Probing the distinct extinction law of the Pillars of Creation in M16 with JWST

TL;DR

This study uses JWST observations to analyze the extinction law in the dense Pillars of Creation, revealing a flatter curve than standard models and a divergence between mid- and near-infrared extinction behaviors, enhancing understanding of dust in dense ISM regions.

Contribution

First detailed measurement of the extinction law in the Pillars of Creation using JWST, showing deviations from typical dust models in dense interstellar regions.

Findings

Color-excess ratios indicate a flatter extinction curve than R_V=5.5 models.

Mid-infrared extinction law diverges from near-infrared power-law.

Extinction properties vary significantly in dense ISM environments.

Abstract

Investigating the extinction law in regions of high dust extinction, such as the Pillars of Creation within the M16 region, is crucial for understanding the densest parts of the interstellar medium (ISM). In this study, we utilize observations from the Near-Infrared Camera (NIRCam) and the Mid-Infrared Instrument (MIRI) onboard the James Webb Space Telescope (JWST) to analyze the color-excess ratios $E(F090W-\lambda)/E(F090W-F200W)$ across a wavelength range of $0.9-7.7\,\mu\mathrm{m}$. Our method involves performing linear regression on color-color diagrams to derive these ratios. The enhanced detection capabilities of JWST data allow us to probe the distinct extinction law to the densest regions in M16 corresponding to an extinction depth up to $A_V \sim 60$\,mag. Remarkably, the resultant color-excess ratio curve exhibits a flatter profile than predicted by typical dust extinction models with $R_V = 5.5$ for dense ISM environments. Moreover, we observe that the mid-infrared (MIR) extinction law diverges from the near-infrared (NIR) power-law, showing a tendency for the slope to flatten as the wavelength increases. These findings have significant implications for our understanding of the dust properties in dense interstellar environments.