Integral field near-infrared spectroscopy of II Zw 40

Vanzi, L.; Cresci, G.; Telles, E.; Melnick, J.

doi:10.1051/0004-6361:20078885

Cited by 55 publications

(83 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They are generally not clearly associated to any feature observed in the continuum or in other lines, except for the cloud corresponding to the radio knots 1 and 2, where Brγ and continuum emission is also detected at corresponding location. In particular, the K band nucleus does not show a clear counterpart in H 2 , and the H 2 filaments extends beyond the bright Brγ regions, similar to what was observed by Vanzi et al (2008) in II Zw 40. However, if we compare our H 2 observations with the study of the molecular gas in this galaxy as traced by the CO(J = 2−1) transition observed by Santangelo et al (2009) in the millimeter at the Submillimeter Array (SMA) telescope, we find a strong spatial correlation between the CO and H 2 clouds.…”

Section: Molecular Hydrogensupporting

confidence: 72%

“…This technique provides an unprecedented detailed view of the interstellar medium and star formation in these galaxies, allowing us to obtain spatially resolved information from the emission and absorption line tracers in the NIR. The results derived from the study of the nearby starburst galaxy II Zw 40 were presented in Vanzi et al (2008), while in this paper we discuss the observations obtained on He 2-10 and NGC 5253, two very well known examples of nearby starbursts. Both galaxies are dwarf-irregular, with estimated distances of 9 Mpc for He 2-10 (Vacca & Conti 1992) and 3.3 Mpc for NGC 5253 (Gibson et al 2000): due to their relatively close distances and remarkable properties they have been studied in detail in the past.…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Integral-field near-infrared spectroscopy of two blue dwarf galaxies: NGC 5253 and He 2-10

Cresci

Vanzi

Sauvage

et al. 2010

A&A

Self Cite

View full text Add to dashboard Cite

We present integral field spectroscopy in the near infrared (NIR) of He 2-10 and NGC 5253, two well known nearby dwarf irregular galaxies showing high star-formation rates. Our data provide an unprecedented detailed view of the interstellar medium and star formation in these galaxies, allowing us to obtain spatially resolved information from the NIR emission and absorption line tracers. We study the spatial distribution and kinematics of different components of the interstellar medium (ISM) mostly through the Bracket series lines, the molecular hydrogen spectrum, [FeII] emission, and CO absorptions. Although the ISM is mostly photo-excited, as derived by the [FeII]/Brγ and H 2 line ratios, some regions corresponding to non-thermal radio sources show a [FeII]/Brγ excess due to a significant contribution of SN driven shocks. In He 2-10 we find that the molecular gas clouds, as traced by CO(2−1) and H 2 infrared line, show consistent morphologies and velocities when studied with the two different tracers. Moreover, there is a clear association with the youngest super star clusters as traced by the ionized gas. In the same galaxy we observe a cavity depleted of gas, which is surrounded by some of the most active regions of star formation, that we interpret as a signature of feedback-induced star formation from older episodes of star formation. Finally, we measured high turbulence in the ISM of both galaxies, σ ∼ 30−80 km s −1 , driven by the high star-formation activity.

show abstract

Section: Molecular Hydrogensupporting

confidence: 72%

Section: Introductionmentioning

confidence: 97%

Integral-field near-infrared spectroscopy of two blue dwarf galaxies: NGC 5253 and He 2-10

Cresci

Vanzi

Sauvage

et al. 2010

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…Therefore, we conclude that H 2 vibrational states in the spectrum of PHL 293B are mainly collisionally excited. This is at variance with conclusions made by Vanzi et al (2000) for SBS 0335-052E, Vanzi et al (2008) for II Zw 40, for Mrk 59, and Izotov & Thuan (2011) for II Zw 40, Mrk 71, Mrk 930, Mrk 996 and SBS 0335-052E. There it has been found that fluorescence is the dominating excitation mechanism of H 2 lines in BCDs.…”

Section: H 2 Emissioncontrasting

confidence: 51%

VLT/X-shooter observations of the low-metallicity blue compact dwarf galaxy PHL 293B including a luminous blue variable star

Izotov¹,

Гусева²,

Fricke³

et al. 2011

A&A

View full text Add to dashboard Cite

Context. We present VLT/X-shooter spectroscopic observations in the wavelength range λλ3000-23 000 Å of the extremely metaldeficient blue compact dwarf (BCD) galaxy PHL 293B containing a luminous blue variable (LBV) star and compare them with previous data. Aims. This BCD is one of the two lowest-metallicity galaxies where LBV stars were detected, allowing us to study the LBV phenomenon in the extremely low metallicity regime. Methods. We determine abundances of nitrogen, oxygen, neon, sulfur, argon, and iron by analyzing the fluxes of narrow components of the emission lines using empirical methods and study the properties of the LBV from the fluxes and widths of broad emission lines. Results. We derive an interstellar oxygen abundance of 12+log O/H = 7.71 ± 0.02, which is in agreement with previous determinations. The observed fluxes of narrow Balmer, Paschen and Brackett hydrogen lines correspond to the theoretical recombination values after correction for extinction with a single value C(Hβ) = 0.225. This implies that the star-forming region observed in the optical range is the only source of ionisation and there is no additional source of ionisation that is seen in the NIR range but is hidden in the optical range. We detect three v = 1-0 vibrational lines of molecular hydrogen. Their flux ratios and non-detection of v = 2-1 and 3-1 emission lines suggest that collisional excitation is the main source producing H 2 lines. For the LBV star in PHL 293B we find broad emission with P Cygni profiles in several Balmer hydrogen emission lines and for the first time in several Paschen hydrogen lines and in several He i emission lines, implying temporal evolution of the LBV on a time scale of 8 years. The Hα luminosity of the LBV star is by one order of magnitude higher than the one obtained for the LBV star in NGC 2363≡Mrk 71 which has a slightly higher metallicity 12+logO/H = 7.87. The terminal velocity of the stellar wind in the low-metallicity LBV of PHL293B is high, ∼800 km s −1 , and is comparable to that seen in spectra of some extragalactic LBVs during outbursts. We find that the averaged terminal velocities derived from the Paschen and He i emission lines are by some ∼40-60 km s −1 lower than those derived from the Balmer emission lines. This probably indicates the presence of the wind accelerating outward.

show abstract

“…However, since the first identification of neutron-capture elements lines twenty years ago by Péquignot & Baluteau (1994) in the optical spectrum of the PN NGC 7027, the reported detections of these lines in the optical spectra of Galactic PNe and H ii regions have grown significantly (e. g. Baldwin et al 2000;García-Rojas et al 2009Otsuka et al 2010Otsuka et al , 2011Otsuka & Tajitsu 2013;Peimbert et al 2004;Sharpee et al 2007;Sterling et al 2009;Zhang et al 2005). Other studies have reported the detection of neutron-capture element lines in the near-infrared spectra of Galactic PNe and H ii regions (e. g. Dinerstein 2001;Sterling & Dinerstein 2008;Blum & McGregor 2008) and in other galaxies (e. g. Vanzi et al 2008).…”

Section: Identification Of Neutron-capture Linesmentioning

confidence: 94%

s-process enrichment in the planetary nebula NGC 3918. Results from deep echelle spectrophotometry

García‐Rojas¹,

Madonna²,

Luridiana³

et al. 2015

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

The chemical content of the planetary nebula NGC 3918 is investigated through deep, highresolution (R∼40000) UVES at VLT spectrophotometric data. We identify and measure more than 750 emission lines, making ours one of the deepest spectra ever taken for a planetary nebula. Among these lines we detect very faint lines of several neutron-capture elements (Se, Kr, Rb, and Xe), which enable us to compute their chemical abundances with unprecedented accuracy, thus constraining the efficiency of the s-process and convective dredge-up in NGC 3918s progenitor star. We find that Kr is strongly enriched in NGC 3918 and that Se is less enriched than Kr, in agreement with the results of previous papers and with predicted s-process nucleosynthesis. We also find that Xe is not as enriched by the s-process in NGC 3918 as is Kr and, therefore, that neutron exposure is typical of modestly subsolar metallicity AGB stars. A clear correlation is found when representing [Kr/O] vs. log(C/O) for NGC 3918 and other objects with detection of multiple ions of Kr in optical data, confirming that carbon is brought to the surface of AGB stars along with s-processed material during third dredge-up episodes, as predicted by nucleosynthesis models. We also detect numerous refractory element lines (Ca, K, Cr, Mn, Fe, Co, Ni, and Cu) and a large number of metal recombination lines of C, N, O, and Ne. We compute physical conditions from a large number of diagnostics, which are highly consistent among themselves assuming a three-zone ionization scheme. Thanks to the high ionization of NGC 3918 we detect a large number of recombination lines of multiple ionization stages of C, N, O and Ne. The abundances obtained for these elements by using recently-determined state-of-the-art ICF schemes or simply adding ionic abundances are in very good agreement, demonstrating the quality of the recent ICF scheme for high ionization planetary nebulae.

show abstract

Integral field near-infrared spectroscopy of II Zw 40

Cited by 55 publications

References 59 publications

Integral-field near-infrared spectroscopy of two blue dwarf galaxies: NGC 5253 and He 2-10

Integral-field near-infrared spectroscopy of two blue dwarf galaxies: NGC 5253 and He 2-10

VLT/X-shooter observations of the low-metallicity blue compact dwarf galaxy PHL 293B including a luminous blue variable star

s-process enrichment in the planetary nebula NGC 3918. Results from deep echelle spectrophotometry

Contact Info

Product

Resources

About