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Sunyaev-Zel’dovich Observations Using Large-Format Millimeter Arrays


Czakon, Nicole Gisela (2013) Sunyaev-Zel’dovich Observations Using Large-Format Millimeter Arrays. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/SRVP-D536.


Galaxy clusters are the largest gravitationally bound objects in the observable universe, and they are formed from the largest perturbations of the primordial matter power spectrum. During initial cluster collapse, matter is accelerated to supersonic velocities, and the baryonic component is heated as it passes through accretion shocks. This process stabilizes when the pressure of the bound matter prevents further gravitational collapse. Galaxy clusters are useful cosmological probes, because their formation progressively freezes out at the epoch when dark energy begins to dominate the expansion and energy density of the universe. A diverse set of observables, from radio through X-ray wavelengths, are sourced from galaxy clusters, and this is useful for self-calibration. The distributions of these observables trace a cluster's dark matter halo, which represents more than 80% of the cluster's gravitational potential. One such observable is the Sunyaev-Zel'dovich effect (SZE), which results when the ionized intercluster medium blueshifts the cosmic microwave background via Compton scattering. Great technical advances in the last several decades have made regular observation of the SZE possible. Resolved SZE science, such as is explored in this analysis, has benefitted from the construction of large-format camera arrays consisting of highly sensitive millimeter-wave detectors, such as Bolocam. Bolocam is a submillimeter camera, sensitive to 140 GHz and 268 GHz radiation, located at one of the best observing sites in the world: the Caltech Submillimeter Observatory on Mauna Kea in Hawaii. Bolocam fielded 144 of the original spider web NTD bolometers used in an entire generation of ground-based, balloon-borne, and satellite-borne millimeter wave instrumention. Over approximately six years, our group at Caltech has developed a mature galaxy cluster observational program with Bolocam. This thesis describes the construction of the instrument's full cluster catalog: BOXSZ. Using this catalog, I have scaled the Bolocam SZE measurements with X-ray mass approximations in an effort to characterize the SZE signal as a viable mass probe for cosmology. This work has confirmed the SZE to be a low-scatter tracer of cluster mass. The analysis has also revealed how sensitive the SZE-mass scaling is to small biases in the adopted mass approximation. Future Bolocam analysis efforts are set on resolving these discrepancies by approximating cluster mass jointly with different observational probes.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Galaxy Clusters ; Large-Scale Structure Formation ; Bolocam ; Chandra ; Sunyaev-Zel'dovich Effect
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Golwala, Sunil
Group:Astronomy Department
Thesis Committee:
  • Golwala, Sunil (chair)
  • Benson, Andrew J.
  • Readhead, Anthony C. S.
  • Zmuidzinas, Jonas
Defense Date:17 May 2013
Funding AgencyGrant Number
National Science FoundationNSF/AST-0838261
Gordon and Betty Moore Foundation.UNSPECIFIED
NASA Graduate Student Research FellowshipUNSPECIFIED
Record Number:CaltechTHESIS:06052013-104216835
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7842
Deposited By: Nicole Czakon
Deposited On:01 Oct 2014 17:46
Last Modified:05 Nov 2021 22:48

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