys on the Hubble Space Telescope. The cluster was included in deep observations taken to measure the star formation history of the M31 halo. Overcoming a very crowded field, our photometry of SKHB 31…
Magnetic Field Confinement in the Solar Corona. I. Force-free Magnetic Fields
Low, B. C.; Thomas, S.; Flyer, N. +1 more
Axisymmetric force-free magnetic fields external to a unit sphere are studied as solutions to boundary value problems in an unbounded domain posed by the equilibrium equations. It is well known from virial considerations that stringent global constraints apply for a force-free field to be confined in equilibrium against expansion into the unbounde…
Obscured Star Formation in the Central Region of the Dwarf Galaxy NGC 5253
Imanishi, Masatoshi; Rieke, George H.; Alonso-Herrero, Almudena +4 more
We present Hubble Space Telescope (HST) NICMOS observations (1.1-2.2 µm) and 1.9-4.1 µm spectroscopy of the central region of the dwarf galaxy NGC 5253. The HST NICMOS observations reveal the presence of a nuclear double star cluster separated by ~=0.3"-0.4", or 6-8 pc (for a distance d=4.1 Mpc). The double star cluster, also a bright …
Modeling temporal variability of plasma conditions in the Io torus during the Cassini era
Delamere, P. A.; Bagenal, F.; Steffl, A.
Observations of ultraviolet (UV) emissions from the major ion species (S+, S++, S+++, O+, O++) of the Io plasma torus made during the Cassini flyby (October 2000 to March 2001) have revealed significant time variability. Using a homogeneous model for mass and energy flow in the torus parameter…