Star Shell Found Floating Around Quasar

NASA's Hubble Space Telescope has captured new images of a bright quasar known as MC2 1635+119 and, around the quasar, there can be seen broken bits of past stars called star shells.

Quasars are radio wave emissions from super massive black holes at the heart of red-shifting (moving away) old galaxies. The star shells, which sparkle like stars, are out-ward moving away from the galaxy's center. The speculation is that there was a massive collision between the elliptical quasar galaxy and another galaxy. During the collision, the other galaxy was what the scientists call shredded by tidal forces, which resulted in a trail of star shells and other debris traveling away from the galaxy's center like a ripple in water. There are five star shells and the furthest one is 40,000 light-years away from the quasar center of the elliptical galaxy.

Quasars were first discovered 50 years ago and it has been speculated that an inflowing of gas from some as yet unidentified source rushes into the black hole and generates the quasar emissions, feeding it as it were. Analysis of the Hubble images shows that the past collision is funneling tremendous quantities of gas into the galaxy's black hole. This finding confirms the speculation that quasars are fed some unidentified fuel and it identifies what produces this fuel in the quasars MC2 1635+119. This inflow of gas from the collision is the source of the quasar's energy.

Gabriela Canalizo of the University of California in Riverside takes it a step further and states: "This observation of broken bits, star shells, is providing more evidence that mergers [collisions] are crucial for triggering quasars."

Since the quasar is red-shifting, the galaxy around it is very distant and very old. Canalizo and the research team ran computer simulations to try to determine the eras during which the collision and eventual merger occurred. The computer model estimated that the collision occurred 1.7 billion years ago. After the initial collision, it took over a million years for the merger to be complete. During that epoch, myriads new stars were born in the colliding gasses. The stars ages were determined by using a spectroscope that showed that many of the stars were 1.4 billion years old. That age is consistent with the computer model simulation that puts the encounter between the two galaxies at around 1.7 billion years ago.

"We want to know whether most quasars at current epochs begin their lives as mergers, or whether they simply occur in old ellipticals to which nothing very interesting has happened recently," Canalizo said.

"Hubble Spies Shells of Sparkling Stars Around Quasar," NASA's Hubble Space Telescope.