1204.3896
The lifetime and powers of FR IIs in galaxy clusters
Antognini, Bird, Martini
* FR II: Radio galaxy class 2, meaning two lobes seen (jets may also be seen). FR I (class 1) means two jets (with plumes) seen, but no lobes.
FRIIs unlikely to contribute to cluster heating, because the energy doesn't escape the lobes efficiently. (the video was easier to understand) Jet power correlated with black hole mass, radio luminosities. Jet power not correlated with cluster richness; lifetime not correlated with any other cluster properties. Jet power approximately an order of magnitude larger than required to counteract cooling.
1204.3897
CO J=2-1 line emission in cluster galaxies at z~1: fueling star formation in dense environments
Wagg, ... Dey, Jannuzi, .. Stern, et al
IR luminous cluster galaxies at z~1, CO line emission; 2 are optically faint, dust obscured galaxies (DOGs) w/in 2Mpc of each of their cluster center. CO no detected in either. Translates to small molecular H2. Has mid-IR continuum, suggests AGN contributes to the dust heating. SF efficiencies in DOGs uncertain. A significant reservoir of molecular gas in a z~1 galaxy located away from the cluster center demonstrates that the fuel can exist to drive an increase in star-formation and AGN activity at the outskirts of high-redshift clusters.
* Na und?
1204.3901
Detection of elements at all three r-process peaks in the metal-poor star HD 170717
Roederer, Lawler
First detection of all 3 r-process peaks [which ones?!?!] in the metal-poor halo star. Elements include: As, Se (not detected previously in halo stars) and Te, Os, Ir, Pt (previously detected). Present atomic transition probabilities. Predictions are such that production of lightest r-process elements are generally decoupled from the heavier r-process elements.
* r-process: any heavy nuclei are bombarded with a large neutron flux to form highly unstable neutron rich nuclei, which very rapidly undergo beta decay to form more stable nuclei with higher atomic number and the same atomic weight. The neutron flux is astonishingly high, about 1e22 neutrons /cm^2/s. First peak at atomic mass A=130 but no actinides.
1204.3908
HST-COS observations of AGN. I. Ultraviolet composite spectra of the ionizing continuum and emission lines
Shull, Stevans, Danforth
Measure rest-fram ionizing continua and emission lines for 22 AGN, using UV COS on HST. See no Lyman edge or He I emission in the AGN composite. 22 AGNs exhibit a substantial range of FUV/EUV spectra indices and a correlation with AGN luminosity and redshift, likely due to observing below the 1000A spectral break.
1204.3910
The X-factor in Galaxies: II. the molecular hydrogen -- star formation relation
Feldmann, Gnedin, Kravtsov
Empirical relation of H2 density and SFR surface density, which holds for galaxy scale and >=kpc sized patches of ISM, but degrades at sub-kpc scale. What are the physical mechanisms that determine the scale-dependent properties of the relation? Study this relation with simulation. with peak resolution of 100 pc. Chemical network for H2, CO emission model, stochastic prescription for SF on 100pc scales. SF modeled as Poisson process in which the average SFR is directly proportional to the mass of H2. Numerical model in good agreement with Kennicutt-Schmidt and the Sigma relations Observations based on CO emission ill suited to reliably measure the slope of the latter relation at low H2 surface densities on sub-kpc scales. Sigma (H2-SFR) relation steepens at high H2 Sigma as a result of the surface density dependence of the CO/H2 conversion factor. Sub-kpc scales, most of the scatter in the relation is a consequence of discreteness effects in the SF process. In contrast, variations of the CO/H2 conversion factor are responsible for most of the scatter measured on super-kpc scales.
1204.3919
No evidence of dark matter in the solar neighborhood
Bidin, Carraro, Mendez, Smith
Surface mass density of galactic disk at the solar position, up to 4 kpc from the plane, by means of the kinematics of ~400 thick disk stars. Results match the expectations for the visible mass only, and no DM detected in the volume under analysis. Current models of DM excluded with a significance higher than 5 sigma, unless a highly prolate halo is assumed. Lack of DM at the solar position challenges current models.
1204.4074
Central kinematics of the globular cluster NGC 2808: upper limit on the mass of an intermediate-mass black hole
Lützgendorf, et al
Use high angular resolution ground-based spectrographs to measure IMBH mass kinematically, at the center of a globular cluster. Combine with HST/ACS photometric data, probe IMBH is at its center. Best fit model: no BH solution. Upper limit of M_BH<1e4 Msun (2 sigma), global M/L ratio of 2.1.
1204.4096
Image analysis for cosmology: shape measurement challenge review & results from the mapping dark matter challenge
Kitching, Rhodes, Heymans, Massey, et al
* must read this paper!
Mapping DM competition, 700 submissions in 2 months, factor of 3 improvement in shape measurement accuracy on high S/N galaxies and 10 improvement tested on constant shear blind simulations. Review WL shape measurement challenges.
1204.4114
Observational evidence of AGN feedback
Fabian
AGN feedback (which presumably is responsible for the central SMBH and host galaxy mass) evidence is difficult to obtain, but is accumulating. Radio emission common in massive elliptical galaxies; well observed directly through x-ray observations of the central galaxies of cool core clusters in the form of bubbles in the hot surrounding medium. Energy flow (roughly continuous) heats the hot IC gas and reduces radiative cooling and subsequent SF by an order of magnitude. Feedback appears to maintain a long-lived heating/cooling balance. ...
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