Cyclic spectroscopy of The Millisecond Pulsar, B1937+21

Abstract

Cyclic spectroscopy is a signal processing technique that was originally developed for engineering applications and has recently been introduced into the field of pulsar astronomy. It is a powerful technique with many attractive features, not least of which is the explicit rendering of information about the relative phases in any filtering imposed on the signal, thus making holography a more straightforward proposition. Here we present methods for determining optimum estimates of both the filter itself and the statistics of the unfiltered signal, starting from a measured cyclic spectrum. In the context of radio pulsars these quantities tell us the impulse response of the interstellar medium and the intrinsic pulse profile. We demonstrate our techniques by application to 428 MHz Arecibo data on the millisecond pulsar B1937+21, obtaining the pulse profile free from the effects of interstellar scattering. As expected, the intrinsic profile exhibits main- and inter-pulse components that are narrower than they appear in the scattered profile; it also manifests some weak, but sharp features that are revealed for the first time at low frequency. We determine the structure of the received electric-field envelope as a function of delay and Doppler-shift. Our delay-Doppler image has a high dynamic-range and displays some pronounced, low-level power concentrations at large delays. These concentrations imply strong clumpiness in the ionized interstellar medium, on AU size-scales, which must adversely affect the timing of B1937+21.

20 pages, 9 figures, ApJ (accepted)

References in corpus (9)

• The ATNF Pulsar Catalogue
• PSRCHIVE and PSRFITS An Open Approach to Radio Pulsar Data Storage and Analysis
• DSPSR: Digital Signal Processing Software for Pulsar Astronomy
• Polarization observations of 20 millisecond pulsars
• Cyclic Spectral Analysis of Radio Pulsars
• Multi-frequency integrated profiles of pulsars
• The complex polarization angles of radio pulsars: orthogonal jumps and interstellar scattering
• High-precision geometry of a double-pole pulsar
• Interstellar Holography

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• A 24-Hour Global Campaign To Assess Precision Timing of the Millisecond Pulsar J1713+0747
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• Pulsar scintillation studies with LOFAR. I. The census
• The Thousand-Pulsar-Array programme on MeerKAT -- X. Scintillation arcs of 107 pulsars
• The NANOGrav 11-year Data Set: Pulse Profile Variability
• Millisecond Pulsar Scintillation Studies with LOFAR: Initial Results
• Variable Scintillation Arcs of Millisecond Pulsars observed with the Large European Array for Pulsars
• Interstellar Scintillation observations for PSR B0355+54
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• Pulsar Double-lensing Sheds Light on the Origin of Extreme Scattering Events
• Analysis of Multi-Hour Continuous Observations of Seven Millisecond Pulsars
• A Cyclic Spectroscopy Scintillation Study of PSR B1937+21 I. Demonstration of Improved Scintillometry
• Scattering Delay Mitigation in High Accuracy Pulsar Timing: Cyclic Spectroscopy Techniques
• H-FISTA: A hierarchical algorithm for phase retrieval with application to pulsar dynamic spectra
• Interstellar Medium Mitigation Techniques in Pulsar Timing Arrays
• Using Giant Pulses to Measure the Impulse Response of the Interstellar Medium
• A direct measurement of the electron density turbulence parameter $C_1$ and implications for the emission size of the magnetar XTE J1810-197
• Noise Budget and Interstellar Medium Mitigation Advances in the NANOGrav Pulsar Timing Array
• Pulsar Cyclic Spectroscopy in the Partial-Deconvolution Regime: Benefits & Limitations
• Improving DM estimates using low-frequency scattering-broadening estimates
• Constraining Scattering Medium Geometry with Cyclic Spectroscopy
• Interstellar Interferometry: Precise Curvature Measurement from Pulsar Secondary Spectra