Murchison widefield array observations of anomalous variability

A serendipitous night-time detection of interplanetary scintillation

D. L. Kaplan, S. J. Tingay, P. K. Manoharan, J. P. Macquart, P. Hancock, J. Morgan, D. A. Mitchell, R. D. Ekers, R. B. Wayth, C. Trott, T. Murphy, D. Oberoi, I. H. Cairns, L. Feng, N. Kudryavtseva, G. Bernardi, Judd Bowman, F. Briggs, R. J. Cappallo, A. A. Deshpande & 17 others B. M. Gaensler, L. J. Greenhill, N. Hurley Walker, B. J. Hazelton, M. Johnston Hollitt, C. J. Lonsdale, S. R. McWhirter, M. F. Morales, E. Morgan, S. M. Ord, T. Prabu, N. Udaya Shankar, K. S. Srivani, R. Subrahmanyan, R. L. Webster, A. Williams, C. L. Williams

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

We present observations of high-amplitude rapid (2 s) variability toward two bright, compact extragalactic radio sources out of several hundred of the brightest radio sources in one of the 30° × 30° Murchison Widefield Array (MWA) Epoch of Reionization fields using the MWA at 155 MHz. After rejecting intrinsic, instrumental, and ionospheric origins we consider the most likely explanation for this variability to be interplanetary scintillation (IPS), likely the result of a large coronal mass ejection propagating from the Sun. This is confirmed by roughly contemporaneous observations with the Ooty Radio Telescope. We see evidence for structure on spatial scales ranging from 106 km. The serendipitous night-time nature of these detections illustrates the new regime that the MWA has opened for IPS studies with sensitive night-time, wide-field, low-frequency observations. This regime complements traditional dedicated strategies for observing IPS and can be utilized in real-time to facilitate dedicated follow-up observations. At the same time, it allows large-scale surveys for compact (arcsec) structures in low-frequency radio sources despite the 2′ resolution of the array.

Original languageEnglish (US)
Article numberL12
JournalAstrophysical Journal Letters
Volume809
Issue number1
DOIs
StatePublished - Aug 10 2015

Fingerprint

night
scintillation
radio
extragalactic radio sources
low frequencies
radio telescopes
coronal mass ejection
complement
ionospherics
time measurement
detection

Keywords

  • radio continuum: galaxies
  • scattering
  • Sun: coronal mass ejections (CMEs)
  • Sun: heliosphere
  • techniques: interferometric

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Kaplan, D. L., Tingay, S. J., Manoharan, P. K., Macquart, J. P., Hancock, P., Morgan, J., ... Williams, C. L. (2015). Murchison widefield array observations of anomalous variability: A serendipitous night-time detection of interplanetary scintillation. Astrophysical Journal Letters, 809(1), [L12]. https://doi.org/10.1088/2041-8205/809/1/L12

Murchison widefield array observations of anomalous variability : A serendipitous night-time detection of interplanetary scintillation. / Kaplan, D. L.; Tingay, S. J.; Manoharan, P. K.; Macquart, J. P.; Hancock, P.; Morgan, J.; Mitchell, D. A.; Ekers, R. D.; Wayth, R. B.; Trott, C.; Murphy, T.; Oberoi, D.; Cairns, I. H.; Feng, L.; Kudryavtseva, N.; Bernardi, G.; Bowman, Judd; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Gaensler, B. M.; Greenhill, L. J.; Hurley Walker, N.; Hazelton, B. J.; Johnston Hollitt, M.; Lonsdale, C. J.; McWhirter, S. R.; Morales, M. F.; Morgan, E.; Ord, S. M.; Prabu, T.; Udaya Shankar, N.; Srivani, K. S.; Subrahmanyan, R.; Webster, R. L.; Williams, A.; Williams, C. L.

In: Astrophysical Journal Letters, Vol. 809, No. 1, L12, 10.08.2015.

Research output: Contribution to journalArticle

Kaplan, DL, Tingay, SJ, Manoharan, PK, Macquart, JP, Hancock, P, Morgan, J, Mitchell, DA, Ekers, RD, Wayth, RB, Trott, C, Murphy, T, Oberoi, D, Cairns, IH, Feng, L, Kudryavtseva, N, Bernardi, G, Bowman, J, Briggs, F, Cappallo, RJ, Deshpande, AA, Gaensler, BM, Greenhill, LJ, Hurley Walker, N, Hazelton, BJ, Johnston Hollitt, M, Lonsdale, CJ, McWhirter, SR, Morales, MF, Morgan, E, Ord, SM, Prabu, T, Udaya Shankar, N, Srivani, KS, Subrahmanyan, R, Webster, RL, Williams, A & Williams, CL 2015, 'Murchison widefield array observations of anomalous variability: A serendipitous night-time detection of interplanetary scintillation', Astrophysical Journal Letters, vol. 809, no. 1, L12. https://doi.org/10.1088/2041-8205/809/1/L12
Kaplan, D. L. ; Tingay, S. J. ; Manoharan, P. K. ; Macquart, J. P. ; Hancock, P. ; Morgan, J. ; Mitchell, D. A. ; Ekers, R. D. ; Wayth, R. B. ; Trott, C. ; Murphy, T. ; Oberoi, D. ; Cairns, I. H. ; Feng, L. ; Kudryavtseva, N. ; Bernardi, G. ; Bowman, Judd ; Briggs, F. ; Cappallo, R. J. ; Deshpande, A. A. ; Gaensler, B. M. ; Greenhill, L. J. ; Hurley Walker, N. ; Hazelton, B. J. ; Johnston Hollitt, M. ; Lonsdale, C. J. ; McWhirter, S. R. ; Morales, M. F. ; Morgan, E. ; Ord, S. M. ; Prabu, T. ; Udaya Shankar, N. ; Srivani, K. S. ; Subrahmanyan, R. ; Webster, R. L. ; Williams, A. ; Williams, C. L. / Murchison widefield array observations of anomalous variability : A serendipitous night-time detection of interplanetary scintillation. In: Astrophysical Journal Letters. 2015 ; Vol. 809, No. 1.
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abstract = "We present observations of high-amplitude rapid (2 s) variability toward two bright, compact extragalactic radio sources out of several hundred of the brightest radio sources in one of the 30° × 30° Murchison Widefield Array (MWA) Epoch of Reionization fields using the MWA at 155 MHz. After rejecting intrinsic, instrumental, and ionospheric origins we consider the most likely explanation for this variability to be interplanetary scintillation (IPS), likely the result of a large coronal mass ejection propagating from the Sun. This is confirmed by roughly contemporaneous observations with the Ooty Radio Telescope. We see evidence for structure on spatial scales ranging from 106 km. The serendipitous night-time nature of these detections illustrates the new regime that the MWA has opened for IPS studies with sensitive night-time, wide-field, low-frequency observations. This regime complements traditional dedicated strategies for observing IPS and can be utilized in real-time to facilitate dedicated follow-up observations. At the same time, it allows large-scale surveys for compact (arcsec) structures in low-frequency radio sources despite the 2′ resolution of the array.",
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T2 - A serendipitous night-time detection of interplanetary scintillation

AU - Kaplan, D. L.

AU - Tingay, S. J.

AU - Manoharan, P. K.

AU - Macquart, J. P.

AU - Hancock, P.

AU - Morgan, J.

AU - Mitchell, D. A.

AU - Ekers, R. D.

AU - Wayth, R. B.

AU - Trott, C.

AU - Murphy, T.

AU - Oberoi, D.

AU - Cairns, I. H.

AU - Feng, L.

AU - Kudryavtseva, N.

AU - Bernardi, G.

AU - Bowman, Judd

AU - Briggs, F.

AU - Cappallo, R. J.

AU - Deshpande, A. A.

AU - Gaensler, B. M.

AU - Greenhill, L. J.

AU - Hurley Walker, N.

AU - Hazelton, B. J.

AU - Johnston Hollitt, M.

AU - Lonsdale, C. J.

AU - McWhirter, S. R.

AU - Morales, M. F.

AU - Morgan, E.

AU - Ord, S. M.

AU - Prabu, T.

AU - Udaya Shankar, N.

AU - Srivani, K. S.

AU - Subrahmanyan, R.

AU - Webster, R. L.

AU - Williams, A.

AU - Williams, C. L.

PY - 2015/8/10

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N2 - We present observations of high-amplitude rapid (2 s) variability toward two bright, compact extragalactic radio sources out of several hundred of the brightest radio sources in one of the 30° × 30° Murchison Widefield Array (MWA) Epoch of Reionization fields using the MWA at 155 MHz. After rejecting intrinsic, instrumental, and ionospheric origins we consider the most likely explanation for this variability to be interplanetary scintillation (IPS), likely the result of a large coronal mass ejection propagating from the Sun. This is confirmed by roughly contemporaneous observations with the Ooty Radio Telescope. We see evidence for structure on spatial scales ranging from 106 km. The serendipitous night-time nature of these detections illustrates the new regime that the MWA has opened for IPS studies with sensitive night-time, wide-field, low-frequency observations. This regime complements traditional dedicated strategies for observing IPS and can be utilized in real-time to facilitate dedicated follow-up observations. At the same time, it allows large-scale surveys for compact (arcsec) structures in low-frequency radio sources despite the 2′ resolution of the array.

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KW - scattering

KW - Sun: coronal mass ejections (CMEs)

KW - Sun: heliosphere

KW - techniques: interferometric

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