Event Horizon Telescope ready to image black hole

[eeergo]

200 scientists from many worldwide institutions synchronizing and organizing work from the different millimeter-wave observing telescopes.

Highlighting how cooperation between countries was the only way to get these images.

EDIT: Adding a diagram of the interferometry telescope subtended throughout the Western hemisphere by the EHT to perform this observation.

[eeergo]

Any news about the imaging of sagittarius a?

Just confirmed SgA* analysis is ongoing and are confident they will soon be able to release images. Probably hindered by a much more dirty background.

[eeergo]

For context, this is a wide-field image from Hubble of M87/Virgo A and its relativistic jet.

[Star One]

Any news about the imaging of sagittarius a?

Just confirmed SgA* analysis is ongoing and are confident they will soon be able to release images. Probably hindered by a much more dirty background.

Thank you.  Makes sense as our BH is tiny compared to this and has vast amounts of dust around.

[eeergo]

They imaged Messier-87* first because it is 1000 times larger than Sgr-A* but also 1000 times further away, so the relative size is approximately the same. This wasn't well constrained at all, so it was kind of a lucky shot. However, Sgr-A* is rotating much faster, so this makes it much more difficult to get a sharp image of it. Also mentioned how the accretion plasma is quite "optically" (in radio, obviously) thin in M87*, so they can see the shadow - which is quite an interesting result just by itself.

[Star One]

They imaged Messier-87* first because it is 1000 times larger than Sgr-A* but also 1000 times further away, so the relative size is approximately the same. This wasn't well constrained at all, so it was kind of a lucky shot. However, Sgr-A* is rotating much faster, so this makes it much more difficult to get a sharp image of it. Also mentioned how the accretion plasma is quite "optically" (in radio, obviously) thin in M87*, so they can see the shadow - which is quite an interesting result just by itself.

It’s interesting that our BH is more rapidly rotating is that a function of its smaller size/mass?

[eeergo]

Low frequencies allow you to see the jets, but not the accretion disk.

High frequencies such as the millimeter waves they studied allows you to get detailed images, but light is much more distorted and it gets difficult to identify in an undistorted way where the jets are coming from. They hypothesize, although it's still not proven, the jets originate in the Doppler-brightened spot on the bottom of the disk in the image.

The accretion disk is very thick and we're looking at it almost face-on, although the bottom is Doppler-brightened because of a slight angle towards us.

Excluding wormhole models, boson stars. Simplest explanation is consistent with Einstenian BH everywhere they've looked at.

[eeergo]

They imaged Messier-87* first because it is 1000 times larger than Sgr-A* but also 1000 times further away, so the relative size is approximately the same. This wasn't well constrained at all, so it was kind of a lucky shot. However, Sgr-A* is rotating much faster, so this makes it much more difficult to get a sharp image of it. Also mentioned how the accretion plasma is quite "optically" (in radio, obviously) thin in M87*, so they can see the shadow - which is quite an interesting result just by itself.

It’s interesting that our BH is more rapidly rotating is that a function of its smaller size/mass?

IIRC it's just a matter of angular momentum conservation (i.e. how the forming bodies were rotating/translating with respect to each other).

[eeergo]

Rotation rate is very difficult to measure with precision because of the relativistic light-bending. Think the spinning exists, and is pointing away from us (its vector) because of the energetic jets that are visible.

For now, they have a "sense" of rotation only: its clockwise direction.

Polarization of the light is already inherent to the released data (but still not fully analyzed). It will shed light on M87*'s magnetic fields, which will also give more clues as to how it's rotating.

[Star One]

Rotation rate is very difficult to measure with precision because of the relativistic light-bending. Think the spinning exists, and is pointing away from us (its vector) because of the energetic jets that are visible.

For now, they have a "sense" of rotation only: its clockwise direction.

Polarization of the light is already inherent to the released data (but still not fully analyzed). It will shed light on M87*'s magnetic fields, which will also give more clues as to how it's rotating.

By the way thanks for covering this news conference on here.

[eeergo]

Rotation rate is very difficult to measure with precision because of the relativistic light-bending. Think the spinning exists, and is pointing away from us (its vector) because of the energetic jets that are visible.

For now, they have a "sense" of rotation only: its clockwise direction.

Polarization of the light is already inherent to the released data (but still not fully analyzed). It will shed light on M87*'s magnetic fields, which will also give more clues as to how it's rotating.

By the way thanks for covering this news conference on here.

My pleasure! My head hurts because I've been watching this (and trying to understand it well) while attending an important work meeting that's been going on for 2h now... thankfully I didn't have to contribute much - or so I think, because I haven't been so attentive during the last hour   but it was definitely worth it!

Papers: https://iopscience.iop.org/journal/2041-8205

[Star One]

4K image.

https://www.nsf.gov/news/special_reports/blackholes/downloads/A-Consensus.jpg

Useful video.

[Star One]

Just a reminder about this documentary showing in the U.K. tonight.

Documentary to be shown on BBC 4 in the U.K. on the 10th April.

How to See a Black Hole: The Universe’s Greatest Mystery

Documentary following researchers as they try to take the first-ever picture of a black hole. They must travel the globe to build a revolutionary telescope that spans planet Earth.

[ugordan]

[seawolfe]

Just a reminder about this documentary showing in the U.K. tonight.

Documentary to be shown on BBC 4 in the U.K. on the 10th April.

How to See a Black Hole: The Universe’s Greatest Mystery

Documentary following researchers as they try to take the first-ever picture of a black hole. They must travel the globe to build a revolutionary telescope that spans planet Earth.

How about someone record this and either put it in L2 or on NSF's YouTube site?

[ugordan]

Seeing this initial result, I can't help but imagine the things we, as a species, could see with a big space-based network of satellites doing this kind of interferometry, without the problems of atmospheric vapor, inherently different instruments and the constraint of the diameter of our own planet (but of course with a host of other technical issues that would nevertheless not be insurmountable in the end).

Just imagine, a mere 3 years ago black holes were basically accepted as things that exist in our universe, but no one really had any *direct* evidence for it. Then came LIGO and the detection of gravitational waves and now this, the first ever image of the "shadow" of a supermassive black hole, unremarkable how it may or may not seem to the layman's eye. There are days I think it's good to be alive. This is one of them.

Also, how 'bout that old Einstein guy? Of course, this is still far from a precise test of GR in the strong gravity regime, but the fact that it's not *completely* and obviously different to what the theory predicts is remarkable. I'm not sure if I should be happy or sad for all the theoreticians who are seeking to unify GR and QM and could use any extra hint they could to guide their way.

[ugordan]

This is a nice visualization of what parts of the mess around a black hole can you see with different wavelengths and illustrates why the EHT went with a wavelength of around 1 mm:

[RonM]

Just a reminder about this documentary showing in the U.K. tonight.

Documentary to be shown on BBC 4 in the U.K. on the 10th April.

How to See a Black Hole: The Universe’s Greatest Mystery

Documentary following researchers as they try to take the first-ever picture of a black hole. They must travel the globe to build a revolutionary telescope that spans planet Earth.

How about someone record this and either put it in L2 or on NSF's YouTube site?

Can't do it because that would be a copyright violation. We don't want to get NSF in trouble.

[RotoSequence]

Also, how 'bout that old Einstein guy?

Let's also hear it for Roy Kerr, who found the solution for a rotating black hole 

[Star One]

Just a reminder about this documentary showing in the U.K. tonight.

Documentary to be shown on BBC 4 in the U.K. on the 10th April.

How to See a Black Hole: The Universe’s Greatest Mystery

Documentary following researchers as they try to take the first-ever picture of a black hole. They must travel the globe to build a revolutionary telescope that spans planet Earth.

How about someone record this and either put it in L2 or on NSF's YouTube site?

Can't do it because that would be a copyright violation. We don't want to get NSF in trouble.

The program should appear on that link I posted. I am not sure as regards viewed outside the UK.