"On 8:41 AM EDT August 17, 2017, LIGO detected a new gravitational wave source, dubbed GW170817 to mark its discovery date. Just two seconds later NASA's Fermi satellite detected a weak pulse of gamma rays from the same location of the sky." https://www.cfa.harvard.edu/news/2017-30

"Just two seconds later" and "the same location of the sky" implies that gravitational waves and optical signals traveled hand in hand: same gravitationally deflected path, same speed, same Shapiro delay, equally absorbed (stopped) by cosmic matter. Realistic? Obvious fraud?

Pentcho Valev