arXiv subjects

Abigail Flowers

Publications and source records attributed to Abigail Flowers.

3 recordsLinked to original sources

arXiv2026

A Constraint on Dark Matter Self-Interaction from Combined Strong Lensing and Stellar Kinematics in MACS J0138-2155

Self-Interacting Dark Matter (SIDM) represents a compelling alternative to collisionless dark matter, with diverse phenomenological signals from dwarf galaxy to galaxy cluster scales. We present new constraints on the SIDM cross section from the galaxy cluster MACS J0138-2155, host to the strongly lensed supernovae Requiem and Encore. Our analysis combines strong gravitational lensing with spatially resolved stellar kinematics of the central galaxy, employing several methodological advances over previous cluster-scale SIDM studies. The result is a self-consistent measurement of the density profile of MACS J0138-2155 across two orders of magnitude in radius. Our lensing and kinematics analyses individually yield highly consistent results, and from their combination we report a 95% confidence upper limit on the SIDM cross section of $σ/m < 0.613$ cm$^2$/g, at an interaction velocity of $\langle v_\text{pair}\rangle < 2090$ km/s. This constraint, derived from the most detailed single-system analysis to date, is competitive with previous cluster-scale limits while demonstrating the power of combining complementary gravitational probes. The methodology developed here advances precision cluster lens modeling and will inform future studies of dark matter physics, as well as time-delay cosmography in this unique strong lensing system. Additionally, our results imply SN Requiem will reappear sooner than previously reported, with a 1$σ$ CL between January 2027 and November 2028 at H$_0 = 67.7$ km s$^{-1}$ Mpc$^{-1}$.

astro-ph.CO↗

arXiv2025

Characterisation of the Bedretto Underground Site for Fundamental Physics Experiments

Underground laboratories provide the ultra-low background and low-vibration environments essential for rare-event searches, gravitational-wave detection, and quantum-sensing technologies. We report a comprehensive environmental characterisation of the Bedretto tunnel in Ticino, Switzerland, a site offering horizontal access, excellent infrastructure, and the potential to be be Europe's second-deepest and quietest underground laboratory. At the prospective physics site, located beneath an overburden exceeding 1400 m, we measure the cosmic-muon, gamma-ray, and neutron fluxes, as well as the radon concentration, magnetic-field spectrum, and seismic backgrounds. The muon flux is suppressed by six orders of magnitude relative to the surface, consistent with an effective depth of about 4000 metre water equivalent, gamma-ray and neutron measurements reflect the local geology and guide shielding requirements for future particle and nuclear physics experiments. Magnetic and seismic noise levels are found to be exceptionally low, meeting or exceeding the criteria for next-generation atom-interferometric gravitational-wave detectors. These results establish the site as a highly competitive, accessible deep-underground location for fundamental-physics experiments.

astro-ph.IM↗

arXiv2025

Spectroscopic and X-ray Modeling of the Strong Lensing Galaxy Cluster MACS J0138.0-2155

We model the total mass and galactic substructure in the strong lensing galaxy cluster MACS J0138.0-2155 using a combination of Chandra X-ray data, Multi-Unit Spectroscopic Explorer (MUSE) spectroscopy, and Hubble Space Telescope imaging. MACS J0138.0-2155 lenses a source galaxy at $z=1.95$ which hosts two strongly lensed supernovae, Requiem and Encore. We find MACS J0138.0-2155 to have an X-ray temperature of $6.7\pm0.4$ keV and a velocity dispersion of cluster member galaxies of $718^{+132}_{-182}$ km s$^{-1}$. These lead to the mass estimates for the cluster of $M_{500} = 5.2^{+1.5}_{-1.2} \times 10^{14} M_\odot$ from the X-ray results and $M_{200} \approx 3.6^{+2.0}_{-2.7} \times 10 ^{14} M_{\odot}$ from the velocity dispersion results. The round morphology of the X-ray emission indicates that this cluster is relaxed with an ellipticity within the lensing region of $e=0.12\pm0.03$. Using 18 of the brightest, non-blended, quiescent galaxies, we fit the cluster specific Faber-Jackson relation, including a set of 81 variations in the analysis choices to estimate the systematic uncertainties in our results. We find a slope of $α= 0.26 \pm 0.06 (\mathrm{stat.}) \pm 0.03 (\mathrm{sys.})$ with an intrinsic scatter of $Δσ= 31^{+8}_{-6} (\mathrm{stat.}) \pm 4 (\mathrm{sys.})$ km s$^{-1}$ at a reference velocity dispersion of $\sim 220$ km s$^{-1}$. We also report on significant galaxies along the line-of-sight potentially impacting the lens modeling, including a massive galaxy with stellar velocity dispersion of $236 \pm 3$ km s$^{-1}$ which lies close in projection to the central cluster galaxy. This galaxy is part of a small group at a slightly higher redshift than the cluster.

astro-ph.CO↗