The Atacama Cosmology Telescope (ACT) is a six-meter telescope located at an altitude of 5190 meters (17,028 ft) on Cerro Toco in the Atacama Desert in Chile. ACT was built to study the Cosmic Microwave Background (CMB) by taking surveys of the sky at microwave wavelengths.  Three generations of cameras have been used with ACT, all relying on transition-edge-sensor (TES) bolometers, time-devision multiplexing (TDM) superconducting quantum interference devices (SQUIDs), and silicon lenses. The final camera, Advanced ACTPol (AdvACT) is being deployed at the site. AdvACT will map about half the sky in five frequency bands, from 28 to 230 GHz. It will map primary and secondary CMB anisotropies in intensity and polarization at a resolution of a few arcminutes, and will enable precision cosmological constraints as well as a wide array of cross-correlation science to probe the expansion history of the universe and the growth of large scale structure.

My work for ACT has involved a mix of device testing, remote observing, and data analysis. Using our lab’s dilution refrigerator and Multi-Channel Electronics (MCE) I have screened SQUID multiplexing chips to be used in our TDM readout architecture. I also analyze the maps that the ACT collaboration produces, working to extract thermal and kinematic Sunyaev-Zel’dovich signals from our images of the CMB (F. De Bernardis, S. Aiola, E. M. Vavagiakis, N. Battaglia, M. D. Niemack et al., Detection of the pairwise kinematic Sunyaev-Zel’dovich effect with BOSS DR11 and the Atacama Cosmology Telescope, JCAP 2017). Finally, I work as a remote observer, taking 24-hour shifts of control over the telescope and coordinating with Team Toco down at the site.


Screening a MUX board inside our dilution refrigerator at Cornell

Recent publications: 

M. Hilton, M. Hasselfield, C. Sifon, N. Battaglia, et al. (including E. M. Vavagiakis), 2018. “The Atacama Cosmology Telescope: The Two-Season ACTPol Sunyaev-Zel’Dovich Effect Selected Cluster Catalog,” The Astrophysical Journal Supplement Series, arXiv:1709.05600.

B. D. Sherwin, A. van Engelen, N. Sehgal, M. Madhavacheril et al. (including E. M. Vavagiakis), 2016. “The Atacama Cosmology Telescope: Two-Season ACTPol Lensing Power Spectrum,” Physical Review D 95, 123529 arXiv:1611.09753.

F. De Bernardis, S. Aiola, E. M. Vavagiakis, N. Battaglia, M. D. Niemack et al. 2017. “Detection of the pairwise kinematic Sunyaev-Zel’dovich effect with BOSS DR11 and the Atacama Cosmology Telescope,” Journal of Cosmology and Astroparticle Physics 03, 008, arXiv:1607.02139.

Y. Li, S. Choi, S. P. Ho, et al. (including E. M. Vavagiakis), 2016. “Assembly and integration process of the first high density detector array for the Atacama Cosmology Telescope,” Proc. SPIE 9914:991435.

F. De Bernardis, J. R. Stevens, M. Hasselfield, et al. (including E. M. Vavagiakis), 2016. “Survey strategy optimization for the Atacama Cosmology Telescope,” Proc. SPIE 9910:991014, arXiv:1607.02120.

Learn more about ACT:

Atacama Cosmology Telescope Homepage

Advanced ACTPol

Advanced ACTPol Readout Electronics

kSZ and tSZ Signals in ACTPol Maps


The ACT Collaboration at our 2018 meeting.

Header Image Credit: Mark Devlin/University of Pennsylvania