Gone after one orbit: How cluster environments quench galaxies

The effect of galactic orbits on a galaxy's internal evolution within a galaxy cluster environment has been the focus of heated debate in recent years. To understand this connection, we use both the $(0.5 \,$Gpc)$^3$ and the Gpc$^3$ boxes from the cosmological hydrodynamical simulation set Magneticum Pathfinder. We investigate the velocity-anisotropy, phase space, and the orbital evolution of up to $\sim 5 \cdot 10^{5}$ resolved satellite galaxies within our sample of 6776 clusters with $M_{\mathrm{vir}} > 10^{14} \, \mathrm{M_{\odot}}$ at low redshift, which we also trace back in time. In agreement with observations, we find that star-forming satellite galaxies inside galaxy clusters are characterised by more radially dominated orbits, independent of cluster mass. Furthermore, the vast majority of star-forming satellite galaxies stop forming stars during their first passage. We find a strong dichotomy both in line-of-sight and radial phase space between star-forming and quiescent galaxies, in line with observations. The tracking of individual orbits shows that the star-formation of almost all satellite galaxies drops to zero within $1 \, \mathrm{Gyr}$ after in-fall. Satellite galaxies that are able to remain star-forming longer are characterised by tangential orbits and high stellar mass. All this indicates that in galaxy clusters the dominant quenching mechanism is ram-pressure stripping.Comment: 22 pages, 16 figures, accepted by MNRA

Fokussier- und Abbildungseigenschaften von Solenoiden

In der LEBT-Sektion der Frankfurter Neutronenquelle am Stern-Gerlach-Zentrum (FRANZ) befinden sich zur transversalen Fokussierung des Ionenstrahls vier Solenoide. Die ersten beiden dienen dem Einschuss in das ExB-Choppersystem, die letzten beiden dem Einschuss in die erste Beschleunigerstruktur, den Radiofrequenzquadrupol (RFQ). In numerischen Transportsimulationen konnte gezeigt werden, dass insbesondere der erste Solenoid einen hohen Füllgrad aufweisen wird, was zu Strahlaberrationen und damit zu einer unerwünschten Erhöhung der Strahlemittanz führen kann. Um diesen Effekt zu untersuchen, wurden die Fokussier- und Abbildungseigenschaften des ersten FRANZ-Solenoides analysiert. Analytische Rechnung unter Verwendung der Twissparametertransformation wurden durchgeführt, numerische Simulationen mit einem idealisiertem und einem realistischem Magnetfeldverlauf gemacht und 2 Messaufbauten mit einer Volumenquelle, dem Solenoid und einer Schlitz-Gitter-Emittanzmessanlage realisiert, um gemessene mit analytischen und numerischen Daten vergleichen zu können. Die Parameter, die ausgewertet und verglichen wurden, sind die Lage der Emittanzellipse, die Emittanz im x-x'-Phasenraum und die normierten vierten Momente (Wölbung) im Ortsraum.In the Frankfurt neuron source at the Stern-Gerlach-Zentrum (FRANZ) low energy beam transport section four solenoid lenses are located for the transversal focussing of the ion beam. The first two solenoids are used to focus the beam into the ExB chopper system, the second two solenoids are used for the beam matching into the first accelerator structure, the radio-frequency quadrupole (RFQ). Numerical simulations showed a high solenoid filling degree which can lead to beam aberrations and an increased beam emittance. To investigate these aberrations the focus and mapping characteristics of the first solenoid have been analysed. Analytical calculations have been done using the twissparameter transformation. Simulations with idealised and realistic magnetical fields have been carried out and two experimental setups with a volume ion source, the solenoid and a slid-grid emittance measurement device have been built up to compare measured results with analytical and numerical ones. The parameter which have been evaluated and compared are the emittance ellipse position, the emittance in the x-x'-phasespace and the kurtosis in position space

Rise and fall of post-starburst galaxies in Magneticum Pathfinder

Post-starburst galaxies (PSBs) belong to a short-lived transition population between star-forming (SF) and quiescent galaxies. Deciphering their heavily discussed evolutionary pathways is paramount to understanding galaxy evolution. We aim to determine the dominant mechanisms governing PSB evolution in both the field and in galaxy clusters. Using the cosmological hydrodynamical simulation suite Magneticum Pathfinder, we identify 647 PSBs with $z \sim 0$ stellar mass $M_* \geq 5 \cdot 10^{10} \, \mathrm{M_{\odot}}$. We track their galactic evolution, merger history, and black hole activity over a time-span of 3.6Gyr. Additionally, we study cluster PSBs identified at different redshifts and cluster masses. Independent of environment and redshift, we find that PSBs, like SF galaxies, have frequent mergers. At z=0, 89% of PSBs have experienced mergers and 65% had at least one major merger within the last 2.5Gyr, leading to strong star formation episodes. In fact, 23% of z=0 PSBs were rejuvenated during their starburst. Following the mergers, field PSBs are generally shutdown via a strong increase in AGN feedback (power output $P_{AGN,PSB} \geq 10^{56}\,$erg/Myr). We find agreement with observations for both stellar mass functions and z = 0.9 line-of-sight phase space distributions of PSBs in galaxy clusters. Finally, we find that $z \lesssim 0.5$ cluster PSBs are predominantly infalling, especially in high mass clusters and show no signs of enhanced AGN activity. Thus, we conclude that the majority of cluster PSBs are shutdown via an environmental quenching mechanism such as ram-pressure stripping, while field PSBs are mainly quenched by AGN feedback.Comment: 28 pages, 15 figures, accepted by MNRA

Does the Fornax dwarf spheroidal have a central cusp or core?

The dark matter dominated Fornax dwarf spheroidal has five globular clusters orbiting at ~1 kpc from its centre. In a cuspy CDM halo the globulars would sink to the centre from their current positions within a few Gyrs, presenting a puzzle as to why they survive undigested at the present epoch. We show that a solution to this timing problem is to adopt a cored dark matter halo. We use numerical simulations and analytic calculations to show that, under these conditions, the sinking time becomes many Hubble times; the globulars effectively stall at the dark matter core radius. We conclude that the Fornax dwarf spheroidal has a shallow inner density profile with a core radius constrained by the observed positions of its globular clusters. If the phase space density of the core is primordial then it implies a warm dark matter particle and gives an upper limit to its mass of ~0.5 keV, consistent with that required to significantly alleviate the substructure problem.Comment: 6 pages, 5 figures, accepted for publication in MNRAS, high resolution simulations include

ECMO for COVID-19 patients in Europe and Israel

Since March 15th, 2020, 177 centres from Europe and Israel have joined the study, routinely reporting on the ECMO support they provide to COVID-19 patients. The mean annual number of cases treated with ECMO in the participating centres before the pandemic (2019) was 55. The number of COVID-19 patients has increased rapidly each week reaching 1531 treated patients as of September 14th. The greatest number of cases has been reported from France (n = 385), UK (n = 193), Germany (n = 176), Spain (n = 166), and Italy (n = 136) .The mean age of treated patients was 52.6 years (range 16–80), 79% were male. The ECMO configuration used was VV in 91% of cases, VA in 5% and other in 4%. The mean PaO2 before ECMO implantation was 65 mmHg. The mean duration of ECMO support thus far has been 18 days and the mean ICU length of stay of these patients was 33 days. As of the 14th September, overall 841 patients have been weaned from ECMO support, 601 died during ECMO support, 71 died after withdrawal of ECMO, 79 are still receiving ECMO support and for 10 patients status n.a. . Our preliminary data suggest that patients placed on ECMO with severe refractory respiratory or cardiac failure secondary to COVID-19 have a reasonable (55%) chance of survival. Further extensive data analysis is expected to provide invaluable information on the demographics, severity of illness, indications and different ECMO management strategies in these patients

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries