Using data from the Hubble Space telescope, astronomers show that galaxies had “mature” shapes 11.5 billion years ago.
Studying the evolution and anatomy of galaxies using the Hubble Space Telescope, an international team of astronomers led by doctoral candidate BoMee Lee and her advisor, professor Mauro Giavalisco, have established that mature-looking galaxies existed much earlier than previously known, when the universe was only about 2.5 billion years old, or 11.5 billion years ago. “Finding them this far back in time is a significant discovery,” says lead author Lee.
The team used two cameras, Wide Field Camera 3 (WFC3), and Advanced Camera for Surveys (ACS), plus observations from the Hubble’s Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), the largest project in the scope’s history with 902 assigned orbits of observing time, to explore the shapes and colors of distant galaxies over the last 80 percent of the Universe’s history. Results appear in the current online issue of The Astrophysical Journal.
Lee points out that the huge CANDELS dataset allowed her team to analyze a larger number of these galaxies, a total 1,671, than ever before, consistently and in detail. “The significant resolution and sensitivity of WFC3 was a great resource for us to use in order to consistently study ancient galaxies in the early Universe,” says Lee.
She and colleagues confirm for an earlier period than ever before that the shapes and colors of these extremely distant young galaxies fit the visual classification system introduced in 1926 by Edwin Hubble and known as the Hubble Sequence. It classifies galaxies into two main groups: Ellipticals and spirals, with lenticular galaxies as a transitional group. The system is based on their ability to form stars, which in turn determines their colors, shape and size.
Why modern galaxies are divided into these two main types and what caused this difference is a key question of cosmology, says Giavalisco. “Another piece of the puzzle is that we still do not know why today ‘red and dead’ elliptical galaxies are old and unable to form stars, while spirals, like our own Milky Way, keep forming new stars. This is not just a classification scheme, it corresponds to a profound difference in the galaxies’ physical properties and how they were formed.”
Lee adds, “This was a key question: When, and over what timescale did the Hubble Sequence form? To answer this, you need to peer at distant galaxies and compare them to their closer relatives, to see if they too can be described in the same way. The Hubble Sequence underpins a lot of what we know about how galaxies form and evolve. It turns out that we could show this sequence was already in place as early as 11.5 billion years ago.”
Galaxies as massive as the Milky Way are relatively rare in the young Universe. This scarcity prevented previous studies from gathering a large enough sample of mature galaxies to properly describe their characteristics. Galaxies at these early times appear to be mostly irregular systems with no clearly defined morphology. There are blue star-forming galaxies that sometimes show structures such as discs, bulges and messy clumps, as well as red galaxies with little or no star formation. Until now, nobody knew if the red and blue colors were related to galaxy morphology, the authors note.
There was previous evidence that the Hubble Sequence holds true as far back as around 8 billion years ago, the authors point out, but their new observations push a further 2.5 billion years back in cosmic time, covering 80 percent of the history of the Universe.
Previous studies had also reached into this epoch to study lower-mass galaxies, but none had conclusively looked at large, mature galaxies like the Milky Way. Lee and colleagues’ new observations confirm that all galaxies this far back, big and small, already fit into the sequence a mere 2.5 billion years after the Big Bang.
“Clearly, the Hubble Sequence formed very quickly in the history of the cosmos, it was not a slow process,” adds Giavalisco. “Now we have to go back to theory and try to figure out how and why.”
Besides Lee, Giavalisco, and Astronomy research assistant C.C. Williams, with van der Wel in Heidelberg, the team includes astronomers from the University of California, the Space Telescope Science Institute, the University of Kentucky, the University of Nottingham, U.K., the Max Planck Institute for Extraterrestrial Physics, The Hebrew University, Israel, National Optical Astronomy Observatory, Tucson, and the University of Michigan.
This work was funded by NASA through a grant administered by the Space Telescope Science Institute, which operates the Hubble Space Telescope. The telescope is a project of international cooperation between the European Space Agency and NASA.
Publication: Bomee Lee, et al., “CANDELS: The correlation between galaxy morphology and star formation activity at z~2,” 2013, ApJ, 774, 47; doi:10.1088/0004-637X/774/1/47
PDF Copy of the Study: CANDELS: The correlation between galaxy morphology and star formation activity at z~2
As explained in my web site there are ancient galaxies discovered at 13.4 billions LY ago by HST in 2012… this means that Universe is uniform in space and time without origin.. and No big bang
[Another piece of the puzzle is that we still do not know why today ‘red and dead’ elliptical galaxies are old and unable to form stars, while spirals, like our own Milky Way, keep forming new stars.]
THE UNIVERSE GROWS FROM THE OUTSIDE IN – via the expansion of time (time meaning Expansionary energy, energy being the “thing in itself” and the sole content of all that exists.
Energy forms from what we refer to as “empty space”. Empty space in reality is non-overlapping energy, where both “content” and “the action of this content” are the two resulting properties of Time’s expansion.
Matter is simply “compressed” or overlaid “time planes”. A “time plane” is where outwards expansion overcomes the immediate shell of holistic expansion (meaning expanding in all directions both inwards and outwards), and changes from an elliptical entity into a flattened closer to 2 dimensional entity. To picture this imagine a fertilised egg in a closed box – due to internal growth the egg hatches and breaks the shell, a chick emerges, holds the chick form for a while then dies. Once dead, over time the form of the ex-chick collapses, decays and flattens and spreads over the bottom of the box.
The electromagnetic spectrum is a result of this flattening effect, but so are spiral galaxies. It is all about the equalisation of the internal and external pressures caused by expansion. The flattening solidifies resistance into a smaller “causal” spatial territory and in doing so allows for a lesser path of resistance in the spherical energy territory that this area of existence once occupied, but a greater 2 dimensional resistance in the area now occupied. This allows flattened time planes to be closer together both as a pack of cards (stacked) and a house of cards (situated at right angles to another plane and thus divided into + or – sides), and various combinations of this casual energy-least resistance interconnected become what we see as matter.
Elliptical galaxies with their spherical shape, push newly forming matter away, as the path of least resistance is lesser further away from the outwards push of new matter being created within the sphere. They simply do not attract enough new material to be called “live” (live meaning growing).
Younger spiral galaxies with the circular flow of their star arms include channels of lesser resistance between, and more inwards directional expansion from, each of the arms. Also they are like harvesters drawing matter into them and pushing it towards the centre as the arms spin. This keeps the stars alive as the galaxy will continue to grow until it matures and “gravity” (the path of least resistance) creates an elliptical galaxy.
There cannot be a big bang at the level of The Totality, but there can and are be miniscule-to-big bangs within spherical segments of what already exists. An atom exploding is a small scale big bang. The point is though is that any big bang of any size, will explode into and be reformed by, and merge with, already existing existence.
As co-Principal Investigator of the CANDELS survey, I’d like to clear up a misimpression that one might get from looking at the montage of galaxies — — unfortunately there was a bit more “artistic license” taken with the image for this press release than there should have been, and we failed to put the brakes on before the press release went out. The pictures of the galaxies marked as “11 billion years” are not at the right redshift (redshift z=2.5 corresponds to a lookback time of 11 billion years). If you would like to see what the Hubble images of such galaxies like, head on over to the CANDELS blog http://candels-collaboration.blogspot.com/2013/08/were-galaxies-really-mature-11-billion.html.
The basic conclusion of the papers on which this story was based is that we can start to see the dichotomy between star-forming galaxies being “disk like” and non-star-forming galaxies being “spheroid like” already being set into place 11 billion years ago. We wish we could see galaxies 11 billion years ago with the sort of clarity shown on the press-release image, but unfortunately even with Hubble we can’t see that level of detail…and to the extent that we can distinguish detail they look (a) smaller and (b) generally bluer, and (c) less well-ordered than present-day galaxies.
Thanks for the update and great research!