@misc{10481/71434, year = {2021}, month = {8}, url = {http://hdl.handle.net/10481/71434}, abstract = {Context. The properties of galaxies at redshift z>6 hold the key to our understanding of the early stages of galaxy evolution and can potentially identify the sources of the ultraviolet radiation that give rise to the epoch of reionisation. The far-infrared cooling line of [C II] at 158 mu m is known to be bright and correlate with the star formation rate (SFR) of low-redshift galaxies, and hence is also suggested to be an important tracer of star formation and interstellar medium properties for very high-redshift galaxies. Aims. With the aim to study the interstellar medium properties of gravitationally lensed galaxies at z>6, we search for [C II] and thermal dust emission in a sample of 52 > 6 galaxies observed by the ALMA Lensing Cluster Survey. Methods. We perform our analysis using LINESTACKER, stacking both [C II] and continuum emission. The target sample is selected from multiple catalogues, and the sample galaxies have spectroscopic redshift or low-uncertainty photometric redshifts (sigma(z)<0.02) in nine galaxy clusters. Source properties of the target galaxies are either extracted from the literature or computed using spectral energy distribution fitting. Both weighted-average and median stacking are used, on both the full sample and three sub-samples. Results. Our analyses find no detection of either [C II] or continuum. An upper limit on L-[CII] is derived, implying that [C II] remains marginally consistent for low-SFR z>6 galaxies but likely is under-luminous compared to the local L-[CII]-SFR relationship. We discuss potential biases and possible physical effects that may be the cause of the non-detection. Further, the upper limit on the dust continuum implies that less than half of the star formation is obscured.}, organization = {Swedish Research Council}, organization = {European Commission 2015-05580}, organization = {Knut & Alice Wallenberg Foundation}, organization = {Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research (KAKENHI) JP17H06130}, organization = {NAOJ ALMA Scientific Research Grant 2017-06B}, organization = {ANID grants CATA-Basal AFB-170002}, organization = {Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1190818 1200495}, organization = {Millennium Science Initiative ICN12_009}, organization = {Beatriz Galindo senior fellowship from the Ministry of Science and Innovation BG20/00224}, organization = {Villum Fonden research grant 13160}, organization = {Danmarks Grundforskningsfond 140}, organization = {Carlsberg Foundation CF18-0388}, organization = {Ministry of Science, Technology and Space (MOST), Israel}, publisher = {EDP Sciences}, keywords = {Galaxies: formation}, keywords = {Galaxies: statistics}, keywords = {Galaxies: high-redshift}, keywords = {Radio lines: galaxies}, keywords = {Galaxies: evolution}, keywords = {Galaxies: star formation}, title = {ALMA Lensing Cluster Survey: A spectral stacking analysis of [C II] in lensed z similar to 6 galaxies}, doi = {10.1051/0004-6361/202140878}, author = {Jolly, Jean-Baptiste and Espada Fernández, Daniel}, }