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This content will become publicly available on December 18, 2018

Title: Improved Constraints on H 0 from a Combined Analysis of Gravitational-wave and Electromagnetic Emission from GW170817

The luminosity distance measurement of GW170817 derived from gravitational-wave analysis in Abbott et al. (2017a, hereafter A17:H0) is highly correlated with the measured inclination of the NS–NS system. To improve the precision of the distance measurement, we attempt to constrain the inclination by modeling the broadband X-ray-to-radio emission from GW170817, which is dominated by the interaction of the jet with the environment. We update our previous analysis and we consider the radio and X-ray data obtained at t < 40 days since merger. We find that the afterglow emission from GW170817 is consistent with an off-axis relativistic jet with energy E k~10 48 -3 × 10 50 erg propagating into an environment with density n ~ 10 -2–10-4 cm-3, with preference for wider jets (opening angle θ j = 15°). For these jets, our modeling indicates an off-axis angle θ obs ~25°–50°. We combine our constraints on θ obs with the joint distance–inclination constraint from LIGO. Using the same ~170 km s -1 peculiar velocity uncertainty assumed in A17:H0 but with an inclination constraint from the afterglow data, we get a value of H 0 =74.0 ± $$\frac{11.5}{7.5}$$ km s -1 Mpc -1, which is higher than the value of H 0 70.0 ± $$\frac{12.0}{8.0}$$ km s -1 Mpc -1 found in A17:H0. Further, using a more realistic peculiar velocity uncertainty of 250 km s -1 derived from previous work, we find km s -1 Mpc -1 for H 0 from this system. This is in modestly better agreement with the local distance ladder than the Planck cosmic microwave background, though such a significant discrimination will require ~50 such events. Finally, measurements at t > 100 days of the X-ray and radio emission will lead to tighter constraints.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [3] ;  [4] ; ORCiD logo [2] ; ORCiD logo [5] ; ORCiD logo [1] ; ORCiD logo [6] ; ORCiD logo [5] ;  [5] ;  [7] ;  [2] ;  [5] ;  [8] ; ORCiD logo [9] ; ORCiD logo [5] ; ORCiD logo [10] ; ORCiD logo [2] ; ORCiD logo [5] ; ORCiD logo [5]
  1. Univ. of Ferrara (Italy). Dept. of Physics and Earth Science
  2. Northwestern Univ., Evanston, IL (United States). Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Dept. of Physics and Astronomy
  3. Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Physics and Astronomy
  4. Univ. of Chicago, IL (United States). Enrico Fermi Inst., Dept. of Physics, Dept. of Astronomy and Astrophysics
  5. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
  6. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  7. Ohio Univ., Athens, OH (United States). Astrophysical Inst., Dept. of Physics and Astronomy
  8. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Univ. of Chicago, IL (United States). Dept. of Astronomy and Astrophysics
  9. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Physics
  10. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Brandeis Univ., Waltham, MA (United States). Dept. of Physics
Publication Date:
Report Number(s):
FERMILAB-PUB-17-469-A; arXiv:1710.06426
Journal ID: ISSN 2041-8213; 1631149
Grant/Contract Number:
AC02-07CH11359
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal. Letters
Additional Journal Information:
Journal Volume: 851; Journal Issue: 2; Journal ID: ISSN 2041-8213
Publisher:
Institute of Physics (IOP)
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; gamma-ray burst: general; gravitational waves
OSTI Identifier:
1434943