First author: Hannah Übler
We present JWST/NIRSpec Integral Field Spectrograph rest-frame optical data of the compact $z=5.55$ galaxy GS_3073. Its prominent broad components in several hydrogen and helium lines (while absent in the forbidden lines), and the detection of a large equivalent width of He II $\lambda4686$, EW(He II) $\sim20$ Angstrom, unambiguously identify it as an active galactic nucleus (AGN). We measure a gas-phase metallicity of $Z_{\rm gas}/Z_\odot\sim0.21^{+0.08}{-0.04}$, lower than what has been inferred for both more luminous AGN at similar redshift and lower redshift AGN.
First author: S. Ranasinghe
We present an revised table of 390 Galactic radio supernova remnants (SNRs) and their basic parameters. Statistical analyses are performed on SNR diameters, ages, spectral indices, Galactic heights and spherical symmetries. Furthermore, the accuracy of distances estimated using the $\Sigma$-D relation is examined. The arithmetic mean of the Galactic SNR diameters is $30.5$ pc with standard error $1.7$ pc and standard deviation $25.4$ pc. The geometric mean and geometric standard deviation factor of Galactic SNR diameters is $21.
First author: Aurel Schneider
The 21-cm power spectrum of reionization is a promising probe for cosmology and fundamental physics. Exploiting this new observable, however, requires fast predictors capable of efficiently scanning the very large parameter space of cosmological and astrophysical uncertainties. In this paper, we introduce the halo model of reionization (HMreio), a new analytical tool that combines the halo model of the cosmic dawn with the excursion-set bubble model for reionization, assuming an empirical correction factor to deal with overlapping ionization bubbles.
First author: V. Heesen
Context. The existence of magnetic fields in the circumgalactic medium (CGM) is largely unconstrained. Their detection is important as magnetic fields can have a significant impact on the evolution of the CGM and, in turn, the fields can serve as tracers for dynamical processes in the CGM. Aims. With Faraday rotation of polarised background sources, we aim to detect a possible excess of the rotation measure in the surrounding area of nearby galaxies.
Jun Yang
Dwarf galaxies are characterised by a very low luminosity and low mass. Because of significant accretion and ejection activity of massive black holes, some dwarf galaxies also host low-luminosity active galactic nuclei (AGNs). In a few dwarf AGNs, very long baseline interferometry (VLBI) observations have found faint non-thermal radio emission. SDSS J090613.77+561015.2 is a dwarf AGN owning an intermediate-mass black hole (IMBH) with a mass of $M_{BH} = 3.
First author: Jun Yang
Dwarf galaxies are characterised by a very low luminosity and low mass. Because of significant accretion and ejection activity of massive black holes, some dwarf galaxies also host low-luminosity active galactic nuclei (AGNs). In a few dwarf AGNs, very long baseline interferometry (VLBI) observations have found faint non-thermal radio emission. SDSS J090613.77+561015.2 is a dwarf AGN owning an intermediate-mass black hole (IMBH) with a mass of $M_{BH} = 3.
First author: Mahmoud AlHallak
Single field inflationary models are investigated within Palatini quadratic gravity represented by $R+\alpha R^2$ along with a non-minimal coupling of the form $f(\phi) R$ between the inflaton field $\phi$ and the gravity. The treatment is performed in the Einstein frame, where the minimal coupling to gravity is recovered through conformal transformation. We consider various limits of the model with different inflationary scenarios characterized as canonical slow-roll inflation in the limit $\alpha \dot{\phi}^2\ll (1+f(\phi)) $, constant-roll k-inflation for $\alpha \ll 1$, and slow-roll K-inflation for$ \alpha \gg 1$ .
Stephanie Monty
The assembly history of the Milky Way (MW) is a rapidly evolving subject, with numerous small accretion events and at least one major merger proposed in the MW's history. Accreted alongside these dwarf galaxies are globular clusters (GCs), which act as spatially coherent remnants of these past events. Using high precision differential abundance measurements from our recently published study, we investigate the likelihood that the MW clusters NGC 362 and NGC 288 are galactic siblings, accreted as part of the Gaia-Sausage-Enceladus (GSE) merger.
First author: Dayi Li
We propose a novel set of Poisson Cluster Process models to detect Ultra-Diffuse Galaxies (UDGs), a recently-discovered class of galaxies that are challenging to detect and are of substantial interests in modern astrophysics. We construct an improved spatial birth-death-move MCMC algorithm to make inferences about the locations of these otherwise un-observable galaxies. Our novel models significantly out-perform existing approaches based on the Log-Gaussian Cox Process; the novel marked point process we propose can also improve the detection performance for UDGs in noisy environments.
First author: Darius McAdam
The distribution of the spin directions of spiral galaxies in the Sloan Digital Sky Survey has been a topic of debate in the past two decades, with conflicting conclusions reported even in cases where the same data was used. Here we follow one of the previous experiments by applying the SpArcFiRe algorithm to annotate the spin directions in original dataset of Galaxy Zoo 1. The annotation of the galaxy spin directions is done after a first step of selecting the spiral galaxies in three different manners: manual analysis by Galaxy Zoo classifications, by a model-driven computer analysis, and with no selection of spiral galaxies.
