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Detection of Absorption Features in the X-Ray Spectrum of the Narrow-Line Quasar PG 1404+226: Possible Evidence of Accretion Disk Winds
Rao, A. R.; Dewangan, G. C.; Dasgupta, Surajit +1 more
We present the results of an analysis of data from XMM-Newton and Chandra observations of the high-luminosity narrow-line quasar PG 1404+226. We confirm a strong soft X-ray excess in the X-ray spectrum, and we find rapid variability (a factor of 2 in about 5000 s). When the X-ray spectrum is fitted with a two-component model that includes a power-…
Optical Sources near the Bright X-Ray Source in NGC 1073
Kaaret, Philip
New HST observations show that the bright X-ray source in the face-on spiral galaxy NGC 1073 is located near a ring of recent star formation with an age of 8-16 Myr. This strengthens the association of X-ray sources in spiral galaxies emitting near or above the Eddington limit for a 20 Msolar black hole with recent star formation events…
X-ray spectral and timing characteristics of the stars in the young open cluster IC 2391
Micela, G.; Peres, G.; Sciortino, S. +2 more
We present X-ray spectral and timing analysis of members of the young open cluster IC 2391 observed with the XMM-Newton observatory. We detected 99 X-ray sources by analysing the summed data obtained from MOS1, MOS2 and pn detectors of the EPIC camera; 24 of them are members, or probable members, of the cluster. Stars of all spectral types have be…
Direct Evidence for a Polar Spot on SV Camelopardalis
Jeffers, S. V.; Collier Cameron, A.; Barnes, J. R. +2 more
We have used spectrophotometric data from the Hubble Space Telescope (HST) to eclipse-map the primary component of the RS CVn binary SV Cam over nine HST orbits. We find from these observations and the Hipparcos parallax that the surface flux in the eclipsed low-latitude region of the primary is about 30% lower than that computed from a PHOENIX mo…
Forward modeling of coronal funnels
Peter, H.; Aiouaz, T.; Keppens, R.
We propose a forward modeling approach of coronal funnels to investigate the outer layers of the solar atmosphere with respect to their thermodynamical properties and resulting emission line spectra. We investigate the plasma flow out of funnels with a new 2D MHD time dependent model including the solar atmosphere all the way from the chromosphere…
A universal characteristic of type II radio bursts
Kaiser, M. L.; Gopalswamy, N.; Aguilar-Rodriguez, E. +2 more
We present a study on the spectral properties of interplanetary type II radio bursts observed by the Radio and Plasma Wave (WAVES) experiment on board the Wind spacecraft. We investigated the relative bandwidth of the type II radio bursts observed by WAVES from 1997 up to 2003. We obtained three sets of events, based on the frequency domain of occ…
The Double-Peak Spectral Energy Density of Gamma-Ray Bursts and the True Identity of GRB 031203
Dar, Arnon; Dado, Shlomo
A double-peak spectral energy density of prompt γ-rays, similar to that observed in blazars, is expected in the cannonball (CB) model of gamma-ray bursts (GRBs) produced in supernova (SN) explosions. The first sub-MeV ordinary peak is formed by inverse Compton scattering (ICS) of the ambient SN light by the CBs' electrons, while the second peak at…
XMM-Newton observations of β Centauri (B1 III): The temperature structure in the hot plasma and the photosphere-wind connection
Raassen, A. J. J.; Mewe, R.; Cassinelli, J. P. +2 more
We present XMM-Newton observations of the B giant β Centauri (B1 III). The spectra are rich of spectral lines from a wide range of ionization stages which indicate temperatures in the range ~0.1-0.6 keV. Simultaneous fits to the rgs, epic-mos, and epic-pn spectra yield three plasma temperatures (0.1, 0.2, and 0.6 keV), emission measures, and eleme…
Internal colour gradients for E/S0 galaxies in Abell 2218
Driver, Simon P.; De Propris, Roberto; Colless, Matthew +2 more
We determine colour gradients of -0.15 +/- 0.08 mag per decade in radius in F450W-F606W and -0.07 +/- 0.06 mag per decade in radius in F606W-F814W for a sample of 22 E/S0 galaxies in Abell 2218. These gradients are consistent with the existence of a mild (~-0.3 dex per decade in radius) gradient in metal abundance (cf. previous work at lower and h…
Relating White-Light Coronal Images to Magnetic Fields and Plasma Flow
Woo, Richard
The solar magnetic field is key to a detailed understanding of the Sun's atmosphere and its transition to the solar wind. However, the lack of detailed magnetic field measurements everywhere except at the photosphere has made it challenging to determine its topology and to understand how it produces the observed plasma properties of the corona and…