Anke Ardern-Arentsen

@ankeaa.bsky.social

264 Followers 131 Following

🇳🇱 Galactic Archaeologist 🔭✨, postdoc at the Institute of Astronomy in Cambridge. Married to @zachary-ardern.bsky.social, evolution-explorer

Picture of a TV screen showing the Sun through an H-alpha filter. Some nice solar prominences can be seen on the upper right
A view of Nice city and the Mediterranean sea, framed by a window inside the Observatory library. There are clouds in the sky and some raindrops on the window, but the view is amazing.
The image shows three spectra from top to bottom (metal-rich, very metal-poor and carbon-enhanced very metal-poor, respectively), with each wavelength visualised by a coloured vertical line. The axis goes from ~380-700 nanometers. The metal-rich star has more and stronger dark lines than the metal-poor star, corresponding to absorption features. The carbon-enhanced metal-poor star has massive absorption bands, corresponding to molecular carbon absorption.
All 21 choir members that participated in the concert, smiling and doing some spontaneous movements for the photo. We are wearing black & white and red scarves. The photo is taken in the front of Great St Mary’s Church.
This is a photo of the CD based spectroscope using a paper folding mechanism to focus the light, which has a Gaia logo
Gaia colour absolute-magnitude diagram for very metal-poor RGB stars, where carbon-rich stars (identified using Gaia XP, see the paper) are colour-coded by their carbon abundance. Carbon-rich stars follow a redder RGB sequence than carbon-normal stars.
Several small boats floating on a blue sea near a beach and green foresty hills
the top part of the figure shows three synthetic spectra with different carbon abundances, and the bottom part shows Gaia XP low-resolution spectra for carbon-normal and carbon-rich stars. It is clear that carbon-rich stars can be identified from these spectra
Energy versus angular momentum for 4 metallicity groups in PIGS. Most of the stars have very high energies, consistent with them being very bound to the inner Galaxy. They get less bound for lower metallicities. Two comparison lines are also shown, showing that most stars in PIGS are below the "Heracles line" and almost all stars are below the "Aurora line". This is just a comparison and does not mean that these are accreted/in-situ respectively.
Azimuthal velocity as a function of metallicity for the PIGS sample. The velocity decreases with decreasing metallicity, but flattens below [Fe/H] < -2.0 and remains above zero.
The fraction of stars in the PIGS sample that has their orbits confined within a given distance (10, 5 or 3.5 kpc) from the Galactic centre as a function of metallicity. It decreases with decreasing metallicity, and flattens for [Fe/H] < -2.0.
PIGS survey logo
From high metallicity (bottom right) to low metallicity (top left), a transition can be seen in the vR (velocity in the radial direction) versus vphi (velocity in direction of rotation) space - a disc component is clearly present at high metallicity, but disappears in the lowest metallicity bins, where only halo-like stars are left.
Photo of my wedding ring on our wedding day, with my hand on my husbands shoulder. Our faces aren’t visible, and there is a hint of my bouquet.