arXiv subjects

A. Gvozdenko

Publications and source records attributed to A. Gvozdenko.

3 recordsLinked to original sources

arXiv2026

Globular cluster Observations for Luminosity-dispersion Distances (GOLD): Project description and velocity catalogue

We introduce and describe the Globular cluster Observations for Luminosity-Dispersion distances (GOLD) project, which has the principal aim of determining independent distances based on the globular cluster (GC) absolute magnitude-velocity dispersion ($M_V - σ$) relation calibrated with Milky Way GCs with Gaia distances. The project comprises observations of GCs in 19 early- and late-type galaxies taken with FLAMES/GIRAFFE on ESO's Very Large Telescope. So far, 17 galaxies have been observed. The spectra cover the wavelength range 8483-9000 AA, including the calcium triplet region at a spectral resolution of $R\sim18,000$. The spectra provide line-of-sight velocities with typical uncertainties of $Δv = 1-2$ km s$^{-1}$. Using primarily velocities to separate extragalactic sources from foreground stars, we present here our initial sample of 1062 GCs and 101 ultra-compact dwarf galaxies (UCDs). For more than 650 of these objects we present the first velocity measurement. We discuss the available photometry and size measurements, and show that our velocities are in good agreement with previous studies. Our velocity catalogues are made publicly available. Beyond the principal aim of obtaining precision distances, additional science to be explored with these data includes host galaxy halo dynamics and clustering analysis, mass-to light ratios of GCs and UCDs in the sample, the stellar initial mass function and black hole occupation fraction of the GCs, and chemical abundances from high-dispersion spectra.

astro-ph.GA↗

arXiv2026

Extragalactic archaeology through high-resolution integrated-light spectroscopy of globular clusters

We propose to radically expand the use of extragalactic globular clusters as tools for extragalactic archaeology. We propose a large-scale spectroscopic facility to obtain high spectral resolution (R $\sim$ 20,000) spectroscopy for a significant fraction of all globular clusters in the nearby Universe. This will facilitate the reconstruction of galaxy assembly histories via chemical tagging, trace dark matter haloes, and measure extragalactic distances.

astro-ph.GA↗

arXiv2025

Revisiting the globular clusters of NGC1052-DF2

The ultra-diffuse galaxy (UDG) NGC1052-DF2 has captured the interest of astronomers ever since the low velocity dispersion measured from ten globular clusters (GCs) suggested a low dark matter fraction. Also, its GC system was found to be unusually bright, with a GC luminosity function peak at least one magnitude brighter than expected for a galaxy at a distance of 20 Mpc. In this work we present an updated view of the GC system of NGC1052-DF2. We analysed archival MUSE data of NGC1052-DF2 to confirm the membership of four additional GCs based on their radial velocities, thereby raising the number of spectroscopically confirmed GCs to 16. We measured the ages and metallicities of 11 individual GCs, finding them to be old ($> 9$ Gyr) and with a range of metallicities from [M/H] = $-0.7$ to $-1.8$ dex. The majority of GCs are found to be more metal-poor than the host galaxy, with some metal-rich GCs sharing the metallicity of the host ([M/H] = $-$1.09$^{+0.09}_{-0.07}$ dex). The host galaxy shows a flat age and metallicity gradient out to 1 $R_\text{e}$. Using a distance measurement based on the internal GC velocity dispersions ($D = 16.2$ Mpc), we derived photometric GC masses and find that the peak of the GC mass function compares well with that of the Milky Way. From updated GC velocities, we estimated the GC system velocity dispersion of NGC1052-DF2 with a simple kinematic model and find $σ_\text{GCS} = 14.86^{+3.89}_{-2.83}$ km s$^{-1}$. However, this value is reduced to $σ_\text{GCS} = 8.63^{+2.88}_{-2.14}$ km s$^{-1}$ when the GC that has the highest relative velocity based on a low S/N spectrum is considered an interloper. We discuss the possible origin of NGC1502-DF2, taking the lower distance, spread in GC metallicities, flat stellar population profiles, and dynamical mass estimate into consideration.

astro-ph.GA↗