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Multi-frequency Scatter-broadening Evolution of Pulsars. II. Scatter-broadening of Nearby Pulsars
- Source :
- The Astrophysical Journal. 878:130
- Publication Year :
- 2019
- Publisher :
- American Astronomical Society, 2019.
-
Abstract
- We present multi-frequency scatter broadening evolution of 29 pulsars observed with the LOw Frequency ARray (LOFAR) and Long Wavelength Array (LWA). We conducted new observations using LOFAR Low Band Antennae (LBA) as well as utilized the archival data from LOFAR and LWA. This study has increased the total of all multi-frequency or wide-band scattering measurements up to a dispersion measure (DM) of 150~pc\,cm$^{-3}$ by 60\%. The scatter broadening timescale ($\tau_{sc}$) measurements at different frequencies are often combined by scaling them to a common reference frequency of 1\,GHz. Using our data, we show that the $\tau_{sc}$--DM variations are best fitted for reference frequencies close to 200--300\,MHz, and scaling to higher or lower frequencies results in significantly more scatter in data. We suggest that this effect might indicate a frequency dependence of the scatter broadening scaling index ($\alpha$). However, a selection bias due to our chosen observing frequencies can not be ruled out with the current data set. Our data did not favour any particular model of the DM -- $\tau_{sc}$ relations, and we do not see a statistically significant break at the low DM range in this relation. The turbulence spectral index ($\beta$) is found to be steeper than that is expected from a Kolmogorov spectrum. This indicates that the local ISM turbulence may have a low wave-number cutoff or presence of large scale inhomogeneities in the line of sight to some of the reported pulsars.<br />Comment: Accepted for publication in ApJ
- Subjects :
- High Energy Astrophysical Phenomena (astro-ph.HE)
Physics
Spectral index
Line-of-sight
010504 meteorology & atmospheric sciences
Scattering
Astrophysics::Instrumentation and Methods for Astrophysics
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics
LOFAR
Low frequency
01 natural sciences
Pulsar
Space and Planetary Science
0103 physical sciences
Cutoff
Astrophysics - High Energy Astrophysical Phenomena
010303 astronomy & astrophysics
Scaling
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 15384357
- Volume :
- 878
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal
- Accession number :
- edsair.doi.dedup.....2922e7125b8a1fa7e9df1f91aa7877cd