Re: Old Galaxies in the Young Universe: VLT Unravels New Population of Very Old Massive Galaxies (Forwarded)

From: Jim Greenfield (greenfield_7_at_hotmail.com)
Date: 08/06/04 

Date: 5 Aug 2004 20:45:39 -0700

Andrew Yee <ayee@nova.astro.utoronto.ca> wrote in message news:<iSfQc.35601$Vm1.776730@news20.bellglobal.com>...
> ESO Education and Public Relations Dept.
>
> ----------------------------------------------------------------------------
> Text with all links and the photos are available on the ESO Website at URL:
> http://www.eso.org/outreach/press-rel/pr-2004/pr-17-04.html
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>
> Contacts
>
> Andrea Cimatti
> INAF - Osservatorio Astrofisico di Arcetri
> Firenze, Italy
> Phone: +39-055-2752-297
> Mobile: +39-347-4686338
> Email: cimatti@arcetri.astro.it
>
> Alvio Renzini
> European Southern Observatory
> Garching, Germany
> Phone: +49 89 3200 6413
> Email: arenzini@eso.org
>
> ESO Press Release 17/04
>
> Under embargo until July 7, 19:00 CEST
>
> Old Galaxies in the Young Universe
>
> Very Large Telescope Unravels New Population of Very Old
> Massive Galaxies [1]
>
> Summary
>
> Current theories of the formation of galaxies are based
> on the hierarchical merging of smaller entities into
> larger and larger structures, starting from about the size of a
> stellar globular cluster and ending with clusters of galaxies.
> According to this scenario, it is assumed that no massive galaxies
> existed in the young universe.
>
> However, this view may now have to be revised. Using the multi-
> mode FORS2 instrument on the Very Large Telescope at Paranal,
> a team of Italian astronomers [2] have identified four remote
> galaxies, several times more massive than the Milky Way galaxy,
> or as massive as the heaviest galaxies in the present-day
> universe. Those galaxies must have formed when the Universe
> was only about 2,000 million years old, that is some 12,000 million
> years ago.
>
> The newly discovered objects may be members of a population of
> old massive galaxies undetected until now.
>
> The existence of such systems shows that the build-up of massive
> elliptical galaxies was much faster in the early Universe than
> expected from current theory.
>
> PR Photo 21a/04: Small Part of the K20 Field Showing the z=1.9
> Elliptical Galaxy (ACS/HST).
> PR Photo 21b/04: Averaged Spectrum of Old Galaxies
> (FORS2/VLT).
>
> Hierarchical merging
>
> Galaxies are like islands in the Universe, made of stars as well as
> dust and gas clouds. They come in different sizes and shapes.
> Astronomers generally distinguish between spiral galaxies -- like
> our own Milky Way, NGC 1232 or the famous Andromeda galaxy --
> and elliptical galaxies, the latter mostly containing old stars and
> having very little dust or gas. Some galaxies are intermediate
> between spirals and ellipticals and are referred to as lenticular or
> spheroidal galaxies.
>
> Galaxies are not only distinct in shape, they also vary in size: some
> may be as "light" as a stellar globular cluster in our Milky Way (i.e.
> they contain about the equivalent of a few million Suns) while
> others may be more massive than a million million Suns. Presently,
> more than half of the stars in the Universe are located in massive
> spheroidal galaxies.
>
> One of the main open questions of modern astrophysics and
> cosmology is how and when galaxies formed and evolved starting
> from the primordial gas that filled the early Universe. In the most
> popular current theory, galaxies in the local Universe are the result
> of a relatively slow process where small and less massive galaxies
> merge to gradually build up bigger and more massive galaxies. In
> this scenario, dubbed "hierarchical merging", the young Universe
> was populated by small galaxies with little mass, whereas the
> present Universe contains large, old and massive galaxies -- the
> very last to form in the final stage of a slow assembling process.
>
> If this scenario were true, then one should not be able to find
> massive elliptical galaxies in the young universe. Or, in other
> words, due to the finite speed of light, there should be no such
> massive galaxies very far from us. And indeed, until now no old
> elliptical galaxy was known beyond a radio-galaxy at redshift 1.55
> [3] that was discovered almost ten years ago.
>
> The K20 survey
>
> ESO PR Photo 21a/04 ESO PR Photo 21a/04
> Part of the K20 Field, centred on the z=1.9 galaxy (ACS/HST)
>
> Caption: ESO PR Photo 21a/04 shows a small region in the K20
> field surveyed by the astronomers. This region is centred on the
> newly discovered z=1.9 redshift galaxy. The image is based on
> frames acquired by the Advanced Camera for Surveys (ACS) on
> the Hubble Space Telescope in the framework of the GOODS
> Public HST Treasury Program (P.I. M. Giavalisco, STScI,
> Baltimore, USA). They show the real colours of the galaxies. The
> four old massive spheroidal galaxies discovered in this survey
> appear very red compared to the other faint galaxies. (Image
> courtesy of Piero Rosati and Bob Fosbury, ESO Garching).
>
> In order to better understand the formation process of galaxies and
> to verify if the hierarchical merging scenario is valid, a team of
> Italian and ESO astronomers [2] used ESO's Very Large Telescope
> as a "time machine" to do a search for very remote elliptical
> galaxies. However, this is not trivial. Distant elliptical galaxies, with
> their content of old and red stars, must be very faint objects indeed
> at optical wavelengths as the bulk of their light is redshifted into the
> infrared part of the spectrum. Remote elliptical galaxies are thus
> among the most difficult observational targets even for the largest
> telescopes; this is also why the 1.55 redshift record has persisted
> for so long.
>
> But this challenge did not stop the researchers. They obtained deep
> optical spectroscopy with the multi-mode FORS2 instrument on the
> VLT for a sample of 546 faint objects found in a sky area of 52
> arcmin2 (or about one tenth of the area of the Full Moon) known as
> the K20 field, and which partly overlaps with the GOODS-South
> area. Their perseverance paid off and they were rewarded by the
> discovery of four old, massive galaxies with redshifts between 1.6
> and 1.9. These galaxies are seen when the Universe was only
> about 25% of its present age of 13,700 million years.
>
> For one of the galaxies, the K20 team benefited also from the
> database of publicly available spectra in the GOODS-South area
> taken by the ESO/GOODS team.
>
> A new population of galaxies
>
> ESO PR Photo 21b/04 ESO PR Photo 21b/04
> Averaged Spectrum of Old Galaxies (FORS2/VLT).
>
> Caption: ESO PR Photo 21b/04 shows the averaged spectrum
> (blue) of the four newly discovered old massive galaxies
> compared to a set of template spectra. The bottom compares it
> with the spectrum of a star having a surface temperature of 7200
> degrees (green) and 6800 degrees (red), respectively. The upper
> graph makes a comparison with synthetic spectra of simulated
> simple stellar populations with ages of 500, 1100 and 3000 million
> years. This figure demonstrates that the newly found galaxies
> mostly contain old low-mass stars and must have formed between
> 1,000 and 2,000 million years earlier than the epoch at which they
> are now seen.
>
> The newly discovered galaxies are thus seen when the Universe
> was about 3,500 million years old, i.e. 10,000 million years ago. But
> from the spectra taken, it appears that these galaxies contain stars
> with ages between 1,000 and 2,000 million years. This implies that
> the galaxies must have formed accordingly earlier, and that they
> must have essentially completed their assembly at a moment when
> the Universe was only 1,500 to 2,500 million years old.
>
> The galaxies appear to have masses in excess of one hundred
> thousand million solar masses and they are therefore of sizes
> similar to the most massive galaxies in the present-day Universe.
> Complementary images taken within the GOODS ("The Great
> Observatories Origins Deep Survey") survey by the Hubble Space
> Telescope show that these galaxies have structures and shapes
> more or less identical to those of the present-day massive elliptical
> galaxies.
>
> The new observations have therefore revealed a new population of
> very old and massive galaxies.
>
> The existence of such massive and old spheroidal galaxies in the
> early Universe shows that the assembly of the present-day massive
> elliptical galaxies started much earlier and was much faster than
> predicted by the hierarchical merging theory. Says Andrea Cimatti
> (INAF, Firenze, Italy), leader of the team: "Our new study now
> raises fundamental questions about our understanding and
> knowledge of the processes that regulated the genesis and the
> evolutionary history of the Universe and its structures."
>
> More information
>
> The research presented in this Press Release appears in the July 8
> issue of the research journal Nature ("Old galaxies in the young
> Universe" by A. Cimatti et al.).
>
> Notes
>
> [1] This press release is coordinated with the Istituto Nazionale di
> Astrofisica (INAF). The Italian version is available at www.inaf.it .
>
> [2] The team is composed of Andrea Cimatti (INAF, Firenze),
> Emanuele Daddi and Alvio Renzini (ESO, Germany), Paolo
> Cassata, Eros Vanzella and Giulia Rodighiero (Universita di
> Padova, Italy), Lucia Pozzetti, Marco Mignoli and Giovanni
> Zamorani (INAF, Bologna), Stefano Cristiani (INAF, Trieste), and
> Adriano Fontana (INAF, Roma).
>
> [3] In astronomy, the redshift denotes the fraction by which the lines
> in the spectrum of an object are shifted towards longer
> wavelengths. The observed redshift of a remote galaxy provides an
> estimate of its distance.
>
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More very bad news for GR and SR.
 Former claims that the "fact" that the very distant galaxies were
young has long been crowed as strong evidence for the Big Bang. Now
that is in ruins, by these observations which show the universe is
pretty much the same mix throughout. By association, GR/SR is
terminal, as "proof" of BB was a mainstay of the theory(s).

Jim G

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