Science & Technology
Now optical telescopes - including the Hubble Space Telescope - are scrambling to point at the source of the possible wave: an elliptical galaxy hundreds of millions of light years away.
Gravitational waves are markers of the most violent events in our universe, generated when dense objects such as black holes or neutron stars crash together with tremendous energy. Two experiments - LIGO in the US and VIRGO in Europe - set out to detect minuscule changes in the path of laser beams caused by passing gravitational waves.
LIGO has discovered three gravitational wave sources to date, all of them colliding black holes. The two observatories have been coordinating data collection since November, increasing their sensitivity. That collaboration may be about to pay off.
Neutron stars
Over the weekend, astronomer J. Craig Wheeler of the University of Texas at Austin launched speculation over a potential new LIGO detection by tweeting: "New LIGO. Source with optical counterpart. Blow your sox off!"
By optical counterpart, he probably means that astronomers could observe light emitted by the gravitational wave source. This suggests the source is neutron stars as, unlike black holes, they can be seen in visible wavelengths. LIGO researchers have long-anticipated this possibility, setting up partnerships with optical observatories to rapidly follow-up on potential signals prior to formally announcing a discovery.
LIGO spokesperson David Shoemaker dodged confirming or denying the rumours, saying only "A very exciting O2 Observing run is drawing to a close August 25. We look forward to posting a top-level update at that time."
Speculation is focused on NGC 4993, a galaxy about 130 million light years away in the Hydra constellation. Within it, a pair of neutron stars are entwined in a deadly dance. While astronomers are staying silent on whether they are engaged in optical follow-ups to a potential gravitational wave detection, last night the Hubble Space Telescope turned its focus to a binary neutron star merger within the galaxy. A publicly available image of this merger was later deleted.
If LIGO and VIRGO really have picked up the gravitational waves of colliding neutron stars, it might explain why collaborator Andy Howell mused earlier in the week, "Tonight is one of those nights where watching the astronomical observations roll in is better than any story any human has ever told."
Reader Comments
1. GW170817 [Link]
2. GW150914 [Link]
3. Problems with NGC 4993/AT2017gfo/GRB170817A/GW170817 association and subsequent inadequacies in time and frequency domain models for a kilonova transient viewed off-axis with an enduring (and possibly oscillating/recurring) afterglow: [Link]
4. GRB150101B as evidence for the validity of GRB170817A: [Link]
Lags between observer-dependent group arrival for GW are also readily identified as those produced by the unusually structured and energetic inter-detector line-of-sight thunderstorms (which are absent in literature on the topic, including those papers focusing on Schumann resonant mode excitation for stochastic GW background signal discrimination):
5. lag reproduction from thunderstorm-LIGO stations line-of-sight spatial relations [Link]
6. pulse-coherent CG lightning surrounding all GW events: [Link]
7. LIGO magnetometers still do not consider the Z-component in time evolution of local magnetic field at intervals < 1 minute, and arm-mounted on-site LIGO magnetometers were left off from September 12 2015 to November 2015; it is these multiple magnetometer sensor data streams by which LIGO will ultimately be tested prior to aLISA (expected to be launched by 2034): [Link]
There are excess correlations between LIGO event parameters and multiscaled-periodic/quasiperiodic physical systems that remain unexplained:
8. joint orbital variation affecting sunspot cycle and sunspot/solar radio flux Fourier analysis, with LIGO event timing and energy/distance parameters embedded into orbital time series [Link]
9. LIGO event parameter correlations and systematic error [Link]
10. Superposed epoch analyses (daily bins, 5-minute bins) from multiple complete Solar, magnetospheric, and ionospheric transient and anomaly datasets, with embedded LIGO daily events [Link]
Comment: See also: