Effects Of Intermittent Emission: Noise Inventory For The Scintillating Pulsar B0834+06

Title:
Effects Of Intermittent Emission: Noise Inventory For The Scintillating Pulsar B0834+06
Authors:
Gwinn, C. R.; Johnson, M. D.; Smirnova, T. V.; Stinebring, Daniel R.
Abstract:
We compare signal and noise for observations of the scintillating pulsar B0834+06, using very long baseline interferometry and a single-dish spectrometer. Comparisons between instruments and with models suggest that amplitude variations of the pulsar strongly affect the amount and distribution of self-noise. We show that noise follows a quadratic polynomial with flux density, in spectral observations. Constant coefficients, indicative of background noise, agree well with expectation; whereas second-order coefficients, indicative of self-noise, are approximate to 3 times values expected for a pulsar with constant on-pulse flux density. We show that variations in flux density during the 10 s integration accounts for the discrepancy. In the secondary spectrum, approximate to 97% of spectral power lies within the pulsar's typical scintillation bandwidth and timescale; an extended scintillation arc contains approximate to 3%. For a pulsar with constant on-pulse flux density, noise in the dynamic spectrum will appear as a uniformly distributed background in the secondary spectrum. We find that this uniform noise background contains 95% of noise in the dynamic spectrum for interferometric observations; but only 35% of noise in the dynamic spectrum for single-dish observations. Receiver and sky dominate noise for our interferometric observations, whereas self-noise dominates for single-dish. We suggest that intermittent emission by the pulsar, on timescales < 300 mu s, concentrates self-noise near the origin in the secondary spectrum, by correlating noise over the dynamic spectrum. We suggest that intermittency sets fundamental limits on pulsar astrometry or timing. Accounting of noise may provide means for detection of intermittent sources, when effects of propagation are unknown or impractical to invert.
Citation:
Gwinn, C. R., M. D. Johnson, T. V. Smirnova, and D. R. Stinebring. 2011. "Effects Of Intermittent Emission: Noise Inventory For The Scintillating Pulsar B0834+06." Astrophysical Journal 733(1): 52-52.
Publisher:
American Astronomical Society
DATE ISSUED:
2011-05
Department:
Physics and Astronomy
Type:
article
PUBLISHED VERSION:
10.1088/0004-637X/733/1/52
PERMANENT LINK:
http://hdl.handle.net/11282/310139

Full metadata record

DC FieldValue Language
dc.contributor.authorGwinn, C. R.en_US
dc.contributor.authorJohnson, M. D.en_US
dc.contributor.authorSmirnova, T. V.en_US
dc.contributor.authorStinebring, Daniel R.en_US
dc.date.accessioned2013-12-23T16:26:22Zen
dc.date.available2013-12-23T16:26:22Zen
dc.date.issued2011-05en
dc.identifier.citationGwinn, C. R., M. D. Johnson, T. V. Smirnova, and D. R. Stinebring. 2011. "Effects Of Intermittent Emission: Noise Inventory For The Scintillating Pulsar B0834+06." Astrophysical Journal 733(1): 52-52.en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.urihttp://hdl.handle.net/11282/310139en
dc.description.abstractWe compare signal and noise for observations of the scintillating pulsar B0834+06, using very long baseline interferometry and a single-dish spectrometer. Comparisons between instruments and with models suggest that amplitude variations of the pulsar strongly affect the amount and distribution of self-noise. We show that noise follows a quadratic polynomial with flux density, in spectral observations. Constant coefficients, indicative of background noise, agree well with expectation; whereas second-order coefficients, indicative of self-noise, are approximate to 3 times values expected for a pulsar with constant on-pulse flux density. We show that variations in flux density during the 10 s integration accounts for the discrepancy. In the secondary spectrum, approximate to 97% of spectral power lies within the pulsar's typical scintillation bandwidth and timescale; an extended scintillation arc contains approximate to 3%. For a pulsar with constant on-pulse flux density, noise in the dynamic spectrum will appear as a uniformly distributed background in the secondary spectrum. We find that this uniform noise background contains 95% of noise in the dynamic spectrum for interferometric observations; but only 35% of noise in the dynamic spectrum for single-dish observations. Receiver and sky dominate noise for our interferometric observations, whereas self-noise dominates for single-dish. We suggest that intermittent emission by the pulsar, on timescales < 300 mu s, concentrates self-noise near the origin in the secondary spectrum, by correlating noise over the dynamic spectrum. We suggest that intermittency sets fundamental limits on pulsar astrometry or timing. Accounting of noise may provide means for detection of intermittent sources, when effects of propagation are unknown or impractical to invert.en_US
dc.publisherAmerican Astronomical Societyen_US
dc.identifier.doi10.1088/0004-637X/733/1/52en
dc.subject.departmentPhysics and Astronomyen_US
dc.titleEffects Of Intermittent Emission: Noise Inventory For The Scintillating Pulsar B0834+06en_US
dc.typearticleen_US
dc.identifier.journalAstrophysical Journalen_US
dc.subject.keywordMethods--Data analysisen_US
dc.subject.keywordPulsars--Individual (B0834+06)en_US
dc.subject.keywordScatteringen_US
dc.subject.keywordTechniques: interferometricen_US
dc.identifier.volume733en_US
dc.identifier.issue1en_US
dc.identifier.startpage52en_US
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