The nearest large galaxy to our own has a halo that extend out for a million light - old age around it and almost half fashion to the Milky Way , The Hubble Telescopehas observed . The halo is six times as large as previously think , and more surprisingly , has a thousand times the awaited batch .
As the soft gas surrounding galaxies , anchor ring might not seem that important . But Dr Nicolas Lehner of the University of Notre Dame said , “ The properties of these gaseous gloriole see the rate at which stars form in galaxies . ” The uncovering that Andromeda ’s halo contains half the mass of that galaxy ’s stars , announced inThe Astrophysical Journal , suggest they are more important than we knew .
TheAndromeda Galaxy , also known as M31 , is the most similar fellow member of theLocal Group of galaxiesto the Milky Way in size , although it contains 2 - 5 times as many champion . As such it is frequently used as a model for our own galaxy , which can be hard to study from the inside .
Galactic halos are unmanageable to scrutinize in depth , since the natural gas is gloomy in the absence of stars to light it up . Lehner and his fellow worker look for quasars which were potentially partially blur by the glory . " As the light from the quasars travels toward Hubble , the anchor ring ’s gasolene will absorb some of that light and make the quasar seem a little dismal in just a very small wavelength mountain chain , " says co - author J Christopher Howk . The reduction in brightness seen at particular ultraviolet wavelengths is attributed to the halo gun .
At such great distances , it ’s not precisely clear whether interfering gas comes from Andromeda ’s halo or the surroundings of a smaller galaxy , or perhaps the Milky Way . However , the author say , “ We gift several arguments that gas … observed in these directions originates from M31 circumgalactic culture medium ( CGM ) . ” In particular , they show that the gas is moving at speed exchangeable to nanus galaxies that circle Andromeda , but very different from those expected if it was around other object . The anchor ring also appears to finish quite suddenly around a million idle - years from Andromeda .
The absorption characteristics of the annulus evoke that it is not only primeval atomic number 1 and He , but has been enriched with big elements . The authors propose that these element are the ware of supernova , expelled beyond the galaxyby the force of the explosion of the star that formed them .
The authors evidence that the further one get from Andromeda , the more heavily ionized the hydrogen component of the gas becomes .
Andromeda is seeable under sullen sky and is aroundsix times the diameter of the moon . However , if we could see the halo it would be capable of stretch out from the sensible horizon halfway to overhead .
If the Milky Way ’s halo is of similar size of it the two would almost touch , a trailer of the 24-hour interval when thetwo galaxies will mix . However , measuring the boundaries of our own halo is much harder .
