Talk:Megamaser

Megamaser has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.

Article milestones
Date	Process	Result
March 4, 2011	Good article nominee	Listed

A fact from this article appeared on Wikipedia's Main Page in the "Did you know?" column on February 6, 2011.

The text of the entry was: Did you know ... that hydroxyl megamasers were used to make the first detection of Zeeman splitting in a galaxy other than the Milky Way?

GA Review

This review is transcluded from Talk:Megamaser/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Jezhotwells (talk) 18:54, 4 March 2011 (UTC)[reply]

I shall be reviewing this article against the Good Article criteria, following its nomination for Good Article status.

Disambiguations: Four found and fixed.[1] Jezhotwells (talk) 19:02, 4 March 2011 (UTC)[reply]

Linkrot: None found. Jezhotwells (talk) 19:02, 4 March 2011 (UTC)[reply]

Checking against GA criteria

GA review (see here for criteria)

It is reasonably well written.
a (prose): b (MoS for lead, layout, word choice, fiction, and lists):
I find taht the article is reasonably well written and accords sufficiently with the MoS and project guidelines.
It is factually accurate and verifiable.
a (references): b (citations to reliable sources): c (OR):
I assume good faith for off-line sources, article is sufficiently referenced. In passing, I am puzzled by the appearance of edit tags following the journal cites, but this is not of concern in this review.
It is broad in its coverage.
a (major aspects): b (focused):
the artcile covers the subject sufficiently, without too much detail.
It follows the neutral point of view policy.
Fair representation without bias:
NPOV
It is stable.
No edit wars, etc.:
Stable
It is illustrated by images, where possible and appropriate.
a (images are tagged and non-free images have fair use rationales): b (appropriate use with suitable captions):
Licensed, tagged and captioned.
Overall:
Pass/Fail:
I find that the article meets the GA criteria. I enjoyed reading it and have learnt a lot about this branch of astronomy. Listing as GA. Congratulations. Jezhotwells (talk) 19:17, 4 March 2011 (UTC)[reply]

association with Seyfert 2, not Seyfert 1, implies AGN accretion tori are wide & flat ?

Inexpertly, Seyfert 2 galaxies are Seyfert 1 galaxies, but viewed "edge on" instead of "face on". However, megamasers are not observed, from "face on" Seyfert 1 galaxies. Since masing amplification derives from the optical depth, along the sightline to earth, of excited "pumped" molecules, perhaps the accretion tori of Seyfert galaxies are flat and wide, resembling a large washer, for a bolt or screw? Low flat wide accretion tori would have considerably more optical depth "edge on" than "face on", since the sightlines through the masing medium would be allot longer. So, perhaps the association of megamasers only with "edge on" Seyferts suggests something of the structure of their SMBH accretion disks? Moreover, the SMBH in "edge on" Seyferts resides directly behind (half of) the masing medium, and so might be a source of the "triggering" radio emissions? 66.235.38.214 (talk) 04:34, 26 December 2012 (UTC)[reply]

According to info from this article, the mean-free path between collisions, for OH molecules, in megamasing media, is λ = 1/nσ ~ 1AU. And, so, the mean-free time between collisions is τ = λ/C_S ~ 10yr. According to Advanced Astrophysics by Neb Duric, the rotational & vibrational excitation modes responsible for masing-frequency emissions are meta-stable, having lifetimes of ~10Myr. Ipso facto, OH molecules in dense warm megamasing media could collide millions of times, and become collisionally excited, before ever spontaneously naturally de-exciting. So collisional excitation may be an easy explanation, for the "pumping" process — millions of collisional encounters, with other particles, perpetually "pump" energy into rotational & vibrational excited states, with nearly no spontaneous decays occurring, so "setting" the entire masing medium into an excited stated, "waiting" to be triggered, at appropriate radio-to-microwave frequencies? If so, then perhaps a professional could improve the Wikipedia article, with appropriate references & citations? 66.235.38.214 (talk) 05:16, 26 December 2012 (UTC)[reply]