Massive star formation in Wolf-Rayet galaxies

López-Sánchez, Ángel R.

doi:10.1051/0004-6361/201014295

Cited by 74 publications

(55 citation statements)

References 279 publications

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“…Various studies have addressed this aspect in BCDs (Chiosi 1979;Chiosi & Caimmi 1979;Maeder 1981Maeder , 1983Maeder , 1992Maeder , 1993Chiosi & Maeder 1986;Heger & Woosley 2002;López-Sánchez & Esteban 2009, 2010Zhao et al 2013). The α elements-to-oxygen abundance ratios in two star forming regions in Mrk 22 do not show any significant trends with observed metallicity, in agreement with results presented in Izotov et al (2006).…”

Section: Star Formation and Abundancesmentioning

confidence: 99%

Tidal interaction, star formation and chemical evolution in blue compact dwarf galaxy Mrk 22

Paswan¹,

Omar²,

Jaiswal³

2017

Monthly Notices of the Royal Astronomical Society

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The optical spectroscopic and radio interferometric HI 21 cm-line observations of the blue compact dwarf galaxy Mrk 22 are presented. The Wolf-Rayet (WR) emission line features corresponding to high ionization lines of HeII λ4686 and CIV λ5808 from young massive stars are detected. The ages of two prominent star forming regions in the galaxy are estimated as ∼10 Myr and ∼ 4 Myr. The galaxy has non-thermal radio deficiency, which also indicates a young star-burst and lack of supernovae events from the current star formation activities, consistent with the detection of WR emission lines features. A significant N/O enrichment is seen in the fainter star forming region. The gas-phase metallicities [12 + log(O/H)] for the bright and faint regions are estimated as 7.98±0.07 and 7.46±0.09 respectively. The galaxy has a large diffuse HI envelop. The HI images reveal disturbed gas kinematics and HI clouds outside the optical extent of the galaxy, indicating recent tidal interaction or merger in the system. The results strongly indicate that Mrk 22 is undergoing a chemical and morphological evolution due to ongoing star formation, most likely triggered by a merger.

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Section: Star Formation and Abundancesmentioning

confidence: 99%

Tidal interaction, star formation and chemical evolution in blue compact dwarf galaxy Mrk 22

Paswan¹,

Omar²,

Jaiswal³

2017

Monthly Notices of the Royal Astronomical Society

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“…The degree of symmetry of a velocity field may also be affected by the presence of dust lanes, spiral arms, bars, warps, outflows/inflows, shocks or nuclear activity, minor mergers or even interactions with difuse objects (see, e.g., Fridman et al 2005;Fathi et al 2005;Wong et al 2004;López-Sánchez 2010). Their kinematics imprints could range from ∼10 km s −1 (see Wong et al 2004, for radial inflows) to a few hundred of km s −1 (for outflows from an AGN, see, e.g., Arribas et al 1996).…”

Section: Kinematic Internal Misalignmentmentioning

confidence: 99%

Ionized gas kinematics of galaxies in the CALIFA survey

García-Lorenzo

Márquez

Barrera-Ballesteros

et al. 2014

A&A

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Context. Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. Aims. The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of the CALIFA survey for including kinematical criteria in their selection of targets for specific studies. From the first 200 galaxies observed by CALIFA survey in its two configurations, we present the two-dimensional kinematic view of the 177 galaxies satisfaying a gas content/detection threshold. Methods. After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous Results. At the velocity resolution of CALIFA, most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. Thirty-five percent of the objects present evidence of a displacement between the photometric and kinematic centers larger than the original spaxel radii. Only 17% of the objects in the sample exhibit kinematic lopsidedness when comparing receding and approaching sides of the velocity fields, but most of them are interacting galaxies exhibiting nuclear activity (AGN or LINER). Early-type (E+S0) galaxies in the sample present clear photometric-kinematic misaligments. There is evidence of asymmetries in the emission line profiles in 117 out of the 177 analyzed galaxies, suggesting the presence of kinematically distinct gaseous components located at different distances from the optical nucleus. The kinematic decoupling between the dominant and secondary component/s suggested by the observed asymmetries in the profiles can be characterized by a limited set of parameters. Conclusions. This work constitutes the first determination of the ionized gas kinematics of the galaxies observed in the CALIFA survey. The derived velocity fields, the reported kinematic distortions/peculiarities and the identification of the presence of several gaseous components in different regions of the objects might be used as additional criteria for selecting galaxies for specific studies.

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“…In the case of dwarf galaxies it has been suggested that interactions are responsible for the class of blue compact dwarfs (BCDs; Paudel et al 2015): dwarf galaxies with a significant, centrally concentrated young stellar population (e.g., Gil de Paz et al 2003). In general many dwarf systems with increased star formation rates (SFR) have been found to be irregular or to show signs of disturbances (Taylor et al 1995;Ekta & Chengalur 2010;López-Sánchez 2010;Holwerda et al 2013;Lelli et al 2014b;Knapen & Cisternas 2015), but in a number of cases no visible companion has been found (Brosch et al 2004;Ekta & Chengalur 2010;López-Sánchez 2010;Lelli et al 2014b). Other possible origins of the increase in star formation and the irregular morphology are cosmological gas inflows (see for example Verbeke et al 2014) or re-accretion of material blown out by previous starbursts, and varying internal instabilities (e.g., Meurer et al 1998;van Zee et al 2001;Lelli et al 2014a;Elmegreen et al 2012;Bekki & Freeman 2002).…”

Section: Introductionmentioning

confidence: 99%

Dark influences

Starkenburg

Helmi

Sales

2016

A&A

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Context. It has been proposed that mergers induce starbursts and lead to important morphological changes in galaxies. Most studies so far have focused on large galaxies, but dwarfs might also experience such events, since the halo mass function is scale-free in the concordance cosmological model. Notably, because of their low mass, most of their interactions will be with dark satellites. Aims. In this paper we follow the evolution of gas-rich disky dwarf galaxies as they experience a minor merger with a dark satellite. We aim to characterize the effects of such an interaction on the dwarf's star formation, morphology, and kinematical properties. Methods. We performed a suite of carefully set-up hydrodynamical simulations of dwarf galaxies that include dark matter, gas, and stars merging with a satellite consisting solely of dark matter. For the host system we vary the gas fraction, disk size and thickness, halo mass, and concentration, while we explore different masses, concentrations, and orbits for the satellite. Results. We find that the interactions cause strong starbursts of both short and long duration in the dwarfs. Their star formation rates increase by factors of a few to 10 or more. They are strongest for systems with extended gas disks and high gas fractions merging with a high-concentration satellite on a planar, radial orbit. In contrast to analogous simulations of Milky Way-mass galaxies, many of the systems experience strong morphological changes and become spheroidal even in the presence of significant amounts of gas. Conclusions. The simulated systems compare remarkably well with the observational properties of a large selection of irregular dwarf galaxies and blue compact dwarfs. This implies that mergers with dark satellites might well be happening but not be fully evident, and may thus play a role in the diversity of the dwarf galaxy population.

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Massive star formation in Wolf-Rayet galaxies

Cited by 74 publications

References 279 publications

Tidal interaction, star formation and chemical evolution in blue compact dwarf galaxy Mrk 22

Tidal interaction, star formation and chemical evolution in blue compact dwarf galaxy Mrk 22

Ionized gas kinematics of galaxies in the CALIFA survey

Dark influences

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