ALMA watches Sgr A* twinkle

Discuss Astrophysics.
Post Reply
User avatar
notFritzArgelander
In Memory
In Memory
Articles: 0
Offline
Posts: 14925
Joined: Fri May 10, 2019 4:13 pm
4
Location: Idaho US
Status:
Offline

TSS Awards Badges

ALMA watches Sgr A* twinkle

#1

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: AWB 130mm, f5, 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 IV, Vixen Porta II, Celestron CG5
User avatar
Michael131313 Mexico
Orion Spur Ambassador
Articles: 0
Offline
Posts: 966
Joined: Sun May 12, 2019 5:39 pm
4
Location: San Jose del Valle , Nayarit, Mexico
Status:
Offline

Re: ALMA watches Sgr A* twinkle

#2

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?
ES AR 102 102mm, f/6.5, ES 254mm f/5 DOB, Obie 10x50, GSO SV 30mm, ES 68° 20mm, ES 82° 14mm, 11mm, 8.8 mm, 6.8mm, 4.7mm. Twilight 1 mount.
User avatar
notFritzArgelander
In Memory
In Memory
Articles: 0
Offline
Posts: 14925
Joined: Fri May 10, 2019 4:13 pm
4
Location: Idaho US
Status:
Offline

TSS Awards Badges

Re: ALMA watches Sgr A* twinkle

#3

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: AWB 130mm, f5, 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 IV, Vixen Porta II, Celestron CG5
User avatar
helicon United States of America
Co-Administrator
Co-Administrator
Articles: 584
Online
Posts: 12275
Joined: Mon May 06, 2019 1:35 pm
4
Location: Washington
Status:
Online

TSS Awards Badges

Re: ALMA watches Sgr A* twinkle

#4

Post by helicon »


I assume the mass of the black hole in M87 far exceeds that of Sagittarius A.
-Michael
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
Binoculars: Celestron SkyMaster 15x70, Bushnell 10x50
Eyepieces: Various, GSO Superview, 9mm Plossl, Celestron 25mm Plossl
Camera: ZWO ASI 120
Naked Eye: Two Eyeballs
Latitude: 48.7229° N
User avatar
notFritzArgelander
In Memory
In Memory
Articles: 0
Offline
Posts: 14925
Joined: Fri May 10, 2019 4:13 pm
4
Location: Idaho US
Status:
Offline

TSS Awards Badges

Re: ALMA watches Sgr A* twinkle

#5

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: AWB 130mm, f5, 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 IV, Vixen Porta II, Celestron CG5
Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

Return to “Astrophysics”