16,415 research outputs found
New radio observations of Circinus X-1
New radio observations of the radio-jet X-ray binary Circinus X-1 over nearly
an entire 16.6-day orbit are presented. The source continues to undergo radio
flaring in the phase interval 0.0 - 0.2 and appears to be brightening since
observations in the early 1990s. The radio flux density is well correlated with
simultaneous soft X-ray monitoring from the XTE ASM, including a secondary
flare event around phases 0.6 --0.8 observed at both energies.Comment: 5 pages, 2 figures. To appear in Proc. 4th Compton Symposium, AIP
pres
Physical Uplink Control Channel Design for 5G New Radio
The next generation wireless communication system, 5G, or New Radio (NR) will
provide access to information and sharing of data anywhere, anytime by various
users and applications with diverse multi-dimensional requirements. Physical
Uplink Control Channel (PUCCH), which is mainly utilized to convey Uplink
Control Information (UCI), is a fundamental building component to enable NR
system. Compared to Long Term Evolution (LTE), more flexible PUCCH structure is
specified in NR, aiming to support diverse applications and use cases. This
paper describes the design principles of various NR PUCCH formats and the
underlying physical structures. Further, extensive simulation results are
presented to explain the considerations behind the NR PUCCH design.Comment: 6 pages, 11 figures, accepted in IEEE 5G World Forum 201
Prospects for weak lensing studies with new radio telescopes
I outline the prospects for performing weak lensing studies with the new
generation of radio telescopes that are coming online now and in the future. I
include a description of a proposed technique to use polarization observations
in radio weak lensing analyses which could prove extremely useful for removing
a contaminating signal from intrinsic alignments. Ultimately, the Square
Kilometre Array promises to be an exceptional instrument for performing weak
lensing studies due to the high resolution, large area surveys which it will
perform. In the nearer term, the e-MERLIN instrument in the UK offers the high
sensitivity and sub-arcsec resolution required to prove weak lensing techniques
in the radio band. I describe the SuperCLASS survey -- a recently accepted
e-MERLIN legacy programme which will perform a pioneering radio weak lensing
analysis of a supercluster of galaxies.Comment: to appear in the proceedings of the 2012 Moriond cosmology meetin
New radio halos and relics in clusters of galaxies
We present here new images of relics and halo sources in rich cluster of
galaxies and the correlation between the halo radio surface brightness versus
the cluster bolometric X-ray luminosity.Comment: 2 pages, 4 figures. To appear in the Proceedings of the International
Conference: "The Origin and Evolution of Cosmic Magnetism"; Bologna 29 August
- 2 September 2005; eds R. Beck, G. Brunetti, L. Feretti, and B. Gaensler
(Astronomische Nachrichten, 2006
Calibrating CHIME, A New Radio Interferometer to Probe Dark Energy
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a transit
interferometer currently being built at the Dominion Radio Astrophysical
Observatory (DRAO) in Penticton, BC, Canada. We will use CHIME to map neutral
hydrogen in the frequency range 400 -- 800\,MHz over half of the sky, producing
a measurement of baryon acoustic oscillations (BAO) at redshifts between 0.8 --
2.5 to probe dark energy. We have deployed a pathfinder version of CHIME that
will yield constraints on the BAO power spectrum and provide a test-bed for our
calibration scheme. I will discuss the CHIME calibration requirements and
describe instrumentation we are developing to meet these requirements
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