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"Kilonova" Observed Using Gravitational Waves, Sparking Era of "Multimessenger Astrophysics"

posted by takyon on Tuesday October 17 2017, @04:42AM   Printer-friendly
from the medium-bang dept.

Scientists Witness Huge Cosmic Crash, Find Origins of Gold

Phoenix666 writes:

It started in a galaxy called NGC 4993, seen from Earth in the Hydra constellation. Two neutron stars, collapsed cores of stars so dense that a teaspoon of their matter would weigh 1 billion tons, danced ever faster and closer together until they collided, said Carnegie Institution astronomer Maria Drout.

The crash, called a kilonova, generated a fierce burst of gamma rays and a gravitational wave, a faint ripple in the fabric of space and time, first theorized by Albert Einstein.

The signal arrived on Earth on Aug. 17 after traveling 130 million light-years. [...] The colliding stars spewed bright blue, super-hot debris that was dense and unstable. Some of it coalesced into heavy elements, like gold, platinum and uranium. Scientists had suspected neutron star collisions had enough power to create heavier elements, but weren't certain until they witnessed it. "We see the gold being formed," said Syracuse's Brown.

So the ring on your finger is actually the skeletal remains of neutron stars.

Observatories Across the World Announce Groundbreaking New Gravitational Wave Discovery

AnonTechie writes:

Today, physicists and astronomers around the world are announcing a whole new kind of gravitational wave signal at a National Science Foundation press conference in Washington, DC. But it's not just gravitational waves. That August day, x-ray telescopes, visible light, radio telescopes, and gamma-ray telescopes all spotted a flash, one consistent with a pair of neutron stars swirling together, colliding and coalescing into a black hole. The observation, called a "kilonova," simultaneously answered questions like "where did the heavy metal in our Universe come from" and "what causes some of the gamma-ray bursts scientists have observed since the 60s." It also posed new ones.

[...] All in all, the discovery marks an important milestone in gravitational wave astronomy and proof that LIGO and Virgo do more than spot colliding black holes. At present, the detectors are all receiving sensitivity upgrades. When they come back online, they may see other sources like some supernovae or maybe even a chorus of background gravitational waves from the most distant stellar collisions.

https://gizmodo.com/observatories-across-the-world-announce-groundbreaking-1819500578

[Also Covered By]:

Papers:

Optical emission from a kilonova following a gravitational-wave-detected neutron-star merger (open, DOI: 10.1038/nature24291) (DX)

Spectroscopic identification of r-process nucleosynthesis in a double neutron-star merger (open, DOI: 10.1038/nature24298) (DX)

A gravitational-wave standard siren measurement of the Hubble constant (open, DOI: 10.1038/nature24471) (DX)

The X-ray counterpart to the gravitational-wave event GW170817 (open, DOI: 10.1038/nature24290) (DX)

A kilonova as the electromagnetic counterpart to a gravitational-wave source (open, DOI: 10.1038/nature24303) (DX)

Origin of the heavy elements in binary neutron-star mergers from a gravitational-wave event (open, DOI: 10.1038/nature24453) (DX)

Multi-messenger Observations of a Binary Neutron Star Merger (open, DOI: 10.3847/2041-8213/aa91c9) (DX)

Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A (open, DOI: 10.3847/2041-8213/aa920c) (DX)

An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A (open, DOI: 10.3847/2041-8213/aa8f41) (DX)

INTEGRAL Detection of the First Prompt Gamma-Ray Signal Coincident with the Gravitational-wave Event GW170817 (open, DOI: 10.3847/2041-8213/aa8f94) (DX)

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. I. Discovery of the Optical Counterpart Using the Dark Energy Camera (open, DOI: 10.3847/2041-8213/aa9059) (DX)

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. II. UV, Optical, and Near-infrared Light Curves and Comparison to Kilonova Models (open, DOI: 10.3847/2041-8213/aa8fc7) (DX)

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta (open, DOI: 10.3847/2041-8213/aa9029) (DX)

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South (open, DOI: 10.3847/2041-8213/aa905c) (DX)

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. V. Rising X-Ray Emission from an Off-axis Jet (open, DOI: 10.3847/2041-8213/aa9057) (DX)

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VI. Radio Constraints on a Relativistic Jet and Predictions for Late-time Emission from the Kilonova Ejecta (open, DOI: 10.3847/2041-8213/aa905d) (DX)

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VII. Properties of the Host Galaxy and Constraints on the Merger Timescale (open, DOI: 10.3847/2041-8213/aa9055) (DX)

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VIII. A Comparison to Cosmological Short-duration Gamma-Ray Bursts (open, DOI: 10.3847/2041-8213/aa9018) (DX)

The Discovery of the Electromagnetic Counterpart of GW170817: Kilonova AT 2017gfo/DLT17ck (open, DOI: 10.3847/2041-8213/aa8edf) (DX)

A Deep Chandra X-Ray Study of Neutron Star Coalescence GW170817 (open, DOI: 10.3847/2041-8213/aa8ede) (DX)

The Unprecedented Properties of the First Electromagnetic Counterpart to a Gravitational-wave Source (open, DOI: 10.3847/2041-8213/aa905e) (DX)

The Emergence of a Lanthanide-rich Kilonova Following the Merger of Two Neutron Stars (open, DOI: 10.3847/2041-8213/aa90b6) (DX)

Observations of the First Electromagnetic Counterpart to a Gravitational-wave Source by the TOROS Collaboration (open, DOI: 10.3847/2041-8213/aa9060) (DX)

The Old Host-galaxy Environment of SSS17a, the First Electromagnetic Counterpart to a Gravitational-wave Source (open, DOI: 10.3847/2041-8213/aa9116) (DX)

The Distance to NGC 4993: The Host Galaxy of the Gravitational-wave Event GW170817 (open, DOI: 10.3847/2041-8213/aa9110) (DX)

The Rapid Reddening and Featureless Optical Spectra of the Optical Counterpart of GW170817, AT 2017gfo, during the First Four Days (open, DOI: 10.3847/2041-8213/aa9111) (DX)

Optical Follow-up of Gravitational-wave Events with Las Cumbres Observatory (open, DOI: 10.3847/2041-8213/aa910f) (DX)

A Neutron Star Binary Merger Model for GW170817/GRB 170817A/SSS17a (open, DOI: 10.3847/2041-8213/aa91b3) (DX)

Previously: European Southern Observatory to Announce "Unprecedented Discovery" on Monday

Original Submission #1  Original Submission #2  Original Submission #3 

 
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  • (Score: 1, Informative) by Anonymous Coward on Tuesday October 17 2017, @01:14PM

    by Anonymous Coward on Tuesday October 17 2017, @01:14PM (#583444)

    On 2017 August 17 12:41:06 UTC the Fermi Gamma-ray Burst Monitor (GBM; Meegan et al. 2009) onboard flight software triggered on, classified, and localized a GRB. A Gamma-ray Coordinates Network (GCN) Notice (Fermi-GBM 2017) was issued at 12:41:20 UTC announcing the detection of the GRB, which was later designated GRB 170817A (von Kienlin et al. 2017). Approximately 6 minutes later, a gravitational-wave candidate (later designated GW170817) was registered in low latency (Cannon et al. 2012; Messick et al. 2017) based on a single-detector analysis of the Laser Interferometer Gravitational-wave Observatory (LIGO) Hanford data.

    The signal was consistent with a BNS coalescence with merger time, tc, 12:41:04 UTC, less than before GRB 170817A. A GCN Notice was issued at 13:08:16 UTC. Single-detector gravitational-wave triggers had never been disseminated before in low latency. Given the temporal coincidence with the Fermi-GBM GRB, however, a GCN Circular was issued at 13:21:42 UTC (LIGO Scientific Collaboration & Virgo Collaboration et al. 2017a) reporting that a highly significant candidate event consistent with a BNS coalescence was associated with the time of the GRB959

    http://iopscience.iop.org/article/10.3847/2041-8213/aa91c9 [iop.org]

    I see they rendered the background model invalid (again), so a significant deviation from it doesn't mean much. Honestly, from this I don't know what to think. I thought the multi-message signal would be convincing, I really did. At first it sounded good: Observe a GW then predict what other signals should show up. If they do show up when and where it was predicted, great looks like you've got it. But somehow once again they have given me an uncomfortable feeling.

    The gamma ray burst (GRB) was detected first, then they went back into the LIGO data and found a candidate to match up to it. Apparently this candidate would not have been approved without having a coincident GRB (it would have been marked as background), since it was only triggered in one GW detector. This is not the process I expected.

    The GW data should be used entirely on its own to tell the EM and GRB people where to look. It shouldn't have gone GRB -> GW + EM, not if we are trying to verify the instrument is functioning properly. The treatment of the GW signal should have been independent of the others.

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