High energy Astrophysics

Mat Page

Mullard Space Science Lab, UCL

2. X-ray and -ray sources

2. The X-ray / -ray sources (the zoo)

• This lecture:• An exhaustive inventory of X-ray sources

• Why they emit X-rays

• Where they are in the sky

• Where they are in the electromagnetic spectrum

Slide 2

Images of the sun over its 11 year activity cycle from the Yohkoh Soft X-ray telescope

The Sun

X-ray luminosity 1019-1021 W

Slide 3

Planets, the moon and comets

Jupiter seen by Chandra

Jupiter at time of Shoemaker-Levy 9 impact (Rosat)

Slide 4

X-ray luminosity ~ 5x109 W

Planets, the moon and comets

The Moon!

You can also see the X-ray background in this picture!

Slide 5

X-ray luminosity ~ 4x106 W

Planets, the moon and comets

Comet Hyakutake!

Slide 6

X-ray luminosities 106-109W

Normal stars

Stars in the Stars in the open cluster open cluster NGC 2516 NGC 2516 (Rosat)(Rosat)

Slide 7

X-ray luminosities of up to 1024 W

Massive stars

The bright source in the centre of NGC 3606 is due to the colliding winds from massive stars

Slide 8

X-ray luminosities of up to 1026 W

Supernova remnants

Cas-A and Tycho supernova remnants (Chandra)

Slide 9

X-ray luminosities of up to 1030 W

Compact stars

This 5 hour time sequence from the Einstein observatory shows pulses of X-ray emission from the Crab pulsar

Slide 10

X-ray luminosities of up to 1029 W

Interacting binaries

Interacting binaries in the globular cluster 47-Tuc

Slide 11

X-ray luminosities of up to 1032 W

galaxies

M82 as seen by Chandra, with an optical image (in blue) superimposed in the right panel

Slide 12

X-ray luminosities of up to 1035 W

AGN

The quasar 3C273 and its X-ray jet as seen by Chandra

Slide 13

X-ray luminosities of up to 1039 W

Clusters of galaxies

Coma

Slide 14

X-ray luminosities of up to 1038 W

Luminosities

(W)

Slide 15

Some key points:

• Surprisingly, a whole host of objects have been detected as X-ray sources.

• Strong magnetic fields can accelerate particles to high velocities to produce X-ray emission, for example in the coronae of the Sun and other normal stars, and in planetary aurorae.

• Fast shock waves are another source of high energy emission, for example in supernova remnants and when stellar winds collide.

• The most luminous X-ray sources (AGN, clusters of galaxies, accreting binaries) are powered by gravitational potential energy.

Slide 16