Constraining Dust Properties Along the Minor Axis of Andromeda

@misc{jiao2026constraining,
  title = {{Constraining Dust Properties Along the Minor Axis of Andromeda}},
  author = {Sihan Jiao and Linjing Feng and Henrik Beuther and Hauyu Baobab Liu and Yuxin Lin and Jingwen Wu and Chao-Wei Tsai and Di Li and Kiyoaki Doi and Jakob den Brok and Fengwei Xu and Simón D. Reyes-Reyes and Carsten Kramer and Ryan P. Keenan and Xiangyu Zhang and Fanyi Meng and Zongnan Li and Fangyuan Deng and Yuxiang Liu},
  howpublished = {arXiv},
  year = {2026},
  month = nov,
  doi = {10.48550/arxiv.2611.04319},
  eprint = {2611.04319},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2611.04319},
}

TY  - UNPB
TI  - Constraining Dust Properties Along the Minor Axis of Andromeda
AU  - Sihan Jiao
AU  - Linjing Feng
AU  - Henrik Beuther
AU  - Hauyu Baobab Liu
AU  - Yuxin Lin
AU  - Jingwen Wu
AU  - Chao-Wei Tsai
AU  - Di Li
AU  - Kiyoaki Doi
AU  - Jakob den Brok
AU  - Fengwei Xu
AU  - Simón D. Reyes-Reyes
AU  - Carsten Kramer
AU  - Ryan P. Keenan
AU  - Xiangyu Zhang
AU  - Fanyi Meng
AU  - Zongnan Li
AU  - Fangyuan Deng
AU  - Yuxiang Liu
PY  - 2026
DA  - 2026/11/03
PB  - arXiv
DO  - 10.48550/arxiv.2611.04319
UR  - https://arxiv.org/abs/2611.04319
AB  - Previous studies of dust emission in M31 based primarily on Herschel data have reported inconsistent radial trends in the dust emissivity index (β), partly due to limited wavelength coverage and the intrinsic T_dust-β degeneracy. We aim to improve the constraints of β determinations and obtain the spatial surface density and temperature distributions at GMC scales in M31 by extending the spectral coverage into the millimeter regime and by quantifying the impact of wavelength coverage on the T_dust-β degeneracy. We present new IRAM 30m NIKA2 1.15 mm observations along the minor axis of M31 at an angular resolution of 11 arcsec, corresponding to ∼ 40 pc at the distance of M31. These data are used with Herschel and JCMT SCUBA-2 maps to perform pixel-by-pixel single-component modified blackbody fitting. Including the 850 μm and 1.15 mm data helps reduce the T_dust-β degeneracy and yields an average emissivity index of β≈ 1.8, systematically lower than values derived from far-infrared-only analyses. Radial analysis shows higher β values in the 5 kpc ring compared to the 10 kpc ring. The elevated β values in the inner 5 kpc may be linked to changes in dust composition, potentially associated with enhanced starlight heating in this region. Millimeter wavelength coverage is important for improving β constraints in M31. The lower β values inferred from the 250--1150 μm SED fitting suggest possible variations in dust emissivity and highlight the importance of sampling the long-wavelength SED slope in nearby galaxies.
ER  -