A Broad HCO<sup>+</sup> Absorption Line Associated with the Circumnuclear Torus of NGC 1052

Sawada-Satoh, Satoko; Byun, Do-Young; Lee, Sang-Sung; Oh, Se-Jin; Roh, Duk-Gyoo; Kameno, Seiji; Yeom, Jae-Hwan; Jung, Dong-Kyu; Oh, Chungsik; Kim, Hyo-Ryoung; Hwang, Ju-Yeon

doi:10.3847/2041-8213/ab0425

Cited by 9 publications

(1 citation statement)

References 38 publications

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“…The HCO + J = 1−0 feature is partially covered by our spectral setting. The ratio of the HCN-to-HCO + peak opacity is 2.1 ± 0.2, being consistent with the Korean VLBI Network (KVN) results (Sawada-Satoh et al 2019).…”

Section: Observations and Resultssupporting

confidence: 89%

Probing the Jet–Torus Interaction in the Radio Galaxy NGC 1052 by Sulfur-bearing Molecules

Kameno

Sawada-Satoh²,

Impellizzeri

et al. 2023

ApJ

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The radio galaxy NGC 1052 casts absorption features of sulfur-bearing molecules, H2S, SO, SO2, and CS toward the radio continuum emission from the core and jets. Using the Atacama Large Millimeter/submillimeter Array, we have measured the equivalent widths of SO absorption features in multiple transitions and determined the temperatures of 344 ± 43 K and 26 ± 4 K in submillimeter and millimeter wavelengths, respectively. Since submillimeter and millimeter continuum represents the core and jets, the high and low temperatures of the absorbers imply a warm environment in the molecular torus and cooler downstream flows. The high temperature in the torus is consistent with the presence of 22 GHz H2O maser emission, vibrationally excited HCN and HCO+ absorption lines, and sulfur-bearing molecules in the gas phase released from dust. The origin of the sulfur-bearing gas is ascribed to the evaporation of the icy dust component through a jet–torus interaction. Shock heating is the sole plausible mechanism to maintain such a high temperature of gas and dust in the torus. The implication of the jet–torus interaction also supports the collimation of the sub-relativistic jets by the gas pressure of the torus.

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Section: Observations and Resultssupporting

confidence: 89%

Probing the Jet–Torus Interaction in the Radio Galaxy NGC 1052 by Sulfur-bearing Molecules

Kameno

Sawada-Satoh²,

Impellizzeri

et al. 2023

ApJ

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ALMA detection of 321 GHz water maser emission in the radio galaxy NGC 1052

Kameno

Harikane

Sawada-Satoh³

et al. 2023

Publications of the Astronomical Society of Japan

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The Atacama Large Millimeter/submillimeter Array (ALMA) serendipitously detected H2O $J_{K_{\rm a}, K_{\rm c}} = 10_{2,9}$–93, 6 emission at 321 GHz in NGC 1052. This is the first submillimeter maser detection in a radio galaxy and the most luminous 321 GHz H2O maser known to-date with the isotropic luminosity of $1090\, L_{\odot }$. The line profile consists of a broad velocity component with FWHM = 208 ± 12 km s−1 straddling the systemic velocity and a narrow component with FWHM = 44 ± 3 km s−1 blueshifted by 160 km s−1. The profile is significantly different from the known 22 GHz 61, 6–52, 3 maser which shows a broad profile redshifted by 193 km s−1. The submillimeter maser is spatially unresolved with a synthesized beam of ${0{^{\prime \prime}_{.}}68} \times {0{^{\prime \prime}_{.}}56}$ and coincides with the continuum core position within 12 pc. These results indicate amplification of the continuum emission through high-temperature (>1000 K) and dense [n(H2O) > 104 cm−3] molecular gas in front of the core.

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Very long baseline interferometry imaging of H2O maser emission in the nearby radio galaxy NGC 4261

Sawada-Satoh¹,

Kawakatu

Niinuma

et al. 2023

Publications of the Astronomical Society of Japan

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We report dual-frequency very long baseline interferometry (VLBI) observations at 22 and 43 GHz toward the nucleus of a nearby radio galaxy NGC 4261. In particular, we present a VLBI image of the 22 GHz H2O maser line and its location in the circumnuclear region of NGC 4261. H2O maser emission is marginally detected above the three times the image rms level at channels within a velocity range of approximately 2250–2450 km s−1, slightly red-shifted with respect to the systemic velocity. H2O maser emission is located approximately 1 milliarcsecond east of the brightest continuum component at 22 GHz, where the continuum spectrum is optically thick, that is, at the free–free absorbed receding jet by ionized gas. A positional coincidence between H2O maser emission and an ionized gas disk implies that the H2O maser emission arises from the near side of the disk, amplifying continuum emission from the background receding jet. If the disk axis is oriented 64° relative to the line of sight, the H2O maser emission is expected to be at a mean radius of 0.3 pc in the disk. The broad line width of the H2O maser emission can be attributed to complex kinematics in the immediate vicinity of the supermassive black hole (SMBH), including ongoing gas infall on to the SMBH, turbulence, and outflow. This is analogous to the multi-phase circumnuclear torus model in the nearest radio-loud H2O megamaser source NGC 1052. An alternative explanation for H2O maser association is the shock region between the jet and ambient molecular clouds. However, this explanation fails to describe the explicit association of H2O maser emission only with the free–free absorbed receding jet.

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A Broad HCO⁺ Absorption Line Associated with the Circumnuclear Torus of NGC 1052

Cited by 9 publications

References 38 publications

Probing the Jet–Torus Interaction in the Radio Galaxy NGC 1052 by Sulfur-bearing Molecules

Probing the Jet–Torus Interaction in the Radio Galaxy NGC 1052 by Sulfur-bearing Molecules

ALMA detection of 321 GHz water maser emission in the radio galaxy NGC 1052

Very long baseline interferometry imaging of H2O maser emission in the nearby radio galaxy NGC 4261

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A Broad HCO+ Absorption Line Associated with the Circumnuclear Torus of NGC 1052

Cited by 9 publications

References 38 publications

Probing the Jet–Torus Interaction in the Radio Galaxy NGC 1052 by Sulfur-bearing Molecules

Probing the Jet–Torus Interaction in the Radio Galaxy NGC 1052 by Sulfur-bearing Molecules

ALMA detection of 321 GHz water maser emission in the radio galaxy NGC 1052

Very long baseline interferometry imaging of H2O maser emission in the nearby radio galaxy NGC 4261

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A Broad HCO⁺ Absorption Line Associated with the Circumnuclear Torus of NGC 1052