Angela Burden Cosmology
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My work focuses on the development of algorithms that ensure we can make the most precise measurements of the expansion history of the Universe from the data we have available to us.
Specifically, I work with the Baryon Acoustic Oscillation (BAO) signal which is statistically apparent in the spatial distribution of galaxies measured over large volumes of space.
The BAO signal is used as a standard ruler to measure the cosmological distance-redshift relation. The signal was generated in the matter distribution when the Universe was very young (~300,000 yrs old). Over time the clarity of the signal has been degraded due to gravitationally induced flows of matter decoupled from the general Hubble expansion, and non-linear structure formation.
RECONSTRUCTION
The reconstruction technique uses information contained in the evolved galaxy overdensity field to estimate motions that decrease the linear BAO signal to noise. The motions are undone resulting in a sharper BAO signal and ultimately a more precise distance-redshift measurement.
I have implemented a reconstruction pipeline which has been used to reconstruct the BAO signal in several galaxy samples.
The reconstruction steps are outlined in the series of plots in the slide show to the left.
A thin slice through the DR12 (BOSS) survey near an edge. Galaxies are purple. The survey mask is quantified by a random catalogue in blue.
The contrast between randoms and galaxies gives us the overdensity.
The reconstruction increases the clarity of our BAO signal!
A thin slice through the DR12 (BOSS) survey near an edge. Galaxies are purple. The survey mask is quantified by a random catalogue in blue.