Joint Modeling of GD-1 and C-19 as Old Streams
Abstract
Abstract DESI observational data for the GD-1 and C-19 streams are compared to stream simulations in an evolving multihalo potential of a Milky Way–like galaxy based on a cosmological Milky Way–like simulation. The number of subhalos decreases with time, and the subhalo-stream encounter velocities rise as the galaxy and its disk build up their mass. The streams develop from star clusters inserted at ≃1 Gyr after the Big Bang and evolved for 13 Gyr to their current orbital positions. The measured velocity widths of the streams are compared to the matched simulations. Streams in a cold dark matter (CDM) subhalo population provide the best match to the velocity width, on average, with considerable scatter. Streams younger than ≃12 Gyr in CDM subhalos are insufficiently hot. Streams in the same potentials but with populations of warm dark matter (WDM) 5.5 keV subhalos are not, on average, heated to the observed velocity widths, although some of the realizations do reach the observed levels. The stream density power spectrum measured along the length of the DESI GD-1 sample agrees with the CDM stream simulations, with 1.3–2.3 times more power than WDM 7 and 5.5 keV simulations. The simulations show that modeling specific streams from the time of the formation of their progenitor clusters is both feasible and necessary to reproduce their stream-averaged kinematic properties.
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Authors: R G Carlberg, Ting S. Li, Emma Jarvis, Nasser Mohammed, Joan Najita, A Dey, Sergey E. Koposov, Jakob Piafsky, Leandro Beraldo e. Silva, Constance M. Rockosi, Aguilar Jl., Steven P. Ahlen, D Bianchi, D. Brooks, T. Claybaugh, A. de la Macorra, Biprateep Dey, P. Doel, Andreu Font-Ribera, J. E. Forero-Romero, Satya Gontcho A Gontcho, G. Gutierrez, R. Joyce, S. Junea, A. Kremin, O. Lahav, M. Landriau, Laurent Le Guillou, Aaron Meisner, R. Miquel, W. J. Percival, Claire Poppett, F. Prada, Ignasi Pérez-Ràfols, G. Rossi, E. Sanchez, D. Schlegel, J. Silber, G. Tarlé, B. A. Weaver, R. Zhou, H. Zou
Institutions: University of Pittsburgh, Universidad Nacional Autónoma de México, University of Virginia, University of Michigan, University of Toronto, Boston University, Consejo Superior de Investigaciones Científicas, University College London, Universidad Complutense de Madrid, University of Edinburgh, Sorbonne Université, Centre National de la Recherche Scientifique, University of Waterloo, Institució Catalana de Recerca i Estudis Avançats, Universitat Politècnica de Catalunya, University of Milan, Sejong University, National Astronomical Observatories, Lawrence Berkeley National Laboratory, Fermi National Accelerator Laboratory, NSF NOIRLab, Instituto de Astrofísica de Andalucía, National Institute for Astrophysics, Institut National de Physique Nucléaire et de Physique des Particules, Universidad de Los Andes, Brera Astronomical Observatory, Institute for High Energy Physics, Perimeter Institute, National Observatory