Day 615

Thursday.

1403.6469
Satellite masses compared to LCDM subhaloes
Tollerud, Boylan-Kolchin, Bullock

Compare the kinematics of M31's satellite galaxies to the mass profiles of the sub haloes they are expected to inhabit in LCDM.  Consider the most massive sub haloes of an approximately M31-sized halo, following the assumption of a monotonic galaxy luminosity-to-subhalo mass mapping.  While this abundance matching relation is consistent with the kinematic data for galaxies down to the luminosity of the bright satellites of the MW and M31, it is not consistent with kinematic data for fainter dwarf galaxies (those with L<~1e8 Lsun).  Comparing the kinematics of M31's dSph satellites to the sub haloes reveals that M31's dSph satellites are too low density to be consistent with the sub haloes' mass profiles.  A similar discrepancy has been reported between MW dSphs and their predicted sub haloes, the "too big to fail" problem.  By contrast, total mass profiles of the dwarf Elliptical (and similarly bright) satellites are consistent with the sub haloes.  However, they suffer from large systematic uncertainties in their DM content because of substantial (and potentially dominant) contributions from baryons within their half-light radii.

1403.6470
Evidence of very low metallicity and high ionization state in a strongly lensed, star-forming dwarf galaxy at z=3.417
Amorin et al

Investigate the gas-phase metallicity and Ly continuum escape fraction of a SL, extreme emission-line galaxy at z=3.417 in CANDELS.  Derive ionization and metallicity sensitive emission-line ratios from H+K band medium resolution spectroscopy.  The galaxy shows high ionization conditions, as evidenced by its enhanced [OIII]/[OII] and [OIII]/Hbeta ratios.  Consistently, strong-line methods based on the available line ratios suggest that this galaxy is an extremely metal-poor galaxy, with a metallicity of 12+log(O/H)<7.44 (<5% solar), placing it among the most metal-poor SF galaxies at z>3 discovered so far.  In combination with its low stellar mass (2e8 Msun) and high SFR (5 Msun/yr), the metallicity of this galaxy is consistent with the extrapolation to low masses of the mass-metallicity relation traced by Ly-break galaxies at z>3, but it is 0.55 dex lower than predicted by the fundamental metallicity relation at z<2.5.  These observations suggest the picture of a rapidly growing galaxy, possibly fed by the massive accretion of pristine gas.  Additionally, deep LBT/LBC in the UGR bands are used to derive a limit to the LyC escape fraction, thus allowing exploration of sub-L* galaxies at z>3.  Find a 1 sigma upper limit to the escape fraction of 23%, which adds a new observational constraint to recent theoretical models predicting that sub-L* galaxies at high-z have high escape fractions and thus are responsible for the reionization of the Universe.

1403.6591
Statistical properties of filaments in weak gravitational lensing
Higushi, Oguri, Shirasaki

Study WL properties of filaments that connect clusters of galaxies through large N-body sims.  Select 4k halo pairs with masses higher than 1e14 Msun/h from the simulations and investigate DM distributions between two haloes with ray-tracing simulations.  In order to classify filament candidates, estimate convergence profiles and perform profile fitting.  Find that matter distributions between haloes can be classified in a plane of fitting parameters, which allow selection of staring filaments from the ray-tracing simulations.  Also investigate statistical properties of these filaments, finding them to be consistent with previous studies.  Find that 35% of halo pairs possess strain filaments, 4% of which can directly be detected at S/N>2 with WL.  Furthermore, study statistical properties of haloes at the edges of filaments. Find that haloes are preferentially elongated along filamentary structures and are less massive with increasing filament masses.  However, the dependence of these halo properties on masses of straight filaments is weak.

1403.4932
The assembly histories of quiescent galaxies since z=0.7 from absorption line spectroscopy
Choi, Conroy, Moustakas, Graves, … Brown, van Dokkum, et al

Present results from modeling the optical spectra of a large sample of quiescent galaxies between 0.1<z<0.7 from SDSS and the AGN and AGES.  Examine how the stellar ages and abundance patters of galaxies evolve over time as a function of stellar mass from 1e9.6-11.8 Msun.  Galaxy spectra are stacked in bins of mass and redshift, and modeled over a wavelength range from 4000A to 5500A.  Full spectrum stellar population synthesis modeling provides estimates of the age and the abundances of the elements Fe, Mg, C, N, and Ca.  Find negligible evolution in elemental abundances at fixed stellar mass over roughly 7 Gyr of cosmic time.  In addition, the increase in stellar ages with time for massive galaxies is consistent with passive evolution since z=0.7.  Taken together, these results favor a scenario in which the inner ~0.3-3 Re of massive quiescent galaxies have been passively evolving over the last half of cosmic time.  Interestingly, the derived light-weighted ages are considerably younger than the age of the Universe at all epochs, suggesting an effective single-burst SF epoch of z<1.5.  These young stellar population ages coupled with the existence of massive quiescent galaxies at z>1 indicate the inhomogeneous nature of the z<0.7 quiescent population.  The data also permit the addition of newly-quenched galaxies at masses below ~1e10.5 Msun at z<0.7.  Additionally, analyze very deep Keck DEIMOS spectra of the two brightness quiescent galaxies in a cluster at z=0.83.  There is tentative evidence that these galaxies are older than their counterparts in low density environments.  In an Appendix, demonstrate that the full spectrum modeling technique allows for accurate and reliable modeling of galaxy spectra to low S/N and/or low spectral resolution
1403.4936
Predictions for microlensing planetary events from core accretion theory
Zhu, Penny, Mao, Gould, Gendron

Conduct the first microlensing simulation in the context of planet formation model.  THe planet population is taken from the Ida&Lin core accretion model of 0.3 Msun stars.  with 6690 microlensing events, find for a simplified Korea Microlensing Telescopes Network (KMTNet) the fraction of planetary events is 2.9%, out of which 5.8% show multiple-planet signatures.  The number of super-Earths, super-Neptunes and super-Jupiters detected are expected to be almost equal.  Simulation shows that high-magnification events and massive planets are favored by planet detections, which is consistent with previous expectation.  However, notice that extremely high-magnification events are less sensitive to planets, which is possibly because the 10 min sampling of KMTNet is not intensive enough to capture the subtle anomalies that occur near the peak.  This suggests that while KMTNet observations can be systematically analyzed without reference to any follow-up data, follow-up observations will be essential in extracting the full science potential of very high-magnification events.  The uniformly high-cadence observations expected for KMTNet also result in ~55% of all detected planets being non-caustic-crossing, and more low-mass planets even down to Mars-mass being detected via planetary caustics.  Also find that the distributions of orbital inclinations and planet mass ratios in multiple-planet events agree with the intrinsic distributions.

1403.4947
Relativistic weak lensing from a fully non-linear cosmological density field
Thomas, Bruni, Wands

In WL, observables are computed by ray-tracing through Newtonian N-body simulations, taking into account solely the Newtonian potential.  This has not previously been shown to be valid on non-linear scales.  Examine WL on NL scales and show that there are Newtonian and relativistic contributions, and that the latter can also be extracted from standard Newtonian simulations.  Use the post-Friedmann formalism, a post-Newtonian type framework for dealing with relativistic effects in the universe on all scales, to derive the full WL deflection angle valid on NL scales.  Deflection angle includes terms that are quadratic in the first order deflection, the first post-Newtonian corrections to the two scalar gravitational potentials and the effects of the vector and tensor contributions to the metric.  Show that the only contributing term that is quadratic in the first order deflection is the expected Born correction and lens-lens coupling term.  This deflection angle is valid for any metric theory of gravity.  The strength of this approach is that the form of the metric is well motivated, and the metric components are clearly related to the matter content once the gravitation theory has been specified.  Thus, specifying GR, write down a complete set of equations for a GR LCDM universe for computing all of the possible lensing terms from Newtonian N-body simulations.  Illustrate this with the vector potential and show that, in a LCDM universe, its contribution to the E-mode is negligible with respect to that of the Newtonian scalar potential, even on NL scales.  Thus, under the standard assumption that Newtonian N-body sims give a good approximation of the matter dynamics, this paper validates the standard ray tracing approach for a LCDM cosmology.

1403.5173
Complementarity of neutrino less double beta decay and cosmology
Dodelson, Lykken

Neutrinoless double beta decay experiments constrain one combination of neutrino parameters, while cosmic surveys constrain another.  This complementarity opens up an exciting range of possibilities.  If neutrinos are Majorana particles, and the neutrino masses follow an inverted hierarchy, then the upcoming sets of both experiments will detect signals.  The combined constraints will pin down not only the neutrino masses but also constrain one of the Majorana phases.  If the hierarchy is normal, then a beta decay detection with the upcoming generation of experiments is unlikely, but cosmic surveys could constrain the sum of the masses to be relatively heavy, thereby producing a lower bound for the neutrino less double beta decay rate, and therefore an argument for a next generation beta decay experiment.  In this case, a combination of the phases will be constrained.

1403.5231
Steps to reconcile inflationary tensor and scalar spectra
Miranda, Hu, Adshead

The recent BICEP2 B-mode polarization determination of an inflationary tensor-scalar ratio r=0.2 is in tension with simple scale-free models of inflation due to a lack of a corresponding low multipole excess in the temperature PS which places a limit of r<0.11 (95% CL) on such models.  Single-field inflationary models that reconcile these two observations, even those where the tilt runs substantially, introduce a scale into the scalar PS.  To cancel the tensor excess, and simultaneously explain the excess already present in LCDM, ideally the model should introduce this scale as a relatively sharp transition in the tensor-scalar ratio around the horizon at recombination.  Consider models which generate such a step in this quantity and find that they can improve the joint fit to the temperature and polarization data by up to 2 Delta ln L~-17 without changing cosmological parameters.  Precision E-mode polarization measurements should be able to test this explanation.

1403.5237
J-PAS: The Javalambre-Physics of the Accelerated Universe Astrophysical Survey
Benitez, et al

J-PAS is a narrow-band, very wide field cosmological survey to be carried out in Spain with a purpose-built, dedicated 2.5m telescope and a 4.7 sq. deg camera with 1.2 Gpix.  Starting in late 2015, J-PAS will observe 8500 sqdeg of the Northern Sky and measure 0.003(1+z) photo-z for 9e7 LRG and ELG galaxies plus several million QSOs, sampling an effective volume of ~14 Gpc^3 up to z=1.3 and becoming the first radial BAO experiment to reach Stage IV.  J-PAS will detect 7e5 galaxy clusters and groups, seeing constraints on DE which rival those obtained from its BAO measurements.  Thanks to the superb characteristics of the site (seeing ~0.7"), J-PAS is expected to obtain a deep, sub-arcsec image of the Northern sky, which combined with its unique photo-z precision will produce one of the most powerful cosmological lensing surveys before the arrival of Euclid.  J-PAS unprecedented spectral time domain information will enable a self-contained SN survey that, without the need for external spectroscopic follow-up, will detect, classify and measure sigma_z~0.5% redshifts of ~4000 SNeIa and ~900 core-collapse SNe.  The key to the J-PAS potential is its innovative approach: a contiguous system of 54 filters with 145 A width, placed 100 A apart over a multi-degree FoV is a powerful "redshift machine", with the survey speed of a 4000 multiplexing low resolution spectrograph, but many times cheaper and much faster to build.  The J-PAS camera is equivalent to a 4.7 sqdeg IFU and it will produce a time-resolved, 3d image of the Northern Sky with a very wide range of Astrophysical applications in Galaxy Evolution, the nearby universe and the study of resolved stellar populations.