Search Publications
The chromospherically active binary CFTuc revisited
Erdem, A.; Zola, S.; Doǧru, D. +1 more
This paper presents results derived from analysis of new spectroscopic and photometric observations of the chromospherically active binary system CFTuc. New high-resolution spectra, taken at the Mt. John University Observatory in 2007, were analysed using two methods: cross-correlation and Fourier-based disentangling. As a result, new radial veloc…
Exploring the spreading layer of GX 9+9 using RXTE and INTEGRAL
Hakala, P.; Paizis, A.; Vilhu, O. +3 more
We have fitted ~200 RXTE and INTEGRAL spectra of the neutron star (NS) low-mass X-ray binary (LMXB) GX 9+9 from 2002 to 2007 with a model consisting of a disc blackbody and another blackbody representing the spreading layer (SL), i.e. an extended accretion zone on the NS surface as opposed to the more traditional disc-like boundary layer. Contrary…
The magnetic field and geometry of the oblique shock in the jet of 3C 346
Birkinshaw, M.; Worrall, D. M.; Padgett, C. A. +2 more
We investigate the brightest regions of the kpc-scale jet in the powerful radio galaxy 3C 346, using new optical Hubble Space Telescope (HST) ACS/F606W polarimetry together with Chandra X-ray data and 14.9 and 22.5 GHz Very Large Array (VLA) radio polarimetry. The jet shows a close correspondence between optical and radio morphology, while the X-r…
Effects of dust abundance on the far-infrared colours of blue compact dwarf galaxies
Hirashita, Hiroyuki; Ichikawa, Tomohiro T.
We investigate the far-infrared (FIR) properties of a sample of blue compact dwarf galaxies (BCDs) observed by AKARI. By utilizing the data at wavelengths of λ = 65, 90 and 140 µm, we find that the FIR colours of the BCDs are located at the natural high-temperature extension of those of the Milky Way and the Magellanic Clouds. This implies t…
The extended ionized gas around the z = 2.44 radio galaxy MRC 0406-244: the nature of the superbubbles and the optical line brightness asymmetries
Humphrey, A.; Iwamuro, F.; Villar-Martín, M. +2 more
In this Letter, we investigate the nature of the dramatic `superbubble' emission structures associated with the z = 2.44 radio galaxy MRC 0406-244, using rest-frame optical spectroscopy and an archival Hubble Space Telescope (HST) Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) image. Based on the optical line ratios and the HST morpho…
Absolute parameters of young stars - I. U Ophiuci
Demircan, O.; Budding, E.; Inlek, G.
We have carried out an investigation of the early-type multiple star U Oph. We have used new high-resolution spectroscopy with the High Efficiency and Resolution Canterbury University Large Echelle Spectrograph (HERCULES) and 1-m McLellan Telescope of the University of Canterbury at Mt John University Observatory and literature-sourced optical and…
A lensing view on the Fundamental Plane
Leier, Dominik
For lensing galaxies, we introduce a formal velocity dispersion σlens, based on enclosed mass and the virial theorem. This is calculated from an ensemble of pixelated lens models, and found to be fairly model-independent. A sample of 18 well-known early-type lensing galaxies and two clusters is found to be consistent with σlens
A second black hole candidate in a M31 globular cluster is identified with XMM-Newton
Kolb, U.; Barnard, R.
We use arguments developed in previous work to identify a second black hole candidate associated with an M31 globular cluster (GC), Bo 144, on the basis of X-ray spectral and timing properties. The 2002 XMM-Newton observation of the associated X-ray source (hereafter XBo 144) revealed behaviour that is common to all low-mass X-ray binaries (LMXBs)…
Globular cluster candidates in NGC 891
Rejkuba, M.; Mouhcine, M.; Ibata, R. +1 more
We use deep images taken with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope of the disc galaxy NGC 891 to search for globular cluster (GC) candidates. This galaxy has long been considered to be a close analogue in size and structure to the Milky Way and is nearly edge-on, facilitating studies of its halo population. The…
The disc-dominated host galaxy of FR-I radio source B2 0722+30
Morganti, R.; Tadhunter, C. N.; Holt, J. +4 more
We present new observational results that conclude that the nearby radio galaxy B2 0722+30 is one of the very few known disc galaxies in the low-redshift Universe that host a classical double-lobed radio source. In this paper, we use HI observations, deep optical imaging, stellar population synthesis modelling and emission-line diagnostics to stud…