SETI The Atacama Large Millimeter Array (ALMA)


Larry Klaes (lklaes@bbn.com)
Fri, 11 Jun 1999 13:29:20 -0400


>From: owner-esonews@web3.hq.eso.org >Date: Thu, 10 Jun 1999 22:30:58 +0200 (MET DST) >To: Subscribers@cam-smtp1.bbn.com, to@cam-smtp1.bbn.com, > ESO-NEWS@cam-smtp1.bbn.com >Sender: owner-esonews@web3.hq.eso.org >Reply-To: esonews@web3.hq.eso.org > >From: ESO Education and Public Relations Dept. > >Date: Thursday, June 10, 1999 > >Subject: ESO Press Release on the ALMA project with photos and a video clip > >---------------------------------------------------------------------------- > >Text with all links is available on the ESO Website at URL: > >http://www.eso.org/outreach/press-rel/pr-1999/pr-09-99.html > >---------------------------------------------------------------------------- > >Dear subscribers, > >in addition to the joint NSF-ESO Press Release about ALMA, sent to you >in an earlier email, ESO is releasing a series of related photos and a >video clip that illustrate the new project. The original URL is: > >http://www.eso.org/outreach/press-rel/pr-1999/pr-09-99.html > >We would also like to draw your attention to the recent publication on >the web of information about the major meeting in March 2000 on >Astronomical Telescopes and Instruments, organised by SPIE and >cosponsored by ESO, at URL: http://www.spie.org/info/as/. > >Kind regards, > >ESO EPR Dept. > >---------------------------------------------------------------------------- > Information from the European Southern Observatory > > ESO Press Release 09/99 [1] > > 10 June 1999 [ESO Logo] > > For immediate release > ------------------------------------------------------------------------ > >The Atacama Large Millimeter Array (ALMA) > > [ESO PR Photo 24a/99] ESO PR Photo Caption to ESO PR Photo 24a/99: > 24a/99 Artist's impression of ALMA. Up to > 64 12-m antennas will be placed on > [Preview - JPEG: 400 x 302 pix - the Chajnantor site, a high plateau > 97k] at an altitude of about 5000 meters > (15,000 ft) amongst the Andean > [Normal - JPEG: 800 x 604 pix - mountains in Chile. Further photos > 336k] and a video clip are available at > the end of this Press Release. > [High-Res - JPEG: 2500 x 1887 pix - > 1.6M] > >The Atacama Large Millimeter Array (ALMA) is the new name [2] for a giant >millimeter-wavelength telescope project. As described in the accompanying >joint press release by ESO and the U.S. National Science Foundation, the >present design and development phase is now a Europe-U.S. collaboration, and >may soon include Japan. ALMA may become the largest ground-based astronomy >project of the next decade after VLT/VLTI, and one of the major new >facilities for world astronomy. ALMA will make it possible to study the >origins of galaxies, stars and planets. > >As presently envisaged, ALMA will be comprised of up to 64 12-meter diameter >antennas distributed over an area 10 km across. ESO PR Photo 24a/99 shows an >artist's concept of a portion of the array in a compact configuration. ESO >PR Video Clip 03/99 illustrates how all the antennas will move in unison to >point to a single astronomical object and follow it as it traverses the sky. >In this way the combined telescope will produce astronomical images of great >sharpness and sensitivity [3]. > >An exceptional site > >For such observations to be possible the atmosphere above the telescope must >be transparent at millimeter and submillimeter wavelengths. This requires a >site that is high and dry, and a high plateau in the Atacama desert of >Chile, probably the world's driest, is ideal - the next best thing to outer >space for these observations. > >ESO PR Photo 24b/99 shows the location of the chosen site at Chajnantor, at >5000 meters altitude and 60 kilometers east of the village of San Pedro de >Atacama, as seen from the Space Shuttle during a servicing mission of the >Hubble Space Telescope. ESO PR Photo 24c/99 and ESO PR Photo 24d/99 show a >satellite image of the immediate vicinity and the site marked on a map of >northern Chile. ALMA will be the highest continuously operated observatory >in the world. The stark nature of this extreme site is well illustrated by >the panoramic view in ESO PR Photo 24e/99. > >High sensitivity and sharp images > >ALMA will be extremely sensitive to radiation at milllimeter and >submillimeter wavelengths. The large number of antennas gives a total >collecting area of over 7000 square meters, larger than a football field. At >the same time, the shape of the surface of each antenna must be extremely >precise under all conditions; the overall accuracy over the entire 12-m >diameter must be better than 0.025 millimeters (25 micron), or one-third of the >diameter of a human hair. The combination of large collecting area and high >precision results in extremely high sensitivity to faint cosmic signals. > >The telescope must also be able to resolve the fine details of the objects >it detects. In order to do this at millimeter wavelengths the effective >diameter of the overall telescope must be very large - about 10 km. As it is >impossible to build a single antenna with this diameter, an array of >antennas is used instead, with the outermost antennas being 10 km apart. By >combining the signals from all antennas together in a large central >computer, it is possible to synthesize the effect of a single dish 10 km >across. The resulting angular resolution is about 10 milli-arcseconds, less >than one-thousandth the angular size of Saturn. > >Exciting research perspectives > >The scientific case for this revolutionary telescope is overwhelming. ALMA >will make it possible to witness the formation of the earliest and most >distant galaxies. It will also look deep into the dust-obscured regions >where stars are born, to examine the details of star and planet formation. >But ALMA will go far beyond these main science drivers, and will have a >major impact on virtually all areas of astronomy. It will be a >millimeter-wave counterpart to the most powerful optical/infrared telescopes >such as ESO's Very Large Telescope (VLT) and the Hubble Space Telescope, >with the additional advantage of being unhindered by cosmic dust opacity. > >The first galaxies in the Universe are expected to become rapidly enshrouded >in the dust produced by the first stars. The dust can dim the galaxies at >optical wavelengths, but the same dust radiates brightly at longer >wavelengths. In addition, the expansion of the Universe causes the radiation >from distant galaxies to be shifted to longer wavelengths. For both reasons, >the earliest galaxies at the epoch of first light can be found with ALMA, >and the subsequent evolution of galaxies can be mapped over cosmic time. > >ALMA will be of great importance for our understanding of the origins of >stars and planetary systems. Stellar nurseries are completely obscured at >optical wavelengths by dense "cocoons" of dust and gas, but ALMA can probe >deep into these regions and study the fundamental processes by which stars >are assembled. Moreover, it can observe the major reservoirs of biogenic >elements (carbon, oxygen, nitrogen) and follow their incorporation into new >planetary systems. A particularly exciting prospect for ALMA is to use its >exceptionally sharp images to obtain evidence for planet formation by the >presence of gaps in dusty disks around young stars, cleared by large bodies >coalescing around the stars. > >Equally fundamental are observations of the dying gasps of stars at the >other end of the stellar lifecycle, when they are often surrounded by shells >of molecules and dust enriched in heavy elements produced by the nuclear >fires now slowly dying. > >ALMA will offer exciting new views of our solar system. Studies of the >molecular content of planetary atmospheres with ALMA's high resolving power >will provide detailed weather maps of Mars, Jupiter, and the other planets >and even their satellites. > >Studies of comets with ALMA will be particularly interesting. The molecular >ices of these visitors from the outer reaches of the solar system have a >composition that is preserved from ages when the solar system was forming. >They evaporate when the comet comes close to the sun, and studies of the >resulting gases with ALMA will allow accurate analysis of the chemistry of >the presolar nebula. > >The road ahead > >The three-year design and development phase of the project is now underway >as a collaboration between Europe and the U.S., and Japan may also join in >this effort. Assuming the construction phase begins about two years from >now, limited operations of the array may begin in 2005 and the full array >may become operational by 2009. > >Notes > >[1] Press Releases about this event are also issued by some of the other >organisations participating in this project. > >[2] "ALMA" means "soul" in Spanish. > >[3] Additional information about ALMA is available on the web: > > * Articles in the ESO Messenger - "The Large Southern Array" (March > 1998), "European Site Testing at Chajnantor" (December 1998) and "The > ALMA Project" (June 1999), cf. > http://www.eso.org/gen-fac/pubs/messenger/ > * ALMA website at ESO at http://www.eso.org/projects/alma/ > * ALMA website at the U.S. National Radio Astronomy Observatory (NRAO) at > http://www.mma.nrao.edu/ > > ------------------------------------------------------------------------ > >ALMA/Chajnantor Video Clip and Photos > > [ESO PR Video Clip 03/99 [MPEG-version] About ESO Video Clip 03/99: > This video clip about the > ALMA project contains two > Clip 03/99 (2450 frames/1:38 min) sequences. The first shows > [MPEG Video; 160x120 pix; 2.1Mb] a panoramic scan of the > [MPEG Video; 320x240 pix; 10.0Mb] Chajnantor plain from > [RealMedia; streaming; 700k] approx. north-east to > [RealMedia; streaming; 2.3M] north-west. The Chajnantor > mountain passes through the > field-of-view and the > perfect cone of the > Licancabur volcano (5900 m) > on the Bolivian border is > seen at the end (compare > also with ESO PR 24e/99 > below. The second is a > 52-sec animation with a > change of viewing > perspective of the array > and during which the > antennas move in unison. > For convenience, the clip > is available in four > versions: two MPEG files of > different sizes and two > streamer-versions of > different quality that > require RealPlayer > software. There is no > audio. > > > > [ESO PR Photo 24b/99] ESO PR Photo 24b/99 Caption to ESO PR Photo > 24b/99: View of Northern > [Preview - JPEG: Chile, as seen from the > 400 x 446 pix - 184k] NASA Space Shuttle during a > servicing mission to the > [Normal - JPEG: Hubble Space Telescope > 800 x 892 pix - 588k] (partly visible to the > left). The Atacama Desert, > [High-Res - JPEG: site of the ESO VLT at > 3000 x 3345 pix - 5.4M] Paranal Observatory and the > proposed location for ALMA > at Chajnantor, is seen from > North (foreground) to > South. The two sites are > only a few hundred km > distant from each other. > Few clouds are seen in this > extremely dry area, due to > the influence of the cold > Humboldt Stream along the > Chilean Pacific coast > (right) and the high Andes > mountains (left) that act > as a barrier. Photo > courtesy ESA astronaut > Claude Nicollier. > > > > [ESO PR Photo 24c/99] ESO PR Photo 24c/99 Caption to ESO PR Photo > 24c/99: This satellite > [Preview - JPEG: image of the Chajnantor > 400 x 318 pix - 212k] area was produced in 1998 > at Cornell University > [Normal - JPEG: (USA), by Jennifer Yu, > 800 x 635 pix - 700k] Jeremy Darling and Riccardo > Giovanelli, using the > [High-Res - JPEG: Thematic Mapper data base > 3000 x 2382 pix - 5.9M] maintained at the Geology > Department laboratory > directed by Bryan Isacks. > It is a composite of three > exposures in spectral bands > at 1.6 5m (rendered as > red), 1.0 5m (green) and > 0.5 5m (blue). The > horizontal resolution of > the false-colour image is > about 30 meters. North is > at the top of the photo. > > > > [ESO PR Photo 24d/99] ESO PR Photo 24d/99 Caption to ESO PR Photo > 24d/99: Geographical map > [Preview - JPEG: with the sites of the VLT > 400 x 381 pix - 108k] and ALMA indicated. > > [Normal - JPEG: > 800 x 762 pix - 240k] > > [High-Res - JPEG: > 2300 x 2191 pix - 984k] > > > > [ESO PR Photo 24e/99] ESO PR Photo 24e/99 Caption to ESO PR Photo > 24e/99: Panoramic view of > [Preview - JPEG: the proposed site for ALMA > 400 x 238 pix - 93k] at Chajnantor. This > high-altitude plain > [Normal - JPEG: (elevation 5000 m) in the > 800 x 475 pix - 279k] Chilean Andes mountains is > an ideal site for ALMA. In > [High-Res - JPEG: this view towards the > 2862 x 1701 pix - 4.2M] north, the Chajnantor > mountain (5600 m) is in the > foreground, left of the > centre. The perfect cone of > the Licancabur volcano > (5900 m) on the Bolivian > border is in the background > further to the left. This > image is a wide-angle > composite (1400 x 700) of > three photos (Hasselblad > 6x6 with SWC 1:4.5/38 mm > Biogon), obtained in > December 1998. > ------------------------------------------------------------------------ > >How to obtain ESO Press Information > >ESO Press Information is made available on the World-Wide Web (URL: >http://www.eso.org/outreach/press-rel/). ESO Press Photos may be reproduced, >if credit is given to the European Southern Observatory. > > > ------------------------------------------------------------------------ > >



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