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Article
Peer-Review Record

Estimate for the Neutrino Magnetic Moment from Pulsar Kick Velocities Induced at the Birth of Strange Quark Matter Neutron Stars

Universe 2024, 10(7), 301; https://doi.org/10.3390/universe10070301
by Alejandro Ayala 1,*,†, Santiago Bernal-Langarica 1,† and Daryel Manreza-Paret 2,†
Reviewer 1: Anonymous
Reviewer 2: Anonymous
Universe 2024, 10(7), 301; https://doi.org/10.3390/universe10070301
Submission received: 14 June 2024 / Revised: 11 July 2024 / Accepted: 17 July 2024 / Published: 20 July 2024
(This article belongs to the Special Issue Studies in Neutron Stars)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper discusses the constraints that can be set to the neutrino magnetic moment from pulsar kick velocities, based on the assumption that these kick velocities arise from neutrino chirality flip in the core of a strange quark neutron star. 

Overall the paper is well written and scientifically sound. I have a few points that could be addressed in a revised version of the paper:

1. In line 31 the authors write about cooling of neutron stars that [they cool]... "to an almost vanishing temperature". While the temperatures are indeed much lower than the MeV levels estimated early in NS stars lives, they are far from vanishing, as several middle-aged neutron stars have keV temperatures. The authors should moderate this claim.

2. The question of pulsar kick velocities has puzzled the astrophysical community for quite some time. A more comprehensive discussion of the relevant references is desirable, as the authors could mention the seminar paper of Harrison and Tademaru 1975, Nature, Volume 254, Issue 5502, pp. 676-677 (1975), and some more recent progress both observational and theoretical: Igoshev et al. 2021, Monthly Notices of the Royal Astronomical Society, Volume 508, Issue 3, pp.3345-3364, Agalianou and Gourgouliatos 2023, Monthly Notices of the Royal Astronomical Society, Volume 522, Issue 4, pp.5879-5891. 

3. The authors need to define all the symbols that appear in the equations, even if some notation is standard. This would be important for the broad readership of the journal, since the paper may be of interest to the observational astronomers who are not very familiar with nuclear physics (i.e. they should clarify the meaning of \gamma_5, /P, /K). 

4. In equation 17, the velocity appears with 6 significant digits (803.925) whereas the other quantities (i.e. neutron star mass and radius) have two significant digits. Some rounding to the expected accuracy is required (i.e. 800km/s)

5. The occurrence of quark matter is more likely in high mass neutron stars as stated by the authors in lines 135 - 142. Does this mean that this model is applicable only to such sources? The authors should provide some clarification on that issue, as several neutron stars have masses close to the 1.4 M_{\odot}. Would this imply that the fastest neutron stars would also be the heaviest ones?

6. In the summary and discussion section, the authors could put their mechanism in the broad context of other works. Could this effect co-operate, compete or work completely independently with other mechanisms? Could it also provide some spin-velocity alignment, as it has been observed in several sources (i.e. Noutsos et al. 2012, Monthly Notices of the Royal Astronomical Society, Volume 423, Issue 3, pp. 2736-2752, Yao et al. 2021, Nature Astronomy, Volume 5, p. 788-795).

 

 

There is a typo in line 72, duplicated "and and".

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In this article, the author addresses the estimation of the magnetic moment of electron neutrinos by computing the neutrino chirality flip rate that can occur in the core of a strange quark matter neutron star at birth. This process eventually allows neutrinos to escape anisotropically, thereby inducing the star's kick velocity. They have thoroughly analyzed the phenomena have given a new bound known to the community of the neutrino magnetic moment. 

 

I would like to warrant the publication of the article after they clarify the following query:

Although they have considered the debye mass of the photon in amidst the thermal plasma. In the similar fashion the neutrino's will also have a debye mass. It would be really helpful is the author could comment on the inclusion of left- and right-handed neutrino thermal masses in the analysis.

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have fully addressed my comments in the previous version and I am happy to recommend the acceptance of their paper to the "Universe". 

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