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Sample records for chandra acis ccds

  1. Chandra ACIS Observations of Jovian X-Ray Emission

    Science.gov (United States)

    Garmire, Gordon; Elsner, Ronald; Feigelson, Eric; Ford, Peter; Gladstone, G. Randall; Hurley, Kevin; Metzger, Albert; Waite, J. Hunter, Jr.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    On November 25 and 26, 1999, the Chandra X-ray spacecraft conducted a set of four 19,000 sec observations of Jupiter. The ACIS-S instrument configuration was used for its good low energy efficiency and spatial resolution. An anomalous response was obtained which was subsequently attributed to strong jovian infrared radiation penetrating the detector and piling up spurious events across the entire X-ray range. However, the pre-observation establishment of an offsetting bias field has allowed the recovery of data from that portion of Jupiter's disc which remained within the elevated portion of the bias field during the observation. This ranges from fewer than 3000 sec to the entire observing time for about 10% of the planet. Auroral emission is seen near both poles in each observation. The northern aurora ia overall more intense than the southern, consistent with prior Einstein and ROSAT Observatory results. The southern aurora shows more modulation with Jupiter's rotation than the northern. Spatial resolution has been improved by at least a factor of two over prior measurements but convincing evidence of structure has not been seen. Lower latitude emission, first observed by ROSAT, is confirmed with flux levels averaging more than a factor of five below peak auroral values. Pronounced variation in the observed emission has occurred over the observing period. The spectral response extends from 0.24 keV, below which noise dominates, to about 1.2 keV. For all four observations the spectrum is clearly enhanced between 0.45 and 0.85 keV. This is apparently unequivocal evidence that Jupiter's X-ray emission is the result of oxygen and perhaps sulfur ions precipitating into the planet's atmosphere, where they undergo charge exchange interactions. The identification of specific transitions lines in the spectrum is among the ongoing efforts. A bremsstrahlung component has not yet been identified.

  2. Annealing bounds to prevent further Charge Transfer Inefficiency increase of the Chandra X-ray CCDs

    Energy Technology Data Exchange (ETDEWEB)

    Monmeyran, Corentin, E-mail: comonmey@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Patel, Neil S., E-mail: neilp@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Bautz, Mark W., E-mail: mwb@space.mit.edu [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Grant, Catherine E., E-mail: cgrant@space.mit.edu [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Prigozhin, Gregory Y., E-mail: gyp@space.mit.edu [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Agarwal, Anuradha, E-mail: anu@mit.edu [Microphotonics Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Kimerling, Lionel C., E-mail: lckim@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Microphotonics Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2016-12-15

    After the front-illuminated CCDs on board the X-ray telescope Chandra were damaged by radiation after launch, it was decided to anneal them in an effort to remove the defects introduced by the irradiation. The annealing led to an unexpected increase of the Charge Transfer Inefficiency (CTI). The performance degradation is attributed to point defect interactions in the devices. Specifically, the annealing at 30 °C activated the diffusion of the main interstitial defect in the device, the carbon interstitial, which led to its association with a substitutional impurity, ultimately resulting in a stable and electrically active defect state. Because the formation reaction of this carbon interstitial and substitutional impurity associate is diffusion limited, we recommend a higher upper bound for the annealing temperature and duration of any future CCD anneals, that of −50 °C for one day or −60 °C for a week, to prevent further CTI increase.

  3. VizieR Online Data Catalog: Chandra ACIS survey in nearby galaxies. II (Wang+, 2016)

    Science.gov (United States)

    Wang, S.; Qiu, Y.; Liu, J.; Bregman, J. N.

    2018-03-01

    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{\\sim}1.50{\\pm}0.07) to elliptical ({\\sim}1.21{\\pm}0.02), to spirals ({\\sim}0.80{\\pm}0.02), to peculiars ({\\sim}0.55{\\pm}0.30), and to irregulars ({\\sim}0.26{\\pm}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 D25 and 2D25, 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{\\pm}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 4x1040erg/s, and this break may suggest a mild boundary between the stellar black hole population possibly including 30M{\\sun} black holes with super-Eddington radiation and intermediate mass black holes. (1 data file).

  4. Chandra ACIS Survey of M33 (ChASeM33): Spectral and Timing Analysis of the 15 Brightest Sources

    Science.gov (United States)

    Plucinsky, Paul P.; Tuellmann, R.; Gaetz, T. J.; Challis, P.; Kirshner, R. P.; Williams, B. F.; Kuntz, K. D.; ChASeM33 Team

    2011-01-01

    The Chandra ACIS Survey of M33 (ChASeM33) is the deepest X-ray survey to date of M33. ChASeM33 covers about 70% of the D25 isophote (R 4.0 kpc) with a total exposure of 1.4 Ms. The source catalog includes 662 sources, reaching a limiting sensitivity of 2.0e34 erg/s in the 0.35--8.0 keV energy band. There are fifteen sources in the catalog with more than 2,000 net counts, allowing detailed spectral and timing analyses to be conducted. We report here the results of fitting these spectra with multi-component disk blackbody, power-law, and/or thermal plasma models. We also report on the short-term (within an observation) and long-term (from one observation to another) variability of these sources. These X-ray spectral and timing results in conjunction with optical spectroscopy for some of the sources, allow us to classify the objects. Six of the sources are X-ray Binaries (3 certain/3 most likely), 3 are Supernova Remnants (all three certain), and 6 are Active Galactic Nuclei (3 certain/3 most likely). The faintest of these sources has a flux (0.35-8.0 keV) of 3.5e-14 ergs/(s cm2) and an inferred luminosity of 3.0e36 ergs/s (0.35-8.0 keV) at the distance of M33. We comment on the contribution of these ``background'' sources to studies of the X-ray source populations in galaxies. This work was supported by NASA grant NAS G06-7073A and NASA contract NAS8-03060.

  5. Modeling Contamination Migration on the Chandra X-Ray Observatory - III

    Science.gov (United States)

    O'Dell, Stephen L.; Swartz, Douglas A.; Tice, Neil W.; Plucinsky, Paul P.; Grant, Catherine E.; Marshall, Herman L.; Vikhlinin, Alexy A.; Tennant, Allyn F.; Dahmer, Matthew T.

    2015-01-01

    During its first 16 years of operation, the cold (about -60 C) 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, in part to evaluate potential bake-out scenarios intended to reduce the level of contamination. Keywords: X-ray astronomy, CCDs, contamination, modeling and simulation, spacecraft operations

  6. Toward Fast, Low-noise, Low-power, Small Pixel Digital CCDs for X-ray Astronomy

    Science.gov (United States)

    Bautz, Mark W.; Burke, Barry; Cooper, Michael; Foster, Richard; Grant, Catherine E.; LaMarr, Beverly; Malonis, Andrew; Miller, Eric D.; Prigozhin, Gregory; Schuette, Daniel

    2017-08-01

    Future X-ray missions such as Lynx will require large-format imaging detectors with spectroscopic performance at least as good as the best current-generation devices but with much higher readout rates. We have been investigating a detector architecture under development at MIT Lincoln Laboratory, called the Digital CCD, for use in such missions. The Digital CCD is envisioned as a CMOS-compatible detector integrated with parallel CMOS signal processing chains. The combination of fast, low noise CCD amplifiers with highly parallel signal processing offers the high frame-rate required. The CMOS-compatibility of the CCD provides low-power charge transfer.Here we report on the X-ray spectral response of a CMOS-compatible test CCD read at 2.5 MHz (about 25 times faster than the CCDs operating on Chandra ACIS), using transfer clock levels of only +-1 V (power per unit area less than 25 times that of ACIS CCDs). The 8-micron pixels of this device are one third the size of those on Chandra ACIS. We compare charge splitting in this detector with that observed in larger-pixel detectors, and we briefly discuss the implications of the small-pixel, deep-depletion detector configurations required by Lynx.

  7. Real Time Space Weather Support for Chandra X-Ray Observatory Operations

    Science.gov (United States)

    O'Dell, Stephen L.; Minow, Joseph I.; Miller, J. Scott; Wolk, Scott J.; Aldcroft, Thomas L.; Spitzbart, Bradley D.; Swartz. Douglas A.

    2012-01-01

    NASA launched the Chandra X-ray Observatory in July 1999. Soon after first light in August 1999, however, degradation in the energy resolution and charge transfer efficiency of the Advanced CCD Imaging Spectrometer (ACIS) x-ray detectors was observed. The source of the degradation was quickly identified as radiation damage in the charge-transfer channel of the front-illuminated CCDs, by weakly penetrating ( soft , 100 500 keV) protons as Chandra passed through the Earth s radiation belts and ring currents. As soft protons were not considered a risk to spacecraft health before launch, the only on-board radiation monitoring system is the Electron, Proton, and Helium Instrument (EPHIN) which was included on Chandra with the primary purpose of monitoring energetic solar particle events. Further damage to the ACIS detector has been successfully mitigated through a combination of careful mission planning, autonomous on-board radiation protection, and manual intervention based upon real-time monitoring of the soft-proton environment. The AE-8 and AP-8 trapped radiation models and Chandra Radiation Models are used to schedule science operations in regions of low proton flux. EPHIN has been used as the primary autonomous in-situ radiation trigger; but, it is not sensitive to the soft protons that damage the front-illuminated CCDs. Monitoring of near-real-time space weather data sources provides critical information on the proton environment outside the Earth s magnetosphere due to solar proton events and other phenomena. The operations team uses data from the Geostationary Operational Environmental Satellites (GOES) to provide near-real-time monitoring of the proton environment; however, these data do not give a representative measure of the soft-proton (Space Weather Prediction Center. This presentation describes the radiation mitigation strategies to minimize the proton damage in the ACIS CCD detectors and the importance of real-time data sources that are used to protect

  8. Chandra ACIS-S imaging spectroscopy of anomalously faint X-ray emission from Comet 103P/Hartley 2 during the EPOXI encounter

    Science.gov (United States)

    Lisse, C. M.; Christian, D. J.; Wolk, S. J.; Dennerl, K.; Bodewits, D.; Combi, M. R.; Lepri, S. T.; Zurbuchen, T. H.; Li, J. Y.; Dello-Russo, N.; Belton, M. J. S.; Knight, M. M.

    2013-02-01

    We present results from the Chandra X-ray Observatory's characterization of the X-ray emission from Comet 103P/Hartley 2, in support of NASA's Deep Impact Extended close flyby of the comet on 04 November 2010. The comet was observed 4 times for a total on target time of ˜60 ks between the 17th of October and 16th of November 2010, with two of the visits occurring during the EPOXI close approach on 04 November and 05 November 2010. X-ray emission from 103P was qualitatively similar to that observed for collisionally thin Comets 2P/Encke (Lisse, C.M. et al. [2005]. Astrophys. J. 635, 1329-1347) and 9P/Tempel 1 (Lisse, C.M. et al. [2007]. Icarus 190, 391-405). Emission morphology offset sunward but asymmetrical from the nucleus and emission lines produced by charge exchange between highly stripped C, N, and O solar wind minor ions and coma neutral gas species were found. The comet was very under-luminous in the X-ray at all times, representing the 3rd faintest comet ever detected (LX = 1.1 ± 0.3 × 1014 erg s-1). The coma was collisionally thin to the solar wind at all times, allowing solar wind ions to flow into the inner coma and interact with the densest neutral coma gas. Localization of the X-ray emission in the regions of the major rotating gas jets was observed, consistent with the major source of cometary neutral gas species being icy coma dust particles. Variable spectral features due to changing solar wind flux densities and charge states were also seen. Modeling of the Chandra observations from the first three visits using observed gas production rates and ACE solar wind ion fluxes with a charge exchange mechanism for the emission is consistent with the temporal and spectral behavior expected for a slow, hot wind typical of low latitude emission from the solar corona interacting with the comet's neutral coma. The X-ray emission during the 4th visit on 16 November 2010 is similar to the unusual behavior seen for Comet 17P/Holmes in 2007 (Christian, D.J. et

  9. CTIO, ROSAT HRI, and Chandra ACIS Observations of the Archetypical Mixed-morphology Supernova Remnant W28 (G6.4–0.1)

    International Nuclear Information System (INIS)

    Pannuti, Thomas G.; Kosakowski, Alekzander R.; Ernst, Sonny; Rho, Jeonghee; Kargaltsev, Oleg; Rangelov, Blagoy; Hare, Jeremy; Winkler, P. Frank; Keohane, Jonathan W.

    2017-01-01

    We present a joint analysis of optical emission-line and X-ray observations of the archetypical Galactic mixed-morphology supernova remnant (MMSNR) W28 (G6.4–0.1). MMSNRs comprise a class of sources whose shell-like radio morphology contrasts with a filled center in X-rays; the origin of these contrasting morphologies remains uncertain. Our CTIO images reveal enhanced [S ii] emission relative to H α along the northern and eastern rims of W28. Hydroxyl (OH) masers are detected along these same rims, supporting prior studies suggesting that W28 is interacting with molecular clouds at these locations, as observed for several other MMSNRs. Our ROSAT HRI mosaic of W28 provides almost complete coverage of the supernova remnant (SNR). The X-ray and radio emission is generally anti-correlated, except for the luminous northeastern rim, which is prominent in both bands. Our Chandra observation sampled the X-ray-luminous central diffuse emission. Spectra extracted from the bright central peak and from nearby annular regions are best fit with two overionized recombining plasma models. We also find that while the X-ray emission from the central peak is dominated by swept-up material, that from the surrounding regions shows evidence for oxygen-rich ejecta, suggesting that W28 was produced by a massive progenitor. We also analyze the X-ray properties of two X-ray sources (CXOU J175857.55−233400.3 and 3XMM J180058.5–232735) projected into the interior of W28 and conclude that neither is a neutron star associated with the SNR. The former is likely to be a foreground cataclysmic variable or a quiescent low-mass X-ray-binary, while the latter is likely to be a coronally active main-sequence star.

  10. CTIO, ROSAT HRI, and Chandra ACIS Observations of the Archetypical Mixed-morphology Supernova Remnant W28 (G6.4–0.1)

    Energy Technology Data Exchange (ETDEWEB)

    Pannuti, Thomas G.; Kosakowski, Alekzander R.; Ernst, Sonny [Space Science Center, Department of Earth and Space Sciences, Morehead State University, 235 Martindale Drive, Morehead, KY 40351 (United States); Rho, Jeonghee [SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Kargaltsev, Oleg; Rangelov, Blagoy; Hare, Jeremy [Department of Physics, 214 Samson Hall, George Washington University, Washington, D.C. 20052 (United States); Winkler, P. Frank [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States); Keohane, Jonathan W., E-mail: t.pannuti@moreheadstate.edu, E-mail: jrho@seti.org, E-mail: jrho@sofia.usra.edu, E-mail: kargaltsev@gwu.edu, E-mail: alekzanderkos@ou.edu, E-mail: winkler@middlebury.edu, E-mail: jkeohane@hsc.edu [Department of Physics and Astronomy, Hampden-Sydney College, Hampden-Sydney, VA 23943 (United States)

    2017-04-10

    We present a joint analysis of optical emission-line and X-ray observations of the archetypical Galactic mixed-morphology supernova remnant (MMSNR) W28 (G6.4–0.1). MMSNRs comprise a class of sources whose shell-like radio morphology contrasts with a filled center in X-rays; the origin of these contrasting morphologies remains uncertain. Our CTIO images reveal enhanced [S ii] emission relative to H α along the northern and eastern rims of W28. Hydroxyl (OH) masers are detected along these same rims, supporting prior studies suggesting that W28 is interacting with molecular clouds at these locations, as observed for several other MMSNRs. Our ROSAT HRI mosaic of W28 provides almost complete coverage of the supernova remnant (SNR). The X-ray and radio emission is generally anti-correlated, except for the luminous northeastern rim, which is prominent in both bands. Our Chandra observation sampled the X-ray-luminous central diffuse emission. Spectra extracted from the bright central peak and from nearby annular regions are best fit with two overionized recombining plasma models. We also find that while the X-ray emission from the central peak is dominated by swept-up material, that from the surrounding regions shows evidence for oxygen-rich ejecta, suggesting that W28 was produced by a massive progenitor. We also analyze the X-ray properties of two X-ray sources (CXOU J175857.55−233400.3 and 3XMM J180058.5–232735) projected into the interior of W28 and conclude that neither is a neutron star associated with the SNR. The former is likely to be a foreground cataclysmic variable or a quiescent low-mass X-ray-binary, while the latter is likely to be a coronally active main-sequence star.

  11. Gamma noise in CCDs

    International Nuclear Information System (INIS)

    Autio, G.W.; Bafico, M.A.

    1975-01-01

    The overall results indicated that charge coupled devices (CCD) used to read out detector signals or as signal processing electronics in future space sensors can operate real time in a high ionising radiation environment. Future work should be directed towards hardening the CCDs during the fabrication processes in order that they may survive total radiation doses up to 1 x 10 6 Rad (Si) and toward investigating ionising radiation effects in CCDs that are coupled with i.r. detectors. CCD devices employed to read out detector signals can be made capable of handling radiation induced excess noise and high false alarm rates generated in the detector elements. Ionising radiation effects induced in the detectors are expected to dominate those generated directly in the CCD readout structure; how much depends on the relative size of the detector. The low frequency γ induced excess noise measured in the CCD/MOSFET structure could cause problems for space sensors required to operate in real time only at the very high γ flux levels. Discrimination and circumvention techniques at the CCD ERO output are possible. γ pulses measured at the CCD ERO output were distributed in amplitude and exhibited variable pulse widths (some were many times a clock period). (author)

  12. High-voltage-compatible, fully depleted CCDs

    Energy Technology Data Exchange (ETDEWEB)

    Holland, Stephen E.; Bebek, Chris J.; Dawson, Kyle S.; Emes, JohnE.; Fabricius, Max H.; Fairfield, Jessaym A.; Groom, Don E.; Karcher, A.; Kolbe, William F.; Palaio, Nick P.; Roe, Natalie A.; Wang, Guobin

    2006-05-15

    We describe charge-coupled device (CCD) developmentactivities at the Lawrence Berkeley National Laboratory (LBNL).Back-illuminated CCDs fabricated on 200-300 mu m thick, fully depleted,high-resistivity silicon substrates are produced in partnership with acommercial CCD foundry.The CCDs are fully depleted by the application ofa substrate bias voltage. Spatial resolution considerations requireoperation of thick, fully depleted CCDs at high substrate bias voltages.We have developed CCDs that are compatible with substrate bias voltagesof at least 200V. This improves spatial resolution for a given thickness,and allows for full depletion of thicker CCDs than previously considered.We have demonstrated full depletion of 650-675 mu m thick CCDs, withpotential applications in direct x-ray detection. In this work we discussthe issues related to high-voltage operation of fully depleted CCDs, aswell as experimental results on high-voltage-compatible CCDs.

  13. Spectral analysis of the Chandra comet survey

    NARCIS (Netherlands)

    Bodewits, D.; Christian, D. J.; Torney, M.; Dryer, M.; Lisse, C. M.; Dennerl, K.; Zurbuchen, T. H.; Wolk, S. J.; Tielens, A. G. G. M.; Hoekstra, R.

    Aims. We present results of the analysis of cometary X-ray spectra with an extended version of our charge exchange emission model (Bodewits et al. 2006). We have applied this model to the sample of 8 comets thus far observed with the Chandra X-ray observatory and acis spectrometer in the 300 - 1000

  14. VizieR Online Data Catalog: Chandra observations of IC 10 (Laycock+, 2017)

    Science.gov (United States)

    Laycock, S.; Cappallo, R.; Williams, B. F.; Prestwich, A.; Binder, B.; Christodoulou, D. M.

    2017-09-01

    A monitoring series of 7x15ks Chandra/ACIS observations, spaced at roughly six-week intervals was obtained during 2009-2010. A pair of very deep ACIS-S3 observations (2x45ks) made in 2006 November provide a reference data set for improved source positions and spectral information. The original Wang+ (2005, J/MNRAS/362/1065) Chandra (ACIS-S3) observation of 30ks made in 2003 was included in our analysis. The complete listing of 10 observation identifiers (ObsIDs) comprising the data set is summarized in Table 1. (5 data files).

  15. Characterization of Prototype LSST CCDs

    Energy Technology Data Exchange (ETDEWEB)

    OCONNOR,P.; FRANK, J.; GEARY, J.C.; GILMORE, D.K.; KOTOV, I.; RADEKA, V.; TAKACS, P.; TYSON, J.A.

    2008-06-23

    a number of new devices produced specifically to address LSST's performance goals, including flatness, QE, PSF, dark current, read noise, CTE, cosmetics, and crosstalk. The results indicate that commercially produced, thick n-channel over-depleted CCDs with excellent red response can achieve tight PSF at moderate applied substrate bias with no evidence of persistent image artifacts. We will also report ongoing studies of mosaic assembly techniques to achieve chip-to-chip co-planarity, high fill factor, and thermal stability.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  18. Chandra Observations of Starburst Galaxies

    Science.gov (United States)

    Prestwich, Andrea; Lavoie, Anthony R. (Technical Monitor)

    2000-01-01

    We present early X-ray results from Chandra for two starburst galaxies, M82 and NGC3256, obtained using AXAF CCD Imaging Spectrometer (ACIS-I) and the HRC. For M82 the arcsecond spatial resolution enables us to separate the point source component from the extended emission for the first time. Astrometry reveals that most of the X-ray sources are not coincident with the family of compact radio sources believed to be Super Nova Remnants (SNRs). In addition, based on three epoch Chandra observations, several of the X-ray sources are clearly variable indicating that they are binaries. When we deconvolve the extended and point source components detected in the hard X-ray band, we find that 50 percent arises from the extended component. This fact, together with its morphology, constrains the various models proposed to explain the hard X-ray emission. For NGC3256 we resolve two closely separated nuclei. These new data support a pure starburst origin for the total X-ray emission rather than a composite AGN/starburst, thereby making NGC3256 one of the most X-ray luminous starburst galaxies known.

  19. XMM-Newton and Chandra Observations of the Galaxy Group NGC 5044. 1; Evidence for Limited Multiphase Hot Gas

    Science.gov (United States)

    Buote, David A.; Lewis, Aaron D.; Brighenti, Fabrizio; Mathews, William G.

    2003-01-01

    Using new XMM and Chandra observations, we present an analysis of the temperature structure of the hot gas within a radius of 100 kpc of the bright nearby galaxy group NGC 5044. A spectral deprojection analysis of data extracted from circular annuli reveals that a two-temperature model (2T) of the hot gas is favored over single-phase or cooling flow (M = 4.5 +/- 0.2 solar mass/yr) models within the central approx.30 kpc. Alternatively, the data can be fitted equally well if the temperature within each spherical shell varies continuously from approx.T(sub h) to T(sub c) approx. T(sub h)/2, but no lower. The high spatial resolution of the Chandra data allows us to determine that the temperature excursion T(sub h) approaches T(sub c) required in each shell exceeds the temperature range between the boundaries of the same shell in the best-fitting single-phase model. This is strong evidence for a multiphase gas having a limited temperature range. We do not find any evidence that azimuthal temperature variations within each annulus on the sky can account for the range in temperatures within each shell. We provide a detailed investigation of the systematic errors on the derived spectral models considering the effects of calibration, plasma codes, bandwidth, variable NH, and background rate. We find that the RGS gratings and the EPIC and ACIS CCDs give fully consistent results when the same models are fitted over the same energy ranges for each instrument. The cooler component of the 2T model has a temperature (T(sub c) approx. 0.7 keV) similar to the kinetic temperature of the stars. The hot phase has a temperature (T(sub h) approx. 1.4 keV) characteristic of the virial temperature of the solar mass halo expected in the NGC 5044 group. However, in view of the morphological disturbances and X-ray holes visible in the Chandra image within R approx. equals 10 kpc, bubbles of gas heated to approx.T(sub h) in this region may be formed by intermittent AGN feedback. Some

  20. Shelter from the Storm: Protecting the Chandra X-ray Observatory from Radiation

    Science.gov (United States)

    Cameron, Robert A.; Morris, David C.; Virani, Shanil N.; Wolk, Scott J.; Blackwell, William C.; Minow, Joseph I.; O'dell, Stephen L.

    NASA's Chandra X-ray Observatory was launched in July 1999, and the first images were recorded by the ACIS x-ray detector in August 1999. Shortly after first light, degradation of the energy resolution and charge transfer efficiency in the ACIS CCD detectors was observed, and this was quickly attributed to cumulative particle radiation damage in the CCD's, in particular from 100 keV to 200 keV protons. Since the onset of this radiation damage to ACIS, several improvements have been made to autonomous Chandra operation and ground-based operations and mission planning, to limit the effects of radiation while preserving optimum observing efficiency for the Observatory. These changes include implementing an automatic science instrument radiation protection system on Chandra, implementing a real-time radiation monitoring and alert system by the Science Operations Team, and improving the radiation prediction models used in mission planning for the Observatory. These satellite- and ground-based systems provide protection for Chandra from passages through the Earth's trapped radiation belts and outer magnetosphere and from flares and coronal mass ejections from the Sun. We describe the design and performance of the automatic on-board radiation protection system on Chandra, and the ground-based software systems and data products for real-time radiation monitoring. We also describe the development and characterize the performance of the Chandra Radiation Model (CRM), which provides predictions of the solar wind and magnetospheric proton fluxes along Chandra's orbit, indexed by the geomagnetic activity index, Kp. We compare the observed and predicted damage rates to ACIS based on net mission proton fluence, and outline planned enhancements to the CRM.

  1. Precision Astronomy with Imperfect Deep Depletion CCDs

    Science.gov (United States)

    Stubbs, Christopher; LSST Sensor Team; PanSTARRS Team

    2014-01-01

    While thick CCDs do provide definite advantages in terms of increased quantum efficiency at wavelengths 700 nmlateral electrical fields within the detector, that produce charge transport anomalies that have been previously misinterpreted as quantum efficiency variations. Performing simplistic flat-fielding therefore introduces systematic errors in the image processing pipeline. One measurement challenge we face is devising a combination of calibration methods and algorithms that can distinguish genuine quantum efficiency variations from charge transport effects. These device imperfections also confront spectroscopic applications, such as line centroid determination for precision radial velocity studies. Given the scientific benefits of improving both the precision and accuracy of astronomical measurements, we need to identify, characterize, and overcome these various detector artifacts. In retrospect, many of the detector features first identified in thick CCDs also afflict measurements made with more traditional CCD detectors, albeit often at a reduced level since the photocharge is subject to the perturbing influence of lateral electric fields for a shorter time interval. I provide a qualitative overview of the physical effects we think are responsible for the observed device properties, and provide some perspective for the work that lies ahead.

  2. Frameworks for ACI: Animals as Stakeholders in the Design Process

    OpenAIRE

    North, Steve; Mancini, Clara

    2016-01-01

    Animal-computer interaction (ACI) is an emerging discipline concerned with studying the relationship between animals and technology, designing interactive technology to support animals, and developing methodologies that can enable animals to participate in the design process as legitimate stakeholders. By welcoming animals to the design table, ACI is delineating new frontiers for interaction design. However, if co-designing HCI artifacts is already fraught with misunderstanding, how might ACI...

  3. Pramod Chandra P Bhatt

    Indian Academy of Sciences (India)

    Introduction to Web Information Retrieval: A User Perspective - How to get what you want on the World Wide Web · Srinath Srinivasa Pramod Chandra P Bhatt · More Details Fulltext PDF. Volume 17 Issue 8 August 2012 pp 727-747 General Article. UNIX: Genesis and Design Features · Pramod Chandra P Bhatt.

  4. chandra s sharma

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. CHANDRA S SHARMA. Articles written in Bulletin of Materials Science. Volume 40 Issue 7 December 2017 pp 1519-1527. Low temperature catalyst-assisted pyrolysis of polymer precursors to carbon · RAMYA ARAGA SURESH KALI CHANDRA S SHARMA · More Details ...

  5. Chandra's X-ray Vision

    Indian Academy of Sciences (India)

    1999-07-23

    Jul 23, 1999 ... GENERAL I ARTICLE. Chandra's X-ray Vision. K P Singh. Chandra X-ray Observatory (CXO) is a scientific satellite (moon/ chandra), named after the Indian-born Nobel laureate. Subrahmanyan Chandrasekhar - one of the foremost astro- physicists of the twentieth century and popularly known as. Chandra.

  6. 500 MHz transient digitizers based on GaAs CCDs

    International Nuclear Information System (INIS)

    Bryman, D.A.; Constable, M.; Cresswell, J.V.; Daviel, A.; LeNoble, M.; Mildenberger, J.; Poutissou, R.

    1996-11-01

    A system of 500 MHz transient digitizers based on gallium arsenide resistive gate charged coupled devices has been developed for an experiment studying rare K decays. CCDs with dynamic range of 8-bits and 128 or 320 pixels are used as analog pipelines. The CCD's are driven by a single phase transport system. Data readout and manipulation occurs at 15.6 MHz. (authors)

  7. Investigations into properties of charge traps created in CCDs by ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 69; Issue 6 ... Our group has been investigating the effects related to radiation damage of CCDs since 1998. In a series of measurements in 2003 we found the puzzling effect of very slow filling of charge traps created by radiation damage of the silicon device. In 2005 ...

  8. Investigations into properties of charge traps created in CCDs by ...

    Indian Academy of Sciences (India)

    Abstract. Our group has been investigating the effects related to radiation damage of. CCDs since 1998. In a series of measurements in 2003 we found the puzzling effect of very slow filling of charge traps created by radiation damage of the silicon device. In 2005 we intended to study this phenomenon in detail. However ...

  9. Speckle Imaging of Binary Stars with Large-Format CCDs

    Science.gov (United States)

    Horch, E.; Ninkov, Z.; Slawson, R. W.; van Altena, W. F.; Meyer, R. D.; Girard, T. M.

    1997-12-01

    In the past, bare (unintensified) CCDs have not been widely used in speckle imaging for two main reasons: 1) the readout rate of most scientific-grade CCDs is too slow to be able to observe at the high frame rates necessary to capture speckle patterns efficiently, and 2) the read noise of CCDs limits the detectability of fainter objects where it becomes difficult to distinguish between speckles and noise peaks in the image. These facts have led to the current supremacy of intensified imaging systems (such as intensified-CCDs) in this field, which can typically be read out at video rates or faster. We have developed a new approach that uses a large format CCD not only to detect the incident photons but also to record many speckle patterns before the chip is read out. This approach effectively uses the large area of the CCD as a physical ``memory cache'' of previous speckle data frames. The method is described, and binary star observations from the University of Toronto Southern Observatory 60-cm telescope and the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5-m telescope are presented. Plans for future observing and instrumentation improvements are also outlined.

  10. Point-spread function in depleted and partially depleted CCDs

    International Nuclear Information System (INIS)

    Groom, D.E.; Eberhard, P.H.; Holland, S.E.; Levi, M.E.; Palaio, N.P.; Perlmutter, S.; Stover, R.J.; Wei, M.

    1999-01-01

    The point spread function obtainable in an astronomical instrument using CCD readout is limited by a number of factors, among them the lateral diffusion of charge before it is collected in the potential wells. They study this problem both theoretically and experimentally, with emphasis on the thick CCDs on high-resistivity n-type substrates being developed at Lawrence Berkeley National Laboratory

  11. Mandal, Prof. Nitai Chandra

    Indian Academy of Sciences (India)

    Nitai Chandra Ph.D. (Calcutta), FNA, FNASc. Date of birth: 12 July 1938. Specialization: Molecular Genetics and Molecular Biology of Prokaryotes Address: E-5, Digantika, AH Block, Sector II, Salt Lake, Kolkata 700 091, W.B.. Contact: Residence: (033) 2359 1356. Mobile: 94775 85894. Email: mandalnc2003@yahoo.com.

  12. Lakhotia, Prof. Subhash Chandra

    Indian Academy of Sciences (India)

    Elected: 1994 Section: Animal Sciences. Lakhotia, Prof. Subhash Chandra Ph.D. (Calcutta), FNA, FNASc. Date of birth: 4 October 1945. Specialization: Ayurvedic Biology, Cytogenetics, Gene Expression, Stress Biology and Molecular Biology Address: INSA Senior Scientist, Department of Zoology, Banaras Hindu University ...

  13. Mishra, Dr Gyan Chandra

    Indian Academy of Sciences (India)

    Fellow Profile. Elected: 2005 Section: General Biology. Mishra, Dr Gyan Chandra Ph.D. (Udaipur), FNASc, FNA. Date of birth: 15 August 1947. Specialization: Immunology and Cell Biology Address: NASI Senior Scientist, National Centre for Cell Science, NCCS Complex, Ganeshkhind, Pune 411 007, Maharashtra Contact:

  14. Budhani, Dr Ramesh Chandra

    Indian Academy of Sciences (India)

    Budhani, Dr Ramesh Chandra Ph.D. (IIT, Delhi), FNASc, FNA. Date of birth: 3 February 1955. Specialization: Renewable Energy, Nanoscale Systems, Experimental Condensed Matter Physics, Superconductivity and Magnetism Address: Department of Physics, Lasers & Photonics, Indian Institute of Technology, Kanpur 208 ...

  15. Chance and Chandra

    Indian Academy of Sciences (India)

    today.) This unfinished business concerns the relationship between dynamical relaxation and chaos. Chandra's analysis presumes that two given particles encounter one another just once since he treats their .... scalar field and its action invariant to global phase changes, since otherwise they would have an annihilation ...

  16. Agrawal, Prof. Prahlad Chandra

    Indian Academy of Sciences (India)

    Fellow Profile. Elected: 1990 Section: Physics. Agrawal, Prof. Prahlad Chandra Ph.D. (Mumbai), FNASc. Date of birth: 15 April 1941. Specialization: X-ray Astronomy and Experimental High Energy Astrophysics Address: 405, Vigyan Scientists' CHS, Plot No. 23, Sector 17, Vashi, Navi Mumbai 400 703, Maharashtra Contact:

  17. Mehta, Prof. Chandra Lal

    Indian Academy of Sciences (India)

    Elected: 1982 Section: Physics. Mehta, Prof. Chandra Lal Ph.D. (Rochester). Date of birth: 31 July 1938. Specialization: Quantum & Statistical Optics and Mathematical Physics Address: B-43, Gyandeep Apartments, Mayur Vihar, Phase I, New Delhi 110 091, U.T.. Contact: Residence: (011) 2279 6410. Mobile: 90133 91375

  18. Karthik Raman Nagasuma Chandra

    Indian Academy of Sciences (India)

    Karthik Raman1 Nagasuma Chandra2. Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Switzerland; Bioinformatics Centre, Raman building, Indian Institute of Science, Bangalore 560 012, India. Resonance – Journal of Science Education. Current Issue : Vol. 23, Issue 2. Current Issue

  19. Venkataraman, Prof. Chandra

    Indian Academy of Sciences (India)

    Elected: 2018 Section: Earth & Planetary Sciences. Venkataraman, Prof. Chandra Ph.D. (Univ. Calif., Los Angeles), FNAE, FNASc. Date of birth: 3 June 1963. Specialization: Aerosol Science & Engineering, Environmental & Climate Science, Atmospheric Science Address: Department of Chemical Engineering, Indian ...

  20. Thakur, Dr Vikram Chandra

    Indian Academy of Sciences (India)

    Fellow Profile. Elected: 1991 Section: Earth & Planetary Sciences. Thakur, Dr Vikram Chandra Ph.D. (London). Date of birth: 15 January 1940. Specialization: Structural Geology, Tectonics of Himalayan Geology and Active Tectonics Address: 9/12 (Lane 9), Ashirwad Eclave, Dehra Dun 248 001, Uttarakhand Contact:

  1. Chaturvedi, Prof. Umesh Chandra

    Indian Academy of Sciences (India)

    Chaturvedi, Prof. Umesh Chandra M.D. (Lucknow), FRC Path. (London), FAMS, FNA, FNASc, FAAM(USA). Date of birth: 2 March 1939. Specialization: Medical Microbiology, Virology and Immunology Address: 201, Annapurna Apartments, No. 1, Bishop Rocky Street, Faizabad Road, Lucknow 226 007, U.P.. Contact:

  2. Raj Chandra Bose

    Indian Academy of Sciences (India)

    Page 1. CPMG/KA/8GE-340/2003-05. Licenced to post WPP(E) No.6. Resonance - September 2003. Raj Chandra Bose. (1901 - 1987). Registered with Registrar of Newspapers in India vide Regn. No. 66273/96. ISSN 0971-8044.

  3. Chance and Chandra

    Indian Academy of Sciences (India)

    physics pp. 107–118. Chance and Chandra. JEREMY GOODMAN. ∗ and ZACHARY SLEPIAN. Princeton University Observatory, Peyton Hall, Princeton, ..... Our current view is somewhat different. In the limit that the mean-free path is large compared to the dimensions of the bar or the core, the original argument is perhaps ...

  4. Nirab Chandra Adhikary

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. Nirab Chandra Adhikary. Articles written in Bulletin of Materials Science. Volume 37 Issue 7 December 2014 pp 1613-1624. Enhancement of proton conductivity of sulfonated polystyrene membrane prepared by plasma polymerization process · Bhabesh Kumar Nath Aziz Khan ...

  5. Khanna, Dr Navin Chandra

    Indian Academy of Sciences (India)

    Elected: 2017 Section: Medicine. Khanna, Dr Navin Chandra Ph.D. (AIIMS), FNASc. Date of birth: 1 April 1956. Specialization: Dengue Subunit Vaccine, Dengue Botanical Drug, Recombinant Proteins of Medical Use Address: International Centre for Genetic Engineering, and Biotechnology, Aruna Asaf Ali Marg, New Delhi ...

  6. Chandra, Prof. Amalendu

    Indian Academy of Sciences (India)

    Fellow Profile. Elected: 2005 Section: Chemistry. Chandra, Prof. Amalendu Ph.D. (IISc), FNA, FNASc. Date of birth: 6 October 1963. Specialization: Statistical Mechanics of Liquids & Interfaces, Classical & Quantum Simulations and Molecular Modelling Address: Professor, Department of Chemistry, Indian Institute of ...

  7. Keshab Chandra Bakshi

    Indian Academy of Sciences (India)

    . Articles written in Proceedings – Mathematical Sciences. Volume 127 Issue 1 February 2017 pp 117-132 Research Article. On Pimsner-Popa bases · Keshab Chandra Bakshi · More Details Abstract Fulltext PDF. In this paper, we examine ...

  8. The Binary Offset Effect in CCDs: an Anomalous Readout Artifact Affecting Most Astronomical CCDs in Use

    Science.gov (United States)

    Boone, Kyle Robert; Aldering, Gregory; Copin, Yannick; Dixon, Samantha; Domagalski, Rachel; Gangler, Emmanuel; Pecontal, Emmanuel; Perlmutter, Saul; Nearby Supernova Factory Collaboration

    2018-01-01

    We discovered an anomalous behavior of CCD readout electronics that affects their use in many astronomical applications, which we call the “binary offset effect”. Due to feedback in the readout electronics, an offset is introduced in the values read out for each pixel that depends on the binary encoding of the previously read-out pixel values. One consequence of this effect is that a pathological local background offset can be introduced in images that only appears where science data are present on the CCD. The amplitude of this introduced offset does not scale monotonically with the amplitude of the objects in the image, and can be up to 4.5 ADU per pixel for certain instruments. Additionally, this background offset will be shifted by several pixels from the science data, potentially distorting the shape of objects in the image. We tested 22 instruments for signs of the binary offset effect and found evidence of it in 16 of them, including LRIS and DEIMOS on the Keck telescopes, WFC3-UVIS and STIS on HST, MegaCam on CFHT, SNIFS on the UH88 telescope, GMOS on the Gemini telescopes, HSC on Subaru, and FORS on VLT. A large amount of archival data is therefore affected by the binary offset effect, and conventional methods of reducing CCD images do not measure or remove the introduced offsets. As a demonstration of how to correct for the binary offset effect, we have developed a model that can accurately predict and remove the introduced offsets for the SNIFS instrument on the UH88 telescope. Accounting for the binary offset effect is essential for precision low-count astronomical observations with CCDs.

  9. Chandra X-ray Observations of Jovian Low-latitude Emissions: Morphological, Temporal, and Spectral Characteristics

    Science.gov (United States)

    Bhardwaj, Anil; Elsner, Ronald F.; Gladstone, G. Randall; Cravens, Thomas E.; Waiate J. Hunter, Jr.; Branduardi-Raymont, Graziella; Ford, Peter

    2004-01-01

    Chandra observed X-rays from Jupiter during 24-26 February 2003 for about 40 hours with the ACIS-S and HRC-I instruments. The analysis of Jovian low-latitude "disk" Xray emissions are presented and compared with the high-latitude "auroral" emissions. We report the first Chandra ACIS-S measured X-ray spectrum (0.3-2 keV) of Jupiter's low-latitude disk The disk X-ray emission is harder and extends to higher energies than the auroral spectrum. The temporal variation in the Jovian disk X-rays is on an average consistent with those in the solar X-rays observed by GOES, and TIMED/SSE. Contrary to the auroral X-rays, the disk emissions are uniformly distributed over Jupiter; no indication of longitudinal dependence or correlation with surface magneh field strength is visible. Also, unlike the approx. 40 +/- 20 min periodic oscillations seen in the auroral X-ray emissions, the disk emissions do not show any periodic oscillations. The disk spectrum seems to be consistent with resonant and fluorescent scattering of solar X-rays by the Jovian upper atmosphere. Jupiter's disk is found to be about 50% dimmer in soft X-rays in February 2003 compared that in December 2000, which is consistent with the decrease in solar activity. No evidence of lightning-induced X-rays is seen in the Chandra X-ray data. The Jovian disk spectra observed with Chandra-ACIS is stronger than that observed with XMM-Newton two months later during April 28-29, 2003. The XMM-Newton Xray image of Jupiter shows evidence of limb darkening on the anti-sunward side as seen from Earth, as well as an asymmetry with respect to the subsolar point: suggesting a solar driven process.

  10. First measurements with DUO/ROSITA pnCCDs

    Science.gov (United States)

    Meidinger, N.; Andritschke, R.; Dennerl, K.; Hälker, O.; Hasinger, G.; Hartmann, Robert; Hartner, G.; Herrmann, S.; Holl, P.; Kimmel, N.; Soltau, H.; Strüder, L.

    2005-08-01

    A new generation of pnCCDs has been developed for the proposed X-ray astronomy missions, DUO and ROSITA. The DUO/ROSITA CCD is a frame store pnCCD based on the concept of the XMM-Newton pnCCD and has both, improved performance and new features. This detector permits accurate spectroscopy of X-rays as well as imaging and high time resolution with high quantum efficiency in the energy band from 0.3 keV to 10 keV. Interfering electron-hole pair generation due to optical and UV light is prevented by a deposition of an on-chip filter. We describe the frame store pnCCDs developed and fabricated for the DUO and ROSITA missions in the semiconductor laboratory of the Max-Planck-Institut fuer extraterrestrische Physik. An overview about the CCD concept and design is given along with some details about the fabrication of the devices. In addition, we introduce a new analog signal processor which has been developed specifically for the readout of the frame store pnCCD signals. The main focus of this paper is to present the very first measurements with this CCD type and its analog signal processor. Towards this aim we report the operation of this new sensor and its key performance parameters. Finally we discuss ongoing and future tests with the DUO/ROSITA CCDs.

  11. Ten Years of Chandra

    Science.gov (United States)

    Weisskopf, Martin C.

    2009-01-01

    We celebrated the 10-th anniversary of the Launch of the Chandra X-ray Observatory on July 13, 2009. During these 10 years data from this Great Observatory have had a profound impact on 21st century astrophysics. With its unrivaled capability to produce sub-arcsecond images, the Observatory has enabled astronomers to make new discoveries in topics as diverse as comets and cosmology. We shall review some of the highlights, discuss the current status, and future plans.

  12. Chandra Images the Seething Cauldron of Starburst Galaxy

    Science.gov (United States)

    2000-01-01

    NASA's Chandra X-ray Observatory has imaged the core of the nearest starburst galaxy, Messier 82 (M82). The observatory has revealed a seething cauldron of exploding stars, neutron stars, black holes, 100 million degree gas, and a powerful galactic wind. The discovery will be presented by a team of scientists from Carnegie Mellon University, Pittsburgh, Penn., Pennsylvania State University, University Park, and the University of Michigan, Ann Arbor, on January 14 at the 195th national meeting of the American Astronomical Society. "In the disk of our Milky Way Galaxy, stars form and die in a relatively calm fashion like burning embers in a campfire," said Richard Griffiths, Professor of Astrophysics at Carnegie Mellon University. "But in a starburst galaxy, star birth and death are more like explosions in a fireworks factory." Short-lived massive stars in a starburst galaxy produce supernova explosions, which heat the interstellar gas to millions of degrees, and leave behind neutron stars and black holes. These explosions emit light in the X rays rather than in visible light. Because the superhot components inside starburst galaxies are complex and sometimes confusing, astronomers need an X-ray-detecting telescope with the highest focusing power (spatial resolution) to clearly discriminate the various structures. "NASA's Chandra X-ray Observatory is the perfect tool for studying starburst galaxies since it has the critical combination of high-resolution optics and good sensitivity to penetrating X rays," said Gordon Garmire, the Evan Pugh Professor of Astronomy and Astrophysics at Pennsylvania State University, and head of the team that conceived and built Chandra's Advanced CCD Imaging Spectrograph (ACIS) X-ray camera, which acquired the data. Many intricate structures missed by earlier satellite observatories are now visible in the ACIS image, including more than twenty powerful X-ray binary systems that contain a normal star in a close orbit around a neutron star

  13. Chandra Associates Pulsar and Historic Supernova

    Science.gov (United States)

    2001-01-01

    . Its rough cigar-like shape is in contrast to the graceful arcs observed around the Crab and Vela pulsars. However, together with those pulsars, G11.2-0.3 demonstrates that such complicated structures are ubiquitous around young pulsars. This has left astronomers confounded. Chandra observed G11.2-0.3 with the Advanced CCD Imaging Spectrometer at two epochs: August 6, 2000, and October 15, 2000, for approximately 20,000 and 15,000 seconds respectively. The ACIS X-ray camera was developed for NASA by Pennsylvania State University and MIT. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, California, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. In addition to their appointments at McGill, Dr. Kaspi is also affiliated with the Massachusetts Institute of Technology and Dr. Roberts is a Quebec Merit Postdoctoral Fellow. Funding for this work was provided by NASA, NSF, and NSERC (Canada). During the AAS meeting, the scientists involved in this release can be reached at the AAS Press Room at the Town & Country Resort in San Diego, CA. The phone numbers for the Press Room are (619) 908-5057, (619) 908-5040, and (619) 908-5041 from January 8-11. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov

  14. Lunar Prospecting With Chandra

    Science.gov (United States)

    2003-09-01

    Observations of the bright side of the Moon with NASA's Chandra X-ray Observatory have detected oxygen, magnesium, aluminum and silicon over a large area of the lunar surface. The abundance and distribution of those elements will help to determine how the Moon was formed. "We see X-rays from these elements directly, independent of assumptions about the mineralogy and other complications," said Jeremy Drake of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., at a press conference at the "Four Years with Chandra" symposium in Huntsville, Alabama. "We have Moon samples from the six widely-space Apollo landing sites, but remote sensing with Chandra can cover a much wider area," continued Drake. "It's the next best thing to being there, and it's very fast and cost-effective." The lunar X-rays are caused by fluorescence, a process similar to the way that light is produced in fluorescent lamps. Solar X-rays bombard the surface of the Moon, knock electrons out of the inner parts of the atoms, putting them in a highly unstable state. Almost immediately, other electrons rush to fill the gaps, and in the process convert their energy into the fluorescent X-rays seen by Chandra. According to the currently popular "giant impact" theory for the formation of the Moon, a body about the size of Mars collided with the Earth about 4.5 billion years ago. This impact flung molten debris from the mantle of both the Earth and the impactor into orbit around the Earth. Over the course of tens of millions of years, the debris stuck together to form the Moon. By measuring the amounts of aluminum and other elements over a wide area of the Moon and comparing them to the Earth's mantle, Drake and his colleagues plan to help test the giant impact hypothesis. "One early result," quipped Drake, "is that there is no evidence for large amounts of calcium, so cheese is not a major constituent of the Moon." Illustration of Earth's Geocorona Illustration of Earth's Geocorona The same

  15. Chandra Discovers Cosmic Cannonball

    Science.gov (United States)

    2007-11-01

    One of the fastest moving stars ever seen has been discovered with NASA's Chandra X-ray Observatory. This cosmic cannonball is challenging theories to explain its blistering speed. Astronomers used Chandra to observe a neutron star, known as RX J0822-4300, over a period of about five years. During that span, three Chandra observations clearly show the neutron star moving away from the center of the Puppis A supernova remnant. This remnant is the stellar debris field created during the same explosion in which the neutron star was created about 3700 years ago. Chandra X-ray Image of RX J0822-4300 in Puppis A Chandra X-ray Image of RX J0822-4300 in Puppis A By combining how far it has moved across the sky with its distance from Earth, astronomers determined the neutron star is moving at over 3 million miles per hour. At this rate, RX J0822-4300 is destined to escape from the Milky Way after millions of years, even though it has only traveled about 20 light years so far. "This star is moving at 3 million miles an hour, but it's so far away that the apparent motion we see in five years is less than the height of the numerals in the date on a penny, seen from the length of a football field," said Frank Winkler of Middlebury College in Vermont. "It's remarkable, and a real testament to the power of Chandra, that such a tiny motion can be measured." Labeled Image of RX J0822-4300 in Puppis A Labeled Image of RX J0822-4300 in Puppis A "Just after it was born, this neutron star got a one-way ticket out of the Galaxy," said co-author Robert Petre of NASA's Goddard Space Flight Center in Greenbelt, Md. "Astronomers have seen other stars being flung out of the Milky Way, but few as fast as this." So-called hypervelocity stars have been previously discovered shooting out of the Milky Way with speeds around one million miles per hour. One key difference between RX J0822-4300 and these other reported galactic escapees is the source of their speed. The hypervelocity stars are

  16. Towards the limit of frame transfer CCDs in beam instrumentation

    CERN Document Server

    Colchester, R J; Valentin, P

    1997-01-01

    CCDs are used for beam position and beam size measurements with screens and synchrotron radiation monitors. They have a large spatial resolution and a high dynamic range which make them interesting for high resolution two-dimensional measurements. In most applications, the video signal is digitised with a frame grabber and the beam parameters then computed. The results are limited in resolution, usually to 8 bits, and in rate. These restraints were seen as major limitations for fast and precise beam observations with synchrotron light monitors in LEP, where the revolution frequency is 11 kHz. They have been overcome by using the characteristics of Frame Transfer CCDs. Advantage is taken of the separate Image and Memory areas on the CCD chip to control independently the integration and digitising periods to achieve a 12 bit amplitude resolution at the individual pixel level. Using the CCD as a buffer memory, together with a pulsed intensifier, it is possible to make 9 to 18 two dimensional beam spot acquisitio...

  17. THE CHANDRA SOURCE CATALOG

    International Nuclear Information System (INIS)

    Evans, Ian N.; Primini, Francis A.; Glotfelty, Kenny J.; Anderson, Craig S.; Bonaventura, Nina R.; Chen, Judy C.; Doe, Stephen M.; Evans, Janet D.; Fabbiano, Giuseppina; Galle, Elizabeth C.; Gibbs, Danny G.; Grier, John D.; Hain, Roger M.; Harbo, Peter N.; He Xiangqun; Karovska, Margarita; Kashyap, Vinay L.; Davis, John E.; Houck, John C.; Hall, Diane M.

    2010-01-01

    The Chandra Source Catalog (CSC) is a general purpose virtual X-ray astrophysics facility that provides access to a carefully selected set of generally useful quantities for individual X-ray sources, and is designed to satisfy the needs of a broad-based group of scientists, including those who may be less familiar with astronomical data analysis in the X-ray regime. The first release of the CSC includes information about 94,676 distinct X-ray sources detected in a subset of public Advanced CCD Imaging Spectrometer imaging observations from roughly the first eight years of the Chandra mission. This release of the catalog includes point and compact sources with observed spatial extents ∼<30''. The catalog (1) provides access to the best estimates of the X-ray source properties for detected sources, with good scientific fidelity, and directly supports scientific analysis using the individual source data; (2) facilitates analysis of a wide range of statistical properties for classes of X-ray sources; and (3) provides efficient access to calibrated observational data and ancillary data products for individual X-ray sources, so that users can perform detailed further analysis using existing tools. The catalog includes real X-ray sources detected with flux estimates that are at least 3 times their estimated 1σ uncertainties in at least one energy band, while maintaining the number of spurious sources at a level of ∼<1 false source per field for a 100 ks observation. For each detected source, the CSC provides commonly tabulated quantities, including source position, extent, multi-band fluxes, hardness ratios, and variability statistics, derived from the observations in which the source is detected. In addition to these traditional catalog elements, for each X-ray source the CSC includes an extensive set of file-based data products that can be manipulated interactively, including source images, event lists, light curves, and spectra from each observation in which a

  18. A Chandra Observation of the Recurrent Supersoft X-ray Transient in NGC 300

    Science.gov (United States)

    Kong, A. K. H.; di Stefano, R.

    2008-07-01

    We report a Chandra observation of the supersoft X-ray transient (XMMU J005510.7-373855) recently in outburst in NGC 300 (Kong & Di Stefano 200; ATel #1560). A 10ks DDT observation was taken on 2008 July 8 UT with ACIS-S in Very Faint mode. The supersoft X-ray transient was clearly detected with all photons from below 0.7 keV. The energy spectrum is well fitted with an absorbed blackbody model with N_H=(4.3+/-1)e20 cm^-2 and kT=61+/-6 eV (90% confidence).

  19. The Chandra Source Catalog 2.0: Spectral Properties

    Science.gov (United States)

    McCollough, Michael L.; Siemiginowska, Aneta; Burke, Douglas; Nowak, Michael A.; Primini, Francis Anthony; Laurino, Omar; Nguyen, Dan T.; Allen, Christopher E.; Anderson, Craig S.; Budynkiewicz, Jamie A.; Chen, Judy C.; Civano, Francesca Maria; D'Abrusco, Raffaele; Doe, Stephen M.; Evans, Ian N.; Evans, Janet D.; Fabbiano, Giuseppina; Gibbs, Danny G., II; Glotfelty, Kenny J.; Graessle, Dale E.; Grier, John D.; Hain, Roger; Hall, Diane M.; Harbo, Peter N.; Houck, John C.; Lauer, Jennifer L.; Lee, Nicholas P.; Martínez-Galarza, Juan Rafael; McDowell, Jonathan C.; Miller, Joseph; McLaughlin, Warren; Morgan, Douglas L.; Mossman, Amy E.; Nichols, Joy S.; Paxson, Charles; Plummer, David A.; Rots, Arnold H.; Sundheim, Beth A.; Tibbetts, Michael; Van Stone, David W.; Zografou, Panagoula; Chandra Source Catalog Team

    2018-01-01

    The second release of the Chandra Source Catalog (CSC) contains all sources identified from sixteen years' worth of publicly accessible observations. The vast majority of these sources have been observed with the ACIS detector and have spectral information in 0.5-7 keV energy range. Here we describe the methods used to automatically derive spectral properties for each source detected by the standard processing pipeline and included in the final CSC. The sources with high signal to noise ratio (exceeding 150 net counts) were fit in Sherpa (the modeling and fitting application from the Chandra Interactive Analysis of Observations package) using wstat as a fit statistic and Bayesian draws method to determine errors. Three models were fit to each source: an absorbed power-law, blackbody, and Bremsstrahlung emission. The fitted parameter values for the power-law, blackbody, and Bremsstrahlung models were included in the catalog with the calculated flux for each model. The CSC also provides the source energy fluxes computed from the normalizations of predefined absorbed power-law, black-body, Bremsstrahlung, and APEC models needed to match the observed net X-ray counts. For sources that have been observed multiple times we performed a Bayesian Blocks analysis will have been performed (see the Primini et al. poster) and the most significant block will have a joint fit performed for the mentioned spectral models. In addition, we provide access to data products for each source: a file with source spectrum, the background spectrum, and the spectral response of the detector. Hardness ratios were calculated for each source between pairs of energy bands (soft, medium and hard). This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  20. Dark Matter Reality Check: Chandra Casts Cloud On Alternative Theory

    Science.gov (United States)

    2002-10-01

    has successfully distinguished dark matter from MOND. The researchers also found that the Chandra data fit predictions of the cold dark matter theories, according to which dark matter consists of slowly moving particles, which interact with each other and "normal" matter only through gravity. Other forms of dark matter, such as self-interacting dark matter, and cold molecular dark matter, are not consistent with the observation in that they require a dark matter halo that is too round or too flat, respectively. "Chandra's ability to precisely identify and locate the point-like sources contaminating the diffuse emission in the X-ray image was absolutely essential," said Buote. "Only then could we make accurate measurements of the shape and orientation of the X-ray image contours." The conclusion from the Chandra data that NGC 720 possesses a dark matter halo assumes that the hot gas cloud has not been unduly disturbed by collisions or mergers with other galaxies in the last 100 million years. The lack of evidence of such activity indicates that this assumption is valid. Chandra observed NGC 720, which is about 80 million light years from Earth, for 11 hours with the Advanced CCD Imaging Spectrometer (ACIS). Other members of the team include Tesla Jeltema and Claude Canizares of Massachusetts Institute of Technology (MIT) in Cambridge, and Gordon Garmire of Pennsylvania State University in University Park. Penn State and MIT developed the instrument for NASA. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program, and TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass.

  1. The End of Days -- Chandra Catches X-ray Glow From Supernova

    Science.gov (United States)

    1999-12-01

    operations team replanned the telescope's observation activities and by Monday morning, and by Monday morning, Chandra was pointed at the supernova and observed it for about nine hours. Lewin, who had been awarded the rights to Chandra's first observation of a nearby supernova, was ecstatic. "This is a unique chance that we have been hoping for!!!!" he wrote in an e-mail to Tananbaum. "I was impressed by how rapid the Chandra response was, " said Kirshner. "Supernovae expand quickly and cool quickly, so each day we delay observing the supernova it has changed irretrievably," Filippenko said. "We caught this really early, only a day or two after the explosion. We were lucky." The Chandra observation was taken with the Advanced CCD Imaging Spectrometer (ACIS) on November 1 and 2, and 11 and 12, 1999 in two separate observations that lasted approximately nine hours each. ACIS was built by Pennsylvania State University, University Park. and MIT. To follow Chandra's progress, visit the Chandra site at: http://chandra.harvard.edu AND http://chandra.nasa.gov NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. This image will be available on NASA Video File which airs at noon, 3:00 p.m., 6:00 p.m., 9:00 p.m. and midnight Eastern Time. NASA Television is available on GE-2, transponder 9C at 85 degrees West longitude, with vertical polarization. Frequency is on 3880.0 megahertz, with audio on 6.8 megahertz. High resolution digital versions of the X-ray image (JPG, 300 dpi TIFF ) and other information associated with this release are available on the Internet at: http://chandra.harvard.edu/photo/sn1999em/ or via links in: http://chandra.harvard.edu

  2. Cooled CCDs for recording data from electron microscopes

    CERN Document Server

    Faruqi, A R

    2000-01-01

    A cooled-CCD camera based on a low-noise scientific grade device is described in this paper used for recording images in a 120 kV electron microscope. The primary use of the camera is for recording electron diffraction patterns from two-dimensionally ordered arrays of proteins at liquid-nitrogen temperatures leading to structure determination at atomic or near-atomic resolution. The traditional method for recording data in the microscope is with electron sensitive film but electronic detection methods offer the following advantages over film methods: the data is immediately available in a digital format which can be displayed on a monitor screen for visual inspection whereas a film record needs to be developed and digitised, a lengthy process taking at least several hours, prior to inspection; the dynamic range of CCD detectors is about two orders of magnitude greater with better linearity. The accuracy of measurements is also higher for CCDs, particularly for weak signals due to inherent fog levels in film. ...

  3. Archon: A modern controller for high performance astronomical CCDs

    Science.gov (United States)

    Bredthauer, Greg

    2014-08-01

    The rapid evolution of commercial FPGAs and analog ICs has enabled the development of Archon, a new modular high performance astronomical CCD controller. CCD outputs are digitized by 16-bit 100 MHz ADCs with differential AC-coupled preamplifiers. The raw data stream from an ADC can be stored in parallel with standard image data into three onboard 512 MB frame buffers. Pixel values are computed using digital correlated double sampling. At low pixel rates (power up and down in a customizable sequence. Communication between the controller and a host computer occurs over a gigabit Ethernet interface (fiber or copper). A CCD configuration is specified by a simple text file. Together, these features simplify the tuning and debugging of scientific CCDs, and enable CCD-limited imaging. I present details of the controller architecture, examples of CCD tuning, and measured performance data of the controller alone (dynamic range of 108 dB at 100 kHz and 98 dB at 1 MHz) and in combination with an STA1600LN CCD.

  4. Patel, Prof. Chandra Kumar Naranbhai

    Indian Academy of Sciences (India)

    Patel, Prof. Chandra Kumar Naranbhai. Date of birth: 2 July 1938. Address: President & CEO, Pranalytica Inc., 1101, Colorado Avenue, Santa Monica, CA 90401, U.S.A.. Contact: Office: (+1-310) 458 0808. Residence: (+1-310) 471 6505. Fax: (+1-310) 458 0171. Email: patel@pranalytica.com. YouTube · Twitter · Facebook ...

  5. Chandra Madramootoo | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... Technology (MIT). He previously served as Dean of the Faculty of Agricultural and Environmental Sciences and as Director of the Brace Centre for Water Resources Management at McGill University. Currently, Chandra is Chair of the Board of Trustees of the International Crops Research Institute for the Semi-Arid Tropics.

  6. The Chandra Galactic Bulge Survey

    NARCIS (Netherlands)

    Hynes, Robert I.; Jonker, P.G.; Bassa, C. G.; Dieball, A.; Greiss, S.; Maccarone, T. J.; Nelemans, G.; Steeghs, D.; Torres, M. A. P.; Britt, C. T.; Clem, J. L.; Gossen, L.; Grindlay, J. E.; Groot, P.J.; Kuiper, L.; Kuulkers, E.; Mendez, M.; Mikles, V. J.; Ratti, E. M.; Rea, N.; van Haaften, L.; Wijnands, R.; in't Zand, J. J. M.

    The Chandra Galactic Bulge Survey (CGBS) is a shallow but wide survey of two approximately 6x1 degree strips of the Galactic Bulge about a degree above and below the plane. The survey by design targets regions where extinction and crowding are manageable and optical counterparts are accessible to

  7. The Chandra Galactic Bulge Survey

    NARCIS (Netherlands)

    Hynes, Robert I.; Jonker, P. G.; Bassa, C. G.; Nelemans, G.; Steeghs, D.; Torres, M. A. P.; Maccarone, T. J.; Greiss, S.; Clem, J.; Dieball, A.; Mikles, V. J.; Britt, C. T.; Gossen, L.; Collazzi, A. C.; Wijnands, R.; In't Zand, J. J. M.; Mendez, M.; Rea, N.; Kuulkers, E.; Ratti, E. M.; van Haaften, L. M.; Heinke, C.; Ozel, F.; Groot, P. J.; Verbunt, F.

    2012-01-01

    The Chandra Galactic Bulge Survey (GBS) is a shallow but wide survey of two approximately 6x1 degree strips of the Galactic Bulge about a degree above and below the plane. The survey by design targets regions where extinction and crowding are manageable and optical counterparts are accessible to

  8. The Chandra Galactic Bulge Survey

    NARCIS (Netherlands)

    Hynes, Robert I.; Jonker, P. G.; Bassa, C. G.; Nelemans, G.; Steeghs, D.; Torres, M. A. P.; Maccarone, T. J.; Greiss, S.; Clem, J.; Dieball, A.; Mikles, V. J.; Britt, C. T.; Gossen, L.; Collazzi, A. C.; Wijnands, R.; In't Zand, J. J. M.; Mendez, M.; Rea, N.; Kuulkers, E.; Ratti, E. M.; van Haaften, L. M.; Heinke, C.; Ozel, F.; Groot, P. J.; Verbunt, F.

    The Chandra Galactic Bulge Survey (GBS) is a shallow but wide survey of two approximately 6x1 degree strips of the Galactic Bulge about a degree above and below the plane. The survey by design targets regions where extinction and crowding are manageable and optical counterparts are accessible to

  9. Prafulla Chandra Rây

    Indian Academy of Sciences (India)

    The decade of 1860-69 alone saw the birth of Rabindranath Tagore, Motilal Nehru, Swami Vivekananda, ... Prafulla Chandra studied it in Presidency College since his own college, Metropolitan Institution (now Vidyasagar College), did not have the facilities. The chemistry lectures of Alexander Pedler fascinated him - 'I ...

  10. Dutta Roy, Prof. Suhash Chandra

    Indian Academy of Sciences (India)

    Suhash Chandra D.Phil. (Calcutta), FNA, FNAE, FNASc. Date of birth: 1 November 1937. Specialization: Signal Processing, Network Theory and Electronic Circuits Address: 164, SFS Apartments, Hauz Khas, New Delhi 110 016, U.T.. Contact: Residence: (011) 2696 3054. Mobile: 98714 70136. Email: scdroy@ee.iitd.ac.in.

  11. A Chandra observation of the neutron-star transient IGR J18245-2452 in M28

    Science.gov (United States)

    Homan, Jeroen; Pooley, David

    2013-05-01

    We observed the globular cluster M28 with Chandra/ACIS-S to identify the recently discovered neutron-star X-ray transient IGR J18245-2452 (ATel #4925, #4927). The 14.8 ks observation started on 2013 April 28 at 19:37 UT. The high-energy transmission gratings were inserted to avoid possible pile-up effects. An inspection of the resulting image reveals only one X-ray source in the 0.5 ATCA error circle (ATel #4981), source 23 from Becker et al.

  12. VizieR Online Data Catalog: 6Ms Chandra long-term analyses of AGNs (Yang+, 2016)

    Science.gov (United States)

    Yang, G.; Brandt, W. N.; Luo, B.; Xue, Y. Q.; Bauer, F. E.; Sun, M. Y.; Kim, S.; Schulze, S.; Zheng, X. C.; Paolillo, M.; Shemmer, O.; Liu, T.; Schneider, D. P.; Vignali, C.; Vito, F.; Wang, J.-X.

    2017-02-01

    This work is based on the Chandra CDF-S data. The observations were taken from 1999 October to 2015 January with a total observation time of 5.7Ms. In total, there are 84 observations utilized with median exposure time ~60ks. All of the 84 observations were performed using the Advanced CCD Imaging Spectrometer imaging array (ACIS-I). See B. Luo et al. 2016, in prep (L16) for more observation details. Sixty-eight sources are selected with 649-11283 counts; the median number of counts is 1399. (1 data file).

  13. Selective HDAC inhibition by ACY-241 enhances the activity of paclitaxel in solid tumor models.

    Science.gov (United States)

    Huang, Pengyu; Almeciga-Pinto, Ingrid; Jarpe, Matthew; van Duzer, John H; Mazitschek, Ralph; Yang, Min; Jones, Simon S; Quayle, Steven N

    2017-01-10

    ACY-241 is a novel, orally available and selective histone deacetylase (HDAC) 6 inhibitor in Phase 1b clinical development in multiple myeloma (NCT 02400242). Like the structurally related drug ACY-1215 (ricolinostat), ACY-241 has the potential for a substantially reduced side effect profile versus current nonselective HDAC inhibitor drug candidates due to reduced potency against Class I HDACs while retaining the potential for anticancer effectiveness. We now show that combination treatment of xenograft models with paclitaxel and either ricolinostat or ACY-241 significantly suppresses solid tumor growth. In cell lines from multiple solid tumor lineages, combination treatment with ACY-241 and paclitaxel enhanced inhibition of proliferation and increased cell death relative to either single agent alone. Combination treatment with ACY-241 and paclitaxel also resulted in more frequent occurrence of mitotic cells with abnormal multipolar spindles and aberrant mitoses, consistent with the observed increase of aneuploid cells. At the molecular level, multipolar mitotic spindle formation was observed to be NuMA-dependent and γ-tubulin independent, suggesting that treatment-induced multipolar spindle formation does not depend on centrosomal amplification. The significantly enhanced efficacy of ACY-241 plus paclitaxel observed here, in addition to the anticipated superior safety profile of a selective HDAC6 inhibitor versus pan-HDAC inhibitors, provides a strong rationale for clinical development of this combination in patients with advanced solid tumors.

  14. Chandra Early Type Galaxy Atals

    Science.gov (United States)

    Kim, Dong-Woo; Anderson, Craig; Burke, Douglas J.; Fabbiano, Giuseppina; Fruscione, Antonella; Lauer, Jennifer; McCollough, Michael; Morgan, Douglas; Mossman, Amy; O'Sullivan, Ewan; Paggi, Alessandro; Vrtilek, Saeqa Dil; Trinchieri, Ginevra

    2017-08-01

    The hot gas in early type galaxies (ETGs) plays a crucial role in understanding their formation and evolution. As the hot gas is often extended to the outskirts beyond the optical size, the large scale structural features identified by Chandra (including jets, cavities, cold fronts, filaments and tails) point to key evolutionary mechanisms, e.g., AGN feedback, merging history, accretion, stripping and star formation and its quenching. We have systematically analyzed the archival Chandra data of ~100 ETGs to study the hot ISM. We produce the uniformly derived data products with spatially resolved spectral information and will make them accessible via a public web site. With 2D spectral infomation, we further discuss gas morphology, scaling relations, X-ray based mass profiles and their implications related to various physical mechanisms (e.g., stellar and AGN feedback).

  15. Closed and Not Closed: Mitigating a Mystery on Chandra's Door

    Science.gov (United States)

    Odom, Brian

    2015-01-01

    The Chandra X-ray Observatory is part of NASA's fleet of "Great Observatories" along with the Hubble Space Telescope, the Spitzer Space Telescope, and the now deorbited Compton Gamma Ray Observatory. The observatory was designed to detect x-ray emissions from some of the hottest regions of the galaxy including exploded stars, clusters of galaxies, and matter around black holes. One of the observatory's key scientific instruments is the Advanced CCD Imaging Spectrometer (ACIS), which is one of four primary and two focal plane instruments. Due to the sensitivity of the charged coupled devices (CCD's), an aperture door was designed and built by Lockheed-Martin that protected the instrument during testing and the time leading up to launch. The design called for a system of wax actuators (manufactured by STARSYS Corp) to be used as components in a rotary actuator that would open and close the door during ground testing and on-orbit operations. Another feature of the design was an internal shear disc located in each actuator to prevent excessive internal pressure and to shield other components from damage.

  16. Chandra Catches "Piranha" Black Holes

    Science.gov (United States)

    2007-07-01

    Supermassive black holes have been discovered to grow more rapidly in young galaxy clusters, according to new results from NASA's Chandra X-ray Observatory. These "fast-track" supermassive black holes can have a big influence on the galaxies and clusters that they live in. Using Chandra, scientists surveyed a sample of clusters and counted the fraction of galaxies with rapidly growing supermassive black holes, known as active galactic nuclei (or AGN). The data show, for the first time, that younger, more distant galaxy clusters contained far more AGN than older, nearby ones. Galaxy clusters are some of the largest structures in the Universe, consisting of many individual galaxies, a few of which contain AGN. Earlier in the history of the universe, these galaxies contained a lot more gas for star formation and black hole growth than galaxies in clusters do today. This fuel allows the young cluster black holes to grow much more rapidly than their counterparts in nearby clusters. Illustration of Active Galactic Nucleus Illustration of Active Galactic Nucleus "The black holes in these early clusters are like piranha in a very well-fed aquarium," said Jason Eastman of Ohio State University (OSU) and first author of this study. "It's not that they beat out each other for food, rather there was so much that all of the piranha were able to really thrive and grow quickly." The team used Chandra to determine the fraction of AGN in four different galaxy clusters at large distances, when the Universe was about 58% of its current age. Then they compared this value to the fraction found in more nearby clusters, those about 82% of the Universe's current age. The result was the more distant clusters contained about 20 times more AGN than the less distant sample. AGN outside clusters are also more common when the Universe is younger, but only by factors of two or three over the same age span. "It's been predicted that there would be fast-track black holes in clusters, but we never

  17. Measurement of lateral charge diffusion in thick, fully depleted, back-illuminated CCDs

    Energy Technology Data Exchange (ETDEWEB)

    Karcher, Armin; Bebek, Christopher J.; Kolbe, William F.; Maurath, Dominic; Prasad, Valmiki; Uslenghi, Michela; Wagner, Martin

    2004-06-30

    Lateral charge diffusion in back-illuminated CCDs directly affects the point spread function (PSF) and spatial resolution of an imaging device. This can be of particular concern in thick, back-illuminated CCDs. We describe a technique of measuring this diffusion and present PSF measurements for an 800 x 1100, 15 mu m pixel, 280 mu m thick, back-illuminated, p-channel CCD that can be over-depleted. The PSF is measured over a wavelength range of 450 nm to 650 nm and at substrate bias voltages between 6 V and 80 V.

  18. Chandra Evidence of a Flattened, Triaxial Dark Matter Halo in the Elliptical Galaxy NGC 720

    Science.gov (United States)

    Buote, David A.; Jeltema, Tesla E.; Canizares, Claude R.; Garmire, Gordon P.

    2002-09-01

    We present an analysis of a Chandra ACIS-S observation of the elliptical galaxy NGC 720, to verify the existence of a dark matter halo and to measure its ellipticity. The ACIS-S3 image reveals over 60 point sources distributed throughout the field, most of which were undetected and therefore unaccounted for in previous X-ray studies. For semimajor axes a~150'' out to a=185'' (22.4h-170 kpc), which is near the edge of the S3 CCD, ɛX and P.A. diverge from their values at smaller a. Possible origins of this behavior at the largest a are discussed. Overall, the ellipticities and P.A. twist for aRomanowsky & Kochanek (which could not produce the abrupt P.A. twist in the ROSAT HRI data). Since the optical image displays no substantial isophote twisting, the X-ray P.A. twist requires a massive dark matter halo if the hot gas is in hydrostatic equilibrium. Furthermore, the values of ɛX obtained by Chandra are too large to be explained if the gravitating mass follows the optical light (M~L*), irrespective of the P.A. twist. The M~L* hypothesis is inconsistent with the Chandra ellipticities at the 96% confidence level, assuming oblate symmetry, and at the 98% confidence level for prolate symmetry. Thus, both the P.A. twist and the ellipticities of the Chandra image imply the existence of dark matter, independent of the temperature profile of the gas. This geometric evidence for dark matter cannot be explained by alternative gravity theories, such as the modification of Newtonian dynamics (MOND). To constrain the ellipticity of the dark matter halo, we considered both oblate and prolate spheroidal mass models to bracket the full range of (projected) ellipticities of a triaxial ellipsoid. The dark matter density model, ρ~(a2s+a2)-1, provides the best fit to the data and gives ellipticities and 1 σ errors of ɛ=0.37+/-0.03 for oblate and ɛ=0.36+/-0.02 for prolate models. Navarro-Frenk-White (NFW) and Hernquist models give similar ellipticities for the dark matter. These

  19. Chandra Source Catalog: User Interface

    Science.gov (United States)

    Bonaventura, Nina; Evans, Ian N.; Rots, Arnold H.; Tibbetts, Michael S.; van Stone, David W.; Zografou, Panagoula; Primini, Francis A.; Glotfelty, Kenny J.; Anderson, Craig S.; Chen, Judy C.; Davis, John E.; Doe, Stephen M.; Evans, Janet D.; Fabbiano, Giuseppina; Galle, Elizabeth C.; Gibbs, Danny G., II; Grier, John D.; Hain, Roger; Hall, Diane M.; Harbo, Peter N.; He, Helen; Houck, John C.; Karovska, Margarita; Kashyap, Vinay L.; Lauer, Jennifer; McCollough, Michael L.; McDowell, Jonathan C.; Miller, Joseph B.; Mitschang, Arik W.; Morgan, Douglas L.; Mossman, Amy E.; Nichols, Joy S.; Nowak, Michael A.; Plummer, David A.; Refsdal, Brian L.; Siemiginowska, Aneta L.; Sundheim, Beth A.; Winkelman, Sherry L.

    2009-09-01

    The Chandra Source Catalog (CSC) is intended to be the definitive catalog of all X-ray sources detected by Chandra. For each source, the CSC provides positions and multi-band fluxes, as well as derived spatial, spectral, and temporal source properties. Full-field and source region data products are also available, including images, photon event lists, light curves, and spectra. The Chandra X-ray Center CSC website (http://cxc.harvard.edu/csc/) is the place to visit for high-level descriptions of each source property and data product included in the catalog, along with other useful information, such as step-by-step catalog tutorials, answers to FAQs, and a thorough summary of the catalog statistical characterization. Eight categories of detailed catalog documents may be accessed from the navigation bar on most of the 50+ CSC pages; these categories are: About the Catalog, Creating the Catalog, Using the Catalog, Catalog Columns, Column Descriptions, Documents, Conferences, and Useful Links. There are also prominent links to CSCview, the CSC data access GUI, and related help documentation, as well as a tutorial for using the new CSC/Google Earth interface. Catalog source properties are presented in seven scientific categories, within two table views: the Master Source and Source Observations tables. Each X-ray source has one ``master source'' entry and one or more ``source observation'' entries, the details of which are documented on the CSC ``Catalog Columns'' pages. The master source properties represent the best estimates of the properties of a source; these are extensively described on the following pages of the website: Position and Position Errors, Source Flags, Source Extent and Errors, Source Fluxes, Source Significance, Spectral Properties, and Source Variability. The eight tutorials (``threads'') available on the website serve as a collective guide for accessing, understanding, and manipulating the source properties and data products provided by the catalog.

  20. Chandra Observations of M31 and their Implications for its ISM

    Science.gov (United States)

    Primini, F.; Garcia, M.; Murray, S.; Forman, W.; Jones, C.; McClintock, J.

    2000-01-01

    As part of the Chandra X-ray Observatory's Survey/Monitoring Program of M31, we have been regularly observing the bulge amd inner disk of M31 for nearly 1 year, using both the HRC and ACIS Instruments. We present results from our program th it are of interest to the study of the ISM in M31. In particular, spectral analysis of bright, unresolved x-ray sources in the bulge reveals the presence of significant local x-ray extinction (N(sub H) is about 2 x 10(exp 21)/square cm), and we will attempt to map out this extinction, Further, we find that diffuse emission accounts for a significant fraction of the overall x-ray flux from the bulge. Finally, our search for x-ray counterparts to supernova remnants in M31 yields surprisingly few candidates.

  1. VizieR Online Data Catalog: Collinder 261 Chandra sources & optical counterparts (Vats+, 2017)

    Science.gov (United States)

    Vats, S.; van den Berg, M.

    2017-10-01

    Cr 261 was observed with the Advanced CCD Imaging Spectrometer (ACIS) on board Chandra starting 2009 November 9 14:50 UTC, for a total exposure time of 53.8ks (ObsID 11308). We retrieved optical images of Cr 261 in the B and V bands from the ESO public archive. These data were taken as part of the ESO Imaging Survey (EIS; program ID 164.O-0561). The observations of Cr 261 were made using the Wide Field Imager (WFI), mounted on the 2.2m MPG/ESO telescope at La Silla, Chile. The Cr 261 data were taken from 2001 June 27 23:55 UTC to 2001 June 28 00:38 UTC, with a total exposure time of 510s in the B and V filter each. (2 data files).

  2. From electrons to stars : modelling and mitigation of radiation damage effects on astronomical CCDs

    NARCIS (Netherlands)

    Prod'homme, Thibaut

    2011-01-01

    The work presented in this thesis is part of an on-going effort to understand and mitigate the effects of radiation damage in astronomical CCDs. My research was motivated by and took place in the challenging context of the European Space Agency’s (ESA) astrometric mission, Gaia, for which radiation

  3. First Results from a Deep Chandra Survey of the Hubble Deep Field Area

    Science.gov (United States)

    Brandt, W. N.; Hornschemeier, A. E.; Garmire, G. P.; Schneider, D. P.; Barger, A. J.; Bautz, M. W.; Burrows, D. N.; Chartas, G.; Cowie, L. L.; Feigelson, E. D.; Griffiths, R.; Lumb, D.; Nousek, J. A.; Sargent, W. L. W.; Townsley, L. K.

    2000-05-01

    We present results from a Chandra study of the Hubble Deep Field (HDF) and its environs obtained using 237 ks of data collected by the Advanced CCD Imaging Spectrometer (ACIS). This is one of the deepest X-ray observations ever reported, and we have detected at least six X-ray sources in the HDF itself. Comparing these with objects seen in multiwavelength HDF studies shows positional coincidences with the extremely red object NICMOS J123651.74+621221.4, an active galactic nucleus (AGN), three elliptical galaxies, and one nearby spiral galaxy. We also place X-ray upper limits on AGN candidates found in the HDF, and we present the tightest constraints yet on X-ray emission from the SCUBA submillimeter source population. Most of the submillimeter sources appear to be dominated by star formation or have AGN with Compton-thick tori and little circumnuclear X-ray scattering. Furthermore, we highlight optical spectroscopy results for X-ray sources detected in the full ACIS field of view, using data collected by the Hobby-Eberly and Keck Telescopes. We describe future plans to extend this research. We acknowledge the financial support of NASA grant NAS 8-38252.

  4. Tamoxifen induces regression of estradiol-induced mammary cancer in ACI.COP-Ept2 rat model

    OpenAIRE

    Ruhlen, Rachel L.; Willbrand, Dana M.; Besch-Williford, Cynthia L.; Ma, Lixin; Shull, James D.; Sauter, Edward R.

    2008-01-01

    The ACI rat is a unique model of human breast cancer in that mammary cancers are induced by estrogen without carcinogens, irradiation, xenografts or transgenic manipulations. We sought to characterize mammary cancers in a congenic variant of the ACI rat, the ACI.COP-Ept2. All rats with estradiol implants developed mammary cancers in 5–7 months. Rats bearing estradiol-induced mammary cancers were treated with tamoxifen for three weeks. Tamoxifen reduced tumor mass, measured by magnetic resonan...

  5. Chandra Studies of Nearby Radio and Seyfert Galaxies

    Science.gov (United States)

    Wilson, A. S.

    2001-09-01

    I shall describe some of the results of a Chandra ACIS program on the extended, universally bi-polar, X-ray emission of nearby radio galaxies and Seyfert galaxies, with emphasis on the diversity of the radiation mechanisms involved and the implications for our understanding of the AGN phenomenon. a) Radio galaxies. The X-ray emission from the hot spots of Cygnus A are synchrotron self-Compton emission from the synchrotron radio emitting electrons in a magnetic field which is close to equipartition (the papers by Young et al. and Smith et al. describe our Chandra results on the nucleus and cluster gas of Cygnus A, respectively). The X-ray knots of the M87 jet are almost certainly synchrotron radiation, as judged by their steep spectra. Preliminary results of a long integration on the Virgo cluster ICM will be presented. The X-ray radiation mechanism of the jet and western hot spot of Pictor A remains uncertain, with evidence favoring synchrotron radiation and bulk relativistic outflow of the jet and, remarkably, the western hot spot. b) Seyfert galaxies. For the Circinus galaxy, NGC 1068 and NGC 4151, the bulk of the X-ray emitting gas is photoionized by the nucleus. There is some evidence for thermal plasma emission powered by the starburst in Circinus and by the jet-driven outflows in NGC 1068. In M51, the bi-polar nuclear lobes previously found in radio continuum and optical line emission show up in X-rays as thermal plasma emission from shocked gas with kT ~ 0.5 keV. The nucleus is obscured by a column density in excess of 1024 cm-2 (see paper by Terashima et al.). In NGC 4258, the X-rays (which are thermal plasma emission from gas with kT ~ 0.3 - 0.6 keV) are dominated by the ``anomalous arms''. These arms represent dense gas in the galaxy disk shocked by mass motions driven into the low density halo gas (which then collides with the disk) by the out-of-disk radio jet. The extended X-ray emission powered by active galaxies thus depends on the relative

  6. Probing Large-scale Coherence between Spitzer IR and Chandra X-Ray Source-subtracted Cosmic Backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Cappelluti, N.; Urry, M. [Yale Center for Astronomy and Astrophysics, P.O. Box 208120, New Haven, CT 06520 (United States); Arendt, R. [University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Kashlinsky, A. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Li, Y.; Hasinger, G. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Helgason, K. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Natarajan, P. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Finoguenov, A. [Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, D-85741, Garching bei München (Germany)

    2017-09-20

    We present new measurements of the large-scale clustering component of the cross-power spectra of the source-subtracted Spitzer -IRAC cosmic infrared background and Chandra -ACIS cosmic X-ray background surface brightness fluctuations Our investigation uses data from the Chandra Deep Field South, Hubble Deep Field North, Extended Groth Strip/AEGIS field, and UDS/SXDF surveys, comprising 1160 Spitzer hours and ∼12 Ms of Chandra data collected over a total area of 0.3 deg{sup 2}. We report the first (>5 σ ) detection of a cross-power signal on large angular scales >20″ between [0.5–2] keV and the 3.6 and 4.5 μ m bands, at ∼5 σ and 6.3 σ significance, respectively. The correlation with harder X-ray bands is marginally significant. Comparing the new observations with existing models for the contribution of the known unmasked source population at z < 7, we find an excess of about an order of magnitude at 5 σ confidence. We discuss possible interpretations for the origin of this excess in terms of the contribution from accreting early black holes (BHs), including both direct collapse BHs and primordial BHs, as well as from scattering in the interstellar medium and intra-halo light.

  7. Probing Large-scale Coherence between Spitzer IR and Chandra X-Ray Source-subtracted Cosmic Backgrounds

    Science.gov (United States)

    Cappelluti, N.; Arendt, R.; Kashlinsky, A.; Li, Y.; Hasinger, G.; Helgason, K.; Urry, M.; Natarajan, P.; Finoguenov, A.

    2017-09-01

    We present new measurements of the large-scale clustering component of the cross-power spectra of the source-subtracted Spitzer-IRAC cosmic infrared background and Chandra-ACIS cosmic X-ray background surface brightness fluctuations Our investigation uses data from the Chandra Deep Field South, Hubble Deep Field North, Extended Groth Strip/AEGIS field, and UDS/SXDF surveys, comprising 1160 Spitzer hours and ˜12 Ms of Chandra data collected over a total area of 0.3 deg2. We report the first (>5σ) detection of a cross-power signal on large angular scales >20″ between [0.5-2] keV and the 3.6 and 4.5 μm bands, at ˜5σ and 6.3σ significance, respectively. The correlation with harder X-ray bands is marginally significant. Comparing the new observations with existing models for the contribution of the known unmasked source population at z < 7, we find an excess of about an order of magnitude at 5σ confidence. We discuss possible interpretations for the origin of this excess in terms of the contribution from accreting early black holes (BHs), including both direct collapse BHs and primordial BHs, as well as from scattering in the interstellar medium and intra-halo light.

  8. Chandra's Find of Lonely Halo Raises Questions About Dark Matter

    Science.gov (United States)

    2004-10-01

    elliptical galaxies will be required before this issue can be resolved." Chandra observed NGC 4555 with its Advanced CCD Imaging Spectrometer (ACIS) in February 2003. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for NASA's Office of Space Science, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

  9. Comparison of proton irradiated P-channel and N-channel CCDs

    Energy Technology Data Exchange (ETDEWEB)

    Gow, Jason P.D., E-mail: j.p.d.gow@open.ac.uk [e2v Centre for Electronic Imaging, Planetary and Space Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Murray, Neil J.; Holland, Andrew D. [e2v Centre for Electronic Imaging, Planetary and Space Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Burt, David; Pool, Peter J. [e2v Technologies plc, 106 Waterhouse Lance, Chelmsford, Essex CM1 2QU (United Kingdom)

    2012-09-11

    Charge transfer inefficiency and dark current effects are compared for e2v Technologies plc p-channel and n-channel CCDs, both irradiated with protons. The p-channel devices, prior to their irradiation, exhibited twice the dark current and considerable worse charge transfer inefficiency (CTI) than a typical n-channel. The radiation induced increase in dark current was found to be comparable with n-channel CCDs, and its temperature dependence suggest that the divacancy is the dominant source of thermally generated dark current pre- and post-irradiation. The factor of improvement in tolerance to radiation induced CTI varied by between 15 and 25 for serial CTI and 8 and 3 for parallel CTI, between -70 Degree-Sign C and -110 Degree-Sign C, respectively.

  10. Improved Spatial Resolution in Thick, Fully-Depleted CCDs withEnhanced Red Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Fairfield, Jessamyn A.; Groom, Donald E.; Bailey, Stephen J.; Bebek, Christopher J.; Holland, Stephen E.; Karcher, Armin; Kolbe,William F.; Lorenzon, Wolfgang; Roe, Natalie A.

    2006-03-09

    The point spread function (PSF) is an important measure of spatial resolution in CCDs for point-like objects, since it affects image quality and spectroscopic resolution. We present new data and theoretical developments for lateral charge diffusion in thick, fully-depleted charge-coupled devices (CCDs) developed at Lawrence Berkeley National Laboratory (LBNL). Because they can be over-depleted, the LBNL devices have no field-free region and diffusion is controlled through the application of an external bias voltage. We give results for a 3512 x 3512 format, 10.5 {micro}m pixel back-illuminated p-channel CCD developed for the SuperNova/Acceleration Probe (SNAP), a proposed satellite-based experiment designed to study dark energy. The PSF was measured at substrate bias voltages between 3 V and 115 V. At a bias voltage of 115 V, we measure an rms diffusion of 3.7 {+-} 0.2 {micro}m. Lateral charge diffusion in LBNL CCDs will meet the SNAP requirements.

  11. Improved Spatial Resolution in Thick, Fully-Depleted CCDs withEnhanced Red Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Fairfield, Jessamyn A.

    2005-11-10

    The point spread function (PSF) is an important measure ofspatial resolution in CCDs for point-like objects, since it can affectuse in imaging and spectroscopic applications. We present new data andtheoretical developments in the study of lateral charge diffusion inthick, fully-depleted charge-coupled devices (CCDs) developed at LawrenceBerkeley National Laboratory (LBNL). Because they are fully depleted, theLBNL devices have no field-free region, and diffusion can be controlledthrough the application of an external bias voltage. We give results fora 3512x3512 format, 10.5 ?m pixel back-illuminated p-channel CCDdeveloped for the SuperNova/ Acceleration Probe (SNAP), a proposedsatellite-based experiment designed to study dark energy. The PSF wasmeasured at substrate bias voltages between 3 V and 115 V. At a biasvoltage of 115V, we measure an rms diffusion of 3.7 +- 0.2 ?m. Lateralcharge diffusion in LBNL CCDs is thus expected to meet the SNAPrequirements.

  12. Improved Spatial Resolution in Thick, Fully-Depleted CCDs with Enhanced Red Sensitivity

    International Nuclear Information System (INIS)

    Fairfield, Jessamyn A.

    2005-01-01

    The point spread function (PSF) is an important measure of spatial resolution in CCDs for point-like objects, since it can affect use in imaging and spectroscopic applications. We present new data and theoretical developments in the study of lateral charge diffusion in thick, fully-depleted charge-coupled devices (CCDs) developed at Lawrence Berkeley National Laboratory (LBNL). Because they are fully depleted, the LBNL devices have no field-free region, and diffusion can be controlled through the application of an external bias voltage. We give results for a 3512x3512 format, 10.5 ?m pixel back-illuminated p-channel CCD developed for the SuperNova/Acceleration Probe (SNAP), a proposed satellite-based experiment designed to study dark energy. The PSF was measured at substrate bias voltages between 3 V and 115 V. At a bias voltage of 115V, we measure an rms diffusion of 3.7 ± 0.2 (micro)m. Lateral charge diffusion in LBNL CCDs is thus expected to meet the SNAP requirements

  13. Impact of ACI-ASME code on design and construction of nuclear containment structures

    International Nuclear Information System (INIS)

    Reedy, R.F.

    1978-01-01

    The effect of the ACI-ASME code for design and construction of concrete containment structures on the nuclear and concrete industries is examined. Topics covered include purpose of the code, general requirements, responsibilities and duties, design and construction specifications, quality assurance, inspection, the liner, and stamping

  14. Animal-Computer Interaction (ACI) : An analysis, a perspective, and guidelines

    NARCIS (Netherlands)

    van den Broek, E.L.

    2016-01-01

    Animal-Computer Interaction (ACI)’s founding elements are discussed in relation to its overarching discipline Human-Computer Interaction (HCI). Its basic dimensions are identified: agent, computing machinery, and interaction, and their levels of processing: perceptual, cognitive, and affective.

  15. Chandra Helps Put The Pieces Together On Gamma-Ray Bursts

    Science.gov (United States)

    2000-11-01

    , using Chandra’s High Energy Grating Spectrometer (HETG) in conjunction with the Advanced CCD Imaging Spectrometer (ACIS) on December 18, 1999, for 3.4 hours. The research team included Penn State’s Gordon Garmire, principal investigator for the ACIS instrument, Michael Garcia of the Harvard-Smithsonian Center for Astrophysics, and other colleagues from the United States, Italy, Japan, and the Netherlands. The ACIS X-ray camera was developed for NASA by Penn State and MIT. The High Energy Transmission Grating Spectrometer was built by MIT. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, California, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov

  16. Enhancement of pomalidomide anti-tumor response with ACY-241, a selective HDAC6 inhibitor.

    Directory of Open Access Journals (Sweden)

    Brian J North

    Full Text Available Thalidomide-based Immunomodulatory Drugs (IMiDs®, including lenalidomide and pomalidomide, are effective therapeutics for multiple myeloma. These agents have been approved with, or are under clinical development with, other targeted therapies including proteasome inhibitors, αCD38 monoclonal antibodies, as well as histone deacetylase (HDAC inhibitors for combination therapy. HDAC inhibitors broadly targeting Class I and IIb HDACs have shown potent preclinical efficacy but have frequently demonstrated an undesirable safety profile in combination therapy approaches in clinical studies. Therefore, development of more selective HDAC inhibitors could provide enhanced efficacy with reduced side effects in combination with IMiDs® for the treatment of B-cell malignancies, including multiple myeloma. Here, the second generation selective HDAC6 inhibitor citarinostat (ACY-241, with a more favorable safety profile than non-selective pan-HDAC inhibitors, is shown to synergize with pomalidomide in in vitro assays through promoting greater apoptosis and cell cycle arrest. Furthermore, utilizing a multiple myeloma in vivo murine xenograft model, combination treatment with pomalidomide and ACY-241 leads to increased tumor growth inhibition. At the molecular level, combination treatment with ACY-241 and pomalidomide leads to greater suppression of the pro-survival factors survivin, Myc, and IRF4. The results presented here demonstrate synergy between pomalidomide and ACY-241 in both in vitro and in vivo preclinical models, providing further impetus for clinical development of ACY-241 for use in combination with IMiDs for patients with multiple myeloma and potentially other B-cell malignancies.

  17. Chandra Observations of Hydra A

    Science.gov (United States)

    McNamara, Brian; Lavoie, Anthony R. (Technical Monitor)

    2000-01-01

    We present Chandra X-ray Observations of the Hydra A cluster of galaxies, and we report the discovery of structure in the central 80 kpc of the cluster's X-ray-emitting gas. The most remarkable structures are depressions in the X-ray surface brightness, approx. 25 - 35 kpc diameter, that are coincident with Hydra A's radio lobes. The depressions are nearly devoid of X-ray-emitting gas, and there is no evidence for shock-heated gas surrounding the radio lobes. We suggest the gas within the surface brightness depressions was displaced as the radio lobes expanded subsonically, leaving cavities in the hot atmosphere. The gas temperature declines from 4 keV at 70 kpc to 3 keV in the inner 20 kpc of the brightest cluster galaxy (BCG), and the cooling time of the gas is approx. 600 Myr in the inner 10 kpc. These properties are consistent with the presence of a approx. 34 solar mass/yr cooling flow within a 70 kpc radius. Bright X-ray emission is present in the BCG surrounding a recently-accreted disk of nebular emission and young stars. The star formation rate is commensurate with the cooling rate of the hot gas within the volume of the disk, although the sink for the material that may be cooling at larger radii remains elusive.

  18. THE CHANDRA VARIABLE GUIDE STAR CATALOG

    International Nuclear Information System (INIS)

    Nichols, Joy S.; Lauer, Jennifer L.; Morgan, Douglas L.; Sundheim, Beth A.; Henden, Arne A.; Huenemoerder, David P.; Martin, Eric

    2010-01-01

    Variable stars have been identified among the optical-wavelength light curves of guide stars used for pointing control of the Chandra X-ray Observatory. We present a catalog of these variable stars along with their light curves and ancillary data. Variability was detected to a lower limit of 0.02 mag amplitude in the 4000-10000 A range using the photometrically stable Aspect Camera on board the Chandra spacecraft. The Chandra Variable Guide Star Catalog (VGUIDE) contains 827 stars, of which 586 are classified as definitely variable and 241 are identified as possibly variable. Of the 586 definite variable stars, we believe 319 are new variable star identifications. Types of variables in the catalog include eclipsing binaries, pulsating stars, and rotating stars. The variability was detected during the course of normal verification of each Chandra pointing and results from analysis of over 75,000 guide star light curves from the Chandra mission. The VGUIDE catalog represents data from only about 9 years of the Chandra mission. Future releases of VGUIDE will include newly identified variable guide stars as the mission proceeds. An important advantage of the use of space data to identify and analyze variable stars is the relatively long observations that are available. The Chandra orbit allows for observations up to 2 days in length. Also, guide stars were often used multiple times for Chandra observations, so many of the stars in the VGUIDE catalog have multiple light curves available from various times in the mission. The catalog is presented as both online data associated with this paper and as a public Web interface. Light curves with data at the instrumental time resolution of about 2 s, overplotted with the data binned at 1 ks, can be viewed on the public Web interface and downloaded for further analysis. VGUIDE is a unique project using data collected during the mission that would otherwise be ignored. The stars available for use as Chandra guide stars are

  19. Precision astronomy with imperfect fully depleted CCDs — an introduction and a suggested lexicon

    Science.gov (United States)

    Stubbs, C. W.

    2014-03-01

    This paper summarizes the introductory presentation for a workshop (held Nov 18, 19 2013 at Brookhaven National Laboratory) that explored the challenges associated with making precision astronomical measurements using deeply depleted = ``thick" =``high-ρ'' CCDs. While thick CCDs do provide definite advantages in terms of increased quantum efficiency at wavelengths 700 nm lateral electrical fields within the detector, that produce charge transport anomalies that have been previously misinterpreted as quantum efficiency variations. Performing simplistic flat-fielding therefore introduces systematic errors in the image processing pipeline. One measurement challenge we face is devising a combination of calibration methods and algorithms that can distinguish genuine quantum efficiency variations from charge transport effects. These device imperfections also confront spectroscopic applications, such as line centroid determination for precision radial velocity studies. Given the scientific benefits of improving both the precision and accuracy of astronomical measurements, we need to identify, characterize, and overcome these various detector artifacts. In retrospect, many of the detector features first identified in thick CCDs also afflict measurements made with more traditional CCD detectors, albeit often at a reduced level since the photocharge is subject to the perturbing influence of lateral electric fields for a shorter time interval. I provide a qualitative overview of the physical effects we think are responsible for the observed device properties, and provide some perspective for the work that lies ahead. Finally, I take this opportunity to make a plea for establishing a clear and consistent vocabulary when describing these various detector features, and make some suggestions for a standard lexicon based on discussions at the workshop. A more refined understanding of the device imperfections we are working to circumvent lies ahead, and this workshop was convened

  20. The effect of protons on E2V Technologies L3Vision CCDs

    International Nuclear Information System (INIS)

    Smith, D.R.; Holland, A.D.; Robbins, M.S.

    2003-01-01

    The effect of different 10 MeV equivalent proton fluences on the performance of E2V Technologies (formerly Marconi applied technologies, formerly EEV) L3Vision Charge Coupled Devices (CCDs) was investigated. The first experimental radiation damage results of the L3Vision device are presented, with emphasis given to the analysis of damage to the gain register of the device. Changes in dark current and generation of bright pixels in the CCD image, store, readout register and gain register as a result of proton irradiation are reported and viewed in light of the potential use of the device in space-based applications

  1. Chandra Observations of a Collisionally and Optically Thin Charge Exchange System - Comet 2P/Encke 2003

    Science.gov (United States)

    Christian, D. J.; Lisse, C. M.; Dennerl, K.; Wolk, S. J.; Bodewits, D.; Combi, M. R.; Hoekstra, R.; Makinen, J. T. T.; Weaver, H. A.

    2004-11-01

    The highly favorable perigee passage of the x-ray bright comet 2P/Encke in late 2003 provided an excellent opportunity to use Chandra's high spatial, spectral, and temporal resolution to study cometary x-ray emission in the low neutral target density, low x-ray flux regime. The 1997 ROSAT/EUVE observations of Encke (Lisse et al. 1999) and the nucleus rotation studies of Luu and Jewitt (1990, most likely rotation period = 15 hours) suggested a simple Chandra experiment - continuous ACIS-S observations of Encke over 15 hours during the time of its closest approach to Earth. Here we report initial results from our X-ray observations. X-ray emission from comet Encke was found only in a small, asymmetric region between 1500 km - 40,000 km from the nucleus. The Encke ACIS-S3 200 -- 1000 eV spectrum shows many of the same x-ray emission lines previously observed from comets (C+5, O+6,O+7), including confirmation of several emission lines in the 800 to 1000 eV range. However, the Encke spectrum shows very different line ratios in the 200 - 700 eV range than any previous comet. A lightcurve with peak-to-peak amplitude of 20% and period 11.7 hours was found over the 15 hour observing period. Comparing the observations to contemporaneous measurements of the coma and solar wind made by other means, we find the combination of a low density, collisionally thin (to charge exchange) coma and a post-massive X-flare, high temperature, moderate density solar wind can explain our unusual Encke x-ray observations.

  2. CHANDRA OBSERVATIONS OF COMETS C/2012 S1 (ISON) AND C/2011 L4 (PanSTARRS)

    Energy Technology Data Exchange (ETDEWEB)

    Snios, Bradford; Kharchenko, Vasili [Department of Physics, University of Connecticut, Storrs, CT 06269 (United States); Lisse, Carey M. [Planetary Exploration Group, Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 (United States); Wolk, Scott J. [Chandra X-Ray Observatory Center, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Dennerl, Konrad [Max-Planck-Institut für extraterrestrische Physik, D-85748 Garching (Germany); Combi, Michael R. [Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)

    2016-02-20

    We present our results on the Chandra X-ray Observatory Advanced CCD Imaging Spectrometer (ACIS) observations of the bright Oort Cloud comets C/2012 S1 (ISON) and C/2011 L4 (PanSTARRS). ISON was observed between 2013 October 31–November 06 during variable speed solar wind (SW), and PanSTARRS was observed between 2013 April 17–23 during fast SW. ISON produced an extended parabolic X-ray morphology consistent with a collisionally thick coma, while PanSTARRS demonstrated only a diffuse X-ray-emitting region. We consider these emissions to be from charge exchange (CX) and model each comet's emission spectrum from first principles accordingly. Our model agrees with the observational spectra and also generates composition ratios for heavy, highly charged SW ions interacting with the cometary atmosphere. We compare our derived SW ion compositions to observational data and find a strong agreement between them. These results further demonstrate the utility of CX emissions as a remote diagnostics tool of both astrophysical plasma interaction and SW composition. In addition, we observe potential soft X-ray emissions via ACIS around 0.2 keV from both comets that are correlated in intensity to the hard X-ray emissions between 0.4–1.0 keV. We fit our CX model to these emissions, but our lack of a unique solution at low energies makes it impossible to conclude if they are cometary CX in origin. Finally, we discuss probable emission mechanism sources for the soft X-rays and explore new opportunities these findings present in understanding cometary emission processes via Chandra.

  3. Chandra Scores A Double Bonus With A Distant Quasar

    Science.gov (United States)

    2002-02-01

    Two discoveries from a distant quasar - an enormous X-ray jet and an X-ray shadow cast by an intervening galaxy - are giving astronomers using NASA's Chandra X-ray Observatory cause to be doubly excited. These two independent results reveal information about a supermassive black hole at the center of the quasar as well as the amount of oxygen in a distant galaxy billions of years ago. In one set of Chandra observations of quasar PKS 1127-145, researchers found an X-ray jet that extends over a length of at least a million light years. The jet reveals explosive activity that occurred 10 billion years ago around the quasar's central supermassive black hole. "The X-rays from the jet are likely due to the collision of microwave photons left over from the Big Bang with a high-energy beam of particles," said Aneta Siemiginowska of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, lead author on a paper which will appear in the May 10, 2002 issue of the Astrophysical Journal. "The intensity of these microwaves today is much less than it was 10 billion years ago, due to the expansion of the universe." Chandra observations of quasar PKS 1127-145 demonstrate that scientists can image these jets even though they are billions of light years away. Studies of these extraordinarily large structures will allow astronomers to test models for quasars and the supermassive black holes that power them. The length of the jet and the prominent knots of X-ray emission observed suggest that the activity in the vicinity of the central supermassive black hole is long-lived but maybe intermittent, perhaps due to the mergers of other galaxies with the host galaxy. In a separate result obtained by studying the same quasar, scientists found an X-ray shadow cast by an intervening galaxy. On their way to Earth, the X-rays from PKS 1127-145 pass through a galaxy located about 4 billion light years from Earth, which gives astronomers information about the amount of oxygen in the

  4. The Chandra Source Catalog: Processing and Infrastructure

    Science.gov (United States)

    Evans, Janet; Evans, Ian N.; Glotfelty, Kenny J.; Hain, Roger; Hall, Diane M.; Miller, Joseph B.; Plummer, David A.; Zografou, Panagoula; Primini, Francis A.; Anderson, Craig S.; Bonaventura, Nina R.; Chen, Judy C.; Davis, John E.; Doe, Stephen M.; Fabbiano, Giuseppina; Galle, Elizabeth C.; Gibbs, Danny G., II; Grier, John D.; Harbo, Peter N.; He, Xiang Qun (Helen); Houck, John C.; Karovska, Margarita; Kashyap, Vinay L.; Lauer, Jennifer; McCollough, Michael L.; McDowell, Jonathan C.; Mitschang, Arik W.; Morgan, Douglas L.; Mossman, Amy E.; Nichols, Joy S.; Nowak, Michael A.; Refsdal, Brian L.; Rots, Arnold H.; Siemiginowska, Aneta L.; Sundheim, Beth A.; Tibbetts, Michael S.; van Stone, David W.; Winkelman, Sherry L.

    2009-09-01

    Chandra Source Catalog processing recalibrates each observation using the latest available calibration data, and employs a wavelet-based source detection algorithm to identify all the X-ray sources in the field of view. Source properties are then extracted from each detected source that is a candidate for inclusion in the catalog. Catalog processing is completed by matching sources across multiple observations, merging common detections, and applying quality assurance checks. The Chandra Source Catalog processing system shares a common processing infrastructure and utilizes much of the functionality that is built into the Standard Data Processing (SDP) pipeline system that provides calibrated Chandra data to end-users. Other key components of the catalog processing system have been assembled from the portable CIAO data analysis package. Minimal new software tool development has been required to support the science algorithms needed for catalog production. Since processing pipelines must be instantiated for each detected source, the number of pipelines that are run during catalog construction is a factor of order 100 times larger than for SDP. The increased computational load, and inherent parallel nature of the processing, is handled by distributing the workload across a multi-node Beowulf cluster. Modifications to the SDP automated processing application to support catalog processing, and extensions to Chandra Data Archive software to ingest and retrieve catalog products, complete the upgrades to the infrastructure to support catalog processing.

  5. Harish-Chandra Research Institute, Allahabad

    Indian Academy of Sciences (India)

    The Harish-Chandra Research Institute (known as the Mehta Research Institute of Math- ematics and Mathematical Physics until October 2000) came into existence in 1975, with a donation of some land and Rs. 40 lakhs from the B S Mehta Trust in Calcutta. With the aim of converting it into a top-class research Institute in ...

  6. Chandra Observations of Tycho's Supernova Remnant

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We present a new Chandra observation of Tycho's supernova remnant with the Advanced CCD Imaging Spectrometer. Multicolor X-ray imaging reveals new details of the outer shock and ejecta. At energies between 4 and 6 keV, the outline of the outer shock is clearly revealed in X-rays for the first time.

  7. Chemical Research of Sir Prafulla Chandra Ray

    Indian Academy of Sciences (India)

    Chemical Research of Sir Prafulla Chandra Ray. Sreebrata Goswami and Samaresh Bhattacharya. Sreebrata Goswami is a. Reader at the Department of Inorganic Chemistry,. Indian Association for the. Cultivation of Science,. Calcutta. His major research interests include synthesis of coordination compounds with special.

  8. Fabrication, test and performance of very large X-ray CCDs designed for astrophysical applications

    CERN Document Server

    Soltau, H; Meidinger, N; Stoetter, D; Strüder, L; Trümper, J E; Zanthier, C V; Braeuniger, H; Briel, U; Carathanassis, D; Dennerl, K; Engelhard, S; Haberl, F; Hartmann, R; Hartner, G; Hauff, D; Hippmann, H; Holl, P; Kendziorra, E; Krause, N; Lechner, P; Pfeffermann, E; Popp, M; Reppin, C; Seitz, H; Solc, P; Stadlbauer, T; Weber, U; Weichert, U

    2000-01-01

    A 6x6 cm sup 2 large X-ray CCD has been developed and fabricated at the Semiconductor Laboratory of the Max-Planck-Institut fuer Extraterrestrische Physik. The CCD has been designed for the focal plane cameras of two satellite missions. The concept is a fully depleted pn-CCD which is sensitive over the whole wafer thickness of about 300 mu m. It has been especially developed for X-ray detection delivering a high quantum efficiency over the energy range between 0.2 and 15 keV. A production yield of 27% was achieved. Seven good (almost) defect-free wafers were produced within the performance requirements, i.e. for temperatures below 180 K they show a homogeneous noise level smaller than 5 e sup - , a uniform spectral response with an energy resolution of 130 eV for Mn-K subalpha and a reduction of the sensitive area due to defects by less than 0.3%. Three CCDs have now been integrated in the flight cameras. The presentation comprises special aspects related with the fabrication of very large CCDs, a summary of ...

  9. Fabrication, test and performance of very large X-ray CCDs designed for astrophysical applications

    International Nuclear Information System (INIS)

    Soltau, H.; Kemmer, J.; Meidinger, N.; Stoetter, D.; Strueder, L.; Truemper, J.; Zanthier, C. von; Braeuniger, H.; Briel, U.; Carathanassis, D.; Dennerl, K.; Engelhard, S.; Haberl, F.; Hartmann, R.; Hartner, G.; Hauff, D.; Hippmann, H.; Holl, P.; Kendziorra, E.; Krause, N.; Lechner, P.; Pfeffermann, E.; Popp, M.; Reppin, C.; Seitz, H.; Solc, P.; Stadlbauer, Th.; Weber, U.; Weichert, U.

    2000-01-01

    A 6x6 cm 2 large X-ray CCD has been developed and fabricated at the Semiconductor Laboratory of the Max-Planck-Institut fuer Extraterrestrische Physik. The CCD has been designed for the focal plane cameras of two satellite missions. The concept is a fully depleted pn-CCD which is sensitive over the whole wafer thickness of about 300 μm. It has been especially developed for X-ray detection delivering a high quantum efficiency over the energy range between 0.2 and 15 keV. A production yield of 27% was achieved. Seven good (almost) defect-free wafers were produced within the performance requirements, i.e. for temperatures below 180 K they show a homogeneous noise level smaller than 5 e - , a uniform spectral response with an energy resolution of 130 eV for Mn-K α and a reduction of the sensitive area due to defects by less than 0.3%. Three CCDs have now been integrated in the flight cameras. The presentation comprises special aspects related with the fabrication of very large CCDs, a summary of the performance parameters and results of the qualification procedure of the European and German Space Agencies

  10. Spitzer and Chandra Observations of the Deep Impact Encounter with Comet 9P/Tempel 1

    Science.gov (United States)

    Lisse, C. M.; A'Hearn, M. F.; Belton, M. J. S.; Bodewits, D.; Christian, D. J.; VanCleve, J.; Combi, M.; Dennerl, K.; Farnham, T. L.; Fernandez, Y. R.; Groussin, O.; Hoekstra, R.; Makinen, T.; McFadden, L. A.; Meech, K. J.; Schultz, P.; Weaver, H.; Wolk, S.

    2005-12-01

    On July 4, 2005 NASA's discovery mission Deep Impact (hereafter DI) sent a 375 kg impactor into the nucleus of comet 9P/Tempel 1 at 10.2 km/s relative velocity (A'Hearn et al. 2005). In the IR, Spitzer observed the comet in the unique 5-38 μm spectral range provided by the IRS instrument, allowing direct determination of silicaceous dust, PAHs, carbonates, and aluminum and iron oxides/sulfides in the subsurface material. The Spitzer observations contrasted well with the 1-5 μm spectra obtained by the DI High Resolution Instrument's IR spectrometer and ground based measurements at 1-5 um from the Keck and IRTF observatories (Meech et al. 2005), enabling us to obtain full coverage of the comet's IR spectrum from 1.0 to 38 μm. In the x-ray, the DI experiment allowed for a controlled test of the charge exchange (CXE) emission mechanism that drives cometary x-ray emission (Lisse et al. 2001, Kharchenko and Dalgarno 2001, Krasnopolsky et al. 2002) using observations with the Chandra ACIS-S CCD. The Chandra spectra show a fresh amount of neutral material was injected into a finite volume of the extended atmosphere, or coma, of the comet. In the matter of minutes, this new material directly increased the emission measure for the comet by 30 production from other measurements. Additional contemporaneous measurements by the XMM and SWIFT low energy x-ray imagers provided complimentary lightcurve data points, providing a good long term estimate of the comet's gas emission before, during, and after the Deep Impact encounter. Over the longer term, the combined lightcurves showed evidence of multiple natural outbursts of neutral gas emission from the comet.

  11. NASA's Chandra Finds Evidence for Quasar Ignition

    Science.gov (United States)

    2006-03-01

    New data from NASA's Chandra X-ray Observatory may provide clues to how quasars "turn on." Since the discovery of quasars over 40 years ago, astronomers have been trying to understand the conditions surrounding the birth of these immensely powerful objects. Hot, X-ray producing regions around two distant quasars observed by Chandra are thought to have formed during their activation. These features are located tens of thousands of light years from the central supermassive black holes thought to power the quasars. "The X-ray features are likely shock waves that could be a direct result of the turning on of the quasar about 4 billion years ago," said Alan Stockton of the University of Hawaii in Honolulu, and lead author of a report on this work published recently in The Astrophysical Journal. The quasars, 4C37.43 and 3C249.1, showed no evidence for the existence of a much larger envelope of hot gas around the features, nor were the observed X-ray regions associated with radio waves from the quasars. These factors rule out possible explanations for the X-ray emitting clouds, such as the cooling of hot intergalactic gas, or heating by high-energy jets from the quasars. Chandra X-ray Image of 4C37.43 Chandra X-ray Image of 4C37.43 "The best explanation for our observations is that a burst of star formation, or the activation of the quasar itself, is driving an enormous amount of gas away from the quasar's host galaxy at extremely high speeds," said Hai Fu, a coauthor of the study who is also from the University of Hawaii. Computer simulations of the formation of stars and the growth of black holes during a collision between two galaxies are consistent with this picture. The simulations, performed by Tiziana Di Matteo of Carnegie-Mellon University in Pittsburgh, Pennsylvania, and colleagues, show that the merger of galaxies drives gas toward the central regions where it triggers a burst of star formation and provides fuel for the growth of a central black hole. The inflow

  12. 4th IEEE/ACIS International Conference on Computer and Information Science

    CERN Document Server

    2016-01-01

    This edited book presents scientific results of the 14th IEEE/ACIS International Conference on Computer and Information Science (ICIS 2015) which was held on June 28 – July 1, 2015 in Las Vegas, USA. The aim of this conference was to bring together researchers and scientists, businessmen and entrepreneurs, teachers, engineers, computer users, and students to discuss the numerous fields of computer science and to share their experiences and exchange new ideas and information in a meaningful way. Research results about all aspects (theory, applications and tools) of computer and information science, and to discuss the practical challenges encountered along the way and the solutions adopted to solve them.

  13. APC implementation in Chandra Asri - ethylene plant

    Science.gov (United States)

    Sidiq, Mochamad; Mustofa, Ali

    2017-05-01

    Nowadays, the modern process plants are continuously improved for maximizing production, Optimization of the energy and raw material and reducing the risk. Due to many disturbances appearance between the process units, hence, the failure of one unit might have a bad effect on the overall productivity. Ethylene Plant have significant opportunities for using Advanced Process Control (APC) technologies to improve operation stability, push closer to quality or equipment limit, and improve the capability of process units to handle disturbances. APC implementation had considered a best answer for solving multivariable control problem. PT. Chandra Asri Petrochemical, Tbk (CAP) operates a large naphtha cracker complex at Cilegon, Indonesia. To optimize the plant operation and to enhance the benefit, Chandra Asri has been decided to implement Advance Process Control (APC) for ethylene plant. The APC implementation technology scopes at CAP are as follows: 1. Hot Section : Furnaces, Quench Tower 2. Cold Section : Demethanizer, Deethanizer, Acetylene Converter, Ethylene Fractionator, Depropanizer, Propylene Fractionator, Debutanizer

  14. Study of the behavior of commercial CCDs images sensors in a space environment

    International Nuclear Information System (INIS)

    Nuns, Thierry

    2002-01-01

    We studied the behavior of CCD images sensors exposed to a spatial radiative constraint. The aim of this work is to compare the degradation of the sensitive parameters between commercial components and hardened ones. It appears that the dark current density of commercial CCDs is sensitive to total dose. This parameter is the main source of degradation for dose levels up to 200 Gy(Si). The induced oxide charge is the prime responsible for this behavior as shown by the partial annealing of the dark current under 100 C heating. It is shown that this charge deposited in isolation oxides induces an inversion zone at the semiconductor surface leading to the creation of a parasitic transistor. Numerical simulations show the thermal activation of the leakage currents due to this structure, and confirm the experimental observations. The irradiation of CCD with particles generating bulk defaults like protons and neutrons leads to the observation of a dark current increase induced by the contribution of elastic (for protons) and inelastic interactions between incident particles and semiconductor atoms. The associated total dose deposition (proton) provides an additional contribution to the mean degradation. The occurrence of pixels with a large RTS and the increase of the charge transfer inefficiency (CTI) can also be noticed. In a hardness assurance context, this work provides a better understanding of the critical points, which have to be taken into account in order to propose a good estimation of the CCD degradation for a spatial application. We should keep in mind the predominant role of leakage currents that directly affect the measurement of the conversion factor or the CTI. This behavior differs from the one observed with hardened CCDs. The characterization of commercial sensors under total dose is proving to be mandatory, as well as the estimation of the number of pixels with a large dark current and the probability of RTS occurrence in case of non ionising effects

  15. Soft X-ray radiation damage in EM-CCDs used for Resonant Inelastic X-ray Scattering

    Science.gov (United States)

    Gopinath, D.; Soman, M.; Holland, A.; Keelan, J.; Hall, D.; Holland, K.; Colebrook, D.

    2018-02-01

    Advancement in synchrotron and free electron laser facilities means that X-ray beams with higher intensity than ever before are being created. The high brilliance of the X-ray beam, as well as the ability to use a range of X-ray energies, means that they can be used in a wide range of applications. One such application is Resonant Inelastic X-ray Scattering (RIXS). RIXS uses the intense and tuneable X-ray beams in order to investigate the electronic structure of materials. The photons are focused onto a sample material and the scattered X-ray beam is diffracted off a high resolution grating to disperse the X-ray energies onto a position sensitive detector. Whilst several factors affect the total system energy resolution, the performance of RIXS experiments can be limited by the spatial resolution of the detector used. Electron-Multiplying CCDs (EM-CCDs) at high gain in combination with centroiding of the photon charge cloud across several detector pixels can lead to sub-pixel spatial resolution of 2-3 μm. X-ray radiation can cause damage to CCDs through ionisation damage resulting in increases in dark current and/or a shift in flat band voltage. Understanding the effect of radiation damage on EM-CCDs is important in order to predict lifetime as well as the change in performance over time. Two CCD-97s were taken to PTB at BESSY II and irradiated with large doses of soft X-rays in order to probe the front and back surfaces of the device. The dark current was shown to decay over time with two different exponential components to it. This paper will discuss the use of EM-CCDs for readout of RIXS spectrometers, and limitations on spatial resolution, together with any limitations on instrument use which may arise from X-ray-induced radiation damage.

  16. Tamoxifen induces regression of estradiol-induced mammary cancer in the ACI.COP-Ept2 rat model.

    Science.gov (United States)

    Ruhlen, Rachel L; Willbrand, Dana M; Besch-Williford, Cynthia L; Ma, Lixin; Shull, James D; Sauter, Edward R

    2009-10-01

    The ACI rat is a unique model of human breast cancer in that mammary cancers are induced by estrogen without carcinogens, irradiation, xenografts or transgenic manipulations. We sought to characterize mammary cancers in a congenic variant of the ACI rat, the ACI.COP-Ept2. All rats with estradiol implants developed mammary cancers in 5-7 months. Rats bearing estradiol-induced mammary cancers were treated with tamoxifen for three weeks. Tamoxifen reduced tumor mass, measured by magnetic resonance imaging, by 89%. Tumors expressed estrogen receptors (ER), progesterone receptor (PR), and Erbb2. ERalpha and PR were overexpressed in tumor compared to adjacent non-tumor mammary gland. Thus, this model is highly relevant to hormone responsive human breast cancers.

  17. NASA's Chandra Sees Brightest Supernova Ever

    Science.gov (United States)

    2007-05-01

    WASHINGTON - The brightest stellar explosion ever recorded may be a long-sought new type of supernova, according to observations by NASA's Chandra X-ray Observatory and ground-based optical telescopes. This discovery indicates that violent explosions of extremely massive stars were relatively common in the early universe, and that a similar explosion may be ready to go off in our own galaxy. "This was a truly monstrous explosion, a hundred times more energetic than a typical supernova," said Nathan Smith of the University of California at Berkeley, who led a team of astronomers from California and the University of Texas in Austin. "That means the star that exploded might have been as massive as a star can get, about 150 times that of our sun. We've never seen that before." Chandra X-ray Image of SN 2006gy Chandra X-ray Image of SN 2006gy Astronomers think many of the first generation of stars were this massive, and this new supernova may thus provide a rare glimpse of how the first stars died. It is unprecedented, however, to find such a massive star and witness its death. The discovery of the supernova, known as SN 2006gy, provides evidence that the death of such massive stars is fundamentally different from theoretical predictions. "Of all exploding stars ever observed, this was the king," said Alex Filippenko, leader of the ground-based observations at the Lick Observatory at Mt. Hamilton, Calif., and the Keck Observatory in Mauna Kea, Hawaii. "We were astonished to see how bright it got, and how long it lasted." The Chandra observation allowed the team to rule out the most likely alternative explanation for the supernova: that a white dwarf star with a mass only slightly higher than the sun exploded into a dense, hydrogen-rich environment. In that event, SN 2006gy should have been 1,000 times brighter in X-rays than what Chandra detected. Animation of SN 2006gy Animation of SN 2006gy "This provides strong evidence that SN 2006gy was, in fact, the death of an

  18. Synergistic effect of radiation on colon carcinogenesis induced by methylazoxymethanol acetate in ACI/N rats

    International Nuclear Information System (INIS)

    Tanaka, Takuji; Morishita, Yukio; Kawamori, Toshihiko; Suzui, Masumi; Kojima, Toshihiro; Sugie, Shigeyuki; Mori, Hideki

    1993-01-01

    The effect on colon and liver carcinogenicity in rats of a single X-irradiation exposure given either before or after methylazoxymethanol (MAM) acetate was studied in ACI/N rats of both sexes. A single dose of X-irradiation (3 Gy) was administered either 3 months before or after three weekly s.c. injection of MAM acetate (25 mg/kg body weight). At 365 days after the start, the incidence and multiplicity of MAM acetate-induced intestinal tumors were enhanced by X-irradiation either prior to or after the MAM acetate treatment. In addition, X-irradiation before MAM acetate increased the incidence of hepatocellular foci in either sex. In females, X-irradiation either before or after MAM acetate exposure decreased intestinal tumorigenesis. These findings suggest an apparent synergism of these agents in intestinal carcinogenesis of male rats. (author)

  19. 3th IEEE/ACIS International Conference on Computer and Information Science

    CERN Document Server

    2015-01-01

    This edited book presents scientific results of the 13th IEEE/ACIS International Conference on Computer and Information Science (ICIS 2014) which was held on June 4-6, 2014 in Taiyuan, China. The aim of this conference was to bring together researchers and scientists, businessmen and entrepreneurs, teachers, engineers, computer users, and students to discuss the numerous fields of computer science and to share their experiences and exchange new ideas and information in a meaningful way. Research results about all aspects (theory, applications and tools) of computer and information science, and to discuss the practical challenges encountered along the way and the solutions adopted to solve them. The conference organizers selected the best papers from those papers accepted for presentation at the conference.  The papers were chosen based on review scores submitted by members of the program committee, and underwent further rigorous rounds of review. This publication captures 14 of the conference’s most promis...

  20. Acharya Prafulla Chandra at the College of Science

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 1. Acharya Prafulla Chandra at the College of Science. Gurunath ... Author Affiliations. Gurunath Mukherjee1. Department of Chemistry University College of Science & Technology 92, Acharya Prafulla Chandra Road Calcutta 700 009, India.

  1. Acharya Prafulla Chandra at the College of Science

    Indian Academy of Sciences (India)

    Prafulla Chandra's charity. Upon completing sixty in 1921,. Prafulla Chandra made a gift of his entire salary from that time onward to the University with the stipulation that the accumu- lated money should be spent for extension and development of the Department of Chemistry in the College of Science and for the creation of ...

  2. Metal contamination analysis of the epitaxial starting material for scientific CCDs

    CERN Document Server

    Krause, N; Hauff, D; Kemmer, J; Stoetter, D; Strüder, L; Weber, J

    2000-01-01

    Traces of unintentionally introduced titanium into a 3 k OMEGA cm float-zone epitaxial silicon at ultra low levels of 10 sup 1 sup 0 cm sup - sup 3 were found to be the origin of charge transfer loss in pn-CCDs. We identified and backtracked the titanium impurity. The full-depletion design of the pn-CCD, a thin entrance window at the back of the CCD and the low oxygen content of the float-zone material allow no common gettering step. Titanium is introduced into the wafer during the epitaxy process. This is independent of the reactor and the producer of the epitaxial silicon and seems to be a common epitaxy-related problem. To identify the impurity, electron emission rates of traps were measured by means of the CCD. The data were compared with emission rates of identical material obtained by standard-DLTS. The data agree well with literature data of the titanium acceptor level and the titanium donor level. An analysis of the capture cross section by means of the CCD gives a high electron capture cross section....

  3. The X-ray quantum efficiency measurement of high resistivity CCDs

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Neil J. [Imaging for Space and Terrestrial Applications, School of Engineering and Design, Brunel University, Uxbridge, UB8 3PH (United Kingdom); e2v centre for electronic imaging, Planetary and Space Sciences Research Institute, The Open University, Milton Keynes, MK7 6AA (United Kingdom)], E-mail: n.j.murray@open.ac.uk; Holland, Andrew D. [e2v centre for electronic imaging, Planetary and Space Sciences Research Institute, The Open University, Milton Keynes, MK7 6AA (United Kingdom); Smith, David R.; Gow, Jason P. [Imaging for Space and Terrestrial Applications, School of Engineering and Design, Brunel University, Uxbridge, UB8 3PH (United Kingdom); Pool, Peter J.; Burt, David J. [e2v technologies plc, 106 Waterhouse Lane, Chelmsford, CM1 2QU (United Kingdom)

    2009-06-01

    The CCD247 is the second generation of high-resistivity device to be manufactured in e2v technologies plc development programme. Intended for infrared astronomy, the latest devices are fabricated on high resistivity ({approx}8 k{omega} cm) bulk silicon, allowing for a greater device thickness whilst maintaining full depletion when 'thinned' to a thickness of 150 {mu}m. In the case of the front illuminated variant, depletion of up to 300 {mu}m is achievable by applying a gate to substrate potential of up to 120 V, whilst retaining adequate spectral performance. The increased depletion depth of high-resistivity CCDs greatly improves the quantum efficiency (QE) for incident X-ray photons of energies above 5 keV, making such a device beneficial in future X-ray astronomy missions and other applications. Here we describe the experimental setup and present results of X-ray QE measurements taken in the energy range 2-20 keV for a front illuminated CCD247, showing QE in excess of 80% at 10 keV. Results for the first generation CCD217 and swept-charge device (1500 {omega} cm epitaxial silicon) are also presented.

  4. Characterization of orthogonal transfer array CCDs for the WIYN one degree imager

    Science.gov (United States)

    Lesser, Michael; Ouellette, David; Boroson, Todd; Harbeck, Daniel; Martin, Pierre; Jacoby, George; Cavin, John; Sawyer, David; Boggs, Kasey; Bredthauer, Richard

    2012-03-01

    The WIYN One Degree Imager (ODI) will provide a one degree field of view for the WIYN 3.5 m telescope located on Kitt Peak near Tucson, Arizona. Its focal plane consists of an 8x8 grid of Orthogonal Transfer Array (OTA) CCD detectors. These detectors are the STA2200 OTA CCDs designed and fabricated by Semiconductor Technology Associates, Inc. and backside processed at the University of Arizona Imaging Technology Laboratory. Several lot runs of the STA2200 detectors have been fabricated. We have backside processed devices from these different lots and provide detector performance characterization, including noise, CTE, cosmetics, quantum efficiency, and some orthogonal transfer characteristics. We discuss the performance differences for the devices with different silicon thickness and resistivity. A fully buttable custom detector package has been developed for this project which allows hybridization of the silicon detectors directly onto an aluminum nitride substrate with an embedded pin grid array. This package is mounted on a silicon-aluminum alloy which provides a flat imaging surface of less than 20 microns peakvalley at the -100 C operating temperature. Characterization of the package performance, including low temperature profilometry, is described in this paper.

  5. A Novel Method to Remove Fringes for Dispersive Hyperspectral VNIR Imagers Using Back-Illuminated CCDs

    Directory of Open Access Journals (Sweden)

    Binlin Hu

    2018-01-01

    Full Text Available Dispersive hyperspectral VNIR (visible and near-infrared imagers using back-illuminated CCDs will suffer from interference fringes in near-infrared bands, which can cause a sensitivity modulation as high as 40% or more when the spectral resolution gets higher than 5 nm. In addition to the interference fringes that will change with time, there is fixed-pattern non-uniformity between pixels in the spatial dimension due to the small-scale roughness of the imager’s entrance slit, creating a much more complicated problem. A two-step method to remove fringes for dispersive hyperspectral VNIR imagers is proposed and evaluated. It first uses a ridge regression model to suppress the spectral fringes, and then computes spatial correction coefficients from the object data to correct the spatial fringes. In order to evaluate its effectiveness, the method was used to remove fringes for both the calibration data and object data collected from two VNIR grating-based hyperspectral imagers. Results show that the proposed method can preserve the original spectral shape, improve the image quality, and reduce the fringe amplitude in the 700–1000 nm region from about ±23% (10.7% RMSE to about ±4% (1.9% RMSE. This method is particularly useful for spectra taken through a slit with a grating and shows flexible adaptability to object data, which suffer from time-varying interference fringes.

  6. Taking the CCDs to the ultimate performance for low threshold experiments

    Energy Technology Data Exchange (ETDEWEB)

    Haro, Miguel [Centro Atomico Bariloche; Moroni, Guillermo [Bahia Blanca, U. Natl. Del Sur; Tiffenberg, Javier [Fermilab; Cancelo, Gustavo [Fermilab; Estrada, Juan [Tokyo, Natl. Aerosp. Lab.; Bertou, Xavier [Centro Atomico Bariloche; Paolini, Eduardo [Bahia Blanca, U. Natl. Del Sur

    2016-11-14

    Scientific grade CCDs show atractive capabilities for the detection of particles with small energy deposition in matter. Their very low threshold of approximately 40 eV and their good spatial reconstruction of the event are key properties for currently running experiments: CONNIE and DAMIC. Both experiments can benefit from any increase of the detection efficiency of nuclear recoils at low energy. In this work we present two different approaches to increase this efficiency by increasing the SNR of events. The first one is based on the reduction of the readout noise of the device, which is the main contribution of uncertainty to the signal measurement. New studies on the electronic noise from the integrated output amplifier and the readout electronics will be presented together with result of a new configuration showing a lower limit on the readout noise which can be implemented on the current setup of the CCD based experiments. A second approach to increase the SNR of events at low energy that will be presented is the studies of the spatial conformation of nuclear recoil events at different depth in the active volume by studies of new effects that differ from expected models based on not interacting diffusion model of electrons in the semiconductor.

  7. Design of an Image-Servo Mask Alignment System Using Dual CCDs with an XXY Stage

    Directory of Open Access Journals (Sweden)

    Chih-Jer Lin

    2016-02-01

    Full Text Available Mask alignment of photolithography technology is used in many applications, such as micro electro mechanical systems’ semiconductor process, printed circuits board, and flat panel display. As the dimensions of the product are getting smaller and smaller, the automatic mask alignment of photolithography is becoming more and more important. The traditional stacked XY-Θz stage is heavy and it has cumulative flatness errors due to its stacked assembly mechanism. The XXY stage has smaller cumulative error due to its coplanar design and it can move faster than the traditional XY-Θz stage. However, the relationship between the XXY stage’s movement and the commands of the three motors is difficult to compute, because the movements of the three motors on the same plane are coupling. Therefore, an artificial neural network is studied to establish a nonlinear mapping from the desired position and orientation of the stage to three motors’ commands. Further, this paper proposes an image-servo automatic mask alignment system, which consists of a coplanar XXY stage, dual GIGA-E CCDs with lens and a programmable automatic controller (PAC. Before preforming the compensation, a self-developed visual-servo provides the positioning information which is obtained from the image processing and pattern recognition according to the specified fiducial marks. To obtain better precision, two methods including the center of gravity method and the generalize Hough Transformation are studied to correct the shift positioning error.

  8. The Stability of Chandra Telescope Pointing and Spacial Resolution

    Science.gov (United States)

    Zhao, Ping

    2018-01-01

    Chandra X-ray Observatory revolutionized the X-ray astronomy as being the first, and so far the only, X-ray telescope achieving sub-arcsecond spacial resolution. Chandra is comprised of three principal elements: the High Resolution Mirror Assembly (HRMA), Pointing Control and Aspect Determination (PCAD) system, and the Science Instrument Module (SIM), which is where the X-ray detectors mounted and is connected to the HRMA by a 10-meter long Optical Bench Assembly. To achieve and retain the unprecedented imaging quality, it is critical that these three principal elements to stay rigid and stable for the entire life time of the Chandra operation. I will review the issues of telescope pointing stability, optical Axis, aimpoint and their impacts to the Chandra operation, and evaluate the integrity and stability of the telescope. I will show images taken from all four detectors since launch to demonstrate the quality and stability of the Chandra spacial resolution.

  9. Synthesis and characterization of C@CdS dots in aqueous solution and their application in labeling human gastric carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Wei, E-mail: dongwei5873@126.com [Shenyang Medical College, Department of Chemistry (China); Zhou, Siqi [Fengtian Hospital Affiliated to Shenyang Medical College, ICU (China); Dong, Yan [Shenyang Pharmaceutical University, Experiment Center of Traditional Chinese Medicine Department (China); Wang, Jingwen; Liu, Shuang; Zhu, Pengxia [Shenyang Medical College, Department of Chemistry (China)

    2015-03-15

    Colloidal carbon spheres coated with cadmium sulfide nanoparticle quantum dots (C@CdS dots) with the particle size smaller than 50 nm were synthesized by an aqueous approach. The effects of different reaction times, temperatures, and pH values were carefully investigated to optimize the synthesis conditions. The as-prepared C@CdS dots were linked with mouse anti-human carcinoembryonic antigen antibody and goat anti-mouse immunoglobulin (IgG) to directly and indirectly label fixed human gastric carcinoma cells, respectively. The cytotoxicity of the C@CdS dots was also tested using the human gastric carcinoma cells. No apparent cytotoxicity was observed, which suggested the potential application of the as-prepared C@CdS dots in bioimaging.

  10. Synthesis and characterization of C@CdS dots in aqueous solution and their application in labeling human gastric carcinoma cells

    Science.gov (United States)

    Dong, Wei; Zhou, Siqi; Dong, Yan; Wang, Jingwen; Liu, Shuang; Zhu, Pengxia

    2015-03-01

    Colloidal carbon spheres coated with cadmium sulfide nanoparticle quantum dots (C@CdS dots) with the particle size smaller than 50 nm were synthesized by an aqueous approach. The effects of different reaction times, temperatures, and pH values were carefully investigated to optimize the synthesis conditions. The as-prepared C@CdS dots were linked with mouse anti-human carcinoembryonic antigen antibody and goat anti-mouse immunoglobulin (IgG) to directly and indirectly label fixed human gastric carcinoma cells, respectively. The cytotoxicity of the C@CdS dots was also tested using the human gastric carcinoma cells. No apparent cytotoxicity was observed, which suggested the potential application of the as-prepared C@CdS dots in bioimaging.

  11. X-raying galaxies: a Chandra legacy.

    Science.gov (United States)

    Wang, Q Daniel

    2010-04-20

    This presentation reviews Chandra's major contribution to the understanding of nearby galaxies. After a brief summary on significant advances in characterizing various types of discrete x-ray sources, the presentation focuses on the global hot gas in and around galaxies, especially normal ones like our own. The hot gas is a product of stellar and active galactic nuclear feedback--the least understood part in theories of galaxy formation and evolution. Chandra observations have led to the first characterization of the spatial, thermal, chemical, and kinetic properties of the gas in our galaxy. The gas is concentrated around the galactic bulge and disk on scales of a few kiloparsec. The column density of chemically enriched hot gas on larger scales is at least an order magnitude smaller, indicating that it may not account for the bulk of the missing baryon matter predicted for the galactic halo according to the standard cosmology. Similar results have also been obtained for other nearby galaxies. The x-ray emission from hot gas is well correlated with the star formation rate and stellar mass, indicating that the heating is primarily due to the stellar feedback. However, the observed x-ray luminosity of the gas is typically less than a few percent of the feedback energy. Thus the bulk of the feedback (including injected heavy elements) is likely lost in galaxy-wide outflows. The results are compared with simulations of the feedback to infer its dynamics and interplay with the circumgalactic medium, hence the evolution of galaxies.

  12. Doing Science with the Chandra Source Catalog

    Science.gov (United States)

    Evans, Ian N.; Chandra Source Catalog Team

    2018-01-01

    The excellent spatial resolution (~1 arcsecond on-axis) of the Chandra X-ray Observatory, combined with a reasonable field of view and low instrumental backgrounds, allow detection of serendipitous X-ray sources with a high detectable-source density with low confusion. The aim of the Chandra Source Catalog (CSC) is to disseminate this wealth of information to the user community in a form that is immediately usable for scientific investigation, and the catalog is intended to satisfy the needs of a broad- based group of scientists, including those who may be less familiar with astronomical data analysis in the X-ray regime.The second major release of the catalog, CSC 2.0, will be made available to the user community in early 2018, and preliminary lists of detections and sources are available now. CSC 2.0 will roughly triple the size of the current version of the catalog to an estimated 375,000 detections, corresponding to ~315,000 unique X-ray sources on the sky. For each detected X-ray source, the catalog provides a detailed set of properties including the source position and associated position error ellipse, source extent, multi-band aperture photometry probability density functions, spectral fits using several source models, hardness ratios, and intra- and inter-observation temporal variability measures. All numerical measures have associated two-sided confidence intervals. In addition to tabular data, the catalog provides FITS data products that are immediately suitable for further user analysis, including per-field and per-source images, photon event lists, responses, spectra, and light curves.We describe the content and organization of the catalog in more detail, discuss the analyses that were performed to extract the measured source properties, and demonstrate how the catalog content can be immediately and effectively utilized for scientific investigations. This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical

  13. The Chandra Cygnus OB2 Survey

    Science.gov (United States)

    Drake, Jeremy

    2009-09-01

    Understanding massive "starburst" clusters is crucial for the first stars, starburst galaxies, galactic and ISM evolution, and star and planet formation on universal and galactic scales. But Galactic superclusters are generally too distant for detailed study. Recent awareness that Cygnus OB2 (1.5kpc; ~2Myr old) has supercluster characteristics has sparked a multiwavelength legacy effort exploiting its proximity to study starburst astrophysics. This Chandra Legacy project will provide an exquisite vision of the anatomy of a massive "collapse" mode of star formation, allowing detailed archeology of its history and content. 8000-10000 detections down to 0.1Msun will incisively test theories of giant molecular cloud collapse, massive star formation and protoplanetary disk evolution.

  14. Chandra Survey of Nearby Galaxies: The Catalog

    Energy Technology Data Exchange (ETDEWEB)

    She, Rui; Feng, Hua [Department of Engineering Physics and Center for Astrophysics, Tsinghua University, Beijing 100084 (China); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100087 (China)

    2017-02-01

    We searched the public archive of the Chandra X-ray Observatory as of 2016 March and assembled a sample of 719 galaxies within 50 Mpc with available Advanced CCD Imaging Spectrometer observations. By cross-correlation with the optical or near-infrared nuclei of these galaxies, 314 of them are identified to have an X-ray active galactic nucleus (AGN). The majority of them are low-luminosity AGNs and are unlikely X-ray binaries based upon their spatial distribution and luminosity functions. The AGN fraction is around 60% for elliptical galaxies and early-type spirals, but drops to roughly 20% for Sc and later types, consistent with previous findings in the optical. However, the X-ray survey is more powerful in finding weak AGNs, especially from regions with active star formation that may mask the optical AGN signature. For example, 31% of the H ii nuclei are found to harbor an X-ray AGN. For most objects, a single power-law model subject to interstellar absorption is adequate to fit the spectrum, and the typical photon index is found to be around 1.8. For galaxies with a non-detection, their stacked Chandra image shows an X-ray excess with a luminosity of a few times 10{sup 37} erg s{sup −1} on average around the nuclear region, possibly composed of faint X-ray binaries. This paper reports on the technique and results of the survey; in-depth analysis and discussion of the results will be reported in forthcoming papers.

  15. Imbalance between apoptosis and cell proliferation during early stages of mammary gland carcinogenesis in ACI rats

    International Nuclear Information System (INIS)

    Kutanzi, Kristy R.; Koturbash, Igor; Bronson, Roderick T.; Pogribny, Igor P.; Kovalchuk, Olga

    2010-01-01

    Estrogen and ionizing radiation are well-documented human breast carcinogens, yet the exact mechanisms of their deleterious effects on mammary gland remain to be discerned. Here we analyze the balance between cellular proliferation and apoptosis in the mammary glands of rats exposed to estrogen and X-ray radiation and the combined action of these carcinogenic agents. For the first time, we show that combined exposure to estrogen and radiation has a synergistic effect on cell proliferation in the mammary glands of ACI rats, as evidenced by a substantially greater magnitude of cell proliferation, especially after 12 and 18 weeks of treatment, when compared to mammary glands of rats exposed to estrogen or radiation alone. We also demonstrate that an imbalance between cell proliferation and apoptosis, rather than enhanced cell proliferation or apoptosis suppression alone, may be a driving force for carcinogenesis. Our studies further suggest that compromised functional activity of p53 may be one of the mechanisms responsible for the proliferation/apoptosis imbalance. In sum, the results of our study indicate that evaluation of the extent of cell proliferation and apoptosis before the onset of preneoplastic lesions may be a potential biomarker of breast cancer risk after exposure to breast carcinogens.

  16. The Chandra Deep Field-South Survey: 7 Ms Source Catalogs

    Science.gov (United States)

    Luo, B.; Brandt, W. N.; Xue, Y. Q.; Lehmer, B.; Alexander, D. M.; Bauer, F. E.; Vito, F.; Yang, G.; Basu-Zych, A. R.; Comastri, A.; hide

    2016-01-01

    We present X-ray source catalogs for the approx. 7 Ms exposure of the Chandra Deep Field-South (CDF-S), which covers a total area of 484.2 arcmin2. Utilizing WAVDETECT for initial source detection and ACIS Extract for photometric extraction and significance assessment, we create a main source catalog containing 1008 sources that are detected in up to three X-ray bands: 0.5-7.0 keV, 0.5-2.0 keV, and 2-7 keV. A supplementary source catalog is also provided, including 47 lower-significance sources that have bright (Ks catalog sources, and we collect redshifts for 986 of these sources, including 653 spectroscopic redshifts and 333 photometric redshifts. Based on the X-ray and multiwavelength properties, we identify 711 active galactic nuclei (AGNs) from the main-catalog sources. Compared to the previous approx. 4 Ms CDF-S catalogs, 291 of the main-catalog sources are new detections. We have achieved unprecedented X-ray sensitivity with average flux limits over the central approx. 1 arcmin2 region of 1.9 x 10(exp -17), 6.4 x 10(exp -18), and 2.7 x 10(exp -17) erg/sq cm/s in the three X-ray bands, respectively. We provide cumulative number-count measurements observing, for the first time, that normal galaxies start to dominate the X-ray source population at the faintest 0.5-2.0 keV flux levels. The highest X-ray source density reaches approx. 50,500/sq deg, and 47% +/- 4 of these sources are AGNs (approx. 23,900/sq deg).

  17. Observations of the Jovian System with the Chandra X-Ray Observatory

    Science.gov (United States)

    Elsner, R. F.; Tennant, A. F.; Weisskopf, M. C.; Gladstone, G. R.; Waite, J. H.; Crary, F. J.; Grodent, D.; Howell, R. R.; Johnson, R. E.; Bhardwaj, A.; hide

    2002-01-01

    The {\\sl Chandra X-ray Observatory) observed the Jovian system on 25-26 Nov 1999 with the Advanced CCD Imaging Spectrometer (ACIS), in support of the Galileo flyby of Io, and on 18 Dec 2000 with the imaging array of the High Resolution Camera (HRC-I), in support of the Cassini flyby of Jupiter. These sensitive, very high spatial-resolution X-ray observations have revealed that Jupiter's northern x-ray aurora originates at a spot fixed in a coordinate system rotating with the planet at latitude (60--70 deg north) and longitude (160--180 deg System III). Contrary to previous expectations, this location is poleward of the main FUV auroral oval and the foot of the Io Flux Tube, and is apparently connected magnetically to a region of the outer magnetosphere beyond $\\sim$30 Jupiter radii. The northern auroral x-ray emission varies with a period $\\sim$45 minute and has a an average power of $\\sim$1 GW. The earlier view that Jupiter's x-ray aurora resulted from the precipitation of heavy ions from the outer edge of the lo Plasma Torus is now in doubt. Jupiter's disk also emits x-rays with a power of $\\sim$2 GW, perhaps resulting from reprocessing of solar x-rays in its atmosphere. These observations reveal for the first time x-ray emission from the Io Plasma Torus, with a power of $\\sim$0.1 Gw. The origin of this emission is not currently understood, although bremmstrahlung from non-thermal electrons may play a significant role. Finally, we report the discovery of very faint ($\\sim$1--2 MW) soft x-ray emission from the Galilean satellites Io, Europa, and probably Ganymede, most likely as a result of bombardment of their surfaces by energetic ($ greater than $10 keV) H, O, and S ions from the region of the Io Plasma Torus.

  18. A VERY DEEP CHANDRA OBSERVATION OF A1795: THE COLD FRONT AND COOLING WAKE

    Energy Technology Data Exchange (ETDEWEB)

    Ehlert, Steven; McDonald, Michael; Miller, Eric D.; Bautz, Mark W. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); David, Laurence P., E-mail: sehlert@space.mit.edu [Harvard-Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-02-01

    We present a new analysis of very deep Chandra observations of the galaxy cluster A1795. Utilizing nearly 750 ks of net ACIS imaging, we are able to resolve the thermodynamic structure of the intracluster medium (ICM) on length scales of ∼1 kpc near the cool core. We find several previously unresolved structures, including a high pressure feature to the north of the Brightest Cluster Galaxy (BCG) that appears to arise from the bulk motion of A1795's cool core. To the south of the cool core, we find low temperature (∼3 keV), diffuse ICM gas extending for distances of ∼50 kpc spatially coincident with previously identified filaments of Hα emission. Gas at similar temperatures is also detected in adjacent regions without any Hα emission. The X-ray gas coincident with the Hα filament has been measured to be cooling spectroscopically at a rate of ∼1 M{sub ⊙} yr{sup −1}, consistent with measurements of the star formation rate in this region as inferred from ultraviolet (UV) observations, suggesting that the star formation in this filament as inferred by its Hα and UV emission can trace its origin to the rapid cooling of dense, X-ray emitting gas. The Hα filament is not a unique site of cooler ICM, however, as ICM at similar temperatures and even higher metallicities not cospatial with Hα emission is observed just to the west of the Hα filament, suggesting that it may have been uplifted by A1795's central active galaxy. Further simulations of cool core sloshing and active galactic nucleus feedback operating in concert with one another will be necessary to understand how such a dynamic cool core region may have originated and why the Hα emission is so localized with respect to the cool X-ray gas.

  19. Jagadis Chandra Bose and His Pioneering Research on Microwaves

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 12. Jagadis Chandra Bose and His Pioneering Research on Microwaves. C George Verghese George C Verghese. Volume 10 Issue 12 December 2005 pp 83-85 ...

  20. Combined autologous chondrocyte implantation (ACI with supra-condylar femoral varus osteotomy, following lateral growth-plate damage in an adolescent knee: 8-year follow-up

    Directory of Open Access Journals (Sweden)

    Vijayan Sridhar

    2011-03-01

    Full Text Available Abstract We report the 8-year clinical and radiographic outcome of an adolescent patient with a large osteochondral defect of the lateral femoral condyle, and ipsilateral genu valgum secondary to an epiphyseal injury, managed with autologous chondrocyte implantation (ACI and supracondylar re-alignment femoral osteotomy. Long-term clinical success was achieved using this method, illustrating the effective use of re-alignment osteotomy in correcting mal-alignment of the knee, protecting the ACI graft site and providing the optimum environment for cartilage repair and regeneration. This is the first report of the combined use of ACI and femoral osteotomy for such a case.

  1. THE CHANDRA M101 MEGASECOND: DIFFUSE EMISSION

    International Nuclear Information System (INIS)

    Kuntz, K. D.; Snowden, S. L.

    2010-01-01

    Because M101 is nearly face-on, it provides an excellent laboratory in which to study the distribution of X-ray-emitting gas in a typical late-type spiral galaxy. We obtained a Chandra observation with a cumulative exposure of roughly 1 Ms to study the diffuse X-ray emission in M101. The bulk of the X-ray emission is correlated with the star formation traced by the far-UV (FUV) emission. The global FUV/X-ray correlation is nonlinear (the X-ray surface brightness is roughly proportional to the square root of the FUV surface brightness) and the small-scale correlation is poor, probably due to the delay between the FUV emission and the X-ray production in star-forming regions. The X-ray emission contains only minor contributions from unresolved stars (∼<3%), unresolved X-ray point sources (∼<4%), and individual supernova remnants (∼3%). The global spectrum of the diffuse emission can be reasonably well fitted with a three-component thermal model, but the fitted temperatures are not unique; many distributions of emission measure can produce the same temperatures when observed with the current CCD energy resolution. The spectrum of the diffuse emission depends on the environment; regions with higher X-ray surface brightnesses have relatively stronger hard components, but there is no significant evidence that the temperatures of the emitting components increase with surface brightness.

  2. A CHANDRA OBSERVATION OF SNR 0540 - 697

    International Nuclear Information System (INIS)

    Seward, F. D.; Williams, R. M.; Chu, Y.-H.; Gruendl, R. A.; Dickel, J. R.

    2010-01-01

    This paper describes a Chandra observation of SNR 0540 - 697 within the H II complex N159 in the Large Magellanic Cloud (LMC). Scattering from the nearby bright source LMC X-1, which obscures the western edge of the remnant, has been removed. Larger than previously believed, the 2.'0 x 2.'8 remnant is defined by optical filaments and two lobes of X-ray emission. A band of intervening material absorbs X-rays from the central part of the remnant. The N Lobe of the remnant is relatively bright and well defined, while emission from the S Lobe is much weaker. There is structure within the N Lobe but no clear X-ray emission from an outer shell indicating a shock in the interstellar medium. The X-ray spectrum is thermal with emission lines from Fe, Mg, and Si. The observed temperature and luminosity of the hot gas are 0.6 keV and 6 x 10 35 erg s -1 , respectively. These are consistent with characteristics expected for older remnants. There is also diffuse thermal X-ray emission north of N159 extending into N160, evidence for a larger remnant or bubble.

  3. CIAO: CHANDRA/X-RAY DATA ANALYSIS FOR EVERYONE

    Science.gov (United States)

    McDowell, Jonathan; CIAO Team

    2018-01-01

    Eighteen years after the launch of Chandra, the archive is full of scientifically rich data and new observations continue. Improvements in recent years to the data analysis package CIAO (Chandra Interactive Analysis of Observations) and its extensive accompanying documentation make it easier for astronomers without a specialist background in high energy astrophysics to take advantage of this resource.The CXC supports hundreds of CIAO users around the world at all levels of training from high school and undergraduate students to the most experienced X-ray astronomers. In general, we strive to provide a software system which is easy for beginners, yet powerful for advanced users.Chandra data cover a range of instrument configurations and types of target (pointlike, extended and moving), requiring a flexible data analysis system. In addition to CIAO tools using the familiar FTOOLS/IRAF-style parameter interface, CIAO includes applications such as the Sherpa fitting engine which provide access to the data via Python scripting.In this poster we point prospective (and existing!) users to the high level Python scripts now provided to reprocess Chandra or other X-ray mission data, determine source fluxes and upper limits, and estimate backgrounds; and to the latest documentation including the CIAO Gallery, a new entry point featuring the system's different capabilities.This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  4. 15th IEEE/ACIS International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing

    CERN Document Server

    2015-01-01

    This edited book presents scientific results of 15th IEEE/ACIS International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing (SNPD 2014) held on June 30 – July 2, 2014 in Las Vegas Nevada, USA. The aim of this conference was to bring together scientists, engineers, computer users, and students to share their experiences and exchange new ideas, research results about all aspects (theory, applications and tools) of computer and information science, and to discuss the practical challenges encountered along the way and the solutions adopted to solve them. The conference organizers selected the 13 outstanding papers from those papers accepted for presentation at the conference.

  5. 14th ACIS/IEEE International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing

    CERN Document Server

    Studies in Computational Intelligence : Volume 492

    2013-01-01

    This edited book presents scientific results of the 14th ACIS/IEEE International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing (SNPD 2013), held in Honolulu, Hawaii, USA on July 1-3, 2013. The aim of this conference was to bring together scientists, engineers, computer users, and students to share their experiences and exchange new ideas, research results about all aspects (theory, applications and tools) of computer and information science, and to discuss the practical challenges encountered along the way and the solutions adopted to solve them. The conference organizers selected the 17 outstanding papers from those papers accepted for presentation at the conference.  

  6. Adição de escória de alto forno em argamassas colantes tipo AC-I High oven slag addition in tile adhesive type AC-I

    Directory of Open Access Journals (Sweden)

    J. Rossa Jr.

    2012-12-01

    Full Text Available Neste estudo foi investigado o uso da adição da escória de forno em argamassa colante tipo ACI, em substituição ao cimento de Portland. Os aspectos físicos e químicos (difração de raios X, fluorescência de raios X, microscopia eletrônica de varredura e análise por dispersão de elétrons de três composições de escória de diferentes partes do Brasil foram estudados, usando a escória de menor reatividade. Os resultados indicaram a potencialidade do seu uso, com resistência de aderência à tração similar às amostras de referência e mais altas do que as recomendações normativas.In this study the use of high oven slag addition in tile adhesives, type AC-I, in place of Portland's cement parts of mass was investigated. The physical and chemical aspects (XRD, XRF, SEM and EDS of three compositions of different parts from Brazil slag were studied, using the less reactivity slag. The results indicated the potentiality of use, with similar adherence strain stress to reference samples and higher than the standard recommendation.

  7. Lessons We Learned Designing and Building the Chandra Telescope

    Science.gov (United States)

    Arenberg, Jonathan; Matthews, Gary; Atkinson, C.; Cohen, L.; Golisano, C.; Havey, K.; Hefner, K.; Jones, C.; Kegley, J.; Knollenberg, P.; hide

    2014-01-01

    2014 marks the crystal (15th) anniversary of the launch of the Chandra X-ray Observatory. This paper offers some of the major lessons learned by some of the key members of the Chandra Telescope team. We offer some of the lessons gleaned from our experiences developing, designing, building and testing the telescope and its subsystems, with 15 years of hindsight. Among the topics to be discussed are the early developmental tests, known as VETA-I and VETA-II, requirements derivation, the impact of late requirements and reflection on the conservatism in the design process.

  8. The Data Inspector: Data Visualization for the Chandra Monitoring Project

    Science.gov (United States)

    Petreshock, J. G.; Wolk, S. J.; Cresitello-Dittmar, M.

    Early on in support of the development of the monitoring system for the Chandra X-ray Observatory (CXO) we discovered the need for a very general, very flexible system to visualize data products. We developed the Data Inspector (DI). The DI is a package of procedures designed to create a generalized multi-purpose data analysis and visualization toolkit focused around Chandra requirements. We will discuss the DI package and the functionalities provided within to meet the Monitoring and Trends Analysis project requirements.

  9. Convenient synthesis of magnetically recyclable Fe{sub 3}O{sub 4}@C@CdS photocatalysts by depositing CdS nanocrystals on carbonized ferrocene

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dan [Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Xie, Jianjian [Department of Materials Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Zhang, Yong; Qiao, Ru [Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Li, Sheng [Department of Materials Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Li, Zhengquan, E-mail: zqli@zjnu.edu.cn [Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Department of Materials Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China)

    2015-10-15

    Development of magnetic visible-light-driven photocatalysts is desirable to the practical application of photocatalyts for collection and recycling use. Here we present a facile approach to synthesize Fe{sub 3}O{sub 4}@C@CdS magnetic photocatalysts which can avoid multi-step preparation process. Through one-step solvothermal carbonization of ferrocene, the produced carbon-coated Fe{sub 3}O{sub 4} clusters can serve as both magnetic cores and deposition substrates for in situ generating crystalline CdS nanocrystals on them by rapid microwave irradiation. The prepared Fe{sub 3}O{sub 4}@C@CdS nanoparticles exhibit a uniform core–shell structure and display good photocatalytic activity and recyclability in the degradation of organic dyes. These magnetic photocatalysts may find potential application in wastewater treatment for the future environment remedy. - Highlights: • A rapid strategy is presented to obtain multifunctional core–shell nanostructures. • Magnetic visible-light-driven Fe{sub 3}O{sub 4}@C@CdS nanophotocatalysts are synthesized. • Carbonized ferrocene can provide both magnetic cores and good deposition substrate. • Photocatalytic and recyclable properties of Fe{sub 3}O{sub 4}@C@CdS nanoparticles are explored.

  10. Acharya Prafulla Chandra at the College of Science

    Indian Academy of Sciences (India)

    Further, the Indian. Chemical Society awards the 'Acharya P C Ray Memorial Lecture' award annually to a chemist. Prafulla Chandra died on June 16,. 1944 in his room in the College of Science. The museum is kept open to the public on all working days. Here lived the man who initiated modern chemical research in India.

  11. Romanticism or Reality? An Exploration of Frances Mary Hendry's "Chandra."

    Science.gov (United States)

    Johnson, Jilaine

    This paper singles out a novel written for children about India, "Chandra" (1995) by Frances Mary Hendry, as a powerful and useful novel to present to today's 11 to 14 year old students. The paper contends that the novel allows students to explore and consider different value systems, challenges them to become aware of prejudice and the…

  12. Cosmological constraints from Chandra observations of galaxy clusters.

    Science.gov (United States)

    Allen, Steven W

    2002-09-15

    Chandra observations of rich, relaxed galaxy clusters allow the properties of the X-ray gas and the total gravitating mass to be determined precisely. Here, we present results for a sample of the most X-ray luminous, dynamically relaxed clusters known. We show that the Chandra data and independent gravitational lensing studies provide consistent answers on the mass distributions in the clusters. The mass profiles exhibit a form in good agreement with the predictions from numerical simulations. Combining Chandra results on the X-ray gas mass fractions in the clusters with independent measurements of the Hubble constant and the mean baryonic matter density in the Universe, we obtain a tight constraint on the mean total matter density of the Universe, Omega(m), and an interesting constraint on the cosmological constant, Omega(Lambda). We also describe the 'virial relations' linking the masses, X-ray temperatures and luminosities of galaxy clusters. These relations provide a key step in linking the observed number density and spatial distribution of clusters to the predictions from cosmological models. The Chandra data confirm the presence of a systematic offset of ca. 40% between the normalization of the observed mass-temperature relation and the predictions from standard simulations. This finding leads to a significant revision of the best-fit value of sigma(8) inferred from the observed temperature and luminosity functions of clusters.

  13. Chandra: Ten Years of Amazing Science with a Great Observatory

    Science.gov (United States)

    Weisskopf, Martin C.

    2009-01-01

    We review briefly review the history of the development of the Chandra X-Ray Observatory, highlighting certain details that many attendees of this Conference might not be aware of. We then present a selection of scientific highlights of the first 10 years of this remarkable and unique mission.

  14. Rejoinder Authors' reply to the comments made by Suresh Chandra ...

    Indian Academy of Sciences (India)

    Suresh Chandra has started his comments on the presumption that we have used experimental data on De to evaluate it. This seems to be constructed on the basis of our inclusion of De experimental data in table 1 of our paper. We have not used experimental values of De as input for computations. As mentioned on page ...

  15. Chandra Observations of Tycho's Supernova Remnant U. Hwang , R ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. We present a new Chandra observation of Tycho's supernova remnant with the Advanced CCD Imaging Spectrometer. Multicolor X- ray imaging reveals new details of the outer shock and ejecta. At energies between 4 and 6 keV, the outline of the outer shock is clearly revealed in. X-rays for the first time.

  16. CHANDRA DEEP OBSERVATION OF XDCP J0044.0-2033, A MASSIVE GALAXY CLUSTER AT z > 1.5

    Energy Technology Data Exchange (ETDEWEB)

    Tozzi, P.; Santos, J. S.; Rosati, P. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Jee, M. J. [Department of Physics, University of California, Davis One Shields Avenue, Davis, CA 95616-8677 (United States); Fassbender, R. [INAF-Osservatorio Astronomico di Roma (OAR), via Frascati 33, I-00040 Monte Porzio Catone (Italy); Nastasi, A. [Istitut d' Astrophysique Spatiale, CNRS, Bat. 121, Université Paris-Sud, F-91405 Orsay (France); Forman, W.; Jones, C. [Harvard-Smithsonian Center for Astrophysics 60 Garden Street, Cambridge, MA 02138 (United States); Sartoris, B.; Borgani, S. [Università degli Studi di Trieste, Dipartimento di Fisica, Via A.Valerio, 2 I-34127 Trieste (Italy); Boehringer, H. [Max-Planck-Institut fr extraterrestrische Physik Giessenbachstr.1, D-85748 Garching (Germany); Altieri, B. [European Space Astronomy Centre (ESAC), European Space Agency, Apartado de Correos 78, E-28691 Villanueva de la Canada, Madrid (Spain); Pratt, G. W. [CEA Saclay, Service d' Astrophysique, LOrme des Merisiers, Bat. 709, F-91191 Gif-sur-Yvette Cedex (France); Nonino, M. [INAF-Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, I-34143 Trieste (Italy)

    2015-01-20

    We report the analysis of the Chandra observation of XDCP J0044.0-2033, a massive, distant (z = 1.579) galaxy cluster discovered in the XDCP survey. The total exposure time of 380 ks with Chandra ACIS-S provides the deepest X-ray observation currently achieved on a massive, high-redshift cluster. Extended emission from the intra cluster medium (ICM) is detected at a very high significance level (S/N ∼ 20) on a circular region with a 44'' radius, corresponding to R {sub ext} = 375 kpc at the cluster redshift. We perform an X-ray spectral fit of the ICM emission modeling the spectrum with a single-temperature thermal mekal model. Our analysis provides a global temperature kT=6.7{sub −0.9}{sup +1.3} keV, and a iron abundance Z{sub Fe}=0.41{sub −0.26}{sup +0.29}Z{sub Fe{sub ⊙}} (error bars correspond to 1σ). We fit the background-subtracted surface brightness profile with a single β-model out to 44'', finding a rather flat profile with no hints of a cool core. We derive the deprojected electron density profile and compute the ICM mass within the extraction radius R {sub ext} = 375 kpc to be M {sub ICM}(r < R {sub ext}) = (1.48 ± 0.20) × 10{sup 13} M {sub ☉}. Under the assumption of hydrostatic equilibrium and assuming isothermality within R {sub ext}, the total mass is M{sub 2500}=1.23{sub −0.27}{sup +0.46}×10{sup 14} M{sub ⊙} for R{sub 2500}=240{sub −20}{sup +30} kpc. Extrapolating the profile at radii larger than the extraction radius R {sub ext} we find M{sub 500}=3.2{sub −0.6}{sup +0.9}×10{sup 14} M{sub ⊙} for R{sub 500}=562{sub −37}{sup +50} kpc. This analysis establishes the existence of virialized, massive galaxy clusters at redshift z ∼ 1.6, paving the way to the investigation of the progenitors of the most massive clusters today. Given its mass and the XDCP survey volume, XDCP J0044.0-2033 does not create significant tension with the WMAP-7 ΛCDM cosmology.

  17. 6th IEEE/ACIS International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing

    CERN Document Server

    2016-01-01

    This edited book presents scientific results of the 16th IEEE/ACIS International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing (SNPD 2015) which was held on June 1 – 3, 2015 in Takamatsu, Japan. The aim of this conference was to bring together researchers and scientists, businessmen and entrepreneurs, teachers, engineers, computer users, and students to discuss the numerous fields of computer science and to share their experiences and exchange new ideas and information in a meaningful way. Research results about all aspects (theory, applications and tools) of computer and information science, and to discuss the practical challenges encountered along the way and the solutions adopted to solve them.

  18. 17th IEEE/ACIS International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing

    CERN Document Server

    SNPD 2016

    2016-01-01

    This edited book presents scientific results of the 17th IEEE/ACIS International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing (SNPD 2016) which was held on May 30 - June 1, 2016 in Shanghai, China. The aim of this conference was to bring together researchers and scientists, businessmen and entrepreneurs, teachers, engineers, computer users, and students to discuss the numerous fields of computer science and to share their experiences and exchange new ideas and information in a meaningful way. Research results about all aspects (theory, applications and tools) of computer and information science, and to discuss the practical challenges encountered along the way and the solutions adopted to solve them.

  19. The Chandra X-Ray Observatory: An overview

    Science.gov (United States)

    Weisskopf, M. C.

    The Chandra X-Ray Observatory, one of NASA's Great Observatories, was successfully launched on July 23, 1999 by the Space Shuttle Columbia. After release from Columbia, an Inertial Upper Stage was used to further boost the observatory. After five subsequent firings over 15 days of an internal propulsion system, the Observatory was placed in a highly elliptical orbit. The first x-rays focussed by the telescope were observed on August 12, 1999. Despite an initial surprise that the x-ray telescope was far more efficient for concentrating low-energy protons than had been anticipated, the observatory is performing well and is returning superb scientific data. Operating together with other space observatories, most notably the recently activated XMM-Newton, it is clear that with Chandra we are entering a new era of discovery in high-energy astrophysics.

  20. Highlights and discoveries from the Chandra X-ray Observatory.

    Science.gov (United States)

    Tananbaum, H; Weisskopf, M C; Tucker, W; Wilkes, B; Edmonds, P

    2014-06-01

    Within 40 years of the detection of the first extra-solar x-ray source in 1962, NASA's Chandra X-ray Observatory has achieved an increase in sensitivity of 10 orders of magnitude, comparable to the gain in going from naked-eye observations to the most powerful optical telescopes over the past 400 years. Chandra is unique in its capabilities for producing sub-arcsecond x-ray images with 100-200 eV energy resolution for energies in the range 0.08 black holes; the growth of supermassive black holes and their role in the regulation of star formation and growth of galaxies; impacts of collisions, mergers, and feedback on growth and evolution of groups and clusters of galaxies; and properties of dark matter and dark energy.

  1. Chandra and Swift Observations of Unidentified Fermi-LAT Objects

    Science.gov (United States)

    Donato, Davide; Cheung, T.; Gehrels, N.

    2010-03-01

    In the last year we targeted some of the unidentified Fermi-LAT objects (UFOs) at high Galactic latitude with Chandra and Swift in order to determine the basic properties (positions, fluxes, hardness ratios) of all X-ray sources within the Fermi-LAT localization circles. These satellites enable us to detect the X-ray conterparts with a flux limit that is at least an order of magnitude lower than achieved in extant RASS data and to further follow-up at other wavelengths, with the ultimate goal to reveal the nature of these enigmatic gamma-ray sources. Here we present the results obtained with 5 Chandra pointings of high Galactic latitude UFOs in the Fermi-LAT 3-months bright source list. The association of detected X-ray sources within the improved 11-months Fermi-LAT localization circles with available optical and radio observations is discussed.

  2. Improving the Multi-Wavelength Capability of Chandra Large Programs

    Science.gov (United States)

    Pacucci, Fabio

    2017-09-01

    In order to fully exploit the joint Chandra/JWST/HST ventures to detect faint sources, we urgently need an advanced matching algorithm between optical/NIR and X-ray catalogs/images. This will be of paramount importance in bridging the gap between upcoming optical/NIR facilities (JWST) and later X-ray ones (Athena, Lynx). We propose to develop an advanced and automated tool to improve the identification of Chandra X-ray counterparts detected in deep optical/NIR fields based on T-PHOT, a software widely used in the community. The developed code will include more than 20 years in advancements of X-ray data analysis and will be released to the public. Finally, we will release an updated catalog of X-ray sources in the CANDELS regions: a leap forward in our endeavor of charting the Universe.

  3. The Chandra Source Catalog 2.0: Building The Catalog

    Science.gov (United States)

    Grier, John D.; Plummer, David A.; Allen, Christopher E.; Anderson, Craig S.; Budynkiewicz, Jamie A.; Burke, Douglas; Chen, Judy C.; Civano, Francesca Maria; D'Abrusco, Raffaele; Doe, Stephen M.; Evans, Ian N.; Evans, Janet D.; Fabbiano, Giuseppina; Gibbs, Danny G., II; Glotfelty, Kenny J.; Graessle, Dale E.; Hain, Roger; Hall, Diane M.; Harbo, Peter N.; Houck, John C.; Lauer, Jennifer L.; Laurino, Omar; Lee, Nicholas P.; Martínez-Galarza, Juan Rafael; McCollough, Michael L.; McDowell, Jonathan C.; Miller, Joseph; McLaughlin, Warren; Morgan, Douglas L.; Mossman, Amy E.; Nguyen, Dan T.; Nichols, Joy S.; Nowak, Michael A.; Paxson, Charles; Primini, Francis Anthony; Rots, Arnold H.; Siemiginowska, Aneta; Sundheim, Beth A.; Tibbetts, Michael; Van Stone, David W.; Zografou, Panagoula

    2018-01-01

    To build release 2.0 of the Chandra Source Catalog (CSC2), we require scientific software tools and processing pipelines to evaluate and analyze the data. Additionally, software and hardware infrastructure is needed to coordinate and distribute pipeline execution, manage data i/o, and handle data for Quality Assurance (QA) intervention. We also provide data product staging for archive ingestion.Release 2 utilizes a database driven system used for integration and production. Included are four distinct instances of the Automatic Processing (AP) system (Source Detection, Master Match, Source Properties and Convex Hulls) and a high performance computing (HPC) cluster that is managed to provide efficient catalog processing. In this poster we highlight the internal systems developed to meet the CSC2 challenge.This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  4. Preclinical activity, pharmacodynamic, and pharmacokinetic properties of a selective HDAC6 inhibitor, ACY-1215, in combination with bortezomib in multiple myeloma.

    Science.gov (United States)

    Santo, Loredana; Hideshima, Teru; Kung, Andrew L; Tseng, Jen-Chieh; Tamang, David; Yang, Min; Jarpe, Matthew; van Duzer, John H; Mazitschek, Ralph; Ogier, Walter C; Cirstea, Diana; Rodig, Scott; Eda, Homare; Scullen, Tyler; Canavese, Miriam; Bradner, James; Anderson, Kenneth C; Jones, Simon S; Raje, Noopur

    2012-03-15

    Histone deacetylase (HDAC) enzymatic activity has been linked to the transcription of DNA in cancers including multiple myeloma (MM). Therefore, HDAC inhibitors used alone and in combination are being actively studied as novel therapies in MM. In the present study, we investigated the preclinical activity of ACY-1215, an HDAC6-selective inhibitor, alone and in combination with bortezomib in MM. Low doses of ACY-1215 combined with bortezomib triggered synergistic anti-MM activity, resulting in protracted endoplasmic reticulum stress and apoptosis via activation of caspase-3, caspase-8, and caspase-9 and poly (ADP) ribosome polymerase. In vivo, the anti-MM activity of ACY-1215 in combination with bortezomib was confirmed using 2 different xenograft SCID mouse models: human MM injected subcutaneously (the plasmacytoma model) and luciferase-expressing human MM injected intravenously (the disseminated MM model). Tumor growth was significantly delayed and overall survival was significantly prolonged in animals treated with the combination therapy. Pharmacokinetic data showed peak plasma levels of ACY-1215 at 4 hours after treatment coincident with an increase in acetylated α-tubulin, a marker of HDAC6 inhibition, by immunohistochemistry and Western blot analysis. These studies provide preclinical rationale for acetylated α-tubulin use as a pharmacodynamic biomarker in future clinical trials.

  5. Chandra Observations of Tycho's Supernova Remnant U. Hwang , R ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    runaway thermal instabilities in a white dwarf. It was observed for 50 ks with the superb 0.5 resolution mirror on the Chandra X-ray .... emission that comes from ejecta that have propagated to the forward shock. Such a spectrum, taken from a portion of the west rim of the remnant, is shown in the right panel of Fig. 2. The fitted ...

  6. Deep Chandra observations of HCG 16. II. The development of the intra-group medium in a spiral-rich group

    Energy Technology Data Exchange (ETDEWEB)

    O' Sullivan, E.; Vrtilek, J. M.; David, L. P.; Zezas, A.; Nulsen, P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Giacintucci, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Ponman, T. J.; Raychaudhury, S. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); Mamon, G. A. [Institut d' Astrophysique de Paris (UMR 7095 CNRS and UMPC), 98 bis Bd Arago, F-75014 Paris (France)

    2014-10-01

    We use a combination of deep Chandra X-ray observations and radio continuum imaging to investigate the origin and current state of the intra-group medium (IGM) in the spiral-rich compact group HCG 16. We confirm the presence of a faint (L {sub X,} {sub bolo} = 1.87{sub −0.66}{sup +1.03}×10{sup 41} erg s{sup –1}), low-temperature (0.30{sub −0.05}{sup +0.07} keV) IGM extending throughout the ACIS-S3 field of view, with a ridge linking the four original group members and extending to the southeast, as suggested by previous ROSAT and XMM-Newton observations. This ridge contains 6.6{sub −3.3}{sup +3.9}× 10{sup 9} M {sub ☉} of hot gas and is at least partly coincident with a large-scale H I tidal filament, indicating that the IGM in the inner part of the group is highly multi-phase. We present evidence that the group is not yet virialized, and show that gas has probably been transported from the starburst winds of NGC 838 and NGC 839 into the surrounding IGM. Considering the possible origin of the IGM, we argue that material ejected by galactic winds may have played a significant role, contributing 20%-40% of the observed hot gas in the system.

  7. Deep Chandra Observations of HCG 16. II. The Development of the Intra-group Medium in a Spiral-rich Group

    Science.gov (United States)

    O'Sullivan, E.; Vrtilek, J. M.; David, L. P.; Giacintucci, S.; Zezas, A.; Ponman, T. J.; Mamon, G. A.; Nulsen, P.; Raychaudhury, S.

    2014-10-01

    We use a combination of deep Chandra X-ray observations and radio continuum imaging to investigate the origin and current state of the intra-group medium (IGM) in the spiral-rich compact group HCG 16. We confirm the presence of a faint (L X, bolo = 1.87+1.03-0.66×1041 erg s-1), low-temperature (0.30+0.07-0.05 keV) IGM extending throughout the ACIS-S3 field of view, with a ridge linking the four original group members and extending to the southeast, as suggested by previous ROSAT and XMM-Newton observations. This ridge contains 6.6+3.9-3.3× 109 M ⊙ of hot gas and is at least partly coincident with a large-scale {H} {I} tidal filament, indicating that the IGM in the inner part of the group is highly multi-phase. We present evidence that the group is not yet virialized, and show that gas has probably been transported from the starburst winds of NGC 838 and NGC 839 into the surrounding IGM. Considering the possible origin of the IGM, we argue that material ejected by galactic winds may have played a significant role, contributing 20%-40% of the observed hot gas in the system.

  8. A CHANDRA OBSERVATION OF 3C 288-REHEATING THE COOL CORE OF A 3 keV CLUSTER FROM A NUCLEAR OUTBURST at z = 0.246

    International Nuclear Information System (INIS)

    Lal, D. V.; Kraft, R. P.; Forman, W. R.; Jones, C.; Nulsen, P. E. J.; Evans, D. A.; Lee, J. C.; Hardcastle, M. J.; Croston, J. H.

    2010-01-01

    We present results from a 42 ks Chandra/ACIS-S observation of the transitional FR I/FR II radio galaxy 3C 288 at z = 0.246. We detect ∼3 keV gas extending to a radius of ∼0.5 Mpc with a 0.5-2.0 keV luminosity of 6.6 x 10 43 erg s -1 , implying that 3C 288 lies at the center of a poor cluster. We find multiple surface brightness discontinuities in the gas indicative of either a shock driven by the inflation of the radio lobes or a recent merger event. The temperature across the discontinuities is roughly constant with no signature of a cool core, thus disfavoring either the merger cold front or sloshing scenarios. We argue therefore that the discontinuities are shocks due to the supersonic inflation of the radio lobes. If they are shocks, the energy of the outburst is ∼10 60 erg, or roughly 30% of the thermal energy of the gas within the radius of the shock, assuming that the shocks are part of a front produced by a single outburst. The cooling time of the gas is ∼10 8 yr, so that the energy deposited by the nuclear outburst could have reheated and efficiently disrupted a cool core.

  9. The Chandra X-ray Observatory data processing system

    Science.gov (United States)

    Evans, Ian; Cresitello-Dittmar, Mark; Doe, Stephen; Evans, Janet; Fabbiano, Giuseppina; Germain, Gregg; Glotfelty, Kenny; Plummer, David; Zografou, Panagoula

    2006-06-01

    Raw data from the Chandra X-ray Observatory are processed by a set of standard data processing pipelines to create scientifically useful data products appropriate for further analysis by end users. Fully automated pipelines read the dumped raw telemetry byte stream from the spacecraft and perform the common reductions and calibrations necessary to remove spacecraft and instrumental signatures and convert the data into physically meaningful quantities that can be further analyzed by observers. The resulting data products are subject to automated validation to ensure correct pipeline processing and verify that the spacecraft configuration and scheduling matched the observers request and any constraints. In addition, pipeline processing monitors science and engineering data for anomalous indications and trending, and triggers alerts if appropriate. Data products are ingested and stored in the Chandra Data Archive, where they are made available for downloading by users. In this paper, we describe the architecture of the data processing system, including the scientific algorithms that are applied to the data, and interfaces to other subsystems. We place particular emphasis on the impacts of design choices on system integrity and maintainability. We review areas where algorithmic improvements or changes in instrument characteristics have required significant enhancements, and the mechanisms used to effect these changes while assuring continued scientific integrity and robustness. We discuss major enhancements to the data processing system that are currently being developed to automate production of the Chandra Source Catalog.

  10. The Chandra Deep Protocluster Survey: point-source catalogues for a 400-ks observation of the z = 3.09 protocluster in SSA22

    Science.gov (United States)

    Lehmer, B. D.; Alexander, D. M.; Chapman, S. C.; Smail, Ian; Bauer, F. E.; Brandt, W. N.; Geach, J. E.; Matsuda, Y.; Mullaney, J. R.; Swinbank, A. M.

    2009-11-01

    We present X-ray point-source catalogues for a deep ~400-ks Chandra ACIS-I (Advanced CCD Imaging Spectrometer) exposure of the SSA22 field. The observations are centred on a z = 3.09 protocluster, which is populated by Lyman break galaxies (LBGs), Lyα emitters (LAEs) and extended Lyα-emitting blobs (LABs). The survey reaches ultimate (3 count) sensitivity limits of ~5.7 × 10-17 and ~3.0 × 10-16ergcm-2s-1 for the 0.5-2 and 2-8keV bands, respectively (corresponding to L2-10keV ~5.7 × 1042ergs-1 and L10-30keV ~2.0 × 1043ergs-1 at z = 3.09, respectively, for an assumed photon index of Γ = 1.4). These limits make SSA22 the fourth deepest extragalactic Chandra survey yet conducted, and the only one focused on a known high-redshift structure. In total, we detect 297 X-ray point sources and identify one obvious bright extended X-ray source over a ~330arcmin2 region. In addition to our X-ray catalogues, we provide all available optical spectroscopic redshifts and near-infrared and mid-infrared photometry available for our sources. The basic X-ray and infrared properties of our Chandra sources indicate a variety of source types, although absorbed active galactic nuclei (AGN) appear to dominate. In total, we have identified 12 X-ray sources (either via optical spectroscopic redshifts or LAE selection) at z = 3.06 - 3.12 that are likely to be associated with the SSA22 protocluster. These sources have X-ray and multiwavelength properties that suggest they are powered by AGN with 0.5-8keV luminosities in the range of ~1043-1045ergs-1. We have analysed the AGN fraction of sources in the protocluster as a function of local LAE source density and find suggestive evidence for a correlation between AGN fraction and local LAE source density (at the ~96 per cent confidence level), implying that supermassive black hole growth at z ~ 3 is strongest in the highest density regions.

  11. Chandra Grating Spectroscopy of Three Hot White Dwarfs

    Science.gov (United States)

    Adamczak, J.; Werner, K.; Rauch, T.; Schuh, S.; Drake, J. J.; Kruk, J. W.

    2013-01-01

    High-resolution soft X-ray spectroscopic observations of single hot white dwarfs are scarce. With the Chandra Low-Energy Transmission Grating, we have observed two white dwarfs, one is of spectral type DA (LB1919) and the other is a non-DA of spectral type PG1159 (PG1520+525). The spectra of both stars are analyzed, together with an archival Chandra spectrum of another DA white dwarf (GD246). Aims. The soft X-ray spectra of the two DA white dwarfs are investigated in order to study the effect of gravitational settling and radiative levitation of metals in their photospheres. LB1919 is of interest because it has a significantly lower metallicity than DAs with otherwise similar atmospheric parameters. GD246 is the only white dwarf known that shows identifiable individual iron lines in the soft X-ray range. For the PG1159 star, a precise effective temperature determination is performed in order to confine the position of the blue edge of the GW Vir instability region in the HRD. Methods. The Chandra spectra are analyzed with chemically homogeneous as well as stratified NLTE model atmospheres that assume equilibrium between gravitational settling and radiative acceleration of chemical elements. Archival EUV and UV spectra obtained with EUVE, FUSE, and HST are utilized to support the analysis. Results. No metals could be identified in LB1919. All observations are compatible with a pure hydrogen atmosphere. This is in stark contrast to the vast majority of hot DA white dwarfs that exhibit light and heavy metals and to the stratified models that predict significant metal abundances in the atmosphere. For GD246 we find that neither stratified nor homogeneous models can fit the Chandra spectrum. The Chandra spectrum of PG1520+525 constrains the effective temperature to T(sub eff) = 150 000 +/- 10 000 K. Therefore, this nonpulsating star together with the pulsating prototype of the GWVir class (PG1159-035) defines the location of the blue edge of the GWVir instability region

  12. Chandra Reviews Black Hole Musical: Epic But Off-Key

    Science.gov (United States)

    2006-10-01

    A gigantic sonic boom generated by a supermassive black hole has been found with NASA's Chandra X-ray Observatory, along with evidence for a cacophony of deep sound. This discovery was made by using data from the longest X-ray observation ever of M87, a nearby giant elliptical galaxy. M87 is centrally located in the Virgo cluster of galaxies and is known to harbor one of the Universe's most massive black holes. Scientists detected loops and rings in the hot, X-ray emitting gas that permeates the cluster and surrounds the galaxy. These loops provide evidence for periodic eruptions that occurred near the supermassive black hole, and that generate changes in pressure, or pressure waves, in the cluster gas that manifested themselves as sound. Chandra Low Energy X-ray Images of M87 Chandra Low Energy X-ray Images of M87 "We can tell that many deep and different sounds have been rumbling through this cluster for most of the lifetime of the Universe," said William Forman of the Harvard-Smithsonian Center for Astrophysics (CfA). The outbursts in M87, which happen every few million years, prevent the huge reservoir of gas in the cluster from cooling and forming many new stars. Without these outbursts and resultant heating, M87 would not be the elliptical galaxy it is today. "If this black hole wasn't making all of this noise, M87 could have been a completely different type of galaxy," said team member Paul Nulsen, also of the CfA, "possibly a huge spiral galaxy about 30 times brighter than the Milky Way." Chandra High Energy X-ray Image of M87 Chandra High Energy X-ray Image of M87 The outbursts result when material falls toward the black hole. While most of the matter is swallowed, some of it was violently ejected in jets. These jets are launched from regions close to the black hole (neither light nor sound can escape from the black hole itself) and push into the cluster's gas, generating cavities and sound which then propagate outwards. Chandra's M87 observations also

  13. NASA's Chandra Reveals Origin of Key Cosmic Explosions

    Science.gov (United States)

    2010-02-01

    WASHINGTON -- New findings from NASA's Chandra X-ray Observatory have provided a major advance in understanding a type of supernova critical for studying the dark energy that astronomers think pervades the universe. The results show mergers of two dense stellar remnants are the likely cause of many of the supernovae that have been used to measure the accelerated expansion of the universe. These supernovae, called Type Ia, serve as cosmic mile markers to measure expansion of the universe because they can be seen at large distances, and they follow a reliable pattern of brightness. However, until now, scientists have been unsure what actually causes the explosions. "These are such critical objects in understanding the universe," said Marat Gilfanov of the Max Planck Institute for Astrophysics in Germany and lead author of the study that appears in the Feb. 18 edition of the journal Nature. "It was a major embarrassment that we did not know how they worked. Now we are beginning to understand what lights the fuse of these explosions." Most scientists agree a Type Ia supernova occurs when a white dwarf star -- a collapsed remnant of an elderly star -- exceeds its weight limit, becomes unstable and explodes. Scientists have identified two main possibilities for pushing the white dwarf over the edge: two white dwarfs merging or accretion, a process in which the white dwarf pulls material from a sun-like companion star until it exceeds its weight limit. "Our results suggest the supernovae in the galaxies we studied almost all come from two white dwarfs merging," said co-author Akos Bogdan, also of Max Planck. "This is probably not what many astronomers would expect." The difference between these two scenarios may have implications for how these supernovae can be used as "standard candles" -- objects of a known brightness -- to track vast cosmic distances. Because white dwarfs can come in a range of masses, the merger of two could result in explosions that vary somewhat in

  14. Gemini South Multi-Object Spectrograph (GMOS-S) detector Video boards upgrade: improved performance for the Hamamatsu CCDs.

    Science.gov (United States)

    Gimeno, German; Boucher, Luc; Chiboucas, Kristin; Hibon, Pascale; Lazo, Manuel; Murowinski, Richard; Rippa, Matthew; Rogers, Rolando; Rojas, Roberto; Roth, Katherine; White, John

    2016-01-01

    GMOS-S was upgraded with new Hamamatsu CCDs on June 2014, featuring an improved red sensitivity with respect to the previous detectors and significantly less fringing. Early after the commissioning, an issue was identified when observing in any of the binned readout modes, namely that saturated pixels produced a decrease of counts with respect to the bias level in neighboring pixels. This effect, also known as 'banding', spanned the entire width of the amplifier, and while it did not destroy information, it rendered data reduction very cumbersome. Making matters worse, due to the saturation of a bad column on amplifier number 5 (on CCD2, near the middle of the focal plane), it ended up affecting the entire amplifier for almost all exposures longer than a minute. A team of Gemini instrument scientists and engineers investigated the issue and identified the root cause of the problem as originated in the ARC controller video boards. After significant lab testing, it was verified that a newly available revision of the video boards would solve the problem, though modification of the software was required in order to be compatible with them. This work was performed during the last semester of 2014 and the first semester of 2015. The new video boards were installed and commissioned during August 2015. As of September 1st, the new boards are fully installed and integrated, and the 'banding' effect has been completely eliminated. A short period of time was devoted to the recharacterization of the detector system and the new values for the gains, read noise and full well capacity have been derived. As an added benefit, the full well was increased by ~ 10 percent with respect to the previous value. The GMOS-S new detectors are now operating normally in the Gemini observing queue, and performing at full capacity.

  15. Growth characteristics and imaging properties of the morris hepatoma 3924a in ACI rats: A suitable model for transarterial chemoembolization

    International Nuclear Information System (INIS)

    Truebenbach, Jochen; Graepler, Florian; Pereira, Philippe L; Ruck, Peter; Lauer, Ulrich; Gregor, Michael; Claussen, Claus-D.; Huppert, Peter E.

    2000-01-01

    Purpose: For experimental studies investigating modalities and efficacy of transarterial chemoembolization (TACE) in hepatocellular carcinoma (HCC) an animal model resembling the human situation as closely as possible would be appropriate. Specifically, reproducible tumor growth characteristics with the capability for appropriate in vivo imaging to monitor treatment efficacy are required.Methods: Morris hepatoma 3924A was implanted into the liver of 30 ACI rats. Tumor growth was followed by angiography (n=10), ultrasound (US, n=30), native computed tomography (CT. n=16), and native magnetic resonance imaging (MRU n=30) between day 8 and day 36 after implantation. The radiological morphological characteristics were compared with the macroscopic and microscopic histological findings of the explanted tumors.Results: In all 30 animals a solitary liver tumor was found and macroscopically no signs of metastases, ascites, or peritoneal tumor were visible. On histopathological examination tumor sizes ranged between 27 ± 3 mm 3 (day 8) and 3468 ± 79 mm 3 (day 36). The first signs of tumor necrosis occurred at day 16. US allowed tumor visualization from day 8, MRI from day 8, angiography from day 10, and CT from day 14.Conclusions: The tumor model has the potential to be used for the visualization of tumor growth by MRI and US. The potential for monitoring therapeutic effects of TACE needs to be investigated.

  16. Hemp farming development and socioeconomic position of Bačka: Example of Odžaci

    Directory of Open Access Journals (Sweden)

    Stojanović Vladimir

    2016-01-01

    Full Text Available Hemp is a very important agricultural crop for Bačka region. For centuries, hemp had been grown in this area and it had a crucial importance not only for the agriculture, but for the industry and trade of this region as well. From uncultivated, poorly inhabited and underdeveloped area in 18th century, Bačka made its way to a promising region in which agriculture and industry represent the backbone of the economic development. Significant number of colonial settlements from 18th century and colonization period during rule of Austro-Hungarian empress Maria Theresa recognized growing hemp as their main opportunities to prosper. Later on, in these settlements, the small manufactories for hemp processing were built which eventually had grown into larger factories for hemp fabric production. The town of Odžaci was one of these settlements. From a small colonial settlement, it became one of the important industrial centres in Bačka region.

  17. Chandra X-Ray Observations of the Jovian System

    Science.gov (United States)

    Elsner, R. F.; Waite, J. H.; Crary, F.; Majeed, T.; Gladstone, G. R.; Lewis, W. S.; Ford, P. G.; Howell, R. R.; Johnson, R. E.; Bhardwaj, A.; hide

    2002-01-01

    High-spatial resolution Chandra x-ray observations have demonstrated that most of Jupiter's northern auroral x-rays come from a hot spot located significantly poleward of the latitudes connected to the inner magnetosphere. This hot spot appears fixed in magnetic latitude and longitude and coincides with a region exhibiting anomalous ultraviolet and infrared emissions. The hot spot also exhibited approximately 45 minute quasi-periodic oscillations, a period similar to those reported for high-latitude radio and energetic electron bursts observed by near-Jupiter spacecraft. These results invalidate the idea that jovian auroral x-ray emissions are mainly excited by steady precipitation of energetic heavy ions from the inner magnetosphere. Instead, the x-rays appear to result from currently unexplained processes in the outer magnetosphere that produce highly localized and highly variable emissions over an extremely wide range of wavelengths. The Chandra observations also revealed for the first time x-ray emission (about 0.1 GW) from the Io Plasma Torus, as well as very faint x-ray emission (about 1-2 MW) from the Galilean moons Io, Europa, and possibly Ganymede. The emission from the moons is almost certainly due to Kalpha emission of surface atoms (and possibly impact atoms) excited by the impact of highly energetic protons, oxygen, and sulfur atoms and ions from the Torus. The Torus emission is less well understood at present, although bremsstrahlung from the non-thermal tail of the electron distribution may provide a significant fraction. In any case, further observations, already accepted and in the process of being planned, with Chandra, some with the moderate energy resolution of the CCD camera, together with simultaneous Hubble Space Telescope observations and hopefully ground-based IRTF observations should soon provide greater insight into these various processes.

  18. The Chandra Source Catalog 2.0: Interfaces

    Science.gov (United States)

    D'Abrusco, Raffaele; Zografou, Panagoula; Tibbetts, Michael; Allen, Christopher E.; Anderson, Craig S.; Budynkiewicz, Jamie A.; Burke, Douglas; Chen, Judy C.; Civano, Francesca Maria; Doe, Stephen M.; Evans, Ian N.; Evans, Janet D.; Fabbiano, Giuseppina; Gibbs, Danny G., II; Glotfelty, Kenny J.; Graessle, Dale E.; Grier, John D.; Hain, Roger; Hall, Diane M.; Harbo, Peter N.; Houck, John C.; Lauer, Jennifer L.; Laurino, Omar; Lee, Nicholas P.; Martínez-Galarza, Rafael; McCollough, Michael L.; McDowell, Jonathan C.; Miller, Joseph; McLaughlin, Warren; Morgan, Douglas L.; Mossman, Amy E.; Nguyen, Dan T.; Nichols, Joy S.; Nowak, Michael A.; Paxson, Charles; Plummer, David A.; Primini, Francis Anthony; Rots, Arnold H.; Siemiginowska, Aneta; Sundheim, Beth A.; Van Stone, David W.

    2018-01-01

    Easy-to-use, powerful public interfaces to access the wealth of information contained in any modern, complex astronomical catalog are fundamental to encourage its usage. In this poster,I present the public interfaces of the second Chandra Source Catalog (CSC2). CSC2 is the most comprehensive catalog of X-ray sources detected by Chandra, thanks to the inclusion of Chandra observations public through the end of 2014 and to methodological advancements. CSC2 provides measured properties for a large number of sources that sample the X-ray sky at fainter levels than the previous versions of the CSC, thanks to the stacking of single overlapping observations within 1’ before source detection. Sources from stacks are then crossmatched, if multiple stacks cover the same area of the sky, to create a list of unique, optimal CSC2 sources. The properties of sources detected in each single stack and each single observation are also measured. The layered structure of the CSC2 catalog is mirrored in the organization of the CSC2 database, consisting of three tables containing all properties for the unique stacked sources (“Master Source”), single stack sources (“Stack Source”) and sources in any single observation (“Observation Source”). These tables contain estimates of the position, flags, extent, significances, fluxes, spectral properties and variability (and associated errors) for all classes of sources. The CSC2 also includes source region and full-field data products for all master sources, stack sources and observation sources: images, photon event lists, light curves and spectra.CSCview, the main interface to the CSC2 source properties and data products, is a GUI tool that allows to build queries based on the values of all properties contained in CSC2 tables, query the catalog, inspect the returned table of source properties, browse and download the associated data products. I will also introduce the suite of command-line interfaces to CSC2 that can be used in

  19. Investigating the cores of fossil systems with Chandra

    OpenAIRE

    Bharadwaj, V.; Reiprich, T. H.; Sanders, J. S.; Schellenberger, G.

    2015-01-01

    We investigate the cores of fossil galaxy groups and clusters (`fossil systems') using archival Chandra data for a sample of 17 fossil systems. We determined the cool-core fraction for fossils via three observable diagnostics, the central cooling time, cuspiness, and concentration parameter. We quantified the dynamical state of the fossils by the X-ray peak/brightest cluster galaxy (BCG), and the X-ray peak/emission weighted centre separations. We studied the X-ray emission coincident with th...

  20. Chandra and XMM–Newton Observations of H 2 O Maser Galaxy ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... For H2O megamaser galaxy Mrk 348, Chandra and XMM–Newton data are analysed. The nuclear fitting results of XMM–Newton data suggest the possible existence of a heavily obscured AGN. But the nuclear spectrum extracted from Chandra cannot be well-fitted by the best fitting model for XMM–Newton.

  1. 75 FR 7471 - Chandra Coffee and Rabun Boatworks, Complainants v. Georgia Power Company, Respondent; Notice of...

    Science.gov (United States)

    2010-02-19

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 2354-10] Chandra Coffee and Rabun Boatworks, Complainants v. Georgia Power Company, Respondent; Notice of Complaint February 3, 2010. Take notice that on December 14, 2009, as amended on January 8, 2010, Chandra Coffee and Rabun...

  2. Chandra Data Analysis of H2O Megamaser Galaxy NGC 4258 ...

    Indian Academy of Sciences (India)

    c Indian Academy of Sciences. Chandra Data Analysis of H2O Megamaser Galaxy NGC 4258. Baisheng Liu, Jiangshui Zhang. ∗. & Jin Wang. Center for Astrophysics, Guangzhou University, Guangzhou 510006, China. *e-mail: jszhang@gzhu.edu.cn. Abstract. Chandra observations of NGC 4258 were analyzed to inves-.

  3. Cascade impactor practice for a high dose dry powder inhaler at 90 L/min: NGI versus modified 6-stage and 8-stage ACI.

    Science.gov (United States)

    Kamiya, Akihiko; Sakagami, Masahiro; Byron, Peter R

    2009-03-01

    The compendial methods of particle size distribution (PSD) profile determination for dry powder inhalers (DPIs) were compared between the Next Generation Pharmaceutical Impactor (NGI) and the Andersen Cascade Impactor (ACI). Relenza Rotadisk (zanamivir) and Diskhaler was used as a model DPI and sampled into each impactor via its preseparator (PS), at 90 L/min under various protocols. In the NGI, silicone coating was shown to be indispensable to prevent or minimize particle bounce and reentrainment, and to reduce wall losses to the levels acceptable to the compendia (5%). In contrast, the ACI exceeded this 5% limit, regardless of coating, implying different wall loss mechanisms from the NGI. Particle bounce occurred in both impactors, inaccurately undersizing the PSD profiles for Relenza, unless the collection surfaces were coated or an increased number of doses were employed. Hence, the PSD profile for Relenza following single dose collection in the stage-coated NGI was the most accurate. In contrast, the use of the ACI and its PS for Relenza at 90 L/min suffered from several problems, even though the poorly designed PS still resulted in consistent impactor dose and PSD profiles, compared to those obtained from the NGI and its PS. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

  4. Chandra and ALMA observations of the nuclear activity in two strongly lensed star-forming galaxies

    Science.gov (United States)

    Massardi, M.; Enia, A. F. M.; Negrello, M.; Mancuso, C.; Lapi, A.; Vignali, C.; Gilli, R.; Burkutean, S.; Danese, L.; Zotti, G. De

    2018-02-01

    Aim. According to coevolutionary scenarios, nuclear activity and star formation play relevant roles in the early stages of galaxy formation. We aim at identifying them in high-redshift galaxies by exploiting high-resolution and high-sensitivity X-ray and millimeter-wavelength data to confirm the presence or absence of star formation and nuclear activity and describe their relative roles in shaping the spectral energy distributions and in contributing to the energy budgets of the galaxies. Methods: We present the data, model, and analysis in the X-ray and millimeter (mm) bands for two strongly lensed galaxies, SDP.9 (HATLAS J090740.0-004200) and SDP.11 (HATLAS J091043.1-000322), which we selected in the Herschel-ATLAS catalogs for their excess emission in the mid-IR regime at redshift ≳1.5. This emission suggests nuclear activity in the early stages of galaxy formation. We observed both of them with Chandra ACIS-S in the X-ray regime and analyzed the high-resolution mm data that are available in the ALMA Science Archive for SDP.9. By combining the information available in mm, optical, and X-ray bands, we reconstructed the source morphology. Results: Both targets were detected in the X-ray, which strongly indicates highly obscured nuclear activity. ALMA observations for SDP.9 for the continuum and CO(6-5) spectral line with high resolution (0.02 arcsec corresponding to 65 pc at the distance of the galaxy) allowed us to estimate the lensed galaxy redshift to a better accuracy than pre-ALMA estimates (1.5753 ± 0.0003) and to model the emission of the optical, millimetric, and X-ray band for this galaxy. We demonstrate that the X-ray emission is generated in the nuclear environment, which strongly supports that this object has nuclear activity. On the basis of the X-ray data, we attempt an estimate of the black hole properties in these galaxies. Conclusions: By taking advantage of the lensing magnification, we identify weak nuclear activity associated with high

  5. The puzzling detection of x-rays from Pluto by Chandra

    Science.gov (United States)

    Lisse, C. M.; McNutt, R. L.; Wolk, S. J.; Bagenal, F.; Stern, S. A.; Gladstone, G. R.; Cravens, T. E.; Hill, M. E.; Kollmann, P.; Weaver, H. A.; Strobel, D. F.; Elliott, H. A.; McComas, D. J.; Binzel, R. P.; Snios, B. T.; Bhardwaj, A.; Chutjian, A.; Young, L. A.; Olkin, C. B.; Ennico, K. A.

    2017-05-01

    Using Chandra ACIS-S, we have obtained low-resolution imaging X-ray spectrophotometry of the Pluto system in support of the New Horizons flyby on 14 July 2015. Observations were obtained in a trial ;seed; campaign conducted in one visit on 24 Feb 2014, and a follow-up campaign conducted soon after the New Horizons flyby that consisted of 3 visits spanning 26 Jul to 03 Aug 2015. In a total of 174 ksec of on-target time, in the 0.31 to 0.60 keV passband, we measured 8 total photons in a co-moving 11 × 11 pixel2 box (the 90% flux aperture determined by observations of fixed background sources in the field) measuring ∼121,000 × 121,000 km2 (or ∼100 × 100 RPluto) at Pluto. No photons were detected from 0.60 to 1.0 keV in this box during the same exposures. Allowing for background, we find a net signal of 6.8 counts and a statistical noise level of 1.2 counts, for a detection of Pluto in this passband at > 99.95% confidence. The Pluto photons do not have the spectral shape of the background, are coincident with a 90% flux aperture co-moving with Pluto, and are not confused with any background source, so we consider them as sourced from the Pluto system. The mean 0.31 - 0.60 keV X-ray power from Pluto is 200 +200/-100 MW, in the middle range of X-ray power levels seen for other known Solar System emission sources: auroral precipitation, solar X-ray scattering, and charge exchange (CXE) between solar wind (SW) ions and atmospheric neutrals. We eliminate auroral effects as a source, as Pluto has no known magnetic field and the New Horizons Alice UV spectrometer detected no airglow from Pluto during the flyby. Nano-scale atmospheric haze particles could lead to enhanced resonant scattering of solar X-rays from Pluto, but the energy signature of the detected photons does not match the solar spectrum and estimates of Pluto's scattered X-ray emission are 2 to 3 orders of magnitude below the 3.9 ± 0.7 × 10-5cps found in our observations. Charge-exchange-driven emission

  6. Chandra "Hears" A Black Hole For The First Time

    Science.gov (United States)

    2003-09-01

    NASA's Chandra X-ray Observatory detected sound waves, for the first time, from a super-massive black hole. The "note" is the deepest ever detected from an object in the universe. The tremendous amounts of energy carried by these sound waves may solve a longstanding problem in astrophysics. The black hole resides in the Perseus cluster, located 250 million light years from Earth. In 2002, astronomers obtained a deep Chandra observation that shows ripples in the gas filling the cluster. These ripples are evidence for sound waves that have traveled hundreds of thousands of light years away from the cluster's central black hole. perseus animation Illustration of Ripples in Perseus "We have observed the prodigious amounts of light and heat created by black holes, now we have detected the sound," said Andrew Fabian of the Institute of Astronomy (IoA) in Cambridge, England, and leader of the study. In musical terms, the pitch of the sound generated by the black hole translates into the note of B flat. But, a human would have no chance of hearing this cosmic performance, because the note is 57 octaves lower than middle-C (by comparison a typical piano contains only about seven octaves). At a frequency over a million, billion times deeper than the limits of human hearing, this is the deepest note ever detected from an object in the universe. "The Perseus sound waves are much more than just an interesting form of black hole acoustics," said Steve Allen, also of the IoA and a co-investigator in the research. "These sound waves may be the key in figuring out how galaxy clusters, the largest structures in the universe, grow," Allen said. For years astronomers have tried to understand why there is so much hot gas in galaxy clusters and so little cool gas. Hot gas glowing with X-rays should cool, and the dense central gas should cool the fastest. The pressure in this cool central gas should then fall, causing gas further out to sink in towards the galaxy, forming trillions of

  7. Chandra resolves the T Tauri binary system RW Aur

    International Nuclear Information System (INIS)

    Skinner, Stephen L.; Güdel, Manuel

    2014-01-01

    RW Aur is a multiple T Tauri system consisting of an early-K type primary (A) and a K5 companion (B) at a separation of 1.''4. RW Aur A drives a bipolar optical jet that is well characterized optically. We present results of a sensitive Chandra observation whose primary objective was to search for evidence of soft extended X-ray emission along the jet, as has been seen for a few other nearby T Tauri stars. The binary is clearly resolved by Chandra and both stars are detected as X-ray sources. The X-ray spectra of both stars reveal evidence for cool and hot plasma. Surprisingly, the X-ray luminosity of the less-massive secondary is at least twice that of the primary and is variable. The disparity is attributed to the primary whose X-ray luminosity is at the low end of the range for classical T Tauri stars of similar mass based on established correlations. Deconvolved soft-band images show evidence for slight outward elongation of the source structure of RW Aur A along the blueshifted jet axis inside the central arcsecond. In addition, a faint X-ray emission peak is present on the redshifted axis at an offset of 1.''2 ± 0.''2 from the star. Deprojected jet speeds determined from previous optical studies are too low to explain this faint emission peak as shock-heated jet plasma. Thus, unless flow speeds in the redshifted jet have been underestimated, other mechanisms such as magnetic jet heating may be involved.

  8. THE CHANDRA COSMOS LEGACY SURVEY: OPTICAL/IR IDENTIFICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, S.; Civano, F.; Urry, C. M. [Yale Center for Astronomy and Astrophysics, 260 Whitney Avenue, New Haven, CT 06520 (United States); Elvis, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Salvato, M. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching bei München (Germany); Brusa, M.; Lanzuisi, G.; Vignali, C. [Dipartimento di Fisica e Astronomia, Università di Bologna, viale Berti Pichat 6/2, I-40127 Bologna (Italy); Comastri, A.; Gilli, R.; Zamorani, G.; Cappelluti, N. [INAF—Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Hasinger, G. [Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822 (United States); Miyaji, T. [Instituto de Astronomía sede Ensenada, Universidad Nacional Autónoma de México, Km. 103, Carret. Tijunana-Ensenada, Ensenada, BC (Mexico); Treister, E. [Universidad de Concepción, Departamento de Astronomía, Casilla 160-C, Concepción (Chile); Allevato, V.; Finoguenov, A. [Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-00014 Helsinki (Finland); Cardamone, C. [Department of Science, Wheelock College, Boston, MA 02215 (United States); Griffiths, R. E. [Physics and Astronomy Dept., Natural Sciences Division, University of Hawaii at Hilo, 200 W. Kawili Street, Hilo, HI 96720 (United States); Karim, A. [Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany); and others

    2016-01-20

    We present the catalog of optical and infrared counterparts of the Chandra  COSMOS-Legacy  Survey, a 4.6 Ms Chandra  program on the 2.2 deg{sup 2} of the COSMOS field, combination of 56 new overlapping observations obtained in Cycle 14 with the previous C-COSMOS survey. In this Paper we report the i, K, and 3.6 μm identifications of the 2273 X-ray point sources detected in the new Cycle 14 observations. We use the likelihood ratio technique to derive the association of optical/infrared (IR) counterparts for 97% of the X-ray sources. We also update the information for the 1743 sources detected in C-COSMOS, using new K and 3.6 μm information not available when the C-COSMOS analysis was performed. The final catalog contains 4016 X-ray sources, 97% of which have an optical/IR counterpart and a photometric redshift, while ≃54% of the sources have a spectroscopic redshift. The full catalog, including spectroscopic and photometric redshifts and optical and X-ray properties described here in detail, is available online. We study several X-ray to optical (X/O) properties: with our large statistics we put better constraints on the X/O flux ratio locus, finding a shift toward faint optical magnitudes in both soft and hard X-ray band. We confirm the existence of a correlation between X/O and the the 2–10 keV luminosity for Type 2 sources. We extend to low luminosities the analysis of the correlation between the fraction of obscured AGNs and the hard band luminosity, finding a different behavior between the optically and X-ray classified obscured fraction.

  9. The Chandra Source Catalog 2.0: Data Processing Pipelines

    Science.gov (United States)

    Miller, Joseph; Allen, Christopher E.; Budynkiewicz, Jamie A.; Gibbs, Danny G., II; Paxson, Charles; Chen, Judy C.; Anderson, Craig S.; Burke, Douglas; Civano, Francesca Maria; D'Abrusco, Raffaele; Doe, Stephen M.; Evans, Ian N.; Evans, Janet D.; Fabbiano, Giuseppina; Glotfelty, Kenny J.; Graessle, Dale E.; Grier, John D.; Hain, Roger; Hall, Diane M.; Harbo, Peter N.; Houck, John C.; Lauer, Jennifer L.; Laurino, Omar; Lee, Nicholas P.; Martínez-Galarza, Juan Rafael; McCollough, Michael L.; McDowell, Jonathan C.; McLaughlin, Warren; Morgan, Douglas L.; Mossman, Amy E.; Nguyen, Dan T.; Nichols, Joy S.; Nowak, Michael A.; Plummer, David A.; Primini, Francis Anthony; Rots, Arnold H.; Siemiginowska, Aneta; Sundheim, Beth A.; Tibbetts, Michael; Van Stone, David W.; Zografou, Panagoula

    2018-01-01

    With the construction of the Second Chandra Source Catalog (CSC2.0), came new requirements and new techniques to create a software system that can process 10,000 observations and identify nearly 320,000 point and compact X-ray sources. A new series of processing pipelines have been developed to allow for deeper more complete exploration of the Chanda observations. In CSC1.0 there were 4 general pipelines, whereas in CSC2.0 there are 20 data processing pipelines that have been organized into 3 distinct phases of operation - detection, master matching and source property characterization.With CSC2.0, observations within one arcminute of each other are stacked before searching for sources. The detection phase of processing combines the data, adjusts for shifts in fine astrometry, detects sources, and assesses the likelihood that sources are real. During the master source phase, detections across stacks of observations are analyzed for coverage of the same source to produce a master source. Finally, in the source property phase, each source is characterized with aperture photometry, spectrometry, variability and other properties at theobservation, stack and master levels over several energy bands.We present how these pipelines were constructed and the challenges we faced in how we processed data ranging from virtually no counts to millions of counts, how pipelines were tuned to work optimally on a computational cluster, and how we ensure the data produced was correct through various quality assurance steps.This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  10. Chandra position of IGR J17454-2919 and discovery of a possible NIR counterpart

    DEFF Research Database (Denmark)

    Paizis, A.; Nowak, M.; Chati, S.

    2015-01-01

    On 2014 November 3, we observed the recently discovered INTEGRAL source IGR J17454-2919 (ATels #6530, #6574 and #6602) with Chandra HETGS for 20ks. The J2000.0 Chandra position we obtain is RA: 17 45 27.689 DEC: -29 19 53.83 (90% uncertainty of 0.6") This position (2.4" away from the Swift positi...

  11. CHANDRA HIGH-ENERGY TRANSMISSION GRATING SPECTRUM OF AE AQUARII

    International Nuclear Information System (INIS)

    Mauche, Christopher W.

    2009-01-01

    The nova-like cataclysmic binary AE Aqr, which is currently understood to be a former supersoft X-ray binary and current magnetic propeller, was observed for over two binary orbits (78 ks) in 2005 August with the High-Energy Transmission Grating (HETG) on board the Chandra X-ray Observatory. The long, uninterrupted Chandra observation provides a wealth of details concerning the X-ray emission of AE Aqr, many of which are new and unique to the HETG. First, the X-ray spectrum is that of an optically thin multi-temperature thermal plasma; the X-ray emission lines are broad, with widths that increase with the line energy from σ ∼ 1 eV (510 km s -1 ) for O VIII to σ ∼ 5.5 eV (820 km s -1 ) for Si XIV; the X-ray spectrum is reasonably well fit by a plasma model with a Gaussian emission measure distribution that peaks at log T(K) = 7.16, has a width σ = 0.48, an Fe abundance equal to 0.44 times solar, and other metal (primarily Ne, Mg, and Si) abundances equal to 0.76 times solar; and for a distance d = 100 pc, the total emission measure EM = 8.0 x 10 53 cm -3 and the 0.5-10 keV luminosity L X = 1.1 x 10 31 erg s -1 . Second, based on the f/(i + r) flux ratios of the forbidden (f), intercombination (i), and recombination (r) lines of the Heα triplets of N VI, O VII, and Ne IX measured by Itoh et al. in the XMM-Newton Reflection Grating Spectrometer spectrum and those of O VII, Ne IX, Mg XI, and Si XIII in the Chandra HETG spectrum, either the electron density of the plasma increases with temperature by over three orders of magnitude, from n e ∼ 6 x 10 10 cm -3 for N VI [log T(K) ∼ 6] to n e ∼ 1 x 10 14 cm -3 for Si XIII [log T(K) ∼ 7], and/or the plasma is significantly affected by photoexcitation. Third, the radial velocity of the X-ray emission lines varies on the white dwarf spin phase, with two oscillations per spin cycle and an amplitude K ∼ 160 km s -1 . These results appear to be inconsistent with the recent models of Itoh et al., Ikhsanov, and

  12. Soy isoflavone exposure through all life stages accelerates 17β-estradiol-induced mammary tumor onset and growth, yet reduces tumor burden, in ACI rats.

    Science.gov (United States)

    Möller, Frank Josef; Pemp, Daniela; Soukup, Sebastian T; Wende, Kathleen; Zhang, Xiajie; Zierau, Oliver; Muders, Michael H; Bosland, Maarten C; Kulling, Sabine E; Lehmann, Leane; Vollmer, Günter

    2016-08-01

    There is an ongoing debate whether the intake of soy-derived isoflavones (sISO) mediates beneficial or adverse effects with regard to breast cancer risk. Therefore, we investigated whether nutritional exposure to a sISO-enriched diet from conception until adulthood impacts on 17β-estradiol (E2)-induced carcinogenesis in the rat mammary gland (MG). August-Copenhagen-Irish (ACI) rats were exposed to dietary sISO from conception until postnatal day 285. Silastic tubes containing E2 were used to induce MG tumorigenesis. Body weight, food intake, and tumor growth were recorded weekly. At necropsy, the number, position, size, and weight of each tumor were determined. Plasma samples underwent sISO analysis, and the morphology of MG was analyzed. Tumor incidence and multiplicity were reduced by 20 and 56 %, respectively, in the sISO-exposed rats compared to the control rats. Time-to-tumor onset was shortened from 25 to 20 weeks, and larger tumors developed in the sISO-exposed rats. The histological phenotype of the MG tumors was independent of the sISO diet received, and it included both comedo and cribriform phenotypes. Morphological analyses of the whole-mounted MGs also showed no diet-dependent differences. Lifelong exposure to sISO reduced the overall incidence of MG carcinomas in ACI rats, although the time-to-tumor was significantly shortened.

  13. Chandra X-Ray Observatory Observations of the Jovian System

    Science.gov (United States)

    Elsner, R. F.; Bhardwaj, A.; Gladstone, R.; Waite, J. H.; Ford, P.; Branduari-Raymont, G.

    2005-01-01

    Chandra X-ray Observatory (CXO) and XMM-Newton observations of x-rays from the Jovian system have answered questions that arose from early observations with the Einstein and Rosat X-ray Observatories, but in the process of vastly increasing our knowledge of x-ray emission from Jupiter and its environs they have also raised new questions and point to new opportunities for future studies. We will review recent x-ray results on the Jovian system, from the point of view of the CXO, and discuss various questions that have arisen in the course of our studies. We will discuss prospects for more observations in the immediate future, and how they might address open questions. Finally we will briefly describe ways in which an imaging x-ray spectrometer in the vicinity of the Jovian system could provide a wealth of data and results concerning Jupiter's x-ray auroral and disk emission, elemental abundance measurements for the Galilean moons, and detailed studies of x-ray emission from the Io Plasma Torus.

  14. The Chandra M10l Megasecond: Diffuse Emission

    Science.gov (United States)

    Kuntz, K. D.; Snowden, S. L.

    2009-01-01

    Because MIOl is nearly face-on, it provides an excellent laboratory in which to study the distribution of X-ray emitting gas in a typical late-type spiral galaxy. We obtained a Chandra observation with a cumulative exposure of roughly 1 Ms to study the diffuse X-ray emission in MlOl. The bulk of the X-ray emission is correlated with the star formation traced by the FUV emission. The global FUV/Xray correlation is non-linear (the X-ray surface brightness is roughly proportional to the square root of the FUV surface brightness) and the small-scale correlation is poor, probably due to the delay between the FUV emission and the X-ray production ill star-forming regions. The X-ray emission contains only minor contributions from unresolved stars (approximates less than 3%), unresolved X-ray point sources (approximates less than 4%), and individual supernova remnants (approximates 3%). The global spectrum of the diffuse emission can be reasonably well fitted with a three component thermal model, but the fitted temperatures are not unique; many distributions of emission measure can produce the same temperatures when observed with the current CCD energy resolution. The spectrum of the diffuse emission depends on the environment; regions with higher X-ray surface brightnesses have relatively stronger hard components, but there is no significant evidence that the temperatures of the emitting components increase with surface brightness.

  15. Reviewing ChIPS, The Chandra Imaging and Plotting System

    Science.gov (United States)

    Miller, J.; Burke, D. J.; Evans, I. N.; Evans, J. D.; McLaughlin, W.

    2015-09-01

    The Chandra Imaging and Plotting System (ChIPS) is a 2D plotting system designed to allow users to easily create, manipulate, and produce publication quality visualizations. ChIPS has a simple but very powerful interactive interface that allows users to dynamically modify the contents and layout of their plots quickly and efficiently, with the results of any changes being immediately visible. ChIPS allows users to construct their plots fully interactively, and then save the final plot commands as a Python script. This bypasses the need to iteratively edit and rerun the script when developing the plot. Features such as undo and redo commands allow users to easily step backwards and forwards through previous commands, while the ability so save ChIPS sessions in a platform-independent state file allows the session to be restored at any time, even on another machine. Because ChIPS offers a Python interface, users can analyze their data using the broad array of modules offered in Python, and visualize the information in ChIPS at the same time. In this paper we explore the design decisions behind the development of ChIPS and some of the lessons learned along the way.

  16. LOFAR, VLA, and Chandra Observations of the Toothbrush Galaxy Cluster

    Science.gov (United States)

    van Weeren, R. J.; Brunetti, G.; Brüggen, M.; Andrade-Santos, F.; Ogrean, G. A.; Williams, W. L.; Röttgering, H. J. A.; Dawson, W. A.; Forman, W. R.; de Gasperin, F.; Hardcastle, M. J.; Jones, C.; Miley, G. K.; Rafferty, D. A.; Rudnick, L.; Sabater, J.; Sarazin, C. L.; Shimwell, T. W.; Bonafede, A.; Best, P. N.; Bîrzan, L.; Cassano, R.; Chyży, K. T.; Croston, J. H.; Dijkema, T. J.; Enßlin, T.; Ferrari, C.; Heald, G.; Hoeft, M.; Horellou, C.; Jarvis, M. J.; Kraft, R. P.; Mevius, M.; Intema, H. T.; Murray, S. S.; Orrú, E.; Pizzo, R.; Sridhar, S. S.; Simionescu, A.; Stroe, A.; van der Tol, S.; White, G. J.

    2016-02-01

    We present deep LOFAR observations between 120 and 181 MHz of the “Toothbrush” (RX J0603.3+4214), a cluster that contains one of the brightest radio relic sources known. Our LOFAR observations exploit a new and novel calibration scheme to probe 10 times deeper than any previous study in this relatively unexplored part of the spectrum. The LOFAR observations, when combined with VLA, GMRT, and Chandra X-ray data, provide new information about the nature of cluster merger shocks and their role in re-accelerating relativistic particles. We derive a spectral index of α =-0.8+/- 0.1 at the northern edge of the main radio relic, steepening toward the south to α ≈ -2. The spectral index of the radio halo is remarkably uniform (α =-1.16, with an intrinsic scatter of ≤slant 0.04). The observed radio relic spectral index gives a Mach number of { M }={2.8}-0.3+0.5, assuming diffusive shock acceleration. However, the gas density jump at the northern edge of the large radio relic implies a much weaker shock ({ M }≈ 1.2, with an upper limit of { M }≈ 1.5). The discrepancy between the Mach numbers calculated from the radio and X-rays can be explained if either (I) the relic traces a complex shock surface along the line of sight, or (II) if the radio relic emission is produced by a re-accelerated population of fossil particles from a radio galaxy. Our results highlight the need for additional theoretical work and numerical simulations of particle acceleration and re-acceleration at cluster merger shocks.

  17. ChIPS - Chandra's Interactive, Publication-Ready Plotting Tool

    Science.gov (United States)

    Miller, Joseph; Burke, D.; Evans, I.; Evans, J.; Fruscione, A.; Germain, G.; McDowell, J.; McLaughlin, W.; Milaszewski, R.

    2009-09-01

    The Chandra Interactive Plotting System, ChIPS, is a powerful component of the CIAO data analysis system that enables users to visualize their data and construct high-quality, publication-ready plots interactively. The user can control almost every aspect of the plot layout and the properties of individual plot components such as tick positions or symbol styles. ChIPS offers a rich interactive environment to help users design and fine tune their plots. Key features of ChIPS include the ability to explore alternative presentations of their data by interactively adjusting plot parameters or plot component properties, or correct mistakes via the included undo/redo functionality, without having to redo the visualizations from the beginning. Through a Python or S-Lang interface, ChIPS provides a set of high-level user routines which hides the details of the underlying environment from the new user. At the same time, the scripting environment affords experienced users the ability to manipulate data or extend existing functionality. New to CIAO 4.2, all users will benefit from being able to interactively develop plots and then save the steps to create the final product as a script. This can then be used to recreate the visualization with additional data sets. Also new in CIAO 4.2 is the ability to integrate plot data with basic imaging. Users can combine their images (in world coordinates) with plot elements such as overlay contours, grids, or annotations to produce high-quality publication-ready output in the formats expected by the major journals.

  18. NASA'S Chandra Finds Superfluid in Neutron Star's Core

    Science.gov (United States)

    2011-02-01

    NASA's Chandra X-ray Observatory has discovered the first direct evidence for a superfluid, a bizarre, friction-free state of matter, at the core of a neutron star. Superfluids created in laboratories on Earth exhibit remarkable properties, such as the ability to climb upward and escape airtight containers. The finding has important implications for understanding nuclear interactions in matter at the highest known densities. Neutron stars contain the densest known matter that is directly observable. One teaspoon of neutron star material weighs six billion tons. The pressure in the star's core is so high that most of the charged particles, electrons and protons, merge resulting in a star composed mostly of uncharged particles called neutrons. Two independent research teams studied the supernova remnant Cassiopeia A, or Cas A for short, the remains of a massive star 11,000 light years away that would have appeared to explode about 330 years ago as observed from Earth. Chandra data found a rapid decline in the temperature of the ultra-dense neutron star that remained after the supernova, showing that it had cooled by about four percent over a 10-year period. "This drop in temperature, although it sounds small, was really dramatic and surprising to see," said Dany Page of the National Autonomous University in Mexico, leader of a team with a paper published in the February 25, 2011 issue of the journal Physical Review Letters. "This means that something unusual is happening within this neutron star." Superfluids containing charged particles are also superconductors, meaning they act as perfect electrical conductors and never lose energy. The new results strongly suggest that the remaining protons in the star's core are in a superfluid state and, because they carry a charge, also form a superconductor. "The rapid cooling in Cas A's neutron star, seen with Chandra, is the first direct evidence that the cores of these neutron stars are, in fact, made of superfluid and

  19. Chandra X-ray constraints on the candidate Ca-rich gap transient SN 2016hnk

    Science.gov (United States)

    Sell, P. H.; Arur, K.; Maccarone, T. J.; Kotak, R.; Knigge, C.; Sand, D. J.; Valenti, S.

    2018-03-01

    We present a Chandra observation of SN 2016hnk, a candidate Ca-rich gap transient. This observation was specifically designed to test whether or not this transient was the result of the tidal detonation of a white dwarf by an intermediate-mass black hole. Since we detect no X-ray emission 28 d after the discovery of the transient, as predicted from fall-back accretion, we rule out this model. Our upper limit of ˜10 M⊙ does not allow us to rule out a neutron star or stellar-mass black hole detonator due limits on the sensitivity of Chandra to soft X-rays and unconstrained variables tied to the structure of super-Eddington accretion discs. Together with other Chandra and multiwavelength observations, our analysis strongly argues against the intermediate-mass black hole tidal detonation scenario for Ca-rich gap transients more generally.

  20. THE CHANDRA COSMOS-LEGACY SURVEY: THE z > 3 SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, S.; Civano, F.; Urry, C. M. [Yale Center for Astronomy and Astrophysics, 260 Whitney Avenue, New Haven, CT 06520 (United States); Salvato, M. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching bei München (Germany); Shankar, F. [Department of Physics and Astronomy, University of Southampton, Highfield, SO17 1BJ (United Kingdom); Comastri, A.; Lanzuisi, G.; Vignali, C.; Zamorani, G.; Brusa, M.; Gilli, R. [INAF–Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna (Italy); Elvis, M. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Trakhtenbrot, B.; Schawinski, K. [Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Allevato, V. [Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-00014 Helsinki (Finland); Fiore, F. [INAF–Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monte Porzio Catone (Italy); Griffiths, R. [Physics and Astronomy Department, Natural Sciences Division, University of Hawaii at Hilo, 200 W. Kawili Street, Hilo, HI 96720 (United States); Hasinger, G. [Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822 (United States); Miyaji, T. [Instituto de Astronomía sede Ensenada, Universidad Nacional Autónoma de México, Km. 103, Carret. Tijunana-Ensenada, Ensenada, BC (Mexico); Treister, E. [Universidad de Concepción, Departamento de Astronomía, Casilla 160-C, Concepción (Chile)

    2016-08-20

    We present the largest high-redshift (3 < z < 6.85) sample of X-ray-selected active galactic nuclei (AGNs) on a contiguous field, using sources detected in the Chandra COSMOS-Legacy survey. The sample contains 174 sources, 87 with spectroscopic redshift and the other 87 with photometric redshift (z {sub phot}). In this work, we treat z {sub phot} as a probability-weighted sum of contributions, adding to our sample the contribution of sources with z {sub phot} < 3 but z {sub phot} probability distribution >0 at z > 3. We compute the number counts in the observed 0.5–2 keV band, finding a decline in the number of sources at z > 3 and constraining phenomenological models of the X-ray background. We compute the AGN space density at z > 3 in two different luminosity bins. At higher luminosities (log L (2–10 keV) > 44.1 erg s{sup −1}), the space density declines exponentially, dropping by a factor of ∼20 from z ∼ 3 to z ∼ 6. The observed decline is ∼80% steeper at lower luminosities (43.55 erg s{sup −1} < logL(2–10 keV) < 44.1 erg s{sup −1}) from z ∼ 3 to z ∼ 4.5. We study the space density evolution dividing our sample into optically classified Type 1 and Type 2 AGNs. At log L (2–10 keV) > 44.1 erg s{sup −1}, unobscured and obscured objects may have different evolution with redshift, with the obscured component being three times higher at z ∼ 5. Finally, we compare our space density with predictions of quasar activation merger models, whose calibration is based on optically luminous AGNs. These models significantly overpredict the number of expected AGNs at log L (2–10 keV) > 44.1 erg s{sup −1} with respect to our data.

  1. Chandra Observations of Dying Radio Sources in Galaxy Clusters

    Science.gov (United States)

    Murgia, M.; Markevitch, M.; Govoni, F.; Parma, P.; Fanti, R.; de Ruiter, H. R.; Mack, K.-H.

    2012-01-01

    Context. The dying radio sources represent a very interesting and largely unexplored stage of the active galactic nucleus (AGN) evolution. They are considered to be very rare, and almost all of the few known ones were found in galaxy clusters. However, considering the small number detected so far, it has not been possible to draw any firm conclusions about their X-ray environment. Aims. We present X-ray observations performed with the Chandra satellite of the three galaxy clusters Abell 2276, ZwCl 1829.3+6912, and RX J1852.1+5711, which harbor at their center a dying radio source with an ultra-steep spectrum that we recently discovered. Methods. We analyzed the physical properties of the X-ray emitting gas surrounding these elusive radio sources. We determined the global X-ray properties of the clusters, derived the azimuthally averaged profiles of metal abundance, gas temperature, density, and pressure. Furthermore, we estimated the total mass profiles. Results. The large-scale X-ray emission is regular and spherical, suggesting a relaxed state for these systems. Indeed, we found that the three clusters are also characterized by significant enhancements in the metal abundance and declining temperature profiles toward the central region. For all these reasons, we classified RX J1852.1+5711, Abell 2276, and ZwCl 1829.3+6912 as cool-core galaxy clusters. Conclusions. We calculated the non-thermal pressure of the radio lobes assuming that the radio sources are in the minimum energy condition. For all dying sources we found that this is on average about one to two orders of magnitude lower than that of the external gas, as found for many other radio sources at the center of galaxy groups and clusters. We found marginal evidence for the presence of X-ray surface brightness depressions coincident with the fossil radio lobes of the dying sources in A2276 and ZwCl 1829.3+691. We estimated the outburst age and energy output for these two dying sources. The energy power from

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

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F. [Dipartimento di Fisica, Università degli Studi di Torino, via Pietro Giuria 1, I-10125 Torino (Italy); Harris, D. E.; Paggi, A.; Wilkes, B. J.; Kuraszkiewicz, J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Liuzzo, E.; Orienti, M.; Paladino, R. [Istituto di Radioastronomia, INAF, via Gobetti 101, I-40129, Bologna (Italy); Tremblay, G. R. [Yale Center for Astronomy and Astrophysics, Physics Department, Yale University, P.O. Box 208120, New Haven, CT 06520-8120 (United States); Baum, S. A.; O’Dea, C. P. [University of Manitoba, Dept of Physics and Astronomy, Winnipeg, MB R3T 2N2 (Canada)

    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.

  3. Cross-Reactivity between Schistosoma mansoni Antigens and the Latex Allergen Hev b 7: Putative Implication of Cross-Reactive Carbohydrate Determinants (CCDs.

    Directory of Open Access Journals (Sweden)

    Michael J Doenhoff

    Full Text Available IgG antibodies produced by rabbits immunized against S. mansoni antigens cross-reacted with aqueous soluble constituents of a variety of allergens. The antibody cross-reactivity was largely sensitive to degradation by treatment of the target antigens with sodium meta-periodate, suggesting the cross-reactivity was due to carbohydrate determinants that were common to both the schistosome and the allergens (CCDs. The reaction between the rabbit antibodies and a 43 kDa molecule in a rubber latex extract was analysed further: tandem mass spectrometry identified the latex molecule as allergen Hev b 7. Rabbit anti-schistosome IgG antibodies purified by acid-elution from solid-phase latex Hev b 7 reacted with the S. mansoni egg antigens IPSE/alpha-1 and kappa-5 and cercarial antigens SPO-1 and a fatty acid-binding protein. Moreover, purified anti-S. mansoni egg, latex cross-reactive antibodies reacted with antigenic constituents of some fruits, a result of potential relevance to the latex-fruit syndrome of allergic reactions. We propose that IgG anti-schistosome antibodies that cross-react with allergens may be able to block IgE-induced allergic reactions and thus provide a possible explanation for the hygiene hypothesis.

  4. The CHANDRA X-Ray Observatory: Thermal Design, Verification, and Early Orbit Experience

    Science.gov (United States)

    Boyd, David A.; Freeman, Mark D.; Lynch, Nicolie; Lavois, Anthony R. (Technical Monitor)

    2000-01-01

    The CHANDRA X-ray Observatory (formerly AXAF), one of NASA's "Great Observatories" was launched aboard the Shuttle in July 1999. CHANDRA comprises a grazing-incidence X-ray telescope of unprecedented focal-length, collecting area and angular resolution -- better than two orders of magnitude improvement in imaging performance over any previous soft X-ray (0.1-10 keV) mission. Two focal-plane instruments, one with a 150 K passively-cooled detector, provide celestial X-ray images and spectra. Thermal control of CHANDRA includes active systems for the telescope mirror and environment and the optical bench, and largely passive systems for the focal plans instruments. Performance testing of these thermal control systems required 1-1/2 years at increasing levels of integration, culminating in thermal-balance testing of the fully-configured observatory during the summer of 1998. This paper outlines details of thermal design tradeoffs and methods for both the Observatory and the two focal-plane instruments, the thermal verification philosophy of the Chandra program (what to test and at what level), and summarizes the results of the instrument, optical system and observatory testing.

  5. Chandra and XMM–Newton Observations of H2O Maser Galaxy Mrk ...

    Indian Academy of Sciences (India)

    light (Miller & Goodrich 1990). Falcke et al. (2000) reported the discovery of a very luminous H2O maser in Mrk 348 during a radio flare of AGN. 2. Data reduction and analysis. Mrk348 was observed by Chandra and XMM–Newton on 2010 October 13 (ID: 12809) and 2002 July 18 (ID: 0067540201), respectively. These data ...

  6. Dissecting Photometric Redshift for Active Galactic Nucleus Using XMM- and Chandra-COSMOS Samples

    NARCIS (Netherlands)

    Salvato, M.; Ilbert, O.; Hasinger, G.; Rau, A.; Civano, F.; Zamorani, G.; Brusa, M.; Elvis, M.; Vignali, C.; Aussel, H.; Comastri, A.; Fiore, F.; Le Floc'h, E.; Mainieri, V.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Capak, P.; Caputi, K.; Cappelluti, N.; Carollo, C. M.; Contini, T.; Garilli, B.; Iovino, A.; Fotopoulou, S.; Fruscione, A.; Gilli, R.; Halliday, C.; Kneib, J. -P.; Kakazu, Y.; Kartaltepe, J. S.; Koekemoer, A. M.; Kovac, K.; Ideue, Y.; Ikeda, H.; Impey, C. D.; Le Fevre, O.; Lamareille, F.; Lanzuisi, G.; Le Borgne, J. -F.; Le Brun, V.; Lilly, S.; Maier, C.; Manohar, S.; Masters, D.; McCracken, H.; Messias, H.; Mignoli, M.; Mobasher, B.; Nagao, T.; Pello, R.; Puccetti, S.; Perez-Montero, E.; Renzini, A.; Sargent, M.; Sanders, D. B.; Scodeggio, M.; Scoville, N.; Shopbell, P.; Silvermann, J.; Taniguchi, Y.; Tasca, L.; Tresse, L.; Trump, J. R.; Zucca, E.

    2011-01-01

    In this paper, we release accurate photometric redshifts for 1692 counterparts to Chandra sources in the central square degree of the Cosmic Evolution Survey (COSMOS) field. The availability of a large training set of spectroscopic redshifts that extends to faint magnitudes enabled photometric

  7. Rapport de frais de 2016-2017 pour Chandra Madramootoo | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Rapport de frais de 2016-2017 pour Chandra Madramootoo. Total des frais de déplacement : CAD$10,750.19. Réunion du Conseil des gouverneurs. 20 mars 2017 au 22 mars 2017. CAD$821.31. Réunion du Conseil des gouverneurs. 20 novembre 2016 au 23 novembre 2016. CAD$907.94. Initiation des nouveaux ...

  8. Chandra and XMM–Newton Observations of H 2 O Maser Galaxy ...

    Indian Academy of Sciences (India)

    For H2O megamaser galaxy Mrk 266, its Chandra and XMM–Newton data are analyzed here. It shows existence of two obscured nuclei (separation is ∼ 5''). Our preferred model, the high energy reflected model can fit the hard component of both nuclei spectra well.

  9. A Chandra Survey of Supermassive Black Holes with Dynamical Mass Measurements

    NARCIS (Netherlands)

    Gültekin, K.; Cackett, E.M.; Miller, J.M.; Di Matteo, T.; Markoff, S.; Richstone, D.O.

    2012-01-01

    We present Chandra observations of 12 galaxies that contain supermassive black holes (SMBHs) with dynamical mass measurements. Each galaxy was observed for 30 ks and resulted in a total of 68 point-source detections in the target galaxies including SMBH sources, ultraluminous X-ray sources (ULXs),

  10. Chandra and XMM–Newton Observations of H2O Maser Galaxy Mrk ...

    Indian Academy of Sciences (India)

    2002-11-13

    (separation is ∼ 5 ). Our preferred model, the high energy reflected model can fit the hard component of both nuclei spectra well. Key words. Megamaser—Mrk 266—Chandra—XMM–Newton. 1. Data reduction and analysis. Chandra and XMM–Newton observed Mrk 266 on November 13, 2002 with an expo- sure time of 20 ...

  11. Analytic parameter dependence of Harish-Chandra modules for real reductive Lie groups - a family affair

    NARCIS (Netherlands)

    van der Noort, V.

    2009-01-01

    This thesis is written in the subfield of mathematics known as representation theory of real reductive Lie groups. Let G be a Lie group in the Harish-Chandra class with maximal compact subgroup K and Lie algebra g. Let Omega be a connected complex manifold. By a family of G-representations

  12. Chandra observations of comet 9P/Tempel 1 during the Deep Impact campaign

    NARCIS (Netherlands)

    Lisse, C. M.; Dennerl, K.; Christian, D. J.; Wolk, S. J.; Bodewits, D.; Zurbuchen, T. H.; Hansen, K. C.; Hoekstra, R.; Combi, M.; Fry, C. D.; Dryer, M.; Maekinen, T.; Sun, W.; Jansen, K.C.; Mäkinen, T.

    2007-01-01

    We present results from the Chandra X-ray Observatory's extensive campaign studying Comet 9P/Tempel 1 (T1) in support of NASA's Deep Impact (DI) mission. T1 was observed for similar to 295 ks between 30th June and 24th July 2005, and continuously for similar to 64 ks on July 4th during the impact

  13. TRW Ships NASA's Chandra X-ray Observatory To Kennedy Space Center

    Science.gov (United States)

    1999-04-01

    Two U.S. Air Force C-5 Galaxy transport planes carrying the observatory and its ground support equipment landed at Kennedy's Space Shuttle Landing Facility at 2:40 p.m. EST this afternoon. REDONDO BEACH, CA.--(Business Wire)--Feb. 4, 1999--TRW has shipped NASA's Chandra X-ray Observatory ("Chandra") to the Kennedy Space Center (KSC), in Florida, in preparation for a Space Shuttle launch later this year. The 45-foot-tall, 5-ton science satellite will provide astronomers with new information on supernova remnants, the surroundings of black holes, and other celestial phenomena that produce vast quantities of X-rays. Cradled safely in the cargo hold of a tractor-trailer rig called the Space Cargo Transportation System (SCTS), NASA's newest space telescope was ferried on Feb. 4 from Los Angeles International Airport to KSC aboard an Air Force C-5 Galaxy transporter. The SCTS, an Air Force container, closely resembles the size and shape of the Shuttle cargo bay. Over the next few months, Chandra will undergo final tests at KSC and be mated to a Boeing-provided Inertial Upper Stage for launch aboard Space Shuttle Columbia. A launch date for the Space Shuttle STS-93 mission is expected to be announced later this week. The third in NASA's family of Great Observatories that includes the Hubble Space Telescope and the TRW-built Compton Gamma Ray observatory, Chandra will use the world's most powerful X-ray telescope to allow scientists to "see" and monitor cosmic events that are invisible to conventional optical telescopes. Chandra's X-ray images will yield new insight into celestial phenomena such as the temperature and extent of gas clouds that comprise clusters of galaxies and the superheating of gas and dust particles as they swirl into black holes. A TRW-led team that includes the Eastman Kodak Co., Raytheon Optical Systems Inc., and Ball Aerospace & Technologies Corp. designed and built the Chandra X-ray Observatory for NASA's Marshall Space Flight Center. The

  14. The Cosmic History of Black Hole Accretion from Chandra X-ray Stacking

    Science.gov (United States)

    Treister, Ezequiel; Urry, C.; Schawinski, K.; Lee, N.; Natarajan, P.; Volonteri, M.; Sanders, D. B.

    2012-05-01

    In order to fully understand galaxy formation we need to know when in the cosmic history are black holes growing more intensively, in what type of galaxies this growth is happening and what fraction of these sources are invisible at most wavelengths due to obscuration. We take advantage of the rich multi-wavelength data available in the Chandra Deep Field South (CDF-S), including the 4 Msec Chandra observations (the deepest X-ray data to date), in order to measure the amount of black hole accretion as a function of cosmic history, from z 0 to z 6. We obtain stacked rest-frame X-ray spectra for samples of galaxies binned in terms of their IR luminosity, stellar mass and other galaxy properties. We find that the AGN fraction and their typical luminosities, and thus black hole accretion rates, increase with IR luminosity and stellar mass. The integrated intensity at high energies indicates that a significant fraction of the total black hole growth, 22%, occurs in heavily-obscured systems that are not individually detected in even the deepest X-ray observations. We find evidence for a strong connection between significant black hole growth events and major galaxy mergers from z 0 to z 3, while less spectacular but longer accretion episodes are most likely due to other (stochastic) processes. E.T. and K.S. gratefully acknowledges the support provided by NASA through Chandra Postdoctoral Fellowship Award Numbers PF8-90055 and PF9-00069, respectively issued by the Chandra X-ray Observatory Center. E.T. also thanks support by NASA through Chandra Award SP1-12005X Center of Excellence in Astrophysics and Associated Technologies (PFB 06). C. M. Urry acknowledges support from NSF Grants AST-0407295, AST-0449678, AST-0807570, and Yale University.

  15. Chandra studies of the globular cluster 47 Tucanae: A deeper X-ray source catalogue, five new X-ray counterparts to millisecond radio pulsars, and new constraints to r-mode instability window

    Science.gov (United States)

    Bhattacharya, Souradeep; Heinke, Craig O.; Chugunov, Andrey I.; Freire, Paulo C. C.; Ridolfi, Alessandro; Bogdanov, Slavko

    2017-12-01

    We combined Chandra ACIS observations of the globular cluster 47 Tucanae (47 Tuc) from 2000, 2002 and 2014-2015 to create a deeper X-ray source list, and study some of the faint radio millisecond pulsars (MSPs) present in this cluster. We have detected 370 X-ray sources within the half-mass radius (2.79 arcsec) of the cluster, 81 of which are newly identified, by including new data and using improved source detection techniques. The majority of the newly identified sources are in the crowded core region, indicating cluster membership. We associate five of the new X-ray sources with chromospherically active BY Dra or W UMa variables identified by Albrow et al. We present alternative positions derived from two methods, centroiding and image reconstruction, for faint, crowded sources. We are able to extract X-ray spectra of the recently discovered MSPs 47 Tuc aa, 47 Tuc ab, the newly timed MSP 47 Tuc Z, and the newly resolved MSPs 47 Tuc S and 47 Tuc F. Generally, they are well fitted by blackbody or neutron star atmosphere models, with temperatures, luminosities and emitting radii similar to those of other known MSPs in 47 Tuc, though 47 Tuc aa and 47 Tuc ab reach lower X-ray luminosities. We limit X-ray emission from the full surface of the rapidly spinning (542 Hz) MSP 47 Tuc aa, and use this limit to put an upper bound for amplitude of r-mode oscillations in this pulsar as α < 2.5 × 10-9 and constrain the shape of the r-mode instability window.

  16. Relative Precision of Inhaler Aerodynamic Particle Size Distribution (APSD) Metrics by Full Resolution and Abbreviated Andersen Cascade Impactors (ACIs): Part 2—Investigation of Bias in Extra-Fine Mass Fraction with AIM-HRT Impactor

    OpenAIRE

    Mitchell, Jolyon P.; Nagel, Mark W.; Doyle, Cathy C.; Ali, Rubina S.; Avvakoumova, Valentina I.; Christopher, J. David; Quiroz, Jorge; Strickland, Helen; Tougas, Terrence; Lyapustina, Svetlana

    2010-01-01

    The purpose of this study was to resolve an anomalously high measure of extra-fine particle fraction (EPF) determined by the abbreviated cascade impactor possibly relevant for human respiratory tract (AIM-HRT) in the experiment described in Part 1 of this two-part series, in which the relative precision of abbreviated impactors was evaluated in comparison with a full resolution Andersen eight-stage cascade impactor (ACI). Evidence that the surface coating used to mitigate particle bounce was ...

  17. Observations of the Crab Nebula with the Chandra X-Ray Observatory

    Science.gov (United States)

    Weisskopf, Martin C.

    2012-01-01

    The Crab Nebula and its pulsar has been the subject of a number of detailed observations with the Chandra X-ray Observatory. The superb angular resolution of Chandra s high-resolution telescope has made possible numerous remarkable results. Here we describe a number of specific studies of the Crab that I and my colleagues have undertaken. We discuss the geometry of the system, which indicates that the "inner X-ray ring", typically identified with the termination shock of the pulsar s particle wind, is most likely not in the equatorial plane of the pulsar. Other topics are the northern wisps and their evolution with time; the characterization of features in the jet to the southeast; pulse-phase spectroscopy and possible correlations with the features at other wavelengths, particularly the optical polarization; and a search for correlations of the X-ray flux with the recently-discovered gamma -ray flares.

  18. Role of the Chandra X-Ray Observatory Observations for the Study of Ionized Plasmas

    Science.gov (United States)

    Weisskopf, Martin C.

    2010-01-01

    The Chandra X-Ray Observatory, launched in 1999, is now beginning its 12-th year of operation. Chandra, the X-ray component of NASA s Great Observatory program, continues to operate efficiently, somewhat remarkable considering that the Observatory was designed for three years of operation with a goal of five. The Observatory features X-ray optics with sub-arcsecond angular resolution and a small suite of instruments, including transmission gratings, which allow for high-resolution spectroscopy of point sources. We will detail the capabilities of the Observatory for making such spectroscopic measurements and discuss a number of examples of what has been learned about the astrophysical plasmas capable of producing bright X-ray emission.

  19. Middle Tier Services Accessing the Chandra X-Ray Center Data Archive

    Science.gov (United States)

    Patz, A.; Harbo, P.; Moran, J.; van Stone, D.; Zografou, P.

    The Chandra Data Archive team at the Chandra X-ray Center has developed middle tier services that are used by both our search and retrieval applications to uniformly access our data repository. Accessible through an HTTP URL interface, these services can be called by our J2EE web application (WebChaser) and our Java Swing application (Chaser), as well as any other HTTP client. Programs can call the services to retrieve observation data such as a single FITS file, a proposal abstract or a detailed report of observation parameters. Having a central interface to the archive, shared by client applications, facilitates code reusability and easier maintenance. These middle tier services have been written in Java and packaged into a single J2EE application called the Search and Retrieval (SR) Services. The package consists of a web application front-end and an Enterprise Java Beans back-end. This paper describes the design and use of the SR Services.

  20. Chandra's Cosmos: Dark Matter, Black Holes, and Other Wonders Revealed by NASA's Premier X-ray Observatory

    Science.gov (United States)

    Tucker, Wallace H.

    2017-03-01

    On July 23, 1999, the Chandra X-Ray Observatory, the most powerful X-ray telescope ever built, was launched aboard the space shuttle Columbia. Since then, Chandra has given us a view of the universe that is largely hidden from telescopes sensitive only to visible light. In Chandra's Cosmos, the Smithsonian Astrophysical Observatory's Chandra science spokesperson Wallace H. Tucker uses a series of short, connected stories to describe the telescope's exploration of the hot, high-energy face of the universe. The book is organized in three parts: "The Big," covering the cosmic web, dark energy, dark matter, and massive clusters of galaxies; "The Bad," exploring neutron stars, stellar black holes, and supermassive black holes; and "The Beautiful," discussing stars, exoplanets, and life. Chandra has imaged the spectacular, glowing remains of exploded stars and taken spectra showing the dispersal of their elements. Chandra has observed the region around the supermassive black hole in the center of our Milky Way and traced the separation of dark matter from normal matter in the collision of galaxies, contributing to both dark matter and dark energy studies. Tucker explores the implications of these observations in an entertaining, informative narrative aimed at space buffs and general readers alike.

  1. A Broad Iron Line in the Chandra/HETG Spectrum of 4U 1705-44

    NARCIS (Netherlands)

    di Salvo, T.; Iaria, R.; Méndez, R.M.; Burderi, L.; Robba, N.R.; Stella, L.; van der Klis, M.; Tovmassian, G.; Sion, E.

    2004-01-01

    We present preliminary results from a Chandra 30 ks observation of the atoll source 4U 1705-44. In particular we concentrate on the study of the iron K alpha line, using the HEG spectrometer. The iron K alpha line at ~ 6.6 keV is found to be intrinsically broad ( FWHM ~ 1.7 keV); its width can be

  2. Chandra Observations of the Nuclei of Radio Galaxies: 3C 295 and Hydra A

    Science.gov (United States)

    Harris, D. E.; McNamara, B. R.; David, L. P.; Lavoie, Anthony R. (Technical Monitor)

    2000-01-01

    The angular resolution available with Chandra allows us to isolate the X-ray emission from the nucleus of many radio galaxies and obtain their spectra. As expected from unification schemes, spectra so far obtained can best be interpreted as heavily absorbed power laws. We present the spectral parameters so derived for 3C 295 and Hydra A and compare them to data obtained at other wavelengths.

  3. A HIGH FIDELITY SAMPLE OF COLD FRONT CLUSTERS FROM THE CHANDRA ARCHIVE

    International Nuclear Information System (INIS)

    Owers, Matt S.; Nulsen, Paul E. J.; Markevitch, Maxim; Couch, Warrick J.

    2009-01-01

    This paper presents a sample of 'cold front' clusters selected from the Chandra archive. The clusters are selected based purely on the existence of surface brightness edges in their Chandra images which are modeled as density jumps. A combination of the derived density and temperature jumps across the fronts is used to select nine robust examples of cold front clusters: 1ES0657 - 558, Abell 1201, Abell 1758N, MS1455.0+2232, Abell 2069, Abell 2142, Abell 2163, RXJ1720.1+2638, and Abell 3667. This sample is the subject of an ongoing study aimed at relating cold fronts to cluster merger activity, and understanding how the merging environment affects the cluster constituents. Here, temperature maps are presented along with the Chandra X-ray images. A dichotomy is found in the sample in that there exists a subsample of cold front clusters which are clearly mergers based on their X-ray morphologies, and a second subsample of clusters which harbor cold fronts, but have surprisingly relaxed X-ray morphologies, and minimal evidence for merger activity at other wavelengths. For this second subsample, the existence of a cold front provides the sole evidence for merger activity at X-ray wavelengths. We discuss how cold fronts can provide additional information which may be used to constrain merger histories, and also the possibility of using cold fronts to distinguish major and minor mergers.

  4. X-ray observations of dust obscured galaxies in the Chandra deep field south

    Science.gov (United States)

    Corral, A.; Georgantopoulos, I.; Comastri, A.; Ranalli, P.; Akylas, A.; Salvato, M.; Lanzuisi, G.; Vignali, C.; Koutoulidis, L.

    2016-08-01

    We present the properties of X-ray detected dust obscured galaxies (DOGs) in the Chandra deep field south. In recent years, it has been proposed that a significant percentage of the elusive Compton-thick (CT) active galactic nuclei (AGN) could be hidden among DOGs. This type of galaxy is characterized by a very high infrared (IR) to optical flux ratio (f24 μm/fR > 1000), which in the case of CT AGN could be due to the suppression of AGN emission by absorption and its subsequent re-emission in the IR. The most reliable way of confirming the CT nature of an AGN is by X-ray spectroscopy. In a previous work, we presented the properties of X-ray detected DOGs by making use of the deepest X-ray observations available at that time, the 2Ms observations of the Chandra deep fields, the Chandra deep field north (CDF-N), and the Chandra deep field south (CDF-S). In that work, we only found a moderate percentage (DOGs sample. However, we pointed out that the limited photon statistics for most of the sources in the sample did not allow us to strongly constrain this number. In this paper, we further explore the properties of the sample of DOGs in the CDF-S presented in that work by using not only a deeper 6Ms Chandra survey of the CDF-S, but also by combining these data with the 3Ms XMM-Newton survey of the CDF-S. We also take advantage of the great coverage of the CDF-S region from the UV to the far-IR to fit the spectral energy distributions (SEDs) of our sources. Out of the 14 AGN composing our sample, 9 are highly absorbed (NH > 1023 cm-2), whereas 2 look unabsorbed, and the other 3 are only moderately absorbed. Among the highly absorbed AGN, we find that only three could be considered CT AGN. In only one of these three cases, we detect a strong Fe Kα emission line; the source is already classified as a CT AGN with Chandra data in a previous work. Here we confirm its CT nature by combining Chandra and XMM-Newton data. For the other two CT candidates, the non-detection of

  5. Chandra Phase-resolved Spectroscopy of the High Magnetic Field Pulsar B1509−58

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Chin-Ping; Ng, C.-Y. [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Takata, J. [School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei (China); Shannon, R. M. [International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102 (Australia); Johnston, S., E-mail: cphu@hku.hk, E-mail: ncy@bohr.physics.hku.hk [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Box 76, Epping, NSW 1710 (Australia)

    2017-04-01

    We report on a timing and spectral analysis of the young, high magnetic field rotation-powered pulsar (RPP) B1509−58 using Chandra continuous-clocking mode observation. The pulsar’s X-ray light curve can be fit by the two Gaussian components and the pulsed fraction shows moderate energy dependence over the Chandra band. The pulsed X-ray spectrum is well described by a power law with a photon index 1.16(4), which is harder than the values measured with RXTE /PCA and NuSTAR . This result supports the log-parabolic model for the broadband X-ray spectrum. With the unprecedented angular resolution of Chandra , we clearly identified off-pulse X-ray emission from the pulsar, and its spectrum is best fit by a power law plus blackbody model. The latter component has a temperature of ∼0.14 keV with a bolometric luminosity comparable to the luminosities of other young and high magnetic field RPPs, and it lies between the temperature of magnetars and typical RPPs. In addition, we found that the nonthermal X-ray emission of PSR B1509−58 is significantly softer in the off-pulse phase than in the pulsed phase, with the photon index varying between 1.0 and 1.8 and anticorrelated with the flux. This is similar to the behavior of three other young pulsars. We interpreted it as different contributions of pair-creation processes at different altitudes from the neutron star surface according to the outer-gap model.

  6. Chandra and JVLA Observations of HST Frontier Fields Cluster MACS J0717.5+3745

    Energy Technology Data Exchange (ETDEWEB)

    Van Weeren, R. J.; Jones, C.; Forman, W. R.; Andrade-Santos, F.; Pearce, Connor J. J.; David, L.; Kraft, R. P.; Nulsen, P. E. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ogrean, G. A. [Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305-4060 (United States); Bonafede, A.; Brüggen, M. [Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany); Bulbul, E. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Clarke, T. E. [U.S. Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375 (United States); Churazov, E. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741, Garching (Germany); Dawson, W. A. [Lawrence Livermore National Lab, 7000 East Avenue, Livermore, CA 94550 (United States); Donahue, M. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Goulding, A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Mason, B. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Merten, J. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Mroczkowski, T., E-mail: rvanweeren@cfa.harvard.edu [ESO—European Organization for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2, D-85748 Garching b. München (Germany); and others

    2017-02-01

    To investigate the relationship between thermal and non-thermal components in merger galaxy clusters, we present deep JVLA and Chandra observations of the HST Frontier Fields cluster MACS J0717.5+3745. The Chandra image shows a complex merger event, with at least four components belonging to different merging subclusters. Northwest of the cluster, ∼0.7 Mpc from the center, there is a ram-pressure-stripped core that appears to have traversed the densest parts of the cluster after entering the intracluster medium (ICM) from the direction of a galaxy filament to the southeast. We detect a density discontinuity north-northeast of this core, which we speculate is associated with a cold front. Our radio images reveal new details for the complex radio relic and radio halo in this cluster. In addition, we discover several new filamentary radio sources with sizes of 100–300 kpc. A few of these seem to be connected to the main radio relic, while others are either embedded within the radio halo or projected onto it. A narrow-angled-tailed (NAT) radio galaxy, a cluster member, is located at the center of the radio relic. The steep spectrum tails of this active galactic nucleus lead into the large radio relic where the radio spectrum flattens again. This morphological connection between the NAT radio galaxy and relic provides evidence for re-acceleration (revival) of fossil electrons. The presence of hot ≳20 keV ICM gas detected by Chandra near the relic location provides additional support for this re-acceleration scenario.

  7. Op. No A4495 Columbia, STS-93 Chandra - Breakfast, Suiting, and Walkout

    Science.gov (United States)

    1999-01-01

    The primary objective of the STS-93 mission was to deploy the Advanced X-ray Astrophysical Facility, which had been renamed the Chandra X-ray Observatory in honor of the late Indian-American Nobel Laureate Subrahmanyan Chandrasekhar. The mission was launched at 12:31 on July 23, 1999 onboard the space shuttle Columbia. The mission was led by Commander Eileen Collins. The crew was Pilot Jeff Ashby and Mission Specialists Cady Coleman, Steve Hawley and Michel Tognini from the Centre National d'Etudes Spatiales (CNES). This videotape shows the astronauts after breakfast getting into spacesuits, walking out to board the bus, and boarding the bus prior to launch.

  8. Infrared Faint Radio Sources in the Extended Chandra Deep Field South

    Science.gov (United States)

    Huynh, Minh T.

    2009-01-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey (ATLAS) which have no observable counterpart in the Spitzer Wide-area Infrared Extragalactic Survey (SWIRE). The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6 to 70 micron) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the SED of these objects shows that they are consistent with high redshift AGN (z > 2).

  9. Chandra and the VLT Jointly Investigate the Cosmic X-Ray Background

    Science.gov (United States)

    2001-03-01

    Summary Important scientific advances often happen when complementary investigational techniques are brought together . In the present case, X-ray and optical/infrared observations with some of the world's foremost telescopes have provided the crucial information needed to solve a 40-year old cosmological riddle. Very detailed observations of a small field in the southern sky have recently been carried out, with the space-based NASA Chandra X-Ray Observatory as well as with several ground-based ESO telescopes, including the Very Large Telescope (VLT) at the Paranal Observatory (Chile). Together, they have provided the "deepest" combined view at X-ray and visual/infrared wavelengths ever obtained into the distant Universe. The concerted observational effort has already yielded significant scientific results. This is primarily due to the possibility to 'identify' most of the X-ray emitting objects detected by the Chandra X-ray Observatory on ground-based optical/infrared images and then to determine their nature and distance by means of detailed (spectral) observations with the VLT . In particular, there is now little doubt that the so-called 'X-ray background' , a seemingly diffuse short-wave radiation first detected in 1962, in fact originates in a vast number of powerful black holes residing in active nuclei of distant galaxies . Moreover, the present investigation has permitted to identify and study in some detail a prime example of a hitherto little known type of object, a distant, so-called 'Type II Quasar' , in which the central black hole is deeply embedded in surrounding gas and dust. These achievements are just the beginning of a most fruitful collaboration between "space" and "ground". It is yet another impressive demonstration of the rapid progress of modern astrophysics, due to the recent emergence of a new generation of extremely powerful instruments. PR Photo 09a/01 : Images of a small part of the Chandra Deep Field South , obtained with ESO telescopes

  10. NASA Chandra X-ray Observatory Selected as Editor's Choice in 2000 Discover Magazine Awards for Technological Innovation

    Science.gov (United States)

    2000-06-01

    The Chandra X-ray Observatory, NASA's newest and most powerful X-ray space telescope, has been selected as the winner of the Editor's Choice category of the 2000 Discover Magazine Awards for Technological Innovation. The team of government, industry, university and research institutions that designed, built and deployed Chandra for NASA's Marshall Space Flight Center, Huntsville, Ala, will be formally recognized June 24 at a gala awards celebration at Epcot at the Walt Disney World Resort in Orlando, Fl. Dr. Harvey Tananbaum, director of the Smithsonian Astrophysical Observatory's Chandra X-ray Science Center, Cambridge, Mass., which conducts the Chandra science mission for NASA, will receive the award on behalf of the team. "Chandra has opened a new window for astronomers into the universe of high-energy cosmic events such as pulsars, supernova remnants and black holes," said Tananbaum. "We're now able to create spectacularly detailed images of celestial phenomena whose mere existence we could only hypothesize before." Among Chandra's most significant discoveries to date, he lists the detection of a giant ring around the heart of the Crab Nebula, details of the shock wave created by an exploding star and resolution of the high-energy X-ray "glow" in the universe into millions of specific light sources. "The successful launch, deployment and on-orbit operations of NASA's Chandra X-ray Observatory is a testament to the solid partnership between TRW, NASA and the science community that has been enabling NASA's most important space science missions for the past 40 years," said Timothy W. Hannemann, executive vice president and general manager, TRW Space & Electronics Group. "The extraordinary images that Chandra is delivering daily speaks loudly not only to the quality of the science instruments on board, but also to the engineering talents and dedication to mission success exhibited by every member of NASA's Chandra mission team." Chandra, named in honor of Nobel

  11. IDENTIFYING THE LOCATION IN THE HOST GALAXY OF THE SHORT GRB 111117A WITH THE CHANDRA SUBARCSECOND POSITION

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, T.; Troja, E. [Center for Research and Exploration in Space Science and Technology (CRESST), NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Aoki, K. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Guiriec, S.; Barthelmy, S. D. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Im, M.; Jeon, Y. [Center for the Exploration of the Origin of the Universe (CEOU), Department of Physics and Astronomy, Seoul National University, Seoul, 151-747 (Korea, Republic of); Leloudas, G.; Malesani, D.; De Ugarte Postigo, A.; Andersen, M. I. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Melandri, A.; D' Avanzo, P. [INAF-Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy); Urata, Y. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Xu, D. [Department of Particle Physics and Astronomy, The Weizmann Institute of Science, Rehovot 76100 (Israel); Gorosabel, J.; Sanchez-Ramirez, R. [Instituto de Astrofisica de Andalucia (CSIC), Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Bai, J. [Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming, Yunnan Province, 650011 (China); Briggs, M. S. [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Foley, S. [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); and others

    2013-03-20

    We present our successful Chandra program designed to identify, with subarcsecond accuracy, the X-ray afterglow of the short GRB 111117A, which was discovered by Swift and Fermi. Thanks to our rapid target of opportunity request, Chandra clearly detected the X-ray afterglow, though no optical afterglow was found in deep optical observations. The host galaxy was clearly detected in the optical and near-infrared band, with the best photometric redshift of z=1.31{sub -0.23}{sup +0.46} (90% confidence), making it one of the highest known short gamma-ray burst (GRB) redshifts. Furthermore, we see an offset of 1.0 {+-} 0.2 arcsec, which corresponds to 8.4 {+-} 1.7 kpc, between the host and the afterglow position. We discuss the importance of using Chandra for obtaining subarcsecond X-ray localizations of short GRB afterglows to study GRB environments.

  12. Nustar and Chandra insight into the nature of the 3-40 kev nuclear emission in NGC 253

    DEFF Research Database (Denmark)

    Lehmer, B. D.; Wik, D. R.; Hornschemeier, A. E.

    2013-01-01

    that was also near the dynamical center (θ ≈ 0.4 arcsec); however, this source was offset from the 2012 source position by ≈ 1 arcsec. We show that the probability of the 2003 and 2012 hard X-ray sources being unrelated is ≫99.99% based on the Chandra spatial localizations. Interestingly, the Chandra spectrum...... of the 2003 source (3-8 keV) is shallower in slope than that of the 2012 hard X-ray source. Its proximity to the dynamical center and harder Chandra spectrum indicate that the 2003 source is a better AGN candidate than any of the sources detected in our 2012 campaign; however, we were unable to rule out a ULX...

  13. Shocks and cold fronts in merging and massive galaxy clusters: new detections with Chandra

    Science.gov (United States)

    Botteon, A.; Gastaldello, F.; Brunetti, G.

    2018-03-01

    A number of merging galaxy clusters shows the presence of shocks and cold fronts, i.e. sharp discontinuities in surface brightness and temperature. The observation of these features requires an X-ray telescope with high spatial resolution like Chandra, and allows to study important aspects concerning the physics of the intra-cluster medium (ICM), such as its thermal conduction and viscosity, as well as to provide information on the physical conditions leading to the acceleration of cosmic rays and magnetic field amplification in the cluster environment. In this work we search for new discontinuities in 15 merging and massive clusters observed with Chandra by using different imaging and spectral techniques of X-ray observations. Our analysis led to the discovery of 22 edges: 6 shocks, 8 cold fronts and 8 with uncertain origin. All the 6 shocks detected have {{M}}< 2 derived from density and temperature jumps. This work contributed to increase the number of discontinuities detected in clusters and shows the potential of combining diverse approaches aimed to identify edges in the ICM. A radio follow-up of the shocks discovered in this paper will be useful to study the connection between weak shocks and radio relics.

  14. A Chandra grating observation of the dusty Wolf-Rayet star WR 48a

    International Nuclear Information System (INIS)

    Zhekov, Svetozar A.; Gagné, Marc; Skinner, Stephen L.

    2014-01-01

    We present results of a Chandra High-Energy Transmission Grating (HETG) observation of the carbon-rich Wolf-Rayet (WR) star WR 48a. These are the first high-resolution spectra of this object in X-ray. Blueshifted centroids of the spectral lines of ∼ – 360 km s –1 and line widths of 1000-1500 km s –1 (FWHM) were deduced from the analysis of the line profiles of strong emission lines. The forbidden line of Si XIII is strong and not suppressed, indicating that the rarified 10-30 MK plasma forms far from strong sources of far-ultraviolet emission, most likely in a wind collision zone. Global spectral modeling showed that the X-ray spectrum of WR 48a suffered higher absorption in the 2012 October Chandra observation compared with a previous 2008 January XMM-Newton observation. The emission measure of the hot plasma in WR 48a decreased by a factor ∼3 over the same period of time. The most likely physical picture that emerges from the analysis of the available X-ray data is that of colliding stellar winds in a wide binary system with an elliptical orbit. We propose that the unseen secondary star in the system is another WR star or perhaps a luminous blue variable.

  15. M Stars in the TW Hydra Association: A Chandra Large Program Survey

    Science.gov (United States)

    Punzi, Kristina; Kastner, Joel; Principe, David; Stelzer, Beate; Gorti, Uma; Pascucci, Illaria; Argiroffi, Costanza

    2018-01-01

    We have conducted a Cycle 18 Chandra Large Program survey of very cool members of the $\\sim$ 8 Myr-old TW Hydra Association (TWA) to extend our previous study of the potential connections between M star disks and X-rays (Kastner et al. 2016, AJ, 152, 3) to the extreme low-mass end of the stellar initial mass function. The spectral types of our targets extend down to the M/L borderline. Thus we can further investigate the potential connection between the intense X-ray emission from young, low-mass stars and the lifetimes of their circumstellar planet-forming discs, as well as better constrain the age at which coronal activity declines for stellar masses approaching the H-burning limit of $\\sim$ 0.08 M$_{\\odot}$. We present preliminary results from the Cycle 18 survey, including X-ray detection statistics and measurements of relative X-ray luminosities and coronal (X-ray) temperatures for those TWA stars detected by Chandra. This research is supported by SAO/CXC grant GO7-18002A and NASA Astrophysics Data Analysis program grants NNX12AH37G and NNX16AG13G to RIT.

  16. Chandra Cluster Cosmology Project. II. Samples and X-Ray Data Reduction

    DEFF Research Database (Denmark)

    Vikhlinin, A.; Burenin, R. A.; Ebeling, H.

    2009-01-01

    We discuss the measurements of the galaxy cluster mass functions at z ≈ 0.05 and z ≈ 0.5 using high-quality Chandra observations of samples derived from the ROSAT PSPC All-Sky and 400 deg2 surveys. We provide a full reference for the data analysis procedures, present updated calibration of relati......We discuss the measurements of the galaxy cluster mass functions at z ≈ 0.05 and z ≈ 0.5 using high-quality Chandra observations of samples derived from the ROSAT PSPC All-Sky and 400 deg2 surveys. We provide a full reference for the data analysis procedures, present updated calibration...... of relations between the total cluster mass and its X-ray indicators (TX , M gas, and YX ) based on a subsample of low-z relaxed clusters, and present a first measurement of the evolving LX -M tot relation (with M tot estimated from YX ) obtained from a well defined statistically complete cluster sample...

  17. Chandra's Observations of Jupiter's X-Ray Aurora During Juno Upstream and Apojove Intervals

    Science.gov (United States)

    Jackman, C.M.; Dunn, W.; Kraft, R.; Gladstone, R.; Branduardi-Raymont, G.; Knigge, C.; Altamirano, D.; Elsner, R.

    2017-01-01

    The Chandra space telescope has recently conducted a number of campaigns to observe Jupiter's X-ray aurora. The first set of campaigns took place in summer 2016 while the Juno spacecraft was upstream of the planet sampling the solar wind. The second set of campaigns took place in February, June and August 2017 at times when the Juno spacecraft was at apojove (expected close to the magnetopause). We report on these upstream and apojove campaigns including intensities and periodicities of auroral X-ray emissions. This new era of jovian X-ray astronomy means we have more data than ever before, long observing windows (up to 72 kiloseconds for this Chandra set), and successive observations relatively closely spaced in time. These features combine to allow us to pursue novel methods for examining periodicities in the X-ray emission. Our work will explore significance testing of emerging periodicities, and the search for coherence in X-ray pulsing over weeks and months, seeking to understand the robustness and regularity of previously reported hot spot X-ray emissions. The periods that emerge from our analysis will be compared against those which emerge from radio and UV wavelengths.

  18. The Northern Rims of SNR RCW 86 Chandras Recent Observations and their Implications for Particle Acceleration

    Science.gov (United States)

    Castro, Daniel

    2018-01-01

    The Chandra observations towards the northwest (NW) and northeast (NE) rims of supernova remnant (SNR) RCW 86 reveal great detail about the characteristics of the shocks, particle acceleration and the local environments in these 2 distinct regions. Both the NW and NE of RCW 86 show clear evidence of non-thermal X-ray emission, identified as synchrotron radiation from shock-accelerated electrons with TeV energies, interacting with the compressed, and probably amplified, local magnetic field.Magnetic field amplification (MFA) is broadly believed to result from, and contribute to, cosmic ray acceleration at the shocks of SNRs. However, we still lack a detailed understanding of the particle acceleration mechanism, and with this study we address the connection between the shock properties and ambient medium with MFA. The Chandra observations of RCW 86 allowed us to constrain the magnitude of the post- shock magnetic field in the NE and NW rims by deriving synchrotron filament widths, and also the densities in these regions, using thermal emission co-located with the non-thermal rims. I will discuss our analysis in detail and comment on how MFA appears to be related to certain characteristics of the SNR shock.

  19. Monitoring of the Crab Nebula with Chandra and Other Observatories Including HST

    Science.gov (United States)

    Weisskopf, Martin C.

    2014-01-01

    Subsequent to the detections AGILE and Fermi/LAT of the gamma-ray flares from the Crab Nebula in the fall of 2010, this team has been monitoring the X-Ray emission from the Crab on a regular basis. X-Ray observations have taken place typically once per month when viewing constraints allow and more recently four times per year. There have been notable exceptions, e.g. in April of 2011 and March 2013 when we initiated a set of Chandra Target of opportunity observations in conjunction with bright gamma-ray flares. For much of the time regular HST observations were made in conjunction with the Chandra observations. The aim of this program to further characterize, in depth, the X-Ray and optical variations that take place in the nebula, and by so doing determine the regions which contribute to the harder X-ray variations and, if possible, determine the precise location within the Nebula of the origin of the gamma-ray flares. As part of this project members of the team have developed Singular Value Decomposition techniques to sequences of images in order to more accurately characterize features. The current status of the project will be presented highlighting studies of the inner knot and possible correlations with the flares.

  20. A Chandra grating observation of the dusty Wolf-Rayet star WR 48a

    Energy Technology Data Exchange (ETDEWEB)

    Zhekov, Svetozar A. [Space Research and Technology Institute, Akad. G. Bonchev Str., bl.1, Sofia 1113 (Bulgaria); Gagné, Marc [Department of Geology and Astronomy, West Chester University, West Chester, PA 19383 (United States); Skinner, Stephen L., E-mail: szhekov@space.bas.bg, E-mail: mgagne@wcupa.edu, E-mail: stephen.skinner@colorado.edu [CASA, University of Colorado, Boulder, CO 80309 (United States)

    2014-04-10

    We present results of a Chandra High-Energy Transmission Grating (HETG) observation of the carbon-rich Wolf-Rayet (WR) star WR 48a. These are the first high-resolution spectra of this object in X-ray. Blueshifted centroids of the spectral lines of ∼ – 360 km s{sup –1} and line widths of 1000-1500 km s{sup –1} (FWHM) were deduced from the analysis of the line profiles of strong emission lines. The forbidden line of Si XIII is strong and not suppressed, indicating that the rarified 10-30 MK plasma forms far from strong sources of far-ultraviolet emission, most likely in a wind collision zone. Global spectral modeling showed that the X-ray spectrum of WR 48a suffered higher absorption in the 2012 October Chandra observation compared with a previous 2008 January XMM-Newton observation. The emission measure of the hot plasma in WR 48a decreased by a factor ∼3 over the same period of time. The most likely physical picture that emerges from the analysis of the available X-ray data is that of colliding stellar winds in a wide binary system with an elliptical orbit. We propose that the unseen secondary star in the system is another WR star or perhaps a luminous blue variable.

  1. Deep Chandra observations of the stripped galaxy group falling into Abell 2142

    Science.gov (United States)

    Eckert, D.; Gaspari, M.; Owers, M. S.; Roediger, E.; Molendi, S.; Gastaldello, F.; Paltani, S.; Ettori, S.; Venturi, T.; Rossetti, M.; Rudnick, L.

    2017-09-01

    In the local Universe, the growth of massive galaxy clusters mainly operates through the continuous accretion of group-scale systems. The infalling group in Abell 2142 is the poster child of such an accreting group, and as such, it is an ideal target to study the astrophysical processes induced by structure formation. We present the results of a deep (200 ks) observation of this structure with Chandra that highlights the complexity of this system in exquisite detail. In the core of the group, the spatial resolution of Chandra reveals a leading edge and complex AGN-induced activity. The morphology of the stripped gas tail appears straight in the innermost 250 kpc, suggesting that magnetic draping efficiently shields the gas from its surroundings. However, beyond 300 kpc from the core, the tail flares and the morphology becomes strongly irregular, which could be explained by a breaking of the drape, for example, caused by turbulent motions. The power spectrum of surface-brightness fluctuations is relatively flat (P2D ∝ k-2.3), which indicates that thermal conduction is strongly inhibited even beyond the region where magnetic draping is effective. The amplitude of density fluctuations in the tail is consistent with a mild level of turbulence with a Mach number M3D 0.1 - 0.25. Overall, our results show that the processes leading to the thermalization and mixing of the infalling gas are slow and relatively inefficient.

  2. Chandra Observations of the Deep Impact Encounter with Comet 9P/Tempel 1

    Science.gov (United States)

    Lisse, C. M.; Christian, D. J.; Dennerl, K.; Wolk, S. J.; Bodewits, D.; Combi, M. R.; Hoekstra, R.; Makinen, T.; Schultz, P. H.; Weaver, H. A.

    2005-08-01

    On July 4, 2005 NASA's discovery mission Deep Impact (hereafter DI) will send a 375 kg impactor into the nucleus of comet 9P/Tempel 1 at 10.2 km/s relative velocity. In the x-ray, the DI experiment allows for a controlled test of the charge exchange (CXE) emission mechanism that drives cometary x-ray emission (Lisse et al. 2001, Kharchenko and Dalgarno 2001, Krasnopolsky et al.2002). Previous ROSAT and Chandra observations studied cometary x-ray emission as the solar wind changed but the cometary emission remained constant. Here, at a precise time, a fresh amount of neutral material will be injected into a finite volume of the extended atmosphere, or coma, of the comet. This new material will directly increase the emission measure for the comet, passing from the collisionally thick to the collisionally thin regions of emission over the course of days. The DI experiment also allows for a direct search for prompt x-rays created by hyper-velocity impact processes, such as was seen by ROSAT during the impact of the K-fragment of comet D/Shoemaker-Levy 9 on Jupiter (Waite et al. 1995). We report here on the first results of of the Chandra observations of the Deep Impact encounter.

  3. Anatomy of a Merger: A Deep Chandra Observation of Abell 115

    Science.gov (United States)

    Forman, William R.

    2017-08-01

    A deep Chandra observation of Abell 115 provides a unique probe of the anatomy of cluster mergers. The X-ray image shows two prominent subclusters, A115N (north) and A115S (south) with a projected separation of almost 1 Mpc. The X-ray subclusters each have ram-pressure stripped tails that unambiguously indicate the directions of motion. The central BCG of A115N hosts the radio source 3C28 which shows a pair of jets, almost perpendicular to the direction of the sucluster's motion. The jets terminate in lobes each of which has a "tail" pointing IN the direction of motion of the subcluster. The Chandra analysis provides details of the merger including the velocities of the subclusters both through analysis of the cold front and a weak shock. The motion of A115N through the cluster generates counter-rotating vortices in the subcluster gas that form the two radio tails. Hydrodynamic modeling yields circulation velocities within the A115N sub cluster. Thus, the radio emitting plasma acts as a dye tracing the motions of the X-ray emitting plasma. A115S shows two "cores", one coincident with the BCG and a second appears as a ram pressure stripped tail.

  4. A Chandra Study of Supernova Remnants in the Large and Small Magellanic Clouds

    Science.gov (United States)

    Schenck, Andrew Corey

    2017-08-01

    In the first part of this thesis we measure the interstellar abundances for the elements O, Ne, Mg, Si, and Fe in the Large Magellanic Cloud (LMC), based on the observational data of sixteen supernova remnants (SNRs) in the LMC as available in the public archive of the Chandra X-ray Observatory (Chandra). We find lower abundances than previous measurements based on a similar method using data obtained with the Advanced Satellite for Astrophysics and Cosmology (ASCA). We discuss the origins of the discrepancy between our Chandra and the previous ASCA measurements. We conclude that our measurements are generally more reliable than the ASCA results thanks to the high-resolution imaging spectroscopy with our Chandra data, although there remain some systematic uncertainties due to the use of different spectral modelings between the previous work and ours. We also discuss our results in comparison with the LMC abundance measurements based on optical observations of stars. The second part of this thesis is a detailed study of a core-collapse SNR B0049-73.6 in the Small Magellanic Cloud (SMC). Based on our deep Chandra observation, we detect metal-rich ejecta features extending out to the outermost boundary of B0049-73.6, which were not seen in the previous data. We find that the central nebula is dominated by emission from reverse-shocked ejecta material enriched in O, Ne, Mg, and Si. O-rich ejecta distribution is relatively smooth throughout the central nebula. In contrast the Si-rich material is highly structured. These results suggest that B0049-73.6 was produced by an asymmetric core-collapse explosion of a massive star. The estimated abundance ratios among these ejecta elements are in plausible agreement with the nucleosynthesis products from the explosion of a 13-15M. progenitor. We reveal that the central ring-like (in projection) ejecta nebula extends to ˜9 pc from the SNR center. This suggests that the contact discontinuity (CD) may be located at a further

  5. Relative precision of inhaler aerodynamic particle size distribution (APSD) metrics by full resolution and abbreviated andersen cascade impactors (ACIs): part 2--investigation of bias in extra-fine mass fraction with AIM-HRT impactor.

    Science.gov (United States)

    Mitchell, Jolyon P; Nagel, Mark W; Doyle, Cathy C; Ali, Rubina S; Avvakoumova, Valentina I; Christopher, J David; Quiroz, Jorge; Strickland, Helen; Tougas, Terrence; Lyapustina, Svetlana

    2010-09-01

    The purpose of this study was to resolve an anomalously high measure of extra-fine particle fraction (EPF) determined by the abbreviated cascade impactor possibly relevant for human respiratory tract (AIM-HRT) in the experiment described in Part 1 of this two-part series, in which the relative precision of abbreviated impactors was evaluated in comparison with a full resolution Andersen eight-stage cascade impactor (ACI). Evidence that the surface coating used to mitigate particle bounce was laterally displaced by the flow emerging from the jets of the lower stage was apparent upon microscopic examination of the associated collection plate of the AIM-HRT impactor whose cut point size defines EPF. A filter soaked in surfactant was floated on top of this collection plate, and further measurements were made using the same pressurized metered-dose inhaler-based formulation and following the same procedure as in Part 1. Measures of EPF, fine particle, and coarse particle fractions were comparable with those obtained with the ACI, indicating that the cause of the bias had been identified and removed. When working with abbreviated impactors, this precaution is advised whenever there is evidence that surface coating displacement has occurred, a task that can be readily accomplished by microscopic inspection of all collection plates after allowing the impactor to sample ambient air for a few minutes.

  6. LIGO/Virgo GW170817: Chandra X-ray Emission Continues to Rise 156 Days Post-Merger

    Science.gov (United States)

    Haggard, Daryl; Nynka, Melania; Ruan, John J.; Evans, Phil; Kalogera, Vicky

    2018-01-01

    We have obtained new X-ray observations of GW170817 via Chandra Director's Discretionary Time (PI: Wilkes, Program Number 19408607). The X-ray counterpart to GW170817/GRB170817A/SSS17a continues to be detected and the X-ray emission continues to brighten approximately 156 days after the neutron star merger.

  7. VizieR Online Data Catalog: Cool-core clusters with Chandra obs. (Andrade-Santos+, 2017)

    Science.gov (United States)

    Andrade-Santos, F.; Jones, C.; Forman, W. R.; Lovisari, L.; Vikhlinin, A.; van Weeren, R. J.; Murray, S. S.; Arnaud, M.; Pratt, G. W.; Democles, J.; Kraft, R.; Mazzotta, P.; Bohringer, H.; Chon, G.; Giacintucci, S.; Clarke, T. E.; Borgani, S.; David, L.; Douspis, M.; Pointecouteau, E.; Dahle, H.; Brown, S.; Aghanim, N.; Rasia, E.

    2018-02-01

    The main goal of this work is to compare the fraction of cool-core (CC) clusters in X-ray-selected and SZ-selected samples. The first catalog of 189 SZ clusters detected by the Planck mission was released in early 2011 (Planck Collaboration 2011, VIII/88/esz). A Chandra XVP (X-ray Visionary Program--PI: Jones) and HRC Guaranteed Time Observations (PI: Murray) combined to form the Chandra-Planck Legacy Program for Massive Clusters of Galaxies. For each of the 164 ESZ Planck clusters at z<=0.35, we obtained Chandra exposures sufficient to collect at least 10000 source counts. The X-ray sample used here is an extension of the Voevodkin & Vikhlinin (2004ApJ...601..610V) sample. This sample contains 100 clusters and has an effective redshift depth of z<0.3. All have Chandra observations. Of the 100 X-ray-selected clusters, 49 are also in the ESZ sample, and 47 are in the HIFLUGCS (Reiprich & Boehringer 2002ApJ...567..716R) catalog. (2 data files).

  8. A Broad Iron Line in the Chandra High Energy Transmission Grating Spectrum of 4U 1705-44

    NARCIS (Netherlands)

    di Salvo, T.; Iaria, R.; Méndez, R.M.; Burderi, L.; Lavagetto, G.; Robba, N.R.; Stella, L.; van der Klis, M.

    2005-01-01

    We present the results of a Chandra 30 ks observation of the low-mass X-ray binary and atoll source 4U 1705-44. Here we concentrate on the study of discrete features in the energy spectrum at energies below ~3 keV, as well as on the iron Kalpha line, using the High Energy Transmission Grating

  9. Nustar and Chandra Insight into the Nature of the 3-40 Kev Nuclear Emission in Ngc 253

    Science.gov (United States)

    Lehmer, Bret D.; Wik, Daniel R.; Hornschemeier, Ann E.; Ptak, Andrew; Antoniu, V.; Argo, M.K.; Bechtol, K.; Boggs, S.; Christensen, F.E.; Craig, W.W.; hide

    2013-01-01

    We present results from three nearly simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR) and Chandra monitoring observations between 2012 September 2 and 2012 November 16 of the local star-forming galaxy NGC 253. The 3-40 kiloelectron volt intensity of the inner approximately 20 arcsec (approximately 400 parsec) nuclear region, as measured by NuSTAR, varied by a factor of approximately 2 across the three monitoring observations. The Chandra data reveal that the nuclear region contains three bright X-ray sources, including a luminous (L (sub 2-10 kiloelectron volt) approximately few × 10 (exp 39) erg per s) point source located approximately 1 arcsec from the dynamical center of the galaxy (within the sigma 3 positional uncertainty of the dynamical center); this source drives the overall variability of the nuclear region at energies greater than or approximately equal to 3 kiloelectron volts. We make use of the variability to measure the spectra of this single hard X-ray source when it was in bright states. The spectra are well described by an absorbed (power-law model spectral fit value, N(sub H), approximately equal to 1.6 x 10 (exp 23) per square centimeter) broken power-law model with spectral slopes and break energies that are typical of ultraluminous X-ray sources (ULXs), but not active galactic nuclei (AGNs). A previous Chandra observation in 2003 showed a hard X-ray point source of similar luminosity to the 2012 source that was also near the dynamical center (Phi is approximately equal to 0.4 arcsec); however, this source was offset from the 2012 source position by approximately 1 arcsec. We show that the probability of the 2003 and 2012 hard X-ray sources being unrelated is much greater than 99.99% based on the Chandra spatial localizations. Interestingly, the Chandra spectrum of the 2003 source (3-8 kiloelectron volts) is shallower in slope than that of the 2012 hard X-ray source. Its proximity to the dynamical center and harder Chandra spectrum

  10. THE CHANDRA DEEP FIELD-SOUTH SURVEY: 4 Ms SOURCE CATALOGS

    International Nuclear Information System (INIS)

    Xue, Y. Q.; Luo, B.; Brandt, W. N.; Broos, P. S.; Schneider, D. P.; Bauer, F. E.; Lehmer, B. D.; Alexander, D. M.; Brusa, M.; Comastri, A.; Gilli, R.; Fabian, A. C.; Hasinger, G.; Hornschemeier, A. E.; Koekemoer, A.; Liu, T.; Mainieri, V.; Rosati, P.; Paolillo, M.; Rafferty, D. A.

    2011-01-01

    We present source catalogs for the 4 Ms Chandra Deep Field-South (CDF-S), which is the deepest Chandra survey to date and covers an area of 464.5 arcmin 2 . We provide a main Chandra source catalog, which contains 740 X-ray sources that are detected with WAVDETECT at a false-positive probability threshold of 10 -5 in at least one of three X-ray bands (0.5-8 keV, full band; 0.5-2 keV, soft band; and 2-8 keV, hard band) and also satisfy a binomial-probability source-selection criterion of P -5 , satisfy the condition of 0.004 75% of the main-catalog sources are active galactic nuclei (AGNs); of the 300 new main-catalog sources, about 35% are likely normal and starburst galaxies, reflecting the rise of normal and starburst galaxies at the very faint flux levels uniquely accessible to the 4 Ms CDF-S. Near the center of the 4 Ms CDF-S (i.e., within an off-axis angle of 3'), the observed AGN and galaxy source densities have reached 9800 +1300 -1100 deg -2 and 6900 +1100 -900 deg -2 , respectively. Simulations show that our main catalog is highly reliable and is reasonably complete. The mean backgrounds (corrected for vignetting and exposure-time variations) are 0.063 and 0.178 counts Ms -1 pixel -1 (for a pixel size of 0.''492) for the soft and hard bands, respectively; the majority of the pixels have zero background counts. The 4 Ms CDF-S reaches on-axis flux limits of ∼3.2 x 10 -17 , 9.1 x 10 -18 , and 5.5 x 10 -17 erg cm -2 s -1 for the full, soft, and hard bands, respectively. An increase in the CDF-S exposure time by a factor of ∼2-2.5 would provide further significant gains and probe key unexplored discovery space.

  11. NASA Managers Set July 20 As Launch Date for Chandra Telescope

    Science.gov (United States)

    1999-07-01

    NASA managers set Tuesday, July 20, 1999, as the official launch date for NASA's second Space Shuttle Mission of the year that will mark the launch of the first female Shuttle Commander and the Chandra X-Ray Observatory. Columbia is scheduled to liftoff from Launch Pad 39-B at the Kennedy Space Center on July 20 at the opening of a 46-minute launch window at 12:36 a.m. EDT. Columbia's planned five-day mission is scheduled to end with a night landing at the Kennedy Space Center just after 11:30 p.m. EDT on July 24. Following its deployment from the Shuttle, Chandra will join the Hubble Space Telescope and the Compton Gamma Ray Observatory as the next in NASA's series of "Great Observatories." Chandra will spend at least five years in a highly elliptical orbit which will carry it one-third of the way to the moon to observe invisible and often violent realms of the cosmos containing some of the most intriguing mysteries in astronomy ranging from comets in our solar system to quasars at the edge of the universe. Columbia's 26th flight is led by Air Force Col. Eileen Collins, who will command a Space Shuttle mission following two previous flights as a pilot. The STS-93 Pilot is Navy Captain Jeff Ashby who will be making his first flight into space. The three mission specialists for the flight are: Air Force Lt. Col. Catherine "Cady" Coleman, who will be making her second flight into space; Steven A. Hawley, Ph.D, making his fifth flight; and French Air Force Col. Michel Tognini of the French Space Agency (CNES), who is making his first Space Shuttle flight and second trip into space after spending two weeks on the Mir Space Station as a visiting cosmonaut in 1992. NASA press releases and other information are available automatically by sending an Internet electronic mail message to domo@hq.nasa.gov. In the body of the message (not the subject line) users should type the words "subscribe press-release" (no quotes). The system will reply with a confirmation via E-mail of

  12. VLBA AND CHANDRA OBSERVATIONS OF JETS IN FRI RADIO GALAXIES: CONSTRAINTS ON JET EVOLUTION

    International Nuclear Information System (INIS)

    Kharb, P.; O'Dea, C. P.; Tilak, A.; Baum, S. A.; Haynes, E.; Noel-Storr, J.; Fallon, C.; Christiansen, K.

    2012-01-01

    We present here the results from new Very Long Baseline Array (VLBA) observations at 1.6 and 5 GHz of 19 galaxies of a complete sample of 21 Uppasala General Catalog (UGC) Fanaroff-Riley type I (FRI) radio galaxies. New Chandra data of two sources, viz., UGC 00408 and UGC 08433, are combined with the Chandra archival data of 13 sources. The 5 GHz observations of 10 'core-jet' sources are polarization-sensitive, while the 1.6 GHz observations constitute second-epoch total intensity observations of nine 'core-only' sources. Polarized emission is detected in the jets of seven sources at 5 GHz, but the cores are essentially unpolarized, except in M87. Polarization is detected at the jet edges in several sources, and the inferred magnetic field is primarily aligned with the jet direction. This could be indicative of magnetic field 'shearing' due to jet-medium interaction, or the presence of helical magnetic fields. The jet peak intensity I ν falls with distance d from the core, following the relation, I ν ∝d a , where a is typically ∼ – 1.5. Assuming that adiabatic expansion losses are primarily responsible for the jet intensity 'dimming,' two limiting cases are considered: (1) the jet has a constant speed on parsec scales and is expanding gradually such that the jet radius r∝d 0 .4 ; this expansion is, however, unobservable in the laterally unresolved jets at 5 GHz, and (2) the jet is cylindrical and is accelerating on parsec scales. Accelerating parsec-scale jets are consistent with the phenomenon of 'magnetic driving' in Poynting-flux-dominated jets. While slow jet expansion as predicted by case (1) is indeed observed in a few sources from the literature that are resolved laterally, on scales of tens or hundreds of parsecs, case (2) cannot be ruled out in the present data, provided the jets become conical on scales larger than those probed by VLBA. Chandra observations of 15 UGC FRIs detect X-ray jets in 9 of them. The high frequency of occurrence of X

  13. The mystery of the "Kite" radio source in Abell 2626: Insights from new Chandra observations

    Science.gov (United States)

    Ignesti, A.; Gitti, M.; Brunetti, G.; O'Sullivan, E.; Sarazin, C.; Wong, K.

    2018-03-01

    Context. We present the results of a new Chandra study of the galaxy cluster Abell 2626. The radio emission of the cluster shows a complex system of four symmetric arcs without known correlations with the thermal X-ray emission. The mirror symmetry of the radio arcs toward the center and the presence of two optical cores in the central galaxy suggested that they may be created by pairs of precessing radio jets powered by dual active galactic nuclei (AGNs) inside the core dominant galaxy. However, previous observations failed to observe the second jetted AGN and the spectral trend due to radiative age along the radio arcs, thus challenging this interpretation. Aim. The new Chandra observation had several scientific objectives, including the search for the second AGN that would support the jet precession model. We focus here on the detailed study of the local properties of the thermal and non-thermal emission in the proximity of the radio arcs, in order to obtain further insights into their origin. Methods: We performed a standard data reduction of the Chandra dataset deriving the radial profiles of temperature, density, pressure and cooling time of the intra-cluster medium. We further analyzed the two-dimensional (2D) distribution of the gas temperature, discovering that the south-western junction of the radio arcs surrounds the cool core of the cluster. Results: We studied the X-ray surface brightness and spectral profiles across the junction, finding a cold front spatially coincident with the radio arcs. This may suggest a connection between the sloshing of the thermal gas and the nature of the radio filaments, raising new scenarios for their origin. A tantalizing possibility is that the radio arcs trace the projection of a complex surface connecting the sites where electrons are most efficiently reaccelerated by the turbulence that is generated by the gas sloshing. In this case, diffuse emission embedded by the arcs and with extremely steep spectrum should be

  14. X-ray Variability In Extragalactic Jets as Seen by Chandra

    Science.gov (United States)

    Trevor, Max; Meyer, Eileen; Georganopoulos, Markos; Aubin, Sam; Hewitt, Jennifer; DeNigris, Natalie; Whitley, Kevin

    2018-01-01

    The unrivaled spatial resolution of Chandra has lead to the detection of over 100 extragalactic jetsemitting X-rays on kiloparsec scales, far from the central AGN. These jets are understood to be powerful redistributors of energy on galactic and extragalactic scales, with important effects on galaxy evolution and cluster heating. However, we lack an understanding of many important jet properties, including the particle makeup, particle acceleration characteristics, and total energy content, and even how fast the jet is at kpc scales. In the most powerful jets, a persistently open question is the nature of the emission mechanism for the Chandra-observed X-rays. While inverse Compton upscattering of CMB photons (IC/CMB) by a still-relativistic jet is widely adopted, our group has very recently ruled it out in several cases, suggesting that the X-rays from powerful sources, like the low-power jets, have a synchrotron origin, albeit one with unknown origins, requiring in-situ lepton acceleration at least up to 100 TeV. A very efficient way to extend this result to many more sources is to check for variability of the large scale jet X-ray emission, something that is definitively not expected in the case of IC/CMB due to the extremely long cooling times of the electrons responsible for the emission, but it is plausible if the X-rays are of synchrotron nature. Based on previously published observations of X-ray variability in the jets of M87 and Pictor A, as well as preliminary results suggesting variability in two more powerful jets, we have examined archival observations of over 40 jets which have been imaged twice or more with Chandra for variability, with timescales of a few to nearly 14 years. This analysis has two main goals, namely (i) to confirm a synchrotron origin for the X-rays in powerful sources, as variability is inconsistent with the competing IC/CMB model and (ii) to use the timescales and characteristics (e.g., spectral changes) of any detected X

  15. Deep Chandra Survey of the Small Magellanic Cloud. II. Timing Analysis of X-Ray Pulsars

    Energy Technology Data Exchange (ETDEWEB)

    Hong, JaeSub; Antoniou, Vallia; Zezas, Andreas; Drake, Jeremy J.; Plucinsky, Paul P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Haberl, Frank [Max-Planck-Institut für extraterrestrische Physik, Giessenbach straße, D-85748 Garching (Germany); Sasaki, Manami [Friedrich-Alexander-Universität Erlangen-Nürnberg, Sternwartstrasse 7, 96049 Bamberg (Germany); Laycock, Silas, E-mail: jaesub@head.cfa.harvard.edu [Department of Physics, University of Massachusetts Lowell, MA 01854 (United States)

    2017-09-20

    We report the timing analysis results of X-ray pulsars from a recent deep Chandra survey of the Small Magellanic Cloud (SMC). We analyzed a total exposure of 1.4 Ms from 31 observations over a 1.2 deg{sup 2} region in the SMC under a Chandra X-ray Visionary Program. Using the Lomb–Scargle and epoch-folding techniques, we detected periodic modulations from 20 pulsars and a new candidate pulsar. The survey also covered 11 other pulsars with no clear sign of periodic modulation. The 0.5–8 keV X-ray luminosity ( L {sub X} ) of the pulsars ranges from 10{sup 34} to 10{sup 37} erg s{sup −1} at 60 kpc. All of the Chandra sources with L {sub X} ≳ 4 × 10{sup 35} erg s{sup −1} exhibit X-ray pulsations. The X-ray spectra of the SMC pulsars (and high-mass X-ray binaries) are in general harder than those of the SMC field population. All but SXP 8.02 can be fitted by an absorbed power-law model with a photon index of Γ ≲ 1.5. The X-ray spectrum of the known magnetar SXP 8.02 is better fitted with a two-temperature blackbody model. Newly measured pulsation periods of SXP 51.0, SXP 214, and SXP 701, are significantly different from the previous XMM-Newton and RXTE measurements. This survey provides a rich data set for energy-dependent pulse profile modeling. Six pulsars show an almost eclipse-like dip in the pulse profile. Phase-resolved spectral analysis reveals diverse spectral variations during pulsation cycles: e.g., for an absorbed power-law model, some exhibit an (anti)-correlation between absorption and X-ray flux, while others show more intrinsic spectral variation (i.e., changes in photon indices).

  16. Chandra Observations of Galaxy Zoo Mergers: Frequency of Binary Active Nuclei in Massive Mergers

    Science.gov (United States)

    Teng, Stacy H.; Schawinski, Kevin; Urry, C. Megan; Darg, Dan W.; Kaviraj, Sugata; Oh, Kyuseok; Bonning, Erin W.; Cardamone, Carolin N.; Keel, William C.; Lintott, Chris J.; hide

    2012-01-01

    We present the results from a Chandra pilot study of 12 massive galaxy mergers selected from Galaxy Zoo. The sample includes major mergers down to a host galaxy mass of 1011 M that already have optical AGN signatures in at least one of the progenitors. We find that the coincidences of optically selected active nuclei with mildly obscured (N(sub H) approx merger is found to have confirmed binary X-ray nuclei, though the X-ray emission from its southern nucleus could be due solely to star formation. Thus, the occurrences of binary AGN in these mergers are rare (0-8%), unless most merger-induced active nuclei are very heavily obscured or Compton thick.

  17. Neutron Stars and Black Holes New clues from Chandra and XMM-Newton

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit

    2002-01-01

    Neutron stars and black holes, the most compact astrophysical objects, have become observable in many different ways during the last few decades. We will first review the phenomenology and properties of neutron stars and black holes (stellar and supermassive) as derived from multiwavelength observatories. Recently much progress has been made by means of the new powerful X-ray observatories Chandra and XMM-Newton which provide a substantial increase in sensitivity as well as spectral and angular resolution compared with previous satellites like ROSAT and ASCA. We shall discuss in more detail two recent topics: (1) The attempts to use X-ray spectroscopy for measuring the radii of neutron stars which depend on the equation of state at supranuclear densities. Have quark stars been detected? (2) The diagnostics of the strong gravity regions around supermassive black holes using X-ray spectroscopy.

  18. Lessons from the development and operation of the Chandra x-ray observatory

    Science.gov (United States)

    Schwartz, Daniel A.

    2014-07-01

    Genuine teamwork was a key ingredient of the success of the Chandra x-ray observatory mission. Examples are the science center personnel working as part of the instrument principal investigators (IPI) teams during pre-launch development, the Smithsonian Astrophysical Observatory (SAO) supporting NASA/Marshall Space Flight Center (MSFC) by directly working with the prime contractor, TRW (now Northrop Grumman Aerospace Systems), and TRW acceptance of outside scientists performing the data reduction and analysis for qualification of the aspect camera. An end-to-end thread was defined early on, based on the MSFC/SAO operation of the Einstein observatory x-ray telescope, and covered the cycle from solicitation and peer review of observation proposals through scheduling to data processing and delivery. An open science working group chaired by MSFC included instrument principal investigators and interdisciplinary scientists spanning diverse astrophysical and instrumental expertise.

  19. Chandra Observations of the Evening Core of the Starburst Galaxy NGC 253

    Science.gov (United States)

    Weaver, K. A.; Heckman, T. M.; Dahlem, M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    Chandra observations of the core of the nearby starburst galaxy NGC 253 reveal a heavily absorbed source of hard X-rays embedded within the nuclear starburst region. The source has an unabsorbed, 2 to 10 keV luminosity of greater than or equal to 10(exp 39) erg per s and photoionizes the surrounding gas. We observe this source through a dusty torus with a neutral absorbing column density of N(sub eta) approximately 2 x 10(exp 23)cm (exp -2). The torus is hundreds of pc across and collimates the starburst-driven nuclear outflow. We suggest that the ionizing source is an intermediate-mass black hole or a weakly accreting supermassive black hole, which may signal the beginnings or endings of AGN (active galactic nuclei) activity.

  20. Unifying X-ray winds in radio galaxies with Chandra HETG

    Science.gov (United States)

    Tombesi, Francesco

    2013-09-01

    X-ray winds are routinely observed in the spectra of Seyfert galaxies. They can be classified as warm absorbers (WAs), with v~100-1,000km/s, and ultra-fast outflows (UFOs), with v>10,000km/s. In stark contrast, the lack of sensitive enough observations allowed the detection of WAs or UFOs only in very few radio galaxies. Therefore, we propose to observe a small sample of three radio galaxies with the Chandra HETG - 3C111 for 150ks, 3C390.3 for 150ks and 3C120 for 200ks - to detect and study in detail their WAs. We will quantify the importance of mechanical feedback from winds in radio galaxies and compare them to the radio jet power. We will also test whether WAs and UFOs can be unified in a single, multi-phase and multi-scale outflow, as recently reported for Seyferts.

  1. CHANDRA AND SUZAKU OBSERVATIONS OF THE Be/X-RAY STAR HD110432

    International Nuclear Information System (INIS)

    Torrejón, J. M.; Schulz, N. S.; Nowak, M. A.

    2012-01-01

    We present an analysis of a pointed 141 ks Chandra high-resolution transmission gratings observation of the Be X-ray emitting star HD110432, a prominent member of the γ Cas analogs. This observation represents the first high-resolution spectrum taken for this source as well as the longest uninterrupted observation of any γ Cas analog. The Chandra light curve shows a high variability but its analysis fails to detect any coherent periodicity up to a frequency of 0.05 Hz. Hardness ratio versus intensity analyses demonstrate that the relative contributions of the [1.5-3] Å, [3-6] Å, and [6-16] Å energy bands to the total flux change rapidly in the short term. The analysis of the Chandra High Energy Transmission Grating (HETG) spectrum shows that, to correctly describe the spectrum, three model components are needed. Two of those components are optically thin thermal plasmas of different temperatures (kT ≈ 8-9 and 0.2-0.3 keV, respectively) described by the models vmekal or bvapec. The Fe abundance in each of these two components appears equal within the errors and is slightly subsolar with Z ≈ 0.75 Z ☉ . The bvapec model better describes the Fe L transitions, although it cannot fit well the Na XI Lyα line at 10.02 Å, which appears to be overabundant. Two different models seem to describe well the third component. One possibility is a third hot optically thin thermal plasma at kT = 16-21 keV with an Fe abundance Z ≈ 0.3 Z ☉ , definitely smaller than for the other two thermal components. Furthermore, the bvapec model describes well the Fe K shell transitions because it accounts for the turbulence broadening of the Fe XXV and Fe XXVI lines with a v turb ≈ 1200 km s –1 . These two lines, contributed mainly by the hot thermal plasma, are significantly wider than the Fe Kα line whose FWHM ☉ , and a very hot second plasma with kT ≈ 33 keV or, alternatively, a power law with photon index of Γ = 1.58. In either case, each one of the two components

  2. PROBING WOLF–RAYET WINDS: CHANDRA/HETG X-RAY SPECTRA OF WR 6

    Energy Technology Data Exchange (ETDEWEB)

    Huenemoerder, David P.; Schulz, N. S. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge, MA 02139 (United States); Gayley, K. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Hamann, W.-R.; Oskinova, L.; Shenar, T. [Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24/25, D-14476 Potsdam (Germany); Ignace, R. [Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37614 (United States); Nichols, J. S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS 34, Cambridge, MA 02138 (United States); Pollock, A. M. T., E-mail: dph@space.mit.edu, E-mail: ken.gayley@gmail.com, E-mail: wrh@astro.physik.uni-potsdam.de, E-mail: lida@astro.physik.uni-potsdam.de, E-mail: shtomer@astro.physik.uni-potsdam.de, E-mail: ignace@mail.etsu.edu, E-mail: jnichols@cfa.harvard.edu [European Space Agency, ESAC, Apartado 78, E-28691 Villanueva de la Cañada (Spain)

    2015-12-10

    With a deep Chandra/HETGS exposure of WR 6, we have resolved emission lines whose profiles show that the X-rays originate from a uniformly expanding spherical wind of high X-ray-continuum optical depth. The presence of strong helium-like forbidden lines places the source of X-ray emission at tens to hundreds of stellar radii from the photosphere. Variability was present in X-rays and simultaneous optical photometry, but neither were correlated with the known period of the system or with each other. An enhanced abundance of sodium revealed nuclear-processed material, a quantity related to the evolutionary state of the star. The characterization of the extent and nature of the hot plasma in WR 6 will help to pave the way to a more fundamental theoretical understanding of the winds and evolution of massive stars.

  3. Deep Chandra Observations of HCG 16. I. Active Nuclei, Star Formation, and Galactic Winds

    Science.gov (United States)

    O'Sullivan, E.; Zezas, A.; Vrtilek, J. M.; Giacintucci, S.; Trevisan, M.; David, L. P.; Ponman, T. J.; Mamon, G. A.; Raychaudhury, S.

    2014-10-01

    We present new, deep Chandra X-ray and Giant Metrewave Radio Telescope 610 MHz observations of the spiral-galaxy-rich compact group HCG 16, which we use to examine nuclear activity, star formation, and high-luminosity X-ray binary populations in the major galaxies. We confirm the presence of obscured active nuclei in NGC 833 and NGC 835, and identify a previously unrecognized nuclear source in NGC 838. All three nuclei are variable on timescales of months to years, and for NGC 833 and NGC 835 this is most likely caused by changes in accretion rate. The deep Chandra observations allow us to detect for the first time an Fe Kα emission line in the spectrum of the Seyfert 2 nucleus of NGC 835. We find that NGC 838 and NGC 839 are both starburst-dominated systems, with only weak nuclear activity, in agreement with previous optical studies. We estimate the star formation rates in the two galaxies from their X-ray and radio emission, and compare these results with estimates from the infrared and ultraviolet bands to confirm that star formation in both galaxies is probably declining after galaxy-wide starbursts were triggered ~400-500 Myr ago. We examine the physical properties of their galactic superwinds, and find that both have temperatures of ~0.8 keV. We also examine the X-ray and radio properties of NGC 848, the fifth largest galaxy in the group, and show that it is dominated by emission from its starburst.

  4. Deep Chandra observations of HCG 16. I. Active nuclei, star formation, and galactic winds

    Energy Technology Data Exchange (ETDEWEB)

    O' Sullivan, E.; Zezas, A.; Vrtilek, J. M.; David, L. P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Giacintucci, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Trevisan, M. [Instituto Nacional de Pesquisas Espaciais, Av. dos Astronautas 1758, 12227-010, São José dos Campos (Brazil); Ponman, T. J.; Raychaudhury, S. [School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT (United Kingdom); Mamon, G. A., E-mail: eosullivan@cfa.harvard.edu [Institut d' Astrophysique de Paris (UMR 7095 CNRS and UMPC), 98 bis Bd Arago, F-75014 Paris (France)

    2014-10-01

    We present new, deep Chandra X-ray and Giant Metrewave Radio Telescope 610 MHz observations of the spiral-galaxy-rich compact group HCG 16, which we use to examine nuclear activity, star formation, and high-luminosity X-ray binary populations in the major galaxies. We confirm the presence of obscured active nuclei in NGC 833 and NGC 835, and identify a previously unrecognized nuclear source in NGC 838. All three nuclei are variable on timescales of months to years, and for NGC 833 and NGC 835 this is most likely caused by changes in accretion rate. The deep Chandra observations allow us to detect for the first time an Fe Kα emission line in the spectrum of the Seyfert 2 nucleus of NGC 835. We find that NGC 838 and NGC 839 are both starburst-dominated systems, with only weak nuclear activity, in agreement with previous optical studies. We estimate the star formation rates in the two galaxies from their X-ray and radio emission, and compare these results with estimates from the infrared and ultraviolet bands to confirm that star formation in both galaxies is probably declining after galaxy-wide starbursts were triggered ∼400-500 Myr ago. We examine the physical properties of their galactic superwinds, and find that both have temperatures of ∼0.8 keV. We also examine the X-ray and radio properties of NGC 848, the fifth largest galaxy in the group, and show that it is dominated by emission from its starburst.

  5. DISSECTING PHOTOMETRIC REDSHIFT FOR ACTIVE GALACTIC NUCLEUS USING XMM- AND CHANDRA-COSMOS SAMPLES

    International Nuclear Information System (INIS)

    Salvato, M.; Hasinger, G.; Ilbert, O.; Rau, A.; Brusa, M.; Bongiorno, A.; Civano, F.; Elvis, M.; Zamorani, G.; Vignali, C.; Comastri, A.; Bardelli, S.; Bolzonella, M.; Cappelluti, N.; Aussel, H.; Le Floc'h, E.; Fiore, F.; Mainieri, V.; Capak, P.; Caputi, K.

    2011-01-01

    In this paper, we release accurate photometric redshifts for 1692 counterparts to Chandra sources in the central square degree of the Cosmic Evolution Survey (COSMOS) field. The availability of a large training set of spectroscopic redshifts that extends to faint magnitudes enabled photometric redshifts comparable to the highest quality results presently available for normal galaxies. We demonstrate that morphologically extended, faint X-ray sources without optical variability are more accurately described by a library of normal galaxies (corrected for emission lines) than by active galactic nucleus (AGN) dominated templates, even if these sources have AGN-like X-ray luminosities. Preselecting the library on the bases of the source properties allowed us to reach an accuracy σ Δz/(1+z spec ) ∼0.015 with a fraction of outliers of 5.8% for the entire Chandra-COSMOS sample. In addition, we release revised photometric redshifts for the 1735 optical counterparts of the XMM-detected sources over the entire 2 deg 2 of COSMOS. For 248 sources, our updated photometric redshift differs from the previous release by Δz > 0.2. These changes are predominantly due to the inclusion of newly available deep H-band photometry (H AB = 24 mag). We illustrate once again the importance of a spectroscopic training sample and how an assumption about the nature of a source together, with the number and the depth of the available bands, influences the accuracy of the photometric redshifts determined for AGN. These considerations should be kept in mind when defining the observational strategies of upcoming large surveys targeting AGNs, such as eROSITA at X-ray energies and the Australian Square Kilometre Array Pathfinder Evolutionary Map of the Universe in the radio band.

  6. Chandra Contributes to ESA's Integral Detection of Closest Gamma-Ray Burst

    Science.gov (United States)

    2004-08-01

    had pinpointed the approximate position of GRB 031203 in the sky and sent the information to a network of observatories around the world. A few hours later one of them, ESA's XMM-Newton, determined a much more precise position for GRB 031203 and detected a rapidly fading X-ray source, which was subsequently seen by radio and optical telescopes on the ground. This wealth of data allowed astronomers to determine that GRB 031203 went off in a galaxy less than 1300 million light years away, making it the closest GRB ever observed. Even so, the way in which GRB 031203 dimmed with time and the distribution of its energy were not different from those of distant GRBs. Then, scientists started to realise that the concept of the 'standard candle' may not hold. "Being so close should make GRB 031203 appear very bright, but the amount of gamma-rays measured by Integral is about one thousand times less than what we would normally expect from a GRB," Sazonov said. A burst of gamma rays observed in 1998 in a closer galaxy appeared even fainter, about one hundred times less bright than GRB 031203. Astronomers, however, could not conclusively tell whether that was a genuine GRB because the bulk of its energy was emitted mostly as X-rays instead of gamma-rays. The work of Sazonov's team on GRB 031203 now suggests that intrinsically fainter GRBs can indeed exist. A team of US astronomers, coordinated by Alicia Soderberg from the California Institute of Technology, Pasadena (USA), studied the 'afterglow' of GRB 031203 and gave further support to this conclusion. The afterglow, emitted when a GRB's blastwave shocks the diffuse medium around it, can last weeks or months and progressively fades away. Using NASA's Chandra X-ray Observatory, Soderberg and her team saw that the X-ray brightness of the afterglow was about one thousand times fainter than that of typical distant GRBs. The team's observations with the Very Large Array telescope of the National Radio Astronomy Observatory in

  7. PENGARUH PEMERIKSAAN INTERN TERHADAP EFEKTIVITAS PENGENDALIAN INTERN ATAS PERSEDIAAN BAHAN BAKU PADA PT. CHANDRA ASRI PETROCHEMICAL JAKARTA

    Directory of Open Access Journals (Sweden)

    Andi Riyanto

    2016-03-01

      Keyword : Raw Material Inventory, Internal Control, Internal Auditing.   Abstrak - PT. Chandra Asri Petrochemical adalah perusahaan petrokimia terbesar dan terintegrasi secara vertikal di Indonesia. Tujuan penelitian ini adalah untuk mengetahui pengaruh pemeriksaan intern terhadap efektivitas pengendalian intern atas persediaan bahan baku pada PT. Chandra Asri Petrochemical. Metode yang digunakan adalah metode deskriptif analitis dengan pendekatan kuantitatif. Populasi berjumlah 27 pegawai dan semua populasi digunakan sebagai sampel dengan teknik sampling jenuh. Dari perhitungan uji statistik menggunakan aplikasi SPSS versi 20, diperoleh nilai thitung untuk variabel pemeriksaan intern adalah 5,799 dengan df = 24 pada signifikansi (α 0,05, diperoleh ttabel sebesar 2,064, maka keputusan uji yang diambil adalah H0 ditolak. Artinya bahwa pemeriksaan intern berpengaruh signifikan terhadap efektivitas pengendalian intern atas persediaan bahan baku.   Kata Kunci : Pemeriksaan Intern, Pengendalian Intern, Persediaan Bahan Baku.

  8. The iron K-shell features of MXB 1728-34 from a simultaneous Chandra-RXTE observation

    NARCIS (Netherlands)

    D'Aí, A.; di Salvo, T.; Iaria, R.; Méndez, M.; Burderi, L.; Lavagetto, G.; Lewin, W.H.G.; Robba, N.R.; Stella, L.; van der Klis, M.

    2006-01-01

    We report on a simultaneous Chandra and RossiXTE observation of the low-mass X-ray binary atoll bursting source MXB 1728-34 performed on 2002 March 3-5. We fit the 1.2-35 keV continuum spectrum with a blackbody plus a Comptonized component. Large residuals at 6-10 keV can be fitted by a broad (

  9. Chandra Reveals Heavy Obscuration and Circumnuclear Star Formation in Seyfert 2 Galaxy NGC 4968

    Science.gov (United States)

    LaMassa, Stephanie M.; Yaqoob, Tahir; Levenson, N. A.; Boorman, Peter; Heckman, Timothy M.; Gandhi, Poshak; Rigby, Jane R.; Urry, C. Megan; Ptak, Andrew F.

    2017-01-01

    We present the Chandra imaging and spectral analysis of NGC 4968, a nearby (z = 0.00986) Seyfert 2 galaxy. We discover extended (approx. 1 kpc) X-ray emission in the soft band (0.5-2 keV) that is neither coincident with the narrow line region nor the extended radio emission. Based on spectral modeling, it is linked to on-going star formation [approx. 2.6-4 Mass compared to Earth yr(exp.- 1)]. The soft emission at circumnuclear scales (inner approx. 400 pc) originates from hot gas, with kT approx. 0.7 keV, while the most extended thermal emission is cooler (kT approx. 0.3 keV). We refine previous measurements of the extreme Fe K alpha equivalent width in this source (EW 2.5 + 2.6/-1.0 keV), which suggests the central engine is completely embedded within Compton-thick levels of obscuration. Using physically motivated models fit to the Chandra spectrum, we derive a Compton-thick column density [N(sub H) is greater than 1.25× 10(exp 24) cm(exp.- 2)] and an intrinsic hard (2-10 keV) X-ray luminosity of approx. 3-8× 10(exp. 42) erg s(exp. - 1) (depending on the presumed geometry of the obscurer), which is over two orders of magnitude larger than that observed. The large Fe K Alpha EW suggests a spherical covering geometry, which could be confirmed with X-ray measurements above 10 keV. NGC 4968 is similar to other active galaxies that exhibit extreme Fe K Alpha EWs (i.e., greater than 2 keV) in that they also contain on-going star formation. This work supports the idea that gas associated with nuclear star formation may increase the covering factor of the enshrouding gas and play a role in obscuring active galactic nuclei.

  10. HDE 245059: A WEAK-LINED T TAURI BINARY REVEALED BY CHANDRA AND KECK

    International Nuclear Information System (INIS)

    Baldovin-Saavedra, C.; Audard, M.; Duchene, G.; Guedel, M.; Skinner, S.L.; Paerels, F. B. S.; Ghez, A.; McCabe, C.

    2009-01-01

    We present the Chandra High Energy Transmission Grating Spectrometer and Keck observations of HDE 245059, a young weak-lined T Tauri star (WTTS), member of the pre-main-sequence group in the λ Orionis Cluster. Our high spatial resolution, near-infrared observations with Keck reveal that HDE 245059 is in fact a binary separated by 0.''87, probably composed of two WTTS based on their color indices. Based on this new information we have obtained an estimate of the masses of the binary components; ∼3 M sun and ∼2.5 M sun for the north and south components, respectively. We have also estimated the age of the system to be ∼2-3 Myr. We detect both components of the binary in the zeroth-order Chandra image and in the grating spectra. The light curves show X-ray variability of both sources and in particular a flaring event in the weaker southern component. The spectra of both stars show similar features: a combination of cool and hot plasma as demonstrated by several iron lines from Fe XVII to Fe XXV and a strong bremsstrahlung continuum at short wavelengths. We have fitted the combined grating and zeroth-order spectrum (considering the contribution of both stars) in XSPEC. The coronal abundances and emission measure distribution for the binary have been obtained using different methods, including a continuous emission measure distribution and a multi-temperature approximation. In all cases we have found that the emission is dominated by plasma between ∼8 and ∼15 MK a soft component at ∼4 MK and a hard component at ∼50 MK are also detected. The value of the hydrogen column density was low, N H ∼ 8 x 10 19 cm -2 , likely due to the clearing of the inner region of the λ Orionis cloud, where HDE 245059 is located. The abundance pattern shows an inverse first ionization potential effect for all elements from O to Fe, the only exception being Ca. To obtain the properties of the binary components, a 3-T model was fitted to the individual zeroth-order spectra

  11. Chandra observations of Comet 9P/Tempel 1 during the Deep Impact campaign

    Science.gov (United States)

    Lisse, C. M.; Dennerl, K.; Christian, D. J.; Wolk, S. J.; Bodewits, D.; Zurbuchen, T. H.; Hansen, K. C.; Hoekstra, R.; Combi, M.; Fry, C. D.; Dryer, M.; Mäkinen, T.; Sun, W.

    2007-10-01

    We present results from the Chandra X-ray Observatory's extensive campaign studying Comet 9P/Tempel 1 (T1) in support of NASA's Deep Impact (DI) mission. T1 was observed for ˜295 ks between 30th June and 24th July 2005, and continuously for ˜64 ks on July 4th during the impact event. X-ray emission qualitatively similar to that observed for the collisionally thin Comet 2P/Encke system [Lisse, C.M., Christian, D.J., Dennerl, K., Wolk, S.J., Bodewits, D., Hoekstra, R., Combi, M.R., Mäkinen, T., Dryer, M., Fry, C.D., Weaver, H., 2005b. Astrophys. J. 635 (2005) 1329-1347] was found, with emission morphology centered on the nucleus and emission lines due to C, N, O, and Ne solar wind minor ions. The comet was relatively faint on July 4th, and the total increase in X-ray flux due to the Deep Impact event was small, ˜20% of the immediate pre-impact value, consistent with estimates that the total coma neutral gas release due to the impact was 5×10 kg ( ˜10 h of normal emission). No obvious prompt X-ray flash due to the impact was seen. Extension of the emission in the direction of outflow of the ejecta was observed, suggesting the presence of continued outgassing of this material. Variable spectral features due to changing solar wind flux densities and charge states were clearly seen. Two peaks, much stronger than the man-made increase due to Deep Impact, were found in the observed X-rays on June 30th and July 8th, 2005, and are coincident with increases in the solar wind flux arriving at the comet. Modeling of the Chandra data using observed gas production rates and ACE solar wind ion fluxes with a CXE mechanism for the emission is consistent, overall, with the temporal and spectral behavior expected for a slow, hot wind typical of low latitude emission from the solar corona interacting with the comet's neutral coma, with intermittent impulsive events due to solar flares and coronal mass ejections.

  12. Identifying the Location in the Host Galaxy of Short GRB 1111l7A with the Chandra Sub- Arcsecond Position

    Science.gov (United States)

    Sakamoto, Takanori; Troja, E.; Aoki, K.; Guiriec, S.; Im, M.; Leloudas, G.; Malesani, D.; Melandri, A.; deUgartePostigo, A.; Urata, Y.; hide

    2012-01-01

    We present our successful program using Chandra for identifying the X-ray afterglow with sub-arcsecond accuracy for the short GRB 111117A d iscovered by Swift and Fermi. Thanks to our rapid target of opportuni ty request, Chandra clearly detected the X-ray afterglow, whereas no optical afterglow was found in deep optical observations. Instead, we clearly detect the host galaxy in optica; and also in near-infrared b ands. We found that the best photometric redshift fitofthe host is z = 1.31:(+0.46/-0.23) (90% confidence), making it one of the highest redshift short GRBs. Furthermore, we see an offset of 1.0+/-O.2 arcseco nds, which corresponds to 8.4+/-1.7 kpc aSBuming z= 1.31, between the host and the afterglow position. We discuss the importance of using Chandra for obtaining sub-arcsecond localization of the afterglow in X -rays for short GRBs to study GRB environments in great detail.

  13. STAR FORMATION IN THE CHANDRA DEEP FIELD SOUTH: OBSERVATIONS CONFRONT SIMULATIONS

    International Nuclear Information System (INIS)

    Damen, Maaike; Franx, Marijn; Foerster Schreiber, Natascha M.; Labbe, Ivo; Toft, Sune; Van Dokkum, Pieter G.; Wuyts, Stijn

    2009-01-01

    We investigate the star formation history of the universe using FIREWORKS, a multiwavelength survey of the Chandra Deep Field South. We study the evolution of the specific star formation rate (sSFR) with redshift in different mass bins from z = 0 to z ∼ 3. We find that the sSFR increases with redshift for all masses. The logarithmic increase of the sSFR with redshift is nearly independent of mass, but this cannot yet be verified at the lowest-mass bins at z>0.8, due to incompleteness. We convert the sSFRs to a dimensionless growth rate to facilitate a comparison with a semianalytic galaxy formation model that was implemented on the Millennium Simulation. The model predicts that the growth rates and sSFRs increase similarly with redshift for all masses, consistent with the observations. However, we find that for all masses, the inferred observed growth rates increase more rapidly with redshift than the model predictions. We discuss several possible causes for this discrepancy, ranging from field-to-field variance, conversions to SFR, and shape of the initial mass function. We find that none of these can solve the discrepancy completely. We conclude that the models need to be adapted to produce the steep increase in growth rate between redshift z = 0 and z = 1.

  14. An Archival Chandra and XMM-Newton Survey of Type 2 Quasars

    Science.gov (United States)

    Jia, Jianjun; Ptak, Andrew Francis; Heckman, Timothy; Zakamska, Nadia L.

    2013-01-01

    In order to investigate obscuration in high-luminosity type 2 active galactic nuclei (AGNs), we analyzed Chandra and XMM-Newton archival observations for 71 type 2 quasars detected at 0.05 100 eV in the rest frame) and we detect this line in the other sources through a joint fit (spectral stacking). The correlation between the Fe K alpha and [O III] fluxes and the inverse correlation of the equivalent width of the Fe Ka line with the ratio of hard X-ray and [O III] fluxes is consistent with previous results for lower luminosity Seyfert 2 galaxies. We conclude that obscuration is the cause of the weak hard X-ray emission rather than intrinsically low X-ray luminosities. We find that about half of the population of optically selected type 2 quasars are likely to be Compton thick. We also find no evidence that the amount of X-ray obscuration depends on the AGN luminosity (over a range of more than three orders of magnitude in luminosity).

  15. HIGH-RESOLUTION CHANDRA HETG SPECTROSCOPY OF V404 CYGNI IN OUTBURST

    Energy Technology Data Exchange (ETDEWEB)

    King, Ashley L.; Morningstar, Warren [Department of Physics, 382 Via Pueblo Mall, Stanford, CA 94305 (United States); Miller, Jon M.; Reynolds, Mark T. [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109-1107 (United States); Raymond, John, E-mail: ashking@stanford.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-11-10

    As one of the best-characterized stellar-mass black holes, with good measurements of its mass, distance, and inclination, V404 Cyg is the ideal candidate to study Eddington-limited accretion episodes. After a long quiescent period, V404 Cyg underwent a new outburst in 2015 June. We obtained two Chandra HETG exposures of 20 and 25 ks. Many strong emission lines are observed; the ratio of Si He-like triplet lines gives an estimate for the formation region distance of 4 × 10{sup 11} cm. A narrow Fe Kα line is detected with an equivalent width greater than 1 keV in many epochs, signaling that we do not directly observe the central engine. Obscuration of the central engine and strong narrow emission lines signal that the outer disk may be illuminated, and its structure may help to drive the strong variability observed in V404 Cyg. In the highest flux phases, strong P-Cygni profiles consistent with a strong disk wind are observed, likely radiation or thermally driven as V404 Cyg approaches its Eddington limit. The kinetic power of this wind may be extremely high at >0.1 L{sub Bol}.

  16. CORRELATION OF CHANDRA PHOTONS WITH THE RADIO GIANT PULSES FROM THE CRAB PULSAR

    Energy Technology Data Exchange (ETDEWEB)

    Bilous, A. V. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); McLaughlin, M. A. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Kondratiev, V. I. [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands); Ransom, S. M., E-mail: avb3k@virginia.edu [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)

    2012-04-10

    No apparent correlation was found between giant pulses (GPs) and X-ray photons from the Crab pulsar during 5.4 hr of simultaneous observations with the Green Bank Telescope at 1.5 GHz and Chandra X-Ray Observatory primarily in the energy range of 1.5-4.5 keV. During the Crab pulsar periods with GPs, the X-ray flux in radio emission phase windows does not change more than by {+-}10% for main pulse (MP) GPs and {+-}30% for interpulse (IP) GPs. During GPs themselves, the X-ray flux does not change by more than two times for MP GPs and five times for IP GPs. All limits quoted are compatible with 2{sigma} fluctuations of the X-ray flux around the sets of false GPs with random arrival times. The results speak in favor of changes in plasma coherence as the origin of GPs. However, the results do not rule out variations in the rate of particle creation if the particles that emit coherent radio emission are mostly at the lowest Landau level.

  17. CORRELATION OF CHANDRA PHOTONS WITH THE RADIO GIANT PULSES FROM THE CRAB PULSAR

    International Nuclear Information System (INIS)

    Bilous, A. V.; McLaughlin, M. A.; Kondratiev, V. I.; Ransom, S. M.

    2012-01-01

    No apparent correlation was found between giant pulses (GPs) and X-ray photons from the Crab pulsar during 5.4 hr of simultaneous observations with the Green Bank Telescope at 1.5 GHz and Chandra X-Ray Observatory primarily in the energy range of 1.5-4.5 keV. During the Crab pulsar periods with GPs, the X-ray flux in radio emission phase windows does not change more than by ±10% for main pulse (MP) GPs and ±30% for interpulse (IP) GPs. During GPs themselves, the X-ray flux does not change by more than two times for MP GPs and five times for IP GPs. All limits quoted are compatible with 2σ fluctuations of the X-ray flux around the sets of false GPs with random arrival times. The results speak in favor of changes in plasma coherence as the origin of GPs. However, the results do not rule out variations in the rate of particle creation if the particles that emit coherent radio emission are mostly at the lowest Landau level.

  18. Chandra X-Rays from the Redshift 7.54 Quasar ULAS J1342+0928

    Science.gov (United States)

    Bañados, Eduardo; Connor, Thomas; Stern, Daniel; Mulchaey, John; Fan, Xiaohui; Decarli, Roberto; Farina, Emanuele P.; Mazzucchelli, Chiara; Venemans, Bram P.; Walter, Fabian; Wang, Feige; Yang, Jinyi

    2018-04-01

    We present a 45 ks Chandra observation of the quasar ULAS J1342+0928 at z = 7.54. We detect {14.0}-3.7+4.8 counts from the quasar in the observed-frame energy range 0.5–7.0 keV (6σ detection), representing the most distant non-transient astronomical source identified in X-rays to date. The present data are sufficient only to infer rough constraints on the spectral parameters. We find an X-ray hardness ratio of { \\mathcal H }{ \\mathcal R }=-{0.51}-0.28+0.26 between the 0.5–2.0 keV and 2.0–7.0 keV ranges and derive a power-law photon index of {{Γ }}={1.95}-0.53+0.55. Assuming a typical value for high-redshift quasars of Γ = 1.9, ULAS J1342+0928 has a 2–10 keV rest-frame X-ray luminosity of {L}2-10={11.6}-3.5+4.3× {10}44 {erg} {{{s}}}-1. Its X-ray-to-optical power-law slope is {α }OX}=-{1.67}-0.10+0.16, consistent with the general trend indicating that the X-ray emission in the most bolometrically powerful quasars is weaker relative to their optical emission.

  19. The Incidence of Buried Dual AGN in Advanced Mergers: New results from Chandra

    Science.gov (United States)

    Pfeifle, Ryan William; Satyapal, Shobita; Secrest, Nathan; Gliozzi, Mario; Ricci, Claudio; Ellison, Sara L.; Blecha, Laura; Rothberg, Barry; Constantin, Anca

    2018-01-01

    Since the vast majority of galaxies contain supermassive black holes (SMBHs) and galaxy interactions trigger nuclear gas accretion, a direct consequence of the hierarchical model of galaxy formation would be the existence of dual active galactic nuclei (AGN). The existence, frequency, and characteristics of such dual AGN have important astrophysical implications on the SMBH mass function, the interplay between SMBHs and the host galaxy, and the M-sigma relation. Despite decades of searching, and strong theoretical reasons for their existence, observationally confirmed cases of dual AGN are extremely rare, and most have been discovered serendipitously. Using the all-sky WISE survey, we identified a population of over one hundred strongly interacting galaxies that display extreme red mid-infrared colors thus far exclusively associated with extragalactic sources possessing powerful AGN. In a recent Chandra, XMM-Newton, and NuSTAR investigation of advanced mergers selected by WISE, we find dual AGN candidates in 8 out of 15 mergers, all of which show no evidence for AGN based on optical spectroscopy. Our results demonstrate that 1) optical studies miss a significant fraction of single and dual AGN in advanced mergers, and 2) mid-infrared pre-selection is extremely effective in identifying dual AGN candidates in late-stage mergers. Our multi-wavelength observations suggest that the buried AGN in these mergers are highly absorbed, with intrinsic column densities in excess of NH > 1024 cm-2, consistent with hydrodynamic simulations.

  20. Multiwavelength counterparts of the point sources in the Chandra Source Catalog

    Science.gov (United States)

    Reynolds, Michael; Civano, Francesca Maria; Fabbiano, Giuseppina; D'Abrusco, Raffaele

    2018-01-01

    The most recent release of the Chandra Source Catalog (CSC) version 2.0 comprises more than $\\sim$350,000 point sources, down to fluxes of $\\sim$10$^{-16}$ erg/cm$^2$/s, covering $\\sim$500 deg$^2$ of the sky, making it one of the best available X-ray catalogs to date. There are many reasons to have multiwavelength counterparts for sources, one such reason is that X-ray information alone is not enough to identify the sources and divide them between galactic and extragalactic origin, therefore multiwavelength data associated to each X-ray source is crucial for classification and scientific analysis of the sample. To perform this multiwavelength association, we are going to employ the recently released versatile tool NWAY (Salvato et al. 2017), based on a Bayesian algorithm for cross-matching multiple catalogs. NWAY allows the combination of multiple catalogs at the same time, provides a probability for the matches, even in case of non-detection due to different depth of the matching catalogs, and it can be used by including priors on the nature of the sources (e.g. colors, magnitudes, etc). In this poster, we are presenting the preliminary analysis using the CSC sources above the galactic plane matched to the WISE All-Sky catalog, SDSS, Pan-STARRS and GALEX.

  1. Chandra and NuSTAR Follow-up Observations of Swift-BAT-selected AGNs

    Science.gov (United States)

    Marchesi, S.; Tremblay, L.; Ajello, M.; Marcotulli, L.; Paggi, A.; Cusumano, G.; La Parola, V.; Segreto, A.

    2017-10-01

    Based on current models of the cosmic X-ray background (CXB), heavily obscured active galactic nuclei (AGNs) are expected to make up ˜10% of the peak emission of the CXB and ˜20% of the total population of AGNs, yet few of these sources have been recorded and characterized in current surveys. Here we present the Chandra follow-up observation of 14 AGNs detected by Swift-BAT. For five sources in the sample, NuSTAR observations in the 3-80 keV band are also available. The X-ray spectral fitting over the 0.3-150 keV energy range allows us to determine the main X-ray spectral parameters, such as the photon index and the intrinsic absorption, of these objects and to make hypotheses on the physical structures responsible for the observed spectra. We find that 13 of the 14 objects are absorbed AGNs, and one is a candidate Compton-thick AGN, having intrinsic absorption {N}{{H}}> {10}24 cm-2. Finally, we verified that the use of NuSTAR observations is strategic to strongly constrain the properties of obscured AGNs, since the best-fit values we obtained for parameters such as the power-law photon index Γ and the intrinsic absorption {N}{{H}} changed sometimes significantly fitting the spectra with and without the use of NuSTAR data.

  2. The Chandra Deep Field South as a test case for Global Multi Conjugate Adaptive Optics

    Science.gov (United States)

    Portaluri, E.; Viotto, V.; Ragazzoni, R.; Gullieuszik, M.; Bergomi, M.; Greggio, D.; Biondi, F.; Dima, M.; Magrin, D.; Farinato, J.

    2017-04-01

    The era of the next generation of giant telescopes requires not only the advent of new technologies but also the development of novel methods, in order to exploit fully the extraordinary potential they are built for. Global Multi Conjugate Adaptive Optics (GMCAO) pursues this approach, with the goal of achieving good performance over a field of view of a few arcmin and an increase in sky coverage. In this article, we show the gain offered by this technique to an astrophysical application, such as the photometric survey strategy applied to the Chandra Deep Field South as a case study. We simulated a close-to-real observation of a 500 × 500 arcsec2 extragalactic deep field with a 40-m class telescope that implements GMCAO. We analysed mock K-band images of 6000 high-redshift (up to z = 2.75) galaxies therein as if they were real to recover the initial input parameters. We attained 94.5 per cent completeness for source detection with SEXTRACTOR. We also measured the morphological parameters of all the sources with the two-dimensional fitting tools GALFIT. The agreement we found between recovered and intrinsic parameters demonstrates GMCAO as a reliable approach to assist extremely large telescope (ELT) observations of extragalactic interest.

  3. CHANDRA OBSERVATION OF ABELL 1142: A COOL-CORE CLUSTER LACKING A CENTRAL BRIGHTEST CLUSTER GALAXY?

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yuanyuan; Weeren, Reinout van [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Buote, David A. [Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States); Gastaldello, Fabio, E-mail: yuanyuan.su@cfa.harvard.edu [INAF-IASF-Milano, Via E. Bassini 15, I-20133 Milano (Italy)

    2016-04-10

    Abell 1142 is a low-mass galaxy cluster at low redshift containing two comparable brightest cluster galaxies (BCGs) resembling a scaled-down version of the Coma Cluster. Our Chandra analysis reveals an X-ray emission peak, roughly 100 kpc away from either BCG, which we identify as the cluster center. The emission center manifests itself as a second beta-model surface brightness component distinct from that of the cluster on larger scales. The center is also substantially cooler and more metal-rich than the surrounding intracluster medium (ICM), which makes Abell 1142 appear to be a cool-core cluster. The redshift distribution of its member galaxies indicates that Abell 1142 may contain two subclusters, each of which contain one BCG. The BCGs are merging at a relative velocity of ≈1200 km s{sup −1}. This ongoing merger may have shock-heated the ICM from ≈2 keV to above 3 keV, which would explain the anomalous L{sub X}–T{sub X} scaling relation for this system. This merger may have displaced the metal-enriched “cool core” of either of the subclusters from the BCG. The southern BCG consists of three individual galaxies residing within a radius of 5 kpc in projection. These galaxies should rapidly sink into the subcluster center due to the dynamical friction of a cuspy cold dark matter halo.

  4. A Chandra X-Ray Survey of Ejecta in the Cassiopeia A Supernova Remnant

    Science.gov (United States)

    Hwang, Una; Laming, J. Martin

    2011-01-01

    We present a survey of the X-ray emitting ejecta in the Cassiopeia A supernova remnant based on an extensive analysis of over 6000 spectral regions extracted on 2.5-10" angular scales using the Chandra 1 Ms observation. We interpret these results in the context of hydrodynamical models for the evolution of the remnant. The distributions of fitted temperature and ionization age are highly peaked and suggest that the ejecta were subjected to multiple secondary shocks. Based on the fitted emission measure and element abundances, and an estimate of the emitting volume, we derive masses for the X-ray emitting ejecta as well as showing the distribution of the mass of various elements over the remnant. The total shocked Fe mass appears to be roughly 0.14 Solar Mass, which accounts for nearly all of the mass expected in Fe ejecta. We find two populations of Fe ejecta, that associated with normal Si-burning and that associated with alpha-rich freeze-out, with a mass ratio of approximately 2:1. Surprisingly, essentially all of this Fe (both components) is well outside the central regions of the SNR, presumably having been ejected by hydrodynamic instabilities during the explosion. We discuss this, and its implications for the neutron star kick.

  5. Black Hole Masses for Type I Active Galactic Nuclei in the Chandra Cosmos Legacy Survey

    Science.gov (United States)

    Nagaraj, Gautam; Fornasini, Francesca; Civano, Francesca Maria

    2018-01-01

    Tight local relations between SMBH masses and galaxy properties have established the fundamental connection between SMBHs and their host galaxies. However, in order to better understand the coevolution of SMBHs and their host galaxies over cosmic time, we need measurements of black hole masses, AGN luminosities, and galaxy stellar masses from sizable samples of AGN covering lower luminosities than the brightest quasars spanning a wide redshift range. In this study, we report masses of the SMBHs of 224 Type I AGNs from the Chandra COSMOS Legacy Survey as determined by the line widths of Mg II 2798, Hb 4862, and Ha 6564 via scaling relations derived from reverberation mapping. Preliminary comparison with host galaxy luminosities and stellar masses suggests an increase in Eddington ratio with redshift, consistent with previous studies. In addition, our derived SMBH masses fall above the local AGN MBH--M* (galactic stellar mass) relation from Reines & Volonteri (2015), but it is still not clear whether this results from redshift evolution of the MBH--M* relation or from the incompleteness of the spectroscopic surveys available. The SAO REU program is funded by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant AST-1659473, and by the Smithsonian Institution.

  6. Cometary X-rays - the View After the First Chandra Cycle

    Science.gov (United States)

    Lisse, Carey M.

    2001-09-01

    The unexpected discovery of x-ray emission from Comet Hyakutake in March 1996 (Lisse et al. 1996) has produced a number of questions about the physical mechanism producing the radiation. The original detection and subsequent observations (Dennerl et al. 1997, Mumma et al. 1997, Krasnopolsky et al. 1998, Owens et al. 1998, Lisse et al. 1999) have shown that the very soft (best fit thermal bremsstrahlung model kT 0.2 keV) emission is due to an interaction between the solar wind and the comet's atmosphere. Using the results from the 15 comets detected to date in x-rays, we report on the latest results on cometary x-ray emission, including new results from Chandra and XMM. As-observed morphologies, spectra, and light curves will be discussed. Our emphasis will be on understanding the physical mechanism producing the emission, and using this to determine the nature of the cometary coma, the structure of the solar wind in the heliosphere, and the source of the local soft x-ray background. This work has been graciously supported by grants from the NASA Planetary Astronomy and Astrophysical Data Programs.

  7. Cometary X-ray Emission: the View After the First Chandra Observations

    Science.gov (United States)

    Lisse, C. M.

    2002-01-01

    The unexpected discovery of x-ray emission from Comet Hyakutake in March 1996 (Lisse et al. 1996) has produced a number of questions about the physical mechanism producing the radiation. The original detection and subsequent observations (Dennerl et al. 1997, Mumma et al. 1997, Krasnopolsky et al. 1998, Owens et al. 1998, Lisse et al. 1999) have shown that the very soft (best fit thermal bremsstrahlung model kT ~ 0.2 keV) emission is due to an interaction between the solar wind and the comet's atmosphere. Using the results from the 15 comets detected to date in x-rays, we report on the latest results on cometary x-ray emission, including new results from Chandra and XMM. As-observed morphologies, spectra, and light curves will be discussed. Our emphasis will be on understanding the physical mechanism producing the emission, and using this to determine the nature of the cometary coma, the structure of the solar wind in the heliosphere, and the source of the local soft x-ray background. This work has been graciously supported by grants from the NASA Planetary Astronomy and Astrophysical Data Programs.

  8. Deep Chandra Observations of Abell 586: A Remarkably Relaxed Non-Cool-Core Cluster

    Science.gov (United States)

    Richstein, Hannah; Su, Yuanyuan

    2018-01-01

    The dichotomy between cool-core and non-cool-core clusters has been a lasting perplexity in extragalactic astronomy. Nascent cores in non-cool-core clusters may have been disrupted by major mergers, yet the dichotomy cannot be reproduced in cosmology simulations. We present deep Chandra observations of the massive galaxy cluster Abell 586, which resides at z=0.17, thus allowing its gas properties to be measured out to its virial radius. Abell 586 appears remarkably relaxed with a nearly spherical X-ray surface brightness distribution and without any offset between its X-ray and optical centroids. We measure that its temperature profile does not decrease towards the cluster center and its central entropy stays above 100 keV cm2. A non-cool-core emerges in Abell 586 in the absence of any disruptions on the large scale. Our study demonstrates that non-cool-core clusters can be formed without major mergers. The origins of some non-cool-core clusters may be related to conduction, AGN feedback, or preheating.The SAO REU program is funded by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant AST-1659473, and by the Smithsonian Institution.

  9. Evaluación de los modelos de predicción del ACI-08, Eurocódigo 2 y EHE-08, para estimar las propiedades mecánicas del hormigón autocompactante

    Directory of Open Access Journals (Sweden)

    Agranati, G.

    2010-12-01

    Full Text Available The objective of this study is to evaluate the applicability of the ACI-08, EC-2, and EHE-08 models for the estimating of the mechanical properties of self-compacting concrete (SCC. The mechanical properties considered are the modulus of elasticity, tensile strength, and modulus of rupture. In order to statistically evaluate the applicability of the models it was necessary to compile an extensive database that included the experimental results for the various mechanical properties analyzed and the exact dosifications of the mixtures. The first part of the study includes an analysis of each one of the models, together with a regression analysis in order to evaluate the behavior and the adaptability to the different models. The specific characterization parameters for each concrete mixture were used to calculate the various mechanical properties applying the different estimation models. The second part of the analysis consisted in comparing the experimental results with the estimated results for all the mixtures in order to evaluate the applicability of these models to SCC.

    El presente trabajo de investigación tiene como finalidad estudiar la aplicabilidad de los modelos de cálculo del ACI-08, Eurocódigo 2 y de la EHE-08 utilizados para la estimar las propiedades mecánicas del hormigón convencional, en el hormigón autocompactante. Las propiedades mecánicas estudiadas han sido: el módulo de deformación, la resistencia a tracción y la resistencia a flexotracción. Para llevar a cabo la investigación fue necesario construir una extensa base de datos que permitiera albergar en ella una gran cantidad de dosificaciones de hormigón autocompactante y un amplio rango de valores de sus propiedades mecánicas para lograr una muestra lo más representativa posible. En primera instancia se comparó el comportamiento de cada uno de estos modelos normativos de cálculo, con la curva de regresión de los datos obtenidos para el hormig

  10. An Ultradeep Chandra Catalog of X-Ray Point Sources in the Galactic Center Star Cluster

    Science.gov (United States)

    Zhu, Zhenlin; Li, Zhiyuan; Morris, Mark R.

    2018-04-01

    We present an updated catalog of X-ray point sources in the inner 500″ (∼20 pc) of the Galactic center (GC), where the nuclear star cluster (NSC) stands, based on a total of ∼4.5 Ms of Chandra observations taken from 1999 September to 2013 April. This ultradeep data set offers unprecedented sensitivity for detecting X-ray sources in the GC, down to an intrinsic 2–10 keV luminosity of 1.0 × 1031 erg s‑1. A total of 3619 sources are detected in the 2–8 keV band, among which ∼3500 are probable GC sources and ∼1300 are new identifications. The GC sources collectively account for ∼20% of the total 2–8 keV flux from the inner 250″ region where detection sensitivity is the greatest. Taking advantage of this unprecedented sample of faint X-ray sources that primarily traces the old stellar populations in the NSC, we revisit global source properties, including long-term variability, cumulative spectra, luminosity function, and spatial distribution. Based on the equivalent width and relative strength of the iron lines, we suggest that in addition to the arguably predominant population of magnetic cataclysmic variables (CVs), nonmagnetic CVs contribute substantially to the detected sources, especially in the lower-luminosity group. On the other hand, the X-ray sources have a radial distribution closely following the stellar mass distribution in the NSC, but much flatter than that of the known X-ray transients, which are presumably low-mass X-ray binaries (LMXBs) caught in outburst. This, together with the very modest long-term variability of the detected sources, strongly suggests that quiescent LMXBs are a minor (less than a few percent) population.

  11. An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South: Spectroscopic Redshifts

    Science.gov (United States)

    Danielson, A. L. R.; Swinbank, A. M.; Smail, Ian; Simpson, J. M.; Casey, C. M.; Chapman, S. C.; da Cunha, E.; Hodge, J. A.; Walter, F.; Wardlow, J. L.; Alexander, D. M.; Brandt, W. N.; de Breuck, C.; Coppin, K. E. K.; Dannerbauer, H.; Dickinson, M.; Edge, A. C.; Gawiser, E.; Ivison, R. J.; Karim, A.; Kovacs, A.; Lutz, D.; Menten, K.; Schinnerer, E.; Weiß, A.; van der Werf, P.

    2017-05-01

    We present spectroscopic redshifts of {\\text{}}{S}870μ {{m}} ≳ 2 mJy submillimeter galaxies (SMGs), which have been identified from the ALMA follow-up observations of 870 μm detected sources in the Extended Chandra Deep Field South (the ALMA-LESS survey). We derive spectroscopic redshifts for 52 SMGs, with a median of z = 2.4 ± 0.1. However, the distribution features a high-redshift tail, with ˜23% of the SMGs at z≥slant 3. Spectral diagnostics suggest that the SMGs are young starbursts, and the velocity offsets between the nebular emission and UV ISM absorption lines suggest that many are driving winds, with velocity offsets of up to 2000 km s-1. Using the spectroscopic redshifts and the extensive UV-to-radio photometry in this field, we produce optimized spectral energy distributions (SEDs) using Magphys, and use the SEDs to infer a median stellar mass of {M}\\star = (6 ± 1)× 1010 M {}⊙ for our SMGs with spectroscopic redshift. By combining these stellar masses with the star formation rates (measured from the far-infrared SEDs), we show that SMGs (on average) lie a factor of ˜5 above the so-called “main sequence” at z˜ 2. We provide this library of 52 template fits with robust and uniquely well-sampled SEDs as a resource for future studies of SMGs, and also release the spectroscopic catalog of ˜2000 (mostly infrared-selected) galaxies targeted as part of the spectroscopic campaign.

  12. A Search for Optical Counterparts of Chandra Sources in Omega Centauri using ACS

    Science.gov (United States)

    Haggard, D.; Fuller, A. D.; Dorfman, J. L.; Cool, A. M.; Anderson, J.; Edmonds, P. D.; Davies, M. B.

    2002-12-01

    The globular cluster Omega Centauri, with its high mass and large, moderate density core, is of interest both for its population of primordial binaries and for the large number of tidal-capture and/or exchange-collision binaries it may harbor. We have obtained a 3x3 mosaic of Wide Field Camera pointings with HST's Advanced Camera for Surveys, covering a 10'x10' field out to the cluster's half-mass radius. Containing ~1.7 million detected stars, the resulting mosaic represents the most complete image of Omega Cen yet obtained. Here we report preliminary findings of a search in these data for optical counterparts to more than 100 faint X-ray sources (Lx ~ 2 x 1030 - 5 x 1032 erg-s-1) detected in our prior study of Omega Cen using the Chandra X-ray Observatory. Cluster X-ray sources are likely to consist primarily of accreting binary stars and close detached binaries with active coronae. Significant numbers of active galaxies in the background are also expected to be present. Using B, R, and H-alpha images, we are searching for optical counterparts that are H-alpha-bright and blue, as signatures of accretion in cataclysmic variables and/or quiescent low-mass X-ray binaries. Active binaries (e.g., BY Draconis stars) may appear as weaker H-alpha emitters lying on or slightly redward of the main sequence. This work is supported by NASA grant GO-9442 from the Space Telescope Science Institute.

  13. HST/ACS Imaging of Omega Centauri: Optical Counterparts of Chandra X-Ray Sources

    Science.gov (United States)

    Cool, Adrienne M.; Haggard, Daryl; Arias, Tersi; Brochmann, Michelle; Dorfman, Jason; Gafford, April; White, Vivian; Anderson, Jay

    2013-02-01

    We present results of a search for optical counterparts of X-ray sources in and toward the globular cluster Omega Centauri (NGC 5139) using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The ACS data consist of a mosaic of Wide Field Channel images obtained using F625W, F435W, and F658N filters; with nine pointings we cover the central ~10' × 10' of the cluster and encompass 109 known Chandra sources. We find promising optical counterparts for 59 of the sources, ~40 of which are likely to be associated with the cluster. These include 27 candidate cataclysmic variables (CVs), 24 of which are reported here for the first time. Fourteen of the CV candidates are very faint, with absolute magnitudes in the range M 625 =10.4-12.6, making them comparable in brightness to field CVs near the period minimum discovered in the Sloan Digital Sky Survey. Additional optical counterparts include three BY Dra candidates, a possible blue straggler, and a previously reported quiescent low-mass X-ray binary. We also identify 3 foreground stars and 11 probable active galactic nuclei. Finally, we report the discovery of a group of seven stars whose X-ray properties are suggestive of magnetically active binaries, and whose optical counterparts lie on or very near the metal-rich anomalous giant and subgiant branches in ω Cen. If the apparent association between these seven stars and the RGB/SGB-a stars is real, then the frequency of X-ray sources in this metal-rich population is enhanced by a factor of at least five relative to the other giant and subgiant populations in the cluster. If these stars are not members of the metal-rich population, then they bring the total number of red stragglers (also known as sub-subgiants) that have been identified in ω to Cen 20, the largest number yet known in any globular cluster.

  14. Chandra High-Resolution X-Ray Spectroscopy of AM Herculis

    Science.gov (United States)

    Girish, V.; Rana, V. R.; Singh, K. P.

    2007-03-01

    We present the results of high-resolution spectroscopy of the prototype Polar AM Herculis observed with Chandra High Energy Transmission Grating . The X-ray spectrum contains hydrogen-like and helium-like lines of Fe, S, Si, Mg, Ne, and O, with several Fe L-shell emission lines. The forbidden lines in the spectrum are generally weak, whereas the hydrogen-like lines are stronger suggesting that emission from a multitemperature, collisionally ionized plasma dominates. The helium-like line flux ratios yield a plasma temperature of 2 MK and a plasma density 1-9×1012 cm-3, whereas the line flux ratio of Fe XXVI to Fe XXV gives an ionization temperature of 12.4+1.1-1.4 keV. We present the differential emission measure distribution of AM Her, whose shape is consistent with the volume emission measure obtained by a multitemperature APEC model. The multitemperature plasma model fit to the average X-ray spectrum indicates the mass of the white dwarf to be ~1.15 Msolar. From phase-resolved spectroscopy, we find the line centers of Mg XII, S XVI, resonance line of Fe XXV, and Fe XXVI emission modulated by a few hundred to 1000 km s-1 from the theoretically expected values, indicating bulk motion of ionized matter in the accretion column of AM Her. The observed velocities of Fe XXVI ions are close to the expected shock velocity for a 0.6 Msolar white dwarf. The observed velocity modulation is consistent with that expected from a single pole accreting binary system.

  15. CHANDRA DETECTION OF X-RAY EMISSION FROM ULTRACOMPACT DWARF GALAXIES AND EXTENDED STAR CLUSTERS

    International Nuclear Information System (INIS)

    Hou, Meicun; Li, Zhiyuan

    2016-01-01

    We have conducted a systematic study of X-ray emission from ultracompact dwarf (UCD) galaxies and extended star clusters (ESCs), based on archival Chandra observations. Among a sample of 511 UCDs and ESCs complied from the literature, 17 X-ray counterparts with 0.5–8 keV luminosities above ∼5 × 10 36 erg s −1 are identified, which are distributed in eight early-type host galaxies. To facilitate comparison, we also identify X-ray counterparts of 360 globular clusters (GCs) distributed in four of the eight galaxies. The X-ray properties of the UCDs and ESCs are found to be broadly similar to those of the GCs. The incidence rate of X-ray-detected UCDs and ESCs, 3.3% ± 0.8%, while lower than that of the X-ray-detected GCs (7.0% ± 0.4%), is substantially higher than expected from the field populations of external galaxies. A stacking analysis of the individually undetected UCDs/ESCs further reveals significant X-ray signals, which corresponds to an equivalent 0.5–8 keV luminosity of ∼4 × 10 35 erg s −1 per source. Taken together, these provide strong evidence that the X-ray emission from UCDs and ESCs is dominated by low-mass X-ray binaries having formed from stellar dynamical interactions, consistent with the stellar populations in these dense systems being predominantly old. For the most massive UCDs, there remains the possibility that a putative central massive black hole gives rise to the observed X-ray emission

  16. Variability-selected active galactic nuclei from supernova search in the Chandra deep field south

    Science.gov (United States)

    Trevese, D.; Boutsia, K.; Vagnetti, F.; Cappellaro, E.; Puccetti, S.

    2008-09-01

    Context: Variability is a property shared by virtually all active galactic nuclei (AGNs), and was adopted as a criterion for their selection using data from multi epoch surveys. Low Luminosity AGNs (LLAGNs) are contaminated by the light of their host galaxies, and cannot therefore be detected by the usual colour techniques. For this reason, their evolution in cosmic time is poorly known. Consistency with the evolution derived from X-ray detected samples has not been clearly established so far, also because the low luminosity population consists of a mixture of different object types. LLAGNs can be detected by the nuclear optical variability of extended objects. Aims: Several variability surveys have been, or are being, conducted for the detection of supernovae (SNe). We propose to re-analyse these SNe data using a variability criterion optimised for AGN detection, to select a new AGN sample and study its properties. Methods: We analysed images acquired with the wide field imager at the 2.2 m ESO/MPI telescope, in the framework of the STRESS supernova survey. We selected the AXAF field centred on the Chandra Deep Field South where, besides the deep X-ray survey, various optical data exist, originating in the EIS and COMBO-17 photometric surveys and the spectroscopic database of GOODS. Results: We obtained a catalogue of 132 variable AGN candidates. Several of the candidates are X-ray sources. We compare our results with an HST variability study of X-ray and IR detected AGNs, finding consistent results. The relatively high fraction of confirmed AGNs in our sample (60%) allowed us to extract a list of reliable AGN candidates for spectroscopic follow-up observations. Table [see full text] is only available in electronic form at http://www.aanda.org

  17. The Theoretical Analysis of the Definition of «Financial Investments» and Harmonization of the Accounting and Auditing System in Accordance with the IFRS and the ACI

    Directory of Open Access Journals (Sweden)

    Koliesnichenko Anastasiia S.

    2017-11-01

    Full Text Available The article systematizes the existing views on the category of «Financial Investments» (FI and substantiates that the ideology of financial investment be disclosed by determining the degree of regulation of this concept. In accordance with both normative and scientific approaches a matrix of the terminological essence of definition of FI was constructed, on the basis of which three fundamental components were allocated: object-static, dynamic, and target. Elements of the concept of «financial investments» had been structured and a component analysis was carried out, which became the basis for constructing the logic of interpretation of this economic category with the purpose of leveling theoretical differences in the interpretation of financial assets in terms of harmonizing their accounting with the IFRS and the ACI. It has been substantiated that there is a transition to the more developed theoretical level of perception of FI, which is expressed in the interpenetration of economic and legal branches of knowledge in the context of interpretation of this scientific category while positioning investment processes in the international coordinate system.

  18. La imagen proyectada por la Bética costera durante los siglos II a.C. a I d.C. : un análisis iconológico de su acuñación monetal

    Directory of Open Access Journals (Sweden)

    Elena Moreno Pulido

    2008-01-01

    Full Text Available Este trabajo tiene como objetivo el estudio de la iconografía monetaria de las cecas marítimas de la Bética, desde los inicios de su acuñación hasta el cierre de las mismas. El análisis sincrónico, iconográfico e iconológico conjunto de su numerario muestra las conexiones económicas y culturales entre estas ciudades, a la vez que presenta visualmente el avance de la romanización, así como la integración de estas comunidades, tradicionalmente púnicas, en la cultura latinaThis work takes as a target the study of the monetary iconography of the marine mints of the Baetica, from the beginnings of his coinage up to the closing of the same ones. The synchronous iconographic and iconologic analysis of his money shows the economic and cultural connections between these cities, simultaneously it presents visually the advance of the roman civilization, as well as the integration of these communities, phoenician traditionally, in the Latin culture.

  19. Searching for the 3.5 keV Line in the Deep Fields with Chandra: The 10 Ms Observations

    Science.gov (United States)

    Cappelluti, Nico; Bulbul, Esra; Foster, Adam; Natarajan, Priyamvada; Urry, Megan C.; Bautz, Mark W.; Civano, Francesca; Miller, Eric; Smith, Randall K.

    2018-02-01

    We report a systematic search for an emission line around 3.5 keV in the spectrum of the cosmic X-ray background using a total of ∼10 Ms Chandra observations toward the COSMOS Legacy and Extended Chandra Deep Field South survey fields. We find marginal evidence of a feature at an energy of ∼3.51 keV with a significance of 2.5–3σ, depending on the choice of statistical treatment. The line intensity is best fit at (8.8 ± 2.9) × 10‑7 ph cm‑2 s‑1 when using a simple Δχ 2 or {10.2}-0.4+0.2× {10}-7 ph cm‑2 s‑1 when Markov chain Monte Carlo is used. Based on our knowledge of Chandra and the reported detection of the line by other instruments, an instrumental origin for the line remains unlikely. We cannot, however, rule out a statistical fluctuation, and in that case our results provide a 3σ upper limit at 1.85 × 10‑6 ph cm‑2 s‑1. We discuss the interpretation of this observed line in terms of the iron line background, S XVI charge exchange, as well as potentially being from sterile neutrino decay. We note that our detection is consistent with previous measurements of this line toward the Galactic center and can be modeled as the result of sterile neutrino decay from the Milky Way for the dark matter distribution modeled as a Navarro–Frenk–White profile. For this case, we estimate a mass m ν ∼ 7.01 keV and a mixing angle sin2(2θ) = (0.83–2.75) × 10‑10. These derived values are in agreement with independent estimates from galaxy clusters, the Galactic center, and M31.

  20. Catching an FUor in the Act: Chandra ToO Observations of Extreme Accretion onto Young S

    Science.gov (United States)

    Pooley, David

    2017-09-01

    FU Orionis (FUor) outbursts are a transitory rapid accretion phase in the evolution of young stellar objects. We propose to obtain an X-ray observation during the rise to peak optical brightness of an FUor with Chandra, as well as two additional follow-up observations after the optical peak. The early, pre-peak phase has only been observed once before in X-rays (by this team). Following the X-ray behavior of an FUor object through the initial rise and later evolution will reveal important information about the nature and source of the outburst trigger mechanism in these objects.

  1. X-ray properties of the z ~ 4.5 Lyman-alpha Emitters in the Chandra Deep Field South Region

    OpenAIRE

    Zheng, Z. Y.; Wang, J. X.; Finkelstein, S. L.; Malhotra, S.; Rhoads, J. E.; Finkelstein, K. D.

    2010-01-01

    We report the first X-ray detection of 113 Lyman-alpha emitters at redshift z ~ 4.5. Only one source (J033127.2-274247) is detected in the Extended Chandra Deep Field South (ECDF-S) X-ray data, and has been spectroscopically confirmed as a z = 4.48 quasar with $L_X = 4.2\\times 10^{44}$ erg/s. The single detection gives a Lyman-alpha quasar density consistent with the X-ray luminosity function of quasars. The coadded counts of 22 Lyman-alpha emitters (LAEs) in the central Chandra Deep Field So...

  2. HST/ACS IMAGING OF OMEGA CENTAURI: OPTICAL COUNTERPARTS OF CHANDRA X-RAY SOURCES

    International Nuclear Information System (INIS)

    Cool, Adrienne M.; Arias, Tersi; Brochmann, Michelle; Dorfman, Jason; Gafford, April; White, Vivian; Haggard, Daryl; Anderson, Jay

    2013-01-01

    We present results of a search for optical counterparts of X-ray sources in and toward the globular cluster Omega Centauri (NGC 5139) using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The ACS data consist of a mosaic of Wide Field Channel images obtained using F625W, F435W, and F658N filters; with nine pointings we cover the central ∼10' × 10' of the cluster and encompass 109 known Chandra sources. We find promising optical counterparts for 59 of the sources, ∼40 of which are likely to be associated with the cluster. These include 27 candidate cataclysmic variables (CVs), 24 of which are reported here for the first time. Fourteen of the CV candidates are very faint, with absolute magnitudes in the range M 625 =10.4-12.6, making them comparable in brightness to field CVs near the period minimum discovered in the Sloan Digital Sky Survey. Additional optical counterparts include three BY Dra candidates, a possible blue straggler, and a previously reported quiescent low-mass X-ray binary. We also identify 3 foreground stars and 11 probable active galactic nuclei. Finally, we report the discovery of a group of seven stars whose X-ray properties are suggestive of magnetically active binaries, and whose optical counterparts lie on or very near the metal-rich anomalous giant and subgiant branches in ω Cen. If the apparent association between these seven stars and the RGB/SGB-a stars is real, then the frequency of X-ray sources in this metal-rich population is enhanced by a factor of at least five relative to the other giant and subgiant populations in the cluster. If these stars are not members of the metal-rich population, then they bring the total number of red stragglers (also known as sub-subgiants) that have been identified in ω to Cen 20, the largest number yet known in any globular cluster.

  3. Clusters, groups, and filaments in the Chandra deep field-south up to redshift 1

    International Nuclear Information System (INIS)

    Dehghan, S.; Johnston-Hollitt, M.

    2014-01-01

    We present a comprehensive structure detection analysis of the 0.3 deg 2 area of the MUSYC-ACES field, which covers the Chandra Deep Field-South (CDFS). Using a density-based clustering algorithm on the MUSYC and ACES photometric and spectroscopic catalogs, we find 62 overdense regions up to redshifts of 1, including clusters, groups, and filaments. We also present the detection of a relatively small void of ∼10 Mpc 2 at z ∼ 0.53. All structures are confirmed using the DBSCAN method, including the detection of nine structures previously reported in the literature. We present a catalog of all structures present, including their central position, mean redshift, velocity dispersions, and classification based on their morphological and spectroscopic distributions. In particular, we find 13 galaxy clusters and 6 large groups/small clusters. Comparison of these massive structures with published XMM-Newton imaging (where available) shows that 80% of these structures are associated with diffuse, soft-band (0.4-1 keV) X-ray emission, including 90% of all objects classified as clusters. The presence of soft-band X-ray emission in these massive structures (M 200 ≥ 4.9 × 10 13 M ☉ ) provides a strong independent confirmation of our methodology and classification scheme. In the closest two clusters identified (z < 0.13) high-quality optical imaging from the Deep2c field of the Garching-Bonn Deep Survey reveals the cD galaxies and demonstrates that they sit at the center of the detected X-ray emission. Nearly 60% of the clusters, groups, and filaments are detected in the known enhanced density regions of the CDFS at z ≅ 0.13, 0.52, 0.68, and 0.73. Additionally, all of the clusters, bar the most distant, are found in these overdense redshift regions. Many of the clusters and groups exhibit signs of ongoing formation seen in their velocity distributions, position within the detected cosmic web, and in one case through the presence of tidally disrupted central galaxies

  4. CHANDRA PHASE-RESOLVED X-RAY SPECTROSCOPY OF THE CRAB PULSAR

    International Nuclear Information System (INIS)

    Weisskopf, Martin C.; Tennant, Allyn F.; O'Dell, Stephen L.; Elsner, Ronald F.; Yakovlev, Dmitry G.; Harding, Alice; Zavlin, Vyacheslav E.; Becker, Werner

    2011-01-01

    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 underabundant in oxygen and provide measurements with improved accuracy and less bias. Using the abundances and cross sections from Wilms et al. we find [O/H] = (5.28 ± 0.28) × 10 –4 (4.9 × 10 –4 is solar abundance). We also measure for the first time the impact of scattering of flux out of the image by interstellar grains. We find τ 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 also 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 are 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. We discuss how such data are best connected to theoretical models of neutron star cooling and neutron star interiors. The data restrict the neutrino emission rate in the pulsar core and the amount of light elements in the heat-blanketing envelope. The observations allow the

  5. Where Are the r-modes? Chandra Observations of Millisecond Pulsars

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoodifar, Simin; Strohmayer, Tod [Astrophysics Science Division and Joint Space-Science Institute, NASA' s Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2017-05-10

    We present the results of Chandra observations of two non-accreting millisecond pulsars, PSRs J1640+2224 (J1640) and J1709+2313 (J1709), with low inferred magnetic fields and spin-down rates in order to constrain their surface temperatures, obtain limits on the amplitude of unstable r -modes in them, and make comparisons with similar limits obtained for a sample of accreting low-mass X-ray binary (LMXB) neutron stars. We detect both pulsars in the X-ray band for the first time. They are faint, with inferred soft X-ray fluxes (0.3–3 keV) of ≈6 × 10{sup −15} and 3 × 10{sup −15} erg cm{sup −2} s{sup −1} for J1640 and J1709, respectively. Spectral analysis assuming hydrogen atmosphere emission gives global effective temperature upper limits (90% confidence) of 3.3–4.3 × 10{sup 5} K for J1640 and 3.6–4.7 × 10{sup 5} K for J1709, where the low end of the range corresponds to canonical neutron stars ( M = 1.4 M {sub ⊙}), and the upper end corresponds to higher-mass stars ( M = 2.21 M {sub ⊙}). Under the assumption that r -mode heating provides the thermal support, we obtain dimensionless r -mode amplitude upper limits of 3.2–4.8 × 10{sup −8} and 1.8–2.8 × 10{sup −7} for J1640 and J1709, respectively, where again the low end of the range corresponds to lower-mass, canonical neutron stars ( M = 1.4 M {sub ⊙}). These limits are about an order of magnitude lower than those we derived previously for a sample of LMXBs, except for the accreting millisecond X-ray pulsar SAX J1808.4–3658, which has a comparable amplitude limit to J1640 and J1709.

  6. Preliminary Results from a Coordinated Hisaki/Chandra/XMM-Newton Study of the Jovian Aurora and Io Plasma Torus

    Science.gov (United States)

    Kraft, Ralph; Kimura, Tomoki; Elsner, Ronald; Branduardi-Raymont, Graziella; Gladstone, Randy; Badman, Sarah Victoria; Ezoe, Yuichiro; Murakami, Go; Murray, Stephen S.; Roediger, Elke; hide

    2014-01-01

    We present preliminary results from a coordinated Hisaki/Chandra/XMM-Newton observational campaign of the Jovian aurora and Io plasma torus. The data were taken over a three week period in April, 2014. Jupiter was observed continuously with Hisaki, six times with the Chandra/HRC instrument for roughly 12 hours per observation, and twice by XMM-Newton. The goal of this observational campaign was to understand how energy and matter are exchanged between the Jovian aurora, the IPT, and the Solar wind. X-ray observations provide key diagnostics on highly stripped ions and keV electrons in the Jovian magnetosphere. We use the temporal, spatial, and spectral capabilities of the three instruments to search for correlated variability between the Solar wind, the EUV-emitting plasma of the IPT and UV aurora, and the ions responsible for the X-ray aurora. Preliminary analysis suggests a strong 45 min periodicity in the EUV emission from the electron aurora. There is some evidence for complex variability of the X-ray auroras on scales of tens of minutes. There is also clear morphological changes in the X-ray aurora that do not appear to be correlated with either variations in the IPT or Solar wind.

  7. Buried Black Hole Growth in Advanced Mergers: The Discovery of a Large Population of Dual AGN Candidates by Chandra

    Science.gov (United States)

    Satyapal, Shobita; Secrest, Nathan; Ellison, Sara L.; Ricci, Claudio; Pfeifle, Ryan William; Blecha, Laura; Rothberg, Barry; Gliozzi, Mario; Constantin, Anca; Ferguson, Jason

    2018-01-01

    Interactions between galaxies are predicted to cause gas inflows that can potentially trigger nuclear activity. Since the inflowing material can obscure the central regions of interacting galaxies, a potential limitation of previous optical studies is that obscured active galactic nuclei (AGNs) can be missed at various stages along the merger sequence. In a recent large mid-infrared study of AGNs in mergers, we demonstrated that the fraction of obscured AGNs increases with merger stage, with the most energetically dominant optically obscured AGNs becoming more prevalent in the most advanced mergers, consistent with theoretical predictions. In a recent Chandra program, we discovered 8 out of 15 infrared-selected advanced mergers that display two nuclear X-ray sources with separations of a few kiloparsecs consistent with highly absorbed dual AGNs, demonstrating that WISE pre-selection may be effective in identifying a new population of optically invisible dual AGNs. These observations reveal that infrared and X-ray observations are critical in uncovering the most efficient environments for supermassive black hole accretion and a key stage in galaxy evolution. In this talk, I will discuss Chandra, NuSTAR, and near-infrared spectroscopic observations of these dual AGN candidates and recent hydrodynamic simulations that predict that this key stage in galaxy evolution is expected to be highly obscured.

  8. A CHANDRA SNAPSHOT SURVEY FOR 3C RADIO GALAXIES WITH REDSHIFTS BETWEEN 0.3 AND 0.5

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F. [SLAC National Laboratory and Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Harris, D. E.; Paggi, A. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Tremblay, G. R. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Muenchen (Germany); Liuzzo, E. [Istituto di Radioastronomia, INAF, via Gobetti 101, I-40129, Bologna (Italy); Bonafede, A. [Hamburger Sternwarte, Universitaet Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany)

    2013-05-01

    This paper contains an analysis of short Chandra observations of 19 3C sources with redshifts between 0.3 and 0.5 not previously observed in the X-rays. This sample is part of a project to obtain Chandra data for all of the extragalactic sources in the 3C catalog. Nuclear X-ray intensities as well as any X-ray emission associated with radio jet knots, hotspots, or lobes have been measured in three energy bands: soft, medium, and hard. Standard X-ray spectral analysis for the four brightest nuclei has also been performed. X-ray emission was detected for all the nuclei of the radio sources in the current sample with the exception of 3C 435A. There is one compact steep spectrum source while all the others are FR II radio galaxies. X-ray emission from two galaxy clusters (3C 19 and 3C 320), from six hotspots in four radio galaxies (3C 16, 3C 19, 3C 268.2, 3C 313), and extended X-ray emission on kiloparsec scales in 3C 187 and 3C 313, has been detected.

  9. Comparative Analysis and Variability of the Jovian X-Ray Spectra Detected by the Chandra and XMM-Newton Observatories

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Yawei [ORNL; Schultz, David Robert [ORNL; Kharchenko, Vasili A [ORNL; Bhardwaj, Anil [Vikram Sarabhai Space Center, Trivandrum, India; Branduardi-Raymont, Graziella [University College, London; Stancil, Phillip C. [University of Georgia, Athens, GA; Cravens, Thomas E. E. [University of Kansas; Lisse, Carey M. [Johns Hopkins University; Dalgarno, A. [Harvard-Smithsonian Center for Astrophysics

    2010-01-01

    Expanding upon recent work, a more comprehensive spectral model based on charge exchange induced X-ray emission by ions precipitating into the Jovian atmosphere is used to provide new understanding of the polar auroras. In conjunction with the Xspec spectral fitting software, the model is applied to analyze observations from both Chandra and XMM-Newton by systematically varying the initial precipitating ion parameters to obtain the best fit model for the observed spectra. In addition to the oxygen and sulfur ions considered previously, carbon is included to discriminate between solar wind and Jovian magnetospheric ion origins, enabled by the use of extensive databases of both atomic collision cross sections and radiative transitions. On the basis of fits to all the Chandra observations, we find that carbon contributes negligibly to the observed polar X-ray emission suggesting that the highly accelerated precipitating ions are of magnetospheric origin. Most of the XMM-Newton fits also favor this conclusion with one exception that implies a possible carbon contribution. Comparison among all the spectra from these two observatories in light of the inferred initial energies and relative abundances of precipitating ions from the modeling show that they are significantly variable in time (observation date) and space (north and south polar X-ray auroras).

  10. The 3 Megasecond Chandra Campaign on Sgr A*: A Census of X-ray Flaring Activity from the Galactic Center

    Science.gov (United States)

    Neilsen, Joseph; Nowak, Michael; Gammie, Charles F.; Dexter, Jason; Markoff, Sera; Haggard, Daryl; Nayakshin, Sergei; Wang, Q. Daniel; Grosso, N.; Porquet, D.; Tomsick, John; Degenaar, Nathalie; Fragile, P. Christopher; Houck, John C.; Wijnands, Rudy; Miller, Jon M.; Baganoff, Frederick K.

    2014-08-01

    Over the last decade, X-ray observations of Sgr A* have revealed a black hole in a deep sleep, punctuated roughly once per day by brief ares. The extreme X-ray faintness of this supermassive black hole has been a long-standing puzzle in black hole accretion. To study the accretion processes in the Galactic Center, Chandra (in concert with numerous ground- and space-based observatories) undertook a 3 Ms campaign on Sgr A* in 2012. With its excellent observing cadence, sensitivity, and spectral resolution, this Chandra X-ray Visionary Project (XVP) provides an unprecedented opportunity to study the behavior of our closest supermassive black hole. We present a progress report from our ongoing study of X-ray flares, including one of the brightest flares ever seen from Sgr A*. Focusing on the statistics of the flares, the quiescent emission, and the relationship between the X-ray and the infrared, we discuss the physical implications of X-ray variability in the Galactic Center.

  11. Simultaneous NuSTAR/Chandra Observations of The Bursting Pulsar GRO J1744-28 During Its Third Reactivation

    DEFF Research Database (Denmark)

    Younes, G.; Kouveliotou, C.; Grefenstette, B. W.

    2015-01-01

    constant. The 0.5-70 keV spectra of the persistent and dip emission are the same within errors and well described by a blackbody (BB), a power-law (PL) with an exponential rolloff, a 10 keV feature, and a 6.7 keV emission feature, all modified by neutral absorption. Assuming that the BB emission originates...... keV with an Eddington persistent flux level. Seven bursts, followed by dips, are seen with Chandra, three of which are also detected with NuSTAR. Timing analysis reveals a slight increase in the persistent emission pulsed fraction with energy (from 10% to 15%) up to 10 keV, above which it remains...... in an accretion disk, we estimate its inner (magnetospheric) radius to be about 4 × 107 cm, which translates to a surface dipole field B ≈ 9 × 1010 G. The Chandra/HETG spectrum resolves the 6.7 keV feature into (quasi-)neutral and highly ionized Fe xxv and Fe xxvi emission lines. XSTAR modeling shows these lines...

  12. La acies de la Aulularia plautina

    Directory of Open Access Journals (Sweden)

    José Castañé Llinás

    1989-06-01

    Full Text Available Plautus frequently reflects on the social and political structures of Roman life. Consequently, many passages in his palliatae are found to reveal his love of the Roman army, because during his time, spectators liked very much to see soldiers on the scene and to listen to military language. So, Plautus’ concern with the army —soldiers, arms, salaries, military tactics, etc.— is apparent throughout his comical plays. Our aim in this paper is to demonstrate how Plautus satirizes that vice of rich Roman married women —to spend a great deal of money on clothes, shoes, etc.— in a military way. At the same time, an attempt is made to arrive at a method of study of Plautus’ plays that determines the real meaning of his words.

  13. Chandra observations of comet 2P/Encke 2003 : First detection of a collisionally thin, fast solar wind charge exchange system

    NARCIS (Netherlands)

    Lisse, CM; Christian, DJ; Dennerl, K; Wolk, SJ; Bodewits, Dennis; Hoekstra, Ronnie; Combi, MR; Makinen, T; Dryer, M; Fry, CD; Weaver, H

    2005-01-01

    We report the results of 15 hr of Chandra observations of comet 2P/Encke 2003 on November 24. X-ray emission from comet Encke was resolved on scales of 500-40,000 km, with unusual morphology due to the presence of a low-density, collisionally thin (to charge exchange) coma. A light curve with

  14. Assessing the status of glaciers in part of the Chandra basin, Himachal Himalaya: A multiparametric approach

    Science.gov (United States)

    Garg, Purushottam Kumar; Shukla, Aparna; Tiwari, Reet Kamal; Jasrotia, Avtar Singh

    2017-05-01

    This study investigates the change in multiple glacier parameters of three valley-type glaciers (Sakchum (SC), Chhota Shigri (CS), and Bara Shigri (BS)) located in Chandra basin, Himachal Himalaya, sharing the same climatic regime, and assesses the control of nonclimatic factors on wholesome glacier response. Multitemporal satellite remote sensing data from Landsat-TM/ETM/OLI (1993-2014), and Terra-ASTER (2002-2014) along with an SRTM digital elevation model were used for extraction of the glacier parameters. Results show that while SC and BS retreated (SC: 10.65 ± 2.52 m/y; BS: 15.51 ± 2.52 m/y) and lost area (SC: 0.49 ± 0.0032 km2, BS: 1.18 ± 0.0032 km2), the CS remained relatively stable (retreat rate: 4.06 ± 2.52 m/y, area loss: 0.19 ± 0.0032 km2) during 1993-2014. However, results of surface ice velocities (SIV) change (SC: 24.41%, CS: 21.60%, and BS: 28.49%) and surface elevation change (SC: - 1.22 m/y, CS: - 0.91 m/y and BS: - 1.21 m/y) suggest a comparable slowing down and surface lowering from 2002 to 2014. Debris cover also varied substantially (SC: 30.25%, CS: 11.96%, BS: 19.61%) on these glaciers. Results reveal that higher retreat/deglaciation of glaciers was associated with higher altitudinal range, slow SIV in lower ablation zones (LAZ), and glacier hypsometry. Debris cover on glaciers was found to be controlled by slope, higher deglaciation rates, higher SIV in the upper ablation zone (UAZ) coupled with lower SIV in LAZ and surface lowering. Glacier SIV was primarily governed by slope gradient, differential surface lowering, and size of accumulation zone (ACZ). The SIV results confirm the presence of stagnant zones in the lower ablations of SC (changing spatial distribution of debris cover, presence of supraglacial lakes, and ice cliffs bordering them. Melting around supraglacial lakes and backwasting of ice cliffs may be the prime reasons behind intense mass loss observed in the stagnant zone of the Bara Shigri glacier, where surface lowering

  15. Contributions of the "Great" X-Ray Observatories (XMM-Newton and Chandra) to Astronomy and Astrophysics

    Science.gov (United States)

    Weisskopf, Martin

    2011-01-01

    NASA s Chandra X-ray Observatory and ESA s XMM-Newton made their first observations over a decade ago. The unprecedented and complementary capabilities of these observatories to detect, image, and measure the energy of cosmic X-rays, achieved less than 50 years after the first detection of an extra-solar X-ray source, represent an increase in sensitivity comparable in going from naked-eye observations to the most powerful optical telescopes over the past 400 years. In this presentation we highlight some of the many discoveries made using these powerful X-ray observatories that have transformed 21st century astronomy. We briefly discuss future prospects for this truly exciting field.

  16. VizieR Online Data Catalog: Type 2 AGN host galaxies in Chandra-COSMOS (Suh+, 2017)

    Science.gov (United States)

    Suh, H.; Civano, F.; Hasinger, G.; Lusso, E.; Lanzuisi, G.; Marchesi, S.; Trakhtenbrot, B.; Allevato, V.; Cappelluti, N.; Capak, P. L.; Elvis, M.; Griffiths, R. E.; Laigle, C.; Lira, P.; Riguccini, L.; Rosario, D. J.; Salvato, M.; Schawinski, K.; Vignali, C.

    2018-01-01

    We investigate the star formation properties of a large sample of ~2300 X-ray-selected Type 2 Active Galactic Nuclei (AGNs) host galaxies out to z~3 in the Chandra COSMOS Legacy Survey in order to understand the connection between the star formation and nuclear activity. Making use of the existing multi-wavelength photometric data available in the COSMOS field, we perform a multi-component modeling from far-infrared to near-ultraviolet using a nuclear dust torus model, a stellar population model and a starburst model of the spectral energy distributions (SEDs). Through detailed analyses of SEDs, we derive the stellar masses and the star formation rates (SFRs) of Type 2 AGN host galaxies. The stellar mass of our sample is in the range of 93), and grow slowly through secular fueling processes hosting moderate-luminosity AGNs. (1 data file).

  17. A Joint Chandra and Swift View of the 2015 X-ray Dust-scattering Echo of V404 Cygni

    Science.gov (United States)

    Heinz, S.; Corrales, L.; Smith, R.; Brandt, W. N.; Jonker, P. G.; Plotkin, R. M.; Neilsen, J.

    2016-07-01

    We present a combined analysis of the Chandra and Swift observations of the 2015 X-ray echo of V404 Cygni. Using a stacking analysis, we identify eight separate rings in the echo. We reconstruct the soft X-ray light curve of the 2015 June outburst using the high-resolution Chandra images and cross-correlations of the radial intensity profiles, indicating that about 70% of the outburst fluence occurred during the bright flare at the end of the outburst on MJD 57199.8. By deconvolving the intensity profiles with the reconstructed outburst light curve, we show that the rings correspond to eight separate dust concentrations with precise distance determinations. We further show that the column density of the clouds varies significantly across the field of view, with the centroid of most of the clouds shifted toward the Galactic plane, relative to the position of V404 Cyg, invalidating the assumption of uniform cloud column typically made in attempts to constrain dust properties from light echoes. We present a new XSPEC spectral dust-scattering model that calculates the differential dust-scattering cross section for a range of commonly used dust distributions and compositions and use it to jointly fit the entire set of Swift echo data. We find that a standard Mathis-Rumpl-Nordsieck model provides an adequate fit to the ensemble of echo data. The fit is improved by allowing steeper dust distributions, and models with simple silicate and graphite grains are preferred over models with more complex composition.

  18. Large-format, high-speed, X-ray pnCCDs combined with electron and ion imaging spectrometers in a multipurpose chamber for experiments at 4th generation light sources

    Energy Technology Data Exchange (ETDEWEB)

    Strueder, Lothar [Max Planck Advanced Study Group, Center for Free Electron Laser Science (CFEL), Notkestr. 85, D-22607 Hamburg (Germany); Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85741 Garching (Germany); MPI Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Muenchen (Germany); University of Siegen, Emmy-Noether Campus, Walter Flex Str. 3, D-57068 Siegen (Germany); Epp, Sascha; Rolles, Daniel [Max Planck Advanced Study Group, Center for Free Electron Laser Science (CFEL), Notkestr. 85, D-22607 Hamburg (Germany); Hartmann, Robert; Holl, Peter; Lutz, Gerhard; Soltau, Heike; Eckart, Rouven; Reich, Christian; Heinzinger, Klaus; Thamm, Christian [PNSensor GmbH, Roemerstrasse 28, D-80803 Muenchen (Germany); MPI Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Muenchen (Germany); Rudenko, Artem; Krasniqi, Faton [Max Planck Advanced Study Group, Center for Free Electron Laser Science (CFEL), Notkestr. 85, D-22607 Hamburg (Germany); Kuehnel, Kai-Uwe; Bauer, Christian; Schroeter, Claus-Dieter [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Moshammer, Robert [Max Planck Advanced Study Group, Center for Free Electron Laser Science (CFEL), Notkestr. 85, D-22607 Hamburg (Germany); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Techert, Simone [Max Planck Advanced Study Group, Center for Free Electron Laser Science (CFEL), Notkestr. 85, D-22607 Hamburg (Germany); Max-Planck-Institut fuer biophysikalische Chemie, Am Fassberg 11, 37077 Goettingen (Germany); Miessner, Danilo; Porro, Matteo [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85741 Garching (Germany); MPI Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Muenchen (Germany)

    2010-03-11

    Fourth generation accelerator-based light sources, such as VUV and X-ray Free Electron Lasers (FEL), deliver ultra-brilliant (approx10{sup 12}-10{sup 13} photons per bunch) coherent radiation in femtosecond (approx10-100 fs) pulses and, thus, require novel focal plane instrumentation in order to fully exploit their unique capabilities. As an additional challenge for detection devices, existing (FLASH, Hamburg) and future FELs (LCLS, Menlo Park; SCSS, Hyogo and the European XFEL, Hamburg) cover a broad range of photon energies from the EUV to the X-ray regime with significantly different bandwidths and pulse structures reaching up to MHz micro-bunch repetition rates. Moreover, hundreds up to trillions of fragment particles, ions, electrons or scattered photons can emerge when a single light flash impinges on matter with intensities up to 10{sup 22} W/cm{sup 2}. In order to meet these challenges, the Max Planck Advanced Study Group (ASG) within the Center for Free Electron Laser Science (CFEL) has designed the CFEL-ASG MultiPurpose (CAMP) chamber. It is equipped with specially developed photon and charged particle detection devices dedicated to cover large solid-angles. A variety of different targets are supported, such as atomic, (aligned) molecular and cluster jets, particle injectors for bio-samples or fixed target arrangements. CAMP houses 4pi solid-angle ion and electron momentum imaging spectrometers ('reaction microscope', REMI, or 'velocity map imaging', VMI) in a unique combination with novel, large-area, broadband (50 eV-25 keV), high-dynamic-range, single-photon-counting and imaging X-ray detectors based on the pnCCDs. This instrumentation allows a new class of coherent diffraction experiments in which both electron and ion emission from the target may be simultaneously monitored. This permits the investigation of dynamic processes in this new regime of ultra-intense, high-energy radiation-matter interaction. After an introduction into

  19. Chandra Snapshot Spectral Imaging of Comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR)

    Science.gov (United States)

    Lisse, Carey

    2003-09-01

    The highly favorable perigee passage of the very bright comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) in late May 2004 provides an opportunity to study cometary x-ray emission in conjunction with the new CHIPS spectroscopic mission. In 10 ksec of on-target time for each comet, ACIS-S will obtain snapshot images of the comets in the heart of the CHIPS 0.05 0.150 keV spectroscopic monitoring period in late-May 2004. The combined observations have the potential of directly detecting for the first time the ultra-soft emission due to Mg, S, Si, and Fe predicted by McCammon et al. (2002) from soft x-ray background measurements and by Kharchenko et al. (2000, 2003) from models of solar wind minor ion charge exchange emission. New work by Wegmann, Dennerl, and Lisse (2004) allows a determination of the neutral gas production rate from the spatial scale of the emission, and an independent determination of the solar wind minor ion flux density using the x-ray surface brightness.

  20. Un outil pour la valorisation des laitiers d’aciérie de conversion en techniques routières A tool for BOF Slag’s valorisation in roads

    Directory of Open Access Journals (Sweden)

    Dao P-L.

    2012-09-01

    Full Text Available Les laitiers d’aciérie de conversion (LAC sont les résidus de la transformation de la fonte en acier. Ces produits abondants (plus de 2 millions de tonnes/an en France sont peu valorisés en génie civil car ils contiennent de la chaux libre qui, en s’hydratant, cause des expansions souvent conséquentes. Un outil pour leur utilisation dans les mélanges granulaires routiers a été développé. Il est basé sur deux modèles paramétriques décrivant, l’un le taux de grains dégradés en milieu aqueux à température et à âge donnés en fonction de la teneur en chaux libre, de la taille et de la structure des grains, l’autre l’expansion volumique d’empilements granulaires, purs ou mélangés à des granulats inertes, soumis à un flux de vapeur. La combinaison de ces deux modèles avec le Modèle d’Empilement Compressible du LCPC permet alors de prédire la cinétique de l’expansion d’un mélange granulaire quelconque, et de désigner des mélanges optimisés en termes de granularité et de proportions, incorporant des LAC, pour un usage spécifié par une expansion tolérée à une échéance et dans un environnement donnés. BOF Slags are residues of the transformation of melting steel. These abundant products (more than 2 million tonnes per year in France are little valued in civil engineering because they contain free lime which, by hydrating, cause often substantial expansions. A tool for use in road granular mixtures has been developed. It is based on two parametric models describing; i the rate of grain degraded in water at temperature and age given, in function of the content of free lime, the size and the structure of the grain, ii the expansion of the packing granular, pure or mixed with inert aggregates, exposed to a flow of steam. The combination of these two models with the Compressible Packing Model of LCPC allows then the prediction of the kinetics of expansion of a granular mixture, and the designation of

  1. X-Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 with Chandra

    Science.gov (United States)

    Gallagher, S. C.; Brandt, W. N.; Chartas, G.; Garmire, G. P.; Sambruna, R. M.

    2002-01-01

    With 40 ks of Clzandra ACIS-S3 exposure, new information on both the starburst and QSO components of the X-ray emission of Markarian 231, an ultraluminous infrared galaxy and broad absorption line QSO, has been obtained. The bulk of the X-ray luminosity is emitted from an unresolved nuclear point source, and the spectrum is remarkably hard, with the majority of the flux emitted above 2 keV. Most notably, significant nuclear variability (a decrease of -45% in approximately 6 hr) at energies above 2 keV indicates that Chuizdra has probed within light-hours of the central black hole. Although we concur with Maloney & Reynolds that the direct continuum is not observed, this variability coupled with the 188 eV upper limit on the equivalent width of the Fe K o emission line argues against the reflection-dominated model put forth by these authors based on their ASCA data. Instead, we favor a model in which a small, Compton-thick absorber blocks the direct X-rays, and only indirect, scattered X-rays from multiple lines of sight can reach the observer. Extended soft, thermal emission encompasses the optical extent of the galaxy and exhibits resolved structure. An off-nuclear X-ray source with a 0.35-8.0 keV luminosity of Lx = 7 x 10 sup39 ergs s sup -1 , consistent with the ultraluminous X-ray sources in other nearby starbursts, is detected. We also present an unpublished Faint Object Spectrograph spectrum from the Hirhhle Spuce Telescope archive showing the broad C IV absorption.

  2. Spatially resolving a starburst galaxy at hard X-ray energies: NuSTAR, CHANDRA, AND VLBA observations of NGC 253

    DEFF Research Database (Denmark)

    Wik, D. R.; Lehmer, B. D.; Hornschemeier, A. E.

    2014-01-01

    for the first time. As a follow up to our initial study of its nuclear region, we present the first results concerning the full galaxy from simultaneous NuSTAR, Chandra, and Very Long Baseline Array monitoring of the local starburst galaxy NGC 253. Above ~10 keV, nearly all the emission is concentrated within...... 253 is typical of starburst galaxies at higher redshift, their contribution to the E > 10 keV cosmic X-ray background is...

  3. CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Wang, Junfeng [Department of Astronomy, Physics Building, Xiamen University Xiamen, Fujian, 361005 (China); Storchi-Bergmann, Thaisa, E-mail: walter.maksym@cfa.harvard.edu [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, IF, CP 15051, 91501-970 Porto Alegre, RS (Brazil)

    2017-07-20

    The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra 's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble Space Telescope narrow-line images of [O iii], [S ii], and H α , as well as previously unpublished mid-ultraviolet (MUV) images. The X-rays provide unprecedented evidence that the S-shaped arms that envelope the nuclear radio outflows extend only ≲0.″2 (≲50 pc) across. The high-resolution multiwavelength data suggest that the extended narrow-line region is a complex multiphase structure in the circumnuclear interstellar medium (ISM). Its ionization structure is highly stratified with respect to outflow-driven bubbles in the bicone and varies dramatically on scales of ∼10 pc. Multiple findings show likely contributions from shocks to the feedback in regions where radio outflows from the AGN most directly influence the ISM. These findings include H α evidence for gas compression and extended MUV emission and are in agreement with existing STIS kinematics. Extended filamentary structure in the X-rays and optical suggests the presence of an undetected plasma component, whose existence could be tested with deeper radio observations.

  4. Biodiversity and Indigenous Uses of Medicinal Plant in the Chandra Prabha Wildlife Sanctuary, Chandauli District, Uttar Pradesh

    Directory of Open Access Journals (Sweden)

    Maurya Santosh Kumar

    2015-01-01

    Full Text Available Conventional medicines are very important part of Indian culture. In this study the outcome of two-year study of ethnomedicinal uses of plants in Chandra Prabha Wildlife Sanctuary (CPWLS and nearby area is reported. Information related to different plants which are used by local community in the treatment of many common diseases and well-being in the area was collected. Data on the use of medicinal plants were collected using structured interview of about 122 participants and thorough observations and conversations with local communities. Approximately 100 plants belonging to 43 families used by the local healers were reported in this study. The plant species with the highest fidelity level (Fl were Holarrhena antidysenterica, Lawsonia inermis, Gymnema sylvestre, Dalbergia sissoo, Cassia fistula Linn., Butea monosperma (Lam. Kuntze., Boerhaavia diffusa Linn., Albizia lebbeck Benth., Aegle marmelos Correa., Sphaeranthus indicus Linn., and Solanum surattense Burm. f. The most frequent ailments reported were hepatitis, jaundice, constipation, and skin and urinary problems. The parts of the plants most frequently used were fruit, roots, and whole plants (17% followed by leaves (16% and bark (15%. This study presents new research efforts and perspectives on the search for new drugs based on local uses of medicinal plants.

  5. PROBING X-RAY ABSORPTION AND OPTICAL EXTINCTION IN THE INTERSTELLAR MEDIUM USING CHANDRA OBSERVATIONS OF SUPERNOVA REMNANTS

    Energy Technology Data Exchange (ETDEWEB)

    Foight, Dillon R.; Slane, Patrick O. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Güver, Tolga [Istanbul University, Science Faculty, Department of Astronomy and Space Sciences, Beyazıt, 34119, Istanbul (Turkey); Özel, Feryal [Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

    2016-07-20

    We present a comprehensive study of interstellar X-ray extinction using the extensive Chandra supernova remnant (SNR) archive and use our results to refine the empirical relation between the hydrogen column density and optical extinction. In our analysis, we make use of the large, uniform data sample to assess various systematic uncertainties in the measurement of the interstellar X-ray absorption. Specifically, we address systematic uncertainties that originate from (i) the emission models used to fit SNR spectra; (ii) the spatial variations within individual remnants; (iii) the physical conditions of the remnant such as composition, temperature, and non-equilibrium regions; and (iv) the model used for the absorption of X-rays in the interstellar medium. Using a Bayesian framework to quantify these systematic uncertainties, and combining the resulting hydrogen column density measurements with the measurements of optical extinction toward the same remnants, we find the empirical relation N {sub H} = (2.87 ± 0.12) × 10{sup 21} A {sub V} cm{sup 2}, which is significantly higher than the previous measurements.

  6. Recent Chandra/HETGS and NuSTAR observations of the quasar PDS 456 and its Ultra-Fast Outflow

    Science.gov (United States)

    Boissay Malaquin, Rozenn; Marshall, Herman L.; Nowak, Michael A.

    2018-01-01

    Evidence is growing that the interaction between outflows from active galactic nuclei (AGN) and their surrounding medium may play an important role in galaxy evolution, i.e. in the regulation of star formation in galaxies, through AGN feedback processes. Indeed, powerful outflows, such as the ultra-fast outflows (UFOs) that can reach mildly relativistic velocities of 0.2-0.4c, could blow away a galaxy’s reservoir of star-forming gas and hence quench the star formation in host galaxies. The low-redshift (z=0.184) radio-quiet quasar PDS 456 has showed the presence of a strong and blueshifted absorption trough in the Fe K band above 7 keV, that has been associated with the signature of such a fast and highly ionized accretion disk wind of a velocity of 0.25-0.3c. This persistent and variable feature has been detected in many observations of PDS 456, in particular by XMM-Newton, Suzaku and NuSTAR, together with other blueshifted absorption lines in the soft energy band (e.g. Nardini et al. 2015, Reeves et al. 2016). I will present here the results of the analysis of recent and contemporaneous high-resolution Chandra/HETGS and NuSTAR observations of PDS 456, and compare them with the previous findings.

  7. Searching for faint AGN in the CDFS: an X-ray (Chandra) vs optical variability (HST) comparison.

    Science.gov (United States)

    Georgantopoulos, I.; Pouliasis, E.; Bonanos, A.; Sokolovsky, K.; Yang, M.; Hatzidimitriou, D.; Bellas, I.; Gavras, P.; Spetsieri, Z.

    2017-10-01

    X-ray surveys are believed to be the most efficient way to detect AGN. Recently though, optical variability studies are claimed to probe even fainter AGN. We are presenting results from an HST study aimed to identify Active Galactic Nuclei (AGN) through optical variability selection in the CDFS.. This work is part of the 'Hubble Catalogue of Variables'project of ESA that aims to identify variable sources in the Hubble Source Catalogue.' In particular, we used Hubble Space Telescope (HST) z-band images taken over 5 epochs and performed aperture photometry to derive the lightcurves of the sources. Two statistical methods (standard deviation & interquartile range) resulting in a final sample of 175 variable AGN candidates, having removed the artifacts by visual inspection and known stars and supernovae. The fact that the majority of the sources are extended and variable indicates AGN activity. We compare the efficiency of the method by comparing with the 7Ms Chandra detections. Our work shows that the optical variability probes AGN at comparable redshifts but at deeper optical magnitudes. Our candidate AGN (non detected in X-rays) have luminosities of L_x<6×10^{40} erg/sec at z˜0.7 suggesting that these are associated with low luminosity Seyferts and LINERS.

  8. FRONTIER FIELDS CLUSTERS: DEEP CHANDRA OBSERVATIONS OF THE COMPLEX MERGER MACS J1149.6+2223

    Energy Technology Data Exchange (ETDEWEB)

    Ogrean, G. A.; Weeren, R. J. van; Jones, C.; Forman, W.; Andrade-Santos, F.; Murray, S. S.; Nulsen, P.; Bulbul, E.; Kraft, R.; Randall, S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Dawson, W. A. [Lawrence Livermore National Lab, 7000 East Avenue, Livermore, CA 94550 (United States); Golovich, N. [University of California, One Shields Avenue, Davis, CA 95616 (United States); Roediger, E. [Astronomy and Astrophysics Section, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Zitrin, A.; Sayers, J. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Goulding, A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Umetsu, K. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Mroczkowski, T. [U.S. Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Bonafede, A. [Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany); Churazov, E., E-mail: gogrean@cfa.harvard.edu [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741, Garching (Germany); and others

    2016-03-10

    The Hubble Space Telescope Frontier Fields cluster MACS J1149.6+2223 is one of the most complex merging clusters, believed to consist of four dark matter halos. We present results from deep (365 ks) Chandra observations of the cluster, which reveal the most distant cold front (z  =  0.544) discovered to date. In the cluster outskirts, we also detect hints of a surface brightness edge that could be the bow shock preceding the cold front. The substructure analysis of the cluster identified several components with large relative radial velocities, thus indicating that at least some collisions occur almost along the line of sight. The inclination of the mergers with respect to the plane of the sky poses significant observational challenges at X-ray wavelengths. MACS J1149.6+2223 possibly hosts a steep-spectrum radio halo. If the steepness of the radio halo is confirmed, then the radio spectrum, combined with the relatively regular ICM morphology, could indicate that MACS J1149.6+2223 is an old merging cluster.

  9. THE CHANDRA MULTI-WAVELENGTH PROJECT: OPTICAL SPECTROSCOPY AND THE BROADBAND SPECTRAL ENERGY DISTRIBUTIONS OF X-RAY-SELECTED AGNs

    Energy Technology Data Exchange (ETDEWEB)

    Trichas, Markos; Green, Paul J.; Aldcroft, Tom; Kim, Dong-Woo; Mossman, Amy [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Silverman, John D. [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-shi, Chiba 277-8568 (Japan); Barkhouse, Wayne [Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202 (United States); Cameron, Robert A. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Constantin, Anca [Department of Physics and Astronomy, James Madison University, PHCH, Harrisonburg, VA 22807 (United States); Ellison, Sara L. [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 1A1 (Canada); Foltz, Craig [Division of Astronomical Sciences, National Science Foundation, 4201 Wilson Blvd., Arlington, VA 22230 (United States); Haggard, Daryl [Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Jannuzi, Buell T. [NOAO, Kitt Peak National Observatory, Tucson, AZ 85726 (United States); Marshall, Herman L. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States); Perez, Laura M. [Department of Astronomy, California Institute of Technology, 1200 East California Blvd, Pasadena, CA 91125 (United States); Romero-Colmenero, Encarni [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Ruiz, Angel [Osservatorio Astronomico di Brera-INAF, Milan (Italy); Smith, Malcolm G., E-mail: mtrichas@cfa.harvard.edu [Cerro Tololo Interamerican Observatory, La Serena (Chile); and others

    2012-06-01

    From optical spectroscopy of X-ray sources observed as part of the Chandra Multi-wavelength Project (ChaMP), we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic follow-up using the FLWO/1.5 m, SAAO/1.9 m, WIYN 3.5 m, CTIO/4 m, KPNO/4 m, Magellan/6.5 m, MMT/6.5 m, and Gemini/8 m telescopes, and from archival Sloan Digital Sky Survey (SDSS) spectroscopy. We classify the optical counterparts as 50% broad-line active galactic nuclei (AGNs), 16% emission line galaxies, 14% absorption line galaxies, and 20% stars. We detect QSOs out to z {approx} 5.5 and galaxies out to z {approx} 3. We have compiled extensive photometry, including X-ray (ChaMP), ultraviolet (GALEX), optical (SDSS and ChaMP-NOAO/MOSAIC follow-up), near-infrared (UKIDSS, Two Micron All Sky Survey, and ChaMP-CTIO/ISPI follow-up), mid-infrared (WISE), and radio (FIRST and NVSS) bands. Together with our spectroscopic information, this enables us to derive detailed spectral energy distributions (SEDs) for our extragalactic sources. We fit a variety of template SEDs to determine bolometric luminosities, and to constrain AGNs and starburst components where both are present. While {approx}58% of X-ray Seyferts (10{sup 42} erg s{sup -1} < L{sub 2-10keV} <10{sup 44} erg s{sup -1}) require a starburst event (>5% starburst contribution to bolometric luminosity) to fit observed photometry only 26% of the X-ray QSO (L{sub 2-10keV} >10{sup 44} erg s{sup -1}) population appear to have some kind of star formation contribution. This is significantly lower than for the Seyferts, especially if we take into account torus contamination at z > 1 where the majority of our X-ray QSOs lie. In addition, we observe a rapid drop of the percentage of starburst contribution as X-ray luminosity increases. This is consistent with the quenching of star formation by powerful QSOs, as predicted by the merger model, or with a time lag between the peak of star formation and QSO

  10. A CHANDRA OBSERVATION OF SUPERNOVA REMNANT G350.1-0.3 AND ITS CENTRAL COMPACT OBJECT

    International Nuclear Information System (INIS)

    Lovchinsky, I.; Slane, P.; Gaensler, B. M.; Hughes, J. P.; Ng, C.-Y.; Lazendic, J. S.; Gelfand, J. D.; Brogan, C. L.

    2011-01-01

    We present a new Chandra observation of supernova remnant (SNR) G350.1-0.3. The high-resolution X-ray data reveal previously unresolved filamentary structures and allow us to perform detailed spectroscopy in the diffuse regions of this SNR. Spectral analysis demonstrates that the region of brightest emission is dominated by hot, metal-rich ejecta while the ambient material along the perimeter of the ejecta region and throughout the remnant's western half is mostly low-temperature, shocked interstellar/circumstellar medium with solar-type composition. The data reveal that the emission extends far to the west of the ejecta region and imply a lower limit of 6.6 pc on the diameter of the source (at a distance of 4.5 kpc). We show that G350.1-0.3 is likely in the free expansion (ejecta-dominated) stage and calculate an age of 600-1200 years. The derived relationship between the shock velocity and the electron/proton temperature ratio is found to be entirely consistent with that of other SNRs. We perform spectral fits on the X-ray source XMMU J172054.5-372652, a candidate central compact object (CCO), and find that its spectral properties fall within the typical range of other CCOs. We also present archival 24 μm data of G350.1-0.3 taken with the Spitzer Space Telescope during the MIPSGAL galactic survey and find that the infrared and X-ray morphologies are well correlated. These results help to explain this remnant's peculiar asymmetries and shed new light on its dynamics and evolution.

  11. Hydrostatic Chandra X-ray analysis of SPT-selected galaxy clusters - I. Evolution of profiles and core properties

    Science.gov (United States)

    Sanders, J. S.; Fabian, A. C.; Russell, H. R.; Walker, S. A.

    2018-02-01

    We analyse Chandra X-ray Observatory observations of a set of galaxy clusters selected by the South Pole Telescope using a new publicly available forward-modelling projection code, MBPROJ2, assuming hydrostatic equilibrium. By fitting a power law plus constant entropy model we find no evidence for a central entropy floor in the lowest entropy systems. A model of the underlying central entropy distribution shows a narrow peak close to zero entropy which accounts for 60 per cent of the systems, and a second broader peak around 130 keV cm2. We look for evolution over the 0.28-1.2 redshift range of the sample in density, pressure, entropy and cooling time at 0.015R500 and at 10 kpc radius. By modelling the evolution of the central quantities with a simple model, we find no evidence for a non-zero slope with redshift. In addition, a non-parametric sliding median shows no significant change. The fraction of cool-core clusters with central cooling times below 2 Gyr is consistent above and below z = 0.6 (˜30-40 per cent). Both by comparing the median thermodynamic profiles, centrally biased towards cool cores, in two redshift bins, and by modelling the evolution of the unbiased average profile as a function of redshift, we find no significant evolution beyond self-similar scaling in any of our examined quantities. Our average modelled radial density, entropy and cooling-time profiles appear as power laws with breaks around 0.2R500. The dispersion in these quantities rises inwards of this radius to around 0.4 dex, although some of this scatter can be fitted by a bimodal model.

  12. THE COMPLEX CIRCUMNUCLEAR ENVIRONMENT OF THE BROAD-LINE RADIO GALAXY 3C 390.3 REVEALED BY CHANDRA HETG

    Energy Technology Data Exchange (ETDEWEB)

    Tombesi, F.; Kallman, T.; Leutenegger, M. A. [X-ray Astrophysics Laboratory, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Reeves, J. N. [Center for Space Science and Technology, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Reynolds, C. S.; Mushotzky, R. F.; Behar, E. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Braito, V. [INAF—Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate (Italy); Cappi, M., E-mail: francesco.tombesi@nasa.gov, E-mail: ftombesi@astro.umd.edu [Department of Physics, Technion 32000, Haifa 32000 (Israel)

    2016-10-20

    We present the first high spectral resolution X-ray observation of the broad-line radio galaxy 3C 390.3 obtained with the high-energy transmission grating spectrometer on board the Chandra X-ray Observatory . The spectrum shows complex emission and absorption features in both the soft X-rays and Fe K band. We detect emission and absorption lines in the energy range E = 700–1000 eV associated with ionized Fe L transitions (Fe XVII–XX). An emission line at the energy of E ≃ 6.4 keV consistent with the Fe K α is also observed. Our best-fit model requires at least three different components: (i) a hot emission component likely associated with the hot interstellar medium in this elliptical galaxy with temperature kT = 0.5 ± 0.1 keV; (ii) a warm absorber with ionization parameter log ξ = 2.3 ± 0.5 erg s{sup −1} cm, column density log N {sub H} = 20.7 ± 0.1 cm{sup −2}, and outflow velocity v {sub out} < 150 km s{sup −1}; and (iii) a lowly ionized reflection component in the Fe K band likely associated with the optical broad-line region or the outer accretion disk. These evidences suggest the possibility that we are looking directly down the ionization cone of this active galaxy and that the central X-ray source only photoionizes along the unobscured cone. This is overall consistent with the angle-dependent unified picture of active galactic nuclei.

  13. FRONTIER FIELDS CLUSTERS: CHANDRA AND JVLA VIEW OF THE PRE-MERGING CLUSTER MACS J0416.1-2403

    Energy Technology Data Exchange (ETDEWEB)

    Ogrean, G. A.; Weeren, R. J. van; Jones, C.; Nulsen, P. E. J.; Forman, W.; Murray, S. S.; Randall, S.; Kraft, R.; David, L.; Andrade-Santos, F.; Goulding, A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Clarke, T. E.; Mroczkowski, T. [U.S. Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Sayers, J.; Zitrin, A. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Pandey-Pommier, M. [Centre de Recherche Astrophysique de Lyon, Observatoire de Lyon, 9 av Charles André, F-69561 Saint Genis Laval Cedex (France); Churazov, E. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741, Garching (Germany); Bonafede, A. [Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112 21029 Hamburg (Germany); Merten, J. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Umetsu, K., E-mail: gogrean@cfa.harvard.edu [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); and others

    2015-10-20

    Merging galaxy clusters leave long-lasting signatures on the baryonic and non-baryonic cluster constituents, including shock fronts, cold fronts, X-ray substructure, radio halos, and offsets between the dark matter (DM) and the gas components. Using observations from Chandra, the Jansky Very Large Array, the Giant Metrewave Radio Telescope, and the Hubble Space Telescope, we present a multiwavelength analysis of the merging Frontier Fields cluster MACS J0416.1-2403 (z = 0.396), which consists of NE and SW subclusters whose cores are separated on the sky by ∼250 kpc. We find that the NE subcluster has a compact core and hosts an X-ray cavity, yet it is not a cool core. Approximately 450 kpc south–southwest of the SW subcluster, we detect a density discontinuity that corresponds to a compression factor of ∼1.5. The discontinuity was most likely caused by the interaction of the SW subcluster with a less massive structure detected in the lensing maps SW of the subcluster's center. For both the NE and the SW subclusters, the DM and the gas components are well-aligned, suggesting that MACS J0416.1-2403 is a pre-merging system. The cluster also hosts a radio halo, which is unusual for a pre-merging system. The halo has a 1.4 GHz power of (1.3 ± 0.3) × 10{sup 24} W Hz{sup −1}, which is somewhat lower than expected based on the X-ray luminosity of the cluster if the spectrum of the halo is not ultra-steep. We suggest that we are either witnessing the birth of a radio halo, or have discovered a rare ultra-steep spectrum halo.

  14. X-Ray Jet Emission from the Black Hole X-Ray Binary XTE J1550-564 with Chandra in 2000

    OpenAIRE

    Tomsick, J.A.; Corbel, S.; Fender, R.P.; Miller, J.M.; Orosz, J.A.; Tzioumis, T.; Wijnands, R.A.D.; Kaaret, P.

    2003-01-01

    We have discovered an X-ray jet due to material ejected from the black hole X-ray transient XTE J1550-564. The discovery was first reported by Corbel et al. (Science, 298, 196 and astro-ph/0210224), and here, we present an analysis of the three Chandra observations made between 2000 June and 2000 September. For these observations, a source is present that moves in an eastward direction away from the point source associated with the compact object. The separation between the new source and the...

  15. Observations of the Crab Nebula with the Chandra X-Ray Observatory During the Gamma-Ray Flare of 2011 April

    Science.gov (United States)

    Weisskopf, Martin C.

    2012-01-01

    Recently, using the AGILE and Fermi satellites, gamma-ray flares have been discovered from the direction of the Crab Nebula (Tavani et al. 2011, Abdo et al. 2011). We have been using the Chandra X-Ray observatory to monitor the Crab on a monthly cadence since just after the 2010 September gamma-ray flare. We were fortunate to trigger series of pre-planned target of opportunity observations during the 2011 April flare. We present the results of these observations and address some implications both for now and for the future.

  16. CORONA, JET, AND RELATIVISTIC LINE MODELS FOR SUZAKU/RXTE/CHANDRA-HETG OBSERVATIONS OF THE CYGNUS X-1 HARD STATE

    International Nuclear Information System (INIS)

    Nowak, Michael A.; Trowbridge, Sarah N.; Davis, John E.; Hanke, Manfred; Wilms, Joern; Markoff, Sera B.; Maitra, Dipankar; Tramper, Frank; Pottschmidt, Katja; Coppi, Paolo

    2011-01-01

    Using Suzaku and the Rossi X-ray Timing Explorer (RXTE), we have conducted a series of four simultaneous observations of the galactic black hole candidate Cyg X-1 in what were historically faint and spectrally hard 'low states'. Additionally, all of these observations occurred near superior conjunction with our line of sight to the X-ray source passing through the dense phases of the 'focused wind' from the mass donating secondary. One of our observations was also simultaneous with observations by the Chandra-High Energy Transmission Grating (HETG). These latter spectra are crucial for revealing the ionized absorption due to the secondary's focused wind. Such absorption is present and must be accounted for in all four spectra. These simultaneous data give an unprecedented view of the 0.8-300 keV spectrum of Cyg X-1, and hence bear upon both corona and X-ray emitting jet models of black hole hard states. Three models fit the spectra well: coronae with thermal or mixed thermal/non-thermal electron populations and jets. All three models require a soft component that we fit with a low temperature disk spectrum with an inner radius of only a few tens of GM/c 2 . All three models also agree that the known spectral break at 10 keV is not solely due to the presence of reflection, but each gives a different underlying explanation for the augmentation of this break. Thus, whereas all three models require that there is a relativistically broadened Fe line, the strength and inner radius of such a line is dependent upon the specific model, thus making premature line-based estimates of the black hole spin in the Cyg X-1 system. We look at the relativistic line in detail, accounting for the narrow Fe emission and ionized absorption detected by HETG. Although the specific relativistic parameters of the line are continuum dependent, none of the broad line fits allow for an inner disk radius that is >40 GM/c 2 .

  17. Photoionization Modeling of Oxygen K Absorption in the Interstellar Medium:. [The Chandra Grating Spectra of XTE J1817-330

    Science.gov (United States)

    Gatuzz, E.; Garcia, J.; Mendoza, C.; Kallman, T. R.; Witthoeft, M.; Lohfink, A.; Bautista, M. A.; Palmeri, P.; Quinet, P.

    2013-01-01

    We present detailed analyses of oxygen K absorption in the interstellar medium (ISM) using four high-resolution Chandra spectra toward the X-ray low-mass binary XTE J1817-330. The 11-25 Angstrom broadband is described with a simple absorption model that takes into account the pile-up effect and results in an estimate of the hydrogen column density. The oxygen K-edge region (21-25 Angstroms) is fitted with the physical warmabs model, which is based on a photoionization model grid generated with the xstar code with the most up-to-date atomic database. This approach allows a benchmark of the atomic data which involves wavelength shifts of both the K lines and photoionization cross sections in order to fit the observed spectra accurately. As a result we obtain a column density of N(sub H) = 1.38 +/- 0.01 × 10(exp 21) cm(exp -2); an ionization parameter of log xi = -2.70 +/- 0.023; an oxygen abundance of A(sub O) = 0.689 (+0.015/-0.010); and ionization fractions of O(sub I)/O = 0.911, O(sub II)/O = 0.077, and O(sub III)/O = 0.012 that are in good agreement with results from previous studies. Since the oxygen abundance in warmabs is given relative to the solar standard of Grevesse & Sauval, a rescaling with the revision by Asplund et al. yields A(sub O) = 0.952(+0.020/-0.013), a value close to solar that reinforces the new standard.We identify several atomic absorption lines-K(alpha), K(beta), and K(gamma) in O(sub I) and O(sub II) and K(alpha) in O(sub III), O(sub VI), and O(sub VII)-the last two probably residing in the neighborhood of the source rather than in the ISM. This is the first firm detection of oxygen K resonances with principal quantum numbers n greater than 2 associated with ISM cold absorption.

  18. Photoionization Modeling of Oxygen K Absorption in the Interstellar Medium: The Chandra Grating Spectra of XTE J1817-330

    Science.gov (United States)

    Gatuzz, E.; Garcia, J.; Menodza, C.; Kallman, T. R.; Witthoeft, M.; Lohfink, A.; Bautista, M. A.; Palmeri, P.; Quinet, P.

    2013-01-01

    We present detailed analyses of oxygen K absorption in the interstellar medium (ISM) using four high-resolution Chandra spectra towards the X-ray low-mass binary XTE J1817-330. The 11-25 A broadband is described with a simple absorption model that takes into account the pileup effect and results in an estimate of the hydrogen column density. The oxygen K-edge region (21-25 A) is fitted with the physical warmabs model, which is based on a photoionization model grid generated with the XSTAR code with the most up-to-date atomic database. This approach allows a benchmark of the atomic data which involves wavelength shifts of both the K lines and photoionization cross sections in order to fit the observed spectra accurately. As a result we obtain: a column density of N(sub H) = 1.38 +/- 0.01 x 10(exp 21) cm(exp -2); ionization parameter of log xi = .2.70 +/- 0.023; oxygen abundance of A(sub O) = 0.689(exp +0.015./-0.010); and ionization fractions of O I/O = 0.911, O II/O = 0.077, and O III/O = 0.012 that are in good agreement with previous studies. Since the oxygen abundance in warmabs is given relative to the solar standard of Grevesse and Sauval (1998), a rescaling with the revision by Asplund et al. (2009) yields A(sub O) = 0.952(exp +0.020/-0.013, a value close to solar that reinforces the new standard. We identify several atomic absorption lines.K-alpha , K-beta, and K-gamma in O I and O II; and K-alpha in O III, O VI, and O VII--last two probably residing in the neighborhood of the source rather than in the ISM. This is the first firm detection of oxygen K resonances with principal quantum numbers n greater than 2 associated to ISM cold absorption.

  19. PHOTOIONIZATION MODELING OF OXYGEN K ABSORPTION IN THE INTERSTELLAR MEDIUM: THE CHANDRA GRATING SPECTRA OF XTE J1817-330

    International Nuclear Information System (INIS)

    Gatuzz, E.; Mendoza, C.; García, J.; Lohfink, A.; Kallman, T. R.; Witthoeft, M.; Bautista, M. A.; Palmeri, P.; Quinet, P.

    2013-01-01

    We present detailed analyses of oxygen K absorption in the interstellar medium (ISM) using four high-resolution Chandra spectra toward the X-ray low-mass binary XTE J1817-330. The 11-25 Å broadband is described with a simple absorption model that takes into account the pile-up effect and results in an estimate of the hydrogen column density. The oxygen K-edge region (21-25 Å) is fitted with the physical warmabs model, which is based on a photoionization model grid generated with the XSTAR code with the most up-to-date atomic database. This approach allows a benchmark of the atomic data which involves wavelength shifts of both the K lines and photoionization cross sections in order to fit the observed spectra accurately. As a result we obtain a column density of N H = 1.38 ± 0.01 × 10 21 cm –2 ; an ionization parameter of log ξ = –2.70 ± 0.023; an oxygen abundance of A O = 0.689 +0.015 -0.010 ; and ionization fractions of O I/O = 0.911, O II/O = 0.077, and O III/O = 0.012 that are in good agreement with results from previous studies. Since the oxygen abundance in warmabs is given relative to the solar standard of Grevesse and Sauval, a rescaling with the revision by Asplund et al. yields A O =0.952 +0.020 -0.013 , a value close to solar that reinforces the new standard. We identify several atomic absorption lines—Kα, Kβ, and Kγ in O I and O II and Kα in O III, O VI, and O VII—the last two probably residing in the neighborhood of the source rather than in the ISM. This is the first firm detection of oxygen K resonances with principal quantum numbers n > 2 associated with ISM cold absorption.

  20. CHANDRA CHARACTERIZATION OF X-RAY EMISSION IN THE YOUNG F-STAR BINARY SYSTEM HD 113766

    Energy Technology Data Exchange (ETDEWEB)

    Lisse, C. M. [Planetary Exploration Branch, Space Exploration Sector, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Christian, D. J. [Department of Physics and Astronomy, California State University Northridge, 18111 Nordhoff Street, Northridge, CA 91330 (United States); Wolk, S. J. [Chandra X-ray Center, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Günther, H. M. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, NE83-569, Cambridge, MA 02139 (United States); Chen, C. H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Grady, C. A., E-mail: carey.lisse@jhuapl.edu, E-mail: damian.christian@csun.edu, E-mail: swolk@cfa.harvard.edu, E-mail: hgunther@mit.edu, E-mail: cchen@stsci.edu, E-mail: carol.a.grady@nasa.gov [Eureka Scientific and Goddard Space Flight Center, Code 667, NASA-GSFC, Greenbelt, MD 20771 (United States)

    2017-02-01

    Using Chandra , we have obtained imaging X-ray spectroscopy of the 10–16 Myr old F-star binary HD 113766. We individually resolve the 1.″4 separation binary components for the first time in the X-ray and find a total 0.3–2.0 keV luminosity of 2.2 × 10{sup 29} erg s{sup −1}, consistent with previous RASS estimates. We find emission from the easternmost, infrared-bright, dusty member HD 113766A to be only ∼10% that of the western, infrared-faint member HD 113766B. There is no evidence for a 3rd late-type stellar or substellar member of HD 113766 with L {sub x} > 6 × 10{sup 25} erg s{sup −1} within 2′ of the binary pair. The ratio of the two stars’ X-ray luminosity is consistent with their assignments as F2V and F6V by Pecaut et al. The emission is soft for both stars, kT {sub Apec} = 0.30–0.50 keV, suggesting X-rays produced by stellar rotation and/or convection in young dynamos, but not accretion or outflow shocks, which we rule out. A possible 2.8 ± 0.15 (2 σ ) hr modulation in the HD 113766B X-ray emission is seen, but at very low confidence and of unknown provenance. Stellar wind drag models corresponding to L {sub x} ∼ 2 × 10{sup 29} erg s{sup −1} argue for a 1 mm dust particle lifetime around HD 113766B of only ∼90,0000 years, suggesting that dust around HD 113766B is quickly removed, whereas 1 mm sized dust around HD 113766A can survive for >1.5 × 10{sup 6} years. At 10{sup 28}–10{sup 29} erg s{sup −1} X-ray luminosity, astrobiologically important effects, like dust warming and X-ray photolytic organic synthesis, are likely for any circumstellar material in the HD 113766 systems.

  1. Immediate effect of chandra nadi pranayama (left unilateral forced nostril breathing on cardiovascular parameters in hypertensive patients

    Directory of Open Access Journals (Sweden)

    Ananda Balayogi Bhavanani

    2012-01-01

    Full Text Available Introduction : Recent studies have reported differential physiological and psychological effects produced by exclusive right and left nostril breathing and clinical research is required to prove immediate and sustained efficacy of these techniques in various psychosomatic conditions such as hypertension (HT. The present study was designed to determine immediate effects of 27 rounds of exclusive left nostril breathing, a yogic pranayama technique known as chandra nadi pranayama (CNP on cardiovascular parameters in patients of essential HT. Materials and Methods : Twenty two patients of essential HT under regular standard medical management were individually taught to perform CNP by a qualified yoga instructor with a regularity of 6 breaths/min throughout a performance of 27 rounds of CNP. Pre and post intervention heart rate (HR and blood pressure (BP measurements were recorded using non-invasive semi-automatic BP monitor and Students t test for paired data used to determine significant differences. Results : Twenty seven rounds of CNP produced an immediate decrease in all the measured cardiovascular parameters with the decrease in HR, systolic pressure (SP, pulse pressure, rate-pressure product and double product being statistically significant. Further, gender-based sub-analysis of our data revealed that our male participants evidenced significant reductions in HR and SP with an insignificant decrease in diastolic pressure, while in female participants only HR decreased significantly with an insignificant decrease in SP. Discussion and Conclusion : It is concluded that CNP is effective in reducing HR and SP in hypertensive patients on regular standard medical management. To the best of our knowledge, there are no previously published reports on immediate effects of left UFNB in patients of HT and ours is the first to report on this beneficial clinical effect. This may be due to a normalization of autonomic cardiovascular rhythms with increased

  2. THE CORES OF THE Fe Kα LINES IN ACTIVE GALACTIC NUCLEI: AN EXTENDED CHANDRA HIGH ENERGY GRATING SAMPLE

    International Nuclear Information System (INIS)

    Shu, X. W.; Wang, J. X.; Yaqoob, T.

    2010-01-01

    We extend the study of the core of the Fe Kα emission line at ∼6.4 keV in Seyfert galaxies reported by Yaqoob and Padmanabhan using a larger sample observed by the Chandra high-energy grating (HEG). The sample consists of 82 observations of 36 unique sources with z H 23 cm -2 ) Seyfert galaxies to date. From an empirical and uniform analysis, we present measurements of the Fe Kα line centroid energy, flux, equivalent width (EW), and intrinsic width (FWHM). The Fe Kα line is detected in 33 sources, and its centroid energy is constrained in 32 sources. In 27 sources, the statistical quality of the data is good enough to yield measurements of the FWHM. We find that the distribution in the line centroid energy is strongly peaked around the value for neutral Fe, with over 80% of the observations giving values in the range 6.38-6.43 keV. Including statistical errors, 30 out of 32 sources (∼94%) have a line centroid energy in the range 6.35-6.47 keV. The mean EW, among the observations in which a non-zero lower limit could be measured, was 53 ± 3 eV. The mean FWHM from the subsample of 27 sources was 2060 ± 230 km s -1 . The mean EW and FWHM are somewhat higher when multiple observations for a given source are averaged. From a comparison with the Hβ optical emission-line widths (or, for one source, Brα), we find that there is no universal location of the Fe Kα line-emitting region relative to the optical broad-line region (BLR). In general, a given source may have contributions to the Fe Kα line flux from parsec-scale distances from the putative black hole, down to matter a factor ∼2 closer to the black hole than the BLR. We confirm the presence of the X-ray Baldwin effect, an anti-correlation between the Fe Kα line EW and X-ray continuum luminosity. The HEG data have enabled isolation of this effect to the narrow core of the Fe Kα line.

  3. Maheshwari, Prof. Satish Chandra

    Indian Academy of Sciences (India)

    Delhi), FNA, FNASc. Date of birth: 4 October 1933. Specialization: Physiology & Biochemistry of Plant Growth & Development and Plant Molecular Biology Address: 251/56, Prathap Enclave, Haldighati Road, Jaipur 302 033, Rajasthan Contact ...

  4. Chaturvedi, Prof. Umesh Chandra

    Indian Academy of Sciences (India)

    Lucknow), FRC Path. (London), FAMS, FNA, FNASc, FAAM(USA). Date of birth: 2 March 1939. Specialization: Medical Microbiology, Virology and Immunology Address: 201, Annapurna Apartments, No. 1, Bishop Rocky Street, Faizabad Road, ...

  5. Kundu, Dr Gopal Chandra

    Indian Academy of Sciences (India)

    Date of birth: 2 November 1959. Specialization: Tumour Biology, Regulation of Gene Expression, Angiogenesis and Nanomedicine Address: Scientist G, National Centre for Cell Science, NCCS Complex, Pune 411 007, Maharashtra Contact: Office: (020) 2570 8104. Mobile: 94225 06548. Fax: (020) 2569 2259

  6. Thakur, Dr Vikram Chandra

    Indian Academy of Sciences (India)

    Date of birth: 15 January 1940. Specialization: Structural Geology, Tectonics of Himalayan Geology and Active Tectonics Address: 9/12 (Lane 9), Ashirwad Eclave, Dehra Dun 248 001, Uttarakhand Contact: Residence: (0135) 276 1271. Mobile: 98970 46455. Email: thakurvc12@gmail.com. YouTube; Twitter; Facebook ...

  7. Sir Prafulla Chandra Ray

    Indian Academy of Sciences (India)

    As the results of their labours we are now in possession of ample facts and data, which enable us to form some idea of the knowledge of the Hindus of old in the fields of Philosophy and Mathematics including Astronomy, Arithmetic, Algebra, Trigonom- etry, and Geometry. Even Medicine has received some share of attention ...

  8. Ranu, Prof. Brindaban Chandra

    Indian Academy of Sciences (India)

    Jadavpur), FNA. Date of birth: 1 August 1949. Specialization: Visible Light Photocatalysed Reactions, Green Chemistry, Indium-mediated Supported Metal and Metal Nanoparticle-catalysed Reactions, Organic Synthesis Address: Department of ...

  9. Sir Prafulla Chandra Ray

    Indian Academy of Sciences (India)

    building, was now proving quite inadequate to meet the increased demands made upon it. Although practical work for the F.A. in chemistry ... plan [of a new building] submitted to it. I had a copy of the reprint of the description of ... and some of these were incorporated into our new plan. We moved to the new buildings at the ...

  10. Agrawal, Prof. Prahlad Chandra

    Indian Academy of Sciences (India)

    Date of birth: 15 April 1941. Specialization: X-ray Astronomy and Experimental High Energy Astrophysics Address: 405, Vigyan Scientists' CHS, Plot No. 23, Sector 17, Vashi, Navi Mumbai 400 703, Maharashtra Contact: Office: (022) 2653 0230. Residence: (022) 2789 9894. Mobile: 98673 43442

  11. Lakhotia, Prof. Subhash Chandra

    Indian Academy of Sciences (India)

    Ph.D. (Calcutta), FNA, FNASc. Date of birth: 4 October 1945. Specialization: Ayurvedic Biology, Cytogenetics, Gene Expression, Stress Biology and Molecular Biology Address: INSA Senior Scientist, Department of Zoology, Banaras Hindu University, Varanasi 221 005, U.P. Contact: Office: (0542) 236 8145, (0542) 236 8457

  12. Mishra, Dr Gyan Chandra

    Indian Academy of Sciences (India)

    Date of birth: 15 August 1947. Specialization: Immunology and Cell Biology Address: NASI Senior Scientist, National Centre for Cell Science, NCCS Complex, Ganeshkhind, Pune 411 007, Maharashtra Contact: Office: (020) 2570 8283. Residence: (020) 2720 1638. Mobile: 94225 22705. Fax: (020) 2569 7756

  13. Chandra, Prof. Nagasuma

    Indian Academy of Sciences (India)

    Date of birth: 16 May 1965. Specialization: Protein Structure, Algorithm Development, Systems Biology, Bioinformatics, Genomic & Clinical Data Analysis Address: Department of Biochemistry, Indian Institute of Science, Bengaluru 560 012, Karnataka Contact: Office: (080) 2293 2892. Residence: (080) 2349 2996

  14. Chandra, Prof. Nagasuma

    Indian Academy of Sciences (India)

    . Date of birth: 16 May 1965. Specialization: Protein Structure, Algorithm Development, Systems Biology, Bioinformatics, Genomic & Clinical Data Analysis Address: Department of Biochemistry, Indian Institute of Science, Bengaluru 560 012, ...

  15. Monitoring Chandra Observations of the Quasi-persistent Neutron Star X-Ray Transient MXB 1659-29 in Quiescence: The Cooling Curve of the Heated Neutron Star Crust

    NARCIS (Netherlands)

    Wijnands, R.A.D.; Homan, J.; Miller, J.M.; Lewin, W.H.G.

    2004-01-01

    We have observed the quasi-persistent neutron star X-ray transient and eclipsing binary MXB 1659-29 in quiescence on three occasions with Chandra. The purpose of our observations was to monitor the quiescent behavior of the source after its last prolonged (~2.5 yr) outburst that ended in 2001

  16. Chandra/High Energy Transmission Grating Spectrometer Spectroscopy of the Galactic Black Hole GX 339-4: A Relativistic Iron Emission Line and Evidence for a Seyfert-like Warm Absorber

    NARCIS (Netherlands)

    Miller, J.M.; Raymond, J.; Fabian, A.C.; Homan, J.; Nowak, M.A.; Wijnands, R.A.D.; van der Klis, M.; Belloni, T.; Tomsick, J.A.; Smith, D.M.; Charles, P.A.; Lewin, W.H.G.

    2004-01-01

    We observed the Galactic black hole GX 339-4 with the Chandra High Energy Transmission Grating Spectrometer (HETGS) for 75 ks during the decline of its 2002-2003 outburst. The sensitivity of this observation provides an unprecedented glimpse of a Galactic black hole at about a tenth of the

  17. Implications of the Detection of X-rays From Pluto by Chandra for Its Solar Wind - Neutral Atmosphere Interaction

    Science.gov (United States)

    Lisse, C. M.

    2016-12-01

    Using the Chandra X-Ray Observatory, we have obtained low-resolution imaging X-ray spectrophotometry of the Pluto system in support of the New Horizons (NH) flyby. In a total of 174 ksec of on-target time, we measured 8 photons from 0.31 to 0.60 keV in a co-moving 11 x 11 pixel2 box (the 90% flux aperture for fixed background sources in the field) measuring 121,000 x 121,000 km2 (or 100 x 100 RPluto) at Pluto. The Pluto photons do not have the spectral shape of the background, are coincident with a 90% flux aperture co-moving with Pluto, and are not confused with any background source, so we consider them as sourced from the Pluto system. Allowing for background, we find a net signal of 6.8 counts and a statistical noise level of 1.2 counts, for a detection of Pluto at > 99.95%. The mean 0.31 - 0.60 keV X-ray power from Pluto is 200 +200/-100 MW, in the middle range of X-ray power levels seen for other known solar system emission sources: auroral precipitation, solar X-ray scattering, and charge exchange (CXE) between solar wind (SW) ions and atmospheric neutrals. We eliminate auroral effects as a source, as Pluto has no known magnetic field and the NH/Alice UV spectrometer detected no airglow from Pluto during the flyby. Atmospheric haze particles could produce resonant scattering of solar X-rays from Pluto, but the energy signature of the detected photons does not match the solar spectrum and estimates of Pluto's scattered X-ray emission are 2 to 3 orders of magnitude lower than seen in our observations. CXE-driven emission from hydrogenic and heliogenic SW carbon, nitrogen, and oxygen ions can produce the energy signature seen, and the 6 x 1025 neutral gas escape rate from Pluto deduced from NH data (Gladstone et al. 2016) can support the 3.0 +3.0/-1.5 x 1024 X-ray photons/s emission rate required by our observations. Using the SW proton density and speed measured by the NH/SWAP instrument in the vicinity of Pluto at the time of the photon emissions, we find a

  18. A CHANDRA PERSPECTIVE ON GALAXY-WIDE X-RAY BINARY EMISSION AND ITS CORRELATION WITH STAR FORMATION RATE AND STELLAR MASS: NEW RESULTS FROM LUMINOUS INFRARED GALAXIES

    International Nuclear Information System (INIS)

    Lehmer, B. D.; Jenkins, L. P.; Alexander, D. M.; Goulding, A. D.; Roberts, T. P.; Bauer, F. E.; Brandt, W. N.; Ptak, A.

    2010-01-01

    We present new Chandra observations that complete a sample of seventeen (17) luminous infrared galaxies (LIRGs) with D H ∼ 20 cm -2 . The LIRGs in our sample have total infrared (8-1000 μm) luminosities in the range of L IR ∼ (1-8) x 10 11 L sun . The high-resolution imaging and X-ray spectral information from our Chandra observations allow us to measure separately X-ray contributions from active galactic nuclei and normal galaxy processes (e.g., X-ray binaries and hot gas). We utilized total infrared plus UV luminosities to estimate star formation rates (SFRs) and K-band luminosities and optical colors to estimate stellar masses (M * ) for the sample. Under the assumption that the galaxy-wide 2-10 keV luminosity (L gal HX ) traces the combined emission from high-mass X-ray binaries (HMXBs) and low-mass X-ray binaries, and that the power output from these components is linearly correlated with SFR and M * , respectively, we constrain the relation L gal HX = αM * + βSFR. To achieve this, we construct a Chandra-based data set composed of our new LIRG sample combined with additional samples of less actively star-forming normal galaxies and more powerful LIRGs and ultraluminous infrared galaxies (ULIRGs) from the literature. Using these data, we measure best-fit values of α = (9.05 ± 0.37) x 10 28 erg s -1 M -1 sun and β = (1.62 ± 0.22) x 10 39 erg s -1 (M sun yr -1 ) -1 . This scaling provides a more physically meaningful estimate of L gal HX , with ∼0.1-0.2 dex less scatter, than a direct linear scaling with SFR. Our results suggest that HMXBs dominate the galaxy-wide X-ray emission for galaxies with SFR/M * ∼>5.9 x 10 -11 yr -1 , a factor of ∼2.9 times lower than previous estimates. We find that several of the most powerful LIRGs and ULIRGs, with SFR/M * ∼> 10 -9 yr -1 , appear to be X-ray underluminous with respect to our best-fit relation. We argue that these galaxies are likely to contain X-ray binaries residing in compact star-forming regions

  19. X-ray emission line spectroscopy of cataclysmic variables. II. Temperatures and densities from line ratios in the Chandra HETG band

    International Nuclear Information System (INIS)

    Schlegel, E. M.; Shipley, H. V.; Rana, V. R.; Barrett, P. E.; Singh, K. P.

    2014-01-01

    We summarize the results of a line-by-line fitting analysis of the available spectra obtained using the Chandra High-Energy Transmission Grating. We confirm the existence of broad ionization and electron temperature ranges and high number densities in cataclysmic variables (CVs) of all subtypes. Temperatures range from ∼0.4 keV to ∼5-10 keV or more with a broad range detected in any given CV. In other words, single-temperature models do not describe the line emission. Number densities also cover a broad range, from 10 12 to >10 16 cm –3 . We demonstrate that much of the plasma is in a nonequilibrium state; the Fe emission, however, may arise from plasma in the ionization equilibrium.

  20. XV and XVI SERC Main Schools in Theoretical High Energy Physics held at the Saha Institute of Nuclear Physics and Harish-Chandra Research Institute

    CERN Document Server

    2005-01-01

    Current research in High Energy Physics focuses on a number of enigmatic issues that go beyond the very successful Standard Model of particle physics. Among these are the problem of neutrino mass, the (as yet) unobserved Higgs particle, the quark-gluon plasma, quantum aspects of gravity, and the so--called hierarchy problem. Satisfactory resolution of these important questions will take much research effort in both theory and experiment. The Science & Engineering Research Council, Department of Science & Technology has sponsored a series of SERC Schools in Theoretical High Energy Physics over the past several years, to provide instruction and training to graduate students working for research degrees. This book is an outcome of the schools held at the Saha Institute of Nuclear Physics, Kolkata in 2000, and at the Harish-Chandra Research Institute, Allahabad in 2001. Based on lectures by active researchers in the field---Rajiv Gavai, Debashis Ghoshal, Dileep Jatkar, Anjan Joshipura, Biswarup Mukhopadhy...

  1. IACHEC CROSS-CALIBRATION OF CHANDRA , NuSTAR , SWIFT , SUZAKU , XMM-NEWTON WITH 3C 273 ANDPKS 2155-304

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, Kristin K.; Forster, Karl [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Beardmore, Andrew P.; Page, Kim L. [X-ray and Observational Astronomy Group, Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Guainazzi, Matteo [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1, Yoshinodai, Sagamihara, Kanagawa, 252-5201 (Japan); Marshall, Herman L.; Miller, Eric D. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States); Stuhlinger, Martin [European Space Astronomy Centre (ESAC), P.O. Box 78, E-28691 Villanueva de la Caada, Madrid (Spain)

    2017-01-01

    On behalf of the International Astronomical Consortium for High Energy Calibration, we present results from the cross-calibration campaigns in 2012 on 3C 273 and in 2013 on PKS 2155-304 between the then active X-ray observatories Chandra , NuSTAR , Suzaku , Swift, and XMM-Newton . We compare measured fluxes between instrument pairs in two energy bands, 1–5 keV and 3–7 keV, and calculate an average cross-normalization constant for each energy range. We review known cross-calibration features and provide a series of tables and figures to be used for evaluating cross-normalization constants obtained from other observations with the above mentioned observatories.

  2. The 0.3-30 Kev Spectra Of Powerful Starburst Galaxies: Nustar And Chandra Observations Of Ngc 3256 And Ngc 3310

    DEFF Research Database (Denmark)

    Lehmer, B. D.; Tyler, J. B.; Hornschemeier, A. E.

    2015-01-01

    -law distributions with Γ ≈ 2.6 at E > 5-7 keV. Using new and archival Chandra data, we search for signatures of heavily obscured or low luminosity active galactic nuclei (AGNs). We find that both NGC 3256 and NGC 3310 have X-ray detected sources coincident with nuclear regions; however, the steep NuSTAR spectra...... observations therefore constrain the average spectral shape of galaxy-wide populations of luminous accreting binaries (i.e., ULXs). Interestingly, despite a completely different galaxy sample selection, emphasizing here a range of SFRs and stellar masses, these properties are similar to those of super...... likely explained by the relatively low metallicity of the young stellar population in this galaxy, a property that is expected to produce an excess of luminous X-ray binaries for a given SFR....

  3. High-redshift AGN in the Chandra Deep Fields: the obscured fraction and space density of the sub-L* population

    Science.gov (United States)

    Vito, F.; Brandt, W. N.; Yang, G.; Gilli, R.; Luo, B.; Vignali, C.; Xue, Y. Q.; Comastri, A.; Koekemoer, A. M.; Lehmer, B. D.; Liu, T.; Paolillo, M.; Ranalli, P.; Schneider, D. P.; Shemmer, O.; Volonteri, M.; Wang, J.

    2018-01-01

    We investigate the population of high-redshift (3 ≤ z active galactic nuclei (AGN) selected in the two deepest X-ray surveys, the 7 Ms Chandra Deep Field-South and 2 Ms Chandra Deep Field-North. Their outstanding sensitivity and spectral characterization of faint sources allow us to focus on the sub-L* regime (logLX ≲ 44), poorly sampled by previous works using shallower data, and the obscured population. Taking fully into account the individual photometric-redshift probability distribution functions, the final sample consists of ≈102 X-ray-selected AGN at 3 ≤ z 23 is ∼0.6-0.8, once incompleteness effects are taken into account, with no strong dependence on redshift or luminosity. We derived the high-redshift AGN number counts down to F0.5-2 keV = 7 × 10-18 erg cm-2 s-1, extending previous results to fainter fluxes, especially at z > 4. We put the tightest constraints to date on the low-luminosity end of AGN luminosity function at high redshift. The space density, in particular, declines at z > 3 at all luminosities, with only a marginally steeper slope for low-luminosity AGN. By comparing the evolution of the AGN and galaxy densities, we suggest that such a decline at high luminosities is mainly driven by the underlying galaxy population, while at low luminosities there are hints of an intrinsic evolution of the parameters driving nuclear activity. Also, the black hole accretion rate density and star formation rate density, which are usually found to evolve similarly at z ≲ 3, appear to diverge at higher redshifts.

  4. The Ultra-fast Outflow of the Quasar PG 1211+143 as Viewed by Time-averaged Chandra Grating Spectroscopy

    Science.gov (United States)

    Danehkar, Ashkbiz; Nowak, Michael A.; Lee, Julia C.; Kriss, Gerard A.; Young, Andrew J.; Hardcastle, Martin J.; Chakravorty, Susmita; Fang, Taotao; Neilsen, Joseph; Rahoui, Farid; Smith, Randall K.

    2018-02-01

    We present a detailed X-ray spectral study of the quasar PG 1211+143 based on Chandra High Energy Transmission Grating Spectrometer (HETGS) observations collected in a multi-wavelength campaign with UV data using the Hubble Space Telescope Cosmic Origins Spectrograph (HST-COS) and radio bands using the Jansky Very Large Array (VLA). We constructed a multi-wavelength ionizing spectral energy distribution using these observations and archival infrared data to create XSTAR photoionization models specific to the PG 1211+143 flux behavior during the epoch of our observations. Our analysis of the Chandra-HETGS spectra yields complex absorption lines from H-like and He-like ions of Ne, Mg, and Si, which confirm the presence of an ultra-fast outflow (UFO) with a velocity of approximately ‑17,300 km s‑1 (outflow redshift z out ∼ ‑0.0561) in the rest frame of PG 1211+143. This absorber is well described by an ionization parameter {log}ξ ∼ 2.9 {erg} {{{s}}}-1 {cm} and column density {log}{N}{{H}}∼ 21.5 {{cm}}-2. This corresponds to a stable region of the absorber’s thermal stability curve, and furthermore its implied neutral hydrogen column is broadly consistent with a broad Lyα absorption line at a mean outflow velocity of approximately ‑16,980 km s‑1 detected by our HST-COS observations. Our findings represent the first simultaneous detection of a UFO in both X-ray and UV observations. Our VLA observations provide evidence for an active jet in PG 1211+143, which may be connected to the X-ray and UV outflows; this possibility can be evaluated using very-long-baseline interferometric observations.

  5. X-ray Properties of the z ~ 4.5 Lyα Emitters in the Chandra Deep Field South Region

    Science.gov (United States)

    Zheng, Z. Y.; Wang, J. X.; Finkelstein, S. L.; Malhotra, S.; Rhoads, J. E.; Finkelstein, K. D.

    2010-07-01

    We report the first X-ray detection of Lyα emitters (LAEs) at redshift z ~ 4.5. One source (J033127.2-274247) is detected in the Extended Chandra Deep Field-South (ECDF-S) X-ray data and has been spectroscopically confirmed as a z = 4.48 quasar with LX = 4.2 × 1044 erg s-1. The single detection gives an Lyα quasar density of ~ 2.7+6.2 -2.2 × 10-6 Mpc-3, consistent with the X-ray luminosity function of quasars. Another 22 LAEs in the central Chandra Deep Field-South region are not detected individually, but their co-added counts yield an S/N = 2.4 (p = 99.83%) detection at soft band, with an effective exposure time of ~36 Ms. Further analysis of the equivalent width (EW) distribution shows that all the signals come from 12 LAE candidates with EWrestLAEs. If the average X-ray emission is due to star formation, it corresponds to a star formation rate (SFR) of 3%-10%. However, our upper limit on the SFR X is ~7 times larger than the upper limit on SFR X on z ~ 3.1 LAEs in the same field and at least 30 times higher than the SFR estimated from Lyα emission. From the average X-ray-to-Lyα line ratio, we estimate that fewer than 3.2% (6.3%) of our LAEs could be high-redshift type 1 (type 2) active galactic nuclei (AGNs) and those hidden AGNs likely show low rest-frame EWs.

  6. Testing the galaxy cluster mass-observable relations at z = 1 with XMM-Newton and Chandra observations of XLSSJ022403.9-041328

    Science.gov (United States)

    Maughan, B. J.; Jones, L. R.; Pierre, M.; Andreon, S.; Birkinshaw, M.; Bremer, M. N.; Pacaud, F.; Ponman, T. J.; Valtchanov, I.; Willis, J.

    2008-07-01

    We present an analysis of deep XMM-Newton and Chandra observations of the z = 1.05 galaxy cluster XLSSJ022403.9-041328 (hereafter XLSSC029), detected in the XMM-Newton Large Scale Structure survey. Density and temperature profiles of the X-ray emitting gas were used to perform a hydrostatic mass analysis of the system. This allowed us to measure the total mass and gas fraction in the cluster and define overdensity radii R500 and R2500. The global properties of XLSSC029 were measured within these radii and compared with those of the local population. The gas mass fraction was found to be consistent with local clusters. The mean metal abundance was 0.18+0.17-0.15Zsolar, with the cluster core regions excluded, consistent with the predicted and observed evolution. The properties of XLSSC029 were then used to investigate the position of the cluster on the M-kT, YX-M and LX-M scaling relations. In all cases the observed properties of XLSSC029 agreed well with the simple self-similar evolution of the scaling relations. This is the first test of the evolution of these relations at z > 1 and supports the use of the scaling relations in cosmological studies with distant galaxy clusters. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. E-mail: ben.maughan@bristol.ac.uk ‡ Chandra fellow.

  7. Development of fully depleted scientific CCDs for astronomy

    Science.gov (United States)

    Boggs, Kasey; Bredthauer, Richard; Lesser, Michael

    2007-02-01

    Due to aggressive scientific specifications, Semiconductor Technology Associates and the University of Arizona's Imaging Technology Laboratory have collaborated to develop a fully depleted back illuminated CCD for scientific imaging. These devices are designed to target increased quantum efficiency into the near-infrared, without reduction in the modulation transfer function, charge transfer efficiency, or rms noise. The STA1700 series imagers are back illuminated 100 micron thick devices with a 10 micron pixel pitch targeted to meet the requirements of the Large Synoptic Survey Telescope (LSST). Recent characterization results will be presented including the point spread function of a 2 micron spot. Also discussed will be the thinning and packaging developments for the STA1700. These efforts include the addition of a backside bias contact, invar package design with high density connectors, as well as etching and backside coating optimization for high resistivity silicon.

  8. Tracing the Mass-Dependent Star Formation History of Late-Type Galaxies using X-ray Emission: Results from the CHANDRA Deep Fields

    Science.gov (United States)

    Lehmer, B.D; Brandt, W.N.; Schneider, D.P.; Steffen, A.T.; Alexander, D.M.; Bell, E.F.; Hornschemeier, A.E.; McIntosh, D.H.; Bauer, F.E.; Gilli, R.; hide

    2008-01-01

    We report on the X-ray evolution over the last approx.9 Gyr of cosmic history (i.e., since z = 1.4) of late-type galaxy populations in the Chandra Deep Field-North and Extended Chandra Deep Field-South (CDF-N and E-CDF-S. respectively; jointly CDFs) survey fields. Our late-type galaxy sample consists of 2568 galaxies. which were identified using rest-frame optical colors and HST morphologies. We utilized X-ray stacking analyses to investigate the X-ray emission from these galaxies, emphasizing the contributions from normal galaxies that are not dominated by active galactic nuclei (AGNs). Over this redshift range, we find significant increases (factors of approx. 5-10) in the X-ray-to-optical mean luminosity ratio (L(sub x)/L(sub B)) and the X-ray-to-stellar-mass mean ratio (L(sub x)/M(sub *)) for galaxy populations selected by L(sub B) and M(sub *), respectively. When analyzing galaxy samples selected via SFR, we find that the mean X-ray-to-SFR ratio (L(sub x)/SFR) is consistent with being constant over the entire redshift range for galaxies with SFR = 1-100 Solar Mass/yr, thus demonstrating that X-ray emission can be used as a robust indicator of star-formation activity out to z approx. 1.4. We find that the star-formation activity (as traced by X-ray luminosity) per unit stellar mass in a given redshift bin increases with decreasing stellar mass over the redshift range z = 0.2-1, which is consistent with previous studies of how star-formation activity depends on stellar mass. Finally, we extend our X-ray analyses to Lyman break galaxies at z approx. 3 and estimate that L(sub x)/L(sub B) at z approx. 3 is similar to its value at z = 1.4.

  9. THE SOLUBILITY OF MILAS BAUXITE ORE IN SULPHURIC ACI

    Directory of Open Access Journals (Sweden)

    Mustafa GULFEN

    2001-06-01

    Full Text Available The effects of calcination conditions,sulphuric acid concentrations and dissolvingtemperature and period as parameters to thesolubility of the bauxite ore from Gobekdagı reservesin Mugla-Milas region were investigated. The bauxitesamples were calcined in different periods at differenttemperatures. Then the solubility of the calcinedbauxite samples in sulphuric acid solution wasexamined. Dissolving activation energy (Ea wascalculated using the optimum kinetics equation andthe results obtained from the solubility studiesexamined dissolving temperatures and periods

  10. Sindromi prenaprezanja u šaci, podlaktici i laktu

    OpenAIRE

    Bilić, Ranko; Kolundžić, Robert; Jelić, Mislav

    2002-01-01

    Primarna uloga čitavoga gornjeg ekstremiteta, tj. ramena, nadlaktice, lakta, podlaktice i ručnog zgloba jest postavljanje šake u prikladan položaj za obavljanje nekog rada, a kao krajnji dio ruke istodobno je i osjetni organ. Kompleksna anatomija šake izražava obje funkcije koje su temeljne u čovjekovoj komunikaciji s okolinom. Zbog toga vrlo su učestale akutne ozljede i kronična oštećenja (hrskavica, mišić, tetiva, kost ili živac), odnosno sindromi prenaprezanja u području šake i drugih dije...

  11. Animal computer interaction (ACI) & designing for animal interaction (AXD)

    DEFF Research Database (Denmark)

    Morrison, Ann Judith; Turner, Jane; Farley, Helen

    2017-01-01

    This workshop invites researchers and practitioners from HCI and related fields who work in some capacity with animals and who recognise the sentient nature of their being. We call for those who want to better understand how to work with animals and learn from them. We are a small team looking...... to build an Australian chapter of the Animal Computer Interaction Community. The workshop will elicit discussion, forge new partnerships and head up a new group on the state of the art within this field in Australia, including comparative international studies. For more information see http://www.ozaci.org/...

  12. Controlled low strength materials (CLSM), reported by ACI Committee 229

    International Nuclear Information System (INIS)

    Rajendran, N.

    1997-01-01

    Controlled low-strength material (CLSM) is a self-compacted, cementitious material used primarily as a backfill in lieu of compacted fill. Many terms are currently used to describe this material including flowable fill, unshrinkable fill, controlled density fill, flowable mortar, flowable fly ash, fly ash slurry, plastic soil-cement, soil-cement slurry, K-Krete and other various names. This report contains information on applications, material properties, mix proportioning, construction and quality-control procedures. This report's intent is to provide basic information on CLSM technology, with emphasis on CLSM material characteristics and advantages over conventional compacted fill. Applications include backfills, structural fills, insulating and isolation fills, pavement bases, conduit bedding, erosion control, void filling, and radioactive waste management

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

    Energy Technology Data Exchange (ETDEWEB)

    Jester, Sebastian; /Fermilab; Harris, D.E.; /Smithsonian Astrophys. Observ.; Marshall, H.L.; /MIT, MKI; 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.

  14. Deep Chandra Observations of ESO 428-G014. II. Spectral Properties and Morphology of the Large-scale Extended X-Ray Emission

    Science.gov (United States)

    Fabbiano, G.; Paggi, A.; Karovska, M.; Elvis, M.; Maksym, W. P.; Risaliti, G.; Wang, Junfeng

    2018-03-01

    We present a deep Chandra spectral and spatial study of the kpc-scale diffuse X-ray emission of the Compton-thick (CT) active galactic nucleus (AGN) ESO 428-G014. The entire spectrum is best fit with composite photoionization + thermal models. The diffuse emission is more extended at lower energies (cross-cone direction, where the AGN emission would be mostly obscured by the torus in the standard AGN model. Our results suggest that the transmission of the obscuring region in the cross-cone direction is ∼10% of that in the cone direction. In the 0.3–1.5 keV band, the ratio of cross-cone to cone photons increases to ∼84%, suggesting an additional soft diffuse emission component disjoint from the AGN. This could be due to hot ISM trapped in the potential of the galaxy. The luminosity of this component, ∼5 × 1038 erg s‑1, is roughly consistent with the thermal component suggested by the spectral fits in the 170–900 pc annulus.

  15. Erratum: "Photoionization Modeling of Oxygen K Absorption in the Interstellar Medium, the Chandra Grating Spectra of XTE J1817-330" (2013, Apj, 768, 60)

    Science.gov (United States)

    Gatuzz, E.; Garcia, J.; Mendoza, C.; Kallman, Timothy R.; Witthoeft, Michael C.; Lohfink, A.; Bautista, M. A.; Palmeri, P.; Quinet, P.

    2013-01-01

    In the published version of this paper, there are some minor inaccuracies in the absorption-line wavelengths listed in Table 4 as a result of a faulty reduction procedure of the Obs6615 spectrum. The shifts have been detected in a comparison with the wavelengths listed for this spectrum in the Chandra Transmission Grating Catalog and Archive (TGCat8). They are due to incorrect centroid positions of the zero-order image in both reductions as determined by the tgdetect utility which, when disentangled, yield the improved line positions of the amended Table 4 given below. It must also be pointed out that other quantitative findings of the original paper: 1. Table 5, p. 9: the column density (NH), ionization parameter, oxygen abundance of the warmabs model and the normalization and photon index of the power-law model; 2. Table 6, p. 9: the hydrogen column density of the warmabs fit; 3. Table 7, p. 9: the present oxygen equivalent widths of XTE J1817-330; and 4. Table 8, p. 10: the present oxygen column densities of XTE J1817-330 derived from both the curve of growth and warmabs model fit have been revised in the new light and are, within the estimated uncertainty ranges, in good accord with the new rendering.

  16. XMM-Newton and Chandra Observations of the Remarkable Dynamics of the Intracluster Medium and Radio Sources in the Clusters Abell 2061 and 3667

    Science.gov (United States)

    Sarazin, C.; Hogge, T.; Chatzikos, M.; Wik, D.; Giacintucci, S.; Clarke, T.; Wong, K.; Gitti, M.; Finoguenov, A.

    2014-07-01

    XMM-Newton and Chandra observations of remarkable dynamic structures in the X-ray gas and connected radio sources in three clusters are presented. Abell 2061 is a highly irregular, merging cluster in the Corona Borealis supercluster. X-ray observations show that there is a plume of very cool gas (˜1 keV) to the NE of the cluster, and a hot (7.6 keV) shock region just NE of the center. There is a very bright radio relic to the far SW of the cluster, and a central radio halo/relic with an extension to the NE. Comparison to SLAM simulations show that this is an offset merger of a ˜5 × 10^{13} M⊙ subcluster with a ˜2.5 × 10^{14} M⊙ cluster seen after first core passage. The plume is the cool-core gas from the subcluster, which has been ``slingshot'' to the NE of the cluster. The plume gas is now falling back into the cluster center, and shocks when it hits the central gas. The model predicts a strong shock to the SW at the location of the bright radio relic, and another shock at the NE radio extension. Time permitting, the observations of Abell 2626 and Abell 3667 will also be presented.

  17. Black hole growth and starburst activity at z = 0.6-4 in the Chandra Deep Field South. Host galaxies properties of obscured AGN

    Science.gov (United States)

    Brusa, M.; Fiore, F.; Santini, P.; Grazian, A.; Comastri, A.; Zamorani, G.; Hasinger, G.; Merloni, A.; Civano, F.; Fontana, A.; Mainieri, V.

    2009-12-01

    Aims: The co-evolution of host galaxies and the active black holes which reside in their centre is one of the most important topics in modern observational cosmology. Here we present a study of the properties of obscured active galactic nuclei (AGN) detected in the CDFS 1 Ms observation and their host galaxies. Methods: We limited the analysis to the MUSIC area, for which deep K-band observations obtained with ISAAC@VLT are available, ensuring accurate identifications of the counterparts of the X-ray sources as well as reliable determination of photometric redshifts and galaxy parameters, such as stellar masses and star formation rates. In particular, we: 1) refined the X-ray/infrared/optical association of 179 sources in the MUSIC area detected in the Chandra observation; 2) studied the host galaxies observed and rest frame colors and properties. Results: We found that X-ray selected (LX ⪆ 1042 erg s-1) AGN show Spitzer colors consistent with both AGN and starburst dominated infrared continuum; the latter would not have been selected as AGN from infrared diagnostics. The host galaxies of X-ray selected obscured AGN are all massive (Mast > 1010 M_⊙) and, in 50% of the cases, are also actively forming stars (1/SSFR 1 and Mast > 3 × 1011 M_⊙, a fraction significantly higher than in the local Universe for AGN of similar luminosities. Tables [see full textsee full textsee full text] and [see full textsee full textsee full text] are only available in electronic form at http://www.aanda.org

  18. Tracing the accretion history of supermassive black holes through X-ray variability: results from the ChandraDeep Field-South

    Science.gov (United States)

    Paolillo, M.; Papadakis, I.; Brandt, W. N.; Luo, B.; Xue, Y. Q.; Tozzi, P.; Shemmer, O.; Allevato, V.; Bauer, F. E.; Comastri, A.; Gilli, R.; Koekemoer, A. M.; Liu, T.; Vignali, C.; Vito, F.; Yang, G.; Wang, J. X.; Zheng, X. C.

    2017-11-01

    We study the X-ray variability properties of distant active galactic nuclei (AGNs) in the ChandraDeep Field-South region over 17 yr, up to z ˜ 4, and compare them with those predicted by models based on local samples. We use the results of Monte Carlo simulations to account for the biases introduced by the discontinuous sampling and the low-count regime. We confirm that variability is a ubiquitous property of AGNs, with no clear dependence on the density of the environment. The variability properties of high-z AGNs, over different temporal time-scales, are most consistent with a power spectral density (PSD) described by a broken (or bending) power law, similar to nearby AGNs. We confirm the presence of an anticorrelation between luminosity and variability, resulting from the dependence of variability on black hole (BH) mass and accretion rate. We explore different models, finding that our acceptable solutions predict that BH mass influences the value of the PSD break frequency, while the Eddington ratio λEdd affects the PSD break frequency and, possibly, the PSD amplitude as well. We derive the evolution of the average λEdd as a function of redshift, finding results in agreement with measurements based on different estimators. The large statistical uncertainties make our results consistent with a constant Eddington ratio, although one of our models suggest a possible increase of λEdd with lookback time up to z ˜ 2-3. We conclude that variability is a viable mean to trace the accretion history of supermassive BHs, whose usefulness will increase with future, wide-field/large effective area X-ray missions.

  19. SUDARE-VOICE variability-selection of active galaxies in the Chandra Deep Field South and the SERVS/SWIRE region

    Science.gov (United States)

    Falocco, S.; Paolillo, M.; Covone, G.; De Cicco, D.; Longo, G.; Grado, A.; Limatola, L.; Vaccari, M.; Botticella, M. T.; Pignata, G.; Cappellaro, E.; Trevese, D.; Vagnetti, F.; Salvato, M.; Radovich, M.; Hsu, L.; Capaccioli, M.; Napolitano, N.; Brandt, W. N.; Baruffolo, A.; Cascone, E.; Schipani, P.

    2015-07-01

    Context. One of the most peculiar characteristics of active galactic nuclei (AGNs) is their variability over all wavelengths. This property has been used in the past to select AGN samples and is foreseen to be one of the detection techniques applied in future multi-epoch surveys, complementing photometric and spectroscopic methods. Aims: In this paper, we aim to construct and characterise an AGN sample using a multi-epoch dataset in the r band from the SUDARE-VOICE survey. Methods: Our work makes use of the VST monitoring programme of an area surrounding the Chandra Deep Field South to select variable sources. We use data spanning a six-month period over an area of 2 square degrees, to identify AGN based on their photometric variability. Results: The selected sample includes 175 AGN candidates with magnitude r< 23 mag. We distinguish different classes of variable sources through their lightcurves, as well as X-ray, spectroscopic, SED, optical, and IR information overlapping with our survey. Conclusions: We find that 12% of the sample (21/175) is represented by supernovae (SN). Of the remaining sources, 4% (6/154) are stars, while 66% (102/154) are likely AGNs based on the available diagnostics. We estimate an upper limit to the contamination of the variability selected AGN sample ≃34%, but we point out that restricting the analysis to the sources with available multi-wavelength ancillary information, the purity of our sample is close to 80% (102 AGN out of 128 non-SN sources with multi-wavelength diagnostics). Our work thus confirms the efficiency of the variability selection method, in agreement with our previous work on the COSMOS field. In addition we show that the variability approach is roughly consistent with the infrared selection.

  20. Late-Time Evolution of Composite Supernova Remnants: Deep Chandra Observations and Hydrodynamical Modeling of a Crushed Pulsar Wind Nebula in SNR G327.1-1.1

    Science.gov (United States)

    Temim, Tea; Slane, Patrick; Kolb, Christopher; Blondin, John; Hughes, John P.; Bucciantini, Niccolo

    2015-01-01

    In an effort to better understand the evolution of composite supernova remnants (SNRs) and the eventual fate of relativistic particles injected by their pulsars, we present a multifaceted investigation of the interaction between a pulsar wind nebula (PWN) and its host SNR G327.1-1.1. Our 350 ks Chandra X-ray observations of SNR G327.1-1.1 reveal a highly complex morphology; a cometary structure resembling a bow shock, prong-like features extending into large arcs in the SNR interior, and thermal emission from the SNR shell. Spectral analysis of the non-thermal emission offers clues about the origin of the PWN structures, while enhanced abundances in the PWN region provide evidence for mixing of supernova ejecta with PWN material. The overall morphology and spectral properties of the SNR suggest that the PWN has undergone an asymmetric interaction with the SNR reverse shock(RS) that can occur as a result of a density gradient in the ambient medium and or a moving pulsar that displaces the PWN from the center of the remnant. We present hydrodynamical simulations of G327.1-1.1 that show that its morphology and evolution can be described by a approx. 17,000 yr old composite SNR that expanded into a density gradient with an orientation perpendicular to the pulsar's motion. We also show that the RSPWN interaction scenario can reproduce the broadband spectrum of the PWN from radio to gamma-ray wavelengths. The analysis and modeling presented in this work have important implications for our general understanding of the structure and evolution of composite SNRs.

  1. An ALMA survey of submillimeter galaxies in the extended Chandra deep field south: The redshift distribution and evolution of submillimeter galaxies

    International Nuclear Information System (INIS)

    Simpson, J. M.; Swinbank, A. M.; Smail, Ian; Alexander, D. M.; Danielson, A. L. R.; Thomson, A. P.; Brandt, W. N.; Bertoldi, F.; Karim, A.; De Breuck, C.; Chapman, S. C.; Coppin, K. E. K.; Da Cunha, E.; Hodge, J. A.; Schinnerer, E.; Dannerbauer, H.; Greve, T. R.; Ivison, R. J.; Knudsen, K. K.; Poggianti, B. M.

    2014-01-01

    We present the first photometric redshift distribution for a large sample of 870 μm submillimeter galaxies (SMGs) with robust identifications based on observations with ALMA. In our analysis we consider 96 SMGs in the Extended Chandra Deep Field South, 77 of which have 4-19 band photometry. We model the SEDs for these 77 SMGs, deriving a median photometric redshift of z phot = 2.3 ± 0.1. The remaining 19 SMGs have insufficient photometry to derive photometric redshifts, but a stacking analysis of Herschel observations confirms they are not spurious. Assuming that these SMGs have an absolute H-band magnitude distribution comparable to that of a complete sample of z ∼ 1-2 SMGs, we demonstrate that they lie at slightly higher redshifts, raising the median redshift for SMGs to z phot = 2.5 ± 0.2. Critically we show that the proportion of galaxies undergoing an SMG-like phase at z ≥ 3 is at most 35% ± 5% of the total population. We derive a median stellar mass of M * = (8 ± 1) × 10 10 M ☉ , although there are systematic uncertainties of up to 5 × for individual sources. Assuming that the star formation activity in SMGs has a timescale of ∼100 Myr, we show that their descendants at z ∼ 0 would have a space density and M H distribution that are in good agreement with those of local ellipticals. In addition, the inferred mass-weighted ages of the local ellipticals broadly agree with the look-back times of the SMG events. Taken together, these results are consistent with a simple model that identifies SMGs as events that form most of the stars seen in the majority of luminous elliptical galaxies at the present day.

  2. X-Ray Spectral Analyses of AGNs from the 7Ms Chandra Deep Field-South Survey: The Distribution, Variability, and Evolutions of AGN Obscuration

    Science.gov (United States)

    Liu, Teng; Tozzi, Paolo; Wang, Jun-Xian; Brandt, William N.; Vignali, Cristian; Xue, Yongquan; Schneider, Donald P.; Comastri, Andrea; Yang, Guang; Bauer, Franz E.; Paolillo, Maurizio; Luo, Bin; Gilli, Roberto; Wang, Q. Daniel; Giavalisco, Mauro; Ji, Zhiyuan; Alexander, David M.; Mainieri, Vincenzo; Shemmer, Ohad; Koekemoer, Anton; Risaliti, Guido

    2017-09-01

    We present a detailed spectral analysis of the brightest active galactic nuclei (AGNs) identified in the 7Ms Chandra Deep Field-South (CDF-S) survey over a time span of 16 years. Using a model of an intrinsically absorbed power-law plus reflection, with possible soft excess and narrow Fe Kα line, we perform a systematic X-ray spectral analysis, both on the total 7Ms exposure and in four different periods with lengths of 2-21 months. With this approach, we not only present the power-law slopes, column densities {N}{{H}}, observed fluxes, and absorption-corrected 2-10 keV luminosities L X for our sample of AGNs, but also identify significant spectral variabilities among them on timescales of years. We find that the {N}{{H}} variabilities can be ascribed to two different types of mechanisms, either flux-driven or flux-independent. We also find that the correlation between the narrow Fe line EW and {N}{{H}} can be well explained by the continuum suppression with increasing {N}{{H}}. Accounting for the sample incompleteness and bias, we measure the intrinsic distribution of {N}{{H}} for the CDF-S AGN population and present reselected subsamples that are complete with respect to {N}{{H}}. The {N}{{H}}-complete subsamples enable us to decouple the dependences of {N}{{H}} on L X and on redshift. Combining our data with those from C-COSMOS, we confirm the anticorrelation between the average {N}{{H}} and L X of AGN, and find a significant increase of the AGN-obscured fraction with redshift at any luminosity. The obscured fraction can be described as {f}{obscured}≈ 0.42 {(1+z)}0.60.

  3. The Evolution of Normal Galaxy X-Ray Emission Through Cosmic History: Constraints from the 6 MS Chandra Deep Field-South

    Science.gov (United States)

    Lehmer, B. D.; Basu-Zych, A. R.; Mineo, S.; Brandt, W. N.; Eurfrasio, R. T.; Fragos, T.; Hornschemeier, A. E.; Lou, B.; Xue, Y. Q.; Bauer, F. E.; hide

    2016-01-01

    We present measurements of the evolution of normal-galaxy X-ray emission from z (is) approx. 0-7 using local galaxies and galaxy samples in the approx. 6 Ms Chandra Deep Field-South (CDF-S) survey. The majority of the CDF-S galaxies are observed at rest-frame energies above 2 keV, where the emission is expected to be dominated by X-ray binary (XRB) populations; however, hot gas is expected to provide small contributions to the observed-frame (is) less than 1 keV emission at z (is) less than 1. We show that a single scaling relation between X-ray luminosity (L(sub x)) and star-formation rate (SFR) literature, is insufficient for characterizing the average X-ray emission at all redshifts. We establish that scaling relations involving not only SFR, but also stellar mass and redshift, provide significantly improved characterizations of the average X-ray emission from normal galaxy populations at z (is) approx. 0-7. We further provide the first empirical constraints on the redshift evolution of X-ray emission from both low-mass XRB (LMXB) and high-mass XRB (HMXB) populations and their scalings with stellar mass and SFR, respectively. We find L2 -10 keV(LMXB)/stellar mass alpha (1+z)(sub 2-3) and L2 -10 keV(HMXB)/SFR alpha (1+z), and show that these relations are consistent with XRB population-synthesis model predictions, which attribute the increase in LMXB and HMXB scaling relations with redshift as being due to declining host galaxy stellar ages and metallicities, respectively. We discuss how emission from XRBs could provide an important source of heating to the intergalactic medium in the early universe, exceeding that of active galactic nuclei.

  4. The 4 Ms CHANDRA Deep Field-South Number Counts Apportioned by Source Class: Pervasive Active Galactic Nuclei and the Ascent of Normal Galaxies

    Science.gov (United States)

    Lehmer, Bret D.; Xue, Y. Q.; Brandt, W. N.; Alexander, D. M.; Bauer, F. E.; Brusa, M.; Comastri, A.; Gilli, R.; Hornschemeier, A. E.; Luo, B.; hide

    2012-01-01

    We present 0.5-2 keV, 2-8 keV, 4-8 keV, and 0.5-8 keV (hereafter soft, hard, ultra-hard, and full bands, respectively) cumulative and differential number-count (log N-log S ) measurements for the recently completed approx. equal to 4 Ms Chandra Deep Field-South (CDF-S) survey, the deepest X-ray survey to date. We implement a new Bayesian approach, which allows reliable calculation of number counts down to flux limits that are factors of approx. equal to 1.9-4.3 times fainter than the previously deepest number-count investigations. In the soft band (SB), the most sensitive bandpass in our analysis, the approx. equal to 4 Ms CDF-S reaches a maximum source density of approx. equal to 27,800 deg(sup -2). By virtue of the exquisite X-ray and multiwavelength data available in the CDF-S, we are able to measure the number counts from a variety of source populations (active galactic nuclei (AGNs), normal galaxies, and Galactic stars) and subpopulations (as a function of redshift, AGN absorption, luminosity, and galaxy morphology) and test models that describe their evolution. We find that AGNs still dominate the X-ray number counts down to the faintest flux levels for all bands and reach a limiting SB source density of approx. equal to 14,900 deg(sup -2), the highest reliable AGN source density measured at any wavelength. We find that the normal-galaxy counts rise rapidly near the flux limits and, at the limiting SB flux, reach source densities of approx. equal to 12,700 deg(sup -2) and make up 46% plus or minus 5% of the total number counts. The rapid rise of the galaxy counts toward faint fluxes, as well as significant normal-galaxy contributions to the overall number counts, indicates that normal galaxies will overtake AGNs just below the approx. equal to 4 Ms SB flux limit and will provide a numerically significant new X-ray source population in future surveys that reach below the approx. equal to 4 Ms sensitivity limit. We show that a future approx. equal to 10 Ms CDF

  5. THE MEGASECOND CHANDRA X-RAY VISIONARY PROJECT OBSERVATION OF NGC 3115. III. LUMINOSITY FUNCTIONS OF LMXBS AND DEPENDENCE ON STELLAR ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Dacheng; Irwin, Jimmy A. [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States); Wong, Ka-Wah [Eureka Scientific, Inc., 2452 Delmer Street Suite 100, Oakland, CA 94602-3017 (United States); Jennings, Zachary G.; Romanowsky, Aaron J.; Brodie, Jean P. [University of California Observatories, Santa Cruz, CA 95064 (United States); Homan, Jeroen; Remillard, Ronald A. [MIT Kavli Institute for Astrophysics and Space Research, MIT, 70 Vassar Street, Cambridge, MA 02139-4307 (United States); Strader, Jay [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, MI 48824 (United States); Sivakoff, Gregory R., E-mail: dacheng.lin@unh.edu [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1 (Canada)

    2015-07-20

    We studied the X-ray luminosity function (XLF) of low-mass X-ray binaries (LMXBs) in the nearby lenticular galaxy NGC 3115, using the Megasecond Chandra X-ray Visionary Project Observation. With a total exposure time of ∼1.1 Ms, we constructed the XLF down to a limiting luminosity of ∼10{sup 36} erg s{sup −1}, which is much deeper than that typically reached for other early-type galaxies. We found significant flattening of the overall LMXB XLF from dN/dL ∝ L{sup −2.2±0.4} above 5.5 × 10{sup 37} erg s{sup −1} to dN/dL ∝ L{sup −1.0±0.1} below it, although we could not rule out a fit with a higher break at ∼1.6 × 10{sup 38} erg s{sup −1}. We also found evidence that the XLF of LMXBs in globular clusters (GCs) is overall flatter than that of field LMXBs. Thus, our results for this galaxy do not support the idea that all LMXBs are formed in GCs. The XLF of field LMXBs seems to show spatial variation, with the XLF in the inner region of the galaxy being flatter than that in the outer region, probably due to contamination of LMXBs from undetected and/or disrupted GCs in the inner region. The XLF in the outer region is probably the XLF of primordial field LMXBs, exhibiting dN/dL ∝ L{sup −1.2±0.1} up to a break close to the Eddington limit of neutron star LMXBs (∼1.7 × 10{sup 38} erg s{sup −1}). The break of the GC LMXB XLF is lower, at ∼1.1 × 10{sup 37} erg s{sup −1}. We also confirm previous findings that the metal-rich/red GCs are more likely to host LMXBs than the metal-poor/blue GCs, which is more significant for more luminous LMXBs, and that more massive GCs are more likely to host LMXBs.

  6. NEAR-INFRARED COUNTERPARTS TO CHANDRA X-RAY SOURCES TOWARD THE GALACTIC CENTER. I. STATISTICS AND A CATALOG OF CANDIDATES

    International Nuclear Information System (INIS)

    Mauerhan, J. C.; Muno, M. P.; Morris, M. R.; Bauer, F. E.; Nishiyama, S.; Nagata, T.

    2009-01-01

    We present a catalog of 5184 candidate infrared counterparts to X-ray sources detected toward the Galactic center. The X-ray sample contains 9017 point sources detected in this region by the Chandra X-ray Observatory during the past decade, including data from a recent deep survey of the central 2 0 x 0. 0 8 of the Galactic plane. A total of 6760 of these sources have hard X-ray colors, and the majority of them lie near the Galactic center, while most of the remaining 2257 soft X-ray sources lie in the foreground. We cross-correlated the X-ray source positions with the 2MASS and SIRIUS near-infrared catalogs, which collectively contain stars with a 10σ limiting flux of K s ≤ 15.6 mag. In order to distinguish absorbed infrared sources near the Galactic center from those in the foreground, we defined red and blue sources as those which have H - K s ≥ 0.9 and <0.9 mag, respectively. We find that 5.8% ± 1.5% (2σ) of the hard X-ray sources have real infrared counterparts, of which 228 ± 99 are red and 166 ± 27 are blue. The red counterparts are probably comprised of Wolf-Rayet and O stars, high-mass X-ray binaries, and symbiotic binaries located near the Galactic center. Foreground X-ray binaries suffering intrinsic X-ray absorption could be included in the sample of blue infrared counterparts to hard X-ray sources. We also find that 39.4% ± 1.0% of the soft X-ray sources have blue infrared counterparts; most of these are probably coronally active dwarfs in the foreground. There is a noteworthy collection of ∼20 red counterparts to hard X-ray sources near the Sagittarius B H II region, which are probably massive binaries that have formed within the last several Myr. For each of the infrared matches to X-ray sources in our catalog we derived the probability that the association is real, based on the source properties and the results of the cross-correlation analysis. These data are included in our catalog and will serve spectroscopic surveys to identify

  7. Prafulla Chandra Rây

    Indian Academy of Sciences (India)

    This in tum led him to illumine the little known general chemistry of nitrites and hyponitrites. This endeavour was spread over all his years in .... Nature magazine of July 15 wrote, "Sir Prafulla was more than anyone else, responsible for the great development of scientific research in India during the past fifty years ... '.

  8. Properties and morphologies of Lyman break galaxies at z ˜ 1 in the Chandra Deep Field South, inferred from spectral energy distributions

    Science.gov (United States)

    Chen, Z.; Shu, C. G.; Burgarella, D.; Buat, V.; Huang, J.-S.; Luo, Z. J.

    2013-05-01

    After carefully cross-identifying previously discovered - and selected by the Galaxy Evolution Explorer (GALEX) - Lyman break galaxy (LBG) candidates one-to-one with their optical counterparts in the field of the Chandra Deep Field South (CDF-S), we re-estimate their photometric redshifts using multiwavelength data from ultraviolet and optical to near-infrared. Considering their re-estimated photometric redshifts and spectral energy distributions, we refine a new updated sample of 383 LBGs at 0.7 ≲ z ≲ 1.4, with two confirmed active galactic nuclei being excluded. There are 260 and 111 LBGs classified as starburst and irregular types, respectively. The ages of the LBGs span from several Myr to 1.5 Gyr with a median of ˜50 Myr. Their dust-corrected star formation rates (SFRs) and stellar masses (M*) are 4-220 M⊙ yr-1 and from 2.3 × 108 to 4 × 1011 M⊙, with median values of ˜25 M⊙ yr-1 and ˜1010 M⊙. The rest-frame far-ultraviolet luminosity function of the LBGs is presented with the best-fitting Schechter parameters of α = -1.61 ± 0.40, M* = -20.40 ± 0.22 and φ* = (0.89 ± 0.30) × 10-3 Mpc-3 dex-1. LBGs of irregular types are mainly distributed along the main sequence of star-forming galaxies, while most LBGs of starburst types are located in the starburst region. Together with previous studies, we suggest that the star formation mode for LBGs at z > 3 is mainly starburst, and that it evolves to be more significant to the quenching mode after z ˜ 3. A downsizing effect is clearly found, and we discuss the physical implications and comparisons with previous studies in detail. LBGs with larger SFRs are, on average, more compact. In the rest-frame colour (U - B)-M* diagram, LBGs are distributed in the `blue' cloud. We suggest that LBGs might evolve along the blue cloud from later to earlier types. The Hubble Space Telescope images in F606W (V band) and F850LP (z band) are taken from the Galaxy Evolution from Morphology and SEDs (GEMS) survey and

  9. The 2-79 keV X-ray spectrum of the circinus galaxy with NuSTAR, XMM-Newton, and Chandra: a fully compton-thick active galactic nucleus

    DEFF Research Database (Denmark)

    Arévalo, P.; Bauer, F. E.; Puccetti, S.

    2014-01-01

    The Circinus galaxy is one of the closest obscured active galactic nuclei (AGNs), making it an ideal target for detailed study. Combining archival Chandra and XMM-Newton data with new NuSTAR observations, we model the 2-79 keV spectrum to constrain the primary AGN continuum and to derive physical...... by an optically thick torus, where the intrinsic spectrum is a power law of photon index Γ = 2.2-2.4, the torus has an equatorial column density of NH = (6-10) × 1024 cm-2, and the intrinsic AGN 2-10 keV luminosity is (2.3-5.1) × 1042 erg s-1. These values place Circinus along the same relations as unobscured...

  10. A Chandra Observation of the Ultraluminous Infrared Galaxy IRAS 19254-7245 (The Superantennae): X-Ray Emission from the Compton-Thick Active Galactic Nucleus and the Diffuse Starburst

    Science.gov (United States)

    Jia, Jianjun; Ptak, Andrew; Heckman, Timothy M.; Braito, Valentina; Reeves, James

    2012-01-01

    We present a Chandra observation of IRAS 19254-7245, a nearby ultraluminous infrared galaxy also known as the Superantennae. The high spatial resolution of Chandra allows us to disentangle for the first time the diffuse starburst (SB) emission from the embedded Compton-thick active galactic nucleus (AGN) in the southern nucleus. No AGN activity is detected in the northern nucleus. The 2-10 keV spectrum of the AGN emission is fitted by a flat power law (TAU = 1.3) and an He-like Fe Kalpha line with equivalent width 1.5 keV, consistent with previous observations. The Fe K line profile could be resolved as a blend of a neutral 6.4 keV line and an ionized 6.7 keV (He-like) or 6.9 keV (H-like) line. Variability of the neutral line is detected compared with the previous XMM-Newton and Suzaku observations, demonstrating the compact size of the iron line emission. The spectrum of the galaxy-scale extended emission excluding the AGN and other bright point sources is fitted with a thermal component with a best-fit kT of approximately 0.8 keV. The 2-10 keV luminosity of the extended emission is about one order of magnitude lower than that of the AGN. The basic physical and structural properties of the extended emission are fully consistent with a galactic wind being driven by the SB. A candidate ultraluminous X-ray source is detected 8 south of the southern nucleus. The 0.3 - 10 keV luminosity of this off-nuclear point source is approximately 6 x 10(exp 40) erg per second if the emission is isotropic and the source is associated with the Superantennae.

  11. New Constraints on the Geometry and Kinematics of Matter Surrounding the Accretion Flow in X-Ray Binaries from Chandra High-energy Transmission Grating X-Ray Spectroscopy

    Science.gov (United States)

    Tzanavaris, P.; Yaqoob, T.

    2018-03-01

    The narrow, neutral Fe Kα fluorescence emission line in X-ray binaries (XRBs) is a powerful probe of the geometry, kinematics, and Fe abundance of matter around the accretion flow. In a recent study it has been claimed, using Chandra High-Energy Transmission Grating (HETG) spectra for a sample of XRBs, that the circumnuclear material is consistent with a solar-abundance, uniform, spherical distribution. It was also claimed that the Fe Kα line was unresolved in all cases by the HETG. However, these conclusions were based on ad hoc models that did not attempt to relate the global column density to the Fe Kα line emission. We revisit the sample and test a self-consistent model of a uniform, spherical X-ray reprocessor against HETG spectra from 56 observations of 14 Galactic XRBs. We find that the model is ruled out in 13/14 sources because a variable Fe abundance is required. In two sources a spherical distribution is viable, but with nonsolar Fe abundance. We also applied a solar-abundance Compton-thick reflection model, which can account for the spectra that are inconsistent with a spherical model, but spectra with a broader bandpass are required to better constrain model parameters. We also robustly measured the velocity width of the Fe Kα line and found FWHM values of up to ∼5000 km s‑1. Only in some spectra was the Fe Kα line unresolved by the HETG.

  12. Latest Concrete Engineering. Fourth CANMET/ACI/JCI International Conference (2); Saikin no konkurito kougaku. CANMET/ACI/JCI dai 4 kai kokusai kaigi yori (2)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-10

    Daimon and Sakai (Tokyo Institute of Technology) spoke on the limestone powder related to reaction and rheology, describing that stone powder facilitates the manufacturing of high fluidity concrete, and referred to the reaction between C3A and gypsum. Akman (Turkey) spoke on the application of zeolite aggregate and bentonite to the mortar for radioactive waste solidification, referring to the their effectiveness for Co and Ce. Sato (Utsunomiya Univ.) spoke on the latest concrete pavement technology, introducing PC pavement and continuous RC pavement including repairing method. Collepardi (Italy) spoke on the long-term durability of RC construction, pointing out the importance of the corrosion prevention of reinforcing steel for the purpose of durability securing, improvement of tensile strength and fragility, and coating on cover reinforcement for prevention of cracking at a covered face. (translated by NEDO)

  13. Fourth CANMET/ACI/JCI International Conference. Durability (17); CANMET/ACI/JCI dai 4 kai kokusai kaigi yori. Taikyusei (17)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-10

    Kawaguchi (Muramoto Construction) and others studied on durability of high volume fly ash concrete, and reported that it had the same freezing damage resistance as ordinary concrete, and wear resistance, anti-sea water corrosion, water tightness were improved. Nwaubani (Great Britain) and others investigated on the effect of cement type and permeable form on salt permeability resistance, and showed the effect of metakaolin and fly ash. Furusawa (Kajima Corporation) and others investigated on damage conditions of 15-year old RC dock, and proposed a prediction model for remaining service life. Taheri (New Zealand) and others examined on durability of oceanic concrete subject to repetition of dry wet and temperature variation, and reported that variations of temperature and humidity remarkably accelerated salt infiltration. (translated by NEDO)

  14. An automated system to measure the quantum efficiency of CCDs for astronomy

    Science.gov (United States)

    Coles, R.; Chiang, J.; Cinabro, D.; Haupt, J.; Neal, H.; Nomerotski, A.; Takacs, P.

    2017-04-01

    We describe a system to measure the Quantum Efficiency in the wavelength range of 300 nm to 1100 nm of 40 × 40 mm n-channel CCD sensors for the construction of the 3.2 gigapixel LSST focal plane. The technique uses a series of instrument to create a very uniform flux of photons of controllable intensity in the wavelength range of interest across the face the sensor. This allows the absolute Quantum Efficiency to be measured with an accuracy in the 1% range. This system will be part of a production facility at Brookhaven National Lab for the basic component of the LSST camera.

  15. X-ray analysis of fully depleted CCDs with small pixel size

    Czech Academy of Sciences Publication Activity Database

    Kotov, I.V.; Haupt, J.; Kubánek, Petr; O'Connor, P.; Takacs, P.

    2015-01-01

    Roč. 787, Jul (2015), s. 12-19 ISSN 0168-9002 Institutional support: RVO:68378271 Keywords : charge diffusion * Charge transfer efficiency * CTE * CCD Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 1.200, year: 2015

  16. Characterization and Processing of Non-Uniformities in Back-Illuminated CCDs

    Science.gov (United States)

    Lemm, Alia D.; Della-Rose, Devin J.; Maddocks, Sally

    2018-01-01

    In astronomical photometry, Charged Coupled Device (CCD) detectors are used to achieve high precision photometry and must be properly calibrated to correct for noise and pixel non-uniformities. Uncalibrated images may contain bias offset, dark current, bias structure and uneven illumination. In addition, standard data reduction is often not sufficient to “normalize” imagery to single-digit millimagnitude (mmag) precision. We are investigating an apparent non-uniformity, or interference pattern, in a back-illuminated sensor, the Alta U-47, attached to a DFM Engineering 41-cm Ritchey-Chrétien f/8 telescope. Based on the amplitude of this effect, we estimate that instrument magnitude peak-to-valley deviations of 50 mmag or more may result. Our initial testing strongly suggests that reflected skylight from high pressure sodium city lights may be the cause of this interference pattern. Our research goals are twofold: to fully characterize this non-uniformity and to determine the best method to remove this interference pattern from our reduced CCD images.

  17. Exploration of X-ray and charged-particle spectroscopy with CCDs and PSDs

    International Nuclear Information System (INIS)

    Simons, D.P.L.; Mutsaers, P.H.A.; Ijzendoorn, L.J. van; Voigt, M.J.A. de

    1998-01-01

    Two alternative detector types have been studied for use in the Eindhoven scanning ion microprobe set-up. First, the applicability of a charge coupled device (CCD) system for X-ray spectroscopy has been explored. Second, some properties of the SiTek type 1L30 position sensitive detector (PSD) for charged-particle spectroscopy have been studied. A literature survey shows that excellent X-ray spectroscopy with a CCD system is feasible, particularly with a deep-depletion backside-illuminated CCD and low speed read-out. If, however, high-speed CCD read-out is required, such as for scanning microprobe experiments, a CCD system cannot be used for spectroscopy due to excess read-out noise. For the PSD, noise theory calculations are presented, which result in a noise shaping time for optimal energy and position resolution. In practice, however, a much longer time is needed to obtain sufficient energy and position linearity. Characterization measurements of the PSD using our 4 MeV He + microprobe are also described. A position resolution of 0.47 mm and a position linearity of better than 0.15% detector length are found. In addition, an energy linearity better than 0.3% and an energy resolution of 36 keV are measured. The latter will have to be improved, to make the PSD suitable for charged-particle spectroscopy applications. (orig.)

  18. Time-delay-and-integration charge coupled devices /CCDs/ applied to the Thematic Mapper. [onboard Landsat

    Science.gov (United States)

    Thompson, L. L.; Mccann, D. H.

    1978-01-01

    The visible focal plane of the Thematic Mapper, the next generation sensor system for application to earth resource survey, uses complex hybrid assembly techniques to interface silicon photodiodes to JFET preamplifiers. This complexity can be ameliorated by the use of a 20-channel time-delay-and-integration (TDI) CCD with nine stages of integration per channel. By going to a CCD array operating in a TDI mode, over 700 individual op amps can be replaced with only 48 op amps. Smooth spectral response and 70% quantum efficiency have been provided by using doped tin oxide gates over the imaging region.

  19. Sb2S3:C/CdS p-n junction by laser irradiation

    International Nuclear Information System (INIS)

    Arato, A.; Cardenas, E.; Shaji, S.; O'Brien, J.J.; Liu, J.; Castillo, G. Alan; Das Roy, T.K.; Krishnan, B.

    2009-01-01

    In this paper, we report laser irradiated carbon doping of Sb 2 S 3 thin films and formation of a p-n junction photovoltaic structure using these films. A very thin carbon layer was evaporated on to chemical bath deposited Sb 2 S 3 thin films of approximately 0.5 μm in thickness. Sb 2 S 3 thin films were prepared from a solution containing SbCl 3 and Na 2 S 2 O 3 at 27 deg. C for 5 h and the films obtained were highly resistive. These C/Sb 2 S 3 thin films were irradiated by an expanded laser beam of diameter approximately 0.5 cm (5 W power, 532 nm Verdi laser), for 2 min at ambient atmosphere. Morphology and composition of these films were analyzed. These films showed p-type conductivity due to carbon diffusion (Sb 2 S 3 :C) by the thermal energy generated by the absorption of laser radiation. In addition, these thin films were incorporated in a photovoltaic structure Ag/Sb 2 S 3 :C/CdS/ITO/Glass. For this, CdS thin film of 50 nm in thickness was deposited on a commercially available ITO coated glass substrate from a chemical bath containing CdCl 2 , sodium citrate, NH 4 OH and thiourea at 70 deg. C . On the CdS film, Sb 2 S 3 /C layers were deposited. This multilayer structure was subjected to the laser irradiation, C/Sb 2 S 3 side facing the beam. The p-n junction formed by p-Sb 2 S 3 :C and n-type CdS showed V oc = 500 mV and J sc = 0.5 mA/cm 2 under illumination by a tungsten halogen lamp. This work opens up a new method to produce solar cell structures by laser assisted material processing

  20. Detection of Transits of Extrasolar Giant Planets with Inexpensive Telescopes and CCDs

    Science.gov (United States)

    Castellano, T.; Laughlin, G.; Terry, R. S.; Kaufman, M.; Hubbert, S.; Schelbert, G. M.; Bohler, D.; Rhodes, R.

    2004-12-01

    A typical short-period giant planet occulting a parent star can produce a ~1% dimming of the star's light for an interval of several hours. The combination of photometric and Doppler radial velocity (RV) measurements of a transiting extrasolar planet can yield unambiguous measurements of the planet's mass, radius, density, and exact orbital parameters. In this article, we describe a low-cost observational and data-reduction pipeline which can be used to obtain 3 millimagnitude photometry with a small-aperture telescope and a consumer-grade CCD detector. This precision is sufficient to reliably detect the transit of a giant planet. We discuss noise sources, and evaluate strategies for achieving a low overall noise floor. We describe the performance of our pipeline in a successful observation of an HD 209458 "b" transit, and in a photometric survey of GJ 876 during an epoch in which we predicted that GJ 876 "c" (P ~30d) could potentially be observed to transit. We also briefly describe the status of the ongoing www.transitsearch.org project, which coordinates a photometric search for planetary transits among known planet-bearing stars.

  1. A fringe projector-based study of the Brighter-Fatter Effect in LSST CCDs

    Science.gov (United States)

    Gilbertson, W.; Nomerotski, A.; Takacs, P.

    2017-09-01

    To achieve the goals of the Large Synoptic Survey Telescope for Dark Energy science requires a detailed understanding of CCD sensor effects. One such sensor effect is the Point Spread Function (PSF) increasing with flux, alternatively called the `Brighter-Fatter Effect.' In this work a novel approach was tested to perform the PSF measurements in the context of the Brighter-Fatter Effect employing a Michelson interferometer to project a sinusoidal fringe pattern onto the CCD. The Brighter-Fatter effect predicts that the fringe pattern should become asymmetric in the intensity pattern as the brighter peaks corresponding to a larger flux are smeared by a larger PSF. By fitting the data with a model that allows for a changing PSF, the strength of the Brighter-Fatter effect can be evaluated.

  2. Chemical Research of Sir Prafulla Chandra Ray

    Indian Academy of Sciences (India)

    relatively unstable ions. The preparation of Hg2(NO)2 was an accidental discovery. He wanted to prepare water soluble mercurous nitrate as an inter- mediate for the synthesis of calomel, Hg2C12. Accordingly, di- lute aqueous nitric acid (1 :4) was reacted with excess mercury. To his surprise this resulted in the formation of ...

  3. Chemical Research of Sir Prafulla Chandra Ray

    Indian Academy of Sciences (India)

    Author Affiliations. Sreebrata Goswami1 Samaresh Bhattacharya2. Department of Inorganic Chemistry Indian Association for the Cultivation of Science Calcutta 700032, India. Department of Chemistry Inorganic Chemistry Section Jadavpur University Calcutta 700032, India.

  4. Harish-Chandra Research Institute, Allahabad

    Indian Academy of Sciences (India)

    The only experimental motivation for this question is the fact that there are certain anomalies in the data for neutrinos coming from the sun, as also from cosmic ray showers. At the theoretical level, a new symmetry among the elementary particles such as supersymmetry, or a new unification of the interactions could also lead ...

  5. 10th ACIS International Conference on Software Engineering Research, Management and Applications (SERA 2012)

    CERN Document Server

    Software Engineering Research, Management and Applications 2012

    2012-01-01

    The series Studies in Computational Intelligence (SCI) publishes new developments and advances in the various areas of computational intelligence-quickly and with a high quality.  The intent is to cover the theory, applications, and design methods of computational intelligence, as embedded in the fields of engineering, computer science, physics and life science, as well as the methodologies behind them.  The series contains monographs, lecture notes and edited volumes in computational intelligence spanning the areas of neural networks, connectionist systems, genetic algorithms, evolutionary computation, artificial intelligence, cellular automata, self-organizing systems, soft computing, fuzzy systems and hybrid intelligent systems. Critical to both contributors and readers are the short publication time and world-wide distribution-this permits a rapid and broad dissemination of research results.  The purpose of the 10th International Conference on Software Engineering Research, Management and Applications(...

  6. The Hippocratic treatise peri opsios (de Videndi Acie, On the organ of sight).

    Science.gov (United States)

    Craik, Elizabeth

    2005-01-01

    The nature and affiliations of the work are addressed. The closest affinities in medical subject matter (details of eye flux and cautery), linguistic expression (features of syntax, grammar and vocabulary) and stylistic tone (didactic and magisterial aspects) are seen to be with Places in Man. The inference that the work has an 'early' date and west Greek provenance, and that the author may have interacted with Alcmaeon or Empedocles, both known to have taken an interest in the eye, is examined. Evidence for an 'Egyptian' or 'Libyan' (North African) connection is adduced, and a case made for input from Cyrene.

  7. sanitizing effect of acetic aci andvegetables in k ffect of acetic acid

    African Journals Online (AJOL)

    userpc

    Kabir, A.*,. Department of Microbiolog. Corresponding autho. ABSTRACT. Fruits and vegetables promote good hea contaminants. To assess the sanitizing effe. 16 samples of sliced fruits and vegetables local government Kano. Samples were anal standard plate count (SPC). The samples concentration and exposure time ...

  8. Las ciudades como escenarios de la ensoñación

    Directory of Open Access Journals (Sweden)

    Carlos Carbonell

    2004-11-01

    Full Text Available El presente ensayo plantea una serie de consideraciones en torno a las relaciones entre la actividad turística y los imaginarios urbanos, a partir de las cuales es posible formular una lectura del turismo desde una perspectiva sociocultural. Los vínculos existentes entre itinerarios e imaginarios son analizados a la luz de la historia reciente, cuando se densificaron las redes globales de circulación, se mejoraron las tecnologías de transporte y comunicaciones y se popularizó la idea del viaje. Todos estos fenómenos confluyen en las ciudades contemporáneas, convirtiendo a las metrópolis en escenarios de encuentro entre turistas, habitantes y actores sociales que participan de diversas formas en las dinámicas generadas por el turismo y el aprovechamiento del tiempo libre, dando lugar a una reflexión sobre el papel del sector turístico en los procesos de construcción de ciudadanía.

  9. Andean Counterdrug Initiative (ACI) and Related Funding Programs: FY2007 Assistance

    National Research Council Canada - National Science Library

    Veillette, Connie

    2007-01-01

    ...), International Military Education and Training (IMET) funds, and other types of economic aid. Congress continued to express concern with the volume of drugs readily available in the United States and elsewhere in the world...

  10. 3rd ACIS International Conference on Applied Computing and Information Technology

    CERN Document Server

    2016-01-01

    This edited book presents scientific results of the 3nd International Conference on Applied Computing and Information Technology (ACIT 2015) which was held on July 12-16, 2015 in Okayama, Japan. The aim of this conference was to bring together researchers and scientists, businessmen and entrepreneurs, teachers, engineers, computer users, and students to discuss the numerous fields of computer science and to share their experiences and exchange new ideas and information in a meaningful way. Research results about all aspects (theory, applications and tools) of computer and information science, and to discuss the practical challenges encountered along the way and the solutions adopted to solve them.

  11. State/Spectral Transition of the Ultraluminous Supersoft X-ray Source in M101

    Science.gov (United States)

    Kong, A. K. H.; di Stefano, R.

    2004-01-01

    We analyzed recent archival Chandra observations of the spiral galaxy, M101, taken between 2004 Jan 19 and 2004 Jan 24. The ultraluminous supersoft X-ray source (CXOU J140332.3+542103) reported by Mukai et al. (2003) and Di Stefano and Kong (2003) was detected in 2 of 3 recent Chandra ACIS-S observations. In the first 56 ksec observation taken on 2004 Jan 19, 27 counts were detected in 0.1-7 keV, with 19 counts below 1.1 keV.

  12. The case of the galactic wind in the bright quasar 1H 0419-577

    Science.gov (United States)

    Di Gesu, L.; Costantini, E.; Piconcelli, E.

    2017-10-01

    We present the analysis of the first Chandra image ever obtained of the Seyfert 1 galaxy 1H 0419-577. This intriguing AGN is known to host a galactic-extended outflow, that is seen in the O III image, in the UV, and in the X-ray spectrum (Di Gesu et al. 2013). Using Chandra ACIS-S, we were also to observe extended X-ray emission. Ionized gas emitting at soft X-ray energies is detected with Chandra up to a distance of ˜10 kpc from the bright Seyfert nucleus. We will discuss possible scenarios for the physical nature of the extended emission, focusing on how it could be related to the galactic wind.

  13. pn-CCDs in a Low-Background Environment: Detector Background of the CAST X-ray Telescope

    CERN Document Server

    Kuster, M.; Rodriquez, A.; Kotthaus, R.; Brauninger, H.; Franz, J.; Friedrich, P.; Hartmann, R.; Kang, D.; Lutz, G.; Struder, L.

    2005-01-01

    The CAST experiment at CERN (European Organization of Nuclear Research) searches for axions from the sun. The axion is a pseudoscalar particle that was motivated by theory thirty years ago, with the intention to solve the strong CP problem. Together with the neutralino, the axion is one of the most promising dark matter candidates. The CAST experiment has been taking data during the last two years, setting an upper limit on the coupling of axions to photons more restrictive than from any other solar axion search in the mass range below 0.1 eV. In 2005 CAST will enter a new experimental phase extending the sensitivity of the experiment to higher axion masses. The CAST experiment strongly profits from technology developed for high energy physics and for X-ray astronomy: A superconducting prototype LHC magnet is used to convert potential axions to detectable X-rays in the 1-10 keV range via the inverse Primakoff effect. The most sensitive detector system of CAST is a spin-off from space technology, a Wolter I ty...

  14. Performance of the X-ray CCDs aboard the ASCA satellite after 5-year operation in space

    CERN Document Server

    Yamashita, A; Ezuka, H; Kawasaki, M; Takahashi, K

    1999-01-01

    The performance of the charge coupled devices on-board the ASCA satellite has been traced for five years after the launch. We found the gradual increase of the dark current and the decrease of the charge transfer efficiency. These changes may be explained by charge traps due to the radiation damage. The nature of the radiation damage is investigated in detail using various methods.

  15. Vínculos sobre um modelo de quartessência de Chaplygin usando observações do satélite chandra da fração de massa de gás em aglomerados de galáxias

    Science.gov (United States)

    de Souza, R. S.

    2003-08-01

    Observações de Supernovas do tipo Ia mostram que a expansão do Universo está acelerando. Segundo as equações de Einstein uma componente com pressão negativa (energia escura) é necessária para explicar a aceleração cósmica. Além da energia escura é usualmente admitido que no Universo há também uma matéria exótica com pressão zero, que é chamada de matéria escura. Essa componente possui um papel fundamental na formação de estruturas no Universo. Recentemente tem se explorado a possibilidade de que matéria e energia escura poderiam ser unificadas através de uma única componente, que tem sido denominada de quartessência. Um exemplo de fluido com essas características é o Gás de Chaplygin Generalizado, que possui uma equação de estado da forma p = -A/ra. Inicialmente consideramos o caso especial a = 1 (gás de Chaplygin) e vinculamos parâmetros do modelo utilizando observações em raios-X do satélite Chandra da fração de massa de gás em aglomerados de galáxias. Uma comparação dos vínculos obtidos com esse teste com outros testes, tais como supernovas e idade do Universo, mostra que esse teste é bastante restritivo. Exibiremos ainda resultados para o caso em que a curvatura é nula e o parâmetro a está compreendido no intervalo -1 < a 1.

  16. El vino en el hinterland del Portus de Saguntum (ss. I a.C.-I d.C.

    Directory of Open Access Journals (Sweden)

    F. Cisneros Fraile

    2002-01-01

    Full Text Available Durante la época augustea, el vino fue una de las mercancías más frecuentemente comercializadas dentro del ámbito económico del Imperio Romano.Los ss. 1 a.C. y 1 d. C. presenciaron una verdadera internacionalización del comercio vinícola. Por ello, los puertos fueron un elemento esencial en relación con un municipiumn y con una zona subsidiaria donde se ubicaban las villae productoras de vino, generalmente en situación litoral, aunque algunas de ellas se establecieron más al interior junto a cursos fluviales utilizados como vías de comunicación. En la actualidad, alrededor de cada puerto existe una amplia zona que depende económicamente de él. De la misma manera, el puerto romano de Saguntum dispuso de un amplio hinterland en el que se desarrolló, desde los momentos iniciales del s. 1 a.C., una importante zona vinícola siguiendo el modelo de producción romano. En este artículo reflejamos e interpretamos algunos de los restos arqueológicos relacionados con el vino: villae, alfares, embarcaderos, ánforas (algunas de ellas con marcas impresas.

  17. Transfer of the Rf-1 region from FHH onto the ACI background increases susceptibility to renal impairment

    NARCIS (Netherlands)

    Provoost, AP; Shiozawa, M; Van Dokkum, RPE; Jacob, HJ

    2002-01-01

    The genetically hypertensive fawn-hooded (FHH/Eur) rat is characterized by the early presence of systolic and glomerular hypertension, progressive proteinuria (UPV), and albuminuria (UAV), and focal glomerulosclerosis, resulting in premature death from renal failure. Previous studies showed that at

  18. Le groupe de coordination existe-t-il? - Un aspect de l'ACI revisité

    DEFF Research Database (Denmark)

    Kjærsgaard, Poul Søren

    2008-01-01

    Artiklen sætter, at der findes et koordinationssyntagme, skønt syntagmer ellers er en funktion af ordklasser. De praktiske og teoretiske implikationer af denne tese diskuteres.......Artiklen sætter, at der findes et koordinationssyntagme, skønt syntagmer ellers er en funktion af ordklasser. De praktiske og teoretiske implikationer af denne tese diskuteres....

  19. Co-Optima Project E2.2.2: Accelerate Development of ACI/LTC Fuel Effects on RCCI Combustion.

    Energy Technology Data Exchange (ETDEWEB)

    Musculus, Mark P. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2017-11-01

    Many advanced combustion approaches have demonstrated potential for achieving diesel-like thermal efficiency but with much lower pollutant emissions of particulate matter (PM) and nitrogen oxides (NOx). RCCI is one advanced combustion concept, which makes use of in-cylinder blending of two fuels with differing reactivity for improved control of the combustion phasing and rate (Reitz et al., 2015). Previous research and development at ORNL has demonstrated successful implementation of RCCI on a light-duty multi-cylinder engine over a wide range of operating conditions (Curran et al., 2015). Several challenges were encountered when extending the research to practical applications, including limits to the operating range, both for high and low loads. Co-optimizing the engine and fuel aspects of the RCCI approach might allow these operating limits to be overcome. The in-cylinder mechanisms by which fuel properties interact with engine operating condition variables is not well understood, however, in part because RCCI is a new combustion concept that is still being developed, and limited data have been acquired to date, especially using in-cylinder optical/imaging diagnostics. The objective of this work is to use in-cylinder diagnostics in a heavy-duty single-cylinder optical engine at SNL to understand the interplay between fuel properties and engine hardware and operating conditions for RCCI in general, and in particular for the light-duty multi-cylinder all-metal RCCI engine experiments at ORNL.

  20. Advanced Cyber Industrial Control System Tactics, Techniques, and Procedures (ACI TTP) for Department of Defense (DOD) Industrial Control Systems (ICS)

    Science.gov (United States)

    2016-08-10

    analysis. Typical Equipment: IEDs; Protective Relay Controllers, Tap Changer Controllers, Circuit Breaker Controllers, Capacitor Bank Switches, Switch...Circuit Breaker Controllers, Capacitor Bank Switches, Switch Re-closer Controllers, Voltage Regulators, Etc. 12. VERIFY that each device in the isolated

  1. DETECTION OF VERY LOW-FREQUENCY, QUASI-PERIODIC OSCILLATIONS IN THE 2015 OUTBURST OF V404 CYGNI

    Energy Technology Data Exchange (ETDEWEB)

    Huppenkothen, D. [Center for Data Science, New York University, 726 Broadway, 7th Floor, New York, NY 10003 (United States); Younes, G.; Kouveliotou, C. [Department of Physics, The George Washington University, Washington, DC 20052 (United States); Ingram, A.; Van der Klis, M. [Anton Pannekoek Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Göğüş, E. [Sabancı University, Orhanlı-Tuzla, İstanbul 34956 (Turkey); Bachetti, M. [INAF/Osservatorio Astronomico di Cagliari, via della Scienza 5, I-09047 Selargius (Italy); Sánchez-Fernández, C.; Kuulkers, E. [European Space Astronomy Centre (ESA/ESAC), Science Operations Department, E-28691 Villanueva de la Cañada, Madrid (Spain); Chenevez, J. [DTU Space—National Space Institute, Technical University of Denmark, Elektrovej 327-328, DK-2800 Lyngby (Denmark); Motta, S. [University of Oxford, Department of Physics, Astrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Raanana 43537 (Israel); Gehrels, N. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Tomsick, J. A. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Walton, D. J., E-mail: daniela.huppenkothen@nyu.edu [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)

    2017-01-01

    In 2015 June, the black hole X-ray binary (BHXRB) V404 Cygni went into outburst for the first time since 1989. Here, we present a comprehensive search for quasi-periodic oscillations (QPOs) of V404 Cygni during its recent outburst, utilizing data from six instruments on board five different X-ray missions: Swift /XRT, Fermi /GBM, Chandra /ACIS, INTEGRAL ’s IBIS/ISGRI and JEM-X, and NuSTAR . We report the detection of a QPO at 18 mHz simultaneously with both Fermi /GBM and Swift /XRT, another example of a rare but slowly growing new class of mHz-QPOs in BHXRBs linked to sources with a high orbital inclination. Additionally, we find a duo of QPOs in a Chandra /ACIS observation at 73 mHz and 1.03 Hz, as well as a QPO at 136 mHz in a single Swift /XRT observation that can be interpreted as standard Type-C QPOs. Aside from the detected QPOs, there is significant structure in the broadband power, with a strong feature observable in the Chandra observations between 0.1 and 1 Hz. We discuss our results in the context of current models for QPO formation.

  2. Chandra Cluster Cosmology Project III: Cosmological Parameter Constraints

    DEFF Research Database (Denmark)

    Vikhlinin, A.; Kravtsov, A. V.; Burenin, R. A.

    2009-01-01

    constraints when combined with other methods. Fitting our cluster data jointly with the latest supernovae, Wilkinson Microwave Anisotropy Probe, and baryonic acoustic oscillation measurements, we obtain w 0 = –0.991 ± 0.045 (stat) ±0.039 (sys), a factor of 1.5 reduction in statistical uncertainties...

  3. Chandra HETGS Followup of a Gravitational Wave Detection

    Science.gov (United States)

    Canizares, Claude

    2017-09-01

    Mergers of compact objects in tight binaries are considered to be highly promising astrophysical sources of detectable gravitational wave (GW) emission. The first detection was obtained in 2015 for a black hole binary. Finding electromagnetic counterparts to GW events will be essential for astrophysical interpretation so that more instruments may be brought to bear on elucidating the nature of the merger and especially for following the aftereffects. Initial error regions may be very large ( 100 sq. deg), so we will use a bright Swift source identification before triggering this TOO using the HETGS.

  4. The Chandra COSMOS-Legacy Survey: The z>3 Sample

    Science.gov (United States)

    Marchesi, S.; Civano, F.; Salvato, M.; Shankar, F.; Comastri, A.; Elvis, M.; Lanzuisi, G.; Trakhtenbrot, B.; Vignali, C.; Zamorani, G.; Allevato, V.; Brusa, M.; Fiore, F.; Gilli, R.; Griffiths, R.; Hasinger, G.; Miyaji, T.; Schawinski, K.; Treister, E.; Urry, C. M.

    2016-08-01

    We present the largest high-redshift (3 0 at z > 3. We compute the number counts in the observed 0.5-2 keV band, finding a decline in the number of sources at z > 3 and constraining phenomenological models of the X-ray background. We compute the AGN space density at z > 3 in two different luminosity bins. At higher luminosities (logL(2-10 keV) > 44.1 erg s-1), the space density declines exponentially, dropping by a factor of ˜20 from z ˜ 3 to z ˜ 6. The observed decline is ˜80% steeper at lower luminosities (43.55 erg s-1 evolution dividing our sample into optically classified Type 1 and Type 2 AGNs. At logL(2-10 keV) > 44.1 erg s-1, unobscured and obscured objects may have different evolution with redshift, with the obscured component being three times higher at z ˜ 5. Finally, we compare our space density with predictions of quasar activation merger models, whose calibration is based on optically luminous AGNs. These models significantly overpredict the number of expected AGNs at logL (2-10 keV) > 44.1 erg s-1 with respect to our data.

  5. 2017-2018 Travel Expense Reports for Chandra Madramootoo, Vice ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Chantal Taylor

    07-11. Destination(s):. Kenya, Uganda and Tanzania. Airfare: $4,788.97. Other. Transportation: $147.43. Accommodation: $2,058.50. Meals and. Incidentals: $701.92. Other: $399.15. Total: $8,095.97. Comments: From residence in Montreal, ...

  6. Optical Followup of Extragalactic Radio Sources CH Ishwara-Chandra

    Indian Academy of Sciences (India)

    Abstract. Distance measurement is a must to characterize any source in the sky. In the radio band, it is rarely possible to get distance or redshift measurements. The optical band is the most used band to get distance esti- mate of sources, even for those originally discovered in other bands of the electromagnetic spectrum.

  7. 2016-2017 Expense report for Chandra Madramootoo | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2017-03-20

    $10,750.19. Board meetings. March 20, 2017 to March 22, 2017. CA$821.31. Board meetings. November 20, 2016 to November 23, 2016. CA$907.94. Orientation on research impact for new Governors. August 14, 2016 to August 23, 2016.

  8. Rejoinder Authors' reply to the comments made by Suresh Chandra ...

    Indian Academy of Sciences (India)

    Equation (1a) is the one we have used to have the approximate values. Relations (1) are applicable when the quadratic equation, ω0v-ω0x0v2 represents all the vibrational levels correctly. That means, ∆G is a linear function of v. Usually, this is not the case with most of the molecules as ∆G vs v curve deviates significantly at ...

  9. 2016-2017 Travel Expense Reports for Chandra Madramootoo, Vice ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Beata Bialic

    14 to 2016-08-23. Destination(s):. Peru/Colombia. Airfare: $6,070.40. Other. Transportation: $142.60. Accommodation: $1,512.99. Meals and. Incidentals: $411.51. Other: $0.00. Total: $8,137.50. Comments: 2016-2017 Travel Expense Reports ...

  10. Mandibular Fractures at Veer Chandra Singh Garhwali Government ...

    African Journals Online (AJOL)

    44% of mandibular fractures were associated with alcohol abuse.[26] The present study shows a very low incidence of mandibular fractures due to assault or violence i.e., 6.6%. It has been found in various studies that use of alcohol in men is a key factor in causing facial fractures. Combination of drinking and driving has ...

  11. Two new supersoft X-ray sources in M31 identified as classical novae

    Science.gov (United States)

    Nelson, T.; Liu, J. F.; di Stefano, R.; Orio, M.; Patel, B.; Primini, F.; Shafter, A. W.

    2008-08-01

    We report the identification of two previously unpublished supersoft X-ray sources (SSS) in M31 as classical novae. The X-ray sources were discovered during a comprehensive search of all archival Chandra/ACIS images of M31 for so-called "Very Soft Sources" (VSS, see Di Stefano & Kong 2003 ApJ, 592, 884). The identification with classical novae was made as part of a larger campaign aimed at optical identification and classification of SSS in M31, and made use of the list of novae in M31 compiled by Pietsch et al.

  12. Interstellar Abundances Toward X Per, Revisited

    Science.gov (United States)

    Valencic, Lynne A.; Smith, Randall K.

    2014-01-01

    The nearby X-ray binary X Per (HD 24534) provides a useful beacon with which to measure elemental abundances in the local ISM. We examine absorption features of 0, Mg, and Si along this line of sight using spectra from the Chandra Observatory's LETG/ ACIS-S and XMM-Newton's RGS instruments. In general, we find that the abundances and their ratios are similar to those of young F and G stars and the most recent solar values. We compare our results with abundances required by dust grain models.

  13. Mapping the Extended Hard (>3 keV) Continuum and Fluorescent 6.4 keV Iron Emission of the CT AGN NGC7212

    Science.gov (United States)

    Fabbiano, Giuseppina

    2017-09-01

    Recent Chandra studies of Compton thick (CT) AGNs have led to the discovery of 1-2 kpc-scale extended hard (>3 keV) continuum and Fe Kα components, showing that these emissions are not confined to the immediate vicinity of the AGN (the CT torus ). This is an important discovery as it changes our perception of CT AGNs and their interaction with their host galaxies. It may provide a unique probe of the host ISM, and/or the interaction of a radio jet or wind, including ultra-fast outflows (UFOs), with a dense ISM. Suitable CT AGNs close enough to resolve this region are rare, but a Chandra archival investigation has identified NGC7212 as an optimal target. We propose 130ks with ACIS-S to provide the deep data needed for this investigation.

  14. Cosmic Payback: Giant Galaxy Reacts to Being Dumped On

    Science.gov (United States)

    1999-11-01

    powerful payback for eons of being dumped on by a cosmic bully. The Chandra image was taken with the Advanced CCD Imaging Spectrometer (ACIS) on August 30, 1999 in an observation that lasted about six hours. ACIS was built by Penn State Univ. and MIT. The image has been colorized to highlight the intense X-radiation from the X-ray knots in 3C295. To follow Chandra's progress, visit the Chandra site at: http://chandra.harvard.edu AND http://chandra.nasa.gov NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. High resolution digital versions of the X-ray image (JPG, 300 dpi TIFF) and other information associated with this release are available on the Internet at: http://chandra.harvard.edu/photo/0166/ or via links in: http://chandra.harvard.edu

  15. Scientists Discover Supernova May Control Activity in the Center of Our Galaxy

    Science.gov (United States)

    2001-02-01

    10 January 2001 -- Scientists using NASA's Chandra X-ray Observatory have discovered that an apparent supernova remnant in the center of our galaxy might help regulate a nearby supermassive black hole and that such relationships between supernova remnants and black holes might be common throughout the universe. The scientists studied Sagittarius A East, previously known by its ring-shaped radio emission, located nearly 26,000 light years from Earth in the constellation Sagittarius. Sgr A East appears to surround the black hole Sagittarius A* (denoted with an asterisk because it is a point source that emits radio waves) with its center offset by about six light years from that of the black hole. Using Chandra, scientists were able to separate Sgr A East from other complex structures for the first time in X-ray wavelengths. The properties they discovered support the long-standing hypothesis that Sgr A East is a single supernova remnant that exploded about 10,000 years ago. "With Chandra, we found hot gas concentrated within the larger radio shell of Sgr A East," said Yoshitomo Maeda, an astronomy and astrophysics research associate at Penn State who presented the research team's results at the 197th national meeting of the American Astronomical Society in San Diego, California, on 10 January 2001. "The gas is highly enriched by heavy elements, with four times more calcium and iron than the Sun, and that confirms earlier suspicions that Sgr A East is most likely a remnant of a supernova explosion. While dozens of supernova remnants are known in our galaxy, the proximity of Sgr A East to the black hole in the center of our galaxy makes it important." After a supernova explosion, scientists believe two shock waves are formed, with one moving inward and one outward. The inward shock wave heated up the ejecta that was detected with X-rays by the Advanced CCD Imaging Spectrometer (ACIS) aboard Chandra. The temperature of gas in that shock wave was measured at 20 million

  16. VizieR Online Data Catalog: X-ray observations of HCG galaxies (Tzanavaris+, 2016)

    Science.gov (United States)

    Tzanavaris, P.; Hornschemeier, A. E.; Gallagher, S. C.; Lenkic, L.; Desjardins, T. D.; Walker, L. M.; Johnson, K. E.; Mulchaey, J. S.

    2016-04-01

    In this paper we study a sample of 15 compact groups (CGs) observed with Chandra/ACIS, Swift/UVOT and Spitzer/IRAC-MIPS for which archival data exist, allowing us to obtain SFRs, stellar masses, sSFRs and X-ray fluxes and luminosities. Table 1 shows the group sample, including redshifts, luminosity distances and group evolutionary types. Allowing for the fact that some galaxies do not fall in the field of view of all three instruments, the total number of CG galaxies analyzed is 47. Details on the Swift and Spitzer observations and data for systems in this sample can be found in Tzanavaris et al. (2010ApJ...716..556T) and (L. Lenkic et al. 2015, in preparation). For Chandra/ACIS observations we refer the reader to Tzanavaris et al. (2014, J/ApJS/212/9) and Desjardins et al. (2013ApJ...763..121D; 2014ApJ...790..132D). (2 data files).

  17. SYSTEMATIC UNCERTAINTIES IN THE SPECTROSCOPIC MEASUREMENTS OF NEUTRON STAR MASSES AND RADII FROM THERMONUCLEAR X-RAY BURSTS. III. ABSOLUTE FLUX CALIBRATION

    Energy Technology Data Exchange (ETDEWEB)

    Güver, Tolga [Istanbul University, Science Faculty, Department of Astronomy and Space Sciences, Beyazıt, 34119, Istanbul (Turkey); Özel, Feryal; Psaltis, Dimitrios [Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Marshall, Herman [Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Guainazzi, Matteo [European Space Astronomy Centre of ESA, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Díaz-Trigo, Maria [ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany)

    2016-09-20

    Many techniques for measuring neutron star radii rely on absolute flux measurements in the X-rays. As a result, one of the fundamental uncertainties in these spectroscopic measurements arises from the absolute flux calibrations of the detectors being used. Using the stable X-ray burster, GS 1826–238, and its simultaneous observations by Chandra HETG/ACIS-S and RXTE /PCA as well as by XMM-Newton EPIC-pn and RXTE /PCA, we quantify the degree of uncertainty in the flux calibration by assessing the differences between the measured fluxes during bursts. We find that the RXTE /PCA and the Chandra gratings measurements agree with each other within their formal uncertainties, increasing our confidence in these flux measurements. In contrast, XMM-Newton EPIC-pn measures 14.0 ± 0.3% less flux than the RXTE /PCA. This is consistent with the previously reported discrepancy with the flux measurements of EPIC-pn, compared with EPIC MOS1, MOS2, and ACIS-S detectors. We also show that any intrinsic time-dependent systematic uncertainty that may exist in the calibration of the satellites has already been implicity taken into account in the neutron star radius measurements.

  18. The simulated spectrum of the OGRE X-ray EM-CCD camera system

    Science.gov (United States)

    Lewis, M.; Soman, M.; Holland, A.; Lumb, D.; Tutt, J.; McEntaffer, R.; Schultz, T.; Holland, K.

    2017-12-01

    The X-ray astronomical telescopes in use today, such as Chandra and XMM-Newton, use X-ray grating spectrometers to probe the high energy physics of the Universe. These instruments typically use reflective optics for focussing onto gratings that disperse incident X-rays across a detector, often a Charge-Coupled Device (CCD). The X-ray energy is determined from the position that it was detected on the CCD. Improved technology for the next generation of X-ray grating spectrometers has been developed and will be tested on a sounding rocket experiment known as the Off-plane Grating Rocket Experiment (OGRE). OGRE aims to capture the highest resolution soft X-ray spectrum of Capella, a well-known astronomical X-ray source, during an observation period lasting between 3 and 6 minutes whilst proving the performance and suitability of three key components. These three components consist of a telescope made from silicon mirrors, gold coated silicon X-ray diffraction gratings and a camera that comprises of four Electron-Multiplying (EM)-CCDs that will be arranged to observe the soft X-rays dispersed by the gratings. EM-CCDs have an architecture similar to standard CCDs, with the addition of an EM gain register where the electron signal is amplified so that the effective signal-to-noise ratio of the imager is improved. The devices also have incredibly favourable Quantum Efficiency values for detecting soft X-ray photons. On OGRE, this improved detector performance allows for easier identification of low energy X-rays and fast readouts due to the amplified signal charge making readout noise almost negligible. A simulation that applies the OGRE instrument performance to the Capella soft X-ray spectrum has been developed that allows the distribution of X-rays onto the EM-CCDs to be predicted. A proposed optical model is also discussed which would enable the missions minimum success criteria's photon count requirement to have a high chance of being met with the shortest possible

  19. Development and evaluation of a new radiographic and fluoroscopic imager based on electron-multiplying CCDs: The solid state x-ray image intensifier

    Science.gov (United States)

    Kuhls-Gilcrist, Andrew Thomas

    A new dual detector system was developed which utilizes a low resolution, large field-of-view x-ray image intensifier (II) and a high resolution, region-of-interest microangiographic (MA) detector on the same c-arm gantry. With this new MA-II system, the larger field-of-view (FOV) II can be operated when the demands of the task are not as high, and a larger imaging area is desired. However, when a higher-resolution image with greater image quality is desired at a targeted region-of-interest (ROI), the MA can be deployed to take on these greater demands. To quantitatively and qualitatively assess the imaging performance of each detector under realistic conditions, angiographic images of simulated vessels and rabbit neurovasculature were acquired with both detectors under nearly identical conditions. With the MA detector deployed, vessels as small as 95 mum were visible, whereas the II could not detect vessels smaller than 235 mum. The ROI MA mode was also shown to provide sharper images with higher contrast-to-noise ratios and was four times as likely to successfully detect overlapping vessels as compared to the II. More accurate three-dimensional center lines of vasculature using multi-view reconstruction techniques were also obtained with the MA. The solid state x-ray image intensifier (SSXII) was developed to provide similar high-resolution imaging capabilities as the MA and a built in adjustable gain to provide high-sensitivity imaging capabilities for operation at all exposures used in medical x-ray imaging procedures. The imaging components used in construction of the prototype SSXII were selected based on a theoretical performance evaluation, using a Fourier-based linear-systems model analysis. The performance of the prototype SSXII was then extensively evaluated. Images of various objects and image comparisons with current state-of-the-art detectors qualitatively demonstrated that the SSXII is capable of providing substantial improvements. A quantitative assessment of spatial resolution, noise performance, and overall performance was then determined using MTF, INEE, and DQE measurements. In addition to the overall performance of the SSXII, the performances of individual components were determined using measurements of their resolution and transmission efficiency. The unique ability of the SSXII to operate in both tradition energy integrating (EI) mode and single photon counting (SPC) mode was also demonstrated. To better assess detector performance, a new method for determination of the two-dimensional presampled MTF, the "noise-response method", was developed and evaluated. Compared to current measurement methods, the noise-response method simplifies the MTF determination by eliminating the need for manufacture and alignment of precisely machined test objects, thereby eliminating inaccuracies that result from the use of such objects and subsequent analysis of the resulting images. The accuracy of this method was demonstrated using both simulated and experimental data sets. For the simulated image set which used a simple detector model for which the "true" MTF was known exactly, excellent agreement was obtained with the MTF determined using the noise-response method, with a maximum deviation of 1.1%. Comparison measurements were also made on this simulated data set with the established edge-response method and these showed deviations greater than 35% from the "true" MTF. Experimental measurements on a range of detector technologies (including an XII, FPD and SSXII) demonstrated agreement between the noise-response and edge-response methods within experimental uncertainty, with discrepancies likely resulting from errors inherent in the edge-response MTF procedure. The two-dimensional MTF for the FPD was non-isotropic, with an increase observed on the diagonals, whereas the SSXII MTF was shown to be largely symmetric. Initial results indicate that the new noise-response method is a promising candidate to replace existing standard methods. To further assess detector performance, the instrumentation noise equivalent exposure (INEE) metric has been developed to address the need for a direct, quantitative measure of the quantum-noise-limited exposure range of x-ray detectors by providing the threshold exposure at which the detector instrumentation-noise exceeds the quantum-noise. Frequency dependence and all instrumentation noise sources were investigated to provide a greater understanding of this promising new metric and to ensure quantum noise limited operation at every spatial frequency of interest. Measurements were done on various x-ray detectors to demonstrate the usefulness of these new developments. In addition to providing a practical quantification of instrumentation noise, the INEE was also shown to provide insight into overall detector performance in terms of the behavior of the DQE as a function of exposure. (Abstract shortened by UMI.)

  20. Effect of extra-fine slag replacement on carbonation and frost salt scaling resistance of mortars[ACI SP-234-8

    Energy Technology Data Exchange (ETDEWEB)

    Copuroglu, O.; Fraaij, A.; Schlangen, E. [Delft Univ. of Technology, Delft (Netherlands). Dept. of Civil Engineering; Bijen, J. [INTRON (Netherlands)

    2006-07-01

    This study examined the effects of extra-fine slag (EFS) on the carbonation and frost salt scaling resistance of mortars at different replacement levels for 2 types of cements. In the first part of the examination, EFS replaced a certain amount of European CEM 3/B cement composed of 67 per cent slag with ordinary fineness. The second part examined the effect of EFS on microstructure and frost salt scaling resistance of mortars at different replacement levels in European normal portland cement CEM 1 32,5R. The average Blaine fineness of EFS was 500 m{sup 2}/kg. The water to cement ratio was maintained at 0.45. The carbonation resistance and pore structure of the cement mortars was examined. Carbonation resistance was measured using the phenolphthalein method after accelerated carbonation tests in a 3 per cent carbon dioxide chamber. Mercury intrusion porosimetry was used to study the pore structures. The chemical and physical properties of this cement were presented along with the obtained cement blends. The first part of the study showed that increasing the average fineness and total amount of slag results in a higher degrees of water uptake compared to the control sample. Therefore, it was claimed that the critical amount of normal portland cement clinker is important in terms of carbonation and frost salt scaling durability. It was concluded that an increasing EFS content lowers the scaling resistance. The effect is most evident when the replacement percentage is increased from 50 to 75 per cent. It was suggested that future studies should focus on the content of normal portland cement clinker, the hydration rate of clinker and slag, as well as the related activation of the slag. 10 refs., 5 tabs., 12 figs.

  1. Comparison of Cortical Epileptic Afterdischarges in Immature Genetic Absence Epilepsy WAG/Rij Rats with Those in Two Other Strains (ACI and Wistar)

    Czech Academy of Sciences Publication Activity Database

    Mareš, Pavel; Tolmacheva, E. A.

    2007-01-01

    Roč. 48, Suppl.5 (2007), s. 164-167 ISSN 0013-9580 R&D Projects: GA ČR(CZ) GA305/05/2581 Institutional research plan: CEZ:AV0Z50110509 Keywords : epileptic afterdischarges * cerebral cortex * electrical stimulation Subject RIV: ED - Physiology Impact factor: 3.569, year: 2007

  2. A multi-component modifier for shrinkage-compensated or self-stressed high-strength concrete[ACI SP-239

    Energy Technology Data Exchange (ETDEWEB)

    Kaprielov, S.; Sheynfeld, A.; Kardumian, H.; Dondukov, V. [Research Inst. for Concrete, Moscow (Russian Federation). Lab. for Chemical Admixtures and Modified Concrete

    2006-07-01

    New modifiers for cements used in Russia have initiated the development of a new modifier in which silica fume (SF) and fly ash (FA) are partially or completely replaced by metakaolin (MK) and calcium sulfate. The mixture acts as a sulfoaluminate type expansive compound (EC) due to the generation of ettringite. The aim of this study was to examine the correlation between the amount of EC in a modifier and the parameters of cement paste structure and concrete properties. The phase composition and porosity of cement paste was investigated, as well as the concrete strength, the modulus of elasticity, expansion-shrinkage, and creep. The influence of different dosages of the modifiers with maximum EC content on cement paste characteristics was also examined. Portland cement, quartz sands, and granite coarse aggregates were used. Results of the study showed that ettringite is present mostly in the form of gel-like and microcrystalline new growths, which contribute to the stability of cement systems. The porosity of cement paste was characterized by a decrease in macropore volume, and an increase in gel pore and micropore volume. Variations in the amount of EC in the mineral part of the modifier provided control of expansion-shrinkage deformations. An increased modulus of elasticity and decreased creep factor was observed. It was concluded that using complex organic mineral modifiers containing EC on a base of metakaolin can lead to fine-grained concrete with deformation parameters comparable with heavy-weight granite coarse aggregate-based concrete. 8 refs., 4 tabs., 6 figs.

  3. Pre-wetted lightweight coarse aggregate reduces long-term deformations of high-performance lightweight concrete[ACI SP-234-41

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, M. [Chile Catholic Pontifica Univ. (Chile). School of Civil Engineering]|[Georgia Inst. of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering; Kurtis, K.E.; Kahn, L.F. [Georgia Inst. of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering

    2006-07-01

    High performance lightweight concrete (HPLC) refers to concretes that have the characteristics of both high performance concrete and structural lightweight concrete. HPLC has advantages from the synergy between its two predecessors. The advantages include improvement in elastic compatibility between aggregate and cementitious matrix which leads to reduced microcracking in the interface zone; improvement in cement hydration due to internal curing; and reduction in autogenous shrinkage of the cement matrix. Although extensive studies on HPLC durability, compressive strength and shrinkage have been carried out, the creep of HPLC and the influence of internal curing on creep of HPLC remain unknown. For that reason, this study focused on creep and shrinkage results and analysis. The use of HPLC in prestressed bridge girders can extend the length of the bridge girders by 15 to 20 per cent. Long-term creep and shrinkage deformations are of particular interest in understanding the implications of using lightweight aggregate on prestressing losses. In this study, creep was measured on 45 specimens stored at 50 per cent relative humidity and 23 degrees C for a period of 120 days. Fifteen cylindrical specimens were cast from each of 3 mixtures under study. In addition, 30 specimens were used as companion shrinkage specimens. The study compared creep and shrinkage behaviour of various specimens, as well as creep and shrinkage behaviour with loading and drying starting at the age of 24 hours and at 28 days. The total time dependent deformations with loading and drying starting at the age of 24 hours and at 28 days were also examined. Preliminary results on the reported concrete mixtures indicate lower long-term deformation for HPLC compared to high performance concrete. The results confirm observations in literature that the water initially stored in the aggregate is released over time and reduces the long-term duration of the HPLC. It was noted that the creep and shrinkage of high performance concrete mixtures may vary widely depending on the aggregates, supplementary cementitious materials, and admixtures. It was suggested that future studies should focus on measuring changes in internal relative humidity in sealed and unsealed specimens produced with pre-wetted and air-dried lightweight aggregate and normal weight aggregate under loading and drying conditions. 50 refs., 4 tabs., 5 figs.

  4. X-Ray Spectral Properties of Seven Heavily Obscured Seyfert 2 Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, S.; Ajello, M. [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Comastri, A. [INAF—Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Cusumano, G.; Parola, V. La; Segreto, A., E-mail: smarche@clemson.edu [INAF—Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy)

    2017-02-10

    We present the combined Chandra and Swift -BAT spectral analysis of seven Seyfert 2 galaxies selected from the Swift -BAT 100 month catalog. We selected nearby ( z ≤ 0.03) sources lacking a ROSAT counterpart that never previously been observed with Chandra in the 0.3–10 keV energy range, and targeted these objects with 10 ks Chandra ACIS-S observations. The X-ray spectral fitting over the 0.3–150 keV energy range allows us to determine that all the objects are significantly obscured, with N{sub H} ≥ 10{sup 23} cm{sup −2} at a >99% confidence level. Moreover, one to three sources are candidate Compton-thick Active Galactic Nuclei (CT-AGNs; i.e., N{sub H}≥10{sup 24} cm{sup −2}). We also test the recent spectral curvature method developed by Koss et al. to find candidate CT-AGNs, finding a good agreement between our results and their predictions. Because the selection criteria we adopted were effective in detecting highly obscured AGNs, further observations of these and other Seyfert 2 galaxies selected from the Swift -BAT 100 month catalog will allow us to create a statistically significant sample of highly obscured AGNs, therefore providing a better understanding of the physics of the obscuration processes.

  5. X-ray Pulsars Across the Parameter Space of Luminosity, Accretion Mode, and Spin

    Science.gov (United States)

    Laycock, Silas

    We propose to expand the scope of our successful project providing a multi-satellite library of X-ray Pulsar observations to the community. The library provides high-level products, activity monitoring, pulse-profiles, phased event files, spectra, and a unique pulse-profile modeling interface. The library's scientific footprint will expand in 4 key directions: (1) Update, by processing all new XMM-Newton and Chandra observations (2015-2017) of X-ray Binary Pulsars in the Magellanic Clouds. (2) Expand, by including all archival Suzaku, Swift and NuStar observations, and including Galactic pulsars. (3) Improve, by offering innovative data products that provide deeper insight. (4) Advance, by implementing a new generation of physically motivated emission and pulse-profile models. The library currently includes some 2000 individual RXTE-PCA, 200 Chandra ACIS-I, and 120 XMM-PN observations of the SMC spanning 15 years, creating an unrivaled record of pulsar temporal behavior. In Phase-2, additional observations of SMC pulsars will be added: 221 Chandra (ACIS-S and ACIS-I), 22 XMM-PN, 142 XMM-MOS, 92 Suzaku, 25 NuSTAR, and >10,000 Swift; leveraging our pipeline and analysis techniques already developed. With the addition of 7 Galactic pulsars each having many hundred multisatellite observations, these datasets cover the entire range of variability timescales and accretion regimes. We will model the pulse-profiles using state of the art techniques to parameterize their morphology and obtain the distribution of offsets between magnetic and spin axes, and create samples of profiles under specific accretion modes (whether pencil-beam or fan-beam dominated). These products are needed for the next generation of advances in neutron star theory and modeling. The long-duration of the dataset and “whole-galaxy" nature of the SMC sample make possible a new statistical approach to uncover the duty-cycle distribution and hence population demographics of transient High Mass X

  6. Radioimmunodetection using anti-TPA iodine-125 in SD rats suffering from Walker's carcinosarcoma and ACI rats having carcinomas of the bladder. Radioimmunodetection mit anti-TPA sup * J sup 125 bei SD-Ratten mit Walker-Carcinosarkom und ACI-Ratten mit Blasencarcinom

    Energy Technology Data Exchange (ETDEWEB)

    Quade, A.

    1988-01-21

    A total of sixty-six rats were included in a study on radioimmunodetection. During these experiments, attempts were made on the basis of five different methods were used in an attempt to detect the injected antibodies. These were scintigraphy, flow measurements, activity determinations in both the intracellular and extracellular spaces, autoradiogrammes and PaP staining. The use of a range of various methods of detection turned out to be very advantageous, as the successful visualisation of the tumours in the scintigrammes and their marked activity concentrations of might have been interpreted as an indication of specific binding of anti-TPA to the tumour grafts. The absence of any such specific reactions was, however, quite obvious from the fact that TPA could not be detected in the tumour models used for the same purpose. (orig./MG).

  7. Multiple Merging Events in the Double Cluster A3128/A3125

    Science.gov (United States)

    Rose, James A.; Gaba, Alejandro E.; Christiansen, Wayne A.; Davis, David S.; Caldwell, Nelson; Hunstead, Richard W.; Johnston-Hollitt, Melanie

    2002-03-01

    Multifiber spectroscopy has been obtained for 335 galaxies in the field of the double cluster A3128/A3125, using the 2dF multifiber positioner on the Anglo-Australian Telescope. When combined with previously published results, a total of 532 objects in the double cluster now have known redshifts. We have also obtained a 20 ks Chandra ACIS-I image of the central 16'×16' of A3128 and radio imaging of the cluster with the Molonglo Observatory Synthesis Telescope and the Australia Telescope Compact Array. The spatial/kinematic distribution of redshifts in the field of A3128/A3125, when combined with the Chandra ACIS-I image of A3128, reveals a variety of substructures present in the galaxy distribution and in the hot intracluster medium (ICM). The most striking large-scale feature in the galaxy distribution is a relatively underpopulated redshift zone ~4000 km s-1 on either side of the mean cluster velocity at ~17,500 km s-1. We attribute this depletion zone to the effect of the extensive Horologium-Reticulum (H-R) supercluster, within which A3128/A3125 is embedded. In addition to this large-scale feature, numerous smaller groups of galaxies can be identified, particularly within the underpopulated region within +/-4000 km s-1 of the mean cluster redshift. Because of the large gravitational influence of the H-R supercluster, these groups arrive at A3128 with a high infall velocity, well in excess of the local sound speed. Two of these groups appear as elongated filaments in position-velocity diagrams, indicating that they are tidally distended groups that have been disrupted after a close passage through A3128. In fact, A3125 itself appears to be in such a postpassage condition. We have identified a primary northeast-southwest merger axis connecting A3128 with A3125, along which the filaments are also oriented. In addition, the Chandra image reveals that the X-ray emission is split into two components, each with very small core radii, that are separated by ~1 Mpc

  8. The Origin and Distribution of Heavy Elements in HCG 62

    Science.gov (United States)

    Vrtilek, Jan; Lavoie, Anthony R. (Technical Monitor)

    2000-01-01

    We present recent data on the compact group HCG 62 taken with AXAF CCD Imaging Spectrometer-S (ACIS-S) on Chandra. The sparseness of groups and their relatively simple dynamical history allow the properties of the Intergalatic Medium (IGM) to be more directly related to galaxy evolution than may be possible in clusters, and their lower gas temperatures produce strong lines from a broader range of elements than is the case in hotter clusters. This observation exploits the high X-ray brightness of HCG 62 to determine accurately the abundances of heavy elements as a function of position in the group, to test whether abundance variations are associated with individual galaxies, and to trace the origin of the enrichment.

  9. Multi-wavelength and polarimetric observations of Sagittarius A*

    Energy Technology Data Exchange (ETDEWEB)

    Eckart, A [I. Physikalisches Institut, University of Cologne, Zuelpicher Strasse 77, 50937 Cologne (Germany); Schodel, R [I. Physikalisches Institut, University of Cologne, Zuelpicher Strasse 77, 50937 Cologne (Germany); Meyer, L [I. Physikalisches Institut, University of Cologne, Zuelpicher Strasse 77, 50937 Cologne (Germany); Trippe, S [Max Planck Institut fur extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Ott, T [Max Planck Institut fur extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Genzel, R [Max Planck Institut fur extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Muzic, K [I. Physikalisches Institut, University of Cologne, Zuelpicher Strasse 77, 50937 Cologne (Germany); Moultaka, J [I. Physikalisches Institut, University of Cologne, Zuelpicher Strasse 77, 50937 Cologne (Germany); Straubmeier, C [I. Physikalisches Institut, University of Cologne, Zuelpicher Strasse 77, 50937 Cologne (Germany); Baganoff, F K [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 021 39-4307 (United States); Morris, M [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1547 (United States); Bower, G C [Department of Astronomy and Radio Astronomy Laboratory, University of California at Berkeley, Campbell Hall, Berkeley, CA 94720 (United States)

    2006-12-15

    We summarize the results of some of the latest NIR/sub-millimeter/X-ray observing campaigns. Those include the latest simultaneous observations as well as the most recent results from VLT NACO observations of polarized NIR, flare emission of Sgr A*. We interpret the new NIR, polarimetry results using a model in which spots are on relativistic orbits around Sgr A*, which is associated with the massive 3.6 million solar mass black hole at the Galactic Center. In the NIR, the observations have been carried out using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope. In the X-ray and radio domains we used the ACIS-I instrument aboard the Chandra X-ray Observatory and the Submillimeter Array on Mauna Kea, Hawaii, as well as the Very Large Array in New Mexico, respectively.

  10. Spatially-resolved Spectroscopy of the IC443 Pulsar Wind Nebula and Environs

    Science.gov (United States)

    Swartz, D. A.; Weisskopf, M. C.; Zavlin, V. E.; Bucciantini, N.; Clarke, T. E.; Karovska, M.; Pavlov, G. G.; O'Dell, S. L.; vanderHorst, A J.; Yukita, M.

    2013-01-01

    Deep Chandra ACIS observations of the region around the putative pulsar, CXOU J061705.3+222117, in the supernova remnant IC443 reveal, for the first time, a ring-like morphology surrounding the pulsar and a jet-like structure oriented roughly north-south across the ring and through the pulsar location. The observations further confirm that (1) the spectrum and flux of the central object are consistent with a rotation-powered pulsar interpretation, (2) the non-thermal surrounding nebula is likely powered by the pulsar wind, and (3) the thermal-dominated spectrum at greater distances is consistent with emission from the supernova remnant. The cometary shape of the nebula, suggesting motion towards the southwest (or, equivalently, flow of ambient medium to the northeast), appears to be subsonic; there is no evidence for a strong bow shock, and the circular ring is not distorted by motion through the ambient medium.

  11. The Low-Mass Population of NGC2264 and its Coronal Properties.

    Science.gov (United States)

    Sciortino, Salvatore

    2001-09-01

    We propose to perform a Chandra ACIS-I 100 ks observation of the star forming region NGC 2264 (in Monoceros), achieving an unprecedent sensitivity of fx ~ 5e-16 erg cm-2 s-1 (0.1-4 kev), or Lx ~ 4e28 erg s-1 (for the commonly assumed distance of 760 pc). This will allow us to detect more than 85% of NGC 2264 low-mass members at least down to 0.1 Msun and a sizable fraction of even lower mass members making possible: 1) to derive a reliable Initial Mass Function (IMF) at the very low-mass end, 2) to investigate the role of magnetic fields in the formation process and resulting IMF, 3) to test the coronal emission level of young brown dwarfs, 4) to study the relation between coronal emission level and PMS evolution during the first 3-10 millon year of stellar lifetime.

  12. A Deep X-ray Search for the Putative IMBH in Omega Centauri

    Science.gov (United States)

    Haggard, Daryl; Cool, A.; Heinke, C. O.; Cohn, H. N.; Lugger, P. M.; Van Der Marel, R. P.; Anderson, J.

    2013-04-01

    Omega Centauri, the Milky Way's most massive and enigmatic old stellar cluster, offers a treasure trove of astronomical discovery and controversy, including debate about the existence of an intermediate mass black hole (IMBH) buried in the cluster's core. We report preliminary results of deep 290 ksec) Chandra ACIS-I imaging of Omega Cen, which reveals no X-ray source at the cluster center reported by Anderson and van der Marel (2010), or at any other proposed center for the cluster. We discuss the significance of this new X-ray limit for the possible presence of an IMBH in Omega Cen. We also briefly describe our multiwavelength imaging and spectroscopic campaigns, which probe Omega Cen's binary populations, and the light they shed on the cluster's dynamical history.

  13. Outpatient primary stent-PTA in a symptomatic internal carotid artery stenosis under protection; Ambulante primaere Stent-PTA einer symptomatischen Arteria-carotis-interna-Stenose unter Protektion

    Energy Technology Data Exchange (ETDEWEB)

    Andresen, R. [Abt. fuer Bildgebende Diagnostik und Interventionelle Radiologie, Guestrower Krankenhaus (Germany); Roth, M. [Abt. Neurologie, Guestrower Krankenhaus (Germany); Brinckmann, W. [Gefaesschirurgie, Guestrower Krankenhaus (Germany)

    2003-07-01

    In a 69 year old patient, with a symptomatic ICA stenosis a stent implantation was performed under outpatient conditions. An interdisciplinary consensus was reached that the patient was suitable for outpatient therapy. In accordance with the NASCET criteria, the patient was to be classified to the high-risk group. Within 120 days before the intervention, the following clinical symptoms had occurred: 1 TIA, 2 amaurosis fugax. In the diagnostic angiography a right postbulbar ICA stenosis of 97% was verified. The stent application and subsequent PTA were performed under protection using a filter system. The transfemoral route was always fitted with an endovascular closure system. The neck vessels were followed-up by means of colour coded duplex sonography (CCDS) on days 1, 30, 180 and 360. A contrast-medium intensified MRI was performed on the 5{sup th} day post-intervention. The implantation of the stent and PTA were done without any complications. Atheromatous plaque fragments were found in the protection system. A plaque embolism was excluded clinically and in the contrast-medium intensified MRI 5 days after the intervention. After 360 days, no restenosis was found in the CCDS, the ECA was perfused. The method presented is low in complications and shows a high success rate. If patient recruitment is adequate, this intervention can be performed on an outpatient basis. (orig.) [German] Bei einem 69-jaehrigen Patienten mit symptomatischer Arteria-carotis-interna- (ACI-) Stenose erfolgte unter ambulanten Bedingungen eine primaere Stentimplantation. In einem interdisziplinaeren Konsens, bestehend aus interventionellem Radiologen, Neurologen und Gefaesschirurgen, wurde festgelegt, ob der Patient sich fuer eine ambulante Therapie eignet. Gemaess den NASCET-Kriterien war der Patient der High-Risk-Gruppe zuzuordnen. Innerhalb der letzten 120 Tage vor der Intervention traten folgende Symptome auf: 1 TIA, 2 Amaurosis fugax. In der diagnostischen selektiven 4-Gefaess

  14. Long-term Lightcurves of M31 X-ray Sources

    Science.gov (United States)

    Kong, A. K. H.; Garcia, M. R.; Di Stefano, R.; Murray, S. S.; Primini, F. A.

    2001-09-01

    M31 has been monitored by a Chandra GTO program, which used both the HRC and ACIS from 1999 to 2001 and a GO program, which used ACIS-S during 2000-2001. We report here the lightcurves of X-ray sources in M31 during the past two years. X-ray sources in M31, like in our Galaxy, exhibit variability on long timescales (days to months). Some sources also show spectral state transitions, analogous to the soft/hard state of Galactic sources (like Cyg X-1 and GX 339-4). We present a statistical overview and also focus on some particularly interesting classes of sources. Luminous (> 1038 ergs s-1) X-ray sources in M31 are often associated with globular clusters (Di Stefano et al. 2001); some of these luminous sources are variables, and the lightcurves provide clues to the nature of the compact object. We present data on a few intriguing globular cluster sources. We also present the spectral and time evolution of the X-ray transient near the nucleus (CXOGMP J004242.0+411608; Garcia et al. 2000), which has finally turned off after more than one year in outburst. We compare the long-term X-ray lightcurves of M31 sources to those of Galactic sources (obtained by RXTE/ASM). Such a comparison allows us to probe the nature of M31 X-ray sources.

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

    Science.gov (United States)

    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.

  16. Chandra and XMM–Newton Observations of H 2 O Maser Galaxy ...

    Indian Academy of Sciences (India)

    Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately.

  17. Rapports 2016-2017 sur les frais de voyage pour Chandra ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Beata Bialic

    But: Initiation des nouveaux gouverneurs aux impacts de la recherche. Date(s). 2016-08-14 au 2016-08-23. Destination(s). Pérou/Colombie. Billet d'avion. 6 070.40 $. Frais de transport au sol ou autrement. 142.60 $. Frais de logement. 1 512.99 $. Repas et frais divers. 411.51 $. Autre frais. 0.00 $. Total. 8 137.50 $.

  18. Rapports 2016-2017 sur les frais de voyage pour Chandra ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Beata Bialic

    Réunion du Conseil des gouverneurs. Date(s). 2016-06-20 à 2016-06-22. Destination(s). Ottawa. Billet d'avion. 0.00 $. Frais de transport au sol ou autrement. 211.96 $. Frais de logement. 393.40 $. Repas et frais divers. 75.83 $. Autre frais. 0.00 $. Total. 681.19 $. Commentaires. Rapports 2016-2017 sur les frais de voyage ...

  19. Rapports 2016-2017 sur les frais de voyage pour Chandra ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Beata Bialic

    Assister à des réunions internes organisées par le CRDI. Date(s). 2016-08-05. Destination(s). Ottawa. Billet d'avion. 0.00 $. Frais de transport au sol ou autrement. 202.25 $. Frais de logement. 0.00 $. Repas et frais divers. 0.00 $. Autre frais. 0.00 $. Total. 202.25 $. Commentaires. Rapports 2016-2017 sur les frais de voyage ...

  20. Rapport de frais de 2017-2018 pour Chandra Madramootoo | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Total des frais de déplacement : CAD$11,106.78. Réunion du Conseil des gouverneurs. 20 novembre 2017 au 22 novembre 2017. CAD$1,085.10. Constatation de l'impact de la recherche en Afrique de l'Est. 4 juillet 2017 au 11 juillet 2017. CAD$8,095.97. Réunion du Conseil des gouverneurs. 20 juin 2017 au 21 juin ...

  1. Chandra and XMM–Newton Observations of H2O Maser Galaxy Mrk ...

    Indian Academy of Sciences (India)

    Model I: An absorbed thermal model plus power law (Brassington et al. 2007). Model II: A thermal model for soft component and an absorbed power-law for hard component. Model III: A thermal model for soft component and high energy reflect model for hard component (Zhang et al. 2006). 10. 0.01. 2×10 3. 5×10 3 normaliz.

  2. The restless universe understanding X-ray astronomy in the age of Chandra and Newton

    CERN Document Server

    Schlegel, Eric M

    2002-01-01

    This title tells the story of the development and launch of a major space-based telescope, and explains the discoveries of the nature of the universe in the X-ray spectre. The author looks at the brief history of X-ray astronomy to explore what can and has been learnt by using X-ray.

  3. PERAN IBU KARIR DALAM PENDIDIKAN KELUARGA DI LINGKUNGAN PERSIT KARTIKA CHANDRA KIRANA

    Directory of Open Access Journals (Sweden)

    Siwi Astini

    2018-01-01

    Full Text Available Saat ini, peran wanita telah bergeser dari peran tradisional menjadi modern. Dari hanya memiliki peran tradisional untuk melahirkan anak dan mengurus rumah tangga, kini wanita mempunyai peran sosial dimana dapat berkarir dalam bidang kesehatan, ekonomi, sosial, maupun politik dengan didukung pendidikan yang tinggi. Hal ini dapat mengakibatkan terjadinya konflik peran ganda sebagai pekerja dan ibu rumah tangga bagi wanita yang telah berkeluarga, sehingga mudah menimbulkan konflik kepentingan dalam pelaksaan tugasnya sebagai ibu juga sebagai wanita karir. Hal ini membutuhkan kajian yang lebih menyeluruh mengenai bentuk-bentuk permasalahan, solusi dan dampak dari setiap nilai yang berhubungan dengan kehidupan ibu dan dunia pekerjaan. Metode yang digunakan adalah analisis deskriptif kualitatif, sehingga mampu menjelaskan konteks kehidupan keluarga, pendidikan dan kehidupan profesional. Dalam fakta temuan lapangan ditemukan bahwa kehidupan ibu karir telah mampu menjawab tantangan dunia kerja maupun keluarga secara tepat dan seimbang.

  4. 110 1*Atkuru Veera Venkata Naga Krishna Sunil Kumar, 2Chandra ...

    African Journals Online (AJOL)

    of VDL in biological fluids. These include HPLC with amperometry detection [3], HPLC with UV detection [4], HPLC with fluorescence detection. [5], LC-MS [6,7], GC-MS [8,9] and square-wave adsorption ... stability indicating liquid chromatography with. UV detection ... in drug analysis and the spectrophotometric methods ...

  5. Chandra Studies of Planets and Comets in the X-ray

    Science.gov (United States)

    Lisse, Carey; Bhardwaj, A.; Wolk, S. J.; Christian, D. J.; Dennerl, K.; Bodewits, D.; Zurbuchen, T. H.

    2009-09-01

    The discovery of high energy x-ray emission in 1996 from C/1996 B2 (Hyakutake) created a new class of solar system x-ray emitting objects [1]. Subsequent detections of the morphology, spectra, and time dependence of the x-rays from more than 20 comets have shown that the very soft (E Lisse et al., Science 274, 205 (1996)[2] R. Wegmann and K. Dennerl, A&A 430, L33 (2005)[3] D. Bodewits et al., A&A 469, 1183 (2007)[4] A. Bhardwaj et al., PSS 55, 1135 - 1189 (2007)

  6. Chandra Data Analysis of H2O Megamaser Galaxy NGC 4258

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles. © 2017 Indian ...

  7. GAS SLOSHING AND RADIO GALAXY DYNAMICS IN THE CORE OF THE 3C 449 GROUP

    International Nuclear Information System (INIS)

    Lal, Dharam V.; Kraft, Ralph P.; Randall, Scott W.; Forman, William R.; Nulsen, Paul E. J.; Jones, Christine; Roediger, Elke; ZuHone, John A.; Hardcastle, Martin J.; Croston, Judith H.

    2013-01-01

    We present results from a 140 ks Chandra/ACIS-S observation of the hot gas around the canonical FR I radio galaxy 3C 449. An earlier, shorter 30 ks Chandra observation of the group gas showed an unusual entropy distribution and a surface brightness edge in the gas that could be a strong shock around the inner radio lobes. In our deeper data we find no evidence for a temperature increase inside of the brightness edge, but a temperature decrease across part of the edge. This suggests that the edge is a 'sloshing' cold front due to a merger within the last ∼<1.3-1.6 Gyr. Both the northern and southern inner jets are bent slightly to the west in projection as they enter their respective lobes, suggesting that the sloshing core is moving to the east. The straight inner jet flares at approximately the position where it crosses the contact edge, suggesting that the jet is entraining and thermalizing some of the hot gas as it crosses the edge. We also detect filaments of X-ray emission around the southern inner radio jet and lobe which we attribute to low entropy entrained gas. The lobe flaring and gas entrainment were originally predicted in simulations of Loken et al. and are confirmed in our deep observation.

  8. Studying Dust Scattering Halos with Galactic X-ray Binaries

    Science.gov (United States)

    Beeler, Doreen; Corrales, Lia; Heinz, Sebastian

    2018-01-01

    Dust is an important part of the interstellar medium (ISM) and contributes to the formation of stars and planets. Since the advent of modern X-ray telescopes, Galactic X-ray point sources have permitted a closer look at all phases of the ISM. Interstellar metals from oxygen to iron — in both gas and dust form — are responsible for absorption and scattering of X-ray light. Dust scatters the light in a forward direction and creates a diffuse halo image surrounding many bright Galactic X-ray binaries. We use all the bright X-ray point sources available in the Chandra HETG archive to study dust scattering halos from the local ISM. We have described a data analysis pipeline using a combination of the data reduction software CIAO and Python. We compare our results from Chandra HETG and ACIS-I observations of a well studied dust scattering halo around GX 13+1, in order to characterize any systematic errors associated with the HETG data set. We describe how our data products will be used to measure ISM scaling relations for X-ray extinction, dust abundance, and dust-to-metal ratios.

  9. EMISSION LINES BETWEEN 1 AND 2 keV IN COMETARY X-RAY SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, Ian; Christian, Damian J. [Department of Physics and Astronomy, California State University, 18111 Nordhoff Street, Northridge, CA 91330 (United States); Bodewits, Dennis [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Dennerl, Konrad [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, D-85741 Garching Germany (Germany); Lisse, Carey M. [Planetary Exploration Group, Space Department, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 (United States); Wolk, Scott J., E-mail: ian.ewing.794@my.csun.edu, E-mail: daman.christian@csun.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-01-20

    We present the detection of new cometary X-ray emission lines in the 1.0-2.0 keV range using a sample of comets observed with the Chandra X-Ray Observatory and ACIS spectrometer. We have selected five comets from the Chandra sample with good signal-to-noise spectra. The surveyed comets are C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), and C/2008 8P (Tuttle). We modeled the spectra with an extended version of our solar wind charge exchange (SWCX) emission model. Above 1 keV, we find Ikeya-Zhang to have strong emission lines at 1340 and 1850 eV which we identify as being created by SWCX lines of Mg XI and Si XIII, respectively, and weaker emission lines at 1470, 1600, and 1950 eV formed by SWCX of Mg XII, Mg XI, and Si XIV, respectively. The Mg XI and XII and Si XIII and XIV lines are detected at a significant level for the other comets in our sample (LS4, MH, Encke, 8P), and these lines promise additional diagnostics to be included in SWCX models. The silicon lines in the 1700-2000 eV range are detected for all comets, but with the rising background and decreasing cometary emission, we caution that these detections need further confirmation with higher resolution instruments.

  10. Redetermination of ethyl (3a-cis-3a,8b-dihydroxy-2-methyl-4-oxo-3a,8b-dihydro-4H-indeno[1,2-b]furan-3-carboxylate monohydrate

    Directory of Open Access Journals (Sweden)

    P. S. Pereira Silva

    2009-11-01

    Full Text Available The crystal structure of the title compound, C15H14O6·H2O, has been redetermined from single-crystal X-ray data. The structure was originally determined by Peet et al. [J. Heterocycl. Chem. (1995, 32, 33–41] but the atomic coordinates were not reported or deposited in the Cambridge Structural Database. The ethyl substituent is disordered over two sites with refined occupancies of 0.815 (6 and 0.185 (6. The indeno group is almost planar [maximum deviation 0.0922 (14 Å] and makes an angle of 68.81 (4° with the furan ring. The fused ring molecules are assembled in pairs by intermolecular O—H...O hydrogen bonds. The resulting dimers are also hydrogen bonded to the water molecules, forming double-stranded chains running along the a axis.

  11. Monedas de antiguo y nuevo cuño: envilecimiento y reacuñación en el Nuevo Reino de Granada en la segunda mitad del siglo xviii

    Directory of Open Access Journals (Sweden)

    James Vladimir Torres Moreno

    2014-01-01

    Full Text Available The second half of the eighteenth century was a period of major transformations in the colonial economies.The monetary system was not an exception. This paper contributes to the analysis of such variations, examining two aspects of the monetary policy of the Bourbons: the debasement and the recoinage. For this, the currency amounts that agents took to the Nueva Granada mints to be reminted were reconstructed and the incentives that the Crown provided for that operation were analyzed. The results show that both measures altered the composition but not the size of the money supply. Thus, although the new coinage reduced transaction costs, the debasement prevented the currency in circulation to get unified. It was also found that the circulation of silver coins was important despite of the fact that the viceroyalty was a gold-producing economy. Finally, it is argued that both measures affected in different ways the behavior of variables such as inflation, low-denomination coins and the Gresham's law.

  12. Enzymatic Synthesis of Glyserol-Coconut Oil Fatty Acid and Glycerol-Decanoic Acis Ester as Emulsifier and Antimicrobial Agents Using Candida rugosa Lipase EC 3.1.1.3

    Science.gov (United States)

    Handayani, Sri; Putri, Ayu Tanissa Tamara; Setiasih, Siswati; Hudiyono, Sumi

    2018-01-01

    In this research, enzymatic esterification was carried out between glycerol and fatty acid from coconut oil and decanoic acid using n-hexane as solvent. In this reaction Candida rugosa lipase was used as biocatalyst. Optimization esterification reaction was carried out for parameter of the substrate ratio. The mmol ratio between fatty acid and glycerol were used are 1:1, 1:2, 1:3, and 1: 4. The highest conversion percentage obtained at the mole ratio of 1: 4 with the value of 78.5% for the glycerol-decanoic acid ester and 55.4% for the glycerol coconut oil fatty acid ester. Esterification products were characterized by FT-IR. The FT-IR spectrum showed that the ester bond was formed as indicated by the wave number 1750-1739 cm-1. The esterification products were then examined by simple emulsion test and was proved to be an emulsifier. The glycerol-coconut oil fatty acid ester produced higher stability emulsion compare with glycerol decanoic ester. The antimicrobial activity assay using disc diffusion method showed that both glycerol-coconut oil fatty acid ester and glycerol-decanoic ester had the ability inhibiting the growth of Propionibacterium acnes and Staphylococcus epidermidis. Glycerol-decanoic ester shows higher antimicrobial activity than glycerol-coconut oil fatty acid ester.

  13. Una ensoñación reactiva al poder : la crisis de la Logia Virtud en el marco de un conflicto simbólico (1911-1921

    Directory of Open Access Journals (Sweden)

    Martín Muñoz Zafra

    2007-01-01

    Full Text Available Se sostiene en este artículo cómo en un contexto de enfrentamiento clericalanticlerical la quiebra de la logia Virtud se ve asimismo afectada por la disidencia interna. A principios del siglo XX los partidos republicanos locales adquieren relevancia sólo en cuanto se incorporan a una lucha simbólica en búsqueda del progreso y la moralidad.This article argues how the break of lodge Virtud is not only caused by the clericalanticlerical confrontation but by inner dissenters too. In the early 20th century the local republicans parties acquire meaning only insofar as they can be subsumed in a symbolic fight in search of progress and morality.

  14. Keto - enol, imine - enamine, and nitro - aci-nitro tautomerism and their interrelationship in substituted nitroethylenes. Keto, imine, nitro, and vinyl substituent effects, and the importance of H-bonding

    NARCIS (Netherlands)

    Lammertsma, K.; Bharatam, P.V.

    2000-01-01

    Tautomeric isomers and conformers of 2-nitrovinyl alcohol (1), 2-nitrovinylamine (2), and 1-nitropropene (3) are reported at the MP2 and B3LYP levels of theory, using the 6-31G* basis set, with energy evaluation at B3LYP/6-311+G** and G2MP2. The nitroalkenes are the global minima on their respective

  15. Astronomers Go Behind The Milky Way To Solve X-Ray Mystery

    Science.gov (United States)

    2001-08-01

    , conducted in February 2000, lasted 28 hours. The team observed what was known to be a "blank" region of the galactic plane where the Japanese X-ray satellite ASCA had previously observed but found no individual X-ray sources. The team also discovered 36 bright distant galaxies lurking in the background of this section of the galactic plane, while the foreground was devoid of stars or other individual objects emitting X-rays. Chandra, and now the European XMM-Newton satellite, are at long last beginning to collect light from behind our galaxy. X-radiation from the 36 newly discovered galaxies passes through the Milky Way on its journey towards Earth. This light, therefore, carries the imprint of all that it passes through and will allow astronomers to measure the distribution and physical condition of matter in our Galaxy. Participating in the Chandra observation and Science article are Yoshitomo Maeda of Pennsylvania State University; Hidehiro Kaneda of the Institute of Space and Astronautical Science in Japan; and Shigeo Yamauchi of Iwate University in Japan. Chandra observed the galactic plane with its Advanced CCD Imaging Spectrometer (ACIS) instrument, which was developed for NASA by Pennsylvania State University, University Park, and Massachusetts Institute of Technology, Cambridge. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program, and TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA.

  16. 'The Relation of Biology to Astronomy' and Theology: Panspermia and Panentheism; Revolutionary Convergences Advanced by Fred Hoyle and Chandra Wickramasinghe

    Science.gov (United States)

    Walker, Theodore, Jr.

    2012-06-01

    In contrast to the Copernican revolution in astro-geometry, the Hoyle-Wickramasinghe contribution to the recent and continuing revolution in astrobiology - "cometary panspermia" - features astronomy and biology converging toward theology. They employed astro-biotic reasoning (often labeled "anthropic" reasoning) to demonstrate that life is made possible by the deliberate controlling influence of the living all-embracing "intelligent universe." This is consistent with panentheism [pan-en-theos-ism, not pantheism]. As advanced by Hoyle and Wickramasinghe, cometary panspermia is panentheistic. Also, neoclassical panentheism requires generic panspermia, and favors cometary panspermia.

  17. The HEP Game : Simulator Game of Particle Detector & HEP Laboratory Facilities REPORT - Nathaniel Chandra Harjanto - Indonesia- CERN Summer Studentship 2013

    CERN Document Server

    Harjanto, Nathaniel Chandra

    2013-01-01

    Since the discovery of Higgs boson on 4 July 2012, CERN has increased its Outreach aspect to allow more people to gain knowledge about particle physics and the researches related to it especially in CERN. As part of CERN’s Outreach effort to spread the knowledge throughout the world, we work on a collaboration project between ATLAS and LHCb experiments to make a multi-platform game to educate players about particle physics and CERN also let them have fun at the same time so the education process is a lot more effective. The knowledge of Particle Physics is incomprehensible for most people such as children, teenagers, and people in general who are not being specifically a particle physicist. Therefore, there is a need to promote and spread the knowledge on particle physics throughout the world, and CERN as the world leading institution in particle physics research plays an essential role. Particle physics is not a simple matter that is easily understood by most people, thus the challenge is to make an educat...

  18. The HEP Game : Simulator Game of Particle Detector & HEP Laboratory Facilities POSTER - Nathaniel Chandra Harjanto - Indonesia- CERN Summer Studentship 2013

    CERN Document Server

    Harjanto, Nathaniel Chandra

    2013-01-01

    Since the discovery of Higgs boson on 4 July 2012, CERN has increased its Outreach aspect to allow more people to gain knowledge about particle physics and the researches related to it especially in CERN. As part of CERN’s Outreach effort to spread the knowledge throughout the world, we work on a collaboration project between ATLAS and LHCb experiments to make a multi-platform game to educate players about particle physics and CERN also let them have fun at the same time so the education process is a lot more effective. The knowledge of Particle Physics is incomprehensible for most people such as children, teenagers, and people in general who are not being specifically a particle physicist. Therefore, there is a need to promote and spread the knowledge on particle physics throughout the world, and CERN as the world leading institution in particle physics research plays an essential role. Particle physics is not a simple matter that is easily understood by most people, thus the challenge is to make an educat...

  19. The HEP Game : Simulator Game of Particle Detector & HEP Laboratory Facilities PRESENTATION - Nathaniel Chandra Harjanto - Indonesia- CERN Summer Studentship 2013

    CERN Document Server

    Harjanto, Nathaniel Chandra

    2013-01-01

    Since the discovery of Higgs boson on 4 July 2012, CERN has increased its Outreach aspect to allow more people to gain knowledge about particle physics and the researches related to it especially in CERN. As part of CERN’s Outreach effort to spread the knowledge throughout the world, we work on a collaboration project between ATLAS and LHCb experiments to make a multi-platform game to educate players about particle physics and CERN also let them have fun at the same time so the education process is a lot more effective. The knowledge of Particle Physics is incomprehensible for most people such as children, teenagers, and people in general who are not being specifically a particle physicist. Therefore, there is a need to promote and spread the knowledge on particle physics throughout the world, and CERN as the world leading institution in particle physics research plays an essential role. Particle physics is not a simple matter that is easily understood by most people, thus the challenge is to make an educat...

  20. The 26th anniversary outburst of jet-driving symbiotic binary MWC 560: results from Chandra, Swift, and optical spectroscopy

    Science.gov (United States)

    Lucy, Adrian B.; Sokoloski, J. L.; Munari, U.; Kuin, N. P. M.; Darnley, M. J.; Luna, G. J. M.; Knigge, C.; Valisa, P.; Milani, A.

    2016-03-01

    The symbiotic star MWC 560 = V694 Mon, which is believed to usually drive a jet along the line of sight (e.g., Schmid et al. 2001), is undergoing a sustained outburst (ATel #8653) rivaling its previous brightest outburst of 1990 (Tomov et al. 1990, Leibowitz and Formiggini 2015).

  1. Erratum: ``Nuclear Accretion in Galaxies of the Local Universe: Clues from Chandra Observations'' (ApJ, 624, 155 [2005])

    Science.gov (United States)

    Pellegrini, S.

    2006-01-01

    Because of an error at the Press, several instances of m˙ in § 3.4 were incorrectly set as M˙, rendering this passage confusing. The correct full text of § 3.4 is given below, with affected passages underlined. The Press sincerely regrets this error. 3.4. Relationship between Eddington-scaled Quantities Figure 3 shows the relationship between the Eddington-scaled quantities LX,nuc/LEdd and M˙B/M˙Edd (with M˙Edd=LEdd/0.1c2). The reason for plotting Eddington-scaled quantities lies in the possibility of a direct comparison with the predictions of low radiative efficiency advection-dominated accretion flows (ADAFs; Narayan & Yi 1995). These can develop in the conditions of very low m˙ (defined as m˙=M˙/M˙Edd), precisely when m˙Di Matteo et al. 2003). Figure 3 shows that LADAF is in fact much lower than Lacc, so an ADAF may explain the emission level for a few nearby galactic nuclei. However, LADAF is still too high for the emission level of many other nuclei. The most discrepant cases are those of the galaxies in the lower right portion of Figure 3-NGC 4472 and NGC 1399 (see also Loewenstein et al. 2001), NGC 4649, and the Galactic center (e.g., Baganoff et al. 2003; Yuan et al. 2003). Note also how the possibility of an ADAF reproducing the observed values of LX,nuc decreases with increasing M˙B/M˙Edd, since LADAF/LEdd increases steeply as m˙2.

  2. Export fluxes of geochemical solutes in the meltwater stream of Sutri Dhaka Glacier, Chandra basin, Western Himalaya.

    Science.gov (United States)

    Singh, Ajit T; Laluraj, C M; Sharma, Parmanand; Patel, Lavkush K; Thamban, Meloth

    2017-10-12

    The hydrochemistry of meltwater from the Sutri Dhaka Glacier, Western Himalaya, has been studied to understand the influence of the factors controlling the weathering processes of the glaciers during the peak ablation period. The high solar irradiance prompted intense melting, which has raised the stream flow of the glacier. The meltwater has been observed as slightly alkaline (mean pH 8.2) and contains the major anions (HCO 3 -  > SO 4 2-  > NO 3 -  > Cl - ) and cations (Ca 2+  > Mg 2+  > K +  > Na +  > NH 4 + ) with Ca 2+ (78.5%) and HCO 3 - (74.5%) as the dominant species. The piper diagram indicates the category of stream meltwater as Ca 2+ -HCO 3 - type. In addition, it is evident from the Gibbs diagram that the interaction between the meltwater and bedrock controls the ionic concentrations of the glacial meltwater. The high ratio value (~ 0.75) of HCO 3 - /(HCO 3 -  + SO 4 2- ) indicates that the carbonate weathering is dominant. Fe and Al followed by Mn, Sr, and Ti are the most dominant trace elements present in the meltwater. The significant negative correlation exhibited by the major ions and Sr with the discharge is recommended for the enrichment of these solutes during the lean discharge periods. However, the insignificant correlation of Fe, Al, Mn, and Ti with discharge suggests their physicochemical control. The principal component analysis (PCA) carried has highlighted three dominant composites, i.e., the water-rock interaction, atmospheric dust inputs, and physicochemical changes in the meltwater. Hence, the present study elucidates the export of geochemical solutes from Sutri Dhaka Glacier and factors governing the water chemistry, which helps in the better understanding of hydrochemical processes of the Himalayan glaciers and substantial improvement of our understanding about the glacio-hydrological environments and their response in the scenario of global warming.

  3. Superbubbles Bespeak Toil and Trouble

    Science.gov (United States)

    2000-08-01

    enriched with oxygen, iron and other heavy elements. These expanding bubbles, collide and coalesce to form superbubbles that are five thousand light years in diameter. Earlier data from the Rosat X-ray observatory showed extended patches of X-ray light in the Antennae, but according to Fabbiano, "We didn't know for sure that the superbubbles existed." Now scientists know that in addition to the superbubbles, the Antennae contain dozens of bright point-like sources- neutron stars and black holes-- left behind by the flurry of supernova activity. The X-rays from these sources are generated by gas that is heated to tens of millions of degrees Celsius as it streams from nearby companion stars onto neutron stars or into black holes. The ability to observe the neutron star/black hole sources and the superbubbles in the Antennae will enhance astronomers' understanding of the evolution of galaxies over the eons through the interplay of galaxy collisions, star formation, gravity and supernovas. "What we are witnessing with Chandra is galaxy ecology in action," said Andreas Zezas, "Over tens of millions of years, the superbubbles gradually enrich the galaxy's supply of oxygen and other elements, and may provide the energy needed to trigger the collapse of more clouds to form more stars and more supernovas in a continuing cycle of star birth, death and renewal." The next step will be to pin down the temperature and energy content more exactly, and to determine how much iron and other heavy elements are in the bubbles, and do some statistics based on the number of bubbles to refine the "galactic ecology." Chandra observed the Antennae with the Advanced CCD Imaging Spectrometer (ACIS) for 20 hours on December 1, 1999. The ACIS instrument was built for NASA by the Massachusetts Institute of Technology, Cambridge, and Pennsylvania State University, University Park. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, Calif., is

  4. Arcsecond and Sub-arcsedond Imaging with X-ray Multi-Image Interferometer and Imager for (very) small sattelites

    Science.gov (United States)

    Hayashida, K.; Kawabata, T.; Nakajima, H.; Inoue, S.; Tsunemi, H.

    2017-10-01

    The best angular resolution of 0.5 arcsec is realized with the X-ray mirror onborad the Chandra satellite. Nevertheless, further better or comparable resolution is anticipated to be difficult in near future. In fact, the goal of ATHENA telescope is 5 arcsec in the angular resolution. We propose a new type of X-ray interferometer consisting simply of an X-ray absorption grating and an X-ray spectral imaging detector, such as X-ray CCDs or new generation CMOS detectors, by stacking the multi images created with the Talbot interferenece (Hayashida et al. 2016). This system, now we call Multi Image X-ray Interferometer Module (MIXIM) enables arcseconds resolution with very small satellites of 50cm size, and sub-arcseconds resolution with small sattellites. We have performed ground experiments, in which a micro-focus X-ray source, grating with pitch of 4.8μm, and 30 μm pixel detector placed about 1m from the source. We obtained the self-image (interferometirc fringe) of the grating for wide band pass around 10keV. This result corresponds to about 2 arcsec resolution for parrallel beam incidence. The MIXIM is usefull for high angular resolution imaging of relatively bright sources. Search for super massive black holes and resolving AGN torus would be the targets of this system.

  5. Arcus: Exploring the Formation and Evolution of Clusters, Galaxies, and Stars

    Science.gov (United States)

    Smith, Randall K.; Arcus Collaboration

    2017-06-01

    The Large Scale Structure (LSS) of the Universe grew via the gravitational collapse of dark matter, but the visible components that trace the LSS-galaxies, groups and clusters-have a more complex history. Their baryons experience shock heating, radiative cooling and feedback from black holes and star formation, which leave faint signatures of hot (T~10^5-10^8 K), metal-enriched gas in the interstellar and intergalactic media (ISM and IGM). While recent Planck and X-ray studies support this scenario, no current mission possesses the instrumentation necessary to provide direct observational evidence for these “missing baryons." Arcus, a proposed MIDEX mission, leverages recent advances in critical-angle transmission (CAT) gratings and silicon pore optics (SPOs), using CCDs with strong Suzaku heritage and electronics based on the Swift mission; both the spacecraft and mission operations reuse highly successful designs. To be launched in 2023, Arcus will be the only observatory capable of studying, in detail, the hot galactic and intergalactic gas-the dominant baryonic component in the present-day Universe and ultimate reservoir of entropy, metals and the output from cosmic feedback. Its superior soft X-ray sensitivity will complement the forthcoming post-Hitomi and Athena calorimeters, which will have comparably high spectral resolution above 2 keV but poorer spectral resolution than XMM or Chandra in the Arcus bandpass.

  6. THE HOT INTERSTELLAR MEDIUM OF THE INTERACTING GALAXY NGC 4490

    International Nuclear Information System (INIS)

    Richings, A. J.; Fabbiano, G.; Wang Junfeng; Roberts, T. P.

    2010-01-01

    We present an analysis of the hot interstellar medium (ISM) in the spiral galaxy NGC 4490, which is interacting with the irregular galaxy NGC 4485, using ∼100 ks of Chandra ACIS-S observations. The high angular resolution of Chandra enables us to remove discrete sources and perform spatially resolved spectroscopy for the star-forming regions and associated outflows, allowing us to look at how the physical properties of the hot ISM such as temperature, hydrogen column density, and metal abundances vary throughout these galaxies. We find temperatures of >0.41 keV and 0.85 +0.59 -0.12 keV, electron densities of >1.87η -1/2 x 10 -3 cm -3 and 0.21 +0.03 -0.04 η -1/2 x 10 -3 cm -3 , and hot gas masses of >1.1η 1/2 x 10 7 M sun and ∼3.7η 1/2 x 10 7 M sun in the plane and halo of NGC 4490, respectively, where η is the filling factor of the hot gas. The abundance ratios of Ne, Mg, and Si with respect to Fe are found to be consistent with those predicted by theoretical models of type II supernovae (SNe). The thermal energy in the hot ISM is ∼5% of the total mechanical energy input from SNe, so it is likely that the hot ISM has been enriched and heated by type II SNe. The X-ray emission is anticorrelated with the Hα and mid-infrared emission, suggesting that the hot gas is bounded by filaments of cooler ionized hydrogen mixed with warm dust.

  7. Galactic Starburst NGC 3603 from X-Rays to Radio

    Science.gov (United States)

    Moffat, A. F. J.; Corcoran, M. F.; Stevens, I. R.; Skalkowski, G.; Marchenko, S. V.; Muecke, A.; Ptak, A.; Koribalski, B. S.; Brenneman, L.; Mushotzky, R.; hide

    2002-01-01

    NGC 3603 is the most massive and luminous visible starburst region in the Galaxy. We present the first Chandra/ACIS-I X-ray image and spectra of this dense, exotic object, accompanied by deep cm-wavelength ATCA radio image at similar or less than 1 inch spatial resolution, and HST/ground-based optical data. At the S/N greater than 3 level, Chandra detects several hundred X-ray point sources (compared to the 3 distinct sources seen by ROSAT). At least 40 of these sources are definitely associated with optically identified cluster O and WR type members, but most are not. A diffuse X-ray component is also seen out to approximately 2 feet (4 pc) form the center, probably arising mainly from the large number of merging/colliding hot stellar winds and/or numerous faint cluster sources. The point-source X-ray fluxes generally increase with increasing bolometric brightnesses of the member O/WR stars, but with very large scatter. Some exceptionally bright stellar X-ray sources may be colliding wind binaries. The radio image shows (1) two resolved sources, one definitely non-thermal, in the cluster core near where the X-ray/optically brightest stars with the strongest stellar winds are located, (2) emission from all three known proplyd-like objects (with thermal and non-thermal components, and (3) many thermal sources in the peripheral regions of triggered star-formation. Overall, NGC 3603 appears to be a somewhat younger and hotter, scaled-down version of typical starbursts found in other galaxies.

  8. SPT0346-52: NEGLIGIBLE AGN ACTIVITY IN A COMPACT, HYPER-STARBURST GALAXY AT z = 5.7

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jingzhe; Gonzalez, Anthony H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Vieira, J. D.; Sreevani, J. [Department of Astronomy and Department of Physics, University of Illinois, 1002 West Green St., Urbana, IL 61801 (United States); Aravena, M. [Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile); Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Béthermin, M.; Breuck, C. de; Gullberg, B. [European Southern Observatory, Karl Schwarzschild Straße 2, D-85748 Garching (Germany); Bothwell, M. S. [Cavendish Laboratory, University of Cambridge, JJ Thompson Ave, Cambridge CB3 0HA (United Kingdom); Brandt, W. N. [Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802 (United States); Carlstrom, J. E. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Chapman, S. C. [Dalhousie University, Halifax, Nova Scotia (Canada); Hezaveh, Y. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Litke, K.; Marrone, D. P.; Spilker, J. S. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Malkan, M. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); McDonald, M. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 37-582C, Cambridge, MA 02139 (United States); Murphy, E. J., E-mail: jingzhema@ufl.edu [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); and others

    2016-12-01

    We present Chandra ACIS-S and Australia Telescope Compact Array (ATCA) radio continuum observations of the strongly lensed dusty, star-forming galaxy SPT-S J034640-5204.9 (hereafter SPT0346-52) at z = 5.656. This galaxy has also been observed with ALMA, HST , Spitzer , Herschel , Atacama Pathfinder EXperiment, and the Very Large Telescope. Previous observations indicate that if the infrared (IR) emission is driven by star formation, then the inferred lensing-corrected star formation rate (SFR) (∼4500 M {sub ☉} yr{sup −1}) and SFR surface density Σ{sub SFR} (∼2000 M {sub ☉} yr{sup −1} kpc{sup −2}) are both exceptionally high. It remained unclear from the previous data, however, whether a central active galactic nucleus (AGN) contributes appreciably to the IR luminosity. The Chandra upper limit shows that SPT0346-52 is consistent with being star formation dominated in the X-ray, and any AGN contribution to the IR emission is negligible. The ATCA radio continuum upper limits are also consistent with the FIR-to-radio correlation for star-forming galaxies with no indication of an additional AGN contribution. The observed prodigious intrinsic IR luminosity of (3.6 ± 0.3) × 10{sup 13} L {sub ☉} originates almost solely from vigorous star formation activity. With an intrinsic source size of 0.61 ± 0.03 kpc, SPT0346-52 is confirmed to have one of the highest Σ{sub SFR} of any known galaxy. This high Σ{sub SFR}, which approaches the Eddington limit for a radiation pressure supported starburst, may be explained by a combination of very high star formation efficiency and gas fraction.

  9. Characteristic complications after autologous chondrocyte implantation for cartilage defects of the knee joint

    DEFF Research Database (Denmark)

    Niemeyer, Philipp; Pestka, Jan M; Kreuz, Peter C

    2008-01-01

    BACKGROUND: Although autologous chondrocyte implantation (ACI) is a well-established therapy for the treatment of isolated cartilage defects of the knee joint, little is known about typical complications and their treatment after ACI. HYPOTHESIS: Unsatisfactory outcome after ACI is associated...... with technique-related typical complications. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 309 consecutive patients with 349 ACI procedures of the knee joint were analyzed. Three different ACI techniques were used: periosteum-covered ACI in 52 cases (14.9%), Chondrogide (Geistlich...

  10. Coordinated multi-wavelength observations of Sgr A*

    Energy Technology Data Exchange (ETDEWEB)

    Eckart, A; Bertram, T; Koenig, S; Kunneriath, D; Muzic, K [University of Cologne, Zuelpicher Str. 77, D-50937 Cologne (Germany); Schoedel, R [Instituto de AstrofIsica de AndalucIa, Camino Bajo de Huetor 50, 18008 Granada (Spain); Baganoff, F K [Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139-4307 (United States); Morris, M; Mauerhan, J; Meyer, L [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Dovciak, M; Karas, V [Astronomical Institute, Academy of Sciences, BocnI II, CZ-14131 Prague (Czech Republic); Dowries, D [Institut de Radio Astronomie Millimetrique, Domaine Universitaire, 38406 St. Martin d' Heres (France); Duschl, W J [Institut fuer Theoretische Physik und Astrophysik, Christian-Albrechts-Universitaet zu Kiel, Leibnizstr. 15 24118 Kiel (Germany); Krichbaum, T; Lu, R-S [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Krips, M [Harvard-Smithsonian Center for Astrophysics, SMA project, 60 Garden Street, MS 78 Cambridge, MA 02138 (United States); Markoff, S [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Kruislaan 403, 1098SJ Amsterdam (Netherlands); Moultaka, J [Observatoire Midi-Pyrenees, 14, Avenue Edouard Belin, 31400 Toulouse (France); Najarro, F [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, CSIC, Serrano 121, 28006 Madrid (Spain)], E-mail: eckart@phl.uni-koeln.de (and others)

    2008-10-15

    We report on recent near-infrared (NIR) and X-ray observations of Sagittarius A* (Sgr A*), the electromagnetic manifestation of the {approx}4x10{sup 6}M{sub o-dot} super-massive black hole (SMBH) at the Galactic Center. The goal of these coordinated multi-wavelength observations is to investigate the variable emission from Sgr A* in order to obtain a better understanding of the underlying physical processes in the accretion flow/outflow. The observations have been carried out using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope (July 2005, May 2007) and the ACIS-I instrument aboard the Chandra X-ray Observatory (July 2005). We report on a polarized NIR flare synchronous to a 8x10{sup 33} erg/s X-ray flare in July 2005, and a further flare in May 2007 that shows the highest sub-flare to flare contrast observed until now. The observations can be interpreted in the framework of a model involving a temporary disk with a short jet. In the disk component flux density variations can be explained due to hot spots on relativistic orbits around the central SMBH. The variations of the sub-structures of the May 2007 flare are interpreted as a variation of the hot spot structure due to differential rotation within the disk.

  11. X-Ray Analysis of the Proper Motion and Pulsar Wind Nebula for PSR J1741-2054

    Science.gov (United States)

    Auchettl, Katie; Slane, Patrick; Romani, Roger W.; Posselt, Bettina; Pavlov, George G.; Kargaltsev, Oleg; Ng, C-Y.; Temim, Tea; Weisskopf, Martin C.; Bykov, Andrei; hide

    2015-01-01

    We obtained six observations of PSR J1741-2054 using the Chandra ACIS-S detector totaling approx.300 ks. By registering this new epoch of observations to an archival observation taken 3.2 yr earlier using X-ray point sources in the field of view, we have measured the pulsar proper motion at micron = 109 +/- 10 mas yr(exp. -1) in a direction consistent with the symmetry axis of the observed H(alpha) nebula. We investigated the inferred past trajectory of the pulsar but find no compelling association with OB associations in which the progenitor may have originated. We confirm previous measurements of the pulsar spectrum as an absorbed power law with photon index gamma = 2.68 +/- 0.04, plus a blackbody with an emission radius of (4.5(+3.2/-2.5))d(0.38) km, for a DM-estimated distance of 0.38d(0.38) kpc and a temperature of 61.7 +/- 3.0 eV. Emission from the compact nebula is well described by an absorbed power law model with a photon index of gamma = 1.67 +/- 0.06, while the diffuse emission seen as a trail extending northeast of the pulsar shows no evidence of synchrotron cooling. We also applied image deconvolution techniques to search for small-scale structures in the immediate vicinity of the pulsar, but found no conclusive evidence for such structures.

  12. VizieR Online Data Catalog: Spectroscopic survey of ZwCl 0008.8+5215 (Golovich+, 2017)

    Science.gov (United States)

    Golovich, N.; van Weeren, R. J.; Dawson, W. A.; Jee, M. J.; Wittman, D.

    2017-10-01

    We conducted a spectroscopic survey of ZwCl 0008 with the DEIMOS spectrograph on the Keck II telescope over three separate observing runs (2013 January 16, July 14, and September 5); central wavelength of 6700Å and spectral resolution of ~1Å (50km/s). ZwCl 0008 was observed with Subaru/SuprimeCam in two filters. In g, the total integration time was 720s, consisting of four 180s exposures. In r, the total integration time was 2880s, consisting of eight 360s exposures. Two subfields (see Figure 2) of ZwCl 0008 were observed with HST using both Advanced Camera for Surveys (ACS) and WFC3 in parallel during the 2013 October 10 and 2014 January 24 periods under the program HST-GO-13343. Each region was imaged with two orbits of ACS/F814W and two orbits of WFC3/F606W. We obtained 42ks of Chandra/ACIS-I observations of ZwCl 0008 (ObsID: 15318, 17204, 17205) during Cycles 14 and 16. The final exposure-corrected image was made in the 0.5-2.0keV band. ZwCl 0008 was observed with the Jansky Very Large Array in D-array and C-array. All four correlation products were recorded in the 2-4GHz S-band in 2015 Oct 19 and 2014 Oct 9. (1 data file).

  13. X-ray Pulsars Across the Parameter Space of Luminosity, Accretion Mode, and Spin

    Science.gov (United States)

    Laycock, Silas; Yang, Jun; Christodoulou, Dimitris; Coe, Malcolm; Cappallo, Rigel; Zezas, Andreas; Ho, Wynn C. G.; Hong, JaeSub; Fingerman, Samuel; Drake, Jeremy J.; Kretschmar, Peter; Antoniou, Vallia

    2017-08-01

    We present our multi-satellite library of X-ray Pulsar observations to the community, and highlight recent science results. Available at www.xraypulsars.space the library provides a range of high-level data products, including: activity histories, pulse-profiles, phased event files, and a unique pulse-profile modeling interface. The initial release (v1.0) contains some 15 years of RXTE-PCA, Chandra ACIS-I, and XMM-PN observations of the Small Magellanic Cloud, creating a valuable record of pulsar behavior. Our library is intended to enable new progress on fundamental NS parameters and accretion physics. The major motivations are (1) Assemble a large homogeneous sample to enable population statistics. This has so far been used to map the propeller transition, and explore the role of retrograde and pro-grade accretion disks. (2) Obtain pulse-profiles for the same pulsars on many different occasions, at different luminosities and states in order to break model degeneracies. This effort has led to preliminary measurements of the offsets between magnetic and spin axes. With the addition of other satellites, and Galactic pulsars, the library will cover the entire available range of luminosity, variability timescales and accretion regimes.

  14. The All-wavelength Extended Groth Strip International Survey (AEGIS) Data Sets

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.; Guhathakurta, P.; Konidaris, N.; Newman, J.A.; Ashby, M.L.N.; Biggs, A.D.; Barmby, P.; Bundy, K.; Chapman, S.; Coil, A.L.; Conselice, C.; Cooper, M.; Croton,; Eisenhardt, P.; Ellis, R.; Faber, S.; Fang, T.; Fazio, G.G.; Georgakakis, A.; Gerke, B.; Goss, W.M.; /UC, Berkeley, Astron. Dept. /Lick Observ. /LBL, Berkeley

    2006-07-21

    In this the first of a series of ''Letters'', we present a description of the panchromatic data sets that have been acquired in the Extended Groth Strip region of the sky. Our survey, the All-wavelength Extended Groth Strip International Survey (AEGIS), is intended to study the physical properties and evolutionary processes of galaxies at z {approx} 1. It includes the following deep, wide-field imaging data sets: Chandra/ACIS{sup 30} X-ray (0.5-10 keV), GALEX{sup 31} ultraviolet (1200-2500 A), CFHT/MegaCam Legacy Survey{sup 32} optical (3600-9000 {angstrom}), CFHT/CFH12K optical (4500-9000 {angstrom}), Hubble Space Telescope/ACS{sup 33} optical (4400-8500 {angstrom}), Palomar/WIRC{sup 34} near-infrared (1.2-2.2 {micro}m), Spitzer/IRAC{sup 35} mid-infrared (3.6-8.0 {micro}m), Spitzer/MIPS far-infrared (24-70 {micro}m), and VLA{sup 36} radio continuum (6-20 cm). In addition, this region of the sky has been targeted for extensive spectroscopy using the DEIMOS spectrograph on the Keck II 10 m telescope{sup 37}. Our survey is compared to other large multiwavelength surveys in terms of depth and sky coverage.

  15. The All-Wavelength Extended Groth Strip International Survey(AEGIS) Data Sets

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.; Guhathakurta, P.; Konidaris, N.P.; Newman, J.A.; Ashby, M.L.N.; Biggs, A.D.; Barmby, P.; Bundy, K.; Chapman, S.C.; Coil,A.L.; Conselice, C.J.; Cooper, M.C.; Croton, D.J.; Eisenhardt, P.R.M.; Ellis, R.S.; Faber, S.M.; Fang, T.; Fazio, G.G.; Georgakakis, A.; Gerke,B.F.; Goss, W.M.; Gwyn, S.; Harker, J.; Hopkins, A.M.; Huang, J.-S.; Ivison, R.J.; Kassin, S.A.; Kirby, E.N.; Koekemoer, A.M.; Koo, D.C.; Laird, E.S.; Le Floc' h, E.; Lin, L.; Lotz, J.M.; Marshall, P.J.; Martin,D.C.; Metevier, A.J.; Moustakas, L.A.; Nandra, K.; Noeske, K.G.; Papovich, C.; Phillips, A.C.; Rich,R. M.; Rieke, G.H.; Rigopoulou, D.; Salim, S.; Schiminovich, D.; Simard, L.; Smail, I.; Small,T.A.; Weiner,B.J.; Willmer, C.N.A.; Willner, S.P.; Wilson, G.; Wright, E.L.; Yan, R.

    2006-10-13

    In this the first of a series of Letters, we present a description of the panchromatic data sets that have been acquired in the Extended Groth Strip region of the sky. Our survey, the All-wavelength Extended Groth Strip International Survey (AEGIS), is intended to study the physical properties and evolutionary processes of galaxies at z{approx}1. It includes the following deep, wide-field imaging data sets: Chandra/ACIS X-ray (0.5-10 keV), GALEX ultraviolet (1200-2500 Angstroms), CFHT/MegaCam Legacy Survey optical (3600-9000 Angstroms), CFHT/CFH12K optical (4500-9000 Angstroms), Hubble Space Telescope/ACS optical (4400-8500 Angstroms), Palomar/WIRC near-infrared (1.2-2.2 {micro}m), Spitzer/IRAC mid-infrared (3.6-8.0 {micro}m), Spitzer/MIPS far-infrared (24-70 {micro}m), and VLA radio continuum (6-20 cm). In addition, this region of the sky has been targeted for extensive spectroscopy using the DEIMOS spectrograph on the Keck II 10 m telescope. Our survey is compared to other large multiwavelength surveys in terms of depth and sky coverage.

  16. An Active Galactic Nucleus Caught in the Act of Turning Off and On

    Science.gov (United States)

    Comerford, Julia; Barrows, R. Scott; Muller-Sanchez, Francisco; Nevin, Rebecca; Greene, Jenny; Pooley, Dave; Stern, Daniel; Harrison, Fiona

    2018-01-01

    We present the first discovery of an active galactic nucleus (AGN) that is turning off and then on again. The AGN resides in the z=0.06 galaxy SDSS J1354+1327 and the episodic nuclear activity is the result of discrete accretion events, which could have been triggered by a past interaction with the companion galaxy that is currently located 12.5 kpc away. We originally targeted SDSS J1354+1327 because its Sloan Digital Sky Survey spectrum has narrow AGN emission lines that exhibit a velocity offset of 69 km/s relative to systemic. To determine the nature of the galaxy and its velocity-offset emission lines, we observed SDSS J1354+1327 with Chandra/ACIS, Hubble Space Telescope/Wide Field Camera 3, Apache Point Observatory optical longslit spectroscopy, and Keck/OSIRIS integral-field spectroscopy. We find a ~10 kpc cone of photoionized gas south of the galaxy center and a ~1 kpc semi-spherical front of shocked gas, which is responsible for the velocity offset in the emission lines, north of the galaxy center. We interpret these two outflows as the result of two separate AGN accretion events; the first AGN outburst created the southern outflow, and then northern shock front. The AGN in SDSS J1354+1327 fits into the broader context of AGN flickering that includes observations of AGN light echoes.

  17. Ground- and space-based study of two globular cluster cataclysmic variables: M22 CV1 and M5 V101

    Science.gov (United States)

    Hourihane, A. P.; Callanan, P. J.; Cool, A. M.; Reynolds, M. T.

    2011-06-01

    As a class of compact binaries with large binding energy, cataclysmic variables (CVs) formed through close encounters play an important role in the dynamical evolution of globular clusters. As part of a systematic search for CVs undergoing dwarf nova (DN) eruptions in globular clusters, our 2004 monitoring programme of M22 detected an outburst of the DN candidate CV1 during May. We implement the ISIS image subtraction routine to obtain a light curve for an outburst of CV1. We present the outburst light curve as well as Hubble Space Telescope/Wide-Field Planetary Camera 2 (WFPC2) photometry in the V, U and near-ultraviolet (nUV) bands and a Chandra/Advanced CCD Imaging Spectrometer (ACIS) spectrum of the object. Our results confirm the DN nature of the outburst and the CV status of the object. We also present the results of a ground-based study of another globular cluster CV, M5 V101 - including quiescent medium-resolution William Herschel Telescope (WHT)/Intermediate dispersion Spectrograph and Imaging System (ISIS) spectroscopy in the B and R bands, displaying prominent Balmer and He I emission, and R-band photometry.

  18. Gamma-ray Bursts May Originate in Star-Forming Regions

    Science.gov (United States)

    2001-04-01

    than that expected by the standard scenario of a fireball in a low-density medium - an important clue that the explosion occurred in a dense region. Next, on February 22, 2001, Piro said that Chandra observations of the burst's afterglow, one of the brightest bursts ever observed by BeppoSAX, provided evidence of a fireball expanding in a very dense gas. These recent results supported data from four other gamma-ray bursts observed by BeppoSAX and Chandra (GRB970508, GRB990705, GRB991216, and GRB000214). In these bursts, Piro and his team found evidence indicating that the burst had encountered an extremely dense gas. The properties of this gas suggest that it originated from a very massive progenitor before it exploded as a gamma-ray burst. A key element in the success of these observations has been the perfect timing and liaison between the two satellites, Chandra and BeppoSAX, according to Piro. Piro is the Mission Scientist for BeppoSAX, the instrument that first detected X-ray afterglows from gamma-ray bursts. Currently, astronomers are not usually notified about gamma-ray bursts until an hour or so after they occur. These bursts last only for a few milliseconds to about a minute, although their afterglow can linger in X-ray and optical light for days or weeks. The HETE-2 satellite, launched in October 2000, and Swift, scheduled for a 2003 launch, will provide nearly instant notification of bursts in action, providing satellites such as Chandra a better opportunity to study the afterglow phenomenon in depth. The ACIS X-ray camera was developed for NASA by Penn State and the Massachusetts Institute of Technology. The High Energy Transmission Grating Spectrometer was built by MIT. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, California, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. Images associated with this

  19. Computerized clinical decision support for medication prescribing and utilization in pediatrics.

    Science.gov (United States)

    Stultz, Jeremy S; Nahata, Milap C

    2012-01-01

    Accurate and informed prescribing is essential to ensure the safe and effective use of medications in pediatric patients. Computerized clinical decision support (CCDS) functionalities have been embedded into computerized physician order entry systems with the aim of ensuring accurate and informed medication prescribing. Owing to a lack of comprehensive analysis of the existing literature, this review was undertaken to analyze the effect of CCDS implementation on medication prescribing and use in pediatrics. A literature search was performed using keywords in PubMed to identify research studies with outcomes related to the implementation of medication-related CCDS functionalities. Various CCDS functionalities have been implemented in pediatric patients leading to different results. Medication dosing calculators have decreased calculation errors. Alert-based CCDS functionalities, such as duplicate therapy and medication allergy checking, may generate excessive alerts. Medication interaction CCDS has been minimally studied in pediatrics. Medication dosing support has decreased adverse drug events, but has also been associated with high override rates. Use of medication order sets have improved guideline adherence. Guideline-based treatment recommendations generated by CCDS functionalities have had variable influence on appropriate medication use, with few studies available demonstrating improved patient outcomes due to CCDS use. Although certain medication-related CCDS functionalities have shown benefit in medication prescribing for pediatric patients, others have resulted in high override rates and inconsistent or unknown impact on patient care. Further studies analyzing the effect of individual CCDS functionalities on safe and effective prescribing and medication use are required.

  20. Dicty_cDB: CFD819 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available CGKLSYEIQKAPKKEKIQPYPIIQRV VPELSKAEILKIVPLVTDWINKSNTTANIEKIAKIY*ciilmilkt**ksatcntynik* Translated Amino Aci...PSVCFVTLPLDLYETNGLTLSGEIVECGKLSYEIQKAPKKEKIQPYPIIQRV VPELSKAEILKIVPLVTDWINKSNTTANIEKIAKIY*ciilmilkt**ksatcnt