AAO: Astronomers Shed Light on Different Galaxy Types

[bystander]

Astronomers Shed Light on Different Galaxy Types
Australian Astronomical Observatory | 2016 Sep 13

[img3="Stephan's Quintet -- Credit: NASA, ESA, and the Hubble SM4 ERO Team"]http://imgsrc.hubblesite.org/hu/db/imag ... lpaper.jpg[/img3][hr][/hr]

In research published today, Australian scientists have taken a critical step towards understanding why different types of galaxies exist throughout the Universe.

The research, made possible by cutting-edge AAO instrumentation, means that astronomers can now classify galaxies according to their physical properties rather than human interpretation of a galaxy’s appearance.

For the past 200 years, telescopes have been capable of observing galaxies beyond our own galaxy, the Milky Way.

Only a few were visible to begin with but as telescopes became more powerful, more galaxies were discovered, making it crucial for astronomers to come up with a way to consistently group different types of galaxies together.

In 1926, the famous American astronomer Edwin Hubble refined a system that classified galaxies into categories of spiral, elliptical, lenticular or irregular shape. This system, known as the Hubble sequence, is the most common way of classifying galaxies to this day.

Despite its success, the criteria on which the Hubble scheme is based are subjective, and only indirectly related to the physical properties of galaxies. This has significantly hampered attempts to identify the evolutionary pathways followed by different types of galaxies as they slowly change over billions of years. ...

The SAMI Galaxy Survey: The Link Between Angular Momentum and Optical Morphology - L. Cortese et al

• Monthly Notices of the RAS 463(1):170 (2016 Nov 21) DOI: 10.1093/mnras/stw1891
  arXiv.org > astro-ph > arXiv:1608.00291 > 01 Aug 2016

[bystander]

Scientists Unveil New 3D View of Galaxies
Australian Astronomical Observatory | 2017 Jul 27

For many years astronomers have struggled to get good-quality 3D data of galaxies. Although this technique is very powerful as it allows researchers to “dissect” objects, this was a slow process as each galaxy had to be observed independently.

Novel Australian designed and built instrumentation called the “Sydney-AAO Multi-object Integral-field” (SAMI) unit at the 3.9m Anglo-Australian Telescope (AAT) now allows astronomers to simultaneously view many galaxies at the same time. ...

The SAMI team has now released to the astronomical community the hiqh-quality 3D data of 772 galaxies (the “SAMI Data Release 1”, DR1). This is around 20% of the full galaxy sample (around 3600 galaxies) that will be obtained with the SAMI instrument at the AAT. ...

The SAMI Galaxy Survey: Data Release One with Emission-line Physics Value-Added Products - Andrew W. Green et al

• arXiv.org > astro-ph > arXiv:1707.08402 > 26 Jul 2017

[bystander]

Astronomers Spun Up by Galaxy-Shape Finding
ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO) | 2017 Sep 11

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For the first time astronomers have measured how a galaxy’s spin affects its shape.

It sounds simple, but measuring a galaxy’s true 3D shape is a tricky problem that astronomers first tried to solve 90 years ago.

“This is the first time we’ve been able to reliably measure how a galaxy’s shape depends on any of its other properties – in this case, its rotation speed,” ...

Galaxies can be shaped like a pancake, a sea urchin or a football, or anything in between.

Faster-spinning galaxies are flatter than their slower-spinning siblings, the team found.

“And among spiral galaxies, which have disks of stars, the faster-spinning ones have more circular disks,” ...

The SAMI Galaxy Survey: The Intrinsic Shape of Kinematically Selected Galaxies - C. Foster et al

• Monthly Notices of the RAS 472(1):966 (Nov 2017) DOI: 10.1093/mnras/stx1869

[MargaritaMc]

https://www.ras.org.uk/news-and-press/3 ... pe-finding

Background article in The Conversation by Caroline Foster and Richard McDermid
3D view helps us to understand how galaxies formed and evolved
September 11, 2017
https://theconversation.com/3d-view-hel ... lved-81318

[Ann]

Background article in The Conversation by Caroline Foster and Richard McDermid
3D view helps us to understand how galaxies formed and evolved
September 11, 2017
https://theconversation.com/3d-view-hel ... lved-81318

Thanks for posting this, Margarita! Very interesting!

Ann

[MargaritaMc]

Background article in The Conversation by Caroline Foster and Richard McDermid
3D view helps us to understand how galaxies formed and evolved
September 11, 2017
https://theconversation.com/3d-view-hel ... lved-81318

Thanks for posting this, Margarita! Very interesting!

Ann

My pleasure!