News:

Nitpicky? Hell yes.

Main Menu

More 'Spindle-Like' Galaxies

Started by Recusant, October 15, 2017, 04:31:18 PM

Previous topic - Next topic

Recusant

There is an unusual type of blimp-shaped galaxy which rotates on its long axis. These 'prolate elliptical' galaxies were previously considered to be extremely rare. A new study has shown that there are more of them out there, though still not a lot. The same study has proposed a model explaining how these galaxies formed from a particular type of collision between two spiral galaxies.



"Astronomers discover unusual spindle-like galaxies" | PhysOrg

Quote

An elliptical galaxy in prolate rotation. The galaxy resembles the shape of a cigar, with its stars rotating around the galaxy's long axis, similar to a spindle. the background image is a snapshot of a simulation by A. Tsatsi and colleagues. Image credit: J. Chang, PMO / T. Müller, HdA




Galaxies are majestic, rotating wheels of stars? Not in the case of the spindle-like galaxies studied by Athanasia Tsatsi (Max Planck Institute for Astronomy) and her colleagues. Using the CALIFA survey, the astronomers found that these slender galaxies, which rotate along their longest axis, are much more common than previously thought. The new data allowed the astronomers to create a model for how these unusual galaxies probably formed, namely out of a special kind of merger of two spiral galaxies. The results have been published in the journal Astronomy & Astrophysics.

When most people think of galaxies, they think of majestic spiral galaxies like that of our home galaxy, the Milky Way: billions of stars, rotating in a flat disk similar to the way that a wheel rotates around its central axis. But there is another kind of galaxy, which used to be thought very rare: so-called prolate rotators, each shaped like a cigar, which rotates along its long axis, like a spindle.

Now, a group of astronomers led by Athanasia Tsatsi of the Max Planck Institute for Astronomy has completed a thorough study of these cosmic spindles. Using data from the CALIFA survey, a systematic study that examined the velocity structure of more than 600 galaxies, the astronomers discovered eight new prolate rotating galaxies, almost doubling the total known number of such galaxies (from 12 to 20). Cosmic spindles are considerably less rare than astronomers had thought!

Given the high quality of their data, the astronomers were able to propose a plausible explanation for how these cosmic spindles come into existence. In general, galaxies grow when they merge with other galaxies. Several mergers with smaller galaxies have made our own Milky Way the stately disk it is today. To make a cosmic spindle, two large disk galaxies need to collide at right angles [as shown in the animation above].


[Continues . . .]
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Dave

Interesting.

Disc and barred galaxies, in rotation, seem "natural", centrifugal forces throwing the stars outwards. But then I thought of the mutual gravity fields.

Glad I don't have to get my head around these sort of things, and would it have been possible to get a decent guess before modelling on supercomputers?
Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74

xSilverPhinx

Quote from: Dave on October 15, 2017, 05:55:38 PM
Disc and barred galaxies, in rotation, seem "natural", centrifugal forces throwing the stars outwards. But then I thought of the mutual gravity fields.

Mutual gravity fields are not enough, dark matter keeps stars from going rogue. :smilenod:
I am what survives if it's slain - Zack Hemsey


Dave

Quote from: xSilverPhinx on October 16, 2017, 12:18:08 AM
Quote from: Dave on October 15, 2017, 05:55:38 PM
Disc and barred galaxies, in rotation, seem "natural", centrifugal forces throwing the stars outwards. But then I thought of the mutual gravity fields.

Mutual gravity fields are not enough, dark matter keeps stars from going rogue. :smilenod:

Oops, yes, forgot that!
Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74