New Binary Gravitational Wave event

[antoniseb]

After 11 days or so with no reported events, GraceDB is showing a new event (S190602aq) estimated at 700 megaparsecs. This is one of the closest BBH events observed so far.

[StupendousMan]

It's somewhat frustrating that binary black hole events are unlikely to produce any (or much) electromagnetic radiation. It means that we can't really learn anything other than the data LIGO and VIRGO provide.

Rats.

[antoniseb]

I agree, it is frustrating. I think of these early ALIGO and VIRGO detections as the beginning of this. I imagine that future space-based observations with future equipment will provide resolutions that will help rule out large groups of models and confirm a small subset, or perhaps even force the creation of new models. For the moment, we are collecting knowledge about how many of these events there are, and how to see them more clearly.

[antoniseb]

Another new one: S190630ag - this one has very little specificity about where it happened, perhaps because VIRGO has been out of service getting an update. This is the first new report in 4 weeks.

[antoniseb]

And another one: S190701ah - This one has the most precise indication for where in the sky it happened of all so far. There must be something new helping with this triangulation. This might be the beginning of a new improved level observation.

[antoniseb]

And another one: S190706ai - Binary Black Hole. This one is about 4760MPc away (a new distance record)

[antoniseb]

Virgo still isn't back online, so the recent ones have been weak on location, but the distance and other details are good. S190720a - Binary black hole about 940 MPc from here.

[George]

It's somewhat frustrating that binary black hole events are unlikely to produce any (or much) electromagnetic radiation.

Isn't too early to say there's no sausage making going on when uber masses collide? Doesn't the inverse square law limit what EM we might see when distances are many billions of trillions of miles?

[antoniseb]

Isn't too early to say there's no sausage making going on when uber masses collide? Doesn't the inverse square law limit what EM we might see when distances are many billions of trillions of miles?

I don't think we're saying that in theory there are no photons, but rather that there are few enough that we don't yet detect these events above the background noise, and so have nothing else to measure with current instruments.

[George]

I don't think we're saying that in theory there are no photons, but rather that there are few enough that we don't yet detect these events above the background noise, and so have nothing else to measure with current instruments.

I had the impression that the theory did not expect EM emission, but it will likely take something much closer to see it, if they exist for BBHs.

If a merger were to produce a matching solar luminosity, at 700 Mparsecs it would have a mag. of 44; 29 mag. if in Andromeda.

[StupendousMan]

Standard theory states that a black hole merging with a black hole can produce no photons. However, if there is gas around one or both of the black holes, then the crazy accelerations of the gas during the merger _can_ create photons.

So, the question becomes "How much gas is circling one or both black holes when they merge?" I don't know how much gas must be present to produce as much electromagnetic radiation as a standard supernova (around 10^51 ergs = 10^44 Joules); does anyone have rough estimates?

[George]

Standard theory states that a black hole merging with a black hole can produce no photons.

Thanks, that's what I thought the theory claimed. But, as a novice admittedly, there's just something odd about an event unimaginably violent in energy production -- 3 solar masses for the first LIGO observation -- that must stretch, if not tare, the space-time fabric without exciting virtual particles, or something, out of their deep caves (Foamville). And then there's that 10¹²⁰ energy factor that seems to have turned-up missing, but if it's in the caves, what better time for some of it to spill out?

Also, if entropy (per Hawking) correlates with the surface area of the EH, and the EH size changes during the merger, wouldn't the change of entropy alone bring credibility for some production of EM and heat? Why would something so violent generate only something so serene as a GW?

[I tried to be subtle with my hyperbole, of course. ]

However, if there is gas around one or both of the black holes, then the crazy accelerations of the gas during the merger _can_ create photons.

So, the question becomes "How much gas is circling one or both black holes when they merge?" I don't know how much gas must be present to produce as much electromagnetic radiation as a standard supernova (around 10^51 ergs = 10^44 Joules); does anyone have rough estimates?

Yes, and this is expected, and found I think, when neutron stars are involved with a merger.

[antoniseb]

S190727h & S190728q both are likely binary black hole events, without very specific locations because they are too distant for VIRGO to detect them.

[Roger E. Moore]

Is it easier to detect such events when they are at a great distance, or are these just random examples of the distances at which such events happen to occur at the present moment? In other words, would a BH merger with Sag A* produce a notable blip? Apologizing for simplistic question but am sleepy and confused at the moment.

[George]

I think it’s wave amplitude and distance that give signal quality. And since the amplitude is linear with distance the mass sizes are less demanding.

[antoniseb]

Is it easier to detect such events when they are at a great distance, or are these just random examples of the distances at which such events happen to occur at the present moment? In other words, would a BH merger with Sag A* produce a notable blip? Apologizing for simplistic question but am sleepy and confused at the moment.

I don't think we would detect a black hole merging with Sgr A*, it would take many minutes for the small black hole to make its last orbit around the big one. Our detectors are tuned to orbits of a smallish number of milliseconds. As to distance, I think if you assume as a first approximation that the rate of such mergers has been roughly constant for the last 8 billion years, that the number we see goes up as the cube, out to the distance we can't detect them. VIRGO goes out to about 600 Megaparsecs, ALIGO in Louisiana goes out to maybe 4000 megaparsecs, depending on noise. In twenty years or so we should have several detectors that can detect such events all the way to the dark age. We could be seeing several events per minute at that time.

[chornedsnorkack]

The distribution of events should include frequent "ordinary" events, occasional "apparently loud" events which are intrinsically ordinary but happen to be nearby, and intrinsically quiet events which are only detectable because they happen to be nearby.

Any examples of the last two types?

[George]

I don't think we would detect a black hole merging with Sgr A*, it would take many minutes for the small black hole to make its last orbit around the big one. Our detectors are tuned to orbits of a smallish number of milliseconds. As to distance, I think if you assume as a first approximation that the rate of such mergers has been roughly constant for the last 8 billion years, that the number we see goes up as the cube, out to the distance we can't detect them. VIRGO goes out to about 600 Megaparsecs, ALIGO in Louisiana goes out to maybe 4000 megaparsecs, depending on noise. In twenty years or so we should have several detectors that can detect such events all the way to the dark age. We could be seeing several events per minute at that time.

Now that I see I missed the question entirely, your point seems very logical. But it's a great question since there is a lot happening with an infalling BH into a SMBH. The gravity gradient may be far gentler at the EH, but that is still a speed of light velocity at that point. Wouldn't something big happen, but what?

[antoniseb]

There were two events seen earlier today, about 21 minutes apart, both were binary black hole events, both in the same area of the sky. https://gracedb.ligo.org/superevents/S190828j/view/ & https://gracedb.ligo.org/superevents/S190828l/view/

[antoniseb]

NewScientist is reporting that the two Aug 28th events might have been one event gravitationally lensed.

[slang]

NewScientist is reporting that the two Aug 28th events might have been one event gravitationally lensed.

Now that would be an interesting twist!

[antoniseb]

Another strange GW event https://gracedb.ligo.org/superevents/S190910h/view/ S190910h. This one is probably a binary neutron star, but there is almost no indicator as to where in the sky it happened. I guess this means only one detector saw it.

[antoniseb]

Today's GW event is probably a Neutron Star merging with a Black Hole about a billion light years from here. It might be a terrestrial event. The signal was too weak to be detected by VIRGO.

[antoniseb]

Today's GW Event is a mass gap event. meaning that it seems to have at least one member of the merger as an object more massive than the most massive neutron star, and less massive than the least massive known black hole. I'm not sure how to find further details. You can't see them directly from this website. Does anyone know a source for details of the estimated masses of new events?

[antoniseb]

Today there have been two events reported so far (about an hour apart), but one might be terrestrial. The other one is another mass gap event.

[antoniseb]

There had been about 5 weeks of no events reported. Perhaps the detectors were being updated or maintained. There have been two events recently on Nov 5 and Nov 9.

[antoniseb]

A new confirmed BBH event S191129u has been reported. I didn't notice anything especially remarkable about this event compared to the other amazing events from LIGO and VIRGO, but this is the first event in 20 days that has not been rejected. There were six events in that time which were reported to GraceDB, and then rejected (prior to that only 8 events rejected over 6 months). Also, there were several in October and early November which were not reported right away, but do appear in the lists now. Perhaps we were going through a testing period, or perhaps a change in personnel.

[antoniseb]

A few more events have been reported recently. The most recent was S191205ah which was a black hole-neutron star merger perhaps 400 MPc away. I don't know if a GRB was observed that corresponds with this.

[StupendousMan]

It appears there was no electromagnetic counterpart:

https://gcn.gsfc.nasa.gov/other/S191205ah.gcn3

[antoniseb]

Thanks! I had just been seeing the GraceDB information. This GCN report answers a lot of my questions.