WorldWideScience

Sample records for chandra x-ray sources

  1. 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

  2. Chandra Discovers X-ray Source at the Center of Our Galaxy

    Science.gov (United States)

    2000-01-01

    Culminating 25 years of searching by astronomers, researchers at Massachusetts Institute of Technology say that a faint X-ray source, newly detected by NASA's Chandra X-ray Observatory, may be the long-sought X-ray emission from a known supermassive black hole at the center of our galaxy. Frederick K. Baganoff and colleagues from Pennsylvania State University, University Park, and the University of California, Los Angeles, will present their findings today in Atlanta at the 195th national meeting of the American Astronomical Society. Baganoff, lead scientist for the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer (ACIS) team's "Sagittarius A* and the Galactic Center" project and postdoctoral research associate at MIT, said that the precise positional coincidence between the new X-ray source and the radio position of a long-known source called Sagittarius A* "encourages us to believe that the two are the same." Sagittarius A* is a point-like, variable radio source at the center of our galaxy. It looks like a faint quasar and is believed to be powered by gaseous matter falling into a supermassive black hole with 2.6 million times the mass of our Sun. Chandra's remarkable detection of this X-ray source has placed astronomers within a couple of years of a coveted prize: measuring the spectrum of energy produced by Sagittarius A* to determine in detail how the supermassive black hole that powers it works. "The race to be the first to detect X-rays from Sagittarius A* is one of the hottest and longest-running in all of X-ray astronomy," Baganoff said. "Theorists are eager to hear the results of our observation so they can test their ideas." But now that an X-ray source close to Sagittarius A* has been found, it has taken researchers by surprise by being much fainter than expected. "There must be something unusual about the environment around this black hole that affects how it is fed and how the gravitational energy released from the infalling matter is

  3. CHANDRA ACIS SURVEY OF X-RAY POINT SOURCES: THE SOURCE CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song; Liu, Jifeng; Qiu, Yanli; Bai, Yu; Yang, Huiqin; Guo, Jincheng; Zhang, Peng, E-mail: jfliu@bao.ac.cn, E-mail: songw@bao.ac.cn [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    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 {sub 25} isophotes of 1110 galaxies, and 7504 sources are located between the D {sub 25} and 2 D {sub 25} isophotes of 910 galaxies. Contamination analysis with the log N –log S relation indicates that 51.3% of objects within 2 D {sub 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 10{sup 37}, 10{sup 38}, and 10{sup 39} erg s{sup −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 {sub 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

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

    Science.gov (United States)

    Clark, D. M.; Eikenberry, S. S.; 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.

    2007-03-01

    We use deep J (1.25 μm) and Ks (2.15 μm) images of the Antennae (NGC 4038/4039) obtained with the Wide-field InfraRed Camera on the Palomar 200 inch (5 m) telescope, together with the Chandra X-ray source list of Zezas and coworkers to search for infrared 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 99.9% confidence level that IR counterparts to X-ray sources are ΔMKs~1.2 mag more luminous than average non-X-ray clusters. We also note that the X-ray/IR matches are concentrated in the spiral arms and ``overlap'' regions of the Antennae. This implies that these X-ray sources lie in the most ``super'' of the Antennae's super star clusters, and thus trace the recent massive star formation history here. Based on the NH inferred from the X-ray sources without IR counterparts, we determine that the absence of most of the ``missing'' IR counterparts is not due to extinction, but that these sources are intrinsically less luminous in the IR, implying that they trace a different (possibly older) stellar population. We find no clear correlation between X-ray luminosity classes and IR properties of the sources, although small-number statistics hamper this analysis.

  5. 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.

  6. Chandra Finds X-ray Star Bonanza in the Orion Nebula

    Science.gov (United States)

    2000-01-01

    NASA's Chandra X-ray Observatory has resolved nearly a thousand faint X-ray-emitting stars in a single observation of young stars in the Orion Nebula. The discovery--the richest field of X-ray sources ever obtained in the history of X-ray astronomy--will be presented on Friday, January 14, at the 195th national meeting of the American Astronomical Society in Atlanta, Georgia. The Orion region is a dense congregation of about 2,000 very young stars formed during the past few million years. The discovery of such a wealth of X-ray stars in the closest massive star-forming region to Earth (only 1,500 light years away) is expected to have a profound impact on our understanding of star formation and evolution. "We've detected X-rays from so many fantastic objects, such as very young massive stars and stars so small that they may evolve into brown dwarfs," said Gordon Garmire, Evan Pugh Professor at Penn State University, University Park. "Chandra's superb angular resolution has resolved this dense cluster of stars with arcsecond accuracy and unsurpassed sensitivity." Garmire leads the team using Chandra's ACIS detector, the Advanced CCD Imaging Spectrometer, conceived and developed for NASA by Penn State University and the Massachusetts Institute of Technology. The brilliant Orion region has awed humankind for millennia. The most massive and brightest of these nascent stars are in the Orion Trapezium, which illuminates the Orion Nebula, also known as Messier 42. The Trapezium and its luminous gas can be seen with the unaided eye in the winter sky in the "sword" of the Orion constellation. Young stars, such as those found in Orion, are known to be much brighter in X-rays than middle-aged stars such as the Sun. The elevated X-ray emission is thought to arise from violent flares in strong magnetic fields near the surfaces of young stars. The Sun itself was probably thousands of times brighter in X-rays during its first few million years. Although the enhanced magnetic

  7. Chandra-SDSS Normal and Star-Forming Galaxies. I. X-Ray Source Properties of Galaxies Detected by the Chandra X-Ray Observatory in SDSS DR2

    Science.gov (United States)

    Hornschemeier, A. E.; Heckman, T. M.; Ptak, A. F.; Tremonti, C. A.; Colbert, E. J. M.

    2005-01-01

    We have cross-correlated X-ray catalogs derived from archival Chandra X-Ray Observatory ACIS observations with a Sloan Digital Sky Survey Data Release 2 (DR2) galaxy catalog to form a sample of 42 serendipitously X-ray-detected galaxies over the redshift interval 0.03X-ray-studied samples of normal galaxies and those in the deepest X-ray surveys. Our chief purpose is to compare optical spectroscopic diagnostics of activity (both star formation and accretion) with X-ray properties of galaxies. Our work supports a normalization value of the X-ray-star formation rate correlation consistent with the lower values published in the literature. The difference is in the allocation of X-ray emission to high-mass X-ray binaries relative to other components, such as hot gas, low-mass X-ray binaries, and/or active galactic nuclei (AGNs). We are able to quantify a few pitfalls in the use of lower resolution, lower signal-to-noise ratio optical spectroscopy to identify X-ray sources (as has necessarily been employed for many X-ray surveys). Notably, we find a few AGNs that likely would have been misidentified as non-AGN sources in higher redshift studies. However, we do not find any X-ray-hard, highly X-ray-luminous galaxies lacking optical spectroscopic diagnostics of AGN activity. Such sources are members of the ``X-ray-bright, optically normal galaxy'' (XBONG) class of AGNs.

  8. CHANDRA ACIS SURVEY OF X-RAY POINT SOURCES IN NEARBY GALAXIES. II. X-RAY LUMINOSITY FUNCTIONS AND ULTRALUMINOUS X-RAY SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song; Qiu, Yanli; Liu, Jifeng [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Bregman, Joel N., E-mail: songw@bao.ac.cn, E-mail: jfliu@bao.ac.cn [University of Michigan, Ann Arbor, MI 48109 (United States)

    2016-09-20

    Based on the recently completed Chandra /ACIS survey of X-ray point sources in nearby galaxies, we study the X-ray luminosity functions (XLFs) for X-ray point sources in different types of galaxies and the statistical properties of ultraluminous X-ray sources (ULXs). Uniform procedures are developed to compute the detection threshold, to estimate the foreground/background contamination, and to calculate the XLFs for individual galaxies and groups of galaxies, resulting in an XLF library of 343 galaxies of different types. With the large number of surveyed galaxies, we have studied the XLFs and ULX properties across different host galaxy types, and confirm with good statistics that the XLF slope flattens from lenticular ( α ∼ 1.50 ± 0.07) to elliptical (∼1.21 ± 0.02), to spirals (∼0.80 ± 0.02), to peculiars (∼0.55 ± 0.30), and to irregulars (∼0.26 ± 0.10). The XLF break dividing the neutron star and black hole binaries is also confirmed, albeit at quite different break luminosities for different types of galaxies. A radial dependency is found for ellipticals, with a flatter XLF slope for sources located between D {sub 25} and 2 D {sub 25}, suggesting the XLF slopes in the outer region of early-type galaxies are dominated by low-mass X-ray binaries in globular clusters. This study shows that the ULX rate in early-type galaxies is 0.24 ± 0.05 ULXs per surveyed galaxy, on a 5 σ confidence level. The XLF for ULXs in late-type galaxies extends smoothly until it drops abruptly around 4 × 10{sup 40} erg s{sup −1}, and this break may suggest a mild boundary between the stellar black hole population possibly including 30 M {sub ⊙} black holes with super-Eddington radiation and intermediate mass black holes.

  9. Early Chandra X-ray Observations of Eta Carinae

    OpenAIRE

    Seward, F. D.; Butt, Y. M.; Karovska, M.; Schlegel, A. Prestwich. E. M.; Corcoran, M.

    2001-01-01

    Sub-arcsecond resolution Chandra observations of Eta Carinae reveal a 40 arcsec X 70 arcsec ring or partial shell of X-ray emission surrounding an unresolved, bright, central source. The spectrum of the central source is strongly absorbed and can be fit with a high-temperature thermal continuum and emission lines. The surrounding shell is well outside the optical/IR bipolar nebula and is coincident with the Outer Shell of Eta Carinae. The X-ray spectrum of the Shell is much softer than that o...

  10. CHANDRA X-RAY DETECTION OF THE ENIGMATIC FIELD STAR BP Psc

    International Nuclear Information System (INIS)

    Kastner, Joel H.; Montez, Rodolfo; Rodriguez, David; Zuckerman, B.; Perrin, Marshall D.; Grosso, Nicolas; Forveille, Thierry; Graham, James R.

    2010-01-01

    BP Psc is a remarkable emission-line field star that is orbited by a dusty disk and drives a parsec-scale system of jets. We report the detection by the Chandra X-ray Observatory of a weak X-ray point source coincident with the centroids of optical/IR and submillimeter continuum emission at BP Psc. As the star's photosphere is obscured throughout the visible and near-infrared, the Chandra X-ray source likely represents the first detection of BP Psc itself. The X-rays most likely originate with magnetic activity at BP Psc and hence can be attributed either to a stellar corona or to star-disk interactions. The log of the ratio of X-ray to bolometric luminosity, log(L X /L bol ), lies in the range -5.8 to -4.2. This is smaller than log(L X /L bol ) ratios typical of low-mass, pre-main sequence stars, but is well within the log(L X /L bol ) range observed for rapidly rotating (FK Com-type) G giant stars. Hence, the Chandra results favor an exotic model wherein the disk/jet system of BP Psc is the result of its very recently engulfing a companion star or a giant planet, as the primary star ascended the giant branch.

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

    Science.gov (United States)

    McDowell, Jonathan; CIAO Team

    2018-01-01

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

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

    Science.gov (United States)

    2001-03-01

    in three different wavebands. PR Photo 09b/01 : A VLT/FORS1 spectrum of a 'Type II Quasar' discovered during this programme. The 'Chandra Deep Field South' and the X-Ray Background ESO PR Photo 09a/01 ESO PR Photo 09a/01 [Preview - JPEG: 400 x 183 pix - 76k] [Normal - JPEG: 800 x 366 pix - 208k] [Hires - JPEG: 3000 x 1453 pix - 1.4M] Caption : PR Photo 09a/01 shows optical/infrared images in three wavebands ('Blue', 'Red', 'Infrared') from ESO telescopes of the Type II Quasar CXOCDFS J033229.9 -275106 (at the centre), one of the distant X-ray sources identified in the Chandra Deep Field South (CDFS) area during the present study. Technical information about these photos is available below. The 'Chandra Deep Field South (CDFS)' is a small sky area in the southern constellation Fornax (The Oven). It measures about 16 arcmin across, or roughly half the diameter of the full moon. There is unusually little gas and dust within the Milky Way in this direction and observations towards the distant Universe within this field thus profit from an particularly clear view. That is exactly why this sky area was selected by an international team of astronomers [1] to carry out an ultra-deep survey of X-ray sources with the orbiting Chandra X-Ray Observatory . In order to detect the faintest possible sources, NASA's satellite telescope looked in this direction during an unprecedented total of almost 1 million seconds of exposure time (11.5 days). The main scientific goal of this survey is to understand the nature and evolution of the elusive sources that make up the 'X-ray background' . This diffuse glare in the X-ray sky was discovered by Riccardo Giacconi and his collaborators during a pioneering rocket experiment in 1962. The excellent imaging quality of Chandra (the angular resolution is about 1 arcsec) makes it possible to do extremely deep exposures without encountering problems introduced by the "confusion effect". This refers to the overlapping of images of sources that are

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-09-20

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

  14. NASA Unveils First Images From Chandra X-Ray Observatory

    Science.gov (United States)

    1999-08-01

    Extraordinary first images from NASA's Chandra X-ray Observatory trace the aftermath of a gigantic stellar explosion in such stunning detail that scientists can see evidence of what may be a neutron star or black hole near the center. Another image shows a powerful X-ray jet blasting 200,000 light years into intergalactic space from a distant quasar. Released today, both images confirm that NASA's newest Great Observatory is in excellent health and its instruments and optics are performing up to expectations. Chandra, the world's largest and most sensitive X-ray telescope, is still in its orbital check-out and calibration phase. "When I saw the first image, I knew that the dream had been realized," said Dr. Martin Weisskopf, Chandra Project Scientist, NASA's Marshall Space Flight Center, Huntsville, AL. "This observatory is ready to take its place in the history of spectacular scientific achievements." "We were astounded by these images," said Harvey Tananbaum, Director of the Smithsonian Astrophysical Observatory's Chandra X- ray Center, Cambridge, MA. "We see the collision of the debris from the exploded star with the matter around it, we see shock waves rushing into interstellar space at millions of miles per hour, and, as a real bonus, we see for the first time a tantalizing bright point near the center of the remnant that could possibly be a collapsed star associated with the outburst." Chandra's PKS 0637-752 PKS 0637-752 After the telescope's sunshade door was opened last week, one of the first images taken was of the 320-year-old supernova remnant Cassiopeia A, which astronomers believe was produced by the explosion of a massive star. Material blasted into space from the explosion crashed into surrounding material at 10 million miles per hour. This collision caused violent shock waves, like massive sonic booms, creating a vast 50-million degree bubble of X-ray emitting gas. Heavy elements in the hot gas produce X-rays of specific energies. Chandra's ability

  15. The Chandra X-ray Observatory PSF Library

    Science.gov (United States)

    Karovska, M.; Beikman, S. J.; Elvis, M. S.; Flanagan, J. M.; Gaetz, T.; Glotfelty, K. J.; Jerius, D.; McDowell, J. C.; Rots, A. H.

    Pre-flight and on-orbit calibration of the Chandra X-Ray Observatory provided a unique base for developing detailed models of the optics and detectors. Using these models we have produced a set of simulations of the Chandra point spread function (PSF) which is available to the users via PSF library files. We describe here how the PSF models are generated and the design and content of the Chandra PSF library files.

  16. Monitoring variable X-ray sources in nearby galaxies

    Science.gov (United States)

    Kong, A. K. H.

    2010-12-01

    In the last decade, it has been possible to monitor variable X-ray sources in nearby galaxies. In particular, since the launch of Chandra, M31 has been regularly observed. It is perhaps the only nearby galaxy which is observed by an X-ray telescope regularly throughout operation. With 10 years of observations, the center of M31 has been observed with Chandra for nearly 1 Msec and the X-ray skies of M31 consist of many transients and variables. Furthermore, the X-ray Telescope of Swift has been monitoring several ultraluminous X-ray sources in nearby galaxies regularly. Not only can we detect long-term X-ray variability, we can also find spectral variation as well as possible orbital period. In this talk, I will review some of the important Chandra and Swift monitoring observations of nearby galaxies in the past 10 years. I will also present a "high-definition" movie of M31 and discuss the possibility of detecting luminous transients in M31 with MAXI.

  17. A Chandra High-Resolution X-ray Image of Centaurus A.

    Science.gov (United States)

    Kraft; Forman; Jones; Kenter; Murray; Aldcroft; Elvis; Evans; Fabbiano; Isobe; Jerius; Karovska; Kim; Prestwich; Primini; Schwartz; Schreier; Vikhlinin

    2000-03-01

    We present first results from a Chandra X-Ray Observatory observation of the radio galaxy Centaurus A with the High-Resolution Camera. All previously reported major sources of X-ray emission including the bright nucleus, the jet, individual point sources, and diffuse emission are resolved or detected. The spatial resolution of this observation is better than 1&arcsec; in the center of the field of view and allows us to resolve X-ray features of this galaxy not previously seen. In particular, we resolve individual knots of emission in the inner jet and diffuse emission between the knots. All of the knots are diffuse at the 1&arcsec; level, and several exhibit complex spatial structure. We find the nucleus to be extended by a few tenths of an arcsecond. Our image also suggests the presence of an X-ray counterjet. Weak X-ray emission from the southwest radio lobe is also seen, and we detect 63 pointlike galactic sources (probably X-ray binaries and supernova remnants) above a luminosity limit of approximately 1.7x1037 ergs s-1.

  18. Invited Review Article: The Chandra X-ray Observatory

    Science.gov (United States)

    Schwartz, Daniel A.

    2014-06-01

    The Chandra X-ray Observatory is an orbiting x-ray telescope facility. It is one of the National Aeronautics and Space Administration's four "Great Observatories" that collectively have carried out astronomical observations covering the infrared through gamma-ray portion of the electromagnetic spectrum. Chandra is used by astronomers world-wide to acquire imaging and spectroscopic data over a nominal 0.1-10 keV (124-1.24 Å) range. We describe the three major parts of the observatory: the telescope, the spacecraft systems, and the science instruments. This article will emphasize features of the design and development driven by some of the experimental considerations unique to x-ray astronomy. We will update the on-orbit performance and present examples of the scientific highlights.

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

    Science.gov (United States)

    Weisskopf, Martin C.

    2010-01-01

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

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

    Science.gov (United States)

    1999-04-01

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

  1. THE CHANDRA SOURCE CATALOG

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  2. The Chandra Source Catalog

    Science.gov (United States)

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

    2010-07-01

    The Chandra Source Catalog (CSC) is a general purpose virtual X-ray astrophysics facility that provides access to a carefully selected set of generally useful quantities for individual X-ray sources, and is designed to satisfy the needs of a broad-based group of scientists, including those who may be less familiar with astronomical data analysis in the X-ray regime. The first release of the CSC includes information about 94,676 distinct X-ray sources detected in a subset of public Advanced CCD Imaging Spectrometer imaging observations from roughly the first eight years of the Chandra mission. This release of the catalog includes point and compact sources with observed spatial extents lsim30''. The catalog (1) provides access to the best estimates of the X-ray source properties for detected sources, with good scientific fidelity, and directly supports scientific analysis using the individual source data; (2) facilitates analysis of a wide range of statistical properties for classes of X-ray sources; and (3) provides efficient access to calibrated observational data and ancillary data products for individual X-ray sources, so that users can perform detailed further analysis using existing tools. The catalog includes real X-ray sources detected with flux estimates that are at least 3 times their estimated 1σ uncertainties in at least one energy band, while maintaining the number of spurious sources at a level of lsim1 false source per field for a 100 ks observation. For each detected source, the CSC provides commonly tabulated quantities, including source position, extent, multi-band fluxes, hardness ratios, and variability statistics, derived from the observations in which the source is detected. In addition to these traditional catalog elements, for each X-ray source the CSC includes an extensive set of file-based data products that can be manipulated interactively, including source images, event lists, light curves, and spectra from each observation in which a

  3. The Chandra Source Catalog: X-ray Aperture Photometry

    Science.gov (United States)

    Kashyap, Vinay; Primini, F. A.; Glotfelty, K. J.; Anderson, C. S.; Bonaventura, N. R.; Chen, J. C.; Davis, J. E.; Doe, S. M.; Evans, I. N.; Evans, J. D.; Fabbiano, G.; Galle, E. C.; Gibbs, D. G., II; Grier, J. D.; Hain, R.; Hall, D. M.; Harbo, P. N.; He, X.; Houck, J. C.; Karovska, M.; Lauer, J.; McCollough, M. L.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Nowak, M. A.; Plummer, D. A.; Refsdal, B. L.; Rots, A. H.; Siemiginowska, A. L.; Sundheim, B. A.; Tibbetts, M. S.; van Stone, D. W.; Winkelman, S. L.; Zografou, P.

    2009-09-01

    The Chandra Source Catalog (CSC) represents a reanalysis of the entire ACIS and HRC imaging observations over the 9-year Chandra mission. We describe here the method by which fluxes are measured for detected sources. Source detection is carried out on a uniform basis, using the CIAO tool wavdetect. Source fluxes are estimated post-facto using a Bayesian method that accounts for background, spatial resolution effects, and contamination from nearby sources. We use gamma-function prior distributions, which could be either non-informative, or in case there exist previous observations of the same source, strongly informative. The current implementation is however limited to non-informative priors. The resulting posterior probability density functions allow us to report the flux and a robust credible range on it.

  4. Chandra reveals a black hole X-ray binary within the ultraluminous supernova remnant MF 16

    Science.gov (United States)

    Roberts, T. P.; Colbert, E. J. M.

    2003-06-01

    We present evidence, based on Chandra ACIS-S observations of the nearby spiral galaxy NGC 6946, that the extraordinary X-ray luminosity of the MF 16 supernova remnant actually arises in a black hole X-ray binary. This conclusion is drawn from the point-like nature of the X-ray source, its X-ray spectrum closely resembling the spectrum of other ultraluminous X-ray sources thought to be black hole X-ray binary systems, and the detection of rapid hard X-ray variability from the source. We briefly discuss the nature of the hard X-ray variability, and the origin of the extreme radio and optical luminosity of MF 16 in light of this identification.

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

    Science.gov (United States)

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

    2012-05-01

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

  6. THE CHANDRA X-RAY SURVEY OF PLANETARY NEBULAE (CHANPLANS): PROBING BINARITY, MAGNETIC FIELDS, AND WIND COLLISIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kastner, J. H.; Montez, R. Jr.; Rapson, V. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA (United States); Frew, D. J.; De Marco, O.; Parker, Q. A. [Department of Physics and Astronomy and Macquarie Research Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109 (Australia); Miszalski, B. [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Sahai, R. [Jet Propulsion Laboratory, California Institute of Technology, MS 183-900, Pasadena, CA 91109 (United States); Blackman, E.; Frank, A. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Chu, Y.-H. [Department of Astronomy, University of Illinois, Champagne-Urbana, IL (United States); Guerrero, M. A. [Instituto de Astrofisica de Astronomia, Glorieta de la Astronomia s/n, Granada 18008 (Spain); Lopez, J. A. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Campus Ensenada, Apdo. Postal 22860, Ensenada, B. C. (Mexico); Zijlstra, A. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Behar, E. [Department of Physics, Technion (Israel); Bujarrabal, V. [Observatorio Astronomico Nacional, Apartado 112, E-28803, Alcala de Henares (Spain); Corradi, R. L. M. [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Nordhaus, J. [Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY 14623 (United States); Sandin, C., E-mail: jhk@cis.rit.edu, E-mail: soker@physics.technion.ac.il, E-mail: eva.villaver@uam.es [Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); and others

    2012-08-15

    We present an overview of the initial results from the Chandra Planetary Nebula Survey (CHANPLANS), the first systematic (volume-limited) Chandra X-Ray Observatory survey of planetary nebulae (PNe) in the solar neighborhood. The first phase of CHANPLANS targeted 21 mostly high-excitation PNe within {approx}1.5 kpc of Earth, yielding four detections of diffuse X-ray emission and nine detections of X-ray-luminous point sources at the central stars (CSPNe) of these objects. Combining these results with those obtained from Chandra archival data for all (14) other PNe within {approx}1.5 kpc that have been observed to date, we find an overall X-ray detection rate of {approx}70% for the 35 sample objects. Roughly 50% of the PNe observed by Chandra harbor X-ray-luminous CSPNe, while soft, diffuse X-ray emission tracing shocks-in most cases, 'hot bubbles'-formed by energetic wind collisions is detected in {approx}30%; five objects display both diffuse and point-like emission components. The presence (or absence) of X-ray sources appears correlated with PN density structure, in that molecule-poor, elliptical nebulae are more likely to display X-ray emission (either point-like or diffuse) than molecule-rich, bipolar, or Ring-like nebulae. All but one of the point-like CSPNe X-ray sources display X-ray spectra that are harder than expected from hot ({approx}100 kK) central stars emitting as simple blackbodies; the lone apparent exception is the central star of the Dumbbell nebula, NGC 6853. These hard X-ray excesses may suggest a high frequency of binary companions to CSPNe. Other potential explanations include self-shocking winds or PN mass fallback. Most PNe detected as diffuse X-ray sources are elliptical nebulae that display a nested shell/halo structure and bright ansae; the diffuse X-ray emission regions are confined within inner, sharp-rimmed shells. All sample PNe that display diffuse X-ray emission have inner shell dynamical ages {approx}< 5 Multiplication

  7. X-ray Point Source Populations in Spiral and Elliptical Galaxies

    Science.gov (United States)

    Colbert, E.; Heckman, T.; Weaver, K.; Strickland, D.

    2002-01-01

    The hard-X-ray luminosity of non-active galaxies has been known to be fairly well correlated with the total blue luminosity since the days of the Einstein satellite. However, the origin of this hard component was not well understood. Some possibilities that were considered included X-ray binaries, extended upscattered far-infrared light via the inverse-Compton process, extended hot 107 K gas (especially in ellipitical galaxies), or even an active nucleus. Chandra images of normal, elliptical and starburst galaxies now show that a significant amount of the total hard X-ray emission comes from individual point sources. We present here spatial and spectral analyses of the point sources in a small sample of Chandra obervations of starburst galaxies, and compare with Chandra point source analyses from comparison galaxies (elliptical, Seyfert and normal galaxies). We discuss possible relationships between the number and total hard luminosity of the X-ray point sources and various measures of the galaxy star formation rate, and discuss possible options for the numerous compact sources that are observed.

  8. Chandra Source Catalog: Background Determination and Source Detection

    Science.gov (United States)

    McCollough, Michael L.; Rots, A. H.; Primini, F. A.; Evans, I. N.; Glotfelty, K. J.; Hain, R.; Anderson, C. S.; Bonaventura, N. R.; Chen, J. C.; Davis, J. E.; Doe, S. M.; Evans, J. D.; Fabbiano, G.; Galle, E.; Gibbs, D. G.; Grier, J. D.; Hall, D. M.; Harbo, P. N.; He, X.; Houck, J. C.; Karovska, M.; Lauer, J.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Nowak, M. A.; Plummer, D. A.; Refsdal, B. L.; Siemiginowska, A. L.; Sundheim, B. A.; Tibbetts, M. S.; Van Stone, D. W.; Winkelman, S. L.; Zografou, P.

    2009-01-01

    The Chandra Source Catalog (CSC) is a major project in which all of the pointed imaging observations taken by the Chandra X-Ray Observatory will used to generate the most extensive X-ray source catalog produced to date. Early in the development of the CSC it was recognized that the ability to estimate local background levels in an automated fashion would be critical for essential CSC tasks such as source detection, photometry, sensitivity estimates, and source characterization. We present a discussion of how such background maps are created directly from the Chandra data and how they are used in source detection. The general background for Chandra observations is rather smoothly varying, containing only low spatial frequency components. However, in the case of ACIS data, a high spatial frequency component is added that is due to the readout streaks of the CCD chips. We discuss how these components can be estimated reliably using the Chandra data and what limitations and caveats should be considered in their use. We will discuss the source detection algorithm used for the CSC and the effects of the background images on the detection results. We will also touch on some the Catalog Inclusion and Quality Assurance criteria applied to the source detection results. This work is supported by NASA contract NAS8-03060 (CXC).

  9. Multiwavelength study of Chandra X-ray sources in the Antennae

    Science.gov (United States)

    Clark, D. M.; Eikenberry, S. S.; 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.

    2011-01-01

    We use Wide-field InfraRed Camera (WIRC) infrared (IR) images of the Antennae (NGC 4038/4039) together with the extensive catalogue of 120 X-ray point sources 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 that we first identified. 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, Ks≈ 16 mag, with (J-Ks) = 1.1 mag. We then use archival Hubble Space Telescope (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 cluster counterparts, we find optical matches for 27 of these sources. Using Bruzual-Charlot spectral evolutionary models, we find that most clusters associated with an X-ray source are massive, and young, ˜ 106 yr.

  10. Using the Chandra Source-Finding Algorithm to Automatically Identify Solar X-ray Bright Points

    Science.gov (United States)

    Adams, Mitzi L.; Tennant, A.; Cirtain, J. M.

    2009-01-01

    This poster details a technique of bright point identification that is used to find sources in Chandra X-ray data. The algorithm, part of a program called LEXTRCT, searches for regions of a given size that are above a minimum signal to noise ratio. The algorithm allows selected pixels to be excluded from the source-finding, thus allowing exclusion of saturated pixels (from flares and/or active regions). For Chandra data the noise is determined by photon counting statistics, whereas solar telescopes typically integrate a flux. Thus the calculated signal-to-noise ratio is incorrect, but we find we can scale the number to get reasonable results. For example, Nakakubo and Hara (1998) find 297 bright points in a September 11, 1996 Yohkoh image; with judicious selection of signal-to-noise ratio, our algorithm finds 300 sources. To further assess the efficacy of the algorithm, we analyze a SOHO/EIT image (195 Angstroms) and compare results with those published in the literature (McIntosh and Gurman, 2005). Finally, we analyze three sets of data from Hinode, representing different parts of the decline to minimum of the solar cycle.

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

    Science.gov (United States)

    2000-06-01

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

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

    DEFF Research Database (Denmark)

    Hong, JaeSub; Mori, Kaya; Hailey, Charles J.

    2016-01-01

    persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr. A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra...

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

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, M.; Kastner, J. H. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Montez, R. Jr. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA (United States); Frew, D. J.; De Marco, O.; Parker, Q. A. [Department of Physics and Astronomy and Macquarie Research Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109 (Australia); Jones, D. [Departamento de Física, Universidad de Atacama, Copayapu 485, Copiapó (Chile); Miszalski, B. [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Sahai, R. [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Blackman, E.; Frank, A. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Chu, Y.-H. [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL (United States); Guerrero, M. A. [Instituto de Astrofísica de Andalucía, IAA-CSIC, Glorieta de la Astronomía s/n, Granada, E-18008 (Spain); Lopez, J. A. [Instituto de Astronomía, Universidad Nacional Autonoma de Mexico, Campus Ensenada, Apdo. Postal 22860, Ensenada, B. C. (Mexico); Zijlstra, A. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Bujarrabal, V. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Corradi, R. L. M. [Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Nordhaus, J. [NSF Astronomy and Astrophysics Fellow, Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY 14623 (United States); and others

    2014-10-20

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

  14. The Chandra Source Catalog: Background Determination and Source Detection

    Science.gov (United States)

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

    2009-09-01

    The Chandra Source Catalog (CSC) is a major project in which all of the pointed imaging observations taken by the Chandra X-Ray Observatory are used to generate one of the most extensive X-ray source catalog produced to date. Early in the development of the CSC it was recognized that the ability to estimate local background levels in an automated fashion would be critical for essential CSC tasks such as source detection, photometry, sensitivity estimates, and source characterization. We present a discussion of how such background maps are created directly from the Chandra data and how they are used in source detection. The general background for Chandra observations is rather smoothly varying, containing only low spatial frequency components. However, in the case of ACIS data, a high spatial frequency component is added that is due to the readout streaks of the CCD chips. We discuss how these components can be estimated reliably using the Chandra data and what limitations and caveats should be considered in their use. We will discuss the source detection algorithm used for the CSC and the effects of the background images on the detection results. We will also touch on some the Catalog Inclusion and Quality Assurance criteria applied to the source detection results. This work is supported by NASA contract NAS8-03060 (CXC).

  15. A Chandra Survey of Milky Way Globular Clusters. I. Emissivity and Abundance of Weak X-Ray Sources

    Science.gov (United States)

    Cheng, Zhongqun; Li, Zhiyuan; Xu, Xiaojie; Li, Xiangdong

    2018-05-01

    Based on archival Chandra data, we have carried out an X-ray survey of 69, or nearly half the known population of, Milky Way globular clusters (GCs), focusing on weak X-ray sources, mainly cataclysmic variables (CVs) and coronally active binaries (ABs). Using the cumulative X-ray luminosity per unit stellar mass (i.e., X-ray emissivity) as a proxy of the source abundance, we demonstrate a paucity (lower by 41% ± 27% on average) of weak X-ray sources in most GCs relative to the field, which is represented by the Solar Neighborhood and Local Group dwarf elliptical galaxies. We also revisit the mutual correlations among the cumulative X-ray luminosity (L X), cluster mass (M), and stellar encounter rate (Γ), finding {L}{{X}}\\propto {M}0.74+/- 0.13, {L}{{X}}\\propto {{{Γ }}}0.67+/- 0.07 and {{Γ }}\\propto {M}1.28+/- 0.17. The three quantities can further be expressed as {L}{{X}}\\propto {M}0.64+/- 0.12 {{{Γ }}}0.19+/- 0.07, which indicates that the dynamical formation of CVs and ABs through stellar encounters in GCs is less dominant than previously suggested, and that the primordial formation channel has a substantial contribution. Taking these aspects together, we suggest that a large fraction of primordial, soft binaries have been disrupted in binary–single or binary–binary stellar interactions before they could otherwise evolve into X-ray-emitting close binaries, whereas the same interactions also have led to the formation of new close binaries. No significant correlations between {L}{{X}}/{L}K and cluster properties, including dynamical age, metallicity, and structural parameters, are found.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-02-01

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

  18. Distant Galaxies, Black Holes and Other Celestial Phenomena: NASA's Chandra X-ray Observatory Marks Four Years of Discovery Firsts

    Science.gov (United States)

    2003-09-01

    Launched in 1999, NASA's Chandra X-ray Observatory promised to be one of the world's most powerful tools to better understand the structure and evolution of the universe - and it has lived up to expectations. "In four short years, Chandra has achieved numerous scientific firsts, revealing new details on all categories of astronomical objects including distant galaxies, planets, black holes and stars," said Chandra project scientist Dr. Martin C. Weisskopf of NASA's Marshall Space Flight Center in Huntsville, Ala. "In the last year alone, Chandra has generated the most sensitive or 'deepest' X-ray exposure ever made, shed new light on the planet Mars, and made several new discoveries involving supermassive black holes," added Weisskopf, who has dedicated nearly 30 years to the Chandra program. The deepest X-ray exposure, Chandra Deep Field North, captured for 23 days an area of the sky one-fifth the size of the full moon. Even though the faintest sources detected produced only one X-ray photon every four days, Chandra found more than 600 X-ray sources -- most of them supermassive black holes in galaxy centers. If the number of black holes seen in that area of the sky were typical, 300 million supermassive black holes would be detectable over the whole sky. In our own solar system, another Chandra image offered scientists their first look at X-rays from Mars . Not only did Chandra detect X-rays in the sparse upper atmosphere 750 miles above the planet, it also offered evidence for a faint halo of X-rays extending out 4,350 miles above the Martian surface. "In its fourth year of operation, Chandra continues to prove itself an engineering marvel," said Chandra Program Manager Keith Hefner at NASA's Marshall Center. "At its highest point, it travels one-third of the way to the Moon, yet it consistently delivers breathtaking results gleaned from millions, sometimes billions, of light years away." Some of Chandra's most intriguing discoveries involved black holes

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

    Science.gov (United States)

    1999-12-01

    Through a combination of serendipity and skill, scientists have used NASA's Chandra X-ray Observatory to capture a rare glimpse of X-radiation from the early phases of a supernova, one of the most violent events in nature. Although more than a thousand supernovas have been observed by optical astronomers, the early X-ray glow from the explosions has been detected in less than a dozen cases. The Chandra observations were made under the direction of a team of scientists from the Massachusetts Institute of Technology (MIT) in Cambridge, led by Walter Lewin and his graduate student, Derek Fox. When combined with simultaneous observations by radio and optical telescopes, the X-ray observations tell about the thickness of the shell that was blown off, its density, its speed, and how much material was shed by the star before it exploded. Chandra observed an X-ray glow from SN1999em with the total power of 50,000 suns. Ten days later it observed the supernova for another nine hours, and found that the X rays had faded to half their previous intensity. The optical luminosity, which had the brightness of 200 million suns, had faded somewhat less. No radio emission was detected at any time. With this information, the MIT group and their colleagues are already piecing together a picture of the catastrophic explosion. Observations by optical astronomers showed that SN1999em was a Type II supernova produced by the collapse of the core of a star ten or more times as massive as the Sun. The intense heat generated in the collapse produces a cataclysmic rebound that sends high speed debris flying outward at speeds in excess of 20 million miles per hour. The debris crashes into matter shed by the former star before the explosion. This awesome collision generates shock waves that heat expanding debris to three million degrees. The X-ray glow from this hot gas was detected by Chandra and gives astrophysicists a better understanding of the dynamics of the explosion, as well as the

  20. Statistical Characterization of the Chandra Source Catalog

    Science.gov (United States)

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

    2011-06-01

    The first release of the Chandra Source Catalog (CSC) contains ~95,000 X-ray sources in a total area of 0.75% of the entire sky, using data from ~3900 separate ACIS observations of a multitude of different types of X-ray sources. In order to maximize the scientific benefit of such a large, heterogeneous data set, careful characterization of the statistical properties of the catalog, i.e., completeness, sensitivity, false source rate, and accuracy of source properties, is required. Characterization efforts of other large Chandra catalogs, such as the ChaMP Point Source Catalog or the 2 Mega-second Deep Field Surveys, while informative, cannot serve this purpose, since the CSC analysis procedures are significantly different and the range of allowable data is much less restrictive. We describe here the characterization process for the CSC. This process includes both a comparison of real CSC results with those of other, deeper Chandra catalogs of the same targets and extensive simulations of blank-sky and point-source populations.

  1. Chandra X-ray Data Analysis in Educational Environments

    Science.gov (United States)

    Matilsky, T.; Etkina, E.; Lestition, K.; Mandel, E.; Joye, W.

    2004-12-01

    Recent progress in both software and remote connectivity capabilities have made it possible for authentic data analysis tasks to be presented in a wide range of educational venues. No longer are precollege teachers and students, and interested members of the public limited by their lack of access to the scientific workstations and UNIX-based imaging and analytical software used by the research community. Through a suite of programs that couples a simplified graphical user interface using the "DS9" imaging software with a "virtual observatory" capability that processes the analytical algorithms used by X-ray astronomers, we can access archived Chandra observations and generate images, as well as light curves, energy spectra, power spectra and other common examples of science tasks. The system connects to a remote UNIX server, but the user may be sited on a PC or Mac platform. Furthermore, the use of VNC (a remote desktop display environment) allows a teacher to view, comment on and debug any analysis task in real time, from anywhere in the world, and across any computer platform. This makes these programs especially useful in distance learning settings. We have developed, tested and used these capabilities in a wide variety of educational arenas, from 4 week intensive courses in X-ray astronomy research techniques for precollege students and teachers, to one day teacher enrichment workshops, to modules of classroom activities suitable for precollege grade levels, using a variety of cosmic X-ray sources. Examples using archived Chandra observations will be presented demonstrating the flexibility and usefulness of these resources.

  2. X-Ray and Near-Infrared Spectroscopy of Dim X-Ray Point Sources Constituting the Galactic Ridge X-Ray Emission

    Directory of Open Access Journals (Sweden)

    Kumiko Morihana

    2014-12-01

    Full Text Available We present the results of X-ray and Near-Infrared observations of the Galactic Ridge X-ray Emission (GRXE. We extracted 2,002 X-ray point sources in the Chandra Bulge Field (l =0°.113, b = 1°.424 down to ~10-14.8 ergscm-2s-1 in 2-8 keV band with the longest observation (900 ks of the GRXE. Based on X-ray brightness and hardness, we classied the X-ray point sources into three groups: A (hard, B (soft and broad spectrum, and C (soft and peaked spectrum. In order to know populations of the X-ray point sources, we carried out NIR imaging and spectroscopy observation. We identied 11% of X-ray point sources with NIR and extracted NIR spectra for some of them. Based on X-ray and NIR properties, we concluded that non-thermal sources in the group A are mostly active galactic nuclei and the thermal sources are mostly white dwarf binaries such as cataclysmic variables (CVs and Pre-CVs. We concluded that the group B and C sources are X-ray active stars in flare and quiescence, respectively.

  3. Chandra Source Catalog: User Interface

    Science.gov (United States)

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

    2009-09-01

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

  4. Real Time Space Weather Support for Chandra X-ray Observatory Operations

    Science.gov (United States)

    O'Dell, S. L.; Miller, S.; Minow, J. I.; Wolk, S.; Aldcroft, T. L.; Spitzbart, B. D.; Swartz, D. A.

    2012-12-01

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

  5. STATISTICAL CHARACTERIZATION OF THE CHANDRA SOURCE CATALOG

    International Nuclear Information System (INIS)

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

    2011-01-01

    The first release of the Chandra Source Catalog (CSC) contains ∼95,000 X-ray sources in a total area of 0.75% of the entire sky, using data from ∼3900 separate ACIS observations of a multitude of different types of X-ray sources. In order to maximize the scientific benefit of such a large, heterogeneous data set, careful characterization of the statistical properties of the catalog, i.e., completeness, sensitivity, false source rate, and accuracy of source properties, is required. Characterization efforts of other large Chandra catalogs, such as the ChaMP Point Source Catalog or the 2 Mega-second Deep Field Surveys, while informative, cannot serve this purpose, since the CSC analysis procedures are significantly different and the range of allowable data is much less restrictive. We describe here the characterization process for the CSC. This process includes both a comparison of real CSC results with those of other, deeper Chandra catalogs of the same targets and extensive simulations of blank-sky and point-source populations.

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

    Science.gov (United States)

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

    2013-01-01

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

  7. Optical Counterparts for Low-Luminosity X-ray Sources in Omega Centauri

    Science.gov (United States)

    Cool, Adrienne

    2002-07-01

    We propose to use narrow-band HAlpha imaging with ACS to search for the optical counterparts of low-luminosity X-ray sources {Lx 2 x 10^30 - 5 x 10^32 erg/s} in the globular cluster Omega Centauri. With 9 WFC fields, we will cover the inner two core radii of the cluster, and encompass about 90 of the faint sources we have identified with Chandra. Approximately 30-50 of these sources should be cluster members, the remainder being mostly background galaxies plus a smaller number of foreground stars. This large population of low-Lx cluster X-ray sources is second only to the more than 100 faint sources recently discovered in 47 Tuc with Chandra {Grindlay et al. 2001a}, which have been identified as a mixture of cataclysmic variables, quiescent low-mass X-ray binaries, millisecond pulsars, and coronally active main-sequence binaries. Our Cycle 6 WFPC2 program successfully identified 2 of the 3 then-known faint X-ray sources in the core of Omega Cen using H-alpha imaging. We now propose to expand the areal coverage by a factor of about 18 to encompass the much larger number of sources that have since been discovered with Chandra. The extreme crowding in the central regions of Omega Cen requires the resolution of HST to obtain optical IDs. These identifications are key to making meaningful comparisons between the populations of faint X-ray sources in different clusters, in an effort to understand their origins and role in cluster dynamics.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-09-20

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

  9. Six Years Into Its Mission, NASA's Chandra X-ray Observatory Continues to Achieve Scientific Firsts

    Science.gov (United States)

    2005-08-01

    In August 1999, NASA's Chandra X-ray Observatory opened for business. Six years later, it continues to achieve scientific firsts. "When Chandra opened its sunshade doors for the first time, it opened the possibility of studying the X-ray emission of the universe with unprecedented clarity," said Chandra project scientist Dr. Martin Weisskopf of NASA's Marshall Space Flight Center in Huntsville, Ala. "Already surpassing its goal of a five-year life, Chandra continues to rewrite textbooks with discoveries about our own solar system and images of celestial objects as far as billions of light years away." Based on the observatory's outstanding results, NASA Headquarters in Washington decided in 2001 to extend Chandra s mission from five years to ten. During the observatory s sixth year of operation, auroras from Jupiter, X-rays from Saturn, and the early days of our solar system were the focus of Chandra discoveries close to home -- discoveries with the potential to better understand the dynamics of life on Earth. Jupiter's auroras are the most spectacular and active auroras in the solar system. Extended Chandra observations revealed that Jupiter s auroral X-rays are caused by highly charged particles crashing into the atmosphere above Jupiter's poles. These results gave scientists information needed to compare Jupiter's auroras with those from Earth, and determine if they are triggered by different cosmic and planetary events. Mysterious X-rays from Saturn also received attention, as Chandra completed the first observation of a solar X-ray flare reflected from Saturn's low-latitudes, the region that correlates to Earth's equator and tropics. This observation led scientists to conclude the ringed planet may act as a mirror, reflecting explosive activity from the sun. Solar-storm watchers on Earth might see a surprising benefit. The results imply scientists could use giant planets like Saturn as remote-sensing tools to help monitor X-ray flaring on portions of the sun

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-10

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

  12. The Role of Project Science in the Chandra X-Ray Observatory

    Science.gov (United States)

    O'Dell, Stephen L.; Weisskopf, Martin C.

    2006-01-01

    The Chandra X-Ray Observatory, one of NASA's Great Observatories, has an outstanding record of scientific and technical success. This success results from the efforts of a team comprising NASA, its contractors, the Smithsonian Astrophysical Observatory, the instrument groups, and other elements of the scientific community, including thousands of scientists who utilize this powerful facility for astrophysical research. We discuss the role of NASA Project Science in the formulation, development, calibration, and operation of the Chandra X-ray Observatory. In addition to representing the scientific community within the Project, Project Science performed what we term "science systems engineering". This activity encompasses translation of science requirements into technical requirements and assessment of the scientific impact of programmatic and technical trades. We briefly describe several examples of science systems engineering conducted by Chandra Project Science.

  13. CHANDRA OBSERVATIONS OF A 1.9 kpc SEPARATION DOUBLE X-RAY SOURCE IN A CANDIDATE DUAL ACTIVE GALACTIC NUCLEUS GALAXY AT z = 0.16

    International Nuclear Information System (INIS)

    Comerford, Julia M.; Pooley, David; Gerke, Brian F.; Madejski, Greg M.

    2011-01-01

    We report Chandra observations of a double X-ray source in the z = 0.1569 galaxy SDSS J171544.05+600835.7. The galaxy was initially identified as a dual active galactic nucleus (AGN) candidate based on the double-peaked [O III] λ5007 emission lines, with a line-of-sight velocity separation of 350 km s -1 , in its Sloan Digital Sky Survey spectrum. We used the Kast Spectrograph at Lick Observatory to obtain two long-slit spectra of the galaxy at two different position angles, which reveal that the two Type 2 AGN emission components have not only a velocity offset, but also a projected spatial offset of 1.9 h -1 70 kpc on the sky. Chandra/ACIS observations of two X-ray sources with the same spatial offset and orientation as the optical emission suggest that the galaxy most likely contains Compton-thick dual AGNs, although the observations could also be explained by AGN jets. Deeper X-ray observations that reveal Fe K lines, if present, would distinguish between the two scenarios. The observations of a double X-ray source in SDSS J171544.05+600835.7 are a proof of concept for a new, systematic detection method that selects promising dual AGN candidates from ground-based spectroscopy that exhibits both velocity and spatial offsets in the AGN emission features.

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

    Science.gov (United States)

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

    2004-01-01

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

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

    Science.gov (United States)

    Weisskopf, Martin C.

    2012-01-01

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

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

    Science.gov (United States)

    Weisskopf, Martin

    2011-01-01

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

  17. VizieR Online Data Catalog: ChaMP X-ray point source catalog (Kim+, 2007)

    Science.gov (United States)

    Kim, M.; Kim, D.-W.; 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.

    2009-01-01

    We present the Chandra Multiwavelength Project (ChaMP) X-ray point source catalog with ~6800 X-ray sources detected in 149 Chandra observations covering ~10deg2. The full ChaMP catalog sample is 7 times larger than the initial published ChaMP catalog. The exposure time of the fields in our sample ranges from 0.9 to 124ks, corresponding to a deepest X-ray flux limit of f0.5-8.0=9x10-16ergs/cm2/s. 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 eight 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. (10 data files).

  18. CHANDRA OBSERVATIONS OF SN 1987A: THE SOFT X-RAY LIGHT CURVE REVISITED

    Energy Technology Data Exchange (ETDEWEB)

    Helder, E. A.; Broos, P. S.; Burrows, D. N. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Dewey, D. [MIT Kavli Institute, Cambridge, MA 02139 (United States); Dwek, E. [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McCray, R. [JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309 (United States); Park, S. [Department of Physics, University of Texas at Arlington, Box 19059, Arlington, TX 76019 (United States); Racusin, J. L. [NASA, Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States); Zhekov, S. A. [Space Research and Technology Institute, Akad. G. Bonchev str., bl.1, Sofia 1113 (Bulgaria)

    2013-02-10

    We report on the present stage of SN 1987A as observed by the Chandra X-Ray Observatory. We reanalyze published Chandra observations and add three more epochs of Chandra data to get a consistent picture of the evolution of the X-ray fluxes in several energy bands. We discuss the implications of several calibration issues for Chandra data. Using the most recent Chandra calibration files, we find that the 0.5-2.0 keV band fluxes of SN 1987A have increased by {approx}6 Multiplication-Sign 10{sup -13} erg s{sup -1} cm{sup -2} per year since 2009. This is in contrast with our previous result that the 0.5-2.0 keV light curve showed a sudden flattening in 2009. Based on our new analysis, we conclude that the forward shock is still in full interaction with the equatorial ring.

  19. The Chandra Source Catalog: Spectral Properties

    Science.gov (United States)

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

    2009-09-01

    The first release of the Chandra Source Catalog (CSC) contains all sources identified from eight years' worth of publicly accessible observations. The vast majority of these sources have been observed with the ACIS detector and have spectral information in 0.5-7 keV energy range. Here we describe the methods used to automatically derive spectral properties for each source detected by the standard processing pipeline and included in the final CSC. Hardness ratios were calculated for each source between pairs of energy bands (soft, medium and hard) using the Bayesian algorithm (BEHR, Park et al. 2006). The sources with high signal to noise ratio (exceeding 150 net counts) were fit in Sherpa (the modeling and fitting application from the Chandra Interactive Analysis of Observations package, developed by the Chandra X-ray Center; see Freeman et al. 2001). Two models were fit to each source: an absorbed power law and a blackbody emission. The fitted parameter values for the power-law and blackbody models were included in the catalog with the calculated flux for each model. The CSC also provides the source energy flux computed from the normalizations of predefined power-law and black-body models needed to match the observed net X-ray counts. In addition, we provide access to data products for each source: a file with source spectrum, the background spectrum, and the spectral response of the detector. This work is supported by NASA contract NAS8-03060 (CXC).

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

    Science.gov (United States)

    Lisse, Carey M.

    2001-09-01

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

  1. Chandra and RXTE studies of the X-ray/gamma-ray millisecond pulsar PSR J0218+4232

    NARCIS (Netherlands)

    Kuiper, L.; Hermsen, W.; Stappers, B.W.

    2004-01-01

    We report on high-resolution spatial and timing observations of the millisecond pulsar PSR J0218+4232 performed with the Chandra X-ray Observatory (CXO) and the Rossi X-ray Timing Explorer (RXTE). With these observations we were able to study: (a) the possible spatial extent at X-ray energies of the

  2. Chandra Discovers X-Ray Ring Around Cosmic Powerhouse in Crab Nebula

    Science.gov (United States)

    1999-09-01

    After barely two months in space, NASA's Chandra X-ray Observatory has taken a stunning image of the Crab Nebula, the spectacular remains of a stellar explosion, and has revealed something never seen before: a brilliant ring around the nebula's heart. Combined with observations from the Hubble Space Telescope, the image provides important clues to the puzzle of how the cosmic "generator," a pulsing neutron star, energizes the nebula, which still glows brightly almost 1,000 years after the explosion. "The inner ring is unique," said Professor Jeff Hester of Arizona State University, Tempe, AZ. "It has never been seen before, and it should tell us a lot about how the energy from the pulsar gets into the nebula. It's like finding the transmission lines between the power plant and the light bulb." Professor Mal Ruderman of Columbia University, New York, NY, agreed. "The X-rays Chandra sees are the best tracer of where the energy is. With images such as these, we can directly diagnose what is going on." What is going on, according to Dr. Martin Weisskopf, Chandra Project Scientist from NASA's Marshall Space Flight Center, Huntsville, AL, is awesome. "The Crab pulsar is accelerating particles up to the speed of light and flinging them out into interstellar space at an incredible rate." The image shows tilted rings or waves of high-energy particles that appear to have been flung outward over the distance of a light year from the central star, and high-energy jets of particles blasting away from the neutron star in a direction perpendicular to the spiral. Hubble Space Telescope images have shown moving knots and wisps around the neutron star, and previous X-ray images have shown the outer parts of the jet and hinted at the ring structure. With Chandra's exceptional resolution, the jet can be traced all the way in to the neutron star, and the ring pattern clearly appears. The image was made with Chandra's Advanced CCD Imaging Spectrometer and High Energy Transmission

  3. The Chandra Source Catalog 2.0: Interfaces

    Science.gov (United States)

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

    2018-01-01

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

  4. The Chandra X-ray Observatory data processing system

    Science.gov (United States)

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

    2006-06-01

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

  5. The Chandra Source Catalog: Storage and Interfaces

    Science.gov (United States)

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

    2009-09-01

    The Chandra Source Catalog (CSC) is part of the Chandra Data Archive (CDA) at the Chandra X-ray Center. The catalog contains source properties and associated data objects such as images, spectra, and lightcurves. The source properties are stored in relational databases and the data objects are stored in files with their metadata stored in databases. The CDA supports different versions of the catalog: multiple fixed release versions and a live database version. There are several interfaces to the catalog: CSCview, a graphical interface for building and submitting queries and for retrieving data objects; a command-line interface for property and source searches using ADQL; and VO-compliant services discoverable though the VO registry. This poster describes the structure of the catalog and provides an overview of the interfaces.

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

    Science.gov (United States)

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

    2015-01-01

    During its first 16 years of operation, the cold (about -60 C) optical blocking filter of the Advanced CCD Imaging Spectrometer (ACIS), aboard the Chandra X-ray Observatory, has accumulated a growing layer of molecular contamination that attenuates low-energy x rays. Over the past few years, the accumulation rate, spatial distribution, and composition have changed. This evolution has motivated further analysis of contamination migration within and near the ACIS cavity, in part to evaluate potential bake-out scenarios intended to reduce the level of contamination. Keywords: X-ray astronomy, CCDs, contamination, modeling and simulation, spacecraft operations

  7. A CHANDRA SURVEY OF THE X-RAY PROPERTIES OF BROAD ABSORPTION LINE RADIO-LOUD QUASARS

    International Nuclear Information System (INIS)

    Miller, B. P.; Brandt, W. N.; Garmire, G. P.; Gibson, R. R.; Shemmer, O.

    2009-01-01

    This work presents the results of a Chandra study of 21 broad absorption line (BAL) radio-loud quasars (RLQs). We conducted a Chandra snapshot survey of 12 bright BAL RLQs selected from Sloan Digital Sky Survey Data/Faint Images of the Radio Sky data and possessing a wide range of radio and C IV absorption properties. Optical spectra were obtained nearly contemporaneously with the Hobby-Eberly Telescope; no strong flux or BAL variability was seen between epochs. In addition to the snapshot targets, we include in our sample nine additional BAL RLQs possessing archival Chandra coverage. We compare the properties of (predominantly high-ionization) BAL RLQs to those of non-BAL RLQs as well as to BAL radio-quiet quasars (RQQs) and non-BAL RQQs for context. All 12 snapshots and 8/9 archival BAL RLQs are detected, with observed X-ray luminosities less than those of non-BAL RLQs having comparable optical/UV luminosities by typical factors of 4.1-8.5. (BAL RLQs are also X-ray weak by typical factors of 2.0-4.5 relative to non-BAL RLQs having both comparable optical/UV and radio luminosities.) However, BAL RLQs are not as X-ray weak relative to non-BAL RLQs as are BAL RQQs relative to non-BAL RQQs. While some BAL RLQs have harder X-ray spectra than typical non-BAL RLQs, some have hardness ratios consistent with those of non-BAL RLQs, and there does not appear to be a correlation between X-ray weakness and spectral hardness, in contrast to the situation for BAL RQQs. RLQs are expected to have X-ray continuum contributions from both accretion-disk corona and small-scale jet emission. While the entire X-ray continuum in BAL RLQs cannot be obscured to the same degree as in BAL RQQs, we calculate that the jet is likely partially covered in many BAL RLQs. We comment briefly on implications for geometries and source ages in BAL RLQs.

  8. The Chandra Source Catalog: Statistical Characterization

    Science.gov (United States)

    Primini, Francis A.; Nowak, M. A.; Houck, J. C.; Davis, J. E.; Glotfelty, K. J.; Karovska, M.; Anderson, C. S.; Bonaventura, N. R.; Chen, J. C.; Doe, S. M.; Evans, I. N.; Evans, J. D.; Fabbiano, G.; Galle, E. C.; Gibbs, D. G., II; Grier, J. D.; Hain, R.; Hall, D. M.; Harbo, P. N.; He, X.; Lauer, J.; McCollough, M. L.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Plummer, D. A.; Refsdal, B. L.; Rots, A. H.; Siemiginowska, A. L.; Sundheim, B. A.; Tibbetts, M. S.; van Stone, D. W.; Winkelman, S. L.; Zografou, P.

    2009-09-01

    The Chandra Source Catalog (CSC) will ultimately contain more than ˜250000 x-ray sources in a total area of ˜1% of the entire sky, using data from ˜10000 separate ACIS and HRC observations of a multitude of different types of x-ray sources (see Evans et al. this conference). In order to maximize the scientific benefit of such a large, heterogeneous dataset, careful characterization of the statistical properties of the catalog, i.e., completeness, sensitivity, false source rate, and accuracy of source properties, is required. Our Characterization efforts include both extensive simulations of blank-sky and point source datasets, and detailed comparisons of CSC results with those of other x-ray and optical catalogs. We present here a summary of our characterization results for CSC Release 1 and preliminary plans for future releases. This work is supported by NASA contract NAS8-03060 (CXC).

  9. The Restless Universe - Understanding X-Ray Astronomy in the Age of Chandra and Newton

    Science.gov (United States)

    Schlegel, Eric M.

    2002-10-01

    Carl Sagan once noted that there is only one generation that gets to see things for the first time. We are in the midst of such a time right now, standing on the threshold of discovery in the young and remarkable field of X-ray astronomy. In The Restless Universe , astronomer Eric Schlegel offers readers an informative survey of this cutting-edge science. Two major space observatories launched in the last few years--NASA's Chandra and the European Newton --are now orbiting the Earth, sending back a gold mine of data on the X-ray universe. Schlegel, who has worked on the Chandra project for seven years, describes the building and launching of this space-based X-ray observatory. But the book goes far beyond the story of Chandra . What Schlegel provides here is the background a nonscientist would need to grasp the present and follow the future of X-ray astronomy. He looks at the relatively brief history of the field, the hardware used to detect X-rays, the satellites--past, present, and future--that have been or will be flown to collect the data, the way astronomers interpret this data, and, perhaps most important, the insights we have already learned as well as speculations about what we may soon discover. And throughout the book, Schlegel conveys the excitement of looking at the universe from the perspective brought by these new observatories and the sharper view they deliver. Drawing on observations obtained from Chandra, Newton , and previous X-ray observatories, The Restless Universe gives a first look at an exciting field which significantly enriches our understanding of the universe.

  10. Spectral state transitions of the Ultraluminous X-ray Source IC 342 X-1

    Science.gov (United States)

    Marlowe, H.; Kaaret, P.; Lang, C.; Feng, H.; Grisé, F.; Miller, N.; Cseh, D.; Corbel, S.; Mushotzky, R. F.

    2014-10-01

    We observed the Ultraluminous X-ray Source (ULX) IC 342 X-1 simultaneously in X-ray and radio with Chandra and the JVLA to investigate previously reported unresolved radio emission coincident with the ULX. The Chandra data reveal a spectrum that is much softer than observed previously and is well modelled by a thermal accretion disc spectrum. No significant radio emission above the rms noise level was observed within the region of the ULX, consistent with the interpretation as a thermal state though other states cannot be entirely ruled out with the current data. We estimate the mass of the black hole using the modelled inner disc temperature to be 30 M_{⊙} ≲ M√{cosi}≲ 200 M_{⊙} based on a Shakura-Sunyaev disc model. Through a study of the hardness and high-energy curvature of available X-ray observations, we find that the accretion state of X-1 is not determined by luminosity alone.

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

    Science.gov (United States)

    Lisse, C. M.

    2002-01-01

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

  12. Chandra X-ray Center Science Data Systems Regression Testing of CIAO

    Science.gov (United States)

    Lee, N. P.; Karovska, M.; Galle, E. C.; Bonaventura, N. R.

    2011-07-01

    The Chandra Interactive Analysis of Observations (CIAO) is a software system developed for the analysis of Chandra X-ray Observatory observations. An important component of a successful CIAO release is the repeated testing of the tools across various platforms to ensure consistent and scientifically valid results. We describe the procedures of the scientific regression testing of CIAO and the enhancements made to the testing system to increase the efficiency of run time and result validation.

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

    Science.gov (United States)

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

    2017-01-01

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

  14. Chandra Discovers the X-ray Signature of a Powerful Wind from a Galactic Microquasar

    Science.gov (United States)

    2000-11-01

    NASA's Chandra X-ray Observatory has detected, for the first time in X rays, a stellar fingerprint known as a P Cygni profile--the distinctive spectral signature of a powerful wind produced by an object in space. The discovery reveals a 4.5-million-mile-per-hour wind coming from a highly compact pair of stars in our galaxy, report researchers from Penn State and the Massachusetts Institute of Technology in a paper they will present on 8 November 2000 during a meeting of the High-Energy Astrophysics Division of the American Astronomical Society in Honolulu, Hawaii. The paper also has been accepted for publication in The Astrophysical Journal Letters. "To our knowledge, these are the first P Cygni profiles reported in X rays," say researchers Niel Brandt, assistant professor of astronomy and astrophysics at Penn State, and Norbert S. Schulz, research scientist at the Massachusetts Institute of Technology. The team made the discovery during their first observation of a binary-star system with the Chandra X-ray Observatory, which was launched into space in July 1999. The system, known as Circinus X-1, is located about 20,000 light years from Earth in the constellation Circinus near the Southern Cross. It contains a super-dense neutron star in orbit around a normal fusion-burning star like our Sun. Although Circinus X-1 was discovered in 1971, many properties of this system remain mysterious because Circinus X-1 lies in the galactic plane where obscuring dust and gas have blocked its effective study in many wavelengths. The P Cygni spectral profile, previously detected primarily at ultraviolet and optical wavelengths but never before in X rays, is the textbook tool astronomers rely on for probing stellar winds. The profile looks like the outline of a roller coaster, with one really big hill and valley in the middle, on a data plot with velocity on one axis and the flow rate of photons per second on the other. It is named after the famous star P Cygni, in which such

  15. The Chandra Source Catalog 2.0: Estimating Source Fluxes

    Science.gov (United States)

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

    2018-01-01

    The Second Chandra Source Catalog (CSC2.0) will provide information on approximately 316,000 point or compact extended x-ray sources, derived from over 10,000 ACIS and HRC-I imaging observations available in the public archive at the end of 2014. As in the previous catalog release (CSC1.1), fluxes for these sources will be determined separately from source detection, using a Bayesian formalism that accounts for background, spatial resolution effects, and contamination from nearby sources. However, the CSC2.0 procedure differs from that used in CSC1.1 in three important aspects. First, for sources in crowded regions in which photometric apertures overlap, fluxes are determined jointly, using an extension of the CSC1.1 algorithm, as discussed in Primini & Kashyap (2014ApJ...796…24P). Second, an MCMC procedure is used to estimate marginalized posterior probability distributions for source fluxes. Finally, for sources observed in multiple observations, a Bayesian Blocks algorithm (Scargle, et al. 2013ApJ...764..167S) is used to group observations into blocks of constant source flux.In this poster we present details of the CSC2.0 photometry algorithms and illustrate their performance in actual CSC2.0 datasets.This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  16. Identification of Hard X-ray Sources in Galactic Globular Clusters: Simbol-X Simulations

    Science.gov (United States)

    Servillat, M.

    2009-05-01

    Globular clusters harbour an excess of X-ray sources compared to the number of X-ray sources in the Galactic plane. It has been proposed that many of these X-ray sources are cataclysmic variables that have an intermediate magnetic field, i.e. intermediate polars, which remains to be confirmed and understood. We present here several methods to identify intermediate polars in globular clusters from multiwavelength analysis. First, we report on XMM-Newton, Chandra and HST observations of the very dense Galactic globular cluster NGC 2808. By comparing UV and X-ray properties of the cataclysmic variable candidates, the fraction of intermediate polars in this cluster can be estimated. We also present the optical spectra of two cataclysmic variables in the globular cluster M 22. The HeII (4868 Å) emission line in these spectra could be related to the presence of a magnetic field in these objects. Simulations of Simbol-X observations indicate that the angular resolution is sufficient to study X-ray sources in the core of close, less dense globular clusters, such as M 22. The sensitivity of Simbol-X in an extended energy band up to 80 keV will allow us to discriminate between hard X-ray sources (such as magnetic cataclysmic variables) and soft X-ray sources (such as chromospherically active binaries).

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

    Science.gov (United States)

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

    2013-01-01

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

  18. THE X-RAY FLUX DISTRIBUTION OF SAGITTARIUS A* AS SEEN BY CHANDRA

    International Nuclear Information System (INIS)

    Neilsen, J.; Anton Pannekoek, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands))" data-affiliation=" (Astronomical Institute, Anton Pannekoek, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands))" >Markoff, S.; Nowak, M. A.; Baganoff, F. K.; Dexter, J.; Witzel, G.; Barrière, N.; Li, Y.; Degenaar, N.; Fragile, P. C.; Gammie, C.; Goldwurm, A.; Grosso, N.; Haggard, D.

    2015-01-01

    We present a statistical analysis of the X-ray flux distribution of Sgr A* from the Chandra X-Ray Observatory's 3 Ms Sgr A* X-ray Visionary Project in 2012. Our analysis indicates that the observed X-ray flux distribution can be decomposed into a steady quiescent component, represented by a Poisson process with rate Q = (5.24 ± 0.08) × 10 –3  counts s –1 , and a variable component, represented by a power law process (dN/dF∝F –ξ , ξ=1.92 −0.02 +0.03 ). This slope matches our recently reported distribution of flare luminosities. The variability may also be described by a log-normal process with a median unabsorbed 2-8 keV flux of 1.8 −0.6 +0.8 ×10 −14  erg s –1  cm –2 and a shape parameter σ = 2.4 ± 0.2, but the power law provides a superior description of the data. In this decomposition of the flux distribution, all of the intrinsic X-ray variability of Sgr A* (spanning at least three orders of magnitude in flux) can be attributed to flaring activity, likely in the inner accretion flow. We confirm that at the faint end, the variable component contributes ∼10% of the apparent quiescent flux, as previously indicated by our statistical analysis of X-ray flares in these Chandra observations. Our flux distribution provides a new and important observational constraint on theoretical models of Sgr A*, and we use simple radiation models to explore the extent to which a statistical comparison of the X-ray and infrared can provide insights into the physics of the X-ray emission mechanism

  19. THE X-RAY FLUX DISTRIBUTION OF SAGITTARIUS A* AS SEEN BY CHANDRA

    Energy Technology Data Exchange (ETDEWEB)

    Neilsen, J. [Department of Astronomy, Boston University, Boston, MA 02215 (United States); Markoff, S. [Astronomical Institute, " Anton Pannekoek," University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Nowak, M. A.; Baganoff, F. K. [MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Dexter, J. [Department of Astronomy, Hearst Field Annex, University of California, Berkeley, CA 94720-3411 (United States); Witzel, G. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Barrière, N. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Li, Y. [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China); Degenaar, N. [Institute of Astronomy, University of Cambridge, Cambridge, CB3 OHA (United Kingdom); Fragile, P. C. [Department of Physics and Astronomy, College of Charleston, Charleston, SC 29424 (United States); Gammie, C. [Department of Astronomy, University of Illinois Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Goldwurm, A. [AstroParticule et Cosmologie (APC), Université Paris 7 Denis Diderot, F-75205 Paris cedex 13 (France); Grosso, N. [Observatoire Astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l' Université, F-67000 Strasbourg (France); Haggard, D., E-mail: jneilsen@space.mit.edu [Department of Physics and Astronomy, AC# 2244, Amherst College, Amherst, MA 01002 (United States)

    2015-02-01

    We present a statistical analysis of the X-ray flux distribution of Sgr A* from the Chandra X-Ray Observatory's 3 Ms Sgr A* X-ray Visionary Project in 2012. Our analysis indicates that the observed X-ray flux distribution can be decomposed into a steady quiescent component, represented by a Poisson process with rate Q = (5.24 ± 0.08) × 10{sup –3} counts s{sup –1}, and a variable component, represented by a power law process (dN/dF∝F {sup –ξ}, ξ=1.92{sub −0.02}{sup +0.03}). This slope matches our recently reported distribution of flare luminosities. The variability may also be described by a log-normal process with a median unabsorbed 2-8 keV flux of 1.8{sub −0.6}{sup +0.8}×10{sup −14} erg s{sup –1} cm{sup –2} and a shape parameter σ = 2.4 ± 0.2, but the power law provides a superior description of the data. In this decomposition of the flux distribution, all of the intrinsic X-ray variability of Sgr A* (spanning at least three orders of magnitude in flux) can be attributed to flaring activity, likely in the inner accretion flow. We confirm that at the faint end, the variable component contributes ∼10% of the apparent quiescent flux, as previously indicated by our statistical analysis of X-ray flares in these Chandra observations. Our flux distribution provides a new and important observational constraint on theoretical models of Sgr A*, and we use simple radiation models to explore the extent to which a statistical comparison of the X-ray and infrared can provide insights into the physics of the X-ray emission mechanism.

  20. CHANDRA OBSERVATIONS OF 3C RADIO SOURCES WITH z < 0.3. II. COMPLETING THE SNAPSHOT SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F. [SLAC National Laboratory and Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Tremblay, G. R. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Muenchen (Germany); Harris, D. E.; O' Dea, C. P. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Kharb, P.; Axon, D. [Department of Physics, Rochester Institute of Technology, Carlson Center for Imaging Science 76-3144, 84 Lomb Memorial Dr., Rochester, NY 14623 (United States); Balmaverde, B.; Capetti, A. [INAF-Osservatorio Astrofisico di Torino, Strada Osservatorio 20, I-10025 Pino Torinese (Italy); Baum, S. A. [Carlson Center for Imaging Science 76-3144, 84 Lomb Memorial Dr., Rochester, NY 14623 (United States); Chiaberge, M.; Macchetto, F. D.; Sparks, W. [Space Telescope Science Institute, 3700 San Martine Drive, Baltimore, MD 21218 (United States); Gilli, R. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Giovannini, G. [INAF-Istituto di Radioastronomia di Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Grandi, P.; Torresi, E. [INAF-IASF-Istituto di Astrofisica Spaziale e fisica Cosmica di Bologna, Via P. Gobetti 101, I-40129 Bologna (Italy); Risaliti, G. [INAF-Osservatorio Astronomico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)

    2012-12-15

    We report on the second round of Chandra observations of the 3C snapshot survey developed to observe the complete sample of 3C radio sources with z < 0.3 for 8 ks each. In the first paper, we illustrated the basic data reduction and analysis procedures performed for the 30 sources of the 3C sample observed during Chandra Cycle 9, while here we present the data for the remaining 27 sources observed during Cycle 12. We measured the X-ray intensity of the nuclei and of any radio hot spots and jet features with associated X-ray emission. X-ray fluxes in three energy bands, i.e., soft, medium, and hard, for all the sources analyzed are also reported. For the stronger nuclei, we also applied the standard spectral analysis, which provides the best-fit values of the X-ray spectral index and absorbing column density. In addition, a detailed analysis of bright X-ray nuclei that could be affected by pile-up has been performed. X-ray emission was detected for all the nuclei of the radio sources in our sample except for 3C 319. Among the current sample, there are two compact steep spectrum radio sources, two broad-line radio galaxies, and one wide angle tail radio galaxy, 3C 89, hosted in a cluster of galaxies clearly visible in our Chandra snapshot observation. In addition, we also detected soft X-ray emission arising from the galaxy cluster surrounding 3C 196.1. Finally, X-ray emission from hot spots has been found in three FR II radio sources and, in the case of 3C 459, we also report the detection of X-ray emission associated with the eastern radio lobe as well as X-ray emission cospatial with radio jets in 3C 29 and 3C 402.

  1. Chandra X-ray observations of the hyper-luminous infrared galaxy IRAS F15307+3252

    Science.gov (United States)

    Hlavacek-Larrondo, J.; Gandhi, P.; Hogan, M. T.; Gendron-Marsolais, M.-L.; Edge, A. C.; Fabian, A. C.; Russell, H. R.; Iwasawa, K.; Mezcua, M.

    2017-01-01

    Hyper-luminous infrared galaxies (HyLIRGs) lie at the extreme luminosity end of the IR galaxy population with LIR > 1013 L⊙. They are thought to be closer counterparts of the more distant sub-millimeter galaxies, and should therefore be optimal targets to study the most massive systems in formation. We present deep Chandra observations of IRAS F15307+3252 (100 ks), a classical HyLIRG located at z = 0.93 and hosting a radio-loud AGN (L1.4 GHz ˜ 3.5 × 1025 W Hz-1). The Chandra images reveal the presence of extended (r = 160 kpc), asymmetric X-ray emission in the soft 0.3-2.0 keV band that has no radio counterpart. We therefore argue that the emission is of thermal origin originating from a hot intragroup or intracluster medium virializing in the potential. We find that the temperature (˜2 keV) and bolometric X-ray luminosity (˜3 × 1043 erg s-1) of the gas follow the expected LX-ray-T correlation for groups and clusters, and that the gas has a remarkably short cooling time of 1.2 Gyr. In addition, VLA radio observations reveal that the galaxy hosts an unresolved compact steep-spectrum (CSS) source, most likely indicating the presence of a young radio source similar to 3C186. We also confirm that the nucleus is dominated by a redshifted 6.4 keV Fe Kα line, strongly suggesting that the AGN is Compton-thick. Finally, Hubble images reveal an overdensity of galaxies and sub-structure in the galaxy that correlates with soft X-ray emission. This could be a snapshot view of on-going groupings expected in a growing cluster environment. IRAS F15307+3252 might therefore be a rare example of a group in the process of transforming into a cluster.

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

    Science.gov (United States)

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

    2018-04-01

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

  3. The Chandra Source Catalog: Processing and Infrastructure

    Science.gov (United States)

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

    2009-09-01

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

  4. Optical and X-ray studies of Compact X-ray Binaries in NGC 5904

    Science.gov (United States)

    Bhalotia, Vanshree; Beck-Winchatz, Bernhard

    2018-06-01

    Due to their high stellar densities, globular cluster systems trigger various dynamical interactions, such as the formation of compact X-ray binaries. Stellar collisional frequencies have been correlated to the number of X-ray sources detected in various clusters and we hope to measure this correlation for NGC 5904. Optical fluxes of sources from archival HST images of NGC 5904 have been measured using a DOLPHOT PSF photometry in the UV, optical and near-infrared. We developed a data analysis pipeline to process the fluxes of tens of thousands of objects using awk, python and DOLPHOT. We plot color magnitude diagrams in different photometric bands in order to identify outliers that could be X-ray binaries, since they do not evolve the same way as singular stars. Aligning previously measured astrometric data for X-ray sources in NGC 5904 from Chandra with archival astrometric data from HST will filter out the outlier objects that are not X-ray producing, and provide a sample of compact binary systems that are responsible for X-ray emission in NGC 5904. Furthermore, previously measured X-ray fluxes of NGC 5904 from Chandra have also been used to measure the X-ray to optical flux ratio and identify the types of compact X-ray binaries responsible for the X-ray emissions in NGC 5904. We gratefully acknowledge the support from the Illinois Space Grant Consortium.

  5. The Chandra Source Catalog: Source Variability

    Science.gov (United States)

    Nowak, Michael; Rots, A. H.; McCollough, M. L.; Primini, F. A.; Glotfelty, K. J.; Bonaventura, N. R.; Chen, J. C.; Davis, J. E.; Doe, S. M.; Evans, J. D.; Evans, I.; Fabbiano, G.; Galle, E. C.; Gibbs, D. G., II; Grier, J. D.; Hain, R.; Hall, D. M.; Harbo, P. N.; He, X.; Houck, J. C.; Karovska, M.; Lauer, J.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Plummer, D. A.; Refsdal, B. L.; Siemiginowska, A. L.; Sundheim, B. A.; Tibbetts, M. S.; van Stone, D. W.; Winkelman, S. L.; Zografou, P.

    2009-09-01

    The Chandra Source Catalog (CSC) contains fields of view that have been studied with individual, uninterrupted observations that span integration times ranging from 1 ksec to 160 ksec, and a large number of which have received (multiple) repeat observations days to years later. The CSC thus offers an unprecedented look at the variability of the X-ray sky over a broad range of time scales, and across a wide diversity of variable X-ray sources: stars in the local galactic neighborhood, galactic and extragalactic X-ray binaries, Active Galactic Nuclei, etc. Here we describe the methods used to identify and quantify source variability within a single observation, and the methods used to assess the variability of a source when detected in multiple, individual observations. Three tests are used to detect source variability within a single observation: the Kolmogorov-Smirnov test and its variant, the Kuiper test, and a Bayesian approach originally suggested by Gregory and Loredo. The latter test not only provides an indicator of variability, but is also used to create a best estimate of the variable lightcurve shape. We assess the performance of these tests via simulation of statistically stationary, variable processes with arbitrary input power spectral densities (here we concentrate on results of red noise simulations) at variety of mean count rates and fractional root mean square variabilities relevant to CSC sources. We also assess the false positive rate via simulations of constant sources whose sole source of fluctuation is Poisson noise. We compare these simulations to an assessment of the variability found in real CSC sources, and estimate the variability sensitivities of the CSC.

  6. Chandra observations of Jupiter's X-ray Aurora during Juno upstream and apojove intervals

    Science.gov (United States)

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

    2017-12-01

    The Chandra space telescope has recently conducted a number of campaigns to observe Jupiter's X-ray aurora. The first set of campaigns took place in summer 2016 while the Juno spacecraft was upstream of the planet sampling the solar wind. The second set of campaigns took place in February, June and August 2017 at times when the Juno spacecraft was at apojove. These campaigns were planned following the Juno orbit correction to capitalise on the opportunity to image the X-ray emission while Juno was orbiting close to the expected position of the magnetopause. Previous work has suggested that the auroral X-ray emissions map close to the magnetopause boundary [e.g. Vogt et al., 2015; Kimura et al., 2016; Dunn et al., 2016] and thus in situ spacecraft coverage in this region combined with remote observation of the X-rays afford the chance to constrain the drivers of these energetic emissions and determine if they originate on open or closed field lines. We aim to examine possible drivers of X-ray emission including reconnection and the Kelvin-Helmholtz instability and to explore the role of the solar wind in controlling the emissions. We report on these upstream and apojove campaigns including intensities and periodicities of auroral X-ray emissions. This new era of jovian X-ray astronomy means we have more data than ever before, long observing windows (up to 72 ks for this Chandra set), and successive observations relatively closely spaced in time. These features combine to allow us to pursue novel methods for examining periodicities in the X-ray emission. Our work will explore significance testing of emerging periodicities, and the search for coherence in X-ray pulsing over weeks and months, seeking to understand the robustness and regularity of previously reported hot spot X-ray emissions. The periods that emerge from our analysis will be compared against those which emerge from radio and UV wavelengths.

  7. The Chandra Source Catalog 2.0: Spectral Properties

    Science.gov (United States)

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

    2018-01-01

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

  8. The First Chandra Field

    Energy Technology Data Exchange (ETDEWEB)

    Weisskopf, Martin C.; /NASA, Marshall; Aldcroft, Thomas L.; /Harvard-Smithsonian Ctr. Astrophys.; Cameron, Robert A.; /Harvard-Smithsonian Ctr. Astrophys. /SLAC; Gandhi,; Foellmi, Cedric; /European Southern Obs., Chile; Elsner, Ronald F.; /NASA, Marshall; Patel, Sandeep K.; /USRA, Huntsville; Wu, Kinwah; /Mullard Space Sci. Lab.; O' Dell, Stephen; /NASA, Marshall

    2005-09-09

    Before the official first-light images, the Chandra X-ray Observatory obtained an X-ray image of the field to which its focal plane was first exposed. We describe this historic observation and report our study of the first Chandra field. Chandra's Advanced CCD Imaging Spectrometer (ACIS) detected 15 X-ray sources, the brightest being dubbed ''Leon X-1'' to honor the Chandra Telescope Scientist, Leon Van Speybroeck. Based upon our analysis of the X-ray data and spectroscopy at the European Southern Observatory (ESO; La Silla, Chile), we find that Leon X-1 is a Type-1 (unobscured) active galactic nucleus (AGN) at a redshift z = 0.3207. Leon X-1 exhibits strong Fe II emission and a broad-line Balmer decrement that is unusually flat for an AGN. Within the context of the Eigenvector-1 correlation space, these properties suggest that Leon X-1 may be a massive ({ge} 10{sup 9} M{sub {circle_dot}}) black hole, accreting at a rate approaching its Eddington limit.

  9. The software development process at the Chandra X-ray Center

    Science.gov (United States)

    Evans, Janet D.; Evans, Ian N.; Fabbiano, Giuseppina

    2008-08-01

    Software development for the Chandra X-ray Center Data System began in the mid 1990's, and the waterfall model of development was mandated by our documents. Although we initially tried this approach, we found that a process with elements of the spiral model worked better in our science-based environment. High-level science requirements are usually established by scientists, and provided to the software development group. We follow with review and refinement of those requirements prior to the design phase. Design reviews are conducted for substantial projects within the development team, and include scientists whenever appropriate. Development follows agreed upon schedules that include several internal releases of the task before completion. Feedback from science testing early in the process helps to identify and resolve misunderstandings present in the detailed requirements, and allows review of intangible requirements. The development process includes specific testing of requirements, developer and user documentation, and support after deployment to operations or to users. We discuss the process we follow at the Chandra X-ray Center (CXC) to develop software and support operations. We review the role of the science and development staff from conception to release of software, and some lessons learned from managing CXC software development for over a decade.

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

    International Nuclear Information System (INIS)

    Hou, Meicun; Li, Zhiyuan

    2016-01-01

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

  11. 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.

  12. DIFFERENT TYPES OF ULTRALUMINOUS X-RAY SOURCES IN NGC 4631

    International Nuclear Information System (INIS)

    Soria, Roberto; Ghosh, Kajal K.

    2009-01-01

    We have re-examined the most luminous X-ray sources in the starburst galaxy NGC 4631, using XMM-Newton, Chandra, and ROSAT data. The most interesting source is a highly variable supersoft ultraluminous X-ray source (ULX). We suggest that its bolometric luminosity ∼ a few 10 39 erg s -1 in the high/supersoft state: this is an order of magnitude lower than estimated in previous studies, thus reducing the need for extreme or exotic scenarios. Moreover, we find that this source was in a noncanonical low/soft (kT ∼ 0.1-0.3 keV) state during the Chandra observation. By comparing the high and low state, we argue that the spectral properties may not be consistent with the expected behavior of an accreting intermediate-mass black hole. We suggest that recurrent super-Eddington outbursts with photospheric expansion from a massive white dwarf (M wd ∼> 1.3 M sun ), powered by nonsteady nuclear burning, may be a viable possibility, in alternative to the previously proposed scenario of a super-Eddington outflow from an accreting stellar-mass black hole. The long-term average accretion rate required for nuclear burning to power such white-dwarf outbursts in this source and perhaps in other supersoft ULXs is ∼(5-10) x 10 -6 M sun yr -1 : this is comparable to the thermal-timescale mass transfer rate invoked to explain the most luminous hard-spectrum ULXs (powered by black hole accretion). The other four most luminous X-ray sources in NGC 4631 (three of which can be classified as ULXs) appear to be typical accreting black holes, in four different spectral states: high/soft, convex-spectrum, power-law with soft excess, and simple power-law. None of them require masses ∼>50 M sun .

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

    Science.gov (United States)

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

    2017-05-01

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

  14. The galactic luminous supersoft X-ray source RXJ0925.7-4758 / MR ...

    Indian Academy of Sciences (India)

    Nandita Prodhani

    2018-01-30

    Jan 30, 2018 ... White dwarf; luminous supersoft X-ray source; luminosity; absorption edge. PACS Nos 97.80.Jp; 97.10.Ri; 98.35.Mp; 97.80.Fk. 1. Introduction. For the last few decades, Einstein observatory, Roent- gen Satellite (ROSAT), ASCA, CHANDRA, XMM-. Newton, SWIFT, SUZAKU and other ingenious devices.

  15. Environments of High Luminosity X-Ray Sources in the Antennae Galaxies

    Science.gov (United States)

    Clark, D. M.; Eikenberry, S. S.; Brandl, B. R.; Wilson, J. C.; Carson, J. C.; Henderson, C. P.; Hayward, T. P.; Barry, D. J.; Houck, J. R.; Ptak, A.; Colbert, E.

    2003-12-01

    We use deep J (1.25 μ m) and Ks (2.15 μ m) images of the Antennae (NGC 4038/9) obtained with the Wide-field InfraRed Camera on the Palomar 200-inch telescope, together with the Chandra X-ray source list of Zezas et al. (2001), to establish an X-ray/IR astrometric frame tie with ˜ 0.5 ″ RMS residuals over a ˜ 5 ‧ field. We find 13 ``strong" IR counterparts 99.9% confidence), and that the X-ray/IR matches are concentrated in the spiral arms and ``bridge" regions of the Antennae. This implies that these X-ray sources lie in the most ``super" of the Antennae's Super Star Clusters, and thus trace the recent massive star formation history here. Based on the NH inferred from the X-ray sources without IR counterparts, we determine that the absence of most of the ``missing" IR counterparts is not due to extinction, but that these sources are intrinsically less luminous in the IR, implying that they trace a different (older?) stellar population. We find no clear correlation between X-ray luminosity classes and IR properties of the sources, though small number statistics hamper this analysis. Finally, we find a Ks = 16.2 mag counterpart to the Ultra-Luminous X-ray (ULX) source X-37 within <0.5 ″ , eliminating the need for the ``runaway binary" hypothesis proposed by previous authors for this object. We discuss some of the implications of this detection for models of ULX emission. This work is funded by an NSF CAREER grant.

  16. The radio-X-ray relation as a star formation indicator: results from the Very Large Array-Extended Chandra Deep Field-South

    Science.gov (United States)

    Vattakunnel, S.; Tozzi, P.; Matteucci, F.; Padovani, P.; Miller, N.; Bonzini, M.; Mainieri, V.; Paolillo, M.; Vincoletto, L.; Brandt, W. N.; Luo, B.; Kellermann, K. I.; Xue, Y. Q.

    2012-03-01

    In order to trace the instantaneous star formation rate (SFR) at high redshift, and thus help in understanding the relation between the different emission mechanisms related to star formation, we combine the recent 4-Ms Chandra X-ray data and the deep Very Large Array radio data in the Extended Chandra Deep Field-South region. We find 268 sources detected both in the X-ray and radio bands. The availability of redshifts for ˜95 per cent of the sources in our sample allows us to derive reliable luminosity estimates and the intrinsic properties from X-ray analysis for the majority of the objects. With the aim of selecting sources powered by star formation in both bands, we adopt classification criteria based on X-ray and radio data, exploiting the X-ray spectral features and time variability, taking advantage of observations scattered across more than 10 years. We identify 43 objects consistent with being powered by star formation. We also add another 111 and 70 star-forming candidates detected only in the radio and X-ray bands, respectively. We find a clear linear correlation between radio and X-ray luminosity in star-forming galaxies over three orders of magnitude and up to z˜ 1.5. We also measure a significant scatter of the order of 0.4 dex, higher than that observed at low redshift, implying an intrinsic scatter component. The correlation is consistent with that measured locally, and no evolution with redshift is observed. Using a locally calibrated relation between the SFR and the radio luminosity, we investigate the LX(2-10 keV)-SFR relation at high redshift. The comparison of the SFR measured in our sample with some theoretical models for the Milky Way and M31, two typical spiral galaxies, indicates that, with current data, we can trace typical spirals only at z≤ 0.2, and strong starburst galaxies with SFRs as high as ˜100 M⊙ yr-1, up to z˜ 1.5.

  17. VizieR Online Data Catalog: Intermediate-luminosity X-ray objects catalog (Colbert+, 2002)

    Science.gov (United States)

    Colbert, E. J. M.; Ptak, A. F.

    2002-11-01

    ROSAT, and now Chandra, X-ray images allow studies of extranuclear X-ray point sources in galaxies other than our own. X-ray observations of normal galaxies with ROSAT and Chandra have revealed that off-nuclear, compact, intermediate-luminosity (LX[2-10keV]>=1039erg/s) X-ray objects (IXOs, a.k.a. ULXs [ultraluminous X-ray sources]) are quite common. Here we present a catalog and finding charts for 87 IXOs in 54 galaxies, derived from all of the ROSAT HRI imaging data for galaxies with cz<=5000km/s from the Third Reference Catalog of Bright Galaxies. (2 data files).

  18. 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.

  19. Most powerful X-ray telescope marks third anniversary

    Science.gov (United States)

    2002-08-01

    A black hole gobbles up matter in our own Milky Way Galaxy. A hot spot of X-rays pulsates from near Jupiter's poles. An intergalactic web of hot gas, hidden from view since the time galaxies formed, is finally revealed. These scenarios sound like science fiction - but to those familiar with the latest developments in X-ray astronomy, they are just a few of the real-life discoveries made by NASA's Chandra X-ray Observatory during its third year of operation. "Within the last year, Chandra has revealed another series of never-before-seen phenomena in our galaxy and beyond," said Chandra project scientist Dr. Martin Weisskopf of NASA's Marshall Space Flight Center in Huntsville, Ala. "When you combine recent discoveries with the secrets revealed during the observatory's first two years in orbit, it's amazing how much Chandra has told us about the universe in a relatively short period of time." One such discovery was an unprecedented view of a supermassive black hole devouring material in the Milky Way Galaxy - a spectacle witnessed for the first time when Chandra observed a rapid X-ray flare emitted from the direction of the black hole residing at our galaxy's center. In a just few minutes, Sagittarius A, a source of radio emission believed to be associated with the black hole, became 45 times brighter in X-rays, before declining to pre-flare levels a few hours later, offering astronomers a never-before-seen view of the energetic processes surrounding this supermassive black hole. "When we launched the Chandra Observatory, we attempted to explain its amazing capabilities in Earthly terms, such as the fact it can 'see' so well, it's like someone reading the letters of a stop sign 12 miles away," said Chandra Program Manager Tony Lavoie of the Marshall Center. "But now that the observatory has been in orbit for three years, we have unearthly proof of the technological marvel Chandra really is. Not only has it continued to operate smoothly and efficiently, it has

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

    Science.gov (United States)

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

    2017-10-01

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

  1. NARROW-LINE X-RAY-SELECTED GALAXIES IN THE CHANDRA -COSMOS FIELD. I. OPTICAL SPECTROSCOPIC CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Pons, E.; Watson, M. G. [University of Leicester, Leicester (United Kingdom); Elvis, M.; Civano, F. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

    2016-04-20

    The COSMOS survey is a large and deep survey with multiwavelength observations of sources from X-rays to the UV, allowing an extensive study of their properties. The central 0.9 deg{sup 2} of the COSMOS field have been observed by Chandra with a sensitivity up to 1.9 × 10{sup −16} erg cm{sup −2} s{sup −1} in the full (0.5–10 keV) band. Photometric and spectroscopic identification of the Chandra -COSMOS (C-COSMOS) sources is available from several catalogs and campaigns. Despite the fact that the C-COSMOS galaxies have a reliable spectroscopic redshift in addition to a spectroscopic classification, the emission-line properties of this sample have not yet been measured. We present here the creation of an emission-line catalog of 453 narrow-line sources from the C-COSMOS spectroscopic sample. We have performed spectral fitting for the more common lines in galaxies ([O ii] λ 3727, [Ne iii] λ 3869, H β , [O iii] λλ 4959, 5007, H α , and [N ii] λλ 6548, 6584). These data provide an optical classification for 151 (i.e., 33%) of the C-COSMOS narrow-line galaxies based on emission-line diagnostic diagrams.

  2. New insights into the X-ray properties of nearby barred spiral galaxy NGC 1672

    Science.gov (United States)

    Jenkins, L. P.; Brnadt, W. N.; Colbert, E. J. M.; Levan, A. J.; Roberts, T. P.; Ward, M. J.; Zezas, A.

    2008-02-01

    We present some preliminary results from new Chandra and XMM-Newton X-ray observations of the nearby barred spiral galaxy NGC1672. It shows dramatic nuclear and extra-nuclear star formation activity, including starburst regions located near each end of its strong bar, both of which host ultraluminous X-ray sources (ULXs). With the new high-spatial-resolution Chandra imaging, we show for the first time that NGC1672 possesses a faint ($L(X)~10^39 erg/s), hard central X-ray source surrounded by an X-ray bright circumnuclear starburst ring that dominates the X-ray emission in the region. The central source may represent low-level AGN activity, or alternatively the emission from X-ray binaries associated with star-formation in the nucleus.

  3. The Chandra Source Catalog 2.0: Building The Catalog

    Science.gov (United States)

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

    2018-01-01

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

  4. Uncovering extreme AGN variability in serendipitous X-ray source surveys

    Science.gov (United States)

    Moran, Edward C.; Garcia Soto, Aylin; LaMassa, Stephanie; Urry, Meg

    2018-01-01

    Constraints on the duty cycle and duration of accretion episodes in active galactic nuclei (AGNs) are vital for establishing how most AGNs are fueled, which is essential for a complete picture of black hole/galaxy co-evolution. Perhaps the best handle we have on these activity parameters is provided by AGNs that have displayed dramatic changes in their bolometric luminosities and, in some cases, spectroscopic classifications. Given that X-ray emission is directly linked to black-hole accretion, X-ray surveys should provide a straightforward means of identifying AGNs that have undergone dramatic changes in their accretion states. However, it appears that such events are very rare, so wide-area surveys separated in time by many years are needed to maximize discovery rates. We have cross-correlated the Einstein IPC Two-Sigma Catalog with the ROSAT All-Sky Survey Faint Source Catalog to identify a sample of soft X-ray sources that varied by factors ranging from 7 to more than 100 over a ten year timescale. When possible, we have constructed long-term X-ray light curves for the sources by combining the Einstein and RASS fluxes with those obtained from serendipitous pointed observations by ROSAT, Chandra,XMM, and Swift. Optical follow-up observations indicate that many of the extremely variable sources in our sample are indeed radio-quiet AGNs. Interestingly, the majority of objects that dimmed between ~1980 and ~1990 are still (or are again) broad-line AGNs rather than“changing-look” candidates that have more subtle AGN signatures in their spectra — despite the fact that none of the sources examined thus far has returned to its highest observed luminosity. Future X-ray observations will provide the opportunity to characterize the X-ray behavior of these anonymous, extreme AGNs over a four decade span.

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

    Science.gov (United States)

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

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

  6. THE IDENTIFICATION OF THE X-RAY COUNTERPART TO PSR J2021+4026

    Energy Technology Data Exchange (ETDEWEB)

    Weisskopf, Martin C.; Elsner, Ronald F.; O' Dell, Stephen L.; Tennant, Allyn F. [NASA Marshall Space Flight Center, Space Science Office, VP62, Huntsville, AL 35812 (United States); Romani, Roger W. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Razzano, Massimiliano [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Belfiore, Andrea; Saz Parkinson, Pablo; Ziegler, Marcus; Dormody, Michael [Santa Cruz Institute for Particle Physics, Department of Physics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Ray, Paul S. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Kerr, Matthew [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305 (United States); Harding, Alice [Astrophysics Science Division, NASA Goddard Space Flight Center, Code 663, Greenbelt, MD 20771 (United States); Swartz, Douglas A. [Universities Space Research Association, NASA Marshall Space Flight Center, Space Science Office, VP62, Huntsville, AL 35812 (United States); Carraminana, Alberto [Instituto Nacional de Astrofisica, Optica y Electronica, Luis Enrique Erro 1, Tonantzintla, Puebla 72840 (Mexico); Becker, Werner; Kanbach, Gottfried [Max-Planck-Institut fuer extraterrestrische Physik, 85741 Garching bei Muenchen (Germany); De Luca, Andrea [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, I-20133 Milano (Italy); Thompson, David J. [Astroparticle Physics Laboratory, NASA Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States)

    2011-12-10

    We report the probable identification of the X-ray counterpart to the {gamma}-ray pulsar PSR J2021+4026 using imaging with the Chandra X-ray Observatory Advanced CCD Imaging Spectrometer and timing analysis with the Fermi satellite. Given the statistical and systematic errors, the positions determined by both satellites are coincident. The X-ray source position is R.A. 20{sup h}21{sup m}30.{sup s}733, decl. +40 Degree-Sign 26'46.''04 (J2000) with an estimated uncertainty of 1.''3 combined statistical and systematic error. Moreover, both the X-ray to {gamma}-ray and the X-ray to optical flux ratios are sensible assuming a neutron star origin for the X-ray flux. The X-ray source has no cataloged infrared-to-visible counterpart and, through new observations, we set upper limits to its optical emission of i' > 23.0 mag and r' > 25.2 mag. The source exhibits an X-ray spectrum with most likely both a power law and a thermal component. We also report on the X-ray and visible light properties of the 43 other sources detected in our Chandra observation.

  7. THE IDENTIFICATION OF THE X-RAY COUNTERPART TO PSR J2021+4026

    International Nuclear Information System (INIS)

    Weisskopf, Martin C.; Elsner, Ronald F.; O'Dell, Stephen L.; Tennant, Allyn F.; Romani, Roger W.; Razzano, Massimiliano; Belfiore, Andrea; Saz Parkinson, Pablo; Ziegler, Marcus; Dormody, Michael; Ray, Paul S.; Kerr, Matthew; Harding, Alice; Swartz, Douglas A.; Carramiñana, Alberto; Becker, Werner; Kanbach, Gottfried; De Luca, Andrea; Thompson, David J.

    2011-01-01

    We report the probable identification of the X-ray counterpart to the γ-ray pulsar PSR J2021+4026 using imaging with the Chandra X-ray Observatory Advanced CCD Imaging Spectrometer and timing analysis with the Fermi satellite. Given the statistical and systematic errors, the positions determined by both satellites are coincident. The X-ray source position is R.A. 20 h 21 m 30. s 733, decl. +40°26'46.''04 (J2000) with an estimated uncertainty of 1.''3 combined statistical and systematic error. Moreover, both the X-ray to γ-ray and the X-ray to optical flux ratios are sensible assuming a neutron star origin for the X-ray flux. The X-ray source has no cataloged infrared-to-visible counterpart and, through new observations, we set upper limits to its optical emission of i' > 23.0 mag and r' > 25.2 mag. The source exhibits an X-ray spectrum with most likely both a power law and a thermal component. We also report on the X-ray and visible light properties of the 43 other sources detected in our Chandra observation.

  8. Matching microlensing events with X-ray sources

    Science.gov (United States)

    Sartore, N.; Treves, A.

    2012-03-01

    Aims: The detection of old neutron stars and stellar mass black holes in isolation is one of the most sought after goals of compact object astrophysics. Microlensing surveys may help in achieving this aim because the lensing mechanism is independent of the emission properties of the lens. Several black hole candidates have indeed been detected by means of 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. Methods: We perform a cross-correlation between the catalogs of microlensing events produced by the OGLE, MACHO, and MOA teams, and those of X-rays sources from the data acquired by the XMM-Newton and Chandra satellites. On the basis of our previous work, we select only microlensing events with durations longer than one hundred days, which should contain a large fraction of lenses as compact objects. Our matching criterion takes into account the positional coincidence on the sky. Results: We find a single match between a microlensing event, OGLE-2004-BLG-081 (tE ~ 103 days), and the X-ray source 2XMM J180540.5-273427. The angular separation is ~0.5 arcsec, i.e. well within the 90% error box of the X-ray source. The hardness ratios reported in the 2XMM catalog imply that it has a hard spectrum with a peak between 2 keV and 4.5 keV or it has a softer but highly absorbed spectrum. Moreover, the microlensing event is not fully constrained, and other authors propose a possible association of the source star with either a flaring cataclysmic variable or a RS Canum Venaticorum-like star. Conclusions: The very small angular separation (within uncertainties) is a strong indicator that 2XMM J180540.5-273427 is the X-ray counterpart of the OGLE event. However, the uncertainties in the nature of both the lensed system and the lens itself challenge the interpretation of 2XMM J180540.5-273427 as the first confirmed isolated black

  9. M31 in the Chandra Era: A High Definition Movie of a Nearby Galaxy

    Science.gov (United States)

    Kong, Albert; di Stefano, Rosanne

    2009-09-01

    M31 has been a prime targets for all X-ray missions since the first detection in 1974. With its superb spatial resolution, Chandra is unique in resolving dense source regions and detecting faint sources. Since the launch of Chandra, M31 has been regularly observed. It is perhaps the only nearby galaxy which is observed by an X-ray telescope regularly throughout operation. With 10 years of observations, the center of M31 has been observed with Chandra for nearly 1 Msec. The X-ray skies of M31 not only consist of many transients and variables, globular cluster X-ray sources in M31 are also different from our Milky Way. They are in general more luminous and one of them may even host an intermediate-mass black hole. Supersoft and quasi-soft X-ray sources in M31 are the best kept secret to unlock the nature of the progenitor of Type Ia supernova. In this talk, I will review some of the important Chandra discoveries in M31 in the past 10 years.

  10. 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.

  11. Probing the Spatial Distribution of the Interstellar Dust Medium by High Angular Resolution X-ray Halos of Point Sources

    Science.gov (United States)

    Xiang, Jingen

    X-rays are absorbed and scattered by dust grains when they travel through the interstellar medium. The scattering within small angles results in an X-ray ``halo''. The halo properties are significantly affected by the energy of radiation, the optical depth of the scattering, the grain size distributions and compositions, and the spatial distribution of dust along the line of sight (LOS). Therefore analyzing the X-ray halo properties is an important tool to study the size distribution and spatial distribution of interstellar grains, which plays a central role in the astrophysical study of the interstellar medium, such as the thermodynamics and chemistry of the gas and the dynamics of star formation. With excellent angular resolution, good energy resolution and broad energy band, the Chandra ACIS is so far the best instrument for studying the X-ray halos. But the direct images of bright sources obtained with ACIS usually suffer from severe pileup which prevents us from obtaining the halos in small angles. We first improve the method proposed by Yao et al to resolve the X-ray dust scattering halos of point sources from the zeroth order data in CC-mode or the first order data in TE mode with Chandra HETG/ACIS. Using this method we re-analyze the Cygnus X-1 data observed with Chandra. Then we studied the X-ray dust scattering halos around 17 bright X-ray point sources using Chandra data. All sources were observed with the HETG/ACIS in CC-mode or TE-mode. Using the interstellar grain models of WD01 model and MRN model to fit the halo profiles, we get the hydrogen column densities and the spatial distributions of the scattering dust grains along the line of sights (LOS) to these sources. We find there is a good linear correlation not only between the scattering hydrogen column density from WD01 model and the one from MRN model, but also between N_{H} derived from spectral fits and the one derived from the grain models WD01 and MRN (except for GX 301-2 and Vela X-1): N

  12. IDENTIFICATIONS AND PHOTOMETRIC REDSHIFTS OF THE 2 Ms CHANDRA DEEP FIELD-SOUTH SOURCES

    International Nuclear Information System (INIS)

    Luo, B.; Brandt, W. N.; Xue, Y. Q.; Rafferty, D. A.; Schneider, D. P.; Brusa, M.; Alexander, D. M.; Lehmer, B. D.; Bauer, F. E.; Comastri, A.; Koekemoer, A.; Mainieri, V.; Silverman, J. D.; Vignali, C.

    2010-01-01

    We present reliable multiwavelength identifications and high-quality photometric redshifts for the 462 X-ray sources in the ∼2 Ms Chandra Deep Field-South (CDF-S) survey. Source identifications are carried out using deep optical-to-radio multiwavelength catalogs, and are then combined to create lists of primary and secondary counterparts for the X-ray sources. We identified reliable counterparts for 442 (95.7%) of the X-ray sources, with an expected false-match probability of ∼ 6.2%; we also selected four additional likely counterparts. The majority of the other 16 X-ray sources appear to be off-nuclear sources, sources associated with galaxy groups and clusters, high-redshift active galactic nuclei (AGNs), or spurious X-ray sources. A likelihood-ratio method is used for source matching, which effectively reduces the false-match probability at faint magnitudes compared to a simple error-circle matching method. We construct a master photometric catalog for the identified X-ray sources including up to 42 bands of UV-to-infrared data, and then calculate their photometric redshifts (photo-z's). High accuracy in the derived photo-z's is accomplished owing to (1) the up-to-date photometric data covering the full spectral energy distributions (SEDs) of the X-ray sources, (2) more accurate photometric data as a result of source deblending for ∼10% of the sources in the infrared bands and a few percent in the optical and near-infrared bands, (3) a set of 265 galaxy, AGN, and galaxy/AGN hybrid templates carefully constructed to best represent all possible SEDs, (4) the Zurich Extragalactic Bayesian Redshift Analyzer used to derive the photo-z's, which corrects the SED templates to best represent the SEDs of real sources at different redshifts and thus improves the photo-z quality. The reliability of the photo-z's is evaluated using the subsample of 220 sources with secure spectroscopic redshifts. We achieve an accuracy of |Δz|/(1 + z) ∼ 1% and an outlier [with |

  13. A Catalog of Candidate Intermediate-Luminosity X-Ray Objects

    Science.gov (United States)

    Colbert, E. J. M.; Ptak, A. F.

    2002-11-01

    ROSAT, and now Chandra, X-ray images allow studies of extranuclear X-ray point sources in galaxies other than our own. X-ray observations of normal galaxies with ROSAT and Chandra have revealed that off-nuclear, compact, intermediate-luminosity (LX[2-10keV]>=1039.0 ergs s-1) X-ray objects (IXOs, a.k.a. ULXs [ultraluminous X-ray sources]) are quite common. Here we present a catalog and finding charts for 87 IXOs in 54 galaxies, derived from all of the ROSAT HRI imaging data for galaxies with cz<=5000 km s-1 from the Third Reference Catalog of Bright Galaxies. We have defined the cutoff LX for IXOs so that it is well above the Eddington luminosity of a 1.4 Msolar black hole (1038.3 ergs s-1), so as not to confuse IXOs with ``normal'' black hole X-ray binaries. This catalog is intended to provide a baseline for follow-up work with Chandra and XMM-Newton, and with space- and ground-based survey work at wavelengths other than X-ray. We demonstrate that elliptical galaxies with IXOs have a larger number of IXOs per galaxy than nonelliptical galaxies with IXOs and note that they are not likely to be merely high-mass X-ray binaries with beamed X-ray emission, as may be the case for IXOs in starburst galaxies. Approximately half of the IXOs with multiple observations show X-ray variability, and many (19) of the IXOs have faint optical counterparts in DSS optical B-band images. Follow-up observations of these objects should be helpful in identifying their nature.

  14. A Comparison Between Spectral Properties of ULXs and Luminous X-ray Binaries

    Science.gov (United States)

    Berghea, C. T.; Colbert, E. J. M.; Roberts, T. P.

    2004-05-01

    What is special about the 1039 erg s-1 limit that is used to define the ULX class? We investigate this question by analyzing Chandra X-ray spectra of 71 X-ray bright point sources from nearby galaxies. Fifty-one of these sources are ULXs (LX(0.3-8.0 keV) ≥ 1039 erg s-1), and 20 sources (our comparison sample) are less-luminous X-ray binaries with LX(0.3-8.0 keV) = 1038-39 erg s-1. Our sample objects were selected from the Chandra archive to have ≥1000 counts and thus represent the highest quality spectra in the Chandra archives for extragalactic X-ray binaries and ULXs. We fit the spectra with one-component models (e.g., cold absorption with power-law, or cold absorption with multi-colored disk blackbody) and two-component models (e.g. absorption with both a power-law and a multi colored disk blackbody). A crude measure of the spectral states of the sources are determined observationally by calibrating the strength of the disk (blackbody) and coronal (power-law) components. These results are then use to determine if spectral properties of the ULXs are statistically distinct from those of the comparison objects, which are assumed to be ``normal'' black-hole X-ray binaries.

  15. THE X-RAY HALO OF CEN X-3

    International Nuclear Information System (INIS)

    Thompson, Thomas W. J.; Rothschild, Richard E.

    2009-01-01

    Using two Chandra observations, we have derived estimates of the dust distribution and distance to the eclipsing high-mass X-ray binary Cen X-3 using the energy-resolved dust-scattered X-ray halo. By comparing the observed X-ray halos in 200 eV bands from 2-5 keV to the halo profiles predicted by the Weingartner and Draine interstellar grain model, we find that the vast majority (∼ 70%) of the dust along the line of sight to the system is located within about 300 pc of the Sun, although the halo measurements are insensitive to dust very close to the source. One of the Chandra observations occurred during an egress from eclipse as the pulsar emerged from behind the mass-donating primary. By comparing model halo light curves during this transition to the halo measurements, a source distance of 5.7 ± 1.5 kpc (68% confidence level) is estimated, although we find this result depends on the distribution of dust on very small scales. Nevertheless, this value is marginally inconsistent with the commonly accepted distance to Cen X-3 of 8 kpc. We also find that the energy scaling of the scattering optical depth predicted by the Weingartner and Draine interstellar grain model does not accurately represent the results determined by X-ray halo studies of Cen X-3. Relative to the model, there appears to be less scattering at low energies or more scattering at high energies in Cen X-3.

  16. Revealing the nature of the ULX and X-ray population of the spiral galaxy NGC 4088

    Energy Technology Data Exchange (ETDEWEB)

    Mezcua, M. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Fabbiano, G. [Harvard-Smithsonian Center for Astrophysics (CfA), 60 Garden Street, Cambridge, MA 02138 (United States); Gladstone, J. C. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Farrell, S. A. [Sydney Institute for Astronomy (SIfA), School of Physics, The University of Sydney, NSW 2006 (Australia); Soria, R., E-mail: mmezcua@iac.es [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia)

    2014-04-20

    We present the first Chandra and Swift X-ray study of the spiral galaxy NGC 4088 and its ultraluminous X-ray source (ULX N4088-X1). We also report very long baseline interferometry (VLBI) observations at 1.6 and 5 GHz performed quasi-simultaneously with the Swift and Chandra observations, respectively. Fifteen X-ray sources are detected by Chandra within the D25 ellipse of NGC 4088, from which we derive the X-ray luminosity function (XLF) of this galaxy. We find the XLF is very similar to those of star-forming galaxies and estimate a star-formation rate of 4.5 M {sub ☉} yr{sup –1}. The Chandra detection of the ULX yields its most accurate X-ray position, which is spatially coincident with compact radio emission at 1.6 GHz. The ULX Chandra X-ray luminosity, L {sub 0.2-10.0} {sub keV} = 3.4 × 10{sup 39} erg s{sup –1}, indicates that N4088-X1 could be located at the high-luminosity end of the high-mass X-ray binary (HMXB) population of NGC 4088. The estimates of the black hole (BH) mass and ratio of radio to X-ray luminosity of N4088-X1 rule out a supermassive BH nature. The Swift X-ray spectrum of N4088-X1 is best described by a thermal Comptonization model and presents a statistically significant high-energy cutoff. We conclude that N4088-X1 is most likely a stellar remnant BH in an HMXB, probably fed by Roche lobe overflow, residing in a super-Eddington ultraluminous state. The 1.6 GHz VLBI source is consistent with radio emission from possible ballistic jet ejections in this state.

  17. Chandra Sees Remarkable Eclipse of Black Hole

    Science.gov (United States)

    2007-04-01

    A remarkable eclipse of a supermassive black hole and the hot gas disk around it has been observed with NASA's Chandra X-ray Observatory. This eclipse has allowed two key predictions about the effects of supermassive black holes to be tested. Just as eclipses of the Sun and moon give astronomers rare opportunities to learn about those objects, an alignment in a nearby galaxy has provided a rare opportunity to investigate a supermassive black hole. Illustrations of Black Hole Eclipse Illustrations of Black Hole Eclipse The supermassive black hole is located in NGC 1365, a galaxy 60 million light years from Earth. It contains a so called active galactic nucleus, or AGN. Scientists believe that the black hole at the center of the AGN is fed by a steady stream of material, presumably in the form of a disk. Material just about to fall into a black hole should be heated to millions of degrees before passing over the event horizon, or point of no return. The disk of gas around the central black hole in NGC 1365 produces copious X-rays but is much too small to resolve directly with a telescope. However, the disk was eclipsed by an intervening cloud, so observation of the time taken for the disk to go in and out of eclipse allowed scientists to estimate the size of the disk. Black Hole Animation Black Hole Animation "For years we've been struggling to confirm the size of this X-ray structure," said Guido Risaliti of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass, and the Italian Institute of Astronomy (INAF). "This serendipitous eclipse enabled us to make this breakthrough." The Chandra team directly measured the size of the X-ray source as about seven times the distance between the Sun and the Earth. That means the source of X-rays is about 2 billion times smaller than the host galaxy and only about 10 times larger than the estimated size of the black hole's event horizon, consistent with theoretical predictions. Chandra X-ray Image of NGC 1365

  18. 12 YEARS OF X-RAY VARIABILITY IN M31 GLOBULAR CLUSTERS, INCLUDING 8 BLACK HOLE CANDIDATES, AS SEEN BY CHANDRA

    International Nuclear Information System (INIS)

    Barnard, R.; Garcia, M.; Murray, S. S.

    2012-01-01

    We examined 134 Chandra observations of the population of X-ray sources associated with globular clusters (GCs) in the central region of M31. These are expected to be X-ray binary systems (XBs), consisting of a neutron star or black hole accreting material from a close companion. We created long-term light curves for these sources, correcting for background, interstellar absorption, and instrumental effects. We tested for variability by examining the goodness of fit for the best-fit constant intensity. We also created structure functions (SFs) for every object in our sample, the first time this technique has been applied to XBs. We found significant variability in 28 out of 34 GCs and GC candidates; the other 6 sources had 0.3-10 keV luminosities fainter than ∼2 × 10 36 erg s –1 , limiting our ability to detect similar variability. The SFs of XBs with 0.3-10 keV luminosities ∼2-50 × 10 36 erg s –1 generally showed considerably more variability than the published ensemble SF of active galactic nuclei (AGNs). Our brightest XBs were mostly consistent with the AGN SF; however, their 2-10 keV fluxes could be matched by <1 AGN per square degree. These encouraging results suggest that examining the long-term light curves of other X-ray sources in the field may provide an important distinction between X-ray binaries and background galaxies, as the X-ray emission spectra from these two classes of X-ray sources are similar. Additionally, we identify 3 new black hole candidates (BHCs) using additional XMM-Newton data, bringing the total number of M31 GC BHCs to 9, with 8 covered in this survey.

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

    Science.gov (United States)

    Weisskopf, Martin C.

    2012-01-01

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

  20. Optics Developments for X-Ray Astronomy

    Science.gov (United States)

    Ramsey, Brian

    2014-01-01

    X-ray optics has revolutionized x-ray astronomy. The degree of background suppression that these afford, have led to a tremendous increase in sensitivity. The current Chandra observatory has the same collecting area (approx. 10(exp 3)sq cm) as the non-imaging UHURU observatory, the first x-ray observatory which launched in 1970, but has 5 orders of magnitude more sensitivity due to its focusing optics. In addition, its 0.5 arcsec angular resolution has revealed a wealth of structure in many cosmic x-ray sources. The Chandra observatory achieved its resolution by using relatively thick pieces of Zerodur glass, which were meticulously figured and polished to form the four-shell nested array. The resulting optical assembly weighed around 1600 kg, and cost approximately $0.5B. The challenge for future x-ray astronomy missions is to greatly increase the collecting area (by one or more orders of magnitude) while maintaining high angular resolution, and all within realistic mass and budget constraints. A review of the current status of US optics for x-ray astronomy will be provided along with the challenges for future developments.

  1. Monitoring Chandra Observations of the Quasi-persistent Neutron Star X-Ray Transient MXB 1659-29 in Quiescence: The Cooling Curve of the Heated Neutron Star Crust

    NARCIS (Netherlands)

    Wijnands, R.A.D.; Homan, J.; Miller, J.M.; Lewin, W.H.G.

    2004-01-01

    We have observed the quasi-persistent neutron star X-ray transient and eclipsing binary MXB 1659-29 in quiescence on three occasions with Chandra. The purpose of our observations was to monitor the quiescent behavior of the source after its last prolonged (~2.5 yr) outburst that ended in 2001

  2. 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.

  3. Identifications and Photometric Redshifts of the 2 Ms Chandra Deep Field-South Sources

    Science.gov (United States)

    Luo, B.; Brandt, W. N.; Xue, Y. Q.; Brusa, M.; Alexander, D. M.; Bauer, F. E.; Comastri, A.; Koekemoer, A.; Lehmer, B. D.; Mainieri, V.; Rafferty, D. A.; Schneider, D. P.; Silverman, J. D.; Vignali, C.

    2010-04-01

    We present reliable multiwavelength identifications and high-quality photometric redshifts for the 462 X-ray sources in the ≈2 Ms Chandra Deep Field-South (CDF-S) survey. Source identifications are carried out using deep optical-to-radio multiwavelength catalogs, and are then combined to create lists of primary and secondary counterparts for the X-ray sources. We identified reliable counterparts for 442 (95.7%) of the X-ray sources, with an expected false-match probability of ≈ 6.2%; we also selected four additional likely counterparts. The majority of the other 16 X-ray sources appear to be off-nuclear sources, sources associated with galaxy groups and clusters, high-redshift active galactic nuclei (AGNs), or spurious X-ray sources. A likelihood-ratio method is used for source matching, which effectively reduces the false-match probability at faint magnitudes compared to a simple error-circle matching method. We construct a master photometric catalog for the identified X-ray sources including up to 42 bands of UV-to-infrared data, and then calculate their photometric redshifts (photo-z's). High accuracy in the derived photo-z's is accomplished owing to (1) the up-to-date photometric data covering the full spectral energy distributions (SEDs) of the X-ray sources, (2) more accurate photometric data as a result of source deblending for ≈10% of the sources in the infrared bands and a few percent in the optical and near-infrared bands, (3) a set of 265 galaxy, AGN, and galaxy/AGN hybrid templates carefully constructed to best represent all possible SEDs, (4) the Zurich Extragalactic Bayesian Redshift Analyzer used to derive the photo-z's, which corrects the SED templates to best represent the SEDs of real sources at different redshifts and thus improves the photo-z quality. The reliability of the photo-z's is evaluated using the subsample of 220 sources with secure spectroscopic redshifts. We achieve an accuracy of |Δz|/(1 + z) ≈ 1% and an outlier [with |

  4. Stellar X-ray sources

    International Nuclear Information System (INIS)

    Katz, J.I.; Washington Univ., St. Louis, MO

    1988-01-01

    I Review some of the salient accomplishments of X-rap studies of compact objects. Progress in this field has closely followed the improvement of observational methods, particularly in angular resolution and duration of exposure. Luminous compact X-ray sources are accreting neutron stars or black holes. Accreting neutron stars may have characteristic temporal signatures, but the only way to establish that an X-ray source is a black hole is to measure its mass. A rough phenomenological theory is succesful, but the transport of angular momentum in accretion flows is not onderstood. A number of interesting complications have been observed, including precessing accretion discs, X-ray bursts, and the acceleration of jets in SS433. Many puzzles remain unsolved, including the excitation of disc precession, the nature of the enigmatic A- and gamma-ray source Cyg X-3, the mechanism by which slowly spinning accreting neutron stars lose angular momentum, and the superabundance of X-ray sources in globular clusters. 41 refs.; 5 figs

  5. The Chandra Source Catalog 2.0: Calibrations

    Science.gov (United States)

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

    2018-01-01

    Among the many enhancements implemented for the release of Chandra Source Catalog (CSC) 2.0 are improvements in the processing calibration database (CalDB). We have included a thorough overhaul of the CalDB software used in the processing. The software system upgrade, called "CalDB version 4," allows for a more rational and consistent specification of flight configurations and calibration boundary conditions. Numerous improvements in the specific calibrations applied have also been added. Chandra's radiometric and detector response calibrations vary considerably with time, detector operating temperature, and position on the detector. The CalDB has been enhanced to provide the best calibrations possible to each observation over the fifteen-year period included in CSC 2.0. Calibration updates include an improved ACIS contamination model, as well as updated time-varying gain (i.e., photon energy) and quantum efficiency maps for ACIS and HRC-I. Additionally, improved corrections for the ACIS quantum efficiency losses due to CCD charge transfer inefficiency (CTI) have been added for each of the ten ACIS detectors. These CTI corrections are now time and temperature-dependent, allowing ACIS to maintain a 0.3% energy calibration accuracy over the 0.5-7.0 keV range for any ACIS source in the catalog. Radiometric calibration (effective area) accuracy is estimated at ~4% over that range. We include a few examples where improvements in the Chandra CalDB allow for improved data reduction and modeling for the new CSC.This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  6. Star Formation In Nearby Clouds (SFiNCs): X-Ray and Infrared Source Catalogs and Membership

    Energy Technology Data Exchange (ETDEWEB)

    Getman, Konstantin V.; Broos, Patrick S.; Feigelson, Eric D.; Richert, Alexander J. W.; Ota, Yosuke [Department of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802 (United States); Kuhn, Michael A. [Instituto de Fisica y Astronomia, Universidad de Valparaiso, Gran Bretana 1111, Playa Ancha, Valparaiso (Chile); Millennium Institute of Astrophysics, MAS (Chile); Bate, Matthew R. [Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, Devon EX4 4SB (United Kingdom); Garmire, Gordon P. [Huntingdon Institute for X-Ray Astronomy, LLC, 10677 Franks Road, Huntingdon, PA 16652 (United States)

    2017-04-01

    The Star Formation in Nearby Clouds (SFiNCs) project is aimed at providing a detailed study of the young stellar populations and of star cluster formation in the nearby 22 star-forming regions (SFRs) for comparison with our earlier MYStIX survey of richer, more distant clusters. As a foundation for the SFiNCs science studies, here, homogeneous data analyses of the Chandra X-ray and Spitzer mid-infrared archival SFiNCs data are described, and the resulting catalogs of over 15,300 X-ray and over 1,630,000 mid-infrared point sources are presented. On the basis of their X-ray/infrared properties and spatial distributions, nearly 8500 point sources have been identified as probable young stellar members of the SFiNCs regions. Compared to the existing X-ray/mid-infrared publications, the SFiNCs member list increases the census of YSO members by 6%–200% for individual SFRs and by 40% for the merged sample of all 22 SFiNCs SFRs.

  7. Chandra and XMM-Newton observations of the low-luminosity X-ray pulsators SAX J1324.4−6200 and SAX J1452.8−5949

    NARCIS (Netherlands)

    Kaur, R.; Wijnands, R.; Patruno, A.; Testa, V.; Israel, G.; Degenaar, N.; Paul, B.; Kumar, B.

    2009-01-01

    We present results from our Chandra and XMM-Newton observations of two low-luminosity X-ray pulsators SAX J1324.4-6200 and SAX J1452.8-5949 which have spin periods of 172 and 437 s, respectively. The XMM-Newton spectra for both sources can be fitted well with a simple power-law model of photon

  8. Chandra X-ray Time-Domain Study of Alpha Centauri AB, Procyon, and their Environs

    Science.gov (United States)

    Ayres, Thomas R.

    2018-06-01

    For more than a decade, Chandra X-ray Observatory has been monitoring the central AB binary (G2V+K1V) of the α Centauri triple system with semi-annual pointings, using the High-Resolution Camera. This study has been extended in recent years to the mid-F subgiant, Procyon. The main objective is to follow the coronal (T~1MK) activity variations of the three stars, analogous to the Sun's 11-year sunspot cycle. Tentative periods of 20 yr and 8 yr have been deduced for α Cen A and B, respectively; but so far Procyon has shown only a slow, very modest decline in count rate, which could well reflect a slight instrumental degradation rather than intrinsic behavior. The negligible high-energy variability of Procyon sits in stark contrast to the dramatic factor of several to ten changes in the X-ray luminosities of α Cen AB and the Sun over their respective cycles. Further, although sunlike α Cen A has been observed by successive generations of X-ray observatories for nearly four decades, albeit sporadically, there are key gaps in the coverage that affect the determination of the cycle period. In fact, the most recent pointings suggest a downturn in A's count rate that might be signaling a shorter, more solar-like cycle following a delayed minimum in the 2005--2010 time frame (perhaps an exaggerated version of the extended solar minimum between recent Cycles 23 and 24). Beyond the coronal cycles of the three stars, the sequence of periodic X-ray images represents a unique time-domain history concerning steady as well as variable sources in the two 30'x30' fields. The most conspicuous of the variable objects -- in the α Cen field -- will be described here.

  9. Implications from XMM and Chandra Source Catalogs for Future Studies with Lynx

    Science.gov (United States)

    Ptak, Andrew

    2018-01-01

    Lynx will perform extremely sensitive X-ray surveys by combining very high-resolution imaging over a large field of view with a high effective area. These will include deep planned surveys and serendipitous source surveys. Here we discuss implications that can be gleaned from current Chandra and XMM-Newton serendipitous source surveys. These current surveys have discovered novel sources such as tidal disruption events, binary AGN, and ULX pulsars. In addition these surveys have detected large samples of normal galaxies, low-luminosity AGN and quasars due to the wide-area coverage of the Chandra and XMM-Newton source catalogs, allowing the evolution of these phenonema to be explored. The wide area Lynx surveys will probe down further in flux and will be coupled with very sensitive wide-area surveys such as LSST and SKA, allowing for detailed modeling of their SEDs and the discovery of rare, exotic sources and transient events.

  10. X-Ray Optics: Past, Present, and Future

    Science.gov (United States)

    Zhang, William W.

    2010-01-01

    X-ray astronomy started with a small collimated proportional counter atop a rocket in the early 1960s. It was immediately recognized that focusing X-ray optics would drastically improve both source location accuracy and source detection sensitivity. In the past 5 decades, X-ray astronomy has made significant strides in achieving better angular resolution, large photon collection area, and better spectral and timing resolutions, culminating in the three currently operating X-ray observatories: Chandra, XMM/Newton, and Suzaku. In this talk I will give a brief history of X-ray optics, concentrating on the characteristics of the optics of these three observatories. Then I will discuss current X-ray mirror technologies being developed in several institutions. I will end with a discussion of the optics for the International X-ray Observatory that I have been developing at Goddard Space Flight Center.

  11. X pinch a point x-ray source

    International Nuclear Information System (INIS)

    Garg, A.B.; Rout, R.K.; Shyam, A.; Srinivasan, M.

    1993-01-01

    X ray emission from an X pinch, a point x-ray source has been studied using a pin-hole camera by a 30 kV, 7.2 μ F capacitor bank. The wires of different material like W, Mo, Cu, S.S.(stainless steel) and Ti were used. Molybdenum pinch gives the most intense x-rays and stainless steel gives the minimum intensity x-rays for same bank energy (∼ 3.2 kJ). Point x-ray source of size (≤ 0.5 mm) was observed using pin hole camera. The size of the source is limited by the size of the pin hole camera. The peak current in the load is approximately 150 kA. The point x-ray source could be useful in many fields like micro lithography, medicine and to study the basic physics of high Z plasmas. (author). 4 refs., 3 figs

  12. Second Chandra Instrument Activated August 28

    Science.gov (United States)

    1999-08-01

    Cambridge, MA--NASA's Chandra X-ray Observatory opened a new era in astronomy Saturday, August 28, by making the most precise measurements ever recorded of the energy output from the 10 million degree corona of a star. Last weekend's observations came after the successful activation of an instrument developed by MIT that will allow a one-thousand-fold improvement in the capability to measure X-ray spectra from space. The new measurements, made with the High Energy Transmission Grating Spectrometer, join spectacular images taken last week by Chandra of the aftermath of a gigantic stellar explosion. The spectrometer is one of four key instruments aboard Chandra, and the second to be activated. The others will be turned on over the next two weeks. The spectrometer activated yesterday spreads the X-rays from Chandra's mirrors into a spectrum, much as a prism spreads light into its colors. The spectrum then can be read by Chandra's imaging detectors like a kind of cosmic bar code from which scientists can deduce the chemical composition and temperature of the corona. A corona is a region of hot gas and magnetic loops that extend hundreds of thousands of miles above the star's visible surface and is best studied with X-rays. "The success of the new spectrometer is definitely a major milestone for modern astronomy," said MIT Professor Claude R. Canizares, principal investigator for the instrument and associate director of the Chandra X-ray Observatory Center (CXC). "Within the first hour we had obtained the best X-ray spectrum ever recorded for a celestial source. We can already see unexpected features that will teach us new things about stars and about matter at high temperatures." The spectrometer measured X-rays from the star Capella, which is 40 light years away in the constellation Auriga. Capella is actually two stars orbiting one another and possibly interacting in ways that pump extra heat into the corona, which appears more active than that of the Sun. How a star

  13. NASA Names Premier X-Ray Observatory and Schedules Launch

    Science.gov (United States)

    1998-12-01

    Chicago until his death in 1995. The Chandra X-ray Observatory will help astronomers worldwide better understand the structure and evolution of the universe by studying powerful sources of X rays such as exploding stars, matter falling into black holes and other exotic celestial objects. X-radiation is an invisible form of light produced by multimillion degree gas. Chandra will provide X-ray images that are fifty times more detailed than previous missions. At more than 45 feet in length and weighing more than five tons, it will be one of the largest objects ever placed in Earth orbit by the Space Shuttle. Tyrel Johnson, a student at Priest River Lamanna High School in Priest River, Idaho, and Jatila van der Veen, a physics and astronomy teacher at Adolfo Camarillo High School in Camarillo, California, who submitted the winning name and essays, will receive a trip to the Kennedy Space Center in Florida to view the launch of the Chandra X-ray Observatory, a prize donated by TRW. Members of the contest's selection committee were Timothy Hannemann, executive vice president and general manager, TRW Space & Electronics Group; the late CNN correspondent John Holliman; former Secretary of the Air Force Sheila Widnall, professor of aeronautics at MIT; Charles Petit, senior writer for U.S. News & World Report; Sidney Wolff, Director, National Optical Astronomy Observatories; Martin Weisskopf, Advanced X-ray Astrophysics Facility project scientist, Marshall Space Flight Center, Huntsville, AL.; and Harvey Tananbaum, director of the Advanced X-ray Astrophysics Facility Science Center, Smithsonian Astrophysical Observatory, Cambridge, MA. The Chandra X-ray Observatory program is managed by the Marshall Center for the Office of Space Science, NASA Headquarters, Washington, DC. TRW Space and Electronics Group, Redondo Beach, CA, is NASA's prime contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations of the observatory for NASA

  14. Miniature x-ray source

    Science.gov (United States)

    Trebes, James E.; Bell, Perry M.; Robinson, Ronald B.

    2000-01-01

    A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

  15. Simultaneous Chandra and VLA Observations of the Transitional Millisecond Pulsar PSR J1023+0038: Anti-correlated X-Ray and Radio Variability

    Science.gov (United States)

    Bogdanov, Slavko; Deller, Adam T.; Miller-Jones, James C. A.; Archibald, Anne M.; Hessels, Jason W. T.; Jaodand, Amruta; Patruno, Alessandro; Bassa, Cees; D’Angelo, Caroline

    2018-03-01

    We present coordinated Chandra X-ray Observatory and Karl G. Jansky Very Large Array observations of the transitional millisecond pulsar PSR J1023+0038 in its low-luminosity accreting state. The unprecedented five hours of strictly simultaneous X-ray and radio continuum coverage for the first time unambiguously show a highly reproducible, anti-correlated variability pattern. The characteristic switches from the X-ray high mode into a low mode are always accompanied by a radio brightening with a duration that closely matches the X-ray low mode interval. This behavior cannot be explained by a canonical inflow/outflow accretion model where the radiated emission and the jet luminosity are powered by, and positively correlated with, the available accretion energy. We interpret this phenomenology as alternating episodes of low-level accretion onto the neutron star during the X-ray high mode that are interrupted by rapid ejections of plasma by the active rotation-powered pulsar, possibly initiated by a reconfiguration of the pulsar magnetosphere, that cause a transition to a less X-ray luminous mode. The observed anti-correlation between radio and X-ray luminosity has an additional consequence: transitional MSPs can make excursions into a region of the radio/X-ray luminosity plane previously thought to be occupied solely by black hole X-ray binary sources. This complicates the use of this luminosity relation for identifying candidate black holes, suggesting the need for additional discriminants when attempting to establish the true nature of the accretor.

  16. An X-ray and infrared survey of the Lynds 1228 cloud core

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Stephen L. [CASA, University of Colorado, Boulder, CO 80309-0389 (United States); Rebull, Luisa [Spitzer Science Center/Caltech, M/S 220-6, 1200 East California Blvd., Pasadena, CA 91125 (United States); Güdel, Manuel, E-mail: stephen.skinner@colorado.edu, E-mail: rebull@ipac.caltech.edu, E-mail: manuel.guedel@univie.ac.at [Department of Astrophysics, University of Vienna, Türkenschanzstr. 17, A-1180 Vienna (Austria)

    2014-04-01

    The nearby Lynds 1228 (L1228) dark cloud at a distance of ∼200 pc is known to harbor several young stars including the driving sources of the giant HH 199 and HH 200 Herbig-Haro (HH) outflows. L1228 has previously been studied at optical, infrared, and radio wavelengths but not in X-rays. We present results of a sensitive 37 ks Chandra ACIS-I X-ray observation of the L1228 core region. Chandra detected 60 X-ray sources, most of which are faint (<40 counts) and non-variable. Infrared counterparts were identified for 53 of the 60 X-ray sources using archival data from the Two Micron All-Sky Survey, the Spitzer Space Telescope, and the Wide-field Infrared Survey Explorer. Object classes were assigned using mid-IR colors for those objects with complete photometry, most of which were found to have colors consistent with extragalactic background sources. Seven young stellar object candidates were identified including the class I protostar HH 200-IRS which was detected as a faint hard X-ray source. No X-ray emission was detected from the luminous protostar HH 199-IRS. We summarize the X-ray and infrared properties of the detected sources and provide IR spectral energy distribution modeling of high-interest objects including the protostars driving the HH outflows.

  17. BeppoSAX and Chandra Observations of SAX J0103.2-7209 = 2E 0101.5-7225: A New Persistent 345 Second X-Ray Pulsar in the Small Magellanic Cloud.

    Science.gov (United States)

    Israel; Campana; Covino; Dal Fiume D; Gaetz; Mereghetti; Oosterbroek; Orlandini; Parmar; Ricci; Stella

    2000-03-10

    We report the results of a 1998 July BeppoSAX observation of a field in the Small Magellanic Cloud which led to the discovery of approximately 345 s pulsations in the X-ray flux of SAX J0103.2-7209. The BeppoSAX X-ray spectrum is well fitted by an absorbed power law with a photon index of approximately 1.0 plus a blackbody component with kT=0.11 keV. The unabsorbed luminosity in the 2-10 keV energy range is approximately 1.2x1036 ergs s-1. In a very recent Chandra observation, the 345 s pulsations are also detected. The available period measurements provide a constant period derivative of -1.7 s yr-1 over the last 3 years, making SAX J0103.2-7209 one of the most rapidly spinning up X-ray pulsars known. The BeppoSAX position (30&arcsec; uncertainty radius) is consistent with that of the Einstein source 2E 0101.5-7225 and the ROSAT source RX J0103.2-7209. This source was detected at a luminosity level of a few times 1035-1036 ergs s-1 in all data sets of past X-ray missions since 1979. The ROSAT HRI and Chandra positions are consistent with that of a mV=14.8 Be spectral-type star already proposed as the likely optical counterpart of 2E 0101.5-7225. We briefly report and discuss photometric and spectroscopic data carried out at the ESO telescopes 2 days before the BeppoSAX observation. We conclude that SAX J0103.2-7209 and 2E 0101.5-7225 are the same source: a relatively young and persistent X-ray pulsar in the SMC.

  18. Cross-correlating Cosmic IR and X-ray Background Fluctuations: Evidence of Significant Black Hole Populations Among the CIB Sources

    Science.gov (United States)

    Cappelluti, N.; Kashlinsky, A.; Arendt, R. G.; Comastri, A.; Fazio, G. G.; Finoguenov, A.; Hasinger, G.; Mather, J. C.; Miyaji, T; Moseley, S. H.

    2013-01-01

    In order to understand the nature of the sources producing the recently uncovered cosmic infrared background (CIB) fluctuations, we study cross-correlations between the fluctuations in the source-subtracted CIB from Spitzer/IRAC data and the unresolved cosmic X-ray background from deep Chandra observations. Our study uses data from the EGS/AEGIS field, where both data sets cover an approx = 8' x 45' region of the sky. Our measurement is the cross-power spectrum between the IR and X-ray data. The cross-power signal between the IRAC maps at 3.6 micron and 4.5 micron and the Chandra [0.5-2] keV data has been detected, at angular scales approx >20'', with an overall significance of approx = 3.8 sigma and approx. = 5.6 sigma, respectively. At the same time we find no evidence of significant cross-correlations at the harder Chandra bands. The cross-correlation signal is produced by individual IR sources with 3.6 micron and 4.5 micron magnitudes m(sub AB) approx. > 25-26 and [0.5-2] keV X-ray fluxes black holes than among the known populations. We discuss the various possible origins for the cross-power signal and show that neither local foregrounds nor the known remaining normal galaxies and active galactic nuclei can reproduce the measurements. These observational results are an important new constraint on theoretical modeling of the near-IR CIB fluctuations. local foregrounds, nor the known remaining normal galaxies and active galactic nuclei (AGN) can reproduce the measurements. These observational results are an important new constraint on theoretical modeling of the near-IR CIB fluctuations

  19. Studies in the X-Ray Emission of Clusters of Galaxies and Other Topics

    Science.gov (United States)

    Vrtilek, Jan; Thronson, Harley (Technical Monitor)

    2001-01-01

    The paper discusses the following: (1) X-ray study of groups of galaxies with Chandra and XMM. (2) X-ray properties of point sources in Chandra deep fields. (3) Study of cluster substructure using wavelet techniques. (4) Combined study of galaxy clusters with X-ray and the S-Z effect. Groups of galaxies are the fundamental building blocks of large scale structure in the Universe. X-ray study of the intragroup medium offers a powerful approach to addressing some of the major questions that still remain about almost all aspects of groups: their ages, origins, importance of composition of various galaxy types, relations to clusters, and origin and enrichment of the intragroup gas. Long exposures with Chandra have opened new opportunities for the study of X-ray background. The presence of substructure within clusters of galaxies has substantial implications for our understanding of cluster evolution as well as fundamental questions in cosmology.

  20. Implications of the Detection of X-rays From Pluto by Chandra for Its Solar Wind - Neutral Atmosphere Interaction

    Science.gov (United States)

    Lisse, C. M.

    2016-12-01

    Using the Chandra X-Ray Observatory, we have obtained low-resolution imaging X-ray spectrophotometry of the Pluto system in support of the New Horizons (NH) flyby. In a total of 174 ksec of on-target time, we measured 8 photons from 0.31 to 0.60 keV in a co-moving 11 x 11 pixel2 box (the 90% flux aperture for fixed background sources in the field) measuring 121,000 x 121,000 km2 (or 100 x 100 RPluto) at Pluto. The Pluto photons do not have the spectral shape of the background, are coincident with a 90% flux aperture co-moving with Pluto, and are not confused with any background source, so we consider them as sourced from the Pluto system. Allowing for background, we find a net signal of 6.8 counts and a statistical noise level of 1.2 counts, for a detection of Pluto at > 99.95%. The mean 0.31 - 0.60 keV X-ray power from Pluto is 200 +200/-100 MW, in the middle range of X-ray power levels seen for other known solar system emission sources: auroral precipitation, solar X-ray scattering, and charge exchange (CXE) between solar wind (SW) ions and atmospheric neutrals. We eliminate auroral effects as a source, as Pluto has no known magnetic field and the NH/Alice UV spectrometer detected no airglow from Pluto during the flyby. Atmospheric haze particles could produce resonant scattering of solar X-rays from Pluto, but the energy signature of the detected photons does not match the solar spectrum and estimates of Pluto's scattered X-ray emission are 2 to 3 orders of magnitude lower than seen in our observations. CXE-driven emission from hydrogenic and heliogenic SW carbon, nitrogen, and oxygen ions can produce the energy signature seen, and the 6 x 1025 neutral gas escape rate from Pluto deduced from NH data (Gladstone et al. 2016) can support the 3.0 +3.0/-1.5 x 1024 X-ray photons/s emission rate required by our observations. Using the SW proton density and speed measured by the NH/SWAP instrument in the vicinity of Pluto at the time of the photon emissions, we find a

  1. Transient soft X-ray sources

    International Nuclear Information System (INIS)

    Hayakawa, S.; Murakami, T.; Nagase, F.; Tanaka, Y.; Yamashita, K.

    1976-01-01

    A rocket observation of cosmic soft X-rays suggests the existence of transient, recurrent soft X-ray sources which are found variable during the flight time of the rocket. Some of the soft X-ray sources thus far reported are considered to be of this time. These sources are listed and their positions are shown. (Auth.)

  2. Chandra Sees Wealth Of Black Holes In Star-Forming Galaxies

    Science.gov (United States)

    2001-06-01

    NASA's Chandra X-ray Observatory has found new populations of suspected mid-mass black holes in several starburst galaxies, where stars form and explode at an unusually high rate. Although a few of these objects had been found previously, this is the first time they have been detected in such large numbers and could help explain their relationship to star formation and the production of even more massive black holes. At the 198th meeting of the American Astronomical Society in Pasadena, California, three independent teams of scientists reported finding dozens of X-ray sources in galaxies aglow with star formation. These X-ray objects appear point-like and are ten to a thousand times more luminous in X-rays than similar sources found in our Milky Way and the M81 galaxy. "Chandra gives us the ability to study the populations of individual bright X-ray sources in nearby galaxies in extraordinary detail," said Andreas Zezas, lead author from the Harvard-Smithsonian Center for Astrophysics team that observed The Antennae, a pair of colliding galaxies, and M82, a well-known starburst galaxy. "This allows us to build on earlier detections of these objects and better understand their relationship to starburst galaxies." Antennae-True Color Image True Color Image of Antennae Credit: NASA/SAO/G.Fabbiano et al. Press Image and Caption Kimberly Weaver, of NASA's Goddard Space Flight Center in Greenbelt, MD, lead scientist of the team that studied the starburst galaxy NGC 253, discussed the importance of the unusual concentration of these very luminous X-ray sources near the center of that galaxy. Four sources, which are tens to thousands of times more massive than the Sun, are located within 3,000 light years of the galaxy core. "This may imply that these black holes are gravitating toward the center of the galaxy where they could coalesce to form a single supermassive black hole," Weaver suggested. "It could be that this starburst galaxy is transforming itself into a quasar

  3. X-ray sources

    International Nuclear Information System (INIS)

    Masswig, I.

    1986-01-01

    The tkb market survey comparatively evaluates the X-ray sources and replacement tubes for stationary equipment currently available on the German market. It lists the equipment parameters of 235 commercially available X-ray sources and their replacement tubes and gives the criteria for purchase decisions. The survey has been completed with December 1985, and offers good information concerning medical and technical aspects as well as those of safety and maintenance. (orig.) [de

  4. The X-Ray Luminosity Functions of Field Low-Mass X-Ray Binaries in Early-Type Galaxies: Evidence for a Stellar Age Dependence

    Science.gov (United States)

    Lehmer, B. D.; Berkeley, M.; Zezas, A.; Alexander, D. M.; Basu-Zych, A.; Bauer, F. E.; Brandt, W. N.; Fragos, T.; Hornschemeier, A. E.; Kalogera, V.; hide

    2014-01-01

    We present direct constraints on how the formation of low-mass X-ray binary (LMXB) populations in galactic fields depends on stellar age. In this pilot study, we utilize Chandra and Hubble Space Telescope (HST) data to detect and characterize the X-ray point source populations of three nearby early-type galaxies: NGC 3115, 3379, and 3384. The luminosity-weighted stellar ages of our sample span approximately equal to 3-10 Gyr. X-ray binary population synthesis models predict that the field LMXBs associated with younger stellar populations should be more numerous and luminous per unit stellar mass than older populations due to the evolution of LMXB donor star masses. Crucially, the combination of deep Chandra and HST observations allows us to test directly this prediction by identifying and removing counterparts to X-ray point sources that are unrelated to the field LMXB populations, including LMXBs that are formed dynamically in globular clusters, Galactic stars, and background AGN/galaxies. We find that the "young" early-type galaxy NGC 3384 (approximately equals 2-5 Gyr) has an excess of luminous field LMXBs (L(sub x) approximately greater than (5-10) × 10(exp 37) erg s(exp -1)) per unit K-band luminosity (L(sub K); a proxy for stellar mass) than the "old" early-type galaxies NGC 3115 and 3379 (approximately equals 8-10 Gyr), which results in a factor of 2-3 excess of L(sub X)/L(sub K) for NGC 3384. This result is consistent with the X-ray binary population synthesis model predictions; however, our small galaxy sample size does not allow us to draw definitive conclusions on the evolution field LMXBs in general. We discuss how future surveys of larger galaxy samples that combine deep Chandra and HST data could provide a powerful new benchmark for calibrating X-ray binary population synthesis models.

  5. CHANDRA OBSERVATION OF THE TeV SOURCE HESS J1834-087

    International Nuclear Information System (INIS)

    Misanovic, Zdenka; Kargaltsev, Oleg; Pavlov, George G.

    2011-01-01

    Chandra ACIS observed the field of the extended TeV source HESS J1834-087 for 47 ks. A previous XMM-Newton EPIC observation of the same field revealed a point-like source (XMMU J183435.3-084443) and an offset region of faint extended emission. In the low-resolution, binned EPIC images the two appear to be connected. However, the high-resolution Chandra ACIS images do not support the alleged connection. In these images, XMMU J183435.3-084443 is resolved into a point source, CXOU J183434.9-084443 (L 0.5-8keV ≅ 2.3 x 10 33 erg s -1 , for a distance of 4 kpc; photon index Γ ≅ 1.1), and a compact (∼ 0.5-8keV ≅ 4.1 x 10 33 erg s -1 , Γ ≅ 2.7). The nature of the nebula is uncertain. We discuss a dust scattering halo and a pulsar-wind nebula as possible interpretations. Based on our analysis of the X-ray data, we re-evaluate the previously suggested interpretations of HESS J1834-087 and discuss a possible connection to the Fermi Large Area Telescope source 1FGL J1834.3-0842c. We also obtained an upper limit of 3 x 10 -14 erg cm -2 s -1 on the unabsorbed flux of the SGR J1833-0832 (in quiescence), which happened to be in the ACIS field of view.

  6. XAssist: A System for the Automation of X-ray Astrophysics Analysis

    Science.gov (United States)

    Ptak, A.

    2004-08-01

    XAssist is a NASA AISR-funded project for the automation of X-ray astrophysics. It is capable of data reprocessing, source detection, and preliminary spatial, temporal and spectral analysis for each source with sufficient counts. The bulk of the system is written in Python, which in turn drives underlying software (CIAO for Chandra data, etc.). Future work will include a GUI (mainly for beginners and status monitoring) and the exposure of at least some functionality as web services. The latter will help XAssist to eventually become part of the VO, making advanced queries possible, such as determining the X-ray fluxes of counterparts to HST or SDSS sources (including the use of unpublished X-ray data), and add the ability of ``on-the-fly'' X-ray processing. Pipelines are running on Chandra and XMM-Newton observations of galaxies to demonstrate XAssist's capabilities, and the results are available online (in real time) at http://www.xassist.org. XAssist itself as well as various associated projects are available for download.

  7. Deepest X-Rays Ever Reveal universe Teeming With Black Holes

    Science.gov (United States)

    2001-03-01

    For the first time, astronomers believe they have proof black holes of all sizes once ruled the universe. NASA's Chandra X-ray Observatory provided the deepest X-ray images ever recorded, and those pictures deliver a novel look at the past 12 billion years of black holes. Two independent teams of astronomers today presented images that contain the faintest X-ray sources ever detected, which include an abundance of active super massive black holes. "The Chandra data show us that giant black holes were much more active in the past than at present," said Riccardo Giacconi, of Johns Hopkins University and Associated Universities, Inc., Washington, DC. The exposure is known as "Chandra Deep Field South" since it is located in the Southern Hemisphere constellation of Fornax. "In this million-second image, we also detect relatively faint X-ray emission from galaxies, groups, and clusters of galaxies". The images, known as Chandra Deep Fields, were obtained during many long exposures over the course of more than a year. Data from the Chandra Deep Field South will be placed in a public archive for scientists beginning today. "For the first time, we are able to use X-rays to look back to a time when normal galaxies were several billion years younger," said Ann Hornschemeier, Pennsylvania State University, University Park. The group’s 500,000-second exposure included the Hubble Deep Field North, allowing scientists the opportunity to combine the power of Chandra and the Hubble Space Telescope, two of NASA's Great Observatories. The Penn State team recently acquired an additional 500,000 seconds of data, creating another one-million-second Chandra Deep Field, located in the constellation of Ursa Major. Chandra Deep Field North/Hubble Deep Field North Press Image and Caption The images are called Chandra Deep Fields because they are comparable to the famous Hubble Deep Field in being able to see further and fainter objects than any image of the universe taken at X-ray

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

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

  9. NuSTAR Observations of the Compton-Thick Active Galactic Nucleus and Ultraluminous X-Ray Source Candidate in NGC 5643

    DEFF Research Database (Denmark)

    Annuar, A.; Gandhi, P.; Alexander, D. M.

    2015-01-01

    We present two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the local Seyfert 2 active galactic nucleus (AGN) and an ultraluminous X-ray source (ULX) candidate in NGC 5643. Together with archival data from Chandra, XMM-Newton, and Swift-BAT, we perform a high-quality broadband s...

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

    Science.gov (United States)

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

    2013-01-01

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

  11. X-Ray Properties of AGN in Brightest Cluster Galaxies. I. A Systematic Study of the Chandra Archive in the 0.2 < z < 0.3 and 0.55 < z < 0.75 Redshift Range

    Science.gov (United States)

    Yang, Lilan; Tozzi, Paolo; Yu, Heng; Lusso, Elisabeta; Gaspari, Massimo; Gilli, Roberto; Nardini, Emanuele; Risaliti, Guido

    2018-05-01

    We present a search for nuclear X-ray emission in the brightest cluster galaxies (BCGs) of a sample of groups and clusters of galaxies extracted from the Chandra archive. The exquisite angular resolution of Chandra allows us to obtain robust photometry at the position of the BCG, and to firmly identify unresolved X-ray emission when present, thanks to an accurate characterization of the extended emission at the BCG position. We consider two redshift bins (0.2 soft (0.5–2 keV) or hard (2–7 keV) band is detected only in 14 and 9 BCGs (∼18% of the total samples), respectively. The X-ray photometry shows that at least half of the BCGs have a high hardness ratio, compatible with significant intrinsic absorption. This is confirmed by the spectral analysis with a power-law model plus intrinsic absorption. We compute the fraction of X-ray bright BCGs above a given hard X-ray luminosity, considering only sources with positive photometry in the hard band (12/5 sources in the low/high-z sample).

  12. Characterizing the X-ray Emission in Small Magellanic Cloud Supernova Remnants

    Science.gov (United States)

    Man, Nicole; Auchettl, Katie; Lopez, Laura

    2018-01-01

    The Small Magellanic Cloud is a close, metal-poor galaxy with active star formation, and it has a diverse population of 24 supernova remnants (SNRs) that have been identified at several wavelengths. Past work has characterized the X-ray emission in these sources separately and aimed to constrain their explosive origins from observations with Chandra and XMM-Newton. Three SNRs have possible evidence for Type Ia explosions based on strong Fe-L emission in their X-ray spectra, although the environments and intermediate-mass element abundances are more consistent with those of core-collapse SNe. In this poster, we analyze the archival Chandra and XMM-Newton observations of the SMC SNR sample, and we model the sources' X-ray spectra in a systematic way to derive the plasma properties and to constrain the nature of the explosions. In one SNR, we note the presence of an X-ray binary near the source's geometric center, suggesting the compact object was produced in the SN explosion. As one of only three SNRs known in the Local Group to host a binary system, this source is worthy of follow-up investigations to probe explosions of massive stars in binary systems.

  13. VizieR Online Data Catalog: Multiwavelength photometry of CDFS X-ray sources (Brusa+, 2009)

    Science.gov (United States)

    Brusa, M.; Fiore, F.; Santini, P.; Grazian, A.; Comastri, A.; Zamorani, G.; Hasinger, G.; Merloni, A.; Civano, F.; Fontana, A.; Mainieri, V.

    2010-03-01

    The co-evolution of host galaxies and the active black holes which reside in their centre is one of the most important topics in modern observational cosmology. Here we present a study of the properties of obscured active galactic nuclei (AGN) detected in the CDFS 1 Ms observation and their host galaxies. We limited the analysis to the MUSIC area, for which deep K-band observations obtained with ISAAC@VLT are available, ensuring accurate identifications of the counterparts of the X-ray sources as well as reliable determination of photometric redshifts and galaxy parameters, such as stellar masses and star formation rates. In particular, we: 1) refined the X-ray/infrared/optical association of 179 sources in the MUSIC area detected in the Chandra observation; 2) studied the host galaxies observed and rest frame colors and properties. (2 data files).

  14. X-Ray and optical study of low core density globular clusters NGC6144 and E3

    NARCIS (Netherlands)

    Lan, S.-H.; Kong, A.K.H.; Verbunt, F.W.M.; Lewin, W.H.G.; Bassa, C.G.; Anderson, S.F.; Pooley, D.

    2010-01-01

    We report on the Chandra X-ray Observatory and Hubble Space Telescope (HST) observations of two low coredensity globular clusters, NGC6144 and E3. By comparing the number of X-ray sources inside the half-mass radius to those outside, we found six X-ray sources within the half-mass radius of NGC6144,

  15. VARIABILITY OF OPTICAL COUNTERPARTS IN THE CHANDRA GALACTIC BULGE SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Britt, C. T.; Hynes, R. I.; Johnson, C. B.; Baldwin, A.; Collazzi, A.; Gossen, L. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Jonker, P. G.; Torres, M. A. P. [SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Nelemans, G. [Department of Astrophysics, IMAPP, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen (Netherlands); Maccarone, T. [Department of Physics, Texas Tech University, Box 41051, Science Building, Lubbock, TX 79409-1051 (United States); Steeghs, D.; Greiss, S. [Astronomy and Astrophysics, Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Heinke, C. [Department of Physics, University of Alberta, CCIS 4-183, Edmonton, AB T6G 2E1 (Canada); Bassa, C. G. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Villar, A. [Department of Physics, Massachussettes Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307 (United States); Gabb, M. [Department of Physics, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991 (United States)

    2014-09-01

    We present optical light curves of variable stars consistent with the positions of X-ray sources identified with the Chandra X-ray Observatory for the Chandra Galactic Bulge Survey (GBS). Using data from the Mosaic-II instrument on the Blanco 4 m Telescope at CTIO, we gathered time-resolved photometric data on timescales from ∼2 hr to 8 days over the 3/4 of the X-ray survey containing sources from the initial GBS catalog. Among the light curve morphologies we identify are flickering in interacting binaries, eclipsing sources, dwarf nova outbursts, ellipsoidal variations, long period variables, spotted stars, and flare stars. Eighty-seven percent of X-ray sources have at least one potential optical counterpart. Twenty-seven percent of these candidate counterparts are detectably variable; a much greater fraction than expected for randomly selected field stars, which suggests that most of these variables are real counterparts. We discuss individual sources of interest, provide variability information on candidate counterparts, and discuss the characteristics of the variable population.

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

    International Nuclear Information System (INIS)

    Marchesi, S.; Civano, F.; Urry, C. M.; Elvis, M.; Salvato, M.; Brusa, M.; Lanzuisi, G.; Vignali, C.; Comastri, A.; Gilli, R.; Zamorani, G.; Cappelluti, N.; Hasinger, G.; Miyaji, T.; Treister, E.; Allevato, V.; Finoguenov, A.; Cardamone, C.; Griffiths, R. E.; Karim, A.

    2016-01-01

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

  17. Chandra Images Provide New Vision of Cosmic Explosions

    Science.gov (United States)

    1999-09-01

    Images from NASA's Chandra X-ray Observatory released today reveal previously unobserved features in the remnants of three different supernova explosions. Two of the remnants G21.5-0.9 and PSR 0540-69 show dramatic details of the prodigious production of energetic particles by a rapidly rotating, highly magnetized neutron star, as well as the enormous shell structures produced by the explosions. The image of the third remnant, E0102-72, reveals puzzling spoke-like structures in its interior. G21.5-0.9, in the constellation of Scutum, is about 16,000 light years (1 light year = 6 trillion miles) from Earth. Chandra's image shows a bright nebula surrounded by a much larger diffuse cloud. Inside the inner nebula is a bright central source that is thought to be a rapidly rotating highly magnetized neutron star. A rotating neutron star acts like a powerful generator, creating intense electric voltages that accelerate electrons to speeds close to the speed of light. The total output of this generator is greater than a thousand suns. The fluffy appearance of the central nebula is thought to be due to magnetic field lines which constrain the motions of the high-energy electrons. "It's a remarkable image," said Dr. Patrick Slane of the Harvard-Smithsonian Center for Astrophysics. "Neither the inner core nor the outer shell has ever been seen before." "It is as though we have a set of Russian dolls, with structures embedded within structures," said Professor Gordon Garmire of Penn State University, and principal investigator of the Advanced CCD Imaging Spectrometer, the X-ray camera that was used to make two of the images. NASA's project scientist, Dr. Martin Weisskopf of the Marshall Space Flight Center said, "Chandra's capability to provide surprises and insights continues." PSR 0540-69 PSR 0540-69 The existence of a rotating neutron star, or pulsar, in the center of G21.5-0.9 is inferred from the appearance of the nebula and the energy distribution of X-rays and radio

  18. X-ray Outburst in Mira A

    OpenAIRE

    Karovska, M.; Schlegel, E.; Hack, W.; Wood, B.

    2005-01-01

    We report here the Chandra ACIS-S detection of a bright soft X-ray transient in the Mira AB interacting symbiotic-like binary. We resolved the system for the first time in the X-rays. Using Chandra and HST images we determined that the unprecedented outburst is likely associated with the cool AGB star (Mira A), the prototype of Mira-type variables. X-rays have never before been detected from an AGB star, and the recent activity signals that the system is undergoing dramatic changes. The total...

  19. OPTICAL PROPERTIES OF THE ULTRALUMINOUS X-RAY SOURCE HOLMBERG IX X-1 AND ITS STELLAR ENVIRONMENT

    International Nuclear Information System (INIS)

    Grise, F.; Kaaret, P.; Pakull, M. W.; Motch, C.

    2011-01-01

    Holmberg IX X-1 is an archetypal ultraluminous X-ray source (ULX). Here we study the properties of the optical counterpart and of its stellar environment using optical data from SUBARU/Faint Object Camera and Spectrograph, GEMINI/GMOS-N and Hubble Space Telescope (HST)/Advanced Camera for Surveys, as well as simultaneous Chandra X-ray data. The V ∼ 22.6 spectroscopically identified optical counterpart is part of a loose cluster with an age ∼ sun . The counterpart is more luminous than the other stars of the association, suggesting a non-negligible optical contribution from the accretion disk. An observed UV excess also points to non-stellar light similar to X-ray active low-mass X-ray binaries. A broad He II λ4686 emission line identified in the optical spectrum of the ULX further suggests optical light from X-ray reprocessing in the accretion disk. Using stellar evolutionary tracks, we have constrained the mass of the counterpart to be ∼> 10 M sun , even if the accretion disk contributes significantly to the optical luminosity. Comparison of the photometric properties of the counterpart with binary models show that the donor may be more massive, ∼> 25 M sun , with the ULX system likely undergoing case AB mass transfer. Finally, the counterpart exhibits photometric variability of 0.14 mag between two HST observations separated by 50 days which could be due to ellipsoidal variations and/or disk reprocessing of variable X-ray emission.

  20. Miniature x-ray point source for alignment and calibration of x-ray optics

    International Nuclear Information System (INIS)

    Price, R.H.; Boyle, M.J.; Glaros, S.S.

    1977-01-01

    A miniature x-ray point source of high brightness similar to that of Rovinsky, et al. is described. One version of the x-ray source is used to align the x-ray optics on the Argus and Shiva laser systems. A second version is used to determine the spatial and spectral transmission functions of the x-ray optics. The spatial and spectral characteristics of the x-ray emission from the x-ray point source are described. The physical constraints including size, intensity and thermal limitations, and useful lifetime are discussed. The alignment and calibration techniques for various x-ray optics and detector combinations are described

  1. The universe in X-rays

    CERN Document Server

    Hasinger, Günther

    2008-01-01

    In the last 45 years, X-ray astronomy has become an integral part of modern astrophysics and cosmology. There is a wide range of astrophysical objects and phenomena, where X-rays provide crucial diagnostics. In particular they are well suited to study hot plasmas and matter under extreme physical conditions in compact objects. This book summarizes the present status of X-ray astronomy in terms of observational results and their astrophysical interpretation. It is written for students, astrophysicists as well a growing community of physicists interested in the field. An introduction including historical material is followed by chapters on X-ray astronomical instrumentation. The next two parts summarize in 17 chapters the present knowledge on various classes of X-ray sources in the galactic and extragalactic realm. While the X-ray astronomical highlights discussed in this book are mainly based on results from ROSAT, ASCA, RXTE, BeppoSAX, Chandra and XMM-Newton, a final chapter provides an outlook on observation...

  2. THE NATURE OF THE BRIGHT ULX X-2 IN NGC 3921: A CHANDRA POSITION AND HST CANDIDATE COUNTERPART

    Energy Technology Data Exchange (ETDEWEB)

    Jonker, P. G.; Heida, M.; Torres, M. A. P.; Ratti, E. M. [SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Miller-Jones, J. C. A. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Fabian, A. C.; Walton, D. J. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Miniutti, G. [Centro de Astrobiologia (CSIC-INTA), Departamento de Astrofisica, ESA, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Roberts, T. P., E-mail: p.jonker@sron.nl [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)

    2012-10-10

    We report on Chandra observations of the bright ultraluminous X-ray (ULX) source in NGC 3921. Previous XMM-Newton observations reported in the literature show the presence of a bright ULX at a 0.5-10 keV luminosity of 2 Multiplication-Sign 10{sup 40} erg s{sup -1}. Our Chandra observation finds the source at a lower luminosity of Almost-Equal-To 8 Multiplication-Sign 10{sup 39} erg s{sup -1}; furthermore, we provide a Chandra position of the ULX accurate to 0.''7 at 90% confidence. The X-ray variability makes it unlikely that the high luminosity is caused by several separate X-ray sources. In three epochs of archival Hubble Space Telescope observations, we find a candidate counterpart to the ULX. There is direct evidence for variability between the two epochs of WFPC2 F814W observations with the observation obtained in 2000 showing a brighter source. Furthermore, converting the 1994 F336W and 2000 F300W WFPC2 and the 2010 F336W WFC3 observations to the Johnson U-band filter assuming a spectral type of O7I, we find evidence for a brightening of the U-band light in 2000. Using the higher resolution WFC3 observations, we resolve the candidate counterpart into two sources of similar color. We discuss the nature of the ULX and the probable association with the optical counterpart(s). Finally, we investigate a potential new explanation for some (bright) ULXs as the decaying stages of flares caused by the tidal disruption of a star by a recoiled supermassive black hole. However, we find that there should be at most only one of such systems within z = 0.08.

  3. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-20

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

  5. XMM-Newton 13H deep field - I. X-ray sources

    Science.gov (United States)

    Loaring, N. S.; Dwelly, T.; Page, M. J.; Mason, K.; McHardy, I.; Gunn, K.; Moss, D.; Seymour, N.; Newsam, A. M.; Takata, T.; Sekguchi, K.; Sasseen, T.; Cordova, F.

    2005-10-01

    We present the results of a deep X-ray survey conducted with XMM-Newton, centred on the UK ROSAT13H deep field area. This region covers 0.18 deg2, and is the first of the two areas covered with XMM-Newton as part of an extensive multiwavelength survey designed to study the nature and evolution of the faint X-ray source population. We have produced detailed Monte Carlo simulations to obtain a quantitative characterization of the source detection procedure and to assess the reliability of the resultant sourcelist. We use the simulations to establish a likelihood threshold, above which we expect less than seven (3 per cent) of our sources to be spurious. We present the final catalogue of 225 sources. Within the central 9 arcmin, 68 per cent of source positions are accurate to 2 arcsec, making optical follow-up relatively straightforward. We construct the N(>S) relation in four energy bands: 0.2-0.5, 0.5-2, 2-5 and 5-10 keV. In all but our highest energy band we find that the source counts can be represented by a double power law with a bright-end slope consistent with the Euclidean case and a break around 10-14yergcm-2s-1. Below this flux, the counts exhibit a flattening. Our source counts reach densities of 700, 1300, 900 and 300 deg-2 at fluxes of 4.1 × 10-16,4.5 × 10-16,1.1 × 10-15 and 5.3 × 10-15ergcm-2s-1 in the 0.2-0.5, 0.5-2, 2-5 and 5-10 keV energy bands, respectively. We have compared our source counts with those in the two Chandra deep fields and Lockman hole, and found our source counts to be amongst the highest of these fields in all energy bands. We resolve >51 per cent (>50 per cent) of the X-ray background emission in the 1-2 keV (2-5 keV) energy bands.

  6. Impacts of Chandra X-ray Observatory Public Communications and Engagement

    Science.gov (United States)

    Arcand, Kimberly K.; Watzke, Megan; Lestition, Kathleen; Edmonds, Peter

    2015-01-01

    The Chandra X-ray Observatory Center runs a multifaceted Public Communications & Engagement program encompassing press relations, public engagement, and education. Our goals include reaching a large and diverse audience of national and international scope, establishing direct connections and working relationships with the scientists whose research forms the basis for all products, creating peer-reviewed materials and activities that evolve from an integrated pipeline design and encourage users toward deeper engagement, and developing materials that target underserved audiences such as women, Spanish speakers, and the sight and hearing impaired. This talk will highlight some of the key features of our program, from the high quality curated digital presence to the cycle of research and evaluation that informs our practice at all points of the program creation. We will also discuss the main impacts of the program, from the tens of millions of participants reached through the establishment and sustainability of a network of science 'volunpeers.'

  7. Determining the nature of faint X-ray sources from the ASCA Galactic center survey

    Science.gov (United States)

    Lutovinov, A. A.; Revnivtsev, M. G.; Karasev, D. I.; Shimansky, V. V.; Burenin, R. A.; Bikmaev, I. F.; Vorob'ev, V. S.; Tsygankov, S. S.; Pavlinsky, M. N.

    2015-05-01

    We present the results of the the identification of six objects from the ASCA Galactic center and Galactic plane surveys: AX J173548-3207, AX J173628-3141, AX J1739.5-2910, AX J1740.4-2856, AX J1740.5-2937, and AX J1743.9-2846. Chandra, XMM-Newton, and XRT/Swift X-ray data have been used to improve the positions of the optical counterparts to these sources. Thereafter, we have carried out a series of spectroscopic observations of the established optical counterparts at the RTT-150 telescope. Analysis of X-ray and optical spectra as well as photometric measurements in a wide wavelength range based on optical and infrared catalogs has allowed the nature of the program sources to be determined. Two X-ray objects have been detected in the error circle of AX J173628-3141: one is a coronally active G star and the other may be a symbiotic star, a red giant with an accreting white dwarf. Three sources (AX J1739.5-2910, AX J1740.5-2937, AX J1743.9-2846) have turned out to be active G-K stars, presumably RS CVn objects, one (AX J1740.4-2856) is an M dwarf, and another one (AX J173548-3207) most likely a low-mass X-ray binary in its low state. The distances and corresponding luminosities of the sources in the soft X-ray band (0.5-10 keV) have been estimated; analysis of deep INTEGRAL Galactic center observations has not revealed a statistically significant flux at energies >20 keV from any of them.

  8. Jet Power and Black Hole Assortment Revealed in New Chandra Image

    Science.gov (United States)

    2008-01-01

    acceleration in this part of the jet is unknown. Hundreds of point-like sources are also seen in the Chandra image. Many of these are X-ray binaries that contain a stellar-mass black hole and a companion star in orbit around one another. Determining the population and properties of these black holes should help scientists better understand the evolution of massive stars and the formation of black holes. Another surprise was the detection of two particularly bright X-ray binaries. These sources may contain stellar mass black holes that are unusually massive, and this Chandra observation might have caught them gobbling up material at a high rate. In this image, low-energy X-rays are colored red, intermediate-energy X-rays are green, and the highest-energy X-rays detected by Chandra are blue. The dark green and blue bands running almost perpendicular to the jet are dust lanes that absorb X-rays. This dust lane was created when Centaurus A merged with another galaxy perhaps 100 million years ago. This research was presented at the American Astronomical Society meeting on January 9th by Gregory Sivakoff (The Ohio State University). Other team members include Ralph Kraft (Harvard-Smithsonian Center for Astrophysics), Martin Hardcastle (University of Hertfordshire), Diana Worrall (University of Bristol), and Andres Jordan (Smithsonian Astrophysical Observatory). NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

  9. The galactic X-ray sources

    International Nuclear Information System (INIS)

    Gursky, H.; Schreier, E.

    1975-01-01

    The current observational evidence on galactic X-ray sources is presented both from an astrophysical and astronomical point of view. The distributional properties of the sources, where they appear in the Galaxy, and certain average characteristics are discussed. In this way, certain properties of the X-ray sources can be deduced which are not apparent in the study of single objects. The properties of individual X-ray sources are then described. The hope is that more can be learnt about neutron stars and black holes, their physical properties, their origin and evolution, and their influence on other galactic phenomena. Thus attention is paid to those elements of data which appear to have the most bearing on these questions. (Auth.)

  10. Compact X-ray sources: X-rays from self-reflection

    Science.gov (United States)

    Mangles, Stuart P. D.

    2012-05-01

    Laser-based particle acceleration offers a way to reduce the size of hard-X-ray sources. Scientists have now developed a simple scheme that produces a bright flash of hard X-rays by using a single laser pulse both to generate and to scatter an electron beam.

  11. X-rays from stars

    Science.gov (United States)

    Güdel, Manuel

    2004-07-01

    Spectroscopic studies available from Chandra and XMM-Newton play a pivotal part in the understanding of the physical processes in stellar (magnetic and non-magnetic) atmospheres. It is now routinely possible to derive densities and to study the influence of ultraviolet radiation fields, both of which can be used to infer the geometry of the radiating sources. Line profiles provide important information on bulk mass motions and attenuation by neutral matter, e.g. in stellar winds. The increased sensitivity has revealed new types of X-ray sources in systems that were thought to be unlikely places for X-rays: flaring brown dwarfs, including rather old, non-accreting objects, and terminal shocks in jets of young stars are important examples. New clues concerning the role of stellar high-energy processes in the modification of the stellar environment (ionization, spallation, etc.) contribute significantly to our understanding of the "astro-ecology" in forming planetary systems. Technological limitations are evident. The spectral resolution has not reached the level where bulk mass motions in cool stars become easily measurable. Higher resolution would also be important to perform X-ray "Doppler imaging" in order to reconstruct the 3-D distribution of the X-ray sources around a rotating star. Higher sensitivity will be required to perform high-resolution spectroscopy of weak sources such as brown dwarfs or embedded pre-main-sequence sources. A new generation of satellites such as Constellation-X or XEUS should pursue these goals.

  12. Lunar Prospecting With Chandra

    Science.gov (United States)

    2003-09-01

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

  13. CHANDRA AND XMM-NEWTON X-RAY OBSERVATIONS OF THE HYPERACTIVE T TAURI STAR RY TAU

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Stephen L. [Center for Astrophysics and Space Astronomy (CASA), Univ. of Colorado, Boulder, CO 80309-0389 (United States); Audard, Marc [Dept. of Astronomy, University of Geneva, Ch. d’Ecogia 16, CH-1290 Versoix (Switzerland); Güdel, Manuel, E-mail: stephen.skinner@colorado.edu, E-mail: marc.audard@unige.ch, E-mail: manuel.guedel@univie.ac.at [Dept. of Astrophysics, Univ. of Vienna, Türkenschanzstr. 17, A-1180 Vienna (Austria)

    2016-07-20

    We present results of pointed X-ray observations of the accreting jet-driving T Tauri star RY Tau using Chandra and XMM-Newton . We obtained high-resolution grating spectra and excellent-quality CCD spectra and light curves with the objective of identifying the physical mechanisms underlying RY Tau’s bright X-ray emission. Grating spectra reveal numerous emission lines spanning a broad range of temperature superimposed on a hot continuum. The X-ray emission measure distribution is dominated by very hot plasma at T {sub hot} ∼ 50 MK, but higher temperatures were present during flares. A weaker cool plasma component is also present as revealed by low-temperature lines such as O viii. X-ray light curves show complex variability consisting of short-duration (∼hours) superhot flares accompanied by fluorescent Fe emission at 6.4 keV superimposed on a slowly varying (∼one day) component that may be tied to stellar rotation. The hot flaring component is undoubtedly of magnetic (e.g., coronal) origin. Soft- and hard-band light curves undergo similar slow variability implying that at least some of the cool plasma shares a common magnetic origin with the hot plasma. Any contribution to the X-ray emission from cool shocked plasma is small compared to the dominant hot component but production of individual low-temperature lines such as O viii in an accretion shock is not ruled out.

  14. REVISITING THE SHORT-TERM X-RAY SPECTRAL VARIABILITY OF NGC 4151 WITH CHANDRA

    International Nuclear Information System (INIS)

    Wang Junfeng; Fabbiano, G.; Elvis, M.; Zezas, A.; Karovska, M.; Risaliti, G.

    2010-01-01

    We present new X-ray spectral data for the Seyfert 1 nucleus in NGC 4151 observed with Chandra for ∼200 ks. A significant ACIS pileup is present, resulting in a nonlinear count rate variation during the observation. With pileup corrected spectral fitting, we are able to recover the spectral parameters and find consistency with those derived from unpiled events in the ACIS readout streak and outer region from the bright nucleus. The absorption corrected 2-10 keV flux of the nucleus varied between 6 x 10 -11 erg s -1 cm -2 and 10 -10 erg s -1 cm -2 (L 2-10 k eV ∼ 1.3-2.1 x 10 42 erg s -1 ). Similar to earlier Chandra studies of NGC 4151 at a historical low state, the photon indices derived from the same absorbed power-law model are Γ ∼ 0.7-0.9. However, we show that Γ is highly dependent on the adopted spectral models. Fitting the power-law continuum with a Compton reflection component gives Γ ∼ 1.1. By including passage of non-uniform X-ray obscuring clouds, we can reproduce the apparent flat spectral states with Γ ∼ 1.7, typical for Seyfert 1 active galactic nuclei. The same model also fits the hard spectra from previous ASCA 'long look' observation of NGC 4151 in the lowest flux state. The spectral variability during our observation can be interpreted as variations in intrinsic soft continuum flux relative to a Compton reflection component that is from distant cold material and constant on short timescale, or variations of partially covering absorber in the line of sight toward the nucleus. An ionized absorber model with ionization parameter log ξ ∼ 0.8-1.1 can also fit the low-resolution ACIS spectra. If the partial covering model is correct, adopting a black hole mass M BH ∼4.6x10 7 M sun we constrain the distance of the obscuring cloud from the central black hole to be r ∼< 9 lt-day, consistent with the size of the broad emission line region of NGC 4151 from optical reverberation mapping.

  15. AN X-RAY COOLING-CORE CLUSTER SURROUNDING A LOW-POWER COMPACT STEEP SPECTRUM RADIO SOURCE 1321+045

    International Nuclear Information System (INIS)

    Kunert-Bajraszewska, M.; Siemiginowska, A.; Labiano, A.

    2013-01-01

    We discovered an X-ray cluster in a Chandra observation of the compact steep spectrum (CSS) radio source 1321+045 (z = 0.263). CSS sources are thought to be young radio objects at the beginning of their evolution and can potentially test the cluster heating process. 1321+045 is a relatively low-luminosity source and its morphology consists of two radio lobes on the opposite sides of a radio core with no evidence for jets or hotspots. The optical emission line ratios are consistent with an interstellar medium dominated by active galactic nucleus photoionization with a small contribution from star formation, and no contributions from shocks. Based on these ratios, we classify 1321+045 as a low excitation galaxy (LEG) and suggest that its radioactivity is in a coasting phase. The X-ray emission associated with the radio source is detected with 36.1 ± 8.3 counts, but the origin of this emission is highly uncertain. The current X-ray image of the cluster does not show any signatures of a radio source impact on the cluster medium. Chandra detects the cluster emission at >3σ level out to ∼60'' (240 kpc). We obtain the best-fit beta model parameters of the surface brightness profile of β = 0.58 ± 0.2 and a core radius of 9.4 +1.1 -0.9 arcsec. The average temperature of the cluster is equal to kT = 4.4 +0.5 -0.3 keV, with a temperature and cooling profile indicative of a cooling core. We measure the cluster luminosity L (0.5-2 k eV) = 3 × 10 44 erg s –1 and mass 1.5 × 10 14 M ☉

  16. AN X-RAY COOLING-CORE CLUSTER SURROUNDING A LOW-POWER COMPACT STEEP SPECTRUM RADIO SOURCE 1321+045

    Energy Technology Data Exchange (ETDEWEB)

    Kunert-Bajraszewska, M. [Torun Centre for Astronomy, Faculty of Physics, Astronomy and Informatics, NCU, Grudziacka 5, 87-100 Torun (Poland); Siemiginowska, A. [Harvard Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States); Labiano, A., E-mail: magda@astro.uni.torun.pl [Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir km. 4, E-28850 Torrejon de Ardoz, Madrid (Spain)

    2013-07-20

    We discovered an X-ray cluster in a Chandra observation of the compact steep spectrum (CSS) radio source 1321+045 (z = 0.263). CSS sources are thought to be young radio objects at the beginning of their evolution and can potentially test the cluster heating process. 1321+045 is a relatively low-luminosity source and its morphology consists of two radio lobes on the opposite sides of a radio core with no evidence for jets or hotspots. The optical emission line ratios are consistent with an interstellar medium dominated by active galactic nucleus photoionization with a small contribution from star formation, and no contributions from shocks. Based on these ratios, we classify 1321+045 as a low excitation galaxy (LEG) and suggest that its radioactivity is in a coasting phase. The X-ray emission associated with the radio source is detected with 36.1 {+-} 8.3 counts, but the origin of this emission is highly uncertain. The current X-ray image of the cluster does not show any signatures of a radio source impact on the cluster medium. Chandra detects the cluster emission at >3{sigma} level out to {approx}60'' (240 kpc). We obtain the best-fit beta model parameters of the surface brightness profile of {beta} = 0.58 {+-} 0.2 and a core radius of 9.4{sup +1.1}{sub -0.9} arcsec. The average temperature of the cluster is equal to kT = 4.4{sup +0.5}{sub -0.3} keV, with a temperature and cooling profile indicative of a cooling core. We measure the cluster luminosity L{sub (0.5-2{sub keV)}} = 3 Multiplication-Sign 10{sup 44} erg s{sup -1} and mass 1.5 Multiplication-Sign 10{sup 14} M{sub Sun}.

  17. New Constraints on the Geometry and Kinematics of Matter Surrounding the Accretion Flow in X-Ray Binaries from Chandra High-energy Transmission Grating X-Ray Spectroscopy

    Science.gov (United States)

    Tzanavaris, P.; Yaqoob, T.

    2018-03-01

    The narrow, neutral Fe Kα fluorescence emission line in X-ray binaries (XRBs) is a powerful probe of the geometry, kinematics, and Fe abundance of matter around the accretion flow. In a recent study it has been claimed, using Chandra High-Energy Transmission Grating (HETG) spectra for a sample of XRBs, that the circumnuclear material is consistent with a solar-abundance, uniform, spherical distribution. It was also claimed that the Fe Kα line was unresolved in all cases by the HETG. However, these conclusions were based on ad hoc models that did not attempt to relate the global column density to the Fe Kα line emission. We revisit the sample and test a self-consistent model of a uniform, spherical X-ray reprocessor against HETG spectra from 56 observations of 14 Galactic XRBs. We find that the model is ruled out in 13/14 sources because a variable Fe abundance is required. In two sources a spherical distribution is viable, but with nonsolar Fe abundance. We also applied a solar-abundance Compton-thick reflection model, which can account for the spectra that are inconsistent with a spherical model, but spectra with a broader bandpass are required to better constrain model parameters. We also robustly measured the velocity width of the Fe Kα line and found FWHM values of up to ∼5000 km s‑1. Only in some spectra was the Fe Kα line unresolved by the HETG.

  18. New Constraints on the Geometry and Kinematics of Matter Surrounding the Accretion Flow in X-Ray Binaries from Chandra High-Energy Transmission Grating X-Ray Spectroscopy

    Science.gov (United States)

    Tzanavaris, P.; Yaqoob, T.

    2018-01-01

    The narrow, neutral Fe Ka fluorescence emission line in X-ray binaries (XRBs) is a powerful probe of the geometry, kinematics, and Fe abundance of matter around the accretion flow. In a recent study it has been claimed, using Chandra High-Energy Transmission Grating (HETG) spectra for a sample of XRBs, that the circumnuclear material is consistent with a solar-abundance, uniform, spherical distribution. It was also claimed that the Fe Ka line was unresolved in all cases by the HETG. However, these conclusions were based on ad hoc models that did not attempt to relate the global column density to the Fe Ka line emission. We revisit the sample and test a self-consistent model of a uniform, spherical X-ray reprocessor against HETG spectra from 56 observations of 14 Galactic XRBs. We find that the model is ruled out in 13/14 sources because a variable Fe abundance is required. In two sources a spherical distribution is viable, but with nonsolar Fe abundance. We also applied a solar-abundance Compton-thick reflection model, which can account for the spectra that are inconsistent with a spherical model, but spectra with a broader bandpass are required to better constrain model parameters. We also robustly measured the velocity width of the Fe Ka line and found FWHM values of up to approx. 5000 km/s. Only in some spectra was the Fe Ka line unresolved by the HETG.

  19. ON NEUTRAL ABSORPTION AND SPECTRAL EVOLUTION IN X-RAY BINARIES

    International Nuclear Information System (INIS)

    Miller, J. M.; Cackett, E. M.; Reis, R. C.

    2009-01-01

    Current X-ray observatories make it possible to follow the evolution of transient and variable X-ray binaries across a broad range in luminosity and source behavior. In such studies, it can be unclear whether evolution in the low-energy portion of the spectrum should be attributed to evolution in the source, or instead to evolution in neutral photoelectric absorption. Dispersive spectrometers make it possible to address this problem. We have analyzed a small but diverse set of X-ray binaries observed with the Chandra High Energy Transmission Grating Spectrometer across a range in luminosity and different spectral states. The column density in individual photoelectric absorption edges remains constant with luminosity, both within and across source spectral states. This finding suggests that absorption in the interstellar medium strongly dominates the neutral column density observed in spectra of X-ray binaries. Consequently, evolution in the low-energy spectrum of X-ray binaries should properly be attributed to evolution in the source spectrum. We discuss our results in the context of X-ray binary spectroscopy with current and future X-ray missions.

  20. Fermi Non-detections of Four X-Ray Jet Sources and Implications for the IC/CMB Mechanism

    Science.gov (United States)

    Breiding, Peter; Meyer, Eileen T.; Georganopoulos, Markos; Keenan, M. E.; DeNigris, N. S.; Hewitt, Jennifer

    2017-11-01

    Since its launch in 1999, the Chandra X-ray observatory has discovered several dozen X-ray jets associated with powerful quasars. In many cases, the X-ray spectrum is hard and appears to come from a second spectral component. The most popular explanation for the kpc-scale X-ray emission in these cases has been inverse-Compton (IC) scattering of Cosmic Microwave Background (CMB) photons by relativistic electrons in the jet (the IC/CMB model). Requiring the IC/CMB emission to reproduce the observed X-ray flux density inevitably predicts a high level of gamma-ray emission, which should be detectable with the Fermi Large Area Telescope (LAT). In previous work, we found that gamma-ray upper limits from the large-scale jets of 3C 273 and PKS 0637-752 violate the predictions of the IC/CMB model. Here, we present Fermi/LAT flux density upper limits for the X-ray jets of four additional sources: PKS 1136-135, PKS 1229-021, PKS 1354+195, and PKS 2209+080. We show that these limits violate the IC/CMB predictions at a very high significance level. We also present new Hubble Space Telescope observations of the quasar PKS 2209+080 showing a newly detected optical jet, and Atacama Large Millimeter/submillimeter Array band 3 and 6 observations of all four sources, which provide key constraints on the spectral shape that enable us to rule out the IC/CMB model.

  1. Three Bright X-ray Sources in NGC 1313

    Science.gov (United States)

    Colbert, E.; Petre, R.; Schlegel, E.

    1992-12-01

    Three bright X-ray sources were detected in a recent (April/May 1991) ROSAT PSPC observation of the nearby (D ~ 4.5 Mpc) face--on barred spiral galaxy NGC 1313. Two of the sources were at positions coincident with X-ray sources detected by Fabbiano & Trinchieri (ApJ 315, 1987) in a previous (Jan 1980) Einstein IPC observation. The position of the brightest Einstein source is near the center of NGC 1313, and the second Einstein source is ~ 7' south of the ``nuclear'' source, in the outskirts of the spiral arms. A third bright X-ray source was detected in the ROSAT observation ~ 7' southwest of the ``nuclear'' source. We present X-ray spectra and X-ray images for the three bright sources found in the ROSAT observation of NGC 1313, and compare with previous Einstein results. Spectral analysis of these sources require them to have very large soft X-ray luminosities ( ~ 10(40) erg s(-1) ) when compared with typical X-ray sources in our Galaxy. Feasible explanations for the X-ray emission are presented. The third X-ray source is positively identified with the recently discovered (Ryder et. al., ApJ 1992) peculiar type-II supernova 1978K.

  2. Deconvolving the Nucleus of Centaurus A Using Chandra PSF Library

    Science.gov (United States)

    Karovska, Margarita

    2000-01-01

    Centaurus A (NGC 5128) is a giant early-type galaxy containing the nearest (at 3.5 Mpc) radio-bright Active Galactic Nucleus (AGN). Cen A was observed with the High Resolution Camera (HRC) on the Chandra X-ray Observatory on several occasions since the launch in July 1999. The high-angular resolution (less than 0.5 arcsecond) Chandra/HRC images reveal X ray multi-scale structures in this object with unprecedented detail and clarity, including the bright nucleus believed to be associated with a supermassive black hole. We explored the spatial extent of the Cen A nucleus using deconvolution techniques on the full resolution Chandra images. Model point spread functions (PSFs) were derived from the standard Chandra raytrace PSF library as well as unresolved point sources observed with Chandra. The deconvolved images show that the Cen A nucleus is resolved and asymmetric. We discuss several possible causes of this extended emission and of the asymmetries.

  3. When Worlds Collide: Chandra Observes Titanic Merger

    Science.gov (United States)

    2002-04-01

    lobes will continue to expand into space or fall back into Arp 220 is unknown. The center of Arp 220 is of particular interest. Chandra observations allowed astronomers to pinpoint an X-ray source at the exact location of the nucleus of one of the pre-merger galaxies. Another fainter X-ray source nearby may coincide with the nucleus of the other galaxy remnant. The X-ray power output of these point-like sources is greater than expected for stellar black holes accreting from companion stars. The authors suggest that these sources could be due to supermassive black holes at the centers of the merging galaxies. These two remnant sources are relatively weak, and provide strong evidence to support the theory that the extraordinary luminosity of Arp 220 - about a hundred times that of our Milky Way galaxy - is due to the rapid rate of star formation and not to an active, supermassive black hole in the center. However, in a few hundred million years, this balance of power may change. The two massive black holes could merge to produce a central supermassive black hole. This new arrangement could cause much more gas to fall into the central black hole, creating a power source equal to or greater than that due to star formation. "The unusual concentration of X-ray sources in the very center of Arp 220 suggests that we could be observing the early stages of the creation of a supermassive black hole and the eventual rise to power of an active galactic nucleus," said Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, another member of the team studying Arp 220. Clements and McDowell were joined on this research by an international group of researchers from the United States, United Kingdom and Spain. Chandra observed Arp 220 on June 24, 2000, for approximately 56,000 seconds using the Advanced CCD Imaging Spectrometer (ACIS) instrument. ACIS was developed for NASA by Pennsylvania State University, University Park, PA, and the Massachusetts Institute

  4. Chandra Captures Flare From Brown Dwarf

    Science.gov (United States)

    2000-07-01

    The first flare ever seen from a brown dwarf, or failed star, was detected by NASA's Chandra X-ray Observatory. The bright X-ray flare has implications for understanding the explosive activity and origin of magnetic fields of extremely low mass stars. Chandra detected no X-rays at all from LP 944-20 for the first nine hours of a twelve hour observation, then the source flared dramatically before it faded away over the next two hours. "We were shocked," said Dr. Robert Rutledge of the California Institute of Technology in Pasadena, the lead author on the discovery paper to appear in the July 20 issue of Astrophysical Journal Letters. "We didn't expect to see flaring from such a lightweight object. This is really the 'mouse that roared.'" Chandra LP 944-20 X-ray Image Press Image and Caption The energy emitted in the brown dwarf flare was comparable to a small solar flare, and was a billion times greater than observed X-ray flares from Jupiter. The flaring energy is believed to come from a twisted magnetic field. "This is the strongest evidence yet that brown dwarfs and possibly young giant planets have magnetic fields, and that a large amount of energy can be released in a flare," said Dr. Eduardo Martin, also of Caltech and a member of the team. Professor Gibor Basri of the University of California, Berkeley, the principal investigator for this observation, speculated that the flare "could have its origin in the turbulent magnetized hot material beneath the surface of the brown dwarf. A sub-surface flare could heat the atmosphere, allowing currents to flow and give rise to the X-ray flare -- like a stroke of lightning." LP 944-20 is about 500 million years old and has a mass that is about 60 times that of Jupiter, or 6 percent that of the Sun. Its diameter is about one-tenth that of the Sun and it has a rotation period of less than five hours. Located in the constellation Fornax in the southern skies, LP 944-20 is one of the best studied brown dwarfs because it is

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  6. The Evolution of Normal Galaxy X-Ray Emission Through Cosmic History: Constraints from the 6 MS Chandra Deep Field-South

    Science.gov (United States)

    Lehmer, B. D.; Basu-Zych, A. R.; Mineo, S.; Brandt, W. N.; Eurfrasio, R. T.; Fragos, T.; Hornschemeier, A. E.; Lou, B.; Xue, Y. Q.; Bauer, F. E.; hide

    2016-01-01

    We present measurements of the evolution of normal-galaxy X-ray emission from z (is) approx. 0-7 using local galaxies and galaxy samples in the approx. 6 Ms Chandra Deep Field-South (CDF-S) survey. The majority of the CDF-S galaxies are observed at rest-frame energies above 2 keV, where the emission is expected to be dominated by X-ray binary (XRB) populations; however, hot gas is expected to provide small contributions to the observed-frame (is) less than 1 keV emission at z (is) less than 1. We show that a single scaling relation between X-ray luminosity (L(sub x)) and star-formation rate (SFR) literature, is insufficient for characterizing the average X-ray emission at all redshifts. We establish that scaling relations involving not only SFR, but also stellar mass and redshift, provide significantly improved characterizations of the average X-ray emission from normal galaxy populations at z (is) approx. 0-7. We further provide the first empirical constraints on the redshift evolution of X-ray emission from both low-mass XRB (LMXB) and high-mass XRB (HMXB) populations and their scalings with stellar mass and SFR, respectively. We find L2 -10 keV(LMXB)/stellar mass alpha (1+z)(sub 2-3) and L2 -10 keV(HMXB)/SFR alpha (1+z), and show that these relations are consistent with XRB population-synthesis model predictions, which attribute the increase in LMXB and HMXB scaling relations with redshift as being due to declining host galaxy stellar ages and metallicities, respectively. We discuss how emission from XRBs could provide an important source of heating to the intergalactic medium in the early universe, exceeding that of active galactic nuclei.

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

    Science.gov (United States)

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

    2018-02-01

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

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

    International Nuclear Information System (INIS)

    Lisse, C. M.; Christian, D. J.; Wolk, S. J.; Günther, H. M.; Chen, C. H.; Grady, C. A.

    2017-01-01

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

  9. Chandra's X-ray Vision

    Indian Academy of Sciences (India)

    1999-07-23

    Jul 23, 1999 ... CXO is 13.8 metres long and its solar arrays have a wingspan of. 19.5 metres as shown in ... the Universe (for example, coronae of stars, matter ejected from .... The telescope system and the scientific instruments were put through ..... solve the puzzle about the origin of cosmic X-ray background- one of the ...

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

    Science.gov (United States)

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

    2002-12-01

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

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

    International Nuclear Information System (INIS)

    Lewin, W.H.G.; Joss, P.C.; Massachusetts Inst. of Tech., Cambridge; Massachusetts Inst. of Tech., Cambridge

    1981-01-01

    In this article we shall discuss the observed X-ray, optical, infrared and radio properties of the galactic bulge sources, with an emphasis on those that produce type I X-ray bursts. There is persuasive evidence that these burst sources and many other galactic bulge sources are neutron stars in low-mass, close-binary stellar systems. (orig./WL)

  12. X-ray reflection in oxygen-rich accretion discs of ultracompact X-ray binaries

    DEFF Research Database (Denmark)

    Madej, O. K.; Garcia, Jeronimo; Jonker, P. G.

    2014-01-01

    We present spectroscopic X-ray data of two candidate ultracompact X-ray binaries (UCXBs): 4U 0614+091 and 4U 1543-624. We confirm the presence of a broad O viii Ly alpha reflection line (at a parts per thousand 18 angstrom) using XMM-Newton and Chandra observations obtained in 2012 and 2013. The ...

  13. Secondary-source energy-dispersive x-ray spectrometer

    International Nuclear Information System (INIS)

    Larsen, R.P.; Tisue, G.T.

    1975-01-01

    A secondary-source energy-dispersive x-ray spectrometer has been built and tested. In this instrument the primary source of x rays is a tungsten-target tube powered by a high-voltage (75 kV), a high-power (3.7 kW) generator from a wavelength spectrometer (G.E. XRD-6). The primary polychromatic x rays irradiate an elemental foil, the secondary source. Its characteristic essentially monochromatic x rays are used to irradiate the sample. Fluorescent x rays from the sample are detected and resolved by a lithium-drifted silicon detector, multichannel-analyzer system. The design of the instrument provides a convenient means for changing the secondary, and hence, the energy of the excitation radiation

  14. Chandra Independently Determines Hubble Constant

    Science.gov (United States)

    2006-08-01

    A critically important number that specifies the expansion rate of the Universe, the so-called Hubble constant, has been independently determined using NASA's Chandra X-ray Observatory. This new value matches recent measurements using other methods and extends their validity to greater distances, thus allowing astronomers to probe earlier epochs in the evolution of the Universe. "The reason this result is so significant is that we need the Hubble constant to tell us the size of the Universe, its age, and how much matter it contains," said Max Bonamente from the University of Alabama in Huntsville and NASA's Marshall Space Flight Center (MSFC) in Huntsville, Ala., lead author on the paper describing the results. "Astronomers absolutely need to trust this number because we use it for countless calculations." Illustration of Sunyaev-Zeldovich Effect Illustration of Sunyaev-Zeldovich Effect The Hubble constant is calculated by measuring the speed at which objects are moving away from us and dividing by their distance. Most of the previous attempts to determine the Hubble constant have involved using a multi-step, or distance ladder, approach in which the distance to nearby galaxies is used as the basis for determining greater distances. The most common approach has been to use a well-studied type of pulsating star known as a Cepheid variable, in conjunction with more distant supernovae to trace distances across the Universe. Scientists using this method and observations from the Hubble Space Telescope were able to measure the Hubble constant to within 10%. However, only independent checks would give them the confidence they desired, considering that much of our understanding of the Universe hangs in the balance. Chandra X-ray Image of MACS J1149.5+223 Chandra X-ray Image of MACS J1149.5+223 By combining X-ray data from Chandra with radio observations of galaxy clusters, the team determined the distances to 38 galaxy clusters ranging from 1.4 billion to 9.3 billion

  15. Bayesian Multiscale Analysis of X-Ray Jet Features in High Redshift Quasars

    Science.gov (United States)

    McKeough, Kathryn; Siemiginowska, A.; Kashyap, V.; Stein, N.

    2014-01-01

    X-ray emission of powerful quasar jets may be a result of the inverse Compton (IC) process in which the Cosmic Microwave Background (CMB) photons gain energy by interactions with the jet’s relativistic electrons. However, there is no definite evidence that IC/CMB process is responsible for the observed X-ray emission of large scale jets. A step toward understanding the X-ray emission process is to study the Radio and X-ray morphologies of the jet. We implement a sophisticated Bayesian image analysis program, Low-count Image Reconstruction and Analysis (LIRA) (Esch et al. 2004; Conners & van Dyk 2007), to analyze jet features in 11 Chandra images of high redshift quasars (z ~ 2 - 4.8). Out of the 36 regions where knots are visible in the radio jets, nine showed detectable X-ray emission. We measured the ratios of the X-ray and radio luminosities of the detected features and found that they are consistent with the CMB radiation relationship. We derived a range of the bulk lorentz factor (Γ) for detected jet features under the CMB jet emission model. There is no discernible trend of Γ with redshift within the sample. The efficiency of the X-ray emission between the detected jet feature and the corresponding quasar also shows no correlation with redshift. This work is supported in part by the National Science Foundation REU and the Department of Defense ASSURE programs under NSF Grant no.1262851 and by the Smithsonian Institution, and by NASA Contract NAS8-39073 to the Chandra X-ray Center (CXC). This research has made use of data obtained from the Chandra Data Archive and Chandra Source Catalog, and software provided by the CXC in the application packages CIAO, ChIPS, and Sherpa. We thank Teddy Cheung for providing the VLA radio images. Connors, A., & van Dyk, D. A. 2007, Statistical Challenges in Modern Astronomy IV, 371, 101 Esch, D. N., Connors, A., Karovska, M., & van Dyk, D. A. 2004, ApJ, 610, 1213

  16. Discovery of Periodic Dips in the Brightest Hard X-Ray Source of M31 with EXTraS

    Science.gov (United States)

    Marelli, Martino; Tiengo, Andrea; De Luca, Andrea; Salvetti, David; Saronni, Luca; Sidoli, Lara; Paizis, Adamantia; Salvaterra, Ruben; Belfiore, Andrea; Israel, Gianluca; Haberl, Frank; D’Agostino, Daniele

    2017-12-01

    We performed a search for eclipsing and dipping sources in the archive of the EXTraS project—a systematic characterization of the temporal behavior of XMM-Newton point sources. We discovered dips in the X-ray light curve of 3XMM J004232.1+411314, which has been recently associated with the hard X-ray source dominating the emission of M31. A systematic analysis of XMM-Newton observations revealed 13 dips in 40 observations (total exposure time of ∼0.8 Ms). Among them, four observations show two dips, separated by ∼4.01 hr. Dip depths and durations are variable. The dips occur only during low-luminosity states ({L}0.2{--12}< 1× {10}38 erg s‑1), while the source reaches {L}0.2{--12}∼ 2.8× {10}38 erg s‑1. We propose that this system is a new dipping low-mass X-ray binary in M31 seen at high inclination (60°–80°) the observed dipping periodicity is the orbital period of the system. A blue HST source within the Chandra error circle is the most likely optical counterpart of the accretion disk. The high luminosity of the system makes it the most luminous (not ULX) dipper known to date.

  17. X-ray Optics Development at MSFC

    Science.gov (United States)

    Sharma, Dharma P.

    2017-01-01

    Development of high resolution focusing telescopes has led to a tremendous leap in sensitivity, revolutionizing observational X-ray astronomy. High sensitivity and high spatial resolution X-ray observations have been possible due to use of grazing incidence optics (paraboloid/hyperboloid) coupled with high spatial resolution and high efficiency detectors/imagers. The best X-ray telescope flown so far is mounted onboard Chandra observatory launched on July 23,1999. The telescope has a spatial resolution of 0.5 arc seconds with compatible imaging instruments in the energy range of 0.1 to 10 keV. The Chandra observatory has been responsible for a large number of discoveries and has provided X-ray insights on a large number of celestial objects including stars, supernova remnants, pulsars, magnetars, black holes, active galactic nuclei, galaxies, clusters and our own solar system.

  18. X-Ray Outburst from Young Star in McNeil's Nebula

    Science.gov (United States)

    2004-07-01

    Observations with NASA's Chandra X-ray Observatory captured an X-ray outburst from a young star, revealing a probable scenario for the intermittent brightening of the recently discovered McNeil's Nebula. It appears the interaction between the young star's magnetic field and an orbiting disk of gas can cause dramatic, episodic increases in the light from the star and disk, illuminating the surrounding gas. "The story of McNeil's Nebula is a wonderful example of the importance of serendipity in science," said Joel Kastner of the Rochester Institute of Technology in Rochester, New York, lead author of a paper in the July 22 issue of Nature describing the X-ray results. "Visible-light images were made of this region several months before Jay McNeil made his discovery, so it could be determined approximately when and by how much the star flared up to produce McNeil's Nebula." The small nebula, which lies in the constellation Orion about 1300 light years from Earth, was discovered with a 3-inch telescope by McNeil, an amateur astronomer from Paducah, Kentucky, in January 2004. In November 2002, a team led by Ted Simon of the Institute for Astronomy in Hawaii had observed the star-rich region with Chandra in search of young, X-ray emitting stars, and had detected several objects. Optical and infrared astronomers had, as part of independent surveys, also observed the region about a year later, in 2003. After the announcement of McNeil's discovery, optical, infrared and X-ray astronomers rushed to observe the region again. They found that a young star buried in the nebula had flared up, and was illuminating the nebula. This star was coincident with one of the X-ray sources discovered earlier by Simon. Chandra observations obtained by Kastner's group just after the optical outburst showed that the source had brightened fifty-fold in X-rays when compared to Simon's earlier observation. The visible-light eruption provides evidence that the cause of the X-ray outburst is the

  19. Compton backscattered collmated X-ray source

    Science.gov (United States)

    Ruth, Ronald D.; Huang, Zhirong

    2000-01-01

    A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

  20. Compton backscattered collimated x-ray source

    Science.gov (United States)

    Ruth, R.D.; Huang, Z.

    1998-10-20

    A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-20

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

  2. Detection of X-ray flares from AX J1714.1-3912, the unidentified source near RX J1713.7-3946

    Science.gov (United States)

    Miceli, Marco; Bamba, Aya

    2018-04-01

    Context. Molecular clouds are predicted to emit nonthermal X-rays when they are close to particle-accelerating supernova remnants (SNRs), and the hard X-ray source AX J1714.1-3912, near the SNR RX J1713.7-3946, has long been considered a candidate for diffuse nonthermal emission associated with cosmic rays diffusing from the remnant to a closeby molecular cloud. Aim. We aim at ascertaining the nature of this source by analyzing two dedicated X-ray observations performed with Suzaku and Chandra. Methods: We extracted images from the data in various energy bands, spectra, and light curves and studied the long-term evolution of the X-ray emission on the basis of the 4.5 yr time separation between the two observations. Results: We found that there is no diffuse emission associated with AX J1714.1-3912, which is instead the point-like source CXOU J171343.9-391205. We discovered rapid time variability (timescale 103 s), together with a high intrinsic absorption and a hard nonthermal spectrum (power law with photon index Γ 1.4). We also found that the X-ray flux of the source drops down by 1-2 orders of magnitude on a timescale of a few years. Conclusions: Our results suggest a possible association between AX J1714.1-3912 and a previously unknown supergiant fast X-ray transient, although further follow-up observations are necessary to prove this association definitively.

  3. Disentangling the gamma-ray emission towards Cygnus X: Sh2-104

    Science.gov (United States)

    Gotthelf, Eric

    2015-09-01

    We have just discovered distinct X-ray emission coincident with VER J2018+363, a TeV source recently resolved from the giant gamma-ray complex MGRO J2019+37 in the Cygnus region. NuSTAR reveals a hard point source and a diffuse nebula adjacent to and possibly part of Sh2-104, a compact HII region containing several young massive stellar clusters. There is reasonable evidence that these X-rays probe the origin of the gamma-ray flux, however, unrelated extragalactic sources need to be excluded. We propose a short Chandra observation to localize the X-ray emission to identify a putative pulsar or stellar counterpart(s). This is an important step to fully understand the energetics of the MGRO J2019+37 complex and the production of gamma-rays in star formation regions, in general.

  4. Testing the Paradigm that Ultraluminous X-Ray Sources as a Class Represent Accreting Intermediate-Mass Black Holes

    Science.gov (United States)

    Berghea, C. T.; Weaver, K. A.; Colbert, E. J. M.; Roberts, T. P.

    2008-11-01

    To test the idea that ultraluminous X-ray sources (ULXs) in external galaxies represent a class of accreting intermediate-mass black holes (IMBHs), we have undertaken a program to identify ULXs and a lower luminosity X-ray comparison sample with the highest quality data in the Chandra archive. We establish as a general property of ULXs that the most X-ray-luminous objects possess the flattest X-ray spectra (in the Chandra bandpass). No prior sample studies have established the general hardening of ULX spectra with luminosity. This hardening occurs at the highest luminosities (absorbed luminosity >=5 × 1039 erg s-1) and is in line with recent models arguing that ULXs are actually stellar mass black holes. From spectral modeling, we show that the evidence originally taken to mean that ULXs are IMBHs—i.e., the "simple IMBH model"—is nowhere near as compelling when a large sample of ULXs is looked at properly. During the last couple of years, XMM-Newton spectroscopy of ULXs has to a large extent begun to negate the simple IMBH model based on fewer objects. We confirm and expand these results, which validates the XMM-Newton work in a broader sense with independent X-ray data. We find that (1) cool-disk components are present with roughly equal probability and total flux fraction for any given ULX, regardless of luminosity, and (2) cool-disk components extend below the standard ULX luminosity cutoff of 1039 erg s-1, down to our sample limit of 1038.3 erg s-1. The fact that cool-disk components are not correlated with luminosity damages the argument that cool disks indicate IMBHs in ULXs, for which strong statistical support was never found.

  5. X-ray Transients in M31

    Science.gov (United States)

    Kong, A. K. H.; Garcia, M. R.; Primini, F. A.; Murray, S. S.; McClintock, J. E.

    2002-06-01

    A bright X-ray transient was detected by Chandra on 2002 June 2 with a series of 5 HRC-I snapshots. The new source CXOU J004154.6+405648 (R.A.=00h41m54s.64, Dec.=+40d56m48s.0, +/- 1", J2000) is discovered at a luminosity (0.3-10 keV) of 1.5 x 1038 erg/s (assuming an absorbed power-law model with photon index = 2 and NH = 1021 cm-2 at a distance of 780 kpc).

  6. Some observational aspects of compact galactic X-ray sources

    International Nuclear Information System (INIS)

    Heise, J.

    1982-01-01

    This thesis contains the following observations of compact galactic X-ray sources: i) the X-ray experiments onboard the Astronomical Netherlands Satellite ANS, ii) a rocket-borne ultra soft X-ray experiment and iii) the Objective Grating Spectrometer onboard the EINSTEIN observatory. In Chapter I the various types of compact galactic X-ray sources are reviewed and put into the perspective of earlier and following observations. In Chapter II the author presents some of the observations of high luminosity X-ray sources, made with ANS, including the detection of soft X-rays from the compact X-ray binary Hercules X-1 and the ''return to the high state'' of the black hole candidate Cygnus X-1. Chapter III deals with transient X-ray phenomena. Results on low luminosity galactic X-ray sources are collected in Chapter IV. (Auth.)

  7. A CHANDRA PERSPECTIVE ON GALAXY-WIDE X-RAY BINARY EMISSION AND ITS CORRELATION WITH STAR FORMATION RATE AND STELLAR MASS: NEW RESULTS FROM LUMINOUS INFRARED GALAXIES

    International Nuclear Information System (INIS)

    Lehmer, B. D.; Jenkins, L. P.; Alexander, D. M.; Goulding, A. D.; Roberts, T. P.; Bauer, F. E.; Brandt, W. N.; Ptak, A.

    2010-01-01

    We present new Chandra observations that complete a sample of seventeen (17) luminous infrared galaxies (LIRGs) with D H ∼ 20 cm -2 . The LIRGs in our sample have total infrared (8-1000 μm) luminosities in the range of L IR ∼ (1-8) x 10 11 L sun . The high-resolution imaging and X-ray spectral information from our Chandra observations allow us to measure separately X-ray contributions from active galactic nuclei and normal galaxy processes (e.g., X-ray binaries and hot gas). We utilized total infrared plus UV luminosities to estimate star formation rates (SFRs) and K-band luminosities and optical colors to estimate stellar masses (M * ) for the sample. Under the assumption that the galaxy-wide 2-10 keV luminosity (L gal HX ) traces the combined emission from high-mass X-ray binaries (HMXBs) and low-mass X-ray binaries, and that the power output from these components is linearly correlated with SFR and M * , respectively, we constrain the relation L gal HX = αM * + βSFR. To achieve this, we construct a Chandra-based data set composed of our new LIRG sample combined with additional samples of less actively star-forming normal galaxies and more powerful LIRGs and ultraluminous infrared galaxies (ULIRGs) from the literature. Using these data, we measure best-fit values of α = (9.05 ± 0.37) x 10 28 erg s -1 M -1 sun and β = (1.62 ± 0.22) x 10 39 erg s -1 (M sun yr -1 ) -1 . This scaling provides a more physically meaningful estimate of L gal HX , with ∼0.1-0.2 dex less scatter, than a direct linear scaling with SFR. Our results suggest that HMXBs dominate the galaxy-wide X-ray emission for galaxies with SFR/M * ∼>5.9 x 10 -11 yr -1 , a factor of ∼2.9 times lower than previous estimates. We find that several of the most powerful LIRGs and ULIRGs, with SFR/M * ∼> 10 -9 yr -1 , appear to be X-ray underluminous with respect to our best-fit relation. We argue that these galaxies are likely to contain X-ray binaries residing in compact star-forming regions

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-01

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

  9. Chandra Discovers Light Echo from the Milky Way's Black Hole

    Science.gov (United States)

    2007-01-01

    K. Baganoff of the Massachusetts Institute of Technology in Cambridge. "The huge appetite is there, but it's not being satisfied." During the outburst, the area close to the black hole would have been about 100,000 times brighter than it is currently. If such an outburst had occurred more recently, it likely would have been detected by an X-ray instrument, or would have produced similar features in other nearby clouds. Chandra X-ray Image of Sagittarius A* Chandra X-ray Image of Sagittarius A* "Our data show it has been 50 years or so since the black hole had its last decent meal," said Muno. "This is nothing like the feasting that black holes in other galaxies sometimes enjoy, but it gives unique knowledge about the feeding habits of our closest supermassive black hole." The details of how Sagittarius A* feeds remain unclear. For example, one possibility is that the black hole grows by pulling in matter from the winds of nearby young stars. Also, if there is a disk of material swirling around Sagittarius A*, it might be unstable in such a way that material migrates toward the black hole's edge in clumps, emitting X-rays before disappearing from the universe forever. The theoretical work is still being developed. Studying this light echo is also important because it illuminates and probes the poorly understood molecular clouds near the center of the galaxy. In particular, it gives information about the dense cores of these clouds where new stars may be forming. Variability in the X-ray emission between three Chandra observations in 2002, 2004 and 2005 argues against an alternate source for the light echo, which is that it came from a neutron star or black hole pulling matter away from a binary companion. This explanation is not favored because the data show the outburst would have been unusually long and bright for such a binary. These results were presented at the American Astronomical Society meeting in Seattle, Wash., and will appear in an upcoming issue of The

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

    Science.gov (United States)

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

    2013-02-01

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

  11. X-Ray Snapshots Capture the First Cries of Baby Stars

    Science.gov (United States)

    2000-11-01

    CXC PR: 00-27 Stars, like babies, make quite a fuss in their first days after birth. Astronomers using the Chandra X-ray Observatory have discovered that protostars--stars in their youngest, "neonatal" stage--are marked by powerful X rays from plasma ten times hotter and 100 to 100,000 times brighter than the flares on our Sun. This is all long before their nuclear furnaces of hydrogen even ignite, the mark of stellar maturity. The X-ray flares have also provided the closest look yet at the youngest stars in the universe, never before detected because they are hidden within dust and molecular clouds that filter all other types of light. Yohko Tsuboi of the Pennsylvania State University (Penn State) presents these findings today in a press conference at the meeting of the High Energy Astrophysics Division of the American Astronomical Society in Honolulu, Hawaii. "We peered at newborn stars deeply embedded in their cradle and found that their crying is much more tumultuous than we expected," said Tsuboi. "With Chandra, we now have a new tool to examine protostars, which have been impossible to gain access to in any other wavelength." Protostars located in the rho-Ophiuchi molecular cloud Protostars located in the rho-Ophiuchi molecular cloud 1 square light years field X-ray image around rho Ophiuchi molecular cloud core. Red colorrepresents less absorbed X rays, while blue represents absorbed X rays. Lightcurves for each sources are also shown. Tsuboi and her collaborators looked at the two youngest types of protostars: Class-0 (zero) protostars, about 10,000 years old; and Class-I protostars, about 100,000 years old. In human terms, these protostars are like one-hour-old and 10-hour-old babies, respectively. The transition from one class to another is marked by changes in the protostar's infrared spectrum as the gas and dust envelope diminishes. The envelope has been well studied by infrared and radio astronomers. Protostars themselves and their most extreme

  12. On the nature of the ultraluminous X-ray transient in Cen~A (NGC 5128)

    OpenAIRE

    Ghosh, Kajal K.; Finger, Mark H.; Swartz, Douglas A.; Tennant, Allyn F.; Wu, Kinwah

    2005-01-01

    We combine 9 ROSAT, 9 Chandra, and 2 XMM-Newton observations of the Cen~A galaxy to obtain the X-ray light curve of 1RXH J132519.8-430312 (=CXOU J132519.9$-$430317) spanning 1990 to 2003. The source reached a peak 0.1-2.4 keV flux F_X>10^{-12} ergs cm^{-2} s^{-1} during a 10~day span in 1995 July. The inferred peak isotropic luminosity of the source therefore exceeded 3 10^{39} ergs s^{-1}, which places the source in the class of ultra-luminous X-ray sources. Coherent pulsations at 13.264 Hz ...

  13. Optical observations of binary X-ray sources

    International Nuclear Information System (INIS)

    Boynton, P.E.

    1975-01-01

    The contribution to the recent progress in astronomy made by optical observations is pointed out. The optical properties of X-ray sources help to establish the physical nature of these objects. The current observational evidence on the binary X-ray sources HZ Her/Her X-1 and HDE 226868/Cyg X-1 is reported. (P.J.S.)

  14. The Chandra Source Catalog 2.0: Combining Data for Processing (or How I learned 17 different words for "group")

    Science.gov (United States)

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

    2018-01-01

    The Second Chandra Source Catalog (CSC2.0) combines data at multiple stages to improve detection efficiency, enhance source region identification, and match observations of the same celestial source taken with significantly different point spread functions on Chandra's detectors. The need to group data for different reasons at different times in processing results in a hierarchy of groups to which individual sources belong. Source data are initially identified as belonging to each Chandra observation ID and number (an "obsid"). Data from each obsid whose pointings are within sixty arcseconds of each other are reprojected to the same aspect reference coordinates and grouped into stacks. Detection is performed on all data in the same stack, and individual sources are identified. Finer source position and region data are determined by further processing sources whose photons may be commingled together, grouping such sources into bundles. Individual stacks which overlap to any extent are grouped into ensembles, and all stacks in the same ensemble are later processed together to identify master sources and determine their properties.We discuss the basis for the various methods of combining data for processing and precisely define how the groups are determined. We also investigate some of the issues related to grouping data and discuss what options exist and how groups have evolved from prior releases.This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  15. The Ultracompact Nature of the Black Hole Candidate X-Ray Binary 47 Tuc X9

    Science.gov (United States)

    Bahramian, Arash; Heinke, Craig O.; Tudor, Vlad; Miller-Jones, James C. A.; Bogdanov, Slavko; Maccarone, Thomas J.; Knigge, Christian; Sivakoff, Gregory R.; Chomiuk, Laura; Strader, J.; hide

    2017-01-01

    47 Tuc X9 is a low-mass X-ray binary (LMXB) in the globular cluster 47 Tucanae, and was previously thought to be a cataclysmic variable. However, Miller-Jones et al. recently identified a radio counterpart to X9 (inferring a radio X-ray luminosity ratio consistent with black hole LMXBs), and suggested that the donor star might be a white dwarf. We report simultaneous observations of X9 performed by Chandra, NuSTAR and Australia Telescope Compact Array. We find a clear 28.18+/- 0.02-min periodic modulation in the Chandra data, which we identify as the orbital period, confirming this system as an ultracompact X-ray binary. Our X-ray spectral fitting provides evidence for photoionized gas having a high oxygen abundance in this system, which indicates a CO white dwarf donor. We also identify reflection features in the hard X-ray spectrum, making X9 the faintest LMXB to show X-ray reflection. We detect an approx. 6.8-d modulation in the X-ray brightness by a factor of 10, in archival Chandra, Swift and ROSAT data. The simultaneous radio X-ray flux ratio is consistent with either a black hole primary or a neutron star primary, if the neutron star is a transitional millisecond pulsar. Considering the measured orbital period (with other evidence of a white dwarf donor), and the lack of transitional millisecond pulsar features in the X-ray light curve, we suggest that this could be the first ultracompact black hole X-ray binary identified in our Galaxy.

  16. Observations of EUV and X-ray Emission from Comets

    Science.gov (United States)

    Lisse, C.

    The unexpected discovery of x-ray emission from Comet Hyakutake in March 1996 (Lisse et al. 1996) produced a number of questions about the physical mechanism producing the radiation. The original detection and subsequent observations have shown that the very soft (best fit thermal bremsstrahlung model kT0.2 keV) emission is due to an interaction between the solar wind and the comet's atmosphere. Using the results from the more than 15 comets detected to date in x-rays, I report here on the latest results on cometary x-ray emission, including new results from Chandra, and show that charge exchange between highly ionized minor ions in the solar wind and neutral gases in the cometary coma is the most likely operative mechanism. I then use this result to study a number of problems of astrophysical interest: the nature of the cometary coma, other possible sources of x-ray emission in the solar system, the structure of the solar wind in the heliosphere, and the source of the local x-ray background.

  17. RADIO-QUIET AND RADIO-LOUD PULSARS: SIMILAR IN GAMMA-RAYS BUT DIFFERENT IN X-RAYS

    Energy Technology Data Exchange (ETDEWEB)

    Marelli, M.; Mignani, R. P.; Luca, A. De; Salvetti, D. [INAF—Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, I-20133, Milano (Italy); Parkinson, P. M. Saz [Santa Cruz Institute for Particle Physics, Department of Physics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Hartog, P. R. Den [Stanford University HEPL/KIPAC, 452 Lomita Mall, Stanford, CA 94305-4085 (United States); Wolff, M. T., E-mail: marelli@iasf-milano.inaf.it [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States)

    2015-04-01

    We present new Chandra and XMM-Newton observations of a sample of eight radio-quiet (RQ) γ-ray pulsars detected by the Fermi Large Area Telescope. For all eight pulsars we identify the X-ray counterpart, based on the X-ray source localization and the best position obtained from γ-ray pulsar timing. For PSR J2030+4415 we found evidence for a ∼10″-long pulsar wind nebula. Our new results consolidate the work from Marelli et al. and confirm that, on average, the γ-ray-to-X-ray flux ratios (F{sub γ}/F{sub X}) of RQ pulsars are higher than for the radio-loud (RL) ones. Furthermore, while the F{sub γ}/F{sub X} distribution features a single peak for the RQ pulsars, the distribution is more dispersed for the RL ones, possibly showing two peaks. We discuss possible implications of these different distributions based on current models for pulsar X-ray emission.

  18. Study of characteristic X-ray source and its applications

    International Nuclear Information System (INIS)

    Li Fuquan

    1994-11-01

    The law of characteristic X-rays emitted by target element under the radiation of isotope source in a range of low energy is discussed. Both the way of improving the rate of γ-X conversion and the method to eliminate the influence of scatter rays are introduced. The influence of the variation of isotopes source, targets and the relative position of source-target to the output of X-rays is also discussed and then the conditions of improving signal-to-noise radio is presented. The X-ray source based on these results can produce different energy X-rays, and so can be broadly used on nuclear instruments and other fields as a low energy source. The thickness gauge, as one of the applications, has succeeded in thickness measuring of the different materials in large range, and it presents a new application field for characteristic X-ray source. (11 figs., 10 tabs.)

  19. Intraday X-Ray Variability of QSOs/AGN Using the Chandra Archives

    Science.gov (United States)

    Tartamella, C.; Busche, J.

    2005-05-01

    X-ray variability is a common characteristic of Active Galactic Nuclei (AGN), and it can be used to probe the nuclear region at short time scales. Quantitative analysis of this variability has been difficult due to low signal-to-noise ratios and short time baselines, but serendipitous Chandra data acquired within the last six years have opened the door to such analysis. Cross-correlation of the Chandra archives with QSO/AGN catalogs on NASA's HEASARC website (e.g. Veron, Sloan) yields a sample of 50+ objects that satisfy the following criteria: absolute magnitude M≤ -22.5, proper time baselines greater than 2 hours, and count rates leading to 10% error bars for 8+ flux points on the light curve. The sample includes a range of red-shifts, magnitudes, and type (e.g. radio loud, radio quiet), and hence may yield empirical clues about luminosity or evolutionary trends. As a beginning of such analysis, we present 11 light curves for 9 objects for which the exposure time was greater than 10 hours. The variability was analyzed using three different statistical methods. The Kolmogorov-Smirnov (KS) test proved to be impractical because of the unavoidably small number of data points and the simplistic nature of the test. A χ2 test indicated in most cases that there were significant departures from constant brightness (as expected). Autocorrelation plots were also generated for each light curve. With more work and a larger sample size, these plots can be used to identify any trends in the lightcurve such as whether the variability is stochastic or periodic in nature. This test was useful even with the small number of datapoints available. In future work, more sophisticated analyses based on Fourier series, power density spectra, or wavelets are likely to yield more meaningful and useful results.

  20. High-intensity laser synchrotron x-ray source

    International Nuclear Information System (INIS)

    Pogorelsky, I.V.

    1995-10-01

    A laser interacting with a relativistic electron beam behaves like a virtual wiggler of an extremely short period equal to half of the laser wavelength. This approach opens a route to relatively compact, high-brightness x-ray sources alternative or complementary to conventional synchrotron light sources. Although not new, the Laser Synchrotron Light Source (LSLS) concept is still waiting for a convincing demonstration. Available at the BNL's Accelerator Test Facility (ATF), a high-brightness electron beam and the high-power C0 2 laser may be used as prototype LSLS brick stones. In a feasible demonstration experiment, 10-GW, 100-ps C0 2 laser beam will be brought to a head-on collision with a 10-ps, 0.5-nC, 70 MeV electron bunch. Flashes of well-collimated, up to 9.36-keV (∼ Angstrom) x-rays of 10-ps pulse duration, with a flux of ∼10 19 photons/sec will be produced via linear Compton backscattering. The x-ray spectrum is tunable proportionally to a variable e-beam energy. A natural short-term extension of the proposed experiment would be further enhancement of the x-ray flux to a 10 21 -10 22 photons/sec level, after the ongoing ATF CO 2 laser upgrade to 1 TW peak power and electron bunch shortening to 3 ps. The ATF LSLS x-ray beamline, exceeding by orders of magnitude the peak fluxes attained at the National Synchrotron Light Source (NSLS) x-ray storage ring, may become attractive for certain users, e.g., for biological x-ray microscopy. In addition, a terawatt CO 2 laser will enable harmonic multiplication of the x-ray spectrum via nonlinear Compton scattering

  1. Revisiting the Short-term X-ray Spectral Variability of NGC 4151 with Chandra

    Science.gov (United States)

    Wang, Junfeng; Risaliti, G.; Fabbiano, G.; Elvis, M.; Zezas, A.; Karovska, M.

    2010-05-01

    We present new X-ray spectral data for the Seyfert 1 nucleus in NGC 4151 observed with Chandra for ~200 ks. A significant ACIS pileup is present, resulting in a nonlinear count rate variation during the observation. With pileup corrected spectral fitting, we are able to recover the spectral parameters and find consistency with those derived from unpiled events in the ACIS readout streak and outer region from the bright nucleus. The absorption corrected 2-10 keV flux of the nucleus varied between 6 × 10-11 erg s-1 cm-2 and 10-10 erg s-1 cm-2 (L 2-10 keV ~ 1.3-2.1 × 1042 erg s-1). Similar to earlier Chandra studies of NGC 4151 at a historical low state, the photon indices derived from the same absorbed power-law model are Γ ~ 0.7-0.9. However, we show that Γ is highly dependent on the adopted spectral models. Fitting the power-law continuum with a Compton reflection component gives Γ ~ 1.1. By including passage of non-uniform X-ray obscuring clouds, we can reproduce the apparent flat spectral states with Γ ~ 1.7, typical for Seyfert 1 active galactic nuclei. The same model also fits the hard spectra from previous ASCA "long look" observation of NGC 4151 in the lowest flux state. The spectral variability during our observation can be interpreted as variations in intrinsic soft continuum flux relative to a Compton reflection component that is from distant cold material and constant on short timescale, or variations of partially covering absorber in the line of sight toward the nucleus. An ionized absorber model with ionization parameter log ξ ~ 0.8-1.1 can also fit the low-resolution ACIS spectra. If the partial covering model is correct, adopting a black hole mass M_{BH}˜ 4.6× 10^7 M sun we constrain the distance of the obscuring cloud from the central black hole to be r <~ 9 lt-day, consistent with the size of the broad emission line region of NGC 4151 from optical reverberation mapping.

  2. Magnetic field strength of a neutron-star-powered ultraluminous X-ray source

    Science.gov (United States)

    Brightman, M.; Harrison, F. A.; Fürst, F.; Middleton, M. J.; Walton, D. J.; Stern, D.; Fabian, A. C.; Heida, M.; Barret, D.; Bachetti, M.

    2018-04-01

    Ultraluminous X-ray sources (ULXs) are bright X-ray sources in nearby galaxies not associated with the central supermassive black hole. Their luminosities imply they are powered by either an extreme accretion rate onto a compact stellar remnant, or an intermediate mass ( 100-105M⊙) black hole1. Recently detected coherent pulsations coming from three bright ULXs2-5 demonstrate that some of these sources are powered by accretion onto a neutron star, implying accretion rates significantly in excess of the Eddington limit, a high degree of geometric beaming, or both. The physical challenges associated with the high implied accretion rates can be mitigated if the neutron star surface field is very high (1014 G)6, since this suppresses the electron scattering cross-section, reducing the radiation pressure that chokes off accretion for high luminosities. Surface magnetic field strengths can be determined through cyclotron resonance scattering features7,8 produced by the transition of charged particles between quantized Landau levels. Here, we present the detection at a significance of 3.8σ of an absorption line at 4.5 keV in the Chandra spectrum of a ULX in M51. This feature is likely to be a cyclotron resonance scattering feature produced by the strong magnetic field of a neutron star. Assuming scattering off electrons, the magnetic field strength is implied to be 1011 G, while protons would imply a magnetic field of B 1015 G.

  3. Discovery of a highly variable dipping ultraluminous X-ray source in M94

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Dacheng; Irwin, Jimmy A. [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States); Webb, Natalie A.; Barret, Didier [CNRS, IRAP, 9 avenue du Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); Remillard, Ronald A., E-mail: dlin@ua.edu [MIT Kavli Institute for Astrophysics and Space Research, MIT, 70 Vassar Street, Cambridge, MA 02139-4307 (United States)

    2013-12-20

    We report the discovery of a new ultraluminous X-ray source (ULX) 2XMM J125048.6+410743 within the spiral galaxy M94. The source has been observed by ROSAT, Chandra, and XMM-Newton on several occasions, exhibiting as a highly variable persistent source or a recurrent transient with a flux variation factor of ≳100, a high duty cycle (at least ∼70%), and a peak luminosity of L {sub X} ∼ 2 × 10{sup 39} erg s{sup –1} (0.2-10 keV, absorbed). In the brightest observation, the source is similar to typical low-luminosity ULXs, with the spectrum showing a high-energy cutoff but harder than that from a standard accretion disk. There are also sporadical short dips, accompanied by spectral softening. In a fainter observation with L {sub X} ∼ 3.6 × 10{sup 38} erg s{sup –1}, the source appears softer and is probably in the thermal state seen in Galactic black hole X-ray binaries (BHBs). In an even fainter observation (L {sub X} ∼ 9 × 10{sup 37} erg s{sup –1}), the spectrum is harder again, and the source might be in the steep-power-law state or the hard state of BHBs. In this observation, the light curve might exhibit ∼7 hr (quasi-)periodic large modulations over two cycles. The source also has a possible point-like optical counterpart from Hubble Space Telescope images. In terms of the colors and the luminosity, the counterpart is probably a G8 supergiant or a compact red globular cluster containing ∼2 × 10{sup 5} K dwarfs, with some possible weak UV excess that might be ascribed to accretion activity. Thus, our source is a candidate stellar-mass BHB with a supergiant companion or with a dwarf companion residing in a globular cluster. Our study supports that some low-luminosity ULXs are supercritically accreting stellar-mass BHBs.

  4. Diagnostic X-ray sources-present and future

    Science.gov (United States)

    Behling, Rolf; Grüner, Florian

    2018-01-01

    This paper compares very different physical principles of X-ray production to spur ideation. Since more than 120 years, bremsstrahlung from X-ray tubes has been the workhorse of medical diagnostics. Generated by X-ray segments comprised of X-ray tubes and high-voltage generators in the various medical systems, X-ray photons in the spectral range between about 16 keV and 150 keV deliver information about anatomy and function of human patients and in pre-clinical animal studies. Despite of strides to employ the wave nature of X-rays as phase sensitive means, commercial diagnostic X-ray systems available until the time of writing still rely exclusively on measuring the attenuation and scattering of X-rays by matter. Significant activities in research aim at building highly brilliant short pulse X-ray sources, based on e.g. synchrotron radiation, free electron lasers and/or laser wake-field acceleration of electrons followed by wiggling with magnetic structures or Thomson scattering in bunches of light. While both approaches, non-brilliant and brilliant sources, have different scope of application, we speculate that a combination may expand the efficacy in medical application. At this point, however, severe technical and commercial difficulties hinder closing this gap. This article may inspire further development and spark innovation in this important field.

  5. Atomic Physics Measurements in Support of X-ray Astronomy

    Science.gov (United States)

    Beiersdorfer, Peter; Brown, G. V.; Kelley, R. E.; Kilbourne, C. A.; Leutenegger, M.; Porter, F. S.; Obst, M.; Lepson, J. K.; Desai, P.; Gu, M. F.

    2010-10-01

    X-ray astronomy has been a voracious consumer of atomic data, especially after the launch of the Chandra and XMM-Newton X-ray Observatories, which have produced very high-resolution grating spectra of point sources. One of the important issues has been to understand the physics underlying the Fe L-shell spectra, and the Fe XVII spectrum in particular. A lot of progress has been made, including measurements of the electron-impact and resonance excitation cross sections, which now provides a rather clear picture of the production mechanism of the Fe XVII spectrum. Recent measurements of the radiative rates provide additional information on the deexcitation channels, while investigations of dielectronic satellite transitions provide a measure of the electron temperature. Many questions, however, still remain. Work at LLNL was performed under the auspices of DOE under contract DE-AC53-07NA27344 and supported by NASA's APRA program under contracts NNH07AF81I and NNG06WF08I. Part of this work was supported by Chandra Cycle 10 Award AR9-0002X.

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

    International Nuclear Information System (INIS)

    Povic, M.; Perez GarcIa, A. M.; Bongiovanni, A.; Castaneda, H.; Lorenzo, M. Fernandez; Lara-Lopez, M. A.; Sanchez-Portal, M.; Cepa, J.; Alfaro, E.; Gallego, J.; Gonzalez-Serrano, J. I.; Gonzalez, J. J.

    2009-01-01

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

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    for the first time. As a follow up to our initial study of its nuclear region, we present the first results concerning the full galaxy from simultaneous NuSTAR, Chandra, and Very Long Baseline Array monitoring of the local starburst galaxy NGC 253. Above ~10 keV, nearly all the emission is concentrated within...... is detected at E > 40 keV. We report upper limits on diffuse inverse Compton emission for a range of spatial models. For the most extended morphologies considered, these hard X-ray constraints disfavor a dominant inverse Compton component to explain the γ-ray emission detected with Fermi and H.E.S.S. If NGC...

  8. Chandra Observation of Polaris: Census of Low-mass Companions

    Science.gov (United States)

    Evans, Nancy Remage; Guinan, Edward; Engle, Scott; Wolk, Scott J.; Schlegel, Eric; Mason, Brian D.; Karovska, Margarita; Spitzbart, Bradley

    2010-05-01

    We have observed Cepheid Polaris (α UMi A: F7 Ib [Aa] + F6 V [Ab]) with Chandra ACIS-I for 10 ks. An X-ray source was found at the location of Polaris with log LX = 28.89 erg s-1 (0.3-8 keV) and kT = 0.6 keV. A spectrum this soft could come from either the supergiant or the dwarf, as shown by comparable coronal stars. Two resolved low-mass visual companions, "C" and "D," are not physical members of the system based on the lack of X-rays (indicating an age older than the Cepheid) and inconsistent proper motions. Polaris B is not an X-ray source, consistent with its early F spectral type, and probably does not have a lower mass companion itself. A possible more distant member is identified, and an additional less plausible one. This provides a complete census of companions out to 0.1 pc covering a mass ratio range of an order of magnitude and a ΔV of nearly 15 mag. Based on observations made with the NASA Chandra Satellite.

  9. Chandra resolves the T Tauri binary system RW Aur

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Stephen L. [CASA, University of Colorado, Boulder, CO 80309-0389 (United States); Güdel, Manuel, E-mail: stephen.skinner@colorado.edu, E-mail: manuel.guedel@univie.ac.at [Department of Astrophysics, University of Vienna, Türkenschanzstr. 17, A-1180 Vienna (Austria)

    2014-06-20

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

  10. Chandra Sees Shape of Universe During Formative, Adolescent Years

    Science.gov (United States)

    2003-03-01

    Scientists using NASA's Chandra X-ray Observatory have taken a snapshot of the adolescent universe from about five billion years ago when the familiar web-like structure of galaxy chains and voids first emerged. The observation reveals distant and massive galaxies dotting the sky, clustered together under the gravitational attraction of deep, unseen pockets of dark matter. This provides important clues of how the universe matured from its chaotic beginnings to its elegant structure we see today. These results are presented today in a press conference at the meeting of the High Energy Astrophysics Division of the American Astronomical Society at Mt. Tremblant, Quebec. "Piece by piece, we are assembling a photo album of the universe through the ages," said Yuxuan Yang, a doctorate candidate at the University of Maryland, College Park, who conducted the analysis. "Last month we saw a picture of the infant universe taken with the Wilkinson Microwave Anisotropy Probe. Now we can add a snapshot of its adolescence." The Chandra observation traced a patch of sky known as the Lockman Hole in the constellation Ursa Major (containing the Big Dipper). Chandra saw a rich density of active galaxies, seven times denser than what has been detected in previous optical and radio surveys at similar distances. This provides the clearest picture yet at the large-scale structure of the universe at such distances (and age), according to Dr. Richard Mushotzky of NASA Goddard Space Flight Center in Greenbelt, Md., who led the observation. Lockman Hole JPEG, TIFF, PS An image that has been "blurred" to allow better view of the structures outlined by the X-ray sources. The color represents the spectra of the AGN. The red color indicates the sources on average radiates at longer wavelength while green and blue colors indicates the sources radiates at shorter wavelength. The Green and blue regions appear to form a wall, or shows more lumpiness than the "red" sources. If one could capture the

  11. Hard-x-ray phase-difference microscopy with a low-brilliance laboratory x-ray source

    International Nuclear Information System (INIS)

    Kuwabara, Hiroaki; Yashiro, Wataru; Harasse, Sebastien; Momose, Atsushi; Mizutani, Haruo

    2011-01-01

    We have developed a hard-X-ray phase-imaging microscopy method using a low-brilliance X-ray source. The microscope consists of a sample, a Fresnel zone plate, a transmission grating, and a source grating creating an array of mutually incoherent X-ray sources. The microscope generates an image exhibiting twin features of the sample with opposite signs separated by a distance, which is processed to generate a phase image. The method is quantitative even for non-weak-phase objects that are difficult to be quantitatively examined by the widely used Zernike phase-contrast microscopy, and it has potentially broad applications in the material and biological science fields. (author)

  12. A high spatial resolution X-ray and Hα study of hot gas in the halos of star-forming disk galaxies -- testing feedback models

    Science.gov (United States)

    Strickland, D. K.; Heckman, T. M.; Colbert, E. J. M.; Hoopes, C. G.; Weaver, K. A.

    2002-12-01

    We present arcsecond resolution Chandra X-ray and ground-based optical Hα imaging of a sample of ten edge-on star-forming disk galaxies (seven starburst and three ``normal'' spiral galaxies), a sample which covers the full range of star-formation intensity found in disk galaxies. The X-ray observations make use of the unprecented spatial resolution of the Chandra X-ray observatory to robustly remove X-ray emission from point sources, and hence obtain the X-ray properties of the diffuse thermal emission alone. This data has been combined with existing, comparable-resolution, ground-based Hα imaging. We compare these empirically-derived diffuse X-ray properties with various models for the generation of hot gas in the halos of star-forming galaxies: supernova feedback-based models (starburst-driven winds, galactic fountains), cosmologically-motivated accretion of the IGM and AGN-driven winds. SN feedback models best explain the observed diffuse X-ray emission. We then use the data to test basic, but fundamental, aspects of wind and fountain theories, e.g. the critical energy required for disk "break-out." DKS is supported by NASA through Chandra Postdoctoral Fellowship Award Number PF0-10012.

  13. Planetary Protection: X-ray Super-Flares Aid Formation of "Solar Systems"

    Science.gov (United States)

    2005-05-01

    New results from NASA's Chandra X-ray Observatory imply that X-ray super-flares torched the young Solar System. Such flares likely affected the planet-forming disk around the early Sun, and may have enhanced the survival chances of Earth. By focusing on the Orion Nebula almost continuously for 13 days, a team of scientists used Chandra to obtain the deepest X-ray observation ever taken of this or any star cluster. The Orion Nebula is the nearest rich stellar nursery, located just 1,500 light years away. These data provide an unparalleled view of 1400 young stars, 30 of which are prototypes of the early Sun. The scientists discovered that these young suns erupt in enormous flares that dwarf - in energy, size, and frequency -- anything seen from the Sun today. Illustration of Large Flares Illustration of Large Flares "We don't have a time machine to see how the young Sun behaved, but the next best thing is to observe Sun-like stars in Orion," said Scott Wolk of Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "We are getting a unique look at stars between one and 10 million years old - a time when planets form." A key result is that the more violent stars produce flares that are a hundred times as energetic as the more docile ones. This difference may specifically affect the fate of planets that are relatively small and rocky, like the Earth. "Big X-ray flares could lead to planetary systems like ours where Earth is a safe distance from the Sun," said Eric Feigelson of Penn State University in University Park, and principal investigator for the international Chandra Orion Ultradeep Project. "Stars with smaller flares, on the other hand, might end up with Earth-like planets plummeting into the star." Animation of X-ray Flares from a Young Sun Animation of X-ray Flares from a "Young Sun" According to recent theoretical work, X-ray flares can create turbulence when they strike planet-forming disks, and this affects the position of rocky planets as they

  14. Temporal characteristic analysis of laser-modulated pulsed X-ray source for space X-ray communication

    Science.gov (United States)

    Hang, Shuang; Liu, Yunpeng; Li, Huan; Tang, Xiaobin; Chen, Da

    2018-04-01

    X-ray communication (XCOM) is a new communication type and is expected to realize high-speed data transmission in some special communication scenarios, such as deep space communication and blackout communication. This study proposes a high-speed modulated X-ray source scheme based on the laser-to-X-ray conversion. The temporal characteristics of the essential components of the proposed laser-modulated pulsed X-ray source (LMPXS) were analyzed to evaluate its pulse emission performance. Results show that the LMPXS can provide a maximum modulation rate up to 100 Mbps which is expected to significantly improve the data rate of XCOM.

  15. 21 CFR 872.1810 - Intraoral source x-ray system.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1810 Intraoral source x-ray system. (a... structures. The x-ray source (a tube) is located inside the mouth. This generic type of device may include... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraoral source x-ray system. 872.1810 Section...

  16. Combined optic system based on polycapillary X-ray optics and single-bounce monocapillary optics for focusing X-rays from a conventional laboratory X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xuepeng; Liu, Zhiguo [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi, E-mail: stx@bnu.edu.cn [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Yi, Longtao; Sun, Weiyuan; Li, Fangzuo; Jiang, Bowen [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma, Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Ding, Xunliang [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2015-12-01

    Two combined optic systems based on polycapillary X-ray optics and single-bounce monocapillary optics (SBMO) were designed for focusing the X-rays from a conventional laboratory X-ray source. One was based on a polycapillary focusing X-ray lens (PFXRL) and a single-bounce ellipsoidal capillary (SBEC), in which the output focal spot with the size of tens of micrometers of the PFXRL was used as the “virtual” X-ray source for the SBEC. The other system was based on a polycapillary parallel X-ray lens (PPXRL) and a single-bounce parabolic capillary (SBPC), in which the PPXRL transformed the divergent X-ray beam from an X-ray source into a quasi-parallel X-ray beam with the divergence of sever milliradians as the incident illumination of the SBPC. The experiment results showed that the combined optic systems based on PFXRL and SBEC with a Mo rotating anode X-ray generator with the focal spot with a diameter of 300 μm could obtain a focal spot with the total gain of 14,300 and focal spot size of 37.4 μm, and the combined optic systems based on PPXRL and SBPC with the same X-ray source mentioned above could acquire a focal spot with the total gain of 580 and focal spot size of 58.3 μm, respectively. The two combined optic systems have potential applications in micro X-ray diffraction, micro X-ray fluorescence, micro X-ray absorption near edge structure, full field X-ray microscopes and so on.

  17. X-ray and. gamma. -ray sources: a comparison of their characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Freund, A K [Institut Max von Laue - Paul Langevin, 38 - Grenoble (France)

    1979-11-01

    A comparison of the various source characteristics, in particular the available fluxes of radiation in the X-ray/..gamma..-ray region from (1) high power rotary anode X-ray generators, (2) radioactive ..gamma..-ray sources and (3) high energy electron storage rings is presented. Some of the specific characteristics and possible applications of synchrotron radiation as a source are discussed in detail, together with problems associated with the monochromatization of the continuous radiation in the X-ray/..gamma..-ray region. The new high energy machines PEP at Stanford, the 8 GeV storage ring CESR at Cornell and the PETRA storage ring in Hamburg, which will soon come into operation provide a spectrum of high intensity radiation reaching well above h..gamma..sub(photon)=100 keV. The possibilities of using ondulators (wigglers), and laser-electron scattering for constructing high repetition rate tunable ..gamma..-ray sources are also discussed. Finally the potentials of using the powerful spontaneous emission of ..gamma..-quanta by relativistic channeled particles are mentioned.

  18. CHANDRA DETECTION OF A NEW DIFFUSE X-RAY COMPONENT FROM THE GLOBULAR CLUSTER 47 TUCANAE

    Energy Technology Data Exchange (ETDEWEB)

    Wu, E. M. H.; Cheng, K. S. [Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong); Hui, C. Y. [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of); Kong, A. K. H.; Tam, P. H. T. [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China); Dogiel, V. A., E-mail: cyhui@cnu.ac.kr [I. E. Tamm Theoretical Physics Division of P. N. Lebedev Institute of Physics, Leninskii pr. 53, 119991 Moscow (Russian Federation)

    2014-06-20

    In re-analyzing the archival Chandra data of the globular cluster 47 Tucanae, we have detected a new diffuse X-ray emission feature within the half-mass radius of the cluster. The spectrum of the diffuse emission can be described by a power-law model plus a plasma component with photon index Γ ∼ 1.0 and plasma temperature kT ∼ 0.2 keV. While the thermal component is apparently uniform, the non-thermal contribution falls off exponentially from the core. The observed properties could possibly be explained in the context of multiple shocks resulting from the collisions among the stellar wind in the cluster and the inverse Compton scattering between the pulsar wind and the relic photons.

  19. Feasibility study on X-ray source with pinhole imaging method

    International Nuclear Information System (INIS)

    Qiu Rui; Li Junli

    2007-01-01

    In order to verify the feasibility of study on X-ray source with pinhole imaging method, and optimize the design of X-ray pinhole imaging system, an X-ray pinhole imaging equipment was set up. The change of image due to the change of the position and intensity of X-ray source was estimated with mathematical method and validated with experiment. The results show that the change of the spot position and gray of the spot is linearly related with the change of the position and intensity of X-ray source, so it is feasible to study X-ray source with pinhole imaging method in this application. The results provide some references for the design of X-ray pinhole imaging system. (authors)

  20. X-ray pulsars in nearby irregular galaxies

    Science.gov (United States)

    Yang, Jun

    2018-01-01

    The Small Magellanic Cloud (SMC), Large Magellanic Cloud (LMC) and Irregular Galaxy IC 10 are valuable laboratories to study the physical, temporal and statistical properties of the X-ray pulsar population with multi-satellite observations, in order to probe fundamental physics. The known distance of these galaxies can help us easily categorize the luminosity of the pulsars and their age difference can be helpful for for studying the origin and evolution of compact objects. Therefore, a complete archive of 116 XMM-Newton PN, 151 Chandra (Advanced CCD Imaging Spectrometer) ACIS, and 952 RXTE PCA observations for the pulsars in the Small Magellanic Cloud (SMC) were collected and analyzed, along with 42 XMM-Newton and 30 Chandra observations for the Large Magellanic Cloud, spanning 1997-2014. From a sample of 67 SMC pulsars we generate a suite of products for each pulsar detection: spin period, flux, event list, high time-resolution light-curve, pulse-profile, periodogram, and X-ray spectrum. Combining all three satellites, I generated complete histories of the spin periods, pulse amplitudes, pulsed fractions and X-ray luminosities. Many of the pulsars show variations in pulse period due to the combination of orbital motion and accretion torques. Long-term spin-up/down trends are seen in 28/25 pulsars respectively, pointing to sustained transfer of mass and angular momentum to the neutron star on decadal timescales. The distributions of pulse detection and flux as functions of spin period provide interesting findings: mapping boundaries of accretion-driven X-ray luminosity, and showing that fast pulsars (P<10 s) are rarely detected, which yet are more prone to giant outbursts. In parallel we compare the observed pulse profiles to our general relativity (GR) model of X-ray emission in order to constrain the physical parameters of the pulsars.In addition, we conduct a search for optical counterparts to X-ray sources in the local dwarf galaxy IC 10 to form a comparison

  1. Heavy X-ray obscuration in the most luminous galaxies discovered by WISE

    Science.gov (United States)

    Vito, F.; Brandt, W. N.; Stern, D.; Assef, R. J.; Chen, C.-T. J.; Brightman, M.; Comastri, A.; Eisenhardt, P.; Garmire, G. P.; Hickox, R.; Lansbury, G.; Tsai, C.-W.; Walton, D. J.; Wu, J. W.

    2018-03-01

    Hot dust-obscured galaxies (DOGs) are hyperluminous (L8-1000 μm > 1013 L⊙) infrared galaxies with extremely high (up to hundreds of K) dust temperatures. The sources powering both their extremely high luminosities and dust temperatures are thought to be deeply buried and rapidly accreting supermassive black holes (SMBHs). Hot DOGs could therefore represent a key evolutionary phase in which the SMBH growth peaks. X-ray observations can be used to study their obscuration levels and luminosities. In this work, we present the X-ray properties of the 20 most luminous (Lbol ≳ 1014 L⊙) known hot DOGs at z = 2-4.6. Five of them are covered by long-exposure (10-70 ks) Chandra and XMM-Newton observations, with three being X-ray detected, and we study their individual properties. One of these sources (W0116-0505) is a Compton-thick candidate, with column density NH = (1.0-1.5) × 1024 cm-2 derived from X-ray spectral fitting. The remaining 15 hot DOGs have been targeted by a Chandra snapshot (3.1 ks) survey. None of these 15 are individually detected; therefore, we applied a stacking analysis to investigate their average emission. From hardness ratio analysis, we constrained the average obscuring column density and intrinsic luminosity to be log NH (cm-2) > 23.5 and LX ≳ 1044 erg s-1, which are consistent with results for individually detected sources. We also investigated the LX-L6 μm and LX-Lbol relations, finding hints that hot DOGs are typically X-ray weaker than expected, although larger samples of luminous obscured quasi-stellar objects are needed to derive solid conclusions.

  2. 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...

  3. Giant Rapid X-ray Flares in Extragalactic Globular Clusters

    Science.gov (United States)

    Irwin, Jimmy

    2018-01-01

    There is only one known class of non-destructive, highly energetic astrophysical object in the Universe whose energy emission varies by more than a factor of 100 on time scales of less than a minute -- soft gamma repeaters/anomalous X-ray pulsars, whose flares are believed to be caused by the energy release from the cracking of a neutron star's surface by very strong magnetic fields. All other known violent, rapid explosions, including gamma-ray bursts and supernovae, are believed to destroy the object in the process. Here, we report the discovery of a second class of non-destructive, highly energetic rapidly flaring X-ray object located within two nearby galaxies with fundamentally different properties than soft gamma repeaters/anomalous X-ray pulsars. One source is located within a suspected globular cluster of the host galaxy and flared one time, while the other source is located in either a globular cluster of the host galaxy or the core of a stripped dwarf companion galaxy that flared on six occasions over a seven year time span. When not flaring, the sources appear as normal accreting neutron star or black hole X-ray binaries, indicating that the flare event does not significantly disrupt the host system. While the nature of these sources is still unclear, the discovery of these sources in decade-old archival Chandra X-ray Observatory data illustrates the under-utilization of X-ray timing as a means to discover new classes of explosive events in the Universe.

  4. Simple, compact, high brightness source for x-ray lithography and x-ray radiography

    International Nuclear Information System (INIS)

    Hawryluk, A.M.

    1986-01-01

    A simple, compact, high brightness x-ray source has recently been built. This source utilizes a commercially available, cylindrical geometry electron beam evaporator, which has been modified to enhance the thermal cooling to the anode. Cooling is accomplished by using standard, low-conductivity laboratory water, with an inlet pressure of less than 50 psi, and a flow rate of approx.0.3 gal/min. The anode is an inverted cone geometry for efficient cooling. The x-ray source has a measured sub-millimeter spot size (FWHM). The anode has been operated at 1 KW e-beam power (10 KV, 100 ma). Higher operating levels will be investigated. A variety of different x-ray lines can be obtained by the simple interchange of anodes of different materials. Typical anodes are made from easily machined metals, or materials which are vacuum deposited onto a copper anode. Typically, a few microns of material is sufficient to stop 10 KV electrons without significantly decreasing the thermal conductivity through the anode. The small size and high brightness of this source make it useful for step and repeat exposures over several square centimeter areas, especially in a research laboratory environment. For an aluminum anode, the estimated Al-K x-ray flux at 10 cms from the source is 70 μW/cm 2

  5. Flash X-Ray (FXR) Accelerator Optimization Electronic Time-Resolved Measurement of X-Ray Source Size

    International Nuclear Information System (INIS)

    Jacob, J; Ong, M; Wargo, P

    2005-01-01

    Lawrence Livermore National Laboratory (LLNL) is currently investigating various approaches to minimize the x-ray source size on the Flash X-Ray (FXR) linear induction accelerator in order to improve x-ray flux and increase resolution for hydrodynamic radiography experiments. In order to effectively gauge improvements to final x-ray source size, a fast, robust, and accurate system for measuring the spot size is required. Timely feedback on x-ray source size allows new and improved accelerator tunes to be deployed and optimized within the limited run-time constraints of a production facility with a busy experimental schedule; in addition, time-resolved measurement capability allows the investigation of not only the time-averaged source size, but also the evolution of the source size, centroid position, and x-ray dose throughout the 70 ns beam pulse. Combined with time-resolved measurements of electron beam parameters such as emittance, energy, and current, key limiting factors can be identified, modeled, and optimized for the best possible spot size. Roll-bar techniques are a widely used method for x-ray source size measurement, and have been the method of choice at FXR for many years. A thick bar of tungsten or other dense metal with a sharp edge is inserted into the path of the x-ray beam so as to heavily attenuate the lower half of the beam, resulting in a half-light, half-dark image as seen downstream of the roll-bar; by measuring the width of the transition from light to dark across the edge of the roll-bar, the source size can be deduced. For many years, film has been the imaging medium of choice for roll-bar measurements thanks to its high resolution, linear response, and excellent contrast ratio. Film measurements, however, are fairly cumbersome and require considerable setup and analysis time; moreover, with the continuing trend towards all-electronic measurement systems, film is becoming increasingly difficult and expensive to procure. Here, we shall

  6. Chandra Source Catalog: User Interfaces

    Science.gov (United States)

    Bonaventura, Nina; Evans, I. N.; Harbo, P. N.; Rots, A. H.; Tibbetts, M. S.; Van Stone, D. W.; Zografou, P.; Anderson, C. S.; Chen, J. C.; Davis, J. E.; Doe, S. M.; Evans, J. D.; Fabbiano, G.; Galle, E.; Gibbs, D. G.; Glotfelty, K. J.; Grier, J. D.; Hain, R.; Hall, D. M.; He, X.; Houck, J. C.; Karovska, M.; Lauer, J.; McCollough, M. L.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Nowak, M. A.; Plummer, D. A.; Primini, F. A.; Refsdal, B. L.; Siemiginowska, A. L.; Sundheim, B. A.; Winkelman, S. L.

    2010-03-01

    The CSCview data mining interface is available for browsing the Chandra Source Catalog (CSC) and downloading tables of quality-assured source properties and data products. Once the desired source properties and search criteria are entered into the CSCview query form, the resulting source matches are returned in a table along with the values of the requested source properties for each source. (The catalog can be searched on any source property, not just position.) At this point, the table of search results may be saved to a text file, and the available data products for each source may be downloaded. CSCview save files are output in RDB-like and VOTable format. The available CSC data products include event files, spectra, lightcurves, and images, all of which are processed with the CIAO software. CSC data may also be accessed non-interactively with Unix command-line tools such as cURL and Wget, using ADQL 2.0 query syntax. In fact, CSCview features a separate ADQL query form for those who wish to specify this type of query within the GUI. Several interfaces are available for learning if a source is included in the catalog (in addition to CSCview): 1) the CSC interface to Sky in Google Earth shows the footprint of each Chandra observation on the sky, along with the CSC footprint for comparison (CSC source properties are also accessible when a source within a Chandra field-of-view is clicked); 2) the CSC Limiting Sensitivity online tool indicates if a source at an input celestial location was too faint for detection; 3) an IVOA Simple Cone Search interface locates all CSC sources within a specified radius of an R.A. and Dec.; and 4) the CSC-SDSS cross-match service returns the list of sources common to the CSC and SDSS, either all such sources or a subset based on search criteria.

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

    DEFF Research Database (Denmark)

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

    1994-01-01

    The undulator X-ray source is an ideal source for many applications: the beam is brilliant, highly collimated in all directions, quasi-monochromatic, pulsed and linearly polarized. Such a precious source can feed several independently operated instruments by utilizing a downstream series of X......-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...

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

    International Nuclear Information System (INIS)

    Mauche, Christopher W.

    2009-01-01

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

  9. X-ray Studies of Unidentified Galactic TeV Gamma-ray Sources

    Science.gov (United States)

    Pühlhofer, Gerd

    2009-05-01

    Many of the recently discovered Galactic TeV sources remain unidentified to date. A large fraction of the sources is possibly associated with relic pulsar wind nebula (PWN) systems. One key question here is the maximum energy (beyond TeV) attained in the compact PWNe. Hard X-ray emission can trace those particles, but current non-focussing X-ray instruments above 10 keV have difficulties to deconvolve the hard pulsar spectrum from its surrounding nebula. Some of the new TeV sources are also expected to originate from middle-aged and possibly even from old supernova remnants (SNR). But no compelling case for such an identification has been found yet. In established young TeV-emitting SNRs, X-ray imaging above 10 keV could help to disentangle the leptonic from the hadronic emission component in the TeV shells, if secondary electrons produced in hadronic collisions can be effectively detected. As SNRs get older, the high energy electron component is expected to fade away. This may allow to verify the picture through X-ray spectral evolution of the source population. Starting from the lessons we have learned so far from X-ray follow-up observations of unidentified TeV sources, prospects for Simbol-X to resolve open questions in this field will be discussed.

  10. X-ray Studies of Unidentified Galactic TeV Gamma-ray Sources

    International Nuclear Information System (INIS)

    Puehlhofer, Gerd

    2009-01-01

    Many of the recently discovered Galactic TeV sources remain unidentified to date. A large fraction of the sources is possibly associated with relic pulsar wind nebula (PWN) systems. One key question here is the maximum energy (beyond TeV) attained in the compact PWNe. Hard X-ray emission can trace those particles, but current non-focussing X-ray instruments above 10 keV have difficulties to deconvolve the hard pulsar spectrum from its surrounding nebula.Some of the new TeV sources are also expected to originate from middle-aged and possibly even from old supernova remnants (SNR). But no compelling case for such an identification has been found yet. In established young TeV-emitting SNRs, X-ray imaging above 10 keV could help to disentangle the leptonic from the hadronic emission component in the TeV shells, if secondary electrons produced in hadronic collisions can be effectively detected. As SNRs get older, the high energy electron component is expected to fade away. This may allow to verify the picture through X-ray spectral evolution of the source population.Starting from the lessons we have learned so far from X-ray follow-up observations of unidentified TeV sources, prospects for Simbol-X to resolve open questions in this field will be discussed.

  11. Dissecting Diffuse X-ray Emission in 30 Doradus with T-ReX

    Science.gov (United States)

    Townsley, Leisa K.; Broos, Patrick

    2017-08-01

    30 Doradus (the Tarantula Nebula) offers us a microscope on starburst astrophysics, having endured 25 Myrs of the birth and death of the most massive stars known. Across 30 Dor's 250-pc extent, stellar winds and supernovae have carved its ISM into an amazing display of arcs, pillars, and bubbles. For over 40 years, we have also known that 30 Dor is a bright X-ray emitter, so its familiar stars and cold ISM structures suffer irradiation by multi-million-degree plasmas. The 2-Ms Chandra X-ray Visionary Project ``The Tarantula -- Revealed by X-rays'' (T-ReX) exploits Chandra's fine spatial resolution and the ACIS-I field of view to study ISM interfaces on 1--10 pc scales across the entire 30 Dor complex. Here we give preliminary results from ongoing analyses of these data, focusing on the diffuse X-ray emission. Massive star winds and cavity supernovae over the millenia have contributed to a broad mix of X-ray-emitting plasmas and absorbing columns, showing that 30 Dor's hot ISM is just as complex and confusing as that seen at colder temperatures.

  12. X-ray Binaries in the Central Region of M31

    Science.gov (United States)

    Trudolyubov, Sergey P.; Priedhorsky, W. C.; Cordova, F. A.

    2006-09-01

    We present the results of the systematic survey of X-ray sources in the central region of M31 using the data of XMM-Newton observations. The spectral properties and variability of 124 bright X-ray sources were studied in detail. We found that more than 80% of sources observed in two or more observations show significant variability on the time scales of days to years. At least 50% of the sources in our sample are spectrally variable. The fraction of variable sources in our survey is much higher than previously reported from Chandra survey of M31, and is remarkably close to the fraction of variable sources found in M31 globular cluster X-ray source population. We present spectral distribution of M31 X-ray sources, based on the spectral fitting with a power law model. The distribution of spectral photon index has two main peaks at 1.8 and 2.3, and shows clear evolution with source luminosity. Based on the similarity of the properties of M31 X-ray sources and their Galactic counterparts, we expect most of X-ray sources in our sample to be accreting binary systems with neutron star and black hole primaries. Combining the results of X-ray analysis (X-ray spectra, hardness-luminosity diagrams and variability) with available data at other wavelengths, we explore the possibility of distinguishing between bright neutron star and black hole binary systems, and identify 7% and 25% of sources in our sample as a probable black hole and neutron star candidates. Finally, we compare the M31 X-ray source population to the source populations of normal galaxies of different morphological type. Support for this work was provided through NASA Grant NAG5-12390. Part of this work was done during a summer workshop ``Revealing Black Holes'' at the Aspen Center for Physics, S. T. is grateful to the Center for their hospitality.

  13. A portable x-ray source and method for radiography

    International Nuclear Information System (INIS)

    Golovanivsky, K.S.

    1996-01-01

    A portable x-ray source that produces a sufficient x-ray flux to produce high quality x-ray images on x-ray films. The source includes a vacuum chamber filled with a heavy atomic weight gas at low pressure and an x-ray emitter. The chamber is in a magnetic field and an oscillating electric field and generates electron cyclotron resonance (ECR) plasma having a ring of energetic electrons inside the chamber. The electrons bombard the x-ray emitter which in turn produces x-ray. A pair of magnetic members generate an axisymmetric magnetic mirror trap inside the chamber. The chamber may be nested within a microwave resonant cavity and between the magnets or the chamber and the microwave cavity may be a single composite structure. (author)

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

    Science.gov (United States)

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

    2016-07-01

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

  15. Characteristics of a molybdenum X-pinch X-ray source as a probe source for X-ray diffraction studies

    International Nuclear Information System (INIS)

    Zucchini, F.; Chauvin, C.; Combes, P.; Sol, D.; Loyen, A.; Roques, B.; Grunenwald, J.; Bland, S. N.

    2015-01-01

    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

  16. CIAO: A Modern Data Analysis System for X-Ray Astronomy

    Science.gov (United States)

    Fruscione, Antonella

    2017-08-01

    It is now eighteen years after launch and Chandra continues to produce spectacular results!A portion of the success is to be attributed to the data analysis software CIAO (Chandra Interactive Analysis of Observations) that the Chandra X-Ray Center (CXC) continues to improve and release year after year.CIAO is downloaded more than 1200 times a year and it is used by a wide variety of users around the world: from novice to experienced X-ray astronomers, high school, undergraduate and graduate students, archival users (many new to X-ray or Chandra data), users with extensive resources and others from smaller countries and institutions.The scientific goals and kinds of datasets and analysis cover a wide range: observations spanning from days to years, different instrument configurations and different kinds of targets, from pointlike stars and quasars, to fuzzy galaxies and clusters, to moving solar objects. These different needs and goals require a variety of specialized software and careful and detailed documentation which is what the CIAO software provides. In general, we strive to build a software system which is easy for beginners, yet powerful for advanced users.The complexity of the Chandra data require a flexible data analysis system which provides an environment where the users can apply our tools, but can also explore and construct their own applications. The main purpose of this talk is to present CIAO as a modern data analysis system for X-ray data analysis.CIAO has grown tremendously over the years and we will highlight (a) the most recent advancements with a particular emphasis on the newly developed high-level scripts which simplify the analysis steps for the most common cases making CIAO more accessible to all users - including beginners and users who are not X-ray astronomy specialists, (b) the python-based Sherpa modelling and fitting application and the new stand-alone version openly developed and distributed on Github and (c) progress on methods to

  17. Oxygen, Neon, and Iron X-Ray Absorption in the Local Interstellar Medium

    Science.gov (United States)

    Gatuzz, Efrain; Garcia, Javier; Kallman, Timothy R.; Mendoza, Claudio

    2016-01-01

    We present a detailed study of X-ray absorption in the local interstellar medium by analyzing the X-ray spectra of 24 galactic sources obtained with the Chandra High Energy Transmission Grating Spectrometer and the XMM-Newton Reflection Grating Spectrometer. Methods. By modeling the continuum with a simple broken power-law and by implementing the new ISMabs X-ray absorption model, we have estimated the total H, O, Ne, and Fe column densities towards the observed sources. Results. We have determined the absorbing material distribution as a function of source distance and galactic latitude longitude. Conclusions. Direct estimates of the fractions of neutrally, singly, and doubly ionized species of O, Ne, and Fe reveal the dominance of the cold component, thus indicating an overall low degree of ionization. Our results are expected to be sensitive to the model used to describe the continuum in all sources.

  18. X-ray photoelectron microscope with a compact x-ray source generated by line-focused laser irradiation

    International Nuclear Information System (INIS)

    Yamaguchi, N.; Okamoto, Y.; Hara, T.; Takahashi, Z.; Nishimura, Y.; Sakata, A.; Watanabe, K.; Azuma, H.

    2004-01-01

    Full text: A laboratory-sized microscopic system of x-ray photoelectrons has been developing using a compact x-ray source produced by line-focused laser irradiation. The system is a scanning type photoelectron microscope where x-ray beam is micro-focused via a Schwartzschild optics. A compact laser-plasma x-ray source has been developed with a YAG laser system, a line-focus lens system, a tape-target driving system and a debris prevention system, that was operated at repetition rate of 10 Hz or 50 Hz. X-rays were delivered along line plasma whose length was 0.6 to 11 mm with higher intensity than that from a point-focused source. Because the transition line of Al V (13.1 nm) was prominent in the soft x-ray spectrum when the Al tape target irradiated at the lower power density of 10 11 W/cm 2 , the 13.1 nm x-ray was used as an excitation source. The Schwartzschild optics was set on the beamline at a distance about 1 m from the source, which was coated with Mo/Si multilayers for 13.1 nm x-ray. The designed demagnification is 224 that was confirmed in the previous experiment. Therefore, an x-ray micro spot of sub-micron size can be formed on a sample surface when the source size is less than about 0.2 mm. Samples were set on a two-axis high-precision piezo stage mounted to a four-axis manipulator. The electron energy analyzer was a spherical capacitor analyzer with mean diameter of 279.4 mm. The electron detector was a microchannel plate (MCP) with a phosphor screen and the optical image of electrons on the exit plane of the analyzer was taken and recorded by using an ultra low dark noise CCD camera, that was suited for detection of vast photoelectrons excited by x-ray pulse of ns-order duration. We performed spatial resolution test measurements by using a GaAs wafer coated with photo-resist that formed a stripe pattern. The spatial resolution less than 3 micron has been obtained from the variation of As 3d electron intensity along the position of the GaAs sample

  19. Classification of X-ray sources in the direction of M31

    Science.gov (United States)

    Vasilopoulos, G.; Hatzidimitriou, D.; Pietsch, W.

    2012-01-01

    M31 is our nearest spiral galaxy, at a distance of 780 kpc. Identification of X-ray sources in nearby galaxies is important for interpreting the properties of more distant ones, mainly because we can classify nearby sources using both X-ray and optical data, while more distant ones via X-rays alone. The XMM-Newton Large Project for M31 has produced an abundant sample of about 1900 X-ray sources in the direction of M31. Most of them remain elusive, giving us little signs of their origin. Our goal is to classify these sources using criteria based on properties of already identified ones. In particular we construct candidate lists of high mass X-ray binaries, low mass X-ray binaries, X-ray binaries correlated with globular clusters and AGN based on their X-ray emission and the properties of their optical counterparts, if any. Our main methodology consists of identifying particular loci of X-ray sources on X-ray hardness ratio diagrams and the color magnitude diagrams of their optical counterparts. Finally, we examined the X-ray luminosity function of the X-ray binaries populations.

  20. Medical X-ray sources now and for the future

    Science.gov (United States)

    Behling, Rolf

    2017-11-01

    This paper focuses on the use of X-rays in their largest field of application: medical diagnostic imaging and image-guided therapy. For this purpose, vacuum electronics in the form of X-ray tubes as the source of bremsstrahlung (braking radiation) have been the number one choice for X-ray production in the range of photon energies between about 16 keV for mammography and 150 keV for general radiography. Soft tissue on one end and bony structures on the other are sufficiently transparent and the contrast delivered by difference of absorption is sufficiently high for this spectral range. The dominance of X-ray tubes holds even more than 120 years after Conrad Roentgen's discovery of the bremsstrahlung mechanism. What are the specifics of current X-ray tubes and their medical diagnostic applications? How may the next available technology at or beyond the horizon look like? Can we hope for substantial game changers? Will flat panel sources, less expensive X-ray "LED's", compact X-ray Lasers, compact synchrotrons or equivalent X-ray sources appear in medical diagnostic imaging soon? After discussing the various modalities of imaging systems and their sources of radiation, this overview will briefly touch on the physics of bremsstrahlung generation, key characteristics of X-ray tubes, and material boundary conditions, which restrict performance. It will discuss the deficits of the bremsstrahlung technology and try to sketch future alternatives and their prospects of implementation in medical diagnostics.

  1. Adjustable Grazing-Incidence X-Ray Optics

    Science.gov (United States)

    O'Dell, Stephen L.; Reid, Paul B.

    2015-01-01

    With its unique subarcsecond imaging performance, NASA's Chandra X-ray Observatory illustrates the importance of fine angular resolution for x-ray astronomy. Indeed, the future of x-ray astronomy relies upon x-ray telescopes with comparable angular resolution but larger aperture areas. Combined with the special requirements of nested grazing-incidence optics, mass, and envelope constraints of space-borne telescopes render such advances technologically and programmatically challenging. The goal of this technology research is to enable the cost-effective fabrication of large-area, lightweight grazing-incidence x-ray optics with subarcsecond resolution. Toward this end, the project is developing active x-ray optics using slumped-glass mirrors with thin-film piezoelectric arrays for correction of intrinsic or mount-induced distortions.

  2. Simultaneous Chandra and NuSTAR Observations of the Highly Obscured AGN Candidate in NGC660.

    Science.gov (United States)

    Annuar, Ady

    2014-09-01

    We are using NuSTAR to undertake a detailed investigation of the obscured AGN population at D<15Mpc. Our latest target is NGC660 where the presence of an AGN has been ambiguous. However, recently it was observed to undergo a radio outburst which reveals a bright continuum source (Argo et al. 2015), coincident with Chandra 2-8 keV emission from one of the three point sources near the nucleus (<5"). This confirms and pinpoints the X-ray position of the AGN. Comparisons of the Chandra flux with the radio emission and other multiwavelength luminosity indicators indicate that the X-ray flux is suppressed, suggesting that it is absorbed by a high column of gas. A NuSTAR observation for this object has been scheduled as part of our program. The requested Chandra observation is essential to unambiguously constrain the AGN and isolate it from other sources at <8 keV. When combined with NuSTAR, we will then be able to accurately characterise the 0.5-30 keV spectrum of the AGN for the first time.

  3. A Deep Chandra ACIS Study of NGC 4151. I. The X-ray Morphology of the 3 kpc Diameter Circum-nuclear Region and Relation to the Cold Interstellar Medium

    Science.gov (United States)

    Wang, Junfeng; Fabbiano, Giuseppina; Risaliti, Guido; Elvis, Martin; Karovska, Margarita; Zezas, Andreas; Mundell, Carole G.; Dumas, Gaelle; Schinnerer, Eva

    2011-03-01

    We report on the imaging analysis of ~200 ks sub-arcsecond resolution Chandra Advanced CCD Imaging Spectrometer (ACIS-S) observations of the nearby Seyfert 1 galaxy NGC 4151. Bright, structured soft X-ray emission is observed to extend from 30 pc to 1.3 kpc in the southwest from the nucleus, much farther than seen in earlier X-ray studies. The terminus of the northeastern X-ray emission is spatially coincident with a CO gas lane, where the outflow likely encounters dense gas in the host galactic disk. X-ray emission is also detected outside the boundaries of the ionization cone, which indicates that the gas there is not completely shielded from the nuclear continuum, as would be the case for a molecular torus collimating the bicone. In the central r < 200 pc region, the subpixel processing of the ACIS data recovers the morphological details on scales of <30 pc (<0farcs5) first discovered in Chandra High Resolution Camera images. The X-ray emission is more absorbed toward the boundaries of the ionization cone, as well as perpendicular to the bicone along the direction of a putative torus in NGC 4151. The innermost region where X-ray emission shows the highest hardness ratio is spatially coincident with the near-infrared-resolved H2 emission and dusty spirals we find in an Hubble Space Telescope V - H color image. The agreement between the observed H2 line flux and the value predicted from X-ray-irradiated molecular cloud models supports photo-excitation by X-rays from the active nucleus as the origin of the H2 line, although contribution from UV fluorescence or collisional excitation cannot be ruled out with current data. The discrepancy between the mass of cold molecular gas inferred from recent CO and near-infrared H2 observations may be explained by the anomalous CO abundance in this X-ray-dominated region. The total H2 mass derived from the X-ray observation agrees with the recent measurement by Storchi-Bergmann et al.

  4. Solar and Stellar X-ray Cycles

    Science.gov (United States)

    Martens, P. C. H.; SADE Team

    2004-05-01

    Stern et al. have shown that Yohkoh-SXT full disk X-ray irradiance shows an 11 year cycle with an max/min amplitude ratio of a factor 30. Similar cyclic X-ray variation in Sun-like stars observed by ROSAT and its predecessors is observed in only a few cases and limited to a factor two or three. We will show, by means of detailed bandpass comparisons, that this discrepancy cannot be ascribed to the differences in energy response between SXT and the stellar soft X-ray detectors. Is the Sun exceptional? After centuries of geocentric and heliocentric worldviews we find this a difficult proposition to entertain. But perhaps the Sun is a member of a small class of late-type stars with large amplitudes in their X-ray cycles. The stellar X-ray observations listed in the HEASARC catalog are too sparse to verify this hypothesis. To resolve these and related questions we have proposed a small low-cost stellar X-ray spectroscopic imager originally called SADE to obtain regular time series from late and early-type stars and accretion disks. This instrument is complimentary to the much more advanced Chandra and XMM-Newton observatories, and allows them to focus on those sources that require their full spatial and spectral resolution. We will describe the basic design and spectroscopic capability of SADE and show it meets the mission requirements.

  5. Diagnostic Spectrometers for High Energy Density X-Ray Sources

    International Nuclear Information System (INIS)

    Hudson, L. T.; Henins, A.; Seely, J. F.; Holland, G. E.

    2007-01-01

    A new generation of advanced laser, accelerator, and plasma confinement devices are emerging that are producing extreme states of light and matter that are unprecedented for laboratory study. Examples of such sources that will produce laboratory x-ray emissions with unprecedented characteristics include megajoule-class and ultrafast, ultraintense petawatt laser-produced plasmas; tabletop high-harmonic-generation x-ray sources; high-brightness zeta-pinch and magnetically confined plasma sources; and coherent x-ray free electron lasers and compact inverse-Compton x-ray sources. Characterizing the spectra, time structure, and intensity of x rays emitted by these and other novel sources is critical to assessing system performance and progress as well as pursuing the new and unpredictable physical interactions of interest to basic and applied high-energy-density (HED) science. As these technologies mature, increased emphasis will need to be placed on advanced diagnostic instrumentation and metrology, standard reference data, absolute calibrations and traceability of results.We are actively designing, fabricating, and fielding wavelength-calibrated x-ray spectrometers that have been employed to register spectra from a variety of exotic x-ray sources (electron beam ion trap, electron cyclotron resonance ion source, terawatt pulsed-power-driven accelerator, laser-produced plasmas). These instruments employ a variety of curved-crystal optics, detector technologies, and data acquisition strategies. In anticipation of the trends mentioned above, this paper will focus primarily on optical designs that can accommodate the high background signals produced in HED experiments while also registering their high-energy spectral emissions. In particular, we review the results of recent laboratory testing that explores off-Rowland circle imaging in an effort to reclaim the instrumental resolving power that is increasingly elusive at higher energies when using wavelength

  6. Table-top laser-driven ultrashort electron and X-ray source: the CIBER-X source project

    Science.gov (United States)

    Girardeau-Montaut, Jean-Pierre; Kiraly, Bélà; Girardeau-Montaut, Claire; Leboutet, Hubert

    2000-09-01

    We report on the development of a new laser-driven table-top ultrashort electron and X-ray source, also called the CIBER-X source . X-ray pulses are produced by a three-step process which consists of the photoelectron emission from a thin metallic photocathode illuminated by 16 ps duration laser pulses at 213 nm. The e-gun is a standard Pierce diode electrode type, in which electrons are accelerated by a cw electric field of ˜11 MV/m up to a hole made in the anode. The photoinjector produces a train of 70-80 keV electron pulses of ˜0.5 nC and 20 A peak current at a repetition rate of 10 Hz. The electrons are then transported outside the diode along a path of 20 cm length, and are focused onto a target of thullium by magnetic fields produced by two electromagnetic coils. X-rays are then produced by the impact of electrons on the target. Simulations of geometrical, electromagnetic fields and energetic characteristics of the complete source were performed previously with the assistance of the code PIXEL1 also developed at the laboratory. Finally, experimental electron and X-ray performances of the CIBER-X source as well as its application to very low dose imagery are presented and discussed. source Compacte d' Impulsions Brèves d' Electrons et de Rayons X

  7. Characteristics of hard X-ray double sources in impulsive solar flares

    Science.gov (United States)

    Sakao, T.; Kosugi, T.; Masuda, S.; Yaji, K.; Inda-Koide, M.; Makishima, K.

    1996-01-01

    Imaging observations of solar flare hard X-ray sources with the Hard X-ray Telescope (HXT) aboard the Yohkoh satellite have revealed that hard X-ray emissions (greater than 30 ke V) originate most frequently from double sources. The double sources are located on both sides of the magnetic neutral line, suggesting that the bulk of hard X-rays is emitted from footpoints of flaring magnetic loops. We also found that hard X-rays from the double sources are emitted simultaneously within a fraction of second and that the weaker source tends to be located in the stronger magnetic field region, showing a softer spectrum. Physcial implications on the observed characteristics of the hard X-ray double sources are discussed.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    We performed a Chandra X-ray study of three giant H II regions (GHRs), NGC 5461, NGC 5462, and NGC 5471, in the spiral galaxy M101. The X-ray spectra of the three GHRs all contain a prominent thermal component with a temperature of ∼0.2 keV. In NGC 5461, the spatial distribution of the soft ( 52 erg, is consistent with a hypernova origin. In addition, a bright source in the field of NGC 5462 has been identified as a background active galactic nucleus, instead of a black hole X-ray binary in M101.

  9. NuSTAR Hard X-Ray Observation of the Gamma-Ray Binary Candidate HESS J1832–093

    DEFF Research Database (Denmark)

    Mori, Kaya; Gotthelf, E. V.; Hailey, Charles J.

    2017-01-01

    −093, is detected up to ~30 keV and is well-described by an absorbed power-law model with a best-fit photon index . A re-analysis of archival Chandra and XMM-Newton data finds that the long-term X-ray flux increase of XMMU J183245−0921539 is (90% C.L.), much less than previously reported. A search for a pulsar spin...... of XMMU J183245−0921539 are most consistent with a non-accreting binary generating synchrotron X-rays from particle acceleration in the shock formed as a result of the pulsar and stellar wind collision. We also report on three nearby hard X-ray sources, one of which may be associated with diffuse emission...

  10. The Chandra Source Catalog : Automated Source Correlation

    Science.gov (United States)

    Hain, Roger; Evans, I. N.; Evans, J. D.; Glotfelty, K. J.; Anderson, C. S.; Bonaventura, N. R.; Chen, J. C.; Davis, J. E.; Doe, S. M.; Fabbiano, G.; Galle, E.; Gibbs, D. G.; Grier, J. D.; Hall, D. M.; Harbo, P. N.; He, X.; Houck, J. C.; Karovska, M.; Lauer, J.; McCollough, M. L.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Nowak, M. A.; Plummer, D. A.; Primini, F. A.; Refsdal, B. L.; Rots, A. H.; Siemiginowska, A. L.; Sundheim, B. A.; Tibbetts, M. S.; Van Stone, D. W.; Winkelman, S. L.; Zografou, P.

    2009-01-01

    Chandra Source Catalog (CSC) master source pipeline processing seeks to automatically detect sources and compute their properties. Since Chandra is a pointed mission and not a sky survey, different sky regions are observed for a different number of times at varying orientations, resolutions, and other heterogeneous conditions. While this provides an opportunity to collect data from a potentially large number of observing passes, it also creates challenges in determining the best way to combine different detection results for the most accurate characterization of the detected sources. The CSC master source pipeline correlates data from multiple observations by updating existing cataloged source information with new data from the same sky region as they become available. This process sometimes leads to relatively straightforward conclusions, such as when single sources from two observations are similar in size and position. Other observation results require more logic to combine, such as one observation finding a single, large source and another identifying multiple, smaller sources at the same position. We present examples of different overlapping source detections processed in the current version of the CSC master source pipeline. We explain how they are resolved into entries in the master source database, and examine the challenges of computing source properties for the same source detected multiple times. Future enhancements are also discussed. This work is supported by NASA contract NAS8-03060 (CXC).

  11. Synchrotron radiation sources and condensers for projection x-ray lithography

    International Nuclear Information System (INIS)

    Murphy, J.B.; MacDowell, A.A.; White, D.L.; Wood, O.R. II

    1992-01-01

    The design requirements for a compact electron storage ring that could be used as a soft x-ray source for projection lithography are discussed. The design concepts of the x-ray optics that are required to collect and condition the radiation in divergence, uniformity and direction to properly illuminate the mask and the particular x-ray projection camera used are discussed. Preliminary designs for an entire soft x-ray projection lithography system using an electron storage ring as a soft X-ray source are presented. It is shown that by combining the existing technology of storage rings with large collection angle condensers, a powerful and reliable source of 130 Angstrom photons for production line projection x-ray lithography is possible

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

    Science.gov (United States)

    2000-06-01

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

  13. Development of X-ray photoelectron microscope with a compact X-ray source generated by line-focused laser irradiation

    International Nuclear Information System (INIS)

    Yamaguchi, N.; Takahashi, Z.; Nishimura, Y.; Watanabe, K.; Okamoto, Y.; Sakata, A.; Azuma, H.; Hara, T.

    2005-01-01

    A laboratory-sized X-ray photoelectron microscope was constructed using a compact X-ray source produced by line-focused laser irradiation. The system is a scanning type photoelectron microscope where X-ray beam is micro-focused via Schwarzschild optics. A compact laser-plasma X-ray source has been developed with a YAG laser, a line-focus lens assembly, an Al tape-target driver and a debris prevention system. The 13.1 nm X-ray was delivered along line plasma whose length was 0.6 or 11 mm with higher intensity than that from a point-focused source. The Schwarzschild optics having the designed demagnification of 224, which was coated with Mo/Si multilayers for 13.1 nm X-ray, was set on the beamline 1 m distant from the source. The electron energy analyser was a spherical capacitor analyser with the photoelectron image detection system that was suited for detection of vast photoelectrons excited by an X-ray pulse of ns-order duration. The spatial resolution less than 5 μm has been confirmed from the variation of As 3d electron intensity along the position of the GaAs sample coated with a photo-resist test pattern

  14. INNOVATIONS IN THE ANALYSIS OF CHANDRA-ACIS OBSERVATIONS

    International Nuclear Information System (INIS)

    Broos, Patrick S.; Townsley, Leisa K.; Feigelson, Eric D.; Getman, Konstantin V.; Garmire, Gordon P.; Bauer, Franz E.

    2010-01-01

    As members of the instrument team for the Advanced CCD Imaging Spectrometer (ACIS) on NASA's Chandra X-ray Observatory and as Chandra General Observers, we have developed a wide variety of data analysis methods that we believe are useful to the Chandra community, and have constructed a significant body of publicly available software (the ACIS Extract package) addressing important ACIS data and science analysis tasks. This paper seeks to describe these data analysis methods for two purposes: to document the data analysis work performed in our own science projects and to help other ACIS observers judge whether these methods may be useful in their own projects (regardless of what tools and procedures they choose to implement those methods). The ACIS data analysis recommendations we offer here address much of the workflow in a typical ACIS project, including data preparation, point source detection via both wavelet decomposition and image reconstruction, masking point sources, identification of diffuse structures, event extraction for both point and diffuse sources, merging extractions from multiple observations, nonparametric broadband photometry, analysis of low-count spectra, and automation of these tasks. Many of the innovations presented here arise from several, often interwoven, complications that are found in many Chandra projects: large numbers of point sources (hundreds to several thousand), faint point sources, misaligned multiple observations of an astronomical field, point source crowding, and scientifically relevant diffuse emission.

  15. A multiwavelength study of SXP 1062, the long-period X-ray pulsar associated with a supernova remnant

    Science.gov (United States)

    González-Galán, A.; Oskinova, L. M.; Popov, S. B.; Haberl, F.; Kühnel, M.; Gallagher, J.; Schurch, M. P. E.; Guerrero, M. A.

    2018-04-01

    SXP 1062 is a Be X-ray binary (BeXB) located in the Small Magellanic Cloud. It hosts a long-period X-ray pulsar and is likely associated with the supernova remnant MCSNR J0127-7332. In this work we present a multiwavelength view on SXP 1062 in different luminosity regimes. We consider monitoring campaigns in optical (OGLE survey) and X-ray (Swift telescope). During these campaigns a tight coincidence of X-ray and optical outbursts is observed. We interpret this as typical Type I outbursts as often detected in BeXBs at periastron passage of the neutron star (NS). To study different X-ray luminosity regimes in depth, during the source quiescence we observed it with XMM-Newton while Chandra observations followed an X-ray outburst. Nearly simultaneously with Chandra observations in X-rays, in optical the RSS/SALT telescope obtained spectra of SXP 1062. On the basis of our multiwavelength campaign we propose a simple scenario where the disc of the Be star is observed face-on, while the orbit of the NS is inclined with respect to the disc. According to the model of quasi-spherical settling accretion our estimation of the magnetic field of the pulsar in SXP 1062 does not require an extremely strong magnetic field at the present time.

  16. 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

  17. X-ray Optics for BES Light Source Facilities

    International Nuclear Information System (INIS)

    Mills, Dennis; Padmore, Howard; Lessner, Eliane

    2013-01-01

    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

  18. Advanced imaging technology using carbon nanotube x ray source

    International Nuclear Information System (INIS)

    Choi, Hae Young; Seol, Seung Kown; Kim, Jaehoon; Yoo, Seung Hoon; Kim, Jong Uk

    2008-01-01

    Recently, X ray imaging technology is a useful and leading medical diagnostic tool for healthcare professionals to diagnose disease in human body. CNTs(i.e. carbon nanotubes)are used in many applications like FED, Micro wave amplifier, X ray source, etc. because of its suitable electrical, chemical and physical properties. Specially, CNTs are well used electron emitters for x ray source. Conventionally, thermionic type of tungsten filament x ray tube is widely employed in the field of bio medical and industrial application fields. However, intrinsic problems such as, poor emission efficiency and low imaging resolution cause the limitation of use of the x ray tube. To fulfill the current market requirement specifically for medical diagnostic field, we have developed rather a portable and compact CNT based x ray source in which high imaging resolution is provided. Electron sources used in X ray tubes should be well focused to the anode target for generation of high quality x ray. In this study, Pierce type x ray generation module was tested based its simulation results using by OPERA 3D code. Pierce type module is composed of cone type electrical lens with its number of them and inner angles of them that shows different results with these parameters. And some preliminary images obtained using the CNT x ray source were obtained. The represented images are the finger bone and teeth in human body. It is clear that the trabeculation shape is observed in finger bone. To obtain the finger bone image, tube currents of 250A at 42kV tube voltage was applied. The human tooth image, however, is somewhat unclear because the supplied voltage to the tube was limited to max. 50kV in the system developed. It should be noted that normally 60∼70kV of tube voltage is supplied in dental imaging. Considering these it should be emphasized that if the tube voltage is over 60kV then clearer image is possible. In this paper, we are discussed comparing between these experiment results and

  19. TRACING THE LOWEST PROPELLER LINE IN MAGELLANIC HIGH-MASS X-RAY BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Christodoulou, Dimitris M.; Laycock, Silas G. T.; Yang, Jun; Fingerman, Samuel, E-mail: dimitris_christodoulou@uml.edu, E-mail: silas_laycock@uml.edu, E-mail: jun_yang@uml.edu, E-mail: fingerman.samuel@gmail.com [Lowell Center for Space Science and Technology, 600 Suffolk Street, Lowell, MA 01854 (United States)

    2016-09-20

    We have combined the published observations of high-mass X-ray binary (HMXB) pulsars in the Magellanic Clouds with a new processing of the complete archival data sets from the XMM-Newton and Chandra observatories in an attempt to trace the lowest propeller line below which accretion to polar caps is inhibited by the centrifugal force and the pulsations from the most weakly magnetized pulsars cease. Previously published data reveal that some of the faster-spinning pulsars with spin periods of P {sub S} < 12 s, detected at relatively low X-ray luminosities L {sub X} , appear to define such a line in the P {sub S} – L {sub X} diagram, characterized by a magnetic moment of μ = 3 × 10{sup 29} G cm{sup 3}. This value implies the presence of surface magnetic fields of B ≥ 3 × 10{sup 11} G in the compact objects of this class. Only a few quiescent HMXBs are found below the propeller line: LXP4.40 and SXP4.78, for which XMM-Newton and Chandra null detections respectively placed firm upper limits on their X-ray fluxes in deep quiescence; and A0538-66, for which many sub-Eddington detections have never measured any pulsations. On the other hand, the data from the XMM-Newton and Chandra archives show clearly that, during routine observation cycles, several sources have been detected below the propeller line in extremely faint, nonpulsating states that can be understood as the result of weak magnetospheric emission when accretion to the poles is centrifugally stalled or severely diminished. We also pay attention to the anomalous X-ray pulsar CXOU J010043.1-721134 that was reported in HMXB surveys. Its pulsations and locations near and above the propeller line indicate that this pulsar could be accreting from a fossil disk.

  20. Chandra Discovers Cosmic Cannonball

    Science.gov (United States)

    2007-11-01

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

  1. On the origin of highly ionized X-ray absorbers detected in the galactic X-ray binaries

    International Nuclear Information System (INIS)

    Luo, Yang; Fang, Taotao

    2014-01-01

    X-ray observations of the Galactic X-ray binaries (XRBs) revealed numerous highly ionized metal absorption lines. However, it is unclear whether such lines are produced by the hot interstellar medium (ISM) or the circumstellar medium intrinsic to the binaries. Here we present a Chandra X-ray absorption line study of 28 observations of 12 XRBs, with a focus on the Ne IX and Fe XVII lines. We report the first detections of these lines in a significant amount of observations. We do not find a significant dependence of the line equivalent width on the distance of the XRBs, but we do see a weak dependence on the source X-ray luminosity. We also find 2 out of 12 selected targets show strong temporal variation of the Ne IX absorbers. While the line ratio between the two ion species suggests a temperature consistent with the previous predictions of the ISM, comparing with two theoretical models of the ISM shows the observed column densities are significantly higher than predictions. On the other hand, photoionization by the XRBs provides a reasonably good fit to the data. Our findings suggest that a significant fraction of these X-ray absorbers may originate in the hot gas intrinsic to the XRBs, and that the ISM makes small, if not negligible, contribution. We briefly discuss the implications to the study of the Milky Way hot gas content.

  2. ON THE X-RAY BALDWIN EFFECT IN ACTIVE GALACTIC NUCLEI OBSERVED BY THE CHANDRA HIGH-ENERGY GRATING

    International Nuclear Information System (INIS)

    Shu, X. W.; Wang, J. X.; Jiang, P.; Zhou, Y. Y.; Yaqoob, T.

    2012-01-01

    Using Chandra high-energy grating (HEG) observations of 32 active galactic nuclei (AGNs), we present a systematic study of the X-ray Baldwin effect (XBE; i.e., the anti-correlation between the narrow Fe Kα line equivalent width (EW) and X-ray continuum luminosity for AGN samples) with the highest spectral resolution currently available. We have previously reported an anti-correlation with EW∝L –0.22 2-10keV in an HEG sample, and the correlation is much weaker after averaging multiple observations of individual AGNs (EW∝L –0.13 2-10keV ). This indicates that rapid variation in the X-ray continuum plays an important role in producing the XBE, and such an effect should also be visible in individual AGNs. In this Letter, by normalizing the line EWs and continuum luminosities to the time-averaged values for each AGN in our sample with multiple HEG observations, we find a strong anti-correlation between EW and L X (EW/(EW)∝(L/(L)) –0.82±0.10 ), consistent with the XBE expected in an individual AGN if the narrow line flux remains constant while the continuum varies. This is first observational evidence that the Fe Kα line flux in a large sample of AGNs lacks a corresponding response to the continuum variation, supporting the fact that the narrow Fe-K line emission originates from a region far from the nucleus. We then performed Monte Carlo simulations to address whether the global XBE can be produced by X-ray continuum variation solely, and found that such an interpretation of the XBE cannot be ruled out statistically. One should thus be very cautious before drawing any scientific conclusion based on an observed XBE.

  3. Chandra High Resolution Imaging of NGC 1365 and NGC 4151

    Science.gov (United States)

    Wang, Junfeng; Fabbiano, G.; Elvis, M.; Risaliti, G.; Karovska, M.; Zezas, A.; Mazzarella, J. M.; Lord, S.; Howell, J. H.; Mundell, C. G.

    2010-07-01

    We present Chandra high resolution imaging of the circumnuclear regions of two nearby active galaxies, namely the starburst/AGN composite Seyfert 1.8 NGC 1365 and the archetypal Seyfert 1 NGC 4151. In NGC 1365, the X-ray morphology shows a biconical soft X-ray-emission region extending ~5 kpc in projection from the nucleus, coincident with the optical high-excitation outflows. Chandra HRC imaging of the NGC 4151 nucleus resolves X-ray emission from the 4 arcsec radio jet and the narrow line region (NLR) clouds. Our results demonstrate the unique power of spatially resolved spectroscopy with Chandra, and support previous claims that frequent jet-ISM interaction may explain why jets in Seyfert galaxies appear small, slow, and thermally dominated.

  4. High energy X-ray observations of COS-B gamma-ray sources from OSO-8

    Science.gov (United States)

    Dolan, J. F.; Crannell, C. J.; Dennis, B. R.; Frost, K. J.; Orwig, L. E.; Caraveo, P. A.

    1985-01-01

    During the three years between satellite launch in June 1975 and turn-off in October 1978, the high energy X-ray spectrometer on board OSO-8 observed nearly all of the COS-B gamma-ray source positions given in the 2CG catalog (Swanenburg et al., 1981). An X-ray source was detected at energies above 20 keV at the 6-sigma level of significance in the gamma-ray error box containing 2CG342 - 02 and at the 3-sigma level of significance in the error boxes containing 2CG065 + 00, 2CG195 + 04, and 2CG311 - 01. No definite association between the X-ray and gamma-ray sources can be made from these data alone. Upper limits are given for the 2CG sources from which no X-ray flux was detected above 20 keV.

  5. X-RAY AND RADIO OBSERVATIONS OF THE MASSIVE STAR-FORMING REGION IRAS 20126+4104

    Energy Technology Data Exchange (ETDEWEB)

    Montes, V. A.; Hofner, P.; Anderson, C.; Rosero, V. [Physics Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 (United States)

    2015-08-15

    We present results from Chandra ACIS-I and Karl G. Jansky Very Large Array 6 cm continuum observations of the IRAS 20126+4104 massive star-forming region. We detect 150 X-ray sources within the 17′ × 17′ ACIS-I field, and a total of 13 radio sources within the 9.′2 primary beam at 4.9 GHz. Among these observtions are the first 6 cm detections of the central sources reported by Hofner et al., namely, I20N1, I20S, and I20var. A new variable radio source is also reported. Searching the 2MASS archive, we identified 88 near-infrared (NIR) counterparts to the X-ray sources. Only four of the X-ray sources had 6 cm counterparts. Based on an NIR color–color analysis and on the Besançon simulation of Galactic stellar populations, we estimate that approximately 80 X-ray sources are associated with this massive star-forming region. We detect an increasing surface density of X-ray sources toward the massive protostar and infer the presence of a cluster of at least 43 young stellar objects within a distance of 1.2 pc from the massive protostar.

  6. Cosmological constraints from Chandra observations of galaxy clusters.

    Science.gov (United States)

    Allen, Steven W

    2002-09-15

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

  7. 21 CFR 872.1800 - Extraoral source x-ray system.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1800 Extraoral source x-ray system. (a... dental radiographic examination and diagnosis of diseases of the teeth, jaw, and oral structures. The x... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Extraoral source x-ray system. 872.1800 Section...

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

    Science.gov (United States)

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

    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.

  9. Laser-produced X-ray sources

    International Nuclear Information System (INIS)

    Hudson, L.T.; Seely, J.F.

    2010-01-01

    A formidable array of advanced laser systems are emerging that produce extreme states of light and matter. By irradiating solid and gaseous targets with lasers of increasing energy densities, new physical regimes of radiation effects are being explored for the first time in controlled laboratory settings. One result that is being accomplished or pursued using a variety of techniques, is the realization of novel sources of X-rays with unprecedented characteristics and light-matter interactions, the mechanisms of which are in many cases still being elucidated. Examples include the megajoule class of laser-produced plasmas designed in pursuit of alternative-energy and security applications and the petawatt class of lasers used for fast ignition and X-ray radiographic applications such as medical imaging and real-time imaging of plasma hydrodynamics. As these technologies mature, increased emphasis will need to be placed on advanced instrumentation and diagnostic metrology to characterize the spectra, time structure, and absolute brightness of X-rays emitted by these unconventional sources. Such customized and absolutely calibrated measurement tools will serve as an enabling technology that can help in assessing the overall system performance and progress, as well as identification of the underlying interaction mechanisms of interest to basic and applied strong-field and high-energy-density science.

  10. Compound refractive lenses for novel X-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Piestrup, M.A. E-mail: melpie@adelphitech.com; Beguiristain, H.R.; Gary, C.K.; Cremer, J.T.; Pantell, R.H.; Tatchyn, R

    2001-01-01

    We have measured the intensity profile of X-rays focused by a linear array of closely spaced spherical lenses fabricated using Mylar (C{sub 5}H{sub 4}O{sub 2}). We have experimentally demonstrated that we can achieve two-dimensional focusing for photon energies between 7 and 9 keV with imaging distances of less than 1 m. For example, using 8-keV X-rays we have achieved full-width-at-half-maximum (FWHM) linewidths down to 27.5 {mu}m at a distance of only 62 cm from the lens. The effective aperture of the lens was measured to be about 390 {mu}m with 38% transmission at 9 keV. A synchrotron source having source-size dimensions of 0.44x1.7 mm{sup 2} was utilized for the experimental work. Such lenses are seen as useful for focusing and increasing the intensity of novel X-ray sources that are directional and have small source size ({sigma}<1 mm)

  11. Miniaturized High-Speed Modulated X-Ray Source

    Science.gov (United States)

    Gendreau, Keith C. (Inventor); Arzoumanian, Zaven (Inventor); Kenyon, Steven J. (Inventor); Spartana, Nick Salvatore (Inventor)

    2015-01-01

    A miniaturized high-speed modulated X-ray source (MXS) device and a method for rapidly and arbitrarily varying with time the output X-ray photon intensities and energies. The MXS device includes an ultraviolet emitter that emits ultraviolet light, a photocathode operably coupled to the ultraviolet light-emitting diode that emits electrons, an electron multiplier operably coupled to the photocathode that multiplies incident electrons, and an anode operably coupled to the electron multiplier that is configured to produce X-rays. The method for modulating MXS includes modulating an intensity of an ultraviolet emitter to emit ultraviolet light, generating electrons in response to the ultraviolet light, multiplying the electrons to become more electrons, and producing X-rays by an anode that includes a target material configured to produce X-rays in response to impact of the more electrons.

  12. Table-top laser-driven ultrashort electron and X-ray source: the CIBER-X source project

    Energy Technology Data Exchange (ETDEWEB)

    Girardeau-Montaut, J.-P. E-mail: jean-pierre.girardeau@univ-lyonl.fr; Kiraly, Bela; Girardeau-Montaut, Claire; Leboutet, Hubert

    2000-09-21

    We report on the development of a new laser-driven table-top ultrashort electron and X-ray source, also called the CIBER-X source . X-ray pulses are produced by a three-step process which consists of the photoelectron emission from a thin metallic photocathode illuminated by 16 ps duration laser pulses at 213 nm. The e-gun is a standard Pierce diode electrode type, in which electrons are accelerated by a cw electric field of {approx}11 MV/m up to a hole made in the anode. The photoinjector produces a train of 70-80 keV electron pulses of {approx}0.5 nC and 20 A peak current at a repetition rate of 10 Hz. The electrons are then transported outside the diode along a path of 20 cm length, and are focused onto a target of thulium by magnetic fields produced by two electromagnetic coils. X-rays are then produced by the impact of electrons on the target. Simulations of geometrical, electromagnetic fields and energetic characteristics of the complete source were performed previously with the assistance of the code PIXEL1 also developed at the laboratory. Finally, experimental electron and X-ray performances of the CIBER-X source as well as its application to very low dose imagery are presented and discussed.

  13. The Frequency of Intrinsic X-Ray Weakness among Broad Absorption Line Quasars

    Science.gov (United States)

    Liu, Hezhen; Luo, B.; Brandt, W. N.; Gallagher, S. C.; Garmire, G. P.

    2018-06-01

    We present combined ≈14–37 ks Chandra observations of seven z = 1.6–2.7 broad absorption line (BAL) quasars selected from the Large Bright Quasar Survey (LBQS). These seven objects are high-ionization BAL (HiBAL) quasars, and they were undetected in the Chandra hard band (2–8 keV) in previous observations. The stacking analyses of previous Chandra observations suggested that these seven objects likely contain some candidates for intrinsically X-ray weak BAL quasars. With the new Chandra observations, six targets are detected. We calculate their effective power-law photon indices and hard-band flux weakness, and find that two objects, LBQS 1203+1530 and LBQS 1442–0011, show soft/steep spectral shapes ({{{Γ }}}eff}={2.2}-0.9+0.9 and {1.9}-0.8+0.9) and significant X-ray weakness in the hard band (by factors of ≈15 and 12). We conclude that the two HiBAL quasars are good candidates for intrinsically X-ray weak BAL quasars. The mid-infrared-to-ultraviolet spectral energy distributions of the two candidates are consistent with those of typical quasars. We constrain the fraction of intrinsically X-ray weak active galactic nuclei (AGNs) among HiBAL quasars to be ≈7%–10% (2/29–3/29), and we estimate it is ≈6%–23% (2/35–8/35) among the general BAL quasar population. Such a fraction is considerably larger than that among non-BAL quasars, and we suggest that intrinsically X-ray weak quasars are preferentially observed as BAL quasars. Intrinsically X-ray weak AGNs likely comprise a small minority of the luminous type 1 AGN population, and they should not affect significantly the completeness of these AGNs found in deep X-ray surveys.

  14. Galactic distribution of X-ray burst sources

    International Nuclear Information System (INIS)

    Lewin, W.H.G.; Hoffman, J.A.; Doty, J.; Clark, G.W.; Swank, J.H.; Becker, R.H.; Pravdo, S.H.; Serlemitsos, P.J.

    1977-01-01

    It is stated that 18 X-ray burst sources have been observed to date, applying the following definition for these bursts - rise times of less than a few seconds, durations of seconds to minutes, and recurrence in some regular pattern. If single burst events that meet the criteria of rise time and duration, but not recurrence are included, an additional seven sources can be added. A sky map is shown indicating their positions. The sources are spread along the galactic equator and cluster near low galactic longitudes, and their distribution is different from that of the observed globular clusters. Observations based on the SAS-3 X-ray observatory studies and the Goddard X-ray Spectroscopy Experiment on OSO-9 are described. The distribution of the sources is examined and the effect of uneven sky exposure on the observed distribution is evaluated. It has been suggested that the bursts are perhaps produced by remnants of disrupted globular clusters and specifically supermassive black holes. This would imply the existence of a new class of unknown objects, and at present is merely an ad hoc method of relating the burst sources to globular clusters. (U.K.)

  15. Chandra Looks Over a Cosmic Four-Leaf Clover

    Science.gov (United States)

    2004-07-01

    A careful analysis of observations by NASA's Chandra X-ray Observatory of a rare quadruple quasar has uncovered evidence that possibly a single star in a foreground galaxy magnified X-rays coming from the quasar. This discovery gives astronomers a new and extremely precise probe of the gas flow around the supermassive black hole that powers the quasar. "If our interpretation is correct, then we are seeing details around this black hole that are 50,000 times smaller than either the Hubble Space Telescope or Chandra could see under ordinary circumstances," said George Chartas of Penn State University in University Park, and lead author of a recent article on the Cloverleaf quasar in The Astrophysical Journal. The Cloverleaf quasar is a single object about 11 billion light years from Earth that appears as four images produced by a process known as gravitational lensing. If one or more galaxies lie along the line of sight to a more distant quasar, the gravitational field of the intervening galaxies can bend and magnify the light from the quasar and produce multiple images of it. The four images of the Cloverleaf quasar have been produced by one or more intervening galaxies. Cloverleaf Quasar Chandra X-ray Image of the Cloverleaf quasar One of the images (A), in the Cloverleaf is brighter than the others in both optical and X-ray light. Chartas and his colleagues found the relative brightness of this image was greater in X-ray than in optical light. The X-rays from iron atoms were also enhanced relative to X-rays at lower energies. Since the amount of brightening due to gravitational lensing does not vary with the wavelength, this means that an additional object has magnified the X-rays. The increased magnification of the X-ray light can be explained by gravitational microlensing, an effect which has been used to search for compact stars and planets in our galaxy. Microlensing occurs when a star or a multiple star system passes in front of light from a background object

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

    Science.gov (United States)

    2006-10-01

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

  17. Polarization and long-term variability of Sgr A* X-ray echo

    Science.gov (United States)

    Churazov, E.; Khabibullin, I.; Ponti, G.; Sunyaev, R.

    2017-06-01

    We use a model of the molecular gas distribution within ˜100 pc from the centre of the Milky Way (Kruijssen, Dale & Longmore) to simulate time evolution and polarization properties of the reflected X-ray emission, associated with the past outbursts from Sgr A*. While this model is too simple to describe the complexity of the true gas distribution, it illustrates the importance and power of long-term observations of the reflected emission. We show that the variable part of X-ray emission observed by Chandra and XMM-Newton from prominent molecular clouds is well described by a pure reflection model, providing strong support of the reflection scenario. While the identification of Sgr A* as a primary source for this reflected emission is already a very appealing hypothesis, a decisive test of this model can be provided by future X-ray polarimetric observations, which will allow placing constraints on the location of the primary source. In addition, X-ray polarimeters (like, e.g. XIPE) have sufficient sensitivity to constrain the line-of-sight positions of molecular complexes, removing major uncertainty in the model.

  18. Chandra Adds to Story of the Way We Were

    Science.gov (United States)

    2003-05-01

    Data from NASA's Chandra X-ray Observatory have enabled astronomers to use a new way to determine if a young star is surrounded by a planet-forming disk like our early Sun. These results suggest that disks around young stars can evolve rapidly to form planets, or they can be disrupted by close encounters with other stars. Chandra observed two young star systems, TW Hydrae and HD 98800, both of which are in the TW Hydrae Association, a loose cluster of 10 million-year-old stars. Observations at infrared and other wavelengths have shown that several stars in the TW Hydrae Association are surrounded by disks of dust and gas. At a distance of about 180 light years from Earth, these systems are among the nearest analogs to the early solar nebula from which Earth formed. "X-rays give us an excellent new way to probe the disks around stars," said Joel Kastner of the Rochester Institute of Technology in Rochester, NY during a press conference today in Nashville, Tenn. at a meeting of the American Astronomical Society. "They can tell us whether a disk is very near to its parent star and dumping matter onto it, or whether such activity has ceased to be important. In the latter case, presumably the disk has been assimilated into larger bodies - perhaps planets--or disrupted." TW Hydrae and HD 98800A Chandra 0th Order Image of HD98800 Kastner and his colleagues found examples of each type of behavior in their study. One star, TW Hydrae, namesake of the TW Hydrae Association, exhibited features in its X-ray spectrum that provide strong, new evidence that matter is accreting onto the star from a circumstellar disk. They concluded that matter is guided by the star's magnetic field onto one or more hot spots on the surface of the star. In contrast, Chandra observations of the young multiple star system HD 98800 revealed that its brightest star, HD 98800A, is producing X-rays much as the Sun does, from a hot upper atmosphere or corona. HD 98800 is a complex multiple-star system

  19. 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.

  20. X-ray source array

    International Nuclear Information System (INIS)

    Cooperstein, G.; Lanza, R.C.; Sohval, A.R.

    1983-01-01

    A circular array of cold cathode diode X-ray sources, for radiation imaging applications, such as computed tomography includes electrically conductive cathode plates each of which cooperates with at least two anodes to form at least two diode sources. In one arrangement, two annular cathodes are separated by radially extending, rod-like anodes. Field enhancement blades may be provided on the cathodes. In an alternative arrangement, the cathode plates extend radially and each pair is separated by an anode plate also extending radially. (author)

  1. A Full Year's Chandra Exposure on Sloan Digital Sky Survey Quasars from the Chandra Multiwavelength Project

    Science.gov (United States)

    Green, Paul J.; Aldcroft, T. L.; Richards, G. T.; Barkhouse, W. A.; Constantin, A.; Haggard, D.; Karovska, M.; Kim, D.-W.; Kim, M.; Vikhlinin, A.; Anderson, S. F.; Mossman, A.; Kashyap, V.; Myers, A. D.; Silverman, J. D.; Wilkes, B. J.; Tananbaum, H.

    2009-01-01

    We study the spectral energy distributions and evolution of a large sample of optically selected quasars from the Sloan Digital Sky Survey that were observed in 323 Chandra images analyzed by the Chandra Multiwavelength Project. Our highest-confidence matched sample includes 1135 X-ray detected quasars in the redshift range 0.2 3, substantially expanding the known sample. We find no evidence for evolution out to z ~ 5 for either the X-ray photon index Γ or for the ratio of optical/UV to X-ray flux αox. About 10% of detected QSOs show best-fit intrinsic absorbing columns greater than 1022 cm-2, but the fraction might reach ~1/3 if most nondetections are absorbed. We confirm a significant correlation between αox and optical luminosity, but it flattens or disappears for fainter (MB gsim -23) active galactic nucleus (AGN) alone. We report significant hardening of Γ both toward higher X-ray luminosity, and for relatively X-ray loud quasars. These trends may represent a relative increase in nonthermal X-ray emission, and our findings thereby strengthen analogies between Galactic black hole binaries and AGN. For uniformly selected subsamples of narrow-line Seyfert 1s and narrow absorption line QSOs, we find no evidence for unusual distributions of either αox or Γ.

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

    International Nuclear Information System (INIS)

    Nicoul, Matthieu

    2010-01-01

    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 γ e / γ 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 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 and its development for excitations close to the

  3. 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

  4. The Geometry of the Infrared and X-Ray Obscurer in a Dusty Hyperluminous Quasar

    DEFF Research Database (Denmark)

    Farrah, Duncan; Baloković, Mislav; Stern, Daniel

    2016-01-01

    We study the geometry of the active galactic nucleus (AGN) obscurer in IRAS 09104+4109, an IR-luminous, radio-intermediate FR-I source at z = 0.442, using infrared data from Spitzer and Herschel, X-ray data from NuSTAR, Swift, Suzaku, and Chandra, and an optical spectrum from Palomar. The infrare...

  5. Simulation of a dense plasma focus x-ray source

    International Nuclear Information System (INIS)

    Stark, R.A.

    1994-01-01

    The authors are performing simulations of the magnetohydrodynamics of a Dense Plasma Focus (DPF) x-ray source located at Science Research Laboratory (SRL), Alameda, CA, in order to optimize its performance. The SRL DPF, which was developed as a compact source for x-ray lithography, operates at 20 Hz, giving x-ray power (9--14 Angstroms) of 500 W using neon gas. The simulations are performed with the two dimensional MHD code MACH2, developed by Mission Research Corporation, with a steady state corona model as the equation of state. The results of studies of the sensitivity of x-ray output to charging voltage and current, and to initial gas density will be presented. These studies should indicate ways to optimize x-ray production efficiency. Simulations of various inner electrode configurations will also be presented

  6. Parameters estimation for X-ray sources: positions

    International Nuclear Information System (INIS)

    Avni, Y.

    1977-01-01

    It is shown that the sizes of the positional error boxes for x-ray sources can be determined by using an estimation method which we have previously formulated generally and applied in spectral analyses. It is explained how this method can be used by scanning x-ray telescopes, by rotating modulation collimators, and by HEAO-A (author)

  7. Scientists Find X Rays from Stellar Winds That May Play Significant Role in Galactic Evolution

    Science.gov (United States)

    2001-09-01

    Colorful star-forming regions that have captivated stargazers since the advent of the telescope 400 years ago contain gas thousands of times more energetic than previously recognized, powered by colliding stellar winds. This multimillion-degree gas radiated as X rays is one of the long-sought sources of energy and elements in the Milky Way galaxy's interstellar medium. A team led by Leisa Townsley, a senior research associate in astronomy and astrophysics at Penn State University, uncovered this wind phenomenon in the Rosette Nebula, a stellar nursery. With the Chandra X-ray Observatory, the team found that the most massive stars in the nebula produce winds that slam into each other, create violent shocks, and infuse the region with 6-million-degree gas. The findings are presented in Washington, D.C., today at a conference entitled "Two Years of Science with Chandra." "A ghostly glow of diffuse X-ray emission pervades the Rosette Nebula and perhaps many other similar star-forming regions throughout the Galaxy," said Townsley. "We now have a new view of the engine lighting the beautiful Rosette Nebula and new evidence for how the interstellar medium may be energized." Townsley and her colleagues created a striking X-ray panorama of the Rosette Molecular Cloud from four images with Chandra's Advanced CCD Imaging Spectrometer. This is a swath of the sky nearly 100 light years across sprayed with hundreds of X-ray-emitting young stars. In one corner of the Rosette Molecular Cloud lies the Rosette Nebula, called an "H II region" because the hydrogen gas there has been stripped of its electrons due to the strong ultraviolet radiation from its young stars. This region, about 5,000 light years away in the constellation Monoceros, the Unicorn, has long been a favorite among amateur astronomers. The wispy, colorful display is visible with small telescopes. The Chandra survey reveals, for the first time, 6-million-degree gas at the center of the Rosette Nebula, occupying a

  8. 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.

  9. Optical colours of AGN in the Extended Chandra Deep Field South: Obscured black holes in early type galaxies

    OpenAIRE

    Rovilos, E.; Georgantopoulos, I.

    2007-01-01

    We investigate the optical colours of X-ray sources from the Extended Chandra Deep Field South (ECDFS) using photometry from the COMBO-17 survey, aiming to explore AGN - galaxy feedback models. The X-ray sources populate both the ``blue'' and the ``red sequence'' on the colour-magnitude diagram. However, sources in the ``red sequence'' appear systematically more obscured. HST imaging from the GEMS survey demonstrates that the nucleus does not affect significantly the observed colours, and the...

  10. The Elusive Soft Emission from Hard X-ray Symbiotic System RT Cru

    Science.gov (United States)

    Karovska, Margarita

    2014-09-01

    RT Cru is a fascinating member of a new class of hard X-ray emitting symbiotic binaries showing X-ray emission extending to over 50keV. While its hard X-ray emission has been studied in detail, the soft component of the spectrum, including flares, remains elusive, since previous observations have focused on the high-energy regime. We propose Chandra HRC-S/LETG observations to determine the spatial, spectral, and temporal characteristics of the source of the soft X-ray emission with a goal to establish the origin of the soft component, and determine whether and how it is tied to the hard component. Determining the origin of the soft emission is a crucial piece of the puzzle to understanding the geometry, energetics, and the environment of WD accretion in this class of symbiotic systems.

  11. 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.

  12. Studies of dark energy with X-ray observatories.

    Science.gov (United States)

    Vikhlinin, Alexey

    2010-04-20

    I review the contribution of Chandra X-ray Observatory to studies of dark energy. There are two broad classes of observable effects of dark energy: evolution of the expansion rate of the Universe, and slow down in the rate of growth of cosmic structures. Chandra has detected and measured both of these effects through observations of galaxy clusters. A combination of the Chandra results with other cosmological datasets leads to 5% constraints on the dark energy equation-of-state parameter, and limits possible deviations of gravity on large scales from general relativity.

  13. Exploratory X-ray monitoring of luminous radio-quiet quasars at high redshift: Initial results

    Energy Technology Data Exchange (ETDEWEB)

    Shemmer, Ohad; Stein, Matthew S. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Brandt, W. N.; Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Paolillo, Maurizio [Dipartimento di Scienze Fisiche, Università Federico II di Napoli, via Cinthia 6, I-80126 Napoli (Italy); Kaspi, Shai [School of Physics and Astronomy and the Wise Observatory, Tel Aviv University, Tel Aviv 69978 (Israel); Vignali, Cristian [Dipartimento di Astronomia, Università degli studi di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Lira, Paulina [Departamento de Astronomia, Universidad de Chile, Camino del Observatorio 1515, Santiago (Chile); Gibson, Robert R., E-mail: ohad@unt.edu [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)

    2014-03-10

    We present initial results from an exploratory X-ray monitoring project of two groups of comparably luminous radio-quiet quasars (RQQs). The first consists of four sources at 4.10 ≤ z ≤ 4.35, monitored by Chandra, and the second is a comparison sample of three sources at 1.33 ≤ z ≤ 2.74, monitored by Swift. Together with archival X-ray data, the total rest-frame temporal baseline spans ∼2-4 yr and ∼5-13 yr for the first and second group, respectively. Six of these sources show significant X-ray variability over rest-frame timescales of ∼10{sup 2}-10{sup 3} days; three of these also show significant X-ray variability on rest-frame timescales of ∼1-10 days. The X-ray variability properties of our variable sources are similar to those exhibited by nearby and far less luminous active galactic nuclei (AGNs). While we do not directly detect a trend of increasing X-ray variability with redshift, we do confirm previous reports of luminous AGNs exhibiting X-ray variability above that expected from their luminosities, based on simplistic extrapolation from lower luminosity sources. This result may be attributed to luminous sources at the highest redshifts having relatively high accretion rates. Complementary UV-optical monitoring of our sources shows that variations in their optical-X-ray spectral energy distribution are dominated by the X-ray variations. We confirm previous reports of X-ray spectral variations in one of our sources, HS 1700+6416, but do not detect such variations in any of our other sources in spite of X-ray flux variations of up to a factor of ∼4. This project is designed to provide a basic assessment of the X-ray variability properties of RQQs at the highest accessible redshifts that will serve as a benchmark for more systematic monitoring of such sources with future X-ray missions.

  14. Hard X-ray balloon observations of compact galactic and extragalactic X-ray sources

    International Nuclear Information System (INIS)

    Staubert, R.; Kendziorra, E.; Pietsch, W.; Proctor, R.J.; Reppin, C.; Steinle, H.; Truemper, J.; Voges, W.

    1981-01-01

    A balloon program in hard X-ray astronomy (20-200 keV) is jointly pursued by the Astronomisches Institut der Universitaet Tuebingen (AIT) and the Max Planck-Institut fuer Extraterrestrische Physik in Garching (MPE). Since 1973 nine succussful balloon flights have been performed from Texas and Australia. Here results on Centaurus A and on several galactic binary X-ray sources are summarized. In particular the high energy photon spectrum of Hercules X-1 and the evidence for the cyclotron line feature which was discovered by us in 1976 is reviewed. (orig.)

  15. The XMM deep survey in the CDF-S. X. X-ray variability of bright sources

    Science.gov (United States)

    Falocco, S.; Paolillo, M.; Comastri, A.; Carrera, F. J.; Ranalli, P.; Iwasawa, K.; Georgantopoulos, I.; Vignali, C.; Gilli, R.

    2017-12-01

    Aims: We aim to study the variability properties of bright hard X-ray selected active galactic nuclei (AGN) in the redshift range between 0.3 and 1.6 detected in the Chandra Deep Field South (XMM-CDFS) by a long ( 3 Ms) XMM observation. Methods: Taking advantage of the good count statistics in the XMM CDFS, we search for flux and spectral variability using the hardness ratio (HR) techniques. We also investigate the spectral variability of different spectral components (photon index of the power law, column density of the local absorber, and reflection intensity). The spectra were merged in six epochs (defined as adjacent observations) and in high and low flux states to understand whether the flux transitions are accompanied by spectral changes. Results: The flux variability is significant in all the sources investigated. The HRs in general are not as variable as the fluxes, in line with previous results on deep fields. Only one source displays a variable HR, anti-correlated with the flux (source 337). The spectral analysis in the available epochs confirms the steeper when brighter trend consistent with Comptonisation models only in this source at 99% confidence level. Finding this trend in one out of seven unabsorbed sources is consistent, within the statistical limits, with the 15% of unabsorbed AGN in previous deep surveys. No significant variability in the column densities, nor in the Compton reflection component, has been detected across the epochs considered. The high and low states display in general different normalisations but consistent spectral properties. Conclusions: X-ray flux fluctuations are ubiquitous in AGN, though in some cases the data quality does not allow for their detection. In general, the significant flux variations are not associated with spectral variability: photon index and column densities are not significantly variable in nine out of the ten AGN over long timescales (from three to six and a half years). Photon index variability is

  16. Optical technologies for extreme-ultraviolet and soft X-ray coherent sources

    International Nuclear Information System (INIS)

    Canova, Federico; 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 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.

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

    Science.gov (United States)

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

    2000-01-01

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

  18. A CHANDRA OBSERVATION OF SNR 0540 - 697

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  19. 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.

  20. Observation of extragalactic X-ray sources

    International Nuclear Information System (INIS)

    Bui-Van, Andre.

    1973-01-01

    A narrow angular resolution detection apparatus using a high performance collimator has proved particularly well suited for the programs of observation of X ray sources. The experimental set-up and its performance are described. One chapter deals with the particular problems involved in the observation of X ray sources with the aid of sounding balloons. The absorption of extraterrestrial photons by the earth atmosphere is taken into account in the procesing of the observation data using two methods of calculation: digital and with simulation techniques. The results of three balloon flights are then presented with the interpretation of the observations carried out using both thermal and non thermal emission models. This analysis leads to some possible characteristics of structure of the Perseus galaxy cluster [fr

  1. Super-Eddington accretion on to the neutron star NGC 7793 P13: Broad-band X-ray spectroscopy and ultraluminous X-ray sources

    Science.gov (United States)

    Walton, D. J.; Fürst, F.; Harrison, F. A.; Stern, D.; Bachetti, M.; Barret, D.; Brightman, M.; Fabian, A. C.; Middleton, M. J.; Ptak, A.; Tao, L.

    2018-02-01

    We present a detailed, broad-band X-ray spectral analysis of the ultraluminous X-ray source (ULX) pulsar NGC 7793 P13, a known super-Eddington source, utilizing data from the XMM-Newton, NuSTAR and Chandra observatories. The broad-band XMM-Newton+NuSTAR spectrum of P13 is qualitatively similar to the rest of the ULX sample with broad-band coverage, suggesting that additional ULXs in the known population may host neutron star accretors. Through time-averaged, phase-resolved and multi-epoch studies, we find that two non-pulsed thermal blackbody components with temperatures ∼0.5 and 1.5 keV are required to fit the data below 10 keV, in addition to a third continuum component which extends to higher energies and is associated with the pulsed emission from the accretion column. The characteristic radii of the thermal components appear to be comparable, and are too large to be associated with the neutron star itself, so the need for two components likely indicates the accretion flow outside the magnetosphere is complex. We suggest a scenario in which the thick inner disc expected for super-Eddington accretion begins to form, but is terminated by the neutron star's magnetic field soon after its onset, implying a limit of B ≲ 6 × 1012 G for the dipolar component of the central neutron star's magnetic field. Evidence of similar termination of the disc in other sources may offer a further means of identifying additional neutron star ULXs. Finally, we examine the spectrum exhibited by P13 during one of its unusual 'off' states. These data require both a hard power-law component, suggesting residual accretion on to the neutron star, and emission from a thermal plasma, which we argue is likely associated with the P13 system.

  2. Very Luminous X-ray Point Sources in Starburst Galaxies

    Science.gov (United States)

    Colbert, E.; Heckman, T.; Ptak, A.; Weaver, K. A.; Strickland, D.

    Extranuclear X-ray point sources in external galaxies with luminosities above 1039.0 erg/s are quite common in elliptical, disk and dwarf galaxies, with an average of ~ 0.5 and dwarf galaxies, with an average of ~0.5 sources per galaxy. These objects may be a new class of object, perhaps accreting intermediate-mass black holes, or beamed stellar mass black hole binaries. Starburst galaxies tend to have a larger number of these intermediate-luminosity X-ray objects (IXOs), as well as a large number of lower-luminosity (1037 - 1039 erg/s) point sources. These point sources dominate the total hard X-ray emission in starburst galaxies. We present a review of both types of objects and discuss possible schemes for their formation.

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

    Science.gov (United States)

    2002-10-01

    New evidence from NASA's Chandra X-ray Observatory challenges an alternative theory of gravity that eliminates the need for dark matter. The observation also narrows the field for competing forms of dark matter, the elusive material thought to be the dominant form of matter in the universe. An observation of the galaxy NGC 720 shows it is enveloped in a slightly flattened, or ellipsoidal cloud of hot gas that has an orientation different from that of the optical image of the galaxy. The flattening is too large to be explained by theories in which stars and gas are assumed to contain most of the mass in the galaxy. "The shape and orientation of the hot gas cloud require it to be confined by an egg-shaped dark matter halo," said David Buote of the University of California, Irvine, and lead author of a report on this research in the 2002 September 20 issue of The Astrophysical Journal. "This means that dark matter is not just an illusion due to a shortcoming of the standard theory of gravity - it is real." According to the generally accepted standard theory of gravity, the hot X-ray cloud would need an additional source of gravity - a halo of dark matter - to keep the hot gas from expanding away. The mass of dark matter required would be about five to ten times the mass of the stars in the galaxy. If the dark matter tracked the optical light from the stars in the galaxy, the hot X-ray cloud would be more round than it is. The flattened shape of the hot gas cloud requires a flattened dark matter halo. An alternative theory of gravity called MOND, for Modified Newtonian Dynamics, was proposed in 1983 by Mordecai Milgrom of the Weizmann Institute in Israel, and has remained viable over the years. MOND does away with the need for dark matter by modifying the theory where the acceleration produced by gravity is very small, such as the outskirts of galaxies. However, MOND cannot explain the Chandra observation of NGC 720. This is apparently the first dynamical evidence that

  4. 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

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

    International Nuclear Information System (INIS)

    Sisniega, A.; Vaquero, J. J.; Desco, M.

    2014-01-01

    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

  6. Linear polarization observations of some X-ray sources

    International Nuclear Information System (INIS)

    Shakhovskoy, N.M.; Efimov, Yu.S.

    1975-01-01

    Multicolour linear polarization of optical radiation of the X-ray sources Sco X-1, Cyg X-2, Cyg X-1 and Her X-1 was measured at the Crimean Astrophysical Observatory in 1970-1973. These observations indicate that polarization of Sco X-1 in the ultraviolet, blue and red spectral regions appears to be variable. No statistically significant variations of polarization were found for the other three sources observed. (Auth.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-15

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

  8. X-ray constraints on the number of stellar mass black holes in the inner parsec

    International Nuclear Information System (INIS)

    Deegan, Patrick; Nayakshin, Sergei

    2006-01-01

    Due to dynamical friction stellar mass black holes should form a cusp in the inner parsec. Calculations [5, 6] show that approximately 20 thousand black holes would be present in a sphere with radius of about a parsec around Sgr A*. The presence of these objects opens up the possibility that they might be accreting ''cool'' gas (i.e. the Minispiral) as discussed by Morris [6]. Here we calculate the X-ray emission expected from these black holes as a method to constrain their population. We find that the data limits the total number of such black holes to around 10 - 20 thousand. Even a much smaller number of such black holes, i.e. 5 thousand, is sufficient to produce several sources with X-ray luminosity above L x ∼ 10 33 erg s -1 at any one time. We suggest that some of the discrete X-ray sources observed by Muno [7] with Chandra in the inner parsec may be such ''fake X-ray binaries''

  9. Measuring the black hole mass in ultraluminous X-ray sources with the X-ray scaling method

    Science.gov (United States)

    Jang, I.; Gliozzi, M.; Satyapal, S.; Titarchuk, L.

    2018-01-01

    In our recent work, we demonstrated that a novel X-ray scaling method, originally introduced for Galactic black holes (BH), could be reliably extended to estimate the mass of supermassive black holes accreting at moderate to high level. Here, we apply this X-ray scaling method to ultraluminous X-ray sources (ULXs) to constrain their MBH. Using 49 ULXs with multiple XMM-Newton observations, we infer that ULXs host both stellar mass BHs and intermediate mass BHs. The majority of the sources of our sample seem to be consistent with the hypothesis of highly accreting massive stellar BHs with MBH ∼ 100 M⊙. Our results are in general agreement with the MBH values obtained with alternative methods, including model-independent variability methods. This suggests that the X-ray scaling method is an actual scale-independent method that can be applied to all BH systems accreting at moderate-high rate.

  10. A Chandra Observation of the Ultraluminous Infrared Galaxy IRAS 19254-7245 (The Superantennae): X-Ray Emission from the Compton-Thick Active Galactic Nucleus and the Diffuse Starburst

    Science.gov (United States)

    Jia, Jianjun; Ptak, Andrew; Heckman, Timothy M.; Braito, Valentina; Reeves, James

    2012-01-01

    We present a Chandra observation of IRAS 19254-7245, a nearby ultraluminous infrared galaxy also known as the Superantennae. The high spatial resolution of Chandra allows us to disentangle for the first time the diffuse starburst (SB) emission from the embedded Compton-thick active galactic nucleus (AGN) in the southern nucleus. No AGN activity is detected in the northern nucleus. The 2-10 keV spectrum of the AGN emission is fitted by a flat power law (TAU = 1.3) and an He-like Fe Kalpha line with equivalent width 1.5 keV, consistent with previous observations. The Fe K line profile could be resolved as a blend of a neutral 6.4 keV line and an ionized 6.7 keV (He-like) or 6.9 keV (H-like) line. Variability of the neutral line is detected compared with the previous XMM-Newton and Suzaku observations, demonstrating the compact size of the iron line emission. The spectrum of the galaxy-scale extended emission excluding the AGN and other bright point sources is fitted with a thermal component with a best-fit kT of approximately 0.8 keV. The 2-10 keV luminosity of the extended emission is about one order of magnitude lower than that of the AGN. The basic physical and structural properties of the extended emission are fully consistent with a galactic wind being driven by the SB. A candidate ultraluminous X-ray source is detected 8 south of the southern nucleus. The 0.3 - 10 keV luminosity of this off-nuclear point source is approximately 6 x 10(exp 40) erg per second if the emission is isotropic and the source is associated with the Superantennae.

  11. Total-reflection x-ray fluorescence with a brillant undulator x-ray source

    International Nuclear Information System (INIS)

    Sakurai, K.; Eba, H.; Numako, C.; Suzuki, M.; Inoue, K.; Yagi, N.

    2000-01-01

    Total-reflection x-ray fluorescence (TXRF) is a highly sensitive technique for analyzing trace elements, because of the very low background from the sample support. Use of third-generation synchrotron x-ray source could further enhance the detection power. However, while such high sensitivity permits the detection of signals from trace elements of interest, it also means that one can observe weak parasitic x-rays as well. If the sample surface becomes even slightly contaminated, owing to air particulates near the beamline, x-ray fluorescence lines of iron, zinc, copper, nickel, chromium, and titanium can be observed even for a blank sample. Another critical problem is the low-energy-side tail of the scattering x-rays, which ultimately restricts the detection capability of the technique using a TXRF spectrometer based on a Si(Li) detector. The present paper describes our experiments with brilliant undulator x-ray beams at BL39XU and BL40XU, at the SPring-8, Harima, Japan. The emphasis is on the development of instruments to analyze a droplet of 0.1 μl containing trace elements of ppb level. Although the beamline is not a clean room, we have employed equipment for preparing a clean sample and also for avoiding contamination during transferring the sample into the spectrometer. We will report on the successful detection of the peak from 0.8 ppb selenium in a droplet (absolute amount 80 fg). We will also present the results of recent experiments obtained from a Johansson spectrometer rather than a Si(Li) detector. (author)

  12. Spectral and Temporal Properties of the Ultra-Luminous X-Ray Pulsar in M82 from 15 Years of Chandra Observations and Analysis of the Pulsed Emission Using NuSTAR

    Science.gov (United States)

    Brightman, Murray; Harrison, Fiona; Walton, Dominic J.; Fuerst, Felis; Zezas, Andreas; Bachetti, Matteo; Grefenstette, Brian; Ptak, Andrew; Tendulkar, Shriharsh; Yukita, Mihoko

    2016-01-01

    The recent discovery by Bachetti et al. of a pulsar in M82 that can reach luminosities of up to 10(exp 40) erg s(exp -1), a factor of approximately 100 times the Eddington luminosity for a 1.4 solar mass compact object, poses a challenge for accretion physics. In order to better understand the nature of this source and its duty cycle, and in light of several physical models that have been subsequently published, we conduct a spectral and temporal analysis of the 0.58 keV X-ray emission from this source from 15 years of Chandra observations. We analyze 19 ACIS observations where the point-spread function (PSF) of the pulsar is not contaminated by nearby sources. We fit the Chandra spectra of the pulsar with a power-law model and a disk blackbody model, subjected to interstellar absorption in M82. We carefully assess for the effect of pile-up in our observations, where four observations have a pile-up fraction of 10, which we account for during spectral modeling with a convolution model. When fitted with a power-law model, the average photon index when the source is at high luminosity (LX greater than 10(exp 39) erg s(exp -1) is equal to gamma 1.33 +/-.0.15. For the disk blackbody model, the average temperature is T(sub in) 3.24 +/- 0.65 keV, the spectral shape being consistent with other luminous X-ray pulsars. We also investigated the inclusion of a soft excess component and spectral break, finding that the spectra are also consistent with these features common to luminous X-ray pulsars. In addition, we present spectral analysis from NuSTAR over the 3-50 keV range where we have isolated the pulsed component. We find that the pulsed emission in this band is best fit by a power-law with a high-energy cutoff, where gamma is equal to 0.6 +/- 0.3 and E(sub C) is equal to 14(exp +5) (sub -3)) keV. While the pulsar has previously been identified as a transient, we find from our longer-baseline study that it has been remarkably active over the 15-year period, where for 9

  13. The simulated spectrum of the OGRE X-ray EM-CCD camera system

    Science.gov (United States)

    Lewis, M.; Soman, M.; Holland, A.; Lumb, D.; Tutt, J.; McEntaffer, R.; Schultz, T.; Holland, K.

    2017-12-01

    The X-ray astronomical telescopes in use today, such as Chandra and XMM-Newton, use X-ray grating spectrometers to probe the high energy physics of the Universe. These instruments typically use reflective optics for focussing onto gratings that disperse incident X-rays across a detector, often a Charge-Coupled Device (CCD). The X-ray energy is determined from the position that it was detected on the CCD. Improved technology for the next generation of X-ray grating spectrometers has been developed and will be tested on a sounding rocket experiment known as the Off-plane Grating Rocket Experiment (OGRE). OGRE aims to capture the highest resolution soft X-ray spectrum of Capella, a well-known astronomical X-ray source, during an observation period lasting between 3 and 6 minutes whilst proving the performance and suitability of three key components. These three components consist of a telescope made from silicon mirrors, gold coated silicon X-ray diffraction gratings and a camera that comprises of four Electron-Multiplying (EM)-CCDs that will be arranged to observe the soft X-rays dispersed by the gratings. EM-CCDs have an architecture similar to standard CCDs, with the addition of an EM gain register where the electron signal is amplified so that the effective signal-to-noise ratio of the imager is improved. The devices also have incredibly favourable Quantum Efficiency values for detecting soft X-ray photons. On OGRE, this improved detector performance allows for easier identification of low energy X-rays and fast readouts due to the amplified signal charge making readout noise almost negligible. A simulation that applies the OGRE instrument performance to the Capella soft X-ray spectrum has been developed that allows the distribution of X-rays onto the EM-CCDs to be predicted. A proposed optical model is also discussed which would enable the missions minimum success criteria's photon count requirement to have a high chance of being met with the shortest possible

  14. 13.1 micrometers hard X-ray focusing by a new type monocapillary X-ray optic designed for common laboratory X-ray source

    Science.gov (United States)

    Sun, Xuepeng; zhang, Xiaoyun; Zhu, Yu; Wang, Yabing; Shang, Hongzhong; Zhang, Fengshou; Liu, Zhiguo; Sun, Tianxi

    2018-04-01

    A new type of monocapillary X-ray optic, called 'two bounces monocapillary X-ray optics' (TBMXO), is proposed for generating a small focal spot with high power-density gain for micro X-ray analysis, using a common laboratory X-ray source. TBMXO is consists of two parts: an ellipsoidal part and a tapered part. Before experimental testing, the TBMXO was simulated by the ray tracing method in MATLAB. The simulated results predicted that the proposed TBMXO would produce a smaller focal spot with higher power-density gain than the ellipsoidal monocapillary X-ray optic (EMXO). In the experiment, the TBMXO performance was tested by both an optical device and a Cu target X-ray tube with focal spot of 100 μm. The results indicated that the TBMXO had a slope error of 57.6 μrad and a 13.1 μm focal spot and a 1360 gain in power density were obtained.

  15. WORKSHOP: Accreting X-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-09-15

    Earlier this year a workshop on 'High Energy/Ultra High Energy Behaviour of Accreting X-Ray Sources' was held in Vulcano, a small island near Sicily, jointly organized by the Italian Istituto Nazionale di Fisica Nucleare and Consiglio Nazionale delle Ricerche. About 60 astrophysicists and particle physicists attended the meeting which covered the study of galactic cosmic sources emitting in the wide energy range from the optical region to some 10{sup 15} eV.

  16. Assembling x-ray sources by carbon nanotubes

    Science.gov (United States)

    Sessa, V.; Lucci, M.; Toschi, F.; Orlanducci, S.; Tamburri, E.; Terranova, M. L.; Ciorba, A.; Rossi, M.; Hampai, D.; Cappuccio, G.

    2007-05-01

    By the use of a chemical vapour deposition technique a series of metal wires (W, Ta, Steel ) with differently shaped tips have been coated by arrays of single wall carbon nanotubes (SWNT). The field emission properties of the SWNT deposits have been measured by a home made apparatus working in medium vacuum (10 -6- 10 -7 mbar) and the SWNT-coated wires have been used to fabricate tiny electron sources for X-ray tubes. To check the efficiency of the nanotube coated wires for X-ray generation has, a prototype X-ray tube has been designed and fabricated. The X-ray tube works at pressures about 10 -6 mbar. The target ( Al film) is disposed on a hole in the stainless steel sheath: this configuration makes unnecessary the usual Be window and moreover allows us to use low accelerating potentials (< 6 kV).

  17. Point X-ray sources in the SNR G 315.4-2.30 (MSH 14-63, RCW 86)

    Science.gov (United States)

    Gvaramadze, V. V.; Vikhlinin, A. A.

    2003-04-01

    We report the results of a search for a point X-ray source (stellar remnant) in the southwest protrusion of the supernova remnant G 315.4-2.30 (MSH 14-63, RCW 86) using the archival data of the Chandra X-ray Observatory. The search was motivated by a hypothesis that G 315.4-2.30 is the result of an off-centered cavity supernova explosion of a moving massive star, which ended its evolution just near the edge of the main-sequence wind-driven bubble. This hypothesis implies that the southwest protrusion in G 315.4-2.30 is the remainder of a pre-existing bow shock-like structure created by the interaction of the supernova progenitor's wind with the interstellar medium and that the actual location of the supernova blast center is near the center of this hemispherical structure. We have discovered two point X-ray sources in the ``proper" place. One of the sources has an optical counterpart with the photographic magnitude 13.38+/-0.40, while the spectrum of the source can be fitted with an optically thin plasma model. We interpret this source as a foreground active star of late spectral type. The second source has no optical counterpart to a limiting magnitude ~ 21. The spectrum of this source can be fitted almost equally well with several simple models (power law: photon index =1.87; two-temperature blackbody: kT1 =0.11 keV, R1 =2.34 km and kT2 =0.71 keV, R2 =0.06 km; blackbody plus power law: kT =0.07 keV, photon index =2.3). We interpret this source as a candidate stellar remnant (neutron star), while the photon index and non-thermal luminosity of the source (almost the same as those of the Vela pulsar and the recently discovered pulsar PSR J 0205+6449 in the supernova remnant 3C 58) suggest that it can be a young ``ordinary" pulsar.

  18. A medium-deep Chandra and Subaru survey of the 13-h XMM/ROSAT deep survey area

    Science.gov (United States)

    McHardy, I. M.; Gunn, K. F.; Newsam, A. M.; Mason, K. O.; Page, M. J.; Takata, T.; Sekiguchi, K.; Sasseen, T.; Cordova, F.; Jones, L. R.; Loaring, N.

    2003-07-01

    We present the results of a Chandra ACIS-I survey of a high-latitude region at 13 h +38° which was earlier observed with ROSAT and which has recently been observed by XMM-Newton for 200 ks. XMM-Newton will provide good-quality X-ray spectra for over 200 sources with fluxes around the knee of the log N/ log S, which are responsible for the bulk of the X-ray background. The main aim of the Chandra observations is to provide arcsecond, or better, positions, and hence reliable identifications, for the XMM-Newton sources. The ACIS-I observations were arranged in a mosaic of four 30-ks pointings, covering almost all of the 15-arcmin radius XMM-Newton/ROSAT field. We detect 214 Chandra sources above a Cash likelihood statistic of 25, which approximates to 5σ significance, to a limiting flux of ~1.3 × 10-15 erg cm-2 s-1 (0.5-7 keV). Optical counterparts are derived from a Subaru SuprimeCam image reaching to R~ 27. The very large majority of the Chandra sources have an optical counterpart, with the distribution peaking at 23 high LX/Lopt ratios, implying absorption at moderate redshift. Comparison with the earlier ROSAT survey shows that the accuracy of the ROSAT positions agrees very well with the predictions from simulations by McHardy et al. and that the large majority of the identifications were correct.

  19. Discovery of two eclipsing X-ray binaries in M 51

    Science.gov (United States)

    Wang, Song; Soria, Roberto; Urquhart, Ryan; Liu, Jifeng

    2018-04-01

    We discovered eclipses and dips in two luminous (and highly variable) X-ray sources in M 51. One (CXOM51 J132943.3+471135) is an ultraluminous supersoft source, with a thermal spectrum at a temperature of about 0.1 keV and characteristic blackbody radius of about 104 km. The other (CXOM51 J132946.1+471042) has a two-component spectrum with additional thermal-plasma emission; it approached an X-ray luminosity of 1039erg s-1 during outbursts in 2005 and 2012. From the timing of three eclipses in a series of Chandra observations, we determine the binary period (52.75 ± 0.63 hr) and eclipse fraction (22% ± 0.1%) of CXOM51 J132946.1+471042. We also identify a blue optical counterpart in archival Hubble Space Telescope images, consistent with a massive donor star (mass of ˜20-35M⊙). By combining the X-ray lightcurve parameters with the optical constraints on the donor star, we show that the mass ratio in the system must be M_2/M_1 ≳ 18, and therefore the compact object is most likely a neutron star (exceeding its Eddington limit in outburst). The general significance of our result is that we illustrate one method (applicable to high-inclination sources) of identifying luminous neutron star X-ray binaries, in the absence of X-ray pulsations or phase-resolved optical spectroscopy. Finally, we discuss the different X-ray spectral appearance expected from super-Eddington neutron stars and black holes at high viewing angles.

  20. X-RAY PROPERTIES OF YOUNG EARLY-TYPE GALAXIES. I. X-RAY LUMINOSITY FUNCTION OF LOW-MASS X-RAY BINARIES

    International Nuclear Information System (INIS)

    Kim, Dong-Woo; Fabbiano, Giuseppina

    2010-01-01

    We have compared the combined X-ray luminosity function (XLF) of low-mass X-ray binaries (LMXBs) detected in Chandra observations of young, post-merger elliptical galaxies with that of typical old elliptical galaxies. We find that the XLF of the 'young' sample does not present the prominent high-luminosity break at L X > 5 x 10 38 erg s -1 found in the old elliptical galaxy XLF. The 'young' and 'old' XLFs differ with a 3σ statistical significance (with a probability less than 0.2% that they derive from the same underlying parent distribution). Young elliptical galaxies host a larger fraction of luminous LMXBs (L X > 5 x 10 38 erg s -1 ) than old elliptical galaxies and the XLF of the young galaxy sample is intermediate between that of typical old elliptical galaxies and that of star-forming galaxies. This observational evidence may be related to the last major/minor mergers and the associated star formation.

  1. NuSTAR Observations of the Compton-thick Active Galactic Nucleus and Ultraluminous X-Ray Source Candidate in NGC 5643

    Science.gov (United States)

    Annuar, A.; Gandhi, P.; Alexander, D. M.; Lansbury, G. B.; Arévalo, P.; Ballantyne, D. R.; Baloković, M.; Bauer, F. E.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Del Moro, A.; Hailey, C. J.; Harrison, F. A.; Hickox, R. C.; Matt, G.; Puccetti, S.; Ricci, C.; Rigby, J. R.; Stern, D.; Walton, D. J.; Zappacosta, L.; Zhang, W.

    2015-12-01

    We present two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the local Seyfert 2 active galactic nucleus (AGN) and an ultraluminous X-ray source (ULX) candidate in NGC 5643. Together with archival data from Chandra, XMM-Newton, and Swift-BAT, we perform a high-quality broadband spectral analysis of the AGN over two decades in energy (˜0.5-100 keV). Previous X-ray observations suggested that the AGN is obscured by a Compton-thick (CT) column of obscuring gas along our line of sight. However, the lack of high-quality ≳10 keV observations, together with the presence of a nearby X-ray luminous source, NGC 5643 X-1, have left significant uncertainties in the characterization of the nuclear spectrum. NuSTAR now enables the AGN and NGC 5643 X-1 to be separately resolved above 10 keV for the first time and allows a direct measurement of the absorbing column density toward the nucleus. The new data show that the nucleus is indeed obscured by a CT column of NH ≳ 5 × 1024 cm-2. The range of 2-10 keV absorption-corrected luminosity inferred from the best-fitting models is L2-10,int = (0.8-1.7) × 1042 erg s-1, consistent with that predicted from multiwavelength intrinsic luminosity indicators. In addition, we also study the NuSTAR data for NGC 5643 X-1 and show that it exhibits evidence of a spectral cutoff at energy E ˜ 10 keV, similar to that seen in other ULXs observed by NuSTAR. Along with the evidence for significant X-ray luminosity variations in the 3-8 keV band from 2003 to 2014, our results further strengthen the ULX classification of NGC 5643 X-1.

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

    International Nuclear Information System (INIS)

    Fuchs, Matthias

    2010-01-01

    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 ∝17 nm from a compact setup. Undulator spectra were detected in ∝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 ∝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.)

  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. NuSTAR and XMM-Newton Observations of the Hard X-Ray Spectrum of Centaurus A

    DEFF Research Database (Denmark)

    Fürst, F.; Müller, C.; Madsen, K. K.

    2016-01-01

    with an absorbed power-law witha photon index Γ = 1.815 ± 0.005 and a fluorescent Fe Kα line in good agreement with literature values.The spectrum does not require a high-energy exponential rollover, with a constraint of Efold > 1 MeV. Athermal Comptonization continuum describes the data well, with parameters....... We use archival Chandra data to estimatethe contribution from diffuse emission, extra-nuclear point-sources, and the X-ray jet to the observed NuSTAR and XMM-Newton X-ray spectra and find the contribution to be negligible. We discuss different scenarios forthe physical origin of the observed X...

  5. Time-resolved X-ray studies using third generation synchrotron radiation sources

    International Nuclear Information System (INIS)

    Mills, D.M.

    1991-10-01

    The third generation, high-brilliance, hard x-ray, synchrotron radiation (SR) sources currently under construction (ESRF at Grenoble, France; APS at Argonne, Illinois; and SPring-8 at Harima, Japan) will usher in a new era of x-ray experimentation for both physical and biological sciences. One of the most exciting areas of experimentation will be the extension of x-ray scattering and diffraction techniques to the study of transient or time-evolving systems. The high repetition rate, short-pulse duration, high brilliance, and variable spectral bandwidth of these sources make them ideal for x-ray time-resolved studies. The temporal properties (bunch length, interpulse period, etc.) of these new sources will be summarized. Finally, the scientific potential and the technological challenges of time-resolved x-ray scattering from these new sources will be described. 13 refs., 4 figs

  6. Chandra Captures Venus In A Whole New Light

    Science.gov (United States)

    2001-11-01

    Scientists have captured the first X-ray view of Venus using NASA's Chandra X-ray Observatory. The observations provide new information about the atmosphere of Venus and open a new window for examining Earth's sister planet. Venus in X-rays looks similar to Venus in visible light, but there are important differences. The optically visible Venus is due to the reflection of sunlight and, for the relative positions of Venus, Earth and Sun during these observations, shows a uniform half-crescent that is brightest toward the middle. The X-ray Venus is slightly less than a half-crescent and brighter on the limbs. The differences are due to the processes by which Venus shines in visible and X-ray light. The X-rays from Venus are produced by fluorescence, rather than reflection. Solar X-rays bombard the atmosphere of Venus, knock electrons out of the inner parts of the atoms, and excite the atoms to a higher energy level. The atoms almost immediately return to their lower energy state with the emission of a fluorescent X-ray. A similar process involving ultraviolet light produces the visible light from fluorescent lamps. For Venus, most of the fluorescent X-rays come from oxygen and carbon atoms between 120 and 140 kilometers (74 to 87 miles) above the planet's surface. In contrast, the optical light is reflected from clouds at a height of 50 to 70 kilometers (31 to 43 miles). As a result, Venus' Sun-lit hemisphere appears surrounded by an almost-transparent luminous shell in X-rays. Venus looks brightest at the limb since more luminous material is there. Venus X-ray/Optical Composite of Venus Credit: Xray: NASA/CXC/MPE/K.Dennerl et al., Optical: Konrad Dennerl "This opens up the exciting possibility of using X-ray observations to study regions of the atmosphere of Venus that are difficult to investigate by other means," said Konrad Dennerl of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, leader of an international team of scientists that

  7. X-RAY EMISSION FROM MAGNETIC MASSIVE STARS

    International Nuclear Information System (INIS)

    Nazé, Yaël; Petit, Véronique; Rinbrand, Melanie; Owocki, Stan; Cohen, David; Ud-Doula, Asif; Wade, Gregg A.

    2014-01-01

    Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ∼60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- M-dot B stars and flattens for the more luminous, higher- M-dot O stars. As the winds are radiatively driven, these scalings can be equivalently written as relations with the bolometric luminosity. The observed X-ray luminosities, and their trend with mass-loss rates, are well reproduced by new MHD models, although a few overluminous stars (mostly rapidly rotating objects) exist. No relation is found between other X-ray properties (plasma temperature, absorption) and stellar or magnetic parameters, contrary to expectations (e.g., higher temperature for stronger mass-loss rate). This suggests that the main driver for the plasma properties is different from the main determinant of the X-ray luminosity. Finally, variations of the X-ray hardnesses and luminosities, in phase with the stellar rotation period, are detected for some objects and they suggest that some temperature stratification exists in massive stars' magnetospheres

  8. Tire inspection system with shielded x-ray source

    International Nuclear Information System (INIS)

    Heisner, D.N.; Palermo, A. Jr.; Loyer, P.K.

    1976-01-01

    An automated tire inspection system is described which employs a penetrative radiation, such as x-radiation, to inspect the integrity of portions of tires fed sequentially along a feed path through a centering station and into a shielded enclosure where an inspection station is defined. Features of the system include a continuously operating x-ray source movable between inspection and retracted positions, and an x-ray shield for covering the source when it is retracted to permit the doors of the shielded enclosure to be opened without danger from escaping radiation. 19 Claims, 38 Drawing Figures

  9. Examining the X-ray Properties of Lenticular Galaxies: Rollins S0 X-ray Sample (RS0X)

    Science.gov (United States)

    Fuse, Christopher R.; Malespina, Alysa

    2017-01-01

    Lenticular galaxies represent a complex morphology in which many questions remain. The S0 morphology possesses spiral galaxy attributes, such as a disk, while also displaying the luminosity and old stellar population indicative of an elliptical galaxy. The proposed formation mechanisms for lenticulars are also varied, with the absence of gas suggesting a faded spiral and the high masses and luminosities implying a merger formation. The star formation and high-energy emission from a sample of S0s will be used to better understand the properties and formation mechanisms of this unique subset of galaxies.We use the Chandra X-ray Observatory archives cycle 1 - 16 to identify a sample of seventeen lenticular galaxies residing in a variety of environments. Data was analyzed using the CIAO software to produce true color images, radial profiles of the halo gas, gas contours, as well as determine the X-ray luminosities of the point sources and gas.The X-ray gas temperature of the sample S0s varied over a narrow range between 0.61 and 0.96 keV, with one outlier, NGC 4382 at 2.0 keV. The X-ray luminosity of the halo gas varies by four dex. The gas temperatures and X-ray luminosities do not vary by environment, with the majority of sample S0s displaying values of typical elliptical galaxies. The S0 sample is X-ray under-luminous relative to the optical luminosity as compared to the sample of early-type galaxies of Ellis & O’Sullivan (2006).The halo gas exhibited some distinct morphological features, such as multiple X-ray peaks, which may indicate a merger event, and highly concentrated gas, suggesting limited gravitational disturbance. Isolated S0, NGC 4406, displays an asymmetric halo, which could be interpreted as gas stripping. An isolated lenticular experiencing gas redistribution due to gravitational perturbation or a cluster-like medium could be interpreted as NGC 4406 forming in a higher galactic density environment than the field.

  10. CARINA OB STARS: X-RAY SIGNATURES OF WIND SHOCKS AND MAGNETIC FIELDS

    International Nuclear Information System (INIS)

    Gagne, Marc; Fehon, Garrett; Savoy, Michael R.; Cohen, David H.; Townsley, Leisa K.; Broos, Patrick S.; Povich, Matthew S.; Corcoran, Michael F.; Walborn, Nolan R.; Remage Evans, Nancy; Moffat, Anthony F. J.; Naze, Yael; Oskinova, Lida M.

    2011-01-01

    The Chandra Carina Complex contains 200 known O- and B-type stars. The Chandra survey detected 68 of the 70 O stars and 61 of 127 known B0-B3 stars. We have assembled a publicly available optical/X-ray database to identify OB stars that depart from the canonical L X /L bol relation or whose average X-ray temperatures exceed 1 keV. Among the single O stars with high kT we identify two candidate magnetically confined wind shock sources: Tr16-22, O8.5 V, and LS 1865, O8.5 V((f)). The O4 III(fc) star HD 93250 exhibits strong, hard, variable X-rays, suggesting that it may be a massive binary with a period of >30 days. The visual O2 If* binary HD 93129A shows soft 0.6 keV and hard 1.9 keV emission components, suggesting embedded wind shocks close to the O2 If* Aa primary and colliding wind shocks between Aa and Ab. Of the 11 known O-type spectroscopic binaries, the long orbital-period systems HD 93343, HD 93403, and QZ Car have higher shock temperatures than short-period systems such as HD 93205 and FO 15. Although the X-rays from most B stars may be produced in the coronae of unseen, low-mass pre-main-sequence companions, a dozen B stars with high L X cannot be explained by a distribution of unseen companions. One of these, SS73 24 in the Treasure Chest cluster, is a new candidate Herbig Be star.

  11. Stellar Forensics with Striking Image from Chandra

    Science.gov (United States)

    2007-10-01

    A spectacular new image shows how complex a star's afterlife can be. By studying the details of this image made from a long observation by NASA's Chandra X-ray Observatory, astronomers can better understand how some stars die and disperse elements like oxygen into the next generation of stars and planets. At a distance of about 20,000 light years, G292.0+1.8 is one of only three supernova remnants in the Milky Way known to contain large amounts of oxygen. The image shows a rapidly expanding, intricately structured, debris field that contains, along with oxygen, other elements such as neon and silicon that were forged in the star before it exploded. Hard X-ray Image of G292.0+1.8 Hard X-ray Image of G292.0+1.8 "We are finding that, just like snowflakes, each supernova remnant is complicated and beautiful in its own way," said Sangwook Park of Penn State who led the work, released in conjunction with the "8 Years of Chandra" symposium in Huntsville, Ala. The new, deep Chandra image - equaling nearly 6 days worth of observing time - shows an incredibly complex structure. Understanding the details of G292.0+1.8 is especially important because astronomers have considered it to be a "textbook" case of a supernova created by the death of a massive star. Chandra X-ray Image of G292.0+1.8 Chandra X-ray Image of G292.0+1.8 By mapping the distribution of X-rays in different energy bands, the Chandra image traces the distribution of chemical elements ejected in the supernova. The results imply that the explosion was not symmetrical. For example, blue (silicon and sulfur) and green (magnesium) are seen strongly in the upper right, while yellow and orange (oxygen) dominate the lower left. These elements light up at different temperatures, indicating that the temperature is higher in the upper right portion of G292.0+1.8. Slightly below and to the left of the center of G292.0+1.8 is a pulsar, a dense, rapidly rotating neutron star that remained behind after the original star

  12. Discovery of X-Ray Emission from the Crab Pulsar at Pulse Minimum

    Science.gov (United States)

    Tennant, Allyn F.; Becker, Werner; Juda, Michael; Elsner, Ronald F.; Kolodziejczak, Jeffery J.; Murray, Stephen S.; ODell, Stephen L.; Paerels, Frits; Swartz, Douglas A.

    2001-01-01

    The Chandra X-Ray Observatory observed the Crab pulsar using the Low-Energy Transmission Grating with the High-Resolution Camera. Time-resolved zeroth-order images reveal that the pulsar emits X-rays at all pulse phases. Analysis of the flux at minimum - most likely non-thermal in origin - places an upper limit (T(sub infinity) < 2.1 MK) on the surface temperature of the underlying neutron star. In addition, analysis of the pulse profile establishes that the error in the Chandra-determined absolute time is quite small, -0.2 +/- 0.1 ms.

  13. Young and Old X-ray Binary and IXO Populations in Spiral and Elliptical Galaxies

    Science.gov (United States)

    Colbert, E.; Heckman, T.; Ptak, A.; Strickland, D.; Weaver, K.

    2003-03-01

    We have analyzed Chandra ACIS observations of 32 nearby spiral and elliptical galaxies and present the results of 1441 X-ray point sources, which are presumed to be mostly X-ray binaries (XRBs) and Intermediate-luminosity X-ray Objects (IXOs, a.k.a. ULXs). The X-ray luminosity functions (XLFs) of the point sources show that the slope of the elliptical galaxy XLFs are significantly steeper than the spiral galaxy XLFs, indicating grossly different types of point sources, or different stages in their evolution. Since the spiral galaxy XLF is so shallow, the most luminous points sources (usually the IXOs) dominate the total X-ray point source luminosity LXP. We show that the galaxy total B-band and K-band light (proxies for the stellar mass) are well correlated with LXP for both spirals and ellipticals, but the FIR and UV emission is only correlated for the spirals. We deconvolve LXP into two components, one that is proportional to the galaxy stellar mass (pop II), and another that is proportional to the galaxy SFR (pop I). We also note that IXOs (and nearly all of the other point sources) in both spirals and ellipticals have X-ray colors that are most consistent with power-law slopes of Gamma ˜ 1.5--3.0, which is inconsistent with high-mass XRBS (HMXBs). Thus, HMXBs are not important contributors to LXP. We have also found that IXOs in spiral galaxies may have a slightly harder X-ray spectrum than those in elliptical galaxies. The implications of these findings will be discussed.

  14. Characterisation and application of a laser-based hard x-ray source

    International Nuclear Information System (INIS)

    Graetz, M.

    1998-11-01

    Hard X-rays are generated by focusing 110 fs laser pulses with intensities of about 1017 W/cm 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

  15. 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

  16. PSR J2124-3358: A Bow Shock Nebula with an X-ray Tail

    Science.gov (United States)

    Chatterjee, S.; Gaensler, B. M.; Vigelius, M.; Cordes, J. M.; Arzoumanian, Z.; Stappers, B.; Ghavamian, P.; Melatos, A.

    2005-12-01

    As neutron stars move supersonically through the interstellar medium, their relativistic winds are confined by the ram pressure of the interstellar medium. The outer shocked layers may emit in Hα , producing a visible bow shock nebula, while the confined relativistic wind may produce radio or X-ray emission. The Hα bow shock nebula powered by the recycled pulsar J2124-3358 is asymmetric about the velocity vector and shows a marked kink. In recent observations with the Chandra X-ray Observatory, we have detected a long, curved X-ray tail associated with the pulsar. The tail is not aligned with the pulsar velocity, but is confined within the optical bow shock. The X-ray spectrum of the tail is well-fit by a power law, consistent with synchrotron emission from the wind termination shock and the post-shock flow. The presence of Hα and X-ray emission allows us to trace both the external ambient medium and the confined wind. In magnetohydrodynamic simulations, we verify that a bulk flow and non-uniformities in the ambient medium can produce the observed shape of the nebula, possibly in combination with an anisotropic pulsar wind. Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number GO5-6075X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060.

  17. X-Band Linac Beam-Line for Medical Compton Scattering X-Ray Source

    CERN Document Server

    Dobashi, Katsuhiro; Ebina, Futaro; Fukasawa, Atsushi; Hayano, Hitoshi; Higo, Toshiyasu; Kaneyasu, Tatsuo; Ogino, Haruyuki; Sakamoto, Fumito; Uesaka, Mitsuru; Urakawa, Junji; Yamamoto, Tomohiko

    2005-01-01

    Compton scattering hard X-ray source for 10~80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U. Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard ( 10-80

  18. An ultrasoft X-ray source in Coma Berenices

    International Nuclear Information System (INIS)

    Margon, B.; Malina, R.; Bowyer, S.; Cruddace, R.; Lampton, M.

    1976-01-01

    We have observed an intense soft X-ray source with an extraordinary spectrum in Coma Berenices, 4 0 northeast of and unassociated with the Coma cluster of galaxies. Two spectra, obtained at different times in a sounding rocket flight, indicate that the source temperature in thermal models is less than 10 6 K; a power-law model requires photon power-law indices steeper than n=-3. The intensity in the 44--165 A band is of the order of 5x10 -10 ergs cm -2 s -1 , but no flux is present at energies 0.3--2.1 keV to a limit of 1x10 -10 ergs cm -2 s -1 . The lack of bright stars or a supernova remnant in the error box implies that this may be a new class of soft X-ray sources

  19. Rotating anode X-ray source

    International Nuclear Information System (INIS)

    Wittry, D.B.

    1979-01-01

    A rotating anode x-ray source is described which consists of a rotary anode disc including a target ring and a chamber within the anode disc. Liquid is evaporated into the chamber from the target ring to cool the target and a method is provided of removing the latent heat of the vapor. (U.K.)

  20. Sixth symposium on x- and gamma ray sources and applications. Abstracts

    International Nuclear Information System (INIS)

    1985-01-01

    Abstracts are provided for technical presentations in the areas of: gamma and x-ray sources, kinds of detectors, characterization of detectors and detector systems, models and data analysis, gamma spectroscopy, instrumentation, x-ray fluorescence, tomography, x-ray absorption, and pion induced x-ray emission

  1. X-ray constraints on the number of stellar mass black holes in the inner parsec

    Science.gov (United States)

    Deegan, Patrick; Nayakshin, Sergei

    2006-12-01

    Due to dynamical friction stellar mass black holes should form a cusp in the inner parsec. Calculations [5, 6] show that approximately 20 thousand black holes would be present in a sphere with radius of about a parsec around Sgr A*. The presence of these objects opens up the possibility that they might be accreting ''cool'' gas (i.e. the Minispiral) as discussed by Morris [6]. Here we calculate the X-ray emission expected from these black holes as a method to constrain their population. We find that the data limits the total number of such black holes to around 10 - 20 thousand. Even a much smaller number of such black holes, i.e. 5 thousand, is sufficient to produce several sources with X-ray luminosity above Lx ~ 1033 erg s-1 at any one time. We suggest that some of the discrete X-ray sources observed by Muno [7] with Chandra in the inner parsec may be such ''fake X-ray binaries''.

  2. High intensity line source for x-ray spectrometer calibration

    International Nuclear Information System (INIS)

    Thoe, R.S.

    1986-06-01

    A high intensity electron-impact x-ray source using a one-dimensional Pierce lens has been built for the purpose of calibrating a bent crystal x-ray spectrometer. This source focuses up to 100 mA of 20-keV electrons to a line on a liquid-cooled anode. The line (which can serve as a virtual slit for the spectrometer) measures approximately 800 μ x 2 cm. The source is portable and therefore adaptable to numerous types of spectrometer applications. One particular application, the calibration of a high resolution (r = 10 4 ) time-resolved cyrstal spectrometer, will be discussed in detail

  3. Chandra Studies of Planets and Comets in the X-ray

    Science.gov (United States)

    Lisse, Carey; Bhardwaj, A.; Wolk, S. J.; Christian, D. J.; Dennerl, K.; Bodewits, D.; Zurbuchen, T. H.

    2009-09-01

    The discovery of high energy x-ray emission in 1996 from C/1996 B2 (Hyakutake) created a new class of solar system x-ray emitting objects [1]. Subsequent detections of the morphology, spectra, and time dependence of the x-rays from more than 20 comets have shown that the very soft (E Lisse et al., Science 274, 205 (1996)[2] R. Wegmann and K. Dennerl, A&A 430, L33 (2005)[3] D. Bodewits et al., A&A 469, 1183 (2007)[4] A. Bhardwaj et al., PSS 55, 1135 - 1189 (2007)

  4. THE 31 DEG{sup 2} RELEASE OF THE STRIPE 82 X-RAY SURVEY: THE POINT SOURCE CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    LaMassa, Stephanie M.; Urry, C. Megan; Ananna, Tonima; Civano, Francesca; Marchesi, Stefano; Pecoraro, Robert [Yale Center for Astronomy and Astrophysics, Physics Department, P.O. Box 208120, New Haven, CT 06520 (United States); Cappelluti, Nico; Comastri, Andrea; Brusa, Marcella [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Böhringer, Hans; Chon, Gayoung [Max-Planck-Institut für extraterrestrische Physik, D-85748 Garching (Germany); Glikman, Eilat [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States); Richards, Gordon [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Cardamone, Carie [Department of Math and Science, Wheelock College, 200 Riverway, Boston, MA 02215 (United States); Farrah, Duncan [Department of Physics MC 0435, Virginia Polytechnic Institute and State University, 850 West Campus Drive, Blacksburg, VA 24061 (United States); Gilfanov, Marat [Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching (Germany); Green, Paul [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Komossa, S. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Lira, Paulina [Departamento de Astronomia, Universidad de Chile, Camino del Observatorio 1515, Santiago (Chile); Makler, Martin [Centro Brasileiro de Pesquisas Fisicas, Rua Dr Xavier Sigaud 150, Rio de Janeiro, RJ 22290-180 (Brazil); and others

    2016-02-01

    We release the next installment of the Stripe 82 X-ray survey point-source catalog, which currently covers 31.3 deg{sup 2} of the Sloan Digital Sky Survey (SDSS) Stripe 82 Legacy field. In total, 6181 unique X-ray sources are significantly detected with XMM-Newton (>5σ) and Chandra (>4.5σ). This catalog release includes data from XMM-Newton cycle AO 13, which approximately doubled the Stripe 82X survey area. The flux limits of the Stripe 82X survey are 8.7 × 10{sup −16} erg s{sup −1} cm{sup −2}, 4.7 × 10{sup −15} erg s{sup −1} cm{sup −2}, and 2.1 × 10{sup −15} erg s{sup −1} cm{sup −2} in the soft (0.5–2 keV), hard (2–10 keV), and full bands (0.5–10 keV), respectively, with approximate half-area survey flux limits of 5.4 × 10{sup −15} erg s{sup −1} cm{sup −2}, 2.9 × 10{sup −14} erg s{sup −1} cm{sup −2}, and 1.7 × 10{sup −14} erg s{sup −1} cm{sup −2}. We matched the X-ray source lists to available multi-wavelength catalogs, including updated matches to the previous release of the Stripe 82X survey; 88% of the sample is matched to a multi-wavelength counterpart. Due to the wide area of Stripe 82X and rich ancillary multi-wavelength data, including coadded SDSS photometry, mid-infrared WISE coverage, near-infrared coverage from UKIDSS and VISTA Hemisphere Survey, ultraviolet coverage from GALEX, radio coverage from FIRST, and far-infrared coverage from Herschel, as well as existing ∼30% optical spectroscopic completeness, we are beginning to uncover rare objects, such as obscured high-luminosity active galactic nuclei at high-redshift. The Stripe 82X point source catalog is a valuable data set for constraining how this population grows and evolves, as well as for studying how they interact with the galaxies in which they live.

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

    International Nuclear Information System (INIS)

    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 17 W/cm -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

  6. 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.

  7. Development of a sub-MeV X-ray source via Compton backscattering

    International Nuclear Information System (INIS)

    Kawase, K.; Kando, M.; Hayakawa, T.; Daito, I.; Kondo, S.; Homma, T.; Kameshima, T.; Kotaki, H.; Chen, L.-M.; Fukuda, Y.; Faenov, A.; Shizuma, T.; Shimomura, T.; Yoshida, H.; Hajima, R.; Fujiwara, M.; Bulanov, S.V.; Kimura, T.; Tajima, T.

    2011-01-01

    At the Kansai Photon Science Institute of the Japan Atomic Energy Agency, we have developed a Compton backscattered X-ray source in the energy region of a few hundred keV. The X-ray source consists of a 150-MeV electron beam, with a pulse duration of 10 ps (rms), accelerated by a Microtron accelerator and an Nd:YAG laser, with a pulse duration of 10 ns (FWHM). In the first trial experiment, the X-ray flux is estimated to be (2.2±1.0)x10 2 photons/pulse. For the actual application of an X-ray source, it is important to increase the generated X-ray flux as much as possible. Thus, for the purpose of increasing the X-ray flux, we have developed the pulse compression system for the Nd:YAG laser via stimulated Brillouin scattering (SBS). The SBS pulse compression has the great advantages of a high conversion efficiency and a simple structure. In this article, we review the present status of the Compton backscattered X-ray source and describe the SBS pulse compression system.

  8. UNVEILING THE NATURE OF IGR J17177-3656 WITH X-RAY, NEAR-INFRARED, AND RADIO OBSERVATIONS

    International Nuclear Information System (INIS)

    Paizis, A.; Nowak, M. A.; Wilms, J.; Chaty, S.; Corbel, S.; Rodriguez, J.; Del Santo, M.; Ubertini, P.; Chini, R.

    2011-01-01

    We report on the first broadband (1-200 keV) simultaneous Chandra-INTEGRAL observations of the recently discovered hard X-ray transient IGR J17177-3656 that took place on 2011 March 22, about two weeks after the source discovery. The source had an average absorbed 1-200 keV flux of about 8 x 10 -10 erg cm -2 s -1 . We extracted a precise X-ray position of IGR J17177-3656, α J2000 = 17 h 17 m 42. s 62, δ J2000 = -36 0 56'04.''5 (90% uncertainty of 0.''6). We also report Swift, near-infrared, and quasi-simultaneous radio follow-up observations. With the multi-wavelength information at hand, we propose IGR J17177-3656 is a low-mass X-ray binary, seen at high inclination, probably hosting a black hole.

  9. Debris-free soft x-ray source with gas-puff target

    Science.gov (United States)

    Ni, Qiliang; Chen, Bo; Gong, Yan; Cao, Jianlin; Lin, Jingquan; Lee, Hongyan

    2001-12-01

    We have been developing a debris-free laser plasma light source with a gas-puff target system whose nozzle is driven by a piezoelectric crystal membrane. The gas-puff target system can utilize gases such as CO2, O2 or some gas mixture according to different experiments. Therefore, in comparison with soft X-ray source using a metal target, after continuously several-hour laser interaction with gas from the gas-puff target system, no evidences show that the light source can produce debris. The debris-free soft X-ray source is prepared for soft X-ray projection lithography research at State Key Laboratory of Applied Optics. Strong emission from CO2, O2 and Kr plasma is observed.

  10. Searching for Exoplanet Effects on the X-ray Spectrum of τ Boo

    Science.gov (United States)

    Wood, Brian; Laming, J. Martin

    2018-01-01

    We study the X-ray spectrum of the exoplanet host star τ Boo A (F7 V), in order to explore the possibility that its very close-in, massive exoplanet (Porb=3.31 days, m sin i=3.9 MJ) may be affecting the coronal emissions of this star. The star was observed recently by Chandra/LETGS for 92 ksec in three pieces between 2017 February 27 and 2017 March 5; and was previously observed by XMM for 65 ksec in 2003 June 24. The new Chandra observations allow us to resolve τ Boo A from its stellar companion, τ Boo B (M2 V), for the first time. The companion accounts for 21% of the system's total X-ray emission at the time of the Chandra observation. Nevertheless, our measurements of τ Boo A emission measures and coronal abundances from Chandra are reasonably consistent with previous measurements from XMM by Maggio et al. (2011, A&A, 527, A144), in which τ Boo A and B are not resolved. Covering planetary orbital phases 0.21-0.31, 0.44-0.49, and 0.69-0.86, the Chandra data show that τ Boo A's coronal X-ray spectrum does not vary significantly with planetary orbital phase. However, our analysis suggests that coronal abundances for τ Boo A are somewhat anomalous, with a significantly weaker "FIP effect" compared to similar stars without close-in exoplanets, particularly π3 Ori (F6 V).

  11. 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 cover...

  12. Sources of the X-rays Based on Compton Scattering

    International Nuclear Information System (INIS)

    Androsov, V.; Bulyak, E.; Gladkikh, P.; Karnaukhov, I.; Mytsykov, A.; Telegin, Yu.; Shcherbakov, A.; Zelinsky, A.

    2007-01-01

    The principles of the intense X-rays generation by laser beam scattering on a relativistic electron beam are described and description of facilities assigned to produce the X-rays based on Compton scattering is presented. The possibilities of various types of such facilities are estimated and discussed. The source of the X-rays based on a storage ring with low beam energy is described in details and advantages of the sources of such type are discussed.The results of calculation and numerical simulation carried out for laser electron storage ring NESTOR that is under development in NSC KIPT show wide prospects of the accelerator facility of such type

  13. 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.

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

    International Nuclear Information System (INIS)

    Lo, Kitty K.; Farrell, Sean; 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 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.

  15. Intensity-Modulated Advanced X-ray Source (IMAXS) for Homeland Security Applications

    International Nuclear Information System (INIS)

    Langeveld, Willem G. J.; Johnson, William A.; Owen, Roger D.; Schonberg, Russell G.

    2009-01-01

    X-ray cargo inspection systems for the detection and verification of threats and contraband require high x-ray energy and high x-ray intensity to penetrate dense cargo. On the other hand, low intensity is desirable to minimize the radiation footprint. A collaboration between HESCO/PTSE Inc., Schonberg Research Corporation and Rapiscan Laboratories, Inc. has been formed in order to design and build an Intensity-Modulated Advanced X-ray Source (IMAXS). Such a source would allow cargo inspection systems to achieve up to two inches greater imaging penetration capability, while retaining the same average radiation footprint as present fixed-intensity sources. Alternatively, the same penetration capability can be obtained as with conventional sources with a reduction of the average radiation footprint by about a factor of three. The key idea is to change the intensity of the source for each x-ray pulse based on the signal strengths in the inspection system detector array during the previous pulse. In this paper we describe methods to accomplish pulse-to-pulse intensity modulation in both S-band (2998 MHz) and X-band (9303 MHz) linac sources, with diode or triode (gridded) electron guns. The feasibility of these methods has been demonstrated. Additionally, we describe a study of a shielding design that would allow a 6 MV X-band source to be used in mobile applications.

  16. X-Ray Processing of ChaMPlane Fields: Methods and Initial Results for Selected Anti-Galactic Center Fields

    Science.gov (United States)

    Hong, JaeSub; van den Berg, Maureen; Schlegel, Eric M.; Grindlay, Jonathan E.; Koenig, Xavier; Laycock, Silas; Zhao, Ping

    2005-12-01

    We describe the X-ray analysis procedure of the ongoing Chandra Multiwavelength Plane (ChaMPlane) Survey and report the initial results from the analysis of 15 selected anti-Galactic center observations (90degusing custom-developed analysis tools appropriate for Galactic sources but also of general use: optimum photometry in crowded fields using advanced techniques for overlapping sources, rigorous astrometry and 95% error circles for combining X-ray images or matching to optical/IR images, and application of quantile analysis for spectral analysis of faint sources. We apply these techniques to 15 anti-Galactic center observations (of 14 distinct fields), in which we have detected 921 X-ray point sources. We present logN-logS distributions and quantile analysis to show that in the hard band (2-8 keV) active galactic nuclei dominate the sources. Complete analysis of all ChaMPlane anti-Galactic center fields will be given in a subsequent paper, followed by papers on sources in the Galactic center and bulge regions.

  17. Liquid-metal-jet anode electron-impact x-ray source

    International Nuclear Information System (INIS)

    Hemberg, O.; Otendal, M.; Hertz, H.M.

    2003-01-01

    We demonstrate an anode concept, based on a liquid-metal jet, for improved brightness in compact electron-impact x-ray sources. The source is demonstrated in a proof-of-principle experiment where a 50 keV, ∼100 W electron beam is focused on a 75 μm liquid-solder jet. The generated x-ray flux and brightness is quantitatively measured in the 7-50 keV spectral region and found to agree with theory. Compared to rotating-anode sources, whose brightness is limited by intrinsic thermal properties, the liquid-jet anode could potentially be scaled to achieve a brightness >100x higher than current state-of-the-art sources. Applications such as mammography, angiography, and diffraction would benefit from such a compact high-brightness source

  18. A FOCUSED, HARD X-RAY LOOK AT ARP 299 WITH NuSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Ptak, A.; Hornschemeier, A.; Lehmer, B.; Yukita, M.; Wik, D.; Tatum, M. [NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Zezas, A. [Department of Physics, University of Crete, Herakleion (Greece); Antoniou, V. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Argo, M. K. [Jodrell Bank Centre for Astrophysics, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Ballo, L.; Della Ceca, R. [Osservatorio Astronomico di Brera (INAF), via Brera 28, I-20121 Milano (Italy); Bechtol, K. [Kavli Institute for Cosmological Physics, Chicago, IL 60637 (United States); Boggs, S.; Craig, W. W.; Krivonos, R. [U.C. Berkeley Space Sciences Laboratory, Berkeley, CA (United States); Christensen, F. E. [National Space Institute, Technical University of Denmark, DK-2100 Copenhagen (Denmark); Hailey, C. J. [Columbia University, New York, NY (United States); Harrison, F. A. [Caltech Division of Physics, Mathematics and Astronomy, Pasadena, CA (United States); Maccarone, T. J. [Department of Physics, Texas Tech University, Lubbock, TX 79409 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); and others

    2015-02-20

    We report on simultaneous observations of the local starburst system Arp 299 with NuSTAR and Chandra, which provides the first resolved images of this galaxy up to energies of ∼45 keV. Fitting the 3-40 keV spectrum reveals a column density of N {sub H} ∼ 4 × 10{sup 24} cm{sup –2}, characteristic of a Compton-thick active galactic nucleus (AGN), and a 10-30 keV luminosity of 1.2 × 10{sup 43} erg s{sup –1}. The hard X-rays detected by NuSTAR above 10 keV are centered on the western nucleus, Arp 299-B, which previous X-ray observations have shown to be the primary source of neutral Fe-K emission. Other X-ray sources, including Arp 299-A, the eastern nucleus also thought to harbor an AGN, as well as X-ray binaries, contribute ≲ 10% to the 10-20 keV emission from the Arp 299 system. The lack of significant emission above 10 keV other than that attributed to Arp 299-B suggests that: (1) any AGN in Arp 299-A must be heavily obscured (N {sub H} > 10{sup 24} cm{sup –2}) or have a much lower luminosity than Arp 299-B and (2) the extranuclear X-ray binaries have spectra that cut-off above ∼10 keV. Such soft spectra are characteristic of ultraluminous X-ray sources observed to date by NuSTAR.

  19. Toward a fourth-generation X-ray source

    International Nuclear Information System (INIS)

    Monction, D. E.

    1999-01-01

    The field of synchrotron radiation research has grown rapidly over the last 25 years due to both the push of the accelerator and magnet technology that produces the x-ray beams and the pull of the extraordinary scientific research that is possible with them. Three successive generations of synchrotrons radiation facilities have resulted in beam brilliances 11 to 12 orders of magnitude greater than the standard laboratory x-ray tube. However, greater advances can be easily imagined given the fact that x-ray beams from present-day facilities do not exhibit the coherence or time structure so familiar with the optical laser. Theoretical work over the last ten years or so has pointed to the possibility of generating hard x-ray beams with laser-like characteristics. The concept is based on self-amplified spontaneous emission (SASE) in flee-electron lasers. A major facility of this type based upon a superconducting linac could produce a cost-effective facility that spans wave-lengths from the ultraviolet to the hard x-ray regime, simultaneously servicing large numbers experimenters from a wide range of disciplines. As with each past generation of synchrotrons facilities, immense new scientific opportunities would result from fourth-generation sources.

  20. Dense plasma focus x-ray source for sub-micron lithography

    International Nuclear Information System (INIS)

    Prasad, R.R.; Krishnan, M.; Mangano, J.; Greene, P.; Qi, Niansheng

    1993-01-01

    A discharge driven, dense plasma focus in neon is under development at SRL for use as a point x-ray source for sub-micron lithography. This source is presently capable of delivering ∼ 13j/pulse of neon K-shell x-rays (8--14 angstrom) into 4π steradians with 2 kj of electrical energy stored in the capacitor bank charged to 9 kV at a pulse repetition rate of 2 Hz. The discharge is produced by a ≤4 kj, ≤12 kV, capacitor bank circuit, which has a fixed inductance of 12 nH and drives ≤450 kA currents into the DPF load, with ∼1.1 μs rise-times. X-rays are produced when a dense pinch of neon is formed along the axis of the DPF electrodes. A new rail-gap switched capacitor bank and DPF have been built, designed for continuous operation at 2 Hz and burst mode operation at 20 Hz. This paper will present measurements of the x-ray output at a repetition rate of 2 Hz using the new capacitor bank. It will also describe measurements of the spot size (0.3--0.8 mm) and the spectrum (8--14 angstrom) of the DPF source. The dependence of these parameters on the DPF head geometry, bank energy and operating pressure will be discussed. The x-ray output has been measured using filtered pin diodes, x-ray diodes, and absolutely calibrated x-ray crystal spectra. Results from the source operating at 2 Hz will be presented. A novel concept of a windowless beamline has also been developed. The results of preliminary experiments to test the concept will be discussed. At a pulse repetition rate of 20 Hz, this source should produce 200--400 W of x-ray power in the 8-14 angstrom wavelength band, with an input power of 40--60 kW

  1. The X-ray Variability of Eta Car, 1996-2010

    Science.gov (United States)

    Corcoran, Michael F.; Hamaguchi, K.; Gull, T.; Owocki, S.; Pittard, J.

    2010-01-01

    X-ray photometry in the 2-10 keY band of the the supermassive binary star Eta Car has been measured with the Rossi X-ray Timing Explorer from 1996-2010. The ingress to X-ray minimum is consistent with a period of 2024 days. The 2009 X-ray minimum began on January 162009 and showed an unexpectedly abrupt recovery starting after 12 Feb 2009. The X-ray colors become harder about half-way through all three minima and continue until flux recovery. The behavior of the fluxes and X-ray colors for the most recent X-ray minimum, along with Chandra high resolution grating spectra at key phases suggests a significant change in the inner wind of Eta Car, a possible indicator that the star is entering a new unstable phase of mass loss.

  2. THE SPECTACULAR RADIO-NEAR-IR-X-RAY JET OF 3C 111: THE X-RAY EMISSION MECHANISM AND JET KINEMATICS

    Energy Technology Data Exchange (ETDEWEB)

    Clautice, Devon; Perlman, Eric S. [Department of Physics and Space Sciences, Florida Institute of Technology, 150 W. University Boulevard, Melbourne, FL 32901 (United States); Georganopoulos, Markos [Department of Physics, University of Maryland—Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Lister, Matthew L.; Hogan, Brandon [Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Tombesi, Francesco [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Cara, Mihai [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Marshall, Herman L. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Kazanas, Demos [NASA’s Goddard Space Flight Center, Astrophysics Science Division, Code 663, Greenbelt, MD 20771 (United States)

    2016-08-01

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

  3. X-ray astronomy

    International Nuclear Information System (INIS)

    Giacconi, R.; Gursky, H.

    1974-01-01

    This text contains ten chapters and three appendices. Following an introduction, chapters two through five deal with observational techniques, mechanisms for the production of x rays in a cosmic setting, the x-ray sky and solar x-ray emission. Chapters six through ten include compact x-ray sources, supernova remnants, the interstellar medium, extragalactic x-ray sources and the cosmic x-ray background. Interactions of x rays with matter, units and conversion factors and a catalog of x-ray sources comprise the three appendices. (U.S.)

  4. CHANDRA, KECK, AND VLA OBSERVATIONS OF THE CRAB NEBULA DURING THE 2011-APRIL GAMMA-RAY FLARE

    Energy Technology Data Exchange (ETDEWEB)

    Weisskopf, Martin C.; Tennant, Allyn F.; O' Dell, Stephen L. [NASA Marshall Space Flight Center, Astrophysics Office (ZP12), Huntsville, AL 35812 (United States); Arons, Jonathan [Astronomy Department and Theoretical Astrophysics Center, University of California, Berkeley, 601 Campbell Hall, Berkeley, CA 94720 (United States); Blandford, Roger; Funk, Stefan; Romani, Roger W. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Buehler, Rolf [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Caraveo, Patrizia; De Luca, Andrea [INAF-IASF Milano, via E. Bassini 15, I-20133 Milano (Italy); Cheung, Chi C. [National Research Council Research Associate, National Academy of Sciences, Washington, DC 20001 (United States); Costa, Enrico [INFN Roma Tor Vergata, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Ferrigno, Carlo [ISDC, Data Center for Astrophysics of the University of Geneva, chemin d' cogia 16, CH-1290 Versoix (Switzerland); Fu, Hai [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Habermehl, Moritz; Horns, Dieter [Institut fuer Experimentalphysik, Universitaet Hamburg, Luruper Chaussee 149, D-22761 Hamburg (Germany); Linford, Justin D. [Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131-0001 (United States); Lobanov, Andrei [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Max, Claire [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Mignani, Roberto [Mullard Space Science Laboratory, University College London, Holmbury St. Mary Dorking, Surrey RH5 6NT (United Kingdom); and others

    2013-03-01

    We present results from our analysis of Chandra X-Ray Observatory, W. M. Keck Observatory, and Karl G. Jansky Very Large Array (VLA) images of the Crab Nebula that were contemporaneous with the {gamma}-ray flare of 2011 April. Despite hints in the X-ray data, we find no evidence for statistically significant variations that pinpoint the specific location of the flares within the Nebula. The Keck observations extend this conclusion to the 'inner knot', i.e., the feature within an arcsecond of the pulsar. The VLA observations support this conclusion. We also discuss theoretical implications of the {gamma}-ray flares and suggest that the most dramatic {gamma}-ray flares are due to radiation-reaction-limited synchrotron emission associated with sudden, dissipative changes in the current system sustained by the central pulsar.

  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. CHANDRA OBSERVATION OF POLARIS: CENSUS OF LOW-MASS COMPANIONS

    International Nuclear Information System (INIS)

    Remage Evans, Nancy; Wolk, Scott J.; Karovska, Margarita; Spitzbart, Bradley; Guinan, Edward; Engle, Scott; Schlegel, Eric; Mason, Brian D.

    2010-01-01

    We have observed Cepheid Polaris (α UMi A: F7 Ib [Aa] + F6 V [Ab]) with Chandra ACIS-I for 10 ks. An X-ray source was found at the location of Polaris with log L X = 28.89 erg s -1 (0.3-8 keV) and kT = 0.6 keV. A spectrum this soft could come from either the supergiant or the dwarf, as shown by comparable coronal stars. Two resolved low-mass visual companions, 'C' and 'D', are not physical members of the system based on the lack of X-rays (indicating an age older than the Cepheid) and inconsistent proper motions. Polaris B is not an X-ray source, consistent with its early F spectral type, and probably does not have a lower mass companion itself. A possible more distant member is identified, and an additional less plausible one. This provides a complete census of companions out to 0.1 pc covering a mass ratio range of an order of magnitude and a ΔV of nearly 15 mag.

  7. Finding counterparts for all-sky X-ray surveys with NWAY: a Bayesian algorithm for cross-matching multiple catalogues

    Science.gov (United States)

    Salvato, M.; Buchner, J.; Budavári, T.; Dwelly, T.; Merloni, A.; Brusa, M.; Rau, A.; Fotopoulou, S.; Nandra, K.

    2018-02-01

    We release the AllWISE counterparts and Gaia matches to 106 573 and 17 665 X-ray sources detected in the ROSAT 2RXS and XMMSL2 surveys with |b| > 15°. These are the brightest X-ray sources in the sky, but their position uncertainties and the sparse multi-wavelength coverage until now rendered the identification of their counterparts a demanding task with uncertain results. New all-sky multi-wavelength surveys of sufficient depth, like AllWISE and Gaia, and a new Bayesian statistics based algorithm, NWAY, allow us, for the first time, to provide reliable counterpart associations. NWAY extends previous distance and sky density based association methods and, using one or more priors (e.g. colours, magnitudes), weights the probability that sources from two or more catalogues are simultaneously associated on the basis of their observable characteristics. Here, counterparts have been determined using a Wide-field Infrared Survey Explorer (WISE) colour-magnitude prior. A reference sample of 4524 XMM/Chandra and Swift X-ray sources demonstrates a reliability of ∼94.7 per cent (2RXS) and 97.4 per cent (XMMSL2). Combining our results with Chandra-COSMOS data, we propose a new separation between stars and AGN in the X-ray/WISE flux-magnitude plane, valid over six orders of magnitude. We also release the NWAY code and its user manual. NWAY was extensively tested with XMM-COSMOS data. Using two different sets of priors, we find an agreement of 96 per cent and 99 per cent with published Likelihood Ratio methods. Our results were achieved faster and without any follow-up visual inspection. With the advent of deep and wide area surveys in X-rays (e.g. SRG/eROSITA, Athena/WFI) and radio (ASKAP/EMU, LOFAR, APERTIF, etc.) NWAY will provide a powerful and reliable counterpart identification tool.

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

    Science.gov (United States)

    2003-09-01

    stars along the way. Scant evidence has been found for such a flow of cool gas or star formation. This forced astronomers to invent several different ways to explain why the gas contained in clusters remained hot, and, until now, none of them was satisfactory. perseus animation Animation of Sound Waves Generated in Perseus Cluster of Ripples in Perseus Heating caused by a central black hole has long been considered a good way to prevent cluster gas from cooling. Although jets have been observed at radio wavelengths, their effect on cluster gas was unclear since this gas is only detectable in X-rays, and early X-ray observations did not have Chandra's ability to find detailed structure. Previous Chandra observations of the Perseus cluster showed two vast, bubble-shaped cavities in the cluster gas extending away from the central black hole. Jets of material pushing back the cluster gas have formed these X-ray cavities, which are bright sources of radio waves. They have long been suspected of heating the surrounding gas, but the mechanism was unknown. The sound waves, seen spreading out from the cavities in the recent Chandra observation, could provide this heating mechanism. A tremendous amount of energy is needed to generate the cavities, as much as the combined energy from 100 million supernovae. Much of this energy is carried by the sound waves and should dissipate in the cluster gas, keeping the gas warm and possibly preventing a cooling flow. If so, the B-flat pitch of the sound wave, 57 octaves below middle-C, would have remained roughly constant for about 2.5 billion years. Perseus is the brightest cluster of galaxies in X-rays, and therefore was a perfect Chandra target for finding sound waves rippling through the hot cluster gas. Other clusters show X-ray cavities, and future Chandra observations may yet detect sound waves in these objects.

  9. X-Ray Calorimeter Arrays for Astrophysics

    Science.gov (United States)

    Kilbourne, Caroline A.

    2009-01-01

    High-resolution x-ray spectroscopy is a powerful tool for studying the evolving universe. The grating spectrometers on the XMM and Chandra satellites started a new era in x-ray astronomy, but there remains a need for instrumentation that can provide higher spectral resolution with high throughput in the Fe-K band (around 6 keV) and can enable imaging spectroscopy of extended sources, such as supernova remnants and galaxy clusters. The instrumentation needed is a broad-band imaging spectrometer - basically an x-ray camera that can distinguish tens of thousands of x-ray colors. The potential benefits to astrophysics of using a low-temperature calorimeter to determine the energy of an incident x-ray photon via measurement of a small change in temperature was first articulated by S. H. Moseley over two decades ago. In the time since, technological progress has been steady, though full realization in an orbiting x-ray telescope is still awaited. A low-temperature calorimeter can be characterized by the type of thermometer it uses, and three types presently dominate the field. The first two types are temperature-sensitive resistors - semiconductors in the metal-insulator transition and superconductors operated in the superconducting-normal transition. The third type uses a paramagnetic thermometer. These types can be considered the three generations of x-ray calorimeters; by now each has demonstrated a resolving power of 2000 at 6 keV, but only a semiconductor calorimeter system has been developed to spaceflight readiness. The Soft X-ray Spectrometer on Astro-H, expected to launch in 2013, will use an array of silicon thermistors with I-IgTe x-ray absorbers that will operate at 50 mK. Both the semiconductor and superconductor calorimeters have been implemented in small arrays, kilo-pixel arrays of the superconducting calorimeters are just now being produced, and it is anticipated that much larger arrays will require the non-dissipative advantage of magnetic thermometers.

  10. The supersoft X-ray source in V5116 Sagittarii. I. The high resolution spectra

    Science.gov (United States)

    Sala, G.; Ness, J. U.; Hernanz, M.; Greiner, J.

    2017-05-01

    Context. Classical nova explosions occur on the surface of an accreting white dwarf in a binary system. After ejection of a fraction of the envelope and when the expanding shell becomes optically thin to X-rays, a bright source of supersoft X-rays arises, powered by residual H burning on the surface of the white dwarf. While the general picture of the nova event is well established, the details and balance of accretion and ejection processes in classical novae are still full of unknowns. The long-term balance of accreted matter is of special interest for massive accreting white dwarfs, which may be promising supernova Ia progenitor candidates. Nova V5116 Sgr 2005b was observed as a bright and variable supersoft X-ray source by XMM-Newton in March 2007, 610 days after outburst. The light curve showed a periodicity consistent with the orbital period. During one third of the orbit the luminosity was a factor of seven brighter than during the other two thirds of the orbital period. Aims: In the present work we aim to disentangle the X-ray spectral components of V5116 Sgr and their variability. Methods: We present the high resolution spectra obtained with XMM-Newton RGS and Chandra LETGS/HRC-S in March and August 2007. Results: The grating spectrum during the periods of high-flux shows a typical hot white dwarf atmosphere dominated by absorption lines of N VI and N VII. During the low-flux periods, the spectrum is dominated by an atmosphere with the same temperature as during the high-flux period, but with several emission features superimposed. Some of the emission lines are well modeled with an optically thin plasma in collisional equilibrium, rich in C and N, which also explains some excess in the spectra of the high-flux period. No velocity shifts are observed in the absorption lines, with an upper limit set by the spectral resolution of 500 km s-1, consistent with the expectation of a non-expanding atmosphere so late in the evolution of the post-nova. Based on

  11. X-ray sky

    International Nuclear Information System (INIS)

    Gruen, M.; Koubsky, P.

    1977-01-01

    The history is described of the discoveries of X-ray sources in the sky. The individual X-ray detectors are described in more detail, i.e., gas counters, scintillation detectors, semiconductor detectors, and the principles of X-ray spectrometry and of radiation collimation aimed at increased resolution are discussed. Currently, over 200 celestial X-ray sources are known. Some were identified as nebulae, in some pulsations were found or the source was identified as a binary star. X-ray bursts of novae were also observed. The X-ray radiation is briefly mentioned of spherical star clusters and of extragalactic X-ray sources. (Oy)

  12. NASA's Chandra Finds Black Holes Are "Green"

    Science.gov (United States)

    2006-04-01

    Black holes are the most fuel efficient engines in the Universe, according to a new study using NASA's Chandra X-ray Observatory. By making the first direct estimate of how efficient or "green" black holes are, this work gives insight into how black holes generate energy and affect their environment. The new Chandra finding shows that most of the energy released by matter falling toward a supermassive black hole is in the form of high-energy jets traveling at near the speed of light away from the black hole. This is an important step in understanding how such jets can be launched from magnetized disks of gas near the event horizon of a black hole. Illustration of Fuel for a Black Hole Engine Illustration of Fuel for a Black Hole Engine "Just as with cars, it's critical to know the fuel efficiency of black holes," said lead author Steve Allen of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University, and the Stanford Linear Accelerator Center. "Without this information, we cannot figure out what is going on under the hood, so to speak, or what the engine can do." Allen and his team used Chandra to study nine supermassive black holes at the centers of elliptical galaxies. These black holes are relatively old and generate much less radiation than quasars, rapidly growing supermassive black holes seen in the early Universe. The surprise came when the Chandra results showed that these "quiet" black holes are all producing much more energy in jets of high-energy particles than in visible light or X-rays. These jets create huge bubbles, or cavities, in the hot gas in the galaxies. Animation of Black Hole in Elliptical Galaxy Animation of Black Hole in Elliptical Galaxy The efficiency of the black hole energy-production was calculated in two steps: first Chandra images of the inner regions of the galaxies were used to estimate how much fuel is available for the black hole; then Chandra images were used to estimate the power required to produce

  13. X-Pinch soft x-ray source for microlithography

    International Nuclear Information System (INIS)

    Glidden, S.C.; Hammer, D.A.; Kalantar, D.H.; Qi, N.

    1993-01-01

    The x-pinch soft x-ray source is described for application in submicron resolution lithography. Experiments have been performed to characterize the radiation emitted from magnesium wire x-pinch plasmas using an 80 ns, ≤500 kA pulse. Yields of 14.2 J averaged over three independent calibrated diagnostics at 445 kA have been measured in magnesium K-shell radiation (predominantly 8.4 angstrom to 9.4 angstrom or 1.5 keV to 1.3 keV) from a submillimeter source, with as little as 5-10% of the yield below the 6.74 angstrom silicon absorption edge. A new ≤700 kA, 100 ns pulser being used for x-pinch physics experiments is described. The design of a 40 pulse per second pulsed power system and wire loading mechanism for exposing a resist in 1 second at a distance 40 cm is presented

  14. Production of hollow atoms by high brightness x-ray sources and its applications

    International Nuclear Information System (INIS)

    Moribayashi, Kengo

    2004-01-01

    We study x-ray emissions from the (multi-)inner-shell states and hollow atoms of Si ions excited by high intensity x-ray sources. It is found that the x-ray number from multi-inner-shell excited states (1s 2 2s 2 2p k 3s 2 3p 2 , k=1-4) and hollow atoms (1s 2 2s 2 3p 2 ) is affected greatly by the high intensity short-pulse x-rays and little by weak intensity post-long pulse x-rays. The ratio of the x-ray intensities from hollow atoms to those from the multi-inner-shell excited states becomes almost independent of the pulses and dependent on the intensities of x-ray sources. This ratio may be used for the measurement of intensities of high intensity short pulse x-ray sources. (author)

  15. Formation and Evolution of X-ray Binaries

    Science.gov (United States)

    Fragkos, Anastasios

    X-ray binaries - mass-transferring binary stellar systems with compact object accretors - are unique astrophysical laboratories. They carry information about many complex physical processes such as star formation, compact object formation, and evolution of interacting binaries. My thesis work involves the study of the formation and evolution of Galactic and extra-galacticX-ray binaries using both detailed and realistic simulation tools, and population synthesis techniques. I applied an innovative analysis method that allows the reconstruction of the full evolutionary history of known black hole X-ray binaries back to the time of compact object formation. This analysis takes into account all the available observationally determined properties of a system, and models in detail four of its evolutionary evolutionary phases: mass transfer through the ongoing X-ray phase, tidal evolution before the onset of Roche-lobe overflow, motion through the Galactic potential after the formation of the black hole, and binary orbital dynamics at the time of core collapse. Motivated by deep extra-galactic Chandra survey observations, I worked on population synthesis models of low-mass X-ray binaries in the two elliptical galaxies NGC3379 and NGC4278. These simulations were targeted at understanding the origin of the shape and normalization of the observed X-ray luminosity functions. In a follow up study, I proposed a physically motivated prescription for the modeling of transient neutron star low-mass X-ray binary properties, such as duty cycle, outburst duration and recurrence time. This prescription enabled the direct comparison of transient low-mass X-ray binary population synthesis models to the Chandra X-ray survey of the two ellipticals NGC3379 and NGC4278. Finally, I worked on population synthesismodels of black holeX-ray binaries in the MilkyWay. This work was motivated by recent developments in observational techniques for the measurement of black hole spin magnitudes in

  16. X-band RF gun and linac for medical Compton scattering X-ray source

    International Nuclear Information System (INIS)

    Dobashi, Katsuhito; Uesaka, Mitsuru; Fukasawa, Atsushi; Sakamoto, Fumito; Ebina, Futaro; Ogino, Haruyuki; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Hayano, Hitoshi; Nakagawa, Keiichi

    2004-01-01

    Compton scattering hard X-ray source for 10-80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U.Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard (10-80 keV) X-rays with the intensities of 108-1010 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at a beam dump by adopting the deceleration of electrons after the Compton scattering. This realizes one beamline of a 3rd generation SR source at small facilities without heavy shielding. The final goal is that the linac and laser are installed on the moving gantry. We have designed the X-band (11.424 GHz) traveling-wave-type linac for the purpose. Numerical consideration by CAIN code and luminosity calculation are performed to estimate the X-ray yield. X-band thermionic-cathode RF-gun and RDS(Round Detuned Structure)-type X-band accelerating structure are applied to generate 50 MeV electron beam with 20 pC microbunches (104) for 1 microsecond RF macro-pulse. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2 J/10 ns is 107 photons/RF-pulse (108 photons/sec at 10 pps). We design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). 50 MW X-band klystron and compact modulator have been constructed and now under tuning. The construction of the whole system has started. X-ray generation and medical application will be performed in the early next year

  17. X-band RF gun and linac for medical Compton scattering X-ray source

    Science.gov (United States)

    Dobashi, Katsuhito; Uesaka, Mitsuru; Fukasawa, Atsushi; Sakamoto, Fumito; Ebina, Futaro; Ogino, Haruyuki; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Hayano, Hitoshi; Nakagawa, Keiichi

    2004-12-01

    Compton scattering hard X-ray source for 10-80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U.Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard (10-80 keV) X-rays with the intensities of 108-1010 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at a beam dump by adopting the deceleration of electrons after the Compton scattering. This realizes one beamline of a 3rd generation SR source at small facilities without heavy shielding. The final goal is that the linac and laser are installed on the moving gantry. We have designed the X-band (11.424 GHz) traveling-wave-type linac for the purpose. Numerical consideration by CAIN code and luminosity calculation are performed to estimate the X-ray yield. X-band thermionic-cathode RF-gun and RDS(Round Detuned Structure)-type X-band accelerating structure are applied to generate 50 MeV electron beam with 20 pC microbunches (104) for 1 microsecond RF macro-pulse. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2 J/10 ns is 107 photons/RF-pulse (108 photons/sec at 10 pps). We design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). 50 MW X-band klystron and compact modulator have been constructed and now under tuning. The construction of the whole system has started. X-ray generation and medical application will be performed in the early next year.

  18. Initial Performance of the Aspect System on the Chandra Observatory: Post-Facto Aspect Reconstruction

    Science.gov (United States)

    Aldcroft, T.; Karovska, M.; Cresitello-Dittmar, M.; Cameron, R.

    2000-01-01

    The aspect system of the Chandra Observatory plays a key role in realizing the full potential of Chandra's x-ray optics and detectors. To achieve the highest spatial and spectral resolution (for grating observations), an accurate post-facto time history of the spacecraft attitude and internal alignment is needed. The CXC has developed a suite of tools which process sensor data from the aspect camera assembly and gyroscopes, and produce the spacecraft aspect solution. In this poster, the design of the aspect pipeline software is briefly described, followed by details of aspect system performance during the first eight months of flight. The two key metrics of aspect performance are: image reconstruction accuracy, which measures the x-ray image blurring introduced by aspect; and celestial location, which is the accuracy of detected source positions in absolute sky coordinates.

  19. Characterization of a pulsed x-ray source for fluorescent lifetime measurements

    International Nuclear Information System (INIS)

    Blankespoor, S.C.; Derenzo, S.E.; Moses, W.W.; Rossington, C.S.; Ito, M.; Oba, K.

    1994-01-01

    To search for new, fast, inorganic scintillators, the authors have developed a bench-top pulsed x-ray source for determining fluorescent lifetimes and wavelengths of compounds in crystal or powdered form. This source uses a light-excited x-ray tube which produces x-rays when light from a laser diode strikes its photocathode. The x-ray tube has a tungsten anode, a beryllium exit window, a 30 kV maximum tube bias, and a 50 μA maximum average cathode current. The laser produces 3 x 10 7 photons at 650 nm per ∼100 ps pulse, with up to 10 7 pulses/sec. The time spread for the laser diode, x-ray tube, and a microchannel plate photomultiplier tube is less than 120 ps fwhm. The mean x-ray energy at tube biases of 20, 25, and 30 kV is 9.4, 10.3, and 11.1 keV, respectively. The authors measured 140, 230, and 330 x-ray photons per laser diode pulse per steradian, at tube biases of 20, 25, and 30 kV, respectively. Background x-rays due to dark current occur at a rate of 1 x 10 6 and 3 x 10 6 photons/sec/steradian at biases of 25 and 30 kV, respectively. Data characterizing the x-ray output with an aluminum filter in the x-ray beam are also presented

  20. X-ray constraints on the number of stellar mass black holes in the inner parsec

    Energy Technology Data Exchange (ETDEWEB)

    Deegan, Patrick; Nayakshin, Sergei [University of Leicester, University Road, Leicester, LEI 7RH (United Kingdom)

    2006-12-15

    Due to dynamical friction stellar mass black holes should form a cusp in the inner parsec. Calculations [5, 6] show that approximately 20 thousand black holes would be present in a sphere with radius of about a parsec around Sgr A*. The presence of these objects opens up the possibility that they might be accreting ''cool'' gas (i.e. the Minispiral) as discussed by Morris [6]. Here we calculate the X-ray emission expected from these black holes as a method to constrain their population. We find that the data limits the total number of such black holes to around 10 - 20 thousand. Even a much smaller number of such black holes, i.e. 5 thousand, is sufficient to produce several sources with X-ray luminosity above L{sub x} {approx} 10{sup 33} erg s{sup -1} at any one time. We suggest that some of the discrete X-ray sources observed by Muno [7] with Chandra in the inner parsec may be such ''fake X-ray binaries''.

  1. The Nature of the Unresolved Extragalactic Cosmic Soft X-Ray Background

    Science.gov (United States)

    Cappelluti, N.; Ranalli, P.; Roncarelli, M.; Arevalo, P.; Zamorani, G.; Comastri, A.; Gilli, R.; Rovilos, E.; Vignali, C.; Allevato, V.; hide

    2013-01-01

    In this paper we investigate the power spectrum of the unresolved 0.5-2 keV cosmic X-ray background (CXB) with deep Chandra 4-Msec (Ms) observations in the Chandra Deep Field South (CDFS). We measured a signal that, on scales >30 arcsec, is significantly higher than the shot noise and is increasing with angular scale. We interpreted this signal as the joint contribution of clustered undetected sources like active galactic nuclei (AGN), galaxies and the intergalactic medium (IGM). The power of unresolved cosmic source fluctuations accounts for approximately 12 per cent of the 0.5-2 keV extragalactic CXB. Overall, our modelling predicts that approximately 20 per cent of the unresolved CXB flux is produced by low-luminosity AGN, approximately 25 per cent by galaxies and approximately 55 per cent by the IGM. We do not find any direct evidence of the so-called 'warm hot intergalactic medium' (i.e. matter with 10(exp 5) less than T less than 10(exp 7) K and density contrast delta less than 1000), but we estimated that it could produce about 1/7 of the unresolved CXB. We placed an upper limit on the space density of postulated X-ray-emitting early black holes at z greater than 7.5 and compared it with supermassive black hole evolution models.

  2. X-ray Measurements of Black Hole X-ray Binary Source GRS 1915+ ...

    Indian Academy of Sciences (India)

    tribpo

    March 30th, 1997 during a quiescent phase of the source. .... The field of view ... tagged with a 25µsec resolution and transmitted to ground on a 40 Kbit PCM/FM ... only composite model fits for the soft and hard X ray band are used and the ...

  3. Astronomy and astrophysics of galactic X-ray binaries: from the nature of the X-ray sources to the physics of accretion processes

    International Nuclear Information System (INIS)

    Rodriguez, Jerome

    2010-01-01

    In this HDR (Accreditation to supervise research) report, the author proposes an overview of his research works in the field of accretion of X-ray binaries. After a presentation of X-ray binaries, neutron stars and black holes, micro-quasars, and of the main issues regarding X-ray binaries, the author presents and comments his activities in X-ray astronomy and gamma-ray astronomy (the INTEGRAL observatory, the discovery of new sources of X and gamma radiation, studies of new sources at different wavelengths). The second part addresses the understanding of source accretion: phenomenological studies in astronomy, relationships between accretion and ejection. The third part presents and comments several studies of the physics of phenomena related to matter accretion and ejection. (author) [fr

  4. X-RAY EMISSION FROM YOUNG STARS IN THE MASSIVE STAR-FORMING REGION IRAS 20126+4104

    International Nuclear Information System (INIS)

    Anderson, C. N.; Hofner, P.; Creech-Eakman, M.; Shepherd, D.

    2011-01-01

    We present a 40 ks Chandra observation of the IRAS 20126+4104 core region. In the inner 6'' two X-ray sources were detected, which are coincident with the radio jet source I20S and the variable radio source I20Var. No X-ray emission was detected from the nearby massive protostar I20N. The spectra of both detected sources are hard and highly absorbed, with no emission below 3 keV. For I20S, the measured 0.5-8 keV count rate was 4.3 counts ks -1 . The X-ray spectrum was fitted with an absorbed 1T APEC model with an energy of kT =10 keV and an absorbing column of N H = 1.2 x 10 23 cm -2 . An unabsorbed X-ray luminosity of about 1.4 x 10 32 erg s -1 was estimated. The spectrum shows broad line emission between 6.4 and 6.7 keV, indicative of emission from both neutral and highly ionized iron. The X-ray light curve indicates that I20S is marginally variable; however, no flare emission was observed. The variable radio source I20Var was detected with a count rate of 0.9 counts ks -1 but there was no evidence of X-ray variability. The best-fit spectral model is a 1T APEC model with an absorbing hydrogen column of N H = 1.1 x 10 23 cm -2 and a plasma energy of kT = 6.0 keV. The unabsorbed X-ray luminosity is about 3 x 10 31 erg s -1 .

  5. The Secret Lives of Cepheids: δ Cep—The Prototype of a New Class of Pulsating X-Ray Variable Stars

    Science.gov (United States)

    Engle, Scott G.; Guinan, Edward F.; Harper, Graham M.; Cuntz, Manfred; Remage Evans, Nancy; Neilson, Hilding R.; Fawzy, Diaa E.

    2017-03-01

    From our Secret Lives of Cepheids program, the prototype Classical Cepheid, δ Cep, is found to be an X-ray source with periodic pulsation-modulated X-ray variations. This finding complements our earlier reported phase-dependent FUV-UV emissions of the star that increase ˜10-20 times with highest fluxes at ˜ 0.90{--}0.95φ , just prior to maximum brightness. Previously δ Cep was found as potentially X-ray variable, using XMM-Newton observations. Additional phase-constrained data were secured with Chandra near X-ray emission peak, to determine if the emission and variability were pulsation-phase-specific to δ Cep and not transient or due to a possible coronally active, cool companion. The Chandra data were combined with prior XMM-Newton observations, and were found to very closely match the previously observed X-ray behavior. From the combined data set, a ˜4 increase in X-ray flux is measured, reaching a peak {L}{{X}} = 1.7 × 1029 erg s-1 near 0.45ϕ. The precise X-ray flux phasing with the star’s pulsation indicates that the emissions arise from the Cepheid and not from a companion. However, it is puzzling that the maximum X-ray flux occurs ˜0.5ϕ (˜3 days) later than the FUV-UV maximum. There are several other potential Cepheid X-ray detections with properties similar to δ Cep, and comparable X-ray variability is indicated for two other Cepheids: β Dor and V473 Lyr. X-ray generating mechanisms in δ Cep and other Cepheids are discussed. If additional Cepheids are confirmed to show phased X-ray variations, then δ Cep will be the prototype of a new class of pulsation-induced X-ray variables.

  6. 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...

  7. X-RAY AND RADIO EMISSION FROM TYPE IIn SUPERNOVA SN 2010jl

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Poonam [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus, Pune 411 007 (India); Chevalier, Roger A. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Chugai, Nikolai [Institute of Astronomy of Russian Academy of Sciences, Pyatnitskaya St. 48, 109017 Moscow (Russian Federation); Fransson, Claes [Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden); Soderberg, Alicia M., E-mail: poonam@ncra.tifr.res.in [Smithsonian Astrophysical Observatory, 60 Garden St., MS-20, Cambridge, MA 02138 (United States)

    2015-09-01

    We present all X-ray and radio observations of the Type IIn supernova SN 2010jl. The X-ray observations cover a period up to day 1500 with Chandra, XMM-Newton, NuSTAR, and Swift-X-ray Telescope (XRT). The Chandra observations after 2012 June, the XMM-Newton observation in 2013 November, and most of the Swift-XRT observations until 2014 December are presented for the first time. All the spectra can be fitted by an absorbed hot thermal model except for Chandra spectra on 2011 October and 2012 June when an additional component is needed. Although the origin of this component is uncertain, it is spatially coincident with the supernova and occurs when there are changes to the supernova spectrum in the energy range close to that of the extra component, indicating that the emission is related to the supernova. The X-ray light curve shows an initial plateau followed by a steep drop starting at day ∼300. We attribute the drop to a decrease in the circumstellar density. The column density to the X-ray emission drops rapidly with time, showing that the absorption is in the vicinity of the supernova. We also present Very Large Array radio observations of SN 2010jl. Radio emission was detected from SN 2010jl from day 570 onwards. The radio light curves and spectra suggest that the radio luminosity was close to its maximum at the first detection. The velocity of the shocked ejecta derived assuming synchrotron self-absorption is much less than that estimated from the optical and X-ray observations, suggesting that free–free absorption dominates.

  8. Time-resolved materials science opportunities using synchrotron x-ray sources

    International Nuclear Information System (INIS)

    Larson, B.C.; Tischler, J.Z.

    1995-06-01

    The high brightness, high intensity, and pulsed time-structure of synchrotron sources provide new opportunities for time-resolved x-ray diffraction investigations. With third generation synchrotron sources coming on line, high brilliance and high brightness are now available in x-ray beams with the highest flux. In addition to the high average flux, the instantaneous flux available in synchrotron beams is greatly enhanced by the pulsed time structure, which consists of short bursts of x-rays that are separated by ∼tens to hundreds of nanoseconds. Time-resolved one- and two-dimensional position sensitive detection techniques that take advantage of synchrotron radiation for materials science x-ray diffraction investigations are presented, and time resolved materials science applications are discussed in terms of recent diffraction and spectroscopy results and materials research opportunities

  9. 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.

  10. Action at the Horizon: Chandra/EHT Observations of Sgr A*

    Science.gov (United States)

    Neilsen, Joseph

    2017-09-01

    In April 2017, the Event Horizon Telescope will observe Sgr A* with imaging quality sufficient to resolve the shadow of the black hole, while providing a close-up view of accretion at the horizon. As Sgr A* is a well-known source of X-ray flares, coordinated Chandra/EHT observations offer an incredible opportunity: a chance to observe structures (e.g., hotspots) near the event horizon while tracking their high-energy variability. In anticipation of a follow-up campaign in 2018, we are requesting 4x33 ks Chandra observations of Sgr A* to be coordinated with EHT. This campaign will double our chances of simultaneous flares. We will search for flares and hotspots, provide priors for EHT image reconstruction, and track any activity associated with the closest approach of the massive star S0-2.

  11. A CENSUS OF THE SUPERSOFT X-RAY SOURCES IN M31

    International Nuclear Information System (INIS)

    Orio, Marina; Nelson, Thomas; Bianchini, Antonio; Di Mille, Francesco; Harbeck, Daniel

    2010-01-01

    We examined X-ray, ultraviolet, and optical archival data of 89 supersoft X-ray sources (SSS) in M31. We studied the timescales of X-ray variability and searched UV and optical counterparts. Almost a third of the SSS are known classical or recurrent novae, and at least half of the others exhibit the same temporal behavior as post-outburst novae. Non-stellar objects among SSS seem to be rare: less than 10% of the classified SSS turned out to be supernova remnants, and only one source has been identified with an active galactic nucleus in the background. Not more than 20% of the SSS that are not coincident with observed novae are persistent or recurrent X-ray sources. A few of these long-lasting sources show characteristics in common with other SSS identified as white dwarf (WD) close binaries in the Magellanic Clouds and in the Galaxy, including variability on timescales of minutes, possibly indicating the spin period of a WD. Such objects are likely to be low-mass X-ray binaries with a massive WD. A third of the non-nova SSS are in regions of recent star formation, often at the position of an O or B star, and we suggest that they may be high-mass X-ray binaries. If these sources host a massive hydrogen-burning WD, as it seems likely, they may become Type Ia supernovae (SNe Ia), constituting the star formation dependent component of the SNe Ia rate.

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

    International Nuclear Information System (INIS)

    Reyes-Herrera, Juan

    2016-01-01

    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). (paper)

  13. 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).

  14. The Highest Resolution X-ray View of the Nuclear Region of NGC 4151

    Science.gov (United States)

    Wang, Junfeng; Fabbiano, G.; Karovska, M.; Elvis, M.; Risaliti, G.; Zezas, A.; Mundell, C. G.

    2009-09-01

    We report high resolution imaging of the nucleus of the Seyfert 1 galaxy NGC 4151 obtained with a 50 ks Chandra HRC observation. The HRC image resolves the emission on spatial scales of 0.5 arcsec (30 pc), showing an extended X-ray morphology overall consistent with the narrow line region seen in optical line emission. Removal of the bright point-like nuclear source and image deconvolution technique both reveal X-ray enhancements that closely match the substructures seen in the HST [OIII] image and prominent knots in the radio jet. We find that most of the NLR clouds in NGC 4151 have [OIII] to soft X-ray ratio consistent with the values observed in NLRs of some Seyfert 2 galaxies, which indicates a uniform ionization parameter even at large radii and a density dependence ∝ r^{-2} as expected in the disk wind scenario. We examine various X-ray emission mechanisms of the radio jet and consider thermal emission from interaction between radio outflow and the NLR clouds the most probable origin for the X-ray emission associated with the jet.

  15. CANDELS/GOODS-S, CDFS, and ECDFS: photometric redshifts for normal and X-ray-detected galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Li-Ting; Salvato, Mara; Nandra, Kirpal; Brusa, Marcella; Bender, Ralf; Buchner, Johannes; Brightman, Murray; Georgakakis, Antonis [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Donley, Jennifer L. [Los Alamos National Laboratory, Los Alamos, NM (United States); Kocevski, Dale D. [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Guo, Yicheng; Barro, Guillermo; Faber, Sandra M. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States); Hathi, Nimish P. [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Rangel, Cyprian [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Willner, S. P.; Ashby, Matthew L. N. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Budavári, Tamás; Szalay, Alexander S. [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD (United States); Dahlen, Tomas [Space Telescope Science Institute, Baltimore, MD (United States); and others

    2014-11-20

    We present photometric redshifts and associated probability distributions for all detected sources in the Extended Chandra Deep Field South (ECDFS). This work makes use of the most up-to-date data from the Cosmic Assembly Near-IR Deep Legacy Survey (CANDELS) and the Taiwan ECDFS Near-Infrared Survey (TENIS) in addition to other data. We also revisit multi-wavelength counterparts for published X-ray sources from the 4 Ms CDFS and 250 ks ECDFS surveys, finding reliable counterparts for 1207 out of 1259 sources (∼96%). Data used for photometric redshifts include intermediate-band photometry deblended using the TFIT method, which is used for the first time in this work. Photometric redshifts for X-ray source counterparts are based on a new library of active galactic nuclei/galaxy hybrid templates appropriate for the faint X-ray population in the CDFS. Photometric redshift accuracy for normal galaxies is 0.010 and for X-ray sources is 0.014 and outlier fractions are 4% and 5.2%, respectively. The results within the CANDELS coverage area are even better, as demonstrated both by spectroscopic comparison and by galaxy-pair statistics. Intermediate-band photometry, even if shallow, is valuable when combined with deep broadband photometry. For best accuracy, templates must include emission lines.

  16. CANDELS/GOODS-S, CDFS, and ECDFS: photometric redshifts for normal and X-ray-detected galaxies

    International Nuclear Information System (INIS)

    Hsu, Li-Ting; Salvato, Mara; Nandra, Kirpal; Brusa, Marcella; Bender, Ralf; Buchner, Johannes; Brightman, Murray; Georgakakis, Antonis; Donley, Jennifer L.; Kocevski, Dale D.; Guo, Yicheng; Barro, Guillermo; Faber, Sandra M.; Hathi, Nimish P.; Rangel, Cyprian; Willner, S. P.; Ashby, Matthew L. N.; Budavári, Tamás; Szalay, Alexander S.; Dahlen, Tomas

    2014-01-01

    We present photometric redshifts and associated probability distributions for all detected sources in the Extended Chandra Deep Field South (ECDFS). This work makes use of the most up-to-date data from the Cosmic Assembly Near-IR Deep Legacy Survey (CANDELS) and the Taiwan ECDFS Near-Infrared Survey (TENIS) in addition to other data. We also revisit multi-wavelength counterparts for published X-ray sources from the 4 Ms CDFS and 250 ks ECDFS surveys, finding reliable counterparts for 1207 out of 1259 sources (∼96%). Data used for photometric redshifts include intermediate-band photometry deblended using the TFIT method, which is used for the first time in this work. Photometric redshifts for X-ray source counterparts are based on a new library of active galactic nuclei/galaxy hybrid templates appropriate for the faint X-ray population in the CDFS. Photometric redshift accuracy for normal galaxies is 0.010 and for X-ray sources is 0.014 and outlier fractions are 4% and 5.2%, respectively. The results within the CANDELS coverage area are even better, as demonstrated both by spectroscopic comparison and by galaxy-pair statistics. Intermediate-band photometry, even if shallow, is valuable when combined with deep broadband photometry. For best accuracy, templates must include emission lines.

  17. A CHANDRA OBSERVATION OF THE ECLIPSING WOLF-RAYET BINARY CQ Cep

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Stephen L. [CASA, Univ. of Colorado, Boulder, CO 80309-0389 (United States); Zhekov, Svetozar A. [Space Research and Technology Institute, Akad. G. Bonchev Str., Sofia, 1113 (Bulgaria); Güdel, Manuel [Dept. of Astrophysics, Univ. of Vienna, Türkenschanzstr. 17, A-1180 Vienna (Austria); Schmutz, Werner, E-mail: stephen.skinner@colorado.edu, E-mail: szhekov@space.bas.bg, E-mail: manuel.guedel@univie.ac.at, E-mail: werner.schmutz@pmodwrc.ch [Physikalisch-Meteorologisches Observatorium Davos and World Radiation Center (PMOD/WRC), Dorfstrasse 33, CH-7260 Davos Dorf (Switzerland)

    2015-02-01

    The short-period (1.64 d) near-contact eclipsing WN6+O9 binary system CQ Cep provides an ideal laboratory for testing the predictions of X-ray colliding wind shock theory at close separation where the winds may not have reached terminal speeds before colliding. We present results of a Chandra X-ray observation of CQ Cep spanning ∼1 day during which a simultaneous Chandra optical light curve was acquired. Our primary objective was to compare the observed X-ray properties with colliding wind shock theory, which predicts that the hottest shock plasma (T ≳ 20 MK) will form on or near the line-of-centers between the stars. The X-ray spectrum is strikingly similar to apparently single WN6 stars such as WR 134 and spectral lines reveal plasma over a broad range of temperatures T ∼ 4-40 MK. A deep optical eclipse was seen as the O star passed in front of the Wolf-Rayet star and we determine an orbital period P {sub orb} = 1.6412400 d. Somewhat surprisingly, no significant X-ray variability was detected. This implies that the hottest X-ray plasma is not confined to the region between the stars, at odds with the colliding wind picture and suggesting that other X-ray production mechanisms may be at work. Hydrodynamic simulations that account for such effects as radiative cooling and orbital motion will be needed to determine if the new Chandra results can be reconciled with the colliding wind picture.

  18. A Deep X-ray Survey of the Globular Cluster Omega Centauri

    Science.gov (United States)

    Henleywillis, Simon; Cool, Adrienne M.; Haggard, Daryl; Heinke, Craig; Callanan, Paul; Zhao, Yue

    2018-03-01

    We identify 233 X-ray sources, of which 95 are new, in a 222 ks exposure of Omega Centauri with the Chandra X-ray Observatory's ACIS-I detector. The limiting unabsorbed flux in the core is fX(0.5-6.0 keV) ≃ 3×10-16 erg s-1 cm-2 (Lx ≃ 1×1030 erg s-1 at 5.2 kpc). We estimate that ˜60 ± 20 of these are cluster members, of which ˜30 lie within the core (rc = 155 arcsec), and another ˜30 between 1-2 core radii. We identify four new optical counterparts, for a total of 45 likely identifications. Probable cluster members include 18 cataclysmic variables (CVs) and CV candidates, one quiescent low-mass X-ray binary, four variable stars, and five stars that are either associated with ω Cen's anomalous red giant branch, or are sub-subgiants. We estimate that the cluster contains 40 ± 10 CVs with Lx > 1031 erg s-1, confirming that CVs are underabundant in ω Cen relative to the field. Intrinsic absorption is required to fit X-ray spectra of six of the nine brightest CVs, suggesting magnetic CVs, or high-inclination systems. Though no radio millisecond pulsars (MSPs) are currently known in ω Cen, more than 30 unidentified sources have luminosities and X-ray colours like those of MSPs found in other globular clusters; these could be responsible for the Fermi-detected gamma-ray emission from the cluster. Finally, we identify a CH star as the counterpart to the second-brightest X-ray source in the cluster and argue that it is a symbiotic star. This is the first such giant/white dwarf binary to be identified in a globular cluster.

  19. Low-Energy Microfocus X-Ray Source for Enhanced Testing Capability in the Stray Light Facility

    Science.gov (United States)

    Gaskin, Jessica; O'Dell, Stephen; Kolodziejczak, Jeff

    2015-01-01

    Research toward high-resolution, soft x-ray optics (mirrors and gratings) necessary for the next generation large x-ray observatories requires x-ray testing using a low-energy x-ray source with fine angular size (energy microfocus (approximately 0.1 mm spot) x-ray source from TruFocus Corporation that mates directly to the Stray Light Facility (SLF). MSFC X-ray Astronomy team members are internationally recognized for their expertise in the development, fabrication, and testing of grazing-incidence optics for x-ray telescopes. One of the key MSFC facilities for testing novel x-ray instrumentation is the SLF. This facility is an approximately 100-m-long beam line equipped with multiple x-ray sources and detectors. This new source adds to the already robust compliment of instrumentation, allowing MSFC to support additional internal and community x-ray testing needs.

  20. Soft x-ray source by laser produced Xe plasma

    International Nuclear Information System (INIS)

    Amano, Sho; Masuda, Kazuya; Miyamoto, Shuji; Mochizuki, Takayasu

    2010-01-01

    The laser plasma soft X-ray source in the wavelength rage of 5-17 nm was developed, which consisted of the rotating drum system supplying cryogenic Xe target and the high repetition rate pulse Nd:YAG slab laser. We found the maximum conversion efficiency of 30% and it demonstrated the soft X-ray generation with the high repetition rate pulse of 320 pps and the high average power of 20 W. The soft X-ray cylindrical mirror was developed and successfully focused the soft X-ray with an energy intensity of 1.3 mJ/cm 2 . We also succeeded in the plasma debris mitigation with Ar gas. This will allow a long lifetime of the mirror and a focusing power intensity of 400 mW/cm 2 with 320 pps. The high power soft X-ray is useful for various applications. (author)

  1. Plasma x-ray radiation source.

    Science.gov (United States)

    Popkov, N F; Kargin, V I; Ryaslov, E A; Pikar', A S

    1995-01-01

    This paper gives the results of studies on a plasma x-ray source, which enables one to obtain a 2.5-krad radiation dose per pulse over an area of 100 cm2 in the quantum energy range from 20 to 500 keV. Pulse duration is 100 ns. Spectral radiation distributions from a diode under various operation conditions of a plasma are obtained. A Marx generator served as an initial energy source of 120 kJ with a discharge time of T/4 = 10-6 s. A short electromagnetic pulse (10-7 s) was shaped using plasma erosion opening switches.

  2. X-RAY IRRADIATION OF THE LkCa 15 PROTOPLANETARY DISK

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Stephen L. [CASA, University of Colorado, Boulder, CO 80309-0389 (United States); Guedel, Manuel, E-mail: stephen.skinner@colorado.edu, E-mail: manuel.guedel@univie.ac.at [Department of Astronomy, University of Vienna, Tuerkenschanzstr. 17, A-1180 Vienna (Austria)

    2013-03-01

    LkCa 15 in the Taurus star-forming region has recently gained attention as the first accreting T Tauri star likely to host a young protoplanet. High spatial resolution infrared observations have detected the suspected protoplanet within a dust-depleted inner gap of the LkCa 15 transition disk at a distance of {approx}15 AU from the star. If this object's status as a protoplanet is confirmed, then LkCa 15 will serve as a unique laboratory for constraining physical conditions within a planet-forming disk. Previous models of the LkCa 15 disk have accounted for disk heating by the stellar photosphere but have ignored the potential importance of X-ray ionization and heating. We report here the detection of LkCa 15 as a bright X-ray source with Chandra. The X-ray emission is characterized by a cool, heavily absorbed plasma component at kT {sub cool} Almost-Equal-To 0.3 keV and a harder component at kT {sub hot} Almost-Equal-To 5 keV. We use the observed X-ray properties to provide initial estimates of the X-ray ionization and heating rates within the tenuous inner disk. These estimates and the observed X-ray properties of LkCa 15 can be used as a starting point for developing more realistic disk models of this benchmark system.

  3. Comparison of X-ray source concepts for radiographic purposes at OMEGA

    International Nuclear Information System (INIS)

    Jacquet, L.; Primout, M.; Villette, B.; Girard, F.; Oudot, G.

    2013-01-01

    As multi-keV X-ray sources, seven targets including thick and thin foils, metal-lined halfraums and a foil combined with a plastic cylinder, have been shot on Omega in September 2011. Titanium was used as X-ray emitting material for all the sources. Using experimental data and FCI 2 simulation results, we have, for each source type, characterized the emission lobes and determined the spatial directions of maximum multi-keV energy. These results demonstrate the benefit of using a laser drive with a prepulse for both thick and thin foils. The favorable effect of a confinement cylinder for the X-ray emitted from front side by a thin foil has also been experimentally found but is not yet confirmed by the simulations. The temporal waveforms of the X-ray power obtained from the different sources as well as the emission spots at the times of maximum emission are also compared. (authors)

  4. Nuclear Malaysia Plasma Focus Device as a X-ray Source For Radiography Applications

    International Nuclear Information System (INIS)

    Rokiah Mohd Sabri; Abdul Halim Baijan; Siti Aiasah Hashim; Mohd Rizal Mohd Chulan; Wah, L.K.; Mukhlis Mokhtar; Azaman Ahmad; Rosli Che Ros

    2013-01-01

    A 3.375 kJ plasma focus is designed to operate at 13.5 kV for the purpose of studying x-ray source for radiography in Argon discharge. X-rays is detected by using x-ray film from the mammography radiographic plate. The feasibility of the plasma focus as a high intensity flash x-ray source for good contrast in radiography image is presented. (author)

  5. High Brightness, Laser-Driven X-ray Source for Nanoscale Metrology and Femtosecond Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Siders, C W; Crane, J K; Semenov, V; Betts, S; Kozioziemski, B; Wharton, K; Wilks, S; Barbee, T; Stuart, B; Kim, D E; An, J; Barty, C

    2007-02-26

    This project developed and demonstrated a new, bright, ultrafast x-ray source based upon laser-driven K-alpha generation, which can produce an x-ray flux 10 to 100 times greater than current microfocus x-ray tubes. The short-pulse (sub-picosecond) duration of this x-ray source also makes it ideal for observing time-resolved dynamics of atomic motion in solids and thin films.

  6. Flat Field Anomalies in an X-Ray CCD Camera Measured Using a Manson X-Ray Source

    International Nuclear Information System (INIS)

    Michael Haugh

    2008-01-01

    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. It determines how accurately NIF can point the laser beams and 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 2mA, 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 ∼ 12. 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 ±1.5% maximum to minimum. The spectral efficiency was measured at 10 energy bands ranging from 930 eV to 8470 eV. The efficiency pattern follows the properties of Si. The maximum quantum efficiency is 0.71. We observed an energy dependent pixel sensitivity variation that showed continuous change over a large portion of the CCD. The maximum sensitivity variation was >8% at 8470 eV. The geometric pattern did not change at lower energies, but the maximum contrast decreased and was less than the measurement uncertainty below 4 keV. We were also able to observe debris on the CCD chip. The debris showed maximum contrast at the lowest energy used, 930 eV, and disappeared by 4 keV. 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

  7. X-ray optics developments at ESA