Day 514

Tuesday.

1309.5363
Dynamical measurements of the interior structure of Exoplanets
Becker, Batygin

Giant gaseous planets often reside on orbits in sufficient proximity to their host stars for the planetary quadrupole gravitational field to become non-negligible.  In presence of an additional planetary companion, a precise characterization of the system's orbital state can yield meaningful constraints on the transiting planet's interior structure.  However, such methods can require a very specific type of system.  This paper explores the dynamic range of applicability of these methods and shows that interior structure calculations are possible for a wide array of orbital architectures.  The HAT-P-13 system is used as a case study, and the implications of perturbations arising from a third distant companion on the feasibility of an interior calculation are discussed.  Find that the method discussed here is likely to be useful in studying other planetary systems, allowing the possibility of an expanded survey of the interiors of exoplanets.  [how are these constraints different from what we find from, say, Jupiter, which is not in close proximity to the Sun?]

1309.5380
Facilities for dark energy investigations
Weinberg, Bard, Dawson, Dore, Frieman, Gebhardt, Levi, Rhodes

[Snowmass paper.] Summarizes some of the major ongoing and planned dark energy experiments, focusing on those in which the US community has a leading or significant supporting role [thus KiDS is not included...].  Provides background information for other reposrt from the "Dark Energy and CMB" working group of the APS division of Particlse and Fields long-term planning exercise.  Provide 1-2 page summaries of BOSS (SDSS-III) and eBOSS (SDSS-IV), DES, HSC, and PSF (Prime Focus Spectrograph), HEDTEX, DESI, LSST, Euclid and WFIRST.  Over the next one to two decades, these experiments seek to improve the precision of measurements of the cosmic expansion history and cosmic structure growth by factors of 10-100, while simultaneously increasing their redshift range and tightening control and cross-checks of systematic effects.  These measurements will dramatically improve the empirical constraints on theoretical explanations of cosmic acceleration and could lead to breakthroughs in the understanding of the nature of gravity and spacetime or the forms of energy present in the future.

1309.5381
Inflation physics from the cosmic microwave background and large scale structure
Abazajian et al

[Snowmass paper.] Fluctuations in the intensity and polarization of the CMB and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time.  The next generation of CMB and LSS experiments are poised to test the leading paradigm for these earliest moments---the theory of cosmic inflation--and to detect the imprints of the inflationary epoch, thereby dramatically increasing our understanding of fundamental physics and the early universe.  A future CMB experiment with sufficient angular resolution and frequency coverage that surveys at least 1% of the sky to a depth of 1 uK-arcmin can deliver a constraint on the tensor-to-scalar ratio that will either result in a 5-sigma measurement of the energy scale of inflation or rule out all large-field inflation models, even in the presence of foregrounds and the gravitational lensing B-mode signal.  LSS experiments, particularly spectroscopic surveys such as the DESI, will complement the CMB effert by improving current constraints on running of the spectral index by up to a factor of four, improving constraints on curvature by a factor of ten, and providing non-Gaussianity constraints that are competitive with the current CMB bounds.

1309.5382
Distance probes of dark energy
Kim, Padmanabhan, Aldering, Allen, Cahn, D'Andrea, Dalal, Dawson, Denney, Eisenstein, Filey, Freedman, Ho, Holz, Kend, Kasen, ..., Linder, et al

Present results from the Distances subgroup of he Cosmic Frontier Community Planning Study (Snowmass 2013).  Summarize the current state of the field as well as future prospects and challenges.  In addition to the established probes using SNe Ia and BAO, also consider prospective methods based on clusters, AGN, gravitational wave sirens and SL time delays.

1309.5383
Neutrino physics from the cosmic microwave background and large scale structure
Abazajian, ... Das, Devlin, ... et al

Report on the status and prospects of the quantification of neutrino properties through the cosmological neutrino background for Snowmass long-term planning exercise.  Experiments planned and underway are prepared to study the cosmological neutrino background in detail via its influence on distance-redshift relations and the growth of structure.  The program for the next decade described in this document, including upcoming spectroscopic galaxy surveys eBOSS and DESI and a new Stage-IV CMB polarization experiment CMB-S4, will achieve sigma(sum m_nu) = 16 meV and sigma(N_eff)=0.020.  Such a mass measurement will produce a high significance detection of non-zero sum m_nu, whose lower bound derived from atmospheric and solar neutrino oscillation data is about 58 meV.  If neutrinos have a minimal normal mass hierarchy, this measurement will definitely rule out the inverted neutrino mass hierarchy, shedding light on one of the most puzzling aspects of the standard model of particle physics --- the origin of mass.  This precise measurement of N-eff will allow for high sensitivity to any light and dark degrees of freedom produce in the big band and a precision test of the standard cosmological model predication that N_eff=3.046.

1309.5384
Spectroscopic needs for imaging dark energy experiments: photometric redshift training and calibration
Newman, Abate, Abdalla, ... et al

[Another Snowmass paper.]  Large sets of objects with spectroscopic redshift measurements will be needed for imaging DE experiments to achieve their full potential, serving two goals: "training"; i.e., the use of objects with known redshift to develop and optimize photometric z algorithms; and "calibration", i.e., the characterization of moments of redshift (or photo-z error) distributions.  Better training makes cosmological constraints from a given experiment stronger, while highly-accurate calibration is needed for photo-z systematics not to dominate errors.  In this white paper, investigate the required scope of spectroscopic datasets which can serve both these purposes for ongoing and next-generation DE experiments, as well as the time required to obtain such data with instruments available in the next decade.  Large time allocations on kilo-object spectrographs will be necessary, ideally augmented by IR spectroscopy from space.  Alternatively, precision calibrations could be obtained by measuring cross-correlation statistics using samples of bright objects from a large baryon acoustic oscillation experiments such as DESI.  Also summarize the additional work on photometric redshift methods needed to prepare for ongoing and future DE experiments.

1309.5385
Growth of cosmic structure: probing dark energy beyond expansion
Huterer et al

[Snowmass] The quantity and quality of cosmic structure observations have greatly accelerated in recent years.  Further leaps forward will be facilitated by imminent projects, which will enable mapping of the evolution of dark and baryonic matter density fluctuations over cosmic history.  The way that these fluctuations vary over space and time is sensitive to the nature of DM and DE.  DE and gravity both affect how rapidly structure grows; the greater the acceleration, the more suppressed the growth of structure, while the greater the gravity, the more enhanced the growth.  While distance measurements also constrain DE, the comparison of growth and distance data tests whether GR describes the laws of physics accurately on large scales.  Modified gravity models are able to reproduce the distance measurements but at the cost of altering the growth of structure (these signatures are described in more detail in the accompanying paper on Novel Probes of Gravity and Dark Energy [see below]).  Upcoming surveys will exploit these differences to determine whether the acceleration of the Universe is due to dark energy or to modified gravity.  To realize this potential, both wide field imaging and spectroscopic redshift surveys play crucial roles.  Projects including DES, eBOSS, DESI, PFS, LSST, Euclid, and WFIRST are in line to map more than a 1000 cubic-billion-light-year volume of the Universe.  THese will map the cosmic structure growth rate to 1% in the redshift range 0<z<2, over the last 3/4 of the age of the Universe.

1309.5386
Dark Energy and CMB
Dodelson et al

[Snowmass summary paper.]  This paper summarizes the findings of the other papers, all of which have been submitted jointly to the arXiv.

1309.5389
Novel probes of gravity and dark energy
Jain et al

[Snowmass paper.]  Last decade has seen advances in theories that go beyond smooth DE--modified gravity and interactions of DE.  While the theoretical terrain is being actively explored, the generic presence of fifth forces and dark sector coupling suggests a set of distinct observational signatures.  This report focuses on observations that differ from the conventional probes that map the expansion history or large-scale structure.  Examples of such novel probes are: detection of scalar fields via lab experiments, test of modified gravity using stars and galaxies in the nearby universe, comparison of lensing and dynamical masses of galaxies and clusters, and the measurements of fundamental constants at high redshift.  The observational expertise involved is very broad as it spans laboratory experiments, high resolution astronomical imaging and spectroscopy and radio observations.  IN the coming decade, searches for these effects have the potential for discovering fundamental new physics.  Discuss how the searches can be carried out using experiments that are already under way or with modes adaptations of existing telescopes or planned experiments.  The accompanying paper on the Growth of Cosmic Structure describes complementary tests of gravity with observations of large-scale structure.

1309.5408
The stellar and dark matter distributions in elliptical galaxies from the ensemble of strong gravitational lenses
Oguri, Rusu, Falco

Derive the average mass profile of elliptical galaxies from the ensemble of 161 SL selected from several surveys, assuming that the mass profile scales with the stellar mass and effective radius of each lensing galaxy.  The total mass profile is well fitted by a power-law \rho(r) propto r^gamma with best-fit slope gamma =-2.11pm0.05.  The decomposition of the total mass profile into stellar and DM distributions is difficult due to a fundamental degeneracy between the stellar IMF and the DM fraction f_DM.  Demonstrate that this IMF-f_DM degeneracy can be broken by adding direct stellar mass fraction measurements by quasar microlensing observations.  The best-fit model prefers the Salpeter IMF over the Chabrier IMF, and a smaller central DM fraction than that predicted by adiabatic contraction models.

1309.5448
A deep search for molecular gas in two massive Lyman break galaxies at z=3 and 4: vanishing CO-emission due to low metallicity?
Tan et al

Search for CO emission toward 2 massive, non-lensed LBGs at z=3.2 and 4.0.  Find that CO lines are >3-4 times weaker than expected based on the relation between IR and CO luminosities followed by similarly, massive galaxies at z=0-2.5.  This is consistent with a scenario in which these galaxies have low metallicity, causing an increased CO-to-H_2 conversion factor, i.e., weaker CO-emission for a given molecular (H_2) mass.  The required metallicities at z>3 are lower than predicted by the fundamental metallicity relation at these redshifts, consistent with independent evidence.  Unless the galaxies are atypical in this respect, detecting molecular gas in normal galaxies at z>3 may thus remain challenging even with ALMA.

1309.5532
Mock galaxy catalogs using the quick particle mesh method
White, Tinker, McBride

Sophisticated analysis of modern large-scale structure surveys requires mock catalogs.  Mock catalogs are used to optimize survey design, test reduction and analysis pipelines, make theoretical predictions for basic observables and propagate errors through complex analysis chains .  Present a new method, "quick particle mesh", for generating many large-vlume, approximate mock catalogs at low computational cost.  The methods is based on using rapid, low-resolution particle mesh simulations that accurately reproduce the large-scale DM density field.  Particles are sampled from the density field based on their local density such that they have N-point statistics nearly equivalent to the haloes resolved in high-resolution simulations, creating a set of mock haloes that can be populated using halo occupation methods to create galaxy mocks for a variety of possible target classes.

1309.5556
Galaxy and mass assembly (GAMA): improved cosmic growth measurements using multiple tracers of large-scale structure
Blake et al

Present the first application of a "multiple-tracer" RAD analysis to an observational galaxy sample, using data from GAMA.  Dataset: r<19.8 magnitude-limited sample of 178,579 galaxies of z<0.5 and an area of 180 sq deg.  Obtain 10-20% improvements in measurements of gravitational growth rate compared to a single-tracer analysis, deriving from the correlated sample variance imprinted in the distributions of the overlapping galaxy populations.  Present new expressions for the covariances between the auto-power and cross-power spectra of galaxy samples that are valid for a general survey selection function and weighting scheme.  Find no evidence for a systematic dependence of the measured growth rate on the galaxy tracer used, justifying the RSD modeling assumptions, and validate results using mack catalogues from N-body simulations.  For multiple tracers selected by galaxy color, measure normalized growth rates in 2 independent redshift bins f*sigma_8(z=0.18) =0.36 pm 0.09 and f*sigma_8(z=0.38)=0.44pm0.06, in agreement with standard GR gravity and other galaxy surveys at similar redshifts.

1309.5718
Weak lensing galaxy cluster field reconstruction
Jullo, Piers, Jauzac, Kneib

In this paper, compare three methods to reconstruct galaxy cluster density fields with WL data.  The first method called FLens integrates an inpainting concept to inver the shear field with possible gaps, and a multi-scale entropy denoising procedure to remove the noise contained in the final reconstruction, that arises mostly from the random intrinsic shape of the galaxies.  The second and third methods are based on an model of the density field made of a multi-scale grid of radial bases functions.  In one case, the model parameters are computed with a linear inversion involving a singular value decomposition.  In the other case, the model parameters are estimated using a Bayesian MCMC optimization implemented in the lensing software Lenstool.  Methods are compared on simulated data with varying galaxy density fields.  Pay particular attention to the errors estimated with resampling.  FInd the multi-scale grid model optimized with MCMC to provide the best results, but at high computational cost, especially when considering resampling.  The FLens method is a good compromise with fast computation, high signal to noise reconstruction, but lower resolution maps.  All three methods are applied to the MACS J0717+3745 galaxy cluster field, and reveal the filamentary structure discovered in Jauzac et al. 2012.  Conclude that sensitive priors can help to get high signal to noise, and unbiased reconstructions.