The Shapes of the HI Velocity Profiles of the THINGS Galaxies

The Shapes of the HI
Velocity Profiles from
THINGS
Erwin de Blok
(ASTRON/UCT)
Roger Ianjamasimanana
Bradley Frank
Moses Mogotsi
Anahi Caldu-Primo
THINGS and HERACLES
teams

THINGS
•
•
•
•
•
The HI Nearby Galaxy Survey - Walter et al (2008)
VLA B,C,D array of 34 nearby Sa-Irr galaxies
distance 3-15 Mpc
~6” spatial (100-500 pc), 2-5 km/s velocity resolution
overlap with SINGS (Spitzer infrared) and GALEX NGS (UV)

THINGS
•
•
•
•
•
The HI Nearby Galaxy Survey - Walter et al (2008)
VLA B,C,D array of 34 nearby Sa-Irr galaxies
distance 3-15 Mpc
~6” spatial (100-500 pc), 2-5 km/s velocity resolution
overlap with SINGS (Spitzer infrared) and GALEX NGS (UV)
HERACLES
•
•
HERACLES - Leroy et al. (2009)
HEterodyne Receiver Array CO Line Extragalactic
Survey
•
•
HERA multipixel receiver on IRAM 30m telescope
Maps CO J=2→1 of entire HI disk of 18 THINGS galaxies
(+others)
•
13” spatial and 2.6 km/s velocity resolution (~ THINGS)

Outline
• Stacking of THINGS HI profiles
•
•
•
Broad and Narrow HI components
Comparison with CO from HERACLES
Narrow-component HI and SF

NGC 2841
THINGS
NGC 3621
NGC 7331
NGC 4826
(M64)
The HI Nearby
Galaxy Survey
NGC 6946
NGC 3198
NGC 3184
NGC 925
NGC 3351
(M95)
NGC 5194
(M51)
NGC 3521
NGC 2366
NGC 4214
NGC 2976
DDO 53
Our Galaxy
HI stars
NGC 1569
M81dwB
M81dwA
NGC 5236
(M83)
IC 2574
NGC 4449
NGC 3627
(M66)
Holmberg II
NGC 7793
DDO 154
NGC 4736
(M94)
NGC 3077
Holmberg I
NGC 5055
NGC 2903
10 kpc
NGC 628
(M74)
NGC 5457
(M101)
NGC 3031
(M81)
NGC 2403
Data: Walter et al 2008
Milky Way HI map: Oort et al (1958)
Milky Way art: NASA/JPL, R. Hurt (SSC)

NGC 2841
THINGS
NGC 7331
observed by
HERACLES
NGC 6946
NGC 3198
NGC 3184
NGC 925
NGC 3351
(M95)
NGC 5194
(M51)
NGC 3521
NGC 4214
NGC 2976
DDO 53
NGC 2366
M81dwB
M81dwA
IC 2574
NGC 4449
Holmberg II
DDO 154
NGC 4736
(M94)
NGC 3077
Holmberg I
NGC 5055
NGC 2903
NGC 628
(M74)
NGC 2403
10 kpc
Data: Walter et al 2008
Milky Way HI map: Oort et al (1958)
Milky Way art: NASA/JPL, R. Hurt (SSC)

NGC 2841
HERACLES
NGC 7331
NGC 6946
NGC 3198
NGC 3184
NGC 925
NGC 3351
(M95)
NGC 5194
(M51)
NGC 3521
NGC 4214
NGC 2976
DDO 53
NGC 2366
M81dwB
IC 2574
Holmberg II
DDO 154
NGC 4736
(M94)
NGC 3077
Holmberg I
NGC 5055
NGC 2903
10 kpc
NGC 628
(M74)
NGC 2403

Needed for star formation
• “Cold” gas a necessary ingredient for star
formation
• Neutral → cold neutral → molecular → SF
• Investigate cold neutral component: mass,
distribution and velocity dispersion

Phases of the Neutral ISM
• Broad: Warm: T ~ 104 K
• Narrow: Cold: T ~ few 100 K
• but dispersions higher -
turbulence et al
Warm
Cold
de Blok & Walter 2006a
also Young & Lo 1997, Braun 1997, etc
de Blok & Walter 2006

Phases of the Neutral ISM
• Broad: Warm: T ~ 104 K
• Narrow: Cold: T ~ few 100 K
• but dispersions higher -
turbulence et al
Warm
Cold
de Blok & Walter 2006a
also Young & Lo 1997, Braun 1997, etc
de Blok & Walter 2006

Phases of the Neutral ISM
• Broad: Warm: T ~ 104 K
• Narrow: Cold: T ~ few 100 K
• but dispersions higher -
turbulence et al
Warm
Cold
de Blok & Walter 2006a
also Young & Lo 1997, Braun 1997, etc
de Blok & Walter 2006

NGC 2841
THINGS
NGC 3621
NGC 7331
NGC 4826
(M64)
The HI Nearby
Galaxy Survey
NGC 6946
NGC 3198
NGC 3184
NGC 925
NGC 3351
(M95)
NGC 5194
(M51)
NGC 3521
NGC 2366
NGC 4214
NGC 2976
DDO 53
Our Galaxy
HI stars
NGC 1569
M81dwB
M81dwA
NGC 5236
(M83)
IC 2574
NGC 4449
NGC 3627
(M66)
Holmberg II
NGC 7793
DDO 154
NGC 4736
(M94)
NGC 3077
Holmberg I
NGC 5055
NGC 2903
10 kpc
NGC 628
(M74)
NGC 5457
(M101)
NGC 3031
(M81)
NGC 2403
Data: Walter et al 2008
Milky Way HI map: Oort et al (1958)
Milky Way art: NASA/JPL, R. Hurt (SSC)

Stacking the profiles
NGC 2366
Ianjamasimanana et al. 2012
(accepted AJ: arXiv:1207.5041)
Shift
Sum
“Super profile”

F
0
F
0
F
0
F
0
4
Flux [Jy beam 1 ]
37.4 37.4
Flux [Jy beam 1 1 ] ]
1.6 1.6 4.2
Super Profiles
146.6 146.6
31.6
200
31.6
150200100150 50100 0 50 50 0 10050 150 100 200 150
Velocity Velocity [km s 1 ][km s 1 ]
200
100 100 350
80 300 80
NGC 3351
DDO NGC154
3351
250
60 60
200
40
150 40
20 100 20
0
50
0
0
Flux [Jy beam 1 ]
1 ]
129.7
200129.7
150 200 100 150 50 100 050 500 100 50 150 100
Velocity Velocity [km s 1 [km ] s 1 ]
200 150 200
100
350 100
300 80 N=279
80
NGC 3351
DDO 154NGC 3351
250
60
200
60
150
40 40
100 20
50
0
0
20.9 8.9
Flux [Jy beam 1 ]
20
0
8.9
Flux [Jy beam 1 ]
1.4 1.4
200 150
3.5
200 80100150 60 50100 40 0 2050 0 10050 20 150 100 40 200 150 60 200 80
Velocity Velocity [km s 1 ][km s 1 ]
200 200 600
150
100
50
0
Flux [Jy beam 1 ]
150
500
400
100
300
200 50
100
0
0
NGC 3184 NGC 3184 3521
3.1 15.7 3.1
2.9 14.5 2.9
100 100 30050 200 50 0100 0 50 100 50 100 200 100 300
Velocity Velocity [km s 1 ][km s 1 ]
Flux
Flux [Jy
[Jy
beam
beam 1 ]
15.6 7.0 7.0
200 80 150 60 200 100 40 150 20 50 100 050 20 500 100 40 50 150 60 100 200 80 150 200
Velocity Velocity [km s 1 [km ] s 1 ]
200 600 200
500
150
400
100 300
200 50
100
0
0
Flux [Jy beam 1 ]
N=1215
150
100
50
0
NGC 3184 3521 NGC 3184
21.3 53.5 21.3
42.7
14.8 14.8
100 300 100 200 50 10050 0 0100 50 20050 100 300 100
Velocity Velocity [km s 1 [km ]
s 1 ]

Profiles
28
1G 2G 1G 2G 1G 2G
30
31
Figure 25. Super profiles of the THINGS galaxies. For each galaxy, we show the results from the single (left panel) and double (middle
panel) Gaussian fitting. The right panels show a fit with a Lorentzian function. The bottom panels of each set of plots show the residuals
from the fits. The filled circles indicate the data. The solid black lines represent the results from the single, the sum of the double Gaussian,
and the Lorentzian fitting. The dotted and the dashed lines in the middle panel represent the narrow and broad components required in
the double Gaussian fitting. We plot error bars as 3 error bars, though in most cases they are smaller than the symbols plotted.
Figure 25. (continued).
Figure 25. (continued).

11
Figure 2. Solid histogram: ratio of the reduced
2 from the triple
and single
Dispersions
Gaussian fits ( 2 3G / 2 1G
). Dotted histogram: ratio of the
reduced 2 from the double and single Gaussian fits ( 2 2G / 2 1G ).
Hatched histogram: ratio of the reduced 2 from the triple and
double Gaussian fits ( 2 3G / 2 2G ).
2G narrow
1G
2G broad
betw
and
is ⇠
From
inpu
This
cube
clina
disp
due
Fi
profi
can
the
com
whe
show
ratio
imp
extr
over
rout
profi
in th
reso
THI
of th

False Super Profiles
• Many ways to get a non-Gaussian super profile
• Inclination and resolution effects
• Dominant narrow profiles
• Thick, lagging component
• Skewed input profiles
• Inaccurate shuffling
• Bulk motions (galaxy interaction, starburst)
• Tested and under control: Ianjamasimanana et al 2012

False Super Profiles
Inclination: 63
• Many ways to get a non-Gaussian super profile
• Inclination and resolution effects
• Dominant narrow profiles
Resolution Velocity Flux ratio Resolution Velocity
dispersion
dispersion
1G n b A n /A b 1G
( 00 ) (pc) (km s 1 ) (km s 1 ) (km s 1 ) (pc) (km s 1 )
4 62 8.6 8.5 15.5 83.3 78 8.1
8 124 8.6 8.6 15.4 60.6 155 8.1
11 171 8.6 8.6 15.4 56.6 213 8.1
20 310 8.9 8.8 15.6 23.4 388 8.2
30 465 9.3 9.0 16.1 12.4 582 8.3
40 621 9.8 9.3 16.8 7.9 776 8.4
50 776 10.1 9.6 17.5 5.6 970 8.6
60 931 10.6 9.8 18.1 4.2 1164 8.8
Inclination: 80
4 62 9.4 9.0 16.1 9.0 78 8.1
8 124 9.5 9.1 16.4 7.7 155 8.1
11 171 9.7 9.2 16.6 6.6 213 8.1
20 310 10.4 9.6 17.7 4.0 388 8.2
30 465 11.4 10.0 19.0 2.6 582 8.3
40 621 12.5 10.6 20.5 1.8 776 8.5
50 776 13.6 11.2 21.9 1.4 970 8.7
60 931 14.9 11.8 23.3 1.2 1164 9.0
Note. — 1G : Velocity dispersion derived from one-component Gaussian fit. n: Velocity dispersion
of the narrow component. b: Velocity dispersion of the broad component. A n /A b :Ratioofthe
fluxes or masses associated with the narrow and broad components. Here, only the single Gaussian
results of the IC 2574 models are shown (see Section 4.1).
• Thick, lagging component
“NGC 2403” at 63 degrees inclination
“NGC 2403” at 80 degrees inclination
• Skewed input profiles
• Inaccurate shuffling
• Bulk motions (galaxy interaction, starburst)
• Tested and under control: Ianjamasimanana et al 2012
Figure 5. Observed and simulated super profiles of NGC 2403 derived after smoothing the model data cubes to the resolution indicated
on the plots. The left and right panels represent the results from the model data cubes of NGC 2403 with input inclination of 63 and 80 ,
respectively. The dotted and the dashed lines represent the narrow and broad components required in the double Gaussian fitting. The
solid lines represent the results of the double Gaussian fitting.

False Super Profiles
• Many ways to get a non-Gaussian super profile
• Inclination and resolution effects
• Dominant narrow profiles
• Thick, lagging component
• Skewed input profiles
• Inaccurate shuffling
• Bulk motions (galaxy interaction, starburst)
• Tested and under control: Ianjamasimanana et al 2012
Figure 8. Top panel: comparison of super profile parameters derived from the faint and bright parts of galaxie
of super profile parameters from the normalized and the original super profiles. The triangle shaped symb

False Super Profiles
• Define clean sample of galaxies not obviously
affected by these systematic effects (also no star burst,
no interaction)
• Example: compare approaching and receding sides

Symmetrical Profiles
SYSTEMATIC UNCERTAINTIES 71
NGC 925
4214
Text
Text
NGC 3621
NGC Text 3627
Text
Text
NGC 7331
NGC 2403
Ho Text I
Text
NGC 4736
Flux Jy beam 1
Flux Jy beam 1
300
250
200
150
100
50
0
50
100 50 0 50 100
Velocity km s 1
200
150
100
50
0
Text
NGC 4449
Text
Text
NGC 7793 IC 2574
NGC Text 5055
NGC
Text
3184
Text
NGC 5236
50
100 50 0 50 100
Velocity km s 1
SYSTEMATIC UNCERTAINTIES
50
Flux Jy beam 1
250
200
150
100
50
0
50
100 50 0 50 100
Velocity km s 1
200
Text
Figure 4.5: NGC Examples 4826 of super profiles of NGC 2366 using LHAP (top left panel), RHAP (top right
panel) and SP (bottom panel)
Flux Jy beam 1
Flux Jy beam 1
200
150
100
0
50
100 50 0 50 100
Velocity km s 1
300
150
100
50
0
asym
asym
sym
Flux Jy beam 1
200
150
100
50
0
50
100
Figure 17. Location of symmetric and asymmetric profiles for the THINGS galaxies. Blue pixels represent symmetric profiles (SP). Green
and red pixels represent left-handed asymmetric profiles (LHAP) and right-handed asymmetric profiles (RHAP), respectively. Ellipses
represent the optical radius r 25 .Thesmallgreycirclesindicatetheapproachingsides.
|vHer3-vIWM| < 5 km s -1 to identify symmetrical profiles
50
100 50 0 50 100
Velocity km s 1
Figure 4.5: Examples of super profiles of NGC 2366 using L
panel) and SP (bottom panel)

Velocity Dispersions
Narrow
Narrow component:
6.5 ± 1.5 kms 1
Broad component:
Broad
16.8 ± 4.3 kms 1

But is this relevant for star formation?

Global Properties
24
narrow/broad
dispersion ratio
narrow/broad
flux ratio
●: symm profs, clean sample
Figure 22. Top panel: velocity dispersion ratio as a function of metallicity, (FUV-NUV) colors and Hα luminosities. Bottom pa
o☐: symm. profs, other galsratio
of the narrow metallicity
and broad components as a function of metallicity, FUV-NUV (FUV-NUV) colors and Hα luminosities. The triangle
represent interacting galaxies (those that are tidally interacting with a nearby companion or are being affected by their environm
are NGC 3031, NGC 4449, NGC 5194, NGC 5457, NGC 3077). The open circle symbols represent galaxies that are disturbed kine

20
σn inside R25 (km s -1 )
n inside r25 [km s 1 ]
An/Ab inside r25
14
12
10
8
6
4
2
2 3 4 5 6 7 8 9
n outside r 25 [km s 1 ]
1.4
narrow
σn outside R25 (km s -1 )
Refining the profiles
4
σb inside R25 (km s -1 )
b inside r25 [km s 1 ]
35
30
25
20
15
10
5
0
4.0
10 15 20 25 30
b outside r 25 [km s 1 ]
1.2
3.5
3.0
1.0
• Do properties change 2.5 as a function of local
radialenvironment?
profiles of the narrow and broad components can
be explained by the fact that the CNM and WNM have
0.8
2.0
di erent densities and therefore have di erent response
•
to incoming radiation. (discussion still in progress)
0.6
1.5
Create super profiles using masks
7.2. Does the narrow component trace molecular gas?
1.0
0.4
( In progress)
•
0.5
0.2 Example: dispersions and mass ratios inside R 8. CONCLUSION
0.0
25 (high star
0.0
0.5
0.0 0.2 0.4forming) 0.6 0.8 1.0 1.2 and 1.4 outside 0.5R25 0.0 0.5(no 1.0 1.5 or 2.0 2.5 very 3.0 3.5 low 4.0 star formation)
A n /A b outside r 25
Deg. asym. outside r 25 [km s 1 ]
Fig. 19.— Top panel :Comparisonofthederivedvelocitydispersionsinsideandoutsider 25 .Theleftpanelisforthenarrowcomponent,
whereas the right panel is for the broad component. Bottom panel: Comparison of the mass ratio of the narrow to that of the broad
component inside and outside r 25 (left panel). The right panel compares the degree of asymmetry (defined as the o set between the peak
velocity of the narrow component and the peak velocity of the broad component) of the super profiles inside and outside r 25 . The solid
lines are lines of equality.
Deg. asym. inside r25 [km s 1 ]
broad
σb outside R25 (km s -1 )
An/Ab inside R25
n inside r25 [k
An/Ab inside r25
8
6
2
2 3 4 5 6 7 8 9
n outside r 25 [km s 1 ]
1.4
1.2
1.0
0.8
0.6
0.4
0.2
mass ratios
0.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
A n /A b outside r 25
An/Ab outside R25
Fig. 19.— Top panel :Comparisonofthederivedvelocitydisper
whereas the right panel is for the broad component. Bottom pa
component inside and outside r 25 (left panel). The right panel co
velocity of the narrow component and the peak velocity of the b
lines are lines of equality.
Preliminary

Radially
13
Figure 6.
Plot of An/Ab ratio as a function of Column density.
Preliminary

Radial trends
13
b
n
velocity dispersion
radius [R25]

Trend with column density
Figure 6.
Plot of An/Ab ratio as a function of Column density.
A n /A b is the flux ratio of the broad and narrow
components

Star formation rates
SUPER PROFILES AND PROPERTIES OF GALAXIES
The Star Formation Efficiency in Nearby Galaxies 67
Define SFR masks using Leroy et al (2008)
THINGS star formation rate maps (24μm
Spitzer and GALEX FUX)
N
N
N
9
8
7
6
5
4
3
2
1
0
6
5
4
3
2
1
0
10
8
6
LOW SFR
10 -4 < SFR < 10 -3 M⊙ yr -1 kpc -2
MEDIUM SFR
10 -3 < SFR < 10 -2 M⊙ yr -1 kpc -2
HIGH SFR
SFR > 10 -2 M⊙ yr -1 kpc -2
4
2
0
0 10 20 30 40 50 60
n,b [km s 1 ]
Preliminary
Figure 5.5: Histograms of the velocity dispersion of the narrow (solid histogr
all profiles, all galaxies
histograms) components derived in low, medium and high SFR regions. The veloci

NGC 2841
HERACLES
NGC 7331
NGC 6946
NGC 3198
NGC 3184
NGC 925
NGC 3351
(M95)
NGC 5194
(M51)
NGC 3521
NGC 4214
NGC 2976
DDO 53
NGC 2366
M81dwB
IC 2574
Holmberg II
DDO 154
NGC 4736
(M94)
NGC 3077
Holmberg I
NGC 5055
NGC 2903
10 kpc
NGC 628
(M74)
NGC 2403

NGC 2403 Example
Bradley S. Frank 1 , W. J. G. de Blok 1,2 ,
The HERACLES Team
1 The Astrophysics, Cosmology and Gravity Centre (ACGC), The University of Cape Town, South Africa
2 Netherlands Institute for Radio Astronomy, ASTRON, Netherlands
Abstract
The HERACLES survey is one the largest and most sensitive survey of CO in nearby galaxies. We compare the kinematics of the HI and the CO in the THINGS galaxies.
In this poster we focus on two galaxies, NGC 3198 and NGC 7331. Both are late-type spirals with a central-depression in the HI emission, which shows high CO
emission in the centre. We derive velocity fields and rotation curves for both galaxies, and show that combining the CO and HI produces a complete rotation curve
for the case of NGC 7331. We find that, in the absence of bars, the overall dynamics of the CO to be very similar to that of the HI.
HI and CO Intensity Maps for NGC 3198
NGC 3198
SB type galaxy -
CO emission
concentrated in
the centre.
HI and CO Velocity Fields (Hermite) for NGC 3198
THINGS-HI
HERACLES-CO
THINGS-HI
HERACLES-CO
PV-Diagram for NGC 3198
THINGS-HI
HERACLES-CO
Rotation Curves for NGC 3198
NGC 3198 was one of the first galaxies for which the kinematics was derived using a tilted-ring model. Here we use the Hermite-polynomial derived velocity-fields
to compute a rotation curve using the tilted-ring model. The effect of the streaming-motions due to the spiral-arms on the rotation curve of the CO can be seen
at 30” and ~ 85”.
HI and CO Intensity Maps for NGC 7331
THINGS-HI
HERACLES-CO
NGC 7331
Sb early-type spiral
- Post-starburst
galaxy - Centraldepression
in HI
emission filled by
CO.
HI and CO Velocity Fields (Hermite) for NGC 7331
THINGS-HI
HERACLES-CO
PV-Diagram for NGC 7331
THINGS-HI
HERACLES-CO
Rotation Curves for NGC 7331
poster by Bradley Frank
Intensity map shows that CO fills the HI “hole”. PV-diagrams shows solid-body like kinematics in centre; velocity fields illustrate the overlap between HI and CO -
ideal for combining rotation curves. Kinematic parameters converge to model after a few iterations, rotation curve in agreement with von Linden et al. (1996)
References: The HI Nearby Galaxy Survey, Walter et al. 2008 - HERACLES: The HERA CO Line Extragalactic Survey, Leroy et al. 2009 -
THINGS Rotation Curves and Mass Models, de Blok et al. 2008 - The Dynamics of the Inner Part of NGC 7331, von Linden 1996

NGC 2403 Example

NGC2403 VELOCITY FIELDS
THINGS
HERACLES
Contours:
-40 to 340 km/s in
steps of 30 km/s

NGC2403 POSITION VELOCITY
major-axis
minor-axis
- HERACLES
- THINGS
contours start from +3σ
in steps of +3σ

NGC2403 ROTATION CURVES
5kpc

CO Dispersions
poster by Moses Mogotsi

NGC 3184 Example

CO dispersions

HI-CO comparisons
σ HI = (1.5 ± 0.2) σ CO
σ HI - σ CO =(7.2 ± 1.3) km/s
Note σ CO and σ HI,narrow similar

Stacking the CO
Anahi Caldu-Primo and Fabian Walter
HI
CO
HI CO
Stack&HI,&CO&spectra&in&bins&of&radius,&SFR,&total&gas
Velocity&Dispersion
as&func>on&of&radius&

Stacking the CO
Anahi Caldu-Primo and Fabian Walter
Ra>o&of&HI/CO&Velocity&Dispersion&…
...&binned&by&Radius
&&&&Ra>o&of&HI/CO&Velocity&Dispersion&for&all&Galaxies
…&binned&by&SFR
…&binned&by&Total&Gas
Average&Ra>o&is&1.41&±&0.34
consistent&with&nonLstacked&value

Summary
• Stacking can be used to identify broad and narrow
components in THINGS galaxy profiles
• Narrow component: 6.5 ± 1.5 km s-1
• Broad component: 16.8 ± 4.3 km s-1
• Dispersions decline exponentially
• Narrow component associated with star formation
• CO dispersions ~1.5 times smaller than “single component” HI
dispersions, and similar to “narrow component” HI dispersion
• Future work: quantify the “narrow HI”-CO (H 2) connection -
“narrow HI” SF law
• Increase S/N of individual profiles, more sophisticated
stacking, smaller areas, CO super profiles