Try increasing gamma if dark sections aren't distinguished

Try increasing gamma if dark sections aren't distinguished

Thursday, April 18, 2019

Messier 87 the smoking gun galaxy

Messier 87, the smoking gun, is a super giant galaxy--over a trillion  stars--in the constellation Virgo.  M 87 lies 55 million light years away, at the center of the Virgo supercluster which includes our local galaxy group. 

Images of the black hole at the center of M87 were released last Wednesday, 4/10/19.  Inspired by the image, I photographed the galaxy from my backyard that night. 

At low power, M 87 looks like a boring elliptical galaxy, just round blob of light (see following post).  This close up shot from 4/10/19 shows blue "smoke" rising out of the core to the right which is actually plasma ejected from the core as the black hole devours matter.  

M 87 close up
streak of blue plasma projects up and to the right
Needless to say, the resolution of this image is not fine enough to capture the black hole.  The scale of this image is 0.4 arc seconds (angular measurement, as in degrees, minutes, and seconds) per pixel.  However, due to atmospheric distortion, the resolution of the image is about 2.0 arc seconds (FWHM).  On a good night, i can capture images below 2 arc second resolution, the best i've ever captured (once) was just under 1 arc second.  For reference, the resolution of the Hubble space telescope is typically 0.1 arc second.  The resolution of the event horizon telescope that captured the black hole was .00002 arc seconds.  

Here's the Event Horizon Telescope image:
Event Horizon Telescope Image of the supermassive black hole (6.5 billion solar masses) in the center of the galaxy M 87


How can you get such amazing resolution? 
The resolution of a telescope is limited by it's diameter.  However, if you can combine the signal captured by multiple telescopes at the same time, the resolution is limited by the distance between the telescopes.  The event horizon telescope combined images captured by an array of radio telescopes all around the globe (including the south pole) giving an effective diameter approaching the size of the planet earth.  Interestingly, i've heard that the release of the image was partially delayed by having to physically transport a hard drive from the south pole (which cannot be easily reached all year round).  

The phenomena surrounding a black hole are truly amazing: of course at the event horizon no light can escape the gravitational pull of the black hole.  But beyond that is an area where photons themselves orbit the black hole multiple times.  creeping out from this are areas where light may bend 270 degrees: so if you look on the left side of a black hole, you'll see an image from the black hole facing left.  beyond that 180 degrees, so you'll see the image of our own galaxy reflected back, further out 90 degrees, so you'll see an image from the black hole facing right...
Here's a trippy youtube video simulating this phenomenon while two black holes are merging:


And here's an interesting video giving more detail on the light bending phenomena near a black hole:




Details:
8" LX200R, SX Trius 694 0.4"/px, ASA DDM60
astrodon LRGB E SERIES GEN-II
Luminance 4/10/19
12 of 46 120 second subs, 7 of 63 60 second subs
(threw out all with FWHM >5.5 pixels)
RGB 4/12/19
15x120 sec each channel
fair seeing (excluded ~2/3 subs)
the jet is very bright, the image is a simple linear stretch without sharpening
Eastbluff, CA Bortle white

EHT press release with more details on the black hole image:
https://eventhorizontelescope.org/

 A bit more science:
The Astrophysical Journal Letters
https://iopscience.iop.org/journal/2041-8205/page/Focus_on_EHT

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