J/A+A/584/A41 SNR IKT 16 X-ray image (Maitra+, 2015)
IKT 16: the first X-ray confirmed composite SNR in the SMC.
Maitra C., Ballet J., Filipovic M.D., Haberl F., Tiengo A., Grieve K.,
Roper Q.
<Astron. Astrophys. 584, A41 (2015)>
=2015A&A...584A..41M 2015A&A...584A..41M (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Supernova remnants ; X-ray sources
Keywords: Magellanic Clouds - ISM: supernova remnants
Abstract:
IKT 16 is an X-ray and radio-faint supernova remnant (SNR) in the
Small Magellanic Cloud (SMC). A detailed X-ray study of this SNR with
XMM-Newton confirmed the presence of a hard X-ray source near its
centre, indicating the detection of the first composite SNR in the
SMC. With a dedicated Chandra observation we aim to resolve the point
source and confirm its nature. We also acquire new ATCA observations
of the source at 2.1GHz with improved flux density estimates and
resolution.
We perform detailed spatial and spectral analysis of the source. With
the highest resolution X-ray and radio image of the centre of the SNR
available today, we resolve the source and confirm its pulsar wind
nebula (PWN) nature. Further, we constrain the geometrical parameters
of the PWN and perform spectral analysis for the point source and the
PWN separately. We also test for the radial variations of the PWN
spectrum and its possible east west asymmetry.
The X-ray source at the centre of IKT 16 can be resolved into a
symmetrical elongated feature centring a point source, the putative
pulsar. Spatial modelling indicates an extent of 5.2" of the feature
with its axis inclined at 82° east from north, aligned with a
larger radio feature consisting of two lobes almost symmetrical about
the X-ray source. The picture is consistent with a PWN which has not
yet collided with the reverse shock. The point source is about three
times brighter than the PWN and has a hard spectrum of spectral index
1.1 compared to a value 2.2 for the PWN. This points to the presence
of a pulsar dominated by non-thermal emission. The expected dE/dt
is ∼1037erg/s and spin period <100ms. However, the presence of a
compact nebula unresolved by Chandra at the distance of the SMC cannot
completely be ruled out.
Description:
The Chandra observation (ObsID 13773) was carried out with the ACIS-S
as the primary instrument in the timed exposure mode. The observation
was performed on 09-02-2013 with the central source of IKT 16
positioned at the aimpoint of the S3 CCD with an exposure of 38.5ks.
It is worthwhile to mention here that there was a previous Chandra
observation (obsID 2948, 9ks) where the source was detected (Evans et
al., 2010ApJS..189...37E 2010ApJS..189...37E). But the short duration of this observation
and its large off axis angle prevented further investigation of the
source from this data.
Objects:
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RA (2000) DE Designation(s)
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00 58 18.40 -72 17 22.7 IKT 16 = SNR B0056-72.5
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 105 3 Informations on fits images
fits/* . 3 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right ascension of image center (J2000)
10- 18 F9.5 deg DEdeg Declination of image center (J2000)
20- 22 I3 --- Nx [50/780] Number of pixels along X-axis
24- 26 I3 --- Ny [40/760] Number of pixels along Y-axis
28- 46 A19 --- Obs.Date Observation date (YYYY-MM-DDThh:mm:ss)
48- 51 I4 Kibyte size [22/4717] Size of the fits file
53- 70 A18 --- FileName Name of the fits file in subdirectory fits
72-105 A34 --- Title Title of the file
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Acknowledgements:
Chandreyee Maitra, Chandreyee.Maitra(at)cea.fr
(End) Patricia Vannier [CDS] 17-Nov-2015