Catch-up post

Thanksgiving holiday: email exchange with Laura Chajet about modeling inhomogeneous absorption; she has found an error in the original formulation of these models which may require redoing quite a bit of published work. Also ported a lot of Google Wave reviews of published astro papers to Zenbe Shareflow.

Monday: read revised bits of Jesse Rogerson's Master's thesis. Read 1st draft of a followup C IV / X-ray paper by Gordon Richards' student Nic Kruczek, and drafted email to them. Read Steinhardt & Elvis' comment on the paper Alireza Rafiee & I put on astro-ph earlier this month. They have some good suggestions for clarification, some mistakes, and one good point for us to consider.

Tuesday: sent a few more comments to Jesse. Spent lots of time fixing proofs for MNRAS paper on FBQS J1408+3054. I'm paying the price for being lazy and not using natbib. But I've now figured out how to use natbib for MNRAS (basically, use mn.bst and not mn2e.bst).

Daily Update; BAL EW vs. time for transverse motion

Finished & sent note to Fred Hamann about arXiv:1008.3728. Finished one last task for grant report.

An idea inspired by Guido Risaliti's recent OSU colloquium: if you have BAL region "clouds" which are rotating in the same sense as the accretion disk, and if the accretion disk follows the Hubeny et al. models where the rotationally approaching half of the disk is brighter than the receding half, you might be able to verify those models by looking at BAL EWs vs. time. (Assuming also that the transverse motion of the BAL is dominated by rotation.) As a BAL cloud first moves in front of the disk, the absorption EW should increase rapidly, as the part of the disk being covered is the bright, approaching half. In other words, for an absorber gradually covering the whole continuum source, a depth halfway to maximum absorption should be reached in less than half the time to maximum absorption (equivalently, at half the time to maximum absorption, the depth will be more than halfway to maximum). For a BAL cloud moving out of our LOS to the continuum source, from complete covering to zero covering, the recovery to continuum will happen faster in the 1st half of the uncovering timescale than in the 2nd half.

Daily Update

As alluded to in the previous post, today I read Morabito et al. 1011.4327 and sent a quick note to the authors. Also I read Hamann et al. 1008.3728 (variability in a high-velocity quasar NAL system) and started writing a quick note to Fred. Also followed up on an email to Hans-Walter Rix about quasar variability. Also got email from Chris Churchill with MgII EW numbers for a lensed quasar for Jesse; still waiting for similar numbers on another system from George Djorgovski. Also filled in a progress report (including some budgeting) for my Ontario Early Researcher Award.

Average density in BAL X-ray absorbers

Astronomy over the weekend included fixing a factor of 2 numerical error in my most recent paper (which fortunately hasn't gone to press yet). A question from Joe Shields led me to think about density and column density limits in the outflow in FBQS J1408+3054. By crude analogy to a similar FeLoBAL with published high-resolution spectra and X-ray data (J0300+0048), the Fe II column density lower limit is uninteresting. But if the total column density in this object is Compton thick with N_H >= (10^24 cm^-2)/Z where Z is the metallicity relative to solar, then the average density of the X-ray absorber must be >~(10^4 cm^-3)/fZ where f is its filling factor along the line of sight. For example, if the X-ray absorber (which is likely not identical to the UV absorber) extends from the BH out to 1/10th the distance of the UV BAL gas, then its density has to be >~(10^5 cm^-3)/Z. If the X-ray absorber extends farther from the BH than the UV absorber, then f>1 in the above and the density can be lower. But too much of the X-ray absorber exterior to the UV absorber will cause Compton scattering of the quasar's UV continuum and remove it from sight.

Update: Morabito et al. 1011.4327 today reinforce the above by pointing out that in FeLoBALs studied to date, f<<1 because the X-ray absorber must be interior to the UV continuum emitting region or else it would Thomson scatter the UV continuum out of our line of sight. For the 1.4E8 Msun BHs in that paper, R_Sch = 4E13 cm and 20R_Sch=8E14 cm. For a column N_H=(1E25 cm^-2)/Z located interior to that radius, the average density is 1E25/8E14 = (1.25 x 10^10 cm^-3)/Z.

Gamma-ray NLS1s, BAL spectra

A check of the HST archive reveals that none of the five narrow-line Seyfert 1 galaxies (NLS1s) detected to date in gamma-rays (all at redshifts < 1) have HST spectra. These AGN are very likely to be within a few degrees of face-on to their accretion disks, and we can see broad emission lines from them, so we have a rare opportunity to study broad line profiles at a known inclination angle. Sounds like an HST proposal to me.

Other recent activities have included:
a Skype conversation with my student Laura Chajet;
simple reductions of MDM spectroscopy of a variable BAL quasar to see if it its variability is ongoing (it's not, unfortunately);
a bit of digging around in papers on Hanny's Voorwerp or related subjects;
and realizing there's a factor of two error in my latest first-author paper (d'oh!) ...fortunately, once the error is corrected the result is more interesting rather than less, and the paper's still at the proofs stage and so the error can be corrected before it is printed. That won't endear me to the MNRAS staff, but I think I'll request to be sent a paper to referee as a way of making amends.

PHL 1811 analogs, Thesis, Postdoc

For the PHL 1811 analog paper: replaced a file; analyzed an HST spectrum; reconsidered a redshift; added a sentence on testing a speculative explanation.

Read and commented on Jiang & Goodman's arXiv:1011.3541 paper on star formation in quasar accretion disks (well written, but a modest step forward, not a great leap).

Rogerson Master's Thesis delivered to supervising committee; Skype conversation with Jesse mapping out refinements to the analysis to tackle next.

Budgeted for postdoc and other research expenses over the next few years, and wrote email answering queries about my offer to my first-choice postdoc applicant.

Quasars: Some Answers, More Questions

Here is a PDF version of the talk I gave yesterday at Ohio University. If you want to see the simulation by Kurosawa & Proga in action, click on the density (zoom) movie here. If you want to see the animation of the disappearing FeLoBAL trough, click here.

Weekend: PHL 1811 analogs, Mg II absorption

Dug up some old information on PHL 1811 analogs for the forthcoming paper, and wrote a few more sentences about them. Also continued to review drafts of Jesse Rogerson's Master's Thesis, plus did some investigation of MgII data in other quasar asterisms. Began adopting old colloquium into new version for talk at Ohio University tomorrow.

Cross-matched SDSS quasar catalogs

I've been toiling off and on for a few days on cross-matching various SDSS quasar catalogs. Thought I had it all sewn up Tuesday night, but realized Wednesday morning that I'd been using the UNIX 'uniq' command incorrectly. After fixing that I thought I was finished Thursday morning; then I remembered I wanted to cross-match another catalog, and in so doing I identified some discrepancies it took me the rest of the day to track down and fix.

But today the cross-matched catalogs are available online for anyone to use. I only ask that you read the Readme file! More catalogs will probably be cross-matched in the future.

Other activities:
* have been making comments on drafts of Jesse Rogerson's Master's Thesis
* Guido Risaliti visited this week so I attended the colloquium he gave, had dinner with him and Brad Peterson, and chatted with him a bit about AGN science
* usual daily Astro Coffee and Friday Journal Club meetings
* also read "Carrots and Sticks: Unlock the Power of Incentives to Get Things Done" by Ian Ayres, which isn't astronomy but which I plan to apply to astronomy (among other things) as soon as I digest it a bit further

Weekend Update (PHL 1811 Analogs, sub-Eddington Boundary)

Science over the weekend and through today so far has focused on thinking some more about PHL 1811 analogs (intrinsically X-ray weak quasars), about which Niel Brandt, his grad student Jianfeng Wu and I (and collaborators) are preparing a paper.

I also prepared some materials in support of a colleague's NSF proposal.

Lastly, my former grad student Ali Rafiee had a paper on astro-ph (it's still astro-ph to me, not arXiv) today showing that the reported sub-Eddington boundary is not seen in our analysis of quasar black hole masses vs. luminosities. Reaction here at Ohio State (and by email from another member of the community) has been positive; Occam's Razor is on our side!

Week On, Week Off

I was on vacation from last Thursday afternoon through Tuesday afternoon; only work-related item done was to send off a reference letter for my former grad student Ali Rafiee. Wednesday through Friday of this week was spent catching up on email, advising my student Jesse Rogerson on his Master's thesis, and reading through the job applications and reference letters for the postdoctoral fellowship I've advertised to work with me at York starting next year. I narrowed it down to a shortlist of six people, including my first choice and the runner-up, and made an offer to my first choice today. It's likely the decision won't be finalized until early next year, after the results of prestigious fellowship competitions are announced, but I'm pleased with the shortlisted applicants.