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SatGen: a semi-analytical satellite galaxy generator -- I. The model and its application to Local-Group satellite statistics

Jiang, Fangzhou and Dekel, Avishai and Freundlich, Jonathan and van den Bosch, Frank C. and Green, Sheridan B. and Hopkins, Philip F. and Benson, Andrew and Du, Xiaolong (2020) SatGen: a semi-analytical satellite galaxy generator -- I. The model and its application to Local-Group satellite statistics. . (Unpublished)

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We present a semi-analytic model of satellite galaxies, SatGen, which can generate large samples of satellite populations for a host halo of desired mass, redshift, and assembly history. The model combines dark-matter halo merger trees, empirical relations for the galaxy-halo connection, and analytic prescriptions for tidal effects, dynamical friction, and ram pressure stripping. SatGen emulates cosmological zoom-in hydro-simulations in certain aspects. Satellites can reside in cored or cuspy DM subhaloes, depending on the halo response to baryonic physics that can be formulated from hydro-simulations and physical modeling. The subhalo profile and the stellar mass and size of a satellite evolves depending on its tidal mass loss and initial structure. The host galaxy can include a baryonic disc and a stellar bulge, each described by a density profile that allows analytic orbit integration. SatGen complements simulations by propagating the effect of halo response found in simulated field galaxies to satellites (not properly resolved in simulations) and outperforms simulations by sampling the halo-to-halo variance of satellite statistics and overcoming artificial disruption due to insufficient resolution. As a first application, we use the model to study satellites of Milky Way sized hosts, making it emulate simulations of bursty star formation and of smooth star formation, respectively, and to experiment with a disc potential in the host halo. Our model reproduces the observed satellite statistics reasonably well. Different physical recipes make a difference in satellite abundance and spatial distribution at the 25% level, not large enough to be distinguished by current observations given the halo-to-halo variance. The MW disc depletes satellites by 20% and has a subtle effect of diversifying the internal structure of satellites, important for alleviating certain small-scale problems. We discuss the conditions for a massive satellite to survive in MW/M31.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Dekel, Avishai0000-0003-4174-0374
Hopkins, Philip F.0000-0003-3729-1684
Benson, Andrew0000-0001-5501-6008
Additional Information:The authors are thankful to Yuval Birnboim, Timothy Carleton, Nicolas Cournuault, AndrewEmerick, Omri Ginzburg, Sharon Lapiner, Mariangela Lisanti, Lina Necib, Jacob Shen, Oren Slone, and Coral Wheeler for helpful discussions. FJ is supported by the Israeli Planning and Budgeting Committee (PBC) Fellowship, and by the Troesh Fellowship from the California Institute of Technology. FJ is thankful to Jo Bovy for publicly sharing his code design wisdom through the software galpy. FCvdB is supported by the National Aeronautics and Space Administration through Grant Nos. 17-ATP17-0028 and 19-ATP19-0059 issued as part of the Astrophysics Theory Program, and received addition support from the Klaus Tschira foundation. SBG is supported by the US National Science Foundation Graduate Research Fellowship under Grant No. DGE-1752134.
Group:Astronomy Department, TAPIR
Funding AgencyGrant Number
Israeli Committee for Planning and BudgetingUNSPECIFIED
Troesh Family Distinguished Scholars FundUNSPECIFIED
Klaus Tschira FoundationUNSPECIFIED
NSF Graduate Research FellowshipDGE-1752134
Subject Keywords:galaxies: dwarf – galaxies: evolution – galaxies: haloes – galaxies: interactions – galaxies: structure – methods: numerical
Record Number:CaltechAUTHORS:20200626-150127283
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104102
Deposited By: George Porter
Deposited On:29 Jun 2020 14:19
Last Modified:29 Jun 2020 14:19

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