The Archetypal Ultra-diffuse Galaxy, Dragonfly 44, Is not a Dark Milky Way

Bogdán, Ákos (2020) The Archetypal Ultra-diffuse Galaxy, Dragonfly 44, Is not a Dark Milky Way. The Astrophysical Journal, 901 (2). L30. ISSN 2041-8213

[thumbnail of Bogdán_2020_ApJL_901_L30.pdf] Text
Bogdán_2020_ApJL_901_L30.pdf - Published Version

Download (541kB)


Due to the peculiar properties of ultra-diffuse galaxies (UDGs), understanding their origin presents a major challenge. Previous X-ray studies demonstrated that the bulk of UDGs lack substantial X-ray emission, implying that they reside in low-mass dark matter halos. This result, in concert with other observational and theoretical studies, pointed out that most UDGs belong to the class of dwarf galaxies. However, a subset of UDGs is believed to host a large population of globular clusters (GCs), which is indicative of massive dark matter halos. This, in turn, hints that some UDGs may be failed L⋆ galaxies. In this work, I present Chandra and XMM-Newton observations of two archetypal UDGs, Dragonfly 44 and DF X1, and I constrain their dark matter halo mass based on the X-ray emission originating from hot gaseous emission and from the population of low-mass X-ray binaries residing in GCs. Both Dragonfly 44 and DF X1 remain undetected in X-rays. The upper limits on the X-ray emission exclude the possibility that these galaxies reside in massive (Mvir ≳ 5 × 1011 M⊙) dark matter halos, suggesting that they are not failed L⋆ galaxies. These results demonstrate that even these iconic UDGs resemble to dwarf galaxies with Mvir ≲ 1011 M⊙, implying that UDGs represent a single galaxy population.

Item Type: Article
Subjects: Eprints STM archive > Physics and Astronomy
Depositing User: Unnamed user with email admin@eprints.stmarchive
Date Deposited: 22 May 2023 07:05
Last Modified: 26 Dec 2023 04:53

Actions (login required)

View Item
View Item