Fast Radio Burst

Why in the News?

Astronomers have detected a mysterious, repeating fast radio burst emanating from a dwarf galaxy located 3 billion light-years away.

Key Points:

About Fast Radio Burst

• FRBs are high-energy phenomena, emitting electromagnetic energy in the form of bursts of radio pulses

• These last for an interval ranging from a mere fraction of a millisecond to a few milliseconds

• In each pulse, the source can emit as much energy as the sun does in a month

• FRBs are triggered by explosive events in the universe, such as a supernova or the collision of two compact objects like a neutron star and a black hole

• Such bursts typically occur as a transient flash only once, never to be seen again

• FRBs were first discovered in 2007 and there are still many gaps in information regarding them

Possible Origin:

• Many theories have suggested that FRBs are caused by neutron stars, that are the corpses of stars which died in explosions called supernovas

• The latest studies, published in a recent edition of the journal Nature have now confirmed that FRBs are in fact generated by a rare type of neutron star known as a ‘magnetar’

• A defining property of these bursts is their dispersion: 

  • The bursts produce a spectrum of radio waves, and as the waves travel through matter, they spread out – or disperse – with bursts at higher radio frequencies arriving at telescopes earlier than those at lower frequencies

Magnetars:

• A magnetar is a rare compact type of neutron star

• They are highly dense and have high rotation speeds i.e. 0.3 to 12.0 seconds

• Magnetars are formed when massive stars with masses around 10-25 times the mass of the Sun – collapse and shrink to form very compact objects called neutron stars

• A subset of these neutron stars are called magnetars which possess intense magnetic fields

• Magnetars have high magnetic fields in the range of 1015 gauss and they emit energy in the range given by luminosities of 1037– 1040 joules per second

• They emit violent flares which not only help us understand the physics of magnetars but are also helpful in understanding fast radio bursts

Pulsars & FRBs:

• FRBs are most likely bright analogs of pulsars, which are spinning neutron stars with strong magnetic fields

• The duration and radio frequency of FRBs is similar to the flashes from pulsars, but they are intrinsically billions times brighter

• As a result, we can see them from the edge of the Universe. Pulsars, on the other hand, are detectable only within the Milky Way galaxy

Significance:  

•  The unique properties of fast radio bursts and their host galaxies – combined with recent technological advancements like the CHIME telescope – have given researchers hope that these phenomena can be used to answer some long-standing questions about the universe