Contributed Talk

Detections of Diffuse Interstellar Bands in the SDSS Low-resolution Spectra

^1,2Hai-Bo Yuan, ^1,3Xiao-Wei Liu (¹Kavli Institute for Astronomy and Astrophysics, Peking University, ²LAMOST Fellow, ³Department of Astronomy, Peking University)

Diffuse interstellar bands (DIBs) have been discovered for almost a century, but their nature is still a challenging problem in astronomical spectroscopy. In recent years, high-resolution spectroscopic observations are mostly carried out to identify and study DIBs. In this contribution, we present our work on detections of DIBs in the SDSS low-resolution spectra. Using template subtraction method, we have successfully identified the DIBs 5780, 6284 in the SDSS spectra of a sample of 2164 stars and measured their line widths, strengths and velocities, which is so far the largest sample of stars with DIBs detected and measured. The sample is distributed over a large sky area and involves a wide range of stellar parameters in effective temperature, surface gravity and metallicity, confirming that carriers of DIBs are ubiquitous in the interstellar medium. Using the sample, we investigate relations between strengths of DIBs and line of sight extinction and find consistent results with previous studies. DIB features are also detected in the commissioning spectra of LAMOST, which have similar resolving power of SDSS. Detections of DIBs in hundreds of thousands of stars are expected from the on-going and upcoming large scale spectroscopic surveys such as SDSS and LAMOST, especially from the LAMOST Digital Sky Survey of the Galactic Anti-center (DSS-GAC) project. With such a huge database, we discuss possible opportunities in DIB studies as well as various implications of DIBs as tracers of interstellar medium and indicators of extinction.

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