Antlia Field Overview

The Antlia Field

Antlia Field


Antlia is a small low surface brightness dwarf spheroidal type galaxy whichwas discovered in 1997 to be an outlying member of the Local Group. Aspart of the FORS Science Verification program deep B, V and I images inexcellent seeing condisitons were made of the galaxy which resolve theindividual stars.

This galaxy was selected according to the following criteria:

  • Existence of published data indicating a distance close enough to be able to detect resolved stars well down the Red Giant Branch.
  • Optimal visibility throughout most part of the night in January-March (i.e. RA=8-11hr)
  • Some controversy about the existence and importance of a young stellar population and reddening in Antlia.

Science goals include:

  • Detailed study of the Colour-Magnitude diagrams to determine the properties of the resolved stellar population in  this small nearby, relatively isolated, galaxy
  • With the good seeing and sensitivity of these data it will be possible to determine if there is a young population from the presence or absense of a Main Sequence
  • See how the properties of a more distant dwarf spheriodal galaxy compare with those we see around our Galaxy
  • Study the reddening properties of this system with colour-colour diagrams
  • Confirm the distance to this system

Previous work on this galaxy comes from the discovery paper of Whiting,Irwin & Hau 1997, AJ, 114, 996 based on data taken with the CTIO~1.5mtelescope and deeper imaging from the CTIO~4m (by Sarajedini, Claver &Ostheimer 1997, AJ, 114, 2505) and the Las Campanas Dupont 2.5m telescope(by Aparicio et al. 1997, AJ, 114, 1447). This galaxy was first noted inan HI survey of southern hemisphere galaxies by Fouque et al. 1990, A&AS,86, 473.

 Antlia: RA(2000)= 10 04 04, DEC(2000)="-2"7 19 49 (l=263, b=22)