college station everyone has a backstory even our own milky way galaxy and much like social media the picture is not always as pretty as it appears on the current surface says texas a&m university astronomer casey papovich papovich notes that large disk galaxies like our own milky way were not always the well-ordered pinwheel-like spiral structures we see in the universe today on the contrary he and other international experts who specialize in galaxy formation and evolution believe that about 8-to-10 billion years ago progenitors of the milky way and similar disk/spiral galaxies were smaller and less organized yet highly active in their youth composite image of the molecular gas (indicated in red) superimposed on hubble space telescope images of the four young milky way-like galaxies studied by texas a&m astronomer casey papovich and his collaborators using alma these hubble images are much sharper than the images of the gas from alma therefore while the gas appears as a halo here papovich says it is more likely to be co-spatial with the starlight in the galaxies (credit: national radio astronomy observatory) in previous nasa and national science foundation-funded research papovich and his collaborators showed that these younger versions of such galaxies were churning out new stars faster than at any other point in their lifespans suggesting that they must be amazingly rich in star-forming material and now they have compelling evidence the galactic equivalent of a smoking gun using the national radio astronomy observatorys atacama large millimeter/submillimeter array (alma) a huge highly sophisticated radio telescope array situated at 16 500 feet altitude in the high desert of chile a papovich-led team of astronomers studied four very young versions of galaxies like the milky way that are 9 billion light-years distant meaning the team could see them as they looked approximately 9 billion years ago they discovered that each galaxy was incredibly rich in carbon monoxide a well-known tracer of molecular gas which is the fuel for star formation the teams findings are reported in a paper posted to arxiv and set to be published in the inaugural issue of nature astronomy in january we used alma to detect adolescent versions of the milky way and found that such galaxies do indeed have much higher amounts of molecular gas which would fuel rapid star formation said papovich lead author on the paper and a member of the george p and cynthia woods mitchell institute for fundamental physics and astronomy i liken these galaxies to an adolescent human who consumes prodigious amounts of food to fuel their own growth during their teenage years dr casey papovich in addition to papovich the research team also includes fellow texas a&m astronomers ryan quadri and kim-vy tran as well as astronomers from leiden observatory in holland swinburne university and macquarie university in australia the national optical astronomy observatory (noao) the university of texas at austin lyon observatory in france and the max plank institute for astronomy in germany though the relative abundance of star-forming gas is extreme in these galaxies papovich says they are not yet fully formed and rather small compared to the milky way as we see it today the new alma data indicate that the vast majority of the mass in these galaxies is in cold molecular gas rather than in stars a situation that papovich says is reversed at present in our milky way where the mass in stars outweighs that in gas by a factor of 10 to 1 these observations he notes are helping build a complete picture of how matter in milky-way-size galaxies evolved and how our own galaxy formed most stars today exist in galaxies like the milky way so by studying how galaxies like our own formed weve come to understand the most typical locations of stars in the universe said papovich a member since 2008 of the texas a&m department of physics and astronomy where he is a co-holder of the marsha l 69 and ralph f schilling 68 chair in experimental physics our current research shows that milky way-mass galaxies appear to accumulate most of their gas during their first few billion years of history at that stage they have most of the fuel they need to produce the stars they currently encompass in the present the presence of extensive gas reservoirs backs up the teams previous observations that provided the first tangible pictures showcasing the unprecedented life story of milky way galaxy evolution among other details their prior study revealed a stellar birth rate 30 times higher than it is in the milky way today roughly one per year compared to about 30 each year 95 billion years ago thanks to alma and other innovative instruments that allow us to peer 9 billion years into the past to analyze galaxies that are likely similar to the progenitor of our own milky way galaxy we can actually prove what our observations show papovich said papovich and his team recently have been awarded more highly competitive time with alma to study the temperature and density of the star-forming gas allowing them to measure and map its transitions and phases and ideally the related impacts within the galaxies dr kim-vy tran dr ryan quadri this will begin to tell us how these galaxies formed stars at such a rapid pace compared to conditions at present he said papovich quadri and tran are among roughly two dozen astronomers around the world who have spent years studying carefully selected distant galaxies similar in mass to the progenitor of our own milky way that were found in two deep-sky program surveys of the universe the cosmic assembly near-infrared deep extragalactic legacy survey (candels) and the fourstar galaxy evolution survey (zfourge) beyond alma the teams research has used observations from nasas hubble and spitzer space telescopes and the european space agencys herschel space observatory the hubble images from the candels survey also provided structural information about galaxy sizes and how they evolved far-infrared light observations from spitzer and herschel helped the astronomers trace the star-formation rate the teams paper large molecular gas reservoirs in ancestors of milky way-mass galaxies 9 billion years ago can be viewed online along with related images and captions to learn more about papovichs research visit https://physicstamuedu/directory/casey-papovich/ for more information about texas a&m astronomy go to http://mitchelltamuedu/research/astronomy/ this story contains excerpts from a national radio astronomy observatory brief authored by public information officer charles blue # # # # # # # # # # about research at texas a&m university: as one of the worlds leading research institutions texas a&m is at the forefront in making significant contributions to scholarship and discovery including that of science and technology research conducted at texas a&m represented annual expenditures of more than $8666 million in fiscal year 2015 ranking texas a&m in the top 20 of the national science foundations higher education research and development survey (2015) texas a&ms research creates new knowledge that provides basic fundamental and applied contributions resulting in many cases in economic benefits to the state nation and world to learn more visit http://researchtamuedu -atm- contact: shana k hutchins (979) 862-1237 or dr casey papovich (979) 862-2704 or papovich@physicstamuedu the post texas a&m-led study helps prove galaxy evolution theory appeared first on college of science share: