THE NEXT GENERATION VIRGO CLUSTER SURVEY. XIX. TOMOGRAPHY OF MILKY WAY SUBSTRUCTURES IN THE NGVS FOOTPRINT

• Published in: The Astrophysical Journal
• Main Authors: Lokhorst, Deborah, Starkenburg, Else, McConnachie, Alan W., Navarro, Julio F., Ferrarese, Laura, Cote, Patrick, Liu, Chengze, Peng, Eric W., Gwyn, Stephen D. J., Cuillandre, Jean-Charles, Guhathakurta, Puragra
• Other Authors: Lokhorst, D (reprint author), Univ Victoria, Dept Phys & Astron, Victoria, BC V8P 1A1, Canada., Univ Victoria, Dept Phys & Astron, Victoria, BC V8P 1A1, Canada., Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany., Natl Res Council Canada, Herzberg Astron & Astrophys, 5071 W Saanich Rd, Victoria, BC V9E 2E7, Canada., Shanghai Jiao Tong Univ, Ctr Astron & Astrophys, Dept Phys & Astron, Shanghai 200240, Peoples R China., Shanghai Jiao Tong Univ, Shanghai Key Lab Particle Phys & Cosmol, Shanghai 200240, Peoples R China., Peking Univ, Dept Astron, Beijing 100871, Peoples R China., Peking Univ, Kavli Inst Astron & Astrophys, Beijing 100871, Peoples R China., Univ Paris Diderot, Lab AIM Paris Saclay, PSL Res Univ, CEA,IRFU,SAP,CNRS,INSU,Observ Paris, F-91191 Gif Sur Yvette, France., Univ Calif Santa Cruz, Dept Astron & Astrophys, 1156 High St, Santa Cruz, CA 95064 USA., Canadian Inst Adv Res CIFAR, Toronto, ON, Canada.
• Format: Journal/Newspaper
• Language: English
• Published: ASTROPHYSICAL JOURNAL 2016
• Subjects: Galaxy: halo; Galaxy: stellar content; Galaxy: structure; Local Group; SAGITTARIUS DWARF GALAXY; DIGITAL SKY SURVEY; RR-LYRAE SURVEY; SURVEY COMMISSIONING DATA; HORIZONTAL-BRANCH STARS; ULTRA-COMPACT DWARFS; GALACTIC HALO; STELLAR STREAM; GLOBULAR-CLUSTERS; SURVEY VIEW; Milky Way; DML
• Online Access: https://hdl.handle.net/20.500.11897/438455; https://doi.org/10.3847/0004-637X/819/2/124

The Next Generation Virgo Cluster Survey (NGVS) is a deep u*giz survey targeting the Virgo Cluster of galaxies at 16.5 Mpc. This survey provides high -quality photometry over an similar to 100 deg(2) region straddling the constellations of Virgo and Coma Berenices. This sightline through the Milky Way is noteworthy in that it intersects two of the most prominent substructures in the Galactic halo: the Virgo overdensity (VOD) and Sagittarius stellar stream (close to its bifurcation point). In this paper, we use deep u*gi imaging from the NGVS to perform tomography of the VOD and Sagittarius stream using main -sequence turnoff (MSTO) stars as a halo tracer population. The VOD, whose centroid is known to lie at somewhat lower declinations (alpha similar to 190 degrees, delta - 5 degrees) than is covered by the NGVS, is nevertheless clearly detected in the NGVS footprint at distances between similar to 8 and 25 kpc. By contrast, the Sagittarius stream is found to slice directly across the NGVS field at distances between 25 and 40 kpc, with a density maximum at similar or equal to 35 kpc. No evidence is found for new substructures beyond the Sagittarius stream, at least out to a distance of similar to 90 kpc-the largest distance to which we can reliably trace the halo using MSTO stars. We find clear evidence for a distance gradient in the Sagittarius stream across the similar to 30 degrees of sky covered by the NGVS and its flanking fields. We compare our distance measurements along the stream with those predicted by leading stream models. Canadian Institute for Advanced Research (CIFAR) Global Scholars Academy; National Science Foundation [NSF PHY11-25915]; National Natural Science Foundation of China (NSFC) [11203017, 11125313]; French Agence Nationale de la Recherche (ANR) [ANR10-BLANC-0506-01]; Canadian Advanced Network for Astronomical Research (CAN-FAR); CANARIE; Canadian Space Agency SCI(E) ARTICLE [e-mail] 2 819