By Elijah Bernstein-Cooper, March 31, 2015, 0 comments.

• Introduction will need to be expended and provide more detailed information but this can wait. However make sure you have enough information for your prelim research talk.

• Sentence starting with “transition has been identified as a threshold…” is not correct. The threshold was found observationally and HI-H2 transition is one possible explanation of this threshold, although still not fully confirmed and understood - that’s why we study our GMCs, otherwise all would be understood.

• Keep Section 2 for now, we can later trim it down. But please go through and provide more information that things are clear and can be followed. Also, be consistent how you call different things, e.g. you have different symbols for dust emissivity.

• I can not follow exactly what is being done from equations 1 and 2. Also, equations 1 and 3 are almost identical but you call quantities differently. It is also not clear to me that part about zero-level from LAB.

• Please check Draine book for calling various variables. E.g. I am used to seeing “total-to-selective extinction ratio” for Rv (not selective extinction curve?). This is very important, plus great as prelim prep.

• Does Fig 1 show your final Av image? As you derive this using two Planck images, how do transition pixels look like? Do you need to do something to ensure smooth transitions? Or are there any sharp transitions present (which can affect other calculations)?

• Fig. 1 does show the final model $A_V$ image. There are indeed some sharp transitions. Especially in the western side of Taurus. See below.

+ You can also find the data here /d/bip3/ezbc/taurus/data/av/taurus_av_planck_5arcmin.fits

• Please state in relevant sections RMS uncertainty of your Av image, 2mass Av image, HI data. This is important. Also mention any limitations Juni’s maps have, e.g. limited to <25mag.

• Section 3: This section has a lot of good material but I can not follow what exactly is being done - sorry. Please go through to ensure logical progression.

• In 3.2.1 say boundaries are set by eye. Was any specific strategy used? In 3.1 at the start, say what corresponds to data and what is the model.

• In 3.2.2 you say you use 2nd moment - is this correct? 1st moment corresponds to mean velocity, often it is calculated by applying intensity weighting. 2nd moment corresponds to velocity dispersion.

• I’ve gone through up to Section 4. I see that section 5 starts abruptly with modeling but will need some basic explanation of the models and various parameters. Also, this should have first a section showing Perseus application and discussion of how results compare with Lee et al.

• You also want to have some discussion of estimated delta_V and DGR parameters somewhere.