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Browse the New LIGO Catalog



Title: GWTC-2: Compact binary result observed by LIGO and Virgo in the first half of the third run

Authors: The scientific cooperation of LIGO and the cooperation of Virgo

Status: Available on arXiv

Back on September 14, 2015, the Laser Interferometer Gravitational Wave Observatory, or LIGO, detected the first gravitational waves from a pair of fused black holes. This opens up a new window to view the Universe through these ripples in spacetime. For the past 5 years, LIGO has been joined by the VIRGO gravitational wave detector and they have made a number of amazing discoveries, including the first-ever detection of many of the first passengers of gravitational waves with the GW1

70817, fusion first binary neutron star. LIGO-VIRGO Collaboration recently released a new category of gravitational wave detection from the first half of the third observational run, called O3a.

This new category includes 39 (!) New findings of compact object consolidation for six months from April 1, 2019 to October 1, 2019. There are so many other discoveries now that there are many. the case of two findings on the same day, so the detection identifier has been extended to include the hours, minutes and seconds of the findings. Some of the published findings, including GW190412 and GW190814, have been discussed in previous astrologers. Not only does this represent a huge increase in the number of gravitational wave detection, up from 11 in the previous category, it also contains some of the most interesting systems discovered to date.

Discover new seasonal merges

This figure shows that the number of gravitational wave findings from compact body fusion has quadrupled in the latest category compared to the previous one.  The effect volume of the investigated space also increased fourfold, showing how much more sensitive LIGO and VIRGO had become during this third run.
Figure 1: Total number of compact object fusion findings versus region where the time of binary neutron star volume (BNS VT), or effective space volume is investigated. Shaded areas show the volume observed during each run, which increases significantly for the O3a. The black line shows the total number of combinations detected as the survey volume increases, and the blue line shows the average number of detection for the O3a that matches the black line. Shaded blue areas show the 50% and 90% confidence intervals, or the uncertain areas, above the blue line. Figure 1 in the article.

In order to detect many of these new systems, both the LIGO detector and the VIRGO detector have undergone several upgrades to increase their sensitivity. This increase in sensitivity allows the detectors to find the fusion of gravitational waves in a much larger volume of space. This is shown in Figure 1, where the total number of discoveries has increased with the amount of space the detectors can search. The farthest finding in the category, GW190413_134308, comes from more than 5 giga-parsec, or Gpc, (more than 3 Billion a few light years away! That means not only can astronomers learn from the larger number of mergers, they can begin to see how this has evolved over time.

There are too many new findings in this category to discuss here, but there are a few highlights that have not been discussed before.

  • GW190521 This merger has the highest total mass (the sum of the masses of the two fused black holes) ever discovered at about 160 times the mass of the Sun (the mass of the Sun, or M), and the highest remaining mass (the mass of the black hole formed), about 150 M.
  • GW190425 – It is possible that a binary neutron star fusion with a component mass of 2.0 M and 1.4 million respectively, but neutron-black hole star fusion has not been ruled out.
  • GW190814 – Fused top layer fusion, with an object mass of 23 M and 2.6 million. It is not yet clear whether the smaller material is a black hole, or a large neutron star.
  • GW190426_152155 Although this candidate has the highest false alarm rate out of all findings in this category (1.4 per year, meaning there is a 1 chance of a similar false alarm occurring 1, 4 times per year), the volume of its ingredients, 5.7 million and 1.5 million, making it more likely neutron-black hole star fusion, assuming that it is a real astrophysics finding.

All of these systems are interesting on their right and Figure 2 shows the mass of the primary system (mfirst) and secondary (m2) object, in M, mass ratio (q), of objects, the effective spin (χeff), and distance (DL), in Gpc of each finding in this catalog.

This figure shows the posterior distributions for primary and secondary masses, mass ratios, effective spin and distance, of each gravitational wave fusion detected in this catalog.  The violin per parameter per detection shows the likelihood of that value increasing at probable measurements and narrowing when the value is less likely to occur.
Figure 2: Volume of primary (mfirst) and secondary (m2) object, in M, mass ratio, q, of objects, the effective rotation, χeffand distance, DL, in the Gpc of each finding in this category. The height of each point, or fiddle, of each measurement indicates the likelihood that it is the value being measured. So the wider the score, the more likely it is the actual value of each parameter. Figure 8 in the article.

Looking forward to the next categories

This portfolio has more than quadrupled the number of compact object fusions discovered by LIGO-VIRGO Collaboration. While this article presents a new list of findings from O3a, two other companion articles accompany this list. One seeks to quantify the number of expected fusions in the Universe of black hole binary and neutron star binaries using these new discoveries, and the other makes use of these new findings. to test general (very well organized) relativity.

There’s also a lot more to look forward to! This category is only the first half of the third observational run, the next half, from November 2019 to March 2020, is still being analyzed, so there are many more interesting findings on the way. And while that analysis continues, LIGO and Virgo are being upgraded once more, and are looking forward to being joined by a fourth detector, KAGRA, for their fourth observation. This will not only bring in more detection possibilities, but also allow us to more precisely pinpoint the places where these mergers are occurring in the sky, increasing the potential for interesting multi-passenger astronomy. taste!

Astrobite is edited by: Mitchell Cavanagh

Outstanding image credit: LIGO-Virgo / Northwestern U / Frank Elavsky and Aaron Geller

About Brent Shapiro-Albert

I am a fourth year graduate student at West Virginia University studying various aspects of pulsars. I am part of a NANOGrav collaboration that uses pulsar timing arrays to detect gravitational waves. In particular, I study how the interstellar medium affects the pulse emission. In addition to research, I enjoy reading, hiking and video games.


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