Professor Alis Deason's Outputs (94)

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., Cunningham, E. C., Deason, A. J., Guhathakurta, P., Guo, Y., Hernquist, L., Koo, D. C., McKinnon, K., Rockosi, C. M., Speagle, J. S., van Dokkum, P., & 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., Besla, G., Brown, T. M., Choi, Y., Deason, A., Fritz, T., Geha, M., Guhathakurta, P., Jeon, M., Kirby, E., Majewski, S. R., Patel, E., Simon, J. D., Tony Sohn, S., Tollerud, E., & 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?*.

The survival of globular clusters in a cuspy Fornax (2021)
Journal Article
Shao, S., Cautun, M., Frenk, C. S., Reina-Campos, M., Deason, A. J., Crain, R. A., Kruijssen, J. D., & Pfeffer, J. (2021). The survival of globular clusters in a cuspy Fornax. Monthly Notices of the Royal Astronomical Society, 507(2), 2339-2353. https://doi.org/10.1093/mnras/stab2285

It has long been argued that the globular clusters (GCs) in the Fornax dwarf galaxy indicate that its dark matter halo is likely to have a shallow density profile with a core of size ∼1 kpc. We revisit this argument by investigating analogues of Forn... Read More about The survival of globular clusters in a cuspy Fornax.

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., Zabludoff, A. I., & 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.-X., Koposov, S. E., Bird, S. A., Liu, C., Simion, I. T., Yang, C., Zhang, L., & 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., Kriss, G., Pei, L., Bentz, M., Cackett, E., Edelson, R., Eracleous, M., Goad, M., Grier, C., Kaastra, J., Kochanek, C., Krongold, Y., Mathur, S., Netzer, H., Proga, D., …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., Pakmor, R., Xue, X.-X., Liu, C., Yang, C., Zhang, L., & 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., Montes, M., Bahé, Y. M., Dalla Vecchia, C., Kay, S. T., & 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., Malkan, M., Rosa, G. D., Horne, K., Kriss, G., Arav, N., Bentz, M., Cackett, E., Bontà, E. D., Dehghanian, M., Done, C., Ferland, G., Grier, C., Kaastra, J., Kara, E., …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., Monachesi, A., Marinacci, F., & 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., Besla, G., Luger, R., & 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., Belokurov, V., Kawata, D., & 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., Simpson, C. M., & 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., Grand, R. J., Oman, K. A., Navarro, J. F., & 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.