college station much like quiet middle-aged baby boomers peacefully residing in some of the worlds largest cities families of some galaxies also have a hidden wild youth that they only now are revealing for the first time according to research by astronomers at texas a&m university in ongoing observations of one of the universes earliest most distant cluster of galaxies using nasas spitzer space telescope an international team of researchers led by texas a&ms dr kim-vy tran has discovered that a significant fraction of those ancient galaxies are still actively forming stars kim tran casey papovich tran an assistant professor in the texas a&m department of physics and astronomy and member of the george p and cynthia woods mitchell institute for fundamental physics and astronomy and her team have spent the past 4 months analyzing images taken from the multiband imaging photometer for spitzer (mips) essentially looking back in time nearly 10 billion years at a high red-shift cluster known as clg j02182-05102 mere months after first discovering the cluster and the fact that it is shockingly modern in its appearance and size despite being observed just 4 billion years after the big bang the texas a&m-led team was able to determine that the galaxy cluster produces hundreds to thousands of new stars every year a far higher birthrate than what is present in nearby galaxies what is particularly striking according to tran is the fact that the stellar birthrate is higher in the clusters center than at the clusters edges the exact opposite of what happens in our local portion of the universe where the cores of galaxy clusters are known to be galactic graveyards full of massive elliptical galaxies composed of old stars a well-established hallmark of galaxy evolution in action is how the fraction of star-forming galaxies decreases with increasing galaxy density explains tran lead author of the teams study which appears in the astrophysical journal letters in other words there are more star-forming galaxies in the field than in the crowded cores of galaxy clusters however in our cluster we find many galaxies with star-formation rates comparable to their cousins in the lower-density field environment exactly why this star power increases as galaxies become more crowded remains a mystery tran thinks the densely-populated surroundings could lead to galaxies triggering activity in one another or that all galaxies were extremely active when the universe was young the groups discovery holds potentially compelling implications that could ultimately reveal more about how such massive galaxies form observations of nearby galaxy clusters confirm that they are made of stars that are at least 8 to 10 billion years old which means that clg j02182-05102 is nearing the end of its hyperactive star-building period now that they have pinpointed the epoch when galaxy clusters are making the last of their stars astronomers can focus on understanding why massive assemblies of galaxies transition from very active to passive identifying how long it takes for galaxies in clusters to build up their stellar mass as well as the time at which they stop provides strong constraints for how these massive galaxies form our study shows that by looking farther into the distant universe we have revealed the missing link between the active galaxies and the quiescent behemoths that live in the local universe tran adds our discovery indicates that future studies of galaxy clusters in this red-shift range should be particularly fruitful for understanding how these massive galaxies form as a function of their environment trans team includes fellow texas a&m astronomer dr casey papovich who first identified the galaxy cluster clg j02182-05102 in may the collection of roughly 60 galaxies is observed just 4 billion years after the big bang making it the earliest cluster of galaxies ever detected however the team was struck not by its age but by its astoundingly modern appearance a huge red collection of galaxies typical in only local clusters the fact that trans team was able to see these active galaxies so far back in time (tran likens their find to discovering that her mild-mannered grandparent had lived a fast and furious youth) is only the preface to what they expect eventually to learn about these clusters tran will continue to lead an international collaboration with papovich and their postdoctoral researchers to examine these clusters more thoroughly and hopefully to understand why they are still so energetic we will analyze new observations scheduled to be taken with the hubble space telescope and herschel space telescope to study these galaxies more carefully to understand why they are so active tran adds we will also start looking at several more distant galaxy clusters to see if we find similar behavior the teams findings are detailed in their paper reversal of fortune: confirmation of an increasing star formation-density relation in a cluster at z=162 available online at http://iopscienceioporg/2041-8205/719/2/l126/ for or additional information on texas a&m astronomy visit http://astronomytamuedu atm contact: chris jarvis (979) 845-7246 or cjarvis@sciencetamuedu or dr kim-vy tran (979) 862-2747 or vy@physicstamuedu the post hidden star power revealed appeared first on texas a&m college of science