Time-domain and spectral properties of pulsars at 154 MHz

We present 154 MHz Murchison Widefield Array imaging observations and variability information for a sample of pulsars. Over the declination range −80° < δ < 10°, we detect 17 known pulsars with mean flux density greater than 0.3 Jy. We explore the variability properties of this sample on time-...

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Bibliographic Details
Main Authors: Bell, M., Murphy, T., Johnston, S., Kaplan, D., Croft, S., Hancock, P., Callingham, J., Zic, A., Dobie, D., Swiggum, J., Rowlinson, A., Hurley-Walker, N., Offringa, A., Bernardi, G., Bowman, J., Briggs, F., Cappallo, R., Deshpande, A., Gaensler, B., Greenhill, L., Hazelton, B., Johnston-Hollitt, M., Lonsdale, C., McWhirter, S., Mitchell, D., Morales, M., Morgan, E., Oberoi, D., Ord, S., Prabu, T., Udaya Shankar, N., Srivani, K., Subrahmanyan, R., Tingay, Steven, Wayth, Randall, Webster, R., Williams, A., Williams, C.
Format: Journal Article
Published: Oxford University Press 2016
Online Access:http://hdl.handle.net/20.500.11937/16193
Description
Summary:We present 154 MHz Murchison Widefield Array imaging observations and variability information for a sample of pulsars. Over the declination range −80° < δ < 10°, we detect 17 known pulsars with mean flux density greater than 0.3 Jy. We explore the variability properties of this sample on time-scales of minutes to years. For three of these pulsars, PSR J0953+0755, PSR J0437−4715, and PSR J0630−2834, we observe interstellar scintillation and variability on time-scales of greater than 2 min. One further pulsar, PSR J0034−0721, showed significant variability, the physical origins of which are difficult to determine. The dynamic spectra for PSR J0953+0755 and PSR J0437−4715 show discrete time and frequency structure consistent with diffractive interstellar scintillation and we present the scintillation bandwidth and time-scales from these observations. The remaining pulsars within our sample were statistically non-variable. We also explore the spectral properties of this sample and find spectral curvature in pulsars PSR J0835−4510, PSR J1752−2806, and PSR J0437−4715.