Kavli Affiliate: Xian Chen| Summary: Subgraph counting is a fundamental problem in graph analysis. Motivated by practical scenarios where graph analytics are performed on subgraphs induced by selected vertices — rather than on the entire graph — and by growing privacy concerns, we initiate the study of differentially private range subgraph counting (DPRSC). The goal […]
Kavli Affiliate: Gregory Herczeg | Summary:We present two-epoch JWST NIRSpec and MIRI observations of the young protostar EC 53 (V371 Ser), a periodically variable source with well-characterized quiescent and burst phases. The spectra in both epochs show absorption in the CO overtone ($sim$2.3 $μ$m) and fundamental ($sim$4.6 $μ$m) bands and the H$_2$O stretching ($sim$2.7 $μ$m) […]
Kavli Affiliate: Lijing Shao | Summary:We construct analytic solutions to the bumblebee gravity theory in static and spherically symmetric spacetimes, where the bumblebee vector field admits only a non-vanishing temporal component. In particular, we identify the parameter space that allows for asymptotically flat black hole solutions. We further investigate the thermodynamic properties of these black […]
Kavli Affiliate: Kohei Inayoshi | Summary:The James Webb Space Telescope (JWST) has uncovered a population of “little red dots” (LRDs) at $z gtrsim 4$, potentially representing early supermassive black holes embedded in dense gaseous envelopes. The recent discovery of the lensed LRD RXJ2211-RX1 reveals significant variability on rest-frame timescales of decades, which may be interpreted […]
Kavli Affiliate: Lijing Shao | Summary:Discovery and timing observations of a radio pulsar orbiting around Sagittarius A*, the supermassive black hole (SMBH) in our Galactic Centre (GC), will provide unprecedented opportunities of studying the SMBH spacetime, testing gravity theories, and probing the astrophysical environment in the GC. However, unknown mass distributions might cause timing residuals […]
Kavli Affiliate: Luis Ho | Summary:Balmer absorption lines are increasingly observed in the little red dots (LRDs) discovered by the James Webb Space Telescope, potentially tracing dense circumnuclear gas around rapidly accreting black holes. Motivated by this connection, we search for Balmer absorption using homogeneously analyzed spectra of a representative parent sample of 14,584 low-redshift […]
Kavli Affiliate: Luis Ho | Summary:We present a spectroscopic analysis of 14 little red dots (LRDs) at redshifts $2.2 < z < 6.7$ using NIRSpec/MSA prism and medium-resolution grating observations, aiming to constrain the nuclear gas structure through Balmer emission-line profiles, absorption features, relative line intensities, and continuum properties. We simultaneously decompose the broad, narrow, […]
Kavli Affiliate: Rainer Spurzem | Summary:We want to understand how the combined effect of initial substructure, primordial mass segregation, and primordial binaries affects the dynamical evolution of the cluster, and which one of these features is the most important to agree with observations. Methods. We use Nbody6++GPU to simulate the dynamics of star clusters with […]
Kavli Affiliate: Kohei Inayoshi | Summary:Little Red Dots (LRDs) are candidates for growing supermassive black holes newly discovered by the James Webb Space Telescope (JWST), characterized by compact rest-optical morphology, V-shaped spectra, and broad Hydrogen Balmer lines. While recently proposed BH-star/envelope models have made progress in explaining their optical features, their rest-UV emission, which is […]
Kavli Affiliate: Luis Ho | Summary:A significant puzzle in extragalactic astronomy is the scarcity of Little Red Dots (LRDs) at $z < 3$, compared to their higher abundance at earlier epochs. To understand this transition, we investigate the cosmic evolution of LRD environments. We measure the overdensity for LRDs and the general galaxy population at […]