Browsing by Author "Challinor, Anthony"

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    The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and Its Implications for Structure Growth
    (2024) Qu, Frank; Sherwin, Blake D.; Madhavacheril, Mathew S.; Han, Dongwon; Crowley, Kevin T.; Abril-Cabezas, Irene; Ade, Peter A. R.; Aiola, Simone; Alford, Tommy; Amiri, Mandana; Amodeo, Stefania; An, Rui; Atkins, Zachary; Austermann, Jason E.; Battaglia, Nicholas; Battistelli, Elia Stefano; Beall, James A.; Bean, Rachel; Beringue, Benjamin; Bhandarkar, Tanay; Biermann, Emily; Bolliet, Boris; Bond, J. Richard; Cai, Hongbo; Calabrese, Erminia; Calafut, Victoria; Capalbo, Valentina; Carrero, Felipe; Carron, Julien; Challinor, Anthony; Chesmore, Grace E.; Cho, Hsiao-Mei; Choi, Steve K.; Clark, Susan E.; Rosado, Rodrigo Cordova; Cothard, Nicholas F.; Coughlin, Kevin; Coulton, William; Dalal, Roohi; Darwish, Omar; Devlin, Mark J.; Dicker, Simon; Doze, Peter; Duell, Cody J.; Duff, Shannon M.; Duivenvoorden, Adriaan J.; Dunkley, Jo; Dunner, Rolando; Fanfani, Valentina; Fankhanel, Max; Farren, Gerrit; Ferraro, Simone; Freundt, Rodrigo; Fuzia, Brittany; Gallardo, Patricio A.; Garrido, Xavier; Gluscevic, Vera; Golec, Joseph E.; Guan, Yilun; Halpern, Mark; Harrison, Ian; Hasselfield, Matthew; Healy, Erin; Henderson, Shawn; Hensley, Brandon; Hervias-Caimapo, Carlos; Hill, J. Colin; Hilton, Gene C.; Hilton, Matt; Hincks, Adam D.; Hlozek, Renee; Ho, Shuay-Pwu Patty; Huber, Zachary B.; Hubmayr, Johannes; Huffenberger, Kevin M.; Hughes, John P.; Irwin, Kent; Isopi, Giovanni; Jense, Hidde T.; Keller, Ben; Kim, Joshua; Knowles, Kenda; Koopman, Brian J.; Kosowsky, Arthur; Kramer, Darby; Kusiak, Aleksandra; La Posta, Adrien; Lague, Alex; Lakey, Victoria; Lee, Eunseong; Li, Zack; Li, Yaqiong; Limon, Michele; Lokken, Martine; Louis, Thibaut; Lungu, Marius; MacCrann, Niall; MacInnis, Amanda; Maldonado, Diego; Maldonado, Felipe; Mallaby-Kay, Maya; Marques, Gabriela A.; McMahon, Jeff; Mehta, Yogesh; Menanteau, Felipe; Moodley, Kavilan; Morris, Thomas W.; Mroczkowski, Tony; Naess, Sigurd; Namikawa, Toshiya; Nati, Federico; Newburgh, Laura; Nicola, Andrina; Niemack, Michael D.; Nolta, Michael R.; Orlowski-Scherer, John; Page, Lyman A.; Pandey, Shivam; Partridge, Bruce; Prince, Heather; Puddu, Roberto; Radiconi, Federico; Robertson, Naomi; Rojas, Felipe; Sakuma, Tai; Salatino, Maria; Schaan, Emmanuel; Schmitt, Benjamin L.; Sehgal, Neelima; Shaikh, Shabbir; Sierra, Carlos; Sievers, Jon; Sifon, Cristobal; Simon, Sara; Sonka, Rita; Spergel, David N.; Staggs, Suzanne T.; Storer, Emilie; Switzer, Eric R.; Tampier, Niklas; Thornton, Robert; Trac, Hy; Treu, Jesse; Tucker, Carole; Ullom, Joel; Vale, Leila R.; Van Engelen, Alexander; Van Lanen, Jeff; van Marrewijk, Joshiwa; Vargas, Cristian; Vavagiakis, Eve M.; Wagoner, Kasey; Wang, Yuhan; Wenzl, Lukas; Wollack, Edward J.; Xu, Zhilei; Zago, Fernando; Zheng, Kaiwen
    We present new measurements of cosmic microwave background (CMB) lensing over 9400 deg2 of the sky. These lensing measurements are derived from the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) CMB data set, which consists of five seasons of ACT CMB temperature and polarization observations. We determine the amplitude of the CMB lensing power spectrum at 2.3% precision (43 sigma significance) using a novel pipeline that minimizes sensitivity to foregrounds and to noise properties. To ensure that our results are robust, we analyze an extensive set of null tests, consistency tests, and systematic error estimates and employ a blinded analysis framework. Our CMB lensing power spectrum measurement provides constraints on the amplitude of cosmic structure that do not depend on Planck or galaxy survey data, thus giving independent information about large-scale structure growth and potential tensions in structure measurements. The baseline spectrum is well fit by a lensing amplitude of A lens = 1.013 +/- 0.023 relative to the Planck 2018 CMB power spectra best-fit Lambda CDM model and A lens = 1.005 +/- 0.023 relative to the ACT DR4 + WMAP best-fit model. From our lensing power spectrum measurement, we derive constraints on the parameter combination S8CMBL equivalent to sigma 8 omega m/0.30.25 of S8CMBL=0.818 +/- 0.022 from ACT DR6 CMB lensing alone and S8CMBL=0.813 +/- 0.018 when combining ACT DR6 and Planck NPIPE CMB lensing power spectra. These results are in excellent agreement with Lambda CDM model constraints from Planck or ACT DR4 + WMAP CMB power spectrum measurements. Our lensing measurements from redshifts z similar to 0.5-5 are thus fully consistent with Lambda CDM structure growth predictions based on CMB anisotropies probing primarily z similar to 1100. We find no evidence for a suppression of the amplitude of cosmic structure at low redshifts.
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    The Atacama Cosmology Telescope: DR6 Gravitational Lensing Map and Cosmological Parameters
    (2024) Madhavacheril, Mathew S.; Qu, Frank J.; Sherwin, Blake D.; Maccrann, Niall; Li, Yaqiong; Abril-Cabezas, Irene; Ade, Peter A. R.; Aiola, Simone; Alford, Tommy; Amiri, Mandana; Amodeo, Stefania; An, Rui; Atkins, Zachary; Austermann, Jason E.; Battaglia, Nicholas; Battistelli, Elia Stefano; Beall, James A.; Bean, Rachel; Beringue, Benjamin; Bhandarkar, Tanay; Biermann, Emily; Bolliet, Boris; Bond, J. Richard; Cai, Hongbo; Calabrese, Erminia; Calafut, Victoria; Capalbo, Valentina; Carrero, Felipe; Challinor, Anthony; Chesmore, Grace E.; Cho, Hsiao-mei; Choi, Steve K.; Clark, Susan E.; Rosado, Rodrigo Cordova; Cothard, Nicholas F.; Coughlin, Kevin; Coulton, William; Crowley, Kevin T.; Dalal, Roohi; Darwish, Omar; Devlin, Mark J.; Dicker, Simon; Doze, Peter; Duell, Cody J.; Duff, Shannon M.; Duivenvoorden, Adriaan J.; Dunkley, Jo; Duenner, Rolando; Fanfani, Valentina; Fankhanel, Max; Farren, Gerrit; Ferraro, Simone; Freundt, Rodrigo; Fuzia, Brittany; Gallardo, Patricio A.; Garrido, Xavier; Givans, Jahmour; Gluscevic, Vera; Golec, Joseph E.; Guan, Yilun; Hall, Kirsten R.; Halpern, Mark; Han, Dongwon; Harrison, Ian; Hasselfield, Matthew; Healy, Erin; Henderson, Shawn; Hensley, Brandon; Hervias-Caimapo, Carlos; Hill, J. Colin; Hilton, Gene C.; Hilton, Matt; Hincks, Adam D.; Hlozek, Renee; Ho, Shuay-Pwu Patty; Huber, Zachary B.; Hubmayr, Johannes; Huffenberger, Kevin M.; Hughes, John P.; Irwin, Kent; Isopi, Giovanni; Jense, Hidde T.; Keller, Ben; Kim, Joshua; Knowles, Kenda; Koopman, Brian J.; Kosowsky, Arthur; Kramer, Darby; Kusiak, Aleksandra; La Posta, Adrien; Lague, Alex; Lakey, Victoria; Lee, Eunseong; Li, Zack; Limon, Michele; Lokken, Martine; Louis, Thibaut; Lungu, Marius; Macinnis, Amanda; Maldonado, Diego; Maldonado, Felipe; Mallaby-Kay, Maya; Marques, Gabriela A.; Mcmahon, Jeff; Mehta, Yogesh; Menanteau, Felipe; Moodley, Kavilan; Morris, Thomas W.; Mroczkowski, Tony; Naess, Sigurd; Namikawa, Toshiya; Nati, Federico; Newburgh, Laura; Nicola, Andrina; Niemack, Michael D.; Nolta, Michael R.; Orlowski-Scherer, John; Page, Lyman A.; Pandey, Shivam; Partridge, Bruce; Prince, Heather; Puddu, Roberto; Radiconi, Federico; Robertson, Naomi; Rojas, Felipe; Sakuma, Tai; Salatino, Maria; Schaan, Emmanuel; Schmitt, Benjamin L.; Sehgal, Neelima; Shaikh, Shabbir; Sierra, Carlos; Sievers, Jon; Sifon, Cristobal; Simon, Sara; Sonka, Rita; Spergel, David N.; Staggs, Suzanne T.; Storer, Emilie; Switzer, Eric R.; Tampier, Niklas; Thornton, Robert; Trac, Hy; Treu, Jesse; Tucker, Carole; Ullom, Joel; Vale, Leila R.; Van Engelen, Alexander; Van Lanen, Jeff; van Marrewijk, Joshiwa; Vargas, Cristian; Vavagiakis, Eve M.; Wagoner, Kasey; Wang, Yuhan; Wenzl, Lukas; Wollack, Edward J.; Xu, Zhilei; Zago, Fernando; Zheng, Kaiwen
    We present cosmological constraints from a gravitational lensing mass map covering 9400 sq. deg(2). reconstructed from CMB measurements made by the Atacama Cosmology Telescope (ACT) from 2017 to 2021. In combination with BAO measurements (from SDSS and 6dF), we obtain the amplitude of matter fluctuations sigma(8)=0.819 +/- 0.015 at 1.8% precision, S-8 equivalent to sigma(8)(Omega(m)/0.3)(0.5)=0.840 +/- 0.028 and the Hubble constant H-0=(68.3 +/- 1.1)kms(-1)Mpc(-1) at 1.6% precision. A joint constraint with CMB lensing measured by the Planck satellite yields even more precise values: sigma(8)=0.812 +/- 0.013, S-8 equivalent to sigma(8)(Omega m/0.3)(0.5)=0.831 +/- 0.023 and H-0=(68.1 +/- 1.0)kms(-1)Mpc(-1). These measurements agree well with Lambda CDM-model extrapolations from the CMB anisotropies measured by Planck. To compare these constraints to those from the KiDS, DES, and HSC galaxy surveys, we revisit those data sets with a uniform set of assumptions, and find S-8 from all three surveys are lower than that from ACT+Planck lensing by varying levels ranging from 1.7-2.1 sigma. These results motivate further measurements and comparison, not just between the CMB anisotropies and galaxy lensing, but also between CMB lensing probing z similar to 0.5-5 on mostly-linear scales and galaxy lensing at z similar to 0.5 on smaller scales. We combine our CMB lensing measurements with CMB anisotropies to constrain extensions of Lambda CDM, limiting the sum of the neutrino masses to & sum;m(nu)<0.12 eV (95% c.l.), for example. Our results provide independent confirmation that the universe is spatially flat, conforms with general relativity, and is described remarkably well by the Lambda CDM model, while paving a promising path for neutrino physics with gravitational lensing from upcoming ground-based CMB surveys
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    The Simons Observatory: Combining cross-spectral foreground cleaning with multitracer B- mode delensing for improved constraints on inflation
    (2024) Hertig, Emilie; Wolz, Kevin; Namikawa, Toshiya; Lizancos, Anton Baleato; Azzoni, Susanna; Abril-Cabezas, Irene; Alonso, David; Baccigalupi, Carlo; Calabrese, Erminia; Challinor, Anthony; Errard, Josquin; Fabbian, Giulio; Hervias-Caimapo, Carlos; Jost, Baptiste; Krachmalnicoff, Nicoletta; Lonappan, Anto I.; Morshed, Magdy; Pagano, Luca; Sherwin, Blake
    The Simons Observatory (SO), due to start full science operations in early 2025, aims to set tight constraints on inflationary physics by inferring the tensor-to-scalar ratio r from measurements of cosmic microwave background (CMB) polarization B-modes. Its nominal design including three small-aperture telescopes (SATs) targets a precision sigma(r ( r 1 / 4 0) ) <= 0.003 without delensing. Achieving this goal and further reducing uncertainties requires a thorough understanding and mitigation of other large-scale B-mode sources such as Galactic foregrounds and weak gravitational lensing. We present an analysis pipeline aiming to estimate r by including delensing within a cross-spectral likelihood, and demonstrate it for the first time on SO-like simulations accounting for various levels of foreground complexity, inhomogeneous noise and partial sky coverage. As introduced in an earlier SO delensing paper, lensing Bmodes are synthesized using internal CMB lensing reconstructions as well as Planck-like cosmic infrared background maps and LSST-like galaxy density maps. We then extend SO's power-spectrum-based foreground- cleaning algorithm to include all auto- and cross-spectra between the lensing template and the SAT Bmodes in the likelihood function. This allows us to constrain r and the parameters of our foreground model simultaneously. Within this framework, we demonstrate the equivalence of map-based and cross-spectral delensing and use it to motivate an optimized pixel-weighting scheme for power spectrum estimation. We start by validating our pipeline in the simplistic case of uniform foreground spectral energy distributions. In the absence of primordial Bmodes, we find that the 16 statistical uncertainty on r, 6(r), ( r ) , decreases by 37% as a result of delensing. Tensor modes at the level of r 1 / 4 0.01 are successfully detected by our pipeline. Even when using more realistic foreground models including spatial variations in the dust and synchrotron spectral properties, we obtain unbiased estimates of r both with and without delensing by employing the moment-expansion method. In this case, uncertainties are increased due to the higher number of model parameters, and delensing-related improvements range between 27% and 31%. These results constitute the first realistic assessment of the delensing performance at SO's nominal sensitivity level.