S-band Polarization All Sky Survey (S-PASS): survey description and maps. (arXiv:1903.09420v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Carretti_E/0/1/0/all/0/1">E. Carretti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Haverkorn_M/0/1/0/all/0/1">M. Haverkorn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Staveley_Smith_L/0/1/0/all/0/1">L. Staveley-Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernardi_G/0/1/0/all/0/1">G. Bernardi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gaensler_B/0/1/0/all/0/1">B.M. Gaensler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kesteven_M/0/1/0/all/0/1">M.J. Kesteven</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poppi_S/0/1/0/all/0/1">S. Poppi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brown_S/0/1/0/all/0/1">S. Brown</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crocker_R/0/1/0/all/0/1">R.M. Crocker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Purcell_C/0/1/0/all/0/1">C. Purcell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schnitzler_D/0/1/0/all/0/1">D.H.F.M. Schnitzler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sun_X/0/1/0/all/0/1">X. Sun</a>
We present the S-Band Polarization All Sky Survey (S-PASS), a survey of
polarized radio emission over the southern sky at Dec~$< -1^circ$ taken with
the Parkes radio telescope at 2.3~GHz. The main aim was to observe at a
frequency high enough to avoid strong depolarization at intermediate Galactic
latitudes (still present at 1.4 GHz) to study Galactic magnetism, but low
enough to retain ample Signal-to-Noise ratio (S/N) at high latitudes for
extragalactic and cosmological science. We developed a new scanning strategy
based on long azimuth scans, and a corresponding map-making procedure to make
recovery of the overall mean signal of Stokes $Q$ and $U$ possible, a
long-standing problem with polarization observations. We describe the scanning
strategy, map-making procedure, and validation tests. The overall mean signal
is recovered with a precision better than 0.5%. The maps have a mean
sensitivity of 0.81 mK on beam--size scales and show clear polarized signals,
typically to within a few degrees of the Galactic plane, with ample S/N
everywhere (the typical signal in low emission regions is 13 mK, and 98.6% of
the pixels have S/N $> 3$). The largest depolarization areas are in the inner
Galaxy, associated with the Sagittarius Arm. We have also computed a Rotation
Measure map combining S-PASS with archival data from the WMAP and Planck
experiments. A Stokes $I$ map has been generated, with a sensitivity limited to
the confusion level of 9 mK.
We present the S-Band Polarization All Sky Survey (S-PASS), a survey of
polarized radio emission over the southern sky at Dec~$< -1^circ$ taken with
the Parkes radio telescope at 2.3~GHz. The main aim was to observe at a
frequency high enough to avoid strong depolarization at intermediate Galactic
latitudes (still present at 1.4 GHz) to study Galactic magnetism, but low
enough to retain ample Signal-to-Noise ratio (S/N) at high latitudes for
extragalactic and cosmological science. We developed a new scanning strategy
based on long azimuth scans, and a corresponding map-making procedure to make
recovery of the overall mean signal of Stokes $Q$ and $U$ possible, a
long-standing problem with polarization observations. We describe the scanning
strategy, map-making procedure, and validation tests. The overall mean signal
is recovered with a precision better than 0.5%. The maps have a mean
sensitivity of 0.81 mK on beam–size scales and show clear polarized signals,
typically to within a few degrees of the Galactic plane, with ample S/N
everywhere (the typical signal in low emission regions is 13 mK, and 98.6% of
the pixels have S/N $> 3$). The largest depolarization areas are in the inner
Galaxy, associated with the Sagittarius Arm. We have also computed a Rotation
Measure map combining S-PASS with archival data from the WMAP and Planck
experiments. A Stokes $I$ map has been generated, with a sensitivity limited to
the confusion level of 9 mK.
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