The Radio Sky Chris Salter NAIC/Arecibo Observatory
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