Reionization by Galaxies and QSOs and the Thermal State of the IGM What drives reionization? Koki Kakiichi MPA with thanks to Luca Graziani, Benedetta Ciardi, Avery Meiksin, Michele Compostella, Marius Eide, Saleem Zaroubi Berlin, July, 2016
Helium reionization Hydrogen reionization What is the role of galaxies & QSOs during reionization?
Theoretically understanding the role of galaxies & QSOs using full RT reionization simulations larger box N-body + post-processing RT (e.g. Dixon+16) Computational resource limit plane spatially adaptive! radiation hydrodynamical simulation (e.g. Pawlik+16, Gnedin 15) spatial resolution Frequency sampling Hydrodynamics + post-processing! multi-frequency RT Important to treat H & He reionization! & thermal structure of the IGM
! Multi-frequency Cosmological Radiative Transfer Simulations study of a high-z QSO environment KK+ QSO + Galaxies Impact of QSO Shapiro&Giroux 87, Meiksin&Madau 93, Miralda- Escude+00, Wythie&Loeb 03, Yu 05, Lidz+07, Datta+12, Feng+13, Keating+15 ~10-100Mpc picture not to scale
Approach: a suite of RT simulations We want!! A reference simulation (observationally-calibrated)!!! +vary the source models & radiative transfer processes!! Understand the physical mechanisms controlling reionization by galaxies and QSOs 50cMpc/h. QSO at z=10 Hydro sim 2x512 3, ~10 7 M GADGET-3 RT sim. 256 3 with CRASH
Approach: a suite of RT simulations We want!! A reference simulation (observationally-calibrated)!!! +vary the source models & radiative transfer processes!! Understand the physical mechanisms controlling reionization by galaxies and QSOs 50cMpc/h. QSO at z=10 Hydro sim 2x512 3, ~10 7 M GADGET-3 RT sim. 256 3 with CRASH fesc -like parameter spectral shape X-ray physics galaxies only { QSO only { Galaxies+QSO {
Approach: a suite of RT simulations We want!! A reference simulation (observationally-calibrated)!!! +vary the source models & radiative transfer processes!! Understand the physical mechanisms controlling reionization by galaxies and QSOs 50cMpc/h. QSO at z=10 Hydro sim 2x512 3, ~10 7 M GADGET-3 RT sim. 256 3 with CRASH fesc -like parameter spectral shape X-ray physics galaxies only { QSO only { { Galaxies+QSO Full reference run
Source models (observation-based) Galaxies Pre-assumed total ionizing photon emissivity from galaxies based on the UV background measurement & high-z galaxy observations +assuming fesc=30% QSO (z=10) c.f. z=7 ULAS J1120+0641 (Mortlock+2011, Bolton+2011) ~10 57 photons/s (MSMBH~10 9 M )
H & He reionization in high-z QSO environment
Full reference run: Multi-frequency (UV+X-rays) RT simulation of reionization driven by galaxies and a QSO Hydrogen reionization Helium reionization QSO 50cMpc red xi~1 green/blue xi~0.1-0.01 gray xi~0
Full reference run: Multi-frequency (UV+X-rays) RT simulation of reionization driven by galaxies and a QSO Hydrogen reionization QSO+galaxies-driven HII region galaxies-driven HII region Helium reionization QSO-dominated HeIII region QSO 50cMpc red xi~1 green/blue xi~0.1-0.01 gray xi~0
He III He II H II What controls the morphology of HII & HeII/HeIII regions? Contributions from the surrounding galaxies around a QSO Galaxies only QSO only Full REF galaxies+qso less more total emissivity from galaxies
He III He II H II What controls the morphology of HII & HeII/HeIII regions? Contributions from the surrounding galaxies around a QSO Galaxies only QSO only Full REF galaxies+qso The collective impact of a QSO & galaxies in H reionization! The unique impact of a QSO on He reionization less more total emissivity from galaxies (see also Datta+ 12; Lidz+ 07)
Why is the contribution from galaxies so important? The total number of ionising photons from galaxies RI integrated ionizing! photon emissivity QSO-galaxy! clustering Morphology of HII regions! Ratio of the QSO luminosity x lifetime (dnion/dt * tq) vs.! the integrated total ionising photons of galaxies around a QSO! since the onset of reionization
So, what does a QSO do to the IGM? Impact of X-rays from a QSO QSO only H II He II! QSO UV+X-ray (with secondary ionization) QSO UV+X-ray (without secondary ionization) QSO UV only He III Tail of partial ionization ahead of I-fronts by X-ray from a QSO.!! The enhancement due to secondary ionization.
How does the morphology of reionization depend on power-law (slope=1.5) QSO only the spectrum of a QSO? power-law + obscuration H II He II He III H II He III Ionization front is broader for a UV-obscured QSO (see also Kramer&Haiman 08; Thomas&Zaroubi 08) because of 1. the presence of X-rays 2. the lack of UV photons power-law power-law+obscuration
How does the morphology of reionization depend on the spectrum of a QSO? Galaxies only Galaxies+QSO Galaxies+obscured QSO He III H II
How does the morphology of reionization depend on the spectrum of a QSO? Galaxies only Galaxies+QSO Galaxies+obscured QSO He III H II
How does the morphology of reionization depend on the spectrum of a QSO? Galaxies only Galaxies+QSO Galaxies+obscured QSO He III H II Morphology of HII regions! Spectral shape of the collective radiation field of galaxies and a QSO driving the I-front (X-ray dominated or UV dominated?)
Thermal structure of the IGM in high-z QSO environment
How reionization by galaxies and QSOs shapes the thermal state of the IGM?
How reionization by galaxies and QSOs shapes the thermal state of the IGM? Galaxies only Galaxies+QSO REF less total emissivity from galaxies more QSO only
How reionization by galaxies and QSOs shapes the thermal state of the IGM? Additional heating by a QSO
How reionization by galaxies and QSOs shapes the thermal state of the IGM? Additional heating by a QSO Pre-existed HII I-front of galaxies QSO HII I-front
How reionization by galaxies and QSOs shapes the thermal state of the IGM? Additional heating by a QSO Pre-existed HeIII I-front of galaxies QSO HeIII I-front
How reionization by galaxies and QSOs shapes the thermal state of the IGM? Additional heating by a QSO Analytic estimate photoionisation heating across I-fronts (e.g. Abel&Haehnelt 97; Meiksin&Tittley 12, also related McQuinn&Upton-Sanderbeck 16)
How reionization by galaxies and QSOs shapes the thermal state of the IGM? Additional heating by a QSO Analytic estimate photoionisation heating across I-fronts (e.g. Abel&Haehnelt 97; Meiksin&Tittley 12, also related McQuinn&Upton-Sanderbeck 16) QSO and galaxies together, nonlinearly, impact the thermal state.! The order of photionization heating by galaxies or QSOs matters!
Observational tests how to constrain the sources of reionization observationally? QSO spectra - spectral hardness of the UV background from metal line ratio? (e.g. Finlator+16) - the thermal structure of the IGM around QSO? (e.g. Bolton+12)! Galaxy survey in a region of 21cm tomography - direct comparison of the HII region size with the ionising photons (inferred from their spectra) of galaxies & QSO (e.g. Beardsley+15)! 3.46cm 3 HeII signal? - direct probe of He reionization at z>6?? (but very weak? McQuinn&Switzer 09, Bagla & Loeb 09)
Observational tests how to constrain the sources of reionization observationally? QSO spectra - spectral hardness of the UV background from metal line ratio? (e.g. Finlator+16) - the thermal structure of the IGM around QSO? (e.g. Bolton+12)! Galaxy survey in a region of 21cm tomography - direct comparison of the HII region size with the ionising photons (inferred from their spectra) of galaxies & QSO (e.g. Beardsley+15)! 3.46cm 3 HeII signal? - direct probe of He reionization at z>6?? (but very weak? McQuinn&Switzer 09, Bagla & Loeb 09)
aside Mukae, Ouchi, KK+(2016) The galaxy-igm relation from COSMOS/UltraVISTA galaxies + BOSS/SDSSIII Lyɑ forest analysis using hydrodynamical simulations of Lyɑ forest Mag.-selected galaxy overdensity preferentially resides in the excess Lyɑ absorption, but with a large scatter (consistency test for the filamentary IGM???)!
Conclusion Multi-frequency RT with galaxies & a QSO:!! The concerted picture of hydrogen and helium reionization driven by galaxies & QSO in high-z QSO environment A unified treatment of H & He reionization Better constraints on the role of galaxies & QSOs (via H, He, T)