Bibcode
Trujillo, I.; Roman, J.; Filho, M.; Sánchez Almeida, J.
Bibliographical reference
The Astrophysical Journal, Volume 836, Issue 2, article id. 191, 6 pp. (2017).
Advertised on:
2
2017
Journal
Citations
81
Refereed citations
75
Description
We describe the structural, stellar population and gas properties of the
nearest ultra diffuse galaxy discovered so far: UGC 2162 (z = 0.00392
{R}e,g=1.7(+/- 0.2) kpc; {μ }g(0) = 24.4
± 0.1 mag arcsec‑2 g-i = 0.33 ± 0.02).
This galaxy, located at a distance of 12.3(±1.7) Mpc, is a member
of the M77 group. UGC 2162 has a stellar mass of ∼
2{(}-1+2) × 107 {M}ȯ
and is embedded within a cloud of HI gas ∼10 times more
massive: ∼1.9(±0.6) × 108 {M}ȯ
. Using the width of its HI line as a dynamical proxy, the
enclosed mass within the inner R ∼ 5 kpc is ∼4.6(±0.8)
× 109 {M}ȯ (i.e., M/L ∼ 200). The
estimated virial mass from the cumulative mass curve is
∼8(±2)×1010 M ⊙. Ultra-deep
imaging from the IAC Stripe82 Legacy Project show that the galaxy is
irregular and has many star-forming knots, with a gas-phase metallicity
around one-third of the solar value. Its estimated star-formation rate
is ∼0.01 {M}ȯ yr‑1. This SFR would
double the stellar mass of the object in ∼2 Gyr. If the object were
to stop forming stars at this moment, after a passive evolution, its
surface brightness would become extremely faint: {μ }g(0)
∼ 27 mag arcsec‑2 and its size would remain large
{R}e,g ∼ 1.8 kpc. Such faintness would make it almost
undetectable to most present-day surveys. This suggests that there could
be an important population of {M}\star ∼ 107
{M}ȯ “dark galaxies” in rich environments
(depleted of HI gas) waiting to be discovered by current and future
ultra-deep surveys.
Related projects
Starbursts in Galaxies GEFE
Starsbursts play a key role in the cosmic evolution of galaxies, and thus in the star formation (SF) history of the universe, the production of metals, and the feedback coupling galaxies with the cosmic web. Extreme SF conditions prevail early on during the formation of the first stars and galaxies, therefore, the starburst phenomenon constitutes a
Casiana
Muñoz Tuñón
Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
Ignacio
Martín Navarro