This paper presents a newly established sample of 103 unique galaxies or galaxy groups at 0.4 ≲ z ≲ 0.7 from the Cosmic Ultraviolet Baryon Survey (CUBS) for studying the warm-hot circumgalactic medium (CGM) probed by both O vi and Ne viii absorption. The galaxies and associated neighbors are identified at <1 physical Mpc from the sightlines toward 15 CUBS QSOs at z QSO ≳ 0.8. A total of 30 galaxies or galaxy groups exhibit associated O vi λ λ 1031, 1037 doublet absorption within a line-of-sight velocity interval of ±250 km s−1, while the rest show no trace of O vi to a detection limit of log N OVI / cm − 2 ≈ 13.7 . Meanwhile, only five galaxies or galaxy groups exhibit the Ne viii λ λ 770, 780 doublet absorption, down to a limiting column density of log N NeVIII / cm − 2 ≈ 14.0 . These O vi- and Ne viii-bearing halos reside in different galaxy environments with stellar masses ranging from log M star / M ⊙ ≈ 8 to ≈11.5. The warm-hot CGM around galaxies of different stellar masses and star formation rates exhibits different spatial profiles and kinematics. In particular, star-forming galaxies with log M star / M ⊙ ≈ 9 - 11 show a significant concentration of metal-enriched warm-hot CGM within the virial radius, while massive quiescent galaxies exhibit flatter radial profiles of both column densities and covering fractions. In addition, the velocity dispersion of O vi absorption is broad with σ υ > 40 km s−1 for galaxies of log M star / M ⊙ > 9 within the virial radius, suggesting a more dynamic warm-hot halo around these galaxies. Finally, the warm-hot CGM probed by O vi and Ne viii is suggested to be the dominant phase in sub-L* galaxies with log M star / M ⊙ ≈ 9 - 10 based on their high ionization fractions in the CGM.
Qu, Z., Chen, H., Johnson, S., Rudie, G., Zahedy, F., Depalma, D., et al. (2024). The Cosmic Ultraviolet Baryon Survey (CUBS). VII. On the Warm-hot Circumgalactic Medium Probed by O vi and Ne viii at 0.4 ≲ z ≲ 0.7. THE ASTROPHYSICAL JOURNAL, 968(1) [10.3847/1538-4357/ad410b].
The Cosmic Ultraviolet Baryon Survey (CUBS). VII. On the Warm-hot Circumgalactic Medium Probed by O vi and Ne viii at 0.4 ≲ z ≲ 0.7
Cantalupo S.;
2024
Abstract
This paper presents a newly established sample of 103 unique galaxies or galaxy groups at 0.4 ≲ z ≲ 0.7 from the Cosmic Ultraviolet Baryon Survey (CUBS) for studying the warm-hot circumgalactic medium (CGM) probed by both O vi and Ne viii absorption. The galaxies and associated neighbors are identified at <1 physical Mpc from the sightlines toward 15 CUBS QSOs at z QSO ≳ 0.8. A total of 30 galaxies or galaxy groups exhibit associated O vi λ λ 1031, 1037 doublet absorption within a line-of-sight velocity interval of ±250 km s−1, while the rest show no trace of O vi to a detection limit of log N OVI / cm − 2 ≈ 13.7 . Meanwhile, only five galaxies or galaxy groups exhibit the Ne viii λ λ 770, 780 doublet absorption, down to a limiting column density of log N NeVIII / cm − 2 ≈ 14.0 . These O vi- and Ne viii-bearing halos reside in different galaxy environments with stellar masses ranging from log M star / M ⊙ ≈ 8 to ≈11.5. The warm-hot CGM around galaxies of different stellar masses and star formation rates exhibits different spatial profiles and kinematics. In particular, star-forming galaxies with log M star / M ⊙ ≈ 9 - 11 show a significant concentration of metal-enriched warm-hot CGM within the virial radius, while massive quiescent galaxies exhibit flatter radial profiles of both column densities and covering fractions. In addition, the velocity dispersion of O vi absorption is broad with σ υ > 40 km s−1 for galaxies of log M star / M ⊙ > 9 within the virial radius, suggesting a more dynamic warm-hot halo around these galaxies. Finally, the warm-hot CGM probed by O vi and Ne viii is suggested to be the dominant phase in sub-L* galaxies with log M star / M ⊙ ≈ 9 - 10 based on their high ionization fractions in the CGM.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.