Abstract
We used K-band photometry, maximum rotational velocities derived from Fabry-Perot data and HI observed and predicted masses to study, for the first time, the K-band, stellar and baryonic Tully-Fisher relations for galaxies in Hickson compact groups. We compared these relations with the ones defined for galaxies in less dense environments from the GHASP survey and from a sample of gas-rich galaxies. We find that most of the Hickson compact group galaxies lie on the K-band Tully-Fisher relation defined by field galaxies with a few low-mass outliers, namely HCG 49b and HCG 96c, which appear to have had strong recent burst of star formation. The stellar Tully-Fisher relation for compact group galaxies presents a similar dispersion to that of the K-band relation, and it has no significant outliers when a proper computation of the stellar mass is done for the strongly star-forming galaxies. The scatter in these relations can be reduced if the gaseous component is taken into account, i.e., if a baryonic Tully-Fisher relation is considered. In order to explain the positions of the galaxies off the K-band Tully-Fisher relation we favour a scenario in which their luminosities are brightened due to strong star formation or AGN activity. We argue that strong bursts of star formation can affect the B and K-band luminosities of HCG 49b and HCG 96c and in the case of the latter also AGN activity may affect the K-band magnitude considerably, without affecting their total masses.
Highlights
There has been increased interest in the past few years in the use of the Tully–Fisher (TF) relation as a means of quantifying galaxy evolution as a function of redshift
We find that the stellar TF relation for the HCG sample presents a larger dispersion than the relation defined for the Gassendi HAlpha survey of Spirals (GHASP) sample, which has a dispersion factor of 0.31 dex in the stellar mass
Using this value and the already published stellar mass of HCG 96c, we found that these K-band TF outlier galaxies lie on the stellar and baryonic TF relations defined by field galaxies
Summary
There has been increased interest in the past few years in the use of the Tully–Fisher (TF) relation as a means of quantifying galaxy evolution as a function of redshift. As shown in Mendes de Oliveira et al (2003) and Torres-Flores et al (2010), most of the HCG galaxies lie on the B-band TF relation, with a few low-mass outliers. We attempt to find possible explanations for the location of the outlying positions of the low-mass galaxies in the B-band compact group TF relation (Mendes de Oliveira et al 2003; Torres-Flores et al 2010). We have used a sample of non-interacting galaxies from the Gassendi HAlpha survey of Spirals (GHASP), for which the BTF relation has been recently studied by Torres-Flores et al (2011). These authors found that the BTF relation for the GHASP sample is in agreement with cosmological predictions (e.g. Bullock et al 2001).
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