Abstract
High-resolution Very Large Array observations of the Arches cluster near the Galactic center show evidence of continuum emission at λ = 3.6, 6, 20, and 90 cm. The continuum emission at λ = 90 cm is particularly striking because thermal sources generally become optically thick at longer wavelengths and fall off in brightness, whereas nonthermal sources increase in brightness. It is argued that the radio emission from this unique source has compact and diffuse components produced by thermal and nonthermal processes, respectively. Compact sources within the cluster arise from stellar winds of mass-losing stars, whereas diffuse emission is likely to be due to colliding wind shocks of the cluster flow that generate relativistic particles that are due to diffuse shock acceleration. We also discuss the possibility that γ-ray emission from 3EG J1746-2851, located within 3′.3 of the Arches cluster, results from the inverse Compton scattering of the radiation field of the cluster.
| Original language | English (US) |
|---|---|
| Pages (from-to) | L103-L106 |
| Journal | Astrophysical Journal |
| Volume | 590 |
| Issue number | 2 II |
| DOIs | |
| State | Published - Jun 20 2003 |
Funding
1 Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208; [email protected], [email protected]. 2Naval Research Laboratory, Space Sciences Division, 4555 Overlook Avenue, SW, Code 7600A, Washington, DC 20375-5351; [email protected] .mil, [email protected]. 3Department of Physics, Macquarie University, NSW 2109, Australia; [email protected]. 4 Department of Physics and Astronomy, University of Iowa, 203 Van Allen Hall, Iowa City, IA 52245; [email protected]. 5The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under a cooperative agreement by Associated Universities, Inc.
Keywords
- Cosmic rays
- Galaxy: center
- ISM: abundances
- X-rays: ISM
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science