Among the observatories established by NASA, the Compton Gamma Ray Observatory holds a special place because of the unique discoveries it made during its golden age. Compton followed the Hubble into orbit as a great observatory to examine the events corresponding to the high energy light or the Gamma rays. The observations it made significantly helped humans to open a new dimension to the cosmos. Supernovae, the explosive deaths of massive stars; pulsars, the spinning corpses of supernova explosions; black holes, the collapse of stars; and quasars, bright central regions of faraway galaxies, are such discoveries.
The CGRO comprised of four instruments that served four different functions. They were the,
- Burst And Transient Source Experiment (BATSE),
- The Oriented Scintillation Spectrometer Experiment (OSSE)
- The Imaging Compton Telescope (COMPTEL)
- The Energetic Gamma Ray Experiment Telescope (EGRET).
Discovery of Gamma-Ray Bursts
Because satellites could not provide accurate information about Gamma-ray bursts, scientists were confused whether they occurred in the Milky Way or beyond our galaxy. The four instruments onboard the Compton examined these theories in detail. These instruments could cover an area of 20 keV to 30 GeV of radiation found in the galactic plane at once. The BATSE instrument was able to identify at least a single gamma-ray burst per day, identifying nearly over 2800 detections.
The images showed that a large number of gamma-ray bursts originate in faraway galaxies, not nearby in our Milky Way and that they must be energetic. These led to the implementation of the Fermi Gamma-ray Space Telescope and the Swift Gamma-Ray Burst Explorer in the later years that observed Gamma-Ray bursts in great detail. They identified that Gamma Ray bursts were occurring due to the exploding and merging of neutron stars creating black holes.
Discovery of a Young Supernova Remnant (SNR)
The COMPTEL was able to identify a young supernova remnant called Vela that is believed to have been seen to earth in the 14th century. It observed that some of the Gamma-ray bursts create an afterglow. Further observations revealed that when a large star uses fuel and explodes its substance, it emits more photons. The supernova remnant is the residue that can be seen as a flame after being ignited for thousands of years.
The All-Sky Map
The all-sky map produce by one of the instruments in the CGRO revealed the emission from interactions between cosmic rays and the interstellar gas along the plane of the Milky Way. This was done in the light of a radioactive isotope of Aluminum. With help of this map, astronomers were able to carry out several other findings.
Pulsing Radiation in Compton’s Map
Pulsars are born due to supernova explosions. They are rotating neutron stars, which we refer to as magnetars. The charged particles confined in the magnetic field of the neutron star produce a radiation beam. This, coupled with the rotation of the neutron star, emits a “pulsating” radiation signal.
The Galactic Center: Blazars and Anti-matter Clouds
These are a type of quasars that emit the majority of their electromagnetic energy in the 30 MeV to 30 GeV portion of the spectrum. The CGRO surveyed the galactic center and discovered a possible antimatter cloud above the center. It also discovered that when a particle collides with its anti-particle partner, it produces intense photons or gamma rays that cause them to destroy each other.
The significance of this observatory lies in the discoveries it did rather than the images it captured. Although Compton no longer roams the space in search of mystery, the part it did for humanity is undeniably worth it.
01. Featured Image: https://go.nasa.gov/2VowLhf
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