Abstract
Original language | English |
---|---|
Pages (from-to) | 16pp |
Journal | Astrophysical Journal |
Volume | 771 |
DOIs | |
Publication status | Published - 2013 |
Fingerprint
Cite this
}
A 189 MHz, 2400 deg2 polarization survey with the murchison widefield array 32-element prototype. / Bernardi, G.; Greenhill, L.J.; Mitchell, D.A.; Ord, S.M.; Hazelton, B.J.; Gaensler, B.M.; De Oliveira-Costa, A.; Morales, M.F.; Shankar, N.U.; Subrahmanyan, R.; Wayth, R.B.; Lenc, E.; Williams, C.L.; Arcus, W.; Arora, B.S.; Barnes, D.G.; Bowman, J.D.; Briggs, F.H.; Bunton, J.D.; Cappallo, R.J.; Corey, B.E.; Deshpande, A.; Desouza, L.; Emrich, D.; Goeke, R.; Herne, D.; Hewitt, J.N.; Johnston-Hollitt, M.; Kaplan, D.; Kasper, J.C.; Kincaid, B.B.; Koenig, R.; Kratzenberg, E.; Lonsdale, C.J.; Lynch, M.J.; Mcwhirter, S.R.; Morgan, E.; Oberoi, D.; Pathikulangara, J.; Prabu, T.; Remillard, R.A.; Rogers, A.E.E.; Roshi, A.; Salah, J.E.; Sault, R.J.; Srivani, K.S.; Stevens, J.; Tingay, S.J.; Waterson, M.; Webster, R.L.; Whitney, A.R.; Williams, Andrew; Wyithe, J.S.B.
In: Astrophysical Journal, Vol. 771, 2013, p. 16pp.Research output: Contribution to journal › Article
TY - JOUR
T1 - A 189 MHz, 2400 deg2 polarization survey with the murchison widefield array 32-element prototype
AU - Bernardi, G.
AU - Greenhill, L.J.
AU - Mitchell, D.A.
AU - Ord, S.M.
AU - Hazelton, B.J.
AU - Gaensler, B.M.
AU - De Oliveira-Costa, A.
AU - Morales, M.F.
AU - Shankar, N.U.
AU - Subrahmanyan, R.
AU - Wayth, R.B.
AU - Lenc, E.
AU - Williams, C.L.
AU - Arcus, W.
AU - Arora, B.S.
AU - Barnes, D.G.
AU - Bowman, J.D.
AU - Briggs, F.H.
AU - Bunton, J.D.
AU - Cappallo, R.J.
AU - Corey, B.E.
AU - Deshpande, A.
AU - Desouza, L.
AU - Emrich, D.
AU - Goeke, R.
AU - Herne, D.
AU - Hewitt, J.N.
AU - Johnston-Hollitt, M.
AU - Kaplan, D.
AU - Kasper, J.C.
AU - Kincaid, B.B.
AU - Koenig, R.
AU - Kratzenberg, E.
AU - Lonsdale, C.J.
AU - Lynch, M.J.
AU - Mcwhirter, S.R.
AU - Morgan, E.
AU - Oberoi, D.
AU - Pathikulangara, J.
AU - Prabu, T.
AU - Remillard, R.A.
AU - Rogers, A.E.E.
AU - Roshi, A.
AU - Salah, J.E.
AU - Sault, R.J.
AU - Srivani, K.S.
AU - Stevens, J.
AU - Tingay, S.J.
AU - Waterson, M.
AU - Webster, R.L.
AU - Whitney, A.R.
AU - Williams, Andrew
AU - Wyithe, J.S.B.
PY - 2013
Y1 - 2013
N2 - We present a Stokes I, Q and U survey at 189 MHz with the Murchison Widefield Array 32 element prototype covering 2400 deg2. The survey has a 15.6 arcmin angular resolution and achieves a noise level of 15 mJy beam-1. We demonstrate a novel interferometric data analysis that involves calibration of drift scan data, integration through the co-addition of warped snapshot images, and deconvolution of the point-spread function through forward modeling. We present a point source catalog down to a flux limit of 4 Jy. We detect polarization from only one of the sources, PMN J0351-2744, at a level of 1.8% ± 0.4%, whereas the remaining sources have a polarization fraction below 2%. Compared to a reported average value of 7% at 1.4 GHz, the polarization fraction of compact sources significantly decreases at low frequencies. We find a wealth of diffuse polarized emission across a large area of the survey with a maximum peak of 13 K, primarily with positive rotation measure values smaller than +10 rad m-2. The small values observed indicate that the emission is likely to have a local origin (closer than a few hundred parsecs). There is a large sky area at α ≥ 2h30 m where the diffuse polarized emission rms is fainter than 1 K. Within this area of low Galactic polarization we characterize the foreground properties in a cold sky patch at (α, δ) = (4h, -27.°6) in terms of three-dimensional power spectra. © 2013. The American Astronomical Society. All rights reserved.
AB - We present a Stokes I, Q and U survey at 189 MHz with the Murchison Widefield Array 32 element prototype covering 2400 deg2. The survey has a 15.6 arcmin angular resolution and achieves a noise level of 15 mJy beam-1. We demonstrate a novel interferometric data analysis that involves calibration of drift scan data, integration through the co-addition of warped snapshot images, and deconvolution of the point-spread function through forward modeling. We present a point source catalog down to a flux limit of 4 Jy. We detect polarization from only one of the sources, PMN J0351-2744, at a level of 1.8% ± 0.4%, whereas the remaining sources have a polarization fraction below 2%. Compared to a reported average value of 7% at 1.4 GHz, the polarization fraction of compact sources significantly decreases at low frequencies. We find a wealth of diffuse polarized emission across a large area of the survey with a maximum peak of 13 K, primarily with positive rotation measure values smaller than +10 rad m-2. The small values observed indicate that the emission is likely to have a local origin (closer than a few hundred parsecs). There is a large sky area at α ≥ 2h30 m where the diffuse polarized emission rms is fainter than 1 K. Within this area of low Galactic polarization we characterize the foreground properties in a cold sky patch at (α, δ) = (4h, -27.°6) in terms of three-dimensional power spectra. © 2013. The American Astronomical Society. All rights reserved.
U2 - 10.1088/0004-637X/771/2/105
DO - 10.1088/0004-637X/771/2/105
M3 - Article
VL - 771
SP - 16pp
JO - The Astrophysical Journal
JF - The Astrophysical Journal
SN - 0004-637X
ER -