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XMM-Newton Observation of Fe Kα Emission from a Broad Absorption Line Quasar: Markarian 231
Turner, T. J.; Kraemer, S. B.
We present results from a 20 ks XMM-Newton observation of Mrk 231. The European Photon Imaging Camera (EPIC) spectral data reveal strong line emission due to Fe Kα, which has rarely been detected in this class, as broad absorption line quasars (BAL QSOs) are very faint in the X-ray band. The line energy is consistent with an origin in neutral Fe. …
Optimal Masks for Solar g-Mode Detection
Kosovichev, A. G.; Scherrer, P. H.; Schou, J. +1 more
The detection of gravity (g) modes of solar oscillations is important for probing the physical conditions in the Sun's energy-generating core. We have developed a new method of spatial masks optimized to reveal solar g-modes of angular degree l=1-3 and applied it to Michelson Doppler Imager data in the frequency range of 50-500 µHz. These ma…
Atomic Data and Spectral Line Intensities for Si VII
Bhatia, A. K.; Landi, E.
Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for the Si VII configurations 2s22p4, 2s2p5, 2p6, 2s22p33s, 2s22p33p, and 2s22p33d, giving rise to 86 fine-struc…
Galaxy Threshing and Ultra-Compact Dwarfs in the Fornax Cluster
Ferguson, Henry C.; Phillipps, Steven; Drinkwater, M. J. +3 more
We have discovered a new type of galaxy in the Fornax Cluster: `ultra-compact' dwarfs (UCDs). The UCDs are unresolved in ground-based imaging and have spectra typical of old stellar systems. Although the UCDs resemble overgrown globular clusters, based on VLT UVES echelle spectroscopy, they appear to be dynamically distinct systems with higher int…
Spectral response of the pulsationally induced shocks in the atmosphere of BW Vulpeculae
Smith, Myron A.; Jeffery, C. Simon
BW Vulpeculae (BW Vul) is remarkable for exciting an extremely strong radial pulsation mode which grows through its outer envelope and forms visible shock features in the atmosphere. Material propelled upwards by the shock returns violently to the lower photosphere where it creates a second shock just before the start of the next cycle. We have ob…
The XMM-Newton Survey Science Centre Medium Sensitivity Survey
Pérez-Fournon, I.; Page, M. J.; Barcons, X. +5 more
We present preliminary results on the XMM-Newton Survey Science Centre medium sensitivity survey, with 0.5-4.5 keV flux limit 2x 10-14 erg cm-2 s-1. At present, 19 fields have been examined with a total of 239 X-ray sources. Identifications for about 2/3 of these reveal that type 1 AGN dominate, but type 2 AGN, abs…
HST/WFPC2 snapshot imaging of symbiotic stars
Eyres, S. P. S.; Bode, M. F.; Brocksopp, C.
The results of a HST/WFPC2 snapshot imaging survey of selected symbiotic stars in 1999/2000 are presented. Seven sources - HD 149427 (PC 11), PU Vul, RT Ser, He2-104 (Southern Crab), V1329 Cyg (HBV 475), V417 Cen and AS 201 - were observed in filters F218W (ultraviolet continuum), F502N ([O III]λλ 4959, 5007) and F656N (Hαλ 6563); an eighth source…
Far and mid infrared observations of two ultracompact H II regions and one compact CO clump
Ghosh, S. K.; Mookerjea, B.; Verma, R. P. +1 more
Two ultracompact H II regions (IRAS 19181+1349 and 20178+4046) and one compact molecular clump (20286+4105) have been observed at far infrared wavelengths using the TIFR 1 m balloon-borne telescope and at mid infrared wavelengths using ISO. Far infrared observations have been made simultaneously in two bands with effective wavelengths of ~ 150 and…
The radio signature of twisted magnetic ropes and reconnection site in the low corona
Grechnev, V. V.; Huang, G. L.; Altyntsev, A. T. +2 more
A solar radio burst on 25 August 1999 with fine structures (FS) at 4.5-7.5 GHz is studied in this paper. The FS started about one minute prior to the main burst. The maximum emission took place at 4-5 GHz for the FS, and at 10-11 GHz for the main burst, respectively. The time profiles at 4.5-7.5 GHz coincide very well with those of hard X-rays (fr…
Modeling solar and stellar flares
Reale, F.
The thermal phase of solar X-ray flares has been described as heating-triggered evolution of plasma confined in coronal loops. This paper describes how the modeling of the thermal phase of spatially resolved solar X-ray flares has been extended to investigate spatially unresolved stellar X-ray flares with different scopes, aims and perspectives. H…