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The 2-7 keV Chandra images of the K3 PWN on various spatial scales (a-c) and a SUMSS 843 MHz image (d). The images are smoothed and the scales are adjusted for better legibility. The point-source-removed and exposure-corrected Chandra images are constructed following a CIAO science thread. The position of J1420 is denoted by a green cross. (a) Chandra image on a 40″ × 40″ scale. In addition to the two knots denoted in cyan, a faint jet (not visible in this panel) and a torus are marked. (b) Chandra image on a ¢ ´ ¢ 2 2 scale. The torus and the jet structures are shown in white and cyan ellipses, respectively. (c) Chandra image on a ¢ ´ ¢ 16 16 scale. A long northern tail region is denoted by a yellow ellipse and two short tails are marked. Regions of the Fermi-LAT (0° . 123; radius of a disk model) and H.E.S.S. (0° . 08; 1σ width of a Gaussian model) counterparts are displayed in cyan and white circles, respectively. (d) SUMSS 843 MHz image (Mauch et al. 2003). The image was downloaded from the Skyview webpage and truncated to match the X-ray emission region in panel (c). Note also that a box region in the lower right corner is excised because it contains a bright unrelated point source. The pulsar, northern X-ray tail, and Fermi-LAT and H.E.S.S. regions are overlaid for comparison.
Source publication
We present a detailed analysis of broadband X-ray observations of the pulsar PSR J1420−6048 and its wind nebula (PWN) in the Kookaburra region with Chandra, XMM-Newton, and NuSTAR. Using the archival XMM-Newton and new NuSTAR data, we detected 68 ms pulsations of the pulsar and characterized its X-ray pulse profile, which exhibits a sharp spike and...
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... was done by following a procedure in the CIAO science thread. 8 We then adjusted the image scales and bins to identify structures in the PWN on various spatial scales (Figure 2). ...
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... a 40″ × 40″ scale, we identified two knots at 3″ and 7″ from the pulsar (Knot 1 and Knot 2; Figure 2(a)); compared to nearby backgrounds, the knots were detected at ∼3σ significance. Note that Knot 1 is listed in the Chandra source catalog, 9 but we do not find an IR or optical counterpart in the 2MASS and USNO catalogs. ...
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... the knots appear to be more extended than nearby point sources with similar counts. Note also that there seems to be a slightly elongated structure (short and parallel to-but just east of-the jet indicated in Figure 2(b)), but this structure was detected only at the 2.5σ level. An image of a ¢ ´ ¢ 2 2 region near the pulsar is displayed in Figure 2(b). ...
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... also that there seems to be a slightly elongated structure (short and parallel to-but just east of-the jet indicated in Figure 2(b)), but this structure was detected only at the 2.5σ level. An image of a ¢ ´ ¢ 2 2 region near the pulsar is displayed in Figure 2(b). In this image, the torus structure in the east-west direction identified by Ng et al. (2005) is clearly visible. ...
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... addition, we found a narrow jet-like (∼20″) feature extending in the northeast direction. The jet-like structure is fainter but detected at a 3σ level, having 172 events in the 1-10 keV band within a 7″ × 17″ ellipse (excluding the pulsar and torus emission; Figure 2(b)) which contains estimated 119 background counts. ...
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... larger-scale image is displayed along with VHE emission regions (H.E.S.S. Collaboration et al. 2018;Abdollahi et al. 2020) in Figure 2(c). The image reveals a prominent ∼7′ tail (denoted as "Tail") and two short tails in the northwest direction. ...
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... bright southern region and the northern "Tail" were also identified in our inspection of XMM-Newton MOS images. The "Tail" appears to partially overlap with a radio structure ( Figure 2(d); see also Van Etten & Romani 2010). 10 The VHE emission regions are centered at 2′-3′ north of the pulsar (white and cyan circles in Figure 2(c)) and also overlap Figure 1. ...
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... "Tail" appears to partially overlap with a radio structure ( Figure 2(d); see also Van Etten & Romani 2010). 10 The VHE emission regions are centered at 2′-3′ north of the pulsar (white and cyan circles in Figure 2(c)) and also overlap Figure 1. Top: 1-10 keV XMM-Newton (red) and 3-30 keV NuSTAR (black; FPMA and FPMB combined) pulse profiles. ...
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... this section, we analyze X-ray spectra of the K3 PWN and its substructures that were identified in the Chandra images ( Figure 2). The spectral softening measured for K3 (Van Etten & Romani 2010;Kishishita et al. 2012) implies a spectral curvature in its spatially integrated spectrum which may be detected in the broadband X-ray data taken with NuSTAR (e.g., Madsen et al. 2015a). ...
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... should be noted that we have again used the angr abundances for the quoted N H value, to compare to previously published studies and be consistent throughout. Using the newer Wilms abundances (Wilms et al. 2000) gives, as expected, a higher column density of (6.94 ± 0.55) × 10 22 cm −2 but does not change the other spectral parameters. ...
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... measured the X-ray spectra of the substructures found in the Chandra image: the torus, jet, and northern tail (Figure 2). The spectra of the other structures (e.g., knots) were difficult to measure due to the paucity of counts. ...
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... spectra of the other structures (e.g., knots) were difficult to measure due to the paucity of counts. To extract spectra, we used elliptical regions with sizes of 10″ × 7″ (excluding an R = 2″ region around the pulsar; Figure 2(a)), 7″ × 17″ (Figure 2(b)), and ¢ ´ ¢ 2 6 (Figure 2(c)) for the torus, jet, and tail, respectively. Background spectra were extracted in the vicinity of the source regions. ...
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... spectra of the other structures (e.g., knots) were difficult to measure due to the paucity of counts. To extract spectra, we used elliptical regions with sizes of 10″ × 7″ (excluding an R = 2″ region around the pulsar; Figure 2(a)), 7″ × 17″ (Figure 2(b)), and ¢ ´ ¢ 2 6 (Figure 2(c)) for the torus, jet, and tail, respectively. Background spectra were extracted in the vicinity of the source regions. ...
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... spectra of the other structures (e.g., knots) were difficult to measure due to the paucity of counts. To extract spectra, we used elliptical regions with sizes of 10″ × 7″ (excluding an R = 2″ region around the pulsar; Figure 2(a)), 7″ × 17″ (Figure 2(b)), and ¢ ´ ¢ 2 6 (Figure 2(c)) for the torus, jet, and tail, respectively. Background spectra were extracted in the vicinity of the source regions. ...
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... torus-jet structure we found (Figure 2(a)) can be interpreted as the termination shock (e.g., Ng et al. 2005) and a collimated jet. The torus radius of ∼5″ corresponds to 0.14 pc for the assumed distance of 5.6 kpc and is consistent with the size of a termination shock formed by pressure balance (e.g., Kargaltsev & Pavlov 2008). ...
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... long northern tail detected by Suzaku was interpreted as a trail of the pulsar that had been born 3′ northwest at the center of an apparent radio shell (Van Etten & Romani 2010, see also Figure 7). In this scenario, the three tails in the Chandra image (Figure 2(c)) may be related to the pulsar's polar and equatorial outflows (Figure 7 bottom) analogous to those observed in Geminga (Posselt et al. 2017). In this picture, the much more prominent (top) tail ("Tail" in Figure 2(c)) is the bent, originally approaching polar jet, the middle tail is the equatorial outflow, and the bottom tail is the bent counter jet (Figure 7 bottom). ...
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... this scenario, the three tails in the Chandra image (Figure 2(c)) may be related to the pulsar's polar and equatorial outflows (Figure 7 bottom) analogous to those observed in Geminga (Posselt et al. 2017). In this picture, the much more prominent (top) tail ("Tail" in Figure 2(c)) is the bent, originally approaching polar jet, the middle tail is the equatorial outflow, and the bottom tail is the bent counter jet (Figure 7 bottom). The putative radio shell discovered by Van Etten & Romani (2010) might be compressing the PWN in the southeast, and the narrow inner jets (Figure 2 middle) might have been blocked by the shell, turning into the broad tails over the course of the pulsar's motion (e.g., Figure 7, bottom). ...
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... this picture, the much more prominent (top) tail ("Tail" in Figure 2(c)) is the bent, originally approaching polar jet, the middle tail is the equatorial outflow, and the bottom tail is the bent counter jet (Figure 7 bottom). The putative radio shell discovered by Van Etten & Romani (2010) might be compressing the PWN in the southeast, and the narrow inner jets (Figure 2 middle) might have been blocked by the shell, turning into the broad tails over the course of the pulsar's motion (e.g., Figure 7, bottom). The compressed southern region would have stronger magnetic field and hence brighter synchrotron emission. ...
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... false-color image of the source (top) and a schematic (bottom) that shows our speculation on the emission components. (Top) A radio and X-ray image of the PWN: red for the SUMSS 843 GHz, green for the Chandra 1-7 keV, and blue for the NuSTAR 3-20 keV image (see Figures 2 and 3). (Bottom) Structures (tails and southern bright region) seen in the Chandra image are presented in green, and the apparent radio shell structure seen in the SUMSS image is depicted in red. ...
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... black dotted arrow shows a suggested pulsar's trajectory (e.g., Van Etten & Romani 2010). clear that the K3 PWN has some substructures (Figure 2) and is not spherically symmetric (Figure 7). Moreover, the particle flow in the PWN may be very complex due to pulsar motion and reverse shock compression (e.g., Van Etten & Romani 2010, Section 4.2). ...
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