The Milky Way is pretty "recovered"

Having carried out new high -precision measurements of the speed of the sleeves of the Milky Way, the international group of astronomers made a conclusion according to which our galaxy not only rotates much faster than previously, but also weighs one and a half times more. Mark Reid (Mark Reid, www. Cfa.harvard.edu/~reid/ ) from Harvard-Smith-Astrophysical Center (Harvard-Smithsonian Center for Astrophysics) and his colleagues believe that the “increase” of the Military Way allows us to talk about it as an object, practically nothing inferior to Andromeda's nebula - the main “rival” in the local group of galaxies. “There is no longer any reason to perceive our galaxy as the younger sister of the Andromeda nebulae,” says Raid. Recall that most of the mass of the galaxy is not contained in the stars and interstellar gas, but in an inholent gall of dark matter. And the higher the total mass of all this education, the faster the stars move in their orbits around the Galactic Center.

Perhaps this new data will seem good news and reason for legitimate pride, however, a large mass in turn also means greater gravity, which significantly increases the probability of a clash with Andromeda’s nebula in the future and accelerates the arrival of this event (and also provokes not so catastrophic collisions with small nearby galaxies). However, be that as it may, and a couple of billions of years in stock has ...

Our own solar system is located about 28 thousand light years from the center of the Milky Way. As new observations show, we move around the orbit around this center at a speed of over 960 thousand km per hour, while according to previous estimates this value was up to 800 thousand km per hour. Measurements were made using a radio telescopes network (the basis of which is the American vlba system - www.vlba.nrao.edu) operating in radio interferometer mode with a super -long base. This network, which is maintained by the National Science Foundation, www.nsf.gov ), extends from the Hawaiian islands to New England and the Caribbean and has a record resolution that exceeds any other astronomical tool. VLBA can receive pictures, two orders of magnitude more detailed than those that are available to the Hubble space telescope (the working, however, in another - optical - range). With the help of VLBA, the International Scientific Group is engaged in the implementation of a long -term program to measure distances and evaluate the speeds of objects in the galaxy. Scientists reported on the results at the conference of the American Astronomical Society (American Astronomical Society, http://aas.org/meetings/aas213 ) in Long Beach (California).

First of all, scientists were interested in areas of active starship in galactic spiral sleeves. In these regions, processes generated by the interaction of space rays and gas molecules (for example, warm-up methanol vapors) lead to natural ma-granous radio radiation. Such radiation is recorded at certain frequencies corresponding to the energy transitions inside the molecule. This partly resembles the pumping mechanism in lasers, where light bundles are already involved in such processes. These sources, called astrophysical masters, serve as bright "hangers" for observing VLBA. Observing these regions in different periods - when the Earth is on the opposite sides of its periosolny orbit - astronomers can measure small, but completely distinguishable displacements of objects of objects against the background of even more distant sources.

“New observations of the Milky Way using VLBA allow high-precision direct measurements of distances and movements,” explains the member of the group of Karl Menten, www.mpifr-bonn. Mpg.de/kmenten/) from the German radio-antimony institute named after Max-institut Fur Radioastronomie). “These measurements use a completely traditional and simple triangulation method and do not depend on any assumptions based on the properties of the sources themselves (for example, do not depend on their brightness), unlike previous studies.” Astronomers found that the method of direct measurement of distances gives differences in the values ​​from previous measurements made by indirect methods. Sometimes these values ​​differ twice. In the regions where stars are formed, cosmic masks are hidden, noting the location of relatively dense spiral sleeves of the galaxy. The measurement of distances to these regions, therefore, allows you to make maps of galactic spiral structures. “These direct dimensions allow you to revise our understanding of structures and their movements in the galaxy,” Menten believes. And he explains: “Since we are inside this structure, it is very difficult for us to study the mutual arrangement of its elements. Indeed, we can simply look at other galaxies from the outside, observing their structure, but receiving a common photo of the entire Milky Way at the current stage is completely excluded. We must reconstruct its appearance through individual measurements and comparisons. ”

Adding to measurements of objects of objects against the background of distant galaxies information about the radial speeds of the studied sources,
Determined by measuring the Doppler shift in the frequency of Ma-grain radio radiation, astronomers can completely restore the nature of the movement of the sleeves in all three dimensions. Using this information, the raid and his colleagues found that most regions of starship, it turns out, should not be in circular orbits after other galactic objects; Instead, we are observing their slow motion, saying that they are moving in orbits elliptical, and not circular. Researchers associate all this with the fact that in theory it is called density waves. These waves are capable of, in particular, to “rake” gas on circular orbits, squeeze it in the form of a star and cause the transition of the resulting object to a new elliptical orbit. All this, according to researchers, contributes to the further manifestation and strengthening of spiral structures.

The raid group also faced other surprises. So, the measurement of distances to several regions in one of the spiral sleeves allowed them to calculate the angle under which this sleeve is located. These measurements, according to the raid, may indicate that our galaxy may have four, and not two spiral branches of gas and dust in which new stars are formed. At the same time, the latest studies conducted using the NASA Spitzer Spitzer space telescope (Spice Telescope) indicate that old stars live mainly in two old spiral sleeves. As a result, the question arises: why do the old stars do not fill all available sleeves? To correctly answer it, further measurements and a deeper analysis of the mechanisms of the work of galactic sleeves will be required.

Maxim Borisov

1. Milky Way A Swifter Spinner, More Massive, New Measurements Show
   www.nrao.edu/pr/2009/mwrotate
2. MILKY WAY BIGGER, FASTER THE PREVIOUSLY THUUGHT
   http://harvardscience.harvard.edu/foundations/articles/milky-way-bigger-faster-previous-though