New southern blue compact dwarf galaxies in the 2dF Galaxy redshift survey

Papaderos, P.; Гусева, Н. Г.; Izotov, Y. I.; Noeske, K. G.; Thuan, T. X.; Fricke, K. J.

doi:10.1051/0004-6361:20054458

Cited by 35 publications

(54 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This clearly indicates that all galaxies have experienced a previous star-formation events long time before those they are now hosting, as concluded in many other previous results (i.e. Cairós et al 2001a,b;Bergvall & Östlin 2002;Papaderos et al 2006;Amorín et al 2009). However, as we previously said (López-Sánchez et al 2004a), this seems not to be true in the particular case of members F of HCG 31, which clearly show no evidences of underlying old stellar populations.…”

Section: Global Analysis Of Magnitudes and Colourssupporting

confidence: 84%

Massive star formation in Wolf-Rayet galaxies

López-Sánchez

Esteban

2010

A&A

125

121

View full text Add to dashboard Cite

Aims. We have performed a comprehensive multiwavelength analysis of a sample of 20 starburst galaxies that show a substantial population of very young massive stars, most of them classified as Wolf-Rayet (WR) galaxies. In this paper, the forth of the series, we present the global analysis of the derived photometric and chemical properties. Methods. We compare optical/NIR colours and the physical properties (reddening coefficient, equivalent widths of the emission and underlying absorption lines, ionization degree, electron density, and electron temperature) and chemical properties (oxygen abundances and N/O, S/O, Ne/O, Ar/O, and Fe/O ratios) with previous observations and galaxy evolution models. We compile 41 independent star-forming regions -with oxygen abundances between 12 + log(O/H) = 7.58 and 8.75 -, of which 31 have a direct estimate of the electron temperature of the ionized gas.Results. According to their absolute B-magnitude, many of them are not dwarf galaxies, but they should be during their quiescent phase. We found that both c(Hβ) and W abs increase with increasing metallicity. The differences in the N/O ratio is explained assuming differences in the star formation histories. We detected a high N/O ratio in objects showing strong WR features (HCG 31 AC, UM 420, IRAS 0828+2816, III Zw 107, ESO 566-8 and NGC 5253). The ejecta of the WR stars may be the origin of the N enrichment in these galaxies. We compared the abundances provided by the direct method with those obtained through empirical calibrations, finding that (i) the Pilyugin method is the best suited empirical calibration for these star-forming galaxies; (ii) the relations provided by Pettini & Pagel (2004, MNRAS, 348, 59) give acceptable results for objects with 12 + log(O/H) > 8.0; and (iii) the results provided by empirical calibrations based on photoionization models are systematically 0.2-0.3 dex higher than the values derived from the direct method. The O and N abundances and the N/O ratios are clearly related to the optical/NIR luminosity; the dispersion of the data is a consequence of the differences in the star-formation histories. The L-Z relations tend to be tighter when using NIR luminosities, which facilitates distinguishing tidal dwarf galaxies candidates and pre-existing dwarf objects. Galaxies with redder colours tend to have higher oxygen and nitrogen abundances. Conclusions. Our detailed analysis is fundamental to understand the nature of galaxies that show strong starbursts, as well as to know their star formation history and the relationships with the environment. This study is complementary -but usually more powerful-to the less detailed analysis of large galaxy samples that are very common nowadays.

show abstract

Section: Global Analysis Of Magnitudes and Colourssupporting

confidence: 84%

Massive star formation in Wolf-Rayet galaxies

López-Sánchez

Esteban

2010

A&A

125

121

View full text Add to dashboard Cite

show abstract

“…In these environments mass-loss rates are so low that even the most massive stars will fail to evolve to a WR phase if main-sequence stellar winds are the only means of stripping their H-envelopes. However, contrary to speculation, evidence of WR populations has been found in these extreme environments, namely the blue compact dwarf galaxies I Zw 18 (Brown et al 2002;Izotov et al 1997;Legrand et al 1997) and SBS 0335-052E (Papaderos et al 2006). Besides main-sequence stellar winds, there must be another mechanism via which a star can lose its H-envelope enabling WR populations to reside within these extremely metal-poor galaxies.…”

Section: Low-metallicity Sne Ic-bl Without Associated Grbsmentioning

confidence: 83%

Two type Ic supernovae in low-metallicity, dwarf galaxies: diversity of explosions

Young¹,

Smartt²,

Valenti³

et al. 2010

A&A

139

132

View full text Add to dashboard Cite

Aims. The aim of this paper is to discuss the nature of two type Ic supernovae SN 2007bg and SN 2007bi and their host galaxies. Both supernovae were discovered in wide-field, non-targeted surveys and are found to be associated with sub-luminous blue dwarf galaxies identified in SDSS images. Methods. We present BVRI photometry and optical spectroscopy of SN 2007bg and SN 2007bi and their host galaxies. Their lightcurves and spectra are compared to those of other type Ic SNe and analysis of these data provides estimates of the energetics, total ejected masses and synthesised mass of 56 Ni. Detection of the host galaxy emission lines allows for metallicity measurements. Results. Neither SNe 2007bg nor 2007bi were found in association with an observed GRB, but from estimates of the metallicities of their host-galaxies they are found to inhabit similar low-metallicity environments as GRB associated supernovae. The radio-bright SN 2007bg is hosted by an extremely sub-luminous galaxy of magnitude M B = −12.4 ± 0.6 mag and an estimated oxygen abundance of 12 + log(O/H) = 8.18 ± 0.17 (on the Pettini & Pagel 2004 scale). The early lightcurve evolution of SN 2007bg matches the fastpace decline of SN 1994I giving it one of the fastest post-maximum decline rates of all broad-lined type Ic supernovae known to date and, when combined with its high expansion velocities, a high kinetic energy to ejected mass ratio (E K /M ej ∼ 2.7). We also show that SN 2007bi is possibly the most luminous type Ic known, reaching a peak magnitude of M R ∼ −21.3 mag and displays a remarkably slow decline, following the radioactive decay rate of 56 Co to 56 Fe throughout the course of its observed lifetime. SN 2007bi also displays an extreme longevity in its spectral evolution and is still not fully nebular at approximately one year post-maximum brightness. From a simple model of the bolometric light curve of SN 2007bi we estimate a total ejected 56 Ni mass of M Ni = 3.5−4.5 M , the largest 56 Ni mass measured in the ejecta of a supernova to date. There are two models that could explain the high luminosity and large ejected 56 Ni mass. One is a pair-instability supernova (PISN) which has been predicted to occur for massive stars at low metallicities. We measure the host galaxy metallicity of SN 2007bi to be 12 + log(O/H) = 8.15 ± 0.15 (on the McGaugh 1991 scale) which is somewhat high to be consistent with the PISN model. An alternative is the core-collapse of a C+O star of 20−40 M which is the core of a star of originally 50−100 M .

show abstract

“…It is very metal-poor and it is classified as iE/iI BCD by Papaderos et al (2006). Compact starburst regions are visible in the outskirts, but the RGB image hints at the presence of diffuse blue regions dispersed throughout the galaxy.…”

Section: Um559mentioning

confidence: 99%

Deep multiband surface photometry on a sample of 24 blue compact galaxies

Micheva

Östlin

Zackrisson

et al. 2013

A&A

View full text Add to dashboard Cite

Aims. We present deep surface photometry of a volume-limited sample of 21 UM emission line galaxies in broadband optical U BVRI and near infrared (NIR) HKs filters. The sample comprises 19 blue compact galaxies (BCGs) and two spirals. Methods. We separated the burst and host populations for each galaxy and compared them to stellar evolutionary models with and without nebular emission contribution. We measured and analyzed the A 180 asymmetry in all filters, the concentration index C, the scale length, and the central surface brightness of the host galaxy. Results. A shift in the average A 180 asymmetry is detected from optical to NIR. This shift seems correlated with the morphological class of the BCGs. Using the color-asymmetry relation, we identify five BCGs in the sample as mergers, which is confirmed by their morphological class. Though clearly separated from normal galaxies in the concentration-asymmetry parameter space, we find that it is not possible to distinguish luminous starbursting BCGs from the merely star forming low luminosity BCGs.

show abstract

New southern blue compact dwarf galaxies in the 2dF Galaxy redshift survey

Cited by 35 publications

References 65 publications

Massive star formation in Wolf-Rayet galaxies

Massive star formation in Wolf-Rayet galaxies

Two type Ic supernovae in low-metallicity, dwarf galaxies: diversity of explosions

Deep multiband surface photometry on a sample of 24 blue compact galaxies

Contact Info

Product

Resources

About