TY - JOUR
T1 - NIHAO XXI
T2 - The emergence of low surface brightness galaxies
AU - Di Cintio, Arianna
AU - Brook, Chris B.
AU - MacCiò, Andrea V.
AU - Dutton, Aaron A.
AU - Cardona-Barrero, Salvador
N1 - Funding Information:
ADC acknowledges financial support from a Marie-Skłodowska-Curie Individual Fellowship grant, H2020-MSCA-IF-2016 Grant agreement 748213, DIGESTIVO. CBB thanks MINECO/FEDER grant AYA2015-63810-P and the Ramón y Cajal fellowship program. ADC acknowledges fruitful discussions with Julio Navarro, Laura Sales, and Patricia Sánchez-Blázquez. This research was carried out on the High Performance Computing resources at New York University Abu Dhabi. Additional computational resources were provided by the THEO cluster at MPIA and the HYDRA clusters at Rechenzentrum in Garching.
Publisher Copyright:
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
PY - 2019/6/1
Y1 - 2019/6/1
N2 - The existence of galaxies with a surface brightness μ lower than the night sky has been known since three decades. Yet, their formation mechanism and emergence within a Lambda cold dark matter universe has remained largely undetermined. For the first time, we investigated the origin of low surface brightness (LSB) galaxies with Mθ ∼ 109.5-10Mθ, which we are able to reproduce within hydrodynamical cosmological simulations from the NIHAO suite. The simulated and observed LSB galaxies share similar properties, having large HI reservoir, extended star formation histories and effective radii, lowSérsic index, and slowly rising rotation curves. The formation mechanism of these objects is explored: simulated LSB galaxies form as a result of coplanar co-rotating mergers and aligned accretion of gas at early times, while perpendicular mergers and misaligned gas accretion result in higher μ galaxies by z = 0. The larger the merger, the stronger the correlation between merger orbital configuration and final μ. While the halo spin parameter is consistently high in simulated LSB galaxies, the impact of halo concentration, feedback-driven gas outflows, and merger time only plays a minorto- no role in determining μ. Interestingly, the formation scenario of such 'classical' LSB galaxies differs from the one of less massive, Mθ ∼ 107-9Mθ, ultra-diffuse galaxies, the latter resulting from the effects of SNae-driven gas outflows: an Mθ of ∼109Mθ thus represents the transition regime between a feedback-dominated to an angular-momentum-dominated formation scenario in the LSB realm. Observational predictions are offered regarding spatially resolved star formation rates through LSB discs: these, together with upcoming surveys, can be used to verify the proposed emergence scenario of LSB galaxies.
AB - The existence of galaxies with a surface brightness μ lower than the night sky has been known since three decades. Yet, their formation mechanism and emergence within a Lambda cold dark matter universe has remained largely undetermined. For the first time, we investigated the origin of low surface brightness (LSB) galaxies with Mθ ∼ 109.5-10Mθ, which we are able to reproduce within hydrodynamical cosmological simulations from the NIHAO suite. The simulated and observed LSB galaxies share similar properties, having large HI reservoir, extended star formation histories and effective radii, lowSérsic index, and slowly rising rotation curves. The formation mechanism of these objects is explored: simulated LSB galaxies form as a result of coplanar co-rotating mergers and aligned accretion of gas at early times, while perpendicular mergers and misaligned gas accretion result in higher μ galaxies by z = 0. The larger the merger, the stronger the correlation between merger orbital configuration and final μ. While the halo spin parameter is consistently high in simulated LSB galaxies, the impact of halo concentration, feedback-driven gas outflows, and merger time only plays a minorto- no role in determining μ. Interestingly, the formation scenario of such 'classical' LSB galaxies differs from the one of less massive, Mθ ∼ 107-9Mθ, ultra-diffuse galaxies, the latter resulting from the effects of SNae-driven gas outflows: an Mθ of ∼109Mθ thus represents the transition regime between a feedback-dominated to an angular-momentum-dominated formation scenario in the LSB realm. Observational predictions are offered regarding spatially resolved star formation rates through LSB discs: these, together with upcoming surveys, can be used to verify the proposed emergence scenario of LSB galaxies.
KW - cosmology: theory.
KW - dark matter
KW - galaxies: evolution
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U2 - 10.1093/mnras/stz985
DO - 10.1093/mnras/stz985
M3 - Article
AN - SCOPUS:85067987905
VL - 486
SP - 2535
EP - 2548
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -