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Sample records for jet ii x-ray

  1. Chandra Reveals Twin X-ray Jets in the Powerful FR II Radio Galaxy 3C 353

    SciTech Connect

    Kataoka, Jun

    2008-12-24

    We report X-ray imaging of the powerful FR II radio galaxy 3C 353 using the Chandra X-ray Observatory. 3C 353's two 4''-wide and 2'-long jets allow us to study in detail the internal structure of the large-scale relativistic outflows at both radio and X-ray photon energies with the sub-arcsecond spatial resolution provided by the VLA and Chandra instruments. In a 90 ks Chandra observation, we have detected X-ray emission from most radio structures in 3C 353, including the nucleus, the jet and the counterjet, the terminal jet regions (hotspots), and one radio lobe. We show that the detection of the X-ray emission associated with the radio knots and counterknots, which is most likely non-thermal in origin, puts several crucial constraints on the X-ray emission mechanisms in powerful large-scale jets of quasars and FR II sources. In particular, we show that this detection is inconsistent with the inverse-Compton model proposed in the literature, and instead implies a synchrotron origin of the X-ray jet photons. We also find that the width of the X-ray counterjet is possibly narrower than that measured in radio bands, that the radio-to-X-ray flux ratio decreases systematically downstream along the jets, and that there are substantial (kpc-scale) offsets between the positions of the X-ray and radio intensity maxima within each knot, whose magnitudes increase away from the nucleus. We discuss all these findings in the wider context of the physics of extragalactic jets, proposing some particular though not definitive solutions or interpretations for each problem. In general, we find that the synchrotron X-ray emission of extragalactic large-scale jets is not only shaped by the global hydrodynamical configuration of the outflows, but is also likely to be very sensitive to the microscopic parameters of the jet plasma. A complete, self-consistent model for the X-ray emission of extragalactic jets still remains elusive.

  2. Chandra Reveals Twin X-ray Jets in the Powerful FR-II Radio Galaxy 3C353

    SciTech Connect

    Kataoka, J.; Stawarz, L.; Harris, D.E.; Siemiginowska, A.; Ostrowski, M.; Swain, M.R.; Hardcastle, M.J.; Goodger, J.L.; Iwasawa, K.; Edwards, P.G.

    2008-06-13

    We report X-ray imaging of the powerful FR II radio galaxy 3C 353 using the Chandra X-ray Observatory. 3C 353's two 4-inch wide and 2-feet long jets allow us to study in detail the internal structure of the large-scale relativistic outflows at both radio and X-ray photon energies with the sub-arcsecond spatial resolution provided by the VLA and Chandra instruments. In a 90 ks Chandra observation, we have detected X-ray emission from most radio structures in 3C 353, including the nucleus, the jet and the counterjet, the terminal jet regions (hotspots), and one radio lobe. We show that the detection of the X-ray emission associated with the radio knots and counterknots, which is most likely non-thermal in origin, puts several crucial constraints on the X-ray emission mechanisms in powerful large-scale jets of quasars and FR II sources. In particular, we show that this detection is inconsistent with the inverse-Compton model proposed in the literature, and instead implies a synchrotron origin of the X-ray jet photons. We also find that the width of the X-ray counterjet is possibly narrower than that measured in radio bands, that the radio-to-X-ray flux ratio decreases systematically downstream along the jets, and that there are substantial (kpc-scale) offsets between the positions of the X-ray and radio intensity maxima within each knot, whose magnitudes increase away from the nucleus. We discuss all these findings in the wider context of the physics of extragalactic jets, proposing some particular though not definitive solutions or interpretations for each problem. In general, we find that the synchrotron X-ray emission of extragalactic large-scale jets is not only shaped by the global hydrodynamical configuration of the outflows, but is also likely to be very sensitive to the microscopic parameters of the jet plasma. A complete, self-consistent model for the X-ray emission of extragalactic jets still remains elusive.

  3. SOLAR X-RAY JETS, TYPE-II SPICULES, GRANULE-SIZE EMERGING BIPOLES, AND THE GENESIS OF THE HELIOSPHERE

    SciTech Connect

    Moore, Ronald L.; Sterling, Alphonse C.; Cirtain, Jonathan W.; Falconer, David A.

    2011-04-10

    From Hinode observations of solar X-ray jets, Type-II spicules, and granule-size emerging bipolar magnetic fields in quiet regions and coronal holes, we advocate a scenario for powering coronal heating and the solar wind. In this scenario, Type-II spicules and Alfven waves are generated by the granule-size emerging bipoles (EBs) in the manner of the generation of X-ray jets by larger magnetic bipoles. From observations and this scenario, we estimate that Type-II spicules and their co-generated Alfven waves carry into the corona an area-average flux of mechanical energy of {approx}7 x 10{sup 5} erg cm{sup -2} s{sup -1}. This is enough to power the corona and solar wind in quiet regions and coronal holes, and therefore indicates that the granule-size EBs are the main engines that generate and sustain the entire heliosphere.

  4. AGN jet power, formation of X-ray cavities, and FR I/II dichotomy in galaxy clusters

    NASA Astrophysics Data System (ADS)

    Fujita, Yutaka; Kawakatu, Nozomu; Shlosman, Isaac

    2016-04-01

    We investigate the ability of jets in active galactic nuclei to break out of the ambient gas with sufficiently large advance velocities. Using observationally estimated jet power, we analyze 28 bright elliptical galaxies in nearby galaxy clusters. Because the gas density profiles in the innermost regions of galaxies have not been resolved so far, we consider two extreme cases for temperature and density profiles. We also follow two types of evolution for the jet cocoons: being driven by the pressure inside the cocoon [Fanaroff-Riley (FR) type I], and being driven by the jet momentum (FR type II). Our main result is that regardless of the assumed form of the density profiles, jets with observed powers of ≲1044 erg s-1 are not powerful enough to evolve as FR II sources. Instead, they evolve as FR I sources and appear to be decelerated below the buoyant velocities of the cocoons when jets were propagating through the central dense regions of the host galaxies. This explains why FR I sources are more frequent than FR II sources in clusters. Furthermore, we predict the sizes of X-ray cavities from the observed jet powers and compare them with the observed ones-they are consistent within a factor of two if the FR I type evolution is realized. Finally, we find that the jets with a power ≳1044 erg s-1 are less affected by the ambient medium, and some of them, but not all, could serve as precursors of the FR II sources.

  5. Magnetic Untwisting in Most Solar X-Ray Jets

    NASA Astrophysics Data System (ADS)

    Moore, Ronald L.; Sterling, A. C.; Falconer, D.; Robe, D. M.

    2013-07-01

    From 54 X-ray jets observed in the polar coronal holes by Hinode’s X-Ray Telescope (XRT) during coverage in movies from Solar Dynamic Observatory’s Atmospheric Imaging Assembly (AIA) taken in its He II 304 Å band at a cadence of 12 s, we have established a basic characteristic of solar X-ray jets: untwisting motion in the spire. In this presentation, we show the progression of few of these X-ray jets in XRT images and track their untwisting in AIA He II images. From their structure displayed in their XRT movies, 19 jets were evidently standard jets made by interchange reconnection of the magnetic-arcade base with ambient open field, 32 were evidently blowout jets made by blowout eruption of the base arcade, and 3 were of ambiguous form. As was anticipated from the >10,000 km span of the base arcade in most polar X-ray jets and from the disparity of standard jets and blowout jets in their magnetic production, few of the standard X-ray jets (3 of 19) but nearly all of the blowout X-ray jets (29 of 32) carried enough cool (T ~ 10^5 K) plasma to be seen in their He II movies. In the 32 X-ray jets that showed a cool component, the He II movies show 10-100 km/s untwisting motions about the axis of the spire in all 3 standard jets and in 26 of the 29 blowout jets. Evidently, the open magnetic field in nearly all blowout X-ray jets and probably in most standard X-ray jets carries transient twist. This twist apparently relaxes by propagating out along the open field as a torsional wave. High-resolution spectrograms and Dopplergrams have shown that most Type-II spicules have torsional motions of 10-30 km/s. Our observation of similar torsional motion in X-ray jets (1) strengthens the case for Type-II spicules being made in the same way as X-ray jets, by blowout eruption of a twisted magnetic arcade in the spicule base and/or by interchange reconnection of the twisted base arcade with the ambient open field, and hence (2) strengthens the case made by Moore et al (2011

  6. Magnetic Untwisting in Most Solar X-Ray Jets

    NASA Technical Reports Server (NTRS)

    Moore, Ronald; Sterling, Alphonse; Falconer, David; Robe, Dominic

    2013-01-01

    From 54 X-ray jets observed in the polar coronal holes by Hinode's X-Ray Telescope (XRT) during coverage in movies from Solar Dynamic Observatory's Atmospheric Imaging Assembly (AIA) taken in its He II 304 Å band at a cadence of 12 s, we have established a basic characteristic of solar X-ray jets: untwisting motion in the spire. In this presentation, we show the progression of few of these X-ray jets in XRT images and track their untwisting in AIA He II images. From their structure displayed in their XRT movies, 19 jets were evidently standard jets made by interchange reconnection of the magnetic-arcade base with ambient open field, 32 were evidently blowout jets made by blowout eruption of the base arcade, and 3 were of ambiguous form. As was anticipated from the >10,000 km span of the base arcade in most polar X-ray jets and from the disparity of standard jets and blowout jets in their magnetic production, few of the standard X-ray jets (3 of 19) but nearly all of the blowout X-ray jets (29 of 32) carried enough cool (T is approximately 105 K) plasma to be seen in their He II movies. In the 32 X-ray jets that showed a cool component, the He II movies show 10-100 km/s untwisting motions about the axis of the spire in all 3 standard jets and in 26 of the 29 blowout jets. Evidently, the open magnetic field in nearly all blowout X-ray jets and probably in most standard X-ray jets carries transient twist. This twist apparently relaxes by propagating out along the open field as a torsional wave. High-resolution spectrograms and Dopplergrams have shown that most Type-II spicules have torsional motions of 10-30 km/s. Our observation of similar torsional motion in X-ray jets strengthens the case for Type-II spicules being made in the same way as X-ray jets, by blowout eruption of a twisted magnetic arcade in the spicule base and/or by interchange reconnection of the twisted base arcade with the ambient open field. This work was funded by NASA's Heliophysics Division

  7. Complete multiwavelength evolution of galactic black hole transients during outburst decay. II. Compact jets and X-ray variability properties

    SciTech Connect

    Dinçer, T.; Kalemci, E.; Tomsick, J. A.; Buxton, M. M.; Bailyn, C. D.

    2014-11-01

    We investigated the relation between compact jet emission and X-ray variability properties of all black hole transients with multiwavelength coverage during their outburst decays. We studied the evolution of all power spectral components (including low-frequency quasi-periodic oscillations; QPOs), and related this evolution to changes in jet properties tracked by radio and infrared observations. We grouped sources according to their tracks in the radio/X-ray luminosity relation and show that the standards show stronger broadband X-ray variability than outliers at a given X-ray luminosity when the compact jet turns on. This trend is consistent with the internal shock model and can be important for the understanding of the presence of tracks in the radio/X-ray luminosity relation. We also observed that the total and the QPO rms amplitudes increase together during the earlier part of the outburst decay, but after the compact jet turns, either the QPO disappears or its rms amplitude decreases significantly while the total rms amplitudes remain high. We discuss these results with a scenario including a variable corona and a non-variable disk with a mechanism for the QPO separate from the mechanism that creates broad components. Finally, we evaluated the timing predictions of the magnetically dominated accretion flow model that can explain the presence of tracks in the radio/X-ray luminosity relation.

  8. Dichotomy of X-Ray Jets in Solar Coronal Holes

    NASA Astrophysics Data System (ADS)

    Robe, D. M.; Moore, R. L.; Falconer, D. A.

    2012-12-01

    It has been found that there are two different types of X-ray jets observed in the Sun's polar coronal holes: standard jets and blowout jets. A proposed model of this dichotomy is that a standard jet is produced by a burst of reconnection of the ambient magnetic field with the opposite-polarity leg of the base arcade. In contrast, it appears that a blowout jet is produced when the interior of the arcade has so much pent-up free magnetic energy in the form of shear and twist in the interior field that the external reconnection unleashes the interior field to erupt open. In this project, X-ray movies of the polar coronal holes taken by Hinode were searched for X-ray jets. Co-temporal movies taken by the Solar Dynamics Observatory in 304 Å emission from He II, showing solar plasma at temperatures around 80,000 K, were examined for whether the identified blowout jets carry much more He II plasma than the identified standard jets. It was found that though some jets identified as standard from the X-ray movies could be seen in the He II 304 Å movies, the blowout jets carried much more 80,000 K plasma than did most standard jets. This finding supports the proposed model for the morphology and development of the two types of jets.

  9. The cool component and the dichotomy, lateral expansion, and axial rotation of solar X-ray jets

    SciTech Connect

    Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.; Robe, Dominic

    2013-06-01

    We present results from a study of 54 polar X-ray jets that were observed in coronal X-ray movies from the X-ray Telescope on Hinode and had simultaneous coverage in movies of the cooler transition region (T ∼ 10{sup 5} K) taken in the He II 304 Å band of the Atmospheric Imaging Assembly (AIA) on Solar Dynamics Observatory. These dual observations verify the standard-jet/blowout-jet dichotomy of polar X-ray jets previously found primarily from XRT movies alone. In accord with models of blowout jets and standard jets, the AIA 304 Å movies show a cool (T ∼ 10{sup 5} K) component in nearly all blowout X-ray jets and in a small minority of standard X-ray jets, obvious lateral expansion in blowout X-ray jets but none in standard X-ray jets, and obvious axial rotation in both blowout X-ray jets and standard X-ray jets. In our sample, the number of turns of axial rotation in the cool-component standard X-ray jets is typical of that in the blowout X-ray jets, suggesting that the closed bipolar magnetic field in the jet base has substantial twist not only in all blowout X-ray jets but also in many standard X-ray jets. We point out that our results for the dichotomy, lateral expansion, and axial rotation of X-ray jets add credence to published speculation that type-II spicules are miniature analogs of X-ray jets, are generated by granule-size emerging bipoles, and thereby carry enough energy to power the corona and solar wind.

  10. Statistical study of the polar X-ray jets

    NASA Astrophysics Data System (ADS)

    Sako, Nobuharu; Shimojo, Masumi; Kitabayashi, Teruyuki

    The X-Ray Telescope(XRT) abroad Hinode had revealed that X-ray jets in the polar region occur at the high frequency. Savcheva et al. (2007) studied 104 X-ray jets occurred around the south pole and reported the parameters of the jets. However, their study included only the X-ray jets that occurred in the coronal hole. In order to reveal the properties of the polar X-ray jets in not only the coronal hole but also the quiet region, we detected 870 polar X-ray jets occurred around the north pole, and investigated the jets statistically. The 470 jets in the 848 events occurred in the coronal hole. The occurrence rate of the jets in the coronal hole and the quiet sun is 5.04×10-12 jets/hr/km2 and 7.66×10-12 jets/hr/km2 , respectively. It shows that the quiet region is more productive of X-ray jets than the coronal hole. We derived five parameters of the polar X-ray jets, and the average of the parameters are 2.91×104 km for the maximum length, 4.42×103 km for the width, and 180 km/sec for the apparent velocity. The lifetime and length scale of the jets in this result is smaller than that in Savcheva et al. (2007). The reason for these differences is that we could detect smaller jets than the previous work because we used not only X-ray intensity images but also the running difference images for detecting the jets. We derived also the frequency distributions of the parameters and found thatthe frequency distributions of the lifetime and the X-ray intensity of the footpoint flare show the power-raw distribution. The power-law index of the lifetime is -4.22±0.36, and it is smaller than the index(-1.2) derived from the jets that occurred near the active regions(Shimojo et al. 1996). The difference indicates that the occurrence rate of the polar X-ray jets with short lifetime is larger than that of the X-ray jets that occurred near active regions.On the other hand, the power-raw index of the X-ray intensity of the footpoint flare is -2.04±0.27. The index is smaller

  11. Chandra enables study of x-ray jets

    PubMed Central

    Schwartz, Daniel

    2010-01-01

    The exquisite angular resolution of the Chandra x-ray telescope has enabled the detection and study of resolved x-ray jets in a wide variety of astronomical systems. Chandra has detected extended jets in our galaxy from protostars, symbiotic binaries, neutron star pulsars, black hole binaries, extragalactic jets in radio sources, and quasars. The x-ray data play an essential role in deducing the emission mechanism of the jets, in revealing the interaction of jets with the intergalactic or intracluster media, and in studying the energy generation budget of black holes. PMID:20378839

  12. Chandra enables study of x-ray jets.

    PubMed

    Schwartz, Daniel

    2010-04-20

    The exquisite angular resolution of the Chandra x-ray telescope has enabled the detection and study of resolved x-ray jets in a wide variety of astronomical systems. Chandra has detected extended jets in our galaxy from protostars, symbiotic binaries, neutron star pulsars, black hole binaries, extragalactic jets in radio sources, and quasars. The x-ray data play an essential role in deducing the emission mechanism of the jets, in revealing the interaction of jets with the intergalactic or intracluster media, and in studying the energy generation budget of black holes. PMID:20378839

  13. X-Ray Emission from Protostellar Jets

    NASA Technical Reports Server (NTRS)

    Morse, Jon A.; McCray, Dick; Bally, John; Devine, David

    1998-01-01

    The goals of this program were to identify the termination shocks in several parsec-scale protostellar jets through the thermal soft X-rays emitted by the high-velocity terminal shock waves, and to assess the impact these outflows have on the surrounding interstellar and intercloud medium. The terminal shock waves that plow into the undisturbed interstellar medium may have shock velocities commensurate with the observed space motions of several hundred km s(exp -1). Such shocks will heat and ionize the interstellar medium, perhaps creating large ovoid bubbles of hot gas. Identifying the location of the terminal shocks in these outflows would also allow us to place constraints on the ages of these outflows, and hence the duration of the mass-loss phase that accompanies the formation of a star. We targeted four outflows where the outer optical shock waves are projected against low-extinction backgrounds. From the two dozen or so parsec-scale flows known, we chose those that have the highest velocities, brightest optical counterparts, and/or the richest concentration of shock waves in a small area on the sky. Four giant HH flows have been observed with the ROSAT HRI at Priority A for 30 ksec each. Results: Unfortunately, we failed to detect X-ray emission from the terminal bow shocks of the giant HH flows using the ROSAT HRI. The reasons are likely to be: (1) The shock velocities may be too low to emit in the soft X-rays. (2) The sensitivity of the HRI is too low to detect the diffuse emission. The fields that we observed were chosen to be low extinction sight-lines, with the consequence that the tenuous media into which the outer bow shocks are propagating produce low fluxes. Despite the failure to achieve the primary science goals, we have identified in each image a half a dozen or so point-source young stellar objects. The HRI images have been very useful for discerning potential outflow sources and are being combined with optical, near-IR, and radio imaging data

  14. Surprise Discovery of an X-Ray Jet

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-02-01

    Accreting, supermassive black holes that reside at galactic centers can power enormous jets, bright enough to be observed from vast distances away. The recent discovery of such a jet in X-ray wavelengths, without an apparent radio counterpart, has interesting implications for our understanding of how these distant behemoths shine.An Excess of X-RaysQuasar B3 0727+409 was serendipitously discovered to host an X-ray jet when a group of scientists, led by Aurora Simionescu (Institute of Space and Astronautical Sciences of the Japan Aerospace Exploration Agency), was examining Chandra observations of another object.The Chandra data reveal bright, compact, extended emission from the core of quasar B3 0727+409, with a projected length of ~100 kpc. There also appears to be further X-ray emission at a distance of ~280 kpc, which Simionescu and collaborators speculate may be the terminal hotspot of the jet.The quasar is located at a redshift of z=2.5 which makes this jet one of only a few high-redshift X-ray jets known to date. But what makes it especially intriguing is that, though the authors searched through both recent and archival radio observations of the quasar, the only radio counterpart they could find was a small feature close to the quasar core (which may be a knot in the jet). Unlike what is typical of quasar jets, there was no significant additional radio emission coinciding with the rest of the X-ray jet.Making Jets ShineX-ray-to-radio flux ratio vs. redshift, for X-ray quasar jets detected with Chandra. B3 0727+409 is shown in red (with and without the radio knot). The curves represent inverse-Compton scattering models with different magnetic field strengths. [Simionescu et al. 2016]What does this mean? To answer this, we must consider one of the outstanding questions about quasar jets: what radiation processes dominate their emission? One process possibly contributing to the X-ray emission is inverse-Compton scattering of low-energy cosmic microwave

  15. DISCOVERY OF AN EXTENDED X-RAY JET IN AP LIBRAE

    SciTech Connect

    Kaufmann, S.; Wagner, S. J.; Tibolla, O.

    2013-10-20

    Chandra observations of the low-energy-peaked BL Lac object (LBL) AP Librae (AP Lib) revealed the clear discovery of a non-thermal X-ray jet. AP Lib is the first LBL with an extended non-thermal X-ray jet that shows emission into the very high energy range. The X-ray jet has an extension of ∼15''(≈ 14 kpc). The X-ray jet morphology is similar to the radio jet observed with Very Large Array at 1.36 GHz emerging in the southeast direction and bends by 50° at a distance of 12'' toward the northeast. The intensity profiles of the X-ray emission studied are consistent with those found in the radio range. The spectral analysis reveals that the X-ray spectra of the core and jet region are both inverse-Compton-(IC)-dominated. This adds to a still small sample of BL Lac objects whose X-ray jets are IC-dominated and thus more similar to the high-luminosity Fanaroff-Riley II sources than to the low-luminosity Fanaroff-Riley I objects, which are usually considered to be the parent population of BL Lac objects.

  16. The Classification of Extragalactic X-ray Jets

    NASA Astrophysics Data System (ADS)

    Harris, D. E.; Massaro, F.; Cheung, C. C.

    2010-07-01

    The overall classification of X-ray jets has clung to that prevalent in the radio: FRI vs. FRO (including quasars). Indeed, the common perception is that X-ray emission from FRI's is synchrotron emission whereas that from FRII's may be IC/CMB and/or synchrotron. Now that we have a sizable collection of sources with detected X-ray emission from jets and hotspots, it seems that a more unbiased study of these objects could yield additional insights on jets and their X-ray emission. The current contribution is a first step in the process of analyzing all of the relevant parameters for each detected component for the sources collected in the XJET website. This initial effort involves measuring the ratio of X-ray to radio fluxes and evaluating correlations with other jet parameters. For single zone synchrotron X-ray emission, we anticipate that larger values of fx/fr should correlate inversely with the average magnetic field strength (if the acceleration process is limited by loss time equals acceleration time). Beamed IC/CMB X-rays should produce larger values of fx/fr for smaller values of the angle between the jet direction and the line of sight but will also be affected by the low frequency radio spectral index.

  17. Jets and Accretion Disks in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Tomsick, John

    The outflow of material in the form of jets is a common phenomenon in astronomical sources with accretion disks. Even though jets are seen coming from the cores of galaxies, Galactic compact objects in X-ray binaries, and stars as they are forming, we do not understand in detail what accretion disk conditions are necessary to support a relativistic jet. This proposal focuses on multi-wavelength studies of X-ray binaries in order to improve our understanding of the connection between the disk and the jet. Specifically, this proposal includes work on two approved cycle 14 Rossi X-ray Timing Explorer (RXTE) programs, an approved XMM-Newton program, as well as a synthesis study of transient black hole X-ray binaries using archival RXTE and radio data. We plan to use X-ray spectral and timing properties to determine the disk properties during the re-activation of the compact jet (as seen in the radio and infrared) during the decays of black hole transient outbursts, to determine how the inner disk properties change at low mass accretion rates, and to use RXTE along with multi-wavelength observations to constrain the jet properties required for the microquasar Cygnus~X-3 to produce high- energy emission. Due to the ubiquity of jets in astrophysical settings, these science topics are relevant to NASA programs dealing with the origin, structure, evolution, and destiny of the Universe, and especially to understanding phenomena near black holes.

  18. The Spectacular Radio-near-IR-X-Ray Jet of 3C 111: The X-Ray Emission Mechanism and Jet Kinematics

    NASA Astrophysics Data System (ADS)

    Clautice, Devon; Perlman, Eric S.; Georganopoulos, Markos; Lister, Matthew L.; Tombesi, Francesco; Cara, Mihai; Marshall, Herman L.; Hogan, Brandon; Kazanas, Demos

    2016-08-01

    Relativistic jets are the most energetic manifestation of the active galactic nucleus (AGN) phenomenon. AGN jets are observed from the radio through gamma-rays and carry copious amounts of matter and energy from the sub-parsec central regions out to the kiloparsec and often megaparsec scale galaxy and cluster environs. While most spatially resolved jets are seen in the radio, an increasing number have been discovered to emit in the optical/near-IR and/or X-ray bands. Here we discuss a spectacular example of this class, the 3C 111 jet, housed in one of the nearest, double-lobed FR II radio galaxies known. We discuss new, deep Chandra and Hubble Space Telescope (HST) observations that reveal both near-IR and X-ray emission from several components of the 3C 111 jet, as well as both the northern and southern hotspots. Important differences are seen between the morphologies in the radio, X-ray, and near-IR bands. The long (over 100 kpc on each side), straight nature of this jet makes it an excellent prototype for future, deep observations, as it is one of the longest such features seen in the radio, near-IR/optical, and X-ray bands. Several independent lines of evidence, including the X-ray and broadband spectral shape as well as the implied velocity of the approaching hotspot, lead us to strongly disfavor the EC/CMB model and instead favor a two-component synchrotron model to explain the observed X-ray emission for several jet components. Future observations with NuSTAR, HST, and Chandra will allow us to further constrain the emission mechanisms.

  19. Formation and Destruction of Jets in X-ray Binaries

    NASA Technical Reports Server (NTRS)

    Kylafix, N. D.; Contopoulos, I.; Kazanas, D.; Christodoulou, D. M.

    2011-01-01

    Context. Neutron-star and black-hole X-ray binaries (XRBs) exhibit radio jets, whose properties depend on the X-ray spectral state e.nd history of the source. In particular, black-hole XRBs emit compact, 8teady radio jets when they are in the so-called hard state. These jets become eruptive as the sources move toward the soft state, disappear in the soft state, and then re-appear when the sources return to the hard state. The jets from neutron-star X-ray binaries are typically weaker radio emitters than the black-hole ones at the same X-ray luminosity and in some cases radio emission is detected in the soft state. Aims. Significant phenomenology has been developed to describe the spectral states of neutron-star and black-hole XRBs, and there is general agreement about the type of the accretion disk around the compact object in the various spectral states. We investigate whether the phenomenology describing the X-ray emission on one hand and the jet appearance and disappearance on the other can be put together in a consistent physical picture. Methods. We consider the so-called Poynting-Robertson cosmic battery (PRCB), which has been shown to explain in a natural way the formation of magnetic fields in the disks of AGNs and the ejection of jets. We investigate whether the PRCB can also explain the [ormation, destruction, and variability or jets in XRBs. Results. We find excellent agreement between the conditions under which the PRCB is efficient (i.e., the type of the accretion disk) and the emission or destruction of the r.adio jet. Conclusions. The disk-jet connection in XRBs can be explained in a natural way using the PRCB.

  20. The Relationship Between X-Rays and Relativistic Jets

    NASA Technical Reports Server (NTRS)

    Marscher, A. P.; Jorstad, S. G.; McHardy, I. M.; Aller, M. F.; Balonek, T. J.; Villata, M.; Raiteri, C. M.; Ostorero, L.; Tosti, G.; Terasranta, H.

    2002-01-01

    We present recent multiwaveband observations centered on X-ray monitoring of blazars and the radio galaxy 3C 120 with the RXTE satellite, In 3C 120, we observed four X-ray dips, each followed by ejections of superluminal radio knots down the jet. This behavior, similar to that of the microquasar GRS 1915+105, is interpreted as infall of a piece of the inner accretion disk causing ejection of energy into the relativistic jet. The X-ray emission from the quasars PKS 1510-089, 3C 279, and 3C 273 is highly variable on timescales as short as approximately 1 day. Over 2 years, X-ray flares in PKS 1510-089 occurred about 2 weeks after radio outbursts, which can be explained by light-travel delays. In 3C 279 the X-ray and optical variations are usually well correlated, with very little, if any, time delay. We conclude that the X-ray and optical emission from blazars occurs near the radio core rather than close to the black hole.

  1. Revised View of Solar X-Ray Jets

    NASA Astrophysics Data System (ADS)

    Sterling, A. C.; Moore, R. L.; Falconer, D. A.; Adams, M.

    2015-12-01

    We investigate the onset of ~20 random X-ray jets observed by Hinode/XRT. Each jetwas near the limb in a polar coronal hole, and showed a ''bright point'' in anedge of the base of the jet, as is typical for previously-observed X-ray jets. Weexamined SDO/AIA EUV images of each of the jets over multiple AIA channels,including 304 Ang, which detects chromospheric emissions, and 171, 193, and 211 Ang,which detect cooler-coronal emissions. We find the jets to result from eruptionsof miniature (size <~10 arcsec) filaments from the bases of the jets. In manycases, much of the erupting-filament material forms a chromospheric-temperaturejet. In the cool-coronal channels, often the filament appears in absorption andthe hotter EUV component of the jet appears in emission. The jet bright point formsat the location from which the miniature filament erupts, analogous to theformation of a standard solar flare arcade via flare (``internal'') reconnection in the wake of the eruption of a typical larger-scale chromospheric filament. Thespire of the jet forms on open field lines that presumably have undergoneinterchange (''external'') reconnection with the erupting field that envelops andcarries the miniature filament. This is consistent with what we found for theonset of an on-disk coronal jet we examined in Adams et al. (2014), and theobservations of other workers. It is however not consistent with the basicversion of the ''emerging-flux model'' for X-ray jets. This work was supported byfunding from NASA/LWS, Hinode, and ISSI.

  2. A KPC-Scale X-Ray Jet in the BL Lac Source S5 2007+777

    NASA Technical Reports Server (NTRS)

    Sambruna, Rita M.; Donato, Davide; Cheung, C.C.; Tavecchio, F.; Maraschi, L.

    2008-01-01

    X-ray jets in AGN are commonly observed in FRII and FRI radiogalaxies, but rarely in BL Lacs, most probably due to their orientation close to the line of sight and the ensuing foreshortening effects. Only three BL Lacs are known so far to contain a kpc-scale X-ray jet. In this paper, we present the evidence for the existence of a fourth extended X-ray jet in the classical radio-selected source S5 2007+777, which for its hybrid FRI/II radio morphology has been classified as a HYMOR (HYbrid MOrphology Radio source). Our Chandra ACISS observations of this source revealed an X-ray counterpart to the 19"-long radio jet. Interestingly, the X-ray properties of the kpc-scale jet in S5 2007+777 are very similar to those observed in FRII jets. First, the X-ray morphology closely mirrors the radio one, with the X-rays being concentrated in the discrete radio knots. Second, the X-ray continuum of the jet/brightest knot is described by a very hard power law, with photon index gamma(sub x) approximately 1. Third, the optical upper limit from archival HST data implies a concave radio-to-X-ray SED. If the X-ray emission is attributed to IC/CMB with equipartition, strong beaming (delta= 13) is required, implying a very large scale (Mpc) jet. The beaming requirement can be somewhat relaxed assuming a magnetic field lower than equipartition. Alternatively, synchrotron emission from a second population of very high-energy electrons is viable. Comparison to other HYMOR jets detected with Chandra is discussed, as well as general implications for the origin of the FRI/II division.

  3. A disc corona-jet model for the radio/X-ray correlation in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Qiao, Erlin; Liu, B. F.

    2015-04-01

    The observed tight radio/X-ray correlation in the low spectral state of some black hole X-ray binaries implies the strong coupling of the accretion and jet. The correlation of L_R ∝ L_X^{˜ 0.5-0.7} was well explained by the coupling of a radiatively inefficient accretion flow and a jet. Recently, however, a growing number of sources show more complicated radio/X-ray correlations, e.g. L_R ∝ L_X^{˜ 1.4} for LX/LEdd ≳ 10-3, which is suggested to be explained by the coupling of a radiatively efficient accretion flow and a jet. In this work, we interpret the deviation from the initial radio/X-ray correlation for LX/LEdd ≳ 10-3 with a detailed disc corona-jet model. In this model, the disc and corona are radiatively and dynamically coupled. Assuming a fraction of the matter in the accretion flow, η ≡ dot{M}_jet/dot{M}, is ejected to form the jet, we can calculate the emergent spectrum of the disc corona-jet system. We calculate LR and LX at different dot{M}, adjusting η to fit the observed radio/X-ray correlation of the black hole X-ray transient H1743-322 for LX/LEdd > 10-3. It is found that always the X-ray emission is dominated by the disc corona and the radio emission is dominated by the jet. We noted that the value of η for the deviated radio/X-ray correlation for LX/LEdd > 10-3 is systematically less than that of the case for LX/LEdd < 10-3, which is consistent with the general idea that the jet is often relatively suppressed at the high-luminosity phase in black hole X-ray binaries.

  4. Spectacular X-ray Jet Points Toward Cosmic Energy Booster

    NASA Astrophysics Data System (ADS)

    2000-06-01

    NASA's Chandra X-ray Observatory has revealed a spectacular luminous spike of X rays that emanates from the vicinity of a giant black hole in the center of the radio galaxy Pictor A. The spike, or jet, is due to a beam of particles that streaks across hundreds of thousands of light years of intergalactic space toward a brilliant X-ray hot spot that marks its end point. Pictor A Image Press Image and Caption The hot spot is at least 800 thousand light years (8 times the diameter of our Milky Way galaxy) away from where the jet originates. It is thought to represent the advancing head of the jet, which brightens conspicuously where it plows into the tenuous gas of intergalactic space. The jet, powered by the giant black hole, originates from a region of space no bigger than the solar system. "Both the brightness and the spectrum of the X rays are very different from what theory predicts," Professor Andrew Wilson reported today at the 196th national meeting of the American Astronomical Society in Rochester, New York. Wilson, of the University of Maryland, College Park, along with Dr. Patrick Shopbell and Dr. Andrew Young, also of the University of Maryland, are submitting an article on this research to the Astrophysical Journal. "The Chandra observations are telling us that something out there is producing many more high-energy particles than we expected," said Wilson. One possible explanation for the X rays is that shock waves along the side and head of the X-ray jet are accelerating electrons and possibly protons to speeds close to that of light. In the process the electrons are boosted to energies as high as 100 million times their own rest mass energy. These electrons lose their energy rapidly as they produce X rays, so this could be the first direct evidence of this process so far outside a galaxy. The hot spot has been seen with optical and radio telescopes. Radio telescopes have also observed a faint jet. Jets are thought to be produced by the extreme

  5. High-Speed X-ray Investigation of Granular Jets

    NASA Astrophysics Data System (ADS)

    Royer, John; Corwin, Eric; Flior, Andrew; Conyers, Bryan; Cordero, Maria-Luisa; Rivers, Mark; Eng, Peter; Jaeger, Heinrich

    2006-03-01

    When a heavy sphere is dropped onto a bed of loose, fine sand, a large, focused jet of sand shoots upward. Experiments at reduced air pressure reveal that the jet in fact consists of two components: a wispy, thin jet that varies little with pressure followed by a thick air-pressure-driven jet. To observe the initial stages of jet formation inside the granular bed, we employed x-ray radiography using the high-intensity beams available at the Advanced Photon Source. This technique allowed us to image the motion of the sphere and the evolution of the void left behind it at frame rates up to 6600 frames per second. The x-ray movies reveal that gravity-driven collapse produces the initial, thin jet, while the compression of an air pocket trapped below the surface drives up the thick jet. We also find that the interstitial air alters the compressibility of the sand bed. In vacuum a visible compaction front precedes the ball, while at atmospheric pressure the sand flows out of the way of the ball, behaving more like an incompressible fluid. Thoroddsen, S. T. and Shen, A. Q. Phys. Fluids 13, 4-6 (2001). Lohse, D. et al. Phys. Rev. Lett. 93 (2004). Royer, J. et al. Nature Physics, December 2005.

  6. The Spectacular Radio-Near-IR-X-Ray Jet of 3C 111

    NASA Astrophysics Data System (ADS)

    Clautice, Devon; Perlman, Eric S.; Georganopoulos, Markos; Lister, Matthew L.; Tombesi, Francesco; Cara, Mihai; Marshall, Herman L.; Hogan, Brandon Scott; Kazanas, Demos

    2016-01-01

    Relativistic jets from active galactic nuclei (AGN) are powerful phenomena that transport prodigious amounts of energy and mass from the core of a galaxy out to kiloparsec or even megaparsec distances. While most spatially-resolved jets are seen in the radio, an increasing number have been discovered to emit in the optical/near-IR and/or X-ray bands. Here we discuss a spectacular example of this class, the 3C 111 jet, housed in one of the nearest, double-lobed FR II radio galaxies known. The jet itself extends over 100 kpc on each side, making it one of the longest to be seen in the radio, near-IR/optical and X-ray bands; its length and straight nature makes it ideal for studying jet physics over many kiloparsecs. We discuss new, deep Chandra and HST observations that reveal both near-IR and X-ray emission from several components of the 3C 111 jet, as well as both the approaching and receding hotspots. We also discuss new VLA observations of the jet. The near-IR and X-ray emission in the jet is restricted to several knots, and there are important differences between the morphologies seen in the radio, near-IR bands, and X-ray bands. We analyze the broad-band spectral energy distributions of the jet components. We compare competing models of emission as they relate to frequency-dependent relativistic beaming. Synchrotron emission seems to fit adequately the observed emissions of all knots and hotspots.

  7. Toward Active X-ray Telescopes II

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Aldroft, Thomas L.; Atkins, Carolyn; Button, Timothy W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peter; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Johnson-Wilke, Raegan L.; Kolodziejczak, Jeffery J.; Lillie, Charles F.; Michette, Alan G.; Ramsey, Brian D.; Reid, Paul B.; Sanmartin, Daniel Rodriguez; Saha, Timo T.; Schwartz, Daniel A.; Trolier-McKinstry, Susan E.; Ulmer, Melville P.; Wilke, Rudeger H. T.; Willingale, Richard; Zhang, William W.

    2012-01-01

    In the half century since the initial discovery of an astronomical (non-solar) x-ray source, the sensitivity for detection of cosmic x-ray sources has improved by ten orders of magnitude. Largely responsible for this dramatic progress has been the refinement of the (grazing-incidence) focusing x-ray telescope. The future of x-ray astronomy relies upon the development of x-ray telescopes with larger aperture areas (greater than 1 m2) and finer angular resolution (less than 1.). Combined with the special requirements of grazing-incidence optics, the mass and envelope constraints of space-borne telescopes render such advances technologically challenging.requiring precision fabrication, alignment, and assembly of large areas (greater than 100 m2) of lightweight (approximately 1 kg m2 areal density) mirrors. Achieving precise and stable alignment and figure control may entail active (in-space adjustable) x-ray optics. This paper discusses relevant programmatic and technological issues and summarizes progress toward active x-ray telescopes.

  8. Linking jet emission and X-ray properties in the peculiar neutron star X-ray binary Circinus X-1

    NASA Astrophysics Data System (ADS)

    Soleri, Paolo; Tudose, Valeriu; Fender, Rob; van der Klis, Michiel; Jonker, Peter G.

    2009-10-01

    We present the results of simultaneous X-ray and radio observations of the peculiar Z-type neutron star X-ray binary Cir X-1, observed with the Rossi X-ray Timing Explorer satellite and the Australia Telescope Compact Array in 2000 October and 2002 December. We identify typical Z-source behaviour in the power density spectra as well as characteristic Z patterns drawn in an X-ray hardness-intensity diagram. Power spectra typical of bright atoll sources have also been identified at orbital phases after the periastron passage, while orbital phases before the periastron passage are characterized by power spectra that are typical neither of Z nor of atoll sources. We investigate the coupling between the X-ray and the radio properties, focusing on three orbital phases when an enhancement of the radio flux density has been detected, to test the link between the inflow (X-ray) and the outflow (radio jet) to/from the compact object. In two out of three cases, we associate the presence of the radio jet to a spectral transition in the X-rays, although the transition does not precede the radio flare, as detected in other Z sources. An analogous behaviour has recently been found in the black hole candidate GX 339-4. In the third case, the radio light curve shows a similar shape to the X-ray light curve. We discuss our results in the context of jet models, considering also black hole candidates.

  9. Determining the X-ray Emission Mechanism for the Large-Scale Quasar Jet of 3C 111

    NASA Astrophysics Data System (ADS)

    Clautice, Devon; Perlman, Eric S.; Georganopoulos, Markos; Lister, Matthew L.; Tombesi, Francesco; Cara, Mihai; Marshall, Herman L.; Hogan, Brandon Scott; Kazanas, Demos

    2016-04-01

    Relativistic jets from active galactic nuclei (AGN) are powerful phenomena that transport prodigious amounts of energy and mass from the core of a galaxy out to kiloparsec or even megaparsec distances. While most spatially-resolved jets are seen in the radio, an increasing number have been discovered to emit in the optical/near-IR and/or X-ray bands. Here we discuss a spectacular example of this class, the 3C 111 jet, housed in one of the nearest, double-lobed FR II radio galaxies known. The jet itself extends over 100 kpc on each side, making it one of the longest to be seen in the radio, near-IR/optical and X-ray bands. Its length and straight nature makes it ideal for studying jet physics over many kiloparsecs. We discuss new, deep Chandra and HST observations that reveal both near-IR and X-ray emission from several components of the 3C 111 jet, as well as both the approaching and receding hotspots. The near-IR and X-ray emission in the jet is restricted to several knots, and there are important differences between the morphologies seen in the radio, near-IR, and X-ray bands. In several jet regions we detect X-ray maxima significantly upstream of the radio maxima. We analyze the broad-band spectral energy distributions of the jet components and the X-ray spectra of the brightest regions. We compare competing models of emission as they relate to frequency-dependent relativistic beaming. The morphological differences coupled with the X-ray spectral slopes lead us to favor the two-component synchrotron model and disfavor the IC/CMB model.

  10. X-ray supermirrors for BESSY II

    SciTech Connect

    Erko, A.; Schaefers, F.; Vidal, B.; Yakshin, A.; Pietsch, U.; Mahler, W.

    1995-10-01

    X-ray multilayer supermirrors for the energy range up to 20 keV have been theoretically studied and experimentally measured with synchrotron radiation. A multilayer mirror with 50 W/Si bilayers with different thicknesses on the Si substrate has a smooth reflectivity of up to 32% in the whole energy range from 5 to 22 keV at a grazing incidence angle of 0.32{degree} which is considerably larger than using total external reflection. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  11. NSLS-II X-Ray Diagnostics Development

    SciTech Connect

    ILINSKI, P.

    2011-03-28

    NSLS-II x-ray diagnostics will provide continuous online data of electron beam dimensions, which will be used to derive electron beam emittance and energy spread. It will also provide information of electron beam tilt for coupling evaluation. X-ray diagnostics will be based on imaging of bending magnet and three-pole wiggler synchrotron radiation sources. Diagnostics from three-pole wiggler source will be used to derive particles energy spread. Beta and dispersion functions will have to be evaluated for emittance and particles energy spread calculations. Due to small vertical source sizes imaging need to be performed in x-ray energy range. X-ray optics with high numerical aperture, such as compound refractive lens, will be used to achieve required spatial resolution. Optical setups with different magnifications in horizontal and vertical directions fill be employed to deal with large aspect ratio of the source. X-ray diagnostics setup will include x-ray imaging optics, monochromatization, x-ray imaging and recording components.

  12. The 300 Kpc Long X-Ray Jet in PKS 1127-145, Z=1.18 Quasar: Constraining X-Ray Emission Models

    SciTech Connect

    Siemiginowska, Aneta; Stawarz, Lukasz; Cheung, C.C.; Harris, D.E.; Sikora, Marek; Aldcroft, Thomas L.; Bechtold, Jill; /Arizona U., Astron. Dept. - Steward Observ.

    2006-11-20

    We present a {approx} 100 ksec Chandra X-ray observation and new VLA radio data of the large scale, 300 kpc long X-ray jet in PKS 1127-145, a radio loud quasar at redshift z=1.18. With this deep X-ray observation we now clearly discern the complex X-ray jet morphology and see substructure within the knots. The X-ray and radio jet intensity profiles are seen to be strikingly different with the radio emission peaking strongly at the two outer knots while the X-ray emission is strongest in the inner jet region. The jet X-ray surface brightness gradually decreases by an order of magnitude going out from the core. The new X-ray data contain sufficient counts to do spectral analysis of the key jet features. The X-ray energy index of the inner jet is relatively flat with {alpha}{sub x} = 0.66 {+-} 0.15 and steep in the outer jet with {alpha}{sub x} = 1.0 {+-} 0.2. We discuss the constraints implied by the new data on the X-ray emission models and conclude that ''one-zone'' models fail and at least a two component model is needed to explain the jet's broad-band emission. We propose that the X-ray emission originates in the jet proper while the bulk of the radio emission comes from a surrounding jet sheath. We also consider intermittent jet activity as a possible cause of the observed jet morphology.

  13. Observations of breakup processes of liquid jets using real-time X-ray radiography

    NASA Technical Reports Server (NTRS)

    Char, J. M.; Kuo, K. K.; Hsieh, K. C.

    1988-01-01

    To unravel the liquid-jet breakup process in the nondilute region, a newly developed system of real-time X-ray radiography, an advanced digital image processor, and a high-speed video camera were used. Based upon recorded X-ray images, the inner structure of a liquid jet during breakup was observed. The jet divergence angle, jet breakup length, and fraction distributions along the axial and transverse directions of the liquid jets were determined in the near-injector region. Both wall- and free-jet tests were conducted to study the effect of wall friction on the jet breakup process.

  14. The transmission X-ray microscope at BESSY II

    NASA Astrophysics Data System (ADS)

    Guttmann, P.; Niemann, B.; Rehbein, S.; Knöchel, C.; Rudolph, D.; Schmahl, G.

    2003-03-01

    The new transmission X-ray microscope (TXM) at BESSY II is the first one using soft X-rays in the water window region at an undulator beamline. For this, the condenser monochromator has been adapted to the highly collimated X-ray beam of the undulator U41. This is done by using a rotating condenser (RK) which can match the numerical aperture of any micro objective zone plate [1]. The actual setup of the TXM is given in this report. Several beam diagnostic instruments have been incorporated into the beamline and the microscope to adjust the optical elements and to study the behaviour of the complete system. The results of the characterization done so far will be presented as well as first images of applications will be shown.

  15. Integral field spectroscopy of the ultraluminous X-ray source Holmberg II X-1

    NASA Astrophysics Data System (ADS)

    Lehmann, I.; Becker, T.; Fabrika, S.; Roth, M.; Miyaji, T.; Afanasiev, V.; Sholukhova, O.; Sánchez, S. F.; Greiner, J.; Hasinger, G.; Costantini, E.; Surkov, A.; Burenkov, A.

    2005-03-01

    We present optical integral field observations of the H II region containing the ultraluminous X-ray source Holmberg II X-1. We confirm the existence of an X-ray ionized nebula as the counterpart of the source owing to the detection of an extended He II λ4686 region (21× 47 pc) at the Chandra ACIS-S position. An extended blue object with a size of 11× 14 pc is coincident with the X-ray/He II λ4686 region, which could indicate that it is either a young stellar complex or a cluster. We have derived an X-ray to optical luminosity ratio of L_X/LB≥170, and presumable it is L_X/LB˜300{-}400 using the recent HST ACS data. We find a complex velocity dispersion at the position of the ULX. In addition, there is a radial velocity variation in the X-ray ionized region found in the He II emission of ±50 km s-1 on spatial scales of 2 3primeprime. We believe that the putative black hole not only ionizes the surrounding HII gas, but also perturbs it dynamically (via jets or the accretion disk wind). The spatial analysis of the public Chandra ACIS-S data reveals a point-like X-ray source and gives marginal indication of an extended component (ll15% of the total flux). The XMM-Newton EPIC-PN spectrum of HoII X-1 is best fitted with an absorbed power law in addition to either a thermal thick plasma or a thermal thin plasma or a multi-colour disk black body (MCD). In all cases, the thermal component shows a relatively low temperature (kT˜0.14{-}0.22 keV). Finally we discuss the optical/X-ray properties of HoII X-1 with regards to the possible nature of the source. The existence of an X-ray ionized nebula coincident with the ULX and the soft X-ray component with a cool accretion disk favours the interpretation as an intermediate-mass black hole (IMBH). However, the complex velocity behaviour at the position of the ULX indicates a dynamical influence of the black hole on the local HII gas.

  16. SOLAR POLAR X-RAY JETS AND MULTIPLE BRIGHT POINTS: EVIDENCE FOR SYMPATHETIC ACTIVITY

    SciTech Connect

    Pucci, Stefano; Romoli, Marco; Poletto, Giannina; Sterling, Alphonse C.

    2012-02-15

    We present an analysis of X-ray bright points (BPs) and X-ray jets observed by Hinode/X-Ray Telescope on 2007 November 2-4, within the solar northern polar coronal hole. After selecting small subregions that include several BPs, we followed their brightness evolution over a time interval of a few hours, when several jets were observed. We find that most of the jets occurred in close temporal association with brightness maxima in multiple BPs: more precisely, most jets are closely correlated with the brightening of at least two BPs. We suggest that the jets result from magnetic connectivity changes that also induce the BP variability. We surmise that the jets and implied magnetic connectivity we describe are small-scale versions of the active-region-scale phenomenon, whereby flares and eruptions are triggered by interacting bipoles.

  17. A microfocus x-ray source based on a nonmetal liquid-jet anode

    SciTech Connect

    Tuohimaa, T.; Ewald, J.; Schlie, M.; Hertz, H. M.; Vogt, U.

    2008-06-09

    We demonstrate stable operation of a nonmetallic anode in an electron-impact x-ray source. A high-brightness electron beam is focused on a {approx}70 m/s speed, {approx}10 {mu}m diameter methanol jet producing stable x-ray emission with peak spectral brightness at {approx}5.4x10{sup 5} photons/(sx{mu}m{sup 2}xsrx0.1%BW). The jet is fully evaporated in the interaction point. The shape of a simulated spectrum using Monte Carlo methods shows good agreement with experimental data, and the theoretical brightness values give an upper limit for the achievable x-ray emission from jets with very high velocities. Using this anode concept, all compounds and elements found in liquid form are potentially usable for x-ray generation.

  18. HARD X-RAY OBSERVATIONS OF A JET AND ACCELERATED ELECTRONS IN THE CORONA

    SciTech Connect

    Glesener, Lindsay; Lin, R. P.; Krucker, Saem

    2012-07-20

    We report the first hard X-ray observation of a solar jet on the limb with flare footpoints occulted, so that faint emission from accelerated electrons in the corona can be studied in detail. In this event on 2003 August 21, RHESSI observed a double coronal hard X-ray source in the pre-impulsive phase at both thermal and nonthermal energies. In the impulsive phase, the first of two hard X-ray bursts consists of a single thermal/nonthermal source coinciding with the lower of the two earlier sources, and the second burst shows an additional nonthermal, elongated source, spatially and temporally coincident with the coronal jet. Analysis of the jet hard X-ray source shows that collisional losses by accelerated electrons can deposit enough energy to generate the jet. The hard X-ray time profile above 20 keV matches that of the accompanying Type III and broadband gyrosynchrotron radio emission, indicating both accelerated electrons escaping outward along the jet path and electrons trapped in the flare loop. The double coronal hard X-ray source, the open field lines indicated by Type III bursts, and the presence of a small post-flare loop are consistent with significant electron acceleration in an interchange reconnection geometry.

  19. New Chandra observations of the jet in 3C273. 1. Softer X-ray than radio spectra and the X-ray emission mechanism

    SciTech Connect

    Jester, Sebastian; Harris, D.E.; Marshall, H.L.; Meisenheimer, K.; /Heidelberg, Max Planck Inst. Astron.

    2006-05-01

    The jet in 3C273 is a high-power quasar jet with radio, optical and X-ray emission whose size and brightness allow a detailed study of the emission processes acting in it. We present deep Chandra observations of this jet and analyze the spectral properties of the jet emission from radio through X-rays. We find that the X-ray spectra are significantly softer than the radio spectra in all regions of the bright part of the jet except for the first bright ''knot A'', ruling out a model in which the X-ray emission from the entire jet arises from beamed inverse-Compton scattering of cosmic microwave background photons in a single-zone jet flow. Within two-zone jet models, we find that a synchrotron origin for the jet's X-rays requires fewer additional assumptions than an inverse-Compton model, especially if velocity shear leads to efficient particle acceleration in jet flows.

  20. Miniature Filament Eruptions and their Reconnections in X-Ray Jets: Evidence for a New Paradigm

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.

    2014-01-01

    We investigate the onset of approximately10 random X-ray jets observed by Hinode/XRT. Each jet was near the limb in a polar coronal hole, and showed a ``bright point'' in an edge of the base of the jet, as is typical for previously-observed X-ray jets. We examined SDO/AIA EUV images of each of the jets over multiple AIA channels, including 304 Ang, which detects chromospheric emissions, and 171, 193, and 211 Ang, which detect cooler-coronal emissions. We find the jets to result from eruptions of miniature (size less than approximately 10 arcsec) filaments from the bases of the jets. Much of the erupting-filament material forms a chromospheric-temperature jet. In the cool-coronal channels, often the filament appears in absorption and the jet in emission. The jet bright point forms at the location from which the miniature filament is ejected, analogous to the formation of a standard solar flare in the wake of the eruption of a typical larger-scale chromospheric filament. Thus these X-ray jets and their bright points are made by miniature filament eruptions. They are evidently produced the same way as an on-disk coronal jet we observed in Adams et al. (2014); that on-disk jet had no obvious emerging magnetic field in its base. We conclude that, for many jets, the standard idea of X-ray jets forming from reconnection between emerging flux and preexisting coronal field is incorrect. ACS and RLM were supported by funding from NASA/LWS, Hinode, and ISSI.

  1. X-ray jets from B2224+65: A Middle-aged Pulsar's New Trick

    NASA Astrophysics Data System (ADS)

    Wang, Q. Daniel; Johnson, Seth

    2015-01-01

    Pulsars, though typically not aged ones, are believed to be an important source of energetic cosmic rays. Therefore, it may not be too surprising to detect an X-ray jet associated with the middle-aged radio/X-ray pulsar B2224+65, which is well known for its very high proper motion and its trailing ``Guitar Nebula''. Most unexpected, however, is that this jet is offset from its proper motion direction by 118 degree. Furthermore, an X-ray counter jet and a faint X-ray trail associated with the ``Guitar Nebula'' are now identified in the combined data set of three epoch Chandra observations with a total exposure of 200 ks. We are carrying out a detailed measurements of the X-ray spectral variation with time and across the jets and are critically testing scenarios proposed to explain this enigmatic phenomenon. The study should have strong implications for understanding the origin of cosmic rays, as well as similar linear nonthermal X-ray-emitting features that are associated with more distant pulsars, especially pulsar wind nebula candidates in the central 100 pc region of the Galaxy.

  2. Liquid jet target x-ray tube with field emission cathode

    NASA Astrophysics Data System (ADS)

    Heid, Oliver; Polikhov, Stepan; Karpinskiy, Gennadiy; Geisler, Andreas; Bondarenko, Taras; Botyachkova, Alexandra; Frolov, Sergey; Ivanov, Vladislav

    2015-08-01

    We introduce first results of our research in a promising approach for micro focal x-ray generation. The approach combines the use of liquid metal jet target as anode and carbon based nanostructures as field emission cathode. Results of metal jet break-up CFD simulation and cold cathode performance tests are described. The planned experimental program is discussed herein as well.

  3. Chandra Observations of The X-ray Jets and Central Region in R Aquarii

    NASA Astrophysics Data System (ADS)

    Kellogg, E.; Hollis, J. M.; Pedelty, J.; Lyon, R.

    2001-05-01

    The R Aqr symbiotic binary system is understood to contain an M giant and a compact companion in an evolved stellar system of mass ~2-3 Msun. We reported at HEAD 2000 on the discovery of x-ray jets 0.1 LY in extent using Chandra, whereas radio and UV jets have been discovered in past VLA and HST observations. The SW x-ray jet, 3.8 times fainter than the NE component, is a completely new phenomenon, with no known optical, UV nor radio counterpart. The skewed shape of the jets supports earlier observations of jet precession. We report further on the morphology and x-ray spectra of jet and central components. An adaptively smoothed image of low surface brightness outer portions of the jet is presented. An x-ray spectrum analysis is presented with jet temperatures of ~1.6x 106 K. The spectrum of the central region surrounding the star appears to be hot gas at ~2.1*E7 K, plus Fe I Kα emission, with a suggestion of Kα emission from other elements of similar atomic number, whose origin is yet to be explained. We gratefully acknowledge support from NASA under grant #GO0-1062A and for EK from NASA contract # NAS8-39073.

  4. A 9 keV electron-impact liquid-gallium-jet x-ray source

    SciTech Connect

    Otendal, M.; Tuohimaa, T.; Vogt, U.; Hertz, H. M.

    2008-01-15

    We demonstrate a high-brightness compact 9 keV electron-impact microfocus x-ray source based on a liquid-gallium-jet anode. A {approx}30 W, 50 kV electron gun is focused onto the {approx}20 m/s, 30 {mu}m diameter liquid-gallium-jet anode to produce an {approx}10 {mu}m full width at half maximum x-ray spot. The peak spectral brightness is >2x10{sup 10} photons/(s mm{sup 2} mrad{sup 2}x0.1% BW). Calculation and experiments show potential for increasing this brightness by approximately three orders of magnitude, making the source suitable for laboratory-scale x-ray crystallography and hard x-ray microscopy.

  5. X-Ray Telescope Onboard Astro-E. II. Ground-Based X-Ray Characterization.

    PubMed

    Shibata, R; Ishida, M; Kunieda, H; Endo, T; Honda, H; Misaki, K; Ishida, J; Imamura, K; Hidaka, Y; Maeda, M; Tawara, Y; Ogasaka, Y; Furuzawa, A; Watanabe, M; Terashima, Y; Yoshioka, T; Okajima, T; Yamashita, K; Serlemitsos, P J; Soong, Y; Chan, K W

    2001-08-01

    X-ray characterization measurements of the x-ray telescope (XRT) onboard the Astro-E satellite were carried out at the Institute of Space and Astronautical Science (Japan) x-ray beam facility by means of a raster scan with a narrow x-ray pencil beam. The on-axis half-power diameter (HPD) was evaluated to be 1.8?-2.2?, irrespective of the x-ray energy. The on-axis effective areas of the XRTs for x-ray imaging spectrometers (XISs) were approximately 440, 320, 240, and 170 cm(2) at energies of 1.49, 4.51, 8.04, and 9.44 keV, respectively. Those of the x-ray spectrometer (XRS) were larger by 5-10%. The replication method introduced for reflector production significantly improved the imaging capability of the Advanced Satellite for Cosmology and Astrophyics (ASCA) XRT, whose HPD is ~3.6?. The increase in the effective area by a factor of 1.5-2.5, depending upon the x-ray energy, compared with that of the ASCA, was brought about by mechanical scale up and longer focal lengths. The off-axis HPDs were almost the same as those obtained on the optical axis. The field of view is defined as the off-axis angle at which the effective area becomes half of the on-axis value. The diameter of the field of view was ~19? at 1.49 keV, decreasing with increasing x-ray energy, and became ~13? at 9.44 keV. The intensity of stray light and the distribution of this kind of light on the focal plane were measured at the large off-axis angles 30? and 60?. In the entire XIS field of view (25.4 mm x 25.4 mm), the intensity of the stray light caused by a pointlike x-ray source became at most 1% of the same pointlike source that was on the optical axis.

  6. Recollimation boundary layers as X-ray sources in young stellar jets

    SciTech Connect

    Günther, Hans Moritz; Li, Zhi-Yun; Schneider, P. C.

    2014-11-01

    Young stars accrete mass from circumstellar disks and, in many cases, the accretion coincides with a phase of massive outflows, which can be highly collimated. Those jets emit predominantly in the optical and IR wavelength range. However, in several cases, X-ray and UV observations reveal a weak but highly energetic component in those jets. X-rays are observed both from stationary regions close to the star and from knots in the jet several hundred AU from the star. In this article, we show semianalytically that a fast stellar wind that is recollimated by the pressure from a slower, more massive disk wind can have the right properties to power stationary X-ray emission. The size of the shocked regions is compatible with observational constraints. Our calculations support a wind-wind interaction scenario for the high-energy emission near the base of young stellar object jets. For the specific case of DG Tau, a stellar wind with a mass-loss rate of 5 × 10{sup –10} M {sub ☉} yr{sup –1} and a wind speed of 800 km s{sup –1} reproduces the observed X-ray spectrum. We conclude that a stellar wind recollimation shock is a viable scenario to power stationary X-ray emission close to the jet launching point.

  7. Evidence for Simultaneous Jets and Disk Winds in Luminous Low-mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Homan, Jeroen; Neilsen, Joseph; Allen, Jessamyn L.; Chakrabarty, Deepto; Fender, Rob; Fridriksson, Joel K.; Remillard, Ronald A.; Schulz, Norbert

    2016-10-01

    Recent work on jets and disk winds in low-mass X-ray binaries (LMXBs) suggests that they are to a large extent mutually exclusive, with jets observed in spectrally hard states and disk winds observed in spectrally soft states. In this paper we use existing literature on jets and disk winds in the luminous neutron star (NS) LMXB GX 13+1, in combination with archival Rossi X-ray Timing Explorer data, to show that this source is likely able to produce jets and disk winds simultaneously. We find that jets and disk winds occur in the same location on the source’s track in its X-ray color–color diagram. A further study of literature on other luminous LMXBs reveals that this behavior is more common, with indications for simultaneous jets and disk winds in the black hole LMXBs V404 Cyg and GRS 1915+105 and the NS LMXBs Sco X-1 and Cir X-1. For the three sources for which we have the necessary spectral information, we find that simultaneous jets/winds all occur in their spectrally hardest states. Our findings indicate that in LMXBs with luminosities above a few tens of percent of the Eddington luminosity, jets and disk winds are not mutually exclusive, and the presence of disk winds does not necessarily result in jet suppression.

  8. X-ray grating interferometry with a liquid-metal-jet source

    SciTech Connect

    Thüring, T.; Rutishauser, S.; Stampanoni, M.; Zhou, T.; Lundström, U.; Burvall, A.; Hertz, H. M.; David, C.

    2013-08-26

    A liquid-metal-jet X-ray tube is used in an X-ray phase-contrast microscope based on a Talbot type grating interferometer. With a focal spot size in the range of a few microns and a photon flux of ∼10{sup 12} photons/s×sr, the brightness of such a source is approximately one order of magnitude higher than for a conventional microfocus source. For comparison, a standard microfocus source was used with the same grating interferometer, showing significantly increased visibility for the liquid-metal-jet arrangement. Together with the increased flux, this results in improved signal-to-noise ratio.

  9. The coupling of a disk corona and a jet for the radio/X-ray correlation in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Qiao, Erlin

    2015-08-01

    We interpret the radio/X-ray correlation of LR ∝ LX1.4 for LX/LEdd >10-3 in black hole X-ray binaries with a detailed disk corona-jet model, in which the accretion flow and the jet are connected by a parameter, ‘η’, describing the fraction of the matter in the accretion flow ejected outward to form the jet. We calculate LR and LX at different mass accretion rates, adjusting η to fit the observed radio/X-ray correlation of the black hole X-ray transient H1743-322 for LX/LEdd > 10-3. It is found that the value of η for this radio/X-ray correlation for LX/LEdd > 10-3, is systematically less than that of the case for LX/LEdd < 10-3, which is consistent with the general idea that the jet is often relatively suppressed at the high luminosity phase in black hole X-ray binaries.

  10. Wind-jet interaction in high-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Zdziarski, Andrzej

    2016-07-01

    Jets in high-mass X-ray binaries can strongly interact with the stellar wind from the donor. The interaction leads, in particular, to formation of recollimation shocks. The shocks can then accelerate electrons in the jet and lead to enhanced emission, observable in the radio and gamma-ray bands. DooSoo, Zdziarski & Heinz (2016) have formulated a condition on the maximum jet power (as a function of the jet velocity and wind rate and velocity) at which such shocks form. This criterion can explain the large difference in the radio and gamma-ray loudness between Cyg X-1 and Cyg X-3. The orbital modulation of radio emission observed in Cyg X-1 and Cyg X-3 allows a measurement of the location of the height along the jet where the bulk of emission at a given frequency occurs. Strong absorption of X-rays in the wind of Cyg X-3 is required to account for properties of the correlation of the radio emission with soft and hard X-rays. That absorption can also account for the unusual spectral and timing X-ray properties of this source.

  11. X-ray jets from B2224+65: A Middle-aged Pulsar's New Trick

    NASA Astrophysics Data System (ADS)

    Wang, Q. Daniel

    2014-11-01

    B2224+65 is well known to have a very high proper motion and to be associated with the ``Guitar Nebula'' in the opposite direction of the motion. A jet-like X-ray feature, however, is offset from its proper motion direction by 118 degree. Furthermore, the X-ray luminosity and morphology of the feature changed significantly between three Chandra observations. We are carrying out a detailed measurements of the X-ray spectral variation with time and across the feature and are critically testing scenarios proposed to explain this enigmatic system. The study will also have strong implications for understanding somewhat similar linear nonthermal X-ray-emitting features that have been identified in the central 100 pc region of the Galaxy.

  12. Small-Scale Filament Eruptions Leading to Solar X-Ray Jets

    NASA Astrophysics Data System (ADS)

    Sterling, Alphonse; Moore, Ronald; Falconer, David

    2015-04-01

    We investigate the onset of ~10 random X-ray jets observed by Hinode/XRT. Each jet was near the limb in a polar coronal hole, and showed a ``bright point'' in an edge of the base of the jet, as is typical for previously-observed X-ray jets. We examined SDO/AIA EUV images of each of the jets over multiple AIA channels, including 304 Å, which detects chromospheric emissions, and 171, 193, and 211 Å, which detect cooler-coronal emissions. We find the jets to result from eruptions of miniature (size <~10 arcsec) filaments from the bases of the jets. Much of the erupting-filament material forms a chromospheric-temperature jet. In the cool-coronal channels, often the filament appears in absorption and the hotter EUV component of the jet appears in emission. The jet bright point forms at the location from which the miniature filament erupts, analogous to the formation of a standard solar flare arcade in the wake of the eruption of a typical larger-scalechromospheric filament. The spire of the jet forms on open field lines that presumably have undergone interchange reconnection with the erupting field that envelops and carries the miniature filament. Thus these X-ray jets and their bright points are made by miniature filament eruptions via ``internal'' and ``external'' reconnection of the erupting field. This is consistent with what we found for the onset of an on-disk coronal jet we examined in Adams et al. (2014). This work was supported by funding from NASA/LWS, Hinode, and ISSI.

  13. Calculation of x-ray spectra emerging from an x-ray tube. Part II. X-ray production and filtration in x-ray targets

    SciTech Connect

    Poludniowski, Gavin G.

    2007-06-15

    A new approach to the calculation of the x-ray spectrum emerging from an x-ray tube is proposed. Theoretical results for the bremsstrahlung cross section appearing in the literature are summarized. Four different treatments of electron penetration, based on the work presented in Part I, are then used to generate bremsstrahlung spectra. These spectra are compared to experimental data at 50, 80 and 100 kVp tube potentials. The most sophisticated treatment of electron penetration was required to obtain good agreement. With this treatment both the National Institute of Standards and Technology bremsstrahlung cross sections, based on accurate partial wave calculations, and the Bethe-Heitler cross section [H. A. Bethe and W. Heitler, Proc R. Soc. London, Ser. A. 146, 83-112 (1934)] corrected by a modified Elwert factor [G. Elwert, Ann. Phys. (Leipzig) 426, 178-208 (1939)], provided good agreement to measured data. An approximate treatment of the characteristic spectrum is suggested. The dependencies of the bremsstrahlung and characteristic outputs of an x-ray tube on tube potential are compared to experimentally derived data for 70-140 kVp potentials. Agreement is to within a few percent of the total output over the entire range. The spectral predictions of the semiempirical models of Birch and Marshall [R. Birch and M. Marshall, Phys. Med. Biol. 24, 505-513 (1979)] (IPEM Report 78) and of Tucker et al. [D. M. Tucker, G. T. Barnes, and D. P. Chakraborty, Med. Phys. 18, 211-218 (1991).] are also assessed. The predictions of Tucker et al. are very close to the model developed here. The predictions of IPEM Report 78 are similar, but consistently harder for the range of tube potentials examined (50-100 kV). Unlike the semiempirical models, the model proposed here requires the introduction of no empirical and unphysical parameters in the differential bremsstrahlung cross section, bar an overall normalization factor which is close to unity.

  14. Shakeup in soft-x-ray emission. II. Plasmon satellites and x-ray photoemission spectroscopy

    NASA Astrophysics Data System (ADS)

    Livins, Peteris; Schnatterly, S. E.

    1988-04-01

    We report the first observation of a plasmon satellite in the K emission spectrum of diamond. The previously identified plasmon satellites of Al and graphite are also presented, and data is compared with an oscillator model applicable to soft-x-ray emission and photoemission. The graphite satellite is shown to exhibit an anomalous location with respect to the parent emission. We report for the Al LI-LII,III core-core transitions a spin-orbit splitting of 0.42+/-0.02 eV with a Lorentzian width of 0.67+/-0.02 eV. The oscillator model applied to x-ray photoemission predicts a shift of the plasmon satellite with respect to the zero loss line as the final-electron kinetic energy is varied.

  15. Relativistic baryonic jets from an ultraluminous supersoft X-ray source.

    PubMed

    Liu, Ji-Feng; Bai, Yu; Wang, Song; Justham, Stephen; Lu, You-Jun; Gu, Wei-Min; Liu, Qing-Zhong; Di Stefano, Rosanne; Guo, Jin-Cheng; Cabrera-Lavers, Antonio; Álvarez, Pedro; Cao, Yi; Kulkarni, Shri

    2015-12-01

    The formation of relativistic jets by an accreting compact object is one of the fundamental mysteries of astrophysics. Although the theory is poorly understood, observations of relativistic jets from systems known as microquasars (compact binary stars) have led to a well established phenomenology. Relativistic jets are not expected to be produced by sources with soft or supersoft X-ray spectra, although two such systems are known to produce relatively low-velocity bipolar outflows. Here we report the optical spectra of an ultraluminous supersoft X-ray source (ULS) in the nearby galaxy M81 (M81 ULS-1; refs 9, 10). Unexpectedly, the spectra show blueshifted, broad Hα emission lines, characteristic of baryonic jets with relativistic speeds. These time-variable emission lines have projected velocities of about 17 per cent of the speed of light, and seem to be similar to those from the prototype microquasar SS 433 (refs 11, 12). Such relativistic jets are not expected to be launched from white dwarfs, and an origin from a black hole or a neutron star is hard to reconcile with the persistence of M81 ULS-1's soft X-rays. Thus the unexpected presence of relativistic jets in a ULS challenges canonical theories of jet formation, but might be explained by a long-speculated, supercritically accreting black hole with optically thick outflows. PMID:26605521

  16. Relativistic baryonic jets from an ultraluminous supersoft X-ray source.

    PubMed

    Liu, Ji-Feng; Bai, Yu; Wang, Song; Justham, Stephen; Lu, You-Jun; Gu, Wei-Min; Liu, Qing-Zhong; Di Stefano, Rosanne; Guo, Jin-Cheng; Cabrera-Lavers, Antonio; Álvarez, Pedro; Cao, Yi; Kulkarni, Shri

    2015-12-01

    The formation of relativistic jets by an accreting compact object is one of the fundamental mysteries of astrophysics. Although the theory is poorly understood, observations of relativistic jets from systems known as microquasars (compact binary stars) have led to a well established phenomenology. Relativistic jets are not expected to be produced by sources with soft or supersoft X-ray spectra, although two such systems are known to produce relatively low-velocity bipolar outflows. Here we report the optical spectra of an ultraluminous supersoft X-ray source (ULS) in the nearby galaxy M81 (M81 ULS-1; refs 9, 10). Unexpectedly, the spectra show blueshifted, broad Hα emission lines, characteristic of baryonic jets with relativistic speeds. These time-variable emission lines have projected velocities of about 17 per cent of the speed of light, and seem to be similar to those from the prototype microquasar SS 433 (refs 11, 12). Such relativistic jets are not expected to be launched from white dwarfs, and an origin from a black hole or a neutron star is hard to reconcile with the persistence of M81 ULS-1's soft X-rays. Thus the unexpected presence of relativistic jets in a ULS challenges canonical theories of jet formation, but might be explained by a long-speculated, supercritically accreting black hole with optically thick outflows.

  17. Characterization of Scalar Mixing in Dense Gaseous Jets Using X-Ray Computed Tomography

    NASA Astrophysics Data System (ADS)

    Dunnmon, Jared; Kim, Tae Wook; Kovscek, Anthony; Fahrig, Rebecca; Ihme, Matthias

    2014-11-01

    An experimental technique based on X-Ray Computed Tomography (XCT) is used to characterize scalar mixing of gaseous jets at Reynolds numbers up to 20,000. In this study, the mixing of a krypton jet with ambient air is considered. The high radiodensity of the krypton gas enables non-intrusive volumetric measurements of gas density and mixture composition based on spatial variations in x-ray attenuation. Comparisons to theoretical and computational results are presented, and the viability of this diagnostic technique is assessed. Important aspects of x-ray attenuation theory and practice are considered in data processing and their impacts on future development of this technique are discussed. Support from DoD through the NDSEG Fellowship Program and from NIH through S10 Shared Instrumentation Grant S10RR026714-01 are gratefully acknowledged.

  18. Bayesian analysis of X-ray jet features of the high redshift quasar jets observed with Chandra

    NASA Astrophysics Data System (ADS)

    McKeough, Kathryn; Siemiginowska, Aneta; Kashyap, Vinay; Stein, Nathan; Cheung, Chi C.

    2015-01-01

    X-ray emission of powerful quasar jets may be a result of the inverse Compton (IC) process in which the Cosmic Microwave Background (CMB) photons gain energy by interactions with the jet's relativistic electrons. However, there is no definite evidence that IC/CMB process is responsible for the observed X-ray emission of large scale jets. A step toward understanding the X-ray emission process is to study the Radio and X-ray morphologies of the jet. Results from Chandra X-ray and multi-frequency VLA imaging observations of a sample of 11 high- redshift (z > 2) quasars with kilo-parsec scale radio jets are reported. The sample consists of a set of four z ≥ 3.6 flat-spectrum radio quasars, and seven intermediate redshift (z = 2.1 - 2.9) quasars comprised of four sources with integrated steep radio spectra and three with flat radio spectra.We implement a Bayesian image analysis program, Low-count Image Reconstruction and Analysis (LIRA) , to analyze jet features in the X-ray images of the high redshift quasars. Out of the 36 regions where knots are visible in the radio jets, nine showed detectable X-ray emission. Significant detections are based on the upper bound p-value test based on LIRA simulations. The X-ray and radio properties of this sample combined are examined and compared to lower-redshift samples.This work is supported in part by the National Science Foundation REU and the Department of Defense ASSURE programs under NSF Grant no.1262851 and by the Smithsonian Institution, and by NASA Contract NAS8-39073 to the Chandra X-ray Center (CXC). This research has made use of data obtained from the Chandra Data Archive and Chandra Source Catalog, and software provided by the CXC in the application packages CIAO, ChIPS, and Sherpa. Work is also supported by the Chandra grant GO4-15099X.

  19. The coupling of a disk corona and a jet for the radio/X-ray correlation in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Qiao, Erlin

    2016-02-01

    We interpret the radio/X-ray correlation of L R ~ L X ~1.4 for L X/L Edd >~ 10-3 with a detailed disk corona-jet model, in which the accretion flow and the jet are connected by a parameter, η, describing the fraction of the matter in the accretion flow ejected outward to form the jet. We calculate L R and L X at different Ṁ, adjusting η to fit the observed radio/X-ray correlation of the black hole X-ray transient H1743-322 for L X/L Edd > 10-3. It is found that the value of η for this radio/X-ray correlation for L X/L Edd > 10-3, is systematically less than that of the case for L X/L Edd < 10-3, which is consistent with the general idea that the jet is often relatively suppressed at the high luminosity phase in black hole X-ray binaries.

  20. The pulsar B2224+65 and its jets: a two epoch X-ray analysis

    NASA Astrophysics Data System (ADS)

    Johnson, S. P.; Wang, Q. D.

    2010-10-01

    We present an X-ray morphological and spectroscopic study of the pulsar B2224+65 and its apparent jet-like X-ray features based on two epoch Chandra observations. The main X-ray feature, which shows a large directional offset from the ram-pressure confined pulsar wind nebula (Guitar nebula), is broader in apparent width and shows evidence for spectral hardening (at 95 per cent confidence) in the second epoch compared to the first. Furthermore, the sharp leading edge of the feature is found to have a proper motion consistent with that of the pulsar (~180 mas yr-1). The combined data set also provides evidence for the presence of a counter feature, albeit substantially fainter and shorter than the main one. Additional spectral trends along the major and minor axes of the feature are only marginally detected in the two epoch data, including softening counter to the direction of proper motion. Possible explanations for the X-ray features include diffuse energetic particles being confined by an organized ambient magnetic field as well as a simple ballistic jet interpretation; however, the former may have difficulty in explaining observed spectral trends between epochs and along the feature's major axis, whereas the latter may struggle to elucidate its linearity. Given the low counting statistics available in the two epoch observations, it remains difficult to determine a physical production scenario for these enigmatic X-ray emitting features with any certainty.

  1. Recollimation boundary layers as X-ray sources in young stellar jets

    NASA Astrophysics Data System (ADS)

    Guenther, Hans Moritz; Li, Zhi-Yun; Schneider, Peter C.

    2015-01-01

    Young stars accrete mass from circumstellar disks and in many cases, the accretion coincides with a phase of massive outflows, which can be highly collimated. Those jets emit predominantly in the optical and IR wavelength range. However, in several cases X-ray and UV observations reveal a weak but highly energetic component in those jets (e.g. DG Tau, HH 2, HH 154, RY Tau). X-rays are observed both from stationary regions close to the star and from knots in the jet several hundred AU from the star.Several models have been suggested in the literature to explain the emission. One of the most prominent ones is the idea of a pulsed jet outflow, where faster material catches up with previous, slower ejecta and a shock forms where they interact. However, in this contribution we want to present an alternative model, that is quasi-stationary and thus naturally explains the stationarity of the observed X-ray emission. We show semi-analytically that a fast stellar wind which is recollimated by the pressure from a slower, more massive disk wind can have the right properties to power stationary X-ray emission. The shocked regions are only a few AU wide and would not be visible in existing optical or IR imaging. Our calculations support a wind-wind interaction scenario for the high energy emission near the base of YSO jets. Since only a very small fraction of the total mass loss comes from the star, the optical and IR properties are dominated by the slower and more massive disk wind, which has been shown to explain many of the observed phaenomena.For the specific case of DG Tau, a stellar wind with a mass loss rate of 5*10-10Msun/yr and a wind speed of 800 km/s reproduces the observed X-ray spectrum. We conclude that a stellar wind recollimation shock is a viable (but not unique) scenario to power stationary X-ray emission close to the jet launching point.The shock model itself is available as a table model in XSPEC format and can be read by all major X-ray spectral fitting

  2. Fibrillar Chromospheric Spicule-Like Counterparts to an EUV and Soft X-Ray Blowout Coronal Jet

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Harra, Louise K.; Moore, Ronald L.

    2010-01-01

    We observe an erupting jet feature in a solar polar coronal hole, using data from Hinode/SOT, EIS, and XRT, with supplemental data from STEREO/EUVI. From EUV and soft X-ray (SXR) images we identify the erupting feature as a blowout coronal jet: in SXRs it is a jet with bright base, and in EUV it appears as an eruption of relatively cool (approximately 50,000 K) material of horizontal size scale approximately 30" originating from the base of the SXR jet. In SOT Ca II H images the most pronounced analog is a pair of thin (approximately 1") ejections, at the locations of either of the two legs of the erupting EUV jet. These Ca II features eventually rise beyond 45", leaving the SOT field of view, and have an appearance similar to standard spicules except that they are much taller. They have velocities similar to that of "type II" spicules, approximately 100 kilometers per second, and they appear to have spicule-like substructures splitting off from them with horizontal velocity approximately 50 kilometers per second, similar to the velocities of splitting spicules measured by Sterling et al. (2010). Motions of splitting features and of other substructures suggest that the macroscopic EUV jet is spinning or unwinding as it is ejected. This and earlier work suggests that a sub-population of Ca II type II spicules are the Ca II manifestation of portions of larger-scale erupting magnetic jets. A different sub-population of type II spicules could be blowout jets occurring on a much smaller horizontal size scale than the event we observe here.

  3. Structure of the X-Ray Emission from the Jet of 3C 273

    NASA Technical Reports Server (NTRS)

    Marshall, H. L.; Lee, J. C.; Ogle, P. M.; Drake, J. J.; Fruscione, A.; Grimes, J.; Harris, D.; Kraft, R.; Pease, D.; Schwartz, D.; Siemiginowska, A.; Lavoie, Anthony R. (Technical Monitor)

    2000-01-01

    We present images from four Chandra observations of the quasar 3C 273. The zeroth order images from two grating observations using the AXAF CCD Imaging Spectrometer (ACIS-S) detector are used to examine the structure and spectrum of the jet. The jet has at least four distinct features which are not resolved in previous observations. Using jet feature nomenclature based on HST observations, we find that knot Al is very bright in X-rays. We have measured the X-ray spectrum of this X-ray knot for the first time, obtaining a photon index of 1.36 +/- 0.11 and a flux density of 37 +/- 4 nJy at 1 keV. Combining this measurement with lower frequency data shows that a pure synchrotron model can fit the spectrum of knot Al from 4 GHz to 5 keV (over nine decades in energy) without a change of spectral slope. Knot A2 is also detected and is somewhat blended with knot B1 but synchrotron emission is not likely to explain the X-ray emission due to the spectral turnover observed in the optical-UV band. No other knots are clearly detected but there is an indication of weak emission from the eastern portion of knot H3. near the "head," which is radio-bright. There is diffuse flux which extends from 14 arcsec to 20 arcsec which shows curvature that is comparable to the optical flux found by Bahcall, et al.

  4. Evidence for Alfvén waves in solar x-ray jets.

    PubMed

    Cirtain, J W; Golub, L; Lundquist, L; van Ballegooijen, A; Savcheva, A; Shimojo, M; Deluca, E; Tsuneta, S; Sakao, T; Reeves, K; Weber, M; Kano, R; Narukage, N; Shibasaki, K

    2007-12-01

    Coronal magnetic fields are dynamic, and field lines may misalign, reassemble, and release energy by means of magnetic reconnection. Giant releases may generate solar flares and coronal mass ejections and, on a smaller scale, produce x-ray jets. Hinode observations of polar coronal holes reveal that x-ray jets have two distinct velocities: one near the Alfvén speed ( approximately 800 kilometers per second) and another near the sound speed (200 kilometers per second). Many more jets were seen than have been reported previously; we detected an average of 10 events per hour up to these speeds, whereas previous observations documented only a handful per day with lower average speeds of 200 kilometers per second. The x-ray jets are about 2 x 10(3) to 2 x 10(4) kilometers wide and 1 x 10(5) kilometers long and last from 100 to 2500 seconds. The large number of events, coupled with the high velocities of the apparent outflows, indicates that the jets may contribute to the high-speed solar wind. PMID:18063786

  5. Evidence for Alfvén waves in solar x-ray jets.

    PubMed

    Cirtain, J W; Golub, L; Lundquist, L; van Ballegooijen, A; Savcheva, A; Shimojo, M; Deluca, E; Tsuneta, S; Sakao, T; Reeves, K; Weber, M; Kano, R; Narukage, N; Shibasaki, K

    2007-12-01

    Coronal magnetic fields are dynamic, and field lines may misalign, reassemble, and release energy by means of magnetic reconnection. Giant releases may generate solar flares and coronal mass ejections and, on a smaller scale, produce x-ray jets. Hinode observations of polar coronal holes reveal that x-ray jets have two distinct velocities: one near the Alfvén speed ( approximately 800 kilometers per second) and another near the sound speed (200 kilometers per second). Many more jets were seen than have been reported previously; we detected an average of 10 events per hour up to these speeds, whereas previous observations documented only a handful per day with lower average speeds of 200 kilometers per second. The x-ray jets are about 2 x 10(3) to 2 x 10(4) kilometers wide and 1 x 10(5) kilometers long and last from 100 to 2500 seconds. The large number of events, coupled with the high velocities of the apparent outflows, indicates that the jets may contribute to the high-speed solar wind.

  6. EVIDENCE FOR POLAR X-RAY JETS AS SOURCES OF MICROSTREAM PEAKS IN THE SOLAR WIND

    SciTech Connect

    Neugebauer, Marcia

    2012-05-01

    It is proposed that the interplanetary manifestations of X-ray jets observed in solar polar coronal holes during periods of low solar activity are the peaks of the so-called microstreams observed in the fast polar solar wind. These microstreams exhibit velocity fluctuations of {+-}35 km s{sup -1}, higher kinetic temperatures, slightly higher proton fluxes, and slightly higher abundances of the low-first-ionization-potential element iron relative to oxygen ions than the average polar wind. Those properties can all be explained if the fast microstreams result from the magnetic reconnection of bright-point loops, which leads to X-ray jets which, in turn, result in solar polar plumes. Because most of the microstream peaks are bounded by discontinuities of solar origin, jets are favored over plumes for the majority of the microstream peaks.

  7. A 24 keV liquid-metal-jet x-ray source for biomedical applications

    SciTech Connect

    Larsson, D. H.; Takman, P. A. C.; Lundstroem, U.; Burvall, A.; Hertz, H. M.

    2011-12-15

    We present a high-brightness 24-keV electron-impact microfocus x-ray source based on continuous operation of a heated liquid-indium/gallium-jet anode. The 30-70 W electron beam is magnetically focused onto the jet, producing a circular 7-13 {mu}m full width half maximum x-ray spot. The measured spectral brightness at the 24.2 keV In K{sub {alpha}} line is 3 x 10{sup 9} photons/(s x mm{sup 2}x mrad{sup 2}x 0.1% BW) at 30 W electron-beam power. The high photon energy compared to existing liquid-metal-jet sources increases the penetration depth and allows imaging of thicker samples. The applicability of the source in the biomedical field is demonstrated by high-resolution imaging of a mammography phantom and a phase-contrast angiography phantom.

  8. X-ray/UV variability and the origin of soft X-ray excess emission from II Zw 177

    NASA Astrophysics Data System (ADS)

    Pal, Main; Dewangan, Gulab C.; Misra, Ranjeev; Pawar, Pramod K.

    2016-03-01

    We study X-ray and UV emission from the narrow-line Seyfert 1 galaxy II Zw 177 using a 137 ks long and another 13 ks short XMM-Newton observation performed in 2012 and 2001, respectively. Both observations show soft X-ray excess emission contributing 76.9 ± 4.9 per cent in 2012 and 58.8 ± 10.2 per cent in 2001 in the 0.3-2 keV band. We find that both blurred reflection from an ionized disc and Comptonized disc emission describe the observed soft excess well. Time-resolved spectroscopy on scales of ˜20 ks reveals strong correlation between the soft excess and the power-law components. The fractional variability amplitude Fvar derived from EPIC-pn light curves at different energy bands is nearly constant (Fvar ˜ 20 per cent). This is in contrast to other active galactic nuclei where the lack of short term variation in soft X-ray excess emission has been attributed to intense light bending in the framework of the `lamppost' model. Thus, the variations in power-law emission are most likely intrinsic to corona rather than just due to the changes of height of compact corona. The variable UV emission (Fvar ˜ 1 per cent) is uncorrelated to any of the X-ray components on short time-scales suggesting that the UV emission is not dominated by the reprocessed emission. The gradual observed decline in the UV emission in 2012 may be related to the secular decline due to the changes in the accretion rate. In this case, the short term X-ray variability is not due to the changes in the seed photons but intrinsic to the hot corona.

  9. Phase-contrast x-ray imaging with a liquid-metal-jet-anode microfocus source

    SciTech Connect

    Tuohimaa, T.; Otendal, M.; Hertz, H. M.

    2007-08-13

    Phase-contrast methods increase contrast, detail, and selectivity in x-ray imaging. Present compact x-ray sources do not provide the necessary spatial coherence with sufficient power to allow the laboratory-scale high-resolution phase-contrast imaging with adequate exposure times. In this letter, the authors demonstrate phase-contrast imaging with few-micron detail employing a compact {approx}6.5 {mu}m spot liquid-metal-jet-anode high-brightness microfocus source. The 40 W source is operated at more than ten times higher electron-beam power density than present microfocus sources and is shown to provide sufficient spatial coherence as well as scalability to high power, thereby enabling the application of phase-contrast x-ray imaging with short exposure times in clinics and laboratories.

  10. [C ii] emission from galactic nuclei in the presence of X-rays

    NASA Astrophysics Data System (ADS)

    Langer, W. D.; Pineda, J. L.

    2015-08-01

    Context. The luminosity of [C ii] is used as a probe of the star formation rate in galaxies, but the correlation breaks down in some active galactic nuclei (AGNs). Models of the [C ii] emission from galactic nuclei do not include the influence of X-rays on the carbon ionization balance, which may be a factor in reducing the [C ii] luminosity. Aims: We aim to determine the properties of the ionized carbon and its distribution among highly ionized states in the interstellar gas in galactic nuclei under the influence of X-ray sources. We calculate the [C ii] luminosity in galactic nuclei under the influence of bright sources of soft X-rays. Methods: We solve the balance equation of the ionization states of carbon as a function of X-ray flux, electron, atomic hydrogen, and molecular hydrogen density. These are input to models of [C ii] emission from the interstellar medium (ISM) in galactic nuclei representing conditions in the Galactic central molecular zone and a higher density AGN model. The behavior of the [C ii] luminosity is calculated as a function of the X-ray luminosity. We also solve the distribution of the ionization states of oxygen and nitrogen in highly ionized regions. Results: We find that the dense warm ionized medium (WIM) and dense photon dominated regions (PDRs) dominate the [C ii] emission when no X-rays are present. The X-rays in galactic nuclei can affect strongly the C+ abundance in the WIM, converting some fraction to C2+ and higher ionization states and thus reducing its [C ii] luminosity. For an X-ray luminosity L(X-ray) ≳ 1043 erg s-1 the [C ii] luminosity can be suppressed by a factor of a few, and for very strong sources, L(X-ray) >1044 erg s-1 such as found for many AGNs, the [C ii] luminosity is significantly depressed. Comparison of the model with several extragalactic sources shows that the [C ii] to far-infrared ratio declines for L(X-ray) ≳ 1043 erg s-1, in reasonable agreement with our model. Conclusions: We conclude that X-rays

  11. Blowout Jets: Evidence from Hinode/XRT for X-Ray Jets Made by Blowout Eruption of the Emerging Bipole

    NASA Technical Reports Server (NTRS)

    Moore, Ronald L.; Cirtain, Jonathan W.; Sterling, Alphonse C.

    2009-01-01

    Yamauchi et al (2004, ApJ, 605, 511) found that there are two structurally and dynamically distinct types of H macrospicules in polar coronal holes: single-column jet macrospicules and erupting-loop macrospicules. The structure and motion of the single-column jet macrospicules fit the standard Shibata reconnection picture for solar X-ray jets (Shibata et al 1992, PASJ, 44, L173). The form and motion of the erupting-loop macrospicules is reminiscent of the ejective eruption of the sheared-core-field flux rope in the filament-eruption birth of a bubble-type coronal mass ejection (CME). That roughly half of all polar H macrospicules were observed to be erupting-loop macrospicules suggests that there should be a corresponding large class of X-ray jets in which the emerging bipole at the base of the jet undergoes a blowout eruption as in a bubble-type CME, instead of staying closed as in the standard picture for X-ray jets. Along with a cartoon of the standard picture, we present a cartoon depicting the signatures to be expected of a blowout jet in high-resolution coronal X-ray movies such as from Hinode/XRT. From Hinode/XRT movies in polar coronal holes, we show: (1) examples of X-ray jets that fit the standard picture very well, and (2) other examples that do not fit the standard picture but do show signatures appropriate for blowout jets. These signatures are (1) a flare arcade inside the emerging bipole in addition to the flare arcade produced between the emerging bipole and the ambient high-reaching unipolar field by reconnection of these two fields as in the standard picture, and (2) in addition to the jet prong expected from the standard reconnection, a second jet prong or strand, one that could not be produced by the standard reconnection but could be produced by reconnection between the ambient unipolar field and one leg of an erupting core-field flux rope that has blown out the emerging bipole. We therefore infer that these "two pronged" jets are made by

  12. POTENTIAL GAMMA-RAY EMISSIONS FROM LOW-MASS X-RAY BINARY JETS

    SciTech Connect

    Zhang, Jian-Fu; Gu, Wei-Min; Liu, Tong; Xue, Li; Lu, Ju-Fu E-mail: guwm@xmu.edu.cn

    2015-06-20

    By proposing a pure leptonic radiation model, we study the potential gamma-ray emissions from the jets of low-mass X-ray binaries. In this model, the relativistic electrons that are accelerated in the jets are responsible for radiative outputs. Nevertheless, jet dynamics are dominated by magnetic and proton–matter kinetic energies. The model involves all kinds of related radiative processes and considers the evolution of relativistic electrons along the jet by numerically solving the kinetic equation. Numerical results show that the spectral energy distributions can extend up to TeV bands, in which synchrotron radiation and synchrotron self-Compton scattering are dominant components. As an example, we apply the model to the low-mass X-ray binary GX 339–4. The results not only can reproduce the currently available observations from GX 339–4, but also predict detectable radiation at GeV and TeV bands by the Fermi and CTA telescopes. Future observations with Fermi and CTA can be used to test our model, which could be employed to distinguish the origin of X-ray emissions.

  13. Jets in black-hole and neutron-star X-ray binaries

    NASA Astrophysics Data System (ADS)

    Kylafis, Nikolaos

    2016-07-01

    Jets have been observed from both neutron-star and black-hole X-ray binaries. There are many similarities between the two and a few differences. I will offer a physical explanation of the formation and destruction of jets from compact objects and I will discuss the similarities and differences in the two types. The basic concept in the physical explanation is the Cosmic Battery, the mechanism that creates the required magnetic field for the jet ejection. The Cosmic Battery operates efficiently in accretion flows consisting of an inner hot flow and an outer thin accretion disk, independently of the nature of the compact object. It is therefore natural to always expect a jet in the right part of a spectral hardness - luminosity diagram and to never expect a jet in the left part. As a consequence, most of the phenomenology of an outburst can be explained with only one parameter, the mass accretion rate.

  14. Extended X-Ray Jet in Nearby Galaxy Reveals Energy Source

    NASA Astrophysics Data System (ADS)

    1999-10-01

    NASA's Chandra X-ray Observatory has made an extraordinary image of Centaurus A, a nearby galaxy noted for its explosive activity. The image shows X-ray jets erupting from the center of the galaxy over a distance of 25,000 light years. Also detected are a group of X-ray sources clustered around the nucleus, which is believed to harbor a supermassive black hole. The X-ray jets and the cluster of sources may be a byproduct of a titanic collision between galaxies several hundred million years ago. "This image is great," said Dr. Ethan Schreier of the Space Telescope Science Institute, "For twenty years we have been trying to understand what produced the X rays seen in the Centaurus A jet. Now we at last know that the X-ray emission is produced by extremely high-energy electrons spiraling around a magnetic field." Schreier explained that the length and shape of the X-ray jet pinned down the source of the radiation. The entire length of the X-ray jet is comparable to the diameter of the Milky Way Galaxy. Other features of the image excite scientists. "Besides the jets, one of the first things I noticed about the image was the new population of sources in the center of the galaxy," said Dr. Christine Jones from the Harvard-Smithsonian Center for Astrophysics . "They are grouped in a sphere around the nucleus, which must be telling us something very fundamental about how the galaxy, and the supermassive black hole in the center, were formed." Astronomers have accumulated evidence with optical and infrared telescopes that Centaurus A collided with a small spiral galaxy several hundred million years ago. This collision is believed to have triggered a burst of star formation and supplied gas to fuel the activity of the central black hole. more - According to Dr. Giuseppina Fabbiano, of Harvard-Smithsonian, "The Chandra image is like having a whole new laboratory to work in. Now we can see the main jet, the counter jet, and the extension of the jets beyond the galaxy. It is

  15. A KPC-scale X-ray jet in the BL LAC Source S5 2007+777

    NASA Technical Reports Server (NTRS)

    Sambruna, Rita; Maraschi, Laura; Tavecchio, Fabrizio

    2008-01-01

    The BL Lac S3 2007++777, a classical radio-selected BL Lac from the sample of Stirkel et al. exhibiting an extended (19") radio jet. was observed with Chandra revealing an X-ray jet with simi1ar morphology. The hard X-ray spectrum and broad band SED is consistent with an IC/CMB origin for the X-ray emission, implying a highly relativistic flow at small angle to the line of sight with an unusually large deprojected length, 300 kpc. A structured jet consisting of a fast spine and slow wall is consistent with the observations.

  16. Formation of granular jets observed by high-speed x-ray radiography

    SciTech Connect

    Royer, J.R.; Corwin, E.I.; Flior, A.; Cordero, M.L.; Rivers, M.; Eng, P.; Jaeger, H.M.

    2010-07-20

    When a heavy sphere is dropped onto a bed of loose, fine sand, a remarkable phenomenon occurs: a large, focused jet of sand shoots upwards. Although similar looking jets are observed on impact in fluid systems, they are held together by surface tension. Surprisingly, the granular jet exists in the absence of both surface tension and cohesion, thus fluid jet models are of limited use. Previous work proposed that the jet is created solely by the gravity-driven collapse of a void left by the sphere's descent through the pack. Here we present experimental evidence that granular jets are instead driven by a more complex process involving the interaction between the sand and interstitial air. Using high-speed X-ray radiography, and high-speed digital video, we observe the formation of the jet both inside and above the bed. We find that what previously was thought of as a single jet in fact consists of two components: a wispy, thin jet that varies little with pressure followed by a thick air-pressure-driven jet. This is further evidence that qualitatively new phenomena in granular systems can emerge as a function of air pressure. Our results highlight the importance of the dynamic coupling between gas and granule motion.

  17. X-ray crystal spectrometer upgrade for ITER-like wall experiments at JET

    SciTech Connect

    Shumack, A. E.; Rzadkiewicz, J.; Chernyshova, M.; Czarski, T.; Karpinski, L.; Jakubowska, K.; Scholz, M.; Byszuk, A.; Cieszewski, R.; Kasprowicz, G.; Pozniak, K.; Wojenski, A.; Zabolotny, W.; Dominik, W.; Conway, N. J.; Dalley, S.; Tyrrell, S.; Zastrow, K.-D.; Figueiredo, J. [EFDA-CSU, Culham Science Centre, Abingdon OX14 3DB; Associação EURATOM and others

    2014-11-15

    The high resolution X-Ray crystal spectrometer at the JET tokamak has been upgraded with the main goal of measuring the tungsten impurity concentration. This is important for understanding impurity accumulation in the plasma after installation of the JET ITER-like wall (main chamber: Be, divertor: W). This contribution provides details of the upgraded spectrometer with a focus on the aspects important for spectral analysis and plasma parameter calculation. In particular, we describe the determination of the spectrometer sensitivity: important for impurity concentration determination.

  18. The Disk-Jet Connection in Radio-Loud AGN: The X-Ray Perspective

    NASA Technical Reports Server (NTRS)

    Sambruna, Rita

    2008-01-01

    Unification schemes assume that radio-loud active galactic nuclei (AGN) contain an accretion disk and a relativistic jet perpendicular to the disk, and an obscuring molecular torus. The jet dominance decreases with larger viewing angles from blazars to Broad-Line and Narrow-Line Radio Galaxies. A fundamental question is how accretion and ejecta are related. The X-rays provide a convenient window to study these issues, as they originate in the innermost nuclear regions and penetrate large obscuring columns. I review the data, using observations by Chandra but also from other currently operating high-energy experiments. Synergy with the upcoming GLAST mission will also be highlighted.

  19. X-ray crystal spectrometer upgrade for ITER-like wall experiments at JET.

    PubMed

    Shumack, A E; Rzadkiewicz, J; Chernyshova, M; Jakubowska, K; Scholz, M; Byszuk, A; Cieszewski, R; Czarski, T; Dominik, W; Karpinski, L; Kasprowicz, G; Pozniak, K; Wojenski, A; Zabolotny, W; Conway, N J; Dalley, S; Figueiredo, J; Nakano, T; Tyrrell, S; Zastrow, K-D; Zoita, V

    2014-11-01

    The high resolution X-Ray crystal spectrometer at the JET tokamak has been upgraded with the main goal of measuring the tungsten impurity concentration. This is important for understanding impurity accumulation in the plasma after installation of the JET ITER-like wall (main chamber: Be, divertor: W). This contribution provides details of the upgraded spectrometer with a focus on the aspects important for spectral analysis and plasma parameter calculation. In particular, we describe the determination of the spectrometer sensitivity: important for impurity concentration determination.

  20. A liquid jet setup for x-ray scattering experiments on complex liquids at free-electron laser sources.

    PubMed

    Steinke, I; Walther, M; Lehmkühler, F; Wochner, P; Valerio, J; Mager, R; Schroer, M A; Lee, S; Roseker, W; Jain, A; Sikorski, M; Song, S; Hartmann, R; Huth, M; Strüder, L; Sprung, M; Robert, A; Fuoss, P H; Stephenson, G B; Grübel, G

    2016-06-01

    In this paper we describe a setup for x-ray scattering experiments on complex fluids using a liquid jet. The setup supports Small and Wide Angle X-ray Scattering (SAXS/WAXS) geometries. The jet is formed by a gas-dynamic virtual nozzle (GDVN) allowing for diameters ranging between 1 μm and 20 μm at a jet length of several hundred μm. To control jet properties such as jet length, diameter, or flow rate, the instrument is equipped with several diagnostic tools. Three microscopes are installed to quantify jet dimensions and stability in situ. The setup has been used at several beamlines performing both SAXS and WAXS experiments. As a typical example we show an experiment on a colloidal dispersion in a liquid jet at the X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source free-electron laser. PMID:27370468

  1. A liquid jet setup for x-ray scattering experiments on complex liquids at free-electron laser sources

    NASA Astrophysics Data System (ADS)

    Steinke, I.; Walther, M.; Lehmkühler, F.; Wochner, P.; Valerio, J.; Mager, R.; Schroer, M. A.; Lee, S.; Roseker, W.; Jain, A.; Sikorski, M.; Song, S.; Hartmann, R.; Huth, M.; Strüder, L.; Sprung, M.; Robert, A.; Fuoss, P. H.; Stephenson, G. B.; Grübel, G.

    2016-06-01

    In this paper we describe a setup for x-ray scattering experiments on complex fluids using a liquid jet. The setup supports Small and Wide Angle X-ray Scattering (SAXS/WAXS) geometries. The jet is formed by a gas-dynamic virtual nozzle (GDVN) allowing for diameters ranging between 1 μm and 20 μm at a jet length of several hundred μm. To control jet properties such as jet length, diameter, or flow rate, the instrument is equipped with several diagnostic tools. Three microscopes are installed to quantify jet dimensions and stability in situ. The setup has been used at several beamlines performing both SAXS and WAXS experiments. As a typical example we show an experiment on a colloidal dispersion in a liquid jet at the X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source free-electron laser.

  2. Evidence for an X-Ray Jet in DG Tauri A?

    NASA Astrophysics Data System (ADS)

    Güdel, M.; Skinner, S. L.; Briggs, K. R.; Audard, M.; Arzner, K.; Telleschi, A.

    2005-06-01

    We present evidence for an X-ray jet in the T Tauri star DG Tau A based on Chandra ACIS data. DG Tau A, a jet-driving classical T Tauri star with a flat infrared spectrum, reveals an unusual X-ray spectrum that requires two thermal components with different intervening absorption column densities. The softer component shows a low temperature of T~2.9 MK, and its absorption is compatible with the stellar optical extinction (hydrogen column density NH~5×1021 cm-2). In contrast, the harder component reveals a temperature (22 MK) characteristic of active T Tauri stars, but its emission is more strongly absorbed (NH~2.8×1022 cm-2). Furthermore, the high-resolution ACIS-S image reveals a weak excess of soft (0.5-2 keV) counts at distances of 2"-4" from the star precisely along the optical jet, with a suggestive concentration at 4", where a bow shock-like structure has previously been identified in optical line observations. The energy distribution of these photons is similar to those of the stellar soft component. We interpret the soft spectral component as originating from shocks at the base of the jet, with shock-heating continuing out to a distance of at least 500 AU along the jet, whereas the hard component is most likely coronal or magnetospheric as in other young stellar systems.

  3. The Be X-ray Binary Outburst Zoo II

    NASA Astrophysics Data System (ADS)

    Kuehnel, M.; Kretschmar, P.; Nespoli, E.; Okazaki, A. T.; Schoenherr, G.; Wilson-Hodge, C. A.; Falkner, S.; Brand, T.; Anders, F.; Schwarm, F.-W.; Kreykenbohm, I.; Mueller, S.; Pottschmidt, K.; Fuerst, F.; Grinberg, V.; Wilms, J.

    2015-03-01

    We have continued our recently started systematic study of Be X-ray binary (BeXRB) outbursts. Specifically, we are developing a catalogue of outbursts including their basic properties based on nearly all available X-ray all-sky-monitors. These properties are derived by fitting asymmetric Gaussians to the outburst lightcurves. This model describes most of the outbursts covered by our preliminary catalogue well; only 13% of all datasets show more complex outburst shapes. Analyzing the basic properties, we reveal a strong correlation between the outburst length and the reached peak flux. As an example, we discuss possible models describing the observed correlation in EXO 2030+375.

  4. INFLATING A CHAIN OF X-RAY-DEFICIENT BUBBLES BY A SINGLE JET ACTIVITY EPISODE

    SciTech Connect

    Refaelovich, Michael; Soker, Noam E-mail: soker@physics.technion.ac.il

    2012-08-10

    We show that a continuous jet with time-independent launching properties can inflate a chain of close and overlapping X-ray deficient bubbles. Using the numerical code PLUTO we run 2.5D (i.e., a spherical coordinate system with cylindrical symmetry) hydrodynamic simulations and study the interaction of the jets with the intracluster medium. A key process is vortex fragmentation due to several mechanisms, including vortex-shedding and Kelvin-Helmholtz instabilities. Our results can account for the structure of two opposite chains of close bubbles as observed in the galaxy cluster Hydra A. Our results imply that the presence of multiple pairs of bubbles does not necessarily imply several jet-launching episodes. This finding might have implications for feedback mechanisms operating by jets.

  5. X-RAY EMISSION FROM STELLAR JETS BY COLLISION AGAINST HIGH-DENSITY MOLECULAR CLOUDS: AN APPLICATION TO HH 248

    SciTech Connect

    López-Santiago, J.; Ustamujic, S.; Castro, A. I. Gómez de; Bonito, R.; Orlando, S.; Orellana, M.; Miceli, M.; Albacete-Colombo, J. F.

    2015-06-10

    We investigate the plausibility of detecting X-ray emission from a stellar jet that impacts a dense molecular cloud, a scenario that may be typical for classical T Tauri stars with jets in dense star-forming complexes. We first model the impact of a jet against a dense cloud using two-dimensional axisymmetric hydrodynamic simulations, exploring different configurations of the ambient environment. Then, we compare our results with XMM-Newton observations of the Herbig–Haro object HH 248, where extended X-ray emission aligned with the optical knots is detected at the edge of the nearby IC 434 cloud. Our simulations show that a jet can produce plasma with temperatures up to 10{sup 7} K, consistent with production of X-ray emission, after impacting a dense cloud. We find that jets denser than the ambient medium but less dense than the cloud produce detectable X-ray emission only at impact with the cloud. From an exploration of the model parameter space, we constrain the physical conditions (jet density and velocity and cloud density) that reproduce the intrinsic luminosity and emission measure of the X-ray source possibly associated with HH 248 well. Thus, we suggest that the extended X-ray source close to HH 248 corresponds to a jet impacting a dense cloud.

  6. FAST X-RAY/IR CROSS-CORRELATIONS AND RELATIVISTIC JET FORMATION IN GRS 1915+105

    SciTech Connect

    Lasso-Cabrera, N. M.; Eikenberry, S. S.

    2013-10-01

    We present cross-correlation analyses of simultaneous X-ray and near-infrared (near-IR) observations of the microquasar GRS 1915+105 during relativistic jet-producing epochs (X-ray class α and β). While previous studies have linked the large amplitude IR flares and X-ray behaviors to jet formation in these states, our new analyses are sensitive to much lower amplitude IR variability, providing more sensitive probes of the jet formation process. The X-ray to IR cross-correlation function (CCF) shows significant correlations that vary in form between the different X-ray states. During low/hard dips in both classes, we find no significant X-ray/IR correlation. During high-variability epochs, we find consistently significant correlations in both α and β classes, but with strong differences in the CCF structure. The high variability α CCF shows strong anti-correlation between X-ray/IR, with the X-ray preceding the IR by ∼13 ± 2 s. The high variability β state shows a time-variable CCF structure, which is statistically significant but without a clearly consistent lag. Our simulated IR light curves, designed to match the observed CCFs, show variably flickering IR emission during the class β high-variability epoch, while class α can be fit by IR flickering with frequencies in the range 0.1-0.3 Hz, strengthening ∼10 s after every X-ray subflare. We interpret these features in the context of the X-ray-emitting accretion disk and IR emission from relativistic jet formation in GRS 1915+105, concluding that the CCF analysis places the origin in a synchrotron-emitting relativistic compact jet at a distance from the compact object of ∼0.02 AU.

  7. X-RAY EMISSION FROM TRANSIENT JET MODEL IN BLACK HOLE BINARIES

    SciTech Connect

    Pe'er, Asaf; Markoff, Sera

    2012-07-10

    While the non-thermal radio through at least near-infrared emission in the hard state in X-ray binaries (XRBs) is known to originate in jets, the source of the non-thermal X-ray component is still uncertain. We introduce a new model for this emission, which takes into account the transient nature of outflows, and show that it can explain the observed properties of the X-ray spectrum. Rapid radiative cooling of the electrons naturally accounts for the break often seen below around 10 keV, and for the canonical spectral slope F{sub {nu}}{proportional_to}{nu}{sup -1/2} observed below the break. We derive the constraints set by the data for both synchrotron- and Compton-dominated models. We show that for the synchrotron-dominated case, the jet should be launched at radii comparable to the inner radius of the disk ({approx}few 100 r{sub s} for the 2000 outburst of XTE J1118+480), with typical magnetic field B {approx}> 10{sup 6} G. We discuss the consequences of our results for the possible connection between the inflow and outflow in the hard state of XRBs.

  8. The Relation Between Accretion Rate And Jet Power in X-Ray Luminous Elliptical Galaxies

    SciTech Connect

    Allen, Steven W.; Dunn, R.J.H.; Fabian, A.C.; Taylor, G.B.; Reynolds, C.S.; /Maryland U.

    2006-03-10

    Using Chandra X-ray observations of nine nearby, X-ray luminous elliptical galaxies with good optical velocity dispersion measurements, we show that a tight correlation exists between the Bondi accretion rates calculated from the observed gas temperature and density profiles and estimated black hole masses, and the power emerging from these systems in relativistic jets. The jet powers, which are inferred from the energies and timescales required to inflate cavities observed in the surrounding X-ray emitting gas, can be related to the accretion rates using a power law model of the form log (P{sub Bondi}/10{sup 43} erg s{sup -1}) = A + B log (P{sub jet}/10{sup 43} erg s{sup -1}), with A = 0.62 {+-} 0.15 and B = 0.77 {+-} 0.18. Our results show that a significant fraction of the energy associated with the rest mass of material entering the Bondi accretion radius (2.4{sub -0.7}{sup +1.0} per cent, for P{sub jet} = 10{sup 43} erg s{sup -1}) eventually emerges in the relativistic jets. Our results have significant implications for studies of accretion, jet formation and galaxy formation. The observed tight correlation suggests that the Bondi formulae provide a reasonable description of the accretion process in these systems, despite the likely presence of magnetic pressure and angular momentum in the accreting gas. The similarity of the P{sub Bondi} and P{sub jet} values argues that a significant fraction of the matter entering the accretion radius flows down to regions close to the black holes, where the jets are presumably formed. The tight correlation between P{sub Bondi} and P{sub jet} also suggests that the accretion flows are approximately stable over timescales of a few million years. Our results show that the black hole ''engines'' at the hearts of large elliptical galaxies and groups feed back sufficient energy to stem cooling and star formation, leading naturally to the observed exponential cut off at the bright end of the galaxy luminosity function.

  9. Constraining the Parameters of Kpc-scale, Relativistic, Inverse Compton X-ray Jets in AGN

    NASA Astrophysics Data System (ADS)

    Schwartz, Daniel A.; Birkinshaw, M.; Worrall, D. M.

    2012-01-01

    The X-ray emission from extended, kpc-scale jets is commonly explained as inverse Compton scattering of the cosmic microwave background (CMB) by the same population of electrons that emit the GHz radio spectrum. The radio and X-ray flux densities, and the assumption of equipartition of magnetic and relativisitic particle energy density, give three constraints to estimate four quantities of interest: the magnetic field, relativistic electron density, bulk Lorentz factor, and angle of the jet to our line of sight. Additional assumptions, such as setting the Lorentz factor equal to the Doppler factor, are generally used, e.g., to deduce the kinetic flux along the jet. We allow the angle to the line of sight to be a free parameter, and suggest a new constraint on the Lorentz factor and therefore also the Doppler factor. As the Lorentz factor increases, the photons we receive are increasingly those emitted back towards the AGN nucleus in the jet rest frame. However the cone of enhanced CMB density lies increasingly in the opposite direction. Eventually these photons no longer fall in the small cone satisfying the head-on approximation, which is built into the expressions for inverse-Compton emissivity, and the emitted spectrum would no longer have the standard form. Accordingly, the data can be used to deduce an upper limit to the Lorentz factor as a function of the angle to the line of sight. This research was funded in part by Chandra grant GO7-8107X

  10. Mass estimation of shaped charge jets from x-ray shadow graph with new calibration curve method

    NASA Astrophysics Data System (ADS)

    Saito, Fumikazu; Kishimura, Hiroaki; Kumakura, Akira; Sakai, Shun

    2015-06-01

    In order to assess the penetration capability of the Al and Cu metal jets against a bumper structure (such as Al plate and/or Al block), we measured the initial formation process of the metal jets generated from conical shaped charge device. The shaped charge device configurations employed in the experimental and numerical investigations have conical aluminum (and cupper) liner and steel casing with PBX explosive charge. The profile and velocity of the jets are measured with flash x-ray and x-ray film system. The mass of the jet tip are estimated from x-ray images by a calibration curve method proposed by our group. Al targets are used to evaluate a penetration performance of the jets. Additionally, we have simulated the initial formation process of the shaped charge jets with Autodyne-2D hydrodynamic code, which proposed important data to compare the experimental one.

  11. Simulations Of 3D MHD Jets: The Effects Of ICM Weather And AGN History On X-ray Cavities

    NASA Astrophysics Data System (ADS)

    Mendygral, Peter; Jones, T. W.; Dolag, K.

    2011-01-01

    The powerful jets from AGN produce low density bubbles in the ICM of the host galaxy cluster that are observed as X-ray cavities. The morphology of X-ray cavities is influenced by factors such as AGN history and ICM weather. We present 3D magnetohydrodynamical (MHD) simulations of hypersonic AGN jets in realistic cluster environments that explore the relationship between these factors and cavity properties. We will also discuss the consequences on observations of X-ray cavities with synthetic observations of these simulations. This work is supported by the NSF and by the University of Minnesota Supercomputing Institute.

  12. Hard X-ray micro-spectroscopy at Berliner Elektronenspeicherring für Synchrotronstrahlung II

    NASA Astrophysics Data System (ADS)

    Erko, A.; Zizak, I.

    2009-09-01

    The capabilities of the X-ray beamlines at Berliner Elektronenspeicherring für Synchrotronstrahlung II (BESSY II) for hard X-ray measurements with micro- and nanometer spatial resolution are reviewed. The micro-X-ray fluorescence analysis (micro-XRF), micro-extended X-ray absorption fine structure (micro-EXAFS), micro-X-ray absorption near-edge structure (micro-XANES) as well as X-ray standing wave technique (XSW), X-ray beam induced current (XBIC) in combination with micro-XRF and micro-diffraction as powerful methods for organic and inorganic sample characterization with synchrotron radiation are discussed. Mono and polycapillary optical systems were used for fine X-ray focusing down to 1 µm spot size with monochromatic and white synchrotron radiation. Polycapillary based confocal detection was applied for depth-resolved micro-XRF analysis with a volume resolution down to 3.4 · 10 - 6 mm 3. Standing wave excitation in waveguides was also applied to nano-EXAFS measurements with depth resolution on the order of 1 nm. Several examples of the methods and its applications in material research, biological investigations and metal-semiconductor interfaces analysis are given.

  13. Constraining the particle spectrum in blazar jets: importance of the hard X-ray spectrum

    NASA Astrophysics Data System (ADS)

    Sinha, Atreyee; Sahayanathan, Sunder; Chitnis, Varsha

    2016-07-01

    Measurement of the spectral curvature in blazar jets can throw light on the underlying particle spectral distribution, and hence, the acceleration and diffusion processes at play. With the advent of NuSTAR and ASTROSAT, and the upcoming ASTRO-H, this curvature can now be measured accurately across the broadband X-ray energies. We will discuss results from our recent works on two HBLs, Mkn421 (Sinha et al, A&A 2015) and 1ES1011+496 (Sinha et al, ApJ submitted), and show how simultaneous measurement at hard and soft X-ray energies can be crucial in understanding the underlying particle spectrum. Detection of lognormality in blazars is beginning to hint at strong disk-jet connections. India's recently launched multiwavelength satellite, the ASTROSAT will provide simultaneous time resolved data between 0.2-80keV, along with measurements at Optical-UV energies. We will discuss prospects from ASTROSAT for studying jet triggering mechanisms in blazars.

  14. 32.8-nm X-ray laser produced in a krypton cluster jet

    SciTech Connect

    Ivanova, E P; Vinokhodov, A Yu

    2013-12-31

    We have interpreted the well-known experimental quantum yield data for a 32.8-nm X-ray laser operating at the 3d{sup 9}4d (J = 0) – 3d{sup 9}4p (J = 1) transition of Kr{sup 8+} with the use of gaseous krypton or a krypton cluster jet. Proceeding from our model we propose a novel scheme for the 32.8-nm laser produced in a krypton cluster jet. The quantum yield is shown to saturate for a plasma length of ∼300 μm, a krypton ion density n{sub Kr} ∼ (4 – 9) × 10{sup 19} cm{sup -3}, and an electron temperature Te ∼ 5000 eV. In this case, the energy conversion coefficient amounts to ∼5 × 10{sup -3} of the pump pulse energy. We propose the experimental setup for producing a highefficiency subpicosecond X-ray laser in a krypton cluster jet. (lasers)

  15. Small-scale filament eruptions as the driver of X-ray jets in solar coronal holes.

    PubMed

    Sterling, Alphonse C; Moore, Ronald L; Falconer, David A; Adams, Mitzi

    2015-07-23

    Solar X-ray jets are thought to be made by a burst of reconnection of closed magnetic field at the base of a jet with ambient open field. In the accepted version of the 'emerging-flux' model, such a reconnection occurs at a plasma current sheet between the open field and the emerging closed field, and also forms a localized X-ray brightening that is usually observed at the edge of the jet's base. Here we report high-resolution X-ray and extreme-ultraviolet observations of 20 randomly selected X-ray jets that form in coronal holes at the Sun's poles. In each jet, contrary to the emerging-flux model, a miniature version of the filament eruptions that initiate coronal mass ejections drives the jet-producing reconnection. The X-ray bright point occurs by reconnection of the 'legs' of the minifilament-carrying erupting closed field, analogous to the formation of solar flares in larger-scale eruptions. Previous observations have found that some jets are driven by base-field eruptions, but only one such study, of only one jet, provisionally questioned the emerging-flux model. Our observations support the view that solar filament eruptions are formed by a fundamental explosive magnetic process that occurs on a vast range of scales, from the biggest mass ejections and flare eruptions down to X-ray jets, and perhaps even down to smaller jets that may power coronal heating. A similar scenario has previously been suggested, but was inferred from different observations and based on a different origin of the erupting minifilament.

  16. Small-scale filament eruptions as the driver of X-ray jets in solar coronal holes.

    PubMed

    Sterling, Alphonse C; Moore, Ronald L; Falconer, David A; Adams, Mitzi

    2015-07-23

    Solar X-ray jets are thought to be made by a burst of reconnection of closed magnetic field at the base of a jet with ambient open field. In the accepted version of the 'emerging-flux' model, such a reconnection occurs at a plasma current sheet between the open field and the emerging closed field, and also forms a localized X-ray brightening that is usually observed at the edge of the jet's base. Here we report high-resolution X-ray and extreme-ultraviolet observations of 20 randomly selected X-ray jets that form in coronal holes at the Sun's poles. In each jet, contrary to the emerging-flux model, a miniature version of the filament eruptions that initiate coronal mass ejections drives the jet-producing reconnection. The X-ray bright point occurs by reconnection of the 'legs' of the minifilament-carrying erupting closed field, analogous to the formation of solar flares in larger-scale eruptions. Previous observations have found that some jets are driven by base-field eruptions, but only one such study, of only one jet, provisionally questioned the emerging-flux model. Our observations support the view that solar filament eruptions are formed by a fundamental explosive magnetic process that occurs on a vast range of scales, from the biggest mass ejections and flare eruptions down to X-ray jets, and perhaps even down to smaller jets that may power coronal heating. A similar scenario has previously been suggested, but was inferred from different observations and based on a different origin of the erupting minifilament. PMID:26147079

  17. GIANT H II REGIONS IN M101. I. X-RAY ANALYSIS OF HOT GAS

    SciTech Connect

    Sun Wei; Chen Yang; Feng Li; Chu, You-Hua; Chen, C.-H. Rosie; Wang, Q. Daniel; Li Jiangtao

    2012-11-20

    We performed a Chandra X-ray study of three giant H II regions (GHRs), NGC 5461, NGC 5462, and NGC 5471, in the spiral galaxy M101. The X-ray spectra of the three GHRs all contain a prominent thermal component with a temperature of {approx}0.2 keV. In NGC 5461, the spatial distribution of the soft (<1.5 keV) X-ray emission is generally in agreement with the extent of H1105, the most luminous H II region therein, but extends beyond its southern boundary, which could be attributed to outflows from the star cloud between H1105 and H1098. In NGC 5462, the X-ray emission is displaced from the H II regions and a ridge of blue stars; the H{alpha} filaments extending from the ridge of star cloud to the diffuse X-rays suggest that hot gas outflows have occurred. The X-rays from NGC 5471 are concentrated at the B-knot, a 'hypernova remnant' candidate. Assuming a Sedov-Taylor evolution, the derived explosion energy, on the order of 10{sup 52} erg, is consistent with a hypernova origin. In addition, a bright source in the field of NGC 5462 has been identified as a background active galactic nucleus, instead of a black hole X-ray binary in M101.

  18. Ultra-fast X-ray particle velocimetry measurements within an abrasive water jet

    NASA Astrophysics Data System (ADS)

    Balz, R.; Mokso, R.; Narayanan, C.; Weiss, D. A.; Heiniger, K. C.

    2013-03-01

    Ultra-fast X-ray velocimetry measurements were taken to measure velocities and spatial positions of individual abrasive particles within the solid-liquid-gaseous three-phase flow of a high-pressure injection method-based abrasive water jet (AWJ). A synchrotron X-ray source provided sufficient photon flux to take double-frame images of the AWJ with an inter-frame time interval of 5 μs. Abrasive particles with a Sauter mean diameter of 265.5 μm were detected by a scintillator optically coupled to a gated image intensifier and a high-speed camera running at a frame rate of 11,250 Hz. A commercially available particle tracking velocimetry software was used to process the acquired images and evaluate the spatial positions and velocities of abrasive particles as a function of water pressure and abrasive mass flow. The acquired data show a Gaussian radial distribution of abrasive particles within the AWJ and an almost uniform mean axial velocity, irrespective of water jet velocity and abrasive flow rates. These results are useful to validate theoretical models for the momentum/energy transfer in AWJ, to provide input for abrasion/erosion models, to further understand and advance the AWJ process, and to develop new process opportunities such as AWJ milling.

  19. Aborted jets and the X-ray emission of radio-quiet AGNs

    NASA Astrophysics Data System (ADS)

    Ghisellini, G.; Haardt, F.; Matt, G.

    2004-01-01

    We propose that radio-quiet quasars and Seyfert galaxies have central black holes powering outflows and jets which propagate only for a short distance, because the velocity of the ejected material is smaller than the escape velocity. We call them ``aborted" jets. If the central engine works intermittently, blobs of material may be produced, which can reach a maximum radial distance and then fall back, colliding with the blobs produced later and still moving outwards. These collisions dissipate the bulk kinetic energy of the blobs by heating the plasma, and can be responsible (entirely or at least in part) for the generation of the high energy emission in radio-quiet objects. This is alternative to the more conventional scenario in which the X-ray spectrum of radio-quiet sources originates in a hot (and possibly patchy) corona above the accretion disk. In the latter case the ultimate source of energy of the emission of both the disk and the corona is accretion. Here we instead propose that the high energy emission is powered also by the extraction of the rotational energy of the black hole (and possibly of the disk). By means of Montecarlo simulations we calculate the time dependent spectra and light curves, and discuss their relevance to the X-ray spectra in radio-quiet AGNs and galactic black hole sources. In particular, we show that time variability and spectra are similar to those observed in Narrow Line Seyfert 1 galaxies.

  20. X-Ray Absorption Spectroscopy of Strontium(II) Coordination.

    PubMed

    Sahai; Carroll; Roberts; O'Day

    2000-02-15

    Sorption of dissolved strontium on kaolinite, amorphous silica, and goethite was studied as a function of pH, aqueous strontium concentration, the presence or absence of atmospheric CO(2) or dissolved phosphate, and aging over a 57-day period. Selected sorption samples ([Sr(aq)](i) approximately 0.5-1x10(-3) m) were examined with synchrotron X-ray absorption spectroscopy (XAS) at low (13-23 K) and room temperatures to determine the local molecular coordination around strontium. Quantitative analyses of the extended X-ray absorption fine structure (EXAFS) of kaolinite, amorphous silica, and most goethite sorption samples showed a single first shell of 9-10 (+/-1) oxygen atoms around strontium at an average Sr-O bond-distance of 2.61 (+/-0.02) Å, indicating hydrated surface complexes. The EXAFS spectra were unchanged after reaction for up to 57 days. Likewise, in kaolinite sorption samples prepared in 100% nitrogen atmosphere, the presence of dissolved phosphate (0.5x10(-3) m) in addition to strontium did not change the local coordination around strontium. In two goethite sorption samples reacted in air at pH approximately 8.5, the EXAFS spectra (collected at low and room temperature) clearly showed that the local structure around strontium is that of strontianite (SrCO(3)(s)). We also noted an increase in strontium uptake on goethite in the presence of atmospheric CO(2) in batch experiments, relative to CO(2)-free experiments. These observations suggest that sorption of carbonate may nucleate the precipitation of SrCO(3) in the pH range in which carbonate sorption on goethite is near a maximum. At higher pH, carbonate surface sorption decreases as dissolved CO(2) decreases. For goethite sorption samples above pH 8.6, hydrated surface complexes, rather than a precipitate, were observed in the EXAFS spectra. Copyright 2000 Academic Press.

  1. Sub-mm Jet Properties of the X-Ray Binary Swift J1745-26

    NASA Astrophysics Data System (ADS)

    Tetarenko, A. J.; Sivakoff, G. R.; Miller-Jones, J. C. A.; Curran, P. A.; Russell, T. D.; Coulson, I. M.; Heinz, S.; Maitra, D.; Markoff, S. B.; Migliari, S.; Petitpas, G. R.; Rupen, M. P.; Rushton, A. P.; Russell, D. M.; Sarazin, C. L.

    2015-05-01

    We present the results of our observations of the early stages of the 2012-2013 outburst of the transient black hole X-ray binary (BHXRB), Swift J1745-26, with the Very Large Array, Submillimeter Array, and James Clerk Maxwell telescope (SCUBA-2). Our data mark the first multiple-band mm and sub-mm observations of a BHXRB. During our observations the system was in the hard accretion state producing a steady, compact jet. The unique combination of radio and mm/sub-mm data allows us to directly measure the spectral indices in and between the radio and mm/sub-mm regimes, including the first mm/sub-mm spectral index measured for a BHXRB. Spectral fitting revealed that both the mm (230 GHz) and sub-mm (350 GHz) measurements are consistent with extrapolations of an inverted power law from contemporaneous radio data (1-30 GHz). This indicates that, as standard jet models predict, a power law extending up to mm/sub-mm frequencies can adequately describe the spectrum, and suggests that the mechanism driving spectral inversion could be responsible for the high mm/sub-mm fluxes (compared to radio fluxes) observed in outbursting BHXRBs. While this power law is also consistent with contemporaneous optical data, the optical data could arise from either jet emission with a jet spectral break frequency of {{ν }break}≳ 1× {{10}14} Hz or the combination of jet emission with a lower jet spectral break frequency of {{ν }break}≳ 2× {{10}11} Hz and accretion disk emission. Our analysis solidifies the importance of the mm/sub-mm regime in bridging the crucial gap between radio and IR frequencies in the jet spectrum, and justifies the need to explore this regime further.

  2. Photoionization-pumped, Ne II, x-ray laser studies project. Final report

    SciTech Connect

    Richardson, M.C.; Hagelstein, P.L.; Eckart, M.J.; Forsyth, J.M.; Gerrassimenko, M.; Soures, J.M.

    1984-01-01

    The energetics of this pumping scheme are shown. Short-pulse (50 to 100 ps) laser irradiation of an appropriate x-ray flashlamp medium generates broad-band emission in the range of 300 to 800 eV which preferentially photoionizes Ne to the /sup 2/S state of Ne II creating an inversion at approximately 27 eV. Although this approach does not depend on precise spectral overlap between the x-ray pump radiation and the medium to be pumped, it does require that the x-ray medium remain un-ionized prior to photoionization by the soft x-ray emission. Well-controlled focus conditions are required to ensure that the x-ray medium is not subjected to electron or x-ray preheat prior to irradiation by the soft x-ray source. The magnitude of the population inversion is predicted to be critically dependent upon rapid photoionization of the two states; therefore, ultra-short pulse irradiation of the laser flashlamps is required.

  3. SWIFT Discovery of Gamma-ray Bursts without Jet Break Feature in their X-ray Afterglows

    NASA Technical Reports Server (NTRS)

    Sato, G.; Yamazaki, R.; Sakamoto, T.; Takahashi, T; Nakazawa, K.; Nakamura, T.; Toma, K.; Hullinger, D.; Tashiro, M.; Parsons, A. M.; Krimm, H. A.; Barthelmy, S. D.; Gehrels, N.; Burrows, D. N.; O'Brien, P. T.; Osborne, J. P.; Chincarini, G.; Lamb, D. Q.

    2007-01-01

    We analyze Swift gamma-ray bursts (GRBs) and X-ray afterglows for three GRBs with spectroscopic redshift determinations - GRB 050401, XRF 050416a, and GRB 050525a. We find that the relation between spectral peak energy and isotropic energy of prompt emissions (the Amati relation) is consistent with that for the bursts observed in pre-Swift era. However, we find that the X-ray afterglow lightcurves, which extend up to 10 - 70 days, show no sign of the jet break that is expected in the standard framework of collimated outflows. We do so by showing that none of the X-ray afterglow lightcurves in our sample satisfies the relation between the spectral and temporal indices that is predicted for the phase after jet break. The jet break time can be predicted by inverting the tight empirical relation between the peak energy of the spectrum and the collimation-corrected energy of the prompt emission (the Ghirlanda relation). We find that there are no temporal breaks within the predicted time intervals in X-ray band. This requires either that the Ghirlanda relation has a larger scatter than previously thought, that the temporal break in X-rays is masked by some additional source of X-ray emission, or that it does not happen because of some unknown reason.

  4. Interpreting the radio/X-ray correlation of black hole X-ray binaries based on the accretion-jet model

    NASA Astrophysics Data System (ADS)

    Xie, Fu-Guo; Yuan, Feng

    2016-03-01

    Two types of correlations between the radio and X-ray luminosities (LR and LX) have been found in black hole X-ray binaries. For some sources, they follow the `original' type of correlation which is described by a single power law. Later it was found that some other sources follow a different correlation consisting of three power-law branches, with each branch having different power-law indexes. In this work, we explain these two types of correlation under the coupled accretion-jet model. We attribute the difference between these two types of sources to the different value of viscosity parameter α. One possible reason for different α is the different configuration of magnetic field in the accretion material coming from the companion stars. For the `single power-law' sources, their α is high; so their accretion is always in the mode of advection-dominated accretion flow (ADAF) for the whole range of X-ray luminosity. For those `hybrid power-law' sources, the value of α is small so their accretion mode changes from an ADAF to a luminous hot accretion flow, and eventually to two-phase accretion as the accretion rate increases. Because the dependence of radiative efficiency on the mass accretion rate is different for these three accretion modes, different power-law indexes in the LR-LX correlation are expected. Constraints on the ratio of the mass-loss rate into the jet and the mass accretion rate in the accretion flow are obtained, which can be tested in future by radiative magnetohydrodynamic numerical simulations of jet formation.

  5. Possible proton synchrotron origin of X-ray and gamma-ray emission in large-scale jet of 3C 273

    NASA Astrophysics Data System (ADS)

    Kundu, Esha; Gupta, Nayantara

    2014-10-01

    The large-scale jet of quasar 3C 273 has been observed in radio to gamma-ray frequencies. Earlier the X-ray emission from knot A of this jet has been explained with inverse Compton scattering of the cosmic microwave background radiations by the shock accelerated relativistic electrons in the jet. More recently it has been shown that this mechanism overproduces the gamma-ray flux at GeV energy and violates the observational results from Fermi LAT. We have considered the synchrotron emission from a broken power-law spectrum of accelerated protons in the jet to explain the observed X-ray to gamma-ray flux from knot A. The two scenarios discussed in our work are (i) magnetic field is high, synchrotron energy loss time of the protons is shorter than their escape time from the knot region and the age of the jet and (ii) their escape time is shorter than their synchrotron energy loss time and the age of the jet. These scenarios can explain the observed photon spectrum well for moderate values of Doppler factor. The required jet luminosity is high ˜1046 erg s-1 in the first scenario and moderate ˜1045 erg s-1 in the second, which makes the second scenario more favourable.

  6. Gamma-ray burst flares: X-ray flaring. II

    SciTech Connect

    Swenson, C. A.; Roming, P. W. A.

    2014-06-10

    We present a catalog of 498 flaring periods found in gamma-ray burst (GRB) light curves taken from the online Swift X-Ray Telescope GRB Catalogue. We analyzed 680 individual light curves using a flare detection method developed and used on our UV/optical GRB Flare Catalog. This method makes use of the Bayesian Information Criterion to analyze the residuals of fitted GRB light curves and statistically determines the optimal fit to the light curve residuals in an attempt to identify any additional features. These features, which we classify as flares, are identified by iteratively adding additional 'breaks' to the light curve. We find evidence of flaring in 326 of the analyzed light curves. For those light curves with flares, we find an average number of ∼1.5 flares per GRB. As with the UV/optical, flaring in our sample is generally confined to the first 1000 s of the afterglow, but can be detected to beyond 10{sup 5} s. Only ∼50% of the detected flares follow the 'classical' definition of Δt/t ≤ 0.5, with many of the largest flares exceeding this value.

  7. 1RXS J180408.9-342058: An ultra compact X-ray binary candidate with a transient jet

    NASA Astrophysics Data System (ADS)

    Baglio, M. C.; D'Avanzo, P.; Campana, S.; Goldoni, P.; Masetti, N.; Muñoz-Darias, T.; Patiño-Álvarez, V.; Chavushyan, V.

    2016-03-01

    Aims: We present a detailed near-infrared/optical/UV study of the transient low-mass X-ray binary 1RXS J180408.9-342058 performed during its 2015 outburst, which is aimed at determining the nature of its companion star. Methods: We obtained three optical spectra (R ~ 1000) at the 2.1 m San Pedro Mártir Observatory telescope (México). We performed optical and NIR photometric observations with both the REM telescope and the New Technology Telescope (NTT) in La Silla. We obtained optical and UV observations from the Swift archive. Finally, we performed optical polarimetry of the source using the EFOSC2 instrument mounted on the NTT. Results: The optical spectrum of the source is almost featureless since the hydrogen and He I emissions lines, typically observed in LMXBs, are not detected. Similarly, carbon and oxygen lines are not observed either. We marginally detect the He II 4686 Å emission line, suggesting the presence of helium in the accretion disc. No significant optical polarisation level was observed. Conclusions: The lack of hydrogen and He I emission lines in the spectrum implies that the companion is likely not a main-sequence star. Driven by the tentative detection of the He II 4686 Å emission line, we suggest that the system could harbour a helium white dwarf. If this is the case, 1RXS J180408.9-342058 would be an ultra-compact X-ray binary. By combining an estimate of the mass accretion rate together with evolutionary tracks for a He white dwarf, we obtain a tentative orbital period of ~40 min. We also built the NIR-optical-UV spectral energy distribution (SED) of the source at two different epochs. One SED was gathered when the source was in the soft X-ray state and this SED is consistent with the presence of a single thermal component. The second SED, obtained when the source was in the hard X-ray state, shows a thermal component along with a tail in the NIR, which likely indicates the presence of a (transient) jet. Based on observations made with

  8. Stability and debris in high-brightness liquid-metal-jet-anode microfocus x-ray sources

    SciTech Connect

    Otendal, M.; Tuohimaa, T.; Hertz, H. M.

    2007-01-15

    We investigate the x-ray spot stability and the debris emission in liquid-metal-jet anode electron-impact x-ray sources operating in the 10-100 W microfocus regime. The x-ray spot size is 15-23 {mu}m in diameter and the electron-beam power density is up to {approx}210 kW/mm{sup 2}, an order of magnitude higher than for conventional microfocus sources. In the power range of the investigation the source is stable in terms of spot size and position. The debris emission rate increases exponentially with the applied electron-beam power but may be reduced by combining larger and faster target jets with smaller e-beam foci and by mitigation schemes. It is concluded that the investigated factors will not limit the performance and function of liquid-metal-jet-anode electron-impact microfocus sources when operating in this high-brightness regime.

  9. X-ray emission from cataclysmic variables with accretion disks. I - Hard X-rays. II - EUV/soft X-ray radiation

    NASA Technical Reports Server (NTRS)

    Patterson, J.; Raymond, J. C.

    1985-01-01

    Theoretical models explaining the hard-X-ray, soft-X-ray, and EUV emission of accretion-disk cataclysmic variables in terms of the disk boundary layer (DBL) are developed on the basis of a survey of the published observational data. The data are compared with model predictions in graphs for systems with high or low (greater than or less than 10-Pg/s) accretion rates. Good agreement is obtained both at low accretion rates, where an optically thin rarefied hot (Te = 10 to the 8th K) DBL radiates most of its energy as hard X-rays, and at high accretion rates, where an optically thick 100,000-K DBL radiates most of its energy in the EUV and as soft X-rays. Detailed analysis of the old nova V603 Aql suggests that previous models predicting more detections of soft-X-ray/EUV emissions from thick-DBL objects (Ferland et al., 1982) used inappropriate dwarf masses, interstellar column densities, or classical-nova space densities.

  10. Jet-ISM Interaction in the Radio Galaxy 3C 293: Jet-driven Shocks Heat ISM to Power X-Ray and Molecular H2 Emission

    NASA Astrophysics Data System (ADS)

    Lanz, L.; Ogle, P. M.; Evans, D.; Appleton, P. N.; Guillard, P.; Emonts, B.

    2015-03-01

    We present a 70 ks Chandra observation of the radio galaxy 3C 293. This galaxy belongs to the class of molecular hydrogen emission galaxies (MOHEGs) that have very luminous emission from warm molecular hydrogen. In radio galaxies, the molecular gas appears to be heated by jet-driven shocks, but exactly how this mechanism works is still poorly understood. With Chandra, we observe X-ray emission from the jets within the host galaxy and along the 100 kpc radio jets. We model the X-ray spectra of the nucleus, the inner jets, and the X-ray features along the extended radio jets. Both the nucleus and the inner jets show evidence of 107 K shock-heated gas. The kinetic power of the jets is more than sufficient to heat the X-ray emitting gas within the host galaxy. The thermal X-ray and warm H2 luminosities of 3C 293 are similar, indicating similar masses of X-ray hot gas and warm molecular gas. This is consistent with a picture where both derive from a multiphase, shocked interstellar medium (ISM). We find that radio-loud MOHEGs that are not brightest cluster galaxies (BCGs), like 3C 293, typically have LH2/LX˜ 1 and MH2/MX˜ 1, whereas MOHEGs that are BCGs have LH2/LX˜ 0.01 and MH2/MX˜ 0.01. The more massive, virialized, hot atmosphere in BCGs overwhelms any direct X-ray emission from current jet-ISM interaction. On the other hand, LH2/LX˜ 1 in the Spiderweb BCG at z = 2, which resides in an unvirialized protocluster and hosts a powerful radio source. Over time, jet-ISM interaction may contribute to the establishment of a hot atmosphere in BCGs and other massive elliptical galaxies.

  11. Collimated Jet Or Expanding Outflow: Possible Origins of GRBs And X-Ray Flashes

    SciTech Connect

    Mizuta, Akira; Yamasaki, Tatsuya; Nagataki, Shigehiro; Mineshige, Shin; /Kyoto U., Yukawa Inst., Kyoto

    2006-08-10

    transition between the GRBs, X-ray rich GRBs (XRRs) and X-ray Flashes (XRFs) by the same model but with different {epsilon}{sub 0} values.

  12. Disc-jet coupling in the Terzan 5 neutron star X-ray binary EXO 1745-248

    NASA Astrophysics Data System (ADS)

    Tetarenko, A. J.; Bahramian, A.; Sivakoff, G. R.; Tremou, E.; Linares, M.; Tudor, V.; Miller-Jones, J. C. A.; Heinke, C. O.; Chomiuk, L.; Strader, J.; Altamirano, D.; Degenaar, N.; Maccarone, T.; Patruno, A.; Sanna, A.; Wijnands, R.

    2016-07-01

    We present the results of Very Large Array, Australia Telescope Compact Array, and Swift X-ray Telescope observations of the 2015 outburst of the transient neutron star X-ray binary (NSXB), EXO 1745-248, located in the globular cluster Terzan 5. Combining (near-) simultaneous radio and X-ray measurements, we measure a correlation between the radio and X-ray luminosities of L_R∝ L_X^β with β =1.68^{+0.10}_{-0.09}, linking the accretion flow (probed by X-ray luminosity) and the compact jet (probed by radio luminosity). While such a relationship has been studied in multiple black hole X-ray binaries (BHXBs), this work marks only the third NSXB with such a measurement. Constraints on this relationship in NSXBs are strongly needed, as comparing this correlation between different classes of XB systems is key in understanding the properties that affect the jet production process in accreting objects. Our best-fitting disc-jet coupling index for EXO 1745-248 is consistent with the measured correlation in NSXB 4U 1728-34 (β = 1.5 ± 0.2) but inconsistent with the correlation we fit using the most recent measurements from the literature of NSXB Aql X-1 (β =0.76^{+0.14}_{-0.15}). While a similar disc-jet coupling index appears to hold across multiple BHXBs in the hard accretion state, this does not appear to be the case with the three NSXBs measured so far. Additionally, the normalization of the EXO 1745-248 correlation is lower than the other two NSXBs, making it one of the most radio faint XBs ever detected in the hard state. We also report the detection of a type-I X-ray burst during this outburst, where the decay time-scale is consistent with hydrogen burning.

  13. Nine Years of Observations of Hard X-Rays from Relativistic Jet Objects with BATSE

    NASA Technical Reports Server (NTRS)

    Fishman, G. J.; Harmon, B. A.; Fishman, G. J.; Six, N. Frank (Technical Monitor)

    2002-01-01

    The observed hard X-ray temporal and spectral characteristics will be displayed for over nine years of BATSE (Burst and Transient Source Experiment) data from the Compton Observatory. These observations were obtained using the Earth occultation technique, a technique that has become increasingly more sensitive and accurate as systematic effects are understood and corrected. The principal objects that are being presented in this study include: GRO J1655-40, GRS 1915+105, Cyg X-3, Cyg X-1, XTE J1550-564, XTE J1859+226, XTE J1748-288, and V4641 Sgr. Light curves and spectral will be presented and discussed in terms of relativistic jet production in these systems.

  14. Shallow Decay of Early X-Ray Afterglows from Inhomogeneous Gamma-Ray Burst Jets

    NASA Astrophysics Data System (ADS)

    Toma, Kenji; Ioka, Kunihito; Yamazaki, Ryo; Nakamura, Takashi

    2006-04-01

    Almost all the X-ray afterglows of γ-ray bursts (GRBs) observed by the Swift satellite have a shallow decay phase in their first few thousand seconds. We show that in an inhomogeneous-jet model (multiple-subjet or patchy-shell), the superposition of the afterglows of off-axis subjets (patchy shells) can produce the shallow decay phase. The necessary condition for obtaining the shallow decay phase is that γ-ray-bright subjets (patchy shells) have γ-ray efficiencies higher than previously estimated and that they be surrounded by γ-ray-dim subjets (patchy shells) with low γ-ray efficiency. Our model predicts that events with dim prompt emission will have a conventional afterglow light curve without a shallow decay phase, like GRB 050416A.

  15. NuSTAR Hard X-Ray Survey of the Galactic Center Region. II. X-Ray Point Sources

    NASA Astrophysics Data System (ADS)

    Hong, JaeSub; Mori, Kaya; Hailey, Charles J.; Nynka, Melania; Zhang, Shuo; Gotthelf, Eric; Fornasini, Francesca M.; Krivonos, Roman; Bauer, Franz; Perez, Kerstin; Tomsick, John A.; Bodaghee, Arash; Chiu, Jeng-Lun; Clavel, Maïca; Stern, Daniel; Grindlay, Jonathan E.; Alexander, David M.; Aramaki, Tsuguo; Baganoff, Frederick K.; Barret, Didier; Barrière, Nicolas; Boggs, Steven E.; Canipe, Alicia M.; Christensen, Finn E.; Craig, William W.; Desai, Meera A.; Forster, Karl; Giommi, Paolo; Grefenstette, Brian W.; Harrison, Fiona A.; Hong, Dooran; Hornstrup, Allan; Kitaguchi, Takao; Koglin, Jason E.; Madsen, Kristen K.; Mao, Peter H.; Miyasaka, Hiromasa; Perri, Matteo; Pivovaroff, Michael J.; Puccetti, Simonetta; Rana, Vikram; Westergaard, Niels J.; Zhang, William W.; Zoglauer, Andreas

    2016-07-01

    We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3–79 keV) X-ray point sources in a 0.6 deg{}2 region around Sgr A* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ˜4× and ˜8 × 10{}32 erg s{}-1 at the GC (8 kpc) in the 3–10 and 10–40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources suggests that magnetic cataclysmic variables constitute a large fraction (>40%–60%). Both spectral analysis and logN–logS distributions of the NuSTAR sources indicate that the X-ray spectra of the NuSTAR sources should have kT > 20 keV on average for a single temperature thermal plasma model or an average photon index of Γ = 1.5–2 for a power-law model. These findings suggest that the GC X-ray source population may contain a larger fraction of XBs with high plasma temperatures than the field population.

  16. Serendipitous Discovery of an Extended X-Ray Jet without a Radio Counterpart in a High-redshift Quasar

    NASA Astrophysics Data System (ADS)

    Simionescu, A.; Stawarz, Ł.; Ichinohe, Y.; Cheung, C. C.; Jamrozy, M.; Siemiginowska, A.; Hagino, K.; Gandhi, P.; Werner, N.

    2016-01-01

    A recent Chandra observation of the nearby galaxy cluster Abell 585 has led to the discovery of an extended X-ray jet associated with the high-redshift background quasar B3 0727+409, a luminous radio source at redshift z = 2.5. This is one of only few examples of high-redshift X-ray jets known to date. It has a clear extension of about 12″, corresponding to a projected length of ∼100 kpc, with a possible hot spot located 35″ from the quasar. The archival high resolution Very Large Array maps surprisingly reveal no extended jet emission, except for one knot about 1.″4 from the quasar. The high X-ray to radio luminosity ratio for this source appears consistent with the \\propto {(1+z)}4 amplification expected from the inverse Compton radiative model. This serendipitous discovery may signal the existence of an entire population of similar systems with bright X-ray and faint radio jets at high redshift, a selection bias that must be accounted for when drawing any conclusions about the redshift evolution of jet properties and indeed about the cosmological evolution of supermassive black holes and active galactic nuclei in general.

  17. Chandra ACIS Survey of X-Ray Point Sources in Nearby Galaxies. II. X-Ray Luminosity Functions and Ultraluminous X-Ray Sources

    NASA Astrophysics Data System (ADS)

    Wang, Song; Qiu, Yanli; Liu, Jifeng; Bregman, Joel N.

    2016-09-01

    Based on the recently completed Chandra/ACIS survey of X-ray point sources in nearby galaxies, we study the X-ray luminosity functions (XLFs) for X-ray point sources in different types of galaxies and the statistical properties of ultraluminous X-ray sources (ULXs). Uniform procedures are developed to compute the detection threshold, to estimate the foreground/background contamination, and to calculate the XLFs for individual galaxies and groups of galaxies, resulting in an XLF library of 343 galaxies of different types. With the large number of surveyed galaxies, we have studied the XLFs and ULX properties across different host galaxy types, and confirm with good statistics that the XLF slope flattens from lenticular (α ˜ 1.50 ± 0.07) to elliptical (˜1.21 ± 0.02), to spirals (˜0.80 ± 0.02), to peculiars (˜0.55 ± 0.30), and to irregulars (˜0.26 ± 0.10). The XLF break dividing the neutron star and black hole binaries is also confirmed, albeit at quite different break luminosities for different types of galaxies. A radial dependency is found for ellipticals, with a flatter XLF slope for sources located between D 25 and 2D 25, suggesting the XLF slopes in the outer region of early-type galaxies are dominated by low-mass X-ray binaries in globular clusters. This study shows that the ULX rate in early-type galaxies is 0.24 ± 0.05 ULXs per surveyed galaxy, on a 5σ confidence level. The XLF for ULXs in late-type galaxies extends smoothly until it drops abruptly around 4 × 1040 erg s-1, and this break may suggest a mild boundary between the stellar black hole population possibly including 30 M ⊙ black holes with super-Eddington radiation and intermediate mass black holes.

  18. Confronting X-Ray Emission Models with theHighest-Redshift Kiloparsec-Scale Jets: The z = 3.89 Jet in Quasar 1745+624

    SciTech Connect

    Cheung, C.C.; Stawarz, L.; Siemiginowska, A.; /Harvard-Smithsonian Ctr. Astrophys.

    2006-06-28

    A newly identified kiloparsec-scale X-ray jet in the high-redshift z=3.89 quasar 1745+624 is studied with multi-frequency Very Large Array, Hubble Space Telescope, and Chandra X-ray imaging data. This is only the third large-scale X-ray jet beyond z > 3 known and is further distinguished as being the most luminous relativistic jet observed at any redshift, exceeding 10{sup 45} erg/s in both the radio and X-ray bands. Apart from the jet's extreme redshift, luminosity, and high inferred equipartition magnetic field (in comparison to local analogues), its basic properties such as X-ray/radio morphology and radio polarization are similar to lower-redshift examples. Its resolved linear structure and the convex broad-band spectral energy distributions of three distinct knots are also a common feature among known powerful X-ray jets at lower-redshift. Relativistically beamed inverse Compton and ''non-standard'' synchrotron models have been considered to account for such excess X-ray emission in other jets; both models are applicable to this high-redshift example but with differing requirements for the underlying jet physical properties, such as velocity, energetics, and electron acceleration processes. One potentially very important distinguishing characteristic between the two models is their strongly diverging predictions for the X-ray/radio emission with increasing redshift. This is considered, though with the limited sample of three z > 3 jets it is apparent that future studies targeted at very high-redshift jets are required for further elucidation of this issue. Finally, from the broad-band jet emission we estimate the jet kinetic power to be no less than 10{sup 46} erg/s, which is about 10% of the Eddington luminosity corresponding to this galaxy's central supermassive black hole mass M{sub BH} {approx}> 10{sup 9} M{sub {circle_dot}} estimated here via the virial relation. The optical luminosity of the quasar core is about ten times over Eddington, hence the

  19. A jet emission model to probe the dynamics of accretion and ejection coupling in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Malzac, Julien

    2016-07-01

    Compact jets are probably the most common form of jets in X-ray binaries and Active Galactic Nuclei. They seem to be present in all sources in the so-called hard X-ray spectral state. They are characterised by a nearly flat Spectral Energy Distribution (SED) extending from the radio to the infrared bands. This emission is usually interpreted as partially self absorbed synchrotron emission from relativistic leptons accelerated in the jet. The observed flat spectral shape requires energy dissipation and acceleration of particules over a wide range of distances along the jet. This distributed energy dissipation is likely to be powered by internal shocks caused by fluctuations of the outflow velocity. I will discuss such an internal shock model in the context of black hole binaries. I will show that internal shocks can produce the observed SEDs and also predict a strong, wavelength dependent, variability that resembles the observed one. The assumed velocity fluctuations of the jet must originate in the accretion flow. The model thus predicts a strong connection between the observable properties of the jet in the radio to IR bands, and the variability of the accretion flow as observed in X-rays. If the model is correct, this offers a unique possibility to probe the dynamics of the coupled accretion and ejection processes leading to the formation of compact jets.

  20. High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source

    NASA Astrophysics Data System (ADS)

    Fletcher, L. B.; Zastrau, U.; Galtier, E.; Gamboa, E. J.; Goede, S.; Schumaker, W.; Ravasio, A.; Gauthier, M.; MacDonald, M. J.; Chen, Z.; Granados, E.; Lee, H. J.; Fry, A.; Kim, J. B.; Roedel, C.; Mishra, R.; Pelka, A.; Kraus, D.; Barbrel, B.; Döppner, T.; Glenzer, S. H.

    2016-11-01

    We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].

  1. The Infrared Variability of GX17+2 and Low-Mass X-ray Binary Jets

    NASA Astrophysics Data System (ADS)

    McNamara, Bernard J.; Bornak, J.; Harrison, T.; Rupen, M.

    2007-12-01

    GX17+2 is a low-mass X-ray binary. It is also classified as a Z-source since it exhibits a distinctive Z-pattern in its X-ray color-color plot. GX17+2 is located in the direction of the galactic center and is not detectable at optical wavelengths. Its emission varies by over 4 magnitudes in the infrared. A number of explanations have been advanced to explain this variabilty. Based upon KPNO and Smarts IR observations, we suggest that it arises from a sychrotron jet which is periodically visible along our line of sight. This circumstance provides a rather unique opportunity to quantify a number of jet properties such as its opening angle, the sharpness of the jet boundaries, its variability, and the infrared emission uniformity across the jet.

  2. Formation and X-ray Emission from Hot bubbles in Planetary Nebulae II. Hot bubble X-ray emission

    NASA Astrophysics Data System (ADS)

    Toalá, J. A.; Arthur, S. J.

    2016-09-01

    We present a study of the X-ray emission from numerical simulations of hot bubbles in planetary nebulae (PNe). High-resolution, two-dimensional, radiation-hydrodynamical simulations of the formation and evolution of hot bubbles in PNe, with and without thermal conduction, are used to calculate the X-ray emission and study its time-dependence and relationship to the changing stellar parameters. Instabilities in the wind-wind interaction zone produce clumps and filaments in the swept-up shell of nebular material. Turbulent mixing and thermal conduction at the corrugated interface can produce quantities of intermediate temperature and density gas between the hot, shocked wind bubble and the swept-up photoionized nebular material, which can emit in soft, diffuse X-rays. We use the CHIANTI software to compute synthetic spectra for the models and calculate their luminosities. We find that models both with conduction and those without can produce the X-ray temperatures and luminosities that are in the ranges reported in observations, although the models including thermal conduction are an order of magnitude more luminous than those without. Our results show that at early times the diffuse X-ray emission should be dominated by the contribution from the hot, shocked stellar wind, whereas at later times the nebular gas will dominate the spectrum. We analyse the effect of sampling on the resultant spectra and conclude that a minimum of 200 counts is required to reliably reproduce the spectral shape. Likewise, heavily smoothed surface-brightness profiles obtained from low-count detections of PNe do not provide a reliable description of the spatial distribution of the X-ray emitting gas.

  3. Final Report on X-ray Yields from OMEGA II Targets

    SciTech Connect

    Fournier, K B; May, M J; MacLaren, S A; Coverdale, C A; Davis, J F

    2007-06-20

    We present details about X-ray yields measured with Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL) diagnostics in soft and moderately hard X-ray bands from laser-driven, doped-aerogel targets shot on 07/14/06 during the OMEGA II test series. Yields accurate to {+-}25% in the 5-15 keV band are measured with Livermore's HENWAY spectrometer. Yields in the sub-keV to 3.2 keV band are measured with LLNL's DANTE diagnostic, the DANTE yields are accurate to 10-15%. SNL ran a PCD-based diagnostic that also measured X-ray yields in the spectral region above 4 keV, and also down to the sub-keV range. The PCD and HENWAY and DANTE numbers are compared. The time histories of the moderately hard (h{nu} > 4 keV) X-ray signals are measured with LLNL's H11 PCD, and from two SNL PCDs with comparable filtration. There is general agreement between the H11 PCD and SNL PCD measured FWHM except for two of the shorter-laser-pulse shots, which is shown not to be due to analysis techniques. The recommended X-ray waveform is that from the SNL PCD p66k10, which was recorded on a fast, high-bandwidth TDS 6804 oscilloscope. X-ray waveforms from target emission in two softer spectral bands are also shown; the X-ray emissions have increasing duration as the spectral content gets softer.

  4. Global Simulations of the Interaction of Microquasar Jets with a Stellar Wind in High-mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Yoon, D.; Heinz, S.

    2015-03-01

    Jets powered by high-mass X-ray binaries must traverse the powerful wind of the companion star. We present the first global three-dimensional simulations of jet-wind interaction in high-mass X-ray binaries. We show that the wind momentum flux intercepted by the jet can lead to significant bending of the jet and that jets propagating through a spherical wind will be bent to an asymptotic angle {{\\psi }∞ }. We derive simple expressions for {{\\psi }∞ } as a function of jet power and wind thrust. For known wind parameters, measurements of {{\\psi }∞ } can be used to constrain the jet power. In the case of Cygnus X-1, the lack of jet precession as a function of orbital phase observed by the Very Long Baseline Array can be used to put a lower limit on the jet power of {{L}jet}≳ {{10}36} ergs {{s}-1}. We further discuss the case where the initial jet is inclined relative to the binary orbital axis. We also analyze the case of Cygnus X-3 and show that jet bending is likely negligible unless the jet is significantly less powerful or much wider than currently thought. Our numerical investigation is limited to isotropic stellar winds. We discuss the possible effects of wind clumping on jet-wind interaction, which are likely significant, but argue that our limits on jet power for Cygnus X-1 are likely unaffected by clumping unless the global wind mass-loss rate is orders of magnitude below the commonly assumed range for Cyg X-1.

  5. Second Preliminary Report on X-ray Yields from OMEGA II Targets

    SciTech Connect

    Fournier, K B; May, M J; MacLaren, S A; Coverdale, C A; Davis, J F

    2006-08-28

    We present details about X-ray yields measured with LLNL and SNL diagnostics in soft and moderately hard X-ray bands from laser-driven, doped-aerogel targets shot on 07/14/06 during the OMEGA II test series. Yields accurate to {+-}25% in the 5-15 keV band are measured with Livermore's HENWAY spectrometer. Yields in the sub-keV to 3.2 keV band are measured with LLNL's DANTE diagnostic, the DANTE yields may be 35-40% too large. SNL ran a PCD-based diagnostic that also measured X-ray yields in the spectral region above 4 keV, and also down to the nearly sub-keV range. The PCD and HENWAY and DANTE numbers are compared. The time histories of the X-ray signals are measured with LLNL's H11 PCD, and from two SNL PCDs with comparable filtering. There is a persistent disagreement between the H11 PCD and SNL PCD measured FWHM, which is shown not to be due to analysis techniques. The recommended X-ray waveform is that from the SNL PCD p66k10, which was recorded on a fast, high-bandwidth TDS 6804 oscilloscope, and which are not plotted here.

  6. Long-term optical variability of high-mass X-ray binaries. II. Spectroscopy

    NASA Astrophysics Data System (ADS)

    Reig, P.; Nersesian, A.; Zezas, A.; Gkouvelis, L.; Coe, M. J.

    2016-05-01

    Context. High-mass X-ray binaries are bright X-ray sources. The high-energy emission is caused by the accretion of matter from the massive companion onto a neutron star. The accreting material comes from either the strong stellar wind in binaries with supergiant companions or the cirscumstellar disk in Be/X-ray binaries. In either case, the Hα line stands out as the main source of information about the state of the accreting material. Aims: We present the results of our monitoring program to study the long-term variability of the Hα line in high-mass X-ray binaries. Our aim is to characterise the optical variability timescales and study the interaction between the neutron star and the accreting material. Methods: We fitted the Hα line with Gaussian profiles and obtained the line parameters and equivalent width. The peak separation in split profiles was used to determine the disk velocity law and estimate the disk radius. The relative intensity of the two peaks (V/R ratio) allowed us to investigate the distribution of gas particles in the disk. The equivalent width was used to characterise the degree of variability of the systems. We also studied the variability of the Hα line in correlation with the X-ray activity. Results: Our results can be summarised as follows: i) we find that Be/X-ray binaries with narrow orbits are more variable than systems with long orbital periods; ii) we show that a Keplerian distribution of gas particles provides a good description of the disks in Be/X-ray binaries, as it does in classical Be stars; iii) a decrease in the Hα equivalent width is generally observed after major X-ray outbursts; iv) we confirm that the Hα equivalent width correlates with disk radius; v) while systems with supergiant companions display multi-structured profiles, most of the Be/X-ray binaries show, at some epoch, double-peak asymmetric profiles, which indicates that density inhomogeneities is a common property in the disk of Be/X-ray binaries; vi) the

  7. Table-top soft x-ray microscope using laser-induced plasma from a pulsed gas jet.

    PubMed

    Müller, Matthias; Mey, Tobias; Niemeyer, Jürgen; Mann, Klaus

    2014-09-22

    An extremely compact soft x-ray microscope operating in the "water window" region at the wavelength λ = 2.88 nm is presented, making use of a long-term stable and nearly debris-free laser-induced plasma from a pulsed nitrogen gas jet target. The well characterized soft x-ray radiation is focused by an ellipsoidal grazing incidence condenser mirror. Imaging of a sample onto a CCD camera is achieved with a Fresnel zone plate using magnifications up to 500x. The spatial resolution of the recorded microscopic images is about 100 nm as demonstrated for a Siemens star test pattern.

  8. Tin(II) ketoacidoximates: synthesis, X-ray structures and processing to tin(II) oxide.

    PubMed

    Khanderi, Jayaprakash; Davaasuren, Bambar; Alshankiti, Buthainah Ameen; Rothenberger, Alexander

    2015-12-14

    Tin(II) ketoacidoximates of the type [HON=CRCOO]2Sn (R = Me 1, CH2Ph 2) and (MeON=CMeCOO)3Sn](-) NH4(+)·2H2O 3 were synthesized by reacting pyruvate- and hydroxyl- or methoxylamine RONH2 (R = H, Me) with tin(II) chloride dihydrate SnCl2·2H2O. The single crystal X-ray structure reveals that the geometry at the Sn atom is trigonal bipyramidal in 1, 2 and trigonal pyramidal in 3. Inter- or intramolecular hydrogen bonding is observed in 1-3. Thermogravimetric (TG) analysis shows that the decomposition of 1-3 to SnO occurs at ca. 160 °C. The evolved gas analysis during TG indicates complete loss of the oximato ligand in one step for 1 whereas a small organic residue is additionally removed at temperatures >400 °C for 2. Above 140 °C, [HON=C(Me)COO]2Sn (1) decomposes in air to spherical SnO particles of size 10-500 nm. Spin coating of 1 on Si or a glass substrate followed by heating at 200 °C results in a uniform film of SnO. The band gap of the produced SnO film and nanomaterial was determined by diffuse reflectance spectroscopy to be in the range of 3.0-3.3 eV. X-ray photoelectron spectroscopy indicates surface oxidation of the SnO film to SnO2 in ambient atmosphere.

  9. X-ray photoelectron spectroscopy of copper(II), copper(I), and mixed valence systems.

    PubMed

    Rupp, H; Weser, U

    1976-01-01

    X-ray photoelectron spectroscopy using copper(II), copper(I) and the mixed valence Cu(II)/Cu(I) compounds was employed as a means of studying electron transfer reactions in copper proteins. The X-ray photoelectron spectra of copper(II) compounds display characteristic satellites of both variable size and resolution. Some of these satellites could be assigned to specific ligand interactions. Unlike electron paramagnetic resonance spectroscopy, the X-ray photoelectron spectroscopic measurements of copper(I) compounds allowed the unequivocal assignment of this oxidation state. No satellites at all could be detected in the Cu(I) spectra. Furthermore, established mixed valence Cu(II)/Cu(I) complexes including Cu2SO3-CuSO3-2H2O and Cu4Cl5 (ethylenediamine)2 proved essentially a mixture of distinct portions of Cu(I) and Cu(II). This indicates that both oxidation states of copper survive in such complexes. In contrast, all Cu X-ray photoelectron signals of the more tentatively described mixed valence complexes Na2Cu3S3 and the mineral covellite, CuI4CuII2(S2)2S2, could be attributed exclusively to Cu(I). In view of the known binding of copper with sulfur in many copper proteins, it was of utmost importance to study the copper-sulfur interactions. We have demonstrated the absence of Cu(II) in CuS. This indicates strong metal-induced polarization of sulfur resulting in electron transfer to copper to yield Cu(I). PMID:953045

  10. Population synthesis of accreting white dwarfs - II. X-ray and UV emission

    NASA Astrophysics Data System (ADS)

    Chen, Hai-Liang; Woods, T. E.; Yungelson, L. R.; Gilfanov, M.; Han, Zhanwen

    2015-11-01

    Accreting white dwarfs (WDs) with non-degenerate companions are expected to emit in soft X-rays and the UV, if accreted H-rich material burns stably. They are an important component of the unresolved emission of elliptical galaxies, and their combined ionizing luminosity may significantly influence the optical line emission from warm interstellar medium (ISM). In an earlier paper, we modelled populations of accreting WDs, first generating WD with main-sequence, Hertzsprung gap and red giant companions with the population synthesis code BSE, and then following their evolution with a grid of evolutionary tracks computed with MESA. Now we use these results to estimate the soft X-ray (0.3-0.7 keV), H- and He II-ionizing luminosities of nuclear burning WDs and the number of supersoft X-ray sources for galaxies with different star formation histories. For the starburst case, these quantities peak at ˜1 Gyr and decline by ˜1-3 orders of magnitude by the age of 10 Gyr. For stellar ages of ˜10 Gyr, predictions of our model are consistent with soft X-ray luminosities observed by Chandra in nearby elliptical galaxies and He II 4686 Å/H β line ratio measured in stacked Sloan Digital Sky Survey spectra of retired galaxies, the latter characterizing the strength and hardness of the UV radiation field. However, the soft X-ray luminosity and He II 4686 Å/H β ratio are significantly overpredicted for stellar ages of ≲4-8 Gyr. We discuss various possibilities to resolve this discrepancy and tentatively conclude that it may be resolved by a modification of the typically used criteria of dynamically unstable mass-loss for giant stars.

  11. A LINK BETWEEN X-RAY EMISSION LINES AND RADIO JETS IN 4U 1630-47?

    SciTech Connect

    Neilsen, Joseph; Coriat, Mickaël; Fender, Rob; Broderick, Jess W.; Lee, Julia C.; Ponti, Gabriele; Tzioumis, Anastasios K.; Edwards, Philip G.

    2014-03-20

    Recently, Díaz Trigo et al. reported an XMM-Newton detection of relativistically Doppler-shifted emission lines associated with steep-spectrum radio emission in the stellar-mass black hole candidate 4U 1630-47 during its 2012 outburst. They interpreted these lines as indicative of a baryonic jet launched by the accretion disk. Here we present a search for the same lines earlier in the same outburst using high-resolution X-ray spectra from the Chandra HETGS. While our observations (eight months prior to the XMM-Newton campaign) also coincide with detections of steep spectrum radio emission by the Australia Telescope Compact Array, we find no evidence for any relativistic X-ray emission lines. Indeed, despite ∼5 × brighter radio emission, our Chandra spectra allow us to place an upper limit on the flux in the blueshifted Fe XXVI line that is ≳ 20 × weaker than the line observed by Díaz Trigo et al. We explore several scenarios that could explain our differing results, including variations in the geometry of the jet or a mass-loading process or jet baryon content that evolves with the accretion state of the black hole. We also consider the possibility that the radio emission arises in an interaction between a jet and the nearby interstellar medium, in which case the X-ray emission lines might be unrelated to the radio emission.

  12. Emerging pictures on the disk-jet connection from simultaneous multiwavelength observations of black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Sivakoff, Gregory; Russell, David; Markoff, Sera; Miller-Jones, James; Tetarenko, Alexandra; Curran, Peter

    2016-07-01

    Relativistic jets in black hole X-ray binaries (BHXBs) are fundamentally linked to accretion onto the central black hole. Since the outbursts of X-ray binaries, stellar mass cousins of AGN, typically last weeks to months, BHXBs are ideal targets for probing the connected physics of accretion disks and jets over entire outbursts. However, this fast evolution requires coordinated multiwavelength monitoring observations to best probe this physics. The relativistic jet is typically best probed at low frequencies (radio, mm/sub-mm, mid-IR, near-IR, optical) with ground-based observatories while the accretion disk is best probed at X-ray frequencies from space-based observatories. Over the last several years stronger coordination among scientific teams and these facilities has enabled a greater number of near-simultaneous or simultaneous observations. In this talk, I use examples from a range of campaigns (e.g., MAXI J1836-194 & V404 Cyg) to discuss the gains that are being made with increasingly simultaneous observations. I highlight how four specific multi-wavelength trends (flux monitoring with high resolution imaging; dynamic nearly simultaneous SEDs; the push to mm/sub-mm frequencies; comparison of high time resolution data) are producing data that are increasingly testing theoretical models of jet production.

  13. Energy-dependent Orbital Modulation of X-rays and Constraints on Emission of the Jet in Cyg X-3

    NASA Technical Reports Server (NTRS)

    Zdziarski, Andrzej A.; Maitra, Chandreyee; Frankowski, Adam; Skinner, Gerald K.; Misra, Ranjeev

    2012-01-01

    We study orbital modulation of X-rays from Cyg X-3, using data from Swift, INTEGRAL and RXTE. Using the wealth of the presently available data and an improved averaging method, we obtain energy-dependent folded and averaged light curves with unprecedented accuracy. We find that above 5 keV, the modulation depth decreases with the increasing energy, which is consistent with the modulation being caused by both bound-free absorption and Compton scattering in the stellar wind of the donor, with minima corresponding to the highest optical depth, which occurs around the superior conjunction. We find a decrease of the depth below 3 keV, which appears to be due to re-emission of the absorbed continuum by the wind in soft X-ray lines. Based on the shape of the folded light curves, any X-ray contribution from the jet in Cyg X-3, which emits ?-rays detected at energies > 0.1 GeV in soft spectral states, is found to be minor up to 100 keV. This implies the presence of a rather sharp low-energy break in the jet MeV-range spectrum.We also calculate phase-resolved RXTE X-ray spectra, and show the difference between the spectra corresponding to phases around the superior and inferior conjunctions can indeed be accounted for by a combined effect of bound-free absorption in an ionized medium and Compton scattering.

  14. A Radio through X-Ray Study of the Hot Spots, Active Nucleus, and Environment of the Nearby FR II Radio Galaxy 3C 33

    NASA Astrophysics Data System (ADS)

    Kraft, R. P.; Birkinshaw, M.; Hardcastle, M. J.; Evans, D. A.; Croston, J. H.; Worrall, D. M.; Murray, S. S.

    2007-04-01

    We present results from Chandra ACIS-S, Spitzer, XMM-Newton, HST, and VLA observations of the radio hot spots, extended environment, and nucleus of the nearby (z=0.0597) FR II radio galaxy 3C 33. This is a relatively low power FR II radio galaxy, so we expect, a priori, to detect a significant X-ray synchrotron component to the emission from the hot spots. We detect X-ray emission coincident with the two knots of polarized optical emission from the southern hot spot (SHS), as well as along the northwest arm of this hot spot. We also detect X-ray emission from two compact regions of the northern hot spot (NHS), as well as diffuse emission behind the radio peak. The X-ray flux density of the region at the tip of the southern hot spot, the most compact radio feature of the southern lobe, is consistent with the synchrotron self-Compton (SSC) process. The X-ray flux densities of the other three regions of the SHS and the two compact regions of the NHS are an order of magnitude or more above the predictions from either the SSC or inverse Compton scattering of the CMB (IC/CMB) mechanisms, thus strongly disfavoring these scenarios unless they are far from equipartition (B~4-14 times smaller than the equipartition values). We conclude that the X-ray emission is synchrotron emission from multiple populations of ultrarelativistic electrons. There must be complex, unresolved substructure within each region. The detection of X-ray emission from both hot spots combined with the large absorbing column toward the primary power-law component of the nucleus conclusively demonstrate that the jets must lie relatively close to the plane of the sky and that relativistic beaming cannot be important.

  15. Large-area x-ray topographic screening of II-VI substrates and epilayers

    NASA Astrophysics Data System (ADS)

    Di Marzio, Don; Larson, David J., Jr.; Casagrande, Louis G.; Wu, Jun; Dudley, Michael; Tobin, Stephen P.; Norton, Peter W.

    1994-07-01

    A crucial aspect of process control in II-VI based device fabrication is the detailed monitoring of material properties, particularly structural quality. We have developed a method of mapping structural defects over large wafer areas using synchrotron white beam x-ray topography and have used it to characterize large area single crystal CdZnTe substrates and LPE HgCdTe epilayers grown on them. The synchrotron white beam technique produces high resolution topographic images of whole wafers regardless of long range strain, and the multiple images generated as a result of the polychromatic white beam (Laue geometry) provide an automatic defect depth profiling. The topographs reveal various types of defect structure in the CdZnTe substrates, and we have compared these topographic images to IR micrographs and x-ray rocking curve maps. Defect structures as revealed by the x-ray topographs were then followed from the CdZnTe substrates to the LPE grown HgCdTe epilayers. Epilayer topographs were also compared to conventional optical micrographs as well as with x-ray rocking curve maps. Finally, a scanning stage was constructed to topographically image large wafers and boule slabs.

  16. A comparative study of local galaxy clusters - II. X-ray and SZ scaling relations

    NASA Astrophysics Data System (ADS)

    Rozo, E.; Evrard, A. E.; Rykoff, E. S.; Bartlett, J. G.

    2014-02-01

    We compare cluster scaling relations published for three different samples selected via X-ray and Sunyaev-Zel'dovich (SZ) signatures. We find tensions driven mainly by two factors: (i) systematic differences in the X-ray cluster observables used to derive the scaling relations and (ii) uncertainty in the modelling of how the gas mass of galaxy clusters scales with total mass. All scaling relations are in agreement after accounting for these two effects. We describe a multivariate scaling model that enables a fully self-consistent treatment of multiple observational catalogues in the presence of property covariance and apply this formalism when interpreting published results. The corrections due to scatter and observable covariance can be significant. For instance, our predicted YSZ-LX scaling relation differs from that derived using the naive `plug in' method by ≈25 per cent. Finally, we test the mass normalization for each of the X-ray data sets we consider by applying a space density consistency test: we compare the observed ROSAT-ESO Flux-Limited X-ray (REFLEX) luminosity function to expectations from published LX-M relations convolved with the mass function for a Wilkinson Microwave Anisotropy Probe 7 flat Λ cold dark matter model.

  17. Connection Between X-Ray Emission and Relativistic Jets in the Radio Galaxies 3C 111 and 3C 120

    NASA Technical Reports Server (NTRS)

    Aller, Margo F.

    2005-01-01

    This work represents a part of a longterm study of the X-ray flux variability in radio galaxies and its relation to flux and structural changes in the associated radio jet. The work described here included: 1) continued study of the emission properties of the FR I radio galaxy 3C 120 known to exhibit a jet/disk connection from our past work; and 2) the commencement of monitoring of a second radio galaxy, the FR I1 object 3C 111 which was selected because of similar radio and X-ray properties to 3C 120, including the presence of Fe K a emission. The association between X-ray dips and new superluminal components, suggesting a picture in which the radio jet is fed by accretion events near the black hole, was identified in 3C 120 using combined RXTE and radio flux monitoring data and bi-monthly to monthly imaging data from the VLBA at 43 GHz. Such data were also obtained for both targets during the period described here. Specific goals were to more broadly investigate the X-ray dip/superluminal connection in 3C 120, thereby determining the epochs of X-ray minima and superluminal ejections more accurately (and hence more precisely determining the distance between the accretion disk and the core of the radio jet), and to determine whether a similar pattern is present in the data for a second radio galaxy. In 3C 111 a different time scale (longer time delays between X-ray dips and superluminal ejections) was expected due to the higher black hole mass implied by its higher radio luminosity: no black hole mass is published for this object but one can be determined from a PDS analysis of the RXTE data. The addition of the second source to the study would identify whether a similar connection was present in other sources and, if found, would provide important information on how time scale (and hence size scale) of accretion disk/jet systems depends on black hole mass. The grant included funding for the reduction and analysis of data obtained during the time period of Rossi

  18. Optical and X-ray properties of CAL 83 - II. An X-ray pulsation at ˜67 s

    NASA Astrophysics Data System (ADS)

    Odendaal, A.; Meintjes, P. J.; Charles, P. A.; Rajoelimanana, A. F.

    2014-01-01

    CAL 83 is the prototypical close binary supersoft X-ray source in the Large Magellanic Cloud, has a 1 d orbital period, and is believed to consist of a white dwarf (WD) primary accreting from an evolved donor. Based on published WD model atmosphere fits to X-ray data, the WD has a mass of ˜1.3 M⊙, just below the Chandrasekhar limit. From a systematic search through archival XMM-Newton data for periodic emission from CAL 83 down to the shortest possible period just above the WD break-up period, we report the discovery of an ˜67 s supersoft X-ray modulation, which we interpret as the rotation period of a highly spun-up WD. Such a short period can be explained within the framework of a high mass accretion history, where accretion disc torques could have spun up the WD over time-scales comparable to the thermal time-scale. The presence of carbon, oxygen and nitrogen in published optical and ultraviolet spectra may suggest CNO cycling in the envelope of a secondary star that is oversized for its inferred mass, suggesting that the secondary star shed a significant fraction of its envelope during a high mass-transfer history, resulting in a highly spun-up WD. The reported 67 s period shows an approximately ±3 s drift from the median value in single runs, which we interpret as a hydrogen burning gas envelope surrounding the WD, with a period not quite synchronized with the WD rotation period.

  19. Guitar with a bow: a jet-like X-ray-emitting feature associated a fast-moving pulsar

    NASA Astrophysics Data System (ADS)

    Wang, Q. Daniel

    2011-09-01

    The Guitar Nebula is known to be a ram-pressure confined pulsar wind nebula associated with the very fast-moving pulsar B2224+65. Existing observations at two epochs have shown an unexpected 2 arcmin long X-ray-emitting jet-like feature emanating from the pulsar and offset from its proper motion direction by 118 degree. We propose a deep third epoch observation of this system in order to measure the X-ray spectral gradient across the feature as well as to confirm its proper motion, its morphological variation with time, and the presence of a counter jet. We will then critically test scenarios proposed to explain this system, which represents a class of similarly enigmatic objects recently discovered locally and in the central region of our Galaxy.

  20. Achieving Vibration Stability of the NSLS-II Hard X-ray Nanoprobe Beamline

    SciTech Connect

    Simos, N.; Chu, Y. S.; Broadbent, A.; Nazaretski, E.; Margulies, L.; Dyling, O.; Shen, Q.; Fallier, M.

    2011-09-09

    The hard x-ray nanoprobe (HXN) beamline of the National Synchrotron Light Source II (NSLS-II) requires high levels of stability in order to achieve the desired instrument resolution. To ensure that the design of the endstation helps meet the stringent criteria and that natural and cultural vibration is mitigated both passively and actively, a comprehensive study complimentary to the design process has been undertaken. Vibration sources that have the potential to disrupt sensitive experiments such as wind, traffic, and NSLS II operating systems have been studied using state-of-the-art simulations and an array of field data. Further, final stage vibration isolation principles have been explored.

  1. X-RAY AND GAMMA-RAY POLARIZATION IN LEPTONIC AND HADRONIC JET MODELS OF BLAZARS

    SciTech Connect

    Zhang, H.; Boettcher, M.

    2013-09-01

    We present a theoretical analysis of the expected X-ray and {gamma}-ray polarization signatures resulting from synchrotron self-Compton emission in leptonic models compared to the polarization signatures from proton synchrotron and cascade synchrotron emission in hadronic models for blazars. Source parameters resulting from detailed spectral-energy-distribution modeling are used to calculate photon-energy-dependent upper limits on the degree of polarization, assuming a perfectly organized mono-directional magnetic field. In low-synchrotron-peaked blazars, hadronic models exhibit substantially higher maximum degrees of X-ray and gamma-ray polarization than leptonic models, which may be within reach of existing X-ray and {gamma}-ray polarimeters. In high-synchrotron-peaked blazars (with electron-synchrotron-dominated X-ray emission), leptonic and hadronic models predict the same degree of X-ray polarization but substantially higher maximum {gamma}-ray polarization in hadronic models than leptonic ones. These predictions are particularly relevant in view of the new generation of balloon-borne X-ray polarimeters (and possibly GEMS, if revived), and the ability of Fermi-LAT to measure {gamma}-ray polarization at <200 MeV. We suggest observational strategies combining optical, X-ray, and {gamma}-ray polarimetry to determine the degree of ordering of the magnetic field and to distinguish between leptonic and hadronic high-energy emissions.

  2. FRAME DRAGGING, DISK WARPING, JET PRECESSING, AND DIPPED X-RAY LIGHT CURVE OF Sw J1644+57

    SciTech Connect

    Lei, Wei-Hua; Zhang, Bing; Gao, He E-mail: zhang@physics.unlv.edu

    2013-01-10

    The X-ray transient source Sw J1644+57 recently discovered by Swift is believed to be triggered by tidal disruption of a star by a rapidly spinning supermassive black hole (SMBH). For such events, the outer disk is very likely misaligned with respect to the equatorial plane of the spinning SMBH, since the incoming star before disruption most likely has an inclined orbital plane. The tilted disk is subject to the Lense-Thirring torque, which tends to twist and warp due to the Bardeen-Petterson effect. The inner disk tends to align with the SMBH spin, while the outer region tends to remain in the stellar orbital plane, with a transition zone around the Bardeen-Petterson radius. The relativistic jet launched from the spinning SMBH would undergo precession. The 5-30 day X-ray light curve of Sw J1644+57 shows a quasi-periodic (2.7 day) variation with noticeable narrow dips. We numerically solve a warped disk and propose a jet-precessing model by invoking a Blandford-Znajek jet collimated by a wind launched near the Bardeen-Petterson radius. Through simulations, we show that the narrow dips in the X-ray light curve can be reproduced for a range of geometric configurations. From the data we infer that the inclination angle of the initial stellar orbit is in the range of 10 Degree-Sign -20 Degree-Sign from the SMBH equatorial plane, that the jet should have a moderately high Lorentz factor, and that the inclination angle, jet opening angle, and observer's viewing angle are such that the duty cycle of the line of sight sweeping the jet cone is somewhat less than 0.5.

  3. Frame Dragging, Disk Warping, Jet Precessing, and Dipped X-Ray Light Curve of Sw J1644+57

    NASA Astrophysics Data System (ADS)

    Lei, Wei-Hua; Zhang, Bing; Gao, He

    2013-01-01

    The X-ray transient source Sw J1644+57 recently discovered by Swift is believed to be triggered by tidal disruption of a star by a rapidly spinning supermassive black hole (SMBH). For such events, the outer disk is very likely misaligned with respect to the equatorial plane of the spinning SMBH, since the incoming star before disruption most likely has an inclined orbital plane. The tilted disk is subject to the Lense-Thirring torque, which tends to twist and warp due to the Bardeen-Petterson effect. The inner disk tends to align with the SMBH spin, while the outer region tends to remain in the stellar orbital plane, with a transition zone around the Bardeen-Petterson radius. The relativistic jet launched from the spinning SMBH would undergo precession. The 5-30 day X-ray light curve of Sw J1644+57 shows a quasi-periodic (2.7 day) variation with noticeable narrow dips. We numerically solve a warped disk and propose a jet-precessing model by invoking a Blandford-Znajek jet collimated by a wind launched near the Bardeen-Petterson radius. Through simulations, we show that the narrow dips in the X-ray light curve can be reproduced for a range of geometric configurations. From the data we infer that the inclination angle of the initial stellar orbit is in the range of 10°-20° from the SMBH equatorial plane, that the jet should have a moderately high Lorentz factor, and that the inclination angle, jet opening angle, and observer's viewing angle are such that the duty cycle of the line of sight sweeping the jet cone is somewhat less than 0.5.

  4. Production and X-ray crystallographic analysis of fully deuterated human carbonic anhydrase II

    SciTech Connect

    Budayova-Spano, Monika; Fisher, S. Zoë; Dauvergne, Marie-Thérèse; Agbandje-McKenna, Mavis; Silverman, David N.; Myles, Dean A. A.; McKenna, Robert

    2006-01-01

    This article reports the production, crystallization and X-ray structure determination of perdeuterated human carbonic anhydrase (HCA II). The refined structure is shown to be highly isomorphous with hydrogenated HCA II, especially with regard to the active site architecture and solvent network. Human carbonic anhydrase II (HCA II) is a zinc metalloenzyme that catalyzes the reversible hydration and dehydration of carbon dioxide and bicarbonate, respectively. The rate-limiting step in catalysis is the intramolecular transfer of a proton between the zinc-bound solvent (H{sub 2}O/OH{sup −}) and the proton-shuttling residue His64. This distance (∼7.5 Å) is spanned by a well defined active-site solvent network stabilized by amino-acid side chains (Tyr7, Asn62, Asn67, Thr199 and Thr200). Despite the availability of high-resolution (∼1.0 Å) X-ray crystal structures of HCA II, there is currently no definitive information available on the positions and orientations of the H atoms of the solvent network or active-site amino acids and their ionization states. In preparation for neutron diffraction studies to elucidate this hydrogen-bonding network, perdeuterated HCA II has been expressed, purified, crystallized and its X-ray structure determined to 1.5 Å resolution. The refined structure is highly isomorphous with hydrogenated HCA II, especially with regard to the active-site architecture and solvent network. This work demonstrates the suitability of these crystals for neutron macromolecular crystallography.

  5. The extended ROSAT-ESO Flux Limited X-ray Galaxy Cluster Survey (REFLEX II). IV. X-ray luminosity function and first constraints on cosmological parameters

    NASA Astrophysics Data System (ADS)

    Böhringer, Hans; Chon, Gayoung; Collins, Chris A.

    2014-10-01

    The X-ray luminosity function that is closely related to the cluster mass function is an important statistic of the census of galaxy clusters in our Universe. It is also an important means to probe the cosmological model of our Universe. Based on our recently completed REFLEX II cluster sample comprising 910 galaxy clusters with redshifts we construct the X-ray luminosity function of galaxy clusters for the nearby Universe and discuss its implications. We derived the X-ray luminosity function of the REFLEX II clusters on the basis of a precisely constructed selection function for the full sample and for several redshift slices from z = 0 to z = 0.4. In this redshift interval we find no significant signature of redshift evolution of the luminosity function. We provide the results of fits of a parameterized Schechter function and extensions of it which provide a reasonable characterization of the data. We also use a model for structure formation and galaxy cluster evolution to compare the observed X-ray luminosity function with the theoretical predictions for different cosmological models. The most interesting constraints can be derived for the cosmological parameters Ωm and σ8. We explore the influence of several model assumptions on which our analysis is based. We find that the scaling relation of X-ray luminosity and mass introduces the largest systematic uncertainty. From the statistical uncertainty alone we can constrain the matter density parameter, Ωm ~ 0.27 ± 0.03 and the amplitude parameter of the matter density fluctuations, σ8 ~ 0.80 ± 0.03. Marginalizing over the most important uncertainties, the normalisation and slope of the LX - M scaling relation, we have larger error bars and a result of Ωm ~ 0.29 ± 0.04 and σ8 ~ 0.77 ± 0.07 (1σ confidence limits). We compare our results with those of the SZ-cluster survey provided by the Planck mission and we find very good agreement with the results using Planck clusters as cosmological probes, but there

  6. Performance of water jet cooled silicon monochromators in high power x-ray beams (abstract)

    NASA Astrophysics Data System (ADS)

    Berman, Lonny E.; Hart, Michael

    1992-01-01

    We have fabricated and tested water jet cooled silicon (111) and (220) monochromators specially tailored for extended wiggler beam and concentrated undulator beam power loadings. The tests were made at the X25 27 pole, 1.1 T hybrid wiggler beam line1 at the National Synchrotron Light Source (NSLS). The wiggler-like line-type loading was produced by the direct, unfocused wiggler white beam, in which 300 W of total power in a 60-mm-wide by 5-mm-high [full width at half maximum (FWHM)] cross section were available in the experimental hutch; this represents a typical power density at existing insertion device beam lines. The undulator-like point-type loading was produced by the focused wiggler white beam, generated via reflection of a portion of the direct white beam from a toroidal platinum-coated silicon mirror, resulting in 75 W of total power in a 0.8-mm-wide (FWHM) by 0.45-mm-high (FWHM) cross section in the hutch. This will be a typical power density at next-generation insertion device beam lines. The monochromator design consists of a thin walled silicon box whose bottom is glued to a stainless-steel water manifold; the coolant is delivered through jet tubes directed perpendicular to the underside of the top, diffracting surface of the box.2 Rectangular monochromators with multiple jets were used for the line power loading studies, and cylindrical monochromators with single jets were used for the point power loading studies. Provisions for simple adaptive corrections to compensate for the inevitable beam-induced thermal deformations, consisting of mechanisms to reverse-bend the top surface, and internal heat baffles to frustrate the cooling at the edges of the crystal (to produce an isothermal top surface), were included in the designs. These required approximate matching of the top surface dimensions to the x-ray footprint. To better understand the thermal strain fields, spatial and angular mapping of both fundamental and harmonic Bragg reflections within the

  7. Detailed Structure of the X-Ray Jet in 4C 19.44 (=PKS1354+195)

    SciTech Connect

    Schwartz, Daniel A.; Harris, D.E.; Landt, H.; Siemiginowska, A.; Perlman, E.S.; Cheung, C.C.; Gelbord, J.M.; Worrall, D.M.; Birkinshaw, M.; Jorstad, S.G.; Marscher, A.P.; Stawarz, L.; /KIPAC, Menlo Park

    2006-10-31

    We investigate the variations of the magnetic field, Doppler factor, and relativistic particle density along the jet of a quasar at z=0.72. We chose 4C 19.44 for this study because of its length and straight morphology. The 18 arcsec length of the jet provides many independent resolution elements in the Chandra X-ray image. The straightness suggests that geometry factors, although uncertain, are almost constant along the jet. We assume the X-ray emission is from inverse Compton scattering of the cosmic microwave background. With the aid of assumptions about jet alignment, equipartition between magnetic-field and relativistic-particle energy, and filling factors, we find that the jet is in bulk relativistic motion with a Doppler factor {approx} 6 at an angle no more than 10{sup o} to the line of sight over deprojected distances {approx} 150-600 kpc from the quasar, and with a magnetic field {approx} 10 {micro}Gauss.

  8. Clumpy tori around type II active galactic nuclei as revealed by X-ray fluorescent lines

    NASA Astrophysics Data System (ADS)

    Liu, Jiren; Liu, Yuan; Li, Xiaobo; Xu, Weiwei; Gou, Lijun; Cheng, Cheng

    2016-06-01

    The reflection spectrum of a torus around an active galactic nucleus (AGN) is characterized by X-ray fluorescent lines, which are most prominent for type II AGNs. A clumpy torus allows photons reflected from the back-side of the torus to leak through the front regions that are free of obscuration. The observed X-ray fluorescent lines are therefore sensitive to the clumpiness of the torus. We analysed a sample of type II AGNs observed with the Chandra High Energy Transmission Grating Spectrometer (HETGS), and measured the fluxes for the Si Kα and Fe Kα lines. The measured Fe Kα/Si Kα ratios, spanning a range between 5 and 60, are far smaller than the ratios predicted from simulations of smooth tori, indicating that the tori of the studied sources have clumpy distributions rather than smooth ones. We compared the measured Fe Kα/Si Kα ratios with simulation results of clumpy tori. The Circinus galaxy has a Fe Kα/Si Kα ratio of ˜60, which is close to the simulation results for N = 5, where N is the average number of clumps along the line of sight. The Fe Kα/Si Kα ratios of the other sources are all below the simulation results for N = 2. Overall, this shows that the non-Fe fluorescent lines in the soft X-ray band are a potentially powerful probe of the clumpiness of tori around AGNs.

  9. CHANDRA AND HST IMAGING OF THE QUASARS PKS B0106+013 AND 3C 345: INVERSE COMPTON X-RAYS AND MAGNETIZED JETS

    SciTech Connect

    Kharb, P.; Lister, M. L.; Hogan, B. S.; Marshall, H. L.

    2012-04-01

    We present results from deep ({approx}70 ks) Chandra/ACIS observations and Hubble Space Telescope (HST) Advanced Camera for Surveys F475W observations of two highly optically polarized quasars belonging to the MOJAVE blazar sample, viz., PKS B0106+013 and 1641+399 (3C 345). These observations reveal X-ray and optical emissions from the jets in both sources. X-ray emission is detected from the entire length of the 0106+013 radio jet, which shows clear bends or wiggles-the X-ray emission is brightest at the first prominent kiloparsec jet bend. A picture of a helical kiloparsec jet with the first kiloparsec-scale bend representing a jet segment moving close(r) to our line of sight, and getting Doppler boosted at both radio and X-ray frequencies, is consistent with these observations. The X-ray emission from the jet end, however, peaks at about 0.''4 ({approx}3.4 kpc) upstream of the radio hot spot. Optical emission is detected both at the X-ray jet termination peak and at the radio hot spot. The X-ray jet termination peak is found upstream of the radio hot spot by around 0.''2 ({approx}1.3 kpc) in the short projected jet of 3C 345. HST optical emission is seen in an arc-like structure coincident with the bright radio hot spot, which we propose is a sharp (apparent) jet bend instead of a terminal point, that crosses our line of sight and consequently has a higher Doppler beaming factor. A weak radio hot spot is indeed observed less than 1'' downstream of the bright radio hot spot, but has no optical or X-ray counterpart. By making use of the parsec-scale radio and the kiloparsec-scale radio/X-ray data, we derive constraints on the jet Lorentz factors ({Gamma}{sub jet}) and inclination angles ({theta}): for a constant jet speed from parsec to kiloparsec scales, we obtain a {Gamma}{sub jet} of {approx}70 for 0106+013 and {approx}40 for 3C 345. On relaxing this assumption, we derive a {Gamma}{sub jet} of {approx}2.5 for both the sources. Upper limits on {theta} of {approx

  10. The life science X-ray scattering beamline at NSLS-II

    SciTech Connect

    DiFabio, Jonathan; Yang, Lin; Chodankar, Shirish; Pjerov, Sal; Jakoncic, Jean; Lucas, Michael; Krywka, Christina; Graziano, Vito

    2015-09-30

    We report the current development status of the High Brightness X-ray Scattering for Life Sciences (or Life Science X-ray Scattering, LiX) beamline at the NSLS-II facility of Brookhaven National Laboratory. This instrument will operate in the x-ray energy range of 2.1-18 keV, provide variable beam sizes from 1 micron to ~0.5 mm, and support user experiments in three scientific areas: (1) high-throughput solution scattering, in-line size exclusion chromatography and flow mixers-based time-resolved solution scattering of biological macro-molecules, (2) diffraction from single- and multi-layered lipid membranes, and (3) scattering-based scanning probe imaging of biological tissues. In order to satisfy the beam stability required for these experiments and to switch rapidly between different types of experiments, we have adopted a secondary source with refractive lenses for secondary focusing, a detector system consisting of three Pilatus detectors, and specialized experimental modules that can be quickly exchanged and each dedicated to a defined set of experiments. The construction of this beamline is on schedule for completion in September 2015. User experiments are expected to start in Spring 2016.

  11. The life science X-ray scattering beamline at NSLS-II

    DOE PAGES

    DiFabio, Jonathan; Yang, Lin; Chodankar, Shirish; Pjerov, Sal; Jakoncic, Jean; Lucas, Michael; Krywka, Christina; Graziano, Vito

    2015-09-30

    We report the current development status of the High Brightness X-ray Scattering for Life Sciences (or Life Science X-ray Scattering, LiX) beamline at the NSLS-II facility of Brookhaven National Laboratory. This instrument will operate in the x-ray energy range of 2.1-18 keV, provide variable beam sizes from 1 micron to ~0.5 mm, and support user experiments in three scientific areas: (1) high-throughput solution scattering, in-line size exclusion chromatography and flow mixers-based time-resolved solution scattering of biological macro-molecules, (2) diffraction from single- and multi-layered lipid membranes, and (3) scattering-based scanning probe imaging of biological tissues. In order to satisfy the beammore » stability required for these experiments and to switch rapidly between different types of experiments, we have adopted a secondary source with refractive lenses for secondary focusing, a detector system consisting of three Pilatus detectors, and specialized experimental modules that can be quickly exchanged and each dedicated to a defined set of experiments. The construction of this beamline is on schedule for completion in September 2015. User experiments are expected to start in Spring 2016.« less

  12. DISCOVERY OF A WANDERING RADIO JET BASE AFTER A LARGE X-RAY FLARE IN THE BLAZAR MARKARIAN 421

    SciTech Connect

    Niinuma, K.; Kino, M.; Doi, A.; Hada, K.; Nagai, H.; Koyama, S.

    2015-07-01

    We investigate the location of the radio jet bases (“radio cores”) of blazars in radio images and their stationarity by means of dense very long baseline interferometry (VLBI) observations. In order to measure the position of a radio core, we conducted a 12 epoch astrometric observation of the blazar Markarian 421 with the VLBI Exploration of Radio Astrometry at 22 GHz immediately after a large X-ray flare, which occurred in the middle of 2011 September. For the first time,we find that the radio core is not stationary but rather changes its location toward 0.5 mas downstream. This angular scale corresponds to the de-projected length of a scale of 10{sup 5} Schwarzschild radii (R{sub s}) at the distance of Markarian 421. This radio-core wandering may be a new type of manifestation associated with the phenomena of large X-ray flares.

  13. THE CHANDRA SURVEY OF EXTRAGALACTIC SOURCES IN THE 3CR CATALOG: X-RAY EMISSION FROM NUCLEI, JETS, AND HOTSPOTS IN THE CHANDRA ARCHIVAL OBSERVATIONS

    SciTech Connect

    Massaro, F.; Harris, D. E.; Paggi, A.; Wilkes, B. J.; Kuraszkiewicz, J.; Liuzzo, E.; Orienti, M.; Paladino, R.; Tremblay, G. R.; Baum, S. A.; O’Dea, C. P.

    2015-09-15

    As part of our program to build a complete radio and X-ray database of all Third Cambridge catalog extragalactic radio sources, we present an analysis of 93 sources for which Chandra archival data are available. Most of these sources have already been published. Here we provide a uniform re-analysis and present nuclear X-ray fluxes and X-ray emission associated with radio jet knots and hotspots using both publicly available radio images and new radio images that have been constructed from data available in the Very Large Array archive. For about 1/3 of the sources in the selected sample, a comparison between the Chandra and radio observations was not reported in the literature: we find X-ray detections of 2 new radio jet knots and 17 hotspots. We also report the X-ray detection of extended emission from the intergalactic medium for 15 galaxy clusters.

  14. X-Ray Reflected Spectra from Accretion Disk Models. II. Diagnostic Tools for X-Ray Observations

    NASA Technical Reports Server (NTRS)

    Garcia, J.; Kallman, T. R.; Mushotzky, R. F.

    2011-01-01

    We present a comprehensive study of the emission spectra from accreting sources. We use our new reflection code to compute the reflected spectra from an accretion disk illuminated by X-rays. This set of models covers different values of ionization parameter, solar iron abundance and photon index for the illuminating spectrum. These models also include the most complete and recent atomic data for the inner-shell of the iron and oxygen isonuclear sequences. We concentrate our analysis to the 2 - 10 keV energy region, and in particular to the iron K-shell emission lines. We show the dependency of the equivalent width (EW) of the Fe Ka with the ionization parameter. The maximum value of the EW is approx. 800 eV for models with log Epsilon approx. 1.5, and decreases monotonically as Epsilon increases. For lower values of Epsilon the Fe K(alpha) EW decreases to a minimum near log Epsilon approx. 0.8. We produce simulated CCD observations based on our reflection models. For low ionized, reflection dominated cases, the 2 -10 keV energy region shows a very broad, curving continuum that cannot be represented by a simple power-law. We show that in addition to the Fe K-shell emission, there are other prominent features such as the Si and S L(alpha) lines, a blend of Ar VIII-XI lines, and the Ca x K(alpha) line. In some cases the S xv blends with the He-like Si RRC producing a broad feature that cannot be reproduced by a simple Gaussian profile. This could be used as a signature of reflection.

  15. Analysis of the optical design of the NSLS-II coherent hard x-ray beamline

    NASA Astrophysics Data System (ADS)

    Fluerasu, Andrei; Chubar, Oleg; Kaznatcheev, Konstantine; Baltser, Jana; Wiegart, Lutz; Evans-Lutterodt, Kenneth; Carlucci-Dayton, Mary; Berman, Lonny

    2011-09-01

    Ultra-low emittance third-generation synchrotron radiation sources such as the NSLS-II offer excellent opportunities for the development of experimental techniques exploiting x-ray coherence. Coherent light scattered by a heterogeneous sample produces a speckle pattern characteristic for the specific arrangement of the scatterers. This may vary over time, and the resultant intensity fluctuations can be measured and analyzed to provide information about the sample dynamics. X-ray photon correlation spectroscopy (XPCS) extends the capability of dynamic light scattering to opaque and turbid samples and extends the measurements of time evolution to nanometer length scales. As a consequence XPCS became crucial in the study of dynamics in systems including, but not being limited to, colloids, polymers, complex fluids, surfaces and interfaces, phase ordering alloys, etc. In this paper we present the conceptual optical design and the theoretical performance of the Coherent Hard X-ray (CHX) beamline at NSLS-II, dedicated to XPCS and other coherent scattering techniques. For the optical design of this beamline, there is a tradeoff between the coherence needed to distinguish individual speckles and the phase acceptance (high intensity) required to measure fast dynamics with an adequate signal-to-noise level. As XPCS is a "photon hungry" technique, the beamline optimization requires maximizing the signal-to-noise ratio of the measured intensity-intensity autocorrelation function. The degree of coherence, as measured by a two-slit (Young) experiment, is used to characterize the speckle pattern visibilities. The beamline optimization strategy consists of maximization of the on-sample intensity while keeping the degree of coherence within the 0.1-0.5 range. The resulted design deviates substantially from an ad-hoc modification of a hard x-ray beamline for XPCS measurements. The CHX beamline will permit studies of complex systems and measurements of bulk dynamics down to the

  16. Analysis of the optical design of the NSLS-II Coherent Hard X-ray beamline

    SciTech Connect

    Fluerasu A.; Chubar, O.; Kaznatcheev, K.; Baltser, J.; Wiegart, Lutz; Evans-Lutterodt, K.; Carlucci-Dayton, M.; Berman, L.

    2011-08-21

    Ultra-low emittance third-generation synchrotron radiation sources such as the NSLS-II offer excellent opportunities for the development of experimental techniques exploiting x-ray coherence. Coherent light scattered by a heterogeneous sample produces a speckle pattern characteristic for the specific arrangement of the scatterers. This may vary over time, and the resultant intensity fluctuations can be measured and analyzed to provide information about the sample dynamics. X-ray photon correlation spectroscopy (XPCS) extends the capability of dynamic light scattering to opaque and turbid samples and extends the measurements of time evolution to nanometer length scales. As a consequence XPCS became crucial in the study of dynamics in systems including, but not being limited to, colloids, polymers, complex fluids, surfaces and interfaces, phase ordering alloys, etc. In this paper we present the conceptual optical design and the theoretical performance of the Coherent Hard X-ray (CHX) beamline at NSLS-II, dedicated to XPCS and other coherent scattering techniques. For the optical design of this beamline, there is a tradeoff between the coherence needed to distinguish individual speckles and the phase acceptance (high intensity) required to measure fast dynamics with an adequate signal-to-noise level. As XPCS is a 'photon hungry' technique, the beamline optimization requires maximizing the signal-to-noise ratio of the measured intensity-intensity autocorrelation function. The degree of coherence, as measured by a two-slit (Young) experiment, is used to characterize the speckle pattern visibilities. The beamline optimization strategy consists of maximization of the on-sample intensity while keeping the degree of coherence within the 0.1-0.5 range. The resulted design deviates substantially from an ad-hoc modification of a hard x-ray beamline for XPCS measurements. The CHX beamline will permit studies of complex systems and measurements of bulk dynamics down to the

  17. AN EVOLVING COMPACT JET IN THE BLACK HOLE X-RAY BINARY MAXI J1836-194

    SciTech Connect

    Russell, D. M.; Russell, T. D.; Miller-Jones, J. C. A.; Soria, R.; Slaven-Blair, T.; Curran, P. A.; O'Brien, K.; Sivakoff, G. R.; Lewis, F.; Markoff, S.; Altamirano, D.; Homan, J.; Rupen, M. P.; Dhawan, V.; Belloni, T. M.; Cadolle Bel, M.; Casella, P.; Corbel, S.; Gallo, E.; and others

    2013-05-10

    We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836-194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The optical-IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law, we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from {approx}10{sup 11} to {approx}4 Multiplication-Sign 10{sup 13} Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high-energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet. This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced, and hence their launching process.

  18. A MODEL FOR EMISSION FROM JETS IN X-RAY BINARIES: CONSEQUENCES OF A SINGLE ACCELERATION EPISODE

    SciTech Connect

    Pe'er, Asaf; Casella, Piergiorgio

    2009-07-10

    There is strong evidence for powerful jets in the low/hard state of black hole X-ray binaries (BHXRBs). Here, we present a model in which electrons are accelerated once at the base of the jet, and are cooled by synchrotron emission and possible adiabatic energy losses. The accelerated electrons assume a Maxwellian distribution at low energies and possible energetic power-law tail. These assumptions yield a wealth of spectra, which we study in detail. We identify critical values of the magnetic field, and five transition frequencies in the spectra. In particular, we show that (1) for wide jets, the decay of the magnetic field along the jet enables the production of flat radio spectra without the need for electron re-acceleration along the jet; (2) an increase in the magnetic field above a critical value of {approx}10{sup 5} G leads to a sharp decrease in the flux at the radio band, while the flux at higher frequencies saturates to a constant value; (3) for a strong magnetic field, the flux decays in the optical/UV band as F {sub {nu}} {proportional_to} {nu}{sup -1/2}, irrespective of the electrons' initial distribution; (4) for B{sub 0} {approx} 10{sup 4} G, the X-ray flux gradually steepens; (5) with adiabatic energy losses, flat spectrum can be obtained only at a limited frequency range, and under certain conditions; and (6) for narrow jets, r(x) {proportional_to} x {sup {alpha}} with {alpha} < 1/2, flat radio spectrum cannot be obtained. We provide a full description of the spectrum in different scenarios, and show that our model is consistent with the key observed properties of BHXRBs.

  19. An Evolving Compact Jet in the Black Hole X-Ray Binary Maxi J1836-194

    NASA Technical Reports Server (NTRS)

    Russell, D. M.; Russell, T. D.; Miller-Jones, J. C. A.; O'Brien, K.; Soria, R.; Sivakoff, G. R.; Slaven-Blair, T.; Lewis, F.; Markoff, S.; Homan, J.; Altanirano, D.; Curran, P. A.; Rupen, M. P.; Belloni, T. M.; Cadolle Bel, M.; Casella, P.; Corbel, S.; Dhawan, V.; Fender, R. P.; Gallo, E.; Gandhi, P.; Heinz, S.; Koerding, E. G.; Krimm, H. A.; Maitra, D.

    2013-01-01

    We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836-194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The optical-IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law, we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from approx 10(exp 11) to approx 4 × 10(exp 13) Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high-energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet. This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced, and hence their launching process.

  20. Apparatus and method for nanoflow liquid jet and serial femtosecond x-ray protein crystallography

    DOEpatents

    Bogan, Michael J.; Laksmono, Hartawan; Sierra, Raymond G.

    2016-03-01

    Techniques for nanoflow serial femtosecond x-ray protein crystallography include providing a sample fluid by mixing a plurality of a first target of interest with a carrier fluid and injecting the sample fluid into a vacuum chamber at a rate less than about 4 microliters per minute. In some embodiments, the carrier fluid has a viscosity greater than about 3 centipoise.

  1. Emission properties of ns and ps laser-induced soft x-ray sources using pulsed gas jets.

    PubMed

    Müller, Matthias; Kühl, Frank-Christian; Großmann, Peter; Vrba, Pavel; Mann, Klaus

    2013-05-20

    The influcence of the pulse duration on the emission characteristics of nearly debris-free laser-induced plasmas in the soft x-ray region (λ ≈ 1-5 nm) was investigated, using six different target gases from a pulsed jet. Compared to ns pulses of the same energy, a ps laser generates a smaller, more strongly ionized plasma, being about 10 times brighter than the ns laser plasma. Moreover, the spectra are considerably shifted towards shorter wavelengths. Electron temperatures and densities of the plasma are obtained by comparing the spectra with model calculations using a magneto-hydrodynamic code.

  2. Mapping the Ionization State of Laser-Irradiated Ar Gas Jets With Multi-Wavelength Monochromatic X-Ray Imaging

    SciTech Connect

    Kugland, N L; Doppner, T; Kemp, A; Schaeffer, D; Glenzer, S H; Niemann, C

    2010-04-08

    Two-dimensional monochromatic images of fast-electron stimulated Ar K{alpha} and He-{alpha} x-ray self-emission have recorded a time-integrated map of the extent of Ar{sup {approx}6+} and Ar{sup 16+} ions, respectively, within a high density (10{sup 20} cm{sup -3} atomic density) Ar plasma. This plasma was produced by irradiating a 2 mm wide clustering Ar gas jet with an ultra-high intensity (10{sup 19} W/cm{sup 2}, 200 fs) Ti:Sapphire laser operating at 800 nm. Spherically bent quartz crystals in the 200 (for K{alpha}) and 201 (for He-{alpha}) planes were used as near-normal incidence reflective x-ray optics. We see that a large (830 {micro}m long) region of plasma emits K{alpha} primarily along the laser axis, while the He-{alpha} emission is confined to smaller hot spot (230 {micro}m long) region that likely corresponds to the focal volume of the f/8 laser beam. X-ray spectra from a Bragg spectrometer operating in the von Hamos geometry, which images in one dimension, indicate that the centroids of the K{alpha} and He-{alpha} emission regions are separated by approximately 330 {micro}m along the laser axis.

  3. AN X-RAY VIEW OF THE JET CYCLE IN THE RADIO-LOUD AGN 3C120

    SciTech Connect

    Lohfink, Anne M.; Reynolds, Christopher S.; Mushotzky, Richard F.; Tombesi, Francesco; Jorstad, Svetlana G.; Marscher, Alan P.; Miller, Eric D.; Nowak, Michael A.; Aller, Hugh; Aller, Margo F.; Miller, Jon M.; Brenneman, Laura W.; Fabian, Andrew C.

    2013-08-01

    We present a study of the central engine in the broad-line radio galaxy 3C120 using a multi-epoch analysis of a deep XMM-Newton observation and two deep Suzaku pointings (in 2012). In order to place our spectral data into the context of the disk-disruption/jet-ejection cycles displayed by this object, we monitor the source in the UV/X-ray bands, and in the radio band. We find three statistically acceptable spectral models: a disk-reflection model, a jet model, and a jet+disk model. Despite being good descriptions of the data, the disk-reflection model violates the radio constraints on the inclination, and the jet model has a fine-tuning problem, requiring a jet contribution exceeding that expected. Thus, we argue for a composite jet+disk model. Within the context of this model, we verify the basic predictions of the jet-cycle paradigm, finding a truncated/refilling disk during the Suzaku observations and a complete disk extending down to the innermost stable circular orbit during the XMM-Newton observation. The idea of a refilling disk is further supported by the detection of the ejection of a new jet knot approximately one month after the Suzaku pointings. We also discover a step-like event in one of the Suzaku pointings in which the soft band lags the hard band. We suggest that we are witnessing the propagation of a disturbance from the disk into the jet on a timescale set by the magnetic field.

  4. The subarcsecond mid-infrared view of local active galactic nuclei - II. The mid-infrared-X-ray correlation

    NASA Astrophysics Data System (ADS)

    Asmus, D.; Gandhi, P.; Hönig, S. F.; Smette, A.; Duschl, W. J.

    2015-11-01

    We present an updated mid-infrared (MIR) versus X-ray correlation for the local active galactic nuclei (AGN) population based on the high angular resolution 12 and 18μm continuum fluxes from the AGN subarcsecond MIR atlas and 2-10 keV and 14-195 keV data collected from the literature. We isolate a sample of 152 objects with reliable AGN nature and multi-epoch X-ray data and minimal MIR contribution from star formation. Although the sample is not homogeneous or complete, we show that our results are unlikely to be affected by significant biases. The MIR-X-ray correlation is nearly linear and within a factor of 2 independent of the AGN type and the wavebands used. The observed scatter is <0.4 dex. A possible flattening of the correlation slope at the highest luminosities probed (˜1045 erg s-1) towards low MIR luminosities for a given X-ray luminosity is indicated but not significant. Unobscured objects have, on average, an MIR-X-ray ratio that is only ≤0.15 dex higher than that of obscured objects. Objects with intermediate X-ray column densities (22 < log NH < 23) actually show the highest MIR-X-ray ratio on average. Radio-loud objects show a higher mean MIR-X-ray ratio at low luminosities while the ratio is lower than average at high luminosities. This may be explained by synchrotron emission from the jet contributing to the MIR at low luminosities and additional X-ray emission at high luminosities. True Seyfert 2 candidates do not show any deviation from the general behaviour suggesting that they possess a dusty obscurer as in other AGN. Double AGN also do not deviate. Finally, we show that the MIR-X-ray correlation can be used to investigate the AGN nature of uncertain objects. Specifically, we give equations that allow us to determine the intrinsic 2-10 keV luminosities and column densities for objects with complex X-ray properties to within 0.34 dex. These techniques are applied to the uncertain objects of the remaining AGN MIR atlas, demonstrating the

  5. Analysis of the Response of CVD Diamond Detectors for UV and sX-Ray Plasma Diagnostics Installed at JET

    NASA Astrophysics Data System (ADS)

    Caiffi, B.; Coffey, I.; Pillon, M.; Osipenko, M.; Prestopino, G.; Ripani, M.; Taiuti, M.; Verona, C.; Verona-Rinati, G.

    Diamond detectors are very promising candidates for plasma diagnostics in a harsh environment. In fact, they have several proprieties which make them suitable for magnetic fusion devices: radiation hardness, high thermal conductivity, high resistivity, high carrier mobility and a large bandgap (5.5 eV). The latter makes them insensitive to visible radiation and allows low noise measurements without any cooling. In 2008 two CVD (Chemical Vapour Deposition) single crystal diamond (SCD) detectors were installed at the JET tokamak as extreme UV and soft X-Ray diagnostics [1]. In this work the neutron background in these detectors was measured shielding the UV and soft X-Ray radiation by closing a local vacuum valve. The UV detector was found to be insensitive to the neutron flux, while the soft X Ray detector signal exhibited spikes during the highest neutron rate pulse (neutron rate 1016n/s, which corresponds to a flux of φn ˜105n/cm2s in the detector location). These spikes were found to be due to the (n,p) reaction within the plastic filter in front of the soft X-Ray detector. The UV SCD was also used to perform time of flight (ToF) measurements in laser ablation experiments. ToFs were found to be an order of magnitude higher than expected if only the drift velocity is considered. This discrepancy could be due to a delay between the arrival time of the impurities in the plasma and their emission in an energy range which SCD is sensitive to (Eph >5.5 eV). The delay is found to be comparable with the expected ionization times for edge plasma conditions.

  6. Optical and X-Ray Observations of GRB 060526: A Complex Afterglow Consistent with an Achromatic Jet Break

    NASA Technical Reports Server (NTRS)

    Dai, X.; Halpern, J. P.; Morgan, N. D.; Armstrong, E.; Mirabal, N.; Haislip. J. B.; Reichart, D. E.; Stanek, K. Z.

    2007-01-01

    We obtained 98 R-band and 18 B, r', i' images of the optical afterglow of GRB 060526 (z = 3.21) with the MDM 1.3 m, 2.4 m, and the PROMPT telescopes at CTIO over the five nights following the burst trigger. Combining these data with other optical observations reported in GCN and the Swift XRT observations, we compare the optical and X-ray afterglow light curves of GRB 060526. Both the optical and X-ray afterglow light curves show rich features, such as flares and breaks. The densely sampled optical observations provide very good coverage at T > 10(exp 4) s. We observed a break at 2.4 x 10(exp 5) sin the optical afterglow light curve. Compared with the X-ray afterglow light curve, the break is consistent with an achromatic break supporting the beaming models of GRBs. However, the prebreak and postbreak temporal decay slopes are difficult to explain in simple afterglow models. We estimated a jet angle of theta(sub j) approx. 7deg and a prompt emission size of R(sub prompt) approx. 2 x 10(exp 14) cm. In addition, we detected several optical flares with amplitudes of (Delta)m approx. 0.2,0.6, and 0.2 mag. The X-ray afterglows detected by Swift have shown complicated decay patterns. Recently, many well-sampled optical afterglows also show decays with flares and multiple breaks. GRB 060526 provides an additional case of such a complex, well-observed optical afterglow. The accumulated well-sampled afterglows indicate that most of the optical afterglows are complex.

  7. DISCOVERY OF A KILOPARSEC-SCALE X-RAY/RADIO JET IN THE z = 4.72 QUASAR GB 1428+4217

    SciTech Connect

    Cheung, C. C.; Stawarz, L.; Siemiginowska, A.; Harris, D. E.; Schwartz, D. A.; Gobeille, D.; Wardle, J. F. C.

    2012-09-01

    We report the discovery of a one-sided 3.''6 (24 kpc, projected) long jet in the high-redshift, z = 4.72, quasar GB 1428+4217 in new Chandra X-ray and Very Large Array (VLA) radio observations. This is the highest redshift kiloparsec-scale X-ray/radio jet known. Analysis of archival very long baseline interferometry 2.3 and 8.6 GHz data reveal a faint one-sided jet extending out to {approx}200 pc and aligned to within {approx}30 Degree-Sign of the Chandra/VLA emission. The 3.''6 distant knot is not detected in an archival Hubble Space Telescope image, and its broadband spectral energy distribution is consistent with an origin from inverse Compton scattering of cosmic microwave background photons for the X-rays. Assuming also equipartition between the radiating particles and magnetic field, the implied jet Lorentz factor is Almost-Equal-To 5. This is similar to the other two known z {approx} 4 kpc scale X-ray jet cases and smaller than typically inferred in lower-redshift cases. Although there are still but a few such very high redshift quasar X-ray jets known, for an inverse Compton origin, the present data suggest that they are less relativistic on large scales than their lower-redshift counterparts.

  8. The ROSAT-ESO flux limited X-ray galaxy cluster survey (REFLEX II). I. Newly identified X-ray luminous clusters at z ≥ 0.2

    NASA Astrophysics Data System (ADS)

    Chon, G.; Böhringer, H.

    2012-02-01

    We report 19 intermediate redshift clusters newly detected in the ROSAT All-Sky survey that are spectroscopically confirmed. They form a part of 911 objects in the REFLEX II cluster catalogue with a limiting flux of 1.8 × 10-12 erg/s/cm2 in the 0.1-2.4 keV ROSAT band at redshift z ≥ 0.2. In addition we report three clusters from the REFLEX III supplementary catalogue, which contains objects below the REFLEX II flux limit but satisfies the redshift constraint above. These clusters are spectroscopically followed-up by our ESO NTT-EFOSC2 campaigns for the redshift measurement. We describe our observing and data reduction methods. We show how X-ray properties such as spectral hardness ratio and source extent can be used as important diagnostics in selecting galaxy cluster candidates. Physical properties of the clusters are subsequently calculated from the X-ray observations. This sample contains the high mass and intermediate-redshift galaxy clusters for astrophysical and cosmological applications. Based on the data obtained at the European Southern Observatory, La Silla, Chile.

  9. Achieving Vibration Stability of the NSLS-II Hard X-ray Nanoprobe Beamline

    SciTech Connect

    Simos, N.; Chu, Y. N.; Broadbent, A.; Nazaretski, E.; Margulies, L.; Dyling, O.; Shen, Q.; Fallier, M.

    2010-08-30

    The Hard X-ray Nanoprobe (HXN) Beamline of National Synchrotron Light Source II (NSLS-lI) requires high levels of stability in order to achieve the desired instrument resolution. To ensure that the design of the endstation helps meet the stringent criteria and that natural and cultural vibration is mitigated both passively and actively, a comprehensive study complimentary to the design process has been undertaken. Vibration sources that have the potential to disrupt sensitive experiments such as wind, traffic and NSLS II operating systems have been studied using state of the art simulations and an array of field data. Further, final stage vibration isolation principles have been explored in order to be utilized in supporting endstation instruments. This paper presents results of the various study aspects and their influence on the HXN design optimization.

  10. Small-angle x-ray scattering studies of the manganese stabilizing subunit in photosystem II.

    SciTech Connect

    Svensson, B.; Tiede, D. M.; Barry, B. A.; Univ. of Minnesota

    2002-08-29

    Small-angle X-ray scattering studies (SAXS) were used to determine the size, shape, and oligomeric composition of the manganese stabilizing protein (MSP) of photosystem II. This extrinsic protein subunit plays an important role in photosynthetic oxygen evolution. As its name implies, MSP stabilizes the tetranuclear Mn cluster of the water oxidation complex. Removal of MSP lowers activity and decreases the stability of active-site manganese. Reconstitution of MSP reverses these effects. In this study, MSP was extracted from spinach PSII membranes using CaCl{sub 2} or urea. Through the use of MALDI-TOF mass spectrometry, the molecular weight of MSP was determined to be 26.53 kDa. X-ray scattering results show that both samples display a monodisperse scattering pattern; this pattern is consistent with a homogeneous protein solution. The CaCl{sub 2} extracted and urea extracted MSP samples have radii of gyration of 25.9 {+-} 0.4 and 27.0 {+-} 0.01 {angstrom}, respectively. MSP is shown to be monomeric in solution. This was determined using a cytochrome c standard and the scattering intensity, extrapolated to zero scattering angle, which is proportional to the molecular weight. This SAXS study suggests that, in solution, MSP is a monomeric, elongated prolate ellipsoid with dimensions, 112 x 23 x 23 {angstrom}{sup 3} and an axial ratio of 4.8.

  11. Observations of a soft X-ray rising loop associated with a type II burst and a coronal mass ejection in the 03 November 2003 X-ray flare

    NASA Astrophysics Data System (ADS)

    Dauphin, C.; Vilmer, N.; Krucker, S.

    2006-08-01

    Context: .We report observations of a type II burst - the signature of a shock wave - starting at the unusual high frequency of 650 MHz during the 03 November 2003 flare. This flare is associated with the propagation of a soft X-ray coronal loop and with a coronal mass ejection (CME). Aims: .We study in this paper the origin of the shock wave in the low corona and present a kinematics analysis of the soft X-ray coronal loop and of the CME observed a few tens of minutes later. Methods: .We study in this paper the spatial and temporal relation between the soft X-ray rising loop observed by the GOES soft X-ray Imager (GOES/SXI), the type II sources observed by the Nançay Radio Heliograph (NRH) and the CME observed by LASCO (Large Angle and Spectroscopic Coronograph). Results: .This analysis shows that the type II burst observed during this flare is driven by the X-ray rising loop. Furthermore, the kinematics analysis of the X-ray coronal loop and CME shows that the two structures are related. Conclusions: .The direct comparison of the type II sources with the GOES/SXI observations clearly shows that the type II burst is ignited by the shock wave created ahead of the rising X-ray loop. Finally, we propose to interpret these different observations in the framework of an ascending magnetic structure with a reconnecting process operating in the tail of this ascending structure.

  12. Formation and propagation of laser-driven plasma jets in an ambient medium studied with X-ray radiography and optical diagnostics

    SciTech Connect

    Dizière, A.; Pelka, A.; Ravasio, A.; Yurchak, R.; Loupias, B.; Falize, E.; Kuramitsu, Y.; Sakawa, Y.; Morita, T.; Pikuz, S.; Koenig, M.

    2015-01-15

    In this paper, we present experimental results obtained on the LULI2000 laser facility regarding structure and dynamics of astrophysical jets propagating in interstellar medium. The jets, generated by using a cone-shaped target, propagate in a nitrogen gas that mimics the interstellar medium. X-ray radiography as well as optical diagnostics were used to probe both high and low density regions. In this paper, we show how collimation of the jets evolves with the gas density.

  13. Broad-band monitoring tracing the evolution of the jet and disc in the black hole candidate X-ray binary MAXI J1659-152

    NASA Astrophysics Data System (ADS)

    van der Horst, A. J.; Curran, P. A.; Miller-Jones, J. C. A.; Linford, J. D.; Gorosabel, J.; Russell, D. M.; de Ugarte Postigo, A.; Lundgren, A. A.; Taylor, G. B.; Maitra, D.; Guziy, S.; Belloni, T. M.; Kouveliotou, C.; Jonker, P. G.; Kamble, A.; Paragi, Z.; Homan, J.; Kuulkers, E.; Granot, J.; Altamirano, D.; Buxton, M. M.; Castro-Tirado, A.; Fender, R. P.; Garrett, M. A.; Gehrels, N.; Hartmann, D. H.; Kennea, J. A.; Krimm, H. A.; Mangano, V.; Ramirez-Ruiz, E.; Romano, P.; Wijers, R. A. M. J.; Wijnands, R.; Yang, Y. J.

    2013-12-01

    MAXI J1659-152 was discovered on 2010 September 25 as a new X-ray transient, initially identified as a gamma-ray burst, but was later shown to be a new X-ray binary with a black hole as the most likely compact object. Dips in the X-ray light curves have revealed that MAXI J1659-152 is the shortest period black hole candidate identified to date. Here we present the results of a large observing campaign at radio, submillimetre, near-infrared (nIR), optical and ultraviolet (UV) wavelengths. We have combined this very rich data set with the available X-ray observations to compile a broad-band picture of the evolution of this outburst. We have performed broad-band spectral modelling, demonstrating the presence of a spectral break at radio frequencies and a relationship between the radio spectrum and X-ray states. Also, we have determined physical parameters of the accretion disc and put them into context with respect to the other parameters of the binary system. Finally, we have investigated the radio-X-ray and nIR/optical/UV-X-ray correlations up to ˜3 yr after the outburst onset to examine the link between the jet and the accretion disc, and found that there is no significant jet contribution to the nIR emission when the source is in the soft or intermediate X-ray spectral state, consistent with our detection of the jet break at radio frequencies during these states.

  14. Jets, hotspots and lobes: what X-ray observations tell us about extra-galactic radio sources.

    PubMed

    Hardcastle, Martin J

    2005-12-15

    The brightest and most numerous discrete radio sources in the sky, radio galaxies and quasars, are powered by twin jets of plasma which emerge at relativistic speeds from very small regions at the centre of large elliptical galaxies, powered by mass infall on to supermassive black holes. The jets can carry material out to very large distances (millions of light years) where it forms balloon-like lobes. Until recently it has been impossible to make definite statements about the energy or the nature of the matter supplied by the jets, or the dynamics of the lobes as they expand into the external medium. This has meant that crucial questions about the generation of radio sources and their effect on their environment have gone unanswered. The situation has been revolutionized by the launch at the start of this decade of a new generation of X-ray observatories, Chandra and XMM-Newton. In this article, I explain why observations with these instruments have made such a difference, what we have learned as a result and why the community remains divided on some important features of the interpretation of the data.

  15. FERMI RULES OUT THE INVERSE COMPTON/CMB MODEL FOR THE LARGE-SCALE JET X-RAY EMISSION OF 3C 273

    SciTech Connect

    Meyer, Eileen T.; Georganopoulos, Markos

    2014-01-10

    The X-ray emission mechanism in large-scale jets of powerful radio quasars has been a source of debate in recent years, with two competing interpretations: either the X-rays are of synchrotron origin, arising from a different electron energy distribution than that producing the radio to optical synchrotron component, or they are due to inverse Compton scattering of cosmic microwave background photons (IC/CMB) by relativistic electrons in a powerful relativistic jet with bulk Lorentz factor Γ ∼ 10-20. These two models imply radically different conditions in the large-scale jet in terms of jet speed, kinetic power, and maximum energy of the particle acceleration mechanism, with important implications for the impact of the jet on the large-scale environment. A large part of the X-ray origin debate has centered on the well-studied source 3C 273. Here we present new observations from Fermi which put an upper limit on the gamma-ray flux from the large-scale jet of 3C 273 that violates at a confidence greater that 99.9% the flux expected from the IC/CMB X-ray model found by extrapolation of the UV to X-ray spectrum of knot A, thus ruling out the IC/CMB interpretation entirely for this source when combined with previous work. Further, this upper limit from Fermi puts a limit on the Doppler beaming factor of at least δ < 9, assuming equipartition fields, and possibly as low as δ < 5, assuming no major deceleration of the jet from knots A through D1.

  16. Characterising the local void with the X-ray cluster survey REFLEX II

    NASA Astrophysics Data System (ADS)

    Collins, Chris A.; Böhringer, Hans; Bristow, Martyn; Chon, Gayoung

    2016-10-01

    Claims of a significant underdensity or void in the density distribution on scales out to ~= 300 Mpc have recently been made using samples of galaxies. We present the results of an alternative test of the matter distribution on these scales using clusters of galaxies, which provide an independent and powerful probe of large-scale structure. We study the density distribution of X-ray clusters from the ROSAT-based REFLEX II catalogue, which covers a contiguous area of 4.24 steradians in the southern hempsphere (34% of the entire sky). Using the normalised comoving number density of clusters we find evidence for an underdensity (30-40%), out to z~ 0.04, equivalent to ~=170 Mpc and with a significance of 3.4σ. On scales between 300 Mpc and 1 Gpc the distribution of REFLEX II clusters is consistent with being uniform. We also confirm recent results that the underdensity has a large contribution from the direction of the South Galactic Cap region, but is not significant in the direction of the Northern Galactic Cap as viewed from the southern sky. Both the limited size of the detected underdensity and its lack of isotropy, argue against the idea that the Type Ia supernovae data can be explained without the need for dark energy.

  17. VLA observations of a complete sample of extragalactic X-ray sources. II

    NASA Technical Reports Server (NTRS)

    Schild, R.; Zamorani, G.; Gioia, I. M.; Feigelson, E. D.; Maccacaro, T.

    1983-01-01

    A complete sample of 35 X-ray selected sources found with the Einstein Observatory has been observed with the Very Large Array at 6 cm to investigate the relationship between radio and X-ray emission in extragalactic objects. Detections include three active galactic nuclei (AGNs), two clusters or groups of galaxies, two individual galaxies, and two BL Lac objects. The frequency of radio emission in X-ray selected AGNs is compared with that of optically selected quasars using the integral radio-optical luminosity function. The result suggests that the probability for X-ray selected quasars to be radio sources is higher than for those optically selected. No obvious correlation is found in the sample between the richness of X-ray luminosity of the cluster and the presence of a galaxy with radio luminosity at 5 GHz larger than 10 to the 30th ergs/s/Hz.

  18. Segal crystallinity index revisited by the simulation of X-ray diffraction patterns of cotton cellulose IB and cellulose II

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Segal method estimates the amorphous fraction of cellulose IB materials simply based on intensity at 18o 20 in an X-ray diffraction pattern and was extended to cellulose II using 16o 2O intensity. To address the dependency of Segal amorphous intensity on crystal size, cellulose polymorph, and th...

  19. SWIFT X-RAY OBSERVATIONS OF CLASSICAL NOVAE. II. THE SUPER SOFT SOURCE SAMPLE

    SciTech Connect

    Schwarz, Greg J.; Ness, Jan-Uwe; Osborne, J. P.; Page, K. L.; Evans, P. A.; Beardmore, A. P.; Walter, Frederick M.; Andrew Helton, L.; Woodward, Charles E.; Bode, Mike; Starrfield, Sumner; Drake, Jeremy J.

    2011-12-01

    The Swift gamma-ray burst satellite is an excellent facility for studying novae. Its rapid response time and sensitive X-ray detector provides an unparalleled opportunity to investigate the previously poorly sampled evolution of novae in the X-ray regime. This paper presents Swift observations of 52 Galactic/Magellanic Cloud novae. We included the X-Ray Telescope (0.3-10 keV) instrument count rates and the UltraViolet and Optical Telescope (1700-8000 A) filter photometry. Also included in the analysis are the publicly available pointed observations of 10 additional novae the X-ray archives. This is the largest X-ray sample of Galactic/Magellanic Cloud novae yet assembled and consists of 26 novae with Super Soft X-ray emission, 19 from Swift observations. The data set shows that the faster novae have an early hard X-ray phase that is usually missing in slower novae. The Super Soft X-ray phase occurs earlier and does not last as long in fast novae compared to slower novae. All the Swift novae with sufficient observations show that novae are highly variable with rapid variability and different periodicities. In the majority of cases, nuclear burning ceases less than three years after the outburst begins. Previous relationships, such as the nuclear burning duration versus t{sub 2} or the expansion velocity of the eject and nuclear burning duration versus the orbital period, are shown to be poorly correlated with the full sample indicating that additional factors beyond the white dwarf mass and binary separation play important roles in the evolution of a nova outburst. Finally, we confirm two optical phenomena that are correlated with strong, soft X-ray emission which can be used to further increase the efficiency of X-ray campaigns.

  20. Positions of galactic X-ray sources - At longitudes /l-II/ of 55-320 deg

    NASA Technical Reports Server (NTRS)

    Dower, R. G.; Bradt, H. V.; Doxsey, R. E.; Jernigan, J. G.; Kulik, J.; Apparao, K. M. V.

    1978-01-01

    Rotating modulation collimeter detectors on the SAS-3 X-ray observatory were used to supply precise (20-40 sec) positional data on 10 galactic X-ray sources in the l super II region between 55 and 320 deg. It is noted that the position for 2S0114+650 has led to the discovery of an optical counterpart. Attention is given to the temperature dependence of the experiments, and it is found that position measurements made at low temperatures are consistent with those obtained at normal (0 C) temperatures. Positions, error radii, and intensities (2-11 keV) are listed for each of the ten sources.

  1. Discovery of the correlation between peak episodic jet power and X-ray peak luminosity of the soft state in black hole transients

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Yu, W.

    2015-08-01

    Episodic jets are usually observed in the intermediate state of black hole transients during their X-ray outbursts. Here we report the discovery of a strong positive correlation between the peak radio power of the episodic jet Pjet and the corresponding peak X-ray luminosity Lx of the soft state (in Eddington units) in a complete sample of the outbursts of black hole transients observed during the RXTE era of which data are available, which follows the relation log Pjet = (2.2 ± 0.3) + (1.6 ± 0.2) × log Lx. The transient ultraluminous X-ray source in M31 and HLX-1 in EXO 243-49 fall on the relation if they contain stellar-mass black hole and either stellar-mass black hole or intermediate-mass black hole, respectively. Besides, a significant correlation between the peak power of the episodic jet and the rate of increase of the X-ray luminosity dLx/dt during the rising phase of those outbursts is also found, following log Pjet = (2.0 ± 0.4) + (0.7 ± 0.2) × log dLx/dt. In GX 339-4 and H 1743-322 in which data for two outbursts are available, measurements of the peak radio power of the episodic jet and the X-ray peak luminosity (and its rate of change) shows similar positive correlations between outbursts, which demonstrate the dominant role of accretion over black hole spin in generating episodic jet power. On the other hand, no significant difference is seen among the systems with different measured black hole spin in current sample. This implies that the power of the episodic jet is strongly affected by non-stationary accretion instead of black hole spin characterized primarily by the rate of change of the mass accretion rate.

  2. Continued Evolution of the X-ray Jets and Lobes of the R Aquarii Symbiotic Star System

    NASA Astrophysics Data System (ADS)

    Kellogg, Edwin M.; Nichols, J.; Anderson, C.

    2009-01-01

    New jets have emerged in 2005.7 from the central binary in R Aquarii since our previously reported Chandra and VLA observations in 2000 and 2004. Although the new activity has been reported at previous AAS meetings, we present here the results of detailed analysis of the new activity, including an exhaustive search for short term variability. In spite of the detection of a 1734 s period at a 95% confidence level in an observation of R Aqr taken in 2004.0, we were unable to detect any variability in this more recent 2005.7 observation. The methods used to search for variability are described, as well as analysis of the x-ray spectra of the central compact source, the non-thermal jets and the thermal outer lobes. The longer exposure 2005.7 observation is considerably more sensitive than the previous two, and reveals more detail and new spectral features than previously. The bright, prominent NE lobe continues to move outward, but has changed direction and speed. The main SW lobe, which had faded between 2000 and 2004, has not faded further, but has changed shape. The 2005.7 observation reveals a still fainter lobe between the main SW lobe and the central source, with enough counts to give a rough temperature estimation.

  3. CHEMICAL PROCESSES IN PROTOPLANETARY DISKS. II. ON THE IMPORTANCE OF PHOTOCHEMISTRY AND X-RAY IONIZATION

    SciTech Connect

    Walsh, Catherine; Millar, T. J.; Nomura, Hideko; Aikawa, Yuri

    2012-03-10

    We investigate the impact of photochemistry and X-ray ionization on the molecular composition of, and ionization fraction in, a protoplanetary disk surrounding a typical T Tauri star. We use a sophisticated physical model, which includes a robust treatment of the radiative transfer of UV and X-ray radiation, and calculate the time-dependent chemical structure using a comprehensive chemical network. In previous work, we approximated the photochemistry and X-ray ionization; here, we recalculate the photoreaction rates using the explicit UV wavelength spectrum and wavelength-dependent reaction cross sections. We recalculate the X-ray ionization rate using our explicit elemental composition and X-ray energy spectrum. We find that photochemistry has a larger influence on the molecular composition than X-ray ionization. Observable molecules sensitive to the photorates include OH, HCO{sup +}, N{sub 2}H{sup +}, H{sub 2}O, CO{sub 2}, and CH{sub 3}OH. The only molecule significantly affected by the X-ray ionization is N{sub 2}H{sup +}, indicating that it is safe to adopt existing approximations of the X-ray ionization rate in typical T Tauri star-disk systems. The recalculation of the photorates increases the abundances of neutral molecules in the outer disk, highlighting the importance of taking into account the shape of the UV spectrum in protoplanetary disks. A recalculation of the photoreaction rates also affects the gas-phase chemistry due to the adjustment of the H/H{sub 2} and C{sup +}/C ratios. The disk ionization fraction is not significantly affected by the methods adopted to calculate the photochemistry and X-ray ionization. We determine that there is a probable 'dead zone' where accretion is suppressed, present in a layer, Z/R {approx}< 0.1-0.2, in the disk midplane, within R Almost-Equal-To 200 AU.

  4. Symbiotic Stars in X-rays. II. Faint Sources Detected with XMM-Newton and Chandra

    NASA Technical Reports Server (NTRS)

    Nunez, N. E.; Luna, G. J. M.; Pillitteri, I.; Mukai, K.

    2014-01-01

    We report the detection from four symbiotic stars that were not known to be X-ray sources. These four object show a ß-type X-ray spectrum, that is, their spectra can be modeled with an absorbed optically thin thermal emission with temperatures of a few million degrees. Photometric series obtained with the Optical Monitor on board XMM-Newton from V2416 Sgr and NSV 25735 support the proposed scenario where the X-ray emission is produced in a shock-heated region inside the symbiotic nebulae.

  5. Artifacts in energy dispersive x-ray spectrometry in the scanning electron microscope (II).

    PubMed

    Fiori, C E; Newbury, D E

    1980-01-01

    The quality of x-ray spectra obtained with an energy dispersive x-ray spectrometer on an electron beam instrument can be severely compromised by the presence of electromagnetic interference. Sources of electromagnetic interference include ground currents and signals generated by time-varying currents in instrument components such as scan coils. Spectrometer resolution can be degraded by the accumulation of ice and vaccum oil on critical components of the device. Operation at high electron energy can cause artifacts in spectra due to direct entry of electrons and spurious x-rays into the detector. Processing high energy photons (above 40 keV) can lead to detector saturation effects which degrade resolution and affect dead time correction. Transmission of high energy x-rays through the detector accompanied by Compton scattering can lead to a distortion of the low energy portion of the spectrum.

  6. Chandra X-ray Observations of Young Clusters. Volume II; Orion Flanking Fields Data

    NASA Technical Reports Server (NTRS)

    Ramirez, Solange V.; Rebull, Luisa; Stauffer, John; Strom, Stephen; Hillenbrand, Lynne; Hearty, Thomas; Kopan, Eugene L.; Pravdo, Steven; Makidon, Russell; Jones, Burton

    2004-01-01

    We present results of Chandra observations of two flanking fields (FFs) in Orion, outside the Orion Nebula Cluster (ONC). The observations were taken with the ACIS-I camera with an exposure time of about 48 ks each field. We present a catalog of 417 sources, which includes X-ray luminosity, optical and infrared photometry, and X-ray variability information. We have found 91 variable sources, 33 of which have a flarelike light curve and 11 of which have a pattern of a steady increase or decrease over a 10 hr period. The optical and infrared photometry for the stars identified as X-ray sources are consistent with most of these objects being pre-main-sequence stars with ages younger than 10 Myr. We present evidence for an age difference among the X-ray-selected samples of NGC 2264, Orion FFs, and ONC, with NGC 2264 being the oldest and ONC being the youngest.

  7. Artifacts in energy dispersive x-ray spectrometry in the scanning electron microscope (II).

    PubMed

    Fiori, C E; Newbury, D E

    1980-01-01

    The quality of x-ray spectra obtained with an energy dispersive x-ray spectrometer on an electron beam instrument can be severely compromised by the presence of electromagnetic interference. Sources of electromagnetic interference include ground currents and signals generated by time-varying currents in instrument components such as scan coils. Spectrometer resolution can be degraded by the accumulation of ice and vaccum oil on critical components of the device. Operation at high electron energy can cause artifacts in spectra due to direct entry of electrons and spurious x-rays into the detector. Processing high energy photons (above 40 keV) can lead to detector saturation effects which degrade resolution and affect dead time correction. Transmission of high energy x-rays through the detector accompanied by Compton scattering can lead to a distortion of the low energy portion of the spectrum. PMID:7423119

  8. THE NATURE OF THE UV/OPTICAL EMISSION OF THE ULTRALUMINOUS X-RAY SOURCE IN HOLMBERG II

    SciTech Connect

    Tao Lian; Feng Hua; Kaaret, Philip; Grise, Fabien

    2012-05-10

    We report on UV and X-ray spectroscopy and broadband optical observations of the ultraluminous X-ray source in Holmberg II. Fitting various stellar spectral models to the combined, non-simultaneous data set, we find that normal metallicity stellar spectra are ruled out by the data, while low-metallicity, Z = 0.1 Z{sub Sun }, late O-star spectra provide marginally acceptable fits, if we allow for the fact that X-ray ionization from the compact object may reduce or eliminate UV absorption/emission lines from the stellar wind. By contrast, an irradiated disk model fits both UV and optical data with {chi}{sup 2}/dof = 175.9/178, and matches the nebular extinction with a reddening of E(B - V) = 0.05{sup +0.05}{sub -0.04}. These results suggest that the UV/optical flux of Holmberg II X-1 may be dominated by X-ray irradiated disk emission.

  9. BAT AGN spectroscopic survey-II. X-ray emission and high-ionization optical emission lines

    NASA Astrophysics Data System (ADS)

    Berney, Simon; Koss, Michael; Trakhtenbrot, Benny; Ricci, Claudio; Lamperti, Isabella; Schawinski, Kevin; Baloković, Mislav; Crenshaw, D. Michael; Fischer, Travis; Gehrels, Neil; Harrison, Fiona; Hashimoto, Yasuhiro; Ichikawa, Kohei; Mushotzky, Richard; Oh, Kyuseok; Stern, Daniel; Treister, Ezequiel; Ueda, Yoshihiro; Veilleux, Sylvain; Winter, Lisa

    2015-12-01

    We investigate the relationship between X-ray and optical line emission in 340 nearby (z ≃ 0.04) AGN selected above 10 keV using Swift BAT. We find a weak correlation between the extinction corrected [O III] and hard X-ray luminosity (L_[O III]^{int} ∝ L_{14-195}) with a large scatter (RPear = 0.64, σ = 0.62 dex) and a similarly large scatter with the intrinsic 2-10 keV to [O III] luminosities (RPear = 0.63, σ = 0.63 dex). Correlations of the hard X-ray fluxes with the fluxes of high-ionization narrow lines ([O III], He II, [Ne III] and [Ne V]) are not significantly better than with the low-ionization lines (H α, [S II]). Factors like obscuration or physical slit size are not found to be a significant part of the large scatter. In contrast, the optical emission lines show much better correlations with each other (σ = 0.3 dex) than with the X-ray flux. The inherent large scatter questions the common usage of narrow emission lines as AGN bolometric luminosity indicators and suggests that other issues such as geometrical differences in the scattering of the ionized gas or long-term AGN variability are important.

  10. Novel bimetallic thiocyanate-bridged Cu(II)-Hg(II) compounds-synthesis, X-Ray studies and magnetic properties

    SciTech Connect

    Machura, B.; Switlicka, A.; Zwolinski, P.; Mrozinski, J.; Kalinska, B.; Kruszynski, R.

    2013-01-15

    Seven novel heterobimetallic Cu/Hg polymers based on thiocyanate bridges have been synthesised and characterised by means of IR, EPR, magnetic measurements and single crystal X-Ray. Three of them, [Cu(pzH){sub 4}Hg(SCN){sub 4}]{sub n} (1) [Cu(indH){sub 4}Hg(SCN){sub 4}]{sub n} (2) and [Cu(ampy){sub 2}Hg(SCN){sub 4}]{sub n} (3), have one-dimensional coordination structure. Two compounds [Cu(pzH){sub 2}Hg(SCN){sub 4}]{sub n} (4) and [Cu(abzimH)Hg(SCN){sub 4}]{sub n} (5) form two-dimensional nets, whereas the complexes [Cu(pyCN){sub 2}Hg(SCN){sub 4}]{sub n} (6) and [Cu(pyCH(OH)(OMe)){sub 2}Hg(SCN){sub 4}]{sub n} (7) are three-dimensional coordination polymers. The chains of 1 are connected by the intermolecular N-H Bullet Bullet Bullet N hydrogen bonds to the three dimensional net. In 2 the N-H Bullet Bullet Bullet S hydrogen bonds link the polymeric chains to the two dimensional layer extending along crystallographic (0 0 1) plane. The polymeric chains of compound 3 are joined by the intermolecular N-H Bullet Bullet Bullet N and N-H Bullet Bullet Bullet S hydrogen bonds to the three dimensional net. The polymeric layers of 4 are connected by the intermolecular N-H Bullet Bullet Bullet N hydrogen bonds to the three dimensional net. - Graphical abstract: Novel bimetallic thiocyanate-bridged Cu(II)-Hg(II) compound-synthesis,X-Ray studies and magnetic properties. Highlights: Black-Right-Pointing-Pointer Novel heterobimetallic Cu/Hg coordination polymers were synthesised. Black-Right-Pointing-Pointer The multidimensional structures have been proved by single X-ray analysIs. Black-Right-Pointing-Pointer A variation in the crystalline architectures was observed depending on auxiliary ligands. Black-Right-Pointing-Pointer Magnetic measurements indicate weak exchange interaction between Cu(II) in the crystal lattices below 10 K.

  11. Normal incidence X-ray telescope power spectra of X-ray emission from solar active regions. I - Observations. II - Theory

    NASA Technical Reports Server (NTRS)

    Gomez, Daniel O.; Martens, Petrus C. H.; Golub, Leon

    1993-01-01

    Fourier analysis is applied to very high resolution image of coronal active regions obtained by the Normal Incidence X-Ray Telescope is used to find a broad isotropic power-law spectrum of the spatial distribution of soft X-ray intensities. Magnetic structures of all sizes are present down to the resolution limit of the instrument. Power spectra for the X-ray intensities of a sample of topologically different active regions are found which fall off with increasing wavenumber as 1/k-cubed. A model is presented that relates the basic features of coronal magnetic fluctuations to the subphotospheric hydrodynamic turbulence that generates them. The model is used to find a theoretical power spectrum for the X-ray intensity which falls off with increasing wavenumber as 1/k-cubed. The implications of a turbulent regime in active regions are discussed.

  12. The Chandra planetary nebula survey (CHANPLANS). II. X-ray emission from compact planetary nebulae

    SciTech Connect

    Freeman, M.; Kastner, J. H.; Montez, R. Jr.; Balick, B.; Frew, D. J.; De Marco, O.; Parker, Q. A.; Jones, D.; Miszalski, B.; Sahai, R.; Blackman, E.; Frank, A.; Chu, Y.-H.; Guerrero, M. A.; Zijlstra, A.; Bujarrabal, V.; Corradi, R. L. M.; Nordhaus, J.; and others

    2014-10-20

    We present results from the most recent set of observations obtained as part of the Chandra X-ray observatory Planetary Nebula Survey (CHANPLANS), the first comprehensive X-ray survey of planetary nebulae (PNe) in the solar neighborhood (i.e., within ∼1.5 kpc of the Sun). The survey is designed to place constraints on the frequency of appearance and range of X-ray spectral characteristics of X-ray-emitting PN central stars and the evolutionary timescales of wind-shock-heated bubbles within PNe. CHANPLANS began with a combined Cycle 12 and archive Chandra survey of 35 PNe. CHANPLANS continued via a Chandra Cycle 14 Large Program which targeted all (24) remaining known compact (R {sub neb} ≲ 0.4 pc), young PNe that lie within ∼1.5 kpc. Results from these Cycle 14 observations include first-time X-ray detections of hot bubbles within NGC 1501, 3918, 6153, and 6369, and point sources in HbDs 1, NGC 6337, and Sp 1. The addition of the Cycle 14 results brings the overall CHANPLANS diffuse X-ray detection rate to ∼27% and the point source detection rate to ∼36%. It has become clearer that diffuse X-ray emission is associated with young (≲ 5 × 10{sup 3} yr), and likewise compact (R {sub neb} ≲ 0.15 pc), PNe with closed structures and high central electron densities (n{sub e} ≳ 1000 cm{sup –3}), and is rarely associated with PNe that show H{sub 2} emission and/or pronounced butterfly structures. Hb 5 is one such exception of a PN with a butterfly structure that hosts diffuse X-ray emission. Additionally, two of the five new diffuse X-ray detections (NGC 1501 and NGC 6369) host [WR]-type central stars, supporting the hypothesis that PNe with central stars of [WR]-type are likely to display diffuse X-ray emission.

  13. High K-alpha X-ray Conversion Efficiency From Extended Source Gas Jet Targets Irradiated by Ultra Short Laser Pulses

    SciTech Connect

    Kugland, N L; Constantin, C; Collette, A; Dewald, E; Froula, D; Glenzer, S H; Kritcher, A; Neumayer, P; Ross, J S; Niemann, C

    2007-11-01

    The absolute laser conversion efficiency to K{sub {alpha}}-like inner shell x-rays (integrated from K{sub {alpha}} to K{sub {beta}}) is observed to be an order of magnitude higher in argon gas jets than in solid targets due to enhanced emission from higher ionization stages following ultra short pulse laser irradiation. Excluding the higher ionization stages, the conversion efficiency to near-cold K{sub {alpha}} is the same in gas jets as in solid targets. These results demonstrate that gas jet targets are bright, high conversion efficiency, high repetition rate, debris-free multi-keV x-ray sources for spectrally resolved scattering and backlighting of rapidly evolving dense matter.

  14. Feedback from winds and supernovae in massive stellar clusters - II. X-ray emission

    NASA Astrophysics Data System (ADS)

    Rogers, H.; Pittard, J. M.

    2014-06-01

    The X-ray emission from a simulated massive stellar cluster is investigated. The emission is calculated from a 3D hydrodynamical model which incorporates the mechanical feedback from the stellar winds of three O stars embedded in a giant molecular cloud (GMC) clump containing 3240 M⊙ of molecular material within a 4 pc radius. A simple prescription for the evolution of the stars is used, with the first supernova (SN) explosion at t = 4.4 Myr. We find that the presence of the GMC clump causes short-lived attenuation effects on the X-ray emission of the cluster. However, once most of the material has been ablated away by the winds, the remaining dense clumps do not have a noticeable effect on the attenuation compared with the assumed interstellar medium (ISM) column. We determine the evolution of the cluster X-ray luminosity, LX, and spectra, and generate synthetic images. The intrinsic X-ray luminosity drops from nearly 1034 erg s-1 while the winds are `bottled up', to a near-constant value of 1.7 × 1032 erg s-1 between t = 1 and 4 Myr. LX reduces slightly during each star's red supergiant stage due to the depressurization of the hot gas. However, LX increases to ≈1034 erg s-1 during each star's Wolf-Rayet stage. The X-ray luminosity is enhanced by two to three orders of magnitude to ˜1037 erg s-1 for at least 4600 yr after each SN explosion, at which time the blast wave leaves the grid and the X-ray luminosity drops. The X-ray luminosity of our simulation is generally considerably fainter than predicted from spherically symmetric bubble models, due to the leakage of hot gas material through gaps in the outer shell. This process reduces the pressure within our simulation and thus the X-ray emission. However, the X-ray luminosities and temperatures which we obtain are comparable to similarly powerful massive young clusters.

  15. High Resolution Triple Axis X-Ray Diffraction Analysis of II-VI Semiconductor Crystals

    NASA Technical Reports Server (NTRS)

    Volz, H. M.; Matyi, R. J.

    1999-01-01

    The objective of this research program is to develop methods of structural analysis based on high resolution triple axis X-ray diffractometry (HRTXD) and to carry out detailed studies of defect distributions in crystals grown in both microgravity and ground-based environments. HRTXD represents a modification of the widely used double axis X-ray rocking curve method for the characterization of grown-in defects in nearly perfect crystals. In a double axis rocking curve experiment, the sample is illuminated by a monochromatic X-ray beam and the diffracted intensity is recorded by a fixed, wide-open detector. The intensity diffracted by the sample is then monitored as the sample is rotated through the Bragg reflection condition. The breadth of the peak, which is often reported as the full angular width at half the maximum intensity (FWHM), is used as an indicator of the amount of defects in the sample. This work has shown that high resolution triple axis X-ray diffraction is an effective tool for characterizing the defect structure in semiconductor crystals, particularly at high defect densities. Additionally, the technique is complimentary to X-ray topography for defect characterization in crystals.

  16. A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. II. X-Ray Variability

    NASA Astrophysics Data System (ADS)

    Nichols, J.; Huenemoerder, D. P.; Corcoran, M. F.; Waldron, W.; Nazé, Y.; Pollock, A. M. T.; Moffat, A. F. J.; Lauer, J.; Shenar, T.; Russell, C. M. P.; Richardson, N. D.; Pablo, H.; Evans, N. R.; Hamaguchi, K.; Gull, T.; Hamann, W.-R.; Oskinova, L.; Ignace, R.; Hoffman, Jennifer L.; Hole, K. T.; Lomax, J. R.

    2015-08-01

    We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral data set of the δ Ori Aa binary system. The four observations, obtained with Chandra ACIS HETGS, have a total exposure time of ≈ 479 ks and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range of 5-25 Å is confirmed, with a maximum amplitude of about ±15% within a single ≈ 125 ks observation. Periods of 4.76 and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in the flux level throughout the nine-day observational campaign. Using 40 ks contiguous spectra derived from the original observations, we investigate the variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S xv, Si xiii, and Ne ix. For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at ϕ = 0.0 when the secondary δ Ori Aa2 is at the inferior conjunction. Using 3D hydrodynamic modeling of the interacting winds, we relate the emission line width variability to the presence of a wind cavity created by a wind-wind collision, which is effectively void of embedded wind shocks and is carved out of the X-ray-producing primary wind, thus producing phase-locked X-ray variability. Based on data from the Chandra X-ray Observatory and the MOST satellite, a Canadian Space Agency mission, jointly operated by Dynacon Inc., the University of Toronto Institute of Aerospace Studies, and the University of British Columbia, with the assistance of the University of Vienna.

  17. Application of CO2 Snow Jet Cleaning in Conjunction with Laboratory Based Total Reflection X-Ray Fluorescence

    NASA Technical Reports Server (NTRS)

    Schmeling, M.; Burnett, D. S.; Allton, J. H.; Rodriquez, M.; Tripa, C. E.; Veryovkin, I. V.

    2013-01-01

    The Genesis mission was the first mission returning solar material to Earth since the Apollo program [1,2]. Unfortunately the return of the space craft on September 8, 2004 resulted in a crash landing, which shattered the samples into small fragments and exposed them to desert soil and other debris. Thus only small fragments of the original collectors are available, each having different degrees of surface contamination. Thorough surface cleaning is required to allow for subsequent analysis of solar wind material embedded within. An initial cleaning procedure was developed in coordination with Johnson Space Center which focused on removing larger sized particulates and a thin film organic contamination acquired during collection in space [3]. However, many of the samples have additional residues and more rigorous and/or innovative cleaning steps might be necessary. These cleaning steps must affect only the surface to avoid leaching and re-distribution of solar wind material from the bulk of the collectors. To aid in development and identification of the most appropriate cleaning procedures each sample has to be thoroughly inspected before and after each cleaning step. Laboratory based total reflection X-ray fluorescence (TXRF) spectrometry lends itself to this task as it is a non-destructive and surface sensitive analytical method permitting analysis of elements from aluminum onward present at and near the surface of a flat substrate [4]. The suitability of TXRF has been demonstrated for several Genesis solar wind samples before and after various cleaning methods including acid treatment, gas cluster ion beam, and CO2 snow jet [5 - 7]. The latter one is non-invasive and did show some promise on one sample [5]. To investigate the feasibility of CO2 snow jet cleaning further, several flown Genesis samples were selected to be characterized before and after CO2 snow application with sample 61052 being discussed below.

  18. Modeling Contamination Migration on the Chandra X-ray Observatory II

    NASA Technical Reports Server (NTRS)

    O'Dell, Steve; Swartz, Doug; Tice, Neil; Plucinsky, Paul; Grant, Catherine; Marshall, Herman; Vikhlinin, Alexey

    2013-01-01

    During its first 14 years of operation, the cold (about -60degC) optical blocking filter of the Advanced CCD Imaging Spectrometer (ACIS), aboard the Chandra X-ray Observatory, has accumulated a growing layer of molecular contamination that attenuates low-energy x rays. Over the past few years, the accumulation rate, spatial distribution, and composition may have changed, perhaps partially related to changes in the operating temperature of the ACIS housing. This evolution of the accumulation of the molecular contamination has motivated further analysis of contamination migration on the Chandra X-ray Observatory, particularly within and near the ACIS cavity. To this end, the current study employs a higher-fidelity geometric model of the ACIS cavity, detailed thermal modeling based upon monitored temperature data, and an accordingly refined model of the molecular transport.

  19. Modeling Contamination Migration on the Chandra X-ray Observatory - II

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Swartz, Douglas A.; Tice, Neil W.; Plucinsky, Paul P.; Grant, Catherine E.; Marshall, Herman L.; Vikhlinin, Alexey A.; Tennant, Allyn F.

    2013-01-01

    During its first 14 years of operation, the cold (about -60C) optical blocking filter of the Advanced CCD Imaging Spectrometer (ACIS), aboard the Chandra X-ray Observatory, has accumulated a growing layer of molecular contamination that attenuates low-energy x rays. Over the past few years, the accumulation rate, spatial distribution, and composition have changed. This evolution has motivated further analysis of contamination migration within and near the ACIS cavity. To this end, the current study employs a higher-fidelity geometric model of the ACIS cavity, detailed thermal modeling based upon temperature data, and a refined model of the molecular transport.

  20. Milliarcsec-scale radio emission of ultraluminous X-ray sources: steady jet emission from an intermediate-mass black hole?

    NASA Astrophysics Data System (ADS)

    Mezcua, M.; Farrell, S. A.; Gladstone, J. C.; Lobanov, A. P.

    2013-12-01

    The origin of the high X-ray luminosities of most ultraluminous X-ray sources (ULXs) still remains poorly understood. Most of the scenarios proposed to explain their nature assume that ULXs are powered by accretion on to a black hole (BH). In this case, the detection of compact radio emission and the location of the ULXs in the Fundamental Plane (X-ray versus radio-luminosity plane) can provide an estimate of the ULX BH mass and help address the question of their physical nature. We present the results of a high-resolution (very long baseline interferometry) radio observational campaign aimed at detecting and studying compact radio emission in four ULXs with known radio counterparts. We find that one of the targets (N4559-X4) was previously misclassified: its low X-ray luminosity indicates that the source is not a ULX. No milliarcsec-scale radio emission is detected for N4559-X4 nor for the ULXs N4490-X1 and N5194-X2, for which upper limits on the radio luminosities are estimated. These limits argue strongly against the presence of supermassive BHs in these three systems. For N4559-X4, the low X-ray luminosity and the ratio of the radio and X-ray luminosities suggest the presence of an X-ray binary. Compact radio emission is detected for the ULX N5457-X9 within its Chandra positional error, making N5457-X9 a potential intermediate-mass BH with steady jet emission.

  1. Wind, jet, hybrid corona and hard X-ray flares: Multiwavelength evolution of GRO J1655-40 during the 2005 outburst rise

    NASA Astrophysics Data System (ADS)

    Kalemci, E.; Begelman, M. C.; Maccarone, T. J.; Dincer, T.; Russell, T. D.; Bailyn, C.; Tomsick, J. A.

    2016-08-01

    We have investigated the complex multiwavelength evolution of GRO J1655-40 during the rise of its 2005 outburst. We detected two hard X-ray flares, the first one during the transition from the soft state to the ultra-soft state, and the second one in the ultra-soft state. The first X-ray flare coincided with an optically thin radio flare. We also observed a hint of increased radio emission during the second X-ray flare. To explain the hard flares without invoking a secondary emission component, we fit the entire dataset with the eqpair model. This single, hybrid Comptonization model sufficiently fits the data even during the hard X-ray flares if we allow reflection fractions greater than unity. In this case, the hard X-ray flares correspond to a Comptonizing corona dominated by non-thermal electrons. The fits also require absorption features in the soft and ultra-soft state which are likely due to a wind. In this work we show that the wind and the optically thin radio flare co-exist. Finally, we have also investigated the radio to optical spectral energy distribution, tracking the radio spectral evolution through the quenching of the compact jet and rise of the optically thin flare, and interpreted all data using state transition models.

  2. Wind, jet, hybrid corona and hard X-ray flares: multiwavelength evolution of GRO J1655-40 during the 2005 outburst rise

    NASA Astrophysics Data System (ADS)

    Kalemci, E.; Begelman, M. C.; Maccarone, T. J.; Dinçer, T.; Russell, T. D.; Bailyn, C.; Tomsick, J. A.

    2016-11-01

    We have investigated the complex multiwavelength evolution of GRO J1655-40 during the rise of its 2005 outburst. We detected two hard X-ray flares, the first one during the transition from the soft state to the ultra-soft state, and the second one in the ultra-soft state. The first X-ray flare coincided with an optically thin radio flare. We also observed a hint of increased radio emission during the second X-ray flare. To explain the hard flares without invoking a secondary emission component, we fit the entire data set with the eqpair model. This single, hybrid Comptonization model sufficiently fits the data even during the hard X-ray flares if we allow reflection fractions greater than unity. In this case, the hard X-ray flares correspond to a Comptonizing corona dominated by non-thermal electrons. The fits also require absorption features in the soft and ultra-soft state which are likely due to a wind. In this work we show that the wind and the optically thin radio flare co-exist. Finally, we have also investigated the radio to optical spectral energy distribution, tracking the radio spectral evolution through the quenching of the compact jet and rise of the optically thin flare, and interpreted all data using state transition models.

  3. The Galactic plane at faint X-ray fluxes - II. Stacked X-ray spectra of a sample of serendipitous XMM-Newton sources

    NASA Astrophysics Data System (ADS)

    Warwick, R. S.; Byckling, K.; Pérez-Ramírez, D.

    2014-03-01

    We have investigated the X-ray spectral properties of a sample of 138 X-ray sources detected serendipitously in XMM-Newton observations of the Galactic plane, at an intermediate to faint flux level. We divide our sample into five subgroups according to the spectral hardness of the sources, and stack (i.e. co-add) the individual source spectra within each subgroup. As expected these stacked spectra show a softening trend from the hardest to the softest subgroups, which is reflected in the inferred line-of-sight column density. The spectra of the three hardest subgroups are characterized by a hard continuum plus superimposed Fe-line emission in the 6-7 keV bandpass. The average equivalent width (EW) of the 6.7-keV He-like Fe Kα line is 170^{+35}_{-32} eV, whereas the 6.4-keV Fe K fluorescence line from neutral iron and the 6.9-keV H-like Fe Lyα line have EWs of 89^{+26}_{-25} and 81^{+30}_{-29} eV, respectively, i.e. roughly half that of the 6.7-keV line. The remaining subgroups exhibit soft thermal spectra. Virtually all of the spectrally soft X-ray sources can be associated with relatively nearby coronally active late-type stars, which are evident as bright near-infrared (NIR) objects within the X-ray error circles. On a similar basis only a minority of the spectrally hard X-ray sources have likely NIR identifications. The average continuum and Fe-line properties of the spectrally hard sources are consistent with those of magnetic cataclysmic variables but the direct identification of large numbers of such systems in Galactic X-ray surveys, probing intermediate to faint flux levels, remains challenging.

  4. A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, Delta Orionis Aa. II. X-Ray Variability

    NASA Technical Reports Server (NTRS)

    Nichols, J.; Huenemoerder, D. P.; Corcoran, M. F.; Waldron, W.; Naze, Y.; Pollock, A. M. T.; Moffat, A. F. J.; Lauer, J.; Shenar, T.; Russell, C. M. P.; Hamaguchi, K.; Gull, T.

    2015-01-01

    We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral data set of the delta Ori Aa binary system. The four observations, obtained with Chandra ACIS (Advanced CCD Imaging Spectrometer) HETGS (High Energy Transmission Grating), have a total exposure time approximately equal to 479 kiloseconds and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range of 5-25 angstroms is confirmed, with a maximum amplitude of about plus or minus15 percent within a single approximately equal to125 kiloseconds observation. Periods of 4.76 and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in the flux level throughout the nine-day observational campaign. Using 40 kiloseconds contiguous spectra derived from the original observations, we investigate the variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S (sub XV), Si (sub XIII), and Ne (sub IX). For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at phi = 0.0 when the secondary delta Ori Aa2 is at the inferior conjunction. Using 3D hydrodynamic modeling of the interacting winds, we relate the emission line width variability to the presence of a wind cavity created by a wind-wind collision, which is effectively void of embedded wind shocks and is carved out of the X-ray-producing primary wind, thus producing phase-locked X-ray variability.

  5. Advances in the detection of as in environmental samples using low energy X-ray fluorescence in a scanning transmission X-ray microscope: arsenic immobilization by an Fe(II)-oxidizing freshwater bacteria.

    PubMed

    Hitchcock, A P; Obst, M; Wang, J; Lu, Y S; Tyliszczak, T

    2012-03-01

    Speciation and quantitative mapping of elements, organic and inorganic compounds, and mineral phases in environmental samples at high spatial resolution is needed in many areas of geobiochemistry and environmental science. Scanning transmission X-ray microscopes (STXMs) provide a focused beam which can interrogate samples at a fine spatial scale. Quantitative chemical information can be extracted using the transmitted and energy-resolved X-ray fluorescence channels simultaneously. Here we compare the relative merits of transmission and low-energy X-ray fluorescence detection of X-ray absorption for speciation and quantitative analysis of the spatial distribution of arsenic(V) within cell-mineral aggregates formed by Acidovorax sp. strain BoFeN1, an anaerobic nitrate-reducing Fe(II)-oxidizing β-proteobacteria isolated from the sediments of Lake Constance. This species is noted to be highly tolerant to high levels of As(V). Related, As-tolerant Acidovorax-strains have been found in As-contaminated groundwater wells in Bangladesh and Cambodia wherein they might influence the mobility of As by providing sorption sites which might have different properties as compared to chemically formed Fe-minerals. In addition to demonstrating the lower detection limits that are achieved with X-ray fluorescence relative to transmission detection in STXM, this study helps to gain insights into the mechanisms of As immobilization by biogenic Fe-mineral formation and to further the understanding of As-resistance of anaerobic Fe(II)-oxidizing bacteria.

  6. Long-term effects of prenatal x-ray of human females. II. Growth and development.

    PubMed

    Meyer, M B; Tonascia, J

    1981-09-01

    Experimental studies and studies of survivors of in-utero exposure to atomic bomb blasts have shown significant stunting of growth and mental retardation following these exposures. Central nervous system damage following very low doses of x-ray at around the time of birth has also been observed in experimental animals. This long term follow-up studies of 1458 human females exposed in utero to diagnostic x-rays and of 1458 matched unexposed controls studied in Baltimore, Maryland, included measurements of height, weight and school achievement. Women who had been exposed to x-rays in utero were significantly shorter in their mid-twenties than were their matched, unexposed controls, even after adjustment for other social and economic factors. However, additional follow-up revealed that mothers of exposed women were also shorter than the control mothers. Short stature appeared to be a selective factor for x-ray during pregnancy (mostly pelvimetry, 1947-1952). Mothers' and daughters' heights were similarly correctly among exposed and control mother-daughter pairs, suggesting that the height differences between exposed daughters and their controls were due to these selective factor rather than to any direct effect of radiation on growth. Exposed women reported poorer school achievement than control women. However, except for a higher proportion of exposed women leaving school because of pregnancy, these measurements were no longer significantly different when rates were simultaneously adjusted for socioeconomic differences between exposed and control women.

  7. High performance X-ray and neutron microfocusing optics. Phase II final report.

    SciTech Connect

    Gregory Hirsch

    2000-01-14

    The use of extremely small diameter x-ray beams at synchrotron radiation facilities has become an important experimental technique for investigators in many other scientific disciplines. While there have been several different optical elements developed for producing such microbeams, this SBIR project was concerned with one particular device: the tapered-monocapillary optic.

  8. The MUSIC of galaxy clusters - II. X-ray global properties and scaling relations

    NASA Astrophysics Data System (ADS)

    Biffi, V.; Sembolini, F.; De Petris, M.; Valdarnini, R.; Yepes, G.; Gottlöber, S.

    2014-03-01

    We present the X-ray properties and scaling relations of a large sample of clusters extracted from the Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC) data set. We focus on a sub-sample of 179 clusters at redshift z ˜ 0.11, with 3.2 × 1014 h-1 M⊙ < Mvir < 2 × 1015 h-1 M⊙, complete in mass. We employed the X-ray photon simulator PHOX to obtain synthetic Chandra observations and derive observable-like global properties of the intracluster medium (ICM), as X-ray temperature (TX) and luminosity (LX). TX is found to slightly underestimate the true mass-weighted temperature, although tracing fairly well the cluster total mass. We also study the effects of TX on scaling relations with cluster intrinsic properties: total (M500 and gas Mg,500 mass; integrated Compton parameter (YSZ) of the Sunyaev-Zel'dovich (SZ) thermal effect; YX = Mg,500 TX. We confirm that YX is a very good mass proxy, with a scatter on M500-YX and YSZ-YX lower than 5 per cent. The study of scaling relations among X-ray, intrinsic and SZ properties indicates that simulated MUSIC clusters reasonably resemble the self-similar prediction, especially for correlations involving TX. The observational approach also allows for a more direct comparison with real clusters, from which we find deviations mainly due to the physical description of the ICM, affecting TX and, particularly, LX.

  9. Distant Cluster Hunting. II; A Comparison of X-Ray and Optical Cluster Detection Techniques and Catalogs from the ROSAT Optical X-Ray Survey

    NASA Technical Reports Server (NTRS)

    Donahue, Megan; Scharf, Caleb A.; Mack, Jennifer; Lee, Y. Paul; Postman, Marc; Rosait, Piero; Dickinson, Mark; Voit, G. Mark; Stocke, John T.

    2002-01-01

    We present and analyze the optical and X-ray catalogs of moderate-redshift cluster candidates from the ROSA TOptical X-Ray Survey, or ROXS. The survey covers the sky area contained in the fields of view of 23 deep archival ROSA T PSPC pointings, 4.8 square degrees. The cross-correlated cluster catalogs were con- structed by comparing two independent catalogs extracted from the optical and X-ray bandpasses, using a matched-filter technique for the optical data and a wavelet technique for the X-ray data. We cross-identified cluster candidates in each catalog. As reported in Paper 1, the matched-filter technique found optical counter- parts for at least 60% (26 out of 43) of the X-ray cluster candidates; the estimated redshifts from the matched filter algorithm agree with at least 7 of 1 1 spectroscopic confirmations (Az 5 0.10). The matched filter technique. with an imaging sensitivity of ml N 23, identified approximately 3 times the number of candidates (155 candidates, 142 with a detection confidence >3 u) found in the X-ray survey of nearly the same area. There are 57 X-ray candidates, 43 of which are unobscured by scattered light or bright stars in the optical images. Twenty-six of these have fairly secure optical counterparts. We find that the matched filter algorithm, when applied to images with galaxy flux sensitivities of mI N 23, is fairly well-matched to discovering z 5 1 clusters detected by wavelets in ROSAT PSPC exposures of 8000-60,000 s. The difference in the spurious fractions between the optical and X-ray (30%) and IO%, respectively) cannot account for the difference in source number. In Paper I, we compared the optical and X-ray cluster luminosity functions and we found that the luminosity functions are consistent if the relationship between X-ray and optical luminosities is steep (Lx o( L&f). Here, in Paper 11, we present the cluster catalogs and a numerical simulation of the ROXS. We also present color-magnitude plots for several of the cluster

  10. Quasi-periodic Variations in X-Ray Emission and Long-term Radio Observations: Evidence for a Two-component Jet in Sw J1644+57

    NASA Astrophysics Data System (ADS)

    Wang, Jiu-Zhou; Lei, Wei-Hua; Wang, Ding-Xiong; Zou, Yuan-Chuan; Zhang, Bing; Gao, He; Huang, Chang-Yin

    2014-06-01

    The continued observations of Sw J1644+57 in X-ray and radio bands accumulated a rich data set to study the relativistic jet launched in this tidal disruption event. The X-ray light curve of Sw J1644+57 from 5-30 days presents two kinds of quasi-periodic variations: a 200 s quasi-periodic oscillation (QPO) and a 2.7 day quasi-periodic variation. The latter has been interpreted by a precessing jet launched near the Bardeen-Petterson radius of a warped disk. Here we suggest that the ~200 s QPO could be associated with a second, narrower jet sweeping the observer line-of-sight periodically, which is launched from a spinning black hole in the misaligned direction with respect to the black hole's angular momentum. In addition, we show that this two-component jet model can interpret the radio light curve of the event, especially the re-brightening feature starting ~100 days after the trigger. From the data we infer that inner jet may have a Lorentz factor of Γj ~ 5.5 and a kinetic energy of E k, iso ~ 3.0 × 1052 erg, while the outer jet may have a Lorentz factor of Γj ~ 2.5 and a kinetic energy of E k, iso ~ 3.0 × 1053 erg.

  11. Quasi-periodic variations in x-ray emission and long-term radio observations: Evidence for a two-component jet in Sw J1644+57

    SciTech Connect

    Wang, Jiu-Zhou; Lei, Wei-Hua; Wang, Ding-Xiong; Zou, Yuan-Chuan; Huang, Chang-Yin; Zhang, Bing; Gao, He E-mail: dxwang@hust.edu.cn E-mail: zhang@physics.unlv.edu

    2014-06-10

    The continued observations of Sw J1644+57 in X-ray and radio bands accumulated a rich data set to study the relativistic jet launched in this tidal disruption event. The X-ray light curve of Sw J1644+57 from 5-30 days presents two kinds of quasi-periodic variations: a 200 s quasi-periodic oscillation (QPO) and a 2.7 day quasi-periodic variation. The latter has been interpreted by a precessing jet launched near the Bardeen-Petterson radius of a warped disk. Here we suggest that the ∼200 s QPO could be associated with a second, narrower jet sweeping the observer line-of-sight periodically, which is launched from a spinning black hole in the misaligned direction with respect to the black hole's angular momentum. In addition, we show that this two-component jet model can interpret the radio light curve of the event, especially the re-brightening feature starting ∼100 days after the trigger. From the data we infer that inner jet may have a Lorentz factor of Γ{sub j} ∼ 5.5 and a kinetic energy of E {sub k,} {sub iso} ∼ 3.0 × 10{sup 52} erg, while the outer jet may have a Lorentz factor of Γ{sub j} ∼ 2.5 and a kinetic energy of E{sub k,} {sub iso} ∼ 3.0 × 10{sup 53} erg.

  12. A Coordinated X-Ray and Optical Campaign of the Nearby Massive Binary Sigma Orionis Aa. II; X-Ray Variability

    NASA Technical Reports Server (NTRS)

    Nichols, J.; Huenemoerder, D. P.; Corcoran, M. F.; Waldron, W.; Naze, Y; Pollock, A. M. T.; Moffat, A. F. J.; Lauer, J.; Shenar, T.; Russell, C. M. P.; Richardson, N. D.; Pablo, H.; Evans, N. R.; Hamaguchi, K.; Gull, T.; Hamann, W.-R.; Oskinova, L.; Ignace, R.; Hoffman, Jennifer L.; Hole, K. T.; Lomax, J. R.

    2015-01-01

    We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution gratings spectral dataset of the Sigma Ori Aa binary system. The four observations, obtained with Chandra ACIS HETGS, have a total exposure time of approximately 479 kiloseconds and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range 5-25 angstroms is confirmed, with maximum amplitude of about plus or minus 15 percent within a single approximately 125 kiloseconds observation. Periods of 4.76 days and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in flux level throughout the 9-day observational campaign. Using 40 kiloseconds contiguous spectra derived from the original observations, we investigate variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S XV, Si XIII, and Ne IX. For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at phi equals 0.0 when the secondary Aa2 is at inferior conjunction. We use the results of an SPH radiative transfer code model, customized for this project, to relate the presence of a low density cavity in the primary stellar wind embedded shock that is associated with the secondary star to the emission line width variability.

  13. DICHOTOMY OF SOLAR CORONAL JETS: STANDARD JETS AND BLOWOUT JETS

    SciTech Connect

    Moore, Ronald L.; Cirtain, Jonathan W.; Sterling, Alphonse C.; Falconer, David A.

    2010-09-01

    By examining many X-ray jets in Hinode/X-Ray Telescope coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H{alpha} macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major coronal mass ejections. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 A snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T {approx} 10{sup 4} - 10{sup 5} K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  14. Multitone harmonic-balance simulations of an x-ray transition-edge sensor characterized at BESSY II

    SciTech Connect

    Rostem, K.; Goldie, D. J.; Withington, S.; Hoevers, H. F. C.; Gottardi, L.; Kuur, J. van der

    2010-07-15

    We present multitone harmonic-balance (MTHB) simulations of a Ti-Au x-ray transition-edge sensor (TES) microcalorimeter in a 5x5 pixel spectrometer array. The dynamic response of the TES microcalorimeter under simulation has been extremely well characterized at the BESSY II Synchrotron Radiation Facility in Berlin. We compare our simulated results directly with these measurements, and show that the MTHB algorithm is able to simulate to great accuracy the dynamic behavior of the TES, even when saturated by 6 keV photons. In this paper, we provide a detailed account of the MTHB simulations, and discuss the impact of this work on future missions such as the International X-ray Observatory.

  15. Subpicosecond 41.8-nm X-ray laser in the plasma produced by femtosecond laser irradiation of a xenon cluster jet

    SciTech Connect

    Ivanova, E P

    2012-12-31

    Model calculations are performed of the radiation gain for the 4d5d (J = 0) - 4d5p (J = 1) transition with a wavelength of 41.8 nm in Pd-like xenon ions in the plasma produced by femtosecond laser irradiation of a xenon cluster jet. Conditions for the excitation of an ultrashort-pulse ({approx}1 ps) X-ray laser are discussed. (lasers)

  16. The X-Ray Zurich Environmental Study (X-ZENS). II. X-Ray Observations of the Diffuse Intragroup Medium in Galaxy Groups

    NASA Astrophysics Data System (ADS)

    Miniati, Francesco; Finoguenov, Alexis; Silverman, John D.; Carollo, Marcella; Cibinel, Anna; Lilly, Simon J.; Schawinski, Kevin

    2016-03-01

    We present the results of a pilot XMM-Newton and Chandra program aimed at studying the diffuse intragroup medium (IGM) of optically selected nearby groups from the Zurich ENvironmental Study (ZENS) catalog. The groups are in a narrow mass range about {10}13 {M}⊙ , a mass scale at which the interplay between the IGM and the group member galaxies is still largely unprobed. X-ray emission from the IGM is detected in the energy band 0.5-2 keV with flux ≤slant {10}-13 erg s-1 cm-2, which is one order of magnitude fainter than for typical ROSAT groups (RASS). For many groups, we set upper limits on the X-ray luminosity, indicating that the detections are likely probing the upper envelope of the X-ray emitting groups. We find that weighting the group halo mass by the fraction of the total stellar mass locked in the bulge galaxy components might reduce the bias of mass estimates based on the total optical luminosity with respect to the X-ray mass estimates, (consistent with Andreon, at larger mass scales). We measure a stellar mass fraction with a median value of about 1%, with a contribution from the most massive galaxies between 30% and 50%. Optical and X-ray data often give complementary answers concerning the dynamical state of the groups, and are essential for a complete picture of the group system. Extending this pilot program to a larger sample of groups is necessary to unveil any imprint of interaction between member galaxies and IGM in halo potentials of key importance for environmentally driven galactic evolution.

  17. Ensemble X-ray variability of active galactic nuclei. II. Excess variance and updated structure function

    NASA Astrophysics Data System (ADS)

    Vagnetti, F.; Middei, R.; Antonucci, M.; Paolillo, M.; Serafinelli, R.

    2016-09-01

    Context. Most investigations of the X-ray variability of active galactic nuclei (AGN) have been concentrated on the detailed analyses of individual, nearby sources. A relatively small number of studies have treated the ensemble behaviour of the more general AGN population in wider regions of the luminosity-redshift plane. Aims: We want to determine the ensemble variability properties of a rich AGN sample, called Multi-Epoch XMM Serendipitous AGN Sample (MEXSAS), extracted from the fifth release of the XMM-Newton Serendipitous Source Catalogue (XMMSSC-DR5), with redshift between ~0.1 and ~5, and X-ray luminosities in the 0.5-4.5 keV band between ~1042 erg/s and ~1047 erg/s. Methods: We urge caution on the use of the normalised excess variance (NXS), noting that it may lead to underestimate variability if used improperly. We use the structure function (SF), updating our previous analysis for a smaller sample. We propose a correction to the NXS variability estimator, taking account of the light curve duration in the rest frame on the basis of the knowledge of the variability behaviour gained by SF studies. Results: We find an ensemble increase of the X-ray variability with the rest-frame time lag τ, given by SF ∝ τ0.12. We confirm an inverse dependence on the X-ray luminosity, approximately as SF ∝ LX-0.19. We analyse the SF in different X-ray bands, finding a dependence of the variability on the frequency as SF ∝ ν-0.15, corresponding to a so-called softer when brighter trend. In turn, this dependence allows us to parametrically correct the variability estimated in observer-frame bands to that in the rest frame, resulting in a moderate (≲15%) shift upwards (V-correction). Conclusions: Ensemble X-ray variability of AGNs is best described by the structure function. An improper use of the normalised excess variance may lead to an underestimate of the intrinsic variability, so that appropriate corrections to the data or the models must be applied to prevent

  18. Chandra Phase-Resolved X-ray Spectroscopy of the Crab Pulsar II

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; Tennant, Allyn F.; Yakovlev, Dimitry G.; Harding, Alice; Zavlin, Vyacheslav E.; Elsner, Ronald F.; Becker, Werner

    2012-01-01

    We present a new study of the X-ray spectral properties of the Crab Pulsar. The superb angular resolution of the Chandra X-ray Observatory enables distinguishing the pulsar from the surrounding nebulosity. Analysis of the spectrum as a function of pulse phase allows the least-biased measure of interstellar X-ray extinction due primarily to photoelectric absorption and secondarily to scattering by dust grains in the direction of the Crab Nebula. We modify previous findings that the line-of-sight to the Crab is under-abundant in oxygen and provide measurements with improved accuracy and less bias. Using the abundances and cross sections from Wilms, Allen & McCray (2000) we find [O/H] = (5.28+\\-0.28) x 10(exp -4) (4.9 x 10(exp -4) is solar abundance). \\rVe also measure for the first time the impact of scattering of flux out of the image by interstellar grains. \\rYe find T(sub scat) = 0.147+/-0.043. Analysis of the spectrum as a function of pulse phase also measures the X-ray spectral index even at pulse minimum - albeit with increasing statistical uncertainty. The spectral variations are, by and large, consistent with a sinusoidal variation. The only significant variation from the sinusoid occurs over the same phase range as some rather abrupt behavior in the optical polarization magnitude and position angle. We compare these spectral variations to those observed in Gamma-rays and conclude that our measurements are both a challenge and a guide to future modeling and will thus eventually help us understand pair cascade processes in pulsar magnetospheres. The data were also used to set new. and less biased, upper limits to the surface temperature of the neutron star for different models of the neutron star atmosphere.

  19. X-ray irradiated model stellar atmospheres. II. Comprehensive treatment of Compton scattering

    NASA Astrophysics Data System (ADS)

    Madej, J.; Rózańska, A.

    2000-11-01

    We present equations and details of the computer code for model atmosphere computations, in which we include both nonzero external illumination by very hard X-rays, and Compton scattering opacity and emissivity. We assume both radiative and hydrostatic equilibrium, and LTE equation of state. The code solves simultaneously transfer of thermal radiation emitted by a hot main sequence stellar atmosphere and incident hard X-rays of photon energy approaching electron rest mass. The equation of radiative transfer and remaining equations of equilibrium contain Compton scattering terms appropriate for scattering of photons of arbitrarily large initial energies. In our paper we consider Compton scattering of photons of energy up to 400 keV on free electrons in fully relativistic thermal motion. In this paper we consider illumination of a B3 V type star by isotropic X-rays of diluted thermal spectral distribution with temperature Trad=108 K. Two series of models are computed, hydrogen-helium models and iron rich models. Our results demonstrate, that the external illumination causes extreme temperature rise at least in the uppermost layers. Outgoing spectra exhibit: big UV bump, numerous H, He, and Fe b-f opacity jumps mostly in emission, and also reflected incident spectrum with Compton cut-off. The model spectra also reflect qualitatively spectral properties of the active galactic nuclei (AGN).

  20. Structure of the Mn complex in photosystem II: Insights from x-ray spectroscopy

    SciTech Connect

    Yachandra, Vittal K.

    2002-04-02

    We have used Mn K-edge absorption and Kb emission spectroscopies to determine the oxidation states of the Mn complex in the various S-states. We have started exploring the new technique of resonant inelastic X-ray scattering spectroscopy (RIXS); this technique can be characterized as a Raman process that uses K-edge energies (1s to 4p, {approx}6550 eV) to obtain L-edge-like spectra (2p to 3d, {approx}650 eV). The relevance of these data to the oxidation states and structure of the Mn complex is presented. We have obtained EXAFS data from the S0 and S3 states and observed heterogeneity in the Mn-Mn distances, leading us to conclude that there may be three rather than two di-(mu)-oxo bridged units present per tetranuclear Mn cluster. In addition, we have obtained data using Ca/Sr X-ray spectroscopy that provide evidence for a heteronuclear Mn/Ca cluster. The possibility of three di-(mu)-oxo-bridged Mn Mn moieties and the proximity of Ca is incorporated into developing structural models for the Mn cluster. The involvement of bridging and terminal O ligands of Mn in the mechanism of oxygen evolution is discussed in the context of our X-ray spectroscopy results.

  1. An XMM-Newton Observation of 4U1755-33 in Quiescence: Evidence for a Fossil X-Ray Jet

    NASA Technical Reports Server (NTRS)

    Angelini, Lorella; White, Nicholas E.

    2003-01-01

    We report an XMM-Newton observation of the Low mass X-ray Binary (LMXB) and black hole candidate 4U1755-33. This source had been a bright persistent source for at least 25 yrs, but in 1995 entered an extended quiescent phase. 4U1755-33 was not detected with an upper limit to the 2-10 keV luminosity of 5 x 10(exp 31) d(sup 2) (sub 4kpc) ergs per second (where d(sub 4kpc) is the distance in units of 4 kpc) - consistent with the luminosity of other black hole candidates in a quiescent state. An unexpected result is the discovery of a narrow 7 arc min long X-ray jet centered on the position of 4Ul755-33. The spectrum of the jet is similar to that of jets observed from other galactic and extragalactic sources, and may have been ejected from 4Ul755-33 when it was bright. Jets are a feature of accreting black holes, and the detection of a fossil jet provides additional evidence supporting the black hole candidacy of 4U1755-33. The spectral properties of three bright serendipitous sources in the field are reported and it is suggested these are background active galactic nuclei sources.

  2. redMaPPer II: X-ray and SZ performance benchmarks for the SDSS catalog

    SciTech Connect

    Rykoff, E. Rozo and E. S.

    2014-03-10

    We evaluate the performance of the Sloan Digital Sky Survey (SDSS) DR8 redMaPPer photometric cluster catalog by comparing it to overlapping X-ray- and Sunyaev-Zeldovich (SZ)-selected catalogs from the literature. We confirm that the redMaPPer photometric redshifts are nearly unbiased ((Δz) ≤ 0.005), have low scatter (σ {sub z} ≈ 0.006-0.02, depending on redshift), and have a low catastrophic failure rate (≈1%). Both the T{sub X} -λ and M {sub gas}-λ scaling relations are consistent with a mass scatter of σ{sub ln} {sub M|λ} ≈ 25%, albeit with a ≈1% outlier rate due to projection effects (λ is the cluster richness estimated employed by redMaPPer). This failure rate is somewhat lower than that expected for the full cluster sample but is consistent with the additional selection effects introduced by our reliance on X-ray and SZ selected reference cluster samples. Where the redMaPPer DR8 catalog is volume-limited (z ≤ 0.35), the catalog is 100% complete above T{sub X} ≳ 3.5 keV, and L{sub X} ≳ 2 × 10{sup 44} erg s{sup –1}, decreasing to 90% completeness at L{sub X} ≈ 10{sup 43} erg s{sup –1}. All rich (λ ≳ 100), low-redshift (z ≲ 0.25) redMaPPer clusters are X-ray-detected in the ROSAT All Sky Survey, and 86% of the clusters are correctly centered. Compared to other SDSS photometric cluster catalogs, redMaPPer has the highest completeness and purity, and the best photometric redshift performance, though some algorithms do achieve comparable performance to redMaPPer in subsets of the above categories and/or in limited redshift ranges. The redMaPPer richness is clearly the one that best correlates with X-ray temperature and gas mass. Most algorithms (including redMaPPer) have very similar centering performance as tested by comparing against X-ray centers, with only one exception which performs worse.

  3. redMaPPer II: X-Ray and SZ Performance Benchmarks for the SDSS Catalog

    NASA Astrophysics Data System (ADS)

    Rozo, E.; Rykoff, E. S.

    2014-03-01

    We evaluate the performance of the Sloan Digital Sky Survey (SDSS) DR8 redMaPPer photometric cluster catalog by comparing it to overlapping X-ray- and Sunyaev-Zeldovich (SZ)-selected catalogs from the literature. We confirm that the redMaPPer photometric redshifts are nearly unbiased (langΔzrang <= 0.005), have low scatter (σ z ≈ 0.006-0.02, depending on redshift), and have a low catastrophic failure rate (≈1%). Both the TX -λ and M gas-λ scaling relations are consistent with a mass scatter of σln M|λ ≈ 25%, albeit with a ≈1% outlier rate due to projection effects (λ is the cluster richness estimated employed by redMaPPer). This failure rate is somewhat lower than that expected for the full cluster sample but is consistent with the additional selection effects introduced by our reliance on X-ray and SZ selected reference cluster samples. Where the redMaPPer DR8 catalog is volume-limited (z <= 0.35), the catalog is 100% complete above TX >~ 3.5 keV, and LX >~ 2 × 1044 erg s-1, decreasing to 90% completeness at LX ≈ 1043 erg s-1. All rich (λ >~ 100), low-redshift (z <~ 0.25) redMaPPer clusters are X-ray-detected in the ROSAT All Sky Survey, and 86% of the clusters are correctly centered. Compared to other SDSS photometric cluster catalogs, redMaPPer has the highest completeness and purity, and the best photometric redshift performance, though some algorithms do achieve comparable performance to redMaPPer in subsets of the above categories and/or in limited redshift ranges. The redMaPPer richness is clearly the one that best correlates with X-ray temperature and gas mass. Most algorithms (including redMaPPer) have very similar centering performance as tested by comparing against X-ray centers, with only one exception which performs worse.

  4. A DEEP CHANDRA OBSERVATION OF THE GIANT H II REGION N11. I. X-RAY SOURCES IN THE FIELD

    SciTech Connect

    Nazé, Yaël; Wang, Q. Daniel; Chu, You-Hua; Gruendl, Robert; Oskinova, Lida

    2014-08-01

    A very sensitive X-ray investigation of the giant H II region N11 in the Large Megallanic Cloud was performed using the Chandra X-ray Observatory. The 300 ks observation reveals X-ray sources with luminosities down to 10{sup 32} erg s{sup –1}, increasing the number of known point sources in the field by more than a factor of five. Among these detections are 13 massive stars (3 compact groups of massive stars, 9 O stars, and one early B star) with log (L {sub X}/L {sub BOL}) ∼–6.5 to –7, which may suggest that they are highly magnetic or colliding-wind systems. On the other hand, the stacked signal for regions corresponding to undetected O stars yields log (L {sub X}/L {sub BOL}) ∼–7.3, i.e., an emission level comparable to similar Galactic stars despite the lower metallicity. Other point sources coincide with 11 foreground stars, 6 late-B/A stars in N11, and many background objects. This observation also uncovers the extent and detailed spatial properties of the soft, diffuse emission regions, but the presence of some hotter plasma in their spectra suggests contamination by the unresolved stellar population.

  5. Development of X-ray computed tomography inspection facility for the H-II solid rocket boosters

    NASA Astrophysics Data System (ADS)

    Sasaki, M.; Fujita, T.; Fukushima, Y.; Shimizu, M.; Itoh, S.; Satoh, A.; Miyamoto, H.

    The National Space Development Agency of Japan (NASDA) initiated the development of an X-ray computed tomography (CT) equipment for the H-II solid rocket boosters (SRBs) in 1987 for the purpose of minimizing inspection time and achieving high cost-effectiveness. The CT facility has been completed in Jan. 1991 in Tanegashima Space Center for the inspection of the SRBs transported from the manufacturer's factory to the launch site. It was first applied to the qualification model SRB from Feb. to Apr. in 1991. Through the CT inspection of the SRB, it has been confirmed that inspection time decreased significantly compared with the X-ray radiography method and that even an unskilled inspector could find various defects. As a result, the establishment of a new reliable inspection method for the SRB has been verified. In this paper, the following are discussed: (1) the defect detectability of the CT equipment using a dummy SRB with various artificial defects, (2) the performance comparison between the CT method and the X-ray radiography method, (3) the reliability of the CT equipment, and (4) the radiation shield design of the nondestructive test building.

  6. Ligand-field symmetry effects in Fe(II) polypyridyl compounds probed by transient X-ray absorption spectroscopy

    SciTech Connect

    Cho, Hana; Strader, Matthew L.; Hong, Kiryong; Jamula, Lindsey; Kim, Tae Kyu; Groot, Frank M. F. de; McCusker, James K.; Schoenlein, Robert W.; Huse, Nils

    2012-02-28

    Ultrafast excited-state evolution in polypyridyl FeII complexes are of fundamental interest for understanding the origins of the sub-ps spin-state changes that occur upon photoexcitation of this class of compounds as well as for the potential impact such ultrafast dynamics have on incorporation of these compounds in solar energy conversion schemes or switchable optical storage technologies. We have demonstrated that ground-state and, more importantly, ultrafast time-resolved x-ray absorption methods can offer unique insights into the interplay between electronic and geometric structure that underpin the photo-induced dynamics of this class of compounds. The present contribution examines in greater detail how the symmetry of the ligand field surrounding the metal ion can be probed using these x-ray techniques. In particular, we show that steady-state K-edge spectroscopy of the nearest-neighbour nitrogen atoms reveals the characteristic chemical environment of the respective ligands and suggests an interesting target for future charge-transfer femtosecond and attosecond spectroscopy in the x-ray water window.

  7. Addendum: ``Chandra X-Ray Imaging and Spectroscopy of the M87 Jet and Nucleus'' (ApJ, 568, 133 [2002])

    NASA Astrophysics Data System (ADS)

    Wilson, A. S.; Yang, Y.

    2004-07-01

    consequences of the too-hard X-ray spectra that we obtained, and are here withdrawn. A more complete discussion of the Chandra X-ray observations of the jet of M87, and their relation to observations in other wavebands, will be presented elsewhere (E. S. Perlman & A. S. Wilson, in preparation).

  8. Multiwavelength modeling the SED of supersoft X-ray sources. II. RS Ophiuchi: From the explosion to the SSS phase

    NASA Astrophysics Data System (ADS)

    Skopal, A.

    2015-04-01

    RS Oph is a recurrent symbiotic nova that undergoes nova-like outbursts on a time scale of 20 yr. Its two last eruptions (1985 and 2006) were subject of intensive multiwavelengths observational campaign from the X-rays to the radio. This contribution aims to determine physical parameters and the ionization structure of the nova from its explosion to the first emergence of the supersoft X-rays (day 26) by using the method of multiwavelength modeling the SED. From the very beginning of the eruption, the model SED revealed the presence of both a strong stellar and nebular component of radiation in the spectrum. During the first 4 days, the nova evinced a biconical ionization structure. The ∼8200 K warm and 160-200 R⊙ extended pseudophotosphere encompassed the white dwarf (WD) around its equator to the latitude > 40 ° . The remaining space around the WD's poles was ionized, producing a strong nebular continuum with the emission measure EM ∼ 2.3 ×1062 cm-3 via the fast wind from the WD. The luminosity of the burning WD was highly super-Eddington for the whole investigated period. The wind mass loss at rates of 10-4-10-5M⊙yr-1 and the presence of jets suggest an accretion throughout a disk at a high rate, which can help to sustain the super-Eddington luminosity of the accretor for a long time.

  9. High-Resolution Imaging of X-Ray Jets in Inner Lobes of Centaurus A (NGC5128) using Chandra HRC-I Data and Some Comparison with its Radio Jets

    NASA Astrophysics Data System (ADS)

    Somanah, R.

    2009-10-01

    We present high angular resolution X-ray images from Chandra HRC-I observations of the X-ray jet in the nearby radio galaxy Centaurus A (NGC5128). Since the HRC data does not have spectral resolution, we chose a monochromatic or monoenergetic energy of 1.5 KeV as it is in a range which corresponds to the temperature of the jets and this also removes much of the strong emission from the heavily absorbed X-ray nucleus without compromising the soft emission from the jet. We find that the X-ray emission from the jet is composed of a low surface brightness diffuse component extending continuously from within at least 50 pc of the active nucleus into the NE radio lobe 3 Kpc from the nucleus, along with a dozen discrete compact knots. We find that there are small differences between the X-ray and radio morphologies on the inner jet at the arcsec level which might be due to the fact that there are two different populations of relativistic electrons responsible from the radio and X-ray emissions. Nous présentons des images à haute résolution angulaire dans la gamme des rayons-X. Elles proviennent des observations par le satellite Chandra HRC-I, du jet en rayon-X au sein de la radiogalaxie Centaurus A (NGC5128). Du fait que le HRC est dépourvu de résolution spectrale, nous nous intéressons à la gamme mono énergétique de 1.5 kev ; située dans la plage d'énergies correspondant à la température des jets. La gamme de 1.5 kev présente aussi l'avantage d'éliminer les rayons-X "durs" provenant du noyau, sana compromettre les rayons-X "doux" du jet. Nous établissons que le rayonnement X du jet est fait d'une composante a faible luminosité de surface. Cette composant s'étale de façon continue a partir de 50 pc du noyau actif jusqu'à l'intérieur du lobe NE situe a 3 kpc du noyau, en même temps qu une traîne discontinue faite d'une douzaine de noeuds compacts.

  10. Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

    NASA Technical Reports Server (NTRS)

    Moore, R. L.; Cirtain, J. W.; Sterling, A. C.; Falconer, D. A.

    2010-01-01

    By examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H alpha macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Angstrom snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T 10(exp 4) - 10(exp 5) K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  11. A Jet Break in the X-Ray Light Curve of Short GRB 111020A: Implications for Energetics and Rates

    NASA Astrophysics Data System (ADS)

    Fong, W.; Berger, E.; Margutti, R.; Zauderer, B. A.; Troja, E.; Czekala, I.; Chornock, R.; Gehrels, N.; Sakamoto, T.; Fox, D. B.; Podsiadlowski, P.

    2012-09-01

    We present broadband observations of the afterglow and environment of the short GRB 111020A. An extensive X-ray light curve from Swift/XRT, XMM-Newton, and Chandra, spanning ~100 s to 10 days after the burst, reveals a significant break at δt ≈ 2 days with pre- and post-break decline rates of α X, 1 ≈ -0.78 and α X, 2 <~ -1.7, respectively. Interpreted as a jet break, we infer a collimated outflow with an opening angle of θ j ≈ 3°-8°. The resulting beaming-corrected γ-ray (10-1000 keV band) and blast-wave kinetic energies are (2-3) × 1048 erg and (0.3-2) × 1049 erg, respectively, with the range depending on the unknown redshift of the burst. We report a radio afterglow limit of <39 μJy (3σ) from Expanded Very Large Array observations that, along with our finding that ν c < ν X , constrains the circumburst density to n 0 ~ 0.01-0.1 cm-3. Optical observations provide an afterglow limit of i >~ 24.4 mag at 18 hr after the burst and reveal a potential host galaxy with i ≈ 24.3 mag. The subarcsecond localization from Chandra provides a precise offset of 0farcs80 ± 0farcs11 (1σ) from this galaxy corresponding to an offset of 5-7 kpc for z = 0.5-1.5. We find a high excess neutral hydrogen column density of (7.5 ± 2.0) × 1021 cm-2 (z = 0). Our observations demonstrate that a growing fraction of short gamma-ray bursts (GRBs) are collimated, which may lead to a true event rate of >~ 100-1000 Gpc-3 yr-1, in good agreement with the NS-NS merger rate of ≈200-3000 Gpc-3 yr-1. This consistency is promising for coincident short GRB-gravitational wave searches in the forthcoming era of Advanced LIGO/VIRGO.

  12. A Jet Break in the X-ray Light Curve of Short GRB 111020A: Implications for Energetics and Rates

    NASA Technical Reports Server (NTRS)

    Fong, W.; Berger, E.; Margutti, R.; Zauderer, B. A.; Troja, E.; Czekala, I.; Chornock, R.; Gehrels, N.; Sakamoto, T.; Fox, D. B.; Podsiadlowski, P.

    2012-01-01

    We present broadband observations of the afterglow and environment of the short GRB 111020A. An extensive X-ray light curve from Swift/XRT, XMM-Newton, and Chandra, spanning approx.100 s to 10 days after the burst, reveals a significant break at (delta)t approx. = 2 days with pre- and post-break decline rates of (alpha)X,1 approx. = -0.78 and (alpha)X,2 < or approx. 1.7, respectively. Interpreted as a jet break, we infer a collimated outflow with an opening angle of (theta)j approx. = 3deg - 8deg. The resulting beaming-corrected gamma-ray (10-1000 keV band) and blast-wave kinetic energies are (2-3) x 10(exp 48) erg and (0.3-2) x 10(exp 49) erg, respectively, with the range depending on the unknown redshift of the burst. We report a radio afterglow limit of <39 micro-Jy (3(sigma)) from Expanded Very Large Array observations that, along with our finding that v(sub c) < v(sub X), constrains the circumburst density to n(sub 0) approx.0.01 0.1/cu cm. Optical observations provide an afterglow limit of i > or approx.24.4 mag at 18 hr after the burst and reveal a potential host galaxy with i approx. = 24.3 mag. The subarcsecond localization from Chandra provides a precise offset of 0".80+/-0".11 (1(sigma))from this galaxy corresponding to an offset of 5.7 kpc for z = 0.5-1.5. We find a high excess neutral hydrogen column density of (7.5+/-2.0) x 10(exp 21)/sq cm (z = 0). Our observations demonstrate that a growing fraction of short gamma-ray bursts (GRBs) are collimated, which may lead to a true event rate of > or approx.100-1000 Gpc(sup -3)/yr, in good agreement with the NS-NS merger rate of approx. = 200-3000 Gpc(sup -3)/ yr. This consistency is promising for coincident short GRB-gravitational wave searches in the forthcoming era of Advanced LIGO/VIRGO.

  13. A JET BREAK IN THE X-RAY LIGHT CURVE OF SHORT GRB 111020A: IMPLICATIONS FOR ENERGETICS AND RATES

    SciTech Connect

    Fong, W.; Berger, E.; Margutti, R.; Zauderer, B. A.; Czekala, I.; Chornock, R.; Troja, E.; Gehrels, N.; Sakamoto, T.; Fox, D. B.; Podsiadlowski, P.

    2012-09-10

    We present broadband observations of the afterglow and environment of the short GRB 111020A. An extensive X-ray light curve from Swift/XRT, XMM-Newton, and Chandra, spanning {approx}100 s to 10 days after the burst, reveals a significant break at {delta}t Almost-Equal-To 2 days with pre- and post-break decline rates of {alpha}{sub X,1} Almost-Equal-To -0.78 and {alpha}{sub X,2} {approx}< -1.7, respectively. Interpreted as a jet break, we infer a collimated outflow with an opening angle of {theta}{sub j} Almost-Equal-To 3 Degree-Sign -8 Degree-Sign . The resulting beaming-corrected {gamma}-ray (10-1000 keV band) and blast-wave kinetic energies are (2-3) Multiplication-Sign 10{sup 48} erg and (0.3-2) Multiplication-Sign 10{sup 49} erg, respectively, with the range depending on the unknown redshift of the burst. We report a radio afterglow limit of <39 {mu}Jy (3{sigma}) from Expanded Very Large Array observations that, along with our finding that {nu}{sub c} < {nu}{sub X}, constrains the circumburst density to n{sub 0} {approx} 0.01-0.1 cm{sup -3}. Optical observations provide an afterglow limit of i {approx}> 24.4 mag at 18 hr after the burst and reveal a potential host galaxy with i Almost-Equal-To 24.3 mag. The subarcsecond localization from Chandra provides a precise offset of 0.''80 {+-} 0.''11 (1{sigma}) from this galaxy corresponding to an offset of 5-7 kpc for z 0.5-1.5. We find a high excess neutral hydrogen column density of (7.5 {+-} 2.0) Multiplication-Sign 10{sup 21} cm{sup -2} (z = 0). Our observations demonstrate that a growing fraction of short gamma-ray bursts (GRBs) are collimated, which may lead to a true event rate of {approx}> 100-1000 Gpc{sup -3} yr{sup -1}, in good agreement with the NS-NS merger rate of Almost-Equal-To 200-3000 Gpc{sup -3} yr{sup -1}. This consistency is promising for coincident short GRB-gravitational wave searches in the forthcoming era of Advanced LIGO/VIRGO.

  14. RELATIONSHIP BETWEEN THE KINETIC POWER AND BOLOMETRIC LUMINOSITY OF JETS: LIMITATION FROM BLACK HOLE X-RAY BINARIES, ACTIVE GALACTIC NUCLEI, AND GAMMA-RAY BURSTS

    SciTech Connect

    Ma, Renyi; Hou, Shujin; Xie, Fu-Guo E-mail: fgxie@shao.ac.cn

    2014-01-01

    The correlation between the kinetic power P {sub jet} and intrinsic bolometric luminosity L {sub jet} of jets may reveal the underlying jet physics in various black hole systems. Based on the recent work by Nemmen et al., we re-investigate this correlation with additional sources of black hole X-ray binaries (BXBs) in hard/quiescent states and low-luminosity active galactic nuclei (LLAGNs). The new sample includes 29 sets of data from 7 BXBs and 20 LLAGNs, with P {sub jet} and L {sub jet} being derived from spectral modeling of the quasi-simultaneous multi-band spectra under the accretion jet scenario. Compared to previous works, the range of luminosity is now enlarged to more than 20 decades, i.e., from ∼10{sup 31} erg s{sup –1} to ∼10{sup 52} erg s{sup –1}, which allows for better constraining of the correlation. One notable result is that the jets in BXBs and LLAGNs almost follow the same P {sub jet}-L {sub jet} correlation that was obtained from blazars and gamma-ray bursts. The slope indices we derived are 1.03 ± 0.01 for the whole sample, 0.85 ± 0.06 for the BXB subsample, 0.71 ± 0.11 for the LLAGN subsample, and 1.01 ± 0.05 for the LLAGN-blazar subsample, respectively. The correlation index around unit implies the independence of jet efficiency on the luminosity or kinetic power. Our results may further support the hypothesis that similar physical processes exist in the jets of various black hole systems.

  15. X-ray absorption spectral studies of copper (II) mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Soni, B.; Dar, Davood Ah; Shrivastava, B. D.; Prasad, J.; Srivastava, K.

    2014-09-01

    X-ray absorption spectra at the K-edge of copper have been studied in two copper mixed ligand complexes, one having tetramethyethylenediamine (tmen) and the other having tetraethyethylenediamine (teen) as one of the ligands. The spectra have been recorded at BL-8 dispersive extended X-ray absorption fine structure (EXAFS) beamline at the 2.5 GeV INDUS- 2 synchrotron, RRCAT, Indore, India. The data obtained has been processed using the data analysis program Athena. The energy of the K-absorption edge, chemical shift, edge-width and shift of the principal absorption maximum in the complexes have been determined and discussed. The values of these parameters have been found to be approximately the same in both the complexes indicating that the two complexes possess similar chemical environment around the copper metal atom. The chemical shift has been utilized to estimate effective nuclear charge on the absorbing atom. The normalized EXAFS spectra have been Fourier transformed. The position of the first peak in the Fourier transform gives the value of first shell bond length, which is shorter than the actual bond length because of energy dependence of the phase factors in the sine function of the EXAFS equation. This distance is thus the phase- uncorrected bond length. Bond length has also been determined by Levy's, Lytle's and Lytle, Sayers and Stern's (LSS) methods. The results obtained from LSS and the Fourier transformation methods are comparable with each other, since both are phase uncorrected bond lengths.

  16. Highly efficient tabletop x-ray laser at {lambda}=41.8 nm in Pd-like xenon pumped by optical-field ionization in a cluster jet

    SciTech Connect

    Ivanova, E. P.

    2011-10-15

    The atomic-kinetic calculations of gain at 41.8 nm in Pd-like xenon are performed. The interpretation of known experiments has proved that x-ray laser in Pd-like xenon is feasible in the extremely wide range of atomic densities: 10{sup 17}{<=}[Xe{sup 8+}]{<=} 3 x 10{sup 19} cm{sup -3}. This result is due to the large cross sections (and rates) of level excitations in Pd-like xenon by electron impact. We propose a highly efficient tabletop x-ray laser pumped by optical-field ionization in a xenon cluster jet. The efficiency of {approx}0.5% is possible with a pump laser pulse energy of {>=}0.001 J and an intensity of {approx}10{sup 16} W/cm{sup 2}.

  17. Preliminary joint X-ray and neutron protein crystallographic studies of endoxylanase II from the fungus Trichoderma longibrachiatum.

    PubMed

    Kovalevsky, Andrey Y; Hanson, B Leif; Seaver, Sean; Fisher, S Zoë; Mustyakimov, Marat; Langan, Paul

    2011-02-01

    Room-temperature X-ray and neutron diffraction data were measured from a family 11 endoxylanase holoenzyme (XynII) originating from the filamentous fungus Trichoderma longibrachiatum to 1.55 Å resolution using a home source and to 1.80 Å resolution using the Protein Crystallography Station at LANSCE. Crystals of XynII, which is an important enzyme for biofuel production, were grown at pH 8.5 in order to examine the effect of basic conditions on the protonation-state distribution in the active site and throughout the protein molecule and to provide insights for rational engineering of catalytically improved XynII for industrial applications.

  18. X-ray damage to the Mn4Ca complex in single crystals of photosystem II: a case study for metalloprotein crystallography.

    PubMed

    Yano, Junko; Kern, Jan; Irrgang, Klaus-Dieter; Latimer, Matthew J; Bergmann, Uwe; Glatzel, Pieter; Pushkar, Yulia; Biesiadka, Jacek; Loll, Bernhard; Sauer, Kenneth; Messinger, Johannes; Zouni, Athina; Yachandra, Vittal K

    2005-08-23

    X-ray absorption spectroscopy was used to measure the damage caused by exposure to x-rays to the Mn(4)Ca active site in single crystals of photosystem II as a function of dose and energy of x-rays, temperature, and time. These studies reveal that the conditions used for structure determination by x-ray crystallography cause serious damage specifically to the metal-site structure. The x-ray absorption spectra show that the structure changes from one that is characteristic of a high-valent Mn(4)(III(2),IV(2)) oxo-bridged Mn(4)Ca cluster to that of Mn(II) in aqueous solution. This damage to the metal site occurs at a dose that is more than one order of magnitude lower than the dose that results in loss of diffractivity and is commonly considered safe for protein crystallography. These results establish quantitative x-ray dose parameters that are applicable to redox-active metalloproteins. This case study shows that a careful evaluation of the structural intactness of the active site(s) by spectroscopic techniques can validate structures derived from crystallography and that it can be a valuable complementary method before structure-function correlations of metalloproteins can be made on the basis of high-resolution x-ray crystal structures.

  19. NUMERICAL SIMULATIONS OF RADIATIVE MAGNETIZED HERBIG-HARO JETS: THE INFLUENCE OF PRE-IONIZATION FROM X-RAYS ON EMISSION LINES

    SciTech Connect

    Tesileanu, O.; Mignone, A.; Massaglia, S.; Bacciotti, F. E-mail: mignone@ph.unito.it E-mail: fran@arcetri.astro.it

    2012-02-10

    We investigate supersonic, axisymmetric magnetohydrodynamic jets with a time-dependent injection velocity by numerical simulations with the PLUTO code. Using a comprehensive set of parameters, we explore different jet configurations in the attempt to construct models that can be directly compared to observational data of microjets. In particular, we focus our attention on the emitting properties of traveling knots and construct, at the same time, accurate line intensity ratios and surface brightness maps. Direct comparison of the resulting brightness and line intensity ratios distributions with observational data of microjets shows that a closer match can be obtained only when the jet material is pre-ionized to some degree. A very likely source for a pre-ionized medium is photoionization by X-ray flux coming from the central object.

  20. The jet of the BL Lacertae object PKS 2201+044: MAD near-IR adaptive optics observations and comparison with optical, radio and X-ray data

    NASA Astrophysics Data System (ADS)

    Liuzzo, E.; Falomo, R.; Treves, A.; Donato, D.; Sambruna, M.; Arcidiacono, C.; Giovannini, G.; Farinato, J.; Moretti, A.; Ragazzoni, R.; Diolaiti, E.; Lombini, M.; Brast, R.; Donaldson, R.; Kolb, J.; Marchetti, E.; Tordo, S.

    2011-04-01

    Context. Relativistic jets are a common feature of radio loud active galactic nuclei. Multifrequency observations are a unique tool to constrain their physics. Aims: We report on a detailed study of the properties of the jet of the nearby BL Lac object PKS 2201+044, one of the rare cases where the jet is detected from radio to X-rays. Methods: We use new adaptive optics near-IR observations of the source, obtained with the ESO multi-conjugated adaptive optics demonstrator (MAD) at the Very Large Telescope. These observations acquired in Ground-Layer Adaptive Optics mode are combined with images previously achieved by HST, VLA and Chandra to perform a morphological and photometric study of the jet. Results: We find a noticeable similarity in the morphology of the jet at radio, near-IR and optical wavelengths. We construct the spectral shape of the main knot of jet that appears dominated by synchrotron radiation. Conclusions: On the basis of the jet morphology and the weak lines spectrum we suggest that PKS 2201+044 belongs to the class of radio sources intermediate between FRIs and FRIIs.

  1. Synchrotron X-ray CT characterization of titanium parts fabricated by additive manufacturing. Part II. Defects.

    PubMed

    Scarlett, Nicola Vivienne Yorke; Tyson, Peter; Fraser, Darren; Mayo, Sheridan; Maksimenko, Anton

    2016-07-01

    Synchrotron X-ray tomography (SXRT) has been applied to the study of defects within three-dimensional printed titanium parts. These parts were made using the Arcam EBM(®) (electron beam melting) process which uses powdered titanium alloy, Ti64 (Ti alloy with approximately 6%Al and 4%V) as the feed and an electron beam for the sintering/welding. The experiment was conducted on the Imaging and Medical Beamline of the Australian Synchrotron. The samples represent a selection of complex shapes with a variety of internal morphologies. Inspection via SXRT has revealed a number of defects which may not otherwise have been seen. The location and nature of such defects combined with detailed knowledge of the process conditions can contribute to understanding the interplay between design and manufacturing strategy. This fundamental understanding may subsequently be incorporated into process modelling, prediction of properties and the development of robust methodologies for the production of defect-free parts.

  2. Using ACIS on the Chandra X-ray Observatory as a Particle Radiation Monitor II

    NASA Technical Reports Server (NTRS)

    Grant, C. E.; Ford, P. G.; Bautz, M. W.; ODell, S. L.

    2012-01-01

    The Advanced CCD Imaging Spectrometer is an instrument on the Chandra X-ray Observatory. CCDs are vulnerable to radiation damage, particularly by soft protons in the radiation belts and solar storms. The Chandra team has implemented procedures to protect ACIS during high-radiation events including autonomous protection triggered by an on-board radiation monitor. Elevated temperatures have reduced the effectiveness of the on-board monitor. The ACIS team has developed an algorithm which uses data from the CCDs themselves to detect periods of high radiation and a flight software patch to apply this algorithm is currently active on-board the instrument. In this paper, we explore the ACIS response to particle radiation through comparisons to a number of external measures of the radiation environment. We hope to better understand the efficiency of the algorithm as a function of the flux and spectrum of the particles and the time-profile of the radiation event.

  3. X-ray optics. II - A technique for high resolution spectroscopy

    NASA Technical Reports Server (NTRS)

    Cash, Webster C., Jr.

    1991-01-01

    A novel combination of optical elements and properties is combined to achieve high-spectral resolution using grazing incidence optics of modest quality. Analysis and ray tracing of examples show that using radial groove gratings at high blaze angles in the manner of an echelle spectrograph can provide high spectral resolution. This arrangement is compared to the conventional in-plane designs to show that the off-plane is superior in nearly every respect. Cross dispersion can be provided by the energy resolution of a CCD detector. Additional resolution can be squeezed from the system by strategic placement of gratings to take advantage of the azimuthal response of a Wolter X-ray optic.

  4. Synchrotron X-ray CT characterization of titanium parts fabricated by additive manufacturing. Part II. Defects.

    PubMed

    Scarlett, Nicola Vivienne Yorke; Tyson, Peter; Fraser, Darren; Mayo, Sheridan; Maksimenko, Anton

    2016-07-01

    Synchrotron X-ray tomography (SXRT) has been applied to the study of defects within three-dimensional printed titanium parts. These parts were made using the Arcam EBM(®) (electron beam melting) process which uses powdered titanium alloy, Ti64 (Ti alloy with approximately 6%Al and 4%V) as the feed and an electron beam for the sintering/welding. The experiment was conducted on the Imaging and Medical Beamline of the Australian Synchrotron. The samples represent a selection of complex shapes with a variety of internal morphologies. Inspection via SXRT has revealed a number of defects which may not otherwise have been seen. The location and nature of such defects combined with detailed knowledge of the process conditions can contribute to understanding the interplay between design and manufacturing strategy. This fundamental understanding may subsequently be incorporated into process modelling, prediction of properties and the development of robust methodologies for the production of defect-free parts. PMID:27359151

  5. Managing radiation degradation of CCDs on the Chandra X-ray Observatory II

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Aldcroft, Thomas L.; Bissell, Bradley A.; Blackwell, William C.; Cameron, Robert A.; Chappell, Jon II.; DePasquale, Joseph M.; Gage, Kenneth R.; Grant, Catherine E.; Harbison, Christine F.

    2005-01-01

    The CCDs on the Chandra X-ray Observatory are vulnerable to radiation damage from low-energy protons scattered off the telescope's mirrors onto the focal plane. Following unexpected damage incurred early in the mission, the Chandra Team developed, implemented, and maintains a radiation-protection program. This program - involving scheduled radiation safing during radiation-belt passes, intervention based upon real-time space-weather conditions and radiation-environment modeling, and on-board radiation monitoring with autonomous radiation safing - has successfully managed the radiation damage to the CCDs. Since implementing the program, the charge-transfer inefficiency (CTI) has increased at an average annual rate of only 2.9x10^-6 (2.3%) for the front- illuminated CCDs and 0.95x10^-6 (6.5%) for the back-illuminated CCDs. This paper describes the current status of Chandra radiation-management program.

  6. X-ray absorption spectroscopic evidence for the complexation of Hg(II) by reduced sulfur in soil humic substances

    SciTech Connect

    Xia, K.; Skyllberg, U.L.; Bleam, W.F.; Helmke, P.A.; Bloom, P.R.; Nater, E.A.

    1999-01-15

    Analysis of Hg(II) complexed by a soil humic acid (HA) using synchrotron-based X-ray absorption spectroscopy (XAS) revealed the importance of reduces sulfur functional groups (thiol (R-SH) and disulfide (R-SS-R)/disulfane (R-SSH)) in humic substances in the complexation of Hg(II). A two-coordinate binding environment with one oxygen atom and one sulfur atom at distances of 2.02 and 2.38 {angstrom}, respectively, was found in the first coordination shell of Hg(II) complexed by humic acid. Model calculations show that a second coordination sphere could contain one carbon atom and a second sulfur atom at 2.78 and 2.93 {angstrom}, respectively. This suggests that in addition to thiol S, disulfide/disulfane S may be involved with the complexation of Hg(II) in soil organic matter. The appearance of carbon atom in the second coordination shell suggests that one O-containing ligand such as carboxyl and phenol ligands rather than H{sub 2}O molecule is bound to the Hg(II). The involvement of oxygen ligand in addition to the reduced S ligands in the complexation of Hg(II) is due to the low density of reduced S ligands in humic substances. The XAS results from this experiment provided direct molecular level evidence for the preference of reduced S functional groups over oxygen ligands by Hg(II) in the complexation with humic substances.

  7. The extended ROSAT-ESO flux limited X-ray galaxy cluster survey (REFLEX II) II. Construction and properties of the survey

    NASA Astrophysics Data System (ADS)

    Böhringer, H.; Chon, G.; Collins, C. A.; Guzzo, L.; Nowak, N.; Bobrovskyi, S.

    2013-07-01

    Context. Galaxy clusters provide unique laboratories to study astrophysical processes on large scales and are important probes for cosmology. X-ray observations are currently the best means of detecting and characterizing galaxy clusters. Therefore X-ray surveys for galaxy clusters are one of the best ways to obtain a statistical census of the galaxy cluster population. Aims: In this paper we describe the construction of the REFLEX II galaxy cluster survey based on the southern part of the ROSAT All-Sky Survey. REFLEX II extends the REFLEX I survey by a factor of about two down to a flux limit of 1.8 × 10-12 erg s cm (0.1-2.4 keV). Methods: We describe the determination of the X-ray parameters, the process of X-ray source identification, and the construction of the survey selection function. Results: The REFLEX II cluster sample comprises currently 915 objects. A standard selection function is derived for a lower source count limit of 20 photons in addition to the flux limit. The median redshift of the sample is z = 0.102. Internal consistency checks and the comparison to several other galaxy cluster surveys imply that REFLEX II is better than 90% complete with a contamination less than 10%. Conclusions: With this publication we give a comprehensive statistical description of the REFLEX II survey and provide all the complementary information necessary for a proper modeling of the survey for astrophysical and cosmological applications. Based on observations at the European Southern Observatory La Silla, ChileFull Tables 2 and 3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/555/A30

  8. Segal crystallinity index revisited by the simulation of X-ray diffraction patterns of cotton cellulose Iβ and cellulose II.

    PubMed

    Nam, Sunghyun; French, Alfred D; Condon, Brian D; Concha, Monica

    2016-01-01

    The Segal method estimates the amorphous fraction of cellulose Iβ materials simply based on intensity at 18° 2θ in an X-ray diffraction pattern and was extended to cellulose II using 16° 2θ intensity. To address the dependency of Segal amorphous intensity on crystal size, cellulose polymorph, and the degree of polymorphic conversion, we simulated the diffraction patterns of cotton celluloses (Iβ and II) and compared the simulated amorphous fractions with the Segal values. The diffraction patterns of control and mercerized cottons, respectively, were simulated with perfect crystals of cellulose Iβ (1.54° FWHM) and cellulose II (2.30° FWHM) as well as 10% and 35% amorphous celluloses. Their Segal amorphous fractions were 15% and 31%, respectively. The higher Segal amorphous fraction for control cotton was attributed to the peak overlap. Although the amorphous fraction was set in the simulation, the peak overlap induced by the increase of FWHM further enhanced the Segal amorphous intensity of cellulose Iβ. For cellulose II, the effect of peak overlap was smaller; however the lower reflection of the amorphous cellulose scattering in its Segal amorphous location resulted in smaller Segal amorphous fractions. Despite this underestimation, the relatively good agreement of the Segal method with the simulation for mercerized cotton was attributed to the incomplete conversion to cellulose II. The (1-10) and (110) peaks of cellulose Iβ remained near the Segal amorphous location of cellulose II for blends of control and mercerized cotton fibers.

  9. X-RAY PROPERTIES OF YOUNG EARLY-TYPE GALAXIES. II. ABUNDANCE RATIO IN THE HOT INTERSTELLAR MATTER

    SciTech Connect

    Kim, Dong-Woo; Fabbiano, Giuseppina; Pipino, Antonio

    2012-05-20

    Using Chandra X-ray observations of young, post-merger elliptical galaxies, we present X-ray characteristics of age-related observational results by comparing them with typical old elliptical galaxies in terms of metal abundances in the hot interstellar matter (ISM). While the absolute element abundances may be uncertain because of unknown systematic errors and partly because of the smaller amount of hot gas in young ellipticals, the relative abundance ratios (e.g., the {alpha}-element to Fe ratio, and most importantly the Si/Fe ratio) can be relatively well constrained. In two young elliptical galaxies (NGC 720 and NGC 3923) we find that the Si to Fe abundance ratio is super-solar (at a 99% significance level), in contrast to typical old elliptical galaxies where the Si to Fe abundance ratio is close to solar. Also, the O/Mg ratio is close to solar in the two young elliptical galaxies, as opposed to the sub-solar O/Mg ratio reported in old elliptical galaxies. Both features appear to be less significant outside the effective radius (roughly 30'' for the galaxies under study), consistent with the observations that confine to the centermost regions the signatures of recent star formation in elliptical galaxies. Observed differences between young and old elliptical galaxies can be explained by the additional contribution from SNe II ejecta in the former. In young elliptical galaxies, the later star formation associated with recent mergers would have a dual effect, resulting both in galaxy scale winds-and therefore smaller observed amounts of hot ISM-because of the additional SN II heating, and in different metal abundances, because of the additional SN II yields.

  10. X-ray Absorption Spectroscopy

    SciTech Connect

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  11. ALF: a facility for x-ray lithography II--a progress report

    NASA Astrophysics Data System (ADS)

    Lesoine, L. G.; Kukkonen, Kenneth W.; Leavey, Jeffrey A.

    1992-07-01

    In our previous paper which we presented here two years ago, we described the ALF (Advanced Lithography Facility), IBM's new facility for X-ray lithography which was built as an addition to the Advanced Semiconductor Technology Center at IBM's semiconductor plant in Hopewell Jct., NY. At that time, we described the structure, its utilities, facilities and special features such as the radiation shielding, control room, clean room and vibration resistant design. The building has been completed and occupied. By the time this paper is presented the storage ring will be commissioned, the clean room occupied, and two beamlines with one stepper operational. In this paper we will review the successful completion of the facility with its associated hardware. The installation of the synchrotron will be described elsewhere. We will also discuss the first measurements of vibration, clean room cleanliness and the effectiveness of the radiation shielding. The ALF was completed on schedule and cost objectives were met. This is attributed to careful planning, close cooperation among all the parties involved from the technical team in IBM Research, the system vendor (Oxford Instruments of Oxford England) to the many contractors and subcontractors and to strong support from IBM senior management. All the planned building specifications were met and the facility has come on-line with a minimum of problems. Most important, the initial measurements show that the radiation shielding plan is sound and that with a few modifications the dose limit of 10% of background will be met. Any concerns about an electron accelerator and synchrotron in an industrial setting have been eliminated.

  12. X-ray structure of [ReCl4(mu-ox)Cu(pyim)2]: a new heterobimetallic Re(IV)Cu(II) ferrimagnetic chain.

    PubMed

    Martínez-Lillo, José; Armentano, Donatella; De Munno, Giovanni; Lloret, Francesc; Julve, Miguel; Faus, Juan

    2008-01-01

    A new heterobimetallic Re(IV)Cu(II) compound has been prepared and its crystal structure determined by single-crystal X-ray diffraction; magnetic susceptibility measurements show that this compound behaves as a ferrimagnetic chain with significant antiferromagnetic interactions between Re(IV) and Cu(II) metal ions.

  13. Palladium(II) complexes of 1,10-phenanthroline: Synthesis and X-ray crystal structure determination

    PubMed Central

    Adrian, Rafael A.; Broker, Grant A.; Tiekink, Edward R. T.

    2009-01-01

    Two palladium(II) complexes, [Pd(phen)(N≡CCH3)2][O3SCF3]2 (1) and [Pd(phen)(μ-OH)]2[O3SCF3]2·2H2O (2) (where phen= 1,10-phenanthroline), have been crystallized following the reaction of Pd(phen)Cl2 with silver triflate, Ag(O3SCF3), in acetonitrile and water, respectively. The structures of both complexes are based on a Pd(phen)2+ metal core, with two acetonitrile molecules binding in a monodentate fashion in complex 1 and two hydroxo bridges holding together two cores to form a dimer in complex 2. Additionally, both complexes present a hydrogen bonded 3-D network involving the triflate anions in 1, and water and triflate anions in 2. Both complexes have been characterized by infrared and 1H NMR spectroscopy and their crystal structures determined by X-ray crystallography. PMID:19693286

  14. Study of x-rays produced from debris-free sources with Ar, Kr and Kr/Ar mixture linear gas jets irradiated by UNR Leopard laser beam with fs and ns pulse duration

    NASA Astrophysics Data System (ADS)

    Kantsyrev, V. L.; Schultz, K. A.; Shlyaptseva, V. V.; Safronova, A. S.; Shrestha, I. K.; Petrov, G. M.; Moschella, J. J.; Petkov, E. E.; Stafford, A.; Cooper, M. C.; Weller, M. E.; Cline, W.; Wiewior, P.; Chalyy, O.

    2016-06-01

    Experiments of x-ray emission from Ar, Kr, and Ar/Kr gas jet mixture were performed at the UNR Leopard Laser Facility operated with 350 fs pulses at laser intensity of 2 × 1019 W/cm2 and 0.8 ns pulses at an intensity of 1016 W/cm2. Debris free x-ray source with supersonic linear nozzle generated clusters/monomer jet with an average density of ≥1019 cm-3 was compared to cylindrical tube subsonic nozzle, which produced only monomer jet with average density 1.5-2 times higher. The linear (elongated) cluster/gas jet provides the capability to study x-ray yield anisotropy and laser beam self-focusing with plasma channel formation that are interconnecting with efficient x-ray generation. Diagnostics include x-ray diodes, pinhole cameras and spectrometers. It was observed that the emission in the 1-9 keV spectral region was strongly anisotropic depending on the directions of laser beam polarization for sub-ps laser pulse and supersonic linear jet. The energy yield in the 1-3 keV region produced by a linear nozzle was an order of magnitude higher than from a tube nozzle. Non-LTE models and 3D molecular dynamic simulations of Ar and Kr clusters irradiated by sub-ps laser pulses have been implemented to analyze obtained data. A potential evidence of electron beam generation in jets' plasma was discussed. Note that the described debris-free gas-puff x-ray source can generate x-ray pulses in a high repetition regime. This is a great advantage compared to solid laser targets.

  15. The X-ray/SZ view of the virial region. II. Gas mass fraction

    NASA Astrophysics Data System (ADS)

    Eckert, D.; Ettori, S.; Molendi, S.; Vazza, F.; Paltani, S.

    2013-03-01

    Aims: Several recent studies used the hot gas fraction of galaxy clusters as a standard ruler to constrain dark energy, which provides competitive results compared to other techniques. This method, however, relies on the assumption that the baryon fraction in clusters agrees with the cosmic value Ωb/Ωm, and does not differ from one system to another. We test this hypothesis by measuring the gas mass fraction over the entire cluster volume in a sample of local clusters. Methods: Combining the Sunyaev-Zel'dovich thermal pressure from Planck and the X-ray gas density from ROSAT, we measured for the first time the average gas fraction (fgas) out to the virial radius and beyond in a large sample of clusters. We also obtained azimuthally-averaged measurements of the gas fraction for 18 individual systems, which we used to compute the scatter of fgas around the mean value at different radii and its dependence on the cluster's temperature. Results: The gas mass fraction increases with radius and reaches the cosmic baryon fraction close to R200. At R200, we measure fgas,200 = 0.176 ± 0.009 (0.166 ± 0.012 for the subsample of 18 clusters in common between Planck and ROSAT). We find significant differences between the baryon fraction of relaxed, cool-core (CC) systems and unrelaxed, non-cool core (NCC) clusters in the outer regions. On average, the gas fraction in NCC clusters slightly exceeds the cosmic baryon fraction, while in CC systems the gas fraction converges to the expected value when accounting for the stellar content, without any evidence for variations from one system to another. Conclusions: We find that fgas estimates in NCC systems slightly disagree with the cosmic value approaching R200. This result could be explained either by a violation of the assumption of hydrostatic equilibrium or by an inhomogeneous distribution of the gas mass. Conversely, CC clusters are found to provide reliable constraints on fgas at overdensities Δ > 200, which makes them

  16. Ni(II) and Pd(II) complexes with new N,O donor thiophene appended Schiff base ligand: Synthesis, electrochemistry, X-ray structure and DFT calculation

    NASA Astrophysics Data System (ADS)

    Kundu, Subhankar; Pramanik, Ajoy Kumar; Mondal, Apurba Sau; Mondal, Tapan Kumar

    2016-07-01

    The thiophene appended Schiff's base ligand, 1-(2-(thiophen-2-yl)ethylimino)methyl)naphthalene-2-ol (HL) with N,O donor sites has been synthesized by the condensation between 2-hydroxy-1-naphthaldehyde and thiophene-2-ethylamine. The square planar 1:2 complexes of HL having general formula [M(L)2] (M = Ni(1) and Pd(2)) with nickel(II) and palladium(II) have been synthesized and characterized by several spectroscopic techniques. The geometry has been confirmed by single crystal X-ray study for complex 1. The electronic structure and spectral properties of the complexes are interpreted by DFT and TDDFT studies.

  17. X-ray and solution structures of Cu(II) GHK and Cu(II) DAHK complexes: influence on their redox properties.

    PubMed

    Hureau, Christelle; Eury, Hélène; Guillot, Régis; Bijani, Christian; Sayen, Stéphanie; Solari, Pier-Lorenzo; Guillon, Emmanuel; Faller, Peter; Dorlet, Pierre

    2011-08-29

    The Gly-His-Lys (GHK) peptide and the Asp-Ala-His-Lys (DAHK) sequences are naturally occurring high-affinity copper(II) chelators found in the blood plasma and are hence of biological interest. A structural study of the copper complexes of these peptides was conducted in the solid state and in solution by determining their X-ray structures, and by using a large range of spectroscopies, including EPR and HYSCORE (hyperfine sub-level correlation), X-ray absorption and (1)H and (13)C NMR spectroscopy. The results indicate that the structures of [Cu(II)(DAHK)] in the solid state and in solution are similar and confirm the equatorial coordination sphere of NH(2), two amidyl N and one imidazole N. Additionally, a water molecule is bound apically to Cu(II) as revealed by the X-ray structure. As reported previously in the literature, [Cu(II)(GHK)], which exhibits a dimeric structure in the solid state, forms a monomeric complex in solution with three nitrogen ligands: NH(2), amidyl and imidazole. The fourth equatorial site is occupied by a labile oxygen atom from a carboxylate ligand in the solid state. We probe that fourth position and study ternary complexes of [Cu(II)(GHK)] with glycine or histidine. The Cu(II) exchange reaction between different DAHK peptides is very slow, in contrast to [Cu(II)(GHK)], in which the fast exchange was attributed to the presence of a [Cu(II)(GHK)(2)] complex. The redox properties of [Cu(II)(GHK)] and [Cu(II)(DAHK)] were investigated by cyclic voltammetry and by measuring the ascorbate oxidation in the presence of molecular oxygen. The measurements indicate that both Cu(II) complexes are inert under moderate redox potentials. In contrast to [Cu(II)(DAHK)], [Cu(II)(GHK)] could be reduced to Cu(I) around -0.62 V (versus AgCl/Ag) with subsequent release of the Cu ion. These complete analyses of structure and redox activity of those complexes gave new insights with biological impact and can serve as models for other more complicated Cu(II

  18. OTELO SURVEY: DEEP BVRI BROADBAND PHOTOMETRY OF THE GROTH STRIP. II. OPTICAL PROPERTIES OF X-RAY EMITTERS

    SciTech Connect

    Povic, M.; Perez GarcIa, A. M.; Bongiovanni, A.; Castaneda, H.; Lorenzo, M. Fernandez; Lara-Lopez, M. A.; Sanchez-Portal, M.; Alfaro, E.; Gallego, J.; Gonzalez-Serrano, J. I.; Gonzalez, J. J. E-mail: miguel.sanchez@sciops.esa.in

    2009-11-20

    The Groth field is one of the sky regions that will be targeted by the OSIRIS Tunable Filter Emission Line Object survey in the optical 820 nm and 920 nm atmospheric windows. In the present paper, public Chandra X-ray data with total exposure time of 200 ks are analyzed and combined with optical broadband data of the Groth field, in order to study a set of optical structural parameters of the X-ray emitters and its relation with X-ray properties. To this aim, we processed the raw, public X-ray data using the Chandra Interactive Analysis of Observations, and determined and analyzed different structural parameters, in order to produce a morphological classification of X-ray sources. We present the morphology of 340 X-ray emitters with optical counterpart detected. Objects have been classified by X-ray type using a diagnostic diagram relating X-ray-to-optical ratio (X/O) to hardness ratio. We did not find any clear correlation between X-ray and morphological types. We analyzed the angular clustering of X-ray sources with optical counterpart using two-point correlation functions. A significant positive angular clustering was obtained from a preliminary analysis of four subsamples of the X-ray sources catalog. The clustering signal of the optically extended counterparts is similar to that of strongly clustered populations like red and very red galaxies, suggesting that the environment plays an important role in active galactic nuclei phenomena. Finally, we combined optical structural parameters with other X-ray and optical properties, and we confirmed an anticorrelation between the X/O ratio and the Abraham concentration index, which might suggest that early-type galaxies have lower Eddington rates than those of late-type galaxies.

  19. 1,1'-Methylenedipyridinium tetrachloridocuprate(II) and bis[tetrachloridoaurate(III)] hybrid salts by X-ray powder diffraction.

    PubMed

    Al-Ktaifani, Mahmoud; Rukiah, Mwaffak

    2012-09-01

    In order to explore the potential propensity of the 1,1'-methylenedipyridinium dication to form organic-inorganic hybrid ionic compounds by reaction with the appropriate halide metal salt, the organic-inorganic hybrid salts 1,1'-methylenedipyridinium tetrachloridocuprate(II), (C(11)H(12)N(2))[CuCl(4)], (I), and 1,1'-methylenedipyridinium bis[tetrachloridoaurate(III)], (C(11)H(12)N(2))[AuCl(4)](2), (II), were obtained by treatment of 1,1'-methylenedipyridinium dichloride with CuCl(2) and Na[AuCl(4)], respectively. Both hybrid salts were isolated as pure compounds, fully characterized by multinuclear NMR spectroscopy and their molecular structures confirmed by powder X-ray diffraction studies. The crystal structures consist of discrete 1,1'-methylenedipyridinium dications and [CuCl(4)](2-) and [AuCl(4)](-) anions for (I) and (II), respectively. As expected, the dications form a butterfly shape; the Cu(II) centre of [CuCl(4)](2-) has a distorted tetrahedral configuration and the Au(III) centre of [AuCl(4)](-) shows a square-planar coordination. The ionic species of (I) and the dication of (II) each have twofold axial symmetry, while the two [AuCl(4)](-) anions are located on a mirror-plane site. Both crystal structures are stabilized by intermolecular C-H···Cl hydrogen bonds and also by Cl···π interactions. It is noteworthy that, while the average intermolecular centroid-centroid pyridinium ring distance in (I) is 3.643 (8) Å, giving strong evidence for noncovalent π-π ring interactions, for (II), the shortest centroid-centroid distance between pyridinium rings of 5.502 (9) Å is too long for any significant π-π ring interactions, which might be due to the bulk of the two [AuCl(4)](-) anions. PMID:22935491

  20. Interaction of ultraviolet and X-ray radiation with gamma rays produced by a jet in active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Zbyszewska, Magda

    1994-01-01

    Recent observations by the Compton Gamma-Ray Observatory give evidence for the existence of a type of blazar with strong gamma-ray emission. Data obtained by EGRET for the quasar 3C 279 show a spectrum between 100 MeV and 10 GeV. Photons of such energies should interact with the X-rays and produce positron/electron pairs. If the optical depth against pair production for the gamma rays is large (tau(gamma gamma) greater than 1), the gamma-ray spectrum should be affected. The importance of this process has been pointed out by, e.g., Maraschi, Ghisellini, & Celotti (1992). Several works (e.g., Dermer 1993; Zbyszewska 1993; Sikora, Begelman, & Rees 1993) concerning gamma-ray radiation from quasar 3C 279 have proposed a model in which the gamma rays are produced via interaction between a moving cloud of relativistic electrons and external soft photons. The presence of gamma rays in active galactic nuclei spectra gives constraints on the localization and the luminosity of the medium which produces ultraviolet/X-ray photons. We investigate what conditions should be fulfilled in the above model to avoid the absorption of the gamma rays due to pair production.

  1. X-ray studies and time-resolved photoluminescence on optically pumped antimonide-based midinfrared type-II lasers.

    PubMed

    Schwender, Carsten; Drumm, Jan Oliver; Hoffmann, Goetz; Vogelgesang, Birgit; Fouckhardt, Henning

    2004-12-01

    We report on high-resolution X-ray diffraction and time-resolved photoluminescence (TR-PL) studies of antimonide-based midinfrared (MIR) type-II laser samples. A structural characterization taking into account asymmetrical strain, layer tilting, and relaxation enables an accurate determination of the average lattice constant of the active region and the composition of the cladding layers. By designing the antimonide-to-arsenide interfaces, we achieve exact lattice matching of the active region to the substrate. Non-radiative recombination processes are investigated with time-resolved photoluminescence. The samples are also characterized under optically pumped laser operation. By an examination of the time-integrated and time-resolved amplified spontaneous emission (TR-ASE), we investigate the modal gain and gain dynamics. The variable stripe length method is combined with the TR-PL approach. Compared to the time-integrated gain spectra the spectral dependence of the maximum and minimum time-resolved gain shows a broad plateau. The full width half maximum (FWHM) of the TR-ASE pulse is 5.5 +/- 0.5 ps. Thus, short pulses in this range should be achievable upon laser operation. The active regions of the laser structures investigated here are promising subunits of type-II quantum cascade lasers.

  2. NEAR-INFRARED COUNTERPARTS TO CHANDRA X-RAY SOURCES TOWARD THE GALACTIC CENTER. II. DISCOVERY OF WOLF-RAYET STARS AND O SUPERGIANTS

    SciTech Connect

    Mauerhan, J. C.; Stolovy, S. R.; Muno, M. P.; Morris, M. R.; Cotera, A.

    2010-02-10

    We present new identifications of infrared counterparts to the population of hard X-ray sources near the Galactic center detected by the Chandra X-ray Observatory. We have spectroscopically confirmed 16 new massive stellar counterparts to the X-ray population, including nitrogen-type (WN) and carbon-type (WC) Wolf-Rayet stars, and O supergiants. These discoveries increase the total sample of massive stellar X-ray sources in the Galactic center region to 30 (possibly 31). For the majority of these sources, the X-ray photometry is consistent with thermal emission from plasma having temperatures in the range of kT = 1-8 keV or non-thermal emission having power-law indices in the range of -1 {approx}< GAMMA {approx}< 3, and X-ray luminosities in the range of L{sub X} {approx} 10{sup 32}-10{sup 34} erg s{sup -1} (0.5-8.0 keV). Several sources have exhibited X-ray variability of several factors between observations. These X-ray properties are not a ubiquitous feature of single massive stars but are typical of massive binaries, in which the high-energy emission is generated by the collision of supersonic winds, or by accretion onto a compact companion. However, without direct evidence for companions, the possibility of intrinsic hard X-ray generation from single stars cannot be completely ruled out. The spectral energy distributions of these sources exhibit significant infrared excess, attributable to free-free emission from ionized stellar winds, supplemented by hot dust emission in the case of the WC stars. With the exception of one object located near the outer regions of the Quintuplet cluster, most of the new stars appear isolated or in loose associations. Seven hydrogen-rich WN and O stars are concentrated near the Sagittarius B H II region, while other similar stars and more highly evolved hydrogen-poor WN and WC stars lie scattered within {approx}50 pc, in projection, of Sagitarrius A West. We discuss various mechanisms capable of generating the observed X-rays

  3. The Chandra Planetary Nebula Survey (ChanPlaNS). II. X-Ray Emission from Compact Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Freeman, M.; Montez, R., Jr.; Kastner, J. H.; Balick, B.; Frew, D. J.; Jones, D.; Miszalski, B.; Sahai, R.; Blackman, E.; Chu, Y.-H.; De Marco, O.; Frank, A.; Guerrero, M. A.; Lopez, J. A.; Zijlstra, A.; Bujarrabal, V.; Corradi, R. L. M.; Nordhaus, J.; Parker, Q. A.; Sandin, C.; Schönberner, D.; Soker, N.; Sokoloski, J. L.; Steffen, M.; Toalá, J. A.; Ueta, T.; Villaver, E.

    2014-10-01

    We present results from the most recent set of observations obtained as part of the Chandra X-ray observatory Planetary Nebula Survey (ChanPlaNS), the first comprehensive X-ray survey of planetary nebulae (PNe) in the solar neighborhood (i.e., within ~1.5 kpc of the Sun). The survey is designed to place constraints on the frequency of appearance and range of X-ray spectral characteristics of X-ray-emitting PN central stars and the evolutionary timescales of wind-shock-heated bubbles within PNe. ChanPlaNS began with a combined Cycle 12 and archive Chandra survey of 35 PNe. ChanPlaNS continued via a Chandra Cycle 14 Large Program which targeted all (24) remaining known compact (R neb <~ 0.4 pc), young PNe that lie within ~1.5 kpc. Results from these Cycle 14 observations include first-time X-ray detections of hot bubbles within NGC 1501, 3918, 6153, and 6369, and point sources in HbDs 1, NGC 6337, and Sp 1. The addition of the Cycle 14 results brings the overall ChanPlaNS diffuse X-ray detection rate to ~27% and the point source detection rate to ~36%. It has become clearer that diffuse X-ray emission is associated with young (lsim 5 × 103 yr), and likewise compact (R neb <~ 0.15 pc), PNe with closed structures and high central electron densities (ne >~ 1000 cm-3), and is rarely associated with PNe that show H2 emission and/or pronounced butterfly structures. Hb 5 is one such exception of a PN with a butterfly structure that hosts diffuse X-ray emission. Additionally, two of the five new diffuse X-ray detections (NGC 1501 and NGC 6369) host [WR]-type central stars, supporting the hypothesis that PNe with central stars of [WR]-type are likely to display diffuse X-ray emission.

  4. INTEGRAL SPI Observations of Cygnus X-1 in the Soft State: What about the Jet Contribution in Hard X-Rays?

    NASA Astrophysics Data System (ADS)

    Jourdain, E.; Roques, J. P.; Chauvin, M.

    2014-07-01

    During the first 7 yr of the INTEGRAL mission (2003-2009), Cyg X-1 has essentially been detected in its hard state (HS), with some incursions in intermediate HSs. This long, spectrally stable period allowed in particular the measurement of the polarization of the high-energy component that has long been observed above 200 keV in this peculiar object. This result strongly suggests that here we see the contribution of the jet, known to emit a strong synchrotron radio emission. In 2010 June, Cyg X-1 underwent a completed transition toward a soft state (SS). It gave us the unique opportunity to study in detail the corona emission in this spectral state, and to investigate in particular the behavior of the jet contribution. Indeed, during the SS, the hard X-ray emission decreases drastically, with its maximum energy shifted toward lower energy and its flux divided by a factor of ~5-10. Interestingly, the radio emission follows a similar drop, supporting the correlation between the jet emission and the hard component, even though the flux is too low to quantify the polarization characteristics. Based on observations with INTEGRAL, an ESA project with instruments and science data center funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Spain, and Switzerland), the Czech Republic and Poland with the participation of Russia and USA.

  5. INTEGRAL SPI observations of Cygnus X-1 in the soft state: What about the jet contribution in hard X-rays?

    SciTech Connect

    Jourdain, E.; Roques, J. P.; Chauvin, M.

    2014-07-01

    During the first 7 yr of the INTEGRAL mission (2003-2009), Cyg X-1 has essentially been detected in its hard state (HS), with some incursions in intermediate HSs. This long, spectrally stable period allowed in particular the measurement of the polarization of the high-energy component that has long been observed above 200 keV in this peculiar object. This result strongly suggests that here we see the contribution of the jet, known to emit a strong synchrotron radio emission. In 2010 June, Cyg X-1 underwent a completed transition toward a soft state (SS). It gave us the unique opportunity to study in detail the corona emission in this spectral state, and to investigate in particular the behavior of the jet contribution. Indeed, during the SS, the hard X-ray emission decreases drastically, with its maximum energy shifted toward lower energy and its flux divided by a factor of ∼5-10. Interestingly, the radio emission follows a similar drop, supporting the correlation between the jet emission and the hard component, even though the flux is too low to quantify the polarization characteristics.

  6. Type II Turn of Receptor-bound Salmon Calcitonin Revealed by X-ray Crystallography.

    PubMed

    Johansson, Eva; Hansen, Jakob Lerche; Hansen, Ann Maria Kruse; Shaw, Allan Christian; Becker, Peter; Schäffer, Lauge; Reedtz-Runge, Steffen

    2016-06-24

    Calcitonin is a peptide hormone consisting of 32 amino acid residues and the calcitonin receptor is a Class B G protein-coupled receptor (GPCR). The crystal structure of the human calcitonin receptor ectodomain (CTR ECD) in complex with a truncated analogue of salmon calcitonin ([BrPhe(22)]sCT(8-32)) has been determined to 2.1-Å resolution. Parallel analysis of a series of peptide ligands showed that the rank order of binding of the CTR ECD is identical to the rank order of binding of the full-length CTR, confirming the structural integrity and relevance of the isolated CTR ECD. The structure of the CTR ECD is similar to other Class B GPCRs and the ligand binding site is similar to the binding site of the homologous receptors for the calcitonin gene-related peptide (CGRP) and adrenomedulin (AM) recently published (Booe, J. M., Walker, C. S., Barwell, J., Kuteyi, G., Simms, J., Jamaluddin, M. A., Warner, M. L., Bill, R. M., Harris, P. W., Brimble, M. A., Poyner, D. R., Hay, D. L., and Pioszak, A. A. (2015) Mol. Cell 58, 1040-1052). Interestingly the receptor-bound structure of the ligand [BrPhe(22)]sCT(8-32) differs from the receptor-bound structure of the homologous ligands CGRP and AM. They all adopt an extended conformation followed by a C-terminal β turn, however, [BrPhe(22)]sCT(8-32) adopts a type II turn (Gly(28)-Thr(31)), whereas CGRP and AM adopt type I turns. Our results suggest that a type II turn is the preferred conformation of calcitonin, whereas a type I turn is the preferred conformation of peptides that require RAMPs; CGRP, AM, and amylin. In addition the structure provides a detailed molecular explanation and hypothesis regarding ligand binding properties of CTR and the amylin receptors.

  7. Accretion Disk Spectra of the Ultra-Luminous X-Ray Sources in Nearby Spiral Galaxies and Galactic Superluminal Jet Sources

    SciTech Connect

    Mizuno, T

    2003-12-11

    Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and Galactic superluminal jet sources share the common spectral characteristic that they have unusually high disk temperatures which cannot be explained in the framework of the standard optically thick accretion disk in the Schwarzschild metric. On the other hand, the standard accretion disk around the Kerr black hole might explain the observed high disk temperature, as the inner radius of the Kerr disk gets smaller and the disk temperature can be consequently higher. However, we point out that the observable Kerr disk spectra becomes significantly harder than Schwarzschild disk spectra only when the disk is highly inclined. This is because the emission from the innermost part of the accretion disk is Doppler-boosted for an edge-on Kerr disk, while hardly seen for a face-on disk. The Galactic superluminal jet sources are known to be highly inclined systems, thus their energy spectra may be explained with the standard Kerr disk with known black hole masses. For ULXs, on the other hand, the standard Kerr disk model seems implausible, since it is highly unlikely that their accretion disks are preferentially inclined, and, if edge-on Kerr disk model is applied, the black hole mass becomes unreasonably large (> 300 M{sub solar}). Instead, the slim disk (advection dominated optically thick disk) model is likely to explain the observed super-Eddington luminosities, hard energy spectra, and spectral variations of ULXs. We suggest that ULXs are accreting black holes with a few tens of solar mass, which is not unexpected from the standard stellar evolution scenario, and that their X-ray emission is from the slim disk shining at super-Eddington luminosities.

  8. Accretion Disk Spectra of the Ultra-luminous X-ray Sources in Nearby Spiral Galaxies and Galactic Superluminal Jet Sources

    NASA Technical Reports Server (NTRS)

    White, Nicholas E. (Technical Monitor); Ebisawa, Ken; Zycki, Piotr; Kubota, Aya; Mizuno, Tsunefumi; Watarai, Ken-ya

    2003-01-01

    Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and Galactic superluminal jet sources share the common spectral characteristic that they have unusually high disk temperatures which cannot be explained in the framework of the standard optically thick accretion disk in the Schwarzschild metric. On the other hand, the standard accretion disk around the Kerr black hole might explain the observed high disk temperature, as the inner radius of the Kerr disk gets smaller and the disk temperature can be consequently higher. However, we point out that the observable Kerr disk spectra becomes significantly harder than Schwarzschild disk spectra only when the disk is highly inclined. This is because the emission from the innermost part of the accretion disk is Doppler-boosted for an edge-on Kerr disk, while hardly seen for a face-on disk. The Galactic superluminal jet sources are known to be highly inclined systems, thus their energy spectra may be explained with the standard Kerr disk with known black hole masses. For ULXs, on the other hand, the standard Kerr disk model seems implausible, since it is highly unlikely that their accretion disks are preferentially inclined, and, if edge-on Kerr disk model is applied, the black hole mass becomes unreasonably large (greater than or approximately equal to 300 Solar Mass). Instead, the slim disk (advection dominated optically thick disk) model is likely to explain the observed super- Eddington luminosities, hard energy spectra, and spectral variations of ULXs. We suggest that ULXs are accreting black holes with a few tens of solar mass, which is not unexpected from the standard stellar evolution scenario, and their X-ray emission is from the slim disk shining at super-Eddington luminosities.

  9. Joint x-ray

    MedlinePlus

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  10. Chest X-Ray

    MedlinePlus

    ... by: Image/Video Gallery Your radiologist explains chest x-ray. Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

  11. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1991-01-01

    The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

  12. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1990-01-01

    The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

  13. Guanine-containing copper(II) complexes: synthesis, X-ray structures and magnetic properties.

    PubMed

    Mastropietro, Teresa F; Armentano, Donatella; Grisolia, Ettore; Zanchini, Claudia; Lloret, Francesc; Julve, Miguel; De Munno, Giovanni

    2008-01-28

    Three new compounds of formula {[Cu(gua)(H(2)O)(3)](BF(4))(SiF(6))(1/2)}(n) (1), {[Cu(gua)(H(2)O)(3)](CF(3)SO(3))(2).H(2)O}(n) (2) and [Cu(gua)(2)(H(2)O)(HCOO)]ClO(4).H(2)O.1/2HCOOH] (3) [gua = 2-amino-1H-purin-6(9H)-one] showing the unprecedented coordination of neutral guanine, have been synthesised and structurally characterized. The structures of the compounds 1 and 2 contain uniform copper(II) chains of formula [Cu(gua)(H(2)O)(3)](n)(2n+), where the copper atoms are bridged by guanine ligands coordinated via N(3) and N(7). The electroneutrality is achieved by uncoordinated tetrafluoroborate and hexafluorosilicate (1) and triflate (2). Each copper atom in 1 and 2 is five-coordinated in a distorted square pyramidal environment: two water molecules in trans positions and the N(3) and N(7a) nitrogen atoms of two guanine ligands build the basal plane whereas a water molecule fills the axial position. The values of the copper-copper separation across the bridging guanine ligand are 7.183(1) (1) and 7.123(1) A (2). is an ionic salt whose structure is made up of mononuclear [Cu(gua)(2)(H(2)O)(HCOO)](+) cations and perchlorate anions plus water and formic acid as crystallization molecules. The two guanine ligands in the cation are coordinated to the copper centre through the N(9) atom. The copper atom in 3 is four-coordinated with two monodentate guanine molecules in the trans position, a water molecule and a monodenate formate ligand building a quasi square planar surrounding. Magnetic susceptibility measurements for 1 and 2 in the temperature range 1.9-300 K show the occurrence of significant intrachain antiferromagnetic interactions between the copper(ii) ions across the guanine bridge [J = -9.6(1) (1) and -10.3(1) cm(-1) (2) with H = -J summation operator(i)S(i).S(i+1)].

  14. A radio jet from the optical and x-ray bright stellar tidal disruption flare ASASSN-14li.

    PubMed

    van Velzen, S; Anderson, G E; Stone, N C; Fraser, M; Wevers, T; Metzger, B D; Jonker, P G; van der Horst, A J; Staley, T D; Mendez, A J; Miller-Jones, J C A; Hodgkin, S T; Campbell, H C; Fender, R P

    2016-01-01

    The tidal disruption of a star by a supermassive black hole leads to a short-lived thermal flare. Despite extensive searches, radio follow-up observations of known thermal stellar tidal disruption flares (TDFs) have not yet produced a conclusive detection. We present a detection of variable radio emission from a thermal TDF, which we interpret as originating from a newly launched jet. The multiwavelength properties of the source present a natural analogy with accretion-state changes of stellar mass black holes, which suggests that all TDFs could be accompanied by a jet. In the rest frame of the TDF, our radio observations are an order of magnitude more sensitive than nearly all previous upper limits, explaining how these jets, if common, could thus far have escaped detection. PMID:26612833

  15. A radio jet from the optical and x-ray bright stellar tidal disruption flare ASASSN-14li.

    PubMed

    van Velzen, S; Anderson, G E; Stone, N C; Fraser, M; Wevers, T; Metzger, B D; Jonker, P G; van der Horst, A J; Staley, T D; Mendez, A J; Miller-Jones, J C A; Hodgkin, S T; Campbell, H C; Fender, R P

    2016-01-01

    The tidal disruption of a star by a supermassive black hole leads to a short-lived thermal flare. Despite extensive searches, radio follow-up observations of known thermal stellar tidal disruption flares (TDFs) have not yet produced a conclusive detection. We present a detection of variable radio emission from a thermal TDF, which we interpret as originating from a newly launched jet. The multiwavelength properties of the source present a natural analogy with accretion-state changes of stellar mass black holes, which suggests that all TDFs could be accompanied by a jet. In the rest frame of the TDF, our radio observations are an order of magnitude more sensitive than nearly all previous upper limits, explaining how these jets, if common, could thus far have escaped detection.

  16. A radio jet from the optical and x-ray bright stellar tidal disruption flare ASASSN-14li

    NASA Astrophysics Data System (ADS)

    van Velzen, S.; Anderson, G. E.; Stone, N. C.; Fraser, M.; Wevers, T.; Metzger, B. D.; Jonker, P. G.; van der Horst, A. J.; Staley, T. D.; Mendez, A. J.; Miller-Jones, J. C. A.; Hodgkin, S. T.; Campbell, H. C.; Fender, R. P.

    2016-01-01

    The tidal disruption of a star by a supermassive black hole leads to a short-lived thermal flare. Despite extensive searches, radio follow-up observations of known thermal stellar tidal disruption flares (TDFs) have not yet produced a conclusive detection. We present a detection of variable radio emission from a thermal TDF, which we interpret as originating from a newly launched jet. The multiwavelength properties of the source present a natural analogy with accretion-state changes of stellar mass black holes, which suggests that all TDFs could be accompanied by a jet. In the rest frame of the TDF, our radio observations are an order of magnitude more sensitive than nearly all previous upper limits, explaining how these jets, if common, could thus far have escaped detection.

  17. X-ray studies of coeval star samples. II - The Pleiades cluster as observed with the Einstein Observatory

    NASA Technical Reports Server (NTRS)

    Micela, G.; Sciortino, S.; Vaiana, G. S.; Harnden, F. R., Jr.; Rosner, R.

    1990-01-01

    Coronal X-ray emission of the Pleiades stars is investigated, and maximum likelihood, integral X-ray luminosity functions are computed for Pleiades members in selected color-index ranges. A detailed search is conducted for long-term variability in the X-ray emission of those stars observed more than once. An overall comparison of the survey results with those of previous surveys confirms the ubiquity of X-ray emission in the Pleiades cluster stars and its higher rate of emission with respect to older stars. It is found that the X-ray emission from dA and early dF stars cannot be proven to be dissimilar to that of Hyades and field stars of the same spectral type. The Pleiades cluster members show a real rise of the X-ray luminosity from dA stars to early dF stars. X-ray emission for the young, solarlike Pleiades stars is about two orders of magnitude more intense than for the nearby solarlike stars.

  18. Serial time-resolved crystallography of photosystem II using a femtosecond X-ray laser

    PubMed Central

    Kupitz, Christopher; Basu, Shibom; Grotjohann, Ingo; Fromme, Raimund; Zatsepin, Nadia A.; Rendek, Kimberly N.; Hunter, Mark S.; Shoeman, Robert L.; White, Thomas A.; Wang, Dingjie; James, Daniel; Yang, Jay-How; Cobb, Danielle E.; Reeder, Brenda; Sierra, Raymond G.; Liu, Haiguang; Barty, Anton; Aquila, Andrew L.; Deponte, Daniel; Kirian, Richard A.; Bari, Sadia; Bergkamp, Jesse J.; Beyerlein, Kenneth R.; Bogan, Michael J.; Caleman, Carl; Chao, Tzu-Chiao; Conrad, Chelsie E.; Davis, Katherine M.; Fleckenstein, Holger; Galli, Lorenzo; Hau-Riege, Stefan P.; Kassemeyer, Stephan; Laksmono, Hartawan; Liang, Mengning; Lomb, Lukas; Marchesini, Stefano; Martin, Andrew V.; Messerschmidt, Marc; Milathianaki, Despina; Nass, Karol; Ros, Alexandra; Roy-Chowdhury, Shatabdi; Schmidt, Kevin; Seibert, Marvin; Steinbrener, Jan; Stellato, Francesco; Yan, Lifen; Yoon, Chunhong; Moore, Thomas A.; Moore, Ana L.; Pushkar, Yulia; Williams, Garth J.; Boutet, Sébastien; Doak, R. Bruce; Weierstall, Uwe; Frank, Matthias; Chapman, Henry N.; Spence, John C. H.; Fromme, Petra

    2015-01-01

    Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which maintains the Earth’s oxygenic atmosphere1. In this process, the oxygen-evolving complex (OEC) of PSII cycles through five states, S0 to S4, in which four electrons are sequentially extracted from the OEC in four light-driven charge-separation events. Here we describe time resolved experiments on PSII nano/microcrystals from Thermosynechococcus elongatus performed with the recently developed2 technique of serial femtosecond crystallography. Structures have been determined from PSII in the dark S1 state and after double laser excitation (putative S3 state) at 5 and 5.5 Å resolution, respectively. The results provide evidence that PSII undergoes significant conformational changes at the electron acceptor side and at the Mn4CaO5 core of the OEC. These include an elongation of the metal cluster, accompanied by changes in the protein environment, which could allow for binding of the second substrate water molecule between the more distant protruding Mn (referred to as the ‘dangler’ Mn) and the Mn3CaOx cubane in the S2 to S3 transition, as predicted by spectroscopic and computational studies3,4. This work shows the great potential for time-resolved serial femtosecond crystallography for investigation of catalytic processes in biomolecules. PMID:25043005

  19. Reaction Mechanism of Glutamate Carboxypeptidase II Revealed by Mutagenesis, X-ray Crystallography, and Computational Methods

    SciTech Connect

    Klusak, Vojtech; Barinka, Cyril; Plechanovova, Anna; Mlcochova, Petra; Konvalinka, Jan; Rulisek, Lubomir; Lubkowski, Jacek

    2009-05-29

    Glutamate carboxypeptidase II (GCPII, EC 3.4.17.21) is a zinc-dependent exopeptidase and an important therapeutic target for neurodegeneration and prostate cancer. The hydrolysis of N-acetyl-l-aspartyl-l-glutamate (N-Ac-Asp-Glu), the natural dipeptidic substrate of the GCPII, is intimately involved in cellular signaling within the mammalian nervous system, but the exact mechanism of this reaction has not yet been determined. To investigate peptide hydrolysis by GCPII in detail, we constructed a mutant of human GCPII [GCPII(E424A)], in which Glu424, a putative proton shuttle residue, is substituted with alanine. Kinetic analysis of GCPII(E424A) using N-Ac-Asp-Glu as substrate revealed a complete loss of catalytic activity, suggesting the direct involvement of Glu424 in peptide hydrolysis. Additionally, we determined the crystal structure of GCPII(E424A) in complex with N-Ac-Asp-Glu at 1.70 {angstrom} resolution. The presence of the intact substrate in the GCPII(E424A) binding cavity substantiates our kinetic data and allows a detailed analysis of GCPII/N-Ac-Asp-Glu interactions. The experimental data are complemented by the combined quantum mechanics/molecular mechanics calculations (QM/MM) which enabled us to characterize the transition states, including the associated reaction barriers, and provided detailed information concerning the GCPII reaction mechanism. The best estimate of the reaction barrier was calculated to be {Delta}G {approx} 22({+-}5) kcal{center_dot}mol{sup -1}, which is in a good agreement with the experimentally observed reaction rate constant (k{sub cat} {approx} 1 s{sup -1}). Combined together, our results provide a detailed and consistent picture of the reaction mechanism of this highly interesting enzyme at the atomic level.

  20. Serial time-resolved crystallography of photosystem II using a femtosecond X-ray laser.

    PubMed

    Kupitz, Christopher; Basu, Shibom; Grotjohann, Ingo; Fromme, Raimund; Zatsepin, Nadia A; Rendek, Kimberly N; Hunter, Mark S; Shoeman, Robert L; White, Thomas A; Wang, Dingjie; James, Daniel; Yang, Jay-How; Cobb, Danielle E; Reeder, Brenda; Sierra, Raymond G; Liu, Haiguang; Barty, Anton; Aquila, Andrew L; Deponte, Daniel; Kirian, Richard A; Bari, Sadia; Bergkamp, Jesse J; Beyerlein, Kenneth R; Bogan, Michael J; Caleman, Carl; Chao, Tzu-Chiao; Conrad, Chelsie E; Davis, Katherine M; Fleckenstein, Holger; Galli, Lorenzo; Hau-Riege, Stefan P; Kassemeyer, Stephan; Laksmono, Hartawan; Liang, Mengning; Lomb, Lukas; Marchesini, Stefano; Martin, Andrew V; Messerschmidt, Marc; Milathianaki, Despina; Nass, Karol; Ros, Alexandra; Roy-Chowdhury, Shatabdi; Schmidt, Kevin; Seibert, Marvin; Steinbrener, Jan; Stellato, Francesco; Yan, Lifen; Yoon, Chunhong; Moore, Thomas A; Moore, Ana L; Pushkar, Yulia; Williams, Garth J; Boutet, Sébastien; Doak, R Bruce; Weierstall, Uwe; Frank, Matthias; Chapman, Henry N; Spence, John C H; Fromme, Petra

    2014-09-11

    Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which maintains the Earth's oxygenic atmosphere. In this process, the oxygen-evolving complex (OEC) of PSII cycles through five states, S0 to S4, in which four electrons are sequentially extracted from the OEC in four light-driven charge-separation events. Here we describe time resolved experiments on PSII nano/microcrystals from Thermosynechococcus elongatus performed with the recently developed technique of serial femtosecond crystallography. Structures have been determined from PSII in the dark S1 state and after double laser excitation (putative S3 state) at 5 and 5.5 Å resolution, respectively. The results provide evidence that PSII undergoes significant conformational changes at the electron acceptor side and at the Mn4CaO5 core of the OEC. These include an elongation of the metal cluster, accompanied by changes in the protein environment, which could allow for binding of the second substrate water molecule between the more distant protruding Mn (referred to as the 'dangler' Mn) and the Mn3CaOx cubane in the S2 to S3 transition, as predicted by spectroscopic and computational studies. This work shows the great potential for time-resolved serial femtosecond crystallography for investigation of catalytic processes in biomolecules.

  1. Serial time-resolved crystallography of photosystem II using a femtosecond X-ray laser.

    PubMed

    Kupitz, Christopher; Basu, Shibom; Grotjohann, Ingo; Fromme, Raimund; Zatsepin, Nadia A; Rendek, Kimberly N; Hunter, Mark S; Shoeman, Robert L; White, Thomas A; Wang, Dingjie; James, Daniel; Yang, Jay-How; Cobb, Danielle E; Reeder, Brenda; Sierra, Raymond G; Liu, Haiguang; Barty, Anton; Aquila, Andrew L; Deponte, Daniel; Kirian, Richard A; Bari, Sadia; Bergkamp, Jesse J; Beyerlein, Kenneth R; Bogan, Michael J; Caleman, Carl; Chao, Tzu-Chiao; Conrad, Chelsie E; Davis, Katherine M; Fleckenstein, Holger; Galli, Lorenzo; Hau-Riege, Stefan P; Kassemeyer, Stephan; Laksmono, Hartawan; Liang, Mengning; Lomb, Lukas; Marchesini, Stefano; Martin, Andrew V; Messerschmidt, Marc; Milathianaki, Despina; Nass, Karol; Ros, Alexandra; Roy-Chowdhury, Shatabdi; Schmidt, Kevin; Seibert, Marvin; Steinbrener, Jan; Stellato, Francesco; Yan, Lifen; Yoon, Chunhong; Moore, Thomas A; Moore, Ana L; Pushkar, Yulia; Williams, Garth J; Boutet, Sébastien; Doak, R Bruce; Weierstall, Uwe; Frank, Matthias; Chapman, Henry N; Spence, John C H; Fromme, Petra

    2014-09-11

    Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which maintains the Earth's oxygenic atmosphere. In this process, the oxygen-evolving complex (OEC) of PSII cycles through five states, S0 to S4, in which four electrons are sequentially extracted from the OEC in four light-driven charge-separation events. Here we describe time resolved experiments on PSII nano/microcrystals from Thermosynechococcus elongatus performed with the recently developed technique of serial femtosecond crystallography. Structures have been determined from PSII in the dark S1 state and after double laser excitation (putative S3 state) at 5 and 5.5 Å resolution, respectively. The results provide evidence that PSII undergoes significant conformational changes at the electron acceptor side and at the Mn4CaO5 core of the OEC. These include an elongation of the metal cluster, accompanied by changes in the protein environment, which could allow for binding of the second substrate water molecule between the more distant protruding Mn (referred to as the 'dangler' Mn) and the Mn3CaOx cubane in the S2 to S3 transition, as predicted by spectroscopic and computational studies. This work shows the great potential for time-resolved serial femtosecond crystallography for investigation of catalytic processes in biomolecules. PMID:25043005

  2. Cytotoxic trans-platinum(II) complex with 3-hydroxymethylpyridine: Synthesis, X-ray structure and biological activity evaluation.

    PubMed

    Grabner, Sabina; Modec, Barbara; Bukovec, Nataša; Bukovec, Peter; Čemažar, Maja; Kranjc, Simona; Serša, Gregor; Sčančar, Janez

    2016-08-01

    To assess the potential cytostatic properties of Pt(II) complexes with 3-hydroxymethylpyridine (3-hmpy) as the only carrier ligand, novel cis-[PtCl2(3-hmpy)2] (1) and trans-[PtCl2(3-hmpy)2] (2) have been prepared. Elemental analysis, FTIR spectroscopy, multinuclear NMR spectroscopy and X-ray crystallography were used to determine their structures. Based on the results obtained with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and clonogenic assay on T24 human bladder carcinoma cells (T24), the most potent compound 2 was further tested for cytotoxicity in human ovarian carcinoma cell lines - cisplatin sensitive (IGROV 1) and its resistant subclone (IGROV 1/RDDP). The cytotoxicity of compound 2 in IGROV 1/RDDP is comparable to cisplatin. Furthermore, compound 2 induced severe conformational changes in plasmid DNA, which resulted in a delayed onset of apoptosis in T24 cells, and higher amounts of Pt in tumours and serum compared to cisplatin. In addition, in vivo antitumour effectiveness was comparable to that of cisplatin with a smaller reduction of animals' body weight, thus demonstrating that it is a promising transplatin analogue which deserves further studies. PMID:27189143

  3. Structural Properties of Human CaMKII Ca2+ /Calmodulin-Dependent Protein Kinase II using X-ray Crystallography

    NASA Astrophysics Data System (ADS)

    Cao, Yumeng Melody; McSpadden, Ethan; Kuriyan, John; Department of Molecular; Cell Biology; Department of Chemistry Team

    To this day, human memory storage remains a mystery as we can at most describe the process vaguely on a cellular level. Switch-like properties of Calcium/Calmodulin-Dependent Protein Kinase II make it a leading candidate in understanding the molecular basis of human memory. The protein crystal was placed in the beam of a synchrotron source and the x-ray crystallography data was collected as reflections on a diffraction pattern that undergo Fourier transform to obtain the electron density. We observed two drastic differences from our solved structure at 2.75Å to a similar construct of the mouse CaMKII association domain. Firstly, our structure is a 6-fold symmetric dodecamer, whereas the previously published construct was a 7-fold symmetric tetradecamer. This suggests the association domain of human CaMKII is a dynamic structure that is triggered subunit exchange process. Secondly, in our structure the N-terminal tag is docked as an additional beta-strand on an uncapped beta-sheet present in each association domain protomer. This is concrete evidence of the involvement of the polypeptide docking site in the molecular mechanism underlining subunit exchange. In the future, we would like to selectively inhibit the exchange process while not disrupting the other functionalities of CaMKII.

  4. Synthesis, X-ray structure, spectroscopic properties and DFT studies of some dithiocarbazate complexes of nickel(II)

    NASA Astrophysics Data System (ADS)

    Takjoo, Reza; Centore, Roberto

    2013-01-01

    Two nickel(II) complexes with formulae NiL2 (1) and NiL'Im (2) (HL = allyl 2-benzylidene-hydrazinecarbodithioate, H2L' = allyl 2-(2-hydroxybenzylidene)hydrazinecarbodithioate, Im = Imidazole) have been synthesized and characterized by elemental analysis, molar conductivities, FT-IR, 1H NMR and UV/Vis spectroscopy. The crystal structure of the complexes has been determined by single crystal X-ray diffractometry. Both L and L' ligands are coordinated to the metal in the thiolate form. In 1, the square planar coordination of the metal is achieved by coordination of two bidentate ligand units acting through azomethine nitrogen and the thiolato sulfur donor atoms. The complex 2 has a square-planar geometry with the tridentate ligand coordinated to the metal through salicylate oxygen, azomethine nitrogen and the thiolato sulfur atoms, while the fourth coordination position is occupied by one N atom of imidazole. Also natural bond orbitals (NBOs), frontier molecular orbitals (FMOs) and Mulliken charge computational studies on complexes carried out in the ground state with the DFT and theory at B3LYP/6-31G(d,p) level of theory.

  5. The First Detection of [O IV] from an Ultraluminous X-ray Source with Spitzer. II. Evidence for High Luminosity in Holmberg II ULX

    NASA Technical Reports Server (NTRS)

    Berghea, C. T.; Dudik, R. P.; Weaver, K. A.; Kallman, T. R.

    2009-01-01

    This is the second of two papers examining Spitzer Infrared Spectrograph (IRS) observations of the ultraluminous X-ray source (ULX) in Holmberg II. Here we perform detailed photoionization modeling of they infrared lines. Our analysis suggests that the luminosity and morphology of the [O IV] 25.89 micron emission line is consistent with photoionization by the soft X-ray and far ultraviolet (FUV) radiation from the accretion disk of the binary system and inconsistent with narrow beaming. We show that the emission nebula is matter-bounded both in the line of sight direction and to the east, and probably radiation-bounded to the west. A bolometric luminosity in excess of 1040 erg per second would be needed to produce the measured [O IV] flux. We use modeling and previously published studies to conclude that shacks likely contribute very little, if at all, to the high excitation line fluxes observed in the Holmberg II ULX. Additionally, we find that the spectral type of the companion star has a surprisingly strong effect on they predicted strength of the [O IV] emission. This finding could explain the origin of [O IV] hi some starburst systems containing black hole binaries.

  6. Synthesis, X-ray crystal structure and spectroscopy of a Werner-type host Co(II) complex, trans-bisisothiocyanatotetrakis( trans-4-styrylpyridine)cobalt(II)

    NASA Astrophysics Data System (ADS)

    Karunakaran, C.; Thomas, K. R. J.; Shunmugasundaram, A.; Murugesan, R.

    2000-05-01

    Single crystals of the title Co(II) complex, [Co(stpy) 4(NCS) 2] [stpy= trans-4-styrylpyridine] are prepared and characterized by elemental analysis, IR, and UV-visible spectroscopy and X-ray crystal structure determination. The complex crystallizes in the orthorhombic space group Pna2 1 with unit-cell parameters, a=32.058(3), b=15.362(5), c=9.818(5) Å, and Z=4. The structure consists of discrete monomeric units of [Co(stpy) 4(NCS) 2]. The equatorial positions of the Co(II) polyhedron are occupied by nitrogen atoms of the four stpy ligands and the axial positions are occupied by the nitrogen atoms of the two thiocyanate ions. The unit cell packing reveals interpenetration of styryl groups owing to conformational flexibility of phenyl and pyridyl rings in stpy ligands. Thus, it leads to efficient packing of the crystal lattice leaving no space available for guest inclusion. IR spectra reveal nitrogen coordination from stpy and terminal -NCS coordination of the thiocyanate group. The optical reflectance bands 475, 540 (shoulder) and 1022 nm suggest octahedral geometry in accordance with the X-ray data. However, the optical spectrum of acetonitrile solution shows an intense band at 615 nm and a weak shoulder at 570 nm suggesting participation of the solvent molecules in the coordination sphere. These bands indicate the presence of both tetrahedral and octahedral species in solution.

  7. Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

    NASA Technical Reports Server (NTRS)

    Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B.; Allen, Maxwell J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C., Jr.

    1991-01-01

    The Multispectral Solar Telescope Array is a rocket-borne observatory which encompasses seven compact soft X-ray/EUV, multilayer-coated, and two compact far-UV, interference film-coated, Cassegrain and Ritchey-Chretien telescopes. Extensive measurements are presented on the efficiency and spectral bandpass of the X-ray/EUV telescopes. Attention is given to systematic errors and measurement errors.

  8. Novel bimetallic thiocyanate-bridged Cu(II)-Hg(II) compounds—synthesis, X-Ray studies and magnetic properties

    NASA Astrophysics Data System (ADS)

    Machura, B.; Świtlicka, A.; Zwoliński, P.; Mroziński, J.; Kalińska, B.; Kruszynski, R.

    2013-01-01

    Seven novel heterobimetallic Cu/Hg polymers based on thiocyanate bridges have been synthesised and characterised by means of IR, EPR, magnetic measurements and single crystal X-Ray. Three of them, [Cu(pzH)4Hg(SCN)4]n (1) [Cu(indH)4Hg(SCN)4]n (2) and [Cu(ampy)2Hg(SCN)4]n (3), have one-dimensional coordination structure. Two compounds [Cu(pzH)2Hg(SCN)4]n (4) and [Cu(abzimH)Hg(SCN)4]n (5) form two-dimensional nets, whereas the complexes [Cu(pyCN)2Hg(SCN)4]n (6) and [Cu(pyCH(OH)(OMe))2Hg(SCN)4]n (7) are three-dimensional coordination polymers. The chains of 1 are connected by the intermolecular N-H•••N hydrogen bonds to the three dimensional net. In 2 the N-H•••S hydrogen bonds link the polymeric chains to the two dimensional layer extending along crystallographic (0 0 1) plane. The polymeric chains of compound 3 are joined by the intermolecular N-H•••N and N-H•••S hydrogen bonds to the three dimensional net. The polymeric layers of 4 are connected by the intermolecular N-H•••N hydrogen bonds to the three dimensional net.

  9. Cu(II)-Zn(II) Cross-Modulation in Amyloid-Beta Peptide Binding: an X-ray Absorption Spectroscopy Study

    PubMed Central

    De Santis, Emiliano; Minicozzi, Velia; Proux, Olivier; Rossi, Giancarlo; Silva, K. Ishara; Lawless, Matthew J.; Stellato, Francesco; Saxena, Sunil; Morante, Silvia

    2015-01-01

    In this work we analyze at a structural level the mechanism by which Cu(II) and Zn(II) ions compete for binding to the Aβ peptides that is involved in the etiology of Alzheimer’s disease. We collected X-ray Absorption Spectroscopy data on samples containing Aβ with Cu and Zn at different concentration ratios. We show that the order in which metals are added to the peptide solution matters and that, when Zn is added first, it prevents Cu from binding. On the contrary, when Cu is added first, it does not (completely) prevent Zn binding to Aβ peptides. Our analysis suggests that Cu and Zn ions are coordinated to different numbers of histidine residues depending on the [ion]:[peptide] concentration ratio. PMID:26646533

  10. Study of the Local Structure of II-Vi Ternary Alloys by Extended X-Ray Absorption Fine Structure

    NASA Astrophysics Data System (ADS)

    Pong, Way-Faung

    Bondlengths, Debye-Waller factors, and site occupancy in the diluted magnetic semiconductors Zn_ {rm 1 - x}Mn_{ rm x}Se and Hg_{ rm 1 - x}Mn_{rm x}Te, and the narrow-gap semiconductor Hg _{rm 1 - x}Cd _{rm x}Te have been measured using extended x-ray absorption fine structure (EXAFS). The nearest-neighbor bond lengths in all of these alloys are found to be constant as a function of alloy composition within the experimental uncertainty of 0.01A. Because the average cation-cation distance changes with Mn composition, these results necessarily imply distortion of the tetrahedral bond angles. In the case of Zn_{rm 1 - x}Mn_{rm x} Se, the anion sublattice is shown to suffer the largest distortion, but the cation sublattice also exhibits some relaxation. The repercussions of these results are discussed, in terms of the amount of cation and anion sublattice distortion at low temperature and its connection to the superexchange mechanism occurring between the Mn ^{+2} ions and mediated by the intervening anion in Zn_{rm 1 - x}Mn_{rm x} Se. From the NN bond length relaxation results shown in this study and those reported elsewhere for the III -V-based and II-VI-based ternary compounds and DMS alloys, it appears that substitution of Mn^{+2 } ions into II-VI-based compounds causes greater local distortion, in general, than otherwise observed when group II cations are substituted for one another. We believe that the tetrahedral bond weakening in DMS is due to MN 3d-orbital (t_2) and anion p-orbital hybridization in DMS, leaving fewer p-orbitals available for tetrahedral bonding. This leads to the weakening of the bond force constants alpha, beta, as well as the bond becoming more ionic as Mn^{+2} is substituted into the II-VI-based compounds. Finally, the experimentally extended electron energy loss fine structure (EXELFS) technique, with modulations in the differential inelastic electron scattering cross -section above an absorption core edge, has been used in recent years to

  11. Chest x-ray

    MedlinePlus

    Chest radiography; Serial chest x-ray; X-ray - chest ... You stand in front of the x-ray machine. You will be told to hold your breath when the x-ray is taken. Two images are usually taken. You will ...

  12. A Fast, Versatile Nanoprobe for Complex Materials: The Sub-micron Resolution X-ray Spectroscopy Beamline at NSLS-II (491st Brookhaven Lecture)

    SciTech Connect

    Thieme, Juergen

    2014-02-06

    Time is money and for scientists who need to collect data at research facilities like Brookhaven Lab’s National Synchrotron Light Source (NSLS), “beamtime” can be a precious commodity. While scanning a complex material with a specific technique and standard equipment today would take days to complete, researchers preparing to use brighter x-rays and the new sub-micron-resolution x-ray spectroscopy (SRX) beamline at the National Synchrotron Light Source II (NSLS-II) could scan the same sample in greater detail with just a few hours of beamtime. Talk about savings and new opportunities for researchers! Users will rely on these tools for locating trace elements in contaminated soils, developing processes for nanoparticles to deliver medical treatments, and much more. Dr. Thieme explains benefits for next-generation research with spectroscopy and more intense x-rays at NSLS-II. He discusses the instrumentation, features, and uses for the new SRX beamline, highlighting its speed, adjustability, and versatility for probing samples ranging in size from millimeters down to the nanoscale. He will talk about complementary beamlines being developed for additional capabilities at NSLS-II as well.

  13. Analysis of the radiation-damage-free X-ray structure of photosystem II in light of EXAFS and QM/MM data.

    PubMed

    Askerka, Mikhail; Vinyard, David J; Wang, Jimin; Brudvig, Gary W; Batista, Victor S

    2015-03-10

    A recent femtosecond X-ray diffraction study produced the first high-resolution structural model of the oxygen-evolving complex of photosystem II that is free of radiation-induced manganese reduction (Protein Data Bank entries 4UB6 and 4UB8 ). We find, however, that the model does not match extended X-ray absorption fine structure and QM/MM data for the S1 state. This is attributed to uncertainty about the positions of oxygen atoms that remain partially unresolved, even at 1.95 Å resolution, next to the heavy manganese centers. In addition, the photosystem II crystals may contain significant amounts of the S0 state, because of extensive dark adaptation prior to data collection.

  14. Positions of galactic X-ray sources with l/II/ between -20 deg and +6 deg

    NASA Technical Reports Server (NTRS)

    Jernigan, J. G.; Bradt, H. V.; Doxsey, R. E.; Dower, R. G.; Mcclintock, J. E.; Apparao, K. M. V.

    1978-01-01

    The precise positions of nine X-ray sources in the vicinity of the galactic center are reported. The data were obtained as part of the comprehensive survey of the galactic plane performed with the rotating modulation collimator detectors on the SAS-3 X-ray observatory. The sources include the binary X-ray source 4U 1700-37 which has a well established optical counterpart that lies 7 sec from the reported position. The other sources GX 349+2, 4U 1702-42, 4U 1705-44, MX 1716-31, A 1742-294, 4U 1755-33, GX 5-1, and 2S 1803-245 lack established counterparts in other wavelengths. The obtained position for GX 5-1 adds confidence to the radio counterpart proposed by Braes et al. (1972). The reported position for 4U 1755-33 excludes the optical counterpart proposed by Jones et al. (1974).

  15. The extended ROSAT-ESO Flux-Limited X-ray Galaxy Cluster Survey (REFLEX II) - III. Construction of the first flux-limited supercluster sample

    NASA Astrophysics Data System (ADS)

    Chon, Gayoung; Böhringer, Hans; Nowak, Nina

    2013-03-01

    We present the first supercluster catalogue constructed with the extended ROSAT-ESO Flux-Limited X-ray (REFLEX II) Galaxy Cluster survey data, which comprises 919 X-ray selected galaxy clusters with a flux limit of 1.8 × 10-12 erg s-1 cm-2. Based on this cluster catalogue we construct a supercluster catalogue using a friends-of-friends algorithm with a linking length depending on the (local) cluster density, which thus varies with redshift. The resulting catalogue comprises 164 superclusters at redshift z ≤ 0.4. The choice of the linking length in the friends-of-friends method modifies the properties of the superclusters. We study the properties of different catalogues such as the distributions of the redshift, extent and multiplicity by varying the choice of parameters. In addition to the supercluster catalogue for the entire REFLEX II sample, we compile a large volume-limited cluster sample from REFLEX II with the redshift and luminosity constraints of z ≤ 0.1 and LX ≥ 5 × 1043 erg s-1. With this catalogue we construct a volume-limited sample of superclusters. This sample is built with a homogeneous linking length, and hence selects effectively the same type of superclusters. By increasing the luminosity cut we can build a hierarchical tree structure of the volume-limited samples, where systems at the top of the tree are only formed via the most luminous clusters. This allows us to test if the same superclusters are found when only the most luminous clusters are visible, comparable to the situation at higher redshift in the REFLEX II sample. We find that the selection of superclusters is very robust, independent of the luminosity cut, and the contamination of spurious superclusters among cluster pairs is expected to be small. Numerical simulations and observations of the substructure of clusters suggest that regions of high cluster number density provide an astrophysically different environment for galaxy clusters, where the mass function and X-ray

  16. Thoracic spine x-ray

    MedlinePlus

    Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

  17. The First Detection of [O IV] from an Ultraluminous X-ray Source with Spitzer. I. Observational Results for Holmberg II ULX

    NASA Technical Reports Server (NTRS)

    Berghea, C. T.; Dudik, R. P.; Weaver, K. A.; Kallman, T. R.

    2009-01-01

    We presen the first Spitzer Infrared Spectrograph (IRS) observations of the [O IV] 25.89 um emission line detected from the ultraluminous X-ray source (ULX) in Holmberg II. This line is a well established signature of high excitation usually associated with AGN. Its detection suggests that the ULX has a strong impact on the surrounding gas. A Spitzer high resolution spectral map shows that the [O IV] is coincident with the X-ray position of the ULX. The ratios of the [O IV] to lower ionization lines are similar to those observed in AGN, suggesting that a strong UV and X-ray source is responsible for the, photoionization. The best XMM-Newton data is used to model the X-ray band which is then extrapolated into the UV. We perform infrared and ultraviolet photometry, and use its previously published optical and radio data to construct the full SED for the ULX and its companion. The preferred model to describe the SED includes an accretion disk which dominates the soft X-rays but contributes little at UV and optical wavelengths. The optical counterpart is consistent with a B supergiant as previously suggested in other studies. The bolometric luminosity of the ULX suggests the presence of an intermediate-mass black hole with mass >85 M for sub-Eddington accretion or, alternatively, a stellar-mass black hole that is accreting at super-Eddington rates. In a follow-up second paper we perform detailed photoionization modeling of the infrared lines in order to constrain the bolometric luminosity of the ULX.

  18. The Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

    NASA Technical Reports Server (NTRS)

    Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B. C., Jr.; Allen, Max J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C.

    1992-01-01

    We have developed seven compact soft X-ray/EUV (XUV) multilayer coated and two compact FUV interference film coated Cassegrain and Ritchey-Chretien telescopes for a rocket borne observatory, the Multi-Spectral Solar Telescope Array. We report here on extensive measurements of the efficiency and spectral bandpass of the XUV telescopes carried out at the Stanford Synchrotron Radiation Laboratory.

  19. A novel approach for x-ray scattering experiments in magnetic fields utilizing trapped flux in type-II superconductors

    SciTech Connect

    Das, R.K.; Islan, Z.; Ruff, J.P.C.; Sawh, R.P.; Weinstein, R.; Canfield, Paul C.; Kim, J.-W.; Lang, J.C.

    2012-06-08

    We introduce a novel approach to x-ray scattering studies in applied magnetic fields by exploiting vortices in superconductors. This method is based on trapping magnetic flux in a small disk-shaped superconductor (known as a trapped field magnet, TFM) with a single-crystal sample mounted on or at close proximity to its surface. This opens an unrestricted optical access to the sample and allows magnetic fields to be applied precisely along the x-ray momentum transfer, facilitating polarization-sensitive experiments that have been impractical or impossible to perform to date. The TFMs used in our study remain stable and provide practically uniform magnetic fields for days, which are sufficient for comprehensive x-ray diffraction experiments, specifically x-ray resonance exchange scattering (XRES) to study field-induced phenomena at a modern synchrotron source. The TFM instrument has been used in a “proof-of-principle” XRES study of a meta-magnetic phase in a rare-earth compound, TbNi2Ge2, in order to demonstrate its potential.

  20. A new sample of X-ray selected narrow emission-line galaxies. II. Looking for True Seyfert 2

    NASA Astrophysics Data System (ADS)

    Pons, E.; Watson, M. G.

    2016-10-01

    A sample of X-ray and optically selected narrow emission-line galaxies (769 sources) from the 3XMM catalogue cross-correlated with SDSS (DR9) catalogue has been studied. Narrow-emission line active galactic nuclei (AGN; type-2) have been selected on the basis of their emission line ratios and/or X-ray luminosity. We have looked for X-ray unobscured type-2 AGN. As X-ray spectra were not available for our whole sample, we have checked the reliability of using the X-ray hardness ratio (HR) as a probe of the level of obscuration and we found a very good agreement with full spectral fitting results, with only 2% of the sources with apparently unobscured HR turning out to have an obscured spectrum. Despite the fact that type-2 AGN are supposed to be absorbed based on the Unified Model, about 60% of them show no sign or very low level of X-ray obscuration. After subtraction of contaminants to the sample, that is Narrow-Line Seyfert 1 and Compton-thick AGN, the fraction of unobscured Sy2 drops to 47%. For these sources, we were able to rule out dust reddening and variability for most of them as an explanation of the absence of optical broad emission-lines. The main explanations remaining are the dilution of weak/very broad emission-lines by the host galaxy and the intrinsic absence of the broad-line region (BLR) due to low accretion rates (i.e. True Sy2). However, the number of True Sy2 strongly depends on the method used to verify the intrinsic lack of broad lines. Indeed using the optical continuum luminosity to predict the BLR properties gives a much larger fraction of True Sy2 (about 90% of the unobscured Sy2 sample) than the use of the X-ray 2 keV luminosity (about 20%). Nevertheless the number of AGN we securely detected as True Sy2 is at least three times larger that the previously confirmed number of True Sy2.

  1. Structure and orientation of the Mn4Ca cluster in plant photosystem II membranes studied by polarized range-extended x-ray absorption spectroscopy.

    PubMed

    Pushkar, Yulia; Yano, Junko; Glatzel, Pieter; Messinger, Johannes; Lewis, Azul; Sauer, Kenneth; Bergmann, Uwe; Yachandra, Vittal

    2007-03-01

    X-ray absorption spectroscopy has provided important insights into the structure and function of the Mn(4)Ca cluster in the oxygen-evolving complex of Photosystem II (PS II). The range of manganese extended x-ray absorption fine structure data collected from PS II until now has been, however, limited by the presence of iron in PS II. Using a crystal spectrometer with high energy resolution to detect solely the manganese Kalpha fluorescence, we are able to extend the extended x-ray absorption fine structure range beyond the onset of the iron absorption edge. This results in improvement in resolution of the manganese-backscatterer distances in PS II from 0.14 to 0.09A(.) The high resolution data obtained from oriented spinach PS II membranes in the S(1) state show that there are three di-mu-oxo-bridged manganese-manganese distances of approximately 2.7 and approximately 2.8A in a 2:1 ratio and that these three manganese-manganese vectors are aligned at an average orientation of approximately 60 degrees relative to the membrane normal. Furthermore, we are able to observe the separation of the Fourier peaks corresponding to the approximately 3.2A manganese-manganese and the approximately 3.4A manganese-calcium interactions in oriented PS II samples and determine their orientation relative to the membrane normal. The average of the manganese-calcium vectors at approximately 3.4A is aligned along the membrane normal, while the approximately 3.2A manganese-manganese vector is oriented near the membrane plane. A comparison of this structural information with the proposed Mn(4)Ca cluster models based on spectroscopic and diffraction data provides input for refining and selecting among these models.

  2. The First Detection of [O IV] from an Ultraluminous X-ray Source with Spitzer: Evidence of High Unbeamed Luminosity in Holmberg II ULX

    NASA Technical Reports Server (NTRS)

    Berghea, C. T.; Dudik, R. P.; Weaver, K. A.; Kallman, T. R.

    2008-01-01

    We present the first Spitzer Infrared Spectrograph (IRS) observations of the [O IV] 25.89 micron emission line detected from the ultraluminous X-ray source (ULX) in Holmberg II. This line is a well established signature of high excitation, usually associated with AGN. Its detection suggests that the ULX has a strong impact on the surrounding gas. A Spitzer high resolution spectral map shows that the [O IV] is coincident with the X-ray position of the Holmberg II ULX. We find that the luminosity and the morphology of the line emission is consistent with photoionization by the soft X-ray and far ultraviolet (FUV) radiation from the accretion disk of the binary system and inconsistent with narrow beaming. We show that the emission nebula is radiation bounded both in the line of sight direction and to the west, and probably matter bounded to the east. Evidence for a massive black hole (BH) in this ULX is mounting. Detailed photoionization models favor an intermediate mass black hole of at least 85 Solar Mass as the ionization source for the [OIV] emission. We find that the spectral type of the companion star strongly affects the expected strength of the [O IV] emission. This finding could explain the origin of [O IV] in some starburst galaxies containing black hole binaries.

  3. Dental x-rays

    MedlinePlus

    X-ray - teeth; Radiograph - dental; Bitewings; Periapical film; Panoramic film; Digital image ... dentist's office. There are many types of dental x-rays. Some of them are: Bitewing. Shows the crown ...

  4. X-ray (image)

    MedlinePlus

    X-rays are a form of ionizing radiation that can penetrate the body to form an image on ... will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other ...

  5. X-Ray Lasers

    ERIC Educational Resources Information Center

    Chapline, George; Wood, Lowell

    1975-01-01

    Outlines the prospects of generating coherent x rays using high-power lasers and indentifies problem areas in their development. Indicates possible applications for coherent x rays in the fields of chemistry, biology, and crystallography. (GS)

  6. X Ray Topography

    ERIC Educational Resources Information Center

    Balchin, A. A.

    1974-01-01

    Discusses some aspects in X-ray topography, including formation of dislocations, characteristics of stacking faults, x-ray contrast in defect inspection, Berg-Barrett technique, and Lang traversing crystal and Borrmann's methods. (CC)

  7. Photodiode-Based X-Ray Beam-Position Monitor With High Spatial-Resolution for the NSLS-II Beamlines

    SciTech Connect

    Yoon, P.S.; Siddons, D. P.

    2009-05-25

    We developed a photodiode-based monochromatic X-ray beam-position monitor (X-BPM) with high spatial resolution for the project beamlines of the NSLS-II. A ring array of 32 Si PIN-junction photodiodes were designed for use as a position sensor, and a low-noise HERMES4 ASIC chip was integrated into the electronic readout system. A series of precision measurements to characterize electrically the Si-photodiode sensor and the ASIC chip demonstrated that the inherent noise is sufficiently below tolerance levels. Following up modeling of detector's performance, including geometrical optimization using a Gaussian beam, we fabricated and assembled a first prototype. In this paper, we describe the development of this new state-of-the-art X-ray BPM along the beamline, in particular, downstream from the monochromator.

  8. Dinuclear methoxido-bridged Cu(II) compounds with 7-azaindole as a ligand: Synthesis, characterization and X-ray structures

    NASA Astrophysics Data System (ADS)

    van Albada, Gerard A.; van der Horst, Maarten G.; Mutikainen, Ilpo; Turpeinen, Urho; Reedijk, Jan

    2011-05-01

    Three novel methoxido-bridged dinuclear Cu(II) compounds with the ligand 7-azaindole (abbreviated as Haza), i.e. [Cu 2(Haza) 4(CH 3O) 2(ClO 4) 2] ( 1), [Cu 2(Haza) 4(CH 3O) 2(CF 3SO 3) 2] ( 2) and [Cu 2(Haza) 4(CH 3O) 2(NO 3) 2] ( 3) have been synthesized and fully characterized by spectroscopy, EPR and X-ray structure analysis. The Cu(II) ions show a tetragonally distorted octahedral geometry, with a CuN 2O 2 chromophore in the basal plane.

  9. X-Ray Imaging

    MedlinePlus

    ... Brain Surgery Imaging Clinical Trials Basics Patient Information X-Ray Imaging Print This Page X-ray imaging is perhaps the most familiar type of imaging. Images produced by X-rays are due to the different absorption rates of ...

  10. X-Rays

    MedlinePlus

    X-rays are a type of radiation called electromagnetic waves. X-ray imaging creates pictures of the inside of your ... different amounts of radiation. Calcium in bones absorbs x-rays the most, so bones look white. Fat and ...

  11. Hand x-ray

    MedlinePlus

    X-ray - hand ... A hand x-ray is taken in a hospital radiology department or your health care provider's office by an ... technician. You will be asked to place your hand on the x-ray table, and keep it ...

  12. Crystal and molecular structure of norspermine copper(II) sulphate trihydrate studied by X-ray and IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Perkowska, A.; Małuszyńska, H.

    1999-09-01

    The title compound [Cu(C 9H 18N 4)]SO 4·3H 2O [A] was studied by X-ray and IR spectroscopy. It crystallises as monoclinic, in the space group P2 1/c with a=9.719(2), b=13.470(3), c=12.865(3) Å, β=95.36(3) and Z=4. The copper atom is five-coordinated with four nitrogen atoms and one oxygen atom from the sulphate group, forming a tricyclic chelated norspermine complex consisting of three six-membered rings, one of which is disordered. The amine groups from norspermine are hydrogen bonded to the sulphate anions. The water molecules of crystallisation form infinite (H 2O) n chains and through the sulphate anions link the norspermine complexes in the three-dimensional hydrogen bond network. The FT-IR spectra before and after dehydration of [A] confirm the X-ray results.

  13. X-ray sources in regions of star formation. II - The pre-main-sequence G star HDE 283572

    NASA Technical Reports Server (NTRS)

    Walter, F. M.; Brown, A.; Linsky, J. L.; Rydgren, A. E.; Vrba, F.

    1987-01-01

    This paper reports the detection of HDE 283572, a ninth-magnitude G star 8 arcmin south of RY Tau, as a bright X-ray source. The observations reveal this object to be a fairly massive (about 2 solar masses) pre-main-sequence star associated with the Taurus-Auriga star formation complex. It exhibits few of the characteristics of the classical T Tauri stars and is a good example of a 'naked' T Tauri star. The star is a mid-G subgiant, of about three solar radii and rotates with a period of 1.5 d. The coronal and chromospheric surface fluxes are similar to those of the most active late type stars (excluding T Tauri stars). The X-ray and UV lines most likely arise in different atmospheric structures. Radiative losses are some 1000 times the quiet solar value and compare favorably with those of T Tauri stars.

  14. Preliminary X-ray crystallographic studies of BthTX-II, a myotoxic Asp49-phospholipase A{sub 2} with low catalytic activity from Bothrops jararacussu venom

    SciTech Connect

    Corrêa, L. C.; Marchi-Salvador, D. P.; Cintra, A. C. O.; Soares, A. M.

    2006-08-01

    A myotoxic Asp49-PLA{sub 2} with low catalytic activity from B. jararacussu (BthTX-II) was crystallized in the monoclinic crystal system; a complete X-ray diffraction data set was collected and a molecular-replacement solution was obtained. The oligomeric structure of BthTX-II resembles those of the Asp49-PLA{sub 2} PrTX-III and all bothropic Lys49-PLA{sub 2}s. For the first time, a complete X-ray diffraction data set has been collected from a myotoxic Asp49-phospholipase A{sub 2} (Asp49-PLA{sub 2}) with low catalytic activity (BthTX-II from Bothrops jararacussu venom) and a molecular-replacement solution has been obtained with a dimer in the asymmetric unit. The quaternary structure of BthTX-II resembles the myotoxin Asp49-PLA{sub 2} PrTX-III (piratoxin III from B. pirajai venom) and all non-catalytic and myotoxic dimeric Lys49-PLA{sub 2}s. In contrast, the oligomeric structure of BthTX-II is different from the highly catalytic and non-myotoxic BthA-I (acidic PLA{sub 2} from B. jararacussu). Thus, comparison between these structures should add insight into the catalytic and myotoxic activities of bothropic PLA{sub 2}s.

  15. X-ray emission from the Wolf-Rayet bubble NGC 6888 - II. XMM-Newton EPIC observations

    NASA Astrophysics Data System (ADS)

    Toalá, J. A.; Guerrero, M. A.; Chu, Y.-H.; Arthur, S. J.; Tafoya, D.; Gruendl, R. A.

    2016-03-01

    We present deep XMM-Newton European Photon Imaging Camera observations of the Wolf-Rayet (WR) bubble NGC 6888 around the star WR 136. The complete X-ray mapping of the nebula confirms the distribution of the hot gas in three maxima spatially associated with the caps and north-west blowout hinted at by previous Chandra observations. The global X-ray emission is well described by a two-temperature optically thin plasma model (T1 = 1.4 × 106 K, T2 = 8.2 × 106 K) with a luminosity of LX = 7.8 × 1033 erg s-1 in the 0.3-1.5 keV energy range. The rms electron density of the X-ray-emitting gas is estimated to be ne = 0.4 cm-3. The high-quality observations presented here reveal spectral variations within different regions in NGC 6888, which allowed us for the first time to detect temperature and/or nitrogen abundance inhomogeneities in the hot gas inside a WR nebula. One possible explanation for such spectral variations is that the mixing of material from the outer nebula into the hot bubble is less efficient around the caps than in other nebular regions.

  16. X-ray-based measurement of composition during electron beam melting of AISI 316 stainless steel: Part II. Evaporative processes and simulation

    NASA Astrophysics Data System (ADS)

    Ritchie, M.; Lee, P. D.; Mitchell, A.; Cockcroft, S. L.; Wang, T.

    2003-03-01

    An energy dispersive X-ray (EDX) detector mounted on a laboratory scale electron beam furnace (30 kW) was employed to assess the potential use of X-rays as a means of on-line composition monitoring during electron beam (E B) melting of alloys. The design and construction of the collimation and protection systems used for the EDX are described in Part I. In Part II, a mathematical simulation of the heat, mass, and momentum transfer was performed for comparison to the EDX and vapor deposition results. The predicted flow patterns and evaporation rates are used to explain the differences between the two experimental methods. For the EDX spectra measured, the X-rays generated were from the center of the hearth where fluid flow rising from the bulk of the pool is sufficient to maintain the bulk composition despite the high evaporative flux from the surface. The flow moves radially outward from the center of the pool, with the volatile species being depleted. The vapor deposition technique measures the entire region, giving an average surface composition, and it therefore differs from the EDX results, which gave a near bulk composition. This combined study using in-situ EDX measurements and numerical simulations both provided an insight into the phenomena controlling the evaporation in an EB-heated system and demonstrated the viability of using EDX to measure the bulk composition during EB melting processes.

  17. Polarized X-Ray Absorption Spectroscopy of Single-Crystal Mn(V) Complexes Relevant to the Oxygen-Evolving Complex of Photosystem II

    SciTech Connect

    Yano, J.K.; Robblee, J.; Pushkar, Y.; Marcus, M.A.; Bendix, J.; Workman, J.M.; Collins, T.J.; Solomon, E.I.; George, S.D.; Yachandra, V.K.; /LBL, Berkeley /Copenhagen U. /Stanford U., Chem. Dept. /SLAC, SSRL

    2007-10-16

    High-valent Mn-oxo species have been suggested to have a catalytically important role in the water splitting reaction which occurs in the Photosystem II membrane protein. In this study, five- and six-coordinate mononuclear Mn(V) compounds were investigated by polarized X-ray absorption spectroscopy in order to understand the electronic structure and spectroscopic characteristics of high-valent Mn species. Single crystals of the Mn(V)-nitrido and Mn(V)-oxo compounds were aligned along selected molecular vectors with respect to the X-ray polarization vector using X-ray diffraction. The local electronic structure of the metal site was then studied by measuring the polarization dependence of X-ray absorption near-edge spectroscopy (XANES) pre-edge spectra (1s to 3d transition) and comparing with the results of density functional theory (DFT) calculations. The Mn(V)-nitrido compound, in which the manganese is coordinated in a tetragonally distorted octahedral environment, showed a single dominant pre-edge peak along the MnN axis that can be assigned to a strong 3dz2-4pz mixing mechanism. In the square pyramidal Mn(V)-oxo system, on the other hand, an additional peak was observed at 1 eV below the main pre-edge peak. This component was interpreted as a 1s to 3dxz,yz transition with 4px,y mixing, due to the displacement of the Mn atom out of the equatorial plane. The XANES results have been correlated to DFT calculations, and the spectra have been simulated using a TD (time-dependent)-DFT approach. The relevance of these results to understanding the mechanism of the photosynthetic water oxidation is discussed.

  18. In Situ X-ray Absorption Spectroscopy Studies of Kinetic Interaction between Platinum(II) Ions and UiO-66 Series Metal–Organic Frameworks

    SciTech Connect

    Xiao, Chaoxian; Goh, Tian Wei; Brashler, Kyle; Pei, Yuchen; Guo, Zhiyong; Huang, Wenyu

    2014-09-07

    The interaction of guest Pt(II) ions with UiO-66–X (X = NH2, H, NO2, OMe, F) series metal–organic frameworks (MOFs) in aqueous solution was investigated using in situ X-ray absorption spectroscopy. All of these MOFs were found to be able to coordinate with Pt(II) ions. The Pt(II) ions in UiO-66–X MOFs generally coordinate with 1.6–2.4 Cl and 1.4–2.4 N or O atoms. We also studied the time evolution of the coordination structure and found that Pt(II) maintained a coordination number of 4 throughout the whole process. Furthermore, the kinetic parameters of the interaction of Pt(II) ions with UiO-66–X series MOFs (X = NH2, H, NO2, OMe, F) were determined by combinational linear fitting of extended X-ray absorption fine structure (EXAFS) spectra of the samples. The Pt(II) adsorption rate constants were found to be 0.063 h–1 for UiO-66–NH2 and 0.011–0.017 h–1 for other UiO-66–X (X = H, NO2, OMe, F) MOFs, which means that Pt(II) adsorption in UiO-66–NH2 is 4–6 times faster than that in other UiO-66 series MOFs. FTIR studies suggested that the carboxyl groups could be the major host ligands binding with Pt(II) ions in UiO-66 series MOFs, except for UiO-66–NH2, in which amino groups coordinate with Pt(II) ions.

  19. Galaxy formation with local photoionization feedback - II. Effect of X-ray emission from binaries and hot gas

    NASA Astrophysics Data System (ADS)

    Kannan, R.; Vogelsberger, M.; Stinson, G. S.; Hennawi, J. F.; Marinacci, F.; Springel, V.; Macciò, A. V.

    2016-05-01

    We study how X-rays from stellar binary systems and the hot intracluster medium (ICM) affect the radiative cooling rates of gas in galaxies. Our study uses a novel implementation of gas cooling in the moving-mesh hydrodynamics code AREPO. X-rays from stellar binaries do not affect cooling at all as their emission spectrum is too hard to effectively couple with galactic gas. In contrast, X-rays from the ICM couple well with gas in the temperature range 104-106 K. Idealized simulations show that the hot halo radiation field has minimal impact on the dynamics of cooling flows in clusters because of the high virial temperature ( ≳ 107 K), making the interaction between the gas and incident photons very ineffective. Satellite galaxies in cluster environments, on the other hand, experience a high radiation flux due to the emission from the host halo. Low-mass satellites ( ≲ 1012 M⊙) in particular have virial temperatures that are exactly in the regime where the effect of the radiation field is maximal. Idealized simulations of satellite galaxies including only the effect of host halo radiation (no ram pressure stripping or tidal effects) fields show a drastic reduction in the amount of cool gas formed (˜40 per cent) on a short time-scale of about 0.5 Gyr. A galaxy merger simulation including all the other environmental quenching mechanisms, shows about 20 per cent reduction in the stellar mass of the satellite and about ˜30 per cent reduction in star formation rate after 1 Gyr due to the host hot halo radiation field. These results indicate that the hot halo radiation fields potentially play an important role in quenching galaxies in cluster environments.

  20. Constraints on energy release in solar flares from RHESSI and GOES X-ray observations. II. Energetics and energy partition

    NASA Astrophysics Data System (ADS)

    Warmuth, A.; Mann, G.

    2016-04-01

    Aims: We derive constraints on energy release, transport and conversion processes in solar flares based on a detailed characterization of the physical parameters of both the thermal plasma and the accelerated nonthermal electrons based on X-ray observations. In particular, we address the questions of whether the energy required to heat the thermal plasma can be supplied by nonthermal particles, and how the energetics derived from X-rays compare to the total bolometric radiated energy. Methods: Time series of spectral fits and images for 24 flares ranging from GOES class C3.4 to X17.2 were obtained using RHESSI hard X-ray observations. This has been supplemented by GOES soft X-ray fluxes. In our companion Paper I, we have used this data set to obtain the basic physical parameters for the thermal plasma (using the isothermal approximation) and the injected energetic electrons (assuming the thick-target model). Here, we used this data set to derive the flare energetics, including thermal energy, radiative and conductive energy loss, gravitational and flow energy of the plasma, and kinetic energy of the injected electrons. We studied how the thermal energies compare to the energy in nonthermal electrons, and how the various energetics and energy partition depend on flare importance. Results: All flare energetics show a good to excellent correlation with the peak GOES flux. The gravitational energy of the evaporated plasma and the kinetic energy of plasma flows can be neglected in the discussion of flare energetics. The radiative energy losses are comparable to the maximum thermal energy, while the conductive losses are considerably higher than the maximum thermal energy, especially in weaker flares. The total heating requirement of the hot plasma amounts to ≈50% of the total bolometric energy loss, with the conductive losses as a major contribution. The nonthermal energy input by energetic electrons is not sufficient to account for the total heating requirements of

  1. 2,6-Bis(2,6-diethylphenyliminomethyl)pyridine coordination compounds with cobalt(II), nickel(II), copper(II), and zinc(II): synthesis, spectroscopic characterization, X-ray study and in vitro cytotoxicity.

    PubMed

    Martinez-Bulit, Pablo; Garza-Ortíz, Ariadna; Mijangos, Edgar; Barrón-Sosa, Lidia; Sánchez-Bartéz, Francisco; Gracia-Mora, Isabel; Flores-Parra, Angelina; Contreras, Rosalinda; Reedijk, Jan; Barba-Behrens, Norah

    2015-01-01

    Coordination compounds with cobalt(II), nickel(II), copper(II) and zinc(II) and the ligand 2,6-bis(2,6-diethylphenyliminomethyl)pyridine (L) were synthesized and fully characterized by IR and UV-Vis-NIR spectroscopy, elemental analysis, magnetic susceptibility and X-ray diffraction for two representative cases. These novel compounds were designed to study their activity as anti-proliferative drugs against different human cancer cell lines. The tridentate ligand forms heptacoordinated compounds from nitrate metallic salts, where the nitrate acts in a chelating form to complete the seven coordination positions. In vitro cell growth inhibition was measured for Co(II), Cu(II) and Zn(II) complexes, as well as for the free ligand. Upon coordination, the IC50 value of the transition-metal compounds is improved compared to the free ligand. The copper(II) and zinc(II) compounds are the most promising candidates for further in vitro and in vivo studies. The activity against colon and prostate cell lines merits further research, in views of the limited therapeutic options for such cancer types.

  2. Panoramic Dental X-Ray

    MedlinePlus

    ... X-ray? What is Panoramic X-ray? Panoramic radiography , also called panoramic x-ray , is a two- ... Exams Dental Cone Beam CT X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety About this Site ...

  3. X-Rays and Protostars in the Trifid Nebula

    NASA Astrophysics Data System (ADS)

    Rho, Jeonghee; Corcoran, Michael F.; Chu, You-Hua; Reach, William T.

    2001-11-01

    The Trifid Nebula is a young H II region, recently rediscovered as a ``pre-Orion'' star-forming region, containing protostars undergoing violent mass ejections visible in optical jets as seen in images from the Infrared Space Observatory and the Hubble Space Telescope. We report the first X-ray observations of the Trifid Nebula using ROSAT and ASCA. The ROSAT image shows a dozen X-ray sources, with the brightest X-ray source being the O7 star, HD 164492, which provides most of the ionization in the nebula. We also identify 85 T Tauri star and young, massive star candidates from near-infrared colors using the JHKs color-color diagram from the Two-Micron All-Sky Survey (2MASS). Ten X-ray sources have counterpart near-infrared sources. The 2MASS stars and X-ray sources suggest there are potentially numerous protostars in the young H II region of the Trifid. ASCA moderate-resolution spectroscopy of the brightest source shows hard emission up to 10 keV with a clearly detected Fe K line. The best model fit is a two-temperature (T=1.2×106 K and 39×106 K) thermal model with additional warm absorbing media. The hotter component has an unusually high temperature for either an O star or an H II region; a typical Galactic H II region could not be the primary source for such hot temperature plasma and the Fe XXV line emission. We suggest that the hotter component originates in either the interaction of the wind with another object (a companion star or a dense region of the nebula) or from flares from deeply embedded young stars.

  4. X-ray fluorescence analysis of Mexican varieties of dried chili peppers II: Commercial and home-grown specimens

    NASA Astrophysics Data System (ADS)

    Romero-Dávila, E.; Miranda, J.; Pineda, J. C.

    2015-07-01

    Elemental analyses of samples of Mexican varieties of dried chili peppers were carried out using X-ray Fluorescence (XRF). Several specimens of Capsicum annuum L., Capsicum chinense, and Capsicum pubescens were analyzed and the results compared to previous studies of elemental contents in other varieties of Capsicum annuum (ancho, morita, chilpotle, guajillo, pasilla, and árbol). The first set of samples was bought packaged in markets. In the present work, the study focuses on home-grown samples of the árbol and chilpotle varieties, commercial habanero (Capsicum chinense), as well as commercial and home-grown specimens of manzano (Capsicum pubescencs). Samples were freeze dried and pelletized. XRF analyses were carried out using a spectrometer based on an Rh X-ray tube, using a Si-PIN detector. The system detection calibration was performed through the analysis of the NIST certified reference materials 1547 (peach leaves) and 1574 (tomato leaves), while accuracy was checked with the reference material 1571 (orchard leaves). Elemental contents of all elements in the new set of samples were similar to those of the first group. Nevertheless, it was found that commercial samples contain high amounts of Br, while home-grown varieties do not.

  5. Substrate specificity of pyrimidine nucleoside phosphorylases of NP-II family probed by X-ray crystallography and molecular modeling

    NASA Astrophysics Data System (ADS)

    Balaev, V. V.; Lashkov, A. A.; Prokofev, I. I.; Gabdulkhakov, A. G.; Seregina, T. A.; Mironov, A. S.; Betzel, C.; Mikhailov, A. M.

    2016-09-01

    Pyrimidine nucleoside phosphorylases, which are widely used in the biotechnological production of nucleosides, have different substrate specificity for pyrimidine nucleosides. An interesting feature of these enzymes is that the three-dimensional structure of thymidine-specific nucleoside phosphorylase is similar to the structure of nonspecific pyrimidine nucleoside phosphorylase. The three-dimensional structures of thymidine phosphorylase from Salmonella typhimurium and nonspecific pyrimidine nucleoside phosphorylase from Bacillus subtilis in complexes with a sulfate anion were determined for the first time by X-ray crystallography. An analysis of the structural differences between these enzymes demonstrated that Lys108, which is involved in the phosphate binding in pyrimidine nucleoside phosphorylase, corresponds to Met111 in thymidine phosphorylases. This difference results in a decrease in the charge on one of the hydroxyl oxygens of the phosphate anion in thymidine phosphorylase and facilitates the catalysis through SN2 nucleophilic substitution. Based on the results of X-ray crystallography, the virtual screening was performed for identifying a potent inhibitor (anticancer agent) of nonspecific pyrimidine nucleoside phosphorylase, which does not bind to thymidine phosphorylase. The molecular dynamics simulation revealed the stable binding of the discovered compound—2-pyrimidin-2-yl-1H-imidazole-4-carboxylic acid—to the active site of pyrimidine nucleoside phosphorylase.

  6. A CFH12k lensing survey of X-ray luminous galaxy clusters. II. Weak lensing analysis and global correlations

    NASA Astrophysics Data System (ADS)

    Bardeau, S.; Soucail, G.; Kneib, J.-P.; Czoske, O.; Ebeling, H.; Hudelot, P.; Smail, I.; Smith, G. P.

    2007-08-01

    Aims:We present a wide-field multi-color survey of a homogeneous sample of eleven clusters of galaxies for which we measure total masses and mass distributions from weak lensing. This sample, spanning a small range in both X-ray luminosity and redshift, is ideally suited to determining the normalisation of scaling relations between X-ray properties of clusters and their masses (the M-TX and the M-LX relations) and also estimating the scatter in these relations at a fixed luminosity. Methods: The eleven clusters in our sample are all X-ray luminous and span a narrow redshift range at z = 0.21 ± 0.04. The weak lensing analysis of the sample is based on ground-based wide-field imaging obtained with the CFH12k camera on CFHT. We use the methodology developed and applied previously on the massive cluster Abell 1689. A Bayesian method, implemented in the Im2shape software, is used to fit the shape parameters of the faint background galaxies and to correct for PSF smearing. A multi-color selection of the background galaxies is applied to retrieve the weak lensing signal, resulting in a background density of sources of ~10 galaxies per square arc minute. With the present data, shear profiles are measured in all clusters out to at least 2 Mpc (more than 15´ from the center) with high confidence. The radial shear profiles are fitted with different parametric mass profiles and the virial mass M200 is estimated for each cluster and then compared to other physical properties. Results: Scaling relations between mass and optical luminosity indicate an increase of the M/L ratio with luminosity (M/L ∝ L0.8) and a LX-M200 relation scaling as LX ∝ M2000.83 ± 0.11 while the normalization of the M200 ∝ TX3/2 relation is close to the one expected from hydrodynamical simulations of cluster formation as well as previous X-ray analyses. We suggest that the dispersion in the M200-TX and M200-LX relations reflects the different merging and dynamical histories for clusters of similar

  7. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  8. Evidence of CuI/CuII Redox Process by X-ray Absorption and EPR Spectroscopy: Direct Synthesis of Dihydrofurans from b-Ketocarbonyl Derivatives and Olefins

    SciTech Connect

    Yi, Hong; Liao, Zhixiong; Zhang, Guanghui; Zhang, Guoting; Fan, Chao; Zhang, Xu; Bunel, Emilio E.; Pao, Chih-Wen; Lee, Jyh-Fu; Lei, Aiwen

    2015-01-01

    Abstract: The CuI/CuII and CuI/CuIII catalytic cycles have been subject to intense debate in the field of copper-catalyzed oxidative coupling reactions. A mechanistic study on the CuI/CuII redox process, by X-ray absorption (XAS) and electron paramagnetic resonance (EPR) spectroscopies, has elucidated the reduction mechanism of CuII to CuI by 1,3-diketone and detailed investigation revealed that the halide ion is important for the reduction process. The oxidative nature of the thereby-formed CuI has also been studied by XAS and EPR spectroscopy. This mechanistic information is applicable to the copper-catalyzed oxidative cyclization of b-ketocarbonyl derivatives to dihydrofurans. This protocol provides an ideal route to highly substituted dihydrofuran rings from easily available 1,3-dicarbonyls and olefins. Copper

  9. Synthesis, characterization and single crystal x-ray analysis of a complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Andotra, Savit; Kaur, Mandeep; Gupta, Vivek K.; Kant, Rajni; Pandey, Sushil K.

    2016-09-01

    Complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine [{(2,4- (CH3)2C6H3O)2PS2}2Fe{NC5H4(C2H5)-4}2] is synthesized and characterized by elemental analysis, magnetic moment, IR spectroscopy and single crystal X-ray analysis. Complex crystallizes in the monoclinic sp. gr. P21/ n, Z = 2. Crystal structure consists of mononuclear units with Fe(II) ion chelated by four S atoms of the two diphenyldithiophosphate ligands in bidentate manner. N atoms from two 4-ethylpyridine ligands are axially coordinated to the Fe(II) atom leading to an octahedral geometry.

  10. Element-specific characterization of transient electronic structure of solvated Fe(II) complexes with time-resolved soft X-ray absorption spectroscopy.

    PubMed

    Hong, Kiryong; Cho, Hana; Schoenlein, Robert W; Kim, Tae Kyu; Huse, Nils

    2015-11-17

    Polypyridyl transition-metal complexes are an intriguing class of compounds due to the relatively facile chemical designs and variations in ligand-field strengths that allow for spin-state changes and hence electronic configurations in response to external perturbations such as pressure and light. Light-activated spin-conversion complexes have possible applications in a variety of molecular-based devices, and ultrafast excited-state evolution in these complexes is of fundamental interest for understanding of the origins of spin-state conversion in metal complexes. Knowledge of the interplay of structure and valence charge distributions is important to understand which degrees of freedom drive spin-conversion and which respond in a favorable (or unfavorable) manner. To track the response of the constituent components, various types of time-resolved X-ray probe methods have been utilized for a broad range of chemical and biological systems relevant to catalysis, solar energy conversions, and functional molecular devices. In particular, transient soft X-ray spectroscopy of solvated molecules can offer complementary information on the detailed electronic structures and valence charge distributions of photoinduced intermediate species: First-row transition-metal L-edges consist of 2p-3d transitions, which directly probe the unoccupied valence density of states and feature lifetime broadening in the range of 100 meV, making them sensitive spectral probes of metal-ligand interactions. In this Account, we present some of our recent progress in employing picosecond and femtosecond soft X-ray pulses from synchrotron sources to investigate element specific valence charge distributions and spin-state evolutions in Fe(II) polypyridyl complexes via core-level transitions. Our results on transient L-edge spectroscopy of Fe(II) complexes clearly show that the reduction in σ-donation is compensated by significant attenuation of π-backbonding upon spin-crossover. This underscores

  11. The Megasecond Chandra X-Ray Visionary Project Observation of NGC 3115. II. Properties of Point Sources

    NASA Astrophysics Data System (ADS)

    Lin, Dacheng; Irwin, Jimmy A.; Wong, Ka-Wah; Jennings, Zachary G.; Homan, Jeroen; Romanowsky, Aaron J.; Strader, Jay; Sivakoff, Gregory R.; Brodie, Jean P.; Remillard, Ronald A.

    2015-07-01

    We carried out an in-depth study of low-mass X-ray binaries (LMXBs) detected in the nearby lenticular galaxy NGC 3115 using the Megasecond Chandra X-ray Visionary Project observation (total exposure time 1.1 Ms). In total we found 136 candidate LMXBs in the field and 49 in globular clusters (GCs) above 2σ detection, with 0.3-8 keV luminosity LX ˜ 1036-1039 erg s-1. Other than 13 transient candidates, the sources overall have less long-term variability at higher luminosity, at least at {L}{{X}}≳ 2× {10}37 erg s-1. In order to identify the nature and spectral state of our sources, we compared their collective spectral properties based on single-component models (a simple power law or a multicolor disk) with the spectral evolution seen in representative Galactic LMXBs. We found that in the LX versus photon index {{{Γ }}}{PL} and LX versus disk temperature kTMCD plots, most of our sources fall on a narrow track in which the spectral shape hardens with increasing luminosity below {L}{{X}}˜ 7× {10}37 erg s-1, but is relatively constant ({{{Γ }}}{PL}˜ 1.5 or {{kT}}{MCD}˜ 1.5 keV) above this luminosity, which is similar to the spectral evolution of Galactic neutron star (NS) LMXBs in the soft state in the Chandra bandpass. Therefore, we identified the track as the NS LMXB soft-state track and suggested sources with {L}{{X}}≲ 7× {10}37 erg s-1 as atolls in the soft state and those with {L}{{X}}≳ 7× {10}37 erg s-1 as Z sources. Ten other sources (five are transients) displayed significantly softer spectra and are probably black hole X-ray binaries in the thermal state. One of them (persistent) is in a metal-poor GC.

  12. The Megasecond Chandra X-Ray Visionary Project Observation of NGC 3115. II. Properties of Point Sources

    NASA Astrophysics Data System (ADS)

    Lin, Dacheng; Irwin, Jimmy A.; Wong, Ka-Wah; Jennings, Zachary G.; Homan, Jeroen; Romanowsky, Aaron J.; Strader, Jay; Sivakoff, Gregory R.; Brodie, Jean P.; Remillard, Ronald A.

    2015-07-01

    We carried out an in-depth study of low-mass X-ray binaries (LMXBs) detected in the nearby lenticular galaxy NGC 3115 using the Megasecond Chandra X-ray Visionary Project observation (total exposure time 1.1 Ms). In total we found 136 candidate LMXBs in the field and 49 in globular clusters (GCs) above 2σ detection, with 0.3–8 keV luminosity LX ∼ 1036–1039 erg s‑1. Other than 13 transient candidates, the sources overall have less long-term variability at higher luminosity, at least at {L}{{X}}≳ 2× {10}37 erg s‑1. In order to identify the nature and spectral state of our sources, we compared their collective spectral properties based on single-component models (a simple power law or a multicolor disk) with the spectral evolution seen in representative Galactic LMXBs. We found that in the LX versus photon index {{{Γ }}}{PL} and LX versus disk temperature kTMCD plots, most of our sources fall on a narrow track in which the spectral shape hardens with increasing luminosity below {L}{{X}}∼ 7× {10}37 erg s‑1, but is relatively constant ({{{Γ }}}{PL}∼ 1.5 or {{kT}}{MCD}∼ 1.5 keV) above this luminosity, which is similar to the spectral evolution of Galactic neutron star (NS) LMXBs in the soft state in the Chandra bandpass. Therefore, we identified the track as the NS LMXB soft-state track and suggested sources with {L}{{X}}≲ 7× {10}37 erg s‑1 as atolls in the soft state and those with {L}{{X}}≳ 7× {10}37 erg s‑1 as Z sources. Ten other sources (five are transients) displayed significantly softer spectra and are probably black hole X-ray binaries in the thermal state. One of them (persistent) is in a metal-poor GC.

  13. The First Detection of [O IV] from an Ultraluminous X-ray Source with Spitzer. 2; Evidence for High Luminosity in Holmberg II ULX

    NASA Technical Reports Server (NTRS)

    Berghea, C. T.; Dudik, R. P.; Weaver, K. A.; Kallman, T. R.

    2009-01-01

    This is the second of two papers examining Spitzer Infrared Spectrograph (IRS) observations of the ultraluminous X-ray source (ULX) in Holmberg II. Here we perform detailed photoionization modeling of the infrared lines. Our analysis suggests that the luminosity and morphology of the [O IV] 25.89 micron emission line is consistent with photoionization by the soft X-ray and far ultraviolet (FUV) radiation from the accretion disk of the binary system and inconsistent with narrow beaming. We show that the emission nebula is matter-bounded both in the line of sight direction and to the east, and probably radiation-bounded to the west. A bolometric luminosity in excess of 10(exp 40) erg/s would be needed to produce the measured [O IV] flux. We use modeling and previously published studies to conclude that shocks likely contribute very little, if at all, to the high-excitation line fluxes observed in the Holmberg II ULX. Additionally, we find that the spectral type of the companion star has a surprisingly strong effect on the predicted strength of the [O IV] emission. This finding could explain the origin of [O IV] in some starburst systems containing black hole binaries.

  14. Spherically averaging ellipsoidal galaxy clusters in X-ray and Sunyaev-Zel'dovich studies - II. Biases

    NASA Astrophysics Data System (ADS)

    Buote, David A.; Humphrey, Philip J.

    2012-04-01

    This is the second of two papers investigating the spherical averaging of ellipsoidal galaxy clusters in the context of X-ray and Sunyaev-Zel'dovich (SZ) observations. In the present study, we quantify the orientation-average bias and scatter in observables that result from spherically averaging clusters described by either ellipsoidal generalizations of the Navarro-Frenk-White (NFW) profile or a nearly scale-free logarithmic potential. Although the mean biases are small and mostly <1 per cent, the flattest cluster models generally have a significant mean bias; i.e. averaging over all orientations does not always eliminate projection biases. Substantial biases can result from different viewing orientations, where the integrated Compton-y parameter (YSZ) and the concentration have the largest scatter (as large as σ˜ 10 per cent for YSZ), and the emission-weighted temperature (TX) has the smallest (σ≲ 0.5 per cent). The very small scatter for TX leads to YX and Mgas having virtually the same orientation biases. Substantial scatter is expected for individual clusters (up to σ˜ 8 per cent) in the correlation between YSZ and YX in comparison to the small mean bias (σ≲ 1 per cent) applicable to a random sample of clusters of sufficient size. For ellipsoidal NFW models, we show that the orientation bias for the total cluster mass attains a minimum near the radius r2500 so that the spherically averaged mass computed at this radius is always within ≈0.5 per cent of the true value for any orientation. Finally, to facilitate the accounting for orientation bias in X-ray and SZ cluster studies, we provide cubic polynomial approximations to the mean orientation bias and 1σ scatter for each cluster observable as a function of axial ratio for the ellipsoidal NFW models.

  15. Kinetic and X-ray crystallographic investigations on carbonic anhydrase isoforms I, II, IX and XII of a thioureido analog of SLC-0111.

    PubMed

    Lomelino, Carrie L; Mahon, Brian P; McKenna, Robert; Carta, Fabrizio; Supuran, Claudiu T

    2016-03-01

    SLC-0111 (4-(4-fluorophenylureido)-benzenesulfonamide) is the first carbonic anhydrase (CA, EC 4.2.1.1) IX inhibitor to reach phase I clinical trials as an antitumor/antimetastatic agent. Here we report a kinetic and X-ray crystallographic study of a congener of SLC-0111 which incorporates a thioureido instead of ureido linker between the two aromatic rings as inhibitor of four physiologically relevant CA isoforms. Similar to SLC-0111, the thioureido derivative was a weak hCA I and II inhibitor and a potent one against hCA IX and XII. X-ray crystallography of its adduct with hCA II and comparison of the structure with that of other five hCA II-sulfonamide adducts belonging to the SLC-0111 series, afforded us to understand the particular inhibition profile of the new sulfonamide. Similar to SLC-0111, the thioureido sulfonamide primarily interacted with the hydrophobic side of the hCA II active site, with the tail participating in van der Waals interactions with Phe131 and Pro202, in addition to the coordination of the deprotonated sulfonamide to the active site metal ion. On the contrary, the tail of other sulfonamides belonging to the SLC-0111 series (2-isopropyl-phenyl; 3-nitrophenyl) were orientated towards the hydrophilic half of the active site, which was correlated with orders of magnitude better inhibitory activity against hCA II, and a loss of selectivity for the inhibition of the tumor-associated CAs.

  16. SPATIALLY RESOLVED [Fe II] 1.64 {mu}m EMISSION IN NGC 5135: CLUES FOR UNDERSTANDING THE ORIGIN OF THE HARD X-RAYS IN LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Colina, L.; Pereira-Santaella, M.; Alonso-Herrero, A.; Arribas, S.; Bedregal, A. G.

    2012-04-20

    Spatially resolved near-IR and X-ray imaging of the central region of the luminous infrared galaxy (LIRG) NGC 5135 is presented. The kinematical signatures of strong outflows are detected in the [Fe II] 1.64 {mu}m emission line in a compact region at 0.9 kpc from the nucleus. The derived mechanical energy release is consistent with a supernova rate of 0.05-0.1 yr{sup -1}. The apex of the outflowing gas spatially coincides with the strongest [Fe II] emission peak and with the dominant component of the extranuclear hard X-ray emission. All these features provide evidence for a plausible direct physical link between supernova-driven outflows and the hard X-ray emitting gas in an LIRG. This result is consistent with model predictions of starbursts concentrated in small volumes and with high thermalization efficiencies. A single high-mass X-ray binary (HMXB) as the major source of the hard X-ray emission, although not favored, cannot be ruled out. Outside the active galactic nucleus, the hard X-ray emission in NGC 5135 appears to be dominated by the hot interstellar medium produced by supernova explosions in a compact star-forming region, and not by the emission due to HMXBs. If this scenario is common to (ultra)luminous infrared galaxies, the hard X-rays would only trace the most compact ({<=}100 pc) regions with high supernova and star formation densities, therefore a lower limit to their integrated star formation. The star formation rate derived in NGC 5135 based on its hard X-ray luminosity is a factor of two and four lower than the values obtained from the 24 {mu}m and soft X-ray luminosities, respectively.

  17. Jet-gas interactions and hotspots in FR I/II transition sources

    NASA Astrophysics Data System (ADS)

    Worrall, Diana; Birkinshaw, Mark

    2016-07-01

    Sources with intermediate FR I/II morphologies, and with powers in the decade straddling the FR I/II boundary, provide an opportunity to understand triggers responsible for the different workings of the two classes. Illustrated by deep Chandra observations of several sources, this presentation will show evidence that the physics changes within the transition range, and the work done in driving shocks can exceed that in evacuating the cavities common in FR I sources. Hotspots can be absent, seen only on one side (jet-side or counter-jet-side), or both, in which case X-ray/radio correspondence can be very different on the two sides. Evidence will be shown for radio-emitting plasma running along boundaries between gas of different temperature, apparently lubricating the gas flows and inhibiting heat transfer.

  18. X-ray beamsplitter

    DOEpatents

    Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

    1987-08-07

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

  19. X-ray beamsplitter

    DOEpatents

    Ceglio, Natale M.; Stearns, Daniel S.; Hawryluk, Andrew M.; Barbee, Jr., Troy W.

    1989-01-01

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

  20. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  1. X-ray

    MedlinePlus

    ... is very low. Most experts feel that the benefits of appropriate x-ray imaging greatly outweigh any risks. Young children and babies in the womb are more sensitive to the risks of x-rays. Tell your health care provider if you think you might be pregnant.

  2. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy.

    PubMed

    Miaja-Avila, L; O'Neil, G C; Uhlig, J; Cromer, C L; Dowell, M L; Jimenez, R; Hoover, A S; Silverman, K L; Ullom, J N

    2015-03-01

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼10(6) photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >10(7) laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments. PMID:26798792

  3. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    DOE PAGES

    Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; Cromer, C. L.; Dowell, M. L.; Jimenez, R.; Hoover, A. S.; Silverman, K. L.; Ullom, J. N.

    2015-03-02

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ~106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also presentmore » data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.« less

  4. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy.

    PubMed

    Miaja-Avila, L; O'Neil, G C; Uhlig, J; Cromer, C L; Dowell, M L; Jimenez, R; Hoover, A S; Silverman, K L; Ullom, J N

    2015-03-01

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼10(6) photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >10(7) laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

  5. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    SciTech Connect

    Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; Cromer, C. L.; Dowell, M. L.; Jimenez, R.; Hoover, A. S.; Silverman, K. L.; Ullom, J. N.

    2015-03-02

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ~106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

  6. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    PubMed Central

    Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; Cromer, C. L.; Dowell, M. L.; Jimenez, R.; Hoover, A. S.; Silverman, K. L.; Ullom, J. N.

    2015-01-01

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments. PMID:26798792

  7. [X-ray absorption fine structure (XAFS) study of the effects of pH on Pb(II) sorption by soil].

    PubMed

    Hu, Ning-Jing; Huang, Peng; Luo, Yong-Ming; Hu, Tian-Dou; Xie, Ya-Ning; Wu, Zi-Yu

    2010-12-01

    Combined batch sorption and in situ X-ray absorption fine structure (XAFS) provide direct assessment of the mechanisms for Pb(II) sorption at the soil-water interface under different pH conditions. The XAFS data indicated that the innersphere Pb sorption complex with ionic character (Pb4 (OH)4(4+)) dominated the Pb surface speciation, and the outer-sphere Pb sorption complex and the precipitation of calcium carbonate containing Pb(PbCaCO3) were also involved in the adsorption samples. Coordination number and radial distance of the first-shell Pb-O decreased from 0.172 7 to 0.166 6 nm and the percentage of inner-sphere complexes increased when the initial pH changed from 6.0 to 8.5, indicating that the mechanism of Pb(II) sorption by the soil was pH-dependent. PMID:21322254

  8. NMR studies of chiral P,S-chelate platinum, rhodium, and iridium complexes and the X-ray structure of a palladium(II) allyl derivative

    SciTech Connect

    Albinati, A.; Eckert, J.; Pregosin, P.; Ruegger, H.; Salzmann, R.; Stoessel, C.

    1997-02-18

    Several Rh(I), Ir(III), and Pt(II) complexes of the chiral P,S-bidentate ligand 2 have been prepared and characterized. Detailed two-dimensional NMR studies show that (i) the boat-type chelate ring and the stereogenic sulfur center can invert rapidly at ambient temperature and (ii) the sulfur donor may dissociate, essentially destroying the chiral pocket. The solid-state structure of [Pt({eta}{sup 3}-C{sub 3}H{sub 5})(2)]PF{sub 6} (3) has been determined and the sulfur substituent shown to have an axial orientation. The six-membered chelate ring takes up a boat-like conformation. As shown by an X-ray diffraction study for 3, and via incoherent inelastic neutron scattering (IINS) measurements for the Pd analog, 4, the OH group is remote from the metal atom. 42 refs., 11 figs., 6 tabs.

  9. X-ray generator

    DOEpatents

    Dawson, John M.

    1976-01-01

    Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

  10. Structural and Electronic Snapshots during the Transition from a Cu(II) to Cu(I) Metal Center of a Lytic Polysaccharide Monooxygenase by X-ray Photoreduction*

    PubMed Central

    Gudmundsson, Mikael; Kim, Seonah; Wu, Miao; Ishida, Takuya; Momeni, Majid Hadadd; Vaaje-Kolstad, Gustav; Lundberg, Daniel; Royant, Antoine; Ståhlberg, Jerry; Eijsink, Vincent G. H.; Beckham, Gregg T.; Sandgren, Mats

    2014-01-01

    Lytic polysaccharide monooxygenases (LPMOs) are a recently discovered class of enzymes that employ a copper-mediated, oxidative mechanism to cleave glycosidic bonds. The LPMO catalytic mechanism likely requires that molecular oxygen first binds to Cu(I), but the oxidation state in many reported LPMO structures is ambiguous, and the changes in the LPMO active site required to accommodate both oxidation states of copper have not been fully elucidated. Here, a diffraction data collection strategy minimizing the deposited x-ray dose was used to solve the crystal structure of a chitin-specific LPMO from Enterococcus faecalis (EfaCBM33A) in the Cu(II)-bound form. Subsequently, the crystalline protein was photoreduced in the x-ray beam, which revealed structural changes associated with the conversion from the initial Cu(II)-oxidized form with two coordinated water molecules, which adopts a trigonal bipyramidal geometry, to a reduced Cu(I) form in a T-shaped geometry with no coordinated water molecules. A comprehensive survey of Cu(II) and Cu(I) structures in the Cambridge Structural Database unambiguously shows that the geometries observed in the least and most reduced structures reflect binding of Cu(II) and Cu(I), respectively. Quantum mechanical calculations of the oxidized and reduced active sites reveal little change in the electronic structure of the active site measured by the active site partial charges. Together with a previous theoretical investigation of a fungal LPMO, this suggests significant functional plasticity in LPMO active sites. Overall, this study provides molecular snapshots along the reduction process to activate the LPMO catalytic machinery and provides a general method for solving LPMO structures in both copper oxidation states. PMID:24828494

  11. Dicoumarol complexes of Cu(II) based on 1,10-phenanthroline: Synthesis, X-ray diffraction studies, thermal behavior and biological evaluation

    NASA Astrophysics Data System (ADS)

    Dholariya, Hitesh R.; Patel, Ketan S.; Patel, Jiten C.; Patel, Kanuprasad D.

    2013-05-01

    A series of Cu(II) complexes containing dicoumarol derivatives and 1, 10-phenanthroline have been synthesized. Structural and spectroscopic properties of ligands were studied on the basis of mass spectra, NMR (1H and 13C) spectra, FT-IR spectrophotometry and elemental analysis, while physico-chemical, spectroscopic and thermal properties of mixed ligand complexes have been studied on the basis of infrared spectra, mass spectra, electronic spectra, powder X-ray diffraction, elemental analysis and thermogravimetric analysis. X-ray diffraction study suggested the suitable octahedral geometry for hexa-coordinated state. The kinetic parameters such as order of reaction (n), energy of activation (Ea), entropy (S*), pre-exponential factor (A), enthalpy (H*) and Gibbs free energy (G*) have been calculated using Freeman-Carroll method. Ferric-reducing antioxidant power (FRAP) of all complexes were measured. All the compounds were screened for their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Streptococcus pyogenes and Bacillus subtilis, while antifungal activity against Candida albicans and Aspergillus niger have been carried out. Also compounds against Mycobacterium tuberculosis shows clear enhancement in the anti-tubercular activity upon copper complexation.

  12. Aqueous Cu(II)-organic complexation studied in situ using soft X-ray and vibrational spectroscopies.

    PubMed

    Phillips, Courtney L; Regier, Tom Z; Peak, Derek

    2013-12-17

    In situ aqueous solutions containing copper-ligand mixtures were measured at the Cu L-edge using X-ray absorption near edge structure (XANES) and with attenuated total reflectance infrared (ATR-FTIR) spectroscopies. Copper complexation with environmentally relevant ligands such as EDTA, citrate, and malate provided a bridge between spectroscopic studies and general environmental behavior and will allow for future study of complex environmental samples. XANES results show that the lowest unoccupied molecular orbital (LUMO) energy is governed by the ligand field strength and is related to Lewis acid/base properties of the ligand functional groups. Complementary ATR-FTIR studies confirmed the importance of water molecules in the structure of these Cu-ligand complexes and provided in-depth structural analysis to support the XANES data. Copper-malate is shown to have a 5/6-O-ring structure, and Cu-ethylenediaminetetraacetate has pentadentate coordination. Cu L-edge XANES also revealed direct Cu-N coordination in these aqueous solutions with amide functional groups. PMID:24261818

  13. Optical studies of the X-ray transient XTE J2123-058 - II. Phase-resolved spectroscopy

    NASA Astrophysics Data System (ADS)

    Hynes, R. I.; Charles, P. A.; Haswell, C. A.; Casares, J.; Zurita, C.; Serra-Ricart, M.

    2001-06-01

    We present time-resolved spectroscopy of the soft X-ray transient XTEJ2123-058 in outburst. A useful spectral coverage of 3700-6700Å was achieved spanning two orbits of the binary, with single-epoch coverage extending to ~9000Å. The optical spectrum approximates a steep blue power law, consistent with emission on the Rayleigh-Jeans tail of a hot blackbody spectrum. The strongest spectral lines are Heii 4686Å and Ciii/Niii 4640Å (Bowen blend) in emission. Their relative strengths suggest that XTEJ2123-058 was formed in the Galactic plane, not in the halo. Other weak emission lines of Heii and Civ are present, and Balmer lines show a complex structure, blended with Heii. Heii 4686-Å profiles show a complex multiple S-wave structure, with the strongest component appearing at low velocities in the lower-left quadrant of a Doppler tomogram. Hα shows transient absorption between phases 0.35 and 0.55. Both of these effects appear to be analogous to similar behaviour in SW Sex type cataclysmic variables. We therefore consider whether the spectral line behaviour of XTEJ2123-058 can be explained by the same models invoked for those systems.

  14. Quantitative determination of the oxidation state of iron in biotite using x-ray photoelectron spectroscopy: II. In situ analyses

    SciTech Connect

    Raeburn, S.P. |; Ilton, E.S.; Veblen, D.R.

    1997-11-01

    X-ray photoelectron spectroscopy (XPS) was used to determine Fe(III)/{Sigma}Fe in individual biotite crystals in thin sections of ten metapelites and one syenite. The in situ XPS analyses of Fe(III)/{Sigma}Fe in biotite crystals in the metapelites were compared with published Fe(III)/{Sigma}Fe values determined by Moessbauer spectroscopy (MS) for mineral separates from the same hand samples. The difference between Fe(III)/{Sigma}Fe by the two techniques was greatest for samples with the lowest Fe(III)/{Sigma}Fe (by MS). For eight metamorphic biotites with Fe(III)/{Sigma}Fe = 9-27% comparison of the two techniques yielded a linear correlation of r = 0.94 and a statistically acceptable fit of [Fe(III)/{Sigma}Fe]{sub xps} = [Fe(III)/{Sigma}Fe]{sub ms}. The difference between Fe(III)/{Sigma}Fe by the two techniques was greater for two samples with Fe(III)/{Sigma}Fe {le} 6% (by MS). For biotite in the syenite sample, Fe(III)/{Sigma}Fe determined by both in situ XPS and bulk wet chemistry/electron probe microanalysis were similar. This contribution demonstrates that XPS can be used to analyze bulk Fe(III)/{Sigma}Fe in minerals in thin sections when appropriate precautions taken to avoid oxidation of the near-surface during preparation of samples. 25 refs., 3 figs., 4 tabs.

  15. IMPULSIVE ACCELERATION OF CORONAL MASS EJECTIONS. II. RELATION TO SOFT X-RAY FLARES AND FILAMENT ERUPTIONS

    SciTech Connect

    Bein, B. M.; Berkebile-Stoiser, S.; Veronig, A. M.; Temmer, M.; Vrsnak, B.

    2012-08-10

    Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher peak accelerations and lower acceleration phase durations, initiation heights, and heights, at which they reach their peak velocities and peak accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME peak acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME acceleration duration and negatively correlated with the CME peak acceleration. For the majority of the events the CME acceleration starts before the flare onset (for 75% of the events) and the CME acceleration ends after the soft X-ray (SXR) peak time (for 77% of the events). In {approx}60% of the events, the time difference between the peak time of the flare SXR flux derivative and the peak time of the CME acceleration is smaller than {+-}5 minutes, which hints at a feedback relationship between the CME acceleration and the energy release in the associated flare due to magnetic reconnection.

  16. Aqueous Cu(II)-organic complexation studied in situ using soft X-ray and vibrational spectroscopies.

    PubMed

    Phillips, Courtney L; Regier, Tom Z; Peak, Derek

    2013-12-17

    In situ aqueous solutions containing copper-ligand mixtures were measured at the Cu L-edge using X-ray absorption near edge structure (XANES) and with attenuated total reflectance infrared (ATR-FTIR) spectroscopies. Copper complexation with environmentally relevant ligands such as EDTA, citrate, and malate provided a bridge between spectroscopic studies and general environmental behavior and will allow for future study of complex environmental samples. XANES results show that the lowest unoccupied molecular orbital (LUMO) energy is governed by the ligand field strength and is related to Lewis acid/base properties of the ligand functional groups. Complementary ATR-FTIR studies confirmed the importance of water molecules in the structure of these Cu-ligand complexes and provided in-depth structural analysis to support the XANES data. Copper-malate is shown to have a 5/6-O-ring structure, and Cu-ethylenediaminetetraacetate has pentadentate coordination. Cu L-edge XANES also revealed direct Cu-N coordination in these aqueous solutions with amide functional groups.

  17. The magnetohydrodynamical model of kilohertz quasi-periodic oscillations in neutron star low-mass X-ray binaries (II)

    SciTech Connect

    Shi, Chang-Sheng; Zhang, Shuang-Nan; Li, Xiang-Dong

    2014-08-10

    We study the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low-mass X-ray binaries (LMXBs) with a new magnetohydrodynamics (MHD) model, in which the compressed magnetosphere is considered. The previous MHD model is reexamined and the relation between the frequencies of the kHz QPOs and the accretion rate in LMXBs is obtained. Our result agrees with the observations of six sources (4U 0614+09, 4U 1636-53, 4U 1608-52, 4U 1915-15, 4U 1728-34, and XTE 1807-294) with measured spins. In this model, the kHz QPOs originate from the MHD waves in the compressed magnetosphere. The single kHz QPOs and twin kHz QPOs are produced in two different parts of the accretion disk and the boundary is close to the corotation radius. The lower QPO frequency in a frequency-accretion rate diagram is cut off at a low accretion rate and the twin kHz QPOs encounter a top ceiling at a high accretion rate due to the restriction of the innermost stable circular orbit.

  18. X-ray crystallography

    NASA Technical Reports Server (NTRS)

    2001-01-01

    X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

  19. Laboratory x ray lasers

    NASA Astrophysics Data System (ADS)

    Matthews, D. L.

    1989-08-01

    One of the most innovative spinoffs of ICF technology and physics was the development of the x ray wavelength laser. The first incontrovertible demonstration of this type of laser came from LLNL in 1984 using the Novette laser to pump a selenium foil target. The power and energy of Novette were then needed to produce a column of plasma of sufficient length to achieve a sufficient gainlength product (approximately 5.5, this corresponds to an amplification of approximately 250X) that could unquestionably illustrate the lasing effect. LLNL ICF expertise was also required to develop time-resolved spectrometers used to view the lasing transitions at approximately 20 nm, a region of the XUV spectrum normally dominated by high backgrounds. The design of the x ray laser amplifier, which required maintaining nonequilibrium level populations in a tailored plasma having the proper conditions for gain and x ray laser beam propagation, was accomplished with modified versions of ICF kinetics and hydrodynamics codes. Since the first demonstration, progress in the development of the x ray laser was rapid. New achievements include production of megawatt power levels at 20 nm, amplified spontaneous emission levels approaching saturation intensity GL of approximately 17 at 20 nm, efficiency (x ray laser energy/pump energy) approximately 10(exp 6), the demonstration of double and triple pass amplification (hinting at the possibility of producing x ray wavelength resonators), the focusing of x ray lasers to pump other types of lasers and the first demonstration of an x ray hologram produced by an x ray laser. The generation of amplification at ever shorter wavelength is possible using various types of inversion schemes. We depict below this progress benchmarked against production of gain in the water window (2.2 to 4.4 nm,), where applications to biological imaging may be facilitated.

  20. Lumbosacral spine x-ray

    MedlinePlus

    X-ray - lumbosacral spine; X-ray - lower spine ... The test is done in a hospital x-ray department or your health care provider's office by an x-ray technician. You will be asked to lie on the x-ray table ...

  1. X-ray laser

    DOEpatents

    Nilsen, Joseph

    1991-01-01

    An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

  2. Hard X-Ray Emission from X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.; Kaaret, Philip

    1999-01-01

    The scientific goal of this project is to study the hard x-ray emission from x-ray bursters. One target of opportunity observation was made for this investigation during 1997. We obtained 38ks of data on the source 4UI705-44. The project is closely related to "Monitoring x-ray emission from x-ray bursters", and "Long-Term Hard X-Ray Monitoring of X-Ray Bursters."

  3. Simultaneous Ultraviolet and X-Ray Observations of the Seyfert Galaxy NGC 4151. II. Physical Conditions in the UV Absorbers

    NASA Astrophysics Data System (ADS)

    Kraemer, S. B.; Crenshaw, D. M.; Gabel, J. R.; Kriss, G. A.; Netzer, H.; Peterson, B. M.; George, I. M.; Gull, T. R.; Hutchings, J. B.; Mushotzky, R. F.; Turner, T. J.

    2006-12-01

    We present a detailed analysis, including photoionization modeling, of the intrinsic absorption in the Seyfert 1 galaxy NGC 4151 using ultraviolet (UV) spectra from the Hubble Space Telescope Space Telescope Imaging Spectrograph and the Far Ultraviolet Spectrographic Explorer obtained 2002 May as part of a set of contemporaneous observations that included Chandra High Energy Transmission Grating Spectrometer spectra. In our analysis of the Chandra spectra, we determined that the X-ray absorption was dominated by two components: a high-ionization absorber, revealed by the presence of H-like and He-like lines of Mg, Si, and S, and a lower ionization absorber, in which inner shell absorption lines from lower ionization species of these elements formed. We identified the latter as the source of the saturated UV lines of O VI, C IV, and N V associated with the absorption feature at a radial velocity of ~-500 km s-1, which we referred to as component D+E. In the present work, we have derived tighter constrains on the line-of-sight covering factors, densities, and radial distances of the absorbers. We confirm the presence of the three subcomponents of D+E described in our previous paper, with line-of-sight covering factors (Clos) ranging from ~0.5 to 0.9, and find evidence for a fourth component, D+Ed, characterized by low ionization and a Clos~0.2. The complexity of the UV absorption in NGC 4151 may be a consequence of the fact that we are viewing the black hole/accretion disk system at a relatively high inclination and, therefore, may be detecting the densest part of the flow. Our deconvolution of the underlying C IV emission indicates that D+E must lie outside the intermediate line region (ILR), hence at a radial distance of ~0.1 pc. We find that the equivalent widths (EWs) of the low-ionization lines associated with D+E varied over the period from 1999 July to 2002 May. Although over part of this time, the variations were correlated with changes in the UV continuum

  4. Structures of (001) twist boundaries in gold. II. Results obtained by x-ray diffraction and computer simulation

    SciTech Connect

    Majid, I.; Bristowe, P.D.; Balluffi, R.W. )

    1989-08-15

    Absolute grain-boundary structure factors, {vert bar}{ital F}{sub {ital b}}{vert bar}, were measured for a series of (001) twist boundaries in gold by the x-ray-diffraction method described in the preceding paper. The series included the {Sigma}113({theta}=7.6{degree}), {Sigma}25({theta}=16.3{degree}), {Sigma}13({theta}=22.6{degree}), {Sigma}17({theta}=28.1{degree}), and {Sigma}5({theta}=36.9{degree}) boundaries ({theta} being the twist angle). The atomistic structures and {vert bar}{ital F}{sub {ital b}}{vert bar}'s of these boundaries were also calculated by computer simulation using the embedded-atom model. The calculated atomic relaxations in the boundary cores consisted mainly of rotations around the {ital O} lattice elements, in agreement with previous work, and became monotonically weaker as {theta} increased. A considerable degree of consistency between measured and calculated {vert bar}{ital F}{sub {ital b}}{vert bar}'s was obtained for all five boundaries. The calculated results faithfully tracked large measured decreases in {vert bar}{ital F}{sub {ital b}}{vert bar} as {theta} increased. Considerable consistency was found between measured and calculated sets of {vert bar}{ital F}{sub {ital b}}{vert bar}'s for individual boundaries, particularly for {Sigma}113 and {Sigma}25, where the scattering was relatively strong. For the weakly scattering {Sigma}5 boundary, the observed {vert bar}{ital F}{sub {ital b}}{vert bar}'s led to a most probable structure with small displacements which closely resembled the calculated structure. For the intermediate {Sigma}13 and {Sigma}17 boundaries, the limited number of measured {vert bar}{ital F}{sub {ital b}}{vert bar}'s was reasonably consistent with calculated values. It was therefore concluded that the atomistic boundary structures calculated by the embedded-atom model were essentially correct.

  5. X-ray magnetic circular dichroism in d and f ferromagnetic materials: recent theoretical progress. Part II (Review Article)

    NASA Astrophysics Data System (ADS)

    Antonov, V. N.; Shpak, A. P.; Yaresko, A. N.

    2008-02-01

    The present state of theoretical understanding of the x-ray magnetic circular dichroism (XMCD) of 4f and 5f compounds is reviewed. Energy band theory based upon the local spin-density approximation (LSDA) describes the XMCD spectra of transition metal compounds with high accuracy. However, the LSDA does not suffice for lanthanide compounds which have a correlated 4f shell. A satisfactory description of the XMCD spectra could be obtained by using a generalization of the LSDA, in which explicitly f electron Coulomb correlations are taken into account (LSDA +U approach). As examples of this group we consider the compound GdN. We also consider uranium 5f compounds. In those compounds where the 5f electrons are rather delocalized, the LSDA describes the XMCD spectra reasonably well. As an example of this group we consider UFe2. Particular differences occur for uranium compounds in which the 5f electrons are neither delocalized nor localized, but more or less semilocalized. Typical examples are UXAl (X =Co, Rh, and Pt), and UX (X =S, Se, Te). However, the semilocalized 5f's are not inert, but their interaction with conduction electrons plays an important role. We also consider the electronic structure and XMCD spectra of the heavy-fermion compounds UPt3, URu2Si2, UPd2Al3, UNi2Al3, and UBe13, where the degree of the 5f localization is increased in comparison with other uranium compounds. The electronic structure and XMCD spectra of UGe2 which possesses simultaneously ferromagnetism and superconductivity also presented. Recently achieved improvements for describing 5f compounds are discussed.

  6. X-ray (image)

    MedlinePlus

    ... a form of electromagnetic radiation, just like visible light. Structures that are dense (such as bone) will block most of the x-ray particles, and will appear white. Metal and contrast media (special dye used to highlight ...

  7. Pelvis x-ray

    MedlinePlus

    X-ray - pelvis ... Tumors Degenerative conditions of bones in the hips, pelvis, and upper legs ... hip joint Tumors of the bones of the pelvis Sacroiliitis (inflammation of the area where the sacrum ...

  8. Medical X-Rays

    MedlinePlus

    ... Diagnostic X-Ray Equipment Compliance Program Guidance Manual CP 7386.003 Field Compliance Testing of Diagnostic (Medical) ... and Exporting Electronic Products Compliance Program Guidance Manual CP 7386.003 Field Compliance Testing of Diagnostic (Medical) ...

  9. X-Ray Diffraction.

    ERIC Educational Resources Information Center

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  10. X-ray - skeleton

    MedlinePlus

    ... is used to look for: Fractures or broken bone Cancer that has spread to other areas of the ... 2014:chap 8. Read More Bone tumor Broken bone Cancer Metastasis Osteomyelitis X-ray Update Date 5/9/ ...

  11. Time-dependent simulation of the gas attenuator for the LCLS-II X-ray FEL's under high beam power operations

    NASA Astrophysics Data System (ADS)

    Feng, Yiping; Krzywinski, Jacek; Schafer, Donald W.; Ortiz, Eliazar; Rowen, Michael; Raubenheimer, Tor O.

    2015-09-01

    Time-dependent simulation was carried out to study the dynamic response of a gas-based attenuator system designed for the LCLS-II high repetition rate X-ray Free-electron Laser's, and to further elucidate the impact of the fluctuating energies of proceeding pulses on the actual attenuation factor achieved for the trailing pulses. The filamentation effect in the gas density revealed from an earlier steady-state calculation under a constant Continuous-Wave input power was reproduced with additional ramping behavior and oscillations arising from the onset and the pulsed structure of the beam. More importantly, the actual achieved attenuation for a given pulse was found to vary randomly in response to the fluctuations in the input power.

  12. Measurement of coherence length and incoherent source size of hard x-ray undulator beamline at Pohang Light Source-II

    SciTech Connect

    Park, So Yeong; Hong, Chung Ki; Lim, Jun

    2014-04-15

    We measured the spatial coherence length and incoherent source size of a hard x-ray undulator beamline at Pohang Light Source-II, the stored electron energy of which has been increased from 2.5 GeV to 3 GeV. The coherence length was determined by single-slit measurement of the visibility of the Fresnel diffraction pattern. The correlated incoherent source size was cross-checked for three different optics: the single slit, beryllium parabolic compound refractive lenses, and the Fresnel zone plate. We concluded that the undulator beamline has an effective incoherent source size (FWHM) of 540 μm (horizontal) × 50 μm (vertical)

  13. Time-Resolved X-ray Spectroscopy in the Water Window: Elucidating Transient Valence Charge Distributions in an Aqueous Fe(II) Complex.

    PubMed

    Van Kuiken, Benjamin E; Cho, Hana; Hong, Kiryong; Khalil, Munira; Schoenlein, Robert W; Kim, Tae Kyu; Huse, Nils

    2016-02-01

    Time-resolved nitrogen-1s spectroscopy in the X-ray water window is presented as a novel probe of metal-ligand interactions and transient states in nitrogen-containing organic compounds. New information on iron(II) polypyridyl complexes via nitrogen core-level transitions yields insight into the charge density of the photoinduced high-spin state by comparing experimental results with time-dependent density functional theory. In the transient high-spin state, the 3d electrons of the metal center are more delocalized over the nearest-neighbor nitrogen atoms despite increased bond lengths. Our findings point to a strong coupling of electronic states with charge-transfer character, facilitating the ultrafast intersystem crossing cascade in these systems. The study also highlights the importance of local charge density measures to complement chemical interaction concepts of charge donation and back-bonding with molecular orbital descriptions of states. PMID:26727390

  14. Internal structure of copper(II)-phthalocyanine thin films on SiO{sub 2}/Si substrates investigated by grazing incidence x-ray reflectometry

    SciTech Connect

    Brieva, A. C.; Jenkins, T. E.; Jones, D. G.; Stroessner, F.; Evans, D. A.; Clark, G. F.

    2006-04-01

    The internal structure of copper(II)-phthalocyanine (CuPc) thin films grown on SiO{sub 2}/Si by organic molecular beam deposition has been studied by grazing incidence x-ray reflectometry (GIXR) and atomic force microscopy. The electronic density profile is consistent with a structure formed by successive monolayers of molecules in the {alpha} form with the b axis lying in the substrate surface plane. The authors present an electronic density profile model of CuPc films grown on SiO{sub 2}/Si. The excellent agreement between the model and experimental data allows postdeposition monitoring of the internal structure of the CuPc films with the nondestructive GIXR technique, providing a tool for accurate control of CuPc growth on silicon-based substrates. In addition, since the experiments have been carried out ex situ, they show that these structures can endure ambient conditions.

  15. Time-Resolved X-ray Spectroscopy in the Water Window: Elucidating Transient Valence Charge Distributions in an Aqueous Fe(II) Complex.

    PubMed

    Van Kuiken, Benjamin E; Cho, Hana; Hong, Kiryong; Khalil, Munira; Schoenlein, Robert W; Kim, Tae Kyu; Huse, Nils

    2016-02-01

    Time-resolved nitrogen-1s spectroscopy in the X-ray water window is presented as a novel probe of metal-ligand interactions and transient states in nitrogen-containing organic compounds. New information on iron(II) polypyridyl complexes via nitrogen core-level transitions yields insight into the charge density of the photoinduced high-spin state by comparing experimental results with time-dependent density functional theory. In the transient high-spin state, the 3d electrons of the metal center are more delocalized over the nearest-neighbor nitrogen atoms despite increased bond lengths. Our findings point to a strong coupling of electronic states with charge-transfer character, facilitating the ultrafast intersystem crossing cascade in these systems. The study also highlights the importance of local charge density measures to complement chemical interaction concepts of charge donation and back-bonding with molecular orbital descriptions of states.

  16. Implementation of a multichannel soft x-ray diagnostic for electron temperature measurements in TJ-II high-density plasmas

    SciTech Connect

    Baiao, D.; Varandas, C.; Molinero, A.; Chercoles, J.

    2012-10-15

    Based on the multi-foil technique, a multichannel soft x-ray diagnostic for electron temperature measurements has been recently implemented in the TJ-II stellarator. The diagnostic system is composed by four photodiodes arrays with beryllium filters of different thickness. An in-vacuum amplifier board is coupled to each array, aiming at preventing induced noise currents. The Thomson scattering and the vacuum ultraviolet survey diagnostics are used for assessing plasma profiles and composition, being the analysis carried out with the radiation code IONEQ. The electron temperature is determined through the different signal-pair ratios with temporal and spatial resolution. The design and preliminary results from the diagnostic are presented.

  17. Automated suppression of errors in LTP-II slope measurements of x-ray optics. Part 2: Specification for automated rotating/flipping/aligning system

    SciTech Connect

    Ali, Zulfiqar; Yashchuk, Valeriy V.

    2011-07-11

    Systematic error and instrumental drift are the major limiting factors of sub-microradian slope metrology with state-of-the-art x-ray optics. Significant suppression of the errors can be achieved by using an optimal measurement strategy suggested in [Rev. Sci. Instrum. 80, 115101 (2009)]. With this series of LSBL Notes, we report on development of an automated, kinematic, rotational system that provides fully controlled flipping, tilting, and shifting of a surface under test. The system is integrated into the Advanced Light Source long trace profiler, LTP-II, allowing for complete realization of the advantages of the optimal measurement strategy method. We provide details of the system?s design, operational control and data acquisition. The high performance of the system is demonstrated via the results of high precision measurements with a spherical test mirror.

  18. X-rays Flares and Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Feigelson, Eric D.

    2011-04-01

    X-ray observations of star forming regions show that magnetic reconnection flares are powerful and frequent in pre-main sequence solar-type stars. Well-defined samples in the Orion Nebula Cluster and Taurus clouds exhibit flares with peak X- ray luminosities Lx˜10^29 - 10^32 erg/s, orders of magnitude stronger and more frequent than contemporary solar flares. X-rays are emitted in magnetic loops extending 0.1-10 R * above the stellar surface and thus have a favorable geometry to irradiate the protoplanetary disk. Several lines of evidence - fluorescent iron X-ray emission line, forbidden [NeII] infrared line, and excited molecular bands - support X-ray irradiation of cold material in some young systems. Several astrophysical consequences of X-ray irradiation are outlined. As ionization fractions need only reach 10-12 to induce the magnetorotational instability and associated turbulence, X-rays may be the principal determinant of the extent of the viscous "active zone" and laminar "dead zone" in the layered accretion disk. X-ray irradiation may thus play a major role in planet formation processes: particle settling; meter-size inspiral; protoplanetary migration; and dissipation of the gaseous disk.

  19. The X-ray absorption spectroscopic model of the copper(II) imidazole complex ion in liquid aqueous solution: a strongly solvated square pyramid.

    PubMed

    Frank, Patrick; Benfatto, Maurizio; Hedman, Britt; Hodgson, Keith O

    2012-02-20

    Cu K-edge extended X-ray absorption fine structure (EXAFS) and Minuit X-ray absorption near-edge structure (MXAN) analyses were combined to evaluate the structure of the copper(II) imidazole complex ion in liquid aqueous solution. Both methods converged to the same square-pyramidal inner coordination sphere [Cu(Im)(4)L(ax)](2+) (L(ax) indeterminate) with four equatorial nitrogen atoms at EXAFS, 2.02 ± 0.01 Å, and MXAN, 1.99 ± 0.03 Å. A short-axial N/O scatterer (L(ax)) was found at 2.12 ± 0.02 Å (EXAFS) or 2.14 ± 0.06 Å (MXAN). A second but very weak axial Cu-N/O interaction was found at 2.9 ± 0.1 Å (EXAFS) or 3.0 ± 0.1 Å (MXAN). In the MXAN fits, only a square-pyramidal structural model successfully reproduced the doubled maximum of the rising K-edge X-ray absorption spectrum, specifically excluding an octahedral model. Both EXAFS and MXAN also found eight outlying oxygen scatterers at 4.2 ± 0.3 Å that contributed significant intensity over the entire spectral energy range. Two prominent rising K-edge shoulders at 8987.1 and 8990.5 eV were found to reflect multiple scattering from the 3.0 Å axial scatterer and the imidazole rings, respectively. In the MXAN fits, the imidazole rings took in-plane rotationally staggered positions about copper. The combined (EXAFS and MXAN) model for the unconstrained cupric imidazole complex ion in liquid aqueous solution is an axially elongated square-pyramidal core, with a weak nonbonded interaction at the second axial coordination position and a solvation shell of eight nearest-neighbor water molecules. This core square-pyramidal motif has persisted through [Cu(H(2)O)(5)](2+), [Cu(NH(3))(4)(NH(3),H(2)O)](2+), (1, 2) and now [Cu(Im)(4)L(ax))](2+) and appears to be the geometry preferred by unconstrained aqueous-phase copper(II) complex ions. PMID:22316238

  20. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1992-01-01

    This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

  1. Oxidation and deprotonation of synthetic Fe{sup II}-Fe{sup III} (oxy)hydroxycarbonate Green Rust: An X-ray photoelectron study

    SciTech Connect

    Mullet, M. Guillemin, Y.; Ruby, C.

    2008-01-15

    X-ray photoelectron spectroscopy (XPS) was used to investigate chemical bonding and distribution of iron and oxygen species at the surface of Green Rusts (GRs). GRs with variable composition, i.e. Fe{sup II}{sub 6(1-x)}Fe{sup III}{sub 6x}O{sub 12}H{sub 2(7-3x)} CO{sub 3}.3H{sub 2}O where the Fe{sup III} molar fraction of the positively charged hydroxide sheets, x=[Fe(III)]/[Fe(total)] belongs to [1/3, 1], were synthesised under an inert atmosphere. The broadened Fe(2p{sub 3/2}) spectra were fitted using Gupta and Sen multiplets peaks and additional satellite and surface features. The [Fe(III)]/[Fe(total)] surface atomic ratios closely agree with the x ratios expected from the bulk composition, which gives a high degree of confidence on the validity of the proposed fitting procedure. The valence band spectra are also reported and show dependencies on iron speciation. The O(1s) spectra revealed the presence of O{sup 2-}, OH{sup -} species and adsorbed water. The hydroxyl component decreases with increasing x values, i.e. with the amount of ferric iron, while the oxide component increases. This study provides direct spectroscopic evidence of the deprotonation of hydroxyl groups that occurs simultaneously with the oxidation of ferrous iron within the GR structure. - Graphical abstract: X-ray photoelectron spectroscopy (XPS) is used to investigate chemical bonding and distribution of iron and oxygen species at the surface of Green Rust (GR) compounds. First spectroscopic evidence of the deprotonation of hydroxyls groups occurring simultaneously to the oxidation of Fe(II) into Fe(III) species is provided.

  2. Crystal structure of carnidazole form II from synchrotron X-ray powder diffraction: structural comparison with form I, the hydrated form and the low energy conformations in vacuo.

    PubMed

    de Armas, Héctor Novoa; Peeters, Oswald M; Blaton, Norbert; Van den Mooter, Guy; De Ridder, Dirk J A; Schenk, Henk

    2006-10-01

    The crystal structure of carnidazole form II, O-methyl [2-(2-methyl-5-nitro-1H-imidazole-1-yl)ethyl]thiocarbamate, has been determined using synchrotron X-ray powder diffraction in combination with simulated annealing and whole profile pattern matching, and refined by the Rietveld method. For structure solution, 12 degrees of freedom were defined: one motion group and six torsions. Form II crystallizes in space group P2(1)/n, Z=4, with unit cell parameters after Rietveld refinement: a=13.915(4), b=8.095(2), c=10.649(3) A, beta=110.83(1) degrees, and V=1121.1(5) A3. The two polymorphic forms, as well as the hydrate, crystallize in the monoclinic space group P2(1)/n having four molecules in the cell. In form II, the molecules are held together by forming two infinite zig-zag chains via hydrogen bonds of the type N--H...N, the same pattern as in form I. A conformational study of carnidazole, at semiempirical PM3 level, was performed using stochastic approaches based on modification of the flexible torsion angles. The values of the torsion angles for the molecules of the two polymorphic forms and the hydrate of carnidazole are compared to those obtained from the conformational search. Form I and form II are enantiotropic polymorphic pairs this agrees with the fact that the two forms are conformational polymorphs.

  3. X-ray structure and mechanism of RNA polymerase II stalled at an antineoplastic monofunctional platinum-DNA adduct

    PubMed Central

    Wang, Dong; Zhu, Guangyu; Huang, Xuhui; Lippard, Stephen J.

    2010-01-01

    DNA is a major target of anticancer drugs. The resulting adducts interfere with key cellular processes, such as transcription, to trigger downstream events responsible for drug activity. cis-Diammine(pyridine)chloroplatinum(II), cDPCP or pyriplatin, is a monofunctional platinum(II) analogue of the widely used anticancer drug cisplatin having significant anticancer properties with a different spectrum of activity. Its novel structure-activity properties hold promise for overcoming drug resistance and improving the spectrum of treatable cancers over those responsive to cisplatin. However, the detailed molecular mechanism by which cells process DNA modified by pyriplatin and related monofunctional complexes is not at all understood. Here we report the structure of a transcribing RNA polymerase II (pol II) complex stalled at a site-specific monofunctional pyriplatin-DNA adduct in the active site. The results reveal a molecular mechanism of pol II transcription inhibition and drug action that is dramatically different from transcription inhibition by cisplatin and UV-induced 1,2-intrastrand cross-links. Our findings provide insight into structure-activity relationships that may apply to the entire family of monofunctional DNA-damaging agents and pave the way for rational improvement of monofunctional platinum anticancer drugs. PMID:20448203

  4. The development of MWPC-based systems for imaging X-rays, gamma rays and charged particles in applications in medicine, materials science and biochemistry. Part II. Applications in medicine, biology, low energy and X-ray physics

    NASA Astrophysics Data System (ADS)

    Bateman, J. E.; Connolly, J. F.; Stephenson, R.; Tappern, G. J. R.; Flesher, A. C.

    1983-11-01

    The development is described of several complete MWPC based imaging systems for applications in medicine (a positron camera), industry (a second positron camera), materials science (two 2-d X-ray diffraction systems) and biochemistry (an autoradiography system for 2-d immunoelectrophoresis using a tritium label). A moderately detailed description of two of the system is given and some special developments in the areas of fast modular electronics for the delay line readout technique and fast imaging data taking are described in more detail. The state of rapid expansion of this area of application of MWPC technology and its relationship to the microprocessor revolution are discussed.

  5. Use of X-ray absorption spectroscopy and esterification to investigate Cr(III) and Ni(II) ligands in alfalfa biomass

    SciTech Connect

    Tiemann, K.J.; Gardea-Torresdey, J.L.; Gamez, G.; Dokken, K.; Sias, S.; Renner, M.W.; Furenlid, L.R.

    1999-01-01

    Previously performed studies have shown that alfalfa shoot biomass can bind an appreciable amount of nickel(II) and chromium(III) ions from aqueous solution. Direct and indirect approaches were applied to study the possible mechanisms involved in metal binding by the alfalfa biomass. The direct approach involves investigations of the metal-bound alfalfa shoot biomass by X-ray absorption spectroscopic analysis (XANES and EXAFS). Results from these studies suggest that nickel(II) and chromium(III) binding mostly occurs through coordination with oxygen ligands. Indirect approaches consist of chemical modification of carboxylate groups that have been shown to play an important role in metal binding to the alfalfa biomass. An appreciable decrease in metal binding resulted after acidic methanol esterification of the biomass, indicating that carboxyl groups are entailed in the metal binding by the alfalfa biomass. In addition, base hydrolysis of the alfalfa biomass increased the binding of these metals, which further indicates that carboxyl groups play an important role in the binding of these metal ions from solution. Therefore, by combining two different techniques, their results indicate that carboxylate groups are the major ligands responsible for the binding of nickel(II) and chromium(III) by alfalfa biomass.

  6. X-ray absorption and photoelectron spectroscopy investigation of selenite reduction by FeII-bearing minerals.

    PubMed

    Scheinost, Andreas C; Kirsch, Regina; Banerjee, Dipanjan; Fernandez-Martinez, Alejandro; Zaenker, Harald; Funke, Harald; Charlet, Laurent

    2008-12-12

    The long-lived radionuclide 79Se is one of the elements of concern for the safe storage of high-level nuclear waste, since clay minerals in engineered barriers and natural aquifer sediments strongly adsorb cationic species, but to lesser extent anions like selenate (SeVIO4(2-)) and selenite (SeIVO3(2-)). Previous investigations have demonstrated, however, that SeIV and SeVI are reduced by surface-associated FeII, thereby forming insoluble Se0 and Fe selenides. Here we show that the mixed FeII/III (hydr)oxides green rust and magnetite, and the FeII sulfide mackinawite reduce selenite rapidly (< 1 day) to FeSe, while the slightly slower reduction by the FeII carbonate siderite produces elemental Se. In the case of mackinawite, both S(-II) and FeII surface atoms are oxidized at a ratio of one to four by producing a defective mackinawite surface. Comparison of these spectroscopic results with thermodynamic equilibrium modeling provides evidence that the nature of reduction end product in these FeII systems is controlled by the concentration of HSe(-); Se0 forms only at lower HSe(-) concentrations related to slower HSeO3(-) reduction kinetics. Even under thermodynamically unstable conditions, the initially formed Se solid phases may remain stable for longer periods since their low solubility prevents the dissolution required for a phase transformation into more stable solids. The reduction by Fe2+-montmorillonite is generally much slower and restricted to a pH range, where selenite is adsorbed (pH < 7), stressing the importance of a heterogeneous, surface-enhanced electron transfer reaction. Although the solids precipitated by the redox reaction are nanocrystalline, their solubility remains below 6.3 x 10(-8) M. No evidence for aqueous metal selenide colloids nor for Se sorption to colloidal phases was found. Since FeII phases like the ones investigated here should be ubiquitous in the near field of nuclear waste disposals as well as in the surrounding aquifers

  7. X-ray absorption and photoelectron spectroscopy investigation of selenite reduction by Fe II-bearing minerals

    NASA Astrophysics Data System (ADS)

    Scheinost, Andreas C.; Kirsch, Regina; Banerjee, Dipanjan; Fernandez-Martinez, Alejandro; Zaenker, Harald; Funke, Harald; Charlet, Laurent

    2008-12-01

    The long-lived radionuclide 79Se is one of the elements of concern for the safe storage of high-level nuclear waste, since clay minerals in engineered barriers and natural aquifer sediments strongly adsorb cationic species, but to lesser extent anions like selenate (Se VIO 42-) and selenite (Se IVO 32-). Previous investigations have demonstrated, however, that Se IV and Se VI are reduced by surface-associated Fe II, thereby forming insoluble Se 0 and Fe selenides. Here we show that the mixed Fe II/ III (hydr)oxides green rust and magnetite, and the Fe II sulfide mackinawite reduce selenite rapidly (< 1 day) to FeSe, while the slightly slower reduction by the Fe II carbonate siderite produces elemental Se. In the case of mackinawite, both S -II and Fe II surface atoms are oxidized at a ratio of one to four by producing a defective mackinawite surface. Comparison of these spectroscopic results with thermodynamic equilibrium modeling provides evidence that the nature of reduction end product in these Fe II systems is controlled by the concentration of HSe -; Se 0 forms only at lower HSe - concentrations related to slower HSeO 3- reduction kinetics. Even under thermodynamically unstable conditions, the initially formed Se solid phases may remain stable for longer periods since their low solubility prevents the dissolution required for a phase transformation into more stable solids. The reduction by Fe 2+-montmorillonite is generally much slower and restricted to a pH range, where selenite is adsorbed (pH < 7), stressing the importance of a heterogeneous, surface-enhanced electron transfer reaction. Although the solids precipitated by the redox reaction are nanocrystalline, their solubility remains below 6.3 × 10 - 8 M. No evidence for aqueous metal selenide colloids nor for Se sorption to colloidal phases was found. Since Fe II phases like the ones investigated here should be ubiquitous in the near field of nuclear waste disposals as well as in the surrounding

  8. Investigation of Quasi-periodic Variations in Hard X-Rays of Solar Flares. II. Further Investigation of Oscillating Magnetic Traps

    NASA Astrophysics Data System (ADS)

    Jakimiec, J.; Tomczak, M.

    2012-06-01

    In our recent paper (Jakimiec and Tomczak, Solar Physics 261, 233, 2010) we investigated quasi-periodic oscillations of hard X-rays during the impulsive phase of solar flares. We have come to the conclusion that they are caused by magnetosonic oscillations of magnetic traps within the volume of hard-X-ray (HXR) loop-top sources. In the present paper we investigate four flares that show clear quasi-periodic sequences of the HXR pulses. We also describe our phenomenological model of oscillating magnetic traps to show that it can explain the observed properties of the HXR oscillations. The main results are the following: i) Low-amplitude quasi-periodic oscillations occur before the impulsive phase of some flares. ii) The quasi-periodicity of the oscillations can change in some flares. We interpret this as being due to changes of the length of oscillating magnetic traps. iii) During the impulsive phase a significant part of the energy of accelerated (non-thermal) electrons is deposited within a HXR loop-top source. iv) The quick development of the impulsive phase is due to feedback between the pressure pulses by accelerated electrons and the amplitude of the magnetic-trap oscillation. v) The electron number density and magnetic field strength values obtained for the HXR loop-top sources in several flares fall within the limits of N≈(2 - 15)×1010 cm-3, B≈(45 - 130) gauss. These results show that the HXR quasi-periodic oscillations contain important information about the energy release in solar flares.

  9. Quasar x-ray spectra revisited

    NASA Technical Reports Server (NTRS)

    Shastri, P.; Wilkes, B. J.; Elvis, M.; Mcdowell, J.

    1992-01-01

    A sample of 45 quasars observed by the Imaging Proportional Counter (IPC) on the Einstein satellite is used to re-examine the relationship between the soft (0.2-3.5 keV) X-ray energy index and radio-loudness. We found the following: (1) the tendency for radio-loud quasars to have systematically flatter X-ray slopes than radio-quiet quasars (RQQ's) is confirmed with the soft X-ray excess having negligible effect; (2) there is a tendency for the flatness of the X-ray slope to correlate with radio core-dominance for radio-loud quasars, suggesting that a component of the X-ray emission is relativistically beamed; (3) for the RQQ's the soft X-ray slopes, with a mean of approximately 1.0, are consistent with the slopes found at higher energies (2-10 keV) although steeper than those observed for Seyfert 1 galaxies (also 2-10 keV) where the reflection model gives a good fit to the data; (4) the correlation of FeII emission line strength with X-ray energy index is confirmed for radio-quiet quasars using a subset of 18 quasars. The radio-loud quasars show no evidence for a correlation. This relation suggests a connection between the ionizing continuum and the line emission from the broad emission line region (BELR) of radio-quiet quasars, but in the opposite sense to that predicted by current photoionization models; and (5) the correlations of X-ray slope with radio core dominance and FeII equivalent width within the radio-loud and radio-quiet sub-classes respectively imply that the observed wide range of X-ray spectral slopes is real rather than due to the large measuring uncertainties for individual objects.

  10. X-ray in Zeta-Ori

    NASA Astrophysics Data System (ADS)

    López-García, M. A.; López-Santiago, J. L.; Albacete-Colombo, J. F.; De Castro, E.

    2013-05-01

    Nearby star-forming regions are ideal laboratories to study high-energy emission processes but they usually present high absorption what makes difficult to detect the stellar population inside the molecular complex. As young late-type stars show high X-ray emission and X-ray photons are little absorbed by interstellar material, X-ray dedicated surveys are an excellent tool to detect the low-mass stellar population in optically absorbed regions. In this work, we present a study of the star-forming region Zeta-Ori and its surroundings. We combine optical, infrared and X-ray data. Properties of the X-ray emiting plasma and infrared features of the young stellar objects detected in the XMM-Newton observation are determined. The southern part of the Orion B giant molecular cloud complex harbor other star forming regions, as NGC 2023 and NGC 2024, we use this regions to compare. We study the spectral energy distribution of X-ray sources. Combining these results with infrared, the X-ray sources are classified as class I, class II and class III objects. The X-ray spectrum and ligth curve of detected X-ray sources is analyzed to found flares. We use a extincion-independent index to select the stars with circumstellar disk, and study the relationship between the present of disk and the flare energy. The results are similar to others studies and we conclude that the coronal properties of class II and class III objects in this region do not differ significantly from each other and from stars of similar infrared class in the ONC.

  11. Analysis of the Central X-ray Source in DG Tau

    NASA Astrophysics Data System (ADS)

    Schneider, P. Christian; Schmitt, Jürgen H. M. M.

    As a stellar X-ray source DG Tau shows two rather unusual features: A resolved X-ray jet [2] and an X-ray spectrum best described by two thermal components with different absorbing column densities, a so called "two-absorber X-ray (TAX)" morphology [1, 2]. In an effort to understand the properties of the central X-ray source in DG Tau a detailed position analysis was carried out.

  12. Crystallization of Photosystem II for Time-Resolved Structural Studies Using an X-ray Free Electron Laser

    PubMed Central

    Coe, Jesse; Kupitz, Christopher; Basu, Shibom; Conrad, Chelsie E.; Roy-Chowdhury, Shatabdi; Fromme, Raimund; Fromme, Petra

    2015-01-01

    Photosystem II (PSII) is a membrane protein supercomplex that executes the initial reaction of photosynthesis in higher plants, algae, and cyanobacteria. It captures the light from the sun to catalyze a transmembrane charge separation. In a series of four charge separation events, utilizing the energy from four photons, PSII oxidizes two water molecules to obtain dioxygen, four protons, and four electrons. The light reactions of photosystems I and II (PSI and PSII) result in the formation of an electrochemical transmembrane proton gradient that is used for the production of ATP. Electrons that are subsequently transferred from PSI via the soluble protein ferredoxin to ferredoxin-NADP+ reductase that reduces NADP+ to NADPH. The products of photosynthesis and the elemental oxygen evolved sustain all higher life on Earth. All oxygen in the atmosphere is produced by the oxygen-evolving complex in PSII, a process that changed our planet from an anoxygenic to an oxygenic atmosphere 2.5 billion years ago. In this chapter, we provide recent insight into the mechanisms of this process and methods used in probing this question. PMID:25950978

  13. Crystallization of Photosystem II for Time-Resolved Structural Studies Using an X-ray Free Electron Laser.

    PubMed

    Coe, Jesse; Kupitz, Christopher; Basu, Shibom; Conrad, Chelsie E; Roy-Chowdhury, Shatabdi; Fromme, Raimund; Fromme, Petra

    2015-01-01

    Photosystem II (PSII) is a membrane protein supercomplex that executes the initial reaction of photosynthesis in higher plants, algae, and cyanobacteria. It captures the light from the sun to catalyze a transmembrane charge separation. In a series of four charge separation events, utilizing the energy from four photons, PSII oxidizes two water molecules to obtain dioxygen, four protons, and four electrons. The light reactions of photosystems I and II (PSI and PSII) result in the formation of an electrochemical transmembrane proton gradient that is used for the production of ATP. Electrons that are subsequently transferred from PSI via the soluble protein ferredoxin to ferredoxin-NADP(+) reductase that reduces NADP(+) to NADPH. The products of photosynthesis and the elemental oxygen evolved sustain all higher life on Earth. All oxygen in the atmosphere is produced by the oxygen-evolving complex in PSII, a process that changed our planet from an anoxygenic to an oxygenic atmosphere 2.5 billion years ago. In this chapter, we provide recent insight into the mechanisms of this process and methods used in probing this question.

  14. X-ray beam finder

    DOEpatents

    Gilbert, H.W.

    1983-06-16

    An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

  15. Trends in ultracool dwarf magnetism. II. The inverse correlation between X-ray activity and rotation as evidence for a bimodal dynamo

    SciTech Connect

    Cook, B. A.; Williams, P. K. G.; Berger, E.

    2014-04-10

    Observations of magnetic activity indicators in solar-type stars exhibit a relationship with rotation with an increase until a 'saturation' level and a moderate decrease in activity in the very fastest rotators ('supersaturation'). While X-ray data have suggested that this relationship is strongly violated in ultracool dwarfs (UCDs; spectral type ≳M7), the limited number of X-ray detections has prevented firm conclusions. In this paper, we analyze the X-ray activity-rotation relation in 38 UCDs. Our sample represents the largest catalog of X-ray active UCDs to date, including seven new and four previously unpublished Chandra observations presented in a companion paper. We identify a substantial number of rapidly rotating UCDs with X-ray activity extending two orders of magnitude below the expected saturation level and measure a 'supersaturation'-type anticorrelation between rotation and X-ray activity. The scatter in UCD X-ray activity at a fixed rotation is ∼3 times larger than that in earlier-type stars. We discuss several mechanisms that have been proposed to explain the data, including centrifugal stripping of the corona, and find them to be inconsistent with the observed trends. Instead, we suggest that an additional parameter correlated with both X-ray activity and rotation is responsible for the observed effects. Building on the results of Zeeman-Doppler imaging of UCD magnetic fields and our companion study of radio/X-ray flux ratios, we argue that this parameter is the magnetic field topology, and that the large scatter in UCD X-ray fluxes reflects the presence of two dynamo modes that produce distinct topologies.

  16. Trends in Ultracool Dwarf Magnetism. II. The Inverse Correlation Between X-Ray Activity and Rotation as Evidence for a Bimodal Dynamo

    NASA Astrophysics Data System (ADS)

    Cook, B. A.; Williams, P. K. G.; Berger, E.

    2014-04-01

    Observations of magnetic activity indicators in solar-type stars exhibit a relationship with rotation with an increase until a "saturation" level and a moderate decrease in activity in the very fastest rotators ("supersaturation"). While X-ray data have suggested that this relationship is strongly violated in ultracool dwarfs (UCDs; spectral type gsimM7), the limited number of X-ray detections has prevented firm conclusions. In this paper, we analyze the X-ray activity-rotation relation in 38 UCDs. Our sample represents the largest catalog of X-ray active UCDs to date, including seven new and four previously unpublished Chandra observations presented in a companion paper. We identify a substantial number of rapidly rotating UCDs with X-ray activity extending two orders of magnitude below the expected saturation level and measure a "supersaturation"-type anticorrelation between rotation and X-ray activity. The scatter in UCD X-ray activity at a fixed rotation is ~3 times larger than that in earlier-type stars. We discuss several mechanisms that have been proposed to explain the data, including centrifugal stripping of the corona, and find them to be inconsistent with the observed trends. Instead, we suggest that an additional parameter correlated with both X-ray activity and rotation is responsible for the observed effects. Building on the results of Zeeman-Doppler imaging of UCD magnetic fields and our companion study of radio/X-ray flux ratios, we argue that this parameter is the magnetic field topology, and that the large scatter in UCD X-ray fluxes reflects the presence of two dynamo modes that produce distinct topologies.

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

    NASA Astrophysics Data System (ADS)

    Reiter, Megan; Smith, Nathan; Bally, John

    2016-09-01

    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 Hα 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 Hα and allowing us to connect these jets with their embedded driving sources. The [Fe II] 1.64 μm/Hα flux ratio measured in the jets is ≳ 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 for 13 jets. The remaining jets emerge from opaque globules that obscure emission from the protostar. In many respects, the HH jets in Carina look like a scaled-up version of the jets driven by low-mass protostars. Altogether, these observations suggest that [Fe II] emission is a reliable tracer of dense, irradiated jets driven by intermediate-mass protostars. We argue that highly collimated outflows are common to more massive protostars, and that they suggest the outflow physics inferred for low-mass stars formation scales up to at least ˜8 M⊙.

  18. X-ray absorption study of the solvated Cu(II) ion: Transition from a solvated solid to the dissolved state

    SciTech Connect

    Carrado, K.A.; Wasserman, S.R. )

    1993-04-21

    X-ray absorption spectroscopy has often been used to examine the local environment around an absorbing cation in both the solid and the liquid state. In order to examine the properties of a transition-metal ion under conditions in which the degree of solvation can be regulated, the authors have placed cupric ions within a smectite clay. Smectite clays consist of negatively charged sheets of aluminosilicates which are separated by an interlayer whose thickness changes upon absorption of solvent. In the native clay used for these experiments, bentonite, the calcium was replaced with copper by stirring the clay in a 0.1 M aqueous solution of CuCl[sub 2]. For the experiments described here, Cu K-edge spectra were acquired at the National Synchrotron Light Source and Stanford Synchrotron Radiation Laboratory in both transmission and fluorescence modes. Four samples of Cu-bentonite powder, dried from water, methanol, ethanol, and ethylene glycol, were examined, as well as slurries of these samples in their respective solvents. The normalized X-ray absorption near edge (XANES) spectra are obtained for copper ion in the Cu-bentonite dried from methanol and for the Cu-clay as a slurry in the same solvent. The spectrum of the dry material clearly shows the electronic 1s-4p transition as a resolved shoulder on the absorption edge at 8986 eV. This transition, which is characteristic of a copper ion with square planar coordination, has broadened and almost disappeared in the slurry. The observed change suggests that as the solvent penetrates into the clay, some of the solvent molecules enter the coordination sphere of the copper(II) ion. The addition of two axial oxygen ligands shifts the coordination geometry of the Cu(II) from a square planar configuration to a distorted octahedron. There is an obvious change in the EXAFS data between the dry clay and the slurry which cannot be readily discerned by examination of the radial distributions alone. 23 refs., 2 figs., 1 tab.

  19. The X-ray polarimetric view of astrophysical black holes

    NASA Astrophysics Data System (ADS)

    Matt, Giorgio

    2016-07-01

    Our current X-ray view of astrophysical black holes is based on spectroscopic, imaging and timing analysis. In this talk I will discuss the importance of adding the polarimetric view. The geometry of the X-ray emitting corona, the distribution of accreting matter, the magnetic field in jets and even the space-time close to the event horizon can be probed by X-ray polarimetry. I will also discuss the observational perspectives in view of the X-ray polarimetric missions currently under study at NASA and ESA.

  20. Hard X-ray Emission Associated with High-Mass Star Formation in the Young Stellar Cluster NGC 2071

    NASA Astrophysics Data System (ADS)

    Skinner, S. L.; Audard, M.; Güdel, M.; Meyer, M. R.; Simmons, A. E.

    2008-06-01

    X-ray observations can penetrate high intervening extinction and are thus useful for probing physical conditions in young stellar clusters whose members are optically obscured. Such observations can provide information on magnetic processes at or near the surface of a formative (proto)-star and on mass-loss properties as diagnosed from X-ray emission associated with jets and shocked outflows. We present first results of X-ray observations of the embedded infrared cluster NGC 2071 in the Orion B molecular cloud with XMM-Newton. This cluster is of interest because it is one of the closest regions known to harbor high-mass protostars. We report the detection of hard X-ray emission from the dense central NGC 2071-IR subgroup which contains three massive protostars surrounded by ultracompact H II regions (IRS-1,2,3). The X-ray peak lies within ≈1'' of IRS-1, which drives one of the most powerful outflows known. The unusual X-ray spectrum shows a strong fluorescent Fe emission line at 6.4 keV superimposed on a hard continuum. This line is due to Fe I or weakly ionized Fe and likely originates in cold material near the protostar (i.e. a disk or envelope) that is irradiated by the hard central X-ray source.

  1. Industrial X-Ray Imaging

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In 1990, Lewis Research Center jointly sponsored a conference with the U.S. Air Force Wright Laboratory focused on high speed imaging. This conference, and early funding by Lewis Research Center, helped to spur work by Silicon Mountain Design, Inc. to break the performance barriers of imaging speed, resolution, and sensitivity through innovative technology. Later, under a Small Business Innovation Research contract with the Jet Propulsion Laboratory, the company designed a real-time image enhancing camera that yields superb, high quality images in 1/30th of a second while limiting distortion. The result is a rapidly available, enhanced image showing significantly greater detail compared to image processing executed on digital computers. Current applications include radiographic and pathology-based medicine, industrial imaging, x-ray inspection devices, and automated semiconductor inspection equipment.

  2. A zinc(II) quinolinone complex (Et3NH)[Zn(qui)Cl2]: Synthesis, X-ray structure, spectral properties and in vitro cytotoxicity

    NASA Astrophysics Data System (ADS)

    Buchtík, Roman; Nemec, Ivan; Trávníček, Zdeněk

    2014-02-01

    A new zinc(II) complex with 2-phenyl-3-hydroxy-4(1H)-quinolinone (Hqui) of the composition (Et3NH)[Zn(qui)Cl2] was prepared and characterized by elemental analysis, FT IR, 1D and 2D NMR, and fluorescence spectroscopy, mass spectrometry and single crystal X-ray analysis. The molecular structure is composed of the triethylammonium (Et3NH+) cations and tetrahedral [ZnII(qui)Cl2]- complex anions, in which the Zn(II) atoms are bidentate coordinated by one qui ligand through keto (OK) and phenolate (OP) oxygen atoms and by two chlorido ligands, thus forming the {O2Cl2} donor set, with Zn-OK = 1.9860(14) Å, Zn-OP 1.9961(14) Å and Zn-Cl = 2.2509(6) Å and 2.2266(6) Å. The complex cations are aligned into 1D supramolecular chains through the NH⋯Cl hydrogen bonding between the amine group of the quinolinone ligand and the chlorido ligand of the adjacent complex anion. The amine group from the Et3NH+ cations provides the NH⋯OP hydrogen bond with the phenolate oxygen atoms from the complex anion. Screening of in vitro cytotoxicity of the compound was studied on human osteosarcoma (HOS) and human breast adenocarcinoma (MCF7) cell lines, with IC50 > 50 μM. The fluorescence study showed that the complex exhibits a relatively high integral intensity (29%) as compared to the standard quinine sulfate, and 1.6-fold enhancement of emission with respect to free Hqui.

  3. Synthesis, characterization, and x-ray crystal structures of cyclam derivatives. 8. Thermodynamic and kinetic appraisal of lead(II) chelation by octadentate carbamoyl-armed macrocycles.

    PubMed

    Cuenot, François; Meyer, Michel; Espinosa, Enrique; Guilard, Roger

    2005-10-31

    En route toward the development of hybrid organic-inorganic extracting materials incorporating lead-selective chelators and their implementation in water purification processes, the lead(II) binding properties of three N-carbamoylmethyl-substituted 1,4,8,11-tetraazacyclotetradecanes (cyclams) have been fully investigated by spectroscopic (IR, UV-vis, MALDI-TOF MS, (1)H and (13)C NMR), X-ray crystallographic, potentiometric, and kinetic methods. Solution NMR studies revealed that the Pb(2+) ion is entrapped in a molecular cage constituted by the four macrocyclic nitrogen and four amidic oxygen atoms. Protonation and lead binding constants determined in aqueous solution were shown to be linearly dependent, so that all three derivatives possess a similar affinity at any pH value. Thermodynamic and kinetic parameters revealed the crucial role played by the intramolecular hydrogen bonds also evidenced in the crystal structure of the tetraacetamide derivative L(1), which involve the lone pair of each macrocyclic tertiary amine and one amidic hydrogen atom belonging to the appended arm. In contrast to L(1), the absence of such intramolecular interactions for N-(dimethyl)carbamoylmethyl- and N-(diethyl)carbamoylmethyl-substituted cyclams (L(2) and L(3), respectively) accounts for the 2-3 orders of magnitude enhancement of their proton and lead binding affinities. Stopped-flow kinetic measurements enabled unraveling the formation process of the three lead(II) complexes that proceeds in a single rate-limiting step according to the Eigen-Winkler mechanism, while the apparent rate constants were found to increase in the order L(3) < L(2) < L(1) as a consequence of the more acidic character of L(1). A common proton-assisted dissociation mechanism has been found for the three lead(II) complexes, which involves the rapid formation of a protonated, six-coordinate intermediate followed by either a unimolecular decomposition or a bimolecular attack of a second hydronium ion. PMID

  4. X-Ray Variability in M87

    NASA Technical Reports Server (NTRS)

    Harris, Daniel E.; Biretta, J. A.; Junor, W.

    2000-01-01

    We present the evidence for X-ray variability from the core and from knot A in the M87 jet based on data from two observations with the Einstein Observatory High Resolution Imager (HRI) and three observations with the ROSAT HRI. The core intensity showed a 16% increase in 17 months ('79-'80); a 12% increase in the 3 years '92 to '95; and a 17% drop in the last half of 1995. The intensity of knot A appears to have decreased by 16% between 92Jun and 95Dec. Although the core variability is consistent with general expectations for AGB nuclei, the changes in knot A provide constraints on the x-ray emission process and geometry. Thus we predict that the x-ray morphology of knot A will differ significantly from the radio and optical structure.

  5. Synthesis, characterization, single crystal X-ray determination, fluorescence and electrochemical studies of new dinuclear nickel(II) and oxovanadium(IV) complexes containing double Schiff base ligands.

    PubMed

    Shafaatian, Bita; Ozbakzaei, Zahra; Notash, Behrouz; Rezvani, S Ahmad

    2015-04-01

    A series of new bimetallic complexes of nickel(II) and vanadium(IV) have been synthesized by the reaction of the new double bidentate Schiff base ligands with nickel acetate and vanadyl acetylacetonate in 1:1 M ratio. In nickel and also vanadyl complexes the ligands were coordinated to the metals via the imine N and enolic O atoms. The complexes have been found to possess 1:1 metals to ligands stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The nickel and vanadyl complexes exhibited distorted square planar and square pyramidal coordination geometries, respectively. The emission spectra of the ligands and their complexes were studied in methanol. Electrochemical properties of the ligands and their metal complexes were also investigated in DMSO solvent at 150 mV s(-1) scan rate. The ligands and metal complexes showed both quasi-reversible and irreversible processes at this scan rate. The Schiff bases and their complexes have been characterized by FT-IR, 1H NMR, UV/Vis spectroscopies, elemental analysis and conductometry. The crystal structure of the nickel complex has been determined by single crystal X-ray diffraction.

  6. Biomimetic mono- and dinuclear Ni(I) and Ni(II) complexes studied by X-ray absorption and emission spectroscopy and quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Schuth, N.; Gehring, H.; Horn, B.; Holze, P.; Kositzki, R.; Schrapers, P.; Limberg, C.; Haumann, M.

    2016-05-01

    Five biomimetic mono- or dinuclear nickel complexes featuring Ni(I) or Ni(II) sites were studied by X-ray absorption and emission spectroscopy and DFT calculations. Ni K-edge XANES spectra and Kβ main and satellite emission lines were collected on powder samples. The pre-edge absorption transitions (core-to-valence excitation) and Kβ2,5 emission transitions (valence-to-core decay) were calculated using DFT (TPSSh/TZVP) on crystal structures. This yielded theoretical ctv and vtc spectra in near-quantitative agreement with the experiment, showing the adequacy of the DFT approach for electronic structure description, emphasizing the sensitivity of the XAS/XES spectra for ligation/redox changes at nickel, and revealing the configuration of unoccupied and occupied valence levels, as well as the spin-coupling modes in the dinuclear complexes. XAS/XES-DFT is valuable for molecular and electronic structure analysis of synthetic complexes and of nickel centers in H2 or COx converting metalloenzymes.

  7. Synthesis, spectral, X-ray single structure, DFT calculations and antimicrobial activities of [Co(II)X2 (dmphen)] (X = Br and SCN-)

    NASA Astrophysics Data System (ADS)

    Al-Noaimi, Mousa; Awwadi, Firas F.; Haddad, Salim F.; Talib, Wamidh H.; Jodeh, Shehdeh; Radi, Smaail; Ben Hadda, Taibi; Abdoh, Muneer; Naveen, S.; Lokanath, N. K.; Warad, Ismail

    2015-04-01

    Two tetrahedral mononuclear complexes with a general formula [CoX2(dmphen)](1-2) (where dmphen is 2,9-dimethyl-1,10-phenanthroline and 1 (X = Br), 2 (X = NCS)) have been synthesized. These complexes are characterized by elemental analysis, IR, UV-visible, TG/DTA and by X-ray diffraction. The calculated electrostatic potential surface of 2 has shown that the electrostatic potential values around sulfur atom is anistropically distributed; the potential values along C-S bond is less negative than the corresponding values in the π-region of S atom. This agrees with the observed geometrical arrangement of C-H⋯S-C hydrogen bonding interactions, the avg. of H⋯S-C angle is 81°. Antimicrobial properties of cobalt(II) complexes was also assessed. Cobalt complexes exhibited significant antibacterial activity against different gram negative and positive human pathogens. The absorption spectrum of these complexes in acetone was modeled by time-dependent density functional theory (TD-DFT).

  8. Comparison of the manganese oxygen-evolving complex in photosystem II of spinach and Synechococcus sp. with multinuclear manganese model compounds by X-ray absorption spectroscopy

    SciTech Connect

    DeRose, V.J.; Mukerji, I.; Latimer, M.J. ); Yachandra, V.K.; Klein, M.P. ); Sauer, K. Lawrence Berkeley Lab., CA )

    1994-06-15

    The evaluation of Mn X-ray absorption fine structure (EXAFS) studies on the oxygen-evolving complex (OEC) from photosystem II is described for preparations from both spinach and the cyanobacterium Synechococcus sp. poised in the S[sub 1] and S[sub 2] states. In addition to reproducing previous results suggesting the presence of bis([mu]-oxo)-bridged Mn centers in the OEC, a Fourier transform peak due to scatterers at an average distance of > 3 [angstrom] is detected in both types of preparation. In addition, subtle but reproducible changes are found in the relative amplitudes of the Fourier transform peaks due to mainly O ([approximately]1.8 [angstrom]) and Mn ([approximately] 2.7 [angstrom]) neighbors upon cryogenic advance from the S[sub 1] to the S[sub 2] state. Analysis of the peak due to scatterers at [approximately] 3 [angstrom] favors assignment to (per 4 Mn in the OEC) 1-2 heavy atom (Mn, Ca) scatterers at an average distance of 3.3-3.4 [angstrom]. The EXAFS data of several multinuclear Mn model compounds containing such scattering interactions are analyzed and compared with the data for the OEC. Structural models for the OEC are evaluated on the basis of these results. 40 refs., 9 figs., 5 tabs.

  9. X-Ray and Radio Studies of Black Hole X-Ray Transients During Outburst Decay

    NASA Technical Reports Server (NTRS)

    Tomsick, John A.

    2005-01-01

    Black hole (BH) and black hole candidate (BHC) transients are X-ray binary systems that typically undergo bright outbursts that last a couple months with recurrence times of years to decades. For this ADP project, we are studying BH/BHC systems during the decaying phases of their outbursts using the Rossi X-ray Taming Explorer (RXTE), the Chandra X-ray Observatory, and multi-wavelength facilities. These systems usually undergo state transitions as they decay, and our observations are designed to catch the state transitions. The specific goals of this proposal include: 1. To determine the evolution of the characteristic frequencies present in the power spectrum (such as quasi-periodic oscillations, QPOs) during state transitions in order to place constraints on the accretion geometry; 2. To contemporaneously measure X-ray spectral and timing properties along with flux measurements in the radio band to determine the relationship between the accretion disk and radio jets; 3. To extend our studies of X-ray properties of BHCs to very low accretion rates using RXTE and Chandra. The work performed under this proposal has been highly successful, allowing the PI to lead, direct, or assist in the preparation of 7 related publications in refereed journals and 6 other conference presentations or reports. These items are listed below, and the abstracts for the refereed publications have also been included. Especially notable results include our detailed measurements of the characteristic frequencies and spectral parameters of BH/BHCs after the transition to the hard state (see All A3, and A5) and at low flux levels (see A4). Our measurements provide one of the strongest lines of evidence to date that the inner edge of the optically thick accretion disk gradually recedes from the black hole at low flux levels. In addition, we have succeeded in obtaining excellent multi-wavelength coverage of a BH system as its compact jet turned on (see Al). Our results show, somewhat

  10. High-energy neutrino fluxes from AGN populations inferred from X-ray surveys

    NASA Astrophysics Data System (ADS)

    Jacobsen, Idunn B.; Wu, Kinwah; On, Alvina Y. L.; Saxton, Curtis J.

    2015-08-01

    High-energy neutrinos and photons are complementary messengers, probing violent astrophysical processes and structural evolution of the Universe. X-ray and neutrino observations jointly constrain conditions in active galactic nuclei (AGN) jets: their baryonic and leptonic contents, and particle production efficiency. Testing two standard neutrino production models for local source Cen A (Koers & Tinyakov and Becker & Biermann), we calculate the high-energy neutrino spectra of single AGN sources and derive the flux of high-energy neutrinos expected for the current epoch. Assuming that accretion determines both X-rays and particle creation, our parametric scaling relations predict neutrino yield in various AGN classes. We derive redshift-dependent number densities of each class, from Chandra and Swift/BAT X-ray luminosity functions (Silverman et al. and Ajello et al.). We integrate the neutrino spectrum expected from the cumulative history of AGN (correcting for cosmological and source effects, e.g. jet orientation and beaming). Both emission scenarios yield neutrino fluxes well above limits set by IceCube (by ˜4-106 × at 1 PeV, depending on the assumed jet models for neutrino production). This implies that: (i) Cen A might not be a typical neutrino source as commonly assumed; (ii) both neutrino production models overestimate the efficiency; (iii) neutrino luminosity scales with accretion power differently among AGN classes and hence does not follow X-ray luminosity universally; (iv) some AGN are neutrino-quiet (e.g. below a power threshold for neutrino production); (v) neutrino and X-ray emission have different duty cycles (e.g. jets alternate between baryonic and leptonic flows); or (vi) some combination of the above.

  11. Cd(II) and Zn(II) complexes of two new hexadentate Schiff base ligands derived from different aldehydes and ethanol amine; X-ray crystal structure, IR and NMR spectroscopy studies

    NASA Astrophysics Data System (ADS)

    Golbedaghi, Reza; Rezaeivala, Majid; Albeheshti, Leila

    2014-11-01

    Four new [Cd(H2L1)(NO3)]ClO4 (1), [Zn(H2L1)](ClO4)2 (2), [Cd(H2L2)(NO3)]ClO4 (3), and [Zn(H2L2)](ClO4)2 (4), complexes were prepared by the reaction of two new Schiff base ligands and Cd(II) and Zn(II) metal ions in equimolar ratios. The ligands H2L1 and H2L2 were synthesized by reaction of 2-[2-(2-formyl phenoxy)ethoxy]benzaldehyde and/or 2-[2-(3-formyl phenoxy)propoxy]benzaldehyde and ethanol amine and characterized by IR, 1H and 13C NMR spectroscopy. All complexes were characterized by IR, 1H and 13C NMR, COSY, and elemental analysis. Also, the complex 1 was characterized by X-ray in addition to the above methods. The X-ray crystal structure of compound 1 showed that all nitrogen and oxygen atoms of ligand (N2O4) and a molecule of nitrate with two donor oxygen atom have been coordinated to the metal ion and the Cd(II) ion is in an eight-coordinate environment that is best described as a distorted dodecahedron geometry.

  12. Filament Eruptions, Jets, and Space Weather

    NASA Technical Reports Server (NTRS)

    Moore, Ronald; Sterling, Alphonse; Robe, Nick; Falconer, David; Cirtain, Jonathan

    2013-01-01

    Previously, from chromospheric H alpha and coronal X-ray movies of the Sun's polar coronal holes, it was found that nearly all coronal jets (greater than 90%) are one or the other of two roughly equally common different kinds, different in how they erupt: standard jets and blowout jets (Yamauchi et al 2004, Apl, 605, 5ll: Moore et all 2010, Apj, 720, 757). Here, from inspection of SDO/AIA He II 304 A movies of 54 polar x-ray jets observed in Hinode/XRT movies, we report, as Moore et al (2010) anticipated, that (1) most standard x-ray jets (greater than 80%) show no ejected plasma that is cool enough (T is less than or approximately 10(exp 5K) to be seen in the He II 304 A movies; (2) nearly all blownout X-ray jets (greater than 90%) show obvious ejection of such cool plasma; (3) whereas when cool plasma is ejected in standard X-ray jets, it shows no lateral expansion, the cool plasma ejected in blowout X-ray jets shows strong lateral expansion; and (4) in many blowout X-ray jets, the cool plasma ejection displays the erupting-magnetic-rope form of clasic filament eruptions and is thereby seen to be a miniature filament eruption. The XRT movies also showed most blowout X-ray jets to be larger and brighter, and hence to apparently have more energy, than most standard X-ray jets. These observations (1) confirm the dichotomy of coronal jets, (2) agree with the Shibata model for standard jets, and (3) support the conclusion of Moore et al (2010) that in blowout jets the magnetic-arch base of the jet erupts in the manner of the much larger magnetic arcades in which the core field, the field rooted along the arcade's polarity inversion line, is sheared and twisted (sigmoid), often carries a cool-plasma filament, and erupts to blowout the arcade, producing a CME. From Hinode/SOT Ca II movies of the polar limb, Sterling et al (2010, ApJ, 714, L1) found that chromospheric Type-II spicules show a dichotomy of eruption dynamics similar to that found here for the cool

  13. X-ray lithography masking

    NASA Technical Reports Server (NTRS)

    Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

    1998-01-01

    X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

  14. X-ray characterization and magnetic properties of dioxygen-bridged Cu(II) and Mn(III) Schiff base complexes.

    PubMed

    Yahsi, Yasemin

    2016-07-01

    The coordination chemistry of multinuclear metal compounds is important because of their relevance to the multi-metal active sites of various metalloproteins and metalloenzymes. Multinuclear Cu(II) and Mn(III) compounds are of interest due to their various properties in the fields of coordination chemistry, inorganic biochemistry, catalysis, and optical and magnetic materials. Oxygen-bridged binuclear Mn(III) complexes generally exhibit antiferromagnetic interactions and a few examples of ferromagnetic interactions have also been reported. Binuclear Cu(II) complexes are important due to the fact that they provide examples of the simplest case of magnetic interaction involving only two unpaired electrons. Two novel dioxygen-bridged copper(II) and manganese(III) Schiff base complexes, namely bis(μ-4-bromo-2-{[(3-oxidopropyl)imino]methyl}phenolato)dicopper(II), [Cu2(C10H10BrNO2)2], (1), and bis(diaqua{4,4'-dichloro-2,2'-[(1,1-dimethylethane-1,2-diyl)bis(nitrilomethanylylidene)]diphenolato}manganese(III)) bis{μ-4,4'-dichloro-2,2'-[(1,1-dimethylethane-1,2-diyl)bis(nitrilomethanylylidene)]diphenolato}bis[aquamanganese(III)] tetrakis(perchlorate) ethanol disolvate, [Mn(C18H16Cl2N2O2)(H2O)2]2[Mn2(C18H16Cl2N2O2)2(H2O)2](ClO4)4·2C2H5OH, (2), have been synthesized and single-crystal X-ray diffraction has been used to analyze their crystal structures. The structure analyses of (1) and (2) show that each Cu(II) atom is four-coordinated, with long weak Cu...O interactions of 2.8631 (13) Å linking the dinuclear halves of the centrosymmetric tetranucelar molecules, while each Mn(III) atom is six-coordinated. The shortest intra- and intermolecular nonbonding Mn...Mn separations are 3.3277 (16) and 5.1763 (19) Å for (2), while the Cu...Cu separations are 3.0237 (3) and 3.4846 (3) Å for (1). The magnetic susceptibilities of (1) and (2) in the solid state were measured in the temperature range 2-300 K and reveal the presence of antiferromagnetic spin

  15. Synthesis, X-ray structure and in vitro cytotoxicity studies of Cu(I/II) complexes of thiosemicarbazone: special emphasis on their interactions with DNA.

    PubMed

    Saswati; Chakraborty, Ayon; Dash, Subhashree P; Panda, Alok K; Acharyya, Rama; Biswas, Ashis; Mukhopadhyay, Subhadip; Bhutia, Sujit K; Crochet, Aurélien; Patil, Yogesh P; Nethaji, M; Dinda, Rupam

    2015-04-01

    4-(p-X-phenyl)thiosemicarbazone of napthaldehyde {where X = Cl (HL¹) and X = Br (HL²)}, thiosemicarbazone of quinoline-2-carbaldehyde (HL³) and 4-(p-fluorophenyl)thiosemicarbazone of salicylaldehyde (H₂L⁴) and their copper(I) {[Cu(HL¹)(PPh₃)₂Br]·CH₃CN (1) and [Cu(HL²)(PPh₃)₂Cl]·DMSO (2)} and copper(II) {[(Cu₂L³₂Cl)₂(μ-Cl)₂]·2H₂O (3) and [Cu(L⁴)(Py)] (4)} complexes are reported herein. The synthesized ligands and their copper complexes were successfully characterized by elemental analysis, cyclic voltammetry, NMR, ESI-MS, IR and UV-Vis spectroscopy. Molecular structures of all the Cu(I) and Cu(II) complexes have been determined by X-ray crystallography. All the complexes (1-4) were tested for their ability to exhibit DNA-binding and -cleavage activity. The complexes effectively interact with CT-DNA possibly by groove binding mode, with binding constants ranging from 10⁴ to 10⁵ M⁻¹. Among the complexes, 3 shows the highest chemical (60%) as well as photo-induced (80%) DNA cleavage activity against pUC19 DNA. Finally, the in vitro antiproliferative activity of all the complexes was assayed against the HeLa cell line. Some of the complexes have proved to be as active as the clinical referred drugs, and the greater potency of 3 may be correlated with its aqueous solubility and the presence of the quinonoidal group in the thiosemicarbazone ligand coordinated to the metal.

  16. Copper(II) cyanido-bridged bimetallic nitroprusside-based complexes: Syntheses, X-ray structures, magnetic properties, {sup 57}Fe Moessbauer spectroscopy and thermal studies

    SciTech Connect

    Travnicek, Zdenek; Herchel, Radovan; Mikulik, Jiri; Zboril, Radek

    2010-05-15

    Three heterobimetallic cyanido-bridged copper(II) nitroprusside-based complexes of the compositions [Cu(tet)Fe(CN){sub 5}NO].H{sub 2}O (1), where tet=N,N'-bis(3-aminopropyl)ethylenediamine, [Cu(hto)Fe(CN){sub 5}NO].2H{sub 2}O (2), where hto=1,3,6,9,11,14-hexaazatricyclo[12.2.1.1{sup 6,9}]octadecane and [Cu(nme){sub 2}Fe(CN){sub 5}NO].H{sub 2}O (3), where nme=N-methylethylenediamine, were synthesized and characterized by elemental analyses, {sup 57}Fe Moessbauer and FTIR spectroscopies, thermal analysis, magnetic measurements and single-crystal X-ray analysis. The products of thermal degradation processes of 2 and 3 were studied by XRD, {sup 57}Fe Moessbauer spectroscopy, SEM and EDS, and they were identified as mixtures of CuFe{sub 2}O{sub 4} and CuO. - Three heterobimetallic cyano-bridged copper(II) nitroprusside-based complexes of the general compositions of [Cu(L)Fe(CN){sub 5}NO].xH{sub 2}O, where L=N,N'-bis(3-aminopropyl)ethylenediamine (complex 1), 1,3,6,9,11,14-hexaazatricyclo[12.2.1.1{sup 6,9}]-octadecane (complex 2) and N-methylethylenediamine (complex 3), were synthesized, and fully structurally and magnetically characterized. SEM, EDS, XRD and {sup 57}Fe Moessbauer experiments were used for characterization of thermal decomposition products of complexes 2 and 3.

  17. X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2004-01-01

    The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare X R S microcalorimeter spectrometer at the EBIT-I facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolution. The X R S microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high energy resolution by operating at 0.06K and by carefully controlling the heat capacity and thermal conductance. The XRS/EBIT instrument has 32 pixels in a square geometry and achieves an energy resolution of 6 eV at 6 keV, with a bandpass from 0.1 to 12 keV (or more at higher operating temperature). The instrument allows detailed studies of the x-ray line emission of laboratory plasmas. The XRS/EBIT also provides an extensive calibration "library" for the Astro-E2 observatory.

  18. X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    Dr. S. N. Zhang has lead a seven member group (Dr. Yuxin Feng, Mr. XuejunSun, Mr. Yongzhong Chen, Mr. Jun Lin, Mr. Yangsen Yao, and Ms. Xiaoling Zhang). This group has carried out the following activities: continued data analysis from space astrophysical missions CGRO, RXTE, ASCA and Chandra. Significant scientific results have been produced as results of their work. They discovered the three-layered accretion disk structure around black holes in X-ray binaries; their paper on this discovery is to appear in the prestigious Science magazine. They have also developed a new method for energy spectral analysis of black hole X-ray binaries; four papers on this topics were presented at the most recent Atlanta AAS meeting. They have also carried Monte-Carlo simulations of X-ray detectors, in support to the hardware development efforts at Marshall Space Flight Center (MSFC). These computation-intensive simulations have been carried out entirely on the computers at UAH. They have also carried out extensive simulations for astrophysical applications, taking advantage of the Monte-Carlo simulation codes developed previously at MSFC and further improved at UAH for detector simulations. One refereed paper and one contribution to conference proceedings have been resulted from this effort.

  19. Monitoring X-Ray Emission from X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, Philip

    1998-01-01

    The goal of this investigation was to use the All-Sky Monitor on the Rossi X-Ray Timing Explorer (RXTE) in combination with the Burst and Transient Source Experiment on the Compton Gamma-Ray Observatory to simultaneously measure the x-ray (2-12 keV) and hard x-ray (20-100 keV) emission from x-ray bursters. The investigation was successful. We made the first simultaneous measurement of hard and soft x-ray emission and found a strong anticorrelation of hard and soft x-ray emission from the X-Ray Burster 4U 0614+091. The monitoring performed under this investigation was also important in triggering target of opportunity observations of x-ray bursters made under the investigation hard x-ray emission of x-ray bursters approved for RXTE cycles 1 and 2. These observations lead to a number of papers on high-frequency quasi-periodic oscillations and on hard x-ray emission from the x-ray bursters 4U 0614+091 and 4U 1705-44.

  20. Mutation induction in haploid yeast after split-dose radiation exposure. II. Combination of UV-irradiation and X-rays.

    PubMed

    Keller, B; Zölzer, F; Kiefer, J

    2004-01-01

    Split-dose protocols can be used to investigate the kinetics of recovery from radiation damage and to elucidate the mechanisms of cell inactivation and mutation induction. In this study, a haploid strain of the yeast, Saccharomyces cerevisiae, wild-type with regard to radiation sensitivity, was irradiated with 254-nm ultraviolet (UV) light and then exposed to X-rays after incubation for 0-6 hr. The cells were incubated either on nutrient medium or salt agar between the treatments. Loss of reproductive ability and mutation to canavanine resistance were measured. When the X-ray exposure immediately followed UV-irradiation, the X-ray survival curves had the same slope irrespective of the pretreatment, while the X-ray mutation induction curves were changed from linear to linear quadratic with increasing UV fluence. Incubations up to about 3 hr on nutrient medium between the treatments led to synergism with respect to cell inactivation and antagonism with respect to mutation, but after 4-6 hr the two treatments acted independently. Incubation on salt agar did not cause any change in the survival curves, but there was a strong suppression of X-ray-induced mutation with increasing UV fluence. On the basis of these results, we suggest that mutation after combined UV and X-ray exposure is affected not only by the induction and suppression of DNA repair processes, but also by radiation-induced modifications of cell-cycle progression and changes in the expression of the mutant phenotype.

  1. Effects of X-ray irradiation on natural killer (NK) cell system. II. Increased sensitivity to natural killer cytotoxic factor (NKCF)

    SciTech Connect

    Uchida, A.; Mizutani, Y.; Nagamuta, M.; Ikenaga, M. )

    1989-01-01

    Irradiation with low-doses of X-rays of tumor cells elevated their susceptibility to lysis by natural killer (NK) cells in an accompanying paper. Cytotoxicity assays conducted at the single cell level revealed that X-ray irradiation of K562 cells did not affect the number of effector-target conjugates but increased the frequency of dead conjugated target cells. During interaction with K562 cells large granular lymphocytes released a soluble cytotoxic factor (NKCF) that killed the target cells. X-ray irradiation did not affect the NKCF stimulatory ability of K562 cells, while it elevated their sensitivity to the lytic effect of NKCF. In contrast to X-rays, exposure to ultraviolet (UV) radiation of K562 cells did not elevate their NK sensitivity but rather reduced it. Treatment with mitomycin C produced no effect on NK sensitivity. These results indicate that X-ray irradiation elevates the target sensitivity to NKCF, which may be involved in the increased NK sensitivity, and that the X-ray effect may be different from that of UV radiation or DNA synthesis inhibition.

  2. Synchrotron X-ray tests of an L-shaped laterally graded multilayer mirror for the analyzer system of the ultra-high-resolution IXS spectrometer at NSLS-II.

    PubMed

    Honnicke, Marcelo G; Keister, Jeffrey W; Conley, Raymond; Kaznatcheev, Konstantine; Takacs, Peter Z; Coburn, David Scott; Reffi, Leo; Cai, Yong Q

    2011-11-01

    Characterization and testing of an L-shaped laterally graded multilayer mirror are presented. This mirror is designed as a two-dimensional collimating optics for the analyzer system of the ultra-high-resolution inelastic X-ray scattering (IXS) spectrometer at National Synchrotron Light Source II (NSLS-II). The characterization includes point-to-point reflectivity measurements, lattice parameter determination and mirror metrology (figure, slope error and roughness). The synchrotron X-ray test of the mirror was carried out reversely as a focusing device. The results show that the L-shaped laterally graded multilayer mirror is suitable to be used, with high efficiency, for the analyzer system of the IXS spectrometer at NSLS-II.

  3. Fluctuation X-Ray Scattering

    SciTech Connect

    Saldin, PI: D. K.; Co-I's: J. C. H. Spence and P. Fromme

    2013-01-25

    The work supported by the grant was aimed at developing novel methods of finding the structures of biomolecules using x-rays from novel sources such as the x-ray free electron laser and modern synchrotrons

  4. Dual X-ray absorptiometry

    NASA Astrophysics Data System (ADS)

    Altman, Albert; Aaron, Ronald

    2012-07-01

    Dual X-ray absorptiometry is widely used in analyzing body composition and imaging. Both the method and its limitations are related to the Compton and photoelectric contributions to the X-ray attenuation coefficients of materials.

  5. Tunable X-ray source

    DOEpatents

    Boyce, James R.

    2011-02-08

    A method for the production of X-ray bunches tunable in both time and energy level by generating multiple photon, X-ray, beams through the use of Thomson scattering. The method of the present invention simultaneously produces two X-ray pulses that are tunable in energy and/or time.

  6. X-ray Crystallography Facility

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Edward Snell, a National Research Council research fellow at NASA's Marshall Space Flight Center (MSFC), prepares a protein crystal for analysis by x-ray crystallography as part of NASA's structural biology program. The small, individual crystals are bombarded with x-rays to produce diffraction patterns, a map of the intensity of the x-rays as they reflect through the crystal.

  7. Batch crystallization of rhodopsin for structural dynamics using an X-ray free-electron laser

    SciTech Connect

    Wu, Wenting; Nogly, Przemyslaw; Rheinberger, Jan; Kick, Leonhard M.; Gati, Cornelius; Nelson, Garrett; Deupi, Xavier; Standfuss, Jörg; Schertler, Gebhard; Panneels, Valérie

    2015-06-27

    A new batch preparation method is presented for high-density micrometre-sized crystals of the G protein-coupled receptor rhodopsin for use in time-resolved serial femtosecond crystallography at an X-ray free-electron laser using a liquid jet. Rhodopsin is a membrane protein from the G protein-coupled receptor family. Together with its ligand retinal, it forms the visual pigment responsible for night vision. In order to perform ultrafast dynamics studies, a time-resolved serial femtosecond crystallography method is required owing to the nonreversible activation of rhodopsin. In such an approach, microcrystals in suspension are delivered into the X-ray pulses of an X-ray free-electron laser (XFEL) after a precise photoactivation delay. Here, a millilitre batch production of high-density microcrystals was developed by four methodical conversion steps starting from known vapour-diffusion crystallization protocols: (i) screening the low-salt crystallization conditions preferred for serial crystallography by vapour diffusion, (ii) optimization of batch crystallization, (iii) testing the crystal size and quality using second-harmonic generation (SHG) imaging and X-ray powder diffraction and (iv) production of millilitres of rhodopsin crystal suspension in batches for serial crystallography tests; these crystals diffracted at an XFEL at the Linac Coherent Light Source using a liquid-jet setup.

  8. Tris(2,2'-azobispyridine) complexes of copper(II): X-ray structures, reactivities, and the radical nonradical bis(ligand) analogues.

    PubMed

    Maity, Suvendu; Kundu, Suman; Weyhermüller, Thomas; Ghosh, Prasanta

    2015-02-16

    Tris(abpy) complexes of types mer-[Cu(II)(abpy)3][PF6]2 (mer-1(2+)[PF6(–)]2) and ctc-[Cu(II)(abpy)2(bpy)][PF6]2 (ctc-2(2+)[PF6(–)]2) were successfully isolated and characterized by spectra and single-crystal X-ray structure determinations (abpy = 2,2′-azobispyridine; bpy = 2,2′-bipyridine). Reactions of mer-1(2+) and ctc-2(2+) ions with catechol, o-aminophenol, p-phenylenediamine, and diphenylamine (Ph–NH–Ph) in 2:1 molar ratio afford [CuI(abpy)2](+) (3(+)) and corresponding quinone derivatives. The similar reactions of [Cu(II)(bpy)3](2+) and [Cu(II)(phen)3](2+) with these substrates yielding [Cu(I)(bpy)2](+) and [Cu(I)(phen)2](+) imply that these complexes undergo reduction-induced ligand dissociation reactions (phen = 1,10-phenanthroline). The average −N═N– lengths in mer-1(2+)[PF6(–)]2 and ctc-2(2+)[PF6(–)]2 are 1.248(4), while that in 3(+)[PF6(–)]·2CH2Cl2 is relatively longer, 1.275(2) Å, due to dCu → πazo* back bonding. In cyclic voltammetry, mer-1(2+) exhibits one quasi-reversible wave at −0.42 V due to Cu(II)/Cu(I) and abpy/abpy(•–) couples and two reversible waves at −0.90 and −1.28 V due to abpy/abpy(•–) couple, while those of ctc-2(2+) ion appear at −0.44, −0.86, and −1.10 V versus Fc(+)/Fc couple. The anodic 3(2+)/3(+) and the cathodic 3(+)/3 redox waves at +0.33 and −0.40 V are reversible. The electron paramagnetic resonance spectra and density functional theory (DFT) calculations authenticated the existence of abpy anion radical (abpy(•–)) in 3, which is defined as a hybrid state of [Cu(I)(abpy(0.5•–))(abpy(0.5•–))] and [Cu(II)(abpy(•–))(abpy(•–))] states. 3(2+) ion is a neutral abpy complex of copper(II) of type [Cu(II)(abpy)2](2+). 3 exhibits a near-IR absorption band at 2400–3000 nm because of the intervalence ligand-to-ligand charge transfer, elucidated by time-dependent DFT calculations in CH2Cl2.

  9. Tris(2,2'-azobispyridine) complexes of copper(II): X-ray structures, reactivities, and the radical nonradical bis(ligand) analogues.

    PubMed

    Maity, Suvendu; Kundu, Suman; Weyhermüller, Thomas; Ghosh, Prasanta

    2015-02-16

    Tris(abpy) complexes of types mer-[Cu(II)(abpy)3][PF6]2 (mer-1(2+)[PF6(–)]2) and ctc-[Cu(II)(abpy)2(bpy)][PF6]2 (ctc-2(2+)[PF6(–)]2) were successfully isolated and characterized by spectra and single-crystal X-ray structure determinations (abpy = 2,2′-azobispyridine; bpy = 2,2′-bipyridine). Reactions of mer-1(2+) and ctc-2(2+) ions with catechol, o-aminophenol, p-phenylenediamine, and diphenylamine (Ph–NH–Ph) in 2:1 molar ratio afford [CuI(abpy)2](+) (3(+)) and corresponding quinone derivatives. The similar reactions of [Cu(II)(bpy)3](2+) and [Cu(II)(phen)3](2+) with these substrates yielding [Cu(I)(bpy)2](+) and [Cu(I)(phen)2](+) imply that these complexes undergo reduction-induced ligand dissociation reactions (phen = 1,10-phenanthroline). The average −N═N– lengths in mer-1(2+)[PF6(–)]2 and ctc-2(2+)[PF6(–)]2 are 1.248(4), while that in 3(+)[PF6(–)]·2CH2Cl2 is relatively longer, 1.275(2) Å, due to dCu → πazo* back bonding. In cyclic voltammetry, mer-1(2+) exhibits one quasi-reversible wave at −0.42 V due to Cu(II)/Cu(I) and abpy/abpy(•–) couples and two reversible waves at −0.90 and −1.28 V due to abpy/abpy(•–) couple, while those of ctc-2(2+) ion appear at −0.44, −0.86, and −1.10 V versus Fc(+)/Fc couple. The anodic 3(2+)/3(+) and the cathodic 3(+)/3 redox waves at +0.33 and −0.40 V are reversible. The electron paramagnetic resonance spectra and density functional theory (DFT) calculations authenticated the existence of abpy anion radical (abpy(•–)) in 3, which is defined as a hybrid state of [Cu(I)(abpy(0.5•–))(abpy(0.5•–))] and [Cu(II)(abpy(•–))(abpy(•–))] states. 3(2+) ion is a neutral abpy complex of copper(II) of type [Cu(II)(abpy)2](2+). 3 exhibits a near-IR absorption band at 2400–3000 nm because of the intervalence ligand-to-ligand charge transfer, elucidated by time-dependent DFT calculations in CH2Cl2. PMID:25650719

  10. X-ray satellite

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An overview of the second quarter 1985 development of the X-ray satellite project is presented. It is shown that the project is proceeding according to plan and that the projected launch date of September 9, 1987 is on schedule. An overview of the work completed and underway on the systems, subsystems, payload, assembly, ground equipment and interfaces is presented. Problem areas shown include cost increases in the area of focal instrumentation, the star sensor light scattering requirements, and postponements in the data transmission subsystems.

  11. SMM x ray polychromator

    NASA Technical Reports Server (NTRS)

    Saba, J. L. R.

    1993-01-01

    The objective of the X-ray Polychromator (XRP) experiment was to study the physical properties of solar flare plasma and its relation to the parent active region to understand better the flare mechanism and related solar activity. Observations were made to determine the temperature, density, and dynamic structure of the pre-flare and flare plasma as a function of wavelength, space and time, the extent to which the flare plasma departs from thermal equilibrium, and the variation of this departure with time. The experiment also determines the temperature and density structure of active regions and flare-induced changes in the regions.

  12. Correlated X-ray and optical variability in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    O'Brien, K.; Horne, K.

    In X-ray binaries much of the optical/UV emission arises from X-rays reprocessed by material in the accretion disk, stream and the companion star. The resulting optical variability will be delayed in time with respect to the X-ray variability depending on the position of the reprocessing regions in the binary system. By deconvolving the X-ray and optical variability we can determine a range of time-delays present in the system. This time-delay transfer function can be used to echo-map the geometry of the reprocessing regions in the binary system. We present results from our echo-mapping campaign using X-ray lightcurves from RXTE, simultaneous with high time resolution optical and UV observations. In the SXT, GRO J1655-40, using RXTE and HST shortly after the 1996 outburst, we find evidence for reprocessing in the outer regions of a thick accretion disk. In the Z-source Cygnus X-2, using RXTE and Keck II, we find an anti-correlation of the X-ray and optical variability on the timescale of hours, with superimposed correlated X-ray and optical flaring.

  13. Novel zinc(II) and copper(II) complexes of a Mannich base derived from lawsone: Synthesis, single crystal X-ray analysis, ab initio density functional theory calculations and vibrational analysis.

    PubMed

    Neves, Amanda P; Vargas, Maria D; Téllez Soto, Claudio A; Ramos, Joanna M; Visentin, Lorenzo do C; Pinheiro, Carlos B; Mangrich, Antônio S; de Rezende, Edivaltrys I P

    2012-08-01

    Zinc(II) and copper(II) complexes of a tridentate Mannich base L1 derived from 2-hydroxy-1,4-naphthoquinone, pyridinecarboxyaldehyde and 2-aminomethylpyridine, [ZnL1Cl(2)]·H(2)O 1 and [CuL1Cl(2)]·2H(2)O 2, have been synthesized and fully characterized. The structure of complex 1 has been elucidated by a single crystal X-ray diffraction study: the zinc atom is pentacoordinate and the coordination geometry is a distorted square base pyramid, with a geometric structural parameter τ equal to 0.149. Vibrational spectroscopy and ab initio DFT calculations of both compounds have confirmed that the two complexes exhibit similar structures. Full assignment of the vibrational spectra was also supported by careful analysis of the distorted geometries generated by the normal modes. PMID:22513170

  14. Soft x-ray lasers

    SciTech Connect

    Matthews, D.L.; Rosen, M.D.

    1988-12-01

    One of the elusive dreams of laser physicists has been the development of an x-ray laser. After 25 years of waiting, the x-ray laser has at last entered the scientific scene, although those now in operation are still laboratory prototypes. They produce soft x rays down to about five nanometers. X-ray lasers retain the usual characteristics of their optical counterparts: a very tight beam, spatial and temporal coherence, and extreme brightness. Present x-ray lasers are nearly 100 times brighter that the next most powerful x-ray source in the world: the electron synchrotron. Although Lawrence Livermore National Laboratory (LLNL) is widely known for its hard-x-ray laser program which has potential applications in the Strategic Defense Initiative, the soft x-ray lasers have no direct military applications. These lasers, and the scientific tools that result from their development, may one day have a place in the design and diagnosis of both laser fusion and hard x-ray lasers. The soft x-ray lasers now in operation at the LLNL have shown great promise but are still in the primitive state. Once x-ray lasers become reliable, efficient, and economical, they will have several important applications. Chief among them might be the creation of holograms of microscopic biological structures too small to be investigated with visible light. 5 figs.

  15. Note: development of a compact x-ray particle image velocimetry for measuring opaque flows. II. Three-dimensional velocity field reconstruction.

    PubMed

    Jung, Sung Yong; Lee, Sang Joon

    2012-04-01

    An x-ray particle image velocimetry (PIV) system using a cone-beam type x-ray was developed. The field of view and the spatial resolution are 36 × 24.05 mm(2) and 20 μm, respectively. The three-dimensional velocity field was reconstructed by adopting the least squares minimum residue and simultaneous multiplicative algebraic reconstruction techniques. According to a simulation study with synthetic images, the reconstructions were acceptable with 7 projections and 50 iterations. The reconstructed and supplied flow rates differed by only about 6.49% in experimental verification. The x-ray tomographic PIV system would be useful for 3D velocity field information of opaque flows.

  16. Note: Development of a compact x-ray particle image velocimetry for measuring opaque flows. II. Three-dimensional velocity field reconstruction

    NASA Astrophysics Data System (ADS)

    Jung, Sung Yong; Lee, Sang Joon

    2012-04-01

    An x-ray particle image velocimetry (PIV) system using a cone-beam type x-ray was developed. The field of view and the spatial resolution are 36 × 24.05 mm2 and 20 μm, respectively. The three-dimensional velocity field was reconstructed by adopting the least squares minimum residue and simultaneous multiplicative algebraic reconstruction techniques. According to a simulation study with synthetic images, the reconstructions were acceptable with 7 projections and 50 iterations. The reconstructed and supplied flow rates differed by only about 6.49% in experimental verification. The x-ray tomographic PIV system would be useful for 3D velocity field information of opaque flows.

  17. X-ray lithography source

    DOEpatents

    Piestrup, M.A.; Boyers, D.G.; Pincus, C.

    1991-12-31

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits is disclosed. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and eliminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an excellent moderate-priced X-ray source for lithography. 26 figures.

  18. X-ray lithography source

    DOEpatents

    Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary

    1991-01-01

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.

  19. Monitoring X-Ray Emission from X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.; Kaaret, Philip

    1999-01-01

    The scientific goal of this project was to monitor a selected sample of x-ray bursters using data from the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer together with data from the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory to study the long-term temporal evolution of these sources in the x-ray and hard x-ray bands. The project was closely related to "Long-Term Hard X-Ray Monitoring of X-Ray Bursters", NASA project NAG5-3891, and and "Hard x-ray emission of x-ray bursters", NASA project NAG5-4633, and shares publications in common with both of these. The project involved preparation of software for use in monitoring and then the actual monitoring itself. These efforts have lead to results directly from the ASM data and also from Target of Opportunity Observations (TOO) made with the Rossi X-Ray Timing Explorer based on detection of transient hard x-ray outbursts with the ASM and BATSE.

  20. Soft x-ray laser microscope

    SciTech Connect

    Suckewer, P.I.

    1990-10-01

    The program consisted of two phases (Phase I and Phase II). The goal of the Phase I (first year program) was to design and construct the Soft X-ray Laser Contact Microscope. Such microscope was constructed and adapted to PPL's 18.2nm soft X-ray Laser (SXL), which in turn was modified and prepared for microscopy experiments. Investigation of the photoresist response to 18.2nm laser radiation and transmissivity of 0.1m thick silicion-nitride (Si[sub 3]N[sub 4]) windows were important initial works. The goal of the first year of Phase II was to construct X-ray contact microscope in combination with existing optical phase microscope, already used by biologists. In the second year of Phase II study of dehydrated Horeseshoe Crab and Hela cancer cells were performed with COXRALM. Also during Phase II, the Imaging X-Ray Laser Microscope (IXRALM) was designed and constructed. This paper describes the development of each of the microscopes and their application for research.

  1. Handbook of X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Arnaud, Keith A. (Editor); Smith, Randall K.; Siemiginowska, Aneta

    2011-01-01

    X-ray astronomy was born in the aftermath of World War II as military rockets were repurposed to lift radiation detectors above the atmosphere for a few minutes at a time. These early flights detected and studied X-ray emission from the Solar corona. The first sources beyond the Solar System were detected during a rocket flight in 1962 by a team headed by Riccardo Giaccom at American Science and Engineering, a company founded by physicists from MIT. The rocket used Geiger counters with a system designed to reduce non-X-ray backgrounds and collimators limiting the region of sky seen by the counters. As the rocket spun, the field of view (FOV) happened to pass over what was later found to be the brightest non-Solar X-ray source; later designated See X-1. It also detected a uniform background glow which could not be resolved into individual sources. A follow-up campaign using X-ray detectors with better spatial resolution and optical telescopes identified See X-1 as an interacting binary with a compact (neutron star) primary. This success led to further suborbital rocket flights by a number of groups. More X-ray binaries were discovered, as well as X-ray emission from supernova remnants, the radio galaxies M87 and Cygnus-A, and the Coma cluster. Detectors were improved and Geiger counters were replaced by proportional counters, which provided information about energy spectra of the sources. A constant challenge was determining precise positions of sources as only collimators were available.

  2. Jet Charge Tagging at CDF using Run II Data

    NASA Astrophysics Data System (ADS)

    Paus, Christoph

    2004-05-01

    We present a study of the jet charge tagging in Run II CDF. The jet charge tagging method is applied to determine the b/barb-quark flavor of B hadrons at the time of production in a sample of b arrow ℓ ν X decays collected in 2002-2003.

  3. Synthesis and characterization of a series of transition metal complexes with a new symmetrical polyoxaaza macroacyclic Schiff base ligand: X-ray crystal structure of cobalt(II) and nickel(II) complexes and their antibacterial properties

    NASA Astrophysics Data System (ADS)

    Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Valencia, Laura

    2013-01-01

    A new symmetrical [N4O2] hexadentate Schiff base ligand, (E)-N-(pyridin-2-ylmethylene)-2-(3-(2-((E)-pyridin-2-lmethyleneamino)phenoxy)naphthalen-2-yloxy)benzenamine, abbreviated to L, and its complexes of Ni(II), Cu(II), Zn(II), Co(II), Cd(II) and Mn(II) have been synthesized in the presence of metal ions. The complexes were structurally characterized by elemental analyses, IR, UV-Vis, NMR and molar conductivity. The crystal structures of two complexes, [NiL(ONO2)2]·2H2O and [CoLCl2]CH3OH·0.5H2O, have been determined by a single crystal X-ray diffraction study. In these complexes, the ligand is coordinated in a neutral form via pyridine and azomethine nitrogen atoms. The metal ions complete their six coordination with two coordinated nitrate or chloride ions, forming a distorted octahedral geometry. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Enterococcus faecalis, Bacillus cereus and Staphylococcus epid and also against the three Gram-negative bacteria: Citrobacter freundii, Enterobacter aerogenes and Salmonella typhi. The activity data show that the complexes are more potent antibacterials than the parent Schiff base.

  4. X-ray Microscopy Beamlines at SSRF--Present Status and Future Plan

    SciTech Connect

    Xu, H.; Yu, X.; Tai, R.

    2011-09-09

    The Shanghai Synchrotron Radiation Facility (SSRF) is a 3.5-GeV third-generation light source. The facility has been open for user experiments since May, 2009. This high-brightness x-ray source is an ideal platform for x-ray microscopy. Presently, SSRF has three beamlines related to x-ray microscopy or imaging, namely the soft x-ray spectromicroscopy beamline (STXM), the hard x-ray microfocusing beamline, and the x-ray imaging beamline. The construction of SSRF phase-II beamlines will be carried out during 2011-2017. Seven additional beamlines for x-ray microscopy or imaging will be built.

  5. X-ray absorption spectroscopy of metalloproteins.

    PubMed

    Ward, Jesse; Ollmann, Emily; Maxey, Evan; Finney, Lydia A

    2014-01-01

    Metalloproteins are enormously important in biology. While a variety of techniques exist for studying metals in biology, X-ray absorption spectroscopy is particularly useful in that it can determine the local electronic and physical structure around the metal center, and is one of the few avenues for studying "spectroscopically silent" metal ions like Zn(II) and Cu(I) that have completely filled valence bands. While X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) are useful for studying metalloprotein structure, they suffer the limitation that the detected signal is an average of all the various metal centers in the sample, which limits its usefulness for studying metal centers in situ or in cell lysates. It would be desirable to be able to separate the various proteins in a mixture prior to performing X-ray absorption studies, so that the derived signal is from one species only. Here we describe a method for performing X-ray absorption spectroscopy on protein bands following electrophoretic separation and western blotting.

  6. Optics for coherent X-ray applications

    PubMed Central

    Yabashi, Makina; Tono, Kensuke; Mimura, Hidekazu; Matsuyama, Satoshi; Yamauchi, Kazuto; Tanaka, Takashi; Tanaka, Hitoshi; Tamasaku, Kenji; Ohashi, Haruhiko; Goto, Shunji; Ishikawa, Tetsuya

    2014-01-01

    Developments of X-ray optics for full utilization of diffraction-limited storage rings (DLSRs) are presented. The expected performance of DLSRs is introduced using the design parameters of SPring-8 II. To develop optical elements applicable to manipulation of coherent X-rays, advanced technologies on precise processing and metrology were invented. With propagation-based coherent X-rays at the 1 km beamline of SPring-8, a beryllium window fabricated with the physical-vapour-deposition method was found to have ideal speckle-free properties. The elastic emission machining method was utilized for developing reflective mirrors without distortion of the wavefronts. The method was further applied to production of diffraction-limited focusing mirrors generating the smallest spot size in the sub-10 nm regime. To enable production of ultra-intense nanobeams at DLSRs, a low-vibration cooling system for a high-heat-load monochromator and advanced diagnostic systems to characterize X-ray beam properties precisely were developed. Finally, new experimental schemes for combinative nano-analysis and spectroscopy realised with novel X-ray optics are discussed. PMID:25177986

  7. Hard X-Ray Emission of X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, P.

    1999-01-01

    The primary goal of this proposal was to perform an accurate measurement of the broadband x-ray spectrum of a neutron-star low-mass x-ray binary found in a hard x-ray state. This goal was accomplished using data obtained under another proposal, which has provided exciting new information on the hard x-ray emission of neutron-star low-mass x-ray binaries. In "BeppoSAX Observations of the Atoll X-Ray Binary 4U0614+091", we present our analysis of the spectrum of 4U0614+091 over the energy band from 0.3-150 keV. Our data confirm the presence of a hard x-ray tail that can be modeled as thermal Comptonization of low-energy photons on electrons having a very high temperature, greater than 220 keV, or as a non-thermal powerlaw. Such a very hard x-ray spectrum has not been previously seen from neutron-star low-mass x-ray binaries. We also detected a spectral feature that can be interpreted as reprocessing, via Compton reflection, of the direct emission by an optically-thick disk and found a correlation between the photon index of the power-law tail and the fraction of radiation reflected which is similar to the correlation found for black hole candidate x-ray binaries and Seyfert galaxies. A secondary goal was to measure the timing properties of the x-ray emission from neutronstar low-mass x-ray binaries in their low/hard states.

  8. Technologies for manufacturing of high angular resolution multilayer coated optics for the New Hard X-ray Mission: a status report II

    NASA Astrophysics Data System (ADS)

    Vernani, D.; Borghi, G.; Binda, R.; Citterio, O.; Grisoni, G.; Kools, J.; Marioni, F.; Orlandi, A.; Ritucci, A.; Sironi, G.; Valsecchi, G.; Basso, S.; Pareschi, G.; Spiga, D.; Tagliaferri, G.; Negri, B.

    2010-07-01

    Focusing mirrors manufactured via galvanic replication process from negative shape mandrels is the candidate solution for some of next future X-ray missions. Media Lario Technologies (MLT) is the industrial enabler developing, in collaboration with Brera Astronomical Observatory (INAF/OAB) and Italian Space Agency, the Optical Payload for the New Hard X-ray Mission (NHXM) Italian project. The current and ongoing development activities in Media Lario Technologies complement the electroforming technology with a suite of critical manufacturing and assembly of the Mirror Module Unit. In this paper, the progress on mandrels manufacturing, mirror shell replication, multilayer coating deposition and mirror module integration, leading to the manufacturing and testing of some astronomical Hard X-ray Engineering Models, is reported. Mandrel production is a key point in terms of performances and schedule; the results from mandrels fabricated using a proprietary multistep surface finishing process are reported. The progress in the replication of ultrathin Nickel and Nickel-Cobalt substrates gold coated mirror shells is reported together with the results of MLT Magnetron Sputtering multilayer coating technology for the hard x-ray waveband and its application to Pt/C.

  9. Polarized X-rays from accreting neutron stars

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Dipankar

    2016-07-01

    Accreting neutron stars span a wide range in X-ray luminosity and magnetic field strength. Accretion may be wind-fed or disk-fed, and the dominant X-ray flux may originate in the disk or a magnetically confined accretion column. In all such systems X-ray polarization may arise due to Compton or Magneto-Compton scattering, and on some occasions polarization of non-thermal emission from jet-like ejection may also be detectable. Spectral and temporal behaviour of the polarized X-rays would carry information regarding the radiation process, as well as of the matter dynamics - and can assist the detection of effects such as the Lense-Thirring precession. This talk will review our current knowledge of the expected X-ray polarization from accreting neutron stars and explore the prospects of detection with upcoming polarimetry missions.

  10. X-ray grating interferometry for 9.25 keV design energy at a liquid-metal-jet source

    NASA Astrophysics Data System (ADS)

    Balles, A.; Fella, Ch.; Dittmann, J.; Wiest, W.; Zabler, S.; Hanke, R.

    2016-01-01

    In this paper we present a grating interferometer setup with a liquid-metal-jet source and a high resolution detector. It will be shown that this source is suitable for interferometer setups as it delivers a sufficient spatial coherence that makes a source grating unnecessary. This is confirmed twice by the results of an interferometer setup and a single grating setup, respectively. Both show comparable information on the samples. Furthermore, it was possible to measure the Talbot effect due to the self-built high resolution detector with an effective pixel size of 0.67 µm and due to the coherence of the source, thanks to a small spot size of a few microns. The information on the absorption of a nylon fiber is observed to include inline phase contrast effects. The dark-field signal of a carbon fiber reinforced polymer (CFRP) is not quite well understood because of its inhomogeneity.

  11. XID II: STATISTICAL CROSS-ASSOCIATION OF ROSAT BRIGHT SOURCE CATALOG X-RAY SOURCES WITH 2MASS POINT SOURCE CATALOG NEAR-INFRARED SOURCES

    SciTech Connect

    Haakonsen, Christian Bernt; Rutledge, Robert E. E-mail: rutledge@physics.mcgill.ca

    2009-09-01

    The 18,806 ROSAT All Sky Survey Bright Source Catalog (RASS/BSC) X-ray sources are quantitatively cross-associated with near-infrared (NIR) sources from the Two Micron All Sky Survey Point Source Catalog (2MASS/PSC). An association catalog is presented, listing the most likely counterpart for each RASS/BSC source, the probability P {sub id} that the NIR source and X-ray source are uniquely associated, and the probability P {sub no-id} that none of the 2MASS/PSC sources are associated with the X-ray source. The catalog includes 3853 high quality (P {sub id}>0.98) X-ray-NIR matches, 2280 medium quality (0.98 {>=} P {sub id}>0.9) matches, and 4153 low quality (0.9 {>=} P {sub id}>0.5) matches. Of the high quality matches, 1418 are associations that are not listed in the SIMBAD database, and for which no high quality match with a USNO-A2 optical source was presented for the RASS/BSC source in previous work. The present work offers a significant number of new associations with RASS/BSC objects that will require optical/NIR spectroscopy for classification. For example, of the 6133 P {sub id}>0.9 2MASS/PSC counterparts presented in the association catalog, 2411 have no classification listed in the SIMBAD database. These 2MASS/PSC sources will likely include scientifically useful examples of known source classes of X-ray emitters (white dwarfs, coronally active stars, active galactic nuclei), but may also contain previously unknown source classes. It is determined that all coronally active stars in the RASS/BSC should have a counterpart in the 2MASS/PSC, and that the unique association of these RASS/BSC sources with their NIR counterparts thus is confusion limited.

  12. The extended ROSAT-ESO Flux-Limited X-ray Galaxy Cluster Survey (REFLEX II). V. Exploring a local underdensity in the southern sky

    NASA Astrophysics Data System (ADS)

    Böhringer, Hans; Chon, Gayoung; Bristow, Martyn; Collins, Chris A.

    2015-02-01

    Several claims have been made that we are located in a locally underdense region of the Universe based on observations of supernovae and galaxy density distributions. Two recent studies of K-band galaxy surveys have, in particular, provided new support for a local underdensity in the galaxy distribution out to distances of 200-300 Mpc. If confirmed, such local underdensities would have important implications interpreting local measurements of cosmological parameters. Galaxy clusters have been shown to be ideal probes for tracing the large-scale structure of the Universe. In this paper we study the local density distribution in the southern sky with the X-ray detected galaxy clusters from the REFLEX II cluster survey. From the normalised comoving number density of clusters, we find an average underdensity of ~30-40% in the redshift range out to z ~ 0.04 (~170 Mpc) in the southern extragalactic sky with a significance greater than 3.4σ. On larger scales from 300 Mpc to over 1 Gpc, the density distribution appears remarkably homogeneous. The local underdensity seems to be dominated by the south Galactic cap region. A comparison of the cluster distribution with that of galaxies in the K-band from a recent study shows that galaxies and clusters trace each other very closely in density. In the south Galactic cap region both surveys find a local underdensity in the redshift range z = 0 to 0.05 and no significant underdensity in the north Galactic cap at southern latitudes. Cosmological models that attempt to interpret the cosmic acceleration, deduced from observations of type Ia supernovae, by a large local void without the need for reacceleration, require that we are located close to the centre of a roughly spherical void with a minimum size of ~300 Mpc. In contrast our results show that the local underdensity is not isotropic and limited to a size significantly smaller than 300 Mpc radius. Based on observations at the European Southern Observatory La Silla, Chile.

  13. Solar X-ray physics

    SciTech Connect

    Bornmann, P.L. )

    1991-01-01

    Research on solar X-ray phenomena performed by American scientists during 1987-1990 is reviewed. Major topics discussed include solar images observed during quiescent times, the processes observed during solar flares, and the coronal, interplanetary, and terrestrial phenomena associated with solar X-ray flares. Particular attention is given to the hard X-ray emission observed at the start of the flare, the energy transfer to the soft X-ray emitting plasma, the late resolution of the flare as observed in soft X-ray, and the rate of occurrence of solar flares as a function of time and latitude. Pertinent aspects of nonflaring, coronal X-ray emission and stellar flares are also discussed. 175 refs.

  14. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Stone, Gary F.; Bell, Perry M.; Robinson, Ronald B.; Chornenky, Victor I.

    2002-01-01

    A miniature x-ray source capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature x-ray source comprises a compact vacuum tube assembly containing a cathode, an anode, a high voltage feedthru for delivering high voltage to the anode, a getter for maintaining high vacuum, a connection for an initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is highly x-ray transparent and made, for example, from boron nitride. The compact size and potential for remote operation allows the x-ray source, for example, to be placed adjacent to a material sample undergoing analysis or in proximity to the region to be treated for medical applications.

  15. Topological X-Rays Revisited

    ERIC Educational Resources Information Center

    Lynch, Mark

    2012-01-01

    We continue our study of topological X-rays begun in Lynch ["Topological X-rays and MRI's," iJMEST 33(3) (2002), pp. 389-392]. We modify our definition of a topological magnetic resonance imaging and give an affirmative answer to the question posed there: Can we identify a closed set in a box by defining X-rays to probe the interior and without…

  16. The origin of the hard X-ray tail in neutron-star X-ray binaries

    NASA Astrophysics Data System (ADS)

    Reig, P.; Kylafis, N.

    2016-06-01

    Context. Neutron star X-ray binaries emit a compact, optically thick, relativistic radio jet during low-luminosity, usually hard states, as Galactic black-hole X-ray binaries do. When radio emission is bright, a hard power-law tail without evidence for an exponential cutoff is observed in most systems. Aims: We have developed a jet model that explains many spectral and timing properties of black-hole binaries in the states where a jet is present. Our goal is to investigate whether our jet model can reproduce the hard tail, with the correct range of photon index and the absence of a high-energy cutoff, in neutron-star X-ray binaries. Methods: We performed Monte Carlo simulations of the Compton upscattering of soft, accretion-disk or boundary layer photons in the jet and computed the emergent energy spectra, as well as the time lag of hard photons with respect to softer ones as a function of Fourier frequency. We fit the energy spectra with a power law modified by an exponential cutoff at high energy. Results: We demonstrate that our jet model naturally explains the observed power-law distribution with photon index in the range 1.8-3. With an appropriate choice of the parameters, the cutoff expected from Comptonization is shifted to energies above ~300 keV, producing a pure power law without any evidence for a rollover, in agreement with the observations. Conclusions: Our results reinforce the idea that the link between the outflow (jet) and inflow (disk) in X-ray binaries does not depend on the nature of the compact object, but on the process of accretion. Furthermore, we address the differences between jets in black-hole and neutron-star X-ray binaries and predict that the break frequency in the spectral energy distribution of neutron-star X-ray binaries, as a class, will be lower than that of black-hole binaries.

  17. X-ray spectroscopy of manganese clusters

    SciTech Connect

    Grush, M.M. |

    1996-06-01

    Much of this thesis represents the groundwork necessary in order to probe Mn clusters more productively than with conventional Mn K-edge XAS and is presented in Part 1. Part 2 contains the application of x-ray techniques to Mn metalloproteins and includes a prognosis at the end of each chapter. Individual Mn oxidation states are more readily distinguishable in Mn L-edge spectra. An empirical mixed valence simulation routine for determining the average Mn oxidation state has been developed. The first Mn L-edge spectra of a metalloprotein were measured and interpreted. The energy of Mn K{beta} emission is strongly correlated with average Mn oxidation state. K{beta} results support oxidation states of Mn(III){sub 2}(IV){sub 2} for the S{sub 1} state of Photosystem II chemical chemically reduced preparations contain predominantly Mn(II). A strength and limitation of XAS is that it probes all of the species of a particular element in a sample. It would often be advantageous to selectively probe different forms of the same element. The first demonstration that chemical shifts in x-ray fluorescence energies can be used to obtain oxidation state-selective x-ray absorption spectra is presented. Spin-dependent spectra can also be used to obtain a more simplified picture of local structure. The first spin-polarized extended x-ray absorption fine structure using Mn K{beta} fluorescence detection is shown.

  18. Beyond hard x-ray photoelectron spectroscopy: Simultaneous combination with x-ray diffraction

    SciTech Connect

    Rubio-Zuazo, Juan; Castro, German R.

    2013-05-15

    Hard x-ray photoelectron spectroscopy (HAXPES) is a powerful and novel emerging technique for the nondestructive determination of electronic properties and chemical composition of bulk, buried interfaces and surfaces. It benefits from the exceptionally large escape depth of high kinetic energy photoelectrons, increasing the information depth up to several tens of nanometers. Complementing HAXPES with an atomic structure sensitive technique (such as x-ray diffraction) opens a new research field with major applications for materials science. At SpLine, the Spanish CRG beamline at the European Synchrotron Radiation Facility, we have developed a novel experimental set-up that combines HAXPES and x-ray diffraction (x-ray reflectivity, surface x-ray diffraction, grazing incidence x-ray diffraction, and reciprocal space maps). Both techniques can be operated simultaneously on the same sample and using the same excitation source. The set-up includes a robust 2S + 3D diffractometer hosting a ultrahigh vacuum chamber equipped with a unique photoelectron spectrometer (few eV < electron kinetic energy < 15 keV), x-ray tube (Mg/Ti), 15 keV electron gun, and auxiliary standard surface facilities (molecular beam epitaxy evaporator, ion gun, low energy electron diffraction, sample heating/cooling system, leak valves, load-lock sample transfer, etc.). This end-station offers the unique possibility of performing simultaneous HAXPES + x-ray diffraction studies. In the present work, we describe the experimental set-up together with two experimental examples that emphasize its outstanding capabilities: (i) nondestructive characterization of the Si/Ge and HfO{sub 2}/SiO{sub 2} interfaces on Ge-based CMOS devices, and (ii) strain study on La{sub 0.7}Ca{sub 0.3}MnO{sub 3} ultrathin films grown on SrTiO{sub 3}(001) substrate.

  19. X-ray irradiated model stellar atmospheres

    NASA Astrophysics Data System (ADS)

    Madej, J.; Różańska, A.

    2000-04-01

    We present equations and details of the computer code for precise calculation of LTE model atmospheres which are illuminated by an external radiation field. Both radiative and hydrostatic equilibrium, and coherent Thomson electron scattering have been assumed. Radiation field at each frequency and depth level is computed with the method of variable Eddington factors. The code is fully suitable for the study of mutual illumination effects in close binaries. We have subsequently computed few sets of model stellar atmospheres of Teff = 1.8x 104 K, and log g = 4.0 (B3 V type star), consisting of hydrogen and helium in solar proportion, and iron of number abundance NFe / N_H = 3.7 x 10-5. We assume, that the atmosphere is illuminated by isotropic X-rays of diluted thermal spectral distribution with temperature Trad =108 K. In case of iron-rich models external X-rays cause heating of the uppermost layers up to 4 x 106 K. Such a choice of Teff and Trad differing by 4 orders of magnitude is relevant to the supposed conditions on some rings of the accretion disk in active galactic nuclei (AGN), illuminated by an X-ray source. Our code qualitatively reproduces the structure of an atmosphere and its spectrum for wavelengths ranging from infrared to X-rays. Outgoing spectra clearly exhibit all three components: spectrum of B star, external X-ray blackbody spectrum partly backscattered by the model atmosphere, and radiation from the uppermost layers, heated to very high temperatures. The latter shows He I and He II Lyman opacity jumps, and numerous b-f jumps of highly ionized iron, all of them in emission. We demonstrate that in all atmospheres of our paper the external illumination by X-rays reduces the H I Lyman jump. This is in agreement with observations of AGNs spectra.

  20. Identification campaign of supernova remnant candidates in the Milky Way. II. X-ray studies of G38.7-1.4

    SciTech Connect

    Huang, R. H. H.; Wu, J. H. K.; Kong, A. K. H.; Hui, C. Y.; Seo, K. A.; Trepl, L.

    2014-04-20

    We report on XMM-Newton and Chandra observations of the Galactic supernova remnant candidate G38.7-1.4, together with complementary radio, infrared, and γ-ray data. An approximately elliptical X-ray structure is found to be well correlated with a radio shell as seen by the Very Large Array. The X-ray spectrum of G38.7-1.4 can be well described by an absorbed collisional ionization equilibrium plasma model, which suggests the plasma is shock heated. Based on the morphology and the spectral behavior, we suggest that G38.7-1.4 is indeed a supernova remnant belonging to a mix-morphology category.

  1. Refinement of the Compton-Rayleigh scatter ratio method for use on the Mars Science Laboratory alpha particle X-ray spectrometer: II - Extraction of invisible element content

    NASA Astrophysics Data System (ADS)

    Perrett, Glynis M.; Campbell, John L.; Gellert, Ralf; King, Penelope L.; Nield, Emily; O'Meara, Joanne M.; Pradler, Irina

    2016-02-01

    The intensity ratio C/R between Compton and Rayleigh scatter peaks of the exciting Pu L X-rays in the alpha particle X-ray spectrometer (APXS) is strongly affected by the presence of very light elements such as oxygen which cannot be detected directly by the APXS. C/R values are determined along with element concentrations by fitting APXS spectra of geochemical reference materials (GRMs) with the GUAPX code. A quantity K is defined as the ratio between the C/R value determined by Monte Carlo simulation based on the measured element concentrations and the fitted C/R value from the spectrum. To ensure optimally accurate K values, the choice of appropriate GRMs is explored in detail, with attention paid to Rb and Sr, whose characteristic Kα X-ray peaks overlap the Pu Lα scatter peaks. The resulting relationship between the ratio K and the overall oxygen fraction is linear. This provides a calibration from which the concentration of additional light invisible constituents (ALICs) such as water may be estimated in unknown rock and conglomerate samples. Several GRMs are used as 'unknowns' in order to evaluate the accuracy of ALIC concentrations derived in this manner.

  2. X-ray beam pointer

    NASA Technical Reports Server (NTRS)

    Nelson, C. W.

    1980-01-01

    Inexpensive, readily assembled pointer aims X-ray machine for welded assembly radiographs. Plumb bob used for vertical alinement and yardstick used to visualize X-ray paths were inconvenient and inaccurate. Pointer cuts alinement time by one-half and eliminates necessity of retakes. For 3,000 weld radiographs, pointer will save 300 worker-hours and significant materials costs.

  3. X-ray based extensometry

    NASA Technical Reports Server (NTRS)

    Jordan, E. H.; Pease, D. M.

    1988-01-01

    A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology.

  4. X-Ray Tomographic Reconstruction

    SciTech Connect

    Bonnie Schmittberger

    2010-08-25

    Tomographic scans have revolutionized imaging techniques used in medical and biological research by resolving individual sample slices instead of several superimposed images that are obtained from regular x-ray scans. X-Ray fluorescence computed tomography, a more specific tomography technique, bombards the sample with synchrotron x-rays and detects the fluorescent photons emitted from the sample. However, since x-rays are attenuated as they pass through the sample, tomographic scans often produce images with erroneous low densities in areas where the x-rays have already passed through most of the sample. To correct for this and correctly reconstruct the data in order to obtain the most accurate images, a program employing iterative methods based on the inverse Radon transform was written. Applying this reconstruction method to a tomographic image recovered some of the lost densities, providing a more accurate image from which element concentrations and internal structure can be determined.

  5. Focusing X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen; Brissenden, Roger; Davis, William; Elsner, Ronald; Elvis, Martin; Freeman, Mark; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhall; Jerlus, Diab; Juda, Michael; Kolodziejczak, Jeffrey; Murray, Stephen; Petre, Robert; Podgorski, William; Ramsey, Brian; Reid, Paul; Saha, Timo; Wolk, Scott; Troller-McKinstry, Susan; Weisskopf, Martin; Wilke, Rudeger; Zhang, William

    2010-01-01

    During the half-century history of x-ray astronomy, focusing x-ray telescopes, through increased effective area and finer angular resolution, have improved sensitivity by 8 orders of magnitude. Here, we review previous and current x-ray-telescope missions. Next, we describe the planned next-generation x-ray-astronomy facility, the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility, Generation X. Its scientific objectives will require very large areas (about 10,000 sq m) of highly-nested, lightweight grazing-incidence mirrors, with exceptional (about 0.1-arcsec) resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.

  6. X-ray shearing interferometer

    DOEpatents

    Koch, Jeffrey A.

    2003-07-08

    An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

  7. Swift Observations of the X-Ray-Bright GRB 050315

    NASA Astrophysics Data System (ADS)

    Vaughan, S.; Goad, M. R.; Beardmore, A. P.; O'Brien, P. T.; Osborne, J. P.; Page, K. L.; Barthelmy, S. D.; Burrows, D. N.; Campana, S.; Cannizzo, J. K.; Capalbi, M.; Chincarini, G.; Cummings, J. R.; Cusumano, G.; Giommi, P.; Godet, O.; Hill, J. E.; Kobayashi, S.; Kumar, P.; La Parola, V.; Levan, A.; Mangano, V.; Mészáros, P.; Moretti, A.; Morris, D. C.; Nousek, J. A.; Pagani, C.; Palmer, D. M.; Racusin, J. L.; Romano, P.; Tagliaferri, G.; Zhang, B.; Gehrels, N.

    2006-02-01

    This paper discusses Swift observations of the γ-ray burst GRB 050315 (z=1.949) from 80 s to 10 days after the onset of the burst. The X-ray light curve displayed a steep early decay (t-5) for ~200 s and several breaks. However, both the prompt hard X-ray/γ-ray emission (observed by the BAT) and the first ~300 s of X-ray emission (observed by the XRT) can be explained by exponential decays, with similar decay constants. Extrapolating the BAT light curve into the XRT band suggests that the rapidly decaying, early X-ray emission was simply a continuation of the fading prompt emission; this strong similarity between the prompt γ-ray and early X-ray emission may be related to the simple temporal and spectral character of this X-ray-rich GRB. The prompt (BAT) spectrum was steep down to ~15 keV and appeared to continue through the XRT bandpass, implying a low peak energy, inconsistent with the Amati relation. Following the initial steep decline, the X-ray afterglow did not fade for ~1.2×104 s, after which time it decayed with a temporal index of α~0.7, followed by a second break at ~2.5×105 s to a slope of α~2. The apparent ``plateau'' in the X-ray light curve, after the early rapid decay, makes this one of the most extreme examples of the steep-flat-steep X-ray light curves revealed by Swift. If the second afterglow break is identified with a jet break, then the jet opening angle was θ0~5deg, implying Eγ>~1050 ergs.

  8. Accretion and Outflows in X-ray Binaries: What's Really Going on During X-ray Quiescence

    NASA Astrophysics Data System (ADS)

    MacDonald, Rachel K. D.; Bailyn, Charles D.; Buxton, Michelle

    2015-01-01

    X-ray binaries, consisting of a star and a stellar-mass black hole, are wonderful laboratories for studying accretion and outflows. They evolve on timescales quite accessible to us, unlike their supermassive cousins, and allow the possibility of gaining a deeper understanding of these two common astrophysical processes. Different wavelength regimes reveal different aspects of the systems: radio emission is largely generated by outflows and jets, X-ray emission by inner accretion flows, and optical/infrared (OIR) emission by the outer disk and companion star. The search for relationships between these different wavelengths is thus an area of active research, aiming to reveal deeper connections between accretion and outflows.Initial evidence for a strong, tight correlation between radio and X-ray emission has weakened as further observations and newly-discovered sources have been obtained. This has led to discussions of multiple tracks or clusters, or the possibility that no overall relation exists for the currently-known population of X-ray binaries. Our ability to distinguish among these options is hampered by a relative lack of observations at lower luminosities, and especially of truly X-ray quiescent (non-outbursting) systems. Although X-ray binaries spend the bulk of their existence in quiescence, few quiescent sources have been observed and multiple observations of individual sources are largely nonexistent. Here we discuss new observations of the lowest-luminosity quiescent X-ray binary, A0620-00, and the place this object occupies in investigations of the radio/X-ray plane. For the first time, we also incorporate simultaneous OIR data with the radio and X-ray data.In December 2013 we took simultaneous observations of A0620-00 in the X-ray (Chandra), the radio (EVLA), and the OIR (SMARTS 1.3m). These X-ray and radio data allowed us to investigate similarities among quiescent X-ray binaries, and changes over time for this individual object, in the radio/X-ray

  9. Hard X-Ray Emission of X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, Phillip

    1997-01-01

    The main results from this investigation were serendipitous. The long observation approved for the study of the hard X-ray emission of X-ray bursters lead, instead, to one of the largest early samples of the behavior of fast quasi-periodic oscillations (QPOS) in an atoll sources. Our analysis of this data set lead to the several important discoveries including the existence of a robust correlation between QPO frequency and the flux of a soft blackbody component of the X-ray spectrum in the atoll source 4U 0614+091.

  10. X-ray imaging physics for nuclear medicine technologists. Part 1: Basic principles of x-ray production.

    PubMed

    Seibert, J Anthony

    2004-09-01

    The purpose is to review in a 4-part series: (i) the basic principles of x-ray production, (ii) x-ray interactions and data capture/conversion, (iii) acquisition/creation of the CT image, and (iv) operational details of a modern multislice CT scanner integrated with a PET scanner. Advances in PET technology have lead to widespread applications in diagnostic imaging and oncologic staging of disease. Combined PET/CT scanners provide the high-resolution anatomic imaging capability of CT with the metabolic and physiologic information by PET, to offer a significant increase in information content useful for the diagnostician and radiation oncologist, neurosurgeon, or other physician needing both anatomic detail and knowledge of disease extent. Nuclear medicine technologists at the forefront of PET should therefore have a good understanding of x-ray imaging physics and basic CT scanner operation, as covered by this 4-part series. After reading the first article on x-ray production, the nuclear medicine technologist will be familiar with (a) the physical characteristics of x-rays relative to other electromagnetic radiations, including gamma-rays in terms of energy, wavelength, and frequency; (b) methods of x-ray production and the characteristics of the output x-ray spectrum; (c) components necessary to produce x-rays, including the x-ray tube/x-ray generator and the parameters that control x-ray quality (energy) and quantity; (d) x-ray production limitations caused by heating and the impact on image acquisition and clinical throughput; and (e) a glossary of terms to assist in the understanding of this information.

  11. An Extensive Census of Hubble Space Telescope Counterparts to Chandra X-Ray Sources in the Globular Cluster 47 Tucanae. II. Time Series and Analysis

    NASA Astrophysics Data System (ADS)

    Edmonds, Peter D.; Gilliland, Ronald L.; Heinke, Craig O.; Grindlay, Jonathan E.

    2003-10-01

    We report time series and variability information for the optical identifications of X-ray sources in 47 Tucanae reported in Paper I (at least 22 cataclysmic variables [CVs] and 29 active binaries). The radial distribution of the CVs is indistinguishable from that of the millisecond pulsars (MSPs) detected by Freire et al. A study of the eight CVs with secure orbital periods (two obtained from the Chandra study of Grindlay et al.) shows that the 47 Tuc CVs have fainter accretion disks, in the V band, than field CVs with similar periods. These faint disks and the faint absolute magnitudes (MV) of the 47 Tuc CVs suggests they have low accretion rates. One possible explanation is that the 47 Tuc objects may be a more representative sample of CVs, down to our detection threshold, than the CVs found in the field (where many low accretion rate systems are believed to be undiscovered), showing the advantages of deep globular cluster observations. The median FX/Fopt value for the 47 Tuc CVs is higher than that of all known classes of field CV, partly because of the faint MV values and partly because of the relatively high X-ray luminosities (LX). The latter are only seen in DQ Her systems in the field, but the 47 Tuc CVs are much fainter optically than most field DQ Her's. Previous work by Edmonds et al. has shown that the four brightest CVs in NGC 6397 have optical spectra and broadband colors that are consistent with DQ Her's having lower than average accretion rates. Some combination of magnetic behavior and low accretion rates may be able to explain our observations, but the results at present are ambiguous, since no class of field CV has distributions of both LX and MV that are consistent with those of the 47 Tuc CVs. The radial distribution of the X-ray detected active binaries is indistinguishable from that of the much larger sample of optical variables (eclipsing and contact binaries and BY Dra variables) detected in previous Wide Field Planetary Camera 2 (WFPC2

  12. Variability and the X-ray/UV ratio of active galactic nuclei. II. Analysis of a low-redshift Swift sample

    NASA Astrophysics Data System (ADS)

    Vagnetti, F.; Antonucci, M.; Trevese, D.

    2013-02-01

    Context. Variability, both in X-ray and optical/UV, affects the well-known anti-correlation between the αox spectral index and the UV luminosity of active galactic nuclei, contributing part of the dispersion around the average correlation (intra-source dispersion) in addition to the differences among the time-average αox values from source to source (inter-source dispersion). Aims: We aim to evaluate the intrinsic αox variations in individual objects and their effect on the dispersion of the αox - LUV anti-correlation. Methods: We used simultaneous UV/X-ray data from Swift observations of a low-redshift sample to derive the epoch-dependent αox(t) indices. We corrected for the host galaxy contribution by a spectral fit of the optical/UV data. We computed ensemble structure functions to analyse the variability of multi-epoch data. Results: We find a strong intrinsic αox variability, which significantly contributes (~40% of the total variance) to the dispersion of the αox - LUV anti-correlation (intra-source dispersion). The strong X-ray variability and weaker UV variability of this sample are comparable to other samples of low-z active galactic nuclei, and are neither caused by the high fraction of strongly variable narrow line Seyfert 1 galaxies, nor by dilution of the optical variability by the host galaxies. Dilution instead affects the slope of the anti-correlation, which steepens, once corrected, and becomes similar to higher luminosity sources. The structure function of αox increases with the time lag up to about one month. This indicates the important contribution of the intermediate-to-long timescale variations, which are possibly generated in the outer parts of the accretion disk. Table 1 is available in electronic form at http://www.aanda.org

  13. HOT ELECTROMAGNETIC OUTFLOWS. II. JET BREAKOUT

    SciTech Connect

    Russo, Matthew; Thompson, Christopher

    2013-08-20

    We consider the interaction between radiation, matter, and a magnetic field in a compact, relativistic jet. The entrained matter accelerates outward as the jet breaks out of a star or other confining medium. In some circumstances, such as gamma-ray bursts (GRBs), the magnetization of the jet is greatly reduced by an advected radiation field while the jet is optically thick to scattering. Where magnetic flux surfaces diverge rapidly, a strong outward Lorentz force develops and radiation and matter begin to decouple. The increase in magnetization is coupled to a rapid growth in Lorentz factor. We take two approaches to this problem. The first examines the flow outside the fast magnetosonic critical surface, and calculates the flow speed and the angular distribution of the radiation field over a range of scattering depths. The second considers the flow structure on both sides of the critical surface in the optically thin regime, using a relaxation method. In both approaches, we find how the terminal Lorentz factor and radial profile of the outflow depend on the radiation intensity and optical depth at breakout. The effect of bulk Compton scattering on the radiation spectrum is calculated by a Monte Carlo method, while neglecting the effects of internal dissipation. The peak of the scattered spectrum sits near the seed peak if radiation pressure dominates the acceleration, but is pushed to a higher frequency if the Lorentz force dominates. The unscattered seed radiation can form a distinct, low-frequency component of the spectrum, especially if the magnetic Poynting flux dominates.

  14. A study of the x ray environment of radio galaxies

    NASA Technical Reports Server (NTRS)

    Rhee, George F.; Burns, Jack O.; Owen, Frazer

    1993-01-01

    We are currently working on a program to use extensive x-ray and radio databases to investigate the relationship between extended radio emission and environment in clusters of galaxies. The radio galaxy morphology is determined using VLA imaging and the x-ray properties are determined from Einstein IPC images. This study is motivated by the hypothesis that the key to understanding radio galaxies lies in the local environment. To test this hypothesis we have studied the detailed relationship between galaxy radio emission and the x-ray morphology of their parent clusters. In this pilot study we have used 35 radio sources found in 27 clusters. We have determined the position angle of the x-ray and radio emission, and x-ray and radio luminosities. The x-ray position was taken to be the position of peak flux of the subclump containing the radio galaxy. The radio position was taken to be the position of the galaxy. We do not find a correlation between the x-ray and radio source position angle. This remains true when the sample is divided into subsamples according to radio morphology (wide angle tail, twin jet, narrow angle tail galaxies). We find a weak correlation between the radio source luminosity and the x-ray luminosity. We have computed the distance from the radio galaxy position to the center of the x-ray clump. We find a mean distance from the x-ray clump center of 0.16 Mpc for the radio galaxies in this sample. The mean distance to the nearest clump of x-ray emission is typically half the distance to the optical cluster center. We thus find strong evidence that radio galaxies are located very close to clumps of x-ray emission. These subclumps are not always affiliated with the central cluster x-ray emission. This supports our hypothesis that x-ray emission may provide a key to understanding radio galaxy morphology. We find evidence that radio galaxies occur in clusters that contain prominent substructures. Radio galaxies may thus provide an added diagnostic of

  15. X-Ray photonics: X-rays inspire electron movies

    NASA Astrophysics Data System (ADS)

    Vrakking, Marc J. J.; Elsaesser, Thomas

    2012-10-01

    The advent of high-energy, short-pulse X-ray sources based on free-electron lasers, laser plasmas and high-harmonic generation is now making it possible to probe the dynamics of electrons within molecules.

  16. Properties of impurity-bearing ferrihydrite II: Insights into the surface structure and composition of pure, Al- and Si-bearing ferrihydrite from Zn(II) sorption experiments and Zn K-edge X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Cismasu, A. Cristina; Levard, Clément; Michel, F. Marc; Brown, Gordon E.

    2013-10-01

    Naturally occurring ferrihydrite often contains impurities such as Al and Si, which can impact its chemical reactivity with respect to metal(loid) adsorption and (in)organic or microbially induced reductive dissolution. However, the surface composition of impure ferrihydrites is not well constrained, and this hinders our understanding of the factors controlling the surface reactivity of these nanophases. In this study, we conducted Zn(II) adsorption experiments combined with Zn K-edge X-ray absorption spectroscopy measurements on pure ferrihydrite (Fh) and Al- or Si-bearing ferrihydrites containing 10 and 20 mol% Al or Si (referred to as 10AlFh, 20AlFh and 10SiFh, 20SiFh) to evaluate Zn(II) uptake in relation to Zn(II) speciation at their surfaces. Overall, Zn(II) uptake at the surface of AlFh is similar to that of pure Fh, and based on Zn K-edge EXAFS data, Zn(II) speciation at the surface of Fh and AlFh also appears similar. Binuclear bidentate IVZn-VIFe complexes (at ∼3.46 Å (2C[1]) and ∼3.25 Å (2C[2])) were identified at low Zn(II) surface coverages from Zn K-edge EXAFS fits. With increasing Zn(II) surface coverage, the number of second-neighbor Fe ions decreased, which was interpreted as indicating the formation of IVZn polymers at the ferrihydrite surface, and a deviation from Langmuir uptake behavior. Zn(II) uptake at the surface of SiFh samples was more significant than at Fh and AlFh surfaces, and was attributed to the formation of outer-sphere complexes (on average 24% of sorbed Zn). Although similar Zn-Fe/Zn distances were obtained for the Zn-sorbed SiFh samples, the number of Fe second neighbors was lower in comparison with Fh. The decrease in second-neighbor Fe is most pronounced for sample 20SiFh, suggesting that the amount of reactive surface Fe sites diminishes with increasing Si content. Although our EXAFS results shown here do not provide evidence for the existence of Zn-Al or Zn-Si complexes, their presence is not excluded for Zn-sorbed Al

  17. Be/X-ray binaries

    NASA Astrophysics Data System (ADS)

    Reig, Pablo

    2011-03-01

    The interest in X/ γ-ray Astronomy has grown enormously in the last decades thanks to the ability to send X-ray space missions above the Earth’s atmosphere. There are more than half a million X-ray sources detected and over a hundred missions (past and currently operational) devoted to the study of cosmic X/ γ rays. With the improved sensibilities of the currently active missions new detections occur almost on a daily basis. Among these, neutron-star X-ray binaries form an important group because they are among the brightest extra-solar objects in the sky and are characterized by dramatic variability in brightness on timescales ranging from milliseconds to months and years. Their main source of power is the gravitational energy released by matter accreted from a companion star and falling onto the neutron star in a relatively close binary system. Neutron-star X-ray binaries divide into high-mass and low-mass systems according to whether the mass of the donor star is above ˜8 or below ˜2 M⊙, respectively. Massive X-ray binaries divide further into supergiant X-ray binaries and Be/X-ray binaries depending on the evolutionary status of the optical companion. Virtually all Be/X-ray binaries show X-ray pulsations. Therefore, these systems can be used as unique natural laboratories to investigate the properties of matter under extreme conditions of gravity and magnetic field. The purpose of this work is to review the observational properties of Be/X-ray binaries. The open questions in Be/X-ray binaries include those related to the Be star companion, that is, the so-called “Be phenomenon”, such as, timescales associated to the formation and dissipation of the equatorial disc, mass-ejection mechanisms, V/ R variability, and rotation rates; those related to the neutron star, such as, mass determination, accretion physics, and spin period evolution; but also, those that result from the interaction of the two constituents, such as, disc truncation and mass

  18. X-ray burst sources

    NASA Technical Reports Server (NTRS)

    Lewin, W. H. G.

    1986-01-01

    There are about 100 bright X-ray sources in the Galaxy that are accretion-driven systems composed of a neutron star and a low mass companion that fills its critical Roche lobe. Many of these systems generate recurring X-ray bursts that are the result of thermonuclear flashes in the neutron star's surface layers, and are accompanied by a somewhat delayed optical burst due to X-ray heating of accretion disk. The Rapid Burster discovered in 1976 exhibits an interval between bursts that is strongly correlated with the energy in the preceding burst. There is no optical identification for this object.

  19. X-Ray Imaging System

    NASA Astrophysics Data System (ADS)

    1986-01-01

    The FluoroScan Imaging System is a high resolution, low radiation device for viewing stationary or moving objects. It resulted from NASA technology developed for x-ray astronomy and Goddard application to a low intensity x-ray imaging scope. FlouroScan Imaging Systems, Inc, (formerly HealthMate, Inc.), a NASA licensee, further refined the FluoroScan System. It is used for examining fractures, placement of catheters, and in veterinary medicine. Its major components include an x-ray generator, scintillator, visible light image intensifier and video display. It is small, light and maneuverable.

  20. Synthesis, characterization and spectroscopy studying of some metal complexes of a new Schiff base ligand; X-ray crystal structure, NMR and IR investigation of a new dodecahedron Cd(II) complex

    NASA Astrophysics Data System (ADS)

    Golbedaghi, Reza; Rezaeivala, Majid; Khalili, Maryam; Notash, Behrouz; Karimi, Javad

    2016-12-01

    Some new [Cd(H2L1)(NO3)]ClO4 (1), [Mn(H2L1)](ClO4)2 (2), [Ni(H2L1)](ClO4)2 (3) and [Cu(H2L1)](ClO4)2 (4) complexes were prepared by the reaction of a Schiff base ligand and M (II) metal ions in equimolar ratios (M = Cd, Mn, Ni and Cu). The ligand H2L1 was synthesized by reaction of 2-[2-(3-formyl phenoxy)propoxy]benzaldehyde and ethanol amine and characterized by IR, 1H,13C NMR spectroscopy and elemental analysis. The synthesized complexes were characterized with IR and elemental analysis in all cases and 1H, 13C NMR, and X-ray in the case of Cd(II) complex. The X-ray crystal structure of compound 1 showed that all nitrogen and oxygen atoms of Schiff base ligand (N2O4) and a molecule of nitrate with two donor oxygen atom have been coordinated to the metal ion and the Cd(II) ion is in an eight-coordinate environment that is best described as a distorted dodecahedron geometry.

  1. Comparing neutron and X-ray images from NIF implosions

    NASA Astrophysics Data System (ADS)

    Wilson, D. C.; Aragonez, R. J.; Archuleta, T. N.; Atkinson, D. P.; Barrios, M. A.; Batha, S. H.; Bower, D. E.; Bradley, D. K.; Buckles, R. A.; Clark, D. D.; Clark, D. S.; Clark, D. J.; Cradick, J. R.; Danly, C. R.; Day, R. D.; Dzenitis, J. M.; Drury, O. B.; Fatherley, V. E.; Felker, B.; Finch, J. P.; Fittinghoff, D. N.; Frank, M.; Gallegos, R. A.; Garcia, F. P.; Glenn, S. M.; Grim, G. P.; Guler, N.; Hsu, A. H.; Izumi, N.; Jaramillo, S. A.; Jones, O. S.; Kaufman, M. I.; Kilkenny, J. D.; Kyrala, G. A.; Le Pape, S.; Liddick, S. N.; Loomis, E. N.; Lutz, S. S.; Ma, T.; Mackinnon, A. J.; Malone, R. M.; Mares, D.; Marinak, M. M.; Martinson, D. D.; McKenty, P.; Meezan, N. S.; Merrill, F. E.; Moran, M. J.; Morgan, G. L.; Munson, C.; Munro, D. H.; Murphy, T. J.; Oertel, J. A.; Patel, M. V.; Polk, P. J.; Regan, S.; Roberson, G. P.; Schmidt, D. W.; Sepke, S. M.; Spears, B. K.; Tommasini, R.; Town, R.; Traille, A.; Tregillis, I. L.; Valdez, A. C.; Volegov, P. L.; Wang, T.-S. F.; Weiss, P.; Wilde, C. H.; Wilke, M. D.

    2013-11-01

    Directly laser driven and X-radiation driven DT filled capsules differ in the relationship between neutron and X-ray images. Shot N110217, a directly driven DT-filled glass micro-balloon provided the first neutron images at the National Ignition Facility. As seen in implosions on the Omega laser, the neutron image can be enclosed inside time integrated X-ray images. HYDRA simulations show the X-ray image is dominated by emission from the hot glass shell while the neutron image arises from the DT fuel it encloses. In the absence of mix or jetting, X-ray images of a cryogenically layered THD fuel capsule should be dominated by emission from the hydrogen rather than the cooler plastic shell that is separated from the hot core by cold DT fuel. This cool, dense DT, invisible in X-ray emission, shows itself by scattering hot core neutrons. Germanium X-ray emission spectra and Ross pair filtered X-ray energy resolved images suggest that germanium doped plastic emits in the torus shaped hot spot, probably reducing the neutron yield.

  2. Multidimensional modeling of type I X-ray bursts. II. Two-dimensional convection in a mixed H/He accretor

    SciTech Connect

    Malone, C. M.; Zingale, M.; Nonaka, A.; Almgren, A. S.; Bell, J. B.

    2014-06-20

    Type I X-ray bursts are thermonuclear explosions of accreted material on the surface of neutron stars in low-mass X-ray binaries. Prior to the ignition of a subsonic burning front, runaway burning at the base of the accreted layer drives convection that mixes fuel and heavy-element ashes. In this paper, the second in a series, we explore the behavior of this low Mach number convection in mixed hydrogen/helium layers on the surface of a neutron star using two-dimensional simulations with the Maestro code. Maestro takes advantage of the highly subsonic flow field by filtering dynamically unimportant sound waves while retaining local compressibility effects, such as those due to stratification and energy release from nuclear reactions. In these preliminary calculations, we find that the rp-process approximate network creates a convective region that is split into two layers. While this splitting appears artificial due to the approximations of the network regarding nuclear flow out of the breakout reaction {sup 18}Ne(α, p){sup 21}Na, these calculations hint at further simplifications and improvements of the burning treatment for use in subsequent calculations in three dimensions for a future paper.

  3. Two new Cu(ii) and La(iii) 2D coordination polymers, synthesis and in situ structural analysis by X-ray diffraction.

    PubMed

    Lundvall, F; Wragg, D S; Dietzel, P D C; Fjellvåg, H

    2016-08-01

    Two new coordination polymers were synthesized solvothermally using 4,4'-dimethoxy-3,3'-biphenyldicarboxylic acid (H2dmbpdc), and di- and trivalent metal salts (Cu(NO3)2·2.5H2O and La(NO3)3·6H2O). Their structures were determined by single-crystal X-ray diffraction analysis, and their thermal stability was evaluated by thermogravimetric analysis. The copper compound Cu(dmbpdc)(DMF; N,N-dimethylformamide), CPO-71-Cu, is based on the well known copper acetate paddlewheel secondary building unit. The asymmetric unit comprises one copper cation with one DMF molecule and one linker molecule coordinated. The lanthanum compound La2(dmbpdc)3(DMF)(H2O)3, CPO-72-La, is formed from a dimer of nine-coordinate, edge sharing lanthanum cations. To this dimer, three water molecules and one DMF molecule are coordinated in an ordered fashion. In addition, the asymmetric unit contains three crystallographically unique linker molecules. Both CPO-71-Cu and CPO-72-La form two-dimensional layered structures, and topological analyses reveal sql topologies with point symbol 4(4)·6(2) and vertex symbol 4·4·4·4·6(2)·6(2). The thermal behavior of CPO-71-Cu was investigated in an in situ structural analysis by variable temperature powder- and single-crystal X-ray diffraction. PMID:27469613

  4. Synthesis and X-ray structure analysis of a new binuclear Schiff base Co(II) complex with the ligand N,N'-bis(3-methoxysalicylidene)-1,4-butanediamine

    SciTech Connect

    Nasr-Esfahani, M.

    2009-12-15

    The title binuclear complex, tris[N,N-bis(3-methoxysalicylidene)-1,4-diaminobutane] dicobalt(II), C{sub 60}H{sub 70}Co{sub 2}N{sub 6}O{sub 15}, was prepared by the reaction of the tetradentate Schiff base ligand bis(3-methoxysalicylidene)-1,4-diaminobutane and Co(CH{sub 3}COO){sub 2} . 4H{sub 2}O in a ethanol solution and structurally characterized by single-crystal X-ray diffraction. This complex has a dinuclear structure where two Co(II) ions are bridged by one N{sup 0},N'-bis(3-methoxysalicylidene)-1,4-diaminobutane. The two Co(II) ions, have two distorted octahedral coordination involving two O and two N atoms.

  5. X-ray microtomographic scanners

    SciTech Connect

    Syryamkin, V. I. Klestov, S. A.

    2015-11-17

    The article studies the operating procedures of an X-ray microtomographic scanner and the module of reconstruction and analysis 3D-image of a test sample in particular. An algorithm for 3D-image reconstruction based on image shadow projections and mathematical methods of the processing are described. Chapter 1 describes the basic principles of X-ray tomography and general procedures of the device developed. Chapters 2 and 3 are devoted to the problem of resources saving by the system during the X-ray tomography procedure, which is achieved by preprocessing of the initial shadow projections. Preprocessing includes background noise removing from the images, which reduces the amount of shadow projections in general and increases the efficiency of the group shadow projections compression. In conclusion, the main applications of X-ray tomography are presented.

  6. Imaging X-ray spectrometer

    NASA Technical Reports Server (NTRS)

    Grant, P. A.; Jackson, J. W., Jr.; Alcorn, G. E.; Marshall, F. E. (Inventor)

    1984-01-01

    An X-ray spectrometer for providing imaging and energy resolution of an X-ray source is described. This spectrometer is comprised of a thick silicon wafer having an embedded matrix or grid of aluminum completely through the wafer fabricated, for example, by thermal migration. The aluminum matrix defines the walls of a rectangular array of silicon X-ray detector cells or pixels. A thermally diffused aluminum electrode is also formed centrally through each of the silicon cells with biasing means being connected to the aluminum cell walls and causes lateral charge carrier depletion between the cell walls so that incident X-ray energy causes a photoelectric reaction within the silicon producing collectible charge carriers in the form of electrons which are collected and used for imaging.

  7. X-ray fiducial foils

    SciTech Connect

    Alford, C.; Serduke, F.; Makowiecki, D.; Jankowski, A.; Wall, M.

    1991-03-13

    An x-ray spectrum from a laser fusion experiment was passed through an Al, Si, Y multilayer foil. The position of the absorption edges of the Al, Si, and Y was used to calibrate the x-ray energy spectrum recorded on photographic film. The foil consisted of 4000 {angstrom} of Al, 6000 {angstrom} of Si and 4000 {angstrom} of Y sputter deposited on a 1.5 {mu}m thick Mylar{reg sign} film. It was necessary to layer the structure in order to achieve the required mechanical strength and dimensional stability. The results include analysis of the x-ray energy spectrum and microstructural characterization of the foil using x-ray diffraction and transmission electron microscopy.

  8. Bone X-Ray (Radiography)

    MedlinePlus

    ... bone x-ray is used to: diagnose fractured bones or joint dislocation. demonstrate proper alignment and stabilization of bony fragments following treatment of a fracture. guide orthopedic surgery, ...

  9. X-Ray Imaging System

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Model 60007A InnerView Real-time X-ray Imaging System, produced by National Imaging Systems, a division of FlouroScan Imaging Systems, Inc. (formerly HealthMate, Inc.), Northbrook, IL, is a third generation spinoff from x-ray astronomy technology. Goddard Space Flight Center developed the original technology into the Lixiscope, a small, portable, minimal radiation x-ray instrument that could be used at the scene of an accident. FlouroScan Imaging Systems, Inc., adapted this technology to develop the FlouroScan, a low-intensity, x-ray system that could be used without the lead aprons, film badges and lead-lined walls that conventional systems require. The InnerView is a spinoff of non-destructive testing and product inspection.

  10. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Bell, Perry M.; Robinson, Ronald B.

    2000-01-01

    A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

  11. Abdomen X-Ray (Radiography)

    MedlinePlus

    ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. top ...

  12. X-Ray Exam: Finger

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... Results A radiologist, a doctor specially trained in reading and interpreting X-ray images, will look at ...

  13. X-Ray Exam: Hip

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of keeping still while the X-ray is ...

  14. X-Ray Exam: Foot

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of staying still while the X-ray is ...

  15. X-Ray Exam: Ankle

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of staying still while the X-ray is ...

  16. X-Ray Exam: Pelvis

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of keeping still while the X-ray is ...

  17. X-Ray Exam: Forearm

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of staying still while the X-ray is ...

  18. X-Ray Exam: Wrist

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of staying still while the X-ray is ...

  19. Exploring X-ray and radio emission of type 1 AGN up to z ~ 2.3

    NASA Astrophysics Data System (ADS)

    Ballo, L.; Heras, F. J. H.; Barcons, X.; Carrera, F. J.

    2012-09-01

    Context. X-ray emission from active galactic nuclei (AGN) is dominated by the accretion disk around a supermassive black hole. The radio luminosity, however, has not such a clear origin except in the most powerful sources where jets are evident. The origin (and even the very existence) of the local bi-modal distribution in radio-loudness is also a debated issue. Aims: By analysing X-ray, optical and radio properties of a large sample of type 1 AGN and quasars (QSOs) up to z > 2, where the bulk of this population resides, we aim to explore the interplay between radio and X-ray emission in AGN, in order to further our knowledge on the origin of radio emission, and its relation to accretion. Methods: We analyse a large (~800 sources) sample of type 1 AGN and QSOs selected from the 2XMMi XMM-Newton X-ray source catalogue, cross-correlated with the SDSS DR7 spectroscopic catalogue, covering a redshift range from z ~ 0.3 to z ~ 2.3. Supermassive black hole masses are estimated from the Mg ii emission line, bolometric luminosities from the X-ray data, and radio emission or upper limits from the FIRST catalogue. Results: Most of the sources accrete close to the Eddington limit and the distribution in radio-loudness does not appear to have a bi-modal behaviour. We confirm that radio-loud AGN are also X-ray loud, with an X-ray-to-optical ratio up to twice that of radio-quiet objects, even excluding the most extreme strongly jetted sources. By analysing complementary radio-selected control samples, we find evidence that these conclusions are not an effect of the X-ray selection, but are likely a property of the dominant QSO population. Conclusions: Our findings are best interpreted in a context where radio emission in AGN, with the exception of a minority of beamed sources, arises from very close to the accretion disk and is therefore heavily linked to X-ray emission. We also speculate that the radio-loud/radio-quiet dichotomy might either be an evolutionary effect that

  20. Electromechanical x-ray generator

    DOEpatents

    Watson, Scott A; Platts, David; Sorensen, Eric B

    2016-05-03

    An electro-mechanical x-ray generator configured to obtain high-energy operation with favorable energy-weight scaling. The electro-mechanical x-ray generator may include a pair of capacitor plates. The capacitor plates may be charged to a predefined voltage and may be separated to generate higher voltages on the order of hundreds of kV in the AK gap. The high voltage may be generated in a vacuum tube.