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Detection of Accretion Shelves Out to the Virial Radius of a Low-mass Galaxy with JWST (2024)
Journal Article
Conroy, C., Johnson, B. D., van Dokkum, P., Deason, A., Tacchella, S., Belli, S., …Emami, R. (2024). Detection of Accretion Shelves Out to the Virial Radius of a Low-mass Galaxy with JWST. The Astrophysical Journal, 968(2), Article 129. https://doi.org/10.3847/1538-4357/ad414a

We report the serendipitous discovery of an extended stellar halo surrounding the low-mass galaxy Ark 227 (M * = 5 × 109 M ⊙; d = 35 Mpc) in deep JWST NIRCam imaging from the Blue Jay Survey. The F200W–F444W color provides robust star–galaxy separati... Read More about Detection of Accretion Shelves Out to the Virial Radius of a Low-mass Galaxy with JWST.

The Hubble Space Telescope Survey of M31 Satellite Galaxies. II. The Star Formation Histories of Ultrafaint Dwarf Galaxies (2023)
Journal Article
Savino, A., Weisz, D. R., Skillman, E. D., Dolphin, A., Cole, A. A., Kallivayalil, N., …van der Marel, R. P. (2023). The Hubble Space Telescope Survey of M31 Satellite Galaxies. II. The Star Formation Histories of Ultrafaint Dwarf Galaxies. Astrophysical Journal, 956(2), Article 86. https://doi.org/10.3847/1538-4357/acf46f

We present the lifetime star formation histories (SFHs) for six ultrafaint dwarf (UFD; M V > − 7.0, 4.9

HALO7D. III. Chemical Abundances of Milky Way Halo Stars from Medium-resolution Spectra (2023)
Journal Article
McKinnon, K. A., Cunningham, E. C., Rockosi, C. M., Guhathakurta, P., Escala, I., Kirby, E. N., & Deason, A. J. (2023). HALO7D. III. Chemical Abundances of Milky Way Halo Stars from Medium-resolution Spectra. Astrophysical Journal, 951(1), Article 43. https://doi.org/10.3847/1538-4357/acd33d

The Halo Assembly in Lambda Cold Dark Matter: Observations in 7 Dimensions (HALO7D) survey measures the kinematics and chemical properties of stars in the Milky Way (MW) stellar halo to learn about the formation of our Galaxy. HALO7D consists of Keck... Read More about HALO7D. III. Chemical Abundances of Milky Way Halo Stars from Medium-resolution Spectra.

The progenitor galaxies of stellar haloes as ‘failed’ Milky Ways (2023)
Journal Article
Bose, S., & Deason, A. J. (2023). The progenitor galaxies of stellar haloes as ‘failed’ Milky Ways. Monthly Notices of the Royal Astronomical Society, 522(4), 5013-5021. https://doi.org/10.1093/mnras/stad1123

The stellar halo of the Milky Way records the history of its interactions with dwarf galaxies, whose subsequent destruction results in the formation of an extended stellar component. Recent works have suggested that galaxies with masses comparable to... Read More about The progenitor galaxies of stellar haloes as ‘failed’ Milky Ways.

Overview of the DESI Milky Way Survey (2023)
Journal Article
Cooper, A. P., Koposov, S. E., Allende Prieto, C., Manser, C. J., Kizhuprakkat, N., Myers, A. D., …Zou, H. (2023). Overview of the DESI Milky Way Survey. Astrophysical Journal, 947(1), Article 37. https://doi.org/10.3847/1538-4357/acb3c0

We describe the Milky Way Survey (MWS) that will be undertaken with the Dark Energy Spectroscopic Instrument (DESI) on the Mayall 4 m telescope at the Kitt Peak National Observatory. Over the next 5 yr DESI MWS will observe approximately seven millio... Read More about Overview of the DESI Milky Way Survey.

Constraining the shape of dark matter haloes with globular clusters and diffuse stellar light in the E-MOSAICS simulations (2023)
Journal Article
Reina-Campos, M., Trujillo-Gomez, S., Pfeffer, J. L., Sills, A., Deason, A. J., Crain, R. A., & Diederik Kruijssen, J. M. (2023). Constraining the shape of dark matter haloes with globular clusters and diffuse stellar light in the E-MOSAICS simulations. Monthly Notices of the Royal Astronomical Society, 521(4), 6368–6382. https://doi.org/10.1093/mnras/stad920

We explore how diffuse stellar light and globular clusters (GCs) can be used to trace the matter distribution of their host halo using an observational methodology. For this, we use 117 simulated dark matter (DM) haloes from the periodic volume of... Read More about Constraining the shape of dark matter haloes with globular clusters and diffuse stellar light in the E-MOSAICS simulations.

Unravelling the mass spectrum of destroyed dwarf galaxies with the metallicity distribution function (2023)
Journal Article
Deason, A. J., Koposov, S. E., Fattahi, A., & Grand, R. J. (2023). Unravelling the mass spectrum of destroyed dwarf galaxies with the metallicity distribution function. Monthly Notices of the Royal Astronomical Society, 520(4), 6091-6103. https://doi.org/10.1093/mnras/stad535

Accreted stellar populations are comprised of the remnants of destroyed galaxies, and often dominate the ‘stellar haloes’ of galaxies such as the Milky Way (MW). This ensemble of external contributors is a key indicator of the past assembly history o... Read More about Unravelling the mass spectrum of destroyed dwarf galaxies with the metallicity distribution function.

On the edge: the relation between stellar and dark matter haloes of Milky Way-mass galaxies (2023)
Journal Article
Genina, A., Deason, A., & Frenk, C. (2023). On the edge: the relation between stellar and dark matter haloes of Milky Way-mass galaxies. Monthly Notices of the Royal Astronomical Society, 520(3), 3767-3787. https://doi.org/10.1093/mnras/stad397

We investigate the build-up of the accreted stellar and dark matter haloes of Milky Way-like galaxies in APOSTLE suite of cosmological hydrodynamics simulations. We show that the stellar halo is made up primarily of stars stripped from a small number... Read More about On the edge: the relation between stellar and dark matter haloes of Milky Way-mass galaxies.

Energy wrinkles and phase-space folds of the last major merger (2022)
Journal Article
Belokurov, V., Vasiliev, E., Deason, A. J., Koposov, S. E., Fattahi, A., Dillamore, A. M., …Grand, R. J. (2023). Energy wrinkles and phase-space folds of the last major merger. Monthly Notices of the Royal Astronomical Society, 518(4), 6200-6215. https://doi.org/10.1093/mnras/stac3436

Relying on the dramatic increase in the number of stars with full 6D phase-space information provided by the Gaia Data Release 3, we resolve the distribution of the stellar halo around the Sun to uncover signatures of incomplete phase-mixing. We show... Read More about Energy wrinkles and phase-space folds of the last major merger.

Observing EAGLE galaxies with JWST: predictions for Milky Way progenitors and their building blocks (2022)
Journal Article
Evans, T. A., Fattahi, A., Deason, A. J., & Frenk, C. S. (2022). Observing EAGLE galaxies with JWST: predictions for Milky Way progenitors and their building blocks. Monthly Notices of the Royal Astronomical Society, 516(3), 3861-3877. https://doi.org/10.1093/mnras/stac2410

We present predictions, derived from the EAGLE ΛCDM cosmological hydrodynamical simulations, for the abundance and properties of galaxies expected to be detected at high redshift by the James Webb Space Telescope (JWST). We consider the galaxy popula... Read More about Observing EAGLE galaxies with JWST: predictions for Milky Way progenitors and their building blocks.

Structural Parameters and Possible Association of the Ultra-faint Dwarfs Pegasus III and Pisces II from Deep Hubble Space Telescope Photometry (2022)
Journal Article
Richstein, H., Patel, E., Kallivayalil, N., Simon, J. D., Zivick, P., Tollerud, E., …Sohn, S. T. (2022). Structural Parameters and Possible Association of the Ultra-faint Dwarfs Pegasus III and Pisces II from Deep Hubble Space Telescope Photometry. Astrophysical Journal, 933(2), Article 217. https://doi.org/10.3847/1538-4357/ac7226

We present deep Hubble Space Telescope (HST) photometry of the ultra-faint dwarf (UFD) galaxies Pegasus III (Peg III) and Pisces II (Psc II), two of the most distant satellites in the halo of the Milky Way (MW). We measure the structure of both galax... Read More about Structural Parameters and Possible Association of the Ultra-faint Dwarfs Pegasus III and Pisces II from Deep Hubble Space Telescope Photometry.

The chemo-dynamical groups of Galactic globular clusters (2022)
Journal Article
Callingham, T. M., Cautun, M., Deason, A. J., Frenk, C. S., Grand, R. J., & Marinacci, F. (2022). The chemo-dynamical groups of Galactic globular clusters. Monthly Notices of the Royal Astronomical Society, 513(3), 4107-4129. https://doi.org/10.1093/mnras/stac1145

We introduce a multicomponent chemo-dynamical method for splitting the Galactic population of globular clusters (GCs) into three distinct constituents: bulge, disc, and stellar halo. The latter is further decomposed into the individual large accretio... Read More about The chemo-dynamical groups of Galactic globular clusters.

Radial distributions of globular clusters trace their host dark matter halo: insights from the E-MOSAICS simulations (2022)
Journal Article
Reina-Campos, M., Trujillo-Gomez, S., Deason, A. J., Kruijssen, J. D., Pfeffer, J. L., Crain, R. A., …Hughes, M. E. (2022). Radial distributions of globular clusters trace their host dark matter halo: insights from the E-MOSAICS simulations. Monthly Notices of the Royal Astronomical Society, 513(3), 3925-3945. https://doi.org/10.1093/mnras/stac1126

Globular clusters (GCs) are bright objects that span a wide range of galactocentric distances, and can therefore probe the structure of dark matter (DM) haloes. In this work, we explore whether the projected number density radial profiles of GCs can... Read More about Radial distributions of globular clusters trace their host dark matter halo: insights from the E-MOSAICS simulations.

Fast, Slow, Early, Late: Quenching Massive Galaxies at z ∼ 0.8 (2022)
Journal Article
Tacchella, S., Conroy, C., Faber, S., Johnson, B. D., Leja, J., Barro, G., …Yesuf, H. M. (2022). Fast, Slow, Early, Late: Quenching Massive Galaxies at z ∼ 0.8. Astrophysical Journal, 926(2), Article 134. https://doi.org/10.3847/1538-4357/ac449b

We investigate the stellar populations for a sample of 161 massive, mainly quiescent galaxies at 〈zobs〉 = 0.8 with deep Keck/DEIMOS rest-frame optical spectroscopy (HALO7D survey). With the fully Bayesian framework Prospector, we simultaneously fit... Read More about Fast, Slow, Early, Late: Quenching Massive Galaxies at z ∼ 0.8.

Dwarf stellar haloes: a powerful probe of small-scale galaxy formation and the nature of dark matter (2021)
Journal Article
Deason, A. J., Bose, S., Fattahi, A., Amorisco, N. C., Hellwing, W., & Frenk, C. S. (2022). Dwarf stellar haloes: a powerful probe of small-scale galaxy formation and the nature of dark matter. Monthly Notices of the Royal Astronomical Society, 511(3), 4044-4059. https://doi.org/10.1093/mnras/stab3524

We use N-body cosmological simulations and empirical galaxy models to study the merger history of dwarf-mass galaxies (with Mhalo∼1010M⊙⁠). Our input galaxy models describe the stellar mass–halo mass relation, and the galaxy occupation fraction. The... Read More about Dwarf stellar haloes: a powerful probe of small-scale galaxy formation and the nature of dark matter.

Star Formation Histories of Ultra-faint Dwarf Galaxies: Environmental Differences between Magellanic and Non-Magellanic Satellites?* (2021)
Journal Article
Sacchi, E., Richstein, H., Kallivayalil, N., van der Marel, R., Libralato, M., Zivick, P., …Wetzel, A. (2021). Star Formation Histories of Ultra-faint Dwarf Galaxies: Environmental Differences between Magellanic and Non-Magellanic Satellites?*. Astrophysical Journal Letters, 920(1), Article L19. https://doi.org/10.3847/2041-8213/ac2aa3

We present the color–magnitude diagrams and star formation histories (SFHs) of seven ultra-faint dwarf galaxies: Horologium 1, Hydra 2, Phoenix 2, Reticulum 2, Sagittarius 2, Triangulum 2, and Tucana 2, derived from highprecision Hubble Space Telesco... Read More about Star Formation Histories of Ultra-faint Dwarf Galaxies: Environmental Differences between Magellanic and Non-Magellanic Satellites?*.

Discovery of a possible splashback feature in the intracluster light of MACS J1149.5+2223 (2021)
Journal Article
Gonzalez, A. H., George, T., Connor, T., Deason, A., Donahue, M., Montes, M., …Zaritsky, D. (2021). Discovery of a possible splashback feature in the intracluster light of MACS J1149.5+2223. Monthly Notices of the Royal Astronomical Society, 507(1), 963-970. https://doi.org/10.1093/mnras/stab2117

We present an analysis of the intracluster light (ICL) in the Frontier Field Cluster MACS J1149.5+2223 (z = 0.544), which combines new and archival Hubble WFC3/IR imaging to provide continuous radial coverage out to 2.8 Mpc from the brightest cluster... Read More about Discovery of a possible splashback feature in the intracluster light of MACS J1149.5+2223.

Detection of the LMC-induced sloshing of the Galactic halo (2021)
Journal Article
Erkal, D., Deason, A. J., Belokurov, V., Xue, X., Koposov, S. E., Bird, S. A., …Zhao, G. (2021). Detection of the LMC-induced sloshing of the Galactic halo. Monthly Notices of the Royal Astronomical Society, 506(2), 2677-2684. https://doi.org/10.1093/mnras/stab1828

A wealth of recent studies have shown that the LMC is likely massive, with a halo mass >1011M⊙. One consequence of having such a nearby and massive neighbour is that the inner Milky Way is expected to be accelerated with respect to our Galaxy’s outsk... Read More about Detection of the LMC-induced sloshing of the Galactic halo.

Space Telescope and Optical Reverberation Mapping Project. IX. Velocity–Delay Maps for Broad Emission Lines in NGC 5548 (2021)
Journal Article
Horne, K., Rosa, G. D., Peterson, B., Barth, A., Ely, J., Fausnaugh, M., …Zu, Y. (2021). Space Telescope and Optical Reverberation Mapping Project. IX. Velocity–Delay Maps for Broad Emission Lines in NGC 5548. Astrophysical Journal, 907(2), Article 76. https://doi.org/10.3847/1538-4357/abce60

In this contribution, we achieve the primary goal of the active galactic nucleus (AGN) STORM campaign by recovering velocity–delay maps for the prominent broad emission lines (Lyα, C iv, He ii, and Hβ) in the spectrum of NGC 5548. These are the most... Read More about Space Telescope and Optical Reverberation Mapping Project. IX. Velocity–Delay Maps for Broad Emission Lines in NGC 5548.

The mass of the Milky Way out to 100 kpc using halo stars (2020)
Journal Article
Deason, A. J., Erkal, D., Belokurov, V., Fattahi, A., Gómez, F. A., Grand, R. J., …Zhao, G. (2021). The mass of the Milky Way out to 100 kpc using halo stars. Monthly Notices of the Royal Astronomical Society, 501(4), 5964-5972. https://doi.org/10.1093/mnras/staa3984

We use a distribution function analysis to estimate the mass of the Milky Way (MW) out to 100 kpc using a large sample of halo stars. These stars are compiled from the literature, and the vast majority (⁠∼98 per cent⁠) have 6D phase-space information... Read More about The mass of the Milky Way out to 100 kpc using halo stars.

The twisted dark matter halo of the Milky Way (2020)
Journal Article
Shao, S., Cautun, M., Deason, A., & Frenk, C. S. (2021). The twisted dark matter halo of the Milky Way. Monthly Notices of the Royal Astronomical Society, 504(4), 6033-6048. https://doi.org/10.1093/mnras/staa3883

We analyse systems analogous to the Milky Way (MW) in the EAGLE cosmological hydrodynamics simulation in order to deduce the likely structure of the MW’s dark matter (DM) halo. We identify MW mass haloes in the simulation whose satellite galaxies hav... Read More about The twisted dark matter halo of the Milky Way.

Stellar splashback: the edge of the intracluster light (2020)
Journal Article
Deason, A. J., Oman, K. A., Fattahi, A., Schaller, M., Jauzac, M., Zhang, Y., …Evans, T. A. (2021). Stellar splashback: the edge of the intracluster light. Monthly Notices of the Royal Astronomical Society, 500(3), 4181-4192. https://doi.org/10.1093/mnras/staa3590

We examine the outskirts of galaxy clusters in the C-EAGLE simulations to quantify the ‘edges’ of the stellar and dark matter distribution. The radius of the steepest slope in the dark matter, commonly used as a proxy for the splashback radius, is lo... Read More about Stellar splashback: the edge of the intracluster light.

Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548 (2020)
Journal Article
Williams, P., Pancoast, A., Treu, T., Brewer, B., Peterson, B., Barth, A., …Zu, Y. (2020). Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548. Astrophysical Journal, 902(1), Article 74. https://doi.org/10.3847/1538-4357/abbad7

We present geometric and dynamical modeling of the broad line region (BLR) for the multi-wavelength reverberation mapping campaign focused on NGC 5548 in 2014. The data set includes photometric and spectroscopic monitoring in the optical and ultravio... Read More about Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548.

A tale of two populations: surviving and destroyed dwarf galaxies and the build-up of the Milky Way’s stellar halo (2020)
Journal Article
Fattahi, A., Deason, A. J., Frenk, C. S., Simpson, C. M., Gómez, F. A., Grand, R. J., …Pakmor, R. (2020). A tale of two populations: surviving and destroyed dwarf galaxies and the build-up of the Milky Way’s stellar halo. Monthly Notices of the Royal Astronomical Society, 497(4), 4459-4471. https://doi.org/10.1093/mnras/staa2221

We use magneto-hydrodynamical simulations of Milky Way-mass haloes from the Auriga project to investigate the properties of surviving and destroyed dwarf galaxies that are accreted by these haloes over cosmic time. We show that the combined luminosit... Read More about A tale of two populations: surviving and destroyed dwarf galaxies and the build-up of the Milky Way’s stellar halo.

How Unusual is the Milky Way’s Assembly History? (2020)
Journal Article
Evans, T. A., Fattahi, A., Deason, A. J., & Frenk, C. S. (2020). How Unusual is the Milky Way’s Assembly History?. Monthly Notices of the Royal Astronomical Society, 497(4), 4311-4321. https://doi.org/10.1093/mnras/staa2202

In the ΛCDM model of structure formation galactic haloes build up by accretion of mass and mergers of smaller haloes. The most recent massive merger event experienced by the Milky Way (MW) halo was the accretion of the Large Magellanic Cloud (LMC; wh... Read More about How Unusual is the Milky Way’s Assembly History?.

Quantifying the Stellar Halo's Response to the LMC's Infall with Spherical Harmonics (2020)
Journal Article
Cunningham, E. C., Garavito-Camargo, N., Deason, A. J., Johnston, K. V., Erkal, D., Laporte, C. F., …Sanderson, R. E. (2020). Quantifying the Stellar Halo's Response to the LMC's Infall with Spherical Harmonics. Astrophysical Journal, 898(1), Article 4. https://doi.org/10.3847/1538-4357/ab9b88

The vast majority of the mass in the Milky Way (MW) is in dark matter (DM); we therefore cannot directly observe the MW mass distribution and have to use tracer populations in order to infer properties of the MW DM halo. However, MW halo tracers do n... Read More about Quantifying the Stellar Halo's Response to the LMC's Infall with Spherical Harmonics.

The dual origin of the Galactic thick disc and halo from the gas-rich Gaia-Enceladus-Sausage merger (2020)
Journal Article
Pakmor, R., Marinacci, F., Gómez, F. A., Fragkoudi, F., Fattahi, A., Deason, A. J., …Grand, R. J. (2020). The dual origin of the Galactic thick disc and halo from the gas-rich Gaia-Enceladus-Sausage merger. Monthly Notices of the Royal Astronomical Society, 497(2), 1603-1618. https://doi.org/10.1093/mnras/staa2057

We analyse a set of cosmological magneto-hydrodynamic simulations of the formation of Milky Way-mass galaxies identified to have a prominent radially anisotropic stellar halo component similar to the so-called “Gaia Sausage” found in the Gaia data. W... Read More about The dual origin of the Galactic thick disc and halo from the gas-rich Gaia-Enceladus-Sausage merger.

The orbital phase space of contracted dark matter haloes (2020)
Journal Article
Pakmor, R., Marinacci, F., Grand, R. J., Frenk, C. S., Deason, A. J., Cautun, M., & Callingham, T. M. (2020). The orbital phase space of contracted dark matter haloes. Monthly Notices of the Royal Astronomical Society, 495(1), 12-28. https://doi.org/10.1093/mnras/staa1089

We study the orbital phase space of dark matter (DM) haloes in the AURIGA suite of cosmological hydrodynamics simulations of Milky Way (MW) analogues. We characterize haloes by their spherical action distribution, F(Jr,L)⁠, a function of the specific... Read More about The orbital phase space of contracted dark matter haloes.

The Edge of the Galaxy (2020)
Journal Article
Deason, A. J., Fattahi, A., Frenk, C. S., Grand, R. J., Oman, K. A., Garrison-Kimmel, S., …Navarro, J. F. (2020). The Edge of the Galaxy. Monthly Notices of the Royal Astronomical Society, 496(3), 3929-3942. https://doi.org/10.1093/mnras/staa1711

We use cosmological simulations of isolated Milky Way (MW)-mass galaxies, as well as Local Group (LG) analogues, to define the ‘edge’ – a caustic manifested in a drop in density or radial velocity – of Galactic-sized haloes, both in dark matter and i... Read More about The Edge of the Galaxy.

The little things matter: relating the abundance of ultrafaint satellites to the hosts’ assembly history (2020)
Journal Article
Frenk, C. S., Belokurov, V., Deason, A. J., & Bose, S. (2020). The little things matter: relating the abundance of ultrafaint satellites to the hosts’ assembly history. Monthly Notices of the Royal Astronomical Society, 495(1), 743-757. https://doi.org/10.1093/mnras/staa1199

Ultrafaint dwarf galaxies (M⋆ ≤ 105 M⊙) are relics of an early phase of galaxy formation. They contain some of the oldest and most metal-poor stars in the Universe which likely formed before the epoch of hydrogen reionisation. These galaxies are so f... Read More about The little things matter: relating the abundance of ultrafaint satellites to the hosts’ assembly history.

The Milky Way total mass profile as inferred from Gaia DR2 (2020)
Journal Article
Cautun, M., Benítez-Llambay, A., Deason, A. J., Frenk, C. S., Fattahi, A., Gómez, F. A., …Simpson, C. M. (2020). The Milky Way total mass profile as inferred from Gaia DR2. Monthly Notices of the Royal Astronomical Society, 494(3), 4291-4313. https://doi.org/10.1093/mnras/staa1017

We determine the Milky Way (MW) mass profile inferred from fitting physically motivated models to the Gaia DR2 Galactic rotation curve and other data. Using various hydrodynamical simulations of MW-mass haloes, we show that the presence of baryons in... Read More about The Milky Way total mass profile as inferred from Gaia DR2.

The biggest Splash (2020)
Journal Article
Grand, R. J., Evans, N. W., Deason, A. J., Smith, M. C., Fattahi, A., Sanders, J. L., & Belokurov, V. (2020). The biggest Splash. Monthly Notices of the Royal Astronomical Society, 494(3), 3880-3898. https://doi.org/10.1093/mnras/staa876

Using a large sample of bright nearby stars with accurate Gaia Data Release 2 astrometry and auxiliary spectroscopy we map out the properties of the principle Galactic components such as the “thin” and “thick” discs and the halo. We confirm previous... Read More about The biggest Splash.

The Nature of Ionized Gas in the Milky Way Galactic Fountain (2019)
Journal Article
Werk, J. K., Rubin, K., Bish, H., Prochaska, J., Zheng, Y., O’Meara, J., …Deason, A. (2019). The Nature of Ionized Gas in the Milky Way Galactic Fountain. Astrophysical Journal, 887(1), Article 89. https://doi.org/10.3847/1538-4357/ab54cf

We address the spatial scale, ionization structure, mass, and metal content of gas at the Milky Way disk–halo interface detected as absorption in the foreground of seven closely spaced, high-latitude halo blue horizontal branch stars with heights z =... Read More about The Nature of Ionized Gas in the Milky Way Galactic Fountain.

The total stellar halo mass of the Milky Way (2019)
Journal Article
Deason, A. J., Belokurov, V., & Sanders, J. L. (2019). The total stellar halo mass of the Milky Way. Monthly Notices of the Royal Astronomical Society, 490(3), 3426-3439. https://doi.org/10.1093/mnras/stz2793

We measure the total stellar halo luminosity using red giant branch (RGB) stars selected from Gaia data release 2. Using slices in magnitude, colour, and location on the sky, we decompose RGB stars belonging to the disc and halo by fitting two-dimens... Read More about The total stellar halo mass of the Milky Way.

Simulating cosmological substructure in the solar neighbourhood (2019)
Journal Article
Simpson, C. M., Gargiulo, I., Gómez, F. A., Grand, R. J., Maffione, N., Cooper, A. P., …Pakmor, R. (2019). Simulating cosmological substructure in the solar neighbourhood. Monthly Notices of the Royal Astronomical Society: Letters, 490(1), L32-L37. https://doi.org/10.1093/mnrasl/slz142

We explore the predictive power of cosmological, hydrodynamical simulations for stellar phase-space substructure and velocity correlations with the AURIGA simulations and AURIGAIA mock Gaia catalogues. We show that at the solar circle the AURIGA simu... Read More about Simulating cosmological substructure in the solar neighbourhood.

Galactic Gas Flows from Halo to Disk: Tomography and Kinematics at the Milky Way’s Disk–Halo Interface (2019)
Journal Article
Bish, H. V., Werk, J. K., Prochaska, J. X., Rubin, K. H., Zheng, Y., O’Meara, J. M., & Deason, A. J. (2019). Galactic Gas Flows from Halo to Disk: Tomography and Kinematics at the Milky Way’s Disk–Halo Interface. Astrophysical Journal, 882(2), Article 76. https://doi.org/10.3847/1538-4357/ab3414

We present a novel absorption-line survey using 54 blue horizontal branch stars in the Milky Way halo as background sources for detecting gas flows at the disk–halo interface. Distance measurements to high-latitude (b > 60°) background stars at 3.1–1... Read More about Galactic Gas Flows from Halo to Disk: Tomography and Kinematics at the Milky Way’s Disk–Halo Interface.

Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum (2019)
Journal Article
Kriss, G., De Rosa, G., Ely, J., Peterson, B., Kaastra, J., Mehdipour, M., …Zu, Y. (2019). Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum. Astrophysical Journal, 881(2), https://doi.org/10.3847/1538-4357/ab3049

We model the ultraviolet spectra of the Seyfert 1 galaxy NGC 5548 obtained with the Hubble Space Telescope during the 6 month reverberation mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblen... Read More about Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum.

HALO7D II: The Halo Velocity Ellipsoid and Velocity Anisotropy with Distant Main-sequence Stars (2019)
Journal Article
Cunningham, E. C., Deason, A. J., Sanderson, R. E., Sohn, S. T., Anderson, J., Guhathakurta, P., …Wetzel, A. (2019). HALO7D II: The Halo Velocity Ellipsoid and Velocity Anisotropy with Distant Main-sequence Stars. Astrophysical Journal, 879(2), Article 120. https://doi.org/10.3847/1538-4357/ab24cd

The Halo Assembly in Lambda Cold Dark Matter: Observations in 7 Dimensions (HALO7D) data set consists of Keck II/DEIMOS spectroscopy and Hubble Space Telescope–measured proper motions of Milky Way halo main-sequence turnoff stars in the CANDELS field... Read More about HALO7D II: The Halo Velocity Ellipsoid and Velocity Anisotropy with Distant Main-sequence Stars.

The Pisces Plume and the Magellanic wake (2019)
Journal Article
Belokurov, V., Deason, A. J., Erkal, D., Koposov, S. E., Carballo-Bello, J. A., Smith, M. C., …Navarrete, C. (2019). The Pisces Plume and the Magellanic wake. Monthly Notices of the Royal Astronomical Society: Letters, 488(1), L47-L52. https://doi.org/10.1093/mnrasl/slz101

Using RR Lyrae stars in the Gaia Data Release 2 and Pan-STARRS1 we study the properties of the Pisces overdensity, a diffuse substructure in the outer halo of the Milky Way. We show that along the line of sight, Pisces appears as a broad and long plu... Read More about The Pisces Plume and the Magellanic wake.

The effects of dynamical substructure on Milky Way mass estimates from the high-velocity tail of the local stellar halo (2019)
Journal Article
Grand, R. J., Deason, A. J., White, S. D., Simpson, C. M., Gómez, F. A., Marinacci, F., & Pakmor, R. (2019). The effects of dynamical substructure on Milky Way mass estimates from the high-velocity tail of the local stellar halo. Monthly Notices of the Royal Astronomical Society: Letters, 487(1), L72-L76. https://doi.org/10.1093/mnrasl/slz092

We investigate the impact of dynamical streams and substructure on estimates of the local escape speed and total mass of Milky-Way-mass galaxies from modelling the high-velocity tail of local halo stars. We use a suite of high-resolution magnetohydro... Read More about The effects of dynamical substructure on Milky Way mass estimates from the high-velocity tail of the local stellar halo.

HALO7D I. The Line-of-sight Velocities of Distant Main-sequence Stars in the Milky Way Halo (2019)
Journal Article
Cunningham, E. C., Deason, A. J., Rockosi, C. M., Guhathakurta, P., Jennings, Z. G., Kirby, E. N., …Barro, G. (2019). HALO7D I. The Line-of-sight Velocities of Distant Main-sequence Stars in the Milky Way Halo. Astrophysical Journal, 876(2), Article 124. https://doi.org/10.3847/1538-4357/ab16cb

The Halo Assembly in Lambda-CDM: Observations in 7 Dimensions (HALO7D) data set consists of Keck II/DEIMOS spectroscopy and Hubble Space Telescope–measured proper motions of Milky Way halo main-sequence turnoff stars in the CANDELS fields. In this pa... Read More about HALO7D I. The Line-of-sight Velocities of Distant Main-sequence Stars in the Milky Way Halo.

The Halo’s Ancient Metal-Rich Progenitor Revealed with BHB Stars (2019)
Journal Article
Lancaster, L., Koposov, S. E., Belokurov, V., Evans, N. W., & Deason, A. J. (2019). The Halo’s Ancient Metal-Rich Progenitor Revealed with BHB Stars. Monthly Notices of the Royal Astronomical Society, 486(1), 378-389. https://doi.org/10.1093/mnras/stz853

Using the data from the Sloan Digital Sky Survey and the Gaia satellite, we assemble a pure sample of ∼3000 Blue Horizontal Branch (BHB) stars with 7-D information, including positions, velocities and metallicities. We demonstrate that, as traced wit... Read More about The Halo’s Ancient Metal-Rich Progenitor Revealed with BHB Stars.

The local high-velocity tail and the Galactic escape speed (2019)
Journal Article
Deason, A. J., Fattahi, A., Belokurov, V., Evans, N. W., Grand, R. J., Marinacci, F., & Pakmor, R. (2019). The local high-velocity tail and the Galactic escape speed. Monthly Notices of the Royal Astronomical Society, 485(3), 3514-3526. https://doi.org/10.1093/mnras/stz623

We model the fastest moving (⁠v tot >300kms −1 vtot>300kms−1 ⁠) local (D ≲ 3 kpc) halo stars using cosmological simulations and six-dimensional Gaia data. Our approach is to use our knowledge of the assembly history and phase-space distribution of ha... Read More about The local high-velocity tail and the Galactic escape speed.

The mass of the Milky Way from satellite dynamics (2019)
Journal Article
Callingham, T. M., Cautun, M., Deason, A. J., Frenk, C. S., Wang, W., Gómez, F. A., …Pakmor, R. (2019). The mass of the Milky Way from satellite dynamics. Monthly Notices of the Royal Astronomical Society, 484(4), 5453-5467. https://doi.org/10.1093/mnras/stz365

We present and apply a method to infer the mass of the Milky Way (MW) by comparing the dynamics of MW satellites to those of model satellites in the EAGLE cosmological hydrodynamics simulations. A distribution function (DF) for galactic satellites is... Read More about The mass of the Milky Way from satellite dynamics.

The origin of galactic metal-rich stellar halo components with highly eccentric orbits (2019)
Journal Article
Fattahi, A., Belokurov, V., Deason, A. J., Frenk, C. S., Gómez, F. A., Grand, R. J., …Springel, V. (2019). The origin of galactic metal-rich stellar halo components with highly eccentric orbits. Monthly Notices of the Royal Astronomical Society, 484(4), 4471-4483. https://doi.org/10.1093/mnras/stz159

Using the astrometry from the ESA’s Gaia mission, previous works have shown that the Milky Way stellar halo is dominated by metal-rich stars on highly eccentric orbits. To shed light on the nature of this prominent halo component, we have analysed 28... Read More about The origin of galactic metal-rich stellar halo components with highly eccentric orbits.

The aftermath of the Great Collision between our Galaxy and the Large Magellanic Cloud (2018)
Journal Article
Cautun, M., Deason, A. J., Frenk, C. S., & McAlpine, S. (2018). The aftermath of the Great Collision between our Galaxy and the Large Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 483(2), 2185-2196. https://doi.org/10.1093/mnras/sty3084

The Milky Way (MW) offers a uniquely detailed view of galactic structure and is often regarded as a prototypical spiral galaxy. But recent observations indicate that the MW is atypical: it has an undersized supermassive black hole at its centre; it i... Read More about The aftermath of the Great Collision between our Galaxy and the Large Magellanic Cloud.

Aurigaia: mock Gaia DR2 stellar catalogues from the Auriga cosmological simulations (2018)
Journal Article
Grand, R., Helly, J., Fattahi, A., Cautun, M., Cole, S., Cooper, A., …Xu, D. (2018). Aurigaia: mock Gaia DR2 stellar catalogues from the Auriga cosmological simulations. Monthly Notices of the Royal Astronomical Society, 481(2), 1726-1743. https://doi.org/10.1093/mnras/sty2403

We present and analyse mock stellar catalogues that match the selection criteria and observables (including uncertainties) of the Gaia satellite data release 2 (DR2). The source are six cosmological high-resolution magneto-hydrodynamic ΛCDM zoom simu... Read More about Aurigaia: mock Gaia DR2 stellar catalogues from the Auriga cosmological simulations.

The Imprint of Cosmic Reionization on the Luminosity Function of Galaxies (2018)
Journal Article
Bose, S., Deason, A. J., & Frenk, C. S. (2018). The Imprint of Cosmic Reionization on the Luminosity Function of Galaxies. Astrophysical Journal, 863(2), Article 123. https://doi.org/10.3847/1538-4357/aacbc4

The (re)ionization of hydrogen in the early universe has a profound effect on the formation of the first galaxies: by raising the gas temperature and pressure, it prevents gas from cooling into small halos, thus affecting the abundance of present-day... Read More about The Imprint of Cosmic Reionization on the Luminosity Function of Galaxies.

Absolute Hubble Space Telescope Proper Motion (HSTPROMO) of Distant Milky Way Globular Clusters: Galactocentric Space Velocities and the Milky Way Mass (2018)
Journal Article
Sohn, S. T., Watkins, L. L., Fardal, M. A., van der Marel, R. P., Deason, A. J., Besla, G., & Bellini, A. (2018). Absolute Hubble Space Telescope Proper Motion (HSTPROMO) of Distant Milky Way Globular Clusters: Galactocentric Space Velocities and the Milky Way Mass. Astrophysical Journal, 862(1), Article 52. https://doi.org/10.3847/1538-4357/aacd0b

We present Hubble Space Telescope (HST) absolute proper motion (PM) measurements for 20 globular clusters (GCs) in the Milky Way (MW) halo at Galactocentric distances RGC » 10 100 – kpc, with a median per-coordinate PM uncertainty of 0.06 m - as yr 1... Read More about Absolute Hubble Space Telescope Proper Motion (HSTPROMO) of Distant Milky Way Globular Clusters: Galactocentric Space Velocities and the Milky Way Mass.

Apocenter Pile-up: Origin of the Stellar Halo Density Break (2018)
Journal Article
Deason, A. J., Belokurov, V., Koposov, S. E., & Lancaster, L. (2018). Apocenter Pile-up: Origin of the Stellar Halo Density Break. Astrophysical Journal Letters, 862(1), Article L1. https://doi.org/10.3847/2041-8213/aad0ee

We measure the orbital properties of halo stars using seven-dimensional information provided by Gaia and the Sloan Digital Sky Survey. A metal-rich population of stars, present in both local main sequence stars and more distant blue horizontal branch... Read More about Apocenter Pile-up: Origin of the Stellar Halo Density Break.

Evolution of LMC/M33-mass dwarf galaxies in the EAGLE simulation (2018)
Journal Article
Shao, S., Cautun, M., Deason, A., Frenk, C., & Theuns, T. (2018). Evolution of LMC/M33-mass dwarf galaxies in the EAGLE simulation. Monthly Notices of the Royal Astronomical Society, 479(1), 284-296. https://doi.org/10.1093/mnras/sty1470

We investigate the population of dwarf galaxies with stellar masses similar to the Large Magellanic Cloud (LMC) and M33 in the EAGLE galaxy formation simulation. In the field, galaxies reside in haloes with stellar-to-halo mass ratios of 1.03+0.50−0.... Read More about Evolution of LMC/M33-mass dwarf galaxies in the EAGLE simulation.

Co-formation of the disc and the stellar halo★ (2018)
Journal Article
Belokurov, V., Erkal, D., Evans, N., Koposov, S., & Deason, A. (2018). Co-formation of the disc and the stellar halo★. Monthly Notices of the Royal Astronomical Society, 478(1), 611-619. https://doi.org/10.1093/mnras/sty982

Using a large sample of main sequence stars with 7D measurements supplied by Gaia and SDSS, we study the kinematic properties of the local (within ∼10 kpc from the Sun) stellar halo. We demonstrate that the halo’s velocity ellipsoid evolves strongly... Read More about Co-formation of the disc and the stellar halo★.

Unmixing the Galactic Halo with RR Lyrae tagging (2018)
Journal Article
Belokurov, V., Deason, A., Koposov, S., Catelan, M., Erkal, D., Drake, A., & Evans, N. (2018). Unmixing the Galactic Halo with RR Lyrae tagging. Monthly Notices of the Royal Astronomical Society, 477(2), 1472-1483. https://doi.org/10.1093/mnras/sty615

We show that tagging RR Lyrae stars according to their location in the period-amplitude diagram can be used to shed light on the genesis of the Galactic stellar halo. The mixture of RR Lyrae of ab type, separated into classes along the lines suggeste... Read More about Unmixing the Galactic Halo with RR Lyrae tagging.

To the Galactic Virial Radius with Hyper Suprime-Cam (2018)
Journal Article
Deason, A. J., Belokurov, V., & Koposov, S. E. (2018). To the Galactic Virial Radius with Hyper Suprime-Cam. Astrophysical Journal, 852(2), Article 118. https://doi.org/10.3847/1538-4357/aa9d19

We exploit the exquisite, deep Hyper Suprime-Cam (HSC) imaging data to probe the Galactic halo out to 200 kpc. Using the ~100 square degree, multiband photometry of the first HSC Wide survey data release, we identify blue horizontal branch (BHB) star... Read More about To the Galactic Virial Radius with Hyper Suprime-Cam.

Cresting the wave: proper motions of the Eastern Banded Structure (2017)
Journal Article
Deason, A., Belokurov, V., & Koposo, V. S. (2018). Cresting the wave: proper motions of the Eastern Banded Structure. Monthly Notices of the Royal Astronomical Society, 473(2), 2428-2433. https://doi.org/10.1093/mnras/stx2528

We study the kinematic properties of the Eastern Banded Structure (EBS) and Hydra I overdensity using exquisite proper motions derived from the Sloan Digital Sky Survey (SDSS) and Gaia source catalogue. Main sequence turn-off stars in the vicinity of... Read More about Cresting the wave: proper motions of the Eastern Banded Structure.

Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy (2017)
Journal Article
Mathur, S., Gupta, A., Page, K., Pogge, R., Krongold, Y., Goad, M., …Zu, Y. (2017). Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy. Astrophysical Journal, 846(1), Article 55. https://doi.org/10.3847/1538-4357/aa832b

During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and... Read More about Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy.

The slight spin of the old stellar halo (2017)
Journal Article
Deason, A. J., Belokurov, V., Koposov, S. E., Gómez, F. A., Grand, R. J., Marinacci, F., & Pakmor, R. (2017). The slight spin of the old stellar halo. Monthly Notices of the Royal Astronomical Society, 470(2), 1259-1273. https://doi.org/10.1093/mnras/stx1301

We combine Gaia data release 1 astrometry with Sloan Digital Sky Survey (SDSS) images taken some ∼10–15 years earlier, to measure proper motions of stars in the halo of our Galaxy. The SDSS–Gaia proper motions have typical statistical errors of 2 mas... Read More about The slight spin of the old stellar halo.

Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548 (2017)
Journal Article
Pei, L., Fausnaugh, M., Barth, A., Peterson, B., Bentz, M., De Rosa, G., …Zu, Y. (2017). Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548. Astrophysical Journal, 837(2), Article 131. https://doi.org/10.3847/1538-4357/aa5eb1

We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multi-wavelength reverberation mapping campaign. The campaign spanned six months and achieved an almost daily cadence with observations from... Read More about Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548.

The Clouds are breaking: tracing the Magellanic system with Gaia DR1 Mira variables (2017)
Journal Article
Deason, A., Belokurov, V., Erkal, D., Koposov, S., & Mackey, D. (2017). The Clouds are breaking: tracing the Magellanic system with Gaia DR1 Mira variables. Monthly Notices of the Royal Astronomical Society, 467(3), 2636-2647. https://doi.org/10.1093/mnras/stx263

We exploit the first data release from the Gaia mission to identify candidate Mira variables in the outskirts of the Magellanic Clouds. The repeated observations of sources during the initial phase of the Gaia mission is used to identify stars that s... Read More about The Clouds are breaking: tracing the Magellanic system with Gaia DR1 Mira variables.

Clouds, Streams and Bridges. Redrawing the blueprint of the Magellanic System with Gaia DR1 (2016)
Journal Article
Belokurov, V., Erkal, D., Deason, A., Koposov, S., De Angeli, F., Wyn Evans, D., …Mackey, D. (2016). Clouds, Streams and Bridges. Redrawing the blueprint of the Magellanic System with Gaia DR1. Monthly Notices of the Royal Astronomical Society, 466(4), 4711-4730. https://doi.org/10.1093/mnras/stw3357

We present the discovery of stellar tidal tails around the Large and the Small Magellanic Clouds (LMC and SMC, respectively) in the Gaia DR1 data. In between the Clouds, their tidal arms are stretched towards each other to form an almost continuous s... Read More about Clouds, Streams and Bridges. Redrawing the blueprint of the Magellanic System with Gaia DR1.

The Eating Habits of Milky Way-mass Halos: Destroyed Dwarf Satellites and the Metallicity Distribution of Accreted Stars (2016)
Journal Article
Deason, A., Mao, Y., & Wechsler, R. (2016). The Eating Habits of Milky Way-mass Halos: Destroyed Dwarf Satellites and the Metallicity Distribution of Accreted Stars. Astrophysical Journal, 821(1), Article 5. https://doi.org/10.3847/0004-637x/821/1/5

We study the mass spectrum of destroyed dwarfs that contribute to the accreted stellar mass of Milky Way (MW) mass M_vir ~ 10^12.1 M_sun) halos using a suite of 45 zoom-in, dissipationless simulations. Empirical models are employed to relate (peak) s... Read More about The Eating Habits of Milky Way-mass Halos: Destroyed Dwarf Satellites and the Metallicity Distribution of Accreted Stars.

Isotropic at the Break? 3D Kinematics of Milky Way Halo Stars in the Foreground of M31 (2016)
Journal Article
Cunningham, E., Deason, A., Guhathakurta, P., Rockosi, C., van der Marel, R., Toloba, E., …Dorman, C. (2016). Isotropic at the Break? 3D Kinematics of Milky Way Halo Stars in the Foreground of M31. Astrophysical Journal, 820(1), Article 18. https://doi.org/10.3847/0004-637x/820/1/18

We present the line-of-sight (LOS) velocities for 13 distant main sequence Milky Way halo stars with published proper motions. The proper motions were measured using long baseline (5-7 years) multi-epoch HST/ACS photometry, and the LOS velocities wer... Read More about Isotropic at the Break? 3D Kinematics of Milky Way Halo Stars in the Foreground of M31.

Satellites of LMC-mass dwarfs: close friendships ruined by Milky Way mass haloes (2015)
Journal Article
Deason, A., Wetzel, A., Garrison-Kimmel, S., & Belokurov, V. (2015). Satellites of LMC-mass dwarfs: close friendships ruined by Milky Way mass haloes. Monthly Notices of the Royal Astronomical Society, 453(4), 3568-3574. https://doi.org/10.1093/mnras/stv1939

Motivated by the recent discovery of several dwarfs near the Large Magellanic Cloud (LMC), we study the accretion of massive satellites onto Milky Way (MW)/M31-like haloes using the ELVIS suite of N-body simulations. We identify 25 surviving LMC-mass... Read More about Satellites of LMC-mass dwarfs: close friendships ruined by Milky Way mass haloes.

Satellite Dwarf Galaxies in a Hierarchical Universe: Infall Histories, Group Preprocessing, and Reionization (2015)
Journal Article
Wetzel, A., Deason, A., & Garrison-Kimmel, S. (2015). Satellite Dwarf Galaxies in a Hierarchical Universe: Infall Histories, Group Preprocessing, and Reionization. Astrophysical Journal, 807(1), Article 49. https://doi.org/10.1088/0004-637x/807/1/49

In the Local Group (LG), almost all satellite dwarf galaxies that are within the virial radius of the Milky Way (MW) and Andromeda (M31) exhibit strong environmental influence. The orbital histories of these satellites provide the key to understandin... Read More about Satellite Dwarf Galaxies in a Hierarchical Universe: Infall Histories, Group Preprocessing, and Reionization.

The progenitors of the Milky Way stellar halo: big bricks favoured over little bricks (2015)
Journal Article
Deason, A., Belokurov, V., & Weisz, D. (2015). The progenitors of the Milky Way stellar halo: big bricks favoured over little bricks. Monthly Notices of the Royal Astronomical Society: Letters, 448(1), L77-L81. https://doi.org/10.1093/mnrasl/slv001

We present a census of blue horizontal branch (BHB) and blue straggler (BS) stars belonging to dwarf galaxies and globular clusters, and compare these counts to that of the Milky Way stellar halo. We find, in agreement with earlier studies, that the... Read More about The progenitors of the Milky Way stellar halo: big bricks favoured over little bricks.

TriAnd and its siblings: satellites of satellites in the Milky Way halo (2014)
Journal Article
Deason, A., Belokurov, V., Hamren, K., Koposov, S., Gilbert, K., Beaton, R., …Cunningham, E. (2014). TriAnd and its siblings: satellites of satellites in the Milky Way halo. Monthly Notices of the Royal Astronomical Society, 444(4), 3975-3985. https://doi.org/10.1093/mnras/stu1764

We explore the Triangulum–Andromeda (TriAnd) overdensity in the SPLASH (Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo) and SEGUE (the Sloan Extension for Galactic Understanding and Exploration) spectroscopic surveys. Milky Way m... Read More about TriAnd and its siblings: satellites of satellites in the Milky Way halo.

The cold veil of the Milky Way stellar halo (2012)
Journal Article
Deason, A., Belokurov, V., Evans, N., Koposov, S., Cooke, R., Peñarrubia, J., …Olszewski, E. (2012). The cold veil of the Milky Way stellar halo. Monthly Notices of the Royal Astronomical Society, 425(4), 2840-2853. https://doi.org/10.1111/j.1365-2966.2012.21639.x

We build a sample of distant (D > 80 kpc) stellar halo stars with measured radial velocities. Faint (20 < g < 22) candidate blue horizontal branch (BHB) stars were selected using the deep, but wide, multi-epoch Sloan Digital Sky Survey photometry. Fo... Read More about The cold veil of the Milky Way stellar halo.

Global structure and kinematics of stellar haloes in cosmological hydrodynamic simulations (2012)
Journal Article
McCarthy, I., Font, A., Crain, R., Deason, A., Schaye, J., & Theuns, T. (2012). Global structure and kinematics of stellar haloes in cosmological hydrodynamic simulations. Monthly Notices of the Royal Astronomical Society, 420(3), 2245-2262. https://doi.org/10.1111/j.1365-2966.2011.20189.x

We use the Galaxies–Intergalactic Medium Interaction Calculation (GIMIC) suite of cosmological hydrodynamical simulations to study the global structure and kinematics of stellar spheroids of Milky Way mass disc galaxies. Font et al. have recently dem... Read More about Global structure and kinematics of stellar haloes in cosmological hydrodynamic simulations.

Mismatch and misalignment: dark haloes and satellites of disc galaxies (2011)
Journal Article
Deason, A., McCarthy, I., Font, A., Evans, N., Frenk, C., Belokurov, V., …Theuns, T. (2011). Mismatch and misalignment: dark haloes and satellites of disc galaxies. Monthly Notices of the Royal Astronomical Society, 415(3), 2607-2625. https://doi.org/10.1111/j.1365-2966.2011.18884.x

We study the phase-space distribution of satellite galaxies associated with late-type galaxies in the GIMIC suite of simulations. GIMIC consists of resimulations of five cosmologically representative regions from the Millennium Simulation, which have... Read More about Mismatch and misalignment: dark haloes and satellites of disc galaxies.

Axi-symmetric models of auroral current systems in Jupiter's magnetosphere with predictions for the Juno mission (2008)
Journal Article
Cowley, S., Deason, A., & Bunce, E. (2008). Axi-symmetric models of auroral current systems in Jupiter's magnetosphere with predictions for the Juno mission. Annales Geophysicae, 26(12), 4051-4074. https://doi.org/10.5194/angeo-26-4051-2008

We develop two related models of magnetosphere-ionosphere coupling in the jovian system by combining previous models defined at ionospheric heights with magnetospheric magnetic models that allow system parameters to be extended appropriately into the... Read More about Axi-symmetric models of auroral current systems in Jupiter's magnetosphere with predictions for the Juno mission.