Search Publications
Iron line spectroscopy of NGC 4593 with XMM-Newton: where is the black hole accretion disc?
Kaiser, Mary Elizabeth; Brenneman, Laura W.; Wilms, Jörn +1 more
We present an analysis of the 2-10 keV XMM-Newton/EPIC-pn spectrum of the Seyfert-1 galaxy NGC 4593. Apart from the presence of two narrow emission lines corresponding to the Kα lines of cold and hydrogen-like iron, this spectrum possesses a power-law form to within ~3-5 per cent. There is a marked lack of spectral features from the relativistic r…
Flow shear near the boundary of the plasma sheet observed by Cluster and Geotail
Balogh, A.; RèMe, H.; Fazakerley, A. N. +13 more
We report on the transient strong flow shear (large northward/southward electric field) events accompanied by energetic ion beams and localized field-aligned currents observed at the boundary of the premidnight plasma sheet by Cluster in the Northern Hemisphere and Geotail in the Southern Hemisphere. The events took place associated with plasma sh…
XMM-Newton confirmation of a warm absorber in the z= 4.4 blazar PMN J0525-3343
Iwasawa, K.; Fabian, A. C.; Celotti, A. +2 more
We present the analysis and results from a series of XMM-Newton observations of the distant blazar PMN J0525-3343 at a redshift of 4.4. The X-ray spectrum shows a spectral flattening below ~1 keV, confirming earlier results from ASCA and BeppoSAX. The spectrum is well fitted by a power-law continuum with either a spectral break or absorption; no s…
A young binary brown dwarf in the R-CrA star formation region
Demarco, R.; Martín, E. L.; Bouy, H. +5 more
We present imaging and spectroscopic observations with HST (WFPC2, ACS/HRC and STIS), VLT (FORS2) and Keck (HIRES) of the dM 8 ultra-cool dwarf
Period-luminosity relations for Galactic Cepheid variables with independent distance measurements
Ngeow, Chow-Choong; Kanbur, Shashi M.
In this paper, we derive the period-luminosity (PL) relation for Galactic Cepheids with recent independent distance measurements from open cluster, Barnes-Evans surface brightness, interferometry and Hubble Space Telescope astrometry techniques. Our PL relation confirms the results from recent works, which showed that the Galactic Cepheids follow …
XMM-Newton spectral and timing analysis of the faint millisecond pulsars PSR J0751+1807 and PSR J1012+5307
Kramer, M.; Webb, N. A.; Barret, D. +3 more
We present XMM-Newton MOS imaging and PN timing data of the faint millisecond pulsars
Locating the Warm--Hot Intergalactic Medium in the Simulated Local Universe
Ishida, Manabu; Dolag, Klaus; Ohashi, Takaya +11 more
We present an analysis of mock spectral observations of warm-hot intergalactic medium (WHIM) using a constrained simulation of the local universe. The simulated map of oxygen emission lines from local WHIM well reproduces the observed structures traced by galaxies in the real local universe. We further attempt to perform mock observation of the ou…
On Star Effective Temperatures and H II Region Ionization Parameter Gradients in the Galaxy
Morisset, C.
Extensive photoionization model grids are computed for single-star H II regions using stellar atmosphere models from the WM-Basic code. Mid-IR emission-line intensities are predicted, and diagnostic diagrams of [Ne III/II] and [S IV/III] excitation ratios are built, taking into account the metallicities of both the star and the H II region. The di…
PSR B1951+32: A Bow Shock-confined X-Ray Nebula, a Synchrotron Knot, and an Optical Counterpart Candidate
Chatterjee, S.; Cordes, J. M.; Gallant, Y. A. +7 more
The radio pulsar PSR B1951+32 and the supernova remnant CTB 80 provide a rich laboratory for the study of neutron stars and supernova remnants. Here, we present ground-based optical and near-infrared observations of them, along with X-ray observations with Chandra and a reanalysis of archival data obtained with the Hubble Space Telescope. The X-ra…
New membership determination and proper motions of NGC 1817. Parametric and non-parametric approach
Jordi, C.; Balaguer-Núñez, L.; Galadí-Enríquez, D. +1 more
We have calculated proper motions and re-evaluated the membership probabilities of 810 stars in the area of two NGC objects, NGC 1817 and NGC 1807. We have obtained absolute proper motions from 25 plates in the reference system of the Tycho-2 Catalogue. The plates have a maximum epoch difference of 81 years; and they were taken with the double ast…