Reduction of the Mass of the Proto-Quark Star during Cooling
Round 1
Reviewer 1 Report
\documentstyle[12pt]{article}
\textwidth 160 mm
\textheight 225 mm
\topmargin -25mm
\hoffset -1cm
\pagestyle{empty}
%\usepackage{color}
\begin{document}
\begin{center}
{\Large\bf {Referee report \\to the paper particles-986294 entitled\\
{\it "\textit{Reduction of the Mass of the Proto-Quark Star during
Cooling}" \\
by Gevorg Hajyan}}}
\end{center}
The author of the paper particles-986294 has studied the characteristics of two
models of proto-quark stars ($M_b = 1.22 M_\odot$ and $M_b = 1.62 M_\odot$) which
were formed after the explosion of the supernova, neglecting the changes
in the energy and lepton charge of the central regions of the pre-supernova star
during the implosion. The author has determined equation of state for hot quark matter
based on the MIT bag
theory taking into account the presence of neutrinos. The possible maximum values of the central
temperatures of these stars are also determined. The obtained energy of neutrinos in the studied proto-quark stars
is of the order of $250 - 300 \textrm{MeV}$. The author claims that decrease in the mass of these stars during cooling is about
0$.16 M_\odot$ for $M_b = 1.22 M_\odot$ and $0.25 M_\odot$ for $M_b = 1.22 M_\odot$.
The calculations performed are standard ones and correct (also are more idealistic), however, I have the following comments and suggestions:
i) The abstract of the paper has not been well written. The current form of the abstract looks like an introduction to the topic.
It would be better if the author could slightly revise the text of abstract in a form presenting the main results from the
main part of the paper.
ii) The conclusion is very short. I advise the author to summarize in detail the obtained results with discussions.
iii) The interior Schwarzschild spaacetime metric used in the study
has to be justified from the physical point of view.
iv) The quality of plots and figures does not meet the standards of the Particles journal and has to be improved.
v) More detailed analysis of the thermodynamic equilibrium conditions has to be performed towards
detailed description of the obtained results. For example, the chemical potential has not been discussed?
vi) Since the Particles journal is oriented on publication of the papers related to physics the author has to explore
possible astrophysical applications of the obtained results.
I do not think that the performed mathematical calculations
for the interior Schwarzschild spacetime would warrant a
publication in a high impact journal like the \textbf{Particles} specialized in publishing results
having physical and astrophysical importance in the revised form. At the mment
it really contains the mathematical results rather than
physical ones since the spacetime metric has undefined properties and no astrophysical application.
Physics behind these properties is not well defined and in the literature there are many regular solutions.
What is the advantage of using this one?
Since the study of this manuscript is mathematically correct and
indeed of interest in addressing the behaviour of the nonsingular black holes I would recommend to the author
to revise it along my comments and resubmit the revised version to journal. Then I would consider it for publication in the \textbf{Particles} journal.
I hope the revised paper would be suitable for publication in the \textbf{Particles} journal.
\end{document}
Author Response
Response to the comments of the reviewer No. 1
REFEREE-1: The abstract of the paper has not been well written. The current form of the abstract looks like an introduction to the topic. It would be better if the author could slightly revise the text of abstract in a form presenting the main results from the main part of the paper.
AUTHOR-1:
The abstract was has been rewritten according to referee’s recommendation.
REFEREE-2: The conclusion is very short. I advise the author to summarize in detail the obtained results with discussions.
AUTHOR-2:
Following the recommendation the conclusion section has been extended.
REFEREE-3: The interior Schwarzschild spacetime metric used in the study has to be justified from the physical point of view.
AUTHOR-3: I am using the standard Tolman-Oppenheimer-Volkoff (TOV) solutions for spherically symmetrical self-gravitating body. This is the standard approach in General Relativity. Of course, in case of rotation or magnetic fields the star will not be spherically symmetrical and these equations need to be replaced. However, many neutron star do not have large enough magnetic fields or do not rotate sufficiently fast, so that TOV equations are a very good approximation to the physical reality.
REFEREE-4: The quality of plots and figures does not meet the standards of the Particles journal and has to be improved.
AUTHOR-4:
The figure resolution has been enhanced.
REFEREE-5: More detailed analysis of the thermodynamic equilibrium conditions has to be performed towards detailed description of the obtained results. For example, the chemical potential has not been discussed?
AUTHOR-5:
Indeed, the questions of thermodynamic equilibrium between quarks and leptons in hot quark matter are not discussed in the article. This is given in our previous work and we do not want to repeat the details here. We have added at line 82 the following statement. „Further details on the particle composition of matter composed of quarks and leptons, the condition of thermodynamical equilibrium among their chemical potentials within the MIT model used in this work can be found in Refs. \cite{24,25}.“
REFEREE-6: Since the Particles journal is oriented on publication of the papers related to physics the author has to explore possible astrophysical applications of the obtained results.
AUTHOR-6: We have extended the conclusions of the paper, pointing out that a full understanding of the effect of reduction of the mass should come from numerical simulations of collapse and proto-quark star early evolution. There are no direct observations of these stages of evolution of compact stars and a comparison to the observations cannot be made. Nevertheless, the effect described in this work is not trivial and should motivate researchers to look into astrophysical applications.
Thank you for reviewing my article. I am sending the modified article. The yellow highlights indicate the changes.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this manuscript, the author solves numerically the relativistic equations of hydrostatic equilibrium, assuming a simple MIT bag model equation of state for quark matter. I would recommend this manuscript for the publication of particles after minor modifications. I have a few questions which may be included to improve the quality of the manuscript:
1) What are the reasons to select particular values of Mb=1.22, 1.62?
2) Can you tell us the minimum possible mass to create a proto-quark star?
3) In reality, the quark-gluon interaction constant alphac must be a finite value,
what will you expect if you set a finite value instead of setting zero?
Is it hard to perform a calculation with finite values of alphac?
Author Response
Response to Reviewer 2 Comments
Point 1: What are the reasons to select particular values of Mb=1.22, 1.62?
Response 1:
The mass value of the first star ( 1.22Msun. ) was chosen in a way that the stage of the ud phase of the quark matter in its central region was formed.
The maximum mass value for the selected values of the parameters of the MIT bag theory is 1.63Msun. The mass value of the second proto-quark stars ( 1.62Мsun ) is chosen close to this value.
Point 2: Can you tell us the minimum possible mass to create a proto-quark star?
Response 2:
The less is the mass of the collapsing core of the pre-supernova
star, the less is the mass of the ud quark core. Note that the minimum value of the
mass of the collapsing core of the PQS at which the ud quark phase
is still formed coincides with the value of the PQS mass that can be
formed in the supernova explosion ( line 186 in text ). The precise value of this limit
can be obtained only through detailed numerical computations.
Point 3: In reality, the quark-gluon interaction constant alphac must be a finite value,
what will you expect if you set a finite value instead of setting zero?
Is it hard to perform a calculation with finite values of alphac?
The simultaneous taking into account of the nonzero values of alphac and the mass of the strange quark complicates only the determination of the thermodynamic characteristics of hot strange quark matter ( HSQM ).
This can be done, but I think it is better to do a similar study with a more realistic HSQM equation of state instead, which is of course a more complicated task.
Thank you for reviewing my article. I am sending the modified article. The yellow highlights indicate the changes.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
\documentstyle[12pt]{article}
\textwidth 160 mm
\textheight 225 mm
\topmargin -25mm
\hoffset -1cm
\pagestyle{empty}
%\usepackage{color}
\begin{document}
\begin{center}
{\Large\bf {Referee report \\to the revised version to paper particles-986294 entitled\\
{\it "\textit{Reduction of the Mass of the Proto-Quark Star during
Cooling}" \\
by Gevorg Hajyan}}}
\end{center}
The author of the revised version of paper particles-986294 has made the requested modifications
along the comments provided in my report.
The study of this manuscript is mathematically correct and
indeed of interest in addressing the behaviour of the nonsingular black holes. I recommend
the revised version of the submitted paper for publication in the \textbf{Particles} journal
since it is suitable for publication in the \textbf{Particles} journal.
\end{document}
Comments for author File: Comments.tex
