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#20
by
as58
on 01 Apr, 2019 19:20
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I'm thinking Sgr A*, just because it's a bigger impact as it's in our backyard and not some "random" galaxy out there.
Actually, are there any other plausible targets? Messier 87 is by far the closest of the really massive ones.
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#21
by
ugordan
on 01 Apr, 2019 19:33
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I'm thinking Sgr A*, just because it's a bigger impact as it's in our backyard and not some "random" galaxy out there.
Actually, are there any other plausible targets? Messier 87 is by far the closest of the really massive ones.
There's a third one I've seen mentioned in a talk by Avery Broderick (one of the panelists for the press conference), but he said it's not radio-active so we're out of luck. Those two are the best candidates nearby.
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#22
by
Star One
on 01 Apr, 2019 20:21
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Are there any plans to add the Tianyan radio telescope to this collective?
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#23
by
jgoldader
on 02 Apr, 2019 01:19
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I'm thinking Sgr A*, just because it's a bigger impact as it's in our backyard and not some "random" galaxy out there.
Actually, are there any other plausible targets? Messier 87 is by far the closest of the really massive ones.
M87 is the best one besides Sgr A*, and I would be surprised if there are many (any?) others that could be resolved. The angular size of the event horizon is proportional to the linear diameter divided by the distance; yet because the linear diameter of the event horizon is proportional to the black hole mass, M87's greater mass almost compensates for its greater distance. The end result is that the angular diameter of the M87 black hole's event horizon should be a little less than that of Sgr A*.
I'm trying not to get too hopeful; the renders in "Interstellar" were based on real physics (tweaked for cinematography) and seeing a ring would be just spectacular.
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#24
by
as58
on 02 Apr, 2019 05:06
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Are there any plans to add the Tianyan radio telescope to this collective?
No, it works at much longer wavelengths than the telescopes that are used in EHT.
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#25
by
hoku
on 02 Apr, 2019 10:08
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Just a few numbers, which might come in handy for the discussion of the EHT results (of which I do not know anything). The Schwarzschild radius (notice spelling "schild"!) of a black hole is 3 km times the mass of the black hole in solar masses. For a non-rotating black hole this also defines the location of the event horizon.
Sgr A*:
mass: 4.2 million solar masses
RADIUS: 12.5 million km
DIAMETER: 25 million km (15.5 million miles)
angular DIAMETER (for a distance Sun to Sgr A* of 8200 pc): 20 micro-arcsec
RADIUS of innermost stable orbit (for non-rotating black hole): 3 * Scharzschild radius = 30 micro-arcsec
EHT (present configuration?):
observing frequency: 230 GHz (i.e. observing wavelength 1.3mm)
angular resolution EHT for, e.g., Hawaii - ALMA baseline: 28 micro-arcsec
(see
https://eventhorizontelescope.org/building-larger-array)
Results of previously highest angular resolution radio (at 86 GHz, i.e. 3.5 millimeter) observations of Sgr A*:
https://www.mpifr-bonn.mpg.de/pressreleases/2019/1
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#26
by
Star One
on 06 Apr, 2019 12:04
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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 MysteryDocumentary 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.
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#27
by
Star One
on 06 Apr, 2019 19:21
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#28
by
eeergo
on 10 Apr, 2019 13:00
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Press conference event starting (6 different ones going on at the same time in Brussels (English), Shanghai (Mandarin Chinese), Taipei (Mandarin Chinese), Tokyo (Japanese), Santiago de Chile (Spanish) and Washington DC (English); I'm looking at the main one from Europe).
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#29
by
eeergo
on 10 Apr, 2019 13:08
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#30
by
eeergo
on 10 Apr, 2019 13:09
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10^11 (100 billion in English numbering) km diameter.
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#31
by
eeergo
on 10 Apr, 2019 13:10
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6.5·10^9 (billion in English numbering) times the Sun's mass.
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#32
by
eeergo
on 10 Apr, 2019 13:13
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#33
by
FutureSpaceTourist
on 10 Apr, 2019 13:14
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#34
by
eeergo
on 10 Apr, 2019 13:15
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Tens of thousands of synthetic images generated to be sure the acquired one really is a BH.
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#35
by
Star One
on 10 Apr, 2019 13:16
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Any news about the imaging of sagittarius a?
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#36
by
eeergo
on 10 Apr, 2019 13:19
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Had to wait for all observing sites to have good weather simultaneously to perform the interferometry and get an effective radiotelescope of Earth's size, record everything in hard drives (no fiber optic infrastructure), fly boxes full of HDs (6 m^3 of volume!) to a data processing center where careful checks taking months took place, to arrive to this image.
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#37
by
eeergo
on 10 Apr, 2019 13:20
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Shadow first seen by individual researchers on their ordinary laptops, while they worked on merging their data to get maximum resolution and reliability.
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#38
by
eeergo
on 10 Apr, 2019 13:22
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Clockwise rotating hole.
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#39
by
eeergo
on 10 Apr, 2019 13:23
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6 papers coming out now in astrophysical journals explaining the details.