A systematic search for the spectra with features of crystalline silicates in the Spitzer IRS Enhanced Products

TL;DR

This study systematically searches for crystalline silicate features in a large set of Spitzer IRS spectra using a manifold ranking algorithm, identifying 868 spectra across various astronomical objects and providing valuable data for further research.

Contribution

It introduces a novel application of the manifold ranking algorithm to identify crystalline silicate features in infrared spectra from the Spitzer database.

Findings

868 spectra with crystalline silicate features identified

Different spectral features observed in young versus evolved objects

Results made publicly available for further scientific analysis

Abstract

The crystalline silicates features are mainly reflected in infrared bands. The Spitzer Infrared Spectrograph (IRS) collected numerous spectra of various objects and provided a big database to investigate crystalline silicates in a wide range of astronomical environments. We apply the manifold ranking algorithm to perform a systematic search for the spectra with crystalline silicates features in the Spitzer IRS Enhanced Products available. In total, 868 spectra of 790 sources are found to show the features of crystalline silicate. These objects are cross-matched with the SIMBAD database as well as with the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST)/DR2. The average spectrum of young stellar objects show a variety of features dominated either by forsterite or enstatite or neither, while the average spectrum of evolved objects consistently present dominant features of forsterite in AGB, OH/IR, post-AGB and planetary nebulae. They are identified optically as early-type stars, evolved stars, galaxies and so on. In addition, the strength of spectral features in typical silicate complexes is calculated. The results are available through CDS for the astronomical community to further study crystalline silicate.