Unraveling the Eclipse Mechanism of a Binary Millisecond Pulsar Using Broadband Radio Spectra. (arXiv:2107.13258v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Kansabanik_D/0/1/0/all/0/1">Devojyoti Kansabanik</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bhattacharyya_B/0/1/0/all/0/1">Bhaswati Bhattacharyya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Roy_J/0/1/0/all/0/1">Jayanta Roy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stappers_B/0/1/0/all/0/1">Benjamin Stappers</a>
The frequency dependent eclipses of the radio emission from millisecond
pulsars (MSPs) in compact binary systems provide an opportunity to understand
the eclipse mechanism and to determine the nature of the eclipsing medium. We
combine multifrequency observations from the upgraded Giant Metrewave Radio
Telescope (uGMRT) and model the broadband radio spectrum in the optically thick
to thin transition regime to constrain the eclipse mechanism. The best-fit
model to the eclipse phase spectra favors synchrotron absorption by
relativistic electrons. We are able to strongly constrain the frequency of
onset of the eclipse to 345$pm$5 $mathrm{MHz}$, which is an order of
magnitude more precise than previous estimates. The dependence on the magnetic
field strength of synchrotron absorption allowed us to estimate the magnetic
field strength of the eclipse medium to be $sim$13 $mathrm{G}$, which is very
similar to the values obtained by considering a pressure balance between the
incident pulsar wind and the stellar wind of the companion. Applying this
method to other millisecond binary pulsars will enable us to determine if the
eclipse mechanisms are all the same and also estimate the wind and magnetic
field properties of the companion stars. The method could also be applied to
other systems where pulsars interact with companion winds in binary systems and
in all cases it will lead to a better understanding of the evolutionary
processes.
The frequency dependent eclipses of the radio emission from millisecond
pulsars (MSPs) in compact binary systems provide an opportunity to understand
the eclipse mechanism and to determine the nature of the eclipsing medium. We
combine multifrequency observations from the upgraded Giant Metrewave Radio
Telescope (uGMRT) and model the broadband radio spectrum in the optically thick
to thin transition regime to constrain the eclipse mechanism. The best-fit
model to the eclipse phase spectra favors synchrotron absorption by
relativistic electrons. We are able to strongly constrain the frequency of
onset of the eclipse to 345$pm$5 $mathrm{MHz}$, which is an order of
magnitude more precise than previous estimates. The dependence on the magnetic
field strength of synchrotron absorption allowed us to estimate the magnetic
field strength of the eclipse medium to be $sim$13 $mathrm{G}$, which is very
similar to the values obtained by considering a pressure balance between the
incident pulsar wind and the stellar wind of the companion. Applying this
method to other millisecond binary pulsars will enable us to determine if the
eclipse mechanisms are all the same and also estimate the wind and magnetic
field properties of the companion stars. The method could also be applied to
other systems where pulsars interact with companion winds in binary systems and
in all cases it will lead to a better understanding of the evolutionary
processes.
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