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From Source Properties to Strong-Field Tests: a multipronged analysis of GW250114 with an effective one-body model for generic orbits
No full textWe present a detailed analysis of GW250114, the loudest gravitational-wave signal observed to date, using a waveform model capable of describing binary black holes in generic (eccentric and precessing) orbits. Our analysis builds on LIGO-Virgo-KAGRA (LVK)'s results, finding that the source is consistent at a probability of with the merger of two first-generation, nearly equal-mass, low-spin black holes, forming a remnant within the pair-instability mass gap. The signal's high signal-to-noise ratio () enables the detection of the subdominant multipoles, whose presence we confirm with higher evidence than previously reported by the LVK. Restricting the analysis even to post-peak data yields in favor of models including the mode, demonstrating that this contribution remains detectable well into the post-merger phase. We further perform three independent tests of general relativity, complementary to those performed by the LVK: a modified residual analysis confirms that our semi-analytical model fully describes the signal without detectable discrepancies; a subdominant mode test finds that the amplitude of the multipoles agrees with general-relativistic expectations; and a parameterised analysis of the plunge-merger-ringdown regime recovers the GR expectation within the 50\% credible region for the remnant mass and spin, and within the 90\% interval for the peak amplitude. Collectively, these results reinforce GW250114 as a landmark event for a precision test of gravity
Resonances in b-EMRIs: playing the black hole piano
No full textStellar-mass binaries evolving in the vicinity of supermassive black holes (SMBHs) may be common in the universe, either in active galactic nuclei or in other astrophysical environments. Here, we study in detail the resonant excitation of SMBH modes driven by a nearby stellar-mass binary. The resulting resonant energy fluxes vary with the orbital location and frequency of the binary, exhibiting a rich and complex structure. In particular, we find that the total energy flux radiated to infinity is maximized at a gravitational-wave frequency that is close to, but not exactly equal to, the real part of the corresponding quasinormal-mode frequency. Moreover, as the binary is moved farther away from the SMBH, this offset from the mode frequency becomes increasingly pronounced. In addition, for suitable orientations, the binary can effectively ``feed'' the light ring of the SMBH, selectively exciting particular oscillation modes. For rotating (Kerr) black holes, the mode spectrum is significantly more intricate; however, individual modes are also less strongly damped, leading to an enhanced - but more difficult to interpret - resonant response
Physical Effects of Gravitational Waves at Second Order
No full textThere is currently no rigorous definition of gravitational wave strain at second order in cosmological perturbation theory. The usual association of gravitational waves with transverse and traceless fluctuations of the metric on spatial hypersurfaces becomes ambiguous at second order, as it inherently depends on the spacetime slicing. While this poses no practical issues in linearized gravity, it presents a fundamental problem for secondary gravitational waves, especially notorious for gravitational waves induced by primordial fluctuations. We compute, for the first time, the physical effects of gravitational waves at second order, as measured by geodesic observers that emit and receive electromagnetic signals, thereby settling the debate on gauge ambiguities. We find that the measured gravitational wave strain coincides with the transverse-traceless components in the Newton gauge
"Unfassbares politisches Versagen": Interview
No full textSozialwissenschaftler Jens Beckert ist kein Umstürzler, aber er weiß: So wie jetzt können wir nicht weitermachen. Was für Folgen es hat, wenn wir den Klimawandel ignorieren
GRB 250702B: discovery of a gamma-ray burst from a black hole falling into a star
No full textGamma-ray bursts are the most luminous electromagnetic events in the Universe. Their prompt gamma-ray emission has typical durations between a fraction of a second and several minutes. A rare subset of these events have durations in excess of a thousand seconds, referred to as ultra-long gamma-ray bursts. Here, we report the discovery of the longest gamma-ray burst ever seen with a similar to 25 000 s gamma-ray duration, GRB 250702B, and characterize this event using data from four instruments in the InterPlanetary Network and the Monitor of All-sky X-ray Image. We find a hard spectrum, subsecond variability, and high total energy, which are only known to arise from ultrarelativistic jets powered by a rapidly spinning stellar-mass central engine. These properties and the extreme duration are together incompatible with all confirmed gamma-ray burst progenitors and nearly all models in the literature. This burst is naturally explained with the helium merger model, where a field binary ends when a black hole falls into a stripped star and proceeds to consume and explode it from within. Under this paradigm, GRB 250702B adds to the growing evidence that helium stars expand and that some ultra-long GRBs have similar evolutionary pathways as collapsars, stellar-mass gravitational wave sources, and potentially rare types of supernovae
In-Source Fragmentation Annotation in Sterol Mass Spectrometry Imaging
No full textSpatial biology has emerged as a pivotal area in many life science fields, with mass spectrometry imaging (MSI) becoming a cornerstone for molecular imaging. Among recent advancements to increase sensitivity, MALDI-2 technology has significantly expanded the molecular space accessible to MSI, increasing the ion yields of neutral metabolites, such as sterols. Sterols have recently taken center stage in numerous (patho-) physiological processes, including neurodegenerative diseases that have attracted significant scientific interest. However, in-source fragmentation (ISF) poses a substantial challenge for accurate biological interpretation of mass spectrometric data. In this study, we observed and investigated the ISF of cholesterol during MSI under MALDI and MALDI-2 conditions. Using a murine intervention model, we demonstrate how ISF can compromise the accuracy of biological interpretations, potentially leading to significant misinterpretations. Our study underscores the critical need to address ISF to ensure accurate molecular annotation, particularly through tandem mass spectrometry of in-source fragments. This is especially important when using MALDI-2 techniques. Furthermore, we introduce a high-resolution (5 μm) MSI technique, enabling the precise spatial analysis of cholesterol distribution
Chimpanzee groups achieve sustainable resource use in a common-pool resource dilemma
No full textCommon-pool resource dilemmas are group resource sustainability problems that are sensitive to over-extraction. While human strategies for overcoming common-pool resource dilemmas are well studied, the comparative evolutionary perspective has received little attention. Here, we compare resource management of chimpanzees (N = 15) grouped as dyads and quartets using an original experimental paradigm. The participants could use sticks to feed from a pool of yoghurt. The number of sticks equalled the number of players, and removing all of the sticks triggered resource collapse, thereby creating a social dilemma. Quartets were found to maintain the resource longer than dyads. Quartets’, but not dyads’, success was positively associated with social tolerance. Furthermore, quartets were more successful when the dominant ape acquired the relative lowest payoff. These results suggest that chimpanzees respond differently to cooperative sustainability problems depending on group size, with social tolerance playing an important role. The findings have implications for studying the evolution and diversity of hominid cooperation, in particular, highlighting that group size should be carefully considered in the design of non-human primate cooperation experiments
Crimes as status violations: conceptualising bipolar duties in criminal law
No full textIn this article, I would like to map out a path towards a relationalaccount of criminal wrongdoing that is as comprehensive as possible. Specifically, I argue thatcrimes affecting individuals involve the violation of intersubjective, bipolar duties. In this regard,I will directly address the prevailing understanding of crimes as impersonal wrongs, which Iconsider an obstacle to this project (1): I will demonstrate how it is conceptually feasible tomove beyond this ‘impersonal’ paradigm towards a ‘relational’ one (2). This shift is not merelytheoretical: bipolar duties and relational wrongs are, in fact, embedded in the way substantivecriminal law functions (3). Importantly, this does not imply a loss of the public dimension ofcrime, but rather its enrichment through an intersubjective dimension of wrongdoing (4). Finally,I will propose potential avenues for future research within the framework of a relationalparadigm in criminal law theory (5)
A watershed algorithm GUI for personalized fMRI-guided rTMS target
No full textPersonalized repetitive transcranial magnetic stimulation (rTMS) increasingly relies on resting-state functional magnetic resonance imaging (fMRI) to select stimulation sites, yet most pipelines depend on user-defined thresholds and atlas masks, which can shift individualized targets. We propose a watershed-based approach, implemented in a graphical user interface, that performs threshold-independent segmentation of functional images to support rTMS target localization. As a proof-of-concept, we focused on Alzheimer’s disease–related circuits within the default mode network, designating the posterior cingulate cortex (PCC) as the deep effective region and the inferior parietal lobule (IPL) as the superficial stimulation target. In a cohort of 21 healthy participants, quantitative comparison with a conventional threshold-based, mask-constrained peak strategy revealed high concordance for PCC peaks but a median spatial displacement of 6.0 mm (95 % CI: 0.0–12.7 mm) for IPL targets. Qualitative examples further illustrate that watershed segmentation reduces bias from neighboring functional clusters, truncation by atlas boundaries, and ambiguity among multiple local peaks. By decoupling target definition from user-chosen thresholds and packaging the method in an accessible toolbox, this framework offers a generalizable tool for individualized fMRI-guided rTMS