1202.0003
The relation between ejecta velocity, intrinsic color, and hist-galaxy mass for high-z type Ia SNe
Foley
Recently discovered a relation between SNIa ejecta velocity and intrinsic color at low-z that improves the distance precision of SNIa and reduces potential systematic biases related to dust reddening. Use SDSS-II and SNLS data and correct for the velocity-color relation to constrain high-z relation constraint. Measure eject velocities at maximum brightness for Ca H&K and Si II 6355 features from spectra. Find higher ejecta velocity tend to be intrinsically redder than lower ejecta velocity. Distribution of ejecta velocities for SNIa at low and high z similar, so current cosmo results should have little bias related to velocity-color relation. Find slight trend between ejecta velocity and host-galaxy mass (high-mass hosts have lower ejecta velocities).
1202.0005
COnstraints on neutrino mass and light degrees of freedom in extended cosmological parameters spaces
Joudaki
Combine WMAP7, SPT, HST, BAO from SDSS+2dFGRS, and Union2 (SNe), explore the extent to which the constraints on the effective number of neutrinos and sum of neutrino masses are affected by the ignorance of other cosmological parameters, including the curvature of the universe, running of the spectral index, primordial helium abundance, evolving late-time DE, and early DE. In a combined analysis of the effetive number of neutrinos and sum of neutrino masses, find 2 sigma evidence for additional light degrees of freedom. When evolving DE is allowed, and relaxing the inflation prior on the curvature and running, data is consistent with no extra relativistic species. Early DE cannot be more than 5% of the critical density (although it improves nu species = 3). The derived amplitude of sigma_8 agree closely with low-z cluster abundance measurements. Sum of neutrino masses robust to assumptions of the effective number of neutrinos, late-time DE, curvature, and running at 1.2 eV. Upper bound degrades to 2.0 eV when including early DE and primordial He abundance as additional free parameters. Even with maximal extension of parameter space, Planck alone can determine the existence of extra relativistic species at 4 sigma confidence and constrain the sum of neutrino masses to 0.2 eV.
1202.0007
Direct detection of dark matter debris flows
Kuhlen, Lisanti, Spergel
Tidal stripping: produces narrow, cold tidal streams, as well as more spatially extended "Debris flows" inthe form of shells, sheets, and plumes. In Via Lactea II sim, this incompletely phase-mixed material exhibits distinctive high-velocity behavior. Unlike tidal streams, which may not necessarily intersect the Earth's location, debris flow is spatially uniform at 8 kpc and thus guaranteed to be present in DM flux indicent on direct detection experiments. At earth-frame velocities greater than 450 km/s, debris flow comprises more than half of the DM at the Sun's location, and up to 80% at even higher velocities. Therefore, debris flow is most important for experiments that are particularly sensitive to the high velocity tale of the DM distribution, such as searches for light or inelastic DM or experiments with directional sensitivity. Show that debris flow yields a distinctive recoil energy spectrum and broadening of the distribution of incidence direction.
1202.0010
Gamma-ray-burst host galaxy surveys at z>4: probes of SFR and cosmic reionization
Trenti, Perna, Levesque, Shull, Stocke
1202.0007
Direct detection of dark matter debris flows
Kuhlen, Lisanti, Spergel
Tidal stripping: produces narrow, cold tidal streams, as well as more spatially extended "Debris flows" inthe form of shells, sheets, and plumes. In Via Lactea II sim, this incompletely phase-mixed material exhibits distinctive high-velocity behavior. Unlike tidal streams, which may not necessarily intersect the Earth's location, debris flow is spatially uniform at 8 kpc and thus guaranteed to be present in DM flux indicent on direct detection experiments. At earth-frame velocities greater than 450 km/s, debris flow comprises more than half of the DM at the Sun's location, and up to 80% at even higher velocities. Therefore, debris flow is most important for experiments that are particularly sensitive to the high velocity tale of the DM distribution, such as searches for light or inelastic DM or experiments with directional sensitivity. Show that debris flow yields a distinctive recoil energy spectrum and broadening of the distribution of incidence direction.
1202.0010
Gamma-ray-burst host galaxy surveys at z>4: probes of SFR and cosmic reionization
Trenti, Perna, Levesque, Shull, Stocke
Should detect SF in GRB hosts at z~5.
* This report is in disagreement with the other 2 recent papers about GRB hosts at high z: that the host galaxies are barely detected (let alone, SFR).
1202.0029
High spectral resolution measurement of the SZ effect null with Z-spec
Zemcov, ,Aguirre, ... et al
SZ null expected to be at 217 GHz, measured at 225.8 GHz in RX J1347.5-1145, a 3 sigma discrepancy. Evidence for modifications to the canonical thermal SZ effect shape. T_e = 17 keV from zero pt measurement alone. Peculiar velocity most probably at 450 pm 810 km/s.
1202.0041
The cosmic history of hot gas cooling and radio AGN activity in massive early-type galaxies
Danielson, Lehmer, Alexander, Brandt, Luo, Miller, Xue, Stott
393 ETGs of 0<z<1.2 in Chandra Deep Fields. Measure average X-ray properties of the ETG population. Stack X-ray with 158 passive ETGs over all redshift range, contribution from individually undetected AGNs expected to be negligible. 55 ETGs detected individually in X-ray, 12 have properties consistent with being passive hot-gas dominated systems (not dominated by AGN). Find little evolution of L_X/L_B luminosity ration, implying that some heating mechanism prevents the gas from cooling in these systems. Consider that feedback from radio-mode AGN activity could be responsible for heating the gas. Select AGNs in the ETG population. Radio observations constrain duty cycle history of AGN in the sample. Avg mechanical power from AGN activity is a factor of 1.5-2.5 times larger than average radiative cooling power from hot gas over the redshift range. The excess of inferred AGN mechanical power from these ETGs is consistent with that found in the local universe for similar types of galaxies.
Silk damping erase primordial fluctuations on this scale (50 Mpc^-2<k<1e4 Mpc^-2). Consistent treatment of primordial dissipation problem requires going to 2nd order in perturbation theory, while thermalization of these distorutions necessitates consideration of 2nd ordr in Compton scattering energy transfer. Give a full 2x2 treatment for creation and evolution of spectral distortions due ot the acoustic dissipation process, consistently including the effect of polarization and photon mixing in the free streaming regime. Show that 1/3 of thetotal energy stored in small scale temperature perturbations imprints observable spectral distortions, while the remaining 2/3 only raise the average CMB temperature, an effect that is unobservable. At high z dissipation is mainly mediated through the quadrupole anisotropies, while after recombination peculiar motions are most important. During recombination the damping of the higher multipoles is also significant. COmpute average distortion for several examples. THe cooling of baryonic matter practically compensates the heating from acoustic dissipation.
* i didn't get this one very well...
1202.0090
A 2% distance to z=0.35 by reconstructing BAO -- I: methods and application to the SDSS
Padmanabhan, Xu, Eisenstein, Scalzo, Cuesta, Mehta, Kazin
Apply BAO reconstruction. Validate on 160 LasDamas sims, show uncertainty reduced from 3% to 2%. Apply method to SDSS LRG DR7 sample, improve BAO feature significance from 3.3 to 4.2. Estimate relative distance scale. Distance error reduced by ~50%, equivalent to survey with 3 times the volume of SDSS.
1202.0091
A 2% distance to z=0.35 by reconstructing BAO -- II: fitting techniques
Xu, Padmanbhan, Eisenstein, Mehta, Cuesta
The techniques for above.
1202.0092
A 2% distance to z=0.35 by reconstructing BAO -- III: cosmological measurements and interpretation
Mehta, Cuesta, Xu, Eistenstein, Padmanabhan
Cosmological constraints from above, combined with WMAP7. Measurement of H0 = 69.8 pm 1.2, Omega_m =0.280 pm 0.014 for a flat universe; w=-0.92 pm 0.13. if curvature varies, universe is consistent with flat. Combine other BAO and SN data.
1202.0102
Dithering strategies and point-source photometry
Samsing, Kim
Photometry accuracy depends on the PSF, detector pixelization, and observing strategy (dithering). Distribution of photometric uncertainty for sources of fixed flux that fall in a field. Flux determination depends slightly on dithering strategy; position determination strongly dependent on dithering. Configuration of large pixels: uncertainty distributions can be non-Gaussian, RMS value dependent on dither strategy. COnfigurations with large pixels, pointings dithered by a fractional pixel do not always give minimal average uncertainties. If fractional dithering favored (pixels small), pointing accuracy of better than 0.15 pix required to maintain the advantage over random dithers.
* doesn't this then depend on the astrometry?
1202.0185
Cluster Lenses [review article]
Kneib, Natarajan
SL regime, WL regime. Study of lens, and lensed objects. Study the geometryr of the universe.
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