BEASTS OF THE SOUTHERN WILD: DISCOVERY OF NINE ULTRA FAINT SATELLITES IN THE VICINITY OF THE MAGELLANIC CLOUDS

By Sergey E. Koposov, V. Belokurov, G. Torrealba, N. Evans II. 2015

378 citations recorded by the source corpus.

We have used the publicly released Dark Energy Survey (DES) data to hunt for new satellites of the Milky Way (MW) in the southern hemisphere. Our search yielded a large number of promising candidates. In this paper, we announce the discovery of nine new unambiguous ultra-faint objects, whose authenticity can be established with the DES data alone. Based on the morphological properties, three of the new satellites are dwarf galaxies, one of which is located at the very outskirts of the MW, at a distance of 380 kpc. The remaining six objects have sizes and luminosities comparable to the Segue 1 satellite and cannot be classified straightforwardly without follow-up spectroscopic observations. The satellites we have discovered cluster around the LMC and the SMC. We show that such spatial distribution is unlikely under the assumption of isotropy, and, therefore, conclude that at least some of the new satellites must have been associated with the Magellanic Clouds in the past.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/37f96af3e0cfac2bf0a85373a91b41f3f9faf505

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Citations in the corpus

A MegaCam Survey of Outer Halo Satellites. III. Photometric and Structural Parameters (2018, methodology): “…Jerjen 2015a); Hor II (Kim & Jerjen 2015c); Hyd II (Martin et al. 2015); Gru I (Koposov et al. 2015a); Ind I (Kim et al. 2015b; Bechtol et al. 2015; Koposov et al. 2015a); and Eri III, Hor I, Ret II, Eri II, Pic I and Pho II (Bechtol et al. 2015; Koposov et al. 2015a) Our analysis of these objects…”
The feeble giant. Discovery of a large and diffuse Milky Way dwarf galaxy in the constellation of Crater (2016, methodology): “The structural parameters of Crater 2 are determined by maximising the likelihood of a model describing the distribution of stars in the vicinity of the object (similar to e.g., Martin, de Jong & Rix 2008; Koposov et al. 2015).”
The hidden giant: discovery of an enormous Galactic dwarf satellite in Gaia DR2 (2018, methodology): “Photometry was carried out using the standard SEXTRACTOR + PSFEX combination (see e.g. Koposov et al. 2015a, for a similar approach).”
Small-Scale Challenges to the ΛCDM Paradigm (2017, background): “More recently the DES survey has continued this trend (Koposov et al. 2015; Drlica-Wagner et al. 2015).”
Mining for Dark Matter Substructure: Inferring Subhalo Population Properties from Strong Lenses with Machine Learning (2019, background): “While the detection of ultrafaint dwarf galaxies through the study of stellar overdensities and kinematics (Koposov et al. 2008, 2015; Bechtol et al. 2015; Drlica-Wagner et al. 2015) can be used to make statements about the underlying dark matter properties, theoretical uncertainties in the…”
Farthest Neighbor: The Distant Milky Way Satellite Eridanus II (2016, background): “Koposov et al. (2015) suggested that Eri II may contain a young stellar population component (∼250 Myr) due to the spatial coincidence of a few candidate blue loop stars, and therefore Eri II would be similar to the gas-rich dwarf Leo T, which is slightly more distant and more luminous (D = 420…”
SAGITTARIUS II, DRACO II AND LAEVENS 3: THREE NEW MILKY WAY SATELLITES DISCOVERED IN THE PAN-STARRS 1 3π SURVEY (2015, background): “These new satellites, located close to the Magellanic Clouds (Bechtol et al. 2015; Kirby et al. 2015; Koposov et al. 2015), have emphasized the tendency of these faint stellar systems to be brought into the MW surroundings in groups.”
The SAGA Survey. I. Satellite Galaxy Populations around Eight Milky Way Analogs (2017, background): “While the number of faint satellites (Mr > −10) is steadily increasing due to discoveries in ongoing large-area imaging surveys (e.g., Koposov et al. 2015; Drlica-Wagner et al. 2015), the number of bright satellites (Mr < −10) has remained unchanged since the discovery of the disrupting Sagittarius…”
EIGHT NEW MILKY WAY COMPANIONS DISCOVERED IN FIRST-YEAR DARK ENERGY SURVEY DATA (2015, background): “Koposov et al. (2015) identify nine candidate satellites of the Milky Way and/or Magellanic Clouds, including eight that overlap with candidates presented here.”
One Law to Rule Them All: The Radial Acceleration Relation of Galaxies (2016, background): “…et al. (2008), 22: Belokurov et al. (2007), 23: Muñoz et al. (2010), 24: Sand et al. (2009), 25: Adén et al. (2009), 26: Koposov et al. (2015a), 27: Koposov et al. (2015b), 28: Martin et al. (2015), 29: Kirby et al. (2015), 30: Moretti et al. (2009), 31: de Jong et al. (2010), 32: Walker et…”
DETAILED CHEMICAL ABUNDANCES IN THE r-PROCESS-RICH ULTRA-FAINT DWARF GALAXY RETICULUM 2 (2016, methodology): “Though located relatively close to the Large Magellanic Cloud (LMC), it remains unclear whether Ret 2 was originally a satellite of the Magellanic system (Koposov et al. 2015b).”
SEARCHING FOR DARK MATTER ANNIHILATION IN RECENTLY DISCOVERED MILKY WAY SATELLITES WITH FERMI-LAT (2016, methodology): “…recently discovered systems have measured kinematics consistent with being DM-dominated dSphs: Reticulum II (Simon et al. 2015; Walker et al. 2015a; Koposov et al. 2015b), Horologium I (Koposov et al. 2015b), Hydra II (Kirby et al. 2015b), Draco II (Martin et al. 2015b), Triangulum II (Kirby et…”
Sweating the small stuff: simulating dwarf galaxies, ultra-faint dwarf galaxies, and their own tiny satellites (2015, background): “6 Koposov et al. (2015) suggest that Eridanus II could possibly have a population of young stars in addition to the old stellar population.”
The upper bound on the lowest mass halo (2016, background): “In the bottom right panel of Figure 9, we show this for SDSS and DES as a function of the surveys’ r-band limiting magnitudes.”
Quenching and ram pressure stripping of simulated Milky Way satellite galaxies (2017, background): “Note that our stellar mass limit is significantly above the stellar masses of recently discovered MW satellite galaxies found in the Dark Energy Survey (Koposov et al. 2015; DrlicaWagner et al. 2015).”