Low-frequency imaging of fields at high galactic latitude with the murchison widefield Array 32 element prototype

Christopher L. Williams; Jacqueline N. Hewitt; Alan M. Levine; Angelica De Oliveira-Costa; Judd Bowman; Frank H. Briggs; B. M. Gaensler; Lars L. Hernquist; Daniel A. Mitchell; Miguel F. Morales; Shiv K. Sethi; Ravi Subrahmanyan; Elaine M. Sadler; Wayne Arcus; David G. Barnes; Gianni Bernardi; John D. Bunton; Roger C. Cappallo; Brian W. Crosse; Brian E. Corey; Avinash Deshpande; Ludi Desouza; David Emrich; Robert F. Goeke; Lincoln J. Greenhill; Bryna J. Hazelton; David Herne; David L. Kaplan; Justin C. Kasper; Barton B. Kincaid; Ronald Koenig; Eric Kratzenberg; Colin J. Lonsdale; Mervyn J. Lynch; S. Russell McWhirter; Edward H. Morgan; Divya Oberoi; Stephen M. Ord; Joseph Pathikulangara; Thiagaraj Prabu; Ronald A. Remillard; Alan E E Rogers; D. Anish Roshi; Joseph E. Salah; Robert J. Sault; N. Udaya Shankar; K. S. Srivani; Jamie B. Stevens; Steven J. Tingay; Randall B. Wayth; Mark Waterson; Rachel L. Webster; Alan R. Whitney; Andrew J. Williams; J. Stuart B Wyithe

doi:10.1088/0004-637X/755/1/47

Low-frequency imaging of fields at high galactic latitude with the murchison widefield Array 32 element prototype

Christopher L. Williams, Jacqueline N. Hewitt, Alan M. Levine, Angelica De Oliveira-Costa, Judd Bowman, Frank H. Briggs, B. M. Gaensler, Lars L. Hernquist, Daniel A. Mitchell, Miguel F. Morales, Shiv K. Sethi, Ravi Subrahmanyan, Elaine M. Sadler, Wayne Arcus, David G. Barnes, Gianni Bernardi, John D. Bunton, Roger C. Cappallo, Brian W. Crosse, Brian E. CoreyAvinash Deshpande, Ludi Desouza, David Emrich, Robert F. Goeke, Lincoln J. Greenhill, Bryna J. Hazelton, David Herne, David L. Kaplan, Justin C. Kasper, Barton B. Kincaid, Ronald Koenig, Eric Kratzenberg, Colin J. Lonsdale, Mervyn J. Lynch, S. Russell McWhirter, Edward H. Morgan, Divya Oberoi, Stephen M. Ord, Joseph Pathikulangara, Thiagaraj Prabu, Ronald A. Remillard, Alan E E Rogers, D. Anish Roshi, Joseph E. Salah, Robert J. Sault, N. Udaya Shankar, K. S. Srivani, Jamie B. Stevens, Steven J. Tingay, Randall B. Wayth, Mark Waterson, Rachel L. Webster, Alan R. Whitney, Andrew J. Williams, J. Stuart B Wyithe

CLAS-NS: Earth and Space Exploration, School of (SESE)

Research output: Contribution to journal › Article › peer-review

25 Scopus citations

Abstract

The Murchison Widefield Array (MWA) is a new low-frequency, wide-field-of-view radio interferometer under development at the Murchison Radio-astronomy Observatory in Western Australia. We have used a 32 element MWA prototype interferometer (MWA-32T) to observe two 50° diameter fields in the southern sky, covering a total of 2700 deg², in order to evaluate the performance of the MWA-32T, to develop techniques for epoch of reionization experiments, and to make measurements of astronomical foregrounds. We developed a calibration and imaging pipeline for the MWA-32T, and used it to produce 15′ angular resolution maps of the two fields in the 110-200MHz band. We perform a blind source extraction using these confusion-limited images, and detect 655 sources at high significance with an additional 871 lower significance source candidates. We compare these sources with existing low-frequency radio surveys in order to assess the MWA-32T system performance, wide-field analysis algorithms, and catalog quality. Our source catalog is found to agree well with existing low-frequency surveys in these regions of the sky and with statistical distributions of point sources derived from Northern Hemisphere surveys; it represents one of the deepest surveys to date of this sky field in the 110-200MHz band.

Original language	English (US)
Article number	47
Journal	Astrophysical Journal
Volume	755
Issue number	1
DOIs	https://doi.org/10.1088/0004-637X/755/1/47
State	Published - Aug 10 2012

Keywords

dark ages
first stars
instrumentation: interferometers
methods: data analysis
reionization
surveys

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1088/0004-637X/755/1/47

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Williams, C. L., Hewitt, J. N., Levine, A. M., De Oliveira-Costa, A., Bowman, J., Briggs, F. H., Gaensler, B. M., Hernquist, L. L., Mitchell, D. A., Morales, M. F., Sethi, S. K., Subrahmanyan, R., Sadler, E. M., Arcus, W., Barnes, D. G., Bernardi, G., Bunton, J. D., Cappallo, R. C., Crosse, B. W., ... Wyithe, J. S. B. (2012). Low-frequency imaging of fields at high galactic latitude with the murchison widefield Array 32 element prototype. Astrophysical Journal, 755(1), [47]. https://doi.org/10.1088/0004-637X/755/1/47

Low-frequency imaging of fields at high galactic latitude with the murchison widefield Array 32 element prototype. / Williams, Christopher L.; Hewitt, Jacqueline N.; Levine, Alan M.; De Oliveira-Costa, Angelica; Bowman, Judd; Briggs, Frank H.; Gaensler, B. M.; Hernquist, Lars L.; Mitchell, Daniel A.; Morales, Miguel F.; Sethi, Shiv K.; Subrahmanyan, Ravi; Sadler, Elaine M.; Arcus, Wayne; Barnes, David G.; Bernardi, Gianni; Bunton, John D.; Cappallo, Roger C.; Crosse, Brian W.; Corey, Brian E.; Deshpande, Avinash; Desouza, Ludi; Emrich, David; Goeke, Robert F.; Greenhill, Lincoln J.; Hazelton, Bryna J.; Herne, David; Kaplan, David L.; Kasper, Justin C.; Kincaid, Barton B.; Koenig, Ronald; Kratzenberg, Eric; Lonsdale, Colin J.; Lynch, Mervyn J.; McWhirter, S. Russell; Morgan, Edward H.; Oberoi, Divya; Ord, Stephen M.; Pathikulangara, Joseph; Prabu, Thiagaraj; Remillard, Ronald A.; Rogers, Alan E E; Roshi, D. Anish; Salah, Joseph E.; Sault, Robert J.; Shankar, N. Udaya; Srivani, K. S.; Stevens, Jamie B.; Tingay, Steven J.; Wayth, Randall B.; Waterson, Mark; Webster, Rachel L.; Whitney, Alan R.; Williams, Andrew J.; Wyithe, J. Stuart B.

In: Astrophysical Journal, Vol. 755, No. 1, 47, 10.08.2012.

Research output: Contribution to journal › Article › peer-review

Williams, CL, Hewitt, JN, Levine, AM, De Oliveira-Costa, A, Bowman, J, Briggs, FH, Gaensler, BM, Hernquist, LL, Mitchell, DA, Morales, MF, Sethi, SK, Subrahmanyan, R, Sadler, EM, Arcus, W, Barnes, DG, Bernardi, G, Bunton, JD, Cappallo, RC, Crosse, BW, Corey, BE, Deshpande, A, Desouza, L, Emrich, D, Goeke, RF, Greenhill, LJ, Hazelton, BJ, Herne, D, Kaplan, DL, Kasper, JC, Kincaid, BB, Koenig, R, Kratzenberg, E, Lonsdale, CJ, Lynch, MJ, McWhirter, SR, Morgan, EH, Oberoi, D, Ord, SM, Pathikulangara, J, Prabu, T, Remillard, RA, Rogers, AEE, Roshi, DA, Salah, JE, Sault, RJ, Shankar, NU, Srivani, KS, Stevens, JB, Tingay, SJ, Wayth, RB, Waterson, M, Webster, RL, Whitney, AR, Williams, AJ & Wyithe, JSB 2012, 'Low-frequency imaging of fields at high galactic latitude with the murchison widefield Array 32 element prototype', Astrophysical Journal, vol. 755, no. 1, 47. https://doi.org/10.1088/0004-637X/755/1/47

Williams, Christopher L. ; Hewitt, Jacqueline N. ; Levine, Alan M. ; De Oliveira-Costa, Angelica ; Bowman, Judd ; Briggs, Frank H. ; Gaensler, B. M. ; Hernquist, Lars L. ; Mitchell, Daniel A. ; Morales, Miguel F. ; Sethi, Shiv K. ; Subrahmanyan, Ravi ; Sadler, Elaine M. ; Arcus, Wayne ; Barnes, David G. ; Bernardi, Gianni ; Bunton, John D. ; Cappallo, Roger C. ; Crosse, Brian W. ; Corey, Brian E. ; Deshpande, Avinash ; Desouza, Ludi ; Emrich, David ; Goeke, Robert F. ; Greenhill, Lincoln J. ; Hazelton, Bryna J. ; Herne, David ; Kaplan, David L. ; Kasper, Justin C. ; Kincaid, Barton B. ; Koenig, Ronald ; Kratzenberg, Eric ; Lonsdale, Colin J. ; Lynch, Mervyn J. ; McWhirter, S. Russell ; Morgan, Edward H. ; Oberoi, Divya ; Ord, Stephen M. ; Pathikulangara, Joseph ; Prabu, Thiagaraj ; Remillard, Ronald A. ; Rogers, Alan E E ; Roshi, D. Anish ; Salah, Joseph E. ; Sault, Robert J. ; Shankar, N. Udaya ; Srivani, K. S. ; Stevens, Jamie B. ; Tingay, Steven J. ; Wayth, Randall B. ; Waterson, Mark ; Webster, Rachel L. ; Whitney, Alan R. ; Williams, Andrew J. ; Wyithe, J. Stuart B. / Low-frequency imaging of fields at high galactic latitude with the murchison widefield Array 32 element prototype. In: Astrophysical Journal. 2012 ; Vol. 755, No. 1.

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title = "Low-frequency imaging of fields at high galactic latitude with the murchison widefield Array 32 element prototype",

abstract = "The Murchison Widefield Array (MWA) is a new low-frequency, wide-field-of-view radio interferometer under development at the Murchison Radio-astronomy Observatory in Western Australia. We have used a 32 element MWA prototype interferometer (MWA-32T) to observe two 50° diameter fields in the southern sky, covering a total of 2700 deg2, in order to evaluate the performance of the MWA-32T, to develop techniques for epoch of reionization experiments, and to make measurements of astronomical foregrounds. We developed a calibration and imaging pipeline for the MWA-32T, and used it to produce 15′ angular resolution maps of the two fields in the 110-200MHz band. We perform a blind source extraction using these confusion-limited images, and detect 655 sources at high significance with an additional 871 lower significance source candidates. We compare these sources with existing low-frequency radio surveys in order to assess the MWA-32T system performance, wide-field analysis algorithms, and catalog quality. Our source catalog is found to agree well with existing low-frequency surveys in these regions of the sky and with statistical distributions of point sources derived from Northern Hemisphere surveys; it represents one of the deepest surveys to date of this sky field in the 110-200MHz band.",

keywords = "dark ages, first stars, instrumentation: interferometers, methods: data analysis, reionization, surveys",

author = "Williams, {Christopher L.} and Hewitt, {Jacqueline N.} and Levine, {Alan M.} and {De Oliveira-Costa}, Angelica and Judd Bowman and Briggs, {Frank H.} and Gaensler, {B. M.} and Hernquist, {Lars L.} and Mitchell, {Daniel A.} and Morales, {Miguel F.} and Sethi, {Shiv K.} and Ravi Subrahmanyan and Sadler, {Elaine M.} and Wayne Arcus and Barnes, {David G.} and Gianni Bernardi and Bunton, {John D.} and Cappallo, {Roger C.} and Crosse, {Brian W.} and Corey, {Brian E.} and Avinash Deshpande and Ludi Desouza and David Emrich and Goeke, {Robert F.} and Greenhill, {Lincoln J.} and Hazelton, {Bryna J.} and David Herne and Kaplan, {David L.} and Kasper, {Justin C.} and Kincaid, {Barton B.} and Ronald Koenig and Eric Kratzenberg and Lonsdale, {Colin J.} and Lynch, {Mervyn J.} and McWhirter, {S. Russell} and Morgan, {Edward H.} and Divya Oberoi and Ord, {Stephen M.} and Joseph Pathikulangara and Thiagaraj Prabu and Remillard, {Ronald A.} and Rogers, {Alan E E} and Roshi, {D. Anish} and Salah, {Joseph E.} and Sault, {Robert J.} and Shankar, {N. Udaya} and Srivani, {K. S.} and Stevens, {Jamie B.} and Tingay, {Steven J.} and Wayth, {Randall B.} and Mark Waterson and Webster, {Rachel L.} and Whitney, {Alan R.} and Williams, {Andrew J.} and Wyithe, {J. Stuart B}",

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AU - Williams, Christopher L.

AU - Hewitt, Jacqueline N.

AU - Levine, Alan M.

AU - De Oliveira-Costa, Angelica

AU - Bowman, Judd

AU - Briggs, Frank H.

AU - Gaensler, B. M.

AU - Hernquist, Lars L.

AU - Mitchell, Daniel A.

AU - Morales, Miguel F.

AU - Sethi, Shiv K.

AU - Subrahmanyan, Ravi

AU - Sadler, Elaine M.

AU - Arcus, Wayne

AU - Barnes, David G.

AU - Bernardi, Gianni

AU - Bunton, John D.

AU - Cappallo, Roger C.

AU - Crosse, Brian W.

AU - Corey, Brian E.

AU - Deshpande, Avinash

AU - Desouza, Ludi

AU - Emrich, David

AU - Goeke, Robert F.

AU - Greenhill, Lincoln J.

AU - Hazelton, Bryna J.

AU - Herne, David

AU - Kaplan, David L.

AU - Kasper, Justin C.

AU - Kincaid, Barton B.

AU - Koenig, Ronald

AU - Kratzenberg, Eric

AU - Lonsdale, Colin J.

AU - Lynch, Mervyn J.

AU - McWhirter, S. Russell

AU - Morgan, Edward H.

AU - Oberoi, Divya

AU - Ord, Stephen M.

AU - Pathikulangara, Joseph

AU - Prabu, Thiagaraj

AU - Remillard, Ronald A.

AU - Rogers, Alan E E

AU - Roshi, D. Anish

AU - Salah, Joseph E.

AU - Sault, Robert J.

AU - Shankar, N. Udaya

AU - Srivani, K. S.

AU - Stevens, Jamie B.

AU - Tingay, Steven J.

AU - Wayth, Randall B.

AU - Waterson, Mark

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AU - Whitney, Alan R.

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AB - The Murchison Widefield Array (MWA) is a new low-frequency, wide-field-of-view radio interferometer under development at the Murchison Radio-astronomy Observatory in Western Australia. We have used a 32 element MWA prototype interferometer (MWA-32T) to observe two 50° diameter fields in the southern sky, covering a total of 2700 deg2, in order to evaluate the performance of the MWA-32T, to develop techniques for epoch of reionization experiments, and to make measurements of astronomical foregrounds. We developed a calibration and imaging pipeline for the MWA-32T, and used it to produce 15′ angular resolution maps of the two fields in the 110-200MHz band. We perform a blind source extraction using these confusion-limited images, and detect 655 sources at high significance with an additional 871 lower significance source candidates. We compare these sources with existing low-frequency radio surveys in order to assess the MWA-32T system performance, wide-field analysis algorithms, and catalog quality. Our source catalog is found to agree well with existing low-frequency surveys in these regions of the sky and with statistical distributions of point sources derived from Northern Hemisphere surveys; it represents one of the deepest surveys to date of this sky field in the 110-200MHz band.

KW - dark ages

KW - first stars

KW - instrumentation: interferometers

KW - methods: data analysis

KW - reionization

KW - surveys

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Low-frequency imaging of fields at high galactic latitude with the murchison widefield Array 32 element prototype

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