Radio continuum and far-infrared observations of low surface brightness galaxies

Hoeppe, Götz; Brinks, E.; Klein, U.; Giovanardi, C.; Altschuler, Daniel R.; Price, R. M.; Deeg, H. J.

doi:10.1086/117082

Cited by 13 publications

(12 citation statements)

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“…It has a 20 cm continuum flux of only 5 mJy in the NVSS data (Condon et al 1998), low compared to other dwarf galaxies with measured 20 cm fluxes (e.g. Höppe et al 1994;Klein et al 1991), suggesting a high X CO . The non-detection of CO is thus not unexpected.…”

Section: Discussionmentioning

confidence: 86%

A search for CO in the Local Group dwarf irregular galaxy WLM

Taylor

Klein

2001

A&A

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Abstract. We present 12 CO J = 1 → 0 and J = 2 → 1 observations of the low metallicity (12 + log(O/H) = 7.74) Local Group dwarf irregular galaxy WLM made with the 15 m SEST and 14 m FCRAO telescopes. Despite the presence a number of HII regions, we find no CO emission. We obtain low upper limits on the integrated intensity (ICO ≤ 0.18 K km s −1 for CO (1 → 0)). The non-detection is consistent with the result of Taylor, Kobulnicky & Skillman (1998), that dwarf galaxies below a metallicity of ∼7.9 are not detected in CO emission. WLM shows that this trend continues for low metallicity galaxies even as their metallicities approach 7.9. These results are consistent with the models of the metal poor ISM by Norman & Spaans (1997). By comparing our CO data with observations of star formation in WLM, we find evidence for a high CO to H2 conversion factor.

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Section: Discussionmentioning

confidence: 86%

A search for CO in the Local Group dwarf irregular galaxy WLM

Taylor

Klein

2001

A&A

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“…Applying only foreground extinction from the galaxy gives reasonable results for the LSB galaxies, since internal extinction can be neglected for these galaxies due to the low dust content. There exists only a few week detections for LSB galaxies in the FIR and mm-wavelength region where dust radiates thermal emission (Hoeppe et al 1994). The final result of the reduction and calibration processes are 2D-and 1D-spectra which will be used in the following analysis.…”

Section: Reduction and Calibrationmentioning

confidence: 99%

“…The suppression of the U-flux due to a large amount of dust could also be excluded. Until now only a few detections of LSB galaxies in the FIR wavelength region at very low levels exist (Hoeppe et al 1994).…”

Section: Conclusion and Summarymentioning

confidence: 99%

Low surface brightness galaxies around the HDF-S

Haberzettl

Bomans

Dettmar

2007

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Aims. With this study we aim at the spectroscopic verification of a photometrically selected sample of Low Surface Brightness (LSB) galaxy candidates in a field around the Hubble Deep Field-South (HDF-S). The sample helps to extend the parameter space for LSB galaxies to lower central surface brightnesses and to provide better estimates on the volume densities of these objects. Methods. To derive redshifts for the LSB candidates, long-slit spectra were obtained covering a spectral range from 3400 Å to 7500 Å. The observations have been obtained using the ESO 3.6 m telescope, equipped with the EFOSC2 spectrograph. From the measured radial velocities, distances could be estimated. With this distance information, it is possible to differentiate between true LSB galaxies and higher redshift High Surface Brightness (HSB) galaxies which may contaminate the sample. A correction for the surface brightnesses can then be applied, accounting for the cosmological dimming effect ("Tolman Dimming"). Results. We show that ∼70% of the LSB candidates, selected based on their location in the color−color space, are real LSB galaxies. Their position in the color−color diagrams, therefore, indicate that the LSB galaxies have a different stellar population mix resulting from a different star formation history compared to HSBs. Our LSB galaxy sample consists only of large disk galaxies with scalelength between 2.5 kpc and 7.3 kpc. We confirm the flat central surface brightness distribution of previous surveys and extend this distribution down to central surface brightnesses of 27 B mag arcsec −2 .Key words. surveys -galaxies: distances and redshifts -galaxies: fundamental parameters IntroductionThe known properties of LSB galaxies are still a challenge for existing theories of galaxy formation and evolution. Although they may not represent a significant amount of the luminosity density in the universe, their number density is very high. Searches for LSB galaxies showed that they account for up to 60% of the local galaxy population (McGaugh 1996;O'Neil & Bothun 2000). Minchin et al. (2004) showed in their study of the bivariate surface brightness distribution, that up to 20% of the dynamical mass is represented by the LSB galaxies and that they account for up to 60% of the number density in the Universe. Thus it seems, that LSB galaxies are a common product of galaxy formation and evolutionary processes. Therefore, it is essential to understand their role in formation and evolution scenarios of galaxies in general. Studies of the properties of local LSB galaxy samples have shown that they populate nearly the whole parameter space derived also for HSB galaxies. The only difference is their low central surface brightness which is below µ 0 = 22.5 mag arcsec −2 in the B-filter. Field LSB galaxies are generally gas rich, although the gas surface densities are very low, too. The typical gas surface densities for LSB galaxies are below the Kennicutt criterion for ongoing star formation (Kennicutt 1989;van der Hulst et al. 1993;Picker...

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“…Hoeppe et al 1994). The sensitivity of our continuum maps is determined by the effective bandwidth used, i.e.…”

Section: Radio Continuum Emission From Dwarf Galaxiesmentioning

confidence: 99%