Constraining reionization
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Constraining reionization through quasar and gamma ray burst absorption spectra. Simona Gallerani. Astronomical Observatory of Rome. In collaboration with: T. Roy Choudhury, P. Dayal, X. Fan, A. Ferrara, A. Maselli, R. Salvaterra. COSMOLOGICAL REIONIZATION CONFERENCE

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Constraining reionization

through quasar and gamma ray burst absorption spectra

Simona Gallerani

Astronomical Observatory of Rome

In collaboration with:

T. Roy Choudhury, P. Dayal, X. Fan, A. Ferrara, A. Maselli, R. Salvaterra

COSMOLOGICAL REIONIZATION CONFERENCE

Harish-Chandra Research Institute, Allahabad, 16 February 2010


DAVID

The Dark Ages VIrtual Department

http://wiki.arcetri.astro.it/bin/view/DAVID/WebHome

S. Bianchi

INAF/Arcetri

B. Ciardi

MPA

P. Dayal

SISSA

C. Evoli

SISSA

A. Ferrara

SNS Pisa

S. Gallerani

INAF/Roma

F. Iocco

IAP

F. Kitaura

SNS Pisa

  • Maselli

  • INAF/Arcetri

R. Salvaterra

INAF/Milano

S. Salvadori

KAI Groningen

R. Schneider

INAF/Arcetri

R. Valiante

Univ. Firenze

M. Valdes

IPMU


Fan et al. (2005)

QSOs constraints on cosmic reionization

SDSS +CFHQS

~40 QSOs

Becker et al. (2003)

@ 5.7<z<6.4

in contrast with

WMAP

Komatsu et al. (2009 / 2010)


Log-Normal model

QSOs, PopII, PopIII

Free parameters:

Modeling reionization

Choudhury

&

Ferrara

(2005/2006)


ERM

LRM

Reionizationmodels

EARLY REIONIZATION (ERM)

LATE REIONIZATION (LRM)

Highly ionizedIGM at z=6

Two-phaseIGM at z >6

Volume

Filling

Factor

Photo-

Ionization

Rate

Data from McDonald & Miralda-Escude’(2001); Bolton etal. (2005/2007); Fan etal.(2006)


ERM

LRM

Statistics of the transmitted flux

Fan et al. (2006)

Songaila (2004)

Data from Fan etal. (2002); Songaila (2004); Fan etal.(2006)


ERM

LRM

GAPS

Gaps in the Lyα forest

Largest gap width distribution

SG, Choudhury, Ferrara (2006)


ERM

LRM

Largest gap width distribution

Comparison with 20 QSOs at 5.7 < z < 6.4 (Fan et al. 2006)

SG, Ferrara, Fan, Choudhury 2008


ERM

LRM

Largest gap width distribution

Comparison with 20 QSOs at 5.7 < z < 6.4 (Fan et al. 2006)

LR

@

SG, Ferrara, Fan, Choudhury (2008)


Transverse proximity effect

background QSO

foreground QSO

Proximity effect

along the line of sight

Gunn-Peterson

through

Transverse

proximity effect


First-ever detection of the Transverse Proximity Effect in the HI Lyα forest

RD J1148+5252

Mpc

QSO1

Mahabal et al. (2005)

Fan et al. (2006)

QSO2

TPE

Peak Spectral Density

See also Worseck et al. 2007

SG, Ferrara, Fan, Choudhury (2008)


Observed absorption spectrum of GRB050904 @ z=6.3

Kawai et al. (2006)

52 Å


Observed absorption spectrum of GRB050904 @ z=6.3

Kawai et al. (2006)

142 Å


Observed absorption spectrum of GRB050904 @ z=6.3

Kawai et al. (2006)

190 Å

DLA

Totani et al. (2006)


Largest gap probability isocontours: GRBs

5%

40%

5%

10%

SG, Salvaterra, Ferrara, Choudhury (2008)

10%

40%

The ERM is 10 times more probable wrt the LRM

The gap sizes are consistent with xHI~10-4.

In agreement with Totani et al. (2006)


Current observational data of QSO absorption spectra

do not require any sudden change in the IGM ionization state @ z~6,

instead favour a highly ionized IGM at these epochs.

First-ever detection of the transverse proximity effect in the HI

Lyα forest along the line of sight towards the highest–z QSO known.

Conclusions: An Early Reionization Model

Further applications of the Early Reionization Model:

Quasar HII regions  see Maselli’s talk (in the afternoon)

Lyα emitters luminosity function see Dayal’s talk (tomorrow)

The analysis of the GRB050904 at z=6.3 confirms the results found in

QSO studies. In particular, the gap size along the observed line of sight

is consistent with xHI ~10-4.

The overall result points towards an extended reionization process

which starts at z>=11 and completes at z>=7,

in agreement with WMAP data.


Transverse proximity effect: observations vs simulations

Peak Spectral Density


PEAKS

Transverse proximity effect in the LOS towards the highest –z QSO.

Observed peaks are much larger than simulated ones

Lower limit on the foreground QSO lifetime

Conclusions


Log-Normal model: observational confirmation


Log-Normal model: observational confirmation

(Becker et al. 2006)

Miralda-Escude’ et al (2000)


Log-Normal model vs MHR00 at z=6

Miralda-Escude’ et al (2000)


Log-Normal model vs MHR00

Miralda-Escude’ et al (2000)


Gap width distribution

SG, Choudhury, Ferrara (2006)


LARGEST Gap width distribution

SG, Choudhury, Ferrara (2006)


Gap width distribution:

LogNormal vs HYDROPM simulations

SG, Choudhury, Ferrara (2006)


redshift

redshift

Modelling a late reionization scenario

LRM

random distribution

of neutral regions

LRMc

clustering

of neutral pixels


Largest dark gap distribution

Gallerani S., Choudhury T., Ferrara A. (2006)


Ionizing

sources

Left over by

reionization

Should the distribution of neutral regions depend

on the clustering of ionizing sources?

2D Maps of neutral hydrogen distribution (Ciardi, Ferrara & White 2003)

Clustering of ionizing sources might not be correlated significantly

with neutral regions in the case of a very high filling factor.


MASS OF DM HALOS

HOSTING

THE IONIZING SOURCES

PEAK

FREQUENCY & SIZE

Transmissivity windows from HII regions


Mo & White (2002)

Hints on the mass of DM halos hosting high-z QSOs

Frequency

Size

Discrepancy

It is unlikely that QSOs HII regions produce peaks consistent with data,

unless

they reside in highly overdense regions.


Observations

High Redshift (HR)

Low Redshift (LR)

Fan et al. (2006)


Simulated spectra

Observed spectra

GAP

GAP

Dark gaps statistics

Dark gaps: “contiguous regions of the spectrum with  > 2.5 over rest frame wavelength intervals greater then 1Å”.

Data from Songaila & Cowie (2002)


QSO1

QSO2

Mpc

Transverse proximity effect: observations

RD J1148+5252

Mahabal et al. (2005)

Fan et al. (2006)


QSO1

QSO2

Mpc

Transverse proximity effect: observations

RD J1148+5252

Mahabal et al. (2005)

Fan et al. (2006)

White et al. (2003)

Wyithe et al. (2005)

Yu (2005)

Shapiro et al. (2006)


Peaks origin:

Underdense

Regions

(case A)

Peak Spectral Density

Transverse proximity effect: simulations

HII

Regions

(case B)

SG, Ferrara, Fan, Choudhury (2007)


Transverse proximity effect: observations vs simulations


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