44 research outputs found
Archival of Seasat-A satellite scatterometer data merged with in situ data at selected, illuminated sites over the ocean
A large data base of Seasat-A Satellite Scatterometer (SASS) measurements merged with high-quality surface-truth wind, wave, and temperature data has been documented. The data base was developed for all times when selected in situ measurement sites were within the SASS footprint. Data were obtained from 42 sites located in the coastal waters of North America, Australia, Western Europe, and Japan and were assembled by correlating the SASS and surface-truth measurements in both time and distance. These data have been archived on a set of nine-track 6250 bpi ASCII coded magnetic tapes, which are available from the National Technical Information Service
Treading Water: Tools to Help US Coastal Communities Plan for Sea Level Rise Impacts
As communities grapple with rising seas and more frequent flooding events, they need improved projections of future rising and flooding over multiple time horizons, to assist in a multitude of planning efforts. There are currently a few different tools available that communities can use to plan, including the Sea Level Report Card and products generated by a United States. Federal interagency task force on sea level rise. These tools are a start, but it is recognized that they are not necessarily enough at present to provide communities with the type of information needed to support decisions that range from seasonal to decadal in nature, generally over relatively small geographic regions. The largest need seems to come from integrated models and tools. Agencies need to work with communities to develop tools that integrate several aspects (rainfall, tides, etc.) that affect their coastal flooding problems. They also need a formalized relationship with end users that allows agency products to be responsive to the various needs of managers and decision makers. Existing boundary organizations can be leveraged to meet this need. Focusing on addressing these needs will allow agencies to create robust solutions to flood risks, leading to truly resilient communities
The SAMI Galaxy Survey: a new method to estimate molecular gas surface densities from star formation rates
Stars form in cold molecular clouds. However, molecular gas is difficult to observe because the most abundant molecule (H_2) lacks a permanent dipole moment. Rotational transitions of CO are often used as a tracer of H_2, but CO is much less abundant and the conversion from CO intensity to H2 mass is often highly uncertain. Here we present a new method for estimating the column density of cold molecular gas (ÎŁ_(gas)) using optical spectroscopy. We utilize the spatially resolved Hα maps of flux and velocity dispersion from the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. We derive maps of ÎŁ_(gas) by inverting the multi-freefall star formation relation, which connects the star formation rate surface density (ÎŁ_(SFR)) with ÎŁ_(gas) and the turbulent Mach number (M). Based on the measured range of ÎŁ_(SFR) = 0.005-1.5Mâ yr^(â1) kpc^(â2) and M=18â130, we predict ÎŁ_(gas) = 7â200 Mâ pc^(â2)
in the star-forming regions of our sample of 260 SAMI galaxies. These values are close to previously measured ÎŁ_(gas) obtained directly with unresolved CO observations of similar galaxies at low redshift. We classify each galaxy in our sample as âstar-formingâ (219) or âcomposite/AGN/shockâ (41), and find that in âcomposite/AGN/shockâ galaxies the average ÎŁ_(SFR),
M and ÎŁ_(gas) are enhanced by factors of 2.0, 1.6 and 1.3, respectively, compared to star-forming galaxies. We compare our predictions of ÎŁ_(gas) with those obtained by inverting the KennicuttâSchmidt relation and find that our new method is a factor of 2 more accurate in predicting ÎŁ_(gas), with an average deviation of 32 per cent from the actual ÎŁ_(gas)
The SAMI Galaxy Survey: : extraplanar gas, galactic winds, and their association with star formation history
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society, the version of record is available on line at doi: 10.1093/mnras/stw017We investigate a sample of 40 local, main-sequence, edge-on disc galaxies using integral field spectroscopy with the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey to understand the link between properties of the extraplanar gas and their host galaxies. The kinematics properties of the extraplanar gas, including velocity asymmetries and increased dispersion, are used to differentiate galaxies hosting large-scale galactic winds from those dominated by the extended diffuse ionized gas. We find rather that a spectrum of diffuse gas-dominated to wind dominated galaxies exist. The wind-dominated galaxies span a wide range of star formation rates () across the whole stellar mass range of the sample (). The wind galaxies also span a wide range in SFR surface densities () that is much lower than the canonical threshold of . The wind galaxies on average have higher SFR surface densities and higher values than those without strong wind signatures. The enhanced indicates that bursts of star formation in the recent past are necessary for driving large-scale galactic winds. We demonstrate with Sloan Digital Sky Survey data that galaxies with high SFR surface density have experienced bursts of star formation in the recent past. Our results imply that the galactic winds revealed in our study are indeed driven by bursts of star formation, and thus probing star formation in the time domain is crucial for finding and understanding galactic winds.Peer reviewe
The SAMI Galaxy Survey: mass-kinematics scaling relations
We use data from the Sydney-AAO Multi-object Integral-field spectroscopy (SAMI) Galaxy Survey to study the dynamical scaling relation between galaxy stellar mass Mâ and the general kinematic parameter S_K = \sqrt{K V_rot^2 + Ï ^2} that combines rotation velocity Vrot and velocity dispersion Ï. We show that the log Mâ - log SK relation: (1) is linear above limits set by properties of the samples and observations; (2) has slightly different slope when derived from stellar or gas kinematic measurements; (3) applies to both early-type and late-type galaxies and has smaller scatter than either the Tully-Fisher relation (log Mâ - log Vrot) for late types or the Faber-Jackson relation (log Mâ - log Ï) for early types; and (4) has scatter that is only weakly sensitive to the value of K, with minimum scatter for K in the range 0.4 and 0.7. We compare SK to the aperture second moment (the `aperture velocity dispersion') measured from the integrated spectrum within a 3-arcsecond radius aperture (Ï _{3^' ' }}). We find that while SK and Ï _{3^' ' }} are in general tightly correlated, the log Mâ - log SK relation has less scatter than the \log M_* - \log Ï _{3^' ' }} relation.The SAMI Galaxy
Survey is supported by the Australian Research Council Centre
of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013, the Australian
Research Council Centre of Excellence for All-sky Astrophysics
(CAASTRO), through project number CE110001020, and other
participating institutions. The SAMI Galaxy Survey website is samisurvey.org.
DB is supported by an Australia Government Research Training Program Scholarship and ASTRO 3D. FDE acknowledges
funding through the H2020 ERC Consolidator Grant 683184.
JBH is supported by an ARC Laureate Fellowship that funds
JvdS and an ARC Federation Fellowship that funded the SAMI
prototype. JJB acknowledges support of an Australian Research
Council Future Fellowship (FT180100231). JvdS is funded under
Bland-Hawthornâs ARC Laureate Fellowship (FL140100278). NS
acknowledges support of a University of Sydney Postdoctoral Research Fellowship. Parts of this research were conducted by ASTRO
3D, through project number CE170100013. LC is the recipient of
an Australian Research Council Future Fellowship (FT180100066)
funded by the Australian Government. SB acknowledges the funding support from the Australian Research Council through a Future
Fellowship (FT140101166). SMC acknowledges the support of an
Australian Research Council Future Fellowship (FT100100457).
BG is the recipient of an Australian Research Council Future Fellowship (FT140101202). MSO acknowledges the funding support
from the Australian Research Council through a Future Fellowship
(FT140100255). Support for AMM is provided by NASA through
Hubble Fellowship grant #HST-HF2-51377 awarded by the Space
Telescope Science Institute, which is operated by the Association
of Universities for Research in Astronomy, Inc., for NASA, under
contract NAS5-26555. SKY acknowledges support from the Korean
National Research Foundation (2017R1A2A1A05001116) and by the Yonsei University Future Leading Research Initiative (2015-
22-0064)
Sensitization in Transplantation: Assessment of Risk (STAR) 2017 Working Group Meeting Report
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144684/1/ajt14752_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144684/2/ajt14752.pd
The SAMI Galaxy Survey: revisiting galaxy classification through high-order stellar kinematics
Recent cosmological hydrodynamical simulations suggest that integral field spectroscopy can connect the high-order stellar kinematic moments h3 (~skewness) and h4 (~kurtosis) in galaxies to their cosmological assembly history. Here, we assess these results by measuring the stellar kinematics on a sample of 315 galaxies, without a morphological selection, using two-dimensional integral field data from the SAMI Galaxy Survey. Proxies for the spin parameter () and ellipticity () are used to separate fast and slow rotators; there exists a good correspondence to regular and non-regular rotators, respectively, as also seen in earlier studies. We confirm that regular rotators show a strong h3 versus anti-correlation, whereas quasi-regular and non-regular rotators show a more vertical relation in h3 and . Motivated by recent cosmological simulations, we develop an alternative approach to kinematically classify galaxies from their individual h3 versus signatures. Within the SAMI Galaxy Survey, we identify five classes of high-order stellar kinematic signatures using Gaussian mixture models. Class 1 corresponds to slow rotators, whereas Classes 2â5 correspond to fast rotators. We find that galaxies with similar {\lambda }_{{R}_{{\rm{e}}}}\mbox{--}{\epsilon }_{{\rm{e}}} values can show distinctly different {h}_{3}\mbox{--}V/\sigma signatures. Class 5 objects are previously unidentified fast rotators that show a weak h3 versus anti-correlation. From simulations, these objects are predicted to be disk-less galaxies formed by gas-poor mergers. From morphological examination, however, there is evidence for large stellar disks. Instead, Class 5 objects are more likely disturbed galaxies, have counter-rotating bulges, or bars in edge-on galaxies. Finally, we interpret the strong anti-correlation in h3 versus as evidence for disks in most fast rotators, suggesting a dearth of gas-poor mergers among fast rotators
The SAMI Galaxy Survey: Cubism and covariance, putting round pegs into square holes
We present a methodology for the regularization and combination of sparse sampled and irregularly gridded observations from fibre-optic multiobject integral field spectroscopy. The approach minimizes interpolation and retains image resolution on combining subpixel dithered data. We discuss the methodology in the context of the Sydney-AAO multiobject integral field spectrograph (SAMI) Galaxy Survey underway at the Anglo-Australian Telescope. The SAMI instrument uses 13 fibre bundles to perform high-multiplex integral field spectroscopy across a 1° diameter field of view. The SAMI Galaxy Survey is targeting ~3000 galaxies drawn from the full range of galaxy environments. We demonstrate the subcritical sampling of the seeing and incomplete fill factor for the integral field bundles results in only a 10 per cent degradation in the final image resolution recovered. We also implement a new methodology for tracking covariance between elements of the resulting data cubes which retains 90 per cent of the covariance information while incurring only a modest increase in the survey data volume
THE SAMI GALAXY SURVEY: REVISITING GALAXY CLASSIFICATION THROUGH HIGH-ORDER STELLAR KINEMATICS
Recent cosmological hydrodynamical simulations suggest that integral field
spectroscopy can connect the high-order stellar kinematic moments h3
(~skewness) and h4 (~kurtosis) in galaxies to their cosmological assembly
history. Here, we assess these results by measuring the stellar kinematics on a
sample of 315 galaxies, without a morphological selection, using 2D integral
field data from the SAMI Galaxy Survey. A proxy for the spin parameter
() and ellipticity () are used to separate fast and
slow rotators; there exists a good correspondence to regular and non-regular
rotators, respectively, as also seen in earlier studies. We confirm that
regular rotators show a strong h3 versus anti-correlation, whereas
quasi-regular and non-regular rotators show a more vertical relation in h3 and
. Motivated by recent cosmological simulations, we develop an
alternative approach to kinematically classify galaxies from their individual
h3 versus signatures. We identify five classes of high-order stellar
kinematic signatures using Gaussian mixture models. Class 1 corresponds to slow
rotators, whereas Classes 2-5 correspond to fast rotators. We find that
galaxies with similar values can show distinctly
different h3- signatures. Class 5 objects are previously unidentified
fast rotators that show a weak h3 versus anti-correlation. These
objects are predicted to be disk-less galaxies formed by gas-poor mergers. From
morphological examination, however, there is evidence for large stellar disks.
Instead, Class 5 objects are more likely disturbed galaxies, have
counter-rotating bulges, or bars in edge-on galaxies. Finally, we interpret the
strong anti-correlation in h3 versus as evidence for disks in most
fast rotators, suggesting a dearth of gas-poor mergers among fast rotators.Comment: Accepted for Publication in The Astrophysical Journal. 35 pages and
30 figures, abstract abridged for arXiv submission. The key figures of the
paper are: 7, 11, 12 , and 1
AVONET: morphological, ecological and geographical data for all birds
Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when speciesâlevel information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity