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The Andromeda Galaxy's Last Major Merger: Constraints from the survey of Planetary Nebulae
Souradeep Bhattacharya, Magda Arnaboldi, Ortwin Gerhard +7
The Andromeda galaxy (M 31) has experienced a tumultuous merger history as evidenced by the many substructures present in its inner halo. We use planetary nebulae (PNe) as chemodyn…
The survey of planetary nebulae in Andromeda (M31) VI. Kinematics of M31 inner-halo substructures and comparison with major-merger simulation predictions
Souradeep Bhattacharya, Magda Arnaboldi, Francois Hammer +4
M31 has experienced a recent tumultuous merger history as evidenced from the many substructures that are still present in its inner halo, particularly the G1-Clump, NE- and W- shel…
Peeking beneath the precision floor -- II. Probing the chemo-dynamical histories of the potential globular cluster siblings, NGC 288 and NGC 362
Stephanie Monty, David Yong, Davide Massari +8
The assembly history of the Milky Way (MW) is a rapidly evolving subject, with numerous small accretion events and at least one major merger proposed in the MW's history. Accreted…
There is No Place Like Home -- Finding Birth Radii of Stars in the Milky Way
Yuxi Lu, Ivan Minchev, Tobias Buck +6
Stars move away from their birthplaces over time via a process known as radial migration, which blurs chemo-kinematic relations used for reconstructing the Milky Way (MW) formation…
The survey of planetary nebulae in Andromeda (M 31) V. Chemical enrichment of the thin and thicker discs of Andromeda. Oxygen to argon abundance ratios for planetary nebulae and H II regions
Magda Arnaboldi, Souradeep Bhattacharya, Ortwin Gerhard +6
We use oxygen and argon abundances for planetary nebulae (PNe) with low internal extinction (progenitor ages of (>4.5 Gyr) and high extinction (progenitor ages <2.5 Gyr), as well a…
The GALAH Survey: A New Sample of Extremely Metal-Poor Stars Using A Machine Learning Classification Algorithm
Arvind C. N. Hughes, Lee R. Spitler, Daniel B. Zucker +21
Extremely Metal-Poor (EMP) stars provide a valuable probe of early chemical enrichment in the Milky Way. Here we leverage a large sample of high-resolution stellar sp…
The survey of planetary nebulae in Andromeda (M31). IV. Radial oxygen and argon abundance gradients of the thin and thicker disc
Souradeep Bhattacharya, Magda Arnaboldi, Nelson Caldwell +6
We obtain a magnitude-limited sample of Andromeda (M 31) disc PNe with chemical abundance estimated through the direct detection of the [OIII] 4363 line. Thi…
The halo of M105 and its group environment as traced by planetary nebula populations: II. Using kinematics of single stars to unveil the presence of intragroup light around the Leo I galaxies NGC 3384 and M105
J. Hartke, M. Arnaboldi, O. Gerhard +11
M105 is an early-type galaxy in the nearby Leo I group, the closest galaxy group to contain all galaxy types and therefore an excellent environment to explore the low-mass end of i…
The GALAH Survey: Chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and eDR3
Sven Buder, Karin Lind, Melissa K. Ness +27
Since the advent of astrometry, it is possible to identify massive accreted systems within the Galaxy through their unique dynamical signatures. One such system, -Saus…
The COMBS Survey -- III. The Chemodynamical Origins of Metal-Poor Bulge Stars
Madeline Lucey, Keith Hawkins, Melissa Ness +6
The characteristics of the stellar populations in the Galactic Bulge inform and constrain the Milky Way's formation and evolution. The metal-poor population is particularly importa…
A2A: 21,000 bulge stars from the ARGOS survey with stellar parameters on the APOGEE scale
S. M. Wylie, O. E. Gerhard, M. K. Ness +3
We use the data-driven method, The Cannon, to bring 21,000 stars from the ARGOS bulge survey, including 10,000 red clump stars, onto the parameter and abundance scales of the cross…
An [/Fe]-enhanced thick disk in a Milky Way Analogue
Nicholas Scott, Jesse van de Sande, Sanjib Sharma +5
The Milky Way disk consists of two prominent components - a thick, alpha-rich, low-metallicity component and a thin, metal-rich, low-alpha component. External galaxies have been sh…
The GALAH Survey: No chemical evidence of an extragalactic origin for the Nyx stream
Daniel B. Zucker, Jeffrey D. Simpson, Sarah L. Martell +20
The results from the ESA Gaia astrometric mission and deep photometric surveys have revolutionized our knowledge of the Milky Way. There are many ongoing efforts to search these da…
The survey of planetary nebulae in Andromeda (M31) III. Constraints from deep planetary nebula luminosity functions on the origin of the inner halo substructures in M31
Souradeep Bhattacharya, Magda Arnaboldi, Ortwin Gerhard +4
The Andromeda (M31) galaxy displays several substructures in its inner halo whose origin as remnants of accreted satellites or perturbations of the pre-existing disc are encoded in…
Combined APOGEE-GALAH stellar catalogues using the Cannon
Govind Nandakumar, Michael R. Hayden, Sanjib Sharma +21
APOGEE and GALAH are two high resolution multi-object spectroscopic surveys that provide fundamental stellar parameters and multiple elemental abundance estimates for about half a…
The GALAH Survey: Accreted stars also inhabit the Spite Plateau
Jeffrey D. Simpson, Sarah L. Martell, Sven Buder +22
The ESA Gaia astrometric mission has enabled the remarkable discovery that a large fraction of the stars near the Solar neighbourhood appear to be debris from a single in-falling s…
The GALAH+ Survey: Third Data Release
Sven Buder, Sanjib Sharma, Janez Kos +44
The ensemble of chemical element abundance measurements for stars, along with precision distances and orbit properties, provides high-dimensional data to study the evolution of the…
The COMBS Survey -- II. Distinguishing the Metal-Poor Bulge from the Halo Interlopers
Madeline Lucey, Keith Hawkins, Melissa Ness +9
The metal-poor stars in the bulge are important relics of the Milky Way's formation history, as simulations predict that they are some of the oldest stars in the Galaxy. In order t…
The halo of M105 and its group environment as traced by planetary nebula populations: I. Wide-field photometric survey of planetary nebulae in the Leo I group
J. Hartke, M. Arnaboldi, O. Gerhard +6
M105 (NGC 3379) is an early-type galaxy in the Leo I group. This group is the nearest group that contains all main galaxy types and can thus be used as a benchmark to study the pro…
A giant galaxy in the young Universe with a massive ring
Tiantian Yuan, Ahmed Elagali, Ivo Labbe +12
In the local (redshift z~0) Universe, collisional ring galaxies make up only ~0.01% of galaxies and are formed by head-on galactic collisions that trigger radially propagating dens…
Fundamental relations for the velocity dispersion of stars in the Milky Way
Sanjib Sharma, Michael R. Hayden, Joss Bland-Hawthorn +34
We explore the fundamental relations governing the radial and vertical velocity dispersions of stars in the Milky Way, from combined studies of complementary surveys including GALA…
The GALAH Survey: Chemically tagging the Fimbulthul stream to the globular cluster Centauri
Jeffrey D. Simpson, Sarah L. Martell, Gary Da Costa +17
Using kinematics from Gaia and the large elemental abundance space of the second data release of the GALAH survey, we identify two new members of the Fimbulthul stellar stream, and…
The survey of Planetary Nebulae in Andromeda (M31) II. Age-velocity dispersion relation in the disc from Planetary Nebulae
Souradeep Bhattacharya, Magda Arnaboldi, Nelson Caldwell +7
The age-velocity dispersion relation is an important tool to understand the evolution of the disc of the Andromeda galaxy (M31) in comparison with the Milky Way. We use Planetary N…
The K2-HERMES Survey: Age and Metallicity of the Thick Disc
Sanjib Sharma, Dennis Stello, Joss Bland-Hawthorn +34
Asteroseismology is a promising tool to study Galactic structure and evolution because it can probe the ages of stars. Earlier attempts comparing seismic data from the {\it Kepler}…