Flipping of the tidal tails of the Ophiuchus stream due to the decelerating Galactic bar

Abstract

The Ophiuchus stellar stream presents a puzzle due to its complicated morphology, with a substructure perpendicular to the main track (spur), a broadened tail (fanning), and a shorter than expected angular extent given its old stellar population and short orbital period. The location of the stream approaches the Galactic center, implying a possible connection between its orbit and its unusual morphology. Here we demonstrate that the morphology of Ophiuchus can be attributed to its interaction with the decelerating Galactic bar, which leads to the flipping or transposition of its tidal tails. The short length of the stream is the result of stars stripped in the ancient past still remaining concentrated, and the spur, as well as the fanning, are composed of either leading or trailing tails built up of stars released at different time intervals. Our new spectroscopic data, obtained as part of the Southern Stellar Stream Spectroscopic Survey $(S^5)$, and modeling of Ophiuchus indicate that, in the presence of the bar, an initial leading tail can be redistributed to the trailing side and vice versa, and the morphology of a stream can be reshaped. This result confirms that the Galactic bar plays a vital role in reconstructing the orbital behavior of streams passing close to the central region of the Milky Way.

Accepted by ApJ, 20 pages, 12 figures, 1 machine readable table, 4 videos

References in corpus (26)

• Array Programming with NumPy
• Gaia Data Release 3: Summary of the content and survey properties
• Dynamical modelling of the Galactic bulge and bar: the Milky Way's bar pattern speed, stellar, and dark matter mass distribution
• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• The Dark Energy Survey Data Release 2
• "Skinny Milky Way, Please", says Sagittarius
• Charting the Galactic acceleration field I. A search for stellar streams with Gaia DR2 and EDR3 with follow-up from ESPaDOnS and UVES
• The Global Dynamical Atlas of the Milky Way mergers: Constraints from Gaia EDR3 based orbits of globular clusters, stellar streams and satellite galaxies
• A Synoptic Map of Halo Substructures from the Pan-STARRS1 3π Survey
• Measuring the Mass of the Large Magellanic Cloud with Stellar Streams Observed by $S^5$
• Forensics of Subhalo-Stream Encounters: The Three Phases of Gap Growth
• $S^5$: Probing the Milky Way and Magellanic Clouds potentials with the 6-D map of the Orphan-Chenab stream
• $S^5$: The Orbital and Chemical Properties of One Dozen Stellar Streams
• The DECam Local Volume Exploration Survey Data Release 2
• Broken into Pieces: ATLAS and Aliqa Uma as One Single Stream
• Gas Dynamics in the Galaxy: Total Mass Distribution and the Bar Pattern Speed
• Serendipitous Discovery of a Thin Stellar Stream near the Galactic Bulge in the Pan-STARRS1 3Pi Survey
• The stellar mass distribution of the Milky Way's bar: an analytic model
• The tidal remnant of an unusually metal-poor globular cluster
• Testing kinematic distances under a realistic Galactic potential
• Probability of forming gaps in the GD-1 stream by close encounters of globular clusters
• Dynamical friction and feedback on galactic bars in the general fast-slow regime
• A Larger Extent for the Ophiuchus Stream
• $S^5$: New insights from deep spectroscopic observations of the tidal tails of the globular clusters NGC 1261 and NGC 1904
• A New Cold Stream near the Southern Galactic Pole
• A Dwarf Galaxy Debris Stream Associated with Palomar 1 and the Anticenter Stream

Cited by in corpus (4)

• Bar-driven dispersal of Galactic substructure
• On the chaos induced by the Galactic bar on the orbits of nearby halo stars
• Chemodynamics of BoötesI with $S^5$: Revised Velocity Gradient, Dark Matter Density, and Galactic Chemical Evolution Constraints
• Epicyclic Density Variations in the Indus Stellar Stream