An MeV gamma-ray all-sky simulation

GRAMS Collaboration

Research output: Contribution to journalConference articlepeer-review

Abstract

The MeV gamma-ray domain is the only unexplored window among recent multiwavelength observations in astrophysics, and is often referred to as the “MeV gap”. To bridge this gap, there are several ongoing and planned projects of MeV gamma-ray telescopes. The measurement of MeV gamma rays (both continuum and line emission) would give us new insight into many topics in astrophysics, such as studies of relativistic jets, particle acceleration, and origin of dark matter. In advance of future missions, we have been working on prediction of the MeV gamma-ray sky, which is helpful to determine what kinds of sources can be detectable with the future telescopes. In order to explore MeV gamma-ray sources, we performed a catalog cross-matching between the hard X-ray (Swift-BAT) and GeV gamma-ray (Fermi-LAT) catalogs, resulting in 145 firmly cross-matched sources. Most of the sources are brighter than 10−11 erg cm−2 s−1 in the 1–10 MeV band and thus promising targets for future observations. Combined with the Galactic diffuse and extragalactic emissions, the all-sky maps in the MeV gamma-ray band can be produced. We find that it is dominated by the Galactic diffuse emission at lower latitudes, while the extragalactic component becomes dominant at higher latitudes. This all-sky study is also used to investigate a long-standing problem in MeV gamma-ray astrophysics: the origin of the diffuse emission from the inner Galaxy, measured by COMPTEL.

Original languageEnglish
Article number664
JournalProceedings of Science
Volume444
StatePublished - Sep 27 2024
Event38th International Cosmic Ray Conference, ICRC 2023 - Nagoya, Japan
Duration: Jul 26 2023Aug 3 2023

Funding

N.T. acknowledges support from the Japan Society for the Promotion of Science KAKENHI grant No. 22K14064.

Fingerprint

Dive into the research topics of 'An MeV gamma-ray all-sky simulation'. Together they form a unique fingerprint.

Cite this