Distance and Properties of NGC 4993 as the Host Galaxy of the Gravitational-wave Source GW170817

作者：Im Myungshin^*; Yoon Yongmin; Lee Seong Kook J; Lee Hyung Mok; Kim Joonho; Lee Chung Uk; Kim Seung Lee; Troja Eleonora; Choi Changsu; Lim Gu; Ko Jongwan; Shim Hyunjin

来源：Astrophysical Journal Letters, 2017, 849(1): L16.

DOI：10.3847/2041-8213/aa9367

• galaxies: elliptical and lenticular, cD
• galaxies: fundamental parameters
• galaxies: individual (NGC 4993)
• gravitational waves

Recently, the optical counterpart of the gravitational-wave source GW170817 has been identified in the NGC 4993 galaxy. Together with evidence from observations in electromagnetic waves, the event has been suggested as a result of a merger of two neutron stars (NSs). We analyze the multi-wavelength data to characterize the host galaxy property and its distance to examine if the properties of NGC 4993 are consistent with this picture. Our analysis shows that NGC 4993 is a bulge-dominated galaxy with r(eff) similar to 2-3 kpc and a Sersic index of n = 3-4 for the bulge component. The spectral energy distribution from 0.15 to 24 mu m indicates that this galaxy has no significant ongoing star formation, a mean stellar mass of (0.3-1.2) x 10(11) M-circle dot, a mean stellar age greater than similar to 3 Gyr, and a metallicity of about 20%-100% of solar abundance. Optical images reveal dust lanes and extended features that suggest a past merging activity. Overall, NGC 4993 has characteristics of normal, but slightly disturbed elliptical galaxies. Furthermore, we derive the distance to NGC 4993 with the fundamental plane relation using 17 parameter sets of 7 different filters and the central stellar velocity dispersion from the literature, finding an angular diameter distance of 37.7 +/- 8.7 Mpc. NGC 4993 is similar to some host galaxies of short gamma-ray bursts (GRBs) but much different from those of long GRBs, supporting the picture of GW170817 as a result of the merger of two NSs.

• 出版日期2017-11-1