Day 504

Monday.

1309.1466
Star - Planet - Debris disk alignment in the HD 82943 system: is planetary system coplanarity actually the norm?
Kennedy, et al

Recent results suggest that the two planets in the HD 82943 system are inclined to the sky plane by 20 pm 4 deg.  Show that the debris disk in this system is inclined by 27 pm 4 deg, thus adding strength to the derived planet inclinations and suggesting that the planets and debris disk are consistent with being aligned at a level similar to the Solar System.  The stellar equator is inferred to be inclined by 28 pm 4 deg, suggesting that the entire star-planet-disk system is aligned, the first time such alignment has been tested for radial velocity discovered planets on ~AU wide orbits.  Show that the planet-disk alignment is primordial, and not the result of planetary secular perturbations to the disk inclination.  In addition, note 3 other systems with planets at >10 AU discovered by direct imaging that already have good evidence of alignment, and suggest that empirical evidence of system-wide star-planet-disk alignment is therefore emerging, with the exception of systems that host hot Jupiters.  While this alignment needs to be tested in a larger number of systems, and is perhaps unsurprising, it is a reminder that the system should be considered as a whole when considering the orientation of planetary orbits.

1309.1477
Observational requirements for Lyman-alpha forest tomographic mapping of large-scale structure at z~2
Lee (KG), Hennawi, White (Martin), Croft, Ozbek

The z>2 Lya forest traces the underlying DM distribution on large scales and, given sufficient sightlines, can be used to create 3d maps of LSS.  Examine the observational requirements to construct such maps and estimate the S/N as a function of exposure time and sightline density.  Sightline densities at z=2.25 are n_los = 360, 1200, 3300 deg^-2 at limiting magnitudes of g=24.0, 24.5, 25.0, resulting in transverse sightline separations of d_perp=3.6, 1.9, 1.2 Mpc/h, which roughly sets the reconstruction scale.  Simulate these reconstructions using mock spectra with realistic noise properties, and find that spectra with S/N=4 per angstrom can be used to generate maps that clearly trace the underlying DM at overdensities of rho/<rho>~1.  For the VLT/VIMOS spectrograph, exposure times t_exp=4,6,10 hrs are sufficient for maps with spatial resolution epsilon_3d=5.0, 3.2, 2.3 Mpc/h.  Assuming ~250 Mpc/h is probed along the LoS, 1 deg^2 of survey area would cover a comoving volume of ~1e6 (Mpc/h)^3 at <z>=2.3, enabling efficient mapping of large volumes with 8-10m telescopes.  These maps could be used to study galaxy environments, detect proto-clusters, and study the topology of large-scale structure at high-z.

1309.1579
Bispectrum from open inflation
Sugimura, Komatsu

Calculate the bispectrum of primordial curvature perturbations, zeta, generated during "open inflation".  Inflation occurs inside a bubble nucleated via quantum tunneling from the BG false vacuum state.  Our universe lives inside the bubble, which can be described as a Friedman-Lemaitre-Robertson-Walker (FLRW) universe with negative spatial curvature, undergoing slow-roll inflation.  Pay special attention to the issue of an initial state for quantum fluctuations.  A "vacuum state" defined by a positive-frequency mode in the de Sitter space charted by open coordinates is different from the Euclidean vacuum (which is equivalent to the so-called "Bunch-Davies vacuum").  Quantum tunneling then modifies the initial state away from the original Euclidean vacuum.  While most of the previous study on modifications of the initial quantum state introduces, by hand, an initial time at which the quantum state is modified as well as the form of the modification, an effective initial time naturally emerges and the form is fixed by quantum tunneling in open inflation models.  THerefore, open inflation enables a self-consistent computation of the effect of a modified initial state on the bispectrum.  Find a term which goes as <zeta_k1 zeta_z2 zeta_k3> propto 1/k1^2 k3^4 in the so-called squeezed configurations, k3 || k1 approx k_2, in agreement with the previous study.  The bispectrum in the exact folded limit, e.g., k1=k2+k3, is also enhanced and remains finite.  However, these terms are exponentially suppressed when the wavelength of zeta is smaller than the curvature radius of the universe.  The leading-order bispectrum is equal to the usual one from single-field slow-roll inflation; the terms specific for open inflation arise only in the sub-leading order when the wavelength of zeta is smaller than the curvature radius.  

1309.1593
CLASH-VLT: spectroscopic confirmation of a z=6.11 quintuply lensed galaxy in the Frontier Fields Cluster RXC J2248.7-4431
Balestra et al

As the title says.

1309.1603
Gas accreetion in disk galaxies
Combes

Gas accretion is necessary to maintain SF, spiral and bar structure, and secular evolution in galaxies.  This can occur through tidal interaction, or mass accretion from cosmic filaments.  Different processes will be reviewed to drive gas towards galaxy centers and trigger starbursts and AGN.  The efficiency of these dynamical processes can be estimated through simulations and checked by observations at different redshift, across Hubble time.  Large progress has been made on galaxies at moderate and high redshifts, allowing to interpret the SFH as a function of gas content, dynamical state and galaxy evolution.

1309.1669
Unveiling new members in five nearby young moving groups
Moór, et al

Many kinematic groups of young stars (<100 Myr) were discovered in the solar neighborhood in the past 10 years.  Since the most interesting period of planet formation overlaps with the age of these groups, their well dated members are attractive targets for exoplanet searches by direct imaging.  Combined astrometric, photometric and X-ray data, and applied strict selection criteria to explore the stellar content of five nearby moving groups.  Identified more than 100 potential new candidate members in the ss Pic moving group, and in the Tucana-Horologium, Columba, Carina, and Argus associations.  In order to further assess and confirm their membership status, analyzed radial velocity data and lithium equivalent widths extracted from high-resolution spectra of 54 candidate stars.  Identified 35 new probable/possible young moving group members: 4 in the ss Pic moving group, 11 in the Columba association, 16 in the Carina association, and 4 in the Argus association.  Found serendipitously a new AB Dor moving group member as well. For 4 Columba systems Hipparcos based parallaxes have already been available and as they are consistent with the predicated kinematic parallaxes, they can be considered as secure new members.