1301.0830
Effect of measurement errors on predicted cosmological constraints from shear peak statistics with LSST
Bard et al
The statistics of peak counts in reconstructed shear maps contain information beyond the power spectrum, and can improve cosmological constraints from measurements of the power spectrum alone if systematic errors can be controlled. Study the effect of galaxy shape measurement errors on predicted cosmological constraints from the statistics of shear peak counts with LSST. Use the LSST image simulator in combination with cosmological N-body simulations to model realistic shear maps for different cosmological models. Include both galaxy shape noise and measurement errors on galaxy shapes. Find that the measurement errors considered have little impact on the constraining power of shear peak counts for LSST.
1301.0871
Updated catalog of 132,684 galaxy clusters and evolution of brightest cluster galaxies
Wen, Han
132k clusters in 0.05<z<0.8 of SDSS DR8. 52k have spectro-z from DR9. BCGs are more luminous in richer clusters and at higher z.
1301.0983
Growth diagnostics for dark energy models
Sampurnanand, Sen
Introduce a new set of parameters r_g, s_g involving the linear growth of matter perturbation that can be used to distinguish different DE models. For LCDM, these parameters take exact values (1,1) at all z, but other models follow different trajectories in the r,s phase plane. With nearly identical evolution of the linear density contrast, one can still produce distinguishable trajectories in the r,s phase plane. It is also possible to put stringent constraint in the r,s phase plane, ruling out many possible DE behaviors.
[*]1301.1037
The Atacama cosmology telescope: temperature and gravitational lensing power spectrum measurements from three seasons of data
Das et al
Present temperature power spectra of CMB from 3 seasons of ACT at 148 and 218 GHz, as well as the cross-frequency spectrum between the two channels. Detect and correct for contamination due to the Galactic cirrus in equatorial maps. Present results of a number of tests for possible systematic error and conclude that any effects are not significant compared to the statistical errors quoted. Cross-correlate ACT with SPT maps, show that they are consistent. Measurements of higher-order peaks in the CMB power spectrum provide an additional test of the LCDM model, and help constrain extensions beyond the standard model. The smaller angular scale power spectrum also provides constraining power on the SZ effects and extragalactic foregrounds. Also present a measurement of the CMB gravitational lensing convergence power spectrum at 4.6 sigma detection significance.
1301.1041
Shocks, cooling and the origin of star formation rates in spiral galaxies
Bonnell, Dobbs, Smith
SF originates in the large scale dynamics of a galaxy, but occurs on the small scale of an individual SF event. Present first numerical simulation to resolve the SF process on sub-parsec scales, while also following the dynamics of the ISM on galactic scales. In the model, the warm low density ISM gas [from where? within the galaxy, or outside?] flows into the spiral arms where orbit crowding produces the shock formation of dense clouds, held together temporarily by their external pressure. Cooling allows the gas to be compressed to sufficiently high densities that local regions collapse under their own gravity and form stars. The SFR follow a Schmidt-Kennicutt Sigma_SFR~Sigma_gas^1.4 type relation with the local surface density of gas while following a linear relation with the cold and dense gas. Cooling is the primary driver of SF and the SFR as it determines the amount of cold gas available for gravitational collapse. The SFR found in the simulations are offset to higher values relative to the extragalactic values, implying a constant reduction, such as from feedback or magnetic fields, is likely to be required. Intriguingly, it appears that a spiral or other convergent shock and the accompanying thermal instability can explain how SF is triggered, generate the physical conditions of molecular clouds and explain why SFR are tightly correlated to the gas properties of galaxies.
[*]1301.1056
Mission to the Trojan Asteroids: lessons learned during a JPL planetary science summer school mission design exercise
Diniega, et al
The 2013 Planetary science decadal survey identified a detailed investigation of the Trojan asteroids occupying Jupiter's L4 and L5 Lagrange points as a priority for future NASA missions. Observing these asteroids and measuring their physical characteristics and composition would aid in identification of their source and provide answers about their likely impact history and evolution, thus yielding information about the makeup and dynamics of the early Solar system. Present a conceptual design for a mission to the Jovian Trojan asteroids: "TASTER" (Trojan ASteroid Tour, Exploration, and Rendezvous) mission, that is consistent with the NASA New Frontiers candidate mission recommended by the Decadal Survey and the final result of the 2011 NASA-JPL Planetary science summer school. Proposed mission includes visits to two Trojans in the L4 population: a 500 km altitude fly-by of 1999 XS143, followed by a rendezvous with and detailed observations of 911 Agamemnon at orbital altitudes of 1000-100 km over a 12 mo. nominal science data capture period. Proposed instrument payload (wide/narrow angle cameras, visual and IR mapping spectrometer, neutron/gamma ray spectrometer) would provide unprecedented high-res, regional-to-global datasets for the target bodies, yielding fundamental information about the early history and evolution of the Solar system. Although the mission design was completed as a part of an academic exercise, this study serves as a useful starting point for future Trojan mission design studies. In particular, we identify and discuss key issues that can make large difference in the complex trade-offs required when designing a mission to the Trojan asteroids.
[*]1301.1217
Modeling color-dependent galaxy clustering in cosmological simulations
Masaki, Lin, Yoshida
Extend subhalo abundance matching (SHAM) to assign galaxy color to subhaloes. Separate a luminosity-binned subhalo sample into 2 groups by a secondary subhalo property which is presumed to be correlated with galaxy color. The 2 subsamples then represent red and blue galaxy populations. Explore the two models for the secondary property; subhalo assembly time and local DM density around each subhalo. The model predictions for the galaxy 2-pt correlation functions are compared with the recent results from the SDSS. Show that the observed color dependence of galaxy clustering can be reproduced well by this method applied to cosmological N-body simulations without baryonic components. Then compare the model predictions for the color-dependent galaxy-mass cross correlation functions with the results from gravitational lensing observations. The comparison allows distinction of models, and also the discuss what subhalo property should be used to assign color to subhalos accurately. Show that the extended abundance matching method using local DM density as a color proxy provides an accurate description of the galaxy population in the local universe.
1301.1228
New constraints on cosmic reionization from the 2012 Hubble Ultra Deep Field campaign
Robertson, ... Ellis, ... et al
To study cosmic reionization, one needs to identify and characterize the early sources of H-ionizing photons. The UDF12 campaign has acquired the deepest IR images of the WFC3 on Hubble, and systematically explored the galaxy population deep into the era when CMB data indicates reionization was underway. The UDF12 campaign thus provides the best constraints to date on the abundance, luminosity distribution, and spectral properties of early SF galaxies. Synthesize the new UDF12 results with the most recent constraints from CMB observations to infer z-dependent UV luminosity density, reionization histories, and e- scattering optical depth evolution consistent with the available data. Under reasonable assumptions about the escape fraction of hydrogen ionizing photons and the intergalactic medium clumping factor, find that to fully reionize the universe by z~6 the population of SF galaxies at z~7-9 likely must extend in luminosity below the UDF12 limits to absolute UV magnitudes of -13 or fainter. Low levels of SF extending to z~15-25, as suggested by the normal UV colors of z~7-8 galaxies and the smooth decline in abundance with z observed by UDF12 to z~10, are additionally likely required to reproduce the optical depth to e- scattering inferred from CMB observations.
1301.0952
TASI 2012 lectures on astrophyscial probes of dark matter
Profumo
Connection between how DM was produced in the early universe, and how this can be detected today; where does the WIMP miracle come from (is it really a miracle)? What brackets the mass range for thermal relics? Where does <sigma v> come from, and what does it mean? What is the difference between chemical and kinetic decoupling? WHy do some people think that DM cannot be lighter than 40 GeV? Why is \bar{b} b such a popular annihilation final state? Why is antimatter a good way to look for DM? Why should the CR positron fraction decline with energy, and why does it not? How does one calculate the flux of neutrinos from DM annihilation in a celestial body, and when is that flux independent of the DM pair-annihilation rate? How does DM produce photons? What You Always Wanted to Know About Dark Matter But Were Afraid to Ask!
The statistics of peak counts in reconstructed shear maps contain information beyond the power spectrum, and can improve cosmological constraints from measurements of the power spectrum alone if systematic errors can be controlled. Study the effect of galaxy shape measurement errors on predicted cosmological constraints from the statistics of shear peak counts with LSST. Use the LSST image simulator in combination with cosmological N-body simulations to model realistic shear maps for different cosmological models. Include both galaxy shape noise and measurement errors on galaxy shapes. Find that the measurement errors considered have little impact on the constraining power of shear peak counts for LSST.
1301.0871
Updated catalog of 132,684 galaxy clusters and evolution of brightest cluster galaxies
Wen, Han
132k clusters in 0.05<z<0.8 of SDSS DR8. 52k have spectro-z from DR9. BCGs are more luminous in richer clusters and at higher z.
1301.0983
Growth diagnostics for dark energy models
Sampurnanand, Sen
Introduce a new set of parameters r_g, s_g involving the linear growth of matter perturbation that can be used to distinguish different DE models. For LCDM, these parameters take exact values (1,1) at all z, but other models follow different trajectories in the r,s phase plane. With nearly identical evolution of the linear density contrast, one can still produce distinguishable trajectories in the r,s phase plane. It is also possible to put stringent constraint in the r,s phase plane, ruling out many possible DE behaviors.
[*]1301.1037
The Atacama cosmology telescope: temperature and gravitational lensing power spectrum measurements from three seasons of data
Das et al
Present temperature power spectra of CMB from 3 seasons of ACT at 148 and 218 GHz, as well as the cross-frequency spectrum between the two channels. Detect and correct for contamination due to the Galactic cirrus in equatorial maps. Present results of a number of tests for possible systematic error and conclude that any effects are not significant compared to the statistical errors quoted. Cross-correlate ACT with SPT maps, show that they are consistent. Measurements of higher-order peaks in the CMB power spectrum provide an additional test of the LCDM model, and help constrain extensions beyond the standard model. The smaller angular scale power spectrum also provides constraining power on the SZ effects and extragalactic foregrounds. Also present a measurement of the CMB gravitational lensing convergence power spectrum at 4.6 sigma detection significance.
1301.1041
Shocks, cooling and the origin of star formation rates in spiral galaxies
Bonnell, Dobbs, Smith
SF originates in the large scale dynamics of a galaxy, but occurs on the small scale of an individual SF event. Present first numerical simulation to resolve the SF process on sub-parsec scales, while also following the dynamics of the ISM on galactic scales. In the model, the warm low density ISM gas [from where? within the galaxy, or outside?] flows into the spiral arms where orbit crowding produces the shock formation of dense clouds, held together temporarily by their external pressure. Cooling allows the gas to be compressed to sufficiently high densities that local regions collapse under their own gravity and form stars. The SFR follow a Schmidt-Kennicutt Sigma_SFR~Sigma_gas^1.4 type relation with the local surface density of gas while following a linear relation with the cold and dense gas. Cooling is the primary driver of SF and the SFR as it determines the amount of cold gas available for gravitational collapse. The SFR found in the simulations are offset to higher values relative to the extragalactic values, implying a constant reduction, such as from feedback or magnetic fields, is likely to be required. Intriguingly, it appears that a spiral or other convergent shock and the accompanying thermal instability can explain how SF is triggered, generate the physical conditions of molecular clouds and explain why SFR are tightly correlated to the gas properties of galaxies.
[*]1301.1056
Mission to the Trojan Asteroids: lessons learned during a JPL planetary science summer school mission design exercise
Diniega, et al
The 2013 Planetary science decadal survey identified a detailed investigation of the Trojan asteroids occupying Jupiter's L4 and L5 Lagrange points as a priority for future NASA missions. Observing these asteroids and measuring their physical characteristics and composition would aid in identification of their source and provide answers about their likely impact history and evolution, thus yielding information about the makeup and dynamics of the early Solar system. Present a conceptual design for a mission to the Jovian Trojan asteroids: "TASTER" (Trojan ASteroid Tour, Exploration, and Rendezvous) mission, that is consistent with the NASA New Frontiers candidate mission recommended by the Decadal Survey and the final result of the 2011 NASA-JPL Planetary science summer school. Proposed mission includes visits to two Trojans in the L4 population: a 500 km altitude fly-by of 1999 XS143, followed by a rendezvous with and detailed observations of 911 Agamemnon at orbital altitudes of 1000-100 km over a 12 mo. nominal science data capture period. Proposed instrument payload (wide/narrow angle cameras, visual and IR mapping spectrometer, neutron/gamma ray spectrometer) would provide unprecedented high-res, regional-to-global datasets for the target bodies, yielding fundamental information about the early history and evolution of the Solar system. Although the mission design was completed as a part of an academic exercise, this study serves as a useful starting point for future Trojan mission design studies. In particular, we identify and discuss key issues that can make large difference in the complex trade-offs required when designing a mission to the Trojan asteroids.
[*]1301.1217
Modeling color-dependent galaxy clustering in cosmological simulations
Masaki, Lin, Yoshida
Extend subhalo abundance matching (SHAM) to assign galaxy color to subhaloes. Separate a luminosity-binned subhalo sample into 2 groups by a secondary subhalo property which is presumed to be correlated with galaxy color. The 2 subsamples then represent red and blue galaxy populations. Explore the two models for the secondary property; subhalo assembly time and local DM density around each subhalo. The model predictions for the galaxy 2-pt correlation functions are compared with the recent results from the SDSS. Show that the observed color dependence of galaxy clustering can be reproduced well by this method applied to cosmological N-body simulations without baryonic components. Then compare the model predictions for the color-dependent galaxy-mass cross correlation functions with the results from gravitational lensing observations. The comparison allows distinction of models, and also the discuss what subhalo property should be used to assign color to subhalos accurately. Show that the extended abundance matching method using local DM density as a color proxy provides an accurate description of the galaxy population in the local universe.
1301.1228
New constraints on cosmic reionization from the 2012 Hubble Ultra Deep Field campaign
Robertson, ... Ellis, ... et al
To study cosmic reionization, one needs to identify and characterize the early sources of H-ionizing photons. The UDF12 campaign has acquired the deepest IR images of the WFC3 on Hubble, and systematically explored the galaxy population deep into the era when CMB data indicates reionization was underway. The UDF12 campaign thus provides the best constraints to date on the abundance, luminosity distribution, and spectral properties of early SF galaxies. Synthesize the new UDF12 results with the most recent constraints from CMB observations to infer z-dependent UV luminosity density, reionization histories, and e- scattering optical depth evolution consistent with the available data. Under reasonable assumptions about the escape fraction of hydrogen ionizing photons and the intergalactic medium clumping factor, find that to fully reionize the universe by z~6 the population of SF galaxies at z~7-9 likely must extend in luminosity below the UDF12 limits to absolute UV magnitudes of -13 or fainter. Low levels of SF extending to z~15-25, as suggested by the normal UV colors of z~7-8 galaxies and the smooth decline in abundance with z observed by UDF12 to z~10, are additionally likely required to reproduce the optical depth to e- scattering inferred from CMB observations.
1301.0952
TASI 2012 lectures on astrophyscial probes of dark matter
Profumo
Connection between how DM was produced in the early universe, and how this can be detected today; where does the WIMP miracle come from (is it really a miracle)? What brackets the mass range for thermal relics? Where does <sigma v> come from, and what does it mean? What is the difference between chemical and kinetic decoupling? WHy do some people think that DM cannot be lighter than 40 GeV? Why is \bar{b} b such a popular annihilation final state? Why is antimatter a good way to look for DM? Why should the CR positron fraction decline with energy, and why does it not? How does one calculate the flux of neutrinos from DM annihilation in a celestial body, and when is that flux independent of the DM pair-annihilation rate? How does DM produce photons? What You Always Wanted to Know About Dark Matter But Were Afraid to Ask!
No comments:
Post a Comment