arXiv subjects

Carolyn Sealfon

Publications and source records attributed to Carolyn Sealfon.

4 recordsLinked to original sources

arXiv2025

Striving for Equity in Canadian Physics

We discuss a number of new initiatives and events since 2020 which we hope will contribute to advancement of equity issues within the physics community in Canada. A recent analysis of high-school data shows that men are still over-represented in high-school physics courses, and the fraction has not changed in over a decade. Results from a national survey show that despite improvements over the years, the percentage of women and gender diverse physicists drops by around 35% between undergraduate students to those in a physics career. This decline is even more notable among Black, Indigenous, and people of colour (BIPOC) women and gender diverse physicists, whose representation drops by almost 60%. Several programs from the National Sciences and Engineering Research Council (NSERC) have been implemented in order to improve equity, diversity, and accessibility in STEM on a national level, most notably the Chairs for Women in Sciences and Engineering (CSWE) and Chairs for Inclusion in Sciences and Engineering (CISE) initiatives. It is crucial to maintain data collection and support existing as well as new EDI projects in future years as we work to build a more inclusive community of physicists in Canada.

physics.ed-ph↗

arXiv2006

Stacking weak lensing signals of SZ clusters to constrain cluster physics

We show how to place constraints on cluster physics by stacking the weak lensing signals from multiple clusters found through the Sunyaev-Zeldovich (SZ) effect. For a survey that covers about 200 sq. deg. both in SZ and weak lensing observations, the slope and amplitude of the mass vs. SZ luminosity relation can be measured with few percent error for clusters at z~0.5. This can be used to constrain cluster physics, such as the nature of feedback. For example, we can distinguish a pre-heated model from a model with a decreased accretion rate at more than 5sigma. The power to discriminate among different non-gravitational processes in the ICM becomes even stronger if we use the central Compton parameter y_0, which could allow one to distinguish between models with pre-heating, SN feedback and AGN feedback, for example, at more than 5sigma. Measurement of these scaling relations as a function of redshift makes it possible to directly observe e.g., the evolution of the hot gas in clusters. With this approach the mass-L_SZ relation can be calibrated and its uncertainties can be quantified, leading to a more robust determination of cosmological parameters from clusters surveys. The mass-L_SZ relation calibrated in this way from a small area of the sky can be used to determine masses of SZ clusters from very large SZ-only surveys and is nicely complementary to other techniques proposed in the literature.

astro-ph↗

arXiv2005

Smoothing spline primordial power spectrum reconstruction

We reconstruct the shape of the primordial power spectrum (PPS) using a smoothing spline. Our adapted smoothing spline technique provides a complementary method to existing efforts to search for smooth features in the PPS, such as a running spectral index. With this technique we find no significant indication with WMAP first-year data that the PPS deviates from Harrison-Zeldovich and no evidence for loss of power on large scales. We also examine the effect on the cosmological parameters of the additional PPS freedom. Smooth variations in the PPS are not significantly degenerate with other cosmological parameters, but the spline reconstruction greatly increases the errors on the optical depth and baryon fraction.

astro-ph↗

arXiv2005

Limits on deviations from the inverse-square law on megaparsec scales

We present an attempt to constrain deviations from the gravitational inverse-square law on large-scale structure scales. A perturbed law modifies the Poisson equation, which implies a scale-dependent growth of overdensities in the linear regime and thus modifies the power spectrum shape. We use two large-scale structure surveys (the Sloan Digital Sky survey and the Anglo-Australian Two-degree field galaxy redshift survey) to constrain the parameters of two simple modifications of the inverse-square law. We find no evidence for deviations from normal gravity on the scales probed by these surveys (~ 10^(23) m.)

astro-ph↗