WorldWideScience

Sample records for cluster x-ray sources

  1. Globular Cluster X-ray Sources

    CERN Document Server

    Verbunt, F

    2004-01-01

    After a brief historical overview we discuss the luminous X-ray sources in globular clusters of our Galaxy. This is followed by an overview of the very luminous X-ray sources studied in globular clusters of 14 other galaxies, and a discussion of their formation and the relation to X-ray sources outside globular clusters. We describe the discovery and classification of low-luminosity X-ray sources, and end the review with some remarks on the formation and evolution of X-ray sources in globular clusters. Observational results are summarized in three tables. Comments are very welcome. Please send them to F.W.M.Verbunt@astro.uu.nl and lewin@mit.edu.

  2. Globular cluster x-ray sources.

    Science.gov (United States)

    Pooley, David

    2010-04-20

    Globular clusters and x-ray astronomy have a long and fruitful history. Uhuru and OSO-7 revealed highly luminous (> 10(36) ergs(-1)) x-ray sources in globular clusters, and Einstein and ROSAT revealed a larger population of low-luminosity (luminosity sources were low-mass x-ray binaries in outburst and that they were orders of magnitude more abundant per unit mass in globular clusters than in the rest of the galaxy. However, the low-luminosity sources proved difficult to classify. Many ideas were put forth--low-mass x-ray binaries in quiescence (qLMXBs), cataclysmic variables (CVs), active main-sequence binaries (ABs), and millisecond pulsars (MSPs)--but secure identifications were scarce. In ROSAT observations of 55 clusters, about 25 low-luminosity sources were found. Chandra has now observed over 80 Galactic globular clusters, and these observations have revealed over 1,500 x-ray sources. The superb angular resolution has allowed for many counterpart identifications, providing clues to the nature of this population. It is a heterogeneous mix of qLMXBs, CVs, ABs, and MSPs, and it has been shown that the qLMXBs and CVs are both, in part, overabundant like the luminous LMXBs. The number of x-ray sources in a cluster correlates very well with its encounter frequency. This points to dynamical formation scenarios for the x-ray sources and shows them to be excellent tracers of the complicated internal dynamics. The relation between the encounter frequency and the number of x-ray sources has been used to suggest that we have misunderstood the dynamical states of globular clusters.

  3. Globular cluster x-ray sources

    Science.gov (United States)

    Pooley, David

    2010-01-01

    Globular clusters and x-ray astronomy have a long and fruitful history. Uhuru and OSO-7 revealed highly luminous (> 1036 ergs-1) x-ray sources in globular clusters, and Einstein and ROSAT revealed a larger population of low-luminosity (luminosity sources were low-mass x-ray binaries in outburst and that they were orders of magnitude more abundant per unit mass in globular clusters than in the rest of the galaxy. However, the low-luminosity sources proved difficult to classify. Many ideas were put forth—low-mass x-ray binaries in quiescence (qLMXBs), cataclysmic variables (CVs), active main-sequence binaries (ABs), and millisecond pulsars (MSPs)—but secure identifications were scarce. In ROSAT observations of 55 clusters, about 25 low-luminosity sources were found. Chandra has now observed over 80 Galactic globular clusters, and these observations have revealed over 1,500 x-ray sources. The superb angular resolution has allowed for many counterpart identifications, providing clues to the nature of this population. It is a heterogeneous mix of qLMXBs, CVs, ABs, and MSPs, and it has been shown that the qLMXBs and CVs are both, in part, overabundant like the luminous LMXBs. The number of x-ray sources in a cluster correlates very well with its encounter frequency. This points to dynamical formation scenarios for the x-ray sources and shows them to be excellent tracers of the complicated internal dynamics. The relation between the encounter frequency and the number of x-ray sources has been used to suggest that we have misunderstood the dynamical states of globular clusters. PMID:20404204

  4. X-ray sources in globular clusters of other galaxies

    CERN Document Server

    Lewin, W H G; Lewin, Walter H.G.; Verbunt, Frank

    2005-01-01

    A large number of X-ray sources in globular clusters of galaxies other than the Milky Way has been found with Chandra. We discuss three issues relating to these sources. The X-ray luminosity function (XLF) of the sources in globular clusters of M31 is marginally compatible with the XLF of globular clusters of the Milky Way. The individual XLFs of a dozen elliptical galaxies, after correction for incompleteness, are compatible with one another and show no break; however, the XLF found by adding the individual XLFs of elliptical galaxies has a break at L_x about 5x10(38) ergs/s. For the moment there is no evidence for a difference between the XLFs of sources inside and outside globular clusters of elliptical galaxies. It is not (yet?) possible to decide which fraction of low-mass X-ray binaries in elliptical galaxies outside globular clusters have formed inside globular clusters.

  5. X-ray sources and their optical counterparts in the globular cluster M 22

    CERN Document Server

    Webb, N A; Gendre, B; Barret, D; Lasota, J P; Rizzi, L

    2004-01-01

    Using XMM-Newton EPIC imaging data, we have detected 50 low-luminosity X-ray sources in the field of view of M 22, where 5 +/- 3 of these sources are likely to be related to the cluster. Using differential optical photometry, we have identified probable counterparts to those sources belonging to the cluster. Using X-ray spectroscopic and timing studies, supported by the optical colours, we propose that the most central X-ray sources in the cluster are cataclysmic variables, millisecond pulsars, active binaries and a blue straggler. We also identify a cluster of galaxies behind this globular cluster.

  6. X-ray Sources and their Optical Counterparts in the Globular Cluster M4

    CERN Document Server

    Bassa, C; Homer, L; Verbunt, F; Gaensler, B M; Lewin, W H G; Anderson, S F; Margon, B; Kaspi, V M; Van der Klis, M; Bassa, Cees; Pooley, David; Homer, Lee; Verbunt, Frank; Gaensler, Bryan M.; Lewin, Walter H. G.; Anderson, Scott F.; Margon, Bruce; Kaspi, Victoria M.; Klis, Michiel van der

    2004-01-01

    We report on the Chandra X-ray Observatory ACIS-S3 imaging observation of the Galactic globular cluster M4 (NGC 6121). We detect 12 X-ray sources inside the core and 19 more within the cluster half-mass radius. The limiting luminosity of this observation is Lx~10e29 erg/sec for sources associated with the cluster, the deepest X-ray observation of a globular cluster to date. We identify 6 X-ray sources with known objects and use ROSAT observations to show that the brightest X-ray source is variable. Archival data from the Hubble Space Telescope allow us to identify optical counterparts to 16 X-ray sources. Based on the X-ray and optical properties of the identifications and the information from the literature, we classify two (possibly three) sources as cataclysmic variables, one X-ray source as a millisecond pulsar and 12 sources as chromospherically active binaries. Comparison of M4 with 47 Tuc and NGC 6397 suggests a scaling of the number of active binaries in these clusters with the cluster (core) mass.

  7. Faint X-ray Sources in the Globular Cluster Terzan 5

    CERN Document Server

    Heinke, C O; Cohn, H N; Lugger, P M; Grindlay, J E; Pooley, D; Lewin, W H G

    2006-01-01

    We report our analysis of a Chandra X-ray observation of the rich globular cluster Terzan 5, in which we detect 50 sources to a limiting 1.0-6 keV X-ray luminosity of 3*10^{31} ergs/s within the half-mass radius of the cluster. Thirty-three of these have L_X>10^{32} ergs/s, the largest number yet seen in any globular cluster. In addition to the quiescent low-mass X-ray binary (LMXB, identified by Wijnands et al.), another 12 relatively soft sources may be quiescent LMXBs. We compare the X-ray colors of the harder sources in Terzan 5 to the Galactic Center sources studied by Muno and collaborators, and find the Galactic Center sources to have harder X-ray colors, indicating a possible difference in the populations. We cannot clearly identify a metallicity dependence in the production of low-luminosity X-ray binaries in Galactic globular clusters, but a metallicity dependence of the form suggested by Jordan et al. for extragalactic LMXBs is consistent with our data.

  8. Interactions between radio sources and X-ray gas at the centers of cooling core clusters

    Science.gov (United States)

    Sarazin, C. L.; Blanton, E. L.; Clarke, T. E.

    Recent Chandra and XMM observations of the interaction of central radio sources and cooling cores in clusters of galaxies will be presented. The clusters studied include A262, A2052, A2626, A113, A2029, A2597, and A4059. The radio sources blow "bubbles" in the X-ray gas, displacing the gas and compressing it into shells around the radio lobes. At the same time, the radio sources are confined by the X-ray gas. At larger radii, "ghost bubbles" are seen which are weak in radio emission except at low frequencies. These may be evidence of previous eruptions of the radio sources. In some cases, buoyantly rising bubbles may entrain cooler X-ray gas from the centers of the cooling cores. Some radio sources previously classified as cluster merger radio relics may actually be displaced radio bubbles from the central radio sources. The relation between the radio bubbles, and cooler gas (10 keV).

  9. Soft x-ray source for nanostructure imaging using femtosecond-laser-irradiated clusters

    Science.gov (United States)

    Fukuda, Y.; Faenov, A. Ya.; Pikuz, T.; Kando, M.; Kotaki, H.; Daito, I.; Ma, J.; Chen, L. M.; Homma, T.; Kawase, K.; Kameshima, T.; Kawachi, T.; Daido, H.; Kimura, T.; Tajima, T.; Kato, Y.; Bulanov, S. V.

    2008-03-01

    The intense soft x-ray light source using the supersonic expansion of the mixed gas of He and CO2, when irradiated by a femtosecond Ti:sapphire laser pulse, is observed to enhance the radiation of soft x-rays from the CO2 clusters. Using this soft x-ray emissions, nanostructure images of 100-nm-thick Mo foils in a wide field of view (mm2 scale) with high spatial resolution (800nm ) are obtained with high dynamic range LiF crystal detectors. The local inhomogeneities of soft x-ray absorption by the nanometer-thick foils is measured with an accuracy of less than ±3%.

  10. A study of diffuse radio sources and X-ray emission in six massive clusters

    CERN Document Server

    Parekh, Viral; Kale, Ruta; Intema, Huib

    2016-01-01

    The goal of the present study is to extend our current knowledge of the diffuse radio source (halo and relic) populations to $z$ $>$ 0.3. Here we report GMRT and EVLA radio observations of six galaxy clusters taken from the MAssive Cluster Survey (MACS) catalogue to detect diffuse radio emission. We used archival GMRT (150, 235 and 610 MHz) and EVLA (L band) data and made images at multiple radio frequencies of the following six clusters - MACSJ0417.5-1154, MACSJ1131.8-1955, MACSJ0308.9+2645, MACSJ2243.3-0935, MACSJ2228.5+2036 and MACSJ0358.8-2955. We detect diffuse radio emission (halo or relic or both) in the first four clusters. In the last two clusters we do not detect any diffuse radio emission but we put stringent upper-limits on their radio powers. We also use archival {\\it Chandra} X-ray data to carry out morphology and substructure analysis of these clusters. We find that based on X-ray data, these MACS clusters are non-relaxed and show substructures in their temperature distribution. The radio power...

  11. A study of diffuse radio sources and X-ray emission in six massive clusters

    Science.gov (United States)

    Parekh, V.; Dwarakanath, K. S.; Kale, R.; Intema, H.

    2017-01-01

    The goal of this study is to extend our current knowledge of the diffuse radio source (halo and relic) populations to z > 0.3. Here, we report GMRT and EVLA radio observations of six galaxy clusters taken from the MAssive Cluster Survey (MACS) catalogue to detect diffuse radio emission. We used archival GMRT (150, 235, and 610 MHz) and EVLA (L band) data and made images at multiple radio frequencies of the following six clusters - MACSJ0417.5-1154, MACSJ1131.8-1955, MACSJ0308.9+2645, MACSJ2243.3-0935, MACSJ2228.5+2036, and MACSJ0358.8-2955. We detect diffuse radio emission (halo or relic, or both) in the first four clusters. In the last two clusters, we do not detect any diffuse radio emission but we put stringent upper limits on their radio powers. We also use archival Chandra X-ray data to carry out morphology and substructure analysis of these clusters. We find that based on X-ray data, these MACS clusters are non-relaxed and show substructures in their temperature distribution. The radio powers of the first four MACS clusters are consistent with their expected values in the LX-P1.4 GHz plot. However, we found ultrasteep spectrum radio halo in the MACSJ0417.5-1154 cluster whose rest-frame cut-off frequency is at ˜900 MHz. The remaining two clusters whose radio powers are ˜11 times below the expected values are most likely to be in the `off-state' as has been postulated in some of the models of radio halo formation.

  12. X-ray Sources and Their Optical Counterparts in the Galactic Globular Cluster M12 (NGC 6218)

    CERN Document Server

    Lu, Ting-Ni; Bassa, Cees; Verbunt, Frank; Lewin, Walter H G; Anderson, Scott F; Pooley, David

    2009-01-01

    We study a Chandra X-ray Observatory ACIS-S observation of the Galactic globular cluster M12. With a 26 ks exposure time, we detect 6 X-ray sources inside the half-mass radius (2'.16) and two of them are inside the core radius (0'.72) of the cluster. If we assume these sources are all within the globular cluster M12, the luminosity Lx among these sources between 0.3-7.0 keV varies roughly from 10^30 to 10^32 ergs s^-1. For identification, we also analyzed the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) data and identified the optical counterparts to five X-ray sources inside the HST field of view. According to the X-ray and optical features, we found 2-5 candidate active binaries (ABs) or cataclysmic variables (CVs) and 0-3 background galaxies within the HST ACS field of view. Based on the assumption that the number of X-ray sources scales with the encounter rate and the mass of the globular cluster, we expect 2 X-ray source inside M12, and the expectation is consistent with our observation...

  13. On the association of the ultraluminous X-ray sources in the Antennae galaxies with young stellar clusters

    CERN Document Server

    Poutanen, Juri; Valeev, Azamat F; Sholukhova, Olga; Greiner, Jochen

    2013-01-01

    The nature of the ultra-luminous X-ray sources (ULXs) in the nearby galaxies is a matter of debates. One of the popular hypothesis associates them with accretion at a sub-Eddington rate on to intermediate mass black holes. Another possibility is a stellar-mass black hole in a high-mass X-ray binary accreting at super-Eddington rates. In this paper we find a highly significant association between brightest X-ray sources in the Antennae galaxies and stellar clusters. On the other hand, we show that most of the X-ray sources are located outside of these clusters. We study clusters associated with the ULXs using the ESO Very Large Telescope spectra and the Hubble Space Telescope data together with the theoretical evolutionary tracks and determine their ages to be below 5 Myr. This implies that the ULX progenitor masses certainly exceed 40 and for some objects are closer to 100 solar masses. We also estimate the ages of clusters situated close to the less luminous X-ray sources (with luminosity in the range 3x10^3...

  14. X-ray lithography source

    Science.gov (United States)

    Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary

    1991-01-01

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.

  15. A Curious Source of Extended X-ray Emission in the Outskirts of Globular Cluster GLIMPSE-C01

    CERN Document Server

    Mirabal, N

    2009-01-01

    We report the discovery of an unusual source of extended X-ray emission CXOU J184846.3-013040 (`The Stem') located on the outskirts of the globular cluster GLIMPSE-C01. No point-like source falls within the extended emission which has an X-ray luminosity L_X =10^{32} ergs/s and a physical size of 0.1 pc at the inferred distance to the cluster. These X-ray properties are consistent with the pulsar wind nebula (PWN) of an unseen pulsar located within the 95-percent confidence error contour of unidentified Fermi gamma-ray source 0FGL J1848.6-0138. However, we cannot exclude an alternative interpretation that postulates X-ray emission associated with a bow shock produced from the interaction of the globular cluster and interstellar gas in the Galactic plane. Analysis of the X-ray data reveals that `The Stem' is most significant in the 2-5 keV band, which suggests that the emission may be dominated by non-thermal bremsstrahlung from suprathermal electrons at the bow shock. If the bow shock interpretation is correc...

  16. CELESTIAL X-RAY SOURCES.

    Science.gov (United States)

    sources, (4) the physical conditions in the pulsating x-ray source in the Crab Nebula , and (5) miscellaneous related topics. A bibliography of all work performed under the contract is given. (Author)

  17. An XMM-Newton view of the young open cluster NGC 6231 - III. Optically faint X-ray sources

    Science.gov (United States)

    Sana, H.; Rauw, G.; Sung, H.; Gosset, E.; Vreux, J.-M.

    2007-05-01

    We discuss the properties of the X-ray sources with faint optical counterparts in the very young open cluster NGC 6231. From their positions in the Hertzsprung-Russell diagram, we find that the bulk of these objects probably consists of low-mass pre-main-sequence (PMS) stars with masses in the range 0.3-3.0 Msolar. The age distribution of these objects indicates that low-mass star formation in NGC 6231 started more than 10Myr ago and culminated in a starburst-like event about 1-4Myr ago when the bulk of the low-mass PMS stars as well as the massive cluster members formed. We find no evidence for a spatial age gradient that could point towards a sequential star formation process. Only a few X-ray sources have counterparts with a reddening exceeding the average value of the cluster or with infrared colours indicating the presence of a moderate near-IR excess. The X-ray spectra of the brightest PMS sources are best fitted by rather hard thermal plasma models and a significant fraction of these sources display flares in their light curve. The X-ray brightest flaring sources have decay times between 2 and 16ks. The X-ray selected PMS stars in NGC 6231 have logLX/Lbol values that increase strongly with decreasing bolometric luminosity and can reach a saturation level (logLX/Lbol ~ -2.4) for non-flaring sources and even more extreme values during flares. Based on observations with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA). E-mail: hsana@eso.org ‡ FNRS Research Associate (Belgium).

  18. AGN Feedback and Evolution of Radio Sources: Discovery of an X-ray Cluster Associated with z=1 Quasar

    CERN Document Server

    Siemiginowska, A; La Massa, S; Burke, D; Aldcroft, T L; Bechtold, J; Elvis, M; Worrall, D M

    2005-01-01

    We report the first significant detection of an X-ray cluster associated with a powerful (L(bol) ~1e47 erg/sec) radio-loud quasar at high redshift (z=1.06). Diffuse X-ray emission is detected out to ~120 kpc from the CSS quasar 3C 186. A strong Fe-line emission at the z(rest)=1.06 confirms its thermal nature. We find that the CSS radio source is highly overpressured with respect to the thermal cluster medium by ~2-3 orders of magnitude. This provides direct observational evidence that the radio source is not thermally confined as posited in the ``frustrated'' scenario for CSS sources. Instead, the radio source may be young and at an early stage of its evolution. This source provides the first detection of the AGN in outburst in the center of a cooling flow cluster. Powerful radio sources are thought to be triggered by the cooling flows. The evidence for the AGN activity and intermittent outbursts comes from the X-ray morphology of low redshift clusters, which usually do not harbour quasars. 3C186 is a young a...

  19. Spatially Extended 21 cm Signal from Strongly Clustered Uv and X-Ray Sources in the Early Universe

    Science.gov (United States)

    Ahn, Kyungjin; Xu, Hao; Norman, Michael L.; Alvarez, Marcelo A.; Wise, John H.

    2015-03-01

    We present our prediction for the local 21 cm differential brightness temperature (δTb) from a set of strongly clustered sources of Population III (Pop III) and II (Pop II) objects in the early universe, by a numerical simulation of their formation and radiative feedback. These objects are located inside a highly biased environment, which is a rare, high-density peak (“Rarepeak”) extending to ∼7 comoving Mpc. We study the impact of ultraviolet and X-ray photons on the intergalactic medium (IGM) and the resulting δTb, when Pop III stars are assumed to emit X-ray photons by forming X-ray binaries very efficiently. We parameterize the rest-frame spectral energy distribution of X-ray photons, which regulates X-ray photon-trapping, IGM-heating, secondary Lyα pumping and the resulting morphology of δTb. A combination of emission (δTb > 0) and absorption (δTb Frequency Array, Murchison Widefield Array, Precision Array for Probing the Epoch of Reionization) of such rare peaks is found to be difficult due to the rarity of these peaks, and the contribution only by these rare peaks to the total power spectrum remains subdominant compared to that by all astrophysical sources.

  20. SPATIALLY EXTENDED 21 cm SIGNAL FROM STRONGLY CLUSTERED UV AND X-RAY SOURCES IN THE EARLY UNIVERSE

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Kyungjin [Department of Earth Sciences, Chosun University, Gwangju, 501-759 (Korea, Republic of); Xu, Hao; Norman, Michael L. [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Alvarez, Marcelo A. [Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, ON M5S 3H8 (Canada); Wise, John H., E-mail: kjahn@chosun.ac.kr [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332 (United States)

    2015-03-20

    We present our prediction for the local 21 cm differential brightness temperature (δT{sub b}) from a set of strongly clustered sources of Population III (Pop III) and II (Pop II) objects in the early universe, by a numerical simulation of their formation and radiative feedback. These objects are located inside a highly biased environment, which is a rare, high-density peak (“Rarepeak”) extending to ∼7 comoving Mpc. We study the impact of ultraviolet and X-ray photons on the intergalactic medium (IGM) and the resulting δT{sub b}, when Pop III stars are assumed to emit X-ray photons by forming X-ray binaries very efficiently. We parameterize the rest-frame spectral energy distribution of X-ray photons, which regulates X-ray photon-trapping, IGM-heating, secondary Lyα pumping and the resulting morphology of δT{sub b}. A combination of emission (δT{sub b} > 0) and absorption (δT{sub b} < 0) regions appears in varying amplitudes and angular scales. The boost of the signal by the high-density environment (δ ∼ 0.64) and on a relatively large scale combines to make Rarepeak a discernible, spatially extended (θ ∼ 10′) object for 21 cm observation at 13 ≲ z ≲ 17, which is found to be detectable as a single object by SKA with integration time of ∼1000 hr. Power spectrum analysis by some of the SKA precursors (Low Frequency Array, Murchison Widefield Array, Precision Array for Probing the Epoch of Reionization) of such rare peaks is found to be difficult due to the rarity of these peaks, and the contribution only by these rare peaks to the total power spectrum remains subdominant compared to that by all astrophysical sources.

  1. X-ray Spectroscopy of Cooling Cluster

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, J.R.; /SLAC; Fabian, A.C.; /Cambridge U., Inst. of Astron.

    2006-01-17

    We review the X-ray spectra of the cores of clusters of galaxies. Recent high resolution X-ray spectroscopic observations have demonstrated a severe deficit of emission at the lowest X-ray temperatures as compared to that expected from simple radiative cooling models. The same observations have provided compelling evidence that the gas in the cores is cooling below half the maximum temperature. We review these results, discuss physical models of cooling clusters, and describe the X-ray instrumentation and analysis techniques used to make these observations. We discuss several viable mechanisms designed to cancel or distort the expected process of X-ray cluster cooling.

  2. Optical Identification of Multiple Faint X-ray Sources in the Globular Cluster NGC 6752 Evidence for Numerous Cataclysmic Variables

    CERN Document Server

    Pooley, D; Homer, L; Verbunt, F; Anderson, S F; Gaensler, B M; Margon, B; Miller, J; Fox, D W; Kaspi, V M; Van der Klis, M

    2002-01-01

    We report on the Chandra ACIS-S3 imaging observation of the globular cluster NGC 6752. We detect 6 X-ray sources within the 10.5" core radius and 13 more within the 115" half-mass radius down to a limiting luminosity of Lx approx 10^{30} erg/s for cluster sources. We reanalyze archival data from the Hubble Space Telescope and the Australia Telescope Compact Array and make 12 optical identifications and one radio identification. Based on X-ray and optical properties of the identifications, we find 10 likely cataclysmic variables (CVs), 1-3 likely RS CVn or BY Dra systems, and 1 or 2 possible background objects. Of the 7 sources for which no optical identifications were made, we expect that ~2-4 are background objects and that the rest are either CVs or some or all of the 5 millisecond pulsars whose radio positions are not yet accurately known. These and other Chandra results on globular clusters indicate that the dozens of CVs per cluster expected by theoretical arguments are finally being found. The findings ...

  3. The ultraluminous X-ray source HoII X-1: kinematic evidence of its escape from the cluster

    CERN Document Server

    Egorov, Oleg V; Moiseev, Alexei V

    2016-01-01

    We analyse the structure and kinematics of ionized gas in the vicinity of the ultraluminous X-ray source (ULX) HoII X-1 in the Holmberg II galaxy using observational data obtained with a scanning Fabry-Perot interferometer in the H$\\alpha$, [SII] and [OIII] emission lines at the Russian 6-m telescope. Decomposition of the line profiles allows us to identify the broad component of emission lines caused by the ULX action. We found evidence of an expanding superbubble around the young star cluster located in the studied region. We conclude that the blue-shifted 'arc' around the ULX observed in the line-of-sight velocity field may correspond to a bow shock caused by the ULX movement from that nearby young star cluster. If this interpretation is correct, it will be the first kinematic evidence of ULX's escape from their parent star clusters.

  4. BeppoSAX spectroscopy of the globular cluster X-ray source X1746-371 (NGC6441)

    CERN Document Server

    Parmar, A N; Guainazzi, M; Segreto, A; Dal Fiume, D; Stella, L

    1999-01-01

    During a BeppoSAX observation of the X-ray source X1746-371 located in the globular cluster NGC6441 a type I X-ray burst, parts of 4 intensity dips, and energy dependent flaring were detected. The dips repeat every 5.8 +0.3 -0.9 hr and show no obvious energy dependence. If the dips are due to electron scattering this energy independence implies an abundance >130 times less than solar, confirming an earlier measurement. Since the overall cluster abundance is close to solar this low abundance is unexpected. Photoionization of the absorbing material, obscuration of an extended source, and variations in multiple components that combine to produce an apparent energy independence are all excluded. Thus, the nature of the dips remains uncertain. The best-fit model to the overall 0.3-30 keV spectrum is a disk-blackbody with a temperature of 2.82 +/- 0.04 keV, together with a cutoff power-law with a photon index of -0.32 +/- 0.80 and a cutoff energy of 0.90 +/- 0.26 keV. Absorption, consistent with the optical extinct...

  5. DYNAMICS INSIDE THE RADIO AND X-RAY CLUSTER CAVITIES OF CYGNUS A AND SIMILAR FRII SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Mathews, William G.; Guo Fulai, E-mail: mathews@ucolick.org [University of California Observatories/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2012-08-10

    We describe approximate axisymmetric computations of the dynamical evolution of material inside radio lobes and X-ray cluster gas cavities in Fanaroff-Riley II (FRII) sources such as Cygnus A. All energy is delivered by a jet to the lobe/cavity via a moving hotspot where jet energy dissipates in a reverse shock. Our calculations describe the evolution of hot plasma, cosmic rays (CRs), and toroidal magnetic fields flowing from the hotspot into the cavity. Many important observational features are explained. Gas, CRs, and field flow back along the cavity surface in a 'boundary backflow' consistent with detailed FRII observations. Computed ages of backflowing CRs are consistent with observed radio-synchrotron age variations only if shear instabilities in the boundary backflow are damped and we assume this is done with viscosity of unknown origin. We compute a faint thermal jet along the symmetry axis and suggest that it is responsible for redirecting the Cygnus A nonthermal jet. Magnetic fields estimated from synchrotron self-Compton (SSC) X-radiation observed near the hotspot evolve into radio lobe fields. Computed profiles of radio-synchrotron lobe emission perpendicular to the jet reveal dramatically limb-brightened emission in excellent agreement with FRII observation, although computed lobe fields exceed those observed. Strong winds flowing from hotspots naturally create kiloparsec-sized spatial offsets between hotspot nonthermal X-ray inverse Compton (IC-CMB) emission and radio-synchrotron emission that peaks 1-2 kpc ahead where the field increases due to wind compression. In our computed version of Cygnus A, nonthermal X-ray emission increases from the hotspot (some IC-CMB, mostly SSC) toward the offset radio-synchrotron peak (mostly SSC).

  6. A Chandra/ACIS Study of 30 Doradus II. X-ray Point Sources in the Massive Star Cluster R136 and Beyond

    CERN Document Server

    Townsley, L K; Feigelson, E D; Garmire, G P; Getman, K V

    2006-01-01

    We have studied the X-ray point source population of the 30 Doradus star-forming complex in the Large Magellanic Cloud using high-spatial-resolution X-ray images and spatially-resolved spectra obtained with the Advanced CCD Imaging Spectrometer (ACIS) aboard the Chandra X-ray Observatory. Here we describe the X-ray sources in a 17' x 17' field centered on R136, the massive star cluster at the center of the main 30 Dor nebula. We detect 20 of the 32 Wolf-Rayet stars in the ACIS field. R136 is resolved at the subarcsecond level into almost 100 X-ray sources, including many typical O3--O5 stars as well as a few bright X-ray sources previously reported. Over two orders of magnitude of scatter in L_X is seen among R136 O stars, suggesting that X-ray emission in the most massive stars depends critically on the details of wind properties and binarity of each system, rather than reflecting the widely-reported characteristic value L_X/L_bol ~ 10^{-7}. Such a canonical ratio may exist for single massive stars in R136, ...

  7. Another Faint UV Object Associated with a Globular Cluster X-Ray Source The Case of M92

    CERN Document Server

    Ferraro, F R; Rood, R T; Pecci, F F; Buonanno, R; Ferraro, Francesco R.; Paltrinieri, Barbara; Rood, Robert T.; Pecci, Flavio Fusi; Buonanno, Roberto

    2000-01-01

    The core of the metal poor Galactic Globular Cluster M92 (NGC 6341) has been observed with WFPC2 on the Hubble Space Telescope through visual, blue and mid-UV filters in a program devoted to study the evolved stellar population in a selected sample of Galactic Globular Clusters. In the UV $(m_{255}, m_{255}-U)$ color magnitude diagram we have discovered a faint `UV-dominant' object. This star lies within the error box of a Low Luminosity Globular Cluster X-ray source (LLGCX) recently found in the core of M92. The properties of the UV star discovered in M92 are very similar to those of other UV stars found in the core of some clusters (M13, 47 Tuc, M80, etc)---all of them are brighter in the UV than in the visible and are located in the vicinity of a LLGCX. We suggest that these stars are a new sub-class of cataclysmic variables.

  8. Accelerator x-ray sources

    CERN Document Server

    Talman, Richard

    2007-01-01

    This first book to cover in-depth the generation of x-rays in particle accelerators focuses on electron beams produced by means of the novel Energy Recovery Linac (ERL) technology. The resulting highly brilliant x-rays are at the centre of this monograph, which continues where other books on the market stop. Written primarily for general, high energy and radiation physicists, the systematic treatment adopted by the work makes it equally suitable as an advanced textbook for young researchers.

  9. Dynamics Inside the Radio and X-ray Cluster Cavities of Cygnus A and Similar FRII Sources

    CERN Document Server

    Mathews, William G

    2012-01-01

    We describe approximate axisymmetric computations of the dynamical evolution of material inside radio lobes and X-ray cluster gas cavities in Fanaroff-Riley II sources such as Cygnus A. All energy is delivered by a jet to the lobe/cavity via a moving hotspot where jet energy dissipates in a reverse shock. Our calculations describe the evolution of hot plasma, cosmic rays (CRs) and toroidal magnetic fields flowing from the hotspot into the cavity. Many observed features are explained. Gas, CRs and field flow back along the cavity surface in a "boundary backflow" consistent with detailed FRII observations. Computed ages of backflowing CRs are consistent with observed radio-synchrotron age variations only if shear instabilities in the boundary backflow are damped and we assume this is done with viscosity of unknown origin. Magnetic fields estimated from synchrotron self-Compton (SSC) X-radiation observed near the hotspot evolve into radio lobe fields. Computed profiles of radio synchrotron lobe emission perpendi...

  10. Accelerator-driven X-ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-09

    After an introduction which mentions x-ray tubes and storage rings and gives a brief review of special relativity, the subject is treated under the following topics and subtopics: synchrotron radiation (bending magnet radiation, wiggler radiation, undulator radiation, brightness and brilliance definition, synchrotron radiation facilities), x-ray free-electron lasers (linac-driven X-ray FEL, FEL interactions, self-amplified spontaneous emission (SASE), SASE self-seeding, fourth-generation light source facilities), and other X-ray sources (energy recovery linacs, Inverse Compton scattering, laser wakefield accelerator driven X-ray sources. In summary, accelerator-based light sources cover the entire electromagnetic spectrum. Synchrotron radiation (bending magnet, wiggler and undulator radiation) has unique properties that can be tailored to the users’ needs: bending magnet and wiggler radiation is broadband, undulator radiation has narrow spectral lines. X-ray FELs are the brightest coherent X-ray sources with high photon flux, femtosecond pulses, full transverse coherence, partial temporal coherence (SASE), and narrow spectral lines with seeding techniques. New developments in electron accelerators and radiation production can potentially lead to more compact sources of coherent X-rays.

  11. The BMW X-ray Cluster Survey

    CERN Document Server

    Moretti, A; Campana, S; Covino, S; Lazzati, D; Longhetti, M; Molinari, E; Panzera, M R; Tagliaferri, G; Dell'Antonio, I P; Moretti, Alberto; Guzzo, Luigi; Campana, Sergio; Covino, Stefano; Lazzati, Davide; Longhetti, Marcella; Molinari, Emilio; Panzera, Maria Rosa; Tagliaferri, Gianpiero; Antonio, Ian Dell'

    2001-01-01

    We describe the main features of the BMW survey of serendipitous X-ray clusters, based on the still unexploited ROSAT-HRI archival observations. The sky coverage, surface density and first deep optical CCD images of the candidates indicate that this sample can represent an excellent complement to the existing PSPC deep cluster surveys and will provide us with a fully independent probe of the evolution of the cluster abundance, in addition to significantly increasing the number of clusters known at z>0.6.

  12. X-ray spectroscopy of manganese clusters

    Energy Technology Data Exchange (ETDEWEB)

    Grush, M.M. [Univ. of California, Davis, CA (United States). Dept. of Applied Science]|[Lawrence Berkeley National Lab., CA (United States). Energy and Environment Div.

    1996-06-01

    Much of this thesis represents the groundwork necessary in order to probe Mn clusters more productively than with conventional Mn K-edge XAS and is presented in Part 1. Part 2 contains the application of x-ray techniques to Mn metalloproteins and includes a prognosis at the end of each chapter. Individual Mn oxidation states are more readily distinguishable in Mn L-edge spectra. An empirical mixed valence simulation routine for determining the average Mn oxidation state has been developed. The first Mn L-edge spectra of a metalloprotein were measured and interpreted. The energy of Mn K{beta} emission is strongly correlated with average Mn oxidation state. K{beta} results support oxidation states of Mn(III){sub 2}(IV){sub 2} for the S{sub 1} state of Photosystem II chemical chemically reduced preparations contain predominantly Mn(II). A strength and limitation of XAS is that it probes all of the species of a particular element in a sample. It would often be advantageous to selectively probe different forms of the same element. The first demonstration that chemical shifts in x-ray fluorescence energies can be used to obtain oxidation state-selective x-ray absorption spectra is presented. Spin-dependent spectra can also be used to obtain a more simplified picture of local structure. The first spin-polarized extended x-ray absorption fine structure using Mn K{beta} fluorescence detection is shown.

  13. The XMM Cluster Survey: X-ray analysis methodology

    CERN Document Server

    Lloyd-Davies, E J; Hosmer, Mark; Mehrtens, Nicola; Davidson, Michael; Sabirli, Kivanc; Mann, Robert G; Hilton, Matt; Liddle, Andrew R; Viana, Pedro T P; Campbell, Heather C; Collins, Chris A; Dubois, E Naomi; Freeman, Peter; Hoyle, Ben; Kay, Scott T; Kuwertz, Emma; Miller, Christopher J; Nichol, Robert C; Sahlen, Martin; Stanford, S Adam; Stott, John P

    2010-01-01

    The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMM- Newton Science Archive. Its main aims are to measure cosmological parameters and trace the evolution of X-ray scaling relations. In this paper we describe the data processing methodology applied to the 5776 XMM observations used to construct the current XCS source catalogue. A total of 3669 > 4-{\\sigma} cluster candidates with >50 background-subtracted X-ray counts are extracted from a total non-overlapping area suitable for cluster searching of 410 deg^2 . Of these, 1022 candidates are detected with >300 X-ray counts, and we demonstrate that robust temperature measurements can be obtained down to this count limit. We describe in detail the automated pipelines used to perform the spectral and surface brightness fitting for these sources, as well as to estimate redshifts from the X-ray data alone. A total of 517 (126) X-ray temperatures to a typical accuracy of <40 (<10) per cent have ...

  14. X-ray galaxy clusters abundance and mass temperature scaling

    CERN Document Server

    Ilic, Stéphane; Douspis, Marian

    2015-01-01

    The abundance of clusters of galaxies is known to be a potential source of cosmological constraints through their mass function. In the present work, we examine the information that can be obtained from the temperature distribution function of X-ray clusters. For this purpose, the mass-temperature ($M$-$T$) relation and its statistical properties are critical ingredients. Using a combination of cosmic microwave background (CMB) data from Planck and our estimations of X-ray cluster abundances, we use Markov chain Monte Carlo (MCMC) techniques to estimate the $\\Lambda$CDM cosmological parameters and the mass to X-ray temperature scaling relation simultaneously. We determine the integrated X-ray temperature function of local clusters using flux-limited surveys. A local comprehensive sample was build from the BAX X-ray cluster database, allowing us to estimate the local temperature distribution function above $\\sim$1 keV. We model the expected temperature function from the mass function and the $M$-$T$ scaling re...

  15. Primordial Globular Clusters, X-Ray Binaries & Cosmological Reionisation

    CERN Document Server

    Power, C; Combet, C; Wilkinson, M I

    2009-01-01

    Globular clusters are dense stellar systems that have typical ages of ~13 billion years, implying that they formed at redshifts of z>~6. Massive stars in newly formed or primordial globular clusters could have played an important role during the epoch of cosmological reionisation (z>~6) as sources of energetic, neutral hydrogen ionising UV photons. We investigate whether or not these stars could have been as important in death as sources of energetic X-ray photons as they were during their main sequence lives. Most massive stars are expected to form in binaries, and an appreciable fraction of these (as much as ~30%) will evolve into X-ray luminous (L_X~10^38 erg/s) high-mass X-ray binaries (HMXBs). These sources would have made a contribution to the X-ray background at z>~6. Using Monte Carlo models of a globular cluster, we estimate the total X-ray luminosity of a population of HMXBs. We compare and contrast this with the total UV luminosity of the massive stars during their main sequence lives. For reasonab...

  16. The Swift X-ray Telescope Cluster Survey III: X-ray spectral analysis

    CERN Document Server

    Tozzi, P; Tundo, E; Liu, T; Rosati, P; Borgani, S; Tagliaferri, G; Campana, S; Fugazza, D; D'Avanzo, P

    2014-01-01

    (Abridged) We present a spectral analysis of a new, flux-limited sample of 72 X-ray selected clusters of galaxies identified with the X-ray Telescope (XRT) on board the Swift satellite down to a flux limit of ~10-14 erg/s/cm2 (SWXCS, Tundo et al. 2012). We carry out a detailed X-ray spectral analysis with the twofold aim of measuring redshifts and characterizing the properties of the Intra-Cluster Medium (ICM). Optical counterparts and spectroscopic or photometric redshifts are obtained with a cross-correlation with NED. Additional photometric redshifts are computed with a dedicated follow-up program with the TNG and a cross-correlation with the SDSS. We also detect the iron emission lines in 35% of the sample, and hence obtain a robust measure of the X-ray redshift zX. We use zX whenever the optical redshift is not available. Finally, for all the sources with measured redshift, background-subtracted spectra are fitted with a mekal model. We perform extensive spectral simulations to derive an empirical formul...

  17. X-ray Counterparts of Millisecond Pulsars in Globular Clusters

    CERN Document Server

    Becker, W; Prinz, T

    2010-01-01

    We have systematically studied the X-ray emission properties of globular cluster millisecond pulsars in order to evaluate their spectral properties and luminosities in a uniform way. Cross-correlating the radio timing positions of the cluster pulsars with the high resolution Chandra images revealed 31 X-ray counterparts identified in nine different globular cluster systems, including those in 47 Tuc. Timing analysis has been performed for all sources corresponding to the temporal resolution available in the archival Chandra data. Making use of unpublished data on M28, M4 and NGC 6752 allowed us to obtain further constraints for the millisecond pulsar counterparts located in these clusters. Counting rate and energy flux upper limits were computed for those 36 pulsars for which no X-ray counterparts could be detected. Comparing the X-ray and radio pulse profiles of PSR J1821-2452 in M28 and the 47 Tuc pulsars PSR J0024-7204D,O,R indicated some correspondence between both wavebands. The X-ray efficiency of the g...

  18. X-Ray Emission from Compact Sources

    Energy Technology Data Exchange (ETDEWEB)

    Cominsky, L

    2004-03-23

    This paper presents a review of the physical parameters of neutron stars and black holes that have been derived from X-ray observations. I then explain how these physical parameters can be used to learn about the extreme conditions occurring in regions of strong gravity, and present some recent evidence for relativistic effects seen in these systems. A glossary of commonly used terms and a short tutorial on the names of X-ray sources are also included.

  19. The discovery of lensed radio and X-ray sources behind the Frontier Fields cluster MACS J0717.5+3745 with the JVLA and Chandra

    CERN Document Server

    van Weeren, R J; Jones, C; Forman, W R; Andrade-Santos, F; Bonafede, A; Brüggen, M; Bulbul, E; Clarke, T E; Churazov, E; David, L; Dawson, W A; Donahue, M; Goulding, A; Kraft, R P; Mason, B; Merten, J; Mroczkowski, T; Murray, S S; Nulsen, P E J; Rosati, P; Roediger, E; Randall, S W; Sayers, J; Umetsu, K; Vikhlinin, A; Zitrin, A

    2015-01-01

    We report on high-resolution JVLA and Chandra observations of the HST Frontier Cluster MACS J0717.5+3745. MACS J0717.5+3745 offers the largest contiguous magnified area of any known cluster, making it a promising target to search for lensed radio and X-ray sources. With the high-resolution 1.0-6.5 GHz JVLA imaging in A and B configuration, we detect a total of 51 compact radio sources within the area covered by the HST imaging. Within this sample we find 7 lensed sources with amplification factors larger than $2$. None of these sources are identified as multiply-lensed. Based on the radio luminosities, the majority of these sources are likely star forming galaxies with star formation rates of 10-50 M$_\\odot$ yr$^{-1}$ located at $1 \\lesssim z \\lesssim 2$. Two of the lensed radio sources are also detected in the Chandra image of the cluster. These two sources are likely AGN, given their $2-10$ keV X-ray luminosities of $\\sim 10^{43-44}$ erg s$^{-1}$. From the derived radio luminosity function, we find evidence...

  20. X-ray source for mammography

    Science.gov (United States)

    Logan, Clinton M.

    1994-01-01

    An x-ray source utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms.

  1. Stellar X-ray Sources in the Rosette Nebula

    Institute of Scientific and Technical Information of China (English)

    W. P. Chen; P. S. Chiang; J. Z. Li

    2004-01-01

    We present optical photometric and spectroscopic studies of ROSAT X-ray stellar sources in the Rosette Nebula star-forming region. The brightest Xray sources are either massive stars or active T Tauri stars associated with the open cluster NGC 2244, or are foreground stars. Some of the spectra of the young stars newly identified in the region are presented.

  2. Cluster X-Ray Substructure and Radio Galaxy Correlations

    Science.gov (United States)

    Ledlow, M. J.; Burns, J. O.

    1994-12-01

    Current wisdom suggests that X-ray substructure in the intracluster medium (ICM) is fairly common in galaxy clusters. This substructure takes the form of elongations, isophotal twisting, asymmetries, and sub-clumping. Substructure is also frequently present in kinematical analysis of the galaxy velocity and spatial distributions. These features include bimodality, kurtosis or skewness, and non-Gaussian velocity distributions. Consistent with the observations, Hydro/N-Body simulations suggest that cluster-subcluster mergers may be the culprit to explain these features in the ICM gas distribution, and would indicate that many clusters, even at the present epoch, are still undergoing significant dynamical evolution. From a sample of X-ray images from the Einstein satellite and, more recently, the ROSAT mission, Burns et al. (1994) found a significant correlation between the positions of radio galaxies and subclumps within the cluster-scale X-ray emission. Burns et al. have suggested that radio galaxies reside in the residue of cluster/sub-cluster merging sites, and may therefore act as pointers to clusters with ongoing and intersting dynamical activity. We are following up these ideas with a detailed substructure analysis, and a comparison to a sample of clusters without radio galaxies. In order to determine the signficance of substructure, we have reanalyzed the X-ray images using a Bootstrap-Resampling Monte-Carlo technique. In this method, asymmetries, elongations, and other forms of substructure are evaluated using a moment-analysis similar to M{o}hr et al. (1994), with the advantage that we need not assume apriori any specific substructure-free model for the source (\\ie\\ a Beta-model). The significance of individual features is determined solely from a comparison to statistical fluctuations (including noise) of the actual data. Using this technique, we place limits on the fraction of clusters with significant substructure and test the radio galaxy

  3. X-ray Binaries in Early Type Galaxies and the Globular Cluster Connection

    NARCIS (Netherlands)

    Maccarone, T.J.; Kundu, A.; Zepf, S.E.; Puzia, T.H.; Tovmassian, G.; Sion, E.

    2004-01-01

    We summarize the key observations made in recent observations of X-ray sources in early-type galaxies. Typically about half of the X-ray binaries in early-type galaxies are in globular clusters, they are preferentially found in metal rich globular clusters, and there is no indication that cluster

  4. Uhuru observations of 4U 1608-52 - The 'steady' X-ray source associated with the X-ray burst source in Norma

    Science.gov (United States)

    Tananbaum, H.; Chaisson, L. J.; Forman, W.; Jones, C.; Matilsky, T. A.

    1976-01-01

    Data are presented for the X-ray source 4U 1608-52, summarizing its light curve, location, and spectral parameters. Evidence is presented showing that this source is the 'steady' X-ray counterpart of the X-ray burst source in Norma. The spectrum of the 'steady' source is compared with the spectrum observed during two bursts, and it is noted that there is substantially more low-energy absorption during the bursts. The 'steady' source spectral data are used to examine the optical data, and it is concluded that if the X-ray spectrum is thermal, then a globular-cluster counterpart probably would have been detected (whereas none has been). Further X-ray and optical observations are suggested for this source, since an optical identification may be central in determining whether all X-ray bursts have a common origin and if this origin requires a globular-cluster environment.

  5. Uhuru observations of 4U 1608-52 - The 'steady' X-ray source associated with the X-ray burst source in Norma

    Science.gov (United States)

    Tananbaum, H.; Chaisson, L. J.; Forman, W.; Jones, C.; Matilsky, T. A.

    1976-01-01

    Data are presented for the X-ray source 4U 1608-52, summarizing its light curve, location, and spectral parameters. Evidence is presented showing that this source is the 'steady' X-ray counterpart of the X-ray burst source in Norma. The spectrum of the 'steady' source is compared with the spectrum observed during two bursts, and it is noted that there is substantially more low-energy absorption during the bursts. The 'steady' source spectral data are used to examine the optical data, and it is concluded that if the X-ray spectrum is thermal, then a globular-cluster counterpart probably would have been detected (whereas none has been). Further X-ray and optical observations are suggested for this source, since an optical identification may be central in determining whether all X-ray bursts have a common origin and if this origin requires a globular-cluster environment.

  6. X-ray observations of eight young open star clusters : I. Membership and X-ray Luminosity

    CERN Document Server

    Bhatt, Himali; Singh, K P; Sagar, Ram; Kumar, Brijesh

    2013-01-01

    We present a detailed investigation of X-ray source contents of eight young open clusters with ages between 4 to 46 Myr using archival X-ray data from XMM-Newton. The probable cluster memberships of the X-ray sources have been established on the basis of multi-wavelength archival data, and samples of 152 pre-main sequence (PMS) low mass ( 10 M_\\odot) stars have been generated. X-ray spectral analyses of high mass stars reveal the presence of high temperature plasma with temperature <2 keV, and mean L_X/L_{bol} of 10^{-6.9}. In the case of PMS low mass stars, the plasma temperatures have been found to be in the range of 0.2 keV to 3 keV with a median value of ~1.3 keV, with no significant difference in plasma temperatures during their evolution from 4 to 46 Myr. The X-ray luminosity distributions of the PMS low mass stars have been found to be similar in the young star clusters under study. This may suggest a nearly uniform X-ray activity in the PMS low mass stars of ages ~4--14 Myr. These observed values o...

  7. Turbulent heating in galaxy clusters brightest in X-rays.

    Science.gov (United States)

    Zhuravleva, I; Churazov, E; Schekochihin, A A; Allen, S W; Arévalo, P; Fabian, A C; Forman, W R; Sanders, J S; Simionescu, A; Sunyaev, R; Vikhlinin, A; Werner, N

    2014-11-06

    The hot (10(7) to 10(8) kelvin), X-ray-emitting intracluster medium (ICM) is the dominant baryonic constituent of clusters of galaxies. In the cores of many clusters, radiative energy losses from the ICM occur on timescales much shorter than the age of the system. Unchecked, this cooling would lead to massive accumulations of cold gas and vigorous star formation, in contradiction to observations. Various sources of energy capable of compensating for these cooling losses have been proposed, the most promising being heating by the supermassive black holes in the central galaxies, through inflation of bubbles of relativistic plasma. Regardless of the original source of energy, the question of how this energy is transferred to the ICM remains open. Here we present a plausible solution to this question based on deep X-ray data and a new data analysis method that enable us to evaluate directly the ICM heating rate from the dissipation of turbulence. We find that turbulent heating is sufficient to offset radiative cooling and indeed appears to balance it locally at each radius-it may therefore be the key element in resolving the gas cooling problem in cluster cores and, more universally, in the atmospheres of X-ray-emitting, gas-rich systems on scales from galaxy clusters to groups and elliptical galaxies.

  8. Jets from ultraluminous X-ray sources

    Science.gov (United States)

    Urquhart, Ryan

    2017-08-01

    An important set of unsolved problems in accretion physics is whether super-Eddington accretion flows produce jets, what the jet power is (compared with the accretion power), and what the large-scale effect of the jet is on the surrounding gas. Most ultraluminous X-ray sources (ULXs) are super-Eddington stellar-mass compact objects: they provide the best local-Universe test of MHD accretion flow simulations. Observational evidence of collimated jets and fast outflows in ULXs may come in different forms: steady synchrotron radio emission from an unresolved, persistent core; radio flaring associated with discrete ejecta; internal shocks along the jet; hotspots from the jet/ISM interaction; hundred-parsec scale wind/jet-inflated nebulae. We discuss examples of the various cases, use them as proxies to measure the jet power, and compare them with (sub-Eddington) AGN and X-ray binary jets.

  9. X-rays from the First Star Clusters

    CERN Document Server

    Oh, S P

    2000-01-01

    Observations of the Ly-alpha forest at z~3 reveal a metallicity Z~0.01 Z(solar). The high-redshift supernovae that polluted the IGM also accelerated relativistic electrons. Since the energy density of the CMB scales as (1+z)^4, at high redshift these electrons cool via inverse Compton scattering. Thus, the first star clusters emit X-rays. Unlike stellar UV ionizing photons, these X-rays can escape easily from their host galaxies. Due to their large mean free path, these X-rays would have reionized the universe in a gradual, homogeneous fashion, regardless of the spatial distribution of sources. In this scenario, the ionization fraction of the single-phase IGM rises gradually, in contrast to canonical models where HII regions expand in a neutral IGM. X-rays also played an important role in reheating the universe to higher temperatures than possible with UV radiation. In particular, they may be responsible for observed Ly-alpha forest line widths in excess of predictions from hydrodynamic simulations. These X-r...

  10. High-intensity X-rays interaction with matter processes in plasmas, clusters, molecules and solids

    CERN Document Server

    Hau-Riege, Stefan P

    2012-01-01

    Filling the need for a book bridging the effect of matter on X-ray radiation and the interaction of x-rays with plasmas, this monograph provides comprehensive coverage of the topic. As such, it presents and explains such powerful new X-ray sources as X-ray free-electron lasers, as well as short pulse interactions with solids, clusters, molecules, and plasmas, and X-ray matter interactions as a diagnostic tool. Equally useful for researchers and practitioners working in the field.

  11. Laser-based X-ray and electron source for X-ray fluorescence studies

    Science.gov (United States)

    Valle Brozas, F.; Crego, A.; Roso, L.; Peralta Conde, A.

    2016-08-01

    In this work, we present a modification to conventional X-rays fluorescence using electrons as excitation source and compare it with the traditional X-ray excitation for the study of pigments. For this purpose, we have constructed a laser-based source capable to produce X-rays as well as electrons. Because of the large penetration depth of X-rays, the collected fluorescence signal is a combination of several material layers of the artwork under study. However, electrons are stopped in the first layers, allowing a more superficial analysis. We show that the combination of both excitation sources can provide extremely valuable information about the structure of the artwork.

  12. IPC two-color analysis of x ray galaxy clusters

    Science.gov (United States)

    White, Raymond E., III

    1990-01-01

    The mass distributions were determined of several clusters of galaxies by using X ray surface brightness data from the Einstein Observatory Imaging Proportional Counter (IPC). Determining cluster mass distributions is important for constraining the nature of the dark matter which dominates the mass of galaxies, galaxy clusters, and the Universe. Galaxy clusters are permeated with hot gas in hydrostatic equilibrium with the gravitational potentials of the clusters. Cluster mass distributions can be determined from x ray observations of cluster gas by using the equation of hydrostatic equilibrium and knowledge of the density and temperature structure of the gas. The x ray surface brightness at some distance from the cluster is the result of the volume x ray emissivity being integrated along the line of sight in the cluster.

  13. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy.

    Science.gov (United States)

    Miaja-Avila, L; O'Neil, G C; Uhlig, J; Cromer, C L; Dowell, M L; Jimenez, R; Hoover, A S; Silverman, K L; Ullom, J N

    2015-03-01

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼10(6) photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >10(7) laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

  14. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    Directory of Open Access Journals (Sweden)

    L. Miaja-Avila

    2015-03-01

    Full Text Available We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

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

    CERN Document Server

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

    2016-01-01

    We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg^2 region around Sgr A* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ~4 x and ~8 x 10^32 erg s^-1 at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources ...

  16. X-ray spectroscopy of clusters of galaxies

    Institute of Scientific and Technical Information of China (English)

    Naomi Ota

    2012-01-01

    Clusters of galaxies are the most massive objects in the Universe and precise knowledge of their mass structure is important to understand the history of structure formation and constrain still unknown types of dark contents of the Universe.X-ray spectroscopy of galaxy clusters provides rich information about the physical state of hot intracluster gas and the underlying potential structure.In this paper,starting from the basic description of clusters under equilibrium conditions,we review properties of clusters revealed primarily through X-ray observations considering their thermal and dynamical evolutions.The future prospects of cluster studies using upcoming X-ray missions are also mentioned.

  17. An Extensive Census of Hubble Space Telescope Counterparts to Chandra X-Ray Sources in the Globular Cluster 47 Tucanae. II. Time Series and Analysis

    Science.gov (United States)

    Edmonds, Peter D.; Gilliland, Ronald L.; Heinke, Craig O.; Grindlay, Jonathan E.

    2003-10-01

    We report time series and variability information for the optical identifications of X-ray sources in 47 Tucanae reported in Paper I (at least 22 cataclysmic variables [CVs] and 29 active binaries). The radial distribution of the CVs is indistinguishable from that of the millisecond pulsars (MSPs) detected by Freire et al. A study of the eight CVs with secure orbital periods (two obtained from the Chandra study of Grindlay et al.) shows that the 47 Tuc CVs have fainter accretion disks, in the V band, than field CVs with similar periods. These faint disks and the faint absolute magnitudes (MV) of the 47 Tuc CVs suggests they have low accretion rates. One possible explanation is that the 47 Tuc objects may be a more representative sample of CVs, down to our detection threshold, than the CVs found in the field (where many low accretion rate systems are believed to be undiscovered), showing the advantages of deep globular cluster observations. The median FX/Fopt value for the 47 Tuc CVs is higher than that of all known classes of field CV, partly because of the faint MV values and partly because of the relatively high X-ray luminosities (LX). The latter are only seen in DQ Her systems in the field, but the 47 Tuc CVs are much fainter optically than most field DQ Her's. Previous work by Edmonds et al. has shown that the four brightest CVs in NGC 6397 have optical spectra and broadband colors that are consistent with DQ Her's having lower than average accretion rates. Some combination of magnetic behavior and low accretion rates may be able to explain our observations, but the results at present are ambiguous, since no class of field CV has distributions of both LX and MV that are consistent with those of the 47 Tuc CVs. The radial distribution of the X-ray detected active binaries is indistinguishable from that of the much larger sample of optical variables (eclipsing and contact binaries and BY Dra variables) detected in previous Wide Field Planetary Camera 2 (WFPC2

  18. Next-generation X-ray cluster surveys

    Science.gov (United States)

    Slack, N. W.; Ponman, T. J.

    2014-03-01

    Contemporary X-ray surveys have permitted rich galaxy clusters to be detected out to redshifts z > 1, but studies with next-generation instruments will allow this work to be extended to both higher redshift and lower cluster masses. Such studies have the potential to provide powerful constraints on the evolution of baryonic processes such as cooling and feedback within developing cosmic structures, provided that observational selection effects can be controlled. To explore this, we generate simulated surveys using the Wide Field Imager (WFI) instrument on International X-ray Observatory (IXO), studied in 2010 by NASA and ESA as a major next-generation X-ray observatory. A sample of observed groups and clusters is assembled and used to derive relationships between temperature and four cluster properties: M500, L500, core radius and β. These are coupled with an evolving population of dark matter haloes drawn from the Millennium Simulation to construct an evolving set of X-ray clusters which are cast into a lightcone and imaged using the main instrumental characteristics of the IXO WFI. State-of-the-art techniques are then employed for source detection and extension testing, to generate a simulated survey cluster catalogue. These simulations are used to explore the dependence of a next-generation survey on the evolution of cluster scaling relations, survey strategy (wide versus deep) and instrument point spread function (PSF). We find that a 1.8 Ms IXO survey gives a cluster sample three to five times larger for a wide survey compared to a deep survey. In both surveys, the strongest discrimination between different LX-T evolutionary models derives from galaxy groups, with T ˜ 1-2 keV. Deep surveys can be affected by cosmic variance within this temperature range, whilst wide surveys suffer from incompleteness, and hence are more vulnerable to biases arising from incomplete knowledge of the survey selection function. Degrading the telescope PSF is found to most

  19. X-ray Observations of Eight Young Open Star Clusters: I. Membership and X-ray Luminosity

    Indian Academy of Sciences (India)

    Himali Bhatt; J. C. Pandey; K. P. Singh; Ram Sagar; Brijesh Kumar

    2013-12-01

    We present a detailed investigation of X-ray source contents of eight young open clusters with ages between 4 to 46 Myr using archival X-ray data from XMM-NEWTON. The probable cluster memberships of the X-ray sources have been established on the basis of multi-wavelength archival data, and samples of 152 pre-main sequence (PMS) low mass (< 2⊙), 36 intermediate mass (2-10⊙) and 16 massive (> 10⊙) stars have been generated. X-ray spectral analyses of high mass stars reveal the presence of high temperature plasma with temperature < 2 keV, and mean /bol of 10-6.9. In the case of PMS low mass stars, the plasma temperatures have been found to be in the range of 0.2 keV to 3 keV with a median value of ∼ 1.3 keV, with no significant difference in plasma temperatures during their evolution from 4 to 46 Myr. The X-ray luminosity distributions of the PMS low mass stars have been found to be similar in the young star clusters under study. This may suggest a nearly uniform X-ray activity in the PMS low mass stars of ages ∼ 4–14 Myr. These observed values of /bol are found to have a mean value of 10-3.6 ± 0.4, which is below the X-ray saturation level. The /bol values for the PMS low mass stars are well correlated with their bolometric luminosities, that implies its dependence on the internal structure of the low mass stars. The difference between the X-ray luminosity distributions of the intermediate mass stars and the PMS low mass stars has not been found to be statistically significant. Their /bol values, however have been found to be significantly different from each other with a confidence level greater than 99.999% and the strength of X-ray activity in the intermediate mass stars is found to be lower compared to the low mass stars. However, the possibility of X-ray emission from the intermediate mass stars due to a low mass star in close proximity of the intermediate mass star can not be ruled out.

  20. The X-ray properties of the young open cluster around alpha Persei

    Science.gov (United States)

    Randich, S.; Schmitt, J. H. M. M.; Prosser, C. F.; Stauffer, J. R.

    1995-01-01

    The observations of the 50 Myr old alpha Persei open cluster, performed by the Rosat's position sensitive proportional counter (PSPC), are discussed. The X-ray observations cover an area of about 10 sq deg. A total of 160 X-ray sources were detected. The comparison between the X-ray luminosity distribution functions of the alpha Persei sample and the Pleiades indicated that F and G-type stars in the alpha Persei are more X-ray luminous than their older counterparts in the Pleiades. No significant difference was found between the distributions of the K and M-type dwarfs in the two clusters.

  1. Compact X-ray Sources in Nearby Galaxy Nuclei

    CERN Document Server

    Colbert, E J M

    1998-01-01

    We have found compact, near-nuclear X-ray sources in 21 (54\\%) of a complete sample of 39 nearby face-on spiral and elliptical galaxies with available ROSAT HRI data. ROSAT X-ray luminosities (0.2 $-$ 2.4 keV) of these compact X-ray sources are $\\sim$10$^{37}

  2. Obscuring Supersoft X-ray Sources in Stellar Winds

    DEFF Research Database (Denmark)

    Nielsen, Mikkel Thomas Bøje; Dominik, Carsten; Nelemans, Gijs

    2011-01-01

    We investigate the possibility of obscuring supersoft X-ray sources in the winds of companion stars. We derive limits on the amount of circumstellar material needed to fully obscure a 'canonical' supersoft X-ray source in the Large Magellanic Cloud, as observed with the Chandra X-ray Observatory....

  3. Nanomaterial-based x-ray sources

    Science.gov (United States)

    Cole, Matthew T.; Parmee, R. J.; Milne, William I.

    2016-02-01

    Following the recent global excitement and investment in the emerging, and rapidly growing, classes of one and two-dimensional nanomaterials, we here present a perspective on one of the viable applications of such materials: field electron emission based x-ray sources. These devices, which have a notable history in medicine, security, industry and research, to date have almost exclusively incorporated thermionic electron sources. Since the middle of the last century, field emission based cathodes were demonstrated, but it is only recently that they have become practicable. We outline some of the technological achievements of the past two decades, and describe a number of the seminal contributions. We explore the foremost market hurdles hindering their roll-out and broader industrial adoption and summarise the recent progress in miniaturised, pulsed and multi-source devices.

  4. Correlation length of X-ray brightest Abell clusters

    CERN Document Server

    Abadi, M G; Muriel, H; Abadi, Mario G; Lambas, Diego G.; Muriel, Hernán

    1998-01-01

    We compute the cluster auto-correlation function $\\xi_{cc}(r)$ of an X-ray flux limited sample of Abell clusters (XBACs, \\cite{ebe}). For the total XBACs sample we find a power-law fit $\\xi_{cc}=(r/r_0)^{\\gamma}$ with $r_0=21.1$ Mpc h$^{-1}$and $\\gamma =-1.9$ consistent with the results of $R \\ge 1 $ Abell clusters. We also analyze $\\xi_{cc}(r)$ for subsamples defined by different X-ray luminosity thresholds where we find a weak tendency of larger values of $r_0$ with increasing X-ray luminosity although with a low statistical significance. In the different subsamples analyzed we find $21 < r_0 < 35 $ Mpc h$^{-1}$ and $-1.9< \\gamma < -1.6$. Our analysis suggests that cluster X-ray luminosities may be used for a reliable confrontation of cluster spatial distribution properties in models and observations.

  5. A deeper look at the X-ray point source population of NGC 4472

    Science.gov (United States)

    Joseph, T. D.; Maccarone, T. J.; Kraft, R. P.; Sivakoff, G. R.

    2017-10-01

    In this paper we discuss the X-ray point source population of NGC 4472, an elliptical galaxy in the Virgo cluster. We used recent deep Chandra data combined with archival Chandra data to obtain a 380 ks exposure time. We find 238 X-ray point sources within 3.7 arcmin of the galaxy centre, with a completeness flux, FX, 0.5-2 keV = 6.3 × 10-16 erg s-1 cm-2. Most of these sources are expected to be low-mass X-ray binaries. We finding that, using data from a single galaxy which is both complete and has a large number of objects (˜100) below 1038 erg s-1, the X-ray luminosity function is well fitted with a single power-law model. By cross matching our X-ray data with both space based and ground based optical data for NGC 4472, we find that 80 of the 238 sources are in globular clusters. We compare the red and blue globular cluster subpopulations and find red clusters are nearly six times more likely to host an X-ray source than blue clusters. We show that there is evidence that these two subpopulations have significantly different X-ray luminosity distributions. Source catalogues for all X-ray point sources, as well as any corresponding optical data for globular cluster sources, are also presented here.

  6. The BMW Deep X-ray Cluster Survey

    CERN Document Server

    Guzzo, L; Campana, S; Covino, S; Dell'Antonio, I P; Lazzati, D; Longhetti, M; Molinari, E; Panzera, M R; Tagliaferri, G

    2001-01-01

    We briefly describe the main features of the Brera Multi-Wavelet (BMW) survey of serendipitous X-ray clusters, based on the still unexploited ROSAT-HRI archival observations. Cluster candidates are selected from the general BMW catalogue of 20,000 sources based exclusively on their X-ray extension. Contrary to common wisdom, a clever selection of the HRI energy channels allows us to significantly reduce the background noise, thus greatly improving the ability to detect low surface-brightness sources as clusters. The resulting sample of ~250 candidates shows a very good sky coverage down to a flux \\~3x10^-14 erg/s/cm^2 ([0.5-2.0] keV band), i.e comparable to existing PSPC-based deep survey, with a particularly interesting area of ~100 sq.deg. around fluxes ~10^-13 erg/s/cm^2, i.e. where highly-luminous, rare systems at z~0.6-1 can be detected. At the same time, the superior angular resolution of the instrument should avoid biases against intrinsically small systems, while easing the identification process (e.g...

  7. Gravitational waves from remnants of ultraluminous X-ray sources

    CERN Document Server

    Hopman, C; Hopman, Clovis; Zwart, Simon Portegies

    2005-01-01

    Ultraluminous X-ray sources (ULXs) with X-ray luminosities larger than the Eddington luminosity of stellar mass objects may be powered by intermediate mass black holes (IBHs) of masses Mbh~10^3Msun. If IBHs form in young dense stellar clusters, they can be fed by Roche lobe overflow from a tidally captured massive (Ms>10Msun) stellar companion. After the donor leaves the main sequence it forms a compact remnant, which spirals in due to gravitational wave (GW) emission. We show that space based detectors such as the Light Interferometer Space Antenna are likely to detect several of these sources. GW sources stemming from this scenario have small eccentricities which give distinct GW signals. Detection of such a GW signal will unambiguously prove the existence of IBHs, and support the hypothesis that some ULXs are powered by IBHs with captured companions.

  8. ROSAT HRI X-ray Observations of the Open Globular Cluster NGC 288

    CERN Document Server

    Sarazin, C L; Rood, R T; Ferraro, F R; Paltrinieri, B; Sarazin, Craig L.; Irwin, Jimmy A.; Rood, Robert T.; Ferraro, Francesco R.; Paltrinieri, Barbara

    1999-01-01

    A ROSAT HRI X-ray image was obtained of the open globular cluster NGC288, which is located near the South Galactic Pole. This is the first deep X-ray image of this system. We detect a Low Luminosity Globular Cluster X-ray source (LLGCX) RXJ005245.0-263449 with an X-ray luminosity of (5.5+-1.4)x10^32 ergs/s (0.1-2.0 keV), which is located very close to the cluster center. There is evidence for X-ray variability on a time scale of <~1 day. The presence of this LLGCX in such an open cluster suggests that dense stellar systems with high interaction rates are not needed to form LLGCXs. HST images will be used to attempt to identify RXJ005245.0-263449. We also searched for diffuse X-ray emission from NGC 288. Upper limits on the X-ray luminosities are L_X^h < 9.5x10^32 ergs/s (0.52-2.02 keV) and L_X^s < 9.3x10^32 ergs/s (0.11-0.41 keV). These imply upper limits to the diffuse X-ray to optical light ratios in NGC 288 which are lower than the values observed for X-ray faint early-type galaxies. This indicate...

  9. X-Ray Scattering Applications Using Pulsed X-Ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Larson, B.C.

    1999-05-23

    Pulsed x-ray sources have been used in transient structural phenomena investigations for over fifty years; however, until the advent of synchrotrons sources and the development of table-top picosecond lasers, general access to ligh temporal resolution x-ray diffraction was relatively limited. Advances in diffraction techniques, sample excitation schemes, and detector systems, in addition to IncEased access to pulsed sources, have ld tO what is now a diverse and growing array of pulsed-source measurement applications. A survey of time-resolved investigations using pulsed x-ray sources is presented and research opportunities using both present and planned pulsed x-ray sources are discussed.

  10. Turbulent Heating in Galaxy Clusters Brightest in X-rays

    CERN Document Server

    Zhuravleva, I; Schekochihin, A A; Allen, S W; Arevalo, P; Fabian, A C; Forman, W R; Sanders, J S; Simionescu, A; Sunyaev, R; Vikhlinin, A; Werner, N

    2014-01-01

    The hot, X-ray-emitting intracluster medium (ICM) is the dominant baryonic constituent of clusters of galaxies. In the cores of many clusters, radiative energy losses from the ICM occur on timescales significantly shorter than the age of the system. Unchecked, this cooling would lead to massive accumulations of cold gas and vigorous star formation, in contradiction to observations. Various sources of energy capable of compensating these cooling losses have been proposed, the most promising being heating by the supermassive black holes in the central galaxies through inflation of bubbles of relativistic plasma. Regardless of the original source of energy, the question of how this energy is transferred to the ICM has remained open. Here we present a plausible solution to this question based on deep Chandra X-ray observatory data and a new data-analysis method that enables us to evaluate directly the ICM heating rate due to the dissipation of turbulence. We find that turbulent heating is sufficient to offset rad...

  11. Identification of Faint Chandra X-ray Sources in the Core-Collapsed Globular Cluster NGC 6397: Evidence for a Bimodal Cataclysmic Variable Population

    CERN Document Server

    Cohn, Haldan N; Couch, Sean M; Anderson, Jay; Cool, Adrienne M; Berg, Maureen van den; Bogdanov, Slavko; Heinke, Craig O; Grindlay, Jonathan E; 10.1088/0004-637X/722/1/20

    2011-01-01

    We have searched for optical identifications for 79 Chandra X-ray sources that lie within the half-mass radius of the nearby, core-collapsed globular cluster NGC 6397, using deep Hubble Space Telescope Advanced Camera for Surveys Wide Field Channel imaging in H-alpha, R, and B. Photometry of these images allows us to classify candidate counterparts based on color-magnitude diagram location. In addition to recovering nine previously detected cataclysmic variables (CVs), we have identified six additional faint CV candidates, a total of 42 active binaries (ABs), two millisecond pulsars (MSPs), one candidate active galactic nucleus, and one candidate interacting galaxy pair. Of the 79 sources, 69 have a plausible optical counterpart. The 15 likely and possible CVs in NGC 6397 mostly fall into two groups: a brighter group of six for which the optical emission is dominated by contributions from the secondary and accretion disk, and a fainter group of seven for which the white dwarf dominates the optical emission. T...

  12. X-ray AGN in the XMM-LSS galaxy clusters: no evidence for AGN suppression

    CERN Document Server

    Koulouridis, E; Melnyk, O; Elyiv, A; Georgantopoulos, I; Clerc, N; Surdej, J; Chiappetti, L; Pierre, M

    2014-01-01

    We present a study of the overdensity of X-ray selected AGN in 33 galaxy clusters in the XMM-LSS field, up to redhift z=1.05. Previous studies have shown that the presence of X-ray selected AGN in rich galaxy clusters is suppressed. In the current study we investigate the occurrence of X-ray selected AGN in low and moderate X-ray luminosity galaxy clusters. Due to the wide contiguous XMM-LSS survey area we are able to extend the study to the cluster outskirts. We therefore determine the projected overdensity of X-ray point-like sources out to 6r_{500} radius. To provide robust statistical results we also use a stacking analysis of the cluster projected overdensities. We investigate whether the observed X-ray overdensities are to be expected by estimating also the corresponding optical galaxy overdensities. We find a positive X-ray projected overdensity at the first radial bin, which is however of the same amplitude as that of optical galaxies. Therefore, no suppression of X-ray AGN activity with respect to th...

  13. X-ray Detection of the Cluster Containing the Cepheid S Mus

    CERN Document Server

    Evans, Nancy Remage; Wolk, Scott J; Guinan, Edward; Engle, Scott; Bond, Howard E; Schaefer, Gail H; Karovska, Margarita; DePasquale, Joseph; Tingle, Evan

    2014-01-01

    The galactic Cepheid S Muscae has recently been added to the important list of Cepheids linked to open clusters, in this case the sparse young cluster ASCC 69. Low-mass members of a young cluster are expected to have rapid rotation and X-ray activity, making X-ray emission an excellent way to discriminate them from old field stars. We have made an XMM-Newton observation centered on S Mus and identified (Table 1) a population of X-ray sources whose near-IR 2MASS counterparts lie at locations in the J, (J-K) color-magnitude diagram consistent with cluster membership at the distance of S Mus. Their median energy and X-ray luminosity are consistent with young cluster members as distinct from field stars. These strengthen the association of S Mus with the young cluster, making it a potential Leavitt Law (Period-Luminosity relation) calibrator.

  14. Laser-based X-ray and electron source for X-ray fluorescence studies

    CERN Document Server

    Brozas, F Valle; Roso, L; Conde, A Peralta

    2016-01-01

    In this work we present a modification to conventional X-rays fluorescence using electrons as excitation source, and compare it with the traditional X-ray excitation for the study of pigments. For this purpose we have constructed a laser-based source capable to produce X-rays as well as electrons. Because of the large penetration depth of X-rays, the collected fluorescence signal is a combination of several material layers of the artwork under study. However electrons are stopped in the first layers allowing therefore a more superficial analysis. We show that the combination of both excitation sources can provide extremely valuable information about the structure of the artwork.

  15. The evolution of galaxy cluster X-ray scaling relations

    CERN Document Server

    Short, C J; Young, O E; Pearce, F R; Jenkins, A; Muanwong, O

    2010-01-01

    We use numerical simulations to investigate, for the first time, the joint effect of feedback from supernovae (SNe) and active galactic nuclei (AGN) on the evolution of galaxy cluster X-ray scaling relations. Our simulations are drawn from the Millennium Gas Project and are some of the largest hydrodynamical N-body simulations ever carried out. Feedback is implemented using a hybrid scheme, where the energy input into intracluster gas by SNe and AGN is taken from a semi-analytic model of galaxy formation. This ensures that the source of feedback is a population of galaxies that closely resembles that found in the real universe. We show that our feedback model is capable of reproducing observed local X-ray scaling laws, at least for non-cool core clusters, but that almost identical results can be obtained with a simplistic preheating model. However, we demonstrate that the two models predict opposing evolutionary behaviour. We have examined whether the evolution predicted by our feedback model is compatible wi...

  16. Infrared Counterparts to Chandra X-Ray Sources in the Antennae

    CERN Document Server

    Clark, D M; Brandl, B R; Wilson, J C; Carson, J C; Henderson, C P; Hayward, T L; Barry, D J; Ptak, A F; Colbert, E J M

    2006-01-01

    We use deep J and Ks images of the Antennae (NGC 4038/9) obtained with WIRC on the Palomar 200-inch telescope, together with the Chandra X-ray source list of Zezas et al. (2002a), to search for IR counterparts to X-ray point sources. We establish an X-ray/IR astrometric frame tie with 0.5" rms residuals over a \\~4.3' field. We find 13 ``strong'' IR counterparts brighter than Ks = 17.8 mag and < 1.0" from X-ray sources, and an additional 6 ``possible'' IR counterparts between 1.0" and 1.5" from X-ray sources. The surface density of IR sources near the X-ray sources suggests only ~2 of the ``strong'' counterparts and ~3 of the ``possible'' counterparts are chance superpositions of unrelated objects. Comparing both strong and possible IR counterparts to our photometric study of ~220 Antennae, IR clusters, we find the IR counterparts to X-ray sources are \\~1.2 mag more luminous in Ks than average non-X-ray clusters. We also note that the X-ray/IR matches are concentrated in the spiral arms and ``overlap'' regi...

  17. Luminous Binary Supersoft X-Ray Sources

    Science.gov (United States)

    Oliversen, Ronald J. (Technical Monitor); DiStefano, Roseanne

    2005-01-01

    One of the key accomplishments of the two preceding years was our development of an algorithm to select SSSs in external galaxies which have been observed by Chandra or XMM-Newton. By applying this algorithm to data from a number of galaxies, we discovered an extension of the class of SSSs to sources that are somewhat harder (100 - 300 eV, instead of tens of eV), but which are nevertheless much softer than canonical X-ray sources. We call these new sources quasisoft sources (QSSs). During this past year, we have built on and extended this work. We have (1) continued to identify SSSs and QSSs in external galaxies, (2) worked on models for the sources and find that black hole models seem promising for a subset of them, and (3) have studied individual systems, especially M101-ULX1. This special system has been observed as an SSS in its high &ate, with a luminosity in excess of 10(exp 41) erg/s. It has also been observed as a QSS when it is less luminous, and as a hard source in its low state. It is one of the best candidates to be an accreting intermediate-mass black hole. We have several papers in preparation. Below we list papers which are complete, including only new work and papers whose status has changed (e.g., been accepted for publication) since our last report. In addition, our work on QSSs has received some publicity. It was the subject of a Chandra press release and was picked up by several media outlets.

  18. Line-Source Based X-Ray Tomography

    Directory of Open Access Journals (Sweden)

    Deepak Bharkhada

    2009-01-01

    Full Text Available Current computed tomography (CT scanners, including micro-CT scanners, utilize a point x-ray source. As we target higher and higher spatial resolutions, the reduced x-ray focal spot size limits the temporal and contrast resolutions achievable. To overcome this limitation, in this paper we propose to use a line-shaped x-ray source so that many more photons can be generated, given a data acquisition interval. In reference to the simultaneous algebraic reconstruction technique (SART algorithm for image reconstruction from projection data generated by an x-ray point source, here we develop a generalized SART algorithm for image reconstruction from projection data generated by an x-ray line source. Our numerical simulation results demonstrate the feasibility of our novel line-source based x-ray CT approach and the proposed generalized SART algorithm.

  19. Stacking Star Clusters in M51: Searching for Faint X-Ray Binaries

    CERN Document Server

    Vulic, N; Gallagher, S C

    2012-01-01

    The population of low-luminosity (< 10^35 erg/s) X-Ray Binaries (XRBs) has been investigated in our Galaxy and M31 but not further. To address this problem, we have used data from the Chandra X-Ray Observatory and the Hubble Space Telescope to investigate the faint population of XRBs in the grand-design spiral galaxy M51. A matching analysis found 25 star clusters coincident with 20 X-ray point sources within 1.5" (60 pc). From X-ray and optical color-color plots we determine that this population is dominated by high-mass XRBs. A stacking analysis of the X-ray data at the positions of optically-identified star clusters was completed to probe low-luminosity X-ray sources. No cluster type had a significant detection in any X-ray energy band. An average globular cluster had the largest upper limit, 9.23 x 10^34 erg/s, in the full-band (0.3 - 8 keV) while on average the complete sample of clusters had the lowest upper limit, 6.46 x 10^33 erg/s in the hard-band (2 - 8 keV). We determined average luminosities of...

  20. Low-luminosity X-ray sources and the Galactic ridge X-ray emission

    CERN Document Server

    Warwick, R S

    2014-01-01

    Using the XMM-Newton Slew Survey, we construct a hard-band selected sample of low-luminosity Galactic X-ray sources. Two source populations are represented, namely coronally-active stars and binaries (ASBs) and cataclysmic variables (CVs), with X-ray luminosities collectively spanning the range 10^(28-34) erg/s (2-10 keV). We derive the 2-10 keV X-ray luminosity function (XLF) and volume emissivity of each population. Scaled to the local stellar mass density, the latter is found to be 1.08 +/- 0.16 x 10^28 erg/s/M and 2.5 +/- 0.6 x 10^27 erg/s/M, for the ASBs and CVs respectively, which in total is a factor 2 higher than previous estimates. We employ the new XLFs to predict the X-ray source counts on the Galactic plane at l = 28.5 deg and show that the result is consistent with current observational constraints. The X-ray emission of faint, unresolved ASBs and CVs can account for a substantial fraction of the Galactic ridge X-ray emission (GRXE). We discuss a model in which roughly 80 per cent of the 6-10 keV...

  1. Bandpass Dependence of X-ray Temperatures in Galaxy Clusters

    CERN Document Server

    Cavagnolo, Kenneth W; Voit, G Mark; Sun, Ming

    2008-01-01

    We explore the band dependence of the inferred X-ray temperature of the intracluster medium (ICM) for 192 well-observed galaxy clusters selected from the Chandra Data Archive. If the hot ICM is nearly isothermal in the projected region of interest, the X-ray temperature inferred from a broad-band (0.7-7.0 keV) spectrum should be identical to the X-ray temperature inferred from a hard-band (2.0-7.0 keV) spectrum. However, if unresolved cool lumps of gas are contributing soft X-ray emission, the temperature of a best-fit single-component thermal model will be cooler for the broad-band spectrum than for the hard-band spectrum. Using this difference as a diagnostic, the ratio of best-fitting hard-band and broad-band temperatures may indicate the presence of cooler gas even when the X-ray spectrum itself may not have sufficient signal-to-noise to resolve multiple temperature components. To test this possible diagnostic, we extract X-ray spectra from core-excised annular regions for each cluster in our archival sam...

  2. Tabletop Ultrabright Kiloelectronvolt X-Ray Sources from Xe and Kr Hollow Atom States

    Science.gov (United States)

    Sankar, Poopalasingam

    Albert Einstein, the father of relativity, once said, "Look deep into nature, and then you will understand everything better". Today available higher resolution tabletop tool to look deep into matters and living thing is an x-ray source. Although the available tabletop x-rays sources of the 20th century, such as the ones used for medical or dental x-rays are tremendously useful for medical diagnostics and industry, a major disadvantage is that they have low quality skillful brightness, which limits its resolution and accuracy. In the other hand, x-ray free-electrons laser (XFEL) and synchrotron radiation sources provided extreme bright x-rays. However, number of applications of XFEL and synchrotron such as medical and industrials, has been hampered by their size, complexity, and cost. This has set a goal of demonstrating x-ray source with enough brightness for potential applications in an often-called tabletop compact x-ray source that could be operated in university laboratory or hospitals. We have developed two tabletop ultrabright keV x-ray sources, one from a Xe hollow-atom states and the other one from Kr hollow-atom stares with a unique characteristic that makes them complementary to currently-available extreme-light sources; XFEL, and synchrotron x-ray source. Upgraded tabletop ultra-fast KrF* pump-laser interacts with target rare-gas clusters and produces hollow-atom states, which later coherently collapse to the empty inner-shell and thereby generate keV x-ray radiation. The KrF* pump-laser beam is self-focused and forms a self-channel to guide the generated x-ray radiation in the direction of the pump-laser beam to produce directed x-ray beam. Xe (M) x-ray source operates at 1.2-1.6 nm wavelength while the Kr(L) x-ray source operates in 600-800 pm wavelength. System is mounted upon 3 optical-tables (5´x12´) with two KrF amplifiers at a repetition rate of 0.1 Hz. A lower bound for brightness value for both Xe and Kr x-ray sources is 1026 photons s-1mm-2

  3. Compact Optical Counterparts of Ultraluminous X-ray Sources

    CERN Document Server

    Tao, Lian; Grise, Fabien; Kaaret, Philip

    2011-01-01

    Using archival Hubble Space Telescope (HST) imaging data, we report the multiband photometric properties of 13 ultraluminous X-ray sources (ULXs) that have a unique compact optical counterpart. Both magnitude and color variation are detected at time scales of days to years. The optical color, variability, and X-ray to optical flux ratio indicate that the optical emission of most ULXs is dominated by X-ray reprocessing on the disk, similar to that of low mass X-ray binaries. For most sources, the optical spectrum is a power-law, $F_{\

  4. An Observational Diagnostic for Ultraluminous X-Ray Sources

    CERN Document Server

    Kalogera, V; Ivanova, N; King, A R

    2004-01-01

    We consider observational tests for the nature of Ultraluminous X-ray sources (ULXs). These must distinguish between thermal-timescale mass transfer on to stellar-mass black holes leading to anisotropic X-ray emission, and accretion on to intermediate-mass black holes. We suggest that long-term transient behavior via the thermal-viscous disk instability could discriminate between these two possibilities for ULXs in regions of young stellar populations. Thermal-timescale mass transfer generally produces stable disks and persistent X-ray emission. In contrast, mass transfer from massive stars to black holes produces unstable disks and thus transient behavior, provided that the black hole mass exceeds some minimum value. This minimum mass depends primarily on the donor mass and evolutionary state. We show that it exceeds 50 solar masses for a large fraction (greater than 90%) of the mass-transfer lifetime for the most likely donors in young clusters. Thus if long-term monitoring reveals a large transient fractio...

  5. Multiwavelength Study of Chandra X-Ray Sources in the Antennae

    CERN Document Server

    Clark, D M; Brandl, B R; Wilson, J C; Carson, J C; Henderson, C P; Hayward, T L; Barry, D J; Ptak, A F; Colbert, E J M

    2010-01-01

    We use WIRC, IR images of the Antennae (NGC 4038/4039) together with the extensive catalogue of 120 X-ray point sources (Zezas et al. 2006) to search for counterpart candidates. Using our proven frame-tie technique, we find 38 X-ray sources with IR counterparts, almost doubling the number of IR counterparts to X-ray sources first identified in Clark et al. (2007). In our photometric analysis, we consider the 35 IR counterparts that are confirmed star clusters. We show that the clusters with X-ray sources tend to be brighter, K_s ~16 mag, with (J-K_s) = 1.1 mag. We then use archival HST images of the Antennae to search for optical counterparts to the X-ray point sources. We employ our previous IR-to-X-ray frame-tie as an intermediary to establish a precise optical-to-X-ray frame-tie with <0.6 arcsec rms positional uncertainty. Due to the high optical source density near the X-ray sources, we determine that we cannot reliably identify counterparts. Comparing the HST positions to the 35 identified IR star clu...

  6. Testing for X-Ray-SZ Differences and Redshift Evolution in the X-Ray Morphology of Galaxy Clusters

    Science.gov (United States)

    Nurgaliev, D.; McDonald, M.; Benson, B. A.; Bleem, L.; Bocquet, S.; Forman, W. R.; Garmire, G. P.; Gupta, N.; Hlavacek-Larrondo, J.; Mohr, J. J.; Nagai, D.; Rapetti, D.; Stark, A. A.; Stubbs, C. W.; Vikhlinin, A.

    2017-05-01

    We present a quantitative study of the X-ray morphology of galaxy clusters, as a function of their detection method and redshift. We analyze two separate samples of galaxy clusters: a sample of 36 clusters at 0.35clusters at 0.25Clusters from both samples have similar-quality Chandra observations, which allow us to quantify their X-ray morphologies via two distinct methods: centroid shifts (w) and photon asymmetry ({A}{phot}). The latter technique provides nearly unbiased morphology estimates for clusters spanning a broad range of redshift and data quality. We further compare the X-ray morphologies of X-ray- and SZ-selected clusters with those of simulated clusters. We do not find a statistically significant difference in the measured X-ray morphology of X-ray and SZ-selected clusters over the redshift range probed by these samples, suggesting that the two are probing similar populations of clusters. We find that the X-ray morphologies of simulated clusters are statistically indistinguishable from those of X-ray- or SZ-selected clusters, implying that the most important physics for dictating the large-scale gas morphology (outside of the core) is well-approximated in these simulations. Finally, we find no statistically significant redshift evolution in the X-ray morphology (both for observed and simulated clusters), over the range of z˜ 0.3 to z˜ 1, seemingly in contradiction with the redshift-dependent halo merger rate predicted by simulations.

  7. Measuring the 3D shape of X-ray clusters

    CERN Document Server

    Samsing, Johan; Hansen, Steen H

    2012-01-01

    Observations and numerical simulations of galaxy clusters strongly indicate that the hot intracluster x-ray emitting gas is not spherically symmetric. In many earlier studies spherical symmetry has been assumed partly because of limited data quality, however new deep observations and instrumental designs will make it possible to go beyond that assumption. Measuring the temperature and density profiles are of interest when observing the x-ray gas, however the spatial shape of the gas itself also carries very useful information. For example, it is believed that the x-ray gas shape in the inner parts of galaxy clusters is greatly affected by feedback mechanisms, cooling and rotation, and measuring this shape can therefore indirectly provide information on these mechanisms. In this paper we present a novel method to measure the three-dimensional shape of the intracluster x-ray emitting gas. We can measure the shape from the x-ray observations only, i.e. the method does not require combination with independent mea...

  8. Chandra X-Ray Sources in the LALA Cetus Field

    Science.gov (United States)

    Wang, J. X.; Zheng, Z. Y.; Malhotra, S.; Finkelstein, S. L.; Rhoads, J. E.; Norman, C. A.; Heckman, T. M.

    2007-11-01

    The 174 ks Chandra Advanced CCD Imaging Spectrometer exposure of the Large Area Lyman Alpha Survey (LALA) Cetus field is the second of the two deep Chandra images on LALA fields. In this paper we present the Chandra X-ray sources detected in the Cetus field, along with an analysis of X-ray source counts, stacked X-ray spectrum, and optical identifications. A total of 188 X-ray sources were detected: 174 in the 0.5-7.0 keV band, 154 in the 0.5-2.0 keV band, and 113 in the 2.0-7.0 keV band. The X-ray source counts were derived and compared with LALA field (172 ks exposure). Interestingly, we find consistent hard-band X-ray source density, but (36+/-12)% higher soft-band X-ray source density in Cetus field. The weighted stacked spectrum of the detected X-ray sources can be fitted by a power law with photon index Γ=1.55. Based on the weighted stacked spectrum, we find that the resolved fraction of the X-ray background drops from (72+/-1)% at 0.5-1.0 keV to (63+/-4)% at 6.0-8.0 keV. The unresolved spectrum can be fitted by a power law over the range 0.5-7 keV, with a photon index Γ=1.22. We also present optical counterparts for 154 of the X-ray sources, down to a limiting magnitude of r'=25.9 (Vega), using a deep r'-band image obtained with the MMT. Optical Observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution.

  9. Testing for X-ray-SZ Differences and Redshift Evolution in the X-ray Morphology of Galaxy Clusters

    CERN Document Server

    Nurgaliev, D; Benson, B A; Bleem, L; Bocquet, S; Forman, W R; Garmire, G P; Gupta, N; Hlavacek-Larrondo, J; Mohr, J J; Nagai, D; Rapetti, D; Stark, A A; Stubbs, C W; Vikhlinin, A

    2016-01-01

    We present a quantitative study of the X-ray morphology of galaxy clusters, as a function of their detection method and redshift. We analyze two separate samples of galaxy clusters: a sample of 36 clusters at 0.35 < z < 0.9 selected in the X-ray with the ROSAT PSPC 400 deg2 survey, and a sample of 90 clusters at 0.25 < z < 1.2 selected via the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope. Clusters from both samples have similar-quality Chandra observations, which allow us to quantify their X-ray morphologies via two distinct methods: centroid shifts and photon asymmetry. The latter technique provides nearly unbiased morphology estimates for clusters spanning a broad range of redshift and data quality. We further compare the X-ray morphologies of X-ray- and SZ-selected clusters with those of simulated clusters. We do not find a statistically significant difference in the measured X-ray morphology of X-ray and SZ-selected clusters over the redshift range probed by these samples, sugg...

  10. X-Ray Imaging Crystal Spectrometer for Extended X-Ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Bitter, Manfred L.; Fraekel, Benjamin; Gorman, James L.; Hill, Kenneth W.; Roquemore, Lane A.; Stodiek, Wolfgang; Goeler, Schweickhard von

    1999-05-01

    Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokamak fusion experiment to provide spatially and temporally resolved data on plasma parameters such as ion temperature, toroidal and poloidal rotation, electron temperature, impurity ion charge-state distributions, and impurity transport. The imaging properties of these spherically or toroidally curved crystals provide both spectrally and spatially resolved X-ray data from the plasma using only one small spherically or toroidally curved crystal, thus eliminating the requirement for a large array of crystal spectrometers and the need to cross-calibrate the various crystals.

  11. X-ray survey of galaxy clusters in the SDSS Stripe 82 region

    Science.gov (United States)

    Durret, Florence; Takey, Ali

    2016-07-01

    We conducted a survey of galaxy clusters detected from XMM-Newton observations covering an area of 11.25 deg^2 in the Stripe 82 region of the Sloan Digital Sky Survey (SDSS). We found 94 X-ray cluster candidates from the third XMM-Newton serendipitous source catalogue (3XMM-DR5) and correlated this list with recently published X-ray and optically selected cluster catalogues to obtain optical confirmations and redshifts (between 0.05 and 1.19, with a median of 0.36) for 54 galaxy groups/clusters. Of these, 17 are newly X-ray discovered clusters and 45 systems with spectroscopic confirmations. Among the remaining candidates, 25 sources are distant cluster candidates (beyond a redshift of 0.6). We will present preliminary results on the X-ray and optical properties of these clusters: luminosities and temperatures of the X-ray gas, and optical properties of the galaxies (morphology, luminosity functions).

  12. X-ray Radio Correlation In Black Hole Sources

    CERN Document Server

    Rao, A R

    2006-01-01

    We examine the X-ray - radio correlation in Galactic black hole sources. We highlight some of the results which extend the flux-flux relations to sources with very high accretion rates. Some of the recent results indicate that the synchrotron process is unlikely to be the mechanism responsible for the X-ray emission, particularly at high accretion rates. We present a truncated accretion disk scenario and argue that accretion rate and accretion disk geometry ultimately act as a driver of the X-ray - radio correlation. We stress the importance of wide-band X-ray spectral measurements to understand the disk-jet connection and briefly outline some attempts made in the Indian context to build instruments for wide-band X-ray spectroscopy.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Meicun; Li, Zhiyuan, E-mail: lizy@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210046 (China)

    2016-03-10

    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{sup 36} erg s{sup −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{sup 35} erg s{sup −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.

  14. Constraining omega from X-ray properties of clusters of galaxies at high redshifts

    DEFF Research Database (Denmark)

    Sadat, R.; Blanchard, A.; Oukbir, J.

    1997-01-01

    Properties of high redshift clusters are a fundamental source of information for cosmology. It has been shown by Oukbir and Blanchard (1997) that the combined knowledge of the redshift distribution of X-ray clusters of galaxies and the luminosity-temperature correlation, L-X - T-X, provides a pow...

  15. X-ray bursters and the X-ray sources of the galactic bulge

    Science.gov (United States)

    Lewin, W. H. G.; Joss, P. C.

    1981-01-01

    An attempt is made to distill from observational and theoretical information on the galactic bulge X-ray sources in general, and on the X-ray burst sources in particular, those aspects which seem to have the greatest relevance to the understanding of these sources. Galactic bulge sources appear to be collapsed objects of roughly solar mass, in most cases neutron stars, which are accreting matter from low-mass stellar companions. Type I bursts seem to result from thermonuclear flashes in the surface layers of some of these neutron stars, while the type II bursts from the Rapid Burster are almost certainly due to an instability in the accretion flow onto a neutron star. It is concluded that the studies cited offer a new and powerful observational handle on the fundamental properties of neutron stars and of the interacting binary systems in which they are often contained.

  16. X-ray clusters of galaxies in conformal gravity

    CERN Document Server

    Diaferio, Antonaldo

    2008-01-01

    We run adiabatic N-body/hydrodynamical simulations of isolated self-gravitating gas clouds to test whether conformal gravity, an alternative theory to General Relativity, is able to explain the properties of X-ray galaxy clusters without resorting to dark matter. We show that the gas clouds rapidly reach equilibrium with a density profile which is well fit by a beta-model whose normalization and slope are in approximate agreement with observations. However, conformal gravity fails to yield the observed thermal properties of the gas cloud: (i) the mean temperature is at least an order of magnitude larger than observed; (ii) the temperature profiles increase with the square of the distance from the cluster center, in clear disagreement with real X-ray clusters. These results depend on a gravitational potential whose parameters reproduce the velocity rotation curves of spiral galaxies. However, this parametrization stands on an arbitrarily chosen conformal factor. It remains to be seen whether a different confor...

  17. Automated classification of Chandra X-ray sources

    Science.gov (United States)

    Brehm, Derek; Kargaltsev, O.; Rangelov, B.; Volkov, I.; Pavlov, G. G.

    2014-01-01

    With the advent of the latest generation X-ray telescopes there has been a major influx of data associated with the detection of hundreds of thousands X-ray sources. As one can rarely tell a source type from its X-ray properties alone, the full potential of the X-ray catalogs can only be unlocked by correlating multiwavelength (MW) properties via cross-identification with other surveys. However, one would spend an enormous amount of time classifying these objects by their physical nature if the classification was to be done on a source-by-source basis by humans. Therefore, we are using a supervised learning algorithm to classify sources detected by the Chandra X-ray Observatory. The classifications are based on a training dataset which currently includes about 7,000 X-ray sources of known nature (main sequence stars, Wolf-Rayet stars, young stars, active galactic nuclei, low mass X-ray binaries, high mass x-ray binaries, and neutron stars). For each source, the training dataset includes up to 24 multiwavelength properties. The efficiency and accuracy of the classification is verified by dividing the training dataset in two and performing cross-validation. The results are also inspected by plotting source properties in 2D slices of the parameter space. As an application of our automated procedure we classified unidentified sources in the supernova remnant (SNR) G352.7-0.1, in the field of HESS J1809-193, and in part of the Chandra Source Catalog 1.0. We present the results of the verification tests and the classification results. This research was partially supported by NASA/SAO grant AR3-14017X.

  18. Miniature X-ray Source for Planetary Exploration Instruments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the proposed work is to develop a rugged, low power, passively cooled X-Ray source that is compatible with miniaturized XRD systems. The XRD...

  19. X-ray Measurements of Black Hole X-ray Binary Source GRS 1915+105 and the Evolution of Hard X-ray Spectrum

    Indian Academy of Sciences (India)

    R. K. Manchanda

    2000-06-01

    We report the spectral measurement of GRS 1915+105 in the hard X-ray energy band of 20-140keV. The observations were made on March 30th, 1997 during a quiescent phase of the source. We discuss the mechanism of emission of hard X-ray photons and the evolution of the spectrum by comparing the data with earlier measurements and an axiomatic model for the X-ray source.

  20. X-Ray Morphological Analysis of the Planck ESZ Clusters

    Science.gov (United States)

    Lovisari, Lorenzo; Forman, William R.; Jones, Christine; Ettori, Stefano; Andrade-Santos, Felipe; Arnaud, Monique; Démoclès, Jessica; Pratt, Gabriel W.; Randall, Scott; Kraft, Ralph

    2017-09-01

    X-ray observations show that galaxy clusters have a very large range of morphologies. The most disturbed systems, which are good to study how clusters form and grow and to test physical models, may potentially complicate cosmological studies because the cluster mass determination becomes more challenging. Thus, we need to understand the cluster properties of our samples to reduce possible biases. This is complicated by the fact that different experiments may detect different cluster populations. For example, Sunyaev–Zeldovich (SZ) selected cluster samples have been found to include a greater fraction of disturbed systems than X-ray selected samples. In this paper we determine eight morphological parameters for the Planck Early Sunyaev–Zeldovich (ESZ) objects observed with XMM-Newton. We found that two parameters, concentration and centroid shift, are the best to distinguish between relaxed and disturbed systems. For each parameter we provide the values that allow selecting the most relaxed or most disturbed objects from a sample. We found that there is no mass dependence on the cluster dynamical state. By comparing our results with what was obtained with REXCESS clusters, we also confirm that the ESZ clusters indeed tend to be more disturbed, as found by previous studies.

  1. Velocity dispersions and X-ray temperatures of galaxy clusters

    CERN Document Server

    Girardi, M; Giuricin, G; Mardirossian, F; Mezzetti, M; Biviano, A

    1995-01-01

    Using a large and well-controlled sample of clusters of galaxies, we investigate the relation between cluster velocity dispersions and X-ray temperatures of intra-cluster gas. In order to obtain a reliable estimate of the total velocity dispersion of a cluster, independent of the level of anisotropies in galaxy orbits, we analyze the integrated velocity dispersion profiles over increasing distances from the cluster centers. Distortions in the velocity fields, the effect of close clusters, the presence of substructures, and the presence of a population of (spiral) galaxies not in virial equilibrium with the cluster potential are taken into account. Using our final sample of 37 clusters, for which a reliable estimate of the velocity dispersion could be obtained, we derive a relation between the velocity dispersions and the X-ray temperatures, with a scatter reduced by more than 30 % with respect to previous works. A chi square fit to the temperature-velocity dispersion relation does not exclude the hypothesis t...

  2. A giant radio halo in the low luminosity X-ray cluster Abell 523

    CERN Document Server

    Giovannini, G; Girardi, M; Govoni, F; Murgia, M; Vacca, V; Bagchi, J

    2011-01-01

    Radio halos are extended and diffuse non-thermal radio sources present at the cluster center, not obviously associated with any individual galaxy. A strong correlation has been found between the cluster X-ray luminosity and the halo radio power. We observe and analyze the diffuse radio emission present in the complex merging structure Abell 523, classified as a low luminosity X-ray cluster, to discuss its properties in the context of the halo total radio power versus X-ray luminosity correlation. We reduced VLA archive observations at 1.4 GHz to derive a deep radio image of the diffuse emission, and compared radio, optical, and X-ray data. Low-resolution VLA images detect a giant radio halo associated with a complex merging region. The properties of this new halo agree with those of radio halos in general discussed in the literature, but its radio power is about a factor of ten higher than expected on the basis of the cluster X-ray luminosity. Our study of this giant radio source demonstrates that radio halos...

  3. X-ray archaeology in the Coma cluster

    Science.gov (United States)

    White, Simon D. M.; Briel, Ulrich G.; Henry, J. P.

    1993-01-01

    We present images of X-ray emission from hot gas within the Coma cluster of galaxies. These maps, made with the ROSAT satellite, have much higher SNR than any previous X-ray image of a galaxy cluster, and allow cluster structure to be analyzed in unprecedented detail. They show greater structural irregularity than might have been anticipated from earlier observations of Coma. Emission is detected from a number of bright cluster galaxies in addition to the two known previously. In four cases, there is evidence that these galaxies lie at the center of an extended subconcentration within the cluster, possibly the remnant of their associated groups. For at least two galaxies, the images show direct evidence for ongoing disruption of their gaseous atmosphere. The luminosity associated with these galaxies is comparable to that detected around similar ellipticals in much poorer environments. Emission is easily detected to the limit of our field, about 1 deg from the cluster center, and appears to become more regular at large radii. The data show clearly that this archetype of a rich and regular galaxy cluster was, in fact, formed by the merging of several distinct subunits which are not yet fully destroyed.

  4. X-ray archaeology in the Coma cluster

    Science.gov (United States)

    White, Simon D. M.; Briel, Ulrich G.; Henry, J. P.

    1993-01-01

    We present images of X-ray emission from hot gas within the Coma cluster of galaxies. These maps, made with the ROSAT satellite, have much higher SNR than any previous X-ray image of a galaxy cluster, and allow cluster structure to be analyzed in unprecedented detail. They show greater structural irregularity than might have been anticipated from earlier observations of Coma. Emission is detected from a number of bright cluster galaxies in addition to the two known previously. In four cases, there is evidence that these galaxies lie at the center of an extended subconcentration within the cluster, possibly the remnant of their associated groups. For at least two galaxies, the images show direct evidence for ongoing disruption of their gaseous atmosphere. The luminosity associated with these galaxies is comparable to that detected around similar ellipticals in much poorer environments. Emission is easily detected to the limit of our field, about 1 deg from the cluster center, and appears to become more regular at large radii. The data show clearly that this archetype of a rich and regular galaxy cluster was, in fact, formed by the merging of several distinct subunits which are not yet fully destroyed.

  5. X-ray groups and clusters of galaxies in the Subaru-XMM Deep Field

    CERN Document Server

    Finoguenov, A; Tanaka, M; Simpson, C; Cirasuolo, M; Dunlop, J S; Peacock, J A; Farrah, D; Akiyama, M; Ueda, Y; Smolcic, V; Stewart, G; Rawlings, S; van Breukelen, C; Almaini, O; Clewley, L; Bonfield, D G; Jarvis, M J; Barr, J M; Foucaud, S; McLure, R J; Sekiguchi, K; Egami, E

    2009-01-01

    We present the results of a search for galaxy clusters in Subaru-XMM Deep Field. We reach a depth for a total cluster flux in the 0.5-2 keV band of 2x10^{-15} ergs cm^{-2} s^{-1} over one of the widest XMM-Newton contiguous raster surveys, covering an area of 1.3 square degrees. Cluster candidates are identified through a wavelet detection of extended X-ray emission. The red sequence technique allows us to identify 57 cluster candidates. We report on the progress with the cluster spectroscopic follow-up and derive their properties based on the X-ray luminosity and cluster scaling relations. In addition, 3 sources are identified as X-ray counterparts of radio lobes, and in 3 further sources, X-ray counterpart of radio lobes provides a significant fraction of the total flux of the source. In the area covered by NIR data, our identification success rate achieves 86%. We detect a number of radio galaxies within our groups and for a luminosity-limited sample of radio galaxies we compute halo occupation statistics ...

  6. First X-ray observations of Low-Power Compact Steep Spectrum Sources

    CERN Document Server

    Kunert-Bajraszewska, M; Siemiginowska, A; Guainazzi, M

    2013-01-01

    We report first X-ray Chandra observations of a sample of seven low luminosity compact (LLC) sources. They belong to a class of young compact steep spectrum (CSS) radio sources. Four of them have been detected, the other three have upper limit estimations for X-ray flux, one CSS galaxy is associated with an X-ray cluster. We have used the new observations together with the observational data for known strong CSS and gigahertz-peaked spectrum (GPS) objects and large scale FRIs and FRIIs to study the relation between morphology, X-ray properties and excitation modes in radio-loud AGNs. We found that: (1) The low power objects fit well to the already established X-ray - radio luminosity correlation for AGNs and occupy the space among, weaker in the X-rays, FRI objects. (2) The high excitation galaxies (HEG) and low excitation galaxies (LEG) occupy distinct locus in the radio/X-ray luminosity plane, notwithstanding their evolutionary stage. This is in agreement with the postulated different origin of the X-ray em...

  7. VizieR Online Data Catalog: X-ray cavities from isolated gal. to clusters (Shin+, 2016)

    Science.gov (United States)

    Shin, J.; Woo, J.-H.; Mulchaey, J. S.

    2017-01-01

    To search X-ray cavities, we used available Chandra X-ray images, which provide high spatial resolution (PSF FWHM ~0.5" at the aim point). We considered sources in the Chandra archive in one of three categories, namely, "normal galaxies", "cluster of galaxies", and "active galaxies and quasar". For our cavity study, we used a final sample of 133 targets based on a consistent analysis of X-ray photon counts. (2 data files).

  8. RADIO AND X-RAY SHOCKS IN CLUSTERS OF GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sungwook E. [School of Physics, Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of); Kang, Hyesung [Department of Earth Sciences, Pusan National University, Busan 609-735 (Korea, Republic of); Ryu, Dongsu, E-mail: swhong@kias.re.kr, E-mail: hskang@pusan.ac.kr, E-mail: ryu@sirius.unist.ac.kr [Department of Physics, UNIST, Ulsan 689-798 (Korea, Republic of)

    2015-10-10

    Radio relics detected in the outskirts of galaxy clusters are thought to trace radio-emitting relativistic electrons accelerated at cosmological shocks. In this study, using the cosmological hydrodynamic simulation data for the large-scale structure formation and adopting a diffusive shock acceleration (DSA) model for the production of cosmic-ray (CR) electrons, we construct mock radio and X-ray maps of simulated galaxy clusters that are projected in the sky plane. Various properties of shocks and radio relics, including the shock Mach number, radio spectral index, and luminosity, are extracted from the synthetic maps and compared with observations. A substantial fraction of radio and X-ray shocks identified in these maps involve multiple shock surfaces along lines of sight (LOSs), and the morphology of shock distributions in the maps depends on the projection direction. Among multiple shocks in a given LOS, radio observations tend to pick up stronger shocks with flatter radio spectra, while X-ray observations preferentially select weaker shocks with larger kinetic energy flux. As a result, in some cases the shock Mach numbers and locations derived from radio and X-ray observations could differ from each other. We also find that the distributions of the spectral index and radio power of the synthetic radio relics are somewhat inconsistent with those of observed real relics; a bit more radio relics have been observed closer to the cluster core and with steeper spectral indices. We suggest that the inconsistency could be explained if very weak shocks with M{sub s} ≲ 2 accelerate CR electrons more efficiently, compared with the DSA model adopted here.

  9. Chandra Multiwavelength Project X-ray Point Source Catalog

    CERN Document Server

    Kim, M; Wilkes, B J; Green, P J; Kim, E; Anderson, C S; Barkhouse, W A; Evans, N R; Ivezic, Z; Karovska, M; Kashyap, V L; Lee, M G; Maksym, P; Mossman, A E; Silverman, J D; Tananbaum, H D; Kim, Minsun; Kim, Dong-Woo; Wilkes, Belinda J.; Green, Paul J.; Kim, Eunhyeuk; Anderson, Craig S.; Barkhouse, Wayne A.; Evans, Nancy R.; Ivezic, Zeljko; Karovska, Margarita; Kashyap, Vinay L.; Lee, Myung Gyoon; Maksym, Peter; Mossman, Amy E.; Silverman, John D.; Tananbaum, Harvey D.

    2006-01-01

    We present the Chandra Multiwavelength Project (ChaMP) X-ray point source catalog with ~6,800 X-ray sources detected in 149 Chandra observations covering \\~10 deg^2. The full ChaMP catalog sample is seven times larger than the initial published ChaMP catalog. The exposure time of the fields in our sample ranges from 0.9 to 124 ksec, corresponding to a deepest X-ray flux limit of f_{0.5-8.0} = 9 x 10^{-16} erg/cm2/sec. The ChaMP X-ray data have been uniformly reduced and analyzed with ChaMP-specific pipelines, and then carefully validated by visual inspection. The ChaMP catalog includes X-ray photometric data in 8 different energy bands as well as X-ray spectral hardness ratios and colors. To best utilize the ChaMP catalog, we also present the source reliability, detection probability and positional uncertainty. To quantitatively assess those parameters, we performed extensive simulations. In particular, we present a set of empirical equations: the flux limit as a function of effective exposure time, and the p...

  10. HIGH-Z X-RAY AGN CLUSTERING & COSMOLOGICAL INFERENCE

    Directory of Open Access Journals (Sweden)

    M. Plionis

    2009-01-01

    Full Text Available We study the angular clustering of X-ray selected active galactic nuclei (AGN in di erent ux-limited sub- samples of the Chandra Deep Field North (CDF-N and South (CDF-S surveys. We nd a strong dependence of the clustering strength on the sub-sample ux-limit, a fact which explains most of the disparate clustering results of di erent XMM and Chandra surveys. At high ux-limits the clustering length increases considerably; for example, at fx;limit 1015 erg s-1 cm-2, we obtain r0 ' 17 5 and 18 3 h-1 Mpc, for the CDF-N and CDF-S, respectively. The ux-limit dependence translates into a luminosity dependent X-ray AGN clustering. Applying the standard formalism relating the theoretical CDM model clustering to the data in a at cosmology (for w =-1 and h = 0:72, we nd: m ' 0:28 0:03 and 8 ' 0:75 0:03; while utilizing also the SN Ia Hubble relation (for 8 = 0:75 and h = 0:72, we nd: m ' 0:26 0:04 and w = 0:9 0:1

  11. Results from the Daresbury Compton backscattering X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Laundy, D. [STFC Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD (United Kingdom); Priebe, G. [Max Born Institute, Max-Born-Strasse 2A, 12489 Berlin, DE (Germany); Jamison, S.P. [STFC Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD (United Kingdom); Graham, D.M. [The Photon Science Institute, The University of Manchester, Manchester M13 9PL (United Kingdom); Phillips, P.J. [STFC Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX (United Kingdom); Smith, S.L.; Saveliev, Y. [STFC Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD (United Kingdom); Vassilev, S. [The University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Seddon, E.A., E-mail: elaine.seddon@stfc.ac.uk [The Photon Science Institute, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2012-10-11

    The Daresbury Compton Backscattering X-ray Source uses a high power Ti Sapphire laser interacting in head on geometry with electron bunches in the ALICE energy recovery linear accelerator. X-ray photons with peak energy of 21 keV were generated with the accelerator operating at an energy of 29.6 MeV. The spatial profile of the X-rays emitted near the electron beam axis was measured. The characteristics of the X-ray yield measured as a function of relative timing between the laser pulse and the interacting electron bunch was found to be consistent with the modelled intensity behaviour using measured electron and laser beam parameters.

  12. Advanced analysis tool for X-ray photoelectron spectroscopy profiling: Cleaning of perovskite SrTiO{sub 3} oxide surface using argon cluster ion source

    Energy Technology Data Exchange (ETDEWEB)

    Aureau, D., E-mail: damien.aureau@uvsq.fr [Institut Lavoisier de Versailles, (UMR 8180) Université de Versailles-Saint-Quentin-en-Yvelines–CNRS, 45 Av. des États-Unis, 78035 Versailles (France); Ridier, K. [Institut Lavoisier de Versailles, (UMR 8180) Université de Versailles-Saint-Quentin-en-Yvelines–CNRS, 45 Av. des États-Unis, 78035 Versailles (France); Groupe d' Étude de la Matière Condensée (UMR 8635) Université de Versailles Saint-Quentin-en-Yvelines–CNRS, 45 Av. des États-Unis, 78035 Versailles (France); Bérini, B.; Dumont, Y.; Keller, N. [Groupe d' Étude de la Matière Condensée (UMR 8635) Université de Versailles Saint-Quentin-en-Yvelines–CNRS, 45 Av. des États-Unis, 78035 Versailles (France); Vigneron, J.; Bouttemy, M.; Etcheberry, A. [Institut Lavoisier de Versailles, (UMR 8180) Université de Versailles-Saint-Quentin-en-Yvelines–CNRS, 45 Av. des États-Unis, 78035 Versailles (France); Fouchet, A. [Groupe d' Étude de la Matière Condensée (UMR 8635) Université de Versailles Saint-Quentin-en-Yvelines–CNRS, 45 Av. des États-Unis, 78035 Versailles (France)

    2016-02-29

    This article shows the comparison between three different ionic bombardments during X-ray photoelectron spectroscopy (XPS) studies of single crystalline SrTiO{sub 3} (STO) substrates. The abrasion using a “cluster argon ion source” is compared with the standard “monoatomic Ar”. The influence of the energy of the monoatomic ions used is clearly demonstrated. While the chemically adsorbed species on the STO surface are removed, such bombardment strongly modifies the surface. A reduction of part of the titanium atoms and the appearance of a different chemical environment for surface strontium atoms are observed. Implantation of argon ions is also detected. Cluster ion etching is used on oxide surface and, in this case only, due to a much lower kinetic energy per atom compared to monoatomic ions, the possibility to remove surface contaminants at the surface without modification of the XP spectra is clearly demonstrated, ensuring that the stoichiometry of the surface is preserved. Such result is crucial for everybody working with oxide surfaces to obtain a non-modified XPS analysis. The progressive effect of this powerful tool allows the monitoring of the removal of surface contamination in the first steps of the bombardment which was not achievable with usual guns. - Highlights: • The effects of three argon etchings are studied as a function of time on SrTiO3 oxide. • A method for obtaining non-modified chemical analysis of oxides is presented. • The soft removal of adsorbed species thanks to argon cluster is demonstrated. • The damages induced on SrTiO3 surface by ionic bombardment are shown. • The influence of the kinetic energy of incoming Ar atoms is examined.

  13. Studies of Supersoft X-ray Sources (SSS) and Quasisoft X-ray Sources (QSS) in the Milky Way and Magellanic Clouds

    Science.gov (United States)

    Pun, Chun-Shing J.; Li, K.; Kong, A. K. H.; DiStefano, R.

    2010-03-01

    Quasisoft X-ray sources (QSSs) are luminous (L > 1036 erg s-1, kT between 120eV and 350eV) X-ray sources emitting few or no photons at energy above 2 keV yet clearly emitting at above 1.1 keV. While their spectra are harder than luminous supersoft X-ray sources (SSSs), which have characteristic temperatures of tens of eV, QSSs are significantly softer than most canonical X-ray sources. They have been identified in elliptical galaxies, spiral galaxies (in both spiral arms and halos), and globular clusters. We report here on the progress of a comprehensive and systematic search of SSSs and QSSs in the Milky Way and in the Magellanic Clouds using archival X-ray data. Our focus is to conduct an optimized search to identify all candidates in order to differentiate between the different natures of SSSs and QSSs. The candidates collected would be checked for counterparts in other wavelengths, which could possibly help us to determine the fundamental nature of these sources, including the properties, if present, of the accretors and the accretion disks. This work is supported by a Hong Kong SAR Research Grants Council General Research Fund and by a NASA ADP grant.

  14. Development of a new X-ray source using backscattered X-ray with the use of a cold cathode

    Science.gov (United States)

    Tanizawa, Keisuke; Sekiya, Tetsuo; Ohshio, Shigeo; Akasaka, Hiroki; Saitoh, Hidetoshi

    2011-02-01

    The development of an intense X-ray source using backscattered X-ray produced using an advanced electrode configuration is described. The electrodes were composed of field emitters deposited on a wire mounted on a perforated plate as the cathode and a copper plate as the anode. Electrons from these emitters collided with the copper plate and X-ray was generated at collision points. The backscattered X-ray in the direction normal to the electron trajectory through a hole in the anode escaped from the vacuum chamber through a beryllium window. Continuous and characteristic X-rays were detected at an applied voltage lower than that of a conventional X-ray source from 3.0 to 9.4 kV, respectively. Moreover, the X-ray dosage measured with a survey meter reached 0.95 mSv/h at 5.0 kV of applied voltage. The transmission images of three types of material used as an X-ray source for the X-ray imaging system indicate three advantages; low power consumption, focal point controllable by adjusting applied voltage, and photographable motion picture of X-ray transmission.

  15. Optical Counterparts of Ultra Luminous X-ray Sources

    CERN Document Server

    Gutíerrez, C M

    2006-01-01

    We present optical identification and characterization of counterparts of four objects previously catalogued as ultra-luminous X-ray sources. The objects were selected from the Colbert & Ptak (2002) catalogue. The optical counterparts are identified as point-like objects with magnitudes in the range \\~17-19. The optical spectra of three of the sources (IXO 32, 37 and 40) show the presence of emission lines typical of quasars. The position of these lines allows a precise estimation of their redshifts (2.769, 0.567 and 0.789 for IXO 32, 37 and 40 respectively). The fourth X-ray source, IXO35, is associated with a red object that has a spectrum typical of an M star in our Galaxy. These identifications are useful for building clean samples of ULX sources, selecting suitable targets for future observations and performing statistical studies on the different populations of X-ray sources.

  16. Optimized Volumetric Scanning for X-Ray Array Sources

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, S K; Foudray, A M; Wang, A; Kallman, J S; Martz, H

    2009-09-29

    Non-destructive evaluation (NDE) is the science and technology of determining non-invasively the internal structure of manufactured parts, objects, and materials. NDE application areas include medicine, industrial manufacturing, military, homeland security, and airport luggage screening. X-ray measurement systems are most widely used because of their ability to image through a wide range of material densities (from human tissue in medical applications to the dense materials of weapon components). Traditional x-ray systems involve a single source and detector system that rotate and/or translate about the object under evaluation. At each angular location, the source projects x-rays through the object. The rays undergo attenuation proportional to the density of the object's constitutive material. The detector records a measure of the attenuation. Mathematical algorithms are used to invert the forward attenuated ray projection process to form images of the object. This is known as computed tomography (CT). In recent years, the single-source x-ray NDE systems have been generalized to arrays of x-ray sources. Array sources permit multiple views of the object with fewer rotations and translations of the source/detector system. The spatially diverse nature of x-ray array sources has the potential of reducing data collection time, reducing imaging artifacts, and increasing the resolution of the resultant images. Most of the existing CT algorithms were not derived from array source models with a spatially diverse set of viewing perspectives. Single-source x-ray CT data collection, processing, and imaging methods and algorithms are not applicable when the source location is expanded from one dimension (a rotating and/or translating point source) to two (a rotating and/or translating array). They must be reformulated. The goal of this project is to determine the applicability of x-ray array sources to problems of interest to LLNL and its customers. It is believed array

  17. X-ray selected galaxy clusters in the Pan-STARRS Medium-Deep Survey

    CERN Document Server

    Ebeling, H; Burgett, W S; Hodapp, K W; Huber, M E; Kaiser, N; Price, P A; Tonry, J L

    2013-01-01

    [abridged] We present the results of a pilot study for the extended MACS survey (eMACS), a comprehensive search for distant, X-ray luminous galaxy clusters at z>0.5. Our pilot study applies the eMACS concept to the 71 deg^2 area extended by the ten fields of the Pan-STARRS1 (PS1) Medium Deep Survey (MDS). Candidate clusters are identified by visual inspection of PS1 images in the g,r, i, and z bands in a 5x5 arcmin^2 region around X-ray sources detected in the ROSAT All-Sky Survey (RASS). To test and optimize the eMACS X-ray selection criteria, our pilot study uses the largest possible RASS database, i.e., all RASS sources listed in the Bright and Faint Source Catalogs (BSC and FSC) that fall within the MDS footprint. Scrutiny of PS1/MDS images for 41 BSC and 200 FSC sources combined with dedicated spectroscopic follow-up observations results in a sample of 11 clusters with estimated or spectroscopic redshifts of z>0.3. X-ray follow-up observations will be crucial in order to establish robust cluster luminosi...

  18. X-ray Optics for BES Light Source Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Dennis [Argonne National Lab. (ANL), Argonne, IL (United States); Padmore, Howard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lessner, Eliane [Dept. of Energy (DOE), Washington DC (United States). Office of Science

    2013-03-27

    Each new generation of synchrotron radiation sources has delivered an increase in average brightness 2 to 3 orders of magnitude over the previous generation. The next evolution toward diffraction-limited storage rings will deliver another 3 orders of magnitude increase. For ultrafast experiments, free electron lasers (FELs) deliver 10 orders of magnitude higher peak brightness than storage rings. Our ability to utilize these ultrabright sources, however, is limited by our ability to focus, monochromate, and manipulate these beams with X-ray optics. X-ray optics technology unfortunately lags behind source technology and limits our ability to maximally utilize even today’s X-ray sources. With ever more powerful X-ray sources on the horizon, a new generation of X-ray optics must be developed that will allow us to fully utilize these beams of unprecedented brightness. The increasing brightness of X-ray sources will enable a new generation of measurements that could have revolutionary impact across a broad area of science, if optical systems necessary for transporting and analyzing X-rays can be perfected. The high coherent flux will facilitate new science utilizing techniques in imaging, dynamics, and ultrahigh-resolution spectroscopy. For example, zone-plate-based hard X-ray microscopes are presently used to look deeply into materials, but today’s resolution and contrast are restricted by limitations of the current lithography used to manufacture nanodiffractive optics. The large penetration length, combined in principle with very high spatial resolution, is an ideal probe of hierarchically ordered mesoscale materials, if zone-plate focusing systems can be improved. Resonant inelastic X-ray scattering (RIXS) probes a wide range of excitations in materials, from charge-transfer processes to the very soft excitations that cause the collective phenomena in correlated electronic systems. However, although RIXS can probe high-energy excitations, the most exciting and

  19. X-ray Optics for BES Light Source Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Dennis [Argonne National Lab. (ANL), Argonne, IL (United States); Padmore, Howard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lessner, Eliane [Dept. of Energy (DOE), Washington DC (United States). Office of Science

    2013-03-27

    Each new generation of synchrotron radiation sources has delivered an increase in average brightness 2 to 3 orders of magnitude over the previous generation. The next evolution toward diffraction-limited storage rings will deliver another 3 orders of magnitude increase. For ultrafast experiments, free electron lasers (FELs) deliver 10 orders of magnitude higher peak brightness than storage rings. Our ability to utilize these ultrabright sources, however, is limited by our ability to focus, monochromate, and manipulate these beams with X-ray optics. X-ray optics technology unfortunately lags behind source technology and limits our ability to maximally utilize even today’s X-ray sources. With ever more powerful X-ray sources on the horizon, a new generation of X-ray optics must be developed that will allow us to fully utilize these beams of unprecedented brightness. The increasing brightness of X-ray sources will enable a new generation of measurements that could have revolutionary impact across a broad area of science, if optical systems necessary for transporting and analyzing X-rays can be perfected. The high coherent flux will facilitate new science utilizing techniques in imaging, dynamics, and ultrahigh-resolution spectroscopy. For example, zone-plate-based hard X-ray microscopes are presently used to look deeply into materials, but today’s resolution and contrast are restricted by limitations of the current lithography used to manufacture nanodiffractive optics. The large penetration length, combined in principle with very high spatial resolution, is an ideal probe of hierarchically ordered mesoscale materials, if zone-plate focusing systems can be improved. Resonant inelastic X-ray scattering (RIXS) probes a wide range of excitations in materials, from charge-transfer processes to the very soft excitations that cause the collective phenomena in correlated electronic systems. However, although RIXS can probe high-energy excitations, the most exciting and

  20. Complex X-ray morphology of Abell 3128 : a distant cluster behind a disturbed cluster

    NARCIS (Netherlands)

    Werner, N.; Churazov, E.; Finoguenov, A.; Markevitch, M.; Burenin, R.; Kaastra, J.S.; Böhringer, H.

    2007-01-01

    We present here the results of a detailed study of the X-ray properties of the cluster of galaxies Abell 3128 (z = 0.06), based on the analysis of deep (100 ks) XMM-Newton data. The most obvious feature of the X-ray morphology of A3128 is the presence of two X-ray peaks separated by ∼12'. By detecti

  1. Evolution of the cluster X-ray luminosity function

    DEFF Research Database (Denmark)

    Mullis, C.R.; Vikhlinin, A.; Henry, J.P.

    2004-01-01

    We report measurements of the cluster X-ray luminosity function out to z = 0.8 based on the final sample of 201 galaxy systems from the 160 Square Degree ROSAT Cluster Survey. There is little evidence for any measurable change in cluster abundance out to z similar to 0.6 at luminosities of less...... than a few times 10(44) h(50)(-2) ergs s(-1) (0.5 - 2.0 keV). However, for 0.6 cluster deficit using integrated number counts...... and a maximum likelihood analysis of the observed luminosity-redshift distribution fit with a model luminosity function. The negative evolution signal is more than 3 sigma regardless of the adopted local luminosity function or cosmological framework. Our results and those from several other surveys...

  2. The ROSAT deep survey; 5, X-rays Sources and Optical Identifications in the Marano Field

    CERN Document Server

    Zamorani, G; Hasinger, G; Burg, R; Giacconi, R; Schmidt, M; Trümper, J E; Ciliegi, P; Gruppioni, C; Marano, B

    1999-01-01

    We present the X-ray data and the optical identifications for a deep ROSAT PSPC observation in the "Marano field". In the inner region of the ROSAT field (15' radius) we detected 50 X-ray sources with Sx >= 3.7x10^(-15) erg/cm^2/s. When corrected for the different sensitivity over the field, the estimated observed surface density at Sx >= 4x10^(-15) erg/cm^2/s is 272+/-40 sources/sq.deg. Four X-ray sources, corresponding to 8% of the total sample, have been detected in radio images with a flux limit of about 0.2 mJy. Careful statistical analysis of multicolour CCD data in the error boxes of the 50 X-ray sources has led to the identification of 42 sources, corresponding to 84% of the X-ray sample. These 42 reliable identifications are 33 AGNs (including two radio galaxies and one BL Lac candidate; 79% of the identified sources), 2 galaxies, 3 groups or clusters of galaxies and 4 stars. We also show that it is likely that a few of the 8 unidentified sources are such because the derived X-ray positions may be of...

  3. Development of a flat-panel X-ray source

    Science.gov (United States)

    Grant, Edwin Joseph

    A novel flat-panel transmission type X-ray source was developed for both medical and industrial use. Depending on the geometry of the given situation, the flat-panel X-ray source could be used in tomography, radiography or tomosynthesis. Furthermore, the unit could be used as a portable X-ray scanner or an integral part of an existing detection system. The design incorporates a field emission cathode made of ultra-nanocrystalline diamonds (UNCD) doped with nitrogen. These field emitters show good electron output at low power and can be deposited over large areas as is the case with carbon nanotube "forest" (CNT) cathodes. This work presents the first generation of the UNCD based FEA prototype which was manufactured at the Center of Nanoscale Material, within Argonne National Laboratory, with standard microfabrication techniques. The prototype is a 3 x 3 pixel field emission array (FEA), with a pixel size of 225 mum by 225 mum and a pitch of 500 mum. The fabricated cathode was developed using a microfabrication process which allows for individual electrically addressable UNCD gated arrays on-chip which demonstrated monolithic integration of the electron extraction grid. The transmission target consists of tungsten for X-ray generation, which is sputtered directly upon a thin aluminum sheet as an X-ray filter. A low voltage power supply allows for electron extraction between the cathode and the grid; while a high voltage power supply accelerates the electrons towards the anode. A low energy X-ray high purity germanium detector (HPGe) is mounted outside of the vacuum chamber for X-ray detection and measurement.

  4. A JEM-X catalog of X-ray sources

    DEFF Research Database (Denmark)

    Westergaard, Niels Jørgen Stenfeldt; Chenevez, Jerome; Lund, Niels;

    2007-01-01

    The JEM-X catalog of X-ray sources presented here is based on detections in individual science windows with a sensitivity limit of about 10 mCrab (5-15 keV). It contains 127 sources and only those that can be identified from the existing reference catalog. The input data are taken from the, up...

  5. X-ray Counterparts of Infrared Faint Radio Sources

    Science.gov (United States)

    Schartel, Norbert

    2011-10-01

    Infrared Faint Radio Sources (IFRS) are radio sources with extremely faint or even absent infrared emission in deep Spitzer Surveys. Models of their spectral energy distributions, the ratios of radio to infrared flux densities and their steep radio spectra strongly suggest that IFRS are AGN at high redshifts (2IFRS, but if confirmed, the increased AGN numbers at these redshifts will account for the unresolved part of the X-ray background. The identification of X-ray counterparts of IFRS is considered to be the smoking gun for this hypothesis. We propose to observe 8 IFRS using 30ks pointed observations. X-ray detections of IFRS with different ratios of radio-to-infrared fluxes, will constrain the class-specific SED.

  6. Movable anode x-ray source with enhanced anode cooling

    Science.gov (United States)

    Bird, C.R.; Rockett, P.D.

    1987-08-04

    An x-ray source is disclosed having a cathode and a disc-shaped anode with a peripheral surface at constant radius from the anode axis opposed to the cathode. The anode has stub axle sections rotatably carried in heat conducting bearing plates which are mounted by thermoelectric coolers to bellows which normally bias the bearing plates to a retracted position spaced from opposing anode side faces. The bellows cooperate with the x-ray source mounting structure for forming closed passages for heat transport fluid. Flow of such fluid under pressure expands the bellows and brings the bearing plates into heat conducting contact with the anode side faces. A worm gear is mounted on a shaft and engages serrations in the anode periphery for rotating the anode when flow of coolant is terminated between x-ray emission events. 5 figs.

  7. A Radio Survey of Seven Southern X-ray Luminous Clusters of Galaxies

    CERN Document Server

    Slee, O B; McIntyre, V J; Tsarevsky, G S

    2008-01-01

    The Australia Telescope Compact Array (ATCA) has been used at 1.38 and 2.38 GHz to survey seven southern Abell clusters of galaxies with high X-ray luminosities: A2746, A2837, A3126, A3216, A3230, A3827 and A3836. The clusters have also been surveyed at 0.843 GHz with the Molonglo Observatory Synthesis Telescope (MOST). We have listed a complete 1.38-GHz sample of 149 radio sources within the Abell circles centred on their X-ray centroids. We compare their identification fractions, emitted 1.38-GHz and optical powers, radio spectral indices and radial variation in projected source density with those of the radio-selected samples of Slee et al. (1998). We compare our fractional radio luminosity function with that of the radio-selected samples of Ledlow and Owen (1996) and Slee et al. (1998). Three significant differences are noted between X-ray and radio-selected samples of clusters; (1) the X-ray sample has an excess of flat-spectrum radio sources; (2) the fractional radio luminosity function for the FR I sou...

  8. Hard X-ray-induced optical luminescence via biomolecule-directed metal clusters.

    Science.gov (United States)

    Osakada, Yasuko; Pratx, Guillem; Sun, Conroy; Sakamoto, Masanori; Ahmad, Moiz; Volotskova, Olga; Ong, Qunxiang; Teranishi, Toshiharu; Harada, Yoshie; Xing, Lei; Cui, Bianxiao

    2014-04-07

    Here, we demonstrate that biomolecule-directed metal clusters are applicable in the study of hard X-ray excited optical luminescence, promising a new direction in the development of novel X-ray-activated imaging probes.

  9. Understanding X-ray reflection emissivity profiles in AGN: Locating the X-ray source

    CERN Document Server

    Wilkins, D R

    2012-01-01

    The illumination pattern (or emissivity profile) of the accretion disc due to the reflection of X-rays in AGN can be understood in terms of relativistic effects on the rays propagating from a source in a corona surrounding the central black hole, both on their trajectories and on the accretion disc itself. Theoretical emissivity profiles due to isotropic point sources as well as simple extended geometries are computed in general relativistic ray tracing simulations performed on graphics processing units (GPUs). Such simulations assuming only general relativity naturally explain the accretion disc emissivity profiles determined from relativistically broadened emission lines which fall off steeply (with power law indices of between 6 and 8) over the inner regions of the disc, then flattening off to almost a constant before tending to a constant power law of index 3 over the outer disc. Simulations for a variety of source locations, extents and geometries show how the emissivity profiles depend on these properti...

  10. A multipurpose tunable source of monochromatic X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Chesta, M.A.; Plivelic, T.S.; Mainardi, R.T. E-mail: mainardi@mail.famaf.unc.edu.ar

    2002-02-01

    The emission of characteristic X-rays from any chemical element induced by beta particles of high energy (10{sup 5}-10{sup 6} eV) is much higher than photon excitation, with the possible exception of selective excitation. This work describes the properties of a variable energy X-ray generator that uses {sup 90}Sr as a source of beta particles and a multitarget array in a transparent source geometry. This compact device provides, through suitable selection of the target material, over 30 monoenergetic lines spread uniformly in the energy range of between 6 and 100 keV. The X-ray photon flux thus generated has an intensity of between 10{sup 2}-10{sup 3} s{sup -1} sr{sup -1} per MBq of the beta source activity. With this single beta source, the X-ray yield is higher as compared with generators using {sup 241}Am or other X- or gamma-ray sources with the same activity, and the line's intensity changes by less than a factor of three over the whole energy range.

  11. X-RAY SOURCES IN THE DWARF SPHEROIDAL GALAXY DRACO

    Energy Technology Data Exchange (ETDEWEB)

    Sonbas, E. [University of Adiyaman, Department of Physics, 02040 Adiyaman (Turkey); Rangelov, B.; Kargaltsev, O.; Dhuga, K. S.; Hare, J.; Volkov, I., E-mail: edasonbas@yahoo.com [Department of Physics, The George Washington University, Washington, DC 20052 (United States)

    2016-04-10

    We present the spectral analysis of an 87 ks XMM-Newton observation of Draco, a nearby dwarf spheroidal galaxy. Of the approximately 35 robust X-ray source detections, we focus our attention on the brightest of these sources, for which we report X-ray and multiwavelength parameters. While most of the sources exhibit properties consistent with active galactic nuclei, few of them possess the characteristics of low-mass X-ray binaries (LMXBs) and cataclysmic variable (CVs). Our analysis places constraints on the population of X-ray sources with L{sub X} > 3 × 10{sup 33} erg s{sup −1} in Draco, suggesting that there are no actively accreting black hole and neutron star binaries. However, we find four sources that could be quiescent state LMXBs/CVs associated with Draco. We also place constraints on the central black hole luminosity and on a dark matter decay signal around 3.5 keV.

  12. X-ray survey of clusters of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Kowalski, M.P.

    1982-01-01

    This thesis is an investigation of the x-ray properties of clusters of galaxies. The data were taken by the A-1 experiment aboard the HEAO 1 satellite in the 0.5 to 20 keV energy band. All clusters in both the Abell catalog and Duus and Newell southern cluster catalog were examined. An error box or an explicit upper limit was obtained for every cluster. The appendices present extensive lists of the survey results. A complete discussion of the reduction and analysis procedure is given. Supporting optical data (morphological classifications and redshifts) were obtained from the literature and included in the appendices. Each cluster in both catalogs has an estimated or measured redshift. Redshift measurements of cluster galaxies were obtained at Kitt Peak National Observatory. A complete description of these observations with the 2.1 meter telescope is given. A statistical subset of the Southern catalog was defined, making it possible to combine the Abell and Southern catalogs, and thereby take advantage of the large data base afforded by the combined catalogs. Between 10/sup 42/ /sup 5/ and 10/sup 45/ /sup 5/ ergs s/sup -1/ the luminosity function for all clusters and groups of galaxies is well represented. The integrated volume emissivity is 18.66 x 10/sup 37/ ergs s/sup -1/ Mpc/sup -3/.

  13. The ROSAT-ESO Flux Limited X-ray Galaxy Cluster Survey (REFLEX II) I. Newly identified X-ray luminous clusters at z>=0.2

    CERN Document Server

    Chon, Gayoung

    2011-01-01

    We report 19 intermediate redshift clusters newly detected in the ROSAT All-Sky survey that are spectroscopically confirmed. They form a part of 911 objects in the REFLEX II cluster catalogue with a limiting flux of 1.8\\times10^12 erg/s/cm2 in the 0.1-2.4 keV ROSAT band at redshift z >= 0.2. In addition we report three clusters from the REFLEX III supplementary catalogue, which contains objects below the REFLEX II flux limit but satisfies the redshift constraint above. These clusters are spectroscopically followed-up by our ESO NTT-EFOSC2 campaigns for the redshift measurement. We describe our observing and data reduction methods. We show how X-ray properties such as spectral hardness ratio and source extent can be used as important diagnostics in selecting galaxy cluster candidates. Physical properties of the clusters are subsequently calculated from the X-ray observations. This sample contains the high mass and intermediate-redshift galaxy clusters for astrophysical and cosmological applications.

  14. Joint signal extraction from galaxy clusters in X-ray and SZ surveys: A matched-filter approach

    CERN Document Server

    Tarrío, Paula; Arnaud, Monique; Pratt, Gabriel W

    2016-01-01

    The hot ionized gas of the intra-cluster medium emits thermal radiation in the X-ray band and also distorts the cosmic microwave radiation through the Sunyaev-Zel'dovich (SZ) effect. Combining these two complementary sources of information through innovative techniques can therefore potentially improve the cluster detection rate when compared to using only one of the probes. Our aim is to build such a joint X-ray-SZ analysis tool, which will allow us to detect fainter or more distant clusters while maintaining high catalogue purity. We present a method based on matched multifrequency filters (MMF) for extracting cluster catalogues from SZ and X-ray surveys. We first designed an X-ray matched-filter method, analogous to the classical MMF developed for SZ observations. Then, we built our joint X-ray-SZ algorithm by combining our X-ray matched filter with the classical SZ-MMF, for which we used the physical relation between SZ and X-ray observations. We show that the proposed X-ray matched filter provides correc...

  15. Characterization of X-Ray Diffraction System with a Microfocus X-Ray Source and a Polycapillary Optic

    Science.gov (United States)

    Gubarev, Mikhail; Marshall, Joy K.; Ciszak, Ewa; Ponomarev, Igor

    2000-01-01

    We present here an optimized microfocus x-ray source and polycapillary optic system designed for diffraction of small protein crystals. The x-ray beam is formed by a 5.5mm focal length capillary collimator coupled with a 40 micron x-ray source operating at 46Watts. Measurements of the x-ray flux, the divergence and the spectral characteristics of the beam are presented, This optimized system provides a seven fold greater flux than our recently reported configuration [M. Gubarev, et al., J. of Applied Crystallography (2000) 33, in press]. We now make a comparison with a 5kWatts rotating anode generator (Rigaku) coupled with confocal multilayer focusing mirrors (Osmic, CMF12- 38Cu6). The microfocus x-ray source and polycapillary collimator system delivers 60% of the x-ray flux from the rotating anode system. Additional ways to improve our microfocus x-ray system, and thus increase the x-ray flux will be discussed.

  16. Flares in the X-ray source EXO 2030 + 375

    Science.gov (United States)

    Apparao, Krishna M. V.

    1991-01-01

    Six X-ray flares were observed in the source EXO 2030 + 375 with an average time interval of about 4 hr between the flares. It is shown here that the flares can be due to Rayleigh-Taylor instabilities near the magnetospheric boundary of the neutron star when it reaches the equilibrium period.

  17. Stellar X-ray sources in the Chandra COSMOS survey

    CERN Document Server

    Wright, Nicholas J; Civano, Francesca

    2010-01-01

    We present an analysis of the X-ray properties of a sample of solar- and late-type field stars identified in the Chandra Cosmic Evolution Survey (COSMOS), a deep (160ks) and wide (0.9 deg2) extragalactic survey. The sample of 60 sources was identified using both morphological and photometric star/galaxy separation methods. We determine X-ray count rates, extract spectra and light curves and perform spectral fits to determine fluxes and plasma temperatures. Complementary optical and near-IR photometry is also presented and combined with spectroscopy for 48 of the sources to determine spectral types and distances for the sample. We find distances ranging from 30pc to ~12kpc, including a number of the most distant and highly active stellar X-ray sources ever detected. This stellar sample extends the known coverage of the L_X-distance plane to greater distances and higher luminosities, but we do not detect as many intrinsically faint X-ray sources compared to previous surveys. Overall the sample is typically more...

  18. Compact X-ray Light Source Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    Thevuthasan, Suntharampillai; Evans, James E.; Terminello, Louis J.; Koppenaal, David W.; Manke, Kristin L.; Plata, Charity

    2012-12-01

    This report, produced jointly by EMSL and FCSD, is the result of a workshop held in September 2011 that examined the utility of a compact x-ray light source (CXLS) in addressing many scientific challenges critical to advancing energy science and technology.

  19. H0 from an orientation-unbiased sample of SZ and X-ray clusters

    CERN Document Server

    Jones, M E; Grainge, K; Grainger, W F; Kneissl, R; Pooley, G G; Saunders, R; Miyoshi, S J; Tsuruta, T; Yamashita, K; Tawara, Y; Furuzawa, A; Harada, A; Hatsukade, I; Jones, Michael E.; Edge, Alastair C.; Grainge, Keith; Grainger, William F.; Kneissl, Ruediger; Saunders, Richard; Miyoshi, Shigeru J.; Tsuruta, Taisuke; Yamashita, Koujun; Tawara, Yuzuru; Furuzawa, Akihiro; Harada, Akihiro; Hatsukade, Isamu

    2001-01-01

    We have observed the Sunyaev-Zel'dovich effect in a sample of five moderate-redshift clusters with the Ryle Telescope, and used them in conjunction with X-ray imaging and spectral data from ROSAT and ASCA to measure the Hubble constant. This sample was chosen with a strict X-ray flux limit using both the BCS and NORAS cluster catalogues to be well above the surface-brightness limit of the ROSAT All-Sky Survey, and hence to be unbiased with respect to the orientation of the cluster. This controls the major potential systematic effect in the SZ/X-ray method of measureing H0. Taking the weighted geometric mean of the results and including the main sources of random error, namely the noise in the SZ measurement, the uncertainty in the X-ray temperatures and the unknown ellipticity of the clusters, we find H0 = 59 +8/-7 km/s/Mpc assuming a standard CDM model with Omega_M = 1.0, Omega_Lambda = 0.0, or H0 = 65 +8/-7 km/s/Mpc if Omega_M = 0.3, Omega_Lambda = 0.7.

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

    CERN Document Server

    Wang, Song; Liu, Jifeng; Bregman, Joel N

    2016-01-01

    Based on the recently completed {\\it 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 for 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 ($\\alpha\\sim1.50\\pm0.07$) to elliptical ($\\sim1.21\\pm0.02$), to spirals ($\\sim0.80\\pm0.02$), to peculiars ($\\sim0.55\\pm0.30$), and to irregulars ($\\sim0.26\\pm0.10$). The XLF break dividing the neutron star and black hole binaries is also confirmed, albeit at quite different break luminosi...

  1. Discovery of a large gravitational arc in the x-ray cluster A2280

    CERN Document Server

    Gioia, I M; Luppino, G A; Clowe, D I; Böhringer, H; Briel, U G; Voges, W; Huchra, J P; MacGillivray, H T

    1995-01-01

    This Letter presents the serendipitous discovery of a large arc in an X-ray selected cluster detected in the Rosat North Ecliptic Pole (NEP) survey. The cluster, associated with Abell 2280, is identified as the optical counterpart of the X-ray source RXJ 1743.5+6341. This object is a medium--distant z=0.326 and luminous (L_(0.5-2 kev) = 5.06x10**44 erg/s) cluster dominated by a central bright galaxy. The arc is located ~ 14 arcsec to the North-West of the cD and it is detected in the R and I bands but not in the B band. Photometric and spectroscopic observations of the cluster and of the arc are presented. Other similar discoveries in the course of imaging and spectroscopic surveys of Rosat are expected in the future.

  2. An X-ray survey of clusters of galaxies

    Science.gov (United States)

    Kowalski, M. P.

    1982-03-01

    The X-ray properties of clusters of galaxies are investigated. The data were taken by the A-1 experiment aboard the HEAO 1 satellite in the 0.5 to 20 keV energy band. All clusters in both the Abell catalog and Duus and Newell southern cluster catalog were examined. An error box or an explicit upper limit was obtained for every cluster. The appendices present extensive lists of the survey results. A complete discussion of the reduction and analysis procedure is given. Supporting optical data (morphological classifications and redshifts) were obtained from the literature and included in the appendices. Each cluster in both catalogs has an estimated or measured redshift. Redshift measurements of cluster galaxies were obtained at Kitt Peak National Observatory. A complete description of these observations with the 2.1 meter telescope is given. A statistical subset of the southern catalog was defined, making it possible to combine the Abell and Southern catalogs, and thereby take advantage of the large data base afforded by the combined catalogs.

  3. Ultrafast outflows in ultraluminous X-ray sources

    CERN Document Server

    Pinto, Ciro; Middleton, Matthew; Walton, Dom

    2016-01-01

    Ultraluminous X-ray sources (ULXs) are bright extragalactic sources with X-ray luminosities above 10^39 erg/s powered by accretion onto compact objects. According to the first studies performed with XMM-Newton ULXs seemed to be excellent candidates to host intermediate-mass black holes (10^2-4 solar masses). However, in the last years the interpretation of super-Eddington accretion onto stellar-mass black holes or neutron stars for most ULXs has gained a strong consensus. One critical missing piece to confirm the super-Eddington scenario was the direct detection of the massive, radiatively-driven winds expected as atomic emission/absorption lines in ULX spectra. The first evidence for winds was found as residuals in the soft X-ray spectra of ULXs. Most recently we have been able to resolve these residuals into rest-frame emission and blueshifted (~0.2c) absorption lines arising from highly ionized gas in the deep high-resolution XMM-Newton spectra of two ultraluminous X-ray sources. The compact object is ther...

  4. Low-Mass X-ray Binaries and Globular Clusters in Centaurus A

    CERN Document Server

    Jordan, Andres; McLaughlin, Dean E; Blakeslee, John P; Evans, Daniel A; Kraft, Ralph P; Hardcastle, Martin J; Peng, Eric W; Cote, Patrick; Croston, Judith H; Juett, Adrienne M; Minniti, Dante; Raychaudhury, Somak; Sarazin, Craig L; Worrall, Diana M; Harris, William E; Woodley, Kristin A; Birkinshaw, Mark; Brassington, Nicola J; Forman, William R; Jones, Christine; Murray, Stephen S

    2007-01-01

    We present results of Hubble Space Telescope and Chandra X-ray Observatory observations of globular clusters (GCs) and low-mass X-ray binaries (LMXBs) in the central regions of Centaurus A. Out of 440 GC candidates we find that 41 host X-ray point sources that are most likely LMXBs. We fit King models to our GC candidates in order to measure their structural parameters. We find that GCs that host LMXBs are denser and more compact, and have higher encounter rates and concentrations than the GC population as a whole. We show that the higher concentrations and masses are a consequence of the dependence of LMXB incidence on central density and size plus the general trend for denser GCs to have higher masses and concentrations. We conclude that neither concentration nor mass are fundamental variables in determining the presence of LMXBs in GCs, and that the more fundamental parameters relate to central density and size.

  5. X-ray and Optical Study of Low Core Density Globular Clusters NGC6144 and E3

    CERN Document Server

    Lan, Shih Hao; Verbunt, Frank; Lewin, Walter H G; Bassa, Cees; Anderson, Scott F; Pooley, David

    2009-01-01

    We report on the Chandra X-ray Observatory and Hubble Space Telescope observation of two low core density globular clusters, NGC6144 and E3. By comparing the number of X-ray sources inside the half-mass radius to those outside, we found 6 X-ray sources within the half-mass radius of NGC6144, among which 4 are expected to be background sources; 3 X-ray sources are also found within the half-mass radius of E3, of which 3 is expected to be background source. Therefore, we cannot exclude that all our sources are background sources. However, combining the results from X-ray and optical observations, we found that 1-2 sources in NGC6144 and 1 source in E3 are likely to be cataclysmic variables and that 1 source in NGC6144 is an active binary, based on the X-ray and optical properties. The number of faint X-ray sources in NGC6144 and E3 found with Chandra and HST is higher than a prediction based on collision frequency, but is closer to that based on mass. Our observations strongly suggest that the compact binary sy...

  6. Hard X-ray Sources for the Mexican Synchrotron Project

    Science.gov (United States)

    Reyes-Herrera, Juan

    2016-10-01

    One of the principal tasks for the design of the Mexican synchrotron was to define the storage ring energy. The main criteria for choosing the energy come from studying the electromagnetic spectrum that can be obtained from the synchrotron, because the energy range of the spectrum that can be obtained will determine the applications available to the users of the future light source. Since there is a public demand of hard X-rays for the experiments in the synchrotron community users from Mexico, in this work we studied the emission spectra from some hard X-ray sources which could be the best options for the parameters of the present Mexican synchrotron design. The calculations of the flux and the brightness for one Bending Magnet and four Insertion Devices are presented; specifically, for a Superconducting Bending Magnet (SBM), a Superconducting Wiggler (SCW), an In Vacuum Short Period Undulator (IV-SPU), a Superconducting Undulator (SCU) and for a Cryogenic Permanent Magnet Undulator (CPMU). Two commonly available synchrotron radiation programs were used for the computation (XOP and SRW). From the results, it can be concluded that the particle beam energy from the current design is enough to have one or more sources of hard X-rays. Furthermore, a wide range of hard X-ray region can be covered by the analyzed sources, and the choice of each type should be based on the specific characteristics of the X-ray beam to perform the experiments at the involved beamline. This work was done within the project Fomix Conacyt-Morelos ”Plan Estrategico para la construccion y operación de un Sincrotron en Morelos” (224392).

  7. Unifying X-ray Scaling Relations from Galaxies to Clusters

    CERN Document Server

    Anderson, Michael E; White, Simon D M; Wang, Wenting; Dai, Xinyu

    2014-01-01

    We examine a sample of $\\sim 250 000$ "locally brightest galaxies" selected from the Sloan Digital Sky Survey to be central galaxies within their dark matter halos. These were previously stacked by the Planck Collaboration to measure the Sunyaev-Zel'dovich signal as a function of central galaxy stellar mass. Here, we stack the X-ray emission from these halos using data from the ROSAT All-Sky Survey. We detect emission across almost our entire sample, including emission which we attribute to hot gas around galaxies spanning a range of 1.2 dex in stellar mass (corresponding to nearly two orders of magnitude in halo mass) down to $M* = 10^{10.8} M_{\\odot}$ ($M_{500} \\approx 10^{12.6} M_{\\odot}$). Over this range, the X-ray luminosity can be fit by a power-law, either of stellar mass or of halo mass. A single unified scaling relation between mass and $L_X$ applies for galaxies, groups, and clusters. This relation has a steeper slope than expected for self-similarity, in contrast to the $Y_{SZ}$-$M_{500}$ relation...

  8. Automatic classification of time-variable X-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Kitty K.; Farrell, Sean; Murphy, Tara; Gaensler, B. M. [Sydney Institute for Astronomy, School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

    2014-05-01

    To maximize the discovery potential of future synoptic surveys, especially in the field of transient science, it will be necessary to use automatic classification to identify some of the astronomical sources. The data mining technique of supervised classification is suitable for this problem. Here, we present a supervised learning method to automatically classify variable X-ray sources in the Second XMM-Newton Serendipitous Source Catalog (2XMMi-DR2). Random Forest is our classifier of choice since it is one of the most accurate learning algorithms available. Our training set consists of 873 variable sources and their features are derived from time series, spectra, and other multi-wavelength contextual information. The 10 fold cross validation accuracy of the training data is ∼97% on a 7 class data set. We applied the trained classification model to 411 unknown variable 2XMM sources to produce a probabilistically classified catalog. Using the classification margin and the Random Forest derived outlier measure, we identified 12 anomalous sources, of which 2XMM J180658.7–500250 appears to be the most unusual source in the sample. Its X-ray spectra is suggestive of a ultraluminous X-ray source but its variability makes it highly unusual. Machine-learned classification and anomaly detection will facilitate scientific discoveries in the era of all-sky surveys.

  9. AGN content of X-ray, IR and radio sources

    Science.gov (United States)

    Mickaelian, A. M.; Paronyan, G. M.; Abrahamyan, H. V.; Gyulzadyan, M. V.; Mikayelyan, G. A.

    2016-09-01

    We have carried out a number of surveys and identification works related to X-ray, IR and radio sources and searched for extragalactic ones. Among them, most interesting are Active Galactic Nuclei (AGN) and Starburst (SB) Galaxies. Some 4500 AGN have been revealed from ROSAT BSC and FSC sources, and many more are hidden ones; those showing evidence of activity but with no emission lines in optical wavelengths. We estimated AGN content of X-ray sources as 52.9%. IR sources contain thousands of SBs, and most important are those having signs of interaction and/or merging. We have carried out optical identifications of IRAS point sources, and 1278 IR galaxies have been revealed, including LIRGs and ULIRGs. We have also combined IRAS PSC and FSC catalogs and compiled its extragalactic sample, which allowed to estimate AGN content among IR sources as 23.7%. Extragalactic radio sources contain bright galaxies, AGN and SBs. We have studied the border between AGN and normal galaxies by radio/optical flux ratios to establish which objects may be attributed to AGN based on radio properties. Interestingly, absolute majority of objects associated with both X-ray and radio sources are AGN.

  10. An Automated Census Of Variable X-Ray Objects in the Direction of Clusters of Galaxies

    Science.gov (United States)

    MacIntosh, Lupe; Cunningham, Elizabeth; Ulmer, Melville P.

    2017-01-01

    Since the launch of the Chandra X-ray Observatory in 1999, broad x-ray surveys have been the primary means of discovering new objects in the sky. We present the results of one such survey, examining variable x-ray sources in archival Chandra data. Our survey maximizes the possibility of finding novel and interesting sources by searching for all x-ray variable sources and manually categorizing variable objects. This allows for the identification of interesting objects with common classifications, like a typical galaxy with unusual fluctuations. To further increase the probability of finding sources we focused on galaxy clusters, allowing us to look at over a thousand galaxies per observation. Our analysis was based on a previously compiled database of source fluxes, over all available observations and across energies from 0.2 keV to 12 keV. We converted the soft x-ray flux (0.5 to 2 keV) to count rate, then fit it to the average count rate using least squares regression. Variable sources are defined as those with c2 > 50 over the total observed time. We then categorized variable objects and found optical counterparts. Our criteria identified 49 variable sources from a total of 58,000 sources in our database, though we estimate up to 20% of the database is extraneous double sources. Of these variable sources, 9 had not been previously identified in the SIMBAD database and 28 had not been previously categorized as variable. A majority of the objects found were expected, such as various classes of active galactic nuclei and variable red dwarfs. Other more interesting objects include a variable A-type star and an ultraluminous galaxy.

  11. High power bremsstrahlung X-ray source for radiation processing

    Science.gov (United States)

    Yotsumoto, K.; Sunaga, H.; Tanaka, S.; Kanazawa, T.; Agematsu, T.; Tanaka, R.; Yoshida, K.; Taniguchi, S.; Sakamoto, I.; Tamura, N.

    The high power X-ray irradiation facility designed for the sterilization of medical appliances is described. The X-ray source consists of the 5 MeV, 300 kW Cockcroft Walton type of electron accelerator and the water cooled tantalum target. Conditions necessary for designing the X-ray target are conversion efficiency from electron beam to X-ray, thermal conductivity, readiness for machining and cost of the material. The conversion efficiency was determined through the Monte Carlo type calculation and obtained as 10.8 % for 3.667 g/cm 2 thickness (1 csda range) of tantalum target. In order to obtain the data on the source design, experiments have been carried out at the JAERI TAKASAKI 2 MeV, 60 kW Cockcroft-Walton type of electron accelerator equipped with a tantalum target. The size of package and the speed of conveyor was determined through the calculation of the absorbed dose distribution in the irradiated medium and the utilization efficiency.

  12. Near-Infrared Spectroscopy of Faint Discrete X-ray Point Sources Constituting the Galactic Ridge X-ray Emission

    CERN Document Server

    Morihana, Kumiko; Dubath, Pierre; Yoshida, Tessei; Suzuki, Kensuke; Ebisawa, Ken

    2016-01-01

    The Galactic Ridge X-ray Emission (GRXE) is apparently extended X-ray emission along the Galactic Plane. The X-ray spectrum is characterized by hard continuum with a strong Fe K emission feature in the 6-7 keV band. A substantial fraction (~80%) of the GRXE in the Fe band was resolved into point sources by deep Chandra imaging observations, thus GRXE is mostly composed of dim Galactic X-ray point sources at least in this energy band. To investigate the populations of these dim X-ray point sources, we carried out Near-Infrared (NIR) follow-up spectroscopic observations in two deep Chandra fields located in the Galactic plane at (l,b)=(0.1{\\arcdeg}, -1.4{\\arcdeg}) and (28.5{\\arcdeg}, 0.0{\\arcdeg}) using NTT/SofI and Subaru/MOIRCS. We obtained well-exposed NIR spectra from 65 objects and found that there are three main classes of Galactic sources based on the X-ray color and NIR spectral features: those having (A) hard X-ray spectra and NIR emission features such as HI(Br{\\gamma}), HeI, and HeII (2 objects), (B)...

  13. A Comparison of Radio and X-Ray Morphologies of Four Clusters of Galaxies Containing Radio Halos

    CERN Document Server

    Govoni, F; Feretti, L; Giovannini, G

    2001-01-01

    Clusters of galaxies may contain cluster-wide, centrally located, diffuse radio sources, called halos. They have been found to show morphologies similar to those of the X-ray emission. To quantify this qualitative statement we performed a point-to-point comparison of the radio and the X-ray emission for four clusters of galaxies containing radio halos: Coma, Abell 2255, Abell 2319, Abell 2744. Our study leads to a linear relation between the radio and the X-ray surface brightness in two clusters, namely Abell 2255 and Abell 2744. In Coma and A2319 the radio and the X-ray brightnesses seem to be related with a sub-linear power law. Implications of these findings within simple radio halo formation models are briefly discussed.

  14. The baryon content of distant X-ray Galaxy Clusters

    Science.gov (United States)

    Santos, Joana

    In the framework of the current cosmological paradigm, cosmic evolution is mostly driven by gravity through the hierarchical growth of cold dark matter structures. However, the evolution of the directly observed luminous component involves complex non-gravitational processes such as cooling, star formation and feedback mechanisms involving the conventional matter well known to us, termed shortly as baryons. Clusters of galaxies are the largest virialized systems in the Universe, hence are ideal laboratories to study the evolution of baryons. The baryon content of clusters accounts for roughly 15% of their total mass, encompassing a "cold phase" in the form of luminous galaxy masses, and a "hot phase" corresponding to the X-ray emitting intracluster medium (ICM). The thermodynamics of baryons is affected by non-trivial phenomena and the interplay of the intricate processes between these two phases remains, to a large extent, unclear. In this thesis I investigate the properties of both the ICM and the underlying galaxy populations in X-ray selected distant clusters, with the aim of constraining physical processes governing the evolution of clusters and their galaxies. The inner regions of local clusters often exhibit radiative cooling, termed cool cores (CC). I have made an important step in investigating the abundance of cool cores in the distant cluster population, by devising efficient methods to characterize local CCs, that were applied to the highest redshift cluster sample currently available (0.7 1) clusters are hard to find. The XMM-Newton Distant Cluster Project (XDCP) is a survey aimed to construct a complete sample of z ˜-1 clusters from the XMM-Newton archive. Within this scope a large effort has been done to confirm potential distant cluster candidates by exploring a new optical & near-infrared imaging technique to identify overdensities of galaxies. Twenty-two cluster candidates were imaged during two runs at the ESO/La Silla Observatory, of which

  15. High-Resolution Chandra X-ray Imaging and Spectroscopy of the Sigma Orionis Cluster

    CERN Document Server

    Skinner, S L; Cohen, D H; Gagné, M; Owocki, S P; Townsend, R D

    2008-01-01

    We present results of a 90 ksec Chandra X-ray observation of the young sigma Orionis cluster (age ~3 Myr) obtained with the High Energy Transmission Grating Spectrometer. We use the high resolution grating spectrum and moderate resolution CCD spectrum of the massive central star sigma Ori AB (O9.5V + B0.5V) to test wind shock theories of X-ray emission and also analyze the high spatial resolution zero-order ACIS-S image of the central cluster region. Chandra detected 42 X-ray sources on the primary CCD (ACIS-S3). All but five have near-IR or optical counterparts and about one-fourth are variable. Notable high-mass stellar detections are sigma Ori AB, the magnetic B star sigma Ori E, and the B5V binary HD 37525. Most of the other detections have properties consistent with lower mass K or M-type stars. We present the first X-ray spectrum of the unusual infrared source IRS1 located 3.3 arc-sec north of sigma Ori AB, which is likely an embedded T Tauri star whose disk/envelope is being photoevaporated by sigma Or...

  16. X-ray Clusters of Galaxies as Cosmological Tools

    CERN Document Server

    Gioia, Isabella Maria

    2009-01-01

    This paper was written as part of a book entitled: "Questions of Modern Cosmology - Galileo's Legacy" which is a celebrative book dedicated to Galileo Galilei. The book is published in 2009, the International Year of Astronomy, since it is intended to be a modern tribute to the astronomer who, 400 years ago, first pointed a telescope towards the night sky. The book is written in the form of interviews between the editors and many physicists, astrophysicists and cosmologists from all over the world. The editors engaged in several discussions on the formation and evolution of the Universe with the aim of summarizing the most important and significative advances made by cosmology over the past century and at the beginning of the new millennium. This paper deals with X-ray clusters of galaxies and how they can be used to constrain fundamental cosmological parameters.

  17. X-ray Cluster Constraints on Non-Gaussianity

    CERN Document Server

    Shandera, Sarah; Rapetti, David; Allen, Steven W

    2013-01-01

    We report constraints on primordial non-Gaussianity from the abundance of X-ray detected clusters. Our analytic prescription for adding non-Gaussianity to the cluster mass function takes into account moments beyond the skewness, and we demonstrate that those moments should not be ignored in most analyses of cluster data. We constrain the amplitude of the skewness for two scenarios that have different overall levels of non-Gaussianity, characterized by how amplitudes of higher cumulants scale with the skewness. We find that current data can constrain these one-parameter non-Gaussian models at a useful level, but are not sensitive to adding further details of the corresponding inflation scenarios. Combining cluster data with Cosmic Microwave Background constraints on the cosmology and power spectrum amplitude, we find the dimensionless skewness to be 1000*M3=-1+24-28 for one of our scaling scenarios, and 1000*M3=-4+/-7 for the other. These are the first constraints on non-Gaussianity from Large Scale Structure ...

  18. Distributed source x-ray tube technology for tomosynthesis imaging

    Science.gov (United States)

    Sprenger, F.; Calderon-Colon, X.; Cheng, Y.; Englestad, K.; Lu, J.; Maltz, J.; Paidi, A.; Qian, X.; Spronk, D.; Sultana, S.; Yang, G.; Zhou, O.

    2010-04-01

    Tomosynthesis imaging requires projection images from different viewing angles. Conventional systems use a moving xray source to acquire the individual projections. Using a stationary distributed x-ray source with a number of sources that equals the number of required projections, this can be achieved without any mechanical motion. Advantages are a potentially faster image acquisition speed, higher spatial and temporal resolution and simple system design. We present distributed x-ray sources based on carbon nanotube (CNT) field emission cathodes. The field emission cathodes deliver the electrons required for x-ray production. CNT emitters feature a stable emission at high current density, a cold emission, excellent temporal control of the emitted electrons and good configurability. We discuss the use of stationary sources for two applications: (i) a linear tube for stationary digital breast tomosynthesis (sDBT), and (ii) a square tube for on-board tomosynthesis image-guided radiation therapy (IGRT). Results from high energy distributed sources up to 160kVp are also presented.

  19. ISO investigates the nature of extremely-red hard X-ray sources responsible for the X-ray background

    CERN Document Server

    Franceschini, A; Césarsky, C J; Elbaz, D; Flores, H; Granato, G L; Franceschini, Alberto; Fadda, Dario; Cesarsky, Catherine; Elbaz, David; Flores, Hector; Granato, Gian Luigi

    2001-01-01

    We analyse very deep X-ray and mid-IR surveys in common areas of the Lockman Hole and the HDF North to study the sources of the X-ray background (XRB) and to test the standard obscured accretion paradigm. We detect with ISO a rich population of X-ray luminous sources with red optical colours, including a fraction identified with Extremely Red Objects (R-K > 5) and galaxies with SEDs typical of normal massive ellipticals or spirals at z ~ 1. The high 0.5-10 keV X-ray luminosities of these objects (1E43-1E45 erg/s) indicate that the ultimate energy source is gravitational accretion, while the X-ray to IR flux ratios and the X-ray spectral hardness show evidence of photoelectric absorption at low X-ray energies. An important hint on the physics comes from the mid-IR data at 6.7 and 15 um, well reproduced by model spectra of completely obscured quasars under standard assumptions and l.o.s. optical depths tau ~ 30-40. Other predictions of the standard XRB picture, like the distributions of intrinsic bolometric lum...

  20. Measuring x-ray spectra of flash radiographic sources

    Science.gov (United States)

    Gehring, Amanda E.; Espy, Michelle A.; Haines, Todd J.; Mendez, Jacob; Moir, David C.; Sedillo, Robert; Shurter, Roger P.; Volegov, Petr; Webb, Timothy J.

    2015-08-01

    A Compton spectrometer has been re-commissioned for measurements of flash radiographic sources. The determination of the energy spectrum of these sources is difficult due to the high count rates and short nature of the pulses (~50 ns). The spectrometer is a 300 kg neodymium-iron magnet which measures spectra in the <1 MeV to 20 MeV energy range. Incoming x-rays are collimated into a narrow beam incident on a converter foil. The ejected Compton electrons are collimated so that the forward-directed electrons enter the magnetic field region of the spectrometer. The position of the electrons at the magnet's focal plane is a function of their momentum, allowing the x-ray spectrum to be reconstructed. Recent measurements of flash sources are presented.

  1. High duty cycle inverse Compton scattering X-ray source

    Science.gov (United States)

    Ovodenko, A.; Agustsson, R.; Babzien, M.; Campese, T.; Fedurin, M.; Murokh, A.; Pogorelsky, I.; Polyanskiy, M.; Rosenzweig, J.; Sakai, Y.; Shaftan, T.; Swinson, C.

    2016-12-01

    Inverse Compton Scattering (ICS) is an emerging compact X-ray source technology, where the small source size and high spectral brightness are of interest for multitude of applications. However, to satisfy the practical flux requirements, a high-repetition-rate ICS system needs to be developed. To this end, this paper reports the experimental demonstration of a high peak brightness ICS source operating in a burst mode at 40 MHz. A pulse train interaction has been achieved by recirculating a picosecond CO2 laser pulse inside an active optical cavity synchronized to the electron beam. The pulse train ICS performance has been characterized at 5- and 15- pulses per train and compared to a single pulse operation under the same operating conditions. With the observed near-linear X-ray photon yield gain due to recirculation, as well as noticeably higher operational reliability, the burst-mode ICS offers a great potential for practical scalability towards high duty cycles.

  2. The Swift X-ray Telescope Cluster Survey: data reduction and cluster catalog for the GRB fields

    CERN Document Server

    Tundo, Elena; Tozzi, Paolo; Teng, Liu; Rosati, Piero; Tagliaferri, Gianpiero; Campana, Sergio

    2012-01-01

    (abridged) We present a new sample of X-ray selected galaxy groups and clusters serendipitously observed with Swift and the X-ray Telescope (XRT). We searched the XRT archive for extended sources among 336 GRB fields with galactic latitude |b|>20{\\deg}. Our selection algorithm yields a flux-limited sample of 72 X-ray groups and clusters with a well defined selection function and negligible contamination. The sky coverage of the survey goes from the total 40 deg^2 to 1 deg^2 at a flux limit of 10^-14 erg/s/cm^-2 (0.5-2 keV). Here we describe the XRT data processing, the statistical calibration of the survey, and the catalog of detected cluster candidates. All the X-ray sources are detected in the Swift-XRT soft (0.5-2 keV) band. A size parameter defined as the half power radius (HPR) measured inside a box of 45x45 arcsec, is assigned to each source. We select extended sources by applying a threshold on the Half Power Radius and we calibrate its dependence on the measured net counts and on the image background ...

  3. Laser-driven soft-X-ray undulator source

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Matthias

    2010-08-04

    The experimental results described in this thesis demonstrate the successful synergy between the research fields described above: the development of an undulator source driven by laser-plasma accelerated electron beams. First efforts in this new field have led to the production of radiation in the visible to infrared part of the electromagnetic spectrum [Schlenvoigt et al., 2008]. In contrast to these early achievements, the experiment described here shows the successful production of laser-driven undulator radiation in the soft-X-ray range with a remarkable reproducibility. The source produced tunable, collimated beams with a wavelength of {proportional_to}17 nm from a compact setup. Undulator spectra were detected in {proportional_to}70% of consecutive driver-laser shots, which is a remarkable reproducibility for a first proof-of-concept demonstration using ultra-high intensity laser systems. This can be attributed to a stable electron acceleration scheme as well as to the first application of miniature magnetic quadrupole lenses with laseraccelerated beams. The lenses significantly reduce the electron beam divergence and its angular shot-to-shot fluctuations The setup of this experiment is the foundation of potential university-laboratory-sized, highly-brilliant hard X-ray sources. By increasing the electron energy to about 1 GeV, X-ray pulses with an expected duration of {proportional_to}10 fs and a photon energy of 1 keV could be produced in an almost identical arrangement. It can also be used as a testbed for the development of a free-electron laser of significantly smaller dimension than facilities based on conventional accelerators [Gruener et al., 2007]. Such compact sources have the potential for application in many fields of science. In addition, these developments could lead to ideal sources for ultrafast pump-probe experiments due to the perfect synchronization of the X-ray beam to the driver laser. (orig.)

  4. Chandra X-ray Observations of the Young Stellar Cluster NGC 6193 in the Ara OB1 Association

    CERN Document Server

    Skinner, S L; Palla, F; Barbosa, C L D R

    2005-01-01

    A 90 ks Chandra HETG observation of the young stellar cluster NGC 6193 in the southern Ara OB1 association detected 43 X-ray sources in a 2' x 2' core region centered on the young O stars HD 150135 (O6.5V) and HD 150136 (O3+O6V). The cluster is dominated by exceptionally bright X-ray emission from the two O stars, which are separated by only 10 arcsecs. The X-ray luminosity of HD 150136 is log Lx = 33.39 (ergs/s), making it one of the most luminous O-star X-ray sources known. All of the fainter X-ray sources in the core region have near-IR counterparts, but JHK photometry provides little evidence for near-IR excesses. These core sources have typical mean photon energies of 2 keV and about one-third are variable. It is likely that some are young low-mass stars in the cluster, but cluster membership remains to be determined. Grating spectra show that the X-ray properties of HD 150135 and HD 150136 are similar, but not identical. Both have moderately broadened unshifted emission lines and their emission is domin...

  5. The Polarimeter for Relativistic Astrophysical X-ray Sources

    Science.gov (United States)

    Jahoda, Keith; Kallman, Timothy R.; Kouveliotou, Chryssa; Angelini, Lorella; Black, J. Kevin; Hill, Joanne E.; Jaeger, Theodore; Kaaret, Philip E.; Markwardt, Craig B.; Okajima, Takashi; Petre, Robert; Schnittman, Jeremy; Soong, Yang; Strohmayer, Tod E.; Tamagawa, Toru; Tawara, Yuzuru

    2016-07-01

    The Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) is one of three Small Explorer (SMEX) missions selected by NASA for Phase A study, with a launch date in 2020. The PRAXyS Observatory exploits grazing incidence X-ray mirrors and Time Projection Chamber Polarimeters capable of measuring the linear polarization of cosmic X-ray sources in the 2-10 keV band. PRAXyS combines well-characterized instruments with spacecraft rotation to ensure low systematic errors. The PRAXyS payload is developed at the Goddard Space Flight Center with the Johns Hopkins University Applied Physics Laboratory, University of Iowa, and RIKEN (JAXA) collaborating on the Polarimeter Assembly. The LEOStar-2 spacecraft bus is developed by Orbital ATK, which also supplies the extendable optical bench that enables the Observatory to be compatible with a Pegasus class launch vehicle. A nine month primary mission will provide sensitive observations of multiple black hole and neutron star sources, where theory predicts polarization is a strong diagnostic, as well as exploratory observations of other high energy sources. The primary mission data will be released to the community rapidly and a Guest Observer extended mission will be vigorously proposed.

  6. Kinematics of Compton backscattering x-ray source for angiography

    Energy Technology Data Exchange (ETDEWEB)

    Blumberg, L.N.

    1992-05-01

    Calculations of X-Ray production rates, energy spread, and spectrum of Compton-backscattered photons from a Free Electron Laser on an electron beam in a low energy (136-MeV) compact (8.5-m circumference) storage ring indicate that an X-Ray intensity of 34.6 10{sup 7} X-Ray photons per 0.5-mm {times} 0.5-mm pixel for Coronary Angiography near the 33.169-keV iodine K-absorption edge can be achieved in a 4-msec pulse within a scattering cone of 1-mrad half angle. This intensity, at 10-m from the photon-electron interaction point to the patient is about a factor of 10 larger than presently achieved from a 4.5-T superconducting wiggler source in the NSLS 2.5-GeV storage ring and over an area about 5 times larger. The 2.2-keV energy spread of the Compton-backscattered beam is, however, much larger than the 70-eV spread presently attained form the wiggler source and use of a monochromator. The beam spot at the 10-m interaction point-to-patient distance is 20-mm diameter; larger spots are attainable at larger distances but with a corresponding reduction in X-Ray flux. Such a facility could be an inexpensive clinical alternative to present methods of non-invasive Digital Subtraction Angiography (DSA), small enough to be deployed in an urban medical center, and could have other medical, industrial and aerospace applications. Problems with the Compton backscattering source include laser beam heating of the mirror in the FEL oscillator optical cavity, achieving a large enough X-Ray beam spot at the patient, and obtaining radiation damping of the transverse oscillations and longitudinal emittance dilution of the storage ring electron beam resulting from photon-electron collisions without going to higher electron energy where the X-Ray energy spread becomes excessive for DSA. 38 refs.

  7. THE SWIFT X-RAY TELESCOPE CLUSTER SURVEY. III. CLUSTER CATALOG FROM 2005-2012 ARCHIVAL DATA

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Teng; Wang, Jun-Xian [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, 230026 Hefei, Anhui (China); Tozzi, Paolo; Tundo, Elena [INAF, Osservatorio Astrofisico di Firenze, Largo Enrico Fermi 5, I-50125 Firenze (Italy); Moretti, Alberto [INAF, Osservatorio Astronomico di Brera, Via Brera 28, I-20121 Milano (Italy); Rosati, Piero [Università degli Studi di Ferrara, Dipartimento di Fisica e Scienze della Terra, Via Saragat 1, I-44121 Ferrara (Italy); Tagliaferri, Gianpiero; Campana, Sergio [INAF, Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate (Italy); Giavalisco, Mauro, E-mail: liuteng@ustc.edu.cn [Department of Astronomy, University of Massachusetts, LGRT-B 619E, 710 North Pleasant Street, Amherst, MA (United States)

    2015-02-01

    We present the Swift X-ray Cluster Survey (SWXCS) catalog obtained using archival data from the X-ray telescope (XRT) on board the Swift satellite acquired from 2005 February to 2012 November, extending the first release of the SWXCS. The catalog provides positions, soft fluxes, and, when possible, optical counterparts for a flux-limited sample of X-ray group and cluster candidates. We consider the fields with Galactic latitude |b| > 20° to avoid high H I column densities. We discard all of the observations targeted at groups or clusters of galaxies, as well as particular extragalactic fields not suitable to search for faint extended sources. We finally select ∼3000 useful fields covering a total solid angle of ∼400 deg{sup 2}. We identify extended source candidates in the soft-band (0.5-2 keV) images of these fields using the software EXSdetect, which is specifically calibrated for the XRT data. Extensive simulations are used to evaluate contamination and completeness as a function of the source signal, allowing us to minimize the number of spurious detections and to robustly assess the selection function. Our catalog includes 263 candidate galaxy clusters and groups down to a flux limit of 7 × 10{sup –15} erg cm{sup –2} s{sup –1} in the soft band, and the logN-logS is in very good agreement with previous deep X-ray surveys. The final list of sources is cross-correlated with published optical, X-ray, and Sunyaev-Zeldovich catalogs of clusters. We find that 137 sources have been previously identified as clusters in the literature in independent surveys, while 126 are new detections. Currently, we have collected redshift information for 158 sources (60% of the entire sample). Once the optical follow-up and the X-ray spectral analysis of the sources are complete, the SWXCS will provide a large and well-defined catalog of groups and clusters of galaxies to perform statistical studies of cluster properties and tests of cosmological models.

  8. First Search for an X-ray -- Optical Reverberation Signal in an Ultraluminous X-ray Source

    CERN Document Server

    Pasham, Dheeraj R; Cenko, S Bradley; Trippe, Margaret L; Mushotzky, Richard F; Gandhi, Poshak

    2016-01-01

    Using simultaneous optical (VLT/FORS2) and X-ray (XMM-Newton) data of NGC 5408, we present the first ever attempt to search for a reverberation signal in an ultraluminous X-ray source (NGC 5408 X-1). The idea is similar to AGN broad line reverberation mapping where a lag measurement between the X-ray and the optical flux combined with a Keplerian velocity estimate should enable us to weigh the central compact object. We find that although NGC 5408 X-1's X-rays are variable on a timescale of a few hundred seconds (RMS of 9.0$\\pm$0.5%), the optical emission does not show any statistically significant variations. We set a 3$\\sigma$ upper limit on the RMS optical variability of 3.3%. The ratio of the X-ray to the optical variability is an indicator of X-ray reprocessing efficiency. In X-ray binaries, this ratio is roughly 5. Assuming a similar ratio for NGC 5408 X-1, the expected RMS optical variability is $\\approx$2% which is still a factor of roughly two lower than what was possible with the VLT observations in...

  9. Geometry calibration between X-ray source and detector for tomosynthesis with a portable X-ray system.

    Science.gov (United States)

    Sato, Kohei; Ohnishi, Takashi; Sekine, Masashi; Haneishi, Hideaki

    2017-05-01

    Tomosynthesis is attracting attention as a low-dose tomography technology compared with X-ray CT. However, conventional tomosynthesis imaging devices are large and stationary. Furthermore, there is a limitation in the working range of the X-ray source during image acquisition. We have previously proposed the use of a portable X-ray device for tomosynthesis that can be used for ward rounds and emergency medicine. The weight of this device can be reduced by using a flat panel detector (FPD), and flexibility is realized by the free placement of the X-ray source and FPD. Tomosynthesis using a portable X-ray device requires calibration of the geometry between the X-ray source and detector at each image acquisition. We propose a method for geometry calibration and demonstrate tomosynthesis image reconstruction by this method. An image processing-based calibration method using an asymmetric and multilayered calibration object (AMCO) is presented. Since the AMCO is always attached to the X-ray source housing for geometry calibration, the additional setting of a calibration object or marker around or on the patients is not required. The AMCO's multilayer structure improves the calibration accuracy, especially in the out-of-plane direction. Two experiments were conducted. The first was performed to evaluate the calibration accuracy using an XY positioning stage and a gonio stage. As a result, an accuracy of approximately 1 mm was achieved both in the in-plane and out-of-plane directions. An angular accuracy of approximately [Formula: see text] was confirmed. The second experiment was conducted to evaluate the reconstructed image using a foot model phantom. Only the sagittal plane could be clearly observed with the proposed method. We proposed a tomosynthesis imaging system using a portable X-ray device. From the experimental results, the proposed method could provide sufficient calibration accuracy and a clear sagittal plane of the reconstructed tomosynthesis image.

  10. Towards brilliant, compact x-ray sources: a new x-ray photonic device

    Science.gov (United States)

    Scherer, Brian; Mandal, Sudeep; Salisbury, Joshua; Edic, Peter; Hopkins, Forrest; Lee, Susanne M.

    2017-05-01

    General Electric has designed an innovative x-ray photonic device that concentrates a polychromatic beam of diverging x-rays into a less divergent, parallel, or focused x-ray beam. The device consists of multiple, thin film multilayer stacks. X-rays incident on a given multilayer stack propagate within a high refractive index transmission layer while undergoing multiple total internal reflections from a novel, engineered multilayer containing materials of lower refractive index. Development of this device could lead to order-of-magnitude flux density increases, over a large broadband energy range from below 20 keV to above 300 keV. In this paper, we give an overview of the device and present GE's progress towards fabricating prototype devices.

  11. Non-Nuclear Hyper/Ultraluminous X-Ray Sources in the Starbursting Cartwheel Ring Galaxy

    CERN Document Server

    Gao, Y; Appleton, P N; Lucas, R A; Gao, Yu; Lucas, Ray A.

    2003-01-01

    We report the Chandra/ACIS-S detection of more than 20 ultraluminous X-ray sources (ULXs, L_{0.5-10 keV} >~ 3 x 10^{39} ergs/sec) in the Cartwheel collisional ring galaxy system, of which over a dozen are located in the outer active star-forming ring. A remarkable hyperluminous X-ray source (HLX, L_{0.5-10 keV} >~ 10^{41} ergs/sec assuming isotropic radiation), which dominates the X-ray emission from the Cartwheel ring, is located in the same segment of the ring as most ULXs. These powerful H/ULXs appear to be coincident with giant HII region complexes, young star clusters, and radio and mid-infrared hot-spots: all strong indicators of recent massive star formation. The X-ray spectra show that H/ULXs have similar properties as those of the {\\it most luminous} ULXs found in the nearest starbursts and galaxy mergers such as the Antennae galaxies and M82. The close association between the X-ray sources and the starbursting ring strongly suggests that the H/ULXs are intimately associated with the production and r...

  12. Ultraluminous X-ray Sources in Interacting Galaxies

    CERN Document Server

    Swartz, Douglas A

    2009-01-01

    I give a brief review of how X-rays from nearby galaxies are used as direct tracers of recent star formation. This leads to the conclusion that it is the most luminous point-like sources that are associated with star formation and that the majority of these are high-mass X-ray binaries.I then discuss a recent study that shows that ULXs are preferentially found in regions as young as or younger than typical HII regions in their host galaxies. Finally, I describe a new study that attempts to determine the maximum luminosity of ULXs in the local universe by searching for them in interacting galaxies where the star formation rate is high.

  13. Reionization by UV or X-ray sources

    CERN Document Server

    Baek, S; Di Matteo, P; Revaz, Y; Combes, F

    2010-01-01

    We present simulations of the 21-cm signal during the Epoch of reionization. We focus on modeling properly the absorption regime in the presence of inhomogeneous Wouthuysen-Field effect and X-ray heating. We have run radiative transfer simulations for three bands in the source spectrum (Lyman, UV and X-ray) in order to fully account for these processes. We find that the brightness temperature fluctuation of the 21 cm signal has an amplitude larger than 100 mK during the early reionization, up to 10 times higher than the typical amplitude of a few 10 mK obtained during the later emission phase. More importantly, we find that even a rather high contribution from QSO-like sources only damps the absorption regime without erasing it. Heating the IGM with X-ray takes time. Our results show that observations of the early reionization will probably benefit from a higher signal-to-noise value than during later stages. Analyzing the statistical properties of the signal (power spectrum and PDF) we found three diagnostic...

  14. Two eclipsing ultraluminous X-ray sources in M 51

    CERN Document Server

    Urquhart, Ryan

    2016-01-01

    We present the discovery, from archival Chandra and XMM-Newton data, of X-ray eclipses in two ultraluminous X-ray sources (ULXs), located in the same region of the galaxy M 51: CXOM51 J132940.0$+$471237 (ULX-1, for simplicity) and CXOM51 J132939.5$+$471244 (ULX-2). Three eclipses were detected for ULX-1, two for ULX-2. The presence of eclipses puts strong constraints on the viewing angle, suggesting that both ULXs are seen almost edge-on and are certainly not beamed towards us. Despite the similar viewing angles and luminosities ($L_{\\rm X} \\approx 2 \\times 10^{39}$ erg s$^{-1}$ in the $0.3$-$8$ keV band for both sources), their X-ray properties are different. ULX-1 has a soft spectrum, well fitted by Comptonization emission from a medium with electron temperature $kT_e \\approx 1$ keV. ULX-2 is harder, well fitted by a slim disk with $kT_{\\rm in} \\approx 1.5$-$1.8$ keV and normalization consistent with a $\\sim 10 M_{\\odot}$ black hole. ULX-1 has a significant contribution from multi-temperature thermal plasma...

  15. Matching microlensing events with X-ray sources

    CERN Document Server

    Sartore, N

    2011-01-01

    The detection of old neutron stars and black holes in isolation is one of the cornerstones of compact object astrophysics. Microlensing surveys may help on this purpose since the lensing mechanism is independent of the emission properties of the lens. Indeed, several black hole candidates deriving through microlensing observations have been reported in the literature. The identification of counterparts, especially in the X-rays, would be a strong argument in favor of the compact nature of these lenses. We perform a cross-correlation between the catalogs of microlensing events by the OGLE, MACHO and MOA teams, and those of X-rays sources from XMM-Newton and Chandra satellites. Based on our previous work, we select only microlensing events longer than 100 days, which should contain a large fraction of lenses as compact objects. Our matching criterion takes into account the positional coincidence in the sky. We find a single match between a microlensing event OGLE 2004-BLG-81 and the X-ray source 2XMM J180540.5-...

  16. Probing X-ray photoevaporative winds through their interaction with ionising radiation in cluster environments: the case for X-ray proplyds

    CERN Document Server

    Clarke, C J

    2014-01-01

    We show that if young low mass stars undergo vigorous X-ray driven disc winds, these may be detected in clusters through their interaction with ionising radiation from massive stars. We argue that in the ONC (Orion Nebula Cluster) one should see $\\sim$ 10s of `X-ray proplyds' ( objects with optically imaged offset ionisation fronts) in the range $0.3-0.6$pc from $\\theta_1$C Ori (the dominant O star in the ONC). Such objects lie outside the central `FUV zone' in the ONC where proplyds are instead well explained by neutral winds driven by external Far Ultraviolet (FUV) emission from $\\theta_1$C. We show that the predicted numbers and sizes of X-ray proplyds are compatible with those observed and that this may also explain at least some of the far flung proplyds seen in the Carina nebula. We compare the sizes of observed proplyds outside the FUV region of the ONC with model predictions based on the current observed X-ray luminosities of these sources ( bearing in mind that the current size is actually set by the...

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

    CERN Document Server

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

    2004-01-01

    We present optical integral field observations of the H II region containing the ultraluminous X-ray source Holmberg II X-1. We confirm the existence of an X-ray ionized nebula as the counterpart of the source due to the detection of an extended He II (4686A) region (21 x 47 pc) at the Chandra ACIS-S position. An extended blue objects with a size of 11 x 14 pc is coincident with the X-ray/He II region, which could indicate either a young stellar complex or a cluster. We have derived an X-ray to optical luminosity ratio of Lx/Lb>170, and presumable it is Lx/Lb~300-400 using the recent HST ACS data. We find a complex velocity dispersion at the position of the ULX. In addition, there is a radial velocity variation in the X-ray ionized region found in the He II emission of +-50 km/s on spatial scales of 2-3 arcsec. We believe that the putative black hole not only ionizes the surrounding HII gas, but also perturbs it dynamically (via jets or the accretion disk wind). The spatial analysis of the public Chandra ACIS...

  18. Deterministic Chaos in the X-ray Sources

    Science.gov (United States)

    Grzedzielski, M.; Sukova, P.; Janiuk, A.

    2015-12-01

    Hardly any of the observed black hole accretion disks in X-ray binaries and active galaxies shows constant flux. When the local stochastic variations of the disk occur at specific regions where a resonant behaviour takes place, there appear the quasi-periodic oscillations (QPOs). If the global structure of the flow and its non-linear hydrodynamics affects the fluctuations, the variability is chaotic in the sense of deterministic chaos. Our aim is to solve a problem of the stochastic versus deterministic nature of the black hole binary variabilities. We use both observational and analytic methods. We use the recurrence analysis and we study the occurence of long diagonal lines in the recurrence plot of observed data series and compare it to the surrogate series. We analyze here the data of two X-ray binaries - XTE J1550-564 and GX 339-4 observed by Rossi X-ray Timing Explorer. In these sources, the non-linear variability is expected because of the global conditions (such as the mean accretion rate) leading to the possible instability of an accretion disk. The thermal-viscous instability and fluctuations around the fixed-point solution occurs at high accretion rate, when the radiation pressure gives dominant contribution to the stress tensor.

  19. Deterministic chaos in the X-Ray sources

    CERN Document Server

    Grzedzielski, M; Janiuk, A

    2015-01-01

    Hardly any of the observed black hole accretion disks in X-Ray binaries and active galaxies shows constant flux. When the local stochastic variations of the disk occur at specific regions where a resonant behaviour takes place, there appear the Quasi-Periodic Oscillations (QPOs). If the global structure of the flow and its non-linear hydrodynamics affects the fluctuations, the variability is chaotic in the sense of deterministic chaos. Our aim is to solve a problem of the stochastic versus deterministic nature of the black hole binaries vari- ability. We use both observational and analytic methods. We use the recurrence analysis and we study the occurence of long diagonal lines in the recurrence plot of observed data series and compare it to the sur- rogate series. We analyze here the data of two X-Ray binaries - XTE J1550-564, and GX 339-4 observed by Rossi X-ray Timing Explorer. In these sources, the non-linear variability is expected because of the global conditions (such as the mean accretion rate) leadin...

  20. Deterministic Chaos in the X-ray Sources

    Indian Academy of Sciences (India)

    M. Grzedzielski; P. Sukova; A. Janiuk

    2015-12-01

    Hardly any of the observed black hole accretion disks in X-ray binaries and active galaxies shows constant flux. When the local stochastic variations of the disk occur at specific regions where a resonant behaviour takes place, there appear the quasi-periodic oscillations (QPOs). If the global structure of the flow and its non-linear hydrodynamics affects the fluctuations, the variability is chaotic in the sense of deterministic chaos. Our aim is to solve a problem of the stochastic versus deterministic nature of the black hole binary variabilities. We use both observational and analytic methods. We use the recurrence analysis and we study the occurence of long diagonal lines in the recurrence plot of observed data series and compare it to the surrogate series. We analyze here the data of two X-ray binaries – XTE J1550-564 and GX 339-4 observed by Rossi X-ray Timing Explorer. In these sources, the non-linear variability is expected because of the global conditions (such as the mean accretion rate) leading to the possible instability of an accretion disk. The thermal-viscous instability and fluctuations around the fixedpoint solution occurs at high accretion rate, when the radiation pressure gives dominant contribution to the stress tensor.

  1. Compact X-ray source based on Compton backscattering

    CERN Document Server

    Bulyak, E V; Zelinsky, A; Karnaukhov, I; Kononenko, S; Lapshin, V G; Mytsykov, A; Telegin, Yu P; Khodyachikh, A; Shcherbakov, A; Molodkin, V; Nemoshkalenko, V; Shpak, A

    2002-01-01

    The feasibility study of an intense X-ray source based on the interaction between the electron beam in a compact storage ring and the laser pulse accumulated in an optical resonator is carried out. We propose to reconstruct the 160 MeV electron storage ring N-100, which was shutdown several years ago. A new magnetic lattice will provide a transverse of electron beam size of approx 35 mu m at the point of electron beam-laser beam interaction. The proposed facility is to generate X-ray beams of intensity approx 2.6x10 sup 1 sup 4 s sup - sup 1 and spectral brightness approx 10 sup 1 sup 2 phot/0.1%bw/s/mm sup 2 /mrad sup 2 in the energy range from 10 keV up to 0.5 MeV. These X-ray beam parameters meet the requirements for most of technological and scientific applications. Besides, we plan to use the new facility for studying the laser cooling effect.

  2. The X-ray luminosity function of low mass X-ray binaries in early-type galaxies, their metal-rich, and metal-poor globular clusters

    CERN Document Server

    Peacock, Mark B

    2015-01-01

    We present the X-ray luminosity function (XLF) of low mass X-ray binaries (LMXBs) in the globular clusters (GCs) and fields of seven early-types galaxies. These galaxies are selected to have both deep Chandra observations, which allow their LMXB populations to be observed to X-ray luminosities of $10^{37}-10^{38}$ erg/s, and HST optical mosaics which enable the X-ray sources to be separated into field LMXBs, GC LMXBs, and contaminating background and foreground sources. We find that at all luminosities the number of field LMXBs per stellar mass is similar in these galaxies. This suggests that the field LMXB populations in these galaxies are not effected by the GC specific frequency, and that properties such as binary fraction and the stellar initial mass function are either similar across the sample, or change in a way that does not effect the number of LMXBs. We compare the XLF of the field LMXBs to that of the GC LMXBs and find that they are significantly different with a p-value of $3\\times10^{-6}$ (equiva...

  3. Properties and Applications of Laser Generated X-Ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R F; Key, M H

    2002-02-25

    The rapid development of laser technology and related progress in research using lasers is shifting the boundaries where laser based sources are preferred over other light sources particularly in the XUV and x-ray spectral region. Laser based sources have exceptional capability for short pulse and high brightness and with improvements in high repetition rate pulsed operation, such sources are also becoming more interesting for their average power capability. This study presents an evaluation of the current capabilities and near term future potential of laser based light sources and summarizes, for the purpose of comparison, the characteristics and near term prospects of sources based on synchrotron radiation and free electron lasers. Conclusions are drawn on areas where the development of laser based sources is most promising and competitive in terms of applications potential.

  4. Fossil Group Origins. VI. Global X-ray scaling relations of fossil galaxy clusters

    CERN Document Server

    Kundert, A; D'Onghia, E; Girardi, M; Aguerri, J A L; Barrena, R; Corsini, E M; De Grandi, S; Jiménez-Bailón, E; Lozada-Muñoz, M; Méndez-Abreu, J; Sánchez-Janssen, R; Wilcots, E; Zarattini, S

    2015-01-01

    We present the first pointed X-ray observations of ten candidate fossil galaxy groups and clusters. With these Suzaku observations, we determine global temperatures and bolometric X-ray luminosities of the intracluster medium (ICM) out to $r_{500}$ for six systems in our sample. The remaining four systems show signs of significant contamination from non-ICM sources. For the six objects with successfully determined $r_{500}$ properties, we measure global temperatures between $2.8 \\ \\mathrm{keV} \\leq T_{\\mathrm{X}} \\leq 5.3 \\ \\mathrm{keV}$, bolometric X-ray luminosities of $0.6 \\times 10^{44} \\ \\mathrm{ergs} \\ \\mathrm{s}^{-1} \\leq L_{\\mathrm{X,bol}} \\leq 7.2\\times 10^{44} \\ \\mathrm{ergs} \\ \\mathrm{s}^{-1}$, and estimate masses, as derived from $T_{\\mathrm{X}}$, of $M_{500} \\gtrsim 10^{14} \\ \\mathrm{M}_{\\odot}$. Scaling relations are constructed for an assembled sample of fossil and non-fossil systems using global X-ray luminosities, temperatures, optical luminosities, and velocity dispersions. The fit of the sc...

  5. The X-ray globular cluster NGC 1851

    CERN Document Server

    Alcaino, G

    1976-01-01

    A BV photometric investigation of the Southern Globular Cluster NGC 1851, was carried out using the 1 m telescope of Cerro La Silla (ESO) for the photoelectric work and the 1 m telescope of Cerro Las Campanas (CARSO) for the photographic work. Nineteen stars were observed photoelectrically, the limiting magnitude being V=16.18. Using this sequence, 156 stars were measured photographically. The derived apparent distance modulus is (m-M)/sub app/=15/sup m/.50. The reddening is E(B-V)=0/sup m/.10. The true distance modulus is (m-M) /sub 0/=15/sup m/.20. The distance is 11 kpc from the sun, 6 kpc from the galactic plane and 17 kpc from the galactic centre. The main features of the colour-magnitude diagram are: a well defined horizontal branch abundant in red stars and deficient in blue stars, a rich subgiant and asymptotic branch and a moderately populated red giant branch of medium steepness rising to Delta V=2/sup m/.5 at (B-V) /sub 0/=1.4. At the distance of 11 kpc the maximum observed luminosity of the X-ray ...

  6. A Machine-learning approach to classification of X-ray sources

    Science.gov (United States)

    Hare, Jeremy; Kargaltsev, Oleg; Rangelov, Blagoy; Pavlov, George; Posselt, Bettina; Volkov, Igor

    2017-08-01

    Chandra and XMM-Newton X-ray observatories have serendipitously detected a large number of Galactic sources. Although their properties are automatically extracted and stored in catalogs, most of these sources remain unexplored. Classifying these sources can enable population studies on much larger scales and may also reveal new types of X-ray sources. For most of these sources the X-ray data alone are not enough to identify their nature, and multiwavelength data must be used. We developed a multiwavelength classification pipeline (MUWCLASS), which relies on supervised machine learning and a rich training dataset. We describe the training dataset, the pipeline and its testing, and will show/discuss how the code performs in different example environments, such as unidentified gamma-ray sources, supernova remnants, dwarf galaxies, stellar clusters, and the inner Galactic plane. We also discuss the application of this approach to the data from upcoming new X-ray observatories (e.g., eROSITA, Athena).

  7. Enrichment study of hot intra-cluster gas through X-ray spectroscopy

    NARCIS (Netherlands)

    Plaa, J. de

    2007-01-01

    Enrichment study of hot intra-cluster gas through X-ray spectroscopy Clouds of hot X-ray emitting gas associated with clusters of galaxies are the biggest aggregates of baryons that we know, except for the cosmic web. A typical cloud contains the nuclear-fusion products of billions of supernovae. Th

  8. The Intracluster Gas Fraction in X-ray Clusters Constraints on the Clustered Mass Density

    CERN Document Server

    Evrard, A E

    1997-01-01

    The mean intracluster gas fraction of X-ray clusters within their hydrostatic regions is derived from recent observational compilations of David, Jones & Forman and White & Fabian. At radii encompassing a mean density 500 times the critical value, the individual sample bi-weight means are moderately ($2.4 by numerical simulations removes the discrepancy and results in a combined sample mean and standard error $\\fbargas(r_{500}) = (0.060 \\pm 0.003) assumption to maximize cluster gas content, this value constrains the universal ratio of total, clustered to baryonic mass $\\Omega_m/\\Omega_b \\le 23.1 physically plausible approach based on low D/H inferences from quasar absorption spectra and accounting for baryons within cluster galaxies yields an estimate $Ømega_m \\h^{2/3} = 0.28 \\pm 0.07$ with sources of systematic error involved in the derivation providing approximately $35%$ uncertainty. Additional effects which could provide consistency with the Einstein-deSitter case $Ømega_m \\se 1$ are presented, ...

  9. Joint signal extraction from galaxy clusters in X-ray and SZ surveys: A matched-filter approach

    Science.gov (United States)

    Tarrío, P.; Melin, J.-B.; Arnaud, M.; Pratt, G. W.

    2016-06-01

    The hot ionized gas of the intra-cluster medium emits thermal radiation in the X-ray band and also distorts the cosmic microwave radiation through the Sunyaev-Zel'dovich (SZ) effect. Combining these two complementary sources of information through innovative techniques can therefore potentially improve the cluster detection rate when compared to using only one of the probes. Our aim is to build such a joint X-ray-SZ analysis tool, which will allow us to detect fainter or more distant clusters while maintaining high catalogue purity. We present a method based on matched multifrequency filters (MMF) for extracting cluster catalogues from SZ and X-ray surveys. We first designed an X-ray matched-filter method, analogous to the classical MMF developed for SZ observations. Then, we built our joint X-ray-SZ algorithm by combining our X-ray matched filter with the classical SZ-MMF, for which we used the physical relation between SZ and X-ray observations. We show that the proposed X-ray matched filter provides correct photometry results, and that the joint matched filter also provides correct photometry when the FX/Y500 relation of the clusters is known. Moreover, the proposed joint algorithm provides a better signal-to-noise ratio than single-map extractions, which improves the detection rate even if we do not exactly know the FX/Y500 relation. The proposed methods were tested using data from the ROSAT all-sky survey and from the Planck survey.

  10. OPTICAL AND X-RAY PROPERTIES OF GALAXY CLUSTERS AT INTERMEDIATE RESHIFTS

    Directory of Open Access Journals (Sweden)

    E. R. Carrasco

    2009-01-01

    Full Text Available We analyze the cluster properties and investigate the galaxy population of a sample of low-luminosity X-ray galaxy clusters at intermediate redshifts (z = 0:2-0:5. The study is based on deep imaging and spectroscopic observations and X-ray archival data. We discuss in detail the global cluster properties and galaxy content based on the analysis of the velocity distribution, the galaxy projected distribution, the cluster color-magnitude diagram, and the study of the mass distribution, based on weak lensing and X-ray emission, for one of the cluster located at z = 0:485.

  11. Automatic classification of time-variable X-ray sources

    CERN Document Server

    Lo, Kitty K; Murphy, Tara; Gaensler, B M

    2014-01-01

    To maximize the discovery potential of future synoptic surveys, especially in the field of transient science, it will be necessary to use automatic classification to identify some of the astronomical sources. The data mining technique of supervised classification is suitable for this problem. Here, we present a supervised learning method to automatically classify variable X-ray sources in the second \\textit{XMM-Newton} serendipitous source catalog (2XMMi-DR2). Random Forest is our classifier of choice since it is one of the most accurate learning algorithms available. Our training set consists of 873 variable sources and their features are derived from time series, spectra, and other multi-wavelength contextual information. The 10-fold cross validation accuracy of the training data is ${\\sim}$97% on a seven-class data set. We applied the trained classification model to 411 unknown variable 2XMM sources to produce a probabilistically classified catalog. Using the classification margin and the Random Forest der...

  12. Flat Field Anomalies in an X-ray CCD Camera Measured Using a Manson X-ray Source

    Energy Technology Data Exchange (ETDEWEB)

    M. J. Haugh and M. B. Schneider

    2008-10-31

    The Static X-ray Imager (SXI) is a diagnostic used at the National Ignition Facility (NIF) to measure the position of the X-rays produced by lasers hitting a gold foil target. The intensity distribution taken by the SXI camera during a NIF shot is used to determine how accurately NIF can aim laser beams. This is critical to proper NIF operation. Imagers are located at the top and the bottom of the NIF target chamber. The CCD chip is an X-ray sensitive silicon sensor, with a large format array (2k x 2k), 24 μm square pixels, and 15 μm thick. A multi-anode Manson X-ray source, operating up to 10kV and 10W, was used to characterize and calibrate the imagers. The output beam is heavily filtered to narrow the spectral beam width, giving a typical resolution E/ΔE≈10. The X-ray beam intensity was measured using an absolute photodiode that has accuracy better than 1% up to the Si K edge and better than 5% at higher energies. The X-ray beam provides full CCD illumination and is flat, within ±1% maximum to minimum. The spectral efficiency was measured at 10 energy bands ranging from 930 eV to 8470 eV. We observed an energy dependent pixel sensitivity variation that showed continuous change over a large portion of the CCD. The maximum sensitivity variation occurred at 8470 eV. The geometric pattern did not change at lower energies, but the maximum contrast decreased and was not observable below 4 keV. We were also able to observe debris, damage, and surface defects on the CCD chip. The Manson source is a powerful tool for characterizing the imaging errors of an X-ray CCD imager. These errors are quite different from those found in a visible CCD imager.

  13. THE X-RAY LUMINOSITY FUNCTION OF LOW MASS X-RAY BINARIES IN EARLY-TYPE GALAXIES, THEIR METAL-RICH, AND METAL-POOR GLOBULAR CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Peacock, Mark B.; Zepf, Stephen E., E-mail: mpeacock@msu.edu [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2016-02-10

    We present the X-ray luminosity function (XLF) of low-mass X-ray binaries (LMXBs) in the globular clusters (GCs) and fields of seven early-type galaxies. These galaxies are selected to have both deep Chandra observations, which allow their LMXB populations to be observed to X-ray luminosities of 10{sup 37}–10{sup 38} erg s{sup −1}, and Hubble Space Telescope optical mosaics that enable the X-ray sources to be separated into field LMXBs, GC LMXBs, and contaminating background and foreground sources. We find that at all luminosities the number of field LMXBs per stellar mass is similar in these galaxies. This suggests that the field LMXB populations in these galaxies are not effected by the GC specific frequency, and that properties such as binary fraction and the stellar initial mass function are either similar across the sample or change in a way that does not affect the number of LMXBs. We compare the XLF of the field LMXBs to that of the GC LMXBs and find that they are significantly different with a p-value of 3 × 10{sup −6} (equivalent to 4.7σ for a normal distribution). The difference is such that the XLF of the GC LMXBs is flatter than that of the field LMXBs, with the GCs hosting relatively more bright sources and fewer faint sources. A comparison of the XLF of the metal-rich and metal-poor GCs hints that the metal-poor clusters may have more bright LMXBs, but the difference is not statistically significant.

  14. Simulating the sensitivity to stellar point sources of Chandra X-ray observations

    CERN Document Server

    Wright, Nicholas J; Guarcello, Mario G; Kashyap, Vinay L; Zezas, Andreas

    2015-01-01

    The Chandra Cygnus OB2 Legacy Survey is a wide and deep X-ray survey of the nearby and massive Cygnus OB2 association. The survey has detected ~8,000 X-ray sources, the majority of which are pre-main sequence X-ray emitting young stars in the association itself. To facilitate quantitative scientific studies of these sources as well as the underlying OB association it is important to understand the sensitivity of the observations and the level of completeness the observations have obtained. Here we describe the use of a hierarchical Monte Carlo simulation to achieve this goal by combining the empirical properties of the observations, analytic estimates of the source verification process, and an extensive set of source detection simulations. We find that our survey reaches a 90% completeness level for a pre-main-sequence population at the distance of Cyg OB2 at an X-ray luminosity of 4 x 10^30 ergs/s and a stellar mass of 1.3 Msun for a randomly distributed population. For a spatially clustered population such ...

  15. A laser-driven undulator x-ray source: simulation of image formation and dose deposition in mammography

    Science.gov (United States)

    Müller, Bernhard; Schlattl, Helmut; Grüner, Florian; Hoeschen, Christoph

    2011-03-01

    Since overcoming some of the inherent limitations of x-ray tubes becomes increasingly harder, it is important to consider new ways of x-ray generation and to study their applications in the field of medical imaging. In the present work we investigate a novel table-top-sized x-ray source, developed in a joint project within the Cluster of Excellence "Munich Center for Advanced Photonics". It uses laser-accelerated electrons emitting x-ray radiation in a short period undulator. This source has the potential to deliver tunable x-rays with a very narrow spectral bandwidth. The main purpose of this contribution is to investigate the performance of this source in the field of mammography and to compare it to that of conventional x-ray tubes. We simulated the whole imaging process from the electron beam dynamics through the generation of the synchrotron radiation in the undulator up to the x-ray-matter interaction and detection in the mammographic setting. A Monte Carlo simulation of the absorption and scattering processes based on the Geant4 software toolkit has been developed that uses a high-resolution voxel phantom of the female breast for the accurate simulation of mammography. We present simulated mammograms generated by using quasi-monochromatic undulator radiation and by using the polychromatic spectrum of a conventional x-ray tube.

  16. X-ray and optical spectroscopy of the massive young open cluster IC 1805

    Science.gov (United States)

    Rauw, G.; Nazé, Y.

    2016-10-01

    Context. Very young open clusters are ideal places to study the X-ray properties of a homogeneous population of early-type stars. In this respect, the IC 1805 open cluster is very interesting as it hosts the O4 If+ star HD 15570 thought to be in an evolutionary stage intermediate between a normal O-star and a Wolf-Rayet star. Aims: Such a star could provide a test for theoretical models aiming at explaining the empirical scaling relation between the X-ray and bolometric luminosities of O-type stars. Methods: We have observed IC 1805 with XMM-Newton and further collected optical spectroscopy of some of the O-star members of the cluster. Results: The optical spectra allow us to revisit the orbital solutions of BD+60° 497 and HD 15558, and provide the first evidence of binarity for BD+60° 498. X-ray emission from colliding winds does not appear to play an important role among the O-stars of IC 1805. Notably, the X-ray fluxes do not vary significantly between archival X-ray observations and our XMM-Newton pointing. The very fast rotator BD+60° 513, and to a lesser extent the O4 If+ star HD 15570 appear somewhat underluminous. Whilst the underluminosity of HD 15570 is only marginally significant, its amplitude is found to be compatible with theoretical expectations based on its stellar and wind properties. A number of other X-ray sources are detected in the field, and the brightest objects, many of which are likely low-mass pre-main sequence stars, are analyzed in detail. Based on observations collected with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA), and with the TIGRE telescope (La Luz, Mexico).Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/594/A82

  17. A dozen colliding wind X-ray binaries in the star cluster R136 in the 30 Doradus region

    CERN Document Server

    Zwart, S P; Lewin, W H G; Zwart, Simon Portegies; Pooley, David; Lewin, Walter

    2002-01-01

    We analyzed archival Chandra X-ray observations of the central portion of the 30 Doradus region in the Large Magellanic Cloud. The image contains 20 X-ray point sources with luminosities between 5x10^32 and 2x10^35 erg/s (0.2 to 3.5 keV). A dozen sources have bright WN Wolf-Rayet or spectral type O stars as optical counterparts. Nine of these are within about 3.4pc of R136, the central star cluster of NGC2070. We derive an empirical relation between the X-ray luminosity and the parameters for the stellar wind of the optical counterpart. The relation gives good agreement for known colliding wind binaries in the Milky Way Galaxy and for the identified X-ray sources in NGC2070. We conclude that probably all identified X-ray sources in NGC2070 are colliding wind binaries and that they are not associated with compact objects. This conclusion contradicts Wang (1995) who argued, using ROSAT data, that two earlier discovered X-ray sources are accreting black-hole binaries. Five early type stars in R136 are not bright...

  18. Patchy Accretion Disks in Ultraluminous X-ray Sources

    CERN Document Server

    Miller, J M; Barret, D; Harrison, F A; Fabian, A C; Webb, N A; Walton, D J; Rana, V

    2014-01-01

    The X-ray spectra of the most extreme ultra-luminous X-ray sources -- those with L > 1 E+40 erg/s -- remain something of a mystery. Spectral roll-over in the 5-10 keV band was originally detected in in the deepest XMM-Newton observations of the brightest sources; this is confirmed in subsequent NuSTAR spectra. This emission can be modeled via Comptonization, but with low electron temperatures (kT_e ~ 2 keV) and high optical depths (tau ~ 10) that pose numerous difficulties. Moreover, evidence of cooler thermal emission that can be fit with thin disk models persists, even in fits to joint XMM-Newton and NuSTAR observations. Using NGC 1313 X-1 as a test case, we show that a patchy disk with a multiple temperature profile may provide an excellent description of such spectra. In principle, a number of patches within a cool disk might emit over a range of temperatures, but the data only require a two-temperature profile plus standard Comptonization, or three distinct blackbody components. A mechanism such as the p...

  19. Two-dimensional X-ray focusing by off-axis grazing incidence phase Fresnel zone plate on the laboratory X-ray source

    Science.gov (United States)

    Grigoriev, Maxim; Fakhrtdinov, Rashid; Irzhak, Dmitry; Firsov, Alexander; Firsov, Anatoly; Svintsov, Alexander; Erko, Alexey; Roshchupkin, Dmitry

    2017-02-01

    The results of studying a two-dimensional X-ray focusing by an off-axis grazing incidence phase Fresnel zone plate on the laboratory X-ray source are presented. This optics enables obtaining a focal spot of 2 μm on the laboratory X-ray source with a focusing efficiency of 30% at a high signal/noise ratio.

  20. Non-thermal X-ray Emission An Alternative to Cluster Cooling Flows?

    CERN Document Server

    McCarthy, I G; Welch, G A; Carthy, Ian G. Mc; West, Michael J.; Welch, Gary A.

    2002-01-01

    We report the results of experiments aimed at reducing the major problem with cooling flow models of rich cluster X-ray sources: the fact that most of the cooled gas or its products have not been found. Here we show that much of the X-ray emission usually attributed to cooling flows can, in fact, be modeled by a power-law component which is indicative of a source(s) other than thermal bremsstrahlung from the intracluster medium. We find that adequate simultaneous fits to ROSAT PSPCB and ASCA GIS/SIS spectra of the central regions of ten clusters are obtained for two-component models that include a thermal plasma component that is attributable to hot intracluster gas and a power-law component that is likely generated by compact sources and/or extended non-thermal emission. For five of the clusters that purportedly have massive cooling flows, the best-fit models have power-law components that contribute $\\sim$ 30 % of the total flux (0.14 - 10.0 keV) within the central 3 arcminutes. Because cooling flow mass de...

  1. X-ray Properties of Young Stars and Stellar Clusters

    CERN Document Server

    Feigelson, E; Güdel, M; Stassun, K G; Feigelson, Eric; Townsley, Leisa; Gudel, Manuel

    2006-01-01

    Although the environments of star and planet formation are thermodynamically cold, substantial X-ray emission from 10-100 MK plasmas is present. In low mass pre-main sequence stars, X-rays are produced by violent magnetic reconnection flares. In high mass O stars, they are produced by wind shocks on both stellar and parsec scales. The recent Chandra Orion Ultradeep Project, XMM-Newton Extended Survey of Taurus, and Chandra studies of more distant high-mass star forming regions reveal a wealth of X-ray phenomenology and astrophysics. X-ray flares mostly resemble solar-like magnetic activity from multipolar surface fields, although extreme flares may arise in field lines extending to the protoplanetary disk. Accretion plays a secondary role. Fluorescent iron line emission and absorption in inclined disks demonstrate that X-rays can efficiently illuminate disk material. The consequent ionization of disk gas and irradiation of disk solids addresses a variety of important astrophysical issues of disk dynamics, pla...

  2. Modification of the TASMIP x-ray spectral model for the simulation of microfocus x-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Sisniega, A.; Vaquero, J. J., E-mail: juanjose.vaquero@uc3m.es [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain); Instituto de Investigación Sanitaria Gregorio Marañón, Madrid ES28007 (Spain); Desco, M. [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain); Instituto de Investigación Sanitaria Gregorio Marañón, Madrid ES28007 (Spain); Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid ES28029 (Spain)

    2014-01-15

    Purpose: The availability of accurate and simple models for the estimation of x-ray spectra is of great importance for system simulation, optimization, or inclusion of photon energy information into data processing. There is a variety of publicly available tools for estimation of x-ray spectra in radiology and mammography. However, most of these models cannot be used directly for modeling microfocus x-ray sources due to differences in inherent filtration, energy range and/or anode material. For this reason the authors propose in this work a new model for the simulation of microfocus spectra based on existing models for mammography and radiology, modified to compensate for the effects of inherent filtration and energy range. Methods: The authors used the radiology and mammography versions of an existing empirical model [tungsten anode spectral model interpolating polynomials (TASMIP)] as the basis of the microfocus model. First, the authors estimated the inherent filtration included in the radiology model by comparing the shape of the spectra with spectra from the mammography model. Afterwards, the authors built a unified spectra dataset by combining both models and, finally, they estimated the parameters of the new version of TASMIP for microfocus sources by calibrating against experimental exposure data from a microfocus x-ray source. The model was validated by comparing estimated and experimental exposure and attenuation data for different attenuating materials and x-ray beam peak energy values, using two different x-ray tubes. Results: Inherent filtration for the radiology spectra from TASMIP was found to be equivalent to 1.68 mm Al, as compared to spectra obtained from the mammography model. To match the experimentally measured exposure data the combined dataset required to apply a negative filtration of about 0.21 mm Al and an anode roughness of 0.003 mm W. The validation of the model against real acquired data showed errors in exposure and attenuation in

  3. The Connection Between X-ray Binaries and Star Clusters in NGC 4449

    CERN Document Server

    Rangelov, Blagoy; Chandar, Rupali

    2011-01-01

    We present 23 candidate X-ray binaries with luminosities down to 1.8x10^36 erg/s, in the nearby starburst galaxy NGC 4449, from observations totaling 105 ksec taken with the ACIS-S instrument on the Chandra Space Telescope. We determine count rates, luminosities, and colors for each source, and perform spectral fits for sources with sufficient counts. We also compile a new catalog of 129 compact star clusters in NGC 4449 from high resolution, multi-band optical images taken with the Hubble Space Telescope, doubling the number of clusters known in this galaxy. The UBVI,Ha luminosities of each cluster are compared with predictions from stellar evolution models to estimate their ages and masses. We find strong evidence for a population of very young massive, black-hole binaries, which comprise nearly 50% of the detected X-ray binaries in NGC 4449. Approximately a third of these remain within their parent star clusters, which formed t < 6-8 Myr ago, while others have likely been ejected from their parent clust...

  4. LIGHT SOURCE: Spot size diagnostics for flash radiographic X-ray sources at LAPA

    Science.gov (United States)

    Li, Cheng-Gang; Li, Qin; Shi, Jin-Shui; Deng, Jian-Jun

    2009-06-01

    Spot size is one of the parameters to characterize the performance of a radiographic X-ray source. It determines the degree of blurring due to magnification directly. In recent years, a variety of measurement methods have been used to diagnose X-ray spot size at Laboratory of Accelerator Physics and Application (LAPA). Computer simulations and experiments showed that using a rolled-edge to measure the spot size are more accurate, and the intensity distribution of X-ray source was obtained by a device with a square aperture. Experimental and simulation results on a flash X-ray source at our laboratory are presented and discussed in this paper. In addition, a new method for time resolved diagnostics of X-ray spot size is introduced too.

  5. The WARPS Survey. VIII. Evolution of the Galaxy Cluster X-ray Luminosity Function

    CERN Document Server

    Koens, L A; Jones, L R; Ebeling, H; Horner, D J; Perlman, E S; Phillipps, S; Scharf, C A

    2012-01-01

    We present measurements of the galaxy cluster X-ray Luminosity Function (XLF) from the Wide Angle ROSAT Pointed Survey (WARPS) and quantify its evolution. WARPS is a serendipitous survey of the central region of ROSAT pointed observations and was carried out in two phases (WARPS-I and WARPS-II). The results here are based on a final sample of 124 clusters, complete above a flux limit of 6.5 10E-15 erg/s/cm2, with members out to redshift z ~ 1.05, and a sky coverage of 70.9 deg2. We find significant evidence for negative evolution of the XLF, which complements the majority of X-ray cluster surveys. To quantify the suggested evolution, we perform a maximum likelihood analysis and conclude that the evolution is driven by a decreasing number density of high luminosity clusters with redshift, while the bulk of the cluster population remains nearly unchanged out to redshift z ~ 1.1, as expected in a low density Universe. The results are found to be insensitive to a variety of sources of systematic uncertainty that ...

  6. Carbon nanotube based X-ray sources: Applications in pre-clinical and medical imaging

    Science.gov (United States)

    Lee, Yueh Z.; Burk, Laurel; Wang, Ko-Han; Cao, Guohua; Lu, Jianping; Zhou, Otto

    2011-08-01

    Field emission offers an alternate method of electron production for Bremsstrahlung based X-ray tubes. Carbon nanotubes (CNTs) serve as very effective field emitters, allowing them to serve as electron sources for X-ray sources, with specific advantages over traditional thermionic tubes. CNT derived X-ray sources can create X-ray pulses of any duration and frequency, gate the X-ray pulse to any source and allow the placement of many sources in close proximity.We have constructed a number of micro-CT systems based on CNT X-ray sources for applications in small animal imaging, specifically focused on the imaging of the heart and lungs. This paper offers a review of the pre-clinical applications of the CNT based micro-CT that we have developed. We also discuss some of the current and potential clinical applications of the CNT X-ray sources.

  7. Chilled disks in ultraluminous X-ray sources

    Science.gov (United States)

    Soria, Roberto; Kuncic, Zdenka; Gonçalves, Anabela C.

    2007-04-01

    The "soft-excess" component fitted to the X-ray spectra of many ultraluminous X-ray sources (ULXs) remains a controversial finding, which may reveal fundamental information either on the black hole (BH) mass or on the state of the accretion flow. In the simplest model, it was explained as thermal emission from a cool accretion disk around an intermediate-mass BH (about 1000 solar masses). We argue that this scenario is highly implausible, and discuss and compare the two most likely alternatives. 1) The soft-excess does come from a cool disk; however, the temperature is low not because of a high BH mass but because most of the accretion power is drained from the inner disk via magnetic torques, and channelled into jets and outflows ("chilled disk" scenario). Using a phenomenological model, we infer that ULXs contain BHs of about 50 solar masses accreting gas at about 10 times their Eddington rate. 2) The soft excess is in fact a soft deficit, if the power-law continuum is properly fitted. Such broad absorption features are caused by smeared absorption lines in fast, highly ionized outflows. This scenario has already been successfully applied to the soft excess in AGN. If so, this spectral feature reveals details of disk outflows,but is unrelated to the BH mass.

  8. X-ray detectors at the Linac Coherent Light Source.

    Science.gov (United States)

    Blaj, Gabriel; Caragiulo, Pietro; Carini, Gabriella; Carron, Sebastian; Dragone, Angelo; Freytag, Dietrich; Haller, Gunther; Hart, Philip; Hasi, Jasmine; Herbst, Ryan; Herrmann, Sven; Kenney, Chris; Markovic, Bojan; Nishimura, Kurtis; Osier, Shawn; Pines, Jack; Reese, Benjamin; Segal, Julie; Tomada, Astrid; Weaver, Matt

    2015-05-01

    Free-electron lasers (FELs) present new challenges for camera development compared with conventional light sources. At SLAC a variety of technologies are being used to match the demands of the Linac Coherent Light Source (LCLS) and to support a wide range of scientific applications. In this paper an overview of X-ray detector design requirements at FELs is presented and the various cameras in use at SLAC are described for the benefit of users planning experiments or analysts looking at data. Features and operation of the CSPAD camera, which is currently deployed at LCLS, are discussed, and the ePix family, a new generation of cameras under development at SLAC, is introduced.

  9. X-ray emission from open star clusters with Spectrum-Rontgen-Gamma

    DEFF Research Database (Denmark)

    Singh, K.P.; Ojha, D.K.; Schnopper, H.W.;

    1998-01-01

    throughput of SPECTRUM-Rontgen-Gamma will help detect main sequence stars like Sun in middle-aged and old clusters. We will study the relationships between various parameters - age, rotation, abundance, UBV colors, X-ray luminosity, coronal temperature etc. X-ray spectra of younger and brighter populations...

  10. The K-band Hubble diagram for brightest cluster galaxies in X-ray clusters

    CERN Document Server

    Collins, C; Collins, Chris; Mann, Bob

    1997-01-01

    This paper concerns the K band Hubble diagram for the brightest cluster galaxies (BCGs) in a sample of X-ray clusters covering the redshift range $0.05 2.3 \\times 10^{44}$ erg s$^{-1}$ (in the 0.3 - 3.5 keV band) is no more than 0.22 mag, and is not significantly reduced by correcting for the BCG structure parameter, $\\alpha$, or for X-ray luminosity. This is the smallest scatter in the absolute magnitudes of any single class of galaxy and demonstrates the homogeneity of BCGs in high-$L_{\\rm X}$ clusters. By contrast, we find that the brightest members of low-$L_{\\rm X}$ systems display a wider dispersion ($\\sim 0.5$ mag) in absolute magnitude than commonly seen in previous studies, which arises from the inclusion, in X-ray flux-limited samples, of poor clusters and groups which are usually omitted from low redshift studies of BCGs in optically rich clusters....[abstract shortened].. The BCGs in our high-$L_{\\rm X}$ clusters yield a value of $\\Omega_{\\rm M}=0.28\\pm0.24$ if the cosmological constant with a 95 ...

  11. A systematic search for X-ray cavities in galaxy clusters, groups, and elliptical galaxies

    CERN Document Server

    Shin, Jaejin; Mulchaey, John S

    2016-01-01

    We perform a comprehensive study of X-ray cavities using a large sample of X-ray targets selected from the Chandra archive. The sample is selected to cover a large dynamic range including galaxy clusters, groups, and individual galaxies. Using $\\beta$-modeling and unsharp masking techniques, we investigate the presence of X-ray cavities for 133 targets that have sufficient X-ray photons for analysis. We detect 148 X-ray cavities from 69 targets and measure their properties, including cavity size, angle, and distance from the center of the diffuse X-ray gas. We confirm the strong correlation between cavity size and distance from the X-ray center similar to previous studies (i.e., Birzan et al. 2004; Diehl et al. 2008; Dong et al. 2010). We find that the detection rates of X-ray cavities are similar among galaxy clusters, groups and individual galaxies, suggesting that the formation mechanism of X-ray cavities is independent of environment.

  12. The X-ray Properties of Optically Selected Clusters of Galaxies

    CERN Document Server

    Hicks, Amalia K; Donahue, Megan; Ellingson, Erica; Gladders, Michael; Bohringer, Hans; Yee, Howard K C; Yan, Renbin; Croston, Judith H; Gilbank, David G

    2013-01-01

    We present the results of Chandra and Suzaku X-ray observations of nine moderate-redshift (0.16 < z < 0.42) clusters discovered via the Red-sequence Cluster Survey (RCS). Surface brightness profiles are fitted to beta models, gas masses are determined, integrated spectra are extracted within R2500, and X-ray temperatures and luminosities are inferred. The Lx-Tx relationship expected from self-similar evolution is tested by comparing this sample to our previous X-ray investigation of nine high-redshift (0.6 < z < 1.0) optically selected clusters. We find that optically selected clusters are systematically less luminous than X-ray selected clusters of similar X-ray temperature at both moderate and high-z. We are unable to constrain evolution in the Lx-Tx relation with these data, but find it consistent with no evolution, within relatively large uncertainties. To investigate selection effects, we compare the X-ray properties of our sample to those of clusters in the representative X-ray selected REXC...

  13. Statistics and implications of substructure detected in a representative sample of X-ray clusters

    CERN Document Server

    Chon, Gayoung; Smith, Graham

    2012-01-01

    We present a morphological study of 35 X-ray luminous galaxy clusters at 0.15Cluster Substructure Survey (LoCuSS), for which deep XMM-Newton observations are available. We characterise the structure of the X-ray surface brightness distribution of each cluster by measuring both their power ratios and centroid shift, and thus rank the clusters by the degree of substructure. These complementary probes give a consistent description of the cluster morphologies with some well understood exceptions. We find a remarkably tight correlation of regular morphology with the occurrence of cool cores in clusters. We also compare our measurements of X-ray morphology with measurements of the luminosity gap statistics and ellipticity of the brightest cluster galaxy (BCG). We check how our new X-ray morphological analysis maps onto cluster scaling relations, finding that (i) clusters with relatively undisturbed X-ray morphologies are on average more luminous at fixed X-ray...

  14. X-ray emission as a diagnostic from pseudospark-sourced electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Bowes, D., E-mail: david.bowes@strath.ac.uk [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Yin, H.; He, W.; Zhang, L.; Cross, A.W.; Ronald, K.; Phelps, A.D.R. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Chen, D.; Zhang, P. [Computed Tomography Lab, School of Mathematical Sciences, Capital Normal University, Beijing 100048 (China); Chen, X.; Li, D. [Department of Electronic Engineering, Queen Mary University of London, London E1 4NS (United Kingdom)

    2014-09-15

    X-ray emission has been achieved using an electron beam generated by a pseudospark low-pressure discharge and utilised as a diagnostic for beam detection. A 300 A, 34 kV PS-sourced electron beam pulse of 3 mm diameter impacting on a 0.1 mm-thick molybdenum target generated X-rays which were detected via the use of a small, portable X-ray detector. Clear X-ray images of a micro-sized object were captured using an X-ray photodetector. This demonstrates the inducement of proton induced X-ray emission (PIXE) not only as an indicator of beam presence but also as a future X-ray source for small-spot X-ray imaging of materials.

  15. A First Look at the X-ray Population of the Young Massive Cluster VVV CL077

    CERN Document Server

    Bodaghee, Arash; Fornasini, Francesca; Rahoui, Farid; Bauer, Franz E

    2015-01-01

    Multi-wavelength analysis of the young massive cluster VVV CL077 is presented for the first time. Our Chandra survey of this region enabled the detection of three X-ray emitting stellar members of the cluster, as well as a possible diffuse X-ray component that extends a few arcseconds from the cluster core with an intrinsic flux of (9+/-3)x10^-14 erg cm^-2 s^-1 in the 0.5-10 keV band. Infrared spectra we obtained for two of these X-ray point sources show absorption lines typical of the atmospheres of massive O stars. The X-ray spectrum from the visible extent of VVV CL077 i.e., a 15"-radius around the cluster, can be modeled with an absorbed power law with nH = (6+/-4)x10^22 cm^-2 and gamma = 2+/-1. In addition, the X-ray core of VVV CL077 coincides with diffuse emission seen in the infrared band and with a local maximum in the radio continuum map. A possible association with a neighboring H II region would place VVV CL077 at a distance of around 11 kpc; on the far side of the Norma Arm. At this distance, the...

  16. Synchrotron x-ray sources and new opportunities in the soil and environmental sciences

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, D. (Purdue Univ., Lafayette, IN (USA)); Anderson, S. (Michigan State Univ., East Lansing, MI (USA)); Mattigod, S. (Pacific Northwest Lab., Richland, WA (USA))

    1990-07-01

    This report contains the following papers: characteristics of the advanced photon source and comparison with existing synchrotron facilities; x-ray absorption spectroscopy: EXAFS and XANES -- A versatile tool to study the atomic and electronic structure of materials; applications of x-ray spectroscopy and anomalous scattering experiments in the soil and environmental sciences; X-ray fluorescence microprobe and microtomography.

  17. Comparison of the spatial and the angular clustering of X-ray AGN

    CERN Document Server

    Koutoulidis, L; Georgantopoulos, I; Georgakakis, A; Akylas, A; Basilakos, S; Mountrichas, G

    2016-01-01

    The angular correlation function is a powerful tool for deriving the clustering properties of AGN and hence the mass of the corresponding dark matter halos in which they reside. However, studies based on the application of the angular correlation function on X-ray samples, yield results apparently inconsistent with those based on the direct estimation of the spatial correlation function. The goal of the present paper is to attempt to investigate this issue by analysing a well defined sample. To this end we use the hard-band (2-10 keV) X-ray selected sources of the Chandra AEGIS fields, chosen because of the availability of accurately derived flux sensitivity maps. In particular we use the 186 hard-band sources with spectroscopic redshifts in the range z=0.3-1.3, a range selected in order to contain the bulk of the AGN while minimizing the contribution of unknown clustering and luminosity evolution from very high redshifts. Using the projected spatial auto-correlation function, we derive a clustering comoving ...

  18. AEGIS: The Clustering of X-ray AGN Relative to Galaxies at z~1

    CERN Document Server

    Coil, Alison L; Newman, Jeffrey A; Cooper, Michael C; Croton, Darren; Davis, Marc; Koo, David C; Laird, E S; Nandra, K; Weiner, Benjamin J; Willmer, Christopher N A; Yan, Renbin

    2009-01-01

    We measure the clustering of non-quasar X-ray AGN at z=0.7-1.4 in the AEGIS field. Using the cross-correlation of 113 Chandra-selected AGN, with a median log L_X=42.8 erg s^-1, with ~5,000 DEEP2 galaxies, we find that the X-ray AGN are fit by a power law with a clustering scale length of r_0=5.95 +/-0.90 h^-1 Mpc and slope gamma=1.66 +/-0.22. X-ray AGN have a similar clustering amplitude as red, quiescent and `green' transition galaxies at z~1 and are significantly more clustered than blue, star-forming galaxies. The X-ray AGN clustering strength is primarily determined by the host galaxy color; AGN in red host galaxies are significantly more clustered than AGN in blue host galaxies, with a relative bias that is similar to that of red to blue DEEP2 galaxies. We detect no dependence of clustering on optical brightness, X-ray luminosity, or hardness ratio within the ranges probed here. We find evidence for galaxies hosting X-ray AGN to be more clustered than a sample of galaxies with matching joint optical colo...

  19. Optical studies of the ultraluminous X-ray source NGC1313 X-2

    CERN Document Server

    Liu, J; Miller, J; Kaaret, Philip; Liu, Jifeng; Bregman, Joel; Miller, Jon; Kaaret, Philip

    2007-01-01

    NGC1313 X-2 was among the first ultraluminous X-ray sources discovered, and has been a frequent target of X-ray and optical observations. Using the HST/ACS multi-band observations, this source is identified with a unique counterpart within an error circle of $0\\farcs2$. The counterpart is a blue star on the edge of a young cluster of $\\le10^7$ years amid a dominant old stellar population. Its spectral energy distribution is consistent with that for a Z=0.004 star with 8.5 $M_\\odot$ about $5\\times10^6$ years old, or for an O7 V star at solar metallicity. The counterpart exhibited significant variability of $\\Delta m = 0.153\\pm0.033$ mag between two F555W observations separated by three months, reminiscent of the ellipsoidal variability due to the orbital motion of this ULX binary.

  20. Galaxy Cluster Thermal X-Ray Spectra Constrain Axion-Like Particles

    CERN Document Server

    Conlon, Joseph P; Powell, Andrew J

    2015-01-01

    Axion-like particles (ALPs) and photons inter-convert in the presence of a magnetic field. At keV energies in the environment of galaxy clusters, the conversion probability can become unsuppressed for light ALPs. Conversion of thermal X-ray photons into ALPs can introduce a step-like feature into the cluster thermal bremsstrahlung spectrum, and we argue that existing X-ray data on galaxy clusters should be sufficient to extend bounds on ALPs in the low-mass region $m_a \\lesssim 1 \\times 10^{-12}\\,{\\rm eV}$ down to $M \\sim 7\\times 10^{11}\\, {\\rm GeV}$, and that for $10^{11}\\, {\\rm GeV} < M \\lesssim 10^{12}$ GeV light ALPs give rise to interesting and unique observational signatures that may be probed by existing and upcoming X-ray (and potentially X-ray polarisation) observations of galaxy clusters.

  1. Electron cyclotron resonance ion source plasma characterization by X-ray spectroscopy and X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mascali, David, E-mail: davidmascali@lns.infn.it; Castro, Giuseppe; Celona, Luigi; Neri, Lorenzo; Gammino, Santo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Biri, Sándor; Rácz, Richárd; Pálinkás, József [Institute for Nuclear Research (Atomki), Hungarian Academy of Sciences, Bem tér 18/c, H-4026 Debrecen (Hungary); Caliri, Claudia [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università degli Studi di Catania, Dip.to di Fisica e Astronomia, via Santa Sofia 64, 95123 Catania (Italy); Romano, Francesco Paolo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); CNR, Istituto per i Beni Archeologici e Monumentali, Via Biblioteca 4, 95124 Catania (Italy); Torrisi, Giuseppe [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università Mediterranea di Reggio Calabria, DIIES, Via Graziella, I-89100 Reggio Calabria (Italy)

    2016-02-15

    An experimental campaign aiming to investigate electron cyclotron resonance (ECR) plasma X-ray emission has been recently carried out at the ECRISs—Electron Cyclotron Resonance Ion Sources laboratory of Atomki based on a collaboration between the Debrecen and Catania ECR teams. In a first series, the X-ray spectroscopy was performed through silicon drift detectors and high purity germanium detectors, characterizing the volumetric plasma emission. The on-purpose developed collimation system was suitable for direct plasma density evaluation, performed “on-line” during beam extraction and charge state distribution characterization. A campaign for correlating the plasma density and temperature with the output charge states and the beam intensity for different pumping wave frequencies, different magnetic field profiles, and single-gas/gas-mixing configurations was carried out. The results reveal a surprisingly very good agreement between warm-electron density fluctuations, output beam currents, and the calculated electromagnetic modal density of the plasma chamber. A charge-coupled device camera coupled to a small pin-hole allowing X-ray imaging was installed and numerous X-ray photos were taken in order to study the peculiarities of the ECRIS plasma structure.

  2. Multiple station beamline at an undulator x-ray source

    DEFF Research Database (Denmark)

    Als-Nielsen, J.; Freund, A.K.; Grübel, G.

    1994-01-01

    -ray transparent monochromator crystals. Diamond in particular is an attractive monochromator as it is rather X-ray transparent and can be fabricated to a high degree of crystal perfection. Moreover, it has a very high heat conductivity and a rather small thermal expansion so the beam X-ray heat load problem...

  3. Time series analysis of bright galactic X-ray sources

    DEFF Research Database (Denmark)

    Priedhorsky, W. C.; Brandt, Søren; Lund, Niels

    1995-01-01

    We analyze 70 to 110 day data sets from eight bright galactic X-ray binaries observed by WATCH/Eureca, in search of periodic variations. We obtain new epochs for the orbital variation of Cyg X-3 and 4U 1700-37, and confirmation of a dip in Cyg X-1 at superior conjunction of the X-ray star. No evi...

  4. Smoothed Particle Inference: A Kilo-Parametric Method for X-ray Galaxy Cluster Modeling

    OpenAIRE

    Peterson, J. R.; Marshall, P. J.; Andersson, K.

    2005-01-01

    We propose an ambitious new method that models the intracluster medium in clusters of galaxies as a set of X-ray emitting smoothed particles of plasma. Each smoothed particle is described by a handful of parameters including temperature, location, size, and elemental abundances. Hundreds to thousands of these particles are used to construct a model cluster of galaxies, with the appropriate complexity estimated from the data quality. This model is then compared iteratively with X-ray data in t...

  5. A richness study of 14 distant X-ray clusters from the 160 square degree survey

    DEFF Research Database (Denmark)

    McNamara, B.R.; Vikhlinin, A.; Hornstrup, Allan;

    2001-01-01

    We have measured the surface density of galaxies toward 14 X-ray-selected cluster candidates at redshifts z greater than or similar to 0.46 and we show that they are associated with rich galaxy concentrations. These clusters, having X-ray luminosities of L-x(0.5-2) similar to (0.5-2.6) x 10(44) e...

  6. Time-resolved X-ray diffraction with accelerator- and laser-plasma-based X-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Nicoul, Matthieu

    2010-09-01

    Femtosecond X-ray pulses are a powerful tool to investigate atomic motions triggered by femtosecond pump pulses. This thesis is dedicated to the production of such pulses and their use in optical pump - X-ray probe measurement. This thesis describes the laser-plasma-based sources available at the University of Duisburg-Essen. Part of it consists of the description of the design, built-up and characterization of a new ''modular'' X-ray source dedicated to optimize the X-ray flux onto the sample under investigation. The acoustic wave generation in femtosecond optically excited semiconductor (gallium arsenide) and metal (gold) was performed using the sources of the University of Duisburg-Essen. The physical answer of the material was modeled by a simple strain model for the semiconductor, pressure model for the metal, in order to gain information on the interplay of the electronic and thermal pressures rising after excitation. Whereas no reliable information could be obtain in gallium arsenide (principally due to the use of a bulk), the model for gold achieved very good agreement, providing useful information. The relaxation time of the electron to lattice energy was found to be (5.0{+-}0.3) ps, and the ratio of the Grueneisen parameters was found to be {gamma}{sub e} / {gamma}{sub i} = (0.5{+-}0.1). This thesis also describes the Sub-Picosecond Pulse Source (SPPS) which existed at the (formally) Stanford Linear Accelerator Center, an accelerator-based X-ray source, and two measurements performed with it. The first one is the detailed investigation of the phonon softening of the A{sub 1g} mode launch in bismuth upon fluence excitation. Detailed information concerning the new equilibrium position and phonon frequency were obtained over extended laser pump fluences. The second measurement concerned the study of the liquid phase dynamics in a newly formed liquid phase following ultrafast melting in indium antimonide. The formation of the liquid phase

  7. X-ray spectral and timing characteristics of the stars in the young open cluster IC 2391

    CERN Document Server

    Marino, A; Peres, G; Pillitteri, I; Sciortino, S

    2004-01-01

    We present X-ray spectral and timing analysis of members of the young open cluster IC 2391 observed with the XMM-Newton observatory. We detected 99 X-ray sources by analysing the summed data obtained from MOS1, MOS2 and pn detectors of the EPIC camera; 24 of them are members, or probable members, of the cluster. Stars of all spectral types have been detected, from the early-types to the late-M dwarfs. Despite the capability of the instrument to recognize up to 3 thermal components, the X-ray spectra of the G, K and M members of the cluster are well described with two thermal components (at kT$_1 \\sim$ 0.3-0.5 keV and kT$_2 \\sim$ 1.0-1.2 keV respectively) while the X-ray spectra of F members require only a softer 1-T model. The Kolmogorov-Smirnov test applied to the X-ray photon time series shows that approximately 46% of the members of IC 2391 are variable with a confidence level $>$99%. The comparison of our data with those obtained with ROSAT/PSPC, nine years earlier, and ROSAT/HRI, seven years earlier, sho...

  8. The Prospects for Constraining Dark Energy withFuture X-ray Cluster Gas Mass Fraction Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Rapetti, David; Allen, Steven W.

    2007-10-15

    We examine the ability of a future X-ray observatory, with capabilities similar to those planned for the Constellation-X mission, to constrain dark energy via measurements of the cluster X-ray gas mass fraction, fgas. We find that fgas measurements for a sample of {approx}500 hot (kT{approx}> 5keV), X-ray bright, dynamically relaxed clusters, to a precision of {approx}5 percent, can be used to constrain dark energy with a Dark Energy Task Force (DETF; Albrecht et al. 2006) figure of merit of 20-50. Such constraints are comparable to those predicted by the DETF for other leading, planned 'Stage IV' dark energy experiments. A future fgas experiment will be preceded by a large X-ray or SZ survey that will find hot, X-ray luminous clusters out to high redshifts. Short 'snapshot' observations with the new X-ray observatory should then be able to identify a sample of {approx}500 suitably relaxed systems. The redshift, temperature and X-ray luminosity range of interest has already been partially probed by existing X-ray cluster surveys which allow reasonable estimates of the fraction of clusters that will be suitably relaxed for fgas work to be made; these surveys also show that X-ray flux contamination from point sources is likely to be small for the majority of the targets of interest. Our analysis uses a Markov Chain Monte Carlo method which fully captures the relevant degeneracies between parameters and facilities the incorporation of priors and systematic uncertainties in the analysis. We explore the effects of such uncertainties, for scenarios ranging from optimistic to pessimistic. We conclude that the fgas experiment offers a competitive and complementary approach to the best other large, planned dark energy experiments. In particular, the fgas experiment will provide tight constraints on the mean matter and dark energy densities, with a peak sensitivity for dark energy work at redshifts midway between those of supernovae and baryon acoustic

  9. Extended SZ map of the most luminous X-ray cluster, RXJ1347-1145

    CERN Document Server

    Pointecouteau, E; Désert, F X; Alain, B; Bernard, J P; Lamarre, J M; Coron, N

    2000-01-01

    We present in this letter a high resolution (22'' FWHM) extended map at 2.1mm of the Sunyaev-Zel'dovich effect toward the most luminous X-ray cluster, RXJ1347-1145. These observations have been performed with the DIABOLO photometer working at the focus of the 30m IRAM radiotelescope. We have derived a projected gas mass of $(1.1 \\pm 0.1)\\times 10^{14} h_{50}^{-5/2}$M$_{\\odot}$ within an angular radius of $\\theta=74''$ (ie: projected radius of 0.6Mpc, $H_{0}=50$km/s/Mpc, $\\Omega_m=0.3$, $\\Omega_\\Lambda=0.7$). This result matches very well the expected gas mass from the cluster models of X-ray data. With an unprecedented sensitivity level our measurement does not show significant departure from a spherical distribution. The data analysis also allows us to characterize the 2.1mm flux of a well known radio source lying in the center of the cluster: $F_{RS}(2.1\\textrm{mm})=5.7\\pm 1.6$mJy.

  10. On the X-ray Emission from Massive Star Clusters and their Evolving Superbubbles

    CERN Document Server

    Silich, S; Zeferino, G A A; Silich, Sergiy; Tenorio-Tagle, Guillermo; Zeferino, Gabriel Alejandro Anorve

    2005-01-01

    The X-ray emission properties from the hot thermalized plasma that results from the collisions of individual stellar winds and supernovae ejecta within rich and compact star clusters are discussed. We propose a simple analytical way of estimating the X-ray emission generated by super star clusters and derive an expression that indicates how this X-ray emission depends on the main cluster parameters. Our model predicts that the X-ray luminosity from the star cluster region is highly dependent on the star cluster wind terminal speed, a quantity related to the temperature of the thermalized ejecta.We have also compared the X-ray luminosity from the SSC plasma with the luminosity of the interstellar bubbles generated from the mechanical interaction of the high velocity star cluster winds with the ISM.We found that the hard (2.0 keV - 8.0 keV) X-ray emission is usually dominated by the hotter SSC plasma whereas the soft (0.3 keV - 2.0 keV) component is dominated by the bubble plasma. This implies that compact and ...

  11. Chandra X-ray observation of the young stellar cluster NGC 3293 in the Carina Nebula Complex

    Science.gov (United States)

    Preibisch, T.; Flaischlen, S.; Gaczkowski, B.; Townsley, L.; Broos, P.

    2017-09-01

    Context. NGC 3293 is a young stellar cluster at the northwestern periphery of the Carina Nebula Complex that has remained poorly explored until now. Aims: We characterize the stellar population of NGC 3293 in order to evaluate key parameters of the cluster population such as the age and the mass function, and to test claims of an abnormal IMF and a deficit of M ≤ 2.5 M⊙ stars. Methods: We performed a deep (70 ks) X-ray observation of NGC 3293 with Chandra and detected 1026 individual X-ray point sources. These X-ray data directly probe the low-mass (M ≤ 2 M⊙) stellar population by means of the strong X-ray emission of young low-mass stars. We identify counterparts for 74% of the X-ray sources in our deep near-infrared images. Results: Our data clearly show that NGC 3293 hosts a large population of ≈solar-mass stars, refuting claims of a lack of M ≤ 2.5 M⊙ stars. The analysis of the color magnitude diagram suggests an age of 8-10 Myr for the low-mass population of the cluster. There are at least 511 X-ray detected stars with color magnitude positions that are consistent with young stellar members within 7 arcmin of the cluster center. The number ratio of X-ray detected stars in the [1-2 ] M⊙ range versus the M ≥ 5 M⊙ stars (known from optical spectroscopy) is consistent with the expectation from a normal field initial mass function. Most of the early B-type stars and ≈20% of the later B-type stars are detected as X-ray sources. Conclusions: Our data shows that NGC 3293 is one of the most populous stellar clusters in the entire Carina Nebula Complex (very similar to Tr 16 and Tr 15; only Tr 14 is more populous). The cluster probably harbored several O-type stars, whose supernova explosions may have had an important impact on the early evolution of the Carina Nebula Complex. The Chandra data described in this paper have been obtained in the open time project with ObsID 16648 (PI: T. Preibisch) ivo://ADS/Sa.CXO#obs/16648.Tables 1-3 are only

  12. A Chandra X-ray observation of the globular cluster Terzan 1

    CERN Document Server

    Cackett, E M; Heinke, C O; Pooley, D; Lewin, W H G; Grindlay, J E; Edmonds, P D; Jonker, P G; Miller, J M

    2005-01-01

    We present a 19 ks Chandra ACIS-S observation of the globular cluster Terzan 1. Fourteen sources are detected within 1.4 arcmin of the cluster center with 2 of these sources predicted to be not associated with the cluster (background AGN or foreground objects). The neutron star X-ray transient, X1732-304, has previously been observed in outburst within this globular cluster with the outburst seen to last for at least 12 years. Here we find 4 sources that are consistent with the ROSAT position for this transient, but none of the sources are fully consistent with the position of a radio source detected with the VLA that is likely associated with the transient. The most likely candidate for the quiescent counterpart of the transient has a relatively soft spectrum and an unabsorbed 0.5-10 keV luminosity of 2.6E32 ergs/s, quite typical of other quiescent neutron stars. Assuming standard core cooling, from the quiescent flux of this source we predict long (>400 yr) quiescent episodes to allow the neutron star to co...

  13. A proposal for a collecting mirror assembly for large divergence x-ray sources.

    Science.gov (United States)

    Ichimaru, Satoshi; Hatayama, Masatoshi; Ohchi, Tadayuki; Oku, Satoshi

    2014-11-01

    We propose a new type of collecting mirror assembly (CMA) for x rays, which will enable us to build a powerful optical system for collecting x rays from large divergence sources. The CMA consists of several mirror sections connected in series. The angle of each section is designed so that the x rays reflected from it are parallel to the x rays directly incident on the following sections. A simplified CMA structure is designed and applied to the Al-Kα emission line. It is estimated that by using the CMA the number of x rays detected could be increased by a factor of about 2.5.

  14. Short X-ray pulses from third-generation light sources.

    Science.gov (United States)

    Stepanov, A G; Hauri, C P

    2016-01-01

    High-brightness X-ray radiation produced by third-generation synchrotron light sources (TGLS) has been used for numerous time-resolved investigations in many different scientific fields. The typical time duration of X-ray pulses delivered by these large-scale machines is about 50-100 ps. A growing number of time-resolved studies would benefit from X-ray pulses with two or three orders of magnitude shorter duration. Here, techniques explored in the past for shorter X-ray pulse emission at TGLS are reviewed and the perspective towards the realisation of picosecond and sub-picosecond X-ray pulses are discussed.

  15. LIGHT SOURCE: A simulation study of Tsinghua Thomson scattering X-ray source

    Science.gov (United States)

    Tang, Chuan-Xiang; Li, Ren-Kai; Huang, Wen-Hui; Chen, Huai-Bi; Du, Ying-Chao; Du, Qiang; Du, Tai-Bin; He, Xiao-Zhong; Hua, Jian-Fei; Lin, Yu-Zhen; Qian, Hou-Jun; Shi, Jia-Ru; Xiang, Dao; Yan, Li-Xin; Yu, Pei-Cheng

    2009-06-01

    Thomson scattering X-ray sources are compact and affordable facilities that produce short duration, high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies, and also medical and industrial applications. Such a facility has been built at the Accelerator Laboratory of Tsinghua University, and upgrade is in progress. In this paper, we present a proposed layout of the upgrade with design parameters by simulation, aiming at high X-ray pulses flux and brightness, and also enabling advanced dynamics studies and applications of the electron beam. Design and construction status of main subsystems are also presented.

  16. Is the Variable X-ray Source in M82 due to Gravitational Lensing?

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    We explore the possibility of attributing the recent discovery of the variable hard X-ray source CXO M82 J095550.2+694047 in M82 to the gravitational magnification by an intervening stellar object along the line of sight acting as a mi-crolens. The duration of the event (> 84 days) allows us to set robust constraints on the mass and location of the microlensing object when combined with the dynam-ical properties of the Galactic halo, M82 and typical globular clusters. Except for the extremely low probability, the microlensing magnification by MACHO in either the Galactic halo or M82 halo is able to explain the X-ray variability of CXO M82 J095550.2+694047. It is hoped that the lensing hypothesis can be tested soon by measurement of the light curve.

  17. The cosmological analysis of X-ray cluster surveys; III. Bypassing cluster mass measurements

    CERN Document Server

    Pierre, M; Faccioli, L; Clerc, N; Gastaud, R; Koulouridis, E; Pacaud, F

    2016-01-01

    Despite strong theoretical arguments, the use of clusters as cosmological probes is, in practice, frequently questioned because of the many uncertainties impinging on cluster mass estimates. Our aim is to develop a fully self-consistent cosmological approach of X-ray cluster surveys, exclusively based on observable quantities, rather than masses. This procedure is justified given the possibility to directly derive the cluster properties via ab initio modelling, either analytically or by using hydrodynamical simulations. In this third paper, we evaluate the method on cluster toy-catalogues. We model the population of detected clusters in the count-rate -- hardness-ratio -- angular size -- redshift space and compare the corresponding 4-dimensional diagram with theoretical predictions. The best cosmology+physics parameter configuration is determined using a simple minimisation procedure; errors on the parameters are derived by scanning the likelihood hyper-surfaces with a wide range of starting values. The metho...

  18. BRIGHTEST X-RAY CLUSTERS OF GALAXIES IN THE CFHTLS WIDE FIELDS: CATALOG AND OPTICAL MASS ESTIMATOR

    Energy Technology Data Exchange (ETDEWEB)

    Mirkazemi, M.; Finoguenov, A.; Lerchster, M.; Erfanianfar, G.; Seitz, S. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, D-85740 Garching (Germany); Pereira, M. J.; Egami, E. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Tanaka, M. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Brimioulle, F. [Universitätssternwarte München, Scheinerstrasse 1, D-81679 München (Germany); Kettula, K. [Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-00014 Helsinki (Finland); McCracken, H. J.; Mellier, Y. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Université Pierre et Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Kneib, J. P. [Laboratoire d' Astrophysique de Marseille, CNRS-Université, Ple de l' Etoile Site de Château-Gombert 38, rue Frédéric Joliot-Curie, F-13388 Marseille Cedex 13 (France); Rykoff, E. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Erben, T. [Argelander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany); Taylor, J. E., E-mail: kazemi@mpe.mpg.de [Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada)

    2015-01-20

    The Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) presents a unique data set for weak-lensing studies, having high-quality imaging and deep multiband photometry. We have initiated an XMM-CFHTLS project to provide X-ray observations of the brightest X-ray-selected clusters within the wide CFHTLS area. Performance of these observations and the high quality of CFHTLS data allow us to revisit the identification of X-ray sources, introducing automated reproducible algorithms, based on the multicolor red sequence finder. We have also introduced a new optical mass proxy. We provide the calibration of the red sequence observed in the Canada-France-Hawaii filters and compare the results with the traditional single-color red sequence and photo-z. We test the identification algorithm on the subset of highly significant XMM clusters and identify 100% of the sample. We find that the integrated z-band luminosity of the red sequence galaxies correlates well with the X-ray luminosity, with a surprisingly small scatter of 0.20 dex. We further use the multicolor red sequence to reduce spurious detections in the full XMM and ROSAT All-Sky Survey (RASS) data sets, resulting in catalogs of 196 and 32 clusters, respectively. We made spectroscopic follow-up observations of some of these systems with HECTOSPEC and in combination with BOSS DR9 data. We also describe the modifications needed to the source detection algorithm in order to maintain high purity of extended sources in the shallow X-ray data. We also present the scaling relation between X-ray luminosity and velocity dispersion.

  19. A Radio-Selected Black Hole X-ray Binary Candidate in the Milky Way Globular Cluster M62

    CERN Document Server

    Chomiuk, Laura; Maccarone, Thomas J; Miller-Jones, James C A; Heinke, Craig; Noyola, Eva; Seth, Anil C; Ransom, Scott

    2013-01-01

    We report the discovery of a candidate stellar-mass black hole in the Milky Way globular cluster M62. We detected the black hole candidate, which we term M62-VLA1, in the core of the cluster using deep radio continuum imaging from the Karl G. Jansky Very Large Array. M62-VLA1 is a faint source, with a flux density of 18.7 +/- 1.9 microJy at 6.2 GHz and a flat radio spectrum (alpha=-0.24 +/- 0.42, for S_nu = nu^alpha). M62 is the second Milky Way cluster with a candidate stellar-mass black hole; unlike the two candidate black holes previously found in the cluster M22, M62-VLA1 is associated with a Chandra X-ray source, supporting its identification as a black hole X-ray binary. Measurements of its radio and X-ray luminosity, while not simultaneous, place M62-VLA1 squarely on the well-established radio--X-ray correlation for stellar-mass black holes. In archival Hubble Space Telescope imaging, M62-VLA1 is coincident with a star near the lower red giant branch. This possible optical counterpart shows a blue exce...

  20. A carbon nanotube field emission multipixel x-ray array source for microradiotherapy application

    OpenAIRE

    Wang, Sigen; Calderon, Xiomara; Peng, Rui; Schreiber, Eric C.; Zhou, Otto; Chang, Sha

    2011-01-01

    The authors report a carbon nanotube (CNT) field emission multipixel x-ray array source for microradiotherapy for cancer research. The developed multipixel x-ray array source has 50 individually controllable pixels and it has several distinct advantages over other irradiation source including high-temporal resolution (millisecond level), the ability to electronically shape the form, and intensity distribution of the radiation fields. The x-ray array was generated by a CNT cathode array (5×10)...

  1. X-Ray bright active galactic nuclei in massive galaxy clusters - II. The fraction of galaxies hosting active nuclei

    DEFF Research Database (Denmark)

    Ehlert, S.; von der Linden, A.; Allen, S. W.

    2013-01-01

    We present a measurement of the fraction of cluster galaxies hosting X-ray bright active galactic nuclei (AGN) as a function of clustercentric distance scaled in units of r500. Our analysis employs high-quality Chandra X-ray and Subaru optical imaging for 42 massive X-ray-selected galaxy cluster...

  2. Planck early results. X. Statistical analysis of Sunyaev-Zeldovich scaling relations for X-ray galaxy clusters

    DEFF Research Database (Denmark)

    Bucher, M.; Delabrouille, J.; Giraud-Héraud, Y.;

    2011-01-01

    All-sky data from the Planck survey and the Meta-Catalogue of X-ray detected Clusters of galaxies (MCXC) are combined to investigate the relationship between the thermal Sunyaev-Zeldovich (SZ) signal and X-ray luminosity. The sample comprises ~1600 X-ray clusters with redshifts up to ~1 and spans...

  3. Performance of the Cygnus X-ray Source

    Science.gov (United States)

    Smith, John R.; Carlson, Randolph; Fulton, Robert D.; Altes, R.; Carboni, V.; Chavez, Jacob R.; Corcoran, P.; Coulter, William L.; Douglas, J.; Droemer, D.; Gibson, William A.; Helvin, Thomas B.; Henderson, David J.; Johnson, David L.; Maenchen, John E.; Mitton, Charlas V.; Molina, Isidro; Nishimoto, H.; Ormond, Eugene C.; Ortega, Paul A.; Quicksilver, Robert J.; Ridlon, Rae N.; Rose, Evan A.; Scholfield, David W.; Smith, I.; Valerio, Antonio R.; White, R.

    2002-12-01

    Cygnus is a radiographic x-ray source developed for support of the Sub-Critical Experiments Program at the Nevada Test Site. Major requirements for this application are: a dramatically reduced spot size as compared to both Government Laboratory and existing commercial alternatives, layout flexibility, and reliability. Cygnus incorporates proven pulsed power technology (Marx Generator, Pulse Forming Line, Water Transmission Line, and Inductive Voltage Adder sub-components) to drive a high voltage vacuum diode. In the case of Cygnus, a relatively new approach (the rod pinch diode [1]) is employed to achieve a small source diameter. Design specifications are: 2.25 MeV endpoint energy, 3 rads dose at 1 meter. The pulsed power and system architecture design plan has been previously presented [2]. The first set of Cygnus shots were geared to verification of electrical parameters and, therefore, used a large area diode configuration offering increased shot rate as compared to that of the rod pinch diode. In this paper we present results of initial rod pinch operation in terms of electrical and radiation parameters.

  4. Nature of the Extreme Ultraluminous X-ray Sources

    CERN Document Server

    Wiktorowicz, Grzegorz; Sadowski, Aleksander; Belczynski, Krzysztof

    2015-01-01

    In this proof-of-concept study we demonstrate how a binary system can easily form an extreme ULX source with the X-ray luminosity of L_x > 10^42 erg/s. Formation efficiencies and lifetimes of such objects are high enough to potentially explain all observed extreme ULXs. These systems are not only limited to binaries with stellar-origin black hole accretors. Noteworthy, we have also identified such objects with neutron stars. Typically, a 10 Msun black hole is fed by a massive (~10 Msun) Hertzsprung gap donor with Roche lobe overflow rate of ~10^-3 Msun/yr (~2600 Mdot_Edd). For neutron star systems the typical donors are evolved low-mass (~2 Msun) helium stars with Roche lobe overflow rate of ~10^-2 Msun/yr. We base our study purely on the available Roche lobe overflow rate in a binary system and show that if only even a small fraction (>10^-3) of the overflow reaches the BH, the source will be super-Eddington. Our study does not prove that any particular extreme ULX (e.g., HLX-1) is a regular binary system wi...

  5. Spectral variability of ultraluminous X-ray sources

    CERN Document Server

    Kajava, Jari J E

    2008-01-01

    We study spectral variability of 11 ultraluminous X-ray sources (ULX) using archived XMM-Newton and Chandra observations. We use three models to describe the observed spectra; a power-law, a multi-colour disk (MCD) and a combination of these two models. We find that out of the 11 ULXs in our sample, 7 ULXs show a correlation between the luminosity and the photon index Gamma (hereafter L-Gamma correlation). Furthermore, out of the 7 ULXs that have the L-Gamma correlation, 4 ULXs also show spectral pivoting in the observed energy band. We also find that two ULXs show an L-Gamma anti-correlation. The spectra of 4 ULXs in the sample can be adequately fitted with a MCD model. We compare these sources to known black hole binaries (BHB) and find that they follow similar paths in their luminosity-temperature (hereafter L-T) diagrams. Finally we show that the 'soft excess' reported for many of these ULXs at 0.2 keV seem to follow a trend L \\propto T^{-4} when modeled with a power-law plus a 'cool' MCD model. This is c...

  6. Spectral variability of ultraluminous X-ray sources

    CERN Document Server

    Kajava, Jari J E

    2009-01-01

    We study spectral variability of 11 ultraluminous X-ray sources (ULX) using archived XMM-Newton and Chandra observations. We use three models to describe the observed spectra: a power-law, a multi-colour disc (MCD) and a combination of these two models. We find that 7 ULXs show a correlation between the luminosity Lx and the photon index Gamma. Furthermore, 4 out of these 7 ULXs also show spectral pivoting in the observed energy band. We also find that two ULXs show an Lx-Gamma anti-correlation. The spectra of 4 ULXs in the sample can be adequately fitted with a MCD model. We compare these sources to known black hole binaries (BHB) and find that they follow similar paths in their luminosity-temperature diagrams. Finally we show that the `soft excess' reported for many of these ULXs at about 0.2 keV seems to roughly follow a trend Lsoft \\propto T^{-3.5} when modelled with a power-law plus a `cool' MCD model. This is contrary to the L \\propto T^4 relation that is expected from theory and what is seen for many a...

  7. Sub-Picosecond Tunable Hard X-Ray Undulator Source for Laser/X-Ray Pump-Probe Experiments

    Science.gov (United States)

    Ingold, G.; Beaud, P.; Johnson, S.; Streun, A.; Schmidt, T.; Abela, R.; Al-Adwan, A.; Abramsohn, D.; Böge, M.; Grolimund, D.; Keller, A.; Krasniqi, F.; Rivkin, L.; Rohrer, M.; Schilcher, T.; Schmidt, T.; Schlott, V.; Schulz, L.; van der Veen, F.; Zimoch, D.

    2007-01-01

    The FEMTO source under construction at the μXAS beamline is designed to enable tunable time-resolved laser/x-ray absorption and diffraction experiments in photochemistry and condensed matter with ps- and sub-ps resolution. The design takes advantage of (1) the highly stable operation of the SLS storage ring, (2) the reliable high harmonic operation of small gap, short period undulators to generate hard x-rays with energy 3-18 keV at 2.4 GeV beam energy, and (3) the progress in high power, high repetition rate fs solid-state laser technology to employ laser/e-beam `slicing' to reach a time resolution of ultimately 100 fs. The source will profit from the inherently synchronized pump (laser I: 100 fs, 2 mJ, 1 kHz) and probe (sliced X-rays, laser II: 50 fs, 5 mJ, 1 kHz) pulses, and from the excellent stability of the SLS storage ring which is operated in top-up mode and controlled by a fast orbit feedback (FOFB). Coherent radiation emitted at THz frequencies by the sliced 100 fs electron bunches will be monitored as on-line cross-correlation signal to keep the laser-electron beam interaction at optimum. The source is designed to provide at 8 keV (100 fs) a monochromized flux of 104 ph/s/0.01% bw (Si crystal monochromator) and 106 ph/s/1.5% bw (multilayer monochromator) at the sample. It is operated in parasitic mode using a hybrid bunch filling pattern. Because of the low intensity measurements are carried out repetitively over many shots using refreshing samples and gated detectors. `Diffraction gating' experiments will be used to characterize the sub-ps X-ray pulses.

  8. The XXL Survey: VI. The 1000 brightest X-ray point sources

    CERN Document Server

    Fotopoulou, S; Paltani, S; Ranalli, P; Ramos-Ceja, M E; Faccioli, L; Plionis, M; Adami, C; Bongiorno, A; Brusa, M; Chiappetti, L; Desai, S; Elyiv, A; Lidman, C; Melnyk, O; Pierre, M; Piconcelli, E; Vignali, C; Alis, S; Ardila, F; Arnouts, S; Baldry, I; Bremer, M; Eckert, D; Guennou, L; Horellou, C; Iovino, A; Koulouridis, E; Liske, J; Maurogordato, S; Menanteau, F; Mohr, J J; Owers, M; Poggianti, B; Pompei, E; Sadibekova, T; Stanford, A; Tuffs, R; Willis, J

    2016-01-01

    X-ray extragalactic surveys are ideal laboratories for the study of the evolution and clustering of active galactic nuclei (AGN). The XXL Survey spans two fields of a combined 50 $deg^2$ observed for more than 6Ms with XMM-Newton, occupying the parameter space between deep surveys and very wide area surveys; at the same time it benefits from a wealth of ancillary data. This paper marks the first release of the XXL point source catalogue selected in the 2-10 keV energy band with limiting flux $F_{2-10keV}=4.8\\cdot10^{-14}\\rm{erg\\,s^{-1}\\,cm^{-2}}$. We use both public and proprietary data sets to identify the counterparts of the X-ray point-like sources and improved upon the photometric redshift determination for AGN by applying a Random Forest classification trained to identify for each object the optimal photometric redshift model library. We also assign a probability to each source to be a star or an outlier. We model with Bayesian analysis the X-ray spectra assuming a power-law model with the presence of an...

  9. The Ultraluminous X-ray Sources near the Center of M82

    CERN Document Server

    Kong, A K H; Hsieh, P -Y; Mak, D S Y; Pun, C S J

    2007-01-01

    We report the discovery of a recurrent ultraluminous X-ray source(ULX), a background AGN, and a young supernova remnant near the center of the starburst galaxy M82. From a series of Chandra observations taken from 1999 to 2005, we found that the ULX first appeared in 1999 October. The source turned off in 2000 January, but later reappeared and has been active since then. The X-ray luminosity of this source varies from below the detection level (~ 2.5e38 erg/s) to its active state in between ~8e39 erg/s and 1.3e40 erg/s (in the 0.5-10 keV energy band) and shows unusual spectral changes. The X-ray spectra are best fitted with an absorbed power-law model with photon index ranging from 1.3 to 1.7. The spectra are similar to those Galactic black hole binary candidates seen in the low/hard state except that a very hard spectrum was seen in one of the observations. By comparing with near infrared images taken with the Hubble Space Telescope, the ULX is found to be located within a young star cluster. Radio imaging i...

  10. X-ray imaging detectors for synchrotron and XFEL sources

    Directory of Open Access Journals (Sweden)

    Takaki Hatsui

    2015-05-01

    Full Text Available Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL experiments provide high-frame-rate integrating detectors with both high sensitivity and high peak signal. Similar performance improvements are sought in monolithic detectors. The monolithic approach also offers a lower noise floor, which is required for the detection of soft X-ray photons. The link between technology development and detector performance is described briefly in the context of potential future capabilities for X-ray imaging detectors.

  11. X-ray imaging detectors for synchrotron and XFEL sources.

    Science.gov (United States)

    Hatsui, Takaki; Graafsma, Heinz

    2015-05-01

    Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL) experiments provide high-frame-rate integrating detectors with both high sensitivity and high peak signal. Similar performance improvements are sought in monolithic detectors. The monolithic approach also offers a lower noise floor, which is required for the detection of soft X-ray photons. The link between technology development and detector performance is described briefly in the context of potential future capabilities for X-ray imaging detectors.

  12. Miniature X-ray Source for Planetary Exploration Instruments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the proposed work is to develop a design model for a CNT cold cathode, low power, passively cooled, and grounded-anode X-ray tube that is compatible...

  13. The X-ray properties of optically-selected z>0.6 clusters in the ESO Distant Cluster Survey

    CERN Document Server

    Johnson, O; Zaritsky, D; Clowe, D; Aragón-Salamanca, A; Halliday, C; Jablonka, P; Milvang-Jensen, B; Pellò, R; Poggianti, B M; Rudnick, G; Saglia, R; Simard, L; White, S

    2006-01-01

    We present XMM-Newton observations of three optically-selected z > 0.6 clusters from the ESO Distant Cluster Survey (EDisCS), comprising the first results of a planned X-ray survey of the full EDisCS high-redshift sample. The EDisCS clusters were identified in the Las Campanas Distant Cluster Survey as surface brightness fluctuations in the optical sky and their masses and galaxy populations are well described by extensive photometric and spectroscopic observations. We detect two of the three clusters in the X-ray and place a firm upper limit on diffuse emission in the third cluster field. We are able to constrain the X-ray luminosity and temperature of the detected clusters and estimate their masses. We find the X-ray properties of the detected EDisCS clusters are similar to those of X-ray-selected clusters of comparable mass and -- unlike other high-redshift, optically-selected clusters -- are consistent with the T - sigma and L_x - sigma relations determined from X-ray selected clusters at low redshift. Th...

  14. X-ray imaging detectors for synchrotron and XFEL sources

    OpenAIRE

    Takaki Hatsui; Heinz Graafsma

    2015-01-01

    Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL) experiments provide high-frame-rate integrating detectors with both high sensitivit...

  15. Discovery of a new accreting millisecond X-ray pulsar in the globular cluster NGC 2808

    CERN Document Server

    Sanna, A; Burderi, L; Bozzo, E; Riggio, A; Di Salvo, T; Ferrigno, C; Rea, N; Iaria, R

    2016-01-01

    We report on the discovery of coherent pulsations at a period of 2.9 ms from the X-ray transient MAXI J0911-655 in the globular cluster NGC 2808. We observed X-ray pulsations at a frequency of $\\sim339.97$ Hz in three different observations of the source performed with XMM-Newton and NuSTAR during the source outburst. This newly discovered accreting millisecond pulsar is part of an ultra-compact binary system characterised by an orbital period of $44.3$ minutes and a projected semi-major axis of $\\sim17.6$ lt-ms. Based on the mass function we estimate a minimum companion mass of 0.024 M$_{\\odot}$, which assumes a neutron star mass of 1.4 M$_{\\odot}$ and a maximum inclination angle of $75^{\\circ}$ (derived from the lack of eclipses and dips in the light-curve of the source). We find that the companion star's Roche-Lobe could either be filled by a hot ($5\\times 10^{6}$ K) pure helium white dwarf with a 0.028 M$_{\\odot}$ mass (implying $i\\simeq58^{\\circ}$) or an old (>5 Gyr) brown dwarf with metallicity abundanc...

  16. Spectral clustering for optical confirmation and redshift estimation of X-ray selected galaxy cluster candidates in the SDSS Stripe 82

    Science.gov (United States)

    Mahmoud, E.; Takey, A.; Shoukry, A.

    2016-07-01

    We develop a galaxy cluster finding algorithm based on spectral clustering technique to identify optical counterparts and estimate optical redshifts for X-ray selected cluster candidates. As an application, we run our algorithm on a sample of X-ray cluster candidates selected from the third XMM-Newton serendipitous source catalog (3XMM-DR5) that are located in the Stripe 82 of the Sloan Digital Sky Survey (SDSS). Our method works on galaxies described in the color-magnitude feature space. We begin by examining 45 galaxy clusters with published spectroscopic redshifts in the range of 0.1-0.8 with a median of 0.36. As a result, we are able to identify their optical counterparts and estimate their photometric redshifts, which have a typical accuracy of 0.025 and agree with the published ones. Then, we investigate another 40 X-ray cluster candidates (from the same cluster survey) with no redshift information in the literature and found that 12 candidates are considered as galaxy clusters in the redshift range from 0.29 to 0.76 with a median of 0.57. These systems are newly discovered clusters in X-rays and optical data. Among them 7 clusters have spectroscopic redshifts for at least one member galaxy.

  17. X-ray properties of the young open clusters HM1 and IC2944/2948

    CERN Document Server

    Naze, Yael; Sana, Hugues; Corcoran, Michael F

    2013-01-01

    Using XMM data, we study for the first time the X-ray emission of HM1 and IC2944/2948. Low-mass, pre-main-sequence objects with an age of a few Myr are detected, as well as a few background or foreground objects. Most massive stars in both clusters display the usual high-energy properties of that type of objects, though with log(Lx/Lbol) apparently lower in HM1 than in IC2944/2948. Compared with studies of other clusters, it seems that a low signal-to-noise ratio at soft energies, due to the high extinction, may be the main cause of this difference. In HM1, the two Wolf-Rayet stars show contrasting behaviors: WR89 is extremely bright, but much softer than WR87. It remains to be seen whether wind-wind collisions or magnetically confined winds can explain these emissions. In IC2944/2948, the X-ray sources concentrate around HD101205; a group of massive stars to the north of this object is isolated, suggesting that there exist two subclusters in the field-of-view.

  18. X-ray Properties of the Young Open Clusters HM1 and IC 2944-2948

    Science.gov (United States)

    Naze, Y.; Rauw, G.; Sana, H.; Corcoran, Michael F.

    2013-01-01

    Using XMM-Newton data, we study for the first time the X-ray emission of HM1 and IC 2944/2948. Low-mass, pre-main-sequence objects with an age of a few Myr are detected, as well as a few background or foreground objects. Most massive stars in both clusters display the usual high-energy properties of that type of objects, though with log [L(sub X)/L(sub BOL)] apparently lower in HM1 than in IC2944/2948. Compared with studies of other clusters, it seems that a low signal-to-noise ratio at soft energies, due to the high extinction, may be the main cause of this difference. In HM1, the two Wolf-Rayet stars show contrasting behaviors:WR89 is extremely bright, but much softer than WR87. It remains to be seen whether wind-wind collisions or magnetically confined winds can explain these emissions. In IC 2944/2948, the X-ray sources concentrate around HD 101205; a group of massive stars to the north of this object is isolated, suggesting that there exist two subclusters in the field-of-view.

  19. The BeppoSAX High Energy Large Area Survey. IV. On the soft X-ray properties of the hard X-ray-selected HELLAS sources

    CERN Document Server

    Vignali, C; Fiore, F; La Franca, F

    2001-01-01

    We present a comprehensive study of the soft X-ray properties of the BeppoSAX High-Energy Large Area Survey (HELLAS) sources. A large fraction (about 2/3) of the hard X-ray selected sources is detected by ROSAT. The soft X-ray colors for many of these objects, along with the 0.5-2 keV flux upper limits for those undetected in the ROSAT band, do imply the presence of absorption. The comparison with the ROSAT Deep Survey sources indicates that a larger fraction of absorbed objects among the HELLAS sources is present, in agreement with their hard X-ray selection and the predictions of the X-ray background synthesis models. Another striking result is the presence of a soft (additional) X-ray component in a significant fraction of absorbed objects.

  20. Weak lensing observation of potentially X-ray underluminous galaxy clusters

    CERN Document Server

    Dietrich, J P; Popesso, P; Zhang, Y -Y; Lombardi, M; Böhringer, H

    2009-01-01

    Optically selected clusters of galaxies display a relation between their optical mass estimates and their X-ray luminosities Lx with a large scatter. A substantial fraction of optically selected clusters have Lx estimates or upper limits significantly below the values expected from the Lx-mass relation established for X-ray selected clusters, i.e., these clusters are X-ray underluminous for their mass. Here we aim to confirm or falsify the X-ray underluminous nature of two clusters, Abell 315 and Abell 1456, with weak gravitational lensing as a third and independent measure of the clusters' masses. We obtained optical wide-field imaging data and selected background galaxies using their colors and measured the shear exerted by the tidal field of the foreground galaxy clusters. We then fitted parametrized models to our shear catalogs. After accounting for projections of large-scale structure and halo triaxiality we find that A~315 is significantly X-ray underluminous for its mass, while no significant lensing s...

  1. Background X-ray Radiation Fields Produced by Young Embedded Star Clusters

    CERN Document Server

    Adams, Fred; Holden, Lisa

    2012-01-01

    Most star formation in our galaxy occurs within embedded clusters, and these background environments can affect the star and planet formation processes occurring within them. In turn, young stellar members can shape the background environment and thereby provide a feedback mechanism. This work explores one aspect of stellar feedback by quantifying the background X-ray radiation fields produced by young stellar objects. Specifically, the distributions of X-ray luminosities and X-ray fluxes produced by cluster environments are constructed as a function of cluster membership size $N$. Composite flux distributions, for given distributions of cluster sizes $N$, are also constructed. The resulting distributions are wide and the X-ray radiation fields are moderately intense, with the expected flux levels exceeding the cosmic and galactic X-ray backgrounds by factors of $\\sim10-1000$ (for energies 0.2 -- 15 keV). For circumstellar disks that are geometrically thin and optically thick, the X-ray flux from the backgrou...

  2. Structure investigation of metal ions clustering in dehydrated gel using x-ray anomalous dispersion effect

    CERN Document Server

    Soejima, Y; Sugiyama, M; Annaka, M; Nakamura, A; Hiramatsu, N; Hara, K

    2003-01-01

    The structure of copper ion clusters in dehydrated N-isopropylacrylamide/sodium acrylate (NIPA/SA) gel has been studied by means of small angle X-ray scattering (SAXS) method. In order to distinguish the intensity scattered by Cu ions, the X-ray anomalous dispersion effect around the Cu K absorption edge has been coupled with SAXS. It is found that the dispersion effect dependent on the incident X-ray energy is remarkable only at the momentum transfer q = 0.031 A sup - sup 1 , where a SAXS peak is observed. The results indicate that copper ions form clusters in the dehydrated gel, and that the mean size of clusters is the same as that of SA clusters produced by microphase separation. It is therefore naturally presumed that copper ions are adsorbed into the SA molecules. On the basis of the presumption, a mechanism is proposed for microphase-separation and clustering of Cu ions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cool, Adrienne M.; Arias, Tersi; Brochmann, Michelle; Dorfman, Jason; Gafford, April; White, Vivian [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); Haggard, Daryl [Center for Interdisciplinary Exploration and Research in Astrophysics, Physics and Astronomy Department, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Anderson, Jay, E-mail: cool@sfsu.edu, E-mail: dhaggard@northwestern.edu [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

    2013-02-15

    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 {approx}10' Multiplication-Sign 10' of the cluster and encompass 109 known Chandra sources. We find promising optical counterparts for 59 of the sources, {approx}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 {sub 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 {omega} 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 {omega} to Cen 20, the largest number yet known in any globular cluster.

  4. The heating of X-ray gas by radio gas in cluster PKS0745-191

    Science.gov (United States)

    Xiang, F.; Chen, Y.; Wu, M.; Lu, F. J.; Song, L. M.; Jia, S. M..

    2004-05-01

    A calculation about the energy evolution of the relativistic particles in galaxy clusters is presented. The heating of X-ray gas by radio gas in cluster PKS 0745-191 is derived through a combined analysis of Chandra data and VLA radio observations. It was found that the heating of X-ray gas by radio gas is not enough to supply the energy lose by the X-ray emission when the low energy cut-off in the power-law spectrum of the relativistic electrons is set to 0.001erg. Therefore further computing is made to study the heating of X-ray gas by radio gas with different low energy cut-off is computed and the low energy cut-off values.

  5. A radio monitoring survey of ultra-luminous X-ray sources

    NARCIS (Netherlands)

    Körding, E.; Colbert, E.; Falcke, H.D.E.

    2005-01-01

    We present the results of a radio monitoring campaign to search for radio emission from nearby ultra-luminous X-ray sources (ULXs). These sources are bright off-nuclear X-ray point sources with luminosities exceeding LX > 1039 erg s-1. A well-defined sample of the 9

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

    CERN Document Server

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

    2012-01-01

    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 (WFC) images obtained using F625W, F435W, and F658N filters; with 9 pointings we cover the central ~10'x10' 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 SDSS (Gansicke et al. 2009). Additional optical counterparts include three BY Dra candidates, a possible blue straggler, and a previously-reported quiescent low-mass X-ray ...

  7. The X-ray eclipse geometry of the super-soft X-ray source CAL 87

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, T.; Lopes de Oliveira, R. [Departamento de Física, Universidade Federal de Sergipe, Av. Marechal Rondon s/n, 49100-000 São Cristóvão, SE (Brazil); Borges, B. W., E-mail: tribeiro@ufs.br, E-mail: rlopes@ufs.br, E-mail: bernardo@astro.ufsc.br [Universidade Federal de Santa Catarina, Campus Araranguá, 88905-120 Araranguá, SC (Brazil)

    2014-09-01

    We explore XMM-Newton observations of the eclipsing super-soft X-ray source CAL 87 in order to map the accretion structures of the system. Indirect imaging techniques were applied in X-ray light curves to provide eclipse maps. The surface brightness distribution exhibits an extended and symmetric emission, and a feature is revealed from the hardest X-rays that is likely due to a bright spot. A rate of P-dot =(+6±2)×10{sup −10} for changes in the orbital period of the system was derived from the eclipses. There is no significant variation of the emission lines even during eclipses, arguing that the lines are formed in an extended region. The continuum emission dominates the decrease in flux that is observed during eclipses. The O VIII Lyα line reveals a broadening velocity that is estimated to be 365{sub −69}{sup +65} km s{sup –1} (at 1σ), marginal evidence for asymmetry in its profile, and sometimes shows evidence of double-peaked emission. Together, the results support that the wind-driven mass transfer scenario is running in CAL 87.

  8. The scaling of X-ray variability with luminosity in Ultra-luminous X-ray sources

    CERN Document Server

    Gonzalez-Martin, O; Reig, P; Zezas, A

    2010-01-01

    We investigated the relationship between the X-ray variability amplitude and X-ray luminosity for a sample of 14 bright Ultra-luminous X-ray sources (ULXs) with XMM-Newton/EPIC data, and compare it with the well established similar relationship for Active Galactic Nuclei (AGN). We computed the normalised excess variance in the 2-10 keV light curves of these objects and their 2-10 keV band intrinsic luminosity. We also determined model "variability-luminosity" relationships for AGN, under several assumptions regarding their power-spectral shape. We compared these model predictions at low luminosities with the ULX data. The variability amplitude of the ULXs is significantly smaller than that expected from a simple extrapolation of the AGN "variability-luminosity" relationship at low luminosities. We also find evidence for an anti-correlation between the variability amplitude and L(2-10 keV) for ULXs. The shape of this relationship is consistent with the AGN data but only if the ULXs data are shifted by four ord...

  9. The spatial, spectral and polarization properties of solar flare X-ray sources

    CERN Document Server

    Jeffrey, Natasha L S

    2014-01-01

    X-rays are a valuable diagnostic tool for the study of high energy accelerated electrons. Bremsstrahlung X-rays produced by, and directly related to, high energy electrons accelerated during a flare, provide a powerful diagnostic tool for determining both the properties of the accelerated electron distribution, and of the flaring coronal and chromospheric plasmas. This thesis is specifically concerned with the study of spatial, spectral and polarization properties of solar flare X-ray sources via both modelling and X-ray observations using the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Firstly, a new model is presented, accounting for finite temperature, pitch angle scattering and initial pitch angle injection. This is developed to accurately infer the properties of the acceleration region from the observations of dense coronal X-ray sources. Moreover, examining how the spatial properties of dense coronal X-ray sources change in time, interesting trends in length, width, position, number density ...

  10. First Hard X-Ray Detection of the Non-Thermal Emission Around the Arches Cluster: Morphology and Spectral Studies With NuSTAR

    Science.gov (United States)

    Krivonos, Roman A.; Tomsick, John A.; Bauer, Franz E.; Baganoff, Frederick K.; Barriere, Nicolas M.; Bodaghee, Arash; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Grefenstette, Brian W.; Hailey, Charles J.; Harrison, Fiona A.; Hong, JaeSub; Madsen, Kristin K.; Mori, Kaya; Nynka, Melania; Stern, Daniel; Zhang, William W.

    2014-01-01

    The Arches cluster is a young, densely packed massive star cluster in our Galaxy that shows a high level of star formation activity. The nature of the extended non-thermal X-ray emission around the cluster remains unclear. The observed bright Fe K(alpha) line emission at 6.4 keV from material that is neutral or in a low ionization state can be produced either by X-ray photoionization or by cosmic-ray particle bombardment or both. In this paper, we report on the first detection of the extended emission around the Arches cluster above 10 keV with the NuSTAR mission, and present results on its morphology and spectrum. The spatial distribution of the hard X-ray emission is found to be consistent with the broad region around the cluster where the 6.4 keV line is observed. The interpretation of the hard X-ray emission within the context of the X-ray reflection model puts a strong constraint on the luminosity of the possible illuminating hard X-ray source. The properties of the observed emission are also in broad agreement with the low-energy cosmic-ray proton excitation scenario. Key words: cosmic rays - Galaxy: center - ISM: general - X-rays: individual (Arches cluster)

  11. The contribution of galaxy clusters to the soft X-ray background

    Science.gov (United States)

    Blanchard, A.; Wachter, K.; Evrard, A. E.; Silk, Joseph

    1992-01-01

    The present paper examines models for the expected contribution to the X-ray background (XRB) from clusters of galaxies in a flat universe with a spectrum of fluctuations corresponding to the standard cold dark matter picture and for a power-law spectrum P(k) varies as k sup n with n = -2. A self-similar scaling model for clusters proposed by Kaiser (1986) is presented, along with several variants. Photon statistics from synthesized maps of deep Einstein fields show a granularity similar to that deduced by Hamilton and Helfand (1987) from the Einstein data but overproduces by a large factor the number of discrete sources observed as clusters, and the fluctuation limit derived from the recent correlation analyses of the background. Two alternative models are designed to be consistent with the local luminosity function data; for these, expected deep images for the Rosat satellite are generated. Clusters of galaxies should be a significant source of background at energies around 2 keV, and it is proposed that clusters of galaxies contribute up to 30 percent of the unresolved component.

  12. The cluster charge identification in the GEM detector for fusion plasma imaging by soft X-ray diagnostics

    Science.gov (United States)

    Czarski, T.; Chernyshova, M.; Malinowski, K.; Pozniak, K. T.; Kasprowicz, G.; Kolasinski, P.; Krawczyk, R.; Wojenski, A.; Zabolotny, W.

    2016-11-01

    The measurement system based on gas electron multiplier detector is developed for soft X-ray diagnostics of tokamak plasmas. The multi-channel setup is designed for estimation of the energy and the position distribution of an X-ray source. The focal measuring issue is the charge cluster identification by its value and position estimation. The fast and accurate mode of the serial data acquisition is applied for the dynamic plasma diagnostics. The charge clusters are counted in the space determined by 2D position, charge value, and time intervals. Radiation source characteristics are presented by histograms for a selected range of position, time intervals, and cluster charge values corresponding to the energy spectra.

  13. The cluster charge identification in the GEM detector for fusion plasma imaging by soft X-ray diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Czarski, T., E-mail: tomasz.czarski@ifpilm.pl; Chernyshova, M.; Malinowski, K. [Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw (Poland); Pozniak, K. T.; Kasprowicz, G.; Kolasinski, P.; Krawczyk, R.; Wojenski, A.; Zabolotny, W. [Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warsaw (Poland)

    2016-11-15

    The measurement system based on gas electron multiplier detector is developed for soft X-ray diagnostics of tokamak plasmas. The multi-channel setup is designed for estimation of the energy and the position distribution of an X-ray source. The focal measuring issue is the charge cluster identification by its value and position estimation. The fast and accurate mode of the serial data acquisition is applied for the dynamic plasma diagnostics. The charge clusters are counted in the space determined by 2D position, charge value, and time intervals. Radiation source characteristics are presented by histograms for a selected range of position, time intervals, and cluster charge values corresponding to the energy spectra.

  14. Scaling Relations and X-ray Properties of Moderate-Luminosity Galaxy Clusters from 0.3 < z < 0.6 with XMM-Newton

    CERN Document Server

    Connor, Thomas; Sun, Ming; Hoekstra, Henk; Mahdavi, Andisheh; Conselice, Christopher J; McNamara, Brian

    2014-01-01

    We present new X-ray temperatures and improved X-ray luminosity estimates for 15 new and archival XMM-Newton observations of galaxy clusters at intermediate redshift with mass and luminosities near the galaxy group/cluster division (M2500 < $2.4\\times 10^{14} h_{70}^{-1} M_\\odot$, L < $2\\times 10^{44}$ erg $s^{-1}$, 0.3< z < 0.6). These clusters have weak-lensing mass measurements based on Hubble Space Telescope observations of clusters representative of an X-ray selected sample (the ROSAT 160SD survey). The angular resolution of XMM-Newton allows us to disentangle the emission of these galaxy clusters from nearby point sources, which significantly contaminated previous X-ray luminosity estimates for six of the fifteen clusters. We extend cluster scaling relations between X-ray luminosity, temperature, and weak-lensing mass for low-mass, X-ray-selected clusters out to redshift $\\approx$0.45. These relations are important for cosmology and the astrophysics of feedback in galaxy groups and clusters....

  15. The XMM Cluster Survey: The Halo Occupation Number of BOSS galaxies in X-ray clusters

    CERN Document Server

    Mehrtens, Nicola; Nichol, Robert C; Collins, Chris A; Sahlen, Martin; Rooney, Philip J; Mayers, Julian A; Bermeo-Hernandez, A; Bristow, Martyn; Capozzi, Diego; Christodoulou, L; Comparat, Johan; Hilton, Matt; Hoyle, Ben; Kay, Scott T; Liddle, Andrew R; Mann, Robert G; Masters, Karen; Miller, Christopher J; Parejko, John K; Prada, Francisco; Ross, Ashley J; Schneider, Donald P; Stott, John P; Streblyanska, Alina; Viana, Pedro T P; White, Martin; Wilcox, Harry; Zehavi, Idit

    2015-01-01

    We present a direct measurement of the mean halo occupation distribution (HOD) of galaxies taken from the eleventh data release (DR11) of the Sloan Digital Sky Survey-III Baryon Acoustic Oscillation Survey (BOSS). The HOD of BOSS low-redshift (LOWZ: $0.2 < z < 0.4$) and Constant-Mass (CMASS: $0.43 X-ray-selected galaxy clusters drawn from the XMM Cluster Survey (XCS). Halo masses are determined for each galaxy cluster based on X-ray temperature measurements, and range between ${\\rm log_{10}} (M_{180}/M_{\\odot}) = 13-15$, encompassing the mass range of the `one-halo' term. Our directly-measured HODs are consistent with the HOD-model fits inferred via the galaxy-clustering analyses of Parejko et al. (2013) for the BOSS LOWZ sample and White et al. (2011) for the BOSS CMASS sample. We determine a best-fit alpha-index of 0.91$\\pm$0.08 and $1.27^{+0.03}_{-0.04}$ for the CMASS and LOWZ HOD, respectively. This result p...

  16. The XMM Cluster Survey: the halo occupation number of BOSS galaxies in X-ray clusters

    Science.gov (United States)

    Mehrtens, Nicola; Romer, A. Kathy; Nichol, Robert C.; Collins, Chris A.; Sahlén, Martin; Rooney, Philip J.; Mayers, Julian A.; Bermeo-Hernandez, A.; Bristow, Martyn; Capozzi, Diego; Christodoulou, L.; Comparat, Johan; Hilton, Matt; Hoyle, Ben; Kay, Scott T.; Liddle, Andrew R.; Mann, Robert G.; Masters, Karen; Miller, Christopher J.; Parejko, John K.; Prada, Francisco; Ross, Ashley J.; Schneider, Donald P.; Stott, John P.; Streblyanska, Alina; Viana, Pedro T. P.; White, Martin; Wilcox, Harry; Zehavi, Idit

    2016-12-01

    We present a direct measurement of the mean halo occupation distribution (HOD) of galaxies taken from the eleventh data release (DR11) of the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey (BOSS). The HOD of BOSS low-redshift (LOWZ: 0.2 < z < 0.4) and Constant-Mass (CMASS: 0.43 < z < 0.7) galaxies is inferred via their association with the dark matter haloes of 174 X-ray-selected galaxy clusters drawn from the XMM Cluster Survey (XCS). Halo masses are determined for each galaxy cluster based on X-ray temperature measurements, and range between log10(M180/M⊙) = 13 and 15. Our directly measured HODs are consistent with the HOD-model fits inferred via the galaxy-clustering analyses of Parejko et al. for the BOSS LOWZ sample and White et al. for the BOSS CMASS sample. Under the simplifying assumption that the other parameters that describe the HOD hold the values measured by these authors, we have determined a best-fitting alpha-index of 0.91 ± 0.08 and 1.27^{+0.03}_{-0.04} for the CMASS and LOWZ HOD, respectively. These alpha-index values are consistent with those measured by White et al. and Parejko et al. In summary, our study provides independent support for the HOD models assumed during the development of the BOSS mock-galaxy catalogues that have subsequently been used to derive BOSS cosmological constraints.

  17. A SEARCH FOR HYPERLUMINOUS X-RAY SOURCES IN THE XMM-NEWTON SOURCE CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Zolotukhin, I.; Webb, N. A.; Godet, O.; Barret, D. [CNRS, IRAP, 9 av. Colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France); Bachetti, M., E-mail: ivan.zolotukhin@irap.omp.eu [INAF/Osservatorio Astronomico di Cagliari, via della Scienza 5, I-09047 Selargius (Italy)

    2016-02-01

    We present a new method to identify luminous off-nuclear X-ray sources in the outskirts of galaxies from large public redshift surveys, distinguishing them from foreground and background interlopers. Using the 3XMM-DR5 catalog of X-ray sources and the SDSS DR12 spectroscopic sample of galaxies, with the help of this off-nuclear cross-matching technique, we selected 98 sources with inferred X-ray luminosities in the range 10{sup 41} < L{sub X} < 10{sup 44} erg s{sup −1}, compatible with hyperluminous X-ray objects (HLX). To validate the method, we verify that it allowed us to recover known HLX candidates such as ESO 243–49 HLX–1 and M82 X–1. From a statistical study, we conservatively estimate that up to 71 ± 11 of these sources may be foreground- or background sources, statistically leaving at least 16 that are likely to be HLXs, thus providing support for the existence of the HLX population. We identify two good HLX candidates and using other publicly available data sets, in particular the VLA FIRST in radio, UKIRT Infrared Deep Sky Survey in the near-infrared, GALEX in the ultraviolet and Canada–France–Hawaii Telescope Megacam archive in the optical, we present evidence that these objects are unlikely to be foreground or background X-ray objects of conventional types, e.g., active galactic nuclei, BL Lac objects, Galactic X-ray binaries, or nearby stars. However, additional dedicated X-ray and optical observations are needed to confirm their association with the assumed host galaxies and thus secure their HLX classification.

  18. The first low-mass black hole X-ray binary identified in quiescence outside of a globular cluster

    CERN Document Server

    Tetarenko, B E; Arnason, R M; Miller-Jones, J C A; Repetto, S; Heinke, C O; Maccarone, T J; Chomiuk, L; Sivakoff, G R; Strader, J; Kirsten, F; Vlemmings, W

    2016-01-01

    The observed relation between the X-ray and radio properties of low-luminosity accreting black holes has enabled the identification of multiple candidate black hole X-ray binaries (BHXBs) in globular clusters. Here we report an identification of the radio source VLA J213002.08+120904 (aka M15 S2), recently reported in Kirsten et al. 2014, as a BHXB candidate. They showed that the parallax of this flat-spectrum variable radio source indicates a 2.2$^{+0.5}_{-0.3}$ kpc distance, which identifies it as lying in the foreground of the globular cluster M15. We determine the radio characteristics of this source, and place a deep limit on the X-ray luminosity of $\\sim4\\times10^{29}$ erg s$^{-1}$. Furthermore, we astrometrically identify a faint red stellar counterpart in archival Hubble images, with colors consistent with a foreground star; at 2.2 kpc its inferred mass is 0.1-0.2 $M_{\\odot}$. We rule out that this object is a pulsar, neutron star X-ray binary, cataclysmic variable, or planetary nebula, concluding tha...

  19. Improvements in the X-ray luminosity function and constraints on the Cosmological parameters from X-ray luminous clusters

    CERN Document Server

    Del Popolo, A; Lanzafame, G

    2010-01-01

    We show how to improve constraints on \\Omega_m, \\sigma_8, and the dark-energy equation-of-state parameter, w, obtained by Mantz et al. (2008) from measurements of the X-ray luminosity function of galaxy clusters, namely MACS, the local BCS and the REFLEX galaxy cluster samples with luminosities L> 3 \\times 10^{44} erg/s in the 0.1--2.4 keV band. To this aim, we use Tinker et al. (2008) mass function instead of Jenkins et al. (2001) and the M-L relationship obtained from Del Popolo (2002) and Del Popolo et al. (2005). Using the same methods and priors of Mantz et al. (2008), we find, for a \\Lambda$CDM universe, \\Omega_m=0.28^{+0.05}_{-0.04} and \\sigma_8=0.78^{+0.04}_{-0.05}$ while the result of Mantz et al. (2008) gives less tight constraints $\\Omega_m=0.28^{+0.11}_{-0.07}$ and \\sigma_8=0.78^{+0.11}_{-0.13}. In the case of a wCDM model, we find \\Omega_m=0.27^{+0.07}_{-0.06}, $\\sigma_8=0.81^{+0.05}_{-0.06}$ and $w=-1.3^{+0.3}_{-0.4}$, while in Mantz et al. (2008) they are again less tight \\Omega_m=0.24^{+0.15}_...

  20. The Radiation Dose Determination of the Pulsed X-ray Source

    Science.gov (United States)

    Miloichikova, I.; Stuchebrov, S.; Zhaksybayeva, G.; Wagner, A.

    2014-10-01

    In this paper the radiation dose measurement technique of the pulsed X-ray source RAP-160-5 is described. The dose rate measurement results from the pulsed X-ray beams at the different distance between the pulsed X-ray source focus and the detector obtained with the help of the thermoluminescent detectors DTL-02, the universal dosimeter UNIDOS E equipped with the plane-parallel ionization chamber type 23342, the dosimeter-radiometer DKS-96 and the radiation dosimeter AT 1123 are demonstrated. The recommendations for the dosimetry measurements of the pulsed X-ray generator RAP-160-5 under different radiation conditions are proposed.

  1. LUX - A recirculating linac-based ultrafast X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Green, M.A.; Heimann, P.; Leone, S.R.; Lidia, S.; Li, D.; Parmigiani, F.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Zholents, A.

    2003-08-01

    We describe the design of a proposed source of ultra-fast synchrotron radiation x-ray pulses based on a recirculating superconducting linac, with an integrated array of ultrafast laser systems. The source produces x-ray pulses with duration of 10-50 fs at a 10 kHz repetition rate, with tunability from EUV to hard x-ray regimes, and optimized for the study of ultra-fast dynamics. A high-brightness rf photocathode provides electron bunches. An injector linac accelerates the beam to the 100 MeV range, and is followed by four passes through a 700 MeV recirculating linac. Ultrafast hard x-ray pulses are obtained by a combination of electron bunch manipulation, transverse temporal correlation of the electrons, and x-ray pulse compression. EUV and soft x-ray pulses as short as 10 fs are generated in a harmonic-cascade free electron laser scheme.

  2. Aerogel Cherenkov detector for characterizing the intense flash x-ray source, Cygnus, spectrum

    Science.gov (United States)

    Kim, Y.; Herrmann, H. W.; McEvoy, A. M.; Young, C. S.; Hamilton, C.; Schwellenbach, D. D.; Malone, R. M.; Kaufman, M. I.; Smith, A. S.

    2016-11-01

    An aerogel Cherenkov detector is proposed to measure the X-ray energy spectrum from the Cygnus—intense flash X-ray source operated at the Nevada National Security Site. An array of aerogels set at a variety of thresholds between 1 and 3 MeV will be adequate to map out the bremsstrahlung X-ray production of the Cygnus, where the maximum energy of the spectrum is normally around 2.5 MeV. In addition to the Cherenkov radiation from aerogels, one possible competing light-production mechanism is optical transition radiation (OTR), which may be significant in aerogels due to the large number of transitions from SiO2 clusters to vacuum voids. To examine whether OTR is a problem, four aerogel samples were tested using a mono-energetic electron beam (varied in the range of 1-3 MeV) at NSTec Los Alamos Operations. It was demonstrated that aerogels can be used as a Cherenkov medium, where the rate of the light production is about two orders magnitude higher when the electron beam energy is above threshold.

  3. The evolution of X-ray galaxy clusters as a constraint of Omega(0)

    DEFF Research Database (Denmark)

    Oukbir, J.

    1998-01-01

    Clusters of galaxies are rare objects and as such, their properties are particularly sensitive to the underlying density fluctuations. Therefore, the cluster population provides very stringent constraints on models of galaxy formation. We here show how self-consistent modeling of X-ray galaxy dus...

  4. Cross Correlations of X-ray and Optically Selected Clusters With Near Infrared and Optical Galaxies

    CERN Document Server

    Sánchez, A G; Böhringer, H; Schücker, P; Sanchez, Ariel G.; Lambas, Diego G.; Boehringer, Hans; Schuecker, Peter

    2005-01-01

    We compute the real-space cluster-galaxy cross-correlation xi_cg(r) using the ROSAT-ESO Flux Limited X-ray (REFLEX) cluster survey, a group catalogue constructed from the final version of the 2dFGRS, and galaxies extracted from 2MASS and APM surveys. This first detailed calculation of the cross-correlation for X-ray clusters and groups, is consistent with previous works and shows that xi_cg(r) can not be described by a single power law. We analyse the clustering dependence on the cluster X-ray luminosity L_X and virial mass M_vir thresholds as well as on the galaxy limiting magnitude. We also make a comparison of our results with those obtained for the halo-mass cross-correlation function in a LambdaCDM N-body simulation to infer the scale dependence of galaxy bias around clusters. Our results indicate that the distribution of galaxies shows a significant anti-bias at highly non-linear small cluster-centric distances (b_cg(r) ~ 0.7), irrespective of the group/cluster virial mass or X-ray luminosity and galaxy...

  5. RF Phase Stability and Electron Beam Characterization for the PLEIADES Thomson X-Ray Source

    Energy Technology Data Exchange (ETDEWEB)

    Brown, W J; Hartemann, F V; Tremaine, A M; Springer, P T; Le Sage, G P; Barty, C P J; Rosenzweig, J B; Crane, J K; Cross, R R; Fittinghoff, D N; Gibson, D J; Slaughter, D R; Anderson, S

    2002-10-16

    We report on the performance of an S-band RF photocathode electron gun and accelerator for operation with the PLEIADES Thomson x-ray source at LLNL. To produce picosecond, high brightness x-ray pulses, picosecond timing, terahertz bandwidth diagnostics, and RF phase control are required. Planned optical, RF, x-ray and electron beam measurements to characterize the dependence of electron beam parameters and synchronization on RF phase stability are presented.

  6. A dedicated synchrotron light source for ultrafast x-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.; DeSantis, S.; Hartman, N.; Heimann, P.; Lafever, R.; Li, D.; Padmore, H.; Rimmer, R.; Robinson, K.E.; Schoenlein, R.; Tanabe, J.; Wang, S.; Zholents, A.; Kairan, D.

    2001-06-16

    We describe a proposed femtosecond synchrotron radiation x-ray source based on a flat-beam RF gun and a recirculating superconducting linac that provides beam to an array of undulators and bend magnets. X-ray pulse durations of <100 fs at a 10 kHz repetition rate are obtained by a combination of electron pulse compression, transverse temporal correlation of the electrons, and x-ray pulse compression.

  7. The soft quiescent spectrum of the transiently accreting 11-Hz X-ray pulsar in the globular cluster Terzan 5

    NARCIS (Netherlands)

    N. Degenaar; R. Wijnands

    2011-01-01

    We report on the quiescent X-ray properties of the recently discovered transiently accreting 11-Hz X-ray pulsar in the globular cluster Terzan 5. Using two archival Chandra observations, we demonstrate that the quiescent spectrum of this neutron star low-mass X-ray binary is soft and can be fit to a

  8. Multiple ionization of atom clusters by intense soft X-rays from a free-electron laser.

    Science.gov (United States)

    Wabnitz, H; Bittner, L; de Castro, A R B; Döhrmann, R; Gürtler, P; Laarmann, T; Laasch, W; Schulz, J; Swiderski, A; von Haeften, K; Möller, T; Faatz, B; Fateev, A; Feldhaus, J; Gerth, C; Hahn, U; Saldin, E; Schneidmiller, E; Sytchev, K; Tiedtke, K; Treusch, R; Yurkov, M

    2002-12-05

    Intense radiation from lasers has opened up many new areas of research in physics and chemistry, and has revolutionized optical technology. So far, most work in the field of nonlinear processes has been restricted to infrared, visible and ultraviolet light, although progress in the development of X-ray lasers has been made recently. With the advent of a free-electron laser in the soft-X-ray regime below 100 nm wavelength, a new light source is now available for experiments with intense, short-wavelength radiation that could be used to obtain deeper insights into the structure of matter. Other free-electron sources with even shorter wavelengths are planned for the future. Here we present initial results from a study of the interaction of soft X-ray radiation, generated by a free-electron laser, with Xe atoms and clusters. We find that, whereas Xe atoms become only singly ionized by the absorption of single photons, absorption in clusters is strongly enhanced. On average, each atom in large clusters absorbs up to 400 eV, corresponding to 30 photons. We suggest that the clusters are heated up and electrons are emitted after acquiring sufficient energy. The clusters finally disintegrate completely by Coulomb explosion.

  9. The BMW (Brera-Multiscale-Wavelet) Catalogue of Serendipitous X-ray Sources

    CERN Document Server

    Lazzati, D; Covino, S; Israel, G L; Guzzo, L; Mignani, R P; Moretti, A; Panzera, M R; Tagliaferri, G

    2000-01-01

    In collaboration with the Observatories of Palermo and Rome and the SAX-SDC we are constructing a multi-site interactive archive system featuring specific analysis tools. In this context we developed a detection algorithm based on the Wavelet Transform (WT) and performed a systematic analysis of all ROSAT-HRI public data (~3100 observations +1000 to come). The WT is specifically suitable to detect and characterize extended sources while properly detecting point sources in very crowded fields. Moreover, the good angular resolution of HRI images allows the source extension and position to be accurately determined. This effort has produced the BMW (Brera Multiscale Wavelet) catalogue, with more than 19,000 sources detected at the 4.2 sigma level. For each source detection we have information on the X-ray flux and extension, allowing for instance to select complete samples of extended X-ray sources such as candidate clusters of galaxies or SNR's. Here we present an overview of first results from several undergoin...

  10. The BMW (Brera-Multiscale-Wavelet) Catalogue of Serendipitous X-Ray Sources

    Science.gov (United States)

    Lazzati, Davide; Campana, Sergio; Covino, Stefano; Israel, Gian L.; Guzzo, Luigi; Mignani, Roberto; Moretti, Alberto; Panzera, Maria R.; Tagliaferri, Gianpiero

    In collaboration with the Observatories of Palermo and Rome and the SAX-SDC we are constructing a multi-site interactive archive system featuring specific analysis tools. In this context we developed a detection algorithm based on the Wavelet Transform (WT) and performed a systematic analysis of all ROSATHRI public data (˜3100 observations +1000 to come). The WT is specifically suitable to detect and characterize extended sources while properly detecting point sources in very crowded fields. Moreover, the good angular resolution of HRI images allows the source extension and position to be accurately determined. This effort has produced the BMW (Brera Multiscale Wavelet) catalogue, with more than 19,000 sources detected at the ˜4.2σ level. For each source detection we have information on the X-ray flux and extension, allowing for instance to select complete samples of extended X-ray sources such as candidate clusters of galaxies or SNR's. Details about the detection algorithm and the catalogue can be found in Lazzati et al. 1999 and Campana et al. 1999. Here we shall present an overview of first results from several undergoing projects which make use of the BMW catalogue.

  11. Development and characterization of a laser-based hard x-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Tillman, C.

    1996-11-01

    A laser-produced plasma was generated by focusing 100 fs laser pulses, with an energy of 150 mJ, onto metal targets. The laser intensity was expected to reach 10{sup 17} W/cm{sup -2}. Radiation was emitted from the created plasma, with photon energies up to the MeV region. The laser-based X-ray source was optimized, with the purpose of making it a realistic source of hard X-rays (>10 keV). Dedicated equipment was developed for efficient generation and utilization of the hard X-rays. The X-ray source was characterized with respect to its spatial extent and the X-ray yield. Measurements were made of the spectral distribution, by the use of single-photon-counting detectors in different geometries, crystal spectrometers and dose measurements in combination with absorption filters. Ablation of the target material in the laser produced plasma was investigated. Imaging applications have been demonstrated, including ultrafast (picosecond) X-ray imaging, magnification imaging of up to x80, differential imaging in the spectral domain, and imaging of various biological and technical objects. The biological response of ultra-intense X-ray pulses was assessed in cell-culture exposures. The results indicate that the biological response from ultra-intense X-ray exposures is similar to the response with conventional X-ray tubes. 82 refs., 14 figs.

  12. Transmission type flat-panel X-ray source using ZnO nanowire field emitters

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Daokun; Song, Xiaomeng; Zhang, Zhipeng; Chen, Jun, E-mail: stscjun@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou 510275 (China); School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Li, Ziping [The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510275 (China); She, Juncong; Deng, Shaozhi; Xu, Ningsheng [State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou 510275 (China); School of Microelectronics, Sun Yat-sen University, Guangzhou 510275 (China)

    2015-12-14

    A transmission type flat-panel X-ray source in diode structure was fabricated. Large-scale patterned ZnO nanowires grown on a glass substrate by thermal oxidation were utilized as field emitters, and tungsten thin film coated on silica glass was used as the transmission anode. Uniform distribution of X-ray generation was achieved, which benefited from the uniform electron emission from ZnO nanowires. Self-ballasting effect induced by the intrinsic resistance of ZnO nanowire and decreasing of screening effect caused by patterned emitters account for the uniform emission. Characteristic X-ray peaks of W-L lines and bremsstrahlung X-rays have been observed under anode voltages at a range of 18–20 kV, the latter of which were the dominant X-ray signals. High-resolution X-ray images with spatial resolution less than 25 μm were obtained by the flat-panel X-ray source. The high resolution was attributed to the small divergence angle of the emitted X-rays from the transmission X-ray source.

  13. Testing X-ray Measurements of Galaxy Cluster Outskirts with Cosmological Simulations

    CERN Document Server

    Avestruz, Camille; Nagai, Daisuke; Vikhlinin, Alexey

    2014-01-01

    The study of galaxy cluster outskirts has emerged as one of the new frontiers in extragalactic astrophysics and cosmology with the advent of new observations in X-ray and microwave. However, the thermodynamic properties and chemical enrichment of this diffuse and azimuthally asymmetric component of the intra-cluster medium are still not well understood. This work, for the first time, systematically explores potential observational biases in these regions. To assess X-ray measurements of galaxy cluster properties at large radii ($>{R}_{500c}$), we use mock Chandra analyses of cosmological galaxy cluster simulations. The pipeline is identical to that used for Chandra observations, but the biases discussed in this paper are relevant for all X-ray observations outside of ${R}_{500c}$. We find the following from our analysis: (1) filament regions can contribute as much as a factor of 3 to the emission measure, (2) X-ray temperatures and metal abundances from model fitted mock X-ray spectra respectively vary to the...

  14. Stereoscopic observations of a solar flare hard X-ray source in the high corona

    Science.gov (United States)

    Kane, S. R.; Mctiernan, J.; Loran, J.; Fenimore, E. E.; Klebesadel, R. W.; Laros, J. G.

    1992-01-01

    The vertical structure of the impulsive and gradual hard X-ray sources in high coronae and the characteristics of the impulsive soft X-ray emission are investigated on the basis of PVE, ICE, and GOES observations of the energetic flare on February 16, 1984. The average photon spectra observed by these instruments during the impulsive and gradual hard X-ray bursts are summarized. A comparison of these unocculted and partially occulted spectra shows that the sources of the impulsive hard X-ray (greater than about 25 keV) and impulsive soft X-ray (2-5 keV) emissions in this flare extended to coronal altitudes greater than about 200,000 km above the photosphere. At about 100 keV, the ratio of the coronal source brightness to the total source brightness was 0.001 during the impulsive phase and less than about 0.01 during the gradual hard X-ray burst. The sources of the gradual hard X-ray burst and gradual soft X-ray burst were almost completely occulted, indicating that these sources were located at heights less than 200,000 km above the photosphere.

  15. THREE NEW GALACTIC CENTER X-RAY SOURCES IDENTIFIED WITH NEAR-INFRARED SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    DeWitt, Curtis [Department of Physics, University of California, Davis, CA 95616 (United States); Bandyopadhyay, Reba M.; Eikenberry, Stephen S.; Sarajedini, Ata [Department of Astronomy, University of Florida, 211 Bryant Space Center, P.O. Box 112055, Gainesville, FL 32611 (United States); Sellgren, Kris [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Blum, Robert; Olsen, Knut [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Bauer, Franz E., E-mail: curtis.n.dewitt@nasa.gov [Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile)

    2013-11-01

    We have conducted a near-infrared spectroscopic survey of 47 candidate counterparts to X-ray sources discovered by the Chandra X-Ray Observatory near the Galactic center (GC). Though a significant number of these astrometric matches are likely to be spurious, we sought out spectral characteristics of active stars and interacting binaries, such as hot, massive spectral types or emission lines, in order to corroborate the X-ray activity and certify the authenticity of the match. We present three new spectroscopic identifications, including a Be high-mass X-ray binary (HMXB) or a γ Cassiopeiae (Cas) system, a symbiotic X-ray binary, and an O-type star of unknown luminosity class. The Be HMXB/γ Cas system and the symbiotic X-ray binary are the first of their classes to be spectroscopically identified in the GC region.

  16. DEVELOPMENT OF NEW MID-INFRARED ULTRAFAST LASER SOURCES FOR COMPACT COHERENT X-RAY SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Sterling Backus

    2012-05-14

    In this project, we proposed to develop laser based mid-infrared lasers as a potentially robust and reliable source of ultrafast pulses in the mid-infrared region of the spectrum, and to apply this light source to generating bright, coherent, femtosecond-to-attosecond x-ray beams.

  17. A Chandra X-ray study of the young star cluster NGC 6231: low-mass population and initial mass function

    CERN Document Server

    Damiani, F; Sciortino, S

    2016-01-01

    NGC6231 is a massive young star cluster, near the center of the Sco OB1 association. While its OB members are well studied, its low-mass population has received little attention. We present high-spatial resolution Chandra ACIS-I X-ray data, where we detect 1613 point X-ray sources. Our main aim is to clarify global properties of NGC6231 down to low masses through a detailed membership assessment, and to study the cluster stars' spatial distribution, the origin of their X-ray emission, the cluster age and formation history, and initial mass function. We use X-ray data, complemented by optical/IR data, to establish cluster membership. The spatial distribution of different stellar subgroups also provides highly significant constraints on cluster membership, as does the distribution of X-ray hardness. We perform spectral modeling of group-stacked X-ray source spectra. We find a large cluster population down to ~0.3 Msun (complete to ~1 Msun), with minimal non-member contamination, with a definite age spread (1-8 ...

  18. Development of a multilayer mirror for high-intensity monochromatic x-ray using lab-based x-ray source.

    Science.gov (United States)

    Nguyen, Thanh-hai; Song, Seonggeun; Jung, Jin-Ho; Jeon, Insu

    2012-09-15

    A parabolic, multilayer x-ray mirror, which can be used with a general lab-based x-ray source, was designed and fabricated. A glass substrate for the mirror was fabricated. Its surface was determined by following the rotation of a parabolic curve and was polished precisely. On the substrate surface, six W/Al bilayers were deposited to form the multilayer mirror. The effects of the mirror on x-ray images were investigated based on the calculated modulation transfer function (MTF) and image intensity values. Higher MTF and intensity values of an x-ray image were obtained using the mirror.

  19. Time-resolved Rocking Curve Measurement Method using Laboratory X-ray Source

    OpenAIRE

    林, 雄二郎; 佐藤, 真伸; 古賀, 三井; 佃, 昇; 蔵元, 英一

    2005-01-01

    Fast x-ray detectors and fast signal processing devices have enabled to measure time dependence of x-ray diffraction intensity. Using a fast x-ray detection system, we have developed a time-resolved measurement method of rocking curves with a laboratory x-ray source. The method has been demonstrated for time-resolved rocking curves from an ultrasound-vibrated silicon crystal in MHz range. The measured rocking curves have been consistent with simulated curves based on the dynamical diffraction...

  20. Source effects in analyzer-based X-ray phase contrast imaging with conventional sources

    Energy Technology Data Exchange (ETDEWEB)

    Hoennicke, M. G. [Universidade Federal da Integracao Latino-Americana, 85867-970 Foz do Iguacu, PR (Brazil); Manica, J. [Universidade Estadual do Oeste do Parana, 85867-970 Foz do Iguacu, PR (Brazil); Mazzaro, I.; Cusatis, C. [LORXI, Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19091, 81531-990 Curitiba, PR (Brazil); Huang, X.-R. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2012-11-15

    Several recent papers have shown the implementation of analyzer based X-ray phase contrast imaging (ABI) with conventional X-ray sources. The high flux is always a requirement to make the technique useful for bio-medical applications. Here, we present and discuss three important parameters, which need to be taken into account, when searching for the high flux ABI: anisotropic magnification, double image, and source size spread due to intrinsic dispersive diffraction by asymmetrically cut crystals. These parameters, if not well optimized, may cause important features in the acquired images which can mislead the interpretation. A few ways to minimize these effects are implemented and discussed, including some experimental results.

  1. S-band linac-based X-ray source with {pi}/2-mode electron linac

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, Abhay, E-mail: abhay@post.kek.jp [Department of Accelerator Science, School of High Energy Accelerator Science, Graduate University for Advanced Studies, Shonan International Village, Hayama, Miura, Kanagawa 240-0193 (Japan); Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Araki, Sakae [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Dixit, Tanuja [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Fukuda, Masafumi [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Krishnan, R; Pethe, Sanjay [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Sakaue, Kazuyuki [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan); Terunuma, Nobuhiro; Urakawa, Junji [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Washio, Masakazu [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan)

    2011-05-01

    The activities with the compact X-ray source are attracting more attention, particularly for the applications of the source in medical fields. We propose the fabrication of a compact X-ray source using the SAMEER electron linear accelerator and the KEK laser undulator X-ray source (LUCX) technologies. The linac developed at SAMEER is a standing wave side-coupled S-band linac operating in the {pi}/2 mode. In the proposed system, a photocathode RF gun will inject bunches of electrons in the linac to accelerate and achieve a high-energy, low-emittance beam. This beam will then interact with the laser in the laser cavity to produce X-rays of a type well suited for various applications. The side-coupled structure will make the system more compact, and the {pi}/2 mode of operation will enable a high repetition rate operation, which will help to increase the X-ray yield.

  2. On the black hole masses in ultra-luminous X-ray sources

    Science.gov (United States)

    Zhou, Xin-Lin

    2015-05-01

    Ultra-luminous X-ray sources (ULXs) are off-nuclear X-ray sources in nearby galaxies with X-ray luminosities ⩾ 1039 erg s-1. The measurement of the black hole (BH) masses of ULXs is a long-standing problem. Here we estimate BH masses in a sample of ULXs with XMM-Newton observations using two different mass indicators, the X-ray photon index and X-ray variability amplitude based on the correlations established for active galactic nuclei (AGNs). The BH masses estimated from the two methods are compared and discussed. We find that some extreme high-luminosity (LX > 5 ×1040 erg s-1) ULXs contain the BH of 104-105 M⊙ . The results from X-ray variability amplitude are in conflict with those from X-ray photon indices for ULXs with lower luminosities. This suggests that these ULXs generally accrete at rates different from those of X-ray luminous AGNs, or they have different power spectral densities of X-ray variability. We conclude that most of ULXs accrete at super-Eddington rate, thus harbor stellar-mass BH.

  3. CHANDRA ACIS Survey of X-Ray Point Sources: The Source Catalog

    Science.gov (United States)

    Wang, Song; Liu, Jifeng; Qiu, Yanli; Bai, Yu; Yang, Huiqin; Guo, Jincheng; Zhang, Peng

    2016-06-01

    The Chandra archival data is a valuable resource for various studies on different X-ray astronomy topics. In this paper, we utilize this wealth of information and present a uniformly processed data set, which can be used to address a wide range of scientific questions. The data analysis procedures are applied to 10,029 Advanced CCD Imaging Spectrometer observations, which produces 363,530 source detections belonging to 217,828 distinct X-ray sources. This number is twice the size of the Chandra Source Catalog (Version 1.1). The catalogs in this paper provide abundant estimates of the detected X-ray source properties, including source positions, counts, colors, fluxes, luminosities, variability statistics, etc. Cross-correlation of these objects with galaxies shows that 17,828 sources are located within the D 25 isophotes of 1110 galaxies, and 7504 sources are located between the D 25 and 2D 25 isophotes of 910 galaxies. Contamination analysis with the log N-log S relation indicates that 51.3% of objects within 2D 25 isophotes are truly relevant to galaxies, and the “net” source fraction increases to 58.9%, 67.3%, and 69.1% for sources with luminosities above 1037, 1038, and 1039 erg s-1, respectively. Among the possible scientific uses of this catalog, we discuss the possibility of studying intra-observation variability, inter-observation variability, and supersoft sources (SSSs). About 17,092 detected sources above 10 counts are classified as variable in individual observation with the Kolmogorov-Smirnov (K-S) criterion (P K-S < 0.01). There are 99,647 sources observed more than once and 11,843 sources observed 10 times or more, offering us a wealth of data with which to explore the long-term variability. There are 1638 individual objects (˜2350 detections) classified as SSSs. As a quite interesting subclass, detailed studies on X-ray spectra and optical spectroscopic follow-up are needed to categorize these SSSs and pinpoint their properties. In addition

  4. Recent results of X-ray observations from OSO-7 and SAS-3

    Science.gov (United States)

    Clark, G. W.

    1978-01-01

    Recent observations bearing on the nature of compact X-ray sources obtained from the MIT instruments aboard OSO-7 and SAS-3 are discussed. Results on the X-ray sky survey, new ultralow-energy X-ray sources, X-ray sources in globular clusters, slow X-ray pulsars, and variability and position of compact X-ray sources in Cen A are discussed. Descriptions of the satellite-borne X-ray instruments are provided.

  5. The X-ray spectral evolution of the ultraluminous X-ray source Holmberg IX X-1

    CERN Document Server

    Luangtip, W; Done, C

    2016-01-01

    We present a new analysis of X-ray spectra of the archetypal ultraluminous X-ray source (ULX) Holmberg IX X-1 obtained by the Swift, XMM-Newton and NuSTAR observatories. This ULX is a persistent source, with a typical luminosity of ~10^40 erg s^-1, that varied by a factor of 4 - 5 over eight years. We find that its spectra tend to evolve from relatively flat or two-component spectra in the medium energy band (1-6 keV), at lower luminosities, to a spectrum that is distinctly curved and disc-like at the highest luminosities, with the peak energy in the curved spectrum tending to decrease with increased luminosity. We argue that the spectral evolution of the ULX can be explained by super-Eddington accretion models, where in this case we view the ULX down the evacuated funnel along its rotation axis, bounded by its massive radiatively driven wind. The spectral changes then originate in enhanced geometric beaming as the accretion rate increases and wind funnel narrows, causing the scattered flux from the central r...

  6. Non-parametric method for measuring gas inhomogeneities from X-ray observations of galaxy clusters

    CERN Document Server

    Morandi, Andrea; Cui, Wei

    2013-01-01

    We present a non-parametric method to measure inhomogeneities in the intracluster medium (ICM) from X-ray observations of galaxy clusters. Analyzing mock Chandra X-ray observations of simulated clusters, we show that our new method enables the accurate recovery of the 3D gas density and gas clumping factor profiles out to large radii of galaxy clusters. We then apply this method to Chandra X-ray observations of Abell 1835 and present the first determination of the gas clumping factor from the X-ray cluster data. We find that the gas clumping factor in Abell 1835 increases with radius and reaches ~2-3 at r=R_{200}. This is in good agreement with the predictions of hydrodynamical simulations, but it is significantly below the values inferred from recent Suzaku observations. We further show that the radially increasing gas clumping factor causes flattening of the derived entropy profile of the ICM and affects physical interpretation of the cluster gas structure, especially at the large cluster-centric radii. Our...

  7. X-ray and optical spectroscopy of the massive young open cluster IC1805

    CERN Document Server

    Rauw, Gregor

    2016-01-01

    Very young open clusters are ideal places to study the X-ray properties of a homogeneous population of early-type stars. In this respect, the IC1805 open cluster is very interesting as it hosts the O4If$^+$ star HD15570 thought to be in an evolutionary stage intermediate between a normal O-star and a Wolf-Rayet star. Such a star could provide a test for theoretical models aiming at explaining the empirical scaling relation between the X-ray and bolometric luminosities of O-type stars. We have observed IC1805 with XMM-Newton and further collected optical spectroscopy of some of the O-star members of the cluster. The optical spectra allow us to revisit the orbital solutions of BD+60$^{\\circ}$ 497 and HD15558, and provide the first evidence of binarity for BD+60$^{\\circ}$ 498. X-ray emission from colliding winds does not appear to play an important role among the O-stars of IC1805. Notably, the X-ray fluxes do not vary significantly between archival X-ray observations and our XMM-Newton pointing. The very fast r...

  8. Near-infrared counterparts of Chandra X-ray sources toward the Galactic Center

    CERN Document Server

    DeWitt, Curtis; Eikenberry, Stephen S; Blum, Robert; Olsen, Knut; Sellgren, Kris; Sarajedini, Ata

    2010-01-01

    The Chandra X-ray Observatory has now discovered nearly 10,000 X-ray point sources in the 2 x 0.8 degree region around the Galactic Center (Muno 2009). The sources are likely to be a population of accreting binaries in the Galactic Center, but little else is known of their nature. We obtained JHKs imaging of the 17'x 17' region around Sgr A*, an area containing 4339 of these X-ray sources, with the ISPI camera on the CTIO 4-m telescope. We cross-correlate the Chandra and ISPI catalogs to find potential IR counterparts to the X-ray sources. The extreme IR source crowding in the field means that it is not possible to establish the authenticity of the matches with astrometry and photometry alone. We find 2137 IR/X-ray astrometrically matched sources: statistically we estimate that our catalog contains 289 +/- 13 true matches to soft X-ray sources and 154 +/- 39 matches to hard X-ray sources. However, the fraction of true counterparts to candidate counterparts for hard sources is just 11 %, compared to 60 % for s...

  9. Broadband X-ray spectra of the ultraluminous x-ray source Holmberg IX X-1 observed with NuSTAR, XMM-Newton, and Suzaku

    DEFF Research Database (Denmark)

    Walton, D. J.; Harrison, F. A.; Grefenstette, B. W.;

    2014-01-01

    We present results from the coordinated broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 performed by NuSTAR, XMM-Newton, and Suzaku in late 2012. These observations provide the first high-quality spectra of Holmberg IX X-1 above 10 keV to date, extending the X...

  10. A hard X-ray study of the ultraluminous X-ray source NGC 5204 X-1 with NuSTAR and XMM-Newton

    DEFF Research Database (Denmark)

    Mukherjee, E. S.; Walton, D. J.; Bachetti, M.;

    2015-01-01

    We present the results from coordinated X-ray observations of the ultraluminous X-ray source NGC 5204 X-1 performed by the Nuclear Spectroscopic Telescope Array and XMM-Newton in early 2013. These observations provide the first detection of NGC 5204 X-1 above 10 keV, extending the broadband...

  11. Soft-X-Ray Projection Lithography Using a High-Repetition-Rate Laser-Induced X-Ray Source for Sub-100 Nanometer Lithography Processes

    NARCIS (Netherlands)

    E. Louis,; F. Bijkerk,; Shmaenok, L.; Voorma, H. J.; van der Wiel, M. J.; Schlatmann, R.; Verhoeven, J.; van der Drift, E. W. J. M.; Romijn, J.; Rousseeuw, B. A. C.; Voss, F.; Desor, R.; Nikolaus, B.

    1993-01-01

    In this paper we present the status of a joint development programme on soft x-ray projection lithography (SXPL) integrating work on high brightness laser plasma sources. fabrication of multilayer x-ray mirrors. and patterning of reflection masks. We are in the process of optimization of a laser-pla

  12. Development of low-energy x-ray fluorescence micro-distribution analysis using a laser plasma x-ray source and multilayer optics?

    NARCIS (Netherlands)

    Stuik, R.; Shmaenok, L. A.; Fledderus, H.; Andreev, S. S.; Shamov, E. A.; Zuev, S. Y.; Salashchenko, N. N.; F. Bijkerk,

    1999-01-01

    A new technique is presented for low-energy X-ray fluorescence micro-distribution analysis of low-Z elements at micrometer spatial resolutions. The technique is based on the use of a laser plasma X-ray source and spherically curved multilayer optics. A large collimator is used to focus the light fro

  13. On the disruption of pulsar and X-ray binaries in globular clusters

    CERN Document Server

    Verbunt, Frank

    2013-01-01

    The stellar encounter rate Gamma has been shown to be strongly correlated with the number of X-ray binaries in clusters and also to the number of radio pulsars. However, the pulsar populations in different clusters show remarkably different characteristics: in some GCs the population is dominated by binary systems, in others by single pulsars and exotic systems that result from exchange encounters. In this paper, we describe a second dynamical parameter for globular clusters, the encounter rate for a single binary, gamma. We find that this parameter provides a good characterization of the differences between the pulsar populations of different globular clusters. The higher gamma is for any particular globular cluster the more isolated pulsars and products of exchange interactions are observed. Furthermore, we also find that slow and "young" pulsars are found almost exclusively in clusters with a high gamma; this suggests that these kinds of objects are formed by the disruption of X-ray binaries, thus halting ...

  14. Monitoring the activity variations of galactic X-ray sources with WATCH on EURECA

    DEFF Research Database (Denmark)

    Brandt, Søren; Lund, N.

    1995-01-01

    sources the observation periods extended over more than 100 days. A number of X-ray transients with durations between one and five days were discovered, and, additionally two long duration X-ray transients (GRS 1915+10 and GRO J0422+32) were active and could be monitored. Towards the end of the mission...

  15. Shielded radiography with a laser-driven MeV-energy X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shouyuan; Golovin, Grigory [Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States); Miller, Cameron [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Haden, Daniel; Banerjee, Sudeep; Zhang, Ping; Liu, Cheng; Zhang, Jun; Zhao, Baozhen [Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States); Clarke, Shaun; Pozzi, Sara [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Umstadter, Donald, E-mail: donald.umstadter@unl.edu [Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States)

    2016-01-01

    We report the results of experimental and numerical-simulation studies of shielded radiography using narrowband MeV-energy X-rays from a compact all-laser-driven inverse-Compton-scattering X-ray light source. This recently developed X-ray light source is based on a laser-wakefield accelerator with ultra-high-field gradient (GeV/cm). We demonstrate experimentally high-quality radiographic imaging (image contrast of 0.4 and signal-to-noise ratio of 2:1) of a target composed of 8-mm thick depleted uranium shielded by 80-mm thick steel, using a 6-MeV X-ray beam with a spread of 45% (FWHM) and 10{sup 7} photons in a single shot. The corresponding dose of the X-ray pulse measured in front of the target is ∼100 nGy/pulse. Simulations performed using the Monte-Carlo code MCNPX accurately reproduce the experimental results. These simulations also demonstrate that the narrow bandwidth of the Compton X-ray source operating at 6 and 9 MeV leads to a reduction of deposited dose as compared to broadband bremsstrahlung sources with the same end-point energy. The X-ray beam’s inherently low-divergence angle (∼mrad) is advantageous and effective for interrogation at standoff distance. These results demonstrate significant benefits of all-laser driven Compton X-rays for shielded radiography.

  16. Pile-up corrections in laser-driven pulsed x-ray sources

    CERN Document Server

    Hernández, Guillermo

    2016-01-01

    A formalism for treating the pile-up produced in laser-driven pulsed x-ray sources has been developed. It allows the direct use of x-ray spectroscopy without artificially decreasing the number of counts in the detector. The influence of the pile-up on the overestimation of temperature parameters is shown up.

  17. The X-ray source content of the XGPS Galactic Plane Survey

    CERN Document Server

    Motch, C; Cropper, M S; Carrera, F; Guillout, P; Pineau, F X; Pakull, M W; Rosen, S; Schwope, A; Tedds, J; Webb, N; Negueruela, I; Watson, M G

    2009-01-01

    We report the results of an optical campaign carried out by the XMM-Newton Survey Science Centre with the specific goal of identifying the brightest X-ray sources in the XMM-Newton Galactic Plane Survey of Hands et al. (2004). In addition to photometric and spectroscopic observations obtained at the ESO-VLT and ESO-3.6m, we used cross-correlations with the 2XMMi, USNO-B1.0, 2MASS and GLIMPSE catalogues to progress the identification process. Active coronae account for 16 of the 30 identified X-ray sources. Many of the identified hard X-ray sources are associated with massive stars emitting at intermediate X-ray luminosities of 10^32-34 erg/s. Among these are a very absorbed likely hyper-luminous star with X-ray/optical spectra and luminosities comparable with those of eta Carina, a new X-ray selected WN8 Wolf-Rayet star, a new Be/X-ray star belonging to the growing class of Gamma-Cas analogs and a possible supergiant X-ray binary of the kind discovered recently by INTEGRAL. One of the sources, XGPS-25 has a c...

  18. Laser-Plasma Sources for Soft-X-Ray Projection Lithography

    NARCIS (Netherlands)

    F. Bijkerk,; Shmaenok, L.; Vanhonk, A.; Bastiaensen, R.; Platonov, Y. Y.; Shevelko, A. P.; Mitrofanov, A. V.; Voss, F.; Desor, R.; Frowein, H.; Nikolaus, B.

    1994-01-01

    Results are reported concerning high-repetition-rate excimer lasers with average powers up to 415 W and their usage for generating laser-plasma soft X-ray sources. A conversion efficiency of laser light into monochromatized soft X-ray radiation of 0.7% at 13.5 nm (2% bandwidth) was achieved using an

  19. Laser-Plasma Sources for Soft-X-Ray Projection Lithography

    NARCIS (Netherlands)

    F. Bijkerk,; Shmaenok, L.; Vanhonk, A.; Bastiaensen, R.; Platonov, Y. Y.; Shevelko, A. P.; Mitrofanov, A. V.; Voss, F.; Desor, R.; Frowein, H.; Nikolaus, B.

    1994-01-01

    Results are reported concerning high-repetition-rate excimer lasers with average powers up to 415 W and their usage for generating laser-plasma soft X-ray sources. A conversion efficiency of laser light into monochromatized soft X-ray radiation of 0.7% at 13.5 nm (2% bandwidth) was achieved using an

  20. The Discovery of a Very Faint X-ray Transient in the Globular Cluster M15

    CERN Document Server

    Heinke, Craig O; Lugger, Phyllis M

    2008-01-01

    We have identified an X-ray transient (hereafter M15 X-3) in the globular cluster M15 from an archival Chandra grating observation. M15 X-3 appears at an X-ray luminosity of 6*10^{33} ergs/s with a spectrum consistent with an absorbed power law of photon index 1.51+-0.14. The object is identifiable in archival Chandra HRC-I observations with an X-ray luminosity of 2-6*10^{31} ergs/s and apparently soft colors, suggesting a neutron star low-mass X-ray binary in quiescence. We also observe it in outburst in a 2007 Chandra HRC-I observation, and in archival 1994-1995 ROSAT HRI observations. We identify a likely optical/UV counterpart with a (possibly transient) UV excess from archival HST data, which suggests a main sequence companion. We argue that M15 X-3's behavior is similar to that of the very faint X-ray transients which have been observed in the Galactic Center. We discuss several explanations for its very low X-ray luminosity, with the assumption that we have detected its companion. M15 X-3's uniquely lo...

  1. Spot size diagnostics for flash radiographic X-ray sources at LAPA

    Institute of Scientific and Technical Information of China (English)

    LI Cheng-Gang; LI Qin; SHI Jin-Shui; DENG Jian-Jun

    2009-01-01

    Spot size is one of the parameters to characterize the performance of a radiographic X-ray source.It determines the degree of blurring due to magnification directly.In recent years,a variety of measurement methods have been used to diagnose X-ray spot size at Laboratory of Accelerator Physics and Application (LAPA).Computer simulations and experiments showed that using a rolled-edge to measure the spot size are more accurate,and the intensity distribution of X-ray source was obtained by a device with a square aperture.Experimental and simulation results on a flash X-ray source at our laboratory are presented and discussed in this paper.In addition,a new method for time resolved diagnostics of X-ray spot size is introduced too.

  2. The Chandra Survey of Extragalactic Sources in the 3CR Catalog: X-ray Emission from Nuclei, Jets, and Hotspots in the Chandra Archival Observations

    CERN Document Server

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

    2016-01-01

    As part of our program to build a complete radio and X-ray database of all the 3CR extragalactic radio sources, we present an analysis of 93 sources for which Chandra archival data are available. Most of these sources have been already 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 VLA archive. For about 1/3 of the sources in the selected sample a comparison between the Chandra and the 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 of 15 galaxy clusters, two of which were most likely unknown previously.

  3. 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.

  4. X-Ray bright active galactic nuclei in massive galaxy clusters - II. The fraction of galaxies hosting active nuclei

    DEFF Research Database (Denmark)

    Ehlert, S.; von der Linden, A.; Allen, S. W.

    2013-01-01

    We present a measurement of the fraction of cluster galaxies hosting X-ray bright active galactic nuclei (AGN) as a function of clustercentric distance scaled in units of r500. Our analysis employs high-quality Chandra X-ray and Subaru optical imaging for 42 massive X-ray-selected galaxy cluster......, both of which are also suppressed near cluster centres to a comparable extent. These results strongly support the idea that X-ray AGN activity and strong star formation are linked through their common dependence on available reservoirs of cold gas....... fields spanning the redshift range 0.2 cluster galaxy AGN fraction in the central...

  5. Hard X-ray sources from miniature plasma focus devices

    Energy Technology Data Exchange (ETDEWEB)

    Raspa, V. [Buenos Aires Univ., PLADEMA, CONICET and INFIP (Argentina); Silva, P.; Moreno, J.; Zambra, M.; Soto, L. [Comision Chilena de Energia Nuclear, Santiago (Chile)

    2004-07-01

    As first stage of a program to design a repetitive pulsed radiation generator for industrial applications, two miniature plasma foci have been designed and constructed at the Chilean commission of nuclear energy. The devices operate at an energy level of the order of tens of joules (PF-50 J, 160 nF capacitor bank, 20-35 kV, 32-100 J, {approx} 150 ns time to peak current) and hundred of joules (PF-400 J, 880 nF, 20-35 kV, 176-539 J, {approx} 300 ns time to peak current). Hard X-rays are being studied in these devices operating with hydrogen. Images of metallic plates with different thickness were obtained on commercial radiographic film, Agfa Curix ST-G2, in order to characterize the energy of the hard X-ray outside of the discharge chamber of PF-400 J. An effective energy of the order of 90 keV was measured under those conditions. X ray images of different metallic objects also have been obtained. (authors)

  6. Small-animal tomography with a liquid-metal-jet x-ray source

    Science.gov (United States)

    Larsson, D. H.; Lundström, U.; Westermark, U.; Takman, P. A. C.; Burvall, A.; Arsenian Henriksson, M.; Hertz, H. M.

    2012-03-01

    X-ray tomography of small animals is an important tool for medical research. For high-resolution x-ray imaging of few-cm-thick samples such as, e.g., mice, high-brightness x-ray sources with energies in the few-10-keV range are required. In this paper we perform the first small-animal imaging and tomography experiments using liquid-metal-jet-anode x-ray sources. This type of source shows promise to increase the brightness of microfocus x-ray systems, but present sources are typically optimized for an energy of 9 keV. Here we describe the details of a high-brightness 24-keV electron-impact laboratory microfocus x-ray source based on continuous operation of a heated liquid-In/Ga-jet anode. The source normally operates with 40 W of electron-beam power focused onto the metal jet, producing a 7×7 μm2 FWHM x-ray spot. The peak spectral brightness is 4 × 109 photons / ( s × mm2 × mrad2 × 0.1%BW) at the 24.2 keV In Kα line. We use the new In/Ga source and an existing Ga/In/Sn source for high-resolution imaging and tomography of mice.

  7. Magnetic fields, winds and X-rays of massive stars in the Orion Nebula Cluster

    CERN Document Server

    Petit, V; Drissen, L; Montmerle, T; Alecian, E

    2008-01-01

    In massive stars, magnetic fields are thought to confine the outflowing radiatively-driven wind, resulting in X-ray emission that is harder, more variable and more efficient than that produced by instability-generated shocks in non-magnetic winds. Although magnetic confinement of stellar winds has been shown to strongly modify the mass-loss and X-ray characteristics of massive OB stars, we lack a detailed understanding of the complex processes responsible. The aim of this study is to examine the relationship between magnetism, stellar winds and X-ray emission of OB stars. In conjunction with a Chandra survey of the Orion Nebula Cluster, we carried out spectropolarimatric ESPaDOnS observations to determine the magnetic properties of massive OB stars of this cluster.

  8. A search for hyperluminous X-ray sources in the XMM-Newton source catalog

    CERN Document Server

    Zolotukhin, Ivan; Godet, Olivier; Bachetti, Matteo; Barret, Didier

    2015-01-01

    We present a new method to identify luminous off-nuclear X-ray sources in the outskirts of galaxies from large public redshift surveys, distinguishing them from foreground and background interlopers. Using the 3XMM-DR5 catalog of X-ray sources and the SDSS DR12 spectroscopic sample of galaxies, with the help of this off-nuclear cross-matching technique, we selected 98 sources with inferred X-ray luminosities in the range $10^{41} < L_{\\rm X} < 10^{44}\\,{\\rm erg\\,s}^{-1}$, compatible with hyperluminous X-ray objects (HLX). To validate the method, we verify that it allowed us to recover known HLX candidates such as ESO 243$-$49 HLX$-$1 and M82 X$-$1. From a statistical study, we conservatively estimate that up to $71 \\pm 11$ of these sources may be fore- or background sources, statistically leaving at least 16 that are likely to be HLXs, thus providing support for the existence of the HLX population. We identify two good HLX candidates and using other publicly available datasets, in particular the VLA FIR...

  9. Investigating the velocity structure and X-ray observable properties of simulated galaxy clusters with PHOX

    CERN Document Server

    Biffi, Veronica; Boehringer, Hans

    2012-01-01

    Non-thermal motions in the intra-cluster medium (ICM) are believed to play a non-negligible role in the pressure support to the total gravitating mass of galaxy clusters. Future X-ray missions, such as ASTRO-H and ATHENA, will eventually allow us to directly detect the signature of these motions from high-resolution spectra of the ICM. In this paper, we present a study on a set of clusters extracted from a cosmological hydrodynamical simulation, devoted to explore the role of non-thermal velocity amplitude in characterising the cluster state and the relation between observed X-ray properties. In order to reach this goal, we apply the X-ray virtual telescope PHOX to generate synthetic observations of the simulated clusters with both Chandra and ATHENA, the latter used as an example for the performance of very high-resolution X-ray telescopes. From Chandra spectra we extract global properties, e.g. luminosity and temperature, and from ATHENA spectra we estimate the gas velocity dispersion along the line of sigh...

  10. The MUSIC of Galaxy Clusters II: X-ray global properties and scaling relations

    CERN Document Server

    Biffi, Veronica; De Petris, Marco; Valdarnini, Riccardo; Yepes, Gustavo; Gottlöber, Stefan

    2014-01-01

    We present the X-ray properties and scaling relations of a large sample of clusters extracted from the Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC) dataset. We focus on a sub-sample of 179 clusters at redshift z~0.11, with 3.2e14M_sun/hX-ray photon simulator PHOX to obtain synthetic Chandra Observations and derive observable-like global properties of the intracluster medium (ICM), as X-ray temperature (T_X) and luminosity (L_X). T_X is found to slightly under-estimate the true mass-weighted temperature, although tracing fairly well the cluster total mass. We also study the effects of T_X on scaling relations with cluster intrinsic properties: total (M_500) and gas (M_g500) mass; integrated Compton parameter (Y_SZ) of the Sunyaev-Zel'dovich (SZ) thermal effect; Y_X=M_g500 T_X. We confirm that Y_X is a very good mass proxy, with a scatter on M_500-Y_X and Y_SZ-Y_X lower than 5%. The study of scaling relations among X-ray, intrinsic and S...

  11. COnstrain Dark Energy with X-ray (CODEX) clusters

    Science.gov (United States)

    Finoguenov, Alexis; SDSS Team; Cfht Team; Carma Team

    2012-09-01

    We describe the construction and follow-up observations of the most massive clusters in the Universe, selected in the SDSS-III survey using RASS data down to an unprecedented flux limit of -13 dex. In application to the cosmology studies, we demonstrate that we will achieve a 3% constraint on the dark energy equation of state, and in a combination with BOSS BAO measurement reach a FoM of 160.

  12. X-ray properties of the young open clusters HM1 and IC 2944/2948

    Science.gov (United States)

    Nazé, Y.; Rauw, G.; Sana, H.; Corcoran, M. F.

    2013-07-01

    Using XMM-Newton data, we study for the first time the X-ray emission of HM1 and IC 2944/2948. Low-mass, pre-main-sequence objects with an age of a few Myr are detected, as well as a few background or foreground objects. Most massive stars in both clusters display the usual high-energy properties of that type of objects, though with log [LX/LBOL] apparently lower in HM1 than in IC 2944/2948. Compared with studies of other clusters, it seems that a low signal-to-noise ratio at soft energies, due to the high extinction, may be the main cause of this difference. In HM1, the two Wolf-Rayet stars show contrasting behaviors: WR89 is extremely bright, but much softer than WR87. It remains to be seen whether wind-wind collisions or magnetically confined winds can explain these emissions. In IC 2944/2948, the X-ray sources concentrate around HD 101205; a group of massive stars to the north of this object is isolated, suggesting that there exist two subclusters in the field-of-view. Tables 2, 5, and Figs. 5, 9 are available in electronic form at http://www.aanda.orgBased on observations collected with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).Tables 1, 3 and 4 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/555/A83

  13. X-ray Sources in the Hubble Deep Field Detected by Chandra

    CERN Document Server

    Hornschemeier, A E; Garmire, G P; Schneider, D P; Broos, P S; Townsley, L K; Bautz, M W; Burrows, D N; Chartas, G; Feigelson, E D; Griffiths, R; Lumb, D H; Nousek, J A; Sargent, W L W

    2000-01-01

    We present first results from an X-ray study of the Hubble Deep Field North (HDF-N) and its environs obtained using 166 ks of data collected by the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-ray Observatory. This is the deepest X-ray observation ever reported, and in the HDF-N itself we detect six X-ray sources down to a 0.5--8 keV flux limit of 4E-16 erg cm^-2 s^-1. Comparing these sources with objects seen in multiwavelength HDF-N 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. The X-ray emission from the ellipticals is consistent with that expected from a hot interstellar medium, and the spiral galaxy emission may arise from a `super-Eddington' X-ray binary or ultraluminous supernova remnant. Four of the X-ray sources have been detected at radio wavelengths. We also place X-ray upper limits on AGN candidates found in the HDF-N, and we present the t...

  14. THE CHANDRA LOCAL VOLUME SURVEY: THE X-RAY POINT-SOURCE CATALOG OF NGC 300

    Energy Technology Data Exchange (ETDEWEB)

    Binder, B.; Williams, B. F.; Dalcanton, J. J.; Anderson, S. F.; Weisz, D. R. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Eracleous, M. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Gaetz, T. J.; Plucinsky, P. P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street Cambridge, MA 02138 (United States); Skillman, E. D. [Astronomy Department, University of Minnesota, 116 Church St. SE, Minneapolis, MN 55455 (United States); Kong, A. K. H. [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2012-10-10

    We present the source catalog of a new Chandra ACIS-I observation of NGC 300 obtained as part of the Chandra Local Volume Survey. Our 63 ks exposure covers {approx}88% of the D{sub 25} isophote (R Almost-Equal-To 6.3 kpc) and yields a catalog of 95 X-ray point sources detected at high significance to a limiting unabsorbed 0.35-8 keV luminosity of {approx}10{sup 36} erg s{sup -1}. Sources were cross-correlated with a previous XMM-Newton catalog, and we find 75 'X-ray transient candidate' sources that were detected by one observatory, but not the other. We derive an X-ray scale length of 1.7 {+-} 0.2 kpc and a recent star formation rate of 0.12 M{sub Sun} yr{sup -1} in excellent agreement with optical observations. Deep, multi-color imaging from the Hubble Space Telescope, covering {approx}32% of our Chandra field, was used to search for optical counterparts to the X-ray sources, and we have developed a new source classification scheme to determine which sources are likely X-ray binaries, supernova remnants, and background active galactic nucleus candidates. Finally, we present the X-ray luminosity functions (XLFs) at different X-ray energies, and we find the total NGC 300 X-ray point-source population to be consistent with other late-type galaxies hosting young stellar populations ({approx}< 50 Myr). We find that XLF of sources associated with older stellar populations has a steeper slope than the XLF of X-ray sources coinciding with young stellar populations, consistent with theoretical predictions.

  15. An X-ray survey of clusters of galaxies. IV - A survey of southern clusters and a compilation of upper limits for both Abell and southern clusters

    Science.gov (United States)

    Kowalski, M. P.; Ulmer, M. P.; Cruddace, R. G.; Wood, K. S.

    1984-12-01

    The results of the HEAO 1 A-1 X-ray survey of galaxy clusters are reported. X-ray error boxes and intensities are presented for all clusters in the Abell catalog and for the catalog of southern clusters and groups compiled by Duus and Newell (1977). A correlation is derived on the basis of the X-ray luminosity function for 2-6 keV which may be used to calculate the contribution of clusters to the diffuse X-ray background at different energies. The cluster X-ray is estimated to be 9.3 percent (+ 1.9 or - 1.5 percent). Correlations between X-ray luminosity and other cluster properties are exmained, and it is found that the distribution of upper limits may be applied to obtaining a more precise estimate of the average X-ray luminosity of clusters. The Abell richness class and southern cluster concentrations were strongly correlated with X-ray luminosity. Correlations between optical x-ray luminosity and optical radius velocity dispersion, spiral fraction, and radio power are analyzed. The evidence for all these correlations was considered to be weak because of poor scatter in the data.

  16. Infrared identification of hard X-ray sources in the Galaxy

    CERN Document Server

    Gómez-Morán, A Nebot; Pineau, F -X; Carrera, F J; Pakull, M W; Riddick, F

    2015-01-01

    The nature of the low- to intermediate-luminosity (Lx$\\,\\sim 10^{32-34}$ erg s$^{-1}$) source population revealed in hard band (2-10 keV) X-ray surveys of the Galactic Plane is poorly understood. To overcome such problem we cross-correlated the XMM-Newton 3XMM-DR4 survey with the infrared 2MASS and GLIMPSE catalogues. We identified reliable X-ray-infrared associations for 690 sources. We selected 173 sources having hard X-ray spectra, typical of hard X-ray high-mass stars (kT$\\,>\\,5\\,$keV), and 517 sources having soft X-ray spectra, typical of active coronae. About $18\\,\\%$ of the soft sources are classified in the literature: $\\sim\\,91\\%$ as stars, with a minor fraction of WR stars. Roughly $15\\,\\%$ of the hard sources are classified in the literature: $\\sim\\,68\\%$ as high-mass X-ray stars single or in binary systems (WR, Be and HMXBs), with a small fraction of G and B stars. We carried out infrared spectroscopic pilot observations at the William Herschel Telescope for five hard X-ray sources. Three of them ...

  17. OPTICAL STUDY OF THE HYPER-LUMINOUS X-RAY SOURCE 2XMM J011942.7+032421

    Energy Technology Data Exchange (ETDEWEB)

    Gutiérrez, Carlos M. [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Moon, Dae-Sik, E-mail: cgc@iac.es [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada)

    2014-12-10

    We present the identification and characterization of the optical counterpart to 2XMM J011942.7+032421, one of the most luminous and distant ultra-luminous X-ray sources (ULXs). The counterpart is located near a star-forming region in a spiral arm of the galaxy NGC 470 with u, g, and r magnitudes of 21.53, 21.69, and 21.71 mag, respectively. The luminosity of the counterpart is much larger than that of a single O-type star, indicating that it may be a stellar cluster. Our optical spectroscopic observations confirm the association of the X-ray source and the optical counterpart with its host galaxy NGC 470, which validates the high, ≳10{sup 41} erg s{sup -1}, X-ray luminosity of the source. Its optical spectrum is embedded with numerous emission lines, including H recombination lines, metallic forbidden lines, and more notably the high-ionization He II (λ4686) line. That line shows a large velocity dispersion of ≅410 km s{sup -1}, consistent with the existence of a compact (<5 AU) highly ionized accretion disk rotating around the central X-ray source. The ∼1.4 × 10{sup 37} erg s{sup -1} luminosity of the He II line emission makes the source one of the most luminous ULXs in that emission. This, together with the high X-ray luminosity and the large velocity dispersion of the He II emission, suggests that the source is an ideal candidate for more extensive follow-up observations for understanding the nature of hyper-luminous X-ray sources, a more luminous subgroup of ULXs, and more likely candidates for intermediate-mass black holes.

  18. Search for cooling flows in southern X-ray clusters of galaxies

    Science.gov (United States)

    Nesci, R.; Altamore, A.

    1990-08-01

    EFOSC spectroscopic observations of 20 galaxies belonging to 10 distant X-ray southern clusters, selected from the HEAO1-A1 catalogue, are presented. The redshifts derived for the observed clusters (z = 0.15) are systematically lower than expected from their Duus and Newell distance class, but in good agreement with the distance class reported in the southern clusters catalog by Abell, Corwin, and Olowin. In the central cluster galaxies, no emission lines typical of cooling flow clusters, with negative results have been found. The '4000 break' amplitudes also have values typical for normal elliptical galaxies. These findings suggest that the observed clusters are unlikely to have strong ongoing cooling flows.

  19. X-ray bright active galactic nuclei in massive galaxy clusters III: New insights into the triggering mechanisms of cluster AGN

    CERN Document Server

    Ehlert, S; Brandt, W N; Canning, R E A; Luo, B; Mantz, A; Morris, R G; von der Linden, A; Xue, Y Q

    2014-01-01

    We present the results of a new analysis of the X-ray selected Active Galactic Nuclei (AGN) population in the vicinity of 135 of the most massive galaxy clusters in the redshift range of 0.2 < z < 0.9 observed with Chandra. With a sample of more than 11,000 X-ray point sources, we are able to measure, for the first time, evidence for evolution in the cluster AGN population beyond the expected evolution of field AGN. Our analysis shows that overall number density of cluster AGN scales with the cluster mass as $\\sim M_{500}^{-1.2}$. There is no evidence for the overall number density of cluster member X-ray AGN depending on the cluster redshift in a manner different than field AGN, nor there is any evidence that the spatial distribution of cluster AGN (given in units of the cluster overdensity radius r_500) strongly depends on the cluster mass or redshift. The $M^{-1.2 \\pm 0.7}$ scaling relation we measure is consistent with theoretical predictions of the galaxy merger rate in clusters, which is expected ...

  20. A NEW METHOD TO QUANTIFY X-RAY SUBSTRUCTURES IN CLUSTERS OF GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Andrade-Santos, Felipe; Lima Neto, Gastao B.; Lagana, Tatiana F. [Departamento de Astronomia, Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Geofisica e Ciencias Atmosfericas, Rua do Matao 1226, Cidade Universitaria, 05508-090 Sao Paulo, SP (Brazil)

    2012-02-20

    We present a new method to quantify substructures in clusters of galaxies, based on the analysis of the intensity of structures. This analysis is done in a residual image that is the result of the subtraction of a surface brightness model, obtained by fitting a two-dimensional analytical model ({beta}-model or Sersic profile) with elliptical symmetry, from the X-ray image. Our method is applied to 34 clusters observed by the Chandra Space Telescope that are in the redshift range z in [0.02, 0.2] and have a signal-to-noise ratio (S/N) greater than 100. We present the calibration of the method and the relations between the substructure level with physical quantities, such as the mass, X-ray luminosity, temperature, and cluster redshift. We use our method to separate the clusters in two sub-samples of high- and low-substructure levels. We conclude, using Monte Carlo simulations, that the method recuperates very well the true amount of substructure for small angular core radii clusters (with respect to the whole image size) and good S/N observations. We find no evidence of correlation between the substructure level and physical properties of the clusters such as gas temperature, X-ray luminosity, and redshift; however, analysis suggest a trend between the substructure level and cluster mass. The scaling relations for the two sub-samples (high- and low-substructure level clusters) are different (they present an offset, i.e., given a fixed mass or temperature, low-substructure clusters tend to be more X-ray luminous), which is an important result for cosmological tests using the mass-luminosity relation to obtain the cluster mass function, since they rely on the assumption that clusters do not present different scaling relations according to their dynamical state.

  1. THE CHANDRA LOCAL VOLUME SURVEY: THE X-RAY POINT-SOURCE POPULATION OF NGC 404

    Energy Technology Data Exchange (ETDEWEB)

    Binder, B.; Williams, B. F.; Weisz, D. R. [University of Washington, Department of Astronomy, Box 351580, Seattle, WA 98195 (United States); Eracleous, M. [Department of Astronomy and Astrophysics and Center for Gravitational Wave Physics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Gaetz, T. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street Cambridge, MA 02138 (United States); Kong, A. K. H. [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Skillman, E. D. [University of Minnesota, Astronomy Department, 116 Church St. SE, Minneapolis, MN 55455 (United States)

    2013-02-15

    We present a comprehensive X-ray point-source catalog of NGC 404 obtained as part of the Chandra Local Volume Survey. A new 97 ks Chandra ACIS-S observation of NGC 404 was combined with archival observations for a total exposure of {approx}123 ks. Our survey yields 74 highly significant X-ray point sources and is sensitive to a limiting unabsorbed luminosity of {approx}6 Multiplication-Sign 10{sup 35} erg s{sup -1} in the 0.35-8 keV band. To constrain the nature of each X-ray source, cross-correlations with multi-wavelength data were generated. We searched overlapping Hubble Space Telescope observations for optical counterparts to our X-ray detections, but find only two X-ray sources with candidate optical counterparts. We find 21 likely low-mass X-ray binaries (LMXBs), although this number is a lower limit due to the difficulties in separating LMXBs from background active galactic nuclei. The X-ray luminosity functions (XLFs) in both the soft and hard energy bands are presented. The XLFs in the soft band (0.5-2 keV) and the hard band (2-8 keV) have a limiting luminosity at the 90% completeness limit of 10{sup 35} erg s{sup -1} and 10{sup 36} erg s{sup -1}, respectively, significantly lower than previous X-ray studies of NGC 404. We find the XLFs to be consistent with those of other X-ray populations dominated by LMXBs. However, the number of luminous (>10{sup 37} erg s{sup -1}) X-ray sources per unit stellar mass in NGC 404 is lower than is observed for other galaxies. The relative lack of luminous XRBs may be due to a population of LMXBs with main-sequence companions formed during an epoch of elevated star formation {approx}0.5 Gyr ago.

  2. Chandra X-ray Observations of 12 Millisecond Pulsars in the Globular Cluster M28

    CERN Document Server

    Bogdanov, Slavko; Servillat, Mathieu; Heinke, Craig O; Grindlay, Jonathan E; Stairs, Ingrid H; Ransom, Scott M; Freire, Paulo C C; Bégin, Steve; Becker, Werner

    2011-01-01

    We present a Chandra X-ray Observatory investigation of the millisecond pulsars (MSPs) in the globular cluster M28 (NGC 6626). In what is one of the deepest X-ray observations of a globular cluster, we firmly detect seven and possibly detect two of the twelve known M28 pulsars. With the exception of PSRs B1821-24 and J1824-2452H, the detected pulsars have relatively soft spectra, with X-ray luminosities 10^30-31 ergs s^-1 (0.3-8 keV),similar to most "recycled" pulsars in 47 Tucanae and the field of the Galaxy, implying thermal emission from the pulsar magnetic polar caps. We present the most detailed X-ray spectrum to date of the energetic PSR B1821-24. It is well described by a purely non-thermal spectrum with spectral photon index 1.23 and luminosity 1.4x10^33Theta(D/5.5 kpc)^2 ergs s^-1 (0.3-8 keV), where Theta is the fraction of the sky covered by the X-ray emission beam(s). We find no evidence for the previously reported line emission feature around 3.3 keV, most likely as a consequence of improvements i...

  3. X-ray source development for EXAFS measurements on the National Ignition Facility

    Science.gov (United States)

    Coppari, F.; Thorn, D. B.; Kemp, G. E.; Craxton, R. S.; Garcia, E. M.; Ping, Y.; Eggert, J. H.; Schneider, M. B.

    2017-08-01

    Extended X-ray absorption Fine Structure (EXAFS) measurements require a bright, spectrally smooth, and broad-band x-ray source. In a laser facility, such an x-ray source can be generated by a laser-driven capsule implosion. In order to optimize the x-ray emission, different capsule types and laser irradiations have been tested at the National Ignition Facility (NIF). A crystal spectrometer is used to disperse the x-rays and high efficiency image plate detectors are used to measure the absorption spectra in transmission geometry. EXAFS measurements at the K-edge of iron at ambient conditions have been obtained for the first time on the NIF laser, and the requirements for optimization have been established.

  4. X-ray Sources Generated from Gas-Filled Laser-Heated Targets

    Energy Technology Data Exchange (ETDEWEB)

    Back, C A; Grun, J; Decker, C D; Davis, J; Laming, J M; Feldman, U; Suter, L J; Landen, O L; Miller, M; Serduke, F; Wuest, C

    2000-06-06

    The X-ray sources in the 4-7 keV energy regime can be produced by laser-irradiating high-Z gas-filled targets with high-powered lasers. A series of experiments have been performed using underdense targets that are supersonically heated with {approx} 35 W of 0.35 {micro}m laser light. These targets were cylindrical Be enclosures that were filled with 1-2 atms of Xe gas. L-shell x-ray emission is emitted from the plasma and detected by Bragg crystal spectrometers and x-ray diodes. Absolute flux measurements show conversion efficiencies of {approx} 10% in the multi-kilovolt x-ray emission. These sources can be used as bright x-ray backlighters or for material testing.

  5. X-ray source development for EXAFS measurements on the National Ignition Facility.

    Science.gov (United States)

    Coppari, F; Thorn, D B; Kemp, G E; Craxton, R S; Garcia, E M; Ping, Y; Eggert, J H; Schneider, M B

    2017-08-01

    Extended X-ray absorption Fine Structure (EXAFS) measurements require a bright, spectrally smooth, and broad-band x-ray source. In a laser facility, such an x-ray source can be generated by a laser-driven capsule implosion. In order to optimize the x-ray emission, different capsule types and laser irradiations have been tested at the National Ignition Facility (NIF). A crystal spectrometer is used to disperse the x-rays and high efficiency image plate detectors are used to measure the absorption spectra in transmission geometry. EXAFS measurements at the K-edge of iron at ambient conditions have been obtained for the first time on the NIF laser, and the requirements for optimization have been established.

  6. Detecting edges in the X-ray surface brightness of galaxy clusters

    CERN Document Server

    Sanders, J S; Russell, H R; Walker, S A; Blundell, K M

    2016-01-01

    The effects of many physical processes in the intracluster medium of galaxy clusters imprint themselves in X-ray surface brightness images. It is therefore important to choose optimal methods for extracting information from and enhancing the interpretability of such images. We describe in detail a gradient filtering edge detection method that we previously applied to images of the Centaurus cluster of galaxies. The Gaussian gradient filter measures the gradient in the surface brightness distribution on particular spatial scales. We apply this filter on different scales to Chandra X-ray observatory images of two clusters with AGN feedback, the Perseus cluster and M87, and a merging system, A3667. By combining filtered images on different scales using radial filters spectacular images of the edges in a cluster are produced. We describe how to assess the significance of features in filtered images. We find the gradient filtering technique to have significant advantages for detecting many kinds of features compar...

  7. Baryons at the edge of the X-ray-brightest galaxy cluster.

    Science.gov (United States)

    Simionescu, Aurora; Allen, Steven W; Mantz, Adam; Werner, Norbert; Takei, Yoh; Morris, R Glenn; Fabian, Andrew C; Sanders, Jeremy S; Nulsen, Paul E J; George, Matthew R; Taylor, Gregory B

    2011-03-25

    Studies of the diffuse x-ray-emitting gas in galaxy clusters have provided powerful constraints on cosmological parameters and insights into plasma astrophysics. However, measurements of the faint cluster outskirts have become possible only recently. Using data from the Suzaku x-ray telescope, we determined an accurate, spatially resolved census of the gas, metals, and dark matter out to the edge of the Perseus Cluster. Contrary to previous results, our measurements of the cluster baryon fraction are consistent with the expected universal value at half of the virial radius. The apparent baryon fraction exceeds the cosmic mean at larger radii, suggesting a clumpy distribution of the gas, which is important for understanding the ongoing growth of clusters from the surrounding cosmic web.

  8. On the Self-Similar Appearance of Galaxy Clusters in X-rays

    CERN Document Server

    Boehringer, Hans; Chon, Gayoung

    2011-01-01

    The largest uncertainty for cosmological studies using clusters of galaxies is introduced by our limited knowledge of the statistics of galaxy cluster structure, and of the scaling relations between observables and cluster mass. A large effort is therefore undertaken to compile global galaxy cluster properties in particular obtained through X-ray observations and to study their scaling relations. However, the scaling schemes used in the literature differ. The present paper aims to clarify this situation by providing a thorough review of the scaling laws within the standard model of large-scale structure growth and to discus various steps of practical approximations. We derive the scaling laws for X-ray observables and cluster mass within the pure gravitational structure growth scenario. Using N-body simulations we test the recent formation approximation used in earlier analytic approaches which involves a redshift dependent overdensity parameter.We find this approximation less precise than the use of a fiduci...

  9. The XXL Survey. VI. The 1000 brightest X-ray point sources

    Science.gov (United States)

    Fotopoulou, S.; Pacaud, F.; Paltani, S.; Ranalli, P.; Ramos-Ceja, M. E.; Faccioli, L.; Plionis, M.; Adami, C.; Bongiorno, A.; Brusa, M.; Chiappetti, L.; Desai, S.; Elyiv, A.; Lidman, C.; Melnyk, O.; Pierre, M.; Piconcelli, E.; Vignali, C.; Alis, S.; Ardila, F.; Arnouts, S.; Baldry, I.; Bremer, M.; Eckert, D.; Guennou, L.; Horellou, C.; Iovino, A.; Koulouridis, E.; Liske, J.; Maurogordato, S.; Menanteau, F.; Mohr, J. J.; Owers, M.; Poggianti, B.; Pompei, E.; Sadibekova, T.; Stanford, A.; Tuffs, R.; Willis, J.

    2016-06-01

    Context. X-ray extragalactic surveys are ideal laboratories for the study of the evolution and clustering of active galactic nuclei (AGN). Usually, a combination of deep and wide surveys is necessary to create a complete picture of the population. Deep X-ray surveys provide the faint population at high redshift, while wide surveys provide the rare bright sources. Nevertheless, very wide area surveys often lack the ancillary information available for modern deep surveys. The XXL survey spans two fields of a combined 50 deg2 observed for more than 6Ms with XMM-Newton, occupying the parameter space that lies between deep surveys and very wide area surveys; at the same time it benefits from a wealth of ancillary data. Aims: This paper marks the first release of the XXL point source catalogue including four optical photometry bands and redshift estimates. Our sample is selected in the 2 - 10 keV energy band with the goal of providing a sizable sample useful for AGN studies. The limiting flux is F2 - 10 keV = 4.8 × 10-14 erg s-1 cm-2. Methods: We use both public and proprietary data sets to identify the counterparts of the X-ray point-like sources by means of a likelihood ratio test. We improve upon the photometric redshift determination for AGN by applying a Random Forest classification trained to identify for each object the optimal photometric redshift category (passive, star forming, starburst, AGN, quasi-stellar objects (QSO)). Additionally, we assign a probability to each source that indicates whether it might be a star or an outlier. We apply Bayesian analysis to model the X-ray spectra assuming a power-law model with the presence of an absorbing medium. Results: We find that the average unabsorbed photon index is ⟨Γ⟩ = 1.85 ± 0.40 while the average hydrogen column density is log ⟨NH⟩ = 21.07 ± 1.2 cm-2. We find no trend of Γ or NH with redshift and a fraction of 26% absorbed sources (log NH> 22) consistent with the literature on bright sources (log

  10. X-ray structures in galaxy cluster cores

    CERN Document Server

    Pierre, M; Pierre, Marguerite; Starck, Jean-Luc

    1997-01-01

    Using a set of ROSAT HRI deep pointings, we investigate the presence of small-scale structures in the central regions of clusters of galaxies. Our sample comprises 23 objects up to z=0.32, 13 of them known to host a cooling flow. Structures are detected and characterized using a wavelet analysis, their statistical significance being assessed by a rigorous treatment of photon noise. We then investigate in detail the geometrical properties of the smallest scale structures. Contrary to previous claims, we find very few ``filaments'' or point-like features at a 3.7 sigma level, except at the very cluster centers. Complex cores are conspicuous in at least three massive cooling flows located at z = 0.22-0.26. From our initial data set we have simulated a redshifted sample, and analyzed it in the same way in order to investigate any instrumental/resolution effect on the detectability of structures. On the one hand, the topology of the core down to the limiting resolution appears to be, at least in our redshift range...

  11. The Evolution of X-Ray Clusters in a Low-Density Universe

    Science.gov (United States)

    Eke, Vincent R.; Navarro, Julio F.; Frenk, Carlos S.

    1998-08-01

    We present results of N-body/gasdynamical simulations designed to investigate the evolution of X-ray clusters in a flat, low-density, Λ-dominated cold dark matter (CDM) cosmogony. The simulations include self-gravity, pressure gradients, and hydrodynamical shocks, but neglect radiative cooling. The density profile of the dark matter component can be fitted accurately by the simple formula originally proposed by Navarro, Frenk, & White to describe the structure of clusters in a CDM universe with Ω = 1. In projection, the shape of the dark matter radial density profile and the corresponding line-of-sight velocity dispersion profile are in very good agreement with the observed profiles for galaxies in the Canadian Network for Observational Cosmology sample of clusters. This suggests that galaxies are not strongly segregated relative to the dark matter in X-ray luminous clusters. The gas in our simulated clusters is less centrally concentrated than the dark matter, and its radial density profile is well described by the familiar β-model. As a result, the average baryon fraction within the virial radius (rvir) is only 85%-90% of the universal value and is lower nearer the center. The total mass and velocity dispersion of our clusters can be accurately inferred (with ~15% uncertainty) from their X-ray emission-weighted temperature. We generalize Kaiser's scale-free scaling relations to arbitrary power spectra and low-density universes and show that simulated clusters generally follow these relations. The agreement between the simulations and the analytical results provides a convincing demonstration of the soundness of our gasdynamical numerical techniques. Although our simulated clusters resemble observed clusters in several respects, the slope of the luminosity-temperature relation implied by the scaling relations, and obeyed by the simulations, is in disagreement with observations. This suggests that nongravitational effects such as preheating or cooling must have

  12. Burst-only sources: probing type I X-ray bursters at low persistent luminosities

    Energy Technology Data Exchange (ETDEWEB)

    Cornelisse, R.; Zand, J.J.M. in ' t; Kuulkers, E.; Heise, J.; Verbunt, F.; Cocchi, M.; Bazzano, A.; Natalucci, L.; Ubertini, P

    2004-06-01

    The Wide Field Cameras onboard BeppoSAX observed 9 type I X-ray bursters without detectable persistent emission around the burst. According to the standard theory of X-ray bursts these sources should be in the lowest mass-accretion regime, opening the possibility to study this regime for the first time. We compare the sources with the burst theory, and show that the evidence of a new sub-class of low mass X-ray binaries, the burst-only source, is still meagre.

  13. Anti-correlated hard X-ray time lags in Galactic black hole sources

    CERN Document Server

    Sriram, K; Pendharkar, J K; Rao, A R; Pendharkar, Jayant K.

    2007-01-01

    We investigate the accretion disk geometry in Galactic black hole sources by measuring the time delay between soft and hard X-ray emissions. Similar to the recent discoveries of anti-correlated hard X-ray time lags in Cyg X-3 and GRS 1915+105, we find that the hard X-rays are anti-correlated with soft X-rays with a significant lag in another source: XTE J1550-564. We also find the existence of pivoting in the model independent X-ray spectrum during these observations. We investigate time-resolved X-ray spectral parameters and find that the variation in these parameters is consistent with the idea of a truncated accretion disk. The QPO frequency, which is a measure of the size of truncated accretion disk, too changes indicating that the geometric size of the hard X-ray emitting region changes along with the spectral pivoting and soft X-ray flux. Similar kind of delay is also noticed in 4U 1630-47.

  14. X-ray phase-contrast tomography with a compact laser-driven synchrotron source.

    Science.gov (United States)

    Eggl, Elena; Schleede, Simone; Bech, Martin; Achterhold, Klaus; Loewen, Roderick; Ruth, Ronald D; Pfeiffer, Franz

    2015-05-05

    Between X-ray tubes and large-scale synchrotron sources, a large gap in performance exists with respect to the monochromaticity and brilliance of the X-ray beam. However, due to their size and cost, large-scale synchrotrons are not available for more routine applications in small and medium-sized academic or industrial laboratories. This gap could be closed by laser-driven compact synchrotron light sources (CLS), which use an infrared (IR) laser cavity in combination with a small electron storage ring. Hard X-rays are produced through the process of inverse Compton scattering upon the intersection of the electron bunch with the focused laser beam. The produced X-ray beam is intrinsically monochromatic and highly collimated. This makes a CLS well-suited for applications of more advanced--and more challenging--X-ray imaging approaches, such as X-ray multimodal tomography. Here we present, to our knowledge, the first results of a first successful demonstration experiment in which a monochromatic X-ray beam from a CLS was used for multimodal, i.e., phase-, dark-field, and attenuation-contrast, X-ray tomography. We show results from a fluid phantom with different liquids and a biomedical application example in the form of a multimodal CT scan of a small animal (mouse, ex vivo). The results highlight particularly that quantitative multimodal CT has become feasible with laser-driven CLS, and that the results outperform more conventional approaches.

  15. The outer regions of galaxy clusters: Chandra constraints on the X-ray surface brightness

    CERN Document Server

    Ettori, S

    2008-01-01

    (Abridged version) We study the properties of the X-ray surface brightness profiles in a sample of galaxy clusters that are observed with Chandra and have emission detectable with a signal-to-noise ratio larger than 2 at a radius beyond R500 ~ 0.7 R200. Our study aims at measuring the slopes of the X-ray surface brightness and of the gas density profiles in the outskirts of massive clusters. These constraints are then compared to similar results obtained from observations and numerical simulations of the temperature and dark matter density profiles with the intention to present a consistent picture of the outer regions of galaxy clusters. We extract the surface brightness profiles S_b(r) from X-ray exposures obtained with Chandra of 52 X-ray luminous galaxy clusters at z>0.3. We estimate R200 both using a beta-model to reproduce the surface brightness profile and scaling relations from the literature, showing that the two methods converge to comparable values. We evaluate then the radius, R_S2N, at which the ...

  16. X-RAY EMITTING FILAMENTS IN THE COOLING FLOW CLUSTER-A2029

    NARCIS (Netherlands)

    SARAZIN, CL; OCONNELL, RW; MCNAMARA, BR

    1992-01-01

    We present high-resolution X-ray observations of the cluster A2029 with the ROSAT HRI which confirm the presence of a cooling flow, despite the lack of optical line emission or evidence for recent star formation. The cooling rate and radius are M(c) almost-equal-to 370 M. yr-1 and r(c) almost-equal-

  17. X-RAY EMITTING FILAMENTS IN THE COOLING FLOW CLUSTER-A2029

    NARCIS (Netherlands)

    SARAZIN, CL; OCONNELL, RW; MCNAMARA, BR

    1992-01-01

    We present high-resolution X-ray observations of the cluster A2029 with the ROSAT HRI which confirm the presence of a cooling flow, despite the lack of optical line emission or evidence for recent star formation. The cooling rate and radius are M(c) almost-equal-to 370 M. yr-1 and r(c) almost-equal-

  18. A First Estimate Of The X-Ray Binary Frequency As A Function Of Star Cluster Mass In A Single Galactic System

    CERN Document Server

    Clark, D M; Brandl, B R; Wilson, J C; Carson, J C; Henderson, C P; Hayward, T L; Barry, D J; Ptak, A F; Colbert, E J M

    2008-01-01

    We use the previously-identified 15 infrared star-cluster counterparts to X-ray point sources in the interacting galaxies NGC 4038/4039 (the Antennae) to study the relationship between total cluster mass and X-ray binary number. This significant population of X-Ray/IR associations allows us to perform, for the first time, a statistical study of X-ray point sources and their environments. We define a quantity, \\eta, relating the fraction of X-ray sources per unit mass as a function of cluster mass in the Antennae. We compute cluster mass by fitting spectral evolutionary models to K_s luminosity. Considering that this method depends on cluster age, we use four different age distributions to explore the effects of cluster age on the value of \\eta and find it varies by less than a factor of four. We find a mean value of \\eta for these different distributions of \\eta = 1.7 x 10^-8 M_\\sun^-1 with \\sigma_\\eta = 1.2 x 10^-8 M_\\sun^-1. Performing a \\chi^2 test, we demonstrate \\eta could exhibit a positive slope, but t...

  19. First hard x-ray detection of the non-thermal emission around the arches cluster: Morphology and spectral studies with NuSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Krivonos, Roman A.; Tomsick, John A.; Barriere, Nicolas M.; Bodaghee, Arash; Boggs, Steven E.; Craig, William W. [Space Science Lab, University of California, Berkeley, CA 94720 (United States); Bauer, Franz E. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Catlica de Chile, Casilla 306, Santiago 22 (Chile); Baganoff, Frederick K. [MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Christensen, Finn E. [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Grefenstette, Brian W.; Harrison, Fiona A.; Madsen, Kristin K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Hailey, Charles J.; Mori, Kaya; Nynka, Melania [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Hong, JaeSub [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Zhang, William W., E-mail: krivonos@ssl.berkeley.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-02-01

    The Arches cluster is a young, densely packed massive star cluster in our Galaxy that shows a high level of star formation activity. The nature of the extended non-thermal X-ray emission around the cluster remains unclear. The observed bright Fe Kα line emission at 6.4 keV from material that is neutral or in a low ionization state can be produced either by X-ray photoionization or by cosmic-ray particle bombardment or both. In this paper, we report on the first detection of the extended emission around the Arches cluster above 10 keV with the NuSTAR mission, and present results on its morphology and spectrum. The spatial distribution of the hard X-ray emission is found to be consistent with the broad region around the cluster where the 6.4 keV line is observed. The interpretation of the hard X-ray emission within the context of the X-ray reflection model puts a strong constraint on the luminosity of the possible illuminating hard X-ray source. The properties of the observed emission are also in broad agreement with the low-energy cosmic-ray proton excitation scenarioþ.

  20. First hard X-ray detection of the non-thermal emission around the Arches cluster: morphology and spectral studies with NuSTAR

    CERN Document Server

    Krivonos, Roman A; Bauer, Franz E; Baganoff, Frederick K; Barriere, Nicolas M; Bodaghee, Arash; Boggs, Steven E; Christensen, Finn E; Craig, William W; Grefenstette, Brian W; Hailey, Charles J; Harrison, Fiona A; Hong, JaeSub; Madsen, Kristin K; Mori, Kaya; Nynka, Melania; Stern, Daniel; Zhang, William W

    2013-01-01

    The Arches cluster is a young, densely packed massive star cluster in our Galaxy that shows a high level of star formation activity. The nature of the extended non-thermal X-ray emission around the cluster remains unclear. The observed bright Fe K_alpha line emission at 6.4 keV from material that is neutral or in a low ionization state can be produced either by X-ray photoionization or by cosmic-ray particle bombardment or both. In this paper we report on the first detection of the extended emission around the Arches cluster above 10 keV with the NuSTAR mission, and present results on its morphology and spectrum. The spatial distribution of the hard X-ray emission is found to be consistent with the broad region around the cluster where the 6.4 keV line is observed. The interpretation of the hard X-ray emission within the context of the X-ray reflection model puts a strong constraint on the luminosity of the possible illuminating hard X-ray source. The properties of the observed emission are also in broad agre...

  1. Period Clustering of the Anomalous X-Ray Pulsars and Magnetic Field Decay in Magnetars.

    Science.gov (United States)

    Colpi; Geppert; Page

    2000-01-20

    We confront theoretical models for the rotational, magnetic, and thermal evolution of an ultramagnetized neutron star, or magnetar, with available data on the anomalous X-ray pulsars (AXPs). We argue that, if the AXPs are interpreted as magnetars, their clustering of spin periods between 6 and 12 s (observed at present in this class of objects), their period derivatives, their thermal X-ray luminosities, and the association of two of them with young supernova remnants can only be understood globally if the magnetic field in magnetars decays significantly on a timescale of the order of 104 yr.

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

    Science.gov (United States)

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

    2014-03-01

    We present the X-ray properties and scaling relations of a large sample of clusters extracted from the Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC) data set. We focus on a sub-sample of 179 clusters at redshift z ˜ 0.11, with 3.2 × 1014 h-1 M⊙ MUSIC clusters reasonably resemble the self-similar prediction, especially for correlations involving TX. The observational approach also allows for a more direct comparison with real clusters, from which we find deviations mainly due to the physical description of the ICM, affecting TX and, particularly, LX.

  3. From ultraluminous X-ray sources to ultraluminous supersoft sources: NGC 55 ULX, the missing link

    Science.gov (United States)

    Pinto, C.; Alston, W.; Soria, R.; Middleton, M. J.; Walton, D. J.; Sutton, A. D.; Fabian, A. C.; Earnshaw, H.; Urquhart, R.; Kara, E.; Roberts, T. P.

    2017-07-01

    In recent work with high-resolution reflection grating spectrometers (RGS) aboard XMM-Newton, Pinto et al. have discovered that two bright and archetypal ultraluminous X-ray sources (ULXs) have strong relativistic winds in agreement with theoretical predictions of high accretion rates. It has been proposed that such winds can become optically thick enough to block and reprocess the disc X-ray photons almost entirely, making the source appear as a soft thermal emitter or ultraluminous supersoft X-ray source (ULS). To test this hypothesis, we have studied a ULX where the wind is strong enough to cause significant absorption of the hard X-ray continuum: NGC 55 ULX. The RGS spectrum of NGC 55 ULX shows a wealth of emission and absorption lines blueshifted by significant fractions of the light speed (0.01-0.20)c indicating the presence of a powerful wind. The wind has a complex dynamical structure with the ionization state increasing with the outflow velocity, which may indicate launching from different regions of the accretion disc. The comparison with other ULXs such as NGC 1313 X-1 and NGC 5408 X-1 suggests that NGC 55 ULX is being observed at higher inclination. The wind partly absorbs the source flux above 1 keV, generating a spectral drop similar to that observed in ULSs. The softening of the spectrum at lower (˜ Eddington) luminosities and the detection of a soft lag agree with the scenario of wind clumps crossing the line of sight, partly absorbing and reprocessing the hard X-rays from the innermost region.

  4. The X-ray spectral evolution of the ultraluminous X-ray source Holmberg IX X-1

    Science.gov (United States)

    Luangtip, Wasutep; Roberts, Timothy P.; Done, Chris

    2016-08-01

    We present a new analysis of X-ray spectra of the archetypal ultraluminous X-ray source (ULX) Holmberg IX X-1 obtained by the Swift, XMM-Newton and NuSTAR observatories. This ULX is a persistent source, with a typical luminosity of ˜1040 erg s-1, that varied by a factor of 4-5 over eight years. We find that its spectra tend to evolve from relatively flat or two-component spectra in the medium energy band (1-6 keV), at lower luminosities, to a spectrum that is distinctly curved and disc-like at the highest luminosities, with the peak energy in the curved spectrum tending to decrease with increased luminosity. We argue that the spectral evolution of the ULX can be explained by super-Eddington accretion models, where in this case we view the ULX down the evacuated funnel along its rotation axis, bounded by its massive radiatively driven wind. The spectral changes then originate in enhanced geometric beaming as the accretion rate increases and wind funnel narrows, causing the scattered flux from the central regions of the supercritical flow to brighten faster than the isotropic thermal emission from the wind, and so the curved hard spectral component to dominate at the highest luminosities. The wind also Compton down-scatters photons at the edge of the funnel, resulting in the peak energy of the spectrum decreasing. We also confirm that Holmberg IX X-1 displays spectral degeneracy with luminosity, and suggest that the observed differences are naturally explained by precession of the black hole rotation axis for the suggested wind geometry.

  5. Low Energy Plasma Focus as an Intense X-ray Source for Radiography

    Institute of Scientific and Technical Information of China (English)

    S. Hussain; M. Zakaullah; Shujaat Ali; A. Waheed

    2004-01-01

    Study on X-ray emission from a low energy (1.8 k J) plasma focus device powered by a 9 μF capacitor bank, charged at 20 kV and giving peak discharge current of about 175 kA by using a lead-inserted copper-tapered anode is reported. The X-ray yield in different energy windows is measured as a function of hydrogen filling pressure. The maximum yield in 4π-geometry is found to be (27.3±1.1) J and corresponding wall plug efficiency for X-ray generation is 1.52 ±0.06%. X-ray emission, presumably due to bombarding activity of electrons in current sheath at the anode tip was dominant, which is confirmed by the pinhole images. The feasibility of the device as an intense X-ray source for radiography is demonstrated.

  6. The Chandra Local Volume Survey: The X-ray Point Source Population of NGC 404

    CERN Document Server

    Binder, B; Eracleous, M; Gaetz, T J; Kong, A K H; Skillman, E D; Weisz, D R

    2012-01-01

    We present a comprehensive X-ray point source catalog of NGC 404 obtained as part of the Chandra Local Volume Survey. A new, 97 ks Chandra ACIS-S observation of NGC 404 was combined with archival observations for a total exposure of ~123 ks. Our survey yields 74 highly significant X-ray point sources and is sensitive to a limiting unabsorbed luminosity of ~6x10^35 erg s^-1 in the 0.35-8 keV band. To constrain the nature of each X-ray source, cross-correlations with multi-wavelength data were generated. We searched overlapping HST observations for optical counterparts to our X-ray detections, but find only two X-ray sources with candidate optical counterparts. We find 21 likely low mass X-ray binaries (LMXBs), although this number is a lower limit due to the difficulties in separating LMXBs from background AGN. The X-ray luminosity functions (XLFs) in both the soft and hard energy bands are presented. The XLFs in the soft band (0.5-2 keV) and the hard band (2-8 keV) have a limiting luminosity at the 90% comple...

  7. The REX survey a search for Radio Emitting X-ray sources

    CERN Document Server

    Caccianiga, A; Wolter, A; Ceca, R D; Gioia, I M

    1999-01-01

    We present the scientific goals, the strategy and the first results of the REX project, an effort aimed at creating a sizable and statistically complete sample of Radio Emitting X-ray sources (REX) using the available data from a VLA survey and the ROSAT PSPC archive. Through a positional cross-correlation of the two data sets we have derived a sample of about 1600 REX. Among the 393 REX identified so far a high fraction is represented by AGNs, typically radio loud QSOs and BL Lacs. The remaining sources are galaxies, typically radio galaxies isolated or in cluster. Thanks to the low flux limits in the radio and in the X-ray band and the large area of sky covered by the survey, we intend to derive a new complete and unbiased sample of BL Lacs which will contain both ``RBL'' and ``XBL'' type objects. In this way, the apparent dichotomy resulting from the current samples of BL Lacs will be directly analyzed in a unique sample. Moreover, the high number of BL Lacs expected in the REX sample (about 200) will allo...

  8. A deep x-ray survey of the Pleiades cluster and the B6-A3 main sequence stars in Orion

    Science.gov (United States)

    Caillault, Jean-Pierre

    1993-01-01

    We have obtained deep ROSAT images of three regions within the Pleiades open cluster. We have detected 317 X-ray sources in these ROSAT PSPC images, 171 of which we associate with certain probable members of the Pleiades cluster. We detect nearly all Pleiades members with spectral types later than G0 and within 25 arcminutes of our three field centers where our sensitivity is highest. This has allowed us to derive for the first time the luminosity function for the G, K, and M dwarfs of an open cluster without the need to use statistical techniques to account for the presence of upper limits in the data sample. Because of our high X-ray detection frequency down to the faint limit of the optical catalog, we suspect that some of our unidentified X-ray sources are previously unknown, very low-mass members of the Pleiades. A large fraction of the Pleiades members detected with ROSAT have published rotational velocities. Plots of L(sub x)/L(sub bol) versus spectroscopic rotational velocity show tightly correlated 'saturation' type relations for stars with (B - V)(sub O) greater than 0.60. For each of several color ranges, X-ray luminosities rise rapidly with increasing rotation rate until v sin i approximately equals 15 km/s, and then remain essentially flat for rotation rates up to at least v sin i approximately equal to 100 km/s. The dispersion in rotation among low-mass stars in the Pleiades is by far the dominant contributor to the dispersion in L(subx) at a given mass. Only about 35 percent of the B.A. and early F stars in the Pleiades are detected as X-ray sources in our survey. There is no correlation between X-ray flux and rotation for these stars. The X-ray luminosity function for the early-type Pleiades stars appears to be bimodal, with only a few exceptions. We either detect these stars at fluxes in the range found for low-mass stars or we derive X-ray limits below the level found for most Pleiades dwarfs. The X-ray spectra for the early-type Pleiades stars

  9. An X-ray Galaxy Cluster Survey for Investigations of Dark Energy

    CERN Document Server

    Haiman, Z; Bahcall, Neta A; Bautz, M; Böhringer, H; Borgani, S; Bryan, G; Cabrera, B; Canizares, C; Citterio, O; Evrard, A; Finoguenov, A; Griffiths, R; Hasinger, G; Henry, P; Jahoda, K; Jernigan, G; Kahn, S; Lamb, D; Majumdar, S; Mohr, J; Molendi, S; Mushotzky, R; Pareschi, G; Peterson, J; Petre, R; Predehl, P; Rasmussen, A; Ricker, G; Ricker, P; Rosati, P; Sanderson, A; Stanford, A; Voit, Mark; Wang, S; White, N; White, S

    2005-01-01

    The amount and nature of dark energy (DE) can be tightly constrained by measuring the spatial correlation features and evolution of a sample of ~ 100,000 galaxy clusters over the redshift range 0X-ray survey will discover all collapsed structures with mass above 3.5e14 solar masss at redshifts z<2 (i.e. the full range where such objects are expected) in the high Galactic latitude sky. Above this mass threshold the tight correlations between X-ray observables and mass allow direct interpretation of the data. We describe the constraints on Dark Energy that can be inferred from such a survey, using powerful self-calibration techniques to relate the X-ray observables (luminosity and temperature) to the underlying mass.

  10. Catalytic action of β source on x-ray emission from plasma focus

    Science.gov (United States)

    Ahmad, S.; Sadiq, Mehboob; Hussain, S.; Shafiq, M.; Zakaullah, M.; Waheed, A.

    2006-01-01

    The influence of preionization around the insulator sleeve by a mesh-type β source (Ni6328) for the x-ray emission from a (2.3-3.9 kJ) plasma focus device is investigated. Quantrad Si p-i-n diodes along with suitable filters are employed as time-resolved x-ray detectors and a multipinhole camera with absorption filters is used for time-integrated analysis. X-ray emission in 4π geometry is measured as a function of argon and hydrogen gas filling pressures with and without β source at different charging voltages. It is found that the pressure range for the x-ray emission is broadened, x-ray emission is enhanced, and shot to shot reproducibility is improved with the β source. With argon, the CuKα emission is estimated to be 27.14 J with an efficiency of 0.7% for β source and 21.5 J with an efficiency of 0.55% without β source. The maximum x-ray yield in 4π geometry is found to be about 68.90 J with an efficiency of 1.8% for β source and 54.58 J with an efficiency of 1.4% without β source. With hydrogen, CuKα emission is 11.82 J with an efficiency of 0.32% for β source and 10.07 J with an efficiency of 0.27% without β source. The maximum x-ray yield in 4π geometry is found to be 30.20 J with an efficiency of 0.77% for β source and 25.58 J with an efficiency of 0.6% without β source. The x-ray emission with Pb insert at the anode tip without β source is also investigated and found to be reproducible and significantly high. The maximum x-ray yield is estimated to be 46.6 J in 4π geometry with an efficiency of 1.4% at 23 kV charging voltage. However, degradation of x-ray yield is observed when charging voltage exceeds 23 kV for Pb insert. From pinhole images it is observed that the x-ray emission due to the bombardment of electrons at the anode tip is dominant in both with and without β source.

  11. Galaxy cluster X-ray luminosity scaling relations from a representative local sample (REXCESS)

    CERN Document Server

    Pratt, G W; Arnaud, M; Böhringer, H

    2008-01-01

    (Abridged) We examine the X-ray luminosity scaling relations of 31 nearby galaxy clusters from the Representative XMM-Newton Cluster Structure Survey (REXCESS). The objects are selected in X-ray luminosity only, optimally sampling the cluster luminosity function; temperatures range from 2 to 9 keV and there is no bias toward any particular morphological type. Pertinent values are extracted in an aperture corresponding to R_500, estimated using the tight correlation between Y_X and total mass. The data exhibit power law relations between bolometric X-ray luminosity and temperature, Y_X and total mass, all with slopes that are significantly steeper than self-similar expectations. We examine the causes for the steepening, finding that the primary driver appears to be a systematic variation of the gas content with mass. Scatter about the relations is dominated in all cases by the presence of cool cores. The logarithmic scatter about the raw X-ray luminosity-temperature relation is approximately 30%, and that abou...

  12. Omega Dante Soft X-Ray Power Diagnostic Component Calibration at the National Synchrotron Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, K; Weber, F; Dewald, E; Glenzer, S; Landen, O; Turner, R; Waide, P

    2004-04-15

    The Dante soft x-ray spectrometer installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester is a twelve-channel filter-edge defined x-ray power diagnostic. It is used to measure the absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Calibration efforts using two beam lines, U3C (50eV-1keV) and X8A (1keV-6keV) at the National Synchrotron Light Source (NSLS) have been implemented to insure the accuracy of these measurements. We have calibrated vacuum x-ray diodes, mirrors and filters.

  13. Omega Dante soft x-ray power diagnostic component calibration at the National Synchrotron Light Source

    Science.gov (United States)

    Campbell, K. M.; Weber, F. A.; Dewald, E. L.; Glenzer, S. H.; Landen, O. L.; Turner, R. E.; Waide, P. A.

    2004-10-01

    The Dante soft x-ray spectrometer, installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester, is a 12-channel filter-edge defined soft x-ray power diagnostic. It is used to measure the spectrally resolved, absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Dante component calibration efforts using two beam lines, U3C (50 eV-1 keV) and X8A (1-6 keV) at the National Synchrotron Light Source have been implemented to improve the accuracy of these measurements. We have calibrated metallic vacuum x-ray diodes, mirrors and filters.

  14. Phase-contrast imaging of a soft biological object using X-pinch as X-ray source

    Science.gov (United States)

    Liu, R.; Wang, X. X.; Zou, X. B.; Zeng, N. G.; He, L. Y.

    2008-07-01

    The X-ray emission from an X-pinch was measured with diamond photoconducting detectors and a pinhole camera, and the results show that the X-ray source of the X-pinch is extremely small in size and high in brightness. As such, the X-pinch could be considered as an X-ray point source having a high spatial coherence that is required by a simplified scheme of X-ray phase-contrast imaging. The X-pinch was used as X-ray source for the phase-contrast imaging of a weakly X-ray-absorbing mosquito and an image with high contrast was obtained.

  15. A new X-ray transient in the globular cluster Terzan 5

    Science.gov (United States)

    Wijnands, R.; Altamirano, D.; Heinke, C. O.; Sivakoff, G. R.; Pooley, D.

    2012-07-01

    As part of our program (PI: Altamirano) using Swift/XRT to monitor several globular clusters to detect transient behavior of X-ray binaries in those clusters, we obtained a 1.2 ksec observation of Terzan 5 on 6 July 2012. During this observation, we detect a clear excess of photons which was not present during previous Swift observations (i.e., 26 June 2012, 30 June 2012).

  16. A Radio and X-ray Study of the Merging Cluster A2319

    CERN Document Server

    Storm, Emma; Rudnick, Lawrence

    2014-01-01

    A2319 is a massive, merging galaxy cluster with a previously detected radio halo that roughly follows the X-ray emitting gas. We present the results from recent observations of A2319 at 20 cm with the Jansky Very Large Array (VLA) and a re-analysis of the X-ray observations from XMM-Newton, to investigate the interactions between the thermal and nonthermal components of the ICM . We confirm previous reports of an X-ray cold front, and report on the discovery of a distinct core to the radio halo, 800 kpc in extent, that is strikingly similar in morphology to the X-ray emission, and drops sharply in brightness at the cold front. We detect additional radio emission trailing off from the core, which blends smoothly into the 2 Mpc halo detected with the Green Bank Telescope (GBT; Farnsworth et al., 2013). We speculate on the possible mechanisms for such a two-component radio halo, with sloshing playing a dominant role in the core. By directly comparing the X-ray and radio emission, we find that a hadronic origin f...

  17. A new X-ray outburst in the globular cluster NGC 6440 SAX J1748.9-2021

    CERN Document Server

    in 't Zand, J J M; Strohmayer, T E; Bazzano, A; Cocchi, M; Heise, J; Van Kerkwijk, M H; Müller, J M; Natalucci, L; Smith, M J S; Ubertini, P

    1999-01-01

    For the second time in 27 years a bright transient X-ray source has been detected coincident with the globular cluster NGC 6440. It was found to be active in August, 1998, with the Wide Field Camera and the narrow field instruments on the BeppoSAX spacecraft, and with the All-Sky Monitor and the Proportional Counter Array on the RossiXTE spacecraft. Four X-ray bursts were detected, at least one of which shows the characteristics of a thermonuclear flash on a neutron star, in analogy with some ~20 optically identified low-mass X-ray binaries. The broad-band spectrum is hard as is common among low-mass X-ray binaries of lower luminosity (>~10^37 erg/s) and can be explained by a Comptonized model. During the burst the >30 keV emission brightened, consistent with part of the burst emission being Compton up scattered within ~10^11 cm.

  18. A new X-ray outburst in the globular cluster NGC 6440: SAX J1748.9-2021

    Science.gov (United States)

    in 't Zand, J. J. M.; Verbunt, F.; Strohmayer, T. E.; Bazzano, A.; Cocchi, M.; Heise, J.; van Kerkwijk, M. H.; Muller, J. M.; Natalucci, L.; Smith, M. J. S.; Ubertini, P.

    1999-05-01

    For the second time in 27 years a bright transient X-ray source has been detected coincident with the globular cluster NGC 6440. It was found to be active in August, 1998, with the Wide Field Camera and the narrow field instruments on the BeppoSAX spacecraft, and with the All-Sky Monitor and the Proportional Counter Array on the RossiXTE spacecraft. Four X-ray bursts were detected, at least one of which shows the characteristics of a thermonuclear flash on a neutron star, in analogy with some ~ 20 optically identified low-mass X-ray binaries. The broad-band spectrum is hard as is common among low-mass X-ray binaries of lower luminosity (la10 (37) erg s(-1) ) and can be explained by a Comptonized model. During the burst the >30 keV emission brightened, consistent with part of the burst emission being Compton up scattered within ~ 10(11) cm.

  19. Chandra ACIS Survey of X-ray Point Sources: The Source Catalog

    CERN Document Server

    Wang, Song; Qiu, Yanli; Bai, Yu; Yang, Huiqin; Guo, Jincheng; Zhang, Peng

    2016-01-01

    The $Chandra$ archival data is a valuable resource for various studies on different topics of X-ray astronomy. In this paper, we utilize this wealth and present a uniformly processed data set, which can be used to address a wide range of scientific questions. The data analysis procedures are applied to 10,029 ACIS observations, which produces 363,530 source detections, belonging to 217,828 distinct X-ray sources. This number is twice the size of the $Chandra$ Source Catalog (Version 1.1). The catalogs in this paper provide abundant estimates of the detected X-ray source properties, including source positions, counts, colors, fluxes, luminosities, variability statistics, etc. Cross-correlation of these objects with galaxies shows 17,828 sources are located within the $D_{25}$ isophotes of 1110 galaxies, and 7504 sources are located between the $D_{25}$ and 2$D_{25}$ isophotes of 910 galaxies. Contamination analysis with the log$N$--log$S$ relation indicates that 51.3\\% of objects within 2$D_{25}$ isophotes are...

  20. Spectral Clustering for Optical Confirmation and Redshift Estimation of X-ray Selected Galaxy Cluster Candidates in the SDSS Stripe 82

    CERN Document Server

    Mahmoud, Eman; Shoukry, Amin

    2016-01-01

    We develop a galaxy cluster finding algorithm based on spectral clustering technique to identify optical counterparts and estimate optical redshifts for X-ray selected cluster candidates. As an application, we run our algorithm on a sample of X-ray cluster candidates selected from the third XMM-Newton serendipitous source catalog (3XMM-DR5) that are located in the Stripe 82 of the Sloan Digital Sky Survey (SDSS). Our method works on galaxies described in the color-magnitude feature space. We begin by examining 45 galaxy clusters with published spectroscopic redshifts in the range of 0.1 to 0.8 with a median of 0.36. As a result, we are able to identify their optical counterparts and estimate their photometric redshifts, which have a typical accuracy of 0.025 and agree with the published ones. Then, we investigate another 40 X-ray cluster candidates (from the same cluster survey) with no redshift information in the literature and found that 12 candidates are considered as galaxy clusters in the redshift range ...

  1. X-rays beware: the deepest Chandra catalogue of point sources in M31

    Science.gov (United States)

    Vulic, N.; Gallagher, S. C.; Barmby, P.

    2016-10-01

    This study represents the most sensitive Chandra X-ray point source catalogue of M31. Using 133 publicly available Chandra ACIS-I/S observations totalling ˜1 Ms, we detected 795 X-ray sources in the bulge, north-east, and south-west fields of M31, covering an area of ≈0.6 deg2, to a limiting unabsorbed 0.5-8.0 keV luminosity of ˜1034 erg s-1. In the inner bulge, where exposure is approximately constant, X-ray fluxes represent average values because they were determined from many observations over a long period of time. Similarly, our catalogue is more complete in the bulge fields since monitoring allowed more transient sources to be detected. The catalogue was cross-correlated with a previous XMM-Newton catalogue of M31's D25 isophote consisting of 1948 X-ray sources, with only 979 within the field of view of our survey. We found 387 (49 per cent) of our Chandra sources (352 or 44 per cent unique sources) matched to within 5 arcsec of 352 XMM-Newton sources. Combining this result with matching done to previous Chandra X-ray sources we detected 259. new sources in our catalogue. We created X-ray luminosity functions (XLFs) in the soft (0.5-2.0 keV) and hard (2.0-8.0 keV) bands that are the most sensitive for any large galaxy based on our detection limits. Completeness-corrected XLFs show a break around ≈1.3 × 1037 erg s-1, consistent with previous work. As in past surveys, we find that the bulge XLFs are flatter than the disc, indicating a lack of bright high-mass X-ray binaries in the disc and an aging population of low-mass X-ray binaries in the bulge.

  2. A Chandra X-ray study of the young star cluster NGC 6231: low-mass population and initial mass function

    Science.gov (United States)

    Damiani, F.; Micela, G.; Sciortino, S.

    2016-12-01

    Context. NGC 6231 is a massive young star cluster, near the center of the Sco OB1 association. While its OB members are well studied, its low-mass population has received little attention. We present high-spatial resolution Chandra ACIS-I X-ray data, where we detect 1613 point X-ray sources. Aims: Our main aim is to clarify global properties of NGC 6231 down to low masses through a detailed membership assessment, and to study the cluster stars' spatial distribution, the origin of their X-ray emission, the cluster age and formation history, and initial mass function. Methods: We use X-ray data, complemented by optical and IR data, to establish cluster membership. The spatial distribution of different stellar subgroups also provides highly significant constraints on cluster membership, as does the distribution of X-ray hardness. We perform spectral modelling of group-stacked X-ray source spectra. Results: We find a large cluster population down to 0.3 M⊙ (complete to 1 M⊙), with minimal non-member contamination, with a definite age spread (1-8 Myr) for the low-mass PMS stars. We argue that low-mass cluster stars also constitute the majority of the few hundreds unidentified X-ray sources. We find mass segregation for the most massive stars. The fraction of circumstellar-disk bearing members is found to be 5%. Photoevaporation of disks under the action of massive stars is suggested by the spatial distribution of the IR-excess stars. We also find strong Hα emission in 9% of cluster PMS stars. The dependence of X-ray properties on mass, stellar structure, and age agrees with extrapolations based on other young clusters. The cluster initial mass function, computed over 2 dex in mass, has a slope Γ -1.14. The total mass of cluster members above 1 M⊙ is 2.28 × 103M⊙, and the inferred total mass is 4.38 × 103M⊙. We also study the peculiar, hard X-ray spectrum of the Wolf-Rayet star WR 79. Full Tables B.1 and B.2 are only available at the CDS via anonymous ftp

  3. Probing dark energy with the next generation X-ray surveys of galaxy clusters

    CERN Document Server

    Sartoris, B; Rosati, P; Weller, J

    2011-01-01

    We present forecasts on the capability of future wide-area high-sensitivity X-ray surveys of galaxy clusters to yield constraints on the parameters defining the Dark Energy (DE) equation of state (EoS). Our analysis is carried out for future X-ray surveys which have enough sensitivity to provide accurate measurements of X-ray mass proxies and Fe-line based redshifts for about 2x10^4 clusters. We base our analysis on the Fisher Matrix formalism, by combining information on the cluster number counts and power spectrum, also including, for the first time in the analysis of the large scale cluster distribution, the effect of linear redshift-space distortions (RSDs). This study is performed with the main purpose of dissecting the cosmological information provided by geometrical and growth tests, which are both included in the analysis of number counts and clustering of galaxy clusters. We compare cosmological constraints obtained by assuming different levels of prior knowledge of the parameters which define the ob...

  4. An SZ Temperature Decrement X-ray Luminosity Relation for Galaxy Clusters

    CERN Document Server

    Cooray, A R

    1999-01-01

    We present the observed relation between the cosmic microwave background (CMB) temperature decrement due to the Sunyaev-Zeldovich (SZ) effect and the X-ray luminosity of galaxy clusters. We discuss this relation in terms of the cluster properties, and show that the slope of the observed relation is in agreement with both the L-T relation based on numerical simulations and X-ray emission observations, and the M_gas-L relation based on observations. The slope of the Delta T_SZ-L relation is also consistent with the M_tot-L relation, where M_tot is the cluster total mass based on gravitational lensing observations. This agreement may be taken to imply a constant gas mass fraction within galaxy clusters, however, there are large uncertainties, dominated by observational errors, associated with these relations. Using the Delta T_SZ-L relation and the cluster X-ray luminosity function, we evaluate the local cluster contribution to arcminute scale cosmic microwave background anisotropies. The Compton distortion y-pa...

  5. AGN triggering in the infall regions of distant X-ray luminous galaxy clusters at 0.9 < z <~ 1.6

    CERN Document Server

    Fassbender, R; Nastasi, A

    2012-01-01

    Observational constraints on the average radial distribution profile of AGN in distant galaxy clusters can provide important clues on the triggering mechanisms of AGN activity in dense environments and are essential for a completeness evaluation of cluster selection techniques in the X-ray and mm-wavebands. The aim of this work is a statistical study with XMM-Newton of the presence and distribution of X-ray AGN in the large-scale structure environments of 22 X-ray luminous galaxy clusters in the redshift range 0.9 < z \\lesssim 1.6 compiled by the XMM-Newton Distant Cluster Project (XDCP). To this end, the X-ray point source lists from detections in the soft-band (0.35-2.4 keV) and full-band (0.3-7.5 keV) were stacked in cluster-centric coordinates and compared to average background number counts extracted from three independent control fields in the same observations. A significant full-band (soft-band) excess of \\sim78 (67) X-ray point sources is found in the cluster fields within an angular distance of 8...

  6. Long Duration Multi-hohlraum X-ray Sources for Eagle Nebula Laboratory Experiments

    Science.gov (United States)

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

    2013-10-01

    A novel foam-filled multi-hohlraum long-duration x-ray source has been demonstrated at the Omega EP laser and used to obtain L-band spectra of photoionized Ti. A larger scale version of the source will be used in the Science on NIF Eagle Nebula experiments studying dynamic evolution of distinctive pillar and cometary structures in star-forming clouds, where the long duration and directionality of photoionizing radiation from nearby stars generates new classes of flows and instabilities. At NIF, a target representing an astrophysical molecular cloud will be placed several mm from an x-ray source lasting 40-100 ns. At EP, three hohlraums were illuminated in sequence with 3.3 kJ pulses lasting 6 ns, or 4.3 kJ pulses lasting 10 ns, generating 18 or 30 ns of x-ray output at 90-100 eV color temperature. Performance of the source was validated using the μ DMX and VSG spectrometers, ASBO VISAR, and x-ray pinhole imagery. The HYDRA code suggests the EP-scale source can also be shot at NIF with at least 10 kJ per hohlraum. The multi-hohlraum source concept has potential further application to hard x-ray sources, soft x-ray backlighters, and nonlinear ablative hydrodynamics. Prepared by LLNL under Contract DE-AC52-07NA27344. J. Kane supported by DOE OFES grant HEDLP LAB 11-583.

  7. Optical technologies for extreme-ultraviolet and soft X-ray coherent sources

    Energy Technology Data Exchange (ETDEWEB)

    Canova, Federico [Amplitude Technologies, Evry (France); Poletto, Luca (ed.) [National Research Council, Padova (Italy). Inst. of Photonics and Nanotechnology

    2015-07-01

    The book reviews the most recent achievements in optical technologies for XUV and X-ray coherent sources. Particular attention is given to free-electron-laser facilities, but also to other sources available at present, such as synchrotrons, high-order laser harmonics and X-ray lasers. The optical technologies relevant to each type of source are discussed. In addition, the main technologies used for photon handling and conditioning, namely multilayer mirrors, adaptive optics, crystals and gratings are explained. Experiments using coherent light received during the last decades a lot of attention for the X-ray regime. Strong efforts were taken for the realization of almost fully coherent sources, e.g. the free-electron lasers, both as independent sources in the femtosecond and attosecond regimes and as seeding sources for free-electron-lasers and X-ray gas lasers. In parallel to the development of sources, optical technologies for photon handling and conditioning of such coherent and intense X-ray beams advanced. New problems were faced for the realization of optical components of beamlines demanding to manage coherent X-ray photons, e.g. the preservation of coherence and time structure of ultra short pulses.

  8. The Chandra Local Volume Survey: The X-ray Point Source Catalog of NGC 300

    CERN Document Server

    Binder, Breanna; Eracleous, Michael; Gaetz, Terrance J; Plucinsky, Paul P; Skillman, Evan D; Dalcanton, Julianne J; Anderson, Scott F; Weisz, Daniel R; Kong, Albert K H

    2012-01-01

    We present the source catalog of a new Chandra ACIS-I observation of NGC 300 obtained as part of the Chandra Local Volume Survey. Our 63 ks exposure covers ~88% of the D25 isophote (R~6.3 kpc) and yields a catalog of 95 X-ray point sources detected at high significance to a limiting unabsorbed 0.35-8 keV luminosity of ~10^36 erg s^-1. Sources were cross-correlated with a previous XMM-Newton catalog, and we find 75 "X-ray transient candidate" sources that were detected by one observatory, but not the other. We derive an X-ray scale length of 1.7+/-0.2 kpc and a recent star formation rate of 0.12 Msun yr^-1, in excellent agreement with optical observations. Deep, multi-color imaging from the Hubble Space Telescope, covering ~32% of our Chandra field, was used to search for optical counterparts to the X-ray sources, and we have developed a new source classification scheme to determine which sources are likely X-ray binaries, supernova remnants, and background AGN candidates. Finally, we present the X-ray luminos...

  9. Convertible source system of thermal neutron and X-ray at Hokkaido University electron linac facility

    Science.gov (United States)

    Kamiyama, T.; Hara, K. Y.; Taira, H.; Sato, H.

    2016-11-01

    The convertible source system for the neutron and the X-ray imagings was installed in the 45MeV electron linear accelerator facility at Hokkaido University. The source system is very useful for a complementary imaging. The imaging measurements for a sample were performed with both beams by using a vacuum tube type image intensifier. The enhanced contrast was obtained from the dataset of the radiograms measured with the neutron and X-ray beams.

  10. TRANSIENT X-RAY SOURCE POPULATION IN THE MAGELLANIC-TYPE GALAXY NGC 55

    Energy Technology Data Exchange (ETDEWEB)

    Jithesh, V.; Wang, Zhongxiang, E-mail: jithesh@shao.ac.cn [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China)

    2016-04-10

    We present the spectral and temporal properties of 15 candidate transient X-ray sources detected in archival XMM-Newton and Chandra observations of the nearby Magellanic-type, SB(s)m galaxy NGC 55. Based on an X-ray color classification scheme, the majority of the sources may be identified as X-ray binaries (XRBs), and six sources are soft, including a likely supernova remnant. We perform a detailed spectral and variability analysis of the data for two bright candidate XRBs. Both sources displayed strong short-term X-ray variability, and their X-ray spectra and hardness ratios are consistent with those of XRBs. These results, combined with their high X-ray luminosities (∼10{sup 38} erg s{sup −1}), strongly suggest that they are black hole (BH) binaries. Seven less luminous sources have spectral properties consistent with those of neutron star or BH XRBs in both normal and high-rate accretion modes, but one of them is the likely counterpart to a background galaxy (because of positional coincidence). From our spectral analysis, we find that the six soft sources are candidate super soft sources (SSSs) with dominant emission in the soft (0.3–2 keV) X-ray band. Archival Hubble Space Telescope optical images for seven sources are available, and the data suggest that most of them are likely to be high-mass XRBs. Our analysis has revealed the heterogeneous nature of the transient population in NGC 55 (six high-mass XRBs, one low-mass XRBs, six SSSs, one active galactic nucleus), helping establish the similarity of the X-ray properties of this galaxy to those of other Magellanic-type galaxies.

  11. X-Ray surface brightness and gas density fluctuations in the Coma cluster

    CERN Document Server

    Churazov, E; Zhuravleva, I; Schekochihin, A; Parrish, I; Sunyaev, R; Forman, W; Boehringer, H; Randall, S

    2011-01-01

    X-ray surface brightness fluctuations in the core ($650 \\times 650$ kpc) region of the Coma cluster observed with XMM-Newton and Chandra are analyzed using a 2D power spectrum approach. The resulting 2D spectra are converted to 3D power spectra of gas density fluctuations. The characteristic amplitude of the volume filling density fluctuations relative to the smooth underlying density distribution varies from 7-10% on scales of $\\sim$500 kpc down to $\\sim$5% at scales $\\sim$ 30 kpc. On smaller spatial scales, projection effects smear the density fluctuations by a large factor, precluding strong limits on the fluctuations in 3D. On the largest scales probed (hundreds of kpc), the dominant contributions to the observed fluctuations most likely arise from perturbations of the gravitational potential by the two most massive galaxies in Coma, NGC4874 and NGC4889, and the low entropy gas brought to the cluster by an infalling group. Other plausible sources of density fluctuations are discussed, including turbulence...

  12. [Experimental investigation of laser plasma soft X-ray source with gas target].

    Science.gov (United States)

    Ni, Qi-liang; Gong, Yan; Lin, Jing-quan; Chen, Bo; Cao, Jian-lin

    2003-02-01

    This paper describes a debris-free laser plasma soft X-ray source with a gas target, which has high operating frequency and can produce strong soft X-ray radiation. The valve of this light source is drived by a piezoelectrical ceramic whose operating frequency is up to 400 Hz. In comparison with laser plasma soft X-ray sources using metal target, the light source is debris-free. And it has higher operating frequency than gas target soft X-ray sources whose nozzle is controlled by a solenoid valve. A channel electron multiplier (CEM) operating in analog mode is used to detect the soft X-ray generated by the laser plasma source, and the CEM's output is fed to to a charge-sensitive preamplifier for further amplification purpose. Output charges from the CEM are proportional to the amplitude of the preamplifier's output voltage. Spectra of CO2, Xe and Kr at 8-14 nm wavelength which can be used for soft X-ray projection lithography are measured. The spectrum for CO2 consists of separate spectral lines originate mainly from the transitions in Li-like and Be-like ions. The Xe spectrum originating mainly from 4d-5f, 4d-4f, 4d-6p and 4d-5p transitions in multiply charged xenon ions. The spectrum for Kr consists of separate spectral lines and continuous broad spectra originating mainly from the transitions in Cu-, Ni-, Co- and Fe-like ions.

  13. Characterisation and application of a laser-based hard x-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Graetz, M

    1998-11-01

    Hard X-rays are generated by focusing 110 fs laser pulses with intensities of about 1017 W/cm{sup 2} onto solid metal targets. Characteristic properties of this X-ray source are the small source size, the short pulse duration and the high peak flux. The aim of the present work was to characterise this X-ray source and to demonstrate possible applications. A comparison with other X-ray sources and conventional imaging techniques is made. Characterising measurements were performed, including source size, emission spectrum, temporal behaviour, source stability and the influence of various laser parameters. The emission spectrum was measured using both energy-dispersive solid-state detectors and wavelength-dispersive crystal spectroscopy. The conversion efficiency from laser light to X-ray radiation was measured for different target materials. The laser ablation from different targets was studied. The feasibility of special imaging techniques, e.g. differential imaging and time-gated imaging, was investigated both theoretically and experimentally. Differential imaging allows for selective imaging of contrast agents, while time-gated imaging can reduce the influence of scattered radiation in X-ray imaging. Time-gated imaging was demonstrated in different imaging geometries, both for planar imaging and computed tomography imaging. Reasonable agreement between theoretically calculated values and experimental results was obtained 120 refs, figs, tabs

  14. Enhancement of x-ray yields from heteronuclear cluster plasmas irradiated by intense laser light

    Energy Technology Data Exchange (ETDEWEB)

    Jha, J; Mathur, D; Krishnamurthy, M [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India)

    2005-09-28

    We report a new method to enhance the x-ray emission from nano-cluster plasmas formed upon irradiation by intense femtosecond-duration laser pulses. Our experiments demonstrate that when Ar clusters are doped with H{sub 2}O the time-integrated yield of Ar K x-ray emission is enhanced by approximately 12-fold in comparison to that obtained from pure Ar clusters under otherwise identical experimental conditions. A significant alteration in the time-dependent electron density is achieved by the presence of an H{sub 2}O dopant, and this could be the possible reason for the enhancement that is observed. (letter to the editor)

  15. The mass in galaxy clusters from X-ray/SZ observables

    Science.gov (United States)

    Ettori, Stefano

    2016-07-01

    The key tool to use galaxy clusters as astrophysical laboratories and cosmological probes is the knowledge of the distribution of the their gravitating and baryonic mass. I'll discuss the current status in reconstructing the gas and total cluster mass profiles from observations via X-rays and the Sunyeav-Zeldovich effect, highlighting the present limitations and biases, in particular in the clusters' outskirts, I'll show how the use of generalized scaling relations can help to reduce the scatter in obtaining the total mass and to constrain the physics responsible for the observed deviations from the self-similar model. I'll elucidate how Athena, the next-generation X-ray observatory and ESA-L2 mission, will address these issues.

  16. Miniature, low-power X-ray tube using a microchannel electron generator electron source

    Science.gov (United States)

    Elam, Wm. Timothy (Inventor); Kelliher, Warren C. (Inventor); Hershyn, William (Inventor); DeLong, David P. (Inventor)

    2011-01-01

    Embodiments of the invention provide a novel, low-power X-ray tube and X-ray generating system. Embodiments of the invention use a multichannel electron generator as the electron source, thereby increasing reliability and decreasing power consumption of the X-ray tube. Unlike tubes using a conventional filament that must be heated by a current power source, embodiments of the invention require only a voltage power source, use very little current, and have no cooling requirements. The microchannel electron generator comprises one or more microchannel plates (MCPs), Each MCP comprises a honeycomb assembly of a plurality of annular components, which may be stacked to increase electron intensity. The multichannel electron generator used enables directional control of electron flow. In addition, the multichannel electron generator used is more robust than conventional filaments, making the resulting X-ray tube very shock and vibration resistant.

  17. A carbon nanotube field emission multipixel x-ray array source for microradiotherapy application

    Science.gov (United States)

    Wang, Sigen; Calderon, Xiomara; Peng, Rui; Schreiber, Eric C.; Zhou, Otto; Chang, Sha

    2011-05-01

    The authors report a carbon nanotube (CNT) field emission multipixel x-ray array source for microradiotherapy for cancer research. The developed multipixel x-ray array source has 50 individually controllable pixels and it has several distinct advantages over other irradiation source including high-temporal resolution (millisecond level), the ability to electronically shape the form, and intensity distribution of the radiation fields. The x-ray array was generated by a CNT cathode array (5×10) chip with electron field emission. A dose rate on the order of >1.2 Gy/min per x-ray pixel beam is achieved at the center of the irradiated volume. The measured dose rate is in good agreement with the Monte Carlo simulation result.

  18. The ultraluminous X-ray source NGC 1313 X-2 - Its optical counterpart and environment

    CERN Document Server

    Grisé, F; Soria, R; Motch, C; Smith, I A; Ryder, S D; Böttcher, M

    2008-01-01

    NGC 1313 X-2 is one of the brightest ultraluminous X-ray sources in the sky, at both X-ray and optical wavelengths; therefore, quite a few studies of available ESO VLT and HST data have appeared in the literature. Here, we present our analysis of VLT/FORS1 and HST/ACS photometric data, confirming the identification of the B ~ 23 mag blue optical counterpart. We show that the system is part of a poor cluster with an age of 20 Myr, leading to an upper mass limit of some 12 M_sun for the mass donor. We attribute the different results with respect to earlier studies to the use of isochrones in the F435W and F555W HST/ACS photometric system that appear to be incompatible with the corresponding Johnson B and V isochrones. The counterpart exhibits significant photometric variability of about 0.2 mag amplitude, both between the two HST observations and during the one month of monitoring with the VLT. This includes variability within one night and suggests that the light is dominated by the accretion disk in the syste...

  19. Decoding X-ray observations from centres of galaxy clusters using MCMC

    CERN Document Server

    Lakhchaura, Kiran; Sharma, Prateek

    2016-01-01

    Traditionally the thermodynamic profiles (gas density, temperature, etc.) of galaxy clusters are obtained by assuming spherical symmetry and modeling projected X-ray spectra in each annulus. The outer annuli contribute to the inner ones and their contribution needs to be subtracted to obtain the temperature and density of spherical shells. The usual deprojection methods lead to propagation of errors from outside to in and do not model the covariance of parameters in different radial shells. In this paper we describe a method based on a free-form model of clusters with cluster parameters (density, temperature) given in spherical shells, which we {\\it jointly} forward fit to the X-ray data by constructing a Bayesian posterior probability distribution that we sample using the MCMC technique. By systematically marginalising over the nuisance outer shells, we estimate the inner entropy profiles of clusters and fit them to various models for a sample of Chandra X-ray observations of 17 clusters. We show that the en...

  20. Joint deprojection of Sunyaev-Zeldovich and X-ray images of galaxy clusters

    CERN Document Server

    Ameglio, S; Pierpaoli, E; Dolag, K

    2007-01-01

    We present two non-parametric deprojection methods aimed at recovering the three-dimensional density and temperature profiles of galaxy clusters from spatially resolved thermal Sunyaev-Zeldovich (tSZ) and X-ray surface brightness maps, thus avoiding the use of X-ray spectroscopic data. In both methods, clusters are assumed to be spherically symmetric and modeled with an onion-skin structure. The first method follows a direct geometrical approach. The second method is based on the maximization of a single joint (tSZ and X-ray) likelihood function, which allows one to fit simultaneously the two signals by following a Monte Carlo Markov Chain approach. These techniques are tested against a set of cosmological simulations of clusters, with and without instrumental noise. We project each cluster along the three orthogonal directions defined by the principal axes of the momentum of inertia tensor. This enables us to check any bias in the deprojection associated to the cluster elongation along the line of sight. Aft...

  1. A shock front in the merging galaxy cluster Abell 754: X-ray and radio observations

    CERN Document Server

    Macario, Giulia; Giacintucci, Simona; Brunetti, Gianfranco; Venturi, Tiziana; Murray, Stephen S

    2010-01-01

    We present new Chandra X-ray and Giant Meterwave Radio Telescope (GMRT) radio observations of the nearby merging galaxy cluster Abell 754. Our X-ray data confirm the presence of a shock front by obtaining the first direct measurement of a gas temperature jump across the X-ray brightness edge previously seen in the imaging data. A754 is only the fourth galaxy cluster with confirmed merger shock fronts, and it has the weakest shock of those, with a Mach number M=1.57+0.16-0.12. In our new GMRT observation at 330 MHz, we find that the previously-known centrally located radio halo extends eastward to the position of the shock. The X-ray shock front also coincides with the position of a radio relic previously observed at 74 MHz. The radio spectrum of the post-shock region, using our radio data and the earlier results at 74 MHz and 1.4 GHz, is very steep. We argue that acceleration of electrons at the shock front directly from thermal to ultrarelativistic energies is problematic due to energy arguments, while reacc...

  2. The XMM-BCS galaxy cluster survey: I. The X-ray selected cluster catalog from the initial 6 deg$^2$

    CERN Document Server

    Šuhada, R; Böhringer, H; Mohr, J J; Chon, G; Finoguenov, A; Fassbender, R; Desai, S; Armstrong, R; Zenteno, A; Barkhouse, W A; Bertin, E; Buckley-Geer, E J; Hansen, S M; High, F W; Lin, H; Mühlegger, M; Ngeow, C C; Pierini, D; Pratt, G W; Verdugo, M; Tucker, D L

    2011-01-01

    The XMM-Newton - Blanco Cosmology Survey project (XMM-BCS) is a coordinated X-ray, optical and mid-infrared cluster survey in a field also covered by Sunyaev-Zel'dovich effect surveys by the South Pole Telescope and the Atacama Cosmology Telescope. The aim of the project is to study the cluster population in a 14 deg$^2$ field. In this work, we present a catalog of 46 X-ray selected clusters from the initial 6 deg$^2$ survey core. We describe the XMM-BCS source detection pipeline and derive physical properties of the clusters. We provide photometric redshift estimates derived from the BCS imaging data and spectroscopic redshift measurements for a low redshift subset of the clusters. We derive the cluster log N - log S relation using an approximation to the survey selection function and find it in good agreement with previous studies. We carry out an initial comparison between X-ray luminosity derived masses and masses from optical estimators from the Southern Cosmology Survey for a subset of the cluster sampl...

  3. SPIDERS: the spectroscopic follow-up of X-ray selected clusters of galaxies in SDSS-IV

    Science.gov (United States)

    Clerc, N.; Merloni, A.; Zhang, Y.-Y.; Finoguenov, A.; Dwelly, T.; Nandra, K.; Collins, C.; Dawson, K.; Kneib, J.-P.; Rozo, E.; Rykoff, E.; Sadibekova, T.; Brownstein, J.; Lin, Y.-T.; Ridl, J.; Salvato, M.; Schwope, A.; Steinmetz, M.; Seo, H.-J.; Tinker, J.

    2016-09-01

    SPIDERS (The SPectroscopic IDentification of eROSITA Sources) is a program dedicated to the homogeneous and complete spectroscopic follow-up of X-ray AGN and galaxy clusters over a large area (˜7500 deg2) of the extragalactic sky. SPIDERS is part of the SDSS-IV project, together with the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) and the Time-Domain Spectroscopic Survey (TDSS). This paper describes the largest project within SPIDERS before the launch of eROSITA: an optical spectroscopic survey of X-ray selected, massive (˜1014 to 1015~M⊙) galaxy clusters discovered in ROSAT and XMM-Newton imaging. The immediate aim is to determine precise (Δz ˜ 0.001) redshifts for 4,000-5,000 of these systems out to z ˜ 0.6. The scientific goal of the program is precision cosmology, using clusters as probes of large-scale structure in the expanding Universe. We present the cluster samples, target selection algorithms and observation strategies. We demonstrate the efficiency of selecting targets using a combination of SDSS imaging data, a robust red-sequence finder and a dedicated prioritization scheme. We describe a set of algorithms and work-flow developed to collate spectra and assign cluster membership, and to deliver catalogues of spectroscopically confirmed clusters. We discuss the relevance of line-of-sight velocity dispersion estimators for the richer systems. We illustrate our techniques by constructing a catalogue of 230 spectroscopically validated clusters (0.031 < z < 0.658), found in pilot observations. We discuss two potential science applications of the SPIDERS sample: the study of the X-ray luminosity-velocity dispersion (LX - σ) relation and the building of stacked phase-space diagrams.

  4. SPIDERS: the spectroscopic follow-up of X-ray selected clusters of galaxies in SDSS-IV

    Science.gov (United States)

    Clerc, N.; Merloni, A.; Zhang, Y.-Y.; Finoguenov, A.; Dwelly, T.; Nandra, K.; Collins, C.; Dawson, K.; Kneib, J.-P.; Rozo, E.; Rykoff, E.; Sadibekova, T.; Brownstein, J.; Lin, Y.-T.; Ridl, J.; Salvato, M.; Schwope, A.; Steinmetz, M.; Seo, H.-J.; Tinker, J.

    2016-12-01

    SPIDERS (The SPectroscopic IDentification of eROSITA Sources) is a programme dedicated to the homogeneous and complete spectroscopic follow-up of X-ray active galactic nuclei and galaxy clusters over a large area (˜7500 deg2) of the extragalactic sky. SPIDERS is part of the Sloan Digital Sky Survey (SDSS)-IV project, together with the Extended Baryon Oscillation Spectroscopic Survey and the Time-Domain Spectroscopic Survey. This paper describes the largest project within SPIDERS before the launch of eROSITA: an optical spectroscopic survey of X-ray-selected, massive (˜1014-1015 M⊙) galaxy clusters discovered in ROSAT and XMM-Newton imaging. The immediate aim is to determine precise (Δz ˜ 0.001) redshifts for 4000-5000 of these systems out to z ˜ 0.6. The scientific goal of the program is precision cosmology, using clusters as probes of large-scale structure in the expanding Universe. We present the cluster samples, target selection algorithms and observation strategies. We demonstrate the efficiency of selecting targets using a combination of SDSS imaging data, a robust red-sequence finder and a dedicated prioritization scheme. We describe a set of algorithms and work-flow developed to collate spectra and assign cluster membership, and to deliver catalogues of spectroscopically confirmed clusters. We discuss the relevance of line-of-sight velocity dispersion estimators for the richer systems. We illustrate our techniques by constructing a catalogue of 230 spectroscopically validated clusters (0.031 SPIDERS sample: the study of the X-ray luminosity-velocity dispersion (LX-σ) relation and the building of stacked phase-space diagrams.

  5. Electron optics simulation for designing carbon nanotube based field emission x-ray source

    Science.gov (United States)

    Sultana, Shabana

    In this dissertation, electron optics simulation for designing carbon nanotube (CNT) based field emission x-ray source for medical imaging applications will be presented. However, for design optimization of x-ray tubes accurate electron beam optics simulation is essential. To facilitate design of CNT x-ray sources a commercial 3D finite element software has been chosen for extensive simulation. The results show that a simplified model of uniform electron field emission from the cathode surface is not sufficient when compared to experimental measurements. This necessitated the development of a refined model to describe a macroscopic field emission CNT cathode for electron beam optics simulations. The model emulates the random distribution of CNTs and the associated variation of local field enhancement factor. The main parameter of the model has been derived empirically from the experimentally measured I-V characteristics of the CNT cathode. Simulation results based on this model agree well with experiments which include measurements of the transmission rate and focus spot size. The model provides a consistent simulation platform for optimization of electron beam optics in CNT x-ray source design. A systematic study of electron beam optics in CNT x-ray tubes led to the development of a new generation of compact x-ray source with multiple pixels. A micro focus field emission x-ray source with a variable focal spot size has been fully characterized and evaluated. It has been built and successfully integrated into micro-CT scanners which are capable of dynamic cardiac imaging of free-breathing small animals with high spatial and temporal resolutions. In addition a spatially distributed high power multi-beam x-ray source has also been designed and integrated into a stationary digital breast tomosynthesis (s-DBT) configuration. This system has the potential to reduce the total scan time to 4 seconds and yield superior image quality in breast imaging.

  6. 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.

  7. The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Mengning; Williams, Garth J.; Messerschmidt, Marc; Seibert, M. Marvin; Montanez, Paul A.; Hayes, Matt; Milathianaki, Despina; Aquila, Andrew; Hunter, Mark S.; Koglin, Jason E.; Schafer, Donald W.; Guillet, Serge; Busse, Armin; Bergan, Robert; Olson, William; Fox, Kay; Stewart, Nathaniel; Curtis, Robin; Miahnahri, Alireza Alan; Boutet, Sébastien, E-mail: sboutet@slac.stanford.edu [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2015-04-15

    Description of the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source. Recent scientific highlights illustrate the femtosecond crystallography, high power density and extreme matter capabilities of the CXI instrument. The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100 nm focus and one a 1 µm focus, are available, each with multiple diagnostics, sample injection, pump–probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter.

  8. A simulation study of Tsinghua Thomson scattering X-ray source

    Institute of Scientific and Technical Information of China (English)

    TANG Chuan-Xiang; LI Ren-Kai; HUANG Wen-Hui; CHEN Huai-Bi; DU Ying-Chao; DU Qiang; DU Tai-Bin; HE Xiao-Zhong; HUA Jian-Fei; LIN Yu-Zhen; QIAN Hou-Jun; SHI Jia-Ru; XIANG Dao; YAN Li-Xin; Yu Pei-Cheng

    2009-01-01

    Thomson scattering X-ray sources are compact and afrordable facifities that produce short duration,high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies,and also medical and industrial applications.Such a facility has been built at the Accelerator Laboratory of Tsinghua University,and upgrade is in progress.In this paper,we present a proposed layout of the upgrade with design parameters by simulation,aiming at high X-ray pulses flux and brightness,and also enabling advanced dynamics studies and applications of the electron beam.Design and construction status of main subsystems are also presented.

  9. Calibration of a time-resolved hard-x-ray detector using radioactive sources

    Science.gov (United States)

    Stoeckl, C.; Theobald, W.; Regan, S. P.; Romanofsky, M. H.

    2016-11-01

    A four-channel, time-resolved, hard x-ray detector (HXRD) has been operating at the Laboratory for Laser Energetics for more than a decade. The slope temperature of the hot-electron population in direct-drive inertial confinement fusion experiments is inferred by recording the hard x-ray radiation generated in the interaction of the electrons with the target. Measuring the energy deposited by hot electrons requires an absolute calibration of the hard x-ray detector. A novel method to obtain an absolute calibration of the HXRD using single photons from radioactive sources was developed, which uses a thermoelectrically cooled, low-noise, charge-sensitive amplifier.

  10. X-Ray Sources and High-Throughput Data Collection Methods

    Energy Technology Data Exchange (ETDEWEB)

    Snell, Gyorgy

    2012-03-15

    X-ray diffraction experiments on protein crystals are at the core of the structure determination process. An overview of X-ray sources and data collection methods to support structure-based drug design (SBDD) efforts is presented in this chapter. First, methods of generating and manipulating X-rays for the purpose of protein crystallography, as well as the components of the diffraction experiment setup are discussed. SBDD requires the determination of numerous protein-ligand complex structures in a timely manner, and the second part of this chapter describes how to perform diffraction experiments efficiently on a large number of crystals, including crystal screening and data collection.

  11. The Soft X-ray Research instrument at the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Dakovski, Georgi L., E-mail: dakovski@slac.stanford.edu; Heimann, Philip; Holmes, Michael [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Krupin, Oleg [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); European XFEL, Notkestrasse 85, 22607 Hamburg (Germany); Minitti, Michael P.; Mitra, Ankush; Moeller, Stefan; Rowen, Michael; Schlotter, William F.; Turner, Joshua J. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2015-04-02

    A description of the Soft X-ray Research instrument (SXR) at the Linac Coherent Light Source is given. Recent scientific highlights illustrate the wide variety of experiments and detectors that can be accommodated at SXR. The Soft X-ray Research instrument provides intense ultrashort X-ray pulses in the energy range 280–2000 eV. A diverse set of experimental stations may be installed to investigate a broad range of scientific topics such as ultrafast chemistry, highly correlated materials, magnetism, surface science, and matter under extreme conditions. A brief description of the main instrument components will be given, followed by some selected scientific highlights.

  12. Development of a Novel Tunable X-Ray Source for the RPI-LINAC

    Energy Technology Data Exchange (ETDEWEB)

    Y. Danon; R.C. Block

    2004-11-30

    This document summarizes the results of a three year effort to develop a parametric x-ray (PXR) source. The emphasis of this research was to demonstrate production of high yield monoenergetic x-rays. Production of PXR is accomplished by placing a crystal in a relativistic electron beam. The process was first demonstrated in 1985 in Russia. Numerous papers were written about the characteristics of PXR from both experimental and theoretical perspectives. The advantage of PXR over other monoenergetic x-ray sources is that it is produced at large angle relative to the electron beam and at high intensity. None of the previous work described in the literature capitalized on this effect to study what is required in order to generate an effective monoenergetic x-ray source that can be used for practical applications. The work summarized here describes the process done in order to optimize the PXR production process by selecting an appropriate crystal and the optimal conditions. The research focused on production of 18 keV x-rays which are suitable for mammography however the results are not limited to this application or energy range. We are the first group to demonstrate x-ray imaging using PXR. Such sources can improve current medical imaging modalities. More research is required in order to design a prototype of a compact source.

  13. Transient X-ray source population in the Magellanic-type galaxy NGC 55

    CERN Document Server

    Jithesh, V

    2016-01-01

    We present the spectral and temporal properties of 15 candidate transient X-ray sources detected in archival {\\it XMM-Newton} and {\\it Chandra} observations of the nearby Magellanic-type, SB(s)m galaxy NGC 55. On the basis of an X-ray color classification scheme, the majority of the sources may be identified as X-ray binaries (XRBs), and six sources are soft, including a likely supernova remnant. We perform a detailed spectral and variability analysis of the data for two bright candidate XRBs. Both sources displayed strong short-term X-ray variability, and their X-ray spectra and hardness ratios are consistent with those of XRBs. These results, combined with their high X-ray luminosities ($\\sim 10^{38}~\\rm erg~s^{-1}$), strongly suggest that they are black hole (BH) binaries. Seven less luminous sources have spectral properties consistent with those of neutron star or BH XRBs in both normal and high-rate accretion modes, but one of them is the likely counterpart to a background galaxy (because of positional c...

  14. The XMM-BCS galaxy cluster survey: I. The X-ray selected cluster catalog from the initial 6 deg$^2$

    Energy Technology Data Exchange (ETDEWEB)

    Suhada, R.; /Munich, Tech. U. /Munich U.; Song, J.; /Michigan U.; Bohringer, H.; /Munich, Tech. U.; Mohr, J.J.; /Munich, Tech. U. /Munich U. /Munich, Tech. U., Universe; Chon, G.; /Munich, Tech. U.; Finoguenov, A.; /Munich, Tech. U. /CSST, Baltimore; Fassbender, R.; /Munich, Tech. U. /CSST, Baltimore; Desai, S.; /Munich U. /Illinois U., Urbana; Armstrong, R.; /Illinois U., Urbana; Zenteno, A.; /Munich U. /Munich, Tech. U., Universe; Barkhouse, W.A.; /North Dakota U. /Paris, Inst. Astrophys.

    2011-11-01

    The XMM-Newton - Blanco Cosmology Survey project (XMM-BCS) is a coordinated X-ray, optical and mid-infrared cluster survey in a field also covered by Sunyaev-Zel dovich effect (SZE) surveys by the South Pole Telescope and the Atacama Cosmology Telescope. The aim of the project is to study the cluster population in a 14 deg{sup 2} field (center: {alpha} {approx} 23:29:18.4, {delta} {approx} -54:40:33.6). The uniform multi-wavelength coverage will also allow us for the first time to comprehensively compare the selection function of the different cluster detection approaches in a single test field and perform a cross-calibration of cluster scaling relations. In this work, we present a catalog of 46 X-ray selected clusters from the initial 6 deg{sup 2} survey core.We describe the XMM-BCS source detection pipeline and derive physical properties of the clusters. We provide photometric redshift estimates derived from the BCS imaging data and spectroscopic redshift measurements for a low redshift subset of the clusters. The photometric redshift estimates are found to be unbiased and in good agreement with the spectroscopic values. Our multi-wavelength approach gives us a comprehensive look at the cluster and group population up to redshifts z {approx} 1. The median redshift of the sample is 0.47 and the median mass M{sub 500} {approx} 1 x 10{sup 14} M{sub {circle_dot}} ({approx} 2 keV). From the sample, we derive the cluster log N - log S using an approximation to the survey selection function and find it in good agreement with previous studies. We compare optical mass estimates from the Southern Cosmology Survey available for part of our cluster sample with our estimates derived from the X-ray luminosity. Weak lensing masses available for a subset of the cluster sample are in agreement with our estimates. Optical masses based on cluster richness and total optical luminosity are found to be significantly higher than the X-ray values. The present results illustrate the

  15. The effect of AGN feedback on the X-ray morphologies of clusters -- simulations vs. observations

    CERN Document Server

    Chon, Gayoung; Boehringer, Hans

    2016-01-01

    We study the effect of Active Nuclei Galaxy (AGN) feedback as one of the major mechanisms modifying the cluster morphology influencing scaling relations, which are the most uncertain factor in constraining cosmology with clusters of galaxies. Using cosmological hydrodynamical simulations we investigate how the AGN feedback changes the X-ray morphology of the simulated systems, and compare to the observed REXCESS (Representative XMM-Newton Cluster Structure Survey) clusters. We apply centre shifts and power ratios to characterise the cluster morphology, and find that our simulated clusters are more substructured than the observed ones. We show that the degree of this discrepancy is affected by the inclusion of AGN feedback. While the clusters simulated with the AGN feedback are in much better agreement with the REXCESS L_X-T relation, they are also more substructured, which increases the tension with observations. This suggests that not only global cluster properties such as L_X and T and radial profiles shoul...

  16. Chandra Resolves Cosmic X-ray Glow and Finds Mysterious New Sources

    Science.gov (United States)

    2000-01-01

    While taking a giant leap towards solving one of the greatest mysteries of X-ray astronomy, NASA's Chandra X-ray Observatory also may have revealed the most distant objects ever seen in the universe and discovered two puzzling new types of cosmic objects. Not bad for being on the job only five months. Chandra has resolved most of the X-ray background, a pervasive glow of X-rays throughout the universe, first discovered in the early days of space exploration. Before now, scientists have not been able to discern the background's origin, because no X-ray telescope until Chandra has had both the angular resolution and sensitivity to resolve it. "This is a major discovery," said Dr. Alan Bunner, Director of NASA's Structure andEvolution of the universe science theme. "Since it was first observed thirty-seven years ago, understanding the source of the X-ray background has been aHoly Grail of X-ray astronomy. Now, it is within reach." The results of the observation will be discussed today at the 195th national meeting of the American Astronomical Society in Atlanta, Georgia. An article describing this work has been submitted to the journal Nature by Dr. Richard Mushotzky, of NASA Goddard Space Flight Center, Greenbelt, Md., Drs. Lennox Cowie and Amy Barger at the University of Hawaii, Honolulu, and Dr. Keith Arnaud of the University of Maryland, College Park. "We are all very excited by this finding," said Mushotzky. "The resolution of most of the hard X-ray background during the first few months of the Chandra mission is a tribute to the power of this observatory and bodes extremely well for its scientific future," Scientists have known about the X-ray glow, called the X-ray background, since the dawn of X-ray astronomy in the early 1960s. They have been unable to discern its origin, however, for no X-ray telescope until Chandra has had both the angular resolution and sensitivity to resolve it. The German-led ROSAT mission, now completed, resolved much of the lower

  17. Derivation of total filtration thickness for diagnostic x-ray source assembly

    Science.gov (United States)

    Sekimoto, Michiharu; Katoh, Yoh

    2016-08-01

    The method defined by the IEC 60522 for determining the inherent filtration of an x-ray source device is applicable only for a limited range of tube voltage. Because the users cannot legally remove the x-ray movable diaphragm of the x-ray source device, total filtration, which is the sum of the additional filtration diaphragm movable for specific filtration and x-ray, cannot be measured. We develop a method for simply obtaining the total filtration for different tube voltage values. Total filtration can be estimated from a ratio R‧ of the air kerma Kx+T\\prime , which is measured with an Al plate with thickness T, and Kx\\prime measured without an Al plate. The conditions of the target material of the x-ray source device are then entered into the Report 78 Spectrum Processor to calculate the air kerma K x and K x+T for Al thicknesses x and (x  +  T), respectively, to obtain R. The minimum value of x, which is the difference between the R and R‧, is the total filtration of the x-ray source device. The total filtration calculated using the industrial x-ray source device was within  ±1% in the 40-120 kV range. This method can calculate the total filtration using air kerma measurements with and without the Al plate. Therefore, the load on the x-ray tube can be reduced, and preparation of multiple Al plates is not necessary. Furthermore, for the 40-120 kV tube voltage range, the user can easily measure the total filtration.

  18. Optical Identifications of Companion Soft X-ray Sources of Mrk 231

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    We present optical identification results for four ROSAT PSPC soft X-ray companions of Mrk 231 based on the deep BATC 6660 A-band image and the optical spectra obtained by the 60/90cm Schmidt telescope and the 2.16mtelescope at the Xinglong Station, NAOC. Three optical counterparts are quasarswith redshifts z > 1 and the remaining X-ray source is probably a background galaxycluster. Therefore, none of these soft X-ray companions are physically connectedwith the central X-ray source Mrk 231. Incorporating the previous results of Arp 220and Mrk 273 (Xia et al. 1998, 1999), we suggest that the apparent soft X-rayassociations with ULIRGs are chance coincidence in most cases.

  19. Laboratory source based full-field x-ray microscopy at 9 keV

    Energy Technology Data Exchange (ETDEWEB)

    Fella, C.; Balles, A.; Wiest, W. [Lehrstuhl für Röntgenmikroskopie, Julius-Maximilians-Universität, 97074 Würzburg (Germany); Zabler, S.; Hanke, R. [Lehrstuhl für Röntgenmikroskopie, Julius-Maximilians-Universität, 97074 Würzburg (Germany); Fraunhofer Development Center X-Ray Technology (EZRT), Flugplatzstrasse 75, 90768 Fürth (Germany)

    2016-01-28

    In the past decade, hard x-ray transmission microscopy experienced tremendous developments. With the avail-ability of efficient Fresnel zone plates, even set-ups utilizing laboratory sources were developed [1]. In order to improve the performance of these x-ray microscopes, novel approaches to fabricate optical elements [2] and brighter x-ray tubes [3] are promising candidates. We are currently building a laboratory transmission x-ray microscope for 9.25 keV, using an electron impact liquid-metal-jet anode source. Up to now, the further elements of our setup are: a polycapillary condenser, a tungsten zone plate, and a scintillator which is optically coupled to a CMOS camera. However, further variations in terms of optical elements are intended. Here we present the current status of our work, as well as first experimental results.

  20. Fourth-generation X-ray sources: some possible applications to biology.

    Science.gov (United States)

    Doniach, S

    2000-05-01

    The term 'fourth generation X-ray sources' has come to mean X-ray free-electron lasers which use multi-GeV electron beams from linear accelerators to generate X-rays by self-amplified stimulated emission when fired into long undulators. Properties of the radiation expected from such sources are reviewed briefly and two possible applications of the resulting pulsed highly collimated X-radiation to problems in biology are discussed: use of X-ray photon correlation spectroscopy to measure time correlations of atoms in protein crystals, and use of Mössbauer radiation extracted from the photon beams by resonant Bragg diffraction from (57)Fe-containing crystals, for MAD phasing of very large unit-cell biomolecular crystals and possibly for photon echo measurements.

  1. Evidence for Quasi-periodic X-Ray Dips from an Ultraluminous X-Ray Source: Implications for the Binary Motion

    CERN Document Server

    Pasham, Dheeraj R

    2013-01-01

    We report results from long-term (approximately 1240 days) X-ray (0.3-8.0 keV) monitoring of the ultraluminous X-ray source NGC 5408 X-1 with the Swift/X-Ray Telescope. Here we expand on earlier work by Strohmayer (2009) who used only a part of the present data set. Our primary results are: (1) the discovery of sharp, quasi-periodic, energy-independent dips in the X-ray intensity that recur on average every 243 days, (2) the detection of an energy-dependent (variability amplitude decreases with increasing energy), quasi-sinusoidal X-ray modulation with a period of 112.6+-4 days the amplitude of which weakens during the second half of the light curve and (3) spectral evidence for an increase in photoelectric absorption during the last continuous segment of the data. We interpret the X-ray modulations within the context of binary motion in analogy to that seen in high-inclination accreting X-ray binaries. If correct, this implies that NGC 5408 X-1 is in a binary with an orbital period of 243+-23 days, in contra...

  2. The X-ray Binary Population of the Nearby Dwarf Starburst Galaxy IC 10: Variable and Transient X-ray Sources

    CERN Document Server

    Laycock, Silas G T; Williams, Benjamin F; Prestwich, Andrea; Binder, Breanna; Christodoulou, Dimitris M

    2016-01-01

    We have monitored the Cassiopeia dwarf galaxy (IC 10) in a series of 10 Chandra ACIS-S observations to capture its variable and transient X-ray source population, which is expected to be dominated by High Mass X-ray Binaries (HMXBs). We present a sample of 21 X-ray sources that are variable between observations at the 3 sigma level, from a catalog of 110 unique point sources. We find 4 transients (flux variability ratio greater than 10) and a further 8 objects with ratio > 5. The observations span years 2003 - 2010 and reach a limiting luminosity of >10$^{35}$ erg/s, providing sensitivity to X-ray binaries in IC 10 as well as flare stars in the foreground Milky Way. The nature of the variable sources is investigated from light-curves, X-ray spectra, energy quantiles, and optical counterparts. The purpose of this study is to discover the composition of the X-ray binary population in a young starburst environment. IC 10 provides a sharp contrast in stellar population age (<10 My) when compared to the Magella...

  3. Ultraviolet spectroscopy of the supersoft X-ray source RX J0439.8-6809

    Science.gov (United States)

    Van Teeseling, Andre

    1997-07-01

    Observationally, supersoft X-ray sources are classified as near-Eddington stellar objects with almost all emission at energies blue star in the LMC. A 3sigma upper limit to the peak-to-peak optical variability is 0.07 mag. Of all optically identified supersoft X-ray sources, RX J0439.8-6809 has the lowest optical-to-X-ray flux ratio. The nature of RX J0439.8-6809 is still unknown. It might be the hottest known pre-white dwarf, suffering a late helium shell flash. Alternatively, RX J0439.8-6809 could be an accreting binary, in which case it might be the first known double-degenerate supersoft X-ray source with a predicted orbital period of only a few minutes. An ultraviolet spectrum is essential to distinguish between these two spectacular possibilities, and to bridge the gap between the X-ray and optical observations. Such a spectrum can only be obtained with the HST STIS. Therefore, we propose to obtain two ultraviolet spectra, which will test the assumption that the optical spectrum is the Rayleigh-Jeans tail of the soft X-ray component, which will determine the spectral energy distribution, and which may provide the first direct evidence for accretion in this source by detecting an excess in the ultraviolet or ultraviolet emission lines like N V Lambda 1240.

  4. Optical Synchronization Systems for Femtosecond X-raySources

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, Russell; Staples, John W.; Holzwarth, Ronald

    2004-05-09

    In femtosecond pump/probe experiments using short X-Ray and optical pulses, precise synchronization must be maintained between widely separated lasers in a synchrotron or FEL facility. We are developing synchronization systems using optical signals for applications requiring different ranges of timing error over 100 meter of glass fiber. For stabilization in the hundred femtosecond range a CW laser is amplitude modulated at 1 10 GHz, the signal retroreflected from the far end, and the relative phase used to correct the transit time with a piezoelectric phase modulator. For the sub-10 fsec range the laser frequency itself is upshifted 55 MHz with an acousto-optical modulator, retroreflected, upshifted again and phase compared at the sending end to a 110 MHz reference. Initial experiments indicate less than 1 fsec timing jitter. To lock lasers in the sub-10 fs range we will lock two single-frequency lasers separated by several tera Hertz to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes.

  5. Optical Synchronization Systems for Femtosecond X-Ray Sources

    CERN Document Server

    Wilcox, Russell; Staples, John W

    2005-01-01

    In femtosecond pump/probe experiments using short x-ray and optical pulses, precise synchronization must be maintained between widely separated lasers in a synchrotron or FEL facility. We are developing synchronization systems using optical signals for applications requiring different ranges of timing error. For the sub-100fs range we use an amplitude modulated CW laser at 1GHz to transmit RF phase information, and control the delay through a 100m fiber by observing the retroreflected signal. Initial results show 40fs peak-to-peak error above 10Hz, and 200fs long term drift, mainly due to amplitude sensitivity in the analog mixers. For the sub-10fs range we will lock two single-frequency lasers separated by several teraHertz to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes. For attosecond synchronization we propose a stabilized, free space link using bulk lens wavegu...

  6. A scientific case for future X-ray Astronomy: Galaxy Clusters at high redshifts

    CERN Document Server

    Tozzi, Paolo

    2013-01-01

    Clusters of galaxies at high redshift (z>1) are vitally important to understand the evolution of the large scale structure of the Universe, the processes shaping galaxy populations and the cycle of the cosmic baryons, and to constrain cosmological parameters. After 13 years of operation of the Chandra and XMM-Newton satellites, the discovery and characterization of distant X-ray clusters is proceeding at a slow pace, due to the low solid angle covered so far, and the time-expensive observations needed to physically characterize their intracluster medium (ICM). At present, we know that at z>1 many massive clusters are fully virialized, their ICM is already enriched with metals, strong cool cores are already in place, and significant star formation is ongoing in their most massive galaxies, at least at z>1.4. Clearly, the assembly of a large and well characterized sample of high-z X-ray clusters is a major goal for the future. We argue that the only means to achieve this is a survey-optimized X-ray mission capa...

  7. Regulation of the X-ray luminosity of clusters of galaxies by cooling and supernova feedback

    CERN Document Server

    Voit, G M; Bryan, Greg L.

    2001-01-01

    Clusters of galaxies are thought to contain about ten times as much dark matter as baryonic matter. The dark component therefore dominates the gravitational potential of the cluster, and the baryons confined by this potential radiate X-rays with a luminosity that depends mainly on the gas density in the cluster's core. Predictions of the X-rays' properties based on models of cluster formation do not, however, agree with the observations. If the models ignore the condensation of cooling gas into stars and feedback from the associated supernovae, they overestimate the X-ray luminosity because the density of the core gas is too high. An early episode of uniformly distributed supernova feedback could rectify this by heating the uncondensed gas and therefore making it harder to compress into the core, but such a process seems to require an implausibly large number of supernovae. Here we show how radiative cooling of intergalactic gas and subsequent supernova heating conspire to eliminate highly compressible low-en...

  8. Stellar Masses, Star Formation Rates and X-ray Constraints on Galaxies in the Coma Cluster

    Science.gov (United States)

    Hrinda, Greg; Desjardins, T. D.; Hornschemeier, A. E.; Gallagher, S.; Hammer, D.; Miller, N. A.; Ptak, A.; Tzanavaris, P.; Johnson, K. E.; Walker, L.

    2014-01-01

    We report on new measurements of star formation rates and stellar masses in the “infall” region of the nearby Coma cluster of galaxies. This region is approximately 1 Mpc from the cluster core, where relatively gas-rich galaxies are interacting with the hot intracluster medium, providing an important view of the impact of cluster processes on galaxy evolution. We have used infrared and ultraviolet data available from both ground and spaced-based observations to make these measurements. The star formation rates and stellar mass values were verified via comparison with published results in the Coma core as well as the Sloan Digital Sky Survey spectral measurements. The infall region has also been observed by XMM-Newton to faint limits to obtain X-ray luminosities for the galaxies in this field. Specifically, we present X-ray photometry of approximately 20 galaxies with XMM-Newton coverage to constrain the X-ray - SFR correlation in a cluster environment. This project was supported by the Baltimore Excellence in STEM Teaching program via summer internship funding to Hrinda.

  9. Discovery of a 205.89 Hz accreting-millisecond X-ray pulsar in the globular cluster NGC 6440

    CERN Document Server

    Altamirano, D; Heinke, C; Markwardt, C; Strohmayer, T; Linares, M; Wijnands, R; Van der Klis, M; Swank, J

    2009-01-01

    We report the discovery of the second accreting millisecond X-ray pulsar (AMXP) in the globular cluster NGC 6440. Pulsations with a frequency of 205.89 Hz were detected with the Rossi X-Ray Timing Explorer on August 30th and October 1st, 2009, during the decay of ~4 days outburst of a newly X-ray transient source in NGC 6440. By studying the Doppler shift of the pulsation frequency we find that the system is an ultra-compact binary with an orbital period of 57.3 minutes and a projected semi-major axis of 6.22 light-milliseconds. Based on the mass function, we estimate a lower limit to the mass of the companion to be 0.0067 M_sun (assuming a 1.4 M_sun neutron star). This new pulsar shows the shortest outburst recurrence time among AMXPs (~1 month). If this behaviour does not cease, this AMXP has the potential to be one of the best sources in which to study how the binary system and the neutron star spin evolve. Furthermore, the characteristics of this new source indicates that there might exist a population of...

  10. X-ray phase imaging with a laboratory source using selective reflection from a mirror.

    Science.gov (United States)

    Pelliccia, Daniele; Paganin, David M

    2013-04-22

    A novel approach for hard x-ray phase contrast imaging with a laboratory source is reported. The technique is based on total external reflection from the edge of a mirror, aligned to intercept only half of the incident beam. The mirror edge thus produces two beams. The refraction x-rays undergo when interacting with a sample placed before the mirror, causes relative intensity variations between direct and reflected beams. Quantitative phase contrast and pure absorption imaging are demonstrated using this method.

  11. The SPARX Project: R & D Activity Towards X-Rays FEL Sources

    Energy Technology Data Exchange (ETDEWEB)

    Alesini, D.; Bellaveglia, M.; Bertolucci, S.; Biagini, M.E.; Boni, R.; Boscolo, M.; Castellano, M.; Clozza, A.; Di Pirro, G.; Drago, A.; Esposito, A.; Ferrario, M.; Filippetto, D.; Fusco, V.; Gallo, A.; Ghigo, A.; Guiducci, S.; Incurvati, M.; Ligi, C.; Marcellini, F.; Migliorati, M.; /Frascati /ENEA, Frascati /INFN, Milan /INFN, Rome /INFN,

    2005-08-05

    SPARX is an evolutionary project proposed by a collaboration among ENEA-INFN-CNR-Universita di Roma Tor Vergata aiming at the construction of a FELSASE X-ray source in the Tor Vergata Campus. The first phase of the SPARX project, funded by Government Agencies, will be focused on R&D activity on critical components and techniques for future X-ray facilities as described in this paper.

  12. AM CVn systems as optical, X-ray and GWR sources

    NARCIS (Netherlands)

    Yungelson, L.; Nelemans, G.; Portegies Zwart, S.F.; Tovmassian, G.; Sion, E.

    2004-01-01

    We discuss the model for the Galactic sample of the AM CVn systems with P[orb] ≤ 1500 s that can be detected in the optical and/or X-ray bands and may be resolved by the gravitational waves detector LISA. At 3 ≲P ≲ 10 min all detectable systems are X-ray sources. At P ≳ 10 min most systems are only

  13. Populations of Bright X-ray Sources in the Starburst Galaxies NGC 4038/4039

    Institute of Scientific and Technical Information of China (English)

    Xi-Wei Liu; Xiang-Dong Li

    2007-01-01

    Assuming a naive star formation history,we construct synthetic X-ray source populations.using a population synthesis code,for comparison with the observed X-ray luminosity function (XLF) of the interacting galaxies NGC 4038/4039.We have included highand intermediate-mass X-ray binaries.young rotation-powered pulsars and fallback disk-fed black holes in modeling the bright X-ray sources detected.We find that the majority of the X-ray sources are likely to be intermediate-mass X-ray binaries.but for typical binary evolution parameters.the predicted XLF seems to be steeper than observed.We note that the shape of the XLFs depends critically on the existence of XLF break for young populations.and suggest super-Eddington accretion luminosities or the existence of intermediate-mass black holes to account for the high luminosity end and the slope of the XLF in NGC 4038/4039.

  14. 600 eV falcon-linac thomson x-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Crane, J K; LeSage, G P; Ditmire, T; Cross, R; Wharton, K; Moffitt, K; Cowan, T E; Hays, G; Tsai, V; Anderson, G; Shuttlesworth, R; Springer, P

    2000-12-15

    The advent of 3rd generation light sources such as the Advanced Light Source (ALS) at LBL, and the Advanced Photon Source at Argonne, have produced a revolution in x-ray probing of dense matter during the past decade. These machines use electron-synchrotrons in conjunction with undulator stages to produce 100 psec x-ray pulses with photon energies of several kiloelectronvolts (keV). The applications for x-ray probing of matter are numerous and diverse with experiments in medicine and biology, semiconductors and materials science, and plasma and solid state physics. In spite of the success of the 3rd generation light sources there is strong motivation to push the capabilities of x-ray probing into new realms, requiring shorter pulses, higher brightness and harder x-rays. A 4th generation light source, the Linac Coherent Light Source (LCLS), is being considered at the Stanford Linear Accelerator [1]. The LCLS will produce multi-kilovolt x-rays of subpicosecond duration that are 10 orders of magnitude brighter than today's 3rd generation light sources.[1] Although the LCLS will provide unprecedented capability for performing time-resolved x-ray probing of ultrafast phenomena at solid densities, this machine will not be completed for many years. In the meantime there is a serious need for an ultrashort-pulse, high-brightness, hard x-ray source that is capable of probing deep into high-Z solid materials to measure dynamic effects that occur on picosecond time scales. Such an instrument would be ideal for probing the effects of shock propagation in solids using Bragg and Laue diffraction. These techniques can be used to look at phase transitions, melting and recrystallization, and the propagation of defects and dislocations well below the surface in solid materials. [2] These types of dynamic phenomena undermine the mechanical properties of metals and are of general interest in solid state physics, materials science, metallurgy, and have specific relevance to

  15. The spatial clustering of X-ray selected AGN in the XMM-COSMOS field

    CERN Document Server

    Gilli, R; Miyaji, T; Silverman, Joseph; Brusa, M; Mainieri, V; Cappelluti, N; Daddi, E; Porciani, C; Pozzetti, L; Civano, F; Comastri, A; Finoguenov, A; Fiore, F; Salvato, M; Vignali, C; Hasinger, G; Lilly, S; Impey, C; Trump, J; Capak, P; McCracken, H; Scoville, N; Taniguchi, Y; Carollo, C M; Contini, T; Kneib, J -P; Le Fèvre, O; Renzini, A; Scodeggio, M; Bardelli, S; Bolzonella, M; Bongiorno, A; Caputi, K; Cimatti, A; Coppa, G; Cucciati, O; De la Torre, S; de Ravel, L; Franzetti, P; Garilli, B; Iovino, A; Kampczyk, P; Knobel, C; Kovac, K; Lamareille, F; Le Borgne, J F; Le Brun, V; Maier, C; Mignoli, M; Pellò, R; Peng, Y; Montero, E Perez; Ricciardelli, E; Tanaka, M; Tasca, L; Tresse, L; Vergani, D; Zucca, E; Abbas, U; Bottini, D; Cappi, A; Cassata, P; Fumana, M; Guzzo, L; Leauthaud, A; MacCagni, D; Marinoni, C; Memeo, P; Meneux, B; Oesch, P; Scaramella, R; Walcher, J

    2008-01-01

    We study the spatial clustering of 538 X-ray selected AGN in the 2 deg^2 XMM-COSMOS field that are spectroscopically identified to I_{AB} 3 x 10^{10} M_sun) at the same redshift. This suggests that AGN at z~1 are preferentially hosted by massive galaxies, as observed both in the local and in the distant (z~2) Universe. (shortened)

  16. Characteristics of a molybdenum X-pinch X-ray source as a probe source for X-ray diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Zucchini, F.; Chauvin, C.; Combes, P.; Sol, D.; Loyen, A.; Roques, B.; Grunenwald, J. [CEA, DAM, GRAMAT, F-46500 Gramat (France); Bland, S. N. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom)

    2015-03-15

    X-ray emission from a molybdenum X-pinch has been investigated as a potential probe for the high pressure states made in dynamic compression experiments. Studies were performed on a novel 300 kA, 400 ns generator which coupled the load directly to a low inductance capacitor and switch combination. The X-pinch load consisted of 4 crossed molybdenum wires of 13 μm diameter, crossed at an angle of 62°. The load height was 10 mm. An initial x-ray burst generated at the wire crossing point, radiated in the soft x-ray range (hυ < 10 keV). This was followed, 2–5 ns later, by at least one harder x-ray burst (hυ > 10 keV) whose power ranged from 1 to 7 MW. Time integrated spectral measurements showed that the harder bursts were dominated by K-alpha emission; though, a lower level, wide band continuum up to at least 30 keV was also present. Initial tests demonstrated that the source was capable of driving Laue diffraction experiments, probing uncompressed samples of LiF and aluminium.

  17. The Representative XMM-Newton Cluster Structure Survey (REXCESS) of an X-ray Luminosity Selected Galaxy Cluster Sample

    CERN Document Server

    Böhringer, H; Pratt, G W; Arnaud, M; Ponman, T J; Croston, J H; Borgani, S; Bower, R G; Briel, U G; Collins, C A; Donahue, M; Forman, W R; Finoguenov, A; Geller, M J; Guzzo, L; Henry, J P; Kneissl, R; Mohr, J J; Matsushita, K; Mullis, C R; Ohashi, T; Pedersen, K; Pierini, D; Quintana, H; Raychaudhuri, S; Reiprich, T H; Romer, A K; Rosati, P; Sabirli, K; Temple, R F; Viana, P T P; Vikhlinin, A; Voit, G M; Zhang, Y Y

    2007-01-01

    The largest uncertainty for cosmological studies using clusters of galaxies is introduced by our limited knowledge of the statistics of galaxy cluster structure, and of the scaling relations between observables and cluster mass. To improve on this situation we have started an XMM-Newton Large Programme for the in-depth study of a representative sample of 33 galaxy clusters, selected in the redshift range z=0.055 to 0.183 from the REFLEX Cluster Survey, having X-ray luminosities above 0.4 X 10^44 h_70^-2 erg s^-1 in the 0.1 - 2.4 keV band. This paper introduces the sample, compiles properties of the clusters, and provides detailed information on the sample selection function. We describe the selection of a nearby galaxy cluster sample that makes optimal use of the XMM-Newton field-of-view, and provides nearly homogeneous X-ray luminosity coverage for the full range from poor clusters to the most massive objects in the Universe. For the clusters in the sample, X-ray fluxes are derived and compared to the previo...

  18. Optical technologies for extreme-ultraviolet and soft X-ray coherent sources

    CERN Document Server

    Poletto, Luca

    2015-01-01

    The book reviews the most recent achievements in optical technologies for XUV and X-ray coherent sources. Particular attention is given to free-electron-laser facilities, but also to other sources available at present, such as synchrotrons, high-order laser harmonics and X-ray lasers. The optical technologies relevant to each type of source are discussed. In addition, the main technologies used for photon handling and conditioning, namely multilayer mirrors, adaptive optics, crystals and gratings are explained. Experiments using coherent light received during the last decades a lot of attention for the X-ray regime. Strong efforts were taken for the realization of almost fully coherent sources, e.g. the free-electron lasers, both as independent sources in the femtosecond and attosecond regimes and as seeding sources for free-electron-lasers and X-ray gas lasers. In parallel to the development of sources, optical technologies for photon handling and conditioning of such coherent and intense X-ray beams advance...

  19. Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source.

    Science.gov (United States)

    Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

    2014-09-01

    We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

  20. Dark matter distribution in X-ray luminous galaxy clusters with Emergent Gravity

    Science.gov (United States)

    Ettori, S.; Ghirardini, V.; Eckert, D.; Dubath, F.; Pointecouteau, E.

    2017-09-01

    We present the radial distribution of the dark matter in two massive, X-ray luminous galaxy clusters, Abell 2142 and Abell 2319, and compare it with the quantity predicted as apparent manifestation of the baryonic mass in the context of the 'Emergent Gravity' scenario, recently suggested from Verlinde. Thanks to the observational strategy of the XMM-Newton Cluster Outskirt Programme (X-COP), using the X-ray emission mapped with XMM-Newton and the Sunyaev-Zel'dovich signal in the Planck survey, we recover the gas density, temperature and thermal pressure profiles up to ∼R200, allowing us to constrain at an unprecedented level the total mass through the hydrostatic equilibrium equation. We show that, also including systematic uncertainties related to the X-ray-based mass modelling, the apparent 'dark' matter shows a radial profile that has a shape different from the traditional dark matter distribution, with larger discrepancies (by a factor of 2-3) in the inner (r < 200 kpc) cluster's regions and a remarkable agreement only across R500.

  1. The relation between mass and concentration in X-ray galaxy clusters at high redshift

    CERN Document Server

    Amodeo, Stefania; Capasso, Raffaella; Sereno, Mauro

    2016-01-01

    Galaxy clusters are the most recent, gravitationally-bound products of the hierarchical mass accretion over cosmological scales. How the mass is concentrated is predicted to correlate with the total mass in the cluster's halo, with systems at higher mass being less concentrated at given redshift and for any given mass, systems with lower concentration are found at higher redshifts. Through a spatial and spectral X-ray analysis, we reconstruct the total mass profile of 47 galaxy clusters observed with Chandra in the redshift range $0.40.4$, and is well suited to provide the first constraint on the concentration--mass relation at $z>0.7$ from X-ray analysis. Under the assumptions that the distribution of the X-ray emitting gas is spherically symmetric and in hydrostatic equilibrium, we combine the deprojected gas density and spectral temperature profiles through the hydrostatic equilibrium equation to recover the parameters that describe a NFW total mass distribution. The comparison with results from weak lensi...

  2. Quantifying Substructure Measures In X-ray Images of Galaxy Cluster Mergers With SLAM

    Science.gov (United States)

    Chatzikos, Marios; Sarazin, C. L.; O'Shea, B. W.

    2014-01-01

    I use the Simulation Library of Astrophysical galaxy cluster Mergers (SLAM) database to quantify the effects of mergers on X-ray observables. SLAM consists of a set of 156 adiabatic simulations of binary galaxy cluster mergers, that covers 2 orders of magnitude in the mass of the primary cluster, four values for the mass contrast, and four values for the angular momentum of the collision. In this talk I describe results on substructure measures obtained for various viewing angles. I have quantified the substructure in X-ray images using both center shifts and power ratios. Mergers of intermediate mass contrasts produce substructure signals that can persist in X-ray images for at least 1-2 sound crossing times. The amplitude of both measures depends strongly on the initial mass contrast. The measures for major mergers (mass contrast less than 3) appear to depend on the system mass, while for minor mergers (mass contrast between 3 and 10) they are generally independent of the system mass. Neither measure reflects the true dynamical state of the system closely, although the center shifts appear to be a better proxy. Comparisons with the virial and hydrostatic disequilibrium parameters reveal that there is no value of either substructure measure that unambiguously distinguishes merging from relaxing systems. Implications for SZE observations will also be discussed.

  3. Concordance of X-ray cluster data with big bang nucleosynthesis in mixed dark matter models

    Energy Technology Data Exchange (ETDEWEB)

    Strickland, R.W. [University of Chicago, Chicago, Illinois 60637 (United States); Schramm, D.N. [University of Chicago, Chicago, Illinois 60637 (United States)]|[NASA/Fermilab Theoretical Astrophysics Group, Fermilab, Batavia, Illinois 60510 (United States)

    1997-06-01

    If the hot, X-ray-emitting gas in rich clusters forms a fair sample of the universe as in cold dark matter (CDM) models and the universe is at the critical density {Omega}{sub T}=1, then the data appear to imply a baryon fraction {Omega}{sub b,X} ({Omega}{sub b,X}{equivalent_to}{Omega}{sub b} derived from X-ray cluster data), larger than that predicted by big bang nucleosynthesis (BBN). While other systematic effects such as clumping can lower {Omega}{sub b,X}, in this paper we use an elementary analysis to show that a simple admixture of hot dark matter (HDM; low-mass neutrinos) with CDM to yield mixed dark matter shifts {Omega}{sub b,X} down so that significant overlap with {Omega}{sub b} from BBN can occur for H{sub 0}{approx_lt}73kms{sup {minus}1}Mpc{sup {minus}1}, even without invoking the possible aforementioned effects. The overlap interval is slightly larger for lower mass neutrinos since fewer of them cluster on the scale of the hot X-ray gas. We illustrate this result quantitatively in terms of a simple isothermal model. More realistic velocity dispersion profiles, with less centrally peaked density profiles, imply that fewer neutrinos are trapped and thus further increase the interval of overlap. {copyright} {ital 1997} {ital The American Astronomical Society}

  4. Chandra Studies of Unidentified X-ray Sources in the Galactic Bulge

    Science.gov (United States)

    Mori, Hideyuki

    2013-09-01

    We propose to study a complete X-ray sample in the luminosity range of > 10^34 erg s^-1 in the Galactic bulge, including 5 unidentified sources detected in the ROSAT All Sky Survey. Our goal is to obtain a clear picture about X-ray populations in the bulge, by utilizing the excellent Chandra position accuracy leading to unique optical identification together with the X-ray spectral properties. This is a new step toward understanding the formation history of the bulge. Furthermore, because the luminosity range we observe corresponds to a ``missing link'' region ever studied for a neutron star or blackhole X-ray binary, our results are also unique to test accretion disk theories at intermediate mass accretion rates.

  5. A CCD area detector for X-ray diffraction under high pressure for rotating anode source

    Indian Academy of Sciences (India)

    Amar Sinha; Alka B Garg; V Vijayakumar; B K Godwal; S K Sikka

    2000-04-01

    Details of a two-dimensional X-ray area detector developed using a charge coupled device, a image intensifier and a fibre optic taper are given. The detector system is especially optimized for angle dispersive X-ray diffraction set up using rotating anode generator as X-ray source. The performance of this detector was tested by successfully carrying out powder X-ray diffraction measurements on various materials such as intermetallics AuIn2, AuGa2, high material Pd and low scatterer adamantane (C10H16) at ambient conditions. Its utility for quick detection of phase transitions at high pressures with diamond anvil cell is demonstrated by reproducing the known pressure induced structural transitions in RbI, KI and a new structural phase transition in AuGa2 above 10 GPa. Various softwares have also been developed to analyze data from this detector.

  6. Progress Towards A Dedicated Synchrotron Radiation Source For Ultrafast X-Ray Science

    Science.gov (United States)

    Lidia, Steve

    2002-03-01

    We present progress towards the design of a femtosecond synchrotron radiation x-ray source based on a flat-beam rf gun and a recirculating superconducting linac that provides beam to an array of undulators and bend magnets. Optical pulse durations of <100 fs are obtained by a combination of electron pulse compression, transverse temporal correlation of the electrons, and x-ray pulse compression. After an introduction and initial scientific motivation, we cover the following aspects of the design: layout and lattice, ultra-fast x-ray pulse production, flat electron-beam production, the rf gun, rf systems, cryogenic systems, collective effects, photon production, and synchronization of x-ray and laser pulses. We conclude with a summary of issues and areas of development that remain to be addressed.

  7. LUX: a design study for a linac-/laser-based ultrafast x-ray source

    Science.gov (United States)

    Corlett, John N.; Barletta, William A.; DeSantis, Stefano; Doolittle, Larry; Fawley, William M.; Heimann, Philip; Leone, Stephen; Lidia, Steven; Li, Derun; Penn, Gregory; Ratti, Alex; Reinsch, Matheus; Schoenlein, Robert; Staples, John; Stover, Gregory; Virostek, Steve; Wan, Weishi; Wells, Russell; Wilcox, Russell; Wolski, Andy; Wurtele, Jonathan; Zholents, Alexander A.

    2004-11-01

    We describe the design concepts for a potential future source of femtosecond x-ray pulses based on synchrotron radiation production in a recirculating electron linac. Using harmonic cascade free-electron lasers (FEL's) and spontaneous emission in short-period, narrow-gap insertion devices, a broad range of photon energies are available with tunability from EUV to hard x-ray regimes. Photon pulse durations are controllable and range from 10 fs to 200 fs, with fluxes 107-1012 photons per pulse. Full spatial and temporal coherence is obtained for EUV and soft X-rays. A fiber laser master oscillator and stabilized timing distribution scheme are proposed to synchronize accelerator rf systems and multiple lasers throughout the facility, allowing timing synchronization between sample excitation and X-ray probe of approximately 20-50 fs.

  8. Initial feasibility study of a dedicated synchrotron radiation light source for ultrafast X-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, John N.; DeSantis, S.; Hartman, N.; Heimann, P.; LaFever, R.; Li, D.; Padmore, H.; Rimmer, R.; Robinson, K.; Schoenlein, R.; Tanabe, J.; Wang, S.; Zholents, A.; Kairan, D.

    2001-10-26

    We present an initial feasibility summary of a femtosecond synchrotron radiation x-ray source based on a flat-beam rf gun and a recirculating superconducting linac that provides beam to an array of undulators and bend magnets. Optical pulse durations of < 100 fs are obtained by a combination of electron pulse compression, transverse temporal correlation of the electrons, and x-ray pulse compression. After an introduction and initial scientific motivation, we cover the following aspects of the design: layout and lattice, ultra-fast x-ray pulse production, flat electron-beam production, the rf gun, rf systems, cryogenic systems, collective effects, photon production, and synchronization of x-ray and laser pulses. We conclude with a summary of issues and areas of development that remain to be addressed.

  9. Calibration Of A KrF Laser-Plasma Source For X-Ray Microscopy Applications

    Science.gov (United States)

    Turcu, I. C. E.; O'Neill, F.; Zammit, U.; Al-Hadithi, Y.; Eason, R. W.; Rogayski, A. M.; Hills, C. P. B.; Michette, A. G.

    1988-02-01

    Plasma X-ray sources for biological microscopy in the water-window have been produced by focusing tige 200 3, 50 ns Sprit q KrF laser onto carbon targets at irradiance between 2.2 x 10" W/cm4 and 3.7 x 10i3W/cm. Absolute measurements of X-ray production have been made using a calibrated, vacuum X-ray diode detector. A peak conversion efficiency . 10% is measured from KrF laseri)Tight tcto wate-window X-rays at 280 eV < hv < 530 eV for a target irradiance . 1 x x 10 W/cm'. Some measurements with gold and tungsten targets give conversion efficiencies 2$25% at a similar laser irradiance.

  10. High contrast Kr gas jet K alpha x-ray source for high energy density physics experiments.

    Science.gov (United States)

    Kugland, N L; Neumayer, P; Döppner, T; Chung, H-K; Constantin, C G; Girard, F; Glenzer, S H; Kemp, A; Niemann, C

    2008-10-01

    A high contrast 12.6 keV Kr K alpha source has been demonstrated on the petawatt-class Titan laser facility using strongly clustering Kr gas jet targets. The contrast ratio (K alpha to continuum) is 65, with a competitive ultrashort pulse laser to x-ray conversion efficiency of 10(-5). Filtered shadowgraphy indicates that the Kr K alpha and K beta x rays are emitted from a roughly 1x2 mm(2) emission volume, making this source suitable for area backlighting and scattering. Spectral calculations indicate a typical bulk electron temperature of 50-70 eV (i.e., mean ionization state 13-16), based on the observed ratio of K alpha to K beta. Kr gas jets provide a debris-free high energy K alpha source for time-resolved diagnosis of dense matter.

  11. Development and characterization of a tunable ultrafast X-ray source via inverse-Compton-scattering

    Energy Technology Data Exchange (ETDEWEB)

    Jochmann, Axel

    2014-07-01

    Ultrashort, nearly monochromatic hard X-ray pulses enrich the understanding of the dynamics and function of matter, e.g., the motion of atomic structures associated with ultrafast phase transitions, structural dynamics and (bio)chemical reactions. Inverse Compton backscattering of intense laser pulses from relativistic electrons not only allows for the generation of bright X-ray pulses which can be used in a pump-probe experiment, but also for the investigation of the electron beam dynamics at the interaction point. The focus of this PhD work lies on the detailed understanding of the kinematics during the interaction of the relativistic electron bunch and the laser pulse in order to quantify the influence of various experiment parameters on the emitted X-ray radiation. The experiment was conducted at the ELBE center for high power radiation sources using the ELBE superconducting linear accelerator and the DRACO Ti:sapphire laser system. The combination of both these state-of-the-art apparatuses guaranteed the control and stability of the interacting beam parameters throughout the measurement. The emitted X-ray spectra were detected with a pixelated detector of 1024 by 256 elements (each 26μm by 26μm) to achieve an unprecedented spatial and energy resolution for a full characterization of the emitted spectrum to reveal parameter influences and correlations of both interacting beams. In this work the influence of the electron beam energy, electron beam emittance, the laser bandwidth and the energy-anglecorrelation on the spectra of the backscattered X-rays is quantified. A rigorous statistical analysis comparing experimental data to ab-initio 3D simulations enabled, e.g., the extraction of the angular distribution of electrons with 1.5% accuracy and, in total, provides predictive capability for the future high brightness hard X-ray source PHOENIX (Photon electron collider for Narrow bandwidth Intense X-rays) and potential all optical gamma-ray sources. The results

  12. The extended ROSAT-ESO Flux Limited X-ray Galaxy Cluster Survey (REFLEX II) IV. X-ray Luminosity Function and First Constraints on Cosmological Parameters

    CERN Document Server

    Böhringer, H; Collins, C A

    2014-01-01

    The X-ray luminosity function is an important statistic of the census of galaxy clusters and an important means to probe the cosmological model of our Universe. Based on our recently completed REFLEX II cluster sample we construct the X-ray luminosity function of galaxy clusters for several redshift slices from $z = 0$ to $z = 0.4$ and discuss its implications. We find no significant signature of redshift evolution of the luminosity function in the redshift interval. We provide the results of fits of a parameterized Schechter function and extensions of it which provide a reasonable characterization of the data. Using a model for structure formation and galaxy cluster evolution we compare the observed X-ray luminosity function with predictions for different cosmological models. For the most interesting constraints for the cosmological parameters $\\Omega_m$ and $\\sigma_8$ we obatain $\\Omega_m \\sim 0.27 \\pm 0.03$ and $\\sigma_8 \\sim 0.80 \\pm 0.03$ based on the statistical uncertainty alone. Marginalizing over the...

  13. LUX — A Recirculating Linac-based Ultrafast X-ray Source

    Science.gov (United States)

    Corlett, J. N.; Barletta, W. A.; DeSantis, S.; Doolittle, L.; Fawley, W. M.; Green, M. A.; Heimann, P.; Leone, S. R.; Lidia, S.; Li, D.; Parmigiani, F.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Zholents, A.

    2004-05-01

    We describe the design of a proposed source of ultra-fast synchrotron radiation x-ray pulses based on a recirculating superconducting linac, with an integrated array of ultrafast laser systems. The source produces x-ray pulses with duration of 10-50 fs at a 10 kHz repetition rate, with tunability from EUV to hard x-ray regimes, and optimized for the study of ultra-fast dynamics. A high-brightness rf photocathode provides electron bunches. An injector linac accelerates the beam to the 100 MeV range, and is followed by four passes through a 700 MeV recirculating linac. Ultrafast hard x-ray pulses are obtained by a combination of electron bunch manipulation, transverse temporal correlation of the electrons, and x-ray pulse compression. EUV and soft x-ray pulses as short as 10 fs are generated in a harmonic-cascade free electron laser scheme. We describe the facility major systems and peformance.

  14. Upgrade of X-band thermionic cathode RF gun for Compton scattering X-ray source

    Science.gov (United States)

    Taniguchi, Yoshihiro; Sakamoto, Fumito; Natsui, Takuya; Yamamoto, Tomohiko; Hashimoto, Eiko; Lee, KiWoo; Uesaka, Mitsuru; Yoshida, Mitsuhiro; Higo, Toshiyasu; Fukuda, Shigeki; Akemoto, Mitsuo

    2009-09-01

    A Compton scattering X-ray source consisting of an X-band (11.424 GHz) electron linear accelerator (linac) and Q-switched Nd: YAG laser is currently under development at the University of Tokyo. Monochromatic X-rays are required for a variety of medical and biological applications. The X-ray source produces monochromatic X-rays via collision between a 35-MeV multi-bunch (104 bunches in a 1 μs RF pulse) electron beam and 1.4 J/10 ns (532 nm) Nd: YAG laser pulse. The linac uses an X-band 3.5-cell thermionic cathode RF gun and an alpha magnet as an injector. Until now, electron beam generation (2 MeV, 1 pC/bunch at the exit of the injector), beam acceleration, and X-ray generation have been verified. In order to increase X-ray energy and intensity, we have completed the design and construction of a new RF gun with relevant modifications in some structures. In this paper, we describe the details of the concepts of designing a new RF gun and discuss future works.

  15. Development of a Sub-Picosecond Tunable X-Ray Source at the LLNL Electron Linac

    Energy Technology Data Exchange (ETDEWEB)

    Slaughter, D; Springer, P; Le Sage, G; Crane, J; Ditmire, T; Cowan, T; Anderson, S G; Rosenzweig, J B

    2001-08-31

    The use of ultrafast laser pulses to generate very high brightness, ultra short (fs to ps) pulses of x-rays is a topic of great interest to the x-ray user community. In principle, femtosecond-scale pump-probe experiments can be used to temporally resolve structural dynamics of materials on the time scale of atomic motion. The development of sub-ps x-ray pulses will make possible a wide range of materials and plasma physics studies with unprecedented time resolution. A current project at LLNL will provide such a novel x-ray source based on Thomson scattering of high power, short laser pulses with a high peak brightness, relativistic electron bunch. The system is based on a 5 mm-mrad normalized emittance photoinjector, a 100 MeV electron RF linac, and a 300 mJ, 35 fs solid-state laser system. The Thomson x-ray source produces ultra fast pulses with x-ray energies capable of probing into high-Z metals, and a high flux per pulse enabling single shot experiments. The system will also operate at a high repetition rate ({approx} 10 Hz).

  16. Galaxy Cluster Scaling Relations between Bolocam Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements

    CERN Document Server

    Czakon, N G; Mantz, A; Golwala, S R; Downes, T P; Koch, P M; Lin, K -Y; Molnar, S M; Moustakas, L A; Mroczkowski, T; Pierpaoli, E; Shitanishi, J A; Siegel, S; Umetsu, K

    2014-01-01

    We present scaling relations between the integrated Sunyaev-Zel'dovich Effect (SZE) signal, $Y_{\\rm SZ}$, its X-ray analogue, $Y_{\\rm X}$$\\equiv$$M_{\\rm gas}$$T_{\\rm X}$, and total mass, $M_{\\rm tot}$, for the 45 galaxy clusters in the Bolocam X-ray-SZ (BOXSZ) sample. All parameters are integrated within $r_{2500}$. $Y_{2500}$ values are measured using SZE data collected with Bolocam, operating at 140 GHz at the Caltech Submillimeter Observatory (CSO). The temperature, $T_{\\rm X}$, and mass, $M_{\\rm gas,2500}$, of the intracluster medium are determined using X-ray data collected with \\emph{Chandra}, and $M_{\\rm tot}$ is derived from $M_{\\rm gas}$ using a constant gas mass fraction. Our analysis accounts for several potential sources of bias, including: selection effects, contamination from radio point sources, and the loss of SZE signal due to noise filtering and beam-smoothing effects. We measure the $Y_{2500}$-$Y_{\\rm X}$ scaling to have a logarithmic slope of $0.84\\pm0.07$, and a fractional intrinsic scatt...

  17. Faint Ultraviolet Objects in the Core of M13 Optical Counterparts of the Low Luminosity X-ray Source?

    CERN Document Server

    Ferraro, F R; Pecci, F F; Rood, R T; Dorman, B; Ferraro, Francesco R.; Paltrinieri, Barbara; Pecci, Flavio Fusi; Rood, Robert T.; Dorman, Ben

    1997-01-01

    The core of the galactic globular cluster M13 (NGC 6205) has been observed with WFPC2 on the Hubble Space Telescope through visual, blue and mid- and far-UV filters in a programme devoted to study the UV population in a sample of Galactic globular clusters. In the UV Color Magnitude Diagrams derived from the HST images we have discovered three faint objects with a strong UV excess, which lie significantly outside the main loci defined by more than 12,000 normal cluster stars. The positions of two of the UV stars are nearly coincident (7" & 1") to those of a low luminosity X-ray source recently found in the core of M13 and to a 3.5-sigma peak in the X-ray contour map. We suggest that the UV stars are physically connected to the X-ray emission. The UV stars are very similar to the quiescent nova in the globular cluster M80, and they might be a, perhaps new, subclass of cataclysmic variable.

  18. Old and Young X-ray Point Source Populations in Nearby Galaxies

    CERN Document Server

    Colbert, E; Ptak, A; Strickland, D K

    2004-01-01

    We analyzed 1441 Chandra X-ray point sources in 32 nearby galaxies. The total point-source X-ray luminosity L_XP is well correlated with B, K, and FIR+UV luminosities of spiral host galaxies, and with the B and K luminosities for ellipticals. This suggests an intimate connection between L_XP and both the old and young stellar populations, for which K and FIR+UV luminosities are proxies for the galaxy mass M and star-formation rate SFR. We derive proportionality constants 1.3E29 erg/s/Msol and 0.7E39 erg/s/(Msol/yr), which can be used to estimate the old and young components from M and SFR, respectively. The cumulative X-ray luminosity functions for the point sources have quite different slopes for the spirals (gamma ~= 0.5-0.8) and ellipticals (gamma ~= 1.4), implying *the most luminous point sources dominate L_XP* for the spirals. Most of the point sources have X-ray colors that are consistent with either LMXBs or Ultraluminous X-ray sources (ULXs a.k.a. IXOs) and we rule out classical HMXBs (e.g. neutron-st...

  19. Chandra Observation of the X-Ray Source Population of NGC 6946

    CERN Document Server

    Holt, S S; Hwang, U; Petre, R

    2003-01-01

    We present the results of a study of discrete X-ray sources in NGC 6946 using a deep Chandra ACIS observation. Based on the slope of the log N-log S distribution and the general correlation of sources with the spiral arms, we infer that the overall discrete source sample in NGC 6946 is dominated by high mass X-ray binaries, in contrast to the source distributions in M31 and the Milky Way. This is consistent with the higher star formation rate in NGC 6946 than in those galaxies. We find that the strong X-ray sources in the region of the galactic center do not correlate in detail with images of the region in the near-IR, although one of them may be coincident with the galactic center. The non-central ultra-luminous X-ray source in NGC 6946, previously identified with a supernova remnant, has an X-ray spectrum and luminosity that is inconsistent with either a traditional pulsar wind nebula or a blast wave remnant.

  20. A radio survey of supersoft, persistent and transient X-ray sources in the Magellanic Clouds

    CERN Document Server

    Fender, R P; Tzioumis, A K

    1998-01-01

    We present a radio survey of X-ray sources in the Large and Small Magellanic clouds with the Australia Telescope Compact Array at 6.3 and 3.5 cm. Specifically, we have observed the fields of five LMC and two SMC supersoft X-ray sources, the X-ray binaries LMC X-1, X-2, X-3 & X-4, the X-ray transient Nova SMC 1992, and the soft gamma-ray repeater SGR 0525-66. None of the targets are detected as point sources at their catalogued positions. In particular, the proposed supersoft jet source RXJ 0513-69 is not detected, placing constraints on its radio luminosity compared to Galactic jet sources. Limits on emission from the black hole candidate systems LMC X-1 and X-3 are consistent with the radio behaviour of persistent Galactic black hole X-ray binaries, and a previous possible radio detection of LMC X-1 is found to almost certainly be due to nearby field sources. The SNR N49 in the field of SGR 0525-66 is mapped at higher resolution than previously, but there is still no evidence for any enhanced emission or...

  1. Compact source of narrowband and tunable X-rays for radiography

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Sudeep, E-mail: sbanejee2@unl.edu [Department of Physics and Astronomy, University of Nebraska, Lincoln, NE 68516 (United States); Chen, Shouyuan; Powers, Nathan; Haden, Daniel; Liu, Cheng; Golovin, G.; Zhang, Jun; Zhao, Baozhen [Department of Physics and Astronomy, University of Nebraska, Lincoln, NE 68516 (United States); Clarke, S.; Pozzi, S. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Silano, J.; Karwowski, H. [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599 (United States); Umstadter, Donald [Department of Physics and Astronomy, University of Nebraska, Lincoln, NE 68516 (United States)

    2015-05-01

    We discuss the development of a compact X-ray source based on inverse-Compton scattering with a laser-driven electron beam. This source produces a beam of high-energy X-rays in a narrow cone angle (5–10 mrad), at a rate of 10{sup 8} photons-s{sup −1}. Tunable operation of the source over a large energy range, with energy spread of ∼50%, has also been demonstrated. Photon energies >10 MeV have been obtained. The narrowband nature of the source is advantageous for radiography with low dose, low noise, and minimal shielding.

  2. Low X-Ray Luminosity Galaxy Clusters: Main goals, sample selection, photometric and spectroscopic observations

    CERN Document Server

    Castellón, J L Nilo; Lambas, D García; Valotto, Carlos; Mill, A L O'; Cuevas, H; Carrasco, E R; Ramírez, A; Astudillo, J M; Ramos, F; Jaque, M; Ulloa, N; Órdenes, Y

    2016-01-01

    We present the study of nineteen low X-ray luminosity galaxy clusters (L$_X \\sim$ 0.5--45 $\\times$ $10^{43}$ erg s$^{-1}$), selected from the ROSAT Position Sensitive Proportional Counters (PSPC) Pointed Observations (Vikhlinin et al. 1998) and the revised version of Mullis et al. (2003) in the redshift range of 0.16 to 0.7. This is the introductory paper of a series presenting the sample selection, photometric and spectroscopic observations and data reduction. Photometric data in different passbands were taken for eight galaxy clusters at Las Campanas Observatory; three clusters at Cerro Tololo Interamerican Observatory; and eight clusters at the Gemini Observatory. Spectroscopic data were collected for only four galaxy clusters using Gemini telescopes. With the photometry, the galaxies were defined based on the star-galaxy separation taking into account photometric parameters. For each galaxy cluster, the catalogues contain the PSF and aperture magnitudes of galaxies within the 90\\% completeness limit. They...

  3. The X-Ray Binary Population of the Nearby Dwarf Starburst Galaxy IC 10: Variable and Transient X-Ray Sources

    Science.gov (United States)

    Laycock, Silas; Cappallo, Rigel; Williams, Benjamin F.; Prestwich, Andrea; Binder, Breanna; Christodoulou, Dimitris M.

    2017-02-01

    We have monitored the Cassiopeia dwarf galaxy (IC 10) in a series of 10 Chandra ACIS-S observations to capture its variable and transient X-ray source population, which is expected to be dominated by High Mass X-ray Binaries (HMXBs). We present a sample of 21 X-ray sources that are variable between observations at the 3σ level, from a catalog of 110 unique point sources. We find four transients (flux variability ratio greater than 10) and a further eight objects with ratios >5. The observations span the years 2003–2010 and reach a limiting luminosity of >1035 erg s‑1, providing sensitivity to X-ray binaries in IC 10 as well as flare stars in the foreground Milky Way. The nature of the variable sources is investigated from light curves, X-ray spectra, energy quantiles, and optical counterparts. The purpose of this study is to discover the composition of the X-ray binary population in a young starburst environment. IC 10 provides a sharp contrast in stellar population age (<10 My) when compared to the Magellanic Clouds (40–200 My) where most of the known HMXBs reside. We find 10 strong HMXB candidates, 2 probable background Active Galactic Nuclei, 4 foreground flare-stars or active binaries, and 5 not yet classifiable sources. Complete classification of the sample requires optical spectroscopy for radial velocity analysis and deeper X-ray observations to obtain higher S/N spectra and search for pulsations. A catalog and supporting data set are provided.

  4. The relation between mass and concentration in X-ray galaxy clusters at high redshift

    Science.gov (United States)

    Amodeo, S.; Ettori, S.; Capasso, R.; Sereno, M.

    2016-05-01

    Context. Galaxy clusters are the most recent, gravitationally bound products of the hierarchical mass accretion over cosmological scales. How the mass is concentrated is predicted to correlate with the total mass in the halo of the cluster, wherein systems at higher mass are less concentrated at given redshift and, for any given mass, systems with lower concentration are found at higher redshifts. Aims: Through a spatial and spectral X-ray analysis, we reconstruct the total mass profile of 47 galaxy clusters observed with Chandra in the redshift range 0.4 0.4, and is well suited to providing the first constraint on the concentration-mass relation at z> 0.7 from X-ray analysis. Methods: Under the assumption that the distribution of the X-ray emitting gas is spherically symmetric and in the hydrostatic equilibrium with the underlined gravitational potential, we combine the deprojected gas density and spectral temperature profiles through the hydrostatic equilibrium equation to recover the parameters that describe a Navarro-Frenk-White total mass distribution. The comparison with results from weak-lensing analysis reveals a very good agreement both for masses and concentrations. The uncertainties are however too large to make any robust conclusion about the hydrostatic bias of these systems. Results: The distribution of concentrations is well approximated by a log-normal function in all the mass and redshift ranges investigated. The relation is well described by the form c ∝ MB(1 + z)C with B = -0.50 ± 0.20, C = 0.12 ± 0.61 (at 68.3% confidence). This relation is slightly steeper than that predicted by numerical simulations (B ~ -0.1) and does not show any evident redshift evolution. We obtain the first constraints on the properties of the concentration-mass relation at z> 0.7 from X-ray data, showing a reasonable good agreement with recent numerical predictions.

  5. Planck early results: Statistical analysis of Sunyaev-Zeldovich scaling relations for X-ray galaxy clusters

    CERN Document Server

    Aghanim, N; Ashdown, M; Aumont, J; Baccigalupi, C; Balbi, A; Banday, A J; Barreiro, R B; Bartelmann, M; Bartlett, J G; Battaner, E; Benabed, K; Benoît, A; Bernard, J -P; Bersanelli, M; Bhatia, R; Bock, J J; Bonaldi, A; Bond, J R; Borrill, J; Bouchet, F R; Brown, M L; Bucher, M; Burigana, C; Cabella, P; Cardoso, J -F; Catalano, A; Cayón, L; Challinor, A; Chamballu, A; Chary, R -R; Chiang, L -Y; Chiang, C; Chon, G; Christensen, P R; Churazov, E; Clements, D L; Colafrancesco, S; Colombi, S; Couchot, F; Coulais, A; Crill, B P; Cuttaia, F; Da Silva, A; Dahle, H; Danese, L; de Bernardis, P; de Gasperis, G; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Désert, F -X; Diego, J M; Dolag, K; Donzelli, S; Doré, O; Dörl, U; Douspis, M; Dupac, X; Efstathiou, G; En\\sslin, T A; Finelli, F; Flores, I; Forni, O; Frailis, M; Franceschi, E; Fromenteau, S; Galeotta, S; Ganga, K; Génova-Santos, R T; Giard, M; Giardino, G; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Harrison, D; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hovest, W; Hoyland, R J; Huffenberger, K M; Jaffe, A H; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knox, L; Kurki-Suonio, H; Lagache, G; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lawrence, C R; Leach, S; Leonardi, R; Linden-V\\ornle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; MacTavish, C J; Maffei, B; Maino, D; Mandolesi, N; Mann, R; Maris, M; Marleau, F; Martínez-González, E; Masi, S; Matarrese, S; Matthai, F; Mazzotta, P; Melchiorri, A; Melin, J -B; Mendes, L; Mennella, A; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, A; Naselsky, P; Natoli, P; Netterfield, C B; N\\orgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; Osborne, S; Pajot, F; Pasian, F; Patanchon, G; Perdereau, O; Perotto, L; Perrotta, F; Piacentini, F; Piat, M; Pierpaoli, E; Piffaretti, R; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Poutanen, T; Pratt, G W; Prézeau, G; Prunet, S; Puget, J -L; Rebolo, R; Reinecke, M; Renault, C; Ricciardi, S; Riller, T; Ristorcelli, I; Rocha, G; Rosset, C; Rubiño-Martín, J A; Rusholme, B; Sandri, M; Santos, D; Schaefer, B M; Scott, D; Seiffert, M D; Smoot, G F; Starck, J -L; Stivoli, F; Stolyarov, V; Sunyaev, R; Sygnet, J -F; Tauber, J A; Terenzi, L; Toffolatti, L; Tomasi, M; Tristram, M; Tuovinen, J; Valenziano, L; Vibert, L; Vielva, P; Villa, F; Vittorio, N; Wandelt, B D; White, S D M; White, M; Yvon, D; Zacchei, A; Zonca, A

    2011-01-01

    All-sky data from the Planck survey and the Meta-Catalogue of X-ray detected Clusters of galaxies (MCXC) are combined to investigate the relationship between the thermal Sunyaev-Zeldovich (SZ) signal and X-ray luminosity. The sample comprises ~ 1600 X-ray clusters with redshifts up to ~ 1 and spanning a wide range in X-ray luminosity. The SZ signal is extracted for each object individually and the statistical significance of the measurement is maximised by averaging the SZ signal in bins of X-ray luminosity, total mass or redshift. The SZ signal is detected at very high significance over more than 2 decades in X-ray luminosity (10^43 erg/s < L_500 E(z)^-7/3 < 2 X 10^45 erg/s). The relation between intrinsic SZ signal and X-ray luminosity is investigated and the measured SZ signal is compared to values predicted from X-ray data. Planck measurements and X-ray based predictions are found to be in excellent agreement over the whole explored luminosity range. No significant deviation from standard evolution ...

  6. A JEM-X Catalog of X-ray Sources

    DEFF Research Database (Denmark)

    Westergaard, Niels Jørgen Stenfeldt

    2009-01-01

    . A search for weaker, persistent, sources has been done in deep mosaic images that have been produced with all available observations for a large number of sky regions. The two resulting catalogs hold 158 and 179 sources respectively, but the combined catalog consists of 209 sources. This catalog can...... be downloaded as a FITS binary table file with source information such as names, positions, and fluxes at the PoS web page for the conference....

  7. Common-source TLD and RADFET characterization of Co-60, Cs-137, and x-ray irradiation sources

    Energy Technology Data Exchange (ETDEWEB)

    Simons, M. [Research Triangle Inst., Research Triangle Park, NC (United States); Pease, R.L. [RLP Research, Albuquerque, NM (United States); Fleetwood, D.M. [Sandia National Labs., Albuquerque, NM (United States)] [and others

    1997-06-01

    Dose enhancement and dose rate were measured in more than a dozen gamma sources using pMOS RADFETs and TLDs from two independent sources. ARACOR X-ray dose rates were calibrated using single- and dual-dielectric RADFETs.

  8. Optical and X-ray profiles in the REXCESS sample of galaxy clusters

    CERN Document Server

    Holland, John G; Chon, Gayoung; Pierini, Daniele

    2015-01-01

    Galaxy clusters' structure, dominated by dark matter, is traced by member galaxies in the optical and hot intra-cluster medium (ICM) in X-rays. We compare the radial distribution of these components and determine the mass-to-light ratio vs. system mass relation. We use 14 clusters from the REXCESS sample which is representative of clusters detected in X-ray surveys. Photometric observations with the Wide Field Imager on the 2.2m MPG/ESO telescope are used to determine the number density profiles of the galaxy distribution out to $r_{200}$. These are compared to electron density profiles of the ICM obtained using XMM-Newton, and dark matter profiles inferred from scaling relations and an NFW model. While red sequence galaxies trace the total matter profile, the blue galaxy distribution is much shallower. We see a deficit of faint galaxies in the central regions of massive and regular clusters, and strong suppression of bright and faint blue galaxies in the centres of cool-core clusters, attributable to ram pre...

  9. Analysis of coronal and chromospheric hard X-ray sources in an eruptive solar flare

    Science.gov (United States)

    Zimovets, Ivan; Golovin, Dmitry; Livshits, Moisey; Vybornov, Vadim; Sadykov, Viacheslav; Mitrofanov, Igor

    We have analyzed hard X-ray emission of an eruptive solar flare on 3 November 2010. The entire flare region was observed by the STEREO-B spacecraft. This gave us an information that chromospheric footpoints of flare magnetic loops were behind the east solar limb for an earth observer. Hard X-ray emission from the entire flare region was detected by the High Energy Neutron Detector (HEND) onboard the 2001 Mars Odyssey spacecraft while hard X-rays from the coronal part of the flare region were detected by the RHESSI. This rare situation has allowed us to investigate both coronal and chromospheric sources of hard X-ray emission separately. Flare impulsive phase was accompanied by eruption of a magnetic flux rope and formation of a plasmoid detected by the AIA/SDO in the EUV range. Two coronal hard X-ray sources (S_{1} and S_{2}) were detected by the RHESSI. The upper source S_{1} coincided with the plasmoid and the lower source S_{2} was near the tops of the underlying flare loops that is in accordance with the standard model of eruptive flares. Imaging spectroscopy with the RHESSI has allowed to measure energetic spectra of hard X-ray emission from the S_{1} and S_{2} sources. At the impulsive phase peak they have power-law shape above ≈ 15 keV with spectral slopes gamma_{S_{1}}=3.46 ± 1.58 and gamma_{S_{2}}=4.64 ± 0.12. Subtracting spatially integrated spectrum of coronal hard X-ray emission measured by the RHESSI from the spectrum measured by the HEND we found spectrum of hard X-rays emitted from the footpoints of the flare loops (source S_{0}). This spectrum has a power-law shape with gamma_{S_{0}}=2.21 ± 0.57. It is shown that it is not possible to explain the measured spectra of the S_{2} and S_{0} sources in frames of the thin and thick target models respectively if we assume that electrons were accelerated in the energy release site situated below the plasmoid and above the flare loops as suggested by the standard flare model. To resolve the contradiction

  10. Ultraluminous X-ray Sources as Intermediate Mass Black Holes Fed by Tidally Captured Stars

    CERN Document Server

    Hopman, C; Alexander, T; Hopman, Clovis; Zwart, Simon F. Portegies; Alexander, Tal

    2004-01-01

    The nature of ultraluminous X-ray sources (ULXs) is presently unknown. A possible explanation is that they are accreting intermediate mass black holes (IBHs) that are fed by Roche lobe overflow from a tidally captured stellar companion. We show that a star can circularize around an IBH without being destroyed by tidal heating (in contrast to the case of M_bh> 10^6 M_sun massive black holes in galactic centers, where survival is unlikely). We find that the capture and circularization rate is of the order of 5 \\times 10^-8 yr^-1, almost independently of the cluster's relaxation time. We follow the luminosity evolution of the binary system during the main sequence Roche lobe overflow phase and show it can maintain ULX-like luminosities for >10 Myr. In particular, we show that the ULX in the young cluster MGG-11 in star-burst galaxy M82, which possibly harbors an IBH, is well explained by this mechanism, and we predict that \\gtrsim 10% of similar clusters with IBHs have a tidally captured circularized star. The c...

  11. SIGMA discovery of a transient hard X-ray source in the galactic center region.

    Science.gov (United States)

    Vargas, M.; Goldwurm, A.; Paul, J.; Denis, M.; Borrel, V.; Bouchet, L.; Roques, J. P.; Jourdain, E.; Trudolyubov, S.; Gilfanov, M.; Churazov, E.; Sunyaev, R.; Khavenson, N.; Dyachkov, A.; Novikov, B.; Chulkov, I.

    1996-09-01

    A new X-ray transient source, GRS 1730-312 (=KS 1730-312), was discovered by the hard X-ray/soft γ-ray coded mask telescope SIGMA/GRANAT in the Galactic Center region during observations performed in September 1994. The flare started on September 22 and lasted approximately 3days, during which the source became the brightest object of the region at energies above 35keV. The average 35-200keV spectrum can be described by a power law with photon index of -2.5 or by a thermal bremsstrahlung model with kT_e_=~70keV. SIGMA data have been found consistent with the spectral shape and with the spectral evolution observed by the TTM/Mir-Kvant telescope at lower energies. This new source belongs to the population of hard X-ray sources already detected by SIGMA in the direction of the Galactic Bulge region.

  12. Luminous X-ray sources in spiral and star-forming galaxies.

    Science.gov (United States)

    Ward, Martin

    2002-09-15

    For studies of discrete X-ray source populations in nearby galaxies, high spatial resolution is a key to making progress. Now, for the first time, using the Chandra X-ray observatory, we are able to study these source populations in detail for galaxies beyond M31 and our local group galaxies. Analysis of accretion-driven and supernova-related discrete sources provides a new perspective on the evolution of galactic stellar populations, as well as giving insights into the physical mechanisms operating in individual cases. A particularly intriguing area, which we are only just beginning to address, is the nature of the most X-ray-luminous sources that are being discovered in many spiral and star-forming galaxies.

  13. AMI observations of 10 CLASH galaxy clusters: SZ and X-ray data used together to determine cluster dynamical states

    Science.gov (United States)

    Rumsey, Clare; Olamaie, Malak; Perrott, Yvette C.; Russell, Helen R.; Feroz, Farhan; Grainge, Keith J. B.; Handley, Will J.; Hobson, Michael P.; Saunders, Richard D. E.; Schammel, Michel P.

    2016-07-01

    Using Arcminute Microkelvin Imager (AMI) Sunyaev-Zel'dovich (SZ) observations towards 10 CLASH (Cluster Lensing and Supernova Survey with Hubble) clusters, we investigate the influence of cluster mergers on observational galaxy cluster studies. Although selected to be largely relaxed, there is disagreement in the literature on the dynamical states of CLASH sample members. We analyse our AMI data in a fully Bayesian way to produce estimated cluster parameters and consider the intrinsic correlations in our Navarro, Frenk and White/generalized Navarro, Frenk and White-based model. Varying pressure profile shape parameters, illustrating an influence of mergers on scaling relations, induces small deviations from the canonical self-similar predictions - in agreement with simulations of Poole et al. (2007) who found that merger activity causes only small scatter perpendicular to the relations. We demonstrate this effect observationally using the different dependences of SZ and X-ray signals to ne that cause different sensitivities to the shocking and/or fractionation produced by mergers. Plotting YX-Mgas relations (where YX = MgasT) derived from AMI SZ and from Chandra X-ray gives ratios of AMI and Chandra YX and Mgas estimates that indicate movement of clusters along the scaling relation, as predicted by Poole et al. (2007). Clusters that have moved most along the relation have the most discrepant TSZ and TX estimates: all the other clusters (apart from one) have SZ and X-ray estimates of Mgas, T and YX that agree within r500. We use SZ versus X-ray discrepancies in conjunction with Chandra maps and TX profiles, making comparisons with simulated cluster merger maps in Poole et al. (2006) to identify disturbed members of our sample and estimate merger stages.

  14. Developing small vacuum spark as an x-ray source for calibration of an x-ray focusing crystal spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ghomeishi, Mostafa; Adikan, Faisal Rafiq Mahamd [Photonic Research Group, Department of Electrical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Karami, Mohammad [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2012-10-15

    A new technique of x-ray focusing crystal spectrometers' calibration is the desired result. For this purpose the spectrometer is designed to register radiated copper K{alpha} and K{beta} lines by using a flat {alpha}-quartz crystal. This experiment uses pre-breakdown x-ray emissions in low vacuum of about 2.5-3 mbar. At this pressure the pinch will not form so the plasma will not radiate. The anode material is copper and the capacity of the capacitor bank is 22.6 nF. This experiment designed and mounted a repetitive triggering system to save the operator time making hundreds of shots. This emission amount is good for calibration and geometrical adjustment of an optical crystal x-ray focusing spectrometer.

  15. Developing small vacuum spark as an x-ray source for calibration of an x-ray focusing crystal spectrometer.

    Science.gov (United States)

    Ghomeishi, Mostafa; Karami, Mohammad; Adikan, Faisal Rafiq Mahamd

    2012-10-01

    A new technique of x-ray focusing crystal spectrometers' calibration is the desired result. For this purpose the spectrometer is designed to register radiated copper Kα and Kβ lines by using a flat α-quartz crystal. This experiment uses pre-breakdown x-ray emissions in low vacuum of about 2.5-3 mbar. At this pressure the pinch will not form so the plasma will not radiate. The anode material is copper and the capacity of the capacitor bank is 22.6 nF. This experiment designed and mounted a repetitive triggering system to save the operator time making hundreds of shots. This emission amount is good for calibration and geometrical adjustment of an optical crystal x-ray focusing spectrometer.

  16. Development of a microfocus x-ray tube with multiple excitation sources

    Science.gov (United States)

    Maeo, Shuji; Krämer, Markus; Taniguchi, Kazuo

    2009-03-01

    A microfocus x-ray tube with multiple targets and an electron gun with a focal spot size of 10 μm in diameter has been developed. The electron gun contains a LaB6 cathode and an Einzel lens. The x-ray tube can be operated at 50 W (50 kV, 1 mA) and has three targets, namely, Cr, W, and Rh on the anode that can be selected completely by moving the anode position. A focal spot size of 10 μm in diameter can be achieved at 0.5 mA current. As demonstration of the usability of a multiexcitation x-ray tube, the fluorescence x-rays have been measured using a powder specimen mixed of TiO2, Co, and Zr of the same quantity. The differences of excitation efficiency have clearly appeared according to the change in excitation source. From the results discussed here, it can be expected that the presented x-ray tube will be a powerful tool in microx-ray fluorescence spectrometers and various x-ray instruments.

  17. Quantitative X-Ray Phase-Contrast Microtomography from a Compact Laser Driven Betatron Source

    CERN Document Server

    Wenz, J; Khrennikov, K; Bech, M; Thibault, P; Heigoldt, M; Pfeiffer, F; Karsch, S

    2014-01-01

    X-ray phase-contrast imaging has recently led to a revolution in resolving power and tissue contrast in biomedical imaging, microscopy and materials science. The necessary high spatial coherence is currently provided by either large-scale synchrotron facilities with limited beamtime access or by microfocus X-ray tubes with rather limited flux. X-rays radiated by relativistic electrons driven by well-controlled high-power lasers offer a promising route to a proliferation of this powerful imaging technology. A laser-driven plasma wave accelerates and wiggles electrons, giving rise to brilliant keV X-ray emission. This so-called Betatron radiation is emitted in a collimated beam with excellent spatial coherence and remarkable spectral stability. Here we present the first phase-contrast micro-tomogram revealing quantitative electron density values of a biological sample using betatron X-rays, and a comprehensive source characterization. Our results suggest that laser-based X-ray technology offers the potential fo...

  18. A POPULATION OF ULTRALUMINOUS X-RAY SOURCES WITH AN ACCRETING NEUTRON STAR

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Yong; Li, Xiang-Dong, E-mail: lixd@nju.edu.cn [Department of Astronomy, Nanjing University, Nanjing 210046 (China)

    2015-04-01

    Most ultraluminous X-ray sources (ULXs) are believed to be X-ray binary systems, but previous observational and theoretical studies tend to prefer a black hole rather than a neutron star (NS) accretor. The recent discovery of 1.37 s pulsations from the ULX M82 X-2 has established its nature as a magnetized NS. In this work we model the formation history of NS ULXs in an M82- or Milky Way (MW)-like Galaxy, by use of both binary population synthesis and detailed binary evolution calculations. We find that the birth rate is around 10{sup −4} yr{sup −1} for the incipient X-ray binaries in both cases. We demonstrate the distribution of the ULX population in the donor mass–orbital period plane. Our results suggest that, compared with black hole X-ray binaries, NS X-ray binaries may significantly contribute to the ULX population, and high-mass and intermediate-mass X-ray binaries dominate the NS ULX population in M82- and MW-like Galaxies, respectively.

  19. Groups of Galaxies in AEGIS: The 200 ksec Chandra Extended X-ray Source catalogue

    CERN Document Server

    Jeltema, Tesla E; Laird, Elise S; Willmer, Christopher N A; Coil, Alison L; Cooper, Michael C; Davis, Marc; Nandra, Kirpal; Newman, Jeffrey A

    2009-01-01

    We present the discovery of seven X-ray emitting groups of galaxies selected as extended X-ray sources in the 200 ksec Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). In addition, we report on AGN activity associated to these systems. Using the DEEP2 Galaxy Redshift Survey coverage, we identify optical counterparts and determine velocity dispersions. In particular, we find three massive high-redshift groups at z>0.7, one of which is at z=1.13, the first X-ray detections of spectroscopically selected DEEP2 groups. We also present a first look at the the L_X-T, L_X-sigma, and sigma-T scaling relations for high-redshift massive groups. We find that the properties of these X-ray selected systems agree well with the scaling relations of similar systems at low redshift, although there are X-ray undetected groups in the DEEP2 catalogue with similar velocity dispersions. The other three X-ray groups with identified redshifts are associated with lower mass groups at z~0.07 and...

  20. X-ray emissions by inner-shell ionization in laser-cluster interaction

    Science.gov (United States)

    Kishimoto, Y.; Nishiyama, H.; Masaki, T.; Moribayashi, K.; Fukuda, Y.; Li, J. Q.

    2006-10-01

    The dynamics of clusters irradiated by high intensity laser pulse has been interested due to its unique nature of the interaction different from other conventional targets and various applications have been proposed [1]. Specifically, an enhanced electric field that is more than one order of magnitude greater than the applied laser field is found to be produced due to the polarization effect near cluster surface. Generation of anomalously high charge state ions and associated short pulse X-rays were observed [2]. Based on simulation studies utilizing our particle code including atomic and relaxation processes [3] incorporated with a perturbation analyses of inner-shell ionization, we have investigated the properties of X-rays from F,O,N,C,B,Be,Li-like argon ions. With an increase of laser intensity, the X-ray pulse length becomes short, comparable to the order of incident laser pulse. [1] Y. Kishimoto et al., Phys. Plasmas 9, 589 (2002) [2] Y. Fukuda et al., Laer and Particle Beams 22, 215 (2004) [3] Y. Fukuda et al., Phys. Rev. A 73, 031201(R) (2006)

  1. Solving X-ray protein structures without a crystal: using X-ray Free Electron Laser, the fourth generation synchrotron light sources

    Institute of Scientific and Technical Information of China (English)

    Bo Huang

    2010-01-01

    @@ A synchrotron light source is a source of electromagnetic radiation artificially produced by specialized electron accelerators. Compared to the commonly used in-house X-ray sources, it is wavelength adjustable, much stronger and more focused. In the last two decades, synchrotron usage has become the mainstream for X-ray protein structure determination. Taking the advantage of micro-focus light beams of the third generation synchrotron, the size of a usable protein crystal for data collection decreases to micron level, which increases the rate of macromolecular structure determination to about 10 new protein data bank entries per day.

  2. Microfocus x-ray imaging of traceable pointlike {sup 22}Na sources for quality control

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, T.; Oda, K.; Sato, Y.; Ito, H.; Masuda, S.; Yamada, T.; Matsumoto, M.; Murayama, H.; Takei, H. [Allied Health Sciences, Kitasato University Kitasato 1-15-1, Minami-ku, Sagamihara-shi, Kanagawa 252-0373 (Japan); Positron Medical Center, Tokyo Metropolitan Institute of Gerontology Sakaecho 35-2, Itabashi-ku, Tokyo 173-0015 (Japan); Advanced Industrial Science and Technology (AIST) Central 2, Umezono 1-1-1, Tsukuba-shi, Ibaraki 305-8568 (Japan); Kanagawa Industrial Technology Center (KITC) Shimoimazumi 705-1, Ebina-shi, Kanagawa 243-0435 (Japan); Japan Radioisotope Association (JRIA) Komagome 2-28-45, Bunkyo-ku, Tokyo 113-8941 (Japan); Molecular Imaging Center, National Institute of Radiological Sciences Anagawa 4-9-1, Inage, Chiba 263-8555 (Japan); Graduate School of Medical Sciences, Kitasato University Kitasato 1-15-1, Minami-ku, Sagamihara-shi, Kanagawa 252-0373 (Japan)

    2012-07-15

    Purpose: The purpose of this study is to propose a microfocus x-ray imaging technique for observing the internal structure of small radioactive sources and evaluating geometrical errors quantitatively, and to apply this technique to traceable pointlike {sup 22}Na sources, which were designed for positron emission tomography calibration, for the purpose of quality control of the pointlike sources. Methods: A microfocus x-ray imaging system with a focus size of 0.001 mm was used to obtain projection x-ray images and x-ray CT images of five pointlike source samples, which were manufactured during 2009-2012. The obtained projection and tomographic images were used to observe the internal structure and evaluate geometrical errors quantitatively. Monte Carlo simulation was used to evaluate the effect of possible geometrical errors on the intensity and uniformity of 0.511 MeV annihilation photon pairs emitted from the sources. Results: Geometrical errors were evaluated with sufficient precision using projection x-ray images. CT images were used for observing the internal structure intuitively. As a result, four of the five examined samples were within the tolerance to maintain the total uncertainty below {+-}0.5%, given the source radioactivity; however, one sample was found to be defective. Conclusions: This quality control procedure is crucial and offers an important basis for using the pointlike {sup 22}Na source as a basic calibration tool. The microfocus x-ray imaging approach is a promising technique for visual and quantitative evaluation of the internal geometry of small radioactive sources.

  3. Ultrafast X-ray Science at the Sub-Picosecond Pulse Source

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Kelly J.; /SLAC, SSRL

    2005-09-30

    The ultrafast, high brightness x-ray free electron laser (XFEL) sources of the future have the potential to revolutionize the study of time dependent phenomena in the natural sciences. These linear accelerator (linac) sources will generate femtosecond (fs) x-ray pulses with peak flux comparable to conventional lasers, and far exceeding all other x-ray sources. The Stanford Linear Accelerator Center (SLAC) has pioneered the development of linac science and technology for decades, and since 2000 SLAC and the Stanford Synchrotron Radiation Laboratory (SSRL) have focused on the development of linac based ultrafast electron and x-ray sources. This development effort has led to the creation of a new x-ray source, called the Sub-Picosecond Pulse Source (SPPS), which became operational in 2003 [1]. The SPPS represents the first step toward the world's first hard x-ray free electron laser (XFEL), the Linac Coherent Light Source (LCLS), due to begin operation at SLAC in 2009. The SPPS relies on the same linac-based acceleration and electron bunch compression schemes that will be used at the LCLS to generate ultrashort, ultrahigh peak brightness electron bunches [2]. This involves creating an energy chirp on the electron bunch during acceleration and subsequent compression of the bunch in a series of energy-dispersive magnetic chicanes to create 80 fs electron pulses. The SPPS has provided an excellent opportunity to demonstrate the viability of these electron bunch compression schemes and to pursue goals relevant to the utilization and validation of XFEL light sources.

  4. Tunable, all-optical quasi-monochromatic Thomson X-ray source

    CERN Document Server

    Khrennikov, K; Buck, A; Xu, J; Heigoldt, M; Veisz, L; Karsch, S

    2014-01-01

    Brilliant X-ray sources are of great interest for many research fields from biology via medicine to material research. The quest for a cost-effective, brilliant source with unprecedented temporal resolution has led to the recent realization of various high-intensity-laser-driven X-ray beam sources. Here we demonstrate the first all-laser-driven, energy-tunable and quasi-monochromatic X-ray source based on Thomson backscattering. This is a decisive step beyond previous results, where the emitted radiation exhibited an uncontrolled broad energy distribution. In the experiment, one part of the laser beam was used to drive a few-fs bunch of quasi-monoenergetic electrons from a Laser-Wakefield Accelerator (LWFA), while the remainder was scattered off the bunch in a near-counter-propagating geometry. When the electron energy was tuned from 10-50 MeV, narrow-bandwidth X-ray spectra peaking at 5-35keV were directly measured, limited in photon energy by the sensitivity curve of our X-ray detector. Due to the ultrashor...

  5. A Bright Spatially-Coherent Compact X-ray Synchrotron Source

    CERN Document Server

    Kneip, S; Martins, J L; Martins, S F; Bellei, C; Chvykov, V; Dollar, F; Fonseca, R; Huntington, C; Kalintchenko, G; Maksimchuk, A; Mangles, S P D; Matsuoka, T; Nagel, S R; Palmer, C; Schreiber, J; Phuoc, K Ta; Thomas, A G R; Yanovsky, V; Silva, L O; Krushelnick, K; Najmudin, Z

    2009-01-01

    Each successive generation of x-ray machines has opened up new frontiers in science, such as the first radiographs and the determination of the structure of DNA. State-of-the-art x-ray sources can now produce coherent high brightness keV x-rays and promise a new revolution in imaging complex systems on nanometre and femtosecond scales. Despite the demand, only a few dedicated synchrotron facilities exist worldwide, partially due the size and cost of conventional (accelerator) technology. Here we demonstrate the use of a recently developed compact laser-plasma accelerator to produce a well-collimated, spatially-coherent, intrinsically ultrafast source of hard x-rays. This method reduces the size of the synchrotron source from the tens of metres to centimetre scale, accelerating and wiggling a high electron charge simultaneously. This leads to a narrow-energy spread electron beam and x-ray source that is >1000 times brighter than previously reported plasma wiggler and thus has the potential to facilitate a myri...

  6. Discovery of Extremely Embedded X-ray Sources in the R Coronae Australis Star Forming Core

    CERN Document Server

    Hamaguchi, K; Petre, R; White, N E; Stelzer, B; Nedachi, K; Kobayashi, N; Tokunaga, A T; Hamaguchi, Kenji; Corcoran, Michael F.; Petre, Rob; White, Nicholas E.; Stelzer, Beate; Nedachi, Ko; Kobayashi, Naoto; Tokunaga, Alan T.

    2005-01-01

    With the XMM-Newton and Chandra observatories, we detected two extremely embedded X-ray sources in the R Corona Australis (R CrA) star forming core, near IRS 7. These sources, designated as XB and XA, have X-ray absorption columns of ~3e23 cm-2 equivalent to AV ~180 mag. They are associated with the VLA centimeter radio sources 10E and 10W, respectively. XA is the counterpart of the near-infrared source IRS 7, whereas XB has no K-band counterpart above 19.4 mag. This indicates that XB is younger than typical Class I protostars, probably a Class 0 protostar or in an intermediate phase between Class 0 and Class I. The X-ray luminosity of XB varied between 29X-ray brightness by a factor of two in 30 ksec during an XMM-Newton observation. The XMM-Newton spectra indicate emission from a hot plasma with kT ~3-4 keV and also show fluorescent emission from cold iron. Though the X-ray spectrum from XB is similar to flare ...

  7. SPIDERS: the spectroscopic follow-up of X-ray selected clusters of galaxies in SDSS-IV

    CERN Document Server

    Clerc, Nicolas; Zhang, Yu-Ying; Finoguenov, Alexis; Dwelly, Tom; Nandra, Kirpal; Collins, Chris A; Dawson, Kyle; Kneib, Jean-Paul; Rozo, Eduardo; Rykoff, Eli; Sadibekova, Tatyana; Brownstein, Joel R; Lin, Yen-Ting; Ridl, Jethro; Salvato, Mara; Schwope, Axel; Steinmetz, Matthias; Seo, Hee-Jong; Tinker, Jeremy

    2016-01-01

    SPIDERS (The SPectroscopic IDentification of eROSITA Sources) is a program dedicated to the homogeneous and complete spectroscopic follow-up of X-ray AGN and galaxy clusters over a large area ($\\sim$7500 deg$^2$) of the extragalactic sky. SPIDERS is part of the SDSS-IV project, together with the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) and the Time-Domain Spectroscopic Survey (TDSS). This paper describes the largest project within SPIDERS before the launch of eROSITA: an optical spectroscopic survey of X-ray selected, massive ($\\sim 10^{14}$ to $10^{15}~M_{\\odot}$) galaxy clusters discovered in ROSAT and XMM-Newton imaging. The immediate aim is to determine precise ($\\Delta_z \\sim 0.001$) redshifts for 4,000-5,000 of these systems out to $z \\sim 0.6$. The scientific goal of the program is precision cosmology, using clusters as probes of large-scale structure in the expanding Universe. We present the cluster samples, target selection algorithms and observation strategies. We demonstrate the eff...

  8. Upper Limit on Dimming of Cosmological Sources by Intergalactic Grey Dust from the Soft X-ray Background

    CERN Document Server

    Dijkstra, Mark

    2009-01-01

    Active Galactic Nuclei (AGN) produce a dominant fraction (~80%) of the Soft X-ray background (SXB) at photon energies 0.5X-ray halos around AGN. Taking account of known galaxies and galaxy clusters, only a fraction F_halo <10% of the SXB can be in the form of diffuse X-ray halos around AGN. We therefore limit the intergalactic opacity to optical/infrared photons from large dust grains (with radii in the range a=0.2-2.0 mum) to a level tau_GD<0.15(F_halo/10%) to a redshift z~1. Our results are only weakly dependent on the grain size distribution or the redshift evolution of the intergalactic dust. Stacking X-ray images of AGN can be used to improve our constraints and diminish the importance of dust as a source of systematic uncertainty for future supernova surveys which aim to improve the precision on measuring the redshift evolution of the dark energy equation-of-state.

  9. MAXI/GSC detection of X-ray enhancement toward the globular cluster Tarzan 1

    Science.gov (United States)

    Negoro, H.; Shidatsu, M.; Ueno, S.; Tomida, H.; Nakahira, S.; Kimura, M.; Ishikawa, M.; Nakagawa, Y.; Mihara, T.; Sugizaki, M.; Serino, M.; Morii, M.; Yamamoto, T.; Sugimoto, J.; Takagi, T.; Matsuoka, M.; Kawai, N.; Usui, R.; Ishikawa, K.; Yoshii, T.; Yoshida, A.; Sakamoto, T.; Nakano, Y.; Kawakubo, Y.; Tsunemi, H.; Sasaki, M.; Nakajima, M.; Fukushima, K.; Onodera, T.; Suzuki, K.; Ueda, Y.; Kawamuro, T.; Tsuboi, Y.; Higa, M.; Yamauchi, M.; Yoshidome, K.; Ogawa, Y.; Yamada, H.; Yamaoka, K.

    2013-06-01

    At 23:18 UT on May 24th, 2013, the MAXI/GSC auto-detection system triggered X-ray enhancement at the position consistent with the globular cluster Terzan 1. We have confirmed that the X-ray flux has gradually increased from around May 19th, 2013 (MJD 56431), and still remains stable on timescale of days at the 4-10 keV flux of about 8 mCrab. The central position of the enhanced region in the smoothed 2-20 keV image, obtained from May 19th to May 30th, is (R.A., Dec) = (263.84, -30.48) with a typical uncertainty of 0.3 deg.

  10. X-Ray Localization of the Intermediate-Mass Black Hole in the Globular Cluster G1 with Chandra

    CERN Document Server

    Kong, A K H; Di Stefano, R; Barmby, P; Lewin, W H G; Primini, F A

    2009-01-01

    We report the most accurate X-ray position of the giant globular cluster G1 in M31 by using the Chandra X-ray Observatory, Hubble Space Telescope (HST), and Canada-France-Hawaii Telescope (CFHT). G1 is clearly detected with Chandra and by cross-registering with HST and CFHT images, we derive a 1sigma error radius of 0.15", significantly smaller than the previous measurement by XMM-Newton. We conclude that the X-ray emission of G1 comes from within the core radius of the cluster. There are two possibilities for the origin of the X-ray emission: it could be due to either accretion of a central intermediate-mass black hole, or ordinary low-mass X-ray binaries. Based on the ratio of X-ray to the Eddington luminosity, an intermediate-mass black hole accreting from the cluster gas seems unlikely and we suggest that the X-rays are due to accretion from a companion. We also find that the X-ray emission may be offset from the radio emission. Future high-resolution and high-sensitivity radio imaging observations will r...

  11. Insights into the location and dynamics of the coolest X-ray emitting gas in clusters of galaxies

    CERN Document Server

    Pinto, Ciro; Ogorzalek, Anna; Zhuravleva, Irina; Werner, Norbert; Sanders, Jeremy; Zhang, Yu-Ying; Gu, Liyi; de Plaa, Jelle; Ahoranta, Jussi; Finoguenov, Alexis; Johnstone, Roderick; Canning, Rebecca E A

    2016-01-01

    We extend our previous study of the cool gas responsible for the emission of OVII X-ray lines in the cores of clusters and groups of galaxies. This is the coolest X-ray emitting phase and connects the 10,000 K H {\\alpha} emitting gas to the million degree phase, providing a useful tool to understand cooling in these objects. We study the location of the O VII gas and its connection to the intermediate Fe XVII and hotter O VIII phases. We use high-resolution X-ray grating spectra of elliptical galaxies with strong Fe XVII line emission and detect O VII in 11 of 24 objects. Comparing the O VII detection level and resonant scattering, which is sensitive to turbulence and temperature, suggests that OVII is preferably found in cooler objects, where the FeXVII resonant line is suppressed due to resonant scattering, indicating subsonic turbulence. Although a larger sample of sources and further observations is needed to distinguish between effects from temperature and turbulence, our results are consistent with cool...

  12. Large-scale Nanostructure Simulations from X-ray Scattering Data On Graphics Processor Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Sarje, Abhinav; Pien, Jack; Li, Xiaoye; Chan, Elaine; Chourou, Slim; Hexemer, Alexander; Scholz, Arthur; Kramer, Edward

    2012-01-15

    X-ray scattering is a valuable tool for measuring the structural properties of materialsused in the design and fabrication of energy-relevant nanodevices (e.g., photovoltaic, energy storage, battery, fuel, and carbon capture andsequestration devices) that are key to the reduction of carbon emissions. Although today's ultra-fast X-ray scattering detectors can provide tremendousinformation on the structural properties of materials, a primary challenge remains in the analyses of the resulting data. We are developing novelhigh-performance computing algorithms, codes, and software tools for the analyses of X-ray scattering data. In this paper we describe two such HPCalgorithm advances. Firstly, we have implemented a flexible and highly efficient Grazing Incidence Small Angle Scattering (GISAXS) simulation code based on theDistorted Wave Born Approximation (DWBA) theory with C++/CUDA/MPI on a cluster of GPUs. Our code can compute the scattered light intensity from any givensample in all directions of space; thus allowing full construction of the GISAXS pattern. Preliminary tests on a single GPU show speedups over 125x compared tothe sequential code, and almost linear speedup when executing across a GPU cluster with 42 nodes, resulting in an additional 40x speedup compared to usingone GPU node. Secondly, for the structural fitting problems in inverse modeling, we have implemented a Reverse Monte Carlo simulation algorithm with C++/CUDAusing one GPU. Since there are large numbers of parameters for fitting in the in X-ray scattering simulation model, the earlier single CPU code required weeks ofruntime. Deploying the AccelerEyes Jacket/Matlab wrapper to use GPU gave around 100x speedup over the pure CPU code. Our further C++/CUDA optimization deliveredan additional 9x speedup.

  13. A New Method to Quantify X-ray Substructures in Clusters of Galaxies

    CERN Document Server

    Andrade-Santos, Felipe; Laganá, Tatiana Ferraz

    2011-01-01

    We present a new method to quantify substructures in clusters of galaxies, based on the analysis of the intensity of structures. This analysis is done in a residual image that is the result of the subtraction of a surface brightness model, obtained by fitting a two-dimensional analytical model (beta-model or S\\'ersic profile) with elliptical symmetry, from the X-ray image. Our method is applied to 34 clusters observed by the Chandra Space Telescope that are in the redshift range 0.02X-ray luminosity, temperature, and cluster redshift. We use our method to separate the clusters in two sub-samples of high and low substructure levels. We conclude, using Monte Carlo simulations, that the method recuperates very well the true amount of substructure for small angular core radii clusters (with respect to the whole image s...

  14. On the origin of two unidentified radio/X-ray sources discovered with XMM-Newton

    Science.gov (United States)

    García, Federico; Combi, Jorge A.; Medina, María C.; Romero, Gustavo E.

    2015-12-01

    Aims: We aim at clarifying the nature of the emission of two spatially related unidentified X-ray sources detected with XMM-Newton telescope at intermediate-low Galactic latitude Methods: We use the imaging and spectral capabilities of XMM-Newton to study the X-ray properties of these two sources. In addition, we complement our study with radio data obtained at different frequencies to analyze a possible physical association between the sources. Results: Observations reveal a point-like source aligned with elongated diffuse emission. The X-ray spectra of these sources is best-fitted by an absorbed power law with photon index Γ ~ 1.7 for the point-like source and ~2.0 for the extended source. Both sources show nonthermal radio-continuum counterparts that might indicate a physical association. In addition, from the available data, we did not detect variability on the point-like source in several timescales. Two possible scenarios are analyzed: one Galactic and one extra-Galactic. First, based on HI line absorption, assuming a Galactic origin, we infer a distance upper bound of ≲2 kpc, which poses a constraint on the height over the Galactic plane of ≲200 pc and on the linear size of the system of ≲2.3 pc. In this case, the X-ray luminosities are ≳1032 erg s-1 and ≳7.5 × 1032 erg s-1, for the point-like and extended sources, respectively. Second, an extra-Galactic nature is discussed, where the point-like source might be the core of a radio galaxy and the extended source its lobe. In this case, we compare derived fluxes, spectral indices, and spatial correlation with those typical from the radio galaxy population, showing the feasibility of this alternative astrophysical scenario. Conclusions: From the available observational evidence, we suggest that the most promising scenario to explain the nature of these sources is a system consisting of a one-sided radio galaxy, where the point-like source is an active galactic nucleus and the extended source

  15. The Antennae Ultraluminous X-Ray Source, X-37, Is A Background Quasar

    CERN Document Server

    Clark, D M; Eikenberry, S S; Brandl, B R; Wilson, J C; Carson, J C; Henderson, C P; Hayward, T L; Barry, J; Ptak, A F; Colbert, E J M

    2005-01-01

    In this paper we report that a bright, X-ray source in the Antennae galaxies (NGC 4038/9), previously identified as an ultra-luminous X-ray source, is in fact a background quasar. We identify an isolated infrared and optical counterpart within 0.3+/-0.5 arcseconds the X-ray source X-37. After acquiring an optical spectrum of its counterpart, we use the narrow [OIII] and broad H_alpha emission lines to identify X-37 as a quasar at a redshift of z=0.26. Through a U, V, and K_s photometric analysis, we demonstrate that most of the observable light along this line of sight is from the quasar. We discuss the implications of this discovery and the importance of acquiring spectra for optical and IR counterparts to ULXs.

  16. The X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Alonso-Mori, Roberto; Caronna, Chiara; Chollet, Matthieu; Curtis, Robin; Damiani, Daniel S.; Defever, Jim; Feng, Yiping; Flath, Daniel L.; Glownia, James M. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Lee, Sooheyong [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Hasylab at DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Lemke, Henrik T.; Nelson, Silke; Bong, Eric; Sikorski, Marcin; Song, Sanghoon; Srinivasan, Venkat; Stefanescu, Daniel; Zhu, Diling; Robert, Aymeric, E-mail: aymeric@slac.stanford.edu [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2015-04-14

    A description of the X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source is presented. Recent highlights illustrate the coherence properties of the source as well as some recent dynamics measurements and future directions. The X-ray Correlation Spectroscopy instrument is dedicated to the study of dynamics in condensed matter systems using the unique coherence properties of free-electron lasers. It covers a photon energy range of 4–25 keV. The intrinsic temporal characteristics of the Linac Coherent Light Source, in particular the 120 Hz repetition rate, allow for the investigation of slow dynamics (milliseconds) by means of X-ray photon correlation spectroscopy. Double-pulse schemes could probe dynamics on the picosecond timescale. A description of the instrument capabilities and recent achievements is presented.

  17. Generating Picosecond X-Ray Pulses with Beam Manipulation in Synchrotron Light Sources

    CERN Document Server

    Guo, Weiming; Harkay, Katherine C; Sajaev, Vadim; Yang Bing Xin

    2005-01-01

    The length of x-ray pulses generated by storage ring light sources is usually tens of picoseconds. For example, the value is 40 ps rms at the Advanced Photon Source (APS). Methods of x-ray pulse compression are of great interest at the APS. One possible method, per Zholents et al., is to tilt the electron bunch with deflecting rf cavities.* Alternately, we found that the electron bunch can develop a tilt after application of a vertical kick in the presence of nonzero chromaticity. After slicing, the x-ray pulse length is determined by the tilt angle and the vertical beam size. In principal, sub-picosecond pulses can be obtained at APS. To date we have observed 6 ps rms visible light pulses with a streak camera. Efforts are underway to attempt further compression of the x-ray pulse and to increase the brilliance. This method can be easily applied to any storage ring light sources to generate x-ray pulses up to two orders of magnitude shorter than the electron bunch length. In this paper, we will present the th...

  18. Plasma diagnostics of the SIMPA Ecr ion source by X-ray spectroscopy, Collisions of H-like Neon ions with Argon clusters; Diagnostic du plasma de la source d'ions ECR SIMPA par spectroscopie X, Collision d'ions neon hydrogenoides avec des agregats d'argon

    Energy Technology Data Exchange (ETDEWEB)

    Adrouche, N

    2006-09-15

    The first part of this thesis is devoted to the SIMPA ECR ion source characterization, first, I explored the ion source's capacities on the point of view of extracted currents for three elements, argon, krypton and neon. By analyzing the Bremsstrahlung spectra, I determined the electronic temperature in the plasma and the electronic and ionic densities. In a second time, I recorded high resolution X-spectra of argon and krypton plasma's. By taking into account the principal mechanisms of production of a K hole in the ions inside the plasma, I determined the ionic densities of the high charge states of argon. Lastly, I highlighted a correlation between the ions charge states densities with the intensities of extracted currents. The second part of the thesis is devoted to Ne{sup 9+-} argon clusters collisions. First, I presented simple and effective theoretical models allowing to describe the phenomena occurring during a collision, from the point of view of the projectile. I carried out a simulation for a collision of an ion Ne{sup 9+} with an argon cluster of a given size, which has enabled us to know the energy levels populated during the electronic capture and to follow the number of electrons in each projectile shell. Lastly, I presented the first results of a collision between a Ne{sup 9+} beam and argon clusters. These results, have enabled me by using projectile X-ray spectroscopy during the ions-clusters collision, to evidence a strong clustering of targets atoms and to highlight an electronic multi-capture in the projectile ion excited states. (author)

  19. Flat Field Anomalies in an X-ray CCD Camera Measured Using a Manson X-ray Source (HTPD 08 paper)

    Energy Technology Data Exchange (ETDEWEB)

    Haugh, M; Schneider, M B

    2008-04-28

    The Static X-ray Imager (SXI) is a diagnostic used at the National Ignition Facility (NIF) to measure the position of the X-rays produced by lasers hitting a gold foil target. The intensity distribution taken by the SXI camera during a NIF shot is used to determine how accurately NIF can aim laser beams. This is critical to proper NIF operation. Imagers are located at the top and the bottom of the NIF target chamber. The CCD chip is an X-ray sensitive silicon sensor, with a large format array (2k x 2k), 24 {micro}m square pixels, and 15 {micro}m thick. A multi-anode Manson X-ray source, operating up to 10kV and 10W, was used to characterize and calibrate the imagers. The output beam is heavily filtered to narrow the spectral beam width, giving a typical resolution E/{Delta}E {approx} 10. The X-ray beam intensity was measured using an absolute photodiode that has accuracy better than 1% up to the Si K edge and better than 5% at higher energies. The X-ray beam provides full CCD illumination and is flat, within {+-}1% maximum to minimum. The spectral efficiency was measured at 10 energy bands ranging from 930 eV to 8470 eV. We observed an energy dependent pixel sensitivity variation that showed continuous change over a large portion of the CCD. The maximum sensitivity variation occurred at 8470 eV. The geometric pattern did not change at lower energies, but the maximum contrast decreased and was not observable below 4 keV. We were also able to observe debris, damage, and surface defects on the CCD chip. The Manson source is a powerful tool for characterizing the imaging errors of an X-ray CCD imager. These errors are quite different from those found in a visible CCD imager.

  20. Chandra Observations of the X-ray Point Source Population in NGC 4636

    CERN Document Server

    Posson-Brown, J; Forman, W; Donnelly, R H; Jones, C; Posson-Brown, Jennifer; Raychaudhury, Somak; Forman, William; Jones, Christine

    2006-01-01

    We present an analysis of the X-ray point source population in the nearby Virgo elliptical galaxy NGC 4636 from four Chandra X-ray observations. These ACIS observations, totaling ~210 ks, were taken over a three year period. Using a wavelet decomposition detection algorithm, we detect 336 individual point sources. For our analysis, we use a subset of the 245 detections with >10 cts (a limiting luminosity of approximately 1E37 erg/s in the 0.5-2 keV band, outside the 1.5' bright galaxy core). Of these sources, ~120 are likely members of the galaxy. We examine, for the first time, variability over a period of years for X-ray point sources in an elliptical galaxy. We present a luminosity function for the point sources in NGC 4636, fit by a power-law with gamma= -1.24 +/- 0.04, as well as a radial source density profile, hardness ratios for the sources, and lightcurves for bright sources which display short-term variability. We find an upper limit to the current X-ray luminosity of the historical supernova SN1939...