Mapping Dust Attenuation at Kiloparsec Scales. III. The 2175Å Bump
Abstract
We combine the Swift/UVOT+MaNGA catalog with 2MASS Ks imaging to map the 2175Å attenuation bump at kiloparsec scales in nearby galaxies. We use two complementary estimators: an ultraviolet-to-near-infrared attenuation-curve method, yielding AbumpUOIR and B for 2487 high-continuum-S/N spaxels, and the NUV-only method of \citet{2025PASA...42...22B}, yielding AbumpNUV and kbump for 7934 spaxels. The two absolute bump estimates agree well where they overlap. We compare bump strength with local stellar-population, emission-line, attenuation-curve, and geometric diagnostics after separating star-forming (SF) and non-SF regions. The strongest bumps occur at low specific Hα surface brightness, ΣHα/Σ∗, especially in non-SF regions, where this ratio traces ionized-gas emission per unit stellar mass rather than sSFR. The bump also weakens with EW(Hα) and strengthens with Dn4000 and stellar age. In contrast, metallicity, inclination, galactocentric radius, AV, and optical attenuation-curve slope are secondary predictors. The absolute strength AbumpNUV increases with ΣHα and Σ∗, while the relative strengths kbump and B do not, indicating that absolute bump amplitude partly follows dust column whereas normalized strengths better trace effective bump prominence. These results support local radiation-field processing of the 2175Å carriers.
Related
- Mapping gas accretion and stellar kinematics to sub-kiloparsec scales in NGC 4696 with JWST/NIRSpec
- NOEMA probes the [CII] and dust content in a 2175Å UV Bump Galaxy at z=7.1
- LEGGOS: A Shocking Lack of Evidence for Shocks at sub-kiloparsec Scales at 2 < z < 4
- A constant N₂H⁺ (1-0)-to-HCN (1-0) ratio on kiloparsec scales
- An empirical derivation of the average dust attenuation law at 2<z<7
BibTeX
@misc{guo2026mapping,
title = {{Mapping Dust Attenuation at Kiloparsec Scales. III. The 2175Å Bump}},
author = {Ruonan Guo and Cheng Li and Tao Jing and Shuang Zhou and Niu Li and Zhuo Cheng},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.10573},
eprint = {2607.10573},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.10573},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Mapping Dust Attenuation at Kiloparsec Scales. III. The 2175Å Bump
AU - Ruonan Guo
AU - Cheng Li
AU - Tao Jing
AU - Shuang Zhou
AU - Niu Li
AU - Zhuo Cheng
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2607.10573
UR - https://arxiv.org/abs/2607.10573
AB - We combine the Swift/UVOT+MaNGA catalog with 2MASS K_s imaging to map the 2175Å attenuation bump at kiloparsec scales in nearby galaxies. We use two complementary estimators: an ultraviolet-to-near-infrared attenuation-curve method, yielding A_bump^UOIR and B for 2487 high-continuum-S/N spaxels, and the NUV-only method of \citet{2025PASA...42...22B}, yielding A_bump^NUV and k_bump for 7934 spaxels. The two absolute bump estimates agree well where they overlap. We compare bump strength with local stellar-population, emission-line, attenuation-curve, and geometric diagnostics after separating star-forming (SF) and non-SF regions. The strongest bumps occur at low specific Hα surface brightness, Σ_Hα/Σ_∗, especially in non-SF regions, where this ratio traces ionized-gas emission per unit stellar mass rather than sSFR. The bump also weakens with EW(Hα) and strengthens with D_n4000 and stellar age. In contrast, metallicity, inclination, galactocentric radius, A_V, and optical attenuation-curve slope are secondary predictors. The absolute strength A_bump^NUV increases with Σ_Hα and Σ_∗, while the relative strengths k_bump and B do not, indicating that absolute bump amplitude partly follows dust column whereas normalized strengths better trace effective bump prominence. These results support local radiation-field processing of the 2175Å carriers.
ER -