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C. Fox

Publications and source records attributed to C. Fox.

2 recordsLinked to original sources

Core Mass Estimates in Strong Lensing Galaxy Clusters: a Comparison Between Masses Obtained from Detailed Lens Models, Single-Halo Lens Models, and Einstein Radii

The core mass of galaxy clusters is both an important anchor of the radial mass distribution profile and probe of structure formation. With thousands of strong lensing galaxy clusters being discovered by current and upcoming surveys, timely, efficient, and accurate core mass estimates are needed. We assess the results of two efficient methods to estimate the core mass of strong lensing clusters: the mass enclosed by the Einstein radius ($M_{corr}(<\theta_E)$ where $\theta_{\rm E}$ is approximated from arc positions; Remolina Gonz\'{a}lez et al. 2020), and single-halo lens model ($M_{\rm{SHM}}(<\rm{e}\theta_{\rm{E}})$; Remolina Gonz\'{a}lez et al. 2021), against measurements from publicly available detailed lens models ($M_{\rm{DLM}}$) of the same clusters. We use data from the Sloan Giant Arc Survey, the Reionization Lensing Cluster Survey, the \Hubble\ Frontier Fields, and the Cluster Lensing and Supernova Survey with \Hubble. We find a scatter of $18.3\%$ ($8.4\%$) with a bias of $-7.5\%$ ($0.4\%$) between $M_{corr}(<\theta_E)$ ($M_{\rm{SHM}}(<\rm{e}\theta_{\rm{E}})$) and $M_{\rm{DLM}}$. Last, we compare the statistical uncertainties measured in this work to those from simulations. This work demonstrates the successful application of these methods to observational data. As the effort to efficiently model the mass distribution of strong lensing galaxy clusters continues, we need fast, reliable methods to advance the field.

astro-ph.CO

Direct measurement of the 14N(p,g)15O S-factor

We have measured the 14N(p,g)15O excitation function for energies in the range E_p = 155--524 keV. Fits of these data using R-matrix theory yield a value for the S-factor at zero energy of 1.64(17) keV b, which is significantly smaller than the result of a previous direct measurement. The corresponding reduction in the stellar reaction rate for 14N(p,g)15O has a number of interesting consequences, including an impact on estimates for the age of the Galaxy derived from globular clusters.

nucl-ex