2020 Fiscal Year Research-status Report
Closing in on the ultimate Dark Matter limits forecast by the Fermi Gamma-Ray Space Telescope
| Project/Area Number |
20K14463
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2020-04-01 – 2022-03-31
|
| Keywords | dark matter / Galactic Center / gamma rays / pulsars / cosmic rays |
|---|
| Outline of Annual Research Achievements |
The main result of this investigation has been published in Phys. Rev. D 103 (2021) 2, 023011, with title: “Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center”. In this paper, we noted that the extended excess toward the Galactic Center (GC) in gamma rays inferred from Fermi-LAT observations has been interpreted as being due to dark matter (DM) annihilation. In summary, we performed new likelihood analyses of the GC and showed that, when including templates for the stellar galactic and nuclear bulges, the GC shows no significant detection of a DM annihilation template, even after generous variations in the Galactic diffuse emission models and a wide range of DM halo profiles. We included Galactic diffuse emission models with combinations of three-dimensional inverse Compton maps, variations of interstellar gas maps, and a central source of electrons. For the DM profile, we included both spherical and ellipsoidal DM morphologies and a range of radial profiles from steep cusps to kiloparsec-sized cores, motivated in part by hydrodynamical simulations. Our derived upper limits on the dark matter annihilation flux place strong constraints on DM properties. In the case of the pure b-quark annihilation channel, our limits on the annihilation cross section are more stringent than those from the Milky Way dwarfs up to DM masses of approximately TeV and rule out the thermal relic cross section up to approximately 300 GeV.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The project is progressing very well. The core objective has been reached, that is obtaining strong robust constrains on self-annihilating dark matter particles. The remaining specific objectives will be possible to complete on time, by the end of planned funding for this project.
|
| Strategy for Future Research Activity |
For the remaining part of the project, I plan to continue investigating how to distinguish the dark matter hypothesis from the millisecond pulsar explanation by using multiwavelength data. For example, I have already submitted for publication the following preprint https://arxiv.org/abs/2102.05648, in which we investigate the capabilities of the forthcoming Cherenkov Telescope Array to distinguish the two hypothesis for the Galactic center gamma-ray excess.
In addition, I am making predictions of the expected radio signatures for both dark matter and pulsars, in order to obtain the constraining capabilities of radio data. The radio predictions are being performed by solving the cosmic ray transport equation numerically using publicly available code.
|
Research Products
(6 results)
