On faint companions in the close environment of star-forming dwarf galaxies

Noeske, K. G.; Iglésias-Páramo, J.; Vı́lchez, J. M.; Papaderos, P.; Fricke, K. J.

doi:10.1051/0004-6361:20010446

Cited by 73 publications

(71 citation statements)

References 51 publications

(76 reference statements)

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“…In particular, the conclusions by Taylor et al (1995Taylor et al ( , 1997 on the important role of low-mass companions in triggering SF in "isolated" H iigalaxies are consistent with our data. Similar conclusions are drawn by Noeske et al (2001), based on the environment study of BCGs, mainly from the UM survey. The obtained results do not exclude that some internal mechanisms, which can trigger SF bursts in BCGs, probably work in the minority of them under certain conditions.…”

Section: Results and Types Of Neighbourssupporting

confidence: 81%

Environment status of blue compact galaxies and trigger of star formation

Pustilnik

Kniazev

Lipovetsky

et al. 2001

A&A

112

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Abstract. The work studies of the environment of low-mass galaxies with active star formation (SF) and a possible trigger of SF bursts due to gravitational interaction. Following the study by Taylor et al. (1995), we extend the search for possible disturbing galaxies of various masses to a much larger sample of 86 BCGs from the sky region of the Second Byurakan survey (SBS). The BCG magnitudes and radial velocities are revised and up-dated. The sample under study is separated by the criteria: EW ([Oiii] λ5007 ) > 45Å and V h < 6 000 km sand should be representative of all low-mass galaxies which experience SF bursts. We argue that the moderate tidal disturbers should be taken into account, and incorporate the respective range of distances in the search for disturbing neighbours. The majority of the neighbours in the vicinity of the studied BCGs are found through the study of their environment among UZC (Falco et al. 1999) galaxies, and the follow-up careful search of the fainter galaxies in the NED database. For the remaining BCGs, the neighbouring galaxies are found based on the results of the SAO 6 m telescope spectroscopy. By studing the data on the radial velocities of galaxies in the vicinity of BCGs we found: 1) 33 of the studied BCGs (∼38.5%) are associated with significantly brighter galaxies (∆B ≥ 1.5 m ); 2) 23 BCGs (∼26.5%) have neighbours either of comparable or significantly lower brightness; 3) 14 of the studied BCGs (16%) with no evident associated galaxy are either certain, or probable, mergers. Summarizing, we conclude that in ∼80% (or more) BCGs from the studied sample, the SF bursts are triggered either by tidal action of various strengths from other galaxies, or due to mergers of low-mass galaxies. We briefly discuss the implications of our main conclusion for evolutionary links of BCGs to other types of low-mass galaxies. Part of our sample falls into the volume belonging to the Local Supercluster. Therefore we formulate the results separately on the "Local Supercluster volume" and "general field region". The total fractions of BCGs likely triggered by interaction with other galaxy are respectively, ∼84.5% and 80% for the nearby volume and for the general field. The fractions of BCGs with significantly brighter disturbers in these two groups are seemingly different (∼54±14% vs. ∼31.5±7%, respectively). Among the so called "isolated" BCGs (that is, without a bright neighbouring galaxy) in both the Local Supercluster volume and in general field, ∼43± 10% are probably disturbed by dwarf galaxies and ∼26± 8% have a merger morphology. In the Appendix we present the results of the spectroscopy with the SAO 6 m telescope of 27 galaxies in an attempt to find possible disturbing galaxies in the vicinity of some of the sample BCGs.

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Section: Results and Types Of Neighbourssupporting

confidence: 81%

Environment status of blue compact galaxies and trigger of star formation

Pustilnik

Kniazev

Lipovetsky

et al. 2001

A&A

112

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“…Thus, we conclude that EELGs are located in relative isolation, in agreement with previous findings for local star-forming dwarf galaxies (e.g., Vílchez 1995;Telles & Terlevich 1995;Lee et al 2000;Noeske et al 2001;Pustilnik et al 2001;Koulouridis et al 2013). It should be noted, however, that the fraction of EELGs members of groups is nearly the same as in the SFR-20k sample.…”

Section: The Environment Of Eelgssupporting

confidence: 92%

Extreme emission-line galaxies out toz~ 1 in zCOSMOS

Amorín

Pérez-Montero

Contini

et al. 2015

A&A

Self Cite

102

113

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Context. The study of large and representative samples of low-metallicity star-forming galaxies at different cosmic epochs is of great interest to the detailed understanding of the assembly history and evolution of low-mass galaxies. Aims. We present a thorough characterization of a large sample of 183 extreme emission-line galaxies (EELGs) at redshift 0.11 ≤ z ≤ 0.93 selected from the 20k zCOSMOS bright survey because of their unusually large emission line equivalent widths. Methods. We use multiwavelength COSMOS photometry, HST-ACS I-band imaging, and optical zCOSMOS spectroscopy to derive the main global properties of star-forming EELGs, such as sizes, stellar masses, star formation rates (SFR), and reliable oxygen abundances using both "direct" and "strong-line" methods. Results. The EELGs are extremely compact (r 50 ∼ 1.3 kpc), low-mass (M * ∼ 10 7 −10 10 M ) galaxies forming stars at unusually high specific star formation rates (sSFR ≡ SFR/M up to 10 −7 yr −1 ) compared to main sequence star-forming galaxies of the same stellar mass and redshift. At rest-frame UV wavelengths, the EELGs are luminous and show high surface brightness and include strong Lyα emitters, as revealed by GALEX spectroscopy. We show that zCOSMOS EELGs are high-ionization, low-metallicity systems, with median 12+ log(O/H) = 8.16 ± 0.21 (0.2 Z ) including a handful of extremely metal-deficient (<0.1 Z ) EELGs. While ∼80% of the EELGs show non-axisymmetric morphologies, including clumpy and cometary or tadpole galaxies, we find that ∼29% of them show additional low-surface-brightness features, which strongly suggests recent or ongoing interactions. As star-forming dwarfs in the local Universe, EELGs are most often found in relative isolation. While only very few EELGs belong to compact groups, almost one third of them are found in spectroscopically confirmed loose pairs or triplets. Conclusions. The zCOSMOS EELGs are galaxies caught in a transient and probably early period of their evolution, where they are efficiently building up a significant fraction of their present-day stellar mass in an ongoing, galaxy-wide starburst. Therefore, the EELGs constitute an ideal benchmark for comparison studies between low-and high-redshift low-mass star-forming galaxies.

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“…It is well known that interactions in dwarf galaxies are usual not with nearby giant galaxies (Campos-Aguilar et al 1993;Telles & Terlevich 1995;Telles & Maddox 2000) but with low surface brightness galaxies (Wilcots et al 1996;Noeske et al 2001;Pustilnik et al 2001), or H i clouds (e.g., Taylor et al 1993Taylor et al , 1995Taylor et al , 1996Thuan et al 1999;van Zee et al 2001;Begum et al 2006;Ekta et al 2006;Hutchmeier et al 2008;López-Sánchez & Esteban 2008). Méndez & Esteban (2000) suggested, for the first time, that interactions with or between dwarf objects could be the main star formation triggering mechanism in dwarf galaxies.…”

Section: Quantification Of the Interaction Featuresmentioning

confidence: 99%

Massive star formation in Wolf-Rayet galaxies

López-Sánchez

2010

A&A

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Aims. We performed a comprehensive 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 galaxies. Methods. In this paper, the last in the series, we analyze the global properties of our galaxy sample using multiwavelength data extracted from our own observations (Hα fluxes, B and H-band magnitudes) and from the literature, which include X-ray, FUV, FIR, and radio (both H i spectral line and 1.4 GHz radio-continuum) measurements.Results. The agreement between our Hα-based star-formation rates (Sfr) and those provided by indicators at other wavelengths is remarkable, but we consider that the new Hα-based calibration provided by Calzetti et al. (2007, ApJ, 666, 870) should be preferred to older calibrations. The FUV-based Sfr provides a powerful tool for analyzing the star-formation activity on both global and local scales independently to the Hα emission. We provide empirical relationships between the ionized gas mass, neutral gas mass, dust mass, stellar mass, and dynamical mass with the B-luminosity. Although all mass estimations increase with increasing luminosity, we find important deviations to the general trend in some objects, which seem to be the consequence of their particular evolutionary histories. The analysis of the mass-to-light ratios give similar results. We investigate the mass-metallicity relations and conclude that both the nature and the star-formation history are needed to understand the relationships between both properties. The majority of the galaxies follow a Schmidt-Kennicutt scaling law of star-formation that agrees with that reported in individual star-forming regions within M 51 but not with that found in normal spiral galaxies. Dwarf galaxies seem to be forming stars more efficiently than the outskirts of spiral galaxies. We find a relation between the reddening coefficient and the warm dust mass indicating that the extinction is mainly internal to the galaxies. The comparison with the closed-box model also indicates that the environment has strongly affected their evolution. Conclusions. Considering all multiwavelength data, we found that 17 up to 20 galaxies are clearly interacting or merging with lowluminosity dwarf objects or H i clouds. The remaining three galaxies (Mkn 5, SBS 1054+364, and SBS 1415+437) show considerable divergences of some properties when comparing with similar objects. Many of the interacting/merging features are only detected when deep optical spectroscopy and a detailed multiwavelength analysis, including H i observations, are obtained. We conclude that interactions do play a fundamental role in the triggering mechanism of the strong star-formation activity observed in dwarf starburst galaxies.

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On faint companions in the close environment of star-forming dwarf galaxies

Cited by 73 publications

References 51 publications

Environment status of blue compact galaxies and trigger of star formation

Environment status of blue compact galaxies and trigger of star formation

Extreme emission-line galaxies out toz~ 1 in zCOSMOS

Massive star formation in Wolf-Rayet galaxies

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