EDGE : The direct link between mass growth history and the extended stellar haloes of the faintest dwarf galaxies
(2024) In Monthly Notices of the Royal Astronomical Society 527(2). p.2403-2412- Abstract
Ultra-f aint dw arf galaxies (UFDs) are commonly found in close proximity to the Milky Way and other massive spiral galaxies. As such, their projected stellar ellipticity and extended light distributions are often thought to owe to tidal forces. In this paper, we study the projected stellar ellipticities and faint stellar outskirts of tidally isolated ultra-faints drawn from the 'Engineering Dwarfs at Galaxy Formation's Edge' (EDGE) cosmological simulation suite. Despite their tidal isolation, our simulated dwarfs exhibit a wide range of projected ellipticities (0.03 < ϵ < 0.85), with many possessing anisotropic extended stellar haloes that mimic tidal tails, but owe instead to late-time accretion of lower mass companions.... (More)
Ultra-f aint dw arf galaxies (UFDs) are commonly found in close proximity to the Milky Way and other massive spiral galaxies. As such, their projected stellar ellipticity and extended light distributions are often thought to owe to tidal forces. In this paper, we study the projected stellar ellipticities and faint stellar outskirts of tidally isolated ultra-faints drawn from the 'Engineering Dwarfs at Galaxy Formation's Edge' (EDGE) cosmological simulation suite. Despite their tidal isolation, our simulated dwarfs exhibit a wide range of projected ellipticities (0.03 < ϵ < 0.85), with many possessing anisotropic extended stellar haloes that mimic tidal tails, but owe instead to late-time accretion of lower mass companions. Furthermore, we find a strong causal relationship between ellipticity and formation time of a UFD, which is robust to a wide variation in the feedback model. We show that the distribution of projected ellipticities in our suite of simulated EDGE dwarfs matches well with a sample of 19 Local Group dwarf galaxies and a sample of 11 isolated dwarf galaxies. Given ellipticity in EDGE arises from an ex-situ accretion origin, the agreement in shape indicates the ellipticities of some observed dwarfs may also originate from a non-tidal scenario. The orbital parameters of these observed dwarfs further support that they are not currently tidally disrupting. If the baryonic content in these galaxies is still tidally intact, then the same may be true for their dark matter content, making these galaxies in our Local Group pristine laboratories for testing dark matter and galaxy formation models.
(Less)
- author
- organization
- publishing date
- 2024-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- dw arf, formation, galaxies, stellar content, structure
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 527
- issue
- 2
- pages
- 10 pages
- publisher
- Oxford University Press
- external identifiers
-
- scopus:85178350841
- ISSN
- 0035-8711
- DOI
- 10.1093/mnras/stad3354
- language
- English
- LU publication?
- yes
- id
- 6bc43876-08d5-4c61-b898-420a3658dd13
- date added to LUP
- 2023-12-18 14:39:03
- date last changed
- 2023-12-18 14:39:03
@article{6bc43876-08d5-4c61-b898-420a3658dd13,
abstract = {{<p>Ultra-f aint dw arf galaxies (UFDs) are commonly found in close proximity to the Milky Way and other massive spiral galaxies. As such, their projected stellar ellipticity and extended light distributions are often thought to owe to tidal forces. In this paper, we study the projected stellar ellipticities and faint stellar outskirts of tidally isolated ultra-faints drawn from the 'Engineering Dwarfs at Galaxy Formation's Edge' (EDGE) cosmological simulation suite. Despite their tidal isolation, our simulated dwarfs exhibit a wide range of projected ellipticities (0.03 < ϵ < 0.85), with many possessing anisotropic extended stellar haloes that mimic tidal tails, but owe instead to late-time accretion of lower mass companions. Furthermore, we find a strong causal relationship between ellipticity and formation time of a UFD, which is robust to a wide variation in the feedback model. We show that the distribution of projected ellipticities in our suite of simulated EDGE dwarfs matches well with a sample of 19 Local Group dwarf galaxies and a sample of 11 isolated dwarf galaxies. Given ellipticity in EDGE arises from an ex-situ accretion origin, the agreement in shape indicates the ellipticities of some observed dwarfs may also originate from a non-tidal scenario. The orbital parameters of these observed dwarfs further support that they are not currently tidally disrupting. If the baryonic content in these galaxies is still tidally intact, then the same may be true for their dark matter content, making these galaxies in our Local Group pristine laboratories for testing dark matter and galaxy formation models.</p>}},
author = {{Goater, Alex and Read, Justin I. and Noel, Noelia E.D. and Orkney, Matthew D.A. and Kim, Stacy Y. and Rey, Martin P. and Andersson, Eric P. and Agertz, Oscar and Pontzen, Andrew and Vieliute, Roberta and Kataria, Dhairya and Jeneway, Kiah}},
issn = {{0035-8711}},
keywords = {{dw arf; formation; galaxies; stellar content; structure}},
language = {{eng}},
number = {{2}},
pages = {{2403--2412}},
publisher = {{Oxford University Press}},
series = {{Monthly Notices of the Royal Astronomical Society}},
title = {{EDGE : The direct link between mass growth history and the extended stellar haloes of the faintest dwarf galaxies}},
url = {{http://dx.doi.org/10.1093/mnras/stad3354}},
doi = {{10.1093/mnras/stad3354}},
volume = {{527}},
year = {{2024}},
}