galaxies

First author: Stephen M. Wilkins JWST has now made it possible to probe the rest-frame optical line emission of high-redshift galaxies extending to z~9, and potentially beyond. To aid in the interpretation of these emerging constraints, in this work we explore predictions for $[OIII]$ emission in high-redshift galaxies using the First Light and Reionisation Epoch Simulations (FLARES). We produce predictions for the $[OIII]$ luminosity function, its correlation with the UV luminosity, and the distribution of equivalent widths (EWs).

First author: Jeremy S. Sanders High-spectral resolution observations of clusters of galaxies are a powerful tool to understand the physical processes taking place in these massive objects. Their hot multi-million-degree X-ray emitting cluster atmospheres, containing most of the baryons in these systems, are enriched to around 1/3 of the solar metallicity. Therefore, cluster spectra host a variety of spectral lines, in particular, the Fe-L complex around 1 keV typically emitted from cooler systems and Fe-K at 6.

First author: Hao He We employ the Feedback In Realistic Environments (FIRE-2) physics model to study how the properties of giant molecular clouds (GMCs) evolve during galaxy mergers. We conduct a pixel-by-pixel analysis of molecular gas properties in both the simulated control galaxies and galaxy major mergers. The simulated GMC-pixels in the control galaxies follow a similar trend in a diagram of velocity dispersion ($\sigma_v$) versus gas surface density ($\Sigma_{\mathrm{mol}}$) to the one observed in local spiral galaxies in the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) survey.

First author: F. Stanley We present the results of a survey of CO(1-0) emission in 14 infrared luminous dusty star forming galaxies (DSFGs) at 2 < z < 4 with the NSF’s Karl G. Jansky Very Large Array. All sources are detected in CO(1-0), with an ~1arcsec angular resolution. Seven sources show extended and complex structure. We measure CO luminosities of $({\mu})L’{CO(1-0)}=0.4-2.9x10^{11}$ K km s$^{-1}$ pc$^2$, and molecular gas masses of (${\mu}$)M${H2}$ = 1.

First author: Federico Sestito Five stars in the extreme outskirts (from $\sim5$ to $\sim12$ elliptical half-light radii, r$_h$) of the Ursa Minor (UMi) dwarf galaxy have been identified as potential new members using a Bayesian algorithm applied to \textit{Gaia} EDR3 data. These targets were observed with the GRACES spectrograph, resulting in precise radial velocities and metallicities that confirm their association with UMi. For the brightest and outermost star (Target~1, at $\sim12$ r$_h$), the chemical abundances of $\alpha$- (Mg, Ca, Ti), odd-Z (Na, K, Sc), Fe-peak (Fe, Ni, Cr), and neutron-capture process (Ba) elements have also been determined.

First author: Joseph Whittingham The role of magnetic fields in galaxy evolution is still an unsolved question in astrophysics. We have previously shown that magnetic fields play a crucial role in major mergers between disc galaxies; in hydrodynamic simulations of such mergers, the Auriga model produces compact remnants with a distinctive bar and ring morphology. In contrast, in magnetohydrodynamic (MHD) simulations, remnants form radially-extended discs with prominent spiral arm structure.

First author: Jérémy Fensch While interstellar gas is known to be supersonically turbulent, the injection processes of this turbulence are still unclear. Many studies suggest a dominant role of gravitational instabilities. However, their effect on galaxy morphology and large-scale dynamics vary across cosmic times, in particular due to the evolution of the gas fraction of galaxies. In this paper, we propose numerical simulations to follow the isothermal turbulent cascade of purely gravitationally-driven turbulence from its injection scale down to 0.

First author: Benjamin Beauchesne We present a new method to simultaneously/self-consistently model the mass distribution of galaxy clusters that combines constraints from strong lensing features, X-ray emission and galaxy kinematics measurements. We are able to successfully decompose clusters into their collisionless and collisional mass components thanks to the X-ray surface brightness, as well as using the dynamics of cluster members to obtain more accurate masses with the fundamental plane of elliptical galaxies.

First author: Kate Napier Tension between cosmic microwave background-based and distance ladder-based determinations of the Hubble constant H0 motivates pursuit of independent methods that are not subject to the same systematic effects. A promising alternative, proposed by Refsdal in 1964, relies on the inverse scaling of H0 with the delay between the arrival times of at least two images of a strongly-lensed variable source such as a quasar. To date, Refsdal’s method has mostly been applied to quasars lensed by individual galaxies rather than by galaxy clusters.

First author: Ramesh Mainali We present new observations of sixteen bright ($r=19-21$) gravitationally lensed galaxies at $z\simeq 1-3$ selected from the CASSOWARY survey. Included in our sample is the $z=1.42$ galaxy CSWA-141, one of the brightest known reionization-era analogs at high redshift (g=20.5), with a large sSFR (31.2 Gyr$^{-1}$) and an $[OIII]$+H$\beta$ equivalent width (EW${\rm{$[OIII]$+H\beta}}$=730~\r{A}) that is nearly identical to the average value expected at $z\simeq 7-8$. In this paper, we investigate the rest-frame UV nebular line emission in our sample with the goal of understanding the factors that regulate strong CIII]$ emission.