%0 Generic %1 shimakawa2017direct %A Shimakawa, Rhythm %A Kodama, Tadayuki %A Hayashi, Masao %A Tanaka, Ichi %A Matsuda, Yuichi %A Kashikawa, Nobunari %A Shibuya, Takatoshi %A Tadaki, Ken-ichi %A Koyama, Yusei %A Suzuki, Tomoko L. %A Yamamoto, Moegi %D 2017 %K Lya filament overdensity %T Direct evidence for Ly$\alpha$ depletion in the protocluster core %U http://arxiv.org/abs/1702.00100 %X We have carried out a panoramic Ly$\alpha$ narrowband imaging with Suprime-Cam on Subaru towards the known protocluster USS1558--003 at $z=2.53$. Our previous narrowband imaging at near-infrared has identified multiple dense groups of H$\alpha$ emitters (HAEs) within the protocluster. We have now identified the large-scale structures across a $\sim$50 comoving Mpc scale traced by Ly$\alpha$ emitters (LAEs) in which the protocluster traced by the HAEs is embedded. On a smaller scale, however, there are remarkably few LAEs in the regions of HAE overdensities. Moreover, the stacking analyses of the images show that HAEs in higher-density regions show systematically lower escape fractions of Ly$\alpha$ photons than those of HAEs in lower-density regions. These phenomena may be driven by the extra depletion of Ly$\alpha$ emission lines along our line of sight by more intervening cold circumgalactic/intergalactic medium and/or dust existing in the dense core. We also caution that all the past high-$z$ protocluster surveys using LAEs as the tracers would have largely missed galaxies in the very dense cores of the protoclusters where we would expect to see any early environmental effects.

@misc{shimakawa2017direct, abstract = {We have carried out a panoramic Ly$\alpha$ narrowband imaging with Suprime-Cam on Subaru towards the known protocluster USS1558--003 at $z=2.53$. Our previous narrowband imaging at near-infrared has identified multiple dense groups of H$\alpha$ emitters (HAEs) within the protocluster. We have now identified the large-scale structures across a $\sim$50 comoving Mpc scale traced by Ly$\alpha$ emitters (LAEs) in which the protocluster traced by the HAEs is embedded. On a smaller scale, however, there are remarkably few LAEs in the regions of HAE overdensities. Moreover, the stacking analyses of the images show that HAEs in higher-density regions show systematically lower escape fractions of Ly$\alpha$ photons than those of HAEs in lower-density regions. These phenomena may be driven by the extra depletion of Ly$\alpha$ emission lines along our line of sight by more intervening cold circumgalactic/intergalactic medium and/or dust existing in the dense core. We also caution that all the past high-$z$ protocluster surveys using LAEs as the tracers would have largely missed galaxies in the very dense cores of the protoclusters where we would expect to see any early environmental effects.}, added-at = {2017-02-02T11:22:33.000+0100}, author = {Shimakawa, Rhythm and Kodama, Tadayuki and Hayashi, Masao and Tanaka, Ichi and Matsuda, Yuichi and Kashikawa, Nobunari and Shibuya, Takatoshi and Tadaki, Ken-ichi and Koyama, Yusei and Suzuki, Tomoko L. and Yamamoto, Moegi}, biburl = {https://www.bibsonomy.org/bibtex/209baef659617afcc80c0488a38d3adc9/miki}, description = {[1702.00100] Direct evidence for Ly$\alpha$ depletion in the protocluster core}, interhash = {efa91bec309c0ecc31c6de7defb72375}, intrahash = {09baef659617afcc80c0488a38d3adc9}, keywords = {Lya filament overdensity}, note = {cite arxiv:1702.00100Comment: 6 pages, 4 figures, accepted for publication in MNRAS Letter}, timestamp = {2017-02-02T11:22:33.000+0100}, title = {Direct evidence for Ly$\alpha$ depletion in the protocluster core}, url = {http://arxiv.org/abs/1702.00100}, year = 2017 }