arXiv subjects

Jakob Dietl

Publications and source records attributed to Jakob Dietl.

5 recordsLinked to original sources

arXiv2026

The Quiescent Sloshing Core of Abell 496 with XRISM

Gas motions provide insight into the dynamical history and physical processes within galaxy clusters. We investigate the kinematics of the ICM in the core of A496, a nearby, X-ray bright, strong cool-core cluster, using high-resolution data from the Resolve micro-calorimeter on board XRISM. We compared our measurement with other Resolve cluster core measurements and further compared our results with simulations and multiwavelength observations. From an optical redshift analysis, we found that the BCG is at rest with respect to the systemic velocity of the cluster. Despite multiple previously detected cold fronts and harboring a weak central radio source, Resolve observation shows that the core of A496 is dynamically quiescent. The ICM is moving with respect to the BCG with a LOS bulk velocity of $v_{\rm bulk}=-69_{-20}^{+25}\,\mathrm{km\,s}^{-1}$. We measured a turbulent velocity of $σ_{\rm v}=78_{-16}^{+18}\,\mathrm{km\,s}^{-1}$, the lowest value reported by the instrument on a cluster core to date. This value is in good agreement with the velocity dispersion of the H$α$ filament in the core, which may indicate condensation of ICM in the wake of the radio bubble. Assuming isotropic turbulence, the ICM turbulent velocity corresponds to a subsonic 3D Mach number of $0.15_{-0.03}^{+0.04}$ and a non-thermal pressure fraction of $1.2_{-0.5}^{+0.6}\,\%$. The mechanical AGN feedback from the recent activity of the central radio source is estimated to contribute about 7-9% to the ICM heating. The 1D LOS bulk velocity from the SLOW constrained Universe simulation is consistent with the measured value, suggesting that AGN feedback has a negligible contribution. The A496 SLOW turbulent velocity, as in other reported Resolve--simulation comparisons, is higher, but remains within $1.5σ$ uncertainty. A496 may represent one of the most quiescent sloshing cores observed so far.

astro-ph.CO↗

arXiv2026

The SRG/eROSITA All-Sky Survey: A comprehensive X-ray analysis of the Hydra I galaxy cluster

The Hydra I galaxy cluster (Abell 1060) is a nearby example of a low-temperature cluster that exhibits intermediate cool core and non-cool core properties. Our aims are to extend the characterization of the intracluster medium (ICM) properties at least until $R_{200}$ and study the correlation between the X-ray emission and non-thermal emission within $R=0.15$$R_{500}$, and optical/IR galaxy distribution beyond $R_{200}$. We used data from the first four SRG/eROSITA All-Sky Surveys and an archival Chandra observation to image the X-ray emission from Abell 1060. We also used multiwavelength data from TGSS (radio), 2MASS (IR), and NED (optical) to investigate the non-thermal emission, 2D galaxy distribution, and its redshift evolution, respectively. The surface brightness and spectral analyses are also extended until 3$R_{200}$ and $R_{200}$, respectively, following a detailed cosmic X-ray background (CXB) analysis. Our fully corrected eROSITA image showcases a relaxed ICM morphology within $R_{500}$. We detected two surface brightness discontinuities near the central galaxy NGC~3311 that spatially coincide with diffuse radio emission along the line of sight. Furthermore, we detected two soft X-ray excesses with high spatial correlation with the 2D optical galaxy distribution beyond $R_{200}$. In particular, the excess in the north has a significance of $3.9σ$ above the local CXB level. This suggests that Abell 1060's outskirts are actively accreting baryons. We also estimated the average ICM temperature and metallicity of $\langle k_\mathrm{B}T \rangle=2.51\substack{+0.21\\-0.21}\thinspace$ keV and $\langle Z\rangle=0.19\substack{+0.10\\-0.10}\thinspace Z_\odot$, respectively, from the 0.2-0.5$R_{500}$ annulus. Overall, the temperature profile is broadly consistent with the average temperature profiles from hydrodynamical simulation and Suzaku between 0.43$R_{500}$ and $R_{500}$.

astro-ph.CO↗

arXiv2026

Bulk and turbulent gas motions in the interacting galaxy cluster Abell 3395 South observed with XRISM

We investigate the gas motions in the core region of the Abell~3395 South subcluster (A3395S) using high-resolution X-ray spectroscopy with XRISM/Resolve. By analyzing the Fe~XXV He$α$ emission line, we directly measure the line-of-sight bulk and turbulent velocities of the intracluster medium. We find that the one-dimensional turbulent velocity is low, at the level of $124\pm21~{\rm km\,s^{-1}}$, while a significant line-of-sight bulk velocity of $263\pm23~{\rm km\,s^{-1}}$ is detected. The coexistence of low turbulence and finite bulk motion suggests that A3395S has not yet reached a dynamically relaxed state. These results are consistent with the non-detection of a radio halo in A3395S, implying that turbulent particle reacceleration is currently inefficient in the cluster core. This study demonstrates that high-resolution X-ray spectroscopy with XRISM provides a powerful means to directly constrain intracluster medium dynamics in merging galaxy clusters, and it provides a reference for future comparative studies of A3395N and A3391 within the same large-scale structure.

astro-ph.CO↗

arXiv2026

The life of central radio galaxies in clusters: AGN-ICM studies of eRASS1 clusters in the ASKAP fields

The mechanical feedback from the central AGNs can be crucial for balancing the radiative cooling of the intracluster medium at the cluster centre. We aim to understand the relationship between the power of AGN feedback and the cooling of gas in the centres of galaxy clusters by correlating the radio properties of the brightest cluster galaxies (BCGs) with the X-ray properties of their host clusters. We used catalogues from the first SRG/eROSITA All-Sky Survey (eRASS1) along with ASKAP radio data. In total, we identified 134 radio sources associated with BCGs of the 151 eRASS1 clusters located in the PS1, PS2, and SWAG-X ASKAP fields. Non-detections were treated as upper limits. We correlated BCG radio luminosity, largest linear size (LLS), and BCG offset with the integrated X-ray luminosity of their host clusters. To characterise cool cores (CCs) and non-cool cores (NCCs), we used the concentration parameter $c_{R_{500}}$ and combined it with the BCG offset to assess cluster dynamical state. We analysed the correlation between radio mechanical power and X-ray luminosity within the CC subsample. We observe a potential positive trend between LLS and BCG offset, suggesting an environmental effect on radio-source morphology. We find a weak trend where more luminous central radio galaxies are found in clusters with higher X-ray luminosity. Within the CC subsample, there is a positive but highly scattered relationship between the mechanical luminosity of AGN jets and the X-ray cooling luminosity. This finding is supported by bootstrap resampling and flux-flux analyses. The correlation indicates that AGN feedback is ineffective in high-luminosity (high-mass) clusters. At a cooling luminosity of $L_{\mathrm{X},~r<R_\mathrm{cool}}\approx 5.50\times10^{43}$ erg/s, on average, AGN feedback appears to contribute only about 13%-22% of the energy needed to offset the radiative losses in the ICM.

astro-ph.CO↗

arXiv2022

PLANETAMOS, A Physics Show Musical (Phyusical)

We present a physics show musical with live physics experiments and live performed songs with live orchestral accompaniment. The musical was first put on stage in German at the Physikalische Institut, University of Bonn, on the 24th of March, 2019. Here we present the original German script as well as an English translation, including a translation of the songs. We also give brief descriptions of all the experiments employed, with photos as well as how we present the experiments. The musical tells the story of a couple, Life and Death, nicknamed Vita and Mortis, who want to buy a planet where they can settle down and raise a family. They arrive at the store Planetamos, run by the manager Luna Callisto and the scientist Jupi Mercury. The latter two present to Vita and Mortis what is required for life on a planet, as well as all of the extra features for sale, to make it that very special place for their family. Through Vita and Mortis the audience learns about the physical requirements for life on a planet orbiting a star. The show involves 14 live physics experiments. The four actors sing 7 songs, which are to well-known tunes with new lyrics, in German. During the show the singers are accompanied by a small live orchestra, consisting of a flute, an oboe, a piano, a violin, a cello, a harp and percussion. The show was developed by the University of Bonn physics students, who have all been very active in the University of Bonn Physics Show (Physikshow der Universitaet Bonn) the past few years. To the best of our knowledge this is the first physics show musical with live experiments and live song and orchestra.

physics.pop-ph↗