We present new photometry of the dwarf irregular galaxy DDO68, 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 DDO68 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 DDO68.
Annibali, F., Nipoti, C., Ciotti, L., Tosi, M., Aloisi, A., Bellazzini, M., et al. (2016). DDO 68: A FLEA WITH SMALLER FLEAS THAT PREY ON HIM. THE ASTROPHYSICAL JOURNAL LETTERS, 826(L27), 1-6 [10.3847/2041-8205/826/2/L27].
DDO 68: A FLEA WITH SMALLER FLEAS THAT PREY ON HIM
ANNIBALI, FRANCESCA;NIPOTI, CARLO;CIOTTI, LUCA;TOSI, MONICA;CIGNONI, MICHELE;SACCHI, ELENA
2016
Abstract
We present new photometry of the dwarf irregular galaxy DDO68, 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 DDO68 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 DDO68.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
