The discovery of Segue 2: a prototype of the population of satellites of satellites

By V. Belokurov, M. Walker, N. Evans II, G. Gilmore, M. Irwin, M. Mateo, Lucio Mayer, E. Olszewski, J. Bechtold, T. Cambridge and 4 more. 2009

178 citations recorded by the source corpus.

We announce the discovery of a new Milky Way satellite Segue 2 found in the data of the Sloan Extension for Galactic Understanding and Exploration (SEGUE). We followed this up with deeper imaging and spectroscopy on the Multiple Mirror Telescope (MMT). From this, we derive a luminosity of M v =− 2.5, a half-light radius of 34 pc and a systemic velocity of ∼− 40 km s −1 . Our data also provide evidence for a stream around Segue 2 at a similar heliocentric velocity, and the SEGUE data show that it is also present in neighbouring fields. We resolve the velocity dispersion of Segue 2 as 3.4 km s −1 and the possible stream as ∼ 7k m s −1 . This object shows points of comparison with other recent discoveries, Segue 1, Boo II and Coma. We speculate that all four objects may be representatives of a population of satellites of satellites – survivors of accretion events that destroyed their larger but less dense parents. They are likely to have formed at redshifts z> 10 and are good candidates for fossils of the reionization epoch.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/1de63fe2983dbc2b8c44cfcde3e85249db0b29e5

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

THE QUENCHING OF THE ULTRA-FAINT DWARF GALAXIES IN THE REIONIZATION ERA (2014, background): “Of the globular clusters with little extinction, it is the most metal-poor (Harris 1996), and it has served as a reference population in previous studies of UFDs (e.g., Belokurov et al. 2006, 2007, 2009, 2010; Okamoto et al. 2008, 2012; Sand et al. 2009, 2010, 2012).”
Milky Way Satellite Census. I. The Observational Selection Function for Milky Way Satellites in DES Y3 and Pan-STARRS DR1 (2019, methodology): “…of large digital sky surveys enabled the discovery of fainter systems using statistical matched-filter techniques (Willman et al. 2005a,b; Zucker et al. 2006a,b; Belokurov et al. 2006, 2007, 2008, 2009, 2010; Grillmair 2006, 2009; Sakamoto & Hasegawa 2006; Irwin et al. 2007; Walsh et al. 2007).”
A MegaCam Survey of Outer Halo Satellites. III. Photometric and Structural Parameters (2018, background): “Segue 2 With a total luminosity of just ∼ 500 L and a central surface brightness of µ0,V ∼ 28.5 mag arcsec−2, Segue 2 is one of the faintest and most diffuse of the ultra-faint satellites discovered in the SDSS (Belokurov et al. 2009).”
A COMPLETE SPECTROSCOPIC SURVEY OF THE MILKY WAY SATELLITE SEGUE 1: THE DARKEST GALAXY (2010, background): “…most of the faintest dwarfs such as Willman 1 (Willman et al. 2005), Boötes II (Walsh et al. 2007), Segue 1 (Belokurov et al. 2007a), and Segue 2 (Belokurov et al. 2009) remain relatively poorly characterized by observations; for example, the dynamical state of Willman 1 has still has not been…”
BIG FISH, LITTLE FISH: TWO NEW ULTRA-FAINT SATELLITES OF THE MILKY WAY (2010, background): “We have already presented the first result, the discovery of the Segue 2 satellite (Belokurov et al. 2009).”
One Law to Rule Them All: The Radial Acceleration Relation of Galaxies (2016, unknown): “…Jong et al. (2010), 32: Walker et al. (2009a), 33: Irwin et al. (2007), 34: de Jong et al. (2008), 35: Sand et al. (2012), 36: Simon et al. (2011), 37: Belokurov et al. (2009), 38: Kirby et al. (2013), 39: Bernard et al. (2009), 40: McConnachie (2012), 41: Fraternali et al. (2009), 42: Okamoto…”
Milky Way Satellite Census. II. Galaxy–Halo Connection Constraints Including the Impact of the Large Magellanic Cloud (2019, background): “…in particular, following the successes of the Sloan Digital Sky Survey (SDSS) in the early 2000s (Willman et al. 2005a,b; Zucker et al. 2006; Belokurov et al. 2006, 2007, 2008, 2009, 2010; Grillmair 2006, 2009; Sakamoto & Hasegawa 2006; Irwin et al. 2007; Walsh et al. 2007), the Dark Energy…”
MULTI-ELEMENT ABUNDANCE MEASUREMENTS FROM MEDIUM-RESOLUTION SPECTRA. III. METALLICITY DISTRIBUTIONS OF MILKY WAY DWARF SATELLITE GALAXIES (2010, background): “…MW dwarfs less luminous than Sagittarius except the least luminous objects (Willman 1, Willman et al. 2005; Segue 1, Belokurov et al. 2007; Segue 2, Belokurov et al. 2009; Boötes II, Walsh et al. 2007; Leo V, Belokurov et al. 2008; Pisces I, Watkins et al. 2009; and Pisces II and Segue 3,…”
The impact of dark matter cusps and cores on the satellite galaxy population around spiral galaxies (2010, background): “Among the known MW satellites Belokurov et al. (2009) identifies four possible candidates for being fossils of re-ionization: Segue I and II, Bootes II and Coma.”
Sweating the small stuff: simulating dwarf galaxies, ultra-faint dwarf galaxies, and their own tiny satellites (2015, background): “…et al. 2010), the faintest of which were all discovered by the Sloan Digital Sky Survey (SDSS) (Willman et al. 2005a,b; Grillmair 2006; Sakamoto & Hasegawa 2006; Irwin et al. 2007; Walsh, Jerjen & Willman 2007; Grillmair 2009; Zucker et al. 2006a,b; Belokurov et al. 2006, 2007, 2008, 2009, 2010).”
THE STAR FORMATION HISTORIES OF LOCAL GROUP DWARF GALAXIES. I. HUBBLE SPACE TELESCOPE/WIDE FIELD PLANETARY CAMERA 2 OBSERVATIONS (2014, background): “While the least luminous dSphs may be more susceptible to galaxy evolutionary mechanisms (e.g., tidal effects, stellar feedback, Belokurov et al. 2009; Kirby et al. 2013) and have had simpler chemical enrichment histories (e.g., Frebel & Bromm 2012), these effects may be a function of mass and…”
The Local Group on FIRE: dwarf galaxy populations across a suite of hydrodynamic simulations (2018, unknown): “(Belokurov et al. 2009) and DES (Drlica-Wagner et al. 2015).”
A UNIVERSAL MASS PROFILE FOR DWARF SPHEROIDAL GALAXIES? (2009, background): “…not only the bright Milky Way satellites but also the ultra-faint satellites discovered (e.g., Willman et al. 2005b; Zucker et al. 2006b,a; Belokurov et al. 2007) and observed spectroscopically (e.g., Martin et al. 2007; Simon & Geha 2007; Belokurov et al. 2009) during the past five years.”
DWARF GALAXY ANNIHILATION AND DECAY EMISSION PROFILES FOR DARK MATTER EXPERIMENTS (2014, methodology): “…dwarf galaxies have been discovered in recent years (Willman et al. 2005; Zucker et al. 2006b,a; Walsh et al. 2007; Belokurov et al. 2007, 2008; Belokurov et al. 2009, 2010) with the prospect of more discoveries from ongoing and future sky surveys like Pan-Starrs (Kaiser et al. 2002), the…”
The Masses of the Milky Way and Andromeda galaxies (2010, unknown): “…et al. (2007); 21, Belokurov et al. (2008); 22, Cioni et al. (2000); 23, Harris & Zaritsky (2006); 24, Ibata et al. (1997); 25, Kaluzny et al. (1995); 26, Queloz, Dubath & Pasquini (1995); 27, Geha et al. (2009); 28, Belokurov et al. (2009); 29, Walker et al. (2006b); 30, Zucker et al. (2006b).”
Gaia DR2 proper motions of dwarf galaxies within 420 kpc (2018, background): “We note that there is a stream at a similar distance as Segue 2 (Belokurov et al. 2009; Kirby et al. 2013), and that Massari & Helmi (2018) use of projected distance from the galaxy center as a criterion to start isolating targets is based on a simple cut.”
A KINEMATIC STUDY OF THE ANDROMEDA DWARF SPHEROIDAL SYSTEM (2013, methodology): “We plot the MW dSphs as red triangles (Martin et al. 2007; Kirby et al. 2008, 2011; Belokurov et al. 2009; Koch et al. 2009).”
CONSTRAINTS ON MACHO DARK MATTER FROM COMPACT STELLAR SYSTEMS IN ULTRA-FAINT DWARF GALAXIES (2016, unknown): “†† References abbreviated as: 1 (Martin et al. 2007); 2 (Martin et al. 2008); 3 (Simon et al. 2011); 4 (Belokurov et al. 2009); 5 (Bechtol et al. 2015); 6 (Koposov et al. 2015a); 7 (Koposov et al. 2015b); 8 (Laevens et al. 2015); 9 (Crnojević et al. 2016) * Geometric means of Koposov et al.…”
BEASTS OF THE SOUTHERN WILD: DISCOVERY OF NINE ULTRA FAINT SATELLITES IN THE VICINITY OF THE MAGELLANIC CLOUDS (2015, unknown): “In the case of the UFD Segue 2 for example, the group’s central object appears to have been destroyed and can now be detected only as tidal debris in the MW halo (Belokurov et al. 2009; Deason et al. 2014).”