273 research outputs found
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
American Prodigal: White Church, Black Church, and the Feast of Social Justice
Editor\u27s Note: Dr. Vanden Bout presented this paper at the Prodigal Love of God Conference, in celebration of the 400th anniversary of the Canons of Dort, April 2019, sponsored by Dordt University and co-sponsored by the Lilly Fellowship Program, as a regional conference
Continuum Observations at 350 Microns of High-Redshift Molecular Emission Line Galaxies
We report observations of 15 high redshift (z = 1-5) galaxies at 350 microns
using the Caltech Submillimeter Observatory and SHARC-II array detector.
Emission was detected from eight galaxies, for which far-infrared luminosities,
star formation rates, total dust masses, and minimum source size estimates are
derived. These galaxies have star formation rates and star formation
efficiencies comparable to other high redshift molecular emission line
galaxies. The results are used to test the idea that star formation in these
galaxies occurs in a large number of basic units, the units being similar to
star-forming clumps in the Milky Way. The luminosity of these extreme galaxies
can be reproduced in a simple model with (0.9-30) *10^6 dense clumps, each with
a luminosity of 5 *10^5 Lsun, the mean value for such clumps in the Milky Way.
Radiative transfer models of such clumps can provide reasonable matches to the
overall SEDs of the galaxies. They indicate that the individual clumps are
quite opaque in the far-infrared. Luminosity to mass ratios vary over two
orders of magnitude, correlating strongly with the dust temperature derived
from simple fits to the SED. The gas masses derived from the dust modeling are
in remarkable agreement with those from CO luminosities, suggesting that the
assumptions going into both calculations are reasonable.Comment: 17 pages, 8 figures. Accepted by Ap
High Redshift HCN Emission: Dense Star-Forming Molecular Gas in IRAS F10214+4724
Hydrogen cyanide emission in the J=1-0 transition has been detected at
redshift z=2.2858 in IRAS F10214+4724 using the Green Bank Telescope . This is
the second detection of HCN emission at high redshift. The large HCN line
luminosity in F10214 is similar to that in the Cloverleaf (z=2.6) and the
ultra-luminous infrared galaxies Mrk231 and Arp220. This is also true of the
ratio of HCN to CO luminosities. The ratio of far-infrared luminosity to HCN
luminosity, an indicator of the star formation rate per solar mass of dense
gas, follows the correlation found for normal spirals and infrared luminous
starburst galaxies. F10214 clearly contains a starburst that contributes,
together with its embedded quasar, to its overall infrared luminosity. A new
technique for removing spectral baselines in the search for weak, broad
emission lines is presented.Comment: 9 pages, 2 figures; accepted ApJ(Letters
Kwok-Yung Lo
Radio astronomer and physicist Kwok-Yung âFredâ Lo was born on 19 October 1947 in Nanjing, China. The third of six sons, he grew up in Hong Kong, where his father had moved his antique business in 1949 in search of better opportunities. Fred came to the US in 1965 to attend MIT, where he earned his BS in 1969 and a PhD in 1974, both in physics. His thesis, titled âInterstellar microwave radiation and early stellar evolution,â was supervised by radio astronomer Bernard Burke
Thomas Aquinas and the Generation of the Embryo: Being Human before the Rational Soul
Thesis advisor: Peter KreeftThomas Aquinas is generally viewed as the chief proponent of the theory of delayed animation, the view that the human embryo does not at first have the rational soul proper to human beings. Thomas follows Aristotle's embryology, in which an embryo is animated by a succession of souls. The first is a nutritive soul, having the powers of growth, nutrition, and generation. The second is a sensitive soul, having the additional powers of locomotion and sensing. The third and final soul is the human, or rational soul, which virtually includes the nutritive and sensitive souls. Because Thomas holds that there is only one substantial form of a composite, none of these forms overlap to provide continuity. It is therefore exceedingly difficult to speak of the embryo as one enduring subject through the succession of souls. Moreover, because of the way that the nutritive soul is associated with plants, and the sensitive soul is associated with animals, interpreters generally hold that for Thomas the embryo is first a plant, then an animal, and with the advent of the rational soul, finally a human being. Those who write about the ontological status of the embryo assume that delayed animation necessarily entails delayed hominization, that is, that the embryo only becomes human at a later stage of its development, when it receives the rational soul. Those who hold a delayed animation view of the embryo often invoke Thomas' schedule of successive souls in the embryo as a model for viewing it as not yet human in early stages of development, linking hominization to the ability to perform intellectual operations. That Thomas specifies that a body must be sufficiently organized before the advent of the rational soul seems to them to solidify their view of the embryo as not sufficiently organized to be truly human. Additionally, even outside of an explicitly Thomist framework, Thomist metaphysical principles are often invoked in arguments that center on twinning and totipotency of blastomeres in the early embryo, and whether that early embryo is one individual if it is potentially many. Those who hold immediate animation views (i.e., the embryo receives the rational soul at once, with no mediate states) often adopt the strategy of importing modern data on the internal organization and self-directed development of the embryo, and argue that if only Thomas had known that the zygote was not unformed and undifferentiated, that it has within itself all it needs to become a mature adult human, he would have held that the embryo is immediately suited to receive the rational soul, and thus is human from conception. In this way they attempt to employ a change in scientific data to negate the need for a succession of forms in the embryo. The author identifies the being of the human embryo as a prior metaphysical problem within Thomas' work, and advances a different interpretation of his views: that the embryo, even before the advent of the rational soul, is human. To establish this claim, she traces the problems which emerge in the current debate about when the embryo becomes human, and argues that contrary to expectation, it is not necessary to equate immediate rational animation with immediate hominization, demonstrating that all other approaches yield results entirely untenable for Thomas. A survey of texts reveals that Thomas did in fact view the embryo as human before the rational soul, though he does not methodically work out the implications of that view in a number of areas. Moreover, a distinction based on a passage in Aristotle's Generation of Animals with regard to an additional meaning of generation may resolve the ambivalence in Thomas' account of the embryo as passive under the formative power of the father's semen. Finally, a third meaning of generation is offered to show that Thomas recognized and wished to resolve the difficulty of explaining the continuity and identify of the embryo in the succession of souls. What results is an immediate hominization view of the embryo that, because it accommodates Thomas' succession of souls and does not depend upon importing modern biological data on the embryo, is consistent with Thomas' account, and is thoroughly cognizant of the way Thomas viewed human nature and the final end of human being.Thesis (PhD) â Boston College, 2013.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Philosophy
HCN Observations of Dense Star-Forming Gas in High Redshift Galaxies
We present here the sensitive HCN(1-0) observations made with the VLA of two
submillimeter galaxies and two QSOs at high-redshift. HCN emission is the
signature of dense molecular gas found in GMC cores, the actual sites of
massive star formation. We have made the first detection of HCN in a
submillimeter galaxy, SMM J16359+6612. The HCN emission is seen with a signal
to noise ratio of 4 and appears to be resolved as a double-source of
\approxlt 2'' separation. Our new HCN observations, combined with previous
HCN detections and upper limits, show that the FIR/HCN ratios in these high
redshift sources lie systematically above the FIR/HCN correlation established
for nearby galaxies by about a factor of 2. Even considering the scatter in the
data and the presence of upper limits, this is an indication that the FIR/HCN
ratios for the early Universe molecular emission line galaxies (EMGs) deviate
from the correlation that fits Galactic giant molecular cloud cores, normal
spirals, LIRGs, and ULIRGs. This indicates that the star formation rate per
solar mass of dense molecular gas is higher in the high- objects than in
local galaxies including normal spirals LIRGs and ULIRGs. The limited HCN
detections at high-redshift show that the HCN/CO ratios for the high-
objects are high and are comparable to those of the local ULIRGs rather than
those of normal spirals. This indicates that EMGs have a high fraction of dense
molecular gas compared to total molecular gas traced by CO emission.Comment: 14 pages including 4 figures; ApJL accepte
Kwok-Yung Lo
Radio astronomer and physicist Kwok-Yung âFredâ Lo was born on 19 October 1947 in Nanjing, China. The third of six sons, he grew up in Hong Kong, where his father had moved his antique business in 1949 in search of better opportunities. Fred came to the US in 1965 to attend MIT, where he earned his BS in 1969 and a PhD in 1974, both in physics. His thesis, titled âInterstellar microwave radiation and early stellar evolution,â was supervised by radio astronomer Bernard Burke
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