J/A+A/694/A169 STAPS images (Sun+, 2025)
The Southern Twenty-centimeter All-sky Polarization Survey (STAPS):
Survey description and maps.
Sun X., Haverkorn M., Carretti E., Landecker T., Gaensler B.M., Poppi S.,
Staveley-Smith L., Gao X., Han J.
<Astron. Astrophys. 694, A169 (2025)>
=2025A&A...694A.169S 2025A&A...694A.169S (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Magnetic fields ; Polarization
Keywords: polarization - techniques: polarimetric - surveys -
ISM: magnetic field - ISM: structure
Abstract:
We present data processing and verification of the Southern
Twenty-centimetre All-sky Polarization Survey (STAPS) conducted with
Murriyang, the Parkes 64-m telescope. The survey covers the sky area
of -89°<Dec<0° and the frequency range of 1.3-1.8GHz split
into 1-MHz channels. STAPS was observed commensally with the S-band
Polarization All-Sky Survey (S-PASS). The survey is composed of long
azimuth scans, which allows us to absolutely calibrate Stokes Q and U
with the data processing procedure developed for S-PASS. We obtained
I, Q, and U maps on both the flux density scale (Jy/beam) and the main
beam brightness temperature scale (K), for the 301 frequency channels
with sufficiently good data. The temperature scale is tied to the
Global Magneto-ionic Medium Survey (GMIMS) high-band north sky survey
conducted with the Dominion Radio Astrophysical Observatory 26-m
telescope. All the STAPS maps are smoothed to a common resolution of
20'. The root mean square (rms) noise per channel ranges from about
16mK to 8mK for I, and from about 8mK to 5mK for Q and U, at
frequencies from 1.3 to 1.8GHz. The rms noise in Q and U varies with
declination and reaches minimum at declination of -89°. We also
ran rotation measure (RM) synthesis and RM clean to obtain peak
polarized intensity and Faraday depth maps. The whole STAPS data
processing was validated by comparing flux densities of compact
sources, pixel flux density versus pixel flux density for Cen A, pixel
temperature versus pixel temperature for the entire survey area, and
the RMs of extragalactic sources between STAPS and other measurements.
The uncertainty of the flux density scale is less than 10%. STAPS
delivers an L-band (λ20cm) multifrequency polarization view of
the Galaxy, and will help advance our understanding of the Galactic
magnetic field and magnetized interstellar medium.
Description:
The image cubes are in unit of main beam brightness temperature K, and
the resolution is 20 arcmin.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
freq.dat 12 301 List of frequencies corresponding to each frame
in the cubes
list.dat 109 3 List of fits maps
fits/* . 3 Individual fits maps
--------------------------------------------------------------------------------
Byte-by-byte Description of file: freq.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.1 Hz Freq Frequency
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 32 I3 --- Nz Number of pixels along Z-axis
34- 41 I8 Kibyte size Size of FITS file
43- 65 A23 --- FileName Name of FITS file, in subdirectory fits
67-109 A43 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Xiaohui Sun, xhsun(at)ynu.edu.cn
(End) Patricia Vannier [CDS] 23-Jan-2025