Credit: Subaru Telescope

Is M82Many outflowing (1000 km/sec), escaping warm gas filaments , Shown in red

Cause is not so unusual: thousands of young stars and their supernova explosions (leave it for Alex), spread over this dwarf galaxy

Total energy produced is less than the starlight from the rest of the galaxy, and it emerges gradually, along directions of easiest escape (a slow boil)

An utterly more bizarre jet from M87

(HST image of this Giant Elliptical Galaxy in the nearby

Virgo Cluster

Nucleus of the galaxy

A highly collimated jet

More Surprises:1) the M87 jet produces the most powerful radio waves in Virgo2) its energetic radio lobes are enormous• Each zoom step is

roughly factor of 10X magnification

• Maps from the Very Large Array and a global interferrometer give light-year resolution

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3

4

5

6

M87’s jet is not the only one:

More Blasts from the past • 1960-70’s Radio-astronomers discovered a few

hundred such galaxies —completely unexpected

• The huge double lobes contain a prodigious amount of high-energy particles (e.g. electrons), which could only have been accelerated by a remarkably powerful, long-lived (Myrs) process

• By now many of them have escaped the galaxy, but they are still radiating energy by the synchrotron mechanism (when electrons spiral in a magnetic field at nearly the speed of light)

Most Powerful Radio Sources in Fornax and Cygnus

Center of galaxy

A pattern in these crimes.“What kind of monster…?”(Even Billions of) supernovae couldn’t possibly have done this!

Visible stars;Radio lobes

Where did these blasts originate?

• The maps are strongly suggestive: The giant lobes are the “smoke” of colossal explosions. Since the lobes always point back to well-collimated jets which start out in the galactic nucleus, that must be where all the power originated

…get a search warrant

Another nearby jet, in Centaurus

White=nearby peculiar elliptical galaxy, NGC 5128Blue/green=double radio lobes

Close-up of 1-sided jet emerging from the center; blue is X-rays, red is radio

Supercomputer Simulations

• In this model calculation, High-speed electron Jet starts horizontally from the left, and runs for 5.4 million years—

• Looks very realistic

Re-enact the crime

Proof: High-energy blasts are originating from some of

these galactic centers currently

• The jets have many lumps, suggestive of an erratic energy input.

• Repeated VLBI high-resolution mapping shows repeated (unpredictable) ejection of new radio blobs of high-energy particles start out at speeds of 0.98—0.99c

Several years of observations of M87’s jet—movie from J. Biretta

This is ready to go to the grand jury

New ejections usually come from galactic nuclei which are currently “active” (Blasts from Quasars)

• The famous radio jets are often just the tip of the iceberg: Far more power emerges from the Active Galactic Nucleus at high energies, including visible light, X-rays and extreme Gamma-rays; total can exceed output of all the stars—trillions of solar luminosities!

Jet from powerful Quasar 3C273

• AGN produces its power in a very compact region, since: R < c T ie only a few light-hours across, smaller than our Solar System!

• The massive central engine of AGN is the (bi-polar) high-energy particle accelerator, even if it’s often turned off

Gamma-ray flare erupts in 8 hours,1000X more powerful than the entire Milky Way galaxy

Compton Gamma Ray Observatory—Mattox, Malkan et al

The Quasar Connection: to understand jets, we must understand Active Galactic Nuclei

The crime boss behind the whole operation

HST Zoom of another jet from a nearby AGN

• Jet appears to emerge perpendi-cular to a gas disk around the galactic center

Innuendo

What is the AGN Central Engine? The Black Hole Theory

• Best jet model is (chaotic) energy release from magnetized matter in close (disk) orbits around a giant black hole (highly fuel efficient)

• Spinning disk of gas defines north and south polar directions—quasar is a long-lived gyroscope

• The high-speed blasts in our direction have their brightness amplified by special relativity—is this why they appear to start out one-sided?

We still can only theorize what makes the Central Engine tick?

Breaking News: Blasts from the heart of the Milky Way

• The 2.5 Million-solar mass black hole in the center of our galaxy is usually starved for fuel, but…

• It bursts in X-rays about 3 times per week

Just when you thought it was safe to go back to your home on Earth…

It spreads to our neighborhood…Will we be next??

Chandra (NASA’s third Great Observatory)

discovered the first flare serendipitously; then an intensive

followup campaign• Only the third of five orbits showed

comparably powerful bursts: they are so unpredictable that patience and luck are strongly required to study them

2000 October 26-27

Oct 27 05:42 UT45x, 4 hr

(Baganoff et al. 2001)

X-ray power from the center of our galaxy

Time

2002 May 22-23 – Orbit 1, Part 1

2002 May 24 – Orbit 1, Part 2

May 24 19:42 UT5x, 1.7 hr

2002 May 25-27 – Orbit 2

May 26 04:24 UT6x, 0.75 hr

May 24 19:42 UT5x, 1 hr

May 26 13:47 UT5x, 0.5 hr

2002 May 28-30 – Orbit 3May 28 15:36 UT

25x, 1 hrMay 29 18:33 UT

13x, 0.5 hr

May 29 06:03 UT12x, 1.5 hr

2002 June 3-4 – Orbit 5

Credit: NASA/MIT/F.K. Baganoff et al.

Chandra imaging may even show a weak X-ray jet left over from earlier activity

Plane of Milky WayAxis of outbursts?

Conclusions• We “need” strong enough gravity in the Universe to

make many giant black holes in galactic centers (as a by-product)

• Unique gravitational strength of a black hole is a tremendous accelerator, and a lot of the accelerated matter escapes the black hole vicinity at nearly c

• The most bizarre objects in the Universe may merely be ultra-extreme versions of what lurks in the centers of most galaxies

• Total energy (in many forms) produced by black holes in the history of the Universe may not be that much less than everything generated by fusion in stars

Faster-than-light jets?

• An illusion, produced when matter travels near the speed of light, close to our direction