NOAO >   Observing Info >   Approved Programs >   2017B-0177

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Program Information for 2017B-0177


PI: Blair Conn, Australian National U., blair.conn@anu.edu.au
Address: Research School of Astronomy & Astrophysics, MOUNT STROMLO OBSERVATORY COTTER ROAD, WESTON CREEK, ACT 2611 Australia

CoI: Helmut Jerjen, Australian National U.
CoI: Dongwon Kim, Australian National U.
CoI: Mischa Schirmer, Gemini Observatory

Title: A Census of Satellites: Morphology, Metallicity and Mass Segregation in the newest MW Satellites

Abstract: In Semester 16B, our team was awarded 9 hours to follow-up 7 of the new ultra-faint Milky Way satellites with GMOS-S. Subsequently the extremely high quality of this dataset means we now have the deepest datasets on each of these objects and are able to determine their properties to a precision not typically seen in this field. Our first paper on 2 of these objects is nearing completion and we have provided new constraints on their distance, size, ellipticity and stellar populations. We are also using this deep photometry to investigate whether there is any evidence of extra-tidal stars or mass segregation in these systems because these properties are expected in low mass star clusters but unexpected in dark matter dominated MW satellite galaxies. Deep GMOS-S photometry means we can probe this transition zone in the size-luminosity plane between star clusters and ultra-faint dwarf galaxies. We propose to extend our successful campaign to include 7 more ultra-faint stellar systems that reside in this transition zone. As per our 16B proposal, the photometry will probe into the main sequence of these stellar systems. The measurements will (i) establish the main sequence mass function and estimate the binary fraction and (ii) provide more accurate fundamental parameters for each stellar system, including the total luminosity, age, metallicity, extra-tidal stellar features, and will (iii) test mass segregation as new diagnostic tool to discriminate between dark matter dominated MW satellite galaxies and pure baryonic stellar systems.

Program Type: Standard/Galactic

Scheduled Nights:
Run 2 (2017B):  GEM-SQ/GMOSS -- 5.5hrs band 2 (GS-2017B-Q-40)


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2017B-0177

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