Talk:NGC 4993

This article was nominated for deletion on 31 August 2017. The result of the discussion was keep.

Image

Can we obtain an actual image of the galaxy? I'm not sure that an image of a generic elliptical galaxy is appropriate in the infobox. Tayste (edits) 02:28, 13 September 2017 (UTC)[reply]

I agree. An image from DSS2 is being used by other articles: https://telescoper.files.wordpress.com/2017/08/ngc4993.png .

The caption from https://in-the-sky.org/data/object.php?id=NGC4993 is "Red-band image from the Second Digitized Sky Survey (DSS2), measuring 10 arcminutes across." Five minutes of searching doesn't give me a clue what the copyright status of this image is. Larry Doolittle (talk) 05:25, 22 September 2017 (UTC)[reply]

Done - also agree - updated to the following image => File:GalaxyNGC4993-DsoBrowser-NgcIcProject-2017.jpg - copyright & related should be ok, but *entirely* ok with me to rv/rm/ce/upd image & related description/permissions as needed of course - in any case - Enjoy! :) Drbogdan (talk) 15:04, 22 September 2017 (UTC)[reply]

Clarification about the latest news

There were some irrelevant additions added and then removed from the article, and there are some misleading statements in the history. I think it is worth clarifying, if only that no one jumps the gun at the next announcement of a non-detection. There are lots of things LIGO is not detecting, and most of it is irrelevant to this article.

The new LIGO paper is about the non-detection of the gravitational radiation from an off-kilter rotating neutron star, and the prospects of detecting such in future runs. That's "star", singular, not "stars", binary, so of course nothing about a collision. The expected signal is a continuous tone with frequency up to twice the star's rotation frequency. Such a signal would be very weak—the only way to see it with LIGO is that it repeats itself for months and years—and no signal from outside the Milky Way is expected. The O1 non-detection is not surprising.

If you want to see the relevant papers, the link [1] lists all the relevant LSC publications. Look for the CW label (Continuous Wave). At the moment, there are three CW papers at the bottom. 129.68.81.217 (talk) 14:44, 14 September 2017 (UTC)[reply]

Stay tuned ...

Quoting from [2]:

In fact, neutron-star collisions had been expected by many to be the source of the first detected gravitational waves. Noting that another announcement by the LIGO team has been scheduled for October 16, Weiss said that such collisions “do happen”.
— Photonics World, "Nobel winner Weiss hints at neutron-star result"

I'll remark the article links, in the sidebar, to the nature.com "Rumours swell" article. And don't forget to click on the MIT video for more hinting.

To the editor who claimed he had inside knowledge against the rumors, it looks like they played a sneaky little ploy with some GW170814 rumors of their own. Time will tell. 129.68.81.67 (talk) 16:39, 4 October 2017 (UTC)[reply]

More on Weiss's hinting about the forthcoming announcement [3]:

Now, the big question is, how often does that happen, that two neutron stars smash into each other? Well, I won't say any more.
— Calla Cofield, space.com, "Gravitational-Wave Announcement Coming on Oct. 16: What Could It Be?"

According to the article, Weiss refused to clarify, nor did any other LIGO participant. 129.68.81.132 (talk) 16:33, 8 October 2017 (UTC)[reply]

The announcement will presumably be made on the first day of this IAU Symposium [4]: "Gravitational Wave Astrophysics: Early Results from GW Searches and Electromagnetic Counterparts" 129.68.81.132 (talk) 17:02, 8 October 2017 (UTC) [5][reply]

One more link, reporting on a talk of Robert Byer, lead developer of LIGO's lasers, at a recent conference on lasers [6]:

“I’m willing to admit,” Byer said, concluding his talk, “that what they will announce will be one of the most important events in the history of astrophysics.”
— Stewart Wills, "Under the Hood with LIGO’s Lasers"

That is almost certainly a reference to the birth of multi-messenger astronomy itself, and not merely a different kind of GW signal. 129.68.81.132 (talk) 17:39, 8 October 2017 (UTC)[reply]

Announcement details

The big announcements start at 10 AM EDT on Monday, and they will be livestreamed [7]. The two panels are being hosted by the Director and the Assistant Director of NSF. Representatives from SEVENTY observatories are to be there. Speakers include one from FERMI (gamma-ray) and one from Las Cumbres (continuous world-wide optical monitoring). Obviously, it's an incredibly big deal. 129.68.81.112 (talk) 19:05, 15 October 2017 (UTC)[reply]