Discovery of a new faint dwarf galaxy associated with NGC 253
| Autor: | Sand, D. J., Crnojević, D., Strader, J., Toloba, E., Simon, J. D., Caldwell, N., Guhathakurta, P., McLeod, B., Seth, A. C. |
|---|---|
| Rok vydání: | 2014 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1088/2041-8205/793/1/L7 |
| Popis: | We report the discovery of a new faint dwarf galaxy, which we dub Scl-MM-Dw1, at a projected distance of $\sim$65 kpc from the spiral galaxy NGC 253. The discovery results from the Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS), a program with the Magellan/Megacam imager to study faint substructure in resolved stellar light around massive galaxies outside of the Local Group. We measure a tip of the red giant branch distance to Scl-MM-Dw1 of $D$=3.9$\pm$0.5 Mpc, consistent with that of NGC 253, making their association likely. The new dwarf's stellar population is complex, with an old, metal poor red giant branch ($\gtrsim$10 Gyr, [Fe/H]$\sim$$-$2), and an asymptotic giant branch with an age of $\sim$500 Myr. Scl-MM-Dw1 has a half-light radius of $r_{h}$=340$\pm$50 pc and an absolute magnitude of $M_{V}$=$-$10.3$\pm$0.6 mag, comparable to the Milky Way's satellites at the same luminosity. Once complete, our imaging survey of NGC 253 and other nearby massive galaxies will provide a census of faint substructure in halos beyond the Local Group, both to put our own environment into context and to confront models of hierarchical structure formation. Comment: 8 pages, 4 figures, ApJL submitted |
| Databáze: | arXiv |
| Externí odkaz: |
|