4,444 research outputs found
SINFONI Observations of Starclusters in Starburst Galaxies
We have used ESO's new NIR IFS SINFONI during its Science Verification period
to observe the central regions of local starburst galaxies. Being Science
Verification observations, the aim was two-fold: to demonstrate SINFONI's
capabilities while obtaining information on the nature of starclusters in
starburst galaxies. The targets chosen include a number of the brighter
clusters in NGC1808 and NGC253. Here we present first results.Comment: Submitted to "Adaptive Optics-Assisted Integral-Field Spectroscopy",
Rutten R.G.M., Benn C.R., Mendez J., eds., May 2005, La Palma (Spain), New
Astr. Re
By-Law 6 Concerning Registration Fees, Educational Support Fee, Student Services Fee and User Fees
En esta tesis se estudian los mecanismos de formación del léxico en la lengua maká (familia lingüística mataguaya) hablada actualmente en diversos distritos en las afueras de Asunción, Paraguay, con el objeto de contribuir al estudio y la documentación de la lengua, así como a los estudios tipológicos y areales. Dado que algunos mecanismos como la derivación, la composición, el simbolismo sonoro y la transferencia semántica han sido escasamente explorados en maká, los capítulos siguientes están dedicados a describir y analizar los procesos morfosintácticos y los aspectos semánticos que intervienen en la formación del léxico general. El estudio contempla también un análisis de la creación de neologismos, en tanto reflejos de la vitalidad de la lengua y de la resistencia del pueblo maká frente a la presión del español. En la medida de lo posible, en cada capítulo se analizan también los fenómenos de lexicalización y gramaticalización que afectan a algunos de los recursos estudiados.Fil. Tacconi, Temis Lucía. Universidad de Buenos Aires. Facultas de Filosofía y Letra
CO distribution in southern S0 galaxies
With the Swedish ESO Submillimeter Telescope (SEST), researchers observed 7 S0 galaxies at 2.6 mm, and detected CO emission in five. Observing four offset positions per galaxy at greater than or equal to 40 seconds from the center, they find significantly extended CO emission in almost all cases. The (lower limits to) H2 masses of several times 10(exp 8) solar magnitude amount to 0.2-0.3 times the HI mass in 4 or 5 galaxies
Imaging the Molecular Gas Properties of a Major Merger Driving the Evolution of a z=2.5 Submillimeter Galaxy
We report the detection of spatially extended CO 1-0 and 5-4 emission in the
z=2.49 submillimeter galaxy (SMG) J123707+6214, using the Expanded Very Large
Array and the Plateau de Bure Interferometer. The large molecular gas reservoir
is spatially resolved into two CO(1-0) components (north-east and south-west;
previously identified in CO 3-2 emission) with gas masses of 4.3 and 3.5 x
10^10 (alpha_CO/0.8) Msun. We thus find that the optically invisible north-east
component slightly dominates the gas mass in this system. The total molecular
gas mass derived from the CO(1-0) observations is ~2.5 times larger than
estimated from CO(3-2). The two components are at approximately the same
redshift, but separated by ~20 kpc in projection. The morphology is consistent
with that of an early-stage merger. The total amount of molecular gas is
sufficient to maintain the intense 500 Msun/yr starburst in this system for at
least ~160 Myr. We derive line brightness temperature ratios of
r_31=0.39+/-0.09 and 0.37+/-0.10, and r_51=0.26+/-0.07 and 0.25+/-0.08 in the
two components, respectively, suggesting that the J>=3 lines are substantially
subthermally excited. This also suggests comparable conditions for star
formation in both components. Given the similar gas masses of both components,
this is consistent with the comparable starburst strengths observed in the
radio continuum emission. Our findings are consistent with other recent studies
that find evidence for lower CO excitation in SMGs than in high-z quasar host
galaxies with comparable gas masses. This may provide supporting evidence that
both populations correspond to different evolutionary stages in the formation
of massive galaxies.Comment: 6 pages, 4 figures, to appear in ApJL (accepted April 12, 2011
The molecular spiral arms of NGC 6946
From CO-12(J=1 to 0) observations at 45 seconds resolution Tacconi and Young (1989) have found evidence for enhancements in both the CO emissivity and the massive star formation efficiency (MSFE) on optical spiral arms of the bright spiral galaxy NGC 6946. In the optically luminous and well-defined spiral arm in the NE quadrant, there are enhancements in both the H2 surface density and MSFE relative to the interarm regions. In contrast, a poorly defined arm in the SW shows no arm-interarm contrast in the MSFE. To further investigate the molecular gas content of these two spiral arms, researchers have made CO-12 J=2 to 1 and 3 to 2 observations with the James Clerk Maxwell Telescope. In the J=2 to 1 line, they made observations of the NE and SW spiral arm and interarm regions in 4 x 9 10 seconds spaced grids (36 points per grid). Because of decreased sensitivity in the J=3 to 2 line, they were limited to mapping the two arm regions in 2 x 3 10 seconds spaced grids (6 points per grid). The centers of each of the grids lie 2.4 minutes to the NE and 2.3 minutes to the SW of the nucleus of NGC 6946. With the CO J=2 to 1 data researchers are able to fully resolve the two observed spiral arms in NGC 6946. In both cases the CO emission is largely confined to the optical spiral arm regions with the peak observed T asterisk sub A being up to 4 times higher on the spiral arms than in the interarm regions. Researchers are currently estimating massive star formation efficiencies on and off the spiral arms through direct comparison of the CO maps with an H alpha image. They are also comparing the CO J=2 to 1 data with an HI map made at similar resolution. Thus, they will be able to determine structure in all components of the IS on scales of less than 20 inches
NIR spectroscopy of the most massive open cluster in the Galaxy: Westerlund 1
Using ISAAC/VLT, we have obtained individual spectra of all NIR-bright stars
in the central 2'x2' of the cluster Westerlund 1 (Wd 1) with a resolution of
R~9000 at a central wavelength of 2.30 micron. This allowed us to determine
radial velocities of ten post-main-sequence stars, and from these values a
velocity dispersion. Assuming virial equilibrium, the dispersion of sigma=8.4
km/s leads to a total dynamical cluster mass of 1.25x10^5 solar masses,
comparable to the photometric mass of the cluster. There is no extra-virial
motion which would have to be interpreted as a signature of cluster expansion
or dissolution.Comment: To appear in the proceedings of IAU 246: "Dynamical Evolution of
Dense Stellar Systems" (E. Vesperini, M. Giersz, A. Sills, eds.
Protected Area Assessment and Establishment in Vanuatu
Resource /Energy Economics and Policy,
Star Formation and Dynamics in the nuclei of AGN
Using adaptive optics on Keck and the VLT in the H- and K-bands, we have
begun a project to probe the dynamics and star formation around AGN on scales
of 0.1arcsec. The stellar content of the nucleus is traced through the
2.29micron CO2-0 and 1.62micron CO6-3 absorption bandheads. These features are
directly spatially resolved, allowing us to measure the extent and distribution
of the nuclear star forming region. The dynamics are traced through the
2.12micron H_2 1-0S(1) and 1.64micron [FeII] emission lines, as well as stellar
absorption features. Matching disk models to the rotation curves at various
position angles allows us to determine the mass of the stellar and gas
components, and constrain the mass of the central black hole. In this
contribution we summarise results for the two type~1 AGN Mkn231 and NGC7469.Comment: contribution to "The interplay among Black Holes, Stars and ISM in
Galactic Nuclei", March 200
EVLA observations of a proto-cluster of molecular gas rich galaxies at z = 4.05
We present observations of the molecular gas in the GN20 proto-cluster of
galaxies at using the Expanded Very Large Array (EVLA). This group of
galaxies is the ideal laboratory for studying the formation of massive galaxies
via luminous, gas-rich starbursts within 1.6 Gyr of the Big Bang. We detect
three galaxies in the proto-cluster in CO 2-1 emission, with gas masses (H)
between and M. The emission
from the brightest source, GN20, is resolved with a size , and has a
clear north-south velocity gradient, possibly indicating ordered rotation. The
gas mass in GN20 is comparable to the stellar mass ( M and M, respectively), and
the sum of gas plus stellar mass is comparable to the dynamical mass of the
system ( M), within a
5kpc radius. There is also evidence for a tidal tail extending another
north of the galaxy with a narrow velocity dispersion. GN20 may be a massive,
gas rich disk that is gravitationally disturbed, but not completely disrupted.
There is one Lyman-break galaxy (BD29079) in the GN20 proto-cluster with an
optical spectroscopic redshift within our search volume, and we set a 3
limit to the molecular gas mass of this galaxy of M.Comment: AAStex format, 4 figures; prepared for the ApJ Letters EVLA special
issu
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