GW190521 as a Merger of Proca Stars: A Potential New Vector Boson of 8.7×10−13eVABSTRACT
Advanced LIGO-Virgo have reported a short gravitational-wave signal (GW190521) interpreted as a quasicircular merger of black holes, one at least populating the pair-instability supernova gap, that formed a remnant black hole of Mf∼142M at a luminosity distance of dL∼5.3Gpc. With barely visible pre-merger emission, however, GW190521 merits further investigation of the pre-merger dynamics and even of the very nature of the colliding objects. We show that GW190521 is consistent with numerically simulated signals from head-on collisions of two (equal mass and spin) horizonless vector boson stars (aka Proca stars), forming a final black hole with Mf=231+13−17M, located at a distance of dL=571+348−181Mpc. This provides the first demonstration of close degeneracy between these two theoretical models, for a real gravitational-wave event. The favored mass for the ultralight vector boson constituent of the Proca stars is μV=8.72+0.73−0.82×10−13 eV. Confirmation of the Proca star interpretation, which we find statistically slightly preferred, would provide the first evidence for a long sought dark matter particle.
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.081101
Is there more info on Proca Stars? I found all links pointed to this article or others where they just say it's a Bose-Einstein boson star.
Is there more info on Proca Stars? I found all links pointed to this article or others where they just say it's a Bose-Einstein boson star.
Doing a search on the term returns numerous papers unrelated to this one.
See the link below as an example.
https://arxiv.org/abs/1508.05395
Is there more info on Proca Stars? I found all links pointed to this article or others where they just say it's a Bose-Einstein boson star.
Well yes, that is what it is. Proca stars are a vector boson (spin 1) version of hypothesised scalar boson (spin 0) stars, usually called SBS. They are self-gravitating condensates of a new theoretical low-mass boson. They can be incredibly dense, but as long as they are stable they won't collapse into a singularity; unless of course they collide, disrupting the condensate. Part of the interest in the idea is that in some ways they would mimic black holes, which may be why we see what we think are black holes in the LIGO observations but with masses that don't seem possible with the collapse of ordinary matter. If Proca stars exist and indeed are made up of a new low-mass boson they are a dark matter candidate.
It's a relatively new and esoteric subject so there is very little accessibly written on it so far. Pretty much everything discussing them is an academic paper. This is probably the best layman explanation of the situation,
https://spaceaustralia.com/index.php/feature/black-holes-or-boson-stars-mystery-gw190521Edit: Also,
https://briankoberlein.com/blog/proca-stars/https://www.sciencealert.com/there-could-be-transparent-stars-made-of-bosons-masquerading-as-black-holes(Though it refers to the scalar boson version.)
I've got that. But you can hypothesize about a stellar object composed only of up quarks, or whatever. But how would they have formed? Why would they be formed of just that? Etc. Explaining a middle mass black hole can be explained by a massive companion that it slowly consumed. I don't understand how you can say that a a stellar object made up only of a single boson is a better explanation than a black hole that ate a companion or more.
GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing RunThe third Gravitational-wave Transient Catalog (GWTC-3) describes signals detected with Advanced LIGO and Advanced Virgo up to the end of their third observing run. Updating the previous GWTC-2.1, we present candidate gravitational waves from compact binary coalescences during the second half of the third observing run (O3b) between 1 November 2019, 15:00 UTC and 27 March 2020, 17:00 UTC. There are 35 compact binary coalescence candidates identified by at least one of our search algorithms with a probability of astrophysical origin pastro>0.5. Of these, 18 were previously reported as low-latency public alerts, and 17 are reported here for the first time. Based upon estimates for the component masses, our O3b candidates with pastro>0.5 are consistent with gravitational-wave signals from binary black holes or neutron star-black hole binaries, and we identify none from binary neutron stars. However, from the gravitational-wave data alone, we are not able to measure matter effects that distinguish whether the binary components are neutron stars or black holes. The range of inferred component masses is similar to that found with previous catalogs, but the O3b candidates include the first confident observations of neutron star-black hole binaries. Including the 35 candidates from O3b in addition to those from GWTC-2.1, GWTC-3 contains 90 candidates found by our analysis with pastro>0.5 across the first three observing runs. These observations of compact binary coalescences present an unprecedented view of the properties of black holes and neutron stars.
https://arxiv.org/abs/2111.03606Source:
https://phys.org/news/2021-11-scientists-tsunami-gravitational.html
After being offline for three years for upgrades LIGO and associated facilities begin the O4 observing run from the 25/05.
Details below.
On Wednesday, the LIGO-Virgo-KAGRA (LVK) collaboration began a new observing run with upgraded instruments, new and even more accurate signal models, and more advanced data analysis methods. The LVK collaboration consists of scientists across the globe who use a network of observatories — LIGO in the United States, Virgo in Europe, and KAGRA in Japan — to search for gravitational waves, or ripples in space-time, generated by colliding black holes and other extreme cosmic events.
This observing run, known as O4, promises to take gravitational-wave astronomy to the next level. Beginning on May 24 and lasting 20 months, including up to two months of commissioning breaks, O4 will be the most sensitive search yet for gravitational waves. LIGO will resume operations May 24, while Virgo will join later in the year. KAGRA will join for one month, beginning May 24, rejoining later in the run after some upgrades.
https://news.mit.edu/2023/gravitational-wave-detectors-start-next-observing-run-0525