Wine and Cheese Fall 2014: Difference between revisions

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The hydrogen Lyman-alpha forest is a long-established probe of large-scale structure at z>2, but is typically limited to 1D investigations along individual quasar sightlines.  However, by instead targeting LBGs as background sources, the transverse separation between sources is ~Mpc and it becomes possible to do a 3D 'tomographic' reconstruction of the intergalactic medium. I will describe pilot observations using this technique, which has produced the first map of 3D large-scale structure at z~2.3 within the COSMOS field. Comparisons with coeval galaxies and simulations indicate that our map is truly tracing large-scale structure. This motivates the CLAMATO survey, which will map out a volume of (100 Mpc/h)^3 at z~2.3 and allow us to search for galaxy protoclusters, study the effect of environment on galaxy evolution, and constrain cosmological parameters.
The hydrogen Lyman-alpha forest is a long-established probe of large-scale structure at z>2, but is typically limited to 1D investigations along individual quasar sightlines.  However, by instead targeting LBGs as background sources, the transverse separation between sources is ~Mpc and it becomes possible to do a 3D 'tomographic' reconstruction of the intergalactic medium. I will describe pilot observations using this technique, which has produced the first map of 3D large-scale structure at z~2.3 within the COSMOS field. Comparisons with coeval galaxies and simulations indicate that our map is truly tracing large-scale structure. This motivates the CLAMATO survey, which will map out a volume of (100 Mpc/h)^3 at z~2.3 and allow us to search for galaxy protoclusters, study the effect of environment on galaxy evolution, and constrain cosmological parameters.
== Peter Behroozi ==
== Peter Behroozi ==
'''Title''' <br>
'''Close Pairs: Observational Probes for how Halo Accretion Impacts Galaxy Star Formation''' <br>
Abstract
 
We present a simple observational method for selecting galaxies whose host dark matter haloes have had significantly higher-than-average accretion rates. The method relies on using close pairs of galaxies to preferentially identify major dark matter halo mergers. Applying the method to central L∗ galaxies in the Sloan Digital Sky Survey (SDSS) DR10, we find no evidence for enhanced average or median star formation accompanying as much as an 0.3 dex increase in average halo accretion rates. However, population subsamples do show enhancements. Most interestingly, star-forming L∗ galaxies show a double peak in star formation enhancements as a function of the distance to the close pair. The larger (factor of 2) enhancement occurs for close pairs within 30 kpc, and the smaller (factor of 40%) enhancement occurs for pairs separated by 100-200 kpc (i.e., just within the virial radius of the larger galaxy’s halo). We discuss implications for conditional abundance matching models; while galaxy quenchedness cannot depend only on halo mass and recent accretion, reproducing the full behaviour of star-forming galaxies requires more advanced models than currently exist.


= 15 Sept 2014 =
= 15 Sept 2014 =

Revision as of 22:39, 26 August 2014

Back to W&C Schedule

8 Sept 2014

K.G. Lee

The First z>2 Large-Scale Structure Map with Lyman-Alpha Forest Tomography from LBGs
The hydrogen Lyman-alpha forest is a long-established probe of large-scale structure at z>2, but is typically limited to 1D investigations along individual quasar sightlines. However, by instead targeting LBGs as background sources, the transverse separation between sources is ~Mpc and it becomes possible to do a 3D 'tomographic' reconstruction of the intergalactic medium. I will describe pilot observations using this technique, which has produced the first map of 3D large-scale structure at z~2.3 within the COSMOS field. Comparisons with coeval galaxies and simulations indicate that our map is truly tracing large-scale structure. This motivates the CLAMATO survey, which will map out a volume of (100 Mpc/h)^3 at z~2.3 and allow us to search for galaxy protoclusters, study the effect of environment on galaxy evolution, and constrain cosmological parameters.

Peter Behroozi

Close Pairs: Observational Probes for how Halo Accretion Impacts Galaxy Star Formation

We present a simple observational method for selecting galaxies whose host dark matter haloes have had significantly higher-than-average accretion rates. The method relies on using close pairs of galaxies to preferentially identify major dark matter halo mergers. Applying the method to central L∗ galaxies in the Sloan Digital Sky Survey (SDSS) DR10, we find no evidence for enhanced average or median star formation accompanying as much as an 0.3 dex increase in average halo accretion rates. However, population subsamples do show enhancements. Most interestingly, star-forming L∗ galaxies show a double peak in star formation enhancements as a function of the distance to the close pair. The larger (factor of 2) enhancement occurs for close pairs within 30 kpc, and the smaller (factor of 40%) enhancement occurs for pairs separated by 100-200 kpc (i.e., just within the virial radius of the larger galaxy’s halo). We discuss implications for conditional abundance matching models; while galaxy quenchedness cannot depend only on halo mass and recent accretion, reproducing the full behaviour of star-forming galaxies requires more advanced models than currently exist.

15 Sept 2014

Dheeraj Pasham

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Alex Mendez

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22 Sept 2014

Yacine Ali-Haïmoud

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Jim Green

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29 Sept 2014

Remco van den Bosch

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Omer Bromberg

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6 Oct 2014

Matthias Bartelmann

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Roseanne Cheng

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13 Oct 2014

Jeff Cummings

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20 Oct 2014

27 Oct 2014

3 Nov 2014

Chun Ly

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