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Register a new userA Detailed Observation of a LMC Supernova Remnant DEM L241 with XMM-Newton
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Aya Bamba
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We report on an {it XMM-Newton} observation of the supernova remnant (SNR) object{DEM L241} in the Large Magellanic Cloud. In the soft band image, the emission shows an elongated structure, like a killifish, with a central compact source. The compact source is point-like, and named as XMMU J053559.3$-$673509. The source spectrum is well reproduced with a power-law model with a photon index of $Gamma = 1.57$ (1.51--1.62) and the intrinsic luminosity is $2.2times 10^{35} mathrm{ergs s^{-1}}$ in the 0.5--10.0 keV band, with the assumed distance of 50 kpc. The source has neither significant coherent pulsations in $2.0times 10^{-3}$ Hz--8.0 Hz, nor time variabilities. Its luminosity and spectrum suggest that the source might be a pulsar wind nebula (PWN) in DEM L241. The spectral feature classifies this source into rather bright and hard PWN, which is similar to those in Kes 75 and B0540$-$693. The elongated diffuse structure can be divided into a ``Head and ``Tail, and both have soft and line-rich spectra. Their spectra are well reproduced by a plane-parallel shock plasma ({it vpshock}) model with a temperature of 0.3--0.4 keV and over-abundance in O and Ne and a relative under-abundance in Fe. Such an abundance pattern and the morphology imply that the emission is from the ejecta of the SNR, and that the progenitor of DEM L241 is a very massive star, more than 20 Msun. This result is also supported by the existence of the central point source and an OB star association, LH 88. The total thermal energy and plasma mass are $sim 4times 10^{50}$ ergs and $sim 200$ Msun, respectively.
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A Chandra observation of the Large Magellanic Cloud supernova remnant DEM L241 reveals an interior unresolved source which is probably an accretion-powered binary. The optical counterpart is an O5III(f) star making this a High-Mass X-ray Binary (HMXB) with orbital period likely to be of order tens of days. Emission from the remnant interior is thermal and spectral information is used to derive density and mass of the hot material. Elongation of the remnant is unusual and possible causes of this are discussed. The precursor star probably had mass > 25 solar masses
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