The Low-Energy Spectral Index of Gamma-ray Burst Prompt Emission from Internal Shocks
Round 1
Reviewer 1 Report
The comments and suggestions can be found in the attached document.
Comments for author File: 
Comments.pdf
Author Response
Dear referee,
We appreciate you for the helpful suggestions and comments, following which we have revised the manuscript. We apologize for that we realized the revision should be marked using “Track changes” function after all revisions have been finished by us. However, all revisions are shown in boldface and we hope the changes can be easily found.
A point-by-point response can be found in the attachment. Please see the attachment.
with best regards,
Kai Wang and Zi-Gao Dai
Author Response File: Author Response.pdf
Reviewer 2 Report
The authors consider the internal shock model and reexamine the fast cooling of electrons in an evolutionary magnetic field. Most of the equations and formulations have already been in the literature. And a decreasing magnetic field model has also been worked out in Uhm & Zhang 2014. Even so, the time-dependent magnetic field consideration is interesting and seems to explain the spectral features of GRBs. I think overall the work is interesting and deserves publication after a couple of aspects are answered/improved:
A. Most of the equations in the paper are from Wang & Dai (2013), Uhm & Zhang (2014), and Uhm et al (2012). Please cite these references properly so that the readers can find detailed derivations of these equations.
B. Explain more clearly how your work differs from Uhm & Zhang's paper. Uhm & Zhang have considered decaying magnetic field ( varying as a function of distance from the central region), whereas the authors consider the time-dependent magnetic field. Is there some connection? Can a time-dependent magnetic field be translated to distance-dependent and vice-versa? Please add more text to explain.
C. Consider separating the proposed model formulation and its application to actual GRBs. There should be a result section, after formulating their model, the authors can show the fits to actual GRBs in the results section. Also, consider tabulating all the fitting parameters for two GRBs in the result section.
D. There are many parameters in the model. Please discuss the generality of the method. How well the model can fit any GRB spectrum in general. Deduce/discuss the dependence of parameters in the model.
Other minor comments:
i) Mention how \gamma_A and gamma_A,2.5 related? from where numeric coefficients in equations 1, 9, 11, and so on comes?
ii) Improve the ordering of text in general. Section 3 contains most of the paper. Try listing the assumption and difficulties of the model clearly someplace.
iii) Show uncertainty of the data points and fitted curve in figures 4 and 6. Consider plotting 1 sigma confidence intervals for time-averaged spectrum and plot error bars of the data points.
iv) It is not clear to me how authors obtain the fit shown in figures 4 and 6. That is how they tune parameters to match the observed spectrum?
Author Response
Dear referee,
We appreciate you for the helpful suggestions and comments, following which we have revised the manuscript. We apologize for that we realized the revision should be marked using “Track changes” function after all revisions have been finished by us. However, all revisions are shown in boldface and we hope the changes can be easily found.
A point-by-point response can be found in the attachment. Please see the attachment.
with best regards,
Kai Wang and Zi-Gao Dai
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
I am happy with the revised draft and recommend publication in Galaxies Journal as a regular article.
