The Location and Environments of Neutron Star Mergers in an Evolving Universe

Journal Article · 18 September 2018 · The Astrophysical Journal (Online)

DOI: https://doi.org/10.3847/1538-4357/aad2d4 · OSTI ID:1481979

Wiggins, Brandon Kerry  ^[1]; Fryer, Christopher Lee  ^[2]; Smidt, Joseph M.  ^[2]; Hartmann, Dieter  ^[3]; Lloyd-Ronning, Nicole  ^[2]; Belcynski, Chris ^[4]

---

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Southern Utah Univ., Cedar City, UT (United States). Dept. of Physical Science
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
3. Clemson Univ., SC (United States). Dept. of Physics and Astronomy
4. Polish Academy of Sciences, Warsaw (Poland). Nicolaus Copernicus Astronomical Center

The simultaneous detection of gravitational and electromagnetic waves from a binary neutron star merger has both solidified the link between neutron star mergers and short-duration gamma-ray bursts (GRBs), and demonstrated the ability of astronomers to follow-up the gravitational wave detection to place constraints on the ejecta from these mergers, as well as the nature of the GRB engine and its surroundings. As the sensitivity of aLIGO and VIRGO increases, it is likely that a growing number of such detections will occur in the next few years, leading to a sufficiently large number of events to constrain the populations of these GRB events. While long-duration GRBs originate from massive stars and thus are located near their stellar nurseries, binary neutron stars may merge on much longer timescales, and thus may have had time to migrate appreciably. The strength and character of the electromagnetic afterglow emission of binary neutron star mergers is a sensitive function of the circum-merger environment. Though the explosion sites of short GRBs have been explored in the literature, the question has yet to be fully addressed in its cosmological context. We present cosmological simulations following the evolution of a galaxy cluster, including star formation combined with binary population synthesis models, to self-consistently track the locations and environmental gas densities of compact binary merger sites throughout the cosmic web. In conclusion, we present probability distributions for densities as a function of redshift and discuss model sensitivity to population synthesis model assumptions.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1481979
• Report Number(s): LA-UR-18-20312
• Journal Information: The Astrophysical Journal (Online), Vol. 865, Issue 1; ISSN 1538-4357
• Publisher: Institute of Physics (IOP)Copyright Statement
• Country of Publication: United States
• Language: English