What is Radio Astronomy?

MIT Haystack Observatory This material was developed under a grant from the National Science Foundation

The Electromagnetic Spectrum • Spans a range of wavelengths • Visible is just a narrow range • Radiowaves span a large range - from under 1mm to several meters

Sources of Radio emission • Solar System - sun, planets • Milky way - star forming regions, old stars, supernova remnants • Extragalactic - quasars, radio jets • Molecules

Sun

OPTICAL RADIO XRAY

Saturn RADIO INFRARED OPTICAL ULTRAVIOLET

Orion Nebula: Stars are born… RADIO INFRARED OPTICAL XRAY

Crab Nebula: a star that died in 1054 RADIO OPTICAL XRAY

Cassiopeia A: a star that died in ~1700 RADIO INFRARED OPTICAL XRAY

Sagittarius A: Mystery Mass in Galaxy Center RADIO OPTICAL

Virgo A: Hidden Massive Black Hole shooting out a Jet RADIO OPTICAL

Molecules

What are molecules good for?

• Detections - newest one - “glycoaldehyde” (sugar) • Probes - measure temperature, density, chemistry • Kinematics - velocities - doppler effect

HC 3 N as a density probe in the Taurus Molecular Cloud (TMC-1)

CH 3 CCH as a temperature probe in TMC-1

Model of H 2 O maser emission around NGC4258

How do radio telescopes work?

What is Resolution?

Interferometry Getting better “resolution”

NRAO/AUI Compare the radio image on the right, made with the Haystack 37-m single dish telescope at a frequency of 43 GHz with the radio image above made with the 27 element Very Large Array.

VLBI images of SiO maser emission in Orion and a possible model

SiO Masers around a highly evolved star - R Cassiopeia

VLBI sequence of a supernova in M81

Magnetic Fields in Active Galactic Nuclei • The Blazar 1055+018 – Active Galactic Nuclei – 15 billion light years distant – AGN are 40 times more luminous and 10,000 times larger than the brightest “normal” galaxies – Displays a colossal jet of relativistic plasma – Powered by a supermassive, rotating black hole