Quasars & “Active” Galaxies

Июль 25, 2022

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Quasars & “Active” Galaxies

Содержание

2. Maarten Schmidt identified the first quasar 3C273 in 1963 z = 0.158 => 2 billion lyr
3. 3C48 was the second quasar, found soon after z = 0.367 => 4 billion lyr
4. Comparing the resolution of HST with a ground-based photo Ground Hubble Space Telescope
5. With the high resolution of HST, we could subtract off the bright star-like quasar to reveal
6. Many quasars are found in colliding galaxies; mergers “trigger” quasars High-resolution HST images of QSOs reveal
7. Black holes can shine by having an “accretion disk”
8. Seyfert galaxies are AGNs of intermediate brightness in galaxies that are not disturbed Seyfert: NGC 5548
9. M87: A nearby giant elliptical galaxy with central AGN and radio “jet” 3 billion M◉ central
10. 3 billion M◉ central black hole M87 nearby giant elliptical M87: A nearby giant elliptical galaxy
11. A pair of galaxies in the process of merging, each with its own black hole and
12. Cygnus A: one of the largest radio galaxies in the Universe Z = 0.056 500,000 light
13. Radio galaxies shine by emitting synchrotron radiation
14. Cygnus A: one of the largest radio galaxies in the Universe Z = 0.056 500,000 light
15. 3 billion M◉ central black hole M87 nearby giant elliptical M87: A nearby giant elliptical galaxy
16. Weaker radio galaxies have “fluffier” radio lobes The peculiar nearby elliptical NGC 1316 with radio lobes
17. Spheroids host massive central black holes, which power quasars and other kinds of active galactic nuclei
18. Our Milky Way observed with adaptive optics at the 10-meter Keck telescope
19. Stars in orbit about the Milky Way’s BH give a mass of 3 million solar masses
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Слайд 2

Maarten Schmidt identified the first quasar 3C273 in 1963
z = 0.158

=> 2 billion lyr

Diffraction spikes produced in telescope; only for point source. Shows quasar is star-like.

Слайд 3

3C48 was the second quasar, found soon after
z = 0.367 =>

4 billion lyr

Слайд 4

Comparing the resolution of HST with a ground-based photo
Ground
Hubble Space Telescope

Слайд 5

With the high resolution of HST, we could subtract off the

bright star-like quasar to reveal the underlying galaxy clearly for the first time

Слайд 6

Many quasars are found in colliding galaxies; mergers “trigger” quasars
High-resolution HST

images of QSOs reveal host galaxies. The brightest QSOs are 1000 times the brightness of the Milky Way.

Слайд 7

Black holes can shine by having an “accretion disk”

Слайд 8

Seyfert galaxies are AGNs of intermediate brightness in galaxies that are

not disturbed

Seyfert: NGC 5548

Normal galaxy: NGC 3277

Quasar-like point source

The relationship of Seyferts to quasars is unclear, but they are believed to also shine by active black holes.

Слайд 9

M87: A nearby giant elliptical galaxy with central AGN and radio

“jet”

3 billion M◉ central black hole

M87 nearby giant elliptical

Слайд 10

3 billion M◉ central black hole
M87 nearby giant elliptical
M87: A

nearby giant elliptical galaxy with central AGN and radio “jet”

Слайд 11

A pair of galaxies in the process of merging, each with

its own black hole and radio jets

An optical image showing the galaxies as two fuzzy blobs superimposed on the VLA radio image showing the radio jets.

25,000 lyr

Z = 0.023 => 320 million lyr

Слайд 12

Cygnus A: one of the largest radio galaxies in the Universe

Z = 0.056

500,000 light years

Слайд 13

Radio galaxies shine by emitting synchrotron radiation

Слайд 14

Cygnus A: one of the largest radio galaxies in the Universe

Z = 0.056

500,000 light years

Beam of charged particles and magnetic field ejected near the speed of light

Particles hit gas outside galaxy and slow down; inflate a cavity in gas

Слайд 15

3 billion M◉ central black hole
M87 nearby giant elliptical
M87: A

nearby giant elliptical galaxy with central AGN and radio “jet”

Слайд 16

Weaker radio galaxies have “fluffier” radio lobes
The peculiar nearby elliptical NGC

1316 with radio lobes

Слайд 17

Spheroids host massive central black holes, which power quasars and other

kinds of active galactic nuclei (AGNs)

Слайд 18

Our Milky Way observed with adaptive optics at the 10-meter Keck

telescope

Слайд 19

Stars in orbit about the Milky Way’s BH give a mass

of 3 million solar masses