Friday. JC didn't suck, but I didn't get yesterday's astro-ph reading done.
Saturday. Finish up Friday's reading. Düsseldorf today!
Sunday. German Tax done: 1100 EUR back, 500 EUR to the Steuerberater (tax advisor).
1207.4182
Suzaku observations of the non-thermal supernova remnant HESS J1731-347
Bamba et al
Non-thermal x-ray emission analysis, hard and line-less. Simple absorbed power-law model, absorption column density N_H of 1-2e22 /cm2; varies by region. Compare morphology with VHE gamma-ray and radio images. Differences in efficiency of e- acceleration and emission mechanism in each region. Thermal x-ray not detected.
1207.4185
The Fermi bubbles: supersonic AGN jets with anisotropic cosmic ray diffusion
Yang, Ruszkowski, Ricker, Zweibel, Lee
Bubbles: ~50 degrees above and below the galactic center. The key characteristics of the observed gamma-ray bubbles and the spatially-correlated X-ray features in ROSAT 1.5 keV map can be successfully reproduced by a recent jet activity from the central AGN. Formation time ~ 1Myr.
The Fermi bubbles: supersonic AGN jets with anisotropic cosmic ray diffusion
Yang, Ruszkowski, Ricker, Zweibel, Lee
Bubbles: ~50 degrees above and below the galactic center. The key characteristics of the observed gamma-ray bubbles and the spatially-correlated X-ray features in ROSAT 1.5 keV map can be successfully reproduced by a recent jet activity from the central AGN. Formation time ~ 1Myr.
1207.4190
Galaxy Zoo: bulgeless galaxies with growing black holes
Simmons, ... Nichol, et al
13 AGN in massive (M*>1e10Msun) bulgeless galaxies; assume bulge is a signature of merger assembly history [Hmm...]. Compute BH masses for 2 BL objects and place lower limit on remaining sample (>1e6 Msun). Significant BH growth must be possible in absence of mergers. If the mean Eddington ratio are typical (~6%), then BH mass and stellar mass correlation are consistent for 10/13. Implies: details of stellar galaxy evolution and dynamics may not be fundamental to the co-evolution of galaxies and black holes (relation in elliptical/bulge-dominated galaxies also relevant to disk-only galaxies).
1207.4191
The role of cold gas and environment on the stellar mass - metalicity relation of nearby galaxies
Hughes et al
Observe a relationship where gas-poor galaxies are typically more metal-rich [depends on the H detection method, I think--is it detecting cold gas only? Does it detect hot H gas? This method uses HI 21 cm line.]. Removal of gas from the outskirts of spirals increases the observed average metallicity by 0.1 dex. Stellar-mass metallicity relation is nearly invariant to the environment. Internal evolutionary processes play a key role in shaping the M*-metallicity relation.
1207.4203
Low and high surface brightness galaxies at void walls
Ceccarelli et al
Compare galaxies in field and void walls: significant decrement (4x) of the relative fraction of blue, active SF LSBGs in equal mass groups at the void walls and the field. This decrement consistent with an increase of the fraction of blue, active SF HSBGs. [So more blue HSBGs at void shells compared to than in field?] Red LSBGs and HSBGs show negligible changes. Consistent with scenario where LSBGs with blue colors and strong SF activity at the void walls are fueled by gas from expanding void regions.
1207.4692
Lensing degeneracies and mass substructure
Liesenborgs, Rijcke
Generalization of mass sheet and monopole [?] degeneracy allows any number of sources to be rescaled.
1207.4321
Investigating emission line galaxy surveys with the Sloan digital sky survey telescope
Comparat, Kneib, ... Bailey, Dawson, Leauthaud, Percival, Ross, Schlegel, Schneider, .. et al
Show a selection scheme that has 75% redshift measurement efficiency.
1207.4369
Redshifts, sample purity, and BCG positions for the galaxy cluster catalog from the first 720 square degrees of the South Pole Telescope Survey
Song et al
224 galaxy cluster candidates detected with SZ for 720 sq. deg. with SPT survey: 57 clusters have z info; the photoz from red sequence determine the rest of the redshifts. Accuracy is delta(z)/(1+z) of 0.017. 158 systems have redshifts; lower limit z's for the others. z med = 0.57, z max = 1.35. 18% at z>0.8. Assume unconfirmed clusters are noise fluctuations; estimate lower limit to purity. If S/N>5, then purity > 95%. (70% for 4.5). Catalog of the red BCG positions. Radial distribution of offsets (rBCG and SPT SZ center) is similar to that seen in X-ray-selected cluster samples. Similar fraction of recent mergers.
1207.4374
The VIMOS public extragalactic redshift survey (VIPERS): spectral classification through principal component analysis
Marchetti et al
27k spectra of galaxies in 0.4<z<1.0. Template effectively condense the spectral information into two coefficients (age and SFR), will be part of VIPERS data releases.
1207.4456
Black Hole - Bulge relationship of post-starburst quasars at z \si 0.3
Hiner et al
M_BH - sigma* relation studied for local galaxies, but very few direct measurements of stellar velocity dispersions further out; study 6 "post starburst quasar systems" at z~0.3. Spectra display AGN features including broad emission lines and host galaxy Balmer absorption series (post-starburst stellar population). These queasars fall on or above the locally defined MBH-sigma* relation; consistent with other z>0.5 studies. Generally consistent with M_BH - Lbulge relation. Some of these bulges may be dynamically peculiar.
[Thu **/42]
Galaxy Zoo: bulgeless galaxies with growing black holes
Simmons, ... Nichol, et al
13 AGN in massive (M*>1e10Msun) bulgeless galaxies; assume bulge is a signature of merger assembly history [Hmm...]. Compute BH masses for 2 BL objects and place lower limit on remaining sample (>1e6 Msun). Significant BH growth must be possible in absence of mergers. If the mean Eddington ratio are typical (~6%), then BH mass and stellar mass correlation are consistent for 10/13. Implies: details of stellar galaxy evolution and dynamics may not be fundamental to the co-evolution of galaxies and black holes (relation in elliptical/bulge-dominated galaxies also relevant to disk-only galaxies).
1207.4191
The role of cold gas and environment on the stellar mass - metalicity relation of nearby galaxies
Hughes et al
Observe a relationship where gas-poor galaxies are typically more metal-rich [depends on the H detection method, I think--is it detecting cold gas only? Does it detect hot H gas? This method uses HI 21 cm line.]. Removal of gas from the outskirts of spirals increases the observed average metallicity by 0.1 dex. Stellar-mass metallicity relation is nearly invariant to the environment. Internal evolutionary processes play a key role in shaping the M*-metallicity relation.
1207.4203
Low and high surface brightness galaxies at void walls
Ceccarelli et al
Compare galaxies in field and void walls: significant decrement (4x) of the relative fraction of blue, active SF LSBGs in equal mass groups at the void walls and the field. This decrement consistent with an increase of the fraction of blue, active SF HSBGs. [So more blue HSBGs at void shells compared to than in field?] Red LSBGs and HSBGs show negligible changes. Consistent with scenario where LSBGs with blue colors and strong SF activity at the void walls are fueled by gas from expanding void regions.
1207.4692
Lensing degeneracies and mass substructure
Liesenborgs, Rijcke
Generalization of mass sheet and monopole [?] degeneracy allows any number of sources to be rescaled.
1207.4321
Investigating emission line galaxy surveys with the Sloan digital sky survey telescope
Comparat, Kneib, ... Bailey, Dawson, Leauthaud, Percival, Ross, Schlegel, Schneider, .. et al
Show a selection scheme that has 75% redshift measurement efficiency.
1207.4369
Redshifts, sample purity, and BCG positions for the galaxy cluster catalog from the first 720 square degrees of the South Pole Telescope Survey
Song et al
224 galaxy cluster candidates detected with SZ for 720 sq. deg. with SPT survey: 57 clusters have z info; the photoz from red sequence determine the rest of the redshifts. Accuracy is delta(z)/(1+z) of 0.017. 158 systems have redshifts; lower limit z's for the others. z med = 0.57, z max = 1.35. 18% at z>0.8. Assume unconfirmed clusters are noise fluctuations; estimate lower limit to purity. If S/N>5, then purity > 95%. (70% for 4.5). Catalog of the red BCG positions. Radial distribution of offsets (rBCG and SPT SZ center) is similar to that seen in X-ray-selected cluster samples. Similar fraction of recent mergers.
1207.4374
The VIMOS public extragalactic redshift survey (VIPERS): spectral classification through principal component analysis
Marchetti et al
27k spectra of galaxies in 0.4<z<1.0. Template effectively condense the spectral information into two coefficients (age and SFR), will be part of VIPERS data releases.
1207.4456
Black Hole - Bulge relationship of post-starburst quasars at z \si 0.3
Hiner et al
M_BH - sigma* relation studied for local galaxies, but very few direct measurements of stellar velocity dispersions further out; study 6 "post starburst quasar systems" at z~0.3. Spectra display AGN features including broad emission lines and host galaxy Balmer absorption series (post-starburst stellar population). These queasars fall on or above the locally defined MBH-sigma* relation; consistent with other z>0.5 studies. Generally consistent with M_BH - Lbulge relation. Some of these bulges may be dynamically peculiar.
[Thu **/42]
1207.4475
Inventorying the stellar initial mass function of early-type galaxies
Tortora, Romanowsky, Napolitano
From 4500 early-type galaxies in SPIDER project, plot delta_IMF (difference from that of MW) with sigma* (stellar velocity dispersion), which show strong correlation, independent of DM profile. Convergence to a systematic variation in the IMF such that high-sigma* early type galaxies have an excess of low-mass stars relative to spirals and low-sigma* early types. [is this a statement on the initial state, or the resultant observations of more low-mass stars in these old, massive galaxies?]
1207.4476
The nature of assembly bias - II. Halo spin
Lacerna, Padilla
In numerical simulations, higher spin haloes are more strongly clustered than lower spin haloes of equal mass. Redefinition of overdensity peak does not remove this effect due to: (1) only a few objects of low-virial mass are moved into the mass range where the spin introduces an assembly bias with this definition; (2) this formalism does not alter the mass of massive objects.
1207.4477
The effects of viewing angle on the mass distribution of exoplanets
Lopez, Jenkins
For radial-velocity techniques, a predictable low-mass decline. Single power law may not adequately describe the sample population.
1207.4478
The SEDs, host galaxies and environments of variability selected AGN in GOODS-S
Villforth, Sarajedini, Koekemoer
Variability selection reliably identifies AGN, predominantly of low luminosity. Some star contamination as well as no AGN activity objects, consistent with false positive rate. The most luminous AGNs avoid dense regions, while some low-luminosity AGN hosted by late-type galaxies are found near the centres of groups.
1207.4489
The origin and evolution of metallicity gradients: probing the mode of mass assembly at z=2
Jones, Ellis, Richard, Jullo
Imaging spectroscopy of SL z=2-2.4 galaxies to measure gas-phase metallicity. 4 galaxies with known kinematic properties. 2/4 gradients much steeper than local, 3rd one similar to local disk, 4th exhibits complex kinematics (ongoing merger, inverted gradient). On average, metallicity gradients must flatten by a factor of 2.5 between z=2.2 and present. Factor approximately the same as growth of massive galaxies; suggests inside-out growth can account for the evolution of metallicity gradients. Develop simple model of chemical evolution: find metallicity gradients and their evolution can be explained by the inward radial migration of gas together with a radial variation in the mass loading factor, governing the ratio of outflowing gas to the local star formation rate [??]. Average mass loading factors [?] of <~2 inferred from model; good agreement with direct measurements of outflowing gas in z~2 galaxies.
* inward migration and SF-based outflow causes metallicity gradients.
1207.4518
Reflection and dissipation of Alfv\'en waves in interstellar clouds
Pinto, Verdini, Galli, Velli
* Alfven wave: a type of magnetohydrodynamic wave. And Alfven wave in a plasma is a low-frequency (compared to ion cyclotron frequency) travelling oscillation of the ions and the B-field. The ion mass density provides the inertia, and the B-field tension provides the restoring force.
Supersonic nonthermal motions in molecular clouds are often interpreted as long-lived MHD waves. Affected by gas density and the ionization fraction. Aim: study propagation, reflection and dissipation of Alfven waves in molecular clouds deriving the behavior of observable quantities such as the amplitudes of velocity fluctuations and the rate of energy dissipation. MHD waves propagating in 1d inhomogeneous medium, including the dissipation due to collisions between ions and neutrals and to a NL turbulent cascade treated in a phenomenological way. ...Results: Waves incident on overdense regions with densit profiles typical of cloud cores embedded in a diffuse gas suffer enhanced reflection in the regions of the steepest density gradient, and strong dissipation in the core's interior. Significant when wavelengths are intermediate between the critical wavelength for propagation and the typical scale of density gradient. Conclusions: the results help to interpret the sharp decrease of line width observed in the environments of low-mass cloud cores in several molecular transitions.
1207.4541
Four new observational $H(z)$ data from luminous red galaxies Sloan digital sky survey data release seven
Zhang, Zhang, Yuan, Zhang, Sun
Measure Hubble parameter from 17k LRGs from SDSS DR7 (0<z<0.4). With single stellar population models (SSP), derive optimal age information of sample; From the decreasing age-redshift relation, obtain the H(z) data points at z=0.07, 0.12, 0.2, 0.28. Constrain LCDM.
1207.4543
The Atacama cosmology telescope: cross-correlation of CMB lensing and quasars
Sherwin, Das, ... Devlin, Dunkley, .. Halpern, ... Hughes, ... Hlozek, ... Marriage, Marsden, ... et al
Measure cross-correlation of ACT CMB lensing convergence maps with quasar maps made from SDSS DR8 photometric catalog (SDSS-XDQSO). 3.8 sigma detection; confirms that quasar distribution traces the mass distribution at z>1. Measure the amplitude of the linear quasar bias assuming a template for its redshift dependence; find amplitude consistent with earlier measurement of clustering. At z~1.4, measurement corresponds to b=2.5 pm 0.6. S/N ratio on CMB lensing measurements likely to improve by an order of magnitude over the next few years; demonstrate probing CMB lensing cross correlation at high-z in the future.
1207.4555
The impact of baryons on the spins and shapes of dark matter haloes
Bryan, Kay, Duffy, Schaya, Vecchia, Booth
Use sims to see how DM halo statistical properties are affected by baryonic processes associated with galaxy formation. Baryons increase the spin of the DM in the central region (<0.25 r200) by up to 50% when feedback is weak or absent [how frequently are they weak or absent? Rarely? Frequently? 50%?]; attributed to the transfer of angular momentum from baryons to the DM [how physical is it--this interaction should be purely gravitational]. At z=0 the triaxiality is positively correlated with halo mass, but these trends are weaker at z=2. Cooling of baryons acts to make the overall DM halo more spherical, but stronger feedback (from AGN) tend to reduce the impact of baryons by reducing the central halo mass concentration. Demonstrate positive correlation between halo sphericity and galaxy formation efficiency (measured using central halo baryon fraction). Effects of baryons on DM halo spin and shape are minor when the effects of cooling are mitigated, although they remain significant for the inner halo.
[Fri **/46]
