  While iron emission lines are well studied in black hole systems, both in
X-ray binaries and Active Galactic Nuclei, there has been less of a focus on
these lines in neutron star low-mass X-ray binaries (LMXBs). However, recent
observations with Suzaku and XMM-Newton have revealed broad asymmetric iron
line profiles in 4 neutron star LMXBs, confirming an inner disk origin for
these lines in neutron star systems. Here, we present a search for iron lines
in 6 neutron star LMXBs. For each object we have simultaneous Chandra and RXTE
observations at 2 separate epochs, allowing for both a high resolution
spectrum, as well as broadband spectral coverage. Out of the six objects in the
survey, we only find significant iron lines in two of the objects, GX 17+2 and
GX 349+2. However, we cannot rule out that there are weak, broad lines present
in the other sources. The equivalent width of the line in GX 17+2 is consistent
between the 2 epochs, while in GX 349+2 the line equivalent width increases by
a factor of ~3 between epochs as the source flux decreases by a factor of 1.3.
This suggests that the disk is highly ionized, and the line is dominated by
recombination emission. We find that there appears to be no specific locations
in the long-term hardness-intensity diagrams where iron emission lines are
formed, though more sources and further observations are required.

Astrophysics