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XMM search for $X$-ray emission from the black hole candidate MACHO-96-BLG-5

A. A. Nucita·F. De Paolis·G. Ingrosso·D. Elia·J. de Plaa·J. S. Kaastra
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Abstract

MACHO-96-BLG-5 is a microlensing event observed towards the bulge of the Galaxy with exceptionally long duration of $\sim 970$ days. The microlensing parallax fit parameters were used to estimate the lens mass $M=6^{+10}_{-3}$ M$_{\odot}$ and its distance $d$ which results to be in the range 0.5 kpc - 2 kpc. The upper limit on the absolute brightness for main-sequence stars of the same mass is less than 1 $L_{\odot}$ so that the lens is a good black hole candidate. If it is so, the black hole would accrete by interstellar medium thereby emitting in the $X$-ray band. Here, the analysis of an {\it XMM} deep observation towards MACHO-96-BLG-5 lens position is reported. Only an upper limit (at 99.8% confidence level) to the $X$-ray flux from the lens position of $9.10\times 10^{-15}$-- $1.45\times 10^{-14}$ erg cm$^{-2}$ s$^{-1}$ in the energy band $0.2-10$ keV has been obtained from that deep observation allowing to constrain the putative black hole accretion parameters.

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A. A. Nucita, F. De Paolis, G. Ingrosso, D. Elia, J. de Plaa, J. S. Kaastra. 2006-08-31. XMM search for $X$-ray emission from the black hole candidate MACHO-96-BLG-5. https://arxiv.org/abs/astro-ph/0608692

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