SLIDE 1
LAES POWERED BY AGN AND THEIR IMPACTS ON COSMIC REIONIZATION
SUNGHYE BAEK (SNS, ITALY)
COLLABORATION WITH ANDREA FERRARA SKA IN EAST ASIA 2013 NAGOYA UNIVERSITY 5-7 JUNE 2013
2013 MNRAS 432L 6B
SLIDE 2 THE 21 CM SIGNAL AND THE 21 CM SIGNAL AND REIONIZATION REIONIZATION
MOST PROMISING PROBE OF THE DARK AGES AND REIONIZATION SIGNAL REDSHIFTED TO METER WAVE (50-200 MHZ), DETECTABLE WITH SKA THE INTENSITY OF THE 21CM DEPENDS ON THE TEMPERATURE OF THE IGM : WE CAN CONSTRAIN SOURCE PROPERTIES (X-RAYS) USING THE 21 CM POWER SPECTRUM
- X-RAYS HEATING → INCREASE GAS TEMPERATURE (IGM) →REDUCE THE
INTENSITY OF THE 21 CM SIGNAL
SLIDE 3
X-RAYS AND THE IGM X-RAYS AND THE IGM TEMPERATURE TEMPERATURE
BAEK+2010
SLIDE 4
POWER SPECTRUM OF POWER SPECTRUM OF ΔT TB
B BAEK+2010
SLIDE 5
X-RAY SOURCE CANDIDATE AT X-RAY SOURCE CANDIDATE AT HIGH-Z HIGH-Z
QSO : THE MOST RECENT RECORD AT Z=7.1 HOSTING 109 MSOL BH THEIR PROGENITORS Z > 7 : AGN HOSTING MINI OR INTERMEDIATE BH WHERE X-RAY INTENSITY UNDER DETECTION LIMIT THE ROLE OF MINI(INTERMEDIATE) BH IN ACTIVE NUCLEUS GALAXY : ALTERNATIVE SOURCE FOR LYMAN ALPHA? WHAT IS THE PROPERTIES OF SUCH LAE POWERED BY AGN WITH RESPECT TO THE ONE POWERED BY STARBURST?
SLIDE 6
LYMAN APHA EMITTERS LYMAN APHA EMITTERS
A PROMINENT LYα (N=2 →N=1 : 1216 Å) LINE EMITTING GALAXIES (EW ≥ 20 Å) HIGH REDSHIFT, STARBURST GALAXIES, HIGH HI DENSITY (Z≅2-7) STAR FORMATION → IONIZING UV → RECOMBINATION → EMITTING LYα SOURCES OF REIONIZATION
SLIDE 7
ORIGINS OF LYMAN PHOTON ORIGINS OF LYMAN PHOTON
RECOMBINATION IN THE IONIZED GAS STAR FORMING HIGH DENSE REGION STRONG UV FIELD, SHORT RECOMBINATION TIME VERY EFFICIENT PROCESS EXCITATION - DEEXCITATION IN THE NEUTRAL GAS STELLAR WIND VIA COOLING (LYMAN ALPHA BLOB) X-RAYS
SLIDE 8
MOTIVATION MOTIVATION
Galaxies at high redshift (z>6) are compact and contains plenty of neutral gas. When AGN in LAE is faint (X-rays flux under detection limit) and obscured (no broaden emission), How can we distinguish and identify them from LAE powered by starburst?
SLIDE 9 LAE WITH AGN LAE WITH AGN
Shibuya et al. 2012
Variable photometry Shibuya et al. 2012 at z~7.3 Temporal luminosity enhancement associated with a QSO, an AGN, or SN
Gawiser et al. 2006 at z~3 Zheng et al. 2010 at z~4.5 Broaden emission line Ouchi et al. 2008 at z~3-4, 800 candidates 1 % contains AGN Brightest LAEs with Log(Lα) > 43.4-43.6 erg s-1
SLIDE 10 10 cMpc/h
Hydrodynamics Gadget2 2 X 5123 DM and baryon DM : 6.68 X 105 Msol Baryon : 1.32 X 105 Msol
and IGM to modeling LAE at z=6.6
UV, X-ray RT with LICORICE A Point source at the center
Source from every cell where Log(Lα) > 37 [erg s-1]
NUMERICAL SIMULATION
SLIDE 11
STARBURST99 : 0.02 Zsol, Salpeter IMF, 1-100 Msol cut off Continuous SFR : 10 Msol/yr
- 2. The Compton thick AGN (Shang et al. 2011)
UV and X-rays confined in a cone with opening θ=45°
Isotropically emitted for X-rays 100eV < hν < 500eV
X-rays
AGN composite spectra
˙ Q = 3 × 1054s−1
Normalized to have the same photoionization rate
3 MODELS - DIFFERENT SED 3 MODELS - DIFFERENT SED
A halo with Mh=1.17X1011 Msol
SLIDE 12 TOTAL INTRINSIC LYA TOTAL INTRINSIC LYA
X-rays Recombination
Lya production : X-rays ➘ ➘ with time Recombination ➚ ➚ with time Early : X-ray dominated Later : Recombination dominated
★
SLIDE 13 Lyα radiative transfer
Neutral fraction Lyα production Lyα Surface Brightness
60 pkpc/h UV, X-rays RT Lyα RT
1st post processing 2nd post processing
SLIDE 14
Nature of LAE powered by AGN
SLIDE 15
- 1. Evolution of skewness Sw
Early phase Later phase
SLIDE 16 Lower skewness
Ouchi et al. 2008
z~5.7
SLIDE 17
- 2. Evolution of the SB profile (the SB map)
Early phase or X-ray effect dominates Later phase or recombination dominates
SLIDE 18 Skewness vs. FWHM of SB
Parametrized curves with time t = 0.02, 0.04, 0.06, 0.08, 1.00 Myr from left to right The shaded area denotes AGN-powered LAE identification criterion Sw < 0 and FWHM ≥1.5”
SLIDE 19 Summary
Alternative X-ray/Lya source for high-z (z>6) High redshift (z>6) LAE probably contains obscured and less powerful AGN For given Q, X-rays can boost Lyα luminosity with several
- rders when there is plenty of neutral gas
(e.g. when AGN just turns on or large amount of accreting gas) Nature of LAE powered by AGN The lower skewness Sw < 0 Extended SB profile, having FWHM greater than FWHM
- f PSF(seeing size) FWHM ≥1.5”
