ALMA watches Sgr A* twinkle

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notFritzArgelander
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ALMA watches Sgr A* twinkle

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Post by notFritzArgelander »

Note that this is the reason why the effort to image the event horizon failed but M87* succeeded,

https://phys.org/news/2020-05-alma-twin ... milky.html
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG
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Michael131313
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Re: ALMA watches Sgr A* twinkle

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Post by Michael131313 »

Thanks nFA. Is the distance to M87 the reason we do not see this type of variation or does M87 not have these types of accretion disc variations?
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notFritzArgelander
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Re: ALMA watches Sgr A* twinkle

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Post by notFritzArgelander »

Michael131313 wrote:
Sun May 24, 2020 1:49 am
Thanks nFA. Is the distance to M87 the reason we do not see this type of variation or does M87 not have these types of accretion disc variations?
Actually no! Good question!

Sgr A* is 4 million solar masses.
M87* is 2,400 billion solar masses.

So it’s 600,000 times more massive and larger in size similarly. The time scale for fluctuations is longer by the same factor.

Relativity requires the fluctuations be longer than the light speed crossing time roughly. So variations are slower and don’t blur the picture. :)
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG
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Re: ALMA watches Sgr A* twinkle

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Post by helicon »

I assume the mass of the black hole in M87 far exceeds that of Sagittarius A.
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Re: ALMA watches Sgr A* twinkle

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Post by notFritzArgelander »

helicon wrote:
Sun May 24, 2020 3:17 pm
I assume the mass of the black hole in M87 far exceeds that of Sagittarius A.
Yes by a factor of 600,000. The M87* object flickers more slowly by the same factor as you can see from these images.

https://aasnova.org/2019/04/10/first-im ... telescope/
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG
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