Category Archives: Uncategorized

Last week we submitted 2 new papers to the arxiv!  The first, led by K.G. Lee, summarizes the first release of CLAMATO data, including a redshift catalog of our sources, 437 reduced Keck spectra, Lyman-alpha forest pixel data, and the Wiener-filtered 3D map.  It also presents our visualizations, including a Youtube-360 version of the tomographic map, which can be used with a Google Cardboard or similar device for an immersive 3D experience.

The second, led by Alex Krolewski, presents the first detection of cosmic voids at z~2.3, the most distant detection of voids yet.  This paper applies the method developed by Casey Stark to the CLAMATO data and presents exploratory void profiles and the void radius function at z~2.3.

A new paper, led by Alex Krolewski (UC Berkeley) has been submitted to arXiv. This uses cosmological simulations to study how IGM tomography maps could be used to  to constrain alignments between galaxy spins or shapes with the underlying cosmic web at z~2.5.

K.G. Lee will be giving a talk on CLAMATO at the Astronomy on Tap event at Black Hammer Brewing in San Francisco, at 8pm on Tuesday Nov 1st. Drop by for beer and CLAMATO if you’re in the area!

We will presenting VR visualizations of CLAMATO Survey data at the Vision+Light: Extending the Senses outreach event in Berkeley. This will be at 5:30-8:30pm on Thursday and Friday, Oct 27-28, 2016, at Energy Biosciences Institute in UC Berkeley (intersection of Hearst and Oxford). Come experience our 3D IGM tomography map, as well as other awesome exhibits!

CLAMATO LMAP survey’s goal is to map the z ∼ 2.3 cosmic web with Lyα forest tomography using Keck-I/LRIS to collect data. This technique expands upon the HI Lyα forest analysis of IGM absorption that is traditionally carried out along relatively rare quasar lines-of-sight by targeting ubiquitous star-forming Lyman-Break galaxies (LBGs) and faint quasars at z ∼ 2 − 3 as background sources. One can then tomographically interpolate across the adjacent lines-of-sight to yield 3D maps of the IGM HI absorption, which is a non-linear tracer of the cosmic web in dark matter.

Due to the long (∼ 400 h−1 Mpc) path length in the Lyα forest probed by each background source, this technique allows the mapping of large volumes at z > 2. This project will allow the first characterization of galaxy environments at the given redshifts as well as studying extended voids and protoclusters. 

Area covered in the survey: 

The survey aims to make the first characterization of sheets and filaments of the high-redshift cosmic web. Additionally, it hopes to provide a measure of the local environmental density at the positions of individual galaxies with a  2.2 < z < 2.5 redshift.