In this study, we investigate the line emissions from cold molecular gas based on our previous "radiation-driven fountain model," which reliably explains the spectral energy distribution of the ...nearest type 2 Seyfert galaxy, the Circinus galaxy. Using a snapshot of the best-fit radiation-hydrodynamic model for the central pc, in which non-equilibrium X-ray-dominated region chemistry is solved, we conduct post-processed non-local thermodynamic equilibrium radiation transfer simulations for the CO lines. We obtain a spectral line energy distribution with a peak around , and its distribution suggests that the lines are not thermalized. However, for a given line of sight, the optical depth distribution is highly non-uniform between and . The CO-to-H2 conversion factor ( ), which can be directly obtained from the results and is not a constant, depends strongly on the integrated intensity and differs from the fiducial value for local objects. exhibits a large dispersion of more than one order of magnitude, reflecting the non-uniform internal structure of a "torus." In addition, we found that the physical conditions differ between grid cells on a scale of a few parsecs along the observed lines of sight; therefore, a specific observed line ratio does not necessarily represent a single physical state of the interstellar medium.
We present the results of our ALMA observations of 11 (ultra)luminous infrared galaxies ((U)LIRGs) at J = 4-3 of HCN, HCO+, and HNC and J = 3-2 of HNC. This is an extension of our previously ...published HCN and HCO+ J = 3-2 observations to multiple rotational J-transitions of multiple molecules, to investigate how molecular emission line flux ratios vary at different J-transitions. We confirm that ultraluminous infrared galaxies (ULIRGs) that contain or may contain luminous obscured active galactic nuclei (AGNs) tend to show higher HCN-to-HCO+ flux ratios than starburst galaxies, both at J = 4-3 and J = 3-2. For selected HCN-flux-enhanced AGN-important ULIRGs, our isotopologue H13CN, H13CO+, and HN13C J = 3-2 line observations suggest a higher abundance of HCN than HCO+ and HNC, which is interpreted to be primarily responsible for the elevated HCN flux in AGN-important galaxies. For such sources, the intrinsic HCN-to-HCO+ flux ratios after line opacity correction will be higher than the observed ratios, making the separation between AGNs and starbursts even larger. The signature of the vibrationally excited (v2 = 1f) HCN J = 4-3 emission line is seen in one ULIRG, IRAS 12112−0305 NE. P Cygni profiles are detected in the HCO+ J = 4-3 and J = 3-2 lines toward IRAS 15250+3609, with an estimated molecular outflow rate of ∼250-750 M yr−1. The SiO J = 6-5 line also exhibits a P Cygni profile in IRAS 12112+0305 NE, suggesting the presence of shocked outflow activity. Shock tracers are detected in many sources, suggesting ubiquitous shock activity in the nearby ULIRG population.
We report on the relation between the mass of supermassive black holes (SMBHs; ) and that of hosting dark matter halos ( ) for 49 z ∼ 6 quasi-stellar objects (QSOs) with C ii158 m velocity-width ...measurements. Here, we estimate assuming that the rotation velocity from is equal to the circular velocity of the halo; we have tested this procedure using z ∼ 3 QSOs that also have clustering-based estimates. We find that a vast majority of the z ∼ 6 SMBHs are more massive than expected from the local - relation, with one-third of the sample by factors 102. The median mass ratio of the sample, , means that 0.4% of the baryons in halos are locked up in SMBHs. The mass growth rates of our SMBHs amount to ∼10% of the star formation rates (SFRs), or ∼1% of the mean baryon accretion rates, of the hosting galaxies. A large fraction of the hosting galaxies are consistent with average galaxies in terms of SFR and perhaps of stellar mass and size. Our study indicates that the growth of SMBHs ( ) in luminous z ∼ 6 QSOs greatly precedes that of hosting halos owing to efficient gas accretion even under normal star formation activities, although we cannot rule out the possibility that undetected SMBHs have local ratios. This preceding growth is in contrast to much milder evolution of the stellar-to-halo mass ratio.
UltraFast Outflows (UFOs), seen as X-ray blueshifted absorption lines in active galactic nuclei (AGNs), are considered to be a key mechanism for AGN feedback. In this scenario, UFO kinetic energy is ...transferred into the cold and extended molecular outflow observed at the millimeter/submillimeter wavelength, which blows away the gas and suppresses star formation and accretion onto the central black hole (BH). However, the energy transfer between the inner UFO and the outer molecular outflow has not yet been fully studied mainly due to the limited sample. In this paper, we perform a comparison of their kinetic energy using the millimeter/submillimeter published data and the X-ray archival data. Among 14 Seyfert galaxies whose molecular outflows are detected in the Institut de RAdioastronomie Millimétrique/Plateau de Bure Interferometer data, 8 targets are bright enough to perform spectral fitting in X-ray, and we have detected UFO absorption lines in 6 targets with a 90% significance level, using XMM-Newton and Suzaku satellites. The time-averaged UFO kinetic energy was derived from the spectral fitting. As a result, we have found that the energy-transfer rate (kinetic energy ratio of the molecular outflow to the UFO) ranges from ∼7 × 10−3 to ∼1, and has a negative correlation with the BH mass, which shows that the AGN feedback is more efficient in the lower mass BHs. This tendency is consistent with the theoretical prediction that the cooling timescale of the outflowing gas becomes longer than the flow timescale when the BH mass is smaller.
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-accreting supermassive black hole. We now report that we have detected the rotation of this compact emission, with the eastern and western sides being redshifted and blueshifted, respectively. Unlike the previously reported CO J = 6-5 emission, both the morphological and dynamical alignments of the HCN J = 3-2 and HCO+ J = 3-2 emission are roughly along the east-west direction (i.e., the expected torus direction), suggesting that these molecular lines are better probes of a rotating dense molecular gas component in the torus. The western part of the torus exhibits larger velocity dispersion and stronger emission in the HCN J = 3-2 and HCO+ J = 3-2 lines than the eastern part, revealing a highly inhomogeneous molecular torus. The dense molecular gas in the torus and that of the host galaxy at 0 5-2 0 from the AGN along the torus direction are found to be counter-rotating, suggesting an external process happened in the past at the NGC 1068 nucleus.
Abstract
We report on a study of X-ray-irradiated gas in the central ∼100 pc of the Circinus galaxy, which hosts a Compton-thick active galactic nucleus (AGN), at 10 pc resolution using Chandra and ...ALMA. Based on ∼200 ks Chandra/ACIS-S data, we created an image of the Fe Kα line at 6.4 keV, tracing X-ray-irradiated dense gas. The ALMA data in Bands 6 (∼270 GHz) and 7 (∼350 GHz) cover five molecular lines: CO(J = 3–2), HCN(J = 3–2), HCN(J = 4–3), HCO+(J = 3–2), and HCO+(J = 4–3). The detailed spatial distribution of dense molecular gas was revealed, and compared to the iron line image. The molecular gas emission appeared faint in regions with bright iron emission. Motivated by this, we quantitatively discuss the possibility that the molecular gas is efficiently dissociated by AGN X-ray irradiation (i.e., creating an X-ray-dominated region). Based on a non-local thermodynamic equilibrium model, we constrained the molecular gas densities and found that they are as low as interpreted by X-ray dissociation. Furthermore, judging from inactive star formation reported in the literature, we suggest that the X-ray emission has the potential to suppress star formation, particularly in the proximity of the AGN.
Abstract
We report the results of Atacama Large Millimeter/submillimeter Array (ALMA) 1–2 kpc resolution, three rotational transition-line (
J
= 2–1,
J
= 3–2, and
J
= 4–3) observations of multiple ...dense molecular gas tracers (HCN, HCO
+
, and HNC) for 10 nearby (ultra)luminous infrared galaxies ((U)LIRGs). Following the matching of beam sizes to 1–2 kpc for each (U)LIRG, the high-
J
-to-low-
J
transition-line flux ratios of each molecule and the emission-line flux ratios of different molecules at each
J
transition are derived. We conduct RADEX non-LTE model calculations and find that, under a wide range of gas density and kinetic temperature, the observed HCN-to-HCO
+
flux ratios in the overall (U)LIRGs are naturally reproduced with enhanced HCN abundance compared to HCO
+
. Thereafter, molecular gas properties are constrained primarily through the use of HCN and HCO
+
data and the adoption of fiducial values for the HCO
+
column density and HCN-to-HCO
+
abundance ratio. We quantitatively confirm the following: (i) molecular gas at the (U)LIRGs’ nuclei is dense (≳10
3–4
cm
−3
) and warm (≳100 K), (ii) the molecular gas density and temperature in nine ULIRGs’ nuclei are significantly higher than those of one LIRG’s nucleus, (iii) molecular gas in starburst-dominated sources tends to be less dense and cooler than ULIRGs with luminous AGN signatures. For six selected sources, we also apply a Bayesian approach by freeing all parameters and support the above main results. Our ALMA 1–2 kpc resolution, multiple transition-line data of multiple molecules are a very powerful tool for scrutinizing the properties of molecular gas concentrated around luminous energy sources in nearby (U)LIRGs’ nuclei.
Gravitational lensing sometimes dominates the observed properties of apparently very bright objects. We present morphological properties in the high-resolution (FWHM ∼ 0 15) Atacama Large ...Millimeter/submillimeter Array (ALMA) 1 mm map for an ultraluminous quasar at z = 6.30, SDSS J010013.02+280225.8 (hereafter J0100+2802), whose black hole (BH) mass MBH is the most massive (∼1.2 × 1010M ) at z > 6 ever known. We find that the continuum emission of J0100+2802 is resolved into a quadruple system within a radius of 0 2, which can be interpreted as either multiple dusty star-forming regions in the host galaxy or multiple images due to strong gravitational lensing. The Mg ii absorption and the potential Ly line features have been identified at z = 2.33 in the near-infrared spectroscopy toward J0100+2802, and a simple mass model fitting well reproduces the positions and flux densities of the quadruple system, both of which are consistent with the latter interpretation. Although a high-resolution map taken in the Advanced Camera for Survey on board Hubble Space Telescope (HST) shows a morphology with an apparently single component, in our fiducial lens mass model it can simply be explained by a ∼50 pc scale offset between the ALMA and HST emission regions. In this case, the magnification factor for the observed HST emission is obtained to ∼450, reducing the intrinsic MBH estimate to below 109 M . The confirmation or the rejection of the gravitational lensing scenario is important for our understanding of the supermassive BHs in the early universe.
ABSTRACT We present the results of our ALMA observations of three active galactic nucleus (AGN)-dominated nuclei in optical Seyfert 1 galaxies (NGC 7469, I Zw 1, and IC 4329 A) and eleven luminous ...infrared galaxies (LIRGs) with various levels of infrared estimated energetic contributions by AGNs at the HCN and HCO+ J = 3 − 2 emission lines. The HCN and HCO+ J = 3 − 2 emission lines are clearly detected at the main nuclei of all sources, except for IC 4329 A. The vibrationally excited (v2 = 1f) HCN J = 3 − 2 and HCO+ J = 3 − 2 emission lines are simultaneously covered, and HCN v2 = 1f J = 3 − 2 emission line signatures are seen in the main nuclei of two LIRGs, IRAS 12112+0305 and IRAS 22491-1808, neither of which shows clear buried AGN signatures in the infrared. If the vibrational excitation is dominated by infrared radiative pumping, through the absorption of infrared 14 m photons, primarily originating from AGN-heated hot dust emission, then these two LIRGs may contain infrared-elusive, but (sub)millimeter-detectable, extremely deeply buried AGNs. These vibrationally excited emission lines are not detected in the three AGN-dominated optical Seyfert 1 nuclei. However, the observed HCN v2 = 1f to v = 0 flux ratios in these optical Seyferts are still consistent with the intrinsic flux ratios in LIRGs with detectable HCN v2 = 1f emission lines. The observed HCN-to-HCO+ J = 3 − 2 flux ratios tend to be higher in galactic nuclei with luminous AGN signatures compared with starburst-dominated regions, as previously seen at J = 1 − 0 and J = 4 − 3.
Abstract Recent submillimeter observations have revealed signs of parsec-scale molecular inflow and atomic outflow in the nearest Seyfert 2 galaxy, the Circinus galaxy. To verify the gas kinematics ...suggested by these observations, we performed molecular and atomic line transfer calculations based on a physics-based 3D radiation-hydrodynamic model, which has been compared with multiwavelength observations in this paper series. The major-axis position–velocity diagram (PVD) of CO(3–2) reproduces the observed faint emission at the systemic velocity, and our calculations confirm that this component originates from failed winds falling back to the disk plane. The minor-axis PVD of C i ( 3 P 1 – 3 P 0 ), when created using only the gas with positive radial velocities, presents a sign of blueshifted and redshifted offset peaks similar to those in the observation, suggesting that the observed peaks indeed originate from the outflow, but that the model may lack outflows as strong as those in the Circinus galaxy. Similar to the observed HCN(3–2), the similar dense-gas tracer HCO + (3–2) can exhibit nuclear spectra with inverse P-Cygni profiles with ∼0.5 pc beams, but the line shape is azimuthally dependent. The corresponding continuum absorbers are inflowing clumps at 5–10 pc from the center. To detect significant absorption with a high probability, the inclination must be fairly edge-on (≳85°), and the beam size must be small (≲1 pc). These results suggest that HCN or HCO + and C i lines are effective for observing parsec-scale inflows and outflows, respectively.
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