It is a fascinating time for the field of astronomy as recent discoveries have shed light on new galaxies, particularly one named Narrow-Line Seyfert 1 (NLS1) which has been found to emit gamma rays. This discovery was made by esteemed scientists of the Aryabhatta Research Institute of Observational Sciences (ARIES), in collaboration with other researchers.
Unravelling the Study
The research conducted by these scientists involved an extensive investigation of approximately 25,000 luminous Active Galactic Nuclei (AGN). These AGN are powerful, long-lived objects and steady sources of luminosity in the universe. The spectrum of their emission is diverse, ranging from the Ultra-Violet to x-ray and infrared bands.
To capture this data, the researchers employed the Sloan Digital Sky Survey (SDSS), a significant multi-spectral imaging and spectroscopic redshift survey that utilized a dedicated 2.5-m wide-angle optical telescope at the Apache Point Observatory in New Mexico, United States.
The Findings
The unique object discovered during this study emits high-energy gamma rays and is located at a high redshift, more than 1. Identified as a gamma-ray emitting NLS1 galaxy, this rare entity in space was formed when the Universe was merely 4.7 billion years old, compared to its current approximate age of 13.8 billion years.
Understanding Redshift
Redshift pertains to the displacement of spectral lines towards longer wavelengths in radiation emanating from distant galaxies and celestial objects. This measure offers crucial insights into an object’s spatial movement and allows astronomers to detect otherwise invisible planets and the movements of galaxies, as well as trace back to the origins of our universe.
Measuring Redshift
The prime method to measure redshift is through spectroscopy. It involves observing the spectrum formed by different elements and comparing it with the spectra of stars. A shift in the star’s spectra reflects its movement.
The Instrument Used
To capture these observations, scientists used the Japanese 8.2 m Subaru Telescope, one of the world’s largest ground-based telescopes located in Hawaii, USA. Its superior light-collecting capability allows it to capture even the faintest celestial objects.
The Significance of the Discovery
The detection of gamma-ray emissions challenges existing theories about the formation of relativistic jets. Understanding their formation is significant as these jets, produced by supermassive black holes at the center of some active galaxies, are believed to be the sources of cosmic rays, the fastest-travelling particles in the universe.
About ARIES
ARIES is a leading research institute specializing in observational astronomy and astrophysics and atmospheric sciences, situated in Nainital, Uttarakhand. Established in 1955, it has been consistently developing modern astrophysical research facilities.
What is a Galaxy?
A galaxy is a massive collection of gas, dust, billions of stars, and their solar systems, all held together by gravity. Our planet, Earth, is part of the Milky Way Galaxy, which also houses a supermassive black hole.
Black Holes Explained
A black hole is a point in space where matter is so compressed that it forms a strong gravitational field from which not even light can escape. Notably, there are two categories of black holes known so far.
Gamma Ray Astronomy
This is a specialized field dedicated to the study of astronomical objects and phenomena that emit gamma rays. Majority of the observations are conducted by high-altitude balloons or spacecraft, as Earth’s atmosphere blocks most gamma rays. This realm of astronomy presents unique opportunities to explore exotic objects and test theories that cannot be done in earth-bound laboratories.
