Search Publications
Testing the photoionization models of powerful radio galaxies: mixed line-emitting media in 3C 321
Tadhunter, C. N.; Axon, D. J.; Robinson, A. +1 more
The photoionization models for the narrow emission-line regions of powerful radio galaxies have yet to be tested in depth. To this end, we present high-quality long-slit spectroscopy of the powerful double-nucleus radio galaxy 3C 321. The data have good enough spatial resolution to be able to trace the variation in emission-line properties on kpc …
The optical spectrum of the planetary nebula NGC 6543
Feibelman, W. A.; de Koter, A.; Hyung, S. +2 more
With the Hamilton echelle spectrograph at the Lick Observatory, emission-rich spectral lines of the planetary nebula NGC 6543 were secured in the wavelength range from 3550 to 10100Å. We chose two bright regions, ~8arcsec east and ~13arcsec north of the central star, the physical conditions and chemical abundances of which may differ as a result o…
Low-mass spectroscopic binaries in the Hyades: a candidate brown dwarf companion
Reid, I. Neill; Mahoney, S.
We have used the HIRES echelle spectrograph on the Keck I telescope to obtain high-resolution spectroscopy of 51 late-type M dwarfs in the Hyades cluster. Cross-correlating the calibrated data against spectra of white dwarfs allows us to determine heliocentric velocities with an accuracy of +/-0.3kms-1. 27 stars were observed at two epo…
OB association members in the ACT and TRC catalogues
Hoogerwerf, Ronnie
The Hipparcos Catalogue contains members of nearby OB associations brighter than 12th magnitude in V. However, membership lists are complete only to magnitude V=7.3. In this paper we discuss whether proper motions listed in the `Astrographic Catalogue+Tycho' reference catalogue (ACT) and the Tycho Reference Catalogue (TRC), which are complete to V…
A 500kms-1 outflow from the young bipolar planetary nebula Mz 3
Redman, M. P.; Meaburn, J.; Holloway, A. J. +2 more
We report the discovery of a pair of hypersonic (~=+/-500kms-1) velocity features located along the bipolar axis of the young planetary nebula Mz 3. The possible physical mechanisms that can produce such extreme outflows are briefly discussed and compared with mechanisms thought to operate in MyCn 18, He 2-111 and KjPn 8, all of which e…
Young massive star clusters in M51
Larsen, Søren S.
A search for young massive star clusters (YMCs) in the nearby face-on spiral galaxy M51 (NGC 5194) has been carried out using UBV CCD images from the prime focus camera on the Lick 3-m Shane telescope. The YMC population is found to be quite rich with a specific U-band luminosity TL(U)~1.4, consistent with the high current star formatio…
A multiwavelength view at the heart of the superwind in NGC253
Forbes, Duncan A.; Brodie, Jean P.; Stevens, Ian R. +2 more
Although NGC253 is one of the nearest starburst galaxies, the activity in its central regions is yet to be fully understood. Here we present new optical data from the Hubble Space Telescope of its central region, which reveal numerous discrete sources in a ring-like structure. This is combined with data at infrared, millimetre, radio and X-ray wav…
HST ultraviolet observations of rapid variability in the accretion-disc wind of BZ Cam
Ringwald, F. A.; Prinja, Raman K.; Knigge, Christian +1 more
We present results from time-resolved Hubble Space Telescope (HST) GHRS ultraviolet spectroscopy of the nova-like cataclysmic variable BZ Cam. Extensive changes are recorded in the extended absorption troughs of the UV resonance line profiles, which betray a highly unsteady and continuously variable supersonic outflow. The large-scale line-profile…
Highly polarized structures in the near-nuclear regions of Cygnus A: intrinsic anisotropy within the cones?
Tadhunter, C. N.; Packham, C.; Sparks, W. +6 more
We present near-infrared imaging polarimetry observations of the nucleus of Cygnus A (z= 0.0567), taken with the NICMOS camera of the Hubble Space Telescope (HST) at a wavelength of 2.0µm. These maps reveal a highly collimated region of polarized emission straddling the nucleus and extending to a radius of 1.2arcsec. Remarkably, this feature…
Imaging of the protoelliptical NGC 1700 and its globular cluster system
Forbes, Duncan A.; Brodie, Jean P.; Kissler-Patig, Markus +1 more
An excellent candidate for a young elliptical, or `protoelliptical' galaxy is NGC 1700. Here we present new B-, V- and I-band imaging using the Keck telescope, and reanalyse existing V- and I-band images from the Hubble Space Telescope. After subtracting a model of the galaxy from the Keck images, NGC 1700 reveals two symmetric tidal tail-like str…