1202.0278
Dust attenuation and H-alpha SFR of z~0.5 galaxies
Ly, Malkan, Kashikawa, Ota, Shimasaku, Iye, Currie
Identify ~600 Halpha line emitting galaxies in the Subaru Deep Field: lower luminosities, augmented with multi-wavelength coverage, large fraction spectroscopically confirmed compared to other surveys. Measure Balmer decrement for nearly 60 galaxies; they indicate an average extinction of A=0.7 mag (with large error). Decrement systematically increases with higher H-alpha luminosities and with larger stellar masses, in agreement with previous studies with sparser samples. SFR estimated from SED is reliable [?]. The SED-predicted H-alpha luminosity agrees with H-alpha narrow-band measurements over 3 dex. Use the SED SFRs to test different statistically-based dust corrections for H-alpha, find that adopting one magnitude of extinction is inappropriate: galaxies with lower luminosities are less reddened. Find that the luminosity-dependent dust correction of Hopkins+ yields consistent results over 3 dex. Comparisons are only possible by assuming that stellar reddening is roughly half of nebular reddening. The strong correspondence argue that with SED modeling, can derive reliable intrinsic SFRs even in the absence of H-alpha measurements at z~0.5.
* I don't understand what the significance of this paper is... perhaps the prediction of H-alpha (hence SF) based on SED and dust?
1202.0280
Discovery of a compact gas-rich DLA galaxy at z=2.2: evidences for a starburst-driven outflow
Noterdaeme, Laursen, ,Petitjean, Vergani, Maureira, Ledoux, Fynbo, Lopez, Srianand
Ly-a peaks are double, indicating presence of starburst-driven outflows, in agreement with large SFR (25 Msun/yr), together with a small size and low mass of the galaxy (1e10 Msun).
1202.0287
Cosmography from two-image lens systems: overcoming the lens profile slope degeneracy
Suyu
The time-delay distance depends sensitively on the radial profile slope of the lens mass distribution; consequently, the lens slope must be accurately constrained for cosmological studies. Show that the slope cannot be constrained in 2-image systems with single component compact sources, whereas it can be constrained in systems with two-component sources provided the separations between the image components can be measured with milliarcsecond precisions, which is not feasible in most systems. In contrast, demonstrate that spatially extended images of the source galaxy in two-image systems break the radial slope degeneracy and allow time delay to be measured with uncertainties of a few percent. ...
1202.0290
The contribution of starbursts and normal galaxies to IR luminosity functions at z<2
Sargent, Bethermin, Daddi, Elbaz
Present parameter-less approach to predict the shape of the IR LF at z<2. Requires (1) the z evolution of the stellar mass function of SF galaxies, (2) the evolution of the sSFR of main-sequence galaxies, and (3) the double-Gaussian decomposition of the sSFR-distribution at fixed stellar mass into a contribution (assumed z- and mass-invariant) from MS and starburst activity.
1202.0308
An oxygen abundance gradient into the outer disk of M81
Patterson, Walterbos, Kennicutt, Chiappini, Thilker
Present Halpha imaging of outer disk of M81 and luminosities for 40 HII regions out to 3x optical radius. Find overall oxygen abundance gradient of -0.013 dex/kpc over the entire range, significantly flatter than found in previous studies limited to optical disk. Shallow abundance gradient of M81 is likely a result of the interaction history of this galaxy.
1202.0311
All curled up: a numerical investigation of shock-bubble interactions and the role of vortices in heating galaxy clusters
Friedman, Heinz, Churazov
* Richtmyer-Meshkov instability: occurs when an interface between fluids of differing density is impulsively accelerated, e.g., by the passage of a shock wave. 3 stages: (1) deterministic vortex-dominated growth, (2) regime featuring both deterministic and stochastic growth of small-scale features, and ending with turbulent mixing of the layer with surrounding gas. Turbulent mixing in SNe. Can be considered the impulsive-acceleration limit of the RT instability.
* Rayleigh-Taylor instability: instability of an interface between two fluids of different densities, which occurs when the lighter fluid is pushing the heavier fluid. E.g., gravity acting on two fluids of different density, with the dense fluid above a fluid of lesser density.
Jets from AGN inflate cavities of low density relativistic plasma and drive shock and sound waves into the ICM. When these waves overrun previously inflated cavities, they form a differentially rotating vortex through the Richtmyer-Meshkov instability. The dissipation of energy captured in the vortex can contribute to the feedback of energy into the atmospheres of cool core clusters. Using a series of hydrodynamic simulations investigate the efficiency of this process: calculate the kinetic energy of the vortex by decomposing the velocity field into its irrotational and solenoidal parts. Compared to the two-dimensional case, the 3d RM instability is about a factor of 2 more efficient. For strong shocks, the vortex becomes dynamically unstable, quickly dissipating its energy via a turbulent cascade. Derive a number of diagnostics for observations and laboratory experiments of shock-bubble interactions, like the shock-vortex standoff distance, which can be used to derive lower limits on the Mach number. The differential rotation of the vortex fifeld leads to viscous dissipation, which is sufficiently efficient to react to cluster cooling and to dissipate the vortex energy within the cooling radius of the cluster for a reasonable range of vortex parameters. For sufficiently large filling factors, this process could contribute significantly to AGN feedback in galaxy clusters.
* TMI in the abstract.
1202.0354
The local volume HI survey: galaxy kinematics
Kirby, Koribalski, Jerjen, Lopez-Sanchez
Present detailed analysis of the neutral hydrogen kinematics of 12 nearby dwarf irregular galaxies observed as part of the local volume HI survey. Measure HI rotation curve with inclination, position angle. Evidence of tidal interaction, extraplanar HI gas. Discuss under what circumstances the 21cm emission line profile can accurately predict the galaxy's rotation velocity for TF relation studies.
1202.0358
The influences of the Magellanic clouds on the galaxy: pole shift, warp, and SFH
Bekki
LMC influence on the evolution of MW after LMC enters into the virial radius of DM halo of the galaxy for the first time. N-body sims. Influences of the LMC on the precession rate, the outer stellar and gaseous structures, and the SFH of the MW. Results: the dynamical interaction can cause "pole shift" (irregular precession/nutation) of the MW and the typical rate of pole shift corresponding to 7 muas/yr. The LMC-Galaxy interaction induces the formation of the outer warp structures of the galaxy, which confirms the results of previous numerical simulations on the formation of the galactic warp. Interaction also induces formation of R>20kpc spiral arms and increases the vertical velocity dispersion of the outer disk significantly. The mean SFR of the MW for the last several Gyrs can be hardly influenced by the LMC's tidal force. The age and metallicity distribution of stars in the solar neighborhood only slightly changed.
1202.0402
Herschel-ATLAS: towards a sample of ~1000 strongly-lensed galaxies
Gonzalez-Nuevo, ..Cooray, ... et al
HALOS (Hershcel-ATLAS lensed objects selection): a method for efficiently selecting fainter candidate strongly lensed galaxies, reaching a surface density of 1.5~2 deg^-2. Candidate lenses are identified in the VIKING near-IR catalog. Using the available information on candidate sources and candidate lenses, tentatively estimate a ~72% purity. The z distribution of the candidate lensed sources is close to that reported for most previous surveys for lensed galaxies, while that of candidate lenses extends to substantially higher z than found in other surveys.
* Method seems to depend on colors, especially in the IR, to get the high-z objects, plus a foreground galaxy.
1202.0494
Color gradients in galaxies out to z~3: dependence on galaxy properties
Welikala, Kneib
HST observations of GOODS-S out to z~3 and i_AB < 25.5 and characterize their dependence on galaxy properties. Color = v-i color outside and inside of R_50. Gradient shows little evolution with redshift up to z~1 but increases from z~1 to 2 before flattening out. Also increases with apparent magnitude, with a median value of 0.24 mags at i_AB~25.5. Strong color dependence, with the bluest galaxies having cores that are bluer relative to their outskirts. Probe the redshift evolution by stacking galaxies and measuring the radial variation of v-i color within. At z<0.5, the cneers are slightly redder than outskirts. At z~1 and -22<M_I<-21, galaxies are bluer in their cores by 0.1 mag, compared to outskirts. For z>1, galaxies show increasingly bluer cores while the color of the outskirts does not change as rapidly. At z~2.5 and -22<M_i<-21, observe a difference, on average, of 0.4 mags between the centre and outskirts. The observed color gradients may indicate that strong SF in galaxies at z>2 is concentrated in their central regions. These color gradients and their dependence on observable properties could also have a significant impact on shear measurements in upcoming WL cosmological surveys.
1202.0548
A measurement of gravitational lensing of the CMB using SPT data
van Engelen, Keisler, Zahn, ... Carlstrom, ... Holzapfel, et al
Measure power spectrum of the projected gravitational potential from CMB lensing in SPT. Constrain signal to 0.86 pm 0.16 of that expected amplitude from LCDM, with no lensing disfavored at 6.3 sigma. Marginalizing over LCDM cosmological models allowed by the WMAP7 results in a measurement of A_lens=0.9 pm 0.19, indicating that the amplitude of matter fluctations over the redshift range 0.5<z< probed by CMB lensing is in good agreement with predictions. Consistency checks: Clear detection of the lensing signature in CMB maps filtered to have no overlap in Fourier space, as well as a "curl" diagnostic that is consistent with the signal expected from LCDM. Perform a detailed study of bias in the measurement due to noise, foregrounds, and other effects and determine that these contributions are relatively small compared to the statistical uncertainty in the measurement. Combine this lensing measurement with results from WMAP7 to improve constraints on cosmo parameters when compared to those from WMAP7 alone; find a x3.9 improvement in the measurement of the spatial curvature of the Universe, a 10% improvement in sigma_8, and 5% improvement in w. Addition of lensing data improve the measurement of w by 15%.
1202.0547
Can dust emission be used to map the interstellar medium in high-z galaxies? Results from the Herschel reference survey
Eales, ... Cooray, ... et al
Alternative to CO/21cm method for estimating the ISM mass in galaxy: use the continuum dust emission. Calibrate the dust method using the CO and 21-cm observation to provide an independent estimate of the mass of H in each galaxy, solving the problem of the uncertain 'X factor' for the molecular gas by minimizing the dispersion in the ratio of the masses estimated using the two methods. With the calibration for the dust method and the estimate of the X-factor produced in this way, the dispersion in the ratio of the two gas masses is 30%, which gives and upper limit on the fundamental accuracy of the dust method. The calibration we obtain for the dust method is very similar to an independent HErschel measurement for M31 and to the calibration for the MW from Planck measurements.
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