Above: Thumbnails of high-redshift strongly-lensed submillimeter galaxies (SMGs) from the South Pole Telescope (SPT) survey. The blue images are from the Hubble Space Telescope and trace the stellar emission from the foreground lens at z~1. The red images are from the Atacama Large Millimeter/submillimeter Array (ALMA) and trace the dust emission from the background lensed galaxy at z~4.
SPT-SMGs: 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.
The South Pole Telescope's (SPT) SZ survey has systematically identified a large number of high-redshift strongly gravitationally lensed starburst galaxies in a 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. 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 magnification provides a reduction in the integration times required to detect lensed sources, makes weak spectral lines accessible, and increases the resolving power of our telescopes.
Over the past decade, we conducted a spectroscopic redshift survey with the Atacama Large Millimeter Array (ALMA) targeting 81 sources from the first-generation SPT survey. We obtained redshifts for the entire sample and determined that roughly half of these sources lie at z>4, indicating the fraction of dusty starburst galaxies at high redshift is far higher than previously thought. The highest-redshift source, SPT0311-58 at z=6.9, demonstrates 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 that the targets are mostly strongly gravitationally lensed by foreground structure, and enabling us to make detailed and robust lens models. Around 10% of the targeted sources were found to be protocluster candidates.
Schematic of gravitational lensing for one of the SPT-SMGs. Credit: ALMA (ESO/NRAO/NAOJ), L. Calçada (ESO), Y. Hezaveh et al.
The figure represents all the spectra obtained via ALMA band 3 observations for the SPT-SMGs. The different bright lines are carbon monoxide (CO) lines which helped us determine the redshift. The final distribution of redshifts for our SMGs is published in Reuter et al. (2020) and the stacked spectra is presented in Reuter et al. (2023). The data from various tables and figures is available on github.
Above: Movie showcasing [CII] data for SPT0311-58 at z=6.9. The analysis is presented in Spilker et al. (2022) and the movie is available on github.
Above: SPT SMGs observed with the James Webb Space Telescope (JWST). The larger image is from NIRCam and the inset is MIRI.
Collaboration in the News
Collaboration Members
Yordanka Apostolovski - Universidad de Valparaiso
Manuel Aravena - Universidad Andres Bello
Melanie Archipley - University of Chicago
Matthew Ashby - Harvard-Smithsonian Center for Astrophysics
Bradford Benson - University of Chicago
Matthieu Bethermin - Laboratoire d'Astrophysique de Marseille
Jack Birkin - Texas A&M University
Simon Birrer - Stony Brook University
Lindsey Bleem - Argonne National Laboratory
Rebecca Canning - University of Portsmouth
John Carlstrom - University of Chicago
Jared Cathey - University of Florida
Scott Chapman - University of British Columbia
Tom Crawford - University of Chicago
Roger Deane - University of Pretoria
Veronica Dike - University of Illinois, Urbana-Champaign
Frank Fu - University of Illinois, Urbana-Champaign
Anthony Gonzalez - University of Florida
Thomas Greve - Cosmic Dawn Center (DAWN) / DTU Space
Gayathri Gururajan - Scuola Internazionale Superiore Studi Avanzati (SISSA)
Chris Hayward - Flatiron CCA
Yashar Hezaveh - University of Montreal
Ryley Hill - University of British Columbia
Gil Holder - University of Illinois, Urbana-Champaign
Bill Holzapfel - University of California Berkeley
Sree Vani Jarugula - Fermilab
Seonwoo Kim - University of Illinois, Urbana-Champaign
Matt Malkan - University of California Los Angeles
Dan Marrone - University of Arizona
Karl Menten - Max Planck Institute
Eric Murphy - University of Virginia
Desika Narayanan - University of Florida
Sydnee O'Donnell - University of Illinois, Urbana-Champaign
Zhaodi Pan - Argonne National Laboratory
Kedar Phadke - University of Illinois, Urbana-Champaign
Ana Posses - Texas A&M University
Christian Reichardt - The University of Melbourne
Cassie Reuter - University of California Berkeley
Kaja Rotermund - Dalhousie University
Justin Spilker - Texas A&M University
Tony Stark - Harvard-Smithsonian Center for Astrophysics
Nikolaus Sulzenauer - Max Planck Institute
Mathilde Van Cuyck - University of Illinois, Urbana-Champaign
Joaquin Vieira - University of Illinois, Urbana-Champaign
David Vizgan - University of Illinois, Urbana-Champaign
Yujie Wan - University of Illinois, Urbana-Champaign
Axel Weiss - Max Planck Institute
Briana Wirag - Texas A&M University
Nan Zhang - University of Illinois, Urbana-Champaign
Dazhi Zhou - University of British Columbia
From left to right:
Matt Malkan, Daniel Cunningham, Ryley Hill, Katrina Litke, Sreevani Jarugula, Joaquin Vieira, Kedar Phadke, Cassie Reuter, Justin Spilker, Antony Stark, Amelia Mangian, Chris Hayward, Melanie Archipley, Chenxing Dong, George Wang, Frank Fu
From left to right:
Front: Frank Fu, Sidney Lower, Carlos DeBreuck, Matt Malkan, Cassie Reuter, Jingzhe Ma, Sreevani Jarugula, Yordanka Apostolovski, Katrina Litke
Middle: Dan Marrone, Anthony Gonzalez, Justin Spilker, Chris Hayward, Scott Chapman, Warren Morningstar, Antony Stark, Chenxing Dong, Kedar Phadke
Back: Axel Weiss, Chian-Chou Chen, Thomas Greve, Manuel Aravena
From left to right:
Matt Malkan, Brian Stalder, Axel Weiss, Chian-Chou Chen, Warren Morningstar, Kedar Phadke, Joaquin Vieira, Matthieu Bethermin, Carlos DeBreuck, Dan Marrone, Chris Hayward, Justin Spilker, Manuel Aravena, Katrina Litke, Scott Chapman, Sreevani Jarugula, Chenxing Dong, Daniel Cunningham
From left to right:
David Booke, Sidney Lower, Jennifer Li, Matt Malkan, Sreevani Jarugula, Thomas Greve, Dan Marrone, Tony Stark, Brian Stalder, Manuel Aravena, Anthony Gonzalez, Joaquin Vieira, Carlos DeBreuck, Maria Strandet, Axel Weiss, Desika Narayanan, Jingzhe Ma, Kaja Rotermund, Chris Hayward, Katrina Litke, Justin Spilker, Tim Miller
From left to right:
Joaquin Vieira, Kaja Rotermund, Katrina Litke, Jingzhe Ma, Tony Stark, Justin Spilker, Matt Malkan, Yashar Hezaveh, Axel Weiss, Scott Chapman, Anthony Gonzalez, Carlos DeBreuck, Dan Marrone, Maria Strandet
From left to right:
Joaquin Vieira, Dan Marrone, Axel Weiss, Carlos DeBreuck, Niraj Welikala, Maria Strandet, Thomas Greve, Bitten Gullberg, Chris Fassnacht, Justin Spilker, Kate Husband, Matt Malkan, Matt Bothwell, Yashar Hezaveh, Matthieu Bethermin
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
From left to right:
Scott Chapman, Thomas Greve, James Aguirre, Yashar Hezaveh, Dan Marrone, Chris Fassnacht, Niraj Welikala, Anthony Gonzalez, Brian Stalder, Mark Brodwin, Matt Bothwell, Justin Spilker, Joaquin Vieira, Tom Crawford, Axel Weiss