TY  - JOUR
A1  - Pohl, Martin
A1  - Macias, Oscar
A1  - Coleman, Phaedra
A1  - Gordon, Chris
T1  - Assessing the impact of hydrogen absorption on the characteristics of the Galactic center excess
T2  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We present a new reconstruction of the distribution of atomic hydrogen in the inner Galaxy that is based on explicit radiation transport modeling of line and continuum emission and a gas-flow model in the barred Galaxy that provides distance resolution for lines of sight toward the Galactic center. 

The main benefits of the new gas model are (a) the ability to reproduce the negative line signals seen with the HI4PI survey and (b) the accounting for gas that primarily manifests itself through absorption. 
We apply the new model of Galactic atomic hydrogen to an analysis of the diffuse gamma-ray emission from the inner Galaxy, for which an excess at a few GeV was reported that may be related to dark matter. 
We find with high significance an improved fit to the diffuse gamma-ray emission observed with the Fermi-LAT, if our new H i model is used to estimate the cosmic-ray induced diffuse gamma-ray emission. 
The fit still requires a nuclear bulge at high significance. Once this is included there is no evidence of a dark-matter signal, be it cuspy or cored. But an additional so-called boxy bulge is still favored by the data. 
This finding is robust under the variation of various parameters, for example, the excitation temperature of atomic hydrogen, and a number of tests for systematic issues.
Y1  - 2022
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/63627
SN  - 0004-637X
SN  - 1538-4357
VL  - 929
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -