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

3.4. SNR G016.8−01.1 105
Galactic latitude
1.0
0.0
-1.0
-2.0
-3.0
-19.0 | -18.0 | -17.0 | -16.0 | -15.0 |
Galactic longitude
Figure 3.4: Neutral hydrogen column density distribution towards SNR G016.8−01.1, in-
tegrated over the velocity interval 26–34 km s −1 . Contour levels are in units of 10 19 cm −2 .
The circle marks the position of SNR G016.8−01.1, while the star represents LS 5039.
(∼ 4 × 10 20 cm −2 ), the ambient density should be ∼ 5 cm −3 . This is nearly a factor
of 3 lower than the estimated density from the expected size of the SNR if it is at
2.9 kpc. Taking into account the uncertainty in the distance, the ambient density
determined from the remnant’s size (8 < n < 23 cm −3 ) would be slightly larger than
that estimated from the H i observations. It could be that there is more material
under the form of other molecular species, or that the original SN energy release
could have been different from what we have assumed, or, finally, that the distance
to the SNR is not 2.9 kpc and it is not related to LS 5039. The case, consequently,
remains unsolved.