Cosmic Dawn at High Latitudes Conference

Galaxies as Agents of Cosmic Reionization: Insights from the EIGER Survey

24 Jun 2024, 14:45

15m

Beijer auditorium (Swedish Royal Academy of Sciences)

Session 2

Speaker

Daichi Kashino (NAOJ)

Description

We present the results from the EIGER survey, conducting JWST/NIRCam WFSS surveys in the fields of luminous quasars at $z\ge 6$. Our analysis includes observations from five of the six designated quasar fields, leading to the identification of approximately 750 [OIII]-emitting galaxies with spectroscopic confirmation across a redshift span of $z=5.3$-–7.0. By examining both the spatial distribution of these galaxies and the spectral data from the associated quasars, we have pinpointed specific instances of co-location of galaxies and ionized regions, as traced by Lyman-alpha and/or Lyman-beta transmission spikes. This correlation serves as direct proof of galaxies facilitating localized reionization events. Additionally, our findings reveal that, at lower redshifts ($z<5.7$), approaching the end of reionization, transmission is more suppressed nearer to galaxies within $\sim 10$ cMpc, likely reflecting overdensity around them. Conversely, at higher redshifts, excess transmission is observed $\sim 7$ cMpc away from galaxies. All these observations align with the 'inside-out' scenario that reionization occurred from overdense regions where galaxies began forming earlier.

Presentation materials

kashino.pdf