Talk:ASASSN-15lh

A news item involving ASASSN-15lh was featured on Wikipedia's Main Page in the In the news section on 17 January 2016.

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Any need for any kind of protection for the article?[edit]

It's now in ITN. A few minutes ago over 2300 characters of totally unsourced Original Research by a user with no other edits was removed after surviving for 16 minutes (I was about to remove it, but another editor beat me to the punch). Does this suggest a need for some kind of protection for the article, and if so, what? Tlhslobus (talk) 17:07, 17 January 2016 (UTC)[reply]

That user is now permanently blocked. 98.67.179.99 (talk) 06:34, 18 January 2016 (UTC)[reply]

Simbad[edit]

There is a Simbad entry at http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%409630563&Name=SN%202015L&submit=submit Is there a good way to include that? Simbad claims a different galaxy as the host "Anon J220215-6139", linked at http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%409630551&Name=Anon%20J220215-6139&submit=submit but has nothing to say about it. Graeme Bartlett (talk) 20:08, 18 January 2016 (UTC)[reply]

I don't know astrophysics. Is this just a difference in nomenclature? Or does it indicate that the host galaxy is in dispute? Vesuvius Dogg (talk) 02:27, 19 January 2016 (UTC)[reply]

Almost all objects in astronomy have multiple names. The Palomar Sky Survey has existed since 1948 or something. Anything visible in that is in at least 1 if not 10 catalogs and you can search for all catalog entries within x distance of any position. Astronomers aren't stupid, those are likely just designations for the same galaxy in different catalogs. Sagittarian Milky Way (talk) 02:43, 19 January 2016 (UTC)[reply]

Distance[edit]

Sky & Telescope reckon the distance is 2.8 billion LY, not 3.8. [1] [2] The Yeti (talk) 22:56, 18 January 2016 (UTC)[reply]

I noticed that as well but suspect it's a typo, as other magazines and journalistic articles quote 3.8 billion and seem to draw from the aricle published in Science. But I'm unable to access the full text of the Science article to be certain. Vesuvius Dogg (talk) 23:51, 18 January 2016 (UTC)[reply]

@Vesuvius Dogg: The full text is available in the arXiv. They quote a distance of 1171 Mpc = 3817 Mly. 71.41.210.146 (talk) 00:41, 19 January 2016 (UTC)[reply]

That's 10x our Sun's lifetime energy output...[edit]

Foe (unit) mentions that the Sun's lifetime energy output will be about 1.2×10⁴⁴ J. This supernova's output of (1.1±0.2)×10⁴⁵ J is about 10 times that. Just interesting to note. 71.41.210.146 (talk) 00:47, 19 January 2016 (UTC)[reply]

Image[edit]

Does anyone know if NASA or some other orginasation has an image for this? It would really improve the article in my opinion. Will2022 (talk) 14:09, 19 January 2016 (UTC)[reply]

Energy vs. power[edit]

HI! "with an energy hundreds of billions times greater than the Sun" , doesn't sound educationally good. May be "with an power hundreds of billions times greater than the Sun" linked to https://en.wikipedia.org/wiki/Power_%28physics%29 is preferable. Or "emitting energy at rate of billions times greater than the Sun". — Preceding unsigned comment added by Algebraonly (talk • contribs) 20:04, 19 January 2016 (UTC)[reply]

Any reason its name sounds like "assassin"?[edit]

Were the scientists who named it trying to be cool or something? — Preceding unsigned comment added by 2602:252:D68:E80:DE5:94F1:8DB1:52A4 (talk) 21:06, 20 January 2016 (UTC)[reply]

Yes, exactly. It's common to want to make a pronounceable acronym out of a project name, so they started with "all-sky supernova", abbreviated "ASSN" and stuck in a few more letters to make a word. For other astronomical acronyms, see BICEP, AMANDA, WISE, VISTA, etc. 71.41.210.146 (talk) 11:51, 21 January 2016 (UTC)[reply]

Not to mention the fact that it sounds like ass in when pronounced. Sagittarian Milky Way (talk) 12:37, 21 January 2016 (UTC)[reply]

See also: WTF star and Wow! signal. emijrp (talk) 12:49, 21 January 2016 (UTC)[reply]

Radiation[edit]

"According to Krzysztof Stanek..." If it was in our galaxy, how far away would it have to be before we would be reasonably safe from the gamma/x-rays? I suspect many light years. AMCKen (talk) 22:37, 21 January 2016 (UTC)[reply]

A possible cause for Ordovician–Silurian extinction events is a gamma ray burst. According to that hyphotesis, "a hypernova within 6,000 light years of Earth, a ten-second burst would have stripped the Earth's atmosphere of half of its ozone almost immediately". emijrp (talk) 08:23, 22 January 2016 (UTC)[reply]

Peak Brightness?[edit]

Quoting from the Discovery section:

"Later on, other images were found to have been made of the supernova as early as May 8, 2015. At this stage the magnitude was 17.4. From May 8 the supernova brightened until it reached a peak brightness of magnitude 16.9 on June 5. By September the brightness had dropped to magnitude 18.2."

Something is wrong here I think. If the brightness in September was 18.2, how can the 16.9 be described as "peak brightness"? CBHA (talk) 18:08, 22 January 2016 (UTC)[reply]

Low is bright. Sagittarian Milky Way (talk) 18:25, 22 January 2016 (UTC)[reply]

Thank you. CBHA (talk) 18:40, 22 January 2016 (UTC)[reply]

For example, the Sun is -26, and Moon -12. emijrp (talk) 19:48, 22 January 2016 (UTC)[reply]

Flux vs energy[edit]

This edit by @Attilios: seems to correct an error in the cited source (NYT). Is there a published wp:RS that makes this comparision? If so, it should be cited. LeadSongDog come howl! 20:53, 26 January 2016 (UTC)[reply]

The Nature reference compared it to the Sun. Graeme Bartlett (talk) 00:42, 29 January 2016 (UTC)[reply]

So Nature called it "energy flux" or "power" in their comparison? The NYT said "energy", which is of course different.LeadSongDog come howl! 21:29, 4 February 2016 (UTC)[reply]

Not energy, but the brightness, which is flux. Graeme Bartlett (talk) 12:58, 5 February 2016 (UTC)[reply]

The Nature news piece used the word "brightness" to mean flux??? The horror! That's a perceptual metric, only very loosely connected to power, a.k.a. energy flux. To validly compare brightness of two sources one has to use the same (stated) wavelengths observed. The newspiece does, however, attribute the statement back to Dong's Science paper (ref 1 listed in the news piece). Dong, in turn, was describing a bolometric luminosity of 2.2E45 ergs/s (2.2E38 watt). The "brightness" misnomer seems to have originated in the Nature news piece. While Science used the word, it was not in such a comparison. LeadSongDog come howl! 20:29, 9 February 2016 (UTC)[reply]

Not a supernova[edit]

"The superluminous transient ASASSN-15lh as a tidal disruption event from a Kerr black hole"