An all-sky view of the Orphan Stream

We use astrometry, broad-band photometry, and variability information from the Data Release 2 of ESA's Gaia mission (GDR2) to identify members of the Orphan Stream (OS) across the whole sky. The stream is traced above and below the celestial equator and in both Galactic hemispheres, thus increasing its visible length to ~210{deg} equivalent to ~150kpc in physical extent. Taking advantage of the large number of RR Lyrae stars in the OS, we extract accurate distances and proper motions across the entire stretch of the tidal debris studied. As delineated by the GDR2 RR Lyrae, the stream exhibits two prominent twists in its shape on the sky which are accompanied by changes in the tangential motion. We complement the RR Lyrae maps with those created using GDR2 Red Giants and the DECam Legacy Survey Main Sequence Turn-Off stars. The behaviour of the OS track on the sky is consistent across all three tracers employed. We detect a strong non-zero motion in the across-stream direction for a substantial portion of the stream. Such a misalignment between the debris track and the streaming velocity cannot be reproduced in a static gravitational potential and signals an interaction with a massive perturber.

Cone search capability for table J/MNRAS/485/4726/table15 (Subset of the likely Orphan RRL selected (Table 1 and 5))

Identifier
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/MNRAS/485/4726
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/485/4726
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/485/4726
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/MNRAS/485/4726
Provenance
Creator Koposov S.E.; Belokurov V.; Li T.S.; Mateu C.; Erkal D.; Grillmair C.J.,Hendel D.; Price-Whelan A.M.; Laporte C.F.P.; Hawkins K.; Sohn S.T.,del Pino A.; Evans N.W.; Slater C.T.; Kallivayalil N.; Navarro J.F.,(the Oats: Orphan Aspen Treasury Collaboration)
Publisher CDS
Publication Year 2022
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Galactic and extragalactic Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy