Untangling dust emission and cosmic infrared background anisotropies with the scattering transform statistics
Abstract
Context. A template-fit approach is often used to separate the Galactic dust emission and the cosmic infrared background (CIB) anisotropies in low H I column density regions using the observational fact that the 21 cm H I line emission from neutral atomic hydrogen and dust are tightly correlated. However, in some regions with molecular hydrogen, diffuse ionised gas, and dark gas, the same approach fails to trace the excess Galactic dust emission. Aims. We developed and tested a statistical component-separation method to extract the dust signal from the contaminated Planck 353 GHz observations using the scattering covariance (SC) statistics, which is a subclass of scattering transform statistics. Methods. We first obtained a set CIB maps over 25 square patches, each with a sky area of 222 deg 2 , using the linear correlation of dust and Galactic H I column density map valid in low H I column density regions using the template-fit approach. We then constructed from these 25 maps a generative model of CIB using SC statistics. We finally relied on this generative model to perform a componentseparation of dust and CIB in the Planck data for different sky regions. These separations were achieved by sampling an ensemble of dust maps through pixel-based optimisation, which, when added to the CIB contamination model, verified all the statistics and cross statistics constraints that were estimated directly from the data. Results. We validated our algorithm and separated the dust emission from the contamination in the Planck 353 GHz observations. We show the results of the recovered dust map for a test sky region where there is a significant difference between the Planck dust map and CSFD map. We found that the Planck dust map has more structure than the CSFD map. We compared the power spectrum of the recovered dust map and H I map and found a difference in slope (∆α ≈ 0.4) by fitting a power-law model to the two spectra. To explain ∆α, we decomposed the recovered dust map into two gas phases: dust associated with neutral atomic hydrogen, and dust associated with molecular hydrogen. We provide a clear pathway to mapping the Galactic interstellar reddening over intermediate and high Galactic latitudes.
Related
- Non-linear halo bias for accurate modelling of cosmic infrared background anisotropies
- Approximating the statistics of a gravitational wave background
- Higher-order statistics of the stochastic gravitational wave background from supermassive black hole binaries
- HierArchical Wavelet Coefficients on the Sphere (HAWCS): the Scattering Transform on Spherical Maps
- Fast Radio Burst Scattering Statistics through the Circumgalactic Medium Are Sensitive to Morphology and Intermittency
BibTeX
@article{sinha2026untangling,
title = {{Untangling dust emission and cosmic infrared background anisotropies with the scattering transform statistics}},
author = {Srijita Sinha and Tuhin Ghosh and Erwan Allys and François Boulanger and Jean-Marc Delouis},
journal = {Astronomy \& Astrophysics - A\&A},
year = {2026},
month = jul,
doi = {10.1051/0004-6361/202659670},
eprint = {2603.06110},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05762713v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Untangling dust emission and cosmic infrared background anisotropies with the scattering transform statistics
AU - Srijita Sinha
AU - Tuhin Ghosh
AU - Erwan Allys
AU - François Boulanger
AU - Jean-Marc Delouis
PY - 2026
DA - 2026/07/23
JO - Astronomy & Astrophysics - A&A
DO - 10.1051/0004-6361/202659670
UR - https://hal.science/hal-05762713v1
AB - Context. A template-fit approach is often used to separate the Galactic dust emission and the cosmic infrared background (CIB) anisotropies in low H I column density regions using the observational fact that the 21 cm H I line emission from neutral atomic hydrogen and dust are tightly correlated. However, in some regions with molecular hydrogen, diffuse ionised gas, and dark gas, the same approach fails to trace the excess Galactic dust emission. Aims. We developed and tested a statistical component-separation method to extract the dust signal from the contaminated Planck 353 GHz observations using the scattering covariance (SC) statistics, which is a subclass of scattering transform statistics. Methods. We first obtained a set CIB maps over 25 square patches, each with a sky area of 222 deg 2 , using the linear correlation of dust and Galactic H I column density map valid in low H I column density regions using the template-fit approach. We then constructed from these 25 maps a generative model of CIB using SC statistics. We finally relied on this generative model to perform a componentseparation of dust and CIB in the Planck data for different sky regions. These separations were achieved by sampling an ensemble of dust maps through pixel-based optimisation, which, when added to the CIB contamination model, verified all the statistics and cross statistics constraints that were estimated directly from the data. Results. We validated our algorithm and separated the dust emission from the contamination in the Planck 353 GHz observations. We show the results of the recovered dust map for a test sky region where there is a significant difference between the Planck dust map and CSFD map. We found that the Planck dust map has more structure than the CSFD map. We compared the power spectrum of the recovered dust map and H I map and found a difference in slope (∆α ≈ 0.4) by fitting a power-law model to the two spectra. To explain ∆α, we decomposed the recovered dust map into two gas phases: dust associated with neutral atomic hydrogen, and dust associated with molecular hydrogen. We provide a clear pathway to mapping the Galactic interstellar reddening over intermediate and high Galactic latitudes.
SN - 0004-6361
SN - 1432-0746
ER -