%0 Generic %1 hu2021lymanalpha %A Hu, Weida %A Wang, Junxian %A Infante, Leopoldo %A Rhoads, James E. %A Zheng, Zhen-Ya %A Yang, Huan %A Malhotra, Sangeeta %A Barrientos, L. Felipe %A Jiang, Chunyan %A González-López, Jorge %A Prieto, Gonzalo %A Perez, Lucia A. %A Hibon, Pascale %A Galaz, Gaspar %A Coughlin, Alicia %A Harish, Santosh %A Kong, Xu %A Kang, Wenyong %A Khostovan, Ali Ahmad %A Pharo, John %A Valdes, Francisco %A Wold, Isak %A Walker, Alistair R. %A Zheng, XianZhong %D 2021 %K library %R 10.1038/s41550-020-01291-y %T A Lyman-\alpha protocluster at redshift 6.9 %U http://arxiv.org/abs/2101.10204 %X Protoclusters, the progenitors of the most massive structures in the Universe, have been identified at redshifts of up to 6.6. Besides exploring early structure formation, searching for protoclusters at even higher redshifts is particularly useful to probe the reionization. Here we report the discovery of the protocluster LAGER-z7OD1 at a redshift of 6.93, when the Universe was only 770 million years old and could be experiencing rapid evolution of the neutral hydrogen fraction in the intergalactic medium. The protocluster is identified by an overdensity of 6 times the average galaxy density, and with 21 narrowband selected Lyman-$\alpha$ galaxies, among which 16 have been spectroscopically confirmed. At redshifts similar to or above this record, smaller protogroups with fewer members have been reported. LAGER-z7OD1 shows an elongated shape and consists of two subprotoclusters, which would have merged into one massive cluster with a present-day mass of $3.7 10^15$ solar masses. The total volume of the ionized bubbles generated by its member galaxies is found to be comparable to the volume of the protocluster itself, indicating that we are witnessing the merging of the individual bubbles and that the intergalactic medium within the protocluster is almost fully ionized. LAGER-z7OD1 thus provides a unique natural laboratory to investigate the reionization process.

@misc{hu2021lymanalpha, abstract = {Protoclusters, the progenitors of the most massive structures in the Universe, have been identified at redshifts of up to 6.6. Besides exploring early structure formation, searching for protoclusters at even higher redshifts is particularly useful to probe the reionization. Here we report the discovery of the protocluster LAGER-z7OD1 at a redshift of 6.93, when the Universe was only 770 million years old and could be experiencing rapid evolution of the neutral hydrogen fraction in the intergalactic medium. The protocluster is identified by an overdensity of 6 times the average galaxy density, and with 21 narrowband selected Lyman-$\alpha$ galaxies, among which 16 have been spectroscopically confirmed. At redshifts similar to or above this record, smaller protogroups with fewer members have been reported. LAGER-z7OD1 shows an elongated shape and consists of two subprotoclusters, which would have merged into one massive cluster with a present-day mass of $3.7 \times 10^{15}$ solar masses. The total volume of the ionized bubbles generated by its member galaxies is found to be comparable to the volume of the protocluster itself, indicating that we are witnessing the merging of the individual bubbles and that the intergalactic medium within the protocluster is almost fully ionized. LAGER-z7OD1 thus provides a unique natural laboratory to investigate the reionization process.}, added-at = {2021-01-26T07:45:46.000+0100}, author = {Hu, Weida and Wang, Junxian and Infante, Leopoldo and Rhoads, James E. and Zheng, Zhen-Ya and Yang, Huan and Malhotra, Sangeeta and Barrientos, L. Felipe and Jiang, Chunyan and González-López, Jorge and Prieto, Gonzalo and Perez, Lucia A. and Hibon, Pascale and Galaz, Gaspar and Coughlin, Alicia and Harish, Santosh and Kong, Xu and Kang, Wenyong and Khostovan, Ali Ahmad and Pharo, John and Valdes, Francisco and Wold, Isak and Walker, Alistair R. and Zheng, XianZhong}, biburl = {https://www.bibsonomy.org/bibtex/23b3fbd61d8a1532f33fab113315579b1/gpkulkarni}, description = {A Lyman-{\alpha} protocluster at redshift 6.9}, doi = {10.1038/s41550-020-01291-y}, interhash = {f18df0f09c9f662193bbff0cc417e18d}, intrahash = {3b3fbd61d8a1532f33fab113315579b1}, keywords = {library}, note = {cite arxiv:2101.10204Comment: 9 pages, 5 figures, and 1 table. Accepted by Nature Astronomy}, timestamp = {2021-01-26T07:45:46.000+0100}, title = {A Lyman-{\alpha} protocluster at redshift 6.9}, url = {http://arxiv.org/abs/2101.10204}, year = 2021 }