FIGGS Faint Irregular Galaxies GMRT Survey

The Faint Irregular Galaxies GMRT Survey (FIGGS) is a large program aimed at providing a comprehensive and statistically robust characterisation of the neutral ISM properties of faint (M_B > -14.5), nearby, gas rich, dwarf irregular galaxies using the Gian

FIGGS: Faint Irregular Galaxies GMRT Survey arXiv:0711.1807v1 [astro-ph] 12 Nov 2007 Ayesha Begum1 , Jayaram N. Chengalur2 , Igor D. Karachentsev3, Margrita Sharina3 , and Sera m Kaisin3 1 2 3 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge ayesha@ast.cam.ac.uk National Centre for Radio Astrophysics, TIFR, Pune University Campus, Ganeshkhind, Pune Special Astrophysical Observatory, Nizhnii Arkhys 369167, Russia 1 Introduction HI 21cm aperture synthesis observations of spiral galaxies is a mature eld with over two decades of history – probably something of the order of a thousand galaxies have already been imaged. However, the observations have tended to focus on bright (～ L ) galaxies with HI masses ～ 109 M⊙ . Dwarf galaxies (MB > 17) require substantial investments of telescope time, and have hence not been studied in similar numbers. To start addressing this imbalance, we have been conducting an HI imaging study of faint dwarf galaxies the Faint Irregular Galaxies GMRT Survey (FIGGS). The immediate goal of FIGGS is to obtain high quality observations of the atomic ISM in a large, volume limited sample of faint, gas rich, dwarf irregular galaxies. Here we brie y describe the survey and discuss some of the science that we anticipate can be done with this data set. 1.1 FIGGS Sample The FIGGS galaxies form an HI ux limited subsample of the Karachentsev et al.(2004) catalog of galaxies within 10 Mpc. Speci cally, the FIGGS sample consists of 65 faint dwarf irregular (dIrr) galaxies with MB > 14.5, HI ux integral > 1 Jy kms 1 and optical sizes > 1 arcmin. The FIGGS galaxies represent the extreme low-mass end of the dIrr population, with a median MB ～ 13 and a median HI mass ～ 3 × 107 M⊙ . Fig. 1 compares the distributions of gas fraction, luminosity and dynamical mass of the FIGGS galaxies with that of existing samples of galaxies with HI aperture synthesis observations. As can be seen, the FIGGS survey substantially extends the region of parameter space which has largely gone untouched by previous HI imaging studies.

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