The Cosmic Evolution of
Neutral Atomic
Hydrogen Gas
Philip Lah
AAO
Colloquium
5th February 2015
Collaborators:
Frank Briggs (ANU)
Jayaram Chengalur (NCRA)
Matthew Colless (ANU)
Roberto De Propris (FINCA)
Michael Pracy (USyd)
Jonghwan Rhee (UWA)
Why Study
Neutral Atomic
Hydrogen Gas?
Galaxy M33: optical
Galaxy M33: HI 21-cm emission
Galaxy M33: optical and HI
Galaxy M33: optical
HI Gas and Star Formation
neutral atomic
hydrogen gas
cloud (HI)
molecular gas
cloud (H2)
star formation
The
Cosmic Evolution
of
Star Formation
The
History of
Star Formation
in the Universe
The Cosmic Evolution
of
HI Gas
HI density – nothing
How to measure?
1. HI 21-cm
Emission
How to measure?
1. HI 21-cm
Emission
Neutral atomic hydrogen
creates 21 cm radiation
proton
electron
Neutral atomic hydrogen
creates 21 cm radiation
Neutral atomic hydrogen
creates 21 cm radiation
Neutral atomic hydrogen
creates 21 cm radiation
Neutral atomic hydrogen
creates 21 cm radiation
photon
Neutral atomic hydrogen
creates 21 cm radiation
Neutral atomic hydrogen
creates 21 cm radiation
HI 21 cm emission decay half life
~10 million years
HI Mass
Assuming an optically thin neutral hydrogen cloud
 M HI

 M
 236  S  d L 
 



 1  z  mJy  Mpc 
2
 V 

1 
 kms 
MHI* = 6.2 ×109 M (Zwaan et al. 2003)
HI 21-cm
Emission:
The Observations
HI density – HIPASS Zwaan05
HI density – HIPASS Zwaan05
blind HI 21 cm
emission direct
detection
Zwaan 2005
HIPASS 4315 galaxies
HI density – ALFALFA Martin10
HI density – ALFALFA Martin10
blind HI 21 cm
emission direct
detection
Martin 2010
ALFALFA 10,119 galaxies
How to measure?
2. Damped Lyman-α
Absorption
Systems
How to measure?
2. Damped Lyman-α
Absorption
Systems
Lyman-α Absorption Systems
hydrogen gas clouds
Intensity
observer
quasar
Lyman-α absorption by clouds
Lyman-α emission
Wavelength
Damped Lyman-α
Intensity
QSO 1425+6039 redshift z = 3.2
Keck HIRES optical spectrum
Lyα emission
Lyman-α forest
4200
4400
DLA
4600
4800
5000
5200
Wavelength (Å)
Lyman-α 1216 Å rest frame
Damped Lyman-α:
The Observations
HI density – Noterdaeme09
HI density – Noterdaeme09
Damped Lyman-α
Noterdaeme
2009 SDSS
937 absorbers
HI density – Noterdaeme12
HI density – Noterdaeme12
Damped Lyman-α
Noterdaeme
2012 BOSS
6839 absorbers
HI density – Zafar13
HI density – Zafar13
Damped Lyman-α
Zafar 2013
UVES
122 quasars
Lower Redshift
Damped Lyman-α
HI density – Rao06
HI density – Rao06
Damped Lyman-α
Rao 2006
MgII–FeII
systems
UV HST
197 systems
Coadding HI 21 cm
Emission Signals
Coadding HI signals
Radio Data
Cube
DEC
RA
Coadding HI signals
Radio Data
Cube
DEC
positions of
optical galaxies
RA
flux
Coadding HI signals
frequency
Coadding HI signals
z1
flux
z2
z3
frequency
z1, z2 & z3
optical redshifts
of galaxies
Coadding HI signals
z1
flux
z2
Coadded
HI signal
z3
velocity
velocity
Coadding HI signals
z1
flux
z2
Coadded
HI signal
z3
velocity
velocity
Noise m√ N
N = number of galaxies
Coadding HI 21 cm
Emission:
The Observations
HI density – Lah07
HI density – Lah07
HI 21 cm emission stacking
Lah 2007
GMRT/Subaru/AAT
154 galaxies
HI density – Freudling11
HI density – Freudling11
HI 21 cm emission targeted
Freudling 2011
AUDS Arecibo 18 galaxies
HI density – Rhee13
HI density – Rhee13
HI 21 cm emission stacking
Rhee 2013
WSRT CNOC 59 + 69 galaxies
HI density – Delhaize13
HI density – Delhaize13
HI 21 cm emission stacking
Delhaize 2013
Parkes 2dFGRS 3277 galaxies
HIPASS 2dFGRS 15093 galaxies
HI density – VVDS14
HI density – VVDS14
HI 21 cm emission stacking
Rhee thesis VVDS14
GMRT/AAT/MMT 165 galaxies
HI density – zCOSMOS14
HI density – zCOSMOS14
HI 21 cm emission stacking
Rhee thesis
GMRT/zCOSMOS
HI density – Hoppmann14
HI density – Hoppmann14
HI 21 cm emission targeted
Hoppmann 2014
AUDS Arecibo 105 galaxies
HI density – Current Status
Current Status
HI density – Low z average
4σ
HI density – High z average
7σ
Neutral Atomic
Hydrogen Gas
In
Different Environments
Nearby Galaxy Clusters
Are Deficient
In
HI Gas
HI Deficiency in Clusters
DefHI =
log(MHI exp.
/ MHI obs)
DefHI = 1
is 10% of
expected
HI gas
Gavazzi et al. 2006
expected gas
estimate based
on optical
diameter and
Hubble type
Cluster Stacking
Observations
Abell 370, a galaxy cluster at z = 0.37
large galaxy cluster
of order same size
as Coma
 similar cluster
velocity dispersion
and X-ray gas
temperature
Abell 370 cluster core, ESO VLT image
Distribution of galaxies around Abell 370
complete GMRT redshift range
cluster
redshifts
AAT
Distribution of galaxies around Abell 370
8 Mpc
radius
region:
220
galaxies
cluster
redshift
HI density
Outer
Cluster
Region
Inner
Cluster
Region
HI density
Outer
Cluster
Region
Inner
Cluster
Region
Distribution of galaxies around Abell 370
cluster
redshift
Distribution of galaxies around Abell 370
110
galaxies
cluster
redshift
within
R200
region
HI density
Outer
Cluster
Region
Inner
Cluster
Region
Galaxy HI mass
vs
Star Formation Rate
Galaxy HI Mass vs Star Formation Rate
HIPASS
&
IRAS
data
z~0
Doyle &
Drinkwater
2006
Star Formation
In The
Fujita Galaxies
HI Mass vs Star Formation Rate at z = 0.24
all 121
galaxies
line from
Doyle &
Drinkwater
2006
HI Mass vs Star Formation Rate at z = 0.24
42 bright
L(Hα)
galaxies
42 medium
L(Hα)
galaxies
line from
Doyle &
Drinkwater
2006
37 faint
L(Hα)
galaxies
Galaxy Cluster
Abell 370
HI Mass vs Star Formation Rate in Abell 370
all 168
[OII]
emission
galaxies
Average
line from
Doyle &
Drinkwater
2006
HI Mass vs Star Formation Rate in Abell 370
81 blue [OII]
emission
galaxies
Average
87 red [OII]
emission
galaxies
line from
Doyle &
Drinkwater
2006
Radio Continuum
In The
Fujita Galaxies
Star Formation Rate
from
Hα Emission
and
Radio Continuum
Emission
Halpha vs. RC
line from
Sullivan et al.
2001
Radio Continuum
In The
Galaxy Cluster
Abell 370
Star Formation Rate
from
[OII] Emission
and
Radio Continuum
Emission
Radio Continuum vs. [OII] Star Formation Rate
Average
line from
Bell 2003
all 168
[OII]
emission
galaxies
Radio Continuum vs. [OII] Star Formation Rate
Average
87 red [OII]
emission
galaxies
81 blue [OII]
emission
galaxies
line from
Bell 2003
The Next Generation of
Observations
SKA1
SYSTEM
BASELINE
DESIGN
2013-03-12
Radio Telescopes
SKA1
SYSTEM
BASELINE
DESIGN
2013-03-12
Radio Telescopes
SKA1
SYSTEM
BASELINE
DESIGN
2013-03-12
Radio Telescopes
SKA1
SYSTEM
BASELINE
DESIGN
2013-03-12
Radio Telescopes
Giant Metrewave Radio Telescope
• 45 m diameter dishes
• 30 dishes
• low frequency
HI density – GMRT
~610 MHz
1000 MHz
Karl G. Jansky Very Large Array
• 25 m diameter dishes
• 27 dishes
• high frequency
HI density –JVLA
1000 MHz
JVLA HI Survey
• CHILES (the COSMOS HI Large Extragalactic Survey)
– z = 0 to 0.45, 1000 hours in B array
ASKAP
• 12 m diameter dishes
• 36 dishes
• focal plane array
HI density – ASKAP
700 MHz
ASKAP HI Surveys
• WALLABY (Widefield ASKAP L-Band Legacy All-Sky
Blind Survey) - z = 0 to 0.26 - 75% of the entire sky9600 hrs
• DINGO (Deep Investigations of Neutral Gas Origins) z = 0 to 0.4 - GAMA regions - 7500 hrs, ~290 deg2
• FLASH (The First Large Absorption Survey in HI) - a
blind HI absorption-line survey, out to z = 1.0, 3000 deg2,
2400 hrs, HI stacking using WiggleZ redshifts
ASKAP HI Surveys
• WALLABY (Widefield ASKAP L-Band Legacy All-Sky
Blind Survey) - z = 0 to 0.26 - 75% of the entire sky9600 hrs
• DINGO (Deep Investigations of Neutral Gas Origins) z = 0 to 0.4 - GAMA regions - 7500 hrs, ~290 deg2
• FLASH (The First Large Absorption Survey in HI) - a
blind HI absorption-line survey, out to z = 1.0, 3000 deg2,
2400 hrs, HI stacking using WiggleZ redshifts
ASKAP HI Surveys
• WALLABY (Widefield ASKAP L-Band Legacy All-Sky
Blind Survey) - z = 0 to 0.26 - 75% of the entire sky9600 hrs
• DINGO (Deep Investigations of Neutral Gas Origins) z = 0 to 0.4 - GAMA regions - 7500 hrs, ~290 deg2
• FLASH (The First Large Absorption Survey in HI) - a
blind HI absorption-line survey, 0.5 < z <1.0, 25000 deg2,
1600 hrs
MeerKAT
South African SKA pathfinder
• 13.5 m diameter dishes
• 64 dishes
HI density – MeerKAT
580 MHz
MeerKAT HI Surveys
• LADUMA – (Looking At the Distant Universe with the
MeerKAT Array) – going out to z > 1.0, ~5000 hours,
single pointing targeting Extended Chandra Deep Field
South (ECDF-S)
The SKA-mid
The SKA-mid
• 64 × 13.5-m diameter
dishes from the
MeerKAT array and
190 × 15-m dishes
•
~15% of full SKA
HI density – SKA-mid
350 MHz
Then On To The
SKA
Additional
Slides
An Unusual Object In
Galaxy Cluster
Abell 370
Radio Arc
V band optical
image from
ANU 40 inch
Abell 370
cluster
8 arcmin square
Radio Arc
V band optical
image from
ANU 40 inch
Abell 370
cluster
8 arcmin square
Radio Arc
optical image
from Hubble
Space Telescope
optical arc in
Abell 370 was
the first detected
gravitational
lensing event by
a galaxy cluster
(Soucail et al.
1987)
Radio Arc
50 arcsec on a
side
radio contour
levels start at
28.5 μJy/
beam (3σ)
VLA L-band
radio data has
a synthesised
beam size of
∼1.5 arcsec.
Radio Arc
small galaxy
observed with
LRIS on Keck
optical
spectrum
z = 0.374
small
galaxy
within cluster
VLA C-band 4860 MHz
30 arcsec
on a side
Peak 160
µJy/Beam
VLA L-band 1400 MHz
30 arcsec
on a side
Peak 350
µJy/Beam
GMRT 1040 MHz
30 arcsec
on a side
Peak 490
µJy/Beam
Theoretical Model of Arc
- based on Parametric Mass Model of Abell 370 by Richard et al. (2010)
- images are 30.3 arcsec across, contour spacing geometric progression,
with a factor 1.5 in between each contour
HI 21cm emission
• HI 21 cm emission decay half life ~10 million years
• 1 M  1.2  1057 atoms of hydrogen atoms
• total HI gas in galaxies ~ 107 to 1010 M
• HI 21 cm luminosity of ~2  1032 to 2  1035 ergs s-1
• in star forming galaxies  luminosity of H emission
~3  1039 to 3  1042 ergs s-1
HI density –Molonglo??
Molonglo
Bandwidth 3 MHz
Centre frequency 843 MHz
z = 0.681 to 0.687