The faint end …. …. in neutral gas. “luminous”
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Transcript of The faint end …. …. in neutral gas. “luminous”
the faint end ….
…. in neutral gas
“luminous”
Radio spectroscopy
Upper limits to space density of intergalactic HI Clouds
# Clouds /Mpc3
/decade
MHI
-
-
-
-
-
Volu
me
(Mp
c3)
Volume for each survey that was
sensitive to MHI
MHI
Upper limits to space density of intergalactic HI Clouds
# Clouds /Mpc3
/decade
MHI
HI in Galaxies
Upper limits to space density of intergalactic HI Clouds
# Clouds /Mpc3
/decade
MHI
Lo & Sargent (1979) M81, CVn, NGC 1023 Groups
Log MHI 6.8 6.6 7.9 7.8 7.7 8.1 Mpg -8.7 -12.3 -11.5 -13.1 -15.2 –15.5
MHI /L 18 0.4 15 3 0.4 1.3
… the writing is on the wall…
(… and in the literature…)
more HI in M96 than the Ring
(Schneider etal 1989)
Giovanelli, Haynes, Chengalur
“Virgo HI Cloud”
HI Mass Function: (dashed curve)
Felton 1985, Luminosity FunctionF-T for MHI/L(L)
HI Content according to galaxy mass
Integral HI mass content:
7.0x107 Mo Mpc-3
(HIMF faint end slope: = -1.28 )
Integral HI mass content:
6.1x107 Mo Mpc-3
( faint end slope: = -1.3 )
Parkes HIPASS results (2003):
(1990)
… what else in the meanwhile…
Relation of Galactic High Velocity Clouds to IGM…
… HVCs mostly within 200 kpc (Zwaan 2000, thesis)
HIPark – a parked Parkes survey
Goals: ultra sensitive to low column densities
How sensitive ?… optically thin at the Lyman limit
exercise in observational techniques … rfi, passband calibration, …
good match to long maintenance periods
diffuse clouds in diffuse clouds in LG LG
& Milky Way halo& Milky Way halo
HI Park proposers…
• Briggs• Barnes• de Blok• Freeman
• Gibson• Korbalski• Reynolds• Staveley-Smith• Zwaan
Progess: 25 days observations – John Reynolds
extragalactic preview – Jackie Cooper
CIVMgII/ Lyman limit(CII, FeII, SiII, …)
MOTIVE ? QSO absorption line interception cross sections
Z=3Ly break galaxy
DLADLA
12 14 18 20 22
HI Column density distribution function Petijean etal 1993
Log f(NHI)
-10
-15
-20
Log NHI
Number of interceptions in range: N to N+dN
f(N) dN /unit Z
Lyforest
IGM DLACIV
LL > 1
HI Map of M81 Group
Yun, Ho & Lo 1994
M81
M82
NGC 3077
NGC 3344
HIPARK Goal…
Sensitivity:
to achieve 6 < 3 x 1017 cm-2
need ~ 6 hours of integration per beam
Drift scan: 15’ beam transits in ~ 1 minute
~360 transits
Barnes et al
Multibeam !!!
1x
4x
3x
Feed orientation for drift scans
Path of Survey Strip:
GalacticCoords
Limits ontiny massesin Sculptor…
3x104 dMpc2
solar masses
Dcloud >1 kpc at 250 kpc
… to fill beam
03:34
05:56
R.A.
2200 km/s 0
FORNAX
Dec –32d53’
20:36
22:55
R.A.
2200 km/s 0
Dec –32d53’
Sculptor
(Putman et al)
22:55
01:14
R.A.
2200 km/s 0
SCULPTOR
Dec –32d53’
MagellanicStream
(Putman et al)
DEEPCentaurusSurvey
(Disney et al)
22:55
01:14
R.A.
2200 km/s 0
Dec –32d53’
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
… faint end still not known… ATA… SKA
(no I.G. HI clouds…)
RA
Velo
city
-500
0
1100Sun up !
RA
Velo
city
-500
0
1100
Right Ascension
Velo
city
0
-500
2800One Day – One Beam
RA
Velo
city
-500
0
1100 km/s
Galactic Plane crossing: L ~ 250o
RA
Velo
city
-500
0
1100
RA
Velo
city
-500
0
1100