English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present 3D kinematic observations of stars within the central 0.5 pc ofthe Milky Way nuclear star cluster using adaptive optics imaging andspectroscopy from the Keck telescopes. Recent observations have shown that thecluster has a shallower surface density profile than expected for a dynamicallyrelaxed cusp, leading to important implications for its formation andevolution. However, the true three dimensional profile of the cluster isunknown due to the difficulty in de-projecting the stellar number counts. Here,we use spherical Jeans modeling of individual proper motions and radialvelocities to constrain for the first time, the de-projected spatial densityprofile, cluster velocity anisotropy, black hole mass ($M_\mathrm{BH}$), anddistance to the Galactic center ($R_0$) simultaneously. We find that the innerstellar density profile of the late-type stars, $\rho(r)\propto r^{-\gamma}$ tohave a power law slope $\gamma=0.05_{-0.60}^{+0.29}$, much more shallow thanthe frequently assumed Bahcall $\&$ Wolf slope of $\gamma=7/4$. The measuredslope will significantly affect dynamical predictions involving the cluster,such as the dynamical friction time scale. The cluster core must be larger than0.5 pc, which disfavors some scenarios for its origin. Our measurement of$M_\mathrm{BH}=5.76_{-1.26}^{+1.76}\times10^6$ $M_\odot$ and$R_0=8.92_{-0.55}^{+0.58}$ kpc is consistent with that derived from stellarorbits within 1$^{\prime\prime}$ of Sgr A*. When combined with the orbit ofS0-2, the uncertainty on $R_0$ is reduced by 30% ($8.46_{-0.38}^{+0.42}$ kpc).We suggest that the MW NSC can be used in the future in combination withstellar orbits to significantly improve constraints on $R_0$.

3D stellar kinematics at the Galactic center: measuring the nuclear star cluster spatial density profile, black hole mass, and distance