2022(year)

Non-local contribution from small scales in galaxy-galaxy lensing: Comparison of mitigation schemes

First author: J. Prat Recent cosmological analyses with large-scale structure and weak lensing measurements, usually referred to as 3$\times$2pt, had to discard a lot of signal-to-noise from small scales due to our inability to precisely model non-linearities and baryonic effects. Galaxy-galaxy lensing, or the position-shear correlation between lens and source galaxies, is one of the three two-point correlation functions that are included in such analyses, usually estimated with the mean tangential shear.

Numerical analyses of M31 dark matter profiles

Kuantay Boshkayev We reproduce the rotation curve of the Andromeda galaxy (M31) by taking into account its bulge, disk, and halo components, considering the last one to contain the major part of dark matter mass. Hence, our prescription is to split the galactic bulge into two components, namely, the inner and main bulges, respectively. Both bulges are thus modeled by exponential density profiles since we underline that the widely accepted de Vaucouleurs law fails to reproduce the whole galactic bulge rotation curve.

On the application of dimensionality reduction and clustering algorithms for the classification of kinematic morphologies of galaxies

First author: M. S. Rosito The morphological classification of galaxies is considered a relevant issue and can be approached from different points of view. The increasing growth in the size and accuracy of astronomical data sets brings with it the need for the use of automatic methods to perform these classifications. The aim of this work is to propose and evaluate a method for automatic unsupervised classification of kinematic morphologies of galaxies that yields a meaningful clustering and captures the variations of the fundamental properties of galaxies.

On the bright-end of the UV luminosity functions of galaxies at $z \sim 0.6-1.2$

First author: M. Sharma We derive the Ultra-Violet (UV) luminosity function (LF) of star forming galaxies falling in the redshift range $z = 0.6 - 1.2$, in the rest-frame far-UV (1500 {\AA}) wavelength. For this work we are in particular interested in the bright end of the UV LF in this redshift range. The data from \textit{XMM-Newton} Optical Monitor (XMM-OM), near-ultraviolet (1600-4000 {\AA}) observations over 1.5 deg\textsuperscript{2} of the COSMOS field are employed for this purpose.

On the observability and identification of Population III galaxies with JWST

James A. A. Trussler We utilise theoretical models of Population III stellar+nebular spectra to investigate the prospects of observing and accurately identifying Population III galaxies with JWST using both deep imaging and spectroscopy. We investigate a series of different colour cuts, finding that a combination of NIRCam and MIRI photometry through the F444W-F560W, F560W-F770W colours offers the most robust identifier of potential $z=8$ Pop III candidates. We calculate that NIRCam will have to reach $\sim$ 28.

PANDORA project: photo-nuclear reactions below A=60

A. Tamii, L. Pellegri Photo-nuclear reactions of light nuclei below a mass of $A=60$ are studied experimentally and theoretically by the PANDORA (Photo-Absorption of Nuclei and Decay Observation for Reactions in Astrophysics) project. Two experimental methods, virtual-photon excitation by proton scattering and real-photo absorption by a high-brilliance gamma-ray beam produced by laser Compton scattering, will be applied to measure the photo-absorption cross sections and the decay branching ratio of each decay channel as a function of the photon energy.

Peekaboo: the extremely metal poor dwarf galaxy HIPASS J1131-31

I. D. Karachentsev The <span class="search-hit mathjax">dwarf</span> irregular <span class="search-hit mathjax">galaxy</span> HIPASS J1131-31 was discovered as a source of HI emission at low redshift in such close proximity of a bright star that we call it Peekaboo. The <span class="search-hit mathjax">galaxy</span> resolves into stars in images with Hubble Space Telescope, leading to a distance estimate of 6.8+-0.7 Mpc. Spectral optical observations with the Southern African Large Telescope reveal HIPASS J1131-31 to be one of the most extremely metal-poor <span class="search-hit mathjax">galaxies</span> known with the gas-phase oxygen abundance 12+log(O/H) = 6.

Peekaboo: the extremely metal poor dwarf galaxy HIPASS J1131-31

First author: I. D. Karachentsev The dwarf irregular galaxy HIPASS J1131-31 was discovered as a source of HI emission at low redshift in such close proximity of a bright star that we call it Peekaboo. The galaxy resolves into stars in images with Hubble Space Telescope, leading to a distance estimate of 6.8+-0.7 Mpc. Spectral optical observations with the Southern African Large Telescope reveal HIPASS J1131-31 to be one of the most extremely metal-poor galaxies known with the gas-phase oxygen abundance 12+log(O/H) = 6.

Photometric and Structural Parameters of Newly Discovered Nuclear Star Clusters in Local Volume Galaxies

Nils Hoyer We use high-resolution Hubble Space Telescope imaging data of <span class="search-hit mathjax">dwarf</span> <span class="search-hit mathjax">galaxies</span> in the Local Volume ($\lesssim 11$ Mpc) to parameterise 19 newly discovered nuclear star clusters (NSCs). Most of the clusters have stellar masses of $M_{\star}^{nsc} \lesssim 10^6$ M$_{\odot}$ and compare to Galactic globular clusters in terms of ellipticity, effective radius, stellar mass, and surface density. The clusters are modelled with a Sérsic profile and their surface brightness evaluated at the effective radius reveals a tight positive correlation to the host <span class="search-hit mathjax">galaxy</span> stellar mass.

Photometric and Structural Parameters of Newly Discovered Nuclear Star Clusters in Local Volume Galaxies

First author: Nils Hoyer We use high-resolution Hubble Space Telescope imaging data of dwarf galaxies in the Local Volume ($\lesssim 11$ Mpc) to parameterise 19 newly discovered nuclear star clusters (NSCs). Most of the clusters have stellar masses of $M_{\star}^{nsc} \lesssim 10^6$ M${\odot}$ and compare to Galactic globular clusters in terms of ellipticity, effective radius, stellar mass, and surface density. The clusters are modelled with a S'ersic profile and their surface brightness evaluated at the effective radius reveals a tight positive correlation to the host galaxy stellar mass.