We present observations using the Atacama Large Millimeter/submillimeter Array of the CO(2−1), HCN(3−2), and HCO+(3−2) lines in the nearby radio galaxy/brightest cluster galaxy (BCG) NGC 1275 with a ...spatial resolution of ∼20 pc. In previous observations, the CO(2−1) emission was detected as radial filaments lying in the east-west direction on a kiloparsec scale. We resolved the inner filament and found that it cannot be represented by a simple infalling stream on a sub-kiloparsec scale. The observed complex nature of the filament resembles the cold gas structure predicted by numerical simulations of cold chaotic accretion. Within the central 100 pc, we detected a rotational disk of molecular gas whose mass is ∼108 M . This is the first evidence of the presence of a massive cold gas disk on this spatial scale for BCGs. A crude estimate suggests that the accretion rate of the cold gas can be higher than that of hot gas. The disk rotation axis is approximately consistent with the radio-jet axis. This probably suggests that the cold gas disk is physically connected to the innermost accretion disk, which is responsible for jet launching. We also detected absorption features in the HCN(3−2) and HCO+(3−2) spectra against the radio continuum emission mostly radiated by a jet of size ∼1.2 pc. The absorption features are blueshifted from the systemic velocity by ∼300-600 km s−1, suggesting the presence of outflowing gas from the active galactic nucleus (AGN). We discuss the relation of the AGN feeding with cold accretion, the origin of blueshifted absorption, and an estimate of the black hole mass using molecular gas dynamics.
Abstract
We propose a new method of estimating the mass of a supermassive black hole residing in the centre of an active galaxy. The active galaxy M87 offers a convenient test case for the method due ...to the existence of a large amount of observational data on the jet and ambient environment properties in the central area of the object. We suggest that the observed transition of a jet boundary shape from a parabolic to a conical form is associated with the flow transiting from the magnetically dominated regime to the energy equipartition between plasma bulk motion and magnetic field. By coupling the unique set of observations available for the jet kinematics, environment and boundary profile with our MHD modelling under assumption on the presence of a dynamically important magnetic field in the M87 jet, we estimate the central black hole mass and spin. The method leads us to believe that the M87 supermassive black hole has a mass somewhat larger than typically accepted so far.
ABSTRACT We present full-polarization observations of the compact, steep-spectrum radio quasar 3C 286 made with the Atacama Large Millimeter and Submillimeter Array (ALMA) at 1.3 mm. These are the ...first full-polarization ALMA observations, which were obtained in the framework of Science Verification. A bright core and a south-west component are detected in the total intensity image, similar to previous centimeter images. Polarized emission is also detected toward both components. The fractional polarization of the core is about 17%; this is higher than the fractional polarization at centimeter wavelengths, suggesting that the magnetic field is even more ordered in the millimeter radio core than it is further downstream in the jet. The observed polarization position angle (or electric vector position angle (EVPA)) in the core is ∼39◦, which confirms the trend that the EVPA slowly increases from centimeter to millimeter wavelengths. With the aid of multi-frequency VLBI observations, we argue that this EVPA change is associated with the frequency-dependent core position. We also report a serendipitous detection of a sub-mJy source in the field of view, which is likely to be a submillimeter galaxy.
We present a study of the sub-parsec scale radio structure of the radio galaxy 3C 84/NGC 1275 based on the Very Long Baseline Array data at 43 GHz. We discover a limb brightening in the "restarted" ...jet that is associated with the 2005 radio outburst. In the 1990s, the jet structure was ridge brightening rather than limb brightening, despite the observations being done with similar angular resolutions. This indicates that the transverse jet structure has recently changed. This change in the morphology reveals an interesting agreement with the gamma -ray flux increase, i.e., the gamma -ray flux in the 1990s was at least seven times lower than the current one. One plausible explanation for the limb brightening is that the velocity structure of the jet is in the context of the stratified jet, which is a successful scenario that explains the gamma -ray emission in some active galactic nuclei. If this is the case, then the change in apparent transverse structure might be caused by the change in the transverse velocity structure. We argue that the transition from ridge brightening to limb brightening is related to the gamma -ray time variability on the timescale of decades. We also discuss the collimation profile of the jet.
ABSTRACT In the current paradigm, it is believed that the compact VLBI radio core of radio-loud active galactic nuclei (AGNs) represents the innermost upstream regions of relativistic outflows. These ...regions of AGN jets have generally been modeled by a conical outflow with a roughly constant opening angle and flow speed. Nonetheless, some works suggest that a parabolic geometry would be more appropriate to fit the high energy spectral distribution properties and it has been recently found that, at least in some nearby radio galaxies, the geometry of the innermost regions of the jet is parabolic. We compile here multi-frequency core sizes of archival data to investigate the typically unresolved upstream regions of the jet geometry of a sample of 56 radio-loud AGNs. Data combined from the sources considered here are not consistent with the classic picture of a conical jet starting in the vicinity of the super-massive black hole (SMBH), and may exclude a pure parabolic outflow solution, but rather suggest an intermediate solution with quasi-parabolic streams, which are frequently seen in numerical simulations. Inspection of the large opening angles near the SMBH and the range of the Lorentz factors derived from our results support our analyses. Our result suggests that the conical jet paradigm in AGNs needs to be re-examined by millimeter/sub-millimeter VLBI observations.
We present Very Long Baseline Array polarimetric observations of the innermost jet of 3C 84 (NGC 1275) at 43 GHz. A significant polarized emission is detected at the hotspot of the innermost ...restarted jet, which is located 1 pc south from the radio core. While the previous report presented a hotspot at the southern end of the western limb, the hotspot location has been moved to the southern end of the eastern limb. Faraday rotation is detected within an entire bandwidth of the 43 GHz band. The measured rotation measure (RM) is at most (6.3 1.9) × 105 rad m−2 and might be slightly time variable on the timescale of a month by a factor of a few. Our measured RM and the RM previously reported by the CARMA and SMA observations cannot be consistently explained by the spherical accretion flow with a power-law profile. We propose that a clumpy/inhomogeneous ambient medium is responsible for the observed RM. Using an equipartition magnetic field, we derive the electron density of 2 × 104 cm−3. Such an electron density is consistent with the cloud of the narrow line emission region around the central engine. We also discuss the magnetic field configuration from the black hole scale to the parsec scale and the origin of low polarization.
•A novel perspective on soil microbial stoichiometric homeostasis and flexibility.•We analysed a large soil microbial C:N:P stoichiometry dataset (4,363 pairs).•Homeostasis or flexibility of C:N and ...C:P showed clear geographical patterns.•These patterns are maintained by microbial responses to soil nutrient status.
The soil microbial biomass (SMB) adapts to altered soil resources either by maintaining roughly constant stoichiometry to soil carbon (C), nitrogen (N), and phosphorus (P) availability or by shifting to the elemental balance in the soil. Although a shift from stoichiometric homeostasis to flexibility (or vice versa) may affect terrestrial C and nutrient dynamics, a holistic understanding of the global distribution of microbial stoichiometric homeostasis and flexibility patterns is lacking. We synthesised three existing soil and SMB C:N:P stoichiometric ratio datasets with newly collected data to create a dataset containing 4,363 records. We devised a novel method for interpreting these data, in which the scatter plot representing the SMB C:P/soil C:P (y-axis) to SMB C:N/soil C:N (x-axis) relationship is classified into four distinct patterns: (1) both C:N and C:P are in homeostasis (along the 1:1 line), (2) only C:P exhibits flexibility (line parallel to the x-axis), (3) only C:N exhibits flexibility (line parallel to the y-axis), and (4) both C:N and C:P exhibit flexibility (concentrated at a single point). Applying this model to the large dataset, we found that microbial stoichiometric homeostasis and flexibility exhibit geographical patterns related to biome type, soil type, and precipitation, and more specifically, that natural ecosystems exhibit Pattern 1, whereas agroecosystems exhibit Pattern 3. Our findings also indicate that the SMB C:P/soil C:P and the SMB C:N/soil C:N relationships can be expressed as a simple function and are maintained by different microbial responses to soil nutrient status. These findings improve our understanding of the relationships between terrestrial C and nutrient dynamics and microbial stoichiometric homeostasis and flexibility and will enable improved modelling of these relationships.
ABSTRACT We investigate the distribution of Faraday rotation measure (RM) in the M87 jet at arcsecond scales by using archival polarimetric Very Large Array data at 8, 15, 22 and 43 GHz. We resolve ...the structure of the RM in several knots along the jet for the first time. We derive the power spectrum in the arcsecond-scale jet and find indications that the RM cannot be associated with a turbulent magnetic field with a 3D Kolmogorov spectrum. Our analysis indicates that the RM probed on jet scales has a significant contribution of a Faraday screen associated with the vicinity of the jet, in contrast with that on kiloparsec scales, typically assumed to be disconnected from the jet. Comparison with previous RM analyses suggests that the magnetic fields giving rise to the RMs observed in jet scales have different properties and are well less turbulent than those observed in the lobes.
Abstract
In this work, we interpret and discuss the time variable rotation measure (RM) found, for the first time over a 1-yr period, in the core region of a blazar. These results are based on a ...1-yr, multifrequency (15, 24 and 43 GHz) Very Long Baseline Array (VLBA) monitoring of the TeV blazar Markarian 421 (Mrk 421). We investigate the Faraday screen properties and its location with respect to the jet emitting region. Given that the 43-GHz radio core flux density and the RM time evolution suggest a similar trend, we explore the possible connection between the RM and the accretion rate. Among the various scenarios that we explore, the jet sheath is the most promising candidate for being the main source of Faraday rotation. During the 1-yr observing period, the RM trend shows two sign reversals, which may be qualitatively interpreted within the context of the magnetic tower models. We invoke the presence of two nested helical magnetic fields in the relativistic jet with opposite helicities, whose relative contribution produce the observed RM values. The inner helical field has the poloidal component (Bp) oriented in the observer’s direction and produces a positive RM, while the outer helical field, with Bp in the opposite direction, produces a negative RM. We assume that the external helical field dominates the contribution to the observed RM, while the internal helical field dominates when a jet perturbation arises during the second observing epoch. Being the intrinsic polarization angle parallel to the jet axis, a pitch angle of the helical magnetic field ϕ ≳ 70° is required. Additional scenarios are also considered to explain the observed RM sign reversals.
Summary
Background
Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous diseases. The phenotypes that have clinical features of both asthma and COPD are still incompletely ...understood.
Objective
To clarify the best discriminators of the asthma‐COPD overlap phenotype from asthma and COPD subgroups using a clustering approach.
Methods
This study assessed pathophysiological parameters, including mRNA expression levels of T helper cell‐related transcription factors, namely TBX21 (Th1), GATA3 (Th2), RORC (Th17) and FOXP3 (Treg), in peripheral blood mononuclear cells in asthma patients (n=152) and in COPD patients (n=50). Clusters were determined using k‐means clustering. Exacerbations of asthma and COPD were recorded during the 1‐year follow‐up period.
Results
The cluster analysis revealed four biological clusters: cluster 1, predominantly patients with COPD; cluster 2, patients with an asthma‐COPD overlap phenotype; cluster 3, patients with non‐atopic and late‐onset asthma; and cluster 4, patients with early‐onset atopic asthma. Hazard ratios for exacerbation were 2.5 (95% confidence interval CI, 1.1‐5.6) in cluster 1 and 2.3 (95% CI, 1.0‐5.0) in cluster 2 compared with patients in other clusters. Cluster 2 was discriminated from other clusters by total serum IgE level ≥310 IU/mL, blood eosinophil counts ≥280 cells/μL, a higher ratio of TBX21/GATA3, FEV1/FVC ratio <0.67 and smoking ≥10 pack‐years with an area under the curve of 0.94 (95% CI, 0.90‐0.98) in the receiver operating characteristic analysis.
Conclusions and Clinical Relevance
The asthma‐COPD overlap phenotype was characterized by peripheral blood eosinophilia and higher levels of IgE despite the Th2‐low endotype.
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