Jets from Giant Black Holes

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ALMA Probes Mysteries of Jets from Giant Black Holes

Two international teams of astronomers have used the power of the Atacama Large Millimeter/submillimeter Array (ALMA) to focus on jets from the huge black holes at the centres of galaxies and observe how they affect their surroundings. They have respectively obtained the best view yet of the molecular gas around a nearby, quiet black hole and caught an unexpected glimpse of the base of a powerful jet close to a distant black hole.

There are supermassive black holes — with masses up to several billion solar masses — at the hearts of almost all galaxies in the Universe, including our own galaxy, the Milky Way. In the remote past, these bizarre objects were very active, swallowing enormous quantities of matter from their surroundings, shining with dazzling brilliance, and expelling tiny fractions of this matter through extremely powerful jets. In the current Universe, most supermassive black holes are much less active than they were in their youth, but the interplay between jets and their surroundings is still shaping galaxy evolution.

Two new studies, both published today in the journal Astronomy & Astrophysics, used ALMA to probe black hole jets at very different scales: a nearby and relatively quiet black hole in the galaxy NGC 1433 and a very distant and active object called PKS 1830-211.

Source

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Zooming in on the active galaxy NGC 1433

This video sequence starts with a broad view of the southern sky and zooms in on the faint constellation of Horologium (The Clock). When we get closer we start to see a striking spiral galaxy known as NGC 1433. The central part of this galaxy hosts a supermassive black hole and observations of its surroundings using ALMA have revealed both a spiral structure to the molecular gas as well as a newly discovered outflow of material.

Credit: ALMA (ESO/NAOJ/NRAO)/F. Combes

Source: ESO Observatory

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Zooming in on the distant active galaxy PKS 1830-211

This video sequence starts with a broad view of the southern Milky Way and zooms in on a region close to the centre of the galaxy. When we get closer we start to see huge numbers of stars and, apparently nestled amongst them, but really vastly further away, the remote active galaxy PKS 1830-211 can just be seen. This unusual object is gravitationally lensed by a closer galaxy and appears split into two parts, as can be seen in the ALMA observations that are shown in red at the end of this sequence.

Credit: ALMA (ESO/NAOJ/NRAO)/I. Martí-Vidal/Nick Risinger (skysurvey.org)

Source: ESO Observatory

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Artist's impression of ALMA observations of a gravitationally-lensed supermassive black hole

This artist’s representation shows the gravitationally-lensed black hole PKS1830-211 and the sudden flaring seen with ALMA when material enters the base of the jet, close to the black hole itself. Orange indicates the jet seen in radio waves; green, blue, and red are the (changing) images seen with ALMA and the white flashes represent gamma rays.

Credit: ALMA (ESO/NAOJ/NRAO)/I. Martí-Vidal/MERLIN (University of Manchester, Jodrell Bank Observatory, STFC)

Source: ESO Observatory

Edited November 13, 2013 by Waspie_Dwarf