MKT Library

Saturday is Sexy… Sunday is Movies Night

Telescope Detects Oldest And Most Distant Known Galaxy

May 6, 2015 | by Stephen Luntz

photo credit: NASA, ESA, P. Oesch and I. Momcheva (Yale University), and the 3D-HST and HUDF09/XDF teams. EGS-zs8-1 is the oldest galaxy whose age has been precisely measured.

photo credit: NASA, ESA, P. Oesch and I. Momcheva (Yale University), and the 3D-HST and HUDF09/XDF teams. EGS-zs8-1 is the oldest galaxy whose age has been precisely measured.

The most distant, and therefore oldest, galaxy ever seen has had its distance confirmed. The discovery gives us our best opportunity yet to learn about galaxy building in the early universe.

Images from the Hubble and Spitzer space telescopes revealed Galaxy EGS-zs8-1 as being enormously redshifted, and therefore very, very distant. However, to confirm it as a record breaker required a larger, ground based instrument. This has now been done using one of Keck Observatory’s 10-meter telescopes, with the results published in The Astrophysical Journal.

Keck’s Multi-Object Spectrometer for Infra-Red Exploration (MOSFIRE) measured EGS-zs8-1 at a z of 7.73, which translates to a distance of 13.0 billion light years. With the universe 13.713.8 billion years old, this means we are seeing back to when it was just 5% of its current age. Although this is the most distant confirmed galaxy, it does not quite match the Gamma Ray Burst GRB 090423 whose red shift was 8.2. There have been several observations of galaxies that at their maximum could be further away, but whose measurements have large margins for error.

The remarkable thing about EGS-zs8-1 is how evolved it was for the time. “It has already built more than 15% of the mass of our own Milky Way today,” said lead author Dr Pascal Oesch of Yale. “But it had only 670 million years to do so. The universe was still very young then.” At the point where we see it, EGS-zs8-1 is still in rapid star formation mode, 80 times the stately rate of the Milky Way.

The period where we see EGS-zs8-1 was an important one for the universe during what is known as the epoch of reionization. The light of the first stars split neutral hydrogen into an ionized plasma which absorbed much of the light, and making the universe opaque. As time went on the universe grew to the point where matter was sufficiently spread that light had a better chance of escaping without being absorbed by this plasma, giving us a chance to see it.

MOSFIRE, which started observations in 2012, enables astronomers to measure the redshift of several galaxies at once. The researchers also found two other galaxies they describe as “very similar sources” with red shifts of 7.21 and 7.51, indicating that EGS-zs8-1 is part of a continuum, rather than a strange outlier. The observations were clear enough to provide support for the theory that the first stars were massive giants, many larger than anything that exists today.

The paper notes that the discovery bodes well for measuring the distances to very early galaxies with the James Webb Space Telescope when it launches in 2018.

Source: IFLS

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s


This entry was posted on May 12, 2015 by in Astronomy, Space and tagged , , , , , .

Enter your email address to follow this blog and receive notifications of new posts by email.

Join 301 other followers

Follow MKT Library on

A great site

Caz the Comic Strip

Cartoon strip about Caz and her family

Don't just read the news, understand it!

Coffee Conversations

Official blog of Zurairi AR: Journo, researcher, humanist, father.


Read it! 📖 Spark it! ✨


Everything on Mesopotamia, Modern Iraq, and Global Art

The Hitchhiking Postdoc

A guide to chemical biology and to the mind of a hitchhiking postdoc


Startup and Technology News

Scrub Physics

Writings on science, technology, economics, and rationality



Snapzu Science

We blog the best science & space posts as submitted and voted on by the Snapzu community! Invites available!

ScienceQ publishing Group

Blog of scienceQ publishing Group

Duke Energy Nuclear Information Center

A glimpse into the world of nuclear energy


Science - Simplified


My encounters with Cosmology

%d bloggers like this: