Search Publications
Spatially resolved optical spectroscopy of the Herbig Ae/Vega-like binary star HD 35187
Crawford, I. A.; Dunkin, S. K.
We report on observations of the young binary system HD 35187 (SAO 77144). For the first time, we have obtained spatially resolved optical spectra of the individual stars. Analysis of their effective temperatures indicates that the stars have spectral types of A2 (HD 35187B) and A7 (HD 35187A). Analysis of the Hγ Balmer line indicates a luminosity…
A double-frequency dwarf nova oscillation in OY CAR
Horne, Keith; Marsh, T. R.
We have detected coherent oscillations (`dwarf nova oscillations') in Hubble Space Telescope spectra of the dwarf nova OY Car. The oscillations were seen towards the end of a superoutburst of OY Car. The oscillations are extraordinary compared with the many other examples in the literature for two reasons. First, their amplitude is large, with a p…
CCD photometry of variable stars in the Magellanic Clouds - V. The eclipsing binaries HV1620 and HV2241
Guinan, E. F.; Pritchard, J. D.; Tobin, W. +1 more
Using improved techniques, high-quality CCD uvbyVI_C photometry has been obtained for the 14th magnitude eclipsing binaries HV1620 in the Small Magellanic Cloud (SMC) and HV2241 in the Large Magellanic Cloud (LMC). IUE ultraviolet spectrophotometry was also obtained. These data have been analysed using the Wilson & Devinney synthetic light-cur…
Evolution of the near-infrared in rich galaxy clusters
Mobasher, Bahram; Trentham, Neil
We present the K-band (2.2 µm) luminosity functions (LFs) of the X-ray-luminous clusters MS1054-0321 (z=0.823), MS0451-0305 (z=0.55), Abell 963 (z=0.206), Abell 665 (z=0.182) and Abell 1795 (z=0.063) down to absolute magnitudes M_K=-20. Our measurements probe fainter absolute magnitudes than do any previous studies of the near-infrared LFs o…
An alternative explanation of the EUV spectrum of the white dwarf G191-B2B invoking a stratified H+He envelope including heavier elements
Barstow, M. A.; Hubeny, I.
Only recently has it been possible to find an effective temperature and composition for the hot DA white dwarf G191-B2B which can consistently match the optical, far-UV and EUV data simultaneously, by using new non-LTE model calculations that include the effects of line blanketing from more than 9 million (mainly Fe and Ni) transitions. However, t…
Dark haloes of spiral galaxies: ISO photometry
Gilmore, Gerard; Unavane, M.
We exclude hydrogen-burning stars, of any mass above the hydrogen-burning limit and any metallicity, as significant contributors to the massive haloes deduced from rotation curves to dominate the outer parts of spiral galaxies. We present and analyse images of four nearly edge-on bulgeless spiral galaxies (UGC 711, NGC 2915, UGC 12426, UGC 1459) o…
Ultraviolet images of the gravitationally lensed quadruple quasar Q2237+0305 with the HST WFPC2
Turner, Edwin L.; Blanton, Michael; Wambsganss, Joachim
We present and analyse observations of the quadruple lensed quasar Q2237+0305, obtained with the HST WFPC2 camera in the F336W and F300W filters. 25 exposures were performed within 15h real time on 1995 November 3. On a time-scale of 3-4h, we observe no variation in component A greater than 0.02 mag. The other components remain constant over a per…
The lower main sequence of the globular cluster M3 with the Hubble Space Telescope: luminosity and mass functions
Montegriffo, P.; Paresce, F.; de Marchi, G. +6 more
We present HST observations of the lower main sequence of the Galactic globular cluster M3. Our data, obtained with WFPC2 in the F814W and F555W filters, sample a region centred about 4 arcmin away from the cluster centre (at ~4.2 core radii). The photometry of the WF2, WF3 and WF4 fields extends down to V~26.5 (I~25), much deeper than any previou…
HIPPARCOS absolute magnitudes for metal-rich K giants and the calibration of DDO photometry
Flynn, Chris; Hog, Erik
Parallaxes for 581 bright K giants have been determined using the Hipparcos satellite. We combine the trigonometric parallaxes with ground-based photometric data to determine the K giant absolute magnitudes. For all these giants, absolute magnitude estimates can also be made using the intermediate-band photometric David Dunlop Observatory (DDO) sy…
Repetitive structure in the stellar wind of HD 93843: a normal O-type star
Howarth, Ian D.; Massa, Derck; Prinja, Raman K. +1 more
We present the results from a 28-day IUE time-series campaign monitoring the stellar wind of the O5-type giant HD 93843. The principal aim was to study variability in the wind of a star with a normal projected rotation velocity. Systematic changes are identified, amidst continuous line-profile variability, in the absorption troughs of the Siiv and…