SUMMARY OF SEQUENCE NUMBER 500000
SUMMARY OF SEQUENCE NUMBER 500000
Title: SOFT X-RAY SPECTRUM OF THE OLD NEUTRON STAR RXJ1856.5-3754
Observer: PREDEHL
Subject Category: SN, SNR, and isolated NS
Seq: 500000 ObsId: 00113
Long-term Plan bin: 8-Mar-2000
ABSTRACT
The very soft (57 eV blackbody) and very bright (3.67 ROSAT PSPC cts/sec) ROSAT source RXJ1856.5-3754 was identified recently by HST as a near-by, isolated, old, non-pulsating neutron star. The PSPC spectral blackbody fit indicates a low absorbing column density (correponding to A_V below 0.1 mag), so that this object most certainly is foreground to the R CrA dark cloud at 130 pc. With the LETG spectrum, we plan to perform photospheric spectroscopy, i.e. to check for deviations from a blackbody, e.g. due to a cyclotron emission feature in the Wien tail, or either a H, He, or Fe atmosphere. From the PSPC count rate, we can estimate that a 50 ksec AXAF LETG observation will provide sufficient S/N for distinguishing between these alternatives.
TARGET SUMMARY
| TARGET NAME |
RA | DEC |
TIME |
SI |
GRAT |
TYPE |
TC |
ROLL |
PRE |
PHASE |
MULTI |
PRI |
| RX J1856.5-3754 |
284.147083 | -37.909556 |
50.00000 |
HRC-S |
LETG |
GTO |
no |
no |
no |
no |
no |
5 |
IMAGES
(NOTE: RASS images currently only available for targets LTS scheduled on or after Apr-09-2000)
PARAMETERS
Obscat Parameters
