INVESTIGADORES
COMBI Jorge Ariel
artículos
Título:
A variability analysis of low-latitude unidentified gamma-ray sources
Autor/es:
D.F. TORRES; ROMERO, G. E.; COMBI, J. A.; BENAGLIA, PAULA; ANDERNACH, H; B. PUNSLY
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2001 vol. 370 p. 468 - 478
ISSN:
0004-6361
Resumen:
We present a study of 40 low-latitude unidentified 3EG gamma-ray sources
which were found to be not positionally coincident with any known class
of potential gamma-ray emitters in the Galaxy (Romero et al. 1999). We
have performed a variability analysis which reveals that many of these
40 sources are variable. These sources have, in addition, a steep mean
value of the gamma-ray spectral index, <Gamma > = 2.41 +/- 0.2,
which, combined with the high level of variability, seems to rule out a
pulsar origin. The positional coincidences with uncatalogued candidates
to supernova remnants were also studied. Only 7 sources in the sample
are spatially coincident with these candidates, a result that is shown
to be consistent with the expected level of pure chance association. A
complementary search for weak radio counterparts was also conducted and
the results are presented as an extensive table containing all
significant point-like radio sources within the 40 EGRET fields. We
argue that in order to produce the high variability, steep gamma-ray
spectra, and absence of strong radio counterparts observed in some of
the gamma-ray sources of our sample, a new class of objects should be
postulated, and we analyze a viable candidate. Tables 5--8 are only
available in electronic form at the CDS via anonymous ftp to
cdsarc.u-strasbg.fr (130.79.128.5}) or via
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/370/468}