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Register a new userHigh-Energy X-rays from J174545.5-285829, the Cannonball: A Candidate Pulsar Wind Nebula Associated with Sgr A East
أشعة إكس ذات طاقة عالية من J174545.5-285829، الكرة المدفعية: نبئ نبئ الريح النبئية المتوقعة مرتبطة بسجر أ شرق
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نحن نقدم الكشف بشكل صريح للإشعاع الغير حراري حتى 30 كيلو فولت من الكانون بول، وهو ظهور إشعاعي متجمع على عدد قليل من الأقدام بالقرب من مركز المجرة، باستخدام مقطع نوستار الإشعاعي. الكانون بول هو مركب نبطي كبير السرعة (vproj~500 كم / ث) مع نبطية ريح النبط القطبية (PWN) الموجودة على بعد ~2 شمال شرق من Sgr A *، خارج غطاء الراديو لمؤثر النيزك الشهير سجيتاريوس A (Sgr A) الشرقي. طيف الإشعاع الغير حراري الذي قيس حتى 30 كيلو فولت يتم تحديده بشكل جيد بواسطة قوة Gamma ~ 1.6، وهو عادي ل PWN، ولديه لومينوسية الإشعاع 3-30 كيلو فولت = 1.3e34 إرج / ث. يشير النتائج الطيفية والمكانية التي تم الحصول عليها من البيانات الإشعاعية والراديو بشكل قوي إلى نبطي هارب نشط نشأ في حدث Sgr A East النيزك. لم نجد أي إشارة مضطربة من الكانون بول. تسمح المقاطع النوستار لنا بإخلاء الحكم على مجال المغناطيسي ل PWN وتظهر أنه يتوافق مع الحد الأدنى الذي تم الحصول عليه من الملاحظات الراديو.
We report the unambiguous detection of non-thermal X-ray emission up to 30 keV from the Cannonball, a few-arcsecond long diffuse X-ray feature near the Galactic Center, using the NuSTAR X-ray observatory. The Cannonball is a high-velocity (vproj~500 km/s) pulsar candidate with a cometary pulsar wind nebula (PWN) located ~2 north-east from Sgr A*, just outside the radio shell of the supernova remnant Sagittarius A (Sgr A) East. Its non-thermal X-ray spectrum, measured up to 30 keV, is well characterized by a Gamma~1.6 power-law, typical of a PWN, and has an X-ray luminosity of L(3-30 keV)=1.3e34 erg/s. The spectral and spatial results derived from X-ray and radio data strongly suggest a runaway neutron star born in the Sgr A East supernova event. We do not find any pulsed signal from the Cannonball. The NuSTAR observations allow us to deduce the PWN magnetic field and show that it is consistent with the lower limit obtained from radio observations.
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We report on a discovery of a diffuse nebula containing a pointlike source in the southern blowout region of the Cygnus Loop supernova remnant, based on Suzaku and XMM-Newton observations. The X-ray spectra from the nebula and the pointlike source are well represented by an absorbed power-law model with photon indices of 2.2+/-0.1 and 1.6+/-0.2, respectively. The photon indices as well as the flux ratio of F_nebula/F_pointlike ~ 4 lead us to propose that the system is a pulsar wind nebula, although pulsations have not yet been detected. If we attribute its origin to the Cygnus Loop supernova, then the 0.5-8 keV luminosity of the nebula is computed to be 2.1e31 (d/540pc)^2 ergs/s, where d is the distance to the Loop. This implies a spin-down loss-energy E_dot ~ 2.6e35 (d/540pc)^2 ergs/s. The location of the neutron star candidate, ~2 degrees away from the geometric center of the Loop, implies a high transverse velocity of ~1850 (d/540pc)(t/10kyr)^{-1} km/s, assuming the currently accepted age of the Cygnus Loop.
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In this work, we study the X-ray bow-shock nebula powered by the mature pulsar PSR B1929+10 using data from XMM-Newton, with an effective exposure of $sim$ 300 ks, offering the deepest investigation of this system thus far. We found the X-ray axial outflow extends as long as $sim$ 8 arc minute behind the proper motion direction, which is a factor of two longer than the result reported in the previous study. Furthermore, we found evidence of two faint lateral outflows extending laterally with respect to the proper motion. We also found indications of spectral hardening along the axial outflow, suggesting that certain acceleration processes might occur along this feature.
The first detected gravitational wave GW170817 from a binary neutron star merger is associated with an important optical transient AT 2017gfo, which is a direct observation of kilonova. Recent observations suggest that the remnant compact object of the binary neutron star merger associated with GW170817/GRB 170817A may be a stable long-lived magnetized neutron star. In this situation, there would be a pulsar wind nebula (PWN) embedded inside the dynamic ejecta. The PWN emission may be absorbed by the ejecta or leak out of the system. We study the effect of the PWN emission on the observed light curves and radiation spectra. Different from previous works, the absorption and leakage of the PWN emission are all involved in our model, where the absorption of the PWN emission heats up the ejecta and alters its radiation. It is found that the characteristic emission of the embedded PWN quickly evolves. For the multiband and long-term observations of AT 2017gfo, we find that the dynamic ejecta with a PWN emission can fit the observational data very well, especially for the light curves at $tsim 5$ days and those in the late phase. In addition, our model can naturally generate the thermal to nonthermal spectrum evolution of AT 2017gfo. Our fitting result suggests that a PWN is embedded in the AT 2017gfo.
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