The Radio Sky

Chris Salter

NAIC/Arecibo Observatory

“Suppose that our eyes responded to radio waves, rather than light, how different would the Night Sky appear?”

I find a very steady hiss type static of unknown originWhose direction of arrival goes almost around the Compass in 24 hours Karl Jansky -- 1932

Our Radio Our Radio EyesEyes

Angular Resolution = Angular Resolution = /Diameter/Diameter

GBT 100-m telescope (WV, USA)

Effelsberg 100-m telescope (FRG)

Arecibo 305-m telescope (Puerto Rico)

IRAM 30-m mm-wave telescope (Spain)Ooty Radio Telescope 530 30 m (India)

Emission MechanismsEmission MechanismsThermal emission is unpolarized.

a) Solid body; e.g. planet, you, me.b) Free-free emission from a hot ionized gas.c) Dust particles.d) Thermal spectral line emission.

Recombination Lines near 5 GHz

Non-thermal emission is generally polarized.

a) Synchrotron Emission due to helical trajectories of ultra-relativistic electrons crossing interstellar magnetic fields. b) Maser-like line emission, e.g. OH, H

2O, CH

3OH

and SiO.

Water maser line

The Whole Radio Sky (408 MHz – λ73 cm)The Whole Radio Sky (408 MHz – λ73 cm)

Galactic Center

North Polar Spur

SMC &LMC

Cas-A

Cen-ACyg-X; (the local Main St.)

Synchrotron EmissionSynchrotron Emission

Cosmic Micwave Background (WMAP; 90 GHz Cosmic Micwave Background (WMAP; 90 GHz – λ3 mm– λ3 mm))

The Celestial Neutral Hydrogen (HI) Emission

HI Continuum

The Radio Solar SystemThe Radio Solar System

Saturn -- VLA

Moon -- (IRAM 30-m telescope; 230 GHz)

Jupiter -- VLA

As seen by a“Passive”

Radio Astronomer

JupiterJupiter

2.3 GHz (13 cm) 1.4 GHz (22 cm)

(Continuum spectrum, including decametric bursts)

True Radio StarsTrue Radio Stars

X-ray BinaryX-ray Binary

SS433

Radio Image (Artist’s Impression)

Radio Light Curve

X-Ray Image

Supernova RemnantsSupernova RemnantsCas A – about 1680 AD Crab Nebula – 1054 AD

(AD 1572)

W 50

Supernova 1987A (Optical)

PulsarsPulsarsPSR 0329+54

Discovery of Pulsars (1967) The Double Pulsars(Artist’s Impression)

About 1600 pulsars are currently known.

Pulsar periodicities are between 0.0014 and 8.5 sec.

All pulsars are slowing down.

HII Regions – The Youngest StarsHII Regions – The Youngest Stars Orion Nebula: Optical

Radio Continuum

Mm-wave Line SpectrumFree-free emission

When a molecule changes its rotation, vibration or bending state to one of lower energy, it radiates a photon. If the change of energy is very small, the photon is a radio photon.

rotation

Spiral GalaxiesSpiral GalaxiesM31 -- Optical

M31 -- Radio Continuum

M31 -- HI

I

Elliptical GalaxiesElliptical Galaxies

Centaurus A (Optical)

Cygnus A -- (Radio; FR II)

M 87 -- Optical

Centaurus A (High-resolution Radio; FR I)

Radio Source Image GalleryRadio Source Image Gallery3C31 (Source in galaxy group)

3C296 (Double-jet radio galaxy)

NGC 1265 (Narrow-angled tail cluster galaxy) 3C175 (Double-lobed quasar)

Fornax A (Nearby radio galaxy)J0204+1514 (Compact Quasar)

The Canonical Model of AGNsThe Canonical Model of AGNs

Optical Radio

MODEL

Superluminal Motion & Gravitational LensingSuperluminal Motion & Gravitational Lensing

4C 05.51

CLASS B1359+154