Why Jet Power and Star Formation Are Uncorrelated in Active Galaxies

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I carefully read the manuscript “Why Jet Power and Star Formation Are Uncorrelated in Active Galaxies”. The authors investigate the possible correlation between jet power and star formation from a theoretical point of view. Their results are interesting and worth publishing after minor revision.

I include just a few minor comments that could be taken into consideration by the authors.

INTRODUCTION

line 20. For the sake of completeness, I suggest to add a few lines explaining in a simple way the definition on positive and negative feedback.

SECTION 2

Figure 1. I find this figure probably missing a few labels indicating some elements which are mentioned in lines 50-60. Currently, it simply shows the tilt of the accretion disk, but does not displays any information on the environment onto which the jet impinges. Therefore I suggest to add some labels.

Figure 2. This plot is quite dense. Do the pink and green lines represents values listed in Table 1? If so, why the pink lower ends for Groups and Clusters are lower than the respective Table 1 values? Moreover, do the pink vertical lines mark the the stellar masses values reported in Table 1 ? They do not seem so. Finally, I am not sure labels A and B are quoted through the text. I suggest you to add a sentence in the caption.

Line 102. I suggest to add a reference for the scaling relation connecting SM to BH mass.

Figure 3 and 4. It seems to me that it would be possible to merge these two plots into a single one. Moreover, I suggest to add units in the X and Y axis.

Author Response

 

I carefully read the manuscript “Why Jet Power and Star Formation Are Uncorrelated in Active Galaxies”. The authors investigate the possible correlation between jet power and star formation from a theoretical point of view. Their results are interesting and worth publishing after minor revision.

I include just a few minor comments that could be taken into consideration by the authors.

Author reply: Changes are made in green. Other colors are associated with changes connected to the other two referees.

INTRODUCTION

line 20. For the sake of completeness, I suggest to add a few lines explaining in a simple way the definition on positive and negative feedback.

Author reply: Added. Thank you.

SECTION 2

Figure 1. I find this figure probably missing a few labels indicating some elements which are mentioned in lines 50-60. Currently, it simply shows the tilt of the accretion disk, but does not displays any information on the environment onto which the jet impinges. Therefore I suggest to add some labels.

Author reply: Good point. We added a comment in the figure description about environment.

Figure 2. This plot is quite dense. Do the pink and green lines represents values listed in Table 1? If so, why the pink lower ends for Groups and Clusters are lower than the respective Table 1 values? Moreover, do the pink vertical lines mark the the stellar masses values reported in Table 1 ? They do not seem so. Finally, I am not sure labels A and B are quoted through the text. I suggest you to add a sentence in the caption.

Author reply: We added text to address this in the caption to Table 1. The stellar mass is a rough estimate of the mass for those environments in order to apply theory to obtain jet power. We also removed A and B points as they are not necessary for our study.

Line 102. I suggest to add a reference for the scaling relation connecting SM to BH mass.

Author reply: Done.

Figure 3 and 4. It seems to me that it would be possible to merge these two plots into a single one. Moreover, I suggest to add units in the X and Y axis.

Author reply: Merging them looks worse so we chose not to. We added units for SFR but not for jet power as it makes it look worse. Units listed in the caption for jet power.

Reviewer 2 Report

Comments and Suggestions for Authors

The paper "Why Jet Power and Star Formation Are Uncorrelated in Active Galaxies by D. Garofalo et al. is interesting and worth publishing. I have only minor comments, meant to enhace clarity of presentation. 

• Abstract: the second sentence is very long and should better be split in two.
• Introduction: for the reader not in the field a little text with a short recap of what positive and negative feedback is would be helpful. 
• throughout the text: yr. should be yr.
• Table 1 sems to be oddly formatted.
• Fig 3 is off center with respect to the text. I would suggest, for ease of readability, that you change the symbol according to colours, so as to make it legible for colorblind readers.
• Figure 4: I would suggest, for same ease of readability, that you change the line styles according to colours.

Finally, I suggest a thorough reading to see if long sentences can be split. It would make it easier to follow. 

Author Response

 

The paper "Why Jet Power and Star Formation Are Uncorrelated in Active Galaxies by D. Garofalo et al. is interesting and worth publishing. I have only minor comments, meant to enhace clarity of presentation. 

Abstract: the second sentence is very long and should better be split in two.

Author reply: Done. Also, changes addressing your issues are in blue. Other colors are due to changes for the other two referees.

Introduction: for the reader not in the field a little text with a short recap of what positive and negative feedback is would be helpful. 

Author reply: Referee 1 also made this comment. The text for this is green.

throughout the text: yr. should be yr.

Author reply: Isn’t the period ok?

Table 1 sems to be oddly formatted.

Author reply: Fixed.

Fig 3 is off center with respect to the text. I would suggest, for ease of readability, that you change the symbol according to colours, so as to make it legible for colorblind readers.

Author reply: Position and symbols fixed for Figure 3.

Figure 4: I would suggest, for same ease of readability, that you change the line styles according to colours.

Author reply: Fixed.

Finally, I suggest a thorough reading to see if long sentences can be split. It would make it easier to follow. 

Author reply: Done. Thanks.

Reviewer 3 Report

Comments and Suggestions for Authors

General comments:  I found this paper to be very informative and filled with original ideas that are backed up with data as well as theoretical arguments.  I have no major issues other than requesting minor modifications as described below.

1. Given how your paper is all about the relationship between jet power and star formation (albeit uncorrelated), I thought it might be useful if you could discuss in a sentence or two, or perhaps even a paragraph, the FRI/FRII dichotomy, particularly for the benefit of those not deeply immersed in this area.
2. Recently there has been a spate of papers and discoveries about black hole rotations, and even possibly asymmetries regarding those rotations. It would be useful if you could mention this and provide some references here.
3. Since you are discussing star formation, it might be a good idea to mention starburst galaxies, even if not very relevant here (or explain why it might not be relevant).
4. I am surprised that there is not much mention of VLBI observations. Did I miss something here?  Are they not available or not relevant?
5. You mention in the abstract that the jet power decreases in time, followed by a longer phase in which star formation is suppressed but coupled to jet power increasing with time etc. Please indicate whether this is ad hoc or based on evidence.
6. Line 44: please define excitation level and richness factor.
7. Figure 3: Excellent figure.  Very informative.

Author Response

 General comments:  I found this paper to be very informative and filled with original ideas that are backed up with data as well as theoretical arguments.  I have no major issues other than requesting minor modifications as described below.

1. Given how your paper is all about the relationship between jet power and star formation (albeit uncorrelated), I thought it might be useful if you could discuss in a sentence or two, or perhaps even a paragraph, the FRI/FRII dichotomy, particularly for the benefit of those not deeply immersed in this area.

Author reply: Done. Also, all changes associated with your comments are in red. Other colors are responses to the other two referees.

1. Recently there has been a spate of papers and discoveries about black hole rotations, and even possibly asymmetries regarding those rotations. It would be useful if you could mention this and provide some references here.

Author reply: Not sure which studies you are referring to.

1. Since you are discussing star formation, it might be a good idea to mention starburst galaxies, even if not very relevant here (or explain why it might not be relevant).

Author reply: Good point. We commented on this in the conclusions.

1. I am surprised that there is not much mention of VLBI observations. Did I miss something here?  Are they not available or not relevant?

Author reply: That is behind LOFAR which is mentioned.

1. You mention in the abstract that the jet power decreases in time, followed by a longer phase in which star formation is suppressed but coupled to jet power increasing with time etc. Please indicate whether this is ad hoc or based on evidence.

Author reply: This is based on a model wherein counter-rotation is the initial state. Once you allow for that initial condition, spin-down followed by spin-up are theoretically inevitable.

1. Line 44: please define excitation level and richness factor.

Author reply: Done.

1. Figure 3: Excellent figure.  Very informative.

Author reply: Thank you.