The End of the Road for Far-infrared Reddening Maps? Evidence for Reddening Errors Driven by Changes in PAH Abundance
arXiv:2508.11746 · doi:10.3847/1538-4357/ae0c12
Abstract
Accurate correction for extinction by Galactic dust is essential for studying the extragalactic sky. In the low-extinction regions of the Ursa Major molecular cloud complex, we demonstrate that Galactic dust reddening maps constructed from observations of far-infrared emission are insensitive to variations in the abundance of polycyclic aromatic hydrocarbons (PAHs), and, as a result, to PAH-induced variations in reddening. Using galaxy counts to validate various reddening maps, we find evidence that maps based on far-infrared emission erroneously under-predict reddening compared to stellar reddening maps. This underestimation by far-infrared emission based reddening maps -- representing the largest discrepancy between maps of up to mag -- is correlated with the relative brightness of PAH emission. Furthermore, we demonstrate theoretically that changes in PAH abundance via accretion from the gas phase is capable of altering extinction significantly with only minor changes to far-infrared emission. We show that modeling the extinction of Ursa Major using both far-infrared and mid-infrared emission more accurately traces dust extinction variations due to changes in PAH abundance. Finally, we discuss how SPHEREx observations of the 3.3 m PAH feature are a promising way to overcome this limitation of far-infrared emission.
arXiv comment18 pages, 7 figures. Submitted to ApJ. Updated to fix typo
References in corpus (63)
- SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
- Array Programming with NumPy
- Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
- Astropy: A Community Python Package for Astronomy
- emcee: The MCMC Hammer
- The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
- The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
- Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
- HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
- The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
- Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
- Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
- Overview of the DESI Legacy Imaging Surveys
- Planck 2018 results. I. Overview and the cosmological legacy of Planck
- A 3D Dust Map Based on Gaia, Pan-STARRS 1 and 2MASS
- Planck 2013 results. XI. All-sky model of thermal dust emission
- Modelling the Galactic Interstellar Extinction Distribution in Three Dimensions
- Infrared Emission from Interstellar Dust. I. Stochastic Heating of Small Grains
- A Three-Dimensional Map of Milky-Way Dust
- Planck 2018 results. III. High Frequency Instrument data processing and frequency maps
- Dark Energy Survey Year 1 Results: Cosmological Constraints from Cluster Abundances and Weak Lensing
- Discovery of the Pure Polycyclic Aromatic Hydrocarbon Indene (-CH) with GOTHAM Observations of TMC-1
- Planck 2018 results. XI. Polarized dust foregrounds
- Polycyclic aromatic hydrocarbon processing in a hot gas
- Evolution of PAHs in photodissociation regions: Hydrogenation and charge states
- Target Selection and Validation of DESI Emission Line Galaxies
- A parsec-scale Galactic 3D dust map out to 1.25 kpc from the Sun
- Resolving nearby dust clouds
- Planck intermediate results. XXIX. All-sky dust modelling with Planck, IRAS, and WISE observations
- The Astrodust+PAH Model: A Unified Description of the Extinction, Emission, and Polarization from Dust in the Diffuse Interstellar Medium
- A new, large-scale map of interstellar reddening derived from HI emission
- Calibrating Star Formation in WISE using Total Infrared Luminosity
- Excitation of Polycyclic Aromatic Hydrocarbon (PAH) Emission: Dependence on Size Distribution, Ionization, and Starlight Spectrum and Intensity
- The Spitzer Survey of the Small Magellanic Cloud (S3MC): Insights into the Life-Cycle of Polycyclic Aromatic Hydrocarbons
- Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: NGC 628 and NGC 6946
- Dust growth in the interstellar medium: How do accretion and coagulation interplay?
- Measuring Distances and Reddenings for a Billion Stars: Towards A 3D Dust Map from Pan-STARRS 1
- Dust models compatible with Planck intensity and polarization data in translucent lines of sight
- Effects of grain size distribution on the interstellar dust mass growth
- Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample
- Modeling Thermal Dust Emission with Two Components: Application to the Planck HFI Maps
- The Dielectric Function of "Astrodust" and Predictions for Polarization in the 3.4m and 10m Features
- A Full-sky, High-resolution Atlas of Galactic 12 micron Dust Emission with WISE
- Dust-Gas Scaling Relations and OH Abundance in the Galactic ISM
- The Polycyclic Aromatic Hydrocarbon Mass Fraction on a 10 pc scale in the Magellanic Clouds
- Spatial variations in aromatic hydrocarbon emission in a dust-rich galaxy
- A Case Against Spinning PAHs as the Source of the Anomalous Microwave Emission
- A three dimensional extinction map of the Galactic Anticentre from multi-band photometry
- PHANGS-JWST First Results: Destruction of the PAH molecules in HII regions probed by JWST and MUSE
- Charting nearby dust clouds using Gaia data only
- Nested Dust Shells around the Wolf-Rayet Binary WR 140 observed with JWST
- SPHEREx: NASA's Near-Infrared Spectrophotmetric All-Sky Survey
- Extragalactic Imprints in Galactic Dust Maps
- PHANGS-JWST First Results: Variations in PAH Fraction as a Function of ISM Phase and Metallicity
- THEMIS 2.0: A self-consistent model for dust extinction, emission, and polarisation
- Three-dimensional extinction mapping using Gaussian random fields
- The effect of FIR emission from SDSS galaxies on the SFD Galactic extinction map
- Polycyclic Aromatic Hydrocarbons, the Anomalous Microwave Emission, and Their Connection to the Cold Neutral Medium
- On the origin of the North Celestial Pole Loop
- Measuring using DESI Legacy Imaging Surveys Emission-Line Galaxies and Planck CMB Lensing and the Impact of Dust on Parameter Inference
- A Deep, High-Angular Resolution 3D Dust Map of the Southern Galactic Plane
- Stellar reddening map from DESI imaging and spectroscopy
- Comparing the Photometric Calibration of DESI Imaging and Gaia Synthetic Photometry