Do Intergalactic HI Clouds Exist ?Do Intergalactic HI Clouds Exist ?

z = 8 z = 0

A recycled IGM talk

fromthe IAU Symposium

on Recycling the Intergalactic Medium

Do INTERGALACTIC HI CLOUDS exist ?Do INTERGALACTIC HI CLOUDS exist ?

The Short Answer:

z = 8 z = 0 NO !

NEUTRALHydrogen

INTERGALACTIC HI CLOUDSINTERGALACTIC HI CLOUDS

The Short Story: NEUTRALHydrogenHI

• definition …• why should they exist ?• why should they NOT exist?

HI Map of M81 GroupYun, Ho & Lo 1994

M81M82

NGC 3077

HI Map of M81 GroupYun, Ho & Lo 1994

??? INTERGALACTIC ??????Pristine, Primordial gas !!??

NO STARS !!!???

HI Map of M81 GroupYun, Ho & Lo 1994

Pristine, Primordial gas ??

Fuel ongoing Star Formation

Solve metal abundance problems….

Trace “dark” Dark Matter Halos

more HI in M96 than the Ring

(Schneider etal 1989)

HI contours

i.e.

Sea of ionized baryons

StarsStars & HI gasHI gas?? Just HI ??

Cartoon for Z = 0

Radio spectroscopy

Giovanelli- Haynes “Virgo Cloud”Chengalur et al 1995

.

Limits on I.G. HI Clouds:

1980 Fisher & Tully “not cosmologically significant”

Limits on I.G. HI Clouds:

1980 Fisher & Tully “not cosmologically significant”

1990 Briggs NIGClouds 1

NGalaxies 100

<

Limits on I.G. HI Clouds:

1980 Fisher & Tully “not cosmologically significant”

1990 Briggs NIGClouds 1

NGalaxies 100

<

2000 Zwaan (PhD Thesis) HI Mass Function

Arecibo: HI content according to galaxy mass(Zwaan et al 1997)

Limits on I.G.Clouds

Limits on I.G. HI Clouds:

1980 Fisher & Tully “not cosmologically significant”

1990 Briggs NIGClouds < 1 .

NGalaxies 1002000 Zwaan (PhD Thesis) HI Mass Function

2003 Koribalski/Zwaan ET AL… HIPASS

HIPASS … Parkes TelescopeConsortium: ATNF, Melbourne, Cardiff, RSAA +

Limits on I.G. HI Clouds:

1980 Fisher & Tully “not cosmologically significant”

1990 Briggs NIGClouds < 1 .

NGalaxies 1002000 Zwaan (PhD Thesis) HI Mass Function

2003 Koribalski/Zwaan ET AL… HIPASS 1000’s of galaxies… no I.G. Clouds

HIPASS result… Warren, Jerjen, ET AL

…. a few extremely HI rich galaxiesMHI

Loptical Lsolar

Msolar= 10 – 20

??? I.G. HI Clouds with stellar contamination ???

B.Warren: “They’re galaxies !”

… that’s the observational evidence.

Big Bang Nucleosynthesis+WMAP

.…. i

oniz

ed…

…CMB

dampedLyman-abs-lines

21cm Line Studies (HIPASS)

M-0.5Tot 0

1/3300

Recombination competes with Re-ionization

Time scales for Recombination in IGM…t = n /Rrecomb e = n /(n n )e e p recomb

= 1 /( n ) p recomb

= T /( n 2 x 10) sec p1/2 -11

but, n ~ n proportional ~ (1+z)3 p baryon

t proportional T /(1+z)recomb31/2

Temperature vs Redshift

Tcmb

Tkinetic

Onset of sources of ionizing radiation

Temperature vs Redshift

first ionizing sources

H

Temperature vs Redshift

first ionizing sources

H

QSOs /AGN

He

Age of Universe

Recombination Time (mean density)

Tkinetic

109yr

107yr

1010yr

Galaxy Disk Gas Trec ~ 105yr

low density

i.e.

Sea of ionized baryons

StarsStars & HI gasHI gas?? Just HI ??

Z = 0 Hydrogen must be confined !

Barkana & Loeb:

Dark Matter Halo Mass Function

Z = 30 20 10 5 0

Integral Mass Content per logarithmic interval

Mass Functions

Mass FunctionsDM

baryons

Clusters

Mass Functions

Mass Functions

Mass Functions

Missing bound baryons

i.e.If massive, get

Sea of ionized baryons

Z = 0 Fate of baryons in small halos…?

Sea of ionized baryons

Z = 0 Fate of baryons in small halos…

• Early small halo formation… gas expelled by supernovae

• Late small halo formation… IGM too hot to be captured by a low mass halo

Mhalo ~108Mo => Tvir ~ 104.3 K

Conclusions:

Early Low mass halos Star Formation ISM Lost Late Low mass halos never capture gas, (No Star Formation)

Large mass halos Star Formation Galaxies

No Intergalactic Neutral Hydrogen Clouds at Z=0

… need to recover low metalicity IONIZED IGM & Halo clouds…

NGC 1512: Color coded velocity field

NGC 3344: HI Gas distribution

NGC 3344: HI velocity field

CIV MgII/ Lyman limit(CII, FeII, SiII, …)

Relative interception cross sections for QSO Absorption Lines …

DLA DLA (HI)