On the Neutral Gas Content and Environment of NGC 3109 and the Antlia Dwarf Galaxy

Barnes, David G.; Blok, W. J. G. de

doi:10.1086/321170

Cited by 42 publications

(64 citation statements)

References 37 publications

(56 reference statements)

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“…The dIrr/dSph galaxy Antlia is a close (!40 kpc) companion of the more massive, gas-rich dIrr NGC 3109 (van den Bergh 1999b). Antlia appears to have had a close encounter with NGC 3109 about 1 Gyr ago, which caused a warp in the disk of NGC 3109 (Barnes & de Blok 2001). It now has a low H i mass of $7 Â 10 5 M .…”

Section: Tidal Stripping In Progress?mentioning

confidence: 99%

“…H i masses were recalculated from the integrated flux density or from upper limits assuming a uniform H i column density within the tidal radius (x 2.2), using the updated heliocentric distances given above. Other references: Sgr: Koribalski, Johnston, & Otrupcek (1994, assuming an angular size of 10 Â 4 ); LMC: Kim et al 1998;SMC: Stanimirović et al 1999;UMi, Dra, Sex, Leo I: Young 2000;For, Leo II: Young 1999;Car: Mould et al 1990; Scl, And II, And III, And V, And VI, Cas dSph, DDO 210, LGS 3, Peg DIG: Blitz & Robishaw 2000;And I: Thuan & Martin 1979;Cet: Huchtmeier et al 2001;Phe: St-Germain et al 1999;Tuc: Oosterloo et al 1996; Ant: Barnes & de Blok 2001;KKR 25: Karachentsev et al 2001; for the remainder.…”

Section: The Nearby Dwarf Galaxy Samplementioning

confidence: 99%

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The Progenitors of Dwarf Spheroidal Galaxies

Grebel¹,

Gallagher²,

Harbeck³

2003

The Astronomical Journal

481

702

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The gas-deficient dwarf spheroidal (dSph) galaxies present an evolutionary puzzle that we explore in 40 early-type and late-type dwarfs in the Local Group and nearby field. Although dSph's experienced star formation over extended time spans in their youths, today all but one are completely free of detectable interstellar material, even in the Fornax dSph, where stars formed in the last 100 Myr. Combining photometric and spectroscopic stellar metallicity estimates for red giant branches with high-sensitivity H i 21 cm line data from the literature, we show that the well-established offset in luminosity-metallicity relationships for dSph's and dwarf irregular (dIrr) galaxies exists also when confining the comparison to their old stellar populations: dSph's have higher mean stellar metallicities for a fixed optical luminosity. Evidently star formation in younger dSph's was more vigorous than in the youthful dIrr's, leading to more efficient enrichment. Dwarf galaxies, whose locus in the luminosity-metallicity diagram is consistent with that of dSph's, even when baryonic luminosities are considered, are the '' transition-type dwarfs '' Phoenix, DDO 210, LGS 3, Antlia, and KKR 25. These dwarfs have mixed dIrr/dSph morphologies, low stellar masses, low angular momentum, and H i contents of at most a few 10 6 M . Unlike dIrr's many transition-type dwarfs would closely resemble dSph's if their gas were removed, as required to become a dSph; they are likely dSph progenitors. As gas removal is the key factor for such a transition, we consider the empirical evidence in favor and against various gas removal processes. We suggest that internal gas removal mechanisms are inadequate and favor ram-pressure stripping to clean the bulk of interstellar matter from galaxies to make dSph's. A combination of initial conditions and environment seems to support the formation of dSph's: nearby dSph's appear to form from small galaxies with active early star formation, whose evolution halts due to externally induced gas loss. Transition-type dwarfs, then, are dSph's that kept their interstellar medium and therefore should replace dSph's in isolated locations where stripping is ineffective.

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Section: Tidal Stripping In Progress?mentioning

confidence: 99%

Section: The Nearby Dwarf Galaxy Samplementioning

confidence: 99%

The Progenitors of Dwarf Spheroidal Galaxies

Grebel¹,

Gallagher²,

Harbeck³

2003

The Astronomical Journal

481

702

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“…In this regard, the natural comparison to NGC 6822 is NGC 3109, a galaxy of the same morphological type. In both galaxies, de Blok & Walter (2000) and Barnes & de Blok (2001) have recently mapped extensive HI envelopes.…”

Section: Introductionmentioning

confidence: 99%

Carbon star survey in the Local Group

Demers¹,

Battinelli²,

Letarte³

2003

A&A

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Abstract. We present a CFH12K wide field survey of the carbon star population in and around NGC 3109. Carbon stars, the brightest members of the intermediate-age population, were found nearly exclusively in and near the disk of NGC 3109, ruling out the existence of an extensive intermediate-age halo like the one found in NGC 6822. Over 400 carbon stars identified have M I = −4.71, confirming the nearly universality of mean magnitude of C star populations in Local Group galaxies. Star counts over the field reveal that NGC 3109 is a truncated disk shaped galaxy without an extensive stellar halo. The minor axis star counts reach the foreground density between 4 and 5 , a distance that can be explained by an inclined disk rather than a spheroidal halo. We calculate a global C/M ratio of 1.75 ± 0.20, a value expected for such a metal poor galaxy.

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“…The peri-Galactic passage was not only the time when the tidal strain of the MW was maximum on each individual member of the association, but also the epoch when the members were most closely packed together, maximizing the effects and the probability of dwarf-to-dwarf interactions. It seems likely that the tidal tails of Antlia and Sex A, as well as the warp and substructures observed in NGC 3109 (Hidalgo et al 2008;Barnes & de Blok 2001;Dalcanton et al 2009) were produced during that relatively short epoch of multiple interactions.…”

mentioning

confidence: 99%

The extended structure of the dwarf irregular galaxies Sextans A and Sextans B

Bellazzini

Beccari

Fraternali

et al. 2014

A&A

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We present a detailed study of the stellar and H  structure of the dwarf irregular galaxies Sextans A and Sextans B, members of the NGC 3109 association. We use newly obtained deep (r 26.5) and wide-field g and r photometry to extend the surface brightness (SB) profiles of the two galaxies down to µ V 31.0 mag/arcsec 2 . We find that both galaxies are significantly more extended than previously traced with surface photometry, out to ∼ 4 kpc from their centres along their major axes. Older stars are found to have more extended distribution than younger populations. We obtain the first estimate of the mean metallicity for the old stars in Sex B, from the colour distribution of the red giant branch, [Fe/H] = −1.6. The SB profiles show significant changes of slope and cannot be fitted with a single Sérsic model. Both galaxies have HI discs as massive as their respective stellar components. In both cases the H  discs display solid-body rotation with maximum amplitude of ∼50 km s −1 (albeit with significant uncertainty due to the poorly constrained inclination), implying a dynamical mass ∼10 9 M , a mass-to-light ratio∼ 25, and a dark-to-baryonic mass ratio of ∼10. The distribution of the stellar components is more extended than the gaseous disc in both galaxies. We find that the main, approximately round, stellar body of Sex A is surrounded by an elongated low-SB stellar halo that can be interpreted as a tidal tail, similar to that found in another member of the same association (Antlia). We discuss these, as well as other evidence of tidal disturbance, in the framework of a past passage of the NGC 3109 association close to the Milky Way, which has been hypothesised by several authors and is also supported by the recently discovered filamentary configuration of the association itself.

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On the Neutral Gas Content and Environment of NGC 3109 and the Antlia Dwarf Galaxy

Cited by 42 publications

References 37 publications

The Progenitors of Dwarf Spheroidal Galaxies

The Progenitors of Dwarf Spheroidal Galaxies

Carbon star survey in the Local Group

The extended structure of the dwarf irregular galaxies Sextans A and Sextans B

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