750 research outputs found
A Cultural Comparison of the ''Dark Constellations'' in the Milky Way
Cultures around the world find meaning in the groupings of stars and features in the Milky Way. The striking appearance of our Galaxy in the night sky serves as a reference to traditional knowledge, encoding science and culture to a memory space, becoming part of their overarching cosmologies. This paper examines traditional views of the Milky Way from cultures around the world, primarily in the Southern Hemisphere. These views comprise dark constellations: familiar shapes made up of the dark dust lanes in the Milky Way, rather than the bright stars. Some of the better-known examples include the celestial emu from Aboriginal traditions of Australia, and the llama in Inca traditions of the Andes. We conduct a comparative analysis of cultural perceptions of ‘dark constellations’ in the Milky Way, examining common cultural themes and meanings at the crossroads of Indigenous Knowledge and Western science with applications to topics ranging from Indigenous Studies to psychology.Fil: Gullberg, Steven R.. Oklahoma State University; Estados UnidosFil: Hamacher, Duane. University of Melbourne; AustraliaFil: Lopez, Alejandro Martin. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Ciencias Antropológicas. Sección de Etnología y Etnografía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mejuto, Javier. Universidad Nacional Autónoma de Honduras; HondurasFil: Munro, Andrew M.. University of Oklahoma; Estados UnidosFil: Orchiston, Wayne. University of Southern Queensland; Australia. National Astronomical Research Institute of Thailand; Tailandi
The Role of Repeated Exposure to Multimodal Input in Incidental Acquisition of Foreign Language Vocabulary
Prior research has reported incidental vocabulary acquisition with complete beginners in a foreign language (FL), within 8 exposures to auditory and written FL word forms presented with a picture depicting their meaning. However, important questions remain about whether acquisition occurs with fewer exposures to FL words in a multimodal situation and whether there is a repeated exposure effect. Here we report a study where the number of exposures to FL words in an incidental learning phase varied between 2, 4, 6, and 8 exposures. Following the incidental learning phase, participants completed an explicit learning task where they learned to recognize written translation equivalents of auditory FL word forms, half of which had occurred in the incidental learning phase. The results showed that participants performed better on the words they had previously been exposed to, and that this incidental learning effect occurred from as little as 2 exposures to the multimodal stimuli. In addition, repeated exposure to the stimuli was found to have a larger impact on learning during the first few exposures and decrease thereafter, suggesting that the effects of repeated exposure on vocabulary acquisition are not necessarily constant
The redshift distribution of dusty star forming galaxies from the SPT survey
We use the Atacama Large Millimeter/submillimeter Array (ALMA) in Cycle 1 to
determine spectroscopic redshifts of high-redshift dusty star-forming galaxies
(DSFGs) selected by their 1.4mm continuum emission in the South Pole Telescope
(SPT) survey. We present ALMA 3mm spectral scans between 84-114GHz for 15
galaxies and targeted ALMA 1mm observations for an additional eight sources.
Our observations yield 30 new line detections from CO, [CI] , [NII] , H_2O and
NH_3. We further present APEX [CII] and CO mid-J observations for seven sources
for which only a single line was detected in spectral-scan data from ALMA Cycle
0 or Cycle 1. We combine the new observations with previously published and new
mm/submm line and photometric data of the SPT-selected DSFGs to study their
redshift distribution. The combined data yield 39 spectroscopic redshifts from
molecular lines, a success rate of >85%. Our sample represents the largest data
set of its kind today and has the highest spectroscopic completeness among all
redshift surveys of high-z DSFGs. The median of the redshift distribution is
z=3.9+/-0.4, and the highest-redshift source in our sample is at z=5.8. We
discuss how the selection of our sources affects the redshift distribution,
focusing on source brightness, selection wavelength, and strong gravitational
lensing. We correct for the effect of gravitational lensing and find the
redshift distribution for 1.4mm-selected sources with a median redshift of
z=3.1+/-0.3. Comparing to redshift distributions selected at shorter
wavelengths from the literature, we show that selection wavelength affects the
shape of the redshift distribution
The Rest-Frame Submillimeter Spectrum of High-Redshift, Dusty, Star-Forming Galaxies
We present the average rest-frame spectrum of high-redshift dusty,
star-forming galaxies from 250-770GHz. This spectrum was constructed by
stacking ALMA 3mm spectra of 22 such sources discovered by the South Pole
Telescope and spanning z=2.0-5.7. In addition to multiple bright spectral
features of 12CO, [CI], and H2O, we also detect several faint transitions of
13CO, HCN, HNC, HCO+, and CN, and use the observed line strengths to
characterize the typical properties of the interstellar medium of these
high-redshift starburst galaxies. We find that the 13CO brightness in these
objects is comparable to that of the only other z>2 star-forming galaxy in
which 13CO has been observed. We show that the emission from the high-critical
density molecules HCN, HNC, HCO+, and CN is consistent with a warm, dense
medium with T_kin ~ 55K and n_H2 >~ 10^5.5 cm^-3. High molecular hydrogen
densities are required to reproduce the observed line ratios, and we
demonstrate that alternatives to purely collisional excitation are unlikely to
be significant for the bulk of these systems. We quantify the average emission
from several species with no individually detected transitions, and find
emission from the hydride CH and the linear molecule CCH for the first time at
high redshift, indicating that these molecules may be powerful probes of
interstellar chemistry in high-redshift systems. These observations represent
the first constraints on many molecular species with rest-frame transitions
from 0.4-1.2mm in star-forming systems at high redshift, and will be invaluable
in making effective use of ALMA in full science operations.Comment: 19 pages, 10 figures (2 in appendices); accepted for publication in
Ap
SPT 0538-50: Physical conditions in the ISM of a strongly lensed dusty star-forming galaxy at z=2.8
We present observations of SPT-S J053816-5030.8, a gravitationally-lensed
dusty star forming galaxy (DSFG) at z = 2.7817, first discovered at millimeter
wavelengths by the South Pole Telescope. SPT 0538-50 is typical of the
brightest sources found by wide-field millimeter-wavelength surveys, being
lensed by an intervening galaxy at moderate redshift (in this instance, at z =
0.441). We present a wide array of multi-wavelength spectroscopic and
photometric data on SPT 0538-50, including data from ALMA, Herschel PACS and
SPIRE, Hubble, Spitzer, VLT, ATCA, APEX, and the SMA. We use high resolution
imaging from HST to de-blend SPT 0538-50, separating DSFG emission from that of
the foreground lens. Combined with a source model derived from ALMA imaging
(which suggests a magnification factor of 21 +/- 4), we derive the intrinsic
properties of SPT 0538-50, including the stellar mass, far-IR luminosity, star
formation rate, molecular gas mass, and - using molecular line fluxes - the
excitation conditions within the ISM. The derived physical properties argue
that we are witnessing compact, merger-driven star formation in SPT 0538-50,
similar to local starburst galaxies, and unlike that seen in some other DSFGs
at this epoch.Comment: 16 pages, 11 figures. Accepted for publication in Ap
The Dragonfly Galaxy: II. ALMA unveils a triple merger and gas exchange in a hyper-luminous radio galaxy at z = 2
The Dragonfly Galaxy (MRC 0152-209), at redshift z ~ 2, is one of the most vigorously star-forming radio galaxies in the Universe. What triggered its activity? We present ALMA Cycle 2 observations of cold molecular CO(6−5) gas and dust, which reveal that this is likely a gas-rich triple merger. It consists of a close double nucleus (separation ~4 kpc) and a weak CO-emitter at ~10 kpc distance, all of which have counterparts in HST/NICMOS imagery. The hyper-luminous starburst and powerful radio-AGN were triggered at this precoalescent stage of the merger. The CO(6−5) traces dense molecular gas in the central region, and complements existing CO(1−0) data, which reveal more widespread tidal debris of cold gas. We also find ~1010 M☉ of molecular gas with enhanced excitation at the highest velocities. At least 20−50% of this high-excitation, high-velocity gas shows kinematics that suggests it is being displaced and redistributed within the merger, although with line-of-sight velocities of |v| < 500 km s-1, this gas will probably not escape the system. The processes that drive the redistribution of cold gas are likely related to either the gravitational interaction between two kpc-scale discs, or starburst/AGN-driven outflows. We estimate that the rate at which the molecular gas is redistributed is at least [Ṁentity!#x2009!]~ 1200 ± 500 M☉ yr-1, and could perhaps even approach the star formation rate of ~3000 ± 800 M☉ yr-1. The fact that the gas depletion and gas redistribution timescales are similar implies that dynamical processes can be important in the evolution of massive high-z galaxies
Attention to Speech-Accompanying Gestures: Eye Movements and Information Uptake
There is growing evidence that addressees in interaction integrate the semantic information conveyed by speakers’ gestures. Little is known, however, about whether and how addressees’ attention to gestures and the integration of gestural information can be modulated. This study examines the influence of a social factor (speakers’ gaze to their own gestures), and two physical factors (the gesture’s location in gesture space and gestural holds) on addressees’ overt visual attention to gestures (direct fixations of gestures) and their uptake of gestural information. It also examines the relationship between gaze and uptake. The results indicate that addressees’ overt visual attention to gestures is affected both by speakers’ gaze and holds but for different reasons, whereas location in space plays no role. Addressees’ uptake of gesture information is only influenced by speakers’ gaze. There is little evidence of a direct relationship between addressees’ direct fixations of gestures and their uptake
An ALMA view of the interstellar medium of the z = 4.77 lensed starburst SPT-S J213242-5802.9
We present ALMA detections of the [NII] 205 μm and CO(12−11) emission lines, and the tentative detection of [CI] ^3P_1–^3P_0 for the strongly lensed (μ = 5.7 ± 0.5) dusty, star-forming galaxy SPT-S J213242-5802.9 (hereafter SPT2132-58) at z = 4.77. The [NII] and CO(12−11) lines are detected at 11.5 and 8.5σ levels, respectively, by our band 6 observations. The [CI] line is detected at 3.2σ after a reanalysis of existing band 3 data. The [CI] luminosity implies a gas mass of (3.8 ± 1.2) × 10^(10)M_⊙, and, consequently, a very short depletion timescale of 34 ± 13 Myr and a CO luminosity to gas mass conversion factor α_(CO) of 1.0 ± 0.3 M_⊙ (K km s^(-1) pc^2)^(-1). SPT2132-58 is an extreme starburst with an intrinsic star formation rate of 1100 ± 200 M_⊙/yr. We find a [CII]/[NII] ratio of 26 ± 6, which is the highest ratio reported at z > 4. This suggests that SPT2132-58 hosts an evolved interstellar medium (0.5 Z_⊙< Z < 1.5 Z_⊙), which may be dominated by photodissociation regions. The CO(2−1) and CO(5−4) transitions have lower CO to far-infrared ratios than local and high-redshift samples, while CO(12−11) is similar to these samples, suggesting the presence of an additional very excited component or an active galactic nucleus
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