We present a new map of interstellar reddening, covering the 39% of the sky with low H I column densities (NHI< 4× 1020 cm-2 or E(B-V)≈ 45 mmag) at 16.1\prime resolution, based on all-sky observations of Galactic H I emission by the HI4PI Survey. In this low-column-density regime, we derive a characteristic value of NHI/E(B-V)=8.8 × 1021 cm2 mag-1 for gas with | vLSR| < 90 km s-1 and find no significant reddening associated with gas at higher velocities. We compare our H I-based reddening map with the Schlegel et al. (SFD) reddening map and find them consistent to within a scatter of ≃ 5 mmag. Further, the differences between our map and the SFD map are in excellent agreement with the low-resolution (4.5°) corrections to the SFD map derived by Peek and Graves based on observed reddening toward passive galaxies. We therefore argue that our H I-based map provides the most accurate interstellar reddening estimates in the low-column-density regime to date. Our reddening map is made publicly available at doi.org/10.7910/DVN/AFJNWJ.
The Astrophysical Journal
- Pub Date:
- September 2017
- ISM: general;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- Re-submitted to ApJ. The reddening map is available at http://dx.doi.org/10.7910/DVN/AFJNWJ