Статья

Detection of the 2175 A Extinction Feature at<i>z</i>= 0.83

V. MottaDepartamento de Astronomía, Facultad de Ciencias, Iguá 4225, Montevideo 11400, UruguayE. MediavillaInstituto de Astrofísica de Canarias, Vía Láctea S/N, La Laguna 38200, Tenerife, SpainJ. A. MunozInstituto de Astrofísica de Canarias, Vía Láctea S/N, La Laguna 38200, Tenerife, SpainE. FalcoHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138C. S. KochanekHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138S. ArribasConsejo Superior de Investigaciones CientíficasB. Garcia‐LorenzoIsaac Newton Group of Telescopes, 38700 S/C de La Palma, SpainA. OscozInstituto de Astrofísica de Canarias, Vía Láctea S/N, La Laguna 38200, Tenerife, SpainM. Serra‐RicartInstituto de Astrofísica de Canarias, Vía Láctea S/N, La Laguna 38200, Tenerife, Spain

2002en

ABI

Аннотация

We determine the extinction curve in the z_l=0.83 lens galaxy of the gravitational lens SBS0909+532 from the wavelength dependence of the flux ratio between the lensed quasar images (z_s=1.38) from 3400 to 9200\AA. It is the first measurement of an extinction curve at a cosmological distance of comparable quality to those obtained within the Galaxy. The extinction curve has a strong 2175\AA feature, a noteworthy fact because it has been weak or non-existent in most estimates of extinction curves outside the Galaxy. The extinction curve is fitted well by a standard $R_V=2.1\pm0.9$ Galactic extinction curve. If we assume standard Galactic extinction laws, the estimated dust redshift of $z=0.88\pm0.02$ is in good agreement with the spectroscopic redshift of the lens galaxy. The widespread assumption that SMC extinction curves are more appropriate models for cosmological dust may be incorrect.

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Идентификаторы

DOI: 10.1086/341118

Цитирования и источники

Цитирований: 2Использованных источников: 0

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