Galactic synchrotron emissivity measurements between 250° &lt;<i>l</i>&lt; 355° from the GLEAM survey with the MWA

Su, H.; Hurley‐Walker, N.; Jackson, C. A.; McClure-Griffiths, N. M.; Tingay, S. J.; Hindson, L.; Hancock, P. J.; Wayth, R. B.; Gaensler, B. M.; Morgan, John S.; Johnston‐Hollitt, M.; Lenc, E.; Bell, M. E.; Callingham, J. R.; Dwarkanath, K. S.; For, Bi-Qing; Kapińska, A. D.; McKinley, B.; Offringa, A. R.; Procopio, P.; Wu, Chen; Zheng, Qian

doi:10.1093/mnras/stw2959

Cited by 19 publications

(28 citation statements)

References 44 publications

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“…In a 30.9-MHz Galactic plane survey, conducted by Kassim (1988) with the Clark Lake Teepee-Tee Telescope, S 74 appears as a negative absorption hole against the Galactic background (we refer the reader to Nord et al 2006 andSu et al 2017a,b for other similar cases). There is evidence for such behaviour at 74 MHz as well (J. Miller-Jones, priv.…”

Section: The H II Region S 74mentioning

confidence: 99%

LOFAR 150-MHz observations of SS 433 and W 50

Broderick

Fender

Miller-Jones

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present LOFAR high-band data over the frequency range 115-189 MHz for the X-ray binary SS 433, obtained in an observing campaign from 2013 February -2014 May. Our results include a deep, wide-field map, allowing a detailed view of the surrounding supernova remnant W 50 at low radio frequencies, as well as a light curve for SS 433 determined from shorter monitoring runs. The complex morphology of W 50 is in excellent agreement with previously published higher-frequency maps; we find additional evidence for a spectral turnover in the eastern wing, potentially due to foreground free-free absorption. Furthermore, SS 433 is tentatively variable at 150 MHz, with both a debiased modulation index of 11 per cent and a χ 2 probability of a flat light curve of 8.2 × 10 −3 . By comparing the LOFAR flux densities with contemporaneous observations carried out at 4800 MHz with the RATAN-600 telescope, we suggest that an observed ∼0.5-1 Jy rise in the 150-MHz flux density may correspond to sustained flaring activity over a period of approximately six months at 4800 MHz. However, the increase is too large to be explained with a standard synchrotron bubble model. We also detect a wealth of structure along the nearby Galactic plane, including the most complete detection to date of the radio shell of the candidate supernova remnant G 38.7−1.4. This further demonstrates the potential of supernova remnant studies with the current generation of low-frequency radio telescopes.

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Section: The H II Region S 74mentioning

confidence: 99%

LOFAR 150-MHz observations of SS 433 and W 50

Broderick

Fender

Miller-Jones

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…Phase I of the MWA was successfully used by Hindson et al (2016) to detect and measure 306 H i i regions. Su et al (2017Su et al ( , 2018) went on to use the distinct spectral signature of these regions to perform cosmic ray tomography of the Galactic Plane. Foreground measurements, between the H i i region and Earth, are more difficult, as an absolute measurement of the emissivity must be calculated, which is impossi-ble for an interferometer which does not measure total power.…”

Section: Cosmic Ray Tomographymentioning

confidence: 99%

Science with the Murchison Widefield Array: Phase I results and Phase II opportunities

Beardsley

Johnston‐Hollitt

Trott

et al. 2019

Publ. Astron. Soc. Aust.

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The Murchison Widefield Array (MWA) is an open access telescope dedicated to studying the low frequency (80-300 MHz) southern sky. Since beginning operations in mid 2013, the MWA has opened a new observational window in the southern hemisphere enabling many science areas. The driving science objectives of the original design were to observe 21 cm radiation from the Epoch of Reionisation (EoR), explore the radio time domain, perform Galactic and extragalactic surveys, and monitor solar, heliospheric, and ionospheric phenomena. All together 60+ programs recorded 20,000 hours producing 146 papers to date. In 2016 the telescope underwent a major upgrade resulting in alternating compact and extended configurations. Other upgrades, including digital back-ends and a rapid-response triggering system, have been developed since the original array was commissioned. In this paper we review the major results from the prior operation of the MWA, and then discuss the new science paths enabled by the improved capabilities. We group these science opportunities by the four original science themes, but also include ideas for directions outside these categories.

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“…9 shows the GLEAM view of the Galactic centre, with strong free-free absorption and an intriguing loop of absorption perpendicular to the Galactic plane (Anderson et al, in prep). Some studies have already been published using these data: Su et al (2017) and Su et al (2018) (Davis, 1967), a previously-unknown peaked-spectrum source, the planetary nebula NGC 6369 (Curtis, 1918), and the pulsar J1820-0427 (Vaughan et al, 1969). server 4 and SkyView 5 .…”

Section: Galactic Planementioning

confidence: 99%

GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey II: Galactic plane 345° <l< 67°, 180° <l< 240°

Hurley‐Walker

Hancock

Franzen

et al. 2019

Publ. Astron. Soc. Aust.

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This work makes available a further 2,860 deg 2 of the GLEAM survey, covering half of the accessible Galactic Plane, across twenty frequency bands sampling 72-231 MHz, with resolution 4'-2'. Unlike previous GLEAM data releases, we used multi-scale c l e a n to better deconvolve large-scale Galactic structure. For the Galactic longitude ranges 345 • < l < 67 • , 180 • < l < 240 • , we provide a compact source catalogue of 22,037 components selected from a 60-MHz bandwidth image centred at 200-MHz, with RMS noise ≈ 10-20 mJy beam −1 and position accuracy better than 2". The catalogue has a completeness of 50 % at ≈ 120 mJy, and a reliability of 99.86 %. It covers Galactic latitudes 1 • ≤ |b| ≤ 10 • toward the Galactic Centre and |b| ≤ 10 • for other regions, and is available from Vizier; images covering |b| ≤ 10 • for all longitudes are made available on the GLEAM VO server and SkyView.

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Galactic synchrotron emissivity measurements between 250° <l< 355° from the GLEAM survey with the MWA

Cited by 19 publications

References 44 publications

LOFAR 150-MHz observations of SS 433 and W 50

LOFAR 150-MHz observations of SS 433 and W 50

Science with the Murchison Widefield Array: Phase I results and Phase II opportunities

GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey II: Galactic plane 345° <l< 67°, 180° <l< 240°

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