Day 314

Tuesday.  71 abstracts.  Twice as many as yesterday.

1210.1849
Conserved actions, maximum entropy and dark matter haloes
Pontzen, Governato

Use maximum entropy arguments to derive the phase space distribution of a virialized DM halo, giving an improved representation of the end product of violent relaxation.  Incorporate physically motivated dynamical constraints which prevent arbitrary redistribution of energy.  Compare predictions with 3 high-res DM sims of varying mass; accurately predicts numerical distribution function, producing an excellent match for the vast majority of particles.  Remaining particles constitute the central cusp of the halo (<4% of the dark matter), which can be accounted for within the presented framework once the short dynamical timescales of the centre are taken into account.

1210.1850
TA-DA: a tool for astrophysical data analysis
Da Rio, Robberto

A new software aimed at greatly simplifying and improving the analysis of stellar photometric data in comparison with theoretical models, and allow the derivation of stellar parameters from multi-band photometry.  An IDL widget-based application.

1210.1851
General formula for the running of fNL
Byrnes, Gong

Compute scale dependence of fNL for multi-field inflation model, allowing for an arbitrary field space metric.  Find: curved field space metric provides another source of scale dependence, which arises from the field-space Riemann curvature tensor and its derivatives.  May be observable in the future if the amplitude of fNL is not too far from the current observational bounds.

1210.1868
Gravitational lenses in the dark Universe
Freitas, Goncalves, Oliveira

How different cosmological models of the Universe affect the probability that a BG source has multiple images related by an angular distance theta_E of the line of sight---the optical depth of gravitational lensing.  examine cosmological models for different values of the density parameter Omega_i (i) CDM, (ii) LCDM, (iii) BE condensate DM model, (iv) Chaplygin gas model, (v) the viscous fluid cosmological model and (vi) holographic DE model.  The dependence of the energy-matter content of the universe profoundly alters the frequency of multiple quasar image.

1210.1886
A survey for the missing hydrogen in high redshift radio sources
Currean, Whiting, Sadler, Bignell

At low z, 40% detection rate of 21cm absorption; but for hosts of z>1 radio galaxies and quasars, remarkably unsuccessful.  High-z selection bias suggested, where the optically brightest objects (UV-luminous in rest frame) are seen, where the gas is ionized by AGN; infer that there must be a population of fainter objects in which H is not ionized, and which exhibit a similar detection rate at lower z.  Take a survey of z>2 radio sources selected by optical faintness.  No detection in any of the 8 sources for which usable data were obtained!  Analysis of SED show ionizing photon rates can be determined for 3 of these, all of which suggest that the objects are above the highest luminosity of a current 21-cm detection.  Possibly: selection biases the sample towards sources which are very steep in the radio band [?]--then the sources may have very extended emission, which would have the effect of reducing the coverage by putative absorbing gas.

1210.2058
Neutrino Astronomy - A review of future experiments
Karle

Current experiments: 10 GeV to 1e9 GeV, but the sensitivity for future IceCube experiments will increase in both directions: down to few/few tens of GeV to measure neutrino mass hierarchy; in the central range of classical optical neutrino telescopes, next generation detectors in Mediterranean and Lake Baikal; radio detectors in ice is among the most promising technologies to increase exposure at 1e9 GeV by more than an order of mag compared to IceCube.

1210.2127
Stellar populations
Peletier

Lectures from a 2011 winter school ("secular evolution of galaxies").  Stellar populations intimately connected to understanding the formation and evolution of galaxies.  Information of stellar populations come from integrated light.  Stellar evolution theory + local observations are used as building blocks to analyze these integrated stellar populations.

1210.2130
The WiggleZ dark energy survey: final data release and cosmological results
Parkinson, .. Blake, .. et al

Cosmological results from WiggleZ Dark Energy Survey.  Use power spectra at z=0.22, 0.41, 0.60, and 0.78, combined with other cosmological datasets.  Limiting factor: theoretical modeling of the power spectrum, including non-inearities, galaxy bias, and z-space distortions.  Assess several different methods for modeling the theoretical PS, testing against simulations (GiggleZ); 6 cosmological parameters and 5 supplementary.  Combine with CMB, results consistent with LCDM concordance cosmology, with measurement of the matter density of Omega_m=0.29pm0.016 and sigma8=0.81-0.84.  Find no evidence for any of the extension parameters being inconsistent with their LCDM model values.  Used CosmoMC.  Released data and random catalogues used to construct the BAO correlation function.

1210.2131
Simultaneous constraints on the number and mass of relativistic species
Riemer-Sorensen, Parkinson, Davis, Blake

Evidence for >3 neutrino species from particle physics and cosmology.  Effects of neutrino mass and number of species can in principle be disentangled for fixed cosmological parameters, but correlation must be included in the analysis.  

1210.2136
Observational constraints on cosmic neutrinos and dark energy revisited
Wang, ... et al

Combine WMAP (CMB), CFHTLS (WL), SDSS+WiggleZ (BAO), H0 observations, Union2.1 (SNIa), and the HST prior, impose constraints on the sum of neutrino masses, the effective number of neutrino species, and w, individually and collectively.  Find: tight upper limit on mnu can be extracted from the full data combination if n_eff and w are fixed, but severly weakened if allowed to vary.  Previous reports on m_nu upper bounds robust?  Best-fit values from the generalized constraint: m_nu=0.556 pm 0.25 eV, n_eff=3.8pm0.4, and w=-1.058pm0.088 at 68% confidence level: firm lower limit on total neutrino mass, extra light degree of freedom, supports Lambda.  WL constraint helpful when w=-1 is of little help, once w is freed [?].  H0 dataset is advantageous over SNIa when w is fixed, in constraining n_eff.  As long as w is included as a free parameter, it is still the standardizable candles of SNIa that play the most dominant role in parameter constraints [of neutrinos?].

1210.2191
Calibrating Milky Way dust extinction using cosmological sources
Mortsell

Correlation between dust column density inferred from IR data and the observed colors of celectial objects at cosmological distances with small color dispersion, constrain the properties of MW dust.  Results from colors of quasars, BCGs and LRGs are broadly consistent, indicating a proportionality constant between the reddening E(B-V)=A_B-A_V and the dust column density D^T MJy/sr of p=E(B-V)/D^T=0.02 and a reddening parameter R_V=A_V/E(B-V)=3 with fractional uncertainties of the order 10%.  The data does not provide any evidence for spatial variations in the dust properties, except for a possible hint of scatter in the dust extinction properties at the longest optical wavelengths.

1210.2194
Neutrino masses and cosmological parameters from a Euclid-like survey: Markov Chain Monte Carlo forecasts including theoretical errors
Audren, Lesgourgues, Bird, Haehnelt, Viel

Forecasts of accuracy to determine parameters of minimal cosmological model and total neutrino mass based on combined mock data for a future Euclid-like galaxy survey and Planck.  (i) Spec-z survey and (ii) cosmic shear survey considered.  Use MCMC, assume two sets of theoretical errors.  The first error is meant to account for uncertainties in the modeling of the effect of neutrinos on the NL galaxy PS, and assume thsi error to be fully correlated in Fourier space.  The second error is meant to parameterize the overall residual uncertainties in modelling the NL galaxy PS at small scales, and is conservatively assumed to be uncorrelated and to increase with the ratio of a given scale to the scale of NL.  It hence increases with wavenumber and decreases with redshift.  With these two assumptions for the errors and assuming further conservatively that the uncorrelated error rises above 2% at k=0.4 h/Mpc and z=0.5, we find that a future Euclid-like cosmic shear/galaxy survey achieves a 1-sigma error on Mnu close to 32/25 meV, sufficient for detecting the total neutrino mass with good significance.  If the residual uncorrelated errors indeed rises rapidly towards smaller scales in the NL regime as we have assumed here, then the data on NL scales does not increase the sensitivity to the total neutrino mass.  ....

1210.2250
Residual foreground contamination in the WMAP data and bias in non-Gaussianity estimation
Chingangbam, Park

Analyze whether there is FG contamination in the cleaned WMAP7 data for Q, V and W.  A major fraction of the observed non-Gaussian deviation comes from residual FG contamination, as seen from added estimated contaminant fraction to simulated Gaussian CMB maps.  Compute non-Gaussian deviations of Minkowski Functionals after applying the point sources mask of Schodeller+ and find a decrease in the overall amplitudes of the deviations which is consistent with a decrease in the level of contamination.  

1210.2362
Cosmic evolution of star-formation enhancement in close major-merger galaxy pairs since z=1
Xu, ... Cooray, ... et al

See SF enhancement induced by gg interaction, by comparing IR luminosities to well-matched control samples.  SFG in SFG+SFG pairs in 0.6<z<1 are consistent with no SF enhancement.  SFGs in S+S pairs in a lower redshift bin of 0.2<z<0.6 show marginal evidence for a weak SF enhancement.  Significant and strong sSFR enhancement shown by SFGs in local sample of S+S pairs (prior results).  Results reveal a trend for SF enhancement in S+S pairs to decrease with increasing redshift.  Between z=0 and z=1, this decline of interaction-induced SF enhancement occurs in parallel with the dramatic increase (~10x) of the sSFR of single SFGs.  Both can be explained by the higher gas fraction in higher z disks.  SFGs in mixed pairs (S+E pairs) do not show any significant SF enhancement at any z.  The difference between SFGs in S+S pairs and in S+E pairs suggests a modulation of the sSFR by the inter-galactic medium IGM in the DM Hosting hosting these pairs.