1. The CO SED and molecular gas properties in Early-Type Galaxies (ETGs)CS
HCN
S0 galaxy NGC6014. Credit: NASA/ESA
S0 galaxy NGC5866. Credit: NASA/ESA
HCO+
Estelle Bayet (University of Oxford)
Collaborators : M. Bureau (Oxford), T. Davies (Oxford),
A. Crockers (USA) + SAURON and ATLAS3D teams

2. I. Observations: so far… so good!
 review of detections
 first results

3. I. Observations: so far… so good!
 review of detections
 first results
II. Models: so far… not that good!
 results
 limitations

4. I. Observations: so far… so good!
 review of detections
 first results
II. Models: so far… not that good!
 results
 limitations
III. Conclusions and Perspective

5. I. Observations:
- 22 % (56/259) of the volume limited sample of ATLAS3D ETGs are gas-rich
ETGs (Young et al. 2010) i.e. with clear detection of CO(1-0) and CO(2-1) (CO(2-1) is also from Welsch and Sage 2003)

6. I. Observations:
- 22 % (56/259) of the volume limited sample of ATLAS3D ETGs are gas-rich
ETGs (Young et al. 2010) i.e. with clear detection of CO(1-0) and CO(2-1) (CO(2-1) is also from Welsch and Sage 2003)
- 32 %(18/56) of the galaxies in this sample of gas-rich ETGs have been chosen for an observational follow-up in 13CO(1-0), 13CO(2-1), HCN(1-0) and HCO+(1-0) lines (Krips et al. 2010, Crocker et al. 2011)

7. Extracted from Crocker et al 2011
12CO(1-0)
12CO(2-1)
13CO(1-0)
13CO(2-1)
HCN(1-0)
HCO+(1-0)

8. Extracted from Crocker et al 2011
12CO(1-0)
12CO(2-1)
13CO(1-0)
13CO(2-1)
HCN(1-0)
HCO+(1-0)

9. Extracted from Crocker et al 2011
12CO(1-0)
12CO(2-1)
13CO(1-0)
13CO(2-1)
HCN(1-0)
HCO+(1-0)

10. I. Observations:
- 22 % (56/259) of the volume limited sample of ATLAS3D ETGs are gas-rich
ETGs (Young et al. 2010) i.e. with clear detection of CO(1-0) and CO(2-1) (CO(2-1) is also from Welsch and Sage 2003)
- 32 %(18/56) of the galaxies in this sample of gas-rich ETGs have been chosen for an observational follow-up in 13CO(1-0), 13CO(2-1), HCN(1-0) and HCO+(1-0) lines (Krips et al. 2010, Crocker et al. 2011)
Summary:
CO (4 lines) : 100% (18/18)
HCN (1 line) : 66% (12/18)
HCO+ (1 line) : 55% (10/18)
HCN+HCO + (2 lines) : 38% (7/18)

11. I. Observations:
- 22 % (56/259) of the volume limited sample of ATLAS3D ETGs are gas-rich
ETGs (Young et al. 2010) i.e. with clear detection of CO(1-0) and CO(2-1) (CO(2-1) is also from Welsch and Sage 2003)
- 32 %(18/56) of the galaxies in this sample of gas-rich ETGs have been chosen for an observational follow-up in 13CO(1-0), 13CO(2-1), HCN(1-0) and HCO+(1-0) lines (Krips et al. 2010, Crocker et al. 2011)
Summary:
CO (4 lines) : 100% (18/18) I can model two
HCN (1 line) : 66% (12/18) gas phases in ETGs
HCO+ (1 line) : 55% (10/18) (CO and a denser and
HCN+HCO + (2 lines) : 38% (7/18) warmer gas)

12. I. Observations:
Extracted from Crocker et al 2011
Paglione et al.
(2001)’s spirals
NGC1266
NGC1266
NGC1266
R21
GMCs in M31
Brouillet et al.
(2005)
Gao & Solomon
(2004)’s spirals
R10
NGC1266: AGN-driven powerful outflow
NGC3665, 4459 & 4526: very thick gas less affected by SF processes or more enriched in 13CO
- Correlated - ETGs lower than Exceptions: AGN
- ½ have bigger R SB: less dense gas driving chemistry
than R21  gas thinner in ETGs or lot of 13CO or not enough HCO+ effect of global TK and n(H2)? due to low
- Exceptions ionisation rate?

13. II. Models :

14. II. Models : Theory LVG model (van der Tak et al. 2007)
 averaged gas physical properties
TK , <σv> and
density are uniform
Line of sight
- 0D model
- Spherical geometry
- Equation of statistical equilibrium + level population
- collision rates
- Velocity = FWHM of our observations
- TK and density uniform
Radiation intensity = fo(S;escape probabilities of a photon emitted by the molecular transition)
ONE MOLECULE (X) ONLY !!
3 (4) parameters : n(H2), TK, , N(X)/Vel, (12C/13C)
 TB  Amb (Kkms-1)

15. II. Models : In practise
- Extract the FWHM

16. II. Models : In practise - Extract the FWHM
- Make grids of models for all the molecules and all the velocities:
e.g (n(H2), TK, N(12CO))=( cm-3, K, cm-2)
for velocities ranging from 60 to 430 kms-1

17. II. Models : In practise - Extract the FWHM
- Make grids of models for all the molecules and all the velocities:
e.g (n(H2), TK, N(13CO))=( cm-3, K, cm-2)
for velocities ranging from 60 to 430 kms-1

18. II. Models : In practise - Extract the FWHM
- Make grids of models for all the molecules and all the velocities:
e.g (n(H2), TK, N(HCN)=( cm-3, K, cm-2)
for velocities ranging from 60 to 430 kms-1

19. II. Models : In practise - Extract the FWHM
- Make grids of models for all the molecules and all the velocities:
e.g (n(H2), TK, N(HCO+)=( cm-3, K, cm-2)
for velocities ranging from 60 to 430 kms-1

20. II. Models : In practise - Extract the FWHM
- Make grids of models for all the molecules and all the velocities:
e.g (n(H2), TK, N(HCO+)=( cm-3, K, cm-2)
for velocities ranging from 60 to 430 kms-1
 ½ million models run for the 4 species investigated here

21. II. Models : In practise - Extract the FWHM
- Make grids of models for all the molecules and all the velocities:
e.g (n(H2), TK, N(HCN))=( cm-3, K, cm-2)
for velocities ranging from 60 to 430 kms-1
 ½ million models run for the 4 species investigated here
- produce programme which calculates line ratio from models and compare
them to observed ones (χ2 and likelihood)
TWO-components LVG
CO gas component : 12CO(1-0)/13CO(1-0), 12CO(2-1)/13CO(2-1), 12CO(1-0)/12CO(2-1)
HCN/HCO+ gas component: HCN(1-0)/HCO+(1-0)

22. II. Models : In practise - Extract the FWHM
- Make grids of models for all the molecules and all the velocities:
e.g (n(H2), TK, N(HCN))=( cm-3, K, cm-2)
for velocities ranging from 60 to 430 kms-1
 ½ million models run for the 4 species investigated here
- produce programme which calculates line ratio from models and compare
them to observed ones (χ2 and likelihood)
TWO-components LVG
CO gas component : 12CO(1-0)/13CO(1-0), 12CO(2-1)/13CO(2-1), 12CO(1-0)/12CO(2-1)
HCN/HCO+ gas component: HCN(1-0)/HCO+(1-0)
 best models identified, not unique!!!

23. II. Models : Results Results for NGC3605 (D=22.2 Mpc)
(Spatial resol=2.2kpc)
N(CO)

24. II. Models : Results
Best models as predicted by χ2

25. II. Models : Results
Best models as predicted by χ2

26. II. Models : Results
Best models as predicted by χ2

27. II. Models : Results
Best models as predicted by χ2

28. II. Models : Results Results for NGC3605 (D=22.2 Mpc)
(Spatial resol=2.2kpc)
N(CO)

29. II. Models : Results
Best models as predicted by χ2

30. II. Models : Results χ2
likelihood
First CO SEDs
for ETGs !!

31. II. Models : Results χ2 likelihood First CO SEDs for ETGs !! SB: peak
turnover
around CO(7-6)
(e.g. Bayet et al. 2006)

32. II. Models : Results χ2 likelihood First CO SEDs for ETGs !! SB: peak
turnover
around CO(7-6)
(e.g. Bayet et al. 2006)
Mrk 231: flat
(van der Werf’s talk ?)

33. II. Models : Results χ2 likelihood First CO SEDs for ETGs !! SB: peak
turnover
around CO(7-6)
(e.g. Bayet et al. 2006)
Mrk 231: flat
(van der Werf’s talk)

34. Need high-frequency CO and HCN/HCO+ data:
II. Models : Results χ2
likelihood
First CO SEDs
for ETGs !!
Need high-frequency CO and HCN/HCO+ data:
Herschel, JCMT and IRAM-30m proposals
SB: peak
turnover
around CO(7-6)
(e.g. Bayet et al. 2006)
Mrk 231: flat
(van der Werf’s talk)

35. NGC (λ= 3mm)
First CS(2-1) and CS(3-2)
detections in ETGs !!
 presence of dense SF gas
in ETGs, even denser than
the one traced by HCN !!
4/10 : both CS lines detected
3/10 : no lines detected
3/10 : detected only in CS(2-1)
because of bad weather
conditions at pico veleta
(Davis et al., in prep).
methanol
CS(2-1)
NGC5866 (λ= 2mm)
CS(3-2)
methanol

36. Need high-frequency CO and HCN/HCO+ data:
II. Models : Results χ2
likelihood
First CO SEDs
for ETGs !!
Need high-frequency CO and HCN/HCO+ data:
Herschel, JCMT and IRAM-30m proposals
Bright side: we have high resolution maps !!!  successful ALMA proposal on NGC4710 for HCN/HCO+(3-2)
SB: peak
turnover
around CO(7-6)
(e.g. Bayet et al. 2006)
Mrk 231: flat
(van der Werf’s talk)

37. II. Models (on-going):
Spatially resolved n(H2), TK, N(12CO) maps from CARMA and IRAM-PdBI reachable!!! (Topaz et al in prep)

38. II. Models (on-going): CO PVD: Optical PVD:
Spatially resolved n(H2), TK, N(12CO) maps from CARMA and IRAM-PdBI
CO PVD:
Optical PVD:
Temperature: 12CO(2-1) / 12CO(1-0)
Velocity
[N II]
Velocity
Opacity: 12CO(2-1) / 13CO(2-1) Hα
Position
Position

39. III. Conclusions and perspectives Observations :
- More low resolution data at high frequency for CO and HCN/HCO+ to better constrain the model predictions

40. III. Conclusions and perspectives Observations :
- More low resolution data at high frequency for CO and HCN/HCO+ to better constrain the model predictions
- new CS lines (low resolution) to analyse and derive corresponding gas properties:
1) compare with CS extragalactic nearby source sample from Bayet et al. (2010)
2) compare CO and CS ladders in ETGs  SF laws ?

41. III. Conclusions and perspectives Observations :
- More low resolution data at high frequency for CO and HCN/HCO+ to better constrain the model predictions
- new CS lines (low resolution) to analyse and derive corresponding gas properties:
1) compare with CS extragalactic nearby source sample from Bayet et al. (2010)
2) compare CO and CS ladders in ETGs  SF laws ?
- acquire high resolution high frequency maps in CO, HCN/HCO+ and CS
Three gas phases corresponding to gas reservoir, clumps and dense SF regions, respectively in ETGS !!!

42. III. Conclusions and perspectives Observations :
- More low resolution data at high frequency for CO and HCN/HCO+ to better constrain the model predictions
- new CS lines (low resolution) to analyse and derive corresponding gas properties:
1) compare with CS extragalactic nearby source sample from Bayet et al. (2010)
2) compare CO and CS ladders in ETGs  SF laws ?
- acquire high resolution high frequency maps in CO, HCN/HCO+ and CS
Three gas phases corresponding to gas reservoir, clumps and dense SF regions, respectively in ETGS !!!
Models :
- Develop models more specific to ETGs:
1) taking into account high metallicity and α-elements enhancement (Bayet et al in prep)

43. Variation
with
respect
to the
metallicity
(high)
(Bayet et al. 2011, in prep)
Variation
with
respect
to three scenarios of α–elements
enhancements
(Bayet et al. 2011, in prep)

44. III. Conclusions and perspectives Observations :
- More low resolution data at high frequency for CO and HCN/HCO+ to better constrain the model predictions
- new CS lines (low resolution) to analyse and derive corresponding gas properties:
1) compare with CS extragalactic nearby source sample from Bayet et al. (2010)
2) compare CO and CS ladders in ETGs  SF laws ?
- acquire high resolution high frequency maps in CO, HCN/HCO+ and CS
Three gas phases corresponding to gas reservoir, clumps and dense SF regions, respectively in ETGS !!!
Models :
- Develop models more specific to ETGs:
1) taking into account high metallicity and α-elements enhancement (Bayet et al in prep)
2) what is the impact of the UV-upturn on the chemistry?

45. PDR model (UCL_PDR)
(Bayet et al in prep)

46. III. Conclusions and perspectives Observations :
- More low resolution data at high frequency for CO and HCN/HCO+ to better constrain the model predictions
- new CS lines (low resolution) to analyse and derive corresponding gas properties:
1) compare with CS extragalactic nearby source sample from Bayet et al. (2010)
2) compare CO and CS ladders in ETGs  SF laws ?
- acquire high resolution high frequency maps in CO, HCN/HCO+ and CS
Three gas phases corresponding to gas reservoir, clumps and dense SF regions, respectively in ETGS !!!
Models :
- Develop models more specific to ETGs:
1) taking into account high metallicity and α-elements enhancement (Bayet et al in prep)
2) what is the impact of the UV-upturn on the chemistry?

47. Thank
you !!!

48. II. Models : Results Results for NGC3605 (D=22.2 Mpc)
(Spatial resol=2.2kpc)