Go Back   IceInSpace > General Astronomy > Observational and Visual Astronomy
Register FAQ Calendar Today's Posts Search

Reply
 
Thread Tools Rate Thread
  #1  
Old 17-04-2008, 10:25 AM
glenc's Avatar
glenc (Glen)
star-hopper

glenc is offline
 
Join Date: Jun 2005
Location: Terranora
Posts: 4,406
Big and Bright Galaxy

I was just looking at the LEDA data for 4360 galaxies.
Only 19 of these galaxies have an absolute magnitude brighter than -23.
M 88 has an absolute magnitude of -23.1 and is one of the biggest and brightest galaxies out there. If it was 10 parsecs away (32.6 light years) it would be nearly as bright as our Sun (magnitude -26.7 for us). M 88 also has a high surface brightness and is easy to see with a visual magnitude of 9.3 and an elongated size of 8.7 x 4.4 arc min.
IC 4871 in Pav (mag 13.2, 3.8'x0.8') has the highest absolute magnitude (-25.3) in my list.
The definition of absolute magnitude is at:
http://en.wikipedia.org/wiki/Absolute_magnitude
Reply With Quote
  #2  
Old 17-04-2008, 10:12 PM
caleb
Registered User

caleb is offline
 
Join Date: Dec 2007
Location: gosford, australia
Posts: 206
-23, isnt that realy big. or bright, im unsure. But what do you think are the best gallaxies for my scope and how much detail.
Reply With Quote
  #3  
Old 18-04-2008, 01:15 AM
glenc's Avatar
glenc (Glen)
star-hopper

glenc is offline
 
Join Date: Jun 2005
Location: Terranora
Posts: 4,406
11 southern galaxies

Some bright southern galaxies are LMC, SMC, NGC55, NGC253, M77
NGC1291, NGC1316, NGC3115, NGC3521, M104 and M83.

The brightest objects in the sky have negative magnitudes:
Sun = -26.7, Full Moon = -12.5, Venus = -4.4, etc
The Sun and Moon are bright because they are close.
If the Sun was 10 parsecs away it would be magnitude +4.8.
M88 at the same distance would be magnitude -23.1.

See: http://www.historyoftheuniverse.com/magnitude.html
Reply With Quote
  #4  
Old 18-04-2008, 02:56 PM
ngcles's Avatar
ngcles
The Observologist

ngcles is offline
 
Join Date: Dec 2006
Location: Billimari, NSW Central West
Posts: 1,664
HI Glen & All,

On hols away down the south coast at the moment and don't have my resources with me but the two central galaxies in the Coma Cluster (I think NGC 4874 is one of the two) are up at around the -24.5 mark and make "monsters" like M87 look puny by comparison. From memory, the Milly Way which is an unusually massive if not bright spiral galaxy is at about the -21 mark. Galaxies with the highest absolute magnitude are bound to be elliptical types I'd think.

Best,

Les D
Contributing Editor
AS&T
Reply With Quote
  #5  
Old 18-04-2008, 03:20 PM
glenc's Avatar
glenc (Glen)
star-hopper

glenc is offline
 
Join Date: Jun 2005
Location: Terranora
Posts: 4,406
Here are the NGC and IC galaxies with absolute magnitudes brighter than -23.
Name, absolute mag.
IC0758, -25.57
IC4871, -25.25
NGC1262, -23.98
NGC0933, -23.78
NGC1615, -23.61
IC2980, -23.39
NGC3808B, -23.36
IC5032, -23.36
NGC4727, -23.2
NGC4953, -23.2
NGC4501, -23.1
NGC6040, -23.1
IC4312, -23.06
NGC6926, -23.05
IC2938, -23.04
Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 09:40 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement
Astrophotography Prize
Advertisement