DOWSING, Dust Observations With SCUBA-2 In Nearby Galaxies: I. Dust in M81

@misc{uzuner2026dowsing,
  title = {{DOWSING, Dust Observations With SCUBA-2 In Nearby Galaxies: I. Dust in M81}},
  author = {M. Uzuner and M. W. L. Smith and S. Eales and A. Chung and E. J. Chung and D. L. Clements and I. De Looze and D. J. Eden and L. Fanciullo and L. C. Ho and F. Kemper and K. Pattle and M. Relaño and A. Saintonge and X. Tang and S. A. Van Der Giessen and J. Wang and T. G. Williams and C. D. Wilson},
  howpublished = {arXiv},
  year = {2026},
  month = nov,
  doi = {10.48550/arxiv.2611.07044},
  eprint = {2611.07044},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2611.07044},
}

TY  - UNPB
TI  - DOWSING, Dust Observations With SCUBA-2 In Nearby Galaxies: I. Dust in M81
AU  - M. Uzuner
AU  - M. W. L. Smith
AU  - S. Eales
AU  - A. Chung
AU  - E. J. Chung
AU  - D. L. Clements
AU  - I. De Looze
AU  - D. J. Eden
AU  - L. Fanciullo
AU  - L. C. Ho
AU  - F. Kemper
AU  - K. Pattle
AU  - M. Relaño
AU  - A. Saintonge
AU  - X. Tang
AU  - S. A. Van Der Giessen
AU  - J. Wang
AU  - T. G. Williams
AU  - C. D. Wilson
PY  - 2026
DA  - 2026/11/04
PB  - arXiv
DO  - 10.48550/arxiv.2611.07044
UR  - https://arxiv.org/abs/2611.07044
AB  - We present a resolved far-infrared/sub-millimetre study of dust in the nearby spiral galaxy M81 using Herschel PACS/SPIRE and JCMT SCUBA-2 observations from 70 to 850 μm. We model the dust emission using both single-temperature modified blackbody (SMBB) fits and point process mapping (PPMAP), comparing pixel-by-pixel SED-fitting with image cubes of dust surface density as a function of position and temperature. For fixed β= 1.9 and a dust opacity of κ_350 μm = 1.92 cm^2 g^−1, SMBB gives an integrated dust mass of (1.77 ± 0.09) × 10^7 M_⊙, while PPMAP gives (2.65 ± 0.13) ×10^7 M_⊙. The higher PPMAP mass is expected because real lines of sight contain dust over a range of temperatures, whereas SMBB assumes a single effective temperature and can underestimate the dust mass. Both methods show enhanced dust surface densities along the spiral arms and a radially declining dust temperature, with the warmest dust in the central region. Variable-β fits indicate only moderate spatial variation in β for well-constrained pixels, but the strong T-β degeneracy motivates a fixed emissivity index for the main analysis. Combining the dust maps with HI data, we find a positive radial gas-to-dust ratio gradient, with dlog_10(GDR)/dR = 0.065 dex kpc^−1. Comparison with M81's metallicity gradient implies a declining dust-to-metals ratio, potentially consistent with more efficient grain growth in the inner disc. The star formation rate is modest, ∼ 0.27 M_⊙ yr^−1, and is strongly concentrated along the spiral arms. These results suggest that the dust, gas, and star-forming structures of M81 are strongly shaped by its spiral arms, while the central region hosts the warmest dust in the disc.
ER  -