The INTEGRAL/IBIS Source AX J1838.0-0655: A Soft X-Ray-to-TeV γ-Ray Broadband Emitter
Abstract
We report on INTEGRAL observations of AX J1838.0-0655, one of the unidentified objects listed in the first IBIS/ISGRI survey catalog and located in the Scutum arm region. This object, detected in the 20-300 keV band at a confidence level of 15.3 σ (9 × 10-11 ergs cm-2 s-1), is the likely counterpart of the still unidentified TeV source HESS J1837-069. It has been detected in the past by various X-ray telescopes, including ASCA, implying that it is a persistent rather than a transient source; the ASCA image is compatible with the source not being resolved. The broad 1-300 keV spectrum is characterized by an absorbed [NH = (6.7 +/- 1.3) × 1022 cm-2] and hard (Γ=1.5+/-0.2) power-law continuum. Possible counterparts (radio and infrared) present within the X-ray error box are discussed, even if no clear association can be identified. The broadband spectrum together with the TeV detection suggest that AX J1838.0-0655 may be a supernova remnant or a pulsar wind nebula, which has so far eluded detection in the radio band. This is the second unidentified HESS source that shows a substantial soft gamma-ray emission.
Based on observations obtained with the ESA science mission INTEGRAL.- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 2005
- DOI:
- 10.1086/491653
- arXiv:
- arXiv:astro-ph/0507660
- Bibcode:
- 2005ApJ...630L.157M
- Keywords:
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- Gamma Rays: Observations;
- X-rays: individual (AX J1838.0-0655);
- X-rays: individual (HESS J1837-069);
- Astrophysics
- E-Print:
- 12 pages, 3 figures