- A. Vitrier, et al., — Towards constraining cosmological parameters with SPT-3G observations of
25% of the sky
- The South Pole Telescope (SPT), using its third-generation camera, SPT-3G, is
conducting observations of the cosmic microwave background (CMB) in temperature
and polarization across approximately 10 000 deg$^2$ of the sky at 95, 150, and
220 GHz. This comprehensive dataset should yield stringent constraints on
cosmological parameters. In this work, we explore its potential to address the
Hubble tension by forecasting constraints from temperature, polarization, and
CMB lensing on Early Dark Energy (EDE) and the variation in electron mass in
spatially flat and curved universes. For this purpose, we investigate first
whether analyzing the distinct SPT-3G observation fields independently, as
opposed to as a single, unified region, results in a loss of information
relevant to cosmological parameter estimation. We develop a realistic
temperature and polarization likelihood pipeline capable of analyzing these
fields in these two ways, and subsequently forecast constraints on cosmological
parameters. Our findings indicate that any loss of constraining power from
analyzing the fields separately is primarily concentrated at low multipoles
($\ell$ < 50) and the overall impact on the relative uncertainty on standard
$\Lambda$CDM parameters is minimal (< 3%). Our forecasts suggest that SPT-3G
data should improve by more than a factor of 300 and 3000 the Figure of Merit
(FoM) of the EDE and the varying electron mass models, respectively, when
combined with Planck data. The likelihood pipeline developed and used in this
work is made publicly available online.
- Junhao Zhan, et al., — Built-in precision: Improving cluster cosmology through the
self-calibration of a galaxy cluster sample
- We examine the potential improvements in constraints on the dark energy
equation of state parameter $w$ and matter density $\Omega_M$ from using
clustering information along with number counts for future samples of thermal
Sunyaev-Zel'dovich selected galaxy clusters. We quantify the relative
improvement from including the clustering power spectrum information for three
cluster sample sizes from 33,000 to 140,000 clusters and for three assumed
priors on the mass slope and redshift evolution of the mass-observable
relation. As expected, clustering information has the largest impact when (i)
there are more clusters and (ii) the mass-observable priors are weaker. For
current knowledge of the cluster mass-observable relationship, we find the
addition of clustering information reduces the uncertainty on the dark energy
equation of state, $\sigma(w)$, by factors of $1.023\pm 0.007$ to $1.0790\pm
0.011$, with larger improvements observed with more clusters. Clustering
information is more important for the matter density, with $\sigma(\Omega_M)$
reduced by factors of $1.068 \pm 007$ to $1.145 \pm 0.012$. The improvement in
$w$ constraints from adding clustering information largely vanishes after
tightening priors on the mass-observable relationship by a factor of two. For
weaker priors, we find clustering information improves the determination of the
cluster mass slope and redshift evolution by factors of $1.389 \pm 0.041$ and
$1.340 \pm 0.039$ respectively. These findings highlight that, with the
anticipated surge in cluster detections from next generation surveys,
self-calibration through clustering information will provide an independent
cross-check on the mass slope and redshift evolution of the mass-observable
relationship as well as enhancing the precision achievable from cluster
cosmology.
- L. Balkenhol, et al., — Probing Anisotropic Cosmic Birefringence with Foreground-Marginalised
SPT B-mode Likelihoods
- In this work, we construct foreground-marginalised versions of the SPT-3G D1
and SPTpol cosmic microwave background (CMB) B-mode polarisation likelihoods.
The compression is performed using the CMB-lite framework and we use the
resulting data sets to constrain anisotropic cosmic birefringence, parametrised
by the amplitude of a scale-invariant anisotropic birefringence spectrum,
$A_{\rm CB}$. Using the new SPT-3G data we report a $95\%$ upper limit on
$A_{\rm CB}$ of $ 1.2\times 10^{-4}$, which tightens to $0.53\times 10^{-4}$
when imposing a prior on the amplitude of gravitational lensing based on CMB
lensing reconstruction analyses. These are the tightest constraints on
anisotropic birefringence from BB power spectrum measurements to-date,
demonstrating the constraining power of the South Pole Telescope. The
likelihoods used in this work are made publicly available at
https://github.com/lbalkenhol/candl_data