Spectrophotometry of 83 possible blue compact dwarf galaxies from the second byurakan survey

Izotov, Y. I.; Lipovetsky, V. A.; Гусева, Н. Г.; Kniazev, A. Y.; Neizvestny, S. I.; Stepanian, J. A.

doi:10.1080/10556799308230561

Cited by 18 publications

(20 citation statements)

References 19 publications

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“…The latter is partly described by Izotov et al (1993), Thuan et al (1994), Pustilnik et al (1995). The same BCG sample was in particular the subject of an HI-study by Thuan et al (1999).…”

Section: Bcg Samplementioning

confidence: 85%

Environment status of blue compact galaxies and trigger of star formation

Pustilnik

Kniazev

Lipovetsky

et al. 2001

A&A

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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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“…The latter is partly described by Izotov et al (1993), Thuan et al (1994), Pustilnik et al (1995). The same BCG sample was in particular the subject of an HI-study by Thuan et al (1999).…”

Section: Bcg Samplementioning

confidence: 85%

Environment status of blue compact galaxies and trigger of star formation

Pustilnik

Kniazev

Lipovetsky

et al. 2001

A&A

Self Cite

112

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“…• (Izotov et al 1993a(Izotov et al , 1993bPustilnik et al 1995) and Case survey: RA = 8 h 00 m to 16 h 10 m , Dec = +29…”

Section: Sample Descriptionmentioning

confidence: 99%

Studies of galaxies in voids

Pustilnik¹,

Martin²,

Huchtmeier³

et al. 2002

A&A

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Abstract. We present here results of studies of the properties of galaxies located in very low density environments. We observed 26 blue compact galaxies (BCGs) from the Second Byurakan (SBS) and Case surveys located in voids with the radial velocities V hel . 11 000 km s −1 , two BCGs in the void behind the Virgo cluster and 11 BCGs in denser environments. H i fluxes and profile widths, as well as estimates of total H i masses, are presented for the 27 detected galaxies (of which 6 are in three galaxy pairs and are not resolved by the radiotelescope beam). Preliminary comparisons of void BCGs with similar objects from intermediate density regions -in the general field and the Local Supercluster (sub-samples of BCGs in the SBS zone) and in the dense environment of the Virgo Cluster (a BCD sample) -are performed using the hydrogen-to-blue-luminosity ratio M (H i)/LB. We find that for the same blue luminosity, for MB > −18. m 0, BCGs in lower density environment have on average more H i. The slope β of the M (H i)/LB _ L β for BCGs shows a trend of steepening with decreasing bright galaxy density, being very close to zero for the densest environment considered here and reaching β = −0.4 for voids.

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“…Their characteristic range of metallicity Z is ∼(1/15−1/3) Z (e.g., Terlevich et al 1991;Izotov et al 1993), while very few of them show Z as low as (1/50−1/20) Z . All well-studied BCGs with characteristic metallicities were found to be old galaxies, which evolve slower than their massive counterparts.…”

Section: Introductionmentioning

confidence: 99%

The Hamburg/SAO Survey for low metallicity blue compact H II galaxies (HSS–LM)

Ugryumov

Engels

Pustilnik

et al. 2002

A&A

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Abstract. We present the description and the first results of a new project devoted to the search for extremely metaldeficient blue compact/H -galaxies (BCGs) and to the creation of a well selected large BCG sample with strong emission lines. Such galaxies should be suitable for reliable determination of their oxygen abundance through the measurement of the faint [O ] λ 4363 Å line. The goals of the project are two-fold: a) to discover a significant number of new extremely metalpoor galaxies (Z 1/20 Z ), and b) to study the metallicity distribution of local BCGs. Selection of candidates for follow-up slit spectroscopy is performed on the database of objective prism spectra of the Hamburg Quasar Survey. The sky region is limited by δ ≥ 0• and b II ≤ −30• . In this paper we present the results of the follow-up spectroscopy conducted with the Russian 6 m telescope. The list of observed candidates contained 52 objects, of which 46 were confirmed as strong-lined BCGs (EW([O ] λ 5007) ≥ 100 Å). The remaining five lower excitation ELGs include three BCGs, and two galaxies classified as SBN (Starburst Nucleus) and DANS (Dwarf Amorphous Nucleus Starburst). One object is identified as a quasar with a strong Lyα emission line near λ 5000 Å (z ∼ 3). We provide a list with coordinates, measured radial velocities, B-magnitudes, equivalent widths EW([O ] λ 5007) and EW(Hβ) and for the 46 strong-lined BCGs the derived oxygen abundances 12+log(O/H). The abundances range between 7.42 and 8.4 (corresponding to metallicities between 1/30 and 1/3 Z ). The sample contains four galaxies with Z 1/20 Z , of which three are new discoveries. This demonstrates the high efficiency of the new project to find extremely metal-deficient galaxies. The radial velocities of the strong-lined ELGs range between 500 and 19 000 km s −1 with a median value of ∼6400 km s −1 . The typical B-magnitudes of the galaxies presented are 17. m 0−18. m 0.

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Spectrophotometry of 83 possible blue compact dwarf galaxies from the second byurakan survey

Cited by 18 publications

References 19 publications

Environment status of blue compact galaxies and trigger of star formation

Environment status of blue compact galaxies and trigger of star formation

Studies of galaxies in voids

The Hamburg/SAO Survey for low metallicity blue compact H II galaxies (HSS–LM)

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