Supermassive Black Holes from Bose-Einstein Condensed Dark Matter—Or Black and Dark Separation by Angular Momentum

Round 1

Reviewer 1 Report

Please see the attached file.

Comments for author File: Comments.pdf

Author Response

I appreciate your comments and suggestions which were quite useful for my revision. I agree that all of the comments are correct and therefore I tried to improve the previous version as much as I can. In particular, I included a new section 5 Observational verification, to meet your suggestion emphasizing the astrophysical observability/justifications. I believe this new version is fully revised and well suited for publication. Thank you again for your precise 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 authors could revise the text of abstract in a form presenting the main results from the main part of the paper.

Abstract has been fully revised including all the main results in this paper, including the observational verifications.  

ii) The conclusion is written in the way which needs more astrophysical justifications then making the future prospects with the detailed plan. I advise the author to summarize in detail the main obtained results with the discussions on their astrophysical observability.

The conclusion has been fully revised including the astrophysical implications based on the newly added section 5 Observational Verification.

iii) The quality of plots and figures does not meet the standards of the Universe journal and has to be definitely improved.

I have improved all the figures including the coloring, plots, and trimming. In particular, minimizing the use of color and make it consistent in figures 1 and 2.  

iv) Since the Universe journal is oriented on publication of the papers related to physics the author has to explore possible astrophysical applications of the obtained results in more concrete way.

I added the new section 5 Observational Verification, for this purpose. I compared the estimated SMBH/DH mass ratio with the recent observation [35] as well as classic [36]. It turns out that our estimate is not excluded by the observations although the observational data has a large scatter and therefore allows a wide range of predictions. I newly learned that the mass ratio reduces 1-2 digits from z=6 to z=0. Thus, the key point of comparison with observational data and the verification of our scenario has become clear.

v) Good fraction of the text of the submitted paper mainly repeats the scientific results which have been published by the author in the recent paper published in Proceedings (2019) 13, 11; doi:10.3390/proceedings2019013011 entitled ”Supermassive Black Holes and Dark Halo from the Bose-Condensed Dark Matter”.

I have removed most of the overlaps except some equations which are needed as the base of the present discussions in the paper.

 

 

Modifications:

1. The title is slightly modified.
2. The abstract is fully revised including all the main results in this paper and the mention of the observational verifications.
3. The entire part of the paper has been improved, in particular, the English presentation is corrected by using grammar and spell checkers.
4. All the figures are improved, including the coloring, plots, and trimming. In particular, minimizing the use of color and make the use of color consistent in figures 1 and 2.
5. Many relevant references are added in the entire part of the revised version.
6. Duplicated equations and descriptions are removed and modified, in particular, at the basic setup of the main discussions.
7. Motivation to consider the BEC-DM for the formation of SMBH is more emphasized using the cosmic magnetic field scaling (Fig.1).  
8. Section 5 Observational Verification, is newly added and the verification of our estimate for the mass ratio SMBH/DH is discussed.
   
   
9. Section 6 conclusion and discussions are modified to include more astrophysical aspects reflecting the new section 5.

 

Reviewer 2 Report

The author proposes to explain the formation of supermassive black holes in the early Universe as the collapse of Bose-Einstein condensates, which should also be the dark matter. The article is purely speculative, as it is well-known that there is no observational/experimental evidence of dark matter, despite decades of observations and experiments [at least, the author proposes Bose-Einstein condensates, which were experimentally observed, as candidate for dark matter, and does not search for some exotic and fictitious particle]. Nonetheless, this essay has its own consistency and, therefore, deserves the publication. It just requires an extensive language editing, because the English grammar is quite sloppy. 

Author Response

I appreciate your comments which were quite useful for my revision. I agree that the arguments in this paper are purely speculative. Since I want to make it more real, I added a new section 5 Observational verifications, which provides some Physical aspects beyond pure speculations.

Further, English has been fully revised in the entire part of this paper, I hope.

I believe this new version is fully revised and well suited for publication. Thank you again for your valuable suggestions.

 

 

 

Modifications:

1. The title is slightly modified.
2. The abstract is fully revised including all the main results in this paper and the mention of the observational verifications.
3. The entire part of the paper has been improved, in particular, the English presentation is corrected by using grammar and spell checkers.
4. All the figures are improved, including the coloring, plots, and trimming. In particular, minimizing the use of color and make the use of color consistent in figures 1 and 2.
5. Many relevant references are added in the entire part of the revised version.
6. Duplicated equations and descriptions are removed and modified, in particular, at the basic setup of the main discussions.
7. Motivation to consider the BEC-DM for the formation of SMBH is more emphasized using the cosmic magnetic field scaling (Fig.1).  
8. Section 5 Observational Verification, is newly added and the verification of our estimate for the mass ratio SMBH/DH is discussed.
9. Section 6 conclusion and discussions are modified to include more astrophysical aspects reflecting the new section 5.
   
   

Reviewer 3 Report

In this paper,  the authors study  supermassive black holes formed by the gravitational collapse of the coherent dark matter (DM) composed
 from the Bose-Einstein Condensed (BEC) objects. What makes significant the manuscript is the discussion on  the DM forming SMBH and also they have used several analytic approximations without well examining the validity. In particular, it is shown that the assumption of the density profile has drastically changed the mass of the formed SMBH. Thus the angular momentum naturally separates the original DM cluster into the central SMBH and the surrounding DH. Therefore, I recommend the paper for publication in Universe.

Author Response

I appreciate your valuable comments. I agree that several approximations used in this paper lack sufficient examination of validity. The precise formulae are desired, but it requires elaborate numerical calculations including general relativity. Therefore, postponing this argument to my future work, I newly added a new section 5 Observational Verifications, which provides some Physical aspects beyond pure mathematical approximations.

Further, English has been fully revised in the entire part of this paper, I hope.

I believe this new version is fully revised and well suited for publication. Thank you again for your valuable comments.

 

Modifications:

1. The title is slightly modified.
2. The abstract is fully revised including all the main results in this paper and the mention of the observational verifications.
3. The entire part of the paper has been improved, in particular, the English presentation is corrected by using grammar and spell checkers.
4. All the figures are improved, including the coloring, plots, and trimming. In particular, minimizing the use of color and make the use of color consistent in figures 1 and 2.
5. Many relevant references are added in the entire part of the revised version.
6. Duplicated equations and descriptions are removed and modified, in particular, at the basic setup of the main discussions.
7. Motivation to consider the BEC-DM for the formation of SMBH is more emphasized using the cosmic magnetic field scaling (Fig.1).  
8. Section 5 Observational Verification, is newly added and the verification of our estimate for the mass ratio SMBH/DH is discussed.
9. Section 6 conclusion and discussions are modified to include more astrophysical aspects reflecting the new section 5.
   
   

 

 

 

Reviewer 4 Report

The author considers the scenario in which SMBHs form from collapse of BEC dark matter. The scenario faces the problem that angular momentum can prevent the collapse. The authors proposes that angular momentum acquisition in very early times from the tidal torque mechanism alleviates the problem.

First of all, the BEC DM is only one of the hypotheses for DM and has been studied for a very long time. At least the author should briefly explain its advantage over other popular DM candidates and the major development status of the scenario (and cite more papers in the field). In the 3rd paragraph in Introduction, "... coherent BEC matter which is supposed to provide the dark matter", the author ignores other dark matter candidates.

Without the background, the paper is at least not well motivated.

Second, the paper seems like a math exercise without comparison to observations. The author acknowledged that the estimates are based on bold approximations. But there should be some order-of-magnitude comparison to observations at least to demonstrate the validity of these estimations. Normally, it wouldn't need GR to do such comparisons.

I do not recommend to publish in the draft's current form.

Author Response

I appreciate your comments and suggestions which were quite useful for my revision.

I expanded the third paragraph in the Introduction and tried to clarify the BEC-DM in a wider context of the scalar-field DM. The class of DM is quite wide and the full description is difficult. Therefore, I tried to include many relevant references as much as possible. If not sufficient, please let me know, I’m willing to rewrite this part.  

 

The arguments in this paper may indeed seem to be a math exercise as you correctly point out. Therefore, I included a new section 5 Observational Verification, to meet your comments.

It turns out that our estimate is not excluded by the observations although the observational data has a large scatter and therefore allows a wide range of predictions.

I believe this new version is fully revised and well suited for publication. Thank you again for your valuable comments and suggestions.

 

 

Modifications:

1. The title is slightly modified.
2. The abstract is fully revised including all the main results in this paper and the mention of the observational verifications.
3. The entire part of the paper has been improved, in particular, the English presentation is corrected by using grammar and spell checkers.
4. All the figures are improved, including the coloring, plots, and trimming. In particular, minimizing the use of color and make the use of color consistent in figures 1 and 2.
5. Many relevant references are added in the entire part of the revised version.
6. Duplicated equations and descriptions are removed and modified, in particular, at the basic setup of the main discussions.
7. Motivation to consider the BEC-DM for the formation of SMBH is more emphasized using the cosmic magnetic field scaling (Fig.1).  
8. Section 5 Observational Verification, is newly added and the verification of our estimate for the mass ratio SMBH/DH is discussed.
9. Section 6 conclusion and discussions are modified to include more astrophysical aspects reflecting the new section 5.
   
   

Round 2

Reviewer 1 Report

Referee report to the revised paper universe-1292919-v2 entitled
"Supermassive Black Holes from Bose-Einstein
Condensed Dark Matter
- or Black and Dark Separation by Angular Momentum -"
by Masahiro Morikawa

 

The author has extensively revised original submission along my comments and resubmitted the revised version to the journal.
I believe the revised paper is suitable for publication in the UNIVERSE journal and recommend it for acceptance.