RRAT J1819-1458
Encyclopedia
RRAT J1819-1458 is a Milky Way neutron star
and the best studied of the class of rotating radio transient
s (RRATs) first discovered in 2006.
emission. It has a rotation period of 4.26 seconds and a slow-down rate which implies it has a dipole magnetic field
strength higher than all other RRATs. In fact its magnetic field is stronger than the quantum critical limit. Its pulses are the brightest of all the RRATs and of the original 11 sources it has the highest burst rate.
It has been observed at X-ray
wavelengths in observations using the Chandra and XMM Newton X-ray telescopes where an X-ray spectrum typical of thermal emission from a cooling neutron was observed. Modulation of the X-ray light at the 4.26 second rotation period is also observed indicating that there are hot spots on the surface of the star, i.e. the temperature distribution is not uniform.
RRAT J1819-1458 has been monitored since its discovery and has been observed to exhibit glitches
, a rotational irregularity seen in many young pulsar
s and magnetars.
Neutron star
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
and the best studied of the class of rotating radio transient
Rotating radio transient
Rotating radio transients are sources of short, moderately bright, radio pulses, which were first discovered in 2006. RRATs are thought to be pulsars, i.e. rotating magnetised neutron stars which emit more sporadically and/or with higher pulse-to-pulse variability than the bulk of the known pulsars...
s (RRATs) first discovered in 2006.
General characteristics
RRAT J1819-1458 exhibits sporadic pulses of radioRadio waves
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers. Like all other electromagnetic waves,...
emission. It has a rotation period of 4.26 seconds and a slow-down rate which implies it has a dipole magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
strength higher than all other RRATs. In fact its magnetic field is stronger than the quantum critical limit. Its pulses are the brightest of all the RRATs and of the original 11 sources it has the highest burst rate.
It has been observed at X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
wavelengths in observations using the Chandra and XMM Newton X-ray telescopes where an X-ray spectrum typical of thermal emission from a cooling neutron was observed. Modulation of the X-ray light at the 4.26 second rotation period is also observed indicating that there are hot spots on the surface of the star, i.e. the temperature distribution is not uniform.
RRAT J1819-1458 has been monitored since its discovery and has been observed to exhibit glitches
Glitch (astronomy)
A glitch is a sudden increase in the rotational frequency of a rotation-powered pulsar, which usually decreases steadily due to braking provided by the emission of radiation and high-energy particles. It is unknown whether or not they are related to the timing noise which all pulsars exhibit...
, a rotational irregularity seen in many young pulsar
Pulsar
A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name...
s and magnetars.