The Deepest Chandra View of RBS 797: Evidence for Two Pairs of Equidistant X-ray Cavities

Ubertosi, Francesco; Gitti, Myriam; Brighenti, Fabrizio; Brunetti, G.; McDonald, Michael; Nulsen, P. E. J.; McNamara, B. R.; Randall, Scott W.; Forman, W.; Donahue, M.; Ignesti, Alessandro; Gaspari, M.; Ettori, S.; Feretti, L.; Blanton, E. L.; Jones, C.; Calzadilla, Michael S.

doi:10.3847/2041-8213/ac374c

“…visually similar to the pair of X-ray cavities observed in RBS 797 (Ubertosi et al 2021) (see also Figure 3). In the right column, even though the bow shock has outrun the accretion shock and the jets have reached ∼7R B ; 1 kpc, we can still see the old jet-inflated remnant cavities closer to the BH.…”

Section: Shocks and Cavities In Synthetic X-ray Imagessupporting

confidence: 79%

Bridging the Bondi and Event Horizon Scales: 3D GRMHD Simulations Reveal X-shaped Radio Galaxy Morphology

Lalakos¹,

Gottlieb²,

Kaaz³

et al. 2022

ApJL

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X-shaped radio galaxies (XRGs) produce misaligned X-shaped jet pairs and make up ≲10% of radio galaxies. XRGs are thought to emerge in galaxies featuring a binary supermassive black hole (SMBH), SMBH merger, or large-scale ambient medium asymmetry. We demonstrate that XRG morphology can naturally form without such special, preexisting conditions. Our 3D general-relativistic magnetohydrodynamic (GRMHD) simulation for the first time follows magnetized rotating gas from outside the SMBH sphere of influence of radius R B to the SMBH of gravitational radius R g at the largest scale separation, R B/R g = 103, to date. Initially, our axisymmetric system of constant-density hot gas contains a weak vertical magnetic field and rotates in the equatorial plane of a rapidly spinning SMBH. We seed the gas with small-scale 2% level pressure perturbations. Infalling gas forms an accretion disk, and the SMBH launches relativistically magnetized collimated jets reaching well outside R B. Under the pressure of the infalling gas, the jets intermittently turn on and off, erratically wobble, and inflate pairs of cavities in different directions, resembling an X-shaped jet morphology. Synthetic X-ray images reveal multiple pairs of jet-powered shocks and cavities. Large-scale magnetic flux accumulates on the SMBH, becomes dynamically important, and leads to a magnetically arrested disk state. The SMBH accretes at 2% of the Bondi rate ( M ̇ ≃ 2.4 × 10 − 3 M ⊙ yr − 1 for M87*) and launches twin jets at η = 150% efficiency. These jets are powerful enough (P jets ≃ 2 × 1044 erg s−1) to escape along the SMBH spin axis and end the short-lived intermittent jet state, whose transient nature can account for the rarity of XRGs.

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“…Recently, we presented the first results from the analysis of the deeper Chandra observations (Cycle 21 LP proposal, 420 ks, PI: Gitti; plus the previous ∼50 ks observations), focused on the cavity system only (Ubertosi et al 2021). We found that the N-S radio lobes also have inflated X-ray cavities at the same projected distances as the deep E-W ones.…”

Section: The Galaxy Cluster Rbs 797mentioning

confidence: 73%

“…Background files were obtained from blank sky event files, normalized to the 9-12 keV count rate of the observations. More details on the Chandra data reduction procedures can be found in Ubertosi et al (2021).…”

Section: X-ray: Chandramentioning

confidence: 99%

“…The top panel of Figure 1 shows the background-subtracted, exposure-corrected Chandra image. In the bottom panels, we show the original image filtered with the Gaussian gradient magnitude (GGM) filter (Sanders et al 2016) with a 2″ filter and the residual Chandra image (originally presented in Ubertosi et al 2021, obtained by subtracting a 2D double βmodel from the Chandra image). In the inner ∼50 kpc, there are the four equidistant X-ray cavities already discussed in Ubertosi et al (2021), best visible in the residual image (right panel).…”

Section: Shock Fronts In the Icmmentioning

confidence: 99%

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Multiple Shock Fronts in RBS 797: The Chandra Window on Shock Heating in Galaxy Clusters

Ubertosi

¹

,

Gitti

²

,

Brighenti

³

et al. 2023

ApJ

Self Cite

10

2

0

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Using ∼427 ks of Chandra observations, we present a study of shock heating and intracluster medium (ICM) cooling in the galaxy cluster RBS 797. We discover three nested pairs of weak shocks at roughly 50, 80, and 130 kpc from the center. The total energy associated with the shocks is ∼6 × 1061 erg, with the central active galactic nucleus (AGN) driving a pair of weak shocks every 20–30 Myr with a power P sh ≈ 1046 erg s−1. Based on its morphology and age (∼30 Myr), the inner cocoon shock is associated with the four equidistant X-ray cavities previously discovered. From the thermodynamic analysis of the inner 30 kpc, we find evidence for ICM condensation into colder gas between and behind the X-ray cavities. The total AGN mechanical power (cavities and shocks) of 3.4 × 1046 erg s−1 can balance the ICM radiative losses, estimated as L cool = 2.3 × 1045 erg s−1. By building plots of P cav versus L cool, P shock versus L cool, and P tot versus L cool for RBS 797 and 14 other galaxy clusters, galaxy groups, and elliptical galaxies where both cavities and shocks are detected, we verify that the most powerful outbursts are found in the strongest cooling systems. Ultimately, we observe that the mechanical power of the AGN exceeds the gas radiative losses by a factor that is different for FR I and FR II radio galaxies, being less than a few tens for FR Is (as RBS 797) and more than roughly 100 for FR IIs.

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“…There will always be such time evolution to the extents of the multiphase gas as well as the cavities that will wash out correlations, which are difficult to account for in observations (e.g., Qiu et al 2021;Fabian et al 2022). To complicate matters further, some systems have multiple generations of X-ray cavities (e.g., Perseus: Fabian et al 2006;Hydra: Wise et al 2007;NGC5813: Randall et al 2011), sometimes even perpendicular to each other (e.g., RBS797: Ubertosi et al 2021), which makes it difficult to connect a specific outburst to the extent of cooling seen at longer wavelengths. Conversely, the fact that the star-forming filaments in some systems extend beyond any detected X-ray cavities (e.g., Phoenix, A1795) does not necessarily rule out bubble uplift, but it is impossible to say without deeper data, and even that may not help when older bubbles are projected along the line of sight.…”

Section: 〈R〉 Hα[oii] Versus Bubblesmentioning

confidence: 99%

Testing the Limits of AGN Feedback and the Onset of Thermal Instability in the Most Rapidly Star-forming Brightest Cluster Galaxies

Calzadilla

¹

,

McDonald

²

,

Donahue

³

et al. 2022

ApJ

Self Cite

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We present new, deep, narrow- and broadband Hubble Space Telescope observations of seven of the most star-forming brightest cluster galaxies (BCGs). Continuum-subtracted [OII] maps reveal the detailed, complex structure of warm (T ∼ 104 K) ionized gas filaments in these BCGs, allowing us to measure spatially resolved star formation rates (SFRs) of ∼60–600 M ⊙yr−1. We compare the SFRs in these systems and others from the literature to their intracluster medium cooling rates ( M ̇ cool ), measured from archival Chandra X-ray data, finding a best-fit relation of log ( SFR ) = ( 1.66 ± 0.17 ) log ( M ̇ cool ) + (−3.22 ± 0.38) with an intrinsic scatter of 0.39 ± 0.09 dex. This steeper-than-unity slope implies an increasingly efficient conversion of hot (T ∼ 107 K) gas into young stars with increasing M ̇ cool , or conversely a gradual decrease in the effectiveness of AGN feedback in the strongest cool cores. We also seek to understand the physical extent of these multiphase filaments that we observe in cluster cores. We show, for the first time, that the average extent of the multiphase gas is always smaller than the radii at which the cooling time reaches 1 Gyr, the t cool/t ff profile flattens, and that X-ray cavities are observed. This implies a close connection between the multiphase filaments, the thermodynamics of the cooling core, and the dynamics of X-ray bubbles. Interestingly, we find a one-to-one correlation between the average extent of cool multiphase filaments and the radius at which the cooling time reaches 0.5 Gyr, which may be indicative of a universal condensation timescale in cluster cores.

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The Deepest Chandra View of RBS 797: Evidence for Two Pairs of Equidistant X-ray Cavities

Cited by 21 publications

References 60 publications

Bridging the Bondi and Event Horizon Scales: 3D GRMHD Simulations Reveal X-shaped Radio Galaxy Morphology

Bridging the Bondi and Event Horizon Scales: 3D GRMHD Simulations Reveal X-shaped Radio Galaxy Morphology

Multiple Shock Fronts in RBS 797: The Chandra Window on Shock Heating in Galaxy Clusters

Testing the Limits of AGN Feedback and the Onset of Thermal Instability in the Most Rapidly Star-forming Brightest Cluster Galaxies

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