Neutral Hydrogen Studies of Galaxies with a Single-Spacing Interferometer

Rogstad, D. H.; Rougoor, G. W.; Whiteoak, J. B.

doi:10.1086/149309

Cited by 21 publications

(5 citation statements)

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“…This is in good agreement with previously published values, e.g. −130 km s −1 (Rogstad, Rougoor & Whiteoak 1967) and −116 km s −1 (Huchra et al 1993). The flux‐weighted mean velocity is (−119 ± 2) km s −1 , and the peak flux is detected at −112 km s −1 .…”

Section: Resultssupporting

confidence: 94%

The neutral hydrogen environments of the nearby galaxies WLM, NGC 1313 and Sextans A

Barnes¹,

Blok²

2004

Monthly Notices of the Royal Astronomical Society

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We have mapped the neutral gas content of the surroundings of three galaxies on the outskirts of the Local Group -Wolf-Lundmark-Melotte (WLM), NGC 1313 and Sextans A -at high velocity resolution and brightness sensitivity. We present high-quality H I spectra and parameters for the target galaxies, and find no unknown companion H I clouds nearer than ∼100 kpc to the targets, despite reaching a sensitivity of ∼10 6 M for narrow-linewidth objects.

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Section: Resultssupporting

confidence: 94%

The neutral hydrogen environments of the nearby galaxies WLM, NGC 1313 and Sextans A

Barnes¹,

Blok²

2004

Monthly Notices of the Royal Astronomical Society

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“…In neither M82 nor NGC 1808 does the atomic gas form a symmetrical distribution on the scale of that seen around NGC 4490. NGC 4449, however, does closely resemble NGC 4490: the atomic gas associated with NGC 4449 extends to ∼14 times the optical diameter (Hunter et al 1998; Bajaja, Huchtmeier & Klein 1994; Rogstad, Rougoor & Whiteoak 1967). NGC 4449 is a Magellanic Dwarf with a filamentary H α structure and extended soft X‐ray (Della Ceca, Griffiths & Heckman 1997) and radio continuum (Klein et al 1996) halo.…”

Section: Discussionmentioning

confidence: 99%

Hα, SCUBA and MERLIN imaging of NGC 4490

Clemens

Alexander

2002

Monthly Notices of the Royal Astronomical Society

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We describe Hα, SCUBA and MERLIN imaging of the interacting galaxy pair NGC 4490 and 4485. We detect an Hα filament emerging from the disc of NGC 4490 to a projected distance of 3 kpc which has counterparts in both the radio continuum and H i. The H i counterpart extends to a projected distance of ∼30 kpc from NGC 4490 and we argue that this is evidence that the giant H i envelope in this system has its origins in star formation. We use SCUBA and radio continuum data to attempt to place constraints on the distribution of dust with respect to the star forming regions. This analysis is limited by the lack of an independent estimate of the dust temperature, something that both ‘SIRTF’ and ‘SOFIA’ will be able to provide, however we find some evidence that most obscuring dust is not located within H ii regions themselves.

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“…The CO spectrum shows an absorption signature near 0 km s −1 due to Galactic foreground CO emission in the reference beam. Rogstad et al (1967) obtained an HI spectrum towards NGC 1569 which shows HI emission at ∼ −90 km s −1 , and also detected a narrow emission feature at ∼ 0 km s −1 from the Galaxy. The two features are well separated so there should not be any contamination from the off-beam reference position affecting the line profile.…”

Section: Data Reductionmentioning

confidence: 95%

CO Emission in Low-Luminosity, H [CSC]i[/CSC]–rich Galaxies

Taylor

Kobulnicky

Skillman

1998

The Astronomical Journal

164

195

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We present 12 CO 1 → 0 observations of eleven low luminosity (M B > −18), HI-rich dwarf galaxies. Only the three most metal-rich galaxies, with 12+log(O/H)≈ 8.2, are detected. Very deep CO spectra of six extremely metal-poor systems (12+log(O/H)≤7.5) yield only low upper limits on the CO surface brightness, I CO < 0.1 K km s −1 . Three of these six have never before been observed in a CO line, while the others now have much more stringent upper limits. For the very low metallicity galaxy Leo A, we do not confirm a previously reported detection in CO, and the limits are consistent with another recent nondetection.We combine these new observations with data from the literature to form a sample of dwarf galaxies which all have CO observations and measured oxygen abundances. No known galaxies with 12+log(O/H)<7.9 (Z < 0.1Z ⊙ ) have been detected in CO. Most of the star-forming galaxies with higher (12+log(O/H)>8.1) metallicities are detected at similar or higher I CO surface brightnesses. The data are consistent with a strong dependence of the I CO /M H 2 ≡ X CO conversion factor on ambient metallicity. The strikingly low upper limits on some metal-poor galaxies lead us to predict that the conversion factor is non-linear, increasing sharply below ∼1/10 of the solar metallicity (12+log(O/H)≤7.9).

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Neutral Hydrogen Studies of Galaxies with a Single-Spacing Interferometer

Cited by 21 publications

References 0 publications

The neutral hydrogen environments of the nearby galaxies WLM, NGC 1313 and Sextans A

The neutral hydrogen environments of the nearby galaxies WLM, NGC 1313 and Sextans A

Hα, SCUBA and MERLIN imaging of NGC 4490

CO Emission in Low-Luminosity, H [CSC]i[/CSC]–rich Galaxies

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