Australian Sky & Telescope — January 01, 2018

8 AUSTRALIAN SKY & TELESCOPE January 2018

WEBB TELESCOPE

LAUNCH DELAYED

NASA/DESIREE STOVER

NEWS NOTES

Technicians lift the James Webb Space

Telescope’s main mirror assembly inside a

clean room at NASA’s Goddard Space Flight

Center. The 18-segment mirror is designed

to capture infrared light from the earliest

galaxies, and planetary systems forming

around stars.

THE LONG-AWAITED James Webb

Space Telescope (JWST) — successor

to the Hubble Space Telescope — will

now launch between March and

June 2019. Integrating and testing

various spacecraft elements, including

the five-layered sunshield, is taking

longer than expected and has forced

a roughly 6-month launch delay from

the original October 2018. The project

will nevertheless remain within the

budget that NASA agreed to in 2011. The

telescope and its science instruments are

currently undergoing extensive testing.

The final step will be to integrate the

telescope onto the spacecraft and test

the fully assembled observatory before

it is launched to orbit the Sun at the L

Lagrangian point, 1.5 million km from

Earth. ■ MONICA YOUNG

Supermassive black hole twins do the tango

NEW OBSERVATIONS reported in

the October 2017 Nature Astronomy

journal reveal a double radio source at

the centre of Markarian 533, a face-on

spiral galaxy in Pegasus. The emission

might come from a tight pair of

supermassive black holes.

Preeti Kharb (National Centre

for Radio Astrophysics, India) and

colleagues used the Very Long Baseline

Array to resolve two sources at a

frequency of 15 gigahertz, which might

emanate from two supermassive black

holes with a combined mass of 40

million Suns. The putative pair orbit

each other only a light-year apart, the

closest candidate black-hole binary to

be detected via direct imaging.

However, since the VLBI

observations only detect the double

source at a single frequency, the spectra

are not yet known, making it difficult

to rule out alternatives. It’s possible,

for example, that one source is a black

hole, while the other is the base of a jet

rather than a black hole companion.

But some factors, including the

unusual Z shape of the galaxy’s

stubby radio-emitting jets, favour the

double-black-hole scenario. If future

observations confirm the supermassive

binary, it will provide an important

perspective on how such systems form

and evolve. ■ MONICA YOUNG