Day 209

Wednesday.  Did an OK Journal Club yesterday.  Annoyed Aaron further.  Now I am 5 days behind.


1202.4755
Evidence for top-heavy stellar initial mass functions with increasing density and decreasing metallicity
Marks, Kroupa, Dabringhausen, Pawlowski


From observation of globular cluster masses, radii, metallcity, and PDMF, find: IMF is required to become more top-heavy the lower the cluster metallicity and the larger the pre-GC cloud-core density are; in agreement with theoretical expectation.  GCs and UCDs might have formed along te same channel, or UCDs formed via mergers of GCs.  Find fundamental plane which describes the variation of the IMF with density and metallicity of the pre-GC cloud-cores simultaneously.  Major implications to evolution of galaxies, and chemical enrichment.


1202.4758
Spatial variation in the fine-structure constant -- new results from VLT/UVES
King, Webb, Murphy, Flambaum, Carswell, Bainbridge, Wilczynska, Koch


From 154 (VLT) and 141 (Keck) quasar absorbers:  VLT shows alpha increases with increasing cosmological distance from Earth.  Keck show some evidence fro smaller alpha in the distant absorption clouds.  Combine samples: apparent variation of alpha across the sky emerges by an angular dipole model at R=17.3 hr = 259 deg, dec = -61 deg, with amplitude of 0.97e-5 at 4 sigma.  Data consistent with cuts, VLT vs. Keck.  Dipole effect does not originate from a small subset of the absorbers or spectra.  


1202.4761
Relativistic resonant relations between massive BH binary and extreme mass ratio inspiral
Seto


MBHB can capture a small third body, forming a triple system; analyze evolution of the triple initially with small eccentricities.  Find: a new resonant relation can arise, where GR effects crucial.  Relativistic resonances can significantly change the orbit of the inner small body.


1202.4767
Evolution of group galaxies from the first red-sequence cluster (RCS) survey
Li, Yee, Hsieh, Gladders


* Butcher-Oemler effect: distant clusters contain more blue galaxies than nearby ones.


Study red fraction in RCS1 clusters, find BO effect in groups, from 0.15<z<0.52.  Luminous red sequence galaxies are already in place by z~0.5, formation epoch of z>2.  Study evolution of f_red as a function of (1) Stellar mass, (2) total group stellar mass, (3) normalized group-centric radius, and (4) local galaxy density.  M* (1) strongest effect on f_red, then environment (2,3,4).  Once massive (M>1e11 Msun), little dependence seen on the parameters; dependence mostly seen in M*<1e10.6 Msun galaxies.  Observe an apparent 'group downsizing' effect.  At fixed size (3), significant dependence on f_red on local density (4), and f_red gradients seen for fixed (4); indicates galaxy group environment has a residual effect over that of local galaxy density (or vice versa), both params need to be considered.  Red galaxy state are caused both by local galaxy density (harassment and mergers) and accretion onto larger group halo (ram pressure and strangulation).


1202.4770
The physics of the fundamental metallicity relation
Dayal, Ferrara, Dunlop


* FMR: Metallicity, mass, SFR relation in a plane.


Show: physics of the FMR summarised as follows: Massive galaxies with M*>1e11 Msun has low metallicity gas inflow, and retains high metallicity gas outflow, leading to a constant value of the gas metallicity with SFM.  Less massive galaxies have smaller SFR, produce less heavy elements, more efficiently ejected due to shallower potential: as a result, the gas metallicity decreases with SFR for a given stellar mass; the outflow efficiency determines the slope and the knee of the metallicity-SFR relation.  Model successfully matched to results from numerical simulations including metal enrichment and feedback at higher z.


1202.4783
The contribution of TP-AGB and RHeB stars to the Near-IR luminosity of local galaxies: Implications for stellar mass measurements of high redshift galaxies
Melbourne, et al


HST imaging of resolved stellar populations in 23 nearby galaxies show that TP-AGB starns and red helium burning (RHeB) stars contribute to 1.6 um NIR luminosity by up to 20% each.  The NIR mass-to-light ratio should be therefore be expected to vary significantly due to fluctuations in the star formation rate over timescales from 25 Myr to several Gyr.  Compare observational results to derived SFH and SPS models.  The SPS models generally reproduce the expected numbers of TP-AGB stars, but give larger discrepancy in the flux contribution, overpredicting by factor of 2.3; offset driven by the modest numbers of TP-AGB stars at young (<300 Myrs) ages.  Best-fit SPS models tend to under-predict the numbers and fluxes of HReB stars by a factor of 2.  These two discrepancies result in NIR M/L largely unchanged for a rapid SFR, but NIR-to-optical flux ratio of galaxies could be significantly smaller than AGB-rich models would predict.


1202.4790
The H I environment of counter-rotating gas hosts: gas accretion from cold gas blobs
Chung, Bureau, van Gorkom, Koribalski


H I gas that is counter-rotating wrt the galaxy is most likely due to the gas flowing in from each of the neighboring galaxies, for the 3 galaxies studied.


1202.4804
Characterizing the nature of fossil groups with XMM
La Barbera, Paolillo, De Fiippis, de Carvalho


6 Fossil group candidates from SDSS and RASS studied with X-ray follow up, 4 confirmed; 2 have x-ray bright AGN or blending of distinct x-ray sources.  Find r-band magnitude gap between seed elliptical and the second-rank galaxy; but gap value can change/wrong if using SDSS magnitudes.  Bright ellipticals in FGs do not represent a distinct population of galaxies (seed FGs and non-fossil ellipticals have similar properties).  FGs don't seem to necessarily form a population of true fossils.


1202.4870
Evolutionary synthesis models as a tool and guild towards the first galaxies
Schaerer


Summarize the principles and fundamental ingredients of evolutionary synthesis models: stellar evolution, stellar atmospheres, the IMF, SFH, nebular emission, and attenuation from ISM and IGM.  Importance for predictions of metal-poor and Pop III dominated galaxies.  Predicted observables: rest-frame UV-to-optical domain with continuum emission from stars and the ionized ISM, plus emission lines from H, He, and metals.  Based on these predictions, summarize the main observational signatures (colors, emission lines, etc) which can be used to distinguish "normal" stellar populations from very metal-poor objects or even Pop III.  


1202.4890
Non-Gaussian isocurvature perturbations in dark radiation
Kawakami, Kawasaki, Miyamoto, Nakayama, Sekiguchi


Study non-G properties of the isocurvature perturbations in the dark radiation (active neutrinos and possible extra light species).  First derive bispectra of primordial perturbations (mixture of curvature and dark radiation isocurvature perturbations).  Also discuss CMB bispectra produced in this model, and their constraints.  Some concrete particle physics models give neutrino density (or light species) isocurvature perturbations.


1202.4927
Multimodality in galaxy clusters from SDSS DR8: substructure and velocity distribution
Einasto, et al


Study galaxy clusters with at least 50 member galaxies from SDSS DR8.  >80% have substructure, median value of peculiar velocities of the main galaxies in clusters is 206 km/s (41% of the rms velocity); the velocities of galaxies in more than 20% of the clusters show significant non-Gausisanity.  Richer, larger and more luminous clusters have larger amount of substructure and larger peculiar velocities of the main galaxies.  PCA of both substructure indicators and physical parameters of clusters show that galaxy clusters are complicated objects (cannot be explained by a small number of parameters).  The presence of substructure, the non-G velocity distributions, as well as the large peculiar velocities of the main galaxies, shows that most of the clusters in our sample are dynamically young.


1202.4936
Rip/singularity free cosmology models with bulk viscosity
Meng, Ma


Universe with a non-perfect fluid with bulk viscosity to interpret the observed cosmic accelerating expansion.  Fits observations.


1202.5004
Intermediate old star clusters in a young starburst: the case of NGC 5253
Harbeck, Gallagher, Crnojevic


Found high global SFR at 1-2 Gyr-aged massive star clusters.  Current star burst is just one episode in an very active galaxy.

Day 208

Monday.  4 days behind in the reading...  Aaron told me not to show up without notifying him.  Bleah.  Sorry!

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.

Day 207

Sunday.  Went running down to the park today.  Had Korean Bibimbap for dinner last night; gave a meal to Aaron today.  He's down with the flu.  I'm 3.5 days behind on my reading.

1202.4275

The effect of feedback on the emission properties of the WHIM

Roncarelli, Cappelluti, Borgani, Branchini, Moscardini

Half of all the unresolved X-ray BG in the 1-2 keV band must be emission from faint groups and WHIM.  (Presently, 30-40% of baryons in the local universe still undetected; must be in the form of WHIM in LSS filaments at temperatures of 1e5-1e7 K.)  Characterize the properties of X-ray emission of WHIM from (1) Galactic winds, (2) BH feedback and (3) star formation.  Use simulation to calculate x-ray emission in the 0.3-10 keV range.  O VII and O VIII lines increase by a factor of 3 due to GWs.  GWs increase x-ray by factor of 2 in both clusters and WHIM.

1202.4277

A density independent formation of SPH

Saitoh, Makino

SPH assumes local density distribution differentiable; problems occur when there is contact discontinuity--unphysical repulsive force appears, resulting in the effective surface tension, suppressing KH and RT instabilities.  Present new formulation of SPH that does not require differentiability of density.  Seems to do well in instability tests.

1202.4321

A study of optical observing techniques for extra-galactic SNe remnants: Case of NGC 300

Millar, White, Filipovic

Using [S II]/Halpha > 0.4 in optical SNR surveys ad identifying feature of extra-galactic SNRs is a questionable technique, and very high-resolution images may be needed to confirm a valid identification of some egSNRs.

1202.4328

Ultra deep sub-kpc view of nearby massive compact galaxies

Trujillo, Carrasco, Ferre-Mateu

Study 4 nearby ultra-compact galaxies (M~1e11 Msun, R<1.5 kpc, z~0.15).  These galaxies are typically found at high-z; they also share similar characteristics in size, mass, velocity dispersion, but also the shape profiles and age of stellar populations.

1202.4433 (1112.5045)

An anomaly in the angular distribution of quasar magnitudes: evidence for a bubble universe with a mass 1e21 Msun

Longo

Quasar magnitude anisotropy toward (alpha, delta)~(195 deg, 0 deg) for all wavelengths, can be explained by a massive bubble lens with 1e21 Msun with lens radius ~350 Mpc, with the lens subtending an angle 15 deg on the sky.  Anomaly in the distribution of LRG, CMB and bulk flow all appear roughly in the same direction.

1202.4450

The XMM Cluster survey: the stellar mass assembly of fossil galaxies

Harrison, ... Liddle, et al

Fossile (cluster/group) systems formed early and in the highest density regions of the universe; fossil galaxies represent the end products of galaxy mergers in groups and clusters.  Gap between BCG and 4th brightest cluster is positively correlated to: total luminosity / fraction luminosity of the brightest galaxy.  The fossil galaxies (BCG in fossil systems) have stellar pops and SFH similar to normal brightest cluster galaxies; but the stellar masses of fossil galaxies are larger compared to normal BCG.  Fossil systems have most (as high as 85%) of their optical luminosity within 1/2 r200, where for other systems it could be a low as 10%.

Day 206

Tuesday.  Last night of the observation run.  I sense that he is depressed.  Or maybe I'm crazy.


Wednesday.  I was crazy.  He had a good time at the Karnaval; good weather in Bonn.  


Thursday.  On the train from Frankfurt.  Made it to Journal Club.  Gave wine to Aaron.  That's it.

1202.3438

Plain fundamentals of fundamental planes: analytics and algorithms

Sheth, Bernardi

Provide explicit expressions for 2 variables (and confidence limits) in a 3-variable planar relation in terms of the covariances between the log of the 3 variables.  Use for Fundamental Plane (R, Sigma, I), color-magnitude-Sigma relation, L-Sigma-Mbh relation, or X-ray lum- SZ decrement, and optical richness of cluster.  Provide code.  Show how analysis generalizes to correlations between more than 3 variables.  Show how to account for correlated errors and selection effects; quantify the difference between the direct, inverse and orthogonal fit coefficients.  Why is Sigma and I only weakly correlated in ellipticals?  A fundamental question.  If lack of correlation existed in the past, then differential luminosity evolution must have been accompanied by structural evolution [didn't quite follow the logic here].  A model in which the luminosities of low-L galaxies evolve more rapidly than do those of higher-L galaxies is able to produce the observed decrease in "a" (/2 at z~1) while having "b" decrease by only about 20 percent.

1202.3441

Forming early-type galaxies in LCDM simulations - I. Assembly histories

Johansson, Naab, Ostriker

Hi-res LCDM cosmo simulations with primordial radiative cooling, photoionization, star formation, SNII feedback (exclude SNe driven winds and AGN feedback).  Simulated galaxy assemble in two phases: initial growth dominated by compact in situ star formation fueled by cold, low entropy gas streams, whereas the late growth is dominated by accretion of old stars formed in subunits outside the main galaxy.  The two-phase formation mechanism naturally explains the observed downsizing [what is this?], bimodality and size growth of the galaxy population.  Gravitational feedback strongly suppresses late SF win massive galaxies.  Additional heating sources probably in the form of AGN and SNI feedback are also required to prevent late gas inflows and associated residual SF in more massive galaxies.  Accretion of stellar material (dry minor mergers) is also responsible for the observed size growth of early-type galaxies.  Find: DM fraction within the stellar half-mass radii continuously increase towards lower redshift from f_DM~0.05 at z~3 to f_DM~0.1-0.3 at z=0.  In addition, the logarithmic slope of the total density profile is nearly isothermal at the present-day, good agreement with recent lensing observations.  Simulations predict almost constant slopes until z=1, and then steeper slopes of gamma~3 at higher z.

1202.3522

Constraints on the origin of the ultra-high energy cosmic rays using cosmic diffuse neutrino flux limits: an analytical approach

Yoshida, Ishihara

Convert the upper-limits on the neutrino fluxes into the constraints on the CR sources.

1202.3554

Reconstruction of total solar irradiance 1974-2009

Ball, et al

Strong evidence that changes in photospheric magnetic flux alone are responsible for almost all solar irradiance variations over the last three solar cycles.

1202.3577

The intergalactic medium thermal history at z=1.7 to 3.2 from the Ly-a forest: a comparison of measurements using wavelets and the flux distribution

Garzilli, Bolton, Kim, Leach, Viel

Investigate IGM in 1.7<z<3.2 by studying the small-scale fluctuations in the Ly-a forest transmitted flux.  Compare data to synthetic spectra drawn from a suite of hydro sims in which the IGM thermal state and cosmological parameters are varied.  IGM thermal state in good agreement with other independent measurements.  PDF and wavelet analysis agree, but flux PDF  favor an isothermal or inverted IGM temperature-density relation.  Joint analysis with PDF: results consistent with previous observations that indicate there may be additional sources of heating win the IGM at z<4.

1202.3665

emcee: The MCMC Hammer

Foreman-Mackey Hogg, Lang, Goodman

A stable, well tested Python implementation of the affine-invariant ensemble sampler for MCMC. Code is open source.  Algorithm of emcee has advantages over traditional MCMC sampling; has excellent performance as measured by the autoorrelation time.  One major advantage: requires hand-tuning of only 1 or 2 parameters compared to N2 for a traditional algorithm in an N-dimensional parameter space.  Describe the algorithm and details of the implementation and API.  Allows parallel processing.  Available at http://danfm.ca/emcee.

1202.3783

Is quasar variability a damped random walk?

Zu, Kochanek, Kozlowski, Udalski

Still uncertain whether the DRW model provides an adequate description of quasar variability across all time scales.  Use OGLE quasar light curves to check 4 modification to the DRW model.  Over long (observed) timescales, excellent agreement.  Over shorter (<few months) scales, some evidence of an existence of cutoff time scale below which the correlation is stronger than the DRW model.  On >few year time scale, agrees well with DRW, but not constrained well.

1202.3787

The XMM Cluster Survey: the interplay between the brightest cluster galaxy and the ICM via AGN feedback

Stott, ...Kay, ... Liddle, ... Schaye, et al

Use 123 Xray clusters and groups and investigate interplay between BCG, its BH, and the ICM.  For groups and clusters with a BCG likely to host significant AGN feedback, gas cooling dominates in those with Tx>2keV, while AGN feedback dominates below.  Evidence for a combination of central gas cooling and powerful, well fueled AGN causes the departure of the ICM from pure gravitational heating , with the steepened relation crossing self-similarity at T_X=2keV.  Demonstrates that the most massive BHs appear to know more about their host cluster than they do about their host galaxy (regardless of their BH mass, BCGs are more likely to host radio-loud AGN if the yard in a massive T_X>2keV cluster and again co-located with an effective fuel supply of dense, cooling gas).

1202.3791

On the average density profile of DM haloes in the inner regions of massive early-type galaxies

Grillo

Take average of 39 Ell galaxies at z<0.3 to determine the slope of the average DM density profile in the innermost regions, from SL data.  Keep SL and SPS modeling as simple as possible.  The DM projected density profile log slope is -1 (isothermal) or -0.7 (shallower than isothermal) if a Chabrier, or Salpeter-like stellar IMF is adopted.  These results provide positive evidence of the influence of the baryonic component on the contraction of the galaxy DM haloes, compared to DM only simulations.  New way to test models of structure formation and evolution within the standard LCDM cosmo scenario.

1202.3832

Cosmicflows-2: SNIa calibration and H0

Courtois, Tully

Merging of distance measures: Cepheid, "tip of the red giant branch" (TRGB), surface brightness fluctuations (SBF), luminosity-linewidth (TF), fundamental plane (FP), and SNIa.  Hubble constant is H0=75 km/s/Mpc.

1202.3852

THe SL2S galaxy-scale gravitational lens sample.  I:  The alignment of mass and light in massive early-type galaxies at z=0.2-0.9

Gavazzi, Treu, Marshall, Brault, Ruff

Relative alignment of mass and light in a sample of 16 massive Ell galaxies at 0.2<z<0.9 that act as SL.  Infer that there is a substantial amount of external shear ~0.12, arising most likely from the environment of the lenses.  Combine these measurements to study the evolution of the stellar and DM content of Ell galaxies a function of cosmic time.

1202.3998

The shift of the BAO scale: a simple physical picture

Sherwin, Zaldarriaga

BAO scales shift to smaller values predicted by linear theory.  This is because BAO measurement is more sensitive to regions with long wavelength over densities than under densities.  In over dense regions, the BAO scale shrinks because such regions locally behave as positively curved closed universes.  Provide approximate analytic expressions for the nonlinear shift; shifts are different in real and Fourier space due to a change of the shape of the BAO feature.  Reconstruction should entirely reverse the shift.  Shouldn't be a problem for next-generation BAO measurements.

1202.4039
Fermi-AT Observations of the Diffuse Gamma-ray emission: Implications for CR and ISM
The Fermi-LAT collaboration


Gamma-ray sky (>100 MeV): dominated by the diffuse emissions from interactions of CRs with the interstellar gas and radiation fields of MW; observations study CR origin and propagation, and the ISM.  Compare models of diffuse gamma-ray emission using GALPROP code.  Astrophysical input: distribution of CR sources, size of CR confinement volume (halo), distribution of ISM gas.  Fit for the ratio of CO-line intensity to H2 column density, the Xco-factor [?], the flux and spectra from the point sources, and the intensity and spectrum of the isotropic BG including residual CRs that are misclassified as gamma-rays.  Models compared on the basis of their maximum likelihood ratios, as well as spectra, longitude, and latitude profiles.  Provide residual maps for the data.  Data consistent with models at high and intermediate latitude, but under-predict the data in the inner galaxy for high energies (>few GeV).  Possible explanation: contribution by undetected point source populations; spectral variations of CRs throughout the galaxy.


1202.4049
Brightness and fluctuation of the mid-IR sky from AKARI observations towards the North Ecliptic Pole
Pyo, Matsumoto, Jeong, Matsuura


AKARI NEP monitoring from 2.4 to 24 um (6 mid-IR bands).  Seasonal variation of the sky brightness show NEP is not affected by small-scale features of the interplanetary dust cloud. Power spectrum analysis: photon noise, shot noise of faint sources, and Galactic cirrus.  Few arcmin scale at short mid-IR: diffuse Galactic light of interstellar dust cirrus.  At mid IR: photon noise dominant (few arc seconds to few arcmins).  Residual fluctuation at 200" scale is 0.05% of the brightness at 24 um, or 0.02% at 18 um.  Residual is the zodiacal light at NEP.


1202.4056
Extending the M_bh-sigma diagram with dense nuclear star clusters
Graham


~68 galaxies + 29 dwarf galaxy with M_nc (nuclear cluster mass) with M_bh, construct (M_bh+M_nc)-sigma diagram.  For major dry mergers, M_bh/L ratio preserved.  L~sigma^5 for luminous galaxies.  Fainter Ell galaxies: L~sigma^2; some tension with other reports which was interpreted in terms of a regulating feedbac mechanism from stellar winds.


1202.4060
Dark energy and the fate of the universe
Li, Wang, Huang, Zhang, Li


The universe can still exist at least 16.7 Gyr before it ends in a big rip.


1202.4138
Gaia: a window to large scale flows
Nusser, Branchini, Davis


2D transverse peculiar velocities of distant galaxies (cz~2e4 km/s) can be obtained from Gaia's measurements of proper motions.  Essentially free of selection biases, is also free from homogeneous and inhomogeneous Malmquist biases.  Provides additional information to traditional probes which yield LoS peculiar velocities.


1202.4164
Environmental effects on the metal enrichment of low mass galaxies in nearby clusters
Petropoulou, Vilchez, Iglesias-Paramo


Study the chemical history of low-mass SF galaxies in local clusters Coma and 3 Abell clusters. Search for imprint of the environment on the chemical evolution of these galaxies.  Galaxy chemical evolution is linked to the SFH, as well as to the gas interchange with the environment, and low-mass galaxies are well known to be vulnerable systems to environmental processes affecting both these parameters.  Use SDSS DR8.  Sensitivity of mass-metallicity to cluster environment depends on both galaxy mass and host cluster mass.  Low-mass SF galaxies in high-mass clusters are severely affected by ram-pressure stripping.  Metal content enhancement that is mass-dependent in low-mass galaxies in dense environments plausible according to hydrosims.  Enhanced metal enrichment could be produced by the combination of effects such as wind reaccretion, pressure confinement by ICM, and the truncation of gas infall, as a result of ram-pressure stripping.  Properties of ICM should play an important role in the chemical evolution of low-mass galaxies in clusters.


1202.4242
F-GAMMA: on the phenomenological classification of continuum radio spectra variability patterns of Fermi blazars
Angelakis et al


78 sources studied; variability can be classified in 5 types, attributed to tow classes of variability mechanisms.  First 4 types: dominated by spectral evolution with two-component system of (1) a steep quiescent spectral component from a large scale jet, and (2) time evolving flare component following the shock-in-jet evolutionary path.  The 5th type is characterized by an achromatic change of the broad band spectrum, which can be attributed to a different mechanism, likely involving differential Doppler boosting chased by geometrical effects.  Present the classification, the assumed physical scenario, and the results of calculations for spectral evolution of flares.


* I'd like to read this one...


1202.4275
The effect of feedback on the emission properties of the warm-hot intergalactic medium
Roncarelli, Capelluti, Borgani, Branchini, Moscardini


30-40% of baryons in the local universe is still undetected.  This gas should reside in filaments filling the LSS in the form of WHIM, at 1e5 - 1e7 K, thus emitting in the soft X-ray energies via free-free interaction and line emission from heavy elements.  Characterize the properties of the X-ray emission of the WHIM, and the LSS in general, focusing on focusing on the influence of different physical mechanisms, namely galactic winds (GWs), BH feedback and SF, and providing estimates of possible observational constraints.  Use a set of cosmological hydrodynamical simulations that include a self-consistent treatment of SF and chemical enrichment of IGM that allow following of evolution of different metal species.  Simulate light-cones to predict emission in the 0.3-10keV energy range.  Obtain GWs increase by a factor of 2 the emission of both galaxy clusters and WHIM.   ...

Day 205

Monday, although I haven't slept since Sunday.


1202.3435
Detection of Ks-band Thermal emission from WASP-3b
Zhao, Milburn, Barman, Hinkley, Swain, Wright, Monnier


Exoplanet secondary eclipse detected, places the orbit to be circular.  Provides insight into the tidal circularization process of the star-planet system.


1202.3436
A large, multi-epoch H-alpha survey at z=2.23, 1.47, 0.84 & 0.40: the 11 Gyr evolution of SF galaxies from HiZELS
Sorbal, Smail, Best, Geach, Matsuda, Stott, Cirasuolo, Kurk


Ha used to trace SF activity over 0.4<z<2.23.  A total of 1742, 637, 515 and 556 Ha emitters are homogeneously selected at z=0.40, 0.84, 1.47, and 2.23, respectively, and used to determine the Ha luminosity function and its evolution.  The faint end slope show no evolution.  L* evolves significantly.  Ha evolution agrees well with other tracers of SF (FIR, UV): jointly pointing to a strong luminosity increase from z~0 to 2.2.  Derive Ha SFH of the universe.  Both the shape and normalization of the Ha star formation history are consistent with the measurements of the stellar mass density growth, confirming that Ha analysis traces the bulk of the formation of stars in the universe up to z~2.2.  The SF activity over the last ~11 Gyrs is responsible for producing ~95% of the total stellar mass density observed locally today.

Day 204

Sunday.  I have to catch up with astro-ph, or I'll be 4 days behind soon!  Good observations last night.  I hope it lasts through our run!


1202.3022
Reheating constraints in inflationary magnetogenesis
Demozzi, Ringeval


Show that requiring large scale magnetic fields to remain subdominant after inflation gives non-trivial constraints on both the reheating equation of state parameter and the reheating energy scale.  (Inflation is a prime candidate to explain the current existence of cosmological magnetic fields.)  B-field of order 5e-15 Gauss today. ...


1202.3032
Forecast constraints on cosmic string parameters from gravitational wave direct detection experiments
Kuroyanagi, Miyamono. Sekiguchi, Takahashi, Silk


Cosmic string can generate GWs.  Study both burst and stochastic GWs from cosmic string, which provide different information about cosmic strings, can break degeneracies in the string parameters.


1202.3039
All-particle CR energy spectrum measured with 26 IceTop stations
IceCube Collaboration


Energy spectrum from 1 to 100 PeV (1e15 eV) for 3 different zenith angle (0 to 46 deg).  The CR in this energy range is expected to be isotropic [i.e., not affected by the weak B-fields present around Earth, MW, and others].


1202.3073
Formaldehyde and methanol deuteraton in protostars: fossils from a past fast high density pre-collapse phase
Taquet, Ceccarelli, Kahane


Observation of abundant doubly and triply deuterated forms of formaldehyde and methanol: both species are thought to be formed on interstellar grains during the low temperature and dense pre-collapse phase by H and D atom additions on the iced CO.  Use gas-grain model GRAINOBLE to study deuteration of these species.  Comparison with observation shows: (1) the observed high deuteration is obtained during the last phase of the pre-collapse stage, when density reaches 5e6 cm-3, a fast phase only lasting several thousand years.  (2) D and H abstraction and substitution reactions are crucial in making up the observed deuteration ratios.  


1202.3078
The M Dwarf problem in the Galaxy
Woolf, West


M dwarf problem: the number of M dwarfs at [Fe/H]~-0.5 is less than 1% the number at [Fe/H] = 0, where a simple model of Galactic chemical evolution predicts a more gradual drop in star numbers with decreasing metallicity.


1202.3107
MASSIV: Mass assembly survey with SINFONI in VVDS. IV. Fundamental relations of star-forming galaxies at 1<z<1.6
Vergani, et al


Use 45 (SF galaxies) at 1<z<1.6, measure dynamics, galaxy size, stellar mass.  Obtain baryonic TF relation.  Obtain marginal evolution in the size-stllar mass and size-velocity relations, with disks being evenly smaller with cosmic time at fixed stellar mass or velocity, and less massive for a given velocity with respect to the local universe.  Large scatter in TF relation, probably intrinsic.  Results point towards a mild, net evolution of these relations, comparable to what is predicted by cosmological simulations of disc formation.  Lack of an influential transformation of the fundamental relations of SF galaxies for at least 8 Gyr and a dark halo strongly coupled with galactic spectrophotometric properties.


1202.3137
The 60-month all-sky BAT survey of AGN and the anisotropy of nearby AGN
Ajello, Alexander, Greiner, Madejski, Gehrels, Burlon


720 sources with Swift/BAT, 428 associated with (mostly nearby) AGN (>10keV surveys best resource to provide an unbiased census of AGN population).  Sample has negligible incompleteness and ~2x larger statistics of other similar AGN data sets.  Data contains 15 Compton-thick AGN (a 5% sample of AGN) + possibly 3 more.  LogN-LogS of AGN established to 10% precision, important for cosmic x-ray BG contribution estimation.  Concentrations of AGN coincide spatially with the super-massive clutsers in the local (<85 Mpc) universe.  


1202.3141
Supermassive BH ancenstors
Peetri, Ferrara, Salvaterra


Study model in which SMBH can grow by gas accretion on heavy seeds, and mergers of both heavy (1e5 Msun) and light (1e2 Msun) seeds.  Former: H2 free haloes, latter: standard H2 based star formation processes.  H2 free conditions: expose halos to a strong UV BG produced by accreting BHs and stars, thus establishing a self-regulated growth regime; a condition that can be met at z~18.  Key parameter allowing formation of SMBH by z=6-7 is the fraction of halos that can form heavy seeds: SMBH as large as 2e10 Msun can be obtained when f_heavy approaches unity (minimum required: f_heavy>1e-3).  Model forms bulge-BH mass relation which is steeper than local, implying that SMBHs formed before their bulge was in place.  Formation of heavy seeds is crucial to achieve a fast growth of the SMBH by merger events in the early phases of its evolution: z>7.  The UV photon production is largely dominated by stars in galaxies; BH accretion radiation is subdominant.  Find that the final mass of light BHs and of the SMBH in the quasar is roughly equal by z=6; by the same time, only 20% of the initial baryon content has been converted into stars.  The SMBH growth is dominated at all epochs z>7.2 by mergers, at later times accretion becomes by far the most important growth channel.  

1202.3143

Exploring galaxy formation models and cosmologies with galaxy clustering

Kang, Li, Lin, Elahi

Using N-body simulations and galaxy formation models, study the stellar mass correlation and the 2pt auto-correlation.  Use WMAP1, 3, 7 params (mostly differ by sigma8).  Stellar mass determined from SAM or empirical abundance matching.  Compare with SDSS DR7 at z=0, or DEEP2 at z=1.  Find: SAM galaxy clustering too high at small scales, mostly due to satellites.  Abundance matching predicts good agreement for high sigma8 cosmologies.  Galaxy clustering is strongly affected by models for galaxy formation, thus can be used to constrain baryonic physics.  Weak dependence of galaxy clustering on cosmological parameters.

1202.3191

Cosmicflows-2: I-band luminosity - HI linewidth calibration

Tully, Courtois

Derive a measure of rotation from a new characterization of the width of a neutral H line profile.  [are they talking about disk galaxies?  or dispersion velocities?]  Determine H0=75 km/s/Mpc [errors?].  

1202.3202

SNe-driven outflows and chemical evolution of dwarf spheroidal galaxies

Quian, Wasserburg

Present a general phenomenological model for the metallicity distribution (MD) in terms of [Fe/H] for dwarf spheroidal galaxies (dSphs).  These galaxies appear to have stopped accreting gas from the IGM and are fossilized systems with their stars undergoing slow internal evolution.  Model key requirement: fraction of gas mass lost by SNe-driven outflows is close to unity; then for a wide variety of infall histories of unprocessed baryonic matter to feed SF, most of the observed MDs can be well described by the model.  Model also predicts a relationship between the total stellar mass and the mean metallicity for dSphs in accord with properties of their DM haloes.  The model further predicts as a natural consequence that the abundance ratios [E/Fe] for elements such as O, Mg, and Si decrease for stellar populations at the higher end of the [Fe/H] range in a dSph.  Show that for infall rates far below the net rate of gas loss to SF and outflows, the MD in model is very sharply peaked at one [Fe/H] value, similar to what is observed in most globular clusters.  Suggests that globular clusters may be end members of the same family as dSphs.  

1202.3308

A systematic variation in the stellar IMF in early-type galaxies

Cappellari, McDermid, Alatolo, Blitz, ... et al

No consensus has emerged on whether IMF is universal in different galaxies.  Previous studies indicate that the IMF and the DM fraction in galaxy centers cannot be both universal, but they could not break the degeneracy between the two effects.  Recently, indications found that massive elliptical galaxies may not have the same IMF as our MW.  Report unambiguous evidence for a strong systematic variation of the IMF in early-type galaxies as a function of their stellar mass-to-light ratio, producing differences up to a factor of three in mass.  This was inferred from detailed dynamical models of the 2-dimensional stellar kinematics for the large Atlas3d representative sample of nearby early-type galaxies spanning two orders of magnitude in stellar mass.  Finding indicates that the IMF depends intimately on a galaxy's formation history.

1202.3349

Origin of strong B-fields in MW-like galactic haloes

Beck, Lesch, Dolag, Kotarba, Geng, Stasyszyn

(Use of Gadget simulations) A primordial magnetic seed field ranging from 1e-10 to 1e-34 G agglomerates together with the gas within filaments and protohalos.  There, it is amplified within 1e8 yrs put to equipartition with the corresponding turbulent energy.  THe magnetic field strength increases by turbulent small-scale dynamo action.  The turbulence is generated by the gravitational collapse and by supernova feedback.  Subsequently, a series of halo mergers leads to shock waves and amplification processes magnetizing the surrounding gas within a few 1e9 years.  At first, the B energy grows on small scales and then self-organizes to larger scales.  B-field strengths of 1e-6 G are reached in the center of the halo and drop to 1e-9 G in the IGM.  Analyzing the saturation levels and growth rates, the model is able to describe the process of B amplification notable well, and confirms the results of the simulations.

1202.3364

Origami constraints on the initial-conditions arrangement of DM caustics and streams

Neyrinck

In CDM, cosmological structure formation proceeds in rough analogy to origami folding.  Identify a result of origami mathematics that applies to cosmology.  Define caustics in the initial conditions (Lagrangian space) as surfaces on the sheet.  The regions outlined by the caustics, ("streams") may be colored according to two possible orientations of initial basis vectors--a severe restriction on connectivity.  Explore how outer caustics in Lagrangian space correspond to a Zeldovich prediction, as well as to a measurement from the recent ORIGAMI algorithm.

1202.3403

Dynamics of secular evolution

Binney

(Text of lecures to the "secular evolution of galaxies" Tenerife winter school.)  Connection between isolating integrals, quasi periodicity, and angle-action variables.  Phenomenon of resonant trapping, leading to chaos in cushy potentials and phase-space mixing in slowly evolving potentials.  Surfaces of section and frequency analysis introduced as diagnostics of phase-space structure.  Real galactic potentials include a fluctuation part that drives the system towards unattainable thermal equilibrium.  Two-body encounters are only one source of fluctuations, and all fluctuations will drive similar evolution.  Derive the orbit-averaged FP equation and relations that hold between the 2nd order diffusion coefficients and both the power spectrum of the fluctuations and the first-order diffusion coefficients.  ... whoa, too theoretical.