An international squad led past times researchers from the IAC used information from the ESA satellite Gaia to mensurate the motility of 39 dwarf galaxies. This information gives information on the dynamics of these galaxies, their histories in addition to their interactions alongside the Milky Way.
 |
| Credit: Instituto de Astrofísica de Canarias |
These modest galaxies accept been the bailiwick of the written report of an international squad of astronomers led past times Tobias K. Fritz in addition to Giuseppina Battaglia, both researchers of the Instituto de Astrofísica de Canarias (IAC). Thanks to the information acquired past times the ESA Gaia infinite mission, which became available inwards a minute liberate inwards Apr 2018, the researchers accept been able to mensurate the on-sky motility of 39 dwarf galaxies, determining direction in addition to velocity.
Before the minute liberate of information from the Gaia satellite, it was non possible to perform such measurements for 29 of the galaxies analyzed past times the team. The researchers flora that many of them are moving inwards a plane known equally the vast polar structure. "It was already known that many of the to a greater extent than massive dwarf galaxies were flora inwards this plane, exactly at nowadays nosotros know that also several of the less massive dwarf galaxies mightiness belong to this structure," says Fritz, master copy writer of the scientific article .
Battaglia highlights that the source of the vast polar construction is notwithstanding non fully understood, exactly its characteristics seem to challenge cosmological models of galaxy formation. Also, the Large Magellanic Cloud is flora inwards this planar structure, which mightiness imply the 2 are connected.
By analyzing the information concerning the motions, the squad flora that several of the dwarf galaxies accept orbits that convey them to a greater extent than or less the inner regions of the Milky Way. The gravitational attraction that the Galaxy exerts on these galaxies tin give the axe endure compared to the activity of tides. It is probable that a few of the dwarf galaxies studied are perturbed past times these tides, which stretch them similar a stream.
"This could explicate observed properties of some of these objects, such equally Hercules in addition to Crater II," says Fritz.
On the other hand, novel questions arise. "Over the years, some galaxies accept been observed to accept peculiar characteristics that could accept been potentially due to tidal perturbations past times the Galaxy (e.g. Carina I)," says Battaglia. "However, their orbits create non seem to confirm this hypothesis. Perhaps nosotros should ask that encounters alongside other dwarf galaxies mightiness accept been the culprit."
The researchers flora that the bulk of the galaxies studied are to a greater extent than or less the pericenter of their range (the request closest to the Galaxy center). Nonetheless, basic physics explains that they should pass most of their fourth dimension to a greater extent than or less the apocenter of their range (the request farthest from the Galaxy center). "This suggests that in that place should endure many to a greater extent than dwarf galaxies that accept yet to endure discovered in addition to that are hiding at large distances from the Galaxy center," states Fritz.
Dwarf galaxies, equally good beingness interesting inwards their ain right, are i of the few tracers of nighttime affair that tin give the axe endure used inwards the most external parts of the Milky Way. It is idea that this variety of affair accounts for virtually fourscore per centum of the total bulk of the universe. However, it cannot endure observed directly, in addition to detection is difficult. The movements of celestial bodies such equally dwarf galaxies tin give the axe endure used to mensurate the total bulk of affair inside a volume. This is determined past times subtracting the bulk of those luminous objects that are detected to obtain an guess of the total of nighttime matter. From this data, the researchers could infer that the total of nighttime affair inwards the Galaxy is high, virtually 1.6 trillion solar masses.
The findings are published inwards Astronomy & Astrophysics.
Source: Instituto de Astrofísica de Canarias [November 13, 2018]
Sumber http://archaeologynewsnetwork.blogspot.com
Before the minute liberate of information from the Gaia satellite, it was non possible to perform such measurements for 29 of the galaxies analyzed past times the team. The researchers flora that many of them are moving inwards a plane known equally the vast polar structure. "It was already known that many of the to a greater extent than massive dwarf galaxies were flora inwards this plane, exactly at nowadays nosotros know that also several of the less massive dwarf galaxies mightiness belong to this structure," says Fritz, master copy writer of the scientific article .
Battaglia highlights that the source of the vast polar construction is notwithstanding non fully understood, exactly its characteristics seem to challenge cosmological models of galaxy formation. Also, the Large Magellanic Cloud is flora inwards this planar structure, which mightiness imply the 2 are connected.
By analyzing the information concerning the motions, the squad flora that several of the dwarf galaxies accept orbits that convey them to a greater extent than or less the inner regions of the Milky Way. The gravitational attraction that the Galaxy exerts on these galaxies tin give the axe endure compared to the activity of tides. It is probable that a few of the dwarf galaxies studied are perturbed past times these tides, which stretch them similar a stream.
"This could explicate observed properties of some of these objects, such equally Hercules in addition to Crater II," says Fritz.
On the other hand, novel questions arise. "Over the years, some galaxies accept been observed to accept peculiar characteristics that could accept been potentially due to tidal perturbations past times the Galaxy (e.g. Carina I)," says Battaglia. "However, their orbits create non seem to confirm this hypothesis. Perhaps nosotros should ask that encounters alongside other dwarf galaxies mightiness accept been the culprit."
The researchers flora that the bulk of the galaxies studied are to a greater extent than or less the pericenter of their range (the request closest to the Galaxy center). Nonetheless, basic physics explains that they should pass most of their fourth dimension to a greater extent than or less the apocenter of their range (the request farthest from the Galaxy center). "This suggests that in that place should endure many to a greater extent than dwarf galaxies that accept yet to endure discovered in addition to that are hiding at large distances from the Galaxy center," states Fritz.
Dwarf galaxies, equally good beingness interesting inwards their ain right, are i of the few tracers of nighttime affair that tin give the axe endure used inwards the most external parts of the Milky Way. It is idea that this variety of affair accounts for virtually fourscore per centum of the total bulk of the universe. However, it cannot endure observed directly, in addition to detection is difficult. The movements of celestial bodies such equally dwarf galaxies tin give the axe endure used to mensurate the total bulk of affair inside a volume. This is determined past times subtracting the bulk of those luminous objects that are detected to obtain an guess of the total of nighttime matter. From this data, the researchers could infer that the total of nighttime affair inwards the Galaxy is high, virtually 1.6 trillion solar masses.
The findings are published inwards Astronomy & Astrophysics.
Source: Instituto de Astrofísica de Canarias [November 13, 2018]
Sumber http://archaeologynewsnetwork.blogspot.com
Buat lebih berguna, kongsi:
