766,121 research outputs found
Italian Science Case for ALMA Band 2+3
The Premiale Project "Science and Technology in Italy for the upgraded ALMA
Observatory - iALMA" has the goal of strengthening the scientific,
technological and industrial Italian contribution to the Atacama Large
Millimeter/submillimeter Array (ALMA), the largest ground based international
infrastructure for the study of the Universe in the microwave. One of the main
objectives of the Science Working Group (SWG) inside iALMA, the Work Package 1,
is to develop the Italian contribution to the Science Case for the ALMA Band 2
or Band 2+3 receiver. ALMA Band 2 receiver spans from ~67 GHz (bounded by an
opaque line complex of ozone lines) up to 90 GHz which overlaps with the lower
frequency end of ALMA Band 3. Receiver technology has advanced since the
original definition of the ALMA frequency bands. It is now feasible to produce
a single receiver which could cover the whole frequency range from 67 GHz to
116 GHz, encompassing Band 2 and Band 3 in a single receiver cartridge, a so
called Band 2+3 system. In addition, upgrades of the ALMA system are now
foreseen that should double the bandwidth to 16 GHz. The science drivers
discussed below therefore also discuss the advantages of these two enhancements
over the originally foreseen Band 2 system.Comment: 43 pages, 21 figure
The ISM at high redshifts: ALMA results and a look to the future
ALMA is revolutionizing the way we study and understand the astrophysics of
galaxies, both as a whole and individually. By exploiting its unique
sensitivity and resolution to make spatially and spectrally resolved images of
the gas and dust in the interstellar medium (ISM), ALMA can reveal new
information about the relationship between stars and gas, during and between
galaxies' cycles of star formation and AGN fueling. However, this can only be
done for a modest number of targets, and thus works in the context of large
samples drawn from other surveys, while providing parallel deep imaging in
small fields around. Recent ALMA highlights are reviewed, and some areas where
ALMA will potentially make great contributions in future are discussed.Comment: 8 pages, Review contribution to the Third Year ALMA conference,
Tokyo, December 201
Origins of the ALMA Project in the scientific visions of the North American, European, and Japanese astronomical communities
ALMA is a worldwide project, the synthesis of early visions of astronomers in
its three partner communities, Europe, North America, and Japan. The evolution
of these concepts and their eventual merger into ALMA are discussed, setting
the background for the papers which follow on the scientific requirements and
expected performance of ALMA for extra-galactic, galactic, and solar system
research.Comment: 4 pages, including 1 figure; to appear in ESA SP-577, Proceedings of
the conference "Dusty and Molecular Universe - A prelude to HERSCHEL AND
ALMA", October 25-27, 2004, Pari
European ALMA operations: the interaction with and support to the users
The Atacama Large Millimetre/submillimetre Array (ALMA) is one of the largest
and most complicated observatories ever built. Constructing and operating an
observatory at high altitude (5000m) in a cost effective and safe manner, with
minimal effect on the environment creates interesting challenges. Since the
array will have to adapt quickly to prevailing weather conditions, ALMA will be
operated exclusively in service mode. By the time of full science operations,
the fundamental ALMA data product shall be calibrated, deconvolved data cubes
and images, but raw data and data reduction software will be made available to
users as well. User support is provided by the ALMA Regional Centres (ARCs)
located in Europe, North America and Japan. These ARCs constitute the interface
between the user community and the ALMA observatory in Chile. For European
users the European ARC is being set up as a cluster of nodes located throughout
Europe, with the main centre at the ESO Headquarters in Garching. The main
centre serves as the access portal and in synergy with the distributed network
of ARC nodes, the main aim of the ARC is to optimize the ALMA science output
and to fully exploit this unique and powerful facility. The aim of this article
is to introduce the process of proposing for observing time, subsequent
execution of the observations, obtaining and processing of the data in the ALMA
epoch. The complete end-to-end process of the ALMA data flow from the proposal
submission to the data delivery is described.Comment: 7 pages, three figure
Detecting the Most Distant (z>7) Objects with ALMA
Detecting and studying objects at the highest redshifts, out to the end of
Cosmic Reionization at z>7, is clearly a key science goal of ALMA. ALMA will in
principle be able to detect objects in this redshift range both from high-J
(J>7) CO transitions and emission from ionized carbon, [CII], which is one of
the main cooling lines of the ISM. ALMA will even be able to resolve this
emission for individual targets, which will be one of the few ways to determine
dynamical masses for systems in the Epoch of Reionization. We discuss some of
the current problems regarding the detection and characterization of objects at
high redshifts and how ALMA will eliminate most (but not all) of them.Comment: to appear in Astrophysics and Space Science, "Science with ALMA: a
new era for Astrophysics", ed. R. Bachille
ALMA detection of dark chromospheric holes in the quiet Sun
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations
of a quiet-Sun region at a wavelength of 3 mm, obtained during the first solar
ALMA cycle on April 27, 2017, and compare them with available chromospheric
observations in the UV and visible as well as with photospheric magnetograms.
ALMA images clearly reveal the presence of distinct particularly dark/cool
areas in the millimeter maps having temperatures as low as 60% of the normal
quiet Sun at 3 mm, which are not seen in the other data. We speculate that ALMA
is sensing cool chromospheric gas, whose presence had earlier been inferred
from infrared CO spectra.Comment: 9 pages, 3 figures, accepted for publication in ApJ
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