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The Cosmic Evolution of Neutral Atomic Hydrogen Gas
University of Sydney
Colloquium
27 November 2014
Philip Lah
Collaborators:
Frank Briggs (ANU)
Jayaram Chengalur (NCRA)
Matthew Colless (ANU)
Roberto De Propris (FINCA)
Michael Pracy (USyd)
Jonghwan Rhee (UWA)
Neutral Atomic Hydrogen Gas
in Galaxies
Galaxy M33: optical
Galaxy M33: HI 21-cm emission
Galaxy M33: optical and HI
Galaxy M33: optical
Why Study Neutral Atomic Hydrogen Gas?
HI Gas and Star Formation
neutral atomic hydrogen gas
cloud (HI)
molecular gas cloud (H
2)
star formation
The Cosmic Evolution
of Star Formation
The History of
Star Formation in the Universe
Why Study Neutral Atomic Hydrogen Gas?
Because you can measure it!
Why Study Neutral Atomic Hydrogen Gas?
Because you can measure it!
The Cosmic Evolutionof
HI Gas
Reionisation
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
1
2
1
236
kms
V
Mpc
d
mJy
S
zM
M LHI
MHI* = 6.2 ×109 M (Zwaan et al. 2003)
HI 21-cm Emission:
The Observations
HI density – HIPASS Zwaan05
HI density – HIPASS Zwaan05
Zwaan 2005 HIPASS 4315 galaxies
blind HI 21 cm emission direct
detection
HI density – ALFALFA Martin10
HI density – ALFALFA Martin10
Martin 2010ALFALFA 10,119 galaxies
blind HI 21 cm emission direct
detection
How to measure?
2. Damped Lyman-α Absorption
Systems
How to measure?
2. Damped Lyman-α Absorption
Systems
Lyman-α Absorption Systems
quasar
hydrogen gas clouds
Lyman-α emission
Lyman-α absorption by clouds
Wavelength
observer
Inte
nsi
ty
Damped Lyman-α
Lyman-α 1216 Å rest frame
Inte
nsi
ty
Wavelength (Å)4200 4400 4600 4800 5000 5200
Lyα emission
QSO 1425+6039 redshift z = 3.2 Keck HIRES optical spectrum
DLALyman-α forest
Damped Lyman-α: The Observations
HI density – Noterdaeme09
HI density – Noterdaeme09
Noterdaeme 2009 SDSS
937 absorbers
Damped Lyman-α
HI density – Noterdaeme12
HI density – Noterdaeme12
Noterdaeme 2012 BOSS
6839 absorbers
Damped Lyman-α
HI density – Zafar13
HI density – Zafar13
Zafar 2013 UVES
122 quasars
Damped Lyman-α
Lower Redshift Damped Lyman-α
HI density – Rao06
HI density – Rao06
Rao 2006 MgII–FeII
systems UV HST
197 systems
Damped Lyman-α
Coadding HI 21 cm Emission Signals
Coadding HI signals
RA
DEC
Radio Data Cube
Frequen
cy
HI red
shift
Coadding HI signals
RA
DEC
Radio Data Cube
Frequen
cy
HI red
shift
positions of optical galaxies
Coadding HI signals
frequency
flux
Coadding HI signals
frequency
flux
z2
z1
z3
z1, z2 & z3 optical redshifts
of galaxies
Coadding HI signals
velocity
z1
z2
z3
flux
velocity
Coadded HI signal
Coadding HI signals
velocity
z1
z2
z3
flux
velocity
Coadded HI signal
Noise m√ NN = number of galaxies
Coadding HI 21 cm Emission:
The Observations
HI density – Lah07
HI density – Lah07
Lah 2007GMRT/Subaru/AAT
154 galaxies
HI 21 cm emission stacking
HI density – Freudling11
HI density – Freudling11
Freudling 2011 AUDS Arecibo 18 galaxies
HI 21 cm emission targeted
HI density – Rhee13
HI density – Rhee13
Rhee 2013 WSRT CNOC 59 + 69 galaxies
HI 21 cm emission stacking
HI density – Delhaize13
HI density – Delhaize13
Delhaize 2013 Parkes 2dFGRS 3277 galaxies HIPASS 2dFGRS 15093 galaxies
HI 21 cm emission stacking
HI density – VVDS14
HI density – VVDS14HI 21 cm emission stacking
Rhee thesis VVDS14 GMRT/AAT/MMT 165 galaxies
HI density – zCOSMOS14
HI density – zCOSMOS14HI 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 StatusCurrent 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
Abell 370 cluster core, ESO VLT image
large galaxy cluster of order same size
as Coma similar cluster
velocity dispersion and
X-ray gas temperature
cluster redshifts
AAT
Distribution of galaxies around Abell 370com
plete GM
RT
redshift range
Distribution of galaxies around Abell 370
cluster redshift
8 Mpc radius
region: 220
galaxies
Inner Cluster Region
Outer Cluster Region
HI density
Inner Cluster Region
Outer Cluster Region
HI density
cluster redshift
Distribution of galaxies around Abell 370
cluster redshift
Distribution of galaxies around Abell 370
within R200
region
110 galaxies
Inner Cluster Region
Outer Cluster Region
HI density
The Next Generation of Observations
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
SKA1 SYSTEM BASELINE DESIGN 2013-03-12
Giant Metrewave Radio Telescope
• 45 m diameter dishes
• 30 dishes
• low frequency
HI density – GMRT
1000 MHz
~610 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 sky- 9600 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 sky- 9600 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 sky- 9600 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, 3200 hrs, deeper pointings HI stacking using WiggleZ redshifts
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) – z > 1.0, ~5000 hours, single pointing 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
A Radio Gravitational Arc?
Radio ArcV band optical
image from ANU 40 inch
Abell 370 cluster
8 arcmin square
Radio ArcV band optical
image from ANU 40 inch
Abell 370 cluster
8 arcmin square
Radio Arcoptical 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 Arc50 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.∼
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
Radio Arc50 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.∼
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
Radio Arc Theory
Arc model based on Parametric Mass Model of Abell 370 published by Richard et al. (2010).images are 30.3 arcsec across, contour spacing geometric progression, with a factor 1.5 in between each contour
Giant Metrewave Radio Telescope
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