Big code paper dropped by our S. Rosswog introducing the Lagrangian Numerical Relativity code SPHINCS_BSSN. https://arxiv.org/pdf/2306.06226.pdf
Hamburg Observatory
@HambObs
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An institute of the University of Hamburg
Today on astro-ph: Evidence of Extended Dust and Feedback around z≈1 Quiescent Galaxies via Millimeter Observations
with our student K. Böckmann
https://arxiv.org/abs/2306.04760
with our student K. Böckmann
https://arxiv.org/abs/2306.04760
Evidence of Extended Dust and Feedback around z$\approx$1 Quiescent Galaxies via Millimeter Observations
We use public data from the South Pole Telescope (SPT) and Atacama Cosmology Telescope (ACT) to measure radial profiles of the thermal Sunyaev-Zel'dovich (tSZ) effect and dust emission around massive quiescent galaxies at $z\approx1.$ Using survey data from the Dark Energy Survey (DES) and Wide-Field infrared Survey Explorer (WISE), we selected $387,627$ quiescent galaxies within the ACT field, with a mean stellar $\log_{10}(M_{\star}/\rm{M_{\odot}})$ of $11.40$. A subset of $94,452$ galaxies, with a mean stellar $\log_{10}(M_{\star}/\rm{M_{\odot}})$ of $11.36,$ are also covered by SPT. In $0.5$ arcminute radial bins around these galaxies, we detect the tSZ profile at levels up to $11σ$, and dust profile up to $20σ.$ Both profiles are extended, and the dust profile slope at large radii is consistent with galaxy clustering. We analyze the thermal energy and dust mass versus stellar mass via integration within $R=2.0$ arcminute circular apertures and fit them with a forward-modeled power-law to correct for our photometric stellar mass uncertainty. At the mean log stellar mass of our overlap and wide-area samples, respectively, we extract thermal energies from the tSZ of $E_{\rm{pk}}=6.45_{-1.52}^{+1.67}\times10^{60}{\rm{ erg}}$ and $8.20_{-0.52}^{+0.52}\times10^{60}{\rm{ erg}},$ most consistent with moderate to high levels of active galactic nuclei feedback acting upon the circumgalactic medium. Dust masses at the mean log stellar mass are $M_{\rm{d,pk}}=6.23_{-0.67}^{+0.67}\times10^{8}\rm{ M_{\odot}}$ and $6.76_{-0.56}^{+0.56}\times10^{8}\rm{ M_{\odot}},$ and we find a greater than linear dust-to-stellar mass relation, which indicates that the more massive galaxies in our study retain more dust. Our work highlights current capabilities of stacking millimeter data around individual galaxies and potential for future use.
Today on astro-ph: A search for inter-cluster filaments with LOFAR and eROSITA led by D. Hoang et al. We did not find any emission from filaments but could find important constraints on B-fields.
Discovery should be within reach.
A search for inter-cluster filaments with LOFAR and eROSITA
Cosmological simulations predict the presence of warm hot thermal gas in the cosmic filaments that connect galaxy clusters. This gas is thought to constitute an important part of the missing baryons in the Universe. In addition to the thermal gas, cosmic filaments could contain a population of relativistic particles and magnetic fields. A detection of magnetic fields in filaments can constrain early magnetogenesis in the cosmos. So far, the resulting diffuse synchrotron emission has only been indirectly detected. We present our search for thermal and non-thermal diffuse emission from inter-cluster regions of 106 paired galaxy clusters by stacking the $0.6-2.3$~keV X-ray and 144~MHz radio data obtained with the eROSITA telescope on board the Spectrum-Roentgen-Gamma (SRG) observatory and LOw Frequency ARray (LOFAR), respectively. The stacked data do not show the presence of X-ray and radio diffuse emission in the inter-cluster regions. This could be due to the sensitivity of the data sets and/or the limited number of cluster pairs used in this study. Assuming a constant radio emissivity in the filaments, we find that the mean radio emissivity is not higher than $1.2\times10^{-44}\,{\rm erg \, s^{-1} \, cm^{-3} \, Hz^{-1}}$. Under equipartition conditions, our upper limit on the mean emissivity translates to an upper limit of $\sim75\,{\rm nG}$ for the mean magnetic field strength in the filaments, depending on the spectral index and the minimum energy cutoff. We discuss the constraint for the magnetic field strength in the context of the models for the formation of magnetic fields in cosmic filaments.
Just posted: Theoretical follow-up to our study of circumgalactic magnetic fields. led by R. Ramesh w. V. heesen and M. Brüggen.
Azimuthal Anisotropy of Magnetic Fields in the Circumgalactic Medium Driven by Galactic Feedback Processes
https://arxiv.org/abs/2305.11214
Azimuthal Anisotropy of Magnetic Fields in the Circumgalactic Medium Driven by Galactic Feedback Processes
https://arxiv.org/abs/2305.11214
Azimuthal Anisotropy of Magnetic Fields in the Circumgalactic Medium Driven by Galactic Feedback Processes
We use the TNG50 cosmological magnetohydrodynamical simulation of the IllustrisTNG project to show that magnetic fields in the circumgalactic medium (CGM) have significant angular structure. This azimuthal anisotropy at fixed distance is driven by galactic feedback processes that launch strong outflows into the halo, preferentially along the minor axes of galaxies. These feedback-driven outflows entrain strong magnetic fields from the interstellar medium, dragging fields originally amplified by small-scale dynamos into the CGM. At the virial radius, $z=0$ galaxies with M$_\star \sim 10^{10}\,\rm{M_\odot}$ show the strongest anisotropy ($\sim 0.35$ dex). This signal weakens with decreasing impact parameter, and is also present but weaker for lower mass as well as higher mass galaxies. Creating mock Faraday rotation measure (RM) sightlines through the simulated volume, we find that the angular RM trend is qualitatively consistent with recent observational measurements. We show that rich structure is present in the circumgalactic magnetic fields of galaxies. However, TNG50 predicts small RM amplitudes in the CGM that make detection difficult as a result of other contributions along the line of sight.
Today on the arxiv: A morphological analysis of the substructures in radio relics, led by D. Wittor.
Takaway point: The bulk of the radiative flux in relics comes from filamentary structures.
A morphological analysis of the substructures in radio relics
Recent observations of radio relics - diffuse radio emission in galaxy clusters - have revealed that these sources are not smooth but consist of structures in the form of threads and filaments. We investigate the origin of these filamentary structures and the role of projection effects. To this end, we have developed a tool that extracts the filamentary structures from background emission. Moreover, it is capable of studying both two-dimensional and three-dimensional objects. We apply our structure extractor to, both, observations and cosmological simulations of radio relics. Using Minkowski functionals, we determine the shape of the identified structures. In our 2D analysis, we find that the brightest structures in the observed and simulated maps are filaments. Our analysis of the 3D simulation data shows that radio relics do not consist of sheets but only of filaments and ribbons. Furthermore, we did not find any measurable projection effects that could hide any sheet-like structures in projection. We find that, both, the magnetic field and the shock front consist of filaments and ribbons that cause filamentary radio emission.
Big paper on the arxiv today, led by our V. Cuciti et al.
The Planck clusters in the LOFAR sky V. LoTSS-DR2: Mass - radio halo power correlation at low frequency
arxiv.org/abs/2305.04564
The Planck clusters in the LOFAR sky V. LoTSS-DR2: Mass - radio halo power correlation at low frequency
arxiv.org/abs/2305.04564
Italian dinner at the Observatory with my group. What a fun evening. Photo by Giulia Lusetti
Today on the arxiv: The eROSITA Final Equatorial-Depth Survey (eFEDS): A #machinelearning Approach to Infer Galaxy Cluster Masses from #eROSITA X-ray Images led by S. Krippendorf @esrabulbul
The eROSITA Final Equatorial-Depth Survey (eFEDS): A Machine Learning Approach to Infer Galaxy Cluster Masses from eROSITA X-ray Images
We develop a neural network based pipeline to estimate masses of galaxy clusters with a known redshift directly from photon information in X-rays. Our neural networks are trained using supervised learning on simulations of eROSITA observations, focusing in this paper on the Final Equatorial Depth Survey (eFEDS). We use convolutional neural networks which are modified to include additional information of the cluster, in particular its redshift. In contrast to existing work, we utilize simulations including background and point sources to develop a tool which is usable directly on observational eROSITA data for an extended mass range from group size halos to massive clusters with masses in between $10^{13}M_\odot<M<10^{15}M_\odot.$ Using this method, we are able to provide for the first time neural network mass estimation for the observed eFEDS cluster sample from Spectrum-Roentgen-Gamma/eROSITA observations and we find consistent performance with weak lensing calibrated masses. In this measurement, we do not use weak lensing information and we only use previous cluster mass information which was used to calibrate the cluster properties in the simulations. When compared to simulated data, we observe a reduced scatter with respect to luminosity and count-rate based scaling relations. We comment on the application for other upcoming eROSITA All-Sky Survey observations.
The Observatory’s P. Grete covered in this press release from Oak Ridge National Lab. Codes Cholla, HACC, and Parthenon are ready to launch the exascale era of computational astrophysics
https://www.olcf.ornl.gov/2023/04/26/simulating-a-more-detailed-universe-with-frontier/
