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Helmi, Prof. Amina

Amina Helmi
Amina Helmi

Amina Helmi (1970) is Professor of Dynamics, Structure and Formation of the Milky Way. Helmi wrote a groundbreaking PhD thesis (for which she was awarded the 2004 Christiaan Huygens Prize), shedding new light on the history and formation of the Milky Way by stating that it probably gradually merged with smaller galaxies. Helmi is searching for these separate galaxies (‘fossils’) and is thus a sort of astro-archaeologist, using the information from star fossils to reconstruct the formation of the Milky Way.

Helmi has been awarded a number of prestigious grants, including an NWO VIDI grant in 2003 and an ERC Starting Grant from the EU in 2009. She is an active member of numerous networks. In 2017 she has been elected as member of the KNAW, the Royal Netherlands Academy of Arts and Sciences. Helmi is closely involved with the GAIA telescope, launched in 2013, which is providing very precise measurements to chart the Milky Way. II 2014 a team of scientists, including Helmi, published the first map of the spatial distribution of the mysterious matter in the almost empty space between stars, in Science. In 2015 she was awarded a VICI grant for her research, and in 2017 an NWO grant. In 2018 she and her research group were one of the first to be given the opportunity to study a second set of data from Gaia missions. She discovered that the Milky Way swallowed a major star system 10 billion years ago.

In 2019 Helmi was awarded the Spinoza Prize, the highest academic award in the Netherlands. Besides the great honour, the winner of the Spinoza Prize receives a research budget of EUR 2.5 million.

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Publications

2024

Grønnow, A., Fraternali, F., Marinacci, F., Pezzulli, G., Tolstoy, E., Helmi, A., & Brown, A. G. A. (2024). The density of the Milky Way’s corona at z ≈ 1.6 through ram pressure stripping of the Draco dSph galaxy. Monthly Notices of the Royal Astronomical Society, 528(2), 3009-3027. https://doi.org/10.1093/mnras/stae073

2023

Tolstoy, E., Skúladóttir, Á., Battaglia, G., Brown, A. G. A., Massari, D., Irwin, M. J., Starkenburg, E., Salvadori, S., Hill, V., Jablonka, P., Salaris, M., van Essen, T., Olsthoorn, C., Helmi, A., & Pritchard, J. (2023). A 3D view of dwarf galaxies with Gaia and VLT/FLAMES. I. The Sculptor dwarf spheroidal. Astronomy and Astrophysics, 675, Article A49. https://doi.org/10.1051/0004-6361/202245717
Woudenberg, H. C., Koop, O., Balbinot, E., & Helmi, A. (2023). Characterization and dynamics of the peculiar stream Jhelum: A tentative role for the Sagittarius dwarf galaxy. Astronomy and Astrophysics, 669, Article A102. https://doi.org/10.1051/0004-6361/202243266
Balbinot, E., Helmi, A., Callingham, T., Matsuno, T., Dodd, E., & Ruiz-Lara, T. (2023). ED-2: A cold but not so narrow stellar stream crossing the solar neighbourhood. Astronomy and Astrophysics, 678, Article A115. https://doi.org/10.1051/0004-6361/202347076
Babusiaux, C., Fabricius, C., Khanna, S., Muraveva, T., Reylé, C., Spoto, F., Vallenari, A., Luri, X., Arenou, F., Álvarez, M. A., Anders, F., Antoja, T., Balbinot, E., Barache, C., Bauchet, N., Bossini, D., Busonero, D., Cantat-Gaudin, T., Carrasco, J. M., ... Weiler, M. (2023). Gaia Data Release 3: Catalogue validation. Astronomy and Astrophysics, 674, Article A32. https://doi.org/10.1051/0004-6361/202243790
Gaia Collaboration, Creevey, O. L., Sarro, L. M., Lobel, A., Pancino, E., Andrae, R., Smart, R. L., Clementini, G., Heiter, U., Korn, A. J., Fouesneau, M., Frémat, Y., De Angeli, F., Vallenari, A., Harrison, D. L., Thévenin, F., Reylé, C., Sordo, R., Garofalo, A., ... Zhao, H. (2023). Gaia Data Release 3: A golden sample of astrophysical parameters. Astronomy and Astrophysics, 674, Article A39. https://doi.org/10.1051/0004-6361/202243800
Gaia Collaboration, Recio-Blanco, A., Kordopatis, G., de Laverny, P., Palicio, P. A., Spagna, A., Spina, L., Katz, D., Balbinot, E., Helmi, A., & Khanna, S. (2023). Gaia Data Release 3: Chemical cartography of the Milky Way. Astronomy & Astrophysics, 674, Article A38. https://doi.org/10.1051/0004-6361/202243511
Gaia Collaboration, Drimmel, R., Romero-Gomez, M., Chemin, L., Ramos, P., Poggio, C. E., Ripepi, V., Andrae, R., Khanna, S., Balbinot, E., & Helmi, A. (2023). Gaia Data Release 3: Mapping the asymmetric disc of the Milky Way. Astronomy & Astrophysics, 674, Article A37. https://doi.org/10.1051/0004-6361/202243797
Gaia Collaboration, De Ridder, J., Ripepi, V., Aerts, C., Palaversa, L., Eyer, L., Holl, B., Audard, M., Balbinot, E., Helmi, A., & Khanna, S. (2023). Gaia Data Release 3: Pulsations in main sequence OBAF-type stars. Astronomy & Astrophysics, 674, Article A36. https://doi.org/10.1051/0004-6361/202243767
Gaia Collaboration, Schultheis, M., Zhao, H., Zwitter, T., Marshall, D. J., Drimmel, R., Frémat, Y., Bailer-Jones, C. A. L., Balbinot, E., Helmi, A., & Khanna, S. (2023). Gaia Data Release 3: Exploring and mapping the diffuse interstellar band at 862 nm. Astronomy & Astrophysics, 674, Article A40. https://doi.org/10.1051/0004-6361/202243283
Gaia Collaboration, Vallenari, A., Brown, A. G. A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Biermann, M., Balbinot, E., Helmi, A., & Khanna, S. (2023). Gaia Data Release 3: Summary of the content and survey properties. Astronomy & Astrophysics, 674, Article A1. https://doi.org/10.1051/0004-6361/202243940
Gaia Collaboration, Arenou, F., Babusiaux, C., Barstow, M. A., Faigler, S., Jorissen, A., Kervella, P., Mazeh, T., Balbinot, E., Helmi, A., & Khanna, S. (2023). Gaia Data Release 3: Stellar multiplicity, a teaser for the hidden treasure. Astronomy & Astrophysics, 674, Article A34. https://doi.org/10.1051/0004-6361/202243782
Dodd, E., Callingham, T. M., Helmi, A., Matsuno, T., Ruiz-Lara, T., Balbinot, E., & Lövdal, S. (2023). Gaia DR3 view of dynamical substructure in the stellar halo near the Sun. Astronomy and Astrophysics, 670, Article L2. https://doi.org/10.1051/0004-6361/202244546
Gaia Collaboration, David, P., Mignard, F., Hestroffer, D., Tanga, P., Spoto, F., Berthier, J., Pauwels, T., Helmi, A., & Khanna, S. (2023). Gaia Focused Product Release: Asteroid orbital solution. Properties and assessment. Astronomy & Astrophysics, 680, Article A37. https://doi.org/10.1051/0004-6361/202347270
Gaia Collaboration, Weingrill, K., Mints, A., Castaneda, J., Kostrzewa-Rutkowska, Z., Davidson, M., De Angeli, F., Hernandez, J., Helmi, A., & Khanna, S. (2023). Gaia Focused Product Release: Sources from Service Interface Function image analysis. Half a million new sources in omega Centauri. Astronomy & Astrophysics, 680, Article A35. https://doi.org/10.1051/0004-6361/202347203
Gaia Collaboration, Trabucchi, M., Mowlavi, N., Lebzelter, T., Lecoeur-Taibi, I., Audard, M., Eyer, L., Garcia-Lario, P., Helmi, A., & Khanna, S. (2023). Gaia Focused Product Release: Radial velocity time series of long-period variables. Astronomy & Astrophysics, 680, Article A36. https://doi.org/10.1051/0004-6361/202347287
Gaia Collaboration, Schultheis, M., Zhao, H., Zwitter, T., Bailer-Jones, C. A. L., Carballo, R., Sordo, R., Drimmel, R., Helmi, A., & Khanna, S. (2023). Gaia Focused Product Release: Spatial distribution of two diffuse interstellar bands. Astronomy & Astrophysics, 680, Article A38. https://doi.org/10.1051/0004-6361/202347103
Viswanathan, A., Starkenburg, E., Koppelman, H. H., Helmi, A., Balbinot, E., & Esselink, A. F. (2023). Hidden deep in the halo: selection of a reduced proper motion halo catalogue and mining retrograde streams in the velocity space. Monthly Notices of the Royal Astronomical Society, 521(2), 2087-2102. https://doi.org/10.1093/mnras/stad380

2022

Borre, C. C., Aguirre Børsen-Koch, V., Helmi, A., Koppelman, H. H., Nielsen, M. B., Rørsted, J. L., Stello, D., Stokholm, A., Winther, M. L., Davies, G. R., Hon, M., Kruijssen, J. M. D., Laporte, C. F. P., Reyes, C., & Yu, J. (2022). Age determination of galaxy merger remnant stars using asteroseismology. Monthly Notices of the Royal Astronomical Society, 514(2), 2527-2544. https://doi.org/10.1093/mnras/stac1498
Reino, S., Rossi, E. M., Sanderson, R. E., Sellentin, E., Helmi, A., Koppelman, H. H., & Sharma, S. (2022). Erratum: Galactic potential constraints from clustering in action space of combined stellar stream data. Monthly Notices of the Royal Astronomical Society, 512, 4455-4463. https://doi.org/10.1093/mnras/stac694
Gaia Collaboration, Klioner, S. A., Lindegren, L., Mignard, F., Hernández, J., Ramos-Lerate, M., Bastian, U., Biermann, M., Bombrun, A., de Torres, A., Gerlach, E., Geyer, R., Hilger, T., Hobbs, D., Lammers, U. L., McMillan, P. J., Steidelmüller, H., Teyssier, D., Raiteri, C. M., ... Zhao, H. (2022). Gaia Early Data Release 3. The celestial reference frame (Gaia-CRF3). Astronomy and Astrophysics, 667, Article A148. https://doi.org/10.1051/0004-6361/202243483
Matsuno, T., Koppelman, H. H., Helmi, A., Aoki, W., Ishigaki, M. N., Suda, T., Yuan, Z., & Hattori, K. (2022). High-precision chemical abundances of Galactic building blocks: The distinct chemical abundance sequence of Sequoia. Astronomy and Astrophysics, 661, Article A103. https://doi.org/10.1051/0004-6361/202142752
Matsuno, T., Dodd, E., Koppelman, H. H., Helmi, A., Ishigaki, M. N., Aoki, W., Zhao, J., Yuan, Z., & Hattori, K. (2022). High-precision chemical abundances of Galactic building blocks: II. Revisiting the chemical distinctness of the Helmi streams. Astronomy and Astrophysics, 665, Article A46. https://doi.org/10.1051/0004-6361/202243609
Lövdal, S. S., Ruiz-Lara, T., Koppelman, H. H., Matsuno, T., Dodd, E., & Helmi, A. (2022). Substructure in the stellar halo near the Sun: I. Data-driven clustering in integrals-of-motion space. Astronomy and Astrophysics, 665, Article A57. https://doi.org/10.1051/0004-6361/202243060
Ruiz-Lara, T., Matsuno, T., Lövdal, S. S., Helmi, A., Dodd, E., & Koppelman, H. H. (2022). Substructure in the stellar halo near the Sun. II. Characterisation of independent structures. Astronomy and Astrophysics, 665, Article A58. https://doi.org/10.1051/0004-6361/202243061
Dodd, E., Helmi, A., & Koppelman, H. H. (2022). Substructures, resonances, and debris streams: A new constraint on the inner shape of the Galactic dark halo. Astronomy and Astrophysics, 659, Article A61. https://doi.org/10.1051/0004-6361/202141354
Ruiz-Lara, T., Helmi, A., Gallart, C., Surot, F., & Cassisi, S. (2022). Unveiling the past evolution of the progenitor of the Helmi streams. Astronomy and Astrophysics, 668, L10. https://doi.org/10.1051/0004-6361/202244127

2021

Gaia Collaboration (2021). Corrigendum: Gaia Early Data Release 3. Summary of the contents and survey properties. Astronomy and Astrophysics, 650, C3. https://doi.org/10.1051/0004-6361/202039657e
Koppelman, H. H., & Helmi, A. (2021). Determination of the escape velocity of the Milky Way using a halo sample selected based on proper motion. Astronomy and Astrophysics, 649, Article A136. https://doi.org/10.1051/0004-6361/202038777
Koppelman, H. H., Hagen, J. H. J., & Helmi, A. (2021). Frequencies, chaos, and resonances: A study of orbital parameters of nearby thick-disc and halo stars. Astronomy & Astrophysics, 647(March 2021), Article A37. https://doi.org/10.1051/0004-6361/202039390
Gaia Collaboration, Klioner, S. A., Mignard, F., Lindegren, L., Bastian, U., McMillan, P. J., Hernández, J., Hobbs, D., Ramos-Lerate, M., Biermann, M., Bombrun, A., de Torres, A., Gerlach, E., Geyer, R., Hilger, T., Lammers, U., Steidelmüller, H., Stephenson, C. A., Brown, A. G. A., ... Siebert, A. (2021). Gaia Early Data Release 3. Acceleration of the Solar System from Gaia astrometry. Astronomy and Astrophysics, 649, Article A9. https://doi.org/10.1051/0004-6361/202039734
Fabricius, C., Luri, X., Arenou, F., Babusiaux, C., Helmi, A., Muraveva, T., Reylé, C., Spoto, F., Vallenari, A., Antoja, T., Balbinot, E., Barache, C., Bauchet, N., Bragaglia, A., Busonero, D., Cantat-Gaudin, T., Carrasco, J. M., Diakité, S., Fabrizio, M., ... Weiler, M. (2021). Gaia Early Data Release 3. Catalogue validation. Astronomy and Astrophysics, 649, Article A5. https://doi.org/10.1051/0004-6361/202039834
Gaia Collaboration, Luri, X., Chemin, L., Clementini, G., Delgado, H. E., McMillan, P. J., Romero-Gómez, M., Balbinot, E., Helmi, A., Teyssier, D., Robin, A. C., Smith, M., Khanna, S., & Massari, D. (2021). Gaia Early Data Release 3. Structure and properties of the Magellanic Clouds. Astronomy and Astrophysics, 649, Article A7. https://doi.org/10.1051/0004-6361/202039588
Gaia Collaboration, Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Babusiaux, C., Biermann, M., Creevey, O. L., Evans, D. W., Eyer, L., Hutton, A., Jansen, F., Jordi, C., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., Mignard, F., Panem, C., ... Siebert, A. (2021). Gaia Early Data Release 3. Summary of the contents and survey properties. Astronomy and Astrophysics, 649, Article A1. https://doi.org/10.1051/0004-6361/202039657
Gaia Collaboration, Smart, R. L., Sarro, L. M., Rybizki, J., Reylé, C., Robin, A. C., Hambly, N. C., Abbas, U., Balbinot, E., Helmi, A., & Khanna, S. (2021). Gaia Early Data Release 3. The Gaia Catalogue of Nearby Stars. Astronomy and Astrophysics, 649, A6. https://doi.org/10.1051/0004-6361/202039498
Gaia Collaboration, Antoja, T., McMillan, P. J., Kordopatis, G., Ramos, P., Helmi, A., Balbinot, E., Cantat-Gaudin, T., Chemin, L., Figueras, F., Jordi, C., Khanna, S., Romero-Gómez, M., Seabroke, G. M., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Babusiaux, C., ... Siebert, A. (2021). Gaia Early Data Release 3. The Galactic anticentre. Astronomy and Astrophysics, 649, Article A8. https://doi.org/10.1051/0004-6361/202039714
Luri, X., Fabricius, C., Antoja, T., Arenou, F., Babusiaux, C., Balbinot, E., Barache, C., Bauchet, N., Carrasco, J. M., Diakité, S., Figueras, F., Garcia-Gutierrez, A., Helmi, A., Jordi, C., Khanna, S., Leclerc, N., Masip, A., Muraveva, T., Ramos, P., ... Weiler, M. (2021). Gaia EDR3 documentation Chapter 8: Gaia EDR3 documentation Chapter 8: Validation. EUROPEAN SPACE AGENCY. https://ui.adsabs.harvard.edu/abs/2021gdr3.reptE...8L
Reino, S., Rossi, E. M., Sanderson, R. E., Sellentin, E., Helmi, A., Koppelman, H. H., & Sharma, S. (2021). Galactic potential constraints from clustering in action space of combined stellar stream data. Monthly Notices of the Royal Astronomical Society, 502(3), 4170-4193. https://doi.org/10.1093/mnras/stab304
Recio-Blanco, A., Fernández-Alvar, E., de Laverny, P., Antoja, T., Helmi, A., & Crida, A. (2021). Heavy-elements heritage of the falling sky. Astronomy and Astrophysics, 648, Article A108. https://doi.org/10.1051/0004-6361/202038943
Balbinot, E., & Helmi, A. (2021). Linking nearby stellar streams to more distant halo overdensities. Astronomy and Astrophysics, 654, Article A15. https://doi.org/10.1051/0004-6361/202141015
Valentijn, E. A., Lineweaver, C. H., van der Velde, K. J., Scholtens, S., Amunts, K., Schemmel, J., Silvestri, A., Helmi, A., Ynnerman, A., Brouwer, M., Falcke, H., Vandersypen, L., van Haarlem, M., Samardjiska, S., & Sloot, P. (2021). People’s information Universe. In E. A. Valentijn (Ed.), Powers of Two: The Information Universe - Information as the Building Block of Everything (pp. 23-106). Springer. https://doi.org/10.1007/978-3-030-58345-3_3
Matsuno, T., Hirai, Y., Tarumi, Y., Hotokezaka, K., Tanaka, M., & Helmi, A. (2021). R-process enhancements of Gaia-Enceladus in GALAH DR3. Astronomy and Astrophysics, 650, Article A110. https://doi.org/10.1051/0004-6361/202040227
Koppelman, H. H., & Helmi, A. (2021). The reduced proper motion selected halo: Methods and description of the catalogue. Astronomy & Astrophysics, 645(January 2021), Article A69. https://doi.org/10.1051/0004-6361/202038178
Koppelman, H. H., & Helmi, A. (2021). Time evolution of gaps in stellar streams in axisymmetric Stäckel potentials. Astronomy and Astrophysics, 649, Article A55. https://doi.org/10.1051/0004-6361/202039968
Skúladóttir, Á., Salvadori, S., Amarsi, A. M., Tolstoy, E., Irwin, M. J., Hill, V., Jablonka, P., Battaglia, G., Starkenburg, E., Massari, D., Helmi, A., & Posti, L. (2021). Zero-metallicity Hypernova Uncovered by an Ultra-metal-poor Star in the Sculptor Dwarf Spheroidal Galaxy. The Astrophysical Journal, 915(2), Article L30. https://doi.org/10.3847/2041-8213/ac0dc2

2020

Antoja, T., Ramos, P., Mateu, C., Helmi, A., Anders, F., Jordi, C., & Carballo-Bello, J. A. (2020). An all-sky proper-motion map of the Sagittarius stream using Gaia DR2. Astronomy & Astrophysics, 635, Article 3. https://doi.org/10.1051/0004-6361/201937145
Matsuno, T., Koppelman, H. H., & Helmi, A. (2020). Bright Stars from the Ancient Merger Gaia-Enceladus Visible with Binoculars. Research Notes of the AAS, 4(12), Article 246. https://doi.org/10.3847/2515-5172/abd4d1
Gaia Collaboration (2020). Corrigendum: Gaia Data Release 2 Kinematics of globular clusters and dwarf galaxies around the Milky Way. Astronomy & Astrophysics, 637, Article C3. https://doi.org/10.1051/0004-6361/201832698e
Elias, L. M., Sales, L. V., Helmi, A., & Hernquist, L. (2020). Cosmological insights into the assembly of the radial and compact stellar halo of the Milky Way. Monthly Notices of the Royal Astronomical Society, 495(1), 29-39. https://doi.org/10.1093/mnras/staa1090
Ramos, P., Mateu, C., Antoja, T., Helmi, A., Castro-Ginard, A., Balbinot, E., & Carrasco, J. M. (2020). Full 5D characterisation of the Sagittarius stream with Gaia DR2 RR Lyrae. Astronomy & Astrophysics, 638, Article A104. https://doi.org/10.1051/0004-6361/202037819
Ramos, P., Mateu, C., Antoja, T., Helmi, A., Castro-Ginard, A., Balbinot, E., & Carrasco, J. M. (2020). Full 5D characterisation of the Sagittarius stream with Gaia DR2 RR Lyrae (Corrigendum). Astronomy & Astrophysics, 640, Article C5. https://doi.org/10.1051/0004-6361/202037819e
Gaia Collaboration, Helmi, A., Massari, D., Breddels, M. A., & Veljanoski, J. (2020). Gaia Data Release 2. The kinematics of globular clusters and dwarf galaxies around the Milky Way (Corrigendum). Astronomy & Astrophysics, 642, Article C1. https://doi.org/10.1051/0004-6361/202039217
Massari, D., Helmi, A., Mucciarelli, A., Sales, L., Spina, L., & Tolstoy, E. (2020). Stellar 3D kinematics in the Draco dwarf spheroidal galaxy. Astronomy & Astrophysics, 633, Article 36. https://doi.org/10.1051/0004-6361/201935613
Helmi, A. (2020). Streams, Substructures, and the Early History of the Milky Way. Annual Review of Astronomy and Astrophysics, 58, 205-256. https://doi.org/10.1146/annurev-astro-032620-021917
Theler, R., Jablonka, P., Lucchesi, R., Lardo, C., North, P., Irwin, M., Battaglia, G., Hill, V., Tolstoy, E., Venn, K., Helmi, A., Kaufer, A., Primas, F., & Shetrone, M. (2020). The chemical evolution of the dwarf spheroidal galaxy Sextans. Astronomy & Astrophysics, 642, Article A176. https://doi.org/10.1051/0004-6361/201937146
Ramos, P., Antoja, T., Mateu, C., Helmi, A., Castro-Ginard, A., Anders, F., Jordi, C., Carballo-Bello, J. A., Balbinot, E., & Carrasco, J. M. (2020). The Halo-Disc dynamical coupling: Gaia blind detection of the Monoceros and ACS structures. Paper presented at XIV.0 Scientific Meeting (virtual) of the Spanish Astronomical Society, held 13-15 July 2020.
Koppelman, H. H., Bos, R. O. Y., & Helmi, A. (2020). The messy merger of a large satellite and a Milky Way-like galaxy. Astronomy & Astrophysics, 642, Article L18. https://doi.org/10.1051/0004-6361/202038652
Antoja, T., Ramos, P., Mateu, C., Helmi, A., Castro-Ginard, A., Anders, F., Jordi, C., Carballo-Bello, J. A., Balbinot, E., & Carrasco, J. M. (2020). The Sagittarius stream with Gaia data. Paper presented at EA XIV.0 Reunión Científica .
RAVE Collaboration (2020). The Sixth Data Release of the Radial Velocity Experiment (Rave). II. Stellar Atmospheric Parameters, Chemical Abundances, and Distances. The Astronomical Journal, 160(2), Article 83. https://doi.org/10.3847/1538-3881/ab9ab8
RAVE Collaboration (2020). The Sixth Data Release of the Radial Velocity Experiment (RAVE). I. Survey Description, Spectra, and Radial Velocities. The Astronomical Journal, 160(2), Article 82. https://doi.org/10.3847/1538-3881/ab9ab9

2019

4MOST, de Jong, R. S., Agertz, O., Agudo Berbel, A., Aird, J., Alexander, D. A., Amarsi, A., Anders, F., Andrae, R., Ansarinejad, B., Ansorge, W., Antilogus, P., Anwand-Heerwart, H., Arentsen, A., Arnadottir, A., Asplund, M., Auger, M., Azais, N., Baade, D., ... Kuijken, K. (2019). 4MOST: Project overview and information for the First Call for Proposals. ESO Messenger, 175. http://adsabs.harvard.edu/abs/2019arXiv190302464D
Helmi, A., Irwin, M., Deason, A., Balbinot, E., Belokurov, V., Bland-Hawthorn, J., Christlieb, N., Cioni, M. .-R. L., Feltzing, S., Grebel, E. K., Kordopatis, G., Starkenburg, E., Walton, N., & Worley, C. C. (2019). 4MOST Consortium Survey 1: The Milky Way Halo Low-Resolution Survey. The Messenger, 175, 23-25. https://doi.org/10.18727/0722-6691/5120
Christlieb, N., Battistini, C., Bonifacio, P., Caffau, E., Ludwig, H. .-G., Asplund, M., Barklem, P., Bergemann, M., Church, R., Feltzing, S., Ford, D., Grebel, E. K., Hansen, C. J., Helmi, A., Kordopatis, G., Kovalev, M., Korn, A., Lind, K., Quirrenbach, A., ... Starkenburg, E. (2019). 4MOST Consortium Survey 2: The Milky Way Halo High-Resolution Survey. The Messenger, 175, 26-29. https://doi.org/10.18727/0722-6691/5121
Bignone, L. A., Helmi, A., & Tissera, P. B. (2019). A Gaia-Enceladus Analog in the EAGLE Simulation: Insights into the Early Evolution of the Milky Way. Astrophysical Journal Letters, 883(1), Article 5. https://doi.org/10.3847/2041-8213/ab3e0e
Hagen, J. H. J., Helmi, A., & Breddels, M. A. (2019). Axisymmetric Schwarzschild models of an isothermal axisymmetric mock dwarf spheroidal galaxy. Astronomy & Astrophysics, 632, Article 99. https://doi.org/10.1051/0004-6361/201936196
Koppelman, H. H., Helmi, A., Massari, D., Roelenga, S., & Bastian, U. (2019). Characterization and history of the Helmi streams with Gaia DR2. Astronomy and Astrophysics, 625, Article A5. https://doi.org/10.1051/0004-6361/201834769
Gaia Collaboration (2019). Gaia Data Release 2. Variable stars in the colour-absolute magnitude diagram. Astronomy and Astrophysics, 623, Article A110. https://doi.org/10.1051/0004-6361/201833304
Posti, L., & Helmi, A. (2019). Mass and shape of the Milky Way's dark matter halo with globular clusters from Gaia and Hubble. Astronomy & Astrophysics, 621, Article 56. https://doi.org/10.1051/0004-6361/201833355
Koppelman, H. H., Helmi, A., Massari, D., Price-Whelan, A. M., & Starkenburg, T. K. (2019). Multiple retrograde substructures in the Galactic halo: A shattered view of Galactic history. Astronomy & Astrophysics, 631, Article L9. https://doi.org/10.1051/0004-6361/201936738
Massari, D., Koppelman, H. H., & Helmi, A. (2019). Origin of the system of globular clusters in the Milky Way. Astronomy & Astrophysics, 630, Article L4. https://doi.org/10.1051/0004-6361/201936135
Sakari, C. M., Roederer, I. U., Placco, V. M., Beers, T. C., Ezzeddine, R., Frebel, A., Hansen, T., Sneden, C., Cowan, J. J., Wallerstein, G., Farrell, E. M., Venn, K. A., Matijevi─Ź, G., Wyse, R. F. G., Bland-Hawthorn, J., Chiappini, C., Freeman, K. C., Gibson, B. K., Grebel, E. K., ... Watson, F. (2019). The R-Process Alliance: Discovery of a Low-╬▒, r-process-enhanced Metal-poor Star in the Galactic Halo. The Astrophysical Journal, 874(2), Article 148. https://doi.org/10.3847/1538-4357/ab0c02
Hagen, J. H. J., Helmi, A., de Zeeuw, P. T., & Posti, L. (2019). The tilt of the velocity ellipsoid in the Milky Way with Gaia DR2. Astronomy & Astrophysics, 629, 1-14. Article A70. https://doi.org/10.1051/0004-6361/201935264
Hill, V., Skúladóttir, Á., Tolstoy, E., Venn, K. A., Shetrone, M. D., Jablonka, P., Primas, F., Battaglia, G., de Boer, T. J. L., François, P., Helmi, A., Kaufer, A., Letarte, B., Starkenburg, E., & Spite, M. (2019). VLT/FLAMES high-resolution chemical abundances in Sculptor: a textbook dwarf spheroidal galaxy. Astronomy and Astrophysics, 626, Article A15. https://doi.org/10.1051/0004-6361/201833950

2018

Antoja, T., Helmi, A., Romero-Gómez, M., Katz, D., Babusiaux, C., Drimmel, R., Evans, D. W., Figueras, F., Poggio, E., Reylé, C., Robin, A. C., Seabroke, G., & Soubiran, C. (2018). A dynamically young and perturbed Milky Way disk. Nature, 561(7723), 360-362. https://doi.org/10.1038/s41586-018-0510-7
Letarte, B., Hill, V., Tolstoy, E., Jablonka, P., Shetrone, M., Venn, K. A., Spite, M., Irwin, M. J., Battaglia, G., Helmi, A., Primas, F., François, P., Kaufer, A., Szeifert, T., Arimoto, N., & Sadakane, K. (2018). Corrigendum: A high-resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy. Astronomy and Astrophysics, 613, C1. https://doi.org/10.1051/0004-6361/200913413e
Gaia Collaboration (2018). Gaia Data Release 2: Kinematics of globular clusters and dwarf galaxies around the Milky Way. Astronomy & Astrophysics, 616, A12. Article 12. https://doi.org/10.1051/0004-6361/201832698
Gaia Collaboration (2018). Gaia Data Release 2: Observational Hertzsprung-Russell diagrams. Unpublished. https://doi.org/10.1051/0004-6361/201832843
Arenou, F., Luri, X., Babusiaux, C., Fabricius, C., Helmi, A., Muraveva, T., Robin, A. C., Spoto, F., Vallenari, A., Antoja, T., Cantat-Gaudin, T., Jordi, C., Leclerc, N., Reyle, C., Romero-Gomez, M., Shih, I. .-C., Soria, S., Barache, C., Bossini, D., ... Zurbach, C. (2018). Gaia Data Release 2: Catalogue validation. Unpublished. https://doi.org/10.1051/0004-6361/201833234
Gaia Collaboration (2018). Gaia Data Release 2: The celestial reference frame (Gaia-CRF2). Astronomy and Astrophysics, 616, Article A14. https://doi.org/10.1051/0004-6361/201832916
Gaia Collaboration (2018). Gaia Data Release 2: Observations of solar system objects. Astronomy & Astrophysics, 616, Article 13. https://doi.org/10.1051/0004-6361/201832900
Gaia Collaboration (2018). Gaia Data Release 2: Mapping the Milky Way disc kinematics. Astronomy & Astrophysics, 616, Article 11. https://doi.org/10.1051/0004-6361/201832865
Gaia Collaboration (2018). Gaia Data Release 2: Summary of the contents and survey properties. Astronomy & Astrophysics, 616, Article 1. https://doi.org/10.1051/0004-6361/201833051
McMillan, P. J., Kordopatis, G., Kunder, A., Binney, J., Wojno, J., Zwitter, T., Steinmetz, M., Bland-Hawthorn, J., Gibson, B. K., Gilmore, G., Grebel, E. K., Helmi, A., Munari, U., Navarro, J. F., Parker, Q. A., Seabroke, G., Watson, F., & Wyse, R. F. G. (2018). Improved distances and ages for stars common to TGAS and RAVE. Monthly Notices of the Royal Astronomical Society, 477(4), 5279-5300. https://doi.org/10.1093/mnras/sty990
Carrillo, I., Minchev, I., Kordopatis, G., Steinmetz, M., Binney, J., Anders, F., Bienaymé, O., Bland-Hawthorn, J., Famaey, B., Freeman, K. C., Gilmore, G., Gibson, B. K., Grebel, E. K., Helmi, A., Just, A., Kunder, A., McMillan, P., Monari, G., Munari, U., ... Zwitter, T. (2018). Is the Milky Way still breathing? RAVE-Gaia streaming motions. Monthly Notices of the Royal Astronomical Society, 475(2), 2679-2696. https://doi.org/10.1093/mnras/stx3342
Koppelman, H., Helmi, A., & Veljanoski, J. (2018). One Large Blob and Many Streams Frosting the nearby Stellar Halo in Gaia~DR2. Astrophysical Journal Letters, 860(1), Article L11. https://doi.org/10.3847/2041-8213/aac882
Posti, L., Helmi, A., Veljanoski, J., & Breddels, M. A. (2018). The dynamically selected stellar halo of the Galaxy with Gaia and the tilt of the velocity ellipsoid. Astronomy and Astrophysics, 615, Article A70. https://doi.org/10.1051/0004-6361/201732277
Hagen, J. H. J., & Helmi, A. (2018). The kinematics and surface mass density in the solar neighbourhood using TGASxRAVE. In A. Recio-Blanco, P. de Laverny, A. G. A. Brown, & T. Prusti (Eds.), Proceedings of the International Astronomical Unian: Astrometry and astrophysics in the Gaia sky (Vol. 12, pp. 160-163). Cambridge University Press. https://doi.org/10.1017/S1743921317005725
Helmi, A., Babusiaux, C., Koppelman, H. H., Massari, D., Veljanoski, J., & Brown, A. G. A. (2018). The merger that led to the formation of the Milky Way’s inner stellar halo and thick disk. Nature, 563(7729), 85-88. https://doi.org/10.1038/s41586-018-0625-x
Sakari, C. M., Placco, V. M., Farrell, E. M., Roederer, I. U., Wallerstein, G., Beers, T. C., Ezzeddine, R., Frebel, A., Hansen, T., Holmbeck, E. M., Sneden, C., Cowan, J. J., Venn, K. A., Davis, C. E., Matijevic, G., Wyse, R. F. G., Bland-Hawthorn, J., Chiappini, C., Freeman, K. C., ... Watson, F. (2018). The R-Process Alliance: First Release from the Northern Search for r-process-enhanced Metal-poor Stars in the Galactic Halo. The Astrophysical Journal, 868(2), Article 110. https://doi.org/10.3847/1538-4357/aae9df
Hagen, J. H. J., & Helmi, A. (2018). The surface mass density in the solar neighbourhood using red clumps stars in TGASxRAVE. In C. Chiappini, I. Minchev, E. Starkenburg, & M. Valentini (Eds.), Rediscovering Our Galaxy (pp. 304-305). (Proceedings of the International Astronomical Union Symposia and Colloquia; Vol. S334). Cambridge University Press. https://doi.org/10.1017/S1743921317006524
Koppelman, H. H., & Helmi, A. (2018). The time evolution of gaps in tidal streams in axisymmetric potentials. In A. Recio-Blanco, P. de Laverny, A. G. A. Brown, & T. Prusti (Eds.), Proceedings of the International Astronomical Union: Astrometry and Astrophysics in the Gaia sky (Vol. 12, pp. 229-230). Cambridge University Press. https://doi.org/10.1017/S1743921317006135
Hagen, J. H. J., & Helmi, A. (2018). The vertical force in the solar neighbourhood using red clump stars in TGAS and RAVE: Constraints on the local dark matter density. Astronomy and Astrophysics, 615, Article A99. https://doi.org/10.1051/0004-6361/201832903
Massari, D., Breddels, M. A., Helmi, A., Posti, L., Brown, A. G. A., & Tolstoy, E. (2018). Three-dimensional motions in the Sculptor dwarf galaxy as a glimpse of a new era. Nature Astronomy, 2(2), 156-161. Article A70. https://doi.org/10.1038/s41550-017-0322-y
Koppelman, H. H., & Helmi, A. (2018). Time evolution of the properties of gaps in stellar streams in axisymmetric potentials. In C. Chiappini, I. Minchev, E. Starkenburg, & M. Valentini (Eds.), Rediscovering Our Galaxy (pp. 321-322). (Proceedings of the International Astronomical Union Symposia and Colloquia; Vol. S334). Cambridge University Press. https://doi.org/10.1017/S1743921317006901
Veljanoski, J., Posti, L., Helmi, A., & Breddels, M. A. (2018). Unveiling the stellar halo with TGAS. In A. Recio-Blanco, P. de Laverny, A. G. A. Brown, & T. Prusti (Eds.), Proceedings of the International Astronomical Union: Astrometry and Astrophysics in the Gaia sky (Vol. 12, pp. 275-276). Cambridge University Press. https://doi.org/10.1017/S1743921317007141
Massari, D., & Helmi, A. (2018). With and without spectroscopy: Gaia DR2 proper motions of seven Ultra- Faint Dwarf Galaxies. Astronomy & Astrophysics, 620, Article A155. https://doi.org/10.1051/0004-6361/201833367

2017

Helmi, A., Veljanoski, J., Breddels, M. A., Tian, H., & Sales, L. V. (2017). A box full of chocolates: The rich structure of the nearby stellar halo revealed by Gaia and RAVE. Astronomy and Astrophysics, 598, Article A58. https://doi.org/10.1051/0004-6361/201629990
Antoja, T., Kordopatis, G., Helmi, A., Monari, G., Famaey, B., Wyse, R. F. G., Grebel, E. K., Steinmetz, M., Bland-Hawthorn, J., Gibson, B. K., Bienaymé, O., Navarro, J. F., Parker, Q. A., Reid, W., Seabroke, G., Siebert, A., Siviero, A., & Zwitter, T. (2017). Asymmetric metallicity patterns in the stellar velocity space with RAVE. Astronomy & Astrophysics, 601, Article A59. https://doi.org/10.1051/0004-6361/201629387
Buist, H. J. T., & Helmi, A. (2017). Behaviour of streams in angle and frequency spaces in different potentials. Astronomy & Astrophysics, 601, Article 37. https://doi.org/10.1051/0004-6361/201527930
van Oirschot, P., Starkenburg, E., Helmi, A., & Nelemans, G. (2017). Building blocks of the Milky Way's accreted spheroid. Monthly Notices of the Royal Astronomical Society, 464(1), 863-875. https://doi.org/10.1093/mnras/stw2340
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