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First Gaia Local Group Dynamics: Magellanic Clouds Proper Motion and Rotation
- Source :
- NASA Astrophysics Data System
- Publication Year :
- 2016
-
Abstract
- We use the Gaia data release 1 (DR1) to study the proper motion (PM) fields of the Large and Small Magellanic Clouds (LMC, SMC). This uses the Tycho-Gaia Astrometric Solution (TGAS) PMs for 29 Hipparcos stars in the LMC and 8 in the SMC. The LMC PM in the West and North directions is inferred to be $(\mu_W,\mu_N) = (-1.872 \pm 0.045, 0.224 \pm 0.054)$ mas/yr, and the SMC PM $(\mu_W,\mu_N) = (-0.874 \pm 0.066, -1.229 \pm 0.047)$ mas/yr. These results have similar accuracy and agree to within the uncertainties with existing Hubble Space Telescope (HST) PM measurements. Since TGAS uses different methods with different systematics, this provides an external validation of both data sets and their underlying approaches. Residual DR1 systematics may affect the TGAS results, but the HST agreement implies this must be below the random errors. Also in agreement with prior HST studies, the TGAS LMC PM field clearly shows the clockwise rotation of the disk, even though it takes the LMC disk in excess of $10^8$ years to complete one revolution. The implied rotation curve amplitude for young LMC stars is consistent with that inferred from line-of-sight (LOS) velocity measurements. Comparison of the PM and LOS rotation curves implies a kinematic LMC distance modulus $m-M = 18.54 \pm 0.39$, consistent but not yet competitive with photometric methods. These first results from Gaia on the topic of Local Group dynamics provide an indication of how its future data releases will revolutionize this field.<br />Comment: Accepted for publication in ApJ Letters. Minor modifications in response to referee suggestions
- Subjects :
- Physics
Line-of-sight
Proper motion
010308 nuclear & particles physics
Local Group
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
01 natural sciences
Astrophysics - Astrophysics of Galaxies
Stars
Distance modulus
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
Astrophysics::Earth and Planetary Astrophysics
Small Magellanic Cloud
010303 astronomy & astrophysics
Rotation (mathematics)
Astrophysics::Galaxy Astrophysics
Galaxy rotation curve
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- NASA Astrophysics Data System
- Accession number :
- edsair.doi.dedup.....69412fb092a858fa43764e3531b6773c