1202.4454
Loops formed by tidal tails as fossil records of a major merger
Wang, Hammer, Athanassoula, Puech, Yang, Flores
Haloes of disk galaxies can be explained by gas-rich major mergers (such as those seen in NGC 5907), according to simulation; not satellite infall (which would leave a nucleus, but often not found). 3:1 or 5:1 merger likely just as 12:1 intermediate mergers, producing red colors, presence of faint extended features (such as loops), thin extended disks.
1202.4457
An attractor for the dynamical state of the ICM
Juncher, Hansen, Maccio
The temperature-density relation in galaxy clusters (according to high-res sims) show that it is a "real attractor", showing that a wide range of equilibrated structures all move towards the attractor when perturbed and subsequently allowed to relax. A relaxed system therefore allows mass estimates directly from X-ray profiles.
1202.4459
The hubble constant and new discoveries in cosmology
Suyu, Treu, Blandford, Freedman, Hilbert, Blake, ... Courbin, Dunkley, ... Marshall, ... Reid, et al
Workshop summary: (1) better measurements of H0 provide critical independent constraints on dark energy, spatial curvature of the universe, neutrino physics, and validity of GR, (2) H0 measurements to 1% in both precision and accuracy is within reach for several methods, and (3) multiple paths to independent determinations of H0 are needed to access and control systematics.
1202.4464
The stellar halos of massive elliptical galaxies
Greene, Murphy, Comperford, Gebhardt, Adams
8 Ell galaxies, chemical signatures of massive elliptical galaxy assembly from an integral-field spectrograph. Study radial dependence in the EWs of key metal absorption lines. Metallicity gradient found; stellar haloes have low metallicities and high alpha-abundance ratios, just like the MW. Observations support picture in which the outer parts of massive elliptical galaxies are built by the accretion of much smaller systems whose SFH was truncated at early times.
1202.4470
RX J1548.9+0851, a fossil cluster?
Eigenthaler, Zeilinger
Fossil galaxy groups: spatially extended x-ray sources above 1e42 erg/s bolometric luminosity, and a central elliptical galaxy dominating the optical (2nd brightest at least 2 mag fainter in the R band). Only small objects studied. Extend study to this system at z=0.072. Get total of 54 spectra of members within 1 Mpc. Find mass at 2.5e14 Msun, confirming fossils to be massive.
1202.4474
The resolved structure and dynamics of an isolated dwarf galaxy: a VLT and Keck spectroscopic survey of WLM
Leaman, Venn, Brooks, Battaglia, Cole, Ibata, Irwin, McConnachie, Menel, Tolstoy
Observations of 180 red giant branch stars in a dwarf irregular WLM suggests: extended vertical structure of its stellar and gaseous components and increase in stellar velocity dispersion with age are due to internal feedback, rather than tidally driven evolution.
1202.4481
Constraints on the formation of the galactic bulge from Na, Al, and Heavy element abundances in Plaut's field
Johnson, Rich, Kobayashi, Fulbright
At least a majority of bulge stars formed rapidly (<1 Gyr) and before s-process could become a significant pollution source. Inner disk clump stars exhibit abundance patterns more similar to disk stars. Inner and outer bulge formed on similar time scales. Halo may have had a more significant impact on the outer bulge initial composition than the inner bulge.
1202.4489
The mid-IR environments of high-z radio galaxies
Galametz, Stern,... et al
Find radio galaxies lie preferentially in medium to dense regions (dense, as defined by Spitzer IR-detected galaxies).
1202.4490
Overdensities of 24um sources in the vicinities of high-z radio galaxies
Mayo, Vernet, Breuck, Galametz, Seymour, Stern
HzRGs are likely to lie in protoclusters of active and SF galaxies at high-z. At 24um, source density does not depend on radio luminosity.
1202.4501
Testing gravity with the stacked phase space around galaxy clusters
Lam, Nishimichi, Schidt, Takada
The average velocity field of DM in galaxy clusters is uniquely determined by the mass profile. Measure the latter from WL. Stack redshift of surrounding galaxies from a spectroscopic sample; combine with lensing. Direct test on gravity scales of 1-30 Mpc. Use N-body sims, show that this method can improve upon current constraints by several orders of magnitude when applied to upcoming imaging and z surveys.
1202.4516
ATLBS extended source sample: the evolution in radio source morphology with flux density
Saripalli, Subrahmanyan, THorat, Ekers, Hunstead, Johnston, Sadler
119 High-z radio sources; large (>0.7Mpc) radio sources not uncommon at z>1. Equal ratio of FR-I and FR-II types. Significant asymmetry in lobe extent appears to be common in FR-I sources compare to FR-II sources. 28 restarted radio galaxies. Dying and restarting indicative of model where radio sources undergo episodic activity.
1202.4536
Generation of strong magnetic fields via the small-scale dynamo during the formation of the first stars
Banerjee, Sur, Federrath, Schleicher, Klessen
High-res computer sims on turbulent amplification of weak B-field seeds: such fields will exponentially be amplified also during the gravitational collapse, similar to during primordial star formation. Exponential B field amplification driven by the turbulent small-scale dynamo (barely resolved in simulations). The Jeans length must be resolved by at least 30 grid cells to capture the dynamo activity.
1202.4674
The dominant role of mergers in the size evolution of massive early-type galaxies since z~1
Lopez-Sanjuan, Le Febre, Ilbert, ... Kneib, Lilly, ... Scoville, Taniguchi, ... et al
Measure merger fraction and rate of massive early-type galaxies (M*>1e11 Msun) in the COSMOS field. Study redshift and morphology dependence. Merger fraction and rate evolves as a power law (1+z)^n, with major mergers at n_MM=1.4, and minor mergers showing little evolution, n_mm~0. Split by morphology, minor merger fraction for early types is higher by a factor of 3 than that for spirals; both are nearly constant with redshift. Fraction of major mergers for massive spirals evolve faster than for early types (n_MM^spiral ~ 4, where n_MM^ellptical=1.8). Merging is the main contributor to the size evolution of massive ETGs at z<1, accounting for 50-80% of the evolution in the last 8 Gyr. Nearly half of the evolution due to mergers is related to minor events.
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