Pentcho Valev
2016-07-18 06:59:57 UTC
Initially neutron star gravitational waves were regarded as "far more common candidates" than black hole gravitational waves:
http://www.lastwordonnothing.com/2016/06/16/getting-from-wow-to-yawn/
"What surprised the LIGO collaboration instead was the nature of what they’d detected. Of the various gravitational-wave-producers that LIGO might observe—the kind that disturb space-time to such an extent that LIGO could register the aftershock—the collision of binary black holes was perhaps the least likely. Supernovae, neutron stars, colliding neutron stars: These were what the LIGO collaboration foresaw as far more common candidates. And now LIGO has detected a second pair of colliding black holes."
http://theadvocate.com/news/15893528-126/after-breakthrough-gravitational-wave-finding-ligo-scientists-look-ahead-to-new-discoveries
"Before the Sept. 14 detection, LIGO scientists had focused their calculations on the mergers of neutron stars, not black holes. That’s because neutron stars — the dense remnants of collapsed stars — had been observed already through other means, like electromagnetic radiation, and were, thus, more predictable, said Joseph Giaime, head of the LIGO Livingston Observatory and a professor of physics and astronomy at LSU."
Judging from the text above, the detection of neutron star gravitational waves is much easier. Even if the signal is weak and inconclusive at first, comparison with INTEGRAL's data might lead to a straightforward conclusion in the end:
http://www.esa.int/Our_Activities/Space_Science/Integral_sets_limits_on_gamma_rays_from_merging_black_holes
"Models predict that the merging of two stellar-mass black holes would not produce light at any wavelength, but if one or two neutron stars were involved in the process, then a characteristic signature should be observable across the electromagnetic spectrum. Another possible source of gravitational waves would be an asymmetric supernova explosion, also known to emit light over a range of wavelengths. [...] Integral is sensitive to transient sources of high-energy emission over the whole sky, and thus a team of scientists searched through its data, seeking signs of a sudden burst of hard X-rays or gamma rays that might have been recorded at the same time as the gravitational waves were detected. "We searched through all the available Integral data, but did not find any indication of high-energy emission associated with the LIGO detection," says Volodymyr Savchenko of the François Arago Centre in Paris, France. Volodymyr is the lead author of a paper reporting the results, published today in Astrophysical Journal Letters. [...] Subsequent analysis of the LIGO data has shown that the gravitational waves were produced by a pair of coalescing black holes, each with a mass roughly 30 times that of our Sun, located about 1.3 billion light years away. Scientists do not expect to see any significant emission of light at any wavelength from such events, and thus Integral's null detection is consistent with this scenario. [...] The only exception was the Gamma-Ray Burst Monitor on NASA's Fermi Gamma-Ray Space Telescope, which observed what appears to be a sudden burst of gamma rays about 0.4 seconds after the gravitational waves were detected. The burst lasted about one second and came from a region of the sky that overlaps with the strip identified by LIGO. This detection sparked a bounty of theoretical investigations, proposing possible scenarios in which two merging black holes of stellar mass could indeed have released gamma rays along with the gravitational waves. However, if this gamma-ray flare had had a cosmic origin, either linked to the LIGO gravitational wave source or to any other astrophysical phenomenon in the Universe, it should have been detected by Integral as well. The absence of any such detection by both instruments on Integral suggests that the measurement from Fermi could be unrelated to the gravitational wave detection."
So why are you silent about neutron star gravitational waves, LIGO folks? Unless you break the silence, the only conceivable explanation is this:
Faking black hole gravitational waves remains unpunished and is awarded with millions of dollars while faking neutron star gravitational waves can be exposed by alternative observations and is therefore too dangerous.
Pentcho Valev
http://www.lastwordonnothing.com/2016/06/16/getting-from-wow-to-yawn/
"What surprised the LIGO collaboration instead was the nature of what they’d detected. Of the various gravitational-wave-producers that LIGO might observe—the kind that disturb space-time to such an extent that LIGO could register the aftershock—the collision of binary black holes was perhaps the least likely. Supernovae, neutron stars, colliding neutron stars: These were what the LIGO collaboration foresaw as far more common candidates. And now LIGO has detected a second pair of colliding black holes."
http://theadvocate.com/news/15893528-126/after-breakthrough-gravitational-wave-finding-ligo-scientists-look-ahead-to-new-discoveries
"Before the Sept. 14 detection, LIGO scientists had focused their calculations on the mergers of neutron stars, not black holes. That’s because neutron stars — the dense remnants of collapsed stars — had been observed already through other means, like electromagnetic radiation, and were, thus, more predictable, said Joseph Giaime, head of the LIGO Livingston Observatory and a professor of physics and astronomy at LSU."
Judging from the text above, the detection of neutron star gravitational waves is much easier. Even if the signal is weak and inconclusive at first, comparison with INTEGRAL's data might lead to a straightforward conclusion in the end:
http://www.esa.int/Our_Activities/Space_Science/Integral_sets_limits_on_gamma_rays_from_merging_black_holes
"Models predict that the merging of two stellar-mass black holes would not produce light at any wavelength, but if one or two neutron stars were involved in the process, then a characteristic signature should be observable across the electromagnetic spectrum. Another possible source of gravitational waves would be an asymmetric supernova explosion, also known to emit light over a range of wavelengths. [...] Integral is sensitive to transient sources of high-energy emission over the whole sky, and thus a team of scientists searched through its data, seeking signs of a sudden burst of hard X-rays or gamma rays that might have been recorded at the same time as the gravitational waves were detected. "We searched through all the available Integral data, but did not find any indication of high-energy emission associated with the LIGO detection," says Volodymyr Savchenko of the François Arago Centre in Paris, France. Volodymyr is the lead author of a paper reporting the results, published today in Astrophysical Journal Letters. [...] Subsequent analysis of the LIGO data has shown that the gravitational waves were produced by a pair of coalescing black holes, each with a mass roughly 30 times that of our Sun, located about 1.3 billion light years away. Scientists do not expect to see any significant emission of light at any wavelength from such events, and thus Integral's null detection is consistent with this scenario. [...] The only exception was the Gamma-Ray Burst Monitor on NASA's Fermi Gamma-Ray Space Telescope, which observed what appears to be a sudden burst of gamma rays about 0.4 seconds after the gravitational waves were detected. The burst lasted about one second and came from a region of the sky that overlaps with the strip identified by LIGO. This detection sparked a bounty of theoretical investigations, proposing possible scenarios in which two merging black holes of stellar mass could indeed have released gamma rays along with the gravitational waves. However, if this gamma-ray flare had had a cosmic origin, either linked to the LIGO gravitational wave source or to any other astrophysical phenomenon in the Universe, it should have been detected by Integral as well. The absence of any such detection by both instruments on Integral suggests that the measurement from Fermi could be unrelated to the gravitational wave detection."
So why are you silent about neutron star gravitational waves, LIGO folks? Unless you break the silence, the only conceivable explanation is this:
Faking black hole gravitational waves remains unpunished and is awarded with millions of dollars while faking neutron star gravitational waves can be exposed by alternative observations and is therefore too dangerous.
Pentcho Valev