jeudi 24 octobre 2019

Nice paper on jets in an LMXB

LMXB: low mass x-ray binary; i.e. as low mass star and a stellar-mass black hole in orbit around each other. Emits copious amounts of x-ray radiation.

Based in Paice+ (2019), "A black hole X-ray binary at ∼100 Hz: multiwavelength timing of MAXI J1820+070 with HiPERCAM and NICER" (link to MNRAS-not-paywalled paper).

I am NOT a fan of PhysOrg, but in this case their reprinting of the University of Southampton's PR is well worth it, "Violent flaring revealed at the heart of a black hole system" (link).

The black hole is surrounded by an accretion disk, with mass streaming in from the doomed low mass star in the binary. By a combination of processes still not fully understood, a pair of back-to-back jets emerges in the pole directions of the accretion disk. Matter in these jets travels at highly relativitic speeds (at least initially). The same (or very similar) processes operate in AGNs (active galactic nuclei), with super-massive black hole (SMBH) accretion disks fed by gas and dust (and the occasional unlucky star); in some elliptical galaxies, the jets can extend millions of light years. You may recall that recently the "silhouette" of the SMBH in M87's nucleus was imaged.

Being a whole lot closer than M87 (or even our own galaxy's SgrA*), MAXI J1820+070 should permit better resolution of the various components and tease apart the main physical processes that produce the light, x-rays, etc that we see.

Hat-tip to Sol88 (who posted a link, ostensibly in support of something very different!). :jaw-dropp


via International Skeptics Forum https://ift.tt/2qAbTUf

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