High-speed Outflow Research Articles

The black hole masses of high-redshift QSOs

ABSTRACT Observations of high-redshift quasars frequently promote suggestions of large black hole masses, whose presence so early in cosmic time is not easily explicable. I consider the parallel with ultraluminous X-ray sources (ULXs) – now known to be stellar-mass black hole (and neutron star) binaries apparently radiating far above their Eddington luminosities LEdd. The true luminosity in ULXs is actually only of order LEdd, for stellar-mass accretors, but has a very anisotropic (‘beamed’) component, plus a near-isotropic component of similar luminosity but much lower specific intensity. Observers viewing ULXs from within the beam but assuming spherical symmetry deduce a luminosity ≫LEdd. These features appear because the accretors are fed mass at highly super-Eddington rates, most of it expelled in high-speed (v > 0.2c) outflows from the accretion disc. I show that in similarly beamed AGN, emission-line properties would be essentially the same as in unbeamed sources, but standard virial mass indicators unusable because velocity widths are dominated by the outflows, not bound motions about the black holes. In an ensemble of this kind the apparently most luminous systems are always the most distant, but have the lowest black hole masses. Interpreting observations of this ensemble without knowing that they are beamed leads instead to very high black hole mass estimates. The analogy with ULXs therefore suggests that high-redshift quasars might actually have central black hole masses which could have grown from stellar values within the lookback time. I consider how one might test these ideas observationally.

The AGN Feedback in Compact Galaxies: On the Impact of a More Massive Central Black Hole

We conduct high-resolution hydrodynamical simulations using the MACER framework to investigate the interplay between the interstellar medium, active galactic nuclei (AGN) feedback and black hole (BH) feeding in a massive compact galaxy, with an emphasis on the impact of different central BH masses. We find that with a more massive central BH, high-speed outflows are more prominent, and the gas fraction in the compact galaxy is reduced. Due to the lower gas density and higher gas temperature, the compact galaxy with a more massive BH (MAS galaxy) remains predominantly single-phase with the cooling time t cool ≳ 100t ff. In contrast, the compact galaxy with the reference BH mass (REF galaxy) maintains a higher gas fraction with a shorter cooling time, slightly more multiphase gas and less prominent outflows. We further demonstrate that the difference in gas thermal states and kinematics is caused by the stronger AGN feedback in the compact galaxy with a more massive BH, where the AGN wind power is twice as much as that with the reference BH. Since the AGN feedback efficiently suppresses the inflow rate and the BH feeding rate, the BH mass growth is significant in neither the compact galaxy with the reference BH nor that with the more massive BH, only by 24% and 11% of the initial BH mass, respectively, over the entire evolution time of 10 Gyr. We thus posit that without ex situ mass supply from mergers, the massive BHs in compact galaxies cannot grow significantly via gas accretion during the late phase, but might have already formed by the end of the rapid early phase of galaxy formation.

The Evolution of Collisionless Magnetic Reconnection from Electron Scales to Ion Scales

Abstract It is generally accepted that collisionless magnetic reconnection is initiated on electron scales, which is mediated by electron kinetics. In this paper, by performing a two-dimensional particle-in-cell simulation, we investigate the transition of collisionless magnetic reconnection from electron scales to ion scales in a Harris current sheet with and without a guide field. The results show that after magnetic reconnection is triggered on electron scales, the electrons are first accelerated by the reconnection electric field around the X line, and then leave away along the outflow direction. In the Harris current sheet without a guide field, the electron outflow is symmetric and directed away from the X line along the center of the current sheet, while the existence of a guide field will distort the symmetry of the electron outflow. In both cases, the high-speed electron outflow is decelerated due to the existence of the magnetic field B z , then leading to the pileup of B z . With the increase of B z , the ions are accelerated by the Lorentz force in the outflow direction, and an ion outflow at about one Alfvén speed is at last formed. In this way, collisionless magnetic reconnection is transferred from the electron scales to the ion scales.

Numerical simulation of the process of gas outflow into an open pipe with an obstacle filled with a liquid (water, lead)

Submerged gas jets find a wide variety of industrial applications, and their behavior is characterized by the ratio of inertia to buoyancy and can vary from the emergence of individual bubbles to stable jets. A numerical study of the high-speed outflow of gas under a pressure of 18 MPa into a cavity with an obstacle filled with a liquid under a pressure of 2 MPa is carried out. The simulation is performed using the VOF method in conjunction with the k-ε turbulence model. The calculations are realized for three distances between the outflow hole and the obstacle: 100, 200, and 300 mm. Principal scenarios of gas jet evolution and characteristic expiration times are obtained.

Two-dimensional Particle-in-cell Simulation of Magnetic Reconnection in the Downstream of a Quasi-perpendicular Shock

Abstract In this paper, by performing a two-dimensional particle-in-cell simulation, we investigate magnetic reconnection in the downstream of a quasi-perpendicular shock. The shock is nonstationary, and experiences cyclic reformation. At the beginning of the reformation process, the shock front is relatively flat, and part of the upstream ions are reflected by the shock front. The reflected ions move upward in the action of the Lorentz force, which leads to the upward bending of the magnetic field lines at the foot of the shock front, and then a current sheet is formed due to the squeezing of the bending magnetic field lines. The formed current sheet is brought toward the shock front by the solar wind, and the shock front becomes irregular after interacting with the current sheet. Both the current sheet carried by the solar wind and the current sheet associated with the shock front are then fragmented into many small filamentary current sheets. Electron-scale magnetic reconnection may occur in several of these filamentary current sheets when they are convected into the downstream, and magnetic islands are generated. A strong reconnection electric field and energy dissipation are also generated around the X line, and a high-speed electron outflow is also formed.

Morphologic differences in radial grooves on martian layered (fluidized) ejecta: Implications for emplacement processes and conditions

Detailed morphologic and morphometric analysis of the radial grooves on Martian layered ejecta indicates that the grooves fall into three groups that correlate with different types of layered ejecta craters. We collected over 16,000 width and length measurements of 2402 radial grooves on the inner ejecta layers of 36 relatively fresh, layered ejecta craters. These include seven single layered ejecta craters (SLE), seven double layered Type-2 (DLE Type-2), ten double ejecta layer Type-1 (DLE-Type-1), and twelve multiple ejecta layer (MLE) test craters. These test craters are in the diameter range 8.3 km – 38.8 km for latitudes ranging from 45oS to 54oN. Radial grooves resembling longitudinal grooves in landslides throughout the solar system occur on all ejecta layers of SLE, DLE Type-2, and MLE craters (i.e., SDM grooves). This leads us to propose that SDM grooves are structures formed in flowing ejecta by the same processes that produce longitudinal grooves in landslides (e.g., shear and divergent flow). In contrast, the radial grooves on the inner and outer ejecta layers of DLE Type-1 are morphologically and morphometrically different from one another and from SDM grooves. The only type of geophysical flows that form grooves similar to grooves on the inner ejecta layers of DLE Type-1 craters are ones produced by high velocity (i.e., supersonic) blast surges associated with explosive volcanic eruptions (e.g., that occurred during the May 18th1980 eruption of Mount St. Helens USA). This leads us to propose that these Martian grooves are produced by high-speed outflow of particles and gas towards the last phase of crater formation. Furthermore, we propose that this high speed flow is generated when volatile-rich target materials slide into the crater cavity to mix with hot impactite. This generates a fuel-coolant explosion that creates a blast surge that subsequently produces the grooves on the inner ejecta layer. In addition, as the velocity of the outflow drops to subsonic outward of the inner ejecta layer, both erosion and deposition processes operate that result in deposition of a thin layer of material that contains channel-like grooves that are unique to this ejecta layer of this type of crater. This thin deposit is found on the outer ejecta layers, and beyond (on the terrain surrounding fresh DLE Type-1 craters). The production of these grooves on DLE Type-1 ejecta layers likely destroys and/or masks SDM grooves that may have initially formed on DLE Type-1 ejecta layers when they were initially emplaced as dense ground hugging flows.

Observations of a plectonemic configuration in a stable magnetized plasma jet

Astrophysical jets are collimated high-speed outflows emerging from spinning and accreting matter around celestial objects and may spontaneously result from self-organized processes. Magnetic self-organization is commonly observed in laboratory plasma physics experiments; however, they require close-fitting flux conservers to constrain and stabilize the toroidal or cylindrical structures. Here we report the first observations of a long, stable, free-boundary plasma jet far from chamber walls, embedding a double-helix magnetic structure resembling a force-free plectonemic Taylor state. The jets arise from an experimental setup that mimics an accretion disk and has no close-fitting solid flux conserver. The results support the hypothesis that self-organization could be a universal, intrinsic explanation for jet formation, collimation, and stability and may help explain double-helix features in celestial observations.

Design and verification of a hermetic high-speed turbogenerator concept for biomass and waste heat recovery applications

Many waste heat recovery and biomass applications offer opportunities for small-scale steam turbines to produce electricity and to improve systems’ energy efficiency. However, the currently used axial turbine-based technology is generally characterized by a relatively large physical size and poor design and off-design performances. To overcome these challenges, a new compact water-cooled high-speed radial outflow turbine concept is proposed. While the previous understanding of the chosen novel rotor water cooling approach indicates general system feasibility, improved turbine performance, and good potential, the scientific literature lacks relevant information. Since the design of high-speed machines is always case-dependent, every concept must be verified. Hence, to provide verification and new scientific information, this study combines analytical, numerical, and experimental analyses. The results predict turbine performance levels comparable with the previous radial outflow design, and its efficiency was found to exceed those of conventional turbines. During the experiments, the turbine also produced electricity from poor-quality steam, and its rotor dynamic behavior and magnetic bearing performance were close to the predicted results. These findings are considered a verification of the proposed concept. Furthermore, the rotor water cooling approach improved the stability of the system operation and although its physical behavior was not fully resolved, the study was able to verify its feasibility. In addition, at below 200 €/kW, the turbogenerator costs are competitive against competing technologies.

Nature and Origins of Rich Complexes of C iv Associated Absorption Lines

Abstract Rich complexes of associated absorption lines (AALs) in quasar spectra provide unique information about gaseous infall, outflows, and feedback processes in quasar environments. We study five quasars at redshifts z ~ 3.1–4.4 with AAL complexes containing from 7 to 18 C iv λ1548, 1551 systems in high-resolution spectra. These complexes span velocity ranges ≲3600 km s−1 within ≲8200 km s−1 of the quasar redshifts. All are highly ionized with no measurable low-ionization ions like Si ii or C ii, and all appear to form in the quasar/host galaxy environments based on evidence for line locking, partial covering of the background light source, strong N v absorption, and/or roughly solar metallicities, and on the implausibility of such complexes forming in unrelated intervening galaxies. Most of the lines in all five complexes identify high-speed quasar-driven outflows at velocity shifts v ≲ − 1000 km s−1. Four of the complexes also have lines at smaller blueshifted velocities that might form in ambient interstellar clouds, low-speed outflows, or at feedback interfaces in the host galaxies where high-speed winds impact and shred interstellar clouds. The partial covering we measure in some of the high-speed outflow lines require small absorbing clouds with characteristic sizes ≲1 pc or ≲0.01 pc. The short survival times of these clouds require locations very close to the quasars, or cloud creation in situ at larger distances perhaps via feedback/cloud-shredding processes. The AAL complex in one quasar, J1008+3623, includes unusually narrow C iv systems at redshifted velocities 350 ≲ v ≲ 640 km s−1 that are excellent candidates for gaseous infall toward the quasar, e.g., “cold-mode” accretion or a gravitationally bound galactic fountain.

Helical Shear-Flow Stabilization of an Astrophysically Relevant Laboratory Plasma Jet.

Astrophysical jets are collimated, high-speed outflows observed to be natural features of celestial objects that spin and accrete matter. From protoplanetary nebula and young stellar objects to active galactic nuclei, common features suggest that universal mechanisms may lead to the remarkable straightness observed in many jets. Here we report observations from a new astrophysically relevant laboratory plasma jet experiment demonstrating the formation of long-lived, collimated, high aspect-ratio jets. The magnetized jets have strong helical shear flows and remain stable to instabilities over many growth times. These observations corroborate theoretical predictions that strong helical shear flows can stabilize current-driven instabilities in magnetically confined plasmas, solar prominences, and magnetically driven astrophysical jets in nature.

A Giant Lyα Nebula and a Small-scale Clumpy Outflow in the System of the Exotic Quasar J0952+0114 Unveiled by MUSE∗

Abstract The well-known quasar SDSS J095253.83+011421.9 (J0952+0114) at z = 3.02 has one of the most peculiar spectra discovered so far, showing the presence of narrow Lyα and broad metal emission lines. Although recent studies have suggested that a proximate damped Lyα absorption (PDLA) system causes this peculiar spectrum, the origin of the gas associated with the PDLA is unknown. Here we report the results of observations with the Multi Unit Spectroscopic Explorer (MUSE) that reveal a new giant (≈100 physical kpc) Lyα nebula. The detailed analysis of the Lyα velocity, velocity dispersion, and surface brightness profiles suggests that the J0952+0114 Lyα nebula shares similar properties with other QSO nebulae previously detected with MUSE, implying that the PDLA in J0952+0144 is covering only a small fraction of the solid angle of the QSO emission. We also detected bright and spectrally narrow C iv λ1550 and He ii λ1640 extended emission around J0952+0114 with velocity centroids similar to the peak of the extended and central narrow Lyα emission. The presence of a peculiarly bright, unresolved, and relatively broad He ii λ1640 emission in the central region at exactly the same PDLA redshift hints at the possibility that the PDLA originates in a clumpy outflow with a bulk velocity of about 500 km s−1. The smaller velocity dispersion of the large-scale Lyα emission suggests that the high-speed outflow is confined to the central region. Lastly, the derived spatially resolved He ii/Lyα and C iv/Lyα maps show a positive gradient with the distance to the QSO, hinting at a non-homogeneous distribution of the ionization parameter.

The Dynamical Behavior of Reconnection-driven Termination Shocks in Solar Flares: Magnetohydrodynamic Simulations

Abstract In eruptive solar flares, termination shocks (TSs), formed when high-speed reconnection outflows collide with closed dense flaring loops, are believed to be one of the possible candidates for plasma heating and particle acceleration. In this work, we perform resistive magnetohydrodynamic simulations in a classic Kopp–Pneuman flare configuration to study the formation and evolution of TSs, and we analyze in detail the dynamic features of TSs and variations of the shock strength in space and time. This research focuses on the fast-reconnection phase when plasmoids form and produce small-scale structures inside the flare current sheet. It is found that the TS emerges once the downward outflow colliding with closed magnetic loops becomes supermagnetosonic and immediately becomes highly dynamical. The morphology of a TS can be flat, oblique, or curved depending on the detailed interactions between the outflows/plasmoids and the highly dynamic plasma in the loop-top region. The TS becomes weaker when a plasmoid is crossing through, or may even be destroyed by well-developed plasmoids and then reconstructed above the plasmoids. We also perform detailed statistical analysis on important physical quantities along and across the shock front. The density and temperature ratios range from 1 to 3 across the TS front, and the pressure ratio typically has larger values up to 10. We show that weak guide fields do not strongly affect the Mach number and compression ratios, and the TS length becomes slightly larger in the case with thermal conduction.

Binary Interactions, High-Speed Outflows and Dusty Disks during the AGB-To-PN Transition

It is widely believed that the dramatic transformation of the spherical outflows of AGB stars into the extreme aspherical geometries seen during the planetary nebula (PN) phase is linked to binarity and driven by the associated production of fast jets and central disks/torii. The key to understanding the engines that produce these jets and the jet-shaping mechanisms lies in the study of objects in transition between the AGB and PN phases. I discuss the results of our recent studies with high-angular-resolution (with ALMA and HST) and at high-energies (with GALEX, XMM-Newton and Chandra) of several such objects, which reveal new details of close binary interactions and high-speed outflows. These include two PPNe (the Boomerang Nebula and IRAS 16342-3814), and the late carbon star, V Hya. The Boomerang Nebula is notable for a massive, high-speed outflow that has cooled below the microwave background temperature, making it the coldest object in the Universe. IRAS 16342-3814 is the prime example of the class of water-fountain pre-planetary nebulae or PPNe (very young PPNe with high-velocity H2O masers) and shows the signature of a precessing jet. V Hya ejects high-speed bullets every 8.5 years associated with the periastron passage of a companion in an eccentric orbit. I discuss our work on AGB stars with strongly-variable high-energy (FUV, X-ray) emission, suggesting that these objects are in the early stages of binary interactions that result in the formation of accretion disks and jets.

The Coldest Place in the Universe: Probing the Ultra-cold Outflow and Dusty Disk in the Boomerang Nebula

Abstract Our Cycle 0 ALMA observations confirmed that the Boomerang Nebula is the coldest known object in the universe, with a massive high-speed outflow that has cooled significantly below the cosmic background temperature. Our new CO 1–0 data reveal heretofore unseen distant regions of this ultra-cold outflow, out to ≳120,000 au. We find that in the ultra-cold outflow, the mass-loss rate ( ) increases with radius, similar to its expansion velocity (V)—taking , we find . The mass in the ultra-cold outflow is M ⊙, and the Boomerang’s main-sequence progenitor mass is M ⊙. Our high angular resolution ( ) CO J = 3–2 map shows the inner bipolar nebula’s precise, highly collimated shape, and a dense central waist of size (FWHM) ∼1740 au × 275 au. The molecular gas and the dust as seen in scattered light via optical Hubble Space Telescope imaging show a detailed correspondence. The waist shows a compact core in thermal dust emission at 0.87–3.3 mm, which harbors M ⊙ of very large (∼millimeter-to-centimeter sized), cold ( K) grains. The central waist (assuming its outer regions to be expanding) and fast bipolar outflow have expansion ages of and : the “jet-lag” (i.e., torus age minus the fast-outflow age) in the Boomerang supports models in which the primary star interacts directly with a binary companion. We argue that this interaction resulted in a common-envelope configuration, while the Boomerang’s primary was an RGB or early-AGB star, with the companion finally merging into the primary’s core, and ejecting the primary’s envelope that now forms the ultra-cold outflow.

Nodal Analysis for Unconventional Reservoirs—Principles and Application

Summary Nodal analysis is the standard technique used to evaluate the performance of integrated production systems. Two curves represent the capacities of the inflow and of the outflow, and the intersection of the two curves gives the solution operating point. Limitations of traditional nodal analysis include: Results are offered only at a snapshot, not as a function of time. Inflow-performance-relationship (IPR) models are limited, with none available for shale gas wells. Analysis is performed on a well-by-well basis, with no account of multiwell interference. We propose a new nodal-analysis method that enables the study of transient production systems, such as unconventional reservoirs, with IPR models generated from a high-speed semianalytical reservoir simulator and outflow curves generated from a steady-state pipeline simulator. The use of analytical reservoir simulation allows accurate, reliable modeling of the real inflow system. The new approach studies the time-lapse behavior of the system, with consideration of production history and neighboring-well interference. This new method enables the study of transient deliverability at the wellhead, where the measurement is usually available, and shows the time-lapse relationship between wellhead pressure and production rate. We provide examples of wellhead deliverability and choke management and explain advantages of the method with case studies involving tight and shale wells. The method is also applied to design and optimize artificial lift in unconventional wells and to study the method's validity over time. In addition, we discuss an example of operational well dynamics with time-lapse nodal analysis. Furthermore, this new method generates discussion about some concepts that are often taken for granted—What should be the definition of IPR in a transient production system? On the IPR curve, is the zero-rate-pressure the reservoir pressure? Can IPR curves at two different timesteps cross each other? Finding the answers to these questions will help us better understand production systems. The commonly used productivity-index (PI) method is reviewed and compared with the new method. Results show that one should not use the PI method when well operational conditions change.

ALMA OBSERVATIONS OF THE COLDEST PLACE IN THE UNIVERSE: THE BOOMERANG NEBULA

The Boomerang Nebula is the coldest known object in the Universe, and an extreme member of the class of Pre-Planetary Nebulae, objects which represent a short-lived transitional phase between the AGB and Planetary Nebula evolutionary stages. Previous single-dish CO (J=1-0) observations (with a 45 arcsec beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang with ALMA in the CO J=2-1 and J=1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with HST and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible is likely due to preferential illumination of the cold high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist -- these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (mm-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultracold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.

The twin amplatz sheath method: a modified technique of percutaneous cystolithotripsy for large bladder stones in female patients.

To minimize the operative time and to avoid open cystolithotomy in women with large bladder stone (>5 cm), we present here a modification of percutaneous cystolithotomy, a well-described standard procedure for urinary bladder stones. With this technique, suprapubic percutaneous access was achieved under cystoscopic guidance. The suprapubic tract was dilated and an Amplatz sheath of 30 Fr was placed. Simultaneously, the urethra was sequentially dilated with fascial dilators and a 28 Fr Amplatz sheath was guided into the bladder and the foot end of the table lowered to 20° to facilitate high-speed outflow of irrigant and stone particles. A 26.5 Fr nephroscope was passed through the suprapubic Amplatz sheath and the stone was fragmented by intracorporeal pneumatic device keeping the stone close to the proximal end of the urethral Amplatz. These maneuvers help in washing out stone fragments periurethrally and keeping the endoscopic vision clear while breaking the stone.

SIMULTANEOUS OBSERVATION OF SOLAR OSCILLATIONS ASSOCIATED WITH CORONAL LOOPS FROM THE PHOTOSPHERE TO THE CORONA

The solar oscillations along one coronal loop in AR 11504 are observed simultaneously in white light emission and Doppler velocity by SDO/HMI, and in UV and EUV emissions by SDO/AIA. The technique of the time-distance diagram is used to detect the propagating oscillations of the emission intensities along the loop. We find that although all the oscillation signals were intercorrelated, the low chromospheric oscillation correlated more closely to the oscillations of the transition region and corona than to those of the photosphere. Situated above the sunspot, the oscillation periods were similar to 3 minutes in the UV/EUV emissions; however, moving away from the sunspot and into the quiet Sun, the periods became longer, e. g., up to similar to 5 minutes or more. In addition, along another loop we observe both the high-speed outflows and oscillations, which roughly had a one-to-one corresponding relationship. This indicates that the solar periodic oscillations may modulate the magnetic reconnections between the loops of the high and low altitudes that drive the high-speed outflows along the loop.

High-speed outflow keeps black holes in check

High-speed outflow keeps black holes in check

The radio core and jet in the broad absorption-line quasar PG 1700+518

Abstract The blueshifted broad absorption lines (BAL) or troughs are observed in active galactic nuclei (AGNs) when our line of sight is intercepted by a high-speed outflow (wind), likely originating in the accretion disc. The outflow or wind can shed light on the internal structure obscured by the AGN torus. Recently, it has been shown that this outflow is rotating in the BAL quasar PG 1700+518, further supporting the accretion disc origin of the wind. With the purpose of giving independent constraints on the wind geometry, we performed high-resolution European very long baseline interferometry (VLBI) Network (EVN) observations at 1.6 GHz in 2010. Combining the results with the Very Large Array (VLA) archival data at 8.4 GHz, we present its jet structure on scales of parsec (pc) to kiloparsec (kpc) for the first time. The source shows two distinct jet features in east–west direction with a separation of around 4 kpc. The eastern feature, which has so far been assumed to hide the core, is a kpc-scale hotspot, which is completely resolved out in the EVN image. In the western jet feature, we find a compact jet component, which pinpoints the position of the central black hole in the galaxy. Jet components on both sides of the core are additionally detected in the north-west–south-east direction, and they show a symmetric morphology on scale of <1 kpc. This two-sided jet feature is not common in the known BAL quasars and indicates that the jet axis is far away from the line of sight. Furthermore, it is nearly parallel to the scattering plane revealed earlier by optical polarimetry. By analogy to polar-scattered Seyfert 1 galaxies, we conclude that the jet likely has a viewing angle around 45°. The analogy is further supported by the recent report of significant cold absorption in the soft X-rays, a nearly unique feature to polar-scattered Seyfert galaxies. Finally, our observations have confirmed the earlier finding that the majority of radio emission in this galaxy arises from AGN activity rather than star formation.