Neutrino bursts are observed before the visible light of supernovas, most famously SN 1987A. Astronomers likewise expect gravitational waves.

Gravitational waves are supposed to travel at exactly the speed of light (right?), but neutrinos are merely relativistic. Would looking at the delay between the GW and neutrino waveforms help estimate neutrino mass?

  • $\begingroup$ In the usual language of particle physics the neutrinos would be described as "ultra-relativistic". We're talking Lorentz factors of $10^6$ and up, so it will take quite a distant source and good consistent model of the supernova dynamics to sort out the travel time issues. $\endgroup$ – dmckee --- ex-moderator kitten Feb 21 '16 at 16:09
  • $\begingroup$ @dmckee What part of our current understanding of SN dynamics would need further refinement in order to calculate this? $\endgroup$ – Jimmy G. Mar 14 '16 at 15:40

The dynamical process of a stargoing supernova is not instantaneous. Thus the neutrino burst and the initial brightening need not be simultaneous

An accumulation of observations, along with diigent stellar collapse modelling is required for the development of a comprehensive theory.

Gravitational observations should add to this process.

  • $\begingroup$ Core collapse is about as instantaneous as it gets. Light does not escape for some time, but neutrinos do make a sharp peak — according to Wikipedia, less than 13 sec for SN 1987A. So part of this question is, might the delay be greater than the peak duration for an even which is close enough to observe? (The light from SN 1987A was trapped by refraction for over 2 hours. I don't suppose that signal is useful here.) $\endgroup$ – Blackbody Blacklight Feb 21 '16 at 14:16
  • $\begingroup$ A few hours is not instantaneous; this is a race between three very fast signals, two of which travel at c, but may suffer delays, and the third which travels at o.9999... c, and travels right through most roadblocks. So who's first and last off the blocks will change who arrives first. $\endgroup$ – Peter Diehr Feb 22 '16 at 2:29
  • $\begingroup$ Core collapse occurs on the order of seconds. The delay of hours is due to propagation of light through the stellar envelope, after the collapse of the core. Hence, light seems to be irrelevant to this question. Are you suggesting that neutrinos may be delayed? Why would that be? $\endgroup$ – Blackbody Blacklight Feb 22 '16 at 8:54
  • 2
    $\begingroup$ I understand that light doesn't get emitted from the SN because it has to "battle" its way to the top; however, I don't see how this is relevant because neither neutrinos nor gravitational waves would have this problem. Correct me if i am wrong, but the neutrino burst and gravitational waves would happen virtually instantaneously, making not only the visible light, but all light throughout the entire EMS, irrelevant. I am sure I am oversimplifying something, but the basic premise is that the two variables with which we are interested, are not set on a "time-delay" like light is. $\endgroup$ – Jimmy G. Mar 14 '16 at 15:46

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