2018/05/31 by Mandy C. Chen, Tom Broadhurst, Jeremy Lim +4
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Brightest cluster galaxy #Dark matter #Einstein radius #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Gravitational lens #RADIUS #Spiral galaxy #Supermassive black hole #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/aad17b
published as The Astrophysical Journal, 863:135 (24pp), 2018 August 20 · Published version
openalex created_date 2018/05/17 · openalex publication_date 2018/08/17 · arxiv created 2018/08/20 · arxiv updated 2018/08/21 · openalex updated_date 2026/08/06
Abstract At cosmological distances, gravitational lensing can in principle provide direct mass measurements of supermassive black holes (SMBHs). Here, we directly estimate the mass of a SMBH in the brightest cluster galaxy (BCG) of MACS J1149.5+2223 at z = 0.54 using one of the multiply lensed images of a background spiral galaxy at z = 1.49 projected close to the BCG. A lensed arc is curved toward the BCG center, corresponding to an intrinsically compact region in one of the spiral arms. This arc has a radius of curvature of only ∼0.″6, betraying the presence of a local compact deflector. Its curvature is most simply reproduced by a point-like object with a mass of , similar to SMBH masses in local elliptical galaxies having comparable luminosities. The SMBH is noticeably offset by 4.4 ± 0.3 kpc from the BCG light center, which is plausibly the result of a kick imparted ∼2.0 × 10 7 years ago during the merger of two SMBHs, placing it just beyond the stellar core. A similar curvature can be produced by replacing the offset SMBH with a compact galaxy having a mass of ∼2 × 10 10 M ⊙ within a cutoff radius of <4 kpc, and an unusually large to make it undetectable in the deep Hubble Frontiers Fields image, at or close to the cluster redshift. However, such a lensing galaxy perturbs the adjacent lensed images in an undesirable way.