GRB 181110A: Constraining the Jet Structure, Circumburst Medium and the Initial Lorentz Factor

Round 1

Reviewer 1 Report

The authors present a complete analysis of the early afterglow and the energetics of this GRB. In particular, they underline the importance of determining the initial Lorentz factor. They clearly show that this GRB is a typical long GRB.

My comments, all average and minor, are listed below.

l. 23-34
Note that Panaitescu and Kumar (2020, ApJ, 543, 66)
show that the Lorentz factor at the decelarion radius is half of the 
initial Lorentz factor (see their eq. 1). This is also pointed out
in Molinari et al A&A 2007, 469, L13.

l. 38-39 specify that you do this ofr GRB 181110A. I thin a one sentence 
introducing this GRB here would be nice.

l. 49 138->138.4? In general, please use the same digits.
    see GCN 23420.

Fig. 3. Specify what the red data-points are.

l. 89 peak time -> peak time ($t_p$)    

l. 94 Please specify the values of Galactic extinction 
    A_V and absorption N_H (reference included)

l. 96 Error on the derived A_V please. OR explain why you 
    do not give an error. Or maybe this is an upper limit?

l. 99 Please, give a reference for the online repository

Table 2: A value of K~12 is quite large and indeed the peak 
    is very sharp. You should consider to use a smaller value 
    (smoother), like k~1. Or use the value that you find fitting 
    the X-ray only, which has a better sampling.

Fig 5 If the drop in flux between uvw1 abd uvm2 is because
       of Lyman alpha absoprition at the redshift of the burst,
       please specify this (in the tet, too.) Then you could 
       avoid considering the uvm2 and uvw2 points 
       in the SED fitting.

l. 115 of listed -> listed

l. 115 Table 2 is -> Table 2 are

Author Response

Dear reviewer!

Thank you for your comments!

1. We added that the Lorentz factor at the decelarion radius is half of the 
   initial Lorentz factor.
2. We added one sentence introducing GRB 181110A.
3. We fixed 138 to 138.4.
4. We modified as you comment.
5. We specify the values of Galactic extinction A_V (E(B−V) =0.0613)and absorption N_H(5.51×1015cm−2)
6. We added the error on the derived A_V(+-0.01)
7. We added the reference for the online repository.
8. Sorry but we consider it a bit hard to change as the value of k is the result of our fit, if we fix it to 1, the fitting result would be affected. 
9. We specified the Lyman alpha absorption both in caption and text.
10. We fixed the grammar mistakes.

Reviewer 2 Report

The article "GRB 181110A: Constraining the Jet Structure, Circumburst Medium and the Initial Lorentz Factor" analyzed thoroughly the GRB 181110A, multiband light curve, prompt as well as the afterglow spectra, modelling the afterglow, deriving the initial Lorentz factor, and put this GRB into the statistics. It is a comprehensive analysis to a single GRB, and worth to be published. 

Some comments might be addressed:

The authors have separately given the spectra for X-ray itself (Table 1) and both X-ray and optical band ($3.3). It is worth a combination discussion for these two.

As shown in Figure 4, the whole lightcurve, from ~600s to 5e4s, shows no frequency crossing. The authors should discuss whether their parameters are consistent with the case nu_m

line 44, reference of the cosmological parameters should be given
Figure 3, which is which should also be given in the caption.
Figure 5, x-axis
Figure 7, the origin of the data should be given.
correlation functions in Figures 7 & 8 should be given in captions and in text.

The units in the figures should be in correct form.

The subscripts should be in proper fonts.

Author Response

Dear reviewer

Thanks for your comments!

1. We combined the spectral analysis of the prompt and afterglow emission.
2. With the parameters in Table 3, we estimate the typical frequencies to be ν_m~10¹²Hz and ν_c~10¹⁹Hz, thus consistent with our analysis above.
3. We cited the reference.
4. We added the description in the caption.
5. We fixed the x-axis in Figure 5.
6. We gave the origin of the data of Figure 7 and gave correlation functions in Figures 7 & 8  in captions and in text.
7. We fixed the units and subscripts.