Ionized and neutral gas in the starburst galaxy NGC 5253 Australia Telescope National Facility (ATNF, Australia) Galaxies in the Local Volume – Sydney – 9 July 2007 Australia Telescope National Facility (ATNF, Australia) Galaxies in the Local Volume – Sydney – 9 July 2007 Ángel R. López Sánchez

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 The galaxy NGC 5253 D Hel = 3.3 Mpc (Gibson et al. 2000) Scale: 16 pc / arcsec Optical size: 5.0’  1.9’ Classified as Im pec, H II starburst (NED), blue compact dwarf galaxy One of the closest starbursts, observed at all wavelengths It belongs to the M83 subgroup of the Centaurus Group Other names: – HARO 10, – UGCA 369, – IRAS , – PGC , – AM , – HIPASS J A 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 M 83 subgroup 5º Koribalski 2006 Koribalski et al. In preparation

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 NGC 5253 new optical and radio observations Optical deep VLT echelle spectroscopy – 8.2m Kueyen, 30 March 2003 – Slit 12”  1.5” size, PA 0º, 3100 – Å – Excellent seeing, ~0.5” – High spatial (0.18 arcsec/pix) and spectral (0.02 Å/pix) resolution – Study performed with César Esteban (IAC), Jorge García-Rojas (IAC), Manuel Peimbert (UNAM) & Mónica Rodríguez (INAOE), López-Sánchez et al. 2007, ApJ 656, GHz data (H I and continuum) from the ATCA – Data from LVHIS project (Koribalski et al.) – Combining data from 1.5km, 750m and EW367m arrays 8.2m VLT ATCA ionized gas neutral gas

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 NGC 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. López-Sánchez, Esteban, García-Rojas, Peimbert & Rodríguez 2007, ApJ 656, 168 and López-Sánchez PhD Thesis A B C D NGC 5253 – 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.

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 NGC 5253: Deep VLT echelle spectroscopy

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 Detection of O and C recombination lines (RLs) in NGC 5253 RLs are very weak! (10 3 to 10 4 weaker than CEL) Abundances using CEL lines depend strongly on Te, but in RL lines the Te dependence is weak PROBLEM: Abundance discrepancy: O ++ /H + (RL) O ++ /H + (CEL) The abundance discrepance is also found in NGC 5253 and with similar values than that obser- ved in Galactic H II regions! (García-Rojas et al. 2004, 2005, 2006; Esteban et al. 2004) Te Fluctuations? (Peimbert 1967; Esteban 2002) > NGC 5253: Deep VLT echelle spectroscopy López-Sánchez et al. 2007, ApJ 656, 168

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 NGC 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. 12+log O/H = 8.28 log N/O = – log O/H = 8.18 log N/O = – 0.91 López-Sánchez et al. 2007, ApJ 656, 168

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 NGC 5253 VLA H I total intensity ( contours ) and optical image ( gray image ), Kobulnicky & Skillman, 1995, ApJ, 454, L121 NGC 5253: H I radio data New radio data of NGC 5253 from the LVHIS project using three different ATCA arrays: 1.5A, 2x750A, EW367, no ant km/s resolution, 32 channels Beam size: 86”  47”, PA 5º rms ~ 1.9 mJy /beam NGC 5253 ATCA H I total intensity ( false color ) and DSS R optical image ( contours ) Kobulnicky & Skillman, 1995

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 Total H I flux: ATCA: 31.1  1.5 Jy km/s VLA: 33.4  9.9 Jy km/s (Paturel et al. 2003) H I mass: (8.0  0.4)  10 7 M  Dynamical mass: ~10 8 M  NGC 5253: H I radio data NGC 5253 – H I map (blue) + R (green) + H  (red)

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 NGC 5253: H I radio data Optical major axis Rotation? NGC 5253 ATCA H I velocity field H I velocity field: Rotating about the optical MAJOR axis?

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 NGC 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? See poster “Interactions and star formation activity in Wolf-Rayet galaxies” and López-Sánchez PhD Thesis. H I velocity field: Rotating about the optical MAJOR axis?

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 NGC 5253: H I radio data H I velocity field: Rotating about the optical MAJOR axis? Any kind of outflow? Formation of a polar ring? Interaction with M83 ~1000 Ga ago? Disruption/accretion of a gas-rich companion? See poster “Interactions and star formation activity in Wolf-Rayet galaxies” and López-Sánchez PhD Thesis.

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July GHz radio-continuum: S 1.4 GHz = 87.1  3.5 mJy S 1.4 GHz = 85.8  3.4 mJy (Yun et al. 2001) Star Formation Rate: SFR 1.4 GHz ~ 0.03 M  yr -1 (using Condon et al. 2002) SFR FIR ~ 0.08 M  yr -1 (using IRAS fluxes and Kennicutt 1998) SFR H  ~ 0.27 M  yr -1 (Calzetti et al. 2004) NGC 5253: H I radio data NGC 5253 – R map GHz continuum

IONIZED AND NEUTRAL GAS IN THE STARBURST GALAXY NGC 5253 Ángel R. López-Sánchez Galaxies in the Local Volume Sydney – 9 July 2007 Conclusions NGC 5253 is still a puzzling BCD galaxy. IONIZED GAS in the center of the starburst using VLT: – Detection of O and C recombination lines, the first time in a starburst – We confirm a localized N enrichment and possible He pollution, consistent with the existence of WR stars. NEUTRAL GAS combining data from LVHIS project: – Distribution and mass of H I. – VERY intringuing H I kinematics... Outflow, interaction M83 / gas-rich companion? NGC 5253 – H I map (blue) + R (green) + H  (red)