Three new high-mass X-ray binaries in the Large Magellanic Cloud

The Magellanic Clouds host a large population of high-mass X-ray binary (HMXB) systems, but although the Large Cloud (LMC) is an order magnitude more massive than Small Cloud, significantly fewer HMXBs are known. We conducted search for new in XMM-Newton observations, which we performed to investigate supernova remnant candidates supergiant shells LMC5 and LMC7. three observed fields located regions, were little explored X-rays before. analysed data look sources with hard spectrum counterparts optical colours brightness typical HMXBs. report discovery Be/X-ray binaries, two them showing pulsations their flux. With luminosity 6.5e34 erg/s, XMMU J045315.1-693242 LMC7 was relatively faint. long-term OGLE I-band light curve V = 15.5 mag counterpart suggests 49.6 day or 24.8 orbital period system. J045736.9-692727, also brighter 5.6e35 erg/s power-law photon index 0.63. flux revealed clear 317.7 s. obtained high resolution spectra from 14.2 using SALT-HRS spectrograph. Halpha Hbeta emission complex line profiles equivalent widths -8.0 A -1.3 A, respectively. shows series four strong outbursts followed by sudden drop 1 within 73-165 days recovery level before outbursts. RX J0524.2-6620, previously classified as candidate, at eastern part LMC5. 360.7 s pulsations. (abridged)