by alter-ego » Fri Jun 17, 2016 5:07 am
Craig Willford wrote:
The description talks of red shift. Spectrum shifts are detected in relation to known expected, non-shifted emission or absorption lines. Gravity waves don't have those. What red shift was detected and how?
That's right, the redshift is not directly measured.
Instead GW strain amplitude (the measured quantity) is used to calculate the distance, which in turn using the standard cosmological model yields the redshift, z. [ Strain ≡ ΔL/L ∝ r
s/r where r
s = Schwarzschild radius, and r = luminosity distance ]
If there was normal matter in close proximity to the black holes as they spiraled down, I would think the massive gravity waves might so compress and distend the matter that they would display absorbed energy with bright, high frequency photons that might be detected if a telescope were looking in the right direction at the right time, even at a distance of 1.4 billion light years.
Assuming a mass could survive long enough during coalescence to reach unity strain (unity strain ~ Schwarzschild radius), most likely a vast amount of heat will be generated rather than a lot of high energy photons. Heat and destruction would depend on the strain amplitude and duration (i.e. total merger mass) and details of the unlucky mass. A rocky body would certainly have a lot of debris while a gas cloud would get hot and maybe not break up. Simply put, I expect the mass-to-energy conversion ratio from GW strain oscillations would be exceedingly small compared to a supernova-like event (e.g. Type Ia) which is required for visibility over 1.4 billion ly.
[quote="Craig Willford"]
The description talks of red shift. Spectrum shifts are detected in relation to known expected, non-shifted emission or absorption lines. Gravity waves don't have those. What red shift was detected and how?[/quote]
That's right, the redshift is not directly measured.
Instead GW strain amplitude (the measured quantity) is used to calculate the distance, which in turn using the standard cosmological model yields the redshift, z. [ Strain ≡ ΔL/L ∝ r[sub]s[/sub]/r where r[sub]s[/sub] = Schwarzschild radius, and r = luminosity distance ]
[quote]If there was normal matter in close proximity to the black holes as they spiraled down, I would think the massive gravity waves might so compress and distend the matter that they would display absorbed energy with bright, high frequency photons that might be detected if a telescope were looking in the right direction at the right time, even at a distance of 1.4 billion light years.
[/quote]
Assuming a mass could survive long enough during coalescence to reach unity strain (unity strain ~ Schwarzschild radius), most likely a vast amount of heat will be generated rather than a lot of high energy photons. Heat and destruction would depend on the strain amplitude and duration (i.e. total merger mass) and details of the unlucky mass. A rocky body would certainly have a lot of debris while a gas cloud would get hot and maybe not break up. Simply put, I expect the mass-to-energy conversion ratio from GW strain oscillations would be exceedingly small compared to a supernova-like event (e.g. Type Ia) which is required for visibility over 1.4 billion ly.