J/A+A/680/A80 3D dynamics of Tycho's SNR (Godinaud+, 2023)
A fresh perspective on the 3D dynamics of Tycho's supernova remnant:
Ejecta asymmetries in X-rays.
Godinaud L., Acero F., Decourchelle A., Ballet J.
<Astron. Astrophys. 680, A80 (2023)>
=2023A&A...680A..80G 2023A&A...680A..80G (SIMBAD/NED BibCode)
ADC_Keywords: Supernova remnants ; X-ray sources ; Proper motions
Keywords: ISM: supernova remnants - ISM: individual objects: Tycho's SNR -
methods: data analysis
Abstract:
Even 450 years after the explosion of the Type Ia SN1572, the dynamics
of the Tycho supernova remnant can give us keys to understand the
explosion mechanism and the interaction of the remnant with the
interstellar medium.
To probe the asymmetries and the evolution of the SNR, we track the
ejecta dynamics using new methods applied to the deep X-ray
observations available in the Chandra space telescope archive.
For the line of sight velocity measurement Vz, we use the Doppler
effect focused on the bright Si line in the 1.6-2.1keV band. Using
the component separation tool General Morphological Component Analysis
(GMCA), we successfully disentangle the red and blueshifted Si ejecta
emission. This allows us to reconstruct a map of the peak energy of
the Si line with a total coverage of the SNR at a 2'' resolution and a
proxy of the velocity in the line of sight. For the proper motions in
the plane of the sky Vxy, we develop a new method, named Poisson
Optical Flow, to measure the displacement of 2D features between the
observations of 2003 and 2009. The result is a field of 1700 velocity
vectors covering the entire SNR.
These exhaustive 3D velocity measurements reveal the complex and
patchy dynamics of the SNR. At the large-scale, an asymmetry with the
North being dominantly blueshifted and the South redshifted is
observed. The proper motion vector field Vxy highlights different
dynamics between the East and the West parts of the SNR. The eastern
velocity field is more disturbed by external inhomogeneities and the
South-East ejecta knot. In particular, a slow-down is observed in the
North-East which could be due to the interaction with higher densities
as seen in other wavelengths. The vector field is also used to
backtrace the center of the explosion which is then compared with
potential stellar progenitors distances from the latest Gaia DR3,
leaving only stars B and E as possible candidates, at respective
distances of 2.53-0.20+0.23kpc and 3.52-1.0+2.0kpc, which are
consistent with the expected distance range of the SNR at 2.5-4kpc.
Description:
fig6.dat (Fig 6 in the article):
Velocity vector field in the plane of sky of the Tycho supernova
remnant.
We use the archival data of the Chandra space telescope in X-ray, in
particular the deep observations of 2003 and 2009 (see article for the
list of ObsID).
With the innovative method Poisson Optical Flow (POF), we obtain 1722
vectors with a full coverage of the remnant. The positions of the
origin of the arrow and velocities (in km/s) according the RA and Dec
axis are presented in this file.
The asymmetric error at 90% confidence level along each axis is
provided.
A distance to the Tycho SNR of 3.5kpc is assumed to derive the
velocity.
We note that the cross in the middle of our vector field is due to the
CCD gaps in the camera of Chandra.
cube of images (Fig 1, bottom panel, in the article) :
Maps of the three components obtained with the General Morphological
Component Analysis (GMCA) tool.
We use all the observations of 2009 of the Chandra space telescope
limited on the silicon energy band.
The binning of these maps is four times the native binning of Chandra.
Objects:
--------------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------------
00 25 21.52 +64 08 26.8 Tycho SNR = HR 92
--------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
fig6.dat 56 1722 *Proper motion vector field between 2003 and 2009
obtained with the tool POF
list.dat 177 1 Informations on fits image datacube
fits/* . 1 fits image datacube
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Note on fig6.dat:
Table 1: Chandra observations used in this study
-----------------------------------------------------------------
ObsId Date Exposure time (ks)
-----------------------------------------------------------------
3837 2003/04/29 145.6
10093 2009/04/13 118.4
10094 2009/04/18 90.0
10095 2009/04/23 173.4
10096 2009/04/27 105.07
10097 2009/04/11 107.4
10902 2009/04/15 39.5
10903 2009/04/17 23.9
10904 2009/04/13 34.7
10906 2009/05/03 41.1
-----------------------------------------------------------------
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See also:
J/MNRAS/439/354 : Sources around Tycho's Supernova 1572 (Bedin+, 2014)
Byte-by-byte Description of file: fig6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.4 deg RAdeg Right ascension (J2000)
8- 14 F7.4 deg DEdeg Declination (J2000)
16- 22 F7.1 km/s VRA Proper motion vector field component along RA
24- 30 F7.1 km/s VDE Proper motion vector field component along DE
32- 36 F5.1 km/s E_VRA Error on VRA (upper value)
39- 43 F5.1 km/s e_VRA Error on VRA (lower value)
45- 49 F5.1 km/s E_VDE Error on VDE (upper value)
52- 56 F5.1 km/s e_VDE Error on VDE (lower value)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28 I1 --- Nz Number images
30- 33 I4 Kibyte size Size of FITS file
35- 77 A43 --- FileName Name of FITS file, in subdirectory fits
79-177 A99 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Leila Godinaud, leila.godinaud(at)cea.fr
(End) Patricia Vannier [CDS] 22-Sep-2023