Issue |
A&A
Volume 458, Number 1, October IV 2006
|
|
---|---|---|
Page(s) | 245 - 257 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20065247 | |
Published online | 16 October 2006 |
XMM-Newton and ESO observations of the two unidentified γ-ray sources 3EG J0616-3310 and 3EG J1249-8330
1
INAF – IASF Milano, Via E. Bassini 15, 20133 Milano, Italy e-mail: nicola@iasf-milano.inaf.it
2
Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
3
Instituto de Astrofisica de Canarias, Via Lactea, 38200 La Laguna-Tenerife, Spain
4
Isaac Newton Group of Telescopes, Edificio Mayantigo, Calle Alvarez Abreu 68, 38700 Santa Cruz de la Palma, Spain
5
Centre d'Étude Spatiale des Rayonnements (CESR), CNRS–UPS, 9 Avenue du colonel Roche, 31028 Toulouse, France
6
Università di Pavia, Dipartimento di Fisica Teorica e Nucleare, via Ugo Bassi 6, 27100 Pavia, Italy
Received:
22
March
2006
Accepted:
29
June
2006
The limited angular resolution of γ-ray telescopes
prevents a direct identification of the majority of sources detected
so far. This is particularly true for the low latitude, probably
galactic, ones only 10% of which has been identified. Most
counterparts of the identified low-latitude γ-ray sources are
Isolated Neutron Stars (INS), both radio-loud and radio-quiet (Geminga-like) objects, which are characterised by an
extremely high value of the X-ray-to-optical flux ratio
. Therefore, the systematic X-ray and optical
coverage of low-latitude unidentified γ-ray sources aiming at
high
sources seems one of the most promising
ways to spot INS candidate counterparts. Since low latitude sources
are heavily affected by the interstellar absorption at both X-ray and
optical wavelengths, we have focussed on two middle-latitude,
probably galactic, GRO/EGRET sources: 3EG J0616-3310 and 3EG J1249-8330. These two sources, which could belong to a local
galactic population, have been selected owing to their relatively good
positional accuracy, spectral shape and lack of candidate
extragalactic radio counterparts. Here we report on X-ray
observations of the two γ-ray error boxes performed with XMM-Newton and on their optical follow-up carried on with the Wide Field Imager at the ESO/MPG 2.2 m telescope. Less than half of
the ~300 sources detected by the X-ray coverage have no optical
counterparts. Among those, we have selected few interesting sources
with
, which we consider promising INS
candidates.
Key words: stars: neutron / gamma-rays: observations / X-rays: general
© ESO, 2006
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