English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We demonstrate that deep good-seeing VLT/HAWK-I $K_\mathrm{s}$ imagescomplemented with $g$+$z$-band photometry can yield a sensitivity for weaklensing studies of massive galaxy clusters at redshifts \mbox{$0.7\lesssim z\lesssim 1.1$}, which is almost identical to the sensitivity of HST/ACS mosaicsof single-orbit depth. Key reasons for this good performance are the excellentimage quality frequently achievable for $K_\mathrm{s}$ imaging from the ground,a highly effective photometric selection of background galaxies, and a galaxyellipticity dispersion that is noticeably lower than for optically observedhigh-redshift galaxy samples. Incorporating results from the 3D-HST andUltraVISTA surveys we also obtained a more accurate calibration of the sourceredshift distribution than previously achieved for similar optical weak lensingdata sets. Here we studied the extremely massive galaxy clusterRCS2$J$232727.7$-$020437 (\mbox{$z=0.699$}), combining deep VLT/\mbox{HAWK-I}$K_\mathrm{s}$ images (point spread function with a 0\farcs35 full width athalf maximum) with LBT/LBC photometry. The resulting weak lensing massreconstruction suggests that the cluster consists of a single overdensity,which is detected with a peak significance of $10.1\sigma$. We constrained thecluster mass to \mbox{$M_\mathrm{200c}/(10^{15} \mathrm{M}_\odot)=2.06^{+0.28}_{-0.26}(\mathrm{stat.})\pm 0.12 (\mathrm{sys.})$} assuming aspherical Navarro, Frenk \& White model and simulation-based priors on theconcentration, making it one of the most massive galaxy clusters known in the\mbox{$z\gtrsim 0.7$} Universe. We also cross-checked the HAWK-I measurementsthrough an analysis of overlapping HST/ACS images, yielding fully consistentestimates of the lensing signal.

astronomy and astrophysics

Precise weak lensing constraints from deep high-resolution  $K_\mathrm{s}$ images: VLT/HAWK-I analysis of the super-massive galaxy  cluster RCS2$J$232727.7$-$020437 at $z=0.70$