First ground-based CCD proper motions for Fornax II: Final results

Details First ground-based CCD proper motions for Fornax II: Final results First ground-based CCD proper motions for Fornax II: Final results

2011-08-16

arxiv.org/abs/1108.3141v1

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

Accepted by AJ. 25 pages, 9 figures, 9 tables. Interesting conclusions...Enjoy!

Scientific paper

We present the first entirely ground-based astrometric determination of the proper motion for the Fornax Local Group Dwarf Spheroidal satellite galaxy of the Milky Way, using CCD data acquired with the ESO 3.5 m NTT telescope at La Silla Observatory in Chile. Our unweighted mean from five Quasar fields in the background of Fornax, used as fiducial reference points, leads to $\mu_\alpha \cos \delta=0.62 \pm 0.16$ $\masy$, and $\mu_\delta=-0.53 \pm 0.15$ $\masy$. A detailed comparison with all previous measurements of this quantity seems to imply that there is still no convincing convergence to a single value, perhaps indicating the existence of unnacounted systematic effects in (some of) these measurements. From all available proper motion and radial velocity measurements for Fornax, we compute Fornax's orbital parameters and their uncertainty using a realistic Galactic potential and a Monte Carlo simulation. Properties of the derived orbits are then compared to main star formation episodes in the history of Fornax. All published proper motion values imply that Fornax has recently (200-300 Myr ago) approached perigalacticon at a distance of $\sim$150 kpc. However, the derived period exhibits a large scatter, as does the apogalacticon. Our orbit, being the most energetic, implies a very large apogalactic distance of $\sim 950$ kpc. If this were the case, then Fornax would be a representative of an hypervelocity MW satellite in late infall.

Affiliated with

Also associated with

No associations

Rating

First ground-based CCD proper motions for Fornax II: Final results does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with First ground-based CCD proper motions for Fornax II: Final results, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and First ground-based CCD proper motions for Fornax II: Final results will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-194615