The no-spin zone: rotation vs dispersion support in observed and simulated dwarf galaxies
Abstract
We perform a systematic Bayesian analysis of rotation vs. dispersion support (v_(rot)/σ) in 40 dwarf galaxies throughout the Local Volume (LV) over a stellar mass range 10^(3.5) M_⊙ < M⋆ < 10^8 M_⊙. We find that the stars in ∼90% of the LV dwarf galaxies studied -- both satellites and isolated systems -- are dispersion-supported. In particular, we show that 7/10 *isolated* dwarfs in our sample have stellar populations with v_(rot)/σ<0.6. All have v_(rot)/σ≲2. These results challenge the traditional view that the stars in gas-rich dwarf irregulars (dIrrs) are distributed in cold, rotationally-supported stellar disks, while gas-poor dwarf spheroidals (dSphs) are kinematically distinct in having dispersion-supported stars. We see no clear trend between v_(rot)/σ and distance to the closest L⋆ galaxy, nor between v_(rot)/σ and M⋆ within our mass range. We apply the same Bayesian analysis to four FIRE hydrodynamic zoom-in simulations of isolated dwarf galaxies (10^9M⊙
Additional Information
© 2016 Oxford University Press. Received: 03 November 2015. Revision Received: 04 October 2016. Accepted: 04 October 2016. Published: 08 October 2016. We thank the anonymous referee, for comments that made the paper clearer and more robust. We also thank Josh Simon, Marla Geha, Ngoc Nhung Ho, Nicolas Martin, Serge Demers, Evan Kirby, and Ryan Leaman for generously providing their data for this project. We further thank Ryan Leaman and Evan Kirby for very helpful discussions. This work used computational resources granted by NASA Advanced Supercomputing (NAS) Division, NASA Center for Climate Simulation, Teragrid, and by the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant numbers OCI-1053575 and ACI-1053575, the latter through allocation AST140080 (PI: Boylan-Kolchin). CW acknowledges support from the Josephine de Karman Fellowship Trust. CW and JB were supported in part by Hubble Space Telescope grants HST-AR-13921.002-A and HST-AR-13888.003-A. MBK acknowledges support from NASA through Hubble Space Telescope theory grants (programs AR-12836 and AR-13888) from the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. MBK and AF acknowledge support from NSF grant AST-1517226. OE acknowledges funds from NSF grant NSF-AST 1518291 and Hubble Space Telescope grant HST-GO-13343.09-A. Support for PFH was provided by an Alfred P. Sloan Research Fellowship, NASA ATP Grant NNX14AH35G, and NSF Collaborative Research Grant #1411920 and CAREER grant #1455342. Some numerical calculations were run on the Caltech compute cluster 'Zwicky' (NSF MRI award #PHY-0960291) and allocation TG-AST130039 granted by the Extreme Science and Engineering Discovery Environment (XSEDE) supported by the NSF. DK received support from XSEDE allocation TG-AST-120025 (PI: Kereš) National Science Foundation grant number AST-1412153, and funds from the University of California, San Diego.Attached Files
Published - stw2583.pdf
Submitted - 1511.01095v1.pdf
Files
1511.01095v1.pdf
Additional details
Identifiers
- Eprint ID
- 62187
- Resolver ID
- CaltechAUTHORS:20151118-080725780
Related works
- Describes
- http://arxiv.org/abs/1511.01095 (URL)
Funding
- NSF
- OCI-1053575
- NSF
- ACI-1053575
- NSF
- AST-140080
- Josephine de Karman Fellowship Trust
- NASA
- HST-AR-13921.002-A
- NASA
- HST-AR-13888.003-A
- NASA Hubble Fellowship
- AR-12836
- NASA Hubble Fellowship
- AR-13888
- NASA
- NAS5-26555
- NSF
- AST-1517226
- NSF
- AST-1518291
- NASA
- HST-GO-13343.09-A
- Alfred P. Sloan Foundation
- NASA
- NNX14AH35G
- NSF
- AST-1411920
- NSF
- AST-1455342
- NSF
- PHY-0960291
- NSF
- TG-AST-130039
- NSF
- TG-AST-120025
- NSF
- AST-1412153
- University of California, San Diego
Dates
- Created
-
2015-11-18Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
Caltech Custom Metadata
- Caltech groups
- TAPIR , Astronomy Department