First author: W. J. Pearson
Galaxy mergers are hugely important in our current dark matter cosmology. These powerful events cause the disruption of the merging galaxies, pushing the gas, stars and dust of the galaxies resulting in changes to morphologies. This disruption can also cause more extreme events inside the galaxies: periods of extreme star formation rates and the rapid increase in active galactic nuclei activity. Hence, to better understand what goes on in these rare events, we need to be able to identify statistically large samples.
First author: R. A. Riffel
We present the hot molecular and warm ionised gas kinematics for 33 nearby ($0.001\lesssim z\lesssim0.056$) X-ray selected active galaxies using the H$2 2.1218 \mu$m and Br$\gamma$ emission lines observed in the K-band with the Gemini Near-Infrared Field Spectrograph (NIFS). The observations cover the inner 0.04$-$2 kpc of each AGN at spatial resolutions of 4$-$250 pc with a velocity resolution of $\sigma{\rm inst}\approx$20 ${\rm km s^{-1}}$.
First author: Iurii Babyk
The halo mass-temperature relation for a sample of 216 galaxy clusters, groups, and individual galaxies observed by $Chandra$ X-ray Observatory is presented. Using accurate spectral measurements of their hot atmospheres, we derive the $M-T$ relation for systems with temperatures ranging between 0.4-15.0 keV. We measure the total mass of clusters, groups, and galaxies at radius $R_{2500}$, finding that the $M_{2500} \propto T^{\alpha}$ relation follows a power-law with $\alpha$ = 1.
First author: Eric Giunchi
Exploiting broad- and narrow-band images of the \textit{Hubble Space Telescope} from near-UV to I-band restframe, we study the star-forming clumps of six galaxies of the GASP sample undergoing strong ram-pressure stripping (RPS). Clumps are detected in H$\alpha$ and near-UV, tracing star formation on different timescales. We consider clumps located in galaxy disks, in the stripped tails and those formed in stripped gas but still close to the disk, called extraplanar.
First author: Gopal-Krishna
A small subset of extragalactic double radio sources, termed HYMORS (HYbrid MOrpholgy Radio Sources), is distinguished by a very unusual, hybrid morphology in terms of the Fanaroff-Riley (FR) classification. In HYMORS, one radio lobe appears edge-darkened (FR I), while the other shows a well-defined emission peak near its outer edge (edge-brightened, FR II). Such sources are rare but critical for constraining the mechanism responsible for the FR dichotomy, a widely debated issue in extragalactic astrophysics.
First author: Ian Blackstone
Radiation pressure on dust is an important feedback process around star clusters and may eject gas from bright sub-regions in star-forming galaxies. The Eddington ratio has previously been constructed for galaxy-averaged observations, individual star clusters, and Galactic HII regions. Here we assess the role of radiation pressure in thousands of sub-regions across two local star-forming galaxies, NGC 6946 and NGC 5194. Using a model for the spectral energy distribution from stellar population synthesis and realistic dust grain scattering and absorption, we compute flux- and radiation pressure-mean opacities and population-averaged optical depth $\langle\tau_{\rm RP}\rangle$.
First author: Maria B. Stone
We explore the properties of galaxies in the proximity (within a $\sim$2 Mpc radius sphere) of Type I quasars at 0.1<z<0.35, to check whether and how an active galaxy influences the properties of its neighbors. We further compare these with the properties of neighbors around inactive galaxies of the same mass and redshift within the same volume of space, using the Galaxy and Mass Assembly (GAMA) spectroscopic survey.
First author: Dieu D. Nguyen
As the earliest relics of star formation episodes in the history of the Universe, the most massive galaxies are the key to our understanding of the evolution of the stellar population, cosmic structure, and SMBHs. However, the details of their formation histories remain uncertain. We address these problems by planning a large survey sample of ultramassive galaxies ($z\le0.3$, $|\delta+24^{\circ}|<45$\deg, $|b|>8$\deg), including 76% E, 17% S0, and 7% S brighter than $M_K\le-27$ mag (stellar mass $2\times10^{12}<M_\star<5\times10^{12}$ M$\odot$) with the HARMONI instrument on ELT.
First author: R. Calvi
There is controversy whether dusty starbursts selected at submillimeter wavelengths can trace galaxy overdensities. We perform the first systematic search for protoclusters around a homogeneously selected sample of 12 spectroscopically confirmed submillimeter galaxies (SMGs) at $z\sim1.2-5.3$ in the GOODS-N field. We applied the Poisson Probability Method (PPM) to search for Mpc scale overdensities around these SMGs using three photometric redshift catalogs. We detect galaxy overdensities for 11 out of the 12 SMGs ($92%\pm8$%), distributed over eight protoclusters.
First author: Fulvio Melia
The so-called impossibly early galaxy' problem, first identified via the Hubble Space Telescope's observation of galaxies at redshifts z > 10, appears to have been exacerbated by the more recent James Webb Space Telescope (JWST) discovery of galaxy candidates at even higher redshifts (z ~ 17) which, however, are yet to be confirmed spectroscopically. These candidates would have emerged only ~ 230 million years after the big bang in the context of LCDM, requiring a more rapid star formation in the earliest galaxies than appears to be permitted by simulations adopting the concordance model parameters.
