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Author Topic: First Image Of Black Hole  (Read 955 times)

Offline sferrin

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Re: First Image Of Black Hole
« Reply #15 on: April 11, 2019, 07:03:01 am »
IR images of Milky Way galactic center showing stars rotating around a black hole (timelapse over years).  Originally done many years ago and repeated by other groups.  Chandra X-Ray telescope also looked at this area.

What are those things with the pulsing clouds around them one the left?  I'm assuming stars, but why would they show that cloudlike feature?
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Offline fredymac

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Re: First Image Of Black Hole
« Reply #16 on: April 11, 2019, 08:31:27 am »
Those look like Airy diffraction rings with a little turbulence modulation.  You would see that if you are looking at multiple stars of varying stellar magnitude (brightness).  The sensor is set to see the dim stars so the brighter stars start showing the ring pattern.  Stars are point sources and if you are looking at a limited wavelength band, the rings will be observable (as long as atmospheric turbulence doesn't blur them out).  To resolve the stars at the galactic center, you can either average multiple image frames to additively reduce the affect of turbulence, or use an adaptive optics system.  I would guess this montage was using an AO system.

Offline TomS

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Re: First Image Of Black Hole
« Reply #17 on: April 11, 2019, 08:49:43 am »
Turns out there really isn't just one image: they have a series from successive observations.

https://aasnova.org/2019/04/10/first-images-of-a-black-hole-from-the-event-horizon-telescope/

Now, what's confusing me is that the video posted above by Sferrin shows side-by-side images labeling one as SgrA*, but the article I just linked to indicates that they don't yet have images of SgrA*.

Offline galgot

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Re: First Image Of Black Hole
« Reply #18 on: April 11, 2019, 09:58:24 am »
From what I understand the M87 is the first image done from real data collected by Event Horizon. But they did a lot of simulated images from simulated data, and the real one matched almost perfectly the simulation (citing from the press conf…).
That SgrA* image is done from simulated data.
See here :


in the first comment of this vid :
Lukas Weih
21 hours ago
As there seems to be some general confusion, please note that the image shown here is a simulated one and not an actual image. So far we only have an image of M87.
Kind regards, the RelAstro group.
« Last Edit: April 11, 2019, 10:00:06 am by galgot »

Offline TomS

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Re: First Image Of Black Hole
« Reply #19 on: April 11, 2019, 10:08:26 am »
in the first comment of this vid :
Lukas Weih
21 hours ago
As there seems to be some general confusion, please note that the image shown here is a simulated one and not an actual image. So far we only have an image of M87.
Kind regards, the RelAstro group.


Ah, the perils of embedded video (where the comment isn't visible).  Thanks for clarifying. 

Offline Foo Fighter

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Re: First Image Of Black Hole
« Reply #20 on: April 12, 2019, 03:37:33 am »
Not very impressive to be honest, a bit of a damp squib.

Offline galgot

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Re: First Image Of Black Hole
« Reply #21 on: April 12, 2019, 04:00:09 am »
It's impressive as a scientific and material existence confirmation of what was up to now a math theory.
For sure it's not an hollywood like image of a black hole... We'll have to wait a bit for that .
First ever picts of Mars or Pluto weren't very impressive.

Offline Dragon029

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Re: First Image Of Black Hole
« Reply #22 on: April 12, 2019, 05:13:51 pm »
Not to mention this is (as far as I'm aware) an unprecedented antenna setup they've achieved here. Now that they've demonstrated the ability to do this (generate a virtual antenna aperture [resolution-wise, not gain-wise] the size of the entire planet), the door is opened to very high resolution imaging of other stellar objects (at least in the microwave / radio bands; high frequencies might be possible today, or if not they'll just inevitably come later).

Offline sienar

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Re: First Image Of Black Hole
« Reply #23 on: April 12, 2019, 11:56:59 pm »
Not to mention this is (as far as I'm aware) an unprecedented antenna setup they've achieved here. Now that they've demonstrated the ability to do this (generate a virtual antenna aperture [resolution-wise, not gain-wise] the size of the entire planet), the door is opened to very high resolution imaging of other stellar objects (at least in the microwave / radio bands; high frequencies might be possible today, or if not they'll just inevitably come later).

Imagine what could be done with a constellation of radio telescopes orbiting say 1.3 AU.

Offline Dragon029

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Re: First Image Of Black Hole
« Reply #24 on: April 13, 2019, 01:37:19 am »
Indeed, the only issue is data transfer; this photo required around 5 petabytes and it was easier for them to physically transport hard drives that transmit via fibre optic, etc. Space telescopes might just need to use laser transmitters and take a little extra time.

Offline Hobbes

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Re: First Image Of Black Hole
« Reply #25 on: April 13, 2019, 03:43:56 am »
Not to mention this is (as far as I'm aware) an unprecedented antenna setup they've achieved here. Now that they've demonstrated the ability to do this (generate a virtual antenna aperture [resolution-wise, not gain-wise] the size of the entire planet), the door is opened to very high resolution imaging of other stellar objects (at least in the microwave / radio bands; high frequencies might be possible today, or if not they'll just inevitably come later).

Coupling radio telescopes like this is not unprecedented, VLBI between telescopes on opposite sides of the Earth has been done for decades now. What's new here seems to be the amount and type of data processing used.

Offline Grey Havoc

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