SEVN BENCHMARK2401 This repository contains the data products of the SEVN runs "Benchmark2014". In particular, the datasets contain the population of binary compact objects (BCOs, Black holes, BHs, and Neutron stars, NSs) obtained simulating 40 milion binaries (divided in the two equivalent, a part for the initial conditions, datasets) with the rapid poulation syntehsis code SEVN (Iorio+23, version 2.7.5). The BCOs stored in the files are solely the one that will merge within an Hubble time (14 Gyr). Repository content README.md: this file is a copy of this same Zenodo description SEVN_input.tar: this archive contains the scripts used to generate the initial conditions and to estimate the total simulated mass (corrected for incomplete mass sampling; see below). It also includes the run script used to execute the simulations, with all SEVN parameters specified. bcom_scighera2401.tar.gz: archive containing the BCOs of the scighera2401 dataset (results from the run of 20 million binaries). bcom_leonardo2401.tar.gz: archive containing the BCOs of the leonardo2401 dataset (results from the run of 20 million binaries). Using this dataset If you find this dataset useful for your work, you are welcome to use the entire dataset or any part of it.If you make use of the data in a published work, please include the following citations: This Zenodo repository The main SEVN paper, Iorio+23 (https://ui.adsabs.harvard.edu/abs/2023MNRAS.524..426I/abstract), plus the two foundational papers: Mapelli+20 (https://ui.adsabs.harvard.edu/abs/2020ApJ...888...76M/abstract), Spera+19 (https://ui.adsabs.harvard.edu/abs/2019MNRAS.485..889S/abstract). In addition, you may cite Marinacci+25 (https://arxiv.org/abs/2510.06311), which provides a description of the SEVN runs and initial conditions. The Dataset The datasets contains the BCOs obtained running SEVN (Iorio+23, version 2.7.5). to simulate a total of 40 milion binaries split in two datasets: leonardo2401: set of simulations run on the leonardo hpc @ cineca. The initial condition includes 20 milion binaries for a total mass of $`M_\mathrm{sim}=442538939.33`$ Msun. scighera2401: set of simulations run on the scighera @ fiscia.unipd. The initial condition includes20 milion binaries for a total mass of $`M_\mathrm{sim}=442648579.81`$ Msun. For each simulation set, we generate a single initial condition (IC) file (see below) and evolve the binaries for 15 different metallicities ZZ (mass fraction of metals):0.0001, 0.0002, 0.0004, 0.0006, 0.0008, 0.001, 0.002, 0.004, 0.006, 0.008, 0.01, 0.014, 0.017, 0.02, and 0.03. All other SEVN parameters are fixed to their default values for version version 2.7.5) These parameter values can be found in the run script included in the dataset archives or in the SEVN input archive. Important Note. The two datasets are compatible and complementary, as they were generated using the same SEVN version and identical SEVN and sampling parameters (although the initial condition samplings are independent).You can use either dataset individually or combine several (considering the different metallicities) of them (or even all), including subsamples from specific datasets, depending on your needs. Initial Conditions The initial conditions were generated with the code IC4popsyn(commit version a24c6e60d19f5b37ccab659baa06efb02f261865), using the following prescriptions: The primary mass follows a Kroupa (2001) initial mass function (IMF)m−2.35m−2.35 between 5 and 150 M⊙. The mass ratio q=m2/m1q=m2/m1 follows the power law from Sana et al. (2012),q−0.1q−0.1, with qq between qmin=min⁡(2.2/m1,0.1)qmin=min(2.2/m1,0.1) and 1.With this choice, the secondary mass is always ≥ 2.2 M⊙. The logarithm of the orbital period, P=log⁡(P/days)P=log(P/days), follows a power law from Sana et al. (2012),P−0.55P−0.55, with PP between 0.33 and 5.5. The initial eccentricity follows a power law from Sana et al. (2012),e−0.42e−0.42, with ee between 0 and 0.9. The eccentricity–period correlation correction from Moe & Di Stefano (2017) (their Eq. 3) has been applied. The initial conditions can be generated using the script generate_IC.py in SEVN_input.tar Correction Factors for the Total Mass Due to the incomplete sampling of the mass function, the total mass of the parent stellar population represented by the simulations is given by where: Mpop = Msim/(fIMF*fbin) Msim is the total mass of the simulated binaries (including both primary and secondary stars); fIMF accounts for the fraction of the IMF actually sampled; fbin represents the fraction of stellar mass in binaries(e.g. fbin=0.2 means that 20 % of the total mass is in binary systems). Kroupa IMF Considering the cuts applied in generating the initial conditions, we obtain: fIMF=0.251 fbin can be freely chosen.If one adopts the binary fraction as a function of primary mass from Moe & Di Stefano (2017),this corresponds to an effective fbin=0.569 The mass correction factor can be estimated using the script estimate_mass_correction.py Chabrier IMF with limit at M=100 Msun In one of the paper that used the dataset (Marinacci+25), a Chabrier with a limit mass at 100 Msun was assumed. In order to correct for the different mass range: - Remove from the bco file all the systems with Mzams_0>100 Msu - A new correction factor must be included to estimate the popolation total mass. The current total mass of the IC subpopulations with MCE) used in the simulation. BWorldtime: [float, Myr] Age of the system at the time of binary compact object formation (0 = start of the simulation). Mass_0, Mass_1: [float, M⊙] Masses of the compact remnants. Radius_0, Radius_1: [float, R⊙] Radii of the compact remnants. Zams_0, Zams_1: [float, M⊙] ZAMS mass of the last interpolated SEVN track used for the star (not the progenitor’s initial ZAMS mass). Mzams_0, Mzams_1: [float, M⊙] True ZAMS masses of the progenitors. Phase_0, Phase_1: [int] Stellar evolutionary phase (always 7 for compact remnants). RemnantType_0, RemnantType_1: [int] Compact remnant type: –1: massless (not present) 0: not a remnant (not present) 1: HeWD (not present) 2: COWD (not present) 3: ONeWD (not present) 4: ECNS — neutron star formed via electron-capture SN 5: CCNS — neutron star formed via core-collapse SN 6: black hole Xspin_0, Xspin_1: [float] Dimensionless spin parameter of the BH (NaN for NSs). Semimajor: [float, R⊙] Semi-major axis at the moment of binary compact object formation. Eccentricity: [float] Eccentricity at the moment of binary compact object formation. GWtime: [float, Myr] Time to merge via gravitational-wave emission. Semimajor_ini, Eccentricity_ini: [float] Initial orbital parameters (at simulation start). NSt, NSu: [int] Number of stripped and ultra-stripped supernova explosions, respectively. channel: [int] Binary interaction channel: 0 — no interactions (RLO or CE) 1 — stable mass transfer before the first SN, then CE 2 — only stable mass transfer episodes 3 — at least one CE before the first SN; at that moment the system hosts an H-star and a pure-He/naked-CO star 33 — same as 3 but with a single-core CE 4 — at least one CE before the first SN; at that moment both stars are pure-He/naked-CO 44 — same as 4 but with a double-core CE 5 — no interactions before the first SN subchannel: [char] Evolution after the first SN: n — no interactions s — only stable mass transfer episodes c — one CE d — more than one CE collisions: [int] Number of periastron collisions triggered during binary evolution outside RLO phases. CE, CEb, CEa: [int] Number of common-envelope (CE) events in total, before, and after the first SN. SMTa: [int] Number of stable mass transfer episodes after the first SN. Events, EventsSimple, EventsPlus, EventsAll: [str] Encoded sequences of the main evolutionary events of the BCO progenitors. SNtime_0/1, SNMej_0/1, SNvcom_0/1, SNcalpha_0/1, SNtype_0/1: Information on the supernova explosions of each star, including explosion time, ejected mass, post-SN velocity, angular momentum alignment, and SN type.SNtype codes: 0 — Unknown 1 — Electron-capture SN 2 — Core-collapse SN 3 — Pulsational pair-instability SN 4 — Pair-instability SN 5 — SN Ia Warnings Warning-1: NaN valuesNaN values are legitimate in SEVN outputs. In these files, they should appear only in the columns Xspin_0 and Xspin_1. Warning-2: _0 and _1 suffixesThe suffixes _0 and _1 indicate the position of the star in the initial conditions file.They do not correspond to the most or least massive component at any stage.However, by construction, star _0 is always the initially more massive one. Warning-3: Uniquely identifying a systemAll simulations use identical initial conditions with the same random seed; therefore, IDs and names may repeat.To uniquely identify a system, use the combination of the four columns: ID, name, alpha, and Z.For this dataset, either ID or name can be used interchangeably, but alpha and Z are still required. Warning-4: Initial mass of BH/NS progenitorsThe progenitor’s true initial ZAMS mass is stored in Mzams_0 and Mzams_1.Do not use Zams_0 and Zams_1. Reading the Events The event columns (Events, EventsSimple, EventsPlus, EventsAll) list, in chronological order, the main evolutionary events of the BCO progenitors.Each event is separated by a colon (:).The following describes the possible event keys used in each column. Column: Events Keys RB – RLO begins RC – Circularisation at the onset of RLO RE – RLO ends K – Collision at periastron C – Common envelope S – Supernova explosion Column: EventsPlus Keys RB, RC, RE, K – Same meaning as above Cs – Single-core CE (only one star has a core) Cse – Single-core CE triggered by a pure-He star Cd – Double-core CE (both stars have a core) Cde – Double-core CE triggered by a pure-He star ijSx – Supernova explosion, where: i/j indicate the exploding star and its companion: h — hydrogen star e — pure-He or naked-CO star r — compact remnant x indicates the SN type: t — stripped SN (pure-He progenitor) u — ultra-stripped SN (naked-CO progenitor) (empty) — classical SN Column: EventsAll Same as EventsPlus, but with additional detail for RLO onset: RBkjc: RLO begins, where k = 0 → star 0 is donor, k = 1 → star 1 is donor j = evolutionary phase of the donor: 1 = main sequence 2 = terminal-age main sequence 3 = shell H-burning 4 = core He-burning 5 = terminal-age core He-burning 6 = shell He-burning c = e if the donor is a pure-He star, empty otherwise Other keys are the same as in EventsPlus. Column: EventsSimple Keys M – Stable mass-transfer episode (begins and ends without CE) C – Common envelope (includes RLOs that directly trigger a CE) K – Collision at periastron directly followed by CE ijS – Supernova explosion, where i/j indicate the exploding star and its companion: h — hydrogen star e — pure-He or naked-CO star r — compact remnant