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Average extinction curves (MW, SMC, LMC)

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Average extinction curves (MW, SMC, LMC)

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  1. Wavelength dependence in the flux ratio of the double quasar SDSS J1650+4251A.M. Mosquera (Universidad de Valencia) J.A. Muñoz (Universidad de Valencia) E. Mediavilla (Instituto de Astrofísica de Canarias) R. Barrena (Instituto de Astrofísica de Canarias)

  2. Average extinction curves (MW, SMC, LMC) • Sample average extinction curves plotted along with the “average” Milky Way curve (CCM with Rv=3.1) (Gordon et al. 2003) • The 2175 Å bump is absent in the SMC bar sight lines while in other mesured extinction curves it is prominent. • Gravitationally lensed QSOs can be used to determine the extinction law in galaxies where individual stars cannot be resolved.

  3. Extinction in high redshift galaxies Zlens = 0.68 Zsource= 0.96 Zlens = 0.89 Zsource= 2.51 Zlens = 0.31 Zsource= 1.72

  4. z=0.83 Motta, Mediavilla, Muñoz et al. ApJ 2002

  5. Muñoz et al. 2004, ApJ A Survey of Extinction Curves to Redshift z=1. Project provided by NASA through grant #GO-9896 from the STSI, 2003.

  6. Observations and analysis • Object of study: double quasar SDSS J1650 + 4251, with z = 1.547 (Morgan, Snyder, Reens 2003) • Observations: NOT (2.56 m) • Wavelength interval: 3510-8130 Å • Performed PSF photometry fitting • Derive the extinction law of the lens galaxy • Discuss the 2175 Å feature I-band Image

  7. SDSS J1650+4251 images in 8 different filters Iac#28 ( = 6062Å) H ( = 6567Å) I- band ( = 8130Å) Iac#29 ( = 7015Å) Strömgren u ( = 3510Å) Strömgren v ( = 4110Å) Strömgren b ( = 4670Å) Strömgren y ( = 5470Å)

  8. I-band image (= 8130Å) SDSS J1650+4251 Modelled image without LG Residuals

  9. Strömgren-u (= 3510Å) SDSS J1650+4251 Modelled image Residuals

  10. Strömgren-y (= 5470Å) Modelled image SDSS J1650+4251 Residuals

  11. SDSS J1650 + 4251 extinction curve

  12. Conclusions • The existence of the lens galaxy has been well determined in the I-band image. • Our results are in agreement with those obtained by Morgan, Snyder, & Reens (2003) • We have estimated de extinction law of the galaxy • The absence of the 2175 Å feature is clearly confirmed with the strömgren-u data. • We have found a galaxy which extinction law behaviour is similar to the SMC

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