UCR: Large Number of Dwarf Galaxies Discovered in the Early Universe

[bystander]

Large Number of Dwarf Galaxies Discovered in the Early Universe
University of California, Riverside | 2016 Nov 21

A UC Riverside-lead team of astronomers has discovered a large number of dwarf galaxies in the early universe by using the gravitational lensing phenomenon, completing astronomers’ census of star-forming galaxies in that epoch

[img3="Massive cluster of galaxies Abell 1689 creates a strong gravitational
effect on background and older galaxies, seen as arcs of light.
Image credit: NASA, ESA, B. Siana, and A. Alavi"]https://ucrtoday.ucr.edu/wp-content/upl ... laxies.jpg[/img3][hr][/hr]

A team of researchers, led by University of California, Riverside astronomers, found for the first time a large population of distant dwarf galaxies that could reveal important details about a productive period of star formation in the universe billions of years ago.

The findings, just published in The Astrophysical Journal, build on a growing body of knowledge about dwarf galaxies, the smallest and dimmest galaxies in the universe. Though diminutive, they are incredibly important for understanding the history of the universe.

It is believed that dwarf galaxies played a significant role during the reionization era in transforming the early universe from being dark, neutral and opaque to one that is bright, ionized and transparent.

Despite their importance, distant dwarf galaxies remain elusive, because they are extremely faint and beyond the reach of even the best telescopes. This means that the current picture of the early universe is not complete.

However, there is a way around this limitation. As predicted by Einstein’s general theory of relativity, a massive object such as a galaxy located along the line of sight to another distant object, can act as a natural lens, magnifying the light coming from that background source.

This phenomenon, known as gravitational lensing, causes the background object to appear brighter and larger. Therefore, these natural telescopes can allow us to discover unseen distant dwarf galaxies. ...

The Evolution of the Faint End of the UV Luminosity Function During the Peak Epoch of Star Formation (1<z<3) - Anahita Alavi et al

• Astrophysical Journal 832(1):56 (20 Nov 2016) DOI: 10.3847/0004-637X/832/1/56
  arXiv.org > astro-ph > arXiv:1606.00469 > 01 Jun 2016 (v1), 11 Oct 2016 (v2)

[neufer]

<<In the fantasy of J. R. R. Tolkien, the Dwarves are portrayed as a very ancient people inhabiting Middle-earth who awoke at the start of the First Age, before the existence of the Sun and Moon. In Tolkien's works, the Dwarves were created during the Ages of Darkness, when all of Middle-earth was controlled by the forces of Melkor. Aulë sealed the seven Fathers of the Dwarves in stone chambers in far-flung regions of Middle-earth to await their awakening. Some time after the Elves had awakened at Cuiviénen, the Seven Fathers of the Dwarves were released from their stone chambers.>>

[Ann]

<<In the fantasy of J. R. R. Tolkien, the Dwarves are portrayed as a very ancient people inhabiting Middle-earth who awoke at the start of the First Age, before the existence of the Sun and Moon. In Tolkien's works, the Dwarves were created during the Ages of Darkness, when all of Middle-earth was controlled by the forces of Melkor. Aulë sealed the seven Fathers of the Dwarves in stone chambers in far-flung regions of Middle-earth to await their awakening. Some time after the Elves had awakened at Cuiviénen, the Seven Fathers of the Dwarves were released from their stone chambers.>>

Right. But I don't remember the dwarves of Tolkien being blue in color or UV-bright.

Ann

[neufer]

I don't remember the dwarves of Tolkien being blue in color or UV-bright.

[b][color=#0000FF][size=150]Location of the Blue Mountains in Middle-earth.[/size][/color][/b]

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<<The Blue Mountains, the Iron Hills, and Lonely Mountain were the main areas of Dwarf colonization by the late Third Age. During the 4000+ years following the cataclysmic sundering and catastrophic downfall of Beleriand, when the mighty Dwarf fortress-cities of Nogrod and Belegost were inundated by the sea, it is possible that the Dwarves rebuilt those cities to their former splendor.

The Dwarves would have plundered the mines of the Blue Mountains for the hoard of resources it held within the depths of darkness at its roots.

Before setting off in their quest to the Lonely Mountain, Thorin Oakenshield and his twelve other companions (as well as other Dwarves of the Lonely Mountain) resided here in the Blue Mountains after being rendered homeless by the Dragon Smaug.

After the War of the Ring, many Dwarves from the eastern kingdoms migrated back to the Blue Mountains. Their population grew and the Blue Mountains became a prosperous kingdom once again.

The Blue Mountains arose sometime after the tumultuous chaos caused by Melkor's destruction of the Two Lamps that destroyed the perfect symmetry of Arda. In these early days, the Blue Mountains were located between the newly formed great sea of Belegaer and the newly formed Sea of Helcar. The Blue Mountains were connected to the Iron Mountains to the north and the Red Mountains in the east which formed one great mountain range chain known by different names. The Ancient Grey Mountains were to its south separated by a great gap.

During the Years of the Trees and the Sleep of Yavanna, the Blue Mountains was an unbroken line separating Eriador from Beleriand. Seven rivers arose in it on the western side, and the land these rivers flowed through was known as Ossiriand, which was later also as Lindon, therefore the mountains were sometimes referred to as the Ered Lindon. Dwarven kinfolk either awoke here or migrated here from other awakening points and delved the cities of Belegost and Nogrod and made contact and alliance with the Sindar of Thingol.

The mountain range was broken during the war of the Valar against Morgoth, and at the middle of the range the sea broke through, creating a great gap where was set the Gulf of Lune a new terminus for the river Lune. In the middle of the gap, where the Lune met the sea, the Grey Havens of Mithlond of the Elven Kingdom of Lindon were built. When seen as the border of Lindon the Ered Luin were called Ered Lindon.

During the Third Age, its forests, besides that of Mirkwood, were the largest in Middle-earth. In the latter part of the Third Age, the Dwarves settled the Blue Mountains again when Thráin II and his son Thorin and the Dwarven survivors of the Sack of Erebor moved from Dunland and delved a prosperous settlement there. After the War of the Ring and the defeat of Sauron, Elves continued to travel west to Lindon through the gap in the mountains by way of the Gulf of Lune, where they eventually intended to set sail on the Straight Road to the Undying Lands of Aman. After the War of the Ring it is said that many Dwarves from the east migrated back to their ancient homeland and Ered Luin was a prosperous kingdom oncemore.>>