|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'506'133
Articles rated: 2609
26 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
The Radio Sky at Meter Wavelengths: m-Mode Analysis Imaging with the Owens Valley Long Wavelength Array | | Michael W. Eastwood
; Marin M. Anderson
; Ryan M. Monroe
; Gregg Hallinan
; Benjamin R. Barsdell
; Stephen A. Bourke
; M. A. Clark
; Steven W. Ellingson
; Jayce Dowell
; Hugh Garsden
; Lincoln J. Greenhill
; Jacob M. Hartman
; Jonathon Kocz
; T. Joseph W. Lazio
; Danny C. Price
; Frank K. Schinzel
; Gregory B. Taylor
; Harish K. Vedantham
; Yuankun Wang
; David P. Woody
; | | Date: |
26 Oct 2017 | | Abstract: | A host of new low-frequency radio telescopes seek to measure the 21-cm
transition of neutral hydrogen from the early universe. These telescopes have
the potential to directly probe star and galaxy formation at redshifts $20
gtrsim z gtrsim 7$, but are limited by the dynamic range they can achieve
against foreground sources of low-frequency radio emission. Consequently, there
is a growing demand for modern, high-fidelity maps of the sky at frequencies
below 200 MHz for use in foreground modeling and removal. We describe a new
widefield imaging technique for drift-scanning interferometers,
Tikhonov-regularized $m$-mode analysis imaging. This technique constructs
images of the entire sky in a single synthesis imaging step with exact
treatment of widefield effects. We describe how the CLEAN algorithm can be
adapted to deconvolve maps generated by $m$-mode analysis imaging. We
demonstrate Tikhonov-regularized $m$-mode analysis imaging using the Owens
Valley Long Wavelength Array (OVRO-LWA) by generating 8 new maps of the sky
north of $delta=-30^circ$ with 15 arcmin angular resolution, at frequencies
evenly spaced between 36.528 MHz and 73.152 MHz, and $sim$800 mJy/beam thermal
noise. These maps are a 10-fold improvement in angular resolution over existing
full-sky maps at comparable frequencies, which have angular resolutions $ge
2^circ$. Each map is constructed exclusively from interferometric observations
and does not represent the globally averaged sky brightness. Future
improvements will incorporate total power radiometry, improved thermal noise,
and improved angular resolution -- due to the planned expansion of the OVRO-LWA
to 2.6 km baselines. These maps serve as a first step on the path to the use of
more sophisticated foreground filters in 21-cm cosmology incorporating the
measured angular and frequency structure of all foreground contaminants. | | Source: | arXiv, 1711.0466 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER