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تسجيل مستخدم جديدA catalogue sample of low mass galaxies observed in X-rays with central candidate black holes
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We present a sample of $X$-ray selected candidate black holes in 51 low mass galaxies with $zle 0.055$ {and mass up to $10^{10}$ M$_{odot}$} obtained by cross-correlating the NASA-SLOAN Atlas with the 3XMM catalogue. {We have also searched in the available catalogues for radio counterparts of the black hole candidates and find that 19 of the previously selected sources have also a radio counterpart.} Our results show that about $37%$ of the galaxies of our sample host { an $X$-ray source} (associated to a radio counterpart) spatially coincident with the galaxy center, in agreement with { other recent works}. For these {it nuclear} sources, the $X$-ray/radio fundamental plane relation allows one to estimate the mass of the (central) candidate black holes which results to be in the range $10^{4}-2times10^{8}$ M$_{odot}$ (with median value of $simeq 3times 10^7$ M$_{odot}$ and eight candidates having mass below $10^{7}$ M$_{odot}$). This result, while suggesting that $X$-ray emitting black holes in low-mass galaxies may have had a key role in the evolution of such systems, makes even more urgent to explain how such massive objects formed in galaxies. {Of course, dedicated follow-up observations both in the $X$-ray and radio bands, as well as in the optical, are necessary in order to confirm our results
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