Spiral-like patterns of star formation discovered in old galaxies

November 22, 2016, Instituto de Astrofísica e Ciências do Espaço
Credit: Instituto de Astrofísica e Ciências do Espaço

Using data from the SDSS and CALIFA surveys, a team of astronomers, led by Jean Michel Gomes and Polychronis Papaderos from the Instituto de Astrofísica e Ciências do Espaço (IA), in Portugal, discovered in the optical faint star-forming spiral-arm-like features in the periphery of nearby early-type galaxies. This work was presented yesterday, during the 2nd SELGFIS Advanced School on Integral-Field Spectroscopic Data Analysis , ongoing in Madrid until the 25th of November 2016.

Usually, star-forming regions are blue areas, HII-regions that house short-lived massive blue stars, embedded in the disk section of spiral galaxies. In contrast, Elliptical and Lenticular galaxies (historically referred to as early-type galaxies) are composed of old stars with reddish colors, and are thought to be "dead" spheroids, no longer giving birth to new stars.

However, the CALIFA study led by the IA team has now discovered in the optical spiral features in the outskirts of three nearby early-type galaxies, which points to a still ongoing inside-out growth. This adds valuable observational insight into the origin and evolution of spiral structures in old spheroidal galaxies.

Jean Michel Gomes (IA & University of Porto), co-leader of the SELGIFS work package Reconstruction of the Star Formation History explains the novelty of this discovery: "According to our current view, grand design spiral-like features are associated with disc galaxies. These are, in general, regions of enhanced star formation. We were surprised to have discovered, for the first time in the optical, spiral-like structures in early-type galaxies, which we believed to have stopped forming stars in the last few billion years and should entirely lack spiral features."

Credit: Instituto de Astrofísica e Ciências do Espaço

The discovery of faint spiral-like star-forming features in the periphery of early-type galaxies in this pilot study by Gomes and Papaderos has already motivated a further investigation of this issue by researchers at IA.

To Polychronis Papaderos (IA & University of Porto), founding member and Co-Investigator of SELGIFS and scientist in charge of its Portuguese node: "This study provides further observational evidence for a still ongoing growth of some seemingly "old and dead" early-type galaxies in the local Universe, out of a reservoir of cold gas that feeds low-level star-forming activity in their periphery".

IA researchers Gomes and Papaderos, together with their PhD students Iris Breda and Sandra Reis, are leading a research within the CALIFA collaboration, on the properties of the diffusely distributed warm ionized gas in early-type galaxies. The main goal of this project is to evaluate the role of various possible gas excitation mechanisms in early-type .

Credit: Instituto de Astrofísica e Ciências do Espaço
Credit: Instituto de Astrofísica e Ciências do Espaço

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8 comments

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Tuxford
1 / 5 (3) Nov 22, 2016
We were surprised to have discovered, for the first time in the optical, spiral-like structures in early-type galaxies, which we believed to have stopped forming stars in the last few billion years and should entirely lack spiral features."


Surprise! Not to me. I have been saying this since my first post in 2010. Galaxies grow from the inside out, not the reverse as the merger maniacs insists.

...has now discovered in the optical spiral features in the outskirts of three nearby early-type galaxies, which points to a still ongoing inside-out growth. This adds valuable observational insight into the origin and evolution of spiral structures in old spheroidal galaxies.


No valuable insight to the merger maniac, who simply lacks capacity for additional insight. Observations are not considered in the face of his favorite fantasy. Merger mania forever!
RNP
3.7 / 5 (3) Nov 22, 2016
@Tuxford
Can you present one SHRED of evidence for your outrageous claims? Can you suggest a SINGLE physical process that could generate matter in the way you suggest? Can you name ONE serious scientist that entertains your ideas?

If not, you can not expect to be taken seriously by anybody reading your posts.

FredJose
1 / 5 (3) Nov 23, 2016
This adds valuable observational insight into the origin and evolution of spiral structures in old spheroidal galaxies.

Sorry to burst your bubble dear researcher, but it does not. There is NOTHING that we can currently observe or deduce that actually can tell us about the origins and "evolution" of stars and hence spiral structures that exist in the universe today.
One cannot go back into the past via the observations we have today because we do not have ANY recorded actual history whatsoever about star formation. Hence there is nothing to
learn from this. Unless and until we actually get to see a star form from a cloud of gas all by itself, your are simply chasing your own tail. That's normally what the phrase "gives valuable/new insight" means in this case - you learned nothing and are still as in the dark as ever.
RNP
4.2 / 5 (5) Nov 23, 2016
@FredJose
.....Unless and until we actually get to see a star form from a cloud of gas all by itself, your are simply chasing your own tail.


How mind-bogglingly silly can you be! Surely you must understand the timescales involved!

ANY understanding of processes on these timescales must be gleaned by studying multiple systems at various stages in their lives/evolution. This is true in all similar sciences (e.g. geology, paleontology, evolutionary biology....).

Are you suggesting that no science can be performed in these fields unless we can actually "see" these processes in action.
geokstr
5 / 5 (3) Nov 25, 2016
This adds valuable observational insight into the origin and evolution of spiral structures in old spheroidal galaxies.

Sorry to burst your bubble dear researcher, but it does not. There is NOTHING that we can currently observe or deduce that actually can tell us about the origins and "evolution" of stars and hence spiral structures that exist in the universe today.
One cannot go back into the past via the observations we have today because we do not have ANY recorded actual history whatsoever about star formation. Hence there is nothing to
learn from this. Unless and until we actually get to see a star form from a cloud of gas all by itself, your are simply chasing your own tail. That's normally what the phrase "gives valuable/new insight" means in this case - you learned nothing and are still as in the dark as ever.


Well, it's obvious what your "theory" of star formation is - it's called the "Hallelujah! It's a Miracle! GODDIDIT! Theory of Everything".
antialias_physorg
5 / 5 (3) Nov 25, 2016
Unless and until we actually get to see a star form from a cloud of gas all by itself, your are simply chasing your own tail.

...and yet you believe in a god that neither you - nor anyone else for that matter - has ever observed. Not now or in the past. Hypocrit, much?

You are one strange creature.
Tuxford
1 / 5 (2) Nov 27, 2016
has now discovered in the optical spiral features in the outskirts of three nearby early-type galaxies, which points to a still ongoing inside-out growth.

Inside-out, upside-down, to and fro...

Want to see some more rings? No need to go far. Check out Andromeda. Both the old and the new behaving similarly in a finite aged Huge Bang Fantasy. Don't think so...

http://phys.org/n...eda.html
Whydening Gyre
5 / 5 (1) Nov 28, 2016
This adds valuable observational insight into the origin and evolution of spiral structures in old spheroidal galaxies.

...currently observe or deduce that actually can tell us about the origins and "evolution" of stars and hence spiral structures that exist in the universe today. ...

Spirals are a function of gravitational influence. They are simply a part of how the Universe organizes.

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