Integrated spectroscopy of bulge globular clusters and fields

Maraston, Claudia; Greggio, L.; Renzini, A.; Ortolani, S.; Saglia, R.; Puzia, Thomas H.; Kissler-Patig, M.

doi:10.1051/0004-6361:20021723

Cited by 112 publications

(190 citation statements)

References 82 publications

Supporting

Mentioning

179

Contrasting

Unclassified

Order By: Relevance

“…11. The models of Maraston (1998) and Maraston et al (2003) are shown as dot-dashed lines, and a few ages of the single stellar population are indicated. EDCSNJ1354025-1232300 z=0.7576 T=3 Fig.…”

Section: Blue-sequence Galaxiesmentioning

confidence: 99%

See 1 more Smart Citation

Disc colours in field and cluster spiral galaxies at 0.5 ≲z≲ 0.8

Cantale

Jablonka

Courbin

et al. 2016

A&A

View full text Add to dashboard Cite

We present a detailed study of the colours of late-type galaxy discs for ten of the EDisCS galaxy clusters with 0.5 z 0.8. Our cluster sample contains 172 spiral galaxies, and our control sample is composed of 96 field disc galaxies. We deconvolved their ground-based V and I images obtained with FORS2 at the VLT with initial spatial resolutions between 0.4 and 0.8 arcsec to achieve a final resolution of 0.1 arcsec with 0.05 arcsec pixels, which is close to the resolution of the ACS at the HST. After removing the central region of each galaxy to avoid pollution by the bulges, we measured the V − I colours of the discs. We find that 50% of cluster spiral galaxies have disc V − I colours redder by more than 1σ of the mean colours of their field counterparts. This is well above the 16% expected for a normal distribution centred on the field disc properties. The prominence of galaxies with red discs depends neither on the mass of their parent cluster nor on the distance of the galaxies to the cluster cores. Passive spiral galaxies constitute 20% of our sample. These systems are not abnormally dusty. They are are made of old stars and are located on the cluster red sequences. Another 24% of our sample is composed of galaxies that are still active and star forming, but less so than galaxies with similar morphologies in the field. These galaxies are naturally located in the blue sequence of their parent cluster colour-magnitude diagrams. The reddest of the discs in clusters must have stopped forming stars more than ∼5 Gyr ago. Some of them are found among infalling galaxies, suggesting preprocessing. Our results confirm that galaxies are able to continue forming stars for some significant period of time after being accreted into clusters, and suggest that star formation can decline on seemingly long (1 to 5 Gyr) timescales.

show abstract

Section: Blue-sequence Galaxiesmentioning

confidence: 99%

“…10 the evolutionary tracks of star clusters in the (U − V, V − J) plane as provided by the models of Maraston (1998) and Maraston et al (2003). We carefully calibrated the zeropoints of these models against the observations of globular clusters of Frogel et al (1980) and Bica & Alloin (1986a).…”

Section: Blue-sequence Galaxiesmentioning

confidence: 99%

Disc colours in field and cluster spiral galaxies at 0.5 ≲z≲ 0.8

Cantale

Jablonka

Courbin

et al. 2016

A&A

View full text Add to dashboard Cite

show abstract

“…Hence, this approximation does not account for the temperature and gravity sensitivity of the indices, which causes significant deviations from the giant-turnoffdwarf ratio quoted above. For instance, as shown in Maraston et al (2003), in a 15 Gyr old stellar population with solar metallicity, the dwarfs do contribute 20 per cent to the final Mg index, despite the low continuum flux. This contribution even increases to 60 per cent in the most metal-poor case.…”

Section: Hδa -Ps02mentioning

confidence: 86%

Rejuvenation of spiral bulges

Thomas

Davies

2007

Proc. IAU

View full text Add to dashboard Cite

We seek to understand whether the stellar populations of galactic bulges show evidence of secular evolution triggered by the presence of the disc. For this purpose we re-analyse the sample of Proctor and Sansom, deriving stellar population ages and element abundances from absorption line indices as functions of central velocity dispersion and Hubble type. We obtain consistent constraints on ages from the three Balmer line indices Hβ, Hγ, and Hδ, based on stellar population models that take the abundance ratio effects on these indices into account. Emission line contamination turns out to be a critical aspect, which favours the use of the higher-order Balmer line indices. Our derived ages are consistent with those of Proctor and Sansom based on a completely different method. In agreement with other studies in the literature, we find that bulges have relatively low luminosity weighted ages, the lowest age derived being 1.3 Gyr. Hence bulges are not generally old, but actually rejuvenated systems. We discuss evidence that this might be true also for the bulge of the Milky Way. The data reveal clear correlations of all three parameters luminosity weighted age, total metallicity, and α/Fe ratio with central velocity dispersion. The smallest bulges are the youngest with the lowest α/Fe ratios owing to late Fe enrichment from Type Ia supernovae. Using models combining recent minor star formation with a base old population, we show that the smallest bulges must have experienced significant star formation events involving 10 − 30 per cent of their total mass in the past 1 − 2 Gyr. No significant correlations of the stellar population parameters with Hubble Type are found. We show that the above relationships with σ coincide perfectly with those of early-type galaxies. In other words, bulges are typically younger, metal-poorer and less α/Fe enhanced than early-type galaxies, because of their smaller masses. At a given velocity dispersion, bulges and elliptical galaxies are indistinguishable as far as their stellar populations are concerned. These results favour an inside-out formation scenario and indicate that the discs in spiral galaxies of Hubble types Sbc and earlier cannot have a significant influence on the evolution of the stellar populations in the bulge component. The phenomenon of pseudobulge formation must be restricted to spirals of types later than Sbc.

show abstract

“…A key in the development of these models was the empirical calibration with globular cluster data by Maraston et al (2003). The models have subsequently been updated with new model atmosphere calculations by Korn et al (2005, see also Houdashelt et al2005) for non-solar metallicities and the higher-order Balmer line indices.…”

Section: Brief History Of Element Ratio Modellingmentioning

confidence: 99%

Element abundance ratios in stellar population modelling

Thomas

2014

Proc. IAU

View full text Add to dashboard Cite

Abstract. I review the implementation of the effects from varying chemical element abundance ratios in stellar population modelling, focusing on α-and Fe-peak elements. A brief overview of the development of such models over the past 30 years is provided, starting with early work on the identification of relevant absorption features in the spectra of early-type galaxies in the 1980s leading to the most recent developments of the past years. Recent highlights include the adoption of new flux calibrated libraries, the inclusion of a wide range of chemical elements, the calculation of error estimates on the model, and the consideration of element variation effects on full spectra. The calibration of such models with globular clusters and some key results on the element ratios measured in early-type galaxies are presented.

show abstract

Integrated spectroscopy of bulge globular clusters and fields

Cited by 112 publications

References 82 publications

Disc colours in field and cluster spiral galaxies at 0.5 ≲z≲ 0.8

Disc colours in field and cluster spiral galaxies at 0.5 ≲z≲ 0.8

Rejuvenation of spiral bulges

Element abundance ratios in stellar population modelling

Contact Info

Product

Resources

About