DDO 68: A FLEA WITH SMALLER FLEAS THAT PREY ON HIM

作者：Annibali Francesca^*; Nipoti Carlo; Ciotti Luca; Tosi Monica; Aloisi Alessandra; Bellazzini Michele; Cignoni Michele; Cusano Felice; Paris Diego; Sacchi Elena

来源：Astrophysical Journal Letters, 2016, 826(2): L27.

DOI：10.3847/2041-8205/826/2/L27

• galaxies: dwarf
• galaxies: formation
• galaxies: individual (DDO 68)
• galaxies: interactions
• galaxies: irregular
• galaxies: kinematics and dynamics

We present new photometry of the dwarf irregular galaxy DDO 68, one of the most metal-poor and least massive dwarfs, located in the Lynx-Cancer Void. The images were acquired with the Large Binocular Telescope in the g and r passbands and show unequivocally that DDO 68 has previously unknown stellar streams related to the accretion of at least two smaller companions: a flea with smaller fleas biting it, to put it in Jonathan Swift's words (from Jonathan Swift's On Poetry: a Rhapsody: So, naturalists observe, a flea/has smaller fleas that on him prey/and these have smaller still to bite em/and so proceed ad infinitum). Our data provide direct observational evidence of multiple galaxy merging occurring at very low galactic mass scales. We present the results of an N-body simulation of the interaction of three dwarf galaxies that reproduce well the main morphological features of DDO 68.

• 出版日期2016-8-1