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
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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.
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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!
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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 Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel 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.
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
NGC 5253: Deep VLT echelle spectroscopyNGC 5253: Deep VLT echelle spectroscopy
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
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
NGC 5253: Deep VLT echelle spectroscopyNGC 5253: Deep VLT echelle spectroscopy
[O III]
H
[N II]
[O III]
H
[N II]
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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)
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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?
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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!
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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)
The Cosmic Odyssey of the Elements – Jun 23, 2008 Ángel R. López-Sánchez
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?)
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