Ancient Galaxies twice the size of the Milky Way

In summary, the galaxies observed at a relativity short time after the BB are still consistent with the BB theory. There are many Cosmologists who support the theory of a Universe from nothing to explain how the U began.
  • #1
Tanelorn
888
15
I saw this news about galaxies twice the size of the milky way observed a relativity short time after the BB and wondered if this is still consistent with the BB theory or its timing?

http://news.yahoo.com/ancient-monster-galaxies-scientists-perplexed-122353576.html
I also wanted to ask if there are many Cosmologists who support the theory of a Universe from nothing to explain how the U began?
 
Space news on Phys.org
  • #2
It's always going to be hard to say, because the physics of galaxy formation are extremely complicated, and because there's quite a lot of natural variation in local matter density.
 
  • #3
Here is the technical paper the the popular journalism refers to:
http://arxiv.org/abs/1505.05721
Spitzer bright, UltraVISTA faint sources in COSMOS: the contribution to the overall population of massive galaxies at z=3-7
K. I. Caputi, O. Ilbert, C. Laigle, H. J. McCracken, O. Le Fevre, J. Fynbo, B. Milvang-Jensen, P. Capak, M. Salvato, Y. Taniguchi
(Submitted on 21 May 2015)
We have analysed a sample of 574 Spitzer 4.5 micron-selected galaxies with [4.5]<23 and Ks_auto>24 (AB) over the UltraVISTA ultra-deep COSMOS field. Our aim is to investigate whether these mid-IR bright, near-IR faint sources contribute significantly to the overall population of massive galaxies at redshifts z>=3. By performing a spectral energy distribution (SED) analysis using up to 30 photometric bands, we have determined that the redshift distribution of our sample peaks at redshifts z~2.5-3.0, and ~32% of the galaxies lie at z>=3. We have studied the contribution of these sources to the galaxy stellar mass function (GSMF) at high redshifts. We found that the [4.5]<23, Ks_auto>24 galaxies produce a negligible change to the GSMF previously determined for Ks_auto<24 sources at 3=<z<4, but their contribution is more important at 4=<z<5, accounting for >~50% of the galaxies with stellar masses Mst>~6 x 10^10 Msun. We also constrained the GSMF at the highest-mass end (Mst>~2 x 10^11 Msun) at z>=5. From their presence at 5=<z<6, and virtual absence at higher redshifts, we can pinpoint quite precisely the moment of appearance of the first most massive galaxies as taking place in the ~0.2 Gyr of elapsed time between z~6 and z~5. Alternatively, if very massive galaxies existed earlier in cosmic time, they should have been significantly dust-obscured to lie beyond the detection limits of current, large-area, deep near-IR surveys.
18 pages, 15 figures, 4 tables. Updated to match version in press at the ApJ

You can see Karina Caputi and Henry McCracken ( both quoted in the Yahoo account) listed among the authors.
You can see the stellar mass estimates 60 billion and 200 billion solar masses. You can also see the redshift z estimate of between 5 and 6.
How one compares this to the Milky Way depends on how one rates the constituents of our galaxy: how much is stars, gas, dust, etc.
At issue is the "GSMF" the galaxy stellar mass function. How one translates the observed brightness of a galaxy into an estimate of the overall mass of stars in it. Results like this may not be earth-shaking but they might eventually result in some adjustment of the way the GSMF is calculated for galaxies with redshifts like z = 5 and z = 6.
 
  • #5
wolram said:
It is amazing astronomers keep finding galaxies closer and closer to the big bang

But still not very close, if you think in terms of redshift, which is a measure of how much the universe has expanded since the light was emitted. The largest redshift on the list is z = 8.68, which corresponds to the universe expanding by a factor of 1 + z, or almost 10, since that light was emitted. But the CMB is at a redshift of z = 1000, so the universe expanded by a factor of about 100 between the CMB being emitted and the oldest galaxy on the list emitting the light we now see.
 

Related to Ancient Galaxies twice the size of the Milky Way

1. What is the significance of finding ancient galaxies twice the size of the Milky Way?

The discovery of ancient galaxies twice the size of the Milky Way is significant because it challenges our understanding of galaxy formation and evolution. These large and distant galaxies are thought to have formed in the early universe, providing valuable insights into the early stages of galaxy formation.

2. How do scientists determine the size of these ancient galaxies?

Scientists use a variety of methods to determine the size of ancient galaxies, including analyzing their brightness and distance. They also use advanced telescopes such as the Hubble Space Telescope to observe and measure the size and structure of these galaxies.

3. What can we learn from studying ancient galaxies?

Studying ancient galaxies can provide us with valuable information about the history of the universe and how galaxies have evolved over time. It can also give us insights into the processes that govern galaxy formation and the growth of supermassive black holes.

4. How far away are these ancient galaxies?

These ancient galaxies are located billions of light-years away from Earth. This means that the light we see from these galaxies has taken billions of years to reach us, allowing us to look back in time and see how they appeared in the early universe.

5. Are there other ancient galaxies that are even larger than the Milky Way?

Yes, there are other ancient galaxies that are even larger than the Milky Way. In fact, some of these galaxies are estimated to be up to ten times larger than our own galaxy. This further supports the idea that galaxy formation and evolution were much different in the early universe compared to what we see today.

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