For the first time, astronomers took the pulse of a distant galaxy right at its heart. Galaxy Messier 87 is found 53 million light years away from Earth.
The enormous elliptical galaxy spans 120,000 light years in diameter and is kept under observation by the Hubble Space Telescope. While it may look a peaceful glimmering galaxy in the black swath of space, astronomers with the Harvard-Smithsonian Center for Astrophysics have discovered that right at the galaxy’s heart things aren’t as static as previously thought. Old stars, known as red stars are acting like the galaxy’s heartbeat. Their pulse or pulsating light offered the astronomers a unique view into the dynamics of the Messier 87 galaxy, as well as its age.
The research drew on the images captured by the Hubble Space Telescope in 2006 and spanning a period of three months. Subjected to rigorous analysis, the images of the red stars in the elliptical galaxy Messier 87 showed something spectacular. While previously unnoticed, the stars were observed to project a bright light that can distinguish them from the other stars in the galaxy, engulfing them in their light. The astronomer team decided to see if they could be detected even when their light can’t be separated from that of the unchanging stars in their vicinity.
By analyzing the Hubble Space Telescope images the astronomers took the pulse of a distant galaxy right at its heart. The research team found that 25 percent of the pixels in the images were constantly changing over time. Pieter van Dokkum, one of the researchers working on the study and chair of the Yale University Astronomy Department stated that typically galaxies are perceived as steady beacons lighting in the sky.
However, they are actually shimmering and pulsating thanks to these stars. This is the case of galaxy Messier 87. What makes the stars pulsate is their age. As they age, they swell up by swallowing surrounding matter. In their last phases of their life, the pulsating is even more intense, preceding their death. The intensity increases or decreases with every few hundred days passed. According to the Hubble Space Telescope images, the variation in intensity in time is at 270 days.
The stars’ pulsation is also indicative of Messier 87’s age. According to this study the Messier 87 is 10 billion years old.
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