LAMOST Spectroscopy and Gaia Photo-Astrometry for an Interstellar Extinction Study
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsMore careful consideration and calculations, and explicit explanations would be helpful in order to make the results convincing.
Comments for author File: 
Comments.pdf
reasonable
Author Response
Dear reviewer,
We thank you for extremely useful and constructive comments, they greatly helped us to improve the paper.
We have made all required corrections and responded all questions raised.
All changes are highlighted in blue in the text.
The details of the revisions are given below, point-by-point.
Please, note that corrections required by other reviewers are also made and highlighted in the text.
We are ready to answer your questions if you still have them.
Thank you very much again for your cooperation,
With best regards,
Oleg Malkov
The following statements and poins need additional corrections and explanations:
l. 54: I agree with the authors statement that they assume that (1) satisfactory reproduces...
==> You are absolutely right.
In its original form (Parenago 1940) it was a simple model, because a0 and beta were constants.
However, in subsequent publications (and our publication among others), a0 and beta are treated
as functions of galactic coordinates, they are no longer constants.
We quite agree with your point about small distances,
but in this paper we are primarily interested in the result at large distances.
We hope that our approximation gives sufficiently reliable results.
ll. 126-143: The agreement between Agal and Ax in Figure 7 does not seem exactly a good one...
==> That's a perfectly fair observation.
However, we do not see a _systematic_ shift of A_{gal} relative to A_X
and tend to attribute the differences between them to the low precision of both values.
Actually, the main idea of this figure (and one of the main ideas of the paper)
is that the existing accuracy of the estimate of interstellar extinction does not allow us
to draw more definite conclusions today.
Particularly the statement on line 143 needs explanations...
==> It is just an illustration that the G23 model is very different from all the others.
We cannot afford to make more drastic statements in our paper.
ll. 149-153: 42 sightlines shown in Table 1 present both northen and southern galactic
latitudes as can be judged by the signs of b. The authors are to be more precise in their
wordings in order not to confuse readers, particularly in the Conclusion.
==> Thank you very much. The beginning of the section Conclusion is corrected.
Some minor points:
page 1, Eq 1: The extinction is shown as a function of only b (galactic latitude)...
==> Yes, that's our inaccuracy too. See my comment on your first point (above).
The definition of d and b has been added to the text.
l. 131-132: the statement "..studied, AV (SF11) = AV (SFD98)/0.m03. For a number
of areas, the denominator reaches a value of 0.m06" sounds irrelevant without special
explanations.
==> The second phrase is removed from the text.
It is not very important for this study
l. 135: the term "Stilist service" should be clearly explained.
l. 136: "Silism" should be replaced with "STILISM project" with capital as in original paper.
==> I am sorry, "Silism" is a misprint, now it is corrected.
"STILISM" (now it is capitalized as you recommend) is the name of the service, described in Lallement et al. 2018,
and we have no idea on the origin of this name.
=============================================================
Reviewer 2 Report
Comments and Suggestions for AuthorsSee the document for details.
Comments for author File: Comments.pdf
English needs a small correction.
Author Response
Dear reviewer,
We thank you for your extremely useful and constructive comments, they greatly helped us to improve the paper.
We have made all required corrections and responded to all questions raised.
All changes are highlighted in orange in the text.
The details of the revisions are given below, point by point.
Please, note that corrections required by other reviewers are also made and highlighted in the text.
We are ready to answer your questions if you still have them.
Thank you very much again for your cooperation,
With best regards,
Oleg Malkov
1. The methodology section would benefit from a more comprehensive description of
the data processing steps, including the cross-identification procedure between
LAMOST and Gaia objects.
==> A paragraph with more details and Fig.2 are added to Section 2.1.
2. The authors conducted a regression analysis based on the extinction classical
exponential model for an isotropic semi-infinite thick absorbing layer, as defined by
equation (1) and the three distance intervals illustrated in Fig. (2), and obtained the
parameters a_0 and \beta. It would be beneficial to ascertain whether these are the
same. The authors should provide the specific parameters and engage in a detailed
discussion thereof.
==> Section 2.2 with the description of the obtaining parameters process is added.
3. While the error budget analysis is comprehensive, it would benefit from a
discussion on how these errors propagate through the final estimates of galactic
extinction and how they might affect the interpretation of the results.
==> As can be seen from Table 1, the errors of the Agal values lie between 0.004 and 0.082 (Mean=0.022, SD=0.025),
and we can only be responsible for results within this corridor.
Within these errors, our results are in good agreement with Ax values (Perlmutter et al. 1999).
3. To strengthen the comparison with other maps and studies, a more detailed analysis
of the systematic differences observed is required, including a discussion on the
potential sources of these discrepancies and their implications for the accuracy of
distance measurements to extra-galactic objects.
==> The analysis of comparison with STILISM data (Fig. 10) is given in Section 3.3:
STILISM provides a 3D map of interstellar extinction, and, as a consequence,
STILISM values do not exceed our Agal values.
As to the comparison with Gontcharov et al's values (Fig. 11), we could assume the following.
Gontcharov et al. 2023 demonstrate a satisfactory agreement of their results
both with SFD98 (Schlegel et al. 1998) and with SF11 (Schlafly and Finkbeiner 2011).
Our results are also in good agreement with SF11 (Fig. 9), but not in agreement with Gontcharov (Fig. 11).
The only reason for that we can suggest is that we deal with high-latitude areas, and Gontcharov et al study all the sky.
Probably, Gontcharov et al. overpredict extinction for high latitudes and underpredict for low latitudes.
4. In response to the manuscript's page 6, lines 128-131, the reader will wish to
ascertain why there may be a systematic overestimation of A_gal values in
comparison to more recent maps such as A(SFD11), and what could be the potential
reasons for this discrepancy. Furthermore, it would be beneficial to determine whether
there are any documented methods for correcting this overestimation in the literature.
==> A discussion is added at the end of Section 3.2.
5. In fig.5, the authors examine the calculation of standard deviations (SD) of model
parameters using the lmfit package, which relies on the covariance matrix obtained
from the minimization procedure. It is acknowledged that in certain instances, the
calculation of SD may be unfeasible due to factors such as the poor conditioning of
the covariance matrix, the use of inaccurate initial values, the lack of sufficient data,
or the presence of high noise levels, which are attributed to the inferior quality of the
data. In order to address these challenges, the author may advised to consider utilizing
Monte Carlo simulations as a means of estimating the standard deviations. Monte
Carlo simulations have the potential to provide a more robust estimation of parameter
uncertainties, particularly in scenarios where the conditioning of the covariance
matrix is inadequate or when the quality of the data is insufficient.
==> We have addressed the issue by performing Monte Carlo simulations of the temperature,
as we believe most of the uncertainty arises from this factor.
This analysis is presented at the beginning of Section 2.3.
The results show that only minor changes occur in $A_{gal}$, even though individual $A_V$ values
may vary significantly. Additionally, we do not use these estimations or the standard deviations
calculated by lmfit directly. Instead, we combine both types of errors (see Eq. 5),
which implies that the reported errors represent an upper limit on the actual errors of the method.
English needs a small correction.
==> Some corrections are made.
Reviewer 3 Report
Comments and Suggestions for AuthorsGeneral comments:
This paper presents and interstellar extinction study, which might be valuable to readers if the work is explained better. (it is not useful in its current form).
Detailed comments:
line 16: need to define d (distance from what). Do you mean no dependence on galactocentric radius? If so, I think the model is much simpler than other published models and is not appropriate (not very useful).
If you are limiting to only nearby stars you should state this (and change title of paper appropriately) and explain the limit.
line 22: it depends strongly on extinction also. Maybe you mean photometry without extinction (should be stated).
Fig.2: the examples shown look like they are poor fits, in particular the model line does not go through the points for small distance but is above the points. Thus it looks like a systematic error would result in your derived extinctions.
Fig.6 : it looks like AV vs AX not what you state in the caption (?what does 20 mean?. Please correct.
section 3.3: "Stilism" or "Silism" I don't know what this means. Please explain.
section 3.4: "decrease in the distance to the extragalactic object" makes no sense; please explain what you mean.
section 4:
the extinction has nothing to do with the accelerated expansion of the Universe (unless you can explain why).
Comments on the Quality of English LanguageThe English language needs editing grammar needs correction in many places.
e.g. title: "for the interstellar" should be "for an interstellar"
abstract line 2 " in the selected" should be "in selected"
Author Response
Dear reviewer,
We thank you for extremely useful and constructive comments, they greatly helped us to improve the paper.
We have made all required corrections and responded all questions raised.
All changes are highlighted in blue in the text.
The details of the revisions are given below, point-by-point.
Please, note that corrections required by other reviewers are also made and highlighted in the text.
We are ready to answer your questions if you still have them.
Thank you very much again for your cooperation,
With best regards,
Oleg Malkov
Detailed comments:
line 16: need to define d (distance from what). Do you mean no dependence on galactocentric radius?
If so, I think the model is much simpler than other published models and is not appropriate (not very useful).
==> You are absolutely right.
In its original form (Parenago 1940) it was a simple model, because a0 and beta were constants.
However, in subsequent publications (and our publication among others), a0 and beta are treated
as functions of galactic coordinates (i.e., galactocentric radius is taken into account).
The definition of d has been added to the text.
If you are limiting to only nearby stars you should state this (and change title of paper appropriately)
and explain the limit.
==> We are limited to Gaia stars (and this is reflected in the title of the paper).
We hesitate to call them nearby stars, since the distances to some of them are a few kpc.
line 22: it depends strongly on extinction also. Maybe you mean photometry without extinction (should be stated).
==> Again you are right, it depends on extinction as well. Actually we mention this a few lines below.
Fig.2: the examples shown look like they are poor fits,
in particular the model line does not go through the points for small distance but is above the points.
Thus it looks like a systematic error would result in your derived extinctions.
==> We would like to draw your attention to the fact that we do not approximate with an arbitrary function,
but with a barometric function (Eq.(1)), so the result is sometimes non perfect.
In addition, we are primarily interested in the result at large distances,
so we can ignore some discrepancy for nearby stars.
Fig.6 : it looks like AV vs AX not what you state in the caption (?what does 20 mean?. Please correct.
==> I am sorry. The caption is corrected.
section 3.3: "Stilism" or "Silism" I don't know what this means. Please explain.
==> I am sorry once more. "Silism" is a misprint, now it is corrected.
"Stilism" is the name of the service, described in Lallement et al. 2018,
and we have no idea on the origin of this name.
section 3.4: "decrease in the distance to the extragalactic object" makes no sense; please explain what you mean.
==> You are right. We mean "decrease in the value of distance to the extragalactic object estimation". Corrected.
section 4:
the extinction has nothing to do with the accelerated expansion of the Universe (unless you can explain why).
==> Here we mean that a correct account of interstellar extinction is necessary
for a correct estimation of distances to SN Ia, by which the expansion rate of the Universe is estimated.
Comments on the Quality of English Language
The English language needs editing grammar needs correction in many places.
==> English revision was made by a native English speaker.
e.g. title: "for the interstellar" should be "for an interstellar"
==> Corrected.
abstract line 2 " in the selected" should be "in selected"
==> Corrected.
=================================================================
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsUnfortunately, your answer turned out to be rather formal and as such does not clarify my points much. My impression still is that in current form the manuscript does not look convincing for a reader. That's why my comments remain practically the same. In addition, I think a more explicit and clearly pronounced conclusion would also be desirable.
Comments on the Quality of English LanguageEnglish is quite reasonable and can require a minor corrections.
Author Response
Dear reviewer,
We thank you again for your extremely useful and constructive comments.
We understand that we should not only answer your questions but add these answers to the text.
Now the manuscript is changed significantly.
In particular, we have corrected Section 2.1, added Section 2.2 (and Fig.2), and added a paragraph in Section 3.2.
The details of our revisions are given below.
I hope all corrections you required are made in this or the previous round.
However, we are ready to answer your questions if you still have them.
All changes are highlighted in orange in the text.
Thank you very much again for your cooperation,
With best regards,
Oleg Malkov
The following statements and poins need additional corrections and explanations:
l. 54: I agree with the authors statement that they assume that (1) satisfactory reproduces...
==> A more detailed description of a0 and \beta is added in the Introduction.
Details of a0, \beta determination can now be found in Section 2.2.
ll. 126-143: The agreement between Agal and Ax in Figure 7 does not seem exactly a good one...
==> A discussion is added at the end of Section 3.2.
Particularly the statement on line 143 needs explanations...
==> As to the comparison with Gontcharov et al's values (now Fig. 11), we could assume the following.
Gontcharov et al. 2023 demonstrate a satisfactory agreement of their results
both with SFD98 (Schlegel et al. 1998) and with SF11 (Schlafly and Finkbeiner 2011).
Our results are also in good agreement with SF11 (Fig. 9), but not in agreement with Gontcharov (Fig. 11).
The only reason for that we can suggest is that we deal with high-latitude areas, and Gontcharov et al study all the sky.
Probably, Gontcharov et al. overpredict extinction for high latitudes and underpredict for low latitudes.
Comments on the Quality of English Language
English is quite reasonable and can require a minor corrections.
==> Some corrections are made.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe paper is improved but I did not find that the reviewer's adequately responded to the reviewer comments in all cases. E.g. they may have added a suitable response in their response letter, but did not make changes to the manuscript. A few changes to the manuscript are still required.
Detailed comments:
line 16: response: The definition of d is now given, but it should be added that \beta and a_0 are functions of galactic coordinates (and stated whether they are functions of 2D r and \phi or some other e.g. 3D like r,\phi,z). It looks like from lines 40-41 that they are constants within a given region of the sky. Please state that here.
line 53: to get total extinction you integrate, which is OK, but it means you are ignoring any inhomogeneities beyond the distance of the Gaia stars such as the high latitude cirrus. It would be useful to state this.
Author response to comment on Fig.2: please add this to the text of the paper "we are primarily interested in the result at large distances, so we can ignore some discrepancy for nearby stars"
line 133: you mean -0.03m not "divide"
Fig. 9: you should use the same notation for the Stilism values: either A(STILISM) or AV(st) but not both. Please change this so it is not confusing to the reader.
Comments on the Quality of English Language
Some minor editing (e.g. spelling in few places) is needed.
Author Response
Dear reviewer,
We thank you again for your extremely useful and constructive comments.
Now the manuscript is changed significantly.
In particular, we have corrected Section 2.1, added Section 2.2 (and Fig.2), and added a paragraph in Section 3.2.
We have also made all the corrections you required and responded to all questions raised.
The details of the revisions are given below, point by point.
All changes are highlighted in orange in the text.
We are ready to answer your questions if you still have them.
Thank you very much again for your cooperation,
With best regards,
Oleg Malkov
Detailed comments:
line 16: response: The definition of d is now given, but it should be added that \beta and a_0 are functions
of galactic coordinates (and stated whether they are functions of 2D r and \phi or some other e.g. 3D like r,\phi,z).
It looks like from lines 40-41 that they are constants within a given region of the sky. Please state that here.
==> The text is corrected.
line 53: to get total extinction you integrate, which is OK, but it means
you are ignoring any inhomogeneities beyond the distance of the Gaia stars such as the high latitude cirrus.
It would be useful to state this.
==> The text is corrected.
Author response to comment on Fig.2: please add this to the text of the paper
"we are primarily interested in the result at large distances, so we can ignore some discrepancy for nearby stars"
==> The text is added at the end of 1st par of Section 2.2 (and now it is Fig.3).
line 133: you mean -0.03m not "divide"
==> I am sorry, it was a wrong relation. The correct one is SF11 = 0.82 * SFD98. The text is corrected.
Fig. 9: you should use the same notation for the Stilism values: either A(STILISM) or AV(st) but not both.
Please change this so it is not confusing to the reader.
==> The figure is corrected (now it is Fig. 10).
Comments on the Quality of English Language
Some minor editing (e.g. spelling in few places) is needed.
==> Some corrections are made.
