Search Publications
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…
Observation of energy-time dispersed ion structures in the magnetosheath by CLUSTER: possible signatures of transient acceleration processes at shock
Budnik, E.; Balogh, A.; Dandouras, I. +11 more
We analyse energy-time dispersed ion signatures that have been observed by CLUSTER in the dayside magnetosheath. These events are characterized by sudden increases in the ion flux at energies larger than 10 keV. The high energy ions (30 keV) are first detected, with the transition to the low energy ions (5 keV) lasting about 100 s. These injection…
Transport of a few-MEV jovian and galactic electrons at solar maximum
Ferreira, S. E. S.; Potgieter, M. S.; Heber, B. +2 more
The heliospheric modulation of galactic and jovian electrons is studied using a three-dimensional, steady-state model based on Parker's transport equation including the jovian source. The model is developed to study both jovian and galactic electrons. It is illustrated how the electron intensity-time profile along the Ulysses trajectory is effecte…
Distinct shock acceleration processes — Evaluation of the magnetic trap dimensions formed upstream of an interplanetary shock using measurements of the ulysses spacecraft
Sarris, E. T.; Anagnostopoulos, G. C.; Marhavilas, P. K. +1 more
We analyze the acceleration signatures of energetic ions (E > 50 keV) and electrons (E > 30 keV) being observed on day 256 of the year 1992 UT, in the vicinity of the surface of a fast-mode quasi-perpendicular interplanetary hydromagnetic shock, using fine time resolution measurements by the HI-SCALE instrument onboard the Ulysses spacecraft…