Detection of Strong Epicyclic Density Spikes in the GD-1 Stellar Stream. An Absence of Evidence for the Influence of Dark Matter Subhalos?
| Autor: | Ibata, Rodrigo, Thomas, Guillaume, Famaey, Benoit, Malhan, Khyati, Martin, Nicolas, Monari, Giacomo |
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| Rok vydání: | 2020 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-4357/ab7303 |
| Popis: | The density variations in thin stellar streams may encode important information on the nature of the dark matter. For instance, if dark matter aggregates into massive sub-halos, these perturbers are expected to scatter stars out of dynamically cold stellar streams, possibly leading to detectable gaps in those structures. Here we re-examine the density variations in the GD-1 stream, using Gaia DR2 astrometry, Pan-STARRS photometry, together with high precision radial velocities measured with the CFHT/ESPaDOnS and VLT/UVES instruments and complemented with public radial velocity catalogs. We show that after correcting for projection effects, the density profile exhibits high contrast periodic peaks, separated by $2.64\pm0.18$ kpc. An N-body simulation is presented that reproduces this striking morphology with simple epicyclic motion in a smooth Galactic potential. We also discuss the reliability of measuring density variations using ground-based photometric surveys, and for the particular case of GD-1 we highlight some of the artifacts present in the Gaia DR2 catalog along its track. Massive dark subhalos do not appear to be required to explain the density clumping along GD-1. Comment: 18 pages, 14 figures, accepted for publication in ApJ (some typos fixed) |
| Databáze: | arXiv |
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