South Pole Telescope
Sub-Millimeter Galaxies

Science:

Half of the energy produced since recombination has been absorbed and reemitted by dust. This radiation, the cosmic infrared background (CIB), is produced primarily by dusty, star-forming galaxies (DSFGs) at z~1-3, with a tail extending beyond z>6. These objects were first identified in submillimeter-wavelength (submm) surveys of the extragalactic sky and found to be orders of magnitude more abundant in the early Universe than the present day. These studies upended our view of cosmic star formation, demonstrating that the bulk of star formation activity in the Universe could be taking place in DSFGs that were invisible in optical and ultraviolet surveys due to dust obscuration.

Recently, large-area millimeter/submillimeter surveys have become available and proven to be efficient for selecting rare (<0.1 per sq. deg.), gravitationally lensed DSFGs. Due to the strong gravitational lensing, these objects typically appear an order of magnitude more luminous than the bulk DSFG population, with a corresponding increase in their solid angle on the sky. This provides a spectacular reduction in the integration times required to detect lensed sources, makes weak spectral lines accessible, and magnifies the resolving power of our telescopes.

The South Pole Telescope (SPT) has systematically identified a large number of high-redshift strongly gravitationally lensed starburst galaxies in a 2500 square degree cosmological survey of the millimeter (mm) sky. These sources are selected by their extreme mm flux, which is largely independent of redshift and lensing configuration. The flux magnification provided by the gravitational lensing enabled us to perform a spectroscopic redshift survey with the recently commissioned Atacama Large Millimeter Array (ALMA). We targeted 26 SPT sources and obtained redshifts via molecular carbon monoxide (CO) lines. With a 90% detection rate, our ALMA+SPT CO redshift survey is the most complete DSFG survey to date. We determine that roughly 35% of these sources lie at z>4, indicating the fraction of dusty starburst galaxies at high-redshift is far higher than previously thought. Two sources are at z=5.7, placing them among the highest redshift starbursts known, and demonstrating that large reservoirs of molecular gas and dust can be present in massive galaxies near the end of the epoch of cosmic reionization. These sources were additionally targeted with high resolution imaging with ALMA, unambiguously demonstrating them to be strongly gravitationally lensed by foreground structure, and enabling us to make detailed and robust lens models.

The SPT has identified the brightest high-redshift sources in the extragalactic sky visible from ALMA, and assembled a sample of ~100 strongly lensed, dusty, starburst galaxies. We are undertaking a comprehensive and systematic followup campaign to use these "cosmic magnifying glasses'' to study the infrared background in unprecedented detail, inform the condition of the interstellar medium in starburst galaxies at high redshift, and place limits on dark matter substructure.

Papers:

ApJ discovery and catalog paper here: Vieira et al. 2010 ADS
You can get the catalog and source counts from the first 100 square degrees here

ApJ paper presenting APEX submm imaging, SED fitting, and photometric redshift method here: Greve et al. 2012 ADS

Nature paper reporting the first ALMA blind redshift search and strong lensing: Vieira et al. 2013 ADS

ApJ paper reporting ALMA spectra and spectroscopic redshift distribution from carbon monoxide: Weiss et al. 2013 ADS

ApJ paper detailing the ALMA imaging and lens modelling: Hezaveh et al. 2013 ADS

MNRAS paper detailing CO(1-0) with ATCA: Aravena et al. 2013 ADS

ApJ paper examining the conditions of the ISM in one of our best characterized sources: Bothwell et al. 2013 ADS

paper (submitted to ApJ) reporting the composite mm spectrum of SMGs: Spilker et al. 2013

Articles about our results:

A nice review in Nature by Andrew Blain: News & Views also here
LA Times
Discovery Magazine
Science Daily
Phys.Org
Universe Today
Space.com
Kavli Spotlight

Press Releases:

U. Chicago March 2013
Caltech March 2013
ESO March 2013
NSF March 2013
NRAO March 2013
Arizona March 2013
McGill March 2013
Max Planck March 2013

Talks:

A recent talk (somewhat redacted):
May 2013

Some older talks (external links):
SNOWPAC 2012
UCI submm 2011
Aspen 2008

Links:

Internal SPT SMG wiki

Public SPT page here: SPT

Collaboration:

James Aguirre (U Penn)
Manuel Aravena (ESO)
Matt Ashby (CfA)
Matthieu Bethermin (ESO)
Matt Bothwell (Cambridge)
Mark Brodwin (U Missouri)
John Carlstrom (U Chicago)
Scott Chapman (Dalhousie)
Tom Crawford (U Chicago)
Carlos DeBreuck (ESO)
Chris Fassnacht (Davis)
Anthony Gonzalez (U Florida)
Thomas Greve (UCL)
Bitten Gullberg (ESO)
Yashar Hezaveh (Stanford)
Jingzhe Ma (U Florida)
Matt Malkan (UCLA)
Dan Marrone (Arizona)
Eric Murphy (IPAC)
Kaja Rotermund (Dalhousie)
Justin Spilker (Arizona)
Brian Stalder (Harvard)
Antony Stark (CfA)
Maria Strandet (MPIfR)
Joaquin Vieira (Caltech/JPL/Illinois)
Axel Weiss (MPIfR)
Niraj Welikala (IAS/Oxford)

Collaboration photo July 2013, Pasadena, CA:



From left to right:
Brian Stalder, Jingzhe Ma, Manuel Aravena, Tony Stark, Maria Strandet, Scott Chapman, Bitten Gullberg, Thomas Greve, Axel Weiss, Kaja Rotermund, James Aguirre, Joaquin Vieira, Anthony Gonzalez, Carlos DeBreuck, Justin Spilker, Niraj Welikala, Matthieu Bethermin, Dan Marrone, Tom Crawford, Wendy Everett, Erik Shirokoff

SPT on the Big Bang Theory:



For questions and inquiries, contact Joaquin Vieira

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