Exploring Halo Substructure with Giant Stars. XI. The Tidal Tails of the Carina Dwarf Spheroidal Galaxy and the Discovery of Magellanic Cloud Stars in the Carina Foreground

By R. Muñoz, S. Majewski, S. Zaggia, W. Kunkel, P. Frinchaboy, D. Nidever, D. Crnojević, R. Patterson, J. Crane, K. Johnston and 3 more. 2006

143 citations recorded by the source corpus.

A new large-area Washington M, T2+DDO51 filter survey of more than 10 deg2 around the Carina dSph galaxy reveals a spectroscopically confirmed power-law radial density "break" population of Carina giant stars extending several degrees beyond the central King profile. Magellan telescope MIKE spectroscopy establishes the existence of Carina stars to at least 4.5 times its central King limiting radius, rlim, and primarily along Carina's major axis. To keep these stars bound to the dSph would require a global Carina mass-to-light ratio of M/L ≥ 6300 (M/L)☉. The MIKE velocities, supplemented with ~950 additional Carina field velocities from archived VLT+GIRAFFE spectra with r ≲ rlim, demonstrate a nearly constant Carina velocity dispersion (σv) to just beyond r = rlim and both a rising σv and a velocity shear at still larger radii. Together, the observational evidence suggests that the discovered extended Carina population represents tidal debris from the dSph. Of 65 giant candidates at large angular radii from the Carina center for which MIKE spectra have been obtained, 94% are associated with either Carina or a second, newly discovered diffuse, but strongly radial velocity-coherent (σv = 9.8 km s-1), foreground halo system. The 15 stars in this second, retrograde velocity population have (1) a mean metallicity ~1 dex higher than that of Carina and (2) colors and magnitudes consistent with the red clump of the LMC. Additional spectroscopy of giant star candidates in fields linking Carina and the LMC shows a smooth velocity gradient between the LMC and the retrograde Carina moving group. We conclude that we have found Magellanic stars almost twice as far (22°) from the LMC center than previously known.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/16923b73cae97ba1a9c666797894cab6a18fcbf5

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In Astronomy and Astrophysics

1. James S. Bullock
2. L. Strigari
3. M. Walker
4. Justin I. Read
5. M. Boylan-Kolchin
6. A. Helmi
7. N. Evans II
8. Pavel Kroupa

In Instrumentation

1. James S. Bullock
2. M. Walker
3. L. Strigari
4. Justin I. Read
5. A. Helmi
6. M. Boylan-Kolchin
7. N. Evans II
8. J. Peñarrubia

Citations in the corpus

• THIRD-EPOCH MAGELLANIC CLOUD PROPER MOTIONS. I. HUBBLE SPACE TELESCOPE/WFC3 DATA AND ORBIT IMPLICATIONS (2013, background): “Muñoz et al. (2006) have claimed a detection of LMC stars out to 20 kpc.”
• The Cold Dark Matter Halos of Local Group Dwarf Spheroidals (2007, background): “Much of this work is based on detecting stars associated with a dwarf beyond the King “tidal radius”, or on the interpretation of “breaks” in the surface density profile in the outer regions of a dwarf (e.g. Ursa Minor, Mart́ınezDelgado et al. 2001, Carina, Majewski et al. 2005).”
• The Velocity Dispersion Profile of the Remote Dwarf Spheroidal Galaxy Leo I: A Tidal Hit and Run? (2007, background): “It has long been discussed as a system with an extended pseudostream of stars (Majewski et al. 2000;Muñoz et al. 2006), and we may have already detected a break radius in its kinematics.”
• STELLAR VELOCITIES IN THE CARINA, FORNAX, SCULPTOR, AND SEXTANS dSph GALAXIES: DATA FROM THE MAGELLAN/MMFS SURVEY (2008, methodology): “The MMFS sample more than doubles the number of velocity measurements for dSph stars, dating from Aaronson’s (1983) initial kinematic study to the most recent published data from surveys using Keck and the VLT (Muñoz et al. 2006; Koch et al. 2006, 2007b, 2007a; Battaglia et al. 2006; Battaglia et a”
• Is the SMC Bound to the LMC? The Hubble Space Telescope Proper Motion of the SMC (2006, background): “While there is some evidence for tidally strippedMagellanic stars far (22 ) from the LMC center and in the direction of the Carina dwarf (Muñoz et al. 2006), no stars have yet been associated with the Magellanic Stream itself.”
• The Observed Properties of Dark Matter on Small Spatial Scales (2007, background): “Central velocity dispersions have been derived for several of the newly discovered extremely low luminosity dSph satellites of both the Milky Way andM31 (Kleyna et al. 2005; Ibata et al. 2006;Muñoz et al. 2006a).”
• Velocity Dispersion Profiles of Seven Dwarf Spheroidal Galaxies (2007, background): “Recent velocity measurements for several hundred stars per dSph (Kleyna et al. 2002, 2003, 2004; Muñoz et al. 2005, 2006; Walker et al. 2006a,b; Simon & Geha 2007) demonstrate that dSph velocity dispersions remain approximately flat with radius.”
• A COMPLETE SPECTROSCOPIC SURVEY OF THE MILKY WAY SATELLITE SEGUE 1: THE DARKEST GALAXY (2010, background): “…Mart́ınez-Delgado et al. 2001; Palma et al. 2003; Walcher et al. 2003; Wilkinson et al. 2004; Mashchenko, Couchman, & Sills 2005; Westfall et al. 2006; Muñoz et al. 2006; Sohn et al. 2007; Komiyama et al. 2007; Smolčić et al. 2007), but there is still no consensus regarding their physical…”
• The Origin of the Magellanic Stream and Its Leading Arm (2007, background): “Another possibility is that the LMC is actually much larger than previously thought (exceeding even the newly suggested limit in Muñoz et al. 2006) and the MS gas is escaping the tidal radius of the LMC at LMS ≈ −40◦.”
• A MegaCam Survey of Outer Halo Satellites. III. Photometric and Structural Parameters (2018, methodology): “Our number density profile does not show the previously reported “break" at ∼ 20′ (Majewski et al. 2000, 2005; Muñoz et al. 2006a), and is well fitted over its full extent by a Sérsic profile with ns = 0.84± 0.02.”
• Redefining the Missing Satellites Problem (2007, methodology): “We use the following data sets: Wilkinson et al. (2004); Munoz et al. (2005, 2006); Westfall et al. (2006); Walker et al. (2005, 2006); Sohn et al. (2006); Siegal et al. in preparation.”
• A UNIVERSAL MASS PROFILE FOR DWARF SPHEROIDAL GALAXIES? (2009, background): “Among the remaining dSphs in our sample, there exists kinematic evidence of tidal streaming motion in the outer parts of Carina (Muñoz et al. 2006) and Leo I (Sohn et al. 2007; Mateo et al. 2008).”
• THE SAGITTARIUS DWARF GALAXY: A MODEL FOR EVOLUTION IN A TRIAXIAL MILKY WAY HALO (2010, background): “…by the present day (e.g., Font et al. 2006), the metal-poor halo stars may simply have originated in the dSphs with which we are familiar, and in which few traces of the originally sizeable metal-poor populations now remain (e.g., Majewski et al. 2002; Muñoz et al. 2006; Chou et al. 2009).”
• A METHOD FOR MEASURING (SLOPES OF) THE MASS PROFILES OF DWARF SPHEROIDAL GALAXIES (2011, methodology): “…Bullock, J., Kaplinghat, M., & Trainor, R. 2010, ApJ, 721, 1142 Moore, B. 1994, Nature, 370, 629 Moore, B., Governato, F., Quinn, T., Stadel, J., & Lake, G. 1998, ApJ, 499, L5+ Muñoz et al. 2006, ApJ, 649, 201 Navarro, J. F., Eke, V. R., & Frenk, C. S. 1996, MNRAS, 283, L72 Navarro, Frenk & White.”
• The Kinematic Status and Mass Content of the Sculptor Dwarf Spheroidal Galaxy (2008, background): “…references therein); their kinematic status is generally believed to be undisturbed by interactions with the Milky Way (MW), with the exception of Carina (see Muñoz et al. 2006, and references therein), Boötes (e.g., Belokurov et al. 2006), and perhaps Ursa Minor (e.g., Bellazzini et al. 2002).”
• The stellar mass-halo mass relation of isolated field dwarfs : a critical test of ΛCDM at the edge of galaxy formation (2016, methodology): “This is derived by directly fitting N -body simulations of Carina tidally disrupting in the halo of the Milky Way to data for the positions and velocities of ‘extra-tidal’ stars reported in Muñoz et al. (2006).”
• Gaia DR2 proper motions of dwarf galaxies within 420 kpc (2018, background): “…in Carina can be considered as robust as they have been detected in multiple studies in the literature adopting different methodologies (see e.g. Muñoz et al. 2006; Battaglia et al. 2012; McMonigal et al. 2014, and references in); their presence might then suggest a preference for a heavy MW DM…”