Day 20

Saturday.  Went shopping.  Sunday, back to work.


1106.3067
Influence of projection in cluster cosmology studies
Erickson, Cunha, Evrard


* 2d projection effects.


Measured cluster observable can be boosted depending on projection ["severely blended systems"?].  Projection causes mass-observable relation to go non-Gaussian in its scatter; model this and run Fisher forecasts: 5k sq.deg. to z=1.1 with threshold of M=1e13.7/h M_sun.  Use "blended fraction" motivated by optical cluster finding applied to Millenium sim.  Apply Planck / weak priors; bias in Omega_DE and w are 2~3 times previous forecast uncertainties.  Use 8 new DoF to describe cluster selection.  Priors at 5% level limits degradation to <10%.  Discuss strategies for using simulations and complementary observations to characterize the fraction of blended clusters and their mass selection properties.


* I guess they meant "blended clusters" when they said "blended systems."  That wasn't clear.


1106.3110
The Magellanic Quasars Survey:  II.  Confirmation of 145 enw AGN behind the southern edge of the LMC
Kozlowski, Kochanek, et al.


Quadrupled the number of QSO behind LMC from 55 to 200 via spectroscopy; 169 (145 new)/845 candidates in 4x3 deg. sq. fields south of LMC center.  Candidates selected based on IR color, X-ray, optical variability properties.  Non-QSO: young stellar objects (YSO), PNe, Be and blue stars, red stars.  401 with featureless spectra or low S/N for classification.  Good for quasar variability studies (cf. OGLE).   Completion of survey should result in ~700 well-monitored AGNs; could go up to 3600 AGNs.


* that was easy to understand.


1106.3113
The cometary cavity created by an aligned streaming environment/collimated outflow interaction
Lopez-Camara, Esquivel, Canto, Raga, Velazquez, Rodriguez-Gonzalez


* Hmm, not cosmology related.
* Mira: star with a comet-like tail.  oving unusually fast (130 km/s).  Material blowing off the red giant Mira is forming a wake ~13 light-years long.  Mira A is a variable red star, Mira B is a white dwarf 70 AU away at 1995 (~400 yr period binary), also has a protoplanetary disc.


Interaction "thin shell" model of biconical outflow and a streaming environment (aligned with the flow direction), as well as numerical sims (axisymmetric).  Similar to the situation at the head of the cometary structure of Mira B bipolar outflow.  Interaction is non-radiative; a rather broad jet/streaming environment interaction region is formed in sims; reasonably in agreement with analytic model.


* I guess they're talking about Mira B.


1106.3115
The impact of metallicity on the rate of SNIa
Kistler, Stanek, Kochanek, Prieto, Thompson


Propose: a natural consequence of the effects of metallicity is to significantly increase the SN Ia rate in lower-metallicity galaxies.  Low metallicity stars lead to higher-mass WD, which should be easier to bring to explosion.  Elevation in the rate of SNeIa in lower mass galaxies readily explained.  Models agree well with SNIa rates up to z~2.  Metallicity can also affect delay time distribution and super-Chandrasekhar SNe.


* I still don't quite get it--does high metallicity decrease the SN Ia rate?  That's what it sounds like, although the initial impression was different.  Confusing abstract.


1106.3196
Detection noise bias and variance in the power spectrum and bispectrum in optical interferometry
Gordon, Buscher


* what does optical interferometry have anything to do with power spectrum and bispectrum?
* I am not familiar with the topic, and the abstract is confusing the hell out of me.


Long-baseline optical interferometry uses the power spectrum and bispectrum constructs as fundamental observables.  [This isn't about galaxy power spectrum...  What is the power spectrum about?  Optical spectra?]   They did some simulation to improve the estimates.


* I guess they're talking about interferometry.  They want to calculate the correlation function and bispectrum (how do they do that? of the spectra?  of what?) without bias.  Certain noise assumptions cause bias, and they've tried to fix that.  I think that's the gist of this long abstract.


1106.3208
A simple empirically motivated template for the unresolved tSZ effect.
Efstathiou, Migliaccio


* template of... the gas profile?  What do they mean by unresolved?


Power spectrum of unresolved clusters of galaxies that arise from tSZ effect.  Based on a 'universal' gass pressure profile; includes parameter to describe departures from self-similar evolution.  Model consistent with Planck observations of the tSZ for X-ray clusters with z<1, also reproduces low amplitude of tSZ inferred from ground-based observations.  


* i wonder how reliable the "parameters to describe departures" are.  I guess they make it fit well.  What are the physical basis for it?  I guess it's empirically (from x-ray) motivated.


1106.3256
The mass-loss return from evolved stars to the LMC V.  The GRAMS carbon-star model grid
Srinivasan, Sargent, Meixner


* what?
* AGB (asymptotic giant branch) stars:  Region of the HR diagram populated by evolving low to medium-mass (0.6 to 10 M_sun) stars late in their life.  They appear as a red giant.  Characterized by a central and inert core of C and O, a shell where He is fusing into C, and another shell where H is fusing into He, and a large envelope of composition similar to normal stars.  AGB phase divided into two parts: Early AGB (He burning, red giant of 1AU radius) and the Thermally Pulsing AGB (He runs out, until H burning produces enough He, in which case He shell flash or thermal pulse occurs, lasts few 1000 years, mixes layers; with S-process generates half of the elements lighter than Fe nuclei.).   AGB are typically long period variables, and suffer a large mass loss.
* RSG (red supergiant) stars: luminous red stars of spectral type K or M.  Large volume (7AU radius), not so massive.  Ex. Betelgeuse and Antares.  Stars with >10M_sun become red supergiants while burning He.  Have cool surface temperatures (~3000K).


Total dust return rate from AGB and RSG outflow is an important component of galactic chemical evolution models.  Requires detailed radiative transfer modelling of individual stars.  New approach: use best-fit SED from a grid of dust shell models to determine luminosity and mass-loss rates for entire samples.  Present the carbon-star grid, compare with LMC carbon stars.  Generate spherically symmetric dust shell models.  Good agreement with SAGE observations.  


1106.3324
The color-magnitude relation of cluster galaxies: observations and model predictions
Jiminez, Castelli, Cora, Bassino


Origin of CMR relation in cluster galaxies studied with combination of N-body SPH and galaxy formation SAM.  Compared with photometric properties of early-type galaxies in Antilia cluster.  Good agreement between observations and simulation.  Can be use to unvail the physical process that yield the tight observed CMR.


* What is the Antlia cluster?  Antlia is a constallation ("air pump") in the southern sky.
* what is CMR?  -- the color-mag relation that shows the red sequence, the blue cloud, and the green valley.


1012.1293
Intergalactic Filaments as Isothermal gas cylinders
Harford, Hamilton


Cosmo simulation at z=5.  Find intergalactic filaments form isothermal gas with delta~500, T~1-2e4K (just above lyman alpha cooling floor).  Hydrodynamic properties of gas more important than DM in determining this structure.  Temperature and ionization state of gas completely determine a finite total mass per unit length of an isothermal cylinder.  Implications for understanding the "cold mode" mechanism of gas transport into galaxies.


* filaments with isothermal gas!  can it have star formation?
* Lyman alpha cooling: H falls from n=2 to n=1, emits photon, cools (I guess).
* it was unclear--do the gas in the cylinder cool or not?


1012.4515
PPPC 4 DM ID: A Poor particle physicist cookbook for DM indirect detection
Cirelli, Corcella, Hektor, Hütsi, Kadastik, Panci, Raidal, Sala, Strumia


List ingredients and recipes for computing signals of TeV-scale DM annihilations and decays in the Galaxy and beyond.  Energy spectra of e-, e+, p-, Dbar, gamma, nu, nubar, e, mu, tau at production, with high-statistic simulations.  Then provide propagation function for charged particles in the Galaxy for several DM profiles and sets of propagation parameters.  Compute the energy spectra of e- and e+, p- and Dbar observed at Earth.  Gamma ray fluxes, prompt emission and from inverse Compton in the galactic halo.  Provide spectra of extragalactic gamma rays.  All results available in numerical form.


* Is this useful?  Does it match any observations (yet)?