Browsing by Author "Abril-Cabezas, Irene"

Now showing 1 - 7 of 7
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    Atacama Cosmology Telescope: High-resolution component-separated maps across one third of the sky
    (2024) Coulton, William; Madhavacheril, Mathew S.; Duivenvoorden, Adriaan J.; Hill, J. Colin; 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; Chesmore, Grace E.; Cho, Hsiao-Mei; Choi, Steve K.; Clark, Susan E.; Rosado, Rodrigo Cordova; Cothard, Nicholas F.; Coughlin, Kevin; Crowley, Kevin T.; Devlin, Mark J.; Dicker, Simon; Doze, Peter; Duell, Cody J.; Duff, Shannon M.; Dunkley, Jo; Dunner, 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; Halpern, Mark; Han, Dongwon; Hasselfield, Matthew; Healy, Erin; Henderson, Shawn; Hensley, Brandon; Hervias-Caimapo, Carlos; 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; 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.; van Marrewijk, Joshiwa; McCarthy, Fiona; 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; Qu, Frank J.; Radiconi, Federico; Robertson, Naomi; Rojas, Felipe; Sakuma, Tai; Salatino, Maria; Schaan, Emmanuel; Schmitt, Benjamin L.; Sehgal, Neelima; Shaikh, Shabbir; Sherwin, Blake D.; 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; Vargas, Cristian; Vavagiakis, Eve M.; Wagoner, Kasey; Wang, Yuhan; Wenzl, Lukas; Wollack, Edward J.; Xu, Zhilei; Zago, Fernando; Zheng, Kaiwen
    Observations of the millimeter sky contain valuable information on a number of signals, including the blackbody cosmic microwave background (CMB), Galactic emissions, and the Compton-y distortion due to the thermal Sunyaev-Zel'dovich (tSZ) effect. Extracting new insight into cosmological and astrophysical questions often requires combining multiwavelength observations to spectrally isolate one component. In this work, we present a new arc-minute-resolution Compton-y map, which traces out the line-of-sightintegrated electron pressure, as well as maps of the CMB in intensity and E-mode polarization, across a third of the sky (around 13; 000 deg2). We produce these through a joint analysis of data from the Atacama Cosmology Telescope (ACT) data release 4 and 6 at frequencies of roughly 93, 148, and 225 GHz, together with data from the Planck satellite at frequencies between 30 and 545 GHz. We present detailed verification of an internal linear combination pipeline implemented in a needlet frame that allows us to efficiently suppress Galactic contamination and account for spatial variations in the ACT instrument noise. These maps provide a significant advance, in noise levels and resolution, over the existing Planck componentseparated maps and will enable a host of science goals including studies of cluster and galaxy astrophysics, inferences of the cosmic velocity field, primordial non-Gaussianity searches, and gravitational lensing reconstruction of the CMB.
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    Impact of Galactic dust non-Gaussianity on searches for B-modes from inflation
    (2024) Abril-Cabezas, Irene; Hervias-Caimapo, Carlos; von Hausegger, Sebastian; Sherwin, Blake D.; Alonso, David
    A key challenge in the search for primordial B-modes is the presence of polarized Galactic foregrounds, especially thermal dust emission. Power-spectrum-based analysis methods generally assume the foregrounds to be Gaussian random fields when constructing a likelihood and computing the covariance matrix. In this paper, we investigate how non-Gaussianity in the dust field instead affects CMB and foreground parameter inference in the context of inflationary B-mode searches, capturing this effect via modifications to the dust power-spectrum covariance matrix. For upcoming experiments such as the Simons Observatory, we find no dependence of the tensor-to-scalar ratio uncertainty sigma(r) on the degree of dust non-Gaussianity or the nature of the dust covariance matrix. We provide an explanation of this result, noting that when frequency decorrelation is negligible, dust in mid-frequency channels is cleaned using high-frequency data in a way that is independent of the spatial statistics of dust. We show that our results hold also for non-zero levels of frequency decorrelation that are compatible with existing data. We find, however, that neglecting the impact of dust non-Gaussianity in the covariance matrix can lead to inaccuracies in goodness-of-fit metrics. Care must thus be taken when using such metrics to test B-mode spectra and models, although we show that any such problems can be mitigated by using only cleaned spectrum combinations when computing goodness-of-fit statistics.
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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: Cosmology from Cross-correlations of unWISE Galaxies and ACT DR6 CMB Lensing
    (2024) Farren, Gerrit S.; Krolewski, Alex; MacCrann, Niall; Ferraro, Simone; Abril-Cabezas, Irene; An, Rui; Atkins, Zachary; Battaglia, Nicholas; Bond, J. Richard; Calabrese, Erminia; Choi, Steve K.; Darwish, Omar; Devlin, Mark J.; Duivenvoorden, Adriaan J.; Dunkley, Jo; Hill, J. Colin; Hilton, Matt; Huffenberger, Kevin M.; Kim, Joshua; Louis, Thibaut; Madhavacheril, Mathew S.; Marques, Gabriela A.; McMahon, Jeff; Moodley, Kavilan; Page, Lyman A.; Partridge, Bruce; Qu, Frank J.; Schaan, Emmanuel; Sehgal, Neelima; Sherwin, Blake D.; Sifon, Cristobal; Staggs, Suzanne T.; Van Engelen, Alexander; Vargas, Cristian; Wenzl, Lukas; White, Martin; Wollack, Edward J.
    We present tomographic measurements of structure growth using cross-correlations of Atacama Cosmology Telescope (ACT) DR6 and Planck cosmic microwave background (CMB) lensing maps with the unWISE Blue and Green galaxy samples, which span the redshift ranges 0.2 less than or similar to z less than or similar to 1.1 and 0.3 less than or similar to z less than or similar to 1.8, respectively. We improve on prior unWISE cross-correlations not just by making use of the new, high-precision ACT DR6 lensing maps, but also by including additional spectroscopic data for redshift calibration and by analyzing our measurements with a more flexible theoretical model. We determine the amplitude of matter fluctuations at low redshifts (z similar or equal to 0.2-1.6), finding S 8 equivalent to sigma 8 ( Omega m / 0.3 ) 0.5 = 0.813 +/- 0.021 using the ACT cross-correlation alone and S 8 = 0.810 +/- 0.015 with a combination of Planck and ACT cross-correlations; these measurements are fully consistent with the predictions from primary CMB measurements assuming standard structure growth. The addition of baryon acoustic oscillation data breaks the degeneracy between sigma 8 and Omega m , allowing us to measure sigma 8 = 0.813 +/- 0.020 from the cross-correlation of unWISE with ACT and sigma 8 = 0.813 +/- 0.015 from the combination of cross-correlations with ACT and Planck. These results also agree with the expectations from primary CMB extrapolations in Lambda CDM cosmology; the consistency of sigma 8 derived from our two redshift samples at z similar to 0.6 and 1.1 provides a further check of our cosmological model. Our results suggest that structure formation on linear scales is well described by Lambda CDM even down to low redshifts z less than or similar to 1.
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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 Atacama Cosmology Telescope: Mitigating the Impact of Extragalactic Foregrounds for the DR6 Cosmic Microwave Background Lensing Analysis
    (2024) MacCrann, Niall; Sherwin, Blake D.; Qu, Frank J.; Namikawa, Toshiya; Madhavacheril, Mathew S.; Abril-Cabezas, Irene; An, Rui; Austermann, Jason E.; Battaglia, Nicholas; Battistelli, Elia S.; Beall, James A.; Bolliet, Boris; Bond, J. Richard; Cai, Hongbo; Calabrese, Erminia; Coulton, William R.; Darwish, Omar; Duff, Shannon M.; Duivenvoorden, Adriaan J.; Dunkley, Jo; Farren, Gerrit S.; Ferraro, Simone; Golec, Joseph E.; Guan, Yilun; Han, Dongwon; Hervias-Caimapo, Carlos; Hill, J. Colin; Hilton, Matt; Hlozek, Renee; Hubmayr, Johannes; Kim, Joshua; Li, Zack; Kosowsky, Arthur; Louis, Thibaut; McMahon, Jeff; A. Marques, Gabriela; Moodley, Kavilan; Naess, Sigurd; Niemack, Michael D.; Page, Lyman; Partridge, Bruce; Schaan, Emmanuel; Sehgal, Neelima; Sifon, Cristobal; Wollack, Edward J.; Salatino, Maria; Ullom, Joel N.; Van Lanen, Jeff; Van Engelen, Alexander; Wenzl, Lukas
    We investigate the impact and mitigation of extragalactic foregrounds for the cosmic microwave background (CMB) lensing power spectrum analysis of Atacama Cosmology Telescope (ACT) data release 6 (DR6) data. Two independent microwave sky simulations are used to test a range of mitigation strategies. We demonstrate that finding and then subtracting point sources, finding and then subtracting models of clusters, and using a profile bias-hardened lensing estimator together reduce the fractional biases to well below statistical uncertainties, with the inferred lensing amplitude, A lens, biased by less than 0.2 sigma. We also show that another method where a model for the cosmic infrared background (CIB) contribution is deprojected and high-frequency data from Planck is included has similar performance. Other frequency-cleaned options do not perform as well, either incurring a large noise cost or resulting in biased recovery of the lensing spectrum. In addition to these simulation-based tests, we also present null tests on the ACT DR6 data for sensitivity of our lensing spectrum estimation to differences in foreground levels between the two ACT frequencies used, while nulling the CMB lensing signal. These tests pass whether the nulling is performed at the map or bandpower level. The CIB-deprojected measurement performed on the DR6 data is consistent with our baseline measurement, implying that contamination from the CIB is unlikely to significantly bias the DR6 lensing spectrum. This collection of tests gives confidence that the ACT DR6 lensing measurements and cosmological constraints presented in companion papers to this work are robust to extragalactic foregrounds.
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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.