Search Publications
Missions
Journals
Publication Years
The far-infrared signature of dust in high-latitude regions
del Burgo, C.; Ábrahám, P.; Laureijs, R. J. +1 more
We present ISOPHOT observations of eight interstellar regions in the 60-200 µm wavelength range. The regions belong to mostly quiescent high-latitude clouds and have optical extinction peaks from AV~1-6 mag. From the 150- and 200-µm emission, we derived colour temperatures for the classical big grain component which show a c…
Three-dimensional photoionization modelling of the planetary nebula NGC 3918
Morisset, C.; Barlow, M. J.; Liu, X. -W. +2 more
The three-dimensional Monte Carlo photoionization code MOCASSIN has been applied to construct a realistic model of the planetary nebula NGC 3918. Three different geometric models were tried, the first being the biconical density distribution already used some years ago by Clegg et al. In this model the nebula is approximated by a biconical structu…
New results on GP Com
Marsh, T. R.; Steeghs, D.; Morales-Rueda, L. +3 more
We present high resolution optical and UV spectra of the 46 min orbital period, helium binary, GP Com. Our data contains simultaneous photometric correction which confirms the flaring behaviour observed in previous optical and UV data. In this system all lines show a triple peaked structure where the outer two peaks are associated with the accreti…
A Luminous Recurrent Supersoft X-Ray Source in NGC 300
Kong, A. K. H.; Di Stefano, R.
We report the results of XMM-Newton observations for an especially luminous supersoft X-ray source (SSS) with a bolometric luminosity of 1039 ergs s-1 in the spiral galaxy NGC 300. The source was detected as an SSS in 1992 and disappeared in subsequent X-ray observations. The source was active again during recent XMM-Newton o…
More nitrogen rich B-type stars in the SMC cluster, NGC 330
Dufton, P. L.; Lennon, D. J.; Crowley, C.
High resolution spectra of seven early B-type giant/supergiant stars in the SMC cluster NGC 330 are analysed to obtain their chemical compositions relative to SMC field and Galactic B-type stars. It is found that all seven stars are nitrogen rich with an abundance approximately 1.3 dex higher than an SMC main-sequence field B-type star, AV304. The…
The Compact Nucleus of the Deep Silicate Absorption Galaxy NGC 4418
Scoville, N. Z.; Matthews, K.; Soifer, B. T. +6 more
High-resolution Hubble Space Telescope (HST) near-infrared and Keck mid-infrared images of the heavily extinguished infrared-luminous galaxy NGC 4418 are presented. These data make it possible to observe the imbedded near-infrared structure on scales of 10-20 pc and to constrain the size of the mid-infrared-emitting region. The 1.1-2.2 µm da…
The First Detection of Spatially Resolved Mid-Infrared Scattered Light from a Protoplanetary Disk
Duchêne, G.; Ghez, A. M.; McCabe, C.
We report spatially resolved 11.8 µm images, obtained at the W. M. Keck 10 m telescope, of the protoplanetary disk around the pre-main-sequence star HK Tau B. The mid-infrared morphology and astrometry of HK Tau B with respect to HK Tau A indicate that the flux observed in the mid-infrared from HK Tau B has been scattered off the upper surfa…
The origin of the iron lines in NGC 7213
Perola, G. C.; Bianchi, S.; Balestra, I. +1 more
The analysis of a simultaneous XMM-Newton/BeppoSAX plus three previous BeppoSAX observations revealed that NGC 7213 is a rather peculiar Seyfert 1. No significant Compton reflection component was observed, while an iron line complex, best explained in terms of three narrow lines, is clearly apparent in the data. Due to the absence of the reflectio…
Far-Ultraviolet Emission from Elliptical Galaxies at z = 0.33
Ferguson, Henry C.; Brown, Thomas M.; Rich, R. Michael +4 more
We present far-UV images of the rich galaxy cluster ZwCl 1358.1+6245, taken with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope (HST). When combined with archival HST observations, our data provide a measurement of the UV-to-optical flux ratio in eight early-type galaxies at z=0.33. Because the UV flux originates in a…
A Far-Ultraviolet Survey of 47 Tucanae. II. The Long-Period Cataclysmic Variable AKO 9
Zurek, David R.; Gilliland, Ronald L.; Shara, Michael M. +2 more
We present time-resolved far-ultraviolet (FUV) spectroscopy and photometry of the 1.1 day eclipsing binary system AKO 9 in the globular cluster 47 Tucanae. The FUV spectrum of AKO 9 is blue and exhibits prominent C IV and H II emission lines. The spectrum broadly resembles that of long-period cataclysmic variables (CVs) in the Galactic field. Comb…