Search Publications
A high-resolution study of the interstellar medium in the luminous IRAS galaxy Arp 193
Clemens, M. S.; Alexander, P.
We present high-resolution multi-element radio-linked interferometer network (MERLIN) and Very Large Array (VLA) observations of the H I absorption towards the starburst nucleus of Arp 193 (IC 883, UGC 08387), a luminous IRAS merger. We compare the distribution of atomic gas with that of radio continuum emission, high-resolution CO data and near-i…
Period-luminosity relation for M-type semiregular variables from Hipparcos parallaxes
Yeşilyaprak, C.; Aslan, Z.
We have studied the period-luminosity (P-L) relationships of oxygen-rich semiregular (SR) variables in several wavelength bands using Hipparcos parallaxes with an accuracy of better than 10 per cent. We have shown that there is a clear dependence on period of absolute magnitude in the U,B,V,R,IC,J,H,K,L,M,N, [12], [25], [60] and [100] b…
Discovery of high-amplitude X-ray variability in the Seyfert-LINER transition galaxy NGC7589
Watson, M. G.; Osborne, J. P.; Yuan, W. +3 more
We present the first result of a programme to search for large flux variations in the X-ray sources of the XMM Serendipitous Survey compared to previous ROSAT observations. An increase in X-ray flux by a factor >10 was discovered from the nucleus of the galaxy NGC7589 on a time-scale of less than 5yr. The 0.4-10keV XMM spectrum can be approxima…
A spectral analysis of the periodicity hypothesis in cratering records
Yabushita, Shin
Analysis is made of cratering records, whereby not only the crater ages, but also the sizes can be naturally taken into account. The method adopted is the periodogram analysis first discussed by Lomb. From the crater data based on Grieve's compilation, a period can be derived when a statistical weight of a crater is taken proportional to the size …
X-ray emission from a brown dwarf in the Pleiades
Briggs, K. R.; Pye, J. P.
We report on the first detection of X-ray emission from a brown dwarf in the Pleiades, the M7-type Roque 14, obtained using the EPIC detectors on XMM-Newton. This is the first X-ray detection of a brown dwarf intermediate in age between ~12 and ~320 Myr. The emission appears persistent, although we cannot rule out flare-like behaviour with a decay…
The unusual morphology of the intragroup medium in NGC 5171
Finoguenov, Alexis; Ponman, Trevor J.; Osmond, J. P. F.
We present the results of a 24-ks XMM-Newton observation of the NGC 5171 group of galaxies. NGC 5171 is unusual in that it is an X-ray bright group (LX > 1042 erg s-1), with irregular contours which are not centred on a bright galaxy. The global spectrum is adequately described by a single-temperature APEC model…
Relationship between horizontal flow velocity and cell lifetime for supergranulation from SOHO Dopplergrams
Singh, Jagdev; Paniveni, U.; Krishan, V. +1 more
A study of 50 supergranular cells obtained from Solar and Heliospheric Observatory (SOHO) Dopplergrams was undertaken in order to investigate the relationship between the lifetime (T) and the horizontal flow velocity (vh) of the cells. For this sample, we find that the two parameters are correlated with a relation vh~T1/…
The dispersion in the Cepheid period-luminosity relation and the consequences for the extragalactic distance scale
Shanks, Tom; Allen, Paul D.
Using published Hubble Space Telescope (HST) Cepheid data from 25 galaxies, we have found a correlation between the dispersion in the Cepheid period-luminosity (P-L) relation and host galaxy metallicity, which is significant at the ~3σ level in the V band. In the I band the correlation is less significant, although the tighter intrinsic dispersion…
Mid-infrared imaging and modelling of the dust shell around post-AGB star HD 187885 (IRAS 19500-1709)
Gledhill, T. M.; Clube, K. L.
We present 10- and 20-µm images of IRAS 19500-1709 taken with the mid-infrared camera, OSCIR, mounted on the Gemini North Telescope. An extended circumstellar envelope is detected, with the N-band image indicating an elongation in a north-east-south-west direction. We use a dust radiation transport code to fit the spectral energy distributio…
Multi-object near-infrared Hα spectroscopy of z~ 1 star-forming galaxies in the Hubble Deep Field North
Wolf, Christian; Hippelein, Hans; Bunker, Andrew +6 more
We present preliminary results from a programme to obtain multi-object near-infrared spectroscopy of galaxies at redshifts 0.7 < z < 1.5. We are using the instrument CIRPASS (the Cambridge Infra-Red PAnoramic Survey Spectrograph), in multi-object mode, to survey Hα in galaxies at z~ 1. We aim to address the true star formation history of the…