Search Publications
The diverse nature of optical emission lines in brightest cluster galaxies: IFU observations of the central kiloparsec
Robert, Carmelle; McGee, Sean L.; Edwards, Louise O. V. +1 more
We present integral field spectroscopy of the nebular line emission in a sample of nine brightest cluster galaxies (BCGs). The sample was chosen to probe both cooling flow and non-cooling flow clusters, as well as a range of cluster X-ray luminosities. The line emission morphology and velocity gradients suggest a great diversity in the properties …
A multiwavelength infrared study of NGC 891
Madden, S. C.; Galliano, F.; Bendo, G. J. +2 more
We present a multiwavlength infrared (IR) study of the nearby, edge-on, spiral galaxy NGC 891. We have examined 20 independent, spatially resolved IR images of this galaxy, 14 of which are newly reduced and/or previously unpublished images. These images span a wavelength regime from λ1.2µm in which the emission is dominated by cool stars, th…
On the origin of the 511-keV emission in the Galactic Centre
Maccarone, Thomas J.; Taylor, James E.; Silk, Joseph +1 more
Diffuse 511-keV line emission, from the annihilation of cold positrons, has been observed in the direction of the Galactic Centre for more than 30yr. The latest high-resolution maps of this emission produced by the SPI instrument on INTEGRAL suggest at least one component of the emission is spatially coincident with the distribution of ~70 luminou…
New Magellan Inamori Kyocera Echelle Observations of z < 1.5 sub-damped Lyman α systems
York, Donald G.; Kulkarni, Varsha P.; Lauroesch, James T. +3 more
The damped Lyman α (DLA) and sub-damped Lyman α (sub-DLA) systems seen in the spectra of quasi-stellar objects (QSOs) offer a unique way to study the interstellar medium (ISM) of high-redshift galaxies. In this paper, we report on new abundance determinations in a sample of 10 new systems, nine of the lesser studied sub-DLAs and one DLA along the …
The ultraluminous X-ray source population of NGC 4485/4490
Roberts, Timothy P.; Gladstone, Jeanette C.
We report the results of spectral and temporal variability studies of the ultraluminous X-ray sources (ULXs) contained within the interacting pair of galaxies NGC 4485/4490, combining Chandra and XMM-Newton observations. Each of the four separate observations provide at least modest quality spectra and light curves for each of the six previously i…
The dynamics of the giant radio galaxy 3C457
Hardcastle, M. J.; Croston, J. H.; Saikia, D. J. +1 more
We present multifrequency radio observations with the Giant Metrewave Radio Telescope and Very Large Array, and X-ray observations with the X-ray Multi-Mirror Mission (XMM-Newton) telescope of the giant radio source (GRS) 3C457. We have detected the core, lobes and the environment of the GRS in X-ray. We examine the relationships between the radio…
On the sizes of neutral hydrogen regions giving rise to damped Lyα absorption systems
Rao, S.; Turnshek, D. A.; Monier, E. M.
Using quasi-stellar object (QSO) absorption-line spectra obtained along closely spaced sightlines, we examine the transverse sizes of regions containing large columns of neutral hydrogen gas at redshifts z ~ 1.5. The observations are primarily of intervening damped Lyα (DLA) and sub-DLA absorption-line systems in gravitationally lensed QSOs. In pa…
Low-ionization pairs of knots in planetary nebulae: physical properties and excitation
Corradi, R. L. M.; Gonçalves, D. R.; Mampaso, A. +1 more
We obtained optical long-slit spectra of four planetary nebulae (PNe) with low-ionization pair of knots, namely He 1-1, IC 2149, KjPn 8 and NGC 7662.
These data allow us to derive the physical parameters and excitation of the pairs of knots, and those of higher ionization inner components of the nebulae, separately. Our results are as fo…The location and kinematics of the coronal-line emitting regions in active galactic nuclei
Done, C.; Ferland, G. J.; Mullaney, J. R. +2 more
We use the photoionization code CLOUDY to determine both the location and the kinematics of the optical forbidden, high-ionization line (hereafter, FHIL) emitting gas in the narrow line Seyfert 1 galaxy Ark 564. The results of our models are compared with the observed properties of these emission lines to produce a physical model that is used to e…
XMM-Newton and Suzaku analysis of the Fe K complex in the type 1 Seyfert galaxy Mrk 509
Maraschi, L.; Bianchi, S.; Cappi, M. +11 more
We report on partially overlapping XMM-Newton (~260 ks) and Suzaku (~100 ks) observations of the iron K band in the nearby, bright type 1 Seyfert galaxy Mrk 509. The source shows a resolved neutral Fe K line, most probably produced in the outer part of the accretion disc. Moreover, the source shows further emission bluewards of the 6.4 keV line du…