FLAMES: a multi-object fiber facility for the VLT

Pasquini, L.; Ávila, G.; Allaert, E.; Ballester, P.; Biereichel, P.; Buzzoni, B.; Cavadore, Cyril; Dekker, H.; Délabre, Bernard; Ferraro, F. R.; Hill, V.; Kaufer, A.; Kotzlowski, Heinz; Lizon, J. L.; Longinotti, Antonio; Moureau, S.; Palsa, Ralf; Zaggia, S.

doi:10.1117/12.395491

Cited by 70 publications

(38 citation statements)

References 1 publication

(1 reference statement)

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“…Therefore either such very metal-poor component has a very low space density in field 1, perhaps is even absent, or our selection criterion has totally missed this population. This issue needs to be elucidated by the observation of a larger number of stars in the field which we plan to perform with the FLAMES facility on the VLT (Pasquini et al 2000.…”

Section: Discussionmentioning

confidence: 99%

The Sgr dSph hosts a metal-rich population

Bonifacio

Sbordone

Marconi

et al. 2004

A&A

114

163

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Abstract.We report on abundances of O, Mg, Si, Ca and Fe for 10 giants in the Sgr dwarf spheroidal derived from high resolution spectra obtained with UVES at the 8.2 m Kueyen-VLT telescope. The iron abundance spans the range −0.8 < ∼ [Fe/H] < ∼ 0.0 and the dominant population is relatively metal-rich with [Fe/H] ∼ −0.25. The α/Fe ratios are slightly subsolar, even at the lowest observed metallicities suggesting a slow or bursting star formation rate. From our sample of 12 giants (including the two observed by Bonifacio et al. 2000) we conclude that a substantial metal rich population exists in Sgr, which dominates the sample. The spectroscopic metallicities allow one to break the age-metallicity degeneracy in the interpretation of the colour-magnitude diagram (CMD). Comparison of isochrones of appropriate metallicity with the observed CMD suggests an age of 1 Gyr or younger, for the dominant Sgr population sampled by us. We argue that the observations support a star formation that is triggered by the passage of Sgr through the Galactic disc, both in Sgr and in the disc. This scenario has also the virtue of explaining the mysterious "bulge C stars" as disc stars formed in this event. The interaction of Sgr with the Milky Way is likely to have played a major role in its evolution.

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Section: Discussionmentioning

confidence: 99%

The Sgr dSph hosts a metal-rich population

Bonifacio

Sbordone

Marconi

et al. 2004

A&A

114

163

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“…Finally, an optical spectrum covering the wavelength range 3850-4755 Å and 6380-6610 Å with S /N ≈ 250 (at about 4725 Å) and R varying between ∼20 000−30 000 is at our disposal, taken on 26/02/2000 with FLAMES/GIRAFFE on the ESO VLT (Pasquini et al 2000). See Evans et al (2005) and Maeder et al (2014) for details of the observations, data reduction, and post-processing of the spectra.…”

Section: Observationsmentioning

confidence: 99%

B fields in OB stars (BOB): Detection of a magnetic field in the He-strong star CPD −57° 3509

Przybilla

Fossati

Hubrig

et al. 2016

A&A

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Aims. We report the detection of a magnetic field in the helium-strong star CPD −57 • 3509 (B2 IV), a member of the Galactic open cluster NGC 3293, and characterise the star's atmospheric and fundamental parameters. Methods. Spectropolarimetric observations with FORS2 and HARPSpol are analysed using two independent approaches to quantify the magnetic field strength. A high-S/N FLAMES/GIRAFFE spectrum is analysed using a hybrid non-LTE model atmosphere technique. Comparison with stellar evolution models constrains the fundamental parameters of the star. Results. We obtain a firm detection of a surface averaged longitudinal magnetic field with a maximum amplitude of about 1 kG. Assuming a dipolar configuration of the magnetic field, this implies a dipolar field strength larger than 3.3 kG. Moreover, the large amplitude and fast variation (within about 1 day) of the longitudinal magnetic field implies that CPD −57 • 3509 is spinning very fast despite its apparently slow projected rotational velocity. The star should be able to support a centrifugal magnetosphere, yet the spectrum shows no sign of magnetically confined material; in particular, emission in Hα is not observed. Apparently, the wind is either not strong enough for enough material to accumulate in the magnetosphere to become observable or, alternatively, some leakage process leads to loss of material from the magnetosphere. The quantitative spectroscopic analysis of the star yields an effective temperature and a logarithmic surface gravity of 23 750 ± 250 K and 4.05 ± 0.10, respectively, and a surface helium fraction of 0.28 ± 0.02 by number. The surface abundances of C, N, O, Ne, S, and Ar are compatible with the cosmic abundance standard, whereas Mg, Al, Si, and Fe are depleted by about a factor of 2. This abundance pattern can be understood as the consequence of a fractionated stellar wind. CPD −57 • 3509 is one of the most evolved He-strong stars known with an independent age constraint due to its cluster membership.

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“…The observations have been performed with the multiplex facility FLAMES@ESO-VLT (Pasquini et al 2000) in the UVES+GIRAFFE combined mode (Prop. ID: 093.D-0618, PI: Dalessandro).…”

Section: Observationsmentioning

confidence: 99%

NGC 6362: The Least Massive Globular Cluster With Chemically Distinct Multiple Populations*

Mucciarelli

Dalessandro

Massari

et al. 2016

ApJ

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We present the first measure of Fe and Na abundances in NGC 6362, a low-mass globular cluster (GC) where firstand second-generation stars are fully spatially mixed. A total of 160 member stars (along the red giant branch (RGB) and the red horizontal branch (RHB)) were observed with the multi-object spectrograph FLAMES at the Very Large Telescope. We find that the cluster has an iron abundance of [Fe/H] = −1.09 ± 0.01 dex, without evidence of intrinsic dispersion. On the other hand, the [Na/Fe] distribution turns out to be intrinsically broad and bimodal. The Na-poor and Na-rich stars populate, respectively, the bluest and the reddest RGBs detected in the color-magnitude diagrams including the U filter. The RGB is composed of a mixture of first-and secondgeneration stars in a similar proportion, while almost all the RHB stars belong to the first cluster generation. To date, NGC 6362 is the least massive GC where both the photometric and spectroscopic signatures of multiple populations have been detected.

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FLAMES: a multi-object fiber facility for the VLT

Cited by 70 publications

References 1 publication

The Sgr dSph hosts a metal-rich population

The Sgr dSph hosts a metal-rich population

B fields in OB stars (BOB): Detection of a magnetic field in the He-strong star CPD −57° 3509

NGC 6362: The Least Massive Globular Cluster With Chemically Distinct Multiple Populations*

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