Academic literature on the topic 'Radio lines:ISM'
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Journal articles on the topic "Radio lines:ISM"
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Morabito, Leah K., J. B. R. Oonk, Francisco Salgado, M. Carmen Toribio, Xander Tielens, and Huub Röttgering. "Discovery of Carbon Radio Recombination Lines in M82." Proceedings of the International Astronomical Union 10, S309 (July 2014): 141–44. http://dx.doi.org/10.1017/s174392131400948x.
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AbstractCold, diffuse HI clouds are a key component of the interstellar medium (ISM), and play an important role in the evolution of galaxies. Carbon radio recombination lines (CRRLs) trace this ISM stage, and with the enormous sensitivity of LOFAR we have already begun to map and constrain the physical properties of this gas in our own Galaxy. Using LOFAR's low band antenna, we have observed M 82 and present the first ever extragalactic detection of CRRLs. We stack 22 lines to find a 8.5-sigma detection. The line peak to continuum ratio is ∼0.003, with a FWHM of 31 km s−1. The CRRL feature is consistent with an origin in the cold, neutral medium in the direction of the nucleus of M 82.
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Bicknell, G. V., M. A. Dopita, and C. P. O'DEA. "Shock Excitation of Emission Lines and the Relation to GPS Sources." Symposium - International Astronomical Union 175 (1996): 469–70. http://dx.doi.org/10.1017/s0074180900081511.
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Gigahertz Peak Spectrum (GPS) and Compact Steep Spectrum (CSS) sources have attracted a large amount of attention in recent years since they occupy a surprisingly large fraction of the extragalactic radio source population. In this paper we summarise a theory which attempts to unify the optical emission line and radio properties of these sources. In outline the theory is as follows: The bow shock preceding the radio lobe driven into the ISM by a powerful radio jet ionizes the ISM producing both optical line emission and a free-free absorbing screen. The free-free absorption can explain the relationship between size and turnover frequency (Stanghellini et al., 1995) and the prediction of the line emission is in accord with the observation for a small sample of sources for which optical data are available.
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Docenko, Dmitrijs, and Rashid A. Sunyaev. "Hyperfine structure radio lines from hot ISM in elliptical galaxies." Proceedings of the International Astronomical Union 5, H15 (November 2009): 278. http://dx.doi.org/10.1017/s174392131000921x.
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AbstractHyperfine structure (HFS) line of 14N VII ion with rest frequency of ν = 53.04 GHz should be detectable from the interstellar medium in some of the densest and coolest cores of elliptical galaxies at redshifts exceeding 0.15 or so.
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Cordes, J. M. "Galactic structure and turbulence, pulsar distances, and the intergalactic medium." Proceedings of the International Astronomical Union 8, S291 (August 2012): 211–16. http://dx.doi.org/10.1017/s1743921312023691.
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AbstractThis paper summarizes how multi-wavelength measurements will be aggregated to determine Galactic structure in the interstellar medium (ISM) and produce the next-generation electron density model. Fluctuations in density and magnetic field from parsec scales down to about 1000 km cause a number of propagation effects in both radio waves and cosmic rays. Density microstructure appears to include Kolmogorov-like turbulence. The next generation electron-density model, NE2012, will include about double the number of lines of sight with dispersion and scattering measurements and it will be anchored with a much larger number of pulsar parallax distances. The foreground Galactic model is crucial for inferring similar ionized structures in the intergalactic medium (IGM) from scattering measurements on high-z objects. Intergalactic scattering is discussed with reference to distant sources of radio bursts. In particular, the cosmological radio scattering horizon is defined along with its analog for the ISM.
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Morganti, R., C. N. Tadhunter, T. A. Oosterloo, J. Holt, A. Tzioumis, and K. Wills. "The Impact of the Early Stages of Radio Source Evolution on the ISM of the Host Galaxies." Publications of the Astronomical Society of Australia 20, no. 1 (2003): 129–33. http://dx.doi.org/10.1071/as02056.
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AbstractThe study of both neutral and ionised gas in young radio sources is providing key information on the effect the radio plasma has on the ISM of these objects. We present results obtained for the compact radio sources PKS 1549–79, 4C 12.50 and PKS 1814–63 and for the intermediate-size radio galaxy 3C 459. At least in the first two, low ionisation optical emission lines and HI absorption appear to be associated with the extended, but relatively quiescent, dusty cocoon surrounding the nucleus. The [OIII] lines are, on the other hand, mostly associated with the region of interaction between the radio plasma and the ISM, indicating a fast outflow from the centre. A case of fast outflow (up to ∼1000 km s-1) is also observed in HI in the radio source 4C 12.50. As the radio source evolves, any obscuring material along the radio axis is swept aside until, eventually, cavities (of the same kind as observed e.g. in Cygnus A) are hollowed out on either side of the nucleus. We may witness this phase in the evolution of a radio source in the radio galaxy 3C 459.
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Chu, You-Hua. "Multi-wavelength View of the Interstellar Medium in the Large Magellanic Cloud." Publications of the Astronomical Society of Australia 15, no. 1 (1998): 136–40. http://dx.doi.org/10.1071/as98136.
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AbstractThe Large Magellanic Cloud (LMC) has been surveyed in optical emission lines, X-rays, radio continuum, HI, and CO lines. These surveys provide views of the interstellar medium (ISM) in the LMC of unprecedented clarity, allowing us to study astrophysical processes and to examine the relationship among the different phases of the ISM. Multi-wavelength images are used to illustrate the physical structures of supernova remnants, superbubbles, and supergiant shells, as well as the global interstellar structure of the LMC.
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Margulès, L., B. A. McGuire, C. J. Evans, R. A. Motiyenko, A. Remijan, J. C. Guillemin, A. Wong, and D. McNaughton. "Submillimeter-wave spectroscopy and the radio-astronomical investigation of propynethial (HC≡CCHS)." Astronomy & Astrophysics 642 (October 2020): A206. http://dx.doi.org/10.1051/0004-6361/202038230.
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Context. The majority of sulfur-containing molecules detected in the interstellar medium (ISM) are analogs of oxygen-containing compounds. Propynal was detected in the ISM in 1988, hence propynethial, its sulfur derivative, is a good target for an ISM search. Aims. Our aim is to measure the rotational spectrum of propynethial and use those measurements to search for this species in the ISM. To date, measurements of the rotational spectra of propynethial have been limited to a small number or transitions below 52 GHz. The extrapolation of the prediction to lines in the milimeter-wave domain is inaccurate and does not provide data to permit an unambiguous detection. Methods. The rotational spectrum was re-investigated up to 630 GHz. Using the new prediction lines of propynethial, as well as the related propynal, a variety of astronomical sources were searched, including star-forming regions and dark clouds. Conclusions. A total of 3288 transitions were newly assigned and fit together with those from previous studies, reaching quantum numbers up to J = 107 and Ka = 24. Watson’s symmetric top Hamiltonian in the Ir representation was used for the analysis, because the molecule is very close to the prolate limit. The search for propynethial resulted in a non-detection; upper limits to the column density were derived in each source.
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Emig, K. L., P. Salas, F. de Gasperin, J. B. R. Oonk, M. C. Toribio, H. J. A. Röttgering, and A. G. G. M. Tielens. "The first detection of radio recombination lines at cosmological distances." Astronomy & Astrophysics 622 (February 2019): A7. http://dx.doi.org/10.1051/0004-6361/201834052.
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Context. Recombination lines involving high principal quantum numbers (n ∼ 50 − 1000) populate the radio spectrum in large numbers. Low-frequency (< 1 GHz) observations of radio recombination lines (RRLs) primarily from carbon and hydrogen offer a new, if not unique, way to probe cold, largely atomic gas and warm, ionised gas in other galaxies. Furthermore, RRLs can be used to determine the physical state of the emitting regions, such as temperature and density. These properties make RRLs, potentially, a powerful tool of extragalactic interstellar medium (ISM) physics. At low radio frequencies, it is conceivable to detect RRLs out to cosmological distances when illuminated by a strong radio continuum. However, they are extremely faint (τpeak ∼ 10−3 − 10−4) and have so far eluded detection outside of the local universe. Aims. With observations of the radio quasar 3C 190 (z = 1.1946), we aim to demonstrate that the ISM can be explored out to great distances through low-frequency RRLs. Methods. 3C 190 was observed with the LOw Frequency ARray (LOFAR) and processed using newly developed techniques for spectral analysis. Results. We report the detection of RRLs in the frequency range 112 MHz–163 MHz in the spectrum of 3C 190. Stacking 13 α-transitions with principal quantum numbers n = 266 − 301, a peak 6σ feature of optical depth τpeak = (1.0 ± 0.2)×10−3 and FWHM = 31.2 ± 8.3 km s−1 was found at z = 1.124. This corresponds to a velocity offset of −9965 km s−1 with respect to the systemic redshift of 3C 190. Conclusions. We consider three interpretations of the origin of the RRL emission: an intervening dwarf-like galaxy, an active galactic nucleus (AGN) driven outflow, and the inter-galactic medium. We argue that the recombination lines most likely originate in a dwarf-like galaxy (M ∼ 109 M⊙) along the line of sight, although we cannot rule out an AGN-driven outflow. We do find the RRLs to be inconsistent with an inter-galactic medium origin. With this detection, we have opened up a new way to study the physical properties of cool, diffuse gas out to cosmological distances.
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Asvarov, A. I. "Radio Emission from Extended Shell-Like SNRs." Symposium - International Astronomical Union 188 (1998): 249–50. http://dx.doi.org/10.1017/s0074180900114974.
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Observations of the soft X-Ray background and interstellar UV absorption lines have indicated that a large fraction of interstellar space is filled with a high temperature low density “coronal” gas. In such low density environments SNRs will expand up to 200 pc in radius without thin shell formation which occurs due to radiative cooling effects. Such SNRs can occupy a large fraction of volume of Galaxy and can be the main source of background emissions. In the present work we examine the evolution of the radio emission of shell-like SNR evolving in the hot ISM.
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Balmaverde, Barbara, Alessandro Capetti, Alessandro Marconi, and Giacomo Venturi. "The VLT/MUSE view of the central galaxy in Abell 2052." Astronomy & Astrophysics 612 (April 2018): A19. http://dx.doi.org/10.1051/0004-6361/201732022.
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We report observations of the radio galaxy 3C 317 (at z = 0.0345) located at the center of the Abell cluster A2052, obtained with the VLT/MUSE integral field spectrograph. The Chandra images of this cluster show cavities in the X-ray emitting gas, which were produced by the expansion of the radio lobes inflated by the active galactic nucleus (AGN). Our exquisite MUSE data show with unprecedented detail the complex network of line emitting filaments enshrouding the northern X-ray cavity. We do not detect any emission lines from the southern cavity, with a luminosity asymmetry between the two regions higher than ~75. The emission lines produced by the warm phase of the interstellar medium (WIM) enable us to obtain unique information on the properties of the emitting gas. We find dense gas (up to 270 cm−3) that makes up part of a global quasi spherical outflow that is driven by the radio source, and obtain a direct estimate of the expansion velocity of the cavities (265 km s−1). The emission lines diagnostic rules out ionization from the AGN or from star-forming regions, suggesting instead ionization from slow shocks or from cosmic rays. The striking asymmetric line emission observed between the two cavities contrasts with the less pronounced differences between the north and south sides in the hot gas; this represents a significant new ingredient for our understanding of the process of the exchange of energy between the relativistic plasma and the external medium. We conclude that the expanding radio lobes displace the hot tenuous phase of the interstellar medium (ISM), but also impact the colder and denser ISM phases. These results show the effects of the AGN on its host and the importance of radio mode feedback.
Dissertations / Theses on the topic "Radio lines:ISM"
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Barnes, Peter J., Audra K. Hernandez, Stefan N. O’Dougherty, III William J. Schap, and Erik Muller. "THE GALACTIC CENSUS OF HIGH- AND MEDIUM-MASS PROTOSTARS. III. 12 CO MAPS AND PHYSICAL PROPERTIES OF DENSE CLUMP ENVELOPES AND THEIR EMBEDDING GMCs." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/622167.
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We report the second complete molecular line data release from the Census of High-and Medium-mass Protostars (CHaMP), a large-scale, unbiased, uniform mapping survey at sub-parsec resolution, of millimeter-wave line emission from 303 massive, dense molecular clumps in the Milky Way. This release is for all (CO)-C-12 J = 1 -> 0 emission associated with the dense gas, the first from Phase II of the survey, which includes (CO)-C-12, (CO)-C-13, and (CO)-O-18. The observed clump emission traced by both (CO)-C-12 and HCO+ (from Phase I) shows very similar morphology, indicating that, for dense molecular clouds and complexes of all sizes, parsec-scale clumps contain. similar to 75% of the mass, while only 25% of the mass lies in extended (>10 pc) or "low density" components in these same areas. The mass fraction of all gas above a density of 10(9) m(-3) is xi(9) greater than or similar to 50%. This suggests that parsec-scale clumps may be the basic building blocks of the molecular interstellar medium, rather than the standard GMC concept. Using (CO)-C-12 emission, we derive physical properties of these clumps in their entirety, and compare them to properties from HCO+, tracing their denser interiors. We compare the standard X-factor converting I (CO)-C-12 to N-H2 with alternative conversions, and show that only the latter give whole-clump properties that are physically consistent with those of their interiors. We infer that the clump population is systematically closer to virial equilibrium than when considering only their interiors, with perhaps half being long-lived (10s of Myr), pressure-confined entities that only terminally engage in vigorous massive star formation, supporting other evidence along these lines that was previously published.
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Seo, Youngmin, and Youngmin Seo. "The L1495-B218 Filaments in Taurus Seen in NH₃ & CCS and Dynamical Stability of Filaments and Dense Cores." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621572.
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We present deep NH₃ and CCS maps of L1495-B218 filaments and the dense cores embedded within the filaments in Taurus. The L1495-B218 filaments form an interconnected, nearby, large complex extending over 8 pc. We observed the filaments in NH₃ (1,1)&(2,2), CCS Nⱼ = 1₂-0₁, and HC₇N J = 21-20 with spectral resolution of 0.038 km/s and spatial resolution of 31". The CSAR algorithm, which is a hybrid of seeded-watershed and binary dendrogram algorithm, identifies 39 leaves and 16 branches in NH₃ (1,1). Applying a virial analysis for the 39 NH₃ leaves, we find only 9 out of 39 leaves are gravitationally bound, and 12 out of 30 gravitationally unbound leaves are pressure-confined. Our analysis suggests that a dense core may form as a pressure-confined structure, evolve to a gravitationally bound core, and then undergo collapse to form a protostar. We find that the L1495A, B213E, and B216 regions have strong CCS emission and the B211 and B218 regions have weak CCS emission. Analysis of CCS emission with NH₃ (1,1) and dust continuum emission shows that CCS is not a good tracer for starless core evolution. On the other hand, CCS appears to trace recently accreted gas in L1495A and L1521D. We also present more realistic dynamic stability conditions for dense cores and filaments. In a new analysis of stability conditions we account for converging motions which have been modeled toward starless cores and take the effect of radiation fields. We find that the critical size of a dense core having a homologous converging motion with its peak speed being the sound speed is roughly half of the critical size of the Bonnor-Ebert sphere. We also find the critical mass/line density of a dense core/filament irradiated by radiation to be considerably smaller than that of the Bonnor-Ebert sphere/isothermal cylinder when the radiation pressure is stronger than the central gas pressure of dense core/isothermal cylinder. For regions in the inner Galaxy and near OB associations, the critical mass/line density of a dense structure may be less than 20% of the critical mass/line density of Bonnor-Ebert sphere/isothermal cylinder.
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Rho, J., J. W. Hewitt, J. Bieging, W. T. Reach, M. Andersen, and R. Güsten. "DISCOVERY OF BROAD MOLECULAR LINES AND OF SHOCKED MOLECULAR HYDROGEN FROM THE SUPERNOVA REMNANT G357.7+0.3: HHSMT, APEX, SPITZER , AND SOFIA OBSERVATIONS." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/622645.
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We report a discovery of shocked gas from the supernova remnant (SNR) G357.7+0.3. Our millimeter and submillimeter observations reveal broad molecular lines of CO(2-1), CO(3-2), CO(4-3), (CO)-C-13 (2-1), and (CO)-C-13 (3-2), HCO+, and HCN using the Heinrich Hertz Submillimeter Telescope, the Arizona 12 m Telescope, APEX, and the MOPRA Telescope. The widths of the broad lines are 15-30 km s(-1), and the detection of such broad lines is unambiguous, dynamic evidence showing that the SNR G357.7+0.3 is interacting with molecular clouds. The broad lines appear in extended regions (>4'.5 x 5'). We also present the detection of shocked H-2 emission in the mid-infrared but lacking ionic lines using Spitzer/IRS observations to map a few-arcminute area. The H2 excitation diagram shows a best fit with a two-temperature local thermal equilibrium model with the temperatures of similar to 200 and 660 K. We observed [C II] at 158 mu m and high-J CO(11-10) with the German Receiver for Astronomy at Terahertz Frequencies (GREAT) on the Stratospheric Observatory for Infrared Astronomy. The GREAT spectrum of [C II], a 3 sigma detection, shows a broad line profile with a width of 15.7 km(-1) that is similar to those of broad CO molecular lines. The line width of [C II] implies that ionic lines can come from a low-velocity C-shock. Comparison of H2 emission with shock models shows that a combination of two C-shock models is favored over a combination of C- and J-shocks or a single shock. We estimate the CO density, column density, and temperature using a RADEX model. The best-fit model with n(H-2) = 1.7 x 10(4) cm(-3), N(CO) = 5.6 x 10(16) cm(-2), and T = 75 K can reproduce the observed millimeter CO brightnesses.
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Schmidt, D. R., and L. M. Ziurys. "NEW DETECTIONS OF HNC IN PLANETARY NEBULAE: EVOLUTION OF THE [HCN]/[HNC] RATIO." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/622874.
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New detections of HNC have been made toward 11 planetary nebulae (PNe), including K4-47, K3-58, K3-17, M3-28, and M4-14. These sources, which represent a wide range of ages and morphologies, had previously been observed in HCN by Schmidt & Ziurys. Measurements of the J = 1 -> 0 and J = 3 -> 2 transitions of HNC near 90 and 271 GHz were conducted using the new 12 m and the Sub-Millimeter Telescope of the Arizona Radio Observatory. HCN and HNC were also identified via their J = 1 -> 0 lines toward eight positions across the Helix Nebula (NGC 7293). Column densities for HNC, determined from radiative transfer modeling, were N-tot(HNC) similar to (0.06-4.0) x 10(13) cm(-2), corresponding to fractional abundances with respect to H-2 of f similar to (0.02-1.4) x 10(-7). The HCN and HNC column densities across the Helix were found to be N-tot (HCN) similar to (0.2-2.4). x. 10(12) cm(-2) and Ntot (HNC) similar to (0.07-1.6). x. 1012 cm(-2), with fractional abundances of (0.2-3.2) x 10(-7) and (0.09-2.2) x 10(-7). The [ HCN]/[ HNC] ratio varied between similar to 1-8 for all PNe, with [ HCN]/[ HNC] similar to 1-4 across the Helix. These values are greatly reduced from what has been found in asymptotic giant branch stars, where the ratio is typically > 100. Both the abundance of HNC and the [ HCN]/[ HNC] ratio do not appear to vary significantly with nebular age across a time span of similar to 10,000 years, in contrast to predictions of chemical models. The increase in HNC appears to arise in the proto-planetary stage, but becomes " frozen" once the PN phase is reached.
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Schmidt, D. R., and L. M. Ziurys. "New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C-60?" IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/626258.
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New detections of CCH have been made toward nine planetary nebulae (PNe), including K4-47, K3-58, K3-17, M3-28, and M4-14. Measurements of the N = 1 -> 0 and N = 3 -> 2 transitions of this radical near 87 and 262 GHz were carried out using the new 12 m and the Sub-Millimeter Telescope (SMT) of the Arizona Radio Observatory (ARO). The presence of fine and/or hyperfine structure in the spectra aided in the identification. CCH was not observed in two PNe which are sources of C-60. The planetary nebulae with positive detections represent a wide range of ages and morphologies, and all had previously been observed in HCN and HNC. Column densities for CCH in the PNe, determined from radiative transfer modeling, were N-tot(CCH) similar to 0.2-3.3 x 10(15) cm(-2), corresponding to fractional abundances with respect to H-2 of f similar to 0.2-47 x 10(-7). The abundance of CCH was found to not vary significantly with kinematic age across a time span of similar to 10,000 years, in contrast to predictions of chemical models. CCH appears to be a fairly common constituent of PNe that are carbon-rich, and its distribution may anti-correlate with that of C-60. These results suggest that CCH may be a product of C-60 photodestruction, which is known to create C-2 units. The molecule may subsequently survive the PN stage and populate diffuse clouds. The distinct, double-horned line profiles for CCH observed in K3-45 and M3-28 indicate the possible presence of a bipolar flow oriented at least partially toward the line of sight.
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Shaw, Gargi, G. J. Ferland, and I. Hubeny. "The Validity of 21 cm Spin Temperature as a Kinetic Temperature Indicator in Atomic and Molecular Gas." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625168.
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The gas kinetic temperature (T-K) of various interstellar environments is often inferred from observations that can deduce level populations of atoms, ions, or molecules using spectral line observations; H I 21 cm is perhaps the most widely used, and has a long history. Usually the H I 21 cm line is assumed to be in thermal equilibrium. and the populations are given by the Boltzmann distribution. A variety of processes, many involving Ly alpha, can affect the 21 cm line. Here we show how this is treated in the spectral simulation code Cloudy, and present numerical simulations of environments where this temperature indicator is used, with a detailed treatment of the physical processes that determine level populations within H-0. We discuss situations where this temperature indicator traces TK, cases where it fails, as well as the effects of Lya pumping on the 21 cm spin temperature. We also show that the Lya excitation temperature rarely traces the gas kinetic temperature.
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Roberts-Borsani, G. W., M. J. Jiménez-Donaire, M. Daprà, K. Alatalo, I. Aretxaga, J. Álvarez-Márquez, A. J. Baker, et al. "Multiwavelength Characterization of an ACT-selected, Lensed Dusty Star-forming Galaxy at z = 2.64." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625330.
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We present CI(2-1) and multi-transition (CO)-C-12 observations of a dusty star-forming galaxy, ACT J2029+0120, which we spectroscopically confirm to lie at z = 2.64. We detect CO(3-2), CO(5-4), CO(7-6), CO(8-7), and CI (2-1) at high significance, tentatively detect HCO+(4-3), and place strong upper limits on the integrated strength of dense gas tracers (HCN(4-3) and CS(7-6)). Multi-transition CO observations and dense gas tracers can provide valuable constraints on the molecular gas content and excitation conditions in high-redshift galaxies. We therefore use this unique data set to construct a CO spectral line energy distribution (SLED) of the source, which is most consistent with that of a ULIRG/Seyfert or QSO host object in the taxonomy of the Herschel Comprehensive ULIRG Emission Survey. We employ RADEX models to fit the peak of the CO SLED, inferring a temperature of T similar to 117 K and n(H2) similar to 10(5) cm(-3), most consistent with a ULIRG/QSO object and the presence of high-density tracers. We also find that the velocity width of the C I line is potentially larger than seen in all CO transitions for this object, and that the L'(Ci(2-1))/L'(CO(3-2)) ratio is also larger than seen in other lensed and unlensed submillimeter galaxies and QSO hosts; if confirmed, this anomaly could be an effect of differential lensing of a shocked molecular outflow.
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Li, Shanghuo, Junzhi Wang, Zhi-Yu Zhang, Min Fang, Juan Li, Jiangshui Zhang, Junhui Fan, Qingfeng Zhu, and Fei Li. "Millimetre spectral line mapping observations towards four massive star-forming H ii regions." OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/623847.
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We present spectral line mapping observations towards four massive star-forming regions Cepheus A, DR21S, S76E and G34.26+0.15 - with the IRAM 30-m telescope at the 2 and 3 mm bands. In total, 396 spectral lines from 51 molecules, one helium recombination line, 10 hydrogen recombination lines and 16 unidentified lines were detected in these four sources. An emission line of nitrosyl cyanide (ONCN, 14(0), 14-13(0), (13)) was detected in G34.26+0.15, as the first detection in massive star-forming regions. We found that c-C3H2 and NH2D show enhancement in shocked regions, as suggested by the evidence of SiO and/or SO emission. The column density and rotational temperature of CH3CN were estimated with the rotational diagram method for all four sources. Isotope abundance ratios of C-12/C-13 were derived using HC3N and its C-13 isotopologue, which were around 40 in all four massive star-forming regions and slightly lower than the local interstellar value (similar to 65). The N-14/N-15 and O-16/O-18 abundance ratios in these sources were also derived using the double isotopic method, which were slightly lower than in the local interstellar medium. Except for Cep A, the S-33/S-34 ratios in the other three targets were derived, which were similar to that in the local interstellar medium. The column density ratios of N(DCN)/N(HCN) and N( DCO+)/N(HCO+) in these sources were more than two orders of magnitude higher than the elemental [D]/[H] ratio, which is 1.5 x 10(-5). Our results show that the later stage sources, G34.26+0.15 in particular, present more molecular species than earlier stage sources. Evidence of shock activity is seen in all stages studied.
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Rice, Johnathan Scott. "The Transition From Diffuse to Dense Molecular Clouds." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1534945134382193.
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Niemeier, James J. "Radio in hydroscience: unconventional links and new sensor possibilities." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/863.
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One can use unlicensed and often very inexpensive radios for unconventional communication (underwater- and underground) links. However, one can go further, and use these radios as sensors rather than communication links. Such communication links and sensors can have important application in hydroscience. While the attenuation of RF signals is high in these mediums, by using the wireless sensor network (WSN) paradigm of multi-hop and retransmission, reliable networks can be formed underwater and underground. One no longer needs to think of RF modules as only a source of data transmission. This revelation lends itself to thinking of these modules as inexpensive RF wave generators at prescribed unlicensed frequencies. Analyzing the received signal strength indicator (RSSI) of a link over time, one can infer changes in the medium from the changes in RSSI. In this thesis, I develop a simple mathematical model to relate changes in RSSI to changes in the medium. Additionally, five experimentally validated examples demonstrate the possibility of non-traditional uses for RF modules. Demonstrated sensor possibilities include soil moisture estimation, leaf wetness measurement, and vegetation water content estimation. This thesis served to validate the use of inexpensive unlicensed RF modules as more than just communication links through air, but as links in unconventional media, and more importantly as measurement instruments.
Books on the topic "Radio lines:ISM"
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Shirokov, Igor', and Yuriy Gimpilevich. Research of communication channel characteristics. ru: INFRA-M Academic Publishing LLC., 2020. http://dx.doi.org/10.12737/1093426.
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The questions of studying the amplitude and phase characteristics of communication channels of radio engineering systems are considered. As part of the research, a homodyne method for converting microwave signals is proposed, which makes it possible to measure amplitude and phase fluctuations with high accuracy and with the utmost simplicity of measuring equipment. The development of the homodyne method of signal transformation for the purposes and tasks of determining the amplitude and phase fluctuations of signals during the propagation of radio waves on open lines of sight is presented. The features of homodyne signal transformation in the presence of various destabilizing factors are considered. The issues of synchronization of reference generators on different parts of the measuring route are considered. The results of theoretical and experimental studies of amplitude and phase fluctuations on land and sea lines of sight are presented.
For students and teachers, as well as anyone interested in radio engineering.
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Samama, Leo. The Meaning of Music. NL Amsterdam: Amsterdam University Press, 2016. http://dx.doi.org/10.5117/9789089649799.
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For virtually all of our lives, we are surrounded by music. From lullabies to radio to the praises sung in houses of worship, we encounter music at home and in the street, during work and in our leisure time, and not infrequently at birth and death. But what is music, and what does it mean to humans? How do we process it, and how do we create it? Musician Leo Samama discusses these and many other questions while shaping a vibrant picture of music's importance in human lives both past and present. What is remarkable is that music is recognised almost universally as a type of language that we can use to wordlessly communicate. We can hardly shut ourselves off from music, and considering its primal role in our lives, it comes as no surprise that few would ever want to. Able to transverse borders and appeal to the most disparate of individuals, music is both a tool and a gift, and as Samama shows, a unifying thread running throughout the cultural history of mankind.
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di Leonardo, Micaela. Black Radio/Black Resistance. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190870195.001.0001.
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Black Radio is a window into the most famous radio show you never heard of. The Tom Joyner Morning Show is a quarter-century-old syndicated black morning radio show reaching more than eight million adult, largely working-class listeners. It offers progressive political talk, soul music, humor, advice, philanthropy, and celebrity gossip. But the TJMS is not just an adult “old-school music” radio show: it is an on-air organizer, fusing progressive politics and aesthetics. It focuses on specific political issues affecting and enraging African Americans. Black Radio analyzes the TJMS’s rise in the Clinton era, and its coverage of key events—9/11, Hurricane Katrina, President Obama’s elections and terms, the murders of unarmed black Americans and the rise of Black Lives Matter, and the shocking 2016 Donald Trump electoral triumph. It showcases the varied, contentious, and blackly humorous voices of anchors, guests, and audience members. Finally, it investigates the new synergistic set of cross-medium ties and political connections now affecting print, broadcast, and online politics in anti-racist directions. Despite the dismal present, this new multiracial progressive public sphere has extraordinary potential for shaping future American politics. Black Radio, then, is more than the project of making the invisible visible, bringing to light a major counterpublic phenomenon unjustly ignored for reasons of color, class, generation, and medium. It tunes us in to an alternative understanding of the black public sphere in the digital age. Like the show itself, Black Radio is politically progressive, music-drenched, angry, and blisteringly funny.
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Publishng, Movie &. T. V. Guru. Don't Panic! I'm a Professional Radio Producer : Customized 100 Page Lined Notebook Journal Gift for a Busy Radio Producer: Far Better Than a Throw Away Greeting Card. Independently Published, 2020.
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Publishing, Radio Guru. Don't Panic! I'm a Professional Radio Engineer : Customized 100 Page Lined Notebook Journal Gift for a Busy Radio Engineer: Far Better Than a Throw Away Greeting Card. Independently Published, 2020.
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Publishing, Radio Guru. Don't Panic! I'm a Professional Radio Network Engineer : Customized 100 Page Lined Notebook Journal Gift for a Busy Radio Network Engineer: Far Better Than a Throw Away Greeting Card. Independently Published, 2020.
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Cohen, Laurie, and Joanne Duberley. Desert island data. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198796978.003.0002.
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Laurie Cohen and Joanne Duberley describe their use of an unconventional data source—a radio programme—to study celebrity careers. This source also includes music, which evokes memories, and elicits emotions not readily captured in conventional interviews. They used the archives of the BBC Radio 4 programme Desert Island Discs to study the careers of well-known research scientists. The programme’s format has been consistent over its 70-year history; ‘castaways’ from all walks of life are interviewed about their careers and are asked to select eight pieces of music, which reveal many other aspects of their lives. This research focused on the relationships between work and life course, the notion of career as performance, and the role of emotion in the narration of career. Desert Island Discs is part of an extensive archive. As time and funding for research are tight, rapid no-cost access to such data is valuable.
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Gereziher, Hayelom Yrgaw, and Naser Yenus Nuru. Structural estimates of the South African sacrifice ratio. 12th ed. UNU-WIDER, 2021. http://dx.doi.org/10.35188/unu-wider/2021/946-4.
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This paper estimates the output cost of fighting inflation—the sacrifice ratio—for the South African economy using quarterly data spanning the period 1998Q1–2019Q3. To compute the sacrifice ratio, the structural vector autoregressive model developed by Cecchetti and Rich (2001) based on Cecchetti (1994) is employed. Our findings show us a small sacrifice ratio, which lies within the range 0.00002–0.231 per cent with an average of 0.031 per cent, indicating a low level of output to be sacrificed while fighting inflation. Hence, the reserve bank is recommended to sustain an inflation rate within the target range and reap the benefits of a predictable and stable price path, as restrictive monetary policy has only a transitory effect on real variables like output.
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Landau, Iddo. Human Evil. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780190657666.003.0013.
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Some hold life to be meaningless because humanity is so evil. The chapter challenges several arguments that conclude that evil is highly pervasive, such as the argument from history; the argument from the significant failings of great people; the argument from psychological egoism, which claims that everything we do is ultimately based on the egoistic urge to increase the ratio of pleasant to unpleasant feelings we experience; and the argument from human malleability. The chapter suggests that there are many good people in the world. Moreover, even if most people were as evil as some arguments portray them, we could still lead meaningful lives.
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Lienhard, John H. The Engines of Our Ingenuity. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195135831.001.0001.
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Millions of people have listened to John H. Lienhard's radio program "The Engines of Our Ingenuity." In this fascinating book, Lienhard gathers his reflections on the nature of technology, culture, and human inventiveness. The book brims with insightful observations. Lienhard writes that the history of technology is a history of us--we are the machines we create. Thus farming dramatically changed the rhythms of human life and redirected history. War seldom fuels invention--radar, jets, and the digital computer all emerged before World War II began. And the medieval Church was a driving force behind the growth of Western technology--Cistercian monasteries were virtual factories, whose water wheels cut wood, forged iron, and crushed olives. Lienhard illustrates his themes through inventors, mathematicians, and engineers--with stories of the canoe, the DC-3, the Hoover Dam, the diode, and the sewing machine. We gain new insight as to who we are, through the familiar machines and technologies that are central to our lives.
Book chapters on the topic "Radio lines:ISM"
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Loeb, Abraham, and Steven R. Furlanetto. "The 21-cm Line." In The First Galaxies in the Universe. Princeton University Press, 2013. http://dx.doi.org/10.23943/princeton/9780691144917.003.0012.
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This chapter describes how the 21-cm line is used to study the high-z Universe. It introduces the spin-flip or the hyperfine line—a transition driven by the interaction of the spins of the proton and electron, whose relative directions affect the energy of the electron's orbit. An atom in the upper state eventually undergoes a spin-flip transition, emitting a photon with a wavelength of 21 cm. As the chapter shows, this transition is extremely weak, so the effective intergalactic medium (IGM) optical depth is only of the order of 1 percent: this makes the entire neutral IGM accessible during the cosmic dawn. Moreover, the transition energy is so low that it provides a sensitive thermometer of the low-temperature IGM, and as a low-frequency radio transition, it can be seen across the entirety of the IGM against the cosmic microwave background.
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Benthall, Jonathan. "Mona Siddiqui." In Islamic Charities and Islamic Humanism in Troubled Times. Manchester University Press, 2016. http://dx.doi.org/10.7228/manchester/9781784993085.003.0015.
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This review of Mona Siddiqui’s Christians, Muslims, and Jesus (Yale University Press) was published in the Times Literary Supplement on 29 January 2014, under the heading “Abraham’s children”. As well as being a senior academic in religious studies, Siddiqui is well known to the British public as a frequent contributor to the “Thought for the Day” religious slot in the early morning “Today” programme broadcast by the BBC’s Radio Four. SIddiqui makes an important contribution to comparative theological debate by comparing and contrasting the roles of Jesus (Isa) and Mary (Maryam) in the New Testament and the Qur’an, and more broadly in the two religious traditions as they evolved. She also reflects on the specifically Christian semiotics of the Cross. The Chapter ventures some further reflections on how the two traditions may be compared along broader lines.
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Erhan, Deniz Umut, and M. Ugur Akdogan. "General Outlook on Financial Structure and Capital Adequacy of ISE-30 Companies during Economic Crisis (2008-2009)." In Technology and Financial Crisis, 163–79. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-3006-2.ch015.
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In the simplest terms, economic crises could be recognised as abnormal fluctuations adversely impacting market conditions. Despite subsequent economic recoveries, markets and the financial system remain in a period of significant uncertainty after such crises. The baseline scenario is for balance sheets to strengthen gradually as the economy recovers and as progress is made in addressing structural problems in financial positions. However, substantial downside risks always remain for companies. Even companies with a high “Capital Adequacy Ratio” (CAR) face the difficult challenge of managing a smooth transition to self-sustaining growth while stabilising debt burdens under low and uncertain economic prospects. Without further bolstering of balances sheets, markets remain susceptible to funding shocks that could intensify deleveraging pressures and place further drag on public finances and recovery. Companies have proven resilient to economic turbulence but are vulnerable to a slowdown and face risks in managing sizable and potentially volatile capital inflows. Policy actions need to be intensified to contain risks, address debt burdens, and implement effective and institutional frameworks to ensure financial stability. Based on this perspective and through applying the financial soundness indicators methodology, the financial structures and soundness indicators of the top 30 companies on the Istanbul Stock Exchange (ISE-30) are subjected to an assessment for determining the impact of the global crisis. The short- and long-run credits and non-monetary debit lines of ISE-30 companies are investigated together with the momentum of growth in assets, liabilities, and cash-flow stabilities. The financial soundness of ISE-30 companies is discussed in terms of the “capital-liabilities ratios” performance measure. Finally, the study focuses on long-run economic impacts and the analysis assumes that companies should transition to new levels of capital and liquidity to strengthen their financial stability and sustainability.
Conference papers on the topic "Radio lines:ISM"
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Rantala, A. "Practical interference problems in ISM-band microwave links." In IEE Two Day Conference. Getting the Most Out of the Radio Spectrum. IEE, 2002. http://dx.doi.org/10.1049/ic:20020244.
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Docenko, Dmitrijis, and Rashid Sunyaev. "The $^{14}$N VII 5.6-mm line for studies of WHIM, QSO and hot ISM." In From Planets to Dark Energy: the Modern Radio Universe. Trieste, Italy: Sissa Medialab, 2008. http://dx.doi.org/10.22323/1.052.0090.
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Bakhsh, Zohre Mashayekh, Javad Zeraatkar Moghaddam, and Mehrdad Ardebilipour. "Optimal Cooperative Relaying for Cognitive Radio Networks with Three Unlicensed Links." In 2018 9th International Symposium on Telecommunications (IST). IEEE, 2018. http://dx.doi.org/10.1109/istel.2018.8660994.
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Punzi, Kristina, G. Sacco, Thierry Forveille, Pierre Hily-Blant, and Joel Kastner. "THE FIRST UNBIASED RADIO EMISSION LINE SURVEY OF THE PROTOPLANETARY DISK ORBITING LKCA 15." In 69th International Symposium on Molecular Spectroscopy. Urbana, Illinois: University of Illinois at Urbana-Champaign, 2014. http://dx.doi.org/10.15278/isms.2014.rf02.
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Jean-Yves Rosaye. "Study of S/N Ratio by simulation of experiment in a semiconductor manufacturing line." In 2007 International Symposium on Semiconductor Manufacturing. IEEE, 2007. http://dx.doi.org/10.1109/issm.2007.4446850.
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Dabiri, Mohammad Taghi, Mohammad Javad Saber, and Seyed Mohammad Sajad Sadough. "BER performance of OFDM-based wireless services over radio-on-FSO links in the presence of turbulence and pointing errors." In 2016 8th International Symposium on Telecommunications (IST). IEEE, 2016. http://dx.doi.org/10.1109/istel.2016.7881776.
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Tuv, Alexander L., and Yury I. Gudkov. "Adaptive Measuring System for On-line Monitoring of Parameters of Radio-electronic Means." In 2019 International Conference "Quality Management, Transport and Information Security, Information Technologies" (IT&QM&IS). IEEE, 2019. http://dx.doi.org/10.1109/itqmis.2019.8928451.
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Baker, Evan, Noah Shaw, Chen Wang, Hao Zhang, and Cheng Sun. "Passive Split Ring Resonator for Continuous Physiological Sensing Through Conductivity Measurements." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-66744.
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The Split Ring Resonator (SRR) has been developed and explored for a number of sensing technologies and devices. A SRR can be equivalently regarded as an LC circuit; changes in the dielectric environment will change the equivalent capacitance of the resonator, resulting in a shift of the resonant frequency as well as the quality factor (Q-factor).This makes the device a promising application for continuous personal health monitoring throughout the day. In this work, we are developing a passive radio frequency sensor based on ring resonator designs. The targeted frequency band is within 2.4–2.5GHz ISM (Industrial-Scientific-Medical radio band) and is available for medical devices. The resonator structure is first simulated using Finite Difference Time Domain (FDTD) method by CST Microwave Studio to determine the resonant frequency. Then for the experimental study, a microstrip transmission line with a double split ring resonator (DSRR) was fabricated on a printed circuit board (PCB) with biocompatible PVC coating on top. Tuning the thickness and material of the biocompatible coating can further improve the biocompatibility, Q-factor, and resulting sensitivity (mS) of the device. Reflection spectrum (S11) is measured using a network analyzer at 100 mW. The current design senses changes in conductivity down to 0.5 mS. By reducing coating thickness, reducing the spacing between resonators, and with more efficient resonator designs we expect to further improve this sensitivity. This sensor could be utilized by either implanted into the interstitial layer beneath the skin or embedded into a contact lens to sense tear salinity levels.
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Li, Zhong, Rajeev K. Jaiman, Mun Yew Daniel Tham, and Boo Cheong Khoo. "Two-Dimensional Numerical Simulations of Wall Proximity Effect on Cylinders." In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41639.
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In the oil and offshore industry, it is a common phenomenon that subsea pipelines placed on or in the proximity of the seabed are exposed to underwater waves and currents. Free spanning in sections along the length of pipeline frequently results from the erosion of sediments or the irregular terrain. This scenario can be modelled by a much more simplified set-up, where a circular cylinder situated near a plane wall is subjected to the oncoming flows. In this case, unlike the well-studied isolated cylinder, the hydrodynamic forces exerting on the near-wall cylinder will depend largely upon on the gap between the wall and the cylinder itself. In this work, flows around a stationary and a freely vibrating two-dimensional circular cylinder near a plane boundary are numerically simulated using the Immersed Interface Method (IIM) and Finite Element Method (FEM) with Arbitrary Lagrangian-Eulerian (ALE) approach, respectively. In the case of a stationary cylinder, instead of a fixed wall, a moving wall with no-slip boundary is considered in order to avoid the complex involvement of the boundary layer and to focus only on the shear-free wall proximity effects in evaluating the lift and drag forces in the low Reynolds number regime (Re ≤ 200), with the aim of validating our IIM solver since it is the first time to apply IIM in solving flows past a near-wall cylinder. The gap ratio e/D is typically taken from 0.1 to 2.0 in this part of studies, where e denotes the gap between the cylinder and the wall and D denotes the diameter of the cylinder. The key findings are that the mean drag coefficient increases and peaks at e/D = 0.5 with the increase of e/D and keeps decreasing from e/D = 0.5 to e/D = 2.0, while the mean lift coefficient decreases monotonically with the increase of e/D. In the case of the freely vibrating cylinder in both transverse and in-line directions, the fixed wall is used to include the shear-layer effect from the bottom wall in considering the near-wall vortex-induced vibration (VIV) by using FEM with ALE approach. It can be concluded from our observations that when the cylinder is brought closer to the wall from e/D = 10.0 to e/D = 0.75, the peak transverse displacement amplitude decreases, while the peak in-line displacement amplitude increases, by greater than 20 times that of an isolated cylinder.
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Gopan, Gayatri, Geetha Narayanan, Sreejith G. Nair, Prakash Purushothaman, Rona Joseph, Rekha A. Nair, and Jagathnath Krishna. "Outcome of Treatment in Elderly Myeloma—A Single-Centre Experience." In Annual Conference of Indian Society of Medical and Paediatric Oncology (ISMPO). Thieme Medical and Scientific Publishers Pvt. Ltd., 2021. http://dx.doi.org/10.1055/s-0041-1735368.
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Abstract Introduction Multiple myeloma (MM) accounts for approximately 1% of all cancers and 10% of all hematologic malignancies. In our institution, we see around 200 patients with myeloma every year. We present our experience with multiple myeloma in the patients aged more than 60 years. Objectives This is a retrospective study of 300 newly diagnosed multiple myeloma patients above 60 years of age treated in the Department of Medical Oncology, Regional Cancer Center, Thiruvananthapuram, Kerala, India, during the period between 2014 and 2017. The medical records of the patients were studied and following data were collected: demographic and clinical details, diagnostic and staging workup, primary treatment, response assessment, relapse, and survival. Survival was estimated using the Kaplan–Meier method. Results A total of 300 patients were included in the study. The median age was 66 years with a male-to-female ratio of 1.4:1. The common clinical presentations were backache (134), fatigue (49), lower respiratory infection (20), and paraparesis (14). Monoclonal protein was immunoglobulin (Ig)-G in 199 patients (66.6%), IgA in 52 patients (17.4%), IgM in 2 patients, and IgD in 1 patient. Light-chain disease was seen in 42 patients (14%). One hundred and sixty patients (53.5%) had ISS stage III. Only 285 patients received treatment, of which 203 (67.8%) received bortezomib-based regimen, - bortezomib and dexamethasone (BD; 33.4%); bortezomib, lenalidomide, and dexamethasone (BLD; 19.7%); bortezomib, cyclophosphamide, and dexamethasone (VCD; 8.7%); bortezomib, thalidomide, and dexamethasone (BTD; 2.3%); and bortezomib, melphalan, and prednisolone (3.7%). Nonbortezomib-based regimens used were melphalan and prednisolone (MP) alone or with thalidomide or lenalidomide (15%), lenalidomide and dexamethasone (LD; 10.4%), and thalidomide and dexamethasone (TD; 2%). Response assessment was done as per IMWG guidelines. Fifty-seven (26.3%) patients achieved complete response (CR), 94 (43.3%) achieved very good partial response (VGPR), 19 (8.8%) attained partial response (PR), 15 (5.6%) had stable disease, and 46 (15.4%) developed progressive disease. With bortezomib-based regimens, 119 patients (58.3%) achieved CR/VGPR, and with non-bortezomib based regimens, 42 patients (51.2%) achieved CR/VGPR. One hundred and forty-three patients (47.8%) received maintenance therapy of which 79 received maintenance with bortezomib, 49 with lenalidomide, and 15 with thalidomide. The average duration of maintenance was 24 months. Second-line chemotherapy regimens were used in 37 patients. Agents used were MP, LD, TD, and VCD. With second-line treatment, 15 patients achieved VGPR, 10 patients achieved partial response, and 25 patients developed progressive disease. Third-line chemotherapy regimens were used in 22 patients and the regimens used were pomalidomide and dexamethasone, MP, TD, LD, vincristine, doxorubicin, and dexamethasone and carfilzomib and dexamethasone. At a median follow-up of 34 months, the 2-year overall survival (OS) was 68%. The median progression-free survival was 21 months. The 2-year OS for patients receiving initial bortezomib-based regimen was 67.8% and non-bortezomib based regimen was 68% which was similar. Conclusion In this study, CR/VGPR rates and 2-year OS in patients treated with bortezomib and non-bortezomib based regimens were not statistically significant.
Reports on the topic "Radio lines:ISM"
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van den Boogaard, Vanessa, Wilson Prichard, Rachel Beach, and Fariya Mohiuddin. Strengthening Tax-Accountability Links: Fiscal Transparency and Taxpayer Engagement in Ghana and Sierra Leone. Institute of Development Studies, November 2020. http://dx.doi.org/10.19088/ictd.2020.002.
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There is increasingly strong evidence that taxation can contribute to expanded government responsiveness and accountability. However, such positive connections are not guaranteed. Rather, they are shaped by the political and economic context and specific policies adopted by governments and civil society actors. Without an environment that enables tax bargaining, there is a risk that taxation will amount to little more than forceful extraction. We consider how such enabling environments may be fostered through two mixed methods case studies of tax transparency and taxpayer engagement in Sierra Leone and Ghana. We highlight two key sets of findings. First, tax transparency is only meaningful if it is accessible and easily understood by taxpayers and relates to their everyday experiences and priorities. In particular, we find that taxpayers do not just want basic information about tax obligations or aggregate revenue collected, but information about how much revenue should have been collected and how revenues were spent. At the same time, taxpayers do not want information to be shared with them through a one-way form of communication, but rather want to have spaces for dialogue and interaction with tax and government officials, including through public meetings and radio call-in programmes. Second, strategies to encourage taxpayer engagement are more likely to be effective where forums for engagement are perceived by taxpayers to be safe, secure, and sincere means through which to engage with government officials. This has been most successful where governments have visibly demonstrated responsiveness to citizen concerns, even on a small scale, while partnering with civil society to foster trust, dialogue and expanded knowledge. These findings have significant implications for how governments design taxpayer education and engagement programmes and how civil society actors and development partners can support more equitable and accountable tax systems. Our findings provide concrete lessons for how governments can ensure that information shared with taxpayers is meaningful and accessible. Moreover, we show that civil society actors can play important roles as translators of tax information, enablers of public forums and dialogues around tax issues, and trainers of taxpayers, supporting greater tax literacy and sustained citizen engagement.