Oral Presentation

Probing large-scale structures with emission-line galaxies selected from HSC narrow-band data

Author(s): Masao Hayashi (NAOJ)

Presenter: Masao Hayashi (National Astronomical Observatory of Japan)

Narrow-band (NB) imaging allows us to select emission-line galaxies with SFR larger than a certain limit at specific redshifts. The HSC-SSP PDR1 provides us with the NB816 data over 5.7 deg^2 and the NB921 data over 16.2 deg^2, which are one of the widest NB imaging data. We constructed the large samples of 8054 Halpha emitters at z~0.25 and 0.40, 8656 [OIII] emitters at z~0.63 and 0.84, and 16877 [OII] emitters at z ~ 1.19 and 1.47. Thanks to the narrow redshift range, the projection effect along the depth direction is not significant at each redshift. Therefore, the unbiased wide-field survey of star-forming galaxies reveals large-scale structures on scales out to about 50 comoving Mpc including galaxy clusters, filaments, and voids. In the HSC-SSP PDR2 released on May 2019, the coverage of NB data will be much wider: NB816 and NB921 data over ~21 deg^2, respectively, which makes the HSC-SSP NB data more unique. Also, we have conducted follow-up spectroscopy of the NB emitters. We observed more than one thousand NB emitters in the UD-SXDS and D-DEEP2-3 fields using 2dF+AAOmega at the 4m-class AAT which has a field-of-view of 2 degrees and 400 fibers. The spectroscopy confirms the NB emitters at a high success rate and thus demonstrates that the NB emitters are good targets to investigate the star-forming galaxies at various environments at different redshifts. The combination of HSC imaging and AAOmega follow-up spectroscopy is a pilot study for the synergy of HSC and PFS. Therefore, I would like to present the update of the emitter catalogs, the results on the NB emitters from both the HSC-SSP imaging and the follow-up spectroscopy. Then, I would like to discuss the expansion of the studies with HSC and PFS.