Sample records for giant hii regions

  1. On the structure of giant HII regions and HII galaxies

    Tenorio-Tagle, G; Pérez, E; Silich, S; Telles, E


    We review the structural properties of giant extragalactic HII regions and HII galaxies based on two dimensional hydrodynamic calculations, and propose an evolutionary sequence that accounts for their observed detailed structure. The model assumes a massive and young stellar cluster surrounded by a large collection of clouds. These are thus exposed to the most important star-formation feedback mechanisms: photoionization and the cluster wind. The models show how the two feedback mechanisms compete with each other in the disruption of clouds and lead to two different hydrodynamic solutions: The storage of clouds into a long lasting ragged shell that inhibits the expansion of the thermalized wind, and the steady filtering of the shocked wind gas through channels carved within the cloud stratum that results into the creation of large-scale superbubbles. Both solutions are here claimed to be concurrently at work in giant HII regions and HII galaxies, causing their detailed inner structure. A full description of t...

  2. On the feedback from super stellar clusters. I. The structure of giant HII regions and HII galaxies

    Tenorio-Tagle, G; Pérez, E; Silich, S; Telles, E


    We review the structural properties of giant extragalactic HII regions and HII galaxies based on 2D hydrodynamic calculations, and propose an evolutionary sequence that accounts for their observed detailed structure. The model assumes a massive and young stellar cluster surrounded by a large collection of clouds. These are thus exposed to the most important star-formation feedback mechanisms: photoionization and the cluster wind. The models show how the two feedback mechanisms compete in the disruption of clouds and lead to two different hydrodynamic solutions: The storage of clouds into a long lasting ragged shell that inhibits the expansion of the thermalized wind, and the steady filtering of the shocked wind gas through channels carved within the cloud stratum. Both solutions are claimed to be concurrently at work in giant HII regions and HII galaxies, causing their detailed inner structure. This includes multiple large-scale shells, filled with an X-ray emitting gas, that evolve to finally merge with each...

  3. Two physical regimes for the Giant HII Regions and Giant Molecular Clouds in the Antennae Galaxies

    Zaragoza-Cardiel, Javier; Beckman, John E; García-Lorenzo, Begoña; Erroz-Ferrer, Santiago; Gutiérrez, Leonel


    We have combined observations of the Antennae galaxies from the radio interferometer ALMA (Atacama Large Millimetre/submillimetre Array) and from the optical interferometer GH$\\alpha$FaS (Galaxy Halpha Fabry-Perot System). The two sets of observations have comparable angular and spectral resolutions, enabling us to identify 142 giant molecular clouds and 303 HII regions. We have measured, and compare, their basic physical properties (radius, velocity dispersion, luminosity). For the HII regions we find two physical regimes, one for masses $>10^{5.4} \\mathrm{M_{\\odot}}$ of ionized gas, which the gas density increases with gas mass, the other for masses $<10^{5.4} \\mathrm{M_{\\odot}}$ of ionized gas where the gas density decreases with gas mass. For the GMCs we find, in contrast to previous studies in other galaxies over a generally lower mass range of clouds, that the gas density increases with the total gas mass, hinting at two regimes for these clouds if we consider both sources of data. We also find that ...

  4. Properties of the giant HII regions and bar in the nearby spiral galaxy NGC5430

    Brière, É; Spekkens, K


    In order to better understand the impact of the bar on the evolution of spiral galaxies, we measure the properties of giant HII regions and the bar in the SB(s)b galaxy NGC5430. We use two complementary data sets, both obtained at the Observatoire du Mont-M\\'egantic: a hyperspectral data cube from the imaging Fourier transform spectrograph SpIOMM, and high-resolution spectra across the bar from a long-slit spectrograph. We flux-calibrate SpIOMM spectra for the first time, and produce H{\\alpha} and [NII]{\\lambda}6584\\r{A} intensity maps from which we identify 51 giant HII regions in the spiral arms and bar. We evaluate the type of activity, the oxygen abundance and the age of the young populations contained in these giant HII regions and in the bar. Thus, we confirm that NGC5430 does not harbour a strong AGN, and that its Wolf-Rayet knot shows a pure HII region nature. We find no variation in abundance or age between the bar and spiral arms, nor as a function of galactocentric radius. These results are consist...

  5. Discovery of radiatively excited molecular hydrogen in the giant extragalactic HII region complex NGC 604

    Israel, F.P.; Hawarden, T.G.; Wade, R.S.; Geballe, T.R.; Dishoeck, van E.F.


    The 1-0S(1), 2-1S(1), 1-0S(0) and 1-0Q branch transitions of molecular hydrogen (H2) towards the giant emission nebula (HII region) NGC 604 in M33 have been detected. The line ratios are incompatible with shock-excited H2, but indicate the widespread presence of fluorescent H2 at a mean temperature

  6. Unresolved wind-driven shells and the supersonic velocity dispersion in giant HII regions

    Tenorio-Tagle, G; Fernandes, R C; Fernandes, R Cid


    The presence of giant shells or loops in giant HII regions are clear witness of the mechanical energy input from massive stars. Here we evaluate the impact that winds may have on the structure of giant nebulae and on their supersonic velocity dispersion. We follow the suggestion from Chu \\& Kennicutt (1994) to see if a combination of a large number of unresolved wind-driven shells caused by massive stars could produce the integrated broad Gaussian profiles typical of giant HII regions. The results, accounting for a wide range of energies, densities and velocity or age of the expanding shells, show that supersonic Gaussian profiles may arise only from a collection of unresolved wind-driven shells if the shells present a peculiar velocity distribution which implies a strongly peaked age distribution leading to an awkward star formation history. On the other hand, a uniform distribution of ages originates profiles with a flat-topped core defined by the terminal shell velocity and a steep decay as v^{-6} up t...

  7. An MSX Infrared Analysis of the Superbubble around Giant HII Region NGC3603

    Wang, Jia


    Using the MSX mid-infrared observation, we reveal a 100 pc-scale superbubble surrounding the giant HII region NGC3603. We suggest that the diffuse surrounding infrared emission in bands A, C, and D is dominated by that of PAH and the emission in band E is dominated by that of dust grains. The fitted dust temperature is consistent with the heating by the central cluster's UV photons. The derived gas-to-dust mass ratio for the bubble shell is of order 10^2.

  8. HRM: HII Region Models

    Wenger, Trey V.; Kepley, Amanda K.; Balser, Dana S.


    HII Region Models fits HII region models to observed radio recombination line and radio continuum data. The algorithm includes the calculations of departure coefficients to correct for non-LTE effects. HII Region Models has been used to model star formation in the nucleus of IC 342.

  9. The giant HII region NGC 588 as a benchmark for 2D photoionisation models

    Perez-Montero, Enrique; Relano, Monica; Vilchez, Jose M; Kehrig, Carolina; Morisset, Christophe


    We use optical integral field spectroscopy and 8 and 24 micron mid-IR observations of the giant HII region NGC 588 in the disc of M33 as input and constraints for two-dimensional tailor-made photoionisation models. Two different geometrical approaches are followed for the modelling structure: i) Each spatial element of the emitting gas is studied individually using models which assume that the ionisation structure is complete in each element to look for azimuthal variations across gas and dust. ii) A single model is considered, and the two-dimensional structure of the gas and the dust are assumed to be due to the projection of an emitting sphere onto the sky. The models in both assumptions reproduce the radial profiles of Hbeta surface brightness, the observed number of ionising photons, and the strong optical emission-line relative intensities. The first approach produces a constant-density matter-bounded thin shell of variable thickness and dust-to-gas ratio, while the second gives place to a radiation-boun...

  10. Determining the Hubble constant using HII regions and HII galaxies

    Chavez, Ricardo; Terlevich, Roberto; Plionis, Manolis; Bresolin, Fabio; Basilakos, Spyros; Melnick, Jorge


    We report the first results of a long term program aiming to provide accurate independent estimates of the Hubble constant (H0) and the Dark Energy equation of state parameter (w) using the L(Hbeta)-velocity dispersion (sigma) distance estimator for Giant HII regions and HII galaxies. We have used VLT and Subaru high dispersion spectroscopic observations of a local sample of HII galaxies, identified in the SDSS DR7 catalogue in order to re-define and improve the L(Hbeta) - sigma distance indicator and to determine the Hubble constant. To this end we used as local calibration or 'anchor' of this correlation, giant HII regions in nearby galaxies which have accurate distance measurements determined via primary indicators. Using our best sample of 89 nearby HII galaxies and 23 Giant HII regions in 9 galaxies we obtain H0 = 73.9+- 2.7 (statistical)+- 2.9 (systematic) km s-1 Mpc-1, in excellent agreement with, and independently confirming, the most recent SNe Ia based results.

  11. ISO Mid-Infrared Observations of Giant HII Regions in M33

    Skelton, B. P.; Waller, W. H.; Hodge, P. W.; Boulanger, F.; Cornett, R. H.; Fanelli, M. N.; Lequeux, J.; Stecher, T. P.; Viallefond, F.; Hui, Y.


    We present Infrared Space Observatory Camera (ISOCAM) Circular Variable Filter scans of three giant HII regions in M33. IC 133, NGC 595, and CC 93 span a wide range of metallicity, luminosity, nebular excitation, and infrared excess; three other emission regions (CC 43, CC 99, and a region to the northeast of the core of NGC 595) are luminous enough in the mid-infrared to be detected in the observed fields. ISOCAM CVF observations provide spatially resolved observations (5'') of 151 wavelengths between 5.1 and 16.5 microns with a spectral resolution R = 35 to 50. We observe atomic emission lines ([Ne II], [Ne III], and [S IV]), several "unidentified infrared bands" (UIBs; 6.2, 7.7, 8.6, 11.3, 12.0, and 12.7 microns), and in some cases a continuum which rises steeply at longer wavelengths. We conclude that the spectra of these three GHRs are well explained by combinations of ionized gas, PAHs, and very small grains in various proportions and with different spatial distributions. Comparisons between observed ratios of the various UIBs with model ratios indicate that the PAHs in all three of the GHRs are dehydrogenated and that the small PAHs have been destroyed in IC 133 but have survived in NGC 595 and CC 93. The [Ne III]/[Ne II] ratios observed in IC 133 and NGC 595 are consistent with their ages of 5 and 4.5 Myr, respectively; the deduced ionization parameter is higher in IC 133, consistent with its more compact region of emission.

  12. ISO Mid-Infrared Observations of Giant HII Regions in M33

    Skelton, B. P.; Waller, W. H.; Hodge, P. W.; Boulanger, F.; Cornett, R. H.; Fanelli, M. N.; Lequeux, J.; Stecher, T. P.; Viallefond, F.; Hui, Y.


    We present Infrared Space Observatory Camera (ISOCAM) Circular Variable Filter scans of three giant HII regions in M33. IC 133, NGC 595, and CC 93 span a wide range of metallicity, luminosity, nebular excitation, and infrared excess; three other emission regions (CC 43, CC 99, and a region to the northeast of the core of NGC 595) are luminous enough in the mid-infrared to be detected in the observed fields. ISOCAM CVF observations provide spatially resolved observations (5'') of 151 wavelengths between 5.1 and 16.5 microns with a spectral resolution R = 35 to 50. We observe atomic emission lines ([Ne II], [Ne III], and [S IV]), several "unidentified infrared bands" (UIBs; 6.2, 7.7, 8.6, 11.3, 12.0, and 12.7 microns), and in some cases a continuum which rises steeply at longer wavelengths. We conclude that the spectra of these three GHRs are well explained by combinations of ionized gas, PAHs, and very small grains in various proportions and with different spatial distributions. Comparisons between observed ratios of the various UIBs with model ratios indicate that the PAHs in all three of the GHRs are dehydrogenated and that the small PAHs have been destroyed in IC 133 but have survived in NGC 595 and CC 93. The [Ne III]/[Ne II] ratios observed in IC 133 and NGC 595 are consistent with their ages of 5 and 4.5 Myr, respectively; the deduced ionization parameter is higher in IC 133, consistent with its more compact region of emission.

  13. The Stellar Content of Obscured Galactic Giant HII Regions. VII. W3

    Navarete, F; Damineli, A; Moisés, A P; Blum, R D; Conti, P S


    Spectrophotometric distances in the K band have been reported by different authors for a number of obscured Galactic HII regions. Almost 50% of them show large discrepancies compared to the classical method using radial velocities measured in the radio spectral region. In order to provide a crucial test of both methods, we selected a target which does not present particular difficulty for any method and which has been measured by as many techniques as possible. The W3 star forming complex, located in the Perseus arm, offers a splendid opportunity for such a task. We used the NIFS spectrograph on the Frederick C. Gillett Gemini North telescope to classify candidate "naked photosphere" OB stars based on 2MASS photometry. Two of the targets are revealed to be mid O-type main sequence stars leading to a distance of d = 2.20 kpc. This is in excellent agreement with the spectrophotometric distance derived in the optical band (d = 2.18 kpc, Humphreys 1978) and with a measurement of the W3 trigonometric parallax (d =...

  14. Optical Recombination Lines of Heavy-elements in Giant Extragalactic HII Regions

    Esteban, C; Torres-Peimbert, S; Rodríguez, M


    We present high resolution observations of the giant extragalactic H II regions NGC 604, NGC 2363, NGC 5461 and NGC 5471, based on observations taken with the ISIS spectrograph on the William Herschel Telescope. We have detected -by the first time- C II and O II recombination lines in these objects. We find that recombination lines give larger C^{++} and O^{++} abundances than collisionallly excited lines, suggesting that temperature variations can be present in the objects. We detect [Fe IV] lines in NGC 2363 and NGC 5471, the most confident detection of optical lines of this kind in H II regions. Considering the temperature structure we derive their H, He, C, N, O, Ne, S, Ar, and Fe abundances. From the recombination lines of NGC 5461 and NGC 5471 we determine the presence of C/H and O/H gradients in M101. We calculate the Delta Y/Delta O and Delta Y/Delta Z values considering the presence of temperature variations and under the assumption of constant temperature. We obtain a better agreement with models of...

  15. Finding Distant Galactic HII Regions

    Anderson, L D; Johnstone, B M; Bania, T M; Balser, Dana S; Wenger, Trey V; Cunningham, V


    The WISE Catalog of Galactic HII Regions contains $\\sim2000$ HII region candidates lacking ionized gas spectroscopic observations. All candidates have the characteristic HII region mid-infrared morphology of WISE $12\\,\\,\\mu\\,m$ emission surrounding $22\\,\\mu\\,m$ emission, and additionally have detected radio continuum emission. We here report Green Bank Telescope (GBT) hydrogen radio recombination line (RRL) and radio continuum detections at X-band (9GHz; 3cm) of 302 WISE HII region candidates (out of 324 targets observed) in the zone $225^{\\circ} > l > -20^{\\circ}$, $|b| \\le 6^{\\circ}$. Here we extend the sky coverage of our HII region Discovery Survey (HRDS), which now contains nearly 800 HII regions distributed across the entire northern sky. We provide LSR velocities for the 302 detections and kinematic distances for 131 of these. Of the 302 new detections, five have ($l, b, v$) coordinates consistent with the Outer Scutum-Centaurus Arm (OSC), the most distant molecular spiral arm of the Milky Way. Due to ...

  16. Predictions of the extent of self-enrichment in oxygen of giant metal-poor HII regions

    Wofford, Aida


    In general, HII regions do not show clear signs of self-enrichment in products from massive stars (M > 8 M_sun). In order to explore why, I modeled the contamination with Wolf-Rayet star ejecta of metal-poor (Z=0.001) HII regions, ionised either by a 10^6 M_sun cluster of coeval stars (cluster 1), or a cluster resulting from continuous star formation at a rate of 1 M_sun yr^-1 (cluster 2). The clusters have Z=0.001 and a Salpeter initial mass function (IMF) from 0.1 to 120 M_sun. Independent one dimensional constant density simulations of the emission-line spectra of unenriched HII regions were computed at the discrete ages 1, 2, 3, 4, and 5 Myr, with the photoionisation code CLOUDY, using as input, radiative and mechanical stellar feedbacks predicted by the evolutionary synthesis code STARBURST99. Each HII region was placed at the outer radius of the adiabatically expanding superbubble of Mac Low and McCray (1988). For models with thermal and ionisation balance time-scales of less than 1 Myr, and with oxygen...

  17. Star clusters and the structure of the ISM Tunnels and wakes in giant extragalactic HII regions

    Tenorio-Tagle, G; Tenorio-Tagle, Guillermo; Tanco, Gustavo Medina


    Several structures have been discovered embedded in regions of recent or ongoing star formation, which point to the importance of the interaction between fast moving wind-blowing stars and their environment. Using hydrodynamic simulations, we investigate the passage through the interstellar medium of a supersonic stellar wind source, and show how it can naturally lead to the formation of tubes, channels and swamps of globules as interfaces are crossed. The results are in excellent agreement with observation of 30 Doradus.

  18. An HST/NICMOS view of the prototypical giant HII region NGC604 in M33

    Barba, Rodolfo H; Perez, Enrique; Rubio, Monica; Bolatto, Alberto; Farina, Cecilia; Bosch, Guillermo; Walborn, Nolan R


    We present the first high-spatial resolution near-infrared (NIR) imaging of NGC 604, obtained with the NICMOS camera aboard the Hubble Space Telescope (HST). These NICMOS broadband images reveal new NIR point sources, clusters, and diffuse structures. We found an excellent spatial correlation between the 8.4 GHz radio continuum and the 2.2mu-m nebular emission. Moreover, massive young stellar object candidates appear aligned with these radio peaks, reinforcing the idea that those areas are star-forming regions. Three different scaled OB associations are recognized in the NICMOS images. The brightest NIR sources in our images have properties that suggest that they are red supergiant stars, of which one of them was previously known. This preliminary analysis of the NICMOS images shows the complexity of the stellar content of the NGC 604 nebula.

  19. An In-Depth View of the Mid-Infrared Properties of Point Sources and the Diffuse ISM in the SMC Giant HII Region, N66

    Whelan, David G; Galliano, Frederic; Peeters, Els; Bernard-Salas, Jeronimo; Johnson, Kelsey E; Indebetouw, Remy; Brandl, Bernhard


    (abridged)The focus of this work is to study mid-infrared point sources and the diffuse interstellar medium (ISM) in the low-metallicity (~0.2 solar) giant HII region N66 using the Spitzer Space Telescope's Infrared Spectrograph. We study 14 targeted infrared point sources as well as spectra of the diffuse ISM that is representative of both the photodissociation regions (PDRs) and the HII regions. Among the point source spectra, we spectroscopically confirm that the brightest mid-infrared point source is a massive embedded young stellar object, we detect silicates in emission associated with two young stellar clusters, and we observe spectral features of a known B[e] supergiant that are more commonly associated with Herbig Be stars. In the diffuse ISM, we provide additional evidence that the very small grain population is being photodestroyed in the hard radiation field. The 11.3 um PAH complex emission exhibits an unexplained centroid shift in both the point source and ISM spectra that should be investigated...

  20. The WISE Catalog of Galactic HII Regions

    Anderson, L D; Balser, Dana S; Cunningham, V; Wenger, T V; Johnstone, B M; Armentrout, W P


    Using data from the all-sky Wide-Field Infrared Survey Explorer (WISE) satellite, we made a catalog of over 8000 Galactic HII regions and HII region candidates by searching for their characteristic mid-infrared (MIR) morphology. WISE has sufficient sensitivity to detect the MIR emission from HII regions located anywhere in the Galactic disk. We believe this is the most complete catalog yet of regions forming massive stars in the Milky Way. Of the ~8000 cataloged sources, ~1500 have measured radio recombination line (RRL) or H$\\alpha$ emission, and are thus known to be HII regions. This sample improves on previous efforts by resolving HII region complexes into multiple sources and by removing duplicate entries. There are ~2500 candidate HII regions in the catalog that are spatially coincident with radio continuum emission. Our group's previous RRL studies show that ~95% of such targets are HII regions. We find that ~500 of these candidates are also positionally associated with known HII region complexes, so th...

  1. Interstellar Bubbles in Two Young HII Regions

    Naze, Y; Points, S D; Danforth, C W; Rosado, M; Chen, C H R; Naze, Yael; Chu, You-Hua; Points, Sean D.; Danforth, Charles W.; Rosado, Margarita


    Massive stars are expected to produce wind-blown bubbles in the interstellar medium; however, ring nebulae, suggesting the existence of bubbles, are rarely seen around main-sequence O stars. To search for wind-blown bubbles around main-sequence O stars, we have obtained high-resolution Hubble Space Telescope WFPC2 images and high-dispersion echelle spectra of two pristine HII regions, N11B and N180B, in the Large Magellanic Cloud. These HII regions are ionized by OB associations that still contain O3 stars, suggesting that the HII regions are young and have not hosted any supernova explosions. Our observations show that wind-blown bubbles in these HII regions can be detected kinematically but not morphologically because their expansion velocities are comparable to or only slightly higher than the isothermal sound velocity in the HII regions. Bubbles are detected around concentrations of massive stars, individual O stars, and even an evolved red supergiant (a fossil bubble). Comparisons between the observed bu...

  2. Extended emission associated with young HII regions

    Ellingsen, S P; Kurtz, S E


    We have used the Australia Telescope Compact Array (ATCA) to make observations of a sample of eight young ultra-compact HII regions, selected on the basis that they have associated class II methanol maser emission. We have made observations sensitive to both compact and extended structures and find both to be present in most sources. The scale of the extended emission in our sample is in general less than that observed towards samples based on IRAS properties, or large single-dish flux densities. Our observations are consistent with a scenario where extended and compact radio continuum emission coexists within HII regions for a significant period of time. We suggest that these observations are consistent with a model where HII evolution takes place within hierarchically structured molecular clouds. This model is the subject of a companion paper (Shabala et al. 2005) and addresses both the association between compact and extended emission and UCHII region lifetime problem.

  3. Intergalactic HII Regions Discovered in SINGG

    Ryan-Weber, E V; Freeman, K C; Putman, M E; Webster, R L; team., the SINGG


    A number of very small isolated HII regions have been discovered at projected distances up to 30 kpc from their nearest galaxy. These HII regions appear as tiny emission line objects in narrow band images obtained by the NOAO Survey for Ionization in Neutral Gas Galaxies (SINGG). We present spectroscopic confirmation of four isolated HII regions in two systems, both systems have tidal HI features. The results are consistent with stars forming in interactive debris due to cloud-cloud collisions. The H-alpha luminosities of the isolated HII regions are equivalent to the ionizing flux of only a few O stars each. They are most likely ionized by stars formed in situ, and represent atypical star formation in the low density environment of the outer parts of galaxies. A small but finite intergalactic star formation rate will enrich and ionize the surrounding medium. In one system, NGC 1533, we calculate a star formation rate of 1.5e-3 msun/yr, resulting in a metal enrichment of ~1e-3 solar for the continuous formati...

  4. Identification of ten new Galactic HII regions


    We discovered ten large HII regions in the Sino-German λ6 cm polarization survey of the Galactic plane. They have been identified according to their flat spectral indexes and the high ratio between the 60 μm infrared emission and the λ6 cm emission. The integrated flux densities as well as the sizes of these sources are given at 4800 MHz. Cross-identifications are made with other major radio catalogs.

  5. Python Program to Select HII Region Models

    Miller, Clare; Lamarche, Cody; Vishwas, Amit; Stacey, Gordon J.


    HII regions are areas of singly ionized Hydrogen formed by the ionizing radiaiton of upper main sequence stars. The infrared fine-structure line emissions, particularly Oxygen, Nitrogen, and Neon, can give important information about HII regions including gas temperature and density, elemental abundances, and the effective temperature of the stars that form them. The processes involved in calculating this information from observational data are complex. Models, such as those provided in Rubin 1984 and those produced by Cloudy (Ferland et al, 2013) enable one to extract physical parameters from observational data. However, the multitude of search parameters can make sifting through models tedious. I digitized Rubin's models and wrote a Python program that is able to take observed line ratios and their uncertainties and find the Rubin or Cloudy model that best matches the observational data. By creating a Python script that is user friendly and able to quickly sort through models with a high level of accuracy, this work increases efficiency and reduces human error in matching HII region models to observational data.

  6. The size--density relation of extragalactic HII regions

    Hunt, L K


    We investigate the size--density relation in extragalactic HII regions, with the aim of understanding the role of dust and different physical conditions in the ionized medium. First, we compiled several observational data sets for Galactic and extragalactic HII regions and confirm that extragalactic HII regions follow the same size (D)--density (n) relation as Galactic ones. Motivated by the inability of static models to explain this, we then modelled the evolution of the size--density relation of HII regions by considering their star formation history, the effects of dust, and pressure-driven expansion. The results are compared with our sample data whose size and density span roughly six orders of magnitude. We find that the extragalactic size--density relation does not result from an evolutionary sequence of HII regions but rather reflects a sequence with different initial gas densities (``density hierarchy''). Moreover, the size of many HII regions is limited by dust absorption of ionizing photons, rather ...

  7. Radio Recombination Lines in Galactic HII Regions

    Quireza, C; Bania, T M; Rood, R T; Balser, Dana S.; Quireza, Cintia; Rood, Robert T.


    We report radio recombination line (RRL) and continuum observations of a sample of 106 Galactic HII regions made with the NRAO 140 Foot radio telescope in Green Bank, WV. We believe this to be the most sensitive RRL survey ever made for a sample this large. Most of our source integration times range between 6 and 90 hours which yield typical r.m.s. noise levels of 1.0--3.5 milliKelvins. Our data result from two different experiments performed, calibrated, and analyzed in similar ways. A CII survey was made at 3.5 cm wavelength to obtain accurate measurements of carbon radio recombination lines. When combined with atomic (CI) and molecular (CO) data, these measurements will constrain the composition, structure, kinematics, and physical properties of the photodissociation regions that lie on the edges of HII regions. A second survey was made at 3.5 cm wavelength to determine the abundance of 3He in the interstellar medium of the Milky Way. Together with measurements of the 3He+ hyperfine line we get high precis...

  8. The Morphology of HII Regions during Reionization

    McQuinn, M; Zahn, O; Dutta, S; Hernquist, L; Zaldarriaga, M; Quinn, Matthew Mc; Lidz, Adam; Zahn, Oliver; Dutta, Suvendra; Hernquist, Lars; Zaldarriaga, Matias


    It is possible that the properties of HII regions during reionization depend sensitively on many poorly constrained quantities (the nature of the ionizing sources, the clumpiness of the gas in the IGM, the degree to which photo-ionizing feedback suppresses the abundance of low mass galaxies, etc.), making it extremely difficult to interpret upcoming observations of this epoch. We demonstrate that the actual situation is more encouraging, using a suite of radiative transfer simulations, post-processed on outputs from a 1024^3, 94 Mpc N-body simulation. Analytic prescriptions are used to incorporate small scale structures that affect reionization, yet remain unresolved in the N-body simulation. We show that the morphology of the HII regions is most dependent on the global ionization fraction x_i. This is not to say that the bubble morphology is completely independent of all parameters besides x_i. The next most important dependence is that of the nature of the ionizing sources. The rarer the sources, the larger...

  9. Molecular Counterparts of Ultracompact HII Regions with Extended Envelopes

    Kim, K T; Kim, Kee-Tae; Koo, Bon-Chul


    We carried out 13CO J=1-0, CS, and C34S J=2-1 and J=3-2 line observations of molecular clouds associated with 16 ultracompact (UC) HII regions with extended envelopes. The molecular clouds are the ones that give birth to rich stellar clusters and/or very massive (O7-O4) stars. Our data show that the clouds are very clumpy and of irregular morphology. They usually have much larger masses, velocity dispersions, and fractions of dense gas than molecular clouds that form early B or late O stars. This is compatible with earlier findings that more massive stars form in more massive cores. 13CO cores are in general associated with compact HII regions regardless of the presence of UC HII regions therein. In contrast, CS cores are preferentially associated with compact HII regions that contain UC HII regions. As with the fact that the compact HII regions containing UC HII regions are more compact than those not associated with UC HII regions, these indicate that the former may be in an earlier evolutionary phase than ...

  10. The HII Region of a Primordial Star

    Abel, T; Bryan, G L; Abel, Tom; Wise, John H.; Bryan, Greg L.


    The concordance model of cosmology and structure formation predicts the formation of isolated very massive stars at high redshifts in dark matter dominated halos of 10^5 to 10^6 Msun. These stars photo-ionize their host primordial molecular clouds, expelling all the baryons from their halos. When the stars die, a relic HII region is formed within which large amounts of molecular hydrogen form which will allow the gas to cool efficiently when gravity assembles it into larger dark matter halos. The filaments surrounding the first star hosting halo are largely shielded and provide the pathway for gas to stream into the halo when the star has died. We present the first fully three dimensional cosmological radiation hydrodynamical simulations that follow all these effects. A novel adaptive ray casting technique incorporates the time dependent radiative transfer around point sources. This approach is fast enough so that radiation transport, kinetic rate equations, and hydrodynamics are solved self-consistently. It ...

  11. Chemical distribution of HII regions towards the Galactic anticentre

    Fernández-Martín, Alba; Vílchez, José Manuel; Mampaso, Antonio


    We study the physical and chemical properties of a sample of HII regions located at RG >11 kpc and present the radial distribution of abundances towards the Galaxy anticentre. We carried out optical spectroscopic observations of nine HII regions with the WHT. The sample was increased by searching the literature for optical observations of regions towards the Galactic anticentre, re-analysing them to obtain a single sample of 23 objects covering the Galactocentric radius from 11 kpc to 18 kpc to be processed in a homogeneous and consistent manner. Accurate electron densities and temperatures of several ionic species were derived in 13 HII regions. These physical parameters were applied to the spectra to determine direct total chemical abundances. For those regions without direct estimations of temperature, chemical abundances were derived by performing tailor-made photoionisation models and/or by using an empirical relation obtained from radio recombination and optical temperatures. We performed weighted least...

  12. Time Variability in Simulated Ultracompact and Hypercompact HII Regions

    Galván-Madrid, Roberto; Keto, Eric; Mac Low, Mordecai-Mark; Banerjee, Robi; Klessen, Ralf S


    Ultracompact and hypercompact HII regions appear when a star with a mass larger than about 15 solar masses starts to ionize its own environment. Recent observations of time variability in these objects are one of the pieces of evidence that suggest that at least some of them harbor stars that are still accreting from an infalling neutral accretion flow that becomes ionized in its innermost part. We present an analysis of the properties of the HII regions formed in the 3D radiation-hydrodynamic simulations presented by Peters et al. (2010) as a function of time. Flickering of the HII regions is a natural outcome of this model. The radio-continuum fluxes of the simulated HII regions, as well as their flux and size variations are in agreement with the available observations. From the simulations, we estimate that a small but non-negligible fraction (~ 10 %) of observed HII regions should have detectable flux variations (larger than 10 %) on timescales of ~ 10 years, with positive variations being more likely to ...

  13. Re-analysis of the radio luminosity function of Galactic HII regions

    Paladini, R; Noriega-Crespo, A; Carey, S J


    We have re-analyzed continuum and recombination lines radio data available in the literature in order to derive the luminosity function (LF) of Galactic HII regions. The study is performed by considering the first and fourth Galactic quadrants independently. We estimate the completeness level of the sample in the fourth quadrant at 5 Jy, and the one in the first quadrant at 2 Jy. We show that the two samples (fourth or first quadrant) include, as well as giant and super-giant HII regions, a significant number of sub-giant sources. The LF is obtained, in each Galactic quadrant, with a generalized Schmidt's estimator using an effective volume derived from the observed spatial distribution of the considered HII regions. The re-analysis also takes advantage of recently published ancillary absorption data allowing to solve the distance ambiguity for several objects. A single power-law fit to the LFs retrieves a slope equal to -2.23+/-0.07 (fourth quadrant) and to -1.85+/-0.11 (first quadrant). We also find margina...

  14. HII regions feeding the interstellar medium in M83

    Blasco-Herrera, Javier; Beckman, John; Gutiérrez, Leonel; Lundgren, Andreas; Font, Joan; Hernandez, Olivier; Carignan, Claude


    We analyse the internal dynamics of star-forming HII regions and their efficiency in interacting with the ISM. We use GHaFaS (Fabry-Perot) data of the nearby spiral galaxy M83 to perform multiple-Gaussian fitting to the integrated Halpha emission line for 136 HII regions, advanced instrumental response subtraction and to study the Luminosity-velocity dispersion relation. We find that the best way of dealing with instrumental response effects is convolving its actual shape with the Gaussian before fitting and that in our data almost none of the regions need a secondary Gaussian.

  15. On the Form of the HII Region Luminosity Function

    Oey, M S


    Observed variations in the HII region luminosity function (HII LF) seen in spiral arm vs. interarm regions, and different galactic Hubble type, can be explained simply by evolutionary effects and maximum number of ionizing stars per cluster. We present Monte Carlo simulations of the HII LF, drawing the number of ionizing stars N_* from a power-law distribution of constant slope, and the stellar masses from a Salpeter IMF with an upper-mass limit of 100 M_sol. We investigate the evolution of the HII LF, as determined by stellar main-sequence lifetimes and ionizing luminosities, for a single burst case and continuous creation of the nebular population. Shallower HII LF slopes measured for the arms of spiral galaxies can be explained as a composite slope, expected for a zero-age burst population, whereas the interarm regions tend to be dominated by evolved rich clusters described by a single, steeper slope. Steeper slopes in earlier-type galaxies can be explained simply by a lower maximum N_* cutoff found for th...

  16. Nonlinear Dynamics of Ionization Fronts in HII Regions

    Mizuta, A; Kane, J O; Pound, M W; Remington, B A; Ryutov, D D; Takabe, H


    Hydrodynamic instability of an accelerating ionization front (IF) is investigated with 2D hydrodynamic simulations, including absorption of incident photoionizing photons, recombination in the HII region, and radiative molecular cooling. When the amplitude of the perturbation is large enough, nonlinear dynamics of the IF triggered by the separation of the IF from the cloud surface is observed. This causes the second harmonic of the imposed perturbation to appear on the cloud surfaces, whereas the perturbation in density of ablated gas in the HII region remains largely single mode. This mismatch of modes between the IF and the density perturbation in the HII region prevents the strong stabilization effect seen in the linear regime. Large growth of the perturbation caused by Rayleigh-Taylor-like instability is observed late in time.

  17. On the Size of HII Regions around High Redshift Quasars

    Maselli, A; Ferrara, A; Choudhury, T R


    We investigate the possibility of constraining the ionization state of the Intergalactic Medium (IGM) close to the end of reionization (z ~ 6) by measuring the size of the HII regions in high-z quasars spectra. We perform a combination of multiphase SPH and 3D radiative transfer (RT) simulations to reliably predict the properties of typical high-z quasar HII regions, embedded in a partly neutral IGM. From the analysis of mock spectra along lines of sight through the simulated QSO environment we find that the HII region size derived from quasar spectra is on average 30 % smaller than the physical one. Additional maximum likelihood analysis shows that this offset induces an overestimate of the neutral hydrogen fraction, x_HI, by a factor ~ 3. By applying the same statistical method to a sample of observed QSOs our study favors a mostly ionized (x_HI < 0.06) universe at z=6.1.

  18. Integral field spectroscopy of HII regions in M33

    López-Hernández, Jesús; Terlevich, Roberto; Rosa-González, Daniel; Díaz, Ángeles; Benito, Rubén García; Vílchez, José; Hägele, Guillermo


    Integral field spectroscopy (IFS) is presented for star forming regions in M33. A central area of 300 x 500 pc^2 and the external HII region IC 132, at a galactocentric distance {\\sim} 19arcmin (4.69 kpc) were observed with the Potsdam Multi Aperture Spectrophotometer (PMAS) instrument at the 3.5 m telescope of the Calar Alto Hispano- Alem\\'an observatory (CAHA). The spectral coverage goes from 3600 A to 1{\\mu}m to include from [OII]{\\lambda}3727 A to the near infrared lines required for deriving sulphur electron temperature and abundance diagnostics. Local conditions within individual HII regions are presented in the form of emission line fluxes and physical conditions for each spatial resolution element (spaxel) and for segments with similar H{\\alpha} surface brightness. A clear dichotomy is observed when comparing the central to outer disc HII regions. While the external HII region has higher electron temperature plus larger H{\\beta} equivalent width, size and excitation, the central region has higher exti...

  19. An Isolated HII Region near ESO 481-G017

    Santiago-Figueroa, N; Werk, J; Ryan-Weber, E; Meurer, G


    We obtained VLA 21-cm observations of the galaxy ESO 481-G017 to determine the environment and trigger of remote star formation traced by a HII region found 43 kpc from the galaxy (in projection). ESO 481-G017 is an early type spiral galaxy with a HI mass of 1.1*10^9 Msun and a distance of 55 Mpc. The isolated HII region has a H-alpha luminosity of 10^38.1 erg s^-1 and minimal continuum emission suggesting that new stars have formed where little or no stars previously existed. The difference in velocity between the HI disk of ESO 481-G017 (3840-4000 km s^-1) and the isolated HII region (4701 +/- 80 km s^-1) indicates the origin of the HII region may be stars forming in a tidal feature or newly triggered star formation in a very low luminosity companion galaxy. The VLA observations shed light on the nature of this young object.

  20. GMRT and VLA Observations at 49 cm and 20 cm of the HII Region near = 24.8°, = 0.1°

    N. G. Kantharia; W. M. Goss; D. Anish Roshi; Niruj R. Mohan; Francois Viallefond


    We report multi-frequency radio continuum and hydrogen radio recombination line observations of HII regions near = 24.8°, = 0.1° using the Giant Metrewave Radio Telescope(GMRT) at 1.28 GHz ( = 172), 0.61 GHz ( = 220) and the Very Large Array (VLA) at 1.42 GHz ( = 166). The region consists of a large number of resolved HII regions and a few compact HII regions as seen in our continuum maps, many of which have associated infrared (IR) point sources. The largest HII region at = 24.8° and = 0.1° is a few arcmins in size and has a shell-type morphology. It is a massive HII region enclosing ∼ 550 M⊙ with a linear size of 7 pc and an rms electron density of ∼ 110 cm-3 at a kinematic distance of 6 kpc. The required ionization can be provided by a single star of spectral type O5.5. We also report detection of hydrogen recombination lines from the HII region at = 24.8° and = 0.1° at all observed frequencies near = 100 km s-1. We model the observed integrated line flux density as arising in the diffuse HII region and find that the best fitting model has an electron density comparable to that derived from the continuum.We also report detection of hydrogen recombination lines from two other HII regions in the field.

  1. Rotation of the Warm Molecular Gas Surrounding Ultracompact HII Regions

    Klaassen, P D; Keto, E R; Zhang, Q


    We present molecular line and 1.4 mm continuum observations towards five massive star forming regions at arcsecond resolution using the Submillimeter Array (SMA). We find that the warm molecular gas surrounding each HII region (as traced by SO_2 and OCS) appears to be undergoing bulk rotation. From the molecular line emission and thermal component of the continuum emission, we independently derived gas masses for each region which are consistent with each other. From the free-free component of the continuum emission we estimate the minimum stellar mass required to power the HII region and find that this mass, when added to the derived gas mass, is a significant fraction of the dynamical mass for that region.

  2. Topology and Sizes of HII Regions during Cosmic Reionization

    Friedrich, Martina M; Alvarez, Marcelo A; Shapiro, Paul R; Iliev, Ilian T


    We use the results of large-scale simulations of reionization to explore methods for characterizing the topology and sizes of HII regions during reionization. We use four independent methods for characterizing the sizes of ionized regions. Three of them give us a full size distribution: the friends-of-friends (FOF) method, the spherical average method (SPA) and the power spectrum (PS) of the ionized fraction. These latter three methods are complementary: While the FOF method captures the size distribution of the small scale H~II regions, which contribute only a small amount to the total ionization fraction, the spherical average method provides a smoothed measure for the average size of the H~II regions constituting the main contribution to the ionized fraction, and the power spectrum does the same while retaining more details on the size distribution. Our fourth method for characterizing the sizes of the H II regions is the average size which results if we divide the total volume of the H II regions by their...

  3. Dust Properties in HII Regions in M33

    Relano, M; Lisenfeld, U; Verley, S; Hermelo, I; Boquien, M; Albrecht, M; Kramer, C; Braine, J; Perez-Montero, E; De Looze, I; Xilouris, M; Kovacs, A; Staguhn, J


    The conversion of the IR emission into star formation rate can be strongly dependent on the physical properties of the dust, which are affected by the environmental conditions where the dust is embedded. We study here the dust properties of a set of HII regions in the Local Group Galaxy M33 presenting different spatial configurations between the stars, gas and dust to understand the dust evolution under different environments. We model the SED of each region using the DustEM tool and obtain the mass relative to hydrogen for Very Small Grains (YVSG), Polycyclic Aromatic Hydrocarbons (YPAH) and Big Grains (YBG). The relative mass of the VSGs (YVSG/YTOT) is a factor of 1.7 higher for HII regions classified as filled and mixed than for regions presenting a shell structure. The enhancement of VSGs within NGC 604 and NGC 595 is correlated to expansive gas structures with velocities greater than 50 km/s. The gas-to-dust ratio derived for the HII regions in our sample exhibits two regimes related to the HI-H2 transit...

  4. Single Star HII Regions in nearby LEGUS Galaxies

    Kayitesi, Bridget; Lee, Janice C.; Thilker, David A.; LEGUS Team


    It is believed that O stars typically form in clustered environments, however past observations have shown that there are a few O stars in the field that are fairly far from clusters and have low space velocities. The goal of this project is to determine whether these O stars can be born in situ or whether they are runaways ejected from their parent clusters due to binary supernova explosions or other dynamic interactions. To do this, we select candidate hot stars and compute an isolation metric based on distance from other hot stars and clusters. We then deploy Zooniverse citizen scientists to classify the isolated sources and their associated nebulae. The detected presence of an HII region allows us to confirm a candidate as a true O star. We use the Zooniverse classification system to study the morphology of these HII regions and determine the runaway status of the O stars.

  5. Realistic Models for Filling Factors in HII Regions

    Spangler, Steven R.; Costa, Allison H.; Bergerud, Brandon M.; Beauchamp, Kara M.


    One of the parameters used to describe HII regions and other ionized parts of the interstellar medium is the filling factor, defined as the volume fraction of an HII region occupied by matter. The best observational evidence for the existence of a filling factor less than unity is a discrepancy between the electron density derived from density-sensitive line ratios and the root mean square density obtained from emission measure measurements. Following the early, influential study by Osterbrock and Flather (ApJ 129, 26, 1959), most investigations of HII regions envision these objects as a group of isolated cells of high gas density embedded in a vacuum. This picture is at serious odds with more direct measurements of other astrophysical plasmas like the solar wind, where the density follows a less extreme probability distribution function (pdf) such as an exponential or lognormal. We have carried out a set of simulations in which model HII regions are created with different density pdfs such as exponential and lognormal as well as the extreme case of two delta functions. We calculate the electron density as inferred from spectroscopic line ratios and emission measures for all lines of sight through the model nebulas. In the cases of exponential and lognormal pdfs, the spectroscopically derived densities are higher than those obtained by the emission measures by factors of 20 to 100 percent. These are considerably smaller than values often reported in the literature, which can be an order of magnitude or greater. We will discuss possible ways to reconcile realistic density pdfs such as measured in space and laboratory plasmas with the results from astronomical spectroscopic measurements. Finally, we point out that for the Orion Nebula, the density discrepancy is due to geometry, not filling factor (O'Dell, ARAA 39, 99, 2001).

  6. HII Region Metallicity Distribution in the Milky Way Disk

    Balser, Dana S; Bania, T M; Anderson, L D


    The distribution of metals in the Galaxy provides important information about galaxy formation and evolution. HII regions are the most luminous objects in the Milky Way at mid-infrared to radio wavelengths and can be seen across the entire Galactic disk. We used the NRAO Green Bank Telescope (GBT) to measure radio recombination line and continuum emission in 81 Galactic HII regions. We calculated LTE electron temperatures using these data. In thermal equilibrium metal abundances are expected to set the nebular electron temperature with high abundances producing low temperatures. Our HII region distribution covers a large range of Galactocentric radius (5 to 22 kpc) and samples the Galactic azimuth range 330 degree to 60 degree. Using our highest quality data (72 objects) we derived an O/H Galactocentric radial gradient of -0.0383 +/- 0.0074 dex/kpc. Combining these data with a similar survey made with the NRAO 140 Foot telescope we get a radial gradient of -0.0446 +/- 0.0049 dex/kpc for this larger sample of ...

  7. The Fine Structure Lines of Hydrogen in HII Regions

    Dennison, B; Minter, A H; Dennison, Brian; Minter, Anthony H.


    The 2s_{1/2} state of hydrogen is metastable and overpopulated in HII regions. In addition, the 2p states may be pumped by ambient Lyman-alpha radiation. Fine structure transitions between these states may be observable in HII regions at 1.1 GHz (2s_{1/2}-2p_{1/2}) and/or 9.9 GHz (2s_{1/2}-2p_{3/2}), although the details of absorption versus emission are determined by the relative populations of the 2s and 2p states. The n=2 level populations are solved with a parameterization that allows for Lyman-alpha pumping of the 2p states. The density of Lyman-alpha photons is set by their creation rate, easily determined from the recombination rate, and their removal rate. Here we suggest that the dominant removal mechanism of Lyman-alpha radiation in HII regions is absorption by dust. This circumvents the need to solve the Lyman-alpha transfer problem, and provides an upper limit to the rate at which the 2p states are populated by Lyman-alpha photons. In virtually all cases of interest, the 2p states are predominantl...

  8. Modeling the Photoionized Interface in Blister HII Regions

    Sankrit, R; Sankrit, Ravi


    We present a grid of photoionization models for the emission from photoevaporative interfaces between the ionized gas and molecular cloud in blister HII regions. For the density profiles of the emitting gas in the models, we use a general power law form calculated for photoionized, photoevaporative flows by Bertoldi (1989). We find that the spatial emission line profiles are dependent on the incident flux, the shape of the ionizing continuum and the elemental abundances. In particular, we find that the peak emissivity of the [SII] and [NII] lines are more sensitive to the elemental abundances than are the total line intensities. The diagnostics obtained from the grid of models can be used in conjunction with high spatial resolution data to infer the properties of ionized interfaces in blister HII regions. As an example, we consider a location at the tip of an ``elephant trunk'' structure in M16 (the Eagle Nebula) and show how narrow band HST-WFPC2 images constrain the HII region properties. We present a photo...

  9. New calibrations for abundance determinations in HII regions

    Pilyugin, L S


    Simple relations for deriving the oxygen abundance in HII regions with intensities of the three strong emission lines R_2, R_3, and N_2 (R calibration) or S_2, R_3, and N_2 (S calibration) in their spectra are suggested. A sample of 313 reference HII regions of the counterpart method is used as calibrating data points. Relations for the determination of nitrogen abundances, the R calibration, are also constructed. We find that the oxygen and nitrogen abundances in high-metallicity HII regions can be estimated using the intensities of the two strong lines R_2 and N_2 (or S_2 and N_2 for oxygen) only. The corresponding two-dimensional relations are provided. There are considerable advantages of the suggested calibration relations as compared to the existing ones. First, the oxygen and nitrogen abundances estimated through the suggested calibrations agree with the Te-based abundances within ~0.1 dex over the whole metallicity range, i.e., the relative accuracy of the calibration-based abundances is 0.1 dex. Alth...

  10. The Fragmenting Superbubble Associated with the HII Region W4

    West, J L; Normandeau, M; Landecker, T L; West, Jennifer L.; English, Jayanne; Normandeau, Magdalen


    New observations at high latitudes above the HII region W4 show that the structure formerly identified as a chimney candidate, an opening to the Galactic halo, is instead a superbubble in the process of fragmenting and possibly evolving into a chimney. Data at high Galactic latitudes (b > 5 degrees) above the W3/W4 star forming region at 1420 and 408 MHz Stokes I (total power) and 1420 MHz Stokes Q and U (linear polarization) reveal an egg-shaped structure with morphological correlations between our data and the H-alpha data of Dennison, Topasna, & Simonetti. Polarized intensity images show depolarization extending from W4 up the walls of the superbubble, providing strong evidence that the radio continuum is generated by thermal emission coincident with the H-alpha emission regions. We conclude that the parts of the HII region hitherto known as W4 and the newly revealed thermal emission are all ionized by the open cluster OCl 352. Assuming a distance of 2.35 kpc, the ovoid structure is 164 pc wide and ext...

  11. ATLASGAL --- properties of compact HII regions and their natal clumps

    Urquhart, J S; Moore, T J T; Purcell, C R; Hoare, M G; Schuller, F; Wyrowski, F; Csengeri, T; Menten, K M; Lumsden, S L; Kurtz, S; Walmsley, C M; Bronfman, L; Morgan, L K; Eden, D J; Russeil, D


    We present a complete sample of molecular clumps containing compact and ultra-compact (UC) HII regions between \\ell=10\\degr and 60\\degr\\ and $|b|<1\\degr, identified by combining the the ATLASGAL submm and CORNISH radio continuum surveys with visual examination of archival infrared data. Our sample is complete to optically thin, compact and UCHII regions driven by a zero age main sequence star of spectral type B0 or earlier embedded within a 1,000 Msun clump. In total we identify 213 compact and UCHII regions, associated with 170 clumps. Unambiguous kinematic distances are derived for these clumps and used to estimate their masses and physical sizes, as well as the Lyman continuum fluxes and sizes of their embedded HII regions. We find a clear lower envelope for the surface density of molecular clumps hosting massive star formation of 0.05 g cm^{-2}, which is consistent with a similar sample of clumps associated with 6.7 GHz masers. The mass of the most massive embedded stars is closely correlated with the ...

  12. The environs of the HII region Gum31

    Cappa, C; Amorin, R; Vasquez, J


    We analyze the distribution of the interstellar matter in the environs of the \\hii region Gum 31, excited by the open cluster NGC 3324, located in the complex Carina region, with the aim of investigating the action of the massive stars on the surrounding neutral material. We use 21cm-line data, radio continuum images at 0.843, 2.4 and 4.9 GHz, $^{12}${\\bf CO(1-0)} observations, and IRAS and MSX infrared data. Adopting a distance of 3 kpc for the \\hii\\ region and the ionizing cluster, we have derived an electron density of 33$\\pm$3 cm$^{-3}$ and an ionized mass of (3.3$\\pm$1.1)$\\times10^3$ M$_{\\odot}$ based on the radio continuum data at 4.9 GHz. The \\hi 21-cm line images revealed an \\hi shell surrounding the H {\\sc ii} region. The \\hi structure is 10.0$\\pm$1.7 pc in radius, has a neutral mass of 1500$\\pm$500 M$_{\\odot}$, and is expanding at 11 km s$^{-1}$. The associated molecular gas amounts to (1.5$\\pm$0.5)$\\times10^5$ M$_{\\odot}$, being its volume density of about 500 cm^{-3}. This molecular material proba...

  13. Anomalous Microwave Emission from the HII region RCW175

    Dickinson, C; Allison, J R; Bond, J R; Casassus, S; Cleary, K; Davis, R J; Jones, M E; Mason, B S; Myers, S T; Pearson, T J; Readhead, A C S; Sievers, J L; Taylor, A C; Todorovic, M; White, G J; Wilkinson, P N


    We present evidence for anomalous microwave emission in the RCW175 \\hii region. Motivated by 33 GHz $13\\arcmin$ resolution data from the Very Small Array (VSA), we observed RCW175 at 31 GHz with the Cosmic Background Imager (CBI) at a resolution of $4\\arcmin$. The region consists of two distinct components, G29.0-0.6 and G29.1-0.7, which are detected at high signal-to-noise ratio. The integrated flux density is $5.97\\pm0.30$ Jy at 31 GHz, in good agreement with the VSA. The 31 GHz flux density is $3.28\\pm0.38$ Jy ($8.6\\sigma$) above the expected value from optically thin free-free emission based on lower frequency radio data and thermal dust constrained by IRAS and WMAP data. Conventional emission mechanisms such as optically thick emission from ultracompact \\hii regions cannot easily account for this excess. We interpret the excess as evidence for electric dipole emission from small spinning dust grains, which does provide an adequate fit to the data.

  14. Effective temperature of ionizing stars of extragalactic HII regions

    Dors, O L; Cardaci, M V; Krabbe, A C


    The effective temperature (Teff) of the radiation field of the ionizing star(s) of a large sample of extragalactic HII regions was estimated using the R= log([OII](3727)/[OIII]5007) index. We used a grid of photoionization models to calibrate the Teff-R relation finding that it has a strong dependence with the ionizing parameter while it shows a weak direct dependence with the metallicity (variations in Z imply variations in U) of both the stellar atmosphere of the ionizing star and the gas phase of the HII region. Since the R index varies slightly with the Teff for values larger than 40 kK, the R index can be used to derive the Teff in 30-40 kK range. A large fraction of the ionization parameter variation is due to differences in the temperature of the ionizing stars and then the use of the (relatively) low Teff dependent S2=[S II](6717+31)/Ha emission-line ratio to derive the ionization parameter is preferable over others in the literature. We propose linear metallicity dependent relationships between S2 an...

  15. Photoionization models of the CALIFA HII regions. I. Hybrid models

    Morisset, C; Sánchez, S F; Galbany, L; Garcia-Benito, R; Husemann, B; Marino, R A; Mast, D; Roth, M M; Colaboration, CALIFA


    Photoionization models of HII regions require as input a description of the ionizing SED and of the gas distribution, in terms of ionization parameter U and chemical abundances (e.g. O/H and N/O). A strong degeneracy exists between the hardness of the SED and U, which in turn leads to high uncertainties in the determination of the other parameters, including abundances. One way to resolve the degeneracy is to fix one of the parameters using additional information. For each of the ~ 20000 sources of the CALIFA HII regions catalog, a grid of photoionization models is computed assuming the ionizing SED being described by the underlying stellar population obtained from spectral synthesis modeling. The ionizing SED is then defined as the sum of various stellar bursts of different ages and metallicities. This solves the degeneracy between the shape of the ionizing SED and U. The nebular metallicity (associated to O/H) is defined using the classical strong line method O3N2 (which gives to our models the status of "h...

  16. Forming a Primordial Star in a Relic HII Region

    O'Shea, B W; Whalen, D; Norman, M L; Shea, Brian W. O'; Abel, Tom; Whalen, Dan; Norman, Michael L.


    There has been considerable theoretical debate over whether photoionization and supernova feedback from the first Population III stars facilitate or suppress the formation of the next generation of stars. We present results from an Eulerian adaptive mesh refinement simulation demonstrating the formation of a primordial star within a region ionized by an earlier nearby star. Despite the higher temperatures of the ionized gas and its flow out of the dark matter potential wells, this second star formed within 23 million years of its neighbor's death. The enhanced electron fraction within the HII region catalyzes rapid molecular hydrogen formation that leads to faster cooling in the subsequent star forming halos than in the first halos. This ``second generation'' primordial protostar has a much lower accretion rate because, unlike the first protostar, it forms in a rotationally supported disk of approximately 10-100 solar masses. In contrast to unpreprocessed regions, such configurations may allow binaries or mul...

  17. Line Emission from Radiation-Pressurized HII Region II: Dynamics and Population Synthesis

    Verdolini, Silvia; Krumholz, Mark R; Matzner, Christopher D; Tielens, Alexander G G M


    Optical and infrared emission lines from HII regions are an important diagnostic used to study galaxies, but interpretation of these lines requires significant modeling of both the internal structure and dynamical evolution of the emitting regions. Most of the models in common use today assume that HII region dynamics are dominated by the expansion of stellar wind bubbles, and have neglected the contribution of radiation pressure to the dynamics, and in some cases also to the internal structure. However, recent observations of nearby galaxies suggest that neither assumption is justified, motivating us to revisit the question of how HII region line emission depends on the physics of winds and radiation pressure. In a companion paper we construct models of single HII regions including and excluding radiation pressure and winds, and in this paper we describe a population synthesis code that uses these models to simulate galactic collections of HII regions with varying physical parameters. We show that the choice...

  18. A Large Scale, Low Frequency Murchison Widefield Array Survey of Galactic HII regions between 260< l <\\340

    Hindson, L; Hurley-Walker, N; Callingham, J R; Su, H; Morgan, J; Bell, M; Bernardi, G; Bowman, J D; Briggs, F; Cappallo, R J; Deshpande, A A; Dwarakanath, K S; For, B -Q; Gaensler, B M; Greenhill, L J; Hancock, P; Hazelton, B J; Kapinska, A D; Kaplan, D L; Lenc, E; Lonsdale, C J; Mckinley, B; McWhirter, S R; Mitchell, D A; Morales, M F; Morgan, E; Oberoi, D; Offringa, A; Ord, S M; Procopio, P; Prabu, T; UdayaShankar, N; Srivani, K S; Staveley-Smith, L; Subrahmanyan, R; Tingay, S J; Wayth, R B; Webster, R L; Williams, A; Williams, C L; Wu, C; Zheng, Q


    We have compiled a catalogue of HII regions detected with the Murchison Widefield Array (MWA) between 72 and 231MHz. The multiple frequency bands provided by the MWA allow us identify the characteristic spectrum generated by the thermal Bremsstrahlung process in HII regions. We detect 306 HII regions between 260 < l < 340 and report on the positions, sizes, peak, integrated flux density, and spectral indices of these HII regions. By identifying the point at which HII regions transition from the optically thin to thick regime we derive the physical properties including the electron density, ionised gas mass and ionising photon flux, towards 61 HII regions. This catalogue of HII regions represents the most extensive and uniform low frequency survey of HII regions in the Galaxy to date.

  19. Spectral line survey of the ultracompact HII region Monoceros R2

    Ginard, D.; Gonzalez-Garcia, M.; Fuente, A.; Cernicharo, J.; Alonso-Albi, T.; Pilleri, P.; Gerin, M.; Garcia-Burillo, S.; Ossenkopf, V.; Rizzo, J. R.; Kramer, C.; Goicoechea, J. R.; Pety, J.; Berne, O.; Joblin, C.


    Context. Ultracompact (UC) HII regions constitute one of the earliest phases in the formation of a massive star and are characterized by extreme physical conditions (G(0) > 10(5) Habing field and n > 10(6) cm(-3)). The UC HII Mon R2 is the closest example and an excellent target to study the chemist

  20. Distinguishing between HII regions and planetary nebulae with Hi-GAL, WISE, MIPSGAL, and GLIMPSE

    Anderson, Loren D; Barlow, M J; Garcia-Lario, P; Noriega-Crespo, A


    HII regions and planetary nebulae (PNe) both emit at radio and infrared (IR) wavelengths, and angularly small HII regions can be mistaken for PNe. This problem of classification is most severe for HII regions in an early evolutionary stage, those that are extremely distant, or those that are both young and distant. Using data from the Herschel Hi-GAL survey, as well as WISE and the Spitzer MIPSGAL and GLIMPSE surveys, we wish to establish characteristic IR colors that can be used to distinguish between HII regions and PNe. We perform aperture photometry measurements for a sample of 126 HII regions and 43 PNe at wavelengths from 8.0 micron to 500 micron. We find that HII regions and PNe have distinct IR colors. The most robust discriminating color criteria are [F12/F8] 1.3, and [F160/F24] > 0.8 (or alternately [F160/F22] > 0.8), where the brackets indicate the log of the flux ratio. All three of these criteria are individually satisfied by over 98% of our sample of HII regions and by about 10% of our sample o...

  1. Evolution of Blister-Type HII Regions in a Magnetized Medium

    Gendelev, Leo


    We use the three-dimensional Athena ionizing radiation-magnetohydrodynamics (IRMHD) code to simulate blister-type HII regions driven by stars on the edge of magnetized gas clouds. We compare these to simulations of spherical HII regions where the star is embedded deep within a cloud, and to non-magnetized simulations of both types, in order to compare their ability to drive turbulence and influence star formation. We find that magnetized blister HII regions can be very efficient at injecting energy into clouds. This is partly a magnetic effect: the magnetic energy added to a cloud by an HII region is comparable to or larger than the kinetic energy, and magnetic fields can also help collimate the ejected gas, increasing its energy yield. As a result of these effects, a blister HII region expanding into a cloud with a magnetic field perpendicular to its edge injects twice as much energy by 5 Myr as a non-magnetized blister HII region driven by a star of the same luminosity. Blister HII regions are also more eff...

  2. Deuteration around the ultracompact HII region Mon R2

    Treviño-Morales, S P; Fuente, A; Kramer, C; Roueff, E; González-García, M; Cernicharo, J; Gerin, M; Goicoechea, J R; Pety, J; Berné, O; Ossenkopf, V; Ginard, D; García-Burillo, S; Rizzo, J R; Viti, S


    The massive star-forming region Mon R2 hosts the closest ultra-compact HII region that can be spatially resolved with current single-dish telescopes. We used the IRAM-30m telescope to carry out an unbiased spectral survey toward two important positions (namely IF and MP2), in order to studying the chemistry of deuterated molecules toward Mon R2. We found a rich chemistry of deuterated species at both positions, with detections of C2D, DCN, DNC, DCO+, D2CO, HDCO, NH2D, and N2D+ and their corresponding hydrogenated species and isotopologs. Our high spectral resolution observations allowed us to resolve three velocity components: the component at 10 km/s is detected at both positions and seems associated with the layer most exposed to the UV radiation from IRS 1; the component at 12 km/s is found toward the IF position and seems related to the molecular gas; finally, a component at 8.5 km/s is only detected toward the MP2 position, most likely related to a low-UV irradiated PDR. We derived the column density of ...

  3. Untangling the Recombination Line Emission from HII Regions with Multiple Velocity Components

    Anderson, L D; Wenger, T V; Bania, T M; Balser, Dana S


    HII regions are the ionized spheres surrounding high-mass stars. They are ideal targets for tracing Galactic structure because they are predominantly found in spiral arms and have high luminosities at infrared and radio wavelengths. In the Green Bank Telescope HII Region Discovery Survey (GBT HRDS) we found that >30% of first Galactic quadrant HII regions have multiple hydrogen radio recombination line (RRL) velocities, which makes determining their Galactic locations and physical properties impossible. Here we make additional GBT RRL observations to determine the discrete HII region velocity for all 117 multiple-velocity sources within 18deg. < l < 65deg. The multiple-velocity sources are concentrated in the zone 22deg. < l < 32deg., coinciding with the largest regions of massive star formation, which implies that the diffuse emission is caused by leaked ionizing photons. We combine our observations with analyses of the electron temperature, molecular gas, and carbon recombination lines to determ...

  4. Imaging HII Regions from Galaxies and Quasars During Reionisation with SKA

    Wyithe, Stuart; Kim, Hansik


    The ionisation structure of the Intergalactic Medium (IGM) during reionisation is sensitive to the unknown galaxy formation physics that prevailed at that time. This structure introduces non-Gaussian statistics into the redshifted 21 cm fluctuation amplitudes that can only be studied through tomographic imaging, which will clearly discriminate between different galaxy formation scenarios. Imaging the ionisation structure and cosmological HII regions during reionisation is therefore a key goal for the SKA. For example, the SKA1-LOW baseline design with a 1 km diameter core will resolve HII regions expected from galaxy formation models which include strong feedback on low-mass galaxy formation. Imaging the smaller HII regions that result from galaxy formation in the absence of SNe feedback will also be possible for SKA1-LOW in the later stages of reionisation, but may require the greater sensitivity of SKA early in the reionisation era. In addition to having baselines long enough to resolve the HII regions, the...

  5. The Discovery of Raman Scattering in HII Regions

    Dopita, Michael A; Sutherland, Ralph S; Kewley, Lisa J; Groves, Brent A


    We report here on the discovery of faint extended wings of H\\alpha\\ observed out to an apparent velocity of ~ 7600 km/s in the Orion Nebula (M42) and in five HII regions in the Large and the Small Magellanic Clouds. We show that, these wings are caused by Raman scattering of both the O I and Si II resonance lines and stellar continuum UV photons with H I followed by radiative decay to the H I n=2 level. The broad wings also seen in H\\beta\\ and in H\\gamma\\ result from Raman scattering of the UV continuum in the H I n=4 and n=5 levels respectively.The Raman scattering fluorescence is correlated with the intensity of the narrow permitted lines of O I and Si II. In the case of Si II, this is explained by radiative pumping of the same 1023.7\\AA\\ resonance line involved in the Raman scattering by the Ly\\beta\\ radiation field. The subsequent radiative cascade produces enhanced Si II 5978.9, 6347.1$ and 6371.4\\AA\\ permitted transitions. Finally we show that in O I, radiative pumping of the 1025.76\\AA\\ resonance line ...

  6. High-velocity gas associated ultracompact HII regions

    XU; Ye(徐烨); JIANG; Dongrong(蒋栋荣); YANG; Chuanyi(杨传义); ZHENG; Xingwu(郑兴武); GU; Minfeng(顾敏峰); PEI; Chunchuan(裴春传)


    We present the results of a survey for high-velocity 12CO (1-0) emission associated H2O masers and ultracompact (UC) HII regions. The aim is to investigate the relationship between H2O masers, CO high-velocity gas (HVG) and their associated infrared sources. Our sample satisfies Wood & Churchwell criterion. Almost 70 % of the sources have full widths (FWs) greater than 15 km@ s?1 at T*a = 100 mK and 15 % have FWs greater than 30 km@ s?1. In most of our objects there is excess high velocity emission in the beam. There is a clear correlation between CO line FWs and far-infrared luminosities: the FW increases with the FIR luminosity. The relation suggests that more luminous sources are likely to be more energetic and able to inject more energy into their surroundings. As a result, larger FW of the CO line could be produced. In most of our sources, the velocities of peak of the H2O emission are in agreement with those of the CO cloud, but a number of them have a large blueshift with respect to the CO peak. These masers might stem from the amplifications of a background source, which may amplify some unobservable weak masers to an observable level.

  7. A Protostellar Jet Emanating from a Hypercompact HII Region

    Guzmán, Andrés E; Rodríguez, Luis F; Contreras, Yanett; Dougados, Catherine; Cabrit, Sylvie


    We present radio continuum observations of the high-mass young stellar object (HMYSO) G345.4938+01.4677 made using the Australia Telescope Compact Array (ATCA) at 5, 9, 17, and 19 GHz. These observations provide definite evidence that the outer and inner pairs of radio lobes consist of shock ionized material being excited by an underlying collimated and fast protostellar jet emanating from a hypercompact HII region. By comparing with images taken 6 yr earlier at 5 and 9 GHz using the same telescope, we assess the proper motions of the radio sources. The outer West and East lobes exhibit proper motions of $64\\pm12$ and $48\\pm13$ milliarcsec yr$^{-1}$, indicating velocities projected in the plane of the sky and receding from G345.4938+01.4677 of $520$ and $390$ km s$^{-1}$, respectively. The internal radio lobes also display proper motion signals consistently receding from the HMYSO, with magnitudes of $17\\pm11$ and $35\\pm10$ milliarcsec yr$^{-1}$ for the inner West and East lobes, respectively. The morphology ...

  8. 7 mm continuum observations of ultra compact HII regions

    Leto, P.; Umana, G.; Trigilio, C.; Buemi, C. S.; Dolei, S.; Manzitto, P.; Cerrigone, L.; Siringo, C.


    Aims: Ultra compact HII (UCHII) regions are indicators of high-mass star formation sites and are distributed mainly in the Galactic plane. They exhibit a broad band spectrum with significant emission between near-IR and radio wavelengths. We intend to investigate the possible contribution of the forthcoming ESA Planck mission to the science of UCHII regions by evaluating the possibility of detecting UCHIIs that are bright in the radio regime. Methods: We performed new 7 mm observations of a sample of UCHII regions. The observations were designed to acquire high-frequency radio spectra. For each source in our sample, the free-free radio spectrum has been modeled. Along with far-IR measurements, our spectra allow us to estimate the flux densities of the sources in the millimeter and sub-millimeter bands. We extrapolated and summed the ionized-gas (free-free radio emission) and dust (thermal emission) contributions in the afore mentioned wavelength ranges. The possibility of Planck detecting the selected sources can be assessed by comparing the estimated flux densities to the expected sensitivity in each Planck channel. To obtain a realistic estimation of the noise produced by the Galactic emission, the Planck sky model software package was used. Results: For each target source, from our new 7 mm data and other radio measurements from the literature, important physical parameters such as electron density and their spatial distribution, source geometry and emission measure were derived. We conclude that, in the case of the present sample, located close to the Galactic center, Planck will have a very low detection rate. In contrast, assuming that our sample is representative of the whole UCHII-region population, we derive a very high probability of detecting this kind of source with Planck if located instead close to the anticenter. From the analysis of the ionized-gas properties, we suggest that the selected sample could also be contaminated by other kinds of Galactic

  9. The Green Bank Telescope HII Region Discovery Survey: III. Kinematic Distances

    Anderson, L D; Balser, Dana S; Rood, Robert T


    Using the HI Emission/Absorption method, we resolve the kinematic distance ambiguity and derive distances for 149 of 182 (82%) HII regions discovered by the Green Bank Telescope HII Region Discovery Survey (GBT HRDS). The HRDS is an X-band (9GHz, 3cm) GBT survey of 448 previously unknown HII regions in radio recombination line and radio continuum emission. Here we focus on HRDS sources from 67deg. > l > 18deg., where kinematic distances are more reliable. The 25 HRDS sources in this zone that have negative recombination line velocities are unambiguously beyond the orbit of the Sun, up to 20kpc distant. They are the most distant HII regions yet discovered. We find that 61% of HRDS sources are located at the far distance, 31% at the tangent point distance, and only 7% at the near distance. "Bubble" HII regions are not preferentially at the near distance (as was assumed previously) but average 10kpc from the Sun. The HRDS nebulae, when combined with a large sample of HII regions with previously known distances, ...


    R. E. Carlos Reyes


    Full Text Available Usamos datos en la región ultravioleta, visible e infrarroja de 11 regiones HII en las Nubes de Magallanes, a fin de determinar sus parámetros físicos y abundancias químicas. Así, hacemos un modelo de fotoionización de seis regiones HII en la Gran Nube de Magallanes (GNM y cinco regiones HII en la Pequeña Nube de Magallanes (PNM, lo cual nos permite calcular las abundancias de He, G, N, O, Ne, S y Ar. Los valores calculados se comparan con los encontrados en la literatura para regiones HII, nebulosas planetarias y estrellas. Obtuvimos los valores de las abundancias ajustando modelos del código CLOUDY para las intensidades de línea observadas. Además, las observaciones en el Observatorio Pico dos Dias de [S II] λ6717/λ6731 para regiones HII en la PNM nos permiten determinar la densidad electrónica. Los datos IUE de las líneas [C III] λ1909 se usan para determinar la abundancia de C de seis y cinco regiones HII en la GNM y en la PNM, respectivamente.

  11. Study of morphology and stellar content of the Galactic HII region IRAS 16148-5011

    Mallick, K K; Tamura, M; Linz, H; Samal, M R; Ghosh, S K


    An investigation of the IRAS 16148-5011 region - a cluster at a distance of 3.6 kpc - is presented here, carried out using multiwavelength data in near-infrared (NIR) from the 1.4m Infrared Survey Facility telescope, mid-infrared (MIR) from the archival Spitzer GLIMPSE survey, far-infrared (FIR) from the Herschel archive, and low-frequency radio continuum observations at 1280 and 843 MHz from the Giant Metrewave Radio Telescope (GMRT) and Molonglo Survey archive, respectively. A combination of NIR and MIR data is used to identify 7 Class I and 133 Class II sources in the region. Spectral Energy Distribution (SED) analysis of selected sources reveals a 9.6 Msolar, high-mass source embedded in nebulosity. However, Lyman continuum luminosity calculation using radio emission - which shows a compact HII, region - indicates the spectral type of the ionizing source to be earlier than B0-O9.5. Free-free emission SED modelling yields the electron density as 138 cm^{-3}, and thus the mass of the ionized hydrogen as ~16...

  12. A New Interpretation of the Bipolar HII Region S106 from HCN J = 3 - 2 Mapping Observations

    Sheng-Li Qin; Jun-Jie Wang; Gang Zhao; Martin Miller


    The first mapping observations of the bipolar HII region S106 in HCN J = 3-2 line were made by KOSMA submillimeter telescope in April, 2004. The results show that there is a bipolar cloud core is perpendicular to the IRS4 and that the flat structure of molecular cloud core is perpendicular to the axis of the outflow. This image roughly corresponds to the optical image where a dark lane bisects the bipolar HII region. Together with the optical, infrared and radio data, we conclude that the central UC HII region, and that a neutral disk is responsible for the bipolar HII region and the outflow.

  13. The Green Bank Telescope HII Region Discovery Survey II. The Source Catalog

    Anderson, L D; Balser, Dana S; Rood, Robert T


    The Green Bank Telescope HII Region Discovery Survey has doubled the number of known HII regions in the Galactic zone 343deg.\\leql\\leq67deg. with |b|\\leq1deg. We detected 603 discrete hydrogen radio recombination line (RRL) components at 9GHz (3cm) from 448 targets. Our targets were selected based on spatially coincident mid-infrared and 20cm radio continuum emission. Such sources are almost invariably HII regions; we detected hydrogen RRL emission from 95% of our target sample. The sensitivity of the Green Bank Telescope and the power of its spectrometer together made this survey possible. Here we provide a catalog of the measured properties of the RRL and continuum emission from the survey nebulae. The derived survey completeness limit, 180mJy at 9GHz, is sufficient to detect all HII regions ionized by single O-stars to a distance of 12kpc. These recently discovered nebulae share the same distribution on the sky as does the previously known census of Galactic HII regions. On average, however, the new nebula...

  14. Line Emission from Radiation-Pressurized HII Regions I: Internal Structure and Line Ratios

    Yeh, Sherry C C; Krumholz, Mark R; Matzner, Christopher D; Tielens, Alexander G G M


    The emission line ratios [OIII]5007/H-beta and [NII]6584/H-alpha have been adopted as an empirical way to distinguish between the fundamentally different mechanisms of ionization in emission-line galaxies. However, detailed interpretation of these diagnostics requires calculations of the internal structure of the emitting HII regions, and these calculations depend on the assumptions one makes about the relative importance of radiation pressure and stellar winds. In this paper we construct a grid of quasi-static HII region models to explore how choices about these parameters alter HII regions' emission line ratios. We find that, when radiation pressure is included in our models, HII regions reach a saturation point beyond which further increases in the luminosity of the driving stars does not produce any further increase in effective ionization parameter, and thus does not yield any further alteration in an HII region's line ratio. We also show that, if stellar winds are assumed to be strong, the maximum possi...

  15. 20-CM radio-continuum study of the SMC: Part III - Compact HII Regions

    Wong, G F; Crawford, E J; Tothill, N F H; De Horta, A Y; Galvin, T J


    We present and discuss a new catalogue of 52 compact HII regions in the Small Magellanic Cloud (SMC) and a newly created deep 1420 MHz (\\lambda=20 cm) radio-continuum image of the N19 region located in the southwestern part of the SMC. The new images were created by merging 1420 MHz radio-continuum archival data from the Australian Telescope Compact Array. The majority of these detected radio compact HII regions have rather flat spectral indices which indicates, as expected, that the dominant emission mechanism is of thermal nature.

  16. CHAOS I: Direct Chemical Abundances for HII Regions in NGC 628

    Berg, Danielle A; Skillman, Evan D; Pogge, Richard W; Moustakas, John; Groh-Johnson, Mara


    The CHemical Abundances of Spirals (CHAOS) project leverages the combined power of the Large Binocular Telescope (LBT) with the broad spectral range and sensitivity of the Multi Object Double Spectrograph (MODS) to measure "direct" abundances in large samples of HII regions in spiral galaxies. We present LBT MODS observations of 62 HII regions in the nearby NGC628. We measure one or more auroral lines ([OIII] 4363, [NII] 5755, [SIII] 6312, or [OII] 7320,7330) in a large number of HII regions (40). Comparing derived temperatures from multiple auroral line measurements, we find: a strong correlation between temperatures based on [SIII] and [NII]; and large discrepancies for some temperatures based on [OII] and [OIII]. These trends are consistent with other observations in the literature, yet, given the widespread use and acceptance of [OIII] as a temperature determinant, the magnitude of the T[OIII] discrepancies still came as a surprise. Based on these results, we conduct a uniform abundance analysis using the...

  17. Extraplanar HII regions in the edge-on spiral galaxies NGC 3628 and NGC 4522

    Stein, Y.; Bomans, D. J.; Ferguson, A. M. N.; Dettmar, R.-J.


    Context. Gas infall and outflow are critical for determining the star formation rate and chemical evolution of galaxies but direct measurements of gas flows are difficult to make. Young massive stars and Hii regions in the halos of galaxies are potential tracers for accretion and/or outflows of gas. Aims: Gas phase abundances of three Hii regions in the lower halos of the edge-on galaxies NGC 3628 and NGC 4522 are determined by analyzing optical long-slit spectra. The observed regions have projected distances to the midplane of their host from 1.4 to 3 kpc. Methods: With the measured flux densities of the optical nebular emission lines, we derived the oxygen abundance 12 + log(O/H) for the three extraplanar Hii regions. The analysis was based on one theoretical and two empirical strong-line calibration methods. Results: The resulting oxygen abundances of the extraplanar Hii regions are comparable to the disk Hii regions in one case and are a little lower in the other case. Since our results depend on the accuracy of the metallicity determinations, we critically discuss the difference of the calibration methods we applied and confirm previously noted offsets. From our measurements, we argue that these three extraplanar Hii regions were formed in the disk or at least from disk material. We discuss the processes that could transport disk material into the lower halo of these systems and conclude that gravitational interaction with a companion galaxy is most likely for NGC 3628 while ram pressure is favored in the case of NGC 4522. Based on observations gathered as part of observing program 64.N-0208(A), 3.6 m telescope with European Southern Observatory (ESO) Faint Object Spectrograph and Camera (EFOSC2) at ESO, La Silla observatory.

  18. X-ray observations of the Sagittarius D HII region toward the Galactic center with Suzaku

    Sawada, M.; Tsujimoto, M.; Koyama, K.; Law, C.J.; Tsuru, T.G.; Hyodo, Y.


    We present a Suzaku X-ray study of the Sagittarius D (Sgr D) HII region in the Galactic center region. Two 18' × 18' images by the X-ray Imaging Spectrometer (XIS) encompass the entire Sgr D complex. Thanks to the low background, XIS discovered two diffuse sources with low surface brightness and obt

  19. A Study of Molecular Cloud Associated with the HII Region Sh156

    Kang, Meejoo; Lee, Youngung


    We have conducted observations toward the molecular cloud associated with the HII region Sh 156 in tcocom (J=1-0), ȩocom(J=1-0), and CS(J=2-1) using the TRAO 14 m telescope. Combining with existing \\cocom(J=1-0) data of the Outer Galaxy Survey, we delineated the physical properties of the cloud. We found that there is a significant sign of interaction between the HII region and the molecular gas. We estimated the masses of the molecular cloud, using three different techniques; the most plausible mass is estimated to be 1.37 × 105 M⊙, using a conversion factor of X=1.9 × 1020 \\conf, and this is similar to virial mass estimate. This implies that the cloud is gravitationally bound and in virial equilibrium even though it is closely associated with the HII region. In addition to existing outflow, we found several MSX and IRAS point sources associated with dense core regions. Thus, more star forming activities other than the existing HII region are also going on in this region.

  20. Scaling Relations of Star-Forming Regions: from kpc-size clumps to HII regions

    Wisnioski, Emily; Blake, Chris; Poole, Gregory B; Green, Andrew W; Wyder, Ted; Martin, Chris


    We present the properties of 8 star-forming regions, or 'clumps,' in 3 galaxies at z~1.3 from the WiggleZ Dark Energy Survey, which are resolved with the OSIRIS integral field spectrograph. Within turbulent discs, \\sigma~90 km/s, clumps are measured with average sizes of 1.5 kpc and average Jeans masses of 4.2 x 10^9 \\Msolar, in total accounting for 20-30 per cent of the stellar mass of the discs. These findings lend observational support to models that predict larger clumps will form as a result of higher disc velocity dispersions driven-up by cosmological gas accretion. As a consequence of the changes in global environment, it may be predicted that star-forming regions at high redshift should not resemble star-forming regions locally. Yet despite the increased sizes and dispersions, clumps and HII regions are found to follow tight scaling relations over the range z=0-2 for size, velocity dispersion, luminosity, and mass when comparing >2000 HII regions locally and 30 clumps at z>1 (\\sigma \\propto r^{0.42+/-...

  1. The chemical composition of planetary nebulae and HII regions in NGC 3109

    Pena, Miriam; Richer, Michael


    We present deep spectrophotometry for a sample of 8 PNe and 12 HII regions in the irregular galaxy NGC 3109, to analyze the chemical composition of both types of nebulae. We present line intensities and the physical conditions and the abundances of He, O, Ne, N, S and Ar are derived, using the classical T_e-based method. We confirm our previous identification of PNe and HII regions based on photometry, except for one object that we argue is a compact HII region rather than a PN. We find that the chemical composition of the ISM in NGC 3109, as sampled by its HII regions, is remarkably uniform. The oxygen abundance is log O/H + 12 = 7.77 \\pm 0.07 in this galaxy, as compared to 8.05 \\pm 0.09 for the SMC. PNe show significantly higher oxygen abundances in NGC 3109: log O/H + 12 = 8.16 \\pm 0.19. We argue that, similarly to what has been suggested for some of the PNe in the Magellanic Clouds and other metal-poor galaxies, oxygen in the PNe in NGC 3109 is affected by dredge up in their progenitors. This could be als...




    It has recently become possible to reduce the raw IRAS Low Resolution Spectrograph (LRS) data in an interactive way. In this paper several problems concerning the LRS data of extended objects are addressed. We investigate the presence of the 21 mum emission feature in HII regions as reported by Cox

  3. The Pa{\\alpha} Luminosity Function of HII Regions in Nearby Galaxies from HST/NICMOS

    Liu, Guilin; Kennicutt, Robert C; Schinnerer, Eva; Sofue, Yoshiaki; Komugi, Shinya; Egusa, Fumi; Scoville, Nicholas Z


    The HII region luminosity function (LF) is an important tool for deriving the birthrates and mass distribution of OB associations, and is an excellent tracer of the newly formed massive stars and associations. To date, extensive work (predominantly in H{\\alpha}) has been done from the ground, which is hindered by dust extinction and the severe blending of adjacent (spatially or in projection) HII regions. Reliably measuring the properties of HII regions requires a linear resolution <40 pc, but analyses satisfying this requirement have been done only in a handful of galaxies, so far. As the first space-based work using a galaxy sample, we have selected 12 galaxies from our HST NICMOS Pa{\\alpha} survey and studied the luminosity function and size distribution of HII regions both in individual galaxies and cumulatively, using a virtually extinction-free tracer of the ionizing photon rate. The high angular resolution and low sensitivity to diffuse emission of NICMOS also offer an advantage over ground-based im...

  4. Dust dynamics and evolution in expanding HII regions. I. Radiative drift of neutral and charged grains

    Akimkin, V V; Pavlyuchenkov, Ya N; Wiebe, D S


    We consider dust drift under the influence of stellar radiation pressure during the pressure-driven expansion of an HII region using the chemo-dynamical model MARION. Dust size distribution is represented by four dust types: conventional polycyclic aromatic hydrocarbons (PAHs), very small grains (VSGs), big grains (BGs) and also intermediate-sized grains (ISGs), which are larger than VSGs and smaller than BGs. The dust is assumed to move at terminal velocity determined locally from the balance between the radiation pressure and gas drag. As Coulomb drag is an important contribution to the overall gas drag, we evaluate a grain charge evolution within the HII region for each dust type. BGs are effectively swept out of the HII region. The spatial distribution of ISGs within the HII region has a double peak structure, with a smaller inner peak and a higher outer peak. PAHs and VSGs are mostly coupled to the gas. The mean charge of PAHs is close to zero, so they can become neutral from time to time because of char...

  5. Hard X-rays from Ultra-Compact HII Regions in W49A

    Tsujimoto, M; Feigelson, E D; Getman, K V; Broos, P S


    We report the Chandra detection of hard X-ray emission from the Welch ring in W49A, an organized structure of ultra-compact (UC) HII regions containing a dozen nascent early-type stars. Two UC HII regions are associated with hard X-ray emission in a deep Advanced CCD Imaging Spectrometer image exposed for 96.7 ks. One of the two X-ray sources has no near-infrared counterpart and is extended by ~5 arcsec, or ~0.3 pc, at a distance of ~11.4 kpc, which is spatially aligned with the cometary radio continuum emission associated with the UC HII region. The X-ray spectrum of the emission, when fit with a thermal model, indicates a heavily absorbed plasma with extinction of \\~5x10^{23}/cm^{2}, temperature of ~7 keV, and X-ray luminosity in the 3.0-8.0 keV band of ~3x10^{33} ergs/s. Both the luminosity and the size of the emission resemble the extended hard emission found in UC HII regions in Sagittarius B2, yet they are smaller by an order of magnitude than the emission found in massive star clusters such as NGC 3603...

  6. Detecting stellar-wind bubbles through infrared arcs in HII regions

    Mackey, Jonathan; Gvaramadze, Vasilii V; Mohamed, Shazrene; Langer, Norbert; Harries, Tim J


    Mid-infrared arcs of dust emission are often seen near ionizing stars within HII regions. A possible explanations for these arcs is that they could show the outer edges of asymmetric stellar wind bubbles. We use two-dimensional, radiation-hydrodynamics simulations of wind bubbles within HII regions around individual stars to predict the infrared emission properties of the dust within the HII region. We assume that dust and gas are dynamically well-coupled and that dust properties (composition, size distribution) are the same in the HII region as outside it, and that the wind bubble contains no dust. We post-process the simulations to make synthetic intensity maps at infrared wavebands using the TORUS code. We find that the outer edge of a wind bubble emits brightly at 24um through starlight absorbed by dust grains and re-radiated thermally in the infrared. This produces a bright arc of emission for slowly moving stars that have asymmetric wind bubbles, even for cases where there is no bow shock or any corresp...

  7. The effect of Galactic foreground subtraction on redshifted 21-cm observations of quasar HII regions

    Geil, Paul M; Petrovic, Nada; Oh, Peng


    We assess the impact of Galactic synchrotron foreground removal on the observation of high-redshift quasar HII regions in redshifted 21-cm emission. We consider the case where a quasar is observed in an intergalactic medium (IGM) whose ionisation structure evolves slowly relative to the light crossing time of the HII region, as well as the case where the evolution is rapid. The latter case is expected towards the end of the reionisation era where the highest redshift luminous quasars will be observed. In the absence of foregrounds the fraction of neutral hydrogen in the IGM could be measured directly from the contrast between the HII region and surrounding IGM. However, we find that foreground removal lowers the observed contrast between the HII region and the IGM. This indicates that measurement of the neutral fraction would require modelling to correct for this systematic effect. On the other hand, foreground removal does not modify the most prominent features of the 21-cm maps. Using a simple algorithm we ...

  8. The metallicity gradient of M 33: chemical abundances of HII regions

    Magrini, L; Mampaso, A; Corradi, R L M; Leisy, P


    We present spectroscopic observations of a sample of 72 emission-line objects, including mainly HII regions, in the spiral galaxy M 33. Spectra were obtained with the multi-object, wide field spectrograph AF2/WYFFOS at the 4.2m WHT telescope. Line intensities, extinction, and electron density were determined for the whole sample of objects. The aim of the present work was to derive chemical and physical parameters of a set of HII regions, and from them the metallicity gradient. Electron temperatures and chemical abundances were derived for the 14 HII regions where both [OII] and [OIII] emission line fluxes were measured, including the electron temperature sensitive emission line [OIII] 436.3 nm and in a few cases [NII] 575.5 nm. The ionization correction factor (ICF) method was used to derive the total chemical abundances. The presence of abundance gradients was inferred from the radial behaviour of several emission-line ratios, and accurately measured from chemical abundances directly derived in 14 HII regio...

  9. Unveiling the birth and evolution of the HII region Sh2-173

    Cichowolski, S; Ortega, M E; Cappa, C E; Vasquez, J


    Based on a multiwavelength study, the ISM around the HII region Sh2-173 has been analyzed. The ionized region is clearly detected in the optical and in the radio continuum images. The analysis of the HI data shows a region of low emissivity that has an excellent morphological correlation with the radio continuum emission. The HII region is partially bordered by a photodissociation region, which, in turn, is encircled by a molecular structure. Taking into account the presence of noncircular motions in the Perseus spiral arm, together with previous distance estimates for the region, we adopt a distance of 2.5 +- 0.5 kpc for Sh2-173. Seven hot stars were identified in the field of Sh2-173, being only one an O-type star. The amount of energetic photons emitted by this star is enough to keep the region ionized and heat the dust. Given that an expanding HII region may trigger star formation, a search for YSO candidates was made using different infrared point source catalogues. A population of 46 YSO candidates was ...

  10. A multiwavelength study of star formation in the vicinity of Galactic HII region Sh2-100

    Samal, M. R.; Pandey, A. K.; Ojha, D. K.; Ghosh, S K; Kulkarni, V. K.; Kusakabe, N.; Tamura, M.; Bhatt, B. C.; Thompson, M A; Sagar, R


    We present multiwavelength investigation of morphology, physical-environment, stellar contents and star formation activity in the vicinity of star-forming region Sh 2-100. It is found that the Sh 2-100 region contains seven HII regions of ultracompact and compact nature. The present estimation of distance for three HII regions, along with the kinematic distance for others, suggests that all of them belong to the same molecular cloud complex. Using NIR photometry, we identified the most probab...

  11. A nebula in your computer: simulating the physics and chemistry of an HII region

    Bisbas, Thomas G


    In this contribution we discuss about numerical modeling of nebulae. In particular we emphasize on the dynamical evolution of an HII region and the chemical structure of a Photodissociation region. We do this using the Smoothed Particles Hydrodynamics code SEREN and the recently developed astrochemistry code 3D-PDR, respectively. We show an example application by simulating a cometary globule using these two codes.

  12. The Orion HII Region and the Orion Bar in the Mid-Infrared

    Salgado, F; Adams, J D; Herter, T L; Tielens, A G G M


    We present mid-infrared photometry of the Orion Bar obtained with FORCAST aboard SOFIA at 6.4, 6.6, 7.7, 19.7, 31.5 and 37.1 \\um. By complementing this observations with archival FORCAST and \\emph{Herschel}/PACS images we are able to construct a complete infrared spectral energy distribution of the Huygens region in the Orion nebula By comparing the infrared images with gas tracers, we find that PACS maps trace the molecular cloud, while the FORCAST data trace the photodissociation region (PDR) and HII region. Analysis of the energetics of the region reveal that the PDR extends for 0.28~pc along the line-of-sight and that the Bar is inclined at an angle of $4\\degr$. The infrared and submillimeter images reveal that the Orion Bar represents a swept up shell with a thickness of 0.1~pc. The mass of the shell implies a shock velocity of $\\simeq 3$ km/s and an age of $\\simeq 10^5$ yr for the HII region. Our analysis shows that the UV and infrared dust opacities in the HII region and the PDR are a factor 5 to 10 lo...

  13. Spitzer--IRAC Imagery and Photometry of Ultracompact HII Regions With Extended Emission

    De la Fuente-Acosta, E; Grave, J M C; Kumar, M S N; Trinidad, M A; Kurtz, S; Kemp, S; Franco, J; Quevedo, G


    We present the results of a morphological study performed to a sample of Ultracompact (UC) HII regions with Extended Emission (EE) using Spitzer--IRAC imagery and 3.6 cm VLA conf. D radio-continuum (RC) maps. Some examples of the comparison between maps and images are presented. Usually there is an IR point source counterpart to the peak(s) of RC emission, at the position of the UC source. We find that the predominant EE morphology is the cometary, and in most cases is coincident with IR emission at 8.0 $\\mu$m. Preliminary results of Spitzer--IRAC photometry of a sub-sample of 13 UC HII regions with EE based on GLIMPSE legacy data are also presented. Besides, individual IRAC photometry was performed to 19 UC sources within these 13 regions. We show that UC sources lie on specific locus, both in IRAC color-color and AM-product diagnostic diagrams. Counts of young stellar sources are presented for each region, and we conclude that a proportion of ~ 2%, ~10%, and ~88% of sources in the UC HII regions with EE are...

  14. From Ultracompact to Extended HII Regions. II: Cloud Gravity and Stellar Motion

    Franco, J; Kurtz, S; Franco, Jose; Garcia-Segura, Guillermo; Kurtz, Stan


    The dynamical evolution of HII regions with and without stellar motion in dense, structured molecular clouds is studied. Clouds are modeled in hydrostatic equilibrium, with gaussian central cores and external halos that obey r**-2 and r**-3 density power laws. The cloud gravity is included as a time-independent, external force. Stellar velocities of 0, 2, 8, and 12 km/s are considered. When stellar motion is included, stars move from the central core to the edge of the cloud, producing transitions from ultracompact to extended HII regions as the stars move into lower density regions. The opposite behavior occurs when stars move toward the cloud cores. The main conclusion of our study is that ultracompact HII regions are pressure-confined entities while they remain embedded within dense cores. The confinement comes from ram and/or ambient pressures. The survival of ultracompact regions depends on the position of the star with respect to the core, the stellar life-time, and the core crossing time. Stars with ve...

  15. Primordial 4He abundance: a determination based on the largest sample of HII regions with a methodology tested on model HII regions

    Izotov, Y I; Guseva, N G


    We verified the validity of the empirical method to derive the 4He abundance used in our previous papers by applying it to CLOUDY (v13.01) models. Using newly published HeI emissivities, for which we present convenient fits as well as the output CLOUDY case B hydrogen and HeI line intensities, we found that the empirical method is able to reproduce the input CLOUDY 4He abundance with an accuracy of better than 1%. The CLOUDY output data also allowed us to derive the non-recombination contribution to the intensities of the strongest Balmer hydrogen Halpha, Hbeta, Hgamma, and Hdelta emission lines and the ionisation correction factors for He. With these improvements we used our updated empirical method to derive the 4He abundances and to test corrections for several systematic effects in a sample of 1610 spectra of low-metallicity extragalactic HII regions, the largest sample used so far. From this sample we extracted a subsample of 111 HII regions with Hbeta equivalent width EW(Hbeta) > 150A, with excitation p...

  16. Revealing deuterium Balmer lines in HII regions with VLT-UVES

    Hébrard, G; Walsh, J R; Vidal-Madjar, A; Ferlet, R


    The search for deuterium Balmer lines with VLT-UVES is reported in HII regions of the Galaxy and the Magellanic Clouds. The DI lines appear as faint, narrow emission features in the blue wings of the HI Balmer lines and can be distinguished from high-velocity HI emission. The previous identification to deuterium is re-inforced beyond doubt. The detection of D-alpha and D-beta in Orion (Hebrard et al. 2000) is confirmed and deuterium lines are now detected up to at least D-eta. The UVES observations provide the first detection of Balmer DI lines in four new HII regions (M 8, M 16, M 20, and DEM S 103 in SMC), demonstrating that these lines are of common occurence.

  17. Sh2-205: Three independent HII regions or only one?

    Romero, G. A.; Cappa, C. E.

    Resumen: We present a study of the HII region Sh2-205 and its environs, based on data obtained from the CGPS, 12CO observations and MSX. We find that Sh2-205 can be separated in three independent optical structures: SH149.25-0.0, SH148.83-0.67, and LBN148.11-0.45. The derived spectral indices show the thermal nature of SH148.83-0.67 and LBN148.11-0.45. The morphology of SH148.83-0.67, both in optical and in radio, along with the energetic requirements indicate that this feature is an interstellar bubble powered by the UV photons of HD24431 (O9 III). LBN148.11-0.45 has the morphology of a classical HII region and their ionizing sources remain uncertain. Dust and molecular gas are found related to LBN148.11-0.45. Particularly, a photodissociation region is detected surrounding the central part of this HII region at infrared wavelengths.

  18. An Analysis of IRAS Identified Hii Regions and their Radio Properties

    Hughes, V A


    To try and confirm the types of object in the list of 2298 potential HII regions identified by Hughes \\& MacLeod from the IRAS Point Source Catalog, we selected a sample of 82 for observing at the VLA. We selected half with values of Y = log(F$_{25}$/F$_{12}$) $\\geq$ 0.8, and for control purposes, half with values of 0.3 $\\leq$ log(F$_{25}$/F$_{12}$) $\\leq$ 0.5. 78 radio sources were detected, and of all the objects, 72\\% had at least one associated radio source. Most of the radio sources had diameters of $<$ 3\\arcsec, which was the limit to the angular resolving power of the survey. Those with larger values of Y had significantly larger values of peak radio, integrated radio, and 100$\\mu$m flux densities than those with smaller Y. Also, they generally had associated masers, and thus were most likely young compact HII regions containing star forming regions. Those with smaller Y tended not to have associated maser activity and are probably older HII regions, or stars with high IR and ionizing radiation...

  19. Study of young stellar groupings in HII regions based on the spectral and photometric data

    Gusev, A S; Piskunov, A E; Kharchenko, N V; Pilyugin, L S; Ezhkova, O V; Khramtsova, M S; Guslyakova, S A; Bruevich, V V; Dodonov, S N; Lang, V; Shimanovskaya, E V; Efremov, Yu N


    We studied 102 star forming regions in seven spiral galaxies (NGC 628, NGC 783, NGC 2336, NGC 6217, NGC 6946, NGC 7331, and NGC 7678) on the basis of complex spectroscopic, photometric (UBVRI) and spectrophotometric (H alpha line) observations. Using data on the chemical composition and absorption in HII regions, obtained from spectroscopic observations, and using evolutionary models, we estimated physical parameters (ages and masses) of young stellar groupings embedded in HII regions. We found that the gas extinction, A(gas), which determined from the Balmer decrement, does not correspond in some cases to the absorption A(stars) in the young stellar associations (complexes). This is due to the spatial offset relative HII cloud the stellar group related to him. It has been found that the condition A(gas) = A(stars) does not satisfied for the star forming regions, in which: 1) the contribution to the total emission of gas in the B and/or V bands is higher than 40%, and 2) EW(H alpha) > 1500A. Extinction A(V) i...

  20. The impact of new ionizing fluxes on ISO observations of HII regions and starbursts

    Schärer, D; Schaerer, Daniel; Stasinska, Grazyna


    Extensive grids of photoionization models have been calculated for single star HII regions and evolving starbursts. We illustrate the predictions for IR fine structure lines which are used to analyse the stellar content, and derive properties such as the age and IMF. The impact of recent ionizing fluxes on the IR lines are shown. First comparisons of our starburst models with IR-diagnostics and the ISO observations of Genzel et al. (1998) are also presented.

  1. Chemical behavior of the Dwarf Irregular Galaxy NGC 6822. Its PN and HII region abundances

    Hernandez-Martinez, Liliana; Carigi, Leticia; Garcia-Rojas, Jorge


    We aim to derive the chemical behavior of a significant sample of PNe and HII regions in the irregular galaxy NGC 6822 The selected objects are distributed in different zones of the galaxy. Due to the faintness of PNe and HII regions in NGC 6822, to gather spectroscopic data with large telescopes is necessary. We obtained a well suited sample of spectra by employing VLT-FORS 2 and Gemini-GMOS spectrographs. Ionic and total abundances are calculated for the objects where electron temperatures can be determined through the detection of [OIII] \\lambda 4363 or/and [NII] \\lambda 5755 lines. A "simple" chemical evolution model has been developed and the observed data are used to compute a model for NGC 6822 in order to infer a preliminary chemical history in this galaxy. Confident determinations of He, O, N, Ne, S and Ar abundances were derived for a sample of 11 PNe and one HII region. We confirm that the present ISM is chemically homogeneous, at least in the central 2 kpc of the galaxy, showing a value 12+log O/H...

  2. A multiwavelength investigation of the HII region S311: Young stellar population and star formation

    Yadav, Ram Kesh; Sharma, Saurabh; Ojha, D K; Samal, M R; Mallick, K K; Jose, J; Ogura, K; Richichi, Andrea; Irawati, Puji; Kobayashi, N; Eswaraiah, C


    We present a multiwavelength investigation of the young stellar population and star formation activities around the \\hii region Sharpless 311. Using our deep near-infrared observations and archival {\\it Spitzer}-IRAC observations, we have detected a total of 125 young stellar objects (YSOs) in an area of $\\sim$86 arcmin$^2$. The YSOs sample include 8 Class I and 117 Class II candidate YSOs. The mass completeness of the identified YSOs sample is estimated to be 1.0 \\msun. The ages and masses of the majority of the candidate YSOs are estimated to be in the range of $\\sim$0.1$-$5 Myr and $\\sim$0.3$-$6 \\msun, respectively. The 8 \\mum image of S311 displays an approximately spherical cavity around the ionizing source which is possibly created due to the expansion of the \\hii region. The spatial distribution of the candidate YSOs reveals that a significant number of them are distributed systematically along the 8 $\\mu$m emission with a majority clustered around the eastern border of the \\hii region. Four clumps/com...

  3. Spitzer and Herschel multiwavelength characterization of the dust content of evolved HII regions

    Paladini, R; Veneziani, M; Noriega-Crespo, A; Anderson, L D; Piacentini, F; Goncalves, D Pinheiro; Paradis, D; Tibbs, C T; Bernard, J -P; Natoli, P


    We have analyzed a uniform sample of 16 evolved HII regions located in a 2 deg X 2 deg Galactic field centered at (l,b) = (30 deg, 0 deg) and observed as part of the Herschel Hi-GAL survey. The evolutionary stage of these HII regions was established using ancillary radio continuum data. By combining Hi-GAL PACS (70 micron, 160 micron) and SPIRE (250 micron, 350 micron and 500 micron) measurements with MIPSGAL 24 micron data, we built Spectral Energy Distributions (SEDs) of the sources and showed that a 2-component grey-body model is a good representation of the data. In particular, wavelengths > 70 micron appear to trace a cold dust component, for which we estimated an equilibrium temperature of the Big Grains (BGs) in the range 20 - 30 K, while for lambda < 70 micron, the data indicated the presence of a warm dust component at temperatures of the order of 50 - 90 K. This analysis also revealed that dust is present in the interior of HII regions, although likely not in a large amount. In addition, the data...

  4. PAH 8μm Emission as a Diagnostic of HII Region Optical Depth

    Oey, M. S.; Lopez-Hernandez, J.; Kellar, J. A.; Pellegrini, E. W.; Gordon, Karl D.; Jameson, Katherine; Li, Aigen; Madden, Suzanne C.; Meixner, Margaret; Roman-Duval, Julia; Bot, Caroline; Rubio, Monica; Tielens, A. G. G. M.


    PAHs are easily destroyed by Lyman continuum radiation and so in optically thick Stromgren spheres, they tend to be found only on the periphery of HII regions, rather than in the central volume. We therefore expect that in HII regions that are optically thin to ionizing radiation, PAHs would be destroyed beyond the primary nebular structure. Using data from the Spitzer SAGE survey of the Magellanic Clouds, we test whether 8 μm emission can serve as a diagnostic of optical depth in HII regions. We find that 8 μm emission does provide valuable constraints in the Large Magellanic Cloud, where objects identified as optically thick by their atomic ionization structure have 6 times higher median 8 μm surface brightness than optically thin objects. However, in the Small Magellanic Cloud, this differentiation is not observed. This appears to be caused by extremely low PAH production in this low-metallicity environment, such that any differentiation between optically thick and thin objects is washed out by stochastic variations, likely driven by the interplay between dust production and UV destruction. Thus, PAH emission is sensitive to nebular optical depth only at higher metallicities.

  5. Identification and multi-filter photometry of HII regions from nearby galaxies with J-PLUS

    Logroño-García, R.; Vilella-Rojo, G.; López-Sanjuan, C.; Varela, J.; Muniesa, D.; Lamadrid, J. L.; Cenarro, A. J.; J-PLUS, T.


    The Javalambre Photometric Local Universe Survey (J-PLUS) has already started the data acquisition phase at the Observatorio Astrofísico de Javalambre (OAJ) in Teruel, Spain. Benefiting from the large field of view (2 deg^2) and the 12 filters set of the T80Cam at the T80/JAST telescope, we aim to study the properties of HII regions in nearby galaxies (z J-PLUS bands using as reference the Hα+NII detection image. (5) Constructs the photo-spectra for each identified HII region. We demonstrate the capabilities of this method by comparing synthetic aperture photometry from SDSS spectra with the Hα flux measured with J-PLUS data. Such comparison can be found in the poster by Vilella-Rojo et al. Once the pipeline is implemented, we will generate a catalog of nearby HII regions at zJ-PLUS. With this catalog, we will study the impact of environment in the 2D star formation properties of nearby galaxies, taking advantage of the unprecedented large contiguous area that J-PLUS will offer.

  6. The HII region G35.673-00.847: another case of triggered star formation?

    Paron, S; Ortega, M E


    As part of a systematic study that we are performing with the aim to increase the observational evidence of triggered star formation in the surroundings of HII regions, we analyze the ISM around the HII region G35.673-00.847, a poorly studied source. Using data from large-scale surveys: Two Micron All Sky Survey, Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE), MIPSGAL, Galactic Ring Survey (GRS), VLA Galactic Plane Survey (VGPS), and NRAO VLA Sky Survey (NVSS) we performed a multiwavelength study of G35.673-00.847 and its surroundings. The mid IR emission, shows that G35.673-00.847 has an almost semi-ring like shape with a cut towards the galactic west. The radius of this semi-ring is about 1.5' (~1.6 pc, at the distance of ~3.7 kpc). The distance was estimated from an HI absorption study and from the analysis of the molecular gas. Indeed, we find a molecular shell composed by several clumps distributed around the HII region, suggesting that its expansion is collecting the surrounding mate...

  7. Enrichment of the ISM by metal-rich droplets and the abundance bias in HII regions

    Stasinska, Grazyna; Rodriguez, Monica; Henney, William J


    We critically examine a scenario for the enrichment of the interstellar medium (ISM) in which supernova ejecta follow a long (10^8 yr) journey before falling back onto the galactic disk in the form of metal-rich ``droplets'', These droplets do not become fully mixed with the interstellar medium until they become photoionized in HII regions. We investigate the hypothesis that the photoionization of these highly metallic droplets can explain the observed ``abundance discrepancy factors'' (ADFs), which are found when comparing abundances derived from recombination lines and from collisionally excited lines, both in Galactic and extragalactic HII regions. We derive bounds of 10^{13}--10^{15} cm on the droplet sizes inside HII regions in order that (1) they should not have already been detected by direct imaging of nearby nebulae, and (2) they should not be too swiftly destroyed by diffusion in the ionized gas. From photoionization modelling we find that, if this inhomogeneous enrichment scenario holds, then the r...

  8. Type II supernovae as probes of environment metallicity: observations of host HII regions

    Anderson, J P; Dessart, L; Hamuy, M; Galbany, L; Morrell, N I; Stritzinger, M D; Phillips, M M; Folatelli, G; Boffin, H M J; de Jaeger, T; Kuncarayakti, H; Prieto, J L


    Spectral modelling of SNII atmospheres indicates a clear dependence of metal line strengths on progenitor metallicity. This motivates further work to evaluate the accuracy with which these SNe can be used as metallicity indicators. To assess this accuracy we present a sample of SNII HII-region spectroscopy, from which environment abundances are derived. These environment abundances are compared to the observed strength of metal lines in SN spectra. Combining our sample with measurements from the literature, we present oxygen abundances of 119 host HII regions, by extracting emission line fluxes and using abundance diagnostics. Then, following Dessart et al., these abundances are compared to equivalent widths of Fe 5018 A at various time and colour epochs. Our distribution of inferred SNII host HII-region abundances has a range of ~0.6 dex. We confirm the dearth of SNeII exploding at metallicities lower than those found (on average) in the Large Magellanic Cloud. The equivalent width of Fe 5018 A at 50 days po...

  9. The population of planetary nebulae and HII regions in M81. A study of radial metallicity gradients and chemical evolution

    Stanghellini, Letizia; Villaver, Eva; Galli, Daniele


    We analyze the chemical abundances of planetary nebulae and HII regions in the M81 disk for insight on galactic evolution, and compare it with that of other galaxies, including the Milky Way. We acquired Hectospec/MMT spectra of 39 PNe and 20 HII regions, with 33 spectra viable for temperature and abundance analysis. Our PN observations represent the first PN spectra in M81 ever published, while several HII region spectra have been published before, although without a direct electron temperature determination. We determine elemental abundances of helium, nitrogen, oxygen, neon, sulfur, and argon in PNe and HII regions, and determine their averages and radial gradients. The average O/H ratio of PNe compared to that of the HII regions indicates a general oxygen enrichment in M81 in the last ~10 Gyr. The PN metallicity gradient in the disk of M81 is -0.055+-0.02 dex/kpc. Neon and sulfur in PNe have a radial distribution similar to that of oxygen, with similar gradient slopes. If we combine our HII sample with th...

  10. A radio continuum and infrared study of Galactic HII regions

    Martin-Hernandez, NL; van der Hulst, JM; Tielens, AGGM


    We present observations of the 4.8 and 8.6 GHz continuum emission towards 11 southern H II regions made with the Australian Telescope Compact Array. The observed objects were selected from the Infrared Space Observatory (ISO) spectral catalogue of compact H II regions (Peeters et al. 2002b). The mor

  11. The Spitzer Survey of the Small Magellanic Cloud: Discovery of Embedded Protostars in the HII Region NGC 346

    Simon, Joshua D; Whitney, Barbara A; Robitaille, Thomas P; Shah, Ronak Y; Makovoz, David; Stanimirovic, Snezana; Barba, Rodolfo H; Rubio, Monica


    We use Spitzer Space Telescope observations from the Spitzer Survey of the Small Magellanic Cloud (S3MC) to study the young stellar content of N66, the largest and brightest HII region in the SMC. In addition to large numbers of normal stars, we detect a significant population of bright, red infrared sources that we identify as likely to be young stellar objects (YSOs). We use spectral energy distribution (SED) fits to classify objects as ordinary (main sequence or red giant) stars, asymptotic giant branch stars, background galaxies, and YSOs. This represents the first large-scale attempt at blind source classification based on Spitzer SEDs in another galaxy. We firmly identify at least 61 YSOs, with another 50 probable YSOs; only one embedded protostar in the SMC was reported in the literature prior to the S3MC. We present color selection criteria that can be used to identify a relatively clean sample of YSOs with IRAC photometry. Our fitted SEDs indicate that the infrared-bright YSOs in N66 have stellar mas...

  12. Hydrodynamic Instability of Ionization Fronts in HII Regions

    Mizuta, A; Kane, J; Ryutov, D; Remington, B; Takabe, H; Pound, M


    The authors investigate hydrodynamic instability of accelerating ionization fronts with two dimensional hydrodynamic simulations. When recombination in the ionized region is turned off, Rayleigh-Taylor instability is effective. Perturbation grows up with classical Rayleigh-Taylor growth rate. In the case with recombination, the local difference of absorption profile works to smooth the surface. The perturbation does not grow and the amplitude follows a damped oscillations with time.

  13. Hii regions in ngc 5055. ii. physical properties

    M. Rozas


    Full Text Available En este artículo usamos las observaciones presentadas en Rozas (2007 de la galaxia NGC 5055 en las líneas Hα y Hβ, junto con observaciones CCD con filtros estrechos en las líneas [OII], [OIII], [SII] y S[III] para calcular las anchuras equivalentes, excitación, grados de ionización, parámetros de ionización y metalicidades de las regiones catalogadas en Rozas (2007.

  14. The Molecular Cloud Associated with the HII Region RCW:34

    Pagani, L.; Heydari-Malayeri, M.; Castets, A.


    We present millimetric multi-line observations of the molecular cloud associated with the H II region RCW 34. We believe we are able to present a coherent description of the cloud: a molecular bar on top of the H II region is divided into three elements: a dense, heated part situated in the post-shock trail, a cold, less dense part besides, left unperturbed and a diffuse component either in front of the dense parts or possibly mixed with them if the dense parts are clumpy. This diffuse component has a density of a few hundreds per cm-3, a temperature in the range 30-60 K and its opacity in 12CO is close to or less than unity. We show that this diffuse component, the existence of which is controversial, is the best explanation to the large 12CO (J: 1 → 0)/(J: 2 → 1) ratio we have observed. A simple-minded model is presented to approach its properties. The cloud is on top and partly in front of the H II region and can explain the 4.2 mag of visual extinction measured by one of us (Heydari-Malayeri 1988). The very high velocity flow detected in Hα by Heydari-Malayeri has no counterpart in radio but could be a direct visualisation of the so-called "Champagne effect" (Tonorio-Tagle 1979).

  15. HII Region Ionization of the Interstellar Medium: A Case Study of NGC 7538

    Luisi, Matteo; Balser, Dana S; Bania, T M; Wenger, Trey V


    Using data from the Green Bank Telescope, we analyze the radio continuum (free-free) and radio recombination line (RRL) emission of the compact HII region NGC 7538 (Sharpless 158). We detect extended radio continuum and hydrogen RRL emission beyond the photodissociation region (PDR) toward the north and east, but a sharp decrease in emission toward the south and west. This indicates that a non-uniform PDR morphology is affecting the amount of radiation "leaking" through the PDR. The strongest carbon RRL emission is found in the western PDR that appears to be dense. We compute a leaking fraction $f_R = 15 \\pm 5$ % of the radio continuum emission measured in the plane of the sky which represents a lower limit when accounting for the three-dimensional geometry of the region. We detect an average $^4\\textrm{He}^+/\\textrm{H}^+$ abundance ratio by number of $0.088 \\pm 0.003$ inside the HII region and a decrease in this ratio with increasing distance from the region beyond the PDR. Using Herschel Space Observatory d...

  16. VizieR Online Data Catalog: SN II in host HII regions (Anderson+, 2016)

    Anderson, J. P.; Gutierrez, C. P.; Dessart, L.; Hamuy, M.; Galbany, L.; Morrell, N. I.; Stritzinger, M. D.; Phillips, M. M.; Folatelli, G.; Boffin, H. M. J.; de Jaeger, T.; Kuncarayakti, H.; Prieto, J. L.


    The data analysed in this publication comprise two distinct types of observations. The first is of SN II optical spectroscopy obtained during their photospheric phases, i.e. from discovery to at most ~100 days post explosion. These data are used to extract absorption line pEW measurements. The second data set is emission line spectral observations of host HII regions of SNe II. These are used to estimate SN II environment oxygen abundances, which can be used as metallicity proxies. In the course of this work we compare our observational results with the predictions from the spectral models of Dessart et al. (2014MNRAS.440.1856D). (2 data files).

  17. New radio observations of anomalous microwave emission in the HII region RCW175

    Battistelli, E S; Cruciani, A; de Bernardis, P; Genova-Santos, R; Masi, S; Naldi, A; Paladini, R; Piacentini, F; Tibbs, C T; Verstraete, L; Ysard, N


    We have observed the HII region RCW175 with the 64m Parkes telescope at 8.4GHz and 13.5GHz in total intensity, and at 21.5GHz in both total intensity and polarization. High angular resolution, high sensitivity, and polarization capability enable us to perform a detailed study of the different constituents of the HII region. For the first time, we resolve three distinct regions at microwave frequencies, two of which are part of the same annular diffuse structure. Our observations enable us to confirm the presence of anomalous microwave emission (AME) from RCW175. Fitting the integrated flux density across the entire region with the currently available spinning dust models, using physically motivated assumptions, indicates the presence of at least two spinning dust components: a warm component with a relatively large hydrogen number density n_H=26.3/cm^3 and a cold component with a hydrogen number density of n_H=150/cm^3. The present study is an example highlighting the potential of using high angular-resolutio...

  18. Spectral line survey of the ultracompact HII region Mon R2

    Ginard, D; Fuente, A; Cernicharo, J; Alonso-Albi, T; Pilleri, P; Gerin, M; García-Burillo, S; Ossenkopf, V; Rizzo, J R; Kramer, C; Goicoechea, J R; Pety, J; Berné, O; Joblin, C


    Ultracompact (UC) HII regions constitute one of the earliest phases in the formation of a massive star and are characterized by extreme physical conditions (Go>10^5 Habing field and n>10^6 cm^-3). The UC HII Mon R2 is the closest one and therefore an excellent target to study the chemistry in these complex regions. We carried out a 3mm and 1mm spectral survey using the IRAM 30-m telescope towards three positions that represent different physical environments in Mon R2: (i) the ionization front (IF) at (0",0"); two peaks in the molecular cloud (ii) MP1 at the offset (+15",-15") and (iii) MP2 at the farther offset (0",40"). In addition, we carried out extensive modeling to explain the chemical differences between the three observed regions. We detected more than thirty different species. We detected SO+ and C4H suggesting that UV radiation plays an important role in the molecular chemistry of this region. We detected the typical PDR molecules CN, HCN, HCO, C2H, and c-C3H2. While the IF and the MP1 have a chemis...

  19. Constraining the escape fraction of ionizing photons from HII regions within NGC 300: A concept paper

    Niederhofer, Florian; Bastian, Nate; Ercolano, Barbara


    Using broadband photometry from the Hubble Space Telescope in combination with Very Large Telescope narrowband Halpha observations of the nearby spiral galaxy NGC 300, we explore a method for estimating the escape fractions of hydrogen-ionizing photons from HII regions within this galaxy. Our goal in this concept study is to evaluate the spectral types of the most massive stars using the broadband data and estimating their ionizing photon output with the help of stellar atmosphere models. A comparison with the Halpha flux that gives the amount of ionized gas in the HII region provides a measure of the escape fraction of ionizing photons from that region. We performed some tests with a number of synthetic young clusters with varying parameters to assess the reliability of the method. However, we found that the derived stellar spectral types and consequently the expected ionizing photon luminosity of a region is highly uncertain. The tests also show that on one hand we tended to overestimate the integrated phot...

  20. Interaction Between HII Region and AFGL333-Ridge: Implications to the Star Formation Scenario

    Nakano, Makoto; Chibueze, James O; Nagayama, Takumi; Omodaka, Toshihiro; Handa, Toshihiro; Sunada, Kazuyuki; Kamezaki, Tatsuya; Burns, Ross A


    We investigated the star formation activities in the AFGL333 region, which is in the vicinity of the W4 expanding bubble, by conducting NH3 (1,1), (2,2), and (3,3) mapping observations with the 45 m Nobeyama Radio Telescope at an angular resolution of 75". The morphology of the NH3 (1,1) map shows a bow-shape structure with the size of 2.0 x 0.6 pc as seen in the dust continuum. At the interface between the W4 bubble and the dense NH3 cloud, the compact HII region G134.2+0.8, associated with IRAS02245+6115, is located. Interestingly, just north and south of G134.2+0.8 we found NH3 emission exhibiting large velocity widths of ~ 2.8 km/s, compared to 1.8 km/s at the other positions. As the possibility of mechanical energy injection through the activity of YSO(s) is low, we considered the origin of the large turbulent gas motion as indication of interaction between the compact HII region and the periphery of the dense molecular cloud. We also found expanding motion of the CO emission associated with G134.2+0.8. ...

  1. A single HII region model of the strong interstellar scattering towards Sgr A*

    Sicheneder, Egid; Dexter, Jason


    Until recently, the strong interstellar scattering observed towards the Galactic center (GC) black hole, Sgr A*, was thought to come from dense gas within the GC region. The pulse broadening towards the transient magnetar SGR J1745-2900 near Sgr A* has shown that the source of the scattering is instead located much closer to Earth, possibly in a nearby spiral arm. We show that a single HII region along the line of sight, 1.5 - 4.8 kpc away from Earth with density ne of a few ˜eq 100 cm^{-3} and radius R ≃ 1.8 - 3.2 pc can explain the observed angular broadening of Sgr A*. Clouds closer to the GC overproduce the observed DM, providing an independent location constraint that agrees with that from the magnetar pulse broadening. Our model predicts that sources within ≲ 10 pc should show the same scattering origin as the magnetar and Sgr A*, while the nearest known pulsars with separations >20 pc should not. The radio spectrum of Sgr A* should show a cutoff from free-free absorption at 0.2 ≲ ν ≲ 1 GHz. For a magnetic field strength B ˜eq 15 - 70 {μ}G, the HII region could produce the rotation measure of the magnetar, the largest of any known pulsar, without requiring the gas near Sgr A* to be strongly magnetised.

  2. S7 : Probing the physics of Seyfert Galaxies through their ENLR & HII Regions

    Dopita, Michael A; Scharwachter, Julia; Kewley, Lisa J; Davies, Rebecca; Sutherland, Ralph; Kharb, Preeti; Jose, Jessy; Bhatt, Harish; Ramya, S; Hampton, Elise; Jin, Chichuan; Banfield, Julie; Zaw, Ingyin; Srivastava, Shweta; James, Bethan


    Here we present the first results from the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) which aims to investigate the physics of ~140 radio-detected southern active Galaxies with z<0.02 through Integral Field Spectroscopy using the Wide Field Spectrograph (WiFeS). This instrument provides data cubes of the central 38 x 25 arc sec. of the target galaxies in the waveband 340-710nm with the unusually high resolution of R=7000 in the red (530-710nm), and R=3000 in the blue (340-560nm). These data provide the morphology, kinematics and the excitation structure of the extended narrow-line region, probe relationships with the black hole characteristics and the host galaxy, measures host galaxy abundance gradients and the determination of nuclear abundances from the HII regions. From photoionisation modelling, we may determine the shape of the ionising spectrum of the AGN, discover whether AGN metallicities differ from nuclear abundances determined from HII regions, and probe grain destruction...

  3. Properties of compact HII regions and their host clumps in the inner vs outer Galaxy - early results from SASSy

    Djordjevic, Julie; Thompson, Mark; Urquhart, James S.


    We present a catalog of compact and ultracompact HII regions for all Galactocentric radii. Previous catalogs focus on the inner Galaxy (Rgal ≤ 8 kpc) but the recent SASSy 870 µm survey allows us to identify regions out to ~20 kpc. Early samples are also filled with false classifications leading to uncertainty when deriving star formation efficiencies in Galactic models. These objects have similar mid-IR colours to HII regions. Urquhart et al. (2013) found that they could use mid-IR, submm, and radio data to identify the genuine compact HII regions, avoiding confusion. They used this method on a small portion of the Galaxy (10 < l < 60), identifying 213 HII regions embedded in 170 clumps. We use ATLASGAL and SASSy, crossmatched with RMS, to sample the remaining galactic longitudes out to Rgal = 20 kpc. We derive the properties of the identified compact HII regions and their host clumps while addressing the implications for recent massive star formation in the outer Galaxy. Observations towards nearby galaxies are biased towards massive stars, affecting simulations and overestimating models for galactic evolution and star formation rates. The Milky Way provides the ideal template for studying factors affecting massive star formation rates and efficiencies at high resolution, thus fine-tuning those models. We find that there is no significant change in the rate of massive star formation in the outer vs inner Galaxy. Despite some peaks in known complexes and possible correlation with spiral arms, the outer Galaxy appears to produce massive stars as efficiently as the inner regions. However, many of the potential star forming SASSy clumps have no available radio counterpart to confirm the presence of an HII region or other star formation tracer. Follow-up observations will be required to verify this conclusion and are currently in progress.

  4. New 20-cm radio-continuum study of the small Magellanic cloud - part III: Compact Hii regions

    Wong G.F.


    Full Text Available We present and discuss a new catalogue of 48 compact Hii regions in the Small Magellanic Cloud (SMC and a newly created deep 1420 MHz (λ=20 cm radio-continuum image of the N19 region located in the southwestern part of the SMC. The new images were created by merging 1420 MHz radiocontinuum archival data from the Australian Telescope Compact Array. The majority of these detected radio compact Hii regions have rather flat spectral indices which indicates, as expected, that the dominant emission mechanism is of thermal nature.

  5. Detection of reactive ions in the ultracompact HII regions Mon R2 and G29.96-0.02

    Rizzo, J R; Rodríguez-Franco, A; García-Burillo, S


    We report the first detection of the reactive ions CO+ and HOC+ towards ultracompact (UC) HII regions, particularly in Mon R2 and G29.96-0.02. We have observed two positions in Mon R2, namely the peak of the UC HII region and a position in the high density molecular cloud which bounds it. CO+ and HOC+ were detected at the UC HII region but not at the molecular cloud, as expected if the CO$^+$ and HOC$^+$ emissions arise in the PDR surrounding the \\uch. The measured CO$^+$ and HOC$^+$ column densities are of the order of 10$^{11}$ cm$^{-2}$ in both sources, which yields a strikingly low [HCO$^+$]/[HOC$^+$] abundance ratio of 460 in Mon R2. These values are similar to those found in some other well-known PDRs, like NGC 7023 and the Orion Bar. We briefly discuss the chemical implications of these results.

  6. A multi-wavelength investigation of RCW175: an HII region harboring spinning dust emission

    Tibbs, C T; Compiegne, M; Dickinson, C; Alves, M I R; Flagey, N; Shenoy, S; Noriega-Crespo, A; Carey, S; Casassus, S; Davies, R D; Davis, R J


    Using infrared, radio continuum and spectral observations, we performed a detailed investigation of the HII region RCW175. We determined that RCW175, which actually consists of two separate HII regions, G29.1-0.7 and G29.0-0.6, is located at a distance of 3.2+/-0.2 kpc. Based on the observations we infer that the more compact G29.0-0.6 is less evolved than G29.1-0.7 and was possibly produced as a result of the expansion of G29.1-0.7 into the surrounding interstellar medium. We compute a star formation rate for RCW175 of (12.6+/-1.9)x10^{-5} M_{\\sun}/yr, and identified 6 possible young stellar object candidates within its vicinity. Additionally, we estimate that RCW175 contains a total dust mass of 215+/-53 M_{\\sun}. RCW175 has previously been identified as a source of anomalous microwave emission (AME), an excess of emission at cm wavelengths often attributed to electric dipole radiation from the smallest dust grains. We find that the AME previously detected in RCW175 is not correlated with the smallest dust ...

  7. StarBench: The D-type expansion of an HII region

    Bisbas, T G; Williams, R J R; Mackey, J; Tremblin, P; Raga, A C; Arthur, S J; Baczynski, C; Dale, J E; Frostholm, T; Geen, S; Haugboelle, T; Hubber, D; Iliev, I T; Kuiper, R; Rosdahl, J; Sullivan, D; Walch, S; Wuensch, R


    StarBench is a project focused on benchmarking and validating different star-formation and stellar feedback codes. In this first StarBench paper we perform a comparison study of the D-type expansion of an HII region. The aim of this work is to understand the differences observed between the twelve participating numerical codes against the various analytical expressions examining the D-type phase of HII region expansion. To do this, we propose two well-defined tests which are tackled by 1D and 3D grid- and SPH- based codes. The first test examines the `early phase' D-type scenario during which the mechanical pressure driving the expansion is significantly larger than the thermal pressure of the neutral medium. The second test examines the `late phase' D-type scenario during which the system relaxes to pressure equilibrium with the external medium. Although they are mutually in excellent agreement, all twelve participating codes follow a modified expansion law that deviates significantly from the classical Spit...

  8. On the Origin of the HII Regions Associated with Massive and Compact Superstar Clusters

    Silich, Sergiy; Tenorio-Tagle, Guillermo; Muñoz-Tuñón, Casiana

    This contribution to the IV Korea-Mexico meeting deals with the hydrodynamics of the matter reinserted within super star clusters (SSCs) by both stellar winds and supernova explosions, results recently printed in The Astrophysical Journal (Silich et al. 2007). The motivation of such a project arose from the persistent presence of the small mass and compact HII regions that sit right on top of many massive and compact SSCs, from which one expects a large mechanical energy power. The data used for our calculations appear only recently (see Smith et al. 2006) for the massive and compact SSC M82-A1. We presented in our paper the calculated flow, derived through analytical and semi-analytical methods, which led to almost identical results. We have found out that the only way of accommodating a compact HII region (4.5 pc in radius, in the case of M82-A1) on top of a 6.3 Myr old and massive (> 10^6 M_{⊙}) SSC with a half light radius of 3 pc, requires of two assumptions: a very low heating efficiency (Tagle et al. 2007) and a high pressure in the surrounding medium.

  9. The Role of Stellar Feedback in the Dynamics of HII Regions

    Lopez, Laura A; Bolatto, Alberto D; Prochaska, J Xavier; Ramirez-Ruiz, Enrico; Castro, Daniel


    Stellar feedback is often cited as the biggest uncertainty in galaxy formation models today. This uncertainty stems from a dearth of observational constraints as well as the great dynamic range between the small scales (1 kpc) that are shaped by this feedback. To bridge this divide, in this paper we aim to assess observationally the role of stellar feedback at the intermediate scales of HII regions. In particular, we employ multiwavelength data to examine several stellar feedback mechanisms in a sample of 32 HII regions in the Large and Small Magellanic Clouds (LMC and SMC, respectively). Using optical, infrared, radio, and X-ray images, we measure the pressures exerted on the shells from the direct stellar radiation, the dust-processed radiation, the warm ionized gas, and the hot X-ray emitting gas. We find that the warm ionized gas dominates over the other terms in all of the sources, although two have comparable dust-processed radiation pressures to their warm gas pressures. The hot gas pressures are compa...


    A. C. Raga


    Full Text Available Estudiamos las soluciones de una versión modificada de la ecuación de Lane-Emden isotérmica, la cual incorpora el efecto de la presión de radiación (dirigida hacia afuera asociada a las fotoionizaciones. Estas soluciones son relevantes para regiones HII alrededor de un cúmulo con ≈500 estrellas O, que puede fotoionizar el gas hasta distancias de ≈ pc (siendo n0 la densidad central del gas, donde son importantes los efectos tanto de la autogravedad como de la presión de radiación. Encontramos que las soluciones tienen una transición de un régimen "dominado por gravedad" (en el que las soluciones convergen a radios grandes a la solución de la esfera isotérmica autogravitante no singular a uno "dominado por presión de radiación" (en el que la densidad diverge a un radio finito para regiones HII con densidades centrales mayores que ncrit = 100 cm -3. Argumentamos que las soluciones con densidades centrales altas, dominadas por presión de radiación, no ocurrirán en muchas de las situaciones astrofísicamente relevantes, dada la ausencia de un posible medio confinador de presión suficientemente alta.

  11. Fossil HII Regions: Self-Limiting Star Formation at High Redshift

    Oh, S P; Haiman, Zoltan


    Recent results by the WMAP satellite suggest that the intergalactic medium was significantly reionized at redshifts as high as z~17. At this early epoch, the first ionizing sources likely appeared in the shallow potential wells of mini-halos with virial temperatures T < 10^4 K. Once such an ionizing source turns off, its surrounding HII region Compton cools and recombines. Nonetheless, we show that the ``fossil'' HII regions left behind remain at high adiabats, prohibiting gas accretion and cooling in subsequent generations of mini-halos. Thus, early star formation is self-limiting. We quantify this effect to show that star formation in mini-halos cannot account for the bulk of the electron scattering opacity measured by WMAP, which must be due to more massive objects. We argue that gas entropy, rather than IGM metallicity, regulates the evolution of the global ionizing emissivity, and impedes full reionization until lower redshifts. We discuss several important consequences of this early entropy floor for...

  12. Resolving the electron temperature discrepancies in HII Regions and Planetary Nebulae: kappa-distributed electrons

    Nicholls, David C; Sutherland, Ralph S


    The measurement of electron temperatures and metallicities in H ii regions and Planetary Nebulae (PNe) has-for several decades-presented a problem: results obtained using different techniques disagree. What it worse, they disagree consistently. There have been numerous attempts to explain these discrepancies, but none has provided a satisfactory solution to the problem. In this paper, we explore the possibility that electrons in H ii regions and PNe depart from a Maxwell-Boltzmann equilibrium energy distribution. We adopt a "kappa-distribution" for the electron energies. Such distributions are widely found in Solar System plasmas, where they can be directly measured. This simple assumption is able to explain the temperature and metallicity discrepancies in H ii regions and PNe arising from the different measurement techniques. We find that the energy distribution does not need to depart dramatically from an equilibrium distribution. From an examination of data from Hii regions and PNe it appears that kappa ~ ...

  13. The Genesis of Super Star Clusters as Self-Gravitating HII Regions

    Tan, J C; Tan, Jonathan C.; Kee, Christopher F. Mc


    We examine the effects of ionization, radiation pressure and main sequence winds from massive stars on self-gravitating, clumpy molecular clouds, thereby modeling the formation and pre-supernova feedback of massive star clusters. We find the process of ``turbulent mass loading'' is effective in confining HII regions. Extrapolating typical Galactic high-mass star forming regions to greater initial gas cloud masses and assuming steady star formation rates, we determine the timescales for cloud disruption. We find that a dense n_c ~ 2 x 10^5 cm^-3 cloud with initial mass M_c ~ 4 x 10^5 M_sun is able to form ~2 x 10^5 M_sun of stars (50% efficiency) before feedback disperses the gas after ~3 Myr. This mass and age are typical of young, optically visible super star clusters (SSCs). The high efficiency permits the creation of a bound stellar system.

  14. Comparative internal kinematics of the HII regions in interacting and isolated galaxies: implications for massive star formation modes

    Zaragoza-Cardiel, Javier; Font, Joan; García-Lorenzo, Begoña; Camps-Fariña, Artemi; Fathi, Kambiz; James, Philip A; Erroz-Ferrer, Santiago; Barrera-Ballesteros, Jorge; Cisternas, Mauricio


    We have observed 10 interacting galaxy pairs using the Fabry-Perot interferometer GH$\\alpha$FaS (Galaxy H$\\alpha$ Fabry-Perot system) on the $4.2\\rm{m}$ William Herschel Telescope (WHT) at the Observatorio del Roque de los Muchachos, La Palma. We present here the H$\\alpha$ surface brightness, velocity and velocity dispersion maps for the 10 systems we have not previously observed using this technique, as well as the physical properties (sizes, H$\\alpha$ luminosities and velocity dispersion) of 1259 HII regions from the full sample. We also derive the physical properties of 1054 HII regions in a sample of 28 isolated galaxies observed with the same instrument in order to compare the two populations of HII regions. We find a population of the brightest HII regions for which the scaling relations, for example the relation between the H$\\alpha$ luminosity and the radius, are clearly distinct from the relations for the regions of lower luminosity. The regions in this bright population are more frequent in the inte...

  15. Extinction and PAH intensity variations across the HII region IRAS 12063-6259

    Stock, D.; Peeters, E.; Tielens, X.; Otaguro, J.; Bik, A.

    The spatial variations in polycyclic aromatic hydrocarbon (PAH) band intensities are generally attributed to variations of the physical conditions in the environment hosting the emitting PAH molecules. However, in recent years, it has been suggested that such variations are caused mainly by extinction. To resolve this question, we have obtained near-infrared (NIR), mid-infrared (MIR) and radio observations of the compact HII region IRAS 12063-6259. We use these data to construct multiple independent extinction maps and to measure the main PAH feature intensities (6.2, 7.7, 8.6 and 11.2 µ m). Three extinction maps are derived: the first using the NIR hydrogen lines and case B recombination theory; the second combining the NIR data, radio data and case B recombination; and the third making use of the Spitzer/IRS MIR observations to measure the 9.8 µ m silicate absorption feature intensity using the Spoon method and PAHFIT. We conclude that different areas of IRAS 12063-6259 possess markedly different extinction properties, with some regions displaying both silicate absorption and corresponding NIR extinction, and other regions displaying NIR extinction and no corresponding silicate absorption. While such breakdowns of the relationship between the NIR extinction and the silicate absorption strength have been observed in molecular clouds, they have never been observed for HII regions. We then compare the PAH intensity variations in the Spitzer/IRS data after dereddening to those found in the original data. Generally it was found that the PAH band intensity variations persist even after dereddening, implying that extinction is not the main cause of the PAH band intensity variations.

  16. Spitzer Analysis of HII Region Complexes in the Magellanic Clouds: Determining a Suitable Monochromatic Obscured Star Formation Indicator

    Lawton, Brandon; Babler, Brian; Block, Miwa; Bolatto, Alberto D; Bracker, Steve; Carlson, Lynn R; Engelbracht, Charles W; Hora, Joseph L; Indebetouw, Remy; Madden, Suzanne C; Meade, Marilyn; Meixner, Margaret; Misselt, Karl; Oey, M S; Oliveira, Joana M; Robitaille, Thomas; Sewilo, Marta; Shiao, Bernie; Vijh, Uma P; Whitney, Barbara


    HII regions are the birth places of stars, and as such they provide the best measure of current star formation rates (SFRs) in galaxies. The close proximity of the Magellanic Clouds allows us to probe the nature of these star forming regions at small spatial scales. We aim to determine the monochromatic IR band that most accurately traces the bolometric IR flux (TIR), which can then be used to estimate an obscured SFR. We present the spatial analysis, via aperture/annulus photometry, of 16 LMC and 16 SMC HII region complexes using the Spitzer IRAC and MIPS bands. UV rocket data and SHASSA H-alpha data are also included. We find that nearly all of the LMC and SMC HII region SEDs peak around 70um, from ~10 to ~400 pc from the central sources. As a result, the sizes of HII regions as probed by 70um is approximately equal to the sizes as probed by TIR (about 70 pc in radius); the radial profile of the 70um flux, normalized by TIR, is constant at all radii (70um ~ 0.45 TIR); the 1-sigma standard deviation of the 7...

  17. The Elephant Trunk Nebula and the Trumpler 37 cluster: Contribution of triggered star formation to the total population of an HII region

    Getman, Konstantin V; Sicilia-Aguilar, Aurora; Broos, Patrick S; Kuhn, Michael A; Garmire, Gordon P


    Rich young stellar clusters produce HII regions whose expansion into the nearby molecular cloud is thought to trigger the formation of new stars. However, the importance of this mode of star formation is uncertain. This investigation seeks to quantify triggered star formation (TSF) in IC 1396A (a.k.a., the Elephant Trunk Nebula), a bright rimmed cloud (BRC) on the periphery of the nearby giant HII region IC 1396 produced by the Trumpler 37 cluster. X-ray selection of young stars from Chandra X-ray Observatory data is combined with existing optical and infrared surveys to give a more complete census of the TSF population. Over 250 young stars in and around IC 1396A are identified; this doubles the previously known population. A spatio-temporal gradient of stars from the IC 1396A cloud toward the primary ionizing star HD 206267 is found. We argue that the TSF mechanism in IC 1396A is the radiation-driven implosion process persisting over several million years. Analysis of the X-ray luminosity and initial mass f...

  18. Amplification of Magnetic Fields in a Primordial HII Region and Supernova

    Koh, Daegene


    Magnetic fields permeate the Universe on all scales and play a key role during star formation. We study the evolution of magnetic fields around a massive metal-free (Population III) star at $z \\sim 15$ during the growth of its HII region and subsequent supernova explosion by conducting three cosmological magnetohydrodynamic simulations with radiation transport. Given the theoretical uncertainty and weak observational constraints of magnetic fields in the early universe, we initialize the simulations with identical initial conditions only varying the seed field strength. We find that magnetic fields grow as $\\rho^{2/3}$ during the gravitational collapse preceding star formation, as expected from ideal spherical collapse models. Massive Population III stars can expel a majority of the gas from the host halo through radiative feedback, and we find that the magnetic fields are not amplified above the spherical collapse scaling relation during this phase. However, afterwards when its supernova remnant can radiativ...


    A. Luna


    Full Text Available Estamos sometiendo a pruebas un método para determinar las distancias para una muestra de regiones HII ultracompactas con colores en IRAS y con detección de CS(J=2-1. La ambigüedad de las distancias cinem aticas se resuelve mediante simulaciones Monte Carlo. Utilizando nubes moleculares sintéticas simulamos las distribuciones longitud heliocéntrica-radio (l-R sobre el plano galáctico, y las proyecciones asociadas longitudvelocidad LSR (l-VLSR. Se escoge la mejor distribución galáctica por comparación con los mapas observados de CO. Se presentan resultados preliminares para el IV cuadrante galáctico.

  20. Extragalactic Ultracompact HII Regions: Probing the Birth Environments of Super Star Clusters

    Johnson, K E


    In recent years, a number of extragalactic massive star clusters that are still deeply embedded in their birth material have been discovered. These objects represent the youngest stage of massive star cluster evolution yet observed, and the most massive and dense of these may be proto globular clusters. Their properties appear to be similar to those of ultracompact HII regions in the Galaxy, but scaled up in total mass and luminosity. In many cases, these clusters are only visible at mid-IR to radio wavelengths, and they have typically been detected as ``inverted'' spectrum radio sources. However, the set of existing observations is anemic, and our current physical model for these natal clusters in simplistic. This article will overview what we think we know about these objects based on existing observations and outline some of the most significant gaps in our current understanding.

  1. Formation of Population III Stars in Fossil HII Regions: Significance of HD

    Nagakura, T; Nagakura, Takanori; Omukai, Kazuyuki


    We study the evolution of gas in HII regions around the first stars after the death of the exciting stars. If the first star in a small halo dies without supernova (SN), subsequent star formation is possible in the same halo. We thus investigate the effect of ionization of the gas on subsequent star formation within small halos in the early universe using one-dimensional hydrodynamics with spherical symmetry along with non-equilibrium primordial gas chemistry. We find that the enhanced electron fraction facilitates the formation of molecular hydrogen at the cores of these halos. The low temperature circumstances produced by the H_2 cooling is suitable for HD formation and the resultant cooling further drops the temperature below 100 K. Consequently, low-mass stars with primordial abundances can form even in a small halo. After accreting the interstellar metals, these stars might resemble low-mass ultra metal-poor stars discovered in the present Galactic halo.

  2. Radiation-MHD simulations of pillars and globules in HII regions

    Mackey, Jonathan


    Implicit and explicit raytracing-photoionisation algorithms have been implemented in the author's radiation-magnetohydrodynamics code. The algorithms are described briefly and their efficiency and parallel scaling are investigated. The implicit algorithm is more efficient for calculations where ionisation fronts have very supersonic velocities, and the explicit algorithm is favoured in the opposite limit because of its better parallel scaling. The implicit method is used to investigate the effects of initially uniform magnetic fields on the formation and evolution of dense pillars and cometary globules at the boundaries of HII regions. It is shown that for weak and medium field strengths an initially perpendicular field is swept into alignment with the pillar during its dynamical evolution, matching magnetic field observations of the`Pillars of Creation' in M16. A strong perpendicular magnetic field remains in its initial configuration and also confines the photoevaporation flow into a bar-shaped, dense, ioni...

  3. Modelling Carbon Radio Recombination Line observation towards the Ultra-Compact HII region W48A

    Jeyakumar, S


    We model Carbon Recombination Line (CRL) emission from the Photo Dissociation Region (PDR) surrounding the Ultra-Compact (UC) HII region W48A. Our modelling shows that the inner regions ($A_V \\sim 1$) of the CII layer in the PDR contribute significantly to the CRL emission. The dependence of line ratios of CRL emission with the density of the PDR and the far ultra-violet (FUV) radiation incident on the region is explored over a large range of these parameters that are typical for the environments of UCHII regions. We find that by observing a suitable set of CRLs it is possible to constrain the density of the PDR. If the neutral density in the PDR is high ($\\gtrsim 10^7$ \\cmthree) CRL emission is bright at high frequencies ($\\gtrsim 20$ GHz), and absorption lines from such regions can be detected at low frequencies ($\\lesssim 10$ GHz). Modelling CRL observations towards W48A shows that the UCHII region is embedded in a molecular cloud of density of about $4 \\times$ 10$^7$ \\cmthree.

  4. The filling factor - radius relation for 58 HII regions across the disk of NGC6946

    Cedrés, B; Bongiovanni, A; Cepa, J; Ramos, A Asensio; Giammanco, C; Cabrera-Lavers, A; Alfaro, E


    Using the OSIRIS tunable narrow band imager on the 10.4m GTC (La Palma) we have mapped the SAB(rs)cd galaxy NGC 6946 over a 7.3x7.5 square arcminutes field in the emission lines of the [SII]\\lambda\\lambda, 6717, 6731 doublet, and in H\\alpha. From these maps we have produced catalogs of the H\\alpha luminosities and effective radii of 557 HII regions across the disk, and derived the [SII] emission line ratios of 370 of these. The H\\alpha observations were used to derive the mean luminosity-weighted electron densities for the regions of the sample, while the [SII] line ratios allowed us to derive values of the in situ electron densities in the denser zones from which the major fraction of the radiation in these lines is emitted, for 58 of the regions. This is by far the largest data set of its kind for a single galaxy. A classical two phase model is used to derive the filling factors of the regions. We find that although the mean electron density decreases with the square root of the radius of the regions, the i...

  5. Dusty Cradles in a Turbulent Nursery: The Sgr A East HII Region Complex at the Galactic Center

    Lau, Ryan; Morris, Mark; Adams, Joe


    We present imaging at 19, 25, 31, and 37 {\\mu}m of the compact HII region complex G-0.02-0.07 located 6 pc in projection from the center of the Galaxy obtained with SOFIA using FORCAST. G-0.02-0.07 contains three compact HII regions (A, B, and C) and one ultra-compact HII region (D). Our observations reveal the presence of two faint, infrared sources located 23'' and 35'' to the east of region C (FIRS 1 and 2) and detect dust emission in two of the three "ridges" of ionized gas west of region A. The 19/37 color temperature and 37 {\\mu}m optical depth maps of regions A - C are used to characterize the dust energetics and morphology. Regions A and B exhibit average 19/37 color temperatures of ~105 K, and regions C and D exhibit color temperatures of ~115 K and ~130 K, respectively. Using the DustEM code we model the SEDs of regions A - D and FIRS 1, all of which require populations of very small, transiently heated grains and large, equilibrium-heated grains. We also require the presence of polycyclic aromatic ...

  6. Spectral line survey of the ultracompact HII region Monoceros R2

    Ginard, D.; González-García, M.; Fuente, A.; Cernicharo, J.; Alonso-Albi, T.; Pilleri, P.; Gerin, M.; García-Burillo, S.; Ossenkopf, V.; Rizzo, J. R.; Kramer, C.; Goicoechea, J. R.; Pety, J.; Berné, O.; Joblin, C.


    Context. Ultracompact (UC) Hii regions constitute one of the earliest phases in the formation of a massive star and are characterized by extreme physical conditions (G0 > 105 Habing field and n > 106 cm-3). The UC Hii Mon R2 is the closest example and an excellent target to study the chemistry in these complex regions. Aims: Our goal is to investigate the chemistry of the molecular gas around UC Hii Mon R2 and the variations caused by the different local physical conditions. Methods: We carried out 3 mm and 1 mm spectral surveys using the IRAM 30-m telescope towards three positions that represent different physical environments in Mon R2: (i) the ionization front (IF) at (0″, 0″), and two peaks in the molecular cloud; (ii) molecular Peak 1 (hereafter MP1) at the offset (+15″, -15″); and (iii) molecular Peak 2 (hereafter MP2) at the farther offset (0″, 40″). In addition, we carried out extensive modeling to explain the chemical differences between the three observed regions. Results: We detected more than 30 different species (including isotopologues and deuterated compounds). In particular, we detected SO+ and C4H confirming that ultraviolet (UV) radiation plays an important role in the molecular chemistry of this region. In agreement with this interpretation, we detected the typical photo-dissociation region (PDR) molecules CN, HCN, HCO, C2H, and c-C3H2. There are chemical differences between the observed positions. While the IF and the MP1 have a chemistry similar to that found in high UV field and dense PDRs such as the Orion Bar, the MP2 is similar to lower UV/density PDRs such as the Horsehead nebula. Our chemical modeling supports this interpretation. In addition to the PDR-like species, we detected complex molecules such as CH3CN, H2CO, HC3N, CH3OH, and CH3C2H that are not usually found in PDRs. The sulfur compounds CS, HCS+, C2S, H2CS, SO, and SO2 and the deuterated species DCN and C2D were also identified. The origin of these complex species

  7. Star formation towards the southern Cometary HII region IRAS 17256-3631

    Veena, V S; Tej, A; Varricatt, W P; Ghosh, S K; Chandrasekhar, T; Ashok, N M


    IRAS 17256-3631 is a southern Galactic massive star forming region located at a distance of 2 kpc. In this paper, we present a multiwavelength investigation of the embedded cluster, the HII region, as well as the parent cloud. Radio images at 325, 610 and 1372 MHz were obtained using GMRT, India while the near-infrared imaging and spectroscopy were carried out using UKIRT and Mt. Abu Infrared Telescope, India. The near-infrared K-band image reveals the presence of a partially embedded infrared cluster. The spectral features of the brightest star in the cluster, IRS-1, spectroscopically agrees with a late O or early B star and could be the driving source of this region. Filamentary H_2 emission detected towards the outer envelope indicates presence of highly excited gas. The parent cloud is investigated at far-infrared to millimeter wavelengths and eighteen dust clumps have been identified. The spectral energy distributions (SEDs) of these clumps have been fitted as modified blackbodies and the best-fit peak t...

  8. Triggered massive star formation associated with the bubble Hii region Sh2-39 (N5)

    Duronea, N. U.; Cappa, C. E.; Bronfman, L.; Borissova, J.; Gromadzki, M.; Kuhn, M. A.


    Aims: We perform a multiwavelength analysis of the bubble Hii region Sh2-39 (N5) and its environs with the aim of studying the physical properties of Galactic IR bubbles and exploring their impact in triggering massive star formation. Methods: To analyze the molecular gas, we used CO(3-2) and HCO+(4-3) line data obtained with the on-the-fly technique from the ASTE telescope. To study the distribution and physical characteristics of the dust, we made use of archival data from ATLASGAL, Herschel, and MSX, while the ionized gas was studied making use of an NVSS image. We used public WISE, Spitzer, and MSX point source catalogs to search for infrared candidate young stellar objects (YSOs) in the region. To investigate the stellar cluster [BDS2003]6 we used IR spectroscopic data obtained with the ARCoIRIS spectrograph, mounted on Blanco 4 m Telescope at CTIO, and new available IR Ks band observations from the VVVeXtended ESO Public Survey (VVVX). Results: The new ASTE observations allowed the molecular gas component in the velocity range from 30 km s-1 to 46 km s-1, associated with Sh2-39, to be studied in detail. The morphology of the molecular gas suggests that the ionized gas is expanding against its parental cloud. We identified four molecular clumps, which were likely formed by the expansion of the ionization front, and determined some of their physical and dynamical properties. Clumps with HCO+ and 870 μm counterparts show evidence of gravitational collapse. We identified several candidate YSOs across the molecular component. Their spatial distribution and the fragmentation time derived for the collected layers of the molecular gas suggest that massive star formation might have been triggered by the expansion of the nebula via the collect and collapse mechanism. The spectroscopical distance obtained for the stellar cluster [BDS2003]6, placed over one of the collapsing clumps in the border of the Hii region, reveals that this cluster is physically associated with

  9. The environment and star formation of HII region Sh2-163: a multi-wavelength study

    Yu, Naiping; Li, Nan


    To investigate the environment of HII region Sh2-163 and search for evidence of triggered star formation in this region, we performed a multi-wavelength study of this HII region. Most of our data were taken from large-scale surveys: 2MASS, CGPS, MSX and SCUBA. We also made CO molecular line observations, using the 13.7-m telescope. The ionized region of Sh2-163 is detected by both the optical and radio continuum observations. Sh2-163 is partially bordered by an arc-like photodissociation region (PDR), which is coincident with the strongest optical and radio emissions, indicating interactions between the HII region and the surrounding interstellar medium. Two molecular clouds were discovered on the border of the PDR. The morphology of these two clouds suggests they are compressed by the expansion of Sh2-163. In cloud A, we found two molecular clumps. And it seems star formation in clump A2 is much more active than in clump A1. In cloud B, we found new outflow activities and massive star(s) are forming inside. ...

  10. Formation of Pillars at the Boundaries between HII Regions and Molecular Clouds

    Mizuta, A; Kane, J O; Pound, M W; Remington, B A; Ryutov, D D; Takabe, H


    We investigate numerically the hydrodynamic instability of an ionization front (IF) accelerating into a molecular cloud, with imposed initial perturbations of different amplitudes. When the initial amplitude is small, the imposed perturbation is completely stabilized and does not grow. When the initial perturbation amplitude is large enough, roughly the ratio of the initial amplitude to wavelength is greater than 0.02, portions of the IF temporarily separate from the molecular cloud surface, locally decreasing the ablation pressure. This causes the appearance of a large, warm HI region and triggers nonlinear dynamics of the IF. The local difference of the ablation pressure and acceleration enhances the appearance and growth of a multimode perturbation. The stabilization usually seen at the IF in the linear regimes does not work due to the mismatch of the modes of the perturbations at the cloud surface and in density in HII region above the cloud surface. Molecular pillars are observed in the late stages of the large amplitude perturbation case. The velocity gradient in the pillars is in reasonably good agreement with that observed in the Eagle Nebula. The initial perturbation is imposed in three different ways: in density, in incident photon number flux, and in the surface shape. All cases show both stabilization for a small initial perturbation and large growth of the second harmonic by increasing amplitude of the initial perturbation above a critical value.

  11. Anomalous Microwave Emission in HII regions: is it really anomalous? The case of RCW 49

    Paladini, Roberta; Agliozzo, Claudia; Tibbs, Christopher T; Noriega-Crespo, Alberto; Umana, Grazia; Dickinson, Clive; Trigilio, Corrado


    The detection of an excess of emission at microwave frequencies with respect to the predicted free-free emission has been reported for several Galactic HII regions. Here, we investigate the case of RCW 49, for which the Cosmic Background Imager tentatively (~ 3 sigma) detected Anomalous Microwave Emission at 31 GHz on angular scales of 7'. Using the Australia Telescope Compact Array, we carried out a multi-frequency (5 GHz, 19 GHz and 34 GHz) continuum study of the region, complemented by observations of the H109$\\alpha$ radio recombination line. The analysis shows that: 1) the spatial correlation between the microwave and IR emission persists on angular scales from 3.4' to 0.4", although the degree of the correlation slightly decreases at higher frequencies and on smaller angular scales, 2) the spectral indices between 1.4 and 5 GHz are globally in agreement with optically thin free-free emission, however, ~ 30% of these are positive and much greater than -0.1, consistently with a stellar wind scenario, 3) n...

  12. The RMS Survey: Resolving kinematic distance ambiguities towards a sample of compact HII regions using HI absorption

    Urquhart, J S; Lumsden, S L; Oudmaijer, R D; Moore, T J T; Mottram, J C; Cooper, H D B; Mottram, M; Rogers, H C


    We present high-resolution HI data obtained using the Australia Telescope Compact Array to resolve the near/far distance ambiguities towards a sample of compact HII regions from the Red MSX Source (RMS) survey. The high resolution data are complemented with lower resolution archival HI data extracted from the Southern and VLA Galactic Plane surveys. We resolve the distance ambiguity for nearly all of the 105 sources where the continuum was strong enough to allow analysis of the HI absorption line structure. This represents another step in the determination of distances to the total RMS sample, which with over 1,000 massive young stellar objects and compact HII regions, is the largest and most complete sample of its kind. The full sample will allow the distribution of massive star formation in the Galaxy to be examined.

  13. The relation between radio flux density and ionizing ultra-violet flux for HII regions and supernova remnants in the Large Magellanic cloud

    Filipović M.D.


    Full Text Available We present a comparison between the Parkes radio surveys (Filipović et al 1995 and Vacuum Ultra-Violet (VUV surveys (Smith et al. 1987 of the Large Magellanic Clouds (LMC. We have found 72 sources in common in the LMC which are known HII regions (52 and supernova remnants (SNRs (19. Some of these radio sources are associated with two or more UV stellar associations. A comparison of the radio flux densities and ionizing UV flux for HII regions shows a very good correlation, as expected from theory. Many of the Magellanic Clouds (MCs SNRs are embedded in HII regions, so there is also a relation between radio and UV which we attribute to the surrounding HII regions.

  14. Radiation-MHD models of elephant trunks and globules in HII regions

    Mackey, Jonathan; Lim, Andrew J.


    We study the formation and evolution of pillars of dense gas, known as elephant trunks, at the boundaries of HII regions, formed by shadowing of ionising radiation by dense clumps. The effects of magnetic fields on this process are investigated using 3D radiation-magnetohydrodynamics simulations. For a simulation in which an initially uniform magnetic field of strength \\vert B\\vert≃50 μG is oriented perpendicular to the radiation propagation direction, the field is swept into alignment with the pillar during its dynamical evolution, in agreement with observations of the ``Pillars of Creation'' in M16, and of some cometary globules. This effect is significantly enhanced when the simulation is re-run with a weaker field of ≃18 μG. A stronger field with \\vert B\\vert≃ 160 μG is sufficient to prevent this evolution completely, also significantly affecting the photoionisation process. Using a larger simulation domain it is seen that the pillar formation models studied in Mackey & Lim (2010) ultimately evolve to cometary structures in the absence of dense gas further from the star.

  15. Detailed Numerical Simulations on the Formation of Pillars around HII-regions

    Gritschneder, Matthias; Naab, Thorsten; Walch, Stefanie


    We study the structural evolution of turbulent molecular clouds under the influence of ionizing radiation emitted from a nearby massive star by performing a high resolution parameter study with the iVINE code. The temperature is taken to be 10K or 100K, the mean number density is either 100cm^3 or 300cm^3. Besides, the turbulence is varied between Mach 1.5 and Mach 12.5 and the main driving scale between 1pc and 8pc. We vary the ionizing flux by an order of magnitude. In our simulations the ionizing radiation enhances the initial turbulent density distribution and thus leads to the formation of pillar-like structures observed adjacent to HII regions in a natural way. Gravitational collapse occurs regularly at the tips of the structures. We find a clear correlation between the initial state of the turbulent cold cloud and the final morphology and physical properties of the structures formed. The most favorable regime for the formation of pillars is Mach 4-10. Structures and therefore stars only form if the ini...

  16. NEBU_3D afast pseudo-3D photoionization code for aspherical planetary nebulae and HII regions

    Morisset, C; Peña, M


    We describe a pseudo-3D photoionization code, NEBU_3D and its associated visualization tool, VIS_NEB3D, which are able to easily and rapidly treat a wide variety of nebular geometries, by combining models obtained with a 1D photoionization code. We also present a tool, VELNEB_3D, which can be applied to the results of 1D or 3D photoionization codes to generate emission line profiles, position-velocity maps and 3D maps in any emission line by assuming an arbitrary velocity field. As examples of the capabilities of these new tools, we consider three very different theoretical cases. The first one is a blister HII region, for which we have also constructed a spherical model (the spherical impostor) which has exactly the same Hbeta surface brightness distribution as the blister model and the same ionizing star. The second example shows how complex line profiles can be obtained even with a simple expansion law if the nebula is bipolar and the slit slightly off-center. The third example shows different ways to prod...

  17. Heavy elements in Galactic and Magellanic Cloud HII regions recombination-line versus forbidden-line abundances

    Tsamis, Y G; Liu, X W; Danziger, I J; Storey, P J; Tsamis, Yiannis G.


    We have obtained deep optical, long-slit spectrophotometry of the Galactic HII regions M 17, NGC 3576 and of the Magellanic Cloud HII regions 30 Doradus, LMC N11B and SMC N66, recording the optical recombination lines (ORLs) of CII, NII and OII. Temperature-insensitive ORL C2+/O2+ and N2+/O2 ratios are obtained for all nebulae except SMC N66. The ORL C2+/O2+ ratios show remarkable agreement within each galactic system, while also being in agreement with the corresponding CEL ratios. For all five nebulae, the O2+/H+ abundance derived from multiple OII ORLs is found to be higher than the corresponding value derived from the strong [OIII] 4959, 5007A CELs, by factors of 1.8--2.7 for four of the nebulae. The LMC N11B nebula exhibits a more extreme discrepancy factor for the O2+ ion, ~5. Thus these HII regions exhibit ORL/CEL abundance discrepancy factors that are similar to those previously encountered amongst planetary nebulae. Our optical CEL O2+/H+ abundances agree to within 20-30 per cent with published O2+/H...

  18. Dusty Cradles in a Turbulent Nursery: The Sgr A East HII Region Complex at the Galactic Center

    Lau, Ryan M.; Herter, Terry; Morris, Mark; Adams, Joseph


    We present high spatial resolution (FWHM ~ 3.2’’ - 3.8’’) imaging performed by the FORCAST instrument on SOFIA at 19, 25, 31, and 37 μm of the compact HII region complex G-0.02-0.07, the site of the most recent confirmed star formation within ~10 pc of the Galactic center. G-0.02-0.07 contains three compact HII regions (A, B, and C) and one ultra-compact HII region (D). Using this multiband imaging along with DustEM, we constrain the gas-to-dust mass ratios (~45 - 65) and the relative mass abundances of large grains, very small grains, and PAHs in the emitting dust from each region. Combining the inferred stellar luminosities, the expected and observed 1.90 μm fluxes and the observed dust thermal structure, the previously suggested heating sources for regions A, B, and C are confirmed. However, for region D, the observed fluxes at 1.87 and 1.90 μm of the previously proposed ionizing star are a factor of ~40 times too bright to be the heating source. We find that the location of the Region A heating source and the morphology of surrounding dust emission is consistent with that of a bow-shock, which suggests the heating source may have been ejected from its initial birth site rather than forming in-situ. In the ejection scenario for the Region A heating source, we estimate a lower limit on its age of ~104 yrs based on the size of the bow-shock.

  19. The galaxy-wide distributions of mean electron density in the HII regions of M51 and NGC 4449

    Gutiérrez, Leonel


    Using ACS-HST images to yield continuum subtracted photometric maps in H\\alpha of the Sbc galaxy M51 and the dwarf irregular galaxy NGC 4449, we produced extensive (over 2000 regions for M51, over 200 regions for NGC4449) catalogues of parameters of their HII regions: their H\\alpha luminosities, equivalent radii and coordinates with respect to the galaxy centers. From these data we derived, for each region, its mean luminosity weighted electron density, , determined from the H\\alpha luminosity and the radius, R, of the region. Plotting these densities against the radii of the regions we find excellent fits for varying as R^{-1/2}. This relatively simple relation has not, as far as we know, been predicted from models of HII region structure, and should be useful in constraining future models. Plotting the densities against the galactocentric radii, r, of the regions we find good exponential fits, with scale lengths of close to 10 kpc for both galaxies. These values are comparable to the scale lengths of the H...


    J. Vasquez


    Full Text Available En este trabajo presentamos un estudio multifrecuencia del medio interstelar en el entorno de la región HII Sh2-54. El gas molecular y el polvo se han analizado y descripto por medio de las observaciones milimétricas e infrarrojas, respectivamente. La emisión en 8.0 ¿Êm de Spitzer-IRAC presenta una compleja estructura filamentaria de gas fotodisociado, evidenciando la interacción entre la región HII y el gas molecular. Numerosos candidatos a objetos estelares jóvenes se encuentran proyectados sobre Sh2-54 y sus alrededores. Analizamos si la presencia de estos objetos puede ser explicada dentro de un escenario de formación estelar inducida.

  1. The interstellar medium and the massive stellar content toward the SNR G18.1-0.1 and neighboring HII regions

    Paron, S; Ortega, M E; Colombo, J F Albacete; Pichel, A


    We perform a multiwavelength study toward the SNR G18.1-0.1 and nearby several HII regions (infrared dust bubbles N21 and N22, and the HII regions G018.149-00.283 and G18.197-00.181). Our goal is to provide observational evidence supporting that massive stars usually born in clusters from the same molecular cloud, which then produce, along their evolution, different neighboring objects such as HII regions, interstellar bubbles and supernova remnants. We suggest that the objects analysed in this work belong to a same complex located at the distance of about 4 kpc. Using molecular data we inspected the interstellar medium toward this complex and from optical and X-ray observations we looked for OB-type stars in the region. Analysing public 13CO J=1--0 data we found several molecular structures very likely related to the HII region/SNR complex. We suggest that the molecular gas is very likely being swept and shaped by the expansion of the HII regions. From spectroscopic optical observations obtained with the 2.1...

  2. Bipolar HII regions - Morphology and star formation in their vicinity - I - G319.88$+$00.79 and G010.32$-$00.15

    Deharveng, L; Samal, M R; Anderson, L D; LeLeu, G; Brevot, D; Duarte-Cabral, A; Molinari, S; Pestalozzi, M; Foster, J B; Rathborne, J M; Jackson, J M


    Our goal is to identify bipolar HII regions and to understand their morphology, their evolution, and the role they play in the formation of new generations of stars. We use the Spitzer and Herschel Hi-GAL surveys to identify bipolar HII regions. We search for their exciting star(s) and estimate their distances using near-IR data. Dense clumps are detected using Herschel-SPIRE data. MALT90 observations allow us to ascertain their association with the central HII region. We identify Class 0/I YSOs using their Spitzer and Herschel-PACS emissions. These methods will be applied to the entire sample of candidate bipolar HII regions. This paper focuses on two bipolar HII regions, one interesting in terms of its morphology, G319.88$+$00.79, and one in terms of its star formation, G010.32$-$00.15. Their exciting clusters are identified and their photometric distances estimated to be 2.6 kpc and 1.75 kpc, respectively. We suggest that these regions formed in dense and flat structures that contain filaments. They have a...

  3. The first CO+ image. I. Probing the HI/H2 layer around the ultracompact HII region Mon R2

    Treviño-Morales, S. P.; Fuente, A.; Sánchez-Monge, Á.; Pilleri, P.; Goicoechea, J. R.; Ossenkopf-Okada, V.; Roueff, E.; Rizzo, J. R.; Gerin, M.; Berné, O.; Cernicharo, J.; Gónzalez-García, M.; Kramer, C.; García-Burillo, S.; Pety, J.


    The CO+ reactive ion is thought to be a tracer of the boundary between a Hii region and the hot molecular gas. In this study, we present the spatial distribution of the CO+ rotational emission toward the Mon R2 star-forming region. The CO+ emission presents a clumpy ring-like morphology, arising from a narrow dense layer around the Hii region. We compared the CO+ distribution with other species present in photon-dominated regions (PDR), such as [Cii] 158 μm, H2 S(3) rotational line at 9.3 μm, polycyclic aromatic hydrocarbons (PAHs), and HCO+. We find that the CO+ emission is spatially coincident with the PAHs and [Cii] emission. This confirms that the CO+ emission arises from a narrow dense layer of the Hi/H2 interface. We determined the CO+ fractional abundance relative to C+ toward three positions. The abundances range from 0.1 to 1.9 × 10-10 and are in good agreement with the previous chemical model, which predicts that the production of CO+ in PDRs only occurs in dense regions with high UV fields. The CO+ linewidth is larger than those found in molecular gas tracers, and their central velocity are blueshifted with respect to the molecular gas velocity. We interpret this as a hint that the CO+ is probing photoevaporating clump surfaces.

  4. The first CO+ image: Probing the HI/H2 layer around the ultracompact HII region Mon R2

    Trevino-Morales, S P; Sanchez-Monge, A; Pilleri, P; Goicoechea, J R; Ossenkopf-Okada, V; Roueff, E; Rizzo, J R; Gerin, M; Berne, O; Cernicharo, J; Gonzalez-Garcia, M; Kramer, C; Garcia-Burillo, S; Pety, J


    The CO+ reactive ion is thought to be a tracer of the boundary between a HII region and the hot molecular gas. In this study, we present the spatial distribution of the CO+ rotational emission toward the Mon R2 star-forming region. The CO+ emission presents a clumpy ring-like morphology, arising from a narrow dense layer around the HII region. We compare the CO+ distribution with other species present in photon-dominated regions (PDR), such as [CII] 158 mm, H2 S(3) rotational line at 9.3 mm, polycyclic aromatic hydrocarbons (PAHs) and HCO+. We find that the CO+ emission is spatially coincident with the PAHs and [CII] emission. This confirms that the CO+ emission arises from a narrow dense layer of the HI/H2 interface. We have determined the CO+ fractional abundance, relative to C+ toward three positions. The abundances range from 0.1 to 1.9x10^(-10) and are in good agreement with previous chemical model, which predicts that the production of CO+ in PDRs only occurs in dense regions with high UV fields. The CO...

  5. Near-IR integral field spectroscopy of ionizing stars and young stellar objects on the borders of HII regions

    Martins, F; Deharveng, L; Zavagno, A; Bouret, J -C


    We present near-IR SINFONI observations of three Galactic HII regions: RVW79, RCW82 and RCW120. We identify the ionizing stars of each region: they are early to late O stars, close to the main sequence. We derive their stellar and wind properties using atmosphere models computed with the code CMFGEN. The cluster ionizing RCW~79 formed 2.3+/-0.5 Myr ago. Similar ages are estimated, albeit with a larger uncertainty, for the ionizing stars of the other two regions. In RCW79 the mechanical wind luminosity represents only 0.1% of the ionizing luminosity, questioning the influence of stellar winds on the dynamics of the the HII region. The young stellar objects show four main types of spectral features: H2 emission, Br gamma emission, CO bandheads emission and CO bandheads absorption. These features are typical of young stellar objects surrounded by disks and/or envelopes. The radial velocities of most YSOs are consistent with that of the ionized gas, firmly establishing that star formation is taking place on the b...

  6. HII region G46.5-0.2: the interplay between ionizing radiation, molecular gas and star formation

    Paron, S; Dubner, G; Yuan, Jing-Hua; Petriella, A; Giacani, E; Li, Jin Zeng; Wu, Yuefang; Liu, Hongli; Huang, Ya Fang; Zhang, Si-Ju


    HII regions are particularly interesting because they can generate dense layers of gas and dust, elongated columns or pillars of gas pointing towards the ionizing sources, and cometary globules of dense gas, where triggered star formation can occur. Understanding the interplay between the ionizing radiation and the dense surrounding gas is very important to explain the origin of these peculiar structures, and hence to characterize triggered star formation. G46.5-0.2 (G46), a poorly studied galactic HII region located at about 4 kpc, is an excellent target to perform this kind of studies. Using public molecular data extracted from the Galactic Ring Survey (13CO J=1-0) and from the James Clerk Maxwell Telescope data archive (12CO, 13CO, C18O J=3-2, HCO+ and HCN J=4-3), and infrared data from the GLIMPSE and MIPSGAL surveys, we perform a complete study of G46, its molecular environment and the young stellar objects placed around it. We found that G46, probably excited by an O7V star, is located close to the edge...

  7. H$\\alpha$ tail, intracluster HII regions and star-formation: ESO137-001 in Abell 3627

    Sun, M; Voit, G M


    We present the discovery of a 40 kpc H-alpha tail and at least 29 emission-line objects downstream of a star-forming galaxy ESO 137-001 in a rich, nearby cluster A3627. The galaxy is known to possess a dramatic 70 kpc X-ray tail. The detected H-alpha tail coincides positionally with the X-ray tail. The H-alpha emission in the galaxy is sharply truncated on the front and the sides near the nucleus, indicating significant ram pressure stripping. ESO 137-001 is thus the first cluster late-type galaxy known with both an X-ray tail and an H-alpha tail. The emission-line objects are all distributed downstream of the galaxy, with projected distance up to 39 kpc from the galaxy. From the analysis on the H-alpha_{off} frame and the estimate of the background emission-line objects, we conclude that it is very likely all these 29 emission-line objects are HII regions associated with ESO 137-001. The high surface number density and luminosities of these HII regions (up to 10^40 ergs/s) largely dwarf the previously known ...

  8. An Alternative to Spinning Dust for the Microwave Emission of LPH 201.663+1.643 an Ultracompact HII Region

    McCullough, P R


    The microwave spectral energy distribution of the dusty, diffuse H II region LPH 201.663+1.643 has been interpreted by others as tentative evidence for microwave emission from spinning dust grains. We present an alternative interpretation for that particular object; specifically, that an ultracompact H II region embedded within the dust cloud would explain the available observations as well or better than spinning dust. Parameters for the size, surface brightness, and flux density of the putative ultracompact HII region, derived from the microwave observations, are within known ranges. A possible candidate for such an ultracompact H II region is IRAS 06337+1051, based upon its infrared colors. However, IRAS 06337+1051's infrared flux appears to be too small to be consistent with the microwave flux required for this alternative model to explain the observations.

  9. On the relative importance of different microphysics on the D-type expansion of galactic HII regions

    Haworth, Thomas J; Acreman, David M; Bisbas, Thomas G


    Radiation hydrodynamics (RHD) simulations are used to study many astrophysical phenomena, however they require the use of simplified radiation transport and thermal prescriptions to reduce computational cost. In this paper we present a systematic study of the importance of microphysical processes in RHD simulations using the example of D-type HII region expansion. We compare the simplest hydrogen-only models with those that include: ionisation of H, He, C, N, O, S and Ne, different gas metallicity, non-LTE metal line blanketed stellar spectral models of varying metallicity, radiation pressure, dust and treatment of photodissociation regions. Each of these processes are explicitly treated using modern numerical methods rather than parameterisation. In line with expectations, changes due to microphysics in either the effective number of ionising photons or the thermal structure of the gas lead to differences in D-type expansion. In general we find that more realistic calculations lead to the onset of D-type exp...

  10. Flickering of 1.3 cm Sources in Sgr B2: Towards a Solution to the Ultracompact HII Region Lifetime Problem

    De Pree, C G; Mac Low, M -M; Wilner, D J; Goss, W M; Galván-Madrid, R; Keto, E R; Klessen, R S; Monsrud, A


    Accretion flows onto massive stars must transfer mass so quickly that they are themselves gravitationally unstable, forming dense clumps and filaments. These density perturbations interact with young massive stars, emitting ionizing radiation, alternately exposing and confining their HII regions. As a result, the HII regions are predicted to flicker in flux density over periods of decades to centuries rather than increasing monotonically in size as predicted by simple Spitzer solutions. We have recently observed the Sgr B2 region at 1.3 cm with the VLA in its three hybrid configurations (DnC, CnB and BnA) at a resolution of 0.25''. These observations were made to compare in detail with matched continuum observations from 1989. At 0.25'' resolution, Sgr B2 contains 41 UC HII regions, 6 of which are hypercompact. The new observations of Sgr B2 allow comparison of relative peak flux densites for the HII regions in Sgr B2 over a 23 year time baseline (1989-2012) in one of the most source-rich massive star forming...

  11. Combined stellar structure and atmosphere models for massive stars; 4, The impact on the ionization structure of single star HII regions

    Stasinska, G; Stasinska, Grazyna; Schaerer, Daniel


    We study the impact of modern stellar atmospheres that take into account the effects of stellar winds, departures from LTE and line blanketing ("CoStar" models) on the ionization structure of HII regions. Results from a large grid of photoionization models are presented. Due to a flatter energy distribution in the HeI continuum, compared to the widely used Kurucz models, generally higher ionic ratios are obtained. We find that N+/O+ and Ne++/O++ can be safely used as direct indicators of N/O and Ne/O abundance ratios in HII regions, over a wide range of astrophysical situations. The roughly constant observed value of Ne++/O++ ionic ratios in Galactic HII regions is naturally reproduced by photoionization models using CoStar fluxes, while Kurucz models at solar metallicity fail to reproduce this behaviour. This gives support to ionizing fluxes from non-LTE atmospheres including stellar winds and line blanketing. However, we also point out that tests of stellar atmosphere models from observations of HII regions...

  12. A Herschel and BIMA study of the sequential star formation near the W48A HII region

    Rygl, K L J; Polychroni, D; Wyrowski, F; Motte, F; Elia, D; Nguyen-Luong, Q; Didelon, P; Pestalozzi, M; Benedettini, M; Molinari, S; Andre, Ph; Fallscheer, C; Gibb, A; di Giorgio, A M; Hill, T; Konyves, V; Marston, A; Pezzuto, S; Rivera-Ingraham, A; Schisano, E; Schneider, N; Spinoglio, L; Ward-Thompson, D; White, G J


    We present the results of Herschel HOBYS photometric mapping combined with BIMA observations and additional archival data, and perform an in-depth study of the evolutionary phases of the star-forming clumps in W 48A and their surroundings. Age estimates for the compact sources were derived from bolometric luminosities and envelope masses, which were obtained from the dust continuum emission, and agree within an order of magnitude with age estimates from molecular line and radio data. The clumps in W 48A are linearly aligned by age (east-old to west-young): we find a ultra compact (UC) HII region, a young stellar object (YSO) with class II methanol maser emission, a YSO with a massive outflow, and finally the NH_2D prestellar cores from Pillai et al. This remarkable positioning reflects the (star) formation history of the region. We find that it is unlikely that the star formation in the W 48A molecular cloud was triggered by the UCHII region and discuss the Aquila supershell expansion as a mayor influence on ...

  13. A young stellar cluster within the RCW41 HII region: deep NIR photometry and Optical/NIR polarimetry

    Santos, Fábio P; Franco, Gabriel A P


    The RCW41 star-forming region is embedded within the Vela Molecular Ridge, hosting a massive stellar cluster surrounded by a conspicuous HII region. Understanding the role of interstellar magnetic fields and studying the newborn stellar population is crucial to build a consistent picture of the physical processes acting on this kind of environment. We have carried out a detailed study of the interstellar polarization toward RCW41, with data from an optical and near-infrared polarimetric survey. Additionally, deep near-infrared images from the NTT 3.5m telescope have been used to study the photometric properties of the embedded young stellar cluster, revealing several YSO's candidates. By using a set of pre-main sequence isochrones, a mean cluster age in the range 2.5 - 5.0 million years was determined, and evidence of sequential star formation were revealed. An abrupt decrease in R-band polarization degree is noticed toward the central ionized area, probably due to low grain alignment efficiency caused by the...

  14. High Angular Resolution Imaging Spectroscopy of the Galactic Ultra-Compact HII Region K3-50A

    Blum, Robert D


    Gemini North adaptive optics imaging spectroscopy is presented for the Galactic ultra-compact HII (UCHII) region K3-50A. Data were obtained in the K-band using the Near-infrared Integral Field Spectrograph (NIFS) behind the facility adaptive optics module ALTAIR in natural guide star mode. The NIFS data cube reveals a complex spatial morphology across the 0.1 pc scale of the 3'' UCHII region. Comparison of the nebular emission to Cloudy ionization models shows that the central source must have an effective temperature between about 37000 K and 45000 K with preferred values near 40000 K. Evidence is presented for sharp density variations in the nebula which are interpreted as a clearing of material nearest the central source. High excitation lines of FeIII and SeIV show that the ionization of the nebula clearly changes with distance from the central source. A double lobed kinematic signature (+/- 25 kms) is evident in the Br gamma line map which may be related to the larger scale ionized flow detailed in earli...

  15. Abundance determination of multiple star-forming regions in the HII galaxy SDSS J165712.75+321141.4

    Hagele, Guillermo F; Perez-Montero, Enrique; Diaz, Angeles I; Cardaci, Monica V; Firpo, Veronica; Terlevich, Elena; Terlevich, Roberto


    We analyze high signal-to-noise spectrophotometric observations acquired simultaneously with TWIN, a double-arm spectrograph, from 3400 to 10400 \\AA of three star-forming regions in the HII galaxy SDSS J165712.75+321141.4. We have measured four line temperatures: Te([OIII]), Te([SIII]), Te([OII]), and Te([SII]), with high precision, rms errors of order 2%, 5%, 6% and 6%, respectively, for the brightest region, and slightly worse for the other two. The temperature measurements allowed the direct derivation of ionic abundances of oxygen, sulphur, nitrogen, neon and argon. We have computed CLOUDY tailor-made models which reproduce the O2+ measured thermal and ionic structures within the errors in the three knots, with deviations of only 0.1 dex in the case of O+ and S2+ ionic abundances. In the case of the electron temperature and the ionic abundances of S+/H+, we find major discrepancies which could be consequence of the presence of colder diffuse gas. The star formation history derived using STARLIGHT shows a ...

  16. Integral field spectroscopy of the two complexes of HII regions in the main galaxy of the minor merger AM2306-721

    Hernandez-Jimenez, J. A.; Pastoriza, G.; Sanmartim, D.; Winge, C.; Bonatto, C.; Krabbe, A. C.; Rodrigues, I.


    We present a study of two complexes of HII regions in the main galaxy of minor merger AM 2306-721. The observations were obtained with the GMOS-IFU on the Gemini South telescope. By using different discrimination criteria, we determined that shock-ionized gas fraction ranges between 0% and 35%, which are in good agreement with numerical models. Thus, we conclude that almost all the mechanical energy from stellar winds and supernovae is being irradiated.

  17. Small-spatial scale variations of nebular properties and the abundance discrepancy in three Galactic HII regions

    Mesa-Delgado, A


    We present results of long-slit spectroscopy in several slit positions that cover different morphological structures of the central parts of three bright Galactic HII regions: M8, M17 and NGC7635. We study the spatial distributions of a large number of nebular parameters such as the extinction coefficient, line fluxes, physical conditions and ionic abundances at the maximum spatial resolution attainable with our instrumentation. Particularly, our goal is to study the behaviour of the abundance discrepancy factor of O^{2+}, ADF(O^{2+}), defined as the logarithmic difference of the O^{2+} abundances derived from collisionally excited and recombination lines. We find that the ADF(O^{2+}) remains fairly constant along the slit positions of M8 and M17. In the case of NGC7635, we only detect the OII recombination lines in the integrated spectrum along the whole slit, where the ADF(O^{2+}) reaches a remarkably high value of about 0.59 dex. We compare our results with previous ones obtained for the Orion Nebula. We f...

  18. The Ionizing Stars of the Galactic Ultra-Compact HII Region G45.45+0.06

    Blum, Robert D


    Using the NIFS near-infrared integral-field spectrograph behind the facility adaptive optics module, ALTAIR, on Gemini North, we have identified several massive O-type stars that are responsible for the ionization of the Galactic Ultra-Compact HII region G45.45+0.06. The sources ``m'' and ``n'' from the imaging study of Feldt et a. 1998 are classified as hot, massive O-type stars based on their K-band spectra. Other bright point sources show red and/or nebular spectra and one appears to have cool star features that we suggest are due to a young, low-mass pre-main sequence component. Still two other embedded sources (``k'' and ``o'' from Feldt et al.) exhibit CO bandhead emission that may arise in circumstellar disks which are possibly still accreting. Finally, nebular lines previously identified only in higher excitation planetary nebulae and associated with KrIII and SeIV ions are detected in G45.45+0.06.

  19. Denser Sampling of the Rosette Nebula with Faraday Rotation Measurements: Improved Estimates of Magnetic Fields in HII Regions

    Costa, Allison H; Sink, Joseph R; Brown, Shea; Mao, Sui Ann


    We report Faraday rotation measurements of 11 extragalactic radio sources with lines of sight through the Rosette Nebula, a prominent HII region associated with the star cluster NGC 2244. It is also a prototypical example of a "stellar bubble" produced by the winds of the stars in NGC 2244. The goal of these measurements is to better determine the strength and structure of the magnetic field in the nebula. We calculate the rotation measure (RM) through two methods, a least-squares fit to $\\chi$( $\\lambda^2$) and Rotation Measure Synthesis. In conjunction with our results from Savage et al. (2013), we find an excess RM due to the shell of the nebula of +40 to +1200 rad m$^{-2}$ above a background RM of +147 rad m$^{-2}$. We discuss two forms of a simple shell model intended to reproduce the magnitude of the observed RM as a function of distance from the center of the Rosette Nebula. The models represent different physical situations for the magnetic field within the shell of the nebula. The first assumes that ...

  20. Helium in natal HII regions: the origin of the X-ray absorption in gamma-ray burst afterglows

    Watson, Darach; Andersen, Anja C; Fynbo, Johan P U; Gorosabel, Javier; Hjorth, Jens; Jakobsson, Páll; Krühler, Thomas; Laursen, Peter; Leloudas, Giorgos; Malesani, Daniele


    Soft X-ray absorption in excess of Galactic is observed in the afterglows of most gamma-ray bursts (GRBs), but the correct solution to its origin has not been arrived at after more than a decade of work, preventing its use as a powerful diagnostic tool. We resolve this long-standing problem and find that He in the GRB's host HII region is responsible for most of the absorption. We show that the X-ray absorbing column density (N_Hx) is correlated with both the neutral gas column density and with the optical afterglow extinction (Av). This correlation explains the connection between dark bursts and bursts with high N_Hx values. From these correlations we exclude an origin of the X-ray absorption which is not related to the host galaxy, i.e. the intergalactic medium or intervening absorbers are not responsible. We find that the correlation with the dust column has a strong redshift evolution, whereas the correlation with the neutral gas does not. From this we conclude that the column density of the X-ray absorpt...

  1. VizieR Online Data Catalog: IRX-β relation of HII regions in NGC628 (Ye+, 2016)

    Ye, C.; Zou, H.; Lin, L.; Lian, J.; Hu, N.; Kong, X.


    NGC 628 has been observed by the PPAK IFS Nearby Galaxies Survey (PINGS) performed by the 3.5m telescope of the Calar Alto Observatory. The IFU provides a sampling of 2.7", an optical wavelength range of 3700-7000Å with a spectral resolution of ~8Å. The final data set comprises 11094 individual spectra, and the typical spatial resolution is about 3.5"-4". The slice image at the Hα wavelength is used to determine HII regions. FUV and near-UV (NUV) images of NGC 628 were taken by the Galaxy Evolution Explorer (GALEX), which are centered at wavelengths of 1516 and 2267Å. IR images were taken by Spitzer IRAC (3.6um, 8.0um) and MIPS (24um). The spatial resolutions of UV and IR images are 4.3", 5.3", 1.9", 2.8", and 6.4", respectively. We obtain these images from the data release website of Local Volume Legacy (LVL) survey DR5 (Dale+, 2009, J/ApJ/703/517; (2 data files).

  2. ISO spectroscopy of compact HII regions in the Galaxy - II. Ionization and elemental abundances

    Martin-Hernandez, NL; Peeters, E; Morisset, C; Tielens, AGGM; Cox, P; Roelfsema, PR; Baluteau, JP; Schaerer, D; Mathis, JS; Damour, F; Churchwell, E; Kessler, MF


    Based on the ISO spectral catalogue of compact H II regions by Peeters et al. (2002), we present a first analysis of the hydrogen recombination and atomic fine-structure lines originated in the ionized gas. The sample consists of 34 H II regions located at galactocentric distances between R-Gal = 0

  3. The Orion HII Region and the Orion Bar in the Mid-infrared

    Salgado, F.; Berné, O.; Adams, J. D.; Herter, T. L.; Keller, L. D.; Tielens, A. G. G. M.


    We present mid-infrared photometry of the Orion bar obtained with the Faint Object infraRed Camera for the SOFIA Telescope (FORCAST) on board SOFIA at 6.4, 6.6, 7.7, 19.7, 31.5, and 37.1 μm. By complementing this observation with archival FORCAST and Herschel/PACS images, we are able to construct a complete infrared spectral energy distribution of the Huygens region in the Orion nebula. Comparing the infrared images with gas tracers, we find that PACS maps trace the molecular cloud, while the FORCAST data trace the photodissociation region (PDR) and the H ii region. Analysis of the energetics of the region reveal that the PDR extends for 0.28 pc along the line of sight and that the bar is inclined at an angle of 4°. The infrared and submillimeter images reveal that the Orion bar represents a swept-up shell with a thickness of 0.1 pc. The mass of the shell implies a shock velocity of ≃3 km s-1 and an age of ≃105 years for the H ii region. Our analysis shows that the UV and infrared dust opacities in the H ii region and the PDR are a factor 5 to 10 lower than in the diffuse interstellar medium. In the ionized gas, Lyα photons are a major source of dust heating at distances larger than ≃0.06 pc from θ 1 Ori C. Dust temperatures can be explained if the size of the grains is between 0.1 and 1 μm. We derive the photoelectric heating efficiency of the atomic gas in the Orion bar. The results are in good qualitative agreement with models and the quantitative differences indicate a decreased polycyclic aromatic hydrocarbon abundance in this region.

  4. Oxygen abundance distributions in six late-type galaxies based on SALT spectra of HII regions

    Zinchenko, I A; Grebel, E K; Pilyugin, L S


    Spectra of 34 H II regions in the late-type galaxies NGC1087, NGC2967, NGC3023, NGC4030, NGC4123, and NGC4517A were observed with the South African Large Telescope (SALT). In all 34 H II regions, oxygen abundances were determined through the "counterpart" method (C method). Additionally, in two H II regions in which the auroral lines were detected oxygen abundances were measured through the classic Te method. We also estimated the abundances in our H II regions using the O3N2 and N2 calibrations and compared those with the C-based abundances. With these data we examined the radial abundance distributions in the disks of our target galaxies. We derived surface-brightness profiles and other characteristics of the disks (the surface brightness at the disk center and the disk scale length) in three photometric bands for each galaxy using publicly available photometric imaging data. The radial distributions of the oxygen abundances predicted by the relation between abundance and disk surface brightness in the W1 b...

  5. Populations of High-Luminosity Density-Bounded HII Regions in Spiral Galaxies? Evidence and Implications

    Beckman, J. E.; Rozas, M.; Zurita, A.; Watson, R. A.; Knapen, J. H.


    In this paper we present evidence that the H II regions of high luminosity in disk galaxies may be density bounded, so that a significant fraction of the ionizing photons emitted by their exciting OB stars escape from the regions. The key piece of evidence is the presence, in the Ha luminosity functions (LFs) of the populations of H iI regions, of glitches, local sharp peaks at an apparently invariant luminosity, defined as the Stromgren luminosity Lstr), LH(sub alpha) = Lstr = 10(sup 38.6) (+/- 10(sup 0.1)) erg/ s (no other peaks are found in any of the LFs) accompanying a steepening of slope for LH(sub alpha) greater than Lstr This behavior is readily explicable via a physical model whose basic premises are: (a) the transition at LH(sub alpha) = Lstr marks a change from essentially ionization bounding at low luminosities to density bounding at higher values, (b) for this to occur the law relating stellar mass in massive star-forming clouds to the mass of the placental cloud must be such that the ionizing photon flux produced within the cloud is a function which rises more steeply than the mass of the cloud. Supporting evidence for the hypothesis of this transition is also presented: measurements of the central surface brightnesses of H II regions for LH(sub alpha) less than Lstr are proportional to L(sup 1/3, sub H(sub alpha)), expected for ionization bounding, but show a sharp trend to a steeper dependence for LH(sub alpha) greater than Lstr, and the observed relation between the internal turbulence velocity parameter, sigma, and the luminosity, L, at high luminosities, can be well explained if these regions are density bounded. If confirmed, the density-bounding hypothesis would have a number of interesting implications. It would imply that the density-bounded regions were the main sources of the photons which ionize the diffuse gas in disk galaxies. Our estimates, based on the hypothesis, indicate that these regions emit sufficient Lyman continuum not only to

  6. VizieR Online Data Catalog: Radio observations of Galactic WISE HII regions (Anderson+, 2015)

    Anderson, L. D.; Armentrout, W. P.; Johnstone, B. M.; Bania, T. M.; Balser, D. S.; Wenger, T. V.; Cunningham, V.


    We draw our targets from the MIR objects in the WISE catalog of Anderson+, 2014, J/ApJS/212/1. We also include in our sample Sharpless H II regions (Sharpless 1959, VII/20). See section 2 for further details. Our observations were made with the GBT 100m telescope from 2012 July through 2014 August. There are seven radio recombination lines (RRLs) that can be cleanly observed simultaneously with the GBT in the X-band: H87α to H93α. We average these seven RRLs (each at two orthogonal polarizations) to create a single average RRL spectrum. We followed the same GBT observational procedure as in the original HRDS (Green Bank Telescope H II Region Discovery Survey (GBT HRDS; Bania et al. 2010ApJ...718L.106B). (3 data files).

  7. Production of Elephant Trunks in HII Regions by Radiation-Magnetohydrodynamic Instabilities

    Fierlinger, Katharina; Krumholz, Mark; Grittschneder, Matthias


    Recent SPH and grid code simulations showed, that ionizing radiation can amplify overdensities in turbulent molecular clouds and produce molecular pillars. The relevance of magnetic fields for the structure and stability of molecular clouds is still under discussion. We investigate whether an ionization front hitting a medium with small distortions of the magnetic field can produce the observed pillar-like structures in star forming regions (e.g. Eagle Nebula). Numerical MHD simulations with ...

  8. Physical properties of the Sh2-104 HII region as seen by Herschel

    Rodón, J A; Baluteau, J -P; Anderson, L D; Polehampton, E; Abergel, A; Motte, F; Bontemps, S; Ade, P; André, P; Arab, H; Beichman, C; Bernard, J -P; Blagrave, K; Boulanger, F; Cohen, M; Compiegne, M; Cox, P; Dartois, E; Davis, G; Emery, R; Fulton, T; Gry, C; Habart, E; Halpern, M; Huang, M; Joblin, C; Jones, S C; Kirk, J; Lagache, G; Lin, T; Madden, S; Makiwa, G; Martin, P; Miville-Deschênes, M -A; Molinari, S; Moseley, H; Naylor, D; Okumura, K; Orieux, F; Gonçalvez, D Pinheiro; Rodet, T; Russeil, D; Saraceno, P; Sidher, S; Spencer, L; Swinyard, B; Ward-Thompson, D; White, G


    Context: Sh2-104 is a Galactic H ii region with a bubble morphology, detected at optical and radio wavelengths. It is considered the first observational confirmation of the collect-and-collapse model of triggered star-formation. Aims: We aim to analyze the dust and gas properties of the Sh2-104 region to better constrain its effect on local future generations of stars. In addition, we investigate the relationship between the dust emissivity index {\\beta} and the dust temperature, T_dust. Methods: Using Herschel PACS and SPIRE images at 100, 160, 250, 350 and 500 {\\mu}m we determine T_dust and {\\beta} throughout Sh2-104, fitting the spectral energy distributions (SEDs) obtained from aperture photometry. With the SPIRE Fourier transform spectrometer (FTS) we obtained spectra at different positions in the Sh2-104 region. We detect J-ladders of CO and 13CO, with which we derive the gas temperature and column density. We also detect proxies of ionizing flux as the [NII] 3P1-3P0 and [CI] 3P2-3P1 transitions. Result...

  9. A radiation driven implosion model for the enhanced luminosity of protostars near HII regions

    Motoyama, K; Shang, H


    Context. Molecular clouds near the H II regions tend to harbor more luminous protostars. Aims. Our aim in this paper is to investigate whether or not radiation-driven implosion mechanism enhances luminosity of protostars near regions of high-ionizing fluxes. Methods. We performed numerical simulations to model collapse of cores exposed to UV radiation from O stars. We investigated dependence of mass loss rates on the initial density profiles of cores and variation of UV fluxes. We derived simple analytic estimates of accretion rates and final masses of protostars. Results. Radiation-driven implosion mechanism can increase accretion rates of protostars by 1-2 orders of magnitude. On the other hand, mass loss due to photo-evaporation is not large enough to have a significant impact on the luminosity. The increase of accretion rate makes luminosity 1-2 orders higher than those of protostars that form without external triggering. Conclusions. Radiation-driven implosion can help explain the observed higher luminos...

  10. Physical and chemical properties of Red MSX Sources in the southern sky: HII regions

    Yu, Naiping; Li, Nan


    We have studied the physical and chemical properties of 18 southern Red Midcourse Space Experiment Sources (RMSs), using archival data taken from the Atacama Pathfinder Experiment (APEX) Telescope Large Area Survey of the Galaxy, the Australia Telescope Compact Array, and the Millimeter Astronomy Legacy Team Survey at 90 GHz. Most of our sources have simple cometary/unresolved radio emissions at 4.8 and/or 8.6GHz. The large number of Lyman continuum fluxes (NL) indicates they are probably massive O- or early B-type star formation regions. Archival IRAS infrared data are used to estimate the dust temperature, which is about 30 K of our sources. Then, the H2 column densities and the volume-averaged H2 number densities are estimated using the 0.87 mm dust emissions. Large-scale infall and ionized accretions may be occurring in G345.4881+00.3148. We also attempt to characterize the chemical properties of these RMSs through molecular line (N2H+ (1-0) and HCO+ (1-0)) observations. Most of the detected N2H+ and HCO+...

  11. The Herschel view of HII regions in M 33 (HERM33ES)

    Verley, S.; Relaño, M.; Kramer, C.; Xilouris, E. M.; Boquien, M.; Calzetti, D.; Combes, F.; Buchbender, C.; Braine, J.; Quintana-Lacaci, G.; Tabatabaei, F. S.; Lord, S.; Israel, F.; Stacey, G.; van der Werf, P.


    Within the framework of the HERM33ES Key Project (Kramer et al. 2010), using the high resolution and sensitivity of the Herschel photometric data, we study the compact emission in the Local Group spiral galaxy M 33. We present a catalogue of 159 compact emission sources in M 33 identified by SExtractor in the 250 μm SPIRE band which is the one that provides the best spatial resolution. We measure fluxes at 24 μm and Hα for those 159 extracted sources. We find a very strong Pearson correlation coefficient with the MIPS 24 μm emission (r24 = 0.94) and a rather strong correlation with the Hα emission, although with more scatter (rHα = 0.83). Due to the very strong link between the 250 μm compact emission and the 24 μm and Hα emissions, by recovering the star formation rate from standard recipes for H II regions, we are able to provide star formation rate calibrations based on the 250 μm compact emission alone. Finally, the morphological study of a set of three Hα shells shows that there is a displacement between far-ultraviolet and the SPIRE bands, while the Hα structure is in general much more coincident with the cool dust.

  12. A molecular outflow evidencing star formation activity in the vicinity of the HII region G034.8-0.7 and the SNR W44

    Paron, S; Rubio, M; Dubner, G


    This work aims at investigating the molecular gas component in the vicinity of two young stellar object (YSO) candidates identified at the border of the HII region G034.8-0.7 that is evolving within a molecular cloud shocked by the SNR W44. The purpose is to explore signatures of star forming activity in this complex region. We performed a near and mid infrared study towards the border of the HII region G034.8-0.7 and observed a 90" X 90" region near 18h 56m 48s, +01d 18' 45" (J2000) using the Atacama Submillimeter Telescope Experiment (ASTE) in the 12CO J=3--2, 13CO J=3--2, HCO+ J=4--3 and CS J=7--6 lines with an angular resolution of 22". Based on the infrared study we propose that the source 2MASS 18564827+0118471 (IR1 in this work) is a YSO candidate. We discovered a bipolar 12CO outflow in the direction of the line of sight and a HCO+ clump towards IR1, confirming that it is a YSO. From the detection of the CS J=7--6 line we infer the presence of high density (>10^7 cm^-3) and warm (>60 K) gas towards IR...

  13. Direct measurement of lensing amplification in Abell S1063 using a strongly lensed high redshift HII Galaxy

    Terlevich, Roberto; Terlevich, Elena; Chavez, Ricardo; Telles, Eduardo; Bresolin, Fabio; Plionis, Manolis; Basilakos, Spyros; Arenas, David Fernandez; Moran, Ana Luisa Gonzalez; Diaz, Angeles I; Aretxaga, Itziar


    ID11 is an actively star forming extremely compact galaxy and Ly alpha emitter at z=3.117 that is gravitationally magnified by a factor of ~17 by the cluster of galaxies Hubble Frontier Fields AS1063. Its observed properties resemble those of low luminosity HII galaxies or Giant HII regions like 30-Doradus in the LMC. Using the tight correlation correlation between the Balmer-line luminosities and the width of the emission lines (typically L(Hbeta)-sigma(Hbeta)) valid for HII galaxies and Giant HII regions to estimate its total luminosity, we are able to measure the lensing amplification of ID11. We obtain an amplification of 23 +- 11 similar within errors to the value of ~17 estimated or predicted by the best lensing models of the massive cluster Abell S1063. We also compiled from the literature luminosities and velocity dispersions for a set of lensed compact starforming regions. There is more scatter in the L-sigma correlation for these lensed systems but on the whole the results tend to support the lensin...

  14. The oxygen abundance in the inner HII regions of M101. Implications for the calibration of strong-line metallicity indicators

    Bresolin, F


    I present deep spectroscopy of four HII regions in the inner, metal-rich zone of the spiral galaxy M101 obtained with the LRIS spectrograph at the Keck telescope. From the analysis of the collisionally excited lines in two of the target HII regions, H1013 and H493, I have obtained oxygen abundances 12+log(O/H)=8.52 and 12+log(O/H)=8.74, respectively. These measurements extend the determination of the oxygen abundance gradient of M101 via the direct method to only 3 kpc from the center. The intensity of the CII 4267 line in H1013 leads to a carbon abundance 12+log(C/H)=8.66, corresponding to nearly twice the solar value. From a comparison of the continuum temperature derived from the Balmer discontinuity, T(Bac)=5000 K, and the line temperature derived from [OIII]4363/5007, T[OIII]=7700 K, an average temperature T0=5500 K and a mean square temperature fluctuation t^2=0.06 have been derived. Accounting for the spatial inhomogeneity in temperature raises the oxygen abundance obtained from the oxygen auroral line...

  15. The evolution of emission lines in HII galaxies

    Stasinska, G; Leitherer, C; Stasinska, Grazyna; Schaerer, Daniel; Leitherer, Claus


    We constructed diagnostic diagrams using emission line ratios and equivalent widths observed in several samples of HII galaxies. The diagrams are compared to predictions from new photoionization models for evolving starbursts. We find that HII galaxies from objective-prism surveys are not reproduced by models of instantaneous starbursts surrounded by constant density, ionization bounded HII regions. The observed relations between emission line ratios and Hb equivalent width (W(Hb)) can be understood if older stellar populations are not negligible in HII galaxies. Also, different dust obscuration for stars and gas and leakage of Lyman continuum photons from the observed HII regions can be important. As a result, HII galaxies selected from objective-prism surveys are unlikely to contain many objects in which the most recent starburst is older than about 5~Myr. The observed increase of [OI]/Hb with decreasing W(Hb) can result from the dynamical effects of winds and supernovae. This interpretation provides also a...

  16. The L-σ relation for HII galaxies in green

    Melnick, J.; Telles, E.; Bordalo, V.; Chávez, R.; Fernández-Arenas, D.; Terlevich, E.; Terlevich, R.; Bresolin, F.; Plionis, M.; Basilakos, S.


    The correlation between emission-line luminosity (L) and profile-width (σ) for HII galaxies provides a powerful method to measure the distances to galaxies over a wide range of redshifts. In this paper, we use SDSS spectrophotometry to explore the systematics of the correlation using the [OIII]5007 lines instead of Hα or Hβ to measure luminosities and line widths. We also examine possible systematic effects involved in measuring the profile-widths and the luminosities through different apertures. We find that the green L-σ relation, defined using [OIII]5007 luminosities, is significantly more sensitive than Hβ to the effects of age and the physical conditions of the nebulae, which more than offsets the advantage of the higher strength of the [OIII]5007 lines. We then explore the possibility of mixing [OIII]5007 profile-widths with SDSS Hβ luminosities using the Hubble constant H0 to quantify the possible systematic effects. We find the mixed L(Hβ) - σ[OIII] relation to be at least as powerful as the canonical L-σ relation as a distance estimator, and we show that evolutionary corrections do not change the slope and the scatter of the correlation and, therefore, do not bias the L-σ distance indicator at high redshifts. Locally, however, the luminosities of the giant HII regions that provide the zero-point calibrators are sensitive to evolutionary corrections and may bias the Hubble constant if their mean ages, as measured by the equivalent widths of Hβ, are significantly different from the mean age of the HII galaxies. Using a small sample of 16 ad-hoc zero point calibrators we obtain a value of H0 = 66.4+ 5.0-4.5km s-1 Mpc-1 for the Hubble constant, which is fully consistent with the best modern determinations, and which is not biased by evolutionary corrections.

  17. Stripped gas as fuel for newly formed HII regions in the encounter between VCC1249 and M49: a unified picture from NGVS and GUViCS

    Battaia, Fabrizio Arrigoni; Fumagalli, Michele; Boselli, Alessandro; Boissier, Samuel; Cortese, Luca; Heinis, Sebastien; Ferrarese, Laura; Côté, Patrick; Mihos, J Christopher; Cuillandre, Jean Charles; Duc, Pierre-Alain; Durrell, Patrick; Gwyn, Stephen; Jordán, Andrés; Liu, Chengze; Peng, Eric


    Context: We study the peculiar interacting galaxy system of VCC1249/M49 located in the core of the Virgo B subcluster. Owing to a recent interaction between the dwarf galaxy VCC1249 and the halo gas of the gE M49, neutral hydrogen has been displaced from the interstellar medium of this dwarf into the Virgo ICM. Observations also reveal multiple compact star-forming regions that are embedded in this HI cloud, with a projected separation up to 13 kpc from VCC1249 in the northwest direction. Aims: Motivated by recent NUV imaging from GUViCS of the VCC1249/M49 system that shows significant ongoing/recent star formation in the compact regions, we aim to constrain the origin of these outlying HII regions with a multi-wavelength approach. Methods: Using deep optical (u, g, i, z) imaging from NGVS and new Halpha imaging obtained at the San Pedro Martir observatory together with Keck long-slit spectroscopy, we characterize the SFR, ages, and metallicity of VCC1249 and its outlying compact regions. Moreover, we analyze...

  18. Photoionization models for giant h ii regions

    Gra´zyna Stasi´nska


    Full Text Available Revisamos las fuentes de incertidumbre en los modelos de fotoionizaci on de regiones H II gigantes. Tambi en discutimos el problema de la temperatura electr onica a la luz de los ajustes de modelos en tres regiones H II gigantes.

  19. Deep near-infrared adaptive optics observations of a young embedded cluster at the edge of the RCW 41 HII region

    Neichel, B; Plana, H; Zavagno, A; Bernard, A; Fusco, T


    We investigate the star formation activity in a young star forming cluster embedded at the edge of the RCW 41 HII region. As a complementary goal, we aim at demonstrating the gain provided by Wide-Field Adaptive Optics instruments to study young clusters. We used deep, JHKs images from the newly commissioned Gemini-GeMS/GSAOI instrument, complemented with Spitzer IRAC observations, in order to study the photometric properties of the young stellar cluster. GeMS is an AO instrument, delivering almost diffraction limited images over a field of 2' across. The exquisite angular resolution allows us to reach a limiting magnitude of J = 22 for 98% completeness. The combination of the IRAC photometry with our JHKs catalog is used to build color-color diagrams, and select Young Stellar Objects (YSOs) candidates. We detect the presence of 80 Young Stellar Object (YSO) candidates. Those YSOs are used to infer the cluster age, which is found to be in the range 1 to 5 Myr. We find that 1/3 of the YSOs are in a range betwe...

  20. An O2If*/WN6 Star Catch in the Act in a Compact Hii region in the Starburst Cluster NGC 3603

    Roman-Lopes, A


    In this paper I report the discovery of an O2If*/WN6 star probably still partially embedded in its parental cocoon in the star-burst cluster NGC 3603. From the observed size of the associated compact Hii region, it was possible to derive a probable dynamic age of no more than 600,000 years. Using the computed visual extinction value Av ~ 6 magnitudes, an absolute visual magnitude Mv =-5.7 mag is obtained, which for the assumed heliocentric distance of 7.6 kpc results in a bolometric luminosity of ~ 8x10^5 Lsun. Also from the V magnitude and the V-I color of the new star, and previous models for NGC3603's massive star population, we estimate its mass for the binary (O2If*/WN6 + O3If) and the single-star case (O2If*/WN6). In the former, it was found that the initial mass of each component possibly exceeded 80 Msun and 40 Msun, while in the latter MTT 58's initial mass possibly was in excess of 100 Msun.

  1. Modeling and predicting the shape of the far-infrared/submillimeter emission in ultra-compact HII regions and cold clumps

    Paradis, D; Noriega-Crespo, A; Paladini, R; Bernard, J -P; Bot, C; Cambrésy, L; Demyk, K; Gromov, V; Rivera-Ingraham, A; Veneziani, M


    Dust properties are likely affected by the environment in which dust grains evolve. For instance, some analyses of cold clumps (7 K- 17 K) lead to favor the aggregation process in dense environments. However, the study of warm (30 K-40 K) dust emission at long wavelength ($\\lambda$$>$300 $\\mu$m) has been limited by the difficulty in combining far infred-millimeter (FIR-mm) spectral coverage and high angular resolution to observe warm dust grains. Using Herschel data from 70 to 500 $\\mu$m, as part of the Herschel infrared Galactic (Hi-GAL) survey associated to 1.1 mm data from the Bolocam Galactic Plane Survey (BGPS), we compare emission in two types of environments: ultra-compact HII (UCHII) regions and cold molecular clumps (denoted as cold clumps). This comparison allows us to test models of dust emission in the FIR-mm domain used to reproduce emission in the diffuse medium, in these environments, and to check their ability to predict the dust emission in our Galaxy. We determine the emission spectra in twe...

  2. Extragalactic chemical abundances: do HII regions and young stars tell the same story? The case of the spiral galaxy NGC 300

    Bresolin, Fabio; Kudritzki, Rolf-Peter; Pietrzynski, Grzegorz; Urbaneja, Miguel A; Carraro, Giovanni


    (Abridged) We have obtained new spectrophotometric data for 28 HII regions in the spiral galaxy NGC 300, a member of the nearby Sculptor Group. The detection of auroral lines, including [OIII]4363, [SIII]6312 and [NII]5755, has allowed us to measure electron temperatures and direct chemical abundances for the whole sample. We determine for the first time in this galaxy a radial gas-phase oxygen abundance gradient based solely on auroral lines, and obtain the following least-square solution: 12+log(O/H)=8.57-0.41 R/R25, where the galactocentric distance is expressed in terms of the isophotal radius R25. The gradient corresponds to -0.077 dex/kpc, and agrees very well with the galactocentric trend in metallicity obtained for 29 B and A supergiants in the same galaxy. The intercept of the regression for the nebular data virtually coincides with the intercept obtained from the stellar data. This allows little room for depletion of nebular oxygen onto dust grains, although in this kind of comparison we are somewha...

  3. Giant Lipoma of Posterior Cervical Region

    Singh, Mahendra; Saxena, Ashish; Kumar, Lovekesh; Karande, Snehal K; Kolhe, Yuvraj


    ... on the extremities and trunk. However 13% of lipomas grow in the head and neck region [2]. Lipomas are usually small solitary lesions and rarely grow to an exceptionally large size. A lipoma is considered gi...

  4. Giant Broad Line Regions in Dwarf Seyferts

    Devereux, Nick


    High angular resolution spectroscopy obtained with the Hubble Space Telescope (HST) has revealed a remarkable population of galaxies hosting dwarf Seyfert nuclei with an unusually large broad-line region (BLR). These objects are remarkable for two reasons. Firstly, the size of the BLR can, in some cases, rival those seen in the most luminous quasars. Secondly, the size of the BLR is not correlated with the central continuum luminosity, an observation that distinguishes them from their reverberating counterparts. Collectively, these early results suggest that non-reverberating dwarf Seyferts are a heterogeneous group and not simply scaled versions of each other. Careful inspection reveals broad H Balmer emission lines with single peaks, double peaks, and a combination of the two, suggesting that the broad emission lines are produced in kinematically distinct regions centered on the black hole (BH). Because the gravitational field strength is already known for these objects, by virtue of knowing their BH mass, ...

  5. Giant Broad Line Regions in Dwarf Seyferts

    Nick Devereux


    High angular resolution spectroscopy obtained with the Hubble Space Telescope (HST) has revealed a remarkable population of galaxies hosting dwarf Seyfert nuclei with an unusually large broad-line region (BLR). These objects are remarkable for two reasons. Firstly, the size of the BLR can, in some cases, rival those seen in the most luminous quasars. Secondly, the size of the BLR is not correlated with the central continuum luminosity, an observation that distinguishes them from their reverberating counterparts. Collectively, these early results suggest that non-reverberating dwarf Seyferts are a heterogeneous group, and not simply scaled versions of each other. Careful inspection reveals broad H Balmer emission lines with single peaks, double peaks, and a combination of the two, suggesting that the broad emission lines are produced in kinematically distinct regions centered on the black hole (BH). Because the gravitational field strength is already known for these objects, by virtue of knowing their BH mass, the relationship between velocity and radius may be established, given a kinematic model for the BLR gas. In this way, one can determine the inner and outer radii of the BLRs by modeling the shape of their broad emission line profiles. In the present contribution, high quality spectra obtained with the Space Telescope Imaging Spectrograph (STIS) are used to constrain the size of the BLR in the dwarf Seyfert nuclei of M81, NGC 3998, NGC 4203, NGC 3227, NGC 4051 and NGC 3516.

  6. Gas Kinematics in the HII regions G351.69-1.15 and G351.63-1.25

    Veena, V S; Tej, A; Kantharia, N G; Ghosh, S K


    We probe the structure and kinematics of two neighbouring H II regions identified as cometary and bipolar, using radio recombination lines (RRL). The H172{\\alpha} RRLs from these H II regions: G351.6-1.15 and G351.6-1.25, are mapped using GMRT, India. We also detect carbon RRLs C172{\\alpha} towards both these regions. The hydrogen RRLs display the effects of pressure and dynamical broadening in the line profiles, with the dynamical broadening (15 km/s) playing a major role in the observed profile of G351.6-1.15. We investigate the kinematics of molecular gas species towards this H II region from the MALT90 pilot survey. The molecular gas is mostly distributed towards the north and north-west of the cometary head. The molecular line profiles indicate signatures of turbulence and outflow in this region. The ionized gas at the cometary tail is blue shifted by 8 km/s with respect to the ambient molecular cloud, consistent with the earlier proposed champagne flow scenario. The relative velocity of 5 km/s between t...

  7. First science results from SOFIA/FORCAST: The mid-infrared view of the compact HII region W3A

    Salgado, F; Adams, J D; Herter, T L; Gull, G; Schoenwald, J; Keller, L D; De Buizer, J M; Vacca, W D; Becklin, E E; Shuping, R Y; M., A G G; Tielens,; Zinnecker, H


    The massive star forming region W3 was observed with the faint object infrared camera for the SOFIA telescope (FORCAST) as part of the Short Science program. The 6.4, 6.6, 7.7, 19.7, 24.2, 31.5 and 37.1 \\um bandpasses were used to observe the emission of Polycyclic Aromatic Hydrocarbon (PAH) molecules, Very Small Grains and Big Grains. Optical depth and color temperature maps of W3A show that IRS2 has blown a bubble devoid of gas and dust of $\\sim$0.05 pc radius. It is embedded in a dusty shell of ionized gas that contributes 40% of the total 24 \\um emission of W3A. This dust component is mostly heated by far ultraviolet, rather than trapped Ly$\\alpha$ photons. This shell is itself surrounded by a thin ($\\sim$0.01 pc) photodissociation region where PAHs show intense emission. The infrared spectral energy distribution (SED) of three different zones located at 8, 20 and 25\\arcsec from IRS2, show that the peak of the SED shifts towards longer wavelengths, when moving away from the star. Adopting the stellar radi...

  8. Giant Birefringence of Lithium Niobate Crystals in the Terahertz Region

    SUN Yi-Min; MAO Zong-Liang; HOU Bi-Hui; LIU Guo-Qing; WANG Li


    Terahertz time-domain spectroscopy (THz-TDS) is used to study the spectral response of lithium niobate crystals (LiNbO3) in the far infrared region. The optical constants are derived from the measured complex refractive index.A giant birefringence is observed in this material, and the average refractive-index difference between the ordinary wave and the extraordinary wave, no - ne, can reach up to about 1.6. Such a large birefringence is attributed to the different phonon modes of A1 (z) and E(x, y). This unusual property makes LiNbO3 a promising material to be used as a functional material in the terahertz region, e.g. Employed as wave-plates and polarization separators.

  9. HII galaxies in 4D

    Telles, Eduardo


    HII galaxies are clumpy and their gas kinematics can be mapped to show the global turbulent motions and the effect of massive star evolution. The distribution of their physical conditions is homogeneous and oxygen abundance is uniform. The presence of nebular HeII 4868 line seems to be higher in a low abundance galaxy, implying a harder ionization power probably due to stars in low metallicity. Innovative methods of data cube analysis, namely PCA tomography (nicknamed 4D), seem promising in revealing additional information not detected with the standard methods. I review some of our own recent work on the 3D spectroscopy of HII galaxies.

  10. Habitat assessment for giant pandas in the Qinling Mountain region of China

    Feng, Tian-Tian; Van Manen, Frank T.; Zhao, Na-Xun; Li, Ming; Wei, Fu-Wen


    Because habitat loss and fragmentation threaten giant pandas (Ailuropoda melanoleuca), habitat protection and restoration are important conservation measures for this endangered species. However, distribution and value of potential habitat to giant pandas on a regional scale are not fully known. Therefore, we identified and ranked giant panda habitat in Foping Nature Reserve, Guanyinshan Nature Reserve, and adjacent areas in the Qinling Mountains of China. We used Mahalanobis distance and 11 digital habitat layers to develop a multivariate habitat signature associated with 247 surveyed giant panda locations, which we then applied to the study region. We identified approximately 128 km2 of giant panda habitat in Foping Nature Reserve (43.6% of the reserve) and 49 km2 in Guanyinshan Nature Reserve (33.6% of the reserve). We defined core habitat areas by incorporating a minimum patch-size criterion (5.5 km2) based on home-range size. Percentage of core habitat area was higher in Foping Nature Reserve (41.8% of the reserve) than Guanyinshan Nature Reserve (26.3% of the reserve). Within the larger analysis region, Foping Nature Reserve contained 32.7% of all core habitat areas we identified, indicating regional importance of the reserve. We observed a negative relationship between distribution of core areas and presence of roads and small villages. Protection of giant panda habitat at lower elevations and improvement of habitat linkages among core habitat areas are important in a regional approach to giant panda conservation.

  11. A Rare Case Report on Suboccipital Region Benign Giant Osteoma

    Bhattarai, Binod


    Herein we report a rare case of a giant suboccipital osteoma in a 55-year-old woman presenting primarily due to cosmetic issue. We discuss the management algorithm taken in the patient, highlighting excision of a potentially curable bony tumor only after ruling out its extension to the ear cavity, mastoid ear cells, transverse sinus, and the intracranial compartment. PMID:27051540

  12. The HII Galaxy Hubble Diagram Strongly Favors $R_{\\rm h}=ct$ over $\\Lambda$CDM

    Wei, Jun-Jie; Melia, Fulvio


    We continue to build support for the proposal to use HII galaxies (HIIGx) and giant extragalactic HII regions (GEHR) as standard candles to construct the Hubble diagram at redshifts beyond the current reach of Type Ia supernovae. Using a sample of 25 high-redshift HIIGx, 107 local HIIGx, and 24 GEHR, we confirm that the correlation between the emission-line luminosity and ionized-gas velocity dispersion is a viable luminosity indicator, and use it to test and compare the standard model $\\Lambda$CDM and the $R_{\\rm h}=ct$ Universe by optimizing the parameters in each cosmology using a maximization of the likelihood function. For the flat $\\Lambda$CDM model, the best fit is obtained with $\\Omega_{\\rm m}= 0.40_{-0.09}^{+0.09}$. However, statistical tools, such as the Akaike (AIC), Kullback (KIC) and Bayes (BIC) Information Criteria favor $R_{\\rm h}=ct$ over the standard model with a likelihood of $\\approx 94.8\\%-98.8\\%$ versus only $\\approx 1.2\\%-5.2\\%$. For $w$CDM (the version of $\\Lambda$CDM with a dark-energy...

  13. Molecular clouds associated with compact HII regionsin Galactic plane

    孙锦; 沈家健; 孙艳春; 张燕平


    13CO (J = 1 - 0) emission of massive star forming region including 15 ultracompact and 4compact HII regions in Galactic plane was mapped with the 13.7 m millimeter wave telescope of Purple Mountain Observatory. The present observations provide the first complete structure of the clouds in 13CO with a higher spatial resolution and a wide-field coverage of 28′×45′. Combined with the images of far-infrared emission and dust color temperature obtained from ISSA, various possible dynamical connections between the compact HII regions and associated clouds were found. We presente some reasons to explain the formation of new dense cold core and molecular emission cavity in the massive star formation and early evolution. The luminosities of excitation stars for all HII regions and the main parameters of associated clouds are also derived. The results show that the newborn stars' luminosities are correlated with the 13CO column densities, masses (in 55"beam) and 13CO velocity widths obviously.``

  14. HeI in the central Giant HII Region of NGC 5253. A 2D observational approach to collisional and radiative transfer effects

    Monreal-Ibero, Ana; Westmoquette, Mark S; Vilchez, Jose M


    ABRIDGED: NGC5253 is an ideal laboratory for detailed studies of starburst galaxies. We present for the first in a starburst galaxy a 2D study of the spatial behavior of collisional and radiative transfer effects in He^+. The HeI lines are analysed based on data obtained with FLAMES and GMOS. Collisional effects are negligible (i.e. 0.1-0.6%) for transitions in the singlet cascade while relatively important for those in the triplet cascade. In particular, they can contribute up to 20% of the flux in the HeIl7065 line. Radiative transfer effects are important over an extended and circular area of 30pc in diameter centered at the Super Star Clusters. HeI abundance, y^+, has been mapped using extinction corrected fluxes of six HeI lines, realistic assumptions for T_e, n_e, and the stellar absorption equivalent width as well as the most recent emissivities. We found a mean of 10^3 y^+ ~81.6 over the mapped area. The relation between the excitation and the total helium abundance, y_tot, is consistent with no abund...


    A. Torres-Campos


    Full Text Available Usando im genes en los filtros H y [OIII] h5007 tomadas con el telescopio SOAR de 4.1 m hemos creado un cat logo de regiones HII en las galaxias HII Tol 1358-328 y Mrk 1318. Este cat logo es el primer paso de un trabajo que pretende caracterizar la formaci n estelar y el impacto que tiene en el medio interestelar (MIE que lo rodea en galaxias HII extremadamente j venes.

  16. Mäesuitsu hiis / Ahto Kaasik

    Kaasik, Ahto, 1969-


    Tartumaal Võnnu vallas Terikese külas asuvast Mäesuitsu hiiest, mida on nimetatud ka Suitsumäe hiis, Suitsumägi, Salumägi, Härja hiie mägi, Ohvrimägi, Ohvrimäe hiis, Ukumägi ning taluomaniku järgi ka Ääre-, Ääru- ja Ääro mägi

  17. Quantifying landscape linkages among giant panda subpopulations in regional scale conservation.

    Qi, Dunwu; Hu, Yibo; Gu, Xiaodong; Yang, Xuyi; Yang, Guang; Wei, Fuwen


    Understanding habitat requirements and identifying landscape linkages are essential for the survival of isolated populations of endangered species. Currently, some of the giant panda populations are isolated, which threatens their long-term survival, particularly in the Xiaoxiangling mountains. In the present study, we quantified niche requirements and then identified potential linkages of giant panda subpopulations in the most isolated region, using ecological niche factor analysis and a least-cost path model. Giant pandas preferred habitat with conifer forest and gentle slopes (>20 to ≤30°). Based on spatial distribution of suitable habitat, linkages were identified for the Yele subpopulation to 4 other subpopulations (Liziping, Matou, Xinmin and Wanba). Their lengths ranged from 15 to 54 km. The accumulated cost ranged from 693 to 3166 and conifer forest covered over 31%. However, a variety of features (e.g. major roads, human settlements and large unforested areas) might act as barriers along the linkages for giant panda dispersal. Our analysis quantified giant panda subpopulation connectivity to ensure long-term survival.

  18. On the compact HII galaxy UM 408 as seen by GMOS-IFU: Physical conditions

    Lagos, Patricio; Munoz-Tunon, Casiana; Carrasco, Eleazar R; Cuisinier, Francois; Tenorio-Tagle, Guillermo


    We present Integral Field Unit GMOS-IFU data of the compact HII galaxy UM408, obtained at Gemini South telescope, in order to derive the spatial distribution of emission lines and line ratios, kinematics, plasma parameters, and oxygen abundances as well the integrated properties over an area of 3"x4".4(~750x1100 pc) located in the central part of the galaxy. The starburst in this area is resolved into two giant regions of ~375 and 250pc diameter, respectively. The ages of these two regions, estimated using Hb equivalent widths, suggest that they are coeval events of ~5Myr with stellar masses of ~10^4M_o. We have also used [OIII]/Hb and [SII]/Ha ratio maps to explore the excitation mechanisms in this galaxy. The Ha emission line was used to measure the radial velocity and velocity dispersion. We derived an integrated oxygen abundance of 12+log(O/H)=7.87 summing over all spaxels in our field of view. An average value of 12+log(O/H)=7.77 and a difference of D(O/H)=0.47 between the minimum and maximum values (7.5...

  19. Pluto's elongated dark regions formed by the Charon-forming giant impact

    Genda, Hidenori; Sekine, Yusuhito; Kamata, Shunichi; Funatsu, Taro


    The New Horizons spacecraft has found elongated dark areas in the equatorial region of Pluto, which were informally called "the Whale" or Cthulhu Region (Stern et al. 2015). Here we examine the possibility that the dark areas on Pluto were formed by thermal alterations and polymerization of interstellar volatiles caused by a Charon-forming giant impact. Pluto is one of the largest Kuiper belt objects, which is highly likely to contain various interstellar volatiles, including aldehyde and ammonia. The previous study (Cordy et al. 2011) shows that these interstellar volatiles are thermally polymerized in solutions at high temperatures, forming complex insoluble organic solids. Given the satellite-to-planet mass ratio, the Pluto-Charon system is suggested to be of a giant impact origin (Canup 2005). Impact-induced heating on Pluto could have converted these volatile into complex organic matter in solution near the surface, which may explain the presence of dark areas in the equatorial region of Pluto. Here, we produce complex organic matter for various temperatures by thermal polymerization of formaldehyde and ammonia in solutions. By measuring the UV-VIS absorption spectra of the produced organic matter, we found that the color of the solution changes to be dark if the temerature is above 50 degree C for months or more. This duration corresponds to the cooling timescale of a water pond with 500-km thickness. By using SPH code (Genda et al. 2015), we carried out many simulations of a giant impact, and we found that a molten hot pond with > 500-km thickness is formed around the equatorial region of Pluto by a Charon-forming giant impact, if the water/rock mixing mass ratio is less than 1 or if the pre-impact interior temperature is 150 K. Both the dark equatorial region and a Charon-sized moon are formed when the pre-impact Pluto is undifferentiated. To keep a rock-rich Pluto undifferentiated at time of the giant impact, Pluto may have been formed >100 Myrs after CAIs

  20. Mid-Infrared diagnostics of metal-rich HII regions from VLT and Spitzer Spectroscopy of Young Massive Stars in W31

    Furness, JP; Morris, PW; Barbosa, CL; Blum, RD; Conti, PS; van Dyk, SD


    We present near-IR VLT/ISAAC and mid-IR Spitzer/IRS spectroscopy of the young massive cluster in the W31 star-forming region. H-band spectroscopy provides refined classifications for four cluster members O stars with respect to Blum et al. In addition, photospheric features are detected in the massive Young Stellar Object (mYSO) #26. Spectroscopy permits estimates of stellar temperatures and masses, from which a cluster age of ~0.6 Myr and distance of 3.3 kpc are obtained, in excellent agreement with Blum et al. IRS spectroscopy reveals mid-infrared fine structure line fluxes of [Ne II-III] and [S III-IV] for four O stars and five mYSOs. In common with previous studies, stellar temperatures of individual stars are severely underestimated from the observed ratios of fine-structure lines, despite the use of contemporary stellar atmosphere and photoionization models. We construct empirical temperature calibrations based upon the W31 cluster stars of known spectral type, supplemented by two inner Milky Way ultrac...

  1. The Charon-forming giant impact as a source of Pluto's dark equatorial regions

    Sekine, Yasuhito; Genda, Hidenori; Kamata, Shunichi; Funatsu, Taro


    Pluto exhibits complex regional diversity in its surface materials 1,2 . One of the most striking features is the dark reddish material, possibly organic matter, along Pluto's equator coexisting with the H2O-rich crust 2 . Little is known, however, about the surface process responsible for the dark equatorial regions. Here, we propose that Pluto's dark regions were formed through reactions in elongated pools of liquid water near the equator, generated by the giant impact that formed Charon 3-5 . Our laboratory experiments show that dark reddish organic matter, comparable to Pluto's dark materials, is produced through polymerization of simple organic compounds 6,7 that would have been present in proto-Pluto (for example, formaldehyde) by prolonged heating at temperatures ≥50 °C. Through hydrodynamic impact simulations, we demonstrate that an impactor, one-third the mass of Pluto, colliding with proto-Pluto—with an interior potential temperature of 150-200 K—could have generated both a Charon-sized satellite and high-temperature regions around Pluto's equator. We also propose that high-velocity giant impacts result in global or hemispherical darkening and reddening, suggesting that the colour variety of large Kuiper belt objects 8-12 could have been caused by frequent, stochastic giant impacts in a massive outer protoplanetary disk in the early Solar System 13-16 .

  2. Cosmological HII Bubble Growth During Reionization

    Shin, Min-Su; Cen, Renyue


    We present general properties of ionized hydrogen (HII) bubbles and their growth based on a state-of-the-art large-scale (100 Mpc/h) cosmological radiative transfer simulation. The simulation resolves all halos with atomic cooling at the relevant redshifts and simultaneously performs radiative transfer and dynamical evolution of structure formation. Our major conclusions include: (1) for significant HII bubbles, the number distribution is peaked at a volume of ~ 0.6 Mpc^3/h^3 at all redshifts. But, at z 10 even the largest HII bubbles have a balanced ionizing photon contribution from Pop II and Pop III stars, while at z < 8 Pop II stars start to dominate the overall ionizing photon production for large bubbles, although Pop III stars continue to make a non-negligible contribution. (6) The relationship between halo number density and bubble size is complicated but a strong correlation is found between halo number density and bubble size for for large bubbles.

  3. Movement anatomy of the gluteal region and thigh of the giant anteater Myrmecophaga tridactyla (Myrmecophagidae: Pilosa

    Priscilla Rosa Queiroz Ribeiro


    Full Text Available Abstract: Locomotion reveals the displacement and behavior manner of the species in their daily needs. According to different needs of the several species, different locomotor patterns are adopted. The shapes and attachment points of muscles are important determinants of the movements performed and consequently, the locomotion and motion patterns of living beings. It was aimed to associate anatomical, kinesiology and biomechanics aspects of the gluteal region and thigh of the giant anteater to its moving characteristics and locomotor habits. It was used three specimens of Myrmecophaga tridactyla, settled in formaldehyde aqueous solution at 10% and subsequently, dissected using usual techniques in gross anatomy. The morphological characteristics of the gluteal region and thigh that influence the patterns of movement and locomotion of animals, were analyzed and discussed in light of literature. All muscles of the gluteal region and thigh of giant anteater show parallel arrangement of the muscular fibers, being flat or fusiform. These muscles are formed in the joint which the interpotent type biolever act. These morphological characteristics indicate a greater predominance of amplitude and movement speed at the expense of strength. On the other hand, features such as osteometric index and the observation of giant anteater motion indicate the opposite, what reflects this animal lack of expertise in locomotor habits and shows the need of future realization of more detailed studies in this subject.


    E. Telles


    Full Text Available In this contribution I will very brie y summarize some recent results obtained applying 3D spectroscopy to observations of the well known HII galaxy II Zw 40, both in the optical and near-IR. I have studied the distribution of the dust in the starburst region, the velocity and velocity dispersion, and the geometry of the molecular hydrogen and ionized gas. I found a clear correlation between the component of the ISM and the velocity eld suggesting that the latter has a fundamental role in de ning the modes of the star formation process.

  5. Giant flux jumps through a thin superconducting Nb film in a vortex free region

    Tsindlekht, M.I., E-mail: [The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Genkin, V.M.; Felner, I.; Zeides, F.; Katz, N. [The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Gazi, Š.; Chromik, Š. [The Institute of Electrical Engineering SAS, Dúbravská cesta 9, 84104 Bratislava (Slovakia)


    Highlights: Giant magnetic flux jumps into thin-walled cylinder were measured using peak up coil method in a swept magnetic field. Magnetic moment jumps were observed in magnetic fields lower and above Hc1. - Abstract: We measure the dynamics of magnetic field penetration into thin-walled superconducting niobium cylinders. It is shown that magnetic field penetrates through the wall of a cylinder in a series of giant jumps with amplitude 1 - 2 mT and duration of less than a microsecond in a wide range of magnetic fields, including the vortex free region. Surprisingly, the jumps take place when the total current in the wall, not the current density, exceeds a critical value. In addition, there are small jumps and/or smooth penetration, but their contribution reaches only ≃ 20 % of the total penetrating flux. The number of jumps decreases with increased temperature. Thermomagnetic instabilities cannot explain the experimental observations.

  6. Different structures formed at HII boundaries

    Miao, Jingqi; Cornwall, Paul; Kinnear, Tim


    Hydrodynamic simulations on the evolution of molecular clouds (MCs) at HII boundaries are used to show that radiation driven implosion (RDI) model can create almost all of the different morphological structures, such as a single bright-rimmed cloud (BRC), fragment structure and multiple elephant trunk (ET) structures.

  7. Giant panda BAC library construction and assembly of a 650-kb contig spanning major histocompatibility complex class II region

    Pan Hui-Juan


    Full Text Available Abstract Background Giant panda is rare and endangered species endemic to China. The low rates of reproductive success and infectious disease resistance have severely hampered the development of captive and wild populations of the giant panda. The major histocompatibility complex (MHC plays important roles in immune response and reproductive system such as mate choice and mother-fetus bio-compatibility. It is thus essential to understand genetic details of the giant panda MHC. Construction of a bacterial artificial chromosome (BAC library will provide a new tool for panda genome physical mapping and thus facilitate understanding of panda MHC genes. Results A giant panda BAC library consisting of 205,800 clones has been constructed. The average insert size was calculated to be 97 kb based on the examination of 174 randomly selected clones, indicating that the giant panda library contained 6.8-fold genome equivalents. Screening of the library with 16 giant panda PCR primer pairs revealed 6.4 positive clones per locus, in good agreement with an expected 6.8-fold genomic coverage of the library. Based on this BAC library, we constructed a contig map of the giant panda MHC class II region from BTNL2 to DAXX spanning about 650 kb by a three-step method: (1 PCR-based screening of the BAC library with primers from homologous MHC class II gene loci, end sequences and BAC clone shotgun sequences, (2 DNA sequencing validation of positive clones, and (3 restriction digest fingerprinting verification of inter-clone overlapping. Conclusion The identifications of genes and genomic regions of interest are greatly favored by the availability of this giant panda BAC library. The giant panda BAC library thus provides a useful platform for physical mapping, genome sequencing or complex analysis of targeted genomic regions. The 650 kb sequence-ready BAC contig map of the giant panda MHC class II region from BTNL2 to DAXX, verified by the three-step method, offers a

  8. Eventful Evolution of Giant Molecular Clouds in Dynamically Evolving Spiral Arms

    Baba, Junichi; Morokuma-Matsui, Kana; Saitoh, Takayuki R.


    The formation and evolution of giant molecular clouds (GMCs) in spiral galaxies have been investigated in the traditional framework of the combined quasi-stationary density wave and galactic shock model. In this study, we investigate the structure and evolution of GMCs in a dynamically evolving spiral arm using a three-dimensional N-body/hydrodynamic simulation of a barred spiral galaxy at parsec-scale resolution. This simulation incorporated self-gravity, molecular hydrogen formation, radiative cooling, heating due to interstellar far-ultraviolet radiation, and stellar feedback by both HII regions and Type-II supernovae. In contrast to a simple expectation based on the traditional spiral model, the GMCs exhibited no systematic evolutionary sequence across the spiral arm. Our simulation showed that the GMCs behaved as highly dynamic objects with eventful lives involving collisional build-up, collision-induced star formation, and destruction via stellar feedback. The GMC lifetimes were predicted to be short, only a few tens of millions years. We also found that, at least at the resolutions and with the feedback models used in this study, most of the GMCs without HII regions were collapsing, but half of the GMCs with HII regions were expanding owing to the HII-region feedback from stars within them. Our results support the dynamic and feedback-regulated GMC evolution scenario. Although the simulated GMCs were converging rather than virial equilibrium, they followed the observed scaling relationship well. We also analysed the effects of galactic tides and external pressure on GMC evolution and suggested that GMCs cannot be regarded as isolated systems since their evolution in disc galaxies is complicated because of these environmental effects.

  9. Clinical study on CyberKnife for treating giant cavernous hemangioma in cavernous sinus region

    Lu SUN


    Full Text Available Objective To investigate the efficacy and safety of CyberKnife for giant cavernous hemangioma in cavernous sinus. Methods The data of 7 cases of giant cavernous hemangioma in cavernous sinus region confirmed by imaging examination and treated with CyberKnife were collected. The tumor volume was 11.86-70.12 cm3 (median 23.30 cm3. CT and MRI were acquired and fused by MIM 6.5.4 software. The acquired data sets were imported into a CyberKnife Robotic Radiosurgery System (Multiplan 4.0.2 and used to delineate the target organs at risk. The irradiation doses received by the lesions were 21 Gy/3 times in 5 cases, 25 Gy/5 times in one case and 30 Gy/3 times in one case. The exposure field was 109-155, and target volume reached over 95%. Patients maintained at supine positionduring treatment and utilized a 6D-skull trace mode specific to CyberKnife. Changes of clinical symptoms and imaging immediately after treatment and during follow-up period were observed to evaluate the efficacy and safety of this therapeutic method. Results Patients were followed-up for 6-18 months, and the meanfollow-up period was 9.37 months. Volumes of lesions were calculated after operation. All of these patients showed decrease in tumor volume (35.48% to 84.03% and improvement in symptoms (including visual impairment, visual field defect and headaches after therapy. Postoperative MRI revealed the tumor volume was 6.75-28.35 cm3 (median 10.50 cm3, which were significantly lower than that of before treatment [11.86-70.12 cm3 (median 23.30 cm3; Z = -2.366, P = 0.018]. Only one case presented radioactive cerebral edema, and the symptom was disappeared after 5-day treatment with mannitol and dexamethasone. Conclusions CyberKnife is an effective treatment method for giant cavernous hemangioma in cavernous sinus region. It is suggested to be the first selection for patients with giant cavernous hemangioma in cavernous sinus, who are not suitable for traditional surgeries and general

  10. A kinematic analysis of the Giant star-forming Region of N11

    Torres-Flores, Sergio; Barbá, Rodolfo; Maíz Apellániz, Jesús; Rubio, Mónica; Bosch, Guillermo


    In this work we present high resolution spectroscopic data of the giant star-forming region of N11, obtained with the GIRAFFE instrument at the Very Large Telescope. By using this data set, we find that most of the Hα emission lines profiles in this complex can be fitted by a single Gaussian, however, multiple emission line profiles can be observed in the central region of N11. By adding all the spectra, we derive the integrated Hα profile of this complex, which displays a width (σ) of about 12 km s-1 (corrected by instrumental and thermal width). We find that a single Gaussian fit on the integrated Hα profile leaves remaining wings, which can be fitted by a secondary broad Gaussian component. In addition, we find high velocity features, which spatially correlate with soft diffuse X-ray emission.

  11. On the Onset of Secondary Stellar Generations in Giant Star Forming Regions and Massive Star Clusters

    Palouš, Jan; Tenorio-Tagle, Guillermo


    Here we consider the strong evolution experienced by the matter reinserted by massive stars, both in giant star forming regions driven by a constant star formation rate, and in massive and coeval superstar clusters. In both cases we take into consideration the changes induced by stellar evolution on the number of massive stars, the number of ionizing photons and the integrated mechanical luminosity of the star forming regions. The latter is at all times compared with the critical luminosity that defines, for a given size, the lower mechanical luminosity limit above which the matter reinserted via strong winds and supernova explosions suffers frequent and recurrent thermal instabilities that reduce its temperature and pressure and inhibit its exit as part of a global wind. Instead, the unstable reinserted matter is compressed by the pervasive hot gas, and photoionization maintains its temperature at T $\\sim$ 10$^4$ K. As the evolution proceeds, more unstable matter accumulates and the unstable clumps grow in s...

  12. A kinematic analysis of the Giant star-forming Region of N11

    Torres-Flores, S; Apellániz, J Maíz; Rubio, M; Bosch, G


    In this work we present high resolution spectroscopic data of the giant star-forming region of N11, obtained with the GIRAFFE instrument at the Very Large Telescope. By using this data set, we find that most of the H$\\alpha$ emission lines profiles in this complex can be fitted by a single Gaussian, however, multiple emission line profiles can be observed in the central region of N11. By adding all the spectra, we derive the integrated H$\\alpha$ profile of this complex, which displays a width ($\\sigma$) of about 12 km s$^{-1}$ (corrected by instrumental and thermal width). We find that a single Gaussian fit on the integrated H$\\alpha$ profile leaves remaining wings, which can be fitted by a secondary broad Gaussian component. In addition, we find high velocity features, which spatially correlate with soft diffuse X-ray emission.

  13. Effects of Conservation Policies on Forest Cover Change in Giant Panda Habitat Regions, China.

    Li, Yu; Viña, Andrés; Yang, Wu; Chen, Xiaodong; Zhang, Jindong; Ouyang, Zhiyun; Liang, Zai; Liu, Jianguo


    After long periods of deforestation, forest transition has occurred globally, but the causes of forest transition in different countries are highly variable. Conservation policies may play important roles in facilitating forest transition around the world, including China. To restore forests and protect the remaining natural forests, the Chinese government initiated two nationwide conservation policies in the late 1990s -- the Natural Forest Conservation Program (NFCP) and the Grain-To-Green Program (GTGP). While some studies have discussed the environmental and socioeconomic effects of each of these policies independently and others have attributed forest recovery to both policies without rigorous and quantitative analysis, it is necessary to rigorously quantify the outcomes of these two conservation policies simultaneously because the two policies have been implemented at the same time. To fill the knowledge gap, this study quantitatively evaluated the effects of the two conservation policies on forest cover change between 2001 and 2008 in 108 townships located in two important giant panda habitat regions -- the Qinling Mountains region in Shaanxi Province and the Sichuan Giant Panda Sanctuary in Sichuan Province. Forest cover change was evaluated using a land-cover product (MCD12Q1) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). This product proved to be highly accurate in the study region (overall accuracy was ca. 87%, using 425 ground truth points collected in the field), thus suitable for the forest change analysis performed. Results showed that within the timeframe evaluated, most townships in both regions exhibited either increases or no changes in forest cover. After accounting for a variety of socioeconomic and biophysical attributes, an Ordinary Least Square (OLS) regression model suggests that the two policies had statistically significant positive effects on forest cover change after seven years of implementation, while

  14. A kinematic study of the giant star-forming region 30 Doradus

    Torres-Flores, Sergio; Apellániz, Jesús Maíz; Rubio, Mónica; Bosch, Guillermo


    We present, for the first time, an optical spectroscopic data cube of the giant star-forming region 30 Doradus, obtained with the GIRAFFE on the VLT at Paranal Observatory. The main emission lines present in this data cube correspond to H{\\alpha}, [NII] 6548 {\\AA} and [NII] 6584 {\\AA}. By using this data set, we found that H{\\alpha} presents from simple to multiple profiles, which suggests that different physical mechanisms act in different ways on the excited gas in 30 Doradus. We found, at least, three unclassified large expanding structures. These structures correlate with peaks in the X-ray distribution. Given the excellent signal-to-noise ratio and the large spatial coverage of this data cube, we have studied in detail the kinematics of 30 Doradus, showing the importance of the small scale phenomena on the integrated properties of 30 Doradus.

  15. Novel duplication pattern of the mitochondrial control region in Cantor's Giant softshell turtle Pelochelys cantorii.

    Zhang, Xin-Cheng; Li, Wei; Zhao, Jian; Chen, Hai-Gang; Zhu, Xin-Ping


    Cantor's Giant Softshell Turtle, Pelochelys cantorii has become one of the most critically endangered species in the world. When comparative analyses of the P. cantorii complete mitochondrial genome sequences were conducted, we discovered a duplication of a segment of the control region in the mitochondrial genome of P. cantorii. The duplication is characterized by two copies of conserved sequence box 2 (CSB2) and CSB3 in a single control region. In contrast to previous reports of duplications involving the control regions of other animals, this particular pattern of duplications appears to be unique to P. cantorii. Copies of the CSB2 and CSB3 show many of the conserved sequence features typically found in mitochondrial control regions, and rare differences were found between the paralogous copies. Using the primer design principle of simple sequence repeats (SSR) and the reference sequence of the duplicated CSBs, specific primers were designed to amplify the duplicated CSBs. These primers were validated among different individuals and populations of P. cantorii. This unique duplication structure suggests the two copies of the CSB2 and CSB3 may have arisen through occasional tandem duplication and subsequent concerted evolution.

  16. Studying the kinematics of the giant star-forming region 30 Doradus. I. The data

    Torres-Flores, S; Apellániz, J Maíz; Rubio, M; Bosch, G; Hénault-Brunet, V; Evans, C J


    We present high-quality VLT-FLAMES optical spectroscopy of the nebular gas in the giant star-forming region 30 Doradus. In this paper, the first of a series, we introduce our observations and discuss the main kinematic features of 30 Dor, as revealed by the spectroscopy of the ionized gas in the region. The primary data set consists of regular grid of nebular observations, which we used to produce a spectroscopic datacube of 30 Dor, centered on the massive star cluster R136 and covering a field-of-view of 10'x10'. The main emission lines present in the datacube are from Halpha and [NII]6548,6584. The Halpha emission-line profile varies across the region from simple single-peaked emission to complex, multiple-component profiles, suggesting that different physical mechanisms are acting on the excited gas. To analyse the gas kinematics we fit Gaussian profiles to the observed Halpha features. Unexpectedly, the narrowest Halpha profile in our sample lies close to the supernova remnant 30 Dor B. We present maps of...


    Cecco, Alessandra Di [INAF-Osservatorio Astronomico di Teramo, Via Mentore Maggini snc, I-64100 Teramo (Italy); Faustini, Fabiana; Calzoletti, Luca [ASDC-ASI Science Data Center, Via G. Galilei snc, I-00044 Frascati (RM) (Italy); Paresce, Francesco [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Via Piero Gobetti 101, I-40129 Bologna (Italy); Correnti, Matteo, E-mail: [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)


    We observed the giant H II region around the NGC 3603 YC with the five broad bands (70, 160, 250, 350, 500 μm) of the SPIRE and PACS instruments, on board the Herschel Space Observatory. Together with what is currently known of the stellar, atomic, molecular, and warm dust components, this additional and crucial information should allow us to better understand the details of the star-formation history in this region. The main objective of the investigation is to study, at high spatial resolution, the distribution and main physical characteristics of the cold dust. By reconstructing the temperature and density maps, we found, respectively, a mean value of 36 K and log{sub 10} N {sub H} = 22.0 ± 0.1 cm{sup –2}. We carried out a photometric analysis detecting 107 point-like sources, mostly confined to the north and south of the cluster. By comparing our data with spectral energy distribution models, we found that 35 sources are well represented by young stellar objects in early evolutionary phases, from Class 0 to Class I. The Herschel detections also provided far-IR counterparts for 4 H{sub 2}O masers and 11 objects previously known from mid-IR observations. The existence of so many embedded sources confirms the hypothesis of intense and ongoing star-formation activity in the region around NGC 3603 YC.

  18. Starburst in the interacting HII galaxy II Zw 40 and in non-interacting HII galaxies

    Telles, Eduardo


    I summarize the results of our integral field spectroscopic observations of the nearby prototype of HII galaxies, II Zw 40. Observations with GMOS-IFU on GEMINI-North in the optical allowed us to make a detailed kinematic picture of the central starburst, while SINFONI with adaptive optics on the ESO-VLT gave us a near-IR view of the interplay between the ISM phases. Here, I also address the question that not all starbursts require an external trigger such as a galaxy-galaxy encounter, as it seems to be the case for a fraction of low luminosity HII galaxies. We speculate that these may form stars spontaneously like "pop-corn in a pan".

  19. LABOCA observations of giant molecular clouds in the south west region of the Small Magellanic Cloud

    Bot, Caroline; Boulanger, Francois; Albrecht, Marcus; Leroy, Adam; Bolatto, Alberto D; Bertoldi, Frank; Gordon, Karl; Engelbracht, Chad; Block, Miwa; Misselt, Karl


    The amount of molecular gas is a key for understanding the future star formation in a galaxy. Because H2 is difficult to observe directly in dense and cold clouds, tracers like CO are used. However, at low metallicities especially, CO only traces the shielded interiors of the clouds. mm dust emission can be used as a tracer to unveil the total dense gas masses. The comparison of masses deduced from the continuum SIMBA 1.2 mm emission and virial masses in a sample of giant molecular clouds (GMCs), in the SW region of the Small Magellanic Cloud (SMC), showed a discrepancy that is in need of an explanation. This study aims at better assessing possible uncertainties on the dust emission observed in the sample of GMCs from the SMC and focuses on the densest parts of the GMCs where CO is detected. New observations were obtained with the LABOCA camera on the APEX telescope. All GMCs previously observed in CO are detected and their emission at 870microns is compared to ancillary data. The different contributions to t...

  20. Coeval giant landslides in the Canary Islands: Implications for global, regional and local triggers of giant flank collapses on oceanic volcanoes

    Boulesteix, Thomas; Hildenbrand, Anthony; Soler, Vicente; Quidelleur, Xavier; Gillot, Pierre-Yves


    Giant landslides are an important part of the evolution of most intra-plate volcanic islands. They often proceed in catastrophic events, likely to generate voluminous debris avalanches and eventually trigger destructive tsunamis. Although knowledge of the timing of their recurrence is a key factor regarding the hazard assessment in coastal environments, only a few of them have been well dated. In this contribution, we focus on the La Orotava event on Tenerife, which we date with the unspiked K-Ar technique, between 534 and 523 ka. Such narrow temporal interval is compatible, within uncertainties, with the age of the Cumbre Nueva collapse on the neighboring island of La Palma. We thus examine here the possible common triggering mechanisms at the global, regional and local scales. Both events occurred shortly after the climax of the oxygen isotopic stage 14, during the rapid transition towards the interglacial stage 13, reinforcing the hypothesis of a control from global paleoclimatic changes on the destabilization of oceanic islands. Intense volcanic pulses at the regional scale also lead to the synchronous overgrowth of several volcanic islands in the archipelago, but coeval destabilization on Tenerife and La Palma appears significantly controlled by the intrinsic morphology of the edifices, with contrasted instability thresholds for shield volcanoes and volcanic ridges respectively. Finally, we propose that the two events may be genetically linked. Dynamic transfer of voluminous debris avalanches during a giant landslide episode can induce isostatic readjustments, generate significant ground acceleration and finally produce a large tsunami, three processes which can concur to trigger large scale flank collapse on a neighboring mature unstable volcanic island.

  1. The Radio Properties of Composite LINER/HII Galaxies

    Filho, M E; Ho, L C; Filho, Mercedes E.; Barthel, Peter D.; Ho, Luis C.


    Arcsec-resolution VLA observations -- newly obtained as well as published -- of 40 nearby galaxies are discussed, completing a study of the radio properties of a magnitude-limited sample of nearby galaxies of the composite LINER/HII type. Our results reveal an overall detection rate of at least 25% AGN candidates among these composite sources. The general properties of these AGN candidates, as compared to non-AGN composite sources and HII galaxies, are discussed.

  2. Giant magmatic water reservoir beneath Uturuncu volcano and Altiplano-Puna region (Central Andes)

    Laumonier, Mickael; Gaillard, Fabrice; Muir, Duncan; Blundy, Jon; Unsworth, Martyn


    Volcanism at continental arcs is the surface manifestation of long-lived crustal magmatic processes whereby mantle-derived hydrous basalt magma differentiates to more silica-rich magmas by a combination of crystallization and crustal melting. What erupts is just a fraction of the total volume of magma produced by these processes; the unerupted, plutonic residues solidify and are inaccessible to direct study until millions of years of uplift and erosion bring them to the surface. In contrast, geophysical surveys, using electromagnetic and seismic waves, can provide real-time images of subduction zone magmatic systems. Several such studies have revealed that arc volcanoes are underlain by large partially molten regions at depths of >10 km, the largest known example being the Altiplano-Puna magma body (APMB) in central Andes. Interpreting such geophysical images in terms of amount, composition and distribution of partial melts is limited by our lack of knowledge of the physical properties of silicate melts at elevated pressures and temperatures. Here we present high-pressure, in situ experimental data showing that the electrical conductivity of andesitic melts is primarily controlled by their dissolved water contents. Linking our new measurements to petrological constraints from andesites erupted on the Altiplano, we show that the APMB is composed of 10-20% of an andesitic melt containing 8-10 wt% dissolved water. This implies that the APMB is a giant water anomaly in the global subduction system, with a total mass of dissolved magmatic water about half of the water contained within the Adriatic Sea. In addition to the controls on the physical properties of the melts, the abundance of dissolved water governs the structural levels of magma ponding, equivalent to the depth of water saturation, where degassing and crystallisation promote partial melting and weakening of the upper crust. Unexpectedly, very high concentrations of water in andesite magmas shall impede their

  3. Doppler Imaging of Young Late-Type Stars: HII 686, HII 3163, and P1724

    Stout-Batalha, Natalie Marie

    Maximum entropy image reconstruction (Doppler imaging) is applied to HII 686 (K4V, v sin i=64 km s-1) and HII 3163 (K0, v sin i=70 km s-1), two zero-age main sequence stars of the Pleiades cluster, and the weak-lined T Tauri star Parenago 1724 (K0, v sin i=71 km s-1). Their surface temperature distributions are determined in order to study the nature of magnetic activity in young ultra-fast rotators. Specific intensity line profiles used in the DI algorithm are synthesized. The sensitivity of the reconstructions to the choice of input stellar and atomic data is investigated. The quality of the fit to the average disk integrated line profile is found to be more important to DI analysis than the exact parameters used to generate the fit when the shape of the disk integrated line profile is dominated by rotational broadening. Fifteen absorption lines are used to generate fifteen individual reconstructions of each Pleiades target. Averaging reduces noise in the reconstructions. However, spurious features can persist at sub-observer longitudes. Such 'phase-ghosting' can largely be eliminated by including broad-band photometric observations in the analysis. Using the large number of reconstructions for a given star, uncertainties in the images are estimated. HII 686 shows one predominant feature at 77o latitude which is 700 K cooler than the surrounding photosphere. HII 3163 also shows one predominant feature centered at approximately 70o latitude. A spot temperature 1000 K cooler than the photosphere best reproduces the observations. P1724 shows a predominant feature (or features) centered at 30o latitude which is 800 K cooler than its photosphere. These results are discussed in light of recent theoretical observations and existing image reconstructions of similar objects. No correlations are found among reconstructions which could be attributed to line characteristics: equivalent width, excitation potential or depth of formation. This is also true for the LiI and KI

  4. Giant rotating magnetocaloric effect in the region of spin-reorientation transition in the NdCo₅ single crystal.

    Nikitin, S A; Skokov, K P; Koshkid'ko, Yu S; Pastushenkov, Yu G; Ivanova, T I


    We have investigated the anisotropy of the magnetocaloric effect in a NdCo₅ single crystal in a wide range of temperatures, including the spin-reorientation temperature region. In the field μ(0)H =1.3 T in the spin-reorientation region 250-310 K, we discovered a giant rotating magnetocaloric effect of ~ 1.6 K, caused by rotation of the magnetization vector. The calculations of the anisotropy magnetocaloric effect for the field μ(0)H =1.3 T have been carried out.

  5. A substellar companion to Pleiades HII 3441

    Konishi, Mihoko; Matsuo, Taro; Yamamoto, Kodai; Samland, Matthias; Sudo, Jun; Shibai, Hiroshi; Itoh, Yoichi; Fukagawa, Misato; Sumi, Takahiro; Kudo, Tomoyuki; Hashimoto, Jun; Kuzuhara, Masayuki; Kusakabe, Nobuhiko; Abe, Lyu; Akiyama, Eiji; Brandner, Wolfgang; Brandt, Timothy D.; Carson, Joseph C.; Feldt, Markus; Goto, Miwa; Grady, Carol A.; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S.; Henning, Thomas; Hodapp, Klaus W.; Ishii, Miki; Iye, Masanori; Janson, Markus; Kandori, Ryo; Knapp, Gillian R.; Kwon, Jungmi; McElwain, Michael W.; Mede, Kyle; Miyama, Shoken; Morino, Jun-Ichi; Moro-Martín, Amaya; Nishimura, Tetsuo; Oh, Daehyeon; Pyo, Tae-Soo; Serabyn, Eugene; Schlieder, Joshua E.; Suenaga, Takuya; Suto, Hiroshi; Suzuki, Ryuji; Takahashi, Yasuhiro H.; Takami, Michihiro; Takato, Naruhisa; Terada, Hiroshi; Thalmann, Christian; Turner, Edwin L.; Watanabe, Makoto; Wisniewski, John P.; Yamada, Toru; Takami, Hideki; Usuda, Tomonori; Tamura, Motohide


    We find a new substellar companion to the Pleiades member star, Pleiades HII 3441, using the Subaru telescope with adaptive optics. The discovery is made as part of the high-contrast imaging survey to search for planetary-mass and substellar companions in the Pleiades and young moving groups. The companion has a projected separation of 0{^''.}49 ± 0{^''.}02 (66 ± 2 au) and a mass of 68 ± 5 MJ based on three observations in the J-, H-, and Ks-bands. The spectral type is estimated to be M7 (˜2700 K), and thus no methane absorption is detected in the H band. Our Pleiades observations result in the detection of two substellar companions including one previously reported among 20 observed Pleiades stars, and indicate that the fraction of substellar companions in the Pleiades is about 10.0^{+26.1}_{-8.8}%. This is consistent with multiplicity studies of both the Pleiades stars and other open clusters.

  6. A Substellar Companion to Pleiades HII 3441

    Konishi, Mihoko; Yamamoto, Kodai; Samland, Matthias; Sudo, Jun; Shibai, Hiroshi; Itoh, Yoichi; Fukagawa, Misato; Sumi, Takahiro; Kudo, Tomoyuki; Hashimoto, Jun; Kuzuhara, Masayuki; Kusakabe, Nobuhiko; Abe, Lyu; Akiyama, Eiji; Brandner, Wolfgang; Brandt, Timothy D; Carson, Joseph C; Feldt, Markus; Goto, Miwa; Grady, Carol A; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S; Henning, Thomas; Hodapp, Klaus W; Ishii, Miki; Iye, Masanori; Janson, Markus; Kandori, Ryo; Knapp, Gillian R; Kwon, Jungmi; Mcelwain, Michael W; Mede, Kyle; Miyama, Shoken; Morino, Jun-Ichi; Moro-Mart'in, Amaya; Nishimura, Tetsuo; Oh, Daehyeon; Pyo, Tae-Soo; Serabyn, Eugene; Schlieder, Joshua E; Suenaga, Takuya; Suto, Hiroshi; Suzuki, Ryuji; Takahashi, Yasuhiro H; Takami, Michihiro; Takato, Naruhisa; Terada, Hiroshi; Thalmann, Christian; Turner, Edwin L; Watanabe, Makoto; Wisniewski, John P; Yamada, Toru; Takami, Hideki; Usuda, Tomonori; Tamura, Motohide


    We find a new substellar companion to the Pleiades member star, Pleiades HII 3441, using the Subaru telescope with adaptive optics. The discovery is made as part of the high-contrast imaging survey to search for planetary-mass and substellar companions in the Pleiades and young moving groups. The companion has a projected separation of 0".49 +/- 0".02 (66 +/- 2 AU) and a mass of 68 +/- 5 M_J based on three observations in the J-, H-, and K_S-band. The spectral type is estimated to be M7 (~2700 K), and thus no methane absorption is detected in the H band. Our Pleiades observations result in the detection of two substellar companions including one previously reported among 20 observed Pleiades stars, and indicate that the fraction of substellar companions in the Pleiades is about 10.0 +26.1/-8.8 %. This is consistent with multiplicity studies of both the Pleiades stars and other open clusters.

  7. A substellar companion to Pleiades HII 3441

    Konishi, Mihoko; Matsuo, Taro; Yamamoto, Kodai; Samland, Matthias; Sudo, Jun; Shibai, Hiroshi; Itoh, Yoichi; Fukagawa, Misato; Sumi, Takahiro; Kudo, Tomoyuki; Hashimoto, Jun; Kuzuhara, Masayuki; Kusakabe, Nobuhiko; Abe, Lyu; Akiyama, Eiji; Brandner, Wolfgang; Brandt, Timothy D.; Carson, Joseph C.; Feldt, Markus; Goto, Miwa; Grady, Carol A.; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S.; Henning, Thomas; Hodapp, Klaus W.; Ishii, Miki; Iye, Masanori; Janson, Markus; Kandori, Ryo; Knapp, Gillian R.; Kwon, Jungmi; McElwain, Michael W.; Mede, Kyle; Miyama, Shoken; Morino, Jun-Ichi; Moro-Martín, Amaya; Nishimura, Tetsuo; Oh, Daehyeon; Pyo, Tae-Soo; Serabyn, Eugene; Schlieder, Joshua E.; Suenaga, Takuya; Suto, Hiroshi; Suzuki, Ryuji; Takahashi, Yasuhiro H.; Takami, Michihiro; Takato, Naruhisa; Terada, Hiroshi; Thalmann, Christian; Turner, Edwin L.; Watanabe, Makoto; Wisniewski, John P.; Yamada, Toru; Takami, Hideki; Usuda, Tomonori; Tamura, Motohide


    We find a new substellar companion to the Pleiades member star, Pleiades HII 3441, using the Subaru telescope with adaptive optics. The discovery is made as part of the high-contrast imaging survey to search for planetary-mass and substellar companions in the Pleiades and young moving groups. The companion has a projected separation of 0{^''.}49 ± 0{^''.}02 (66 ± 2 au) and a mass of 68 ± 5 MJ based on three observations in the J-, H-, and Ks-bands. The spectral type is estimated to be M7 (˜2700 K), and thus no methane absorption is detected in the H band. Our Pleiades observations result in the detection of two substellar companions including one previously reported among 20 observed Pleiades stars, and indicate that the fraction of substellar companions in the Pleiades is about 10.0^{+26.1}_{-8.8}%. This is consistent with multiplicity studies of both the Pleiades stars and other open clusters.

  8. Giant Eruption of the Extremely Metal-Poor LBV in DDO 68

    Perepelitsyna, Y. A.; Pustilnik, S. A.


    Understanding the evolution of massive stars with metallicities much lower than that of the Sun (e.g., Zresearch until extremely large telescopes (ELTs) are in operation. Meantime, selection of good targets for future ELT research becomes actual. Here we present one of such important targets. The unusual void galaxy DDO68 has several star-forming (SF) regions with the gas metallicity Z = Z⊙/35 [12+log(O/H)=7.14]. In 2008, we discovered a luminous blue variable (LBV) star in its HII-region Knot 3. We present the LBV's V-band lightcurve for the time range of 1988 to 2016 using both our new and published data for Knot 3 brightness as well as the archive data from eleven telescopes. The prerequisite is an accurate estimate of the ‘minimal' (non-variable) V-band light for the Knot 3 underlying HII region. Its subtraction from the variable light of Knot 3 allows us to determine the full amplitude of the LBV variability at the level of δV ≳4m. This implies that the LBV has experienced a very rare event of a giant eruption during the years 2008-2011.

  9. Quantitative analysis of argyrophilic nuclear organizer regions in giant cell lesions of jaws.

    Sadri, Donia; Hejazi, Massoud; Jahanbani, Jahanfar; Forouzandeh, Aghdas


    Giant cell lesions of the jaws are considerably similar according to histopathologic characteristics yet show different clinical behaviors. These lesions include central giant cell granuloma (CGCG), aneurysmal bone cyst, Cherubism, and Brown tumor associated with hyperparathyroidism. The present study aimed to investigate AgNORs count in these lesions as a proliferative marker and to determine whether it can be used to discriminate between them or not. Forty-one cases of giant cell lesions of jaws were retrived from Oral Pathology Department (1987-2007). They included 21 cases of CGCG, eight cases of aneurysmal bone cyst (ABC), six cases of Cherubism, six cases of Brown tumor. The mean AgNORs count was calculated for all cases. To compare mean AgNORs in groups of lesions, ANOVA test was performed. Mean AgNOR counts were: (0/85 +/- 0/29) in CGCG, (0/76 +/- 0/32) in ABC (0/87 +/- 0/10) in Cherubism and (0/82 +/- 0/16) in Brown tumor. A significant difference was not observed in AgNOR counts among these groups of lesions. Jaws giant cell containing lesions have no acceptable differences in mean AgNORs.

  10. Large/giant meningiomas of posterior third ventricular region: falcotentorial or velum interpositum?

    Behari, Sanjay; Das, Kuntal Kanti; Kumar, Ashish; Mehrotra, Anant; Srivastava, Arun K; Sahu, Rabi N; Jaiswal, Awadhesh K


    Surgical excision of rare, large-to-giant posterior third ventricular (PTV) meningiomas [including velum-interpositum meningiomas (VIM; postero-superior venous complex displacement; without falco-tentorial attachment) and falco-tentorial meningiomas (FTM; falco-tentorial attachment; displacing major veins antero-inferiorly)] is extremely challenging. To study the management nuances in the excision of large-to-giant PTV meningiomas. Tertiary care referral center. Four patients with large (>3 cm; n = 2) and giant (>5 cm; n = 2) meningiomas (FTM = 2; VIM = 2, mean tumor size = 4.9 cm) underwent occipital transtentorial approach (OTT) for tumor excision. One also underwent a second-stage supracerebellar infratentorial (SCIT) approach. The side of approach was determined by lateral tumor extension and venous displacement (right = 3, left = 1). Near-total removal or subtotal excision (<10% remaining) with radiotherapy was performed in 2 patients each, respectively. At follow-up (mean: 14.75 months), clinical improvement without tumor recurrence/re-growth was achieved. Extent of excision was determined by position of great vein of Galen; tumor attachment to falco-tentorium or major veins; its consistency; its lateral and inferior extent; and, presence of a good tumor-neuraxial arachnoidal plane. OTT is the preferable approach for large-to-giant meningiomas as it provides a wider corridor and better delineation of tumor-neurovascular arachnoidal interface.

  11. Large/giant meningiomas of posterior third ventricular region: Falcotentorial or velum interpositum?

    Sanjay Behari


    Full Text Available Surgical excision of rare, large-to-giant posterior third ventricular (PTV meningiomas [including velum-interpositum meningiomas (VIM; postero-superior venous complex displacement; without falco-tentorial attachment and falco-tentorial meningiomas (FTM; falco-tentorial attachment; displacing major veins antero-inferiorly] is extremely challenging. To study the management nuances in the excision of large-to-giant PTV meningiomas. Tertiary care referral center. Four patients with large (>3 cm; n = 2 and giant (>5 cm; n = 2 meningiomas (FTM = 2; VIM = 2, mean tumor size = 4.9 cm underwent occipital transtentorial approach (OTT for tumor excision. One also underwent a second-stage supracerebellar infratentorial (SCIT approach. The side of approach was determined by lateral tumor extension and venous displacement (right = 3, left = 1. Near-total removal or subtotal excision (<10% remaining with radiotherapy was performed in 2 patients each, respectively. At follow-up (mean: 14.75 months, clinical improvement without tumor recurrence/re-growth was achieved. Extent of excision was determined by position of great vein of Galen; tumor attachment to falco-tentorium or major veins; its consistency; its lateral and inferior extent; and, presence of a good tumor-neuraxial arachnoidal plane. OTT is the preferable approach for large-to-giant meningiomas as it provides a wider corridor and better delineation of tumor-neurovascular arachnoidal interface.

  12. Hubble Space Telescope Hx Imaging of Star-forming Galaxies at z approximately equal to 1-1.5: Evolution in the Size and Luminosity of Giant H II Regions

    Livermore, R. C.; Jones, T.; Richard, J.; Bower, R. G.; Ellis, R. S.; Swinbank, A. M.; Rigby, J. R.; Smail, Ian; Arribas, S.; Rodriguez-Zaurin, J.; hide


    We present Hubble Space Telescope/Wide Field Camera 3 narrow-band imaging of the Ha emission in a sample of eight gravitationally lensed galaxies at z = 1-1.5. The magnification caused by the foreground clusters enables us to obtain a median source plane spatial resolution of 360 pc, as well as providing magnifications in flux ranging from approximately 10× to approximately 50×. This enables us to identify resolved star-forming HII regions at this epoch and therefore study their Ha luminosity distributions for comparisons with equivalent samples at z approximately 2 and in the local Universe. We find evolution in the both luminosity and surface brightness of HII regions with redshift. The distribution of clump properties can be quantified with an HII region luminosity function, which can be fit by a power law with an exponential break at some cut-off, and we find that the cut-off evolves with redshift. We therefore conclude that 'clumpy' galaxies are seen at high redshift because of the evolution of the cut-off mass; the galaxies themselves follow similar scaling relations to those at z = 0, but their HII regions are larger and brighter and thus appear as clumps which dominate the morphology of the galaxy. A simple theoretical argument based on gas collapsing on scales of the Jeans mass in a marginally unstable disc shows that the clumpy morphologies of high-z galaxies are driven by the competing effects of higher gas fractions causing perturbations on larger scales, partially compensated by higher epicyclic frequencies which stabilize the disc.

  13. The L-sigma Relation of Local HII Galaxies

    Bordalo, Vinicius


    We present for the first time a new data set of emission line widths for 118 star-forming regions in HII galaxies (HIIGs). This homogeneous set is used to investigate the L-sigma relation in conjunction with optical spectrophotometric observations. Peculiarities in the line profiles such as sharp lines, wings, asymmetries, and in some cases more than one component in emission were verified. From a new independent homogeneous set of spectrophotometric data we derived physical condition parameters and performed the statistical principal component analysis. We have investigated the potential role of metallicity (O/H), Hbeta equivalent width (WHbeta) and ionization ratio [OIII]/[OII] to account for the observational scatter of L-sigma relation. Our results indicate that the L-sigma relation for HIIGs is more sensitive to the evolution of the current starburst event (short-term evolution) and dated by WHbeta or even the [OIII]/[OII] ratio. The long-term evolution measured by O/H also plays a potential role in dete...

  14. Constraining the Dark Energy Equation of State with HII Galaxies

    Chávez, Ricardo; Basilakos, Spyros; Terlevich, Roberto; Terlevich, Elena; Melnick, Jorge; Bresolin, Fabio; González-Morán, Ana Luisa


    We use the HII galaxies $L - \\sigma$ relation and the resulting Hubble expansion cosmological probe of a sample of just 25 high-$z$ (up to $z \\sim 2.33$) HII galaxies, in a joint likelihood analysis with other well tested cosmological probes (CMB, BAOs) in an attempt to constrain the dark energy equation of state (EoS). The constraints, although still weak, are in excellent agreement with those of a similar joint analysis using the well established SNIa Hubble expansion probe. Interestingly, even with the current small number of available high redshift HII galaxies, the HII/BAO/CMB joint analysis gives a 13% improvement of the quintessence dark energy cosmological constraints compared to the BAO/CMB joint analysis. We have further performed extensive Monte Carlo simulations, with a realistic redshift sampling, to explore the extent to which the use of the $L - \\sigma$ relation, observed in HII galaxies, can constrain effectively the parameter space of the dark energy EoS. The simulations predict substantial i...

  15. Giant Condyloma Acuminatum in the Genital, Perineal and Perianal Region in a Pediatric Patient. Literature Review and Case Report

    Rodrigo Suárez-Ibarrola


    Full Text Available Condyloma acuminata is caused by the proliferation of squamous epithelial cells in the presence of human papilloma virus (HPV infection. There are several treatment options available for anogenital warts, however, none have proven to be more efficacious. We present the case of a 3 year-8 months-old male, diagnosed with human immunodeficiency virus (HIV infection, who presented with multiple warts in the anogenital region. Lesions were treated with imiquimod 5%, electrosurgical resection and interferon α-2b. Combination of electrofulguration and interferon α-2b is an effective treatment option for children with giant condyloma accuminatum although recurrence is expected within a short follow-up period.

  16. Measurement of the Am241(γ,n)Am240 reaction in the giant dipole resonance region

    Tonchev, A. P.; Hammond, S. L.; Howell, C. R.; Huibregtse, C.; Hutcheson, A.; Kelley, J. H.; Kwan, E.; Raut, R.; Rusev, G.; Tornow, W.; Kawano, T.; Vieira, D. J.; Wilhelmy, J. B.


    The photodisintegration cross section of the radioactive nucleus Am241 has been obtained using activation techniques and monoenergetic γ-ray beams from the HIγS facility. The induced activity of Am240 produced via the Am241(γ,n) reaction was measured in the energy interval from 9 to 16 MeV utilizing high-resolution γ-ray spectroscopy. The experimental data for the Am241(γ,n) reaction in the giant dipole resonance energy region are compared with statistical nuclear-model calculations.

  17. Giant Radio Halos in Galaxy Clusters as Probes of Particle Acceleration in Turbulent Regions

    G. Brunetti


    Giant radio halos in galaxy clusters probe mechanisms of particle acceleration connected with cluster merger events. Shocks and turbulence are driven in the inter-galactic medium (IGM) during clusters mergers and may have a deep impact on the non-thermal properties of galaxy clusters. Models of turbulent (re)acceleration of relativistic particles allow good correspondence with present observations, from radio halos to -ray upper limits, although several aspects of this complex scenario still remain poorly understood. After providing basic motivations for turbulent acceleration in galaxy clusters, we discuss relevant aspects of the physics of particle acceleration by MHD turbulence and the expected broad-band non-thermal emission from galaxy clusters. We discuss (in brief) the most important results of turbulent (re)acceleration models, the open problems, and the possibilities to test models with future observations. In this respect, further constraints on the origin of giant nearby radio halos can also be obtained by combining their (spectral and morphological) properties with the constraints from -ray observations of their parent clusters.

  18. Eventful Evolution of Giant Molecular Clouds in Dynamically Evolving Spiral Arms

    Baba, Junichi; Saitoh, Takayuki R


    The formation and evolution of giant molecular clouds (GMCs) in spiral galaxies have been investigated in the traditional framework of the combined quasi-stationary density wave and galactic shock model. However, our understanding of the dynamics of spiral arms is changing from the traditional spiral model to a dynamically evolving spiral model. In this study, we investigate the structure and evolution of GMCs in a dynamically evolving spiral arm using a three-dimensional N-body/hydrodynamic simulation of a barred spiral galaxy at parsec-scale resolution. This simulation incorporated self-gravity, molecular hydrogen formation, radiative cooling, heating due to interstellar far-ultraviolet radiation, and stellar feedback by both HII regions and Type-II supernovae. In contrast to a simple expectation based on the traditional spiral model, the GMCs exhibited no systematic evolutionary sequence across the spiral arm. Our simulation showed that the GMCs behaved as highly dynamic objects with eventful lives involvi...

  19. Peering into the Giant Planet Forming Region of the TW Hydrae Disk with the Gemini Planet Imager

    Rapson, Valerie A; Millar-Blanchaer, Maxwell A; Dong, Ruobing


    We present Gemini Planet Imager (GPI) adaptive optics near-infrared images of the giant planet-forming regions of the protoplanetary disk orbiting the nearby (D = 54 pc), pre-main sequence (classical T Tauri) star TW Hydrae. The GPI images, which were obtained in coronagraphic/polarimetric mode, exploit starlight scattered off small dust grains to elucidate the surface density structure of the TW Hya disk from 80 AU to within 10 AU of the star at 1.5 AU resolution. The GPI polarized intensity images unambiguously con?rm the presence of a gap in the radial surface brightness distribution of the inner disk. The gap is centered near 23 AU, with a width of 5 AU and a depth of 50%. In the context of recent simulations of giant planet formation in gaseous, dusty disks orbiting pre-main sequence stars, these results indicate that at least one young planet with a mass 0.2 M_J could be present in the TW Hya disk at an orbital semi-major axis similar to that of Uranus. If this (proto)planet is actively accreting gas fr...

  20. (. pi. sup +- ,. pi. sup +- prime N) reactions on sup 12 C and sup 208 Pb near the giant resonance region

    Yoo, Sung Hoon.


    Angular distributions for the {sup 12}C({pi}{sup {plus minus}}, {pi}{sup {plus minus}}{prime} p) and {sup 208}Pb({pi}{sup {plus minus}}, {pi}{sup {plus minus}}{prime} p or n) reactions near the giant resonance region have been measured at T{sub {pi}} = 180 MeV, and found different between {pi}{sup +} and {pi}{sup {minus}} data. This observation is interpreted as evidence for different excitation mechanisms dominating the {pi}{sup {minus}}-nucleus and {pi}{sup +}-nucleus interactions in the giant resonance region of these targets. A comparison with the single-nucleon knock-out distorted-wave impulse approximation calculations shows, even though these calculations underestimate ({pi}{sup {plus minus}}, {pi}{sup {plus minus}}{prime} N) data for both targets, the dominance of direct process for ({pi}{sup +}, {pi}{sup {plus}}{prime} p) or ({pi}{sup {minus}}, {pi}{sup {minus}}{prime} n) in contrast to ({pi}{sup {minus}}, {pi}{sup {minus}}{prime} p) or ({pi}{sup +}, {pi}{sup +}{prime} n). In the ({pi}{sup +}, {pi}{sup +}{prime} p) reaction proton-proton hole states are excited directly and appear to have a large probability for direct decay with escape width, whereas in ({pi}{sup {minus}}, {pi}{sup {minus}}{prime} p) the preferentially excited neutron-neutron hole doorway states couple to resonance states and decay with spreading width. This interpretation led us to suggest that the ratio of cross-sections for inelastic scattering to the giant resonance region should be written in terms of an incoherent sum of cross-sections to neutron and proton doorway states. In a heavy nucleus such as {sup 208}Pb, neutron and proton doorway states. In a heavy nucleus such as {sup 208}Pb, neutron and proton doorway states contribute incoherently because the different decay processes do not populate the same final states of the residual nucleus.

  1. The discoveries of WASP-91b, WASP-105b and WASP-107b: Two warm Jupiters and a planet in the transition region between ice giants and gas giants

    Anderson, D. R.; Collier Cameron, A.; Delrez, L.; Doyle, A. P.; Gillon, M.; Hellier, C.; Jehin, E.; Lendl, M.; Maxted, P. F. L.; Madhusudhan, N.; Pepe, F.; Pollacco, D.; Queloz, D.; Ségransan, D.; Smalley, B.; Smith, A. M. S.; Triaud, A. H. M. J.; Turner, O. D.; Udry, S.; West, R. G.


    We report the discoveries of three transiting exoplanets. WASP-91b is a warm Jupiter (1.34 MJup, 1.03 RJup) in a 2.8-day orbit around a metal-rich K3 star. WASP-105b is a warm Jupiter (1.8 MJup, 0.96 RJup) in a 7.9-day orbit around a metal-rich K2 star. WASP-107b is a warm super-Neptune/sub-Saturn (0.12 MJup, 0.94 RJup) in a 5.7-day orbit around a solar-metallicity K6 star. Considering that giant planets seem to be more common around stars of higher metallicity and stars of higher mass, it is notable that the hosts are all metal-rich, late-type stars. With orbital separations that place both WASP-105b and WASP-107b in the weak-tide regime, measurements of the alignment between the planets' orbital axes and their stars' spin axes may help us to understand the inward migration of short-period, giant planets. The mass of WASP-107b (2.2 MNep, 0.40 MSat) places it in the transition region between the ice giants and gas giants of the Solar System. Its radius of 0.94 RJup suggests that it is a low-mass gas giant with a H/He-dominated composition. The planet thus sets a lower limit of 2.2 MNep on the planetary mass above which large gaseous envelopes can be accreted and retained by proto-planets on their way to becoming gas giants. We may discover whether WASP-107b more closely resembles an ice giant or a gas giant by measuring its atmospheric metallicity via transmission spectroscopy, for which WASP-107b is a very good target. Based on observations made with: the WASP-South photometric survey instrument, the 0.6-m TRAPPIST robotic imager, and the EulerCam camera and the CORALIE spectrograph mounted on the 1.2-m Euler-Swiss telescope.The photometric time-series and radial-velocity data used in this work are only available at the CDS via anonymous ftp to ( or via

  2. Axial symmetry around the recoil axis for the 238U(α, α'f) reaction and the fission probability in the giant resonance region

    Leo, R. de; Harakeh, M.N.; Micheletti, S.; Plicht, J. van der; van der Woude, Adriaan; David, P.; Janszen, H.


    A measurement of the α-spectrum in the region of the isoscalar giant resonances from 238U at Eα = 120 MeV in coincidence with out-of-plane fission fragments shows the validity of the hypothesis of axial symmetry with respect to the recoil axis. Similar to what was observed in previous in-plane

  3. BOND: Bayesian Oxygen and Nitrogen abundance Determinations in giant H II regions using strong and semi-strong lines

    Asari, N Vale; Morisset, C; Fernandes, R Cid


    We present BOND, a Bayesian code to simultaneously derive oxygen and nitrogen abundances in giant H II regions. It compares observed emission lines to a grid of photoionization models without assuming any relation between O/H and N/O. Our grid spans a wide range in O/H, N/O and ionization parameter U, and covers different starburst ages and nebular geometries. Varying starburst ages accounts for variations in the ionizing radiation field hardness, which arise due to the ageing of H II regions or the stochastic sampling of the initial mass function. All previous approaches assume a strict relation between the ionizing field and metallicity. The other novelty is extracting information on the nebular physics from semi-strong emission lines. While strong lines ratios alone ([O III]/Hbeta, [O II]/Hbeta and [N II]/Hbeta) lead to multiple O/H solutions, the simultaneous use of [Ar III]/[Ne III] allows one to decide whether an H II region is of high or low metallicity. Adding He I/Hbeta pins down the hardness of the ...

  4. Evolution of Prolate Molecular Clouds at Hii Boundaries: II. Formation of BRCs of asymmetrical morphology

    Kinnear, T M; White, G J; Sugitani, K; Goodwin, S


    A systematic investigation on the evolution of a prolate cloud at an Hii boundary is conducted using Smoothed Particle Hydrodynamics (SPH) in order to understand the mechanism for a variety of irregular morphological structures found at the boundaries of various Hii regions. The prolate molecular clouds in this investigation are set with their semi-major axes at inclinations between 0 and 90 degrees to a plane parallel ionizing radiation flux. A set of 4 parameters, the number density n, the ratio of major to minor axis gamma, the inclination angle phi and the incident flux F_EUV, are used to define the initial state of the simulated clouds. The dependence of the evolution of a prolate cloud under Radiation Driven Implosion (RDI) on each of the four parameters is investigated. It is found that: i) in addition to the well studied standard type A, B or C Bright Rimmed Clouds (BRCs), many other types such as asymmetrical BRCs, filamentary structures and irregular horse-head structures could also be developed at ...

  5. Wind-Blown Bubbles and HII Regions around Massive Stars

    S. J. Arthur


    Full Text Available La evoluci on de las estrellas muy masivas est a dominada por su p erdida de masa, aunque las tasas de p erdida de masa no se conocen con mucha precisi on, particularmente una vez que la estrella sale de la secuencia principal. Los estudios de las nebulosas de anillo y de las cascarones de HI que rodean a muchas estrellas Wolf-Rayet (WR y variables azules luminosas (LBV proporcionan algo de informaci on acerca de la historia de la p erdida de masa en las etapas previas. Durante la secuencia principal y la fase WR los vientos estelares hipers onicos forman burbujas en el medio circunestelar e interestelar. Estas dos fases est an separadas por una etapa en donde la estrella pierde masa a una tasa muy alta pero a baja velocidad. Por lo tanto, el ambiente presupernova es determinado por la estrella progenitora misma, a un hasta distancias de algunas decenas de parsecs de la estrella. En este art culo, se describen las diferentes etapas en la evoluci on del medio circunestelar alrededar de una estrella de masa 40 M mediante simulaciones num ericas

  6. Massive Stars in the W33 Giant Molecular Complex

    Messineo, Maria; Figer, Donald F; Kudritzki, Rolf-Peter; Najarro, Francisco; Rich, R Michael; Menten, Karl M; Ivanov, Valentin D; Valenti, Elena; Trombley, Christine; Chen, C -H Rosie; Davies, Ben


    Rich in HII regions, giant molecular clouds are natural laboratories to study massive stars and sequential star formation. The Galactic star forming complex W33 is located at l=~12.8deg and at a distance of 2.4 kpc, has a size of ~10 pc and a total mass of (~0.8 - ~8.0) X 10^5 Msun. The integrated radio and IR luminosity of W33 - when combined with the direct detection of methanol masers, the protostellar object W33A, and protocluster embedded within the radio source W33 main - mark the region out as a site of vigorous ongoing star formation. In order to assess the long term star formation history, we performed an infrared spectroscopic search for massive stars, detecting for the first time fourteen early-type stars, including one WN6 star and four O4-7 stars. The distribution of spectral types suggests that this population formed during the last ~2-4 Myr, while the absence of red supergiants precludes extensive star formation at ages 6-30 Myr. This activity appears distributed throughout the region and does ...

  7. Thermally induced fluid reversed hexagonal (H(II)) mesophase.

    Amar-Yuli, Idit; Wachtel, Ellen; Shalev, Deborah E; Moshe, Hagai; Aserin, Abraham; Garti, Nissim


    In the present study we characterized the microstructures of the Lc and HII phases in a glycerol monooleate (GMO)/tricaprylin (TAG)/water mixture as a function of temperature. We studied the factors that govern the formation of a low-viscosity HII phase at relatively elevated temperatures (>35 degrees C). This phase has very valuable physical characteristics and properties. The techniques used were differential scanning calorimetry (DSC), wide- and small-angle X-ray scattering (WAXS and SAXS, respectively), NMR (self-diffusion and (2)H NMR), and Fourier transform infrared (FTIR) spectroscopies. The reverse hexagonal phase exhibited relatively rapid flow of water in the inner channels within the densely packed cylindrical aggregates of GMO with TAG molecules located in the interstices. The existence of two water diffusion peaks reflects the existence of both mobile water and hydration water at the GMO-water interface (hydrogen exchange between the GMO hydroxyls and water molecules). Above 35 degrees C, the sample became fluid yet hexagonal symmetry was maintained. The fluidity of the HII phase is explained by a significant reduction in the domain size and also perhaps cylinder length. This phenomenon was characterized by higher mobility of the GMO, lower mobility of the water, and a significant dehydration process.

  8. Epigenetic silencing of genes and microRNAs within the imprinted Dlk1-Dio3 region at human chromosome 14.32 in giant cell tumor of bone

    Lehner, Burkhard; Kunz, Pierre; Saehr, Heiner; Fellenberg, Joerg


    Background Growing evidence exists that the neoplastic stromal cell population (GCTSC) within giant cell tumors (GCT) originates from mesenchymal stem cells (MSC). In a previous study we identified a microRNA signature that differentiates between these cell types. Five differentially expressed microRNAs are located within the Dlk1-Dio3 region on chromosome 14. Aberrant regulation within this region is known to influence cell growth, differentiation and the development of cancer. The aim of th...

  9. A Series of Homologous Jets that Drove CMEs from The Giant Solar Acive Region of 2014 October

    Panesar, Navdeep K; Moore, Ronald L


    We report observations of homologous coronal jets and their coronal mass ejections (CMEs) observed by instruments onboard the Solar Dynamics Observatory (SDO) and Solar and Heliospheric Observatory (SOHO) spacecraft. The homologous jets originated from a location with emerging and canceling magnetic field at the southeast edge of the giant active region (AR) of 2014 October, NOAA 12192. This AR produced in its interior many non-jet major flare eruptions (X and M class) that made no CME. During 20-27 October, in contrast to the major-flare eruptions in the interior, six of the homologous jets from the edge resulted in CMEs. Each jet-driven CME( ~200-300 kms) was slower-moving than most CMEs; had angular width (20-50 degree) comparable to that of the base of a coronal streamer straddling the AR; and was of the `streamer-puff' variety, whereby the preexisting streamer was transiently inflated but not destroyed by the passage of the CME. Much of the transition-region-temperature plasma in the CME-producing jets e...

  10. X-ray Diagnostics of Giant Molecular Clouds in the Galactic Center Region and Past Activity of Sgr A*

    Odaka, Hirokazu; Watanabe, Shin; Tanaka, Yasuyuki; Khangulyan, Dmitry; Takahashi, Tadayuki; 10.1088/0004-637X/740/2/103


    Strong iron fluorescence at 6.4 keV and hard-X-ray emissions from giant molecular clouds in the Galactic center region have been interpreted as reflections of a past outburst of the Sgr A* supermassive black hole. Careful treatment of multiple interactions of photons in a complicated geometry is essential to modeling the reprocessed emissions from the dense clouds. We develop a new calculation framework of X-ray reflection from molecular clouds based on Monte Carlo simulations for accurate interpretation of high-quality observational data. By utilizing this simulation framework, we present the first calculations of morphologies and spectra of the reflected X-ray emission for several realistic models of Sgr B2, which is the most massive molecular cloud in our Galaxy. The morphology of scattered hard X-rays above 20 keV is significantly different from that of iron fluorescence due to their large penetrating power into dense regions of the cloud, probing the structure of the cloud. High-resolution spectra provid...

  11. Acomprehensive study of high metallicity giant extragalactic h ii regions: chemical abundances

    Marcelo Castellanos; Díaz, Angeles I.; Elena Terlevich


    Hemos realizado observaciones espectrofotom etricas en el optico e infrarrojo cercano de 15 regiones H II en las galaxias espirales NGC 628, NGC 925, NGC 1232 y NGC 1637. Dichas observaciones han sido realizadas con una amplia cobertura espectral y con una resoluci on su ciente para detectar y medir tanto las d ebiles l neas aurorales como las caracter sticas de estrellas Wolf-Rayet (WR). Hemos derivado la temperatura electr onica en las regiones observadas con el n de investi...

  12. Acomprehensive study of high metallicity giant extragalactic h ii regions: chemical abundances

    Marcelo Castellanos


    Full Text Available Hemos realizado observaciones espectrofotom etricas en el optico e infrarrojo cercano de 15 regiones H II en las galaxias espirales NGC 628, NGC 925, NGC 1232 y NGC 1637. Dichas observaciones han sido realizadas con una amplia cobertura espectral y con una resoluci on su ciente para detectar y medir tanto las d ebiles l neas aurorales como las caracter sticas de estrellas Wolf-Rayet (WR. Hemos derivado la temperatura electr onica en las regiones observadas con el n de investigar la estructura de ionizaci on de las mismas y la composici on qu mica del gas. De esta manera, hemos seleccionado de la muestra de Van Zee et al. (1998, aquellas regiones H II gigantes cuya metalicidad, obtenida a partir de calibraciones emp ricas basadas en las l neas prohibidas del ox geno, es solar o sobresolar.

  13. Embedded Star Clusters in the W51 Giant Molecular Cloud

    Kumar, M S N; Davis, C J


    We present sub-arcsecond (0.35"-0.9"), near-infrared J,H,K band photometric observations of six fields along the W51 Giant Molecular Cloud (W51 GMC). Our observations reveal four new, embedded clusters and provide a new high-resolution (0.35") view of the W51IRS2 (G49.5-0.4) region. The cluster associated with G48.9-0.3 is found to be a double cluster enclosed in a nest of near-infrared nebulosity. We construct stellar surface density maps for four major clusters in the W51 GMC. These unveil the underlying hierarchical structure. Color-color and color-magnitude diagrams for each of these clusters show clear differences in the embedded stellar populations and indicate the relative ages of these clusters. In particular, the clusters associated with the HII regions G48.9-0.3 and G49.0-0.3 are found to have a high fraction of YSOs and are therefore considered the youngest of all the near-infrared clusters in the W51 GMC. The estimated masses of the individual clusters, when summed, yield a total stellar mass of ~...

  14. Peripheral giant cell granuloma

    Padam Narayan Tandon


    Full Text Available Peripheral giant cell granuloma or the so-called "giant cell epulis" is the most common oral giant cell lesion. It normally presents as a soft tissue purplish-red nodule consisting of multinucleated giant cells in a background of mononuclear stromal cells and extravasated red blood cells. This lesion probably does not represent a true neoplasm, but rather may be reactive in nature, believed to be stimulated by local irritation or trauma, but the cause is not certainly known. This article reports a case of peripheral giant cell granuloma arising at the maxillary anterior region in a 22-year-old female patient. The lesion was completely excised to the periosteum level and there is no residual or recurrent swelling or bony defect apparent in the area of biopsy after a follow-up period of 6 months.

  15. Isomeric ratios in photonuclear reactions of molybdenum isotopes induced by bremsstrahlung in the giant dipole resonance region

    Thiep, Tran Duc; An, Truong Thi; Cuong, Phan Viet; Vinh, Nguyen The; Hue, Bui Minh; Belov, A. G.; Maslov, O. D.; Mishinsky, G. V.; Zhemenik, V. I.


    We have determined the isomeric ratios of isomeric pairs 97m,gNb, 95m,gNb and 91m,gMo produced in 98Mo(γ, p)97m,gNb, 96Mo(γ, p)95m,gNb and 92Mo(γ, n)91m,gMo photonuclear reactions in the giant dipole resonance (GDR) region by the activation method. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy, neutron configuration, channel effect and direct and pre-equilibrium processes in (γ, p) photonuclear reactions. In this work the isomeric ratios for 97m,gNb from 14 to 19 MeV, for 195m,gNb from14 to 24 MeV except 20 and 23.5 MeV and for 91m,gMo at 14 and 15 MeV are the first time measurements.

  16. Giant landslides and turbidity currents in the Agadir Canyon Region, NW-Africa

    Krastel, Sebastian; Wynn, Russell B.; Stevenson, Christopher; Feldens, Peter; Mehringer, Lisa; Schürer, Anke


    Coring and drilling of the Moroccan Turbidite System off NW-Africa revealed a long sequence of turbidites, mostly sourced from the Moroccan continental margin and the volcanic Canary Islands. The largest individual flow deposits in the Moroccan Turbidite System contain sediment volumes >100 km3, although these large-scale events are relatively infrequent with a recurrence interval of 10,000 years (over the last 200,000 years). The largest siliciclastic flow in the last 200,000 years was the 'Bed 5 event', which transported 160 km3 of sediment up to 2000 km from the Agadir Canyon region to the southwest Madeira Abyssal Plain. While the Moroccan Turbidite System is extremely well investigated, almost no data from the source region, i.e. the Agadir Canyon, are available. Understanding why some submarine landslides remain as coherent blocks of sediment throughout their passage downslope, while others mix and disintegrate almost immediately after initial failure, is a major scientific challenge, which was addressed in the Agadir Canyon source region during RV Maria S. Merian Cruise MSM32 in late 2013. A major landslide area was identified 200 km south of the Agadir Canyon. A landslide was traced from this failure area to the Agadir Canyon. This landslide entered the canyon in about 2500 m water depth. Despite a significant increase in slope angle, the landslide did not disintegrate into a turbidity current when entering the canyon but moved on as landslide for at least another 200 km down the canyon. The age of the landslide ( 145 ka) does not correspond to any major turbidte deposit in the Moroccan Turbidite System, further supporting the fact that the landslide did not disintegrate into a major turbidity current. A core taken about 350 m above the thalweg in the head region of Agadir Canyon shows a single coarse-grained turbidite, which resembles the composition of the Bed 5 event in the Madeira Abyssal Plain. Hence, the Bed 5 turbidite originated as a failure in the

  17. Dense Clumps in Giant Molecular Clouds in the Large Magellanic Cloud: Density and Temperature Derived from $^{13}$CO($J=3-2$) Observations

    Minamidani, Tetsuhiro; Mizuno, Yoji; Mizuno, Norikazu; Kawamura, Akiko; Onishi, Toshikazu; Hasegawa, Tetsuo; Tatematsu, Ken'ichi; Takekoshi, Tatsuya; Sorai, Kazuo; Moribe, Nayuta; Torii, Kazufumi; Sakai, Takeshi; Muraoka, Kazuyuki; Tanaka, Kunihiko; Ezawa, Hajime; Kohno, Kotaro; Kim, Sungeun; Rubio, Mónica; Fukui, Yasuo


    In order to precisely determine temperature and density of molecular gas in the Large Magellanic Cloud, we made observations of optically thin $^{13}$CO($J=3-2$) transition by using the ASTE 10m telescope toward 9 peaks where $^{12}$CO($J=3-2$) clumps were previously detected with the same telescope. The molecular clumps include those in giant molecular cloud (GMC) Types I (with no signs of massive star formation), II (with HII regions only), and III (with HII regions and young star clusters). We detected $^{13}$CO($J=3-2$) emission toward all the peaks and found that their intensities are 3 -- 12 times lower than those of $^{12}$CO($J=3-2$). We determined the intensity ratios of $^{12}$CO($J=3-2$) to $^{13}$CO($J=3-2$), $R^{12/13}_{3-2}$, and $^{13}$CO($J=3-2$) to $^{13}$CO($J=1-0$), $R^{13}_{3-2/1-0}$, at 45$\\arcsec$ resolution. These ratios were used for radiative transfer calculations in order to estimate temperature and density of the clumps. The parameters of these clumps range kinetic temperature $T\\ma...

  18. High-Resolution Measurement of the {sup 4}He({gamma},n) Reaction in the Giant Resonance Region

    Nilsson, Bjoern


    A comprehensive near-threshold {sup 4}He(gamma,n) absolute cross section measurement has been performed at the high-resolution tagged-photon facility MAX-lab located in Lund, Sweden. The 20 < Eg < 45 MeV tagged photons (covering the Giant Dipole Resonance energy region) were directed towards a liquid {sup 4}He target, and knocked-out neutrons were detected in a pair of 60 cm x 60 cm vetoed NE213A liquid scintillator arrays. The intense and varying charge-neutral experimental backgrounds were carefully quantified and removed from the data using a precision fitting procedure. Eight average laboratory angles (30, 45, 60, 75, 90, 105, 120, and 135 deg) were investigated for eight photon energy bins (25, 27, 29, 31, 35, 36, 39, and 41 MeV), resulting in 64 differential cross sections. These angular distributions were integrated to produce total cross sections as a function of photon energy. The resulting cross sections peak at 1.9 mb at a photon energy of 27 MeV, and fall off to a near-constant value of 1.1 mb by 36 MeV. Further, they are in excellent agreement with those measured by Sims et al. using tagged photons in the Quasi-Deuteron energy region. Overall, the results favor modern theoretical models which are based upon a charge-symmetric nucleon-nucleon force, in marked contrast to the recommendations made by Calarco et al. in 1983 based on the sparse {sup 4}He(gamma,n) data available at the time.

  19. On the onset of secondary stellar generations in giant star-forming regions and massive star clusters

    Palouš, J.; Wünsch, R. [Astronomical Institute, Academy of Sciences of the Czech Republic, Boční II 1401, 14131 Prague (Czech Republic); Tenorio-Tagle, G. [Instituto Nacional de Astrofísica Optica y Electrónica, AP 51, 72000 Puebla (Mexico)


    Here we consider the strong evolution experienced by the matter reinserted by massive stars, both in giant star-forming regions driven by a constant star formation rate and in massive and coeval superstar clusters. In both cases we take into consideration the changes induced by stellar evolution on the number of massive stars, the number of ionizing photons, and the integrated mechanical luminosity of the star-forming regions. The latter is at all times compared with the critical luminosity that defines, for a given size, the lower mechanical luminosity limit above which the matter reinserted via strong winds and supernova explosions suffers frequent and recurrent thermal instabilities that reduce its temperature and pressure and inhibit its exit as part of a global wind. Instead, the unstable reinserted matter is compressed by the pervasive hot gas, and photoionization maintains its temperature at T ∼ 10{sup 4} K. As the evolution proceeds, more unstable matter accumulates and the unstable clumps grow in size. Here we evaluate the possible self-shielding of thermally unstable clumps against the UV radiation field. Self-shielding allows for a further compression of the reinserted matter, which rapidly develops a high-density neutral core able to absorb in its outer skin the incoming UV radiation. Under such conditions the cold (T ∼ 10 K) neutral cores soon surpass the Jeans limit and become gravitationally unstable, creating a new stellar generation with the matter reinserted by former massive stars. We present the results of several calculations of this positive star formation feedback scenario promoted by strong radiative cooling and mass loading.

  20. A review of the biology and conservation of the Cope's giant salamander Dicamptodon copei Nussbaum, 1970 (Amphibia: Caudata: Dicamptodontidae) in the Pacific northwestern region of the USA

    Alex D. Foster; Deanna H. Olson; Lawrence L.C. Jones


    The Cope’s Giant Salamander Dicamptodon copei is a stream dwelling amphibian reliant on cool streams, native to forested areas primarily west of the crest of the Cascade Range in the Pacific Northwest region, USA. Unlike other members of the genus, adult D. copei are most often found in a paedomorphic form, and rarely transforms to a terrestrial stage. As a result,...

  1. Dynamos of giant planets

    Busse, F H; 10.1017/S1743921307000920


    Possibilities and difficulties of applying the theory of magnetic field generation by convection flows in rotating spherical fluid shells to the Giant Planets are outlined. Recent progress in the understanding of the distribution of electrical conductivity in the Giant Planets suggests that the dynamo process occurs predominantly in regions of semiconductivity. In contrast to the geodynamo the magnetic field generation in the Giant Planets is thus characterized by strong radial conductivity variations. The importance of the constraint on the Ohmic dissipation provided by the planetary luminosity is emphasized. Planetary dynamos are likely to be of an oscillatory type, although these oscillations may not be evident from the exterior of the planets.

  2. The Stellar Mass Distribution in the Giant Star Forming Region NGC 346

    Sabbi, E; Nota, A; Tosi, M; Gallagher, J; Smith, L J; Angeretti, L; Meixner, M; Oey, M S; Walterbos, R; Pasquali, A


    Deep F555W and F814W Hubble Space Telescope ACS images are the basis for a study of the present day mass function (PDMF) of NGC346, the largest active star forming region in the Small Magellanic Cloud (SMC). We find a PDMF slope of Gamma=-1.43+/-0.18 in the mass range 0.8-60 Mo, in excellent agreement with the Salpeter Initial Mass Function (IMF) in the solar neighborhood. Caveats on the conversion of the PDMF to the IMF are discussed. The PDMF slope changes, as a function of the radial distance from the center of the NGC 346 star cluster, indicating a segregation of the most massive stars. This segregation is likely primordial considering the young age (~3 Myr) of NGC346, and its clumpy structure which suggests that the cluster has likely not had sufficient time to relax. Comparing our results for NGC346 with those derived for other star clusters in the SMC and the Milky Way (MW), we conclude that, while the star formation process might depend on the local cloud conditions, the IMF does not seem to be affect...

  3. An unusual giant spiral arc in the polar cap region during the northward phase of a Coronal Mass Ejection

    L. Rosenqvist


    Full Text Available The shock arrival of an Interplanetary Coronal Mass Ejection (ICME at ~09:50 UT on 22 November 1997 resulted in the development of an intense (Dst<−100 nT geomagnetic storm at Earth. In the early, quiet phase of the storm, in the sheath region of the ICME, an unusual large spiral structure (diameter of ~1000 km was observed at very high latitudes by the Polar UVI instrument. The evolution of this structure started as a polewardly displaced auroral bulge which further developed into the spiral structure spreading across a large part of the polar cap. This study attempts to examine the cause of the chain of events that resulted in the giant auroral spiral. During this period the interplanetary magnetic field (IMF was dominantly northward (Bz>25 nT with a strong duskward component (By>15 nT resulting in a highly twisted tail plasma sheet. Geotail was located at the equatorial dawnside magnetotail flank and observed accelerated plasma flows exceeding the solar wind bulk velocity by almost 60%. These flows are observed on the magnetosheath side of the magnetopause and the acceleration mechanism is proposed to be typical for strongly northward IMF. Identified candidates to the cause of the spiral structure include a By induced twisted magnetotail configuration, the development of magnetopause surface waves due to the enhanced pressure related to the accelerated magnetosheath flows aswell as the formation of additional magnetopause deformations due to external solar wind pressure changes. The uniqeness of the event indicate that most probably a combination of the above effects resulted in a very extreme tail topology. However, the data coverage is insufficient to fully investigate the physical mechanism behind the observations.

  4. Observações em Radiofreqüências do complexo de Regiões HII Compactas RCW 95

    Barres de Almeida, Ulisses


    In this work we studied the complex of compact HII (CHII) regions RCW 95. The cloud is about 10'x10' and was mapped on the radio continuum emission at 43 GHz; a survey of water lines was also conducted at 22.2 GHz, corresponding to the 616 - 523 rotational transition of this molecule. The observations were made with the 14-meter single-dish antennae of the Itaptinga radio observatory, in Atibaia, ruled by INPE (Nacional Institute for Space Research, Brazil). For the continuum observations we made several scans in right ascension throughout the whole of the source spaced by 1' in declination, that were following combined to produce a map of isotemperatures for the cloud. The study resulted on the identification of resolved radio continuum sources associated with all the three IRAS sources in the region: IRAS 15408-5356, 15411-5352 and 15412-5359, all with far-IR colours characteristics of CHII regions. The water line survey resulted on the positive identification of maser emission associated with the three IRAS sources, supporting the evidences for these regions to harbour massive young stars. Two other unresolved HII regions, unassociated with far-IR sources, were also discovered through detailed analyses of the profiles of the radio continuum scans. The regions associated to the IRAS sources 15408-5356 and 15411-5352 were already known to be regions of massive star formation, whilst the stellar population associated to IRAS 15412-5359 had not been studied before. The discovery of water lines and the presence of a thermal continuum source on this direction suggested that this region could also contain young stars. We then conducted a study of the stellar population inside a region of 2'2' around this IRAS source using near-IR (J, H and K) band images from 2MASS catalogue. Throught this we were able to identify a significant population of massive stars, including one O9V star and some early BV that were charged responsibility for the ionization of the gas in the

  5. Last refuge of the scoundrel: Effects of a giant impact on the south polar region of Enceladus

    Roberts, J. H.; Stickle, A. M.; Craft, K.


    The south polar region on Enceladus is characterized by plume activity and a substantial thermal anomaly. Although tides are the likeliest energy source, this heat tends to be lost faster than it is produced, resulting in the geologically rapid freezing of any global subsurface ocean and severe reduction of subsequent tidal heating. Moreover, tidal heating is symmetric about the equator, and no corresponding thermal anomaly or activity is observed in the north. The presence of significant lateral variations in the mechanical properties of the ice shell can break this symmetry. Here we examine the effects of a large impact on both the initial meltwater production and on softening of the surrounding ice by the shock heating using hydrocode modeling, and model the subsequent tidal dissipation and thermal evolution of the ice shell in response to the impact heating. We simulated the vertical impact of a 5 km diameter icy projectile at 20 km/s into a 40 km thick ice shell over an ocean, scaled to create a 150 km wide crater, the approximate size of the south polar terrain (SPT). The impact heat diffuses away in 1 My, a result that is similar to that of earlier studies of a very slow collision with a co-orbital object. However, the impact heating softens the ice and enhances the tidal heating locally. Nevertheless, this thermal anomaly fades in a few My. Unless such an impact occurred in the very recent past, the thermal effects would not be observable today. Another consideration, however, is that a projectile capable of creating the SPT would cause extensive fracturing in the ice to a depth of tens of km below the melt zone, and would completely melt through any shell thinner than 30 km, enabling transfer of material between the surface and an ocean. Such an impact would also produce a significant amount of melt, 2×105 km3, which may drain into the subsurface ocean, and reduce the topography in the vicinity of the impact by 3 km. Ongoing work to model the tectonics

  6. Chandra observations of the HII complex G5.89-0.39 and TeV gamma-ray source HESSJ1800-240B

    Hampton, E J; Hofmann, W; Horns, D; Uchiyama, Y; Wagner, S


    We present the results of our investigation, using a Chandra X-ray observation, into the stellar population of the massive star formation region G5.89-0.39, and its potential connection to the coincident TeV gamma-ray source HESSJ1800-240B. G5.89-0.39 comprises two separate HII regions G5.89-0.39A and G5.89-0.39B (an ultra-compact HII region). We identified 159 individual X-ray point sources in our observation using the source detection algorithm \\texttt{wavdetect}. 35 X-ray sources are associated with the HII complex G5.89-0.39. The 35 X-ray sources represent an average unabsorbed luminosity (0.3-10\\,keV) of $\\sim10^{30.5}$\\,erg/s, typical of B7-B5 type stars. The potential ionising source of G5.89-0.39B known as Feldt's star is possibly identified in our observation with an unabsorbed X-ray luminosity suggestive of a B7-B5 star. The stacked energy spectra of these sources is well-fitted with a single thermal plasma APEC model with kT$\\sim$5\\,keV, and column density N$_{\\rm H}=2.6\\times10^{22}$\\,cm$^{-2}$ (A...

  7. H(II) centers in natural silica under repeated UV laser irradiations

    Messina, F.; Cannas, M.; Boscaino, R.


    We investigated the kinetics of H(II) centers (=Ge'-H) in natural silica under repeated 266nm UV irradiations performed by a Nd:YAG pulsed laser. UV photons temporarily destroy these paramagnetic defects, their reduction being complete within 250 pulses. After re-irradiation, H(II) centers grow again, and the observed recovery kinetics depends on the irradiation dose; multiple 2000 pulses re-irradiations induce the same post-irradiation kinetics of H(II) centers after each exposure cycle. The...

  8. An Old Supernova Remnant within an HII Complex at l {\\approx} 173{\\circ}: FVW 172.8+1.5

    Kang, Ji-hyun; Salter, Chris


    We present the results of HI 21-cm line observations to explore the nature of the high-velocity (HV) HI gas at l ~ 173{\\circ} . In low-resolution Hi surveys this HV gas appears as faint, wing-like, HI emission that extends to velocities beyond those allowed by Galactic rotation. We designate this feature FVW (Forbidden Velocity Wing) 172.8+1.5. Our high-resolution (3.'4) Arecibo HI observations show that FVW 172.8+1.5 is composed of knots, filaments, and ring-like structures distributed over an area a few degrees in extent. These HV HI emission features are confined within the limits of the HII complex G173+1.5, which is composed of five Sharpless HII regions distributed along a radio continuum loop of size 4{\\circ}.4 {\\times} 3{\\circ}.4, or ~ 138 pc {\\times} 107 pc, at a distance of 1.8 kpc. G173+1.5 is one of the largest star-forming regions in the outer Galaxy. We demonstrate that the HV HI gas is well correlated with the radio continuum loop and that the two seem to trace an expanding shell. The expansion...

  9. Giant Planets

    Guillot, Tristan


    We review the interior structure and evolution of Jupiter, Saturn, Uranus and Neptune, and giant exoplanets with particular emphasis on constraining their global composition. Compared to the first edition of this review, we provide a new discussion of the atmospheric compositions of the solar system giant planets, we discuss the discovery of oscillations of Jupiter and Saturn, the significant improvements in our understanding of the behavior of material at high pressures and the consequences for interior and evolution models. We place the giant planets in our Solar System in context with the trends seen for exoplanets.

  10. HII mesophase as a drug delivery system for topical application of methyl salicylate.

    Liang, Xin; Chen, Yu-Lin; Jiang, Xiao-Jing; Wang, Sheng-Mei; Zhang, Ji-Wen; Gui, Shuang-Ying


    The main objective of this study was to develop reversed hexagonal (HII) mesophase for transdermal delivery of methyl salicylate. The formulation was prepared, characterized and evaluated for its skin penetration in vitro and skin retention in vivo. Preliminary pharmacodynamics and skin irritation were also investigated. The formulation was identified as hexagonal structure. In vitro study exhibited that HII mesophase enhanced the skin permeation by delivering 2.61 times more methyl salicylate than the commercially available cream. Meanwhile, HII mesophase presented higher bioavailability as AUC(0-24) and AUC(0-∞) were 32.894μg·mL(-1) and 32.935μg·mL(-1) respectively, while the cream were 12.791μg·mL(-1) and 12.970μg·mL(-1). Preliminary pharmacodynamics studies demonstrated that HII mesophase possessed anti-inflammatory and analgesic effects for inhibiting paw edema, granuloma and pain. MeSa HII mesophase showed no skin irritation on the normal rat skin. Thus, HII mesophase was considered as an effective delivery system for MeSa.

  11. X-ray emission from the giant molecular clouds in the Galactic Center region and the discovery of new X-ray sources

    Sidoli, L; Treves, A; Parmar, A N; Turolla, R; Favata, F


    We report the results of X-ray (2-10 keV) observations of the giant molecular clouds SgrB, SgrC and SgrD in the Galactic Center region, together with the discovery of the point-like source SAXJ1748.2-2808. The data have been obtained with the MECS instrument on the BeppoSAX satellite. The core of SgrB2 has an X-ray luminosity of 6x10^34 erg/s and its spectrum is characterized by a strong Fe emission line at 6.5 keV with an equivalent width of 2 keV. Faint diffuse X-ray emission is detected from SgrC and from the SNR G1.05-0.15 (SgrD). A new, unresolved source with a strong Fe line has been discovered in the SgrD region. This source, SAXJ1748.2-2808, is probably associated with a SiO and OH maser source at the Galactic Center distance. If so, its luminosity is 10^34 erg/s. We propose that the X-ray emission from SAX J1748.2-2808 is produced either by protostars or by a giant molecular cloud core. Emission from sources similar to SAX J1748.2-2808 could have an impact on the expected contribution on the observed...

  12. Star Cluster Complexes and the Host Galaxy in Three HII Galaxies: Mrk 36, UM 408, and UM 461

    Lagos, Patricio; Nigoche-Netro, A; Carrasco, Eleazar Rodrigo


    We present a stellar population study of three HII galaxies (Mrk 36, UM 408, and UM 461) based on the analysis of new ground-based high resolution near-infrared J, H and Kp broad-band and Br narrow-band images obtained with Gemini/NIRI. We identify and determine relative ages and masses of the elementary star clusters and/or star cluster complexes of the starburst regions in each of these galaxies by comparing the colors with evolutionary synthesis models that include the contribution of stellar continuum, nebular continuum and emission lines. We found that the current star cluster formation efficiency in our sample of low luminosity HII galaxies is ~10%. Therefore, most of the recent star formation is not in massive clusters. Our findings seem to indicate that the star formation mode in our sample of galaxies is clumpy, and that these complexes are formed by a few massive star clusters with masses > 10^4 Mo. The age distribution of these star cluster complexes shows that the current burst started recently an...

  13. Attosecond time delay in the photoionization of Mn in the $3p \\rightarrow 3d$ giant resonance region

    Dolmatov, V K; Deshmukh, P C; Manson, S T


    The dramatic effect of the $3p \\rightarrow 3d$ giant autoionization resonance on time delay of photoemission from the $3d$ and $4s$ valence subshells of the Mn atom is unraveled. Strong sensitivity of the time delay of the $4s$ photoemission to the final-state term of the ion-remainder [${\\rm Mn^{+}}(4s^{1},$$^{5}S)$ vs. ${\\rm Mn^{+}}(4s^{1},$$^{7}S)$] is discovered. The features of time delay uncovered in Mn photoionization are expected to be general properties of transition-metal atoms and ions. The "spin-polarized" random phase approximation with exchange was employed in the study.

  14. The Dense Filamentary Giant Molecular Cloud G23.0-0.4: Birthplace of Ongoing Massive Star Formation

    Su, Yang; Shao, Xiangjun; Yang, Ji


    We present observations of 1.5 square degree maps of the 12CO, 13CO, and C18O (J=1-0) emission toward the complex region of the supernova remnant (SNR) W41 and SNR G22.7-0.2. A massive (~5E5Msun), large (~84x15 pc), and dense (~10E3 cm^-3) giant molecular cloud (GMC), G23.0-0.4 with VLSR~77 km/s, is found to be adjacent to the two SNRs. The GMC displays a filamentary structure approximately along the Galactic plane. The filamentary structure of the dense molecular gas, traced by C18O (J=1-0) emission, is also coincident well with the distribution of the dust-continuum emission in the direction. Two dense massive MC clumps, two 6.7 GHz methanol masers, and one HII/SNR complex, associated with the 77 km/s GMC G23.0-0.4, are aligned along the filamentary structure, indicating the star forming activity within the GMC. These sources have periodic projected spacing of 0.18-0.26degree along the giant filament, which is consistent well with the theoretical predictions of 0.22degree. It indicates that the turbulence s...

  15. Star Formation in HII Galaxies. Properties of the ionized gas

    Hägele, G F; Terlevich, E; Pérez-Montero, E; Terlevich, R; Cardaci, M V


    We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the production and calibration of empirical relations between the different line temperatures that should superseed currently used ones based on very simple, and poorly tested, photo-ionization model sequences. Then, these observations are analysed applying a methodology designed to obtain accurate elemental abundances of oxygen, sulphur, nitrogen, neon, argon and iron in the ionsied gas. Four electron temperatures and one electron density are derived from the observed forbidden line ratios using the five-level atom approximation. For our best objects errors of 1% in T([OIII]), 3% in T([OII]) and 5% in T([SIII]) are achieved with a resulting accuracy between 5 and 9% in total oxygen abundances, O/H. These accuracies are expected to improve as better calibrations based on more precise me...

  16. An Improved Neural Network for Regional Giant Panda Habitat Suitability Mapping: A Case Study in Ya’an Prefecture

    Jingwei Song


    Full Text Available Expert knowledge is a combination of prior information and subjective opinions based on long-experience; as such it is often not sufficiently objective to produce convincing results in animal habitat suitability index mapping. In this study, an animal habitat assessment method based on a learning neural network is proposed to reduce the level of subjectivity in animal habitat assessments. Based on two hypotheses, this method substitutes habitat suitability index with apparent density and has advantages over conventional ones such as those based on analytical hierarchy process or multivariate regression approaches. Besides, this method is integrated with a learning neural network and is suitable for building non-linear transferring functions to fit complex relationships between multiple factors influencing habitat suitability. Once the neural network is properly trained, new earth observation data can be integrated for rapid habitat suitability monitoring which could save time and resources needed for traditional data collecting approaches through extensive field surveys. Giant panda (Ailuropoda melanoleuca natural habitat in Ya’an prefecture and corresponding landsat images, DEM and ground observations are tested for validity of using the methodology reported. Results show that the method scores well in key efficiency and performance indicators and could be extended for habitat assessments, particularly of other large, rare and widely distributed animal species.

  17. On The Effect of Giant Planets on the Scattering of Parent Bodies of Iron Meteorite from the Terrestrial Planet Region into the Asteroid Belt: A Concept Study

    Haghighipour, Nader


    In their model for the origin of the parent bodies of iron meteorites, Bottke et al proposed differentiated planetesimals that were formed in the region of 1-2 AU during the first 1.5 Myr, as the parent bodies, and suggested that these objects and their fragments were scattered into the asteroid belt as a result of interactions with planetary embryos. Although viable, this model does not include the effect of a giant planet that might have existed or been growing in the outer regions. We present the results of a concept study where we have examined the effect of a planetary body in the orbit of Jupiter on the early scattering of planetesimals from terrestrial region into the asteroid belt. We integrated the orbits of a large battery of planetesimals in a disk of planetary embryos, and studied their evolutions for different values of the mass of the planet. Results indicate that when the mass of the planet is smaller than 10 Earth-masses, its effects on the interactions among planetesimals and planetary embryo...

  18. High quality, giant crystalline-Ge stripes on insulating substrate by rapid-thermal-annealing of Sn-doped amorphous-Ge in solid-liquid coexisting region

    Ryo Matsumura


    Full Text Available Formation of large-grain (≥30 μm Ge crystals on insulating substrates is strongly desired to achieve high-speed thin-film transistors. For this purpose, we propose the methods of Sn-doping into amorphous-Ge combined with rapid-thermal-annealing (RTA in the solid-liquid coexisting temperature region for the Ge-Sn alloy system. The densities of micro-crystal-nuclei formed in this temperature region become low by tuning the RTA temperature close to the liquidus curve, which enhances the lateral growth of GeSn. Thanks to the very small segregation coefficient of Sn, almost all Sn atoms segregate toward edges of the stripes during growth. Agglomeration of GeSn degrades the surface morphologies; however, it is significantly improved by lowering the initial Sn concentration. As a result, pure Ge with large crystal grains (∼40 μm with smooth surface are obtained by optimizing the initial Sn concentration as low as 3 ∼ 5%. Lateral growth lengths are further increased through decreasing the number of nuclei in stripes by narrowing stripe width. In this way, high-crystallinity giant Ge crystals (∼200 μm are obtained for the stripe width of 3 μm. This “Si-seed free” technique for formation of large-grain pure Ge crystals is very useful to realize high-performance thin-film devices on insulator.

  19. High quality, giant crystalline-Ge stripes on insulating substrate by rapid-thermal-annealing of Sn-doped amorphous-Ge in solid-liquid coexisting region

    Matsumura, Ryo; Kai, Yuki; Chikita, Hironori; Sadoh, Taizoh; Miyao, Masanobu


    Formation of large-grain (≥30 μm) Ge crystals on insulating substrates is strongly desired to achieve high-speed thin-film transistors. For this purpose, we propose the methods of Sn-doping into amorphous-Ge combined with rapid-thermal-annealing (RTA) in the solid-liquid coexisting temperature region for the Ge-Sn alloy system. The densities of micro-crystal-nuclei formed in this temperature region become low by tuning the RTA temperature close to the liquidus curve, which enhances the lateral growth of GeSn. Thanks to the very small segregation coefficient of Sn, almost all Sn atoms segregate toward edges of the stripes during growth. Agglomeration of GeSn degrades the surface morphologies; however, it is significantly improved by lowering the initial Sn concentration. As a result, pure Ge with large crystal grains (˜40 μm) with smooth surface are obtained by optimizing the initial Sn concentration as low as 3 ˜ 5%. Lateral growth lengths are further increased through decreasing the number of nuclei in stripes by narrowing stripe width. In this way, high-crystallinity giant Ge crystals (˜200 μm) are obtained for the stripe width of 3 μm. This "Si-seed free" technique for formation of large-grain pure Ge crystals is very useful to realize high-performance thin-film devices on insulator.

  20. Physical characteristics of G331.5-0.1: The luminous central region of a Giant Molecular Cloud

    Merello, Manuel; Garay, Guido; Nyman, Lars-Ake; Evans, Neal J; Walmsley, C Malcolm


    We report molecular line and dust continuum observations toward the high-mass star forming region G331.5-0.1, one of the most luminous regions of massive star-formation in the Milky Way, located at the tangent region of the Norma spiral arm, at a distance of 7.5 kpc. Molecular emission was mapped toward the G331.5-0.1 GMC in the CO (J=1-0) and C18O (J=1-0) lines with NANTEN, while its central region was mapped in CS (J=2-1 and J=5-4) with SEST, and in CS (J=7-6) and 13CO (J=3-2) with ASTE. Continuum emission mapped at 1.2 mm with SIMBA and at 0.87 mm with LABOCA reveal the presence of six compact and luminous dust clumps, making this source one of the most densely populated central regions of a GMC in the Galaxy. The dust clumps are associated with molecular gas and they have the following average properties: size of 1.6 pc, mass of 3.2x10^3 Msun, molecular hydrogen density of 3.7x10^4 cm^{-3}, dust temperature of 32 K, and integrated luminosity of 5.7x10^5 Lsun, consistent with values found toward other mass...

  1. 3D sph simulations of giant herbig-haro flows and jet-cloud interactions in star formation regions

    Elisabete M. de Gouveia Dal Pino


    Full Text Available Describimos algunos resultados recientes de simulaciones tridimensionales con hidrodin amica de part culas suavizadas (SPH de chorros densos con enfriamiento radiativo en regiones de formaci on estelar. Discutimos la estructura y cinem atica de los objetos HH gigantes recientemente detectados y la interacci on de chorros HH con las nubes densas y compactas que los rodean.

  2. Giant Temperature Coefficient of Resistivity and Cryogenic Sensitivity in Silicon with Galvanically Displaced Gold Nanoparticles in Freeze-Out Region.

    Lee, Seung-Hoon; Hwang, Seongpil; Jang, Jae-Won


    The temperature coefficient of resistivity (TCR) and cryogenic sensitivity (Sv) of p-type silicon (p-Si) in the low-temperature region (10-30 K) are remarkably improved by increasing the coverage of galvanically displaced Au nanoparticles (NPs). By increase of the galvanic displacement time from 10 to 30 s, the average surface roughness (Ra) of the samples increases from 0.31 to 2.31 nm and the coverage rate of Au NPs increases from 3.1% to 21.9%. In the freeze-out region of the sample, an up to 103% increase of TCR and dramatically improved Sv of p-Si (∼5813%) are observed with Au coverage of 21.9% compared to p-Si without galvanically displaced Au NPs. By means of a finite element method (FEM) simulation study, it was found that the increase of surface roughness and a number of Au NPs on p-Si results in a higher temperature gradient and thermoelectric power to cause the unusual TCR and Sv values in the samples.

  3. A Large-Scale Genetic Analysis Reveals a Strong Contribution of the HLA Class II Region to Giant Cell Arteritis Susceptibility

    Carmona, F. David; Mackie, Sarah L.; Martín, Jose-Ezequiel; Taylor, John C.; Vaglio, Augusto; Eyre, Stephen; Bossini-Castillo, Lara; Castañeda, Santos; Cid, Maria C.; Hernández-Rodríguez, José; Prieto-González, Sergio; Solans, Roser; Ramentol-Sintas, Marc; González-Escribano, M. Francisca; Ortiz-Fernández, Lourdes; Morado, Inmaculada C.; Narváez, Javier; Miranda-Filloy, José A.; Martínez-Berriochoa, Agustín; Unzurrunzaga, Ainhoa; Hidalgo-Conde, Ana; Madroñero-Vuelta, Ana B.; Fernández-Nebro, Antonio; Ordóñez-Cañizares, M. Carmen; Escalante, Begoña; Marí-Alfonso, Begoña; Sopeña, Bernardo; Magro, César; Raya, Enrique; Grau, Elena; Román, José A.; de Miguel, Eugenio; López-Longo, F. Javier; Martínez, Lina; Gómez-Vaquero, Carmen; Fernández-Gutiérrez, Benjamín; Rodríguez-Rodríguez, Luis; Díaz-López, J. Bernardino; Caminal-Montero, Luis; Martínez-Zapico, Aleida; Monfort, Jordi; Tío, Laura; Sánchez-Martín, Julio; Alegre-Sancho, Juan J.; Sáez-Comet, Luis; Pérez-Conesa, Mercedes; Corbera-Bellalta, Marc; García-Villanueva, M. Jesús; Fernández-Contreras, M. Encarnación; Sanchez-Pernaute, Olga; Blanco, Ricardo; Ortego-Centeno, Norberto; Ríos-Fernández, Raquel; Callejas, José L.; Fanlo-Mateo, Patricia; Martínez-Taboada, Víctor M.; Beretta, Lorenzo; Lunardi, Claudio; Cimmino, Marco A.; Gianfreda, Davide; Santilli, Daniele; Ramirez, Giuseppe A.; Soriano, Alessandra; Muratore, Francesco; Pazzola, Giulia; Addimanda, Olga; Wijmenga, Cisca; Witte, Torsten; Schirmer, Jan H.; Moosig, Frank; Schönau, Verena; Franke, Andre; Palm, Øyvind; Molberg, Øyvind; Diamantopoulos, Andreas P.; Carette, Simon; Cuthbertson, David; Forbess, Lindsy J.; Hoffman, Gary S.; Khalidi, Nader A.; Koening, Curry L.; Langford, Carol A.; McAlear, Carol A.; Moreland, Larry; Monach, Paul A.; Pagnoux, Christian; Seo, Philip; Spiera, Robert; Sreih, Antoine G.; Warrington, Kenneth J.; Ytterberg, Steven R.; Gregersen, Peter K.; Pease, Colin T.; Gough, Andrew; Green, Michael; Hordon, Lesley; Jarrett, Stephen; Watts, Richard; Levy, Sarah; Patel, Yusuf; Kamath, Sanjeet; Dasgupta, Bhaskar; Worthington, Jane; Koeleman, Bobby P.C.; de Bakker, Paul I.W.; Barrett, Jennifer H.; Salvarani, Carlo; Merkel, Peter A.; González-Gay, Miguel A.; Morgan, Ann W.; Martín, Javier


    We conducted a large-scale genetic analysis on giant cell arteritis (GCA), a polygenic immune-mediated vasculitis. A case-control cohort, comprising 1,651 case subjects with GCA and 15,306 unrelated control subjects from six different countries of European ancestry, was genotyped by the Immunochip array. We also imputed HLA data with a previously validated imputation method to perform a more comprehensive analysis of this genomic region. The strongest association signals were observed in the HLA region, with rs477515 representing the highest peak (p = 4.05 × 10−40, OR = 1.73). A multivariate model including class II amino acids of HLA-DRβ1 and HLA-DQα1 and one class I amino acid of HLA-B explained most of the HLA association with GCA, consistent with previously reported associations of classical HLA alleles like HLA-DRB1∗04. An omnibus test on polymorphic amino acid positions highlighted DRβ1 13 (p = 4.08 × 10−43) and HLA-DQα1 47 (p = 4.02 × 10−46), 56, and 76 (both p = 1.84 × 10−45) as relevant positions for disease susceptibility. Outside the HLA region, the most significant loci included PTPN22 (rs2476601, p = 1.73 × 10−6, OR = 1.38), LRRC32 (rs10160518, p = 4.39 × 10−6, OR = 1.20), and REL (rs115674477, p = 1.10 × 10−5, OR = 1.63). Our study provides evidence of a strong contribution of HLA class I and II molecules to susceptibility to GCA. In the non-HLA region, we confirmed a key role for the functional PTPN22 rs2476601 variant and proposed other putative risk loci for GCA involved in Th1, Th17, and Treg cell function. PMID:25817017

  4. The Identification of Extreme Asymptotic Giant Branch Stars and Red Supergiants in M33 by 24 {\\mu}m Variability

    Montiel, Edward J; Clayton, Geoffrey C; Engelbracht, Charles W; Johnson, Christopher B


    We present the first detection of 24 {\\mu}m variability in 24 sources in the Local Group galaxy M33. These results are based on 4 epochs of MIPS observations, which are irregularly spaced over ~750 days. We find that these sources are constrained exclusively to the Holmberg radius of the galaxy, which increases their chances of being members of M33. We have constructed spectral energy distributions (SEDs) ranging from the optical to the sub-mm to investigate the nature of these objects. We find that 23 of our objects are most likely heavily self-obscured, evolved stars; while the remaining source is the Giant HII region, NGC 604. We believe that the observed variability is the intrinsic variability of the central star reprocessed through their circumstellar dust shells. Radiative transfer modeling was carried out to determine their likely chemical composition, luminosity, and dust production rate (DPR). As a sample, our modeling has determined an average luminosity of (3.8 $\\pm$ 0.9) x 10$^4$ L$_\\odot$ and a ...

  5. The metallicity of circumnuclear star forming regions

    Díaz, A I; Castellanos, M; Hägele, G F


    We present a spectrophotometric study of circumnuclear star forming regions (CNSFR) in the early type spiral galaxies: NGC 2903, NGC 3351 and NGC 3504, all of them of over solar metallicity according to standard empirical calibrations. A detailed determination of their abundances is made after careful subtraction of the very prominent underlying stellar absorption. It is found that most regions show the highest abundances in HII region-like objects. The relative N/O and S/O abundances are discussed. In is also shown that CNSFR, as a class, segregate from the disk HII region family, clustering around smaller ``softness parameter" -- \\eta' -- values, and therefore higher ionizing temperatures.

  6. Studying the interstellar medium of HII/BCD galaxies using IFU spectroscopy

    Lagos, Patricio


    We review the results from our studies, and previous published work, on the spatially resolved physical properties of a sample of HII/BCD galaxies, as obtained mainly from integral-field unit spectroscopy with Gemini/GMOS and VLT/VIMOS. We confirm that, within observational uncertainties, our sample galaxies show nearly spatially constant chemical abundances, similar to other low-mass starburst galaxies. They also show He II 4686 emission with properties being suggestive of a mix of excitation sources, with Wolf-Rayet stars being excluded as the primary one. Finally, in this contribution we include a list of all HII/BCD galaxies studied thus far with integral-field unit spectroscopy.

  7. Investigating the origin of cyclical wind variability in hot massive stars - II. Hydrodynamical simulations of corotating interaction regions using realistic spot parameters for the O giant ξ Persei

    David-Uraz, A.; Owocki, S. P.; Wade, G. A.; Sundqvist, J. O.; Kee, N. D.


    OB stars exhibit various types of spectral variability historically associated with wind structures, including the apparently ubiquitous discrete absorption components (DACs). These features have been proposed to be caused either by magnetic fields or non-radial pulsations. In this second paper of this series, we revisit the canonical phenomenological hydrodynamical modelling used to explain the formation of DACs by taking into account modern observations and more realistic theoretical predictions. Using constraints on putative bright spots located on the surface of the O giant ξ Persei derived from high precision space-based broad-band optical photometry obtained with the Microvariability and Oscillations of Stars (MOST) space telescope, we generate 2D hydrodynamical simulations of corotating interaction regions in its wind. We then compute synthetic ultraviolet (UV) resonance line profiles using Sobolev Exact Integration and compare them with historical timeseries obtained by the International Ultraviolet Explorer (IUE) to evaluate if the observed behaviour of ξ Persei's DACs is reproduced. Testing three different models of spot size and strength, we find that the classical pattern of variability can be successfully reproduced for two of them: the model with the smallest spots yields absorption features that are incompatible with observations. Furthermore, we test the effect of the radial dependence of ionization levels on line driving, but cannot conclusively assess the importance of this factor. In conclusion, this study self-consistently links optical photometry and UV spectroscopy, paving the way to a better understanding of cyclical wind variability in massive stars in the context of the bright spot paradigm.

  8. The interplay between ionized gas and massive stars in the HII galaxy IIZw70: integral field spectroscopy with PMAS

    Kehrig, C; Sánchez, S F; Telles, E; Pérez-Montero, E; Martin-Gordon, D


    We performed an integral field spectroscopic study for the HII galaxy IIZw70 in order to investigate the interplay between its ionized interstellar medium (ISM) and the massive star formation (SF). Observations were taken in the optical spectral range (3700-6800 A) with the Potsdam Multi-Aperture Spectrophotometer (PMAS) attached to the 3.5 m telescope at CAHA. We created and analysed maps of spatially distributed emission-lines, continuum emission and properties of the ionized ISM (e.g. physical-chemical conditions, dust extinction, kinematics). We investigated the relation of these properties to the spatial distribution and evolutionary stage of the massive stars. For the first time we detected the presence of Wolf-Rayet (WR) stars in this galaxy. The peak of the ionized gas emission coincides with the location of the WR bump. The region of the galaxy with lower dust extinction corresponds to the region that shows the lowest values of velocity dispersion and radial velocity. The overall picture suggests tha...

  9. Separating gas-giant and ice-giant planets by halting pebble accretion

    Lambrechts, M.; Johansen, A.; Morbidelli, A.


    In the solar system giant planets come in two flavours: gas giants (Jupiter and Saturn) with massive gas envelopes, and ice giants (Uranus and Neptune) with much thinner envelopes around their cores. It is poorly understood how these two classes of planets formed. High solid accretion rates, necessary to form the cores of giant planets within the life-time of protoplanetary discs, heat the envelope and prevent rapid gas contraction onto the core, unless accretion is halted. We find that, in fact, accretion of pebbles (~cm sized particles) is self-limiting: when a core becomes massive enough it carves a gap in the pebble disc. This halt in pebble accretion subsequently triggers the rapid collapse of the super-critical gas envelope. Unlike gas giants, ice giants do not reach this threshold mass and can only bind low-mass envelopes that are highly enriched by water vapour from sublimated icy pebbles. This offers an explanation for the compositional difference between gas giants and ice giants in the solar system. Furthermore, unlike planetesimal-driven accretion scenarios, our model allows core formation and envelope attraction within disc life-times, provided that solids in protoplanetary discs are predominantly made up of pebbles. Our results imply that the outer regions of planetary systems, where the mass required to halt pebble accretion is large, are dominated by ice giants and that gas-giant exoplanets in wide orbits are enriched by more than 50 Earth masses of solids.

  10. A Large-Scale Genetic Analysis Reveals a Strong Contribution of the HLA Class II Region to Giant Cell Arteritis Susceptibility

    David Carmona, F.; Mackie, Sarah L.; Martin, Jose-Ezequiel; Taylor, John C.; Vaglio, Augusto; Eyre, Stephen; Bossini-Castillo, Lara; Castaneda, Santos; Cid, Maria C.; Hernandez-Rodriguez, Jose; Prieto-Gonzalez, Sergio; Solans, Roser; Ramentol-Sintas, Marc; Francisca Gonzalez-Escribano, M.; Ortiz-Fernandez, Lourdes; Morado, Inmaculada C.; Narvaez, Javier; Miranda-Filloy, Jose A.; Beretta, Lorenzo; Lunardi, Claudio; Cimmino, Marco A.; Gianfreda, Davide; Santilli, Daniele; Ramirez, Giuseppe A.; Soriano, Alessandra; Muratore, Francesco; Pazzola, Giulia; Addimanda, Olga; Wijmenga, Cisca; Witte, Torsten; Schirmer, Jan H.; Moosig, Frank; Schoenau, Verena; Franke, Andre; Palm, Oyvind; Molberg, Oyvind; Diamantopoulos, Andreas P.; Carette, Simon; Cuthbertson, David; Forbess, Lindsy J.; Hoffman, Gary S.; Khalidi, Nader A.; Koening, Curry L.; Langford, Carol A.; McAlear, Carol A.; Moreland, Larry; Monach, Paul A.; Pagnoux, Christian; Seo, Philip; Spiera, Robert; Sreih, Antoine G.; Warrington, Kenneth J.; Ytterberg, Steven R.; Gregersen, Peter K.; Pease, Colin T.; Gough, Andrew; Green, Michael; Hordon, Lesley; Jarrett, Stephen; Watts, Richard; Levy, Sarah; Patel, Yusuf; Kamath, Sanjeet; Dasgupta, Bhaskar; Worthington, Jane; Koeleman, Bobby P. C.; de Bakker, Paul I. W.; Barrett, Jennifer H.; Salvarani, Carlo; Merkel, Peter A.; Gonzalez-Gay, Miguel A.; Morgan, Ann W.; Martin, Javier


    We conducted a large-scale genetic analysis on giant cell arteritis (GCA), a polygenic immune-mediated vasculitis. A case-control cohort, comprising 1,651 case subjects with GCA and 15,306 unrelated control subjects from six different countries of European ancestry, was genotyped by the Immunochip a

  11. Transforming giants.

    Kanter, Rosabeth Moss


    Large corporations have long been seen as lumbering, inflexible, bureaucratic--and clueless about global developments. But recently some multinationals seem to be transforming themselves: They're engaging employees, moving quickly, and introducing innovations that show true connection with the world. Harvard Business School's Kanter ventured with a research team inside a dozen global giants--including IBM, Procter & Gamble, Omron, CEMEX, Cisco, and Banco Real--to discover what has been driving the change. After conducting more than 350 interviews on five continents, she and her colleagues came away with a strong sense that we are witnessing the dawn of a new model of corporate power: The coordination of actions and decisions on the front lines now appears to stem from widely shared values and a sturdy platform of common processes and technology, not from top-down decrees. In particular, the values that engage the passions of far-flung workforces stress openness, inclusion, and making the world a better place. Through this shift in what might be called their guidance systems, the companies have become as creative and nimble as much smaller ones, even while taking on social and environmental challenges of a scale that only large enterprises could attempt. IBM, for instance, has created a nonprofit partnership, World Community Grid, through which any organization or individual can donate unused computing power to research projects and see what is being done with the donation in real time. IBM has gained an inspiring showcase for its new technology, helped business partners connect with the company in a positive way, and offered individuals all over the globe the chance to contribute to something big.

  12. Experimental Exploration on Rainfall-induced Mass Re-mobilization after Giant Earthquake: A case study in Wenchuan earthquake hit region, China

    Yang, Zongji; Bogaard, Thom. A.; Qiao, Jianping; Jiang, Yuanjun


    Prevention and mitigation of rainfall induced geological hazards after the Ms=8 Wenchuan earthquake on May 12th, 2008 were gained more significance for the rebuild of earthquake hit regions in China. After the Wenchuan earthquake, there were thousands of slopes failure, which were much more susceptible to subsequent heavy rainfall and many even transformed into potential debris flows. An typical example can be found in the catastrophic disaster occurred in Zhongxing County, Chengdu City on 10th July, 2013 in which the unknown fractured slope up the mountain was triggered by a downpour and transformed into subsequent debris flow which wiped the community downstream, about 200 victims were reported in that tragic event. The transform patterns of rainfall-induced mass re-mobilization was categorized into three major type as the erosion of fractured slopes, initiate on loosen deposit and outbreak of landslide (debris flow) dams according to vast field investigation in the earthquake hit region. Despite the widespread and hidden characters,the complexity of the process also demonstrated in the transforms of the mass re-mobilized by the erosion of both gravity and streams in the small watersheds which have never been reported before the giant Wenchuan Earthquake in many regions. As a result, an increasing number of questions for disaster relief and mitigation were proposed including the threshold of early warning and measurement of the volume for the design of mitigation measures on rainfall-induced mass re-mobilization in debris flow gullies. This study is aimed for answer the essential questions about the threshold and amount of mass initiation triggered by the subsequent rainfall in post earthquake time. In this study, experimental tests were carried out for simulating the failure of the rainfall-induced mass re-mobilization in respectively in a natural co-seismic fractured slope outside and the debris flow simulation platform inside the laboratory. A natural

  13. Giant Cell Arteritis

    Giant cell arteritis is a disorder that causes inflammation of your arteries, usually in the scalp, neck, and arms. ... arteries, which keeps blood from flowing well. Giant cell arteritis often occurs with another disorder called polymyalgia ...

  14. Giant Intradiverticular Bladder Tumor

    Noh, Mohamad Syafeeq Faeez Md; Aziz, Ahmad Fuad Abdul; Ghani, Khairul Asri Mohd; Siang, Christopher Lee Kheng; Yunus, Rosna; Yusof, Mubarak Mohd


    Patient: Male, 74 Final Diagnosis: Giant intradiverticular bladder tumor with metastasis Symptoms: Hematuria Medication:— Clinical Procedure: — Specialty: Urology Objective: Rare disease Background: Intradiverticular bladder tumors are rare. This renders diagnosis of an intradiverticular bladder tumor difficult. Imaging plays a vital role in achieving the diagnosis, and subsequently staging of the disease. Case Report: A 74-year-old male presented to our center with a few months history of constitutional symptoms. Upon further history, he reported hematuria two months prior to presentation, which stopped temporarily, only to recur a few days prior to coming to the hospital. The patient admitted to having lower urinary tract symptoms. However, there was no dysuria, no sandy urine, and no fever. Palpation of his abdomen revealed a vague mass at the suprapubic region, which was non tender. In view of his history and the clinical examination findings, an ultrasound of the abdomen and computed tomography (CT) was arranged. These investigations revealed a giant tumor that seemed to be arising from a bladder diverticulum, with a mass effect and hydronephrosis. He later underwent operative intervention. Conclusions: Intradiverticular bladder tumors may present a challenge to the treating physician in an atypical presentation; thus requiring a high index of suspicion and knowledge of tumor pathophysiology. As illustrated in our case, CT with its wide availability and multiplanar imaging capabilities offers a useful means for diagnosis, disease staging, operative planning, and follow-up. PMID:28246375

  15. Studies show giant panda could survive


    @@ The giant panda (Ailuropoda melanoleuca) is not a relic species, and it can survive, according to scientists. Employing microsatellite and mitochondrial control region (CR) sequences as genetic markers, CAS researchers have obtained some key information about the giant panda and its recent evolution history. Their discovery that the lovely creature still possesses high genetic diversity and evolution potentials challenges the hypothesis suggesting the giant panda is facing an"evolutionary dead-end." The research was reported in a recent issue of Molecular Biology and Evolution by a team of scientists led by Prof.WEI Fuwen of the CAS Institute of Zoology and Prof. Michael W.Bruford of Cardiff University.

  16. Growth and Destruction of Disks: Combined HI and HII View

    Bershady, Matthew; Crawford, Steven


    How large disk galaxies have evolved in, and out of, the blue cloud of actively star-forming galaxies as a function of environment and time is an outstanding question. Some of the largest disks become systems like M31, M33 and the Milky Way today. In denser environments, it appears they transform onto the red sequence. Tracking disk systems since z<0.5 as a function HI mass, dynamical mass, and environment should be possible in the coming decade. HI and optical data combined can sample outer and inner disk dynamics to connect halo properties with regions of most intense star-formation, and the gas reservoir to the consumption rate. We describe existing and future IFUs on 4-10m telescopes that complement upcoming HI surveys for studying disks at z<0.5. Multiple units, deployable over large fields-of-view, and with logarithmic sampling will yield kinematic and star-formation maps and properties of the stellar populations, resolving the core but retaining sensitivity to disk outskirts.

  17. Giant sialocele following facial trauma

    Medeiros Júnior,Rui; Rocha Neto,Alípio Miguel da; Queiroz, Isaac Vieira; Cauby,Antônio de Figueiredo; Gueiros,Luiz Alcino Monteiro; Leão,Jair Carneiro


    Injuries in the parotid and masseter region can cause serious impairment secondary to damage of important anatomical structures. Sialocele is observed as facial swelling associated with parotid duct rupture due to trauma. The aim of this paper is to report a case of a giant traumatic sialocele in the parotid gland, secondary to a knife lesion in a 40-year-old woman. Conservative measures could not promote clinical resolution and a surgical intervention for the placement of a vacuum drain was ...

  18. Molecular Lines of 13 Glactic Infrared Bubble Regions

    Yan, Q Z; Zhang, B; Lu, D R; Chen, X; Tang, Z H


    We investigated the physical properties of molecular clouds and star formation processes around infrared bubbles which are essentially expanding HII regions. We performed observations of 13 galactic infrared bubble fields containing 18 bubbles. Five molecular lines, 12CO (J=1-0), 13CO (J=1-0), C18O(J=1-0), HCN (J=1-0), and HCO+ (J=1-0), were observed, and several publicly available surveys, GLIMPSE, MIPSGAL, ATLASGAL, BGPS, VGPS, MAGPIS, and NVSS, were used for comparison. We find that these bubbles are generally connected with molecular clouds, most of which are giant. Several bubble regions display velocity gradients and broad shifted profiles, which could be due to the expansion of bubbles. The masses of molecular clouds within bubbles range from 100 to 19,000 solar mass, and their dynamic ages are about 0.3-3.7 Myr, which takes into account the internal turbulence pressure of surrounding molecular clouds. Clumps are found in the vicinity of all 18 bubbles, and molecular clouds near four of these bubbles w...

  19. VizieR Online Data Catalog: Spectrophotometric distances of HII regions (Moises+, 2011)

    Moises, A. P.; Damineli, A.; Figueredo, E.; Blum, R. D.; Conti, P. S.; Barbosa, C. L.


    The J-band (λ1.28um, δλ=0.3um), H-band (λ1.63um, δλ=0.3um) and Ks-band (λ2.19um, δλ=0.4um) images were obtained on the nights of 1999 May 1, 4 and 20, 2000 May 19 and 21 and 2001 July 10 and 12, at the Cerro Tololo Inter-American Observatory (CTIO) 4-m Blanco telescope, using the facility's infrared imager OSIRIS, which has a field of view (FOV) of 93x93arcsec2 and a pixel scale of 0.161arcsec/pixel. On the nights of 2005 Jult 3-6 and 11 and 2006 June 3-7, we obtained images using the facility's infrared imager ISPI (with a FOV of 10.25x10.25arcmin2 and a pixel scale of 0.3arcsec/pix), also at the 4-m Blanco telescope. Also, on the nights of 1998 August 28 and 29, we obtained images on the CTIO 4-m telescope using the facility's infrared imager CIRIM (with a FOV of 102x102arcsec2 and a pixel scale of 0.40arcsec/pix). (3 data files).

  20. Photoevaporation Flows in Blister HII Regions: I. Smooth Ionization Fronts and Application to the Orion Nebula

    Henney, W J; Garcia-Diaz, M T; Garcia-Diaz, Ma. T.


    We present hydrodynamical simulations of the photoevaporation of a cloud with large-scale density gradients, giving rise to an ionized, photoevaporation flow. The flow is found to be approximately steady during the large part of its evolution, during which it can resemble a "champagne flow" or a "globule flow" depending on the curvature of the ionization front. The distance from source to ionization front and the front curvature uniquely determine the structure of the flow, with the curvature depending on the steepness of the lateral density gradient in the neutral cloud. We compare these simulations with both new and existing observations of the Orion nebula and find that a model with a mildly convex ionization front can reproduce the profiles of emission measure, electron density, and mean line velocity for a variety of emitting ions on scales of 10^{17} to 10^{18} cm. The principal failure of our model is that we cannot explain the large observed widths of the [O I] 6300 Angstrom line that forms at the ion...

  1. Properties of compact 250 \\mu m emission and HII regions in M33 (HERM33ES)

    Verley, S; Kramer, C; Xilouris, E M; Boquien, M; Calzetti, D; Combes, F; Buchbender, C; Braine, J; Quintana-Lacaci, G; Tabatabaei, F S; Lord, S; Israel, F; Stacey, G; van der Werf, P


    Within the framework of the HERM33ES Key Project, using the high resolution and sensitivity of the Herschel photometric data, we study the compact emission in the Local Group spiral galaxy M33 to investigate the nature of the compact SPIRE emission sources. We extracted a catalogue of sources at 250um in order to investigate the nature of this compact emission. Taking advantage of the unprecedented Herschel resolution at these wavelengths, we also focus on a more precise study of some striking Halpha shells in the northern part of the galaxy. We present a catalogue of 159 compact emission sources in M33 identified by SExtractor in the 250um SPIRE band that is the one that provides the best spatial resolution. We also measured fluxes at 24um and Halpha for those 159 extracted sources. The morphological study of the shells also benefits from a multiwavelength approach including Halpha, far-UV from GALEX, and infrared from both Spitzer IRAC 8um and MIPS 24um in order to make comparisons. For the 159 compact sour...

  2. Giant Cell Arteritis

    ... Cryopyrin-Associated Autoinflammatory Syndrome (CAPS) (Juvenile) Dermatomyositis (Juvenile) Familial Mediterranean Fever (Juvenile) Fibromyalgia Giant Cell Arteritis Glucocorticoid-induced Osteoperosis ...

  3. Nanodielectrics with giant permittivity

    S K Saha


    Nanodielectrics is an emerging area of research because of its potential application in energy storage and transducers. One-dimensional metallic nanostructures with localized electronic wave functions show giant dielectric constant. Following the prediction, during the last couple of years we have investigated the effect of giant permittivity in one-dimensional systems of conventional metals and conjugated polymer chains. In this article, we have tried to summarize the works on giant permittivity and finally the fabrication of nanocapacitor using metal nanowires, which shows giant permittivity is also discussed.

  4. Giant condyloma acuminatum of vulva

    S. M. Ramiz Ahmed


    Full Text Available In this paper, A 23 year old married woman who was diagnosed as a case of giant condyloma acuminatum of vulva measuring about 15 x 8 x 3 cm, irregular surface with multiple projections, oval in shape, firm to hard in consistency, mildly tender, exophytic, cauliflower like growth involving the whole vulva (lower part of mons pubis, labia, vestibule, clitoris, around vaginal opening. Another multiple small lesions were present at perineal region but there was no inguinal lymphadenopathy. She underwent a combined electro cauterization and cryotherapy for small to moderate size multiple primary and recurrent warty lesions and wide surgical excision with fasciocutaneous advancement flaps procedure for a giant lesions in the vulva. Excisional biopsies were performed to detect potential malignancy but malignancy was not found histologically. The patient was advised to first follow-up 1 month after operation when multiple small warty lesions were developed and treated and the subsequent follow-ups for 3 months.

  5. Evolution of Prolate Molecular Clouds at HII Boundaries: I. Formation of fragment-core structures

    Kinnear, Timothy M; White, Glenn J; Goodwin, Simon


    The evolution of a prolate cloud at an Hii boundary is investigated using Smoothed Particle Hydrodynamics (SPH). The prolate molecular clouds in our investigation are set with their semi-major axis perpendicular to the radiative direction of a plane parallel ionising Extreme Ultraviolet (EUV) flux. Simulations on three high mass prolate clouds reveal that EUV radiation can trigger distinctive high density core formation embedded in a final linear structure. This contrasts with results of the previous work in which only an isotropic Far Ultraviolet (FUV) interstellar background flux was applied. A systematic investigation on a group of prolate clouds of equal mass but different initial densities and geometric shapes finds that the distribution of the cores over the final linear structure changes with the initial conditions of the prolate cloud and the strength of the EUV radiation flux. These highly condensed cores may either scatter over the full length of the final linear structure or form two groups of high...

  6. HII 2407: A Low-Mass Eclipsing Binary Revealed by K2 Observations of the Pleiades

    David, Trevor J; Hillenbrand, Lynne A; Cody, Ann Marie; Conroy, Kyle; Stassun, Keivan G; Pope, Benjamin; Aigrain, Suzanne; Gillen, Ed; Cameron, Andrew Collier; Barrado, David; Rebull, L M; Isaacson, Howard; Marcy, Geoffrey W; Zhang, Celia; Riddle, Reed L; Ziegler, Carl; Law, Nicholas M; Baranec, Christoph


    The star HII 2407 is a member of the relatively young Pleiades star cluster and was previously discovered to be a single-lined spectroscopic binary. It is newly identified here within $Kepler$/$K2$ photometric time series data as an eclipsing binary system. Mutual fitting of the radial velocity and photometric data leads to an orbital solution and constraints on fundamental stellar parameters. While the primary has arrived on the main sequence, the secondary is still pre-main-sequence and we compare our results for the $M/M_\\odot$ and $R/R_\\odot$ values with stellar evolutionary models. We also demonstrate that the system is likely to be tidally synchronized. Follow-up infrared spectroscopy is likely to reveal the lines of the secondary, allowing for dynamically measured masses and elevating the system to benchmark eclipsing binary status.


    David, Trevor J.; Hillenbrand, Lynne A.; Zhang, Celia; Riddle, Reed L. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Stauffer, John; Rebull, L. M. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Cody, Ann Marie [NASA Ames Research Center, Mountain View, CA 94035 (United States); Conroy, Kyle; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Pope, Benjamin; Aigrain, Suzanne; Gillen, Ed [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Cameron, Andrew Collier [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Barrado, David [Centro de Astrobiología, INTA-CSIC, Dpto. Astrofísica, ESAC Campus, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Isaacson, Howard; Marcy, Geoffrey W. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Ziegler, Carl; Law, Nicholas M. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 (United States); Baranec, Christoph, E-mail: [Institute for Astronomy, University of Hawai‘i at Mānoa, Hilo, HI 96720-2700 (United States)


    The star HII 2407 is a member of the relatively young Pleiades star cluster and was previously discovered to be a single-lined spectroscopic binary. It is newly identified here within Kepler/K2 photometric time series data as an eclipsing binary system. Mutual fitting of the radial velocity and photometric data leads to an orbital solution and constraints on fundamental stellar parameters. While the primary has arrived on the main sequence, the secondary is still pre-main sequence and we compare our results for the M/M{sub ⊙} and R/R{sub ⊙} values with stellar evolutionary models. We also demonstrate that the system is likely to be tidally synchronized. Follow-up infrared spectroscopy is likely to reveal the lines of the secondary, allowing for dynamically measured masses and elevating the system to benchmark eclipsing binary status.

  8. High Circular Polarization in the Star Forming Region NGC 6334: Implications

    Ménard, François; Chrysostomou, A.; Gledhill, T.; Hough, J. H.; Bailey, J.

    The amino-acids which form the building blocks of biological proteins are all left-handed molecules. By contrast, when these molecules are made in the laboratory equal numbers of the right and left-handed versions are made. This homochirality found in biological material may then well be a prerequisite for the origin of life and a number of processes have been proposed to produce the required enantiomeric excess in prebiotic organic molecules. We report here on the detection of high degrees of circular polarisation in the star forming complex NGC 6334, in the constellation Scorpius. This important finding suggests the widespread nature of a potentially efficient process to produce biomolecules with large chiral excess, namely selective (asymmetric) photolysis by circularly polarised light. The mechanism, well known in the laboratory, was first suggested to take place in a star forming region by Bailey et al. (1998) (Science, 281, 672; and this conference), following our discovery of high degrees of near-infrared circular polarisation in the Orion molecular cloud, OMC-1. NGC 6334 is a giant HII region and molecular cloud similar to Orion. These two detections of large circular polarisation, among the small number of sources surveyed so far, lead us to suggest that selective photolysis by circular polarisation may be quite widespread in massive star formation regions.

  9. A spectral and photometric study of 102 star forming regions in seven spiral galaxies

    Gusev, A S; Piskunov, A E; Kharchenko, N V; Bruevich, V V; Ezhkova, O V; Guslyakova, S A; Lang, V; Shimanovskaya, E V; Efremov, Yu N


    We present a study of complexes of young massive star clusters (YMCs), embedded in extragalactic giant HII regions, based on the coupling of spectroscopic with photometric and spectrophotometric observations of about 100 star forming regions in seven spiral galaxies (NGC 628, NGC 783, NGC 2336, NGC 6217, NGC 6946, NGC 7331, and NGC 7678). The complete observational database has been observed and accumulated within the framework of our comprehensive study of extragalactic star forming regions. The current paper presents the last part of either unpublished or refreshed photometric and spectrophotometric observations of the galaxies NGC 6217, NGC 6946, NGC 7331, and NGC 7678. We derive extinctions, chemical abundances, continuum and line emissions of ionised gas, ages and masses for cluster complexes. We find the young massive cluster complexes to have ages no greater than 10 Myr and masses between 10^4Msol and 10^7Msol, and the extinctions A(V) vary between ~ 0 and 3 mag, while the impact of the nebular emissio...

  10. Granuloma reparativo de células gigantes agresivo en región mandibular Aggressive giant cells reparative granulomas in mandibular region

    Ernesto Sánchez Cabrales


    Full Text Available El granuloma reparativo de células gigantes (GRCG es un proceso reactivo agresivo, que aparece con mayor frecuencia en los sectores anteriores de la mandíbula y el maxilar, en niños y adolecentes jóvenes. Constituye el 1 % de las lesiones óseas tumorales. Existe una considerable controversia acerca de si son lesiones benignas o reactivas; también desde el punto de vista de su origen, de sus características clínicas e histológicas, así como su terapéutica. En octubre de 2007 acudió un caso a consulta externa de Cirugía Maxilofacial del Hospital Pediátrico Universitario "Juan M. Márquez", con una lesión diagnosticada como GRCG agresivo, la cual provocó gran deformidad facial y osteólisis del cuerpo mandibular. Se realizaron exámenes físicos, complementarios e iconopatográfico. Se ejecutó tratamiento quirúrgico y análisis de la pieza. La paciente no tuvo alteraciones estéticas ni funcionales. Hubo ausencia de recidiva, luego de 30 meses de seguimiento. Se revisó la literatura más reciente en los sitios Med Line, Lilac, Google, con las palabras clave granuloma reparativo de células gigantes, en inglés y español, para comparar nuestros procederes y resultados con otros reportes.The giant cells reparative granulomas (GCRG is a reactive and aggressive process appearing more frequently in anterior sector of mandible and maxilla in children and young adolescents accounting for the 1 % of tumor bone lesions. There is a considerable controversy if they are benign or reactive lesions from the point of view of its origin, from its clinical and histological features as well as therapeutical. This is the case of a patient seen in external consultation of Maxillofacial Surgery of the "Juán Manuel Márquez" Children and University Hospital at October, 2007 in whom an extent lesion diagnosed as an aggressive GCRG provoked a facial deformity and osteolysis of mandibular body. Complementary, physical and iconopathographic examinations

  11. Quantum Giant Magnons

    Zarembo, K


    The giant magnons are classical solitons of the O(N) sigma-model, which play an important role in the AdS/CFT correspondence. We study quantum giant magnons first at large N and then exactly using Bethe Ansatz, where giant magnons can be interpreted as holes in the Fermi sea. We also identify a solvable limit of Bethe Ansatz in which it describes a weakly-interacting Bose gas at zero temperature. The examples include the O(N) model at large N, weakly interacting non-linear Schrodinger model, and nearly isotropic XXZ spin chain in the magnetic field.

  12. Giant Cell Fibroma

    Tahere Nosratzehi; Lale Maleki


    Giant cell fibroma is a fibrous tumor which represents about 2 to 5% of all oral fibrotic proliferations. Compared to traumatic fibroma, giant (traumatic fibroma or irritation fibroma) cell fibroma occurs at a younger age. In about 60% of the cases the lesion is diagnosed within the first three decades of life and is slightly more in women. 50% of the cases is observed in the gum and will appear as a nodule with a papillary surface [1]. The giant cell fibroma is treated by conservative excisi...

  13. T-cell compartment involvement in two high antibody responder lines of mice (HI and HII Biozzi mice) respectively susceptible and resistant to collagen-induced arthritis.

    Lima, G C; Zyad, A; Decreusefond, C; Mevel, J C; Stiffel, C; Mouton, D; Couderc, J


    The T-cell compartment was investigated in two high antibody responder lines of mice respectively susceptible (HI) and resistant (HII) to chicken collagen (CII)-induced arthritis (CIA). Previous data had shown that both lines were high anti-CII Ab producers, without any TCR V-beta gene defect or membrane expression impairment. The present studies demonstrate that anti-CII proliferation is much lower in HII than in HI. These results are confirmed by the limiting dilution analysis of anti-CII T-precursor frequencies (1/991 in HI and 1/12175 in HII). The percentage of CD8+ T cells is constitutively higher in HII mice, this difference increasing after CII immunization. This finding suggests a suppressive effect accounting for resistance to CIA. However, no restoration of specific response was achieved by in-vivo or in-vitro depletion of CD8+ T cells. T clones specific for Chicken CII could be obtained only from primed HI mice. Four of five clones with CD8+ phenotype proliferated in vitro to native and denatured CII and showed cytotoxic function in an anti-CD3 redirected assay. The CD4+ clone was shown to proliferate on both HI and HII-pulsed APC, which rules out a major CII processing/presentation defect in HII.

  14. Giant distal humeral geode

    Maher, M.M. [Department of Radiology, Mater Misericordiae Hospital, Dublin (Ireland); Department of Radiology, St. Vincent' s Hospital, Elm Park, Dublin 4 (Ireland); Kennedy, J.; Hynes, D. [Department of Orthopaedics, Mater Misericordiae Hospital, Dublin (Ireland); Murray, J.G.; O' Connell, D. [Department of Radiology, Mater Misericordiae Hospital, Dublin (Ireland)


    We describe the imaging features of a giant geode of the distal humerus in a patient with rheumatoid arthritis, which presented initially as a pathological fracture. The value of magnetic resonance imaging in establishing this diagnosis is emphasized. (orig.)

  15. Metaphyseal giant cell tumor

    Pereira, L.F.; Hemais, P.M.P.G.; Aymore, I.L.; Carmo, M.C.R. do; Cunha, M.E.P.R. da; Resende, C.M.C.

    Three cases of metaphyseal giant cell tumor are presented. A review of the literature is done, demostrating the lesion is rare and that there are few articles about it. Age incidence and characteristics of the tumor are discussed.

  16. The Giant Cell.

    Stockdale, Dennis


    Provides directions for the construction of giant plastic cells, including details for building and installing the organelles. Also contains instructions for preparing the ribosomes, nucleolus, nucleus, and mitochondria. (DDR)

  17. Seismology of Giant Planets

    Gaulme, Patrick; Schmider, Francois-Xavier; Guillot, Tristan


    Seismology applied to giant planets could drastically change our understanding of their deep interiors, as it has happened with the Earth, the Sun, and many main-sequence and evolved stars. The study of giant planets' composition is important for understanding both the mechanisms enabling their formation and the origins of planetary systems, in particular our own. Unfortunately, its determination is complicated by the fact that their interior is thought not to be homogeneous, so that spectroscopic determinations of atmospheric abundances are probably not representative of the planet as a whole. Instead, the determination of their composition and structure must rely on indirect measurements and interior models. Giant planets are mostly fluid and convective, which makes their seismology much closer to that of solar-like stars than that of terrestrial planets. Hence, helioseismology techniques naturally transfer to giant planets. In addition, two alternative methods can be used: photometry of the solar light ref...

  18. Giant magnetostrictive materials

    LIU JingHua; JIANG ChengBao; XU HuiBin


    Giant magnetostrictive materials are a kind of functional materials developed since 1970s,known as their large magnetostrain and high energy density.In this paper,an introduction of magnetosttiction and the history of magnetostrictive materials are described firstly.Then we review the recent developments of both rare earth and non-rare earth magnetostrictive materials.Finally,the tendency of developing new giant magnetostrictive materials is presented.

  19. Red giant seismology: Observations

    Mosser B.


    Full Text Available The CoRoT and Kepler missions provide us with thousands of red-giant light curves that allow a very precise asteroseismic study of these objects. Before CoRoT and Kepler, the red-giant oscillation patterns remained obscure. Now, these spectra are much more clear and unveil many crucial interior structure properties. For thousands of red giants, we can derive from seismic data precise estimates of the stellar mass and radius, the evolutionary status of the giants (with a clear difference between clump and RGB stars, the internal differential rotation, the mass loss, the distance of the stars... Analyzing this amount of information is made easy by the identification of the largely homologous red-giant oscillation patterns. For the first time, both pressure and mixed mode oscillation patterns can be precisely depicted. The mixed-mode analysis allows us, for instance, to probe directly the stellar core. Fine details completing the red-giant oscillation pattern then provide further information on the interior structure, including differential rotation.

  20. Collisional excitation of hydrogen and the determination of the primordial helium abundance from H II regions

    Stasinska, G


    This paper investigates the effect of collisional enhancement of the hydrogen lines on the derivation of the helium abundances in low metallicity H II regions. For this, we have constructed a grid of photoionization models relevant for the analysis of giant \\hii regions in blue compact galaxies. We show that the effect of collisional excitation on the Halpha/Hbeta ratio can be quite important (up to 8% or more). The impact of this effect on the determination of the helium mass fraction has been tracked on four low-metallicity blue compact galaxies for which Keck spectra are available and which are among the best objects for the quest of the pregalactic helium abundance. We find that taking into account the effects of collisional excitation of hydrogen results in an upward correction of the helium mass fraction Y by up to 5%. However, combining with other systematic effects usually not considered in the determination of the helium abundance in low-metallicity galaxies, the resulting uncertainty should be much ...

  1. A Multi-molecular Line Study of an Entire Giant Molecular Cloud

    Lo, Nadia


    A unified theory of star formation remains one of the major unsolved issues in astrophysics. Presented here are the results of multi-molecular lines mapping of the entire giant molecular cloud G333, comprised sites of low- and high-mass star forming regions in various evolution stages of star formation. The result shows the spatial distribution of CS, HCO+, HCN and HNC are similar on large scales, while N2H+ seems to trace preferentially the very densest regions, possibly due to the chemical difference, that N2H+ is sensitive to temperature and readily destroyed by CO. Two analysis methods were used to characterise this large set of data cubes: GAUSSCLUMPS and principal component analysis (PCA). We found the clumps are heavily fragmented with a beam filling factor of 0.2. We found no correlation between clump radius and line width, contradicts to Larson's Law. Possible explanation is the clumps are fragmented and unresolved with the resolution of Mopra beam, thus the decomposed clump radius is blended and no physical properties can be interpreted. PCA of the velocity dimension found no significant differences among CS, HCO+, HNC and C2H line emissions, suggesting these four molecules are `well-mixed' on large scale, possibly by turbulence. PCA of the integrated emission maps separates molecules into low (13CO and C18O) and high (the rest) density tracers, identifies anti-correlation between HCO+ and N2H+ (due to the depletion of CO). The possibility of removing the scanning patterns of the `on-the-fly' mapping with PCA was also explored. The detection of broad thermal SiO from the massive dense cold core G333.125-0.562, along with other collected transitions, suggesting the core will host massive star formation and the SiO emission arises from shocks associated with an outflow in the cold core. Result of the modelling infall with 3D radiative transfer code using the derived physical parameters have successfully reproduce the line profiles. Recent observation of the

  2. Infrared spectral properties of M giants

    Sloan, G C; Ramirez, R M; Kraemer, K E; Engelke, C W


    We observed a sample of 20 M giants with the Infrared Spectrograph on the Spitzer Space Telescope. Most show absorption structure at 6.6-6.8 um which we identify as water vapor, and in some cases, the absorption extends from 6.4 um into the SiO band at 7.5 um. Variable stars show stronger H2O absorption. While the strength of the SiO fundamental at 8 um increases monotonically from spectral class K0 to K5, the dependence on spectral class weakens in the M giants. As with previously studied samples, the M giants show considerable scatter in SiO band strength within a given spectral class. All of the stars in our sample also show OH band absorption, most noticeably in the 14-17 um region. The OH bands behave much like the SiO bands, increasing in strength in the K giants but showing weaker dependence on spectral class in the M giants, and with considerable scatter. An examination of the photometric properties reveals that the V-K color may be a better indicator of molecular band strength than the spectral class...

  3. Disentangling the metallicity and star formation history of HII galaxies through tailor-made models

    Perez-Montero, Enrique; Hagele, Guillermo F; Diaz, Angeles I


    We present a self-consistent study of the stellar populations and the ionized gas in a sample of 10 HII galaxies with, at least, four measured electron temperatures and a precise determination of ionic abundances following the "direct method". We fitted the spectral energy distribution of the galaxies using the program STARLIGHT in order to quantify the contribution of the underlying stellar population to EW(Hbeta), which amounts to about 10% for most of the objects. We then studied the Wolf-Rayet stellar populations detected in seven of the galaxies. The presence of these populations and the corrected EW(Hbeta) values indicate that the ionizing stellar populations were created following a continuous star formation episode of 10 Myr duration, hence WR stars may be present in all of objects even if they are not detected in some of them. The derived stellar features, the number of ionizing photons and the relative intensities of the strongest emission lines were used as input parameters to compute tailored mode...

  4. Thermal Giant Gravitons

    Armas, Jay; Obers, Niels A; Orselli, Marta; Pedersen, Andreas Vigand


    We study the giant graviton solution as the AdS_5 X S^5 background is heated up to finite temperature. The analysis employs the thermal brane probe technique based on the blackfold approach. We focus mainly on the thermal giant graviton corresponding to a thermal D3-brane probe wrapped on an S^3 moving on the S^5 of the background at finite temperature. We find several interesting new effects, including that the thermal giant graviton has a minimal possible value for the angular momentum and correspondingly also a minimal possible radius of the S^3. We compute the free energy of the thermal giant graviton in the low temperature regime, which potentially could be compared to that of a thermal state on the gauge theory side. Moreover, we analyze the space of solutions and stability of the thermal giant graviton and find that, in parallel with the extremal case, there are two available solutions for a given temperature and angular momentum, one stable and one unstable. In order to write down the equations of mot...

  5. Rapidly rotating red giants

    Gehan, Charlotte; Michel, Eric


    Stellar oscillations give seismic information on the internal properties of stars. Red giants are targets of interest since they present mixed modes, which behave as pressure modes in the convective envelope and as gravity modes in the radiative core. Mixed modes thus directly probe red giant cores, and allow in particular the study of their mean core rotation. The high-quality data obtained by CoRoT and Kepler satellites represent an unprecedented perspective to obtain thousands of measurements of red giant core rotation, in order to improve our understanding of stellar physics in deep stellar interiors. We developed an automated method to obtain such core rotation measurements and validated it for stars on the red giant branch. In this work, we particularly focus on the specific application of this method to red giants having a rapid core rotation. They show complex spectra where it is tricky to disentangle rotational splittings from mixed-mode period spacings. We demonstrate that the method based on the id...

  6. Evolution of Chromospheric Activity: M67 Red Giants

    Dupree, A. K.; Whitney, B. A.; Pasquini, L.


    Echelle spectra of the Ca II H- and K-line region (λ3950) of 15 red giant stars in the open cluster M67 reveal atmospheric dynamics and determine chromospheric radiative losses in order to assess chromospheric heating requirements and to follow the evolution of chromospheric activity. M67 red giants in conjunction with giants in younger clusters create a continuous group of red giants in the color-magnitude diagram, with 0.1mass motions are well established at these luminosities. Radiative losses, as measured by emission strengths from Ca II, decrease smoothly with decreasing stellar effective temperature in M67 and connect well to a combined sample of warmer cluster giants (NGC 2477, IC 4756, and the Hyades) with Mrelated processes. The relative contribution of each heating mechanism changes with temperature in the stellar atmosphere, and these proportions may change during a star's evolution from the main sequence.

  7. The Schmidt-Kennicutt Law of Matched-Age Star Forming Regions; Pa-alpha Observations of the Early-Phase Interacting Galaxy Taffy I

    Komugi, S; Motohara, K; Takagi, T; Iono, D; Kaneko, H; Ueda, J; Saitoh, T R; Kato, N; Konishi, M; Koshida, S; Morokuma, T; Takahashi, H; Tanabe, T; Yoshii, Y


    In order to test a recent hypothesis that the dispersion in the Schmidt-Kennicutt law arises from variations in the evolutionary stage of star forming molecular clouds, we compared molecular gas and recent star formation in an early-phase merger galaxy pair, Taffy I (UGC\\ 12915/UGC\\ 12914, VV\\ 254) which went through a direct collision 20 Myr ago and whose star forming regions are expected to have similar ages. Narrow-band Pa-alpha image is obtained using the ANIR near-infrared camera on the mini-TAO 1m telescope. The image enables us to derive accurate star formation rates within the galaxy directly. The total star formation rate, 22.2 M_sun/yr, was found to be much higher than previous estimates. Ages of individual star forming blobs estimated from equivalent widths indicate that most star forming regions are ~7 Myr old, except for a giant HII region at the bridge which is much younger. Comparison between star formation rates and molecular gas masses for the regions with the same age exhibits a surprisingly...

  8. Giant star seismology

    Hekker, S


    The internal properties of stars in the red-giant phase undergo significant changes on relatively short timescales. Long near-interrupted high-precision photometric timeseries observations from dedicated space missions such as CoRoT and Kepler have provided seismic inferences of the global and internal properties of a large number of evolved stars, including red giants. These inferences are confronted with predictions from theoretical models to improve our understanding of stellar structure and evolution. Our knowledge and understanding of red giants have indeed increased tremendously using these seismic inferences, and we anticipate that more information is still hidden in the data. Unraveling this will further improve our understanding of stellar evolution. This will also have significant impact on our knowledge of the Milky Way Galaxy as well as on exo-planet host stars. The latter is important for our understanding of the formation and structure of planetary systems.

  9. Gemini GMOS--IFU spectroscopy of the compact HII galaxies Tol 0104-388 and Tol 2146-391: The dependence on the properties of the interstellar medium

    Lagos, P; Nigoche-Netro, A; Carrasco, E R


    Using GMOS--IFU spectroscopic observations of the compact HII/BCD galaxies Tol 0104-388 and Tol 2146-391, we study the spatial distribution of emission lines, equivalent width EW(Hb), extinction c(Hb), ionization ratios ([OIII]5007/Hb, [SII]6717,6731/Ha and [NII]6584/Ha), kinematics, and the chemical pattern (O/H, N/H and N/O) of the warm interstellar medium in these galaxies. We also investigate a possible dependence of these properties on the I(HeII4686)/I(Hb) ratio and find no significant correlation between these variables. In fact, the oxygen abundances appear to be uniform in the regions where the HeII4686 emission line was measured. It can be interpreted in the sense that these correlations are related to global properties of the galaxies and not with small patches of the interstellar medium. Although a possible weak N/H gradient is observed in Tol 2146-391, the available data suggest that the metals from previous star-formation events are well mixed and homogeneously distributed through the optical ex...

  10. Star forming regions in gas-rich SO galaxies

    Pogge, Richard W.; Eskridge, Paul B.


    The first results of an H alpha imaging survey of HI rich SO galaxies, which were searched for HII regions and other sources of emission, are presented. The charge coupled device H alpha interference filter images were made of 16 galaxies. Eight of these galaxies show evidence for on-going star formation, one has nuclear emission but no HII regions, and the remaining seven have no emissions detected within well defined upper limits. With the exception of one notably peculiar galaxy in which the emission from HII regions appears pervasive, the HII regions are either organized into inner-disk rings or randomly distributed throughout the disk. A few of these galaxies are found to be clearly not SO's; or peculiar objects atypical of the SO class. Using simple models star formation rates (SFRs) and gas depletion times from the observed H alpha fluxes were estimated. In general, the derived SFRs are much lower than those found in isolated field spiral galaxies and the corresponding gas depletion time scales are also longer.

  11. Surgical excision of the breast giant fibroadenoma under regional anesthesia by Pecs II and internal intercostal plane block: a case report and brief technical description: a case report.

    Kim, Hyungtae; Shim, Junho; Kim, Ikthae


    A 22-years-old female patient at 171 cm and 67 kg visited the Department of Breast Surgery of the hospital with a mass accompanied with pain on the left side breast as chief complaints. Since physical examination revealed a suspected huge mass, breast surgeon decided to perform surgical excision and requested anesthesia to our department. Surgery of breast tumor is often under local anesthesia. However, in case of big size tumor, surgery is usually performed under general anesthesia. The patient feared general anesthesia. Unlike abdominal surgery, there is no need to control visceral pain for breast and anterior thoracic wall surgery. Therefore, we decided to perform resection under regional anesthesia. Herein, we report a successful anesthetic and pain management of the patient undergoing excision of a huge breast fibroadenoma under regional anesthesia using Pecs II and internal intercostal plane block.

  12. MUSCLE W49 : A Multi-Scale Continuum and Line Exploration of the Most Luminous Star Formation Region in the Milky Way. I. Data and The Mass Structure of the Giant Molecular Cloud

    Galvan-Madrid, R; Zhang, Z -Y; Pineda, J E; Peng, T -C; Zhang, Q; Keto, E R; Ho, P T P; Rodriguez, L F; Zapata, L; Peters, T; De Pree, C G; .,


    The Multi-Scale Continuum and Line Exploration of W49 (MUSCLE W49) is a comprehensive gas and dust survey of the parental giant molecular cloud (GMC) of W49A, the most luminous (L~10^7 Lsun) star-formation region in the Milky Way. Observations cover the entire GMC at different scales and angular resolutions. In this paper we present: 1) a multiconfiguration SMA mosaic covering the central ~3x3 arcmin (~10 pc, known as W49N), where most of the embedded massive stars reside; and 2) PMO-14m observations covering the entire GMC with maps of up to ~35x35 arcmin in size (~113 pc). We also make use of archival data from the VLA, JCMT-SCUBA, IRAM 30m, and the CSO BOLOCAM Galactic Plane Survey. Our main findings are: 1) The W49 GMC is one of the most massive in the Galaxy with a total mass Mgas~1.1x10^6 Msun within a radius of 60 pc, and Mgas~2x10^5 Msun within a radius of 6 pc. The W49 GMC has a mass reservoir sufficient to form several young massive clusters (YMCs), or even a globular cluster. 2) The mass of the GMC...

  13. Massive envelopes and filaments in the NGC 3603 star forming region

    Hummel, C A; Galvan-Madrid, R; Koribalski, B S


    The formation of massive stars and their arrival on the zero-age main-sequence occurs hidden behind dense clouds of gas and dust. In the giant Hii region NGC 3603, the radiation of a young cluster of OB stars has dispersed dust and gas in its vicinity. At a projected distance of 2:5 pc from the cluster, a bright mid-infrared (mid-IR) source (IRS 9A) had been identified as a massive young stellar object (MYSO), located on the side of a molecular clump (MM2) of gas facing the cluster. We investigated the physical conditions in MM2, based on APEX sub-mm observations using the SABOCA and SHFI instruments, and archival ATCA 3 mm continuum and CS spectral line data. We resolved MM2 into several compact cores, one of them closely associated with IRS 9A. These are likely infrared dark clouds as they do not show the typical hot-core emission lines and are mostly opaque against the mid-IR background. The compact cores have masses of up to several hundred times the solar mass and gas temperatures of about 50 K, without ...

  14. Juvenile giant fibroadenoma

    Vipul Yagnik


    Full Text Available Fibroadenomas are benign solid tumor associated with aberration of normal lobular development. Juvenile giant fibroadenoma is usually single and >5 cm in size /or >500 gms in weight. Important differential diagnoses are: phyllodes tumor and juvenile gigantomastia. Simple excision is the treatment of choice.

  15. [Giant retroperitoneal liposarcoma].

    Mezzour, Mohamed Hicham; El Messaoudi, Yasser Arafat; Fekak, Hamid; Rabii, Redouane; Marnissi, Farida; Karkouri, Mehdi; Salam, Siham; Iraki, Moulay Ahmed; Joual, Abdenbi; Meziane, Fathi


    The authors report a case of giant retroperitoneal liposarcoma. The diagnosis was suspected after scanography and magnetic resonance imaging and confirmed by the histological analysis of the extracted piece after surgical treatment. Postoperative evolution was favourable after one year without recurrence or distant metastasis. The authors discuss the pathologic and therapeutic aspects and the prognosis of retroperitoneal liposarcoma.

  16. Giant Congenital Melanocytic Nevus

    Rasmussen, Bo Sonnich; Henriksen, Trine Foged; Kølle, Stig-Frederik Trojahn


    Giant congenital melanocytic nevi (GCMN) occur in 1:20,000 livebirths and are associated with increased risk of malignant transformation. The treatment of GCMN from 1981 to 2010 in a tertiary referral center was reviewed evaluating the modalities used, cosmetic results, associated complications...

  17. Waking the Sleeping Giant

    Ollenburger, Mary H.; Descheemaeker, Katrien; Crane, Todd A.; Sanogo, Ousmane M.; Giller, Ken E.


    The World Bank argued that West Africa's Guinea Savannah zone forms part of “Africa's Sleeping Giant,” where increases in agricultural production could be an engine of economic growth, through expansion of cultivated land in sparsely populated areas. The district of Bougouni, in southern Mali,

  18. Sequence variation and genetic diversity in the giant panda

    张亚平; Oliver A.Ryder; 范志勇; 张和明; 何廷美; 何光昕; 张安居; 费立松; 钟顺隆; 陈红; 张成林; 杨明海; 朱飞兵; 彭真信; 普天春; 陈玉村; 姚敏达; 郭伟


    About 336-444 bp mitochondrial D-loop region and tRNA gene were sequenced for 40 individuals of the giant panda which were collected from Mabian, Meigu, Yuexi, Baoxing, Pingwu, Qingchuan, Nanping and Baishuijiang, respectively. 9 haplotypes were found in 21 founders. The results showed that the giant panda has low genetic variations, and that there is no notable genetic isolation among geographical populations. The ancestor of the living giant panda population perhaps appeared in the late Pleistocene, and unfortunately, might have suffered bottle-neck attacks. Afterwards, its genetic diversity seemed to recover to some extent.

  19. Propiedades físicas del gas en regiones de formación estelar multiples en galaxias BCDs: IIZw33 y Mrk600

    Campuzano-Castro, F.; Hagele, G.; Cardaci, M.; Bosch, G.; Firpo, V.


    In this work we perform a detailed analysis of the spectra of the ionized gas belonging to 9 giant HII regions with violent star formation in two Blue Compact Dwarf galaxies. We have measured a large number of recombination and forbidden lines taking into account the underlying stellar population (defining a pseudo continuum for the hydrogen and helium emission lines). The physical properties of the gas have been estimated using the methodology proposed by our group. For the star forming knots, depending on the data available, we derived: (i) the reddening constant from the hydrogen recombination lines in all the regions, (ii) the electron density in the low excitation zone from the sulphur once ionized [SII]6717 and 6731 emission lines ratio, (iii) the electron temperatures using the auroral lines present in the spectra of several of our regions and applying the direct method or empirical relations and photo ionization models: T([OII]), T([OIII]), T([SII]), T([SIII])], and T([NII]) depending on the quality of the spectra, (iv) ionic abundances of He, O, O, S, S, N, Ne, Ar and Ar in most of the knots, except the last one that could only be measured for one object, (v) the total chemical abundances of O, S, N, Ne and Ar, (vi) the ionization degree from the softness parameter .

  20. MS_RHII-RSD, a dual-function RNase HII-(p)ppGpp synthetase from Mycobacterium smegmatis.

    Murdeshwar, Maya S; Chatterji, Dipankar


    In the noninfectious soil saprophyte Mycobacterium smegmatis, intracellular levels of the stress alarmones guanosine tetraphosphate and guanosine pentaphosphate, together termed (p)ppGpp, are regulated by the enzyme Rel(Msm). This enzyme consists of a single, bifunctional polypeptide chain that is capable of both synthesizing and hydrolyzing (p)ppGpp. The rel(Msm) knockout strain of M. smegmatis (Δrel(Msm)) is expected to show a (p)ppGpp null [(p)ppGpp(0)] phenotype. Contrary to this expectation, the strain is capable of synthesizing (p)ppGpp in vivo. In this study, we identify and functionally characterize the open reading frame (ORF), MSMEG_5849, that encodes a second functional (p)ppGpp synthetase in M. smegmatis. In addition to (p)ppGpp synthesis, the 567-amino-acid-long protein encoded by this gene is capable of hydrolyzing RNA·DNA hybrids and bears similarity to the conventional RNase HII enzymes. We have classified this protein as actRel(Msm) in accordance with the recent nomenclature proposed and have named it MS_RHII-RSD, indicating the two enzymatic activities present [RHII, RNase HII domain, originally identified as domain of unknown function 429 (DUF429), and RSD, RelA_SpoT nucleotidyl transferase domain, the SYNTH domain responsible for (p)ppGpp synthesis activity]. MS_RHII-RSD is expressed and is constitutively active in vivo and behaves like a monofunctional (p)ppGpp synthetase in vitro. The occurrence of the RNase HII and (p)ppGpp synthetase domains together on the same polypeptide chain is suggestive of an in vivo role for this novel protein as a link connecting the essential life processes of DNA replication, repair, and transcription to the highly conserved stress survival pathway, the stringent response.

  1. Literature review of giant gartersnake (Thamnophis gigas) biology and conservation

    Halstead, Brian J.; Wylie, Glenn D.; Casazza, Michael L.


    This report reviews the available literature on giant gartersnakes (Thamnophis gigas) to compile existing information on this species and identify knowledge gaps that, if addressed, would help to inform conservation efforts for giant gartersnakes.  Giant gartersnakes comprise a species of semi-aquatic snake precinctive to wetlands in the Central Valley of California.  The diversion of surface water and conversion of wetlands to agricultural and other land uses resulted in the loss of more than 90 percent of natural giant gartersnake habitats.  Because of this habitat loss, giant gartersnakes are now listed by the United States and California Endangered Species Acts as Threatened.  Most extant populations occur in the rice-growing regions of the Sacramento Valley, which comprises the northern portion of the giant gartersnake’s former range.  The huge demand for water in California for agriculture, industry, recreation, and other human consumption, combined with periodic severe drought, places remaining giant gartersnake habitats at increased risk of degradation and loss.  This literature review summarizes the available information on giant gartersnake distribution, habitat relations, behavior, demography, and other aspects of its biology relevant to conservation.  This information is then compiled into a graphical conceptual model that indicates the importance of different aspects of giant gartersnake biology for maintaining positive population growth, and identifies those areas for which important information relevant for conservation is lacking.  Directing research efforts toward these aspects of giant gartersnake ecology will likely result in improvements to conserving this unique species while meeting the high demands for water in California.

  2. Giant sialocele following facial trauma.

    Medeiros Júnior, Rui; Rocha Neto, Alípio Miguel da; Queiroz, Isaac Vieira; Cauby, Antônio de Figueiredo; Gueiros, Luiz Alcino Monteiro; Leão, Jair Carneiro


    Injuries in the parotid and masseter region can cause serious impairment secondary to damage of important anatomical structures. Sialocele is observed as facial swelling associated with parotid duct rupture due to trauma. The aim of this paper is to report a case of a giant traumatic sialocele in the parotid gland, secondary to a knife lesion in a 40-year-old woman. Conservative measures could not promote clinical resolution and a surgical intervention for the placement of a vacuum drain was selected. Under local anesthesia, a small incision was performed adjacent to parotid duct papilla, followed by muscular divulsion and draining of significant amount of saliva. An active vacuum suction drain was placed for 15 days, aiming to form a new salivary duct. This technique was shown to be a safe, effective and low-cost option, leading to complete resolution and no recurrence after 28 months of follow up.


    L. Grimaldi


    Full Text Available Giant genital warts (GGW represent a rare form of sexually transmitted disease caused by the human papillomavirus, arising more frequently in the vulvar and perianal regions as large exophytic cauliflower-like mass. Estimated rate of recurrence is 60 to 66%, while malignant transformation is possible and it has been reported in 30 to 56% of cases. A 45- years-old woman was admitted to our Structure of Plastic and Reconstructive Surgery, Siena, Italy with an extensive cauliflower- like masses diffused on vulvar and perianal region. The patient was treated in general anaesthesia, with a wide en bloc excision up to free clinical edges and immediate reconstruction of the vulvar continuity. Buschke Lowenstein tumour or giant genital warts is a sporadic tumour with an elevate local recurrence rate. In some cases, surgery can be very difficult and it must be associated to other strategies. An accurate follow-up is always necessary

  4. An Optical and Infrared Photometric Study of the Young Open Cluster IC 1805 in the Giant H ii Region W4 †

    Sung, Hwankyung; Bessell, Michael S.; Chun, Moo-Young; Yi, Jonghyuk; Nazé, Y.; Lim, Beomdu; Karimov, R.; Rauw, G.; Park, Byeong-Gon; Hur, Hyeonoh


    We present deep wide-field optical CCD photometry and mid-infrared Spitzer/IRAC and MIPS 24 μm data for about 100,000 stars in the young open cluster IC 1805. The members of IC 1805 were selected from their location in the various color-color and color-magnitude diagrams, and the presence of Hα emission, mid-infrared excess emission, and X-ray emission. The reddening law toward IC 1805 is nearly normal (R V = 3.05 ± 0.06). However, the distance modulus of the cluster is estimated to be 11.9 ± 0.2 mag (d=2.4+/- 0.2 kpc) from the reddening-free color-magnitude diagrams, which is larger than the distance to the nearby massive star-forming region W3(OH) measured from the radio VLBA astrometry. We also determined the age of IC 1805 ({τ }{MSTO}=3.5 Myr). In addition, we critically compared the age and mass scale from two pre-main-sequence evolution models. The initial mass function with a Salpeter-type slope of Γ = -1.3 ± 0.2 was obtained and the total mass of IC 1805 was estimated to be about 2700 ± 200 {M}⊙ . Finally, we found our distance determination to be statistically consistent with the Tycho-Gaia Astrometric Solution Data Release 1, within the errors. The proper motion of the B-type stars shows an elongated distribution along the Galactic plane, which could be explained by some of the B-type stars being formed in small clouds dispersed by previous episodes of star formation or supernova explosions. The optical imaging data in this article were gathered with two facilities: the AZT-22 1.5 m telescope at Maidanak Astronomical Observatory in Uzbekistan and the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  5. Asteroseismic age determination for dwarfs and giants

    Aguirre, V Silva


    Asteroseismology can make a substantial contribution to our understanding of the formation history and evolution of our Galaxy by providing precisely determined stellar properties for thousands of stars in different regions of the Milky Way. We present here the different sets of observables used in determining asteroseismic stellar properties, the typical level of precision obtained, the current status of results for ages of dwarfs and giants and the improvements than can be expected in the near future in the context of Galactic archaeology.

  6. Globally intertwined evolutionary history of giant barrel sponges

    Swierts, Thomas; Peijnenburg, Katja T. C. A.; de Leeuw, Christiaan A.; Breeuwer, Johannes A. J.; Cleary, Daniel F. R.; de Voogd, Nicole J.


    Three species of giant barrel sponge are currently recognized in two distinct geographic regions, the tropical Atlantic and the Indo-Pacific. In this study, we used molecular techniques to study populations of giant barrel sponges across the globe and assessed whether the genetic structure of these populations agreed with current taxonomic consensus or, in contrast, whether there was evidence of cryptic species. Using molecular data, we assessed whether giant barrel sponges in each oceanic realm represented separate monophyletic lineages. Giant barrel sponges from 17 coral reef systems across the globe were sequenced for mitochondrial (partial CO1 and ATP6 genes) and nuclear (ATPsβ intron) DNA markers. In total, we obtained 395 combined sequences of the mitochondrial CO1 and ATP6 markers, which resulted in 17 different haplotypes. We compared a phylogenetic tree constructed from 285 alleles of the nuclear intron ATPsβ to the 17 mitochondrial haplotypes. Congruent patterns between mitochondrial and nuclear gene trees of giant barrel sponges provided evidence for the existence of multiple reproductively isolated species, particularly where they occurred in sympatry. The species complexes in the tropical Atlantic and the Indo-Pacific, however, do not form separate monophyletic lineages. This rules out the scenario that one species of giant barrel sponge developed into separate species complexes following geographic separation and instead suggests that multiple species of giant barrel sponges already existed prior to the physical separation of the Indo-Pacific and tropical Atlantic.

  7. He i in the central giant H ii region of NGC 5253. A 2D observational approach to collisional and radiative transfer effects

    Monreal-Ibero, A.; Walsh, J. R.; Westmoquette, M. S.; Vílchez, J. M.


    -Rayet (WR) stars in the main GH iiR. Data are marginally consistent with an excess in the N/He ratio in the nitrogen-enriched area. This excess would be close to both the atmospheric N/He ratios in WR stars and the uncertainties estimated for the N/He ratios. We explored the influence of the kinematics in the evaluation of the He i radiative transfer effects. Our data empirically support the use of the traditional assumption that motions in an extragalactic H ii region have a negligible effect in the estimation of the global optical depths. Individually, the broad kinematic component (associated with an outflow) is affected by radiative transfer effects in a much more significant way than the narrow one. We find a relation between the amount of extra nitrogen and the upper limit of the contribution from radiative transfer effects that requires further investigation. We suggest that the electron temperature could be a common agent causing this relation. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (ESO Programme 078.B-0043 and 383.B-0043) and at the Gemini South Telescope (Programme GS-2008A-Q-25).

  8. The temperature and ionization structure of the emitting gas in HII galaxies: Implications for the accuracy of abundance determinations

    Hägele, G F; Díaz, A I; Terlevich, E; Terlevich, R J; Haegele, Guillermo F.; Perez-Montero, Enrique; Diaz, Angeles I.; Terlevich, Elena; Terlevich, Roberto


    We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the production and calibration of empirical relations between the different line temperatures that should superseed currently used ones based on very simple, and poorly tested, photo-ionization model sequences. As a first step to reach these goals we have obtained simultaneous blue to far red longslit spectra with the William Herschel Telescope (WHT) of three compact HII galaxies selected from the Sloan Digital Sky Survey (SDSS) Data Release 2 (DR2) spectral catalog using the INAOE Virtual Observatory superserver. Our spectra cover the range from 3200 to 10500 \\AA, including the Balmer jump, the [OII]3727,29 \\AA lines, the [SIII]9069,9532 \\AA doublet as well as various weak auroral lines such as [OIII]4363 \\AA and [SIII]6312 \\AA. For the three objects we have measured at least four line...


    M. Tapia


    Full Text Available The bright nebular complex NGC 6334 contains some of the most active sites of massive star formation known in our Galaxy. It is located at a distance from the Sun of 1.62 kpc and has a total mass of a few 105M . The physical characteristics of the active spots range widely, from well developed expanding HII regions to deeply embedded, still contracting, young objects detected only as millimeter sources, thus at their earliest observable stage of their evolution. The oldest optically visible round HII regions with central O-type stars are found in the southern parts, and the youngest along a molecular ridge. On the latter, no clear spatial evolutionary correlation is apparent.

  10. Giant Cell Arteritis.

    Hoffman, Gary S


    This issue provides a clinical overview of giant cell arteritis, focusing on diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

  11. Intraoral giant condyloma acuminatum

    Gupta R


    Full Text Available A case of intraoral giant condyloma acuminatum is reported in a 50- year- old Indian. He did not respond to topical application of podophyllin 20% but responded partially to electric cauterisation. Surgical excision was done to get rid of the warty growh completely. Since there were no skin or genital lesions and no history of marital or extramarital sexual contact the lesion was probably acquired from environmental sources. Nonsexual transmission should be considered especially when the lesions are extragenital.

  12. Giant Otters in Peru

    Schenk C.


    Full Text Available We are in the second year of fieldwork surveying for Giant Otters in the southeastern rainforest of Peru, in three areas with differing levels of legal protection. While there is some illegal hunting still happening outside the protected areas, the main threat to the otters is badly-conducted tourism. Well-organised tourism can be a promising argument for establishing protected areas like national parks.

  13. A giant graviton genealogy

    Lozano, Yolanda; Prinsloo, Andrea


    In this article we extend the construction of giant gravitons from holomorphic surfaces [arXiv:hep-th/0010206] to the ABJM correspondence. We construct a new class of 1/6-BPS M5-branes wrapping 5-manifolds in S^7/Z_k and supported by a large angular momentum in the orbifold space. These orbifold giant gravitons undergo a supersymmetry enhancement to 1/3-BPS and 1/2-BPS configurations in special cases. The compactification of M-theory on AdS_4 x S^7/Z_k to type IIA superstring theory on AdS_4 x CP^3 then gives rise to another new class of 1/6-BPS D4 and NS5-branes wrapping 4 and 5-manifolds in CP^3. The D4-branes carry a combination of D0-brane charge and angular momentum in the complex projective space, while the NS5-branes are supported only by D0-brane charge. Finally, we present a detailed analysis of a one-parameter family of 1/2-BPS M5-brane orbifold giant gravitons, and their D4 and NS5-brane CP^3 descendants.

  14. Giant prolactinomas in women

    Delgrange, Etienne; Raverot, Gerald; Bex, Marie


    OBJECTIVE: To characterise distinctive clinical features of giant prolactinomas in women. DESIGN: A multicentre, retrospective case series and literature review. METHODS: We collected data from 15 female patients with a pituitary tumour larger than 4 cm and prolactin levels above 1000 μg/l and id......OBJECTIVE: To characterise distinctive clinical features of giant prolactinomas in women. DESIGN: A multicentre, retrospective case series and literature review. METHODS: We collected data from 15 female patients with a pituitary tumour larger than 4 cm and prolactin levels above 1000 μg....../l and identified 19 similar cases from the literature; a gender-based comparison of the frequency and age distribution was obtained from a literature review. RESULTS: The initial PubMed search using the term 'giant prolactinomas' identified 125 patients (13 women) responding to the inclusion criteria. The female......:male ratio was 1:9. Another six female patients were found by extending the literature search, while our own series added 15 patients. The median age at diagnosis was 44 years in women compared with 35 years in men (Pwomen (n=34), we...

  15. A Diagnostic for Localizing Red Giant Differential Rotation

    Klion, Hannah


    We present a simple diagnostic that can be used to constrain the location of the differential rotation in red giants with measured mixed mode rotational splittings. Specifically, in red giants with radii $\\sim 4R_\\odot$, the splittings of p-dominated modes (sound wave dominated) relative to those of g-dominated modes (internal gravity wave dominated) are sensitive to how much of the differential rotation resides in the outer convection zone versus the radiative interior of the red giant. An independently measured surface rotation rate significantly aids breaking degeneracies in interpreting the measured splittings. We apply our results to existing observations of red giants, particularly those of Kepler-56, and find that most of the differential rotation resides in the radiative region rather than in the convection zone. This conclusion is consistent with results in the literature from rotational inversions, but our results are insensitive to some of the uncertainties in the inversion process and can be readi...

  16. Giant bullae mimicking tension pneumothorax

    Ahmet Erbey


    Full Text Available Giant bullae may mimic tension pneumothorax radiologicallyso that it may expand completely to hemithorax,increase of radiolucency mediastinal shift, flattening ofdiaphragm and printing on trachea. Sixty one year oldmale patient with giant bullae misdiagnosed as tensionpneumothorax and underwent to tube thoracostomy. Thedifferential diagnosis of giant bullae and tension pneumothoraxmay be confusing. The therapeutic approaches ofthese two radiologically similar entities differ significantly.Thus proper physical assessment and radiological examinationis crucial in the differential diagnosis and computedtomography examination should be performed before theadjustment of therapy. J Clin Exp Invest 2012; 3(4: 548-551Key words: Tension pneumothorax, giant bullae, computedtomography, tube thoracostomy

  17. MUSCLE W49: A multi-scale continuum and line exploration of the most luminous star formation region in the Milky Way. I. Data and the mass structure of the giant molecular cloud

    Galván-Madrid, R.; Pineda, J. E.; Peng, T.-C. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany); Liu, H. B.; Ho, P. T. P. [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China); Zhang, Z.-Y. [Max-Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Zhang, Q.; Keto, E. R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rodríguez, L. F.; Zapata, L. [Centro de Radioastronomía y Astrofísica, UNAM, A.P. 3-72 Xangari, Morelia 58089 (Mexico); Peters, T. [Institut für Theoretische Physik, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); De Pree, C. G. [Department of Physics and Astronomy, Agnes Scott College, Decatur, GA 30030 (United States)


    The Multi-scale Continuum and Line Exploration of W49 is a comprehensive gas and dust survey of the giant molecular cloud (GMC) of W49A, the most luminous star-formation region in the Milky Way. The project covers, for the first time, the entire GMC at different scales and angular resolutions. In this paper, we present (1) an all-configuration Submillimeter Array mosaic in the 230 GHz (1.3 mm) band covering the central ∼3' × 3' (∼10 pc, known as W49N), where most of the embedded massive stars reside and (2) Purple Mountain Observatory 14 m telescope observations in the 90 GHz band, covering the entire GMC with maps of up to ∼35' × 35' in size, or ∼113 pc. We also make use of archival data from the Very Large Array, JCMT-SCUBA, the IRAM 30 m telescope, and the Caltech Submillimeter Observatory BOLOCAM Galactic Plane Survey. We derive the basic physical parameters of the GMC at all scales. Our main findings are as follows. (1) The W49 GMC is one of the most massive in the Galaxy, with a total mass M {sub gas} ∼ 1.1 × 10{sup 6} M {sub ☉} within a radius of 60 pc. Within a radius of 6 pc, the total gas mass is M {sub gas} ∼ 2 × 10{sup 5} M {sub ☉}. At these scales, only ∼1% of the material is photoionized. The mass reservoir is sufficient to form several young massive clusters (YMCs) as massive as a globular cluster. (2) The mass of the GMC is distributed in a hierarchical network of filaments. At scales <10 pc, a triple, centrally condensed structure peaks toward the ring of HC H II regions in W49N. This structure extends to scales from ∼10 to 100 pc through filaments that radially converge toward W49N and its less-prominent neighbor W49S. The W49A starburst most likely formed from global gravitational contraction with localized collapse in a 'hub-filament' geometry. (3) Currently, feedback from the central YMCs (with a present mass M {sub cl} ≳ 5 × 10{sup 4} M {sub ☉}) is still not enough to entirely disrupt

  18. Using the VLT to analyze the compact photoionized regions in NGC 3109

    M. Peña


    Full Text Available Veinte nebulosas planetarias (NP y numerosas regiones HII compactas fueron detectadas en la galaxia irregular NGC3109, mediante imágenes \\en-línea" y \\fuera de línea" en [O III] 5007 obtenidas con el ESO VLT. Las NPs fueron seleccionadas como objetos estelares que no mostraran continuo estelar. Espectroscopia obtenida con el VLT FORS1 en modo multi-objeto ha permitido confirmar la naturaleza de NP para varias candidatas. Se ha obtenido también espectroscopia para varias regiones HII compactas. Los espectros son profundos de manera que muchos objetos muestran [O III] 4363 y se puede determinar la temperatura de las regiones, permitiendo analizar la composición química de NPs y regiones HII. Encontramos que las regiones HII muestran una composición química (O/H muy homogénea (en promedio 12 + log O/H = 7.79_0.10, en tanto que las NPs muestran variaciones grandes de composición química y un aparente enriquecimiento en oxígeno.

  19. Convection and Mixing in Giant Planet Evolution

    Vazan, Allona; Kovetz, Attay; Podolak, Morris


    The primordial internal structures of gas giant planets are unknown. Often giant planets are modeled under the assumption that they are adiabatic, convective, and homogeneously mixed, but this is not necessarily correct. In this work, we present the first self-consistent calculation of convective transport of both heat and material as the planets evolve. We examine how planetary evolution depends on the initial composition and its distribution, whether the internal structure changes with time, and if so, how it affects the evolution. We consider various primordial distributions, different compositions, and different mixing efficiencies and follow the distribution of heavy elements in a Jupiter-mass planet as it evolves. We show that a heavy-element core cannot be eroded by convection if there is a sharp compositional change at the core-envelope boundary. If the heavy elements are initially distributed within the planet according to some compositional gradient, mixing occurs in the outer regions resulting in a...

  20. Giant radio galaxies and cosmic web

    Heinämäki, Pekka


    Giant radio galaxies create the welldistinguishable class of sources.These sources are characterized with edge-brightened radio lobes withhighly collimated radio jets and large linear sizes which make themthe largest individual structures in the Universe. They are also knownto be hosted by elliptical/disturbed host galaxies and avoid clustersand high galaxy density regions. Because of GRG, large linear sizeslobes extend well beyond the interstellar media and host galaxyhalo the evolution of the radio lobes may depend on interactionwith this environment. Using our method to extract filamentarystructure of the galaxies in our local universe we study whetherradio lobe properties in some giant radio galaxies are determinedon an interaction of this filament ambient.


    Ashutosh Agrawal


    Full Text Available The peripheral giant cell granuloma (PGCG is a benign inflammatory hyperplastictype of lesion of unknown etiology occurring in gingiva or alveolar ridge. It normally presentsas a soft tissue purplish-red nodule consisting of multinucleated giant cells in a background ofmononuclear stromal cells and extravasated red blood cells. A 75 years old male patientreported with a chief complaint of pain and swelling in lower right back region of mouth. Onintra-oral examination the swelling was red, firm and sessile with smooth surface texture. Theorthopantomogram (OPG revealed a well-demarcated radiolucency extending from distalaspect of mandibular canine to mesial aspect of mandibular first molar. The cone beamcomputed tomography also showed the features suggestive of soft tissue lesion causingcupping resorption of mandible. Excisional biopsy was performed under local anaesthesiaand tissue was examined histopathologically. The lesion was diagnosed as PGCG afterthorough clinical, radiologic and histopathologic examination.

  2. Imaging Extrasolar Giant Planets

    Bowler, Brendan P.


    High-contrast adaptive optics (AO) imaging is a powerful technique to probe the architectures of planetary systems from the outside-in and survey the atmospheres of self-luminous giant planets. Direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high-order AO systems, dedicated planet-finding instruments with specialized coronagraphs, and innovative observing and post-processing strategies to suppress speckle noise. This review summarizes recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments. I conclude with a statistical meta-analysis of deep imaging surveys in the literature. Based on observations of 384 unique and single young (≈5-300 Myr) stars spanning stellar masses between 0.1 and 3.0 M ⊙, the overall occurrence rate of 5-13 M Jup companions at orbital distances of 30-300 au is {0.6}-0.5+0.7 % assuming hot-start evolutionary models. The most massive giant planets regularly accessible to direct imaging are about as rare as hot Jupiters are around Sun-like stars. Dividing this sample into individual stellar mass bins does not reveal any statistically significant trend in planet frequency with host mass: giant planets are found around {2.8}-2.3+3.7 % of BA stars, planets spanning a broad range of masses and ages.

  3. Giant aerosol observations with cloud radar: methodology and effects

    Guma Claramunt, Pilar; Madonna, Fabio; Amodeo, Aldo; Bauer-Pfundstein, Matthias; Papagiannopoulos, Nikolaos; Pappalardo, Gelsomina


    Giant aerosol particles can act as Giant Cloud Condensation Nuclei (GCCN), and determine the droplet concentration at the cloud formation, the clouds albedo and lifetime, and the precipitation formation. In addition, depending on their composition, they can also act as IN. It is not yet clear if they can also expedite rain processes. The main techniques used nowadays in measuring aerosols, which are lidar and sun photometer, cannot retrieve aerosol microphysical properties for particles bigger than a few microns, which means that they do not account for giant aerosols. Therefore, the distribution and impact in the atmosphere and climate of these particles is not well known and the aerosol transport models largely underestimate them. Recent studies have demonstrated that cloud radars are able to detect ultragiant volcanic aerosols also at a large distance from the source. In this study, an innovative methodology for the observation of giant aerosols using the millimeter wavelength radar has been developed and applied to 6 years of measurements carried out at CNR-IMAA Atmospheric Observatory (CIAO), in Potenza, South Italy, finding more than 40 giant aerosol events per year and a good agreement with the aerosol climatologic data. Besides, the effects of giant aerosols in the local and regional meteorology have been studied by correlating several atmospheric variables in the time period following the observation of giant particles. The meteorological situation has been assessed through the data classification into cases characterized by different pressure vertical velocities at the upper atmosphere (400 hPa), Giant aerosols are correlated to lower values of the Cloud Optical Depth (COD) in presence of stable or unstable atmospheric conditions while higher values are found for an intermediate stability. The giant aerosols effects on the Liquid Water Path (LWP) are closely linked to those in the Aerosol Optical Thickness (AOD). The highest increases in the LWP occurs


    Prashanth Kumar


    Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.

  5. A Giant Urethral Calculus.

    Sigdel, G; Agarwal, A; Keshaw, B W


    Urethral calculi are rare forms of urolithiasis. Majority of the calculi are migratory from urinary bladder or upper urinary tract. Primary urethral calculi usually occur in presence of urethral stricture or diverticulum. In this article we report a case of a giant posterior urethral calculus measuring 7x3x2 cm in a 47 years old male. Patient presented with acute retention of urine which was preceded by burning micturition and dribbling of urine for one week. The calculus was pushed in to the bladder through the cystoscope and was removed by suprapubic cystolithotomy.

  6. Giant infantile pulmonary hemangioma

    Pandya, Rajul; Tummala, Venkat [Hurley Medical Center One Hurley Plaza, Department of Radiology, Flint, MI (United States)


    We present a very unusual case of giant infantile pulmonary hemangioma presenting as a large solitary pulmonary mass. This was successfully managed with surgical resection. Histological examination revealed that the mass was positive for GLUT-1 receptor, a marker for infantile hemangioma. To our knowledge only a few cases of pulmonary hemangioma have been described previously in the literature. Pulmonary hemangiomas are very rare lesions, most of them presenting as a pulmonary mass. This case emphasizes the fact that this rare lesion should be considered in the differential of an enhancing pulmonary mass in an infant. (orig.)

  7. Giant Pandas and Their Conservation



    IT is paradoxical that themost well-known conservation symbol in the world,the giant panda, is a criti-cally endangered species.The estimated 1,600 thatremain live in the high-altitude for-ests of southwest China (within theprovinces of Sichuan, Gansu andShaanxi). Giant pandas are popularand elicit affection and admiration

  8. Famine Threatens the Giant Panda


    Large swathes of arrow bamboo groves at and above 2,700 meters in the Piankou Nature Reserve in Sichuan's Mianyang are producing purple blooms, and some groves have started to wither and die. An absence of bamboo means famine for giant pandas living there. Sichuan has consequently activated its giant panda contingency plan.

  9. From forced collapse to H ii region expansion in Mon R2: Envelope density structure and age determination with Herschel

    Didelon, P; Tremblin, P; Hill, T; Hony, S; Hennemann, M; Hennebelle, P; Anderson, L D; Galliano, F; Schneider, N; Rayner, T; Rygl, K; Louvet, F; Zavagno, A; Konyves, V; Sauvage, M; Andre, Ph; Bontemps, S; Peretto, N; Griffin, M; Gonzalez, M; Lebouteiller, V; Arzoumanian, D; Benedettini, M; Di Francesco, J; Menshchikov, A; Minier, V; Luong, Q Nguyen; Bernard, J -P; Palmeirim, P; Pezzuto, S; Rivera-Ingraham, A; Russeil, D; Ward-Thompson, D; White, G J


    The surroundings of HII regions can have a profound influence on their development, morphology, and evolution. This paper explores the effect of the environment on H II regions in the MonR2 molecular cloud. We aim to investigate the density structure of envelopes surrounding HII regions and to determine their collapse and ionisation expansion ages. The Mon R2 molecular cloud is an ideal target since it hosts an H II region association. Column density and temperature images derived from Herschel data were used together to model the structure of HII bubbles and their surrounding envelopes. The resulting observational constraints were used to follow the development of the Mon R2 ionised regions with analytical calculations and numerical simulations. The four hot bubbles associated with H II regions are surrounded by dense, cold, and neutral gas envelopes. The radial density profiles are reminiscent of those of low-mass protostellar envelopes. The inner parts of envelopes of all four HII regions could be free-fal...

  10. Rapidly Evolving Giant Dermatofibroma

    K. J. Lang


    Full Text Available Dermatofibroma, also known as “fibrous histiocytoma”, is a benign dermal or subcutaneous poorly circumscribed proliferation of spindle-shaped fibroblasts and macrophages in the dermis. Although it is commonly present as a brownish nodule the legs of females, it may also arise on the upper extremities, trunk, and rarely on the head. The exact pathogenesis is unclear. However, it is widely believed that the originating insult to the dermis is a folliculitis, an arthropod bite, or an unspecified initial inflammatory condition. Giant dermatofibromas of greater than 5 cm in diameter are rare, with only 22 cases reported in the literature. We present a case of a rapidly evolving pedunculated mass in the groin of a male patient. Histological examination confirmed this to be a giant dermatofibroma. Though this specimen cannot is not confirmed as such, the cellular subtype is sometimes present as a larger lesion with anecdotal reports of local recurrence and distant metastases. The clinical and radiological features which were somewhat suspicious of malignancy are considered in the context of the definitive pathological diagnosis of a benign lesion.

  11. Giant Cell Fibroma in Children: Report of Two Cases and Literature Review

    Nikolaos G. Nikitakis


    Full Text Available Background: Giant cell fibroma is a type of fibrous tumour of the oral mucosa which rarely affects children under the age of 10. The purpose of this paper was to contribute two clinically and histologically documented cases of giant cell fibroma in the free gingiva of a 7 and 6 year old boys. Methods: Both nodules were presented in the mandibular anterior region. In the differential diagnosis several fibrous hyperplastic lesions were considered such as traumatic fibroma, papilloma, peripheral ossifying fibroma, peripheral odontogenic fibroma, giant cell fibroma and odontogenic hamartoma. Results: The lesions were removed and the histological examination revealed fibrocollagenous connective tissue with the presence of stellate giant cells which confirmed the diagnosis of giant cell fibroma. Conclusions: Dentists should be aware of the existence of giant cell fibroma in children, which must be included in the differential diagnosis of nodular lesions of the gingiva and adequately diagnosed and treated by removal and histopathological examination.

  12. Reinflating Giant Planets

    Kohler, Susanna


    Two new, large gas-giant exoplanets have been discovered orbiting close to their host stars. A recent study examining these planets and others like them may help us to better understand what happens to close-in hot Jupiters as their host stars reach the end of their main-sequence lives.OversizedGiantsUnbinned transit light curves for HAT-P-65b. [Adapted from Hartman et al. 2016]The discovery of HAT-P-65b and HAT-P-66b, two new transiting hot Jupiters, is intriguing. These planets have periods of just under 3 days and masses of roughly 0.5 and 0.8 times that of Jupiter, but their sizes are whats really interesting: they have inflated radii of 1.89 and 1.59 times that of Jupiter.These two planets, discovered using the Hungarian-made Automated Telescope Network (HATNet) in Arizona and Hawaii, mark the latest in an ever-growing sample of gas-giant exoplanets with radii larger than expected based on theoretical planetary structure models.What causes this discrepancy? Did the planets just fail to contract to the expected size when they were initially formed, or were they reinflated later in their lifetimes? If the latter, how? These are questions that scientists are only now starting to be able to address using statistics of the sample of close-in, transiting planets.Unbinned transit light curves for HAT-P-66b. [Hartman et al. 2016]Exploring Other PlanetsLed by Joel Hartman (Princeton University), the team that discovered HAT-P-65b and HAT-P-66b has examined these planets observed parameters and those of dozens of other known close-in, transiting exoplanets discovered with a variety of transiting exoplanet missions: HAT, WASP, Kepler, TrES, and KELT. Hartman and collaborators used this sample to draw conclusions about what causes some of these planets to have such large radii.The team found that there is a statistically significant correlation between the radii of close-in giant planets and the fractional ages of their host stars (i.e., the stars age divided by its full

  13. Giant vortices in the Ginzburg-Landau model

    Sørensen, Mads Peter

    The time-dependent Ginzburg-Landau equation is solved in a region of two spatial dimensions and with complex geometry using the finite element method. The geometry has a marked influence on the vortex distribution and we have observed generation of giant vortices at boundary defects.......The time-dependent Ginzburg-Landau equation is solved in a region of two spatial dimensions and with complex geometry using the finite element method. The geometry has a marked influence on the vortex distribution and we have observed generation of giant vortices at boundary defects....

  14. [EUS results of malignant rectal giant condyloma acuminatum (Buschke-Loewenstein tumor)].

    Strock, Paul; Barrioz, Thierry; Lauroy, Johny; Babin, Philippe; Mordi, Abdel; Fort, Eric; Laurin, Christine; Sevestre, Christian; Silvain, Christine


    Giant condyloma acuminatum is a large, exophytic, cauliflower-like lesion that usually affects the anogenital region. Localisation in the rectum is uncommon and has a high rate of malignant transformation but does not lead to develop distant metastases. For the time, we report the endosonographic appearance of a malignant intrarectal giant condyloma acuminatum.

  15. VizieR Online Data Catalog: HII regions and GMC in the Antennae (Zaragoza-Cardiel+, 2014)

    Zaragoza-Cardiel, J.; Font, J.; Beckman, J. E.; Garcia-Lorenzo, B.; Erroz-Ferrer, S.; Gutierrez, L.


    We present two sets of observations of the Antennae: data cubes of emission in Hα from the ionized component of the interstellar medium and of emission in the CO(3-2) line from the molecular component. (4 data files).

  16. The ionizing radiation from massive stars and its impact on HII regions: results from modern model atmospheres

    Simón-Díaz, S


    We present a detailed comparison of the ionizing spectral energy distributions (SEDs) predicted by four modern stellar atmosphere codes, TLUSTY, CMFGEN, WMbasic, and FASTWIND. We consider three sets of stellar parameters representing a late O-type dwarf (O9.5 V), a mid O-type (O7 V) dwarf, and an early O-type dwarf (O5.5 V). We explore two different possibilities for such a comparison, following what we called evolutionary and observational approaches: in the evolutionary approach one compares the SEDs of stars defined by the same values of Teff and logg; in the observational approach the models to be compared do not necessarily have the same Teff and logg, but produce similar H and HeI-II optical lines. We find that there is a better agreement, in terms of Q(H0), the ratio Q(He0)/Q(H0), and the shape of the SEDs predicted by the four codes in the spectral range between 13 and 30 eV, when models are compared following the observational approach. However, even in this case, large differences are found at highe...

  17. A search for precursors of Ultracompact HII Regions in a sample of luminous IRAS sources; 3, Circumstellar Dust Properties

    Molinari, S; Cesaroni, R; Palla, Fabrizio; Molinari, Sergio; Brand, Jan; Cesaroni, Riccardo; Palla, Francesco


    The James Clerk Maxwell Telescope has been used to obtain submillimeter and millimeter continuum photometry of a sample of 30 IRAS sources previously studied in molecular lines and centimeter radio continuum. All the sources have IRAS colours typical of very young stellar objects (YSOs) and are associated with dense gas. In spite of their high luminosities (L>10000 solar units), only ten of these sources are also associated with a radio counterpart. In 17 cases we could identify a clear peak of millimeter emission associated with the IRAS source, while in 9 sources the millimeter emission was extended or faint and a clear peak could not be identified; upper limits were found in 4 cases only. Using simple greybody fitting model to the observed SED, we derive global properties of the circumstellar dust. The dust temperature varies from 24 K to 45 K, while the exponent of the dust emissivity vs frequency power-law spans a range 1.56

  18. Melting the core of giant planets: impact on tidal dissipation

    Mathis, S


    Giant planets are believed to host central dense rocky/icy cores that are key actors in the core-accretion scenario for their formation. In the same time, some of their components are unstable in the temperature and pressure regimes of central regions of giant planets and only ab-initio EOS computations can address the question of the state of matter. In this framework, several works demonstrated that erosion and redistribution of core materials in the envelope must be taken into account. These complex mechanisms thus may deeply modify giant planet interiors for which signatures of strong tidal dissipation have been obtained for Jupiter and Saturn. The best candidates to explain this dissipation are the viscoelastic dissipation in the central dense core and turbulent friction acting on tidal inertial waves in their fluid convective envelope. In this work, we study the consequences of the possible melting of central regions for the efficiency of each of these mechanisms.

  19. Pygmies, Giants, and Skins

    Piekarewicz, J


    Understanding the equation of state (EOS) of neutron-rich matter is a central goal of nuclear physics that cuts across a variety of disciplines. Indeed, the limits of nuclear existence, the collision of energetic heavy ions, the structure of neutron stars, and the dynamics of core-collapse supernova all depend critically on the nuclear-matter EOS. In this contribution I focus on the EOS of cold baryonic matter with special emphasis on its impact on the structure, dynamics, and composition of neutron stars. In particular, I discuss how laboratory experiments on neutron skins as well as on Pygmy and Giant resonances can help us elucidate the structure of these fascinating objects.

  20. [Giant esophageal fibrovascular polyp].

    Palacios, Fernando; Contardo, Carlos; Guevara, Jorge; Vera, Augusto; Aguilar, Luis; Huamán, Manuel; Palomino, Américo; Yabar, Alejandro


    Fibrovascular polyps are extremely rare benign neoplasias of the esophagus, which usually originate in the lower cricoid area. They do not produce any discomfort in the patient for a long time, however it may make itself evident by the patient's regurgitation of the polyp, producing asphyxia or, more frequently, dysphagia. The case of a 58 year old male patient is presented herein, with a 9 month record of dysphagia, weight loss and intermittent melena. The barium x-ray showed a distended esophagus, with a tumor running from the upper esophageal sphincter to the cardia. The endoscopy confirmed the presence of a pediculated tumor, implanted in the cervical esophagus. Surgeons suspected the potential malignancy of the tumor and performed a transhiatal esophagectomy. The final pathologic diagnosis was giant fibrovascular esophageal polyp.

  1. A giant Ordovician anomalocaridid.

    Van Roy, Peter; Briggs, Derek E G


    Anomalocaridids, giant lightly sclerotized invertebrate predators, occur in a number of exceptionally preserved early and middle Cambrian (542-501 million years ago) biotas and have come to symbolize the unfamiliar morphologies displayed by stem organisms in faunas of the Burgess Shale type. They are characterized by a pair of anterior, segmented appendages, a circlet of plates around the mouth, and an elongate segmented trunk lacking true tergites with a pair of flexible lateral lobes per segment. Disarticulated body parts, such as the anterior appendages and oral circlet, had been assigned to a range of taxonomic groups--but the discovery of complete specimens from the middle Cambrian Burgess Shale showed that these disparate elements all belong to a single kind of animal. Phylogenetic analyses support a position of anomalocaridids in the arthropod stem, as a sister group to the euarthropods. The anomalocaridids were the largest animals in Cambrian communities. The youngest unequivocal examples occur in the middle Cambrian Marjum Formation of Utah but an arthropod retaining some anomalocaridid characteristics is present in the Devonian of Germany. Here we report the post-Cambrian occurrence of anomalocaridids, from the Early Ordovician (488-472 million years ago) Fezouata Biota in southeastern Morocco, including specimens larger than any in Cambrian biotas. These giant animals were an important element of some marine communities for about 30 million years longer than previously realized. The Moroccan specimens confirm the presence of a dorsal array of flexible blades attached to a transverse rachis on the trunk segments; these blades probably functioned as gills.

  2. The Giant Magnetocaloric Effect

    Pecharsky, Vitalij K.


    Since the discovery of the magnetocaloric effect in pure iron by E.Warburg in 1881, it has been measured experimentally on many magnetic metals and compounds. The majority of the materials studied order magnetically undergoing a second order phase transformation. The magnetocaloric effect, typically peaking near the Curie or the Néel temperature, generally ranges from 0.5 to 2 K (in terms of adiabatic temperature change) or at 1 to 4 J/kg K (in terms of isothermal magnetic entropy change) per 1 T magnetic field change. The giant magnetocaloric effect recently discovered in Gd_5(Si_xGe_1-x)4 alloys, where x refrigerant capacity, which is the measure of how much heat can be transferred from a cold to a hot reservoir in one ideal thermodynamic cycle, is larger than that of the best second order phase transition materials by 25 to 100%. When the Gd_5(Si_xGe_1-x)4 alloys are compared with other known materials, which show first order magnetic phase transition, such as Dy, Ho, Er, HoCo_2, NdMn_2Si_2, Fe_0.49Rh_0.51, and (Hf_0.83Ta_0.17)Fe_2+x, only Fe_0.49Rh_0.51 has comparable magnetocaloric properties. However, the first order magnetic phase transition in Fe_0.49Rh_0.51 is irreversible, and the magnetocaloric effect disappears after one magnetizing/demagnetizing cycle. A study of the crystal structure, thermodynamics, and magnetism of the Gd_5(Si_xGe_1-x)4 alloys, where 0 basic relations between the composition, the crystal structure, and the change in thermodynamics and magnetocaloric properties, which occur in the Gd_5(Si_xGe_1-x)4 system, and which brings about the giant magnetocaloric effect when x <= 0.5.

  3. Peripheral giant cell granuloma: A review of 123 cases

    Niloofar Shadman


    Full Text Available Background: Peripheral giant cell granuloma is one of the reactive hyperplastic lesions of the oral cavity, which originates from the periosteum or periodontal membrane following local irritation or chronic trauma. The purpose of this study was to present the clinical characteristics of peripheral gi-ant cell granuloma in a group of Iranian population. Methods: A series of 123 consecutive confirmed cases of peripheral giant cell granuloma after biopsy were evaluated. Age, sex, anatomic location, consistency, etiologic factor, pain and bleeding history, color, surface texture, and pedicle situation were recorded and were analyzed by chi-square test and values were considered to be significant if P < 0.05. Results: Age ranged from 6 to 75 years (mean 33 years. Women affected more than men (M/F 1:1.1. Peripheral giant cell granuloma was seen in the mandible more than in the maxilla and in the anterior region more than in the posterior region. In most cases, lesions were pink, pedunculated and had non-ulcerated surface. In less than half of the cases, there was no history of bleeding and also pain was rarely reported. Calculus was the most common etiologic factor. Conclusion: The results confirmed that the clinical features of peripheral giant cell granuloma in a group of Iranian population are almost similar to those reported by other investigators.

  4. Giant magnetoresistance in bilayer graphene nanoflakes

    Farghadan, Rouhollah; Farekiyan, Marzieh


    Coherent spin transport through bilayer graphene (BLG) nanoflakes sandwiched between two electrodes made of single-layer zigzag graphene nanoribbon was investigated by means of Landauer-Buttiker formalism. Application of a magnetic field only on BLG structure as a channel produces a perfect spin polarization in a large energy region. Moreover, the conductance could be strongly modulated by magnetization of the zigzag edge of AB-stacked BLG, and the junction, entirely made of carbon, produces a giant magnetoresistance (GMR) up to 100%. Intestinally, GMR and spin polarization could be tuned by varying BLG width and length. Generally, MR in a AB-stacked BLG strongly increases (decreases) with length (width).

  5. Asymptomatic Giant Intraventricular Cysticercosis: A Case Report

    Wongjittraporn, Suwarat; Tongma, Chawat; Chung, Heath


    Neurocysticercosis is a growing health problem in the United States and worldwide. Diagnosis and treatment is challenging especially if the physician is not familiar with this condition. The World Health Organization (WHO) estimates that neurocysticercosis affects 50 million people worldwide, especially in developing countries and causes approximately 50,000 deaths annually.1 Neurocysticercosis is of emerging importance in the United States especially in Hawai‘i because of immigration from disease-endemic regions.2 We present a case of a young Chinese immigrant male who presented with impressive imaging studies of a giant intraventricular neurocysticercosis. This case emphasizes the importance of recognizing neurocysticercosis, especially in the immigrant population. PMID:27437162

  6. Landscape of the lost giants


    The Pleistocene megafauna extinction erased a group of remarkable animals. Whether humans had a prominent role in the extinction remains controversial, but it is emerging that the disappearance of the giants has markedly affected the environment.

  7. Atmospheres of Extrasolar Giant Planets

    Marley, M S; Seager, S; Barman, T; Marley, Mark S.; Fortney, Jonathan; Seager, Sara; Barman, Travis


    The key to understanding an extrasolar giant planet's spectrum--and hence its detectability and evolution--lies with its atmosphere. Now that direct observations of thermal emission from extrasolar giant planets are in hand, atmosphere models can be used to constrain atmospheric composition, thermal structure, and ultimately the formation and evolution of detected planets. We review the important physical processes that influence the atmospheric structure and evolution of extrasolar giant planets and consider what has already been learned from the first generation of observations and modeling. We pay particular attention to the roles of cloud structure, metallicity, and atmospheric chemistry in affecting detectable properties through Spitzer Space Telescope observations of the transiting giant planets. Our review stresses the uncertainties that ultimately limit our ability to interpret EGP observations. Finally we will conclude with a look to the future as characterization of multiple individual planets in a ...

  8. Atmospheres of Extrasolar Giant Planets

    Marley, Mark


    The next decade will almost certainly see the direct imaging of extrasolar giant planets around nearby stars. Unlike purely radial velocity detections, direct imaging will open the door to characterizing the atmosphere and interiors of extrasola planets and ultimately provide clues on their formation and evolution through time. This process has already begun for the transiting planets, placing new constraints on their atmospheric structure, composition, and evolution. Indeed the key to understanding giant planet detectability, interpreting spectra, and constraining effective temperature and hence evolution-is the atmosphere. I will review the universe of extrasolar giant planet models, focusing on what we have already learned from modeling and what we will likely be able to learn from the first generation of direct detection data. In addition to these theoretical considerations, I will review the observations and interpretation of the - transiting hot Jupiters. These objects provide a test of our ability to model exotic atmospheres and challenge our current understanding of giant planet evolution.

  9. Annular Elastolytic Giant Cell Granuloma

    Khandpur Sujay


    Full Text Available The clinical and histopathological features of annular elastolytic giant cell granuloma in a 42â€"year-old female patient are described. The condition presented as annular erythematous plaques over sun- exposed skin sparing the face. Histopathology revealed dense granulomatous infiltrate consisting of numerous giant cells and lymphohistiocytes without any palisading arrangement or necrobiosis. The features differentiating it from other similar granulomatous disorders are discussed.

  10. Liquid Water Oceans in Ice Giants

    Wiktorowicz, Sloane J.; Ingersoll, Andrew P.


    Aptly named, ice giants such as Uranus and Neptune contain significant amounts of water. While this water cannot be present near the cloud tops, it must be abundant in the deep interior. We investigate the likelihood of a liquid water ocean existing in the hydrogen-rich region between the cloud tops and deep interior. Starting from an assumed temperature at a given upper tropospheric pressure (the photosphere), we follow a moist adiabat downward. The mixing ratio of water to hydrogen in the gas phase is small in the photosphere and increases with depth. The mixing ratio in the condensed phase is near unity in the photosphere and decreases with depth; this gives two possible outcomes. If at some pressure level the mixing ratio of water in the gas phase is equal to that in the deep interior, then that level is the cloud base. The gas below the cloud base has constant mixing ratio. Alternately, if the mixing ratio of water in the condensed phase reaches that in the deep interior, then the surface of a liquid ocean will occur. Below this ocean surface, the mixing ratio of water will be constant. A cloud base occurs when the photospheric temperature is high. For a family of ice giants with different photospheric temperatures, the cooler ice giants will have warmer cloud bases. For an ice giant with a cool enough photospheric temperature, the cloud base will exist at the critical temperature. For still cooler ice giants, ocean surfaces will result. A high mixing ratio of water in the deep interior favors a liquid ocean. We find that Neptune is both too warm (photospheric temperature too high) and too dry (mixing ratio of water in the deep interior too low) for liquid oceans to exist at present. To have a liquid ocean, Neptune s deep interior water to gas ratio would have to be higher than current models allow, and the density at 19 kbar would have to be approx. equal to 0.8 g/cu cm. Such a high density is inconsistent with gravitational data obtained during the Voyager

  11. Bringing Low the Giants


    Their work goes on unseen, because they a hundred metres beneath your feet. But while the race against the clock to build the LHC has begun on the surface, teams underground are feverishly engaged to dismantle LEP and its experiments. Four months after the start of dismantling, the technical coordinators of the different experiments discuss the progress of work. Little men attack the giant ALEPH. The barrel and its two endcaps have been removed to the end of the cavern and stripped of their cables. The breaking up of the detector can now begin. At ALEPH, counting rooms removed all in one go Jean-Paul Fabre, technical coordinator at ALEPH:'After making safe the structure, the first step was to remove the wiring and cables. Some 210 cubic metres were brought out. Then the counting rooms all round the detector were taken out. They were brought up from the cavern all in one go, up through the shaft, which is 10 metres wide and 150 metres deep. They made it with 15 centimetres to spare. They have been emptied of...

  12. Giant high occipital encephalocele

    Agrawal Amit


    Full Text Available Encephaloceles are rare embryological mesenchymal developmental anomalies resulting from inappropriate ossification in skull through with herniation of intracranial contents of the sac. Encephaloceles are classified based on location of the osseous defect and contents of sac. Convexity encephalocele with osseous defect in occipital bone is called occipital encephalocele. Giant occipital encephaloceles can be sometimes larger than the size of baby skull itself and they pose a great surgical challenge. Occipital encephaloceles (OE are further classified as high OE when defect is only in occipital bone above the foramen magnum, low OE when involving occipital bone and foramen magnum and occipito-cervical when there involvement of occipital bone, foramen magnum and posterior upper neural arches. Chiari III malformation can be associated with high or low occipital encephaloceles. Pre-operatively, it is essential to know the size of the sac, contents of the sac, relation to the adjacent structures, presence or absence of venous sinuses/vascular structures and osseous defect size. Sometimes it becomes imperative to perform both CT and MRI for the necessary information. Volume rendered CT images can depict the relation of osseous defect to foramen magnum and provide information about upper neural arches which is necessary in classifying these lesions.

  13. Giant cell arteritis.

    Ninan, Jem; Lester, Susan; Hill, Catherine


    Giant cell arteritis (GCA) is the most common vasculitis of the elderly. The diagnosis can be challenging at times because of the limitation of the American Rheumatology Association (ARA) classification criteria and the significant proportion of biopsy-negative patients with GCA. We discuss the role of advanced imaging techniques, including positron emission tomography (PET) scanning, in establishing diagnosis and improved histopathology techniques to improve the sensitivity of temporal artery biopsy. There have been significant advances in the understanding of the pathogenesis of GCA, particularly the role of cytokine pathways such as the interleukins, IL-6-IL-17 axis, and the IL-12-interferon-γ axis and their implication for new therapies. We highlight that glucocorticoids remain the primary treatment for GCA, but recognize the risk of steroid-induced side effects. A number of pharmacotherapies to enable glucocorticoid dose reduction and prevent relapse have been studied. Early diagnosis and fast-track pathways have improved outcomes by encouraging adherence to evidence-based practice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Rotation of Giant Stars

    Kissin, Yevgeni


    The internal rotation of post-main sequence stars is investigated, in response to the convective pumping of angular momentum toward the stellar core, combined with a tight magnetic coupling between core and envelope. The spin evolution is calculated using model stars of initial mass 1, 1.5 and $5\\,M_\\odot$, taking into account mass loss on the giant branches and the partitioning of angular momentum between the outer and inner envelope. We also include the deposition of orbital angular momentum from a sub-stellar companion, as influenced by tidal drag as well as the excitation of orbital eccentricity by a fluctuating gravitational quadrupole moment. A range of angular velocity profiles $\\Omega(r)$ is considered in the deep convective envelope, ranging from solid rotation to constant specific angular momentum. We focus on the backreaction of the Coriolis force on the inward pumping of angular momentum, and the threshold for dynamo action in the inner envelope. Quantitative agreement with measurements of core ro...

  15. Imaging Extrasolar Giant Planets

    Bowler, Brendan P


    High-contrast adaptive optics imaging is a powerful technique to probe the architectures of planetary systems from the outside-in and survey the atmospheres of self-luminous giant planets. Direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high-order adaptive optics systems, dedicated planet-finding instruments with specialized coronagraphs, and innovative observing and post-processing strategies to suppress speckle noise. This review summarizes recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments. I conclude with a statistical meta-analysis of deep imaging surveys in the literature. Based on observations of 384 unique and single young ($\\approx$5--300~Myr) stars spanning stellar masses between 0.1--3.0~\\Msun, the overall occurrence rate of 5--13~\\Mjup \\ companions at orbital distances ...

  16. Spectral discrimination of giant reed (Arundo donax L.): A seasonal study in riparian areas

    Fernandes, Maria Rosário; Aguiar, Francisca C.; Silva, João M. N.; Ferreira, Maria Teresa; Pereira, José M. C.


    The giant reed (Arundo donax L.) is amongst the one hundred worst invasive alien species of the world, and it is responsible for biodiversity loss and failure of ecosystem functions in riparian habitats. In this work, field spectroradiometry was used to assess the spectral separability of the giant reed from the adjacent vegetation and from the common reed, a native similar species. The study was conducted at different phenological periods and also for the giant reed stands regenerated after mechanical cutting (giant reed_RAC). A hierarchical procedure using Kruskal-Wallis test followed by Classification and Regression Trees (CART) was used to select the minimum number of optimal bands that discriminate the giant reed from the adjacent vegetation. A new approach was used to identify sets of wavelengths - wavezones - that maximize the spectral separability beyond the minimum number of optimal bands. Jeffries Matusita and Bhattacharya distance were used to evaluate the spectral separability using the minimum optimal bands and in three simulated satellite images, namely Landsat, IKONOS and SPOT. Giant reed was spectrally separable from the adjacent vegetation, both at the vegetative and the senescent period, exception made to the common reed at the vegetative period. The red edge region was repeatedly selected, although the visible region was also important to separate the giant reed from the herbaceous vegetation and the mid infrared region to the discrimination from the woody vegetation. The highest separability was obtained for the giant reed_RAC stands, due to its highly homogeneous, dense and dark-green stands. Results are discussed by relating the phenological, morphological and structural features of the giant reed stands and the adjacent vegetation with their optical traits. Weaknesses and strengths of the giant reed spectral discrimination are highlighted and implications of imagery selection for mapping purposes are argued based on present results.

  17. Guiding the Giant


    New ESO Survey Provides Targets for the VLT Giant astronomical telescopes like the ESO Very Large Telescope (VLT) must be used efficiently. Observing time is expensive and there are long waiting lines of excellent research programmes. Thus the work at the telescope must be very well prepared and optimized as much as possible - mistakes should be avoided and no time lost! Astronomers working with the new 8-m class optical/infrared telescopes must base their observations on detailed lists of suitable target objects if they want to perform cutting-edge science. This is particularly true for research programmes that depend on observations of large samples of comparatively rare, distant objects. This type of work requires that extensive catalogues of such objects must be prepared in advance. One such major catalogue - that will serve as a very useful basis for future VLT observations - has just become available from the new ESO Imaging Survey (EIS). The Need for Sky Surveys Astronomers have since long recognized the need to carry out preparatory observations with other telescopes in order to "guide" large telescopes. To this end, surveys of smaller or larger parts of the sky have been performed by wide-field telescopes, paving the way for subsequent work at the limits of the largest available ground-based telescopes. For instance, a complete photographic survey of the sourthern sky (declination deep imaging surveys have thus become an indispensable complement to the 8-m telescopes. The new generation of imaging surveys will, without doubt, be the backbone of future research and are likely to be as long-lived as their earlier counterparts, which have served the astronomical community so well over the past decades. The new surveys are now becoming possible, thanks to the new, extremely light-sensitive CCD-mosaics mounted on wide-field telescopes. The ESO Imaging Survey (EIS) A very successful, major step in this direction has recently been taken at ESO. It concerns an

  18. Enrichment of nutritional value of Phyllanthus emblica fruit juice using the probiotic bacterium, Lactobacillus paracasei HII01 mediated fermentation

    Sartjin PEERAJAN


    Full Text Available The fermented herbal juices are capable of curing and preventing diseases and reducing the aging progress. The present study was performed to investigate the fermentation of Phyllanthus emblica fruit by Lactobacillus paracasei HII01 with respect to carbon sources, polyphenols, and antioxidant properties. The physical changes, for instance, color, odor, taste, turbidity and gas formation, throughout the fermentation process was manually monitored. The fermented product was rich in polyphenolic content. The acid content and pH of the product were under the norms of Thai community product standards. Antioxidant properties of the fermented product were proved using ABTS, and FRAP assays. Chelation based study suggested that fermented P. emblica fruit juices are healthy enough to stabilize the oxidized form of the metal ion. The optimum fermentation period was 15 days. All the results supported that studied carbon sources did not interfere with the quality of the product. This report is the prelude study on the use of probiotic starter culture for the production of P. emblica fruit based lactic acid bacteria fermented beverages (LAFB enriched with bioactive compounds. Further research on the impact of different carbon sources and upstream processes on the quality of LAFB is currently in progress.

  19. Young stellar population and ongoing star formation in the HII complex Sh2-252

    Jose, Jessy; Samal, M R; Ojha, D K; Ogura, K; Kim, J S; Kobayashi, N; Goyal, A; Chauhan, N; Eswaraiah, C


    In this paper an extensive survey of the star forming complex Sh2-252 has been undertaken with an aim to explore its hidden young stellar population as well as to understand the structure and star formation history. This complex is composed of five embedded clusters associated with the sub-regions A, C, E, NGC 2175s and Teu 136. Using 2MASS-NIR and Spitzer-IRAC, MIPS photometry we identified 577 young stellar objects (YSOs), of which, 163 are Class I, 400 are Class II and 14 are transition disk YSOs. Spatial distribution of the candidate YSOs shows that they are mostly clustered around the sub-regions in the western half of the complex, suggesting enhanced star formation activity towards its west. Using the spectral energy distribution and optical colour-magnitude diagram based age analyses, we derived probable evolutionary status of the sub-regions of Sh2-252. Our analysis shows that the region A is the youngest (~ 0.5 Myr), the regions B, C and E are of similar evolutionary stage (~ 1-2 Myr) and the cluster...

  20. Timing of the formation and migration of giant planets as constrained by CB chondrites

    Johnson, Brandon C.; Walsh, Kevin J.; Minton, David A.; Krot, Alexander N.; Levison, Harold F.


    The presence, formation, and migration of giant planets fundamentally shape planetary systems. However, the timing of the formation and migration of giant planets in our solar system remains largely unconstrained. Simulating planetary accretion, we find that giant planet migration produces a relatively short-lived spike in impact velocities lasting ~0.5 My. These high-impact velocities are required to vaporize a significant fraction of Fe,Ni metal and silicates and produce the CB (Bencubbin-like) metal-rich carbonaceous chondrites, a unique class of meteorites that were created in an impact vapor-melt plume ~5 My after the first solar system solids. This indicates that the region where the CB chondrites formed was dynamically excited at this early time by the direct interference of the giant planets. Furthermore, this suggests that the formation of the giant planet cores was protracted and the solar nebula persisted until ~5 My. PMID:27957541

  1. Timing of the formation and migration of giant planets as constrained by CB chondrites.

    Johnson, Brandon C; Walsh, Kevin J; Minton, David A; Krot, Alexander N; Levison, Harold F


    The presence, formation, and migration of giant planets fundamentally shape planetary systems. However, the timing of the formation and migration of giant planets in our solar system remains largely unconstrained. Simulating planetary accretion, we find that giant planet migration produces a relatively short-lived spike in impact velocities lasting ~0.5 My. These high-impact velocities are required to vaporize a significant fraction of Fe,Ni metal and silicates and produce the CB (Bencubbin-like) metal-rich carbonaceous chondrites, a unique class of meteorites that were created in an impact vapor-melt plume ~5 My after the first solar system solids. This indicates that the region where the CB chondrites formed was dynamically excited at this early time by the direct interference of the giant planets. Furthermore, this suggests that the formation of the giant planet cores was protracted and the solar nebula persisted until ~5 My.

  2. Leonardo Da Vinci’s giant crossbow

    Landrus, Matt


    Leonardo's Giant Crossbow is one of his least understood drawings. This fascinating book offers the first in-depth account of its likely purpose and its highly resolved design. It presents original research and new discoveries about the giant crossbow.

  3. Atmospheres of Extrasolar Giant Planets

    Marley, M. S.; Fortney, J.; Seager, S.; Barman, T.

    The key to understanding an extrasolar giant planet's spectrum - and hence its detectability and evolution - lies with its atmosphere. Now that direct observations of thermal emission from extrasolar giant planets (EGPs) are in hand, atmosphere models can be used to constrain atmospheric composition, thermal structure, and ultimately the formation and evolution of detected planets. We review the important physical processes that influence the atmospheric structure and evolution of EGPs and consider what has already been learned from the first generation of observations and modeling. We pay particular attention to the roles of cloud structure, metallicity, and atmospheric chemistry in affecting detectable properties through Spitzer Space Telescope observations of the transiting giant planets. Our review stresses the uncertainties that ultimately limit our ability to interpret EGP observations. Finally we will conclude with a look to the future as characterization of multiple individual planets in a single stellar system leads to the study of comparative planetary architectures.

  4. Giant lobelias exemplify convergent evolution.

    Givnish, Thomas J


    Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution.

  5. Giant lobelias exemplify convergent evolution

    Givnish Thomas J


    Full Text Available Abstract Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution.

  6. Structure of giant muscle proteins

    Nathan Thompson Wright


    Full Text Available Giant muscle proteins (e.g. titin, nebulin, and obscurin play a seminal role in muscle elasticity, stretch response, and sarcomeric organization. Each giant protein consists of multiple tandem structural domains, usually arranged in a modular fashion ranging from 500 kDa to 4 MDa. Although many of the domains are similar in structure, subtle differences create a unique function of each domain. Recent high and low resolution structural and dynamic studies now suggest more nuanced overall protein structures than previously realized. These findings show that atomic structure, interactions between tandem domains, and intrasarcomeric environment all influence the shape, motion, and therefore function of giant proteins. In this article we will review the current understanding of titin, obscurin, and nebulin structure, from the atomic level through the molecular level.

  7. Probing the Deep End of the Milky Way with New Oscillating Kepler Giants

    Mathur, Savita; Huber, Daniel; Regulo, Clara; Stello, Dennis; Beck, Paul G; Houmani, Kenza; Salabert, David


    The Kepler mission has been a success in both exoplanet search and stellar physics studies. Red giants have actually been quite a highlight in the Kepler scene. The Kepler long and almost continuous four-year observations allowed us to detect oscillations in more than 15,000 red giants targeted by the mission. However by looking at the power spectra of 45,000 stars classified as dwarfs according to the Q1-16 Kepler star properties catalog, we detected red-giant like oscillations in 850 stars. Even though this is a small addition to the known red-giant sample, these misclassified stars represent a goldmine for galactic archeology studies. Indeed they happen to be fainter (down to Kp~16) and more distant (d>10kpc) than the known red giants, opening the possibility to probe unknown regions of our Galaxy. The faintness of these red giants with detected oscillations is very promising for detecting acoustic modes in red giants observed with K2 and TESS. In this talk, I will present this new sample of red giants wit...

  8. Giant intravesical calculus during pregnancy.

    Escobar-del Barco, Laura; Rodriguez-Colorado, Silvia; Dueñas-Garcia, Omar Felipe; Avilez-Cevasco, Juan Carlos


    Urolithiasis is commonly found during pregnancy; but the presence of a giant vesical calculus during pregnancy is a very rare entity, associated with several potential obstetric complications. A 25-year-old primigravida at 25 weeks of gestational age was referred to our tertiary care unit because she presented a giant hyperechoic intravesical mass and inability to pass urine with suprapubic pain since 2 days. An open cystolithotomy revealed a huge intravesical calculus. The patient continued with her pregnancy until full term without adverse perinatal outcomes.

  9. Giant fields in southwest Mexico


    According to Petroleos Mexicanos southeastern Mexico's Isthmus Saline basin holds five new giant fields - Tonala-El Burro, El Plan, Cinco Presidentes, Oraggio, and Magallanes - producing oil and gas from Tertiary sandstones. Numerous normal faults resulting from salt intrusion have given rise to multiple blocks, each with its own reservoir conditions. Previously discovered basins in the area include the Macuspana, which holds three giant gas- and condensate-producing fields: Jose Colomo, Chilapilla, and Hormiquero. The 3100-mi/sup 2/ Campeche marine platform, extending offshore nearby, contains the Cantarell complex, Mexico's most productive hydrocarbon province.

  10. Management of a giant perineal condylomata acuminata

    Hemper, Evelyn


    Full Text Available A condylomata acuminata infection is caused by human papillomaviridae (HPV. This sexually transmitted condition most often affects the perineal region. Importantly, infections with types 16 and 18 are associated with an increased risk for anal and cervix cancer. In most cases topical therapy is sufficient for successfully treating condylomata acuminata. Here, we report the case of a 51-year old patient who suffered from a giant perianal located condylomata acuminata which had developed over a period of more than 10 years. Imaging by MRI revealed a possible infiltration of the musculus sphincter ani externus. Because a topical treatment or a radiotherapy was considered unfeasible, a surgical treatment was the only therapeutic option in this unusual case. First, a colostomy was performed and subsequently a resection of the tumor with circular resection of the external portion of the musculus sphincter ani externus was performed. The large skin defect was closed by two gluteus flaps. The rectum wall was reinserted in the remnant of the musculus sphincter ani externus. Postoperatively, parts of the flaps developed necrosis. Therefore, a vacuum sealing therapy was initiated. Subsequently, the remaining skin defects were closed by autologous skin transplantation. Six months later the colostomy could be reversed. To date, one year after first surgery, the patient has still a normal sphincter function and no recurrence of the condylomata acuminata. This case report demonstrates how giant condylomata acuminata can be successfully treated by extended surgical procedures including colostomy and plastic reconstruction of resulting defects upon resection.

  11. Impacts of temperature on giant panda habitat in the north Minshan Mountains.

    Liu, Gang; Guan, Tianpei; Dai, Qiang; Li, Huixin; Gong, Minghao


    Understanding the impacts of meteorological factors on giant pandas is necessary for future conservation measures in response to global climate change. We integrated temperature data with three main habitat parameters (elevation, vegetation type, and bamboo species) to evaluate the influence of climate change on giant panda habitat in the northern Minshan Mountains using a habitat assessment model. Our study shows that temperature (relative importance = 25.1%) was the second most important variable influencing giant panda habitat excepting the elevation. There was a significant negative correlation between temperature and panda presence (ρ = -0.133, P pandas within the study area was 18-21°C, followed by 15-17°C and 22-24°C. The overall suitability of giant panda habitats will increase by 2.7%, however, it showed a opposite variation patterns between the eastern and northwestern region of the study area. Suitable and subsuitable habitats in the northwestern region of the study area, which is characterized by higher elevation and latitude, will increase by 18007.8 hm(2) (9.8% habitat suitability), while the eastern region will suffer a decrease of 9543.5 hm(2) (7.1% habitat suitability). Our results suggest that increasing areas of suitable giant panda habitat will support future giant panda expansion, and food shortage and insufficient living space will not arise as problems in the northwest Minshan Mountains, which means that giant pandas can adapt to climate change, and therefore may be resilient to climate change. Thus, for the safety and survival of giant pandas in the Baishuijiang Reserve, we propose strengthening the giant panda monitoring program in the west and improving the integrity of habitats to promote population dispersal with adjacent populations in the east.

  12. HII and H2 in the envelopes of cooling flow central galaxies

    Jaffe, W; Baker, K


    We report observations of ionized and warm molecular gas in the extended regions of the central galaxies in several cooling flow clusters. These show that both gas phases are present in these clusters to large radii. We trace both Pa alpha and H2 lines to radii in excess of 20 kpc. The surface brightness profiles of the two phases trace each other closely. Apart from very close to the central AGN, line ratios in and between the phases vary only slowly with position. The kinematics of the phases are indistinguishable and away from the influence of the central AGN both the mean and dispersion in velocity are low (= 10^5 K.

  13. Giant lipomas of the hand

    Gokce Yildiran


    Conclusion: Giant lipomas of the hand are very rare and may cause compressions and other complications. Thus, they require a careful preoperative evaluation in order to make a proper differential diagnosis. [Hand Microsurg 2015; 4(1.000: 8-11

  14. A Giant or a Dwarf?

    Schmid, Herman


    EU may appear to be a giant when it can act on behalf of a united Europe, but usually it is hampered by conflicting member state interests. The EU economic and administrative resources for foreign and trade policy are quite small (on level with one of its major member states) and the hopes in man...

  15. The giant panda gut microbiome.

    Wei, Fuwen; Wang, Xiao; Wu, Qi


    Giant pandas (Ailuropoda melanoleuca) are bamboo specialists that evolved from carnivores. Their gut microbiota probably aids in the digestion of cellulose and this is considered an example of gut microbiota adaptation to a bamboo diet. However, this issue remains unresolved and further functional and compositional studies are needed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Michigan has a sleeping giant

    Brock, Raymond; Nichols, Sue


    "That giant is 750 miles of fiber optic cable that lassoes its three biggest research universities and Van Andel Institute to the future. Its mission: to uncover the nature of the Big Bang by connecton U.S. physicists to their huge experiment ATLAS in Geneva.." (4 pages)

  17. Multiphonon giant resonances in nuclei

    Aumann, T. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Bortignon, P.F. [Milan Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Milan (Italy); Emling, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)


    We review the present knowledge of multiphonon giant resonances in nuclei. Theoretical concepts approaching the intrinsic structure and excitation mechanisms of multi-phonon states are discussed. The available experimental results are summarized, including a brief description of applied techniques. This review emphasizes electromagnetic excitations of double dipole resonances. Open questions and possible routes toward a solution are addressed. (orig.)

  18. A Giant or a Dwarf?

    Schmid, Herman


    EU may appear to be a giant when it can act on behalf of a united Europe, but usually it is hampered by conflicting member state interests. The EU economic and administrative resources for foreign and trade policy are quite small (on level with one of its major member states) and the hopes in man...

  19. Cloud formation in giant planets

    Helling, Christiane


    We calculate the formation of dust clouds in atmospheres of giant gas-planets. The chemical structure and the evolution of the grain size distribution in the dust cloud layer is discussed based on a consistent treatment of seed formation, growth/evaporation and gravitational settling. Future developments are shortly addressed.

  20. A rare case of giant cell fibroma in a pediatric patient

    Sangeeta Rajesh Patankar


    Full Text Available Fibrous hyperplastic lesions are frequently encountered in the oral cavity. Although clinically similar, these lesions show variations histologically. Giant cell fibroma (GCF is one such nonneoplastic fibrous lesion with a characteristic histopathological feature of stellate-shaped multinuclear or mononuclear fibroblasts known as giant cell fibroblasts. In the recent years, more and more GCF cases have been reported in pediatric patients. This case report describes a papillary soft tissue growth in the lower right posterior region of the mandible in a 5-year-old child with a review on giant cell fibroblasts.

  1. Synaptic elements for GABAergic feed-forward signaling between HII horizontal cells and blue cone bipolar cells are enriched beneath primate S-cones.

    Christian Puller

    Full Text Available The functional roles and synaptic features of horizontal cells in the mammalian retina are still controversial. Evidence exists for feedback signaling from horizontal cells to cones and feed-forward signaling from horizontal cells to bipolar cells, but the details of the latter remain elusive. Here, immunohistochemistry and confocal microscopy were used to analyze the expression patterns of the SNARE protein syntaxin-4, the GABA receptor subunits α1 and ρ, and the cation-chloride cotransporters NKCC and KCC2 in the outer plexiform layer of primate retina. In macaque retina, as observed previously in other species, syntaxin-4 was expressed on dendrites and axon terminals of horizontal cells at cone pedicles and rod spherules. At cones, syntaxin-4 appeared densely clustered in two bands, at horizontal cell dendritic tips and at the level of desmosome-like junctions. Interestingly, in the lower band where horizontal cells may synapse directly onto bipolar cells, syntaxin-4 was highly enriched beneath short-wavelength sensitive (S cones and colocalized with calbindin, a marker for HII horizontal cells. The enrichment at S-cones was not observed in either mouse or ground squirrel. Furthermore, high amounts of both GABA receptor and cation-chloride cotransporter subunits were found beneath primate S-cones. Finally, while syntaxin-4 was expressed by both HI and HII horizontal cell types, the intense clustering and colocalization with calbindin at S-cones indicated an enhanced expression in HII cells. Taken together, GABA receptors beneath cone pedicles, chloride transporters, and syntaxin-4 are putative constituents of a synaptic set of proteins which would be required for a GABA-mediated feed-forward pathway via horizontal cells carrying signals directly from cones to bipolar cells.

  2. Looking for outflow and infall signatures in high mass star forming regions

    Klaassen, P D; Beuther, H


    (Context) Many physical parameters change with time in star forming regions. Here we attempt to correlate changes in infall and outflow motions in high mass star forming regions with evolutionary stage using JCMT observations. (Aims) From a sample of 45 high mass star forming regions in three phases of evolution, we investigate the presence of established infall and outflow tracers to determine whether there are any trends attributable to the age of the source. (Methods) We obtained JCMT observations of HCO+/H13CO+ J=4-3 to trace large scale infall, and SiO J=8-7 to trace recent outflow activity. We compare the infall and outflow detections to the evolutionary stage of the host source (high mass protostellar objects, hypercompact HII regions and ultracompact HII regions). We also note that the integrated intensity of SiO varies with the full width at half maximum of the H13CO+. (Results) We find a surprising lack of SiO detections in the middle stage (Hypercompact HII regions), which may be due to an observat...


    Matsumura, Soko [Department of Astronomy and Astrophysics, University of Maryland, College Park, MD 20741 (United States); Ida, Shigeru; Nagasawa, Makiko [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo (Japan)


    The orbital distributions of currently observed extrasolar giant planets allow marginally stable orbits for hypothetical, terrestrial planets. In this paper, we propose that many of these systems may not have additional planets on these ''stable'' orbits, since past dynamical instability among giant planets could have removed them. We numerically investigate the effects of early evolution of multiple giant planets on the orbital stability of the inner, sub-Neptune-like planets which are modeled as test particles, and determine their dynamically unstable region. Previous studies have shown that the majority of such test particles are ejected out of the system as a result of close encounters with giant planets. Here, we show that secular perturbations from giant planets can remove test particles at least down to 10 times smaller than their minimum pericenter distance. Our results indicate that, unless the dynamical instability among giant planets is either absent or quiet like planet-planet collisions, most test particles down to {approx}0.1 AU within the orbits of giant planets at a few AU may be gone. In fact, out of {approx}30% of survived test particles, about three quarters belong to the planet-planet collision cases. We find a good agreement between our numerical results and the secular theory, and present a semi-analytical formula which estimates the dynamically unstable region of the test particles just from the evolution of giant planets. Finally, our numerical results agree well with the observations, and also predict the existence of hot rocky planets in eccentric giant planet systems.

  4. Making "Green Giants"

    Jones, Geoffrey; Lubinski, Christina


    relations strategies not only to contain fallout from criticism, but also as opportunities for changes in corporate culture. The article finds no evidence for variety of capitalism explanations why German firms should have been early in their sustainability strategies, partly because of the importance...... of regional as opposed to national influences, but the study is supportive of organisational sociology theory about the importance of visibility in corporate green strategies....

  5. Giant hepatic hydatid cyst: A case report

    Ali Ezer; Tank Zafer Nursal; Turgut Noyan; G(o)khan Moray


    Large type 1 cysts are prone to perforation. Furthermore, insufficient drainage with subsequent abscess is a frequent problem of large cysts. We report here a case of a 19-year old man who was admitted to the hospital with pain in the right upper quadrant and epigastric region. An asymmetrical right upper quadrant enlargement was detected on physical examination. Ultrasonography and computerized tomography revealed a type 1 giant hydatid cyst in the right hepatic lobe, measuring 16 cm in diameter. During operation, partial cystectomy and drainage were done. The large dead space was obliterated by the 'sandwich' method. Omentum and gelatin sponges were used to fill the cavity. The postoperative period was uneventful and the patient was discharged on the 5th postoperative day.

  6. A Giant Hemangioma of the Tongue

    Babak Saedi


    Full Text Available Introduction: Vascular abnormalities are relatively uncommon lesions, but head and neck is a common region for vascular malformation which is classified as benign tumors. In this paper, the authors report a rare presentation of vascular malformation in the tongue and its managements. Case Report: An 18 months 2 old child presented with a giant mass of tongue which caused functional and aesthetic problem. The rapid growth pattern of cavernous hemangioma was refractory to corticosteroid. The lesion was excised without any complication. Since the mass was so huge that not only filled entire oral cavity but was protruding outside, airway management was a great challenge for anesthesia plan and at the same time surgical technique was difficult to select. Conclusion: Despite different recommended modalities in managing hemangiomas of the tongue, in cases of huge malformations, surgery could be the mainstay treatment and provided that critical care measures are taken in to account, could be performed very safely.

  7. Morphometric image analysis of giant vesicles

    Husen, Peter Rasmussen; Arriaga, Laura; Monroy, Francisco


    We have developed a strategy to determine lengths and orientations of tie lines in the coexistence region of liquid-ordered and liquid-disordered phases of cholesterol containing ternary lipid mixtures. The method combines confocal-fluorescence-microscopy image stacks of giant unilamellar vesicles...... (GUVs), a dedicated 3D-image analysis, and a quantitative analysis based in equilibrium thermodynamic considerations. This approach was tested in GUVs composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine/1,2-palmitoyl-sn-glycero-3-phosphocholine/cholesterol. In general, our results show a reasonable...... agreement with previously reported data obtained by other methods. For example, our computed tie lines were found to be nonhorizontal, indicating a difference in cholesterol content in the coexisting phases. This new, to our knowledge, analytical strategy offers a way to further exploit fluorescence...

  8. Spectroscopic determination of masses (and implied ages) for red giants

    Ness, M; Rix, H-W; Martig, M; Pinsonneault, Marc H; Ho, A Y Q


    The mass of a star is arguably its most fundamental parameter. For red giant stars, tracers luminous enough to be observed across the Galaxy, mass implies a stellar evolution age. It has proven to be extremely difficult to infer ages and masses directly from red giant spectra using existing methods. From the KEPLER and APOGEE surveys, samples of several thousand stars exist with high-quality spectra and asteroseismic masses. Here we show that from these data we can build a data-driven spectral model using The Cannon, which can determine stellar masses to $\\sim$ 0.07 dex from APOGEE DR12 spectra of red giants; these imply age estimates accurate to $\\sim$ 0.2 dex (40 percent). We show that The Cannon constrains these ages foremost from spectral regions with CN absorption lines, elements whose surface abundances reflect mass-dependent dredge-up. We deliver an unprecedented catalog of 80,000 giants (including 20,000 red-clump stars) with mass and age estimates, spanning the entire disk (from the Galactic center t...

  9. Giant calcified meningioma after radiation therapy; A case report

    Zenke, Kiichiro; Fukumoto, Shinya; Ohta, Shinsuke; Sakaki, Saburo (Ehime Univ., Shigenobu (Japan). School of Medicine); Matsui, Seishi


    We presented a case of secondary giant meningioma with dense calcification (brain stone) after radiation therapy for primary ependymoma removed 25 years before. A 31-year-old man was referred to our hospital because of generalized convulsion. He had received extirpation of an ependymoma in the left frontoparietal region and postoperative radiation therapy 25 years before. Skull X-ray and CT revealed a giant brain stone in the left parietal region. It was totally removed en bloc. Photomicrograph of the specimen showed proliferation of arachnoid cell-like tumor cells in narrow spaces surrounded by marked calcified lesions which showed partial ossification. The etiology and therapy of this tumor were discussed. (author).

  10. Giant Primary Mature Retroperitoneal Teratomain in Adult Male Patient

    R. Ebrahimian; D. Tasa


    Introduction: Teratomas are congenital tumors consisting of derivatives from the ectoderm, endoderm and mesoderm germ cell layers. A teratoma is considered to be a non-seminomatous germ cell tumor and is typically located in either the sacrococcygeal region or in the gonads. Giant retroperitoneal teratomas in adults are even rarer, with only a few cases previously described in the literature. Case report: A 35-year-old male patient with severe nausea and vomiting was taken to the emergency wa...

  11. Serological survey on canine coronavirus antibodies in giant pandas by virus neutralization test

    QIAOJun; XIAXian-zhu; YANGSong-tao; LIDe-sheng; HUGui-xue; GAOYu-wei; SUNHe-ting; ZHAOZhong-pen; XlEZhi-jing; YANFang; HEWen-qi; HUANGGen


    In order to survey the infectious situation of canine coronavirus (CCV) in giant panda population, a virus neutralization test detecting specific antibodies against CCV in giant panda's sera was established by using two-fold dilutions of serum and 100 TCID50 of the virus. The 62 sera samples of giant pandas, which were gathered from zoos and reserve region of Sichuan Province, China were detected. The neutralization antibody titer of 1:4 was recognized as the positive criterion, 8 sera samples were detected to be positive, and the positive rate was 12.9%. The titers of neutralizing antibody ranged from 1:8 to 1:32. It was the first comprehensive investigation on neutralization antibodies against CCV in giant panda population in China. The results of study showed that the infection of CCV in giant panda population was universal, which has posed a threat to the health of giant panda. Therefore, it is incumbent on us to study safe and effective vaccines to protect giant panda against CCV infection.

  12. Asteroseismology of Red Giant stars

    Tarrant, N J; Elsworth, Y P; Spreckley, S A; Stevens, I R


    Sun-like oscillations, that is p-modes excited stochastically by convective noise, have now been observed in a number of Red Giant stars. Compared to those seen in the Sun, these modes are of large amplitude and long period, making the oscillations attractive prospects for observation. However, the low Q-factor of these modes, and issues relating to the rising background at low frequencies, present some interesting challenges for identifying modes and determining the related asteroseismic parameters. We report on the analysis procedure adopted for peak-bagging by our group at Birmingham, and the techniques used to robustly ensure these are not a product of noise. I also show results from a number of giants extracted from multi-year observations with the SMEI instrument.

  13. Idiopathic giant right atrial aneurysm

    Uppu, Santosh C; Sachdeva, Ritu; Imamura, Michiaki


    A 2-year-old boy with an incidental finding of massive cardiomegaly on a chest X-ray was diagnosed with a giant right atrial aneurysm upon further investigation with echocardiography. The patient underwent successful surgical reduction of the right atrium and closure of the patent foramen ovale to prevent thromboembolic complications and to lower the risk of atrial arrhythmias. The resected atrium had paper-thin walls and pathological features of interstitial fibrosis with endocardial thickening. PMID:23626440

  14. Idiopathic giant right atrial aneurysm

    Uppu, Santosh C; Ritu Sachdeva; Michiaki Imamura


    A 2-year-old boy with an incidental finding of massive cardiomegaly on a chest X-ray was diagnosed with a giant right atrial aneurysm upon further investigation with echocardiography. The patient underwent successful surgical reduction of the right atrium and closure of the patent foramen ovale to prevent thromboembolic complications and to lower the risk of atrial arrhythmias. The resected atrium had paper-thin walls and pathological features of interstitial fibrosis with endocardial thicken...

  15. Idiopathic giant right atrial aneurysm

    Santosh C Uppu


    Full Text Available A 2-year-old boy with an incidental finding of massive cardiomegaly on a chest X-ray was diagnosed with a giant right atrial aneurysm upon further investigation with echocardiography. The patient underwent successful surgical reduction of the right atrium and closure of the patent foramen ovale to prevent thromboembolic complications and to lower the risk of atrial arrhythmias. The resected atrium had paper-thin walls and pathological features of interstitial fibrosis with endocardial thickening.

  16. Ionization Parameter as a Diagnostic of Radiation and Wind Pressures in H II Regions and Starburst Galaxies

    Yeh, Sherry C C


    The ionization parameter U is potentially useful for measuring radiation pressure feedback from massive star clusters, as it reflects the radiation-to-gas-pressure ratio and is readily derived from mid-infrared line ratios. We consider several effects which determine the apparent value of U in HII regions and galaxies. An upper limit is set by the compression of gas by radiation pressure. The pressure from stellar winds and the presence of neutral clumps both reduce U for a given radiation intensity. The most intensely irradiated regions are selectively dimmed by internal dust absorption of ionizing photons, inducing observational bias on galactic scales. We explore these effects analytically and numerically, and use them to interpret previous observational results. We find that radiation confinement sets the upper limit log_10 U = -1 seen in individual regions. Unresolved starbursts display a maximum value of ~ -2.3. While lower, this is also consistent with a large portion of their HII regions being radiati...

  17. Electrodynamics in Giant Planet Atmospheres

    Koskinen, T.; Yelle, R. V.; Lavvas, P.; Cho, J.


    The atmospheres of close-in extrasolar giant planets such as HD209458b are strongly ionized by the UV flux of their host stars. We show that photoionization on such planets creates a dayside ionosphere that extends from the thermosphere to the 100 mbar level. The resulting peak electron density near the 1 mbar level is higher than that encountered in any planetary ionosphere of the solar system, and the model conductivity is in fact comparable to the atmospheres of Sun-like stars. As a result, the momentum and energy balance in the upper atmosphere of HD209458b and similar planets can be strongly affected by ion drag and resistive heating arising from wind-driven electrodynamics. Despite much weaker ionization, electrodynamics is nevertheless also important on the giant planets of the solar system. We use a generic framework to constrain the conductivity regimes on close-in extrasolar planets, and compare the results with conductivites based on the same approach for Jupiter and Saturn. By using a generalized Ohm's law and assumed magnetic fields, we then demonstrate the basic effects of wind-driven ion drag in giant planet atmospheres. Our results show that ion drag is often significant in the upper atmosphere where it can also substantially alter the energy budget through resistive heating.

  18. Observed Properties of Giant Cells

    Hathaway, David H.; Upton, Lisa; Colegrove, Owen


    The existence of Giant Cells has been suggested by both theory and observation for over 45 years. We have tracked the motions of supergranules in SDO/HMI Doppler velocity data and find larger (Giant Cell) flows that persist for months. The flows in these cells are clockwise around centers of divergence in the north and counter-clockwise in the south. Equatorward flows are correlated with prograde flows - giving the transport of angular momentum toward the equator that is needed to maintain the Sun's rapid equatorial rotation. The cells are most pronounced at mid- and high-latitudes where they exhibit the rotation rates representative of those latitudes. These are clearly large, long-lived, cellular features, with the dynamical characteristics expected from the effects of the Sun's rotation, but the shapes of the cells are not well represented in numerical models. While the Giant Cell flow velocities are small (<10 m/s), their long lifetimes should nonetheless substantially impact the transport of magnetic flux in the Sun's near surface layers.


    Costa, A. D.; Martins, B. L. Canto; Bravo, J. P.; Paz-Chinchón, F.; Chagas, M. L. das; Leão, I. C.; Oliveira, G. Pereira de; Silva, R. Rodrigues da; Roque, S.; Oliveira, L. L. A. de; Silva, D. Freire da; De Medeiros, J. R., E-mail: [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal RN (Brazil)


    Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of substellar companions by their hosting stars. In the present Letter, we report 17 giant stars observed in the scope of the Kepler space mission exhibiting rapid rotation behavior. For the first time, the abnormal rotational behavior for this puzzling family of stars is revealed by direct measurements of rotation, namely from photometric rotation period, exhibiting a very short rotation period with values ranging from 13 to 55 days. This finding points to remarkable surface rotation rates, up to 18 times the rotation of the Sun. These giants are combined with six others recently listed in the literature for mid-infrared (IR) diagnostics based on Wide-field Infrared Survey Explorer information, from which a trend for an IR excess is revealed for at least one-half of the stars, but at a level far lower than the dust excess emission shown by planet-bearing main-sequence stars.

  20. Kepler rapidly rotating giant stars

    Costa, A D; Bravo, J P; Paz-Chinchón, F; Chagas, M L das; Leão, I C; de Oliveira, G Pereira; da Silva, R Rodrigues; Roque, S; de Oliveira, L L A; da Silva, D Freire; De Medeiros, J R


    Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of sub-stellar companions by their hosting stars. In the present letter we report 17 giant stars observed in the scope of the Kepler space mission exhibiting rapid rotation behavior. For the first time the abnormal rotational behavior for this puzzling family of stars is revealed by direct measurements of rotation, namely from photometric rotation period, exhibiting very short rotation period with values ranging from 13 to 55 days. This finding points for remarkable surface rotation rates, up to 18 times the Sun rotation. These giants are combined with 6 other recently listed in the literature for mid-IR diagnostic based on WISE information, from which a trend for an infrared excess is revealed for at least a half of the stars, but at a level far lower than the dust excess emission shown by planet-bearing main-sequence stars.

  1. Rapid Formation of Ice Giant Planets

    Boss, A P; Haghighipour, N; Boss, Alan P.; Wetherill, George W.; Haghighipour, Nader


    The existence of Uranus and Neptune presents severe difficulties for the core accretion model for the formation of ice giant planets. We suggest an alternative mechanism, namely disk instability leading to the formation of gas giant protoplanets, coagulation and settling of dust grains to form ice/rock cores at their centers, and photoevaporation of their gaseous envelopes by a nearby OB star, as a possible means of forming ice giant planets.

  2. Solitary ulcerated congenital giant juvenile xanthogranuloma

    Su Yuen Ng


    Full Text Available A 3-month-old female patient with a giant ulcerated nodule over the back since birth was diagnosed as congenital giant juvenile xanthogranuloma (JXG based on clinical and histopathological examination. Congenital giant JXG with ulceration at birth is a rare presentation of JXG and commonly misdiagnosed. This case emphasizes the importance of being aware of the myriad presentations of JXG in order to make a correct diagnosis and avoid unnecessary investigations or treatment.

  3. The Giant Jet

    Neubert, T.; Chanrion, O.; Arnone, E.; Zanotti, F.; Cummer, S.; Li, J.; Füllekrug, M.; van der Velde, O.


    Thunderstorm clouds may discharge directly to the ionosphere in spectacular luminous jets - the longest electric discharges on our planet. The electric properties of jets, such as their polarity, conductivity, and currents, have been predicted by models, but are poorly characterized by measurements. Here we present an analysis of the first gigantic jet that with certainty has a positive polarity. The jet region in the mesosphere was illuminated by an unusual sprite discharge generated by a positive cloud-to-ground lightning flash shortly after the onset of the jet. The sprite appeared with elements in a ring at ~40 km distance around the jet, the elements pointing curving away from the jet. This suggests that the field close the jet partially cancels the field driving the sprite. From a simple model of the event we conclude that a substantial portion of the positive cloud potential must be carried to ~50 km altitude, which is also consistent with the observed channel expansion and the electromagnetic radiation associated with the jet. It is further shown that blue jets are likely to substantially modify the free electron content in the lower ionosphere because of increased electron attachment driven by the jet electric field. The model further makes clear the relationship between jets, gigantic jets, and sprites. This is the first time that sprites are used for sounding the properties of the mesosphere. The observations presented here will allow evaluation of theories for jet and gigantic jet generation and of their influence on the atmosphere-ionosphere system.

  4. Distribution and Population Status of the Giant Otter Pteronura brasiliensis in Bolivia

    Damme P. van


    Full Text Available The giant otter (Pteronura brasiliensis is one of the most endangered mammal species in the Neotropical region. In Bolivia, it has been reduced to very low population numbers as a result of poaching in the 40s and 70s. Recently, 14 researchers on the giant otter, who together estimated that around 350 individuals exist in Bolivia, published a preliminary distribution map. In this report, we briefly present the most recent information on the distribution and population status of this species in the Bolivian Del Plata and Amazon river basins. Moreover, we comment on the superposition of giant otter family groups, hydro-ecoregions, and National Parks. Finally, we present a short discussion on the possibilities of interchange between Bolivian giant otter subpopulations.

  5. Giant Arteriovenous Malformation of the Neck

    P. A. Dieng


    Full Text Available Arteriovenous malformations (AVM have a wide range of clinical presentations. Operative bleeding is one of the most hazardous complications in the surgical management of high-flow vascular malformations. In the cervical region, the presence of vital vascular structures, such as the carotid artery and jugular vein, may increase this risk. This is a case of massive arteriovenous malformation deforming the neck and the face aspect of this aged lady and growing for several years. A giant mass of the left neck occupied the carotid region and the subclavian region. The AVM was developed between the carotid arteries, jugular veins, and vertebral and subclavian vessels, with arterial and venous flux. The patient underwent surgery twice for the cure of that AVM. The first step was the ligation of the external carotid. Seven days later, the excision of the mass was done. In postoperative period the patient presented a peripheral facial paralysis which completely decreased within 10 days. The first ligation of the external carotid reduces significantly the blood flow into the AVM. It permitted secondarily the complete ablation of the AVM without major bleeding even though multiple ligations were done.

  6. Aberrant DNA methylation of cancer-related genes in giant breast fibroadenoma: a case report

    Orozco Javier I


    Full Text Available Abstract Introduction Giant fibroadenoma is an uncommon variant of benign breast lesions. Aberrant methylation of CpG islands in promoter regions is known to be involved in the silencing of genes (for example, tumor-suppressor genes and appears to be an early event in the etiology of breast carcinogenesis. Only hypermethylation of p16INK4a has been reported in non-giant breast fibroadenoma. In this particular case, there are no previously published data on epigenetic alterations in giant fibroadenomas. Our previous results, based on the analysis of 49 cancer-related CpG islands have confirmed that the aberrant methylation is specific to malignant breast tumors and that it is completely absent in normal breast tissue and breast fibroadenomas. Case presentation A 13-year-old Hispanic girl was referred after she had noted a progressive development of a mass in her left breast. On physical examination, a 10 × 10 cm lump was detected and axillary lymph nodes were not enlarged. After surgical removal the lump was diagnosed as a giant fibroadenoma. Because of the high growth rate of this benign tumor, we decided to analyze the methylation status of 49 CpG islands related to cell growth control. We have identified the methylation of five cancer-related CpG islands in the giant fibroadenoma tissue: ESR1, MGMT, WT-1, BRCA2 and CD44. Conclusion In this case report we show for the first time the methylation analysis of a giant fibroadenoma. The detection of methylation of these five cancer-related regions indicates substantial epigenomic differences with non-giant fibroadenomas. Epigenetic alterations could explain the higher growth rate of this tumor. Our data contribute to the growing knowledge of aberrant methylation in breast diseases. In this particular case, there exist no previous data regarding the role of methylation in giant fibroadenomas, considered by definition as a benign breast lesion.

  7. Hide and seek between Andromeda's halo, disk, and giant stream

    Clementini, Gisella; Federici, Luciana; Macario, Giulia; Beccari, Giacomo; Testa, Vincenzo; Cignoni, Michele; Marconi, Marcella; Ripepi, Vincenzo; Tosi, Monica; Bellazzini, Michele; Pecci, Flavio Fusi; Diolaiti, Emiliano; Cacciari, Carla; Marano, Bruno; Giallongo, Emanuele; Ragazzoni, Roberto; Di Paola, Andrea; Gallozzi, Stefano; Smareglia, Riccardo


    Photometry in B, V (down to V ~ 26 mag) is presented for two 23' x 23' fields of the Andromeda galaxy (M31) that were observed with the blue channel camera of the Large Binocular Telescope during the Science Demonstration Time. Each field covers an area of about 5.1kpc x 5.1kpc at the distance of M31 ((m-M)o ~ 24.4 mag), sampling, respectively, a northeast region close to the M31 giant stream (field S2), and an eastern portion of the halo in the direction of the galaxy minor axis (field H1). The stream field spans a region that includes Andromeda's disk and the giant stream, and this is reflected in the complexity of the color magnitude diagram of the field. One corner of the halo field also includes a portion of the giant stream. Even though these demonstration time data were obtained under non-optimal observing conditions the B photometry, acquired in time-series mode, allowed us to identify 274 variable stars (among which 96 are bona fide and 31 are candidate RR Lyrae stars, 71 are Cepheids, and 16 are bin...

  8. Discovery of Very High Energy Gamma-Ray Emission in the W 28 (G6.4-0.1) Region and Multiwavelength Comparisons

    Rowell, G.; /Adelaide U.; Brion, E.; /DAPNIA, Saclay; Reimer, O.; /Stanford U., HEPL /KIPAC, Menlo Park; Moriguchi, Y.; Fukui, Yasuo; /Nagoya U.; Djannati-Atai, A.; /APC, Paris; Funk, S.; /Stanford U., HEPL /KIPAC, Menlo Park


    H.E.S.S. observations of the old-age (>10{sup 4} yr; {approx} 0.5 degree diameter) composite supernova remnant (SNR)W28 reveal very high energy (VHE) {gamma}-ray emission situated at its northeastern and southern boundaries. The northeastern VHE source (HESS J1801-233) is in an area where W 28 is interacting with a dense molecular cloud, containing OH masers, local radio and X-ray peaks. The southern VHE sources (HESS J1800-240 with components labeled A, B and C) are found in a region occupied by several HII regions, including the ultracompact HII region W 28A2. Our analysis of NANTEN CO data reveals a dense molecular cloud enveloping this southern region, and our reanalysis of EGRET data reveals MeV/GeV emission centered on HESS J1801-233 and the northeastern interaction region.

  9. An ecological basis for managing giant sequoia ecosystems.

    Piirto, Douglas D; Rogers, Robert R


    A strategy for management of giant sequoia groves is formulated using a conceptual framework for ecosystem management recently developed by Region Five of the USDA Forest Service. The framework includes physical, biological, and social dimensions. Environmental indicators and reference variability for key ecosystem elements are discussed in this paper. The selected ecosystem elements include: 1) attitudes, beliefs, and values; 2) economics and subsistence; 3) stream channel morphology; 4) sediment; 5) water; 6) fire; 7) organic debris; and 8) vegetation mosaic. Recommendations are made for the attributes of environmental indicators that characterize these elements. These elements and associated indicators will define and control management activities for the protection, preservation, and restoration of national forest giant sequoia ecosystems.

  10. Cytogenetic study of the giant otter Pteronura brasiliensis Zimmermann 1780 (Carnivora, Mustelidae, Lutrinae

    Jorge Felipe Oliveira Franco-de-Sá


    Full Text Available The giant otter, Pteronura brasiliensis Zimmermann 1780 (Carnivora, Mustelidae, Lutrinae, was widely distributed in South America but stable populations are now only found in the Pantanal and Amazon regions and the species is classified as endangered. There is only one recognized species of giant otter, although two subspecies of doubtful value have also been cited in the literature. We present the first karyotype of four captive P. brasiliensis specimens, all of which posses 2n = 38 chromosomes as 14M+8SM+6ST+8A and one pair of sexual chromosomes. An heteromorphic secondary constriction, associated with the nucleolar organizer region (NOR, was seen on the long arms of chromosome pair 17. The C-banding technique revealed heterochromatin in the centromeric region of all the chromosomes and the NOR was C-banding positive. The giant otter presented the same diploid number as most mustelids, although its karyotype is quite species-specific.

  11. Giant magneto-resistance devices

    Hirota, Eiichi; Inomata, Koichiro


    This book deals with the application of giant magneto-resistance (GMR) effects to electronic devices. It will appeal to engineers and graduate students in the fields of electronic devices and materials. The main subjects are magnetic sensors with high resolution and magnetic read heads with high sensitivity, required for hard-disk drives with recording densities of several gigabytes. Another important subject is novel magnetic random-access memories (MRAM) with non-volatile non-destructive and radiation-resistant characteristics. Other topics include future GMR devices based on bipolar spin transistors, spin field-effect transistors (FETs) and double-tunnel junctions.



    @@ PetroChina announced a discovery of a giant oilfield in the beginning of May, which has a reserve of one billion tons, or about 7.35 billion barrels, the largest discovery in China over four decades. Of the reserves, the basically proven oil in place is 405 million tons with the average thickness of oil formations ranging between 80 meters and 100 meters. The oilfield lies in the Nanpu block of PetroChina Jidong Oilfield Company in Caofeidian industrial zone, north China's Hebei province. The area is expected to enjoy a better chance of becoming a national oil strategic reserve base following the discovery of the Nanpu Oilfield.

  13. On the Shoulders of Giants...


    On the shoulders of giantsI Basil A. Pruitt, Jr., MD and Todd E. Rasmussen, MD I n a letter dated February 5, 1676 (dated 1675 using the Julian...T.E.R.), Fort Sam Houston, San Antonio, TX. Address for reprints: Basil A. Pruitt, Jr, MD, Division of Trauma, Department of Surgery, The University...default.htm. 20. Moore FD. Edward Delos Churchill (1895Y1972). Ann Surg. 1973; 177:507Y508. 21. The Board for the Study of the Severely Wounded. The

  14. Internal rotation of red giants by asteroseismology

    Di Mauro, M P; Ventura, R; Stello, D; Beck, P G; Davies, G; Elsworth, Y; Garcıa, R A; Hekker, S; Mosser, B; Christensen-Dalsgaard, J; Bloemen, S; Catanzaro, G; De Smedt, K; Tkachenko, A


    We present an asteroseismic approach to study the dynamics of the stellar interior in red-giant stars by asteroseismic inversion of the splittings induced by the stellar rotation on the oscillation frequencies. We show preliminary results obtained for the red giant KIC4448777 observed by the space mission Kepler.

  15. Giant Rings in the CMB Sky

    Kovetz, Ely D; Itzhaki, Nissan


    We find a unique direction in the CMB sky around which giant rings have an anomalous mean temperature profile. This direction is in very close alignment with the afore measured anomalously large bulk flow direction. We argue that a cosmic defect seeded by a pre-inflationary particle could explain the giant rings, the large bulk flow and their alignment.

  16. Totally thrombosed giant anterior communicating artery aneurysm

    V R Roopesh Kumar


    Full Text Available Giant anterior communicating artery aneurysmsarerare. Apatient presented with visual dysfunction, gait ataxia and urinary incontinence. MRI showed a giant suprasellar mass.At surgery, the lesion was identified as being an aneurysm arising from the anterior communicating artery.The difficulty in preoperative diagnosis and relevant literature are reviewed.

  17. Surgical treatment for giant incisional hernia

    Eriksson, A; Rosenberg, J; Bisgaard, T


    INTRODUCTION: Repair for giant incisional hernias is a challenge due to unacceptable high morbidity and recurrence rates. Several surgical techniques are available, but all are poorly documented. This systematic review was undertaken to evaluate the existing literature on repair for giant incisio...... procedure and severely lack evidence-based research from high-quality, large-scaled randomised studies....

  18. Giant crystals inside mitochondria of equine chondrocytes.

    Nürnberger, S; Rentenberger, C; Thiel, K; Schädl, B; Grunwald, I; Ponomarev, I; Marlovits, St; Meyer, Ch; Barnewitz, D


    The present study reports for the first time the presence of giant crystals in mitochondria of equine chondrocytes. These structures show dark contrast in TEM images as well as a granular substructure of regularly aligned 1-2 nm small units. Different zone axes of the crystalline structure were analysed by means of Fourier transformation of lattice-resolution TEM images proving the crystalline nature of the structure. Elemental analysis reveals a high content of nitrogen referring to protein. The outer shape of the crystals is geometrical with an up to hexagonal profile in cross sections. It is elongated, spanning a length of several micrometres through the whole cell. In some chondrocytes, several crystals were found, sometimes combined in a single mitochondrion. Crystals were preferentially aligned along the long axis of the cells, thus appearing in the same orientation as the chondrocytes in the tissue. Although no similar structures have been found in the cartilage of any other species investigated, they have been found in cartilage repair tissue formed within a mechanically stimulated equine chondrocyte construct. Crystals were mainly located in superficial regions of cartilage, especially in joint regions of well-developed superficial layers, more often in yearlings than in adult horses. These results indicate that intramitochondrial crystals are related to the high mechanical stress in the horse joint and potentially also to the increased metabolic activity of immature individuals.

  19. Giant Omental Fibromatosis Presenting as Pelvic Mass

    Singh, Pradyumn; Jain, Neelesh; Jain, Jaswant; Kumar, Vijay


    Omental fibromatosis (abdominal desmoids) is a rare benign but locally aggressive neoplasm characterized by mass like or infiltrative growth of fibrous tissue. It usually arises from the abdominal wall or the extremities, however rarely it may also arise in the omentum, ileocolic mesentery, transverse or sigmoid mesocolon and ligamentum teres. Here, we present an 18-year-old male, who presented with lower abdominal pain and palpable lump in hypogastric region. Computed tomography of the abdomen showed large heterogeneous mass in lower abdomen, possibly arising from mesentery with regional adenopathy. Patient underwent exploratory laparotomy with a preoperative diagnosis of mesenteric tumour possibly gastrointestinal stromal tumour (GIST). Histopathological examination revealed the lesion as omental fibromatosis. To the best of our knowledge, very few cases of omental fibromatosis are noted in literature. Here, we describe a rare case of giant omental fibromatosis which resembled mesenteric GIST clinically but finally diagnosed as fibromatosis by histomorphology and immunohistochemistry (IHC). The present article describes fibromatosis of greater omentum and the difficulty in preoperative diagnosis, as it is frequently misdiagnosed as GIST. PMID:25859511

  20. Giant Planet Formation, Evolution, and Internal Structure

    Helled, Ravit; Podolak, Morris; Boley, Aaron; Meru, Farzana; Nayakshin, Sergei; Fortney, Jonathan J; Mayer, Lucio; Alibert, Yann; Boss, Alan P


    The large number of detected giant exoplanets offers the opportunity to improve our understanding of the formation mechanism, evolution, and interior structure of gas giant planets. The two main models for giant planet formation are core accretion and disk instability. There are substantial differences between these formation models, including formation timescale, favorable formation location, ideal disk properties for planetary formation, early evolution, planetary composition, etc. First, we summarize the two models including their substantial differences, advantages, and disadvantages, and suggest how theoretical models should be connected to available (and future) data. We next summarize current knowledge of the internal structures of solar- and extrasolar- giant planets. Finally, we suggest the next steps to be taken in giant planet exploration.


    Hatzes, Artie P. [Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg (Germany); Rauer, Heike, E-mail:, E-mail: [Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt, Rutherfordstrasse 2, D-12489 Berlin (Germany)


    We present the mass–density relationship (log M − log ρ) for objects with masses ranging from planets (M ≈ 0.01 M{sub Jup}) to stars (M > 0.08 M{sub ⊙}). This relationship shows three distinct regions separated by a change in slope in the log M − log ρ plane. In particular, objects with masses in the range 0.3 M{sub Jup}–60 M{sub Jup} follow a tight linear relationship with no distinguishing feature to separate the low-mass end (giant planets) from the high-mass end (brown dwarfs). We propose a new definition of giant planets simply based on changes in the slope of the log M versus log ρ relationship. By this criterion, objects with masses less than ≈0.3 M{sub Jup} are low-mass planets, either icy or rocky. Giant planets cover the mass range 0.3 M{sub Jup}–60 M{sub Jup}. Analogous to the stellar main sequence, objects on the upper end of the giant planet sequence (brown dwarfs) can simply be referred to as “high-mass giant planets,” while planets with masses near that of Jupiter can be called “low-mass giant planets.”.

  2. Corridor connecting giant panda habitats from north to south in the Min Mountains, Sichuan, China.

    Yin, Kaipu; Xie, Yan; Wu, Ning


    The giant panda faces severe threats from habitat fragmentation and isolation. Currently, giant panda populations have been fragmented into 30 habitat patches. The disappearance of isolated small populations and studies on the genetic diversity of various populations have shown that small isolated panda populations are at a high risk of dying out completely. Habitat fragmentation has seriously impaired the ability of the giant panda to resist climate changes and other natural disasters, such as large-scale, synchronous bamboo blooming. The Min Mountains have the largest population of pandas in China, numbering 581 individuals and accounting for 52% of the total (1114) in China. Geographic isolation means that giant pandas in the Min Mountains are divided into two populations (population A in the north and population B in the south). Population B, which had only 42 individuals in 1989, is severely threatened by high-density human populations and the loss of genetic diversity. However, we have identified an important corridor connecting the two populations. This paper explains the importance and the feasibility of reestablishing this corridor. Due to the special geographic locations of these two populations (two rivers block the migration of giant pandas between south and north), the corridor is the only passage for giant pandas in the region. Recent studies have also shown an increase of giant panda activity in the area of the corridor. However, vegetation in the corridor has been severely degraded. Bamboo forest must be restored in this area to provide food for the pandas during migration. The effects of human activities must be reduced in order to maintain panda habitat. We believe that a restored corridor will be of great benefit to the survival of giant pandas in the Min Mountains, especially for population B. Successful re-establishment of a corridor will be a valuable model for corridor construction in the future.

  3. Irradiated shocks in the W28 A2 massive star-forming region: a site for cosmic rays acceleration?

    Gusdorf, A; Gerin, M; Guesten, R


    The formation of massive stars play a crucial role in galaxies from numerous points of view. The protostar generates a strong ultraviolet radiation field that ionizes its surroundings, and it drives powerful shock waves in the neighbouring medium in the form of jets and bipolar outflows, whose structure can be partially organized by local, strong magnetic field. Such an ejection activity locally modifies the interstellar chemistry, contributing to the cycle of matter. It also significantly participates to the energetic balance of galaxies. In the latter stages of massive star formation, the protostar is surrounded by an ultra-compact HII region, and irradiates its bipolar outflows, where an intrinsically strong magnetic field structure is associated to the generally high densities. In the HII region, or in the bipolar outflows, the question of in situ cosmic rays acceleration can then be raised by the simultaneous presence of strong magnetic fields, significant ionization of the matter, and mechanical energy ...

  4. Giant Cutaneous Horn Overlying A Verruca at an Uncommon Site: Medical Marvel vs Superstitious Dilemma.

    Sanjeeva, Karthik Kathladka; Ali, Puttur Sainuddin Mohammed Ameer; Pinto, Malcolm; Rao, Srikar; Rai, Arvind Shivram


    Cutaneous horn has been a matter of discussion to mankind since time immemorial and a subject of fascination for the layman. There have been instances where certain groups saw it with angst and disgust, with a person having a large cutaneous horn on an exposed area getting a dismal look. We present a case of a 64-year-old man with a giant cutaneous horn over his left gluteal region. Cutaneous horns more commonly present in the sun-exposed areas. In our case it has presented in an uncommon site. The patient had delayed and denied medical treatment due to his superstitious beliefs, after having sought advice from faith healers leading to progression of the disease. This case has been presented for its giant size (rare variety), its location being over the gluteal region (photo-protected site) and its benign histopathology suggestive of wart in spite of the giant size.

  5. Photophoresis boosts giant planet formation

    Teiser, Jens


    In the core accretion model of giant planet formation, a solid protoplanetary core begins to accrete gas directly from the nebula when its mass reaches about 5 earth masses. The protoplanet has at most a few million years to reach runaway gas accretion, as young stars lose their gas disks after 10 million years at the latest. Yet gas accretion also brings small dust grains entrained in the gas into the planetary atmosphere. Dust accretion creates an optically thick protoplanetary atmosphere that cannot efficiently radiate away the kinetic energy deposited by incoming planetesimals. A dust-rich atmosphere severely slows down atmospheric cooling, contraction, and inflow of new gas, in contradiction to the observed timescales of planet formation. Here we show that photophoresis is a strong mechanism for pushing dust out of the planetary atmosphere due to the momentum exchange between gas and dust grains. The thermal radiation from the heated inner atmosphere and core is sufficient to levitate dust grains and to ...


    Abdalla, Rene Jorge; Cohen, Moisés; Nóbrega, Jezimar; Forgas, Andrea


    Synovial giant cell tumor is a benign neoplasm, rarely reported in the form of malignant metastasis. Synovial giant cell tumor most frequently occurs on the hand, and, most uncommon, on the ankle and knee. In the present study, the authors describe a rare case of synovial giant cell tumor on the knee as well as the treatment approach. Arthroscopy has been shown, in this case, to be the optimal method for treating this kind of lesion, once it allowed a less aggressive approach, while providing good visualization of all compartments of knee joint and full tumor resection.

  7. Giant Cell Tumor: Role of Conservative Treatment

    Anatolii Diedkov[1; Pavlo Kovalchuk[1; Marija Kukushkina[2; Sergey Bojchuk[1; Viktor Kostyuk[1


    Giant cell tumor is aggressive bone tumor. Surgical treatment is considered to be the only effective method of treatment ofthese tumors. The problem of inoperable patients with giant cell tumors is a challenge. A total of 8 patients had giant cell bone tumorsof pelvis and sacrum. 3 patients were treated by bisphosphonates, radiation therapy and embolization of tumor-nutrient arteries. 5patients received denosumab. The efficiency was assessed according to clinical data and CT scan control. Median follow up is 28months. All 8 patients had reduction of pain intensity. Treatment with denosumab demonstrated more than 30% tumor regression. Allof the patients are in remission.

  8. Giant choledochal calculosis: Surgical treatment

    Hasan Bektas


    Full Text Available Context: Gallstone disease is one of the most common surgical pathologies. Choledocholithiasis may occur in some of these cases and require surgical intervention. Although there are relatively non-invasive procedures such as endoscopic retrograde cholangiopancreatography (ERCP, this technique is usually unsuccessful in patients with stones larger than 10 mm. In our case, we aimed to report a giant choledochal stone (15 cm × 4.5 cm, which is rare in surgical practice and our treatment with open surgery. Case Report: The patient was a 59-year-old woman. Magnetic resonance cholangiopancreatography (MRCP had showed a hydropic gallbladder with an excessively dilated CBD and a 110 mm × 41 mm stone. In the operation, an excessively dilated CBD was seen and after choledochotomy and a very large calculus that filled CBD completely. Choledochotomy incision was carried forward and a T-tube choledochostomy with choledochoduodenostomy (CD was performed. The patient was discharged without any complications on postoperative 8 th day. Conclusion: Benign gallstone disease is a multifactorial process, with risk factors such as obesity, hemolytic diseases, diabetes mellitus, and pregnancy. Risk factors for choledocholithiasis are similar to those for gallstone disease. MRCP is a non-invasive technique in detecting choledocholithiasis. The gold standard intervention for CBD stones is ERCP. Stones in CBD may reach very considerable dimensions without causing serious symptoms. The most common symptom is jaundice. During preoperative radiological examination, giant stones may be interfered with malignancies. Surgeons should obey conventional algorithms in diagnosis and open surgery must be kept in mind in earlier stages without being too insistent on endoscopic interventions.

  9. Giant comets and mass extinctions of life

    Napier, W. M.


    I find evidence for clustering in age of well-dated impact craters over the last 500 Myr. At least nine impact episodes are identified, with durations whose upper limits are set by the dating accuracy of the craters. Their amplitudes and frequency are inconsistent with an origin in asteroid breakups or Oort cloud disturbances, but are consistent with the arrival and disintegration in near-Earth orbits of rare, giant comets, mainly in transit from the Centaur population into the Jupiter family and Encke regions. About 1 in 10 Centaurs in Chiron-like orbits enter Earth-crossing epochs, usually repeatedly, each such epoch being generally of a few thousand years' duration. On time-scales of geological interest, debris from their breakup may increase the mass of the near-Earth interplanetary environment by two or three orders of magnitude, yielding repeated episodes of bombardment and stratospheric dusting. I find a strong correlation between these bombardment episodes and major biostratigraphic and geological boundaries, and propose that episodes of extinction are most effectively driven by prolonged encounters with meteoroid streams during bombardment episodes. Possible mechanisms are discussed.

  10. Giant comets and mass extinctions of life

    Napier, W M


    I find evidence for clustering in age of well-dated impact craters over the last 500 Myr. At least nine impact episodes are identified, with durations whose upper limits are set by the dating accuracy of the craters. Their amplitudes and frequency are inconsistent with an origin in asteroid breakups or Oort cloud disturbances, but are consistent with the arrival and disintegration in near-Earth orbits of rare, giant comets, mainly in transit from the Centaur population into the Jupiter family and Encke regions. About 1 in 10 Centaurs in Chiron-like orbits enter Earth-crossing epochs, usually repeatedly, each such epoch being generally of a few thousand years duration. On time-scales of geological interest, debris from their breakup may increase the mass of the near-Earth interplanetary environment by two or three orders of magnitude, yielding repeated episodes of bombardment and stratospheric dusting. I find a strong correlation between these bombardment episodes and major biostratigraphic and geological boun...

  11. Manganese abundances in Galactic bulge red giants

    Barbuy, B; Zoccali, M; Minniti, D; Renzini, A; Ortolani, S; Gomez, A; Trevisan, M; Dutra, N


    Manganese is mainly produced in type II SNe during explosive silicon burning, in incomplete Si-burning regions, and depends on several nucleosynthesis environment conditions, such as mass cut beween the matter ejected and falling back onto the remnant, electron and neutron excesses, mixing fallback, and explosion energy. Manganese is also produced in type Ia SNe. The aim of this work is the study of abundances of the iron-peak element Mn in 56 bulge giants, among which 13 are red clump stars. Four bulge fields along the minor axis are inspected. The study of abundances of Mn-over-Fe as a function of metallicity in the Galactic bulge may shed light on its production mechanisms. High-resolution spectra were obtained using the FLAMES+UVES spectrograph on the Very Large Telescope. The spectra were obtained within a program to observe 800 stars using the GIRAFFE spectrograph, together with the present UVES spectra. We aim at identifying the chemical evolution of manganese, as a function of metallicity, in the Gala...

  12. Liquid Water Oceans in Ice Giants

    Wiktorowicz, S J; Wiktorowicz, Sloane J.; Ingersoll, Andrew P.


    Aptly named, ice giants such as Uranus and Neptune contain significant amounts of water. While this water cannot be present near the cloud tops, it must be abundant in the deep interior. We investigate the likelihood of a liquid water ocean existing in the hydrogen-rich region between the cloud tops and deep interior. Starting from an assumed temperature at a given upper tropospheric pressure (the photosphere), we follow a moist adiabat downward. The mixing ratio of water to hydrogen in the gas phase is small in the photosphere and increases with depth. The mixing ratio in the condensed phase is near unity in the photosphere and decreases with depth; this gives two possible outcomes. If at some pressure level the mixing ratio of water in the gas phase is equal to that in the deep interior, then that level is the cloud base. Alternately, if the mixing ratio of water in the condensed phase reaches that in the deep interior, then the surface of a liquid ocean will occur. We find that Neptune is both too warm (ph...

  13. Quasar feedback revealed by giant molecular outflows

    Feruglio, Chiara; Piconcelli, Enrico; Menci, Nicola; Aussel, Herve'; Lamastra, Alessandra; Fiore, Fabrizio


    In the standard scenario for galaxy evolution the transformation of young star-forming galaxies into red bulge-dominated spheroids, where star formation has been quenched, is often explained by invoking a strong negative feedback generated by accretion onto a central super-massive black hole. The depletion of gas resulting from quasar-driven outflows should eventually stop star-formation across the host galaxy and lead to the black hole "suicide" for starvation. Direct observational evidence for a major quasar feedback onto the host galaxy is still missing, since outflows previously observed in quasars are associated with the ionized component of the gas, which only accounts for a minor fraction of the total gas content, and typically occur in the central regions. We used the IRAM PdBI to observe the CO(1-0) transition in Mrk 231, the closest quasar known. We detect broad wings of the CO line, with velocities up to 750 km/s and spatially resolved on the kpc scale. Such broad CO wings trace a giant molecular o...

  14. Unravelling tidal dissipation in gaseous giant planets

    Guenel, Mathieu; Remus, Françoise


    Tidal dissipation in planetary interiors is one of the key physical mechanisms that drive the evolution of star-planet and planet-moon systems. New constraints are now obtained both in the Solar and exoplanetary systems. Tidal dissipation in planets is intrinsically related to their internal structure. In particular, fluid and solid layers behave differently under tidal forcing. Therefore, their respective dissipation reservoirs have to be compared. In this letter, we compute separately the contributions of the potential dense rocky/icy core and the convective fluid envelope of gaseous giant planets, as a function of core size and mass. We then compare the associated dissipation reservoirs, by evaluating the frequency-average of the imaginary part of the Love numbers $k^2_2$ in each region. In the case of Jupiter and Saturn-like planets, we show that the viscoelastic dissipation in the core could dominate the turbulent friction acting on tidal inertial waves in the envelope. However, the fluid dissipation wou...

  15. The morphology and fine structure of the giant interneurons of the wood cricket Nemobius sylvestris.

    Insausti, T C; Lazzari, C R; Casas, J


    The structural and ultrastructural characteristics of giant interneurons in the terminal abdominal ganglion of the cricket Nemobius sylvestris were investigated by means of cobalt and fluorescent dye backfilling and transmission electron microscopy. The projections of the 8 eight pairs of the biggest ascending interneurons (giant interneurons) are described in detail. The somata of all interneurons analyzed are located contralateral to their axons, which project to the posterior region of the terminal ganglion and arborise in the cercal glomerulus. Neuron 7-1a is an exception, because its arborisation is restricted to the anterior region of the ganglion. The fine structure of giant interneurons shows typical features of highly active cells. We observed striking indentations in the perineural layer, enabling the somata of the giant interneurons to be very close to the haemolymph. The cercal glomerulus exhibits a high diversity of synaptic contacts (i.e. axo-dendritic, axo-axonic, dendro-axonic, and dendro-dendritic), as well as areas of tight junctions. Electrical synapses seem to be present, as well as mixed synapses. The anatomical organization of the giant interneurons is finally discussed in terms of functional implications and on a comparative basis.


    Smith, Verne V.; Cunha, Katia [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Shetrone, Matthew D. [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Meszaros, Szabolcs; Allende Prieto, Carlos [Instituto d' Astrofisica de Canarias, E-38205, La Laguna, Tenerife (Spain); Bizyaev, Dmitry [Apache Point Observatory, Sunspot, NM 88349 (United States); Garcia Perez, Ana; Majewski, Steven R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Schiavon, Ricardo [Astrophysics Research Institute, Liverpool John Moores University, Liverpool L3 5UX (United Kingdom); Holtzman, Jon [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Johnson, Jennifer A., E-mail: [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)


    High-resolution H-band spectra of five bright field K, M, and MS giants, obtained from the archives of the Kitt Peak National Observatory Fourier transform spectrometer, are analyzed to determine chemical abundances of 16 elements. The abundances were derived via spectrum synthesis using the detailed linelist prepared for the Sloan Digital Sky Survey III Apache Point Galactic Evolution Experiment (APOGEE), which is a high-resolution near-infrared spectroscopic survey to derive detailed chemical abundance distributions and precise radial velocities for 100,000 red giants sampling all Galactic stellar populations. The red giant sample studied here was chosen to probe which chemical elements can be derived reliably from the H-band APOGEE spectral region. These red giants consist of two K-giants ({alpha} Boo and {mu} Leo), two M-giants ({beta} And and {delta} Oph), and one thermally pulsing asymptotic giant branch (TP-AGB) star of spectral type MS (HD 199799). Measured chemical abundances include the cosmochemically important isotopes {sup 12}C, {sup 13}C, {sup 14}N, and {sup 16}O, along with Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. The K and M giants exhibit the abundance signature of the first dredge-up of CN-cycle material, while the TP-AGB star shows clear evidence of the addition of {sup 12}C synthesized during {sup 4}He-burning thermal pulses and subsequent third dredge-up. A comparison of the abundances derived here with published values for these stars reveals consistent results to {approx}0.1 dex. The APOGEE spectral region and linelist is thus well suited for probing both Galactic chemical evolution, as well as internal nucleosynthesis and mixing in populations of red giants via high-resolution spectroscopy.



    The ingestion of giant freshwater prawn, Chinese prawn and giant tiger prawn had continuity and the ingestion high peak occurred at night. Light and temperature had significant effects on the daily ingestion rate (DIR) of giant freshwater prawn Macrobrachium rosenbergii. Red light and blue light favorably induced favorable ingestion. In the adaptive range of temperature, the DIR increased with rising temperature and feeding frequency, but decreased with rising body weight.

  18. Sequential Star Formation in RCW 34: A Spectroscopic Census of the Stellar Content of High-mass Star-forming Regions

    Bik, A; Waters, L B F M; Horrobin, M; Henning, Th; Vasyunina, T; Beuther, H; Linz, H; Kaper, L; Ancker, M van den; Lenorzer, A; Churchwell, E; Kurtz, S; Kouwenhoven, M B N; Stolte, A; de Koter, A; Thi, W- F; Comeron, F; Waelkens, Ch


    We present VLT/SINFONI integral field spectroscopy of RCW 34 along with Spitzer/IRAC photometry of the surroundings. RCW 34 consists of three different regions. A large bubble has been detected on the IRAC images in which a cluster of intermediate- and low-mass class II objects is found. At the northern edge of this bubble, an HII region is located, ionized by 3 OB stars. Intermediate mass stars (2 - 3 Msun) are detected of G- and K- spectral type. These stars are still in the pre-main sequence (PMS) phase. North of the HII region, a photon-dominated region is present, marking the edge of a dense molecular cloud traced by H2 emission. Several class 0/I objects are associated with this cloud, indicating that star formation is still taking place. The distance to RCW 34 is revised to 2.5 +- 0.2 kpc and an age estimate of 2 - 1 Myrs is derived from the properties of the PMS stars inside the HII region. The most likely scenario for the formation of the three regions is that star formation propagates from South to ...

  19. Simulation of an Ice Giant-style Dynamo

    Soderlund, K. M.; Aurnou, J. M.


    The Ice Giants, Uranus and Neptune, are unique in the solar system. These planets are the only known bodies to have multipolar magnetic fields where the quadrupole and octopole components have strengths comparable to or greater than that of the dipole. Cloud layer observations show that the planets also have zonal (east-west) flows that are fundamentally different from the banded winds of Jupiter and Saturn. The surface winds are characterized by strong retrograde equatorial jets that are flanked on either side by prograde jets at high latitudes. Thermal emission measurements of Neptune show that the surface energy flux pattern peaks in the equatorial and polar regions with minima at mid-latitudes. (The measurements for Uranus cannot adequately resolve the emission pattern.) The winds and magnetic fields are thought to be the result of convection in the planetary interior, which will also affect the heat flux pattern. Typically, it is implicitly assumed that the zonal winds are generated in a shallow layer, separate from the dynamo generation region. However, if the magnetic fields are driven near the surface, a single region can simultaneously generate both the zonal flows and the magnetic fields. Here, we present a novel numerical model of an Ice Giant-style dynamo to investigate this possibility. An order unity convective Rossby number (ratio of buoyancy to Coriolis forces) has been chosen because retrograde equatorial jets tend to occur in spherical shells when the effects of rotation are relatively weak. Our modeling results qualitatively reproduce all of the structural features of the global dynamical observations. Thus, a self-consistent model can generate magnetic field, zonal flow, and thermal emission patterns that agree with those of Uranus and Neptune. This model, then, leads us to hypothesize that the Ice Giants' zonal flows and magnetic fields are generated via dynamically coupled deep convection processes.

  20. Giant nontraumatic intradiploic arachnoid cyst in a young male*

    Sharma, Rajesh; Gupta, Puneet; Mahajan, Manik; Sharma, Poonam; Gupta, Anchal; Khurana, Arti


    Intradiploic arachnoid cysts have scarcely been reported in the literature, most reported cases being secondary to trauma. Nontraumatic arachnoid cysts are quite rare and have been reported mostly in adults. Here, we report the case of a 16-year-old male presenting with a slowly growing mass in the occipital region and intermittent headaches. On the basis of the findings of X-rays, computed tomography scans, and magnetic resonance imaging scans of the head, the mass was diagnosed as a giant intradiploic arachnoid cyst. PMID:27818549