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NGC 2506 – a try for a spectroscopic study

NGC 2506 – a try for a spectroscopic study. Ekaterina Atanasova Petr Kabath Christine Oppegaard Mª Carmen Sánchez Gil Tutor: Frédéric Royer. 2nd NEON Archive Summer School 2006. Open clusters – Why are they so interesting?. The members are all at about the same distance

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NGC 2506 – a try for a spectroscopic study

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  1. NGC 2506 – a try for a spectroscopic study Ekaterina Atanasova Petr Kabath Christine Oppegaard Mª Carmen Sánchez Gil Tutor: Frédéric Royer 2nd NEON Archive Summer School 2006

  2. Open clusters – Why are they so interesting? • The members • are all at about the same distance • have approximately the same age • have about the same chemical composition • have different masses Probes for stellar evolution theories

  3. NGC 2506 Right Ascension (2000) : 08 00 01 Declination (2000) : -10 46 12 Galactic longitude : 230.564 Galactic latitude : 9.935 Distance [pc] : 3460 Reddening [mag] : 0.081 Distance modulus [mag] : 12.95 Log Age : 9.045 Metallicity : -0.37 Data from http://www.univie.ac.at/webda/ Open Cluster NGC 2506 Aladin image

  4. Spectroscopic data VLT data was obtained from the ESO Archive • 2004-01-15 Royer/Gomez • 2004-01-17 Royer/Gomez • 2004-02-14 Pallavicini et al • 2005-03-28 Grundahl et. al. • 8 scientific frames The spectra were taken using Giraffe spectrograph mounted on VLT 2 KUYEN Why Giraffe?

  5. FLAMES Instrument • Mounted on KUEYEN • Access to targets over 25' in diam. Spectrographs: • GIRAFFE R=25000 or 10000 - up to 130 targets • UVES Rmax=47000 - only 8 targets

  6. Giraffe - Spectrograph R = 7500 - 30000 Spectral region 370 – 900 nm 2K X 4K EEV CCD (15 µm pix.) Modes: • MEDUSA – 2 modes • IFU • ARGUS ARGUS: 22 times 14 1) 0.52“/microlens 2) 0.3“/microlens IFU: 20 microlenses 0.52“

  7. Possible to observe 132 objects • Resolution: each fiber equals to 1.2“ of the sky • 2 Slits - High resolution • - Low resolution • High resolution mode (HR) - 22 filters • (379 nm to 920.5 nm) • Low resolution mode (LR) - 8 filters • (385.7 nm to 881.7 nm) MEDUSA fibers (Image by ESO) MEDUSA Modes

  8. Giraffe data pipeline 3 flat fields 5 bias frames master flat field Wavelength calibration file master bias Scientific image Scientific image calibrated

  9. Calibration of a scientific frame 1 Raw bias Raw flat Master bias Master flat

  10. Calibration of a scientific frame 2 • Output = (Sci-bias)/(Master flat) • Wavelength calibration with Th-Ar Lamp Some comments • No need of dark subtraction • No flux calibration • No sky subtraction Dispersion axis Cross dispersion axis

  11. Calibrated spectra 2004-02-14

  12. Cross identification of our targets with photometric data 34 objects identified (B-V)marconi=0.032143+0.90548*(B-V)pallavicini Marconi et al., Old open clusters UBGVRI photometry of NGC 2506, MNRAS., 3 June 2006

  13. Science? 2004-02-14 Pallavicini et al. 2004-01-15 Royer/Gomez 2005-03-28 Grundahl et al. Marconi et al.

  14. Radial velocity distribution in the field =2.25206 Mean=82.8379 

  15. To be or not to be …. A member?

  16. Still a lot of work to do….but THANK YOU FOR YOUR ATTENTION:-) Jean FranÇois Petr Christine Carmen Katia

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