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Sample records for carina nebula outflow

  1. [Fe II] 1.64 um Features of Jets and Outflows from Young Stellar Objects in the Carina Nebula

    CERN Document Server

    Shinn, Jong-Ho; Lee, Jae-Joon; Lee, Ho-Gyu; Kim, Hyun-Jeong; Koo, Bon-Chul; Sung, Hwankyung; Chun, Moo Young; Lyo, A -Ran; Moon, Dae-Sik; Kyeong, Jaemann; Park, Byeong-Gon; Hur, Hyeonoh; Lee, Yong-Hyun

    2013-01-01

    We present [Fe II] 1.64 {\\mu}m imaging observations for jets and outflows from young stellar objects (YSOs) over the northern part (~ 24'x45') of the Carina Nebula, a massive star forming region. The observations were performed with IRIS2 of Anglo-Australian Telescope and the seeing was ~1.5"+-0.5". Eleven jet and outflow features are detected at eight different regions, and are named as Ionized Fe Objects (IFOs). One Herbig-Haro object candidate missed in Hubble Space Telescope H{\\alpha} observations is newly identified as HHc-16, referring our [Fe II] images. IFOs have knotty or longish shapes, and the detection rate of IFOs against previously identified YSOs is 1.4 %, which should be treated as a lower limit. Four IFOs show an anti-correlated peak intensities in [Fe II] and H{\\alpha}, where the ratio I([Fe II])/I(H{\\alpha}) is higher for longish IFOs than for knotty IFOs. We estimate the outflow mass loss rate from the [Fe II] flux, using two different methods. The jet-driving objects are identified for th...

  2. A Smoking Gun in the Carina Nebula

    Science.gov (United States)

    Hamaguchi, Kenji; Corcoran, Michael F.; Ezoe, Yuichiro; Townsley, Leisa; Broos, Patrick; Gruendl, Robert; Vaidya, Kaushar; White, Stephen M.; Petre, Rob; Chu, You-Hua

    2009-01-01

    The Carina Nebula is one of thc youngest, most active sites of massive star formation in our Galaxy. In this nebula, we have discovered a bright X-ray source that has persisted for approx.30 years. The soft X-ray spectrum. consistent with kT approx.130 eV blackbody radiation with mild extinction, and no counterpart in the near- and mid-infrared wavelengths indicate that it is a, approx. 10(exp 6)-year-old neutron star housed in the Carina Nebula. Current star formation theory does not suggest that the progenitor of the neutron star and massive stars in the Carina Nebula, in particular (eta)Car, are coeval. This result demonstrates that the Carina Nebula experienced at least two major episodes of massive star formation. The neutron star would be responsible for remnants of high energy activity seen in multiple wavelengths.

  3. Forming Planets in the Hostile Carina Nebula

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    Can protoplanetary disks form and be maintained around low-mass stars in the harsh environment of a highly active, star-forming nebula? A recent study examines the Carina nebula to answer this question.Crowded ClustersStars are often born in clusters that contain both massive and low-mass stars. The most massive stars in these clusters emit far-ultraviolet and extreme-ultraviolet light that irradiates the region around them, turning the surrounding area into a hostile environment for potential planet formation.Planet formation from protoplanetary disks typically requires timescales of at least 12 million years. Could the harsh radiation from massive stars destroy the protoplanetary disks around low-mass stars by photoevaporation before planets even have a chance to form?Artists impression of a protoplanetary disk. Such disks can be photoevaporated by harsh ultraviolet light from nearby massive stars, causing the disk to be destroyed before planets have a chance to form within them. [ESO/L. Calada]Turning ALMA Toward CarinaA perfect case study for exploring hostile environments is the Carina nebula, located about 7500 lightyears away and home to nearly 100 O-type stars as well as tens of thousands of lower-mass young stars. The Carina population is ~14 Myr old: old enough to form planets within protoplanetary disks, but also old enough that photoevaporation could already have wreaked havoc on those disks.Due to the dense stellar populations in Carinas clusters, this is a difficult region to explore, but the Atacama Large Millimeter-submillimeter Array (ALMA) is up to the task. In a recent study, a team of scientists led by Adal Mesa-Delgado (Pontifical Catholic University of Chile) made use of ALMAs high spatial resolution to image four regions spaced throughout Carina, searching for protoplanetary disks.Detections and Non-DetectionsTwo evaporating gas globules in the Carina nebula, 104-593 and 105-600, that each contain a protoplanetary disk. The top panels are

  4. HESS observations of the Carina nebula and its enigmatic colliding wind binary Eta Carinae

    Science.gov (United States)

    HESS Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Becherini, Y.; Becker, J.; Bernlöhr, K.; Birsin, E.; Biteau, J.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Cologna, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gallant, Y. A.; Garrigoux, T.; Gast, H.; Gérard, L.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Göring, D.; Grondin, M.-H.; Häffner, S.; Hague, J. D.; Hahn, J.; Hampf, D.; Harris, J.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Khélifi, B.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Krayzel, F.; Laffon, H.; Lamanna, G.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, G.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Mohamed, M.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Perez, J.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sheidaei, F.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.; Montmerle, T.

    2012-07-01

    The massive binary system Eta Carinae and the surrounding H II complex, the Carina nebula, are potential particle acceleration sites from which very high energy (VHE; E≥ 100 GeV) γ-ray emission could be expected. This paper presents data collected during VHE γ-ray observations with the HESS telescope array from 2004 to 2010, which cover a full orbit of Eta Carinae. In the 33.1-h data set no hint of significant γ-ray emission from Eta Carinae has been found and an upper limit on the γ-ray flux of ? (99 per cent confidence level) is derived above the energy threshold of 470 GeV. Together with the detection of high energy (HE; 0.1 ≤E≤ 100 GeV) γ-ray emission by the Fermi Large Area Telescope up to 100 GeV, and assuming a continuation of the average HE spectral index into the VHE domain, these results imply a cut-off in the γ-ray spectrum between the HE and VHE γ-ray range. This could be caused either by a cut-off in the accelerated particle distribution or by severe γ-γ absorption losses in the wind collision region. Furthermore, the search for extended γ-ray emission from the Carina nebula resulted in an upper limit on the γ-ray flux of ? (99 per cent confidence level). The derived upper limit of ˜23 on the cosmic ray enhancement factor is compared with results found for the old-age mixed-morphology supernova remnant W28.

  5. The bipolar structure of the LBV nebula around HR Carinae

    CERN Document Server

    Weis, K; Bomans, D J; Chu, Y H; Joner, M D

    1997-01-01

    HR Carinae is one of the few Luminous Blue Variables (LBVs) in the Galaxy. It has a nebula that appears bipolar. We have obtained imaging and high-dispersion, long-slit echelle data of the HR Car nebula, and confirmed that it is a bipolar nebula. Its polar axis lies along the position angle of 125 +- 5 degree; each lobe has, at a distance of 5 kpc a diameter of about 0.65 pc and a line-of-sight expansion velocity of 75-150 km/sec. Beside the expanding bipolar lobes, a number of [NII]-bright knots are detected. These knots have lower expansion velocities than the lobes and are detected only within the projected boundary of the lobes. These knots are most likely nitrogen-enriched material ejected by HR Car. On a larger scale, a funnel-shaped nebula is detected at 2.5" northwest of HR Car. The axis of the funnel is roughly aligned with the polar axis of the HR Car nebula, suggesting that HR Car may be responsible for the ionization and shaping of this nebula. Future observations of kinematics and abundances are ...

  6. Submillimeter and Far-Infrared Observations of the Carina Nebula

    Science.gov (United States)

    Oberst, Thomas E.; Parshley, S. C.; Nikola, T.; Stacey, G. J.; Loehr, A.; Lane, A. P.; Stark, A. A.; Kamenetzky, J.

    2011-05-01

    We present the results of a 250 arcmin2 mapping of the 205 μm [NII] fine-structure emission over the northern Carina Nebula, including the Car I and Car II HII regions. Spectra were obtained using the South Pole Imaging Fabry-Perot Interferometer (SPIFI) at the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) at South Pole. We supplement the 205 μm data with new reductions of far-IR fine-structure spectra from the Infrared Space Observatory (ISO) in 63 μm [OI], 122 μm [NII], 146 μm [OI], and 158 μm [CII]. Morphological comparisons are made with optical, radio continuum and CO maps. The 122 [NII] / 205 [NII] line ratio is used to probe the density of the low-ionization gas, and the 158 [C II] / 205 [NII] line ratio is used to probe the fraction of C+ arising from photodissociation regions (PDRs). From the [OI] and [CII] data, we construct a PDR model of Carina following Kaufman et al. (1999). When the PDR properties are compared with other sources, Carina is found to be more akin to 30 Doradus than Galactic star-forming regions such as the Orion Bar, M17, or W49; this is consistent with the view of Carina as a more evolved region, where much of the parent molecular cloud has been ionized or swept away. These data constitute the first ever ground-based detection of the 205 μm [NII] line, and only the third detection overall since those of the COBE FIRAS and the KAO in the early 1990s.

  7. Kinematics of powerful jets from intermediate-mass protostars in the Carina nebula

    CERN Document Server

    Reiter, Megan

    2014-01-01

    We present measurements of proper motions and radial velocities of four powerful Herbig-Haro (HH) jets in the Carina nebula: HH 666, HH 901, HH 902, and HH 1066. Two epochs of Hubble Space Telescope (HST) imaging separated by a time baseline of ~4.4 years provide proper motions that allow us to measure the transverse velocities of the jets, while ground-based spectra sample their Doppler velocities. Together these yield full three-dimensional space velocities. Aside from HH 666, their identification as outflows was previously inferred only from morphology in images. Proper motions now show decisively that these objects are indeed jets, and confirm that the intermediate-mass protostars identified as the candidate driving sources for HH 666 and HH 1066 are indeed the origin of these outflows. The appearance of two new knots in the HH 1066 jet suggest recent (~35 yr) changes in the accretion rate, underscoring the variable nature of accretion and outflow in the formation of intermediate-mass stars. In fact, kine...

  8. The Trumpler 14 photodissociation region in the Carina Nebula

    Science.gov (United States)

    Brooks, K. J.; Cox, P.; Schneider, N.; Storey, J. W. V.; Poglitsch, A.; Geis, N.; Bronfman, L.

    2003-12-01

    We report the results of observations of the fine-structure emission lines [C II] 158 μm and [O I] 63 μm using FIFI on the Kuiper Airborne Observatory (KAO) and the Long Wavelength Spectrometer (LWS) on board ISO, towards the molecular cloud associated with the stellar cluster Trumpler 14 (Tr 14) in the Carina Nebula. These data are compared with selected CO and CS transitions obtained with the SEST as well as IRAS and MSX images to produce a detailed view of the morphology and the physical conditions prevailing in the photodissociation region (PDR) at the interface between the ionized gas and the molecular dust lane. The relative intensity distribution observed for the various tracers is consistent with the stratification expected for a molecular cloud seen edge-on and exposed to a radiation field of ~ 104 G_0, which is dominated by the most massive stars of Tr 14. The grain photoelectric heating efficiency, \\epsilon, is estimated to be ~5 x 10-3 and is comparable to other galactic PDRs. The molecular gas has a complicated velocity structure with a high velocity dispersion resulting from the impact of the stellar winds arising from Tr 14. There is evidence of small-scale clumping with a very low volume filling factor. Despite the rich concentration of massive O stars in Tr 14 we find that the parameters of the PDR are much less-extreme than those of the Orion and M 17 massive star-forming regions.

  9. H.E.S.S. observations of the Carina nebula and its enigmatic colliding wind binary Eta Carinae

    CERN Document Server

    Abramowski, A; Aharonian, F; Akhperjanian, A G; Anton, G; Balzer, A; Barnacka, A; Becherini, Y; Becker, J; Bernlöhr, K; Birsin, E; Biteau, J; Bochow, A; Boisson, C; Bolmont, J; Bordas, P; Brucker, J; Brun, F; Brun, P; Bulik, T; Büsching, I; Carrigan, S; Casanova, S; Cerruti, M; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Cologna, G; Conrad, J; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Egberts, K; Eger, P; Espigat, P; Fallon, L; Fegan, S; Feinstein, F; Fernandes, M V; Fiasson, A; Fontaine, G; Förster, A; Füßling, M; Gallant, Y A; Garrigoux, T; Gast, H; Gèrard, L; Giebels, B; Glicenstein, J F; Glück, B; Göring, D; Grondin, M -H; Häffner, S; Hague, J D; Hahn, J; Hampf, D; Harris, J; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hillert, A; Hinton, J A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Jacholkowska, A; Jahn, C; Jamrozy, M; Jung, I; Kastendieck, M A; Katarzyński, K; Katz, U; Kaufmann, S; Khélifi, B; Klochkov, D; Kluźniak, W; Kneiske, T; Komin, Nu; Kosack, K; Kossakowski, R; Krayzel, F; Laffon, H; Lamanna, G; Lenain, J -P; Lennarz, D; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Masbou, J; Maurin, G; Maxted, N; Mayer, M; McComb, T J L; Medina, M C; Méhault, J; Moderski, R; Mohamed, M; Moulin, E; Naumann, C L; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Nguyen, N; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Wilhelmi, E de Oña; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Arribas, M Paz; Pekeur, N W; Pelletier, G; Perez, J; Petrucci, P -O; Peyaud, B; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raue, M; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sheidaei, F; Skilton, J L; Sol, H; Spengler, G; Stawarz, Ł; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Szostek, A; Tavernet, J -P; Terrier, R; Tluczykont, M; Valerius, K; van Eldik, C; Vasileiadis, G; Venter, C; Viana, A; Vincent, P; Völk, H J; Volpe, F; Vorobiov, S; Vorster, M; Wagner, S J; Ward, M; White, R; Wierzcholska, A; Zacharias, M; Zajczyk, A; Zdziarski, A A; Zech, A; Zechlin, H -S; Montmerle, T

    2012-01-01

    The massive binary system Eta Carinae and the surrounding HII complex, the Carina Nebula, are potential particle acceleration sites from which very-high-energy (VHE; E > 100 GeV) \\gamma-ray emission could be expected. This paper presents data collected during VHE \\gamma-ray observations with the H.E.S.S. telescope array from 2004 to 2010, which cover a full orbit of Eta Carinae. In the 33.1-hour data set no hint of significant \\gamma-ray emission from Eta Carinae has been found and an upper limit on the \\gamma-ray flux of 7.7 x 10-13 ph cm-2 s-1 (99% confidence level) is derived above the energy threshold of 470 GeV. Together with the detection of high-energy (HE; 0.1 GeV > E > 100 GeV) \\gamma-ray emission by the Fermi-LAT up to 100 GeV, and assuming a continuation of the average HE spectral index into the VHE domain, these results imply a cut-off in the \\gamma-ray spectrum between the HE and VHE \\gamma-ray range. This could be caused either by a cut-off in the accelerated particle distribution or by severe \\...

  10. Deep wide-field near-infrared survey of the Carina Nebula

    CERN Document Server

    Preibisch, Thomas; Kuderna, Benjamin; Ohlendorf, Henrike; King, Robert R; Hodgkin, Simon; Irwin, Mike; Lewis, James R; McCaughrean, Mark J; Zinnecker, Hans

    2011-01-01

    (abbreviated) We used HAWK-I at the ESO VLT to produce a near-infrared survey of the Carina Nebula that is deep enough to detect the full low-mass stellar population. The results of a recent deep X-ray survey are used to distinguish between young stars in Carina and background contaminants. We find that the ages of the low-mass stars (derived from color-magnitude diagrams of the invidual cluster in the Carina Nebula) agree with previous age estimates for the massive stars. About 3200 of the X-ray selected stars have masses >= 1 Msun; this number is in good agreement with extrapolations of the field IMF based on the number of high-mass stars and shows that there is no deficit of low-mass stars. The near-infrared excess fractions for the stellar populations in Carina are lower than typical for other, less massive clusters of similar age, suggesting a faster timescale of circumstellar disk dispersal than in the more quiescent regions, most likely due to the very high level of massive star feedback. Narrow-band i...

  11. Interaction of planetary nebulae, Eta-Carinae and supernova remnants with the Interstellar Medium

    CERN Document Server

    Zaninetti, L

    2012-01-01

    The image of planetary nebulae (PN), supernova remnant (SNR) and Eta-Carinae is made by three different physical processes. The first process is the expansion of the shell that can be modeled by the canonical laws of motion in the spherical case and by the momentum conservation when gradients of density are present in the interstellar medium. The quality of the simulations is introduced along one direction as well along many directions. The second process is the diffusion of particles that radiate from the advancing layer. The 3D diffusion from a sphere, the 1D diffusion with drift and 1D random walk are analyzed. The third process is the composition of the image through an integral operation along the line of sight. The developed framework is applied to three PN which are A39, the Ring nebula and the etched hourglass nebula MyCn 18, the hybrid object Eta-Carinae, and to two SNR which are SN 1993J and SN 1006. In all the considered cases a careful comparison between the observed and theoretical profiles in in...

  12. Collimated Outflows in the Stingray Nebula (He 3-1357)

    Science.gov (United States)

    Bobrowsky, M.; Sahu, K. C.; Parthasarathy, M.; Garcia-Lario, P.

    1997-12-01

    Observations over the past four decades have revealed significant changes in the spectrum of the Stingray Nebula (He 3-1357). Here we present HST images and spectra showing the most recent developments. In 1950, Henize saw only Hα in emission; but more recent observations by Parthasarathy et al. in 1992 showed strong forbidden lines consistent with a young planetary nebula. The spherically aberrated 1992 HST images, in which Bobrowsky first optically resolved the nebula, showed a compact nebula surrounding the central star. Nebular gas appeared most strongly concentrated in an ellipse with its major axis subtending 1.('') 6 from NE to SW. If this ellipse is actually a circular ring viewed obliquely, then our line of sight is inclined from the symmetry axis by 56deg . Above and below the ring of gas are two bubbles containing lower-density gas. At the tip of each bubble, there is a hole where the gas inside the bubbles has broken through and is now escaping. While images of focused jets have been obtained previously (Borkowski et al.), this is the first case where the nebular structure responsible for the focusing of an outflow can be clearly seen. The windblown appearance of the nebula is consistent with the blueshifted Si IV (1394-1403 Angstroms) and Al III (1855-1863 Angstroms) doublets observed by Parthasarathy et al. that indicated the presence of a strong stellar wind. The N V (1239-1243 Angstroms) to C IV (1548-1551 Angstroms) ratio has increased in recent years, consistent with a young nebula becoming increasingly ionized. Our new spectra reveal additional developments that show the real-time development of this young nebula. Finally, the new HST Planetary Camera images of the nebula show detailed structure indicating a much more complex object than previously known, including the presence of a companion star 0.('') from the central star.

  13. Jet-driving protostars identified from infrared observations of the Carina Nebula complex

    CERN Document Server

    Ohlendorf, Henrike; Gaczkowski, Benjamin; Ratzka, Thorsten; Grellmann, Rebekka; McLeod, Anna F

    2012-01-01

    Aims: Jets are excellent signposts for very young embedded protostars, so we want to identify jet-driving protostars as a tracer of the currently forming generation of stars in the Carina Nebula, which is one of the most massive galactic star-forming regions and which is characterised by particularly high levels of massive-star feedback on the surrounding clouds. Methods: We used archive data to construct large (> 2 deg x 2 deg) Spitzer IRAC mosaics of the Carina Nebula and performed a spatially complete search for objects with excesses in the 4.5 micron band, typical of shock-excited molecular hydrogen emission. We also identified the mid-infrared point sources that are the likely drivers of previously discovered Herbig-Haro jets and molecular hydrogen emission line objects. We combined the Spitzer photometry with our recent Herschel far-infrared data to construct the spectral energy distributions, and used the Robitaille radiative-transfer modelling tool to infer the properties of the objects. Results: The ...

  14. A deep wide-field sub-mm survey of the Carina Nebula complex

    CERN Document Server

    Preibisch, Thomas; Ohlendorf, Henrike; Pekruhl, Stephanie; Menten, Karl M; Zinnecker, Hans

    2010-01-01

    The Great Nebula in Carina is a superb location in which to study the physics of violent massive star-formation and the resulting feedback effects, including cloud dispersal and triggered star-formation. In order to reveal the cold dusty clouds in the Carina Nebula complex, we used the Large APEX Bolometer Camera LABOCA at the APEX telescope to map a 1.25 deg x 1.25 deg (= 50 x 50 pc^2) region at 870 micrometer. From a comparison to Halpha images we infer that about 6% of the 870 micrometer flux in the observed area is likely free-free emission from the HII region, while about 94% of the flux is very likely thermal dust emission. The total (dust + gas) mass of all clouds for which our map is sensitive is ~ 60 000 Msun, in good agreement with the mass of the compact clouds in this region derived from 13CO line observations. We generally find good agreement in the cloud morphology seen at 870 micrometer and the Spitzer 8 micrometer emission maps, but also identify a prominent infrared dark cloud. Finally, we co...

  15. Extended Red Objects and Stellar Wind Bow Shocks in the Carina Nebula

    CERN Document Server

    Sexton, Remington O; Smith, Nathan; Babler, Brian L; Meade, Marilyn R; Rudolph, Alexander L

    2014-01-01

    We report the results of infrared photometry on 39 extended red objects (EROs) in the Carina Nebula, observed with the Spitzer Space Telescope. Most EROs are identified by bright, extended 8.0 um emission, which ranges from 10'' to 40'' in size, but our sample also includes 4 EROs identified by extended 24 um emission. Of particular interest are nine EROs associated with late O or early B-type stars and characterized by arc-shaped morphology, suggesting dusty, stellar-wind bow shocks. These objects are preferentially oriented towards the central regions of the Carina Nebula, suggesting that these bow shocks are generally produced by the interactions of OB winds with the bulk expansion of the H II region rather than high proper motion. We identify preferred regions of mid-infrared color space occupied by our bow shock candidates, which also contain bow shock candidates in M17 and RCW 49 but are well-separated from polycyclic aromatic hydrocarbon emission or circumstellar discs. Color cuts identify an additiona...

  16. Diffuse X-ray Emission from the Carina Nebula Observed with Suzaku

    CERN Document Server

    Hamaguchi, Kenji

    2007-01-01

    A number of giant HII regions are associated with soft diffuse X-ray emission. Among these, the Carina nebula possesses the brightest soft diffuse emission. The required plasma temperature and thermal energy can be produced by collisions or termination of fast winds from main-sequence or embedded young O stars, but the extended emission is often observed from regions apart from massive stellar clusters. The origin of the X-ray emission is unknown. The XIS CCD camera onboard Suzaku has the best spectral resolution for extended soft sources so far, and is therefore capable of measuring key emission lines in the soft band. Suzaku observed the core and the eastern side of the Carina nebula (Car-D1) in 2005 Aug and 2006 June, respectively. Spectra of the south part of the core and Car-D1 similarly showed strong L-shell lines of iron ions and K-shell lines of silicon ions, while in the north of the core these lines were much weaker. Fitting the spectra with an absorbed thin-thermal plasma model showed kT~0.2, 0.6 k...

  17. A 205 μm [N II] Map of the Carina Nebula

    Science.gov (United States)

    Oberst, T. E.; Parshley, S. C.; Nikola, T.; Stacey, G. J.; Löhr, A.; Lane, A. P.; Stark, A. A.; Kamenetzky, J.

    2011-10-01

    We present the results of a ~250 arcmin2 mapping of the 205 μm [N II] fine-structure emission over the northern Carina Nebula, including the Car I and Car II H II regions. Spectra were obtained using the South Pole Imaging Fabry-Perot Interferometer (SPIFI) at the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) at the South Pole. We supplement the 205 μm data with new reductions of far-IR fine-structure spectra from the Infrared Space Observatory (ISO) Long Wavelength Spectrometer (LWS) in 63 μm [O I], 122 μm [N II], 146 μm [O I], and 158 μm [C II]; the 146 μm [O I] data include 90 raster positions which have not been previously published. Morphological comparisons are made with optical, radio continuum, and CO maps. The 122/205 line ratio is used to probe the density of the low-ionization gas, and the 158/205 line ratio is used to probe the fraction of C+ arising from photodissociation regions (PDRs). The [O I] and [C II] lines are used to construct a PDR model of Carina. When the PDR properties are compared with other sources, Carina is found to be more akin to 30 Doradus than galactic star-forming regions such as Orion, M17, or W49; this is consistent with the view of Carina as a more evolved region, where much of the parent molecular cloud has been ionized or swept away. These data constitute the first ground-based detection of the 205 μm [N II] line, and the third detection overall since those of COBE FIRAS and the Kuiper Airborne Observatory in the early 1990s.

  18. Spitzer Space Telescope observations of the Carina Nebula: The steady march of feedback-driven star formation

    CERN Document Server

    Smith, Nathan; Whitney, Barbara A; Churchwell, Ed; Babler, Brian L; Meade, Marilyn R; Bally, John; Gehrz, Robert D; Robitaille, Thomas P; Stassun, Keivan G

    2010-01-01

    We report the first results of imaging the Carina Nebula with Spitzer/IRAC, providing a catalog of point sources and YSOs based on SED fits. We discuss several aspects of the extended emission, including dust pillars that result when a clumpy molecular cloud is shredded by massive star feedback. There are few "extended green objects" (EGOs) normally taken as signposts of outflow activity, and none of the HH jets detected optically are seen as EGOs. A population of "extended red objects" tends to be found around OB stars, some with clear bow-shocks. These are dusty shocks where stellar winds collide with flows off nearby clouds. Finally, the relative distributions of O stars and subclusters of YSOs as compared to dust pillars shows that while some YSOs are located within pillars, many more stars and YSOs reside just outside pillar heads. We suggest that pillars are transient phenomena, part of a continuous outwardly propagating wave of star formation driven by massive star feedback. As pillars are destroyed, t...

  19. Precessing collimated outflows in the planetary nebula IC 4846

    CERN Document Server

    Miranda, L F; Torrelles, J M; Miranda, Luis F; Guerrero, Martin A; Torrelles, Jose M

    2000-01-01

    We present [N II] and H-alpha images and high resolution long-slit spectra of the planetary nebula IC 4846, which reveal, for the first time, its complex structure and the existence of collimated outflows. The object consists of a moderately elongated shell, two (and probably three) pairs of collimated bipolar outflows at different orientations, and an attached circular shell. One of the collimated pairs is constituted by two curved, extended filaments whose properties indicate a high velocity, bipolar precessing jet. A difference of \\~10 km/s is found between the systemic velocity of the precessing jets and the centroid velocity of the nebula, as recently report for Hu 2-1. We propose that this difference is due to orbital motion of the ejection source in a binary central star. The orbital separation and period estimates for the binary star are less than or equal to 30 AU and 100 yr, respectively. These are similar to those previously estimated for Hu 2-1, linking the central stars of both planetary nebulae ...

  20. Gaia-ESO Survey: Gas dynamics in the Carina Nebula through optical emission lines

    CERN Document Server

    Damiani, F; Magrini, L; Prisinzano, L; Mapelli, M; Micela, G; Kalari, V; Apellaniz, J Maiz; Gilmore, G; Randich, S; Alfaro, E; Flaccomio, E; Koposov, S; Klutsch, A; Lanzafame, A C; Pancino, E; Sacco, G G; Bayo, A; Carraro, G; Casey, A R; Costado, M T; Franciosini, E; Hourihane, A; Lardo, C; Lewis, J; Monaco, L; Morbidelli, L; Worley, C; Zaggia, S; Zwitter, T; Dorda, R

    2016-01-01

    We present observations from the Gaia-ESO Survey in the lines of H$\\alpha$, [N II], [S II] and He I of nebular emission in the central part of the Carina Nebula. We investigate the properties of the two already known kinematic components (approaching and receding, respectively), which account for the bulk of emission. Moreover, we investigate the features of the much less known low-intensity high-velocity (absolute RV $>$50 km/s) gas emission. We show that gas giving rise to H$\\alpha$ and He I emission is dynamically well correlated, but not identical, to gas seen through forbidden-line emission. Gas temperatures are derived from line-width ratios, and densities from [S II] doublet ratios. The spatial variation of N ionization is also studied, and found to differ between the approaching and receding components. The main result is that the bulk of the emission lines in the central part of Carina arises from several distinct shell-like expanding regions, the most evident found around $\\eta$ Car, the Trumpler 14...

  1. Suzaku Observation of Diffuse X-ray Emission from the Carina Nebula

    CERN Document Server

    Hamaguchi, K; Matsumoto, H; Tsujimoto, M; Holt, S S; Ezoe, Y; Ozawa, H; Tsuboi, Y; Soong, Y; Kitamoto, S; Sekiguchi, A; Kokubun, M; Hamaguchi, Kenji; Petre, Robert; Matsumoto, Hironori; Tsujimoto, Masahiro; Holt, Stephan S.; Ezoe, Yuichiro; Ozawa, Hideki; Tsuboi, Yohko; Soong, Yang; Kitamoto, Shunji; Sekiguchi, Akiko; Kokubun, Motohide

    2006-01-01

    We studied extended X-ray emission from the Carina Nebula taken with the Suzaku CCD camera XIS on 2005 Aug. 29. The X-ray morphology, plasma temperature and absorption to the plasma are consistent with the earlier Einstein results. The Suzaku spectra newly revealed emission lines from various species including oxygen, but not from nitrogen. This result restricts the N/O ratio significantly low, compared with evolved massive stellar winds, suggesting that the diffuse emission is originated in an old supernova remnant or a super shell produced by multiple supernova remnants. The X-ray spectra from the north and south of Eta Carinae showed distinct differences between 0.3-2 keV. The south spectrum shows strong L-shell lines of iron ions and K-shell lines of silicon ions, while the north spectrum shows them weak in intensity. This means that silicon and iron abundances are a factor of 2-4 higher in the south region than in the north region. The abundance variation may be produced by an SNR ejecta, or relate to th...

  2. Early-type massive stars in Carina Nebula within the Gaia-ESO Survey.

    Science.gov (United States)

    Berlanas, S. R.; Herrero, A.; Martins, F.; Simón-Díaz, S.; Mahy, L.; Blomme, R.; GES WG-13

    2017-03-01

    The Gaia-ESO Survey (GES) is obtaining high quality spectra of ˜ 10^5 stars in our Galaxy, providing an homogeneous and unique overview of all the main components of the Milky Way, its formation history and the evolution of young, mature and ancient Galactic populations. Our group is in charge of the early-type massive stars that define the youngest population in the survey. In this contribution, we present the results of the quantitative spectroscopic analysis of O-type stars in the Carina Nebula within the Gaia-ESO Survey. For this aim, we have used FASTWIND and CMFGEN stellar atmosphere codes, providing stellar parameters for the current sample (GES data release iDR4).

  3. OPTICAL SPECTROSCOPY OF X-RAY-SELECTED YOUNG STARS IN THE CARINA NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Vaidya, Kaushar [Physics Department, Birla Institute of Technology and Science Pilani, Pilani 333031, Rajasthan (India); Chen, Wen-Ping; Lee, Hsu-Tai [Graduate Institute of Astronomy, National Central University, 300 Zhongda Road, Zhongli 32001, Taiwan (China)

    2015-12-15

    We present low-resolution optical spectra for 29 X-ray sources identified as either massive star candidates or low-mass pre-main-sequence (PMS) star candidates in the clusters Trumpler 16 and Trumpler 14 of the Carina Nebula. Spectra of two more objects (one with an X-ray counterpart, and one with no X-ray counterpart), not originally our targets, but found close (∼3″) to two of our targets, are presented as well. Twenty early-type stars, including an O8 star, seven B1–B2 stars, two B3 stars, a B5 star, and nine emission-line stars, are identified. Eleven T Tauri stars, including eight classical T Tauri stars (CTTSs) and three weak-lined T Tauri stars, are identified. The early-type stars in our sample are more reddened compared to the previously known OB stars of the region. The Chandra hardness ratios of our T Tauri stars are found to be consistent with the Chandra hardness ratios of T Tauri stars of the Orion Nebula Cluster. Most early-type stars are found to be nonvariable in X-ray emission, except the B2 star J104518.81–594217.9, the B3 star J104507.84–594134.0, and the Ae star J104424.76–594555.0, which are possible X-ray variables. J104452.20–594155.1, a CTTS, is among the brightest and the hardest X-ray sources in our sample, appears to be a variable, and shows a strong X-ray flare. The mean optical and near-infrared photometric variability in the V and K{sub s} bands, of all sources, is found to be ∼0.04 and 0.05 mag, respectively. The T Tauri stars show significantly larger mean variation, ∼0.1 mag, in the K{sub s} band. The addition of one O star and seven B1–B2 stars reported here contributes to an 11% increase of the known OB population in the observed field. The 11 T Tauri stars are the first ever confirmed low-mass PMS stars in the Carina Nebula region.

  4. Gaia-ESO Survey: Gas dynamics in the Carina nebula through optical emission lines

    Science.gov (United States)

    Damiani, F.; Bonito, R.; Magrini, L.; Prisinzano, L.; Mapelli, M.; Micela, G.; Kalari, V.; Maíz Apellániz, J.; Gilmore, G.; Randich, S.; Alfaro, E.; Flaccomio, E.; Koposov, S.; Klutsch, A.; Lanzafame, A. C.; Pancino, E.; Sacco, G. G.; Bayo, A.; Carraro, G.; Casey, A. R.; Costado, M. T.; Franciosini, E.; Hourihane, A.; Lardo, C.; Lewis, J.; Monaco, L.; Morbidelli, L.; Worley, C.; Zaggia, S.; Zwitter, T.; Dorda, R.

    2016-06-01

    Aims: We present observations from the Gaia-ESO Survey in the lines of Hα, [N II], [S II], and He I of nebular emission in the central part of the Carina nebula. Methods: We investigate the properties of the two already known kinematic components (approaching and receding), which account for the bulk of emission. Moreover, we investigate the features of the much less known low-intensity high-velocity (absolute RV >50 km s-1) gas emission. Results: We show that gas giving rise to Hα and He I emission is dynamically well correlated with but not identical to gas seen through forbidden-line emission. Gas temperatures are derived from line-width ratios, and densities from [S II] doublet ratios. The spatial variation of N ionization is also studied, and found to differ between the approaching and receding components. The main result is that the bulk of the emission lines in the central part of Carina arise from several distinct shell-like expanding regions, the most evident found around η Car, the Trumpler 14 core, and the star WR25. These "shells" are non-spherical and show distortions probably caused by collisions with other shells or colder, higher-density gas. Some of them are also partially obscured by foreground dust lanes, while very little dust is found in their interior. Preferential directions, parallel to the dark dust lanes, are found in the shell geometries and physical properties, probably related to strong density gradients in the studied region. We also find evidence that the ionizing flux emerging from η Car and the surrounding Homunculus nebula varies with polar angle. The high-velocity components in the wings of Hα are found to arise from expanding dust reflecting the η Car spectrum. Based on observations collected with the FLAMES spectrograph at VLT/UT2 telescope (Paranal Observatory, ESO, Chile), for the Gaia-ESO Large Public Survey (program 188.B-3002).Full Tables 1-3 are only available at the CDS via anonymous ftp to http

  5. The Clump Mass Function of the Dense Clouds in the Carina Nebula Complex

    CERN Document Server

    Pekruhl, Stephanie; Schuller, Frederic; Menten, Karl

    2012-01-01

    We want to characterize the properties of the cold dust clumps in the Carina Nebula Complex (CNC), which shows a very high level of massive star feedback. We derive the Clump Mass Function (ClMF), explore the reliability of different clump extraction algorithms, and investigate the influence of the temperatures within the clouds on the resulting shape of the ClMF. We analyze a 1.25x1.25 deg^2 wide-field sub-mm map obtained with LABOCA (APEX), which provides the first spatially complete survey of the clouds in the CNC. We use the three clump-finding algorithms CLUMPFIND (CF), GAUSSCLUMPS (GC) and SExtractor (SE) to identify individual clumps and determine their total fluxes. In addition to assuming a common `typical' temperature for all clouds, we also employ an empirical relation between cloud column densities and temperature to determine an estimate of the individual clump temperatures, and use this to determine individual clump masses. While the ClMF based on the CF extraction is very well described by a po...

  6. Suzaku Observation of Diffuse X-ray Emission from the Carina Nebula

    Science.gov (United States)

    Hamaguchi, Kenji; Petre, Robert; Matsumoti, Hironori; Tsujimoto, Masahiro; Holt, Stephan S.; Ezoe, Yuichiro; Ozawa, Hideki; Tsuboi, Yohko; Soong, Yang; Kitamoto, Shunji; Sekiguchi, Akiko; Kokubun, Motohide

    2007-01-01

    We studied extended X-ray emission from the Carina Nebula taken with the Suzaku CCD camera XIS on 2005 Aug. 29. The X-ray morphology, plasma temperature and absorption to the plasma are consistent with the earlier Einstein results. The Suzaku spectra newly revealed emission lines from various spices including oxygen, but not from nitrogen. This result restricts the N/O ratio significantly low, compared with evolved massive stellar winds, suggesting that the diffuse emission is originated in an old supernova remnant or a super shell produced by multiple supernova remnants. The X-ray spectra from the north and south of eta Car showed distinct differences between 0.3-2 keV. The south spectrum shows strong L-shell lines of iron ions and K-shell lines of silicon ions, while the north spectrum shows them weak in intensity. This means that silicon and iron abundances are a factor of 2-4 higher in the south region than in the north region. The abundance variation may be produced by an SNR ejecta, or relate to the dust formation around the star forming core.

  7. The clump mass function of the dense clouds in the Carina nebula complex

    Science.gov (United States)

    Pekruhl, S.; Preibisch, T.; Schuller, F.; Menten, K.

    2013-02-01

    Context. The question how the initial conditions in a star-forming region affect the resulting mass function of the forming stars is one of the most fundamental open topics in star formation theory. Aims: We want to characterize the properties of the cold dust clumps in the Carina nebula complex, which is one of the most massive star forming regions in our Galaxy and shows a very high level of massive star feedback. We derive the clump mass function (ClMF), explore the reliability of different clump extraction algorithms, and investigate the influence of the temperatures within the clouds on the resulting shape of the ClMF. Methods: We analyze a 1.25° × 1.25° wide-field submillimeter map obtained with LABOCA at the APEX telescope, which provides the first spatially complete survey of the clouds in the Carina nebula complex. We use the three clump-finding algorithms CLUMPFIND, GAUSSCLUMPS and SExtractor to identify individual clumps and determine their total fluxes. In addition to assuming a common "typical" temperature for all clouds, we also employ an empirical relation between cloud column densities and temperature to determine an estimate of the individual clump temperatures, and use this to determine individual clump masses. Results: We find that the ClMFs resulting from the different extraction methods show considerable differences in their shape. While the ClMF based on the CLUMPFIND extraction is very well described by a power-law (for clump masses well above the completeness limit), the ClMFs based on the extractions with GAUSSCLUMPS and SExtractor are better represented by a log-normal distribution. We also find that the use of individual clump temperatures leads to a shallower ClMF slope than the (often used) assumption of a common temperature (e.g. 20 K) of all clumps. Conclusions: The power-law of dN/dM ∝ M-1.95 we find for the CLUMPFIND sample is in good agreement with ClMF slopes found in previous studies of the ClMFs of other regions. The

  8. Near-Infrared properties of the X-ray emitting young stellar objects in the Carina Nebula

    CERN Document Server

    Preibisch, Thomas; Irwin, Mike; Lewis, James R; King, Robert R; McCaughrean, Mark J; Zinnecker, Hans; Townsley, Leisa; Broos, Patrick

    2011-01-01

    Abbreviated Abstract: The near-infrared study of the Carina Nebula in this paper builds on the results of the Chandra Carina Complex Project (CCCP), that detected 14368 X-ray sources in the 1.4 square-degree survey region, an automatic source classification study that classified 10714 of these as very likely young stars in Carina, and an analysis of their clustering properties. We used HAWK-I at the ESO VLT to conduct a very deep near-IR survey with sub-arcsecond angular resolution, covering about 1280 square-arcminutes. The HAWK-I images reveal more than 600000 individual infrared sources, whereby objects as faint as J ~ 23, H ~ 22, and Ks ~ 21 are detected at S/N >= 3. While less than half of the Chandra X-ray sources have counterparts in the 2MASS catalog, the ~5 mag deeper HAWK-I data reveal infrared counterparts to 6636 (= 88.8%) of the 7472 Chandra X-ray sources in the HAWK-I field. We analyze near-infrared color-color and color-magnitude diagrams to derive information about the extinctions, infrared ex...

  9. Herschel far-infrared observations of the Carina Nebula complex II: The embedded young stellar and protostellar population

    CERN Document Server

    Gaczkowski, Benjamin; Ratzka, Thorsten; Roccatagliata, Veronica; Ohlendorf, Henrike; Zinnecker, Hans

    2012-01-01

    The Carina Nebula represents one of the largest and most active star forming regions known in our Galaxy with numerous very massive stars.Our recently obtained Herschel PACS & SPIRE far-infrared maps cover the full area (about 8.7 deg^2) of the Carina Nebula complex and reveal the population of deeply embedded young stellar objects, most of which are not yet visible in the mid- or near-infrared.We study the properties of the 642 objects that are independently detected as point-like sources in at least two of the five Herschel bands.For those objects that can be identified with apparently single Spitzer counterparts, we use radiative transfer models to derive information about the basic stellar and circumstellar parameters.We find that about 75% of the Herschel-detected YSOs are Class 0 protostars.The luminosities of the Herschel-detected YSOs with SED fits are restricted to values of <=5400 Lsun, their masses (estimated from the radiative transfer modeling) range from about 1 Msun to 10 Msun.Taking the...

  10. Outflows, dusty cores, and a burst of star formation in the North America and Pelican nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Bally, John [Department of Astrophysical and Planetary Sciences, University of Colorado, UCB 389, Boulder, CO 80309 (United States); Ginsburg, Adam [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Munchen (Germany); Probst, Ron [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Reipurth, Bo [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii at Manoa, 640 North A' ohoku Place, Hilo, HI 96720 (United States); Shirley, Yancy L. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Stringfellow, Guy S., E-mail: John.Bally@colorado.edu, E-mail: aginsburg@eso.org, E-mail: probst@noao.edu, E-mail: reipurth@ifa.hawaii.edu, E-mail: yshirley@as.arizona.edu, E-mail: Guy.Stringfellow@colorado.edu [Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 80309 (United States)

    2014-12-01

    We present observations of near-infrared 2.12 μm molecular hydrogen outflows emerging from 1.1 mm dust continuum clumps in the North America and Pelican Nebula (NAP) complex selected from the Bolocam Galactic Plane Survey (BGPS). Hundreds of individual shocks powered by over 50 outflows from young stars are identified, indicating that the dusty molecular clumps surrounding the NGC 7000/IC 5070/W80 H II region are among the most active sites of ongoing star formation in the solar vicinity. A spectacular X-shaped outflow, MHO 3400, emerges from a young star system embedded in a dense clump more than a parsec from the ionization front associated with the Pelican Nebula (IC 5070). Suspected to be a binary, the source drives a pair of outflows with orientations differing by 80°. Each flow exhibits S-shaped symmetry and multiple shocks indicating a pulsed and precessing jet. The 'Gulf of Mexico', located south of the North America Nebula (NGC 7000), contains a dense cluster of molecular hydrogen objects (MHOs), Herbig-Haro (HH) objects, and over 300 young stellar objects (YSOs), indicating a recent burst of star formation. The largest outflow detected thus far in the North America and Pelican Nebula complex, the 1.6 parsec long MHO 3417 flow, emerges from a 500 M {sub ☉} BGPS clump and may be powered by a forming massive star. Several prominent outflows such as MHO 3427 appear to be powered by highly embedded YSOs only visible at λ > 70 μm. An 'activity index' formed by dividing the number of shocks by the mass of the cloud containing their source stars is used to estimate the relative evolutionary states of Bolocam clumps. Outflows can be used as indicators of the evolutionary state of clumps detected in millimeter and submillimeter dust continuum surveys.

  11. The Nature and Frequency of Outflows from Stars in the Central Orion Nebula Cluster

    CERN Document Server

    O'Dell, C R; Henney, W J; Peimbert, M; Garcia-Diaz, Ma T; Rubin, Robert H

    2015-01-01

    Recent Hubble Space Telescope images have allowed the determination with unprecedented accuracy of motions and changes of shocks within the inner Orion Nebula. These originate from collimated outflows from very young stars, some within the ionized portion of the nebula and others within the host molecular cloud. We have doubled the number of Herbig-Haro objects known within the inner Orion Nebula. We find that the best-known Herbig-Haro shocks originate from a relatively few stars, with the optically visible X-ray source COUP 666 driving many of them. While some isolated shocks are driven by single collimated outflows, many groups of shocks are the result of a single stellar source having jets oriented in multiple directions at similar times. This explains the feature that shocks aligned in opposite directions in the plane of the sky are usually blue shifted because the redshifted outflows pass into the optically thick Photon Dominated Region behind the nebula. There are two regions from which optical outflow...

  12. Multiple outflows in the bipolar planetary nebula M1-16: A molecular line study

    NARCIS (Netherlands)

    Sahai, Raghvendra; Wootten, Alwyn; Schwarz, Hugo E.; Wild, W.

    1994-01-01

    Extensive observations of the molecular gas in the young, compact planetary nebula M1-16 have been made, using the Swedish-ESO-Submillimeter Telescope. A map of the CO J = 2-1 emission shows that the molecular envelope contains both a slow and a fast outflow with expansion velocities of 19 km/s and

  13. THE NATURE AND FREQUENCY OF OUTFLOWS FROM STARS IN THE CENTRAL ORION NEBULA CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    O’Dell, C. R. [Department of Physics and Astronomy, Vanderbilt University, Box 1807-B, Nashville, TN 37235 (United States); Ferland, G. J. [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Henney, W. J. [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apartado Postal 3-72, 58090 Morelia, Michoacán, México (Mexico); Peimbert, M. [Instituto de Astronomia, Universidad Nacional Autónoma de México, Apdo, Postal 70-264, 04510 México D. F., México (Mexico); García-Díaz, Ma. T. [Instituto de Astronomia, Universidad Nacional Autónoma de México, Km 103 Carretera Tijuana-Ensenada, 22860 Ensenada, B.C., México (Mexico); Rubin, Robert H., E-mail: cr.odell@vanderbilt.edu [NASA/Ames Research Center, Moffett Field, CA 94035-0001 (United States)

    2015-10-15

    Recent Hubble Space Telescope images have allowed the determination with unprecedented accuracy of motions and changes of shocks within the inner Orion Nebula. These originate from collimated outflows from very young stars, some within the ionized portion of the nebula and others within the host molecular cloud. We have doubled the number of Herbig–Haro objects known within the inner Orion Nebula. We find that the best-known Herbig–Haro shocks originate from relatively few stars, with the optically visible X-ray source COUP 666 driving many of them. While some isolated shocks are driven by single collimated outflows, many groups of shocks are the result of a single stellar source having jets oriented in multiple directions at similar times. This explains the feature that shocks aligned in opposite directions in the plane of the sky are usually blueshifted because the redshifted outflows pass into the optically thick photon-dominated region behind the nebula. There are two regions from which optical outflows originate for which there are no candidate sources in the SIMBAD database.

  14. Submillimeter spectroscopy of the Carina Nebula: Observations, operations and upgrades of the South Pole Imaging Fabry-Perot Interferometer

    Science.gov (United States)

    Oberst, Thomas Edward

    2009-06-01

    We present the results of a ~ 250 arcmin 2 mapping of the 205 μm [NII] fine- structure line emission over the northern Carina Nebula, including the Car I and Car II HII regions. Spectra were obtained using the South Pole Imaging Fabry-Perot Interferometer (SPIFI) at the Antarctic Telescope and Remote Observatory (AST/RO) at South Pole. New upgrades and modifications to the SPIFI instrument are discussed, and full details of SPIFI-AST/RO integration and calibration are provided. At the time of these observations, SPIFI had a spectral resolving power of ~ 4250, a FWHM beam size of ~ 54'', and a noise equivalent power (NEP) referred to the front end of the receiver of ~ 2.5 × 10 -15 W Hz -1/2 (~ 1.4 times the background limit). These data constitute the first ground-based detection of the 205 μm [NII] line, and only the third detection overall since those of the Cosmic Background Explorer (COBE) Far Infrared Absolute Spectrophotometer (FIRAS) and the Kuiper Airborne Observatory (KAO) in the early 1990s. We supplement the 205 μm data with new reductions of far-infrared fine- structure spectra from the Infrared Space Observatory (ISO) in 63 μm [OI], 122 m [NII], 146 μm [OI], and 158 μm [CII]; the 146 μm [OI] data include 90 raster positions which have not been previously published. Morphological comparisons are made with optical, radio continuum and CO maps. The 122/205 [NII] line ratio is used to probe the density of the low-ionization gas, and the 158/205 [CII]/[NII] line ratio is used to probe the fraction of C + arising from photodissociation regions (PDRs). The [OI] and [CII] lines are used to construct a PDR model of Carina following Kaufman et al. (1999). When the PDR properties are compared with other sources, Carina is found to be more akin to 30 Doradus than galactic star-forming regions such as Orion, M17, or W49. This is consistent with the view of Carina as a more evolved region, where much of the parent molecular cloud has been ionized or swept

  15. Outflows, Dusty Cores, and a Burst of Star Formation in the North America and Pelican Nebulae

    CERN Document Server

    Bally, John; Probst, Ron; Reipurth, Bo; Shirley, Yancy L; Stringfellow, Guy S

    2014-01-01

    We present observations of near-infrared 2.12 micro-meter molecular hydrogen outflows emerging from 1.1 mm dust continuum clumps in the North America and Pelican Nebula (NAP) complex selected from the Bolocam Galactic Plane Survey (BGPS). Hundreds of individual shocks powered by over 50 outflows from young stars are identified, indicating that the dusty molecular clumps surrounding the NGC 7000 / IC 5070 / W80 HII region are among the most active sites of on-going star formation in the Solar vicinity. A spectacular X-shaped outflow, MHO 3400, emerges from a young star system embedded in a dense clump more than a parsec from the ionization front associated with the Pelican Nebula (IC 5070). Suspected to be a binary, the source drives a pair of outflows with orientations differing by 80 degrees. Each flow exhibits S-shaped symmetry and multiple shocks indicating a pulsed and precessing jet. The `Gulf of Mexico' located south of the North America Nebula (NGC 7000), contains a dense cluster of molecular hydrogen ...

  16. The Spectral Temperature of Optically Thick Outflows with Application to Light Echo Spectra from $\\eta$~Carinae's Giant Eruption

    CERN Document Server

    Owocki, Stanley P

    2016-01-01

    The detection by Rest et al. (2012) of light echoes from $\\eta$ Carinae has provided important new observational constraints on the nature of its 1840's era giant eruption. Spectra of the echoes suggest a relatively cool spectral temperature of about 5500K, lower than the lower limit of about 7000K suggested in the optically thick wind outflow analysis of Davidson (1987). This has lead to a debate about the viability of this steady wind model relative to alternative, explosive scenarios. Here we present an updated analysis of the wind outflow model using newer low-temperature opacity tabulations and accounting for the stronger mass loss implied by the $>$10 Msun mass now inferred for the Homunculus. A major conclusion is that, because of the sharp drop in opacity due to free electron recombination for $T<$6500K, a low temperature of about 5000K is compatible with, and indeed expected from, a wind with the extreme mass loss inferred for the eruption. Within a spherical gray model in radiative equilibrium, w...

  17. MULTIPLE FAST MOLECULAR OUTFLOWS IN THE PRE-PLANETARY NEBULA CRL 618

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chin-Fei; Huang, Po-Sheng [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China); Sahai, Raghvendra [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Sánchez Contreras, Carmen [Astrobiology Center (CSIC-INTA), ESAC Campus, E-28691 Villanueva de la Canada, Madrid (Spain); Tay, Jeremy Jian Hao [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)

    2013-11-01

    CRL 618 is a well-studied pre-planetary nebula. It has multiple highly collimated optical lobes, fast molecular outflows along the optical lobes, and an extended molecular envelope that consists of a dense torus in the equator and a tenuous round halo. Here we present our observations of this source in CO J = 3-2 and HCN J = 4-3 obtained with the Submillimeter Array at up to ∼0.''3 resolutions. We spatially resolve the fast molecular outflow region previously detected in CO near the central star and find it to be composed of multiple outflows that have similar dynamical ages and are oriented along the different optical lobes. We also detect fast molecular outflows further away from the central star near the tips of the extended optical lobes and a pair of equatorial outflows inside the dense torus. We find that two episodes of bullet ejections in different directions are needed, one producing the fast molecular outflows near the central star and one producing the fast molecular outflows near the tips of the extended optical lobes. One possibility to launch these bullets is a magneto-rotational explosion of the stellar envelope.

  18. The VISTA Carina Nebula Survey. II. Spatial distribution of the infrared-excess-selected young stellar population

    Science.gov (United States)

    Zeidler, P.; Preibisch, T.; Ratzka, T.; Roccatagliata, V.; Petr-Gotzens, M. G.

    2016-01-01

    We performed a deep wide-field (6.76 sq. deg) near-infrared survey with the VISTA telescope that covers the entire extent of the Carina nebula complex (CNC). The point-source catalog created from these data contains around four million individual objects down to masses of 0.1 M⊙. We present a statistical study of the large-scale spatial distribution and an investigation of the clustering properties of infrared-excesses objects, which are used to trace disk-bearing young stellar objects (YSOs). A selection based on a near-infrared (J-H) versus (H-Ks) color-color diagram shows an almost uniform distribution over the entire observed area. We interpret this as a result of the very high degree of background contamination that arises from the Carina Nebula's location close to the Galactic plane. Complementing the VISTA near-infrared catalog with Spitzer IRAC mid-infrared photometry improves the situation of the background contamination considerably. We find that a (J-H) versus (Ks- [4.5]) color-color diagram is well suited to tracing the population of YSO-candidates (cYSOs) by their infrared excess. We identify 8781 sources with strong infrared excess, which we consider as cYSOs. This sample is used to investigate the spatial distribution of the cYSOs with a nearest-neighbor analysis. The surface density distribution of cYSOs agrees well with the shape of the clouds as seen in our Herschel far-infrared survey. The strong decline in the surface density of excess sources outside the area of the clouds supports the hypothesis that our excess-selected sample consists predominantly of cYSOs with a low level of background contamination. This analysis allows us to identify 14 groups of cYSOs outside the central area.Our results suggest that the total population of cYSOs in the CNC comprises about 164 000 objects, with a substantial fraction (~35%) located in the northern, still not well studied parts. Our cluster analysis suggests that roughly half of the cYSOs constitute a

  19. The spectral temperature of optically thick outflows with application to light echo spectra from η Carinae's giant eruption

    Science.gov (United States)

    Owocki, Stanley P.; Shaviv, Nir J.

    2016-10-01

    The detection by Rest et al. of light echoes from η Carinae has provided important new observational constraints on the nature of its 1840s era giant eruption. Spectra of the echoes suggest a relatively cool spectral temperature of about 5500 K, lower than the lower limit of about 7000 K suggested in the optically thick wind-outflow analysis of Davidson. This has led to a debate about the viability of this steady wind model relative to alternative, explosive scenarios. Here we present an updated analysis of the wind-outflow model using newer low-temperature opacity tabulations and accounting for the stronger mass-loss implied by the >10 M⊙ mass now inferred for the Homunculus. A major conclusion is that, because of the sharp drop in opacity due to recombination loss of free electrons for T < 6500 K, a low temperature of about 5000 K is compatible with, and indeed expected from, a wind with the extreme mass-loss inferred for the eruption. Within a spherical grey model in radiative equilibrium, we derive spectral energy distributions for various assumptions for the opacity variation of the wind, providing a basis for comparisons with observed light echo spectra. The scaling results here are also potentially relevant for other highly optically thick outflows, including those from classical novae, giant eruptions of luminous blue variables and supernovae Type IIn precursors. A broader issue therefore remains whether the complex, variable features observed from such eruptions are better understood in terms of a steady or explosive paradigm, or perhaps a balance of these idealizations.

  20. A second post-AGB nebula that contains gas in rotation and in expansion: ALMA maps of IW Carinae

    Science.gov (United States)

    Bujarrabal, V.; Castro-Carrizo, A.; Alcolea, J.; Van Winckel, H.; Sánchez Contreras, C.; Santander-García, M.

    2017-01-01

    Aims: We aim to study the presence of both rotation and expansion in post-AGB nebulae, in particular around IW Car, a binary post-AGB star that was suspected to be surrounded by a Keplerian disk. Methods: We obtained high-quality ALMA observations of 12CO and 13CO J = 3-2 lines in IW Car. The maps were analyzed by means of a simplified model of CO emission, based on those used for similar objects. Results: Our observations clearly show the presence of gas components in rotation, in an equatorial disk, and expansion, which shows an hourglass-like structure with a symmetry axis perpendicular to the rotation plane and is probably formed of material extracted from the disk. Our modeling can reproduce the observations and shows moderate uncertainties. The rotation velocity corresponds to a central stellar mass of approximately 1 M⊙. We also derive the total mass of the molecule-rich nebula, found to be of 4 × 10-3M⊙; the outflow is approximately eight times less massive than the disk. From the kinematical age of the outflow and the mass values derived for both components, we infer a (future) lifetime of the disk of approximately 5000-10 000 yr.

  1. The Carina Nebula and Gum 31 molecular complex: I. Molecular gas distribution, column densities and dust temperatures

    CERN Document Server

    Rebolledo, David; Green, Anne; Braiding, Catherine; Molinari, Sergio; Wong, Graeme; Blackwell, Rebecca; Elia, Davide; Schisano, Eugenio

    2015-01-01

    We report high resolution observations of the $^{12}$CO$(1\\rightarrow0)$ and $^{13}$CO$(1\\rightarrow0)$ molecular lines in the Carina Nebula and the Gum 31 region obtained with the 22-m Mopra telescope as part of the The Mopra Southern Galactic Plane CO Survey. We cover 8 deg$^2$ from $l = 285^{\\circ}$ to 290$^{\\circ}$, and from $b = -1.5^{\\circ}$ to +0.5$^{\\circ}$. The molecular gas column density distributions from both tracers have a similar range of values. By fitting a grey-body function to the observed infrared spectral energy distribution from Herschel maps, we derive gas column densities and dust temperatures. The gas column density has values in the range from $6.3\\times\\ 10^{20}$ to $1.4\\times 10^{23}$ cm$^{-2}$, while the dust temperature has values in the range from 17 to 43 K. The gas column density derived from the dust emission is approximately described by a log-normal function for a limited range of column densities. A high-column density tail is clearly evident for the gas column density dis...

  2. Mass accretion rates from multi-band photometry in the Carina Nebula: the case of Trumpler 14

    CERN Document Server

    Beccari, G; Panagia, N; Valenti, E; Carraro, G; Romaniello, M; Zoccali, M; Weidner, C

    2014-01-01

    We present a study of the mass accretion rates of pre-Main Sequence (PMS) stars in the cluster Trumpler 14 (Tr14) in the Carina Nebula. Using optical multi-band photometry we were able to identify 356 PMS stars showing H-alpha excess emission with equivalent width EW(H-alpha)>20\\AA. We interpret this observational feature as indication that these objects are still actively accreting gas from their circumstellar medium. From a comparison of the HR diagram with PMS evolutionary models we derive ages and masses of the PMS stars. We find that most of the PMS objects are younger than 10 Myr with a median age of ~3 Myr. Surprisingly, we also find that ~20% of the mass accreting objects are older than 10 Myr. For each PMS star in Trumpler 14 we determine the mass accretion rate ($\\dot{M}_{acc}$) and discuss its dependence on mass and age. We finally combine the optical photometry with near-IR observations to build the spectral energy distribution (SED) for each PMS star in Tr14. The analysis of the SEDs suggests the...

  3. Near-infrared integral field spectroscopy of the Homunculus nebula around Eta Carinae using Gemini/CIRPASS

    CERN Document Server

    Teodoro, M; Sharp, R G; Groh, J H; Barbosa, C L

    2008-01-01

    This work presents the first integral field spectroscopy of the Homunculus nebula around Eta Carinae in the near-infrared spectral region (J band). We confirmed the presence of a hole on the polar region of each lobe, as indicated by previous near-IR long-slit spectra and mid-IR images. The holes can be described as a cylinder of height (i.e. the thickness of the lobe) and diameter of 6.5 and 6.0x10^{16} cm, respectively. We also mapped the blue-shifted component of He I 10830 seen towards the NW lobe. Contrary to previous works, we suggested that this blue-shifted component is not related to the Paddle but it is indeed in the equatorial disc. We confirmed the claim of Smith (2005) and showed that the spatial extent of the Little Homunculus matches remarkably well the radio continuum emission at 3 cm, indicating that the Little Homunculus can be regarded as a small HII region. Therefore, we used the optically-thin 1.3 mm radio flux to derive a lower limit for the number of Lyman-continuum photons of the centr...

  4. Herschel far-infrared observations of the Carina Nebula Complex. - III: Detailed cloud structure and feedback effects

    CERN Document Server

    Roccatagliata, Veronica; Ratzka, Thorsten; Gaczkowski, Benjamin

    2013-01-01

    The Carina Nebula complex (CNC) represents one of the most massive star-forming regions in our Galaxy and shows strong feedback from the high massive stars. We use our Herschel FIR observations to study the properties of the clouds over the entire area of the CNC. The good angular resolution of the Herschel maps corresponds to physical scales of 0.1 - 0.4 pc, and allows us to analyze the small-scale structures of the clouds. The full extent of the CNC was mapped with PACS and SPIRE from 70 to 500 micron. We determine temperatures and column densities at each point in this maps by modeling the observed FIR SEDs. We also derive a map showing the strength of the UV field. We investigate the relation between the cloud properties and the spatial distribution of the high-mass stars, and compute total cloud masses for different density thresholds. Our Herschel maps resolve, for the first time, the small-scale structure of the dense clouds. Several particularly interesting regions, including the prominent pillars sou...

  5. The VISTA Carina Nebula Survey II. Spatial distribution of the infrared-excess-selected young stellar population

    CERN Document Server

    Zeidler, Peter; Ratzka, Thorsten; Roccatagliata, Veronica; Petr-Gotzens, Monika G

    2016-01-01

    We performed a deep wide-field (6.76 deg^2) near-infrared survey with the VISTA telescope that covers the entire extent of the Carina nebula complex (CNC). The point-source catalog created from these data contains around four million individual objects down to masses of 0.1 M_sun. We present a statistical study of the large-scale spatial distribution and an investigation of the clustering properties of infrared-excesses objects, which are used to trace disk-bearing young stellar objects (YSOs). We find that a (J - H) versus (Ks - [4.5]) color-color diagram is well suited to tracing the population of YSO-candidates (cYSOs) by their infrared excess. We identify 8781 sources with strong infrared excess, which we consider as cYSOs. This sample is used to investigate the spatial distribution of the cYSOs with a nearest-neighbor analysis. The surface density distribution of cYSOs agrees well with the shape of the clouds as seen in our Herschel far-infrared survey. The strong decline in the surface density of excess...

  6. The triple-shell structure and collimated outflows of the planetary nebula NGC 6891

    CERN Document Server

    Guerrero, M; Manchado, A; Vázquez, R A

    1999-01-01

    Narrow-band H$\\alpha$ and [N {\\sc ii}] images and high-dispersion spatially-resolved echelle spectroscopy of the planetary nebula NGC 6891 are presented. These observations show a great wealth of structures. The bright central nebula is surrounded by an attached shell and a detached outer halo. Both the inner and intermediate shells can be described as ellipsoids with similar major to minor axial ratios, but different spatial orientations. The kinematical ages of the intermediate shell and halo are 4,800 and 28,000 years, respectively. The inter-shell time lapse is in good agreement with the evolutionary inter-pulse time lapse. A highly collimated outflow is observed to protrude from the tips of the major axis of the inner nebula and impact on the outer edge of the intermediate shell. Kinematics and excitation of this outflow provide conclusive evidence that it is deflected during the interaction with the outer edge of the intermediate shell. At the same time, both the kinematics and the morphology of the int...

  7. The peculiar isolated neutron star in the Carina Nebula - Deep XMM-Newton and ESO-VLT observations of 2XMM J104608.7-594306

    CERN Document Server

    Pires, Adriana Mancini; Turolla, Roberto; Schwope, Axel; Pilia, Maura; Treves, Aldo; Popov, Sergei B; Janot-Pacheco, Eduardo

    2012-01-01

    While fewer in number relative to the dominant rotation-powered radio pulsar population, peculiar classes of isolated neutron stars (INSs) -- which include magnetars, the ROSAT-discovered "Magnificent Seven" (M7), rotating radio transients (RRATs) and central compact objects in supernova remnants (CCOs) -- represent a key element to understand the neutron star phenomenology. We report here on the results of an observational campaign aiming at studying the properties of the source 2XMM J104608.7-594306. Its evolutionary state is investigated by means of deep dedicated observations obtained with XMM-Newton, the ESO Very Large Telescope as well as on publicly available gamma-ray data from the Fermi and AGILE missions. The observations confirm previous expectations and further reveal a unique object. The source, likely within the Carina Nebula, shows a soft spectrum with absorption features and no magnetospheric emission. The optical counterpart is fainter than V=27 and no gamma-ray emission is significantly dete...

  8. The fast, massive outflow of the pre-planetary nebula IRAS 19374+2356

    Science.gov (United States)

    Sánchez Contreras, C.; Martin, S.; Sahai, R.

    2013-05-01

    At some point in the late-AGB stage, a process (or processes) becomes operative that accelerates and imposes bipolarity upon the slow, spherical AGB winds. What produces bipolarity in these objects and at what stage does bipolarity manifest itself are key questions that remain yet poorly understood. We present CO (115 & 230 GHz) emission maps of IRAS19374+2359, an extreme pre-PN with an unparalleledly massive, fast molecular outflow discovered in our OVRO Post-AGB CO 1-0 emission Survey (referred to as OPACOS; Sánchez Contreras & Sahai 2012, ApJS, 203, 16). We present sub-arcsecond resolution ^{(12,13)}CO 2-1 and 1.3 mm-continuum interferometric maps recently obtained with the Submillimeter Array (SMA) together with our discovery ˜8s-resolution ^{(12,13)}CO 1-0 OVRO data. The prominent ˜300 km s^{-1}-broad wings and the lack of an intense, low-velocity CO line core in IRAS 19374 indicate that most or all of the molecular gas participates in the high-velocity flow. From our CO data, we estimate a total mass in the molecular outflow of ˜ 1 msun and an unprecedentedly large value for the linear momemtum carried of ≥ 45 msun km s^{-1}. Our SMA maps show CO emission arising from a ˜3s×2s hourglass-shaped molecular flow aligned with the optical lobes; a linear velocity gradient along the lobes as well as equatorial expansion at the nebula waist are found. The spatio-kinematic structure of this object is in support of a jet-envelope entrainment scenario in which a substantial amount of directed momentum is transferred to large parts of the dense AGB wind by interaction with fast, collimated post-AGB jets.

  9. MOLECULES IN {eta} CARINAE

    Energy Technology Data Exchange (ETDEWEB)

    Loinard, Laurent; Menten, Karl M.; Guesten, Rolf [Max-Planck Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Zapata, Luis A.; Rodriguez, Luis F. [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 3-72, 58090 Morelia, Michoacan (Mexico)

    2012-04-10

    We report the detection toward {eta} Carinae of six new molecules, CO, CN, HCO{sup +}, HCN, HNC, and N{sub 2}H{sup +}, and of two of their less abundant isotopic counterparts, {sup 13}CO and H{sup 13}CN. The line profiles are moderately broad ({approx}100 km s{sup -1}), indicating that the emission originates in the dense, possibly clumpy, central arcsecond of the Homunculus Nebula. Contrary to previous claims, CO and HCO{sup +} do not appear to be underabundant in {eta} Carinae. On the other hand, molecules containing nitrogen or the {sup 13}C isotope of carbon are overabundant by about one order of magnitude. This demonstrates that, together with the dust responsible for the dimming of {eta} Carinae following the Great Eruption, the molecules detected here must have formed in situ out of CNO-processed stellar material.

  10. Molecules in \\eta\\ Carinae

    CERN Document Server

    Loinard, Laurent; Guesten, Rolf; Zapata, Luis A; Rodriguez, Luis F

    2012-01-01

    We report the detection toward \\eta\\ Carinae of six new molecules, CO, CN, HCO+, HCN, HNC, and N2H+, and of two of their less abundant isotopic counterparts, 13CO and H13CN. The line profiles are moderately broad (about 100 km /s) indicating that the emission originates in the dense, possibly clumpy, central arcsecond of the Homunculus Nebula. Contrary to previous claims, CO and HCO+ do not appear to be under-abundant in \\eta\\ Carinae. On the other hand, molecules containing nitrogen or the 13C isotope of carbon are overabundant by about one order of magnitude. This demonstrates that, together with the dust responsible for the dimming of eta Carinae following the Great Eruption, the molecules detected here must have formed in situ out of CNO-processed stellar material.

  11. A Massive Bipolar Outflow and a Dusty Torus with Large Grains in the Preplanetary Nebula IRAS 22036+5306

    Science.gov (United States)

    Sahai, Raghvendra; Young, K.; Patel, N. A.; Sanchez Contreras, C.; Morris, M.

    2006-01-01

    We report high angular resolution (approx.1") CO J=3-2 interferometric mapping using the Submillimeter Array (SMA) of IRAS 22036+5306 (I22036), a bipolar preplanetary nebula (PPN) with knotty jets discovered in our HST snapshot survey of young PPNs. In addition, we have obtained supporting lower resolution (approx.10") CO and 13CO J=1-0 observations with the Owens Valley Radio Observatory (OVRO) interferometer, as well as optical long-slit echelle spectra at the Palomar Observatory. The CO J=3-2 observations show the presence of a very fast (approx.220 km/s), highly collimated, massive (0.03 Solar Mass) bipolar outflow with a very large scalar momentum (about 10(exp 39) g cm/s), and the characteristic spatiokinematic structure of bow shocks at the tips of this outflow. The H(alpha) line shows an absorption feature blueshifted from the systemic velocity by approx.100 km/s, which most likely arises in neutral interface material between the fast outflow and the dense walls of the bipolar lobes at low latitudes. The fast outflow in I22036, as in most PPNs, cannot be driven by radiation pressure. We find an unresolved source of submillimeter (and millimeter-wave) continuum emission in I22036, implying a very substantial mass (0.02-0.04 Solar Mass) of large (radius > or approx.1 mm), cold ( or approx.4 Solar Mass) progenitor in which hot-bottom-burning has occurred.

  12. Ring Nebula and Bipolar Outflows Associated with the B1.5 Supergiant Sher #25 in NGC 3603

    CERN Document Server

    Brandner, W; Chu, Y H; Weis, K; Brandner, Wolfgang; Grebel, Eva K.; Chu, You-Hua; Weis, Kerstin

    1996-01-01

    We have identified a ring-shaped emission-line nebula and a possible bipolar outflow centered on the B1.5 supergiant Sher #25 in the Galactic giant HII region NGC 3603 (distance 6 kpc). The clumpy ring around Sher #25 appears to be tilted by 64 deg against the plane of the sky. Its semi-major axis (position angle approx. 165 deg) is 6.9" long, which corresponds to a ring diameter of 0.4 pc. The bipolar outflow filaments, presumably located above and below the ring plane on either side of Sher #25, show a separation of approx. 0.5 pc from the central star. High-resolution spectra show that the ring has a systemic velocity of V_LSR = +19 km/s and a de-projected expansion velocity of 20 km/s, and that one of the bipolar filaments has an outflow speed of approx. 83 km/s. The spectra also show high [NII]/Halpha ratio, suggestive of strong N enrichment. Sher #25 must be an evolved blue supergiant (BSG) past the red supergiant (RSG) stage. We find that the ratio of equatorial to polar mass-loss rate during the red s...

  13. Differential Proper-Motion Measurements of The Cygnus Egg Nebula: The Presence of Equatorial Outflow

    CERN Document Server

    Ueta, Toshiya; Ferguson, Brian A

    2013-01-01

    We present the results of differential proper-motion analyses of the Egg Nebula (RAFGL 2688, V1610 Cyg) based on the archived two-epoch optical data taken with the Hubble Space Telescope. First, we determined that the polarization characteristics of the Egg Nebula is influenced by the higher optical depth of the central regions of the nebula (i.e., the "dustsphere" of about 1000 AU radius), causing the nebula illuminated in two steps -- the direct starlight is first channeled into bipolar cavities and then scattered off to the rest of the nebula. We then measured the amount of motion of local structures and the signature concentric arcs by determining their relative shifts over the 7.25 yr interval. Based on our analysis, which does not rely on the single-scattering assumption, we concluded that the lobes have been excavated by a linear expansion along the bipolar axis for the past 400 yr, while the concentric arcs have been generated continuously and moving out radially at about 10 km/s for the past 5,500 yr...

  14. An Extreme High-Velocity Bipolar Outflow in the Pre-Planetary Nebula IRAS 08005-2356

    CERN Document Server

    Sahai, R

    2015-01-01

    We report interferometric mapping of the bipolar pre-planetary nebula IRAS 08005-2356 with an angular-resolution of ~1"-5", using the Submillimeter Array (SMA), in the 12CO J=2-1, 3-2, 13CO J=2-1 and SiO J=5-4 (v=0) lines. Single-dish observations, using the SMT 10-m, were made in these lines as well as in the CO J=4-3 and SiO J-6-5 (v=0) lines. The lines profiles are very broad, showing the presence of a massive (>0.1 Msun), extreme high-velocity outflow (V~200 km/s) directed along the nebular symmetry axis derived from the HST imaging of this object. The outflow's scalar momentum far exceeds that available from radiation pressure of the central post-AGB star, and it may be launched from an accretion disk around a main-sequence companion. We provide indirect evidence for such a disk from its previously published, broad H-alpha emission profile, which we propose results from Ly-beta emission generated in the disk followed by Raman-scattering in the innermost regions of a fast, neutral wind.

  15. An Extreme High-velocity Bipolar Outflow in the Pre-planetary Nebula IRAS 08005-2356

    Science.gov (United States)

    Sahai, R.; Patel, N. A.

    2015-09-01

    We report interferometric mapping of the bipolar pre-planetary nebula IRAS 08005-2356 (I 08005) with an angular resolution of ˜1″-5″, using the Submillimeter Array, in the 12CO J = 2-1, 3-2, 13CO J = 2-1, and SiO J = 5-4 (v = 0) lines. Single-dish observations, using the SMT 10 m, were made in these lines as well as in the CO J = 4-3 and SiO J = 6-5 (v = 0) lines. The line profiles are very broad, showing the presence of a massive (>0.1 M⊙), extreme high velocity outflow (V ˜ 200 km s-1) directed along the nebular symmetry axis derived from the Hubble Space Telescope imaging of this object. The outflow's scalar momentum far exceeds that available from radiation pressure of the central post-AGB star, and it may be launched from an accretion disk around a main-sequence companion. We provide indirect evidence for such a disk from its previously published, broad Hα emission profile, which we propose results from Lyβ emission generated in the disk followed by Raman-scattering in the innermost regions of a fast, neutral wind.

  16. AN EXTREME HIGH-VELOCITY BIPOLAR OUTFLOW IN THE PRE-PLANETARY NEBULA IRAS 08005-2356

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, R. [Jet Propulsion Laboratory, California Institute of Technology, MS 183-900, Pasadena, CA 91109 (United States); Patel, N. A., E-mail: raghvendra.sahai@jpl.nasa.gov [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

    2015-09-01

    We report interferometric mapping of the bipolar pre-planetary nebula IRAS 08005-2356 (I 08005) with an angular resolution of ∼1″–5″, using the Submillimeter Array, in the {sup 12}CO J = 2–1, 3–2, {sup 13}CO J = 2–1, and SiO J = 5–4 (v = 0) lines. Single-dish observations, using the SMT 10 m, were made in these lines as well as in the CO J = 4–3 and SiO J = 6–5 (v = 0) lines. The line profiles are very broad, showing the presence of a massive (>0.1 M{sub ⊙}), extreme high velocity outflow (V ∼ 200 km s{sup −1}) directed along the nebular symmetry axis derived from the Hubble Space Telescope imaging of this object. The outflow's scalar momentum far exceeds that available from radiation pressure of the central post-AGB star, and it may be launched from an accretion disk around a main-sequence companion. We provide indirect evidence for such a disk from its previously published, broad Hα emission profile, which we propose results from Lyβ emission generated in the disk followed by Raman-scattering in the innermost regions of a fast, neutral wind.

  17. Hu1-2: a metal-poor bipolar planetary nebula with fast collimated outflows

    CERN Document Server

    Fang, Xuan; Miranda, Luis F; Riera, Angels; Velazquez, Pablo F; Raga, Alejandro C

    2015-01-01

    We present narrow-band optical and near-IR imaging and optical long-slit spectroscopic observations of Hu1-2, a Galactic planetary nebula (PN) with a pair of [N II]-bright, fast-moving (> 340 km/s) bipolar knots. Intermediate-dispersion spectra are used to derive physical conditions and abundances across the nebula, and high-dispersion spectra to study the spatio-kinematical structure. Generally Hu1-2 has high He/H (~0.14) and N/O ratios (~0.9), typical of Type I PNe. On the other hand, its abundances of O, Ne, S, and Ar are low as compared with the average abundances of Galactic bulge and disc PNe. The position-velocity maps can be generally described as an hour-glass shaped nebula with bipolar expansion, although the morphology and kinematics of the innermost regions cannot be satisfactorily explained with a simple, tilted equatorial torus. The spatio-kinematical study confines the inclination angle of its major axis to be within 10 degrees of the plane of sky. As in the irradiated bow-shocks of IC4634 and ...

  18. Resolving the Multiple Outflows in the Egg Nebula with Keck II Laser Guide Star Adaptive Optics

    CERN Document Server

    Mignant, D Le; Bouchez, A; Campbell, R; van Dam, M; Chin, J; Johansson, E; Hartman, S; Lafon, R; Lyke, J; Stomski, P; Summers, D; Wizinowich, P

    2007-01-01

    The Egg Nebula has been regarded as the archetype of bipolar proto-planetary nebulae, yet we lack a coherent model that can explain the morphology and kinematics of the nebular and dusty components observed at high-spatial and spectral resolution. Here, we report on two sets of observations obtained with the Keck Adaptive Optics Laser Guide Star: H to M-band NIRC2 imaging, and narrow bandpath K-band OSIRIS 3-D imaging-spectroscopy (through the H2 2.121micron emission line). While the central star or engine remains un-detected at all bands, we clearly resolve the dusty components in the central region and confirm that peak A is not a companion star. The spatially-resolved spectral analysis provide kinematic information of the H_2 emission regions in the eastern and central parts of the nebula and show projected velocities for the H_2 emission higher than 100 km/s. We discuss these observations against a possible formation scenario for the nebular components.

  19. THE FIRST ''WATER FOUNTAIN'' COLLIMATED OUTFLOW IN A PLANETARY NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Gómez, José F.; Miranda, Luis F.; Guerrero, Martín A. [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Suárez, Olga; Bendjoya, Philippe; Lagadec, Eric [Laboratoire Lagrange, UMR 7293, Université de Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d' Azur, F-06304 Nice (France); Rizzo, J. Ricardo; García-García, Enrique [Centro de Astrobiología (INTA-CSIC), Ctra. M-108, km. 4, E-28850 Torrejón de Ardoz (Spain); Green, James A. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710 (Australia); Uscanga, Lucero [Institute of Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, 15236 Athens (Greece); Ramos-Larios, Gerardo [Instituto de Astronomía y Meteorología, Av. Vallarta No. 2602, Col. Arcos Vallarta, C.P. 44130 Guadalajara, Jalisco (Mexico)

    2015-02-01

    ''Water fountains'' (WFs) are evolved objects showing high-velocity, collimated jets traced by water maser emission. Most of them are in the post-asymptotic giant branch (post-AGB) and they may represent one of the first manifestations of collimated mass loss in evolved stars. We present water maser, carbon monoxide, and mid-infrared spectroscopic data (obtained with the Australia Telescope Compact Array, Herschel Space Observatory, and the Very Large Telescope, respectively) toward IRAS 15103–5754, a possible planetary nebula (PN) with WF characteristics. Carbon monoxide observations show that IRAS 15103–5754 is an evolved object, while the mid-IR spectrum displays unambiguous [Ne II] emission, indicating that photoionization has started and thus, its nature as a PN is confirmed. Water maser spectra show several components spreading over a large velocity range (≅ 75 km s{sup –1}) and tracing a collimated jet. This indicates that the object is a WF, the first WF known that has already entered the PN phase. However, the spatial and kinematical distribution of the maser emission in this object are significantly different from those in other WFs. Moreover, the velocity distribution of the maser emission shows a ''Hubble-like'' flow (higher velocities at larger distances from the central star), consistent with a short-lived, explosive mass-loss event. This velocity pattern is not seen in other WFs (which are presumably in earlier evolutionary stages). We therefore suggest that we are witnessing a fundamental change of mass-loss processes in WFs, with water masers being pumped by steady jets in post-AGB stars, but tracing explosive/ballistic events as the object enters the PN phase.

  20. A Massive Bipolar Outflow and a Dusty Torus with Large Grains in the Pre-Planetary Nebula IRAS 22036+5306

    CERN Document Server

    Sahai, R; Patel, N A; Contreras, C S; Morris, M

    2006-01-01

    We report high angular-resolution (~1") CO J=3--2 interferometric mapping, using the Submillimeter Array (SMA), of IRAS22036+5306 (I22036), a bipolar pre-planetary nebula (PPN) with knotty jets discovered in our HST SNAPshot survey of young PPNs. In addition, we have obtained supporting lower-resolution (~10") CO and 13CO J=1-0 observations with the Owens Valley Radio Observatory (OVRO) interferometer, as well as optical long-slit echelle spectra at the Palomar Observatory. The CO J=3-2 observations show the presence of a very fast (~220 km/s), highly collimated, massive (0.03 Msun) bipolar outflow with a very large scalar momentum (about 10^{39} g cm s^{-1}), and the characteristic spatio-kinematic structure of bow-shocks at the tips of this outflow. The Halpha line shows an absorption feature blue-shifted from the systemic velocity by ~100 km/s, which most likely arises in neutral interface material between the fast outflow and the dense walls of the bipolar lobes at low latitudes. The fast outflow in I2203...

  1. The Coldest Object in the Universe: Probing the Mass Distribution of the Ultra-Cold Outflow and Dusty Disk in the Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W.; Nyman, L.

    2015-12-01

    Our Cycle 0 ALMA observations confirmed that the Boomerang Nebula is the coldest known object in the Universe, with a massive high-speed outflow that has cooled significantly below the temperature of the cosmic background (CMB). The Boomerang's prodigious mass-loss rate (0.001M⊙) and low-luminosity (300L⊙) make it a key object for understanding the remarkable transition of the circumstellar envelopes of AGB stars into bipolar planetary nebulae. We have obtained new ACA CO 1-0 data that recover much of the flux lost in the Cycle 0 data, and reveal heretofore unseen distant regions of the ultra-cold outflow re-heated to temperatures above the CMB. Our CO J=3-2 data reveal the precise, highly collimated shape of an inner bipolar structure and its dense central waist, with unprecedented angular resolution (0.4”). The waist shows a core-halo structure in the thermal dust emission at 0.88 mm, and its derived flux at this wavelength, compared with the 3.3, 2.6, and 1.3 mm fluxes support the presence of about 5×10-4 M⊙ of very large (˜mm-sized), cold (˜30K) grains. We also find the unexpected presence of weak SO emission, possibly resulting from the release of S from grains due to high-speed shocks.

  2. Sculpting an AGB Mass-Loss Envelope into a Bipolar Planetary Nebula: High-Velocity Outflows in V Hydrae

    CERN Document Server

    Sahai, Raghvendra; Hinkle, Kenneth

    2009-01-01

    We have carried out high-resolution spectroscopic observations of the carbon star V Hya, covering the 4.6 micron band of CO. These data, taken over 7 epochs, show that the circumstellar environment of V Hya consists of a complex high-velocity (HV) outflow containing at least six kinematic components with expansion velocities ranging between 70 and 120 km/s, together with a slow-moving normal outflow at about 10 km/s. Physical changes occur in the HV outflow regions on a time-scale as short as two days, limiting their extent to < ~ 10^{16} cm. The intrinsic line-width for each HV component is quite large (6-8 km/s) compared to the typical values (~1 km/s) appropriate for normal AGB circumstellar envelopes (CSEs), due to excess turbulence and/or large velocity gradients resulting from the energetic interaction of the HV outflow with the V Hya CSE. We have modelled the absorption features to set constraints on the temperature distribution in, and the mass ejection-rates for gas in the main HV components.

  3. Waiting in the Wings: Reflected X-ray Emission from the Homunculus Nebula

    CERN Document Server

    Corcoran, M F; Gull, T R; Davidson, K; Petre, R; Hillier, D J; Smith, N; Damineli, A; Morse, J A; Walborn, N R; Verner, E; Collins, N; White, S; Pittard, J M; Weis, K; Bomans, D; Butt, Y

    2004-01-01

    We report the first detection of X-ray emission associated with the Homunculus Nebula which surrounds the supermassive star Eta Carinae. The emission is characterized by a temperature in excess of 100 MK, and is consistent with scattering of the time-delayed X-ray flux associated with the star. The nebular emission is bright in the northwestern lobe and near the central regions of the Homunculus, and fainter in the southeastern lobe. We also report the detection of an unusually broad Fe K fluorescent line, which may indicate fluorescent scattering off the wind of a companion star or some other high velocity outflow. The X-ray Homunculus is the nearest member of the small class of Galactic X-ray reflection nebulae, and the only one in which both the emitting and reflecting sources are distinguishable.

  4. [Fe II] jets from intermediate-mass protostars in Carina

    CERN Document Server

    Reiter, Megan; Bally, John

    2016-01-01

    We present new HST/WFC3-IR narrowband [Fe II] images of protostellar jets in the Carina Nebula. Combined with 5 previously published sources, we have a sample of 18 jets and 2 HH objects. All of the jets we targeted with WFC3 show bright infrared [Fe II] emission, and a few H$\\alpha$ candidate jets are confirmed as collimated outflows based on the morphology of their [Fe II] emission. Continuum-subtracted images clearly separate jet emission from the adjacent ionization front, providing a better tracer of the collimated jet than H$\\alpha$ and allowing us to connect these jets with their embedded driving sources. The [Fe II] 1.64 $\\mu$m/H$\\alpha$ flux ratio measured in the jets is $\\gtrsim 5$ times larger than in the adjacent ionization fronts. The low-ionization jet core requires high densities to shield Fe$^+$ against further ionization by the FUV radiation from O-type stars in the H II region. High jet densities imply high mass-loss rates, consistent with the intermediate-mass driving sources we identify fo...

  5. Spectrophotometry of the shell around AG Carinae

    Science.gov (United States)

    Mitra, P. Mila; Dufour, Reginald J.

    1990-01-01

    Spatially-resolved long-slit spectrophotometry are presented for two regions of the shell nebula around the P-Cygni variable star AG Carinae. The spectra cover the 3700-6800 A wavelength range. Emission-line diagnostics are used to derive extinction, electron temperatures, and densities for various positions in the nebula. The chemical abundances and ionization structure are calculated and compared with other types of planetary nebulae and shells around other luminous stars. It is found that the N/O and N/S ratios of Ag Car are high compared to solar neighborhood ISM values. The O/H depletion found for the AG Car shell approaches that found in the condensations of the Eta Car system.

  6. Collimated outflows in planetary nebulae

    Directory of Open Access Journals (Sweden)

    J. A. López

    2000-01-01

    Full Text Available Nuestro entendimiento sobre la formaci on de nebulosas planetarias (PNe ha sido profundamente in uenciado en a~nos recientes por la detecci on de ujos colimados de alta velocidad en estos objetos. Flujos que alcanzan velocidades de expansi on de varios cientos de km s

  7. Illuminating gas in-/outflows in the MUSE deepest fields: discovery of Ly-alpha nebulae around forming galaxies at z~3.3

    CERN Document Server

    Vanzella, E; Gronke, M; Karman, W; Caminha, G B; Dijkstra, M; Rosati, P; De Barros, S; Caputi, K; Grillo, C; Tozzi, P; Meneghetti, M; Mercurio, A; Gilli, R

    2016-01-01

    We report on the discovery of extended Ly-alpha nebulae at z~3.3 in the Hubble Ultra Deep Field (HUDF, ~ 40 kpc X 80 kpc) and behind the Hubble Frontier Fields galaxy cluster MACSJ0416 (~ 40kpc), spatially associated with groups of star-forming galaxies. VLT/MUSE integral field spectroscopy reveals a complex structure with a spatially-varying double peaked Ly-alpha emission. Overall, the spectral profiles of the two Ly-alpha nebulae are remarkably similar, both showing a prominent blue emission, more intense and slightly broader than the red peak. From the first nebula, located in the HUDF, no X-ray emission has been detected, disfavoring the possible presence of AGNs. Spectroscopic redshifts have been derived for 11 galaxies within two arcsec from the nebula and spanning the redshift range 1.037nebula, behind MACSJ0416, shows three aligned star-forming galaxies plausibly associated to the emitting gas. In both systems, the associated galaxies reveal possible intense rest-frame-optic...

  8. Illuminating gas inflows/outflows in the MUSE deepest fields: Lyα nebulae around forming galaxies at z ≃ 3.3

    Science.gov (United States)

    Vanzella, E.; Balestra, I.; Gronke, M.; Karman, W.; Caminha, G. B.; Dijkstra, M.; Rosati, P.; De Barros, S.; Caputi, K.; Grillo, C.; Tozzi, P.; Meneghetti, M.; Mercurio, A.; Gilli, R.

    2017-03-01

    We report the identification of extended Lyα nebulae at z ≃ 3.3 in the Hubble Ultra Deep Field (HUDF, ≃40 kpc × 80 kpc) and behind the Hubble Frontier Field galaxy cluster MACSJ0416 (≃40 kpc), spatially associated with groups of star-forming galaxies. VLT/MUSE integral field spectroscopy reveals a complex structure with a spatially varying double-peaked Lyα emission. Overall, the spectral profiles of the two Lyα nebulae are remarkably similar, both showing a prominent blue emission, more intense and slightly broader than the red peak. From the first nebula, located in the HUDF, no X-ray emission has been detected, disfavouring the possible presence of active galactic nuclei. Spectroscopic redshifts have been derived for 11 galaxies within 2 arcsec from the nebula and spanning the redshift range 1.037 masses per year. A possible scenario is that of a group of young, star-forming galaxies emitting ionizing radiation that induces Lyα fluorescence, therefore revealing the kinematics of the surrounding gas. Also Lyα powered by star formation and/or cooling radiation may resemble the double-peaked spectral properties and the morphology observed here. If the intense blue emission is associated with inflowing gas, then we may be witnessing an early phase of galaxy or a proto-cluster (or group) formation.

  9. Illuminating gas inflows/outflows in the MUSE deepest fields : Lyα nebulae around forming galaxies at z ≃ 3.3

    NARCIS (Netherlands)

    Vanzella, E.; Balestra, I.; Gronke, M.; Karman, W.; Caminha, G. B.; Dijkstra, M.; Rosati, P.; De Barros, S.; Caputi, K.; Grillo, C.; Tozzi, P.; Meneghetti, M.; Mercurio, A.; Gilli, R.

    2017-01-01

    We report on the discovery of extended Ly-alpha nebulae at z~3.3 in the Hubble Ultra Deep Field (HUDF, ~ 40 kpc X 80 kpc) and behind the Hubble Frontier Fields galaxy cluster MACSJ0416 (~ 40kpc), spatially associated with groups of star-forming galaxies. VLT/MUSE integral field spectroscopy reveals

  10. An Introduction to the Chandra Carina Complex Project

    CERN Document Server

    Townsley, Leisa K; Corcoran, Michael F; Feigelson, Eric D; Gagné, Marc; Montmerle, Thierry; Oey, M S; Smith, Nathan; Garmire, Gordon P; Getman, Konstantin V; Povich, Matthew S; Evans, Nancy Remage; Nazé, Yaël; Parkin, E R; Preibisch, Thomas; Wang, Junfeng; Wolk, Scott J; Chu, You-Hua; Cohen, David H; Gruendl, Robert A; Hamaguchi, Kenji; King, Robert R; Mac Low, Mordecai-Mark; McCaughrean, Mark J; Moffat, Anthony F J; Oskinova, L M; Pittard, Julian M; Stassun, Keivan G; ud-Doula, Asif; Walborn, Nolan R; Waldron, Wayne L; Churchwell, Ed; Nichols, J S; Owocki, Stanley P; Schulz, N S

    2011-01-01

    The Great Nebula in Carina provides an exceptional view into the violent massive star formation and feedback that typifies giant HII regions and starburst galaxies. We have mapped the Carina star-forming complex in X-rays, using archival Chandra data and a mosaic of 20 new 60ks pointings using the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer, as a testbed for understanding recent and ongoing star formation and to probe Carina's regions of bright diffuse X-ray emission. This study has yielded a catalog of properties of >14,000 X-ray point sources; >9800 of them have multiwavelength counterparts. Using Chandra's unsurpassed X-ray spatial resolution, we have separated these point sources from the extensive, spatially-complex diffuse emission that pervades the region; X-ray properties of this diffuse emission suggest that it traces feedback from Carina's massive stars. In this introductory paper, we motivate the survey design, describe the Chandra observations, and present some simple results, pr...

  11. Birth and early evolution of a planetary nebula

    CERN Document Server

    Bobrowsky, M; Parthasarathy, M; García-Lario, P

    1998-01-01

    The final expulsion of gas by a star as it forms a planetary nebula --- the ionized shell of gas often observed surrounding a young white dwarf --- is one of the most poorly understood stages of stellar evolution. Such nebulae form extremely rapidly (about 100 years for the ionization) and so the formation process is inherently difficult to observe. Particularly puzzling is how a spherical star can produce a highly asymmetric nebula with collimated outflows. Here we report optical observations of the Stingray Nebula which has become an ionized planetary nebula within the past few decades. We find that the collimated outflows are already evident, and we have identified the nebular structure that focuses the outflows. We have also found a companion star, reinforcing previous suspicions that binary companions play an important role in shaping planetary nebulae and changing the direction of successive outflows.

  12. HH 666: different kinematics from H α and [Fe II] emission provide a missing link between jets and outflows

    Science.gov (United States)

    Reiter, Megan; Smith, Nathan; Kiminki, Megan M.; Bally, John

    2015-06-01

    HH 666 is an externally irradiated protostellar outflow in the Carina nebula for which we present new near-IR [Fe II] spectra obtained with the Folded-Port Infrared Echellette spectrograph at Magellan Observatory. Earlier H α and near-IR [Fe II] imaging revealed that the two emission lines trace substantially different morphologies in the inner ˜40 arcsec of the outflow. H α traces a broad cocoon that surrounds the collimated [Fe II] jet that extends throughout the parent dust pillar. New spectra show that this discrepancy extends to their kinematics. Near-IR [Fe II] emission traces steady, fast velocities of ±200 km s-1 from the eastern and western limbs of the jet. We compare this to a previously published H α spectrum that reveals a Hubble-flow velocity structure near the jet-driving source. New, second-epoch Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) H α images reveal the lateral spreading of the H α outflow lobe away from the jet axis. H α proper motions also indicate a sudden increase in the mass-loss rate ˜1000 yr ago, while steady [Fe II] emission throughout the inner jet suggest that the burst is ongoing. An accretion burst sustained for ˜1000 yr is an order of magnitude longer than expected for FU Orionis outbursts, but represents only a small fraction of the total age of the HH 666 outflow. Altogether, available data suggests that [Fe II] traces the highly collimated protostellar jet while H α traces the entrained and irradiated outflow. HH 666 appears to be a missing link between bare jets seen in H II regions and entrained molecular outflows seen from embedded protostars in more quiescent regions.

  13. HH 666: Different kinematics from H{\\alpha} and [Fe II] emission provide a missing link between jets and outflows

    CERN Document Server

    Reiter, Megan; Kiminki, Megan M; Bally, John

    2015-01-01

    HH 666 is an externally irradiated protostellar outflow in the Carina Nebula for which we present new near-IR [Fe II] spectra obtained with the FIRE spectrograph at Magellan Observatory. Earlier H{\\alpha} and near-IR [Fe II] imaging revealed that the two emission lines trace substantially different morphologies in the inner ~40" of the outflow. H{\\alpha} traces a broad cocoon that surrounds the collimated [Fe II] jet that extends throughout the parent dust pillar. New spectra show that this discrepancy extends to their kinematics. Near-IR [Fe II] emission traces steady, fast velocities of +/- 200 km/s from the eastern and western limbs of the jet. We compare this to a previously published H{\\alpha} spectrum that reveals a Hubble-flow velocity structure near the jet-driving source. New, second-epoch HST/ACS H{\\alpha} images reveal the lateral spreading of the H{\\alpha} outflow lobe away from the jet axis. H{\\alpha} proper motions also indicate a sudden increase in the mass-loss rate ~1000 yr ago, while steady ...

  14. HST/WFC3 Imaging of Protostellar Jets in Carina: [Fe II] Emission Tracing Massive Jets from Intermediate Mass Protostars

    CERN Document Server

    Reiter, Megan

    2013-01-01

    We present narrowband WFC3-UVIS and -IR images of four externally irradiated protostellar jets in the Carina nebula: HH666, HH901, HH902, and HH1066. These massive jets are unusual because they are bathed in UV radiation from dozens of nearby O stars, but despite the strong incident ionizing radiation, portions of the jet remain neutral. Near-IR [Fe II] images reveal dense, neutral gas that was not seen in previous studies of H-alpha emission. We show that near-IR [Fe II] emitting gas must be self-shielded from Lyman continuum photons, regardless of its excitation mechanism (shocks, FUV radiation, or both). High densities are required for the survival of Fe+ amid the strong Lyman continuum from Tr14, raising estimates of the mass-loss rates by an order of magnitude. Higher jet mass-loss rates require higher accretion rates onto their driving protostars, implying that these jets are driven by intermediate-mass (IM; ~2-8 Msun) stars. Indeed, the IR driving sources of two of these outflows have luminosities that...

  15. Spatial distribution and kinematics of the molecular material associated with $\\eta$ Carinae

    CERN Document Server

    Loinard, L; Serra, P; Menten, K; Zapata, L; Rodriguez, L

    2016-01-01

    Single-dish sub-millimeter observations have recently revealed the existence of a substantial, chemically peculiar, molecular gas component located in the innermost circumstellar environment of the very massive luminous blue variable star $\\eta$ Carinae. Here, we present 5$"$-resolution interferometric observations of the 1$\\rightarrow$0 rotational transition of hydrogen cyanide (HCN) obtained with the Australia Telescope Compact Array (ATCA) toward this star. The emission is concentrated in the central few arcseconds around $\\eta$ Carinae and shows a clear 150 km s$^{-1}$ velocity gradient running from west-north-west (blue) to east-south-east (red). Given the extent and location of this molecular material, we associate it with the complex of dusty arcs and knots seen in mid-infrared emission along the equatorial plane of the Homunculus nebula. The dust located in the central few arcseconds around $\\eta$ Carinae and the molecular component described here have most likely formed in situ, out of material expel...

  16. A Catalog of New Spectroscopically Confirmed Massive OB Stars in Carina

    CERN Document Server

    Alexander, Michael J; Povich, Matthew S; McSwain, M Virginia

    2016-01-01

    The Carina star-forming region is one of the largest in the Galaxy, and its massive star population is still being unveiled. The large number of stars combined with high, and highly variable, interstellar extinction makes it inherently difficult to find OB stars in this type of young region. We present the results of a spectroscopic campaign to study the massive star population of the Carina Nebula, with the primary goal to confirm or reject previously identified Carina OB star candidates. A total of 141 known O- and B-type stars and 94 candidates were observed, of which 73 candidates had a high enough signal-to-noise ratio to classify. We find 23 new OB stars within the Carina Nebula, a 32% confirmation rate. One of the new OB stars has blended spectra and is suspected to be a double-lined spectroscopic binary (SB2). We also reclassify the spectral types of the known OB stars and discover nine new SB2s among this population. Finally, we discuss the spatial distribution of these new OB stars relative to known...

  17. Spatial Distribution and Kinematics of the Molecular Material Associated with eta Carinae

    Science.gov (United States)

    Loinard, Laurent; Kamiński, Tomasz; Serra, Paolo; Menten, Karl M.; Zapata, Luis A.; Rodríguez, Luis F.

    2016-12-01

    Single-dish submillimeter observations have recently revealed the existence of a substantial, chemically peculiar molecular gas component located in the innermost circumstellar environment of the very massive luminous blue variable star, η Carinae. Here, we present 5″-resolution interferometric observations of the 1\\to 0 rotational transition of hydrogen cyanide (HCN) toward this star obtained with the Australia Telescope Compact Array. The emission is concentrated in the central few arcseconds around η Carinae and shows a clear 150 km s-1 velocity gradient running from west-north-west (blue) to east-south-east (red). Given the extent, location, and kinematics of this molecular material, we associate it with the complex of dusty arcs and knots seen in mid-infrared emission near the center of the Homunculus nebula. Indeed, the shielding provided by this dust could help explain how molecules survive in the presence of the intense UV radiation field produced by η Carinae. The dust located in the central few arcseconds around η Carinae and the molecular component described here most likely formed in situ and out of material expelled by the massive interacting binary system. Thus, η Carinae offers us a rare glimpse of the processes that lead to the formation of dust and molecules around massive stars, which are relevant to the interpretation of dust and molecule detections at high redshifts.

  18. FUSE Observations of eta Carinae

    CERN Document Server

    Iping, R C; Gull, T R

    2004-01-01

    Eta Carinae was observed by FUSE through the LWRS (30 arcsec x30 arcsec) and HIRS (1.25 arcsec x 20 arcsec) apertures in March and April 2004. There are significant differences between the two spectra. About half of the LWRS flux appears to be due to two B-type stars near the edge of the LWRS aperture, 14 arcsec from eta Carinae. The HIRS spectrum (LiF1 channel) therefore reveals the intrinsic FUV spectrum of eta Carinae without this stellar contamination. The HIRS spectrum contains strong interstellar H2 having high rotational excitation (up to J=8). Most of the atomic species with prominent ISM features (C II, Fe II, Ar I, P II, etc) also have strong blue-shifted absorption to v= ~ -580 km/s that is associated with expanding debris from the 1840 eruption.

  19. The sub-arcsecond dusty environment of Eta Carinae

    CERN Document Server

    Chesneau, O; Herbst, T; Waters, L B F M; Hillier, D J; Leinert, C; De Koter, A; Pascucci, I; Jaffe, W; Köhler, R; Alvarez, C; Van Boekel, R; Brandner, W; Graser, U; Lagrange, A M; Lenzen, R; Morel, S; Schöller, M; Leinert, Ch

    2005-01-01

    The core of the nebula surrounding Eta Carinae has been observed with the VLT Adaptive Optics system NACO and with the interferometer VLTI/MIDI to constrain spatially and spectrally the warm dusty environment and the central object. In particular, narrow-band images at 3.74 and 4.05 micron reveal the butterfly shaped dusty environment close to the central star with unprecedented spatial resolution. A void whose radius corresponds to the expected sublimation radius has been discovered around the central source. Fringes have been obtained in the Mid-IR which reveal a correlated flux of about 100Jy situated 0.3" south-east of the photocenter of the nebula at 8.7 micron, which corresponds with the location of the star as seen in other wavelengths. This correlated flux is partly attributed to the central object, and these observations provide an upper limit for the SED of the central source from 2.2 to 13.5 micron. Moreover, we have been able to spectrally disperse the signal from the nebula itself at PA=318 degre...

  20. 'Peony Nebula' Star Settles for Silver Medal

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Poster Version Movie If our galaxy, the Milky Way, were to host its own version of the Olympics, the title for the brightest known star would go to a massive star called Eta Carina. However, a new runner-up now the second-brightest star in our galaxy has been discovered in the galaxy's dusty and frenzied interior. This image from NASA's Spitzer Space Telescope shows the new silver medalist, circled in the inset above, in the central region of our Milky Way. Dubbed the 'Peony nebula' star, this blazing ball of gas shines with the equivalent light of 3.2 million suns. The reigning champ, Eta Carina, produces the equivalent of 4.7 million suns worth of light though astronomers say these estimates are uncertain, and it's possible that the Peony nebula star could be even brighter than Eta Carina. If the Peony star is so bright, why doesn't it stand out more in this view? The answer is dust. This star is located in a very dusty region jam packed with stars. In fact, there could be other super bright stars still hidden deep in the stellar crowd. Spitzer's infrared eyes allowed it to pierce the dust and assess the Peony nebula star's true brightness. Likewise, infrared data from the European Southern Observatory's New Technology Telescope in Chile were integral in calculating the Peony nebula star's luminosity. The Peony nebula, which surrounds the Peony nebular star, is the reddish cloud of dust in and around the white circle. The movie begins by showing a stretch of the dusty and frenzied central region of our Milky Way galaxy. It then zooms in to reveal the 'Peony nebula' star the new second-brightest star in the Milky Way, discovered in part by NASA's Spitzer Space Telescope. This is a three-color composite showing infrared observations from two Spitzer instruments. Blue represents 3.6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array

  1. Protostellar Outflows

    Science.gov (United States)

    Bally, John

    2016-09-01

    Outflows from accreting, rotating, and magnetized systems are ubiquitous. Protostellar outflows can be observed from radio to X-ray wavelengths in the continuum and a multitude of spectral lines that probe a wide range of physical conditions, chemical phases, radial velocities, and proper motions. Wide-field visual and near-IR data, mid-IR observations from space, and aperture synthesis with centimeter- and millimeterwave interferometers are revolutionizing outflow studies. Many outflows originate in multiple systems and clusters. Although most flows are bipolar and some contain highly collimated jets, others are wide-angle winds, and a few are nearly isotropic and exhibit explosive behavior. Morphologies and velocity fields indicate variations in ejection velocity, mass-loss rate, and in some cases, flow orientation and degree of collimation. These trends indicate that stellar accretion is episodic and often occurs in a complex dynamical environment. Outflow power increases with source luminosity but decreases with evolutionary stage. The youngest outflows are small and best traced by molecules such as CO, SiO, H2O, and H2. Older outflows can grow to parsec scales and are best traced by shock-excited atoms and ions such as hydrogen-recombination lines, [Sii], and [Oii]. Outflows inject momentum and energy into their surroundings and provide an important mechanism in the self-regulation of star formation. However, momentum injection rates remain uncertain with estimates providing lower bounds.

  2. Atlantic CFC data in CARINA

    Directory of Open Access Journals (Sweden)

    R. Steinfeldt

    2010-01-01

    Full Text Available Water column data of carbon and carbon-relevant parameters have been collected and merged into a new database called CARINA (CARbon IN the Atlantic. In order to provide a consistent data set, all data have been examined for systematic biases and adjusted if necessary (secondary quality control (QC. The CARINA data set is divided into three regions: the Arctic/Nordic Seas, the Atlantic region and the Southern Ocean. Here we present the CFC data for the Atlantic region, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113 as well as carbon tetrachloride (CCl4. The methods applied for the secondary quality control, a crossover analyses, the investigation of CFC ratios in the ocean and the CFC surface saturation are presented. Based on the results, the CFC data of some cruises are adjusted by a certain factor or given a "poor'' quality flag.

  3. Arctic Ocean data in CARINA

    Directory of Open Access Journals (Sweden)

    S. Jutterström

    2010-02-01

    Full Text Available The paper describes the steps taken for quality controlling chosen parameters within the Arctic Ocean data included in the CARINA data set and checking for offsets between the individual cruises. The evaluated parameters are the inorganic carbon parameters (total dissolved inorganic carbon, total alkalinity and pH, oxygen and nutrients: nitrate, phosphate and silicate. More parameters can be found in the CARINA data product, but were not subject to a secondary quality control. The main method in determining offsets between cruises was regional multi-linear regression, after a first rough basin-wide deep-water estimate of each parameter. Lastly, the results of the secondary quality control are discussed as well as applied adjustments.

  4. Arctic Ocean data in CARINA

    Directory of Open Access Journals (Sweden)

    S. Jutterström

    2009-08-01

    Full Text Available The paper describes the steps taken for quality controlling chosen parameters within the Arctic Ocean data included in the CARINA data set and checking for offsets between the individual cruises. The evaluated parameters are the inorganic carbon parameters (total dissolved inorganic carbon, total alkalinity and pH, oxygen and nutrients: nitrate, phosphate and silicate. More parameters can be found in the CARINA data product, but were not subject to a secondary quality control. The main method in determining offsets between cruises was regional multi-linear regression, after a first rough basin-wide deep-water estimate of each parameter. Lastly, the results of the secondary quality control are discussed as well as suggested adjustments.

  5. Observing nebulae

    CERN Document Server

    Griffiths, Martin

    2016-01-01

    This book enables anyone with suitable instruments to undertake an examination of nebulae and see or photograph them in detail. Nebulae, ethereal clouds of gas and dust, are among the most beautiful objects to view in the night sky. These star-forming regions are a common target for observers and photographers. Griffiths describes many of the brightest and best nebulae and includes some challenges for the more experienced observer. Readers learn the many interesting astrophysical properties of these clouds, which are an important subject of study in astronomy and astrobiology. Non-mathematical in approach, the text is easily accessible to anyone with an interest in the subject. A special feature is the inclusion of an observational guide to 70 objects personally observed or imaged by the author. The guide also includes photographs of each object for ease of identification along with their celestial coordinates, magnitudes and other pertinent information. Observing Nebulae provides a ready resource to allow an...

  6. The sub-arcsecond dusty environment of Eta Carinae

    Science.gov (United States)

    Chesneau, O.; Min, M.; Herbst, T.; Waters, L. B. F. M.; Leinert, Ch.; Hillier, D. J.

    2005-09-01

    The core of the nebula surrounding Eta Carinae was observed with the VLT Adaptive Optics system NACO and with the interferometer VLTI/MIDI to spatially and spectrally isolate the warm dusty environment and the central object. Narrow-band images at 3.74 μm and 4.05 μm reveal a butterfly shaped dusty environment close to the central star with unprecedented spatial resolution. Fringes have been obtained in the Mid-IR and a correlated flux of about 100 Jy situated 0.3 arcsec south-east from the photocenter of the nebula at 8.7 μm is detected. This flux is partly attributed to the central object and provides an upper limit for the SED of the central source from 3.8 μm to 13.5 μm. We have been able to spectrally disperse the signal from the nebula itself at PA=318 degree, i.e. in the direction of the bipolar nebula (˜310°) within the MIDI field of view of 3 arcsec. A large amount of corundum (Al2O3) is discovered, peaking at 0.6-1.2 arcsec south-east from the star, whereas the dust content of the Weigelt blobs, in the equatorial plane, is dominated by silicates. We propose a geometry for the Butterfly nebulae assuming a similar axis for the large and little Homunculus. We suggest that the Butterfly nebulae is a consequence of the 1890 outburst and is embedded in the Little Homonculus its geometry is, mostly shaped by the local dust formation conditions which are directly affected by the latitudinal dependance of the ejection and the present wind. The dust is mostly formed in the bright rims of the Butterfly nebula. The dust condenses closer to the poles of the star owing to the larger mass-loss rate and the relative velocity between the stellar wind and the ejecta at these latitudes. In this geometry, the bright southern clump directly sees the southern pole of the central object. At intermediate latitudes, the mass-loss rate and the relative velocity of the wind are decreased and dust forms further out. We suggest that the survival and the large mass of the

  7. Astrophysical Jets and Outflows

    CERN Document Server

    De Gouveia dal Pino, E M

    2004-01-01

    Highly collimated supersonic jets and less collimated outflows are observed to emerge from a wide variety of astrophysical objects. They are seen in young stellar objects (YSOs), proto-planetary nebulae, compact objects (like galactic black holes or microquasars, and X-ray binary stars), and in the nuclei of active galaxies (AGNs). Despite their different physical scales (in size, velocity, and amount of energy transported), they have strong morphological similarities. What physics do they share? These systems either hydrodynamic or magnetohydrodynamic (MHD) in nature and are, as such, governed by non-linear equations. While theoretical models helped us to understand the basic physics of these objects, numerical simulations have been allowing us to go beyond the one-dimensional, steady-state approach extracting vital information. In this lecture, the formation, structure, and evolution of the jets are reviewed with the help of observational information, MHD and purely hydrodynamical modeling, and numerical si...

  8. Butterfly Nebula

    Science.gov (United States)

    1997-01-01

    The Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) is back at work, capturing this image of the 'butterfly wing'- shaped nebula, NGC 2346. The nebula is about 2,000 light-years away from Earth in the direction of the constellation Monoceros. It represents the spectacular 'last gasp' of a binary star system at the nebula's center. The image was taken on March 6, 1997 as part of the recommissioning of the Hubble Space Telescope's previously installed scientific instruments following the successful servicing of the HST by NASA shuttle astronauts in February. WFPC2 was installed in HST during the servicing mission in 1993. At the center of the nebula lies a pair of stars that are so close together that they orbit around each other every 16 days. This is so close that, even with Hubble, the pair of stars cannot be resolved into its two components. One component of this binary is the hot core of a star that has ejected most of its outer layers, producing the surrounding nebula. Astronomers believe that this star, when it evolved and expanded to become a red giant, actually swallowed its companion star in an act of stellar cannibalism. The resulting interaction led to a spiraling together of the two stars, culminating in ejection of the outer layers of the red giant. Most of the outer layers were ejected into a dense disk, which can still be seen in the Hubble image, surrounding the central star. Later the hot star developed a fast stellar wind. This wind, blowing out into the surrounding disk, has inflated the large, wispy hourglass-shaped wings perpendicular to the disk. These wings produce the butterfly appearance when seen in projection. The total diameter of the nebula is about one-third of a light-year, or 2 trillion miles.

  9. Dust in the SN1987A-analog SBW1 in Carina

    Science.gov (United States)

    Smith, Nathan

    2009-02-01

    Last year Smith et al. (2007) reported the discovery of a new equatorial ring nebula, called SBW1, around a blue supergiant seen in the Carina Nebula. It has morphology and physical dimensions almost identical to the ring around SN1987A and it surrounds an early B supergiant that is a virtual twin ofthe progenitor of SN1987A. However, it is more than 20 times closer than SN1987A, and therefore shows the detailed structure of this unusual type of ring nebula in much greater detail, before the star explodes. Resolving the structure in this nebula will inform our understanding of non-spherical mass loss from supernova progenitor stars in general, and will constrain models of SN1987A as its blast wave continues to interact with its circumstellar ring. This proposal aims to obtain mid-IR images and spectroscopy of SBW1 with T-ReCS on Gemini South in order to determine the dust properties in the nebula, such as its physical location, temperature, mass, and composition, for comparison with the dust properties of SN1987A's ring and also with the circumstellar dust properties of other blue supergiants like B[e] stars. These IR data are also needed to understand the relationship between warm dust and the ionized gas structures that will be resolved in our accepted program to obtain WFC3 and STIS data with HST.

  10. CARINA: nutrient data in the Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    T. Tanhua

    2009-07-01

    Full Text Available Data on carbon and carbon-relevant hydrographic and hydrochemical parameters from previously non-publicly available cruise data sets in the Arctic, Atlantic and Southern Ocean have been retrieved and merged to a new database: CARINA (CARbon IN the Atlantic. These data have gone through rigorous quality control (QC procedures to assure the highest possible quality and consistency. The data for most of the measured parameters in the CARINA data base were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the data products, i.e. three merged data files with measured, calculated and interpolated data for each of the three CARINA regions; Arctic, Atlantic and Southern Ocean. Out of a total of 188 cruise entries in the CARINA database, 98 were conducted in the Atlantic Ocean and of these 84 cruises report nitrate values, 79 silicate, and 78 phosphate. Here we present details of the secondary QC for nutrients for the Atlantic Ocean part of CARINA. Procedures of quality control, including crossover analysis between cruises and inversion analysis of all crossover data are briefly described. Adjustments were applied to the nutrient values for 43 of the cruises in the Atlantic Ocean region. With these adjustments the CARINA database is consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s (Key et al., 2004. Based on our analysis we estimate the internal accuracy of the CARINA-ATL nutrient data to be: nitrate 1.5%; phosphate 2.6%; silicate 3.1%. The CARINA data are now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation.

  11. Was the nineteenth century giant eruption of Eta Carinae a merger event in a triple system?

    CERN Document Server

    Zwart, Simon Portegies

    2015-01-01

    We discuss the events that led to the giant eruption of Eta Carinae, and find that the mid-nineteenth century (in 1838-1843) giant mass-loss outburst has the characteristics of being produced by the merger event of a massive close binary, triggered by the gravitational interaction with a massive third companion star, which is the current binary companion in the Eta Carinae system. We come to this conclusion by a combination of theoretical arguments supported by computer simulations using the Astrophysical Multipurpose Software Environment. According to this model the $\\sim 90$\\,\\MSun\\, present primary star of the highly eccentric Eta Carinae binary system is the product of this merger, and its $\\sim 30$\\,\\MSun\\, companion originally was the third star in the system. In our model the Homunculus nebula was produced by an extremely enhanced stellar wind, energized by tidal energy dissipation prior to the merger, which enormously boosted the radiation-driven wind mass-loss. The current orbital plane is then align...

  12. Stingray Nebula

    Science.gov (United States)

    1996-01-01

    This Wide Field and Planetary Camera 2 image captures the infancy of the Stingray nebula (Hen-1357), the youngest known planetary nebula. In this image, the bright central star is in the middle of the green ring of gas. Its companion star is diagonally above it at 10 o'clock. A spur of gas (green) is forming a faint bridge to the companion star due to gravitational attraction. The image also shows a ring of gas (green) surrounding the central star, with bubbles of gas to the lower left and upper right of the ring. The wind of material propelled by radiation from the hot central star has created enough pressure to blow open holes in the ends of the bubbles, allowing gas to escape. The red curved lines represent bright gas that is heated by a 'shock' caused when the central star's wind hits the walls of the bubbles. The nebula is as large as 130 solar systems, but, at its distance of 18,000 light-years, it appears only as big as a dime viewed a mile away. The Stingray is located in the direction of the southern constellation Ara (the Altar). The colors shown are actual colors emitted by nitrogen (red), oxygen (green), and hydrogen (blue).

  13. The Stingray nebula: watching the rapid evolution of a newly born planetary nebula.

    Science.gov (United States)

    Bobrowsky, M.; Sahu, K. C.; Parthasarathy, M.; García-Lario, Pedro

    The formation and early evolution of planetary nebulae represent one of the most poorly understood phases of stellar evolution ( Kwok, 1987; Maddox, 1995). One of the youngest, the Stingray Nebula (He3-1357) ( Henize, 1967; Henize, 1976), shows all the tell-tale signs of a newly born planetary nebula: it has become ionized only within the past few decades ( Parthasarathy et al., 1993); the mass-loss from the central star has ceased within the past few years; and the central star is becoming hotter and fainter as expected from a star on its way to becoming a DA white dwarf ( Parthasarathy et al., 1995). The Stingray Nebula thus provides the ideal laboratory for examining the early structure and evolution of this class of objects. Images of the Stingray Nebula, obtained with the Hubble Space Telescope, show for the first time that its multiple expulsions of matter are focused by an equatorial ring and bubbles of gas located on opposite sides of the ring ( Bobrowsky et al., 1995). The position angle of the outflows has changed, possibly as a result of precessional motion induced by the presence of a companion star. This is consistent with the precessing jet model by Livio & Pringle (1996). Indeed, we have reported the discovery of a companion star in the Stingray Nebula ( Bobrowsky et al., 1998). Finally, we present evidence of the companion star dynamically distorting the gas in this newly-born planetary nebula.

  14. Solution to the Sigma-Problem of Pulsar Wind Nebulae

    CERN Document Server

    Porth, Oliver; Keppens, Rony

    2012-01-01

    We present first results of three dimensional relativistic magnetohydrodynamical simulations of Pulsar Wind Nebulae. They show that the kink instability and magnetic dissipation inside these nebulae may be the key processes allowing to reconcile their observations with the theory of pulsar winds. In particular, the size of the termination shock, obtained in the simulations, agrees very well with the observations even for Poynting-dominated pulsar winds. Due to magnetic dissipation the total pressure in the simulated nebulae is particle-dominated and more or less uniform. While in the main body of the simulated nebulae the magnetic field becomes rather randomized, close to the termination shock, it is dominated by the regular toroidal field freshly injected by the pulsar wind. This field is responsible for driving polar outflows and may explain the high polarization observed in pulsar wind nebulae.

  15. The three-dimensional structure of the Eta Carinae Homunculus

    CERN Document Server

    Steffen, W; Madura, T I; Groh, J H; Gull, T R; Mehner, A; Corcoran, M F; Damineli, A; Hamaguchi, K

    2014-01-01

    We investigate, using the modeling code SHAPE, the three-dimensional structure of the bipolar Homunculus nebula surrounding Eta Carinae, as mapped by new ESO VLT/X-Shooter observations of the H2 $\\lambda=2.12125$ micron emission line. Our results reveal for the first time important deviations from the axisymmetric bipolar morphology: 1) circumpolar trenches in each lobe positioned point-symmetrically from the center and 2) off-planar protrusions in the equatorial region from each lobe at longitudinal (~55 degrees) and latitudinal (10-20 degrees) distances from the projected apastron direction of the binary orbit. The angular distance between the protrusions (~110 degrees) is similar to the angular extent of each polar trench (~130 degrees) and nearly equal to the opening angle of the wind-wind collision cavity (~110 degrees). As in previous studies, we confirm a hole near the centre of each polar lobe and no detectable near-IR H2 emission from the thin optical skirt seen prominently in visible imagery. We con...

  16. Astrophysical jets and outflows

    Science.gov (United States)

    de Gouveia Dal Pino, Elisabete M.

    Highly collimated supersonic jets and less collimated outflows are observed to emerge from a wide variety of astrophysical objects. They are seen in young stellar objects (YSOs), proto-planetary nebulae, compact objects (like galactic black holes or microquasars, and X-ray binary stars), and in the nuclei of active galaxies (AGNs). Despite their different physical scales (in size, velocity, and amount of energy transported), they have strong morphological similarities. What physics do they share? These systems are either hydrodynamic or magnetohydrodynamic (MHD) in nature and are, as such, governed by non-linear equations. While theoretical models helped us to understand the basic physics of these objects, numerical simulations have been allowing us to go beyond the one-dimensional, steady-state approach extracting vital information. In this lecture, the formation, structure, and evolution of the jets are reviewed with the help of observational information, MHD and purely hydrodynamical modeling, and numerical simulations. Possible applications of the models particularly to YSOs and AGN jets are addressed.

  17. A 3D view of the outflow in the Orion Molecular Cloud 1 (OMC-1)

    DEFF Research Database (Denmark)

    Nissen, H.D.; Cunningham, N.J.; Sherson, Maiken Gustafsson;

    2012-01-01

    The fast outflow emerging from a region associated with massive star formation in the Orion Molecular Cloud 1 (OMC-1), located behind the Orion Nebula, appears to have been set in motion by an explosive event. Here we study the structure and dynamics of outflows in OMC-1. We combine radial velocity...

  18. Pulsar Wind Nebulae Modeling

    CERN Document Server

    Bucciantini, N

    2013-01-01

    Pulsar Wind Nebulae (PWNe) are ideal astrophysical laboratories where high energy relativistic phenomena can be investigated. They are close, well resolved in our observations, and the knowledge derived in their study has a strong impact in many other fields, from AGNs to GRBs. Yet there are still unresolved issues, that prevent us from a full clear understanding of these objects. The lucky combination of high resolution X-ray imaging and numerical codes to handle the outflow and dynamical properties of relativistic MHD, has opened a new avenue of investigation that has lead to interesting progresses in the last years. Despite all of this, we do not understand yet how particles are accelerated, and the functioning of the pulsar wind and pulsar magnetosphere, that power PWNe. I will review what is now commonly known as the MHD paradigm, and in particular I will focus on various approaches that have been and are currently used to model these systems. For each I will highlight its advantages, limitations, and de...

  19. He II λ4686 in η Carinae

    DEFF Research Database (Denmark)

    Teodoro, M.; Damineli, A.; Arias, J.I.;

    2012-01-01

    The periodic spectroscopic events in eta Carinae are now well established and occur near the periastron passage of two massive stars in a very eccentric orbit. Several mechanisms have been proposed to explain the variations of different spectral features, such as an eclipse by the wind-wind colli...

  20. Superluminous Supernovae: No Threat from Eta Carinae

    Science.gov (United States)

    Thomas, Brian; Melott, A. L.; Fields, B. D.; Anthony-Twarog, B. J.

    2008-05-01

    Recently Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of 1044 Joules. It was proposed that the progenitor may have been a massive evolved star similar to η Carinae, which resides in our own galaxy at a distance of about 2.3 kpc. η Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given its rotation axis is unlikely to produce a Gamma-Ray Burst oriented toward the Earth, η Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We find that given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over 104 y, and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovae, endocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered "dangerous” for other reasons. However, due to reddening and extinction by the interstellar medium, η Carinae is unlikely to trigger such effects to any significant degree.

  1. Gravitational fragmentation of the Carina Flare supershell

    Science.gov (United States)

    Wünsch, Richard

    2015-03-01

    We study the gravitational fragmentation of a thick shell comparing the analytical theory to 3D hydrodynamic simulations and to observations of the Carina Flare supershell. We use both grid-based (AMR) and particle-based (SPH) codes to follow the idealised model of the fragmenting shell and found an excellent agreement between the two codes. Growth rates of fragments at different wavelength are well described by the pressure assisted gravitational instability (PAGI) - a new theory of the thick shell fragmentation. Using the APEX telescope we observe a part of the surface of the Carina Flare supershell (GSH287+04-17) in the 13CO(2-1) line. We apply a new clump-finding algorithm DENDROFIND to identify 50 clumps. We determine the clump mass function and we construct the minimum spanning tree connecting clumps positions to estimate the typical distance among clumps. We conclude that the observed masses and distances correspond well to the prediction of PAGI.

  2. Bipolar outflows in OH/IR stars

    CERN Document Server

    Zijlstra, A A; Hekkert, P L; Likkel, L; Comeron, F; Norris, R P; Molster, F J; Cohen, R J; Zijlstra, Albert A.

    2000-01-01

    We investigate the development of bipolar outflows during the early post-AGB evolution. A sample of ten OH/IR stars is observed at high angular resolution, including bipolar nebulae (OH231.8+4.2), bright post-AGB stars (HD 101584) and reflection nebulae (e.g. Roberts 22). The IRAS colour--colour diagram separates the sample into different types of objects. One group may contain the progenitors to the (few) extreme bipolar planetary nebulae. Two objects show colours and chemistry very similar to the planetary nebulae with late IR-[WC] stars. One object is a confirmed close binary. A model is presented consisting of an outer AGB wind which is swept up by a faster post-AGB wind, with either wind being non-spherically symetric. The interface of the two winds is shown to exhibit a linear relation between velocity and distance from the star. The OH data confirms the predicted linear velocity gradients, and reveals torus-like, uniformly expanding components. All sources are discussed in detail using optical/HST imag...

  3. Superluminous supernovae: No threat from Eta Carinae

    CERN Document Server

    Thomas, Brian C; Fields, Brian D; Anthony-Twarog, Barbara J

    2007-01-01

    Recently Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of ~10^44 Joules. It was proposed that the progenitor may have been a massive evolved star similar to Eta Carinae, which resides in our own galaxy at a (poorly determined) distance of ~2.5 kpc. Eta Carinae appears ready to detonate, and in fact had an outburst in 1843. Although it is too distant to pose a serious threat as a normal supernova, and given its rotation axis is unlikely to produce a Gamma Ray Burst oriented toward the Earth, Eta Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We find that given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over ~10^4 y, and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possib...

  4. Double Engine for a Nebula

    Science.gov (United States)

    2009-08-01

    ESO has just released a stunning new image of a field of stars towards the constellation of Carina (the Keel). This striking view is ablaze with a flurry of stars of all colours and brightnesses, some of which are seen against a backdrop of clouds of dust and gas. One unusual star in the middle, HD 87643, has been extensively studied with several ESO telescopes, including the Very Large Telescope Interferometer (VLTI). Surrounded by a complex, extended nebula that is the result of previous violent ejections, the star has been shown to have a companion. Interactions in this double system, surrounded by a dusty disc, may be the engine fuelling the star's remarkable nebula. The new image, showing a very rich field of stars towards the Carina arm of the Milky Way, is centred on the star HD 87643, a member of the exotic class of B[e] stars [1]. It is part of a set of observations that provide astronomers with the best ever picture of a B[e] star. The image was obtained with the Wide Field Imager (WFI) attached to the MPG/ESO 2.2-metre telescope at the 2400-metre-high La Silla Observatory in Chile. The image shows beautifully the extended nebula of gas and dust that reflects the light from the star. The central star's wind appears to have shaped the nebula, leaving bright, ragged tendrils of gas and dust. A careful investigation of these features seems to indicate that there are regular ejections of matter from the star every 15 to 50 years. A team of astronomers, led by Florentin Millour, has studied the star HD 87643 in great detail, using several of ESO's telescopes. Apart from the WFI, the team also used ESO's Very Large Telescope (VLT) at Paranal. At the VLT, the astronomers used the NACO adaptive optics instrument, allowing them to obtain an image of the star free from the blurring effect of the atmosphere. To probe the object further, the team then obtained an image with the Very Large Telescope Interferometer (VLTI). The sheer range of this set of observations

  5. Unveiling shocks in planetary nebulae

    CERN Document Server

    Guerrero, M A; Medina, J J; Luridiana, V; Miranda, L F; Riera, A; Velázquez, P F

    2013-01-01

    The propagation of a shock wave into a medium is expected to heat the material beyond the shock, producing noticeable effects in intensity line ratios such as [O III]/Halpha. To investigate the occurrence of shocks in planetary nebulae (PNe), we have used all narrowband [O III] and Halpha images of PNe available in the HST archive to build their [O III]/Halpha ratio maps and to search for regions where this ratio is enhanced. Regions with enhanced [O III]/Halpha emission ratio can be ascribed to two different types of morphological structures: bow-shock structures produced by fast collimated outflows and thin skins enveloping expanding nebular shells. Both collimated outflows and expanding shells are therefore confirmed to generate shocks in PNe. We also find regions with depressed values of the [O III]/Halpha ratio which are found mostly around density bounded PNe, where the local contribution of [N II] emission into the F656N Halpha filter cannot be neglected.

  6. A Survey of Irradiated Pillars, Globules, and Jets in the Carina Nebul

    CERN Document Server

    Hartigan, P; Smith, N; Bally, J

    2015-01-01

    We present wide-field, deep narrowband H$_2$, Br$\\gamma$, H$\\alpha$, [S II], [O III], and broadband I and K-band images of the Carina star formation region. The new images provide a large-scale overview of all the H$_2$ and Br$\\gamma$ emission present in over a square degree centered on this signature star forming complex. By comparing these images with archival HST and Spitzer images we observe how intense UV radiation from O and B stars affects star formation in molecular clouds. We use the images to locate new candidate outflows and identify the principal shock waves and irradiated interfaces within dozens of distinct areas of star-forming activity. Shocked molecular gas in jets traces the parts of the flow that are most shielded from the intense UV radiation. Combining the H$_2$ and optical images gives a more complete view of the jets, which are sometimes only visible in H$_2$. The Carina region hosts several compact young clusters, and the gas within these clusters is affected by radiation from both the...

  7. Exploring the multifaceted circumstellar environment of the luminous blue variable HR Carinae

    Science.gov (United States)

    Buemi, C. S.; Trigilio, C.; Leto, P.; Umana, G.; Ingallinera, A.; Cavallaro, F.; Cerrigone, L.; Agliozzo, C.; Bufano, F.; Riggi, S.; Molinari, S.; Schillirò, F.

    2017-03-01

    We present a multiwavelength study of the Galactic luminous blue variable HR Carinae, based on new high-resolution mid-infrared (IR) and radio images obtained with the Very Large Telescope (VLT) and the Australia Telescope Compact Array (ATCA), which have been complemented by far-infrared Herschel-Photodetector Array Camera and Spectrometer (PACS) observations and ATCA archive data. The Herschel images reveal the large-scale distribution of the dusty emitting nebula, which extends mainly to the north-east direction, up to 70 arcsec from the central star, and is oriented along the direction of the space motion of the star. In the mid-infrared images, the brightness distribution is characterized by two arc-shaped structures, tracing an inner envelope surrounding the central star more closely. At radio wavelengths, the ionized gas emission lies on the opposite side of the cold dust with respect to the position of the star, as if the ionized front were confined by the surrounding medium in the north-south direction. Comparison with previous data indicates significant changes in the radio nebula morphology and in the mass-loss rate from the central star, which has increased from 6.1 × 10-6 M⊙ yr-1 in 1994-1995 to 1.17 × 10-5 M⊙ yr-1 in 2014. We investigate possible scenarios that could have generated the complex circumstellar environment revealed by our multiwavelength data.

  8. η Carinae Baby Homunculus uncovered by ALMA

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, Zulema; Beaklini, Pedro P. B. [Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, R. do Matão 1226, Cidade Universitária, CEP 05508-900 São Paulo, SP (Brazil); Falceta-Gonçalves, Diego, E-mail: zulema.abraham@iag.usp.br [Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, R. Arlindo Bettio 1000, 03828-000 São Paulo, SP (Brazil)

    2014-08-20

    We report observations of η Carinae obtained with ALMA in the continuum of 100, 230, 280, and 660 GHz in 2012 November, with a resolution that varied from 2.''88 to 0.''45 for the lower and higher frequencies, respectively. The source is not resolved, even at the highest frequency; its spectrum is characteristic of thermal bremsstrahlung of a compact source, but different from the spectrum of optically thin wind. The recombination lines H42α, He42α, H40α, He40α, H50β, H28α, He28α, H21α, and He21α were also detected, and their intensities reveal non-local thermodynamic equilibrium effects. We found that the line profiles could only be fit by an expanding shell of dense and ionized gas, which produces a slow shock in the surroundings of η Carinae. Combined with fittings to the continuum, we were able to constrain the shell size, radius, density, temperature, and velocity. The detection of the He recombination lines is compatible with the high-temperature gas and requires a high-energy ionizing photon flux, which must be provided by the companion star. The mass-loss rate and wind velocity, necessary to explain the formation of the shell, are compatible with an luminous blue variable eruption. The position, velocity, and physical parameters of the shell coincide with those of the Weigelt blobs. The dynamics found for the expanding shell correspond to matter ejected by η Carinae in 1941 in an event similar to that which formed the Little Homunculus; for that reason, we called the new ejecta the 'Baby Homunculus'.

  9. $\\eta$ Carinae Baby Homunculus Uncovered by ALMA

    CERN Document Server

    Abraham, Zulema; Beaklini, Pedro P B

    2014-01-01

    We report observations of $\\eta$ Carinae obtained with ALMA in the continuum of 100, 230, 280 and 660 GHz in 2012 November, with a resolution that varied from 2.88" to 0.45" for the lower and higher frequencies respectively. The source is not resolved, even at the highest frequency; its spectrum is characteristic of thermal bremsstrahlung of a compact source, but different from the spectrum of optically thin wind. The recombination lines H42$\\alpha$, He42$\\alpha$, H40$\\alpha$, He40$\\alpha$, H50$\\beta$, H28$\\alpha$, He28$\\alpha$, H21$\\alpha$ and He21$\\alpha$ were also detected and their intensities reveal non local thermodynamic equilibrium (NLTE) effects. We found that the line profiles could only be fit by an expanding shell of dense and ionized gas, which produces a slow shock in the surroundings of $\\eta$ Carinae. Combined with fittings to the continuum, we were able to constrain the shell size, radius, density, temperature and velocity. The detection of the He recombination lines is compatible with the hi...

  10. The Ultraviolet Spectrum of η Carinae: Investigation of the Ejecta Absorption

    Science.gov (United States)

    Nielsen, K. E.; Gull, T. R.; Vieira Kober, G.

    2005-03-01

    We have investigated the far- through mid-UV (1150-2360 Å) spectrum of η Carinae during the late stages of its broad maximum using the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) moderate dispersion echelle modes. The η Car spectrum is a mixture of absorption and emission lines from the surrounding nebula superimposed on broad stellar wind features. This paper provides a description of the observed spectrum including the wind features, the interstellar absorption, and the emission spectrum from the surrounding nebula, but with the emphasis on the absorption spectrum formed in the foreground ejecta. The ejecta absorption spectrum has a complicated velocity structure in which two velocity structures, at -146 and -513 km s-1, are easily distinguished. These two velocity components, formed in different regions of the η Car nebula, have in an earlier analysis been identified and demonstrated to have very different spectral characteristics. The slower velocity component is time variable over the spectroscopic period and is characterized by spectral lines from mainly singly ionized iron-peak elements, while the faster one shows transitions from neutral and singly ionized elements in addition to molecular lines from the hydrogen Lyman bands. The high-velocity H2 lines dominate great parts of the spectrum with over 800 identified transitions from energy levels up to 30,000 cm-1. The STIS MAMA data provide the tool for spatial investigations of the central parts of η Car. H I Lyα pumped and semiforbidden emission lines are observed to be formed east of the central source toward Weigelt blobs B and C, located up to 0.2" from the central source. The complete spectrum, with nebular and interstellar line identifications, is available in the electronic edition of the paper. Laboratory for Astronomy and Solar Physics, Code 681, Goddard Space Flight Center, Greenbelt, MD 20771.

  11. Multiple Fast Molecular Outflows in the PPN CRL 618

    CERN Document Server

    Lee, Chin-Fei; Contreras, Carmen Sánchez; Huang, Po-Sheng; Tay, Jeremy Jian Hao

    2013-01-01

    CRL 618 is a well-studied pre-planetary nebula. It has multiple highly collimated optical lobes, fast molecular outflows along the optical lobes, and an extended molecular envelope that consists of a dense torus in the equator and a tenuous round halo. Here we present our observations of this source in CO J=3-2 and HCN J=4-3 obtained with the Submillimeter Array at up to ~ 0.3" resolutions. We spatially resolve the fast molecular-outflow region previously detected in CO near the central star and find it to be composed of multiple outflows that have similar dynamical ages, and are oriented along the different optical lobes. We also detect fast molecular outflows further away from the central star near the tips of the extended optical lobes and a pair of equatorial outflows inside the dense torus. We find that two episodes of bullet ejections in different directions are needed, one producing the fast molecular outflows near the central star, and one producing the fast molecular outflows near the tips of the ext...

  12. The filamentary Multi-Polar Planetary Nebula NGC 5189

    CERN Document Server

    Sabin, L; López, J A; García-Díaz, Ma T; Ramos-Larios, G

    2012-01-01

    We present a set of optical and infrared images combined with long-slit, medium and high dispersion spectra of the southern planetary nebula (PN) NGC 5189. The complex morphology of this PN is puzzling and has not been studied in detail so far. Our investigation reveals the presence of a new dense and cold infrared torus (alongside the optical one) which probably generated one of the two optically seen bipolar outflows and which might be responsible for the twisted appearance of the optical torus via an interaction process. The high-resolution MES-AAT spectra clearly show the presence of filamentary and knotty structures as well as three expanding bubbles. Our findings therefore suggest that NGC 5189 is a quadrupolar nebula with multiple sets of symmetrical condensations in which the interaction of outflows has determined the complex morphology.

  13. THE FILAMENTARY MULTI-POLAR PLANETARY NEBULA NGC5189

    Directory of Open Access Journals (Sweden)

    L. Sabin

    2012-01-01

    Full Text Available We present a set of optical and infrared images combined with long-slit, medium and high dispersion spectra of the southern planetary nebula (PN NGC5189. The complex morphology of this PN is puzzling and has not been studied in detailed so far. Our investigation reveals the presence of a new dense and cold infrared torus (alongside the optical one which probably generated one of the two optically seen bipolar outflows and which might be responsible for the twisted appearance of the optical torus via an interaction process. The high-resolution MES-AAT spectra clearly show the presence of filamentary and knotty structures as well as three expanding bubbles. Our findings therefore suggest that NGC5189 is a quadrupolar nebula with multiple sets of symmetrical condensations in which the interaction of outflows has determined its complex morphology.

  14. Outflows, jets and shocks in the orion nebula

    Directory of Open Access Journals (Sweden)

    C. R. O`Dell

    2000-01-01

    Full Text Available El c umulo de estrellas j ovenes asociadas a la Nebulosa de Ori on es un buen laboratorio para el estudio de los plasmas. Vemos cinco tipos de ujos y choques. Los ujos de foto-ablaci on de los proplyds m as cercanos a 1Ori C forman choques cuasi estacionarios con el viento de la estrella. Se observan micro-chorros con escalas menores a 103 AU en 20 estrellas peque~nas. Los chorros aislados, con altas velocidades y escalas cercanas a 104 AU, son comunes pero menos numerosos. Tambi en se ven choques cuando los chorros golpean al gas nebular ionizado o al gas neutro del fondo. El tipo de objeto nal es el choque estacionario formado por la interacci on del viento estelar, generado durante la formaci on del disco, con el gas ambiental que uye hacia afuera de la nebulosa.

  15. Pulsar Wind Nebulae as Cosmic Pevatrons: A Current Sheet's Tale

    CERN Document Server

    Arons, Jonathan

    2012-01-01

    I outline, from a theoretical and somewhat personal perspective, significant features of Pulsar Wind Nebulae as Cosmic Accelerators. I discuss recent studies of Pulsar Wind Nebulae (PWNe). I pay special attention to the recently discovered gamma ray flares in the Crab Nebula's emission, focusing on the possibility, raised by the observations, that the accelerating electric field exceeds the magnetic field, suggesting that reconnection in the persistent current layer (a current sheet) plays a significant role in the behavior of this well studied Pevatron. I address the present status of the termination shock model for the particle accelerator that converts the wind flow energy to the observed non thermal particle spectra, concluding that it has a number of major difficulties related to the transverse magnetic geometry of the shock wave. I discuss recent work on the inferred pair outflow rates, which are in excess of those predicted by existing theories of pair creation, and use those results to point out that ...

  16. A disc in the heart of the Ant nebula

    CERN Document Server

    Lykou, Foteini; Lagadec, Eric; Zijlstra, Albert

    2007-01-01

    We present the discovery of a silicate disc at the centre of the planetary nebula Mz3 (the Ant). The nebula was observed with MIDI on the Very Large Telescope Interferometer (VLTI). The visibilities obtained at different orientations clearly indicate the presence of a dusty, nearly edge-on disc in the heart of the nebula. An amorphous silicate absorption feature is clearly seen in our mid-IR spectrum and visibility curves. We used radiative transfer Monte Carlo simulations to constrain the geometrical and physical parameters of the disc. We derive an inner radius of 9 AU (~6mas assuming D=1.4kpc). This disc is perpendicular to, but a factor of 10^{3} smaller than the optical bipolar outflow.

  17. GIANT Hα NEBULA SURROUNDING THE STARBURST MERGER NGC 6240

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Michitoshi [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Yagi, Masafumi; Komiyama, Yutaka; Kashikawa, Nobunari [Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Ohyama, Youichi [Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, AS/NTU No.1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan, R.O.C. (China); Tanaka, Hisashi [Department of Physical Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Okamura, Sadanori, E-mail: yoshidam@hiroshima-u.ac.jp [Department of Advanced Sciences, Faculty of Science and Engineering, Hosei University, Koganei, Tokyo 184-8584 (Japan)

    2016-03-20

    We revealed the detailed structure of a vastly extended Hα-emitting nebula (“Hα nebula”) surrounding the starburst/merging galaxy NGC 6240 by deep narrow-band imaging observations with the Subaru Suprime-Cam. The extent of the nebula is ∼90 kpc in diameter and the total Hα luminosity amounts to L{sub Hα} ≈ 1.6 × 10{sup 42} erg s{sup −1}. The volume filling factor and the mass of the warm ionized gas are ∼10{sup −4}–10{sup −5} and ∼5 × 10{sup 8} M{sub ⊙}, respectively. The nebula has a complicated structure, which includes numerous filaments, loops, bubbles, and knots. We found that there is a tight spatial correlation between the Hα nebula and the extended soft-X-ray-emitting gas, both in large and small scales. The overall morphology of the nebula is dominated by filamentary structures radially extending from the center of the galaxy. A large-scale bipolar bubble extends along the minor axis of the main stellar disk. The morphology strongly suggests that the nebula was formed by intense outflows—superwinds—driven by starbursts. We also found three bright knots embedded in a looped filament of ionized gas that show head-tail morphologies in both emission-line and continuum, suggesting close interactions between the outflows and star-forming regions. Based on the morphology and surface brightness distribution of the Hα nebula, we propose the scenario that three major episodes of starburst/superwind activities, which were initiated ∼10{sup 2} Myr ago, formed the extended ionized gas nebula of NGC 6240.

  18. Kinematics, turbulence and evolution of planetary nebulae

    CERN Document Server

    Gesicki, K; Zijlstra, A A; Gesicki, Krzysztof; Acker, Agnes; Zijlstra, Albert A.

    2003-01-01

    This paper discusses the location of a sample of planetary nebulae on the HR diagram. We determine the internal velocity fields of 14 planetary nebulae from high-resolution echelle spectroscopy, with the help of photoionization models. The mass averaged velocity is shown to be a robust, simple parameter describing the outflow. The expansion velocity and radius are used to define the dynamical age; together with the stellar temperature, this gives a measurement of the luminosity and core mass of the central star. The same technique is applied to other planetary nebulae with previously measured expansion velocities, giving a total sample of 73 objects. The objects cluster closely around the Schoenberner track of 0.61 M_sun, with a very narrow distribution of core masses. The masses are higher than found for local white dwarfs. The luminosities determined in this way tend to be higher by a factor of a few than those derived from the nebular luminosities. The discrepancy is highest for the hottest (most evolved) ...

  19. CARINA oxygen data in the Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    I. Stendardo

    2009-12-01

    Full Text Available In the CARINA (Carbon dioxide in the Atlantic Ocean project, a new dataset with many previously unpublished hydrographic data from the Atlantic, Arctic and Southern Ocean was assembled and subjected to careful quality control (QC procedures. Here, we present the dissolved oxygen measurements in the Atlantic region of the dataset and describe in detail the secondary QC procedures that aim to ensure that the data are internally consistent. This is achieved by a cross-over analysis, i.e. the comparison of deep ocean data at places that were sampled by different cruises at different times. Initial adjustments to the individual cruises were then determined by an inverse procedure that computes a set of adjustments that requires the minimum amount of adjustment and at the same time reduces the offsets in an optimal manner. The initial adjustments were then reviewed by the CARINA members, and only those that passed the following two criteria were adopted: (i the region is not subject to substantial temporal variability, and (ii the adjustment must be based on at least three stations from each cruise. No adjustment was recommended for cruises that did not fit these criteria. The final CARINA-Oxygen dataset has 103414 oxygen samples from 9491 stations obtained during 98 cruises covering three decades. The sampling density of the oxygen data is particularly good in the North Atlantic north of about 40° N especially after 1987. In contrast, the sample density in the South Atlantic is much lower. Some cruises appear to have poor data quality, and were subsequently omitted from the adjusted dataset. Of the data included in the adjusted dataset, 20% were adjusted with a mean adjustment of 2%. Due to the achieved internal consistency, the resulting product is well suited to produce an improved climatology or to study long-term changes in the oxygen content of the ocean. However, the adjusted dataset is not necessarily better suited than the unadjusted data to

  20. Modelling the Central Constant Emission X-ray component of η Carinae

    Science.gov (United States)

    Russell, Christopher M. P.; Corcoran, Michael F.; Hamaguchi, Kenji; Madura, Thomas I.; Owocki, Stanley P.; Hillier, D. John

    2016-05-01

    The X-ray emission of η Carinae shows multiple features at various spatial and temporal scales. The central constant emission (CCE) component is centred on the binary and arises from spatial scales much smaller than the bipolar Homunculus nebula, but likely larger than the central wind-wind collision region between the stars as it does not vary over the ˜2-3 month X-ray minimum when it can be observed. Using large-scale 3D smoothed particle hydrodynamics (SPH) simulations, we model both the colliding-wind region between the stars, and the region where the secondary wind collides with primary wind ejected from the previous periastron passage. The simulations extend out to one hundred semimajor axes and make two limiting assumptions (strong coupling and no coupling) about the influence of the primary radiation field on the secondary wind. We perform 3D radiative transfer calculations on the SPH output to synthesize the X-ray emission, with the aim of reproducing the CCE spectrum. For the preferred primary mass-loss rate dot{M}_A≈ 8.5× 10^{-4} M_{⊙} yr-1, the model spectra well reproduce the observation as the strong- and no-coupling spectra bound the CCE observation for longitude of periastron ω ≈ 252°, and bound/converge on the observation for ω ≈ 90°. This suggests that η Carinae has moderate coupling between the primary radiation and secondary wind, that both the region between the stars and the comoving collision on the backside of the secondary generate the CCE, and that the CCE cannot place constraints on the binary's line of sight. We also discuss comparisons with common X-ray fitting parameters.

  1. Molecules in Bipolar Outflows

    CERN Document Server

    Tafalla, Mario

    2012-01-01

    Bipolar outflows constitute some of the best laboratories to study shock chemistry in the interstellar medium. A number of molecular species have their abundance enhanced by several orders of magnitude in the outflow gas, likely as a combined result of dust mantle disruption and high temperature gas chemistry, and therefore become sensitive indicators of the physical changes taking place in the shock. Identifying these species and understanding their chemical behavior is therefore of high interest both to chemical studies and to our understanding of the star-formation process. Here we review some of the recent progress in the study of the molecular composition of bipolar outflows, with emphasis in the tracers most relevant for shock chemistry. As we discuss, there has been rapid progress both in characterizing the molecular composition of certain outflows as well as in modeling the chemical processes likely involved. However, a number of limitations still affect our understanding of outflow chemistry. These i...

  2. Chandra Observations of Outflows from PSR J1509-5850

    CERN Document Server

    Klingler, Noel; Rangelov, Blagoy; Pavlov, George G; Posselt, Bettina; Ng, C -Y

    2016-01-01

    PSR J1509-5850 is a middle-aged pulsar with the period P ~ 89 ms, spin-down power Edot = 5.1 x 10^35 erg/s, at a distance of about 3.8 kpc. We report on deep Chandra X-ray Observatory observations of this pulsar and its pulsar wind nebula (PWN). In addition to the previously detected tail extending up to 7' southwest from the pulsar (the southern outflow), the deep images reveal a similarly long, faint diffuse emission stretched toward the north (the northern outflow) and the fine structure of the compact nebula (CN) in the pulsar vicinity. The CN is resolved into two lateral tails and one axial tail pointing southwest (a morphology remarkably similar to that of the Geminga PWN), which supports the assumption that the pulsar moves towards the northeast. The luminosities of the southern and northern outflows are about 1 x 10^33 and 4 x 10^32 erg/s, respectively. The spectra extracted from four regions of the southern outflow do not show any softening with increasing distance from the pulsar. The lack of synchr...

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

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, R. [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Vlemmings, W. H. T. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Huggins, P. J. [Physics Department, New York University, 4 Washington Place, New York, NY 10003 (United States); Nyman, L.-Å. [Joint ALMA Observatory (JAO), Alonso de Cordova 3107, Vitacura, Santiago de Chile (Chile); Gonidakis, I., E-mail: raghvendra.sahai@jpl.nasa.gov [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Marsfield NSW 2122 (Australia)

    2013-11-10

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

  4. ALMA Observations of the Coldest Place in the Universe: The Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W. H. T.; Huggins, P. J.; Nyman, L.-Å.; Gonidakis, I.

    2013-11-01

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

  5. Atlantic Ocean CARINA data: overview and salinity adjustments

    Energy Technology Data Exchange (ETDEWEB)

    Tanhua, T. [IFM-GEOMAR, Leibniz Institute for Marine Sciences, Chemical Oceanography, Kiel, Germany; Steinfeldt, R. [University of Bremen, Bremen, Germany; Key, Robert [Princeton University; Brown, P. [University of East Anglia, Norwich, United Kingdom; Gruber, N. [ETH Zurich, Switzerland; Wanninkhof, R. [Atlantic Oceanographic & Meteorological Laboratory, NOAA; Perez, F.F. [Instituto de Investigaciones Marinas de Vigo, CSIC, Vigo, Spain; Kortzinger, A. [IFM-GEOMAR, Leibniz Institute for Marine Sciences, Chemical Oceanography, Kiel, Germany; Velo, A. [Instituto de Investigaciones Marinas de Vigo, CSIC, Vigo, Spain; Schuster, U. [University of East Anglia, Norwich, United Kingdom; Van Heuven, S. [University of Groningen, The Netherlands; Bullister, J.L. [NOAA Pacific Marine Environmental Laboratory; Stendardo, I. [ETH Zurich, Switzerland; Hoppema, M. [Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany; Olsen, Are [Bjerknes Centre for Climate Research, UNIFOB AS, Bergen, Norway; Kozyr, Alexander [ORNL; Pierrot, D. [Cooperative Institute of Marine and Atmospheric Sciences, U. Miami; Schirnick, C. [IFM-GEOMAR, Leibniz Institute for Marine Sciences, Chemical Oceanography, Kiel, Germany; Wallace, D.W.R. [IFM-GEOMAR, Leibniz Institute for Marine Sciences, Chemical Oceanography, Kiel, Germany

    2010-01-01

    Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruise data sets in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon dioxide IN the Atlantic Ocean). The data have gone through rigorous quality control procedures to assure the highest possible quality and consistency. The data for the pertinent parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the three data products: merged data files with measured, calculated and interpolated data for each of the three CARINA regions, i.e. the Arctic Mediterranean Seas, the Atlantic and the Southern Ocean. These products have been corrected to be internally consistent. Ninety-eight of the cruises in the CARINA database were conducted in the Atlantic Ocean, defined here as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30 S. Here we present an overview of the Atlantic Ocean synthesis of the CARINA data and the adjustments that were applied to the data product. We also report the details of the secondary QC (Quality Control) for salinity for this data set. Procedures of quality control including crossover analysis between stations and inversion analysis of all crossover data are briefly described. Adjustments to salinity measurements were applied to the data from 10 cruises in the Atlantic Ocean region. Based on our analysis we estimate the internal consistency of the CARINA-ATL salinity data to be 4.1 ppm. With these adjustments the CARINA data products are consistent both internally was well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, oceanic carbon inventories

  6. Cool gaseous nebulae

    CERN Document Server

    Shaver, P A; Pottasch, S R

    1979-01-01

    The electron temperatures of diffuse gaseous nebulae have long been thought to be close to 10/sup 4/K. Much lower temperatures were derived from some of the early radio continuum and recombination line work, but these were generally considered to be wrong for a variety of reasons. While there is little doubt that the bright nebulae do indeed have temperatures of approximately 8000-9000K, there are strong indications that some nebulae of lower densities have much lower temperatures, nebulae were made in order to determine electron temperatures in the absence of such effects as collisional de-excitation, stimulated emission, and pressure broadening. Several of these nebulae have been found to have temperatures below 5000K and for two of them which are discussed (RCW94 and G339.1-0.2) absolute upper limits of approximately 4700 K are imposed by the line widths alone. (11 refs).

  7. The variable Crab Nebula

    CERN Document Server

    Tavani, Marco

    2011-01-01

    The remarkable Crab Nebula is powered by an energetic pulsar whose relativistic wind interacts with the inner parts of the Supernova Remnant SN1054. Despite low-intensity optical and X-ray variations in the inner Nebula, the Crab has been considered until now substantially stable at X-ray and gamma-ray energies. This paradigm has been shattered by the AGILE discovery in September 2010 of a very intense transient gamma-ray flare of nebular origin. For the first time, the Crab Nebula was "caught in the act" of accelerating particles up to 10^15 eV within the shortest timescale ever observed in a cosmic nebula (1 day or less). Emission between 50 MeV and a few GeV was detected with a quite hard spectrum within a short timescale. Additional analysis and recent Crab Nebula data lead to identify a total of four major flaring gamma-ray episodes detected by AGILE and Fermi during the period mid-2007/mid-2011. These observations challenge emission models of the pulsar wind interaction and particle acceleration process...

  8. Clown Face Nebula (NGC 2392)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    A planetary nebula, also known as the Eskimo Nebula, in the constellation Gemini, position RA 07 h 29.2 m, dec. +20° 55'. It is bluish, 13'' in diameter, and of ninth magnitude, with a tenth-magnitude central star. The blue-green nebula's hazy outer regions are thought to resemble an Eskimo's hood or clown's ruff....

  9. High Spatial/Spectral Resolution Studies of Eta Carinae

    Science.gov (United States)

    Gull, Theodore R.; Eta Carinae HST Treasury Team

    2005-01-01

    The ejecta of Eta Carinae revealed by HST/STIS are in a large range of physical conditions. As Eta Carinae undergoes a 5.52 period changes occur in nebular emission and nebular absorption. ""Warm"" neutral regions partially ionized regions and fully ionized regions undergo significant changes. Over 2000 emission lines most of Fe-like elements have been indentified in the Weigelt blobs B and D. Over 500 emission lines have been identifed in the Strontium Filament. An ionized Little Homunculus is nestled within the neutral-shelled Homunculus. In line of sight over 500 nebular absorption lines have been identified with up to twenty velocity components. STIS is following changes in many nebular emission and absorption lines as Eta Carinae approaches the minimum predicted to be in June/July 2003 during the General Assembly. Coordinated observations with HST CHANDRA RXTE FUSE UVES/VLT Gemini and other observatories are following this minimum.

  10. Is the Ejecta of ETA Carinae Overabundant or Overexcited

    Science.gov (United States)

    Gull, Theodore; Davidson, Kris; Johansson, Sveneric; Damineli, Augusto; Ishibashi, Kaxunori; Corcoran, Michael; Hartman, Henrick; Viera, Gladys; Nielsen, Krister

    2003-01-01

    The ejecta of Eta Carinae, revealed by HST/STIS, are in a large range of physical conditions. As Eta Carinae undergoes a 5.52 period, changes occur in nebular emission and nebular absorption. "Warm" neutral regions, partially ionized regions, and fully ionized regions undergo significant changes. Over 2000 emission lines, most of Fe-like elements, have been indentified in the Weigelt blobs B and D. Over 500 emission lines have been indentified in the Strontium Filament. An ionized Little Homunculus is nestled within the neutral-shelled Homunculus. In line of sight, over 500 nebular absorption lines have been identified with up to twenty velocity components. STIS is following changes in many nebular emission and absorption lines as Eta Carinae approaches the minimum, predicted to be in June/July 2003, during the General Assembly. Coordinated observations with HST, CHANDRA, RXTE, FUSE, UVES/VLT, Gemini and other observatories are following this minimum.

  11. Is the Ejecta of Eta Carinae Overabundant or Overexcited?

    Science.gov (United States)

    Gull, Theodore; Davidson, Kris; Johansson, Sveneric; Damineli, Augusto; Ishibashi, Kazunori; Corcoran, Michael; Hartman, Henrick; Viera, Gladys; Nielsen, Krister; Eta Carinae Teams

    The ejecta of Eta Carinae revealed by HST/STIS are in a large range of physical conditions. As Eta Carinae undergoes a 5.52 period changes occur in nebular emission and nebular absorption. ""Warm"" neutral regions partially ionized regions and fully ionized regions undergo significant changes. Over 2000 emission lines most of Fe-like elements have been indentified in the Weigelt blobs B and D. Over 500 emission lines have been identifed in the Strontium Filament. An ionized Little Homunculus is nestled within the neutral-shelled Homunculus. In line of sight over 500 nebular absorption lines have been identified with up to twenty velocity components. STIS is following changes in many nebular emission and absorption lines as Eta Carinae approaches the minimum predicted to be in June/July 2003 during the General Assembly. Coordinated observations with HST CHANDRA RXTE FUSE UVES/VLT Gemini and other observatories are following this minimum.

  12. The periodicity of the eta Carinae events

    CERN Document Server

    Damineli, A; Hillier, D J; Stahl, O; Levenhagen, R S; Leister, N V; Groh, J H; Teodoro, M; Colombo, J F Albacete; Gonzalez, F; Arias, J; Levato, H; Grosso, M; Morrell, N; Gamen, R; Wallerstein, G; Niemela, V

    2007-01-01

    Extensive spectral observations of eta Carinae over the last cycle, and particularly around the 2003.5 low excitation event, have been obtained. The variability of both narrow and broad lines, when combined with data taken from two earlier cycles, reveal a common and well defined period. We have combined the cycle lengths derived from the many lines in the optical spectrum with those from broad-band X-rays, optical and near-infrared observations, and obtained a period length of 2022.7+-1.3 d. Spectroscopic data collected during the last 60 years yield an average period of 2020+-4 d, consistent with the present day period. The period cannot have changed by more than $\\Delta$P/P=0.0007 since 1948. This confirms the previous claims of a true, stable periodicity, and gives strong support to the binary scenario. We have used the disappearance of the narrow component of HeI 6678 to define the epoch of the Cycle 11 minimum, T_0=JD 2,452,819.8. The next event is predicted to occur on 2009 January 11 (+-2 days). The d...

  13. Eta Carinae -- Physics of the Inner Ejecta

    CERN Document Server

    Hamann, Fred

    2012-01-01

    Eta Carinae's inner ejecta are dominated observationally by the bright Weigelt blobs and their famously rich spectra of nebular emission and absorption lines. They are dense (n_e ~ 10^7 to 10^8 cm^-3), warm (T_e ~ 6000 to 7000 K) and slow moving (~40 km/s) condensations of mostly neutral (H^0) gas. Located within 1000 AU of the central star, they contain heavily CNO-processed material that was ejected from the star about a century ago. Outside the blobs, the inner ejecta include absorption-line clouds with similar conditions, plus emission-line gas that has generally lower densities and a wider range of speeds (reaching a few hundred km/s) compared to the blobs. The blobs appear to contain a negligible amount of dust and have a nearly dust-free view of the central source, but our view across the inner ejecta is severely affected by uncertain amounts of dust having a patchy distribution in the foreground. Emission lines from the inner ejecta are powered by photoionization and fluorescent processes. The variabl...

  14. Modelling the Central Constant Emission X-ray component of eta Carinae

    CERN Document Server

    Russell, Christopher M P; Hamaguchi, Kenji; Madura, Thomas I; Owocki, Stanley P; Hillier, D John

    2016-01-01

    The X-ray emission of $\\eta$ Carinae shows multiple features at various spatial and temporal scales. The central constant emission (CCE) component is centred on the binary and arises from spatial scales much smaller than the bipolar Homunculus nebula, but likely larger than the central wind--wind collision region between the stars as it does not vary over the $\\sim$2-3 month X-ray minimum when it can be observed. Using large-scale 3D smoothed particle hydrodynamics (SPH) simulations, we model both the colliding-wind region between the stars, and the region where the secondary wind collides with primary wind ejected from the previous periastron passage. The simulations extend out to one hundred semimajor axes and make two limiting assumptions (strong coupling and no coupling) about the influence of the primary radiation field on the secondary wind. We perform 3D radiative transfer calculations on the SPH output to synthesize the X-ray emission, with the aim of reproducing the CCE spectrum. For the preferred pr...

  15. Latitude-dependent effects in the stellar wind of Eta Carinae

    CERN Document Server

    Smith, N; Gull, T R; Ishibashi, K; Hillier, J; Smith, Nathan; Davidson, Kris; Gull, Theodore R.; Ishibashi, Kazunori; Hillier, John

    2003-01-01

    The Homunculus reflection nebula around eta Carinae provides a rare opportunity to observe the spectrum of a star from multiple latitudes. We present STIS spectra of several positions in the Homunculus, showing directly that eta Car has an aspherical stellar wind. P Cygni absorption in Balmer lines depends on latitude, with high velocities and strong absorption near the poles. Stronger absorption at high latitudes is surprising, and it suggests higher mass flux toward the poles, perhaps resulting from radiative driving with equatorial gravity darkening on a rotating star. Reflected profiles of He I lines are more puzzling, offering clues to the wind geometry and ionization structure. During eta Car's high-excitation state in March 2000, the wind was fast and dense at the poles, with higher ionization at low latitudes. Older STIS data obtained since 1998 reveal that this global stellar-wind geometry changes during eta Car's 5.5 year cycle, and may suggest that this star's spectroscopic events are shell ejectio...

  16. 3D modelling of the colliding winds in Eta Carinae - evidence for radiative inhibition

    CERN Document Server

    Parkin, E R; Corcoran, M F; Hamaguchi, K; Stevens, I R

    2009-01-01

    The X-ray emission from the super-massive star Eta Carinae is simulated using a three dimensional model of the wind-wind collision. In the model the intrinsic X-ray emission is spatially extended and energy dependent. Absorption due to the unshocked stellar winds and the cooled postshock material from the primary LBV star is calculated as the intrinsic emission is ray-traced along multiple sightlines through the 3D spiral structure of the circumstellar environment. The observable emission is then compared to available X-ray data, including the lightcurve observed by the Rossi X-ray Timing Explorer (RXTE) and spectra observed by XMM-Newton. The orientation and eccentricity of the orbit are explored, as are the wind parameters of the stars and the nature and physics of their close approach. Our modelling supports a viewing angle with an inclination of ~ 42 degrees, consistent with the polar axis of the Homunculus nebula (Smith 2006), and the projection of the observer's line-of-sight onto the orbital plane has ...

  17. Catalogues of planetary nebulae.

    Science.gov (United States)

    Acker, A.

    Firstly, the general requirements concerning catalogues are studied for planetary nebulae, in particular concerning the objects to be included in a catalogue of PN, their denominations, followed by reflexions about the afterlife and comuterized versions of a catalogue. Then, the basic elements constituting a catalogue of PN are analyzed, and the available data are looked at each time.

  18. Eruptive Variable Stars and Outflows in Serpens NW

    CERN Document Server

    Hodapp, Klaus W; Watermann, Ramon; Lemke, Roland

    2011-01-01

    We study the outflow activity, photometric variability and morphology of three very young stellar objects in the Serpens NW star forming region: OO Serpentis, EC 37 (V370 Ser) and EC 53 (V371 Ser). High spatial resolution Keck/NIRC2 laser guide star adaptive optics images obtained in 2007 and 2009 in broad-band K and in a narrow-band filter centered on the 1-0 S(1) emission line of molecular hydrogen allow us to identify the outflows from all three objects. We also present new, seeing-limited data on the photometric evolution of the OO Ser reflection nebula and re-analyze previously published data. We find that OO Ser declined in brightness from its outburst peak in 1995 to about 2003, but that this decline has recently stopped and actually reversed itself in some areas of the reflection nebula. The morphology and proper motions of the shock fronts MHO 2218 near EC 37 suggest that they all originate in EC 37 and that this is an outflow seen nearly along its axis. We identify a molecular hydrogen jet emerging ...

  19. Watching Young Planetary Nebulae Grow: The Movie

    Science.gov (United States)

    Balick, Bruce

    2009-07-01

    The development of magneto-hydro gas dynamical models is the key to the understanding of both the physics {processes} and astronomy {initial conditions} of astrophysical nebulae of all sorts. The models are reaching their highest degree of accuracy when applied to and compared against pre Planetary Nebulae {pPNe} thanks to the simplicity, relative lack of extinction, and the detail of the imaging and kinematic data that have bcome available for these objects. The primary barrier to progress is inadequate kinematic data of pPNe against which the predictions models can be tested. Unlike PNe, pPNe do not emit emission lines for detailed Doppler measurements. Therefore it is essential to find another way to monitor the morphological evolution. Only HST can uncover the dynamics of the growth patterns by subtracting multi-epoch images spanning a decade or more. We have selected four pPNe with highly collimated outflows in different evolutionary stages for which high-quality first-epoch images were obtained from 1996 to 2002. All of them display regularly shaped thin rims, sharp edges, and symmetric pairs of knots or bowshocks that are ideal for our purposes. We will closely mimic many of the earlier exposures using ACS and to monitor changes in structures. The morphology and its evolution will be compared to 3-D MHD models with adaptive grids in order to build a far clearer picture of the nuclear geometry which shaped the outflows and constrained their propagation to the present. We shall also obtain R, J, and H images for use with a 3-D dust radiative transfer code LELUYA to model the dust distribution deep into the nuclear zones.

  20. The San Pedro M\\'artir Kinematic Catalogue of Galactic Planetary Nebulae

    CERN Document Server

    López, J A; García-Díaz, M T; Clark, D M; Meaburn, J; Riesgo, H; Steffen, W; Lloyd, M

    2011-01-01

    The San Pedro M\\'artir kinematic catalogue of galactic planetary nebulae provides spatially resolved, long-slit Echelle spectra for about 600 planetary nebulae. The data are presented wavelength calibrated and corrected for heliocentric motion. For most objects multiple spectra have been acquired and images with accurate slit positions on the nebulae are also presented for each object. This is the most extensive and homogeneous single source of data concerning the internal kinematics of the ionized nebular material in planetary nebulae. Data can be retrieved for individual objects or selected by groups that share some common characteristics, such as by morphological classes, galactic population, binary cores, presence of fast outflows, etc. The catalogue is available through the world wide web at http://kincatpn.astrosen.unam.mx .

  1. Disks and Outflows

    Science.gov (United States)

    Rodriguez, L. F.

    2002-05-01

    The presence of disks and outflows characterizes the earliest stages of stellar evolution. I will review recent results that exemplify how the radio observations have become powerful tools in the study of these extremely young objects. Binarity and multiplicity seem to be factors that we are only starting to understand. Outflows are now seen as laboratories for the chemistry of shocked regions. Finally, the efforts to extend the paradigm for low-mass stellar formation to more massive protostars can be tested critically in the radio wavelengths. I acknowledge the support from CONACyT, Mexico.

  2. Detection of the compressed primary stellar wind in eta Carinae

    CERN Document Server

    Teodoro, M; Gull, T R; Corcoran, M F; Hamaguchi, K

    2013-01-01

    A series of three HST/STIS spectroscopic mappings, spaced approximately one year apart, reveal three partial arcs in [Fe II] and [Ni II] emissions moving outward from eta Carinae. We identify these arcs with the shell-like structures, seen in the 3D hydrodynamical simulations, formed by compression of the primary wind by the secondary wind during periastron passages.

  3. Atlantic Ocean CARINA data: overview and salinity adjustments

    Directory of Open Access Journals (Sweden)

    T. Tanhua

    2010-02-01

    Full Text Available Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruise data sets in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon dioxide IN the Atlantic Ocean. The data have gone through rigorous quality control procedures to assure the highest possible quality and consistency. The data for the pertinent parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the three data products: merged data files with measured, calculated and interpolated data for each of the three CARINA regions, i.e. the Arctic Mediterranean Seas, the Atlantic and the Southern Ocean. These products have been corrected to be internally consistent. Ninety-eight of the cruises in the CARINA database were conducted in the Atlantic Ocean, defined here as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30° S. Here we present an overview of the Atlantic Ocean synthesis of the CARINA data and the adjustments that were applied to the data product. We also report the details of the secondary QC (Quality Control for salinity for this data set. Procedures of quality control – including crossover analysis between stations and inversion analysis of all crossover data – are briefly described. Adjustments to salinity measurements were applied to the data from 10 cruises in the Atlantic Ocean region. Based on our analysis we estimate the internal consistency of the CARINA-ATL salinity data to be 4.1 ppm. With these adjustments the CARINA data products are consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example

  4. Mediterranean Outflow Mixing Dynamics

    Science.gov (United States)

    1993-02-01

    tugal. G. Parrnlla is at Instituto EspaWol Oceanografia , Fig. 2A. [Adapted from (36)] (C) The maximum observed velocity of outflow currents in the eastern...its sur- Oceanografia Fisica del Estrecho de Gibraltar, J. of Mediterranean water that we observed at the roundings (34) and retains its chemical L

  5. A wind-shell interaction model for multipolar planetary nebulae

    CERN Document Server

    Steffen, W; Esquivel, A; Garcia-Segura, G; Garcia-Diaz, Ma T; Lopez, J A; Magnor, M

    2013-01-01

    We explore the formation of multipolar structures in planetary and pre-planetary nebulae from the interaction of a fast post-AGB wind with a highly inhomogeneous and filamentary shell structure assumed to form during the final phase of the high density wind. The simulations were performed with a new hydrodynamics code integrated in the interactive framework of the astrophysical modeling package SHAPE. In contrast to conventional astrophysical hydrodynamics software, the new code does not require any programming intervention by the user for setting up or controlling the code. Visualization and analysis of the simulation data has been done in SHAPE without external software. The key conclusion from the simulations is that secondary lobes in planetary nebulae, such as Hubble 5 and K3-17, can be formed through the interaction of a fast low-density wind with a complex high density environment, such as a filamentary circumstellar shell. The more complicated alternative explanation of intermittent collimated outflow...

  6. Prediction of close binarity based on planetary nebula morphology

    CERN Document Server

    Miszalski, B; Jones, D; Santander-García, M; Rodríguez-Gil, P; Rubio-Díez, M M

    2010-01-01

    A thorough search of the OGLE-III microlensing project has more than doubled the total sample of PNe known to have close binary central stars. These discoveries have enabled close binary induced morphological trends to be revealed for the first time. Canonical bipolar nebulae, low-ionisation structures and polar outflows are all identified within the sample and are provisionally associated with binarity. We have embarked upon a large photometric monitoring program using the Flemish Mercator telescope to simultaneously test the predictive power of these morphological features and to find more close binaries. Early results are very positive with at least five binaries found so far. This suggests our method is an effective means to expedite the construction of a statistically significant sample of close binary shaped nebulae. Such an authoritative sample will be essential to quantify the degree to which close binary nuclei may shape PNe.

  7. Million-degree plasma pervading the extended Orion Nebula.

    Science.gov (United States)

    Güdel, Manuel; Briggs, Kevin R; Montmerle, Thierry; Audard, Marc; Rebull, Luisa; Skinner, Stephen L

    2008-01-18

    Most stars form as members of large associations within dense, very cold (10 to 100 kelvin) molecular clouds. The nearby giant molecular cloud in Orion hosts several thousand stars of ages less than a few million years, many of which are located in or around the famous Orion Nebula, a prominent gas structure illuminated and ionized by a small group of massive stars (the Trapezium). We present x-ray observations obtained with the X-ray Multi-Mirror satellite XMM-Newton, revealing that a hot plasma with a temperature of 1.7 to 2.1 million kelvin pervades the southwest extension of the nebula. The plasma flows into the adjacent interstellar medium. This x-ray outflow phenomenon must be widespread throughout our Galaxy.

  8. GALAXY OUTFLOWS WITHOUT SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Sur, Sharanya [Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore 560034 (India); Scannapieco, Evan [School of Earth and Space Exploration, Arizona State University, P.O. Box 876004, Tempe-85287 (United States); Ostriker, Eve C., E-mail: sharanya.sur@iiap.res.in, E-mail: sharanya.sur@asu.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2016-02-10

    High surface density, rapidly star-forming galaxies are observed to have ≈50–100 km s{sup −1} line of sight velocity dispersions, which are much higher than expected from supernova driving alone, but may arise from large-scale gravitational instabilities. Using three-dimensional simulations of local regions of the interstellar medium, we explore the impact of high velocity dispersions that arise from these disk instabilities. Parametrizing disks by their surface densities and epicyclic frequencies, we conduct a series of simulations that probe a broad range of conditions. Turbulence is driven purely horizontally and on large scales, neglecting any energy input from supernovae. We find that such motions lead to strong global outflows in the highly compact disks that were common at high redshifts, but weak or negligible mass loss in the more diffuse disks that are prevalent today. Substantial outflows are generated if the one-dimensional horizontal velocity dispersion exceeds ≈35 km s{sup −1}, as occurs in the dense disks that have star-formation rate (SFR) densities above ≈0.1 M{sub ⊙} yr{sup −1} kpc{sup −2}. These outflows are triggered by a thermal runaway, arising from the inefficient cooling of hot material coupled with successive heating from turbulent driving. Thus, even in the absence of stellar feedback, a critical value of the SFR density for outflow generation can arise due to a turbulent heating instability. This suggests that in strongly self-gravitating disks, outflows may be enhanced by, but need not caused by, energy input from supernovae.

  9. The CARINA data synthesis project: introduction and overview

    Energy Technology Data Exchange (ETDEWEB)

    Key, Robert [Princeton University; Tanhua, T. [IFM-GEOMAR, Leibniz Institute for Marine Sciences, Chemical Oceanography, Kiel, Germany; Olsen, Are [Bjerknes Centre for Climate Research, UNIFOB AS, Bergen, Norway; Hoppema, M. [Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany; Jutterström, S. [University of Gothenburg, Sweden; Schirnick, C. [IFM-GEOMAR, Leibniz Institute for Marine Sciences, Chemical Oceanography, Kiel, Germany; Van Heuven, S. [University of Groningen, The Netherlands; Kozyr, Alexander [ORNL; Lin, X. [Princeton University; Velo, A. [Instituto de Investigaciones Marinas de Vigo, CSIC, Vigo, Spain; Wallace, D.W.R. [IFM-GEOMAR, Leibniz Institute for Marine Sciences, Chemical Oceanography, Kiel, Germany; Mintrop, L. [MARIANDA marine analytics and data, Kiel, Germany

    2010-01-01

    The original goal of the CARINA (Carbon in Atlantic Ocean) data synthesis project was to create a merged calibrated data set from open ocean subsurface measurements by European scientists that would be generally useful for biogeochemical investigations in the North Atlantic and in particular, studies involving the carbon system. Over time the geographic extent expanded to include the entire Atlantic, the Arctic and the Southern Ocean and the international collaboration broadened significantly. In this paper we give a brief history of the project, a general overview of data included and an outline of the procedures used during the synthesis. The end result of this project was a set of 3 data products, one for each of the listed ocean regions. It is critical that anyone who uses any of the CARINA data products recognize that the data products are not simply concatenations of the originally measured values. Rather, the data have been through an extensive calibration procedure designed to remove measurement bias and bad data. Also a significant fraction of the individual values in the data products were derived either by direct calculation or some means of approximation. These data products were constructed for basin scale biogeochemical investigations and may be inappropriate for investigations involving small areal extent or similar detailed analysis. More information on specific parts of this project can be found in companion articles in this issue. In particular, Tanhua et al. (2010) and Tanhua (2009) describe the procedures and software used to remove measurement bias from the original data. The three data products and a significant volume of supporting information are available from the CARINA web site hosted by the Carbon Dioxide Information Analysis Center (CDIAC: http://cdiac.esd.ornl.gov/oceans/CARINA/Carina inv.html). Anyone wanting to use the data is advised to get the highest version number of each data product. Incremental versions represent either

  10. Ejecta of Eta Carinae: What We Learn about N-Rich Chemistry

    Science.gov (United States)

    Gull, Theodore

    2006-01-01

    At least one member of the binary system, Eta Carinae, is in the late stages of CNO-cycle. At least ten solar masses of ejecta make up the Homunculus, a neutral bi-polar shell ejected in the 1840s and the Little Homunculus, an internal, ionized bi-polar shell ejected in the 1890s. HST/STIS and VLTAJVES high dispersion spectroscopy revealed absorptions of multiple elements and diatomic molecules in these shells, some, such as V II and Sr II have not been seen previously in the ISM. The skirt region between the bi-lobes includes the very bright Weigelt blobs, within 0.1 to 0.3" of the central source, and the more distant, unusual Strontium Filament, a neutral emission nebula photoexcited by Balmer continuum, but shielded by Fe II from Lyman radiation. The 600+ emission lines are due to metals usually tied up in dust, but underabundances of C and O prevent precipitation as oxides onto the dust grains. Indications are that Ti/Ni is 100X solar, likely due not to nuclear processing, but the very different photo-excitation environments coupled with N-rich, C-, O-poor chemistry. In the Homunculus, level populations of the molecules indicate 60K gas; the metal absorption lines, 760K; that of the Little Homunculus 6400K during the broad spectroscopic maximum, relaxing to 5000K for the few month long minimum. Lyman radiation, including both continuum and Lyman lines, is trapped across periastron. leading to temporary relaxation of the ejecta. These ejecta are a treasure trove of information on material thrown out of massive stars in the CNO-cycle, well before the helium burning phase. Curiously, spectra of three very recent SWIFT GRBs indicate the presence of warm, photoexcited ejecta in the vicinity of the protoGRBs, but obviously of very different abundances. However, the ejecta of Eta Carinae promise to be a nearby example of massive ejecta, the study of which should lead to increased insight of earlier, very distant massive stars.

  11. The deep OB star population in Carina from the VST Photometric Hα Survey (VPHAS+)

    Science.gov (United States)

    Mohr-Smith, M.; Drew, J. E.; Napiwotzki, R.; Simón-Díaz, S.; Wright, N. J.; Barentsen, G.; Eislöffel, J.; Farnhill, H. J.; Greimel, R.; Monguió, M.; Kalari, V.; Parker, Q. A.; Vink, J. S.

    2017-02-01

    Massive OB stars are critical to the ecology of galaxies and yet our knowledge of OB stars in the Milky Way, fainter than V ˜ 12, remains patchy. Data from the VST Photometric Hα Survey (VPHAS+) permit the construction of the first deep catalogues of blue excess-selected OB stars, without neglecting the stellar field. A total of 14 900 candidates with 2MASS cross-matches are blue-selected from a 42 deg2 region in the Galactic plane, capturing the Carina Arm over the Galactic longitude range 282° ≲ ℓ ≲ 293°. Spectral energy distribution fitting is performed on these candidates' combined VPHAS+ u, g, r, i and 2MASS J, H, K magnitudes. This delivers effective temperature constraints, statistically separating O from early-B stars and high-quality extinction parameters, A0 and RV (random errors typically ˜0.1). The high-confidence O-B2 candidates number 5915 and a further 5170 fit to later B spectral type. Spectroscopy of 276 of the former confirms 97 per cent of them. The fraction of emission-line stars among all candidate B stars is 7-8 per cent. Greyer (RV > 3.5) extinction laws are ubiquitous in the region, over the distance range 2.5-3 to ˜10 kpc. Near prominent massive clusters, RV tends to rise, with particularly large and chaotic excursions to RV ˜ 5 seen in the Carina Nebula. The data reveal a hitherto unnoticed association of 108 O-B2 stars around the O5If+ star LSS 2063 (ℓ = 289.77°, b = -1.22°). Treating the OB star scaleheight as a constant within the thin disc, we find an orderly mean relation between extinction (A0) and distance in the Galactic longitude range, 287.6° < ℓ < 293.5°, and infer the subtle onset of thin-disc warping. A halo around NGC 3603, roughly a degree in diameter, of ˜500 O-B2 stars with 4 < A0(mag) < 7 is noted.

  12. H2 in low-ionization structures of planetary nebulae

    Science.gov (United States)

    Akras, Stavros; Gonçalves, Denise R.; Ramos-Larios, Gerardo

    2017-02-01

    We report the detection of near-IR H2 emission from the low-ionization structures (knots) in two planetary nebulae. The deepest ever high-angular-resolution H2 (1-0) S(1) at 2.122 μm, H2 (2-1) S(1) at 2.248 μm and Brγ images of K 4-47 and NGC 7662, obtained using the Near InfraRed Imager and Spectrometer (NIRI) at Gemini-North, are analysed here. K 4-47 reveals a remarkable highly collimated bipolar structure not only in the optical but also in the molecular hydrogen emission. The H2 emission emanates from the walls of the bipolar outflows and also from the pair of knots at the tip of the outflows. The H2 (1-0) S(1)/(2-1) S(1) line ratio ranges from ˜7 to ˜10, suggesting the presence of shock interactions. Our findings can be explained by the interaction of a jet/bullet ejected from the central star with the surrounding asymptotic giant branch material. The strongest H2 line, (1-0) S(1), is also detected in several low-ionization knots located at the periphery of the elliptical planetary nebula NGC 7662, but only four of these knots are detected in the H2 (2-1) S(1) line. These four knots exhibit an H2 line ratio between 2 and 3.5, which suggests that the emission is caused by the UV ionizing flux of the central star. Our data confirm the presence of H2 gas in both fast- and slow-moving low-ionization knots, which has only been confirmed before in the nearby Helix nebula and Hu 1-2. Overall, the low-ionization structures of planetary nebulae are found to have similar traits to photodissociation regions.

  13. ALMA Observations of the Coldest Place in the Universe: The Boomerang Nebula

    CERN Document Server

    Sahai, R; Huggins, P J; Nyman, L-A; Gonidakis, I

    2013-01-01

    The Boomerang Nebula is the coldest known object in the Universe, and an extreme member of the class of Pre-Planetary Nebulae, objects which represent a short-lived transitional phase between the AGB and Planetary Nebula evolutionary stages. Previous single-dish CO (J=1-0) observations (with a 45 arcsec beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang with ALMA in the CO J=2-1 and J=1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with HST and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter ...

  14. Gemini GMOS and WHT SAURON integral-field spectrograph observations of the AGN-driven outflow in NGC 1266

    NARCIS (Netherlands)

    Davis, Timothy A.; Krajnović, Davor; McDermid, Richard M.; Bureau, Martin; Sarzi, Marc; Nyland, Kristina; Alatalo, Katherine; Bayet, Estelle; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Cappellari, Michele; Crocker, Alison; Davies, Roger L.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2012-01-01

    We use the Spectrographic Areal Unit for Research on Optical Nebulae and Gemini Multi-Object Spectrograph integral-field spectrographs to observe the active galactic nucleus (AGN) powered outflow in NGC 1266. This unusualgalaxy is relatively nearby (D = 30 Mpc), allowing us to investigate the proces

  15. Gemini GMOS and WHT SAURON integral-field spectrograph observations of the AGN-driven outflow in NGC 1266

    NARCIS (Netherlands)

    Davis, Timothy A.; Krajnovic, Davor; McDermid, Richard M.; Bureau, Martin; Sarzi, Marc; Nyland, Kristina; Alatalo, Katherine; Bayet, Estelle; Blitz, Leo; Bois, Maxime; Bournaud, Frederic; Cappellari, Michele; Crocker, Alison; Davies, Roger L.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2012-01-01

    We use the Spectrographic Areal Unit for Research on Optical Nebulae and Gemini Multi-Object Spectrograph integral-field spectrographs to observe the active galactic nucleus (AGN) powered outflow in NGC?1266. This unusual galaxy is relatively nearby (D = 30?Mpc), allowing us to investigate the proce

  16. Learning about the magnetar Swift J1834.9-0846 from its wind nebula

    Science.gov (United States)

    Granot, Jonathan; Gill, Ramandeep; Younes, George; Gelfand, Josef; Harding, Alice; Kouveliotou, Chryssa; Baring, Matthew G.

    2017-02-01

    The first wind nebula around a magnetar was recently discovered in X-rays around Swift J1834.9-0846. We study this magnetar's global energetics and the properties of its particle wind or outflows. At a distance of ˜4 kpc, Swift J1834.9-0846 is located at the centre of the supernova remnant (SNR) W41 whose radius is ˜19 pc, an order of magnitude larger than that of the X-ray nebula (˜2 pc). The association with SNR W41 suggests a common age of ˜5-100 kyr, while its spin-down age is 4.9 kyr. A small natal kick velocity may partly explain why a wind nebula was detected around this magnetar but not around other magnetars, most of which appear to have larger kick velocities and may have exited their birth SNR. We find that the GeV and TeV source detected by Fermi/Large Area Telescope (LAT) and High Energy Spectroscopic System (H.E.S.S.), respectively, of radius ˜11 pc is most likely of hadronic origin. The dynamics and internal structure of the nebula are examined analytically to explain the nebula's current properties. Its size may naturally correspond to the diffusion-dominated cooling length of the X-ray emitting e+e- pairs. This may also account for the spectral softening of the X-ray emission from the nebula's inner to outer parts. The analysis of the X-ray synchrotron nebula implies that (i) the nebular magnetic field is ≳ 11 μG (and likely ≲ 30 μG), and (ii) the nebula is not powered predominantly by the magnetar's quiescent spin-down-powered MHD wind, but by other outflows that contribute most of its energy. The latter are most likely associated with the magnetar's bursting activity, and possibly dominated by outflows associated with its past giant flares. The energy source for the required outflows cannot be the decay of the magnetar's dipole field alone, and is most likely the decay of its much stronger internal magnetic field.

  17. Physical Structure of Planetary Nebulae. I. The Owl Nebula

    CERN Document Server

    Guerrero, M A; Manchado, A; Kwitter, K B

    2003-01-01

    The Owl Nebula is a triple-shell planetary nebula with the outermost shell being a faint bow-shaped halo. We have obtained deep narrow-band images and high-dispersion echelle spectra in the H-alpha, [O III], and [N II] emission lines to determine the physical structure of each shell in the nebula. These spatio-kinematic data allow us to rule out hydrodynamic models that can reproduce only the nebular morphology. Our analysis shows that the inner shell of the main nebula is slightly elongated with a bipolar cavity along its major axis, the outer nebula is a filled envelope co-expanding with the inner shell at 40 km/s, and the halo has been braked by the interstellar medium as the Owl Nebula moves through it. To explain the morphology and kinematics of the Owl Nebula, we suggest the following scenario for its formation and evolution. The early mass loss at the TP-AGB phase forms the halo, and the superwind at the end of the AGB phase forms the main nebula. The subsequent fast stellar wind compressed the superwi...

  18. Galaxy Outflows Without Supernovae

    CERN Document Server

    Sur, Sharanya; Ostriker, Eve C

    2016-01-01

    High surface density, rapidly star-forming galaxies are observed to have $\\approx 50-100\\,{\\rm km\\,s^{-1}}$ line-of-sight velocity dispersions, which are much higher than expected from supernova driving alone, but may arise from large-scale gravitational instabilities. Using three-dimensional simulations of local regions of the interstellar medium, we explore the impact of high velocity dispersions that arise from these disk instabilities. Parametrizing disks by their surface densities and epicyclic frequencies, we conduct a series of simulations that probe a broad range of conditions. Turbulence is driven purely horizontally and on large scales, neglecting any energy input from supernovae. We find that such motions lead to strong global outflows in the highly-compact disks that were common at high redshifts, but weak or negligible mass loss in the more diffuse disks that are prevalent today. Substantial outflows are generated if the one-dimensional horizontal velocity dispersion exceeds $\\approx 35\\,{\\rm km\\...

  19. Magnetic Fields in Paradigms of Planetary Nebulae and Related MHD Frontiers

    CERN Document Server

    Blackman, Eric G

    2008-01-01

    Many, if not all, post AGB stellar systems swiftly transition from a spherical to a powerful aspherical pre-planetary nebula (pPNE) outflow phase before waning into a PNe. The pPNe outflows require engine rotational energy and a mechanism to extract this energy into collimated outflows. Just radiation and rotation are insufficient but a symbiosis between rotation, differential rotation and large scale magnetic fields remains promising. Present observational evidence for magnetic fields in evolved stars is suggestive of dynamically important magnetic fields, but both theory and observation are rife with research opportunity. I discuss how magnetohydrodynamic outflows might arise in pPNe and PNe and distinguish different between approaches that address shaping vs. those that address both launch and shaping. Scenarios involving dynamos in single stars, binary driven dynamos, or accretion engines cannot be ruled out. One appealing paradigm involves accretion onto the primary post-AGB white dwarf core from a low m...

  20. Super-Acceleration in the Flaring Crab Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Tavani, Marco, E-mail: marco.tavani@inaf.it

    2013-10-15

    The Crab Nebula continues to surprise us. The Crab system (energized by a very powerful pulsar at the center of the Supernova Remnant SN1054) is known to be a very efficient particle “accelerator” which can reach PeV energies. Today, new surprising data concerning the gamma-ray flares produced by the Crab Nebula challenge models of particle acceleration. The total energy flux from the Crab has been considered for many decades substantially stable at X-ray and gamma-ray energies. However, this paradigm was shattered by the AGILE discovery and Fermi confirmation in September 2010 of transient gamma-ray emission from the Crab. Indeed, we can state that four major flaring gamma-ray episodes have been detected by AGILE and Fermi during the period mid-2007/2012. During these events, transient particle acceleration occurs in a regime which apparently violates the MHD conditions and synchrotron cooling constraints. This fact justifies calling “super-acceleration” the mechanism which produces the “flaring Crab phenomenon”. Radiation between 50 MeV and a few GeV is emitted with a quite hard spectrum within a short timescale (hours-days), with no obvious relation with simultaneous optical and X-ray emissions in the inner Nebula. “Super-acceleration” implies overcoming synchrotron cooling by strong (and “parallel”) electric fields most likely produced by magnetic field reconnection within the pulsar wind outflow. This acceleration appears to be very efficient and, remarkably, limited by radiation reaction. It is not clear at the moment where in the Nebula this phenomenon occurs. An intense observational program is now focused on the Crab Nebula to resolve its most challenging mystery.

  1. Ghost Head Nebula

    Science.gov (United States)

    1999-01-01

    Looking like a colorful holiday card, a new image from NASA's Hubble Space Telescope reveals a vibrant green and red nebula far from Earth. The image of NGC 2080, taken by Hubble's Wide Field and Planetary Camera 2, designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif., is available online at http://www.jpl.nasa.gov/images/wfpc . Images like this help astronomers investigate star formation in nebulas. NGC 2080, nicknamed 'The Ghost Head Nebula,' is one of a chain of star-forming regions lying south of the 30 Doradus nebula in the Large Magellanic Cloud. 30 Doradus is the largest star-forming complex in the local group of galaxies. This 'enhanced color' picture is composed of three narrow-band-filter images obtained by Hubble on March 28, 2000. The red and blue light come from regions of hydrogen gas heated by nearby stars. The green light on the left comes from glowing oxygen. The energy to illuminate the green light is supplied by a powerful stellar wind, a stream of high-speed particles coming from a massive star just outside the image. The central white region is a combination of all three emissions and indicates a core of hot, massive stars in this star-formation region. Intense emission from these stars has carved a bowl-shaped cavity in surrounding gas. In the white region, the two bright areas (the 'eyes of the ghost') - named A1 (left) and A2 (right) -- are very hot, glowing 'blobs' of hydrogen and oxygen. The bubble in A1 is produced by the hot, intense radiation and powerful stellar wind from one massive star. A2 contains more dust and several hidden, massive stars. The massive stars in A1 and A2 must have formed within the last 10,000 years, since their natal gas shrouds are not yet disrupted by the powerful radiation of the newborn stars. The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The

  2. Rotten Egg Nebula

    Science.gov (United States)

    1999-01-01

    Violent gas collisions that produced supersonic shock fronts in a dying star are seen in a new, detailed image from NASA's Hubble Space Telescope. The picture, taken by Hubble's Wide Field and Planetary Camera 2, is online at http://www.jpl.nasa.gov/images/wfpc . The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Stars like our Sun will eventually die and expel most of their material outward into shells of gas and dust. These shells eventually form some of the most beautiful objects in the universe, called planetary nebulae. 'This new image gives us a rare view of the early death throes of stars like our Sun. For the first time, we can see phenomena leading to the formation of planetary nebulae. Until now, this had only been predicted by theory, but had never been seen directly,' said Dr. Raghvendra Sahai, research scientist and member of the science team at JPL for the Wide Field and Planetary Camera 2. The object is sometimes called the Rotten Egg Nebula, because it contains a lot of sulphur, which would produce an awful odor if one could smell in space. The object is also known as the Calabash Nebula or by the technical name OH231.8+4.2. The densest parts of the nebula are composed of material ejected recently by the central star and accelerated in opposite directions. This material, shown as yellow in the image, is zooming away at speeds up to one and a half million kilometers per hour (one million miles per hour). Most of the star's original mass is now contained in these bipolar gas structures. A team of Spanish and American astronomers used NASA's Hubble Space Telescope to study how the gas stream rams into the surrounding material, shown in blue. They believe that such interactions dominate the formation process in planetary nebulae. Due to the high speed of the gas, shock-fronts are formed on impact and heat the surrounding gas. Although computer calculations have predicted the existence and structure of such shocks for

  3. Volumetric Image Guidance Using Carina vs Spine as Registration Landmarks for Conventionally Fractionated Lung Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lavoie, Caroline; Higgins, Jane; Bissonnette, Jean-Pierre [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, M5G 2M9 (Canada); Le, Lisa W. [Department of Biostatistics, Princess Margaret Hospital, Toronto, Ontario, M5G 2M9 (Canada); Sun, Alexander; Brade, Anthony; Hope, Andrew; Cho, John [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, M5G 2M9 (Canada); Bezjak, Andrea, E-mail: andrea.bezjak@rmp.uhn.on.ca [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, M5G 2M9 (Canada)

    2012-12-01

    Purpose: To compare the relative accuracy of 2 image guided radiation therapy methods using carina vs spine as landmarks and then to identify which landmark is superior relative to tumor coverage. Methods and Materials: For 98 lung patients, 2596 daily image-guidance cone-beam computed tomography scans were analyzed. Tattoos were used for initial patient alignment; then, spine and carina registrations were performed independently. A separate analysis assessed the adequacy of gross tumor volume, internal target volume, and planning target volume coverage on cone-beam computed tomography using the initial, middle, and final fractions of radiation therapy. Coverage was recorded for primary tumor (T), nodes (N), and combined target (T+N). Three scenarios were compared: tattoos alignment, spine registration, and carina registration. Results: Spine and carina registrations identified setup errors {>=}5 mm in 35% and 46% of fractions, respectively. The mean vector difference between spine and carina matching had a magnitude of 3.3 mm. Spine and carina improved combined target coverage, compared with tattoos, in 50% and 34% (spine) to 54% and 46% (carina) of the first and final fractions, respectively. Carina matching showed greater combined target coverage in 17% and 23% of fractions for the first and final fractions, respectively; with spine matching, this was only observed in 4% (first) and 6% (final) of fractions. Carina matching provided superior nodes coverage at the end of radiation compared with spine matching (P=.0006), without compromising primary tumor coverage. Conclusion: Frequent patient setup errors occur in locally advanced lung cancer patients. Spine and carina registrations improved combined target coverage throughout the treatment course, but carina matching provided superior combined target coverage.

  4. Overview of the Nordic Seas CARINA data and salinity measurements

    Directory of Open Access Journals (Sweden)

    R. M. Key

    2009-07-01

    Full Text Available Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruises in the Arctic, Atlantic, and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon IN the Atlantic. The data have been subject to rigorous quality control (QC in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the data products, i.e. the three merged files with measured, calculated and interpolated values for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS, the Atlantic (ATL and the Southern Ocean (SO. With the adjustments the CARINA database is consistent both internally as well as with GLODAP (Key et al., 2004 and is suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation. The Arctic Mediterranean Seas includes the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas. This contribution provides an overview of the CARINA data from the Nordic Seas and summarises the findings of the QC of the salinity data. One cruise had salinity data that were of questionable quality, and these have been removed from the data product. An evaluation of the consistency of the quality controlled salinity data suggests that they are consistent to at least 0.05.

  5. Overview of the Nordic Seas CARINA data and salinity measurements

    Directory of Open Access Journals (Sweden)

    A. Olsen

    2009-11-01

    Full Text Available Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruises in the Arctic, Atlantic, and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon IN the Atlantic. The data have been subject to rigorous quality control (QC in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the data products, i.e. the three merged files with measured, calculated and interpolated values for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS, the Atlantic (ATL and the Southern Ocean (SO. With the adjustments the CARINA database is consistent both internally as well as with GLODAP (Key et al., 2004 and is suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation. The Arctic Mediterranean Seas include the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas. This contribution provides an overview of the CARINA data from the Nordic Seas and summarises the findings of the QC of the salinity data. One cruise had salinity data that were of questionable quality, and these have been removed from the data product. An evaluation of the consistency of the quality controlled salinity data suggests that they are consistent to at least ±0.005.

  6. The 1981 mass-loss phase of Eta Carinae

    Science.gov (United States)

    Bidelman, William P.; Galen, Tamara A.; Wallerstein, George

    1993-07-01

    A visual-region coude spectrogram of Eta Carinae taken in 1981 May is described, and the portion of the spectrum containing H-alpha is reproduced. This was taken during one of Eta Car's 'abnormal' stages, which have been suggested by Zanella et al. (1984) to be times of large mass loss from this unique object. The 1981 spectrum is compared with the 'normal' spectrum as observed in 1985.

  7. The Carina Project IX: on Hydrogen and helium burning variables

    CERN Document Server

    Coppola, G; Stetson, P B; Bono, G; Braga, V F; Ripepi, V; Dall'Ora, M; Musella, I; Buonanno, R; Fabrizio, M; Ferraro, I; Fiorentino, G; Iannicola, G; Monelli, M; Nonino, M; Thévenin, F; Walker, R

    2015-01-01

    We present new multi-band (UBVI) time-series data of helium burning variables in the Carina dwarf spheroidal galaxy. The current sample includes 92 RR Lyrae-six of them are new identifications-and 20 Anomalous Cepheids, one of which is new identification. The analysis of the Bailey diagram shows that the luminosity amplitude of the first overtone component in double-mode variables is located along the long-period tail of regular first overtone variables, while the fundamental component is located along the short-period tale of regular fundamental variables. This evidence further supports the transitional nature of these objects. Moreover, the distribution of Carina double-mode variables in the Petersen diagram (P_1/P_0 vs P_0) is similar to metal-poor globulars (M15, M68), to the dwarf spheroidal Draco and to the Galactic Halo. This suggests that the Carina old stellar population is metal-poor and affected by a small spread in metallicity. We use trigonometric parallaxes for five field RR Lyrae stars to provi...

  8. Searching for Brown Dwarf Outflows

    CERN Document Server

    Whelan, E T; Bacciotti, F; Randich, S; Natta, A

    2009-01-01

    As outflow activity in low mass protostars is strongly connected to ac- cretion it is reasonable to expect accreting brown dwarfs to also be driving out- flows. In the last three years we have searched for brown dwarf outflows using high quality optical spectra obtained with UVES on the VLT and the technique of spectro-astrometry. To date five brown dwarf outflows have been discovered. Here the method is discussed and the results to date outlined.

  9. Flames High Resolution Spectroscopy of RGB Stars in the Carina Dwarf Spheroidal Galaxy

    NARCIS (Netherlands)

    Lemasle, B.; Hill, V.; Tolstoy, E.; Venn, K.

    2011-01-01

    Carina is a small and faint classical dwarf spheroidal galaxy in the halo of the Milky Way with a highly episodic star formation history (e.g., Hurley-Keller et al. 1998). Using VLT/FLAMES in high resolution mode, we significantly increase the sample of stars with abundance determinations in Carina,

  10. THE SHAPING OF THE MULTIPOLAR PRE-PLANETARY NEBULA CRL 618 BY MULTIDIRECTIONAL BULLETS

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Po-Sheng; Lee, Chin-Fei; Moraghan, Anthony [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China); Smith, Michael, E-mail: posheng@asiaa.sinica.edu.tw [Centre for Astrophysics and Space Science, University of Kent, Canterbury CT2 7NH (United Kingdom)

    2016-04-01

    In order to understand the formation of the multipolar structures of the pre-planetary nebula CRL 618, we perform 3D simulations using a multidirectional bullet model. The optical lobes of CRL 618 and fast molecular outflows at the tips of the lobes have been found to have similar expansion ages of ∼100 yr. Additional fast molecular outflows were found near the source along the outflow axes with ages of ∼45 yr, suggesting a second episode of bullet ejections. Thus, in our simulations, two episodes of bullet ejections are assumed. The shaping process is simulated using the ZEUS-3D hydrodynamics code that includes molecular and atomic cooling. In addition, molecular chemistry is also included to calculate the CO intensity maps. Our results show the following: (1) Multiepoch bullets interacting with the toroidal dense core can produce the collimated multiple lobes as seen in CRL 618. The total mass of the bullets is ∼0.034 M{sub ⊙}, consistent with the observed high-velocity (HV) CO emission in fast molecular outflows. (2) The simulated CO J = 3–2 intensity maps show that the low-velocity cavity wall and the HV outflows along the lobes are reasonably consistent with the observations. The position–velocity diagram of the outflows along the outflow axes shows a linear increase of velocity with distance, similar to the observations. The ejections of these bullets could be due to magnetorotational explosions or nova-like explosions around a binary companion.

  11. Unveiling the structure of the planetary nebula M 2-48 Kinematics and physical conditions

    CERN Document Server

    López-Martin, L; Esteban, C; Vázquez, R; Raga, A C; Torrelles, J M; Miranda, L F; Meaburn, J; Olguin, L

    2002-01-01

    The kinematics and physical conditions of the bipolar planetary nebula M 2-48 are analysed from high and low dispersion long-slit spectra. Previous CCD narrow-band optical observations have suggested that this nebula is mainly formed by a pair of symmetric bow-shocks, an off-center semi-circular shell, and an internal bipolar structure. The bipolar outflow has a complex structure, characterised by a series of shocked regions located between the bright core and the polar tips. There is an apparent kinematic discontinuity between the bright bipolar core and the outer regions. The fragmented ring around the bright bipolar region presents a low expansion velocity and could be associated to ejection in the AGB-PN transition phase, although its nature remains unclear. The chemical abundances of the central region are derived, showing that M 2-48 is a Type I planetary nebula (PN).

  12. Distances from Planetary Nebulae

    CERN Document Server

    Ciardullo, R

    2003-01-01

    The [O III] 5007 planetary nebula luminosity function (PNLF) occupies an important place on the extragalactic distance ladder. Since it is the only method that is applicable to all the large galaxies of the Local Supercluster, it is uniquely useful for cross-checking results and linking the Population I and Population II distance scales. We review the physics underlying the method, demonstrate its precision, and illustrate its value by comparing its distances to distances obtained from Cepheids and the Surface Brightness Fluctuation (SBF) method. We use the Cepheid and PNLF distances to 13 galaxies to show that the metallicity dependence of the PNLF cutoff is in excellent agreement with that predicted from theory, and that no additional systematic corrections are needed for either method. However, when we compare the Cepheid-calibrated PNLF distance scale with the Cepheid-calibrated SBF distance scale, we find a significant offset: although the relative distances of both methods are in excellent agreement, th...

  13. Molecular studies of Planetary Nebulae

    OpenAIRE

    Zhang, Yong

    2016-01-01

    Circumstellar envelopes (CEs) around evolved stars are an active site for the production of molecules. After evolving through the Asymptotic Giant Branch (AGB), proto-planetary nebula (PPN), to planetary nebula (PN) phases, CEs ultimately merge with the interstellar medium (ISM). The study of molecules in PNe, therefore, is essential to understanding the transition from stellar to interstellar materials. So far, over 20 molecular species have been discovered in PNe. The molecular composition ...

  14. Absorbing Outflows in AGN

    Science.gov (United States)

    Mathur, Smita

    2002-01-01

    The goal of this program was a comprehensive multiwavelength study of absorption phenomena in active galactic nuclei (AGN). These include a variety of associated absorption systems: X-ray warm absorbers, X-ray cold absorbers. UV absorbers with high ionization lines, MgII absorbers, red quasars and BALQSOs. The aim is to determine the physical conditions in the absorbing outflows, study their inter-relations and their role in AGN. We designed several observing programs to achieve this goal: X-ray spectroscopy, UV spectroscopy, FLAY spectroscopy and X-ray imaging. We were very successful towards achieving the goal over the five year period as shown through following observing programs and papers. Copies of a few papers are attached with this report.

  15. Observations of Molecular Outflow in Car 291.6-01.9

    Science.gov (United States)

    Saul, M.; Saul, L.

    2012-01-01

    We report the first observations of a dense molecular gas nebula and bipolar outflow in Car 291.6-01.9, showing characteristics of an embedded young stellar object (YSO). Using the Mopra radio telescope near Coonabarabaran, Australia, we image the kinematic structure of several emission features to examine physical properties within a molecular clump of mass ~3.2 ± 0.6 × 103 M ⊙ in which a stellar cluster may be forming. Motivated by acquiring a more thorough understanding of star formation we ask what may have initiated collapse in the clump; observed outflow alignment is suggestive of ~1.0 pc distant massive star HD 308280 radiative-driven compression as a formation trigger for the dense core. An outflow derived age of <106 years, together with significant C18O and SO core depletion, support the case for the core as the host of an extremely YSO cluster.

  16. A Highly Collimated, Young and Fast CO(2-1) Outflow in OMC1 South

    CERN Document Server

    Zapata, L A; Ho, P T P; Zhang, Q; Qi, C; Kurtz, S E; Zapata, Luis A.; Rodriguez, Luis F.; Ho, Paul T.P.; Zhang, Qizhou; Qi, Chunhua

    2005-01-01

    We present high angular resolution (~ 1''), sensitive CO(2-1) line observations of the region OMC1 South in the Orion Nebula made using the Submillimeter Array (SMA). We detect the CO(2-1) high velocity outflow that was first found by Rodriguez-Franco et al. (1999a) with the IRAM 30 m. Our observations resolve the outflow, whose velocity-integrated emission has a deconvolved width of 0.89'' \\pm 0.06'' (490 AU) and a projected length of ~ 48'' (21,000 AU) with very high redshifted and blueshifted gas with velocities of about \\pm 80 km/s. This outflow is among the most collimated (~ 3 degrees) and youngest outflows (600 yr) that have been reported. The data show that this collimated outflow has been blowing in the same direction during the last 600 yr. At high velocities, the CO(2-1) outflow traces an extremely collimated jet, while at lower velocities the CO emission traces an envelope possibly produced by entrainment of ambient gas. Furthermore, we also detect for the first time a millimeter wavelength contin...

  17. Modelling the Radio Light Curve of Eta Carinae

    OpenAIRE

    Kashi, Amit; Soker, Noam

    2007-01-01

    We study the propagation of the ionizing radiation emitted by the secondary star in Eta Carinae. We find that a large fraction of this radiation is absorbed by the primary stellar wind, mainly after it encounters the secondary wind and passes through a shock wave. The amount of absorption depends on the compression factor of the primary wind in the shock wave. We build a model where the compression factor is limited by the magnetic pressure in the primary wind. We find that the variation of t...

  18. Learning About the Magnetar Swift J1834.9-0846 from its Wind Nebula

    CERN Document Server

    Granot, Jonathan; Younes, George; Gelfand, Josef; Harding, Alice; Kouveliotou, Chryssa; Baring, Matthew G

    2016-01-01

    The first wind nebula around a magnetar was recently discovered in X-rays around Swift~J1834.9$-$0846. We study this magnetar's global energetics and the properties of its particle wind or outflows. At a distance of $\\sim4\\;$kpc, Swift~J1834.9$-$0846 is located at the center of the supernova remnant (SNR) W41 whose radius is $\\sim 19\\;$pc, an order of magnitude larger than that of the X-ray nebula ($\\sim2\\;$pc). The association with SNR W41 suggests a common age of $\\sim5-100\\;$kyr, while its spin-down age is $4.9$~kyr. A small natal kick velocity may partly explain why a wind nebula was detected around this magnetar but not around other magnetars, most of which appear to have larger kick velocities and may have exited their birth SNR. We find that the GeV and TeV source detected by Fermi/LAT and H.E.S.S., respectively, of radius $\\sim11\\;$pc is most likely of hadronic origin. The dynamics and internal structure of the nebula are examined analytically to explain the nebula's current properties. Its size may n...

  19. Revised Diagnostic Diagrams for Planetary Nebulae

    CERN Document Server

    Riesgo, H

    2006-01-01

    Diagnostic diagrams of electron density - excitation for a sample of 613 planetary nebulae are presented. The present extensive sample allows the definition of new statistical limits for the distribution of planetary nebulae in the log [Ha/[SII

  20. The discovery of the "21" mu m and "30" mu m emission features in Planetary Nebulae with Wolf-Rayet central stars

    NARCIS (Netherlands)

    Hony, S; Waters, LBFM; Tielens, AGGM

    2001-01-01

    We report the discovery of the "21" mum and "30" mum features in the planetary nebulae around the hydrogen-deficient stars HD 826 and HD 158269. The carriers of these features are known to be produced in outflows around carbon-rich stars. This discovery demonstrates that the bulk of the dust in thes

  1. Energy exchanges in reconnection outflows

    Science.gov (United States)

    Lapenta, Giovanni; Goldman, Martin V.; Newman, David L.; Markidis, Stefano

    2017-01-01

    Reconnection outflows are highly energetic directed flows that interact with the ambient plasma or with flows from other reconnection regions. Under these conditions the flow becomes highly unstable and chaotic, as any flow jets interacting with a medium. We report here massively parallel simulations of the two cases of interaction between outflow jets and between a single outflow with an ambient plasma. We find in both case the development of a chaotic magnetic field, subject to secondary reconnection events that further complicate the topology of the field lines. The focus of the present analysis is on the energy balance. We compute each energy channel (electromagnetic, bulk, thermal, for each species) and find where the most energy is exchanged and in what form. The main finding is that the largest energy exchange is not at the reconnection site proper but in the regions where the outflowing jets are destabilized.

  2. Nordic Seas and Arctic Ocean CFC data in CARINA

    Directory of Open Access Journals (Sweden)

    E. Jeansson

    2009-10-01

    Full Text Available Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruises in the Arctic, Atlantic, and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon IN the Atlantic. The data have been subject to rigorous quality control (QC in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the data products, i.e. the three merged files with measured, calculated and interpolated values for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS, the Atlantic (ATL and the Southern Ocean (SO. The Arctic Mediterranean Seas is comprised of the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas.

    Here we present an overview of the QC of the CFC data for the Arctic Mediterranean Seas, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113, as well as carbon tetrachloride (CCl4. For the secondary QC of the CFCs we used a combination of tools, including the evaluation of depth profiles and CFC ratios, surface saturations and a crossover analysis. This resulted in a multiplicative adjustment of some cruise data, while some other cruises were flagged with questionable quality, which excluded them from the final data product.

  3. Protoplanetary disks in the hostile environment of Carina

    CERN Document Server

    Mesa-Delgado, A; Henney, W J; Puzia, T H; Tsamis, Y G

    2016-01-01

    We report the first direct imaging of protoplanetary disks in the star-forming region of Carina, the most distant, massive cluster in which disks have been imaged. Using the Atacama Large Millimeter/sub-millimeter Array (ALMA), disks are observed around two young stellar objects (YSOs) that are embedded inside evaporating gaseous globules and exhibit jet activity. The disks have an average size of 120 AU and total masses of 30 and 50 M_Jup. Given the measured masses, the minimum timescale required for planet formation (~1-2 Myr) and the average age of the Carina population (~1-4 Myr), it is plausible that young planets are present or their formation is currently ongoing in these disks. The non-detection of millimeter emission above the 4sigma threshold (~7 M_Jup) in the core of the massive cluster Trumpler~14, an area containing previously identified proplyd candidates, suggest evidence for rapid photo-evaporative disk destruction in the cluster's harsh radiation field. This would prevent the formation of gia...

  4. Spectroscopic and photometric observations of M supergiants in Carina.

    Science.gov (United States)

    Humphreys, R. M.; Strecker, D. W.; Ney, E. P.

    1972-01-01

    Spectroscopic study of 30 Southern-Hemisphere M supergiants mostly in Carina in the blue and near-infrared, and photometrical study of these stars from 0.4 to 18 microns. The uncertainties in the determinations of interstellar extinction are discussed, and the spatial distribution of the M supergiants in the Carina arm is shown. The presence of the 11-micron excess attributed to silicate dust is a common feature. Stars of the same spectral type and luminosity class are remarkably homogeneous in their long-wave behavior. The silicate feature becomes more prominent in the more luminous stars and in stars of later spectral type. Four composite systems show little long-wave excess. The two VV Cephei objects have excesses probably produced by gas emission, and the other two have little or no excess - supporting the suggestion that the presence of the early star prohibits the formation of a dust envelope. Three stars - VY CMa, VX Sgr, and HD 9767 - appear to be extreme examples of stars with large excesses over the entire long-wave region. It is suggested that these objects are surrounded by large amounts of particulate material over a great range of distances from the stars.

  5. Contraction of the solar nebula

    Science.gov (United States)

    Rawal, J. J.

    1984-10-01

    The concept of Roche limit is applied to the Laplacian theory of the origin of the solar system to study the contraction of a spherical gas cloud (solar nebula). In the process of contraction of the solar nebula, it is assumed that the phenomenon of supersonic turbulent convection described by Prentice (1978) is operative. It is found that the radius of the contracting solar nebula follows Titius-Bode law Rp = R_sun; ap, where R_sun; is the radius of the present Sun and a = 1.442. The consequences of the relation are also discussed. The aim, here, is an attempt to explain, on the basis of the concept of Roche limit, the distribution of planets in the solar system and try to understand the physics underlying it.

  6. XMM-Newton Detection of Hot Gas in Two Evolved Elliptical Planetary Nebulae: the Eskimo Nebula and the Ghost of Jupiter

    Science.gov (United States)

    Guerrero, M. A.; Chu, Y.-H.; Gruendl, R. A.; Meixner, M.

    2004-12-01

    Planetary nebulae (PNe) consist of the stellar material ejected by low- and intermediate-mass stars (1-8 M⊙) at the end of the asymptotic giant branch phase (AGB). As such a star evolves off the AGB phase, the copious mass-loss strips off the stellar envelope and exposes the hot stellar core that ionizes the nebular material. The central stars of PNe present fast stellar winds with terminal velocities 1000-4000 km s-1, while fast collimated outflows with velocities up to 1000 km s-1 are also observed in PNe. The interactions of the fast stellar wind and/or collimated outflows with nebular material can give rise to diffuse X-ray emission from PNe. Diffuse X-ray emission has been detected only in young PNe previously. To investigate the evolution of hot gas in PN interiors, we obtained XMM-Newton observations of NGC 2392 (the Eskimo Nebula) and NGC 3242 (the Ghost of Jupiter), two evolved elliptical PNe. Diffuse X-ray emission is detected in both nebulae. In both cases, the hot gas is confined within the innermost shell, the X-ray spectrum can be described by a thin plasma emission model with temperature ˜2×106 K, and the X-ray luminosity is ˜1×1031 ergs s-1. Furthermore, the X-ray spectrum of NGC 3242 shows evidence of enhanced nitrogen abundance, while the X-ray morphology of NGC 2392 hints a possible association with its fast collimated outflows.

  7. The ALMA Early Science View of FUor/EXor objects. II. The Very Wide Outflow Driven by HBC 494

    Science.gov (United States)

    Ruíz-Rodríguez, D.; Cieza, L. A.; Williams, J. P.; Tobin, J. J.; Hales, A.; Zhu, Z.; Mužić, K.; Principe, D.; Canovas, H.; Zurlo, A.; Casassus, S.; Perez, S.; Prieto, J. L.

    2017-01-01

    We present Atacama Large Millimeter/sub-millimeter Array (ALMA) Cycle-2 observations of the HBC 494 molecular outflow and envelope. HBC 494 is an FU Ori-like object embedded in the Orion A cloud and is associated with the reflection nebulae Re50 and Re50N. We use 12CO, 13CO and C18O spectral line data to independently describe the outflow and envelope structures associated with HBC 494. The moment-1 map of the 12CO emission shows the widest outflow cavities in a Class I object known to date (opening angle ˜ 150°). The morphology of the wide outflow is likely to be due to the interaction between winds originating in the inner disc and the surrounding envelope. The low-velocity blue- and red-shifted 13CO and C18O emission trace the rotation and infall motion of the circumstellar envelope. Using molecular line data and adopting standard methods for correcting optical depth effects, we estimate its kinematic properties, including an outflow mass on the order of 10-1 M⊙. Considering the large estimated outflow mass for HBC 494, our results support recent theoretical work suggesting that wind-driven processes might dominate the evolution of protoplanetary discs via energetic outflows.

  8. The ALMA early science view of FUor/EXor objects - II. The very wide outflow driven by HBC 494

    Science.gov (United States)

    Ruíz-Rodríguez, D.; Cieza, L. A.; Williams, J. P.; Tobin, J. J.; Hales, A.; Zhu, Z.; Mužić, K.; Principe, D.; Canovas, H.; Zurlo, A.; Casassus, S.; Perez, S.; Prieto, J. L.

    2017-04-01

    We present Atacama Large Millimeter/sub-millimeter Array Cycle-2 observations of the HBC 494 molecular outflow and envelope. HBC 494 is an FU Ori-like object embedded in the Orion A cloud and is associated with the reflection nebulae Re50 and Re50N. We use 12CO, 13CO and C18O spectral line data to independently describe the outflow and envelope structures associated with HBC 494. The moment-1 map of the 12CO emission shows the widest outflow cavities in a Class I object known to date (opening angle ∼150°). The morphology of the wide outflow is likely to be due to the interaction between winds originating in the inner disc and the surrounding envelope. The low-velocity blueshifted and redshifted 13CO and C18O emission trace the rotation and infall motion of the circumstellar envelope. Using molecular line data and adopting standard methods for correcting optical depth effects, we estimate its kinematic properties, including an outflow mass of the order of 10-1 M⊙. Considering the large estimated outflow mass for HBC 494, our results support recent theoretical work suggesting that wind-driven processes might dominate the evolution of protoplanetary discs via energetic outflows.

  9. A Magnetar Wind Nebula: the Spin-down-Powered Wind is not Enough

    Science.gov (United States)

    Gill, Ramandeep; Granot, Jonathan; Baring, Matthew G.; Gelfand, Joseph; Younes, George A.; Kargaltsev, Oleg; Kust Harding, Alice; Kouveliotou, Chryssa; Huppenkothen, Daniela

    2016-04-01

    Magnetars are a small class of slowly-rotating (P~2-12 s) highly magnetized (surface dipole fields ~10^{14}-10^{15} G) that show a variety of bursting activity, powered by the decay of their super-strong magnetic field. While many rotation-powered pulsars are surrounded by a pulsar wind nebula (PWN) powered by their spin-down MHD wind (the prime example being the Crab nebula), only now has the first magnetar wind nebula (MWN) been discovered in X-rays, around Swift J1834.9-0846. We have analyzed this system in detail to see what can be learned from it. We find good evidence that unlike normal PWNe, this MWN cannot be powered by its spin-down MHD wind alone. A considerable contribution to the MWN energy should come from a different source, most likely sporadic outflows associated with the magnetar's bursting activity. This suggests that the MWN may serve as a calorimeter, and provide a new and robust estimate for the magnetar's long-term mean energy output rate in outflows. We also discuss other interesting aspects of this system.

  10. The Lighthouse nebula: a run-away pulsar, its PWN, jets and parent SNR

    Science.gov (United States)

    Pavan, L.; Bordas, P.; Puhlhofer, G.; et al.

    2016-06-01

    Some 10-20 kyr ago a pulsar was born from a core collapse event, receiving right away a strong kick. Nowadays this pulsar is powering the Lighthouse Nebula (IGR J11014-6103): a complex system of outflows comprising the bow-shock PWN, and two well collimated jets extending perpendicularly to the pulsar's direction of motion. Whereas sharing some clear commonalities with the well known Guitar Nebula, the Lighthouse nebula is the only such system where the parent supernova remnant is well visible and bright in X-rays. I will describe the results from our recent Chandra X-ray campaign, and follow-up optical and radio observations, analyse the properties of the PWN, and possible interpretations on the nature of the long helicoidal jets and of the other outflows that we identified. I will also discuss the link between this system and its parent supernova remnant MSH 11-61A, which could help shedding a light on the processes that give birth to such peculiar systems.

  11. Emergence of a Quasar Outflow

    CERN Document Server

    Hamann, F; Hidalgo, P Rodriguez; Prochaska, J X; Herbert-Fort, S

    2008-01-01

    We report the first discovery of the emergence of a high-velocity broad-line outflow in a luminous quasar, J105400.40+034801.2 at redshift z ~ 2.1. The outflow is evident in ultraviolet CIV and SiIV absorption lines with velocity shifts v ~ 26,300 km/s and deblended widths FWHM ~ 4000 km/s. These features are marginally strong and broad enough to be considered broad absorption lines (BALs), but their large velocities exclude them from the standard BAL definition. The outflow lines appeared between two observations in the years 2002.18 and 2006.96. A third observation in 2008.48 showed the lines becoming ~40% weaker and 10% to 15% narrower. There is no evidence for acceleration or for any outflow gas at velocities 21.2 and average space density n_H > 2 x 10^5 cm^-3. We attribute the emergence of the outflow lines to a substantial flow structure moving across our line of sight, possibly near the ragged edge of the main BAL flow or possibly related to the onset of a BAL evolutionary phase.

  12. Outflow from Hot Accretion Flows

    CERN Document Server

    Yuan, Feng; Wu, Maochun

    2012-01-01

    Numerical simulations of hot accretion flows have shown that the mass accretion rate decreases with decreasing radius. Two models have been proposed to explain this result. In the adiabatic inflow-outflow solution (ADIOS), it is thought to be due to the loss of gas in outflows. In the convection-dominated accretion flow (CDAF) model, it is explained as because that the gas is locked in convective eddies. In this paper we use hydrodynamical (HD) and magnetohydrodynamical (MHD) simulations to investigate which one is physical. We calculate and compare various properties of inflow (gas with an inward velocity) and outflow (gas with an outward velocity). Systematic and significant differences are found. For example, for HD flows, the temperature of outflow is higher than inflow; while for MHD flows, the specific angular momentum of outflow is much higher than inflow. We have also analyzed the convective stability of MHD accretion flow and found that they are stable. These results suggest that systematic inward an...

  13. The Ejecta of Eta Carinae as Studied by STIS

    Science.gov (United States)

    Gull, Theodore R.; Oegerle, William R. (Technical Monitor)

    2002-01-01

    The Space Telescope Imaging Spectrograph has been used to study the emission and absorption spectra of ejecta surrounding Eta Carinae. Discussion will be presented on the overall structure of the Homunculus, the Weigelt blobs and the Strontium filament. Three visits have been accomplished with the Position Angle precisely the same and covering the Central Source and Weigelt Blobs B and D. Deep spectra have been done at several positions to obtain the overall velocity structure of the Homunculus and the disk region. Mapping has been done with the STIS medium dispersion gratings set near H beta and H alpha. We have obtained full coverage of the strontium filament from 1640 Angstroms to 10300 Angstroms. The structure and physical properties will be described.

  14. Detection of a Hot Binary Companion of $\\eta$ Carinae

    CERN Document Server

    Iping, R C; Gull, T R; Massa, D L; Hillier, D J; Iping, Rosina C.; Sonneborn, George; Gull, Theodore R.; Massa, Derck L.

    2005-01-01

    We report the detection of a hot companion of $\\eta$ Carinae using high resolution spectra (905 - 1180 \\AA) obtained with the Far Ultraviolet Spectroscopic Explorer (\\fuse) satellite. Observations were obtained at two epochs of the 2024-day orbit: 2003 June during ingress to the 2003.5 X-ray eclipse and 2004 April several months after egress. These data show that essentially all the far-UV flux from \\etacar shortward of \\lya disappeared at least two days before the start of the X-ray eclipse (2003 June 29), implying that the hot companion, \\etaB, was also eclipsed by the dense wind or extended atmosphere of \\etaA. Analysis of the far-UV spectrum shows that \\etaB is a luminous hot star. The \

  15. The Purple Haze of Eta Carinae: Binary-Induced Variability?

    CERN Document Server

    Smith, N; Collins, N R; Gull, T R; Smith, Nathan; Morse, Jon A.; Collins, Nicholas R.; Gull, Theodore R.

    2004-01-01

    Asymmetric variability in ultraviolet images of the Homunculus obtained with the Advanced Camera for Surveys/High Resolution Camera on the Hubble Space Telescope suggests that Eta Carinae is indeed a binary system. Images obtained before, during, and after the recent ``spectroscopic event'' in 2003.5 show alternating patterns of bright spots and shadows on opposite sides of the star before and after the event, providing a strong geometric argument for an azimuthally-evolving, asymmetric UV radiation field as one might predict in some binary models. The simplest interpretation of these UV images, where excess UV escapes from the secondary star in the direction away from the primary, places the major axis of the eccentric orbit roughly perpendicular to our line of sight, sharing the same equatorial plane as the Homunculus, and with apastron for the hot secondary star oriented toward the southwest of the primary. However, other orbital orientations may be allowed with more complicated geometries. Selective UV il...

  16. The -145 km/S Absorption System of Eta Carinae

    Science.gov (United States)

    Vieira, G.; Gull, T. R.; Danks, A.; Johansson, S.

    2002-01-01

    With the STIS E230H mode (R-118,000) , we have identified about twenty absorption components in line of sight from Eta Carinae. Two components, one at -513 km/s and another at -145 W s , are quite different in character from the others, mostly at intermediate velocities. The -145 km/s component is significantly wider in fwhm, is seen in many more species, and the lower level can be above 20,000/cm, well above the 2000/cm noted in the -513 km/s component. In the spectral region from 2400 to 3160A, approximately 500 absorption lines have been identified. In this poster, we will present line identifications and atomic parameters of the measured lines, hopefully providing insight as to what levels are being excited and by what processes.

  17. Geminga’s Puzzling Pulsar Wind Nebula

    Science.gov (United States)

    Posselt, B.; Pavlov, G. G.; Slane, P. O.; Romani, R.; Bucciantini, N.; Bykov, A. M.; Kargaltsev, O.; Weisskopf, M. C.; Ng, C.-Y.

    2017-01-01

    We report on six new Chandra observations of the Geminga pulsar wind nebula (PWN). The PWN consists of three distinct elongated structures—two ≈ 0.2{d}250 pc long lateral tails and a segmented axial tail of ≈ 0.05{d}250 pc length, where {d}250=d/(250 {pc}). The photon indices of the power-law spectra of the lateral tails, {{Γ }}≈ 1, are significantly harder than those of the pulsar ({{Γ }}≈ 1.5) and the axial tail ({{Γ }}≈ 1.6). There is no significant diffuse X-ray emission between the lateral tails—the ratio of the X-ray surface brightness between the south tail and this sky area is at least 12. The lateral tails apparently connect directly to the pulsar and show indications of moving footpoints. The axial tail comprises time-variable emission blobs. However, there is no evidence for constant or decelerated outward motion of these blobs. Different physical models are consistent with the observed morphology and spectra of the Geminga PWN. In one scenario, the lateral tails could represent an azimuthally asymmetric shell whose hard emission is caused by the Fermi acceleration mechanism of colliding winds. In another scenario, the lateral tails could be luminous, bent polar outflows, while the blobs in the axial tail could represent a crushed torus. In a resemblance to planetary magnetotails, the blobs of the axial tail might also represent short-lived plasmoids, which are formed by magnetic field reconnection in the relativistic plasma of the pulsar wind tail.

  18. Molecular Outflows: Explosive versus Protostellar

    Science.gov (United States)

    Zapata, Luis A.; Schmid-Burgk, Johannes; Rodríguez, Luis F.; Palau, Aina; Loinard, Laurent

    2017-02-01

    With the recent recognition of a second, distinctive class of molecular outflows, namely the explosive ones not directly connected to the accretion–ejection process in star formation, a juxtaposition of the morphological and kinematic properties of both classes is warranted. By applying the same method used in Zapata et al., and using 12CO(J = 2-1) archival data from the Submillimeter Array, we contrast two well-known explosive objects, Orion KL and DR21, to HH 211 and DG Tau B, two flows representative of classical low-mass protostellar outflows. At the moment, there are only two well-established cases of explosive outflows, but with the full availability of ALMA we expect that more examples will be found in the near future. The main results are the largely different spatial distributions of the explosive flows, consisting of numerous narrow straight filament-like ejections with different orientations and in almost an isotropic configuration, the redshifted with respect to the blueshifted components of the flows (maximally separated in protostellar, largely overlapping in explosive outflows), the very-well-defined Hubble flow-like increase of velocity with distance from the origin in the explosive filaments versus the mostly non-organized CO velocity field in protostellar objects, and huge inequalities in mass, momentum, and energy of the two classes, at least for the case of low-mass flows. Finally, all the molecular filaments in the explosive outflows point back to approximately a central position (i.e., the place where its “exciting source” was located), contrary to the bulk of the molecular material within the protostellar outflows.

  19. INTEGRAL FIELD SPECTROSCOPY OF AGN ABSORPTION OUTFLOWS: MRK 509 AND IRAS F04250–5718

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guilin; Arav, Nahum [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Rupke, David S. N., E-mail: glliu@vt.edu [Department of Physics, Rhodes College, Memphis, TN 38112 (United States)

    2015-11-15

    Ultraviolet (UV) absorption lines provide abundant spectroscopic information enabling the probe of the physical conditions in active galactic nucleus (AGN) outflows, but the outflow radii (and the energetics consequently) can only be determined indirectly. We present the first direct test of these determinations using integral field unit (IFU) spectroscopy. We have conducted Gemini IFU mapping of the ionized gas nebulae surrounding two AGNs, whose outflow radii have been constrained by UV absorption line analyses. In Mrk 509, we find a quasi-spherical outflow with a radius of 1.2 kpc and a velocity of ∼290 km s{sup −1}, while IRAS F04250–5718 is driving a biconical outflow extending out to 2.9 kpc, with a velocity of ∼580 km s{sup −1} and an opening angle of ∼70°. The derived mass flow rate ∼5 and >1 M{sub ⊙} yr{sup −1}, respectively, and the kinetic luminosity ≳1 × 10{sup 41} erg s{sup −1} for both. Adopting the outflow radii and geometric parameters measured from IFU, absorption line analyses would yield mass flow rates and kinetic luminosities in agreement with the above results within a factor of ∼2. We conclude that the spatial locations, kinematics, and energetics revealed by this IFU emission-line study are consistent with pre-existing UV absorption line analyses, providing a long-awaited direct confirmation of the latter as an effective approach for characterizing outflow properties.

  20. H$_2$ in low-ionization structures of planetary nebulae

    CERN Document Server

    Akras, Stavros; Ramos-Larios, Gerardo

    2016-01-01

    We report the detection of near-IR H$_2$ emission from the low-ionization structures (knots) in two planetary nebulae. The deepest ever, high-angular resolution H$_2$ 1-0 S(1) at 2.122$\\mu$, H$_2$ 2-1 S(1) at 2.248$\\mu$ and Br$\\gamma$ images of K 4-47 and NGC 7662, obtained using the Near InfraRed Imager and Spectrometer (NIRI) at Gemini-North, are analyzed here. K 4-47 reveals a remarkable highly collimated bipolar structure not only in the optical but also in the molecular hydrogen emission. The H$_2$ emission emanates from the walls of the bipolar outflows and also from the pair of knots at the tip of the outflows. The H$_2$ 1-0 S(1)/2-1 S(1) line ratio ranges from ~7 to ~10 suggesting the presence of shock interactions. Our findings can be explained by the interaction of a jet/bullet ejected from the central star with the surrounding asymptotic giant branch material. The strongest H$_2$ line, v=1-0 S(1) is also detected in several low-ionization knots located at the periphery of the elliptical planetary n...

  1. Knowledge Outflows from Foreign Subsidiaries

    DEFF Research Database (Denmark)

    Perri, Alessandra; Andersson, Ulf

    the value of the subsidiary’s knowledge stock is very high, the need for knowledge protection restrains reciprocity mechanisms in knowledge exchanges, thus reducing the extent of knowledge outflows to the host location. This study contributes to the literature on the firm-level antecedents of FDI...

  2. Protostellar Outflows in L1340

    CERN Document Server

    Walawender, Josh; Smutko, Michael; O'Linger-Luscusk, JoAnn; Moriarty-Schieven, Gerald

    2016-01-01

    We have searched the L1340 A, B, and C clouds for shocks from protostellar outflows using the H$_2$ 2.122 $\\mu$m near-IR line as a shock tracer. Substantial outflow activity has been found in each of the three regions of the cloud (L1340 A, L1340 B, & L1340 C). We find 42 distinct shock complexes (16 in L1340 A, 11 in L1340 B, and 15 in L1340 C). We were able to link 17 of those shock complexes in to 12 distinct outflows and identify candidate source stars for each. We examine the properties (A$_{V}$, T$_{bol}$, and L$_{bol}$) of the source protostars and compare that to the properties of the general population of Class 0/I and flat SED protostars and find that there is an indication, albeit at low statistical significance, that the outflow driving protostars are drawn from a population with lower A$_{V}$, higher L$_{bol}$, and lower T$_{bol}$ than the general population of protostars.

  3. Molecular outflows in starburst nuclei

    CERN Document Server

    Roy, Arpita; Sharma, Prateek; Shchekinov, Yuri

    2016-01-01

    Recent observations have detected molecular outflows in a few nearby starburst nuclei. We discuss the physical processes at work in such an environment in order to outline a scenario that can explain the observed parameters of the phenomenon, such as the molecular mass, speed and size of the outflows. We show that outflows triggered by OB associations, with $N_{OB}\\ge 10^5$ (corresponding to a star formation rate (SFR)$\\ge 1$ M$_{\\odot}$ yr$^{-1}$ in the nuclear region), in a stratified disk with mid-plane density $n_0\\sim 200\\hbox{--}1000$ cm$^{-3}$ and scale height $z_0\\ge 200 (n_0/10^2 \\, {\\rm cm}^{-3})^{-3/5}$ pc, can form molecules in a cool dense and expanding shell. The associated molecular mass is $\\ge 10^7$ M$_\\odot$ at a distance of a few hundred pc, with a speed of several tens of km s$^{-1}$. We show that a SFR surface density of $10 \\le \\Sigma_{SFR} \\le 50$ M$_\\odot$ yr$^{-1}$ kpc$^{-2}$ favours the production of molecular outflows, consistent with observed values.

  4. Constraining the Absolute Orientation of eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] Emission

    Science.gov (United States)

    Madura, T. I.; Gull, T. R.; Owocki, S. P.; Groh, J. H.; Okazaki, A. T.; Russell, C. M. P.

    2011-01-01

    We present a three-dimensional (3-D) dynamical model for the broad [Fe III] emission observed in Eta Carinae using the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS). This model is based on full 3-D Smoothed Particle Hydrodynamics (SPH) simulations of Eta Car's binary colliding winds. Radiative transfer codes are used to generate synthetic spectro-images of [Fe III] emission line structures at various observed orbital phases and STIS slit position angles (PAs). Through a parameter study that varies the orbital inclination i, the PA(theta) that the orbital plane projection of the line-of-sight makes with the apastron side of the semi-major axis, and the PA on the sky of the orbital axis, we are able, for the first time, to tightly constrain the absolute 3-D orientation of the binary orbit. To simultaneously reproduce the blue-shifted emission arcs observed at orbital phase 0.976, STIS slit PA = +38deg, and the temporal variations in emission seen at negative slit PAs, the binary needs to have an i approx. = 130deg to 145deg, Theta approx. = -15deg to +30deg, and an orbital axis projected on the sky at a P A approx. = 302deg to 327deg east of north. This represents a system with an orbital axis that is closely aligned with the inferred polar axis of the Homunculus nebula, in 3-D. The companion star, Eta(sub B), thus orbits clockwise on the sky and is on the observer's side of the system at apastron. This orientation has important implications for theories for the formation of the Homunculus and helps lay the groundwork for orbital modeling to determine the stellar masses.

  5. A Starfish Preplanetary Nebula: IRAS 19024+0044

    Science.gov (United States)

    Sahai, Raghvendra; Sanchez Contreras, Carmen; Morris, Mark

    2005-01-01

    Using the Hubble Space Telescope, we have imaged the OH/IR star IRAS 19024+0044 (I19024) at 0.6, 0.8, 1.1, and 1.6 micrometers, as part of our surveys of candidate preplanetary nebulae. The images show a multipolar nebula of size approximately equal to 3.'7 2.'3, with at least six elongated lobes emanating from the center of the nebula. Two of the lobes show limb-brightened tips having point-symmetric structure with respect to the expected location of the central star. The central region shows two dark bands southwest and northeast of a central shallow maximum that may be either two inclined dusty toroidal structures or the dense parts of a single wide, inhomogeneous, toroid. Avery faint, surface brightness-limited, diffuse halo surrounds the lobes. Long-slit/echelle optical spectroscopy obtained at the Mount Palomar and Keck observatories shows a spatially compact source of H(alpha) emission; the H(alpha) line shows a strong, narrow, central core with very broad (+/-1000 km/sec), weak wings, and a narrower blueshifted absorption feature signifying the presence of an approximately 100 km/sec(exp -1) outflow. The spectrum is characterized by a strong, relatively featureless, continuum and lacks the strong forbidden emission lines characteristic of planetary nebulae, confirming that IRAS 19024 is a preplanetary nebula; the spectral type for the central star, although uncertain, is most likely early G. Interferometric observations of the CO J = 1 -0 line emission with the Owens Valley Radio Interferometer show a marginally resolved molecular envelope (size 5.'5 x 4.'4) with an expansion velocity of 13 km/sec (exp -1), resulting from the asymptotic giant branch (AGB) progenitor's dense, slow wind. We derive a kinematic distance of 3.5 kpc to I19024, based on its radial velocity. The bolometric flux is 7:3 x 10(exp -9) erg s(exp -1) cm(exp -2), and the luminosity 2850 L. The relatively low luminosity of I19024, in comparison with stellar evolutionary models, indicates

  6. Irradiated Interfaces in the Ara OB1, Carina, Eagle Nebula, and Cyg OB2 Massive Star Formation Regions

    CERN Document Server

    Hartigan, P; Cleeves, L I

    2013-01-01

    Regions of massive star formation offer some of the best and most easily-observed examples of radiation hydrodynamics. Boundaries where fully-ionized H II regions transition to neutral/molecular photodissociation regions (PDRs) are of particular interest because marked temperature and density contrasts across the boundaries lead to evaporative flows and fluid dynamical instabilities that can evolve into spectacular pillar-like structures. When detached from their parent clouds, pillars become ionized globules that often harbor one or more young stars. H2 molecules at the interface between a PDR and an H II region absorb ultraviolet light from massive stars, and the resulting fluoresced infrared emission lines are an ideal way to trace this boundary independent of obscuring dust. This paper presents H2 images of four regions of massive star formation that illustrate different types of PDR boundaries. The Ara OB1 star formation region contains a striking long wall that has several wavy structures which are pres...

  7. Outflow forces in intermediate mass star formation

    CERN Document Server

    van Kempen, T A; van Dishoeck, E F; Kristensen, L E; Belloche, A; Klaassen, P D; Leurini, S; Jose-Garcia, I San; Aykutalp, A; Choi, Y; Endo, A; Frieswijk, W; Harsono, D; Karska, A; Koumpia, E; van der Marel, N; Nagy, Z; Perez-Beaupuits, J P; Risacher, C; van Weeren, R J; Wyrowski, F; Yildiz, U A; Guesten, R; Boland, W; Baryshev, A

    2015-01-01

    Intermediate mass protostarsprovide a bridge between theories of low- and high-mass star formation. Emerging molecular outflows can be used to determine the influence of fragmentation and multiplicity on protostellar evolution through the correlation of outflow forces of intermediate mass protostars with the luminosity. The aim of this paper is to derive outflow forces from outflows of six intermediate mass protostellar regions and validate the apparent correlation between total luminosity and outflow force seen in earlier work, as well as remove uncertainties caused by different methodology. By comparing CO 6--5 observations obtained with APEX with non-LTE radiative transfer model predictions, optical depths, temperatures, densities of the gas of the molecular outflows are derived. Outflow forces, dynamical timescales and kinetic luminosities are subsequently calculated. Outflow parameters, including the forces, were derived for all sources. Temperatures in excess of 50 K were found for all flows, in line wi...

  8. Molecular studies of Planetary Nebulae

    CERN Document Server

    Zhang, Yong

    2016-01-01

    Circumstellar envelopes (CEs) around evolved stars are an active site for the production of molecules. After evolving through the Asymptotic Giant Branch (AGB), proto-planetary nebula (PPN), to planetary nebula (PN) phases, CEs ultimately merge with the interstellar medium (ISM). The study of molecules in PNe, therefore, is essential to understanding the transition from stellar to interstellar materials. So far, over 20 molecular species have been discovered in PNe. The molecular composition of PNe is rather different from those of AGB and PPNe, suggesting that the molecules synthesized in PN progenitors have been heavily processed by strong ultraviolet radiation from the central star. Intriguingly, fullerenes and complex organic compounds having aromatic and aliphatic structures can be rapidly formed and largely survive during the PPN/PN evolution. The similar molecular compositions in PNe and diffuse clouds as well as the detection of C$_{60}^+$ in the ISM reinforce the view that the mass-loss from PNe can ...

  9. The western Veil nebula (Image)

    Science.gov (United States)

    Glenny, M.

    2009-12-01

    The western Veil nebula in Cygnus. 15-part mosaic by Mike Glenny, Gloucestershire, taken over several months mostly in the autumn of 2008. 200mm LX90/f10 autoguided, Meade UHC filter, 0.3xFR/FF, Canon 20Da DSLR. Exposures each typically 10x360 secs at ISO1600, processed in Registax4, PixInsight (for flat field correction) & Photoshop CS.

  10. Gallery of Planetary Nebula Spectra

    CERN Document Server

    Kwitter, K B; Kwitter, Karen B.; Henry, Richard B.C.

    2006-01-01

    We present the Gallery of Planetary Nebula Spectra now available at http://oitwilliams.edu/nebulae. The website offers high-quality, moderate resolution (~7-10 A FWHM) spectra of 128 Galactic planetary nebulae from 3600-9600 A, obtained by Kwitter, Henry, and colleagues with the Goldcam spectrograph at the KPNO 2.1-m or with the RC spectrograph at the CTIO 1.5-m. The master PN table contains atlas data and an image link. A selected object's spectrum is displayed in a zoomable window; line identification templates are provided. In addition to the spectra themselves, the website also contains a brief discussion of PNe as astronomical objects and as contributors to our understanding of stellar evolution. We envision that this website, which concentrates a large amount of data in one place, will be of interest to a variety of users: researchers might need to check the spectrum of a particular object of interest; the non-specialist astronomer might simply be interested in perusing such a collection of spectra; and...

  11. HH 223: a parsec-scale H2 outflow in the star-forming region L723

    CERN Document Server

    Lopez, R; Gomez, G; Estalella, R; Carrasco-Gonzalez, C

    2010-01-01

    The dark cloud Lynds 723 (L723) is a low-mass star-forming region where one of the few known cases of a quadrupolar CO outflow has been reported. Two recent works have found that the radio continuum source VLA 2, towards the centre of the CO outflow, is actually a multiple system of young stellar objects (YSOs). Several line-emission nebulae that lie projected on the east-west CO outflow were detected in narrow-band Halpha and [SII] images. The spectra of the knots are characteristic of shock-excited gas (Herbig-Haro spectra), with supersonic blueshifted velocities, which suggests an optical outflow also powered by the VLA 2 YSO system of L723. We imaged a field of ~5' X 5' centred on HH 223, which includes the whole region of the quadrupolar CO outflow with nir narrow-band filters . The H2 line-emission structures appear distributed over a region of 5.5' (0.5 pc for a distance of 300 pc) at both sides of the VLA 2 YSO system, with an S-shape morphology, and are projected onto the east-west CO outflow. Most o...

  12. Shining A Light On Galactic Outflows: Photo-Ionized Outflows

    CERN Document Server

    Chisholm, John; Leitherer, Claus; Chen, Yanmei; Wofford, Aida

    2016-01-01

    We study the ionization structure of galactic outflows in 37 nearby, star forming galaxies with the Cosmic Origins Spectrograph on the Hubble Space Telescope. We use the O I, Si II, Si III, and Si IV ultraviolet absorption lines to characterize the different ionization states of outflowing gas. We measure the equivalent widths, line widths, and outflow velocities of the four transitions, and find shallow scaling relations between them and galactic stellar mass and star formation rate. Regardless of the ionization potential, lines of similar strength have similar velocities and line widths, indicating that the four transitions can be modeled as a co-moving phase. The Si equivalent width ratios (e.g. Si IV/Si II) have low dispersion, and little variation with stellar mass; while ratios with O I and Si vary by a factor of 2 for a given stellar mass. Photo-ionization models reproduce these equivalent width ratios, while shock models under predict the relative amount of high ionization gas. The photo-ionization mo...

  13. Modelagem do vento e da fotosfera de AG Carinae

    Science.gov (United States)

    Groh, J. H.; Damineli, A.

    2003-08-01

    A trajetória evolutiva das estrelas de alta massa depende fortemente de suas taxas de perda de massa. Apesar do rápido progresso no estudo destas estrelas, a taxa de perda de massa e outros parâmetros físicos básicos, como a temperatura superficial e a velocidade terminal do vento ainda não estão bem determinados. Isto ocorre devido à presença de ventos irregulares, rápidos e fortes ao redor destas estrelas, tornando a interpretação dos seus espectros uma tarefa difícil. Assim, a modelagem do vento e da fotosfera dessas estrelas está sendo cada vez mais usada para obter tais parâmetros a partir dos espectros. O aumento da taxa de perda de massa durante a fase LBV (Variáveis Luminosas Azuis), comparado com outros tipos de estrelas, tem sido atribuído a instabilidades do tipo S Doradus. Dispomos de uma base de dados espectroscópicos cobrindo 22 anos de observações de AG Carinae, incluindo um ciclo S Doradus completo, com espectros CCD em alta resolução na faixa óptica e infravermelha. Utilizamos o programa desenvolvido por Schmutz (1997) para uma análise preliminar desse ciclo, obtendo a taxa de perda de massa a partir da linha do Ha. Não existe uma correlação clara da taxa de perda de massa com mudanças da temperatura efetiva, do raio da estrela e do fluxo na banda V. A estrela atingiu seu mínimo fotométrico (raio mínimo) em 1990 e o máximo fotométrico (raio máximo) em 1995, enquanto que o fluxo máximo da linha do Ha ocorreu em 1996. Além disso a taxa de perda de massa não segue esse ciclo, contrariamente às idéias correntes. Para fazer um modelo mais realista estamos usando o programa CMFGEN (Hillier & Miller), que trata a fotosfera e o vento estelar de forma consistente, considerando a radiação fora do equilíbrio termodinâmico (NLTE) e com blanketting total de linhas. Simulamos o espectro de AG Carinae em duas épocas extremas do ciclo S Dor para testar os resultados obtidos com o modelo mais simplificado.

  14. LIGHT ECHOES FROM η CARINAE'S GREAT ERUPTION: SPECTROPHOTOMETRIC EVOLUTION AND THE RAPID FORMATION OF NITROGEN-RICH MOLECULES

    Energy Technology Data Exchange (ETDEWEB)

    Prieto, J. L.; Knapp, G. R. [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 (United States); Rest, A.; Walborn, N. R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bianco, F. B. [Department of Physics, New York University, New York, NY 10012 (United States); Matheson, T. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Smith, N. [Steward Observatory, University of Arizona, Tucson, Arizona 85721 (United States); Hsiao, E. Y.; Campillay, A.; Contreras, C.; González, C.; Morrell, N.; Phillips, M. M. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Chornock, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Paredes Álvarez, L.; James, D.; Smith, R. C. [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Kunder, A. [Leibniz-Institut für Astrophysik Potsdam, an der Sternwarte 16, D-14482, Potsdam (Germany); Margheim, S. [Gemini Observatory, Southern Operations Center, Casilla 603, La Serena (Chile); Welch, D. L. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); and others

    2014-05-20

    We present follow-up optical imaging and spectroscopy of one of the light echoes of η Carinae's nineteenth century Great Eruption discovered by Rest et al. By obtaining images and spectra at the same light echo position between 2011 and 2014, we follow the evolution of the Great Eruption on a 3 yr timescale. We find remarkable changes in the photometric and spectroscopic evolution of the echo light. The i-band light curve shows a decline of ∼0.9 mag in ∼1 yr after the peak observed in early 2011 and a flattening at later times. The spectra show a pure-absorption early G-type stellar spectrum at peak, but a few months after peak the lines of the Ca II triplet develop strong P-Cygni profiles and we see the appearance of [Ca II] 7291, 7324 doublet in emission. These emission features and their evolution in time resemble those observed in the spectra of some Type IIn supernovae and supernova impostors. Most surprisingly, starting ∼300 days after peak brightness, the spectra show strong molecular transitions of CN at ≳ 6800 Å. The appearance of these CN features can be explained if the ejecta are strongly nitrogen enhanced, as is observed in modern spectroscopic studies of the bipolar Homunculus nebula. Given the spectroscopic evolution of the light echo, velocities of the main features, and detection of strong CN, we are likely seeing ejecta that contributes directly to the Homunculus nebula.

  15. Silicon Monoxide Observations Reveal a Cluster of Hidden Compact Outflows in the OMC1 South Region

    CERN Document Server

    Zapata, L A; Rodríguez, L F; O'Dell, C R; Zhang, Q; Muench, A; Zapata, Luis A.; Ho, Paul T. P.; Rodriguez, Luis F.; Zhang, Qizhou; Muench, August

    2006-01-01

    We present high angular resolution ($2\\rlap.{''}8 \\times 1\\rlap.{''}7$) SiO J=5$\\to$4; $v=0$ line observations of the OMC1S region in the Orion Nebula made using the Submillimeter Array (SMA). We detect for the first time a cluster of four compact bipolar and monopolar outflows that show high, moderate and low velocity gas and appear to be energized by millimeter and infrared sources associated with this region. The SiO molecular outflows are compact ($<$ 3500 AU), and in most of the cases, they are located very close to their exciting sources. We thus propose that the SiO thermal emission is tracing the youngest and most highly excited parts of the outflows which cannot be detected by other molecules. Moreover, since the ambient cloud is weak in the SiO line emission, these observations can reveal flows that in other molecular transitions will be confused with the ambient velocity cloud emission. Analysis of their positional-velocity diagrams show that some components of these outflows may be driven by wi...

  16. Outflow dynamics of dust-driven wind models and implications for cool envelopes of PNe

    CERN Document Server

    Verbena, J L; Wachter, A

    2011-01-01

    The density profiles of cool envelopes of young Planetary Nebulae (PNe) are reminiscent of the final AGB outflow history of the central star, so far as these have not yet been transformed by the hot wind and radiation of the central star. Obviously, the evolution of the mass loss rate of that dust-driven, cool wind of the former giant in its final AGB stages must have shaped these envelopes to some extent. Less clear is the impact of changes in the outflow velocity. Certainly, larger and fast changes would lead to significant complications in the reconstruction of the mass-loss history from a cool envelope's density profile. Here, we analyse the outflow velocity v_{\\rm exp} in a consistent set of over 50 carbon-rich, dust-driven and well "saturated" wind models, and how it depends on basic stellar parameters. We find a relation of the kind of v_{\\rm exp} \\propto (L/M)^{0.6}. By contrast to the vast changes of the mass-loss rate in the final outflow phase, this relation suggest only very modest variations in t...

  17. A low pre-infall mass for the Carina dwarf galaxy from disequilibrium modelling

    CERN Document Server

    Ural, Uğur; Read, Justin I; Walker, Matthew G

    2015-01-01

    Dark matter only simulations of galaxy formation predict many more subhalos around a Milky Way like galaxy than the number of observed satellites. Proposed solutions require the satellites to inhabit dark matter halos with masses between one to ten billion solar masses at the time they fell into the Milky Way. Here we use a modelling approach, independent of cosmological simulations, to obtain a preinfall mass of 360 (+380,-230) million solar masses for one of the Milky Way's satellites: Carina. This determination of a low halo mass for Carina can be accommodated within the standard model only if galaxy formation becomes stochastic in halos below ten billion solar masses. Otherwise Carina, the eighth most luminous Milky Way dwarf, would be expected to inhabit a significantly more massive halo. The implication of this is that a population of "dark dwarfs" should orbit the Milky Way: halos devoid of stars and yet more massive than many of their visible counterparts.

  18. Hot Outflows in Galaxy Clusters

    CERN Document Server

    Kirkpatrick, C C

    2015-01-01

    The gas-phase metallicity distribution has been analyzed for the hot atmospheres of 29 galaxy clusters using {\\it Chandra X-ray Observatory} observations. All host brightest cluster galaxies (BCGs) with X-ray cavity systems produced by radio AGN. We find high elemental abundances projected preferentially along the cavities of 16 clusters. The metal-rich plasma was apparently lifted out of the BCGs with the rising X-ray cavities (bubbles) to altitudes between twenty and several hundred kiloparsecs. A relationship between the maximum projected altitude of the uplifted gas (the "iron radius") and jet power is found with the form $R_{\\rm Fe} \\propto P_{\\rm jet}^{0.45}$. The estimated outflow rates are typically tens of solar masses per year but exceed $100 ~\\rm M_\\odot ~yr^{-1}$ in the most powerful AGN. The outflow rates are 10% to 20% of the cooling rates, and thus alone are unable to offset a cooling inflow. Nevertheless, hot outflows effectively redistribute the cooling gas and may play a significant role at ...

  19. Eta Carinae: At the Crossroads of becoming a Supernova

    Science.gov (United States)

    Gull, Theodore

    2007-01-01

    Since the 1840's, when Eta Carinae's visual magnitude rivaled Sirius, the brightest star in the night sky, astronomers have wondered what major event took place. Today with the Hubble Space Telescope Imaging Spectrograph, with CHANDRA X-ray spectroscopy and the Very Large Telescope spectrographs and interferometers, we have learned that over 12 solar masses of material was ejected at 500 to 700 km/s into interstellar space. This ejecta is quite different from the normal interstellar medium. It is rich in nitrogen, poor in oxygen and carbon. The dust properties are quite peculiar and many metals such as vanadium, strontium, cadmium are seen in both absorption against the central source, plus a number of molecules. The chemical and dust formation is likely dominated by nitrogen as we see H_2, CH, CH+, OH, NH, HCl and NH-3, but no CO. Other metals and molecules are being searched out in the FUSE, HST/STIS, VLT/UVES and VLT/CRIRES spectra. I will describe what we know about the massive binary stellar system, how it changes every 5.54 year in UV and X-ray output and how the massive ejecta responds in this astrophysical laboratory.

  20. A multispectral view of the periodic events in eta Carinae

    CERN Document Server

    Damineli, A; Corcoran, M F; Stahl, O; Groh, J H; Arias, J; Teodoro, M; Morrell, N; Gamen, R; Gonzalez, F; Leister, N V; Levato, H; Levenhagen, R S; Grosso, M; Colombo, J F Albacete; Wallerstein, G

    2007-01-01

    A full description of the 5.5-yr low excitation events in eta Carinae is presented. We show that they are not simple and brief, as thought before, but a combination of two components. The first, the `slow variation' component, is revealed by slow changes in the ionization level of circumstellar matter across the whole cycle and is caused by the gradual immersion of the secondary star in the wind of the primary. The second, the `collapse' component, is restricted to some months around the minimum, and is due to the immersion of the secondary deep in the primary wind. During this stage there is a general collapse of the wind-wind collision shock, and the Weigelt blobs are strongly shielded from high energy photons (E > 16 eV). High energy phenomena are sensitive only to the `collapse', low energy only to the `slow variation' and that of intermediate energy to both components. Simple eclipses and mechanisms effective only near periastron (e.g., shell ejection or accretion onto the secondary star) cannot account ...

  1. Accretion at the periastron passage of Eta Carinae

    CERN Document Server

    Kashi, Amit

    2016-01-01

    We present high resolution numerical simulations of the colliding wind system $\\eta$ Carinae, showing accretion onto the secondary star close to periastron passage. Our hydrodynamical simulations include self gravity and radiative cooling. The smooth stellar winds collide and develop instabilities, mainly the non-linear thin shell instability, and form filaments and clumps. We find that a few days before periastron passage the dense filaments and clumps flow towards the secondary as a result of its gravitational attraction, and reach the zone where we inject the secondary wind. We run our simulations for the conventional stellar masses, $M_1=120 ~\\rm{M_\\odot}$ and $M_2=30 ~\\rm{M_\\odot}$, and for a high mass model, $M_1=170 ~\\rm{M_\\odot}$ and $M_2=80 ~\\rm{M_\\odot}$, that was proposed to better fit the history of giant eruptions. As expected, the simulations results show that the accretion processes is more pronounced for a more massive secondary star.

  2. Planetary nebulae abundances and stellar evolution

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.

    2006-01-01

    A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are the same as HII regions and early type star abundance gradi

  3. Planetary nebulae abundances and stellar evolution II

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.

    2010-01-01

    Context. In recent years mid-and far infrared spectra of planetary nebulae have been analysed and lead to more accurate abundances. It may be expected that these better abundances lead to a better understanding of the evolution of these objects. Aims. The observed abundances in planetary nebulae are

  4. Using Planetary Nebulae to Teach Physics

    Science.gov (United States)

    Kwitter, Karen B.

    2011-05-01

    We have developed an interactive website, "Gallery of Planetary Nebula Spectra," (www.williams.edu/Astronomy/research/PN/nebulae/) that contains high-quality optical-to-near-infrared spectra, atlas information, and bibliographic references for more than 160 planetary nebulae that we have observed in the Milky Way Galaxy. To make the material more accessible to students, I have created three undergraduate-level exercises that explore physics-related aspects of planetary nebulae. "Emission Lines and Central Star Temperature” uses the presence or absence of emission lines from species with different ionization potentials to rank the temperatures of the exciting stars in a selection of nebulae. "Interstellar Reddening” uses the observed Balmer decrement in a sample of planetary nebulae at different Galactic latitudes to infer the distribution of interstellar dust in the Milky Way. Finally, "Determining the Gas Density in Planetary Nebulae,” which I will focus on here, uses the observed intensity ratio of the 6717 Å and 6731 Å emission lines from singly ionized sulfur to determine the electron density in the nebular gas. These exercises demonstrate that planetary nebula spectra are useful real-world examples illustrating a variety of physical principles, including the behavior of blackbodies, wavelength-dependent particle scattering, recombination-line ratios, atomic physics, and statistical mechanics.

  5. On the nature of the prototype LBV AG Carinae I. Fundamental parameters during visual minimum phases and changes in the bolometric luminosity during the S-Dor cycle

    CERN Document Server

    Groh, Jose H; Damineli, Augusto; Whitelock, Patricia A; Marang, Fred; Rossi, C

    2009-01-01

    We present a detailed spectroscopic analysis of the luminous blue variable AG Carinae during the last two visual minimum phases of its S-Dor cycle (1985-1990 and 2000-2003). The analysis reveals an overabundance of He, N, and Na, and a depletion of H, C, and O, on the surface of AG Car, indicating the presence of CNO-processed material. Furthermore, the ratio N/O is higher on the stellar surface than in the nebula. We found that the minimum phases of AG Car are not equal to each other, since we derived a noticeable difference between the maximum effective temperature achieved during 1985-1990 (22,800 K) and 2000-2001 (17,000 K). While the wind terminal velocity was 300 km/s in 1985-1990, it was as low as 105 km/s in 2001. The mass-loss rate, however, was lower from 1985-1990 (1.5 x 10^(-5) Msun/yr) than from 2000-2001 (3.7 x 10^(-5) Msun/yr). We found that the wind of AG Car is significantly clumped (f=0.10 - 0.25) and that clumps must be formed deep in the wind. We derived a bolometric luminosity of 1.5 x 10...

  6. Constraining the Properties of the Eta Carinae System via 3-D SPH Models of Space-Based Observations: The Absolute Orientation of the Binary Orbit

    Science.gov (United States)

    Madura, Thomas I.; Gull, Theodore R.; Owocki, Stanley P.; Okazaki, Atsuo T.; Russell, Christopher M. P.

    2011-01-01

    The extremely massive (> 90 Stellar Mass) and luminous (= 5 x 10(exp 6) Stellar Luminosity) star Eta Carinae, with its spectacular bipolar "Homunculus" nebula, comprises one of the most remarkable and intensely observed stellar systems in the Galaxy. However, many of its underlying physical parameters remain unknown. Multiwavelength variations observed to occur every 5.54 years are interpreted as being due to the collision of a massive wind from the primary star with the fast, less dense wind of a hot companion star in a highly elliptical (e approx. 0.9) orbit. Using three-dimensional (3-D) Smoothed Particle Hydrodynamics (SPH) simulations of the binary wind-wind collision, together with radiative transfer codes, we compute synthetic spectral images of [Fe III] emission line structures and compare them to existing Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) observations. We are thus able, for the first time, to tightly constrain the absolute orientation of the binary orbit on the sky. An orbit with an inclination of approx. 40deg, an argument of periapsis omega approx. 255deg, and a projected orbital axis with a position angle of approx. 312deg east of north provides the best fit to the observations, implying that the orbital axis is closely aligned in 3-D space with the Homunculus symmetry axis, and that the companion star orbits clockwise on the sky relative to the primary.

  7. A Model for the 19th Century Eruption of Eta Carinae: CSM Interaction Like a Scaled-Down Type IIn Supernova

    CERN Document Server

    Smith, Nathan

    2012-01-01

    This paper proposes a simple model for the 19th century eruption of Eta Carinae that consists of two components: (1) a strong wind (MdotM=0.33 Msun/yr; v=200 km/s), blowing for 30 years, followed by (2) a 1e50 erg explosion in 1844. The ensuing collision between the fast ejecta and the CSM causes an increase in brightness observed at the end of 1844, followed by a sustained high-luminosity phase lasting for 10-15 years that matches the historical light curve. The emergent luminosity is powered by CSM interaction, analogous to the process in luminous Type IIn supernovae, except with 10 times lower explosion energy and at slower speeds (causing a longer duration and lower emergent luminosity). Such an explosive event provides a natural explanation for the light curve evolution, but also accounts for a number of puzzling attributes of the Homunculus nebula: (1) rough equipartition of total radiated and kinetic energy, (2) the double-shell structure of the Homunculus, (3) the apparent single age and Hubble-like f...

  8. The ``Ghost Shell'': Discovery of the Forward Shock from Colliding Winds about Eta Carinae

    Science.gov (United States)

    Dorland, B. N.; Currie, D. G.; Kaufer, A.; Bacciotti, F.

    2003-01-01

    We report on the newly discovered ``Ghost Shell'' around eta Carinae. We have detected a high-velocity ( ~ - 850 km /s), spatially extended, narrow emission feature lying in front of the southeast lobe of eta Carinae's homunculus. This feature has the speed of a high-velocity shock but the spectrum of a low-velocity shock. We propose that the Ghost Shell is the forward shock between the fast stellar wind of the great eruption of 1842 and the older, slow, massive wind. This discovery is described in more detail in Currie, Dorland, & Kaufer (2002).

  9. A Study of the Warm Ionized Medium Throughout the Sagittarius-Carina Arm

    CERN Document Server

    Krishnarao, Dhanesh; Benjamin, Robert A

    2016-01-01

    We present velocity-channel maps and analysis of the warm ionized medium (WIM) throughout the Sagittarius- Carina arm at Galactic longitudes 20 1000 pc along the far Carina arm. Physical conditions of the ionized gas are analyzed using the [S II]/H-alpha line ratio, which more closely traces H-alpha intensity than height above the plane, z, suggesting a stronger relationship with the in-situ electron density. We interpret this result as further evidence for the majority of the observed diffuse emission originating from in-situ ionized gas as opposed to scattered light from classical H II regions in the plane.

  10. An Aboriginal Australian Record of the Great Eruption of Eta Carinae

    CERN Document Server

    Hamacher, Duane W

    2010-01-01

    We present evidence that the Boorong Aboriginal people of northwestern Victoria observed the Great Eruption of Eta ({\\eta}) Carinae in the nineteenth century and incorporated the event into their oral traditions. We identify this star, as well as others not specifically identified by name, using descriptive material presented in the 1858 paper by William Edward Stanbridge in conjunction with early southern star catalogues. This identification of a transient astronomical event supports the assertion that Aboriginal oral traditions are dynamic and evolving, and not static. This is the only definitive indigenous record of {\\eta} Carinae's outburst identified in the literature to date.

  11. A Detailed Study of the Structure of the Nested Planetary Nebula, Hb 12, the Matryoshka Nebula

    Science.gov (United States)

    Clark, D. M.; López, J. A.; Edwards, M. L.; Winge, C.

    2014-11-01

    We present near-IR, integral field spectroscopic observations of the planetary nebula (PN) Hb 12 using Near-infrared Integral Field Spectrograph (NIFS) on Gemini-North. Combining NIFS with the adaptive optics system Altair, we provide a detailed study of the core and inner structure of this PN. We focus the analysis in the prominent emission lines [Fe II] (1.6436 μm), He I (2.0585 μm), H2 (2.1214 μm), and Brγ (2.16553 μm). We find that the [Fe II] emission traces a tilted system of bipolar lobes, with the northern lobe being redshifted and the southern lobe blueshifted. The [Fe II] emission is very faint at the core and only present close to the systemic velocity. There is no H2 emission in the core, whereas the core is prominent in the He I and Brγ recombination lines. The H2 emission is concentrated in equatorial arcs of emission surrounding the core and expanding at ~30 km s-1. These arcs are compared with Hubble Space Telescope images and shown to represent nested loops belonging to the inner sections of a much larger bipolar structure that replicates the inner one. The He I and Brγ emission from the core clearly show a cylindrical central cavity that seems to represent the inner walls of an equatorial density enhancement or torus. The torus is 0.''2 wide (≡200 AU radius at a distance of 2000 pc) and expanding at <=30 km s-1. The eastern wall of the inner torus is consistently more intense than the western wall, which could indicate the presence of an off-center star, such as is observed in the similar hourglass PN, MyCn 18. A bipolar outflow is also detected in Brγ emerging within 0.''1 from the core at ~ ± 40 km s-1.

  12. Central Stars of Planetary Nebulae

    CERN Document Server

    Jones, David

    2016-01-01

    In this brief invited review, I will attempt to summarise some of the key areas of interest in the study of central stars of planetary nebulae which (probably) won't be covered by other speakers' proceedings. The main focus will, inevitably, be on the subject of multiplicity, with special emphasis on recent results regarding triple central star systems as well as wide binaries which avoid a common-envelope phase. Furthermore, in light of the upcoming release of Kepler's Campaign 11 data, I will discuss a few of the prospects from that data including the unique possibility to detect merger products.

  13. Where Do Messy Planetary Nebulae Come From?

    Science.gov (United States)

    Kohler, Susanna

    2017-03-01

    If you examined images of planetary nebulae, you would find that many of them have an appearance that is too messy to be accounted for in the standard model of how planetary nebulae form. So what causes these structures?Examples of planetary nebulae that have a low probability of having beenshaped by a triple stellar system. They are mostly symmetric, with only slight departures (labeled) that can be explained by instabilities, interactions with the interstellar medium, etc. [Bear and Soker 2017]A Range of LooksAt the end of a stars lifetime, in the red-giant phase, strong stellar winds can expel the outer layers of the star. The hot, luminous core then radiates in ultraviolet, ionizing the gas of the ejected stellar layers and causing them to shine as a brightly colored planetary nebula for a few tens of thousands of years.Planetary nebulae come in a wide variety of morphologies. Some are approximately spherical, but others can be elliptical, bipolar, quadrupolar, or even more complex.Its been suggested that non-spherical planetary nebulae might be shaped by the presence of a second star in a binary system with the source of the nebula but even this scenario should still produce a structure with axial or mirror symmetry.A pair of scientists from Technion Israel Institute of Technology, Ealeal Bear and Noam Soker, argue that planetary nebulae with especially messy morphologies those without clear axial or point symmetries may have been shaped by an interacting triple stellar system instead.Examples of planetary nebulae that might have been shaped by a triple stellar system. They have some deviations from symmetry but also show signs of interacting with the interstellar medium. [Bear and Soker 2017]Departures from SymmetryTo examine this possibility more closely, Bear and Soker look at a sample of thousands planetary nebulae and qualitatively classify each of them into one of four categories, based on the degree to which they show signs of having been shaped by a

  14. High-resolution CO observation of the carbon star CIT 6 revealing the spiral structure and a nascent bipolar outflow

    CERN Document Server

    Kim, Hyosun; Hirano, Naomi; Zhao-Geisler, Ronny; Trejo, Alfonso; Yen, Hsi-Wei; Taam, Ronald E; Kemper, Francisca; Kim, Jongsoo; Byun, Do-Young; Liu, Tie

    2015-01-01

    CIT 6 is a carbon star in the transitional phase from the asymptotic giant branch (AGB) to the protoplanetary nebulae (pPN). Observational evidences of two point sources in the optical, circumstellar arc segments in an HC$_3$N line emission, and a bipolar nebula in near-infrared provide strong support for the presence of a binary companion. Hence, CIT 6 is very attractive for studying the role of companions in the AGB-pPN transition. We have carried out high resolution $^{12}$CO $J=2-1$ and $^{13}$CO $J=2-1$ observations of CIT 6 with the Submillimeter Array combined with the Submillimeter Telescope (single-dish) data. The $^{12}$CO channel maps reveal a spiral-shell pattern connecting the HC$_3$N segments in a continuous form, and an asymmetric outflow corresponding to the near-infrared bipolar nebula. Rotation of the $^{12}$CO channel peak position may be related to the inner spiral winding and/or the bipolar outflow. An eccentric orbit binary is suggested for the presences of an anisotropic mass loss to th...

  15. Polarization in Pulsar Wind Nebulae

    CERN Document Server

    Volpi, D; Amato, E; Bucciantini, N

    2009-01-01

    The main goal of our present work is to provide, for the first time, a simple computational tool that can be used to compute the brightness, the spectral index, the polarization, the time variability and the spectrum of the non-thermal light (both synchrotron and inverse Compton, IC) associated with the plasma dynamics resulting from given relativistic magnetohydrodynamics (RMHD) simulations. The proposed method is quite general, and can be applied to any scheme for RMHD and to all non-thermal emitting sources, e.g. pulsar wind nebulae (PWNe), and in particular to the Crab Nebula (CN) as in the present proceeding. Here only the linear optical and X-ray polarization that characterizes the PWNe synchrotron emission is analyzed in order to infer information on the inner bulk flow structure, to provide a direct investigation of the magnetic field configuration, in particular the presence and the strength of a poloidal component, and to understand the origin of some emitting features, such as the knot, whose origi...

  16. Radio Properties of Pinwheel Nebulae

    CERN Document Server

    Monnier, J D; Tuthill, P G; Danchi, W C

    2002-01-01

    A small number of dusty Wolf-Rayet stars have been resolved into pinwheel nebulae, defined by their ``rotating'' spiral dust shells observed in the infrared. This morphology is naturally explained by dust formation associated with colliding winds in a binary system. In order to confirm and further explore this hypothesis, we have observed the known pinwheel nebulae (WR 104 and WR 98a) as well as the suspected binary WR 112 at multiple radio wavelengths with the Very Large Array to search for non-thermal radio emission from colliding winds. The spectrum of each target is nearly flat between 5 and 22 GHz, consistent with the presence of non-thermal emission that is reduced at low frequencies by free-free absorption. This emission must lie outside the radio ``photosphere,'' leading us to estimate a lower limit to the physical size of the non-thermal emitting region that is larger than expected from current theory. Based on a radio and infrared comparison to WR 104 and 98a, we conclude that WR 112 is a likely can...

  17. NIF Discovery Science Eagle Nebula

    Science.gov (United States)

    Kane, Jave; Martinez, David; Pound, Marc; Heeter, Robert; Huntington, Channing; Casner, Alexis; Villette, Bruno; Mancini, Roberto

    2016-10-01

    For almost 20 years a team of astronomers, theorists and experimentalists have investigated the creation of the famous Pillars of the Eagle Nebula and similar parsec-scale structures at the boundaries of HII regions in molecular hydrogen clouds, using a combination of astronomical observations, astrophysical simulations, and recently, scaled laboratory experiments. Eagle Nebula, one of the National Ignition Facility (NIF) Discovery Science programs, has completed four NIF shots to study the dense `shadowing' model of pillar formation, and been awarded more shots to study the `cometary' model. These experiments require a long-duration drive, 30 ns or longer, to generate deeply nonlinear ablative hydrodynamics. A novel x-ray source featuring multiple UV-driven hohlraums driven is used. The source directionally illuminates a science package, mimicking a cluster of stars. The first four NIF shots generated radiographs of shadowing-model pillars, and suggested that cometary structures can be generated. The velocity and column density profiles of the NIF shadowing and cometary pillars have been compared with observations of the Eagle Pillars made at millimeter observatories, and indicate cometary growth is key to matching observations. Supported in part by a Grant from the DOE OFES HEDLP program. Prepared by LLNL under Contract DE-AC52-07NA27344.

  18. Eta Carinae and the Homunculus: an Astrophysical Laboratory

    Science.gov (United States)

    Gull, T. R.

    2007-08-01

    High spatial resolution spectroscopy with HST/STIS between 1998.0 and 2004.2 has provided much exciting information about the central binary system and the physics of its N-rich, C,O-poor ejecta. Stellar He I profiles, noticeably blue-shifted relative to P Cygni H and Fe II line profiles, originate from the ionized wind region between two massive companions. Changes in profiles of He I singlet and triplet lines provide clues to the excitation mechanisms involved as the hot, UV companion moves in its highly eccentric orbit. For 90% of the 5.54-year period, the spectra of nearby Weigelt blobs and the Little Homunculus include highly excited emission lines of Ar, Ne, and Fe. During the few month-long spectroscopic minimum, these systems are deprived of Lyman continuum. Recombination, plus cooling, occurs. In the skirt region between the bipolar Homunculus, a neutral emission region, devoid of hydrogen emission, glows in Ti II, Fe I, Sr II, Sc II, etc. We find the ejecta to have Ti/Ni abundances nearly 100 times solar, not due to nuclear processing, but due to lack of oxygen. Many metals normally tied up in interstellar dust remain in gaseous phase. Much information is being obtained on the physical processes in these warm N-rich gases, whose excitation varies with time in a predictable pattern. Indeed recent GRB high dispersion spectra include signatures of circumGRB warm gases. This indicates that the early, primordial massive stars have warm massive ejecta reminiscent to that around Eta Carinae.

  19. PTF10nvg: An Outbursting Class I Protostar in the Pelican/North American Nebula

    CERN Document Server

    Covey, Kevin R; Miller, Adam A; Poznanski, Dovi; Cenko, S Bradley; Silverman, Jeffrey M; Bloom, Joshua S; Kasliwal, Mansi M; Fischer, William; Rayner, John; Rebull, Luisa M; Butler, Nathaniel R; Filippenko, Alexei V; Law, Nicholas M; Ofek, Eran O; Agueros, Marcel; Dekany, Richard G; Rahmer, Gustavo; Hale, David; Smith, Roger; Quimby, Robert M; Nugent, Peter; Jacobsen, Janet; Zolkower, Jeff; Velur, Viswa; Walters, Richard; Henning, John; Bui, Khanh; McKenna, Dan; Kulkarni, Shrinivas R; Klein, Christopher

    2010-01-01

    During a synoptic survey of the North American Nebula region, the Palomar Transient Factory (PTF) detected an optical outburst (dubbed PTF10nvg) associated with the previously unstudied flat or rising spectrum infrared source IRAS 20496+4354. The PTF R-band light curve reveals that PTF10nvg brightened by more than 5 mag during the current outburst, rising to a peak magnitude of R~13.5 in 2010 Sep. Follow-up observations indicate PTF10nvg has undergone a similar ~5 mag brightening in the K band, and possesses a rich emission-line spectrum, including numerous lines commonly assumed to trace mass accretion and outflows. Many of these lines are blueshifted by ~175 km/s from the North American Nebula's rest velocity, suggesting that PTF10nvg is driving an outflow. Optical spectra of PTF10nvg show several TiO/VO bandheads fully in emission, indicating the presence of an unusual amount of dense (> 10^10 cm^-3), warm (1500-4000 K) circumstellar material. Near-infrared spectra of PTF10nvg appear quite similar to a spe...

  20. Fast, low-ionization emission regions of the planetary nebula M2-42

    CERN Document Server

    Danehkar, A; Steffen, W

    2016-01-01

    Spatially resolved observations of the planetary nebula M2-42 (PN G008.2-04.8) obtained with the Wide Field Spectrograph on the Australian National University 2.3 m telescope have revealed the remarkable features of bipolar collimated jets emerging from its main structure. Velocity-resolved channel maps derived from the [N II] $\\lambda$6584 emission line disentangle different morphological components of the nebula. This information is used to develop a three-dimensional morpho-kinematic model, which consists of an equatorial dense torus and a pair of asymmetric bipolar outflows. The expansion velocity of about 20 km s$^{-1}$ is measured from the spectrum integrated over the main shell. However, the deprojected velocities of the jets are found to be in the range of 80-160 km s$^{-1}$ with respect to the nebular center. It is found that the mean density of the collimated outflows, 595 $\\pm$ 125 cm$^{-3}$, is five times lower than that of the main shell, 3150 cm$^{-3}$, whereas their singly ionized nitrogen and ...

  1. FAST, LOW-IONIZATION EMISSION REGIONS OF THE PLANETARY NEBULA M2-42

    Energy Technology Data Exchange (ETDEWEB)

    Danehkar, A.; Parker, Q. A. [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Steffen, W., E-mail: ashkbiz.danehkar@cfa.harvard.edu [Instituto de Astronomía, Universidad Nacional Autónoma de México, C.P.22860, Ensenada (Mexico)

    2016-02-15

    Spatially resolved observations of the planetary nebula M2-42 (PN G008.2−04.8) obtained with the Wide Field Spectrograph on the Australian National University 2.3 m telescope have revealed the remarkable features of bipolar collimated jets emerging from its main structure. Velocity-resolved channel maps derived from the [N ii] λ6584 emission line disentangle different morphological components of the nebula. This information is used to develop a three-dimensional morpho-kinematic model, which consists of an equatorial dense torus and a pair of asymmetric bipolar outflows. The expansion velocity of about 20 km s{sup −1} is measured from the spectrum integrated over the main shell. However, the deprojected velocities of the jets are found to be in the range of 80–160 km s{sup −1} with respect to the nebular center. It is found that the mean density of the collimated outflows, 595 ± 125 cm{sup −3}, is five times lower than that of the main shell, 3150 cm{sup −3}, whereas their singly ionized nitrogen and sulfur abundances are about three times higher than those determined from the dense shell. The results indicate that the features of the collimated jets are typical of fast, low-ionization emission regions.

  2. HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA (color)

    Science.gov (United States)

    2002-01-01

    A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This colorful photo shows a ground-based image of the entire Crab Nebula, the remnant of a supernova explosion witnessed over 900 years ago. The nebula, which is 10 light-years across, is located 7,000 light-years away in the constellation Taurus. The green, yellow and red filaments concentrated toward the edges of the nebula are remnants of the star that were ejected into space by the explosion. At the center of the Crab Nebula lies the Crab Pulsar -- the collapsed core of the exploded star. The Crab Pulsar is a rapidly rotating neutron star -- an object only about six miles across, but containing more mass than our Sun. As it rotates at a rate of 30 times per second the Crab Pulsar's powerful magnetic field sweeps around, accelerating particles, and whipping them out into the nebula at speeds close to that of light. The blue glow in the inner part of the nebula -- light emitted by energetic electrons as they spiral through the Crab's magnetic field -- is powered by the Crab Pulsar. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

  3. Processing NASA Earth Science Data on Nebula Cloud

    Science.gov (United States)

    Chen, Aijun; Pham, Long; Kempler, Steven

    2012-01-01

    Three applications were successfully migrated to Nebula, including S4PM, AIRS L1/L2 algorithms, and Giovanni MAPSS. Nebula has some advantages compared with local machines (e.g. performance, cost, scalability, bundling, etc.). Nebula still faces some challenges (e.g. stability, object storage, networking, etc.). Migrating applications to Nebula is feasible but time consuming. Lessons learned from our Nebula experience will benefit future Cloud Computing efforts at GES DISC.

  4. SWAS Observations of Water in Molecular Outflows

    CERN Document Server

    Franklin, J; Kaufman, M J; Melnick, G J; Neufeld, D A; Hollenbach, D J; Bergin, E A

    2007-01-01

    We present SWAS detections of the ground-state 1(10)-1(01) transition of o-H2O at 557 GHz in 18 molecular outflows. These results are combined with ground-based observations of the J=1-0 transitions of 12CO and 13CO obtained at the FCRAO and, for a subset of the outflows, data from ISO. Assuming the SWAS water line emission originates from the same gas traced by CO emission, we find that the outflowing gas in most outflows has an o-H2O abundance relative to H2 of between 10(-7) and 10(-6). Analysis of the water abundance as a function of outflow velocity reveals a strong dependence. The water abundance increases with velocity, and at the highest outflow velocities some outflows have relative o-H2O abundances of order 10(-4). However the mass of gas with such elevated water abundances represents less that 1% of the total outflow gas mass. The ISO LWS observations of high-J rotational lines of CO and the 179.5 micron transition of o-H2O provide evidence for a warmer outflow component than required to produce ei...

  5. Morphologies of protostellar outflows: An ALMA view

    CERN Document Server

    Peters, Thomas; Seifried, Daniel; Banerjee, Robi; Klessen, Ralf S

    2014-01-01

    The formation of stars is usually accompanied by the launching of protostellar outflows. Observations with the Atacama Large Millimetre/sub-millimetre Array (ALMA) will soon revolutionalise our understanding of the morphologies and kinematics of these objects. In this paper, we present synthetic ALMA observations of protostellar outflows based on numerical magnetohydrodynamic collapse simulations. We find significant velocity gradients in our outflow models and a very prominent helical structure within the outflows. We speculate that the disk wind found in the ALMA Science Verification Data of HD 163296 presents a first instance of such an observation.

  6. The COMPLETE Survey of Outflows in Perseus

    CERN Document Server

    Arce, Hector G; Goodman, Alyssa A; Pineda, Jaime E; Halle, Michael W; 10.1088/0004-637X/715/2/1170

    2010-01-01

    We present a study on the impact of molecular outflows in the Perseus molecular cloud complex using the COMPLETE survey large-scale 12CO(1-0) and 13CO(1-0) maps. We used three-dimensional isosurface models generated in RA-DEC-Velocity space to visualize the maps. This rendering of the molecular line data allowed for a rapid and efficient way to search for molecular outflows over a large (~ 16 sq. deg.) area. Our outflow-searching technique detected previously known molecular outflows as well as new candidate outflows. Most of these new outflow-related high-velocity features lie in regions that have been poorly studied before. These new outflow candidates more than double the amount of outflow mass, momentum, and kinetic energy in the Perseus cloud complex. Our results indicate that outflows have significant impact on the environment immediately surrounding localized regions of active star formation, but lack the energy needed to feed the observed turbulence in the entire Perseus complex. This implies that oth...

  7. Model comparison of the dark matter profiles of Fornax, Sculptor, Carina and Sextans

    NARCIS (Netherlands)

    Breddels, Maarten A.; Helmi, Amina

    2013-01-01

    Aims: We compare dark matter profile models of four dwarf spheroidal galaxies satellites of the Milky Way using Bayesian evidence. Methods: We use orbit based dynamical models to fit the 2nd and 4th moments of the line of sight velocity distributions of the Fornax, Sculptor, Carina and Sextans dwarf

  8. X-ray Gyrations of Eta Carinae, or, Is Presence of Evidence Evidence of Presence?

    CERN Document Server

    Corcoran, M F; Gull, T R; Damineli, A; Davidson, K

    2004-01-01

    We review the properties of the variable X-ray emission from the extremely massive star Eta Carinae concentrating on the last X-ray minimum, and briefly consider the possible role of a binary companion star on the observational properties of the system.

  9. The Magnetic Field Effect on Planetary Nebulae

    Institute of Scientific and Technical Information of China (English)

    A. R. Khesali; K. Kokabi

    2006-01-01

    In our previous work on the 3-dimensional dynamical structure of planetary nebulae the effect of magnetic field was not considered. Recently Jordan et al. have directly detected magnetic fields in the central stars of some planetary nebulae. This discovery supports the hypothesis that the non-spherical shape of most planetary nebulae is caused by magnetic fields in AGB stars. In this study we focus on the role of initially weak toroidal magnetic fields embedded in a stellar wind in altering the shape of the PN. We found that magnetic pressure is probably influential on the observed shape of most PNe.

  10. Interstellar gas in the Gum Nebula

    Science.gov (United States)

    Wallerstein, G.; Jenkins, E. B.; Silk, J.

    1980-01-01

    A survey of the interstellar gas near the Gum Nebula by optical observation of 67 stars at Ca II, 42 stars at Na I, and 14 stars in the UV with the Copernicus satellite provided radial velocities and column densities for all resolved absorption components. Velocity dispersions for gas in the Gum Nebula are not significantly larger than in the general interstellar medium; the ionization structure is predominantly that of an H II region with moderately high ionization. Denser, more highly ionized clouds are concentrated toward the Gum Nebula; these clouds do not show the anomalously high ionization observed in the Vela remnant clouds.

  11. From stellar nebula to planetesimals

    CERN Document Server

    Marboeuf, Ulysse; Alibert, Yann; Cabral, Nahuel; Benz, Willy

    2014-01-01

    Solar and extrasolar comets and extrasolar planets are the subject of numerous studies in order to determine their chemical composition and internal structure. In the case of planetesimals, their compositions are important as they govern in part the composition of future planets. The present works aims at determining the chemical composition of icy planetesimals, believed to be similar to present day comets, formed in stellar systems of solar chemical composition. The main objective of this work is to provide valuable theoretical data on chemical composition for models of planetesimals and comets, and models of planet formation and evolution. We have developed a model that calculates the composition of ices formed during the cooling of the stellar nebula. Coupled with a model of refractory element formation, it allows us to determine the chemical composition and mass ratio of ices to rocks in icy planetesimals throughout in the protoplanetary disc. We provide relationships for ice line positions (for differen...

  12. Temperature, salinity, nutrients, carbon, and other profile data collected worldwide as part of the CARINA project (NODC Accession 0057766)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The CARINA (CARbon dioxide IN the Atlantic Ocean) data synthesis project is an international collaborative effort of the EU IP CARBOOCEAN, and US partners. It has...

  13. Outflow - Core Interaction in Barnard 1

    CERN Document Server

    Hiramatsu, Masaaki; Takakuwa, Shigehisa

    2010-01-01

    In order to study how outflows from protostars influence the physical and chemical conditions of the parent molecular cloud, we have observed Barnard 1 (B1) main core, which harbors four Class 0 and three Class I sources, in the CO (J=1-0), CH3OH (J_K=2_K-1_K), and the SiO (J=1-0) lines using the NRO 45 m telescope. We have identified three CO outflows in this region; one is an elongated (~ 0.3 pc) bipolar outflow from a Class 0 protostar B1-c in the submillimeter clump SMM 2, another is a rather compact (~ 0.1 pc) outflow from a Class I protostar B1 IRS in the clump SMM 6, and the other is extended outflow from a Class I protostar in SMM 11. In the western lobe of the SMM 2 outflow, both the SiO and CH3OH lines show broad redshifted wings with the terminal velocities of 25 km/s and 13 km/s, respectively. It is likely that the shocks caused by the interaction between the outflow and ambient gas enhance the abundance of SiO and CH3OH in the gas phase. The total energy input rate by the outflows (1.1x10^{-3} Ls...

  14. Observations of planetary nebulae in the Galactic Bulge

    CERN Document Server

    Cuisinier, F; Köppen, J; Acker, A; Stenholm, B

    2000-01-01

    High quality spectrophotometric observations of 30 Planetary Nebulae in the Galactic Bulge have been made. Accurate reddenings, plasma parameters, and abundances of He,O,N,S,Ar,Cl are derived. We find the abundances of O,S,Ar in the Planetary Nebulae in the Galactic Bulge to be comparable with the abundances of the Planetary Nebulae in the Disk, high abundances being maybe slightly more frequent in the Bulge. The distribution of the N/O ratio does not present in the Galactic Bulge Planetary Nebulae the extension to high values that it presents in the Disk Planetary Nebulae. We interpret this as a signature of the greater age of Bulge Planetary Nebulae. We thus find the Bulge Planetary Nebulae to be an old population, slightly more metal-rich than the Disk Planetary Nebulae. The population of the Bulge Planetary Nebulae shows hence the same characteristics than the Bulge stellar population.

  15. A 3D view of the outflow in the Orion Molecular Cloud 1 (OMC-1)

    CERN Document Server

    Nissen, H D; Gustafsson, M; Bally, J; Lemaire, J -L; Favre, C; Field, D

    2012-01-01

    The fast outflow emerging from a region associated with massive star formation in the Orion Molecular Cloud 1 (OMC-1), located behind the Orion Nebula, appears to have been set in motion by an explosive event. Here we study the structure and dynamics of outflows in OMC-1. We combine radial velocity and proper motion data for near-IR emission of molecular hydrogen to obtain the first 3-dimensional (3D) structure of the OMC-1 outflow. Our work illustrates a new diagnostic tool for studies of star formation that will be exploited in the near future with the advent of high spatial resolution spectro-imaging in particular with data from the Atacama Large Millimeter Array (ALMA). We use published radial and proper motion velocities obtained from the shock-excited vibrational emission in the H2 v=1-0 S(1) line at 2.122 $\\mu$m obtained with the GriF instrument on the Canada-France-Hawaii Telescope, the Apache Point Observatory, the Anglo-Australian Observatory and the Subaru Telescope. These data give the 3D velocity...

  16. The three dimensional dynamic structure of the inner Orion Nebula

    CERN Document Server

    O'Dell, C R; Abel, N P; Ferland, G J; Arthur, S J

    2008-01-01

    The three dimensional structure of the brightest part of the Orion Nebula is assessed in the light of published and new data. We find that the widely accepted model of a concave blister of ionized material needs to be altered in the southwest direction from the Trapezium, where we find that the Orion-S feature is a separate cloud of very optically thick molecules within the body of ionized gas, which is probably the location of the multiple embedded sources that produce the outflows that define the Orion-S star formation region. Evidence for this cloud comes from the presence of H2CO lines in absorption in the radio continuum and discrepancies in the extinction derived from radio-optical and optical only emission. We present an equilibrium Cloudy model of the Orion-S cloud, which successfully reproduces many observed properties of this feature. We also report the discovery of an open-sided shell of [O III] surrounding the Trapezium stars, revealed through emission line ratio images and the onset of radiation ...

  17. NUCLEOSYNTHESIS AND THE INHOMOGENEOUS CHEMICAL EVOLUTION OF THE CARINA DWARF GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Venn, Kim A.; Divell, Mike [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 1A1 (Canada); Shetrone, Matthew D. [McDonald Observatory, University of Texas at Austin, HC75 Box 1337-McD, Fort Davis, TX 79734 (United States); Irwin, Mike J. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB03 0HA (United Kingdom); Hill, Vanessa [Laboratoire Cassiopee UMR 6202, Universite de Nice Sophia-Antipolis, CNRS, Observatoire de la Cote d' Azur (France); Jablonka, Pascale [GEPI, Observatoire de Paris, CNRS UMR 8111, Universite Paris Diderot, F-92125, Meudon, Cedex (France); Tolstoy, Eline; Lemasle, Bertrand; Starkenburg, Else; Helmi, Amina [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Letarte, Bruno [South African Astronomical Observatory, Observatory Road, 7935 Observatory (South Africa); Baldner, Charles [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Battaglia, Giuseppina; Primas, Francesca [European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching (Germany); Kaufer, Andreas, E-mail: kvenn@uvic.ca [European Southern Observatory, Alonso de Cordova 3107, Santiago (Chile)

    2012-06-01

    The detailed abundances of 23 chemical elements in nine bright red giant branch stars in the Carina dwarf spheroidal galaxy are presented based on high-resolution spectra gathered at the Very Large Telescope (VLT) and Magellan telescopes. A spherical model atmospheres analysis is applied using standard methods (local thermodynamic equilibrium and plane-parallel radiative transfer) to spectra ranging from 380 to 680 nm. Stellar parameters are found to be consistent between photometric and spectroscopic analyses, both at moderate and high resolution. The stars in this analysis range in metallicity from -2.9 < [Fe/H] <-1.3, and adopting the ages determined by Lemasle et al., we are able to examine the chemical evolution of Carina's old and intermediate-aged populations. One of the main results from this work is the evidence for inhomogeneous mixing in Carina and therefore for a poor statistical sampling of the supernova contributions when forming stars; a large dispersion in [Mg/Fe] indicates poor mixing in the old population, an offset in the [{alpha}/Fe] ratios between the old and intermediate-aged populations (when examined with previously published results) suggests that the second star formation event occurred in {alpha}-enriched gas, and one star, Car-612, seems to have formed in a pocket enhanced in SN Ia/II products. This latter star provides the first direct link between the formation of stars with enhanced SN Ia/II ratios in dwarf galaxies to those found in the outer Galactic halo (Ivans et al.). Another important result is the potential evidence for SN II driven winds. We show that the very metal-poor stars in Carina have not been enhanced in asymptotic giant branch or SN Ia products, and therefore their very low ratios of [Sr/Ba] suggests the loss of contributions from the early SNe II. Low ratios of [Na/Fe], [Mn/Fe], and [Cr/Fe] in two of these stars support this scenario, with additional evidence from the low [Zn/Fe] upper limit for one star. It is

  18. Using kinematic properties of pre-planetary nebulae to constrain engine paradigms

    Science.gov (United States)

    Blackman, Eric G.; Lucchini, Scott

    2014-05-01

    Some combination of binary interactions and accretion plausibly conspire to produce the ubiquitous collimated outflows from planetary nebulae (PN) and their presumed pre-PN (PPN) precursors. But which accretion engines are viable? The difficulty in observationally resolving the engines warrants the pursuit of indirect constraints. We show how kinematic outflow data for 19 PPN can be used to determine the minimum required accretion rates. We consider main-sequence (MS) and white dwarf (WD) accretors and five example accretion rates inferred from published models to compare with the minima derived from outflow momentum conservation. While our primary goal is to show the method in anticipation of more data and better theoretical constraints, taking the present results at face value already rules out modes of accretion: Bondi-Hoyle-Lyttleton (BHL) wind accretion and wind Roche lobe overflow (M-WRLOF, based on Mira parameters) are too feeble for all 19/19 objects for an MS accretor. For a WD accretor, BHL is ruled out for 18/19 objects and M-WRLOF for 15/19 objects. RLOF from the primary at the Red Rectangle level can accommodate 7/19 objects, though RLOF modes with higher accretion rates are not yet ruled out. Accretion modes operating from within common envelope evolution can accommodate all 19 objects, if jet collimation can be maintained. Overall, sub-Eddington rates for an MS accretor are acceptable but 8/19 would require super-Eddington rates for a WD. L61

  19. A detailed study of the structure of the nested planetary nebula, Hb 12, the Matryoshka nebula

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D. M.; López, J. A. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Campus Ensenada, Ensenada, Baja California, 22860 (Mexico); Edwards, M. L. [LBT Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Winge, C., E-mail: dmclark@astrosen.unam.mx, E-mail: jal@astrosen.unam.mx, E-mail: medwards@lbto.org, E-mail: cwinge@gemini.edu [Gemini Observatory, Southern Operations Center, c/o AURA Inc., Casilla 603, La Serena (Chile)

    2014-11-01

    We present near-IR, integral field spectroscopic observations of the planetary nebula (PN) Hb 12 using Near-infrared Integral Field Spectrograph (NIFS) on Gemini-North. Combining NIFS with the adaptive optics system Altair, we provide a detailed study of the core and inner structure of this PN. We focus the analysis in the prominent emission lines [Fe II] (1.6436 μm), He I (2.0585 μm), H{sub 2} (2.1214 μm), and Br{sub γ} (2.16553 μm). We find that the [Fe II] emission traces a tilted system of bipolar lobes, with the northern lobe being redshifted and the southern lobe blueshifted. The [Fe II] emission is very faint at the core and only present close to the systemic velocity. There is no H{sub 2} emission in the core, whereas the core is prominent in the He I and Br{sub γ} recombination lines. The H{sub 2} emission is concentrated in equatorial arcs of emission surrounding the core and expanding at ∼30 km s{sup –1}. These arcs are compared with Hubble Space Telescope images and shown to represent nested loops belonging to the inner sections of a much larger bipolar structure that replicates the inner one. The He I and Br{sub γ} emission from the core clearly show a cylindrical central cavity that seems to represent the inner walls of an equatorial density enhancement or torus. The torus is 0.''2 wide (≡200 AU radius at a distance of 2000 pc) and expanding at ≤30 km s{sup –1}. The eastern wall of the inner torus is consistently more intense than the western wall, which could indicate the presence of an off-center star, such as is observed in the similar hourglass PN, MyCn 18. A bipolar outflow is also detected in Br{sub γ} emerging within 0.''1 from the core at ∼ ± 40 km s{sup –1}.

  20. Geminga's puzzling pulsar wind nebula

    CERN Document Server

    Posselt, B; Slane, P O; Romani, R; Bucciantini, N; Bykov, A M; Kargaltsev, O; Weisskopf, M C; Ng, C -Y

    2016-01-01

    We report on six new Chandra observations of the Geminga pulsar wind nebula (PWN). The PWN consists of three distinct elongated structures - two $\\approx 0.2 d_{250}$ pc long lateral tails and a segmented axial tail of $\\approx 0.05 d_{250}$ pc length, where $d_{250}=d/(250 {\\rm pc})$. The photon indices of the power law spectra of the lateral tails, $\\Gamma \\approx 1$, are significantly harder than those of the pulsar ($\\Gamma \\approx 1.5$) and the axial tail ($\\Gamma \\approx 1.6$). There is no significant diffuse X-ray emission between the lateral tails -- the ratio of the X-ray surface brightness between the south tail and this sky area is at least 12. The lateral tails apparently connect directly to the pulsar and show indication of moving footpoints. The axial tail comprises time-variable emission blobs. However, there is no evidence for constant or decelerated outward motion of these blobs. Different physical models are consistent with the observed morphology and spectra of the Geminga PWN. In one scena...

  1. The Crab Nebula flaring activity

    Directory of Open Access Journals (Sweden)

    G. Montani

    2014-12-01

    Full Text Available The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼1015 cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼109, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  2. The Crab Nebula flaring activity

    Energy Technology Data Exchange (ETDEWEB)

    Montani, G., E-mail: giovanni.montani@frascati.enea.it [ENEA – C.R, UTFUS-MAG, via Enrico Fermi 45, I-00044 Frascati (RM) (Italy); Dipartimento di Fisica, Università di Roma “Sapienza”, p.le Aldo Moro 5, I-00185 Roma (Italy); Bernardini, M.G. [INAF – Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy)

    2014-12-12

    The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼10{sup 15} cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼10{sup 9}, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  3. Investigating Cepheid $\\ell$ Carinae's Cycle-to-cycle Variations via Contemporaneous Velocimetry and Interferometry

    CERN Document Server

    Anderson, R I; Kervella, P; Breitfelder, J; LeBouquin, J -B; Eyer, L; Gallenne, A; Palaversa, L; Semaan, T; Saesen, S; Mowlavi, N

    2015-01-01

    Baade-Wesselink-type (BW) techniques enable geometric distance measurements of Cepheid variable stars in the Galaxy and the Magellanic clouds. The leading uncertainties involved concern projection factors required to translate observed radial velocities (RVs) to pulsational velocities and recently discovered modulated variability. We carried out an unprecedented observational campaign involving long-baseline interferometry (VLTI/PIONIER) and spectroscopy (Euler/Coralie) to search for modulated variability in the long-period (P $\\sim$ 35.5 d) Cepheid Carinae. We determine highly precise angular diameters from squared visibilities and investigate possible differences between two consecutive maximal diameters, $\\Delta_{\\rm{max}} \\Theta$. We characterize the modulated variability along the line-of-sight using 360 high-precision RVs. Here we report tentative evidence for modulated angular variability and confirm cycle-to-cycle differences of $\\ell$ Carinae's RV variability. Two successive maxima yield $\\Delta_{\\rm...

  4. The Abundance of Iron-Peak Elements and the Dust Composition in eta Carinae: Manganese

    Science.gov (United States)

    Bautista, M. A.; Melendez, M.; Hartman, H.; Gull, T. R.; Lodders, K.

    2010-01-01

    We study the chemical abundances of the Strontium Filament found in the ejecta of (eta) Carinae. In particular, we derive the abundances of iron-peak elements front spectra of their singly ionized ions present in the optical/IR spectra. In this paper we analyze the spectrum of Mn II using a new non-LTE model for this system. In constructing this models we carried out theoretical calculations of radiative transition rates and electron impact excitation rate coefficients. We find that relative to Ni the gas phase abundance ratio of Mn is roughly solar, similar to the Cr abundance but in contrast to the large enhancements in the abundances of Sc and Ti. NVe interpret this result as an indication of non-equilibrium condensation in the ejecta of (eta) Carinae.

  5. Hydroxyl Emission in the Westbrook Nebula

    Science.gov (United States)

    Strack, Angelica; Araya, Esteban; Ghosh, Tapasi; Arce, Hector G.; Lebron, Mayra E.; Salter, Christopher J.; Minchin, Robert F.; Pihlstrom, Ylva; Kurtz, Stan; Hofner, Peter; Olmi, Luca

    2016-06-01

    CRL 618, also known as the Westbrook Nebula, is a carbon-rich pre-planetary nebula. Hydroxyl (OH) transitions are typically not detected in carbon-rich late-type stellar objects, however observations conducted with the 305m Arecibo Telescope in 2008 resulted in the detection of 4765 MHz OH emission in CRL 618. We present results of observations carried out a few months after the original detection that confirm the line. This is the first detection of 4765 MHz OH emission (most likely a maser) in a pre-planetary nebula. Follow up observations conducted in 2015 resulted in non-detection of the 4765 MHz OH transition. This behavior is consistent with the high level of variability of excited OH lines that have been detected toward a handful of other pre-planetary nebulae. Our work supports that excited OH masers are short-lived during the pre-planetary nebula phase. We also conducted a search for other OH transitions from 1612 MHz to 8611 MHz with the Arecibo Telescope; we report no other detections at rms levels of ~5 mJy.This work has made use of the computational facilities donated by Frank Rodeffer to the WIU Astrophysics Research Laboratory. We also acknowledge support from M. & C. Wong RISE scholarships and a grant from the WIU College of Arts and Sciences.

  6. On the He burning phases of the Carina dSph

    CERN Document Server

    Fabrizio, M; Bono, G; Stetson, P B; Walker, A R; Buonanno, R; Cassisi, S; Ferraro, I; Iannicola, G; Monelli, M; Nonino, M; Pulone, L; Thevénin, F

    2013-01-01

    We performed a detailed comparison between predicted He burning phases and multiband photometry of the Carina dwarf spheroidal galaxy. We found a good agreement with the predictions computed assuming an {\\alpha}-enhanced chemical mixture, indicating a mean metallicity [Fe/H] ~ -1.8 with a raw observed peak-to-peak spread in iron abundance of 0.4\\pm0.2 dex.

  7. A Comprehensive, Wide-Field Study of Pulsating Stars in the Carina Dwarf Spheroidal Galaxy

    OpenAIRE

    Vivas, A. Katherina; Mateo, Mario

    2013-01-01

    We report the detection of 388 pulsating variable stars (and some additional miscellaneous variables) in the Carina dSph galaxy over an area covering the full visible extent of the galaxy and extending a few times beyond its photometric (King) tidal radius along the direction of its major axis. Included in this total are 340 newly discovered dwarf Cepheids which are mostly located ~2.5 magnitudes below the horizontal branch and have very short periods (

  8. Radio jets and outflows of cold gas

    CERN Document Server

    Morganti, Raffaella

    2011-01-01

    Massive gas outflows are considered a key component in the process of galaxy formation and evolution. It is, therefore, not surprising that a lot of effort is going in quantifying their impact via detailed observations. This short contribution presents recent results obtained from HI and CO observations of different objects where the AGN - and in particular the radio jet - is likely playing an important role in producing the gas outflows. These preliminary results are reinforcing the conclusion that these outflows have a complex and multiphase structure where cold gas in different phases (atomic and molecular) is involved and likely represent a major component. These results will also provide important constraints for establishing how the interaction between AGN/radio jet and the surrounding ISM occurs and how efficiently the gas should cool to produce the observed properties of the outflowing gas. HI likely represents an intermediate phase in this process, while the molecular gas would be the final stage. Wh...

  9. Accretion and Outflow Activity in Brown Dwarfs

    CERN Document Server

    Riaz, B

    2013-01-01

    An investigation of the magnetospheric accretion and outflow signatures in sub-stellar objects is a natural extension of similar studies conducted on classical T Tauri stars (CTTS), and helps understand if brown dwarfs (BDs) follow the same formation mechanism as stars. Over the past decade, evidence for accretion in very low-mass stars (VLMs) and BDs has been accumulated using various techniques, which indicates that the overall accretion characteristics are continuous across the sub-stellar boundary. Outflow activity in VLMs and BDs has been confirmed based on spectro-astrometry of forbidden emission lines observed in the optical, and in millimetre continuum images of CO J=2-1 emission. This review summarizes the past and current state of observational work on accretion and outflow activity in VLMs and BDs, particularly with the advent of new instruments such as VLT/X-Shooter which has allowed the study of several accretion and outflow indicators over a wider wavelength range.

  10. Electron-positron outflow from black holes

    CERN Document Server

    Van Putten, M H P M

    2000-01-01

    Gamma-ray bursts (GRBs) appear as the brightest transient phenomena in the Universe. The nature of the central engine in GRBs is a missing link in the theory of fireballs to their stellar mass progenitors. Here it is shown that rotating black holes produce electron-positron outflow when brought into contact with a strong magnetic field. The outflow is produced by a coupling of the spin of the black hole to the orbit of the particles. For a nearly extreme Kerr black hole, particle outflow from an initial state of electrostatic equilibrium has a normalized isotropic emission of $\\sim external magnetic field strength, B_c=4.4 x 10^{13}G, and M is the mass of the black hole. This initial outflow has a half-opening angle given.

  11. Disks, accretion and outflows of brown dwarfs

    CERN Document Server

    Joergens, V; Liu, Y; Pascucci, I; Whelan, E; Alcala, J; Biazzo, K; Costigan, G; Gully-Santiago, M; Henning, Th; Natta, A; Rigliaco, E; Rodriguez-Ledesma, V; Sicilia-Aguilar, A; Tottle, J; Wolf, S

    2012-01-01

    Characterization of the properties of young brown dwarfs are important to constraining the formation of objects at the extreme low-mass end of the IMF. While young brown dwarfs share many properties with solar-mass T Tauri stars, differences may be used as tests of how the physics of accretion/outflow and disk chemistry/dissipation depend on the mass of the central object. This article summarizes the presentations and discussions during the splinter session on 'Disks, accretion and outflows of brown dwarfs' held at the CoolStars17 conference in Barcelona in June 2012. Recent results in the field of brown dwarf disks and outflows include the determination of brown dwarf disk masses and geometries based on Herschel far-IR photometry (70-160 um), accretion properties based on X-Shooter spectra, and new outflow detections in the very low-mass regime.

  12. Carina® and Esteem®: a systematic review of fully implantable hearing devices.

    Directory of Open Access Journals (Sweden)

    Janaina Oliveira Bentivi Pulcherio

    Full Text Available To review the outcomes of the fully implantable middle ear devices Carina and Esteem regarding the treatment of hearing loss.PubMed, Embase, Scielo, and Cochrane Library databases were searched.Abstracts of 77 citations were screened, and 43 articles were selected for full review. From those, 22 studies and two literature reviews in English directly demonstrating the results of Carina and Esteem were included.There were a total of 244 patients ranging from 18 to 88 years. One hundred and 10 patients were implanted with Carina and with 134 Esteem. There were registered 92 males and 67 females. Five studies provided no information about patients' age or gender. From the data available, the follow-up ranged from 2 to 29.4 months.The comparison of the results about word recognition is difficult as there was no standardization of measurement. The results were obtained from various sound intensities and different frequencies. The outcomes comparing to conventional HAs were conflicting. Nevertheless, all results comparing to unaided condition showed improvement and showed a subjective improvement of quality of life.There are still some problems to be solved, mainly related to device functioning and price. Due to the relatively few publications available and small sample sizes, we must be careful in extrapolating these results to a broader population. Additionally, none of all these studies represented level high levels of evidence (i.e. randomized controlled trials.

  13. XMM-Newton Observations of the 2003 X-ray Minimum of Eta Carinae

    CERN Document Server

    Hamaguchi, K; Gull, T R; White, N E; Damineli, A; Davidson, K

    2004-01-01

    The XMM-Newton X-ray observatory took part in the multi-wavelength observing campaign of the massive, evolved star Eta Carinae in 2003 during its recent X-ray minimum. This paper reports on the results of these observations, mainly from the aspect of spectral change. Hard X-ray emission from the point source of Eta Carinae was detected even during the minimum. During the minimum the observed flux above 3 keV was ~3e-12 ergs cm-2 s-1, which is about one percent of the flux before the minimum. Changes in the spectral shape revealed two X-ray emission components in the central point source. One component is non-variable and has relatively cool plasma of kT~1 keV and moderate absorption, NH~5e22 cm-2. The plasma is probably located far from the star, possibly produced by the high speed polar wind from Eta Carinae. The other high temperature component has kT~5 keV and is strongly variable. This component shows an increase in the apparent column density from 5e22 cm-2 to 2e23 cm-2, probably originating near the hea...

  14. Stellar populations in the Carina region: The Galactic plane at l = 291

    CERN Document Server

    Molina-Lera, J A; Gamen, R; Costa, E; Carraro, G

    2016-01-01

    Previous studies of the Carina region have revealed its complexity and richness as well as a significant number of early-type stars. In many cases, these studies only concentrated on the central region or were not homogeneous. This latter aspect, in particular, is crucial because very different ages and distances for key clusters have been claimed in recent years. The aim of this work is to study in detail an area of the Galactic plane in Carina. We analyze the properties of different stellar populations and focus on a sample of open clusters and their population of YSOs and highly reddened early stars. We also studied the stellar mass distribution in these clusters and the possible scenario of their formation. Finally, we outline the Galactic spiral structure in this direction. We obtained photometric data for six young open clusters located in Carina at l = 291, and their adjacent stellar fields, which we complemented with spectroscopic observations of a few selected targets. We also culled additional infor...

  15. A Comprehensive, Wide-Field Study of Pulsating Stars in the Carina Dwarf Spheroidal Galaxy

    CERN Document Server

    Vivas, A Katherina

    2013-01-01

    We report the detection of 388 pulsating variable stars (and some additional miscellaneous variables) in the Carina dSph galaxy over an area covering the full visible extent of the galaxy and extending a few times beyond its photometric (King) tidal radius along the direction of its major axis. Included in this total are 340 newly discovered dwarf Cepheids which are mostly located ~2.5 magnitudes below the horizontal branch and have very short periods (<0.1 days) typical of their class and consistent with their location on the upper part of the extended main sequence of the younger populations of the galaxy. Several extra-tidal dwarf cepheids were found in our survey up to a distance of ~1 degree from the center of Carina. Our sample also includes RR Lyrae stars and anomalous Cepheids some of which were found outside the galaxy's tidal radius as well. This supports past works that suggests Carina is undergoing tidal disruption. We use the period-luminosity relationship for dwarf Cepheids to estimate a dist...

  16. The Radio Spectral Index of the Crab Nebula

    Science.gov (United States)

    1997-11-20

    We present the results of a new, comprehensive investigation of the radio spectral index of the Crab Nebula supernova remnant. New data at 74 MHz are...thermal material in the Crab Nebula’s filaments. Apart from some possible renewed acceleration occurring in the wisps, the dominant accelerator of relativistic electrons in the Crab Nebula is the pulsar itself.

  17. Detection of CO Outflow in Rotating Cores

    Institute of Scientific and Technical Information of China (English)

    Xin Guan; Yue-Fang Wu

    2008-01-01

    We investigate the effect of bulk motion on the detection of molecular outflows in the sources S 146, GGD27, and IRAS 22566+5830. The traditional techniques do allow for bulk motions or systematic VLSR shifts of the core emissions, which may cause contamination of the high velocity gas emissions, and outflows may either fail to be detected or have their properties miscalculated. We used a program to follow the systematic shift of VLSR and better results have been obtained.

  18. Fast cold gas in hot AGN outflows

    CERN Document Server

    Costa, Tiago; Haehnelt, Martin

    2014-01-01

    Observations of the emission from spatially extended cold gas around bright high-redshift QSOs reveal surprisingly large velocity widths exceeding 2000 km s^(-1), out to projected distances as large as 30 kpc. The high velocity widths have been interpreted as the signature of powerful AGN-driven outflows. Naively, these findings appear in tension with hydrodynamic models in which AGN-driven outflows are energy-driven and thus very hot with typical temperatures T = 10^6-7 K. Using the moving-mesh code Arepo, we perform 'zoom-in' cosmological simulations of a z = 6 QSO and its environment, following black hole growth and feedback via energy-driven outflows. In the simulations, the QSO host galaxy is surrounded by a clumpy circum-galactic medium pre-enriched with metals due to supernovae-driven galactic outflows. As a result, part of the AGN-driven hot outflowing gas can cool radiatively, leading to large amounts (> 10^9 M_sun) of cold gas comoving with the hot bipolar outflow. This results in velocity widths of...

  19. Theory of photospheric emission from relativistic outflows

    CERN Document Server

    Ruffini, R; Vereshchagin, G V

    2013-01-01

    (shortened) In this paper we reexamine the optical depth of ultrarelativistic spherically symmetric outflows and reevaluate the photospheric radius for each model during both the acceleration and coasting phases. It is shown that for both the wind and the shell models there are two asymptotic solutions for the optical depth during the coasting phase of the outflow. In particular we show that quite counterintuitively a geometrically thin shell may appear as a thick wind for photons propagating inside it. For this reason we introduce notions of photon thick and photon thin outflows, which appear more general and better physically motivated with respect to winds and shells. Photosphere of relativistic outflow is a dynamic surface. We study its geometry and find that the photosphere of photon thin outflow has always a convex shape, while in the photon thick one it is initially convex (there is always a photon thin layer in any outflow) and then it becomes concave asymptotically approaching the photosphere of an i...

  20. Quantifying Supernovae-Driven Multiphase Galactic Outflows

    CERN Document Server

    Li, Miao; Ostriker, Jeremiah P

    2016-01-01

    Galactic outflows are ubiquitously observed in star-forming disk galaxies and are critical for galaxy formation. Supernovae (SNe) play the key role in driving the outflows, but there is no consensus as to how much energy, mass and metal they can launch out of the disk. We perform 3D, high-resolution hydrodynamic simulations to study SNe-driven outflows from stratified media. Assuming SN rate scales with gas surface density $\\Sigma_{\\rm{gas}}$ as in the Kennicutt-Schmidt (KS) relation, we find the mass loading factor, defined as the mass outflow flux divided by the star formation surface density, decreases with increasing $\\Sigma_{\\rm{gas}}$ as $\\propto \\Sigma^{-0.61}_{\\rm{gas}}$. Approximately $\\Sigma_{\\rm{gas}} \\lesssim$ 50 $M_\\odot/pc^2$ marks when the mass loading factor $\\gtrsim$1. About 10-50\\% of the energy and 40-80\\% of the metals produced by SNe end up in the outflows. The tenuous hot phase ($T>3\\times 10^5$ K) carries the majority of the energy and metals in outflows. We discuss how various physical...

  1. Most Detailed Image of the Crab Nebula

    Science.gov (United States)

    2005-01-01

    This new Hubble image -- one among the largest ever produced with the Earth-orbiting observatory -- shows the most detailed view so far of the entire Crab Nebula ever made. The Crab is arguably the single most interesting object, as well as one of the most studied, in all of astronomy. The image is the largest image ever taken with Hubble's WFPC2 workhorse camera. The Crab Nebula is one of the most intricately structured and highly dynamical objects ever observed. The new Hubble image of the Crab was assembled from 24 individual exposures taken with the NASA/ESA Hubble Space Telescope and is the highest resolution image of the entire Crab Nebula ever made.

  2. Monitoring the Crab Nebula with LOFT

    Science.gov (United States)

    Wilson-Hodge, Colleen A.

    2012-01-01

    From 2008-2010, the Crab Nebula was found to decline by 7% in the 15-50 keV band, consistently in Fermi GBM, INTEGRAL IBIS, SPI, and JEMX, RXTE PCA, and Swift BAT. From 2001-2010, the 15-50 keV flux from the Crab Nebula typically varied by about 3.5% per year. Analysis of RXTE PCA data suggests possible spectral variations correlated with the flux variations. I will present estimates of the LOFT sensitivity to these variations. Prior to 2001 and since 2010, the observed flux variations have been much smaller. Monitoring the Crab with the LOFT WFM and LAD will provide precise measurements of flux variations in the Crab Nebula if it undergoes a similarly active episode.

  3. The expansion proper motions of the extraordinary giant lobes of the planetary nebula KjPn 8 revisited

    CERN Document Server

    Boumis, Panos

    2013-01-01

    The primary aim is to establish a firm value for the distance to the extraordinary planetary nebula KjPn 8. Secondary aims are to measure the ages of the three giant lobes of this object as well as estimate the energy in the eruption, that caused the most energetic outflow, for comparison with that of an intermediate luminosity optical transient (ILOT). For these purposes a mosaic of images in the Halpha+[N II] optical emission lines has been obtained with the new Aristarchos telescope in 2011 for comparison with the images of the KjPn 8 giant lobes present on the POSSI-R 1954 and POSSII-R 1991 plates. Expansion proper motions of features over this 57 yr baseline in the outflows are present. Using these, a firm distance to KjPn 8 of 1.8 +- 0.3 kpc has been derived for now the angle of the latest outflow to the sky has been established from HST imagery of the nebular core. Previously, the uncertain predictions of a bow-shock model were used for this purpose. The dynamical ages of the three separate outflows th...

  4. A Giant Lyα Nebula in the Core of an X-Ray Cluster at Z = 1.99: Implications for Early Energy Injection

    Science.gov (United States)

    Valentino, Francesco; Daddi, Emanuele; Finoguenov, Alexis; Strazzullo, Veronica; Le Brun, Amandine; Vignali, Cristian; Bournaud, Frédéric; Dickinson, Mark; Renzini, Alvio; Béthermin, Matthieu; Zanella, Anita; Gobat, Raphaël; Cimatti, Andrea; Elbaz, David; Onodera, Masato; Pannella, Maurilio; Sargent, Mark; Arimoto, Nobuo; Carollo, Marcella; Starck, Jean-Luc

    2016-09-01

    We present the discovery of a giant ≳100 kpc Lyα nebula detected in the core of the X-ray emitting cluster CL J1449+0856 at z = 1.99 through Keck/LRIS narrow-band imaging. This detection extends the known relation between Lyα nebulae and overdense regions of the universe to the dense core of a 5-7 × 1013 M ⊙ cluster. The most plausible candidates to power the nebula are two Chandra-detected AGN host cluster members, while cooling from the X-ray phase and cosmological cold flows are disfavored primarily because of the high Lyα to X-ray luminosity ratio ({L}{Lyα }/{L}{{X}}≈ 0.3, ≳10-1000 times higher than in local cool-core clusters) and by current modeling. Given the physical conditions of the Lyα-emitting gas and the possible interplay with the X-ray phase, we argue that the Lyα nebula would be short-lived (≲10 Myr) if not continuously replenished with cold gas at a rate of ≳1000 M ⊙ yr-1. We investigate the possibility that cluster galaxies supply the required gas through outflows and we show that their total mass outflow rate matches the replenishment necessary to sustain the nebula. This scenario directly implies the extraction of energy from galaxies and its deposition in the surrounding intracluster medium (ICM), as required to explain the thermodynamic properties of local clusters. We estimate an energy injection of the order of ≈ 2 {{keV}} per particle in the ICM over a 2 Gyr interval. In our baseline calculation, AGNs provide up to 85% of the injected energy and two-thirds of the mass, while the rest is supplied by supernovae-driven winds.

  5. Monitoring the Orion Nebula Cluster

    Science.gov (United States)

    Reipurth, Bo

    The VYSOS (Variable Young Stars Optical Survey) project has at its disposal five small telescopes: a 5-inch and a 20-inch robotic optical imaging telescope in Hawaii funded by the NSF, and a 6-inch robotic optical imaging telescope, a 32-inch robotic infrared imaging telescope, and a 60-inch optical spectroscopic telescope in Chile, funded and operated from Germany. Through an agreement between the leaders of the two sites (B. Reipurth and R. Chini), it has been decided to devote a significant fraction of time on these facilities to a large Key Project, conducting a massive monitoring survey of the Orion Nebula Cluster. The vast data streams are being reduced through automated customized pipelines. The applicant seeks funding to employ a postdoc and an undergraduate assistant to work at the University of Hawaii and collaborate on the analysis of the data. Virtually all young stars are variable, with a wide range of amplitudes and characteristic timescales. This is mainly due to accretion shocks as material from circumstellar disks fall onto the stars along magnetic funnel flows, but also giant star spots, magnetic flares, occultations by orbiting dust condensations, and eclipses by companions can modulate the light from the nascent star. It is increasingly recognized that the rather static view of pre-main sequence evolution that has prevailed for many years is misleading, and that time-dependent phenomena may hold the key to an understanding of the way young stars grow and their circumstellar environments evolve. The VYSOS project is designed to bring sophisticated modern techniques to bear on the long neglected problem of variability in young solar type stars. To interpret the observations they will be compared to sophisticated MHD models of circumstellar disks around young stars. The Orion Nebula Cluster is the nearest rich region of star formation, and numerous, albeit heterogeneous, studies exist of the cluster members. The present study will provide the first

  6. Dust Extinction in Compact Planetary Nebulae

    OpenAIRE

    Lee, TH; Kwok, S.

    2005-01-01

    The effects of dust extinction on the departure from axisymmetry in the morphology of planetary nebulae (PNs) are investigated through a comparison of the radio free-free emission and hydrogen recombination line images. The dust extinction maps from five compact PNs are derived using high-resolution (̃0"1) Hα and radio maps of the HST and VLA. These extinction maps are then analyzed by an ellipsoidal shell ionization model including the effects of dust extinction to infer the nebulae's intrin...

  7. Ultraviolet studies of the Crab Nebula

    Science.gov (United States)

    Talavera, A.

    2017-03-01

    The Crab Nebula (Messier 1) is one of the most observed sources with the XMM-Newton space telescope of ESA. The Crab and its related pulsar are a calibration source for the on-board X-rays cameras. There are around 80 observations between 2000 and 2015. In this observations, the XMM-Newton Optical and UV Monitor (OM) has also been used. We present a preliminary study of the Crab using images obtained the OM UV filters at 291, 231 and 212 nm. Photometric data for the pulsar (PSR0531+21), created in the supernova event of AD 1054 origin of the nebula, are also presented

  8. Stellar populations in the Carina region. The Galactic plane at l = 291°

    Science.gov (United States)

    Molina-Lera, J. A.; Baume, G.; Gamen, R.; Costa, E.; Carraro, G.

    2016-08-01

    Context. Previous studies of the Carina region have revealed its complexity and richness as well as a significant number of early-type stars. However, in many cases, these studies only concentrated on the central region (Trumpler 14/16) or were not homogeneous. This latter aspect, in particular, is crucial because very different ages and distances for key clusters have been claimed in recent years. Aims: The aim of this work is to study in detail an area of the Galactic plane in Carina, eastward η Carina. We analyze the properties of different stellar populations and focus on a sample of open clusters and their population of young stellar objects and highly reddened early stars. We also studied the stellar mass distribution in these clusters and the possible scenario of their formation. Finally, we outline the Galactic spiral structure in this direction. Methods: We obtained deep and homogeneous photometric data (UBVIKC) for six young open clusters: NGC 3752, Trumpler 18, NGC 3590, Hogg 10, 11, and 12, located in Carina at l ~ 291°, and their adjacent stellar fields, which we complemented with spectroscopic observations of a few selected targets. We also culled additional information from the literature, which includes stellar spectral classifications and near-infrared photometry from 2MASS. We finally developed a numerical code that allowed us to perform a homogeneous and systematic analysis of the data. Our results provide more reliable estimates of distances, color excesses, masses, and ages of the stellar populations in this direction. Results: We estimate the basic parameters of the studied clusters and find that they identify two overdensities of young stellar populations located at about 1.8 kpc and 2.8 kpc, with EB - V ~ 0.1 - 0.6. We find evidence of pre-main-sequence populations inside them, with an apparent coeval stellar formation in the most conspicuous clusters. We also discuss apparent age and distance gradients in the direction NW-SE. We study the

  9. Active Galactic Nuclei Feedback and Galactic Outflows

    Science.gov (United States)

    Sun, Ai-Lei

    Feedback from active galactic nuclei (AGN) is thought to regulate the growth of supermassive black holes (SMBHs) and galaxies. The most direct evidence of AGN feedback is probably galactic outflows. This thesis addresses the link between SMBHs and their host galaxies from four different observational perspectives. First, I study the local correlation between black hole mass and the galactic halo potential (the MBH - Vc relation) based on Very Large Array (VLA) HI observations of galaxy rotation curves. Although there is a correlation, it is no tighter than the well-studied MBH - sigma* relation between the black hole mass and the potential of the galactic bulge, indicating that physical processes, such as feedback, could link the evolution of the black hole to the baryons in the bulge. In what follows, I thus search for galactic outflows as direct evidence of AGN feedback. Second, I use the Atacama Large Millimeter Array (ALMA) to observe a luminous obscured AGN that hosts an ionized galactic outflow and find a compact but massive molecular outflow that can potentially quench the star formation in 10. 6 years.The third study extends the sample of known ionized outflows with new Magellan long-slit observations of 12 luminous obscured AGN. I find that most luminous obscured AGN (Lbol > 1046 ergs s-1) host ionized outflows on 10 kpc scales, and the size of the outflow correlates strongly with the luminosity of the AGN. Lastly, to capitalize on the power of modern photometric surveys, I experiment with a new broadband imaging technique to study the morphology of AGN emission line regions and outflows. With images from the Sloan Digital Sky Survey (SDSS), this method successfully constructs images of the [OIII]lambda5007 emission line and reveals hundreds of extended emission-line systems. When applied to current and future surveys, such as the Large Synoptic Survey Telescope (LSST), this technique could open a new parameter space for the study of AGN outflows. In

  10. A robust measurement of the mass outflow rate of the galactic outflow from NGC 6090

    Science.gov (United States)

    Chisholm, John; Tremonti Christy, A.; Leitherer, Claus; Chen, Yanmei

    2016-11-01

    To evaluate the impact of stellar feedback, it is critical to estimate the mass outflow rates of galaxies. Past estimates have been plagued by uncertain assumptions about the outflow geometry, metallicity, and ionization fraction. Here we use Hubble Space Telescope ultraviolet spectroscopic observations of the nearby starburst NGC 6090 to demonstrate that many of these quantities can be constrained by the data. We use the Si IV absorption lines to calculate the scaling of velocity (v), covering fraction (Cf), and density with distance from the starburst (r), assuming the Sobolev optical depth and a velocity law of the form: v ∝ (1 - Ri/r)β (where Ri is the inner outflow radius). We find that the velocity (β = 0.43) is consistent with an outflow driven by an r-2 force with the outflow radially accelerated, while the scaling of the covering fraction (Cf ∝ r-0.82) suggests that cool clouds in the outflow are in pressure equilibrium with an adiabatically expanding medium. We use the column densities of four weak metal lines and CLOUDY photoionization models to determine the outflow metallicity, the ionization correction, and the initial density of the outflow. Combining these values with the profile fitting, we find Ri = 63 pc, with most of the mass within 300 pc of the starburst. Finally, we find that the maximum mass outflow rate is 2.3 M⊙ yr-1 and the mass-loading factor (outflow divided by the star formation rate) is 0.09, a factor of 10 lower than the value calculated using common assumptions for the geometry, metallicity, and ionization structure of the outflow.

  11. Bursty star formation feedback and cooling outflows

    Science.gov (United States)

    Suarez, Teresita; Pontzen, Andrew; Peiris, Hiranya V.; Slyz, Adrianne; Devriendt, Julien

    2016-10-01

    We study how outflows of gas launched from a central galaxy undergoing repeated starbursts propagate through the circum-galactic medium (CGM), using the simulation code RAMSES. We assume that the outflow from the disc can be modelled as a rapidly moving bubble of hot gas at ˜1 kpc above disc, then ask what happens as it moves out further into the halo around the galaxy on ˜100 kpc scales. To do this, we run 60 two-dimensional simulations scanning over parameters of the outflow. Each of these is repeated with and without radiative cooling, assuming a primordial gas composition to give a lower bound on the importance of cooling. In a large fraction of radiative-cooling cases we are able to form rapidly outflowing cool gas from in situ cooling of the flow. We show that the amount of cool gas formed depends strongly on the `burstiness' of energy injection; sharper, stronger bursts typically lead to a larger fraction of cool gas forming in the outflow. The abundance ratio of ions in the CGM may therefore change in response to the detailed historical pattern of star formation. For instance, outflows generated by star formation with short, intense bursts contain up to 60 per cent of their gas mass at temperatures <5 × 104 K; for near-continuous star formation, the figure is ≲5 per cent. Further study of cosmological simulations, and of idealized simulations with e.g. metal-cooling, magnetic fields and/or thermal conduction, will help to understand the precise signature of bursty outflows on observed ion abundances.

  12. IUE observations of high velocity gas towards the M16 nebula

    Science.gov (United States)

    Welsh, B. Y.

    1984-03-01

    The star HD 168183, which is part of the giant H II region-molecular cloud complex of M16 (NGC 6611), has been observed at high resolution using the IUE satellite. High velocity interstellar absorption components have been detected at velocities of -83, -38 and +40 km s-1 and it is proposed that a stellar wind-driven shock-front, interacting with the ambient neutral interstellar gas, is responsible for such complex velocity structure. Strong absorption from five of the 12C16O UV molecular lines has also been detected and the present UV absorption line data seem consistent with radio observations of M16 in which the Tenorio-Tagle 'champagne' model has been invoked to explain the ionized and neutral gas outflows from the nebula.

  13. Flows along cometary tails in the Helix planetary nebula NGC 7293

    CERN Document Server

    Meaburn, John

    2009-01-01

    Previous velocity images which reveal flows of ionized gas along the most prominent cometary tail (from Knot 38) in the Helix planetary nebula are compared with that taken at optical wavelengths with the Hubble Space Telescope and with an image in the emission from molecular hydrogen. The flows from the second most prominent tail from Knot 14 are also considered. The kinematics of the tail from the more complex Knot 32, shown here for the first time, also reveals an acceleration away from the central star. All of the tails are explained as accelerating ionized flows of ablated material driven by the previous, mildly supersonic, AGB wind from the central star. The longest tail of ionized gas, even though formed by this mechanism in a very clumpy medium, as revealed by the emission from molecular hydrogen, appears to be a coherent outflowing feature.

  14. Pressurized groundwater outflow experiments and numerical modeling for outflow channels on Mars

    NARCIS (Netherlands)

    Marra, Wouter A.; Hauber, Ernst; McLelland, Stuart J.; Murphy, Brendan J.; Parsons, Daniel R.; Conway, Susan J.; Roda, Manuel; Govers, Rob; Kleinhans, Maarten G.

    2014-01-01

    The landscape of Mars shows incised channels that often appear abruptly in the landscape, suggesting a groundwater source. However, groundwater outflow processes are unable to explain the reconstructed peak discharges of the largest outflow channels based on their morphology. Therefore, there is a d

  15. Protostellar Outflows and Radiative Feedback from Massive Stars. II. Feedback, Star Formation Efficiency, and Outflow Broadening

    CERN Document Server

    Kuiper, Rolf; Yorke, Harold W

    2016-01-01

    We perform two-dimensional axially symmetric radiation-hydrodynamic simulations to assess the impact of outflows and radiative force feedback from massive protostars by varying when the protostellar outflow starts, the ratio of ejection to accretion rates, and the strength of the wide angle disk wind component. The star formation efficiency, i.e. the ratio of final stellar mass to initial core mass, is dominated by radiative forces and the ratio of outflow to accretion rates. Increasing this ratio has three effects: First, the protostar grows slower with a lower luminosity at any given time, lowering radiative feedback. Second, bipolar cavities cleared by the outflow are larger, further diminishing radiative feedback on disk and core scales. Third, the higher momentum outflow sweeps up more material from the collapsing envelope, decreasing the protostar's potential mass reservoir via entrainment. The star formation efficiency varies with the ratio of ejection to accretion rates from 50% in the case of very we...

  16. INTERNAL PROPER MOTIONS IN THE ESKIMO NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    García-Díaz, Ma. T.; Gutiérrez, L.; Steffen, W.; López, J. A. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Km 103 Carretera Tijuana-Ensenada, 22860 Ensenada, B.C. (Mexico); Beckman, J., E-mail: tere@astro.unam.mx, E-mail: leonel@astro.unam.mx, E-mail: wsteffen@astro.unam.mx, E-mail: jal@astro.unam.mx, E-mail: jeb@iac.es [Instituto de Astrofísica de Canarias, La Laguna, Tenerife (Spain)

    2015-01-10

    We present measurements of internal proper motions at more than 500 positions of NGC 2392, the Eskimo Nebula, based on images acquired with WFPC2 on board the Hubble Space Telescope at two epochs separated by 7.695 yr. Comparisons of the two observations clearly show the expansion of the nebula. We measured the amplitude and direction of the motion of local structures in the nebula by determining their relative shift during that interval. In order to assess the potential uncertainties in the determination of proper motions in this object, in general, the measurements were performed using two different methods, used previously in the literature. We compare the results from the two methods, and to perform the scientific analysis of the results we choose one, the cross-correlation method, because it is more reliable. We go on to perform a ''criss-cross'' mapping analysis on the proper motion vectors, which helps in the interpretation of the velocity pattern. By combining our results of the proper motions with radial velocity measurements obtained from high resolution spectroscopic observations, and employing an existing 3D model, we estimate the distance to the nebula to be 1.3 kpc.

  17. Planetary nebulae abundances and stellar evolution

    CERN Document Server

    Pottasch, S R

    2006-01-01

    A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are the same as HII regions and early type star abundance gradients. The abundance of these elements predicted from these gradients at the distance of the Sun from the center are exactly the solar abundance. Sulfur is the exception to this; the reason for this is discussed. The higher solar neon abundance is confirmed; this is discussed in terms of the results of helioseismology. Evidence is presented for oxygen destruction via ON cycling having occurred in the progenitors of four planetary nebulae with bilobal structure. These progenitor stars had a high mass, probably greater than 5 solar masses. This is deduced from the high values of He/H and N/H found in these nebulae. Formation of nitrogen, helium and carbon are discussed. The high mass progenitors which showed oxygen de...

  18. Argon and neon in Galactic nebulae

    Science.gov (United States)

    Simpson, Janet P.; Bregman, Jesse D.; Dinerstein, H. L.; Lester, Dan F.; Rank, David M.; Witteborn, F. C.; Wooden, D. H.

    1995-01-01

    KAO observations of the 6.98 micron line of (Ar II), and KAO and ground-based observations of the 8.99 micron line of (Ar III) and the 12.8 micron line of (Ne II) are presented for a number of Galactic H II regions and planetary nebulae.

  19. Cerebral venous outflow and cerebrospinal fluid dynamics

    Directory of Open Access Journals (Sweden)

    Clive B. Beggs

    2014-12-01

    Full Text Available In this review, the impact of restricted cerebral venous outflow on the biomechanics of the intracranial fluid system is investigated. The cerebral venous drainage system is often viewed simply as a series of collecting vessels channeling blood back to the heart. However there is growing evidence that it plays an important role in regulating the intracranial fluid system. In particular, there appears to be a link between increased cerebrospinal fluid (CSF pulsatility in the Aqueduct of Sylvius and constricted venous outflow. Constricted venous outflow also appears to inhibit absorption of CSF into the superior sagittal sinus. The compliance of the cortical bridging veins appears to be critical to the behaviour of the intracranial fluid system, with abnormalities at this location implicated in normal pressure hydrocephalus. The compliance associated with these vessels appears to be functional in nature and dependent on the free egress of blood out of the cranium via the extracranial venous drainage pathways. Because constricted venous outflow appears to be linked with increased aqueductal CSF pulsatility, it suggests that inhibited venous blood outflow may be altering the compliance of the cortical bridging veins.

  20. Evolution of Mass Outflow in Protostars

    CERN Document Server

    Watson, Dan M; Fischer, William J; Forrest, W J; Manoj, P; Megeath, S Thomas; Melnick, Gary J; Najita, Joan; Neufeld, David A; Sheehan, Patrick D; Stutz, Amelia M; Tobin, John J

    2015-01-01

    We have surveyed 84 Class 0, Class I, and flat-spectrum protostars in mid-infrared [Si II], [Fe II] and [S I] line emission, and 11 of these in far-infrared [O I] emission. We use the results to derive their mass outflow rates. Thereby we observe a strong correlation of mass outflow rates with bolometric luminosity, and with the inferred mass accretion rates of the central objects, which continues through the Class 0 range the trend observed in Class II young stellar objects. Along this trend from large to small mass-flow rates, the different classes of young stellar objects lie in the sequence Class 0 -- Class I/flat-spectrum -- Class II, indicating that the trend is an evolutionary sequence in which mass outflow and accretion rates decrease together with increasing age, while maintaining rough proportionality. The survey results include two which are key tests of magnetocentrifugal outflow-acceleration mechanisms: the distribution of the outflow/accretion branching ratio b, and limits on the distribution of...

  1. Bursty star formation feedback and cooling outflows

    CERN Document Server

    Suarez, Teresita; Peiris, Hiranya V; Slyz, Adrianne; Devriendt, Julien

    2016-01-01

    We study how outflows of gas launched from a central galaxy undergoing repeated starbursts propagate through the circumgalactic medium (CGM), using the simulation code RAMSES. We assume that the outflow from the disk can be modelled as a rapidly moving bubble of hot gas at $\\mathrm{\\sim1\\;kpc}$ above disk, then ask what happens as it moves out further into the halo around the galaxy on $\\mathrm{\\sim 100\\;kpc}$ scales. To do this we run 60 two-dimensional simulations scanning over parameters of the outflow. Each of these is repeated with and without radiative cooling, assuming a primordial gas composition to give a lower bound on the importance of cooling. In a large fraction of radiative-cooling cases we are able to form rapidly outflowing cool gas from in situ cooling of the flow. We show that the amount of cool gas formed depends strongly on the 'burstiness' of energy injection; sharper, stronger bursts typically lead to a larger fraction of cool gas forming in the outflow. The abundance ratio of ions in th...

  2. HIGH-RESOLUTION CO OBSERVATION OF THE CARBON STAR CIT 6 REVEALING THE SPIRAL STRUCTURE AND A NASCENT BIPOLAR OUTFLOW

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyosun; Liu, Sheng-Yuan; Hirano, Naomi; Zhao-Geisler, Ronny; Trejo, Alfonso; Yen, Hsi-Wei; Taam, Ronald E.; Kemper, Francisca [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Kim, Jongsoo; Byun, Do-Young; Liu, Tie, E-mail: hkim@asiaa.sinica.edu.tw [Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)

    2015-11-20

    CIT 6 is a carbon star in the transitional phase from the asymptotic giant branch (AGB) to the protoplanetary nebulae (pPNs). Observational evidences of two point sources in the optical, circumstellar arc segments in an HC{sub 3}N line emission, and a bipolar nebula in near-infrared provide strong support for the presence of a binary companion. Hence, CIT 6 is very attractive for studying the role of companions in the AGB–pPN transition. We have carried out high-resolution {sup 12}CO J = 2–1 and {sup 13}CO J = 2–1 observations of CIT 6 with the Submillimeter Array combined with the Submillimeter Telescope (single-dish) data. The {sup 12}CO channel maps reveal a spiral-shell pattern connecting the HC{sub 3}N segments in a continuous form and an asymmetric outflow corresponding to the near-infrared bipolar nebula. Rotation of the {sup 12}CO channel peak position may be related to the inner spiral winding and/or the bipolar outflow. An eccentric orbit binary is suggested for the presence of an anisotropic mass loss to the west and a double spiral pattern. The lack of interarm emission to the west may indicate a feature corresponding to the periastron passage of a highly eccentric orbit of the binary. Spatially averaged radial and spectral profiles of {sup 12}CO J = 2–1 and {sup 13}CO J = 2–1 are compared with simple spherical radiative transfer models, suggesting a change of {sup 12}CO/{sup 13}CO abundance ratio from ∼30 to ∼50 inward in the CSE of CIT 6. The millimeter continuum emission is decomposed into extended dust thermal emission (spectral index ∼ −2.4) and compact emission from radio photosphere (spectral index ∼ −2.0)

  3. On the possible wind nebula of magnetar Swift J1834.9-0846: a magnetism-powered synchrotron nebula

    CERN Document Server

    Tong, H

    2016-01-01

    Recently, the magnetar Swift J1834.9$-$0846 is reported to have a possible wind nebula. It is shown that both the magnetar and its wind nebula are understandable in the wind braking scenario. The magnetar's rotational energy loss rate is not enough. The required particle luminosity should be about $10^{36} \\,\\rm erg \\,s^{-1}$ to $10^{38} \\,\\rm erg \\,s^{-1}$. It is obtained in three different approaches: considering wind braking of Swift J1834.9$-$0846; the spectral and spatial observations of the wind nebula; and an empirical upper bound on wind nebula X-ray luminosity. The nebula magnetic field is be about $10^{-4} \\,\\rm G$. The possible wind nebula of Swift J1834.9$-$0846 should be a magnetar wind nebula. It is powered by the magnetic energy release of the magnetar.

  4. On the possible wind nebula of magnetar Swift J1834.9–0846: a magnetism-powered synchrotron nebula

    Science.gov (United States)

    Tong, Hao

    2016-09-01

    Recently, the magnetar Swift J1834.9–0846 has been reported to have a possible wind nebula. It is shown that both the magnetar and its wind nebula are understandable in the wind braking scenario. The magnetar's rotational energy loss rate is not enough to power the particle luminosity. The required particle luminosity should be about 1036 erg s‑1 to 1038 erg s‑1. It is obtained in three different approaches: considering wind braking of Swift J1834.9–0846 the spectral and spatial observations of the wind nebula; and an empirical upper bound on wind nebula X-ray luminosity. The nebula magnetic field is about 10‑4 G. The possible wind nebula of Swift J1834.9–0846 should be a magnetar wind nebula. It is powered by the magnetic energy released from the magnetar.

  5. Observations of Protostellar Outflow Feedback in Clustered Star Formation

    CERN Document Server

    Nakamura, Fumitaka

    2015-01-01

    We discuss the role of protostellar outflow feedback in clustered star formation using the observational data of recent molecular outflow surveys toward nearby cluster-forming clumps. We found that for almost all clumps, the outflow momentum injection rate is significantly larger than the turbulence dissipation rate. Therefore, the outflow feedback is likely to maintain supersonic turbulence in the clumps. For less massive clumps such as B59, L1551, and L1641N, the outflow kinetic energy is comparable to the clump gravitational energy. In such clumps, the outflow feedback probably affects significantly the clump dynamics. On the other hand, for clumps with masses larger than about 200 M$_\\odot$, the outflow kinetic energy is significantly smaller than the clump gravitational energy. Since the majority of stars form in such clumps, we conclude that outflow feedback cannot destroy the whole parent clump. These characteristics of the outflow feedback support the scenario of slow star formation.

  6. Dusty globules in the Crab Nebula

    Science.gov (United States)

    Grenman, T.; Gahm, G. F.; Elfgren, E.

    2017-03-01

    Context. Dust grains are widespread in the Crab Nebula. A number of small, dusty globules, are visible as dark spots against the background of continuous synchrotron emission in optical images. Aims: Our aim is to catalogue such dusty globules and investigate their properties. Methods: From existing broad-band images obtained with the Hubble Space Telescope, we located 92 globules, for which we derived positions, dimensions, orientations, extinctions, masses, proper motions, and their distributions. Results: The globules have mean radii ranging from 400 to 2000 AU and are not resolved in current infrared images of the nebula. The extinction law for dust grains in these globules matches a normal interstellar extinction law. Derived masses of dust range from 1 to 60 × 10-6M⊙, and the total mass contained in globules constitute a fraction of approximately 2% or less of the total dust content of the nebula. The globules are spread over the outer part of the nebula, and a fraction of them coincide in position with emission filaments, where we find elongated globules that are aligned with these filaments. Only 10% of the globules are coincident in position with the numerous H2-emitting knots found in previous studies. All globules move outwards from the centre with transversal velocities of 60 to 1600 km s-1, along with the general expansion of the remnant. We discuss various hypotheses for the formation of globules in the Crab Nebula. Based on observations collected with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute.

  7. Results of a Deep Chandra Observation of the Crab Nebula and Pulsar

    Science.gov (United States)

    Weisskopf, M. C.; Becker, W.; Elsner, R. F.; Juda, M.; Kolodziejczak, J.; Murray, S. S.; ODell, S.; Paerels, F.; Shibazaki, N.; Swartz, D.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The Crab Nebula and pulsar were observed for a total of 150 ksec with the LETG/HRC-S combination aboard the Chandra X-Ray Observatory in 2000, January and February. One of the principal aims of the experiment was to study the emission from the pulsar as a function of pulse phase. Neutron stars are believed to be formed with core temperatures of 10(exp 11) K. As the pulsar is the best studied of the young known neutron stars with an age of only 940 yrs, it should be possible to observe thermal emission from the hot stellar surface which in turn constrains equations of state. The pulsar, on the other hand, is a powerful non-thermal emitter, powering an X-ray bright synchrotron nebula which, in Einstein and ROSAT observations, overshadowed the fainter thermal surface emission. Making use of the high angular resolution provided by Chandra we were able to detect X-rays from the Crab-pulsar at all pulse phases. We discuss whether this detection is indeed of thermal emission or of a faint synchrotron component of the pulsed emission from the magnetosphere. We further comment on dynamical effects observed in the pulsar-wind outflow and the analysis of the LETG spectral data, especially near the oxygen edge.

  8. From Bipolar to Elliptical: Simulating the Morphological Evolution of Planetary Nebulae

    CERN Document Server

    Huarte-Espinosa, Martín; Balick, Bruce; Blackman, Eric G; De Marco, Orsola; Kastner, Joel H; Sahai, Raghvendra

    2011-01-01

    The majority of Proto-planetary nebulae (PPN) are observed to have bipolar morphologies. The majority of mature PN are observed to have elliptical shapes. In this paper we address the evolution of PPN/PN morphologies attempting to understand if a transition from strongly bipolar to elliptical shape can be driven by changes in the parameters of the mass loss process. To this end we present 2.5D hydrodynamical simulations of mass loss at the end stages of stellar evolution for intermediate mass stars. We track changes in wind velocity, mass loss rate and mass loss geometry. In particular we focus on the transition from mass loss dominated by a short duration jet flow (driven during the PPN phase) to mass loss driven by a spherical fast wind (produced by the central star of the PN). We address how such changes in outflow characteristics can change the nebula from a bipolar to an elliptical morphology. Our results show that including a period of jet formation in the temporal sequence of PPN to PN produces realist...

  9. Tearing the Veil: interaction of the Orion Nebula with its neutral environment

    CERN Document Server

    van der Werf, Paul P; O'Dell, C R

    2012-01-01

    We present HI 21cm observations of the Orion Nebula, obtained with the Karl G. Jansky Very Large Array, at an angular resolution of 7.2"x5.7" and a velocity resolution of 0.77 km/s. Our data reveal HI absorption towards the radio continuum of the HII region, and HI emission arising from the Orion Bar photon-dominated region (PDR) and from the Orion-KL outflow. In the Orion Bar PDR, the HI signal peaks in the same layer as the H2 near-infrared vibrational line emission, in agreement with models of the photodissociation of H2. The gas temperature in this region is approximately 540K, and the HI abundance in the interclump gas in the PDR is 5-10% of the available hydrogen nuclei. Most of the gas in this region therefore remains molecular. Mechanical feedback on the Veil manifests itself through the interaction of ionized flow systems in the Orion Nebula, in particular the Herbig-Haro object HH202, with the Veil. These interactions give rise to prominent blueward velocity shifts of the gas in the Veil. The unambi...

  10. Brackett Lines from the Super Star Cluster Nebulae in He 2-10

    CERN Document Server

    Henry, A L; Beck, S C; Crostwaite, L P; Meier, D S; Henry, Alaina L.; Turner, Jean L.; Beck, Sara C.; Crostwaite, Lucian P.; Meier, David S.

    2006-01-01

    We present high spectral resolution (v~12-16 km/s) Brackett line spectroscopy of the blue compact dwarf galaxy Henize 2-10 made with NIRSPEC on the Keck Telescope. The spatial resolution is seeing limited, at 1". We detect two distinct kinematic features separated by approximately 3", with heliocentric velocities of ~860 and ~890 km/s. In addition to a narrow core, the line profiles also display a broad, low intensity feature on the blue side of the centroid, which we attribute to an outflow. This may be a sign of aging in the clusters. We compare to archival high resolution Very Large Array (VLA) data at 1.3 cm, and find that the centimeter wavelength emission is resolved into six sources. These radio sources are organized into two larger groups, which we associate with the two kinematic peaks in the Brackett spectrum. We estimate a Lyman continuum rate of at least 7 x 10^52 s^-1, with a corresponding stellar mass of 6 x 10^6 M_sun is required to ionize the nebulae. We also estimate the size of the nebulae f...

  11. Rotation-disk connection for very low mass and substellar objects in the Orion Nebula Cluster

    CERN Document Server

    Rodriguez-Ledesma, Maria V; Eislöffel, Jochen

    2010-01-01

    Angular momentum loss requires magnetic interaction between the forming star and both the circumstellar disk and the magnetically driven outflows. In order to test these predictions many authors have investigated a rotation-disk connection in pre-main sequence objects with masses larger than about 0.4Msun. For brown dwarfs this connection was not investigated as yet because there are very few samples available. We aim to extend this investigation well down into the substellar regime for our large sample of BDs in the Orion Nebula Cluster, for which we have recently measured rotational periods. In order to investigate a rotation-disk correlation, we derived near-infrared (NIR) excesses for a sample of 732 periodic variables in the Orion Nebula Cluster with masses ranging between 1.5-0.02 Msun and whose IJHK colors are available. Circumstellar NIR excesses were derived from the Delta[I-K] index. We performed our analysis in three mass bins.We found a rotation-disk correlation in the high and intermediate mass r...

  12. Magnetospheric outflows in young stellar objects

    Directory of Open Access Journals (Sweden)

    Zanni Claudio

    2014-01-01

    Full Text Available Different classes of outflows are associated with the magnetospheric activity of accreting T Tauri protostars. Stellar winds are accelerated along the open field lines anchored in the stellar surface; disk winds (extended or X-type can be launched along the open magnetic surfaces threading the accretion disk; another type of ejection can arise from the region of interaction of the closed magnetosphere with the accretion disk (magnetospheric ejections, conical winds, where the magnetic surfaces undergo quasiperiodic episodes of inflation and reconnection. In this chapter I will present the main dynamical properties of these different types of outflow. Two main issues will be addressed. First, I will try to understand if these ejection phenomena can account for the origin of the jets often observed in young forming stellar systems. Second, I will evaluate the impact of these outflows on the angular momentum evolution of the central protostar.

  13. A submillimeter galaxy illuminating its circumgalactic medium: Ly-alpha scattering in a cold, clumpy outflow

    CERN Document Server

    Geach, J E; Alexander, D M; Blain, A W; Bremer, M; Chapin, E L; Chapman, S C; Clements, D L; Coppin, K E K; Dunlop, J S; Farrah, D; Jenness, T; Koprowski, M P; Michalowski, M J; Robson, E I; Scott, D; Smith, D J B; Spaans, M; Swinbank, A M; van der Werf, P

    2014-01-01

    We report the detection at 850um of the central source in SSA22-LAB1, the archetypal Lyman-alpha Blob (LAB), a 100kpc-scale radio-quiet emission-line nebula at z=3.1. The flux density of the source, $S_{850}=4.6\\pm1.1$mJy implies the presence of a galaxy, or group of galaxies, with a total luminosity of $L_{\\rm IR}\\approx10^{12}L_\\odot$. The position of an active source at the center of a ~50kpc-radius ring of linearly polarized Ly-alpha emission detected by Hayes et al. (2011) suggests that the central source is leaking Ly-alpha photons preferentially in the plane of the sky, which undergo scattering in HI clouds at large galactocentric radius. The Ly-alpha morphology around the submillimeter detection is reminiscent of biconical outflow, and the average Ly-alpha line profiles of the two `lobes' are dominated by a red peak, expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evi...

  14. Gas physical conditions and kinematics of the giant outflow Ou4

    CERN Document Server

    Corradi, Romano L M; Acker, Agnès; Greimel, Robert; Guillout, Patrick

    2014-01-01

    Ou4 is a recently discovered bipolar outflow with a projected size of more than one degree in the plane of the sky. It is apparently centred on the young stellar cluster -whose most massive representative is the triple system HR8119- inside the HII region Sh 2-129. The driving source, the nature, and the distance of Ou4 are not known. Deep narrow-band imagery of the whole nebula at arcsec resolution was obtained to study its morphology. Long-slit spectroscopy of the tips of the bipolar lobes was secured to determine the gas ionization mechanism, physical conditions, and line-of-sight velocities. An estimate of the proper motions at the tip of the south lobe using archival images is attempted. The existing multi-wavelength data for Sh 2-129 and HR 8119 are also comprehensively reviewed. The morphology of Ou4, its emission-line spatial distribution, line flux ratios, and the kinematic modelling adopting a bow-shock parabolic geometry, illustrate the expansion of a shock-excited fast collimated outflow. The radi...

  15. Assessing the internal consistency of the CARINA database in the Indian sector of the Southern Ocean

    Directory of Open Access Journals (Sweden)

    C. Lo Monaco

    2010-02-01

    Full Text Available Carbon and carbon-relevant hydrographic and hydrochemical ancillary data from previously not publicly available cruises were retrieved and recently merged to a new data base, CARINA (CARbon IN the Atlantic. The initial North Atlantic project, an international effort for ocean carbon synthesis, was extended to include the Arctic Mediterranean Seas (Arctic Ocean and Nordic Seas and all three sectors of the Southern Ocean. Of a total of 188 cruises, 37 cruises are part of the Southern Ocean. The present work focuses on data collected in the Indian sector (20° S–70° S; 30° E–150° E. The Southern Indian Ocean dataset covers the period 1992–2004 and includes seasonal repeated observations. Parameters including salinity, dissolved inorganic carbon (TCO2, total alkalinity (TA, oxygen, nitrate, phosphate and silicate were examined for cruise-to-cruise and overall consistency. In addition, data from an existing, quality controlled data base (GLODAP were introduced in the CARINA analysis to improve data coverage in the Southern Ocean. A global inversion was performed to synthesize the information deduced from objective comparisons of deep measurements (>1500 m at nearby stations (generally <220 km. The corrections suggested by the inversion were allowed to vary within a fixed envelope, thus accounting for ocean interior variability. The adjustments applied to CARINA data and those recommended for GLODAP data, in order to obtain a consistent merged dataset, are presented and discussed. The final outcome of this effort is a new quality controlled data base for TCO2 and other properties of the carbon system that can now be used to investigate the natural variability or stability of ocean chemistry and the accumulation of anthropogenic carbon. This data product also offers an important new synthesis of seasonal to decadal observations to validate ocean biogeochemical models in a region where available historical data were very

  16. Assessing the internal consistency of the CARINA database in the Indian sector of the Southern Ocean

    Science.gov (United States)

    Lo Monaco, C.; Álvarez, M.; Key, R. M.; Lin, X.; Tanhua, T.; Tilbrook, B.; Bakker, D. C. E.; van Heuven, S.; Hoppema, M.; Metzl, N.; Ríos, A. F.; Sabine, C. L.; Velo, A.

    2010-02-01

    Carbon and carbon-relevant hydrographic and hydrochemical ancillary data from previously not publicly available cruises were retrieved and recently merged to a new data base, CARINA (CARbon IN the Atlantic). The initial North Atlantic project, an international effort for ocean carbon synthesis, was extended to include the Arctic Mediterranean Seas (Arctic Ocean and Nordic Seas) and all three sectors of the Southern Ocean. Of a total of 188 cruises, 37 cruises are part of the Southern Ocean. The present work focuses on data collected in the Indian sector (20° S-70° S; 30° E-150° E). The Southern Indian Ocean dataset covers the period 1992-2004 and includes seasonal repeated observations. Parameters including salinity, dissolved inorganic carbon (TCO2), total alkalinity (TA), oxygen, nitrate, phosphate and silicate were examined for cruise-to-cruise and overall consistency. In addition, data from an existing, quality controlled data base (GLODAP) were introduced in the CARINA analysis to improve data coverage in the Southern Ocean. A global inversion was performed to synthesize the information deduced from objective comparisons of deep measurements (>1500 m) at nearby stations (generally accounting for ocean interior variability. The adjustments applied to CARINA data and those recommended for GLODAP data, in order to obtain a consistent merged dataset, are presented and discussed. The final outcome of this effort is a new quality controlled data base for TCO2 and other properties of the carbon system that can now be used to investigate the natural variability or stability of ocean chemistry and the accumulation of anthropogenic carbon. This data product also offers an important new synthesis of seasonal to decadal observations to validate ocean biogeochemical models in a region where available historical data were very sparse.

  17. Changes in the distance between carina and orotracheal tube during open or videolaparoscopic bariatric surgery

    Directory of Open Access Journals (Sweden)

    Giovani de Figueiredo Locks

    2015-10-01

    Full Text Available ABSTRACTOBJECTIVE: To examine whether there are changes in the distance between the orotracheal tube and carina induced by orthostatic retractor placement or by pneumoperitoneum insufflation in obese patients undergoing gastroplasty.METHODS: 60 patients undergoing bariatric surgery by two techniques: open (G1 or videolaparoscopic (G2 gastroplasty were studied. After tracheal intubation, adequate ventilation of both hemitoraxes was confirmed by lung auscultation. The distance orotracheal tube-carina was estimated with the use of a fiber bronchoscope before and after installation of orthostatic retractors in G1 or before and after insufflation of pneumoperitoneum in patients in G2.RESULTS: G1 was composed of 22 and G2 of 38 patients. No cases of endobronchial intubation were detected in either group. The mean orotracheal tube-carina distance variation was estimated in -0.03 cm (95% CI 0.06 to -0.13 in the group of patients undergoing open gastroplasty and in -0.42 cm (95% CI -0.56 to -1.4 in the group of patients undergoing videolaparoscopic gastroplasty. The extremes of variation in each group were: 0.5 cm to -1.6 cm in patients undergoing open surgery and 0.1 cm to -2.2 cm in patients undergoing videolaparoscopic surgery.CONCLUSIONS: There was no significant change in orotracheal tube-CA distance after placement of orthostatic retractors in patients undergoing open gastroplasty. There was a reduction in orotracheal tube-CA distance after insufflation of pneumoperitoneum in patients undergoing videolaparoscopic gastroplasty. We recommend attention to lung auscultation and to signals of ventilation monitoring and reevaluation of orotracheal tube placement after peritoneal insufflation.

  18. A submillimeter galaxy illuminating its circumgalactic medium: Lyα scattering in a cold, clumpy outflow

    Energy Technology Data Exchange (ETDEWEB)

    Geach, J. E.; Coppin, K. E. K.; Smith, D. J. B. [Center for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Bower, R. G.; Alexander, D. M.; Swinbank, A. M. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Bremer, M. N. [School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapin, E. L. [XMM SOC, ESAC, Apartado 78, E-28691 Villanueva de la Canada, Madrid (Spain); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University Halifax, NS B3H 3J5 (Canada); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Dunlop, J. S.; Koprowski, M. P.; Michałowski, M. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Farrah, D. [Virginia Polytechnic Institute and State University Department of Physics, MC 0435, 910 Drillfield Drive, Blacksburg, VA 24061 (United States); Jenness, T. [Joint Astronomy Centre, 660 North A' ohoku Place University Park, Hilo, HI 96720 (United States); Robson, E. I. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Scott, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Spaans, M. [Kapteyn Institute, University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands); Van der Werf, P., E-mail: j.geach@herts.ac.uk [Leiden Observatory, Leiden University, PO box 9513, 2300 RA Leiden (Netherlands)

    2014-09-20

    We report the detection at 850 μm of the central source in SSA22-LAB1, the archetypal 'Lyman-α Blob' (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S {sub 850} = 4.6 ± 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L {sub IR} ≈ 10{sup 12} L {sub ☉}. The position of an active source at the center of a ∼50 kpc radius ring of linearly polarized Lyα emission detected by Hayes et al. suggests that the central source is leaking Lyα photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Lyα morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Lyα line profiles of the two 'lobes' are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Lyα emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Lyα: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?.

  19. Protostellar Outflow Evolution in Turbulent Environments

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, A; Frank, A; Carroll, J; Blackman, E; Quillen, A

    2008-04-11

    The link between turbulence in star formatting environments and protostellar jets remains controversial. To explore issues of turbulence and fossil cavities driven by young stellar outflows we present a series of numerical simulations tracking the evolution of transient protostellar jets driven into a turbulent medium. Our simulations show both the effect of turbulence on outflow structures and, conversely, the effect of outflows on the ambient turbulence. We demonstrate how turbulence will lead to strong modifications in jet morphology. More importantly, we demonstrate that individual transient outflows have the capacity to re-energize decaying turbulence. Our simulations support a scenario in which the directed energy/momentum associated with cavities is randomized as the cavities are disrupted by dynamical instabilities seeded by the ambient turbulence. Consideration of the energy power spectra of the simulations reveals that the disruption of the cavities powers an energy cascade consistent with Burgers-type turbulence and produces a driving scale-length associated with the cavity propagation length. We conclude that fossil cavities interacting either with a turbulent medium or with other cavities have the capacity to sustain or create turbulent flows in star forming environments. In the last section we contrast our work and its conclusions with previous studies which claim that jets can not be the source of turbulence.

  20. Accretion, Outflows, and Winds of Magnetized Stars

    CERN Document Server

    Romanova, M M

    2016-01-01

    Many types of stars have strong magnetic fields that can dynamically influence the flow of circumstellar matter. In stars with accretion disks, the stellar magnetic field can truncate the inner disk and determine the paths that matter can take to flow onto the star. These paths are different in stars with different magnetospheres and periods of rotation. External field lines of the magnetosphere may inflate and produce favorable conditions for outflows from the disk-magnetosphere boundary. Outflows can be particularly strong in the propeller regime, wherein a star rotates more rapidly than the inner disk. Outflows may also form at the disk-magnetosphere boundary of slowly rotating stars, if the magnetosphere is compressed by the accreting matter. In isolated, strongly magnetized stars, the magnetic field can influence formation and/or propagation of stellar wind outflows. Winds from low-mass, solar-type stars may be either thermally or magnetically driven, while winds from massive, luminous O and B type stars...

  1. HH 223: a parsec-scale H2 outflow in the star-forming region L723

    Science.gov (United States)

    López, R.; Acosta-Pulido, J. A.; Gómez, G.; Estalella, R.; Carrasco-González, C.

    2010-11-01

    Context. The dark cloud Lynds 723 (L723) is a low-mass star-forming region where one of the few known cases of a quadrupolar CO outflow has been reported. Two recent works have found that the radio continuum source VLA 2, towards the centre of the CO outflow, is actually a multiple system of young stellar objects (YSOs). Several line-emission nebulae that lie projected on the east-west CO outflow were detected in narrow-band Hα and [S ii] images. The spectra of the knots are characteristic of shock-excited gas (Herbig-Haro spectra), with supersonic blueshifted velocities, which suggests an optical outflow also powered by the VLA 2 YSO system of L723. Aims: Our aim is to study L723 in the near-infrared and look for line-emission nebulae associated with the optical and CO outflows. Methods: We imaged a field of ~5' × 5' centred on HH 223, which includes the whole region of the quadrupolar CO outflow with narrow-band filters centred on the [Fe ii] 1.644 μm and H2 2.122 μm lines, together with off-line Hc and Kc filters. The [Fe ii] and H2 line-emission structures were identified after extracting the continuum contribution, if any. Their positions were determined from an accurate astrometry of the images. Results: The H2 line-emission structures appear distributed over a region of 5.5 arcmin (~0.5 pc for a distance of 300 pc) at both sides of the VLA 2 YSO system, with an S-shape morphology, and are projected onto the east-west CO outflow. Most of them were resolved in smaller knotty substructures. The [Fe ii] emission only appears associated with HH 223. An additional nebular emission from the continuum in Hc and Kc appears associated with HH 223-K1, the structure closest to the VLA 2 YSO system, and could be tracing the cavity walls. Conclusions: We propose that the H2 structures form part of a large-scale near-infrared outflow, which is also associated with the VLA 2 YSO system. The current data do not allow us to discern which of the YSOs of VLA 2 is powering

  2. Discovery of an Enormous Lyα Nebula in a Massive Galaxy Overdensity at z = 2.3

    Science.gov (United States)

    Cai, Zheng; Fan, Xiaohui; Yang, Yujin; Bian, Fuyan; Prochaska, J. Xavier; Zabludoff, Ann; McGreer, Ian; Zheng, Zhen-Ya; Green, Richard; Cantalupo, Sebastiano; Frye, Brenda; Hamden, Erika; Jiang, Linhua; Kashikawa, Nobunari; Wang, Ran

    2017-03-01

    Enormous Lyα nebulae (ELANe), unique tracers of galaxy density peaks, are predicted to lie at the nodes and intersections of cosmic filamentary structures. Previous successful searches for ELANe have focused on wide-field narrowband surveys or have targeted known sources such as ultraluminous quasi-stellar objects (QSOs) or radio galaxies. Utilizing groups of coherently strong Lyα absorptions, we have developed a new method to identify high-redshift galaxy overdensities and have identified an extremely massive overdensity, BOSS1441, at z=2{--}3. In its density peak, we discover an ELAN that is associated with a relatively faint continuum. To date, this object has the highest diffuse Lyα nebular luminosity of {L}{nebula}=5.1+/- 0.1× {10}44 erg s‑1. Above the 2σ surface brightness limit of SB{}{Lyα }=4.8× {10}-18 erg s‑1 cm‑2 arcsec‑2, this nebula has an end-to-end spatial extent of 442 kpc. This radio-quiet source also has extended C iv λ 1549 and He ii λ 1640 emission on ≳ 30 {kpc} scales. Note that the Lyα, He ii, and C iv emissions all have double-peaked line profiles. Each velocity component has an FWHM of ≈700–1000 km s‑1. We argue that this Lyα nebula could be powered by shocks due to an active galactic nucleus–driven outflow or photoionization by a strongly obscured source.

  3. The Resolved Outflow from 3C 48

    Science.gov (United States)

    Shih, Hsin-Yi; Stockton, Alan

    2014-10-01

    We investigate the properties of the high-velocity outflow driven by the young radio jet of 3C 48, a compact-steep-spectrum source. We use the Space Telescope Imaging Spectrograph on board the Hubble Space Telecope to obtain (1) low-resolution UV and optical spectra and (2) multi-slit medium-resolution spectra of the ionized outflow. With supporting data from ground-based spectrographs, we are able to accurately measure the ratios of diagnostic emission lines such as [O III] λ5007, [O III] λ3727, [N II] λ6548, Hα, Hβ, [Ne V] λ3425, and [Ne III] λ3869. We fit the observed emission-line ratios using a range of ionization models, powered by active galactic nucleus (AGN) radiation and shocks, produced by the MAPPINGS code. We have determined that AGN radiation is likely the dominant ionization source. The outflow's density is estimated to be in the range n = 103-104 cm-3, the mass is ~6 × 106 M ⊙, and the metallicity is likely equal to or higher than solar. Compared with the typical outflows associated with more evolved radio jets, this young outflow is denser, less massive, and more metal rich. Multi-slit observations allow us to construct a two-dimensional velocity map of the outflow that shows a wide range of velocities with distinct velocity components, suggesting a wide-angle clumpy outflow. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program GO-11574. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Some of the

  4. Star Formation in the Eagle Nebula

    CERN Document Server

    Oliveira, Joana M

    2008-01-01

    M16 (the Eagle Nebula) is a striking star forming region, with a complex morphology of gas and dust sculpted by the massive stars in NGC 6611. Detailed studies of the famous ``elephant trunks'' dramatically increased our understanding of the massive star feedback into the parent molecular cloud. A rich young stellar population (2 - 3 Myr) has been identified, from massive O-stars down to substellar masses. Deep into the remnant molecular material, embedded protostars, Herbig-Haro objects and maser sources bear evidence of ongoing star formation in the nebula, possibly triggered by the massive cluster members. M 16 is a excellent template for the study of star formation under the hostile environment created by massive O-stars. This review aims at providing an observational overview not only of the young stellar population but also of the gas remnant of the star formation process.

  5. The nebulae around LBVs: a multiwavelength approach

    CERN Document Server

    Umana, Grazia; Trigilio, Corrado; Leto, Paolo; Hora, Joseph L; Fazio, Giovanni

    2010-01-01

    We present first results of our study of a sample of Galactic LBV, aimed to contribute to a better understanding of the LBV phenomenon, by recovering the mass-loss history of the central object from the analysis of its associated nebula. Mass-loss properties have been derived by a synergistic use of different techniques, at different wavelengths, to obtain high-resolution, multi-wavelength maps, tracing the different emitting components coexisting in the stellar ejecta: the ionized/neutral gas and the dust. Evidence for asymmetric mass-loss and observational evidence of possible mutual interaction between gas and dust components have been observed by the comparison of mid-IR (Spitzer/IRAC, VLT/VISIR) and radio (VLA) images of the nebulae, while important information on the gas and dust composition have been derived from Spitzer/IRS spectra.

  6. Ring Nebulae: Tracers of the CNO Nucleosynthesis

    CERN Document Server

    Mesa-Delgado, A; García-Rojas, J

    2015-01-01

    Preliminary results are presented from spectroscopic data in the optical range of the Galactic ring nebulae NGC 6888, G2:4+1:4, RCW 58 and Sh2-308. Deep observations with long exposure times were carried out at the 6.5m Clay Telescope and at the 10.4m Gran Telescopio Canarias. In NGC 6888, recombination lines of C II, O II and N II are detected with signal-to-noise ratios higher than 8. The chemical content of NGC 6888 is discussed within the chemical enrichment predicted by evolution models of massive stars. For all nebulae, a forthcoming work will content in-depth details about observations, analysis and final results (Esteban et al. 2015, in prep.).

  7. Magnetic field in the primitive solar nebula

    Science.gov (United States)

    Levy, E. H.

    1978-01-01

    Carbonaceous chondrites have apparently been magnetized in their early history in magnetic fields with intensities of 0.1 to 10 G, but the origin of the magnetizing field has remained obscured. It is suggested that the magnetic field recorded in the remanence of carbonaceous chondrites may have been produced by a self-excited hydromagnetic dynamo in the gaseous preplanetary nebula from which the solar system is thought to have formed. Recently computed models for the evolution of the preplanetary nebula, consisting of turbulent and differentially rotating gaseous disks with characteristic radial scales of several AU, are used to demonstrate the feasibility of this hypothesis. The maximum field intensity that might be realized by the dynamo production process is estimated to be as high as 1 to 10 G, taking into account two dynamical mechanisms that limit the strength of the field (the Coriolis force and ambipolar diffusion).

  8. Interstellar molecules - Formation in solar nebulae

    Science.gov (United States)

    Anders, E.

    1973-01-01

    Herbig's (1970) hypothesis that solar nebulae might be the principal source of interstellar grains and molecules is investigated. The investigation includes the determination of physical and chemical conditions in the early solar system. The production of organic compounds in the solar nebula is studied, and the compounds in meteorites are compared with those obtained in Miller-Urey and Fischer-Tropsch-type (FTT) reactions, taking into consideration aliphatic hydrocarbons, aromatic hydrocarbons, purines, pyrimidines, amino acids, porphyrins, and aspects of carbon-isotope fractionation. It is found that FTT reactions account reasonably well for all well-established features of organic matter in meteorites investigated. The distribution of compounds produced by FTT reactions is compared with the distribution of interstellar molecules. Biological implications of the results are considered.

  9. FACT. Energy spectrum of the Crab Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Temme, Fabian; Einecke, Sabrina; Buss, Jens [TU Dortmund, Experimental Physics 5, Otto-Hahn-Str.4, 44221 Dortmund (Germany); Collaboration: FACT-Collaboration

    2016-07-01

    The First G-APD Cherenkov Telescope is the first Imaging Air Cherenkov Telescope which uses silicon photon detectors (G-APDs aka SiPM) as photo sensors. With more than four years of operation, FACT proved an application of SiPMs is suitable for the field of ground-based gamma-ray astronomy. Due to the stable flux at TeV energies, the Crab Nebula is handled as a ''standard candle'' in Cherenkov astronomy. The analysis of its energy spectrum and comparison with other experiments, allows to evaluate the performance of FACT. A modern analysis chain, based on data stream handling and multivariate analysis methods was developed in close cooperation with the department of computer science at the TU Dortmund. In this talk, this analysis chain and its application are presented. Further to this, results, including the energy spectrum of the Crab Nebula, measured with FACT, are shown.

  10. The theory of pulsar winds and nebulae

    CERN Document Server

    Kirk, J G; Petri, J

    2007-01-01

    We review current theoretical ideas on pulsar winds and their surrounding nebulae. Relativistic MHD models of the wind of the aligned rotator, and of the striped wind, together with models of magnetic dissipation are discussed. It is shown that the observational signature of this dissipation is likely to be point-like, rather than extended, and that pulsed emission may be produced. The possible pulse shapes and polarisation properties are described. Particle acceleration at the termination shock of the wind is discussed, and it is argued that two distinct mechanisms must be operating, with the first-order Fermi mechanism producing the high-energy electrons (above 1 TeV) and either magnetic annihilation or resonant absorption of ion cyclotron waves responsible for the 100 MeV to 1 TeV electrons. Finally, MHD models of the morphology of the nebula are discussed and compared with observation.

  11. Discovery of New Faint Northern Galactic Planetary Nebulae

    CERN Document Server

    Acker, Agnes; Outters, Nicolas; Miszalski, Brent; Sabin, Laurence; Le Du, Pascal; Alves, Filipe

    2012-01-01

    We present the discovery of 6 nebular objects made by amateur astronomers. Four of these discoveries are clearly planetary nebulae (PNe), one is a possible PN, and another is a likely H II region. The bipolar nebula Ou4 presents the largest angular extent ever found : over one degree on the sky! We consider various scenarios that could explain such a nebula. Ou4 could be one of the nearest PNe known, though its possible PN nature will need confirmation.

  12. The Implications of Extreme Outflows from Extreme Starbursts

    OpenAIRE

    Heckman, Timothy M.; Borthakur, Sanchayeeta

    2016-01-01

    Interstellar ultraviolet absorption-lines provide crucial information about the properties of galactic outflows. In this paper, we augment our previous analysis of the systematic properties of starburst-driven galactic outflows by expanding our sample to include a rare population of starbursts with exceptionally high outflow velocities. In principle, these could be a qualitatively different phenomenon from more typical outflows. However, we find that instead these starbursts lie on, or along ...

  13. Planetary nebulae in the Small Magellanic Cloud

    Science.gov (United States)

    Ventura, P.; Stanghellini, L.; Di Criscienzo, M.; García-Hernández, D. A.; Dell'Agli, F.

    2016-08-01

    We analyse the planetary nebulae (PNe) population of the Small Magellanic Cloud (SMC), based on evolutionary models of stars with metallicities in the range 10-3 ≤ Z ≤ 4 × 10-3 and mass 0.9 M⊙ Magellanic Cloud is explained on the basis of the diverse star formation history and age-metallicity relation of the two galaxies. The implications of this study for some still highly debated points regarding the AGB evolution are also commented.

  14. Multiband observations of the Crab Nebula

    Science.gov (United States)

    Krassilchtchikov, A. M.; Bykov, A. M.; Castelletti, G. M.; Dubner, G. M.; Kargaltsev, O. Yu; Pavlov, G. G.

    2017-01-01

    Results of simultaneous imaging of the Crab Nebula in the radio (JVLA), optical (HST), and X-ray (Chandra) bands are presented. The images show a variety of small-scale structures, including wisps mainly located to the north-west of the pulsar and knots forming a ring-like structure associated with the termination shock of the pulsar wind. The locations of the structures in different bands do not coincide with each other.

  15. Pulsating Radio Sources near the Crab Nebula.

    Science.gov (United States)

    Staelin, D H; Reifenstein, E C

    1968-12-27

    Two new pulsating radio sources, designated NP 0527 and NP 0532, were found near the Crab Nebula and could be coincident with it. Both sources are sporadic, and no periodicities are evident. The pulse dispersions indicate that 1.58 +/- 0.03 and 1.74 +/- 0.02 x 10(20) electrons per square centimeter lie in the direction of NP 0527 and NP 0532, respectively.

  16. High scale anisotropies in planetary nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Pascoli, G.

    1986-06-01

    We present a new classification of Planetary Nebulae (PN) grounded on their characteristic symmetries: bipolarity, ring shape, spiral structure, etc... The different anisotropic models (rotation of nucleus, binary progenitor intranebular magnetic field, nebular rotation, etc...) which have been lately proposed, are analysed and their explanatory power is tested with certain morphological criterious. The comparison with the other classifications (Acker, 1980; Kaler, 1978; Peimbert, 1978) reveals that the morphology has been insufficiently discussed in these latters.

  17. of Planetary Nebulae III. NGC 6781

    Directory of Open Access Journals (Sweden)

    Hugo E. Schwarz

    2006-01-01

    Full Text Available Continuing our series of papers on the three-dimensional (3D structures and accurate distances to Planetary Nebulae (PNe, we present our study of the planetary nebula NGC6781. For this object we construct a 3D photoionization model and, using the constraints provided by observational data from the literature we determine the detailed 3D structure of the nebula, the physical parameters of the ionizing source and the first precise distance. The procedure consists in simultaneously fitting all the observed emission line morphologies, integrated intensities and the two-dimensional (2D density map from the [SII] (sulfur II line ratios to the parameters generated by the model, and in an iterative way obtain the best fit for the central star parameters and the distance to NGC6781, obtaining values of 950±143 pc (parsec – astronomic distance unit and 385 LΘ (solar luminosity for the distance and luminosity of the central star respectively. Using theoretical evolutionary tracks of intermediate and low mass stars, we derive the mass of the central star of NGC6781 and its progenitor to be 0.60±0.03MΘ (solar mass and 1.5±0.5MΘ respectively.

  18. Dusty globules in the Crab Nebula

    CERN Document Server

    Grenman, Tiia; Elfgren, Erik

    2016-01-01

    From existing broad-band images obtained with the Hubble Space Telescope, we located 92 globules, for which we derived positions, dimensions, orientations, extinctions, masses, proper motions, and their distributions. The globules have mean radii ranging from 400 to 2000 AU and are not resolved in current infrared images of the nebula. The extinction law for dust grains in these globules matches a normal interstellar extinction law. Derived masses of dust range from 1 to 60 x 10^(-6) solar masses, and the total mass contained in globules constitute a fraction of approximately 2% or less of the total dust content of the nebula. The globules are spread over the outer part of the nebula, and a fraction of them coincide in position with emission filaments, where we find elongated globules that are aligned with these filaments. Only 10% of the globules are coincident in position with the numerous H2-emitting knots found in previous studies. All globules move outwards from the centre with transversal velocities of ...

  19. New portrait of Omega Nebula's glistening watercolours

    Science.gov (United States)

    2009-07-01

    The Omega Nebula, sometimes called the Swan Nebula, is a dazzling stellar nursery located about 5500 light-years away towards the constellation of Sagittarius (the Archer). An active star-forming region of gas and dust about 15 light-years across, the nebula has recently spawned a cluster of massive, hot stars. The intense light and strong winds from these hulking infants have carved remarkable filigree structures in the gas and dust. When seen through a small telescope the nebula has a shape that reminds some observers of the final letter of the Greek alphabet, omega, while others see a swan with its distinctive long, curved neck. Yet other nicknames for this evocative cosmic landmark include the Horseshoe and the Lobster Nebula. Swiss astronomer Jean-Philippe Loys de Chéseaux discovered the nebula around 1745. The French comet hunter Charles Messier independently rediscovered it about twenty years later and included it as number 17 in his famous catalogue. In a small telescope, the Omega Nebula appears as an enigmatic ghostly bar of light set against the star fields of the Milky Way. Early observers were unsure whether this curiosity was really a cloud of gas or a remote cluster of stars too faint to be resolved. In 1866, William Huggins settled the debate when he confirmed the Omega Nebula to be a cloud of glowing gas, through the use of a new instrument, the astronomical spectrograph. In recent years, astronomers have discovered that the Omega Nebula is one of the youngest and most massive star-forming regions in the Milky Way. Active star-birth started a few million years ago and continues through today. The brightly shining gas shown in this picture is just a blister erupting from the side of a much larger dark cloud of molecular gas. The dust that is so prominent in this picture comes from the remains of massive hot stars that have ended their brief lives and ejected material back into space, as well as the cosmic detritus from which future suns form. The

  20. The evolution of planetary nebulae VII. Modelling planetary nebulae of distant stellar systems

    CERN Document Server

    Schönberner, D; Sandin, C; Steffen, M

    2010-01-01

    By means of hydrodynamical models we do the first investigations of how the properties of planetary nebulae are affected by their metal content and what can be learned from spatially unresolved spectrograms of planetary nebulae in distant stellar systems. We computed a new series of 1D radiation-hydrodynamics planetary nebulae model sequences with central stars of 0.595 M_sun surrounded by initial envelope structures that differ only by their metal content. At selected phases along the evolutionary path, the hydrodynamic terms were switched off, allowing the models to relax for fixed radial structure and radiation field into their equilibrium state with respect to energy and ionisation. The analyses of the line spectra emitted from both the dynamical and static models enabled us to systematically study the influence of hydrodynamics as a function of metallicity and evolution. We also recomputed selected sequences already used in previous publications, but now with different metal abundances. These sequences w...

  1. A deep kinematic survey of planetary nebulae in the Andromeda Galaxy using the Planetary Nebula Spectrograph

    CERN Document Server

    Merrett, H R; Bridges, T J; Capaccioli, M; Carter, D; Coccato, L; Douglas, N G; Evans, N W; Freeman, K C; Gerhard, O; Halliday, C; Kuijken, K; Merrifield, M R; Napolitano, N R; Romanowsky, A J; Wilkinson, M I

    2006-01-01

    We present a catalogue of positions, magnitudes and velocities for 3300 emission-line objects found by the Planetary Nebula Spectrograph in a survey of the Andromeda Galaxy, M31. Of these objects, 2615 are found likely to be planetary nebulae (PNe) associated with M31. The survey area covers the whole of M31's disk out to a radius of 1.5 degrees. Beyond this radius, observations have been made along the major and minor axes, and the Northern Spur and Southern Stream regions. The calibrated data have been checked for internal consistency and compared with other catalogues. With the exception of the very central, high surface brightness region of M31, this survey is complete to a magnitude limit of m_5007~23.75, 3.5 magnitudes into the planetary nebula luminosity function.

  2. A gigantic X-ray flare from the star Trumpler 14 Y442 in the Carina star forming complex

    Science.gov (United States)

    Hamaguchi, Kenji; Drake, Stephen A.; Corcoran, Michael F.; Richardson, Noel; Teodoro, Mairan

    2015-09-01

    XMM-Newton, NuSTAR and Swift observations of the Carina star forming complex on 2015 July 16 (ObsID - XMM:0762910401, NuSTAR:30101005002, Swift:00081578001) detected an X-ray flare at the coordinates (R.A., Dec)[J2000] = (10 44 02.80, -59 39 46.7).

  3. VizieR Online Data Catalog: UBVI CCD photometry of Carina region stars (Molina-Lera+, 2016)

    Science.gov (United States)

    Molina-Lera, J. A.; Baume, G.; Gamen, R.; Costa, E.; Carraro, G.

    2016-08-01

    Photometric parameters for 62730 stars in the carina region covering 6 stellar clusters (NGC 3752, Trumpler 18, NGC 3590, Hogg 10, 11 and 12) and the surrounding field. The photometry was secured in March 2006 and March 2009 with the Y4KCAM camera attached to the Cerro Tololo Inter American Observatory (CTIO, Chile) 1.0-m telescope. (1 data file).

  4. Discovery of VHE emission towards the Carina arm region with the H.E.S.S. telescope array: HESS J1018-589

    Science.gov (United States)

    H. E. S. S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Becherini, Y.; Becker, J.; Bernlöh, K.; Birsin, E.; Biteau, J.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Cologna, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gallant, Y. A.; Gast, H.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Göring, D.; Häffner, S.; Hague, J. D.; Hahn, J.; Hampf, D.; Harris, J.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Khélifi, B.; Klochkov, D.; Klużniak, D.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Krayzel, F.; Laffon, H.; Lamanna, G.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Mohamed, M.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Perez, J.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Rayner, S. M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sheidaei, F.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.

    2012-05-01

    The Carina arm region, containing the supernova remnant SNR G284.3-1.8, the high-energy (HE; E > 100 MeV) binary 1FGL J1018.6-5856 and the energetic pulsar PSR J1016-5857 and its nebula, has been observed with the H.E.S.S. telescope array. The observational coverage of the region in very-high-energy (VHE; E > 0.1 TeV) γ-rays benefits from deep exposure (40 h) of the neighboring open cluster Westerlund 2. The observations have revealed a new extended region of VHE γ-ray emission. The new VHE source HESS J1018-589 shows a bright, point-like emission region positionally coincident with SNR G284.3-1.8 and 1FGL J1018.6-5856 and a diffuse extension towards the direction of PSR J1016-5857. A soft (Γ = 2.7 ± 0.5stat)photon index, with a differential flux at 1 TeV of N0 = (4.2 ± 1.1) × 10-13 TeV-1 cm-2 s-1 is found for the point-like source, whereas the total emission region including the diffuse emission region is well fit by a power-law function with spectral index Γ = 2.9 ± 0.4stat and differential flux at 1 TeV of N0 = (6.8 ± 1.6) × 10-13 TeV-1 cm-2 s-1. This H.E.S.S. detection motivated follow-up X-ray observations with the XMM-Newton satellite to investigate the origin of the VHE emission. The analysis of the XMM-Newton data resulted in the discovery of a bright, non-thermal point-like source (XMMU J101855.4-58564) with a photon index of Γ = 1.65 ± 0.08 in the center of SNR G284.3-1.8, and a thermal, extended emission region coincident with its bright northern filament. The characteristics of this thermal emission are used to estimate the plasma density in the region as n ≈ 0.5 cm-3 (2.9 kpc/d)2. The position of XMMU J101855.4-58564 is compatible with the position reported by the Fermi-LAT collaboration for the binary system 1FGL J1018.6-5856 and the variable Swift XRT source identified with it. The new X-ray data are used alongside archival multi-wavelength data to investigate the relationship between the VHE γ-ray emission from HESS J1018-589 and the

  5. Morphological and kinematic signatures of a binary central star in the planetary nebula Hu 2-1

    CERN Document Server

    Miranda, L F; Guerrero, M; Vázquez, R A; Gómez, Y; Miranda, Luis F.; Torrelles, Jose M.; Guerrero, Martin A.; Vazquez, Roberto; Gomez, Yolanda

    2000-01-01

    We present narrow-band optical images, VLA-A 3.6 cm continuum and H92alpha emission line data and high resolution long-slit [N II] spectra of Hu 2-1. The formation of Hu 2-1 appears dominated by anisotropic mass ejection during the late AGB stage of its progenitor and by variable, ``precessing'' collimated bipolar outflows during the proto-PN and/or early PN phases. The data strongly support the existence of a binary central star at center of Hu 2-1: (1) the brightness distribution of the bipolar lobes and inner shell is point-symmetric, and the bipolar lobes show departures from axial symmetry; (2) the position of the central star is off-center; (3) mass ejection towards the equatorial plane is detected; (4) ``precessing'' collimated outflows are present. Besides all this circumstantial evidences, the analysis of the kinematics shows that the systemic velocity of the bipolar outflows does not coincide with the systemic velocity of the nebula. We propose that this velocity difference is a direct evidence of o...

  6. Eclipse and Collapse of the Colliding Wind X-ray Emission from Eta Carinae

    Science.gov (United States)

    Hamaguchi, Kenji; Corcoran, Michael F.

    2012-01-01

    X-ray emission from the massive stellar binary system, Eta Carinae, drops strongly around periastron passage; the event is called the X-ray minimum. We launched a focused observing campaign in early 2009 to understand the mechanism of causing the X-ray minimum. During the campaign, hard X-ray emission (<10 keV) from Eta Carinae declined as in the previous minimum, though it recovered a month earlier. Extremely hard X-ray emission between 15-25 keV, closely monitored for the first time with the Suzaku HXD/PIN, decreased similarly to the hard X-rays, but it reached minimum only after hard X-ray emission from the star had already began to recover. This indicates that the X-ray minimum is produced by two composite mechanisms: the thick primary wind first obscured the hard, 2-10 keV thermal X-ray emission from the wind-wind collision (WWC) plasma; the WWC activity then decays as the two stars reach periastron.

  7. VLT/FLAMES spectroscopy of Red Giant Branch stars in the Carina dwarf spheroidal galaxy

    CERN Document Server

    Lemasle, B; Tolstoy, E; Venn, K A; Shetrone, M D; Irwin, M J; de Boer, T J L; Starkenburg, E; Salvadori, S

    2011-01-01

    The ages of individual Red Giant Branch stars (RGB) can range from 1 Gyr old to the age of the Universe, and it is believed that the abundances of most chemical elements in their photospheres remain unchanged with time (those that are not affected by the 1st dredge-up). This means that they trace the ISM in the galaxy at the time the star formed, and hence the chemical enrichment history of the galaxy. CMD analysis has shown the Carina dwarf spheroidal (dSph) to have had an unusually episodic star formation history (SFH) which is expected to be reflected in the abundances of different chemical elements. We use the VLT-FLAMES spectrograph in HR mode (R~20000) to measure the abundances of several chemical elements in a sample of 35 RGB stars in Carina. We also combine these abundances with photometry to derive age estimates for these stars. This allows us to determine which of two distinct star formation (SF) episodes the stars in our sample belong to, and thus to define the relationship between SF and chemical...

  8. 3D printing meets computational astrophysics: deciphering the structure of η Carinae's inner colliding winds

    Science.gov (United States)

    Madura, T. I.; Clementel, N.; Gull, T. R.; Kruip, C. J. H.; Paardekooper, J.-P.

    2015-06-01

    We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (≳120 M⊙), highly eccentric (e ˜ 0.9) binary star system η Carinae. We demonstrate the methodology used to incorporate 3D interactive figures into a PDF (Portable Document Format) journal publication and the benefits of using 3D visualization and 3D printing as tools to analyse data from multidimensional numerical simulations. Using a consumer-grade 3D printer (MakerBot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics simulations of η Carinae's inner (r ˜ 110 au) wind-wind collision interface at multiple orbital phases. The 3D prints and visualizations reveal important, previously unknown `finger-like' structures at orbital phases shortly after periastron (φ ˜ 1.045) that protrude radially outwards from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. thin-shell, Rayleigh-Taylor) that arise at the interface between the radiatively cooled layer of dense post-shock primary-star wind and the fast (3000 km s-1), adiabatic post-shock companion-star wind. The success of our work and easy identification of previously unrecognized physical features highlight the important role 3D printing and interactive graphics can play in the visualization and understanding of complex 3D time-dependent numerical simulations of astrophysical phenomena.

  9. He II 4686 in eta Carinae and the nature of the 5.538-yr cycle

    CERN Document Server

    Teodoro, M; Arias, J I; de Araújo, F X; Barbá, R H; Corcoran, M F; Fernandes, M Borges; Fernández-Lajús, E; Fraga, L; Gamen, R C; González, J F; Groh, J H; Marshall, J L; McGregor, P J; Morrell, N; Nicholls, D C; Parkin, E R; Pereira, C B; Phillips, M M; Solivella, G R; Steiner, J E; Stritzinger, M; Thompson, I; Torres, C A O; Torres, M A P; Zevallos-Herencia, M I

    2011-01-01

    The periodic minima in eta Carinae are now well defined and interpreted as due to periastron passage of two massive stars in a very eccentric orbit. Different mechanisms have been proposed to explain the light curve of different spectral features, such as eclipse, shell ejection, accretion and/or collapse of the primary wind onto the secondary star. All of them face difficulties to explain the observations in the full range of wavelengths. To better understand the nature of cyclic events, we performed a dense monitoring of eta Carinae along the 2009 spectroscopic event, focusing on the high-energy He II 4686 emission line. Our results indicate that the intensity curve of He II 4686 peaks at L~310 L_sun, has a phase-locked behaviour and shows a temporal correlation with the X-ray emission, ruling out many proposed sources of energy. The most suitable location for the He II 4686 emission region is the shocked primary wind, about 4-5 AU downstream from the apex. The 'collapse' component seen in light curves of X...

  10. The Carina Project. X. On the kinematics of old and intermediate-age stellar populations

    CERN Document Server

    Fabrizio, M; Nonino, M; Lokas, E L; Ferraro, I; Iannicola, G; Buonanno, R; Cassisi, S; Coppola, G; Dall'Ora, M; Gilmozzi, R; Marconi, M; Monelli, M; Romaniello, M; Stetson, P B; Thévenin, F; Walker, A R

    2016-01-01

    We present new radial velocity (RV) measurements of old (horizontal branch) and intermediate-age (red clump) stellar tracers in the Carina dwarf spheroidal. They are based on more than 2,200 low-resolution spectra collected with VIMOS at VLT. The targets are faint (20Carina stars. We found that the intermediate-age stellar component shows a well defined rotational pattern around the minor axis. The western and the eastern side of the galaxy differ by +5 and -4 km s-1 when compared with the main RV peak. The old stellar component is characterized by a larger RV dispersion and does not show evidence of RV pattern. We compared the observed RV distribution with N-body simulations for a former disky dwarf galaxy orbit...

  11. The UV Scattering Halo of the Central Source Associated with Eta Carinae

    CERN Document Server

    Hillier, D J; Damineli, A; Gull, T R; Hamann, F W; Iping, R; Martin, J C; Nielsen, K; Smith, N; Sonneborn, G; Weis, K; Smith, Nathan

    2006-01-01

    We have made an extensive study of the UV spectrum of Eta Carinae, and find that we do not directly observe the star and its wind in the UV. Because of dust along our line of sight, the UV light that we observe arises from bound-bound scattering at large impact parameters. We obtain a reasonable fit to the UV spectrum by using only the flux that originates outside 0.033". This explains why we can still observe the primary star in the UV despite the large optical extinction -- it is due to the presence of an intrinsic coronagraph in the Eta Carinae system, and to the extension of the UV emitting region. It is not due to peculiar dust properties alone. We have computed the spectrum of the purported companion star, and show that it could only be directly detected in the UV spectrum preferentially in the Far Ultraviolet Spectroscopic Explorer (FUSE) spectral region (912-1175 Ang.). However, we find no direct evidence for a companion star, with the properties indicated by X-ray studies and studies of the Weigelt b...

  12. X-ray Spectral Variation of Eta Carinae through the 2003 X-ray Minimum

    CERN Document Server

    Hamaguchi, K; Gull, T; Ishibashi, K; Pittard, J M; Hillier, D J; Damineli, A; Davidson, K; Nielsen, K E; Kober, G V; Hamaguchi, Kenji; Corcoran, Michael F.; Gull, Theodore; Ishibashi, Kazunori; Pittard, Julian M.; Damineli, Augusto; Davidson, Kris; Nielsen, Krister E.; Kober, Gladys Vieira

    2007-01-01

    We report the results of an X-ray observing campaign on the massive, evolved star Eta Carinae, concentrating on the 2003 X-ray minimum as seen by the XMM-Newton observatory. These are the first spatially-resolved X-ray monitoring observations of the stellar X-ray spectrum during the minimum. The hard X-ray emission, believed to be associated with the collision of Eta Carinae's wind with the wind from a massive companion star, varied strongly in flux on timescales of days, but not significantly on timescales of hours. The lowest X-ray flux in the 2-10 keV band seen by XMM-Newton was only 0.7% of the maximum seen by RXTE just before the X-ray minimum. The slope of the X-ray continuum above 5 keV did not vary in any observation, which suggests that the electron temperature of the hottest plasma associated with the stellar source did not vary significantly at any phase. Through the minimum, the absorption to the stellar source increased by a factor of 5-10 to NH ~3-4E23 cm-2. The thermal Fe XXV emission line show...

  13. 3D Printing Meets Computational Astrophysics: Deciphering the Structure of Eta Carinae's Inner Colliding Winds

    CERN Document Server

    Madura, Thomas I; Gull, Theodore R; Kruip, Chael J H; Paardekooper, Jan-Pieter

    2015-01-01

    We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (>120 M_Sun), highly eccentric (e ~ 0.9) binary star system Eta Carinae. We demonstrate the methodology used to incorporate 3D interactive figures into a PDF journal publication and the benefits of using 3D visualization and 3D printing as tools to analyze data from multidimensional numerical simulations. Using a consumer-grade 3D printer (MakerBot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics (SPH) simulations of Eta Carinae's inner (r ~ 110 au) wind-wind collision interface at multiple orbital phases. The 3D prints and visualizations reveal important, previously unknown 'finger-like' structures at orbital phases shortly after periastron (phi ~ 1.045) that protrude radially outward from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. thin-shell, Rayleigh-Taylor) that arise a...

  14. SECULAR CHANGES IN ETA CARINAE'S WIND 1998-2011

    Energy Technology Data Exchange (ETDEWEB)

    Mehner, Andrea [ESO, Alonso de Cordova 3107, Vitacura, Santiago de Chile (Chile); Davidson, Kris; Humphreys, Roberta M. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Ishibashi, Kazunori [Global COE, Division of Particle Physics and Astrophysics, Nagoya University, Nagoya 464-8602 (Japan); Martin, John C. [Department of Physics and Astronomy, University of Illinois Springfield, Springfield, IL 62703 (United States); Ruiz, Maria Teresa [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago de Chile (Chile); Walter, Frederick M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2012-05-20

    Stellar wind-emission features in the spectrum of eta Carinae have decreased by factors of 1.5-3 relative to the continuum within the last 10 years. We investigate a large data set from several instruments (STIS, GMOS, UVES) obtained between 1998 and 2011 and analyze the progression of spectral changes in direct view of the star, in the reflected polar-on spectra at FOS4, and at the Weigelt knots. We find that the spectral changes occurred gradually on a timescale of about 10 years and that they are dependent on the viewing angle. The line strengths declined most in our direct view of the star. About a decade ago, broad stellar wind-emission features were much stronger in our line-of-sight view of the star than at FOS4. After the 2009 event, the wind-emission line strengths are now very similar at both locations. High-excitation He I and N II absorption lines in direct view of the star strengthened gradually. The terminal velocity of Balmer P Cyg absorption lines now appears to be less latitude dependent, and the absorption strength may have weakened at FOS4. Latitude-dependent alterations in the mass-loss rate and the ionization structure of eta Carinae's wind are likely explanations for the observed spectral changes.

  15. Hierarchies of Models: Toward Understanding Planetary Nebulae

    Science.gov (United States)

    Knuth, Kevin H.; Hajian, Arsen R.; Clancy, Daniel (Technical Monitor)

    2003-01-01

    Stars like our sun (initial masses between 0.8 to 8 solar masses) end their lives as swollen red giants surrounded by cool extended atmospheres. The nuclear reactions in their cores create carbon, nitrogen and oxygen, which are transported by convection to the outer envelope of the stellar atmosphere. As the star finally collapses to become a white dwarf, this envelope is expelled from the star to form a planetary nebula (PN) rich in organic molecules. The physics, dynamics, and chemistry of these nebulae are poorly understood and have implications not only for our understanding of the stellar life cycle but also for organic astrochemistry and the creation of prebiotic molecules in interstellar space. We are working toward generating three-dimensional models of planetary nebulae (PNe), which include the size, orientation, shape, expansion rate and mass distribution of the nebula. Such a reconstruction of a PN is a challenging problem for several reasons. First, the data consist of images obtained over time from the Hubble Space Telescope (HST) and spectra obtained from Kitt Peak National Observatory (KPNO) and Cerro Tololo Inter-American Observatory (CTIO). These images are of course taken from a single viewpoint in space, which amounts to a very challenging tomographic reconstruction. Second, the fact that we have two disparate and orthogonal data types requires that we utilize a method that allows these data to be used together to obtain a solution. To address these first two challenges we employ Bayesian model estimation using a parameterized physical model that incorporates much prior information about the known physics of the PN. In our previous works we have found that the forward problem of the comprehensive model is extremely time consuming. To address this challenge, we explore the use of a set of hierarchical models, which allow us to estimate increasingly more detailed sets of model parameters. These hierarchical models of increasing complexity are akin

  16. Influence of Mediterranean Outflow on climate

    Science.gov (United States)

    Rahmstorf, Stefan

    A cover article in Eos last year [Johnson, 1997] called for a dam across the Strait of Gibraltar to prevent a new Ice Age. In this article, R. G. Johnson argued that reduced Nile River flow after building the Aswan Dam increases Mediterranean Sea salinity, leading to enhanced outflow of salty water into the Atlantic Ocean. This, in turn, would alter the thermohaline (that is, temperature and salinity driven) circulation of the Atlantic, heat up the Labrador Sea and enhance evaporation there, and increase snowfall in Canada until a new ice sheet builds up. Ocean circulation model experiments, however, suggest that this fear is unfounded. While Mediterranean saltwater outflow (Figure 1a) does appear to have some effect on North Atlantic circulation and surface climate, the change in Mediterranean salt budget resulting from the Aswan Dam is far too small to have any noticeable impact.

  17. Protostellar outflows with Smoothed Particle Magnetohydrodynamics (SPMHD)

    CERN Document Server

    Bürzle, Florian; Stasyszyn, Federico; Dolag, Klaus; Klessen, Ralf S

    2011-01-01

    The protostellar collapse of a molecular cloud core is usually accompanied by outflow phenomena. The latter are thought to be driven by magnetorotational processes from the central parts of the protostellar disc. While several 3D AMR/nested grid studies of outflow phenomena in collapsing magnetically supercritical dense cores have been reported in the literature, so far no such simulation has been performed using the Smoothed Particle Hydrodynamics (SPH) method. This is mainly due to intrinsic numerical difficulties in handling magnetohydrodynamics within SPH, which only recently were partly resolved. In this work, we use an approach where we evolve the magnetic field via the induction equation, augmented with stability correction and divergence cleaning schemes. We consider the collapse of a rotating core of one solar mass, threaded by a weak magnetic field initially parallel to the rotation axis so that the core is magnetically supercritical. We show, that Smoothed Particle Magnetohydrodynamics (SPMHD) is a...

  18. Hepatic venous outflow obstruction: Three similar syndromes

    Institute of Scientific and Technical Information of China (English)

    Ulas Darda Bayraktar; Soley Seren; Yusuf Bayraktar

    2007-01-01

    Our goal is to provide a detailed review of venoocclusive disease (VOD), Budd-Chiari syndrome (BCS),and congestive hepatopathy (CH), all of which results in hepatic venous outflow obstruction. This is the first article in which all three syndromes have been reviewed,enabling the reader to compare the characteristics of these disorders. The histological findings in VOD, BCS,and CH are almost identical: sinusoidal congestion and cell necrosis mostly in perivenular areas of hepatic acini which eventually leads to bridging fibrosis between adjacent central veins. Tender hepatomegaly with jaundice and ascites is common to all three conditions.However, the clinical presentation depends mostly on the extent and rapidity of the outflow obstruction.Although the etiology and treatment are completely different in VOD, BCS, and CH; the similarities in clinical manifestations and liver histology may suggest a common mechanism of hepatic injury and adaptation in response to increased sinusoidal pressure.

  19. Magnotospheric imaging of high latitude ion outflows

    Directory of Open Access Journals (Sweden)

    D. E. Garrido

    Full Text Available High latitude ion outflows mostly consist of upward streaming O+ and He+ emanating from the ionosphere. At heights above 1000 km, these flows consist of cold and hot components which resonantly scatter solar extreme ultraviolet (EUV light, however, the ion populations respond differently to Doppler shifting resulting from the large relative velocities between the ions and the Sun. The possibility of optical detection of the Doppler effect on the scattering rate will be discussed for the O+ (83.4 nm ions. We have contrasted the EUV solar resonance images of these outflows by simulations of the 30.4 nm He+ and 83.4 nm O+ emissions for both quiet and disturbed geomagnetic conditions. Input data for the 1000 km level has been obtained from the EICS instrument aboard the Dynamics Explorer satellite. Our results show emission rates of 50 and 56 milli-Rayleighs at 30.4 nm for quiet and disturbed conditions and 65 and 75 milli-Rayleighs at 83.4 nm for quiet and disturbed conditions, respectively, obtained for a polar orbiting satellite and viewing radially outward. We also find that an imager at an equatorial distance of 9 RE or more is in a favourable position for detecting ion outflows, particularly when the plasmapause is depressed in latitude. However, an occultation disk is necessary to obscure the bright plasmaspheric emissions.

  20. DLA kinematics and outflows from starburst galaxies

    CERN Document Server

    Razoumov, Alexei O

    2008-01-01

    We present results from a numerical study of the multiphase interstellar medium in sub-Lyman-break galaxy protogalactic clumps. Such clumps are abundant at z=3 and are thought to be a major contributor to damped Ly-alpha absorption. We model the formation of winds from these clumps and show that during star formation episodes they feature outflows with neutral gas velocity widths up to several hundred km/s. Such outflows are consistent with the observed high-velocity dispersion in DLAs. In our models thermal energy feedback from winds and supernovae results in efficient outflows only when cold (~ 300 K), dense (> 100 msun/pc^3) clouds are resolved at grid resolution of 12 pc. At lower 24 pc resolution the first signs of the multiphase medium are spotted; however, at this low resolution thermal injection of feedback energy cannot yet create hot expanding bubbles around star-forming regions -- instead feedback tends to erase high-density peaks and suppress star formation. At 12 pc resolution feedback compresses...

  1. Hot Electromagnetic Outflows I: Acceleration and Spectra

    CERN Document Server

    Russo, Matthew

    2013-01-01

    The theory of cold, relativistic, magnetohydrodynamic outflows is generalized by the inclusion of an intense radiation source. In some contexts, such the breakout of a gamma-ray burst jet from a star, the outflow is heated to a high temperature at a large optical depth. Eventually it becomes transparent and is pushed to a higher Lorentz factor by a combination of the Lorentz force and radiation pressure. We obtain its profile, both inside and outside the fast magnetosonic critical point, when the poloidal magnetic field is radial and monopolar. Most of the energy flux is carried by the radiation field and the toroidal magnetic field that is wound up close to the rapidly rotating engine. Although the entrained matter carries little energy, it couples the radiation field to the magnetic field. Then the fast critical point is pushed inward from infinity and, above a critical radiation intensity, the outflow is accelerated mainly by radiation pressure. We identify a distinct observational signature of this hybrid...

  2. Outflows of stars due to quasar feedback

    CERN Document Server

    Zubovas, Kastytis; Sazonov, Sergey; Sunyaev, Rashid

    2013-01-01

    Quasar feedback outflows are commonly invoked to drive gas out of galaxies in the early gas-rich epoch to terminate growth of galaxies. Here we present simulations that show that AGN feedback may drive not only gas but also stars out of their host galaxies under certain conditions. The mechanics of this process is as following: (1) AGN-driven outflows accelerate and compress gas filling the host galaxy; (2) the accelerated dense shells become gravitationally unstable and form stars on radial trajectories. For the spherically symmetric initial conditions explored here, the black hole needs to exceed the host's M_sigma mass by a factor of a few to accelerate the shells and the new stars to escape velocities. We discuss potential implications of these effects for the host galaxies: (i) radial mixing of bulge stars with the rest of the host; (ii) contribution of quasar outflows to galactic fountains as sources of high-velocity clouds; (iii) wholesale ejection of hyper velocity stars out of their hosts, giving ris...

  3. Herschel Planetary Nebula Survey (HerPlaNS). First detection of OH+ in planetary nebulae

    NARCIS (Netherlands)

    Aleman, I.; Ueta, T.; Ladjal, D.; Exter, K.M.; Kastner, J.H.; Montez, R.; Tielens, A.G.G.M.; Chu, Y.-H.; Izumiura, H.; McDonald, I.; Sahai, R.; Siódmiak, N.; Szczerba, R.; Hoof, van P. A. M.; Villaver, E.; Vlemmings, W.; Wittkowski, M.; Zijlstra, A.A.

    2014-01-01

    We report the first detections of OH+emission in planetary nebulae (PNe). As part of an imaging and spectroscopy survey of 11 PNe in the far-IR using the PACS and SPIRE instruments aboard the HerschelSpace Observatory, we performed a line survey in these PNe over the entire spectral range between 51

  4. Enhanced gamma-ray activity from the Crab nebula

    Science.gov (United States)

    Buehler, R.; Ciprini, S.

    2016-01-01

    Preliminary LAT analysis indicates enhanced gamma-ray activity from the Crab nebula. The daily-averaged gamma-ray emission (E > 100 MeV) from the direction of the Crab Nebula has surpassed 4.0 x 10^-6 ph cm^-2 s^-1 five times in the last 12 days.

  5. X-ray Pulsar in the Crab Nebula.

    Science.gov (United States)

    Fritz, G; Henry, R C; Meekins, J F; Chubb, T A; Friedman, H

    1969-05-09

    X-ray pulsations have been observed in the Crab Nebula at a frequency closely matching the radio and optical pulsations. About 5 percent of the total x-ray power of the nebula appears in the pulsed component. The x-ray pulsations have the form of a main pulse and an interpulse separated by about 12 milliseconds.

  6. A model for the 19th century eruption of Eta Carinae: CSM interaction like a scaled-down Type IIn Supernova

    Science.gov (United States)

    Smith, Nathan

    2013-03-01

    This paper proposes a simple model for the 19th century eruption of Eta Carinae that consists of two components: (1) a strong wind (dot{M}=0.33 M_{{odot }} yr-1; v∞ = 200 km s-1), blowing for 30 yr, followed by (2) a 1050 erg explosion (10 M⊙; 750-1000 km s-1) occurring in 1844. The ensuing collision between the fast ejecta and the dense circumstellar material (CSM) causes an increase in brightness observed at the end of 1844, followed by a sustained high-luminosity phase lasting for 10-15 yr that provides a close match to the observed historical light curve. The emergent luminosity is powered by converting kinetic energy to radiation through CSM interaction, analogous to the process occurring in more luminous Type IIn supernovae, except with ˜10 times lower explosion energy and at slower speeds (causing a longer duration and lower emergent luminosity). We demonstrate that such an explosive event not only provides a natural explanation for the light-curve evolution, but also accounts for a number of puzzling attributes of the highly scrutinized Homunculus, including: (1) rough equipartition of total radiated and kinetic energy in the event, (2) the double-shell structure of the Homunculus, with a thin massive outer shell (corresponding to the coasting cold dense shell) and a thicker inner layer (between the cold dense shell and the reverse shock), (3) the apparent single age and Hubble-like flow of the Homunculus resulting from the thin swept-up shell, (4) the complex mottled appearance of the polar lobes in Hubble Space Telescope images, arising naturally from Raleigh-Taylor or Vishniac instabilities at the contact discontinuity of the shock, (5) efficient and rapid dust formation, which has been observed in the post-shock zones of Type IIn supernovae, and (6) the fast (3000-5000 km s-1) material outside the Homunculus, arising from the acceleration of the forward shock upon exiting the dense CSM. In principle, the bipolar shape could be explained borrowing

  7. A Robust Measurement of the Mass Outflow Rate of the Galactic Outflow from NGC 6090

    CERN Document Server

    Chisholm, John; Leitherer, Claus; Chen, Yanmei

    2016-01-01

    To evaluate the impact of stellar feedback, it is critical to estimate the mass outflow rates of galaxies. Past estimates have been plagued by uncertain assumptions about the outflow geometry, metallicity, and ionization fraction. Here we use Hubble Space Telescope ultraviolet spectroscopic observations of the nearby starburst NGC 6090 to demonstrate that many of these quantities can be constrained by the data. We use the Si~{\\sc IV} absorption lines to calculate the scaling of velocity (v), covering fraction (C$_f$), and density with distance from the starburst (r), assuming the Sobolev optical depth and a velocity law of the form: $v \\propto(1 -R_i/r )^\\beta$ (were R$_i$ is the inner outflow radius). We find that the velocity ($\\beta$=0.43) is consistent with an outflow driven by an r$^{-2}$ force, while the scaling of the covering fraction ($C_f \\propto r^{-0.82}$) suggests that cool clouds in the outflow are in pressure equilibrium with an adiabatically expanding medium. We use the column densities of fou...

  8. Extreme Particle Acceleration via Magnetic Reconnection in the Crab Nebula

    Science.gov (United States)

    Cerutti, Benoit; Uzdensky, D. A.; Begelman, M. C.

    2012-01-01

    The discovery by Agile and Fermi of intense day-long synchrotron gamma-ray flares above 100 MeV in the Crab Nebula challenges classical models of pulsar wind nebulae and particle acceleration. We argue that the flares are powered by magnetic reconnection in the nebula. Using relativistic test-particle simulations, we show that particles are naturally focused into a thin fan beam, deep inside the reconnection layer where the magnetic field is small. The particles then suffer less from synchrotron losses and pile up at the maximum energy given by the electric potential drop in the layer. Applying this model to the Crab Nebula, we find that the emerging synchrotron emission spectrum above 100 MeV is consistent with the September 2010 flare observations. No detectable emission is expected at other wavelengths. This scenario provides a viable explanation for the Crab Nebula gamma-ray flares.

  9. DA495 - an aging pulsar wind nebula

    CERN Document Server

    Kothes, R; Reich, W; Safi-Harb, S; Arzoumanian, Z

    2008-01-01

    We present a radio continuum study of the pulsar wind nebula (PWN) DA 495 (G65.7+1.2), including images of total intensity and linear polarization from 408 to 10550 MHz based on the Canadian Galactic Plane Survey and observations with the Effelsberg 100-m Radio Telescope. Removal of flux density contributions from a superimposed \\ion{H}{2} region and from compact extragalactic sources reveals a break in the spectrum of DA 495 at 1.3 GHz, with a spectral index ${\\alpha}={-0.45 \\pm 0.20}$ below the break and ${\\alpha}={-0.87 \\pm 0.10}$ above it (${S}_\

  10. Element Masses in the Crab Nebula

    Science.gov (United States)

    Sibley, Adam R.; Katz, Andrea M.; Satterfield, Timothy J.; Vanderveer, Steven J.; MacAlpine, Gordon M.

    2016-10-01

    Using our previously published element abundance or mass-fraction distributions in the Crab Nebula, we derived actual mass distributions and estimates for overall nebular masses of hydrogen, helium, carbon, nitrogen, oxygen and sulfur. As with the previous work, computations were carried out for photoionization models involving constant hydrogen density and also constant nuclear density. In addition, employing new flux measurements for [Ni ii] λ7378, along with combined photoionization models and analytic computations, a nickel abundance distribution was mapped and a nebular stable nickel mass estimate was derived.

  11. Kinematic Distance of Galactic Planetary Nebulae

    CERN Document Server

    Yang, A Y; Zhu, H; Leahy, D A; Wu, D

    2016-01-01

    We construct \\HI~absorption spectra for 18 planetary nebulae (PNe) and their background sources using the data from the International Galactic Plane Survey. We estimate the kinematic distances of these PNe, among which 15 objects' kinematic distances are obtained for the first time. The distance uncertainties of 13 PNe range from 10% to 50%, which is a significant improvement with uncertainties of a factor two or three smaller than most of previous distance measurements. We confirm that PN G030.2-00.1 is not a PN because of its large distance found here.

  12. A large bubble around the Crab Nebula

    Science.gov (United States)

    Romani, Roger W.; Reach, William T.; Koo, Bon Chul; Heiles, Carl

    1990-01-01

    IRAS and 21 cm observations of the interstellar medium around the Crab nebula show evidence of a large bubble surrounded by a partial shell. If located at the canonical 2 kpc distance of the Crab pulsar, the shell is estimated to have a radius of about 90 pc and to contain about 50,000 solar masses of swept-up gas. The way in which interior conditions of this bubble can have important implications for observations of the Crab are described, and the fashion in which presupernova evolution of the pulsar progenitor has affected its local environment is described.

  13. The Present and Future of Planetary Nebula Research. A White Paper by the IAU Planetary Nebula Working Group

    CERN Document Server

    Kwitter, K B; Peña, M; Stanghellini, L; Corradi, R L M; DeMarco, O; Fang, X; Henry, R B C; Karakas, A I; Liu, X -W; López, J A; Manchado, A; Parker, Q A

    2014-01-01

    We present a summary of current research on planetary nebulae and their central stars, and related subjects such as atomic processes in ionized nebulae, AGB and post-AGB evolution. Future advances are discussed that will be essential to substantial improvements in our knowledge in the field.

  14. The Prevalence of Gas Outflows in Type 2 AGNs. II. 3D Biconical Outflow Models

    Science.gov (United States)

    Bae, Hyun-Jin; Woo, Jong-Hak

    2016-09-01

    We present 3D models of biconical outflows combined with a thin dust plane for investigating the physical properties of the ionized gas outflows and their effect on the observed gas kinematics in type 2 active galactic nuclei (AGNs). Using a set of input parameters, we construct a number of models in 3D and calculate the spatially integrated velocity and velocity dispersion for each model. We find that three primary parameters, i.e., intrinsic velocity, bicone inclination, and the amount of dust extinction, mainly determine the simulated velocity and velocity dispersion. Velocity dispersion increases as the intrinsic velocity or the bicone inclination increases, while velocity (i.e., velocity shifts with respect to systemic velocity) increases as the amount of dust extinction increases. Simulated emission-line profiles well reproduce the observed [O iii] line profiles, e.g., narrow core and broad wing components. By comparing model grids and Monte Carlo simulations with the observed [O iii] velocity-velocity dispersion distribution of ˜39,000 type 2 AGNs, we constrain the intrinsic velocity of gas outflows ranging from ˜500 to ˜1000 km s-1 for the majority of AGNs, and up to ˜1500-2000 km s-1 for extreme cases. The Monte Carlo simulations show that the number ratio of AGNs with negative [O iii] velocity to AGNs with positive [O iii] velocity correlates with the outflow opening angle, suggesting that outflows with higher intrinsic velocity tend to have wider opening angles. These results demonstrate the potential of our 3D models for studying the physical properties of gas outflows, applicable to various observations, including spatially integrated and resolved gas kinematics.

  15. Explosions Triggered by Violent Binary-Star Collisions: Application to Eta Carinae and other Eruptive Transients

    CERN Document Server

    Smith, Nathan

    2010-01-01

    This paper discusses a model where a violent periastron collision of stars in an eccentric binary system induces an eruption or explosion seen as a brief transient source, attributed to LBVs, SN impostors, or other transients. The key ingredient is that an evolved primary increases its photospheric radius on relatively short timescales, to a point where the radius is comparable to or larger than the periastron separation in an eccentric binary. In such a configuration, a violent and sudden collision would ensue, possibly leading to substantial mass ejection instead of a binary merger. Repeated periastral grazings in an eccentric system could quickly escalate to a catastrophic encounter, wherein the companion star actually plunges deep inside the photosphere of a bloated primary during periastron, as a result of the primary star increasing its own radius. This is motivated by the case of $\\eta$~Carinae, where such a collision must have occured if conventional estimates of the present-day orbit are correct, and...

  16. LBVs AND THE NATURE OF THE S DOR CYCLES: THE CASE OF AG CARINAE

    Directory of Open Access Journals (Sweden)

    J. H. Groh

    2008-01-01

    Full Text Available Presentamos los resultados de un análisis espectroscópico detallado sobre 20 a~nos de observaciones de AG Carinae, usando el código de transferencia radiativa llamado CMFGEN. Entre las conclusiones de este trabajo, resaltamos la importancia de incluir efectos dependientes del tiempo en el análisis del ciclo completo de S Dor. Hemos obtenido que la tasa de pérdida de masa es aproximadamente constante durante las fases fras, implicando que las erupciones en los objetos de tipo S Dor comienzan bastante más temprano que durante el máximo observado en la curva de luz visual. Hemos determinado ademías que los ciclos S Dor son, en ultima instancia, consecuencia de un aumento/disminución del radio hidrostático en combinación con una pseudo-fotosfera.

  17. Deep census of variable stars in a VLT/VIMOS field in Carina

    CERN Document Server

    Pietrukowicz, P; Fernández, J M; Pietrzynski, G; Ruiz, M T; Gieren, W; Diaz, R F; Zoccali, M; Hempel, M

    2009-01-01

    We have searched for variable stars in deep V-band images of a field towards the Galactic plane in Carina. The images were taken with VIMOS instrument at ESO VLT during 4 contiguous nights in April 2005. We detected 348 variables among 50897 stars in the magnitude range between V=15.4 and V=24.5 mag. Upon detection, we classified the variables by direct eye inspection of their light curves. All variable objects but 9 OGLE transits in the field are new discoveries. We provide a complete catalog of all variables which includes eclipsing/ellipsoidal binaries, miscellaneous pulsators (mostly delta Scuti-type variables), stars with flares and other (irregular and likely long-period) variables. Only two of the stars in our sample are known to host planets. Our result give some implications for future large variability surveys.

  18. XMM-Newton Observations of the 2003 X-Ray Minimum of Eta Carinae

    Science.gov (United States)

    Hamaguchi, K.; Corcoran, M. F.; White, N. E.; Damineli, A.; Davidson, K.; Gull, T. R.

    2004-01-01

    The XMM-Newton X-ray observatory took part in the multi-wavelength observing campaign of the massive, evolved star Eta Carinae in 2003 during its recent X-ray minimum in June 2003. This paper reports on the first results of these observations, which were performed (1) before the minimum (five times in January, 2003), (2) near the X-ray maximum just before the minimum (two times in June) and (3) during the minimum (four times in July-August). Hard X-ray emission from the point source of Eta Carinae was detected even during the minimum. The observed flux above 3 keV was approx. 3x10(exp -12) ergs cm(exp -2)/s, which is about one percent of the flux before the minimum. Light curves from the individual observations show no time variability on the scale of a few kilo-seconds. Changes in the spectral shape occurred, but these changes were smaller than expected if the minimum is produced solely by an increase of hydrogen column density. Fits of the hard X-Ray source by an absorbed 1T model show a constant plasma temperature at around 5 keV and an increase of column density from 5x10(exp 22) cm(exp -2) to 2x10(exp 23) cm(exp -2). The spectra below 6 keV significantly deviate from the models that fit the higher energy emission. The X-ray minimum seems to be dominated by an apparent decrease of the emission measure, suggesting that the brightest part of the X-ray emitting region is completely obscured during the minimum in the form of an eclipse. Partial covering plasma emission models might be considered for the spectral variation. The spectra also showed strong iron K line emission from both hot and cold gases, and weak line emission from Ni, Ca, Ar, S and Si.

  19. FITTING PHOTOIONIZATION MODELS TO PLANETARY NEBULAE

    Directory of Open Access Journals (Sweden)

    J. Bohigas

    2009-01-01

    Full Text Available Good to excellent photoionization models based on the Cloudy code were obtained for 13 out of 19 spectra of planetary nebulae. The two most important assumptions are that the photoionizing continuum is a Rauch model star, with gravity set by the condition that the stellar mass must be 1 M , and density is constant and determined from the observed [S II]6717/6731 ratio. The temperature and luminosity of the central star, the inner radius of the nebula and the abundance of carbon are treated as free parameters in each model run, destined to obtain the best possible t to the relative intensities of He II 4686, [O III]5007 and [N II]6584. Observed and modeled nebular temperatures derived from [N II] (6548+6584 /5755 agree within 10%, but models usually underestimate temperatures found from [O III] (4959+5007 /4363, more so when the slit does not cover the in-depth extent of the ionized region. Helium, nitrogen, oxygen, neon, sulfur and argon model abundances are uncertain at the 15%, 15%, 10%, 7%, 30% and 7% level. It is shown that neon abundance in PNe has been consistently overestimated, and an alternative ionization correction factor is recommended.

  20. Dark nebulae, dark lanes, and dust belts

    CERN Document Server

    Cooke, Antony

    2012-01-01

    As probably the only book of its type, this work is aimed at the observer who wants to spend time with something less conventional than the usual fare. Because we usually see objects in space by means of illumination of one kind or another, it has become routine to see them only in these terms. However, part of almost everything that we see is the defining dimension of dark shading, or even the complete obscuration of entire regions in space. Thus this book is focused on everything dark in space: those dark voids in the stellar fabric that mystified astronomers of old; the dark lanes reported in many star clusters; the magical dust belts or dusty regions that have given so many galaxies their identities; the great swirling 'folds' that we associate with bright nebulae; the small dark feature detectable even in some planetary nebulae; and more. Many observers pay scant attention to dark objects and details. Perhaps they are insufficiently aware of them or of the viewing potential they hold, but also it may be...

  1. HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA

    Science.gov (United States)

    2002-01-01

    A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This picture shows a Hubble Space Telescope image of the inner parts of the Crab. The pulsar itself is visible as the left of the pair of stars near the center of the frame. Surrounding the pulsar is a complex of sharp knots and wisp-like features. This image is one of a sequence of Hubble images taken over the course of several months. This sequence shows that the inner part of the Crab Nebula is far more dynamic than previously understood. The Crab literally 'changes it stripes' every few days as these wisps stream away from the pulsar at half the speed of light. The Hubble Space Telescope photo was taken Nov. 5, 1995 by the Wide Field and Planetary Camera 2 at a wavelength of around 550 nanometers, in the middle of the visible part of the electromagnetic spectrum. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

  2. Si isotope homogeneity of the solar nebula

    Energy Technology Data Exchange (ETDEWEB)

    Pringle, Emily A.; Savage, Paul S.; Moynier, Frédéric [Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130 (United States); Jackson, Matthew G. [Department of Earth Science, University of California, Santa Barbara, CA 93109 (United States); Barrat, Jean-Alix, E-mail: eapringle@wustl.edu, E-mail: savage@levee.wustl.edu, E-mail: pringle@ipgp.fr, E-mail: moynier@ipgp.fr, E-mail: jackson@geol.ucsb.edu, E-mail: Jean-Alix.Barrat@univ-brest.fr [Université Européenne de Bretagne, Université de Brest, CNRS UMR 6538 (Domaines Océaniques), I.U.E.M., Place Nicolas Copernic, F-29280 Plouzané Cedex (France)

    2013-12-20

    The presence or absence of variations in the mass-independent abundances of Si isotopes in bulk meteorites provides important clues concerning the evolution of the early solar system. No Si isotopic anomalies have been found within the level of analytical precision of 15 ppm in {sup 29}Si/{sup 28}Si across a wide range of inner solar system materials, including terrestrial basalts, chondrites, and achondrites. A possible exception is the angrites, which may exhibit small excesses of {sup 29}Si. However, the general absence of anomalies suggests that primitive meteorites and differentiated planetesimals formed in a reservoir that was isotopically homogenous with respect to Si. Furthermore, the lack of resolvable anomalies in the calcium-aluminum-rich inclusion measured here suggests that any nucleosynthetic anomalies in Si isotopes were erased through mixing in the solar nebula prior to the formation of refractory solids. The homogeneity exhibited by Si isotopes may have implications for the distribution of Mg isotopes in the solar nebula. Based on supernova nucleosynthetic yield calculations, the expected magnitude of heavy-isotope overabundance is larger for Si than for Mg, suggesting that any potential Mg heterogeneity, if present, exists below the 15 ppm level.

  3. Detecting Abundance Variations in Planetary Nebulae

    Science.gov (United States)

    Monteiro, H.; Santos, P. M.; Falceta-Gonçalves, D.

    2014-04-01

    Empirical methods of investigating chemical abundances are still widely used as a primary tool to study planetary nebulae (PNe) as well as HII regions. In this work we investigate the capacity of the empirical abundance determination methods to recover pre-defined parameters and abundance variations in a realistically modeled planetary nebula. To perform the test we use a threedimensional density structure obtained from a hydrodynamical simulation which is fed through a threedimensional photoionization code. The density structure is an asymetrical and inhomogeneous elongated closed shell. The input parameters used, such as, ionizing source, density, and chemical abundances are typical values of type I PNe. The model emissivities are then projected in the line of sight and emission line maps are generated, which are used to obtain the temperature and density diagnostics. The diagnostics and line emission maps are then used to obtain spatially resolved maps of the abundances. In this work we use the method described above to investigate abundances for two distinct orientations of the density structure. Our results show that for typical signal to noise ratios obtained from long-slit spectroscopy, only large abundance variations can be determined with good precision.

  4. Investigating the nature of the Fried Egg nebula: CO mm-line and optical spectroscopy of IRAS 17163-3907

    CERN Document Server

    Wallström, Sofia H J; Lagadec, E; Black, J H; Oudmaijer, R D; Justtanont, K; van Winckel, H; Zijlstra, A A

    2015-01-01

    Through CO mm-line and optical spectroscopy, we investigate the properties of the Fried Egg nebula IRAS 17163-3907, which has recently been proposed to be one of the rare members of the yellow hypergiant class. The CO J=2-1 and J=3-2 emission arises from a region within 20" of the star and is clearly associated with the circumstellar material. The CO lines show a multi-component asymmetrical profile, and an unexpected velocity gradient is resolved in the east-west direction, suggesting a bipolar outflow. This is in contrast with the apparent symmetry of the dust envelope as observed in the infrared. The optical spectrum of IRAS 17163-3907 between 5100 and 9000 {\\AA} was compared with that of the archetypal yellow hypergiant IRC+10420 and was found to be very similar. These results build on previous evidence that IRAS 17163-3907 is a yellow hypergiant.

  5. A resolved outflow of matter from a Brown Dwarf

    CERN Document Server

    Whelan, E T; Bacciotti, F; Natta, A; Testi, L; Randich, S; Whelan, Emma T.; Ray, Thomas P.; Bacciotti, Francesca; Natta, Antonella; Testi, Leonardo; Randich, Sofia

    2005-01-01

    The birth of stars involves not only accretion but also, counter-intuitively, the expulsion of matter in the form of highly supersonic outflows. Although this phenomenon has been seen in young stars, a fundamental question is whether it also occurs amongst newborn brown dwarfs: these are the so-called 'failed stars', with masses between stars and planets, that never manage to reach temperatures high enough for normal hydrogen fusion to occur. Recently, evidence for accretion in young brown dwarfs has mounted, and their spectra show lines that are suggestive of outflows. Here we report spectro-astrometric data that spatially resolve an outflow from a brown dwarf. The outflow's characteristics appear similar to, but on a smaller scale than, outflows from normal young stars. This result suggests that the outflow mechanism is universal, and perhaps relevant even to the formation of planets.

  6. A resolved outflow of matter from a brown dwarf.

    Science.gov (United States)

    Whelan, Emma T; Ray, Thomas P; Bacciotti, Francesca; Natta, Antonella; Testi, Leonardo; Randich, Sofia

    2005-06-01

    The birth of stars involves not only accretion but also, counter-intuitively, the expulsion of matter in the form of highly supersonic outflows. Although this phenomenon has been seen in young stars, a fundamental question is whether it also occurs among newborn brown dwarfs: these are the so-called 'failed stars', with masses between stars and planets, that never manage to reach temperatures high enough for normal hydrogen fusion to occur. Recently, evidence for accretion in young brown dwarfs has mounted, and their spectra show lines that are suggestive of outflows. Here we report spectro-astrometric data that spatially resolve an outflow from a brown dwarf. The outflow's characteristics appear similar to, but on a smaller scale than, outflows from normal young stars. This result suggests that the outflow mechanism is universal, and perhaps relevant even to the formation of planets.

  7. The planetary nebula Abell 48 and its [WN4] nucleus

    CERN Document Server

    Frew, David J; Parker, Q A; Stupar, M; Wachter, S; DePew, K; Danehkar, A; Fitzgerald, M F

    2013-01-01

    We have conducted a detailed multi-wavelength study of the peculiar planetary nebula Abell 48 and its central star. We present evidence for a new classification of the nucleus as a helium-rich, hydrogen-deficient star of type [WN4], one of only two currently known examples of its type. The evidence for either a massive WN or a low-mass [WN] interpretation is critically examined, and we firmly conclude that Abell 48 is a planetary nebula around an evolved low-mass star, rather than a Population I ejecta nebula. Importantly, the surrounding nebula has a morphology typical of planetary nebulae, and is not enriched in nitrogen, and thus not the 'peeled atmosphere' of a massive star. We estimate a distance of 1.6 kpc and a reddening, E(B-V) = 1.90 mag, the latter value clearly showing the nebula lies on the near side of the Galactic bar, and therefore cannot be a massive WN star. The planetary nebula has an ionized mass (0.3 M_sun) and electron density (740 cm^-3) typical of somewhat evolved objects. The observed ...

  8. Interferometric Mapping of Perseus Outflows with MASSES

    Science.gov (United States)

    Stephens, Ian; Dunham, Michael; Myers, Philip C.; MASSES Team

    2017-01-01

    The MASSES (Mass Assembly of Stellar Systems and their Evolution with the SMA) survey, a Submillimeter Array (SMA) large-scale program, is mapping molecular lines and continuum emission about the 75 known Class 0/I sources in the Perseus Molecular Cloud. In this talk, I present some of the key results of this project, with a focus on the CO(2-1) maps of the molecular outflows. In particular, I investigate how protostars inherit their rotation axes from large-scale magnetic fields and filamentary structure.

  9. ATOMIC HYDROGEN IN A GALACTIC CENTER OUTFLOW

    Energy Technology Data Exchange (ETDEWEB)

    McClure-Griffiths, N. M.; Green, J. A.; Hill, A. S. [Australia Telescope National Facility, CSIRO Astronomy and Space Science, Marsfield, NSW 2122 (Australia); Lockman, F. J. [National Radio Astronomy Observatory, Green Bank, WV 24944 (United States); Dickey, J. M. [School of Physics and Mathematics, University of Tasmania, TAS 7001 (Australia); Gaensler, B. M.; Green, A. J., E-mail: naomi.mcclure-griffiths@csiro.au [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)

    2013-06-10

    We describe a population of small, high-velocity, atomic hydrogen clouds, loops, and filaments found above and below the disk near the Galactic center. The objects have a mean radius of 15 pc, velocity widths of {approx}14 km s{sup -1}, and are observed at |z| heights up to 700 pc. The velocity distribution of the clouds shows no signature of Galactic rotation. We propose a scenario where the clouds are associated with an outflow from a central star-forming region at the Galactic center. We discuss the clouds as entrained material traveling at {approx}200 km s{sup -1} in a Galactic wind.

  10. Functional Anatomy of the Outflow Facilities.

    Science.gov (United States)

    Pizzirani, Stefano; Gong, Haiyan

    2015-11-01

    In order to understand the pathophysiology, select optimal therapeutic options for patients and provide clients with honest expectations for cases of canine glaucoma, clinicians should be familiar with a rational understanding of the functional anatomy of the ocular structures involved in this group of diseases. The topographical extension and the structural and humoral complexity of the regions involved with the production and the outflow of aqueous humor undergo numerous changes with aging and disease. Therefore, the anatomy relative to the fluid dynamics of aqueous has become a pivotal yet flexible concept to interpret the different phenotypes of glaucoma.

  11. ANAESTHESIA FOR EVALUATION AND EXCISION OF TRACHEAL TUMOUR AT CARINA EXTENDING INTO RIGHT MAIN BRONCHUS: CASE REPORT

    Directory of Open Access Journals (Sweden)

    Deepraj Singh

    2014-04-01

    Full Text Available A tracheal tumor at carinal angle is uncommon. Presented here is an interesting case of a 22 year old, HBsAg positive female with a tracheal tumor at carina extending into the right main bronchus. The patient reported shortness of breath along with fatigue and cough. Routine and other appropriate investigations were done during which X-ray chest and CT scan revealed right lung collapse with ipsilateral shift of mediastinum. Telescopic evaluation and biopsy performed under general anesthesia using supraglottic Jet Ventilation further revealed proliferative growth arising from the anterior wall of the carina extending into the right main bronchus. Subsequently, excision of the tumor through tracheotomy under general anesthesia was carried out. The patient recovered completely with no postoperative complications.

  12. Misalignment of Magnetic Fields and Outflows in Protostellar Cores

    OpenAIRE

    Hull, Charles L. H.; Plambeck, Richard L.; Bolatto, Alberto D.; Bower, Geoffrey C.; Carpenter, John M.; Crutcher, Richard M.; Fiege, Jason D.; Franzmann, Erica; Hakobian, Nicholas S.; Heiles, Carl; Houde, Martin; Hughes, A. Meredith; Jameson, Katherine; Kwon, Woojin; Lamb, James W.

    2012-01-01

    We present results of λ1.3 mm dust-polarization observations toward 16 nearby, low-mass protostars, mapped with ~2."5 resolution at CARMA. The results show that magnetic fields in protostellar cores on scales of ~1000 AU are not tightly aligned with outflows from the protostars. Rather, the data are consistent with scenarios where outflows and magnetic fields are preferentially misaligned (perpendicular), or where they are randomly aligned. If one assumes that outflows emerge along the rotati...

  13. New observations of the high-velocity outflows of the proto-planetary nebula hen 3-1475

    Directory of Open Access Journals (Sweden)

    A. Riera

    2002-01-01

    Full Text Available La nebulosa proto-planetaria Hen 3-1475 presenta un jet optico con un alto grado de colimaci on formado por una serie de condensaciones excitadas por ondas de choque. Las zonas internas del jet muestran alt simas velocidades radiales. En este trabajo presentamos el an alisis detallado de la estructura cinem atica y de las condiciones de excitaci on de las condensaciones en base a datos espectrosc opicos de alta resoluci on espectral y a las im agenes de alta resoluci on espacial obtenidas con el HST. Discutimos las semejanzas entre el jet de Hen 3-1475 y los jets HH. Ambos presentan per les extremadamente anchos con dos picos en emisi on, una disminuci on de las velocidades radiales con la distancia a la fuente central de forma escalonada, y en ambos se hallan velocidades tangenciales altas. La interpretaci on conjunta de estas propiedades apunta a la variabilidad temporal de la velocidad de eyecci on como mecanismo responsable de la formaci on de este jet.

  14. New results form HST on fast, colimated outflows in dying stars - the primary mechanism for shaping planetary nebulae

    Science.gov (United States)

    Sahai, R.; Contreras, C.

    2003-01-01

    In this paper, we briefly describe the results from imaging surveys of young PNe and PPNe with HST, and then present new results from detailed kinematic studies of several prominent objects which support our hypothesis for shaping PNe.

  15. The Carina Project. X. On the Kinematics of Old and Intermediate-age Stellar Populations1,2

    Science.gov (United States)

    Fabrizio, M.; Bono, G.; Nonino, M.; Łokas, E. L.; Ferraro, I.; Iannicola, G.; Buonanno, R.; Cassisi, S.; Coppola, G.; Dall’Ora, M.; Gilmozzi, R.; Marconi, M.; Monelli, M.; Romaniello, M.; Stetson, P. B.; Thévenin, F.; Walker, A. R.

    2016-10-01

    We present new radial velocity (RV) measurements of old (horizontal branch) and intermediate-age (red clump) stellar tracers in the Carina dwarf spheroidal. They are based on more than 2200 low-resolution spectra collected with VIMOS at Very Large Telescope (VLT). The targets are faint (20 ≲ V ≲ 21.5 mag), but the accuracy at the faintest limit is ≤9 km s‑1. These data were complemented with RV measurements either based on spectra collected with FORS2 and FLAMES/GIRAFFE at VLT or available in the literature. We ended up with a sample of 2748 stars and among them, 1389 are candidate Carina stars. We found that the intermediate-age stellar component shows a well-defined rotational pattern around the minor axis. The western and the eastern side of the galaxy differ by +5 and ‑4 km s‑1 when compared with the main RV peak. The old stellar component is characterized by a larger RV dispersion and does not show evidence of the RV pattern. We compared the observed RV distribution with N-body simulations for a former disky dwarf galaxy orbiting a giant Milky Way–like galaxy. We rotated the simulated galaxy by 60° with respect to the major axis, we kept the observer on the orbital plane of the dwarf and extracted a sample of stars similar to the observed one. Observed and predicted {V}{rot}/σ ratios across the central regions are in remarkable agreement. This evidence indicates that Carina was a disky dwarf galaxy that experienced several strong tidal interactions with the Milky Way. Owing to these interactions, Carina transformed from a disky to a prolate spheroid and the rotational velocity transformed into random motions.

  16. The abundances of neon, sulfur, and argon in planetary nebulae

    Science.gov (United States)

    Beck, S. C.; Lacy, J. H.; Townes, C. H.; Aller, L. H.; Geballe, T. R.; Baas, F.

    1981-01-01

    New infrared observations of Ne II, Ar III, and S IV are used in optical observations of other ionization states of the considered elements to evaluate the abundances of neon, argon, and sulfur in 18 planetary nebulae. Attention is also given to one or more of the infrared lines in 18 other nebulae. It is pointed out that S IV was detected in approximately 90% of the observed objects, while Ar III was found in about 80%, and Ne II in roughly one-third. It is noted that optical observations typically include only a limited region of the nebula, while the infrared measurements frequently involve integration over the entire nebular image.

  17. X-ray Emission from the Guitar Nebula

    CERN Document Server

    Romani, R W; Yadigaroglu, I A; Romani, Roger W.; Cordes, James M.

    1997-01-01

    We have detected weak soft X-ray emission from the Pulsar Wind Nebula trailing the high velocity star PSR 2224+65 (the `Guitar Nebula'). This X-ray flux gives evidence of \\gamma~10^7 eV particles in the pulsar wind and constrains the properties of the post-shock flow. The X-ray emission is most easily understood if the shocked pulsar wind is partly confined in the nebula and if magnetic fields in this zone can grow to near equipartition values.

  18. The spatio-kinematical structure and distance of the pre-planetary nebula IRAS 19134+2131

    CERN Document Server

    Imai, Hiroshi; Morris, Mark

    2007-01-01

    Using the VLBA, we have observed H2O maser emission in the pre-planetary nebula IRAS 19134+2131(I19134), in which the H2O maser spectrum has two groups of emission features separated in radial velocity by ~100 km/s. We also obtained optical images of I19134 with the HST to locate the bipolar reflection nebula in this source for the first time. The spatio-kinematical structure of the H2O masers indicates the existence of a fast, collimated (precessing) flow having a projected extent of ~140 mas and an expansion rate of ~1.9 mas/yr on the sky plane, which gives a dynamical age of only ~40 yr. The two detected optical lobes are also separated by ~150 mas in almost the same direction as that of the collimated flow. The good agreement between the extent and orientation of the H2O maser outflow and optical lobes suggests that the lobes have been recently formed along the collimated fast flow. The positions of all of the detected maser features have been measured with respect to the reference source J1925+2106 over ...

  19. Morpho-kinematic analysis of the point-symmetric, bipolar planetary nebulae Hb 5 and K 3-17, a pathway to poly-polarity

    CERN Document Server

    López, J A; Steffen, W; Riesgo, H; Richer, M G

    2012-01-01

    The kinematics of the bipolar planetary nebulae Hb~5 and K 3-17 are investigated in detail by means of a comprehensive set of spatially resolved high spectral resolution, long-slit spectra. Both objects share particularly interesting characteristics, such as a complex filamentary, rosette-type nucleus, axial point-symmetry and very fast bipolar outflows. The kinematic information of Hb~5 is combined with {\\it HST} imagery to construct a detailed 3D model of the nebula using the code SHAPE. The model shows that the large scale lobes are growing in a non-homologous way. The filamentary loops in the core are proven to actually be secondary lobes emerging from what appears to be a randomly punctured, dense, gaseous core and the material that forms the point symmetric structure flows within the lobes with a distinct kinematic pattern and its interaction with the lobes has had a shaping effect on them. Hb~5 and K~3-17 may represent a class of fast evolving planetary nebulae that will develop poly-polar characterist...

  20. MORPHO-KINEMATIC ANALYSIS OF THE POINT-SYMMETRIC, BIPOLAR PLANETARY NEBULAE Hb 5 AND K 3-17, A PATHWAY TO POLY-POLARITY

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, J. A.; Garcia-Diaz, Ma. T.; Steffen, W.; Riesgo, H.; Richer, M. G., E-mail: jal@astrosen.unam.mx, E-mail: tere@astrosen.unam.mx, E-mail: wsteffen@astrosen.unam.mx, E-mail: hriesgo@astrosen.unam.mx, E-mail: richer@astrosen.unam.mx [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Campus Ensenada, Apdo. Postal 22860, Ensenada, B. C. (Mexico)

    2012-05-10

    The kinematics of the bipolar planetary nebulae Hb 5 and K 3-17 are investigated in detail by means of a comprehensive set of spatially resolved high spectral resolution, long-slit spectra. Both objects share particularly interesting characteristics, such as a complex filamentary, rosette-type nucleus, axial point-symmetry, and very fast bipolar outflows. The kinematic information of Hb 5 is combined with Hubble Space Telescope imagery to construct a detailed three-dimensional model of the nebula using the code SHAPE. The model shows that the large-scale lobes are growing in a non-homologous way. The filamentary loops in the core are proven to actually be secondary lobes emerging from what appears to be a randomly punctured, dense, gaseous core and the material that forms the point-symmetric structure flows within the lobes with a distinct kinematic pattern and its interaction with the lobes has had a shaping effect on them. Hb 5 and K 3-17 may represent a class of fast evolving planetary nebulae that will develop poly-polar characteristics once the nebular core evolves and expands.

  1. Assessing the internal consistency of the CARINA data base in the Pacific sector of the Southern Ocean

    Directory of Open Access Journals (Sweden)

    C. L. Sabine

    2010-07-01

    Full Text Available The CARINA project is aimed at gathering and providing secondary quality control checks on carbon and carbon-relevant hydrographic and geochemical data from cruises all across the Atlantic, Arctic and Southern Ocean. In total the project gathered 188 cruises that were not previously available to the public. Of these 188 cruises, 37 are part of the Southern Ocean. Parameters from the Southern Ocean cruises, including total carbon dioxide (TCO2, total alkalinity, oxygen, nitrate, phosphate and silicate, were examined for cruise-to-cruise consistency. pH and chlorofluorocarbons (CFCs are also part of the data base, but are not discussed here. This paper focuses on the quality control of the Southern Ocean data from the Pacific sector which consisted of 29 cruises of which 17 were included in a previous synthesis called GLODAP, 11 were new cruises from the CARINA dataset, and one cruise was included in GLODAP but was updated with new data and therefore also included in CARINA. The Pacific sector quality control procedures included crossover analysis between stations and inversion analysis of all crossover data. The GLODAP data were included into the analysis as reference cruises but without applying the GLODAP recommended adjustments so the corrections could be independently verified. The outcome of this effort is an internally consistent, high-quality carbon data set for all cruises, including the reference cruises.

  2. Eta Carinae across the 2003.5 Minimum: Analysis in the visible and near infrared spectral region

    CERN Document Server

    Nielsen, K E; Weis, K; Gull, T R; Stahl, O; Bomans, D J

    2009-01-01

    We present an analysis of the visible through near infrared spectrum of Eta Carinae and its ejecta obtained during the "Eta Carinae Campaign with the UVES at the ESO VLT". This is a part of larger effort to present a complete Eta Carinae spectrum, and extends the previously presented analyses with the HST/STIS in the UV (1240-3159 A) to 10,430 A. The spectrum in the mid and near UV is characterized by the ejecta absorption. At longer wavelengths, stellar wind features from the central source and narrow emission lines from the Weigelt condensations dominate the spectrum. However, narrow absorption lines from the circumstellar shells are present. This paper provides a description of the spectrum between 3060 and 10,430 A, including line identifications of the ejecta absorption spectrum, the emission spectrum from the Weigelt condensations and the P-Cygni stellar wind features. The high spectral resolving power of VLT/UVES enables equivalent width measurements of atomic and molecular absorption lines for element...

  3. A BUTTERFLY-SHAPED 'PAPILLON' NEBULA YIELDS SECRETS OF MASSIVE STAR BIRTH

    Science.gov (United States)

    2002-01-01

    A NASA Hubble Space Telescope view of a turbulent cauldron of starbirth, called N159, taking place 170,000 light-years away in our satellite galaxy, the Large Magellanic Cloud (LMC). Torrential stellar winds from hot newborn massive stars within the nebula sculpt ridges, arcs, and filaments in the vast cloud, which is over 150 light-years across. A rare type of compact ionized 'blob' is resolved for the first time to be a butterfly-shaped or 'Papillon' (French for 'butterfly') nebula, buried in the center of the maelstrom of glowing gases and dark dust. The unprecedented details of the structure of the Papillon, itself less than 2 light-years in size (about 2 arcseconds in the sky), are seen in the inset. A possible explanation of this bipolar shape is the outflow of gas from massive stars (over 10 times the mass of our sun) hidden in the central absorption zone. Such stars are so hot that their radiation pressure halts the infall of gas and directs it away from the stars in two opposite directions. Presumably, a dense equatorial disk formed by matter still trying to fall in onto the stars focuses the outstreaming matter into the bipolar directions. This observation is part of a search for young massive stars in the LMC. Rare are the cases where we can see massive stars so early after their birth. The red in this true-color image is from the emission of hydrogen and the yellow from high excitation ionized oxygen. The picture was taken on September 5, 1998 with the Wide Field Planetary Camera 2. The Hubble observations of the Papillon nebula were conducted by the European astronomers Mohammad Heydari-Malayeri (Paris Observatory, France) and co-investigators Michael Rosa (Space Telescope-European Coordinating Facility, European Southern Observatory, Germany), Vassilis Charmandaris (Paris Observatory), Lise Deharveng (Marseille Observatory, France), and Hans Zinnecker (Astrophysical Institute, Potsdam, Germany). Their work is submitted for publication in the European

  4. Jet driven molecular outflows in Orion

    CERN Document Server

    Rodríguez-Franco, A; Wilson, T L

    1999-01-01

    We present high sensitivity and high angular resolution images of the high velocity (vLSR>30kms^-1) CO emission in the J=1-0 and J=2-1 lines of the Orion KL region. These results reveal the morphology of the high-velocity CO emission at the most extreme velocities. High velocity emission have been only detected in two regions: BN/KL (IRc2/I) and Orion-S. The Orion-S region contains a very young (dynamical age of 10^3years), very fast (~110kms^-1) and very compact (<0.16pc) bipolar outflow. From the morphology of the high-velocity gas we estimate that the position of the powering source must be ~20'' north of FIR4. For the IRc2/I molecular outflow the morphology of the moderate velocity (<60kms^-1) gas shows a weak bipolarity around IRc2/I. The gas at the most extreme velocities does not show any bipolarity around IRc2/I, if any, it is found ~30'' north from these sources. The blue and redshifted gas at moderate velocities shows similar spatial distribution with a systematic trend for the size of the hig...

  5. Ionized Outflows from Compact Steep Spectrum Sources

    CERN Document Server

    Shih, Hsin-Yi; Kewley, Lisa

    2013-01-01

    Massive outflows are known to exist, in the form of extended emission-line regions (EELRs), around about one-third of powerful FR II radio sources. We investigate the origin of these EELRs by studying the emission-line regions around compact-steep-spectrum (CSS) radio galaxies that are younger (10$^3$ to 10$^5$ years old) versions of the FR II radio galaxies. We have searched for and analyzed the emission-line regions around 11 CSS sources by taking integral field spectra using GMOS on Gemini North. We fit the [\\ion{O}{3}] $\\lambda 5007$ line and present the velocity maps for each detected emission-line region. We find, in most cases, that the emission-line regions have multi-component velocity structures with different velocity dispersions and/or flux distributions for each component. The velocity gradients of the emission-line gas are mostly well aligned with the radio axis, suggesting a direct causal link between the outflowing gas and the radio jets. The complex velocity structure may be a result of diffe...

  6. Quasar feedback revealed by giant molecular outflows

    CERN Document Server

    Feruglio, Chiara; Piconcelli, Enrico; Menci, Nicola; Aussel, Herve'; Lamastra, Alessandra; Fiore, Fabrizio

    2010-01-01

    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...

  7. Multidimensional chemical modelling, II. Irradiated outflow walls

    CERN Document Server

    Bruderer, Simon; Doty, Steven D; van Dishoeck, Ewine F; Bourke, Tyler L

    2009-01-01

    Observations of the high-mass star forming region AFGL 2591 reveal a large abundance of CO+, a molecule known to be enhanced by far UV (FUV) and X-ray irradiation. In chemical models assuming a spherically symmetric envelope, the volume of gas irradiated by protostellar FUV radiation is very small due to the high extinction by dust. The abundance of CO+ is thus underpredicted by orders of magnitude. In a more realistic model, FUV photons can escape through an outflow region and irradiate gas at the border to the envelope. Thus, we introduce the first 2D axi-symmetric chemical model of the envelope of a high-mass star forming region to explain the CO+ observations as a prototypical FUV tracer. The model assumes an axi-symmetric power-law density structure with a cavity due to the outflow. The local FUV flux is calculated by a Monte Carlo radiative transfer code taking scattering on dust into account. A grid of precalculated chemical abundances, introduced in the first part of this series of papers, is used to ...

  8. Shocks in nova outflows. I. Thermal emission

    CERN Document Server

    Metzger, Brian D; Vurm, Indrek; Beloborodov, Andrei M; Chomiuk, Laura; Sokoloski, J L; Nelson, Thomas

    2014-01-01

    Evidence for shocks in nova outflows include (1) multiple velocity components in the optical spectra; (2) keV X-ray emission weeks to months after the outburst; (3) early radio flare on timescales of months, in excess of that predicted from the freely expanding photo-ionized gas; and (4) ~ GeV gamma-rays. We present a 1D model for the shock interaction between the fast nova outflow and a dense external shell (DES) and its associated thermal X-ray, optical, and radio emission. The forward shock is radiative initially when the density of shocked gas is highest, at which times radio emission originates from the dense cooling layer immediately downstream of the shock. The radio light curve is characterized by sharper rises to maximum and later peak times at progressively lower frequencies, with a peak brightness temperature that is approximately independent of frequency. We apply our model to the recent gamma-ray classical nova V1324 Sco, obtaining an adequate fit to the early radio maximum for reasonable assumpt...

  9. The San Pedro M\\'artir Planetary Nebula Kinematic Catalogue: Extragalactic Planetary Nebulae

    CERN Document Server

    Richer, M G; Díaz-Méndez, E; Riesgo, H; Báez, S -H; García-Díaz, Ma -T; Meaburn, J; Clark, D M; Olvera, R M Calderón; Soto, G López; Rebolo, O Toledano

    2010-01-01

    We present kinematic data for 211 bright planetary nebulae in eleven Local Group galaxies: M31 (137 PNe), M32 (13), M33 (33), Fornax (1), Sagittarius (3), NGC 147 (2), NGC 185 (5), NGC 205 (9), NGC 6822 (5), Leo A (1), and Sextans A (1). The data were acquired at the Observatorio Astron\\'omico Nacional in the Sierra de San Pedro M\\'artir using the 2.1m telescope and the Manchester Echelle Spectrometer in the light of [\\ion{O}{3}]$\\lambda$5007 at a resolution of 11 km/s. A few objects were observed in H$\\alpha$. The internal kinematics of bright planetary nebulae do not depend strongly upon the metallicity or age of their progenitor stellar populations, though small systematic differences exist. The nebular kinematics and H$\\beta$ luminosity require that the nebular shells be accelerated during the early evolution of their central stars. Thus, kinematics provides an additional argument favoring similar stellar progenitors for bright planetary nebulae in all galaxies.

  10. A Case Study in Astronomical 3-D Printing: The Mysterious Eta Carinae

    CERN Document Server

    Madura, Thomas I

    2016-01-01

    3-D printing moves beyond interactive 3-D graphics and provides an excellent tool for both visual and tactile learners, since 3-D printing can now easily communicate complex geometries and full color information. Some limitations of interactive 3-D graphics are also alleviated by 3-D printable models, including issues of limited software support, portability, accessibility, and sustainability. We describe the motivations, methods, and results of our work on using 3-D printing (1) to visualize and understand the Eta Car Homunculus nebula and central binary system and (2) for astronomy outreach and education, specifically, with visually impaired students. One new result we present is the ability to 3-D print full-color models of Eta Car's colliding stellar winds. We also demonstrate how 3-D printing has helped us communicate our improved understanding of the detailed structure of Eta Car's Homunculus nebula and central binary colliding stellar winds, and their links to each other. Attached to this article are f...

  11. HESS Observations of Pulsar Wind Nebulae

    CERN Document Server

    De Jager, O C

    2006-01-01

    The high resolution capabilities of the High Energy Stereoscopic System (HESS) introduced a new era in Gamma-Ray Astronomy, and opens a new window on pulsar wind nebula (PWN) research. A rotationally induced jet (associated with PSR B1509-58) is resolved for the first time in gamma-rays, allowing us to trace the particle transport directly, without having the complicating effect of spatially varying field distributions on the synchrotron emissivity. For PWN older or more extended than Crab (i.e. those with lower field strengths), HESS also reveals the properties of electrons contributing to the EUV/soft X-ray synchrotron bands, whereas EUV/soft X-rays suffer from severe interstellar absorption effects. Finally, HESS morphological studies of evovled PWN also allow us to directly measure the effects of assymetric reverse shock interactions due to SNR forward shock expansion into the inhomogeneous interstellar medium.

  12. High Energy Processes in Pulsar Wind Nebulae

    CERN Document Server

    Bednarek, W

    2006-01-01

    Young pulsars produce relativistic winds which interact with matter ejected during the supernova explosion and the surrounding interstellar gas. Particles are accelerated to very high energies somewhere in the pulsar winds or at the shocks produced in collisions of the winds with the surrounding medium. As a result of interactions of relativistic leptons with the magnetic field and low energy radiation (of synchrotron origin, thermal, or microwave background), the non-thermal radiation is produced with the lowest possible energies up to $\\sim$100 TeV. The high energy (TeV) gamma-ray emission has been originally observed from the Crab Nebula and recently from several other objects. Recent observations by the HESS Cherenkov telescopes allow to study for the first time morphology of the sources of high energy emission, showing unexpected spectral features. They might be also interpreted as due to acceleration of hadrons. However, theory of particle acceleration in the PWNe and models for production of radiation ...

  13. Investigating potential planetary nebula/cluster pairs

    CERN Document Server

    Bidin, Christian Moni; Bonatto, Charles; Mauro, Francesco; Turner, David; Geisler, Doug; Chene, Andres-Nicolas; Gormaz-Matamala, Alex C; Borissova, Jura; Kurtev, Radostin G; Minniti, Dante; Carraro, Giovanni; Gieren, Wolfgang

    2013-01-01

    Fundamental parameters characterizing the end-state of intermediate-mass stars may be constrained by discovering planetary nebulae (PNe) in open clusters (OCs). Cluster membership may be exploited to establish the distance, luminosity, age, and physical size for PNe, and the intrinsic luminosity and mass of its central star. Four potential PN-OC associations were investigated, to assess the cluster membership for the PNe. Radial velocities were measured from intermediate-resolution optical spectra, complemented with previous estimates in the literature. When the radial velocity study supported the PN/OC association, we analyzed if other parameters (e.g., age, distance, reddening, central star brightness) were consistent with this conclusion. Our measurements imply that the PNe VBe3 and HeFa1 are not members of the OCs NGC5999 and NGC6067, respectively, and likely belong to the background bulge population. Conversely, consistent radial velocities indicate that NGC2452/NGC2453 could be associated, but our resul...

  14. ISO Spectroscopy of Proto-Planetary Nebulae

    Science.gov (United States)

    Hrivnak, Bruce J.

    2000-01-01

    The goal of this program was to determine the chemical properties of the dust shells around protoplanetary nebulae (PPNs) through a study of their short-wavelength (6-45 micron) infrared spectra. PPNs are evolved stars in transition from the asymptotic giant branch to the planetary nebula stages. Spectral features in the 10 to 20 gm region indicate the chemical nature (oxygen- or carbon-rich), and the strengths of the features relate to the physical properties of the shells. A few bright carbon-rich PPNs have been observed to show PAH features and an unidentified 21 micron emission feature. We used the Infrared Space Observatory (ISO) to observe a sample of IRAS sources that have the expected properties of PPNs and for which we have accurate positions. Some of these have optical counterparts (proposal SWSPPN01) and some do not (SWSPPN02). We had previously observed these from the ground with near-infrared photometry and, for those with visible counterparts, visible photometry and spectroscopy, which we have combined with these new ISO data in the interpretation of the spectra. We have completed a study of the unidentified emission feature at 21 micron in eight sources. We find the shape of the feature to be the same in all of the sources, with no evidence of any substructure. The ratio of the emission peak to continuum ranges from 0.13 to 1.30. We have completed a study of seven PPNs and two other carbon-rich objects for which we had obtained ISO 2-45 micron observations. The unidentified emission features at 21 and 30 micron were detected in six sources, including four new detections of the 30 micron feature. This previously unresolved 30 micron feature was resolved and found to consist of a broad feature peaking at 27.2 micron (the "30 micron" feature) and a narrower feature peaking at 25.5 micron (the "26 micron" feature). This new 26 micron feature is detected in eight sources and is particularly strong in IRAS Z02229+6208 and 16594-4656. The unidentified

  15. Atlas of monochromatic images of planetary nebulae

    CERN Document Server

    Weidmann, W A; Valdarenas, R R Vena; Ahumada, J A; Volpe, M G; Mudrik, A

    2016-01-01

    We present an atlas of more than one hundred original images of planetary nebulae (PNe). These images were taken in a narrow-band filter centred on the nebular emission of the [N II] during several observing campaigns using two moderate-aperture telescopes, at the Complejo Astron\\'omico El Leoncito (CASLEO), and the Estaci\\'on Astrof\\'isica de Bosque Alegre (EABA), both in Argentina. The data provided by this atlas represent one of the most extensive image surveys of PNe in [N II]. We compare the new images with those available in the literature, and briefly describe all cases in which our [N II] images reveal new and interesting structures.

  16. Proposed nomenclature for Extragalactic Planetary Nebulae

    CERN Document Server

    Parker, Q A; Parker, Quentin A

    2004-01-01

    The ability to identify and distinguish between the wide variety of celestial objects benefits from application of a systematic and logical nomenclature. This often includes value-added information within the naming convention which can aid in placing the object positionally either via an RA/DEC or l,b concatenation. All new nomenclatures should be created following IAU guidelines. However as the number density of specific object types on the sky increases, as in the case of PN in external galaxies, a useful positional identifier becomes problematic. This brief but timely paper attempts to progress the debate on this vexing issue for the case of extragalactic planetary nebulae (EPN). There is a clear need to rationalise the current ad-hoc system now that many thousands of Extragalactic PN are being discovered.

  17. Planetary Nebula Surveys: Past, Present and Future

    CERN Document Server

    Parker, Quentin A

    2010-01-01

    In this review we cover the detection, identification and astrophysical importance of planetary nebulae (PN). The legacy of the historic Perek & Kohoutek and Acker et al. catalogues is briefly covered before highlighting the more recent but significant progress in PN discoveries in our Galaxy and the Magellanic Clouds. We place particular emphasis on the major MASH and the IPHAS catalogues, which, over the last decade alone, have essentially doubled Galactic and LMC PN numbers. We then discuss the increasing role and importance that multi-wavelength data is playing in both the detection of candidate PN and the elimination of PN mimics that have seriously biased previous PN compilations. The prospects for future surveys and current efforts and prospects for PN detections in external galaxies are briefly discussed due to their value both as cosmic distance indicators and as kinematical probes of galaxies and dark matter properties.

  18. Exploiting the HASH Planetary Nebula Research Platform

    CERN Document Server

    Parker, Quentin A; Frew, David J

    2016-01-01

    The HASH (Hong Kong/ AAO/ Strasbourg/ H{\\alpha}) planetary nebula research platform is a unique data repository with a graphical interface and SQL capability that offers the community powerful, new ways to undertake Galactic PN studies. HASH currently contains multi-wavelength images, spectra, positions, sizes, morphologies and other data whenever available for 2401 true, 447 likely, and 692 possible Galactic PNe, for a total of 3540 objects. An additional 620 Galactic post-AGB stars, pre-PNe, and PPN candidates are included. All objects were classified and evaluated following the precepts and procedures established and developed by our group over the last 15 years. The complete database contains over 6,700 Galactic objects including the many mimics and related phenomena previously mistaken or confused with PNe. Curation and updating currently occurs on a weekly basis to keep the repository as up to date as possible until the official release of HASH v1 planned in the near future.

  19. Measurement of Outflow Facility Using iPerfusion.

    Directory of Open Access Journals (Sweden)

    Joseph M Sherwood

    Full Text Available Elevated intraocular pressure (IOP is the predominant risk factor for glaucoma, and reducing IOP is the only successful strategy to prevent further glaucomatous vision loss. IOP is determined by the balance between the rates of aqueous humour secretion and outflow, and a pathological reduction in the hydraulic conductance of outflow, known as outflow facility, is responsible for IOP elevation in glaucoma. Mouse models are often used to investigate the mechanisms controlling outflow facility, but the diminutive size of the mouse eye makes measurement of outflow technically challenging. In this study, we present a new approach to measure and analyse outflow facility using iPerfusion™, which incorporates an actuated pressure reservoir, thermal flow sensor, differential pressure measurement and an automated computerised interface. In enucleated eyes from C57BL/6J mice, the flow-pressure relationship is highly non-linear and is well represented by an empirical power law model that describes the pressure dependence of outflow facility. At zero pressure, the measured flow is indistinguishable from zero, confirming the absence of any significant pressure independent flow in enucleated eyes. Comparison with the commonly used 2-parameter linear outflow model reveals that inappropriate application of a linear fit to a non-linear flow-pressure relationship introduces considerable errors in the estimation of outflow facility and leads to the false impression of pressure-independent outflow. Data from a population of enucleated eyes from C57BL/6J mice show that outflow facility is best described by a lognormal distribution, with 6-fold variability between individuals, but with relatively tight correlation of facility between fellow eyes. iPerfusion represents a platform technology to accurately and robustly characterise the flow-pressure relationship in enucleated mouse eyes for the purpose of glaucoma research and with minor modifications, may be applied

  20. The Spectroscopic Properties of Bright Extragalactic Planetary Nebulae

    CERN Document Server

    Richer, M G

    2006-01-01

    The properties of bright extragalactic planetary nebulae are reviewed based upon the results of low and high resolution spectroscopy. It is argued that bright extragalactic planetary nebulae from galaxies (or subsystems) with and without star formation have different distributions of central star temperature and ionization structure. As regards the chemical compositions, oxygen and neon are generally found to be unchanged as a result of the evolution of the stellar progenitors. Nitrogen enrichment may occur as a result of the evolution of the progenitors of bright planetary nebulae in all stellar populations, though this enrichment may be (more) random in old stellar populations. Helium abundances appear to be influenced by the chemical evolution of the host galaxy, with planetary nebulae in dwarf spheroidals having systematically elevated abundances. Neither the age nor the metallicity of the progenitor stellar population has a strong effect upon the kinematics observed for nebular shells. Both the range of ...

  1. Chemical composition of planetary nebulae : Including ISO results

    NARCIS (Netherlands)

    Pottasch, [No Value; Beintema, DA; Salas, JB; Feibelman, WA; Henney, WJ; Franco, J; Martos, M; Pena, M

    2002-01-01

    The method of determining abundances using Infrared Space Observatory spectra is discussed. The results for seven planetary nebula are given. Using these data, a preliminary discussion of their evolution is given.

  2. Star Formation in the Orion Nebula I: Stellar Content

    CERN Document Server

    Muench, August; Hillenbrand, Lynne; Preibisch, Thomas

    2008-01-01

    The Orion Nebula is one of the most frequently observed nearby (<1 kiloparsec) star forming regions and, consequently, the subject of a large bibliography of observations and interpretation. The summary in this chapter is bounded spatially by the blister HII region, with sources beyond the central nebula that are part of the same dynamical clustering covered in other chapters in this book. Herein are discussed panchromatic observations of the massive OB stars, the general T Tauri population, the sub-stellar sources and variable stars within the Orion Nebula. First, a brief history of 400 years of observation of the Nebula is presented. As this history is marked clearly by revelations provided in each age of new technology, recent ultra-deep X-ray surveys and high resolution multi-epoch monitoring of massive binary systems and radio stars receive special attention in this review. Topics discussed include the kinematics, multiplicity, mass distribution, rotation, and circumstellar characteristics of the pre-...

  3. Measuring the seeds of thermal ion outflow

    Science.gov (United States)

    Fernandes, Philip A.

    The ionosphere is the primary source for heavy ions which are ubiquitous in the terrestrial magnetosphere. Low-altitude energization in the auroral ionosphere results in bulk heating and transverse acceleration of ions, which begin to upwell and/or be accelerated upward by the mirror force, starting upflow and leading to the outflow process. The details of the processes that seed ion outflow at low altitudes are difficult to measure in situ and thus remain an open question. We examine the observational parameter regime in which ion upflow/outflow initiates. Emphasis is placed on making measurements of the thermal ion kinetic distribution function, allowing for accounting of processes which affect in situ plasma measurements. We consider an electrostatic analyzer (ESA) instrument capable of making the measurements necessary to quantify the roles of various heating mechanisms in initiating ion upflow in the low-altitude auroral ionosphere. We present the difficulties associated with making these measurements and identify instrument design choices that mitigate some of these measurement challenges. Analysis of ESA measurements of the thermal ion distribution function taken on the MICA auroral sounding rocket is presented. Using a Maxwellian model to replicate possible measured spectra, we calculate integrated parameters from the model and compare with equivalent parameters calculated from the in situ data. Through Liouville's theorem and the thin-sheath approximation we couple the measured and forward-modeled parameters such that measurements inside the sheath provide information about the state of the plasma outside the sheath. Throughout the MICA flight, ion upflow is observed and attributed to ambipolar electric fields and/or ion-neutral interactions. Late in the flight we observe quasi-static frictional process driving the ion temperature. Early in the flight we observe ion heating weakly correlated with ELF wave activity; our analysis suggests we must consider

  4. Lifetime of the solar nebula constrained by meteorite paleomagnetism

    Science.gov (United States)

    Wang, Huapei; Weiss, Benjamin P.; Bai, Xue-Ning; Downey, Brynna G.; Wang, Jun; Wang, Jiajun; Suavet, Clément; Fu, Roger R.; Zucolotto, Maria E.

    2017-02-01

    A key stage in planet formation is the evolution of a gaseous and magnetized solar nebula. However, the lifetime of the nebular magnetic field and nebula are poorly constrained. We present paleomagnetic analyses of volcanic angrites demonstrating that they formed in a near-zero magnetic field (core dynamo on the angrite parent body did not initiate until about 4 to 11 million years after solar system formation.

  5. Complex molecules in the Orion Kleinmann-Low nebula

    Directory of Open Access Journals (Sweden)

    Despois D.

    2014-02-01

    Full Text Available In the framework of the delivery to the early Earth of extraterrestrial molecules, we have studied complex molecular species toward the Orion Kleinmann-Low nebula. This nebula is rich in molecules as well as in nascent stars and planetary systems. We focus here on HCOOCH3, CH3OCH3 and deuterated methanol. Upper limits on species of prebiotic interest like glycine were also obtained.

  6. Stars and Planetary Nebulae in the Galactic Bulge

    CERN Document Server

    Cuisinier, F; Acker, A; Maciel, W J

    2000-01-01

    We compare the populations of Red Giant stars and Planetary Nebulae in the Galactic Bulge, in the light of recent determinations of their abundances patterns. We find both populations to be compatible. From the planetary nebulae, we find evidences that the Bulge did not form stars recently. The whole abundances pattern remains however puzzling, some elements favoring a quick evolution of the Galactic Bulge (Mg and Ti), and others a much slower one (He, O, Si, S, Ar and Ca).

  7. Orientation of Galactic Bulge Planetary Nebulae toward the Galactic Center

    CERN Document Server

    Danehkar, A

    2014-01-01

    We have used the Wide Field Spectrograph on the Australian National University 2.3-m telescope to perform the integral field spectroscopy for a sample of the Galactic planetary nebulae. The spatially resolved velocity distributions of the H$\\alpha$ emission line were used to determine the kinematic features and nebular orientations. Our findings show that some bulge planetary nebulae toward the Galactic center have a particular orientation.

  8. The Boomerang Nebula - The Coldest Region of the Universe

    Science.gov (United States)

    Sahai, Raghvendra; Nyman, Lars-Ake

    1997-01-01

    In this letter, we report such observations of the Boomerang Nebula which show it to be a unique object, consisiting of an ultra-cold and extremely massive molecular envolope, expanding at very high speed. The extreeme physical characteristics of the Boomerang Nebula reported here have never been seen before in any AGB or post-AGB object, and should spur new theoretical and obesrvational efforts to understand the nature of the mass-loss processes occurring during later stellar evolution.

  9. A MegaCam Survey of Outer Halo Satellites. VI: The Spatially Resolved Star Formation History of the Carina Dwarf Spheroidal Galaxy

    CERN Document Server

    Santana, Felipe A; de Boer, T J L; Simon, Joshua D; Geha, Marla; Côté, Patrick; Guzmán, Andrés E; Stetson, Peter; Djorgovski, S G

    2016-01-01

    We present the spatially resolved star formation history (SFH) of the Carina dwarf spheroidal galaxy, obtained from deep, wide-field g,r imaging and a metallicity distribution from the literature. Our photometry covers $\\sim2$ deg$^2$, reaching up to $\\sim10$ times the half-light radius of Carina with a completeness higher than $50\\%$ at $g\\sim24.5$, more than one magnitude fainter than the oldest turnoff. This is the first time a combination of depth and coverage of this quality has been used to derive the SFH of Carina, enabling us to trace its different populations with unprecedented accuracy. We find that Carina's SFH consists of two episodes well separated by a star formation temporal gap. These episodes occurred at old ($>10$ Gyr) and intermediate ($2$-$8$ Gyr) ages. Our measurements show that the old episode comprises the majority of the population, accounting for $54\\pm5\\%$ of the stellar mass within $1.3$ times the King tidal radius, while the total stellar mass derived for Carina is $1.60\\pm0.09\\tim...

  10. Scaling Relations Between Warm Galactic Outflows and Their Host Galaxies

    CERN Document Server

    Chisholm, John; Leitherer, Claus; Chen, Yanmei; Wofford, Aida; Lundgren, Britt

    2014-01-01

    We report on a sample of 51 nearby, star-forming galaxies observed with the Cosmic Origin Spectrograph on the Hubble Space Telescope. We calculate Si II kinematics and densities arising from warm gas entrained in galactic outflows. We use multi-wavelength ancillary data to estimate stellar masses (M$_\\ast$), star-formation rates (SFR), and morphologies. We derive significant correlations between outflow velocity and SFR$^{\\sim 0.1}$, M$_\\ast^{\\sim 0.1}$ and v$_\\text{circ}^{\\sim 1/2}$. Some mergers drive outflows faster than these relations prescribe, launching the outflow faster than the escape velocity. Calculations of the mass outflow rate reveal strong scaling with SFR$^{\\sim 1/2}$ and M$_\\ast^{\\sim 1/2}$. Additionally, mass-loading efficiency factors (mass outflow rate divided by SFR) scale approximately as M$_\\ast^{-1/2}$. Both the outflow velocity and mass-loading scaling suggest that these outflows are powered by supernovae, with only 0.7% of the total supernovae energy converted into the kinetic energ...

  11. Standing Shocks around Black Holes and Estimation of Outflow Rates

    Indian Academy of Sciences (India)

    Santabrata Das; Sandip K. Chakrabarti

    2002-03-01

    We self-consistently obtain shock locations in an accretion flow by using an analytical method. One can obtain the spectral properties, quasi-periodic oscillation frequencies and the outflowrates when the inflow parameters are known. Since temperature of the CENBOL decides the spectral states of the black hole, and also the outflow rate, the outflow rate is directly related to the spectral states.

  12. Collective outflow from a small multiple stellar system

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Thomas [Institut für Theoretische Physik, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Klaassen, Pamela D. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Mac Low, Mordecai-Mark [Department of Astrophysics, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024-5192 (United States); Schrön, Martin; Klessen, Ralf S. [Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Federrath, Christoph [Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Vic 3800 (Australia); Smith, Michael D., E-mail: tpeters@physik.uzh.ch [Centre for Astrophysics and Space Science, University of Kent, Canterbury, CT2 7NH (United Kingdom)

    2014-06-10

    The formation of high-mass stars is usually accompanied by powerful protostellar outflows. Such high-mass outflows are not simply scaled-up versions of their lower-mass counterparts, since observations suggest that the collimation degree degrades with stellar mass. Theoretically, the origins of massive outflows remain open to question because radiative feedback and fragmentation of the accretion flow around the most massive stars, with M > 15 M {sub ☉}, may impede the driving of magnetic disk winds. We here present a three-dimensional simulation of the early stages of core fragmentation and massive star formation that includes a subgrid-scale model for protostellar outflows. We find that stars that form in a common accretion flow tend to have aligned outflow axes, so that the individual jets of multiple stars can combine to form a collective outflow. We compare our simulation to observations with synthetic H{sub 2} and CO observations and find that the morphology and kinematics of such a collective outflow resembles some observed massive outflows, such as Cepheus A and DR 21. We finally compare physical quantities derived from simulated observations of our models to the actual values in the models to examine the reliability of standard methods for deriving physical quantities, demonstrating that those methods indeed recover the actual values to within a factor of two to three.

  13. Simulating Supersonic Turbulence in Galaxy Outflows

    CERN Document Server

    Scannapieco, Evan

    2010-01-01

    We present three-dimensional, adaptive mesh simulations of dwarf galaxy out- flows driven by supersonic turbulence. Here we develop a subgrid model to track not only the thermal and bulk velocities of the gas, but also its turbulent velocities and length scales. This allows us to deposit energy from supernovae directly into supersonic turbulence, which acts on scales much larger than a particle mean free path, but much smaller than resolved large-scale flows. Unlike previous approaches, we are able to simulate a starbursting galaxy modeled after NGC 1569, with realistic radiative cooling throughout the simulation. Pockets of hot, diffuse gas around individual OB associations sweep up thick shells of material that persist for long times due to the cooling instability. The overlapping of high-pressure, rarefied regions leads to a collective central outflow that escapes the galaxy by eating away at the exterior gas through turbulent mixing, rather than gathering it into a thin, unstable shell. Supersonic, turbul...

  14. Relativistic Outflows in Gamma-Ray Bursts

    CERN Document Server

    Aloy, M A

    2007-01-01

    The possibility that gamma-ray bursts (GRBs) were not isotropic emissions was devised theoretically as a way to ameliorate the huge energetic budget implied by the standard fireball model for these powerful phenomena. However, the mechanism by which after the quasy-isotropic release of a few $10^{50} $erg yields a collimated ejection of plasma could not be satisfactory explained analytically. The reason being that the collimation of an outflow by its progenitor system depends on a very complex and non-linear dynamics. That has made necessary the use of numerical simulations in order to shed some light on the viability of some likely progenitors of GRBs. In this contribution I will review the most relevant features shown by these numerical simulations and how they have been used to validate the collapsar model (for long GRBs) and the model involving the merger of compact binaries (for short GRBs).

  15. FIRE simulations: galactic outflows and their consequences

    Science.gov (United States)

    Keres, Dusan; FIRE Team

    2016-06-01

    We study gaseous outflows and their consequences in high-resolution galaxy formation simulations with explicit stellar feedback from the Feedback in Realistic Environments project. Collective, galaxy scale, effect of stellar feedback results in episodic ejections of large amount of gas and heavy elements into the circum-galactic medium. Gas ejection episodes follow strong bursts of star formation. Properties of galactic star formation and ejection episodes depend on galaxy mass and redshift and, together with gas infall and recycling, shape the evolution of the circum-galactic medium and galaxies. As a consequence, our simulated galaxies have masses, star formation histories and heavy element content in good agreement with the observed population of galaxies.

  16. An Intergalactic Magnetic Field from Quasar Outflows

    CERN Document Server

    Furlanetto, S; Furlanetto, Steven; Loeb, Abraham

    2001-01-01

    Outflows from quasars inevitably pollute the intergalactic medium (IGM) with magnetic fields. The short-lived activity of a quasar leaves behind an expanding magnetized bubble in the IGM. We model the expansion of the remnant quasar bubbles and calculate their distribution as a function magnetic field strength at different redshifts. We find that by a redshift z ~ 3, about 5-80% of the IGM volume is filled by magnetic fields with an energy density > 10% of the mean thermal energy density of a photo-ionized IGM (at ~ 10^4 K). As massive galaxies and X-ray clusters condense out of the magnetized IGM, the adiabatic compression of the magnetic field could result in the fields observed in these systems without a need for further dynamo amplification.

  17. Ice sculpture in the Martian outflow channels

    Science.gov (United States)

    Lucchitta, B. K.

    1982-01-01

    Viking Orbiter and terrestrial satellite images are examined at similar resolution to compare features of the Martian outflow channels with features produced by the movement of ice on earth, and many resemblances are found. These include the anastomoses, sinuosities, and U-shaped cross profiles of valleys; hanging valleys; linear scour marks on valley walls; grooves and ridges on valley floors; and the streamlining of bedrock highs. Attention is given to the question whether ice could have moved in the Martian environment. It is envisaged that springs or small catastrophic outbursts discharged fluids from structural outlets or chaotic terrains. These fluids built icings that may have grown into substantial masses and eventually flowed like glaciers down preexisting valleys. An alternative is that the fluids formed rivers or floods that in turn formed ice jams and consolidated into icy masses in places where obstacles blocked their flow.

  18. The Implications of Extreme Outflows from Extreme Starbursts

    CERN Document Server

    Heckman, Timothy M

    2016-01-01

    Interstellar ultraviolet absorption-lines provide crucial information about the properties of galactic outflows. In this paper, we augment our previous analysis of the systematic properties of starburst-driven galactic outflows by expanding our sample to include a rare population of starbursts with exceptionally high outflow velocities. In principle, these could be a qualitatively different phenomenon from more typical outflows. However, we find that instead these starbursts lie on, or along the extrapolation of, the trends defined by the more typical systems studied previously by us. We exploit the wide dynamic range provided by this new sample to determine scaling relations of outflow velocity with galaxy stellar mass (M*), circular velocity, star-formation rate (SFR), SFR/M*, and SFR/area. We argue that these results can be accommodated within the general interpretational framework we previously advocated, in which a population of ambient interstellar or circum-galactic clouds is accelerated by the combine...

  19. Searching for molecular outflows in Hyper-Luminous Infrared Galaxies

    CERN Document Server

    Calderón, D; Veilleux, S; Graciá-Carpio, J; Sturm, E; Lira, P; Schulze, S; Kim, S

    2016-01-01

    We present constraints on the molecular outflows in a sample of five Hyper-Luminous Infrared Galaxies using Herschel observations of the OH doublet at 119 {\\mu}m. We have detected the OH doublet in three cases: one purely in emission and two purely in absorption. The observed emission profile has a significant blueshifted wing suggesting the possibility of tracing an outflow. Out of the two absorption profiles, one seems to be consistent with the systemic velocity while the other clearly indicates the presence of a molecular outflow whose maximum velocity is about ~1500 km/s. Our analysis shows that this system is in general agreement with previous results on Ultra-luminous Infrared Galaxies and QSOs, whose outflow velocities do not seem to correlate with stellar masses or starburst luminosities (star formation rates). Instead the galaxy outflow likely arises from an embedded AGN.

  20. Evolution of active region outflows throughout an active region lifetime

    Science.gov (United States)

    Zangrilli, L.; Poletto, G.

    2016-10-01

    Context. We have shown previously that SOHO/UVCS data allow us to detect active region (AR) outflows at coronal altitudes higher than those reached by other instrumentation. These outflows are thought to be a component of the slow solar wind. Aims: Our purpose is to study the evolution of the outflows in the intermediate corona from AR 8100, from the time the AR first forms until it dissolves, after several transits at the solar limb. Methods: Data acquired by SOHO/UVCS at the time of the AR limb transits, at medium latitudes and at altitudes ranging from 1.5 to 2.3 R⊙, were used to infer the physical properties of the outflows through the AR evolution. To this end, we applied the Doppler dimming technique to UVCS spectra. These spectra include the H i Lyα line and the O vi doublet lines at 1031.9 and 1037.6 Å. Results: Plasma speeds and electron densities of the outflows were inferred over several rotations of the Sun. AR outflows are present in the newly born AR and persist throughout the entire AR life. Moreover, we found two types of outflows at different latitudes, both possibly originating in the same negative polarity area of the AR. We also analyzed the behavior of the Si xii 520 Å line along the UVCS slit in an attempt to reveal changes in the Si abundance when different regions are traversed. Although we found some evidence for a Si enrichment in the AR outflows, alternative interpretations are also plausible. Conclusions: Our results demonstrate that outflows from ARs are detectable in the intermediate corona throughout the whole AR lifetime. This confirms that outflows contribute to the slow wind.

  1. An asymmetric jet launching model for the protoplanetary nebula CRL 618

    CERN Document Server

    Velazquez, P F; Raga, A C; Toledo-Roy, J C

    2014-01-01

    We propose an asymmetrical jet ejection mechanism in order to model the mirror symmetry observed in the lobe distribution of some protoplanetary nebulae (pPNe), such as the pPN CRL 618. 3D hydrodynamical simulations of a precessing jet launched from an orbiting source were carried out including an alternation in the ejections of the two outflow lobes, depending on which side of the precessing accretion disk is hit by the accretion column from a Roche lobe-filling binary companion. Both synthetic optical emission maps and position-velocity (PV) diagrams were obtained from the numerical results with the purpose of carrying out a direct comparison with observations. Depending on the observer's point of view, multipolar morphologies are obtained which exhibit a mirror symmetry at large distances from the central source. The obtained lobe sizes and their spatial distribution are in good agreement with the observed morphology of the pPN CRL 618. We also obtain that the kinematic ages of the fingers are similar to t...

  2. On the implications of recent observations of the inner knot in the Crab nebula

    Science.gov (United States)

    Yuan, Yajie; Blandford, Roger D.

    2015-12-01

    Recent observations of the Crab nebula (Rudy et al.) have maintained its reputation for high-energy astrophysical enlightenment and its use as a test-bed for theories of the behaviour of magnetized, relativistic plasma. In particular, new observations of the inner knot located 0.65 arcsec SE from the pulsar confirm that it is compact, elongated transversely to the symmetry axis and curved concave towards the pulsar. 60 per cent polarization has been measured along the symmetry axis (Moran et al.). The knot does not appear to be involved in the gamma-ray flares. The new observations both reinforce the interpretation of the knot as dissipation of the pulsar wind at a strong shock and challenge the details of existing models of this process. In particular, it is argued that the compactness, high polarization, and curvature are difficult to reconcile with simple relativistic shock models. Alternative possibilities include deflection of the outflow ahead of the shock and spatial variation in which the knot is interpreted as a caustic. Some future observations are proposed and new theoretical investigations are suggested.

  3. On the Implications of Recent Observations of the Inner Knot in the Crab Nebula

    CERN Document Server

    Yuan, Yajie

    2015-01-01

    Recent observations of the Crab Nebula (Rudy et al 2015) have maintained its reputation for high energy astrophysical enlightenment and its use as a testbed for theories of the behaviour of magnetized, relativistic plasma. In particular, new observations of the inner knot located 0.65'' SE from the pulsar confirm that it is compact, elongated transversely to the symmetry axis and curved concave towards the pulsar. 60 percent polarization has been measured along the symmetry axis (Moran et al 2013). The knot does not appear to be involved in the gamma ray flares. The new observations both reinforce the interpretation of the knot as dissipation of the pulsar wind at a strong shock and challenge the details of existing models of this process. In particular, it is argued that the compactness, high polarization and curvature are difficult to reconcile with simple relativistic shock models. Alternative possibilities include deflection of the outflow ahead of the shock and spatial variation in which the knot is inte...

  4. A Spitzer Study of the Mass Loss Histories of Three Bipolar Pre-Planetary Nebulae

    CERN Document Server

    Do, Tuan; Sahai, Raghvendra; Stapelfeldt, Karl

    2007-01-01

    We present the results of far-infrared imaging of extended regions around three bipolar pre-planetary nebulae, AFGL 2688, OH 231.8+4.2, and IRAS 16342$-$3814, at 70 and 160 $\\mu$m with the MIPS instrument on the Spitzer Space Telescope. After a careful subtraction of the point spread function of the central star from these images, we place constraints on the existence of extended shells and thus on the mass outflow rates as a function of radial distance from these stars. We find no apparent extended emission in AFGL 2688 and OH 231.8+4.2 beyond 100 arcseconds from the central source. In the case of AFGL 2688, this result is inconsistent with a previous report of two extended dust shells made on the basis of ISO observations. We derive an upper limit of $2.1\\times10^{-7}$ M$_\\odot$ yr$^{-1}$ and $1.0\\times10^{-7}$ M$_\\odot$ yr$^{-1}$ for the dust mass loss rate of AFGL 2688 and OH 231.8, respectively, at 200 arcseconds from each source. In contrast to these two sources, IRAS 16342$-$3814 does show extended emi...

  5. Mid-infrared imaging of the bipolar planetary nebula M2-9 from SOFIA

    Energy Technology Data Exchange (ETDEWEB)

    Werner, M. W.; Sahai, R.; Davis, J.; Livingston, J. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91107 (United States); Lykou, F. [Institute for Astronomy, University of Vienna, Turkenschanzstrasse 17, A-1180, Vienna (Austria); DE Buizer, J. [USRA SOFIA Science Center, M/S 211-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Morris, M. R. [Division of Astronomy, P.O. Box 951547, UCLA, Los Angeles, CA 90095 (United States); Keller, L. [Department of Physics, Ithaca College, Ithaca, NY 14850 (United States); Adams, J.; Gull, G.; Henderson, C.; Herter, T.; Schoenwald, J., E-mail: Michael.W.Werner@jpl.nasa.gov [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States)

    2014-01-10

    We have imaged the bipolar planetary nebula M2-9 using SOFIA's FORCAST instrument in six wavelength bands between 6.6 and 37.1 μm. A bright central point source, unresolved with SOFIA's ∼4''-5'' beam, is seen at each wavelength, and the extended bipolar lobes are clearly seen at 19.7 μm and beyond. The photometry between 10 and 25 μm is well fit by the emission predicted from a stratified disk seen at large inclination, as has been proposed for this source by Lykou et al. and by Smith and Gehrz. The principal new results in this paper relate to the distribution and properties of the dust that emits the infrared radiation. In particular, a considerable fraction of this material is spread uniformly through the lobes, although the dust density does increase at the sharp outer edge seen in higher resolution optical images of M2-9. The dust grain population in the lobes shows that small (<0.1 μm) and large (>1 μm) particles appear to be present in roughly equal amounts by mass. We suggest that collisional processing within the bipolar outflow plays an important role in establishing the particle size distribution.

  6. The creation of the Helix planetary nebula (NGC 7293) by multiple events

    CERN Document Server

    Meaburn, J; López, J A; Harman, D J; Bryce, M; Redman, M P; Mavromatakis, F

    2005-01-01

    A deep, continuum-subtracted, image of NGC 7293 has been obtained in the light of the Halpha+[N II] emission lines. New images of two filamentary halo stuctures have been obtained and the possible detection of a collimated outflow made. Spatially resolved, longslit profiles of the Halpha+[N II] lines have been observed across several of these features with the MES combined with the SPM 2.1m telescope; these are compared with the [N II]6584, [O III]5007, HeII 6560 and Halpha profiles obtained over the nebular core. The central HeII emission is originating in a ~0.34pc diameter spherical volume expanding at <=12km/s which is surrounded, and partially coincident with an [O III] emitting inner shell expanding at 12km/s. The bright helical structure surrounding this inner region is modelled as a bi-polar nebula with lobe expansions of 25km/s whose axis is tilted at 37deg to the sight line but with a toroidal waist itself expanding at 14 km/s. These observations are compared with the expectations of the interact...

  7. Feedback from Mass Outflows in Nearby Active Galactic Nuclei. II. Outflows in the Narrow-Line Region of NGC 4151

    CERN Document Server

    Crenshaw, D M; Kraemer, S B; Schmitt, H R

    2014-01-01

    We present a detailed study of AGN feedback in the narrow-line region (NLR) of the Seyfert 1 galaxy NGC 4151. We illustrate the data and techniques needed to determine the mass outflow rate and kinetic luminosity of the outflowing ionized gas as a function of position in the NLR. We find that the mass outflow rate peaks at a value of 3 solar masses per year at a distance of 70 pc from the central supermassive black hole (SMBH), which is about 10 times the outflow rate coming from inside 13 pc, and 230 times the mass accretion rate inferred from the bolometric luminosity of NGC 4151. Thus, most of the outflow must arise from "in situ" acceleration of ambient gas throughout the NLR. The kinetic luminosity peaks at 90 pc and drops rapidly thereafter, indicating that most of the kinetic energy is deposited within about 100 pc from the SMBH. Both values exceed the mass outflow rate and kinetic luminosity determined for the UV/X-ray absorber outflows in NGC 4151, indicating the importance of NLR outflows in providi...

  8. [Long-term effect of polystan monocusp ventricular outflow patch after right ventricular outflow tract reconstruction].

    Science.gov (United States)

    Sugita, T; Matsumoto, M; Ogino, H; Nishizawa, J; Matsuyama, K; Yoshimura, S; Yoshioka, T; Tokuda, Y; Matsumura, M; Suda, K; Ueda, Y

    2000-09-01

    Forty-eight patients who underwent right ventricular outflow tract reconstruction with Monocusp Ventricular Outflow Patch (MVOP) fifty-five times and survived surgery, were reviewed in this study. Mean age at surgery was 6.4 years-old and mean follow-up interval was 75.2 months. There was no late death, however reoperation was performed 7 times. Freedom from reoperation rate was 97.2% and 80.7% after 5 and 10 years after surgery, respectively. The main cause for reoperation were right ventricular outflow obstruction RVOTO (5 cases). All of the RVOTO occurred at the distal end of the anastomosis. However, there was no RVOTO in patients who underwent RVOTR with MVOP during the past ten years. So, we considered the cause of RVOTO a technical problem. Pulmonary regurgitation was one to two degree early after surgery, and had worsened by almost two or three degrees more than 5 years after surgery. Moreover, five of six patients who underwent cardiac catheterization more than 10 years after surgery had three degrees of pulmonary regurgitation as well as a large CTR. In conclusion, according to long-term results, especially more than 10 years post operatively, pulmonary regurgitation was the most important problem.

  9. The Orion Nebula: Still Full of Surprises

    Science.gov (United States)

    2011-01-01

    This ethereal-looking image of the Orion Nebula was captured using the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory, Chile. This nebula is much more than just a pretty face, offering astronomers a close-up view of a massive star-forming region to help advance our understanding of stellar birth and evolution. The data used for this image were selected by Igor Chekalin (Russia), who participated in ESO's Hidden Treasures 2010 astrophotography competition. Igor's composition of the Orion Nebula was the seventh highest ranked entry in the competition, although another of Igor's images was the eventual overall winner. The Orion Nebula, also known as Messier 42, is one of the most easily recognisable and best-studied celestial objects. It is a huge complex of gas and dust where massive stars are forming and is the closest such region to the Earth. The glowing gas is so bright that it can be seen with the unaided eye and is a fascinating sight through a telescope. Despite its familiarity and closeness there is still much to learn about this stellar nursery. It was only in 2007, for instance, that the nebula was shown to be closer to us than previously thought: 1350 light-years, rather than about 1500 light-years. Astronomers have used the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile to observe the stars within Messier 42. They found that the faint red dwarfs in the star cluster associated with the glowing gas radiate much more light than had previously been thought, giving us further insights into this famous object and the stars that it hosts. The data collected for this science project, with no original intention to make a colour image, have now been reused to create the richly detailed picture of Messier 42 shown here. The image is a composite of several exposures taken through a total of five different filters. Light that passed through a red filter as well as light from a filter that

  10. Influence of ion outflow in coupled geospace simulations: 2. Sawtooth oscillations driven by physics-based ion outflow

    Science.gov (United States)

    Varney, R. H.; Wiltberger, M.; Zhang, B.; Lotko, W.; Lyon, J.

    2016-10-01

    We present the first simulations of magnetospheric sawtooth oscillations under steady solar wind conditions that are driven internally by heavy ion outflow from a physics-based model. The simulations presented use the multifluid Lyon-Fedder-Mobarry magnetohydrodynamics model two-way coupled to the ionosphere/polar wind model (IPWM). Depending on the type of wave-particle interactions utilized within IPWM, the coupled simulations exhibit either sawtooth oscillations or steady magnetospheric convection. Contrasting the simulations that do and do not develop sawtooth oscillations yields insights into the relationship between outflow and sawtooth oscillations. The total outflow rate is not an adequate predictor of the convection mode that will emerge. The simulations that develop sawtooth oscillations are characterized by intense outflow concentrated in the midnight auroral region. This outflow distribution mass loads the tail reconnection region without excessively mass loading the dayside reconnection region and leads to an imbalance between the dayside and nightside reconnection rates.

  11. n CARINAE: THE NATURE OF THE 5.54-YR CYCLE

    Directory of Open Access Journals (Sweden)

    A. Damineli

    2008-01-01

    Full Text Available Los eventos de baja excitación en eta Carinae son conocidos desde hace más de cien años, pero nunca han sido completamente caracterizados. Hemos derivado el período de aquellos, Ppres = 2022.7± 1.3 d, y mostramos que el mismo no puede haber cambiado por más de P/P = 0.0007 durante los últimos 60 a¿nos. Esto otorga una base fuerte para el escenario de binaridad. El así llamado evento de baja excitación es gobernado por el paso del periastro, cuando la estrella secundaria está profundamente inmersa en el viento de la primaria. Mostramos que los eventos en las líneas de excitación intensas están provocados por un blanketing en el campo de radiación de la estrella secundaria (la fuente ionizante. Descartamos la mayoría de los mecanismos propuestos previamente, tales como eyección del shell, colapso de la colisión viento-viento, o eclipse. Mostramos una serie de curvas de luz, ejemplificando las peculiaridades de cada rasgo, útil para planear campañas de monitoreo para el próximo mínimo, predicho a iniciarse el 11 de enero de 2009.

  12. Astrophysical Lasers Operating in optical Fe II Lines Lines in Stellar Ejecta of Eta Carinae

    CERN Document Server

    Johansson, S

    2004-01-01

    After the discovery of space masers based on OH radicals (Weaver et al, 1965) and H2O (Cheung et al, 1969) such microwave lasers have been found to work in more than 100 molecular species (Elitzur, 1992; Townes, 1997), as well as in highly excited H atoms (Strelnitski et al,1996). In the IR region (10 microns), the effect of stimulated emission of radiation in the CO2 molecule has been discovered in the Martian and Venus' atmospheres (Betz et al, 1976; Mumma et al, 1981). We report here on the discovery of laser action in the range 0.9-2 micr. in several spectral lines of Fe II, which are associated with transitions from "pseudo-metastable" states populated by spontaneous transitions from Ly-alpha pumped Fe II levels. The intense Ly-alpha radiation is formed in the HII region of gas condensations close to the star Eta Carinae. The laser transitions form together with spontaneous transitions closed radiative cycles, one of which includes the extremely bright 2507/09 A lines. Closed radiative cycles, together w...

  13. Multi-Wavelength Implications of the Companion Star in eta Carinae

    Science.gov (United States)

    Madura, Thomas I.; Gull, Theodore R.; Groh, Jose H.; Owocki, Stanley P.; Okazaki, Atsuo; Hillier, D. John; Russell, Christopher

    2012-01-01

    Eta-Carinae is considered to be a massive colliding wind binary system with a highly eccentric (e approximately 0.9), 5.54-yr orbit. However, the companion star continues to evade direct detection as the primary dwarfs its emission at most wavelengths. Using three-dimensional (3-D) SPH simulations of eta-Car's colliding winds and radiative transfer codes, we are able to compute synthetic observables across multiple wavebands for comparison to the observations. The models show that the presence of a companion star has a profound influence on the observed HST/STIS UV spectrum and H-alpha line profiles, as well as the ground-based photometric monitoring. Here, we focus on the Bore Hole effect, wherein the fast wind from the hot secondary star carves a cavity in the dense primary wind, allowing increased escape of radiation from the hotter/deeper layers of the primary's extended wind photosphere. The results have important implications for interpretations of eta-Car's observables at multiple wavelengths.

  14. Discovery of Five Candidate Analogs for $\\eta\\,$Carinae in Nearby Galaxies

    CERN Document Server

    Khan, Rubab; Stanek, K Z; Kochanek, C S; Sonneborn, G

    2015-01-01

    The late-stage evolution of very massive stars such as $\\eta\\,$Carinae may be dominated by poorly understood episodic mass ejections which may later lead to superluminous supernovae. However, as long as $\\eta\\,$Car is one of a kind, it is nearly impossible to quantitatively evaluate these possibilities. Here we announce the discovery of five objects in the nearby ($\\sim4-8\\,$Mpc) massive star-forming galaxies M$51$, M$83$, M$101$ and NGC$6946$ that have optical through mid-infrared photometric properties consistent with the hitherto unique $\\eta\\,$Car. We identified these $L_{bol}\\simeq3-8\\times10^{6}\\,L_\\odot$ objects through a systematic search of archival Spitzer and HST data. Their Spitzer mid-infrared spectral energy distributions rise steeply in the $3.6-8\\,\\mu$m bands, then turn over between $8$ and $24\\,\\mu$m, indicating the presence of warm ($\\sim400-600\\,$K) circumstellar dust. Their optical counterparts or flux limits from deep HST images are $\\sim1.5-2\\,$dex fainter than their mid-IR peaks and req...

  15. Ancient eruptions of Eta Carinae: A tale written in proper motions

    CERN Document Server

    Kiminki, Megan M; Smith, Nathan

    2016-01-01

    We analyze eight epochs of Hubble Space Telescope H$\\alpha$+[N II] imaging of Eta Carinae's outer ejecta. Proper motions of nearly 800 knots reveal that the detected ejecta are divided into three apparent age groups, dating to around 1250 A.D., to around 1550 A.D., and to during or shortly before the Great Eruption of the 1840s. Ejecta from these groups reside in different locations and provide a firm constraint that Eta Car experienced multiple major eruptions prior to the 19th century. The 1250 and 1550 events did not share the same axisymmetry as the Homunculus; the 1250 event was particularly asymmetric, even one-sided. In addition, the ejecta in the S ridge, which have been associated with the Great Eruption, appear to predate the ejection of the Homunculus by several decades. We detect essentially ballistic expansion across multiple epochs. We find no evidence for large-scale deceleration of the observed knots that could power the soft X-ray shell by plowing into surrounding material, suggesting that th...

  16. The X-ray Lightcurve of the Supermassive star eta Carinae, 1996--2014

    CERN Document Server

    Corcoran, M F; Liburd, J K; Morris, D; Gull, T R; Madura, T I; Teodoro, M; Moffat, A F J; Richardson, N D; Russell, C M P; Pollock, A M T; Owocki, S P

    2015-01-01

    Eta Carinae is the nearest example of a supermassive, superluminous, unstable star. Mass loss from the system is critical in shaping its circumstellar medium and in determining its ultimate fate. Eta Car currently loses mass via a dense, slow stellar wind and possesses one of the largest mass loss rates known. It is prone to episodes of extreme mass ejection via eruptions from some as-yet unspecified cause; the best examples of this are the large-scale eruptions which occurred in 19th century. Eta Car is a colliding wind binary in which strong variations in X-ray emission and in other wavebands are driven by the violent collision of the wind of eta Car-A and the fast, less dense wind of an otherwise hidden companion star. X-ray variations are the simplest diagnostic we have to study the wind-wind collision and allow us to measure the state of the stellar mass loss from both stars. We present the X-ray lightcurve over the last 20 years from ROSAT observations and monitoring with the Rossi X-ray Timing Explorer...

  17. The fossil wind structures of Eta Carinae: changes across on 5.54-year cycle

    CERN Document Server

    Gull, Theodore R; Teodoro, Mairan; Clementel, Nicola; Corcoran, Michael; Damineli, Augusto; Groh, Jose H; Hamaguchi, Kenji; Hiller, D John; Moffat, Anthony F J; Richardson, Noel D; Weigelt, Gerd; Lindler, Don; Feggans, Keith

    2016-01-01

    Eta Carinae, the closest, active, massive binary containing a highly unstable LBV, exhibits expanding, compressed wind shells, seen in emission, that are spatially and spectrally resolved by \\hst/\\stis. Starting in June 2009, these structures were mapped across its 5.54-year, highly elliptical, binary orbit to follow temporal changes in the light of [Fe~III] 4659\\AA\\ and [Fe~II] 4815\\AA. The emissions trace portions of fossil wind-shells, that were formed by wind-wind interactions across each cycle. Over the high-ionization state, dense arcs, photo-ionized by far ultraviolet radiation from the hot secondary, are seen in [Fe~III]. Other arcs, ionized by mid-ultraviolet radiation from the primary star, are seen in [Fe II]. The [Fe III] structures tend to be interior to [Fe II] structures that trace extensive, less disturbed primary wind. During the brief periastron passage when the secondary plunges deep into the primary's extremely dense wind, on the far side of primary star, high-ionization [Fe III] structure...

  18. Eta Carinae across the 2003.5 minimum: Spectroscopic Evidence for Massive Binary Interactions

    CERN Document Server

    Nielsen, K E; Gull, T R; Hillier, D J; Hamaguchi, K; Ivarsson, S; Lindler, D J

    2007-01-01

    We have analyzed high spatial, moderate spectral resolution observations of Eta Carinae obtained with the STIS from 1998.0 to 2004.3. The spectra show prominent P-Cygni lines in H I, Fe II and He I which are complicated by blends and contamination by nebular emission and absorption along the line-of-sight toward the observer. All lines show phase and species dependent variations in emission and absorption. For most of the cycle the He I emission is blueshifted relative to the H I and Fe II P-Cygni emission lines, which are approximately centered at system velocity. The blueshifted He I absorption varies in intensity and velocity throughout the 2024 day period. We construct radial velocity curves for the absorption component of the He I and H I lines. The He I absorption shows significant radial velocity variations throughout the cycle, with a rapid change of over 200 km/s near the 2003.5 event. The H I velocity curve is similar to that of the He I absorption, though offset in phase and reduced in amplitude. W...

  19. Discovery of CH and OH in the -513 km s-1 Ejecta of Eta Carinae

    CERN Document Server

    Verner, E; Nielsen, K E; Gull, T R; Kober, G V; Corcoran, M

    2005-01-01

    The very massive star, Eta Carinae, is enshrouded in an unusual complex of stellar ejecta, which is highly depleted in C and O, and enriched in He and N. This circumstellar gas gives rise to distinct absorption components corresponding to at least 20 different velocities along the line-of-sight. The velocity component at -513 kms-1 exhibits very low ionization with predominantly neutral species of iron-peak elements. Our statistical equilibrium/photoionization modeling indicates that the low temperature (T = 760 K) and high density (n_H=10^7 cm^-3) of the -513 kms-1 component is conducive to molecule formation including those with the elements C and O. Examination of echelle spectra obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the confirms the model's predictions. The molecules, H_2, CH, and most likely OH, have been identified in the -513 kms-1 absorption spectrum. This paper presents the analysis of the HST/STIS spectra with the deduced column densities for CH, OH and C I, and upper ...

  20. Identification of Emission Lines in the Low-Ionization Strontium Filament Near Eta Carinae

    CERN Document Server

    Hartman, H; Johansson, S; Smith, N

    2004-01-01

    We have obtained deep spectra from 1640 to 10100A with the Space Telescope Imaging Spectrograph (STIS) of the Strontium Filament, a largely neutral emission nebulosity lying close to the very luminous star Eta Carinae and showing an uncommon spectrum. Over 600 emission lines, both permitted and forbidden, have been identified. The majority originates from neutral or singly-ionized iron group elements (Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Sr is the only neutron capture element detected. The presence of Sr II, numerous strong Ti II and V II lines and the dominance of Fe I over Fe II are notable discoveries. While emission lines of hydrogen, helium, and nitrogen are associable with other spatial structures at other velocities within the Homunculus, no emission lines from these elements correspond to the spatial structure or velocity of the Sr Filament. Moreover, no identified Sr Filament emission line requires an ionization or excitation energy above approximately 8 eV. Ionized gas extends spatially along the apertur...

  1. Eta Carinae's Thermal X-ray Tail Measured with XMM-Newton and NuSTAR

    CERN Document Server

    Hamaguchi, Kenji; Gull, Theodore R; Takahashi, Hiromitsu; Grefenstette, Brian W; Yuasa, Takayuki; Stuhlinger, Martin; Russell, Christopher M P; Moffat, Anthony F J; Sharma, Neetika; Madura, Thomas I; Richardson, Noel D; Groh, Jose; Pittard, Julian M; Owocki, Stanley

    2016-01-01

    The evolved, massive highly eccentric binary system, eta Carinae, underwent a periastron passage in the summer of 2014. We obtained two coordinated X-ray observations with XMM-Newton and NuSTAR during the elevated X-ray flux state and just before the X-ray minimum flux state around this passage. These NuSTAR observations clearly detected X-ray emission associated with eta Car extending up to ~50 keV for the first time. The NuSTAR spectrum above 10 keV can be fit with the bremsstrahlung tail from a kT ~6 keV plasma. This temperature is Delta kT ~2 keV higher than those measured from the iron K emission line complex, if the shocked gas is in collisional ionization equilibrium. This result may suggest that the companion star's pre-shock wind velocity is underestimated. The NuSTAR observation near the X-ray minimum state showed a gradual decline in the X-ray emission by 40% at energies above 5 keV in a day, the largest rate of change of the X-ray flux yet observed in individual eta Car observations. The column de...

  2. Multi-Wavelength Implications of the Companion Star in Eta Carinae

    CERN Document Server

    Madura, Thomas I; Groh, Jose H; Owocki, Stanley P; Okazaki, Atsuo; Hillier, D John; Russell, Christopher

    2011-01-01

    Eta Carinae is considered to be a massive colliding wind binary system with a highly eccentric (e \\sim 0.9), 5.54-yr orbit. However, the companion star continues to evade direct detection as the primary dwarfs its emission at most wavelengths. Using three-dimensional (3-D) SPH simulations of Eta Car's colliding winds and radiative transfer codes, we are able to compute synthetic observables across multiple wavebands for comparison to the observations. The models show that the presence of a companion star has a profound influence on the observed HST/STIS UV spectrum and H-alpha line profiles, as well as the ground-based photometric monitoring. Here, we focus on the Bore Hole effect, wherein the fast wind from the hot secondary star carves a cavity in the dense primary wind, allowing increased escape of radiation from the hotter/deeper layers of the primary's extended wind photosphere. The results have important implications for interpretations of Eta Car's observables at multiple wavelengths.

  3. X-ray Emission from Eta Carinae near Periastron in 2009 I: A Two State Solution

    CERN Document Server

    Hamaguchi, Kenji; Russell, Christopher; Pollock, Andrew M T; Gull, Theodore R; Teodoro, Mairan; Madura, Thomas I; Damineli, Augusto; Pittard, Julian M

    2014-01-01

    X-ray emission from the supermassive binary system Eta Carinae declines sharply around periastron. This X-ray minimum has two distinct phases - the lowest flux phase in the first ~3 weeks and a brighter phase thereafter. In 2009, the Chandra X-ray Observatory monitored the first phase five times and found the lowest observed flux at ~1.9e-12 ergs cm-2 s-1 (3-8 keV). The spectral shape changed such that the hard band above ~4 keV dropped quickly at the beginning and the soft band flux gradually decreased to its lowest observed value in ~2 weeks. The hard band spectrum had begun to recover by that time. This spectral variation suggests that the shocked gas producing the hottest X-ray gas near the apex of the wind-wind collision (WWC) is blocked behind the dense inner wind of the primary star, which later occults slightly cooler gas downstream. Shocked gas previously produced by the system at earlier orbital phases is suggested to produce the faint residual X-ray emission seen when the emission near the apex is ...

  4. The Optical Wind Line Variability of $\\eta$ Carinae During the 2009.0 Event

    CERN Document Server

    Richardson, Noel D; Gull, Theodore R; Moffat, Anthony F J; St-Jean, Lucas

    2015-01-01

    We report on high-resolution spectroscopy of the 2009.0 spectroscopic event of $\\eta$ Carinae collected via SMARTS observations using the CTIO 1.5 m telescope and echelle spectrograph. Our observations were made almost every night over a two-month interval around the photometric minimum of $\\eta$ Car associated with the periastron passage of a hot companion. The photoionizing flux of the companion and heating related to colliding winds causes large changes in the wind properties of the massive primary star. Here we present an analysis of temporal variations in a sample of spectral lines that are clearly formed in the wind of the primary star. These lines are affected by a changing illumination of the flux of the secondary star during the periastron passage. We document the sudden onset of blue-shifted absorption that occurred in most of the lines near or slightly after periastron, and we argue that these absorption components are seen when we view the relatively undisturbed wind of the foreground primary star...

  5. 3D hydrodynamical and radiative transfer modeling of Eta Carinae's colliding winds

    CERN Document Server

    Madura, Thomas I; Gull, Theodore R; Kruip, Chael J H; Paardekooper, Jan-Pieter; Icke, Vincent

    2015-01-01

    We present results of full 3D hydrodynamical and radiative transfer simulations of the colliding stellar winds in the massive binary system Eta Carinae. We accomplish this by applying the SimpleX algorithm for 3D radiative transfer on an unstructured Voronoi-Delaunay grid to recent 3D smoothed particle hydrodynamics (SPH) simulations of the binary colliding winds. We use SimpleX to obtain detailed ionization fractions of hydrogen and helium, in 3D, at the resolution of the original SPH simulations. We investigate several computational domain sizes and Luminous Blue Variable primary star mass-loss rates. We furthermore present new methods of visualizing and interacting with output from complex 3D numerical simulations, including 3D interactive graphics and 3D printing. While we initially focus on Eta Car, the methods employed can be applied to numerous other colliding wind (WR 140, WR 137, WR 19) and dusty 'pinwheel' (WR 104, WR 98a) binary systems. Coupled with 3D hydrodynamical simulations, SimpleX simulatio...

  6. [TiII] and [NiII] emission from the strontium filament of eta Carinae

    CERN Document Server

    Bautista, M A; Gull, T R; Smith, N; Lodders, K

    2006-01-01

    We study the nature of the [TiII] and [NiII] emission from the so-called strontium filament found in the ejecta of eta Carinae. To this purpose we employ multilevel models of the TiII and NiII systems which are used to investigate the physical condition of the filament and the excitation mechanisms of the observed lines. For the TiII ion, for which no atomic data was previously available, we carry out ab initio calculations of radiative transition rates and electron impact excitation rate coefficients. It is found that the observed spectrum is consistent with the lines being excited in a mostly neutral region with an electron density of the order of $10^7$ cm$^{-3}$ and a temperature around 6000 K. In analyzing three observations with different slit orientations recorded between March~2000 and November~2001 we find line ratios that change among various observations, in a way consistent with changes of up to an order of magnitude in the strength of the continuum radiation field. These changes result from diffe...

  7. The deep OB star population in Carina from the VST Photometric H$\\alpha$ Survey (VPHAS+)

    CERN Document Server

    Mohr-Smith, M; Napiwotzki, R; Simón-Díaz, S; Wright, N J; Barentsen, G; Eislöffel, J; Farnhill, H J; Greimel, R; Monguió, M; Kalari, V; Parker, Q A; Vink, J S

    2016-01-01

    Massive OB stars are critical to the ecology of galaxies, and yet our knowledge of OB stars in the Milky Way, fainter than $V \\sim 12$, remains patchy. Data from the VST Photometric H$\\alpha$ Survey (VPHAS+) permit the construction of the first deep catalogues of blue excess-selected OB stars, without neglecting the stellar field. A total of 14900 candidates with 2MASS cross-matches are blue-selected from a 42 square-degree region in the Galactic Plane, capturing the Carina Arm over the Galactic longitude range $282^{\\circ} \\lesssim \\ell \\lesssim 293^{\\circ}$. Spectral energy distribution fitting is performed on these candidates' combined VPHAS+ $u,g,r,i$ and 2MASS $J,H,K$ magnitudes. This delivers: effective temperature constraints, statistically separating O from early-B stars; high-quality extinction parameters, $A_0$ and $R_V$ (random errors typically $ 3.5$) extinction laws are ubiquitous in the region, over the distance range 2.5--3 kpc to $\\sim$10~kpc. Near prominent massive clusters, $R_V$ tends to ri...

  8. VizieR Online Data Catalog: Deep OB star population in Carina (Mohr-Smith+, 2017)

    Science.gov (United States)

    Mohr-Smith, M.; Drew, J. E.; Napiwotzki, R.; Simon-Diaz, S.; Wright, N. J.; Barentsen, G.; Eisloeffel, J.; Farnhill, H. J.; Greimel, R.; Monguio, M.; Kalari, V.; Parker, Q. A.; Vink, J. S.

    2016-11-01

    The sky positions and photometric measurements from VPHAS+ (and 2MASS) for 14900 candidate OB stars blue-selected from the Carina region of the Galactic plane are set out in the first 24 columns. The optical magnitudes are expressed in the Vega system. These are followed by the parameters and their error estimates obtained from main-sequence fits to the optical/NIR magnitudes, along with the chi-squared measure of goodness of fit (columns 25 to 33). For the 3 degrees of freedom involved, chi-squared values up to 7.82 may be regarded as 'good fits': 5915 objects are good fits in this sense and have estimated effective temperatures high enough to place them into the O-B2 range. The fitting process delivers effective temperatures, (highly uncertain) distance moduli, and the extinction parameters, A0 and RV. Subsequent columns (34 to 37) identify which candidates are: good O-B2 fits; likely to be emission line stars (based on r-Halpha excess); candidate sub-luminous stars; candidate higher-luminosity evolved objects. The 'Notes' in column 38 provide information on cross-identifications to known objects, where these exist. Columns 39 to 49 present spectroscopically-derived parameters and associated errors for the subset of 276 stars with spectra. (1 data file).

  9. X-ray Modeling of \\eta\\ Carinae and WR140 from SPH Simulations

    CERN Document Server

    Russell, Christopher M P; Okazaki, Atsuo T; Madura, Thomas I; Owocki, Stanley P

    2011-01-01

    The colliding wind binary (CWB) systems \\eta\\ Carinae and WR140 provide unique laboratories for X-ray astrophysics. Their wind-wind collisions produce hard X-rays that have been monitored extensively by several X-ray telescopes, including RXTE. To interpret these RXTE X-ray light curves, we model the wind-wind collision using 3D smoothed particle hydrodynamics (SPH) simulations. Adiabatic simulations that account for the absorption of X-rays from an assumed point source at the apex of the wind-collision shock cone by the distorted winds can closely match the observed 2-10keV RXTE light curves of both \\eta\\ Car and WR140. This point-source model can also explain the early recovery of \\eta\\ Car's X-ray light curve from the 2009.0 minimum by a factor of 2-4 reduction in the mass loss rate of \\eta\\ Car. Our more recent models relax the point-source approximation and account for the spatially extended emission along the wind-wind interaction shock front. For WR140, the computed X-ray light curve again matches the ...

  10. Suppression of galactic outflows by cosmological infall and circumgalactic medium

    CERN Document Server

    Singh, Priyanka; Bagla, Jasjeet S; Nath, Biman B

    2016-01-01

    We investigate the relative importance of two galactic outflow suppression mechanisms : a) Cosmological infall of the intergalactic gas onto the galaxy, and b) the existence of a hot circumgalactic medium (CGM). Considering only radial motion, the infall reduces the speed of outflowing gas and even halts the outflow, depending on the mass and redshift of the galaxy. For star forming galaxies there exists an upper mass limit beyond which outflows are suppressed by the gravitational field of the galaxy. We find that infall can reduce this upper mass limit approximately by a factor of two (independent of the redshift). Massive galaxies ($\\gtrsim 10^{12} M_{\\odot}$) host large reservoir of hot, diffuse CGM around the central part of the galaxy. The CGM acts as a barrier between the infalling and outflowing gas and provides an additional source of outflow suppression. We find that at low redshifts ($z\\lesssim3.5$), the CGM is more effective than the infall in suppressing the outflows. Together, these two processes...

  11. Collective outflow from a small multiple stellar system

    CERN Document Server

    Peters, Thomas; Mac Low, Mordecai-Mark; Schrön, Martin; Federrath, Christoph; Smith, Michael D; Klessen, Ralf S

    2014-01-01

    The formation of high-mass stars is usually accompanied by powerful protostellar outflows. Such high-mass outflows are not simply scaled-up versions of their lower-mass counterparts, since observations suggest that the collimation degree degrades with stellar mass. Theoretically, the origins of massive outflows remain open to question because radiative feedback and fragmentation of the accretion flow around the most massive stars, with M > 15 M_Sun, may impede the driving of magnetic disk winds. We here present a three-dimensional simulation of the early stages of core fragmentation and massive star formation that includes a subgrid-scale model for protostellar outflows. We find that stars that form in a common accretion flow tend to have aligned outflow axes, so that the individual jets of multiple stars can combine to form a collective outflow. We compare our simulation to observations with synthetic H_2 and CO observations and find that the morphology and kinematics of such a collective outflow resembles s...

  12. Simulation of California's Major Reservoirs Outflow Using Data Mining Technique

    Science.gov (United States)

    Yang, T.; Gao, X.; Sorooshian, S.

    2014-12-01

    The reservoir's outflow is controlled by reservoir operators, which is different from the upstream inflow. The outflow is more important than the reservoir's inflow for the downstream water users. In order to simulate the complicated reservoir operation and extract the outflow decision making patterns for California's 12 major reservoirs, we build a data-driven, computer-based ("artificial intelligent") reservoir decision making tool, using decision regression and classification tree approach. This is a well-developed statistical and graphical modeling methodology in the field of data mining. A shuffled cross validation approach is also employed to extract the outflow decision making patterns and rules based on the selected decision variables (inflow amount, precipitation, timing, water type year etc.). To show the accuracy of the model, a verification study is carried out comparing the model-generated outflow decisions ("artificial intelligent" decisions) with that made by reservoir operators (human decisions). The simulation results show that the machine-generated outflow decisions are very similar to the real reservoir operators' decisions. This conclusion is based on statistical evaluations using the Nash-Sutcliffe test. The proposed model is able to detect the most influential variables and their weights when the reservoir operators make an outflow decision. While the proposed approach was firstly applied and tested on California's 12 major reservoirs, the method is universally adaptable to other reservoir systems.

  13. The role of cosmic ray pressure in accelerating galactic outflows

    CERN Document Server

    Simpson, Christine M; Marinacci, Federico; Pfrommer, Christoph; Springel, Volker; Glover, Simon C O; Clark, Paul C; Smith, Rowan J

    2016-01-01

    We study the formation of galactic outflows from supernova explosions (SNe) with the moving-mesh code AREPO in a stratified column of gas with a surface density similar to the Milky Way disk at the solar circle. We compare different simulation models for SNe placement and energy feedback, including cosmic rays (CR), and find that models that place SNe in dense gas and account for CR diffusion are able to drive outflows with similar mass loading as obtained from a random placement of SNe with no CRs. Despite this similarity, CR-driven outflows differ in several other key properties including their overall clumpiness and velocity. Moreover, the forces driving these outflows originate in different sources of pressure, with the CR diffusion model relying on non-thermal pressure gradients to create an outflow driven by internal pressure and the random-placement model depending on kinetic pressure gradients to propel a ballistic outflow. CRs therefore appear to be non-negligible physics in the formation of outflows...

  14. High-velocity molecular outflows hear massive young stellar objects

    Institute of Scientific and Technical Information of China (English)

    吴月芳; 李月兴; 杨传义; 雷成明; 孙金江; 吕静; 韩溥

    1999-01-01

    By mapping the 12CO J=1—0 lines in IRAS 05391-0217, 06114+1745 and 06291+0421, three new high-velocity bipolar molecular outflows are found. Parameters of these outflows are derived, which suggest that they are massive and energetic outflows with total kinetic energies of about 1038 J and mass loss rates about 10-5 M⊙/a. The driving sources are identified by analyzing the positions, intensities and color temperatures of the associated infrared sources. These outflows are most likely driven by single sources which correspond to massive young stellar objects. In these regions H2O masers have been detected located near the embedded infrared sources, which indicates that their exciting mechanism may be correlated with that of the CO outflows. The relationship between the parameters of outflows and central sources shows that high-velocity outflow and thermal radiation of a star are two basic correlated but different features in the evolution of young stars.

  15. The trabecular meshwork outflow pathways: structural and functional aspects.

    Science.gov (United States)

    Tamm, Ernst R

    2009-04-01

    The major drainage structures for aqueous humor (AH) are the conventional or trabecular outflow pathways, which are comprised of the trabecular meshwork (made up by the uveal and corneoscleral meshworks), the juxtacanalicular connective tissue (JCT), the endothelial lining of Schlemm's canal (SC), the collecting channels and the aqueous veins. The trabecular meshwork (TM) outflow pathways are critical in providing resistance to AH outflow and in generating intraocular pressure (IOP). Outflow resistance in the TM outflow pathways increases with age and primary open-angle glaucoma. Uveal and corneoscleral meshworks form connective tissue lamellae or beams that are covered by flat TM cells which rest on a basal lamina. TM cells in the JCT are surrounded by fibrillar elements of the extracellular matrix (ECM) to form a loose connective tissue. In contrast to the other parts of the TM, JCT cells and ECM fibrils do not form lamellae, but are arranged more irregularly. SC inner wall endothelial cells form giant vacuoles in response to AH flow, as well as intracellular and paracellular pores. In addition, minipores that are covered with a diaphragm are observed. There is considerable evidence that normal AH outflow resistance resides in the inner wall region of SC, which is formed by the JCT and SC inner wall endothelium. Modulation of TM cell tone by the action of their actomyosin system affects TM outflow resistance. In addition, the architecture of the TM outflow pathways and consequently outflow resistance appear to be modulated by contraction of ciliary muscle and scleral spur cells. The scleral spur contains axons that innervate scleral spur cells or that have the ultrastructural characteristics of mechanosensory nerve endings.

  16. ALMA OBSERVATIONS OF THE HH 46/47 MOLECULAR OUTFLOW

    Energy Technology Data Exchange (ETDEWEB)

    Arce, Hector G. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Mardones, Diego; Garay, Guido [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Corder, Stuartt A. [Joint ALMA Observatory, Av. Alonso de Cordova 3107, Vitacura, Santiago (Chile); Noriega-Crespo, Alberto [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Raga, Alejandro C. [Instituto de Ciencias Nucleares, UNAM, Ap. 70-543, 04510 D.F. (Mexico)

    2013-09-01

    The morphology, kinematics, and entrainment mechanism of the HH 46/47 molecular outflow were studied using new ALMA Cycle 0 observations. Results show that the blue and red lobes are strikingly different. We argue that these differences are partly due to contrasting ambient densities that result in different wind components having a distinct effect on the entrained gas in each lobe. A 29 point mosaic, covering the two lobes at an angular resolution of about 3'', detected outflow emission at much higher velocities than previous observations, resulting in significantly higher estimates of the outflow momentum and kinetic energy than previous studies of this source, using the CO(1-0) line. The morphology and the kinematics of the gas in the blue lobe are consistent with models of outflow entrainment by a wide-angle wind, and a simple model describes the observed structures in the position-velocity diagram and the velocity-integrated intensity maps. The red lobe exhibits a more complex structure, and there is evidence that this lobe is entrained by a wide-angle wind and a collimated episodic wind. Three major clumps along the outflow axis show velocity distribution consistent with prompt entrainment by different bow shocks formed by periodic mass ejection episodes which take place every few hundred years. Position-velocity cuts perpendicular to the outflow cavity show gradients where the velocity increases toward the outflow axis, inconsistent with outflow rotation. Additionally, we find evidence for the existence of a small outflow driven by a binary companion.

  17. Embedded Star Formation in the Eagle Nebula

    CERN Document Server

    Thompson, R I; Hester, J J; Thompson, Rodger I.; Smith, Bradford A.

    2002-01-01

    M16=NGC 6611, the Eagle Nebula, is a well studied region of star formation and the source of a widely recognized Hubble Space Telescope (HST) image. High spatial resolution infrared observations with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on HST reveal the detailed morphology of two embedded star formation regions that are heavily obscured at optical wavelengths. It is striking that only limited portions of the visually obscured areas are opaque at 2.2 microns. Although the optical images imply substantial columns of material, the infrared images show only isolated clumps of dense gas and dust. Rather than being an active factory of star production, only a few regions are capable of sustaining current star formation. Most of the volume in the columns may be molecular gas and dust, protected by capstones of dense dust. Two active regions of star formation are located at the tips of the optical northern and central large ``elephant trunk'' features shown in the WFPC2 images. They are em...

  18. Planetary Nebulae in the Small Magellanic Cloud

    CERN Document Server

    Ventura, P; Di Criscienzo, M; García-Hernández, D A; Dell'Agli, F

    2016-01-01

    We analyse the planetary nebulae (PNe) population of the Small Magellanic Cloud (SMC), based on evolutionary models of stars with metallicities in the range $10^{-3} \\leq Z \\leq 4\\times 10^{-3}$ and mass $0.9 M\\odot < M < 8M\\odot$, evolved through the asymptotic giant branch (AGB) phase. The models used account for dust formation in the circumstellar envelope. To characterise the PNe sample of the SMC, we compare the observed abundances of the various species with the final chemical composition of the AGB models: this study allows us to identify the progenitors of the PNe observed, in terms of mass and chemical composition. According to our interpretation, most of the PNe descend from low-mass ($M < 2 M\\odot$) stars, which become carbon rich, after experiencing repeated third dredge-up episodes, during the AGB phase. A fraction of the PNe showing the signature of advanced CNO processing are interpreted as the progeny of massive AGB stars, with mass above $\\sim 6 M\\odot$, undergoing strong hot bottom ...

  19. Scaled Eagle Nebula Experiments on NIF

    Energy Technology Data Exchange (ETDEWEB)

    Pound, Marc

    2017-03-28

    We performed scaled laboratory experiments at the National Ignition Facility laser to assess models for the creation of pillar structures in star-forming clouds of molecular hydrogen, in particular the famous Pillars of the Eagle Nebula. Because pillars typically point towards nearby bright ultraviolet stars, sustained directional illumination appears to be critical to pillar formation. The experiments mock up illumination from a cluster of ultraviolet-emitting stars, using a novel long duration (30--60 ns), directional, laser-driven x-ray source consisting of multiple radiation cavities illuminated in series. Our pillar models are assessed using the morphology of the Eagle Pillars observed with the Hubble Space Telescope, and measurements of column density and velocity in Eagle Pillar II obtained at the BIMA and CARMA millimeter wave facilities. In the first experiments we assess a shielding model for pillar formation. The experimental data suggest that a shielding pillar can match the observed morphology of Eagle Pillar II, and the observed Pillar II column density and velocity, if augmented by late time cometary growth.

  20. Radio Planetary Nebulae in the Magellanic Clouds

    CERN Document Server

    Filipović, M D; Reid, W A; Payne, J L; Parker, Q A; Crawford, E J; Bojičić, I S; De Horta, A Y; Hughes, A; Dickel, J; Stootman, F

    2009-01-01

    We report the extragalactic radio-continuum detection of 15 planetary nebulae (PNe) in the Magellanic Clouds (MCs) from recent Australia Telescope Compact Array+Parkes mosaic surveys. These detections were supplemented by new and high resolution radio, optical and IR observations which helped to resolve the true nature of the objects. Four of the PNe are located in the Small Magellanic Cloud (SMC) and 11 are located in the Large Magellanic Cloud (LMC). Based on Galactic PNe the expected radio flux densities at the distance of the LMC/SMC are up to ~2.5 mJy and ~2.0 mJy at 1.4 GHz, respectively. We find that one of our new radio PNe in the SMC has a flux density of 5.1 mJy at 1.4 GHz, several times higher than expected. We suggest that the most luminous radio PN in the SMC (N S68) may represent the upper limit to radio peak luminosity because it is ~3 times more luminous than NGC 7027, the most luminous known Galactic PN. We note that the optical diameters of these 15 MCs PNe vary from very small (~0.08 pc or ...

  1. The chemistry of compact planetary nebulae

    CERN Document Server

    Josselin, E

    2003-01-01

    We report high-sensitivity millimetre observations of several molecular species (13CO, HCN, HNC, CN, HCO+ and N2H+) in a sample of compact planetary nebulae. Some species such as HCO+ and CN are particularly abundant compared to envelopes around AGB stars or even interstellar clouds. We have estimated the following average values for the column densities ratios: CN/HCN~2.6, HCO+/HCN~0.5, and HNC/HCN~0.4. Thus, the chemical composition of the molecular envelopes in these compact PNe appears somewhat intermediate between the composition of proto-PNe (such as CRL 2688 or CRL 618) and well evolved PNe (such as the Ring, M4--9, or the Helix). From observations of the CO isotopomers, we have estimated that the 12C/13C ratio is in the range 10 ~< 12C/13C ~< 40. These values are below those expected from standard asymptotic giant branch models and suggest non-standard mixing processes. The observed molecular abundances are compared to very recent modelling work, and we conclude that the observations are well ex...

  2. Kn 26, a New Quadrupolar Planetary Nebula

    CERN Document Server

    Guerrero, Martin A; Ramos-Larios, Gerardo; Vazquez, Roberto

    2013-01-01

    Once classified as an emission line source, the planetary nebula (PN) nature of the source Kn 26 has been only recently recognized in digital sky surveys. To investigate the spectral properties and spatio-kinematical structure of Kn 26, we have obtained high spatial-resolution optical and near-IR narrow-band images, high-dispersion long-slit echelle spectra, and intermediate-resolution spectroscopic observations. The new data reveal an hourglass morphology typical of bipolar PNe. A detailed analysis of its morphology and kinematics discloses the presence of a second pair of bipolar lobes, making Kn 26 a new member of the subclass of quadrupolar PNe. The time-lap between the ejection of the two pairs of bipolar lobes is much smaller than their dynamical ages, implying a rapid change of the preferential direction of the central engine. The chemical composition of Kn 26 is particularly unusual among PNe, with a low N/O ratio (as of type II PNe) and a high helium abundance (as of type I PNe), although not atypica...

  3. Visual Binaries in the Orion Nebula Cluster

    CERN Document Server

    Reipurth, Bo; Connelley, Michael S; Bally, John

    2007-01-01

    We have carried out a major survey for visual binaries towards the Orion Nebula Cluster using HST images obtained with an H-alpha filter. Among 781 likely ONC members more than 60" from theta-1 Ori C, we find 78 multiple systems (75 binaries and 3 triples), of which 55 are new discoveries, in the range from 0.1" to 1.5". About 9 binaries are likely line-of-sight associations. We find a binary fraction of 8.8%+-1.1% within the limited separation range from 67.5 to 675 AU. The field binary fraction in the same range is a factor 1.5 higher. Within the range 150 AU to 675 AU we find that T Tauri associations have a factor 2.2 more binaries than the ONC. The binary separation distribution function of the ONC shows unusual structure, with a sudden steep decrease in the number of binaries as the separation increases beyond 0.5", corresponding to 225 AU. We have measured the ratio of binaries wider than 0.5" to binaries closer than 0.5" as a function of distance from the Trapezium, and find that this ratio is signifi...

  4. The inner knot of the Crab nebula

    CERN Document Server

    Lyutikov, Maxim; Porth, Oliver

    2015-01-01

    We model the inner knot of the Crab Nebula as a synchrotron emission coming from the non-spherical MHD termination shock of relativistic pulsar wind. The post-shock flow is mildly relativistic; as a result the Doppler-beaming has a strong impact on the shock appearance. The model can reproduce the knot location, size, elongation, brightness distribution, luminosity and polarization provided the effective magnetization of the section of the pulsar wind producing the knot is low, $\\sigma \\leq 1$. In the striped wind model, this implies that the striped zone is rather wide, with the magnetic inclination angle of the Crab pulsar $\\ge 45^\\circ$; this agrees with the previous model-dependent estimate based on the gamma-ray emission of the pulsar. We conclude that the tiny knot is indeed a bright spot on the surface of a quasi-stationary magnetic relativistic shock and that this shock is a site of efficient particle acceleration. On the other hand, the deduced low magnetization of the knot plasma implies that this i...

  5. The inner knot of the Crab nebula

    Science.gov (United States)

    Lyutikov, Maxim; Komissarov, Serguei S.; Porth, Oliver

    2016-02-01

    We model the inner knot of the Crab nebula as a synchrotron emission coming from the non-spherical MHD termination shock of relativistic pulsar wind. The post-shock flow is mildly relativistic; as a result the Doppler beaming has a strong impact on the shock appearance. The model can reproduce the knot location, size, elongation, brightness distribution, luminosity and polarization provided the effective magnetization of the section of the pulsar wind producing the knot is low, σ ≤ 1. In the striped wind model, this implies that the striped zone is rather wide, with the magnetic inclination angle of the Crab pulsar ≥45°; this agrees with the previous model-dependent estimate based on the gamma-ray emission of the pulsar. We conclude that the tiny knot is indeed a bright spot on the surface of a quasi-stationary magnetic relativistic shock and that this shock is a site of efficient particle acceleration. On the other hand, the deduced low magnetization of the knot plasma implies that this is an unlikely site for the Crab's gamma-ray flares, if they are related to the fast relativistic magnetic reconnection events.

  6. Planetary Nebulae and How to Observe Them

    CERN Document Server

    Griffiths, Martin

    2012-01-01

    Astronomers' Observing Guides provide up-to-date information for amateur astronomers who want to know all about what is it they are observing. This is the basis of the first part of the book. The second part details observing techniques for practical astronomers, working with a range of different instruments. Planetary Nebulae and How to Observe Them is intended for amateur astronomers who want to concentrate on one of the most beautiful classes of astronomical objects in the sky. This book will help the observer to see these celestial phenomena using telescopes of various apertures. As a Sun-like star reaches the end of its life, its hydrogen fuel starts to run out. It collapses until helium nuclei begin nuclear fusion, whereupon the star begins to pulsate, each pulsation throwing off a layer of the star's atmosphere. Eventually the atmosphere has all been ejected as an expanding cloud of gas, the star's core is exposed and ultraviolet photons cause the shell of gas to glow brilliantly - that's planetary ...

  7. H2 Temperatures in the Crab Nebula

    CERN Document Server

    Loh, E D; Ferland, G J; Curtis, Z K; Richardson, C T; Fabian, A C; Salomé, P

    2011-01-01

    We used K-band spectra to measure the H2 excitation temperatures in six molecular knots associated with the filaments in the Crab Nebula. The temperatures are quite high - in the range T ~ 2000-3000K, just below the H2 dissociation temperature. This is the temperature range over which the H2 1-0 S(1) line at 2.121\\mum has its maximum emissivity per unit mass, so there may be many additional H2 cores with lower temperatures that are too faint to detect. We also measured the electron density in adjacent ionized gas, which on the assumption of gas pressure balance indicates densities in the molecular region n_mol ~ 20,000 H baryons cm-3, although this really is just a lower limit since the H2 gas may be confined by other means. The excited region may be just a thin skin on a much more extensive blob of molecular gas that does not have the correct temperature and density to be as easily detectable. At the opposite extreme, the observed knots could consist of a fine mist of molecular gas in which we are detecting ...

  8. Modelling of asymmetric nebulae. II. Line profiles

    CERN Document Server

    Morisset, C

    2006-01-01

    We present a tool, VELNEB_3D, which can be applied to the results of 3D photoionization codes to generate emission line profiles, position-velocity maps and 3D maps in any emission line by assuming an arbitrary velocity field. We give a few examples, based on our pseudo-3D photoionization code NEBU_3D (Morisset, Stasinska and Pena, 2005) which show the potentiality and usefulness of our tool. One 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. Another example shows different ways to produce line profiles that could be attributed to a turbulent velocity field while there is no turbulence in the model. A third example shows how, in certain circumstances, it is possible to discriminate between two very different geometrical structures -- here a face-on blister and its ``spherical impostor'' -- when using appropriate high resolution spectra. Finally, we show how our tool is able to generate 3D maps, similar to the ...

  9. Outflows of neutral (and ionized) gas in radio galaxies

    OpenAIRE

    Morganti, R.; Oosterloo, T.; Tadhunter, C.

    2004-01-01

    Outflows up to 1500 km/s of atomic neutral hydrogen are detected in a growing number of radio galaxies. Outflows with similar velocities are also detected in ionized gas, suggesting a common origin for the extreme kinematics of these two phases of the gas. The high detection rate ofsuch outflows in young (or restarted) radio sources appears to be related to the existence of a dense ISM around these objects. Such a dense ISM can have important consequences for the evolution of the radio source...

  10. Misalignment of Magnetic Fields and Outflows in Protostellar Cores

    CERN Document Server

    Hull, Charles L H; Bolatto, Alberto D; Bower, Geoffrey C; Carpenter, John M; Crutcher, Richard M; Fiege, Jason D; Franzmann, Erica; Hakobian, Nicholas S; Heiles, Carl; Houde, Martin; Hughes, A Meredith; Jameson, Katherine; Kwon, Woojin; Lamb, James W; Looney, Leslie W; Matthews, Brenda C; Mundy, Lee; Pillai, Thushara; Pound, Marc W; Stephens, Ian W; Tobin, John J; Vaillancourt, John E; Volgenau, N H; Wright, Melvyn C H

    2012-01-01

    Theoretical models of star formation generally assume that bipolar outflows are parallel to the mean magnetic-field direction in protostellar cores. Here we present results of \\lambda1.3 mm dust polarization observations toward 16 nearby, low-mass protostars, mapped with ~2.5" resolution at CARMA. The results show that magnetic fields in protostellar cores on scales of ~1000 AU are not tightly aligned with outflows from the protostars. If one assumes that outflows emerge along the rotation axes of circumstellar disks, then our results imply that these disks are not aligned with the fields in the cores from which they formed.

  11. Planetary Nebulae in Face-On Spiral Galaxies. I. Planetary Nebula Photometry and Distances

    CERN Document Server

    Herrmann, Kimberly A; Feldmeier, John J; Vinciguerra, Matt

    2008-01-01

    As the first step to determine disk mass-to-light ratios for normal spiral galaxies, we present the results of an imaging survey for planetary nebulae (PNe) in six nearby, face-on systems: IC 342, M74 (NGC 628), M83 (NGC 5236), M94 (NGC 4736), NGC 5068, and NGC 6946. Using Blanco/Mosaic II and WIYN/OPTIC, we identify 165, 153, 241, 150, 19, and 71 PN candidates, respectively, and use the Planetary Nebula Luminosity Function (PNLF) to obtain distances. For M74 and NGC 5068, our distances of 8.6 +/- 0.3 Mpc and 5.4 +0.2/-0.4 Mpc are the first reliable estimates to these objects; for IC 342 (3.5 +/- 0.3 Mpc), M83 (4.8 +/- 0.1 Mpc), M94 (4.4 +0.1/-0.2 Mpc), and NGC 6946 (6.1 +/- 0.6 Mpc) our values agree well with those in the literature. In the larger systems, we find no evidence for any systematic change in the PNLF with galactic position, though we do see minor field-to-field variations in the luminosity function. In most cases, these changes do not affect the measurement of distance, but in one case the fluct...

  12. Herschel Planetary Nebula Survey (HerPlaNS) - First Detection of OH+ in Planetary Nebulae

    CERN Document Server

    Aleman, I; Ladjal, D; Exter, K M; Kastner, J H; Montez, R; Tielens, A G G M; Chu, Y H; Izumiura, H; McDonald, I; Sahai, R; Siodmiak, N; Szczerba, R; van Hoof, P A M; Villaver, E; Vlemmings, W; Wittkowski, M; Zijlstra, A A

    2014-01-01

    We report the first detections of OH+ emission in planetary nebulae (PNe). As part of an imaging and spectroscopy survey of 11 PNe in the far-IR using the PACS and SPIRE instruments aboard the Herschel Space Observatory, we performed a line survey in these PNe over the entire spectral range between 51 and 672$\\mu$m to look for new detections. OH+ rotational emission lines at 152.99, 290.20, 308.48, and 329.77$\\mu$m were detected in the spectra of three planetary nebulae: NGC 6445, NGC 6720, and NGC 6781. Excitation temperatures and column densities derived from these lines are in the range of 27 to 47 K and 2 x $10$^{10}$ to 4 x $10$^{11}$ cm$^{-2}$, respectively. In PNe, the OH+ rotational line emission appears to be produced in the photodissociation region (PDR) in these objects. The emission of OH+ is observed only in PNe with hot central stars (Teff > 100000 K), suggesting that high-energy photons may play a role in the OH+ formation and its line excitation in these objects, as it seems to be the case for...

  13. The dust content of planetary nebulae a reappraisal

    CERN Document Server

    Stasinska, G

    1999-01-01

    We have performed a statistical analysis using broad band IRAS data on about 500 planetary nebulae with the aim of characterizing their dust content. Our approach is different from previous studies in that it uses an extensive grid of photoionization models to test the methods for deriving the dust temperature, the dust-to-gas mass ratio and the average grain size. In addition, we use only distance independent diagrams. With our models, we show the effect of contamination by atomic lines in the broad band IRAS fluxes during planetary nebula evolution. We find that planetary nebulae with very different dust-to-gas mass ratios exist, so that the dust content is a primordial parameter for the interpretation of far infrared data of planetary nebulae. In contrast with previous studies, we find no evidence for a decrease in the dust-to-gas mass ratio as the planetary nebulae evolve. We also show that the decrease in grain size advocated by Natta and Panagia (1981, ApJ 248,189) and Lenzuni et al. (1989, ApJ 345, 306...

  14. Bow-shock Pulsar Wind Nebulae Passing Through Density Discontinuities

    CERN Document Server

    Yoon, Doosoo

    2016-01-01

    Bow-shock pulsar wind nebulae are a subset of pulsar wind nebulae that form when the pulsar has high velocity due to the natal kick during the supernova explosion. The interaction between the relativistic wind from the fast-moving pulsar and the interstellar medium produces a bow-shock and a trail, which are detectable in H$_{\\alpha}$ emission. Among such bow-shock pulsar wind nebulae, the Guitar Nebula stands out for its peculiar morphology, which consists of a prominent bow-shock head and a series of bubbles further behind. We present a scenario in which multiple bubbles can be produced when the pulsar encounters a series of density discontinuities in the ISM. We tested the scenario using 2-D and 3-D hydrodynamic simulations. The shape of the guitar nebula can be reproduced if the pulsar traversed a region of declining low density. We also show that if a pulsar encounters an inclined density discontinuity, it produces an asymmetric bow-shock head, consistent with observations of the bow-shock of the millise...

  15. Chandra Confirmation of a Pulsar Wind Nebula in DA 495

    Science.gov (United States)

    Arzoumanian, Z.; Safi-Harb, S.; Landecker, T.L.; Kothes, R.; Camilo, F.

    2008-01-01

    As part of a multiwavelength study of the unusual radio supernova remnant DA 495, we present observations made with the Chandra X-ray Observatory. Imaging and spectroscopic analysis confirms the previously detected X-ray source at the heart of the annular radio nebula, establishing the radiative properties of two key emission components: a soft unresolved source with a blackbody temperature of 1 MK consistent with a neutron star, surrounded by a nontherma1 nebula 40" in diameter exhibiting a power-law spectrum with photon index Gamma = 1.63, typical of a pulsar wind nebula. Morphologically, the nebula appears to be slightly extended along a direction, in projection on the sky, previously demonstrated to be of significance in radio and ASCA observations; we argue that this represents the orientation of the pulsar spin axis. At smaller scales, a narrow X-ray feature is seen extending out 5" from the point source, but energetic arguments suggest that it is not the resolved termination shock of the pulsar wind against the ambient medium. Finally, we argue based on synchrotron lifetimes in the nebular magnetic field that DA 495 represents the first example of a pulsar wind nebula in which electromagnetic flux makes up a significant part, together with particle flux, of the neutron star's wind.

  16. Optically thick outflows in ultraluminous supersoft sources

    CERN Document Server

    Urquhart, Ryan

    2015-01-01

    Ultraluminous supersoft sources (ULSs) are defined by a thermal spectrum with colour temperatures ~0.1 keV, bolometric luminosities ~ a few 10^39 erg/s, and almost no emission above 1 keV. It has never been clear how they fit into the general scheme of accreting compact objects. To address this problem, we studied a sample of seven ULSs with extensive Chandra and XMM-Newton coverage. We find an anticorrelation between fitted temperatures and radii of the thermal emitter, and no correlation between bolometric luminosity and radius or temperature. We compare the physical parameters of ULSs with those of classical supersoft sources, thought to be surface-nuclear-burning white dwarfs, and of ultraluminous X-ray sources (ULXs), thought to be super-Eddington stellar-mass black holes. We argue that ULSs are the sub-class of ULXs seen through the densest wind, perhaps an extension of the soft-ultraluminous regime. We suggest that in ULSs, the massive disk outflow becomes effectively optically thick and forms a large ...

  17. Simulating galactic outflows with kinetic supernova feedback

    CERN Document Server

    Vecchia, Claudio Dalla

    2008-01-01

    Feedback from star formation is thought to play a key role in the formation and evolution of galaxies, but its implementation in cosmological simulations is currently hampered by a lack of numerical resolution. We present and test a sub-grid recipe to model feedback from massive stars in cosmological smoothed particle hydrodynamics simulations. The energy is distributed in kinetic form among the gas particles surrounding recently formed stars. The impact of the feedback is studied using a suite of high-resolution simulations of isolated disc galaxies embedded in dark halos with total mass 10^{10} and 10^{12} M_sol/h. We focus in particular on the effect of pressure forces within the disc, which we turn off temporarily in some of our runs to mimic a recipe that has been widely used in the literature. We find that (ram) pressure forces on expanding superbubbles determine both the structure of the disc and the development of large-scale outflows. Pressure forces exerted by expanding superbubbles puff up the disc...

  18. Intergalactic Magnetic Fields from Quasar Outflows

    CERN Document Server

    Furlanetto, S; Furlanetto, Steven; Loeb, Abraham

    2001-01-01

    Outflows from quasars inevitably pollute the intergalactic medium (IGM) with magnetic fields. The short-lived activity of a quasar leaves behind an expanding magnetized bubble in the IGM. We model the expansion of the remnant quasar bubbles and calculate their distribution as a function of size and magnetic field strength at different redshifts. We generically find that by a redshift z=3, about 5-20% of the IGM volume is filled by magnetic fields with an energy density >10% of the mean thermal energy density of a photo-ionized IGM (at T=10^4 K). As massive galaxies and X-ray clusters condense out of the magnetized IGM, the adiabatic compression of the magnetic field could result in the field strength observed in these systems without a need for further dynamo amplification. The intergalactic magnetic field could also provide a nonthermal contribution to the pressure of the photo-ionized gas that may account for the claimed discrepancy between the simulated and observed Doppler width distributions of the Ly-al...

  19. Radiation Transport for Explosive Outflows: Opacity Regrouping

    CERN Document Server

    Wollaeger, Ryan T

    2014-01-01

    Implicit Monte Carlo (IMC) and Discrete Diffusion Monte Carlo (DDMC) are methods used to stochastically solve the radiative transport and diffusion equations, respectively. These methods combine into a hybrid transport-diffusion method we refer to as IMC-DDMC. We explore a multigroup IMC-DDMC scheme that, in DDMC, combines frequency groups with sufficient optical thickness. We term this procedure "opacity regrouping". Opacity regrouping has previously been applied to IMC-DDMC calculations for problems in which the dependence of the opacity on frequency is monotonic. We generalize opacity regrouping to non-contiguous groups and implement this in \\supernu, a code designed to do radiation transport in high-velocity outflows with non-monotonic opacities. We find that regrouping of non-contiguous opacity groups generally improves the speed of IMC-DDMC radiation transport. We present an asymptotic analysis that informs the nature of the Doppler shift in DDMC groups and summarize the derivation of the Gentile-Fleck ...

  20. A new Planetary Nebula in the outer reaches of the Galaxy

    DEFF Research Database (Denmark)

    Viironen, K.; Mampaso, A.; L. M. Corradi, R.;

    2011-01-01

    of a new planetary nebula towards the Anticentre direction, IPHASX J052531.19+281945.1 (PNG 178.1-04.0), is presented. The planetary nebula was discovered from the IPHAS survey. Long-slit follow-up spectroscopy was carried out to confirm its planetary nebula nature and to calculate its physical...