Streams on FIRE: Populations of Detectable Stellar Streams in the Milky Way and FIRE

Nora Shipp*, Nondh Panithanpaisal, Lina Necib, Robyn Sanderson, Denis Erkal, Ting S. Li, Isaiah B. Santistevan, Andrew Wetzel, Lara R. Cullinane, Alexander P. Ji, Sergey E. Koposov, Kyler Kuehn, Geraint F. Lewis, Andrew B. Pace, Daniel B. Zucker, Joss Bland-Hawthorn, Emily C. Cunningham, Stacy Y. Kim, Sophia Lilleengen, Jorge MorenoSanjib Sharma

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We present the first detailed comparison of populations of dwarf galaxy stellar streams in cosmological simulations and the Milky Way. In particular, we compare streams identified around 13 Milky Way analogs in the FIRE-2 simulations to streams observed by the Southern Stellar Stream Spectroscopic Survey (S 5). For an accurate comparison, we produce mock Dark Energy Survey (DES) observations of the FIRE streams and estimate the detectability of their tidal tails and progenitors. The number and stellar mass distributions of detectable stellar streams is consistent between observations and simulations. However, there are discrepancies in the distributions of pericenters and apocenters, with the detectable FIRE streams, on average, forming at larger pericenters (out to >110 kpc) and surviving only at larger apocenters (≳40 kpc) than those observed in the Milky Way. We find that the population of high-stellar-mass dwarf galaxy streams in the Milky Way is incomplete. Interestingly, a large fraction of the FIRE streams would only be detected as intact satellites in DES-like observations, since their tidal tails have too low surface brightness to be detectable. We thus predict a population of yet-undetected tidal tails around Milky Way satellites, as well as a population of fully undetected low-surface-brightness stellar streams, and estimate their detectability with the Rubin Observatory. Finally, we discuss the causes and implications of the discrepancies between the stream populations in FIRE and the Milky Way, and explore future avenues for tests of satellite disruption in cosmological simulations.

Original languageEnglish
Article number44
Pages (from-to)1-19
Number of pages19
JournalAstrophysical Journal
Volume949
Issue number2
DOIs
Publication statusPublished - 25 May 2023

Keywords / Materials (for Non-textual outputs)

  • astro-ph.GA

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