galaxies

First author: Syeda Lammim Ahad The diffuse light within galaxy groups and clusters provides valuable insight into the growth of massive cosmic structures. Groups are particularly interesting in this context, because they represent the link between galactic haloes and massive clusters. However, low surface brightness makes their diffuse light extremely challenging to detect individually. Stacking many groups is a promising alternative, but its physical interpretation is complicated by possible systematic variations of diffuse light profiles with other group properties.

First author: Behzad Tahmasebzadeh Barred structures are important in understanding galaxy evolution, but they were not included explicitly in most dynamical models for nearby galaxies due to their complicated morphological and kinematic properties. We modify the triaxial orbit-superposition Schwarzschild implementation by Van den Bosch et al. (2008) to include barred structures explicitly. The gravitational potential is a combination of a spherical dark matter halo and stellar mass; with the 3D stellar density distribution de-projected from the observed 2D image using a two-component de-projection method, including an axisymmetric disk and a triaxial barred bulge.

First author: Joseph DeRose Numerical simulations in cosmology require trade-offs between volume, resolution and run-time that limit the volume of the Universe that can be simulated, leading to sample variance in predictions of ensemble-average quantities such as the power spectrum or correlation function(s). Sample variance is particularly acute at large scales, which is also where analytic techniques can be highly reliable. This provides an opportunity to combine analytic and numerical techniques in a principled way to improve the dynamic range and reliability of predictions for clustering statistics.

First author: Jee-Ho Kim We analyze the stellar abundances of massive galaxies ($\log M_\ast/M_\odot>10.5$) at $z=2$ in the IllustrisTNG simulation with the goal of guiding the interpretation of current and future observations, particularly from the James Webb Space Telescope. We find that the effective size, $R_e$, of galaxies strongly affects the abundance measurements: both [Mg/H] and [Fe/H] are anti-correlated with $R_e$, while the relative abundance [Mg/Fe] slightly increases with $R_e$.

First author: M. Lopez-Corredoira A specific modification of Newtonian dynamics known as MOND has been shown to reproduce the dynamics of most astrophysical systems at different scales without invoking non-baryonic dark matter (DM). There is, however, a long-standing unsolved problem when MOND is applied to rich clusters of galaxies in the form of a deficit (by a factor around two) of predicted dynamical mass derived from the virial theorem with respect to observations.

First author: Jessica Sutter We present Herschel, ALMA, and MUSE observations of the molecular ring of Messier 104, also known as the Sombrero galaxy. These previously unpublished archival data shed new light on the content of the interstellar medium of M104. In particular, molecular hydrogen measured by CO emission and dust measured by far-infrared light are uniformly distributed along the ring. The ionized gas revealed by H$\alpha$ and $[CII]$ emission is distributed in knots along the ring.

First author: Lilit V. Barkhudaryan In this Letter, using classified 197 supernovae (SNe) Ia, we perform an analyses of their height distributions from the disc in edge-on spirals and investigate their light-curve (LC) decline rates $(\Delta m_{15})$. We demonstrate, for the first time, that 91T-, 91bg-like, and normal SNe Ia subclasses are distributed differently toward the plane of their host disc. The average height from the disc and its comparison with scales of thin/thick disc components gives a possibility to roughly estimate the SNe Ia progenitor ages: 91T-like events, being at the smallest heights, originate from relatively younger progenitors with ages of about several 100 Myr, 91bg-like SNe, having the highest distribution, arise from progenitors with significantly older ages $\sim 10$ Gyr, and normal SNe Ia, which distributed between those of the two others, are from progenitors of about one up to $\sim 10$ Gyr.

First author: David Garofalo Jet re-orientation associated with the time evolution of radio quasars explains the formation of X-shaped radio galaxies and their preference for isolated environments. But since X-shaped radio galaxies are generally not found in dense environments (e.g. groups/clusters), the jet re-orientation phenomenon for radio galaxies in groups and clusters has been ignored. We take a closer look at the re-orientation of FRI jets with respect to FRII jets, and find that it may constitute the as-yet unidentified trigger for star formation suppression in radio galaxies.

First author: Amira A. Tawfeek We present a study of barred galaxies in the cluster environment, exploiting a sample of galaxies drawn from the extended WIde-field Nearby Galaxy-cluster Survey (OmegaWINGS) that covers up to the outer regions of 32 local X-ray selected clusters. Barred galaxies are identified through a semi-automatic analysis of ellipticity and position angle profiles. We find, in agreement with previous studies, a strong co-dependence of the bar fraction with the galaxy stellar mass and morphological type, being maximum for massive late-type galaxies.

First author: C. L. Carilli We present simulations of the capabilities of the ngVLA to image at $\sim 0.75$ kpc resolution ($0.085"$), molecular line emission from star forming disk galaxies at high redshift. The results are compared to the current capabilities of ALMA. ALMA can detect the integrated emission, and determine the velocity gradient and size across the brighter emission regions of the galaxy. The ngVLA is a factor $\sim 6$ more sensitive at the adopted spatial and velocity resolution.