This Dwarf galaxy is quite bright - mag 9.9 - at 2.38 million lyrs away closer to us than M31 and has a blue shift. Somewhere in Cetus near Pisces it is really not imaged much but has a large HII regions. It was discovered in 1906 and I noticed it in CCD Calc so thought I would give it a try as you don't see it imaged often, even though it is quite large at 16x14 arc min.
John,
I enjoyed your image of this cute little irregular galaxy.
The rate of star formation must be low.
We are currently discussing another small irregular galaxy in the Local Group of Galaxies, in the science forum:
"the WLM system"
(Wolf-Lundmark-Melotte galaxy)
A comprehensive recent discussion, with many data tables, of all of the galaxies in and near the Local Group, can be found in this .pdf :
Hi John,
Your images are true inspiring and this dwarf galaxies is not different. The clean background shows lots of other small galaxies up there, not to mention all the details of the HII region.
Thank you for sharing this beauty.
Fernando
PS:
Robert: Thanks for the pdf with the great report presenting data of so many ""nearby"" dwarf galaxies.
Hey that's excellent John! I saw this in my image search actually but it didn't make the cut... so I'm glad you decided to shoot it, as it looks very cool, nicely processed
Thanks for the comments everyone, though this might be a bit unusual but the HII region made it worthwhile. There are so many unimaged unusual objects around I keep finding.
Nice imaging John, yeah never seen this target, rather interesting, looks like a Glob gone wrong in a way at this resolution.
Them Red HII regions, are they part of thie galaxy, i assums so ! Hey, that lower red HII object appears to have some arms reaching out of it, any idea what the go is there ?
Facinating
Nice imaging John, yeah never seen this target, rather interesting, looks like a Glob gone wrong in a way at this resolution.
Them Red HII regions, are they part of thie galaxy, i assums so ! Hey, that lower red HII object appears to have some arms reaching out of it, any idea what the go is there ?
Facinating
The HII structures inside IC1613 are in the form of giant shells believed to be supernovae driven or driven by some of the massive blue supergiant stars in the area but nobody is entirely sure.
The lower HII region I imaged with one 5min Binx2 OIII sub and the lower region was the only patch to show up, but I did not think it was good enough to try a set.
There is a NASA image I found but quality is not so good.
The HII structures inside IC1613 are in the form of giant shells believed to be supernovae driven or driven by some of the massive blue supergiant stars in the area but nobody is entirely sure.
John.
John,
IC 1613 and NGC 6822 and the WLM galaxy are much more typical of dwarf irregular galaxies than relatively high surface brightness examples like the LMC and NGC 4449
In essence, dIrr galaxies, unless they happen to be undergoing a vigorous (and episodic) starburst, continue to form very massive and luminous young stars, which energize HII regions, but they form these young hot blue stars at a low rate.
One of my absolute favourite dwarf irregular galaxies that is undergoing a burst of star formation is IC 4662 ; this tiny dwarf galaxy nevertheless contains two giant HII regions, which I have even seen visually with a 10 inch.
However, it is rare to find a dwarf irregular which has Ha emission all over it.
The stars that energize HII regions burn out in a few million years, which is a blink of an eye on a cosmic timescale, so HII emission traces what is usually called the most recent star formation.
All of those pretty HII regions that we see in our images might be gone in a short while, perhaps within a million years time, as the stars that energize them become red supergiants and stop producing that short wavelength UV that is necessary to make them gently glow.
cheers,
Robert
P.S. When I say "HII region", I also include all regions of ionized hydrogen, including supershells energized by supernovae and including diffuse Halpha emission.
(HII , technically, refers to any region of Ha emission)
Of course it is strange of astronomers to use the words "recent" when they mean within the last 10 million years, and "very recent" when they mean within the last 1 or 2 million years....
especially considering that if I live a hundred years, a million years is still ten thousand times my life-span!
Last edited by madbadgalaxyman; 29-11-2013 at 12:07 PM.
