Continued hard X-ray activity from AXP/SGR 1E1547.0-5408 (INTEGRAL)
ATel #1922; P. R. den Hartog, L. Kuiper (SRON), W. Hermsen (SRON, UvA)
on 30 Jan 2009; 16:20 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: P.R. den Hartog (Hartog@sron.nl)
Subjects: X-ray, Gamma Ray, Neutron Star, Soft Gamma-ray Repeater, Transient
INTEGRAL continues observing the recently activated AXP/SGR
1E1547.0-5408 (GCN #8833). After the first 100ks public ToO from 2009
Jan. 24, 15:30 (UTC) to Jan. 25, 22:14 (Revolution 767, ATEL #1908)
INTEGRAL continues observing the source for 300 ks as part of an
approved ToO program. The observations started on Jan. 28 14:21 and
will cover INTEGRAL revolutions 768 up to 770, ending on Feb. 2 2009.
We have analysed 200 ks near-real-time data of revolutions 767
(public; 100ks), 768 (47 ks) and 769 (53 ks available sofar) in a
concise manner. 1E1547.0-5408 is still in a high state at hard X-rays
(>20 keV) and significantly detected in each revolution with
significances higher than 6.8 sigma. 1E1547.0-5408 is still
exhibiting bursting activity in Revs 768 and 769 (e.g. INTEGRAL Burst
Alert System IBAS). Pulsed hard X-ray emission (>20 keV) has been
detected from the INTEGRAL data (Kuiper et al. ATEL #1921).
The spectra taken from each revolution can be described by a single
power law. The 20 to 150 keV model fluxes and photon indices for each
revolution are:
| Rev | Time span | Flux+/-err (erg/cm^2/s) | Photon index+/-err |
| 767 | JAN24 15:30 -- JAN25 22:14 | (2.78 +/- 0.18)*10^-10 | 1.55 +/- 0.10 |
| 768 | JAN28 14:21 -- JAN29 03:42 | (1.86 +/- 0.27)*10^-10 | 1.44 +/- 0.21 |
| 769 | JAN29 15:05 -- JAN30 07:25 | (1.87 +/- 0.24)*10^-10 | 1.66 +/- 0.21 |
The intensity of the hard X-ray emission decreased only ~33% between
Jan. 25 and Jan. 28. Note that the spectral shape remains
stable over these observations.
These results are considered preliminary as they are derived from
near-real-time data. Further analyses are ongoing.
We thank the staff at ISOC for promptly implementing the INTEGRAL ToO
observations and ISDC scientists for making the near-real-time data
directly available.
We encourage further monitoring observations at other wavelengths
(e.g. Radio, IR and X-ray) for possible correlation studies.
