Discovery of a steep-spectrum low-luminosity pulsar with the Murchison Widefield Array
N. A. Swainston, N. D. R. Bhat, M. Sokolowski, S. J. McSweeney, S. Kudale, S. Dai, K. R. Smith, I. S. Morrison, R. M. Shannon, W. van Straten, M. Xue, S. M. Ord… 展开作者
N. A. Swainston, N. D. R. Bhat, M. Sokolowski, S. J. McSweeney, S. Kudale, S. Dai, K. R. Smith, I. S. Morrison, R. M. Shannon, W. van Straten, M. Xue, S. M. Ord, S. E. Tremblay, B. W. Meyers, A. Williams, G. Sleap, M. Johnston-Hollitt, D. L. Kaplan, S. J. Tingay, R. B. Wayth
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12 pages, 6 figures, 2 tables, Accepted for publication in The ApJ Letters
We report the discovery of the first new pulsar with the Murchison Widefield Array (MWA), PSR J0036$-$1033, a long-period (0.9 s) nonrecycled pulsar with a dispersion measure (DM) of 23.1 ${\rm pc\,cm^{-3}}$. It was found after processing only a small fraction ($\sim$1%) of data from an ongoing all-sky pulsar survey. Follow-up observations have been made with the MWA, the upgraded Giant Metrewave Radio Telescope (uGMRT), and the Parkes 64 m telescopes, spanning a frequency range from $\sim$150 MHz to 4 GHz. The pulsar is faint, with an estimated flux density ($S$) of $\sim$1 mJy at 400 MHz and a spectrum $S(ν)\,\propto\,ν^{-2.0 \pm 0.2}$, where $ν$ is frequency. The DM-derived distance implies that it is also a low-luminosity source ($\sim$ 0.1 ${\rm mJy\,kpc^2}$ at 1400 MHz). The analysis of archival MWA observations reveals that the pulsar's mean flux density varies by up to a factor of $\sim$5-6 on timescales of several weeks to months. By combining MWA and uGMRT data, the pulsar position was determined to arcsecond precision. We also report on polarization properties detected in the MWA and Parkes bands. The pulsar's nondetection in previous pulsar and continuum imaging surveys, the observed high variability, and its detection in a small fraction of the survey data searched to date, all hint at a larger population of pulsars that await discovery in the southern hemisphere, with the MWA and the future low-frequency Square Kilometre Array.
Simultaneous Observations of Giant Pulses from the Crab Pulsar, with the Murchison Widefield Array and Parkes Radio Telescope: Implications for the Giant Pulse Emission Mechanism
Discovery of a 24-millisecond pulsar in a very long orbit with the Murchison Widefield Array
International Centre for Radio Astronomy Research, Curtin University（国际射电天文研究中心，科廷大学）；Australian SKA Regional Centre (AusSRC), Curtin University（澳大利亚SKA区域中心（AusSRC），科廷大学）；Max-Planck-Institut for Radioastronomy（马克斯·普朗克射电天文研究所）
Murchison Widefield Array Observations of Anomalous Variability: A Serendipitous Night-time Detection of Interplanetary Scintillation
我们目前的观测高振幅快速（2秒）的变化对两个明亮的，紧凑的河外射电源的几百个最明亮的无线电源中的一个30x30度MWA时代的再电离场使用默奇森宽场阵列（MWA）在155 MHz。在拒绝内在的，仪器，电离层的起源，我们认为最有可能的解释，这种变化是行星际闪烁（IPS），可能是一个大的日冕物质抛射从太阳传播的结果。这一点可以通过Ooty射电望远镜大致同期的观测得到证实。我们看到了从1e6公里的空间尺度上的结构的证据<1000 km to >。这些探测的偶然夜间性质说明了MWA为IPS研究开放的新机制，具有灵敏的夜间，宽场，低频观测。这一制度补充了传统的专门观测入侵防御系统的战略，并可实时用于促进专门的后续观测。与此同时，尽管阵列的分辨率为2弧分，但它允许对低频射电源中的紧凑（弧秒）结构进行大规模调查。
Candidate radio supernova remnants observed by the GLEAM survey over $345^\circ < l < 60^\circ$ and $180^\circ < l < 240^\circ$
我们研究了银河系和河外全天空默奇森宽场阵列（GLEAM）调查的最新数据，包括$345^\circ < l < 60^\circ$，$180^\circ < l < 240^\circ$，使用这些数据和宽场红外巡天探测器的数据来跟踪其他来源的候选超新星遗迹。在该地区提出的101个候选地区中，我们能够明确确认10个为SNRs，暂时确认2个为SNRs，并将5个重新分类为Hii地区。另外两个在我们的图像中可以检测到，但很难分类;剩下的82个在这些数据中无法检测到。我们还调查了18个未分类的多阵列银河平面成像巡天（MAGPIS）候选SNR，新确认了三个SNR，将两个重新分类为Hii区域，并探索了另外两个不寻常的光谱和形态。
