Revisiting the Supermassive Black Hole Mass of NGC 7052 Using High Spatial Resolution Molecular Gas Observed with ALMA

Abstract We present our dynamical mass constraints on the central supermassive black hole (SMBH) in the early-type galaxy NGC 7052 using high spatial-resolution observations of 12 CO(2–1) emission from the Atacama Large Millimeter/submillimeter Array (ALMA). The data were obtained during ALMA Cycle 7 and have a synthesized beam size of 0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi>.</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>″</mml:mi> </mml:mrow> </mml:mover> </mml:math> 29 ×0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi>.</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>″</mml:mi> </mml:mrow> </mml:mover> </mml:math> 22 (97 × 73 pc 2 ). The dynamical model yielded an SMBH mass of ≈(2.50 ±0.37 [statistical] ± 0.8 [systematic]) × 10 9 M ⊙ and a stellar I- band mass-to-light ratio of ≈4.08 ±0.23 [statistical] ± 0.4 [systematic] M ⊙ / L ⊙ , I (3 σ confidence intervals). Although our new ALMA observation has three times lower spatial resolution than previous ALMA data, it still resolves the SMBH’s sphere of influence with a spatial resolution that is 1.5 times smaller than this sphere radius. While our M BH estimate is fully consistent with the previous determination, the I -band mass-to-light ratio is lower by 10%. This difference arises from our improved galaxy mass model, which incorporates both the molecular gas distribution and the extended stellar mass in the outer regions of the galaxy, the components that were previously neglected.