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-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.

[1]  P. Shawhan,et al.  SIMULTANEOUS OBSERVATIONS OF GIANT PULSES FROM PULSAR PSR B0950+08 AT 42 AND 74 MHz , 2016, 1608.01948.

[2]  K. Jeganathan,et al.  A pilot ASKAP survey of radio transient events in the region around the intermittent pulsar PSR J1107 5907 , 2015, 1512.02702.

[3]  H. Falcke,et al.  A LOFAR census of non-recycled pulsars: average profiles, dispersion measures, flux densities, and spectra , 2015, 1511.01767.

[4]  N. Razavi-Ghods,et al.  Characterization of a Low-Frequency Radio Astronomy Prototype Array in Western Australia , 2015, IEEE Transactions on Antennas and Propagation.

[5]  A. Noutsos,et al.  A LOFAR census of millisecond pulsars , 2015, 1508.02948.

[6]  T. Murphy,et al.  Quantifying ionospheric effects on time-domain astrophysics with the Murchison Widefield Array , 2015, 1508.00965.

[7]  D. Kaplan,et al.  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 , 2015, 1507.04830.

[8]  E. Lenc,et al.  BROADBAND SPECTRAL MODELING OF THE EXTREME GIGAHERTZ-PEAKED SPECTRUM RADIO SOURCE PKS B0008-421 , 2015, 1507.04819.

[9]  K. Lee,et al.  Low-frequency spectral turn-overs in millisecond pulsars studied from imaging observations , 2015, 1507.03732.

[10]  E. Lenc,et al.  GLEAM: The GaLactic and Extragalactic All-Sky MWA Survey , 2015, Publications of the Astronomical Society of Australia.

[11]  Cathryn M. Trott,et al.  Real‐time imaging of density ducts between the plasmasphere and ionosphere , 2015, 1504.06470.

[12]  Y. Levin,et al.  A study of multifrequency polarization pulse profiles of millisecond pulsars , 2015, 1503.01841.

[13]  F. Schinzel,et al.  OBSERVATIONS OF GIANT PULSES FROM PULSAR B0950+08 USING LWA1 , 2015, 1502.01282.

[14]  S. J. Tingay,et al.  The Low-Frequency Environment of the Murchison Widefield Array: Radio-Frequency Interference Analysis and Mitigation , 2015, Publications of the Astronomical Society of Australia.

[15]  Roger Cappallo,et al.  The Murchison Widefield Array Commissioning Survey: A Low-Frequency Catalogue of 14 110 Compact Radio Sources over 6 100 Square Degrees , 2014, Publications of the Astronomical Society of Australia.

[16]  Alan E. E. Rogers,et al.  THE LOW-FREQUENCY CHARACTERISTICS OF PSR J0437−4715 OBSERVED WITH THE MURCHISON WIDE-FIELD ARRAY , 2014, 1407.4745.

[17]  T. Murphy,et al.  wsclean: an implementation of a fast, generic wide-field imager for radio astronomy , 2014, 1407.1943.

[18]  S. Velzen,et al.  The Very Large Array Low-frequency Sky Survey Redux (VLSSr) , 2014, 1404.0694.

[19]  J. Swiggum,et al.  PsrPopPy: an open-source package for pulsar population simulations , 2013, 1311.3427.

[20]  D. Lorimer,et al.  The pulsar spectral index distribution , 2013, 1302.2053.

[21]  A. R. Whitney,et al.  The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies , 2012, Publications of the Astronomical Society of Australia.

[22]  A. Singal,et al.  GIANT-PULSE EMISSION FROM PSR B0950+08 , 2012, 1209.5093.

[23]  Andrew Hopkins,et al.  Compact continuum source finding for next generation radio surveys , 2012, 1202.4500.

[24]  J. Roerdink,et al.  A morphological algorithm for improving radio-frequency interference detection , 2012, 1201.3364.

[25]  M. C. Toribio,et al.  LOFAR: The LOw-Frequency ARray , 2013, 1305.3550.

[26]  M. Keith,et al.  17- and 24-GHz observations of southern pulsars , 2011, 1105.3961.

[27]  Y. Gupta,et al.  Pulsars with gigahertz-peaked spectra , 2011, 1105.2065.

[28]  A. Noutsos,et al.  Observing pulsars and fast transients with LOFAR , 2011, 1104.1577.

[29]  B. Skiff,et al.  VizieR Online Data Catalog , 2009 .

[30]  R. Schilizzi,et al.  The Square Kilometre Array , 2006, Astronomical Telescopes + Instrumentation.

[31]  Christopher L. Williams,et al.  The Murchison Widefield Array: Design Overview , 2009, Proceedings of the IEEE.

[32]  Namir E. Kassim,et al.  The Long Wavelength Array , 2009, Proceedings of the IEEE.

[33]  M. Kramer,et al.  New pulsar rotation measures and the Galactic magnetic field , 2008, 0803.0677.

[34]  T. Murphy,et al.  The second epoch Molonglo Galactic Plane Survey: compact source catalogue , 2007, 0708.3092.

[35]  M. Mclaughlin,et al.  The Parkes Multibeam Pulsar Survey - VI. Discovery and timing of 142 pulsars and a Galactic population analysis , 2006, astro-ph/0607640.

[36]  D. Lorimer,et al.  A Periodically Active Pulsar Giving Insight into Magnetospheric Physics , 2006, Science.

[37]  V. Kaspi,et al.  Birth and Evolution of Isolated Radio Pulsars , 2005, astro-ph/0512585.

[38]  R. Perley,et al.  The VLA Low-Frequency Sky Survey , 2005, 0706.1191.

[39]  D. Lorimer,et al.  Handbook of Pulsar Astronomy , 2004 .

[40]  J. Cordes,et al.  The microarcsecond sky and cosmic turbulence , 2004, astro-ph/0410109.

[41]  A. Lyne,et al.  Long-term timing observations of 374 pulsars , 2004 .

[42]  X. Wu,et al.  Long-term flux density variations of pulsars: Theoretical structure functions and comparisons with observations , 2003 .

[43]  J. Curran,et al.  SUMSS: a wide-field radio imaging survey of the southern sky – II. The source catalogue , 2003, astro-ph/0303188.

[44]  J. Cordes,et al.  A New Model for the Galactic Distribution of Free Electrons and its Fluctuations , 2002, astro-ph/0207156.

[45]  S. Johnston,et al.  High Time Resolution Observations of the Vela Pulsar , 2001, astro-ph/0101146.

[46]  M. Kramer,et al.  Pulsar spectra of radio emission , 2000, astro-ph/0010233.

[47]  D. Stinebring,et al.  Five Years of Pulsar Flux Density Monitoring: Refractive Scintillation and the Interstellar Medium , 2000 .

[48]  V. Malofeev,et al.  Flux densities of 235 pulsars at 102.5 MHz , 2000 .

[49]  N. Bhat,et al.  Long-Term Scintillation Studies of Pulsars. II. Refractive Effects and the Spectrum of Plasma Density Fluctuations , 1998, astro-ph/9810362.

[50]  D. Kaplan,et al.  Pulsars in the NRAO VLA Sky Survey , 1998 .

[51]  N. Bhat,et al.  Long-Term Scintillation Studies of Pulsars. I. Observations and Basic Results , 1998, astro-ph/9810354.

[52]  L. Nicastro,et al.  Scintillation parameters for 49 pulsars , 1998 .

[53]  J. Goodman.  Radio scintillation of gamma-ray-burst afterglows , 1997, astro-ph/9706084.

[54]  G. W. Torrence,et al.  The Texas Survey of Radio Sources Covering -35.5 degrees < declination < 71.5 degrees at 365 MHz , 1996 .

[55]  M. Bailes,et al.  Observations of the millisecond pulsar J0437-4715 at 76 MHz , 1996 .

[56]  John W. Armstrong,et al.  Electron Density Power Spectrum in the Local Interstellar Medium , 1995 .

[57]  D. Lorimer,et al.  Multifrequency flux density measurements of 280 pulsars , 1995 .

[58]  O. Slee,et al.  Radio sources observed with the Culgoora circular array , 1995 .

[59]  E. Greisen,et al.  The NRAO VLA Sky Survey , 1996 .

[60]  R. N. Manchester,et al.  Catalog of 558 pulsars , 1993 .

[61]  D. Lorimer,et al.  Discovery of a very bright, nearby binary millisecond pulsar , 1993, Nature.

[62]  B. Rickett,et al.  Refractive Interstellar Scintillation of Pulsar Intensities at 74 MHz , 1993 .

[63]  Electron density fluctuations in the local interstellar bubble , 1992, Nature.

[64]  Ramesh Narayan,et al.  The physics of pulsar scintillation , 1992, Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences.

[65]  J. Biggs.  An Analysis of Radio Pulsar Nulling Statistics , 1992 .

[66]  D. Stinebring,et al.  Long-Term Pulsar Flux Monitoring and Refractive Interstellar Scintillation: 3 Years of Results , 1992 .

[67]  D. Stinebring,et al.  Pulsar flux stability and refractive interstellar scintillation , 1990 .

[68]  J. Cordes.  Space velocities of radio pulsars from interstellar scintillations , 1986 .

[69]  J. Cordes,et al.  Null Transition Times, Quantized Drift Modes, and No Memory across Nulls for PSR 1944+17 , 1986 .

[70]  S. Kulkarni,et al.  A millisecond pulsar , 1982, Nature.

[71]  J. Taylor,et al.  The second Molonglo pulsar survey – discovery of 155 pulsars , 1978 .

[72]  B. Rickett,et al.  Interstellar Scattering and Scintillation of Radio Waves , 1977 .

[73]  J. Taylor,et al.  The Radio Emission from Pulsar MP 0031-07 , 1970 .

[74]  H. K. Hesse,et al.  Long Term Variations of Pulsar Intensities , 1970, Nature.

[75]  A. Vaughan,et al.  Highly Dispersed Pulsar and Three Others , 1969, Nature.

[76]  A. Hewish,et al.  Observations of some further Pulsed Radio Sources , 1968, Nature.