1211.2232
A fast method for power spectrum and foreground analysis for 21 cm cosmology
Dillon, Liu, Tegmark
Acceleration of the Lie & Tegmark quadratic estimator formalism for inverse variance foreground subtraction and PS estimation in 21 cm tomography from O(N^3) to O(N log N), where N is the number of voxels of data. Megavoxel scale analysis feasible for radio interferometery survey; makes "only" moderately restrictive assumptions about FG models and survey geometry. Exploit iterative and MC techniques and symmetries of the FG covariance matricies to quickly estimate the 21cm brightness temperature PS, p(k_parallel, k_perp), the Fisher information matrix, the error bars, the window functions, and the bias. Also extend the Liu & Tegmark FG model to include bright point sources with known positions that scales as O[(N log N) (N pt sources)] < O(N^5/3). First application: forecast error bars and window functions for Murchinson Widefield Array (128-tile); show 1000 hrs of observations should be sufficiently sensitive to detect the PS signal from the epoch of reionization.
1211.2274
Power spectrum precision for redshift space distortions
Linder, Samsing
What accuracy do z-space distortions need to be modeled in order not to unduly bias cosmological conclusions. Fitting for NL and z-space corrections to the linear theory real space density PS in bins in wavemode, analyze both the effect of marginalizing over these corrections and of the bias due to not correcting them fully. While naively subpercent accuracy is required to avoid bias in the fixed case, in the fitting approach the Kwan-Lewis-Linder reconstruction function for z-space distortions is found to be accurately self-calibrated with little degredation in DE and gravity parameter estimation for a next generation galaxy z-survey such as BigBOSS.
1211.2317
The stellar populations of massive galaxies in the local universe
McDermid
A brief review of stellar population properties of massive galaxies, focusing on early-type galaxies in particular, with emphasis on recent results from ATLAS3D survey. Occurrence of young stellar ages, cold gas, and ongoing SF in E-type galaxies gives important clues to the evolutionary path of these galaxies. Empirical SFHs gives a meaningful picture of galaxy stellar population properties, and allows accurate comparison of mass estimates from populations and dynamics. Provides a strong evidence of a non-universal IMF. Distinct components within galaxies, to spatial structures seen: spatially-resolved studies of stellar populations. Stellar populations in the faint outer envelopes of early-type galaxies promise to put constraints on the ratio of accreted stellar mass versus that formed 'in situ' - a key feature of recent galaxy formation models (although they are difficult to observe). Galaxy environment appears to play a key role in controlling the stellar population properties of low mass galaxies. Simulations reminds that current day galaxies are the product of a complex assembly and environment history, which gives rise to the trends that we see: strong implications for interpretation of environmental trends.
1211.2382
A new galactic extinction map in high ecliptic latitudes
Kohyama, SHibai, Fukagawa, Sumi, Hibi
New SFD galactic extinction map at 5' spatial resolution, for beta > 30 deg. SFD had 1 deg resolution. Compare with SFD, spatial resolution difference significant. Derived from FIR emission, better than 2MASS-derived map.
1211.2457
Probing gravitation with pulsars
Kramer
Radio pulsars ad precise cosmic clocks: concentrate on the usage of pulsars as gravity labs.
1211.2475
The ongoing pursuit of R Coronae Borealis stars: ASAS-3 survey strikes again
Tisserand et al
* R Coronae Borealis: a class of yellow giant variable stars that suddenly fade (non-periodic) in the optical (but not in the IR). It is thought that carbon in the photosphere or the outer region of the star suddenly condenses into soot, and thereby blocking the optical wavelength.
RCBs are rare, H-deficient, C-rich supergiant variable stars that are likely the evolved merger products of pairs of CO and He WDs. ...
1211.2510
Inclination-dependent AGN flux profiles from strong lensing of the Kerr space-time
Chen, Dai, Baron
X-ray emission sizes of quasars to be about 10 gravitational radii, one order of magnitude smaller than the optical emission sizes. Use ray-tracing code for Kerr space-time. The SL X-ray-to-optical magnification ratio can change by a factor of ~10 for normal quasars in some cases, and another factor of ~10 for BALs and obscured quasars.
1211.2590
The expansion of the universe observed with supernovae
Astier
Review: principle and difficulties of the measurements, the classification and diversity of SNe, and the physics of the explosion. Systematic uncertainties (photometric calibration). Major SNe cosmology survey, analysis and conclusions, and the present status of the field.
1211.2616
Baryon acoustic oscillations in the Ly-\alpha\ forest of BOSS quasars
Busca et al
Detection of BAO feature in the 3d correlation function in the Lya forest high-z quasars. Use 48k quasars at 2.1<z<3.5 from SDSS-BOSS. Mean z = 2.3; measure monopole and quadrupole components of the correlation function for separations in the range 20<r<200 Mpc/h. A peak in the correlation function is seen at a separation equal to 1.01x the distance expected for the BAO peak within a concordance LCDM cosmology. The first detection of the BAO peak at high z results in constraints on the angular diameter distance da and the expansion rate H at z=2.3 that, by themselves, require the existence of DE. Combined with CMB observations, this results implies H(z=2.3)=224. km/s/Mpc, indicating that the time derivative of the cosmological scale parameter a dot is significantly greater than that measured with BAO at z~0.5. This demonstrates that the expansion was decelerating in the range 0.7<z<2.3, as expected from the matter domination during this epoch. Combined with measurements of H0, one sees the pattern of deceleration followed by acceleration characteristic of a DE dominated universe.
1211.2638
A census of orbital properties of the M31 satellites
Watkins, Evans, van de Ven
Analysis of the dynamics of the M31 satellite system (statistical analysis of the proper motion for all except two). Many associated infalls; orbital analysis.
1211.2666
Early stages of cluster formation: fragmentation of massive dense cores down to ~1000 AU
Palau et al
Observations of [stellar] cluster cradles at high resolution. High-velocity knots identified, aligned with previously known outflow directions. Additional cores from literature. Build a sample of 18 protoclusters with luminosities spanning 3 orders of magnitude. ~30% show no sign of fragmentation, while 50% split up into ~4 mm sources [wavelength? size?]. No correlation of total mass, mean density, bolometric luminosity. Compare to magneto-hydro sims; find that the low-fragmented regions are well reproduced in the magnetized core case, while the highly-fragmented regions are consistent with cores where turbulence dominates over the B-field. Overall, the study suggests that the fragmentation in massive dense cores could be determined by the initial B-field/turbulence balance in each particular core.
1211.2748
Spinning dust radiation: a review of the theory
Ali-Haimoud
Review: current stuatus of theoretical modeling of electric dipole radiation from spinning dust grains. Classical and quantum physics concepts; diverse processes involved. Rotational excitation and damping rates through various mechanisms discussed, as well as methods of computing the grain angular momentum distribution function. Assumptions on grain properties are reviewed. The robustness of theoretical predictions seems mostly limited by uncertainties regarding the grains themselves (abundance, dipole moments, size and shape distribution).
1211.2771
A simple prescription for simulating and characterizing gravitational arcs
Furlanetto et al
Present ArcEllipse: a simple prescription to create objects with shape similar to gravitational arcs. Also present PaintArcs: a code that couples this geometrical form with a brightness distribution and adds the resulting object to images. Finally, introduce ArcFitting: a tool that fits ArcEllipses to images of real gravitational arcs. Validate fitting technique using simulated arcs and apply it to CFHTLS and HST images of tangential arcs around clusters of galaxies. Recovers total signal in real images to 10-30% (assume Sersic profile of the source). Substructure can be seen in difference images between model and data.
1211.2797
CLASH: the enhanced lensing efficiency of the highly elongated merging cluster MACS J0416.1-2403
Zitrin et al
SL analysis of a merging cluster at z=0.42 in CLASH/HST observations. 70 new multiple images and candidates of 23 BG sources at 0.7<zphot<6.17, including two probably high-z dropouts, revealing a highly elongated lens with axis ratio ~5:1, and a major axis of 100' (z_s~2). Compared to other well-studied clusters, M0416 shows an enhanced lensing efficiency. Although the critical area is not particularly large (0.6 square arcmin), the number of multiple images, per critical area, is anomalously high. Calculate the observed elongation boosts the number of multiple images per critical area, by a factor of 2.5x, due to the increase ratio of the caustic area relative to the critical area. Additionally, find that the observed separation between the two main mass components enlarges the critical area by a actor of 2. These geometrical effects can account for the high number (density) of multiple images observed. Find in numerical simulations, only 4% of the clusters exhibit as elongated critical curves as M0416.
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