IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Study of the molecular clump associated with the high-energy source HESS J1858+020
Autor/es:
PARON, S. ; GIACANI, E.; RUBIO, M.; DUBNER, G.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2011 vol. 530 p. 25 - 31
ISSN:
0004-6361
Resumen:
Aims: HESS J1858+020 is a weak γ-ray source lying near the
southern border of the SNR G35.6-0.4. A molecular cloud, composed of two
clumps, shows signs of interaction with both the SNR and a nearby
extended HII region. In particular, the southernmost clump coincides
with the center of the H.E.S.S. source. We study this clump in detail to
help us identify the nature of the very-high energy emission.
Methods: We observed the aforementioned molecular clump using the
Atacama Submillimeter Telescope Experiment (ASTE) in the 12CO
J = 3-2, 13CO J = 3-2, HCO+J = 4-3, and CS J = 7-6
lines with an angular resolution of 22''. To complement these
observations, we analyzed IR and submillimeter continuum archival data.
Results: From the 12CO and 13CO J = 3-2
lines and the 1.1 mm continuum emission, we derive a density of between
103 and 4 cm-3 for the clump. We
discover a young stellar object (YSO), probably a high mass protostar,
embedded in the molecular clump. However, we do not find any evidence of
molecular outflows from this YSO that would represent a thermal jet
capable of generating the observed γ-rays. We conclude that the
most probable origin of the TeV γ-ray emission is a hadronic
interaction between the molecular gas and the cosmic rays accelerated by
the shock front of the SNR G35.6-0.4.