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ESA/Hubble: Galaxies in Miniature

Posted: Tue Jul 30, 2024 7:43 am
by Ann
ESA/Hubble:

Galaxies in Miniature

ESA/Hubble wrote:

The Hubble Picture of the Week this week reveals the subtle glow of the galaxy named IC 3430, located 45 million light-years from Earth in the constellation Virgo. It is part of the Virgo cluster, a rich collection of galaxies both large and small, many of which are very similar in type to this diminutive galaxy.

IC 3430 is a dwarf galaxy, a fact well reflected by this view from Hubble, but it is more precisely known as a dwarf elliptical or dE galaxy. Like its larger cousins, this galaxy has a smooth, oval shape lacking any recognisable features like arms or bars, and it is bereft of gas to form very many new stars. Interestingly, IC 3430 does feature a core of hot, massive blue stars, an uncommon sight in elliptical galaxies that indicates recent star-forming activity. It’s believed that ram pressure from the galaxy ploughing through gas within the Virgo cluster has ignited what gas does remain in IC 3430’s core to form some new stars.

For myself, I note that there are other oval-shaped seemingly elliptical dwarf galaxies that are forming stars at their centers, sometimes at a high rate. Two examples are NGC 3077 and NGC 5253.


NGC 3077 and NGC 5253 are true starburst galaxies, whereas in NGC 3430 we see relatively modest star formation. Even so, the phenomena may be related.

Ann

Re: ESA/Hubble: Galaxies in Miniature

Posted: Tue Jul 30, 2024 11:26 pm
by saturno2
Thanks, Ann
Very interesting your explanation

Re: ESA/Hubble: Galaxies in Miniature

Posted: Sun Aug 11, 2024 7:38 pm
by AVAO
Ann wrote: Tue Jul 30, 2024 7:43 am ESA/Hubble:

Galaxies in Miniature

ESA/Hubble wrote:

The Hubble Picture of the Week this week reveals the subtle glow of the galaxy named IC 3430, located 45 million light-years from Earth in the constellation Virgo. It is part of the Virgo cluster, a rich collection of galaxies both large and small, many of which are very similar in type to this diminutive galaxy.

IC 3430 is a dwarf galaxy, a fact well reflected by this view from Hubble, but it is more precisely known as a dwarf elliptical or dE galaxy. Like its larger cousins, this galaxy has a smooth, oval shape lacking any recognisable features like arms or bars, and it is bereft of gas to form very many new stars. Interestingly, IC 3430 does feature a core of hot, massive blue stars, an uncommon sight in elliptical galaxies that indicates recent star-forming activity. It’s believed that ram pressure from the galaxy ploughing through gas within the Virgo cluster has ignited what gas does remain in IC 3430’s core to form some new stars.

For myself, I note that there are other oval-shaped seemingly elliptical dwarf galaxies that are forming stars at their centers, sometimes at a high rate. Two examples are NGC 3077 and NGC 5253.


NGC 3077 and NGC 5253 are true starburst galaxies, whereas in NGC 3430 we see relatively modest star formation. Even so, the phenomena may be related.

Ann
For NGC 3077 I like the image of Hypatia Alexandria even though she has since switched back to earthly subjects in her photography.
Click to view full size image
Interestingly, NGC 3077 interacts with M81 and M82.
Click to view full size image
Image via William Ostling/ Andre Vilhena/ Dominic/ Jens Unger/ Justin P./ Steve Gill/ Ovidiu Dascalu/ W. J. G. de Blok et al.

There are also certain minimal similarities between NGC 3077 and M82 in particular. However, the star formation in NGC 3077 can clearly be explained from the interaction with the other two galaxies. In IC 3430, star formation is also present in its center, but very low in comparison.
But IC3430 also has two optical neighbors, NGC 4483 and NGC 4469, although these should be much closer due to the smaller redshift.
Click to view full size image
NGC 4469 is also interesting in terms of its core region. However, the GALEX data indicate that there are relatively few bright or young stars there.
Click to view full size image
Credit: NASA/ESA (Wikimedia)

And yes, I think NGC 5253 is very similar to M82.
Click to view full size image
Click to view full size image
Original data: NASA/ESA jac berne (flickr)