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Product Name
OVRO-LWA Radio Maps
Coord. System
Galactic
Projection Type
HEALPix, ring, res 11 (Nside=2048)
Resolution
15 to 25 arcmin

Description

The Owens Valley Radio Observatory Long Wavelength Array (OVRO-LWA) sky maps cover the sky north of -30 degrees declination at eight frequencies from 36.528 to 73.152 MHz at 15 to 25 arcminute angular resolution (a function of frequency and declination). The thermal noise in each map is roughly 800 mJy/beam. The eight brightest northern hemisphere point sources have been removed from each map (Cyg A, Cas A, Vir A, Tau A, Her A, Hya A, 3C 123, and 3C 353), and a 2 degree radius region at the location of the Sun during the observation period is blanked (centered at l=+45.7 degrees, b=-47.9 degrees). Cyg A was used as a flux calibrator for this work, but the overall error on the flux scale is between 5 and 10%. At the lowest frequencies, ionospheric effects generate ~10% artifacts within 1 degree of bright point sources. The OVRO-LWA sky maps are generated using Tikhonov-regularized m-mode analysis imaging.


       ν    ∆ν         FWHM (major axis × minor axis)       Noise
#    MHz   MHz       δ = 0◦      δ = +45◦     δ = +75◦    K    mJy/beam
====================================================================
1  36.528  0.024  26.0 × 19.1  20.2 × 16.9  19.8 × 18.7  595.  799.
2  41.760  0.024  23.3 × 17.5  18.5 × 16.0  18.3 × 17.4  541.  824.
3  46.992  0.024  20.9 × 16.3  17.4 × 15.2  17.6 × 16.9  417.  717.
4  52.224  0.024  18.7 × 15.2  16.2 × 15.0  16.0 × 15.8  418.  814.
5  57.456  0.024  18.0 × 14.9  15.9 × 15.0  15.7 × 15.4  354.  819.
6  62.688  0.024  17.8 × 15.0  15.8 × 14.9  15.7 × 15.4  309.  843.
7  67.920  0.024  17.6 × 15.0  15.9 × 14.7  15.8 × 15.6  281.  894.
8  73.152  0.024  18.6 × 15.1  16.8 × 14.6  16.6 × 16.1  154.  598.
 

More details can be found in:

"The Radio Sky at Meter Wavelengths: m-Mode Analysis Imaging with the Owens Valley Long Wavelength Array",
Eastwood, M.W., et al. 2017, AJ, submitted, arXiv

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