The population of X-ray supernova remnants in the Large Magellanic Cloud

Abstract

Aims. We present a comprehensive X-ray study of the population of supernova remnants (SNRs) in the Large Magellanic Cloud (LMC). Using primarily XMM-Newton observations, we conduct a systematic spectral analysis of LMC SNRs to gain new insight into their evolution and the interplay with their host galaxy. Methods. We combined all the archival XMM-Newton observations of the LMC with those of our Very Large Programme LMC survey. We produced X-ray images and spectra of 51 SNRs, out of a list of 59 objects compiled from the literature and augmented with newly found objects. Using a careful modelling of the background, we consistently analysed all the X-ray spectra and measure temperatures, luminosities, and chemical compositions. The locations of SNRs are compared to the distributions of stars, cold gas, and warm gas in the LMC, and we investigated the connection between the SNRs and their local environment, characterised by various star formation histories. We tentatively typed all LMC SNRs, in order to constrain the ratio of core-collapse to type Ia SN rates in the LMC. We also compared the column densities derived from X-ray spectra to H i maps, thus probing the three-dimensional structure of the LMC. Results. This work provides the first homogeneous catalogue of the X-ray spectral properties of SNRs in the LMC. It offers a complete census of LMC remnants whose X-ray emission exhibits Fe K lines (13% of the sample), or reveals the contribution from hot supernova ejecta (39%), which both give clues to the progenitor types. The abundances of O, Ne, Mg, Si, and Fe in the hot phase of the LMC interstellar medium are found to be between 0.2 and 0.5 times the solar values with a lower abundance ratio [α/Fe] than in the Milky Way. The current ratio of core-collapse to type Ia SN rates in the LMC is constrained to N CC /N Ia = 1.35( +0.11 −0.24 ), which is lower than in local SN surveys and galaxy clusters. Our comparison of the X-ray luminosity functions of SNRs in Local Group galaxies (LMC, SMC, M31, and M33) reveals an intriguing excess of bright objects in the LMC. Finally, we confirm that 30 Doradus and the LMC Bar are offset from the main disc of the LMC to the far and near sides, respectively.

Multi-frequency study of the newly confirmed supernova remnant MCSNR J0512−6707 in the Large Magellanic Cloud

“…Due to the lack of ejecta signatures, we cannot directly determine the supernova type from the X-ray spectrum. Indirect evidence for the explosion mechanism is found in the study of the local stellar population and star formation history study of Maggi et al (2015), which, because of the large number of nearby OB stars and recent star formation burst, suggest a core-collapse origin. This is consistent with the SNR evolution into a the wind-blown cavity suggested above.…”

“…We extracted FWC spectra from the same detector regions as the observational source and background spectra. The EPIC-pn and EPIC-MOS FWC spectra were fitted with the empirical models developed by Sturm (2012) and Maggi et al (2015), respectively. Since these spectral components are not subject to the instrumental response, we used a diagonal response in XSPEC.…”

“…Similarly, the absence of such a high mass stellar population and recent star formation burst would point to a Type Ia origin. While this typing method is not infallible (see Maggi et al 2015, for a detailed description of the method and caveats) it still offers a good indication of the likely SN type and has been…”

Supernova Remnants as Clues to Their Progenitors

“…This SNR has long been suspected to be a cavity explosion, and its bulk dynamics are hard to interpret without a fast, sustained outflow from the progenitor, with properties similar to those of accretion winds (Badenes et al, 2007;Williams et al, 2011). Yamaguchi et al (2014), plus DEM L71 (Maggi et al, 2016). The shaded regions represent theoretical predictions from Type Ia SNR models interacting with a uniform interstellar medium (Badenes et al, 2003(Badenes et al, , 2005: orange for the 56 Ni-poor delayed detonation model DDTg, blue for bright 56 Ni-rich delayed detonation model DDTa.…”

Spatial Distribution of Mg-Rich Ejecta in LMC Supernova Remnant N49b

“…In these spectral model fits of the region E spectrum we assumed the recent measurements of the LMC abundances for O, Ne, Mg, Si, and Fe (except for the Mg abundance in the ejecta component spectrum) based on the Chandra data of the LMC SNRs (Schenck et al 2016), while we adopted LMC abundance values by Russell & Dopita (1992) for other elements. We note that, for the LMC abundances, several measurements are available in the literature (e.g., Russell & Dopita 1992;Hughes et al 1998;Davies et al 2015;Maggi et al 2016;Schenck et al 2016).…”