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We present the results of our ALMA Cycle 4 high-spatial-resolution (0.04-0.07") observations, at HCN J=3-2 and HCO+ J=3-2 lines, of the nucleus of NGC 1068, the nearby prototypical type 2 active galactic nucleus (AGN). Our previous ALMA observations identified the compact emission of these lines at the putative location of the torus around a mass-a...
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... 07), we conducted shorter baseline observations to recover ∼1 ′′ scale spatially extended diffuse emission. Table 1 summarizes our observational details. We combined our Cycle 4 data with our ALMA Cycle 2 0. ′′ 1-0. ...
Context 2
... created cleaned images by using (a) Cycle 4 longest baseline data only (dubbed as "H1" in Table 1) and (b) Cycle 2 and all Cycle 4 data. We achieved a smaller spatial resolution for (a), but recovered a larger amount of molecular emission from the central several arcsec region of the host galaxy from (b). ...
Citations
... Molecular observations of the gas enveloping AGNs have uncovered a intricate scenario in which the observational signatures of mechanical and radiative feedback are confounded by the probable existence of starburst activity [54][55][56][57]. Galaxies exhibiting both an AGN and robust circumnuclear star formation are particularly intriguing, as they encompass a intricate amalgamation of energetic processes, such as gas accretion and external infall, which contribute to a complex geometry and kinematics [58][59][60]. These combined factors give rise to a multifaceted and dynamic system. ...
This review examines the relationship between black hole activity and kinematic gas–star misalignment in brightest group galaxies (BGGs) with different merger rates. The formation history of galaxy groups is assessed through “age-dating” as an indicator of distinct major mergers involving the BGGs. BGGs within groups characterized by a higher frequency of major mergers are more likely to host active SMBHs. A consistent correlation is identified between the level of black hole activity, as indicated by the 1.4 GHz and 325 MHz radio emissions, and the degree of kinematic misalignment between the gas and stellar components in BGGs. In dynamically fossil groups, where black hole accretion rate is relatively (∼1 dex) lower due to the lack of recent (≤1 Gyr) major mergers, there is reduced (∼30%) misalignment between the gas and stellar components of BGGs compared to non-fossil groups. Additionally, this study reveals that BGGs in non-fossil groups show higher levels of star formation rate and increased occurrence of mergers, contributing to observed color differences. Exploring the properties and dynamics of the gas disk influenced by mechanical AGN feedback through hydrodynamic simulations suggests that AGN wind-induced effects further lead to the persistent gas misalignment in the disk around the supermassive black hole.
... Molecular observations of the gas enveloping AGNs have uncovered a intricate scenario in which the observational signatures of mechanical and radiative feedback are confounded by the probable existence of starburst activity [52][53][54][55]. Galaxies exhibiting both an AGN and robust circumnuclear star formation are particularly intriguing, as they encompass a intricate amalgamation of energetic processes, such as gas accretion and external infall, which contribute to a complex geometry and kinematics [56][57][58]. These combined factors give rise to a multifaceted and dynamic system. ...
This review examines the relationship between blackhole activity and kinematic gas-star misalignment in brightest group galaxies (BGGs) with different merger rates. The formation history of galaxy groups is assessed through "age-dating" as an indicator of distinct major mergers involving the BGG. BGGs within groups characterized by a higher frequency of major mergers are more likely to host active SMBHs. A consistent correlation is identified between the level of black hole activity, as indicated by the 1.4 GHz and 325 MHz radio emissions, and the degree of kinematic misalignment between the gas and stellar components in BGGs. In dynamically relaxed groups, where blackhole accretion rate is relatively (∼1 dex) lower due to the lack of recent ( ≤1 Gyr) major mergers, there is reduced (∼ 30%) misalignment between the gas and stellar components of BGGs compared to unrelaxed groups. Additionally, the study reveals that BGGs in unrelaxed groups show higher levels of star formation rate and increased occurrence of mergers, contributing to observed color differences. Exploring the properties and dynamics of the gas disc influenced by mechanical AGN feedback through hydrodynamic simulations suggests that AGN wind-induced effects further lead to persistent gas misalignment of the disk around the supermassive blackhole.
... AGN torus models (e.g., Hönig et al. 2006;Nenkova et al. 2008aNenkova et al. , 2008bSchartmann et al. 2008;Hönig & Kishimoto 2010;Stalevski et al. 2012;Siebenmorgen et al. 2015;Nikutta et al. 2021) reproduced well the mid-infrared (MIR; 7-25 μm) spectral energy distributions (SEDs) of groundbased 8 m class imaging (e.g., Radomski et al. 2003;Packham et al. 2005;Mason et al. 2006;Radomski et al. 2008;Asmus et al. 2014;Asmus 2019) and spectroscopic observations of local AGNs (e.g., Ramos Almeida et al. 2009;Alonso-Herrero et al. 2011;Ramos Almeida et al. 2011;García-Bernete et al. 2015;Ichikawa et al. 2015;García-González et al. 2017;García-Bernete et al. 2019;González-Martín et al. 2019;García-Bernete et al. 2022) and constrained the torus size to <10 pc radii. High spatial resolution Atacama Large Millimeter/submillimeter Array (ALMA) submillimeter observations have further detected the dusty molecular tori in several nearby Seyfert AGN, suggesting a molecular torus region of up to ∼30 pc radius (depending on the molecular gas tracer used; García-Burillo et al. 2016;Imanishi et al. 2016Imanishi et al. , 2018García-Burillo et al. 2019;Alonso-Herrero et al. 2021;García-Burillo et al. 2021). ...
The superb image quality, stability, and sensitivity of JWST permit deconvolution techniques to be pursued with a fidelity unavailable to ground-based observations. We present an assessment of several deconvolution approaches to improve image quality and mitigate the effects of the complex JWST point-spread function (PSF). The optimal deconvolution method is determined by using WebbPSF to simulate JWST’s complex PSF and MIRISim to simulate multiband JWST/Mid-Infrared Imager Module (MIRIM) observations of a toy model of an active galactic nucleus (AGN). Five different deconvolution algorithms are tested: (1) Kraken deconvolution, (2) Richardson–Lucy, (3) the adaptive imaging deconvolution algorithm, (4) sparse regularization with the Condat–Vũ algorithm, and (5) iterative Wiener filtering and thresholding. We find that Kraken affords the greatest FWHM reduction of the nuclear source of our MIRISim observations for the toy AGN model while retaining good photometric integrity across all simulated wave bands. Applying Kraken to Galactic Activity, Torus, and Outflow Survey (GATOS) multiband JWST/MIRIM observations of the Seyfert 2 galaxy NGC 5728, we find that the algorithm reduces the FWHM of the nuclear source by a factor of 1.6–2.2 across all five filters. Kraken images facilitate detection of extended nuclear emission ∼2.″5 (∼470 pc, position angle ≃ 115°) in the SE–NW direction, especially at the longest wavelengths. We demonstrate that Kraken is a powerful tool to enhance faint features otherwise hidden in the complex JWST PSF.
... Recent sub-mm mapping observations of thermally excited molecular emission lines in the galaxy using ALMA revealed that a parsec-scale torus structure, that surrounds the nuclear region, does not have the simple axisymmetric structure expected in the unified theory (e.g. Imanishi et al. 2018Imanishi et al. , 2020Impellizzeri et al. 2019 ). Gallimore et al. ( 1996 ) reported the presence of H 2 O maser towards radio jet component C (hereafter the 'off-nuclear maser'), which is located about 0.3 arcsec ( ∼ 20 pc) northeast from the component S1. ...
... GHz, respectively. More details of the observations, calibrations, and data analysis are described in Imanishi et al. ( 2018 ). We analysed HCO + ( J = 4-3) emission line data at 356.734 GHz (Project: 2016.1.00232.S) obtained from the ALMA science archive. ...
... 3shows the maser spectra obtained by MERLIN towards the positions of components S1 and C in the velocity range of V LSR = 800-997 km s −1 (the blueshifted velocity range), V LSR = 994-1190 km s −1 (the systemic velocity range) towards the location of the nucleus S1, and V LSR = 800-1000 km s −1 towards the radio jet component C. The peak flux density of the maser is 30 mJy beam −1 at V LSR = 865 km s −1 with a signal-to-noise ratio (SNR) of ∼5.The position of the maser at V LSR = 1162 km s −1 with a peak flux of 32 mJy beam −1 near the systemic velocity is RA = 02 h 42 m 40.7093 s , Dec. = −00 • 00 47.9479 (J2000). This coincides with the position of the AGN (RA = 02 h 42 m 40.71 s , Dec. = −00 • 00 47.94 (J2000)) reported inImanishi et al. ( 2018 ). The H 2 O maser in the nuclear region of the galaxy was searched within the field of view of 0.768 × 0.768 arcsec 2 , centred on the phase tracking centre of the galaxy and in the velocity range of V LSR = ∼ 800-1189 km s −1 . ...
The results of high-resolution spectral-line observations of dense molecular gas are presented towards the nuclear region of the type 2 Seyfert galaxy NGC 1068. MERLIN observations of the 22 GHz H2O maser were made for imaging the known off-nuclear maser emission at radio jet component located about 0.3” north-east of the radio nucleus in the galaxy. High angular resolution ALMA observations have spatially resolved the molecular gas emissions of HCN and HCO+ in this region. The off-nuclear maser spots are found to nearly overlap with a ring-like molecular gas structure and are tracing an evolving shock-like structure, which appears to be energized by interaction between the radio jet and circumnuclear medium. The scenario of the dynamic jet-ISM interaction is further supported by a systematic shift of the centroid velocities of the off-nuclear maser features over a period of 35 years. The enhanced integrated flux ratios of the HCN to HCO+ line emission features at component C suggest a kinetic temperature Tk$\gtrsim$300K and an H2 density of $\gtrsim$106 cm−3, which are conditions where water masers may be formed. The diagnostics of the masering action in this jet-ISM interaction region is exemplary for galaxies hosting off-nuclear H2O maser emission.
... We believe that our AGN spectrum is more or less contaminated, especially by the neighboring E-knot. Thus, our AGN spectrum does not originate solely from the AGN torus (García-Burillo et al. 2016; Imanishi et al. 2018Imanishi et al. , 2020. In such a case, the source size is smaller than the convolved beam size; thus, the beam-averaged integrated flux and the column density may be underestimated. ...
... There are no molecules with a higher density in the AGN position than in the E-and/or W-knots. We believe that the dense molecular torus at the AGN position, whose density may be close to that of the knot regions reported by García-Burillo et al. (2016) and Imanishi et al. (2018), is not significant in this observation. In addition, one of the reasons for the lower column densities could be the effect of the beam-filling factor (see Section 3.4). ...
We present an imaging molecular line survey in the 3 mm band (85–114 GHz) focused on one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068, based on observations taken with the Atacama Large Millimeter/submillimeter Array. Distributions of 23 molecular transitions are obtained in the central ∼3 kpc region, including both the circumnuclear disk (CND) and starburst ring (SBR) with 60 and 350 pc resolution. The column densities and relative abundances of all the detected molecules are estimated under the assumption of local thermodynamic equilibrium in the CND and SBR. Then, we discuss the physical and chemical effects of the AGN on molecular abundance corresponding to the observation scale. We found that H ¹³ CN, SiO, HCN, and H ¹³ CO ⁺ are abundant in the CND relative to the SBR. In contrast, ¹³ CO is more abundant in the SBR. Based on the calculated column density ratios of N (HCN)/ N (HCO ⁺ ), N (HCN)/ N (CN), and other molecular distributions, we conclude that the enhancement of HCN in the CND may be due to high-temperature environments resulting from strong shocks, which are traced by the SiO emission. Moreover, the abundance of CN in the CND is significantly lower than the expected value of the model calculations in the region affected by strong radiation. The expected strong X-ray irradiation from the AGN has a relatively lower impact on the molecular abundance in the CND than mechanical feedback.
... On the other hand, this also means that jets from ∼3 sBHs at ∼1 pc are directed to us, which may be problematic to be consistent with the X-ray flux from NGC 1068. This is because the X-ray emission from corona in NGC 1068 may be mostly absorbed at sub-parsec scales, instead of several parsec scales, by considering the amount of mass estimated in parsec scales (García-Burillo et al. 2016;Imanishi et al. 2018Imanishi et al. , 2020. In that case, the X-ray emission from jets at ∼1 pc may not be fully absorbed and significantly exceed the observed X-ray flux. ...
Some Seyfert galaxies are detected in high-energy gamma rays, but the mechanism and site of gamma-ray emission are unknown. Also, the origins of the cosmic high-energy neutrino and MeV gamma-ray backgrounds have been veiled in mystery since their discoveries. We propose emission from stellar-mass BHs (sBHs) embedded in disks of active galactic nuclei as their possible sources. These sBHs are predicted to launch jets due to the Blandford–Znajek mechanism, which can produce intense electromagnetic, neutrino, and cosmic-ray emissions. We investigate whether these emissions can be the sources of cosmic high-energy particles. We find that emission from internal shocks in the jets can explain gamma rays from nearby radio-quiet Seyfert galaxies including NGC 1068, if the Lorentz factor of the jets (Γ j ) is high. On the other hand, for moderate Γ j , the emission can significantly contribute to the background gamma-ray and neutrino intensities in the ~MeV and ≲PeV bands, respectively. Furthermore, for moderate Γ j with efficient amplification of the magnetic field and cosmic-ray acceleration, the neutrino emission from NGC 1068 and the ultrahigh-energy cosmic rays can be explained. These results suggest that the neutrino flux from NGC 1068 as well as the background intensities of MeV gamma rays, neutrinos, and the ultrahigh-energy cosmic rays can be explained by a unified model. Future MeV gamma-ray satellites will test our scenario for neutrino emission.
... Similarly, the aforementioned lines observed for Mrk 231 (González-Alfonso et al. 2018) also suggest a ζ CR /n H ≃ (1−2)×10 −16 cm 3 s −1 for the outflowing component implying a ζ CR ∼ (0.5 − 2) × 10 −12 s −1 . Imanishi et al. (2018) studied OH + and H 2 O + lines of the extended halos of z ∼ 2.3 galaxies and derived a ζ CR ∼ (1 − 100) × 10 −16 s −1 , where the ionization rates in the compact starforming regions are expected to be orders of magnitude higher (Indriolo et al. 2018). Muller et al. (2016) also found higher than Milky Way CR ionization rate in the z = 0.89 molecular absorber toward PKS1830-211. ...
Understanding the nature of high-$z$ dusty galaxies requires a comprehensive view of their ISM and molecular complexity. However, the molecular ISM at high redshifts is commonly studied using only a few species beyond CO, limiting our understanding of the ISM in these objects. In this paper, we present the results of deep 3 mm spectral line surveys using the NOEMA targeting two lensed dusty galaxies: APM 08279+5255 (APM), a quasar at redshift $z=3.911$, and NCv1.143 (NC), a $z=3.565$ starburst galaxy. The spectral line surveys cover rest-frame frequencies from about 330-550 GHz. We report the detection of 38 and 25 emission lines in APM and NC, respectively. The spectra reveal the chemical richness and the complexity of the physical properties of the ISM. By comparing the spectra of the two sources and combining the gas excitation analysis, we find that the physical properties and the chemical imprints of the ISM are different between them: the molecular gas is more excited in APM, exhibiting higher molecular-gas temperatures and densities compared to NC; the chemical abundances in APM are akin to the values of local AGN, showing boosted relative abundances of the dense gas tracers that might be related to high-temperature chemistry and/or XDRs, while NC more closely resembles local starburst galaxies. The most significant differences are found in H2O, where the 448 GHz H2O line is significantly brighter in APM, likely linked to the intense far-infrared radiation from the dust powered by AGN. Our astrochemical model suggests that, at such high column densities, UV radiation is less important in regulating the ISM, while CRs (and/or X-rays and shocks) are the key players in shaping the abundance of the molecules. Such deep spectral line surveys open a new window to study the physical and chemical properties of the ISM and the radiation field of galaxies in the early Universe. (abridged)
... On the other hand, this also means that jets from ∼ 3 sBHs at ∼ 1 pc are directed to us, which may be problematic to be consistent with the X-ray flux from NGC1068. This is because the X-ray emission from corona in NGC1068 may be mostly absorbed at sub-parsec scales, instead of several parsec scales, by considering the amount of mass estimated in parsec scales (García-Burillo et al. 2016;Imanishi et al. 2018Imanishi et al. , 2020. In that case, the X-ray emission from jets at ∼ 1 pc may not be fully absorbed and significantly exceed the observed X-ray flux. ...
Some Seyfert galaxies are detected in high-energy gamma rays, but the mechanism and site of gamma-ray emission are unknown. Also, the origins of the cosmic high-energy neutrino and MeV gamma-ray backgrounds have been veiled in mystery since their discoveries. We propose emission from stellar-mass BHs (sBHs) embedded in disks of active galactic nuclei (AGN) as their possible sources. These sBHs are predicted to launch jets due to the Blandford-Znajek mechanism, which can produce intense electromagnetic, neutrino, and cosmic-ray emissions. We investigate whether these emissions can be the sources of cosmic high-energy particles. We find that emission from internal shocks in the jets can explain gamma rays from nearby radio-quiet Seyfert galaxies including NGC1068, if the Lorentz factor of the jets ($\Gamma_{\rm j}$) is high. On the other hand, for moderate $\Gamma_{\rm j}$, the emission can significantly contribute to the background gamma-ray and neutrino intensities in the $\sim {\rm MeV}$ and $\lesssim {\rm PeV}$ bands, respectively. Furthermore, for moderate $\Gamma_{\rm j}$ with efficient amplification of the magnetic field and cosmic-ray acceleration, the neutrino emission from NGC1068 and the ultrahigh-energy cosmic rays can be explained. These results suggest that the neutrino flux from NGC1068 as well as the background intensities of ${\rm MeV}$ gamma rays, neutrinos, and the ultrahigh-energy cosmic rays can be explained by a unified model. Future MeV gamma-ray satellites will test our scenario for neutrino emission.
... The many high spatial resolution molecular observations (e.g. García-Burillo et al. 2014;Imanishi et al. 2018;García-Burillo et al. 2016;Viti et al. 2014;Scourfield et al. 2020;Imanishi et al. 2020) of NGC 1068 reveal a complex structure and dynamics with: (i) a massive thick gas disk seen edge-on, obscuring the central engine, with a radius of ∼ 10 pc (García-Burillo et al. 2016;Imanishi et al. 2016Imanishi et al. , 2018; (ii) a counter-rotating inner disk (torus) at radii smaller than ∼ 1.2 pc (Impellizzeri et al. 2019); (iii) a molecular outflow in the inner region of the disk (≤ 3 pc) (Gallimore et al. 2016;García-Burillo et al. 2019;Impellizzeri et al. 2019). The torus is connected to the CND via a network of gas lanes whose kinematics are consistent with a 3D outflow geometry (García-Burillo et al. 2019); and (iv) a starburst ring (SB ring, r ∼ 1.3 kpc). ...
... The many high spatial resolution molecular observations (e.g. García-Burillo et al. 2014;Imanishi et al. 2018;García-Burillo et al. 2016;Viti et al. 2014;Scourfield et al. 2020;Imanishi et al. 2020) of NGC 1068 reveal a complex structure and dynamics with: (i) a massive thick gas disk seen edge-on, obscuring the central engine, with a radius of ∼ 10 pc (García-Burillo et al. 2016;Imanishi et al. 2016Imanishi et al. , 2018; (ii) a counter-rotating inner disk (torus) at radii smaller than ∼ 1.2 pc (Impellizzeri et al. 2019); (iii) a molecular outflow in the inner region of the disk (≤ 3 pc) (Gallimore et al. 2016;García-Burillo et al. 2019;Impellizzeri et al. 2019). The torus is connected to the CND via a network of gas lanes whose kinematics are consistent with a 3D outflow geometry (García-Burillo et al. 2019); and (iv) a starburst ring (SB ring, r ∼ 1.3 kpc). ...
We present hydrodynamic simulations of the interstellar medium (ISM) within the circumnuclear disk (CND) of a typical AGN-dominated galaxy influenced by mechanical feedback from an active galactic nucleus(AGN). The simulations are coupled with the CHIMES non-equilibrium chemistry network to treat the radiative-cooling and AGN-heating. A focus is placed on the central 100 pc scale where AGN outflows are coupled to the ISM and constrained by observational Seyfert-2 galaxies. AGN-feedback models are implemented with different wind-velocity and mass-loading factors. We post-process the simulation snapshots with a radiative-transfer code to obtain the molecular emission lines. We find that the inclusion of an AGN promotes the formation of CO in clumpy and dense regions surrounding supermassive-blackholes (SMBH). The CO(1-0) intensity maps ($<$6 Myr) in the CND seem to match well with observations of NGC 1068 with a best match for a model with 5000 $\rm km/s$ wind-velocity and a high mass-loading factor. We attempt to discern between competing explanations for the apparent counter-rotating gas disk in the NGC 1068 through an analysis of kinematic maps of the CO line emission. We suggest that mechanical AGN-feedback could explain the alignment-stability of position-angle across the different CND radii around the SMBH through momentum and energy loading of the wind. It is the wind-velocity that drives the disk out of alignment on a 100 pc scale for a long period of time. The position-velocity diagrams are in broad agreement with the predicted Keplerian rotation-curve in the model without-AGN, but the AGN models exhibit a larger degree of scatter, in better agreement with NGC 1068 observations.
... Recent sub-mm mapping observations of thermally-excited molecular emission lines in the galaxy using ALMA revealed that a parsec-scale torus structure, that surrounds the nuclear region, does not have the simple axisymmetric structure expected in the unified theory (e.g. Impellizzeri et al. 2019;Imanishi et al. 2018Imanishi et al. , 2020. Gallimore et al. (1996) reported the presence of H2O maser towards radio jet component C (hereafter the "off-nuclear maser"), which is located about 0.3 arcsecond (∼ 30 pc) north-east from the component S1. ...
... GHz, respectively. More details of the observations, calibrations, and data analysis are described in (Imanishi et al. 2018). We analyzed HCO + (J=4-3) emission line data at 356.734 GHz (Project: 2016.1.00232.S) obtained from the ALMA Science Archive. ...
... Sub-millimetre (266 GHz) continuum map of a nuclear region obtained by the ALMA(Imanishi et al. 2018). Contours are -2,3,5.1,9,15,46×1 ...
The results of high-resolution spectral-line observations of dense molecular gas are presented towards the nuclear region of the type 2 Seyfert galaxy NGC1068. MERLIN observations of the 22 GHz H$_2$O maser were made for imaging the known off-nuclear maser emission at radio jet component located about 0.3" north-east of the radio nucleus in the galaxy. High angular resolution ALMA observations have spatially resolved the molecular gas emissions of HCN and HCO$^{+}$ in this region. The off-nuclear maser spots are found to nearly overlap with a ring-like molecular gas structure and are tracing an evolving shock-like structure, which appears to be energized by interaction between the radio jet and circumnuclear medium. A dynamic jet-ISM interaction is further supported by a systematic shift of the centroid velocities of the off-nuclear maser features over a period of 35 years. The integrated flux ratios of the HCO$^{+}$ line emission features at component C suggest a kinetic temperature T$_{k}$ $\gtrsim$ 300K and an H$_2$ density of $\gtrsim$ 10$^6$ cm$^{-3}$, which are conditions where water masers may be formed. The diagnostics of the masering action in this jet-ISM interaction region is exemplary for galaxies hosting off-nuclear H$_2$O maser emission.
