Kinematics, substructure and luminosity-weighted dynamics of six nearby galaxy groups

Firth, P.; Evstigneeva, E. A.; Jones, Bryn; Drinkwater, Michael J.; Phillipps, S.; Gregg, Michael D.

doi:10.1111/j.1365-2966.2006.10993.x

Cited by 39 publications

(73 citation statements)

References 25 publications

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“…We derived the kinematical and dynamical properties of our three groups, following the luminosity-weighted approach described in Firth et al (2006). This approach allow us to describe in an homogeneous way the properties of our groups and to compare them with that of nearby groups.…”

Section: Group Kinematic and Luminosity-weighted Dynamical Propertiesmentioning

confidence: 99%

“…This approach allow us to describe in an homogeneous way the properties of our groups and to compare them with that of nearby groups. Firth et al (2006) analysis considered six nearby groups having a central dominant galaxy and broad density range. These groups have both spiral and early-type members as dominant galaxies.…”

Section: Group Kinematic and Luminosity-weighted Dynamical Propertiesmentioning

confidence: 99%

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Galaxy evolution in Local Group analogs

Marino

Bianchi

Rampazzo

et al. 2010

A&A

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Context. Understanding the astrophysical processes acting within galaxy groups and their effects on the evolution of the galaxy population is one of the crucial topics of modern cosmology, as almost 60% of galaxies in the Local Universe are found in groups. Aims. We aim at learning about galaxy evolution within nearby groups dominated by late-type galaxies, specifically by studying their ultraviolet-emitting stellar population. Methods. We imaged in the far (FUV, λ eff = 1539 Å) and near ultraviolet (NUV, λ eff = 2316 Å) with the Galaxy Evolution Explorer (GALEX) three nearby groups, namely LGG 93, LGG 127 and LGG 225. We obtained the UV galaxy surface photometry and, for LGG 225, the only group covered by the SDSS, the photometry in u, g, r, i, z bands. We discuss galaxy morphologies looking for interaction signatures and we analyze the spectral energy distribution of galaxies to infer their luminosity-weighted ages. The UV and optical photometry was also used to perform a luminosity-weighted kinematical and dynamical analysis of each group and to evaluate the stellar mass. Results. A few member galaxies in LGG 225 show a distorted UV morphology due to ongoing interactions. (FUV − NUV) colors suggest that spirals in LGG 93 and LGG 225 host stellar populations in their outskirts younger than that of M 31 and M 33 in the Local Group or with less extinction. The irregular interacting galaxy NGC 3447A has a significantly younger stellar population (a few Myr old) than the average of the other irregular galaxies in LGG 225 suggesting that the encounter triggered star formation. The early-type members of LGG 225, NGC 3457 and NGC 3522, have masses of the order of a few 10 9 M , comparable to the Local Group ellipticals. For the most massive spiral in LGG 225, we estimate a stellar mass of ≈4 × 10 10 M , comparable to M 33 in the Local Group. Ages of stellar populations range from a few to ≈7 Gyr for the galaxies in LGG 225. The kinematical and dynamical analysis indicates that LGG 127 and LGG 225 are in a pre-virial collapse phase, i.e. still undergoing dynamical relaxation, while LGG 93 is likely virialized. Both the photometric and the dynamical analyses suggest that LGG 225 is in a more active evolution phase than LGG 93 and LGG 127.

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Section: Group Kinematic and Luminosity-weighted Dynamical Propertiesmentioning

confidence: 99%

Section: Group Kinematic and Luminosity-weighted Dynamical Propertiesmentioning

confidence: 99%

Galaxy evolution in Local Group analogs

Marino

Bianchi

Rampazzo

et al. 2010

A&A

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“…According to Firth et al (2006), unaccounted dwarf galaxies do not significantly alter the group velocity dispersions, virial mass estimates or crossing times. The dynamical calculations are based on the formulae given in Firth et al (2006, their Table 6).…”

Section: Kinematic and Dynamical Properties Of U268 And U376mentioning

confidence: 99%

“…c Uncertainties are ≈ 0.02 Gyrs. We derived the kinematic and dynamical properties of the two groups, following the approach described in Firth et al (2006) and already used in Marino et al (2010) for LGG 225. This approach allows us to obtain in an homogeneous way the properties of the two groups and to compare them with those of nearby groups.…”

Section: Kinematic and Dynamical Properties Of U268 And U376mentioning

confidence: 99%

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Galaxy evolution in groups. USGC U268 and USGC U376 in the Leo cloud

Marino¹,

Bianchi²,

Mazzei³

et al. 2014

Advances in Space Research

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With the aim of investigating galaxy evolution in nearby galaxy groups, we analysed the spectral energy distribution of 24 galaxies, members of two groups in the Leo cloud, USGC U268 and USGC U376. We estimated the ages and stellar masses of the galaxies by fitting their total apparent magnitudes from far-ultraviolet to near-infrared with population synthesis models. The comparison of the results for a subsample of galaxies with smooth particle hydrodynamic (SPH) simulations with chemo-photometric implementation, shows that in most cases the estimated stellar masses obtained with the two different approaches are in good agreement. The kinematical and dynamical analysis indicates that USGC U268 is in a pre-virial collapse phase while USGC U376 is likely in a more evolved phase towards virialization.

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