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The "Kilonova" associated with the neutron star binary merger GW170817

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Bikeman
Bikeman's picture
The "Kilonova" associated with the neutron star binary merger GW170817

Many here will have heard by now that on the 17th of Aug 2017, for the first time, the merger of two neutron stars was observed both in gravitational waves and in electromagnetic radiation. A wealth of papers covering this event can be found here: http://iopscience.iop.org/journal/2041-8205/page/Focus_on_GW170817.

I think from the perspective of amateurs, it is noteworthy that this particular event happened only ca 40Mpc away, which made the optical signal so bright that it was actually well within the reach of amateur equipment. For example, the telescope used for the DLT40 survey, for which you can see pre- and post-detection images in this paper:  http://iopscience.iop.org/article/10.3847/2041-8213/aa91c9/meta  (Fig 1 and 2), has a relatively modest 40cm aperture!  

In the past science runs of the gravitational wave detectors, alerts of detected events have only been shared in real-time with partners who had signed a Memorandum Of Understanding (MOU). But there can be little doubt that in the not too distant future, public alerts will be issued by gravitational wave observatories and then amateurs can also join the hunt for EM counterparts for GW signals. I hope the AAVSO will play a role in this quest.

Full disclosure: I'm a member of LIGO/VIRGO Collaboration but in no way representing them.

CS

HBE

daveh
daveh's picture
GW 170817

If you watch the NSF webcast of this morning, toward the end of the second segment (there were two panel discussions or segments to the briefing), the question came up regarding the role of amateurs in future GW detection. The feeling was that if there was reasonable alert time about a GW event that amateurs could indeed participate in the optical observation of the event. One of the main points of this briefing is that this neutron star merger was a "multi-messenger" event, i.e., multi-spectral event from gamma ray and x-ray to optical and radio, in addition the gravitational waves. The panel seemed to think that amateurs could indeed contribute to the optical part of future GW events if the "alert notices" could be sent out early enough for the amateurs to react. So, I guess the message is to stay tuned to see what will happen, but I viewed this as a potential opportunity in the future for amateurs.

David Benn
David Benn's picture
Neutrinos?

I have only read a couple of high level articles about this so far, and scanned Bikeman's first link.

Are neutrinos expected from an event such as this? Were any detected?

David

Bikeman
Bikeman's picture
No Neutrinos

Hi David!

Here's another list of publications for this event: http://public.virgo-gw.eu/gw170817_papers/

which includes a paper summarizing the results from a bunch of neutrino detectors, none of them found any that could be linked to the event.

https://dcc.ligo.org/public/0146/P1700344/006/GW170817_neutrinos.pdf

Form the abstract: "The non-detection is consistent with model predictions of short GRBs observed at a large off-axis angle".

Cheers

HB

 

David Benn
David Benn's picture
Neutrino papers

Thanks Bikeman.

David

Bikeman
Bikeman's picture
NGC 4993 archival data

Hi!

One more thing: It might be obvious, but still someone should spell it out: The last non-detection of the optical kilonova transient predates the detection by a rather long period of time: I think it was 2 days or 21 days, depending on which survey you feel you can rely on.

Now, if someone here would  (just by incredible luck!) have an image including NGC 4993 with sufficient depth and resolution to detect or rule out the transient in the three weeks before 2017/08/17, speak up :-) . By a quick check in VSX, I haven't found any well-observed variable star in the direct vicinity of NGC 4993, but hey, you never know...

Cheers

HB

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