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The Geometry of the Sagittarius Stream from Pan-STARRS1 3π RR Lyrae

Hernitschek, Nina and Sesar, Branimir and Rix, Hans-Walter and Belokurov, Vasily and Martínez-Delgado, David and Martin, Nicolas F. and Kaiser, Nick and Hodapp, Klaus and Chambers, Kenneth C. and Wainscoat, Richard and Magnier, Eugene and Kudritzki, Rolf-Peter and Metcalfe, Nigel and Draper, Peter W. (2017) The Geometry of the Sagittarius Stream from Pan-STARRS1 3π RR Lyrae. Astrophysical Journal, 850 (1). Art. No. 96. ISSN 1538-4357. doi:10.3847/1538-4357/aa960c.

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We present a comprehensive and precise description of the Sagittarius (Sgr) stellar stream's 3D geometry as traced by its old stellar population. This analysis draws on the sample of ~44,000 RR Lyrae (RRab) stars from the Pan-STARRS1 (PS1) 3π survey, which is ~80% complete and ~90% pure within 80 kpc, and extends to ≳120 kpc with a distance precision of ~3%. A projection of RR Lyrae stars within |B|⊙ < 9° of the Sgr stream's orbital plane reveals the morphology of both the leading and the trailing arms at very high contrast across much of the sky. In particular, the map traces the stream near-contiguously through the distant apocenters. We fit a simple model for the mean distance and line-of-sight depth of the Sgr stream as a function of the orbital plane angle Λ⊙, along with a power-law background model for the field stars. This modeling results in estimates of the mean stream distance precise to ~1% and it resolves the stream's line-of-sight depth. These improved geometric constraints can serve as new constraints for dynamical stream models.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Hernitschek, Nina0000-0003-1681-0430
Sesar, Branimir0000-0002-0834-3978
Rix, Hans-Walter0000-0003-4996-9069
Belokurov, Vasily0000-0002-0038-9584
Martínez-Delgado, David0000-0003-3835-2231
Martin, Nicolas F.0000-0002-1349-202X
Kaiser, Nick0000-0001-6511-4306
Hodapp, Klaus0000-0003-0786-2140
Chambers, Kenneth C.0000-0001-6965-7789
Wainscoat, Richard0000-0002-1341-0952
Magnier, Eugene0000-0002-7965-2815
Metcalfe, Nigel0000-0001-9034-4402
Draper, Peter W.0000-0002-7204-9802
Additional Information:© 2017 The American Astronomical Society. Received 2017 August 11; revised 2017 October 23; accepted 2017 October 23; published 2017 November 21. N.H., B.S., and H.-W.R. acknowledge funding from the European Research Council under the European Union's Seventh Framework Programme (FP 7) ERC Grant Agreement n. [321035]. The Pan-STARRS1 Surveys (PS1) have been made possible through contributions of the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation under Grant No. AST-1238877, the University of Maryland, and Eotvos Lorand University (ELTE) and the Los Alamos National Laboratory.
Funding AgencyGrant Number
European Research Council (ERC)321035
Subject Keywords:galaxies: dwarf – stars: variables: RR Lyrae
Issue or Number:1
Record Number:CaltechAUTHORS:20171122-093810238
Persistent URL:
Official Citation:Nina Hernitschek et al 2017 ApJ 850 96
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:83429
Deposited By: Tony Diaz
Deposited On:22 Nov 2017 17:56
Last Modified:15 Nov 2021 19:58

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