Day 167

Friday.  Caught a cold, working hard.  Must read Gary's paper to work with Tim.  Helping Zahra debug.  Astroph was offline for 4 days out of 5 this week, and now we have 76 papers today.  I am nearly 2 weeks behind.


1112.5664
Multi-GeV Neutrino emission from magnetized gamma ray bursts
Gao, Meszaros


Neutrino emissivity from nuclear collisions in magniteically dominated collisional models of gamma-ray bursts: results indicate that significant mutli-GeV neutrino fluxes are expected for typical EM detected bursts.  For detecting at least one muon event in Icecube and Deep Core sub-array, a single burst must be near the high end of the luminosity function, and at z<0.2.  Calculate luminosity and distance ranges that can generate 0.01 to 1 muon event per GRB.


* if the GRB is bright and nearby, then Icecube might be able to detect one muon event from its neutrino emission.

Day 166

Thursday---already.  I worked all day yesterday.  Caught a cold, just like dad.  I'm still a full week behind on Astro-ph!  I'm also getting used to using the dishwasher--not sure if that's a good sign.

1112.3771

Outer disks of lentitular galaxies

Silchenko

Study stellar population properties along the radius in 15 nearby S0s: find outer stellar disks are old (8-15 Gyr), being often older than bulges.  S0 formation theory (quenched SF in spiral galaxies) questioned.

1112.3809

Modeling the spectra of (BAL) QSOs

Higginbottom, Long, Knigge, Sim

Model QSO spectra, investigate the plausibility of geometric unification.  For reasonable geometries and mass loss rates, able to produce synthetic spectra which reproduce the features of BALQSO spectra.

1112.3824

Chemical evolution of the MW: the origin of phosphorus

Cescutti, Matteucci, Caffau, Francois

Abundance of P measured in disk stars.  Predict chemical evolution of P in MW and compare results with observation to put constraints on the P nucleosynthesis.  Adopt two-infall model [?], compute the evolution of abundances of P and Fe.  Adopt stellar yields for these elements from different sources.  P should have been formed mainly in Type II SNe.  Fe mainly in Ia SNe.  Results: confirm that, to reproduce the observed trend of [P/Fe] vs [Fe/H] in disk stars, P is formed mainly in massive stars.  But in order to reproduce the data, the massive stars should produce x3 more P than predicted.  Conclude: available yields from P from massive stars are largely underestimated, nucleosynthesis calculations should be revised.  Predict [P/Fe] expected in halo stars.

1112.3860

Detection of HF emission from the Orion Bar

van der Tak, Ossenkopf, Nagy, Faure, Roellig, Bergin

Conclude that HF emission is a signpost of molecular gas with high electron density.


* HF line signpost of molecular gas + high electron density (plasma).

1112.3875

The cenetral PNe populations of external galaxies with SAURON

Sarzi

PNe in M32 and M31: lack of bright PNe in the nuclear regions of M31 is likely linked to the nearly Solar value for the stellar metallicity, consistent with suggestions that a larger metallicity would bias the horizontal-branch (HB) populations toward bluer colors, with fewer red HB stars capable of producing PNe and more HB stars contribute to the far UV that is observed in metal-rich early-type galaxies, as well as in the nucleus of M31.

*  blue HB stars generate far UV radiation.


1112.3889
Fullerenes and proto-fullerenes in interstellar carbon dust
Duley, Hu


What was thought to be C60 emission lines are actually from precursor molecules in hydrogenated amorphous carbon (HAC).


1112.3893
The X-ray properties of Cataclysmic variables
Balman


Cataclysmic variables (CVs) are a distinct class of X-ray binaries transferring mass from a donor star to a compact star accretor (WD).  A lab for accretion physics, mechanisms and disk theory with dynamics of outflows and interaction with surrounding medium.  More data on accretion shocks and boundary layers with high sensitivity instruments and/or grating X-ray spectroscopy with high resolution, yielding temperature and velocity diagnostics.  Time resolution utilizes accretion mode diagnostics, characterizing the variability of the gas flow in disks.  Review Intermediate Polars, Dwarf Novae and Classical/Recurrent Novae.


1112.3895
Constructing regularized cosmic propagators
Bernardeau, Crocce, Scoccimarro


New scheme for general computation of cosmic propagators that allow interpolation between standard perturbative results at low-k and their expected large-k resummed behavior.  [what is a propagator?]  Generic prescription for multi-point propagators provides the necessary building blocks for computation of polyspectra in the context of "Gamma-expansion" (by Bernardeau+ 08).  Apply to calculation of the matter bispectrum at one-loop order.


1112.3897
Inflationary magnetic fields spoil the homogeneity and isotropy of the Universe
Bonvin, Caprini, Durrer


As the title says.


1112.3901

Magnetic fields from inflation: the fatal transition to the radiation era
Bonvin, Caprini, Durrer


Same as above.


1112.3903
An estimate of the temporal fraction of cloud cover at San Pedro M'artier Observatory
Carasco, Carraminana, Sanchez, Avila, Cruz-Gonzalez


Find 82.4 % of the time the sky is clear of clouds at this site.  


1112.3911
Galactic sources of high-energy neutrinos: Highlights
Vissani, Aharonian


Overview of high-energy neutrinos from galactic sources, transparent [?] to their gamma-ray emission [?].  Focus on young SNe remnants.  Consider possibility of detecting neutrinos from other strong galactic gamma-ray sources, such as Vela Junior, Cygnus Region and Fermi Bubbles.  Quantify the impact of large theta_13 on high-energy neutrino oscillations.


1112.3917
Detection of very high energy gamma-ray emission from NGC 1275 by the MAGIC telescopes
MAGIC collaboration, Lombardi, Colin, Hildebrand, Zandanel


VHE gamma-ray emission (E>100 GeV) from NGC 1275, the central radio galaxy of the Perseus cluster of galaxies.  Fermi-LAT measured spectra above 100 MeV.  Indicates a break or cut-off around ~10s GeV in the spectrum.  E > 100 GeV does not show variability in the month timescale.  Non-detection of radio galaxy IC 310.  VHE has a variability timescale of ~a year.


* Reynolds Number: ratio of inertial force to viscous force in a fluid flow around an object (of dimension D).  Higher the Reynolds number, the more small-scale eddies one will see; the largest-scale eddies are set by the dimension D.  Reynolds number can be thought of the range of the scale of eddies--higher Reynolds number, less viscosity to damp eddy, and more small-scale eddies will form.

Day 165

Tuesday.  Saw parents off to Düsseldorf flughafen.  Read up on German grammar on the way back, and learned a bit more: Diese, mine, jede, ...  I gotta study more German.  Wednesday.  Internet connection at home (fast!)--Thanks, Alice Help Desk!  Proper lights on the ceiling!  Mirror on the entrance wall!  Thanks, Herr Hentschel!  You're the best landlord.  Okay, gotta get back to Astro-ph daily reading.


(**)1112.3652
Understanding better (some) astronomical data using Bayesian methods
Andreon


* This 18 page example of use of JAGS (Just Another Gibbs Sampler) for e.g. cluster mass measurement data with intrinsic scatter, etc, is a good read.  I should present it.


1112.3654
Rapid, Machine-Learned Resource Allocation: Application to High-redshift GRB Follow-up
Morgan, Long, Richards, Broderick, Butler, Bloom


Rapid identification of high-z candidates using early-time metrics from 3 telescopes onboard Swift, using Random forest Automated Triage Estimator (RATE).  Train with 135 Swift bursts of known z, only 18 of which are z>4.  Cross-validate, ~56% of high-z bursts can be captured from following up the top 20% of the ranked candidates, ~84% from the top 40%.  


* Random forest machine learning technique: ensemble classifier that consists of many decision trees and outputs the class that is the mode of the class's output by individual trees.  Constructs a collection of decision trees with controlled variation.  Many advantages, but tends to overfit to noise.


1112.3655
The Gemini Cluster Astrophysics spectroscopic survey (GCLASS): the role of environment and self-regulation in galaxy evolution at z~1
Muzzin, .. Hoekstra, ... van Dokkum, et al


For log(M*/Msun)>9.3 galaxies, the well-known correlation between environment and properties are in place at z~1.  Post-starbursts highly correlated with high-density environment + lack of correlation between sSFRs and Dn(4000)s of SF galaxies with their environment indicate that at z~1 the environmental-quenching timescale must be rapid.  Modeling show that self-quenching dominates over environmental quenching at z>1.  [what is self-quenching?]


1112.3704
NIR Spectroscopy of SF galaxies at z~1.4 with Subaru/FMOS: The mass-metallicity relation
Yabe, et al


Mass-metallicity relation obtained at z~1.4 is that between z~0.8 and z~2.2, with intrinsic scatter of >0.1 dex.  Galaxies with higher SFR and larger half-light radii show lower metalicities at a given stellar mass.  Reason for trend: perhaps infall of pristine gas accreted from IGM or merger events.  Compilation of mass-metallicity relations from 0.1<z<3 show they evolve smoothly over z without changing the shape, except for the most massive part at z~0.


1112.3710
Formation of massive globular clusters with heavy element abundance spread in the Galacitic building blocks
Bekki


GC that show abundance spread in heavy elements (e.g., Fe) are becoming common in recent observations.  Galactic GCs with heavy element abundance spread ("HEAS"): investigate formation processes of massive GCs (MGCs) > 1e6 Msun in gas-rich dwarf galaxies interacting and merging with a young Galaxy.  Massive and compact stellar clumps that are developed through merging of gaseous regions initially at different regions and thus with different metallicities--hence MGCs formed in dwarfs have HEAS is inevitable.  


1112.3769
SZ clusters in Millennium Gas simulations
Kay, ... Liddle, et al


Study SZ cluster population at low and high z, for 3 models with varying gas physics; intrinsic Y500-M500 relation has very little scatter, is insensitive to cluster gas physics and evolves to redshift one in accord with self-similar expectations.  Pre-heating and feedback models predict scaling relations in excellent agreement with Planck and XMM-Newton data.  Assess importance of projection effects from LSS along LoS; find integrated SZ signal is unbiased wrt the underlying clusters.  SZ hot-gas pressure contributes largest from radii close to r500.  

Day 164

Sunday.  Went to Hello Vietnam with Mom and Dad--an excellent restaurant.  Dad caught a cold with a fever of 38 C, is in bed. Made excellent grilled chicken leg, as we did last night.  Delicious, but it makes the apartment smell of chicken smoke!


1112.3713
An MCMC determination of the primordial helium abundance
Aver, Olive, Skillman


Estimating the primordial helium abundance: spectroscopic observations of chemical abundances in metal-poor H II regions.  Physical parameters of H II region: electron density, electron temperature, reddening, and the ratio of He to H ("y").  Customary to estimate or self-consistently determine these parameters to calculate y.  Frequentist analyses of the parameter space have been shown to be successful in these determinations, and MCMC techniques have proven to be very efficient in sampling this parameter space.  But accurate determination of primordial He from observing H II regions is constrained by both systematic and statistical uncertaities.  To reduce the latter and better characterize the former, apply MCMC methods to the large dataset recently compiled by Izotov, Thuan, Stasinska (07).  Variety of cuts explored, for better quality data.  First examine efficacy of the He I 4026 emission line as a constraint on the solutions, show systematic bias in its absence.  As a clear measure of the quality of the physical solution, a chi2 analysis proves instrumental in the selection of data compatible with the theoretical model.  In addition, the method also allows to exclude systems for which parameter estimations are statistical outliers.  As a result, the final selected dataset gains in reliability and exhibits improved consistency.  Regression to zero metallicity yields Y_p = 0.2534 pm 0.0083, in broad agreement with the WMAP result.  The inclusion of more observations show promise, but require high quality spectra.


1112.3769
SZ clusters in Millenium gas simulations
Kay, Peel, ... et al


Study SZ cluster population at low and high redshift using large-volume Millenium Gas N body hydro sims, for 3 models with varying gas physics.  Confirm: intrinsic (spherical) Y500-M500 relation has very little scatter (sigma_log10Y ~ 0.04), is insensitive to cluster gas physics and evolves to redshift one in accord with self-similar expectations.  Pre-heating and feedback models predict scaling relations that are in excellent agreement with the combined Planck and XMM-Newton data.  Agreement largely preserved when r500 and M500 are derived using hydrostatic mass proxy, Y_X,500, but with significantly reduced scatter--a result that is due to the tight correlation between Y500 and Y_X,500.  This assumption also hides any bias in the relation due to dynamical activity.  Assess the importance of projection effects from LSS along the LoS, by extracting cluster Y500 values from fifty simulated 5x5 square degree sky maps.  Once the (model-dependent) mean signal is subtracted from the maps, find that the integrated SZ signal is unbiased with respect to the underlying clusters, although the scatter in the (cylindrical) Y500-M500 relation increases in the pre-heating case, where a significant amount of energy was injected into the IGM at high redshift.  Study the hot gas pressure profiles to investigate the origin of the SZ signal and find that the largest contribution comes from radii close to r500 in all cases. The profiles themselves are well described by generalised NFW profiles but there is significant cluster-to-cluster scatter.


(*)1112.4040
Weak gravitational lensing effects on cosmological parameters and DE from gamma-ray bursts
Wang, Dai


GRBs can constrain cosmology with high-z information.  But the apparent magnitude of distant GRBs can be distorted by lensing from LSS along LoS.  Investigate lensing effect on cosmological parameters and DE EoS from GRBs.  First calibrate the GRB luminosity relations without assuming any cosmological models.  Luminosity distances of low-z GRBs were calibrated with the cosmography method using SNe Ia sample.  Find that the gravitational lensing has non-negligible effects on the determination of DE and cosmo parameters.  Because high-z GRBs are more likely to be reduced, the most probable value of the observed matter density Omega_m will shift from 0.30 to 0.26 after including the gravitational lensing effect; also shifts w to a more negative value.  Constratin DE EoS out to z~8 using GRBs, and find that the EoS deviates from LCDM at 1 sigma CL, but agrees with w=-1 at the 2 sigma CL.


(*)1112.4229
What do DM properties tell us about their mass assembly histories?
Wong, Taylor


Individual DM haloes in simulations vary widely in: shape, rotation, substructure and degree of internal relaxation.  PCA analyses suggest that a few PC explain a large fraction of the scatter in halo properties.  The main principal component is closely linked with concentration, which in turn is known to be related to the mass accretion history of the halo.  Examine here more generally the connection between mass accretion history and structural parameters.  The space of mass accretion histories has principal components of its own.  Find: the strongest two components can be interpreted as the overall age of the halo and the acceleration or deceleration of growth at late times.  These 2 components account for ~70% of the scatter in mass accretion histories, however, due to the stochastic effect of major mergers.  Relating structural parameters to formation history, find that concentration correlates strongly with the early history of the halo, while relaxation correlates with the late history.  Examine the inferences about formation history that can be drawn by splitting haloes into subsamples, based on observable properties such as concentration and shape at some final time.  This approach suggests interesting possibilities, such as the possibility of defining young and old samples of galaxy clusters in a rigorous, quantitative way, or testing the dynamical assumptions of galaxy formation models empirically.


1112.4329
Solar flares as harbinger of new physics
Zioutas, et al


Provide additional evidence on the involvement of exotic particles (axions and/or other WISPs) from measurements of the quietest Sun and flaring Sun.  Solar chameleons remain a viable candidate, since they may preferentially convert to photons in outer space.


(*)1112.4347
A significant problem with using the Amati relation for cosmological purposes
Collazzi, Schaefer, Goldstein, Preece


Consider the distribution of many samples of GRBs when plotted in a diagram with their bolometric fluence (Sbolo) vs the observed photon energy of peak spectral flux (Epeak,obs).  In this diagram, bursts that obey the Amati relation must lie above some limiting line, although observational scatter is expected to be substantial.  Confirm that early bursts with spectroscopic redshifts are consistent with this limit.  But find that the bursts from BATSE, Swift, Suzaku, and Konus are all greatly in violation of the limit.  Find that every satellite has a greatly different distribution, requires that selection effects are dominating these distributions.  For detector selections, the trigger threshold and the threshold to measure Epeak,obs combine to make a diagonal cutoff, with the position of this cutoff varying greatly detector to detector.  For selection effects due to the intrinsic properties of the burst population, the distribution of Epeak,obs makes for bursts with low and high values to be rare, while the fluence distribution makes bright bursts uncommon.  For a poor threshold, the combination of selection effects serves to allow only bursts within a region along the limit to be measured; these bursts then appear to follow an Amati relation.  Therefore, the Amati relation is an artifact of selection effects within the burst population and the detector.  Therefore, the Amati relation should not be used for cosmological tasks.  This failure is in no way prejudicial against the other luminosity relations.


1112.4386
Comment on "The Real Problem with MOND" by Scott Dodelson, arXiv:1112.1320
Moffat, Toth


Point out that BAO, while predicted by theories that do not incorporate collisionless CDM, are strongly suppressed by the statistical window function that is used to process finite-sized galaxy samples.  Assert that with present-day data sets, the slope of the matter power spectrum is a much stronger indicator of a theory's validity.  Also agrue that MOND should to be used as a strawman theory as it is not in general representative of modified gravity theories; some theories, notably SVT MOG, offer much more successful predictions of cosmological observations.


(*)1112.4444
The 400d galaxy cluster survey WL programme: II: Weak lensing study of seven clusters with MMT/Megacam
Israel, Erben, Reiprich, Vikhlinin, Sarazin, Schneider


Evolution in the mass function of galaxy clusters sensitively traces both the expansion history of the Universe and cosmological structure formation.  Robust cluster mass determinations are a key ingredient for a reliable measurement of this evolution, especially at high z.  WL is a promising tool for, on average, unbiased mass estimates.  The WL project aims at measuring reliable WL masses for a complete X-ray selected sample of 36 high z (0.35<z<0.9) clusters.  The goal of this paper is to demonstrate the robustness of the methodology against commonly encountered problems, including pure instrumental effects, the presence of bright (8-9 mag) stars close to the cluster center, ground based measurements of high-z (z~0.8) clusters, and the presence of massive unrelated structures along the LoS.  Select a subsample of 7 clusters observed with MMT/Megacam.  Instrumental effects are checked in detail by cross-comparision with an archival CFHT/MegaCam observation.  We derive mass estimates for 7 clusters by modelling the tangential shear with an NFW profile, in two cases with multiple components to account for projected structures in the LoS.  Firmly detect lensing signals from all 7 clusters at more that 3.5 sigma and determine their masses, ranging from 1e14 Msun to 1e15 Msun, despite the presence of nearby bright stars.  Retrieve the lensing signal of more than one cluster in the CL 1701+6414 field, while apparently observing this cluster through a massive foreground filament.  Also find a multi-peaked shear signal in CL 1641+4001.  Shear structures measured in the MMT and CFHT images of CL 1701+6414 are highly correlated.

Day 163

Saturday, Christmas Eve.  Since Tuesday, the day my parents arrived (at 11pm on Dec. 20th), I have: (1) scratched the Avis car, drove to and back from Düsseldorf, (2) shopped at IKEA with Mom and Dad with said car, (3) returned car and paid 850 Euro for the scratch, then went to Siegburg Christmas market, then to Bonn Christmas market, (4) called Alice O2 to describe my Internet connection problem, then went to Köln Christmas market, then Bonn's again, (5) and today had a panic about losing my green shoulder bag with my passport inside, where it was it my closet all along, and afterwards going to IKEA again to return some unused stuff, and buy some more stuff.  Most of the time I was in a bad mood, yelling at Mom (sorry Mom).  

1112.3668

M94 as a unique testbed for BH mass estimates and AGN activity at low luminosities

Constantin, Seth

Nucleus of M94: broad Ha emission measurements is unambiguously associated with the high-resolution X-ray, radio, and variable UV sources detected at the optical nucleus of this galaxy. Suggest that it is one of the least luminous broad-line (type-1) LINERs.  SMBH mass estimates based on kinematics (~7e6 Msun) agrees with fundamental plane and M-sigma relation, but is discrepant from "other accretion based estimate" (M-FWHM(Ha) relation, BH mass with highly-ionized mid IR emission lines, and X-ray excess variance), which give much lower estimates (1e5 Msun).  AGN in this system may be deficient in ionizing radiation relative to the observed emission-line activity, possibly due to source variability or the superposition of multiple sources including SNe.

1112.3683

The BOSS emission-line lens survey (BELLS). I.  A large spectroscopically selected sample of lens galaxies at redshift ~ 0.5

Bolton, Schlegel, Eisenstein, Kochanek, Connolly, ... et al

Same detection method as SLACS, 25 definite and 11 probable SL gravitational lens systems by galaxies.  SIS ellipsoid model parameters of definite lenses.  From 6 month data; more from the full 5-year BOSS data set (~100s), can constrain the z evolution of structure of elliptical, bulge-dominated galaxies as a function of luminosity, SM, and rest-frame color, providing test for galaxy formation and evolution.

Day 162

Tuesday.  Parents -- supposed to have arrived by now (8pm), but still stuck in Frankfurt, so that they can fly to Düsseldorf.  Rented a car, scratched the sides.  Got the telephone company to come, but the DSL/WLAN box doesn't seem to work.  Zahra agreed to sit at my apartment for 2 hrs, which I was grateful for (although it ended up being unnecessary).  Let's see how much reading I get done this week.


1112.3957
Strengthening the open cluster distance scale via VVV photometry
Majaess et al


~14% of open clusters possess 20% absolute error on distance estimates, evaluated from n>3 independent distance estimates; age estimates markedly worse.  Impedes efforts such as calibrating standard candles and constraining masses for substellar companions.  VVV JHK photometry can reduce uncertainty to <10%, demonstrated on NGC 4349 and Pismis 19, which show 60% uncertainty in previous works (>5x reduction in uncertainties).  Indicates (i) existing parameters for the substellar object NGC 4349 127b require revision, partly because new data implies that the host is 20% less massive, (ii) R Cru is not a member of NGC 4349 and should be excluded from period-Wesenheit calibrations that anchor the distance scale, (iii) results for Pismis 19 underscore the advantages from deep VVV JHKs data to examine obscured (Av~4) and differentially reddened intermediate-age clusters.


1112.3958
Old massive globular clusters and the stellar halo of the dwarf starburst galaxy NGC 4449
Strader, Seth, Caldwell


Nearby dwarf starburst galaxy NGC 4449 has an unusual abundance of luminous red star clusters, some of which are old globular clusters with intermediate metallicities ([Fe/H] ~ -1) and subsolar Mg enhancement ([Mg/Fe]~ -0.1 to -0.2).  One of these clusters may be the nucleus of a tidally distrupting dwarf galaxy; the other is very massive (3e6 Msun).  Identified a population of remote halo globular clusters.  Consistent with an emerging picture of the ubiquity of stellar haloes among dwarf galaxies, studies may help distinguish between accretion and in situ scenarios for such halos.

Day 161

Monday.  Got some work done over the weekend: helped Zahra "start" her paper, and listened to Peter G. about his problems with his project; I was also going to read Cosmo lecture notes, but I ended up debugging my PhotoZGGLens (and related) code instead.


1112.3652
Understanding better (some) astronomical data using Bayesian methods
Andreon


Astronomical data: heteroscedastic (point-dependent) errors, intrinsic scatter, selection effects, data structure, non-uniform populations (Malmquist bias), non-Gaussian data, upper/lower limits.  Show how to model all these features using Bayesian methods: formalize the logical link between the involved quantities, how the data arise and what is already known on the quantities studied.  The posterior probability distribution summarizes what has been learned from data.


1112.3653
Spitzer IRAC identification of HErschel-ATLAS SPIRE sources
Kim et al


Use Spitzer-IRAC (3.6 and 4.5 um) data to identify NIR counterparts to submillimeter galaxies detected with Herschel-SPIRE (250um) over ~0.4 deg. sq.  Identify 123 SPIRE sources out of the 159 in the IRAC coverage area.  Compared to the field population, the SPIRE counterparts occupy a distince region  of color-magnitude space: use this to identify further 23 counterparts to 13 SPIRE sources.  IRAC identification rate of 86% is pretty high compared to WF ground-based optical and NIR imaging of Herschel fields.  False id rate estimated at 4% (4 or 5 sources).  ~40% of identified SPIRE galaxies are likely to be high redshift (z>1.4) sources, based on SDSS data.


1112.3655
The Gemini Cluster astrophysics spectroscopic survey (GCLASS): the role of environment and self-regulation in galaxy evolution at z~1
Muzzin, Wilson, Yee, Glibank, Hoekstra, ... van Dokkum, Franx ... et al


Evaluate the effects of environment and stellar mass on galaxy properties at 0.85<z<1.2.  For galaxies with log(M*)>9.3, the well-known correlations between environment and properties (f_SF, SFR, sSFR, D(4000), colors) are already in place at z~1.  SF and quiescent galaxy's properties are determined primarily by their stellar mass, not by their environment.  The environment's primary role is to control the fraction of star-forming galaxies.  Post-starburst galaxies with 9.3<logM*<10.7 are 3x more common in high-density regions compared to low-density regions.  Clear association of post-starbursts with high-density regions as well as the lack of a correlation between sSFR and D(4000)s of SF galaxies with their environment suggests that at z~1 the environmental-quenching timescale must be rapid.  Construct a simple quenching model which demonstrates that the lack of correlation between D(4000) of quiescent galaxies and their environment results naturally if self quenching dominates over environmental quenching [what's the difference?] at z>1, or if the evolution of the self-quenching rate mirrors the evolution of the environmental-quenching rate at z>1, regardless of which dominates.


1112.3656
Spectroscopy of the spatially-extended Lya emission around a QSO at z=6.4
Goto, ... Miyazaki, Yamauchi et al


Deep moderate-resolution Keck/Deimos spectra of a QSO at z=6.4.  Shows spatially-extended component (more than a stellar spectrum) of Lya emission, and a continuum part.  Extended component has LW of 21A, smaller than that of QSO (52A).  First such observation.  Emission may be from the theoretically infalling gas in the process of forming a primordial galaxy that is ionized by a central QSO.  If it's gas photoionized by the host galaxy, then the SFR rate of >3Msun/yr is required.  Assuming virialized gas, the dynamical mass estimate of the gas is 1.2e12 Msun.  The derived MBH/Mhost is 2.1e-4, two orders smaller than those from more massive z~6 QSOs and places the galaxy in accordance with the local M-sigma relation.  


1112.3658
Analytic gas orbits in an arbitrary rotating galactic potential using the linear epicyclic approximation
Pinol-Ferrer, Lindbald, Fathi


Simulate the motion of interstellar matter (and to damp the Lindbald resonances), introduce a friction which is proportional to the deviation from circular velocity, also damp corotation resonance.  Program produces orbital and density maps, as well as line of sight velocity maps for a chosen orientation of the galaxy.  Compare results with previous simulations and observations from literature, gives satisfactory agreement.  Program should be a useful complement to elaborate numerical simulations.


1112.3659
Evolution of the merger induced hydrostatic mass bias in galaxy clusters
Nelson, Rudd, Shaw, Nagai


Examine the effects of mergers on the hydrostatic mass estimate of galaxy clusters using high-resolution Eulerian cosmo simulations.  Find major merger using merger trees, follow the time evolution of the hydrostatic mass bias as the systems relax.  Enables to characterize the dynamical state of clusters more robustly and quantitatively than morphological classification. Find: in major merger, a shock propagates outward from the parent cluster, resulting in a large overestimate in the hydrostatic mass bias.  After the merger, as a cluster relaxes, the bias in hydrostatic mass estimate decreases but remains at a level of 5-10% with 15-20% scatter.  Investigate the post-merger evolution of the non-thermal pressure support (a dominant cause of residual mass bias).  At r500, the contribution from non-thermal pressure support peaks at 30% of the total pressure during the merger and quickly decays to ~10-15% as a cluster relaxes.  Additionally, use a measure of the non-thermal pressure [what could that be?] to correct the hydrostatic mass estimate.  After 4Gyr of the major merger, the direct effects of the merger event on the hydrostatic mass bias have become negligible.    Thereafter, the mass bias is primarily due to residual bulk motions in the gas which are not accounted for in the hydrostatic equilibrium equation.  Present a hydrostatic mass bias correction method that can recover the unbiased cluster mass with 8% scatter at r500 and 11% scatter in the outskirts, within r200.


* non-thermal contribution from bulk motions and turbulence messes up the hydrostatic equilibrium (HSE) assumptions in estimating mass; in X-rays, the mass using HSE systematically underestimates the total cluster mass by 10-20% even in relaxed clusters.  HSE mass derived from Chandra is biased low compared to WL mass.  
* mass correction requires knowledge of rho_gas, P_th(r), and dP_th/dr.  So it's for mass estimates using gas density and temperatures.

Day 160

Friday already.  Yesterday was our last German class.  Went to Dani (Kübler)'s farewell dinner afterwards.  I'm glad I took her to the Anime Art Exhibition.


0803.1265
Five more massive binaries in the Cygnus OB2 association
Kiminki, Kobulnicky, Gilbert, Bird, Chunev


Present orbital solution for four OB spectroscopic binaries, and a partial solution to the B spectroscopic binary, as part of an ongoing study to determine the distribution of orbital parameters for binaries in the Cygnus OB2 association.  Of the now 18 known oB binaries in Cyg OB2, 14 have periods and mass ratios.  Distribution of log(P) is flat and consistent with Oepik's law.


* Oepik's law: 
* Cyg OB2: one of the largest young clusters of stars in our Galaxy.  Embedded in a wider SF region known as Cygnus X.  10x more massive than the Orion, but obscured behind a massive dust cloud known as the Cygnus Rift. Home to many massive binaries.


1112.3340
The stellar and sub-stellar IMF of simple and composite populations
Kroupa, Weidner, Pflamm-Altenburg, Thies, Dabringhausen, Marks, Maschberger


The current knowledge on stellar IMF documented.  Usually described as being invariant, but appears to become top-heavy when SF rate density surpasses about 0.1 Msun/(yr pc^3) on a pc scale, and may become increasingly bottom-heavy with increasing metallicity.  Ends quite abruptly below about 0.1 Msun with brown dwarfs (BDs) and very low mass stars having their own IMFs.  The most massive star of mass mmax formed in an embedded cluster with stellar mass Mecl correlates strongly with Mecl being a result of gravitation-driven but resource limited growth and fragmentation induced starvation.  There is no convincing evidence whatsoever that massive stars form in isolation.  Massive stars form above a density threshold in embedded clusters which become saturated when mmax ~ 15o Msun which appears to be the canonical physical upper mass limit of stars.  Super-canonical massive stars arise naturally due to stellar mergers induced by stellar-dynamical encounters in very young dense clusters.  Various methods of discretising a stellar populations are introduced:  optimal sampling leads to a mass distribution that perfectly represents the exact form of the desired IMF and the mmax-Mecl relation, while random sampling results in statistical variations of the shape of the IMF.  Since observation shows less statistical variations, optimal sampling may be more realistic description of star formation.  Composite populations on galaxy scales, which are formed from many pc scale star formation events, need to be described by the integrated galactic IMF. This IGIMF varies systematically in dependence of galaxy type and SFR, with dramatic implications for theories of galaxy formation and evolution.


1112.3342
The Hydrodynamic origin of NS kicks
Nordhous, Brandt, Burrows, Almgren


Axisymmetric core collapse SNe simulations in which hydrodynamic recoil from an asymmetric explosion produces large proto-neutron star (PNS) velocities.  Use AMR code CASTRO to self-consistently follow core-collapse, the formation of the PNS and its subsequent acceleration.  Obtain recoil velocities up to 620 km/s at ~1s after bounce.  Velocities consistent with observed distribution of pulsar kicks and with PNS velocities obtained in other theoretical calculations.  PNSs still accelerating at several hundred km/s at the end of calculations, suggesting that even the highest velocity pulsars may be explained by hydrodynamic recoil in generic, core-collapse SNe.


1112.3348
The Herschel Exploitation of local galaxy Andromeda (HELGA).  I: Global far-infrared and sub-mm morphology
Fritz et al


Main goals of HELGA: to study the characteristics of the extended dust emission, focussing on large scales and higher resolution, and the obscured star formation.  Separate FIR morphology from M31 to the foreground Galactic cirrus.  Detect 3 ring-shaped structures extending out to 21, 26 and 31 kpc respectively, in the south-western part of M31, with the innermost structure also having a counterpart at the opposite side; also confirmed by detection in HI maps.  Find dust in M31 significantly extends beyond the previously mapped FIR emission.  


1112.3447
The roles of radiation and ram pressure in driving galactic winds
Sharma, Nath


* ram pressure: pressure exerted on a body which is moving through a fluid medium, causing a strong drag force on the body.  In the case of a galaxy moving through the intergalactic gas, the ram pressure is capable of stripping the galaxy of much of its interstellar gas.


Study gaseous outflows from disk galaxies driven by the combined effects of ram pressure on cold gas clouds and radiation pressure on dust grains.  Taking into account the gravity due to disk, bulge and DM halo, and assuming continuous SF in the disk, show that radiation or ram pressure alone is not sufficient to drive escaping winds from disk galaxies, both processes contribute.  Wind speed in galaxies with SFR < 100 Msun/yr has larger contribution from rampressure; in high mass galaxies with large SFR, radiation from the disk has a greater role in driving galactic winds.  Ratio of wind speed to circular speed can be approximated as xxx.  Show that this conclusion is borne out by observations of galactic winds at low and high redshift and also of circumgalactic gas.  Estimate mass loading factors under the combined effect of ram and radiation pressure, and show that the ratio of mass loss rate to SFR scales roughly as vc^-1 Sigma_g^-1, where Sigma_g is the gas column density in the disk.


1112.3497
Site testing at astronomical sites: seeing evaluation from satellite based data
Ortolani, Zitelli


Use IR night time data of GOES 12 satellite to estimate the seeing using remote sounding.  Correlation between satellite derived values and analysis of sites located at Cerro Paranal and Roque de los Muchachos is about 90%.  The correlation from the afternoon data and the following night allows forecast of the photometric night quality.

Day 159

Thursday.  Found out about Phillipe's health yesterday.  Saw another green shooting star last night, after playing Uno at Fiddlers with Zahra and Hananeh.  Today will be a busy afternoon with meetings, get work done in the morning (but it's already 9am).


1112.3037
The cluster of class I/f/II YSOs discovered near the Cepheid SU Cas
Majess, Turner, Gieren


Cluster of YSOs in the field of the classical Cepheid SU Cas: IR images reveal that cluster deviates from spherical symmetry and exhibits an apparent diameter of 3x6'.  SEDs constructed from IR photometry indicate that I/f/II class objects lie within r<3'.  Approximately 50% of the class I sources within r<3' were classified solely using WISE photometry due to the absense of detections by 2MASS.


* Cepheids, classical (Pop I Cepheids): very regular pulsation period of the order of days to months, M ~ 4-20 Msun, up to 100,000x more luminous.  Yellow supergiants of F6-K2 and their radii change by millions of kilometers in pulsations.  
* Cepheids, Type II (Pop II Cepheids): Pulsate with period of 1-50 days.  Typically metal-poor, old (~10 Gyr), low mass objects (0.5 Msun).  
* Dynamics of the pulsation: Eddington valve (kappa-mechanism), where kappa = gas opacity.  Doubly ionized helium is more opaque than singly ionized helium.  Heating ionizes, star is opaque, heated by star's own radiation, and the increase in T causes the star to expand.  As it expands, it cools, becomes more transparent, allows radiation to escape, expansion stops.  


1112.3038
A global physical models for cepheids
Pejcha, Kochanek


Perform global fit to radial velocities and magnitude measurements in 29 photometric bands of 287 Galactic, LMC, and SMC Cepheids, with P>10 days; assume Cepheid light curves and radial velocities are fully characterized by distance, reddening, and time-dependent radius and temperature variations.  Only 4-6 parameters per Cepheid, rms light and velocity curve of 0.05 mag and 3.5 km/s.  Model derives the mean Cepheid spectral energy distribution and its derivative wrt T, which deviate from a BB in agreement with metal-line and molecular opacity effects.  Determine a mean reddening law towards the Cepheids in our sample, which is not consistent with standard assumptions in the optical or NIR.  Based on stellar atmosphere models predict the biases in distance, reddening, and T determinations due to the metallicity and quantify the signature expected in the fit residuals.  Observed residuals as a function of wavelength show clear differences between the individual galaxies, which are compatible with these predictions.  Find metal-poor Cepheids appear hotter.  Provide a framework for optimally selecting filters that yield the smallest overall errors in Cepheid parameter determinations.  Make templates publicly available.


* see the accompanying video!


1112.3071
Observational evidence of quasar feedback quenching star formation at high redshift
Cano-Diaz, Maiolino, Marconi, Netzer, Shemmer, Cresci


Quasar feedback regulate SF: first observational evidence in the luminous quasar at z=2.4.  The OIII emission line reveals a massive outflow on scales of several kpc; the detection of narrow Halpha emission reveals star formation in the quasar host galaxy with 100 Msun/yr.  The SF is not distributed univormly; it is strongly suppressed in the region with the highest outflow velocity and highest velocity dispersion. Result indicates that in thie region SF is strongly quenched by the quasar outflow, which is cleaning the galaxy disk of its molecular gas.  


1112.3100
3D spherical analysis of BAO
Rassat, Refregier


Spherical Fourier-Bessel (SFB) decomposition is a natural basis for the analysis of fields in large surveys over radial and angular coverage.  Present a new way to analyse BASs by studying the BAO wiggles from the SFB power spectrum.  Ignoring evolution in the deep survey limit, the SFB power spectrum is purely radial and reduces to the Cartesian Fourier power spectrum.  In the thin shell limit, all thei nformation is contained in the tangential modles described by the 3d spherical harmonic power spectrum.  Find BAOs radialize more erapidly than the full SFB power spectrum [?].  Results suggest that the first peak of the BAOs in SFB space can be measured as radial out to l~10 for all-sky surveys with the same depth as SDSS or 2dF, and out to l~70 for an all-sky stage IV survey.  


1112.3108
On the measurement of cosmological parameters
Croft, Dailey


Historical measurements (1990-2010) of cosmological parameters.  Lesson: blind survey necessary.


1112.3116
Surface mass density of the Einasto family of DM haloes: are they Sersic-like?
Dhar, Williams


Einasto-model 3 parameter models are better able to produce fits to the 3d spatial density profiles than two-parameter models like NFW and Moore+ profiles.  Models of projected 2d Einasto profile that fits from 0 to 3x~5x r200 for a wide range of shape parameter alpha.  This model can thus be used in WL and SL fits of galaxies and clusters whose total spatial 3d density distributions are believed to be Einasto-like.  Further, given the dependence of the model on the 3d parameters, one can reliably estimate structural parameters of the spatial 3d density from the 2d observations.  Consider a Sersic-like parameterization of the above family of projected Einasto profiles, observe that fits with a Sersic profile are sensitive to whether one fits the projected density in linear scale of logarithmic scale and yield widely varying results.  Structural parameters of Einasto-like systems, inferred from fits with a sersic profiles, should be used with caution.


1112.3120
Surface Brightness and intrinsic luminosity of ellpticals
Dhar, Williams


For a sample of 23 ellipticals with MV > -24, models indicate that i) the central component is more concentrated than the outer component, and ii) the central component of 'core' galaxies is much more luminous, extended and concentrated than that of 'cuspy' galaxies, with their near exponential central profiles indicating disk-like systems whose existence must be verified spectroscopically.  Show that the existence, amount, radial extent and sign of mass deficits disagree substantially in the literature, both for a given galaxy and on an average over a sample.  SMBH binaries are unlikely to be the sole mechanism for producing the large 'cores'.  The outer component of the SB profiles of massive galaxies has 5<n<8 could imply 9) a common feature of collisionless systems, and ii) that galaxies with such n for their outer component are DM dominated.


1112.3122
On the initial shear field of the cosmic web
Rossi


* I don't know what he's talking about.


1112.3136
Sunlight refraction in the mesosphere of Venus during the transit on June 8th, 2004
Tanga et al


The spatially resolved data provide measurement of the aureole flux as a function of the planetocentric latitude along the limb.  A new differential refraction model of solar disk through the upper atmosphere allows us to relate the variable photometry to the latitudinal dependency of scale-height with temperature in the South polar region, as well as the latitudinal variation of the cloud-top layer altitude.  


1112.3143
Seeing in the dark -- II. Cosmic shear in the SDSS
Huff, Eifler, Hirata, Manelbaum, Schlegel, Seljak


Measure cosmic shear using coadded SDSS imaging in 168 sq. deg. of equatorial region, with r<23.5 and i<22.5, a source number density of 2.2 galaxies per square arcminute and median redshift of 0.52.  Paper I describe coadd generation that intended to minimise systematic errors due to coherent PSF anisotropies.  Present measurements of cosmic shear out to angular separation of 2 degrees, along with systematics test that demonstrate that the results are dominated by statistical rather than systematic errors.  Assuming a WMAP7 cosmological model and allowing only the amplitude of matter fluctuations to vary, find a best-fit value of sigma8=0.636 pm 0.1x with systematic errors.  Assuming a flat LCDM model, combined constraints with WMAP7 are sigma8=0.78 and omega_m h^2 = 0.13.  The 2 sigma error ranges are ~15 % smaller than WMAP7 alone.  Aside from intrinsic value of such cosmo constraints from the growth of structure, identify lessons for upcoming surveys that may face similar issues when combining multi-epoch data to measure cosmic shear.


1112.3264
A gas cloud on its way towards the SMBH in the galactic center
Gillessen, Genzel, Fritz, Quataert, ... et al


Report the presence of a dense gas cloud approximately 3 M_earth falling into the accretion zone of Sgr A*.  Cloud's orbit highly eccentric, innermost raidus of approach 3100x Schwartzchild radius that will be reached in 2013.  In the past 3 years, the cloud has begun to disrupt; observation of the next few years will probe the properties of the accretion flow and the feeding processes of the SMBH.  The keV X-ray emission of Sgr A* may brighten significantly when the cloud reaches pericenter.  There may also be a giant radiation flare several years from now if the cloud breaks up and its fragments feed gas into the central accretion zone.


1112.3300
Evolution of the stellar mass-metallicity relation since z=0.75
Moustakas, Zaritsky, Brown, Cool, Dey, Eisenstein, Gonzalez, Jannuzi, Jones, Kochanek, Murray, Wild


Find: at fixed stellar mass at z~0.7, galaxies have just 30-60% of the metal content of galaxies at the present epoch.  No statistically significant evidence that the M-Z relation evolves in a mass-dependent way for M=1e9.9-1e11 Msun SF galaxies.  This for thie range of redshifts and stellar masses, the M-Z relation simply shifts toward lower metallicity with increasing redshift without changing its shape.

Day 158

Wednesday.  Hope to get some good work done today.


1112.2698
Spectrosphotometric libraries, revised photonic passbands and zero-points for UBVRI, Hipparcos and Tycho photometry
Bessell, Murphy


Improved photonic passbands for UBVRI, compare with zero-points of SAAO UBVRI, homogenized UBV system and Walraven VB system.  Adjusted flux levels of stars in the spectrophotmetric libraries for the synthetic Hp magnitudes matched the precise Hipparcos catalog value.


1112.2701
Simulating the cooling flow of cool-core clusters
Li, Bryan


AMR simulations of a cool core cluster, resolving the flow from Mpc scales down to pc scales.  No AGN heating yet, but look at flow to understand how gas gets to the SMBH at the center of the cluster.  Cooling catastrophe only in the central 10-100 pc of the cluster.  Outside, the temperature is flat, flow is smooth, no local cooling instabilities, as with observations.  Cooling produces a thin accretion disk.  Cooled gas grows rapidly until the presumed AGN turn-on happens--like a thermostat.  Outcome is sensitive to resolution.


1112.2706
The baryon cencus in ta multiphase intergaalctic medium: one-third of the baryons are still missing
Shull, Smith, Danforth


Although galaxies and clusters contain 10% of the baryons, many more reside in the photoionized Lyman-alpha forest and shocked-heated warm-hot intergalactic medium (WHIM) at T=1e5K to 1e7K.  Low T WIM traced by O VI absorption lines, broad Ly-a absorbers (BLAs) and EUV/X-ray absorption lines from Ne VIII, O VII, and O VIII.  Improve the O VI baryon and metal transport in a density-temperature structured medium.  Statistically, their product correlates with column density.  Try lots of things.  Find substantial baryon fractions in the photoionized Lya formest at 28%, WHIM at 25%, and collapsed phase 18% in galaxies, groups, clusters, and circumgalactic gas.  Baryon shortfall is 29%, which may be detected in X-ray absorbers from hotter WHIM or weaker Lya and O VI absorbers.  


1112. 2710
Pair-instability SNe at the epoch of reionization
Pan, Kasen, Loeb


Model the light curves and spectra of pair-instability SNe over a range of masses and envelope structures.  At redshifts of reionization z>=6, calculate the rates and detectability of pair-instability and core collapse SNe, and show that with the JWST, it is possible to determine the contribution of Pop III and Pop II stars toward reionization by constraining the stellar initial mass function at that epoch using these SNe.  Also find rates of Types Ia SNe, and show that they are not rare during reionization, and can be used to probe the mass function at 4-8 Msun. If budget of ionizing photos was dominated by contributions from top-heavy Pop III stars, predict that the bright end of the galaxy luminosity function will be contaminated by pair-instability SNe.  


1112.2712
What shapes the galaxy mass function?  Exploring the roles of SN-driven winds and AGN
Bower, Benson, Crain


Observed stellar mass function (SMF) is very different to the halo mass function predicted by LCDM, and is widely accepted that this is due to energy feedback from SNe and BHs; but the strength and form of this feedback is not understood.  Use GALFORM to study how strength and the halo mass dependence of feedback affects the SF.  Focus on "expulsion" models in which the wind mass loading, beta, is proportional to 1/vdisk^n, n={0,1,2}, and contrast these models wit hthe successful Bower+ 2008 model.  Code explicitly accounts for the recapture of expelled gas as the system's halo mass increases.  Find: model with modest wind speed but high mass loading matches the flat portion of the SMF.  With AGN feedback, model provides a good description of the observed SMF above 1e9 Msun/h.  In the expulsion models, the brightest galaxies are assembled more recently than in Bower+2008, and sSFR of galaxies decrease strongly.  The Expulsion models also tend to have a comic SF density that is dominated by lower mass galaxies at z=1~3, and dominated high mass galaxies at low z.  


1112.2726
The growth of the stellar seeds of SMBH
Johnson, Whalen, Fryer, Li


Maximum masses the first stars can attain by accreting primordial gas is M*~1e3 Msun * (some function), however, at higher central infall rates, the lifetime of the star instead limits its final mass to >1e6 Msun.  Furthermore, the spherical accretion rates at which the star can grow, its ionizing radiation is confined deep within the protogalaxy, so the evolution of the star is decoupled from that of its host galaxy.  Lya emission from the surrounding H II region is trapped in these heavy accretion flows and likely reprocessed into strong Balmer series emission, which may be observable by JWST.  This, along with the He II 1640 A and continuum emission, are likely to be the key observational signatures of the progenitors of SMBH at high z.  


1112.2740
Do nuclear star clusters and BHs follow the same host-galaxy correlations?
Erwin, Gadotti


Strong correlation between nuclear star clusters (NSCs) and their host galaxies--not to the SMBH mass, but rather the stellar mass of the total stellar mass of the galaxies.  The M_nsc/Mstar,tot ratio is an order of magnitude smaller than M_bh/Mstar,bulge of SMBHs.   Galaxies with Hubble types earlier than Sbc appear to host systematically more massive NSCs than do types Sc and later.


1112.2752
The effects of baryon physics, BHs and AGN feedback on the mass distribution in clusters of galaixes
Martizzi, Teyssier, Moor, Wentz


Simulations find usual effects of overcooling and adiabatic contraction, but find very different results when implementing SMBHs and AGN feedback.  Star formation is strongly quenched, and much less cold gas is available for SF at low redshifts.  At redshift z=0 find a flat density core of radius 10 kpc in both the dark and stellar matter density profiles.  Speculate core formation mechanisms: can be produced through the coupling of different processes: (i) dynamical friction from the decay of BH orbits during galaxy mergers, (ii) AGN driven gas outflows producing fluctuations of the gravitational potential causing the removal of collisionless matter from the central region of the cluster, (iii) adiabatic expansion in response to the slow expulsion of gas from the central region of the cluster during the quiescent mode of AGN activity.  


1112.2764
The compositions of KBOs
Brown


A review of KBO surface composition.


1112.2772
The stagnation of contemporary stellar astronomy
Skoda


Nuclear fusion in stellar cores, exchange of mass in interacting binaries, models of stellar evolution towards WDs or NSs.  Despite its importance, it seems to be losing attention from the astronomical community.  Extra-galactic research and cosmology has taken over.  Analyse main obstacles lowering the efficiency of research in contemporary stellar astronomy.  


1112.2944
A comporehensive GALEX UV catalog of star clusters in M31 and a study of the young clusters
Kang, Rey, Bianchi, Lee, Kim, Sohn


Catalog of 700 confirmed star clusters in the M31 field compiled from 3 major catalogs.  Photometry in 16 passbands ranging from FUV to NIR as well as ancillary information such as reddening, metallicity, and radial velocities.  Ages and masses of star clusters derived  from multi-band photometry SED; UV photometry enables more accurate age estimation of young clusters.  182 of them < 1Gyr old.  Good agreement with previous literature.  Mean age and mass of young clusters are 300 Myr old and weigh 1e4 Msun.  The compiled [Fe/H] values of young clusters included in the catalog are systematically lower than those from recent high-quality spectroscopic data and the SED fitting result.  Confirm that most of the young cluster kinematics show systematic rotation around the minor axis and association with the thin disk of M31.  The young clusters distribution exhibits a distinct peak in the M31 disk around 10-12 kpc from the center and follow a spatial distribution similar to other tracers of disk structure such as OB stars, UV SF regions, and dust.  Some young clusters also show concentration around the ring splitting regions found in the southern part of the M31 disk and most of them have systematically younger (<100 Myr) ages.


1112.3004
Time in the 10,000-year clock
Hillis, Seaman, Allen, Giorgini


Long Now Foundation: building a mechanical clock that is designed to keep time for the next 10,000 years; maintains the long-term accuracy by synchronizing to the Sun.  Keeps track of 5 different types of time: (i) Pendulum Time: generated from the mechanical pendulum and adjusted according to the equation of time to produce: (ii) Uncorrected Solar Time: which in turn mechanically corrected by the Sun to create (iii) Corrected Solar Time.  (iv) Displayed Solar Time: used to compute various time indicators to be displayed, including the positions of the Sun, and Gregorian calendar date.  (v) Orrery Time: better approximation of dynamical time, used to compute positions of the Moon, planets and stars and the phase of the Moon.  Describe in particular how it reconciles the approximate Dynamical Time generated by its mechanical pendulum with the unpredictable rotation of the Earth.


1112.3006
The impact of assuming flatness in the determination of neutrino properties from cosmological data
Smith, Archidiacono, Cooray, De Bernardis, Melchiorri, Smidt


Find negative correlation between curvature and N_eff.  Even if Omega_k is allowed to vary, N_eff=3 is disfavored at 95% confidence.  Correlation between neutrino mass and curvature is much stronger, shifts upper limit from Sum m_nu < 0.446 eV to <0.948 eV.  The impact of assuming flatness in neutrino cosmology is significant and an essential consideration in future experiments.