Re-detection and a Possible Time Variation of Soft X-ray Polarisation from the Crab

Kavli Affiliate: Renxin Xu | First 5 Authors: Hua Feng, Hong Li, Xiangyun Long, Ronaldo Bellazzini, Enrico Costa | Summary: The Crab nebula is so far the only celestial object with a statistically significant detection in soft x-ray polarimetry, a window that has not been explored in astronomy since the 1970s. However, soft x-ray polarimetry […]


Continue.. Re-detection and a Possible Time Variation of Soft X-ray Polarisation from the Crab

AI Poincaré: Machine Learning Conservation Laws from Trajectories

Kavli Affiliate: Max Tegmark | First 5 Authors: Ziming Liu, Max Tegmark, , , | Summary: We present AI Poincar’e, a machine learning algorithm for auto-discovering conserved quantities using trajectory data from unknown dynamical systems. We test it on five Hamiltonian systems, including the gravitational 3-body problem, and find that it discovers not only all […]


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Constraints on dark matter to dark radiation conversion in the late universe with DES-Y1 and external data

Kavli Affiliate: Aaron Roodman | First 5 Authors: Angela Chen, Dragan Huterer, Sujeong Lee, Agnès Ferté, Noah Weaverdyck | Summary: We study a phenomenological class of models where dark matter converts to dark radiation in the low redshift epoch. This class of models, dubbed DMDR, characterizes the evolution of comoving dark matter density with two […]


Continue.. Constraints on dark matter to dark radiation conversion in the late universe with DES-Y1 and external data

Spectral index of the Galactic foreground emission in the 50-87 MHz range

Kavli Affiliate: George Efstathiou | First 5 Authors: Marta Spinelli, Gianni Bernardi, Hugh Garsden, Lincoln J. Greehill, Anastasia Fialkov | Summary: Total-power radiometry with individual meter-wave antennas is a potentially effective way to study the Cosmic Dawn ($zsim20$) through measurement of sky brightness arising from the $21$~cm transition of neutral hydrogen, provided this can be […]


Continue.. Spectral index of the Galactic foreground emission in the 50-87 MHz range

On the Circular Polarisation of Repeating Fast Radio Bursts

Kavli Affiliate: Renxin Xu | First 5 Authors: Shi Dai, Jiguang Lu, Chen Wang, Weiyang Wang, Renxin Xu | Summary: Fast spinning (e.g., sub-second) neutron star with ultra-strong magnetic fields (or so-called magnetar) is one of the promising origins of repeating fast radio bursts (FRBs). Here we discuss circularly polarised emissions produced by propagation effects […]


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Evidence for violations of Weak Cosmic Censorship in black hole collisions in higher dimensions

Kavli Affiliate: Ulrich Sperhake | First 5 Authors: Tomas Andrade, Pau Figueras, Ulrich Sperhake, , | Summary: We study collisions of boosted rotating black holes in $D=6$ and 7 spacetime dimensions with a non-zero impact parameter. We find that there exists an open set of initial conditions such that the intermediate state of the collision […]


Continue.. Evidence for violations of Weak Cosmic Censorship in black hole collisions in higher dimensions

The Simons Observatory: gain, bandpass and polarization-angle calibration requirements for B-mode searches

Kavli Affiliate: Jeffrey McMahon | First 5 Authors: Maximilian H. Abitbol, David Alonso, Sara M. Simon, Jack Lashner, Kevin T. Crowley | Summary: We quantify the calibration requirements for systematic uncertainties for next-generation ground-based observatories targeting the large-angle $B$-mode polarization of the Cosmic Microwave Background, with a focus on the Simons Observatory (SO). We explore […]


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The black hole mass of the $z=2.805$ multiply imaged quasar SDSS J2222+2745 from velocity-resolved time lags of the CIV emission line

Kavli Affiliate: Michael Gladders | First 5 Authors: Peter R. Williams, Tommaso Treu, Håkon Dahle, Stefano Valenti, Louis Abramson | Summary: We present the first results of a 4.5 year monitoring campaign of the three bright images of multiply imaged $z=2.805$ quasar SDSS J2222+2745 using the Gemini North Multi-Object Spectrograph (GMOS-N) and the Nordic Optical […]


Continue.. The black hole mass of the $z=2.805$ multiply imaged quasar SDSS J2222+2745 from velocity-resolved time lags of the CIV emission line

Fluctuations can induce local nematic order and extensile stress in monolayers of motile cells

Kavli Affiliate: Boris I. Shraiman | First 5 Authors: Farzan Vafa, Mark J. Bowick, Boris I. Shraiman, M. Cristina Marchetti, | Summary: Recent experiments in various cell types have shown that two-dimensional tissues often display local nematic order, with evidence of extensile stresses manifest in the dynamics of topological defects. Using a mesoscopic model where […]


Continue.. Fluctuations can induce local nematic order and extensile stress in monolayers of motile cells