Universitat de - Departament d'Astronomia i Meteorologia ...

76 Chapter 2. Multiwavelength approach to LS 5039
RX J1826.2−1450 / LS 5039, within the 3EG J1824−1514 contours, and well inside
the 95% confidence contour. Moreover, this is the only X-ray source, bright or faint,
that also displays radio emission (addition of NVSS sources below 20 mJy does not
change this discussion). Such a good position agreement between an EGRET source
and a radio jet X-ray binary strongly suggests that both objects may be the same.
Thus, this microquasar system is likely associated with an EGRET source.
As can be seen in Fig. 2.19, the γ-ray emission observed from 3EG J1824−1514
reveals a rather persistent flux of > 100 MeV photons for the last decade. This
persistent behavior is also seen at radio wavelengths in LS 5039, thus giving support
to the proposed association.
s −1
]
photon cm −2
γ−ray flux [10 −8
80
60
40
20
EGRET (>100 MeV)
VLA (1.45 GHz)
GBI (2.25 GHz)
0
1988 1990 1992 1994 1996 1998 2000
0
2002
Year
Figure 2.19: Radio and γ-ray lightcurves of LS 5039 and 3EG J1824−1514. The radio
flux densities are the VLA ones at 20 cm wavelength (1.45 GHz) quoted in Table 2.1
and the GBI ones presented in Sect. 2.4.3. The error bars for the GBI data (±4 mJy)
are not shown for clarity, whereas those of the VLA are usually smaller than the symbol
size. The γ-ray fluxes correspond to the four viewing periods of EGRET.
80
60
40
20
Radio flux density [mJy]