Search Publications
Properties of dust and detection of Hα emission in LDN 1780
del Burgo, C.; Cambrésy, L.
We present ISOPHOT observations between 60 and 200µm and a near-infrared extinction map of the small intermediate-density cloud Lynds Dark Nebula (LDN) 1780 (Galactic coordinates l = 359° and b = 36.8°). For an angular resolution of 4arcmin, the visual extinction maximum is AV = 4.4mag. We have used the ISOPHOT data together with …
Ultraviolet variability of the magnetic chemically peculiar star 56 Arietis
Sokolov, N. A.
The spectrophotometric variability of the magnetic chemically peculiar star 56 Arietis (56 Ari) in the far-ultraviolet spectral region from 1150 to 1980 Å is investigated. This study is based on the archival International Ultraviolet Explorer data obtained at different phases of the rotational cycle. The brightness of 56 Ari is not constant in the…
Absolute parameters of the Algol binary V505 Sgr from infrared JK light curves
Arévalo, M. J.; Lázaro, C.; Antonopoulou, E.
We present the first light curves of V505 Sgr in the infrared (IR) J and K bands. The light curves are analysed with a code based on Roche geometry and stellar model atmosphere fluxes in order to determine a new set of stellar and orbital parameters. From the visual-IR photometry we find no evidence of IR excess in the system. We study the effect …
XMM-Newton and Chandra observations of the ultra-compact binary RX J1914 + 24
Cropper, Mark; Ramsay, Gavin; Hakala, Pasi
The nature of the X-ray source RX J1914 + 24 has been the subject of much debate. It shows a prominent period of 569 s in X-rays and the optical/infrared: in most models this has been interpreted as the binary orbital period. We present our analysis of new XMM-Newton and Chandra data. We find a longer term trend in the XMM-Newton data and power at…
Inner-shell ionization, radiative losses and thermal conductivity in young SNRs
Kosenko, D. I.
Self-consistent treatment of time-dependent ionization in hydrodynamical calculations of the X-ray emission from young supernova remnants (SNRs) has been performed. The novel feature of the calculations is that Kα lines from species produced by inner-shell collisional ionization are included. Parameters of the shocked ejecta are found from fitting…
Photoelectric radial velocities, Paper XVII The orbits of 30 spectroscopic binaries in the southern Clube Selected Areas
Griffin, R. F.
Three of the six southern Clube Areas that were mainly observed at the European Southern Observatory and whose principal results are given in Paper XVI are marginally observable from Haute-Provence. Additional measurements obtained on several observing runs there enabled orbits to be determined (in most cases rather poorly, owing to the paucity of…
Hubble Space Telescope observations of SV Cam - II. First derivative light-curve modelling using PHOENIX and ATLAS model atmospheres
Jeffers, S. V.; Collier Cameron, A.; Hussain, G. A. J. +2 more
The variation of the specific intensity across the stellar disc is an essential input parameter in surface brightness reconstruction techniques such as Doppler imaging, where the relative intensity contributions of different surface elements are important in detecting star-spots. We use PHOENIX and ATLAS model atmospheres to model light curves der…
Deviations from passive evolution - star formation and the ultraviolet excess in z~ 1 radio galaxies
Inskip, K. J.; Best, P. N.; Longair, M. S.
Galaxy colours are determined for two samples of 6C and 3CR radio sources at z~ 1, differing by a factor of ~6 in radio power. Corrections are made for emission-line contamination and the presence of any nuclear point source, and the data analysed as a function of both redshift and the radio source properties. The galaxy colours are remarkably sim…
Morphological classification of nearby galaxies based on asymmetry and luminosity concentration
Doi, M.; Shimasaku, K.; Okamura, S. +2 more
We investigate the behaviour of the asymmetry parameter A as a morphological parameter using a `volume-limited' sample of 349 galaxies (distance <=25Mpc,MV<=-18.5mag) and a larger magnitude-limited sample of 707 nearby galaxies. We confirm the correlation of A with morphological type. The late-type galaxies (Sdm, Sm and Im) have l…
The possible detection of high-redshift Type II QSOs in deep fields
Meiksin, Avery
The colours of high-redshift Type II quasi-stellar objects (QSOs) are synthesized from observations of moderate-redshift systems. It is shown that Type II QSOs are comparable to starbursts at matching the colours of z850-dropouts and i775-drops in the Hubble UltraDeep Field, and more naturally account for the bluest objects d…