July 2026
Jul 30, Thursday
4 pm (LBL RPM)
Jose Bernal, IFCA
LBL 50-5132 and ZOOM
Line-Intensity Mapping: progress and lessons learned
Line-Intensity mapping (LIM) uses the integrated flux along the line of sight as tracer of the LSS. Using relatively low-aperture telescopes, it recovers radial information targeting known spectral lines discarding the continuum emission, which makes the experiments cheaper compared with galaxy surveys. Mapping the intensity fluctuations of an array of lines from HI 21cm to optical-UV lines offers a unique opportunity to probe redshifts well beyond the reach of other cosmological observations, access regimes that cannot be explored otherwise, and exploit the enormous potential of cross-correlations with other measurements. This promises to deepen our understanding of various questions related to galaxy formation and evolution, cosmology, and fundamental physics. In this talk I will cover the current status of LIM, focusing on recent developments of the HETDEX and MeerKLASS collaborations and the lessons learned in this pathfinder stage that must be applied for future, larger surveys.
August 2026
September 2026
Sep 1, Tuesday
1:10 pm (BCCP/Cosmology seminar)
1 minute intro slides
Campbell 131
Sep 8, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Sam Goldstein, Columbia
Campbell 131
Squeezing New Physics out of Cosmological Surveys: From Axions to Cosmological Colliders
Cosmic microwave background (CMB) and large-scale structure (LSS) surveys offer an unprecedented opportunity to search for physics beyond the Standard Model. Fully realizing their potential, however, requires new methods to extract subtle signals from increasingly complex cosmological datasets, where astrophysical foregrounds, nonlinear structure formation, and observational systematics can obscure or mimic the signatures of interest. In the first half of the talk, I will describe the resonant conversion of CMB photons into axions in the magnetized plasma within galactic halos. This effect modifies the blackbody spectrum of the CMB and can be isolated using multifrequency cleaning techniques. I will present results from the first search for this effect, using unWISE galaxies and Planck CMB maps, with a particular focus on foreground mitigation strategies. I will then present results from a follow-up search that incorporates ACT data via a new component-separation pipeline, yielding significantly improved constraints on the axion-photon coupling, and comment on its application to future Simons Observatory data. In the second half of the talk, I will turn to galaxy surveys as a powerful probe of inflation, focusing on signatures of ultra-high-energy particles accessible via the cosmological collider. I will present new methods for extracting these signatures with LSS data and conclude with the first LSS constraint on tauNL, the amplitude of the primordial four-point function generated in multi-field inflation models, via its imprint on scale-dependent bias. This analysis, which uses DESI DR2 quasars, constitutes the largest-scale three-dimensional power-spectrum measurement to date, underscoring the unique sensitivity of galaxy clustering to fundamental physics while highlighting several challenges of using LSS observations on ultra-large scales. Together, these results demonstrate the potential of ongoing and upcoming CMB and LSS surveys to probe physics beyond the Standard Model.
Sep 15, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Carmen Embil-Villagra, Cambridge
Campbell 131
Sep 22, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Kritti Sharma, Caltech
Campbell 131
Sep 29, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Lurdes Ondaro, Cambridge
Campbell 131
October 2026
Oct 6, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Jared Siegel, Princeton
Campbell 131
Oct 13, Tuesday
1:10 pm (BCCP/Cosmology seminar)
tbd,
Campbell 131
Oct 20, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Cliff Burgess, McMaster and Perimeter
Campbell 131
Oct 27, Tuesday
1:10 pm (BCCP/Cosmology seminar)
tbd,
Campbell 131
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