Day 441

Monday.

1306.1226
A dynamical signature of multiple stellar populations in 47 Tucanae
Richer, Heyl, ... etal

MS shows 47 Tuc contains multiple stellar populations.  Divide MS into 4 color groups, which presumably represent stars of various chemical compositions.  The kinematic properties of each of these groups in proper-motions exhibit strong signal of differing proper-motion anisotropies with differing MS color; bluest MS stars exhibit the largest proper-motion anisotropy, this becomes undetectable for the reddest stars.  The bluest stars are also the most centrally concentrated.  Similar analysis on SMC stars yields none of the anisotropy exhibited by 47 Tuc.  [isn't blue-red split a new-old split?  I guess not in this case]

1306.1230
Optimal non-linear transformations for large scale structure statistics
Carron, Szapudi

Logarithmic or Gaussianization transformation proposed to recapture information about the (Gaussian) IC; during NL evolution, part of the cosmologically relevant information leaks out from the second moment of the distribution.  This information is accessible only through complex higher order moments, or may become inaccessible to the hierarchy.  Investigate these transformations in the framework of Fisher information using cosmological perturbation theory of matter field with Gaussian IC.  Show that at each order in perturbation theory, there is a polynomial of corresponding order exhausting the information on a given parameter.  This polynomial can be interpreted as the Taylor expansion of the maximally efficient "sufficient" observable in the NL regime.  Determine explicitly this maximally efficient observable for local transformations.  This optimal transform is essentially the simple power transform with an exponent related to the slope of the PS; when this is -1, it is indistinguishable from log transform.  This transform Gaussianizes the distribution, and recovers the linear density contrast.  This a direct connection is revealed between undoing of the NL dynamics and the efficient capture of Fisher information.  Analytical results compared with measurements from MS; find that the transforms remain very close to optimal even in the deeply NL regime with sigma^2~10.

1306.1232
Constraints on spatial variations in the Fine-structure constant from Planck
O'Bryan, Smidt, De Bernardis, Cooray

Find no evidence for a spatially varying alpha at a redshift of 1000.

1306.1238
New image statistics for detecting disturbed galaxy morphologies at high redshift
Freeman, ... Newman, ... Koekemoer, et al

Testing theories of hierarchical structure formation requires estimating the distribution of galaxy morphologies and its change with z.  One aspect of this investigation involves IDing galaxies with disturbed morphologies (e.g., merging galaxies).  Done by associating particular statistic values with disturbance.  Introduce 3 statistics that enhance detection of disturbed morphologies at high-z (~2): the multi-mode (M), intensity (I), and deviation (D) statistics.  Show effectiveness by training a machine-learning classifier (random forest) using 1639 galaxies observed in the H band by WFC3, galaxies that had been previously classified by eye by the CANDELS collaboration.  Find that the MID statistics are the most useful for identifying disturbed morphologies.  Also explore whether human annotators are useful for IDing disturbed morphologies.  Demonstrate that they show limited ability to detect disturbance at high z, and that increasing their number beyond approximately 10 does not yield better classification performance.  Propose a simulation-based model-fitting algorithm that mitigates these issues by bypassing annotation.

1306.1272
Dark energy with gravitational lens time delays
Treu, Marshall, ... Fassnacht, Keeton, Linder, Moustakas, Bradac, ... Courbin, Dobler, ... Kochanek, Komatsu, Kppomans, ... Natarajan, Oguri, ... et al

[white paper from SNOWMASS 2013:] SL time delays are a powerful and cost effective probe of DE.  Recent studies have shown that a single lens can provide a distance measurement with 6-7% accuracy (including random and systematic uncertainties), provided sufficient data are available to determine the time delay and reconstruct the gravitational potential of the deflector.  Gravitational-time delays are a low redshift (z~0-2) probe and thus allow one to break degeneracies in the interpretation of data from higher-redshift probes like the CMB in terms of the DE EoS.  Current studies are limited by the size of the sample of known lensed quasars, but this situation is about the change.  SF imaging surveys are likely to discover 1000s of lensed quasars, enabling the targeted study of ~100 of these systems and resulting in substantial gains in the DE FoM.  A further order of mag improvement will be possible in the next decade with the 10k systems expected to be detected and measured with LSST and Euclid.  To fully exploit these gains, identify 3 priorities: (1) support for the development of SW required for the analysis of the data. (2) small robotic telescopes (1-4m diameter) dedicated to monitoring of lensed quasars will transform the field by delivering accurate time delays for ~100 systems.  (3) In the 2020's, LSST will deliver 1000s of time delays; the bottleneck will instead be the acquisition and analysis of high res imaging follow-up.  Thus the top priority for the next decade is to support fast high res imaging capabilities, such as those enabled by the James Webb Space Telescope and next gen adaptive optics systems on large ground based telescopes.  [Should they have published before Schneider & Sluse?]

1306.1518
Contamination of broad-band photometry by nebular emission in high redshift galaxies: Investigations with Keck's MOSFIRE near-infraed spectrograph
Schenker, Ellis, Konidaris, Stark

[Will affect the photo-z?]  High-z Ly-break galaxies: within certain z ranges, and especially at z~6-7, such lines may be strong enough to reduce estimates of the stellar masses and ages of galaxies compared to those derived assuming that broad-band photometry represents stellar light alone.  To test this hypothesis at the highest z where such lines can be probed with ground-based facilities, examine the NIR spectra of 20 Ly-break galaxies at 3.0<z<3.8 using the MOSFIRE at the Keck I telescope.  Use this data to derive the rest-frame EW of [OIII] emission and show that these are comparable to estimate derived using the SED fitting technique introduced for sources of known redshift by Stark et al (2013).  [so everything is ok?  No missing M*?  not very clear]  Although the current sample is modest, its [OIII] EW distribution is consistent with that inferred for Ha based on SED fitting of Star et al's larger sample of 3.8<z<5 galaxies.  For a subset of survey galaxies, use the combination of optical and NIR spectroscopy to quantify kinematics of outflows in z~3.5 SF galaxies, and discuss the implications for reionization measurements.  The trends underline the dangers of relying purely on broad-band photometry to estimate the physical properties of high z galaxies and emphasize the important role of diagnostic spectroscopy.