Reaching for the Edge I: Probing the Outskirts of Massive Galaxies with HSC, DECaLS, SDSS, and Dragonfly

Abstract

The outer light (stellar halos) of massive galaxies has recently emerged as a possible low scatter tracer of dark matter halo mass. To test the robustness of outer light measurements across different data sets, we compare the surface brightness profiles of massive galaxies using four independent data sets: the Hyper Suprime-Cam survey (HSC), the Dark Energy Camera Legacy Survey (DECaLS), the Sloan Digital Sky Survey (SDSS), and the Dragonfly Wide Field Survey (Dragonfly). We use customized pipelines for HSC and DECaLS to achieve better sky background subtraction. For galaxies at z < 0.05, Dragonfly has the best control of systematics, reaching surface brightness levels of µ r ∼ 30 mag/arcsec 2 . At 0.19 < z < 0.50, HSC can reliably recover surface brightness profiles to µ r ∼ 28.5 mag/arcsec 2 reaching R = 100 − 150 kpc. DECaLS surface brightness profiles show good agreement with HSC but are noisier at large radii. The median profiles of galaxy ensembles in both HSC and DECaLS reach R > 200 kpc without significant bias. At 0.19 < z < 0.50, DECaLS and HSC measurements of the stellar mass contained within 100 kpc agree within 0.05 dex. Finally, we use weak gravitational lensing to show that measurements of outer light with DECaLS at 0.19 < z < 0.50 show a similar promise as HSC as a low scatter proxy of halo mass. The tests and results from this paper represent an important step forward for accurate measurements of the outer light of massive galaxies and demonstrate that outer light measurements from DECam imaging will be a promising method for finding galaxy clusters for DES and DESI.

Dust in Clusters of Galaxies

“…However, Ragusa et al [150] conclude that the ICL colors g − r ∼ 0.7 mag and r − i ∼ 0.4 mag are consistent with the stellar population synthesis of intermediate-mass (M = 10 10 − 10 11 M ) galaxies without clear traces of dust, besides contaminations from Galactic cirrus at λ = 100 µm. It is worth noting that the averaged radial profiles in HCG 86 look similar (although obviously brighter) to the ones inferred for galaxy clusters [151,152], with the floor at µ ∼ 30 mag arcsec −2 strongly contaminated by the Galaxy cirrus [153][154][155]. A clear observational evidence of the virialization can be recognized in the image of the cluster CL0024+17 on Figure 6 obtained at the Large Binocular Telescope (LBT) by Giallongo et al [156]: in the lower panel, a concentration of the ICL toward the apparent cluster center of mass is observable.…”

KMTNet Nearby Galaxy Survey: Overview and Survey Description

“…7. Trujillo et al (2021) Li et al (2021) robustly evaluated the depth of these data and suggested that both HSC and DECaLS can achieve a surface brightness limit of μ r ∼ 28-29 mag arcsec −2 if customized pipelines are applied. 9.…”

The Sphere of Influence of the Bright Central Galaxies in the Diffuse Light of SDSS Clusters

“…Detailed kinematic analysis of the hydrodynamical simulations of cluster formation could be tremendously helpful for providing insight to the growth of the BCG sphere of influence, as well as an indirect check of the physical link between 𝑟 𝑠 and 𝑅 SOI . Observationally, our work can be easily extended to the larger cluster catalogues (Zou et al 2021;Wen & Han 2021;Yang et al 2021) and deeper photometry (Huang et al 2021;Li et al 2021) from current stage-III imaging surveys. Future ground-based and space missions like the LSST, Euclid, Roman, and CSST with even larger cluster samples, deeper photometry, and sharper shear measurements will greatly enhance our capability of seeing cluster formation through the diffuse light.…”