2016
Maggi P, Hirschi R, Haberl F, Vasilopoulos G, Pietsch W, Greiner J, Kavanagh JP, Sasaki M, Bozzetto ML, Filipovic MD, et al. X-raying supernova remnants in the Magellanic Clouds. In: ; 2016. pp. 81.
WebsiteAbstractThe Magellanic Clouds (MCs) offer an ideal laboratory for the study of the SNR population in star-forming galaxies, since they are relatively nearby and free of large absorption. Both the LMC and SMC have been targeted by large XMM-Newton surveys, which, combined with archival observations, provide the best dataset to systematically study the X-ray emission of their numerous SNRs (∼ 60 in the LMC, ∼ 20 in the SMC). In this talk, I will highlight the results from this homogeneous analysis, which allows for the first time meaningful comparisons of temperature, chemical composition, and luminosity of SNRs in the MCs. The SNRs can be used as probes of their host galaxies: We measured chemical abundances in the hot phase of the LMC, and constrained the ratio of core-collapse to type Ia SN rates. The X-ray luminosity function of SNRs in the MCs are compared to those in other Local Group galaxies with different metallicities and star formation properties. Finally, we present a new population of evolved type Ia SNRs that was discovered recently in the MCs via their iron-rich X-ray emission.
Maggi P, Haberl F, Kavanagh PJ, Sasaki M, Bozzetto LM, Filipovic MD, Vasilopoulos G, Pietsch W, Points SD, Chu Y-H, et al. VizieR Online Data Catalog: X-ray supernova remnants in LMC (Maggi+, 2016). [Internet]. 2016;358:J/A+A/585/A162.
WebsiteAbstractThe processing of all available XMM-Newton data in the LMC region, and those of the VLP survey in particular, was done with the data reduction pipeline developed in our research group over several years. Various non-X-ray data were used to supplement the XMM-Newton observations. They allow us to assess e.g. the relation between the population of SNRs and large scale structure of the LMC, or to evaluate doubtful candidates in the sample compilation. We compiled a sample of 59 definite SNRs, cleaned of misclassified objects and doubtful candidates. (2 data files).
Vasilopoulos G.
A pulsating, possible type Ia supernova progenitor in the Large Magellanic. [Internet]. 2016:115.
WebsiteAbstractWe request a 50 ks observation of a pulsating (P~170 s), accretingwhite dwarf binary located in the Large Magellanic Cloud. The systemwas serendipitously detected off-axis during analysis of an archivalXMM-Newton observation (2013) that was severely contaminated by highbackground. Such objects are thought to be candidates for the progenitorsof type Ia supernovae, or may alternatively undergo accretion-inducedcollapse to form the neutron stars in some millisecond pulsars. Thenature of their short period oscillations remains unknown. The on-axisXMM-Newton observation proposed below would deliver a much improvedspectrum, allowing precise characterisation of the system.
Vasilopoulos G.
Inverstigating hard X-ray transients in the Magellanic Clouds. [Internet]. 2016:106.
WebsiteAbstractThe Magellanic Clouds harbour a large sample of Be/X-ray binariesat a moderate and well known distance with low Galactic foregroundabsorption. However, the transient nature of Be/X-ray binaries complicatesobservations in X-rays. Serendipitous detections of bright outburstsprovide rare chances for further investigation. We propose three triggeredXMM-Newton observations of new or unexplored systems to continue thebuild up of a large statistical sample of these sources.
Kennea J, Coe MJ, Laycock S, Bird T, Bartlett E, Townsend L, McBride V, Corbet R, Haberl F, Vasilopoulos G.
The Recent Outburst of SMC X-2 as seen by Swift, MAXI and NuSTAR. In: Vol. 15. ; 2016. pp. 120.12.
WebsiteAbstractWe present results from the latest outburst of the Be/X-ray binary system SMC X-2, which in late 2015 entered it's first X-ray outburst since 2000. SMC X-2 was first discovered in 1977 by the SAS-3 satellite, and hosts a 2.37s period pulsar. Regular, almost daily, Swift observations of SMC X-2 were performed during the entirety of the latest outburst, from first detection by MAXI to it’s rapid turn off and return back to quiescence. These observations have allowed us to measure with the flux, spectral and temporal properties of SMC X-2. Timing analysis of observation by the Swift X-ray telescope allowed us to track the evolution of the pulsar spin period, and in addition modeling of the orbital parameters of the system by measuring changes in the pulsar spin period due to Doppler effects. In addition we report on an observation of SMC X-2 taken with NuSTAR, which allowed both to better measure the continuum fit above 10 keV, and to perform a sensitive measure of the pulse profile and period of the source.
Antonopoulou D, Vasilopoulos G, Espinoza CM.
Swift detection of pulsations from PSR J1119-6127 promptly after its July 27th 2016 burst. [Internet]. 2016;9282:1.
WebsiteAbstractPSR J1119-6127 is a rotationally-powered (RP) pulsar whose pulsations are detected in radio, X-rays and gamma-rays. It is a high magnetic field neutron star, with an inferred dipole field strength of about 4 & sdot;1013 G. On July 27 it exhibited a strong X-ray burst, detected by Swift/BAT (ATel #9274) and Fermi/GBM (GCN Circular #19736).
Vasilopoulos G, Haberl F, Antoniou V, Zezas A.
X-ray outburst of XMMU J004855.5-734946: confirmation as a Be/X-ray binary pulsar. [Internet]. 2016;9229:1.
WebsiteAbstractXMMU J004855.5-734946 is a candidate BeXRB system in the Small Magellanic Cloud (SMC, Haberl & Sturm 2016, A & A, 586, 81). The system was detected in a recent 45 s Swift/XRT observation on 2016-06-24 as part of a routine Swift/XRT survey of the SMC (ATel #9197).
Vasilopoulos G, Haberl F, Delvaux C, Sturm R, Udalski A.
Multi-wavelength properties of IGR J05007-7047 (LXP 38.55) and identification as a Be X-ray binary pulsar in the LMC. [Internet]. 2016;461:1875 - 1884.
WebsiteAbstractWe report on the results of a ∼40-d multi-wavelength monitoring of the Be X-ray binary system IGR J05007-7047 (LXP 38.55). During that period the system was monitored in the X-rays using the Swift telescope and in the optical with multiple instruments. When the X-ray luminosity exceeded 1036 erg s-1 we triggered an XMM-Newton ToO observation. Timing analysis of the photon events collected during the XMM-Newton observation reveals coherent X-ray pulsations with a period of 38.551(3) s (1σ), making it the 17th known high-mass X-ray binary pulsar in the LMC. During the outburst, the X-ray spectrum is fitted best with a model composed of an absorbed power law (Γ = 0.63) plus a high-temperature blackbody (kT ∼2 keV) component. By analysing ∼12 yr of available OGLE optical data we derived a 30.776(5) d optical period, confirming the previously reported X-ray period of the system as its orbital period. During our X-ray monitoring the system showed limited optical variability while its IR flux varied in phase with the X-ray luminosity, which implies the presence of a disc-like component adding cooler light to the spectral energy distribution of the system.
Maggi P, Haberl F, Kavanagh PJ, Sasaki M, Bozzetto LM, Filipović MD, Vasilopoulos G, Pietsch W, Points SD, Chu Y-H, et al. The population of X-ray supernova remnants in the Large Magellanic Cloud. [Internet]. 2016;585:A162.
WebsiteAbstract 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 NCC/NIa=1.35(-0.24+0.11), 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. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.