1204.1555
Properties of bulgeless disk galaxies II. star formation as a function of circular velocity
Watson, Martini, Lisenfeld, Wong, Boeker, Schinnerer
Relation between surface density of gas and SFR in 20 inclined, bulge less disk galaxies (Sd-Sdm) using CO(1-0) data from IRAM, HI emission from VLA/EVLA, H-alpha data from MDM, and PAH emission data from Spitzer IRAC. Investigate the efficiency of SF as a function of circular velocity. Edge-on studies show v_circ<120 km/s has large scale heights with diffuse dust lanes and gravitationally stable disk; v_circ > 120 km/s have narrow dust later with small scale heights, gravitationally unstable disk. No transition in SFR within 46 km/s < v_circ < 190 km/s; no transition in disk stability found either. If studied sample here is the same as the edge-on sample, results demonstrate that scale height differences in the cold ISM of bulgeless disk galaxies do not significantly affect the molecular fraction or SF efficiency. Indicates SF happens on scales smaller than the dust scale height.
1204.1562
The observed properties of dwarf galaxies in and around the local group
McConnachie
Study positional, structural and dynamical parameters for all dwarf galaxies 3Mpc from the Sun. Environments: satellite systems of MW and M31; dwarfs in the outer regions of LG; numerous isolated galaxies. Extends to (but not include) galaxies associated with the nearest groups. Made a great table out of all of this.
1204.1577
Disentangling correlated scatter in cluster mass measurements
Noh, Cohn
Galaxy cluster mass estimates in multiwavelength measurements. Scatters in measured cluster masses often sourced by properties of or around the clusters themselves, correlations between mass scatters are frequent and can be significant, with consequences for errors on mass estimates both directly and those obtained via stacking. Use high-res 250 Mpc/h size N-body sim. Obtain mass scatter correlations and covariances for 243 individual clusters along 96 LoS each. Use PCA to characterize scatter trends and variations between clusters. The dominant mass scatter combination is common to many clusters, and tends to dominate the mass scatters when viewing the cluster along its long axis. Also correlate cluster mass scatter, environmental and intrinsic properties, and use PCA to find shared trends between these. Analysis based upon estimated mass distributions for fixed true mass. Extensions to observational data would require further calibration from numerical simulations. Requires more calibration to numerical simulations.
1204.1719
Transfer of life-bearing meteorites from earth to other planets
Hara, Takagi, Kajiura
Take Chicxulub crater event, assume 1cm meteorites--then number of meteorites to reach the exoplanet system (>20 ly) would be >>1. If micro-organisms can survive in interstellar space, then organisms can disperse within the Galaxy over 1e10 years.
1204.1762
Calibration of non thermal pressure in global dark matter simulations of cluster of galaxies
Bode, Ostriker, Cen, Trac
New method for incorporating non thermal pressure from bulk motions of gas into an analytic model of the intracluster medium in clusters of galaxies; based on polytropic equation of state and hydrostatic equilibrium inside gravitational potential wells from DM sims. Gas can have both thermal and non-thermal component with different radial distributions; the overall level of non-thermal support is based on the dynamical state of the halo, such that it is lower in more relaxed clusters. Normalized to X-ray observations and high-res hydrosims. The non-thermal pressure fraction nat r_500 is typically 10-20%, increasing with cluster mass and with redshift. The resulting model cluster properties are in accord wit SZ effect observations of clusters. Inclusion of non thermal pressure reduces the expected angular power spectrum of SZ fluctuations in the microwave by 24%.
1204.1812
Measuring baryon acoustic oscillations on 21 cm intensity fluctuations at moderate redshifts
Mao
Need 300 dishes (instantaneous FoV of ~100 deg sq) can detect BAO over a period of few years.
1204.1842
Multicolor photometry of the nearby galaxy cluster A119
Tian et al
From photometry of ~1 deg sq with 368 galaxies of known spectro-z (238 are cluster members), with photo-z identify 117 additional faint members. Merging along the LoS going on. No significant evidences for morphology and luminosity segregations are found. Environment effect on the star formation properties confirmed. Faint galaxies in low-density regio tend to have longer time scales of SF, smaller mean stellar ages, and lower metallicities of ISM.
1204.1891
"WISEASS" -- a state-of-the-art interactive supernova spectroscopy database
Yaron, Gal-Yam
CCCP--Caltech-Core-Collpase Program, SUSPECT (SUpernova SPECTrum). As the title says.
1204.1917
Spatially resolved kinematics of the central regions of M83: hidden mass signatures and the role of supernovae
Lopez, Davies, Colina, Orban de Xivry
Central 235x140 pc (0.2", or 4pc, resolution) -- gas and stellar kinematics totally unrelated. SNe shape the gas kinematics, dominated by shocks and inflows at scales of 10s of pc, unsuitable to derive general dynamical properties. Nucleus of M83 unlikely to be related to the off-center 'optical nucleus'. ...
1204.1944
Optimized multi-frequency spectra for applications in radiative feedback and cosmological reionization
Mirocha, Skory, Burns, Wise
Radiative transfer algorithms in hydrosim == dramatic improvement in studies of feedback in various astrophysical environments. Methodological limitations and computational expense: spectra of radiation sources generally sampled at a few evenly-spaced discrete emission frequencies. Use 1d transfer calculations to investigate the discrepancies in gas properties surrounding model stars and accreting BHs that arise solely due to spectral discretization. Find: discretization schemes induce errors in the neutral fraction and temperature by factors of 2-3 on average, and by >10x in certain column density regimes. Consequences are most severe for radiative feedback operating on large scales, dense clumps of gas, and media consisting of multiple chemical species. Method for optimally constructing discrete spectra developed, show that in 2 test cases, carefully chosen 4-bin spectra can eliminate errors associated with frequency resolution to high precision. Apply to fully 3d radiation-hydrodynamic simulation of the early universe, find HII region around a primordial stars is substantial altered in both size and morphology, corroborating the 1d prediction that previous methods can be pretty wrong [so which way does the discrepancy go?].
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