From stiskraemer@yancey.gsfc.nasa.gov Tue Aug 6 12:05:18 2002 Date: Tue, 6 Aug 2002 11:59:31 -0400 From: stiskraemer@yancey.gsfc.nasa.gov To: yaqoob@skysrv.pha.jhu.edu, george@oberon.gsfc.nasa.gov, mckernan@pha.jhu.edu, turner@lucretia.gsfc.nasa.gov, GABEL@IACS.GSFC.NASA.GOV Subject: ref on Mrk 509 UV paper - minor stuff (mostly confusion + attitude) From: SMTP%"apj@phy.ohiou.edu",SMTP%"ApJ-MS56338@mss.uchicago.edu" 4-AUG-2002 16:53:13.84 To: stiskraemer@yancey.gsfc.nasa.gov CC: ApJ-MS56338@mss.uchicago.edu, apj@phy.ohiou.edu Subj: Your ApJ Submission MS# 56338 To: stiskraemer@yancey.gsfc.nasa.gov Subject: Your ApJ Submission MS# 56338 Cc: ApJ-MS56338@mss.uchicago.edu, apj@phy.ohiou.edu Sender: Web Peer Review System From: apj@phy.ohiou.edu Reply-to: apj@phy.ohiou.edu, ApJ-MS56338@mss.uchicago.edu Content-Length: 9619 Message-Id: <20020804205145Z214794-27229+105@mss.uchicago.edu> Date: Sun, 4 Aug 2002 15:51:32 -0500 Dr. Steven B. Kraemer Code 681 Building 21, Room G72 NASA/Goddard Space Flight Center Greenbelt, MD 20771 USA Dear Steve: Appended below is the referee's report on your submission to the ApJ entitled "The Kinematics and Physical Conditions of the Ionized Gas in Markarian 509. II. STIS Echelle Observations" ( MS# 56338). The referee has indicated that the results of this paper merit publication, but has noted a number of substantive matters that should be dealt with before the paper is accepted. I would be happy to consider for publication a revised version that addresses these points. When you resubmit the paper through the ApJ ftp site, please include a detailed cover letter containing the (mandatory) listing of the changes you have made to the text and your responses to the report. Processing of your revised manuscript will be expedited if you make your revisions to the manuscript latex file available for downloading from the ApJ Web Peer Review System (http://mss.uchicago.edu/ApJ/). This version includes your previous submission plus any modifications to latex commands necessary for smooth processing by the ApJ electronic system. If you have any questions, feel free to contact me. Best regards, Joe Joseph Shields, Scientific Editor The Astrophysical Journal Phone:740 593-0336 Fax:740 593-0433 apj@phy.ohiou.edu ************************* The Kraemer et al. paper "The Kinematics and Physical Conditions of the Ionized Gas in Markarian 509. II. STIS Echelle Observations." is worthy of the Astrophysical Journal after the comments below are addressed. This is a good companion paper with the one submitted by Yaqoob et al., and helps to establish that the X-ray and UV warm absorbers come from regions with distinctly different ionization state. The simultaneous UV-X-ray study is a good model of how future observations should be scheduled. General Comments: (1) Your column density measurements should be explained more carefully so the reader knows how they were done. (See 8 below) (2) Your model predictions for c III], H I and O VI might not match the observations because there is a range of ionization states (see 11 below). Your single zone model is inadequate. (3) The discussion of the possible warm absorber location/outflow geometry is a bit confusing. (See 14 below) Specific Comments: (4) Section 1., para 1: "Variability is suggestive of the proximity of the absorbers to the central active nucleus.." Add a sentence explaining what kind of variability is seen and how it implies 0.1pc size scale. Is it a recombination time argument? (5) Section 1., para 1: "Another indication of small radial distances is the low covering factors derived from the some UV absorption lines." Clarify which covering factor you mean, e.g. l.o.s. covering factor, not global covering factor. Also, since some of these sources are known to have extended, scattered emission, this weakens as an argument for small radial distance. (6) Section 1., para 1. "In fact there is often a wide range in ionization states in gas.. at the same radial velocities." You might add references to Seyfert galaxies such as NGC 4151, Mrk 3, and NGC 1068, which show strong correspondence between extended OUV and X-ray emission line nebulae and velocities. This is direct evidence for a large range of ionization and density at a single radius. It also suggests that the UV and X-ray absorbers may come from large radial distances in some cases, as you suggest in the Discussion. (7) Section 1., para 2. "..Pounds et al. constrained the inclination of the putative accretion disk to <30 degrees." Do you really believe that the inclination is well constrained by the fit shown in Pounds et al. 2001, Fig. 4a? Looks like a terrible fit to me. (8) Section 2.2, Column density measurements. OK, after re-reading this section, and reading the Hamann et al. ref, I see how your C_los and N_i were measured. I would suggest rearranging to make this more transparent. Put all of your measurement methods together in the first paragraph instead of splitting them between paragraphs 1 and 4. Be as explicit as possible, to help out the reader. Doesn't the Hamann method require the velocity width of each of the absn lines in the doublet to be resolved? Otherwise, the residual intensity in each line is a function of the Doppler parameter b as well as the ionic column density. Where does your assumption of a thermal profile get convolved into your column density measurements? Please let me know if I have this wrong. (9) Section 3.1, para 1: "For the models, we have assumed only thermal broadening, since the absorption line[sic] are quite narrow.." What temperatures are implied by your line widths? Are the component widths resolved by STIS? "..and widths greater than thermal are likely to be due to the super position of unresolved kinematic components." Granted, but how is this different from saying that you have resolved the lines, and they have measured b values of ~40 km/s? Operationally, what matters for the line depths is this b value. (10) Section 3.2, 1st sentence "The "best-fit" values of U and N_H for the models are given in Table 6." You never explained how you fit the model to the data. Did you fit the flux spectrum or the N_ion values measured using the Hamann method? If the former, I would like to see the fits superimposed on the data. If the latter, then it is foregone that the "..models match the observed N_NV and N_CIV values to well within the measurement errors." The ionization parameter is uniquely determined with two ions if you fix abundances at solar and fix the SED, no? Also, if you fit the model to the ionic columns, which columns did you use? All 4 of (H I(Ly-a), N V, C IV , and Si IV)? If you use all 4, then how can you "predict N_HI" (Last sentence of the same paragraph)? (11) Section 3.2, Discrepancies in observed and "predicted" C III, H I, O VI, etc. Your model underpredicts N_HI in your own data, and overpredicts O_VI in the Kriss et al. data, and underpredicts O VII in the Chandra data. Ignoring variability, this suggests to me that the NV, CIV, HI, O VI and OVII all come from clouds at different ionization parameter. No wonder your single ionization zone prediction doesn't work. Hence it has no predictive power, and comparing it with the Kriss et al. O VI line is a futile excercise. Yes, you can come up with other explanations why each line is under or over predicted, but in the end multiple ionization states is the simplest answer. Is it possible to fit all of the different ions with separate ionization parameters, then add them all up to get a net absorption profile for each line? This would be a very useful excercise, though I understand if you feel it is outside the scope of this paper. Also, I would suggest allowing for or discussing the possibility of non-solar abundances. (12) Section 3.2, para 4, "Our simulated OVI profile..provides a very good match" and "..a direct comparison of model and observed O VII column densities is not feasible, due to heavy saturation" Translation: a large range of high column densities can match the observed O VI (and H I Ly-alpha) profiles. (13) Section 3.3, para 2, 1st sentence: "Since, summed over the eight [model] kinematic components.... ..about 10% of the total [observed] O VII column.." Add indicated words to clarify sentence. (14) Section 4, 2nd sentence: "...the clustering of component velocities and the presence of redshifted gas...do not fit this general picture [radial outflow]." I disagree. The components have velocities from 200 to -400 km/s, which is consistent with outflow (mean blueshift). However, I do agree that the narrow widths and relatively low velocities are consistent with outflow in the NLR, not BLR. You go through a rather convoluted explanation of how you might get low velocities from a disk wind at BLR distances (2nd half of 1st paragragh); then end up concluding that this is unreasonable. This is confusing to the reader. Why spend so many words on a straw man, just to knock it down? It deserves one or 2 sentences at most. E.g. "The low velocities and line widths are inconsistent with a disk wind, barring a very contrived geometry." (15) Section 4., 3rd para: "..the X-ray and UV absorbers...are too neutral to be the hitchhiker gas proposed by Murray et al." Explain this to the reader. What is the proposed hitch-hiker gas, and quantify "too neutral" by comparing to the ionization parameter range given by Murray et al. (16) Section 5., point 2: "associated with one of[sic] more of" (17) Section 5., point 3: Rework to adress point 14 above. E.g. "it is not clear that [face on disk wind] could account for the large covering factors" In fact, no way could this account for it, unless the "disk wind" is nearly perpendicular to the disk. (18) References: Hamann et al. page # is wrong. Should be 80, not 78 (Note there are 2 Hamann et al. papers in the same Journal vol., and the second one is p. 87, but does not contain the detailed C_los argument. With some more attention to the details I mentioned above, this paper should be ready to go. Otherwise, I think it makes an important contribution to the knowledge of Sey 1 warm absorbers. *************************