NICER observation list: Target ID 366701
- Proposal Number = 3667
- Target ID = 366701
- Target Name = 4U_1538-52
- Proposal Title = UNRAVELLING THE ENIGMATIC SUPER-ORBITAL MODULATION OBSERVED IN 4U 1538-52
- PI = NAZMA ISLAM
- Proposal Category = X-RAY BINARIES
- Cycle number = 3
- Observation Type = NOR
Abstract
The puzzling variety of super-orbital modulations seen in the long term light-curves of Supergiant High Mass X-ray binaries (sgHMXBs), opens up new questions on the stellar wind interaction with a highly magnetised neutron star. We propose a joint 40 ks NuSTAR + 10 ks NICER observation of the persistent sgHMXB 4U 1538-52 at its super-orbital maximum and minimum to conclusively understand the mechanisms driving these flux modulations. The results of energy resolved pulsation studies, pulse phase resolved spectroscopic study of photon indices, absorption column density and cyclotron lines will be used to differentiate or constrain the various models explaining these super-orbital modulations.
| Obsid |
RA |
DEC |
l |
b |
Start |
End |
Exposure |
Number of
Modules |
Number of
Processing |
Status of
Processing |
Date of
Processing |
Public
date |
| 3667010101 |
235.603 |
-52.388 |
327.421 |
2.160 |
59216.0467 |
59216.2044 |
0.0 |
47 |
3 |
VALIDATED |
59220.7 |
59590 |
| 3667010201 |
235.602 |
-52.386 |
327.422 |
2.162 |
59221.9155 |
59221.9470 |
0.0 |
47 |
4 |
VALIDATED |
59244.0 |
59595 |
| 3667010202 |
235.601 |
-52.386 |
327.421 |
2.162 |
59221.9813 |
59222.0759 |
0.0 |
47 |
6 |
VALIDATED |
59244.0 |
59596 |
| 3667010301 |
235.597 |
-52.386 |
327.419 |
2.164 |
59261.3666 |
59261.8324 |
7272.0 |
52 |
2 |
VALIDATED |
59270.9 |
59635 |
| 3667010302 |
235.594 |
-52.384 |
327.419 |
2.167 |
59267.0324 |
59267.1123 |
41.0 |
52 |
1 |
VALIDATED |
59271.1 |
59641 |
| 3667010401 |
235.595 |
-52.385 |
327.419 |
2.165 |
59267.1630 |
59267.5641 |
1625.0 |
52 |
1 |
VALIDATED |
59271.1 |
59641 |