Chandra observation of the TeV source HESS J1834-087

TL;DR

This study uses high-resolution Chandra observations to analyze the X-ray counterpart of the TeV source HESS J1834-087, revealing a point source and a compact nebula, and discusses possible interpretations including a pulsar-wind nebula.

Contribution

The paper provides the first high-resolution Chandra imaging of the field, resolving the XMM-Newton source into a point source and nebula, and reevaluates the nature of HESS J1834-087.

Findings

Resolved the XMM-Newton source into a point source and nebula.

Detected a compact nebula with a softer spectrum.

Reevaluated the source's nature, considering dust scattering and pulsar-wind nebula scenarios.

Abstract

Chandra ACIS observed the field of the extended TeV source HESS J1834-087 for 47 ks. A previous XMM-Newton EPIC observation of the same field revealed a point-like source (XMMU J183435.3-084443) and an offset region of faint extended emission. In the low-resolution, binned EPIC images the two appear to be connected. However, the high-resolution Chandra ACIS images do not support the alleged connection. Instead, in these images XMMU J183435.3-084443 is resolved into a point source, CXOU~J183434.9--084443 (L=2.5 x 10e33 ergs/s, for a distance of 4 kpc; photon index 1.1), and a compact (~20'') nebula with an isotropic morphology and a softer spectrum (L=4.2 x10e33 ergs/s, photon index 2.7). The nature of the nebula is uncertain. We discuss a dust scattering halo and a pulsar-wind nebula as possible interpretations. Based on our analysis of the X-ray data, we re-evaluate the previously suggested interpretations of HESS J1834-087 and discuss a possible connection to the Fermi LAT source 1FGL J1834.3-0842c. We also obtained an upper limit of 3 x 10e-14 ergs/s cm^2 on the unabsorbed flux of the SGR J1833--0832 (in quiescence), which happened to be in the ACIS field of view.