Sanders, Jason L;
Smith, Leigh;
González-Fernández, Carlos;
Lucas, Philip;
Minniti, Dante;
(2022)
The extinction law in the inner 3 × 3 deg² of the Milky Way and the red clump absolute magnitude in the inner bar-bulge.
Monthly Notices of the Royal Astronomical Society
, 514
(2)
pp. 2407-2424.
10.1093/mnras/stac1367.
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Abstract
The extinction law from 0.9 to 8 microns in the inner 3 × 3 deg² of the Milky Way is measured using data from VISTA Variables in the Via Lactea, GLIMPSE, and WISE. Absolute extinction ratios are found by requiring that the observed red clump density peaks at the GRAVITY collaboration distance to the Galactic centre. When combined with selective extinction ratios measured from the bulge giant colour–colour diagrams, we find an extinction law of Z : AY : AJ : AH : AKs : AW1 : A[3.6] : A[4.5] : AW2 : A[5.8] : A[8.0] = 7.19(0.30) : 5.11(0.20) : 3.23(0.11) : 1.77(0.04) : 1 : 0.54(0.02) : 0.46(0.03) : 0.34(0.03) : 0.32(0.03) : 0.24(0.04) : 0.28(0.03) low extinctions where non-linearities are unimportant. These results imply an extinction law from the Rayleigh Jeans colour excess method of A_{K}_{s} = 0.677(H − [4.5] − 0.188). We find little evidence for significant selective extinction ratio variation over the inspected region (around 5percent). Assuming the absolute extinction ratios do not vary across the inspected region gives an independent measurement of the absolute Ks magnitude of the red clump at the Galactic Centre of (−1.61 ± 0.07) mag. This is very similar to the value measured for solar neighbourhood red clump stars giving confidence in the use of red clump stars as standard candles across the Galaxy. As part of our analysis, we inspect the completeness of PSF photometry from the VVV survey using artificial star tests, finding 90percent completeness at K_{s} ≈ 16(17) in high (low) density regions and good agreement with the number counts with respect to the GALACTICNUCLEUS and DECAPS catalogues over small regions of the survey.
| Type: | Article |
|---|---|
| Title: | The extinction law in the inner 3 × 3 deg² of the Milky Way and the red clump absolute magnitude in the inner bar-bulge |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stac1367 |
| Publisher version: | http://dx.doi.org/10.1093/mnras/stac1367 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher's terms and conditions. |
| Keywords: | stars: distances, dust, extinction, Galaxy: bulge |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10150703 |
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