Nearby dwarf galaxy in Magellanic bridge : J/MNRAS/479/5343


Authors : Koposov S.E. orcid , Walker M.G., Belokurov V. (hide) , Walker M.G., Belokurov V. et..al

Bibcode : 2018MNRAS.479.5343K (ADS) (Simbad) (Objects) (hide)

CDS Keywords : Galaxies; Clusters, globular; Magellanic Clouds; Optical
UAT : Galaxies, Globular star clusters, Magellanic Clouds, Optical astronomy

Observation (OC)

Records :

Inserted into VizieR : 06-May-2022
Last modification : 18-Aug-2024

Snake in the Clouds A new nearby dwarf galaxy in the Magellanic bridge*. (2018)

Keywords : stars general - globular clusters: general - Galaxy: halo - galaxies: dwarf - Local Group - Magellanic Clouds

Abstract:We report the discovery of a nearby dwarf galaxy in the constellation of Hydrus, between the Large (LMC) and the Small Magellanic Clouds (SMC). Hydrus 1 is a mildly elliptical ultrafaint system with luminosity M_V_~-4.7 and size 53+/-3pc, located 28kpc from the Sun and 24kpc from the LMC. From spectroscopy of ~30 member stars, we measure a velocity dispersion of 2.7+/-0.5 km/s and find tentative evidence for a radial velocity gradient consistent with 3km/s rotation. Hydrus 1's velocity dispersion indicates that the system is dark matter dominated, but its dynamical mass-to-light ratio M/L=66^+29^_-20_ is significantly smaller than typical for ultrafaint dwarfs at similar luminosity. The kinematics and spatial position of Hydrus 1 make it a ...(more)
Abstract: (hide)
This work utilizes the photometric data from two DECam programs, 2016A-0618 and 2017B-0906, focusing on the region between the MCs. On 2018 February 12-13, we used M2FS, a multi-object fiber spectrograph at the Magellan Clay 6.5m telescope, to acquire spectra for the selected targets. Table 2 presents spectroscopic parameter measurements for all the stars that either have S/N larger than 3 or have RV uncertainty less than 10km/s. We list measurements of the effective temperature, surface gravity, metallicity, and heliocentric LOS velocity. We also provide in the table, the g, r magnitudes and the log odds of being Hydrus 1 member star, based on the model described in the next section.


                
Catalogue provenance