The Red Dead Redemption Survey of Circumgalactic Gas about Massive Galaxies. I. Mass and Metallicity of the Cool Phase

Berg, Michelle A.; Howk, J. C.; Lehner, N.; Wotta, Christopher B.; O’Meara, John M.; Bowen, David V.; Burchett, Joseph N.; Peeples, Molly S.; Tejos, Nicolás

doi:10.3847/1538-4357/ab378e

Cited by 41 publications

(45 citation statements)

References 147 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While it can be shown that the required gas could plausibly exist in the cluster, perhaps in the form of cloudlets of ∼10 4 K photoionised gas that often envelop elliptical galaxies (e.g. Gauthier, Chen, & Tinker 2010;Thom et al 2012;Prochaska et al 2013;Farnes et al 2017;Lan & Fukugita 2017;Berg et al 2019;Pradeep et al 2019;Werner et al 2019;Liang & Remming 2020), we can test this scenario using the frequency dependence of the effect. Consider that the free-free optical depth is given by:…”

Section: Evaluation Of the Decrements And Enhancements In Source Counmentioning

confidence: 99%

Early Science from POSSUM: Shocks, turbulence, and a massive new reservoir of ionised gas in the Fornax cluster

Anderson

Heald

Eilek

et al. 2021

Publ. Astron. Soc. Aust.

View full text Add to dashboard Cite

We present the first Faraday rotation measure (RM) grid study of an individual low-mass cluster—the Fornax cluster—which is presently undergoing a series of mergers. Exploiting commissioning data for the POlarisation Sky Survey of the Universe’s Magnetism (POSSUM) covering a ${\sim}34$ square degree sky area using the Australian Square Kilometre Array Pathfinder (ASKAP), we achieve an RM grid density of ${\sim}25$ RMs per square degree from a 280-MHz band centred at 887 MHz, which is similar to expectations for forthcoming GHz-frequency ${\sim}3\pi$ -steradian sky surveys. These data allow us to probe the extended magnetoionic structure of the cluster and its surroundings in unprecedented detail. We find that the scatter in the Faraday RM of confirmed background sources is increased by $16.8\pm2.4$ rad m−2 within 1 $^\circ$ (360 kpc) projected distance to the cluster centre, which is 2–4 times larger than the spatial extent of the presently detectable X-ray-emitting intracluster medium (ICM). The mass of the Faraday-active plasma is larger than that of the X-ray-emitting ICM and exists in a density regime that broadly matches expectations for moderately dense components of the Warm-Hot Intergalactic Medium. We argue that forthcoming RM grids from both targeted and survey observations may be a singular probe of cosmic plasma in this regime. The morphology of the global Faraday depth enhancement is not uniform and isotropic but rather exhibits the classic morphology of an astrophysical bow shock on the southwest side of the main Fornax cluster, and an extended, swept-back wake on the northeastern side. Our favoured explanation for these phenomena is an ongoing merger between the main cluster and a subcluster to the southwest. The shock’s Mach angle and stand-off distance lead to a self-consistent transonic merger speed with Mach 1.06. The region hosting the Faraday depth enhancement also appears to show a decrement in both total and polarised radio emission compared to the broader field. We evaluate cosmic variance and free-free absorption by a pervasive cold dense gas surrounding NGC 1399 as possible causes but find both explanations unsatisfactory, warranting further observations. Generally, our study illustrates the scientific returns that can be expected from all-sky grids of discrete sources generated by forthcoming all-sky radio surveys.

show abstract

Section: Evaluation Of the Decrements And Enhancements In Source Counmentioning

confidence: 99%

Early Science from POSSUM: Shocks, turbulence, and a massive new reservoir of ionised gas in the Fornax cluster

Anderson

Heald

Eilek

et al. 2021

Publ. Astron. Soc. Aust.

View full text Add to dashboard Cite

show abstract

“…The photoionized gas around z1 galaxies is very chemically inhomogeneous, as shown by large metallicity ranges and the large metallicity variations among kinematically distinct components in a single halo (Lehner et al 2019;Wotta et al 2019; see also Crighton et al 2013;Muzahid et al 2015Muzahid et al , 2016Rosenwasser et al 2018). Such a large metallicity variation is observed not only in the CGM of star-forming galaxies but also in the CGM of passive and massive galaxies, where there appears to be as much cold, bound H I gas as in their starforming counterparts (e.g., Thom et al 2012;Tumlinson et al 2013;Berg et al 2019;Zahedy et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Project AMIGA: The Circumgalactic Medium of Andromeda*

Lehner

Berek

Howk

et al. 2020

ApJ

Self Cite

View full text Add to dashboard Cite

Project AMIGA (Absorption Maps In the Gas of Andromeda) is a survey of the circumgalactic medium (CGM) of Andromeda (M31, R vir ;300 kpc) along 43 QSO sightlines at impact parameters 25 R569 kpc (25 at RR vir). We use ultraviolet absorption measurements of Si II, Si III, Si IV, C II, and C IV from the Hubble Space Telescope/Cosmic Origins Spectrograph and O VI from the Far Ultraviolet Spectroscopic Explorer to provide an unparalleled look at how the physical conditions and metals are distributed in the CGM of M31. We find that Si III and O VI have a covering factor near unity for R1.2 R vir and 1.9 R vir , respectively, demonstrating that M31 has a very extended ∼10 4-10 5.5 K ionized CGM. The metal and baryon masses of the 10 4-10 5.5 K CGM gas within R vir are 10 8 and 4×10 10 (Z/0.3 Z e) −1 M e , respectively. There is not much azimuthal variation in the column densities or kinematics, but there is with R. The CGM gas at R0.5 R vir is more dynamic and has more complicated, multiphase structures than at larger radii, perhaps a result of more direct impact of galactic feedback in the inner regions of the CGM. Several absorbers are projected spatially and kinematically close to M31 dwarf satellites, but we show that those are unlikely to give rise to the observed absorption. Cosmological zoom simulations of ∼L * galaxies have O VI extending well beyond R vir as observed for M31 but do not reproduce well the radial column density profiles of the lower ions. However, some similar trends are also observed, such as the lower ions showing a larger dispersion in column density and stronger dependence on R than higher ions. Based on our findings, it is likely that the Milky Way has a ∼10 4-10 5.5 K CGM as extended as for M31 and their CGM (especially the warm-hot gas probed by O VI) are overlapping.

show abstract

“…Cold circumgalactic medium (CGM) gas makes up a substantial fraction (30%-50%) of galactic baryons (Werk et al 2014) and may accrete onto galaxies to fuel star formation. It is then particularly intriguing that the CGMs of some quenched galaxies are observed to have massive reservoirs of cold gas (Thom et al 2012;Berg et al 2019). How these galaxies remain quenched despite these large cold gas reservoirs is uncertain.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Cosmic Rays on Thermal Instability in the Circumgalactic Medium

Butsky

Fielding

Hayward

et al. 2020

ApJ

View full text Add to dashboard Cite

Large reservoirs of cold (∼10 4 K) gas exist out to and beyond the virial radius in the circumgalactic medium (CGM) of all types of galaxies. Photoionization modeling suggests that cold CGM gas has significantly lower densities than expected by theoretical predictions based on thermal pressure equilibrium with hot CGM gas. In this work, we investigate the impact of cosmic-ray physics on the formation of cold gas via thermal instability. We use idealized three-dimensional magnetohydrodynamic simulations to follow the evolution of thermally unstable gas in a gravitationally stratified medium. We find that cosmic-ray pressure lowers the density and increases the size of cold gas clouds formed through thermal instability. We develop a simple model for how the cold cloud sizes and the relative densities of cold and hot gas depend on cosmic-ray pressure. Cosmic-ray pressure can help counteract gravity to keep cold gas in the CGM for longer, thereby increasing the predicted cold mass fraction and decreasing the predicted cold gas inflow rates. Efficient cosmic-ray transport, by streaming or diffusion, redistributes cosmicray pressure from the cold gas to the background medium, resulting in cold gas properties that are in between those predicted by simulations with inefficient transport and simulations without cosmic rays. We show that cosmic rays can significantly reduce galactic accretion rates and resolve the tension between theoretical models and observational constraints on the properties of cold CGM gas.

show abstract

The Red Dead Redemption Survey of Circumgalactic Gas about Massive Galaxies. I. Mass and Metallicity of the Cool Phase

Cited by 41 publications

References 147 publications

Early Science from POSSUM: Shocks, turbulence, and a massive new reservoir of ionised gas in the Fornax cluster

Early Science from POSSUM: Shocks, turbulence, and a massive new reservoir of ionised gas in the Fornax cluster

Project AMIGA: The Circumgalactic Medium of Andromeda*

The Impact of Cosmic Rays on Thermal Instability in the Circumgalactic Medium

Contact Info

Product

Resources

About