Related papers: Can a Satellite Galaxy Merger Explain the Active P…
We present first results from a spectroscopic survey of 2000 F/G stars 0.5--5kpc from the Galactic plane, obtained with the 2dF facility on the AAT. These data show the mean rotation velocity of the thick disk about the Galactic center a…
The merger history of the Galaxy has been traced back firmly to redshift 2 (10 Billion years ago). While there have been claims of the existence of at least one more significant merger before this time, supporting evidence has been indirect…
The last two years have seen widespread acceptance of the idea that the Milky Way halo was largely created in an early (8-10 Gyr ago) and massive ($> 10^{10} M_\odot$) merger. The roots of this idea pre-date the Gaia mission, but the…
The region bounded by the inner tens of light years at the center of the Milky Way contains five principal components that coexist within the central deep gravitational potential well. These constituents are a black hole candidate (Sgr~A*)…
The Center of the Milky Way emits radiation through all the electromagnetic spectrum due to the presence of several astrophysical phenomena. Various scientifical questions remain unsolved in the picture that emerge from observations, the…
Nuclear Star Clusters are observed at the center of many galaxies. In particular in the center of the Milky Way the Nuclear Star Cluster coexists with a cen- tral supermassive black hole. The origin of these clusters is still unknown; a…
Theoretical considerations and observational data support the idea that mergers were more frequent in the past. At high redshifts, violent interactions and mergers may be implicated in the origin of Lyman-break galaxies, sub-mm starbursts,…
Understanding our Galactic Center is easier with insights from nearby galactic nuclei. Both the star formation activity in nuclear gas disks, driven by bars and nuclear bars, and the fueling of low-luminosity AGN, followed by feedback of…
According to the standard cosmological scenario, the large galaxies that we observe today have reached their current mass via mergers with smaller galaxy satellites (Moore et al.1999). This hierarchical process is expected to take place on…
In the past decade high resolution measurements in the infrared employing adaptive optics imaging on 10m telescopes have allowed determining the three dimensional orbits stars within ten light hours of the compact radio source at the center…
In the center of the Milky Way, as well as in many other galaxies, a compact star cluster around a very massive black hole is observed. One of the possible explanations for the formation of such Nuclear Star Clusters is based on the…
Theoretical considerations and observational data support the idea that mergers were more frequent in the past. At redshifts z = 2 to 5, violent interactions and mergers may be implicated by observations of Lyman-break galaxies, sub-mm…
The GAIA satellite will observe the Galaxy and its closest satellites in great detail. This should allow (i) dating past events of dwarf galaxies merging or interacting with the Galaxy, and much improved orbital parameters of the nine dwarf…
The center of the Milky Way hosts a massive black hole. The observational evidence for its existence is overwhelming. The compact radio source Sgr A* has been associated with a black hole since its discovery. In the last decade,…
We revisit the idea that the Galactic center (GC) is the dominant source of Galactic cosmic rays (GCRs), based on a series of new observational evidence. A unified model is proposed to explain the new phenomena of GCRs and $\gamma$-rays…
Different types of observations, together with consistent and physical modelizations, suggest as realistic the hypothesis of enrichement of galactic nuclei by mean of massive globular clusters orbitally decayed and merged in the inner…
A massive black hole resides in the center of most, perhaps all galaxies. The one in the center of our home galaxy, the Milky Way, provides a uniquely accessible laboratory for studying in detail the connections and interactions between a…
The relics of disrupted satellite galaxies around the Milky Way and Andromeda have been found, but direct evidence of a satellite galaxy in the early stages of being disrupted has remained elusive. We have discovered a dwarf satellite…
Like most galaxies, the Milky Way harbors a supermassive black hole (SMBH) at its center, surrounded by a nuclear star cluster. In this dense star cluster, direct collisions can occur between stars before they evolve off the main-sequence.…
The standard cosmological model ($\Lambda$-CDM) predicts that galaxies are built through hierarchical assembly on cosmological timescales$^{1,2}$. The Milky Way, like other disc galaxies, underwent violent mergers and accretion of small…