2022(year)

COSMOS2020: The Galaxy Stellar Mass Function: On the assembly and star formation cessation of galaxies at $0.2\lt z \leq 7.5$

First author: J. R. Weaver How galaxies form, assemble, and cease their star-formation is a central question within the modern landscape of galaxy evolution studies. These processes are indelibly imprinted on the galaxy stellar mass function (SMF). We present constraints on the shape and evolution of the SMF, the quiescent galaxy fraction, and the cosmic stellar mass density across 90% of the history of the Universe from $z=7.5\rightarrow0.2$ via the COSMOS survey.

Differences between the globular cluster systems of the Virgo and Fornax Galaxy Clusters

J. Dabringhausen It is well known that Globular cluster systems are different among galaxies. Here we test to which degree these differences remain on the scale of galaxy clusters by comparing the globular clusters (GCs) in optical surveys of the Virgo galaxy cluster (ACSVCS) and the Fornax galaxy cluster (ACSFCS) in Kolmogorov-Smirnoff Tests. Both surveys were obtained with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope, and contain thousands of GCs in dozens of galaxies each.

Discovery and properties of the earliest galaxies with confirmed distances

First author: B. E. Robertson Surveys with James Webb Space Telescope (JWST) have discovered candidate galaxies in the first 400 Myr of cosmic time. The properties of these distant galaxies provide initial conditions for understanding early galaxy formation and cosmic reionisation. Preliminary indications have suggested these candidate galaxies may be more massive and abundant than previously thought. However, without spectroscopic confirmation of their distances to constrain their intrinsic brightnesses, their inferred properties remain uncertain.

Discovery of a double sequence of blue straggler stars in the core-collapsed globular cluster NGC 6256

Mario Cadelano We used a combination of high-resolution optical images acquired with the Hubble Space Telescope and near-IR wide-field data to investigate the stellar density profile and the population of blue straggler star (BSS) in the Galactic globular cluster NGC6256, with the aim of probing its current stage of internal dynamical evolution. We found that the inner stellar density profile significantly deviates from a King model while is well reproduced by a steep cusp with a power-law slope alpha=-0.

Discovery of a new Local Group Dwarf Galaxy Candidate in UNIONS: Boötes V

Simon E. T. Smith We present the discovery of Boötes V, a new ultra-faint dwarf galaxy candidate. This satellite is detected as a resolved overdensity of stars during an ongoing search for new Local Group dwarf galaxy candidates in the UNIONS photometric dataset. It has a physical half-light radius of 26.9$^{+7.5}_{-5.4}$ pc, a $V$-band magnitude of $-$4.5 $\pm$ 0.4 mag, and resides at a heliocentric distance of approximately 100 kpc.

Distinguishing Dark Matter Cusps from Cores using Globular Clusters

Shaunak Modak Globular Clusters (GCs) provide valuable insight into the properties of their host galaxies’ dark matter halos. Using N-body simulations incorporating semianalytic dynamical friction and GC-GC merger prescriptions, we study the evolution of GC radial distributions and mass functions in cuspy and cored dark matter halos. Modeling the dynamics of the GC-rich system in the dwarf galaxy UGC7369, we find that friction-induced inspiral and subsequent mergers of massive GCs can naturally and robustly explain the mass segregation of the GCs and the existence of a nuclear star cluster (NSC).

DUVET: Spatially Resolved Observations of Star Formation Regulation via Galactic Outflows in a Starbursting Disk Galaxy

Bronwyn Reichardt Chu We compare 500~pc scale, resolved observations of ionised and molecular gas for the $z\sim0.02$ starbursting disk galaxy IRAS08339+6517, using measurements from KCWI and NOEMA. We explore the relationship of the star formation driven ionised gas outflows with colocated galaxy properties. We find a roughly linear relationship between the outflow mass flux ($\dotΣ_{\rm out}$) and star formation rate surface density ($Σ_{\rm SFR}$), $\dotΣ_{\rm out}\proptoΣ_{\rm SFR}^{1.06\pm0.10}$, and a strong correlation between $\dotΣ_{\rm out}$ and the gas depletion time, such that $\dotΣ_{\rm out} \propto t_{dep}^{-1.

Dwarf AGNs from Variability for the Origins of Seeds (DAVOS): Optical Variability of Broad-line Dwarf AGNs from the Zwicky Transient Facility

First author: Z. Franklin Wang We study the optical variability of a sample of candidate low-mass (dwarf ang Seyfert) active galactic nuclei (AGNs) using Zwicky Transient Facility g-band light curves. Our sample is compiled from broad-line AGNs in dwarf galaxies reported in the literature with single-epoch virial black hole (BH) masses in the range $M_{\rm{BH}} \sim 10^{4}$–$10^{8}\ M_{\odot}$. We measure the characteristic ``damping’’ timescale of the optical variability $\tau_{\rm{DRW}}$, beyond which the power spectral density flattens, of a final sample of 79 candidate low-mass AGNs with high-quality light curves.

Early-type Dwarf Galaxies in the Local Universe. Evidence of Ex-situ Growth

Sanjaya Paudel We report the discovery of a rare early-type <span class="search-hit mathjax">dwarf</span> <span class="search-hit mathjax">galaxy</span> (dE), SDSS J125651.47+163024.2 (hereafter dE1256), possessing a tidal feature that was likely built up by accretion of an even smaller <span class="search-hit mathjax">dwarf</span> <span class="search-hit mathjax">galaxy</span>. dE1256 is located in a nearly isolated environment, at the outskirt of the Virgo cluster. A detailed morphological examination reveals that the accreted stellar population is mainly deposited in the outer part of dE1256, where the tidal tail is most prominent.

Early-type Dwarf Galaxies in the Local Universe. Evidence of Ex-situ Growth

First author: Sanjaya Paudel We report the discovery of a rare early-type dwarf galaxy (dE), SDSS J125651.47+163024.2 (hereafter dE1256), possessing a tidal feature that was likely built up by accretion of an even smaller dwarf galaxy. dE1256 is located in a nearly isolated environment, at the outskirt of the Virgo cluster. A detailed morphological examination reveals that the accreted stellar population is mainly deposited in the outer part of dE1256, where the tidal tail is most prominent.