Subscribe free to our newsletters via your
. Space Travel News .




STELLAR CHEMISTRY
ALMA witnesses assembly of galaxies in the early universe
by Staff Writers
Munich, Germany (SPX) Jul 24, 2015


This view is a combination of images from ALMA and the Very Large Telescope. The central object is a very distant galaxy, labelled BDF 3299, which is seen when the Universe was less than 800 million years old. The bright red cloud just to the lower left is the ALMA detection of a vast cloud of material that is in the process of assembling the very young galaxy. Image courtesy ESO/R. Maiolino. For a larger version of this image please go here.

When the first galaxies started to form a few hundred million years after the Big Bang, the Universe was full of a fog of hydrogen gas. But as more and more brilliant sources - both stars and quasars powered by huge black holes - started to shine they cleared away the mist and made the Universe transparent to ultraviolet light [1].

Astronomers call this the epoch of reionisation, but little is known about these first galaxies, and up to now they have just been seen as very faint blobs. But now new observations using the power of ALMA are starting to change this.

A team of astronomers led by Roberto Maiolino (Cavendish Laboratory and Kavli Institute for Cosmology, University of Cambridge , United Kingdom) trained ALMA on galaxies that were known to be seen only about 800 million years after the Big Bang [2]. The astronomers were not looking for the light from stars, but instead for the faint glow of ionised carbon [3] coming from the clouds of gas from which the stars were forming. They wanted to study the interaction between a young generation of stars and the cold clumps that were assembling into these first galaxies.

They were also not looking for the extremely brilliant rare objects - such as quasars and galaxies with very high rates of star formation - that had been seen up to now. Instead they concentrated on rather less dramatic, but much more common, galaxies that reionised the Universe and went on to turn into the bulk of the galaxies that we see around us now.

From one of the galaxies - given the label BDF 3299 - ALMA could pick up a faint but clear signal from the glowing carbon. However, this glow wasn't coming from the centre of the galaxy, but rather from one side.

Co-author Andrea Ferrara (Scuola Normale Superiore, Pisa, Italy) explains the significance of the new findings: "This is the most distant detection ever of this kind of emission from a 'normal' galaxy, seen less than one billion years after the Big Bang. It gives us the opportunity to watch the build-up of the first galaxies. For the first time we are seeing early galaxies not merely as tiny blobs, but as objects with internal structure!"

The astronomers think that the off-centre location of the glow is because the central clouds are being disrupted by the harsh environment created by the newly formed stars - both their intense radiation and the effects of supernova explosions - while the carbon glow is tracing fresh cold gas that is being accreted from the intergalactic medium.

By combining the new ALMA observations with computer simulations, it has been possible to understand in detail key processes occurring within the first galaxies. The effects of the radiation from stars, the survival of molecular clouds, the escape of ionising radiation and the complex structure of the interstellar medium can now be calculated and compared with observation. BDF 3299 is likely to be a typical example of the galaxies responsible for reionisation.

"We have been trying to understand the interstellar medium and the formation of the reionisation sources for many years. Finally to be able to test predictions and hypotheses on real data from ALMA is an exciting moment and opens up a new set of questions.This type of observation will clarify many of the thorny problems we have with the formation of the first stars and galaxies in the Universe," adds Andrea Ferrara.

Roberto Maiolino concludes: "This study would have simply been impossible without ALMA, as no other instrument could reach the sensitivity and spatial resolution required. Although this is one of the deepest ALMA observations so far it is still far from achieving its ultimate capabilities. In future ALMA will image the fine structure of primordial galaxies and trace in detail the build-up of the very first galaxies."

Notes:

[1] Neutral hydrogen gas very efficiently absorbs all the high-energy ultraviolet light emitted by young hot stars. Consequently, these stars are almost impossible to observe in the early Universe. At the same time, the absorbed ultraviolet light ionises the hydrogen, making it fully transparent. The hot stars are therefore carving transparent bubbles in the gas. Once all these bubbles merge to fill all of space, reionisation is complete and the Universe becomes transparent.

[2] They had redshifts ranging from 6.8 to 7.1.

[3] Astronomers are particularly interested in ionised carbon as this particular spectral line carries away most of the energy injected by stars and allows astronomers to trace the cold gas out of which stars form. Specifically, the team were looking for the emission from singly ionised carbon (known as [C II]). This radiation is emitted at a wavelength of 158 micrometres, and by the time it is stretched by the expansion of the Universe arrives at ALMA at just the right wavelength for it to be detected at a wavelength of about 1.3 millimetres.

This research was presented in a paper "The assembly of "normal" galaxies at z?7 probed by ALMA", by R. Maiolino et al., to appear in Monthly Notices of the Royal Astronomical Society on 22 July 2015.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
ESO
Stellar Chemistry, The Universe And All Within It






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





STELLAR CHEMISTRY
What happens when cosmic giants meet galactic dwarfs?
Crawley, Australia (SPX) Jul 14, 2015
When two different sized galaxies smash together, the larger galaxy stops the smaller one making new stars, according to a study of more than 20,000 merging galaxies. The research also found that when two galaxies of the same size collide, both galaxies produce stars at a much faster rate. Astrophysicist Luke Davies, from The University of Western Australia node of the International Centre ... read more


STELLAR CHEMISTRY
Ariane 5 orbits Star One C4 and MSG-4 on Arianespace's sixth flight in 2015

CRS-7 Investigation Update

EUTELSAT 8 West B satellite arrive in French Guiana

Failed strut caused SpaceX rocket blast: CEO Elon Musk

STELLAR CHEMISTRY
Opportunity heading into Marathon Valley

Antarctic Offers Insights Into Life on Mars

Earth and Mars Could Share A Life History

Celebrating 50 years of Martian imagery

STELLAR CHEMISTRY
Smithsonian embraces crowdfunding to preserve lunar spacesuit

NASA Sets Sights on Robot-Built Moon Colony

Technique may reveal the age of moon rocks during spaceflight

Russia to Land Space Vessel on Moon's Polar Region in 2019

STELLAR CHEMISTRY
New Horizons 'Captures' Two of Pluto's Smaller Moons

New Horizons Finds Second Mountain Range in Pluto's 'Heart'

10 year journey to Pluto achieves historic encounter

US spacecraft survives close encounter with Pluto

STELLAR CHEMISTRY
Astronomers bring a new hope to find 'Tatooine' planets

The Planetary Sweet Spot

ARIEL mission to reveal 'Brave New Worlds' among exoplanets

New Method Finds Best Candidates for Telescope Time

STELLAR CHEMISTRY
Engineers help NASA fine-tune new Space Launch System

String of cargo disasters puts pressure on space industry

US Space Command warns on overly fast Russian rocket engine phase out

Longest SLS Engine Test Yet Heats Up Summer Sky

STELLAR CHEMISTRY
Chinese earth station is for exclusively scientific and civilian purposes

Cooperation in satellite technology put Belgium, China to forefront

China set to bolster space, polar security

China's super "eye" to speed up space rendezvous

STELLAR CHEMISTRY
Japan space scientists hunting for new asteroid name

Football Shaped Asteroid Observed by Students at NAIC/NRAO

Robot lab Philae 'silent', says concerned ground control

Dawn Maneuvering to Third Science Orbit




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.