Wednesday.
1211.2802
The impact of galaxy harassment on the globular cluster systems of early-type cluster dwarf galaxies
Smith et al
Find: dynamical behaviour of globular cluster systems (GCSs) is strongly influcenced yb the fraction of bound dark matter f_DM remaining in the galaxy. Only when f_DM falls to ~15% do stars and GCs begin to be stripped. ...
1211.2805
The explosion energy of early stellar populations: the Fe-peak element ratios in low metallicity damped Lyman-alpha systems
Cooke ... Steidel, et al
The relative abundances of Fe-peak elements (Ti-Zn) at the lowest metallicities are intimately linked to the physics of core-collpase SNe explosions. With a sample of 25 very metal-poor damped Ly-a systems, investigate the trends of the Fe-peak element ratios with metallicity. For the 9 of the 25 DLAs, a direct measurement (or upper limit) of one or more of the Ti,Cr,Co, Ni, Zn/Fe abundance ratios could be determined from detected absorption lines. For the remaining systems, devise a new form of spectral stacking to estimate the typical Fe-peak element ratios of the DLA population in this metallicity regime. Compare data to analogous measurements in metal-poor stars of the Galactic halo and to detailed calculations of explosive nucleosynthesis in metal-free stars. Conclude: most of the DLAs in this sample were enriched by stars that release an energy of <3e51 erg when they exploded as core-collpase supernovae. Find one DLA that appears to be modestly supersolar in Ni/Fe, and tentatively suggest that this system may have been enriched by hypernovae. Conclude by discussing the exciting prospect of measuring Fe-peak element ratios in damped Lyman-alpha systems with Fe/H<1/1000 of solar when 30-m class telescopes become available. Only then will we be able to pin down the energy that was release by the supernovae of the first stars.
1211.2816
Revisiting the scaling relations of black hole masses and host galaxy properties
McConnell, Ma
72 samples of BH and host galaxies. Scaling between sigma, L, and Mbulge. Bin into early and late-type galaxies. Power law fit with slope 5 for both, but intercept different: for early-type galaxies, find a significantly higher intercept for galaxies with central core profiles than for those with central power-law profiles. ...
121.2821
Reionization on large scales I: a parametric model constructed from radiation-Hydrodynamics simulations
Battaglia, Trac, Cen, Loeb
New method for modeling inhomogeneous cosmic reionization on large scales. High-res radiation-hydro sims. Reionizaton-redshift fields are highly correlated on large scales (>1Mpc/h). ...
1211.2822
Reionization on large scales II: detecting patchy reionization through cross correlation of the cosmic microwave background
Natarajan, Battaglia, Trac, Pen, Loeb
Effect of patchy reionizaton on the CMB temperature. An aniostropic optical depth tau alters the TT power spectrum on small scales (l>2000). Make use of the correlation between matter density and the reionization redshift fields to construct full sky maps of tau(theta). Patchy reionization transfers CMB power from large scales to small scales, resulting in a non-zero cross correlation between large and small angular scales. Also include CMB lensing, kSZ and tSZ terms, as well as IR and point source background, and show that patchy reionization may be detected in the low frequency channels, particularly for extended reionization histories. If frequency dependent secondaries can be minimized by a multi-frequency analysis, show that even small degrees of patchiness can be detected at high significance.
1211.2825
A physical model for the 0<z<8 redshift evolution of the galaxy UV luminosity and stellar mass functions
Tacchella, Trenti, Carollo
Basic model to understand the z evolution of UV luminosity and stellar mass functions of Lyman break galaxies. Minimal approach: L and M* related to its DM halo assembly and gas infall rate---secular SF activity sustained by steady gas accretion. Model calibrated by constructing a galaxy luminosity versus halo mass relation at z=4 via abundance matching; after calibration, model naturally fits the z=4 stellar mass function. Correctly predicts the evolution of both luminosity and stellar mass functions over 13 billion years, from z=0 to z=8. SF from steady gas accretion is the dominant contribution to the galaxy luminosity at all redshifts, but the initial burst of SF contributes significantly to the stellar mass assembly and evolution of the stellar mass function. While the details of SFE and feedback are hidden within the calibrated luminosity versus halo mass relation, our study highlights that the primary driver of galaxy evolution across cosmic time is the build-up of DM halos, without the need to invoke a redshift dependent efficiency in converting gas into stars.
1211.2915
Visualization of structures and cosmic flows in the local universe
Pomarede, et al
As the title says. MW motion: expulsion from the Local Void, the infall toward the Virgo Cluster, and the bulk flow of the historic Local Supercluster toward the Great Attractor, visualized.
1211.3105
Confirmation of the z~10 candidate UDFj-39546284 using deeper WFC3/IR+ACS+IRAC Observations over the HUDF09/XDF
Bouwens, Oesch, .. Smit, .. Franx, van Dokkum, et al
Confirmation that the z~10 candidate is indeed a source (not a spurious detection). [Still no spectra, but this will be probably hard to do.]
1211.2802
The impact of galaxy harassment on the globular cluster systems of early-type cluster dwarf galaxies
Smith et al
Find: dynamical behaviour of globular cluster systems (GCSs) is strongly influcenced yb the fraction of bound dark matter f_DM remaining in the galaxy. Only when f_DM falls to ~15% do stars and GCs begin to be stripped. ...
1211.2805
The explosion energy of early stellar populations: the Fe-peak element ratios in low metallicity damped Lyman-alpha systems
Cooke ... Steidel, et al
The relative abundances of Fe-peak elements (Ti-Zn) at the lowest metallicities are intimately linked to the physics of core-collpase SNe explosions. With a sample of 25 very metal-poor damped Ly-a systems, investigate the trends of the Fe-peak element ratios with metallicity. For the 9 of the 25 DLAs, a direct measurement (or upper limit) of one or more of the Ti,Cr,Co, Ni, Zn/Fe abundance ratios could be determined from detected absorption lines. For the remaining systems, devise a new form of spectral stacking to estimate the typical Fe-peak element ratios of the DLA population in this metallicity regime. Compare data to analogous measurements in metal-poor stars of the Galactic halo and to detailed calculations of explosive nucleosynthesis in metal-free stars. Conclude: most of the DLAs in this sample were enriched by stars that release an energy of <3e51 erg when they exploded as core-collpase supernovae. Find one DLA that appears to be modestly supersolar in Ni/Fe, and tentatively suggest that this system may have been enriched by hypernovae. Conclude by discussing the exciting prospect of measuring Fe-peak element ratios in damped Lyman-alpha systems with Fe/H<1/1000 of solar when 30-m class telescopes become available. Only then will we be able to pin down the energy that was release by the supernovae of the first stars.
1211.2816
Revisiting the scaling relations of black hole masses and host galaxy properties
McConnell, Ma
72 samples of BH and host galaxies. Scaling between sigma, L, and Mbulge. Bin into early and late-type galaxies. Power law fit with slope 5 for both, but intercept different: for early-type galaxies, find a significantly higher intercept for galaxies with central core profiles than for those with central power-law profiles. ...
121.2821
Reionization on large scales I: a parametric model constructed from radiation-Hydrodynamics simulations
Battaglia, Trac, Cen, Loeb
New method for modeling inhomogeneous cosmic reionization on large scales. High-res radiation-hydro sims. Reionizaton-redshift fields are highly correlated on large scales (>1Mpc/h). ...
1211.2822
Reionization on large scales II: detecting patchy reionization through cross correlation of the cosmic microwave background
Natarajan, Battaglia, Trac, Pen, Loeb
Effect of patchy reionizaton on the CMB temperature. An aniostropic optical depth tau alters the TT power spectrum on small scales (l>2000). Make use of the correlation between matter density and the reionization redshift fields to construct full sky maps of tau(theta). Patchy reionization transfers CMB power from large scales to small scales, resulting in a non-zero cross correlation between large and small angular scales. Also include CMB lensing, kSZ and tSZ terms, as well as IR and point source background, and show that patchy reionization may be detected in the low frequency channels, particularly for extended reionization histories. If frequency dependent secondaries can be minimized by a multi-frequency analysis, show that even small degrees of patchiness can be detected at high significance.
1211.2825
A physical model for the 0<z<8 redshift evolution of the galaxy UV luminosity and stellar mass functions
Tacchella, Trenti, Carollo
Basic model to understand the z evolution of UV luminosity and stellar mass functions of Lyman break galaxies. Minimal approach: L and M* related to its DM halo assembly and gas infall rate---secular SF activity sustained by steady gas accretion. Model calibrated by constructing a galaxy luminosity versus halo mass relation at z=4 via abundance matching; after calibration, model naturally fits the z=4 stellar mass function. Correctly predicts the evolution of both luminosity and stellar mass functions over 13 billion years, from z=0 to z=8. SF from steady gas accretion is the dominant contribution to the galaxy luminosity at all redshifts, but the initial burst of SF contributes significantly to the stellar mass assembly and evolution of the stellar mass function. While the details of SFE and feedback are hidden within the calibrated luminosity versus halo mass relation, our study highlights that the primary driver of galaxy evolution across cosmic time is the build-up of DM halos, without the need to invoke a redshift dependent efficiency in converting gas into stars.
1211.2915
Visualization of structures and cosmic flows in the local universe
Pomarede, et al
As the title says. MW motion: expulsion from the Local Void, the infall toward the Virgo Cluster, and the bulk flow of the historic Local Supercluster toward the Great Attractor, visualized.
1211.3105
Confirmation of the z~10 candidate UDFj-39546284 using deeper WFC3/IR+ACS+IRAC Observations over the HUDF09/XDF
Bouwens, Oesch, .. Smit, .. Franx, van Dokkum, et al
Confirmation that the z~10 candidate is indeed a source (not a spurious detection). [Still no spectra, but this will be probably hard to do.]
No comments:
Post a Comment