Publications (25)
Cosmic ray propagation and star formation history of NGC 1961
U. Lisenfeld, P. Alexander, G. G. Pooley +1
We present new radio continuum data at 4 frequencies on the supermassive, peculiar galaxy NGC 1961. These observations allow us to separate the thermal and the nonthermal radio emi…
HI and CO observations of Arp 104: a spiral-elliptical interacting pair
H. Cullen, P. Alexander, D. A. Green +1
We present data probing the spatial and kinematical distribution of both the atomic (HI) and molecular (CO) gas in NGC 5218, the late-type barred spiral galaxy in the spiral-ellipt…
The JCMT Nearby Galaxies Legacy Survey VIII. CO data and the L(CO3-2)-L(FIR) correlation in the SINGS sample
C. D. Wilson, B. E. Warren, F. P. Israel +57
The James Clerk Maxwell Telescope Nearby Galaxies Legacy Survey (NGLS) comprises an HI-selected sample of 155 galaxies spanning all morphological types with distances less than 25…
Generative pulsar timing analysis
L Lentati, P. Alexander, M. P. Hobson
A new Bayesian method for the analysis of folded pulsar timing data is presented that allows for the simultaneous evaluation of evolution in the pulse profile in either frequency o…
Multifrequency radio continuum observations of NGC 1569: Evidence for a convective wind
U. Lisenfeld, T. Wilding, G. G. Pooley +1
We present high-sensitivity radio continuum observations with the VLA and Ryle Telescope at 1.5, 4.9, 8.4 and 15.4 GHz of the dwarf irregular galaxy NGC 1569. The radio data show a…
FR II radio galaxies with z<0.3 -- I. Properties of jets, cores and hot spots
M. J. Hardcastle, P. Alexander, G. G. Pooley +1
In previous papers we have discussed high-resolution observations of a large sample of powerful radio galaxies with z<0.3. Jets are detected in up to 80 per cent of the sample, and…
Star Formation in Close Pairs Selected from the Sloan Digital Sky Survey
B. Nikolic, H. Cullen, P. Alexander
The effect of galaxy interactions on star formation has been investigated using Data Release 1 of the Sloan Digital Sky Survey (SDSS). Both the imaging and spectroscopy data produc…
The star formation history of early-type galaxies as a function of mass and environment
M. S. Clemens, A. Bressan, B. Nikolic +3
Using the third data release of the Sloan Digital Sky Survey (SDSS) we have rigorously defined a volume limited sample of early-type galaxies in the redshift range z < 0.1. We have…
On the interaction of FR-II radio sources with the intracluster medium
P. Alexander
The effect of the expansion of powerful FR-II radio sources into a cluster environment is discussed. The analysis considers both the thermal and temporal evolution of the ICM which…
The REACH radiometer for detecting the 21-cm hydrogen signal from redshift 7.5 to 28
E. de Lera Acedo, D. I. L. de Villiers, N. Razavi-Ghods +31
Observations of the 21-cm line from primordial hydrogen promise to be one of the best tools to study the early epochs of the Universe: the Dark Ages, the Cosmic Dawn, and the subse…
The jets in 3C 296
M. J. Hardcastle, P. Alexander, G. G. Pooley +1
We present observations made with the VLA at 1.5 and 8.4 GHz of the nearby FRI radio galaxy 3C296. The most recent models of FRI radio galaxies suggest that substantial deceleratio…
Further GMRT observations of the Lockman Hole at 610 MHz
T. S. Garn, D. A. Green, J. M. Riley +1
We present further observations of the Lockman Hole field, made with the Giant Metrewave Radio Telescope at 610 MHz with a resolution of 6 x 5 arcsec^2. These complement our earlie…
The long-term effect of radio sources on the ICM
J. F. Basson, P. Alexander
We have performed 3D hydrodynamical simulations of FR-II radio sources in beta-profile cooling-flow clusters. The effects of cooling of the cluster gas were incorporated into a mod…
Clusters and Large-Scale Structure: the Synchrotron Keys
L. Rudnick, P. Alexander, H. Andernach +25
For over four decades, synchrotron-radiating sources have played a series of pathfinding roles in the study of galaxy clusters and large scale structure. Such sources are uniquely…
Radio antenna design for sky-averaged 21 cm cosmology experiments: the REACH case
J. Cumner, E. De Lera Acedo, D. I. L. de Villiers +35
Following the reported detection of an absorption profile associated with the 21~cm sky-averaged signal from the Cosmic Dawn by the EDGES experiment in 2018, a number of experiment…
FRII radio galaxies with z<0.3 -- II. Beaming and unification
M. J. Hardcastle, P. Alexander, G. G. Pooley +1
In a previous paper we presented measurements of the properties of jets and cores in a large sample of FRII radio galaxies with z<0.3. Here we test, by means of Monte Carlo simulat…
The unusual distribution of molecular gas and star formation in Arp 140
H. Cullen, P. Alexander, D. A. Green +2
We investigate the atomic and molecular interstellar medium and star formation of NGC 275, the late-type spiral galaxy in Arp 140, which is interacting with NGC 274, an early-type…
Receiver design for the REACH global 21-cm signal experiment
Ian L. V. Roque, Nima Razavi-Ghods, Steven H. Carey +35
We detail the the REACH radiometric system designed to enable measurements of the 21-cm neutral hydrogen line. Included is the radiometer architecture and end-to-end system simulat…
A relativistic mixing-layer model for jets in low-luminosity radio galaxies
Y. Wang, C. R. Kaiser, R. Laing +3
We present an analytical model for jets in Fanaroff & Riley Class I (FRI) radio galaxies, in which an initially laminar, relativistic flow is surrounded by a shear layer. We apply…
The heating of the ICM by powerful radio sources
C. R. Kaiser, P. Alexander
We present a model for the compression and heating of the ICM by powerful radio galaxies and quasars. Based on a self-similar model of the dynamical evolution of FRII-type objects…
Variations in the Fundamental constants in the QSO Host J1148+5251 at z = 6.4 and the BR1202-0725 System at z = 4.7
Lindley Lentati, C. Carilli, P. Alexander +11
We use sensitive observations of three high redshift sources; [CII] fine structure and CO(2-1) rotational transitions for the z=6.4 Quasar host galaxy (QSO) J1148+5251, and [CII] a…
Giant Metrewave Radio Telescope limits on cool HI in galaxy groups
D. A. Green, M. S. Clemens, P. Alexander +2
We present Giant Metrewave Radio Telescope 21-cm HI observations towards a sample of compact radio sources behind galaxy groups, to search for cool HI. The results -- from high dyn…
A Simple Model For Mid-Infrared Emission from Normal Galaxies
B. Nikolic, P. Alexander, D. Ford
We have combined up-to-date stellar population synthesis models, a simple radiative transfer approach, and a fully comprehensive dust model with the aim of developing a simple but…
Constraints on Cosmic Ray propagation from Radio Continuum data of NGC 2146
U. Lisenfeld, P. Alexander, G. G. Pooley +1
We present high-sensitivity multi-frequency radio continuum observations of the starburst galaxy NGC~2146. We have fitted these data with a three-dimensional diffusion model. The m…
The SCUBA Local Universe Galaxy Survey I: First Measurements of the Submillimetre Luminosity and Dust Mass Functions
L. Dunne, S. A. Eales, M. G. Edmunds +3
We have used SCUBA to observe a complete sample of 104 galaxies selected at 60 microns from the IRAS BGS and we present here the 850 micron measurements. Fitting the 60,100 and 850…