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SEGUE Activity at the IAC

SEGUE Activity at the IAC. C. Allende Prieto. Summary. Software developments: new template libraries and software for the reduction pipeline. NOT (yet) for the SSPP. Research on deriving abundances of Ca, Mg, C and Si (Emma Fernández Alvar - PhD student)

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SEGUE Activity at the IAC

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  1. SEGUE Activity at the IAC C. Allende Prieto

  2. Summary • Software developments: new template libraries and software for the reduction pipeline. NOT (yet) for the SSPP. • Research on deriving abundances of Ca, Mg, C and Si (Emma Fernández Alvar - PhD student) • Building a library of stellar spectra from SDSS (pre-BOSS) stellar spectra (Victor de la Reina - summer student)

  3. New libraries • M-K type 3500-5000 K (Kurucz) • G-F type 4750-6500 K (Kurucz) • F-A-type 6250-8750 K (Kurucz) • A-type 8500-11500 K (Kurucz) • B-type 12000-26000 K (Kurucz) • O-type 27000-39000 K (Kurucz) • Hot DA white dwarfs (I. Hubeny) • Cool DA white dwarfs (D. Koester) • NLTE B-type and O-type (Tlusty) • M-L type 2000-3500 K (MARCS) • L-T type 800-2500 K (Sudarsky et al.)

  4. New libraries • M-K type 3500-5000 K (Kurucz) • G-F type 4750-6500 K (Kurucz) • F-A-type 6250-8750 K (Kurucz) • A-type 8500-11500 K (Kurucz) • B-type 12000-26000 K (Kurucz) • O-type 27000-39000 K (Kurucz) • Hot DA white dwarfs (I. Hubeny) • Cool DA white dwarfs (D. Koester) • NLTE B-type and O-type (Tlusty) • M-L type 2000-3500 K (MARCS) • L-T type 800-2500 K (Sudarsky et al.) READY!

  5. New libraries • M-K type 3500-5000 K (Kurucz) • G-F type 4750-6500 K (Kurucz) • F-A-type 6250-8750 K (Kurucz) • A-type 8500-11500 K (Kurucz) • B-type 12000-26000 K (Kurucz) • O-type 27000-39000 K (Kurucz) • Hot DA white dwarfs (I. Hubeny) • Cool DA white dwarfs (D. Koester) • NLTE B-type and O-type (Tlusty) • M-L type 2000-3500 K (MARCS) • L-T type 800-2500 K (Sudarsky et al.) Including [/Fe]

  6. Software • Gaussian LSF (fiber, ) • Quadratic interpolation of fluxes • Normalization by blocks • Full covariance matrix • Successful tests performed on MILES library

  7. Software • Gaussian LSF (fiber, ) • Quadratic interpolation of fluxes • Normalization by blocks • Successful tests performed on MILES library

  8. Continuum on This Work MILES parameters (Cenarro et al. 2009) [Fe/H] Teff logg Distributions of residuals

  9. Continuum off This Work MILES parameters (Cenarro et al. 2009) [Fe/H] Teff logg Distributions of residuals

  10. Actual SDSS/SEGUE data • NGC 2420: plate 2078 mjd 53378 • Reddening ignored! • No continuum flattening • <Fe/H> = -0.8 +/- 0.2 dex for G- and F-type stars in plate

  11. Actual SDSS data

  12. NGC 2420 • The [Fe/H] offset disappears when we flatten the continuum • The metallicities for the cluster stars show less scatter, comparable with k24 and ngs

  13. NGC 2420

  14. Abundances of Ca, Mg, C, Si • PhD student Emma Fernández Alvar • Derived sensitivity of spectrum to changes in the abundances of some 20 elements as function of Teff,logg,[Fe/H] • Currently performing simulations with Gaussian noise to quantify better previous results. Next: to incorportate Connie Rockosi’s noise model

  15. An empirical spectral library • Summer student Víctor de la Reina • Based on SSPP ‘adop’ parameters • Product is not a data base, but software • Now 3 parameters, later maybe 4 • Problem split into two: 1) choosing boxes, 2) averaging spectra • Filtering by spectra and at pixel level • 0.03 dex in logTeff, 0.5 dex in logg, 0.5 dex in [Fe/H] gives ~ 800 classes (median population ~ 100 stars/box) for 300,000+ spectra in survey=segue1-2

  16. Summary • Software developments: new template libraries and software for the reduction pipeline. NOT (yet) for the SSPP. • Research on deriving abundances of Ca, Mg, C and Si (Emma Fernández Alvar - PhD thesis) • Building a library of stellar spectra from SDSS (pre-BOSS) stellar spectra (Victor de la Reina - summer student)

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