Quasar Absorption Lines at High Redshift: Through a Glass Darkly
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Transcript of Quasar Absorption Lines at High Redshift: Through a Glass Darkly
Quasar Absorption Lines at High Redshift:
Through a Glass Darkly
Quasar Absorption Lines at High Redshift:
Through a Glass Darkly
Steve Furlanetto
Caltech
March 18, 2005
Steve Furlanetto
Caltech
March 18, 2005Collaborators: L. Hernquist, A. Loeb,
S.P. Oh, M. Zaldarriaga
The Ly Forest at High Redshifts
The Ly Forest at High Redshifts
Ly forest saturates at z~6!
What have QSO spectra taught us about reionization?
What can we pull out of QSO spectra at z>6? Transmission spikes in
Lyman-series Metal absorption lines
Ly forest saturates at z~6!
What have QSO spectra taught us about reionization?
What can we pull out of QSO spectra at z>6? Transmission spikes in
Lyman-series Metal absorption lines
Becker et al. (2001)
€
τGP ≈ 6x105 xHI
1+ z
10
⎛
⎝ ⎜
⎞
⎠ ⎟3 / 2
SDSS QuasarsSDSS Quasars
SDSS J1030 (z=6.28) No flux for z=6.2-5.98
in Ly or Ly
τ>9.9 (2 mean effective value)
SDSS J1030 (z=6.28) No flux for z=6.2-5.98
in Ly or Ly
τ>9.9 (2 mean effective value)White et al. (2003)
€
τGP ≈ 6x105 xHI
1+ z
10
⎛
⎝ ⎜
⎞
⎠ ⎟3 / 2
€
τ
τ
=fα λαfβ λ β
= 6.24
€
τ
τ
=fα λαfβ λ β
= 6.24
J1030: Mean PropertiesJ1030: Mean Properties
Measured τ +IGM model estimate of ionization rate (assuming uniform)
Appears to change more rapidly at z=6
Difficult to constrain xHI because only probes deep voids
End of reionization? Caveat: poor statistics!
(Paschos & Norman 2004)
Measured τ +IGM model estimate of ionization rate (assuming uniform)
Appears to change more rapidly at z=6
Difficult to constrain xHI because only probes deep voids
End of reionization? Caveat: poor statistics!
(Paschos & Norman 2004)
Fan et al. (2001)
When integrating over large path length, must include cosmic web Transmission samples
unusually underdense voids
Requires model for density distribution!
Extremely difficult to measure xHI!
Different lines sample different densities
When integrating over large path length, must include cosmic web Transmission samples
unusually underdense voids
Requires model for density distribution!
Extremely difficult to measure xHI!
Different lines sample different densities
Lyman-series Optical DepthsLyman-series Optical DepthsQuasar
Observer
Filament
Visible in Ly
Visible in Ly
Lyman-series Optical DepthsLyman-series Optical Depths
When integrating over large path length, must include cosmic web Transmission samples
unusually underdense voids
Requires model for density distribution!
Extremely difficult to measure xHI!
Different lines sample different densities
When integrating over large path length, must include cosmic web Transmission samples
unusually underdense voids
Requires model for density distribution!
Extremely difficult to measure xHI!
Different lines sample different densities
Oh & Furlanetto (2005)
SDSS QuasarsSDSS Quasars
SDSS J1148 (z=6.42) Transmission spikes in
Ly, Ly troughs Residual flux
elsewhere CIV absorber at z=5
Ly emission lines (w/in 1000 km/s)?
Faint continuum?
SDSS J1148 (z=6.42) Transmission spikes in
Ly, Ly troughs Residual flux
elsewhere CIV absorber at z=5
Ly emission lines (w/in 1000 km/s)?
Faint continuum? White et al. (2003)
The Case Against AnInterloper: Residual Flux
The Case Against AnInterloper: Residual Flux
Transmission spikes abruptly stop at z=6.33 for Ly (Oh & Furlanetto 2005)
No continuum break past Ly for z=5 galaxy (Oh & Furlanetto 2005)
Transmission spikes abruptly stop at z=6.33 for Ly (Oh & Furlanetto 2005)
No continuum break past Ly for z=5 galaxy (Oh & Furlanetto 2005)
White et al. (2003)
Residual flux
(5)
Flu
x
Ly atz=5
The IGM Toward J1148+5251The IGM Toward J1148+5251
Residual flux originates at quasar (Oh & Furlanetto 2005) Allows measurement of τ < 15.4 (2), likely τ~7-11, at z=6.18-6.32 (uncertainty
is in IGM density model) IGM is still highly ionized!
SDSS J1030+0524 requires >9.9 (2 ) Difference stronger where transmission spikes appear Large cosmic variance in reionization!
Residual flux originates at quasar (Oh & Furlanetto 2005) Allows measurement of τ < 15.4 (2), likely τ~7-11, at z=6.18-6.32 (uncertainty
is in IGM density model) IGM is still highly ionized!
SDSS J1030+0524 requires >9.9 (2 ) Difference stronger where transmission spikes appear Large cosmic variance in reionization!
White et al. (2003)
Ly atz=6.33Residual
flux (5)
Flu
x
Ly atz=5
The Topology of ReionizationThe Topology of Reionization
Simple semi-analytic models treat HII regions around individual galaxies
Simulations show clustering drives evolution!
Simple semi-analytic models treat HII regions around individual galaxies
Simulations show clustering drives evolution!
Sokasian et al. (2003)
z=8.74z=8.74
z=7.24z=7.24
13 comoving Mpc13 comoving Mpc
Bubble SizesBubble Sizes
SF, MZ, LH (2004a)SF, MZ, LH (2004a)
xH=0.96
xH=0.70
xH=0.25
Bubble Sizes: How Big?Bubble Sizes: How Big?
For bubble to grow, ionizing photons must reach bubble wall
Mean free path depends on density structure of IGM (xH ~ 2)
Limit kicks in when R>10-30 Mpc (Furlanetto & Oh, in prep)
For bubble to grow, ionizing photons must reach bubble wall
Mean free path depends on density structure of IGM (xH ~ 2)
Limit kicks in when R>10-30 Mpc (Furlanetto & Oh, in prep)
QSO SpectraQSO Spectra
What are these transmission spikes? Post-reionization features? Voids? Bubbles?
What are these transmission spikes? Post-reionization features? Voids? Bubbles?
White et al. (2003)
Flu
x
Transmission SpikesTransmission Spikes
For transmission: Must eliminate resonant
absorption: pass close to ionizing source
Must eliminate damping wing absorption: pass through large HII region
For isolated galaxies, NO features before reionization (Barkana 2002)
For transmission: Must eliminate resonant
absorption: pass close to ionizing source
Must eliminate damping wing absorption: pass through large HII region
For isolated galaxies, NO features before reionization (Barkana 2002) IGM HI
QSO
QSO
QSO Absorption SpectraQSO Absorption Spectra
Include clustering of sources: eliminate damping wing absorption
Curves have xH=(0.1,0.15,0.2,0.25) at z=6.1
Simple model: Includes inhomogeneous IGM Naïve distribution of sources
within bubbles No recombinations
Can we probe mid/late stages of reionization with QSO/GRB spectra?
Include clustering of sources: eliminate damping wing absorption
Curves have xH=(0.1,0.15,0.2,0.25) at z=6.1
Simple model: Includes inhomogeneous IGM Naïve distribution of sources
within bubbles No recombinations
Can we probe mid/late stages of reionization with QSO/GRB spectra?
SF, LH, MZ (2004)
ObservedFeature
Studying the IGM StructureStudying the IGM Structure
Mean free path ultimately constrained by dense neutral blobs (?)
Left to right: max mfp=(10, 20, 30, 60, 600) comoving Mpc (all at xi=0.96)
Are we interpreting the tail end of reionization properly?
Mean free path ultimately constrained by dense neutral blobs (?)
Left to right: max mfp=(10, 20, 30, 60, 600) comoving Mpc (all at xi=0.96)
Are we interpreting the tail end of reionization properly?
SF, SPO (in prep)
Complex ReionizationComplex Reionization
WMAP: τ~0.17; reionization begins early SDSS: reionization ends at z=6 Reconcile through complicated source physics: Feedback!, e.g.
Photoionization Minihalos Metal Enrichment
WMAP: τ~0.17; reionization begins early SDSS: reionization ends at z=6 Reconcile through complicated source physics: Feedback!, e.g.
Photoionization Minihalos Metal Enrichment
Wyithe & Loeb (2003)
Complex Reionization:Metal Enrichment
Complex Reionization:Metal Enrichment
Ejection by supernova winds is most likely mechanism
Regulates transition from Pop III (massive?) star formation to Pop II
Complex and extended Highly inhomogeneous New galaxies form Pop III
stars, even late (?) Extended no sharp features
in reionization Extremely uncertain timing and
extent
Ejection by supernova winds is most likely mechanism
Regulates transition from Pop III (massive?) star formation to Pop II
Complex and extended Highly inhomogeneous New galaxies form Pop III
stars, even late (?) Extended no sharp features
in reionization Extremely uncertain timing and
extent
SF, AL (2005)
Increasing Wind Efficiency
Reionization
Metal Absorption LinesMetal Absorption Lines
(1+zs)Ly (1+zs)metal
SDSS collaboration
Can probe Ly/metal< (1+z)/(1+zs) < 1
Metal Absorption LinesMetal Absorption Lines
Important lines: Most abundant elements produced by Type II SNe: C
(YCSN=0.1 Msun), O (0.5 Msun), Si (0.06 Msun), Fe
(0.07 Msun) Most abundant elements produced by VMS SNe: C
(YCSN=4.1 Msun), O (44 Msun), Si (16 Msun), Fe (6.4
Msun) Ionization states determined by radiation background
and nearby galaxy
CII, OI, SiII, FeII for neutral medium CIV, SiIV for ionized medium
Important lines: Most abundant elements produced by Type II SNe: C
(YCSN=0.1 Msun), O (0.5 Msun), Si (0.06 Msun), Fe
(0.07 Msun) Most abundant elements produced by VMS SNe: C
(YCSN=4.1 Msun), O (44 Msun), Si (16 Msun), Fe (6.4
Msun) Ionization states determined by radiation background
and nearby galaxy
CII, OI, SiII, FeII for neutral medium CIV, SiIV for ionized medium
MethodologyMethodology
One wind bubble per halo Star formation history from extended Press-Schechter
Mechanical Luminosity provided by SN rate (and hence SFR)
Use thin-shell approximation (Tegmark et al. 1993) All mass confined to spherical thin shell (no fragmentation) Sweeps up all IGM mass Driving force is hot bubble interior
Consider low-ionization states in spherical shells Free parameters: f*, ESN, IMF, fw (and others)
One wind bubble per halo Star formation history from extended Press-Schechter
Mechanical Luminosity provided by SN rate (and hence SFR)
Use thin-shell approximation (Tegmark et al. 1993) All mass confined to spherical thin shell (no fragmentation) Sweeps up all IGM mass Driving force is hot bubble interior
Consider low-ionization states in spherical shells Free parameters: f*, ESN, IMF, fw (and others)
Wind Characteristics: Shell RadiusWind Characteristics: Shell Radius
Points: Monte Carlo model
Solid line: Halo virial radius
R ~ E1/3 (at constant mass)
R ~ M1/5 (at constant f*)
Points: Monte Carlo model
Solid line: Halo virial radius
R ~ E1/3 (at constant mass)
R ~ M1/5 (at constant f*)
SF, AL (2003)
Wind Characteristics: OI Equivalent Width
Wind Characteristics: OI Equivalent Width
Crosses: z=20 Dashes: z=16 Triangles: z=12 Points: z=8 W ~ M/R2 ~ M3/5
Strongest absorbers surround largest galaxies
Crosses: z=20 Dashes: z=16 Triangles: z=12 Points: z=8 W ~ M/R2 ~ M3/5
Strongest absorbers surround largest galaxies
SF, AL (2003)
Absorption StatisticsAbsorption Statistics
Scalo IMF, f*=0.1 OI 1302 is shown One absorption line
per wind (no fragmentation)
Wtot depends on f*, shape depends on fw
Q~(10-4,10-3,0.01,0.1)
Scalo IMF, f*=0.1 OI 1302 is shown One absorption line
per wind (no fragmentation)
Wtot depends on f*, shape depends on fw
Q~(10-4,10-3,0.01,0.1)
z=20
z=16
z=12
z=8
SF, AL (2003)
What Can We Learn?What Can We Learn?
z=8,f*=0.1 Net absorption similar for low,
high-ionization states Reveals enrichment patterns,
ionizing background (+clumping)
Hot gas will remain invisible: OVI < Ly
Identifying lines may be a challenge Doublets straightforward Others require several lines
together? And distinguish from noise!
z=8,f*=0.1 Net absorption similar for low,
high-ionization states Reveals enrichment patterns,
ionizing background (+clumping)
Hot gas will remain invisible: OVI < Ly
Identifying lines may be a challenge Doublets straightforward Others require several lines
together? And distinguish from noise!
SF, AL (2003)
What Can We Learn?What Can We Learn?
Some models require “prompt enrichment” by VMS stars in minihalos: Q~0.1-1 at high redshifts
Expect significant absorption, e.g. CII: τ~0.16 (Z/10-2.5 Zsun) (1+z/7)3/2
Actually expect forest of features from density structure
Do background sources exist?
Some models require “prompt enrichment” by VMS stars in minihalos: Q~0.1-1 at high redshifts
Expect significant absorption, e.g. CII: τ~0.16 (Z/10-2.5 Zsun) (1+z/7)3/2
Actually expect forest of features from density structure
Do background sources exist?
Metal Lines and ReionizationMetal Lines and Reionization
OI/HI in tight charge-exchange equilibrium τ~0.14 (Z/10-2.5 Zsun) for
equivalent GP trough
Dense regions enriched first but ionized last “forest” of (unsaturated) OI lines near reionization
Stretch into near-IR: sky lines difficult!
OI/HI in tight charge-exchange equilibrium τ~0.14 (Z/10-2.5 Zsun) for
equivalent GP trough
Dense regions enriched first but ionized last “forest” of (unsaturated) OI lines near reionization
Stretch into near-IR: sky lines difficult!
Oh (2002)
SummarySummary
SDSS quasars indicate something dramatic happens at z~6, but its nature unclear Huge cosmic variance between two lines of sight!
Models of reionization suggest variations in on large scales Allows transmission in QSO spectra when xHI<0.25: study transition
from “bubble-dominated” to “web-dominated” universe Other probes of topology: 21 cm emission, kSZ effect, Ly galaxies
Metal lines with >Ly must appear beyond reionization! Trace course of enrichment (crucial piece of extended reionization) “OI forest” at tail end of reionization Expectations far from clear: hugely simplified models so far!
SDSS quasars indicate something dramatic happens at z~6, but its nature unclear Huge cosmic variance between two lines of sight!
Models of reionization suggest variations in on large scales Allows transmission in QSO spectra when xHI<0.25: study transition
from “bubble-dominated” to “web-dominated” universe Other probes of topology: 21 cm emission, kSZ effect, Ly galaxies
Metal lines with >Ly must appear beyond reionization! Trace course of enrichment (crucial piece of extended reionization) “OI forest” at tail end of reionization Expectations far from clear: hugely simplified models so far!
The Case Against anInterloper: Transmission Spikes
The Case Against anInterloper: Transmission Spikes If emission lines from
intervening galaxy, should be extended source (>1 arcsec)
White et al. (2005) observed with narrowband ACS filter: point source!
z=5 galaxy does help clear Ly forest
If emission lines from intervening galaxy, should be extended source (>1 arcsec)
White et al. (2005) observed with narrowband ACS filter: point source!
z=5 galaxy does help clear Ly forest
SDSS Quasars: “Proximity Zones”SDSS Quasars: “Proximity Zones”
Ly/Ly flux ratios J1030 has region with Ly
transmission but no Ly Requires smooth damping
wing component xHI>0.1? (Mesinger & Haiman 2004)
Does not appear in J1148 QSO redshift + edge of
transmission measure size of HII region? Luminosity + lifetime
xHI>0.1 (Wyithe & Loeb 2004) But see Yu & Lu (2004)
Ly/Ly flux ratios J1030 has region with Ly
transmission but no Ly Requires smooth damping
wing component xHI>0.1? (Mesinger & Haiman 2004)
Does not appear in J1148 QSO redshift + edge of
transmission measure size of HII region? Luminosity + lifetime
xHI>0.1 (Wyithe & Loeb 2004) But see Yu & Lu (2004)
White et al. (2003)
The Topology of ReionizationThe Topology of Reionization
Simple ansatz:
mion = mgal
= f* fesc N/b / (1+nrec)
Then condition for a region to be fully ionized is
fcoll > -1
Simple ansatz:
mion = mgal
= f* fesc N/b / (1+nrec)
Then condition for a region to be fully ionized is
fcoll > -1
Neutral IGM
Ionized IGM
Galaxy
The Topology of ReionizationThe Topology of Reionization
Simple ansatz:
mion = mgal
= f* fesc N/b / (1+nrec)
Then condition for a region to be fully ionized is
fcoll > -1
Simple ansatz:
mion = mgal
= f* fesc N/b / (1+nrec)
Then condition for a region to be fully ionized is
fcoll > -1
Neutral IGM
Ionized IGM
Galaxy
The Topology of ReionizationThe Topology of Reionization
Simple ansatz:
mion = mgal
= f* fesc N/b / (1+nrec)
Then condition for a region to be fully ionized is
fcoll > -1
Simple ansatz:
mion = mgal
= f* fesc N/b / (1+nrec)
Then condition for a region to be fully ionized is
fcoll > -1
Neutral IGM
Ionized IGM?
Galaxy
The Topology of ReionizationThe Topology of Reionization
Simple ansatz:
mion = mgal
= f* fesc N/b / (1+nrec) Then condition for a
region to be fully ionized is
fcoll > -1
Can construct an analog of Press-Schechter mass function = mass function of ionized regions
Simple ansatz:
mion = mgal
= f* fesc N/b / (1+nrec) Then condition for a
region to be fully ionized is
fcoll > -1
Can construct an analog of Press-Schechter mass function = mass function of ionized regions
Neutral IGM
Ionized IGM
Galaxy
Bubble Sizes: Why?Bubble Sizes: Why?
Mostly independent of redshift at fixed xH
Depends primarily on the bias of ionizing sources
Solid lines: f*=const
Dashed lines: f*~m2/3
Mostly independent of redshift at fixed xH
Depends primarily on the bias of ionizing sources
Solid lines: f*=const
Dashed lines: f*~m2/3
xH=0.8
xH=0.25
SF, MZ, LH (in prep)SF, MZ, LH (in prep)
Metal Pollution: Filling FactorMetal Pollution: Filling Factor
Different curves show f*=0.01, 0.1, 0.5, from bottom to top
Solid: H2 cooling Dotted: Atomic
cooling Ignores galaxy
clustering!
Different curves show f*=0.01, 0.1, 0.5, from bottom to top
Solid: H2 cooling Dotted: Atomic
cooling Ignores galaxy
clustering!
FL03
FL03
What Can We Learn?What Can We Learn?
z=8 Solid: f*=0.5, f*=0.1,
f*=0.01 Dashed: vary fraction
of SN energy in wind
z=8 Solid: f*=0.5, f*=0.1,
f*=0.01 Dashed: vary fraction
of SN energy in wind