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posted by martyb on Friday June 02 2017, @12:44AM   Printer-friendly
from the catch-the-wave dept.

The Laser Interferometer Gravitational-Wave Observatory (LIGO) announced an observation of the merger of two black holes observed on 2017-01-04 having masses of approximately 31 and 19 times the mass of our sun (M) at a distance of approximately 880 Mpc (megaparsec) or approximately 2.8 billion light years.

From the full open access report (pdf) which was published in Physical Review Letters, by the American Physical Society (DOI: 10.1103/PhysRevLett.118.221101):

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10:11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70,000 years. The inferred component black hole masses are 31.2+8.4
−6.0
M and 19.4+5.3
−5.9
M (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χeff = −0.12+0.21
−0.30
. This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 880+450
−390
 Mpc corresponding to a redshift of z = 0.18+0.08
−0.07
. We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to mg ≤ 7.7 × 10−23 eV/c2. In all cases, we find that GW170104 is consistent with general relativity.

[...] The first observing run of the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) [1] identified two binary black hole coalescence signals with high statistical significance, GW150914 [2] and GW151226 [3], as well as a less significant candidate LVT151012 [4,5]. These discoveries ushered in a new era of observational astronomy, allowing us to investigate the astrophysics of binary black holes and test general relativity (GR) in ways that were previously inaccessible [6,7]. We now know that there is a population of binary black holes with component masses ≳25M⊙ [5,6], and that merger rates are high enough for us to expect more detections [5,8]. Advanced LIGO’s second observing run began on November 30, 2016. On January 4, 2017, a gravitational wave signal was detected with high statistical significance. Figure 1 shows a time-frequency representation of the data from the LIGO Hanford and Livingston detectors, with the signal GW170104 visible as the characteristic chirp of a binary coalescence.


B.P. Abbott et al. (Full author list appears at the end of the linked journal article).

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Once again, no visual confirmation. This time possibly due to technical issues with one detector:

The event candidate was not reported by the low-latency analysis pipelines because re-tuning the calibration of the LIGO Hanford detector is not yet complete after the holiday shutdown. This resulted in a delay of over 4 hours before the candidate could be fully examined. We are confident that this is a highly significant event candidate, but the calibration issue may be affecting the initial sky maps.

See also:
https://dcc.ligo.org/LIGO-P170104/public


Original Submission

 
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  • (Score: -1, Troll) by Anonymous Coward on Friday June 02 2017, @01:28AM (3 children)

    by Anonymous Coward on Friday June 02 2017, @01:28AM (#519144)

    Preferably a woman.

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  • (Score: -1, Troll) by Anonymous Coward on Friday June 02 2017, @01:30AM (1 child)

    by Anonymous Coward on Friday June 02 2017, @01:30AM (#519145)

    She was the larger of the masses.

    • (Score: -1, Troll) by Anonymous Coward on Friday June 02 2017, @01:34AM

      by Anonymous Coward on Friday June 02 2017, @01:34AM (#519150)

      The other mass was her dog.

  • (Score: -1, Troll) by Anonymous Coward on Friday June 02 2017, @01:32AM

    by Anonymous Coward on Friday June 02 2017, @01:32AM (#519147)

    Two holes of color, yes.