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Academic literature on the topic 'HII regions'

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Journal articles on the topic "HII regions"

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Chu, You Hua, and Robert C. Kennicutt. "Internal motions of HII regions and giant HII regions." Astrophysics and Space Science 216, no. 1-2 (June 1994): 253–62. http://dx.doi.org/10.1007/bf00982502.

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Kurtz, Stan. "Hypercompact HII regions." Proceedings of the International Astronomical Union 1, S227 (May 2005): 111–19. http://dx.doi.org/10.1017/s1743921305004424.

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Shapiro, Paul R., Ira Wasserman, and Mark L. Giroux. "Cosmological HII Regions." Symposium - International Astronomical Union 117 (1987): 366. http://dx.doi.org/10.1017/s0074180900150533.

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We have generalized the classical description of ionization front propagation to the case of a point source in a uniform, cosmologically expanding gas. We present illustrative curves for the comoving radius and peculiar velocity for several turn-on redshifts, z0N, for Ωtot = 1, Ωb = 0.1, h = 1. The quantity RS is the generalized Strömgren radius [RS = RSi (1 + z0N)/(1 + z), RSi = (3Nu/4πnH,i2 α2)1/3, Nu = photoionizing number flux per source, α2 = recombination rate to n = 2, nH,i = nHo (1 + z0N)3]. The quantity T0N = 2 (1 + z0N)−3/2/(3H0). We also plot ζ, the value of (2nQoNph, Q/3HonHo) needed to ionize the IGM with overlapping QSO HII regions by redshift z0V for QSO turn-on at various z0N, where Nph, Q = ionizing photon luminosity per QSO, nQo = QSO number density (present co-moving value), nH = H density of IGM, and nH/nHo = nQ/nQo = (1 + z)3. From a recent preprint by Koo (1985), we estimate ζ ≲ 1 (for Ωb = 0.1, h = 1) for QSO's with L ∼ 1045 erg s−1. In this case, the observed QSO's cannot be the sole source of the IGM ionization that is implied by the null detection of the Gunn-Peterson effect for QSO's with z > 2.
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Hughes, V. A. "Variable HII Regions." International Astronomical Union Colloquium 120 (1989): 104–10. http://dx.doi.org/10.1017/s0252921100023526.

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Initial CO observations of the Cepheus OB cloud by Sargent (1977), identified the condensation known as Cepheus A. Other observations have shown that it has the normal empirical indications of a star forming region. In the radio continuum, using the WSRT, it consists of two thermal components (Hughes and Wou-terloot 1982). The West component is associated with the Herbig-Haro object GGD-37, and will not be considered further here. The East component when observed further with the VLA, is seen to consist of two strings of about 14 compact HII regions, and is the subject of the present paper.
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O'dell, C. R. "Turbulence in HII Regions." Publications of the Astronomical Society of the Pacific 98 (November 1986): 1106. http://dx.doi.org/10.1086/131943.

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Fuentes-Masip, O., H. O. Castañeda, and C. Muñoz-Tuñón. "New Methods to Measure HII Regions Diameters." International Astronomical Union Colloquium 149 (1995): 143–47. http://dx.doi.org/10.1017/s025292110002282x.

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AbstractObservations of the giant irregular galaxy NGC 4449 are being used to study the correlations between the diameter or luminosity and the velocity dispersion of its giant HII regions (GHRs), understanding as GHRs those HII regions with supersonic velocity dispersions. In the central part of this galaxy the HII regions overlap, and also there is a strong, morphologically diffuse emission that permeates the main body of NGC 4449, both effects making difficult the detection, identification and separation of HII regions. We have developed new techniques to solve these problems, obtaining HII regions parameters equivalent to the ones that would be got if the HII regions did not overlap and if the diffuse emission did not exist.
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Chu, You-Hua, and Robert C. Kennicutt. "Supernova Remnants in Giant HII Regions." International Astronomical Union Colloquium 101 (1988): 201–4. http://dx.doi.org/10.1017/s0252921100102374.

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Giant HII regions contain large numbers of massive stars, and hence are expected to contain large numbers of SNRs. Until recently, however, only a few SNRs have been identified in extragalactic giant HII regions. Moreover, most of these SNRs are located at the outskirts of HII regions, instead of the core where most of the stars are located. The low detection rate and the outlying locations of the SNRs may be due to: 1) observational difficulties - the background HII regions are much more luminous than the SNRs in both optical line emission and radio continuum; 2) intrinsic invisibility of SNRs - stellar wind and SNRs may have created a supershell (Mac Low and McCray 1987), and the core of a giant HII region is filled with hot tenuous coronal gas; or 3) a genuine deficiency of supernovae and SNRs in the HII regions (Sramek and Weedman 1986).
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Kaufman, Michele, R. C. Kennicutt, and F. N. Bash. "Giant H II Regions in M81." Symposium - International Astronomical Union 116 (1986): 503–4. http://dx.doi.org/10.1017/s0074180900149459.

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Giant HII regions are important tracers of recent star formation in distant galaxies. For a selection of HII regions in our galaxy where the exciting stars can be identified, Rumstay (1985) finds that the measured Hα and radio continuum luminosities of an HII region correlate with the stellar ionizing flux derived from model atmospheres and the known exciting stars. Therefore, we use flux measurements of giant HII regions as an index of the distribution of O stars in M81.
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Stéphan, G., P. Schilke, J. Le Bourlot, A. Schmiedeke, R. Choudhury, B. Godard, and Á. Sánchez-Monge. "Chemical modeling of internal photon-dominated regions surrounding deeply embedded HC/UCHII regions." Astronomy & Astrophysics 617 (September 2018): A60. http://dx.doi.org/10.1051/0004-6361/201730639.

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Aims. We aim to investigate the chemistry of internal photon-dominated regions (PDRs) surrounding deeply embedded hypercompact (HC) and ultracompact (UC) HII regions. We search for specific tracers of this evolutionary stage of massive star formation that can be detected with current astronomical facilities. Methods. We modeled hot cores with embedded HC/UCHII regions (called HII region models in the article despite the fact that we do not model the HII region itself), by coupling the astrochemical code Saptarsy to a radiative transfer framework obtaining the spatio-temporal evolution of abundances as well as time-dependent synthetic spectra. In these models where we focused on the internal PDR surrounding the HII region, the gas temperature is set to the dust temperature and we do not include dynamics thus the density structure is fixed. We compared this to hot molecular core (HMC) models and studied the effect on the chemistry of the radiation field which is included in the HII region models only during the computation of abundances. In addition, we investigated the chemical evolution of the gas surrounding HII regions with models of different densities at the ionization front, different sizes of the ionized cavity and different initial abundances. Results. We obtain the time evolution of synthetic spectra for a dozen of selected species as well as ratios of their integrated intensities. We find that some molecules such as C, N2H+, CN, and HCO do not trace the inner core and so are not good tracers to distinguish the HII/PDR regions to the HMCs phase. On the contrary, C+ and O trace the internal PDRs, in the two models starting with different initial abundances, but are unfortunately currently unobservable with the current achievable spatial resolution because of the very thin internal PDR (Δ rPDR < 100 AU). The emission of these two tracers is very dependent on the size of the HII region and on the density in the PDR. In addition, we find that the abundance profiles are highly affected by the choice of the initial abundances, hence the importance to properly define them.
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O'Dell, C. R. "Comparison of turbulence in HII regions and molecular clouds." Symposium - International Astronomical Union 147 (1991): 476–79. http://dx.doi.org/10.1017/s0074180900240072.

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Both the HII Regions and the Molecular Clouds show broadening of their emission lines beyond that expected from thermal motion and this is ascribed to turbulence. Turbulence in molecular clouds generally agrees with a model where the velocity of motion is determined by the Alfv én velocity.Turbulence in Galactic HII Regions and Giant Extragalactic HII Regions can also be studied by the width of the emission lines. The magnitude of the turbulent velocities in these regions are characteristically about 10 km/s. There is a general increase in turbulent velocity with the size of the HII Region, and this relation is close to but different from the one third power dependence expected from the most naive application of Kolmogorov theory. When a detailed study is conducted of each Galactic HII Region by means of the structure function, one finds that there is not agreement with Kolmogorov theory.The Size-Turbulent versus Velocity relation for Galactic HII Regions differs slightly from the better defined velocity relation for Giant Extragalactic HII Regions. This difference is probably due to the fact that the larger extragalactic objects are probably complexes of multiple individual HII Regions. There is no evidence that broadening of extragalactic HII Regions is due to motion about a common center of mass.
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Dissertations / Theses on the topic "HII regions"

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Steggles, Harrison. "Ultra-compact HII regions." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/15813/.

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In this thesis I have studied hydrodynamical models of cometary HII regions and distributions of UCHII regions in simulated surveys, for comparison with CORNISH. I present the numerical method used to model the evolution of cometary HII regions produced by ZAMS stars of O and B spectral types, which are driving strong winds and are born off-centre from spherically symmetric cores with power-law (alpha = 2) density slopes. A model parameter grid was produced that spans stellar mass, age and core density. Exploring this parameter space I investigated limb-brightening, a feature commonly seen in cometary HII regions. It was found that all of the models produce this feature. The models have a cavity, bounded by a contact discontinuity separating hot shocked wind and ionised ambient gas, that is similar in size to the surrounding HII region. Due to early pressure confinement, shocks outside of the contact discontinuity were not seen, but the cavities were found to continue to grow. The cavity size in each model plateaus as the expansion of the HII region stagnates, which could be due to the Kelvin-Helmholtz instabilities at the interface mixing in cooler gas. SEDs of the models are similar to those from identical stars evolving in uniform density fields. The turn-over frequency is lower in the power-law models due to a higher proportion of low density gas covered by the HII regions. Following from this I have simulated CORNISH surveys for stars, varying the local density at the location of stellar birth. I have shown that the models used can reproduce the observed size and flux distributions in the CORNISH survey. Higher density environments generally lead to better fits to the observed size and flux distributions. A good match between the overall number of UCHII regions in the simulated surveys for a SFR = 1.5 solar masses per year can be achieved if it is considered that stars are born in a distribution of local densities rather than a single density.
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Giannakopoulou, Creighton Jean. "Molecular gas in HII regions of M101." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0014/NQ30597.pdf.

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Doherty, Ruth Mary. "Infrared spectroscopy of HII regions and starburst galaxies." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/27920.

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Observations of UCHII regions shown that HII region models with electron densities of ne = 104cm-3, electron temperatures in the range Te = 5,000-10,000K and a Galactic helium abundance can reproduce the observed HeI 2.058μm/Brγ ratios in these objects, subject to one condition. As the electron temperature is increased from Te=5,000K, microturbulence is incorporated into the model which counteracts the increase in the HeI 2.058μm/Brγ ratio with electron temperature. Microturbulent velocities of the order ~20kms-1 are required at Te=10,000K, in agreement with observed radio recombination line and high resolution HeI and HI measurements. Lower HeI 2.058μm/Brγ ratios are generally found in larger objects classed as compact HII regions, consistent with lower electron densities or lower stellar effective temperatures, or a combination of both effects in such objects. Alternative electron densities have been calculated from radio continuum measurements and provide evidence to suggest that electron densities are slightly lower in most of the compact HII regions than in the UCHII regions. Detailed density gradient modelling of the HeI 2.058μm/Brγ ratio has been performed, which reveals the need for realistic density distributions and explicit integration over the volume of the source when attempting to model specific HII regions. Accurate integrated electron densities or density gradients act as an alternative to microturbulence to bring theoretical HeI 2.058μm/Brγ ratios into agreement with observations for electron temperature models higher than Te = 5,000K. Finally, a large sample of starburst galaxies is analysed. The HeI 2.058μm/Brγ ratios are much lower than found in compact or UCHII regions consistent with the proposal that the integrated HeI 2.058μm/Brγ emission is generally dominated by low density giant HII regions present in these galaxies. Effective temperatures derived from the HeI 2.058μm/Brγ ratio are consistent with those estimated from FIR fine structure lines. From consideration of new models of the HeI 2.058μm/Brγ ratio, the combination of optical HeI/Hβ data with HeI 2.058μm/Brγ observations extends the sensitivity of these model ratios to a wider range of effective temperatures.
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Bosch, G. "Giant extragalactic HII regions : 30 Doradus and beyond." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596793.

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This thesis aims to study both the stellar and the gaseous components of a sample of GEHRs and analyse the possible mechanisms that govern these forming regions. As there are no giant HII regions in our Galaxy, GEHRs from our Local Group of galaxies provide us with the data needed to understand these regions. Much has been done in this direction, and I review the latest efforts and our current knowledge in Chapter 1. Chapter 2 is focused on the analysis of the stellar population of the object that can better help us to understand GEHRs: 30 Doradus, our closest and largest neighbouring starburst. I have performed spectral classification over 175 stars in the region which allowed me to study their spatial distribution and combine with new photometry to estimate the initial mass function (IMF) and the star formation history of the stellar cluster. The results indicate a normal IMF and the existence of three distinct bursts of star formation. I also discuss the evidence found towards and against mass segregation of stars in the cluster. I have used a subset of the mentioned spectroscopic data to study the kinematics of the stars in 30 Doradus in Chapter 3. From the data I found evidence of partial dynamical mass segregation supporting the findings of the previous chapter. Assuming the cluster is virialised, I have also estimated its dynamical mass, and found it to be several times larger than the one estimated photometrically. However, more and higher resolution spectra are needed to better constrain the final value. In Chapter 4 I investigate the effect that an underlying population of binary stars could introduce in the kinematical analysis mentioned above. I have used Monte Carlo techniques to construct an artificial population of binary stars, and simulated observations of such a population to measure its kinematical parameters.
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Obonyo, Willice Odhiambo. "Open clusters and HII regions of our Galaxy." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/19997.

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Open clusters are essential laboratories for understanding stellar evolution, as they allow constraints to be placed on stellar ages and luminosities. As distance indicators they are also important tracers of star formation in the Milky Way. One such cluster is Trumpler 27 that we identified for detailed study.The aim of the study is to estimate the distance, radial velocity, age, membership and reddening of the cluster using both spectroscopic and photometric techniques. We used new spectroscopic data collected from SAAO's 1.9m telescope together with existing photometric data from catalogues in the study of Trumpler 27. The spectra collected were classified using spectral atlases to determine the reddening in the field. Stars of the cluster were identified using selection techniques that made use of both infrared and optical Q parameters, spatial distribution and photometric techniques. The result from this work suggest that Trumpler 27 is made up of ~ 55 stars which are at different stages of evolution. The stars include main sequence stars, blue supergiants, two cool supergiants and maybe two WR stars.
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Kerton, Charles Robert. "Multiwavelength studies of dust associated with galactic HII regions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ49819.pdf.

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Tibaldo, Riccardo. "Caratteristiche principali di emissione di regioni HII." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14089/.

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Si trattano le caratteristiche principali di regioni HII. Un particolare approfondimento viene condotto ai processi di generazione di fotoni, come emissione free-free, free-bound e bound-bound, e di interazione con la materia nei processi di estinzione. Dopodiché si impostano le equazioni di equilibrio: termico e di ionizzazione. Inoltre vengono forniti tre esempi di spettri in modo tale da verificare empiricamente i risultati teorici. Un capitolo finale è riservato allo studio delle abbondanze chimiche e del caso particolare delle Ultra-Compact HII.
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Costa, Allison Hainline. "A study of magnetic fields in HII regions using Faraday rotation." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6085.

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Massive young stars dynamically modify their surroundings, altering their stellar nurseries and the gas that exists between stars. With my research, I assess the modification of the Galactic magnetic field within HII regions and stellar bubbles associated with OB stars. Because HII regions are plasmas, magnetic fields should be important to the dynamics of the region. Understanding how the magnetic field is modified in these structures is critical for inputs to simulations and for assessing stellar feedback. To obtain information on the properties of the magnetic field, I measure the Faraday rotation of linearly polarized radio waves that pass through the plasma of the HII region. In this thesis, I present results of Faraday rotation studies of two Galactic \HII regions. The first is the Rosette Nebula (l = 206 deg, b = -1.2 deg), and the second is IC 1805 (l = 135 deg, b = 0.9 deg), which is associated with the W4 Superbubble. I measure positive rotation measure (RM) values in excess of +40 to +1200 rad m^-2 due to the shell of the Rosette nebula and a background RM of +147 rad m^-2 due to the general interstellar medium in this area of the Galactic plane. In the area of IC 1805, I measure negative RM values between +600 and --800 rad m^-2 due to the HII region. The sign of the RM across each HII region is consistent with the expected polarity of the large-scale Galactic magnetic field that follows the Perseus spiral arm in the clockwise direction, as suggested by Van Eck et al. (2011, ApJ, 728, 14). I find that the Rosette Nebula and IC 1805 constitute a "Faraday rotation anomaly", or a region of increased RM relative to the general Galactic background value. Although the RM observed on lines of sight through the region vary substantially, the |RM| due to the nebula is commonly 100 -- 1000 rad m^-2. In spite of this, the observed RMs are not as large as simple, analytic models of magnetic field amplification in HII regions (such as by magnetic flux conservation in a swept-up shell) might indicate. This suggests that the Galactic field is not increased by a substantial factor within the ionized gas in an HII region. Finally, these results show intriguing indications that some of the largest values of |RM| occur for lines of sight that pass outside the fully ionized shell of the IC 1805 HII region, but pass through the Photodissociation Region (PDR) associated with IC 1805.
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Vigil, Miquela 1981. "Star formation in the HII regions RCW 38, RCW 36, and RCW 108." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28615.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2004.
"June 2004."
Includes bibliographical references (leaves 41-42).
I present 1.2 mm observations of the HII regions RCW 38, RCW 36, and RCW 108 which reveal the distributions of dust associated with the three regions. The dust emission in RCW 38 exhibits a ring like structure centered around an O-star. A bright knot in the ring was determined to contain 15% of the total dust by mass in the region and roughly coincided with regions of high emission at various infrared wavelengths as well as 6 cm continuum emission. The dust emission in RCW 36 extended along a ridge with a bright clump in the north of the ridge containing 70% of the mass of the entire cluster. The dust emission in RCW 108 is concentrated in a single tight knot with a faint extension to the south. The dust emission is compared to the infrared and radio emissions to attempt to describe the characteristics of possible areas of active star formation.
Miquela Vigil.
S.M.
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Rauber, Aline Beatriz. "Catálogo de dados espectroscópicos de regiões hii e estudos aplicados." Universidade Federal de Santa Maria, 2009. http://repositorio.ufsm.br/handle/1/9196.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Quantitative measurements of line intensities have been made since the beginning of the last century. The quantity and quality of the data available have increased drastically with the advent of electronic detectors. However, the data are widely scattered in the literature. In face of this, we compiled a catalog of emission-lines intensities. It contains data on HII regions in 41 galaxies, all totaling approximately 36 000 line intensities. We have constructed a table with 1 750 emission-lines observed, showing their transition probabilities and configurations or terms. We have standardized the identification of all the emission-lines of the catalog based on this table. The database was used for different studies. We checked the values of the ratios [OIII] λ5007/λ4959 and [NII] λ6583/λ6548 with the emission-line ratios from the HII regions in the catalog. The values found are in agreement with the theoretical ones. With the diagram λ6717/Hβ versus λ6731/Hβ, we verified that most of the objets in the catalog are near the low-density limit. We also present a comparison of different temperature indicators based on observational data from HII regions, HII galaxies and planetary nebulae extracted from the literature. We have found that there is not a unique relation between the temperature indicators of different ionization zones which allows a reliable derivation of one of these from another. We have constructed diagnostic diagrams comparing the emission-lines ratios [OI]/Hα, [OII]/Hβ, [OIII]/Hβ, [NII]/Hα, [SII]/Hα e [OII]/[OIII]. For them, we have distinguished the emission-line ratios of HII regions of different galaxies and, for data from our galaxy, we have distinguished different objects. We described the diagnostic diagrams using theoretical grids varying the ionization parameter and the chemical abundance. These were computed using a photoionization code and different spectral energy distributions. With the diagram [NII]/[OII] versus [OIII]/[OII], we have obtained the best separation between ionization parameter and metallicities. We observed large discrepancies between the chemical abundances of the grids of models and those determined from collisionaly excited lines.
Medidas quantitativas de intensidades de linhas de emissão têm sido feitas desde o in´ıcio do século passado. A quantidade e a qualidade dos dados disponíveis têm crescido drasticamente com o advento dos detectores eletrônicos. Porém, os dados estão amplamente espalhados na literatura. Diante disso, compilamos um catálogo de intensidades de linhas de emissão. Este contém dados de regiões HII de 41 galáxias, totalizando aproximadamente 36 000 intensidades de linhas. Construímos uma tabela com 1 750 linhas de emissão observadas, apresentando suas probabilidades de transição e configurações ou termos. Padronizamos a identificação de todas as linhas de emissão do catálogo com base nessa tabela. O banco de dados foi utilizado para diferentes estudos. Checamos os valores das razões [OIII] λ5007/λ4959 e [NII] λ6583/λ6548 com razões de linhas de emissão de regiões HII do catálogo. Os valores encontrados concordam com os teóricos. Com o diagrama λ6717/Hβ versus λ6731/Hβ, verificamos que a maior parte dos objetos do catálogo estão próximos ao limite de baixa densidade. Apresentamos também uma comparação de diferentes indicadores de temperatura baseada em dados observacionais de regiões HII, de galáxias HII e de nebulosas planetárias extraídos da literatura. Encontramos que não há uma única relação entre indicadores de temperaturas de diferentes zonas de ionização que permita uma derivação confiável de uma destas a partir da outra. Construímos diagramas de diagnóstico comparando as razões de linhas [OI]/Hα, [OII]/Hβ, [OIII]/Hβ, [NII]/Hα, [SII]/Hα e [OII]/[OIII]. Para eles, distinguimos as razões de linhas de emissão de regiões HII de galáxias diferentes e, para os dados de nossa galáxia, distinguimos os diferentes objetos. Descrevemos os diagramas de diagnóstico utilizando grades teóricas variando o parâmetro de ionização e a metalicidade. Estas foram calculadas usando um código de fotoionização e diferentes distribuições espectrais de energia. Com o diagrama [NII]/[OII] versus [OIII]/[OII], obtivemos a melhor separação entre o parâmetro de ionização e a metalicidade. Verificamos grandes discrep ancias entre as abundâncias químicas das grades de modelos e aquelas determinadas de linhas excitadas colisionalmente.
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Books on the topic "HII regions"

1

Kerton, Charles Robert. Multiwavelength studies of dust associated with galactic HII regions. Toronto: Graduate Department of Astronomy, University of Toronto, 2000.

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Verner, Ekaterina. Fe II emission from HII regions and active galactic nuclei. Toronto: Graduate Department of Astronomy, University of Toronto, 2000.

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Roelfsema, Pieter Roelf. Radio recombination line observations of HII regions and planetary nebulae. Groningen, The Netherlands: Rijkuniversiteit te Groningen, 1987.

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Z, Scoville N., and United States. National Aeronautics and Space Administration., eds. Far-infrared emission, gas, and ultraluminous HII regions in M101: Final technical report. [Washington, DC: National Aeronautics and Space Administration, 1992.

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Z, Scoville N., and United States. National Aeronautics and Space Administration., eds. Far-infrared emission, gas, and ultraluminous HII regions in M101: Final technical report. [Washington, DC: National Aeronautics and Space Administration, 1992.

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Z, Scoville N., and United States. National Aeronautics and Space Administration., eds. Far-infrared emission, gas, and ultraluminous HII regions in M101: Final technical report. [Washington, DC: National Aeronautics and Space Administration, 1992.

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Fred, Lester Daniel, and Ames Research Center, eds. Star formation in the inner galaxy: A far-infrared and radio study of two HII regions. Moffett Field, Calif: National Aeronautics and Space Administration, Ames Research Center, 1985.

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United States. National Aeronautics and Space Administration., ed. UV extinction and IR emission in diffuse HII regions: Final technical report, August 15, 1991 - August 14, 1994. [Washington, DC: National Aeronautics and Space Administration, 1994.

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Platt, Lucy. HIV epidemics in the European region: Vulnerability and response. Washington, DC: World Bank Group, 2015.

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Ryan, Lorna. Desperately seeking services?: A directory of HIV/AIDS services for women in the Thames regions. (London): Health Education Authority, 1991.

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Book chapters on the topic "HII regions"

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Carraro, Giovanni. "HII Regions." In UNITEXT for Physics, 223–53. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-75293-4_11.

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Shapiro, Paul R., Ira Wasserman, and Mark L. Giroux. "Cosmological HII Regions." In Dark Matter in the Universe, 366. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-4772-6_76.

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Kurtz, Stan. "Ultracompact HII Regions." In Encyclopedia of Astrobiology, 1–5. Berlin, Heidelberg: Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-642-27833-4_5505-1.

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Kurtz, Stan. "Ultracompact HII Regions." In Encyclopedia of Astrobiology, 3129–33. Berlin, Heidelberg: Springer Berlin Heidelberg, 2023. http://dx.doi.org/10.1007/978-3-662-65093-6_5505.

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Chu, You-Hua, and Robert C. Kennicutt. "Internal Motions of HII Regions and Giant HII Regions." In Kinematics and Dynamics of Diffuse Astrophysical Media, 253–62. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0926-0_42.

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Gordon, Mark A. "HII Regions and Radio Recombination Lines." In Astronomy and Astrophysics Library, 37–94. New York, NY: Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4612-3936-9_2.

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Pagel, B. E. J. "Helium in HII Regions and Stars." In The Light Element Abundances, 155–64. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-540-49169-9_23.

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Handa, Toshihiro, and Yoshiaki Sofue. "The Scutum Ring of Hii Regions." In Third Asian-Pacific Regional Meeting of the International Astronomical Union, 127–30. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4630-9_29.

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Yoshida, S., M. Nakano, T. Kogure, T. Sasaki, S. D. Wiramihardja, S. Mizuno, and K. Sakka. "Surface Photometry of Simple Hii Regions." In Third Asian-Pacific Regional Meeting of the International Astronomical Union, 131–33. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4630-9_30.

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Roger, R. S., and P. E. Dewdney. "Evolutionary Models of the Dissociation Zones Surrounding HII Regions." In Star Forming Regions, 203–4. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-4782-5_79.

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Conference papers on the topic "HII regions"

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Kuchar, Thomas. "Infrared emission of Galactic Hii regions." In Back to the Galaxy. AIP, 1992. http://dx.doi.org/10.1063/1.43983.

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Stecklum, B., T. L. Hayward, M. Feldt, and M. Löwe. "ADONIS Disclosure of Ultracompact HII Regions." In Adaptive Optics. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/adop.1995.pd7.

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Peron, Giada. "Gamma-ray observations of nearby HII regions." In 7th Heidelberg International Symposium on High-Energy Gamma-Ray Astronomy. Trieste, Italy: Sissa Medialab, 2023. http://dx.doi.org/10.22323/1.417.0039.

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Mori, Tamami. "AKARI Near-Infrared Spectroscopy of Galactic HII regions." In The Life Cycle of Dust in the Universe: Observations, Theory, and Laboratory Experiments. Trieste, Italy: Sissa Medialab, 2014. http://dx.doi.org/10.22323/1.207.0111.

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Cesaroni, Riccardo. "Continuum emission from HII regions and dusty molecular clouds." In 2nd MCCT-SKADS Training School. Radio Astronomy: fundamentals and the new instruments. Trieste, Italy: Sissa Medialab, 2009. http://dx.doi.org/10.22323/1.065.0004.

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Doney, Kirstin, Xander Tielens, Takashi Onaka, Tamami Mori, and Alessandra Candian. "THE INFRARED DETECTION OF DEUTERATED PAHS IN HII REGIONS." In 71st International Symposium on Molecular Spectroscopy. Urbana, Illinois: University of Illinois at Urbana-Champaign, 2016. http://dx.doi.org/10.15278/isms.2016.rh13.

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Topchieva, A. P. "DETERMINATION OF PHYSICAL PARAMETERS OF INFRARED RADIATION IN HII REGIONS." In 48-th International student's conferences "Physics of Space". Ural University Press, 2020. http://dx.doi.org/10.15826/b978-5-7996-2935-9.79.

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Higdon, J. C. "Cosmic ray path length distributions from superbubble/giant HII regions." In Acceleration and transport of energetic particles observed in the heliosphere (ACE-2000 symposium). AIP, 2000. http://dx.doi.org/10.1063/1.1324353.

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Wyithe, Stuart, Paul Geil, and Hansik Kim. "Imaging HII Regions from Galaxies and Quasars During Reionisation with SKA." In Advancing Astrophysics with the Square Kilometre Array. Trieste, Italy: Sissa Medialab, 2015. http://dx.doi.org/10.22323/1.215.0015.

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Topchieva, A. P. "SPECTRAL TYPES OF IONIZING STARS AND THE INFRARED MORPHOLOGY OF HII REGIONS." In 48-th International student's conferences "Physics of Space". Ural University Press, 2020. http://dx.doi.org/10.15826/b978-5-7996-2935-9.78.

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Reports on the topic "HII regions"

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Low, Mordecai-Mark Mac, Jayashree Toraskar, Jeffrey S. Oishi, and Tom Abel. Dynamical Expansion of HII Regions From Ultracompact to Compact Sizes in Turbulent, Self-Gravitating Molecular Clouds. Office of Scientific and Technical Information (OSTI), May 2006. http://dx.doi.org/10.2172/882832.

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O'Shea, Brian. Forming a Primordial Star in a Relic HII Region. Office of Scientific and Technical Information (OSTI), April 2005. http://dx.doi.org/10.2172/839853.

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Lopez Bautista, Cesar. Large scale MD to predict Epitope regions in HIV Env. Office of Scientific and Technical Information (OSTI), January 2022. http://dx.doi.org/10.2172/1841887.

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Busza, Joanna. Literature review: Challenging HIV-related stigma and discrimination in Southeast Asia: Past successes and future priorities. Population Council, 1999. http://dx.doi.org/10.31899/hiv1999.1001.

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Pervasive stigma has surrounded HIV/AIDS since the beginning of the pandemic. In Southeast Asia, as elsewhere, it has been accompanied by discrimination, affecting transmission patterns and access to care and support. This paper describes the regional experience of stigma and discrimination and offers a review of community-based interventions that have attempted to reduce them. The evidence presented comes primarily from unpublished literature and anecdotal evidence gained through interviews with project staff throughout the region.
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Ruamtawee, Witchakorn, Mathuros Tipayamongkholgul, Natnaree Aimyong, and Weerawat Manosuthi. Prevalence and Risk Factors of Cardiovascular Disease among People Living with HIV in the Asia-Pacific Region: a systematic review. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, September 2022. http://dx.doi.org/10.37766/inplasy2022.9.0108.

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Review question / Objective: This systematic review was conducted to address the situation and associated factors both traditional and HIV-specific for CVD among adult people living with HIV who were aged ≥ 18 years in the Asia Pacific region, and focused only on the counties with the greatest impact of CVD attributable to HIV infection including Bhutan, Cambodia, Indonesia, Malaysia, Myanmar, Papua New Guinea, Solomon Islands, and Thailand in the HAART era since 2005. Information sources: This systematic review was performed in an attempt to retrieve epidemiological studies of CVD among PLHIV in the greatest impact of CVD attributable to HIV countries in the Asia Pacific region from the following sources: • MEDLINE via PubMed (https://www.ncbi.nlm.nih.gov/pubmed) • Embase (https://www.embase.com) • the Cochrane Database of Systematic Reviews (https://www.cochranelibrary.com).
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Pradelli, Juan Jose, Kimberly Waithe, Allan Wright, Dillon Clarke, Jeetendra Khadan, Juan Pedro Schmid, and Mark D. Wenner. Caribbean Region Quarterly Bulletin: Commodities in the Caribbean: Volume 6: Issue 2: June 2017. Inter-American Development Bank, June 2017. http://dx.doi.org/10.18235/0008152.

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This issue of the Caribbean Region Quarterly Bulletin explores the importance of commodities for the region’s countries. While the Caribbean includes commodity producers, most members depend heavily on energy imports. The fall in oil prices was a huge relief for these countries, improving the external position, keeping prices stable and increasing the purchasing power for households. At the same time, Suriname and Trinidad and Tobago were hit hard with falls in exports, revenues, and economic contractions. As usual, the Quarterly Bulletin also covers recent economic developments in The Bahamas, Barbados, Guyana, Jamaica, Suriname, and Trinidad and Tobago, and includes a section on the Organisation of Eastern Caribbean States (OECS).
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Kjellander, Tove, and Lisa Sjöblom. Child and youth participation during crisis – Recommendations for decision makers in the Nordic region. Edited by Merethe Löberg and Christina Lindström. Nordic Welfare Centre, March 2023. http://dx.doi.org/10.52746/okta3233.

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Every young person is entitled to be heard and involved in matters that concern them. But how can decision makers safeguard meaningful child and youth participation in times of crisis? This publication contains 34 recommendations and 9 promising examples for decision makers in the Nordic region on how to build resilient structures for the future. The analysis and recommendations in this report are based on conversations with more than 100 representatives of youth and national experts in the Nordic region, covering the Nordic countries and Greenland, Åland and the Faroe Islands. The lessons and direct experiences of the representatives of Nordic youth organisations serve as an important source of information in preparing for potential crises in the future. The learnings are valuable for all adults making decisions that concerns young, and especially important for decision makers responsible for any crisis management structures. Decision makers in the Nordic region were not prepared to protect children’s rights when the Covid-19 pandemic hit. Their right to be heard was often neglected or recognised too late. To do better in a future crisis we need to have participatory structures in place before the crisis hits. Children and young people don’t have as much power as adults, and they cannot yet vote. We also need decision makers that have positive attitudes toward children and youth, necessary skills, and competence. Decision makers should presume that a child has the capacity to form her or his own views and recognize that she or he has the right to express them. We encourage local authorities and decision makers in the Nordic region to use the checklist in the publication to build resilient structures for child and youth participation. If a new crisis strikes, the Nordic region must ensure that the perspectives and experiences of children and youth are included in the decision making processes.
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Wiseman, Patrick, and Michael O’Riordan. Pericapsular Nerve Group (PENG) Block - An Evidence Based Discussion. World Federation of Societies of Anaesthesiologists, August 2022. http://dx.doi.org/10.28923/atotw.478.

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This tutorial explores the Pericapsular Nerve (PENG) Block, a novel regional anaesthesia technique which has been suggested as an alternative to existing blocks to reduce pain following hip fractures and hip surgery.
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Viola, Cintia. Will High Representative Christian Schmidt be Able to Untie the Bosnian Knot? Külügyi és Külgazdasági Intézet, 2021. http://dx.doi.org/10.47683/kkielemzesek.ke-2021.56.

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The nomination and eventual appointment of the new High Representative (HR) of Bosnia and Herzegovina, Christian Schmidt, explains Germany’s support, given his experience and knowledge of the region. However, the HR is facing the same challenges as his predecessors: a lack of consensus among international actors, rising nationalism, the impossibility of constitutional reforms, and an unstable internal political situation.
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Rossi, José Luiz, and João Paulo Madureira Horta da Costa. Shock Dependent Exchange Rate Pass-Through - An Analysis for Latin American Countries. Inter-American Development Bank, September 2023. http://dx.doi.org/10.18235/0005129.

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This paper investigates the exchange rate pass through considering the source of the shocks that hit the economy. With a Bayesian Global VAR model, the exchange rate pass-through is analyzed for 5 Latin American countries: Brazil, Chile, Colombia, Mexico and Peru. The model is estimated with Bayesian techniques and is identified by sign and zero restrictions. The BGVAR estimation enable us to allow spillover between countries mimicking the real conditions when the shocks hit the economies. Four domestic shocks for each Latin American countries are considered: an exchange rate shock, a risk premium shock, a monetary policy shock and a demand shock. The demand shock has the highest exchange rate pass-through for all the countries and the exchange rate shock has the lowest one. Additionally, two regional shocks are considered: a regional monetary policy shock, an event that all the region rises its interest rate and a regional risk premium shock, where the risk premium rises at the same time. For almost of the countries, the exchange rate pass-through coming from those regional shocks are lower than its domestic counterpart shock. Finally, we investigate two global shocks, an uncertainty shock and a global commodities/demand shock. The uncertainty shock decreases the economic activity and depreciates the exchange rate with a negative exchange rate pass-through in the middle term. The commodities/demand shock increases the economic activity and appreciates the exchange rate passthrough, having a negative or neutral exchange rate pass-through over the time.
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