490 likes | 629 Views
Do Intergalactic HI Clouds Exist ?. A recycled IGM talk from the IAU Symposium on Recycling the Intergalactic Medium. z = 8. z = 0. NEUTRAL Hydrogen. NO !. Do INTERGALACTIC HI CLOUDS exist ?. The Short Answer:. z = 8. z = 0. NEUTRAL Hydrogen. HI.
E N D
Do Intergalactic HI Clouds Exist ? A recycled IGM talk from the IAU Symposium on Recycling the Intergalactic Medium z = 8 z = 0
NEUTRAL Hydrogen NO ! Do INTERGALACTIC HI CLOUDS exist ? The Short Answer: z = 8 z = 0
NEUTRAL Hydrogen HI INTERGALACTIC HI CLOUDS The Short Story: • definition … • why should they exist ? • why should they NOT exist?
M82 M81 NGC 3077 HI Map of M81 Group Yun, Ho & Lo 1994
HI Map of M81 Group Yun, Ho & Lo 1994 ??? INTERGALACTIC ?????? Pristine, Primordial gas !!?? NO STARS !!!???
Fuel ongoing Star Formation Solve metal abundance problems…. Trace “dark” Dark Matter Halos HI Map of M81 Group Yun, Ho & Lo 1994 Pristine, Primordial gas ??
more HI in M96 than the Ring (Schneider etal 1989)
i.e. Cartoon for Z = 0 Sea of ionized baryons F ?? Just HI ?? Stars & HI gas
Giovanelli- Haynes “Virgo Cloud” Chengalur et al 1995 .
Limits on I.G. HI Clouds: • Fisher & Tully “not cosmologically significant”
Limits on I.G. HI Clouds: • Fisher & Tully “not cosmologically significant” • 1990 Briggs NIGClouds 1 • NGalaxies 100 <
Limits on I.G. HI Clouds: • Fisher & Tully “not cosmologically significant” • 1990 Briggs NIGClouds 1 • NGalaxies 100 < 2000 Zwaan (PhD Thesis) HI Mass Function
Limits on I.G.Clouds Arecibo: HI content according to galaxy mass (Zwaan et al 1997)
Limits on I.G. HI Clouds: • Fisher & Tully “not cosmologically significant” • 1990 Briggs NIGClouds < 1 . • NGalaxies 100 • 2000 Zwaan (PhD Thesis) HI Mass Function • 2003 Koribalski/Zwaan ET AL… HIPASS
HIPASS … Parkes Telescope Consortium: ATNF, Melbourne, Cardiff, RSAA +
Limits on I.G. HI Clouds: • Fisher & Tully “not cosmologically significant” • 1990 Briggs NIGClouds < 1 . • NGalaxies 100 • 2000 Zwaan (PhD Thesis) HI Mass Function • 2003 Koribalski/Zwaan ET AL… HIPASS • 1000’s of galaxies… no I.G. Clouds
MHI Msolar = 10 – 20 Loptical Lsolar HIPASS result… Warren, Jerjen, ET AL …. a few extremely HI rich galaxies ??? I.G. HI Clouds with stellar contamination ??? B.Warren: “They’re galaxies !”
CMB Big Bang Nucleosynthesis+WMAP .…. ionized……
damped Lyman-a abs-lines 21cm Line Studies (HIPASS)
W W M Tot -0.5 0 1/3300
Recombination competes with Re-ionization
= n /(n n a ) recomb e e p = 1 /( n a ) p recomb 1/2 -11 = T /( n 2 x 10) sec p 3 but, n~ n proportional ~ (1+z) p baryon 3 1/2 t proportional T /(1+z) recomb Time scales for Recombination in IGM… t = n /R recomb e
Onset of sources of ionizing radiation Temperature vs Redshift Tcmb Tkinetic
Temperature vs Redshift first ionizing sources H
QSOs /AGN He Temperature vs Redshift first ionizing sources H
low density Galaxy Disk Gas Trec ~ 105yr Tkinetic Recombination Time (mean density) 1010yr 109yr Age of Universe 107yr
i.e. Hydrogen must be confined ! Z = 0 Sea of ionized baryons F ?? Just HI ?? Stars & HI gas
Barkana & Loeb: Dark Matter Halo Mass Function Z = 30 20 10 50
Integral Mass Content per logarithmic interval
DM Clusters baryons Mass Functions
Mass Functions Missing bound baryons
i.e. If massive, get Z = 0 Fate of baryons in small halos…? Sea of ionized baryons F
Z = 0 Fate of baryons in small halos… Sea of ionized baryons F • 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
Large mass halosStar Formation Galaxies Early Low mass halos Star Formation ISM Lost Late Low mass halos never capture gas, (No Star Formation) No Intergalactic Neutral Hydrogen Clouds at Z=0 … need to recover low metalicity IONIZED IGM & Halo clouds… Conclusions:
DLA (HI) CIV MgII/ Lyman limit (CII, FeII, SiII, …) Relative interception cross sections for QSO Absorption Lines …