Extremely Large Telescope

Abstract:

Abstract We present high angular resolution (0.19 arcsec or ≈24 pc) Atacama Large Millimeter/submillimeter Array observations of the 12CO(3−2) line emission of the galaxy NGC 4751. The data provide evidence for the presence of a central supermassive black hole (SMBH). Assuming a constant mass-to-light ratio (M/L), we infer a SMBH mass $M_\text{BH}=3.43^{+0.45}_{-0.44}[\text{stat},\, 3\sigma ]^{+0.22}_{-0.64}[\text{sys}]\times 10^9$ M⊙ and a F160W filter stellar $M/L_{F160W}=2.68\pm 0.11[\text{stat},\, 3\sigma ]^{+0.10}_{-0.80}[\text{sys}]$ M⊙/L⊙, F160W, where the first uncertainties are statistical and the second systematic. Assuming a linearly spatially-varying M/L, we infer $M_\text{BH}=2.79^{+0.75}_{-0.57}[\text{stat},\, 3\sigma ]^{+0.75}_{-0.45}[\text{syst}]\times 10^9$ M⊙ and $\left(M/L_\text{F160W}\right)/\left(\text{M}_\odot /\text{L}_{\odot ,\text{F160W}}\right)=3.07^{+0.27}_{-0.35}[\text{stat},\, 3\sigma ]^{+0.08}_{-1.14}[\text{sys}]-0.09^{+0.08}_{-0.06}[\text{stat},\, 3\sigma ]^{+0.08}_{-0.01}[\text{sys}]\, \left(R/\text{arcsec}\right)$, where R is the galactocentric radius. We also present SMBH mass estimates using the Jeans Anisotropic Modelling (JAM) method and Very Large Telescope Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI) stellar kinematics. Assuming a cylindrically-aligned velocity ellipsoid (JAMcyl) we infer MBH = (2.52 ± 0.36) × 109 M⊙, while assuming a spherically-aligned velocity ellipsoid (JAMsph) we infer MBH = (3.24 ± 0.87) × 109 M⊙. The SMBH mass assuming a constant M/L is statistically consistent with that of JAMsph, whereas the mass assuming a linearly-varying M/L is consistent with both JAMcyl and JAMsph (within the uncertainties). Our derived masses are larger than (and inconsistent with) one previous stellar dynamical measurement using the Schwarzschild orbit-superposition method and the same SINFONI kinematics.

Abstract:

Understanding the demographics of intermediate-mass black holes (IMBHs, MBH ≈ 102–105 M⊙) in low-mass galaxies is key to constraining black hole seed formation models, but detecting them is challenging due to their small gravitational sphere of influence (SOI). The upcoming Extremely Large Telescope (ELT) High Angular Resolution Monolithic Optical and Near-infrared Integral Field Spectrograph (HARMONI) instrument, with its high angular resolution, offers a promising solution. We present simulations assessing HARMONI’s ability to measure IMBH masses in nuclear star clusters (NSCs) of nearby dwarf galaxies. We selected a sample of 44 candidates within 10 Mpc. For two representative targets, NGC 300 and NGC 3115 dw01, we generated mock HARMONI integral-field data cubes using realistic inputs derived from Hubble Space Telescope imaging, stellar population models, and Jeans anisotropic models (JAM), assuming IMBH masses up to 1% of the NSC mass. We simulated observations across six near-infrared gratings at 10 mas resolution. Analyzing the mock data with standard kinematic extraction and JAM models in a Bayesian framework, we demonstrate that HARMONI can resolve the IMBH SOI and accurately recover masses down to ≈0.5% of the NSC mass within feasible exposure times. These results highlight HARMONI’s potential to revolutionize IMBH studies.

Abstract:

We analyse the ro-vibrational absorption bands of various molecular cations (HCO, HCNH, and NH) and neutral species (HCN, HNC, and HCN) detected in the James Webb Space Telescope/Mid-Infrared Instrument Medium Resolution Spectrometer spectrum (4.9–27.9 μm) of the local ultraluminous infrared galaxy IRAS 07251-0248. We find that the molecular absorptions are blueshifted by 160 km s relative to the systemic velocity of the target. Using local thermal equilibrium excitation models, we derive rotational temperatures () from 42 to 185 K for these absorption bands. This range of measured can be explained by infrared radiative pumping as a by-product of the strength, effective critical density, and opacity of each molecular band. Thus, these results suggest that these absorptions originate in a warm expanding gas shell (90–330 yr), which might be the base of the larger scale cold molecular outflow detected in this source. Finally, the elevated abundance of molecular cations can be explained by a high cosmic ray ionization rate, with log(/n in the range of -18.2 (from H) to -19.1 (inferred from HCO and NH, which are likely tracing denser gas), consistent with a cosmic ray dominated chemistry as predicted by chemical models.

Abstract:

We present a new measurement of the dark and luminous matter distribution of massive elliptical galaxies, and their evolution with redshift, by combining strong lensing and dynamical observables. Our sample of 56 lens galaxies covers a redshift range of . By combining new Hubble Space Telescope imaging with previously observed velocity dispersion and line-of-sight measurements, we decompose the luminous matter profile from the dark matter profile and perform a Bayesian hierarchical analysis to constrain the population-level properties of both profiles. We find that the inner slope of the dark matter density profile (‘cusp’; ) is consistent ( with intrinsic scatter) with a standard Navarro–Frenk–White (NFW; ) at . Additionally, we find an appreciable evolution with redshift () resulting in a shallower slope (of tension from NFW) at redshifts . This is in excellent agreement with previous population-level observational studies, as well as with predictions from hydrodynamical simulations such as IllustrisTNG. We also find the stellar mass-to-light ratio at the population level is consistent with that of a Salpeter initial mass function, a small stellar mass-to-light gradient [, with ], and isotropic stellar orbits. Our averaged total mass density profile is consistent with a power-law profile within 0.25 to 4 Einstein radii (), with an internal mass-sheet transformation parameter consistent with no mass sheet. Our findings confirm the validity of the standard mass models used for time-delay cosmography.