Radio Transients

1
Radio TransientsEVLA Deep Fields

• Joseph Lazio
• Naval Research Laboratory
• SKA Project Scientist

2
The Dynamic Radio Sky

• Sub-stellar objects
• Brown dwarfs
• Extrasolar planets?
• Microquasars
• Scintillation
• UHECRs
• EM counterparts to GW sources?
• ETI
• Exploding black holes
• ???

• Neutron stars
• Magnetars
• Giant pulses
• Short GRBs?
• GRBs (g-ray loud g-ray quiet?)
• Afterglows
• Prompt emission?

Amplitude
Frequency (MHz)
Time
Rotating Radio Transients (RRATS)
Pulsating Brown Dwarfs
Unknowns
3
Wide-field SKA Precursors
Karoo Array Telescope (meerKAT, ZA)

• Large-NumberSmall-Diameter Arrays
• Galaxy Assembly Evolution, Gravitational
  Physics, Dynamic Radio Sky,

• Field of view expansion
• Signal transmission
• Processing and data management

• Novel antenna construction methods
• Wide-band feeds

4
Staring Observations
GCRT J1746-2757
XTE J1748-288
GCRT J1742-3001
GCRT J1745-3009
Hyman et al.
Bower et al.

• Series of transients found by repeated
  observations of same field by VLA!

5
Low-Mass Stars and Brown Dwarfs

• Low-mass stars and brown dwarfs show a rich
  variety of phenomena
• Probably driven by magnetic fields
• Brown dwarf magnetosphere / emission mechanism
• Connection to pulsar magnetosphere?
• Largely unexplored 1 GHz
• Unavoidable!

TVLM 513-46546 (Hallinan et al.)
Optical survey telescopes
6
Dynamic Radio Sky and 21st Century Astrophysics

• Transient sources are necessarily compact
• Locations of explosive or dynamic events
• Probe fundamental physics and astrophysics
• Radio signals modified by, and are powerful
  probes of, intervening media
• Dispersion
• Scattering
• Faraday rotation
• Media include
• Interplanetary medium (IPM)
• Interstellar medium (ISM)
• Intergalactic medium (IGM)

EVLA
Optical survey telescopes
X- and g-rays
LIGO, LISA
7
Transients EVLA H I Deep Field

• Legacy programs long-lasting value to broad
  community (viz. Hubble Deep Field)
• H I Deep Field (and others!) should not preclude
  transients observations
• Angular resolution
• Cadence

Pulsating Brown Dwarfs
Unknowns