the cosmic odyssey of the elements – jun 23, 2008 Ángel r. lópez-sánchez nitrogen excess in...

The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez

Nitrogen excess in starburst galaxies: chemical enrichment via winds of Wolf-

Rayet stars?

Nitrogen excess in starburst galaxies: chemical enrichment via winds of Wolf-

Rayet stars?

Ángel R. López-SánchezÁngel R. López-Sánchez

César Esteban (IAC), Jorge García-Rojas (IA-UNAM), Adal Mesa Delgado (IAC) & Luis César Esteban (IAC), Jorge García-Rojas (IA-UNAM), Adal Mesa Delgado (IAC) & Luis López-Martín (IAC)López-Martín (IAC)

Ángel R. López-SánchezÁngel R. López-Sánchez

César Esteban (IAC), Jorge García-Rojas (IA-UNAM), Adal Mesa Delgado (IAC) & Luis César Esteban (IAC), Jorge García-Rojas (IA-UNAM), Adal Mesa Delgado (IAC) & Luis López-Martín (IAC)López-Martín (IAC)CSIRO /Australia Telescope National Facility (ATNF, Australia)

The Cosmic Odyssey of the Elements – Aegina – Greece – 23 Jun 2008The Cosmic Odyssey of the Elements – Aegina – Greece – 23 Jun 2008

CSIRO /Australia Telescope National Facility (ATNF, Australia)

The Cosmic Odyssey of the Elements – Aegina – Greece – 23 Jun 2008The Cosmic Odyssey of the Elements – Aegina – Greece – 23 Jun 2008


Chemical evolution of galaxiesChemical evolution of galaxies

elements (S, Ne, Ar): const. with O/H– Primary production in massive stars

(Izotov & Thuan 1999; Izotov et al. 2006)

N/O is not so evident!

elements (S, Ne, Ar): const. with O/H– Primary production in massive stars

(Izotov & Thuan 1999; Izotov et al. 2006)

N/O is not so evident!

– Constant for 12+log O/H < 7.6 Primary production

– Dispersion for 7.6 < 12+log O/H < 8.3 Delay in N production & loss via galactic winds

– Increases for 12+log O/H > 8.3 Secondary production

Kobulnicky et al.1997;

Izotov et al. 2006

– Constant for 12+log O/H < 7.6 Primary production

– Dispersion for 7.6 < 12+log O/H < 8.3 Delay in N production & loss via galactic winds

– Increases for 12+log O/H > 8.3 Secondary production

Kobulnicky et al.1997;

Izotov et al. 2006

log (N/O) ~ 0.5


Starburst galaxies with high N/OStarburst galaxies with high N/O

log (N/O) ~ 0.5 for the typical O/H value– Pustilnik et al. 2004

Common feature: Wolf-Rayet galaxies!

– Winds of the WR stars may produce a N enrichment

– However, the N enrichment should be very localized and a short episode

Observational problem: – [N II] 6548,6583

are very close to H.– + broadening effects (kinematics)

log (N/O) ~ 0.5 for the typical O/H value– Pustilnik et al. 2004

Common feature: Wolf-Rayet galaxies!

– Winds of the WR stars may produce a N enrichment

– However, the N enrichment should be very localized and a short episode

Observational problem: – [N II] 6548,6583

are very close to H.– + broadening effects (kinematics)

New data with enough spectral resolution and a systematic study is needed !!

New data with enough spectral resolution and a systematic study is needed !!

Gaussian fit for H and [N II] in HS 0837+4717 using long-slit spectroscopic data from 6m BTA and a

spectral resolution of 2.38 A/pix (Pustilnik et al. 2004).

Gaussian fit for H and [N II] in HS 0837+4717 using long-slit spectroscopic data from 6m BTA and a

spectral resolution of 2.38 A/pix (Pustilnik et al. 2004).

HS 0837+4717: log (N/O) = +0.8 HS 0837+4717: log (N/O) = +0.8

• ISIS @ 4.2m WHT : 0.36 A/pix

• UVES @ 8.2m VLT: 0.024 A/pix

• ISIS @ 4.2m WHT : 0.36 A/pix

• UVES @ 8.2m VLT: 0.024 A/pix


Wolf-Rayet galaxiesWolf-Rayet galaxies

A subset of emission-line and H II galaxies whose integrated spectra show broad emission features attributed to the presence of Wolf-Rayet stars.

A subset of emission-line and H II galaxies whose integrated spectra show broad emission features attributed to the presence of Wolf-Rayet stars.

Emission lines :Emission lines :

Recombination Recombination lines (RL) of H y Helines (RL) of H y He

Collisionally excitedCollisionally excited lines (CEL) lines (CEL) of O, N, S, Ne, Ar, Cl, Fe ... of O, N, S, Ne, Ar, Cl, Fe ...

Emission lines of WR stars

WN

WC

Last catalogue of WR galaxies 140 objects (Schaerer et al. 1999), nowadays ~250 WR galaxies knownLast catalogue of WR galaxies 140 objects (Schaerer et al. 1999), nowadays ~250 WR galaxies known

– The number of WR stars with respect O stars is high, the burst shoud be short.

– IMF extended to HIGH masses

– Short-lived starburst (< 6 Myr)

– The number of WR stars with respect O stars is high, the burst shoud be short.

– IMF extended to HIGH masses

– Short-lived starburst (< 6 Myr)

Blue WR Bump ~ 4650 Å WNL stars

Blue WR Bump ~ 4650 Å WNL stars

Blue WR Bump ~ 5800 Å WC stars

Blue WR Bump ~ 5800 Å WC stars


1. NGC 1741

2. Mkn 1087

3. Haro 15

4. Mkn 1199

5. Mkn 5

6. POX 4

7. UM 420

8. III Zw 107

9. IRAS 08339+6517

10. IRAS 08208+2816

11. SBS 0926+606

12. SBS 0948+532

13. SBS 1054+365

14. SBS 1211+540

15. SBS 1319+579

16. SBS 1415+437

17. Tol 9

18. Tol 1457-262

19. Arp 252

20. NGC 5253

III Zw 107 SBS 0948+532

SBS 1211+540

SBS 0926+606

Massive star formation in WR galaxiesMassive star formation in WR galaxiesÁ.R. López-Sánchez PhD Thesis (2006) supervised by C. Esteban (IAC):Á.R. López-Sánchez PhD Thesis (2006) supervised by C. Esteban (IAC):

The sample:The sample:

Mkn 5

IRAS 08339+6517

SBS 1415+437SBS 1054+365 UM 420

1. NGC 1741

2. Mkn 1087

3. Haro 15

4. Mkn 1199

5. Mkn 5

6. POX 4

7. UM 420

8. III Zw 107

9. IRAS 08339+6517

10. IRAS 08208+2816

11. SBS 0926+606

12. SBS 0948+532

13. SBS 1054+365

14. SBS 1211+540

15. SBS 1319+579

16. SBS 1415+437

17. Tol 9

18. Tol 1457-262

19. Arp 252

20. NGC 5253

Main aim: Study the massive star formation activity in WR galaxies and the role that

interactions with dwarf objects have in the triggering mechanism of starbursts.

Main aim: Study the massive star formation activity in WR galaxies and the role that

interactions with dwarf objects have in the triggering mechanism of starbursts.

See López-Sánchez & Esteban, 2008, paper I (in rev.) and II & III (in prep.)See López-Sánchez & Esteban, 2008, paper I (in rev.) and II & III (in prep.)

We have performed a detailed analysis of a sample of 20 WR galaxies combining deep optical and NIR broad band and H imaging together with optical spectroscopy (long slit and echelle) data.

We have performed a detailed analysis of a sample of 20 WR galaxies combining deep optical and NIR broad band and H imaging together with optical spectroscopy (long slit and echelle) data.


UM 420UM 420

Located at 237 Mpc At 16.5” from UGC 1809,

located at 97 Mpc It has very blue colors

(U-B) = -0.8 and a lot of H emission,

with SFR = 3.7 Mo/yr

Located at 237 Mpc At 16.5” from UGC 1809,

located at 97 Mpc It has very blue colors

(U-B) = -0.8 and a lot of H emission,

with SFR = 3.7 Mo/yr

UM 420

Disturbed morphology and kinematics New optical spectra (4.2m WHT)

Disturbed morphology and kinematics New optical spectra (4.2m WHT)

UGC 1809

López-Sánchez, 2006, PhDLópez-Sánchez & Esteban, 2008

López-Sánchez, 2006, PhDLópez-Sánchez & Esteban, 2008


UM 420UM 420

New optical spectra (4.2m WHT)– We detect both the WR bump

and the He II 4686 emission line– Very good estimation of Te, Ne and C(H)– Excellent estimation of [N II] and Hfluxes– 12 + log (O/H) = 7.95 ± 0.05– log (N/O) = -1.11 ± 0.08

New optical spectra (4.2m WHT)– We detect both the WR bump

and the He II 4686 emission line– Very good estimation of Te, Ne and C(H)– Excellent estimation of [N II] and Hfluxes– 12 + log (O/H) = 7.95 ± 0.05– log (N/O) = -1.11 ± 0.08

0.4 dex higher than expected! 0.4 dex higher than expected!


NGC 1741 (Mkn 1089)NGC 1741 (Mkn 1089)

NGC 1741 is the main member (A+C) in Hickson Compact Group 31

A very luminous WR galaxy

A merger in progress!!

Optical spectrum (ISIS@WHT)

– We detect the WR bump

– Direct estimation of Te, Ne and C(H)

– 12+log (O/H) = 8.22 ± 0.05– log (N/O) = -1.12 ± 0.10

NGC 1741 is the main member (A+C) in Hickson Compact Group 31

A very luminous WR galaxy

A merger in progress!!

Optical spectrum (ISIS@WHT)

– We detect the WR bump

– Direct estimation of Te, Ne and C(H)

– 12+log (O/H) = 8.22 ± 0.05– log (N/O) = -1.12 ± 0.10

López-Sánchez, Esteban & Rodríguez (2004a), ApJS

López-Sánchez, Esteban & Rodríguez (2004a), ApJS

Typical values! Typical values!


The galaxy NGC 5253The galaxy NGC 5253

DHel= 4.0 Mpc (Karachentsev et al. 2004)

Scale: 19 pc / arcsec Optical size: 5.0’ 1.9’ Classified as Im pec, H II

starburst (NED), BCDG One of the closest

starbursts, observed at all wavelengths

It belongs to the M83 subgroup of the Centaurus Group

Deep analysis of its ionized gas using UVES@VLT López-Sánchez et al. 2007

DHel= 4.0 Mpc (Karachentsev et al. 2004)

Scale: 19 pc / arcsec Optical size: 5.0’ 1.9’ Classified as Im pec, H II

starburst (NED), BCDG One of the closest

starbursts, observed at all wavelengths

It belongs to the M83 subgroup of the Centaurus Group

Deep analysis of its ionized gas using UVES@VLT López-Sánchez et al. 2007

NGC 5253 – B (blue) + V (green) + I (red) 2.5m du Pont telescope, Las Campanas Observatory, combined by Á.R. López-Sánchez

8.8’

NGC 5253 – V (blue) + I (green) + H (red) 2.5m du Pont telescope, LCO (V, I) + 1.5m CTIO (H) combined by Á.R. López-Sánchez


NGC 5253: Deep VLT echelle spectroscopyNGC 5253: Deep VLT echelle spectroscopy

Four independent regions analized in detail:

• Physical conditions: Ne, Te, reddening.

• Chemical abundances: O, N, Ne, S, Cl, Ar, Fe, He, C

• Kinematics of the ionized gas

169 emission lines identified in region B

2 main results:

The confirmation of a localized chemical pollution, The detection of O and C recombination lines.

Four independent regions analized in detail:

• Physical conditions: Ne, Te, reddening.

• Chemical abundances: O, N, Ne, S, Cl, Ar, Fe, He, C

• Kinematics of the ionized gas

169 emission lines identified in region B

2 main results:

The confirmation of a localized chemical pollution, The detection of O and C recombination lines.

López-Sánchez, Esteban, García-Rojas, Peimbert & Rodríguez 2007, ApJ 656, 168

and López-Sánchez PhD Thesis

López-Sánchez, Esteban, García-Rojas, Peimbert & Rodríguez 2007, ApJ 656, 168

and López-Sánchez PhD Thesis

A

B

C

D

NGC 5253 – WFPC @ HST

UV (blue) + H (green) + [S II] (red) Combined by Á.R. López-Sánchez

H contours over the 2200 Å continuum image (Kobulnicky et al. 1997) and our VLT

slit position.



Our deep VLT spectra CONFIRM the strong N overabundance in a particular zone and also suggest He enrinchement.

The comparison of our empirical stellar yields with – those obtained by stellar evolution models

(Meynet & Maeder 2002)– empirical yields for ring nebulae associated

to Galactic WR stars (Esteban et al. 1992)

indicates that few WR stars CAN PRODUCE the observed N and He pollution

The amount of enrichment material needed is consistent with the mass lost by the number of WR stars estimated.

Our deep VLT spectra CONFIRM the strong N overabundance in a particular zone and also suggest He enrinchement.

The comparison of our empirical stellar yields with – those obtained by stellar evolution models

(Meynet & Maeder 2002)– empirical yields for ring nebulae associated

to Galactic WR stars (Esteban et al. 1992)

indicates that few WR stars CAN PRODUCE the observed N and He pollution

The amount of enrichment material needed is consistent with the mass lost by the number of WR stars estimated.

12+log O/H = 8.28 log N/O = – 1.50

12+log O/H = 8.18 log N/O = – 0.91

López-Sánchez et al. 2007, ApJ 656, 168



[O III]

H

[N II]

[O III]

H

[N II]


New radio data of NGC 5253 from the LVHIS (Local Volume HI Survey) project using three different ATCA arrays

Properties: H I flux: 31.1 1.5 Jy km/s H I mass: (8.0 0.4) 107 M

Dynamical mass: ~108 M

López-Sánchez, Koribalski & Esteban 2007,

New radio data of NGC 5253 from the LVHIS (Local Volume HI Survey) project using three different ATCA arrays

Properties: H I flux: 31.1 1.5 Jy km/s H I mass: (8.0 0.4) 107 M

Dynamical mass: ~108 M

López-Sánchez, Koribalski & Esteban 2007,

NGC 5253: H I radio dataNGC 5253: H I radio data

NGC 5253 – H I map (blue) + R (green) + H (red)


NGC 5253: H I radio dataNGC 5253: H I radio data ESO 154-G023 ATCA H I velocity field

H I velocity field:

Rotating about the optical MAJOR axis? Any kind of outflow? Formation of a polar ring? Interaction with M83 ~1 Gyr ago?

Disruption/accretion of a gas-rich companion

López-Sánchez, Koribalski & Esteban 2007 and Kobulnicky & Skillman 2008

H I velocity field:

Rotating about the optical MAJOR axis? Any kind of outflow? Formation of a polar ring? Interaction with M83 ~1 Gyr ago?

Disruption/accretion of a gas-rich companion

López-Sánchez, Koribalski & Esteban 2007 and Kobulnicky & Skillman 2008

H I velocity field:

Rotating about the optical MAJOR axis?

H I velocity field:

Rotating about the optical MAJOR axis?


Local starburst galaxy IC 10Local starburst galaxy IC 10

Starburst in the Local Group at ~660 kpc

12+log (O/H) = 8.26 (Garnett 1990)

A lot of WR stars! (26 studied by Crowther et al. 2003)

A good place to look for localized N enrichment!


Local starburst galaxy IC 10Local starburst galaxy IC 10

Optical 3D spectra: PMAS@ 3.5m CAHA– 1”/pix, 0.8 A/pix– Detected WR signatures (WR-24 A,

Crowther et al. 2003)– No detection of weak auroral lines (or

affected by an ugly Hg emission line!)– But the maps do not show any evidence

of localized N enrichment

Optical 3D spectra: PMAS@ 3.5m CAHA– 1”/pix, 0.8 A/pix– Detected WR signatures (WR-24 A,

Crowther et al. 2003)– No detection of weak auroral lines (or

affected by an ugly Hg emission line!)– But the maps do not show any evidence

of localized N enrichment

López-Sánchez, López-Martín, Mesa-Delgado & Esteban, 2008, in prep.

López-Sánchez, López-Martín, Mesa-Delgado & Esteban, 2008, in prep.

WRWR


NGC 1512: – SB(r)ab, – Z ~0.7 Zo– D = 9.5 Mpc– Many SF regions

(H and UV-rich)

NGC 1510:– S0, BCD, WR– 5’ = 13.8 kpc

from NGC 1512

12+log(O/H) ~ 7.95log(N/O) ~ -1.2

Using data provided by Storch-Bergmann+ (1995)

NGC 1512: – SB(r)ab, – Z ~0.7 Zo– D = 9.5 Mpc– Many SF regions

(H and UV-rich)

NGC 1510:– S0, BCD, WR– 5’ = 13.8 kpc

from NGC 1512

12+log(O/H) ~ 7.95log(N/O) ~ -1.2

Using data provided by Storch-Bergmann+ (1995) 0.3 dex higher than expected! 0.3 dex higher than expected!

ATCA H I mosaic (3.1 days integr. time)

Interaction features!! Koribalski, López-Sánchez

& McIntyre (2008, sub.)

ATCA H I mosaic (3.1 days integr. time)

Interaction features!! Koribalski, López-Sánchez

& McIntyre (2008, sub.)

NGC 1512NGC 1512

NGC 1510NGC 1510


Conclusions (I)Conclusions (I)

UM 420UM 420Mkn 1089Mkn 1089

XX

NGC 5253 ANGC 5253 A

NGC 5253 CNGC 5253 C

NGC 1510NGC 1510

Data of more galaxies with enough spectral and

Data of more galaxies with enough spectral and spatial resolution to get more definitive results

spatial resolution to get more definitive results (WORK IN PROGRESS(WORK IN PROGRESS)


Conclusions (II)Conclusions (II)

The multiwavelength analysis of a sample of Wolf-Rayet galaxies (López-Sánchez PhD, 2006; López-Sánchez & Esteban 2008) revealed that the majority of them (17 up to 20) show interaction features. New deep data are confirming this result in other WR galaxies.

The multiwavelength analysis of a sample of Wolf-Rayet galaxies (López-Sánchez PhD, 2006; López-Sánchez & Esteban 2008) revealed that the majority of them (17 up to 20) show interaction features. New deep data are confirming this result in other WR galaxies.

Are interactions between dwarf objects the main triggering mechanism of starbursts, specially in BCDGs?

Is this fact related with the detection of N enrichment only in WR galaxies? (Very localized and short event consequence of the recent pollution of the WR winds?)

Are interactions between dwarf objects the main triggering mechanism of starbursts, specially in BCDGs?

Is this fact related with the detection of N enrichment only in WR galaxies? (Very localized and short event consequence of the recent pollution of the WR winds?)

the cosmic odyssey of the elements – jun 23, 2008 Ángel r. lópez-sánchez nitrogen excess in...

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