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ESO / WFI; MPIfR / ESO / APEX / A.Weiss et al. NASA / CXC / CfA / R.Kraft
Image of Centaurus-A composed of images of three instruments operating at different wavelengths
Researchers of the Institute of Astrophysics and Space Science new discoveries that allow a better understanding of the nature and formation of the nucleus of spiral galaxies, such as the Milky Way, "long-standing riddle of extragalactic astronomy".
"Current knowledge has shown the existence of two types of star bulge found in the nucleus of most spiral galaxies: classical bulges and pseudo-bulges," Iris Breda ] one of the persons responsible for the study, told Lusa Polychronis Papaderos
According to the commonly accepted theory, mentioned by the scientist, the classical bulges were formed before the disc and are ancient star compounds, about ten billion years, while [1] 9459009] the pseudo globes are formed very slowly from the disc, along the l 39; evolution of the galaxy itself
These two scenarios, according to the IA, imply that classical bulges and pseudo-bulbs have radically different properties. "However, despite numerous studies conducted in recent years, " this contrast Marked has never been observed "notes the information note.
The results of this work from AI, published last month in the scientific journal Astronomy & Astrophysics reveal "solid evidence" that the two different types of bulges "do not result from process distinct ", contrary to the theory of training that has prevailed to date
Research Gate
Iris" Breda is a researcher in the Department of Physics and Astronomy of the Faculty of Sciences of the University of Porto [19659010"Byestimatingthepropertiesofaveryrepresentativesampleofspiralgalaxiesthetheorystudieduptothispointindicatedthatweshouldfindpropertiesthataggregateintotwocompletelydifferenttypes"saidIrisBredaalsoresearcherattheFacultyofSciencesoftheUniversityofPorto(1965-19005)theteamconcludedthat"itwasaclearandsignificantlystrongcontinuityinoneofthepropertiesmeasuredinthebulges"which"stronglycontradictsthemodelofthetwodistinctdrivingscenarios""
" The evolution of the bulge is influenced by a mixture of fast and slow processes whose importance is governed by the mass and density of each galaxy ", explains the scientist [19659005Thefindingsdemonstratethat"theformationtimeofthebulgeisinverselyproportionaltothetotalmassofthegalaxy:inmassivegalaxiesnucleusformation occurs within the first four billion years while in the lower mass formation continues at a slow pace, "explains Iris Breda
. To obtain these results, the group analyzed 135 galaxies which equates to about half a million spectra, in order to have sufficient resolution to verify
The team used computational tools and an instrument developed in the framework of the Spanish project CALIFA, which allows the simultaneous recording of thousands of spectra per galaxy, thus producing a three-dimensional view of the stars and the ionized gas of each galaxy, adds the declaration.
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